Next Article in Journal
An Experimental Murine Model to Assess Biofilm Persistence on Commercial Breast Implant Surfaces
Previous Article in Journal
Proteomic Study of Response to Copper, Cadmium, and Chrome Ion Stress in Yarrowia lipolytica Strains Isolated from Andean Mine Tailings in Peru
Previous Article in Special Issue
Regulation of Immune Homeostasis via Muramyl Peptides-Low Molecular Weight Bioregulators of Bacterial Origin
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Microorganisms
Volume 10
Issue 10
10.3390/microorganisms10102003
microorganisms-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
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Brucella Phagocytosis Mediated by Pathogen-Host Interactions and Their Intracellular Survival

by
Tran X. N. Huy
1,2,
Trang T. Nguyen
1,
Heejin Kim
1,
Alisha W. B. Reyes
3 and
Suk Kim
1,*
1
Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea
2
Institute of Applied Sciences, HUTECH University, 475A Dien Bien Phu St., Ward 25, Binh Thanh District, Ho Chi Minh City 72300, Vietnam
3
Department of Veterinary Paraclinical Sciences, College of Veterinary Medicine, University of the Philippines Los Baños, Laguna 4031, Philippines
*
Author to whom correspondence should be addressed.
Microorganisms 2022, 10(10), 2003; https://doi.org/10.3390/microorganisms10102003
Submission received: 15 August 2022 / Revised: 8 October 2022 / Accepted: 8 October 2022 / Published: 11 October 2022
(This article belongs to the Special Issue Host–Microbe Interactions in Animal/Human Health and Disease 2021)
Browse Figures
Review Reports Versions Notes

Abstract

:
The Brucella species is the causative agent of brucellosis in humans and animals. So far, brucellosis has caused considerable economic losses and serious public health threats. Furthermore, Brucella is classified as a category B bioterrorism agent. Although the mortality of brucellosis is low, the pathogens are persistent in mammalian hosts and result in chronic infection. Brucella is a facultative intracellular bacterium; hence, it has to invade different professional and non-professional phagocytes through the host phagocytosis mechanism to establish its lifecycle. The phagocytosis of Brucella into the host cells undergoes several phases including Brucella detection, formation of Brucella-containing vacuoles, and Brucella survival via intracellular growth or being killed by host-specific bactericidal activities. Different host surface receptors contribute effectively to recognize Brucella including non-opsonic receptors (toll-like receptors and scavenger receptor A) or opsonic receptors (Fc receptors and complement system receptors). Brucella lacks classical virulence factors such as exotoxin, spores, cytolysins, exoenzymes, virulence plasmid, and capsules. However, once internalized, Brucella expresses various virulence factors to avoid phagolysosome fusion, bypass harsh environments, and establish a replicative niche. This review provides general and updated information regarding Brucella phagocytosis mediated by pathogen-host interactions and their intracellular survival in host cells.

1. Introduction

Brucellosis is a globally distributed major bacterial zoonosis characterized by abortion and reproductive failure in livestock, which seriously affects the development of animal husbandry and international trade. Although the mortality rate is low, it is harmful to human health as it can lead to a debilitating disease and serious chronic complications if left untreated [1,2,3]. The transmission of infection to humans is primarily via direct contact with animals, handling of contaminated tissues, and consumption of unpasteurized milk [1]. Furthermore, the Brucella species is classified as a category B bioterrorism agent due to its ease of transmission via aerosol [4].
No licensed human vaccine is available against brucellosis, and despite harsh therapy using a combination of two antibiotics for several weeks to months, relapses or clinical failures still occur [5,6]. Consequently, the control of human brucellosis depends on the control of brucellosis in livestock, which cannot primarily rely on vaccination alone but must be tackled in combination with proper husbandry measures [6,7]. Additionally, the widely used live attenuated Brucella vaccines for animals, such as Brucella (B.) abortus S19 and B. melitensis Rev. 1, both induce abortions, are virulent for humans, and interfere with serodiagnosis. Furthermore, Rev. 1 is resistant to streptomycin, which is a necessary antibiotic used for the treatment of the disease, and B. abortus RB51 still presents residual virulence [6,8].
The causative agent, Brucella species, is a Gram-negative facultative intracellular bacterium. Among Brucella species, three of them are known to be endemic in most countries and are highly virulent to both their natural hosts and to humans, including B. abortus, B. melitensis and B. suis that primarily infect cattle, sheep and goats, and domestic feral and wild swine populations, respectively [4,9]. Brucella lacks well-known or classical virulence factors such as spores, fimbriae, cytolysins, exotoxins, secreted proteases, antigenic variation, resistance forms, phage-encoded toxins, virulence plasmids, and capsules [7,10]. The virulence factors that have been reported to be necessary for invasion, the establishment of infection, as well as intracellular survival and replication of Brucella are cyclic β-1,2-glucan (CβG), VirB T4SS, pathogen-associated molecular patterns, two-component sensory and regulatory system BvrS/BvrR, and lipopolysaccharide (LPS) [2,7]. Brucella LPS is altered, so it is a weak inducer of the host inflammatory response compared to LPS molecules of other Gram-negative bacteria [9,11]. Other virulence factors include outer membrane proteins, BacA, SagA, BmaC, BetB, BtaE, MucR, and a genomic island associated with Brucella pathogenicity [7].
Brucella can infect both professional phagocytes such as macrophages and dendritic cells (DCs), and non-professional phagocytes such as placental trophoblasts and epithelial cells [6,11]. Other cells can also be infected by Brucella, such as neutrophils, lymphocytes, and erythrocytes, although no efficient intracellular replication is attributed as they are more associated with bacterial dispersion hence providing an indication of their regulatory role in the persistence of the bacteria [1]. Due to its capacity to survive and replicate within host macrophages, the Brucella pathogen has the ability to produce chronic infection that could lead to life-long infections. Dendritic cells (DCs) are well-known antigen presenting cells, which are also considered a safe haven for Brucella growth. Brucella can interfere with their maturation leading to the inhibition of antigen processing and presentation that circumvents the host immune response. Moreover, Brucella can infect the animal placenta resulting in abortion. In particular, it can replicate in the placental trophoblasts, where erythritol is produced. Indeed, the erythritol utilization is one of Brucella’s virulence factors [11]. Four steps are essential for Brucella to infect the host: adherence, internalization, intracellular growth, and dissemination within the host [7]. This review mainly focuses on the phagocytosis of Brucella spp. into the host cells as well as its intracellular growth in the macrophage cell model, on which there is currently still minimal information available to completely describe Brucella’s interaction with its target cells and tissues.

2. Brucella Phagocytosis and Intracellular Survival

2.1. Pathogen Recognition

2.1.1. Bacterial Adhesion

As mentioned earlier, Brucella possesses the ability to cause chronic infection in many different cell types. Brucella must break the epithelial barriers to cause systemic infection. To do that, the bacteria first have to invade the host cells to initiate their intracellular infectious cycle. Therefore, adhesion to the host cells is the first and most essential step in the invasion process. Brucella expresses various adhesin molecules to mediate the host and pathogen interaction. Brucella adhesins include the sialic acid-binding proteins SP29 and SP41; BigA and BigB proteins containing the immunoglobulin-like domain; the monomeric autotransporters BmaA, BmaB, and BmaC; the trimeric autotransporters BtaE and BtaF; and collagen, vitronectin-binding protein Bp26. These molecules regulate Brucella adhesion to host cell surface molecules and extracellular matrix components. In addition to ensuring the adhesion of Brucella to the host cell surface, these adhesins are considered immunogens or vaccine candidates to activate host immunity [12,13,14,15,16,17]. A study by Castaneda-Roldan et al. [16] displayed that a Brucella surface protein SP41 can bind selectively to epithelial HeLa cells. This adhesin protein is the expressed product of the ugpB gene. Brucella ugpB knockout strain decreased bacterial internalization by 40- to 50-fold less than the wild-type strain. Besides, another surface protein with an apparent molecular mass of 29-kDa was demonstrated to target the host gangliosides structure on red blood cells. A fraction of SP29 was found as a periplasmic protein in B. melitensis [18]. A region in chromosome 1 of B. abortus contains a gene, bigA, which codes an adhesin. This adhesin mediates the adherence and invasion into Madin-Darby canine kidney (MDCK) and Caco-2 cells. By performing immunofluorescence microscopy and Western blot assay, this adhesin was proven to localize at the outer membrane and contain an immunoglobulin-like domain, respectively [19]. It is noteworthy that VirB5 is an effector of a well-known Brucella virulence factor T4SS that plays an essential role in Brucella infection and is also recognized as an adhesin to contact with the host cells. Indeed, Deng et al. [20] determined that a single domain antibody, BaV5VH4, can bind Brucella VirB5 protein, disrupting the interaction between Brucella and host macrophage cells. Though the VirB5 protein in Agrobacterium tumefaciens localizes to the T-pilus tip that contributes to host-cell recognition, its direct adhesion function in this bacterium or Brucella is still unclear and needs to be deeply clarified [21].

2.1.2. Host Receptors

Once Brucella adheres to host cells, the binding of the pathogen to various host cell receptors activates a series of signaling pathways essential for bacterial uptake. Opsonized bacteria are internalized via complement receptors (CRs) and Fc receptors (FcRs) which promote the efficient phagocytosis of Brucella into host phagocytes. A major virulence factor of Brucella, the LPS O-chain fragment, is responsible for binding to antibodies or the C3 component of complement systems [22,23,24]. Opsonization of Brucella enhances the uptake of Brucella into human monocytes [25]. Eze et al. [22] reported that antibody and complement-mediated opsonization resulted in a profound increase in the phagocytosis of B. melitensis in murine peritoneal macrophages in individual or synergistic effects. However, another study by Rittig et al. [26] showed that the opsonization of Brucella by antibody but not complement contributed to increasing the uptake of Brucella in human monocytes. These authors proposed a reason that complement receptor 3 (CR3) has both opsonic and non-opsonic binding sites. Thus, Brucella can bind directly to this receptor without the need for the main opsonic complement fragment iC3b [26,27,28]. Although the opsonic entry plays an essential role in the early stage of Brucella infection, studies have reported that the contribution of FcRs and CRs in the phagocytosis of Brucella are still limited. Among FcRs, FCγRIIA plays a crucial role in the phagocytosis of IgG2-opsonized bacteria. Hosseini khah et al. [29] proved that FCγRIIA (CD32) and the polymorphism of this receptor are associated with susceptibility to brucellosis in humans. The most efficient phagocytic receptor among CRs is CR3 (integrin, Mac-1) [28,30].
On the other hand, host cell receptors classified as lectin and fibronectin receptors recognize non-opsonized bacteria. Scavenger receptor A (SR-A) is a well-described lectin receptor in recognition of Brucella. This receptor can effectively detect lipid A fraction of LPS [31]. Interestingly, following Brucella internalization by SR-A recognition, T4SS is considered a regulator for SR-A signal transduction that enables Brucella to establish an intracellular lifecycle in the host cells [31,32].
Among host receptors that recognize Brucella, toll-like receptors (TLRs) are most characterized for their functions in recognition and immune response against brucellosis [33]. Much experimental evidence suggests the essential role of TLRs in phagocytosis and in the host signaling pathways to protect against Brucella infection. TLR2, TLR4, and TLR6 are supposed to recognize different membrane components of Brucella, while TLR3, TLR7, and TLR9 have been found accountable for the detection of Brucella nucleic acid structure motifs [34,35,36,37,38]. Although TLRs contribute to the host protection against Brucella infection, these pathogens may interfere with TLRs-mediated immune signaling to evade recognition by the innate immune system. A TIR domain-containing protein in Brucella (TcpB) interferes with MAL-TLR4 interaction leading to the inhibition of TLR4 signaling pathway. Particularly, the DD loop of TB-8 and TB-9, which are TcpB-derived decoy peptides, is supposed to be able to specifically bind to the MAL TIR domain to form a dimer, then disrupt MAL TIR domain-mediated interaction leading to the inhibition of TLR4 signaling. This interference prevents DCs maturation and the cytotoxic activity of cytotoxic T lymphocytes during Brucella chronic infection [39,40,41]. TLR2 recognizes Brucella lipoprotein, but it has been revealed to have no function in controlling Brucella infection in the TLR2 knockout mice model [42,43]. TLR4 can recognize LPS, and a non-canonical lipid A of LPS at a very high concentration resulting in the promotion of the maturation phagocytic vacuoles and inducing the pro-inflammatory cytokine TNF-α [44]. Regarding receptor costimulation, Brucella can express more than one ligand for various host cell receptors. Heat-killed B. abortus simultaneously costimulates TLR2 and TLR9 in mouse DCs. This costimulation ensures bacterial phagocytosis and promotes the downstream signal transduction of these receptors [45]. In addition, TLR2 also plays a critical role in Brucella invasion into trophoblast giant cells [46]. This suggests that Brucella can infect different types of cells in the same way.

2.2. Engulfment and Internalization Process Activation

2.2.1. Bacterial Engulfment

Upon translocation across the mucosal epithelial cell layer, professional phagocytes such as macrophages, DCs, and macrophage-like cells engulf the bacteria in which <10% of these phagocytosed Brucella survive and escape killing during the initial phase of infection. Following the binding of Brucella, phagocytic and non-phagocytic receptors mediate a variety of signaling pathways, leading to the remodeling of the cell membrane structure to engulf bacteria [6,8]. Generally, Brucella induces a zipper-like mechanism for internalization [47]. Up to 8 min after contact, Brucella moves in a swimming motion on the cell surface with a generalized membrane ruffling. At the same time, the cell surface is rearranged and actin polymerization is activated around the side of bacterial adherence. Notably, these events depend on the Brucella virulence factor VirB [48,49]. Moreover, the cellular prion protein (PrPc) is a glycoprotein anchored on the outer leaflet of the plasma membrane. It is associated with phagocytosis via cytoskeletal rearrangement and the host inflammatory response. The PrPc is described as a major internalization receptor on M cells during Brucella via the oral route [50,51,52]. However, the role of PrPc in Brucella internalization is still controversial. Indeed, upon B. melitensis infection, silencing of PrPc in microglia cells did not affect bacterial phagocytosis and intracellular killing [53].
Actin polymerization is required in the penetration of Brucella into host cells. Bacterial adhesion to cell surface involves other proteins acting as second messengers including cGMP, PIP3-kinase, MAP-kinase, and tyrosine kinase that leads to activation of GTPases of Rho subfamilies such as Rho, Rac, and Cdc42, which play a critical role in the regulation of the cytoskeleton [8,54]. Additionally, a genome-wide small interfering RNA perturbation screen was performed to identify novel host factors crucial for Brucella intracellular trafficking. The results displayed that the prominently affected clusters are related to actin-remodeling and phagocytosis. These clusters include ARP2/3, WASP regulatory complex, and the small GTPases Rac1 and Cdc42 [55]. Consistently, adhesion to the macrophage surface involves the activation of GTPases and F-actin polymerization where, at the early stage of infection, annexin I is also implicated in membrane fusion [8,49,54]. Besides, adhesin protein BigA was proven to induce actin-cytoskeleton rearrangement in MDCK and Caco-2 cell lines [19]. The TLR4/PI3-kinase signaling pathway is essential for smooth Brucella strain internalization but not in the rough strain. The smooth strain infection quickly elicits F-actin polymerization at the early stage of infection and fuses the early endosome faster than the rough strain [56].

2.2.2. Formation and Maturation of Brucella-Containing Vacuoles

Internalization occurs via lipid raft microdomains at the macrophage cell membrane that are rich in cholesterol, glycosylphosphatidylinositol, and gangliosides, and contribute to the intracellular trafficking of Brucella [8,52]. Following interaction with the cell membrane of professional or non-professional phagocytes and around 5 min after entry, BCVs enter the endocytic pathway, initiated by the fusion with early endosome, characterized by Rab5, early endosomal antigen 1, and the transferrin receptor (TfR) markers [57,58]. At the next stage of internalization, BCVs continue to fuse with the late endosomes that undergo transient acidification, leading to changes in bacterial gene expression and intracellular survival associated with the late endosomal markers Rab7, RILP, and Lamp1 during 4 h post-infection (pi) [55,59,60]. The presence or absence of these lysosomal markers in the BCVs maturation can be used to evaluate the effect of Brucella virulence factors on its intracellular survival. Brucella expresses various effector molecules to modulate its intracellular trafficking. For example, Brucella can secrete a lysozyme-like protein SagA identified as a muramidase. This enzyme participates in the early stage of Brucella intracellular trafficking by avoiding BCVs and lysosome fusion. In particular, it regulates the recruitment of Lamp1 in the BCVs maturation by an unknown mechanism [61]. In addition, Brucella membrane fusogenic protein interacts with phospholipid vesicles to favor membrane fusion and is involved in the recruitment of lysosomal markers, Lamp1 [62]. However, the specific mechanism in this event is still unclear [63]. A study by Naroeni et al. [64] revealed that live B. suis prevented the fusion of B. suis-containing phagosomes with the lysosome compartment while this association was clearly observed using killed B. suis.
The interaction between BCVs and endoplasmic reticulum (ER) from 4 to 8 h pi results in the formation of replicative BCVs (rBCVs) with the presence of several ER markers such as calnexin, calreticulin, and Sec61β [60]. It is noteworthy that interaction between lipid rafts and O-chain of smooth Brucella LPS plays a vital role in the mediation of the bacterial entry that leads to the development of specialized membrane-bound compartments known as replicative phagosomes or replicative vacuoles [65]. The continuity of rBCV membranes with the ER was observed unmistakably by applying the 3D-CLEM approach. This study proposed a model where rBCVs are integrated into the ER meshwork [66]. On the other hand, CβG is well-known as a virulence factor of Brucella sp. and can modulate lipid raft organization. CβG probably acts on lipid raft to favor the recruitment of lipid raft marker flotillin-1 from 0.5 to 8 h pi. In addition, CβG regulates the lysosome fusion and enables BCVs to associate with ER [67,68].

2.3. Host Intracellular Killing or Bacterial Intracellular Growth

2.3.1. Host Bactericidal Effect against Brucella

Following bacterial engulfment by host cells, most ingested Brucella that are localized in the endosomal BCVs (eBCVs) are killed within the phagolysosome compartment in the last stage of phagosome maturation during 4 to 8 h pi. Using a fluorescent probe specifically for proteolytic activity, during the first 6 h pi, the BCVs clearly showed fluorescent intensity emission, and this remarkable fluorescence was not detected at 12 h pi [69]. The phagolysosome compartment displays many effectors that limit Brucella growth and survival such as reactive oxygen species (ROS), nitric oxide (NO), and antimicrobial peptides [70,71]. Nitric oxide and lysozyme activities are employed to monitor RB51 vaccine efficiency in cows [72]. This is because NO can react with structural elements, metabolic enzymes, nucleic acid, and it inhibits bacterial secretion system expression. A study by Hu et al. [73] indicated that thioredoxin-interacting protein (TXNIP), a multifunctional protein in metabolic diseases, is involved in the production of NO and ROS, leading to the control of bacyccterial intracellular survival. These authors proposed a novel host pathway, iNOS/NO-TXNIP-iNOS/NO, related to Brucella T4SS expression. Aside from NO, although ROS causes DNA, protein, and lipid damage, Brucella possesses xthA-1 gene that encodes a protein that contributes to oxidative stress resistance [74]. On the other hand, rough Brucella induces monocytes to secrete higher CXC, CC chemokines (GRO-α, IL-8, MCP-1α, MCP-1β, MCP-1, and RANTES), pro-inflammatory (IL-6, TNF-α), and anti-inflammatory (IL-10) cytokines than the smooth strain [75]. The lacking of the O-chain of LPS interferes with the fusion between the BCVs and lysosomes [76]. Therefore, the decrease in bacterial viability is more dramatic with strains that are lacking in the O-chain of LPS.

2.3.2. Brucella Intracellular Survival

In the early stage of phagocytosis, a small proportion of BCVs allows Brucella to start proliferating. Some evidence for this event include the inhibition of Rab7 recruitment, which is essential for phagolysosome fusion, and the acidification of this compartment, which triggers the expression of T4SS. Besides, Brucella chromosomal replication was observed at 8 h pi within Lamp1-positive BCVs [77]. Up-to-date studies revealed that effectors of T4SS have crucial roles in inhibiting host immune responses and promoting intracellular trafficking and growth during Brucella infection. In particular, RicA can interact with Rab2 GTPase, which is critical for Brucella intracellular trafficking [60]. VceC and VecA are related to host autophagy and apoptosis. BtpA and BtpB are required to modulate host immunity and energy metabolism. In addition, other T4SS effectors also play different roles in the host-Brucella interaction that have been extensively studied, clarifying their specific functions [78,79,80]. A study by Martinez-Nunez et al. [81] demonstrated that BvrS/R transcriptionally regulates T4SS VirB. A bvrS and bvrR mutant resulted in low levels of the VirB1, VirB5, VirB8, and VirB9. In addition, this study clarified that the regulator protein BvrR binds directly to the VirB promoter. The BvrR/BvrS system is one of the virulence factors that interacts with other diverse virulence factors simultaneously to ensure the intracellular growth fate of Brucella.
Brucella can start multiplying in macrophages at 12 to 24 h pi [69]. At this time, two events are in progress. First, the pathogen readily reaches its safe haven to replicate. Lastly, the pathogen has set up its specific virulence genes. The conversion from eBCVs to rBCVs is a hallmark of Brucella intracellular growth. In addition to the beneficial functions of T4SS in promoting Brucella intracellular replication, a study by Casanova et al. [55] discovered two components of the trimeric vacuolar protein sorting complex, VPS35 and VPS26A, which are related to the evasion of the lysosomal degradative pathway. In this infection stage, Brucella is in a multi-membranous compartment, supplemented with several autophagosomal bodies and ER markers. The association of Brucella with the host ER establishes the replicative niche. By reaching this organelle, Brucella can take advantage of the biosynthetic enzymes, connect to the local nutrient supply, and avoid phagolysosome fusion [76,77,82]. On the other hand, Kohler et al. [76] proposed the term “brucellosome” for the replicative niche of Brucella, which is poor in nutrients, low in oxygen tension, and with a neutral pH microenvironment. However, Brucella still furtively exploits these harsh environments as stimuli to induce virulence genes involved in their intracellular trafficking and growth [83]. Once adapted to the intramacrophage environment, Brucella extends its intracellular persistence indefinitely, contributing to systemic proliferation and dissemination to other targeted cells or tissues. Furthermore, at this late stage of infection, the switch from rBCVs to the autophagic BCVs (aBCVs) mediates bacterial release from infected cells. Autophagy-initiation proteins ULK1, Beclin 1, ATG14L and PI3-kinase activity is required for the aBCVs formation. This event is exploited by Brucella for cell-to-cell spreading [84,85,86]. However, once again, Brucella continues displaying an effector of the T4SS system, BspL, to delay the formation of aBCVs that benefit the optimal intracellular replication before disseminating to other cells. At the same time, BspJ, a nucleomodulin, directly or indirectly regulates host cell apoptosis to complete its intracellular cycle [87,88]. As mentioned, the microenvironment inside these vacuoles has limited nutrients. Interestingly, Brucella behaves as a stealthy pathogen. It has adapted to these harsh intracellular environments in the host cells by setting up various virulence factors such as the heat shock proteins DnaK and ClpB. These virulent factors play an important role in Brucella resistance against some stresses but do not favor intracellular growth [89].

3. Conclusions

Brucella sp. is a facultative intracellular pathogen. It can infect professional and non-professional phagocytes. To establish its intracellular niche, it has to invade host cells, initiated by bacterial adherence to the host cell surface. The detection of Brucella by various host cell receptors is the second phase of bacterial phagocytosis (Figure 1). Once Brucella is detected by either opsonic or non-opsonic receptors, various signaling pathways are activated to engulf and uptake it into the host cells. In the typical way of phagocytosis, BCVs enter the endosomal pathway from the fusion steps with early endosomes, late endosomes, and lysosomes resulting in bacterial elimination. Nevertheless, as a stealthy pathogen, Brucella facilitates its intracellular replication by exploiting host cell resources. More than that, Brucella has various effectors that interfere with antibacterial mechanisms to ensure its intracellular survival (Figure 2). Furthermore, all Brucella functional proteins related to the interaction between Brucella and host cells is summarized in Table 1.
Brucellosis is a worldwide disease causing severe economic and public health problems. Therefore, understanding the characteristics of the causative agent, its interaction with host cells and specific virulence factors is vital in eradicating brucellosis. Several recent studies focus on understanding the interaction between Brucella and its host, and the mechanism of how it works, but still the available data are limited and the complete mechanisms involved are unclear. In fact, in comparison to other bacteria such as Mycobacterium species, Salmonella species, and Helicobacterium species, more research has been recently invested in Brucella species. However, there are still many gaps in understanding Brucella phagocytosis, and many questions remain unanswered particularly regarding the interaction between molecules related to F-actin polymerization including cofilin, profilin, ARP2/3, and WASP that renders importance in the context of Brucella infection. In addition, searching for more virulence factors implicated during Brucella phagocytosis also deserves more attention. Therefore, more extensive efforts are necessary to study this stealthy pathogen deeper in order to discover alternative therapies or even more effective vaccines to eliminate brucellosis completely.

Author Contributions

T.X.N.H., T.T.N., H.K. and A.W.B.R.: Writing—original draft. A.W.B.R., T.X.N.H.: Writing—review & editing. S.K.: Conceptualization, Resources. S.K.: Funding acquisition, Writing—review & editing, Project administration. All authors have read and agreed to the published version of the manuscript.

Funding

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2018R1D1A3B05048283).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

Abbreviations

CβGCyclic β-1,2-glucan
LPSLipopolysaccharide
DCsDendritic cells
MDCKMadin-Darby canine kidney
CRsComplement receptors
FcRsFc receptors
CR3Complement receptor 3
SR-AScavenger receptor A
TLRsToll-like receptors
TcpBA TIR domain-containing protein in Brucella
PrPcThe cellular prion protein
TfRTransferrin receptor
EREndoplasmic reticulum
rBCVsReplicative BCVs
eBCVsEndosomal BCVs
ROSReactive oxygen species
NONitric oxide
aBCVsAutophagic BCVs

References

  1. Gonzalez-Espinoza, G.; Arce-Gorvel, V.; Memet, S.; Gorvel, J.P. Brucella: Reservoirs and Niches in Animals and Humans. Pathogens 2021, 10, 186. [Google Scholar] [CrossRef] [PubMed]
  2. Jiao, H.; Zhou, Z.; Li, B.; Xiao, Y.; Li, M.; Zeng, H.; Guo, X.; Gu, G. The Mechanism of Facultative Intracellular Parasitism of Brucella. Int. J. Mol. Sci. 2021, 22, 3673. [Google Scholar] [CrossRef] [PubMed]
  3. Aliyev, J.; Alakbarova, M.; Garayusifova, A.; Omarov, A.; Aliyeva, S.; Fretin, D.; Godfroid, J. Identification and Molecular Characterization of Brucella abortus and Brucella melitensis Isolated from Milk in Cattle in Azerbaijan. BMC Vet. Res. 2022, 18, 71. [Google Scholar] [CrossRef]
  4. Laine, C.G.; Scott, H.M.; Arenas-Gamboa, A.M. Human Brucellosis: Widespread Information Deficiency Hinders an Understanding of Global Disease Frequency. PLoS Negl. Trop. Dis. 2022, 16, E0010404. [Google Scholar] [CrossRef]
  5. Solis Garcia Del Pozo, J.; Solera, J. Systematic Review and Meta-Analysis of Randomized Clinical Trials in The Treatment of Human Brucellosis. PLoS ONE 2012, 7, E32090. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  6. Lalsiamthara, J.; Lee, J.H. Development and Trial of Vaccines Against Brucella. J. Vet. Sci. 2017, 18, 281–290. [Google Scholar] [CrossRef]
  7. Dadar, M.; Tiwari, R.; Sharun, K.; Dhama, K. Importance of Brucellosis Control Programs of Livestock on The Improvement of One Health. Vet. Q. 2021, 41, 137–151. [Google Scholar] [CrossRef] [PubMed]
  8. Glowacka, P.; Zakowska, D.; Naylor, K.; Niemcewicz, M.; Bielawska-Drozd, A. Brucella—Virulence Factors, Pathogenesis and Treatment. Pol. J. Microbiol. 2018, 67, 151–161. [Google Scholar] [CrossRef] [Green Version]
  9. Gheitasi, R.; Keramat, F.; Khosravi, S.; Hajilooi, M.; Pletz, M.W.; Makarewicz, O. Evaluation of Th2 and Th17 Immunity-Related Factors As Indicators of Brucellosis. Front. Cell. Infect. Microbiol. 2021, 11, 786994. [Google Scholar] [CrossRef]
  10. He, Y. Analyses of Brucella Pathogenesis, Host Immunity, and Vaccine Targets Using Systems Biology and Bioinformatics. Front. Cell. Infect. Microbiol. 2012, 2, 2. [Google Scholar] [CrossRef] [PubMed]
  11. Roop, R.M., 2nd; Gaines, J.M.; Anderson, E.S.; Caswell, C.C.; Martin, D.W. Survival of The Fittest: How Brucella Strains Adapt to Their Intracellular Niche in The Host. Med. Microbiol. Immunol. 2009, 198, 221–238. [Google Scholar] [CrossRef] [Green Version]
  12. Bialer, M.G.; Sycz, G.; Munoz Gonzalez, F.; Ferrero, M.C.; Baldi, P.C.; Zorreguieta, A. Adhesins of Brucella: Their Roles in The Interaction with The Host. Pathogens 2020, 9, 942. [Google Scholar] [CrossRef]
  13. Munoz Gonzalez, F.; Sycz, G.; Alonso Paiva, I.M.; Linke, D.; Zorreguieta, A.; Baldi, P.C.; Ferrero, M.C. The Btaf Adhesin Is Necessary for Full Virulence during Respiratory Infection by Brucella suis and Is a Novel Immunogen for Nasal Vaccination Against Brucella Infection. Front. Immunol. 2019, 10, 1775. [Google Scholar] [CrossRef] [Green Version]
  14. Eltahir, Y.; Al-Araimi, A.; Nair, R.R.; Autio, K.J.; Tu, H.; Leo, J.C.; Al-Marzooqi, W.; Johnson, E.H. Binding of Brucella Protein, Bp26, to Select Extracellular Matrix Molecules. BMC Mol. Cell Biol. 2019, 20, 55. [Google Scholar] [CrossRef]
  15. Lopez, P.; Guaimas, F.; Czibener, C.; Ugalde, J.E. A Genomic Island in Brucella Involved in the Adhesion to Host Cells: Identification of a New Adhesin and a Translocation Factor. Cell. Microbiol. 2020, 22, E13245. [Google Scholar] [CrossRef] [PubMed]
  16. Castaneda-Roldan, E.I.; Ouahrani-Bettache, S.; Saldana, Z.; Avelino, F.; Rendon, M.A.; Dornand, J.; Giron, J.A. Characterization of Sp41, a Surface Protein of Brucella Associated with Adherence and Invasion of Host Epithelial Cells. Cell. Microbiol. 2006, 8, 1877–1887. [Google Scholar] [CrossRef]
  17. Ruiz-Ranwez, V.; Posadas, D.M.; Van Der Henst, C.; Estein, S.M.; Arocena, G.M.; Abdian, P.L.; Martin, F.A.; Sieira, R.; De Bolle, X.; Zorreguieta, A. Btae, An Adhesin That Belongs to the Trimeric Autotransporter Family, Is Required for Full Virulence and Defines a Specific Adhesive Pole of Brucella suis. Infect. Immun. 2013, 81, 996–1007. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  18. Rocha-Gracia, R.D.C.; Castañeda-Roldán, E.I.; Giono-Cerezo, S.; Girón, J.A. Brucella sp. Bind to Sialic Acid Residues on Human and Animal Red Blood Cells. Fems Microbiol. Lett. 2002, 213, 219–224. [Google Scholar] [CrossRef] [Green Version]
  19. Czibener, C.; Merwaiss, F.; Guaimas, F.; Del Giudice, M.G.; Serantes, D.A.; Spera, J.M.; Ugalde, J.E. Biga Is a Novel Adhesin of Brucella That Mediates Adhesion to Epithelial Cells. Cell. Microbiol. 2016, 18, 500–513. [Google Scholar] [CrossRef] [Green Version]
  20. Deng, H.; Zhou, J.; Gong, B.; Xiao, M.; Zhang, M.; Pang, Q.; Zhang, X.; Zhao, B.; Zhou, X. Screening and Identification of a Human Domain Antibody Against Brucella abortus Virb5. Acta Trop. 2019, 197, 105026. [Google Scholar] [CrossRef] [PubMed]
  21. Aly, K.A.; Baron, C. The Virb5 Protein Localizes to the T-Pilus Tips in Agrobacterium Tumefaciens. Microbiology 2007, 153, 3766–3775. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  22. Eze, M.O.; Yuan, L.; Crawford, R.M.; Paranavitana, C.M.; Hadfield, T.L.; Bhattacharjee, A.K.; Warren, R.L.; Hoover, D.L. Effects of Opsonization and Gamma Interferon on Growth of Brucella melitensis 16 m in Mouse Peritoneal Macrophages In Vitro. Infect. Immun. 2000, 68, 257–263. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  23. Ahmed, W.; Zheng, K.; Liu, Z.F. Establishment of Chronic Infection: Brucella’s Stealth Strategy. Front. Cell. Infect. Microbiol. 2016, 6, 30. [Google Scholar] [CrossRef] [Green Version]
  24. Lin, M.; Nielsen, K. Binding of the Brucella abortus Lipopolysaccharide O-Chain Fragment to a Monoclonal Antibody. Quantitative Analysis by Fluorescence Quenching and Polarization. J. Biol. Chem. 1997, 272, 2821–2827. [Google Scholar] [CrossRef] [PubMed]
  25. Bellaire, B.H.; Roop, R.M., 2nd; Cardelli, J.A. Opsonized Virulent Brucella abortus Replicates within Nonacidic, Endoplasmic Reticulum-Negative, Lamp-1-Positive Phagosomes in Human Monocytes. Infect. Immun. 2005, 73, 3702–3713. [Google Scholar] [CrossRef] [Green Version]
  26. Rittig, M.G.; Alvarez-Martinez, M.T.; Porte, F.; Liautard, J.P.; Rouot, B. Intracellular Survival of Brucella spp. in Human Monocytes Involves Conventional Uptake But Special Phagosomes. Infect. Immun. 2001, 69, 3995–4006. [Google Scholar] [CrossRef] [Green Version]
  27. Fernandez-Prada, C.M.; Nikolich, M.; Vemulapalli, R.; Sriranganathan, N.; Boyle, S.M.; Schurig, G.G.; Hadfield, T.L.; Hoover, D.L. Deletion of Wboa Enhances Activation of the Lectin Pathway of Complement in Brucella abortus and Brucella melitensis. Infect. Immun. 2001, 69, 4407–4416. [Google Scholar] [CrossRef] [Green Version]
  28. Le Cabec, V.; Carreno, S.; Moisand, A.; Bordier, C.; Maridonneau-Parini, I. Complement Receptor 3 (Cd11b/Cd18) Mediates Type I and Type Ii Phagocytosis during Nonopsonic and Opsonic Phagocytosis, Respectively. J. Immunol. 2002, 169, 2003–2009. [Google Scholar] [CrossRef] [Green Version]
  29. Hosseini Khah, Z.; Bahadori, Z.; Rafiei, A.; Hajilooi, M. Association of Fcγriia (Cd32) Polymorphism with Susceptibility to Brucellosis. Res. Mol. Med. 2014, 2, 17–22. [Google Scholar] [CrossRef] [Green Version]
  30. Bajic, G.; Yatime, L.; Sim, R.B.; Vorup-Jensen, T.; Andersen, G.R. Structural Insight on the Recognition of Surface-Bound Opsonins by the Integrin I Domain of Complement Receptor 3. Proc. Natl. Acad. Sci. USA 2013, 110, 16426–16431. [Google Scholar] [CrossRef]
  31. Kim, S.; Watarai, M.; Suzuki, H.; Makino, S.; Kodama, T.; Shirahata, T. Lipid Raft Microdomains Mediate Class a Scavenger Receptor-Dependent Infection of Brucella abortus. Microb. Pathog. 2004, 37, 11–19. [Google Scholar] [CrossRef]
  32. Martin-Martin, A.I.; Vizcaino, N.; Fernandez-Lago, L. Cholesterol, Ganglioside Gm1 and Class a Scavenger Receptor Contribute to Infection by Brucella ovis and Brucella canis in Murine Macrophages. Microbes Infect. 2010, 12, 246–251. [Google Scholar] [CrossRef]
  33. Pei, J.; Ding, X.; Fan, Y.; Rice-Ficht, A.; Ficht, T.A. Toll-Like Receptors Are Critical for Clearance of Brucella and Play Different Roles in Development of Adaptive Immunity Following Aerosol Challenge in Mice. Front. Cell. Infect. Microbiol. 2012, 2, 115. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  34. Campos, P.C.; Gomes, M.T.; Guimaraes, E.S.; Guimaraes, G.; Oliveira, S.C. Tlr7 and Tlr3 Sense Brucella abortus Rna to Induce Proinflammatory Cytokine Production But They Are Dispensable for Host Control of Infection. Front. Immunol. 2017, 8, 28. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  35. De Almeida, L.A.; Macedo, G.C.; Marinho, F.A.; Gomes, M.T.; Corsetti, P.P.; Silva, A.M.; Cassataro, J.; Giambartolomei, G.H.; Oliveira, S.C. Toll-Like Receptor 6 Plays An Important Role in Host Innate Resistance to Brucella abortus Infection in Mice. Infect. Immun. 2013, 81, 1654–1662. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  36. Gomes, M.T.; Campos, P.C.; Pereira Gde, S.; Bartholomeu, D.C.; Splitter, G.; Oliveira, S.C. Tlr9 Is Required for Mapk/Nf-Kappab Activation But Does Not Cooperate with Tlr2 Or Tlr6 to Induce Host Resistance to Brucella abortus. J. Leukoc. Biol. 2016, 99, 771–780. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  37. Lee, J.J.; Kim, D.H.; Kim, D.G.; Lee, H.J.; Min, W.; Rhee, M.H.; Cho, J.Y.; Watarai, M.; Kim, S. Toll-Like Receptor 4-Linked Janus Kinase 2 Signaling Contributes to Internalization of Brucella abortus by Macrophages. Infect. Immun. 2013, 81, 2448–2458. [Google Scholar] [CrossRef] [Green Version]
  38. Delpino, M.V.; Barrionuevo, P.; Macedo, G.C.; Oliveira, S.C.; Genaro, S.D.; Scian, R.; Miraglia, M.C.; Fossati, C.A.; Baldi, P.C.; Giambartolomei, G.H. Macrophage-Elicited Osteoclastogenesis in Response To Brucella abortus Infection Requires Tlr2/Myd88-Dependent Tnf-Alpha Production. J. Leukoc. Biol. 2012, 91, 285–298. [Google Scholar] [CrossRef]
  39. Alaidarous, M.; Ve, T.; Casey, L.W.; Valkov, E.; Ericsson, D.J.; Ullah, M.O.; Schembri, M.A.; Mansell, A.; Sweet, M.J.; Kobe, B. Mechanism of Bacterial Interference with Tlr4 Signaling by Brucella Toll/Interleukin-1 Receptor Domain-Containing Protein Tcpb. J. Biol. Chem. 2014, 289, 654–668. [Google Scholar] [CrossRef] [Green Version]
  40. Ke, Y.; Li, W.; Wang, Y.; Yang, M.; Guo, J.; Zhan, S.; Du, X.; Wang, Z.; Yang, M.; Li, J.; et al. Inhibition of Tlr4 Signaling by Brucella Tir-Containing Protein Tcpb-Derived Decoy Peptides. Int. J. Med. Microbiol. 2016, 306, 391–400. [Google Scholar] [CrossRef]
  41. Amjadi, O.; Rafiei, A.; Mardani, M.; Zafari, P.; Zarifian, A. A Review of the Immunopathogenesis of Brucellosis. Infect. Dis. 2019, 51, 321–333. [Google Scholar] [CrossRef]
  42. Campos, M.A.; Rosinha, G.M.; Almeida, I.C.; Salgueiro, X.S.; Jarvis, B.W.; Splitter, G.A.; Qureshi, N.; Bruna-Romero, O.; Gazzinelli, R.T.; Oliveira, S.C. Role of Toll-Like Receptor 4 in Induction of Cell-Mediated Immunity and Resistance to Brucella abortus Infection in Mice. Infect. Immun. 2004, 72, 176–186. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  43. Weiss, D.S.; Takeda, K.; Akira, S.; Zychlinsky, A.; Moreno, E. Myd88, But Not Toll-Like Receptors 4 and 2, Is Required for Efficient Clearance of Brucella abortus. Infect. Immun. 2005, 73, 5137–5143. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  44. Barquero-Calvo, E.; Chaves-Olarte, E.; Weiss, D.S.; Guzman-Verri, C.; Chacon-Diaz, C.; Rucavado, A.; Moriyon, I.; Moreno, E. Brucella abortus Uses a Stealthy Strategy to Avoid Activation of the Innate Immune System during the Onset of Infection. PLoS ONE 2007, 2, E631. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  45. Zhang, C.Y.; Bai, N.; Zhang, Z.H.; Liang, N.; Dong, L.; Xiang, R.; Liu, C.H. Tlr2 Signaling Subpathways Regulate Tlr9 Signaling for the Effective Induction of Il-12 Upon Stimulation by Heat-Killed Brucella abortus. Cell. Mol. Immunol. 2012, 9, 324–333. [Google Scholar] [CrossRef] [Green Version]
  46. Watanabe, K.; Shin, E.-K.; Hashino, M.; Tachibana, M.; Watarai, M. Toll-Like Receptor 2 and Class B Scavenger Receptor Type I Are Required for Bacterial Uptake by Trophoblast Giant Cells. Mol. Immunol. 2010, 47, 1989–1996. [Google Scholar] [CrossRef] [PubMed]
  47. De Figueiredo, P.; Ficht, T.A.; Rice-Ficht, A.; Rossetti, C.A.; Adams, L.G. Pathogenesis and Immunobiology of Brucellosis: Review of Brucella-Host Interactions. Am. J. Pathol. 2015, 185, 1505–1517. [Google Scholar] [CrossRef] [PubMed]
  48. Watarai, M.; Makino, S.I.; Fujii, Y.; Okamoto, K.; Shirahata, T. Modulation of Brucella-Induced Macropinocytosis by Lipid Rafts Mediates Intracellular Replication. Cell. Microbiol. 2002, 4, 341–355. [Google Scholar] [CrossRef]
  49. Kusumawati, A.; Cazevieille, C.; Porte, F.; Bettache, S.; Liautard, J.P.; Sri Widada, J. Early Events and Implication of F-Actin and Annexin I Associated Structures in the Phagocytic Uptake of Brucella suis by the J-774a.1 Murine Cell Line and Human Monocytes. Microb. Pathog. 2000, 28, 343–352. [Google Scholar] [CrossRef] [PubMed]
  50. De Almeida, C.J.; Chiarini, L.B.; Da Silva, J.P.; Pm, E.S.; Martins, M.A.; Linden, R. the Cellular Prion Protein Modulates Phagocytosis and Inflammatory Response. J. Leukoc. Biol. 2005, 77, 238–246. [Google Scholar] [CrossRef]
  51. Nakato, G.; Hase, K.; Suzuki, M.; Kimura, M.; Ato, M.; Hanazato, M.; Tobiume, M.; Horiuchi, M.; Atarashi, R.; Nishida, N.; et al. Cutting Edge: Brucella abortus Exploits a Cellular Prion Protein on Intestinal M Cells As An Invasive Receptor. J. Immunol. 2012, 189, 1540–1544. [Google Scholar] [CrossRef] [Green Version]
  52. Watarai, M. Interaction Between Brucella abortus and Cellular Prion Protein in Lipid Raft Microdomains. Microbes Infect. 2004, 6, 93–100. [Google Scholar] [CrossRef] [PubMed]
  53. Erdogan, S.; Duzguner, V.; Kucukgul, A.; Aslantas, O. Silencing of Prp C (Prion Protein) Expression Does Not Affect Brucella melitensis Infection in Human Derived Microglia Cells. Res. Vet. Sci. 2013, 95, 368–373. [Google Scholar] [CrossRef] [PubMed]
  54. Guzman-Verri, C.; Chaves-Olarte, E.; Von Eichel-Streiber, C.; Lopez-Goni, I.; Thelestam, M.; Arvidson, S.; Gorvel, J.P.; Moreno, E. Gtpases of the Rho Subfamily Are Required for Brucella abortus Internalization in Nonprofessional Phagocytes: Direct Activation of Cdc42. J. Biol. Chem. 2001, 276, 44435–44443. [Google Scholar] [CrossRef] [Green Version]
  55. Casanova, A.; Low, S.H.; Québatte, M.; Sedzicki, J.; Tschon, T.; Ketterer, M.; Smith, K.; Emmenlauer, M.; Ben-Tekaya, H.; Dehio, C. A Role for the Vps Retromer in Brucella Intracellular Replication Revealed by Genomewide Sirna Screening. Msphere 2019, 4, E00380-19. [Google Scholar] [CrossRef] [Green Version]
  56. Pei, J.; Turse, J.E.; Ficht, T.A. Evidence of Brucella abortus Ops Dictating Uptake and Restricting Nf-Kappab Activation in Murine Macrophages. Microbes Infect. 2008, 10, 582–590. [Google Scholar] [CrossRef] [Green Version]
  57. Pizarro-Cerdá, J.; Moreno, E.; Gorvel, J.-P. Invasion and Intracellular Trafficking of Brucella abortus in Nonphagocytic Cells. Microbes Infect. 2000, 2, 829–835. [Google Scholar] [CrossRef]
  58. Celli, J.; De Chastellier, C.; Franchini, D.M.; Pizarro-Cerda, J.; Moreno, E.; Gorvel, J.P. Brucella Evades Macrophage Killing Via Virb-Dependent Sustained Interactions with the Endoplasmic Reticulum. J. Exp. Med. 2003, 198, 545–556. [Google Scholar] [CrossRef]
  59. Carvalho Neta, A.V.; Mol, J.P.; Xavier, M.N.; Paixao, T.A.; Lage, A.P.; Santos, R.L. Pathogenesis of Bovine Brucellosis. Vet. J. 2010, 184, 146–155. [Google Scholar] [CrossRef] [PubMed]
  60. De Bolle, X.; Letesson, J.J.; Gorvel, J.P. Small Gtpases and Brucella Entry Into the Endoplasmic Reticulum. Biochem. Soc. Trans. 2012, 40, 1348–1352. [Google Scholar] [CrossRef] [PubMed]
  61. Del Giudice, M.G.; Ugalde, J.E.; Czibener, C. A Lysozyme-Like Protein in Brucella abortus Is Involved in the Early Stages of Intracellular Replication. Infect. Immun. 2013, 81, 956–964. [Google Scholar] [CrossRef] [Green Version]
  62. Carrica, M.D.C.; Craig, P.O.; Alonso, S.D.V.; Goldbaum, F.A.; Cravero, S.L. Brucella abortus Mfp: A Trimeric Coiled-Coil Protein with Membrane Fusogenic Activity. Biochemistry 2008, 47, 8165–8175. [Google Scholar] [CrossRef]
  63. De Souza Filho, J.A.; De Paulo Martins, V.; Campos, P.C.; Alves-Silva, J.; Santos, N.V.; De Oliveira, F.S.; Menezes, G.B.; Azevedo, V.; Cravero, S.L.; Oliveira, S.C. Mutant Brucella abortus Membrane Fusogenic Protein Induces Protection Against Challenge Infection in Mice. Infect. Immun. 2015, 83, 1458–1464. [Google Scholar] [CrossRef] [Green Version]
  64. Naroeni, A.; Jouy, N.; Ouahrani-Bettache, S.; Liautard, J.P.; Porte, F. Brucella suis-Impaired Specific Recognition of Phagosomes by Lysosomes Due to Phagosomal Membrane Modifications. Infect. Immun. 2001, 69, 486–493. [Google Scholar] [CrossRef] [Green Version]
  65. Porte, F.; Naroeni, A.; Ouahrani-Bettache, S.; Liautard, J.P. Role of the Brucella suis Lipopolysaccharide O Antigen in Phagosomal Genesis and in Inhibition of Phagosome-Lysosome Fusion in Murine Macrophages. Infect. Immun. 2003, 71, 1481–1490. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  66. Sedzicki, J.; Tschon, T.; Low, S.H.; Willemart, K.; Goldie, K.N.; Letesson, J.J.; Stahlberg, H.; Dehio, C. 3d Correlative Electron Microscopy Reveals Continuity of Brucella-Containing Vacuoles with the Endoplasmic Reticulum. J. Cell. Sci. 2018, 131, jcs210799. [Google Scholar] [CrossRef] [Green Version]
  67. Arellano-Reynoso, B.; Lapaque, N.; Salcedo, S.; Briones, G.; Ciocchini, A.E.; Ugalde, R.; Moreno, E.; Moriyon, I.; Gorvel, J.P. Cyclic Beta-1,2-Glucan Is a Brucella Virulence Factor Required for Intracellular Survival. Nat. Immunol. 2005, 6, 618–625. [Google Scholar] [CrossRef] [PubMed]
  68. Guidolin, L.S.; Morrone Seijo, S.M.; Guaimas, F.F.; Comerci, D.J.; Ciocchini, A.E. Interaction Network and Localization of Brucella abortus Membrane Proteins Involved in the Synthesis, Transport, and Succinylation of Cyclic Beta-1,2-Glucans. J. Bacteriol. 2015, 197, 1640–1648. [Google Scholar] [CrossRef] [Green Version]
  69. Starr, T.; Ng, T.W.; Wehrly, T.D.; Knodler, L.A.; Celli, J. Brucella Intracellular Replication Requires Trafficking through the Late Endosomal/Lysosomal Compartment. Traffic 2008, 9, 678–694. [Google Scholar] [CrossRef] [PubMed]
  70. Ko, J.; Gendron-Fitzpatrick, A.; Splitter, G.A. Susceptibility of Ifn Regulatory Factor-1 and Ifn Consensus Sequence Binding Protein-Deficient Mice to Brucellosis. J. Immunol. 2002, 168, 2433–2440. [Google Scholar] [CrossRef]
  71. Uribe-Querol, E.; Rosales, C. Control of Phagocytosis by Microbial Pathogens. Front. Immunol. 2017, 8, 1368. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  72. Ali, M.A.M.S.; Reda, R.S.; Rania, I. Nitric Oxide and Lysozyme Activities As Early Monitors of the Immune Response of Brucella abortus Rb51 Vaccinated Cows.
  73. Hu, H.; Tian, M.; Li, P.; Guan, X.; Lian, Z.; Yin, Y.; Shi, W.; Ding, C.; Yu, S. Brucella Infection Regulates Thioredoxin-Interacting Protein Expression to Facilitate Intracellular Survival by Reducing the Production of Nitric Oxide and Reactive Oxygen Species. J. Immunol. 2020, 204, 632–643. [Google Scholar] [CrossRef] [PubMed]
  74. Hornback, M.L.; Roop, R.M., 2nd. The Brucella abortus Xtha-1 Gene Product Participates in Base Excision Repair and Resistance to Oxidative Killing But Is Not Required for Wild-Type Virulence in the Mouse Model. J. Bacteriol. 2006, 188, 1295–1300. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  75. Rittig, M.G.; Kaufmann, A.; Robins, A.; Shaw, B.; Sprenger, H.; Gemsa, D.; Foulongne, V.; Rouot, B.; Dornand, J. Smooth and Rough Lipopolysaccharide Phenotypes of Brucella Induce Different Intracellular Trafficking and Cytokine/Chemokine Release in Human Monocytes. J. Leukoc. Biol. 2003, 74, 1045–1055. [Google Scholar] [CrossRef] [PubMed]
  76. Köhler, S.; Michaux-Charachon, S.; Porte, F.; Ramuz, M.; Liautard, J.-P. What Is the Nature of the Replicative Niche of a Stealthy Bug Named Brucella? Trends Microbiol. 2003, 11, 215–219. [Google Scholar] [CrossRef]
  77. Celli, J. The Intracellular Life Cycle of Brucella spp. Microbiol. Spectr. 2019, 7, 1–11. [Google Scholar] [CrossRef] [PubMed]
  78. Xiong, X.; Li, B.; Zhou, Z.; Gu, G.; Li, M.; Liu, J.; Jiao, H. The Virb System Plays a Crucial Role in Brucella Intracellular Infection. Int. J. Mol. Sci. 2021, 22, 13637. [Google Scholar] [CrossRef]
  79. Ke, Y.; Wang, Y.; Li, W.; Chen, Z. Type Iv Secretion System of Brucella spp. and Its Effectors. Front. Cell. Infect. Microbiol. 2015, 5, 72. [Google Scholar] [CrossRef] [Green Version]
  80. Coronas-Serna, J.M.; Louche, A.; Rodriguez-Escudero, M.; Roussin, M.; Imbert, P.R.C.; Rodriguez-Escudero, I.; Terradot, L.; Molina, M.; Gorvel, J.P.; Cid, V.J.; et al. The Tir-Domain Containing Effectors Btpa and Btpb from Brucella abortus Impact Nad Metabolism. PLoS Pathog. 2020, 16, E1007979. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  81. Martinez-Nunez, C.; Altamirano-Silva, P.; Alvarado-Guillen, F.; Moreno, E.; Guzman-Verri, C.; Chaves-Olarte, E. The Two-Component System Bvrr/Bvrs Regulates the Expression of the Type Iv Secretion System Virb in Brucella abortus. J. Bacteriol. 2010, 192, 5603–5608. [Google Scholar] [CrossRef] [PubMed]
  82. Gorvel, J.P.; Moreno, E. Brucella Intracellular Life: From Invasion to Intracellular Replication. Vet. Microbiol. 2002, 90, 281–297. [Google Scholar] [CrossRef]
  83. Köhler, S.; Foulongne, V.; Ouahrani-Bettache, S.; Bourg, G.; Teyssier, J.; Ramuz, M.; Liautard, J.-P. The Analysis of the Intramacrophagic Virulome of Brucella suis Deciphers the Environment Encountered by the Pathogen Inside the Macrophage Host Cell. Proc. Natl. Acad. Sci. USA 2002, 99, 15711–15716. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  84. Brumell, J.H. Brucella “Hitches a Ride” with Autophagy. Cell Host Microbe 2012, 11, 2–4. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  85. Starr, T.; Child, R.; Wehrly, T.D.; Hansen, B.; Hwang, S.; López-Otin, C.; Virgin, H.W.; Celli, J. Selective Subversion of Autophagy Complexes Facilitates Completion of the Brucella Intracellular Cycle. Cell Host Microbe 2012, 11, 33–45. [Google Scholar] [CrossRef] [Green Version]
  86. Hanwei, J.; Nie, X.; Zhu, H.; Li, B.; Pang, F.; Yang, X.; Cao, R.; Yang, X.; Zhu, S.; Peng, D. Mir-146b-5p Plays a Critical Role in the Regulation of Autophagy In∆ Per Brucella melitensis-Infected Raw264. 7 Cells. Biomed. Res. Int. 2020, 2020, 1953242. [Google Scholar] [CrossRef]
  87. Luizet, J.B.; Raymond, J.; Lacerda, T.L.S.; Barbieux, E.; Kambarev, S.; Bonici, M.; Lembo, F.; Willemart, K.; Borg, J.P.; Celli, J.; et al. The Brucella Effector Bspl Targets the Er-Associated Degradation (Erad) Pathway and Delays Bacterial Egress from Infected Cells. Proc. Natl. Acad. Sci. USA 2021, 118, e2105324118. [Google Scholar] [CrossRef]
  88. Ma, Z.; Li, R.; Hu, R.; Deng, X.; Xu, Y.; Zheng, W.; Yi, J.; Wang, Y.; Chen, C. Brucella abortus Bspj Is a Nucleomodulin That Inhibits Macrophage Apoptosis and Promotes Intracellular Survival of Brucella. Front. Microbiol. 2020, 11, 599205. [Google Scholar] [CrossRef]
  89. Köhler, S.; Porte, F.; Jubier-Maurin, V.; Ouahrani-Bettache, S.; Teyssier, J.; Liautard, J.-P. The Intramacrophagic Environment of Brucella suis and Bacterial Response. Vet. Microbiol. 2002, 90, 299–309. [Google Scholar] [CrossRef]
Microorganisms 10 02003 g001 550
Figure 1. Brucella adhesion and recognition. (A) Brucella expresses various adhesins such as SP29, SP41, BigA, BigB, BmaA, BmaB, BmaC, BtaE, BtaF, Bp26, and T4SS-VirB5. These adhesins enable Brucella to adhere to the host cell surface through the extracellular matrix component, including collagen, fibronectin, or sialic acid-binding protein. (B) Once tightly adhered to the cell surface, Brucella can be detected by binding to various cell receptors. FcγIIA receptor and CR3, opsonic receptors, recognize the O-chain fragment of Brucella LPS. Whereas non-opsonic receptors comprise SR-A and TLRs. SR-A recognizes lipid A LPS. TLR2, 4, 6 detect surface molecules of Brucella such as LPS and lipoprotein, while TLR3, 7, 9 are responsible for recognition of nucleic acid motifs.
Figure 1. Brucella adhesion and recognition. (A) Brucella expresses various adhesins such as SP29, SP41, BigA, BigB, BmaA, BmaB, BmaC, BtaE, BtaF, Bp26, and T4SS-VirB5. These adhesins enable Brucella to adhere to the host cell surface through the extracellular matrix component, including collagen, fibronectin, or sialic acid-binding protein. (B) Once tightly adhered to the cell surface, Brucella can be detected by binding to various cell receptors. FcγIIA receptor and CR3, opsonic receptors, recognize the O-chain fragment of Brucella LPS. Whereas non-opsonic receptors comprise SR-A and TLRs. SR-A recognizes lipid A LPS. TLR2, 4, 6 detect surface molecules of Brucella such as LPS and lipoprotein, while TLR3, 7, 9 are responsible for recognition of nucleic acid motifs.
Microorganisms 10 02003 g001
Microorganisms 10 02003 g002 550
Figure 2. Intracellular trafficking cycle of Brucella in host cells. After recognizing Brucella by different receptors, host cells activate the signaling pathway resulting in F-actin polymerization at the binding site with bacteria. Then the BCVs undergo fusion with early, late endosome, and finally lysosome. At the last phase of BCVs’ maturation, Brucella is killed by nitric oxide, ROS, and digestive enzymes that localize in the phagolysosome compartment. However, Brucella has the ability to avoid the phagolysosome fusion to reach its intracellular niche at ER. Brucella SagA protein is secreted to interfere with the interaction between BCVs and lysosomes. Once localizing in ER, Brucella can proliferate and mature into aBCVs. This aBCVs formation depends on distinct autophagy proteins including ULK1 and Beclin 1, which contribute to bacterial egress and the formation of infection foci resulting in dissemination to other cells and tissues. Besides, Brucella activates a T4SS-BspL effector to delay the formation of aBCVs, and ultimately reach maximum proliferation.
Figure 2. Intracellular trafficking cycle of Brucella in host cells. After recognizing Brucella by different receptors, host cells activate the signaling pathway resulting in F-actin polymerization at the binding site with bacteria. Then the BCVs undergo fusion with early, late endosome, and finally lysosome. At the last phase of BCVs’ maturation, Brucella is killed by nitric oxide, ROS, and digestive enzymes that localize in the phagolysosome compartment. However, Brucella has the ability to avoid the phagolysosome fusion to reach its intracellular niche at ER. Brucella SagA protein is secreted to interfere with the interaction between BCVs and lysosomes. Once localizing in ER, Brucella can proliferate and mature into aBCVs. This aBCVs formation depends on distinct autophagy proteins including ULK1 and Beclin 1, which contribute to bacterial egress and the formation of infection foci resulting in dissemination to other cells and tissues. Besides, Brucella activates a T4SS-BspL effector to delay the formation of aBCVs, and ultimately reach maximum proliferation.
Microorganisms 10 02003 g002
Table
Table 1. Brucella functional proteins in interaction with host cells.
Table 1. Brucella functional proteins in interaction with host cells.
Brucella ProteinsFunctions
Cyclic β-1,2-glucanImportant for circumventing host cell defenses, and modulate lipid raft organization
VirB T4SSMediating intracellular survival and circumventing host immune responses
SP29, SP41Sialic acid-binding proteins, in bacterial adherence
BigA, BigBProteins containing the immunoglobulin-like domain, in bacterial adherence
BmaA, BmaB, BmaCThe monomeric autotransporters, in bacterial adherence
BtaE, BtaFThe trimeric autotransporters, in bacterial adherence
Bp26Collagen, vitronectin-binding protein, in bacterial adherence
VirB5Effector of a well-known Brucella virulence factor T4SS, in bacterial adherence
SagAA lysozyme-like protein SagA identified as a muramidase
VceC, VecAT4SS, related to host autophagy and apoptosis
BtpA, BtpBModulate host immunity and energy metabolism
BvrS/RTranscriptionally regulates T4SS VirB
VPS35, VPS26ARelated to the evasion of the lysosomal degradative pathway
BspLDelay the formation of aBCVs that benefit the optimal intracellular replication before disseminating to other cells
BspJA nucleomodulin, directly or indirectly regulates host cell apoptosis to complete its intracellular cycle
DnaK, ClpBHeat shock proteins, role in bacterial resistance against stresses
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Huy, T.X.N.; Nguyen, T.T.; Kim, H.; Reyes, A.W.B.; Kim, S. Brucella Phagocytosis Mediated by Pathogen-Host Interactions and Their Intracellular Survival. Microorganisms 2022, 10, 2003. https://doi.org/10.3390/microorganisms10102003

AMA Style

Huy TXN, Nguyen TT, Kim H, Reyes AWB, Kim S. Brucella Phagocytosis Mediated by Pathogen-Host Interactions and Their Intracellular Survival. Microorganisms. 2022; 10(10):2003. https://doi.org/10.3390/microorganisms10102003

Chicago/Turabian Style

Huy, Tran X. N., Trang T. Nguyen, Heejin Kim, Alisha W. B. Reyes, and Suk Kim. 2022. "Brucella Phagocytosis Mediated by Pathogen-Host Interactions and Their Intracellular Survival" Microorganisms 10, no. 10: 2003. https://doi.org/10.3390/microorganisms10102003

APA Style

Huy, T. X. N., Nguyen, T. T., Kim, H., Reyes, A. W. B., & Kim, S. (2022). Brucella Phagocytosis Mediated by Pathogen-Host Interactions and Their Intracellular Survival. Microorganisms, 10(10), 2003. https://doi.org/10.3390/microorganisms10102003

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