Next Article in Journal
A New Electrode Design for Direct Bladder Wall Stimulation: A Pilot Minipig Study with Chronic Testing
Next Article in Special Issue
Novel Insights into the Immunomodulatory Effects of Caryophyllane Sesquiterpenes: A Systematic Review of Preclinical Studies
Previous Article in Journal
Driver Drowsiness Detection by Applying Deep Learning Techniques to Sequences of Images
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Applied Sciences
Volume 12
Issue 3
10.3390/app12031147
applsci-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Probiotic Molecules That Inhibit Inflammatory Diseases

by
Jesus Zamora-Pineda
1,
Olga Kalinina
1,
Barbara A. Osborne
2,3 and
Katherine L. Knight
1,3,*
1
Department of Microbiology and Immunology, Loyola University Chicago, Chicago, IL 60153, USA
2
Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA 01003, USA
3
HasenTech, LLC, Chicago, IL 60601, USA
*
Author to whom correspondence should be addressed.
Appl. Sci. 2022, 12(3), 1147; https://doi.org/10.3390/app12031147
Submission received: 30 November 2021 / Revised: 17 January 2022 / Accepted: 19 January 2022 / Published: 22 January 2022
(This article belongs to the Special Issue Novel Approaches for Natural Product-Derived Immunomodulators)
Browse Figures
Versions Notes

Abstract

:

Featured Application

Exopolysaccharide from Bacillus subtilis induces an anti-inflammatory response that protects mice from several inflammatory diseases, including enteric and blood-borne pathogens, allergic eosinophilia, and graft versus host disease. This EPS, designated EPSBs, has potential as a therapeutic for inflammatory diseases in humans.

Abstract

Consumption of probiotics for health purposes has increased vastly in the past few decades, and yet the scientific evidence to support health benefits from probiotics is only beginning to emerge. As more probiotics are studied, we are beginning to understand the mechanisms of action by which they benefit human health, as well as to identify the bacterial molecules responsible for these benefits. A new era of therapeutics is on the horizon in which purified molecules from probiotics will be used to prevent and treat diseases. In this review, we summarize the active molecules from probiotic bacteria that have been shown to affect innate and adaptive immunity and have health benefits in experimental settings. We focus particularly on the cellular and molecular mechanisms of the probiotic Bacillus subtilis and its active molecule, exopolysaccharide (ESPBs).

1. Introduction Mod

The World Health Organization defines probiotics as “live microorganisms that when administered in adequate amounts, confer a health benefit on the host.” (FAO/WHO 2002). Consumption of live organisms for maintaining good health is a concept accepted by the general population, and in fact, The National Health Interview Survey showed that probiotics were the third most used non-vitamin, non-mineral dietary supplement in 2012 [1]. Despite their popular use, probiotics have yet to be approved for any medical indication by the US Food Drug Administration [2], in part because results from clinical trials on the efficacy of probiotics in the treatment or prevention of disease have been equivocal [3]. The lack of clarity emanating from the clinical trials has created a state of confusion regarding the clinical use of probiotics. Some of the confusion may arise from the use of different probiotic strains, or combinations thereof, batch preparation, and the outcomes readout. Furthermore, humans vary widely in their diets, genetic backgrounds, and gut microbiome composition, all of which likely influence the efficacy of probiotics.
The probiotic bacteria most widely studied belong to the Lactobacillus sp., Bacterioidetes sp., Bifidobacteria sp., and Bacillus sp. These bacteria have been used to treat diarrhea, irritable bowel syndrome [4], and atopic dermatitis [5], among other diseases. Probiotic bacteria can be beneficial to human health, for example, by inhibiting growth of pathogenic bacteria in the intestine and by secreting bioactive metabolites, such as short-chain fatty acids [6]. The use of intact bacteria for clinical interventions can be challenging, however, in part because the administration of bacteria may alter the endogenous microbiome, causing dysbiosis, and also affect intestinal immunity in a manner not yet fully understood. An alternative approach to administering live bacteria is to isolate and administer the active bacterial molecule responsible for the health benefits. As discussed below, we argue that future scientific research into probiotics should focus not only on specific probiotic organisms but more importantly, on identifying the active molecules of these organisms and determining the mechanism of action by which they provide protection from disease. Such a process will lead to probiotic molecules or probiotic-treated host cells as therapeutics. Here we focus on probiotic molecules that affect the innate and/or adaptive immune system.
Bioactive probiotic molecules with anti-inflammatory properties include cell envelope molecules, secreted proteins, and exopolysaccharides, many of which are shown in Table 1. Although bacterial metabolites, such as short-chain fatty acids, lactate, and bacteriocins, can also be active probiotic molecules, we do not discuss them in this review. Instead, we briefly describe cell envelope-associated probiotic molecules, as well as secreted protein and carbohydrate probiotic molecules, and discuss in-depth the anti-inflammatory probiotic exopolysaccharide (EPS) produced by Bacillus subtilis. This EPS designated EPSBs, ameliorates disease due to enteric or blood-borne pathogens, allergic eosinophilia, and graft vs. host disease [7,8,9,10,11,12,13].

2. Cell Envelope Molecules

Probiotics’ cell envelope molecules have immunomodulatory properties that can reduce pro-inflammatory cytokines, increase production of anti-inflammatory IL-10, generate T regulatory cells (Tregs), and help protect from radiation damage. One of the best characterized anti-inflammatory probiotic molecules is the capsular polysaccharide A (PSA) from Bacteroides fragilis. Oral administration of PSA, a zwitterionic polysaccharide, is protective and therapeutic in murine models of colitis and multiple sclerosis by inducing IL-10-secreting Tregs. Protection by PSA is TLR2 and MHCII-dependent, likely due to TLR2 signaling in plasmacytoid dendritic cells to induce Tregs and IL-10 production [15,16,17,18,19,64]. Furthermore, B. fragilis produces glycosphingolipids that decrease the number of invariant natural killer T cells in the colonic lamina propria, leading to improved outcomes in a murine colitis model [21,22]. Recently, B. fragilis PSA was shown to activate colonic DCs and produce IFN-β in a TLR4-dependent manner that enhances resistance to viral infection in murine models [20].
A polysaccharide peptidoglycan complex on L. casei Shirota was shown to improve ileitis and inhibit IL-6/STAT3 signaling in a murine colitis model using bacterial mutants in vivo and purified peptidoglycan in vitro [65]. The oral administration of probiotic L. rhamnosus GG mutant with modified lipoteichoic acid (LTA) molecules improved colitis in a murine model, correlating with decreased TLR expression and pro-inflammatory cytokine secretion [53]. Further, oral gavage with WT L. rhamnosus GG or intraperitoneal (i.p.) injection with L. rhamnosus LTA protected intestinal epithelial cells from radiation injury through the activation of pericryptal macrophages. These macrophages release CXCL12 that binds to CXCR4 on COX-2 expressing mesenchymal stem cells and stimulates the release of PGE, which protects epithelial stem cells from radiation [61]. Supernatants from L. rhamnosus GG cultures also reduced eosinophil numbers, goblet cell numbers, and lung inflammation in an allergy inflammation murine model [54]. Peritoneal administration of isolated peptidoglycan from L. salivarius Ls33 protects mice from chemically induced colitis in a NOD2-IL-10-dependent manner [56]. Other cell wall components from probiotics have been identified as listed in Table 1. As suggested above, these examples illustrate the potential for using purified active components of probiotics to treat human diseases prophylactically and therapeutically.

3. Secreted Molecules

A. Proteins. Numerous extracellular and secreted bacterial proteins are known to diminish inflammation. These include serpin from Bifidobacterium longum, which inhibits eukaryotic elastase-like serine proteases that are dysregulated in inflammatory disorders, such as celiac disease [28,29], and p40 and p75, molecules from Lactobacillus casei BL23 that in vitro protect from disruption of epithelial cell tight junctions induced by hydrogen peroxide in a PKC and MAP kinase-dependent manner [39]. A p40 secreted molecule from L. rhamnosus GG activated EGFR in vitro and, after oral administration, prevented DSS-induced intestinal epithelial damage in mice [40,41]. Moreover, L. casei secretes lactoceptin, which hydrolyzes the pro-inflammatory chemokine IP-10, and its i.p. administration leads to reduced lymphocyte recruitment in an ileitis murine model [38]. Another extracellular molecule that moderates the immune response is flagellin from Escherichia coli Nissle 1917, which induces the release of the antimicrobial peptide β-defensin 2 in epithelial cells in vitro [36]. Other secreted probiotic proteins that can modulate immune responses are summarized in Table 1. These examples illustrate the potential of using extracellular and secreted peptides from probiotics for therapeutic treatments of immune-mediated diseases.
B. Exopolysaccharides. Many probiotics secrete polysaccharides that have anti-inflammatory properties, which can reduce the production of pro-inflammatory cytokines, increase anti-inflammatory cytokines, enhance the intestinal epithelial barrier, and inhibit T cell-dependent immune responses. These polysaccharides are usually obtained by alcohol precipitation from culture supernatants, and the solubilized precipitate is designated as exopolysaccharide (EPS). As discussed below, EPS molecules of different origins vary widely in the anti-inflammatory effects and the mechanism of protection. Although the term “EPS” is used for all of these samples, the composition and structure of them are generally not known. Likely, EPS from different microorganisms have different compositions and structures, leading to diverse functions and mechanisms of immune regulation. A defined classification of EPS from different organisms will require the structure and structure/function relationship of these polysaccharides. In this review, we distinguish the EPS preparations by using superscripts to symbolize the bacterium from which a specific EPS is isolated, e.g., EPSBs from Bacillus subtilis.
Using bacterial mutants, EPSBb from Bifidobacterium breve has been implicated in reducing colitis during Citrobacter rodentium infection in mice [24] and in reducing rates of epithelial cell shedding [26]. Oral administration of EPSBb from B. breve has also been shown to enhance the intestinal barrier integrity, thereby preventing allergen infiltration and food allergy [27]. Another species of Bifidobacterium, the non-aggregating strain IF1-03 B. adolescentis, protects from colitis by inducing IL-10 production, activating dendritic cells (DCs) and macrophages, and increasing the ratio of Treg/Th17 cells in mice [23]. Based on data from a bacterial mutant, EPSBl from still another Bifidobacterium species, B. Longum 35624, dampens pro-inflammatory cytokines and reduces inflammatory symptoms in the T cell transfer colitis model [30], and in an allergy model, EPSBl stimulates the release of IL-10 in a TLR2-dependent manner that reduces recruitment of eosinophils to the lungs [31].
For Lactobacillus, numerous immunomodulatory effects of EPSLh have been identified and are reviewed in Laiño et al. [66]. Oral administration of EPSLh isolated from L. helveticus KLDS1.8701 reduces intestinal inflammation and improves mucosal barrier function in a colitis model [44], whereas EPSLr from L. rhamnosus KL37 inhibits T cell-dependent immune responses and reduces the arthritogenic antibodies in an arthritis murine model [62]. Several other examples of the anti-inflammatory effects of EPS from probiotics are listed in Table 1. While the molecular mechanisms by which EPS induces anti-inflammatory responses are not well understood, it is noteworthy that EPSLp from L. plantarum N-14 reduces TLR4-mediated pro-inflammatory cytokine production by porcine intestinal epithelial cells. This anti-inflammatory response by EPSLp is due to the induction of negative regulators of TLR signaling, especially RP105, a type I transmembrane molecule, considered part of the TLR family [51]. RP105 complexes with the accessory protein, MD1, and together inhibit LPS signaling through the TLR4/MD2 complex [67]. These data suggest that EPS from some probiotic species may dampen an inflammatory response or induce an anti-inflammatory response by binding to receptors that negatively regulate TLR4 signaling. EPS is easily extractable from bacteria, and as the structures and functions become better defined, EPS from numerous microorganisms may become widely used for therapeutic purposes.

4. EPSBs as Probiotic

The EPS (EPSBs) that we study is derived from Bacillus subtilis and induces anti-inflammatory responses that protect mice from several inflammatory diseases. Below, we discuss these diseases, the cells and molecules that promote protection, and the potential of EPSBs as a therapeutic for humans.
A.
C. rodentium-induced colitis. Oral administration of a single dose of B. subtilis spores was first shown to reduce colitis in mice after infection with the enteric pathogen, Citrobacter rodentium [9]. In this model, B. subtilis does not function by reducing the colonization of C. rodentium, but instead alters the inflammatory disease process, as indicated by reduced epithelial hyperplasia, diarrhea, and goblet cell loss (Figure 1). Analysis of B. subtilis mutants revealed that a mutation in epsH, which regulates biofilm synthesis [68], did not protect from disease caused by C. rodentium, suggesting that biofilm-associated carbohydrate exopolysaccharide (EPSBs) was required for protection. EPSBs was isolated and purified by treatment with DNase, RNase, proteinase K, and gel filtration [10,12], and indeed, it protected from disease. In fact, a single intraperitoneal injection of EPSBs (2.5 mg/kg) administered one day prior to or as much as 3 days after infection with C. rodentium, was sufficient to reduce epithelial hyperplasia, diarrhea, and goblet cell loss. Protection by EPSBs is mediated by anti-inflammatory macrophages, sometimes designated as M2 macrophages. Intraperitoneal administration of EPSBs results in the accumulation of macrophages with M2 macrophage markers, IL4Ra, CD206, arginase, and PD-L1 in the peritoneum, and adoptive transfer of these cells to untreated mice protects them from colitis after infection with C. rodentium [10,12]. These findings demonstrate the anti-inflammatory potential of EPSBs, and of the anti-inflammatory macrophages induced by EPSBs.
B.
Systemic infection with Staphylococcus aureus. Similar to infection with the enteric pathogen, C. rodentium, EPSBs also moderates disease caused by infection with blood-borne S. aureus [11]. In this case, EPSBs increases survival by reducing weight loss and systemic inflammation, as evidenced by decreased levels of inflammatory cytokines and chemokines in blood and bacterial burden [11]. EPSBs induced hybrid-like M1/M2 macrophages, which not only inhibited T cell activation, characteristic of M2 macrophages but also inhibited S. aureus growth through reactive oxygen species (ROS), characteristic of M1 macrophages [69]. Together, data from infection by C. rodentium and S. aureus show that EPSBs from B. subtilis induces an anti-inflammatory environment with decreased inflammatory cytokines and increased anti-inflammatory macrophages that limit T cell activation, as well as macrophages that restrict the growth of bacteria.
C.
Allergic eosinophilia. The association of changes in microbiota to allergic disease is well known, not only because of the hygiene hypothesis [70] but also because of a landmark study by Stein et al., who showed that children who grow up in a farm environment with close proximity to farm animals develop considerably fewer allergies than children that grow up without much interaction with farm animals [71]. This “farm effect” is likely explained by the interaction of children with microbes of the farm animals [72]. Swartzendruber et al. orally administered B. subtilis spores to mice and showed that they prevented the development of allergic eosinophilia in response to intranasal administration of house dust mite (HDM) antigen [8]. The infiltration of eosinophils is due in part to cytokines secreted by T cells [73]. Because DCs are also crucial for the activation of T cells and the development of eosinophilia, Swartzendruber et al. hypothesized that EPSBs-treated DCs could mitigate the allergic eosinophilia caused by an allergy to HDM. Intranasal adoptive transfer of EPSBs-treated bone marrow-derived DCs (BMDCs) prevented eosinophilia induced by HDM-pulsed DCs, indicating that EPSBs induces anti-inflammatory DCs, which can prevent an allergic response, as might be predicted by previous studies [70,72].
D.
Graft versus host disease (GvHD). Another T cell-mediated disease attenuated by EPSBs is GvHD, a severe and often lethal complication of hematopoietic stem cell transplantation, which is frequently used to treat leukemia. The devastating effects of GvHD are mediated by alloreactive donor T cells that recognize host antigens as foreign, become activated, and destroy host tissues and organs. Intraperitoneal injection of EPSBs (2.5 mg/kg) administered several times, 7, 5, and 3 days prior to induction of GvHD, increased survival of mice 80 days post GvHD from 10% to 70% (Figure 2). Kalinina et al. assessed inflammation in live mice during GvHD using a caspase-1 reporter mouse to measure inflammasome activation [7]. With this biosensor mouse model, they found that the administration of EPSBs prevented the activation of alloreactive donor T cells, explaining the increased survival of mice. The results showed that EPSBs did not directly affect alloreactive T cells. In mixed lymphocyte reactions (MLR) in vitro, EPSBs-treated BMDCs potently inhibited alloreactive T cells, suggesting that in vivo, EPSBs induces DCs or other innate cells to become inhibitory and prevent the activation of alloreactive T cells, thereby reducing GvHD.

5. Mechanism by Which EPSBs Inhibits Inflammation

The mechanisms by which EPS from different bacteria ameliorate disease are likely to be highly variable, depending on the structure of the EPS. As indicated above, EPSBs affects innate cells, such as macrophages and DCs, converting them into anti-inflammatory cells. EPSBs does not directly affect T cells, either CD4+ or CD8+, even though inflammation in many diseases is caused by both pathogenic T cells. Instead, the effect of EPSBs on T cells occurs primarily through EPSBs-induced anti-inflammatory innate cells. Molecules, thus far, known to be associated with these processes include TLR4, TGF-β, PD-L1, and indoleamine 2,3 dioxygenase (IDO), as discussed below and are shown in Figure 3.

5.1. Cells

In all of the model systems tested, EPSBs inhibits the activation of T cells, but it does not directly affect them [7,10]. Instead, EPSBs induces anti-inflammatory M2-like macrophages and anti-inflammatory DCs, both of which have the capacity to inhibit T cell proliferation. Intraperitoneal injection of EPSBs leads to the induction of peritoneal M2-like macrophages that inhibit proliferation of activated T cells in the C. rodentium colitis model [10,12], as well as hybrid M1-M2-like macrophages in mice infected with S. aureus [11]. These M1-M2-like macrophages not only inhibit T cell activation by S. aureus superantigen but also upregulate ROS and have the capacity to growth arrest S. aureus. For DCs, in vitro stimulation of BMDCs with EPSBs results in anti-inflammatory cells that inhibit alloreactive T cells in MLR and presumably in GvHD [7]. Other cells affected by EPSBs include NK cells, although the mechanism by which this occurs remains a mystery [13].

5.2. Immune Regulator Molecules

1. TLR4. The anti-inflammatory effect of EPSBs requires TLR4, as shown in the disease models for colitis [12], bacterial sepsis [11], and GvHD [7]. The requirement for TLR4 resides in the macrophages and DCs [7,10,12], but TLR4 on other cell types, e.g., epithelial cells, mesenchymal, and NK cells, may also be required for, or contribute to, the protection by EPSBs. Experiments with cell-specific knockout mice will establish the identity of TLR4+ cells required for the anti-inflammatory activity of EPSBs. The finding that EPSBs induces an anti-inflammatory effect through TLR4 is, of course surprising, because TLR4 signaling is associated with an inflammatory response due to LPS signaling. Although LPS is generally associated with pro-inflammatory responses, LPS can also induce tolerance, known as low dose tolerance or endotoxin tolerance. In this case, prolonged administration of LPS [74], or a single low dose of LPS, can dampen inflammation and induce tolerance. The mechanism by which this occurs remains under investigation [75]. Other TLR4-mediated anti-inflammatory responses have also been described and in these cases, the immunoregulatory effect is often mediated by other receptors. For example, the toll-like receptor family protein RP105/MD1 complex is involved in the immunoregulatory effect of EPSLp from Lactobacillus plantarum N14, which inhibits inflammatory TLR4 signaling [51]. Furthermore, Horvatinovich et al. showed that soluble CD83 inhibits T cell activation by binding to the TLR4/MD-2 complex on CD14+ monocytes and altering the signaling cascade to induce the production of anti-inflammatory molecules IDO and IL-10 [76]. Gringhuis et al. showed that the lectin DC-SIGN modulates TLR signaling via Raf-1 kinase-dependent acetylation of the transcription factor NF-κB, which increased the anti-inflammatory response by increasing the transcription of IL-10 [77]. Furthermore, Yao et al. showed that leukadherin-1-mediated activation of CD11b inhibits LPS-induced pro-inflammatory responses in macrophages and protects mice from endotoxic shock by blocking LPS-TLR4 interaction [78]. Lastly, Li et al. showed that galectin-3 is a negative regulator of LPS-mediated inflammation [79]. We hypothesize that EPSBs also engages a receptor that negatively regulates TLR4-mediated signaling.
2. TGF-β and PD-L1. Paynich et al. showed that EPSBs-induced peritoneal M2 macrophages inhibit proliferation and activation of both CD4+ and CD8+ T cells activated with anti-CD3 and anti-CD28 antibodies, in vitro [10]. M2 macrophages are known to mediate an anti-inflammatory response by several molecules, including TGF-β, Arg-1, IL-10, PD-L1, and PD-L2. EPSBs-induced peritoneal M2 macrophages inhibited T cells in a contact-dependent manner, and this inhibition was dependent on TGF-β in the case of CD4+ T cells and on TGF-β and PD-L1 in the case of CD8+ T cells [10]. EPSBs-induced peritoneal M2 macrophages also upregulated Arg-1 and secretion of IL-10, and although these molecules were not required for the inhibition of T cell proliferation and activation in vitro, we predict that they are involved in the EPSBs-induced anti-inflammatory response in vivo.
3. IDO. Kalinina et al. showed that EPSBs induces inhibitory BMDCs that completely inhibited alloreactive T cell proliferation in an MLR [7]. This inhibition was neither dependent on TGF-β or PD-L1, nor on other inhibitory molecules, such as Arg-1, IL-10, CTLA4, and PD-L2. Instead, the EPSBs-induced BMDCs inhibited alloreactive T cells in the MLR through the inhibitory molecule, IDO [7]. EPSBs-treated ido1−/− BMDCs do not inhibit T cell proliferation, and the addition of the IDO inhibitor 1-methyl-l-tryptophan to the MLR cultures with EPSBs-treated WT BMDCs restored T cell proliferation. IDO inhibition of T cell proliferation is due to degradation of the essential amino acid, tryptophan, and the production of tryptophan metabolites, kynurenines [80].

6. Translational Potential of EPSBs

B. subtilis has anti-inflammatory properties and is protective in several T cell-mediated diseases [7,8,9,10,11,12,13]. One molecule of B. subtilis that confers the anti-inflammatory responses is EPSBs, secreted as a part of a biofilm. Using B. subtilis mutants that overexpress and secrete EPS, large quantities of EPSBs can be easily purified for prophylactic or therapeutic administration. Injection of EPSBs confers protection similar to that shown by oral administration of B. subtilis spores [9], and currently, in collaboration with colleagues in Food Science at the University of Massachusetts, we plan to formulate capsules to optimize oral administration of EPSBs. Using an active molecule instead of live bacteria has many advantages: it is not dangerous for immunocompromised patients, it allows for more accurate dosage, its effects are temporary, and it will not alter the intestinal microbiome. Although there is no evidence that EPSBs is toxic to mice, clinical studies will be needed to confirm that it is also not toxic for humans.
Thus far, EPSBs has been used primarily as a prophylactic [7,8,9,10,11,12,13]. However, in studies with C. rodentium-induced colitis, EPSBs injected 3 days post infection also inhibited disease [10], indicating that EPSBs has potential as a therapeutic, especially for patients suffering from acute diarrhea, currently treated with fluid and electrolyte replacement.
Another potential use of EPSBs is for inflammatory bowel disease (IBD), where, in remission, most patients relapse and require treatment [81]. EPSBs could be used in combination with other anti-inflammatory agents not only to achieve remission but also could be used continuously during remission to prevent future relapses. Similarly, seasonal allergies and asthma induce inflammation after contact with allergens or molecular triggers. Because intranasal administration of EPSBs reduces allergic eosinophilia in a murine model [8], it could be used as a preventative medication to prevent allergic and asthma attacks in a prophylactic manner during allergy seasons or when exposure to allergens is unavoidable. This idea is in line with Strachan’s hygiene hypothesis [70], which states that as human settings become free from bacteria, the incidence of allergies rises. By dosing individuals who suffer from allergies with EPSBs, the allergic inflammation flares may be reduced.
EPSBs also shows exciting promise to prevent GvHD where alloreactive T cells become activated and can initiate severe inflammation. In an in vitro MLR, human cells from different MHC types are cultured together, and alloreactive T cells become activated, as in GvHD. If BMDCs treated with EPSBs are added to the MLR cultures, T cell activation is inhibited, whereas with untreated BMDCs no inhibition is observed [7]. It may well be that the administration of EPS to the donor and/or recipient of the graft may limit inflammation and the resultant GvHD. Another possibility is to treat BMDCs in vitro with EPSBs, and then administer them along with the graft. This may be especially helpful for bone marrow transplants in patients with a hematologic malignancy, many of which require bone marrow transplants. Other disease candidates to test the clinical efficacy of EPSBs are chronic diseases, including atopic dermatitis, psoriasis, chronic sinusitis, and eosinophilic esophagitis. These are inflammatory disorders that cycle from remissions to flares or remain at low continuous inflammation. EPSBs can be easily administered for symptom relief.

7. Concluding Remarks

Since Strachan’s [70] hygiene hypothesis, numerous studies have demonstrated the potential of bacteria, especially commensal bacteria to provide health benefits (reviewed in [3]). Such bacteria are now referred to as probiotics and are readily ingested by millions of people in over-the-shelf supplements. As discussed above, most studies with probiotics utilize intact bacteria instead of identifying bioactive bacterial molecules and determining how they can provide health benefits. The advantage to identifying bioactive molecules, such as cell envelope and secreted molecules, is that they can be administered locally, systemically, and by intranasal or oral administration without the potential of developing sepsis, as might occur after the administration of live bacteria.
B. subtilis is one of the probiotics for which a bioactive molecule has been identified. Structural analysis for this and other probiotic molecules will provide the opportunity to synthesize molecules and chemically optimize them for biologic longevity, oral administration, and minimal toxicity. It is quite possible that other compounds, either secreted or derived from bacterial cell envelopes that modulate immune responses are yet to be discovered. We are optimistic that probiotic molecules will provide a new source of bioactive molecules that can prevent or treat numerous inflammatory diseases.

Author Contributions

Conceptualization, J.Z.-P., K.L.K.; Original draft preparation, J.Z.-P.; review and editing, K.L.K., B.A.O., O.K.; funding acquisition, K.L.K., B.A.O. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Institutes of Health: AI110586 (K.L.K.) and AI155281 (K.L.K. & B.A.O.), and from the U. Massachusetts Manning/IALS Innovation Award (B.A.O.).

Conflicts of Interest

The authors have no conflict of interest.

References

  1. Clarke, T.C.; Black, L.I.; Stussman, B.J.; Barnes, P.M.; Nahin, R.L. Trends in the use of complementary health approaches among adults: United States, 2002–2012. Natl. Health Stat. Rep. 2015, 79, 1–16. [Google Scholar]
  2. Venugopalan, V.; Shriner, K.A.; Wong-Beringer, A. Regulatory oversight and safety of probiotic use. Emerg. Infect. Dis. 2010, 16, 1661–1665. [Google Scholar] [CrossRef] [PubMed]
  3. Suez, J.; Zmora, N.; Segal, E.; Elinav, E. The pros, cons, and many unknowns of probiotics. Nat. Med. 2019, 25, 716–729. [Google Scholar] [CrossRef]
  4. Ford, A.C.; Quigley, E.M.; Lacy, B.E.; Lembo, A.J.; Saito, Y.A.; Schiller, L.R.; Soffer, E.E.; Spiegel, B.M.; Moayyedi, P. Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome and chronic idiopathic constipation: Systematic review and meta-analysis. Am. J. Gastroenterol. 2014, 109, 1547–1561. [Google Scholar] [CrossRef]
  5. Li, L.; Han, Z.; Niu, X.; Zhang, G.; Jia, Y.; Zhang, S.; He, C. Probiotic Supplementation for Prevention of Atopic Dermatitis in Infants and Children: A Systematic Review and Meta-analysis. Am. J. Clin. Dermatol. 2019, 20, 367–377. [Google Scholar] [CrossRef] [PubMed]
  6. LeBlanc, J.G.; Chain, F.; Martín, R.; Bermúdez-Humarán, L.G.; Courau, S.; Langella, P. Beneficial effects on host energy metabolism of short-chain fatty acids and vitamins produced by commensal and probiotic bacteria. Microb. Cell Fact. 2017, 16, 79. [Google Scholar] [CrossRef] [Green Version]
  7. Kalinina, O.; Talley, S.; Zamora-Pineda, J.; Paik, W.; Campbell, E.M.; Knight, K.L. Amelioration of Graft-versus-Host Disease by Exopolysaccharide from a Commensal Bacterium. J. Immunol. 2021, 206, 2101–2108. [Google Scholar] [CrossRef]
  8. Swartzendruber, J.A.; Incrocci, R.W.; Wolf, S.A.; Jung, A.; Knight, K.L. Bacillus subtilis exopolysaccharide prevents allergic eosinophilia. Allergy 2019, 74, 819–821. [Google Scholar] [CrossRef] [PubMed]
  9. Jones, S.E.; Knight, K.L. Bacillus subtilis-mediated protection from Citrobacter rodentium-associated enteric disease requires espH and functional flagella. Infect. Immun. 2012, 80, 710–719. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  10. Paynich, M.L.; Jones-Burrage, S.E.; Knight, K.L. Exopolysaccharide from Bacillus subtilis Induces Anti-Inflammatory M2 Macrophages That Prevent T Cell-Mediated Disease. J. Immunol. 2017, 198, 2689–2698. [Google Scholar] [CrossRef] [Green Version]
  11. Paik, W.; Alonzo, F., 3rd; Knight, K.L. Probiotic Exopolysaccharide Protects against Systemic Staphylococcus aureus Infection, Inducing Dual-Functioning Macrophages That Restrict Bacterial Growth and Limit Inflammation. Infect. Immun. 2019, 87, e00791-18. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  12. Jones, S.E.; Paynich, M.L.; Kearns, D.B.; Knight, K.L. Protection from intestinal inflammation by bacterial exopolysaccharides. J. Immunol. 2014, 192, 4813–4820. [Google Scholar] [CrossRef] [Green Version]
  13. Paik, W.; Alonzo, F., 3rd; Knight, K.L. Suppression of Staphylococcus aureus Superantigen-Independent Interferon Gamma Response by a Probiotic Polysaccharide. Infect. Immun 2020, 88, e00661-19. [Google Scholar] [CrossRef] [PubMed]
  14. Zhang, B.; Fang, L.; Wu, H.M.; Ding, P.S.; Xu, K.; Liu, R.Y. Mer receptor tyrosine kinase negatively regulates lipoteichoic acid-induced inflammatory response via PI3K/Akt and SOCS3. Mol. Immunol. 2016, 76, 98–107. [Google Scholar] [CrossRef] [PubMed]
  15. Wang, Q.; McLoughlin, R.M.; Cobb, B.A.; Charrel-Dennis, M.; Zaleski, K.J.; Golenbock, D.; Tzianabos, A.O.; Kasper, D.L. A bacterial carbohydrate links innate and adaptive responses through Toll-like receptor 2. J. Exp. Med. 2006, 203, 2853–2863. [Google Scholar] [CrossRef] [Green Version]
  16. Ochoa-Repáraz, J.; Mielcarz, D.W.; Ditrio, L.E.; Burroughs, A.R.; Begum-Haque, S.; Dasgupta, S.; Kasper, D.L.; Kasper, L.H. Central nervous system demyelinating disease protection by the human commensal Bacteroides fragilis depends on polysaccharide A expression. J. Immunol. 2010, 185, 4101–4108. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  17. Mazmanian, S.K.; Round, J.L.; Kasper, D.L. A microbial symbiosis factor prevents intestinal inflammatory disease. Nature 2008, 453, 620–625. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  18. Round, J.L.; Lee, S.M.; Li, J.; Tran, G.; Jabri, B.; Chatila, T.A.; Mazmanian, S.K. The Toll-like receptor 2 pathway establishes colonization by a commensal of the human microbiota. Science 2011, 332, 974–977. [Google Scholar] [CrossRef] [Green Version]
  19. Ochoa-Repáraz, J.; Mielcarz, D.W.; Wang, Y.; Begum-Haque, S.; Dasgupta, S.; Kasper, D.L.; Kasper, L.H. A polysaccharide from the human commensal Bacteroides fragilis protects against CNS demyelinating disease. Mucosal Immunol. 2010, 3, 487–495. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  20. Stefan, K.L.; Kim, M.V.; Iwasaki, A.; Kasper, D.L. Commensal Microbiota Modulation of Natural Resistance to Virus Infection. Cell 2020, 183, 1312–1324.e10. [Google Scholar] [CrossRef]
  21. An, D.; Oh, S.F.; Olszak, T.; Neves, J.F.; Avci, F.Y.; Erturk-Hasdemir, D.; Lu, X.; Zeissig, S.; Blumberg, R.S.; Kasper, D.L. Sphingolipids from a symbiotic microbe regulate homeostasis of host intestinal natural killer T cells. Cell 2014, 156, 123–133. [Google Scholar] [CrossRef] [Green Version]
  22. Wieland Brown, L.C.; Penaranda, C.; Kashyap, P.C.; Williams, B.B.; Clardy, J.; Kronenberg, M.; Sonnenburg, J.L.; Comstock, L.E.; Bluestone, J.A.; Fischbach, M.A. Production of α-galactosylceramide by a prominent member of the human gut microbiota. PLoS Biol. 2013, 11, e1001610. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  23. Yu, R.; Zuo, F.; Ma, H.; Chen, S. Exopolysaccharide-Producing Bifidobacterium adolescentis Strains with Similar Adhesion Property Induce Differential Regulation of Inflammatory Immune Response in Treg/Th17 Axis of DSS-Colitis Mice. Nutrients 2019, 11, 782. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  24. Fanning, S.; Hall, L.J.; Cronin, M.; Zomer, A.; MacSharry, J.; Goulding, D.; Motherway, M.O.; Shanahan, F.; Nally, K.; Dougan, G.; et al. Bifidobacterial surface-exopolysaccharide facilitates commensal-host interaction through immune modulation and pathogen protection. Proc. Natl. Acad. Sci. USA 2012, 109, 2108–2113. [Google Scholar] [CrossRef] [Green Version]
  25. Hickey, A.; Stamou, P.; Udayan, S.; Ramón-Vázquez, A.; Esteban-Torres, M.; Bottacini, F.; Woznicki, J.A.; Hughes, O.; Melgar, S.; Ventura, M.; et al. Bifidobacterium breve Exopolysaccharide Blocks Dendritic Cell Maturation and Activation of CD4+ T Cells. Front. Microbiol. 2021, 12, 653587. [Google Scholar] [CrossRef]
  26. Hughes, K.R.; Harnisch, L.C.; Alcon-Giner, C.; Mitra, S.; Wright, C.J.; Ketskemety, J.; van Sinderen, D.; Watson, A.J.; Hall, L.J. Bifidobacterium breve reduces apoptotic epithelial cell shedding in an exopolysaccharide and MyD88-dependent manner. Open Biol. 2017, 7, 160155. [Google Scholar] [CrossRef] [Green Version]
  27. Luo, M.; Gan, M.; Yu, X.; Wu, X.; Xu, F. Study on the regulatory effects and mechanisms of action of bifidobacterial exopolysaccharides on anaphylaxes in mice. Int. J. Biol. Macromol. 2020, 165, 1447–1454. [Google Scholar] [CrossRef] [PubMed]
  28. Ivanov, D.; Emonet, C.; Foata, F.; Affolter, M.; Delley, M.; Fisseha, M.; Blum-Sperisen, S.; Kochhar, S.; Arigoni, F. A serpin from the gut bacterium Bifidobacterium longum inhibits eukaryotic elastase-like serine proteases. J. Biol. Chem. 2006, 281, 17246–17252. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  29. McCarville, J.L.; Dong, J.; Caminero, A.; Bermudez-Brito, M.; Jury, J.; Murray, J.A.; Duboux, S.; Steinmann, M.; Delley, M.; Tangyu, M.; et al. A Commensal Bifidobacterium longum Strain Prevents Gluten-Related Immunopathology in Mice through Expression of a Serine Protease Inhibitor. Appl. Environ. Microbiol. 2017, 83, e01323-17. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  30. Schiavi, E.; Gleinser, M.; Molloy, E.; Groeger, D.; Frei, R.; Ferstl, R.; Rodriguez-Perez, N.; Ziegler, M.; Grant, R.; Moriarty, T.F.; et al. The Surface-Associated Exopolysaccharide of Bifidobacterium longum 35624 Plays an Essential Role in Dampening Host Proinflammatory Responses and Repressing Local TH17 Responses. Appl. Environ. Microbiol. 2016, 82, 7185–7196. [Google Scholar] [CrossRef] [Green Version]
  31. Schiavi, E.; Plattner, S.; Rodriguez-Perez, N.; Barcik, W.; Frei, R.; Ferstl, R.; Kurnik-Lucka, M.; Groeger, D.; Grant, R.; Roper, J.; et al. Exopolysaccharide from Bifidobacterium longum subsp. longum 35624™ modulates murine allergic airway responses. Benef. Microbes 2018, 9, 761–773. [Google Scholar] [CrossRef] [PubMed]
  32. Yan, S.; Yang, B.; Zhao, J.; Zhao, J.; Stanton, C.; Ross, R.P.; Zhang, H.; Chen, W. A ropy exopolysaccharide producing strain Bifidobacterium longum subsp. longum YS108R alleviates DSS-induced colitis by maintenance of the mucosal barrier and gut microbiota modulation. Food Funct. 2019, 10, 1595–1608. [Google Scholar] [CrossRef] [PubMed]
  33. O’Connell Motherway, M.; Zomer, A.; Leahy, S.C.; Reunanen, J.; Bottacini, F.; Claesson, M.J.; O’Brien, F.; Flynn, K.; Casey, P.G.; Munoz, J.A.; et al. Functional genome analysis of Bifidobacterium breve UCC2003 reveals type IVb tight adherence (Tad) pili as an essential and conserved host-colonization factor. Proc. Natl. Acad. Sci. USA 2011, 108, 11217–11222. [Google Scholar] [CrossRef] [Green Version]
  34. Vargas García, C.E.; Petrova, M.; Claes, I.J.; De Boeck, I.; Verhoeven, T.L.; Dilissen, E.; von Ossowski, I.; Palva, A.; Bullens, D.M.; Vanderleyden, J.; et al. Piliation of Lactobacillus rhamnosus GG promotes adhesion, phagocytosis, and cytokine modulation in macrophages. Appl. Environ. Microbiol. 2015, 81, 2050–2062. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  35. Turroni, F.; Serafini, F.; Foroni, E.; Duranti, S.; O’Connell Motherway, M.; Taverniti, V.; Mangifesta, M.; Milani, C.; Viappiani, A.; Roversi, T.; et al. Role of sortase-dependent pili of Bifidobacterium bifidum PRL2010 in modulating bacterium-host interactions. Proc. Natl. Acad. Sci. USA 2013, 110, 11151–11156. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  36. Schlee, M.; Wehkamp, J.; Altenhoefer, A.; Oelschlaeger, T.A.; Stange, E.F.; Fellermann, K. Induction of human beta-defensin 2 by the probiotic Escherichia coli Nissle 1917 is mediated through flagellin. Infect. Immun. 2007, 75, 2399–2407. [Google Scholar] [CrossRef] [Green Version]
  37. Konstantinov, S.R.; Smidt, H.; de Vos, W.M.; Bruijns, S.C.; Singh, S.K.; Valence, F.; Molle, D.; Lortal, S.; Altermann, E.; Klaenhammer, T.R.; et al. S layer protein A of Lactobacillus acidophilus NCFM regulates immature dendritic cell and T cell functions. Proc. Natl. Acad. Sci. USA 2008, 105, 19474–19479. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  38. von Schillde, M.A.; Hörmannsperger, G.; Weiher, M.; Alpert, C.A.; Hahne, H.; Bäuerl, C.; van Huynegem, K.; Steidler, L.; Hrncir, T.; Pérez-Martínez, G.; et al. Lactocepin secreted by Lactobacillus exerts anti-inflammatory effects by selectively degrading proinflammatory chemokines. Cell Host Microbe 2012, 11, 387–396. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  39. Seth, A.; Yan, F.; Polk, D.B.; Rao, R.K. Probiotics ameliorate the hydrogen peroxide-induced epithelial barrier disruption by a PKC- and MAP kinase-dependent mechanism. Am. J. Physiol. Gastrointest. Liver Physiol. 2008, 294, G1060–G1069. [Google Scholar] [CrossRef] [Green Version]
  40. Yan, F.; Cao, H.; Cover, T.L.; Washington, M.K.; Shi, Y.; Liu, L.; Chaturvedi, R.; Peek, R.M., Jr.; Wilson, K.T.; Polk, D.B. Colon-specific delivery of a probiotic-derived soluble protein ameliorates intestinal inflammation in mice through an EGFR-dependent mechanism. J. Clin. Investig. 2011, 121, 2242–2253. [Google Scholar] [CrossRef] [Green Version]
  41. Yan, F.; Cao, H.; Cover, T.L.; Whitehead, R.; Washington, M.K.; Polk, D.B. Soluble proteins produced by probiotic bacteria regulate intestinal epithelial cell survival and growth. Gastroenterology 2007, 132, 562–575. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  42. Yasuda, E.; Serata, M.; Sako, T. Suppressive effect on activation of macrophages by Lactobacillus casei strain Shirota genes determining the synthesis of cell wall-associated polysaccharides. Appl. Environ. Microbiol. 2008, 74, 4746–4755. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  43. Matsumoto, S.; Hara, T.; Hori, T.; Mitsuyama, K.; Nagaoka, M.; Tomiyasu, N.; Suzuki, A.; Sata, M. Probiotic Lactobacillus-induced improvement in murine chronic inflammatory bowel disease is associated with the down-regulation of pro-inflammatory cytokines in lamina propria mononuclear cells. Clin. Exp. Immunol. 2005, 140, 417–426. [Google Scholar] [CrossRef]
  44. Liu, Y.; Zheng, S.; Cui, J.; Guo, T.; Zhang, J.; Li, B. Alleviative Effects of Exopolysaccharide Produced by Lactobacillus helveticus KLDS1.8701 on Dextran Sulfate Sodium-Induced Colitis in Mice. Microorganisms 2021, 9, 2086. [Google Scholar] [CrossRef] [PubMed]
  45. Vinderola, G.; Perdigón, G.; Duarte, J.; Farnworth, E.; Matar, C. Effects of the oral administration of the exopolysaccharide produced by Lactobacillus kefiranofaciens on the gut mucosal immunity. Cytokine 2006, 36, 254–260. [Google Scholar] [CrossRef]
  46. Al-Hassi, H.O.; Mann, E.R.; Sanchez, B.; English, N.R.; Peake, S.T.; Landy, J.; Man, R.; Urdaci, M.; Hart, A.L.; Fernandez-Salazar, L.; et al. Altered human gut dendritic cell properties in ulcerative colitis are reversed by Lactobacillus plantarum extracellular encrypted peptide STp. Mol. Nutr. Food Res. 2014, 58, 1132–1143. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  47. Kim, Y.; Lee, Y.D.; Kim, M.; Kim, H.; Chung, D.K. Combination treatment with lipoteichoic acids isolated from Lactobacillus plantarum and Staphylococcus aureus alleviates atopic dermatitis via upregulation of CD55 and CD59. Immunol. Lett. 2019, 214, 23–29. [Google Scholar] [CrossRef] [PubMed]
  48. Ahn, J.E.; Kim, H.; Chung, D.K. Lipoteichoic Acid Isolated from Lactobacillus plantarum Maintains Inflammatory Homeostasis through Regulation of Th1- and Th2-Induced Cytokines. J. Microbiol. Biotechnol. 2019, 29, 151–159. [Google Scholar] [CrossRef]
  49. Jeon, B.; Kim, H.R.; Kim, H.; Chung, D.K. In vitro and in vivo downregulation of C3 by lipoteichoic acid isolated from Lactobacillus plantarum K8 suppressed cytokine-mediated complement system activation. FEMS Microbiol. Lett. 2016, 363, fnw140. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  50. Kwon, M.; Lee, J.; Park, S.; Kwon, O.H.; Seo, J.; Roh, S. Exopolysaccharide Isolated from Lactobacillus plantarum L-14 Has Anti-Inflammatory Effects via the Toll-Like Receptor 4 Pathway in LPS-Induced RAW 264.7 Cells. Int. J. Mol. Sci. 2020, 21, 9283. [Google Scholar] [CrossRef]
  51. Murofushi, Y.; Villena, J.; Morie, K.; Kanmani, P.; Tohno, M.; Shimazu, T.; Aso, H.; Suda, Y.; Hashiguchi, K.; Saito, T.; et al. The toll-like receptor family protein RP105/MD1 complex is involved in the immunoregulatory effect of exopolysaccharides from Lactobacillus plantarum N14. Mol. Immunol. 2015, 64, 63–75. [Google Scholar] [CrossRef]
  52. Lebeer, S.; Claes, I.; Tytgat, H.L.; Verhoeven, T.L.; Marien, E.; von Ossowski, I.; Reunanen, J.; Palva, A.; Vos, W.M.; Keersmaecker, S.C.; et al. Functional analysis of Lactobacillus rhamnosus GG pili in relation to adhesion and immunomodulatory interactions with intestinal epithelial cells. Appl. Environ. Microbiol. 2012, 78, 185–193. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  53. Claes, I.J.; Lebeer, S.; Shen, C.; Verhoeven, T.L.; Dilissen, E.; De Hertogh, G.; Bullens, D.M.; Ceuppens, J.L.; Van Assche, G.; Vermeire, S.; et al. Impact of lipoteichoic acid modification on the performance of the probiotic Lactobacillus rhamnosus GG in experimental colitis. Clin. Exp. Immunol. 2010, 162, 306–314. [Google Scholar] [CrossRef] [PubMed]
  54. Harb, H.; van Tol, E.A.; Heine, H.; Braaksma, M.; Gross, G.; Overkamp, K.; Hennen, M.; Alrifai, M.; Conrad, M.L.; Renz, H.; et al. Neonatal supplementation of processed supernatant from Lactobacillus rhamnosus GG improves allergic airway inflammation in mice later in life. Clin. Exp. Allergy 2013, 43, 353–364. [Google Scholar] [CrossRef] [PubMed]
  55. You, G.E.; Jung, B.J.; Kim, H.R.; Kim, H.G.; Kim, T.R.; Chung, D.K. Lactobacillus sakei lipoteichoic acid inhibits MMP-1 induced by UVA in normal dermal fibroblasts of human. J. Microbiol. Biotechnol. 2013, 23, 1357–1364. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  56. Macho Fernandez, E.; Valenti, V.; Rockel, C.; Hermann, C.; Pot, B.; Boneca, I.G.; Grangette, C. Anti-inflammatory capacity of selected lactobacilli in experimental colitis is driven by NOD2-mediated recognition of a specific peptidoglycan-derived muropeptide. Gut 2011, 60, 1050–1059. [Google Scholar] [CrossRef]
  57. Kaji, R.; Kiyoshima-Shibata, J.; Nagaoka, M.; Nanno, M.; Shida, K. Bacterial teichoic acids reverse predominant IL-12 production induced by certain lactobacillus strains into predominant IL-10 production via TLR2-dependent ERK activation in macrophages. J. Immunol. 2010, 184, 3505–3513. [Google Scholar] [CrossRef] [Green Version]
  58. Dinić, M.; Pecikoza, U.; Djokić, J.; Stepanović-Petrović, R.; Milenković, M.; Stevanović, M.; Filipović, N.; Begović, J.; Golić, N.; Lukić, J. Exopolysaccharide Produced by Probiotic Strain Lactobacillus paraplantarum BGCG11 Reduces Inflammatory Hyperalgesia in Rats. Front. Pharmacol. 2018, 9, 1. [Google Scholar] [CrossRef] [PubMed]
  59. Zhou, X.; Qi, W.; Hong, T.; Xiong, T.; Gong, D.; Xie, M.; Nie, S. Exopolysaccharides from Lactobacillus plantarum NCU116 Regulate Intestinal Barrier Function via STAT3 Signaling Pathway. J. Agric. Food Chem. 2018, 66, 9719–9727. [Google Scholar] [CrossRef] [PubMed]
  60. Li, J.; Li, Q.; Gao, N.; Wang, Z.; Li, F.; Li, J.; Shan, A. Exopolysaccharides produced by Lactobacillus rhamnosus GG alleviate hydrogen peroxide-induced intestinal oxidative damage and apoptosis through the Keap1/Nrf2 and Bax/Bcl-2 pathways in vitro. Food Funct. 2021, 12, 9632–9641. [Google Scholar] [CrossRef]
  61. Riehl, T.E.; Alvarado, D.; Ee, X.; Zuckerman, A.; Foster, L.; Kapoor, V.; Thotala, D.; Ciorba, M.A.; Stenson, W.F. Lactobacillus rhamnosus GG protects the intestinal epithelium from radiation injury through release of lipoteichoic acid, macrophage activation and the migration of mesenchymal stem cells. Gut 2019, 68, 1003–1013. [Google Scholar] [CrossRef]
  62. Nowak, B.; Śróttek, M.; Ciszek-Lenda, M.; Skałkowska, A.; Gamian, A.; Górska, S.; Marcinkiewicz, J. Exopolysaccharide from Lactobacillus rhamnosus KL37 Inhibits T Cell-dependent Immune Response in Mice. Arch. Immunol. Ther. Exp. 2020, 68, 17. [Google Scholar] [CrossRef] [PubMed]
  63. Le Maréchal, C.; Peton, V.; Plé, C.; Vroland, C.; Jardin, J.; Briard-Bion, V.; Durant, G.; Chuat, V.; Loux, V.; Foligné, B.; et al. Surface proteins of Propionibacterium freudenreichii are involved in its anti-inflammatory properties. J. Proteom. 2015, 113, 447–461. [Google Scholar] [CrossRef]
  64. Mazmanian, S.K.; Liu, C.H.; Tzianabos, A.O.; Kasper, D.L. An immunomodulatory molecule of symbiotic bacteria directs maturation of the host immune system. Cell 2005, 122, 107–118. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  65. Matsumoto, S.; Hara, T.; Nagaoka, M.; Mike, A.; Mitsuyama, K.; Sako, T.; Yamamoto, M.; Kado, S.; Takada, T. A component of polysaccharide peptidoglycan complex on Lactobacillus induced an improvement of murine model of inflammatory bowel disease and colitis-associated cancer. Immunology 2009, 128, e170–e180. [Google Scholar] [CrossRef] [PubMed]
  66. Laiño, J.; Villena, J.; Kanmani, P.; Kitazawa, H. Immunoregulatory Effects Triggered by Lactic Acid Bacteria Exopolysaccharides: New Insights into Molecular Interactions with Host Cells. Microorganisms 2016, 4, 27. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  67. Divanovic, S.; Trompette, A.; Atabani, S.F.; Madan, R.; Golenbock, D.T.; Visintin, A.; Finberg, R.W.; Tarakhovsky, A.; Vogel, S.N.; Belkaid, Y.; et al. Inhibition of TLR-4/MD-2 signaling by RP105/MD-1. J. Endotoxin Res. 2005, 11, 363–368. [Google Scholar] [CrossRef] [PubMed]
  68. Kearns, D.B.; Chu, F.; Branda, S.S.; Kolter, R.; Losick, R. A master regulator for biofilm formation by Bacillus subtilis. Mol. Microbiol. 2005, 55, 739–749. [Google Scholar] [CrossRef] [PubMed]
  69. Flannagan, R.S.; Heit, B.; Heinrichs, D.E. Antimicrobial Mechanisms of Macrophages and the Immune Evasion Strategies of Staphylococcus aureus. Pathogens 2015, 4, 826–868. [Google Scholar] [CrossRef] [Green Version]
  70. Strachan, D.P. Hay fever, hygiene, and household size. BMJ 1989, 299, 1259–1260. [Google Scholar] [CrossRef] [Green Version]
  71. Stein, M.M.; Hrusch, C.L.; Gozdz, J.; Igartua, C.; Pivniouk, V.; Murray, S.E.; Ledford, J.G.; Marques Dos Santos, M.; Anderson, R.L.; Metwali, N.; et al. Innate Immunity and Asthma Risk in Amish and Hutterite Farm Children. N. Engl. J. Med. 2016, 375, 411–421. [Google Scholar] [CrossRef] [Green Version]
  72. Ober, C.; Sperling, A.I.; von Mutius, E.; Vercelli, D. Immune development and environment: Lessons from Amish and Hutterite children. Curr. Opin. Immunol. 2017, 48, 51–60. [Google Scholar] [CrossRef] [PubMed]
  73. Okudaira, H.; Nogami, M.; Matsuzaki, G.; Dohi, M.; Suko, M.; Kasuya, S.; Takatsu, K. T-cell-dependent accumulation of eosinophils in the lung and its inhibition by monoclonal anti-interleukin-5. Int. Arch. Allergy Appl. Immunol. 1991, 94, 171–173. [Google Scholar] [CrossRef]
  74. Biswas, S.K.; Lopez-Collazo, E. Endotoxin tolerance: New mechanisms, molecules and clinical significance. Trends Immunol. 2009, 30, 475–487. [Google Scholar] [CrossRef] [PubMed]
  75. Seeley, J.J.; Ghosh, S. Molecular mechanisms of innate memory and tolerance to LPS. J. Leukoc. Biol. 2017, 101, 107–119. [Google Scholar] [CrossRef] [PubMed]
  76. Horvatinovich, J.M.; Grogan, E.W.; Norris, M.; Steinkasserer, A.; Lemos, H.; Mellor, A.L.; Tcherepanova, I.Y.; Nicolette, C.A.; DeBenedette, M.A. Soluble CD83 Inhibits T Cell Activation by Binding to the TLR4/MD-2 Complex on CD14+ Monocytes. J. Immunol. 2017, 198, 2286–2301. [Google Scholar] [CrossRef] [Green Version]
  77. Gringhuis, S.I.; den Dunnen, J.; Litjens, M.; van Het Hof, B.; van Kooyk, Y.; Geijtenbeek, T.B. C-type lectin DC-SIGN modulates Toll-like receptor signaling via Raf-1 kinase-dependent acetylation of transcription factor NF-kappaB. Immunity 2007, 26, 605–616. [Google Scholar] [CrossRef] [Green Version]
  78. Yao, X.; Dong, G.; Zhu, Y.; Yan, F.; Zhang, H.; Ma, Q.; Fu, X.; Li, X.; Zhang, Q.; Zhang, J.; et al. Leukadherin-1-Mediated Activation of CD11b Inhibits LPS-Induced Pro-inflammatory Response in Macrophages and Protects Mice Against Endotoxic Shock by Blocking LPS-TLR4 Interaction. Front. Immunol. 2019, 10, 215. [Google Scholar] [CrossRef]
  79. Li, Y.; Komai-Koma, M.; Gilchrist, D.S.; Hsu, D.K.; Liu, F.T.; Springall, T.; Xu, D. Galectin-3 is a negative regulator of lipopolysaccharide-mediated inflammation. J. Immunol. 2008, 181, 2781–2789. [Google Scholar] [CrossRef] [Green Version]
  80. Terness, P.; Bauer, T.M.; Röse, L.; Dufter, C.; Watzlik, A.; Simon, H.; Opelz, G. Inhibition of allogeneic T cell proliferation by indoleamine 2,3-dioxygenase-expressing dendritic cells: Mediation of suppression by tryptophan metabolites. J. Exp. Med. 2002, 196, 447–457. [Google Scholar] [CrossRef] [Green Version]
  81. Bressler, B.; Marshall, J.K.; Bernstein, C.N.; Bitton, A.; Jones, J.; Leontiadis, G.I.; Panaccione, R.; Steinhart, A.H.; Tse, F.; Feagan, B. Clinical practice guidelines for the medical management of nonhospitalized ulcerative colitis: The Toronto consensus. Gastroenterology 2015, 148, 1035–1058.e3. [Google Scholar] [CrossRef] [PubMed] [Green Version]
Applsci 12 01147 g001 550
Figure 1. Colonic histological analysis of the effect of B. subtilis spores in C. rodentium disease 10 days post infection. Note goblet cells present in normal tissue (arrows), but reduced in colon infected with C. rodentium. Reprinted from [9].
Figure 1. Colonic histological analysis of the effect of B. subtilis spores in C. rodentium disease 10 days post infection. Note goblet cells present in normal tissue (arrows), but reduced in colon infected with C. rodentium. Reprinted from [9].
Applsci 12 01147 g001
Applsci 12 01147 g002 550
Figure 2. Kaplan–Meier survival curves of mice undergoing acute graft versus host disease (GvHD) after treatment with B. subtilis exopolysaccharide (EPSBs), or the negative control ΔEPSBs. ΔEPSBs is purified from a B. subtilis mutant epsH, which does not produce EPS associated with biofilms. Adapted from [7].
Figure 2. Kaplan–Meier survival curves of mice undergoing acute graft versus host disease (GvHD) after treatment with B. subtilis exopolysaccharide (EPSBs), or the negative control ΔEPSBs. ΔEPSBs is purified from a B. subtilis mutant epsH, which does not produce EPS associated with biofilms. Adapted from [7].
Applsci 12 01147 g002
Applsci 12 01147 g003 550
Figure 3. Summary of cellular and molecular effects of EPSBs on disease-induced inflammatory processes.
Figure 3. Summary of cellular and molecular effects of EPSBs on disease-induced inflammatory processes.
Applsci 12 01147 g003
Table
Table 1. Probiotic bacterial molecules with anti-inflammatory activity.
Table 1. Probiotic bacterial molecules with anti-inflammatory activity.
OrganismMoleculeResultsReference
Bacillus subtilisLipoteichoic acid (LTA)


EPSBs		LTA activates a TLR2-dependent inflammatory response and concomitantly induces activation of MerTK signaling to counteract the inflammation in vitro.
EPSBs reduces Citrobacter rodentium infection and generates peritoneal anti-inflammatory macrophages.
EPSBs prevents allergic eosinophilia.
EPSBs ameliorates GvHD and can generate tolerogenic DCs in vitro.
EPSBs protects against systemic infection of Staphylococcus aureus.		[14]



[9]
[10,12]

[8]
[7]

[11,13]
Bacteroides fragilisPolysaccharide A (PSA)







Glycosphingolipids		PSA is protective and therapeutic in murine models of colitis and multiple sclerosis via the induction of IL-10 secreting Tregs.
PSA activates colonic DCs and produces IFN-β that enhances resistance to viral infection in murine models. This protection is dependent on TLR4.
Glycosphingolipids decrease the number of invariant natural killer T cells in the colonic lamina propria leading to improved outcomes in a murine colitis model.		[15,16,17,18,19]



[20]



[21,22]
Bifidobacterium adolescentisEPSBaEPSBa induces IL-10 production, protects from colitis by activation of DCs and macrophages, and increases the Treg/Th17 cell ratio in mice.[23]
Bifidobacterium breve UCC2003EPSBbEPSBb reduces Citrobacter rodentium infection in mice.
EPSBb prevents the maturation of DCs and activation of antigen-specific CD4+ T cells.
EPSBb reduces the rate of small epithelial cell shedding in a mouse model of pathological cell shedding.		[24]


[25]

[26]
Bifidobacterium breve WBBR04EPSBbEPSBb enhances the intestinal barrier integrity to prevent allergen infiltration and food allergy in mice.[27]
Bifidobacterium longumSerpinSerpin inhibits eukaryotic elastase-like serine proteases, which are dysregulated in inflammatory disorders.[28,29]
Bifidobacterium Longum 35624EPSBlEPSBl dampens pro-inflammatory cytokines and reduces inflammatory symptoms in a T cell transfer colitis model.
EPSBl stimulates the release of IL-10 in a TLR2-dependent manner and reduces eosinophil recruitment in the lungs in a respiratory inflammation mouse model.		[30]


[31]
Bifidobacterium Longum YS108REPSBlEPSBl reduces the pro-inflammatory cytokines IL-6 and IL-17A, alleviating inflammation in a colitis murine model.[32]
Bifidobacterium sp.FimbriaeFimbriae facilitate gut colonization and stimulation of macrophage cytokine production, TNF-α, IL-6, and Il-10.[33,34,35]
Escherichia coli Nissle 1917FlagellinFlagellin induces the release of β-defensin-2 in epithelial cells through NF-κB- and AP-1-dependent pathways in vitro.[36]
Lactobacillus acidophilus NCFMSurface layer protein A (SlpA)SlpA binds the lectin-receptor DC-SIGN and increases IL-10 and reduces IL-12p70 production from DCs.[37]
Lactobacillus caseiLactoceptinLactoceptin can selectively hydrolyze pro-inflammatory chemokine IP-10 leading to reduced lymphocyte recruitment in an ileitis murine model.[38]
Lactobacillus casei BL23p40 and p75Secreted proteins p40 and p75 stimulate Akt activation, display anti-apoptotic activity, and prevent epithelial barrier damage in colitis murine models.[39,40,41]
Lactobacillus casei ShirotaHigh molecular components of cell wall

Polysaccharide peptidoglycan complex		High molecular weight cell wall components of Lactobacillus casei Shirota decrease LPS-induced IL-6 production in macrophages.
Polysaccharide peptidoglycan complex improves ileitis and inhibits IL6/STAT3 signaling in a murine colitis model.		[42]



[43]
Lactobacillus helveticus KLD1.8701EPSLhEPSLh reduces intestinal inflammation and improves mucosal barrier function in a murine colitis model.[44]
Lactobacillus kefiranofaciensEPSLkEPSLk increases the number of IgA+ cells in the small and large intestines and increases the levels of IL-4 and IL-12 in the intestinal fluid and serum.[45]
Lactobacillus plantarumSerine-threonine peptide (STp)STp changes the phenotype of DC from ulcerative colitis patients by reducing TLR expression, increasing activation markers, and restoring stimulatory capacity.[46]
Lactobacillus plantarumLTALTA from L. plantarum and Staphylococcus aureus alleviates atopic dermatitis by regulating the complement regulatory proteins CD55 and CD59 and reducing activation of the complement system.
LTA inhibits the release of TNF-α and IL-10 from stimulated THP-1 cells by dephosphorylating c-Jun N-terminal kinase (JNK) and p38, respectively.		[47]




[48]
Lactobacillus plantarum K8LTALTA suppresses inflammatory cytokine-mediated complement activation through the inhibition of C3 synthesis.[49]
Lactobacillus plantarum L-14EPSLpEPSLp suppresses the pro-inflammatory cytokine mediators, COX-2, IL-6, TNF-α, and IL-1β induced by LPS.[50]
Lactobacillus plantarum N-14EPSLpEPSLp activates RP105/MD1 on intestinal epithelial cells to reduce inflammatory pathways.[51]
Lactobacillus rhamnosus GGPiliPili helps the adhesion of Lactobacillus rhamnosus GG to epithelial and the release of anti-inflammatory IL-10, IL-8, and IL-6 from epithelial cells.[34,52]
Lactobacillus rhamnosus GGLipoteichoic acid (LTA)
Supernatants		LTA improves colitis in a murine model.
Administration of culture supernatants reduces eosinophil numbers, goblet cells, and lung inflammation in murine allergy model.		[53,54]
Lactobacillus sakeiLTALTA inhibits the secretion of TNF-α from UVA-exposed derma fibroblasts.[55]
Lactobacillus salivarius Ls33PeptidoglycanPeptidoglycan protects mice from chemically induced colitis in a NOD2-IL-10-dependent manner.[56]
Lactobacillus SpTeichonic acidsTeichonic acid induces IL-10 in a TLR2-dependent manner in macrophages.[57]
Lactobacillus paraplantarum BGCG11EPSLpEPSLp reduces pro-inflammatory cytokines in a hyperalgesia rat model that results in anti-hyperalgesic and anti-edematous outcomes.[58]
Lactobacillus plantarum NCU116EPSLpEPSLp regulates the tight junction proteins occluding and ZO-1 by activating STAT3.[59]
Lactobacillus rhamnosus GGEPSLr



LTA		EPSLr reduces hydrogen peroxide-induced intestinal oxidative damage and apoptosis by Keap1/Nrf2 and Bax/Bcl-2 pathways in vitro.
LTA protects intestinal epithelial cells from radiation injury through the activation of pericryptal macrophages. These macrophages release CXCL12 that binds to CXCR4 on COX-2 expressing mesenchymal stem cells and stimulate the release of PGE, which protects epithelial stem cells from radiation.		[60]



[61]
Lactobacillus rhamnosus KL37EPSLrEPSLr inhibits T cell-dependent immune response reducing the arthritogenic antibodies in an arthritis murine model.[62]
Propionibacterium freudenreichiiGuanidine surface protein extractTreatment of human peripheral blood with guanidine surface protein extract releases IL-10 and IL-6, while having no effect on IL-12, TNF-α, and IFNγ.[63]
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Zamora-Pineda, J.; Kalinina, O.; Osborne, B.A.; Knight, K.L. Probiotic Molecules That Inhibit Inflammatory Diseases. Appl. Sci. 2022, 12, 1147. https://doi.org/10.3390/app12031147

AMA Style

Zamora-Pineda J, Kalinina O, Osborne BA, Knight KL. Probiotic Molecules That Inhibit Inflammatory Diseases. Applied Sciences. 2022; 12(3):1147. https://doi.org/10.3390/app12031147

Chicago/Turabian Style

Zamora-Pineda, Jesus, Olga Kalinina, Barbara A. Osborne, and Katherine L. Knight. 2022. "Probiotic Molecules That Inhibit Inflammatory Diseases" Applied Sciences 12, no. 3: 1147. https://doi.org/10.3390/app12031147

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop