Search Results (34)

The interaction between immune regulatory cells, such as regulatory B cells (Breg) and pro-resolving macrophages (M2 macrophages), plays an important role in the restoration of immune homeostasis during inflammation. PD-L1 is one of the effector molecules that mediates the immune regulation function of M2 macrophages. The activation of PD-L1/PD-1 signaling promotes the differentiation of Breg. Previous studies have shown that Breg promoted M2 macrophage polarization and enhanced their function, but little is known about the regulatory function of M2 macrophages on Breg differentiation. This study aims to determine the effect of M2 macrophages on Breg induction and the potential mechanism in vitro. Bone-marrow-derived macrophages were isolated from wild-type (WT) mice and polarized into M2 using IL-4/IL-13. To investigate the role of PD-L1/PD-1 in M2 macrophage-induced Breg differentiation, spleen B cells were isolated from WT or PD-1 knockout (KO) mice and co-cultured with either naïve (M0) or M2 macrophages for 48 h with or without trans-well inserts. The expression of IL-10, IL-35, and TGF-β1 in B cells was evaluated by flow cytometry and immunofluorescence staining. Recombinant PD-L1 was used to stimulate activated B cells, followed by the detection of IL-35 and TGF-β1. The results show that there was no significant difference in IL-10 expression among all groups. However, IL-35 and TGF-β1 expression in B cells was significantly increased in the M2+B, but not in M0+B, compared to B cells alone. Notably, such increases were diminished when M2 and B cells were separated by trans-well inserts. IL-35 expression was not significantly changed when B cells from PD-1 KO mice were co-cultured with M2 compared to the control. However, TGF-β1 expression was significantly increased when PD-1 KO B cells were co-cultured with M2 compared to the control. IL-35 expression in activated B cells was increased upon stimulation with PD-L1. However, TGF-β1 expression in activated B cells was increased regardless of the PD-L1 availability. This study demonstrates that pro-resolving macrophage-induced IL-35⁺ but not TGF-β1⁺ regulatory B cell activation requires the PD-L1/PD-1 pathway. Full article

In response to vaccination and/or infectious agents, the liver produces acute-phase proteins (APPs) driven by IL-6, which circulate in blood plasma as components of the humoral innate defense. This study investigates the liver of mice for possible effects of protective vaccination against primary blood-stage infections of Plasmodium chabaudi malaria on the expression of genes encoding APPs and IL-6 family members. Female Balb/c mice were vaccinated with a non-infectious vaccine prior to challenge with 10⁶ P. chabaudi-infected erythrocytes, resulting in about 80% survival of otherwise lethal infections. Gene expression microarrays were used to determine the relative transcript levels of genes in the livers of vaccinated and unvaccinated mice on days 0, 1, 4, 8, and 11 p.i. (post infectionem). Vaccination induced significant (p-value < 0.05) differences in the expression of malaria-responsive genes toward the end of crisis on day 11 p.i., when mice recovered from infections. These genes include Saa4, Apcs, Cp, and Crp, encoding APPs described to inhibitorily interact with parasitic blood stages; the genes F2, F7, F8, F9, F10, and F13b, and Plg, Plat, and Serpina5, encoding proteins balancing coagulation vs. fibrinolysis dysregulated by malaria, respectively; the genes Hc, C8a, C8b, C8g, and C9, encoding components of lytic complement membrane attack complex (MAC); and Cfh, Cfi, and C4bp, encoding complement-regulatory proteins. Vaccination accelerated, albeit differently, the malaria-induced activation of all three complement pathways, evidenced as higher transcript levels of C1qa, C1qb, C1qc, Fcna, Cfp, C3, Cfh, C8a, and C9 on day 4 p.i., C1ra, C1s, and C2 on day 1 p.i., and Serping1, encoding the multifunctional protease inhibitor C1INH, on day 0 p.i. Protective vaccination may also accelerate downregulation of the malaria-promoting lethality of IL-6 trans-signaling, which may contribute to an overall accelerated recovery of mice from otherwise lethal blood-stage malaria. Full article

Background/Objectives: Charcot first described ALS in 1869, but the specific mechanisms that mediate the disease pathology are still not clear. Intense research efforts have provided insight into unique neuroanatomical regions, specific neuronal populations and genetic associations for ALS and other neurodegenerative diseases; however, the experimental results also suggest a convergence of these events to common toxic pathways. We propose that common toxic pathways can be therapeutically targeted, and this intervention will be effective in slowing progression and improving patient quality of life. Here, we focus on understanding the role of IL6 trans-signaling in ALS disease processes. Methods: We leveraged unique mouse models of IL6 trans-signaling that we developed that recapitulate the production of active sIL6R in a genotypic and quantitative fashion observed in humans. Given that the SOD1 transgenic mouse is one of the most highly studied and characterized models of ALS, we bred SOD1^G93A mice with IL6R trans-signaling mice to determine how enhanced trans-signaling influenced symptom onset and pathological processes, including neuromuscular junction (NMJ) denervation, glial activation and motoneuron (MN) survival. Results: The results indicate that in animals with enhanced trans-signaling, symptom onset and pathological processes were accelerated, suggesting a role in disease modification. Administration of an IL6R functional blocking antibody failed to alter accelerated symptom onset and disease progression. Conclusions: Future work to investigate the site-specific influence of enhanced IL6 trans-signaling and the tissue-specific bioavailability of potential therapeutics will be necessary to identify targets for precise therapeutic interventions that may limit disease progression in the 60% of ALS patients who inherit the common Il6R Asp³⁵⁸Ala variant. Full article

Medulloblastoma (MB) is the most common malignant brain tumor in children, typically arising during infancy and childhood. Despite multimodal therapies achieving a response rate of 70% in children older than 3 years, treatment remains challenging. Ferroptosis, a form of regulated cell death, can be induced in medulloblastoma cells in vitro using erastin or RSL3. Using two independent medulloblastoma RNA-sequencing cohorts (MB-PBTA and MTAB-10767), we investigated the expression of ferroptosis-related molecules through multiple approaches, including Weighted Gene Co-Expression Network Analysis (WGCNA), molecular subtype stratification, protein–protein interaction (PPI) networks, and univariable and multivariable overall survival analyses. A prognostic expression score was computed based on a cross-validated ferroptosis signature. In training and validation cohorts, the regulation of the ferroptosis transcriptional program distinguished the four molecular subtypes of medulloblastoma. WGCNA identified nine gene modules in the MB tumor transcriptome; five correlated with molecular subtypes, implicating pathways related to oxidative stress, hypoxia, and trans-synaptic signaling. One module, associated with disease recurrence, included epigenetic regulators and nucleosome organizers. Univariable survival analyses identified a 45-gene ferroptosis prognostic signature associated with nutrient sensing, cysteine and methionine metabolism, and trans-sulfuration within a one-carbon metabolism. The top ten unfavorable ferroptosis genes included CCT3, SNX5, SQOR, G3BP1, CARS1, SLC39A14, FAM98A, FXR1, TFAP2C, and ATF4. Patients with a high ferroptosis score showed a worse prognosis, particularly in the G3 and SHH subtypes. The PPI network highlighted IL6 and CBS as unfavorable hub genes. In a multivariable overall survival model, which included gender, age, and the molecular subtype classification, the ferroptosis expression score was validated as an independent adverse prognostic marker (hazard ratio: 5.8; p-value = 1.04 × 10⁻⁹). This study demonstrates that the regulation of the ferroptosis transcriptional program is linked to medulloblastoma molecular subtypes and patient prognosis. A cross-validated ferroptosis signature was identified in two independent RNA-sequencing cohorts, and the ferroptosis score was confirmed as an independent and adverse prognostic factor in medulloblastoma. Full article

IL-6 remains a key molecule of the cytokine storms characterizing COVID-19, exerting both proinflammatory and anti-inflammatory effects. Emerging research underscores the significance of IL-6 trans-signaling over classical signaling pathways, which has shifted the focus of therapeutic strategies. Additionally, the synergistic action of TNF-α and IFN-γ has been found to induce inflammatory cell death through PANoptosis, further amplifying the severity of cytokine storms. Long COVID-19 patients, as well as those with cytokine storms triggered by other conditions, exhibit distinct laboratory profiles, indicating the need for targeted approaches to diagnosis and management. Growing evidence also highlights the gut microbiota’s crucial role in modulating the immune response during COVID-19 by affecting cytokine production, adding further complexity to the disease’s immunological landscape. Targeted intervention strategies should focus on specific cytokine cutoffs, though accurate cytokine quantification remains a clinical challenge. Current treatment strategies are increasingly focused on inhibiting IL-6 trans-signaling, which offers promise for more precise therapeutic approaches to manage hyperinflammatory responses in COVID-19. In light of recent discoveries, this review summarizes key research findings on cytokine storms, particularly their role in COVID-19 and other inflammatory conditions. It explores emerging therapeutic strategies targeting cytokines like IL-6, TNF-α, and IFN-γ, while also addressing open questions, such as the need for better biomarkers to detect and manage cytokine storms. Additionally, the review highlights ongoing challenges in developing targeted treatments that mitigate hyperinflammation without compromising immune function, emphasizing the importance of continued research in this field. Full article

Inflammation with expression of interleukin 6 (IL-6) in the central nervous system (CNS) occurs in several neurodegenerative/neuroinflammatory conditions and may cause neurochemical changes to endogenous neuroprotective systems. Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) are two neuropeptides with well-established protective and anti-inflammatory properties. Yet, whether PACAP and VIP levels are altered in mice with CNS-restricted, astrocyte-targeted production of IL-6 (GFAP-IL6) remains unknown. In this study, PACAP/VIP levels were assessed in the brain of GFAP-IL6 mice. In addition, we utilised bi-genic GFAP-IL6 mice carrying the human sgp130-Fc transgene (termed GFAP-IL6/sgp130Fc mice) to determine whether trans-signalling inhibition rescued PACAP/VIP changes in the CNS. Transcripts and protein levels of PACAP and VIP, as well as their receptors PAC1, VPAC1 and VPAC2, were significantly increased in the cerebrum and cerebellum of GFAP-IL6 mice vs. wild type (WT) littermates. These results were paralleled by a robust activation of the JAK/STAT3, NF-κB and ERK1/2MAPK pathways in GFAP-IL6 mice. In contrast, co-expression of sgp130Fc in GFAP-IL6/sgp130Fc mice reduced VIP expression and activation of STAT3 and NF-κB pathways, but it failed to rescue PACAP, PACAP/VIP receptors and Erk1/2MAPK phosphorylation. We conclude that forced expression of IL-6 in astrocytes induces the activation of the PACAP/VIP neuropeptide system in the brain, which is only partly modulated upon IL-6 trans-signalling inhibition. Increased expression of PACAP/VIP neuropeptides and receptors may represent a homeostatic response of the CNS to an uncontrolled IL-6 synthesis and its neuroinflammatory consequences. Full article

Acute myeloid leukemia (AML) is characterized by the abnormal proliferation and differentiation arrest of myeloid progenitor cells. The clinical treatment of AML remains challenging. Promoting AML cell differentiation is a valid strategy, but effective differentiation drugs are lacking for most types of AML. In this study, we generated Tg(drl:hoxa9) zebrafish, in which hoxa9 overexpression was driven in hematopoietic cells and myeloid differentiation arrest was exhibited. Using Tg(drl:hoxa9) embryos, we performed chemical screening and identified four FDA-approved drugs, ethacrynic acid, khellin, oxcarbazepine, and alendronate, that efficiently restored myeloid differentiation. The four drugs also induced AML cell differentiation, with ethacrynic acid being the most effective. By an RNA-seq analysis, we found that during differentiation, ethacrynic acid activated the IL-17 and MAPK signaling pathways, which are known to promote granulopoiesis. Furthermore, we found that ethacrynic acid enhanced all-trans retinoic acid (ATRA)-induced differentiation, and both types of signaling converged on the IL-17/MAPK pathways. Inhibiting the IL-17/MAPK pathways impaired ethacrynic acid and ATRA-induced differentiation. In addition, we showed that ethacrynic acid is less toxic to embryogenesis and less disruptive to normal hematopoiesis than ATRA. Thus, the combination of ethacrynic acid and ATRA may have broader clinical applications. In conclusion, through zebrafish-aided screening, our study identified four drugs that can be repurposed to induce AML differentiation, thus providing new agents for AML therapy. Full article

In late December 2019, SARS-CoV-2 was identified as the cause of a new pneumonia (COVID-19), leading to a global pandemic declared by the WHO on 11 March 2020, with significant human, economic, and social costs. Although most COVID-19 cases are asymptomatic or mild, 14% progress to severe disease, and 5% develop critical illness with complications such as interstitial pneumonia, acute respiratory distress syndrome (ARDS), and multiple organ dysfunction syndrome (MODS). SARS-CoV-2 primarily targets the respiratory system but can affect multiple organs due to the widespread presence of angiotensin-converting enzyme 2 (ACE2) receptors, which the virus uses to enter cells. This broad distribution of ACE2 receptors means that SARS-CoV-2 infection can lead to cardiovascular, gastrointestinal, renal, hepatic, central nervous system, and ocular damage. The virus triggers the innate and adaptive immune systems, resulting in a massive cytokine release, known as a “cytokine storm”, which is linked to tissue damage and poor outcomes in severe lung disease. Interleukin-6 (IL-6) is particularly important in this cytokine release, with elevated levels serving as a marker of severe COVID-19. IL-6 is a multifunctional cytokine with both anti-inflammatory and pro-inflammatory properties, acting through two main pathways: classical signalling and trans-signalling. Classical signalling involves IL-6 binding to its membrane-bound receptor IL-6R and then to the gp130 protein, while trans-signalling occurs when IL-6 binds to the soluble form of IL-6R (sIL-6R) and then to membrane-bound gp130 on cells that do not express IL-6R. The soluble form of gp130 (sgp130) can inhibit IL-6 trans-signalling by binding to sIL-6R, thereby preventing it from interacting with membrane-bound gp130. Given the central role of IL-6 in COVID-19 inflammation and its association with severe disease, we aimed to analyse the behaviour of IL-6 and its soluble receptor complex during different waves of the pandemic. This analysis could help determine whether IL-6 levels can serve as prognostic markers of disease severity. Full article

Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma. The oncogene product Tax of HTLV-I is thought to play crucial roles in leukemogenesis by promoting proliferation of the virus-infected cells through activation of growth-promoting genes. These genes code for growth factors and their receptors, cytokines, cell adhesion molecules, growth signal transducers, transcription factors and cell cycle regulators. We show here that Tax activates the gene coding for coactivator-associated arginine methyltransferase 1 (CARM1), which epigenetically enhances gene expression through methylation of histones. Tax activated the Carm1 gene and increased protein expression, not only in human T-cell lines but also in normal peripheral blood lymphocytes (PHA-PBLs). Tax increased R17-methylated histone H3 on the target gene IL-2Rα, concomitant with increased expression of CARM1. Short hairpin RNA (shRNA)-mediated knockdown of CARM1 decreased Tax-mediated induction of IL-2Rα and Cyclin D2 gene expression, reduced E2F activation and inhibited cell cycle progression. Tax acted via response elements in intron 1 of the Carm1 gene, through the NF-κB pathway. These results suggest that Tax-mediated activation of the Carm1 gene contributes to leukemogenic target-gene expression and cell cycle progression, identifying the first epigenetic target gene for Tax-mediated trans-activation in cell growth promotion. Full article

HLA-DR-positive NK cells, found in both healthy individuals and patients with different inflammatory diseases, are characterized as activated cells. However, data on their capacity for IFNγ production or cytotoxic response vary between studies. Thus, more precise investigation is needed of the mechanisms related to the induction of HLA-DR expression in NK cells, their associations with NK cell differentiation stage, and functional or metabolic state. In this work, HLA-DR-expressing NK cell subsets were investigated using transcriptomic analysis, metabolic activity assays, and analysis of intercellular signaling cascades. We demonstrated that HLA-DR⁺CD56^bright NK cells were characterized by a proliferative phenotype, while HLA-DR⁺CD56^dim NK cells exhibited features of adaptive cells and loss of inhibitory receptors with increased expression of MHC class II trans-activator CIITA. The activated state of HLA-DR-expressing NK cells was confirmed by higher levels of ATP and mitochondrial mass observed in this subset compared to HLA-DR⁻ cells, both ex vivo and after stimulation in culture. We showed that HLA-DR expression in NK cells in vitro can be induced both through stimulation by exogenous IL-2 and IL-21, as well as through auto-stimulation by NK-cell-produced IFNγ. At the intracellular level, HLA-DR expression depended on the activation of STAT3- and ERK1/2-mediated pathways, with subsequent activation of isoform 3 of the transcription factor CIITA. The obtained results broaden the knowledge about HLA-DR-positive NK cell appearance, diversity, and functions, which might be useful in terms of understanding the role of this subset in innate immunity and assessing their possible implications in NK cell-based therapy. Full article

Alzheimer’s disease (AD) is known as the primary and most common cause of dementia in the middle-aged and elderly population worldwide. Chemical analyses of B. pendula leaf extract (BPE), performed using spectrophotometric and chromatographic methods (LC/MS), revealed high amounts of polyphenol carboxylic acids (gallic, chlorogenic, caffeic, trans-p-coumaric, ferulic, and salicylic acids), as well as flavonoids (apigenin, luteolin, luteolin-7-O-glucoside, naringenin, hyperoside, quercetin, and quercitrin). Four groups of Wistar rats were used in this experiment (n = 7/group): control (untreated), Aβ_1-42 (2 μg/rat intracerebroventricular (i.c.v.), Aβ_1-42 + BPE (200 mg/Kg b.w.), and DMSO (10 μL/rat). On the first day, one dose of Aβ_1-42 was intracerebroventricularly administered to animals in groups 2 and 3. Subsequently, BPE was orally administered for the next 15 days to group 3. On the 16th day, behavioral tests were performed. Biomarkers of brain oxidative stress Malondialdehyde (MDA), (Peroxidase (PRx), Catalase (CAT), and Superoxid dismutase (SOD) and inflammation (cytokines: tumor necrosis factor -α (TNF-α), Interleukin 1β (IL-1β), and cyclooxygenase-2 (COX 2)) in plasma and hippocampus homogenates were assessed. Various protein expressions (Phospho-Tau (Ser404) (pTau Ser 404), Phospho-Tau (Ser396) (pTau Ser 396), synaptophysin, and the Nuclear factor kappa B (NFkB) signaling pathway) were analyzed using Western blot and immunohistochemistry in the hippocampus. The results show that BPE diminished lipid peroxidation and neuroinflammation, modulated specific protein expression, enhanced the antioxidant capacity, and improved spontaneous alternation behavior, suggesting that it has beneficial effects in AD. Full article

Zelkova schneideriana is a fast-growing tree species endemic to China. Recent surveys and reports have highlighted a continued decline in its natural populations; therefore, it is included in the Red List of Threatened Species by The International Union for Conservation of Nature. A new variety “HenTianGao” (H) has been developed with smaller plant height, slow growth, and lower branching points. In this study, we attempted to understand the differences in plant height of Z. schneideriana (J) and its dwarf variety H. We determined the endogenous hormone content in the annual grafted branches of both J and H. J exhibited higher gibberellic acid (GA)-19 and trans-Zeatin (tZ) levels, whereas H had higher levels of indole-3-acetic acid (IAA) catabolite 2-oxindole-3-acetic acid (OxIAA), IAA-Glu conjugate, and jasmonic acid (JA) (and its conjugate JA-Ile). The transcriptome comparison showed differential regulation of 20,944 genes enriched in growth and development, signaling, and metabolism-related pathways. The results show that the differential phytohormone level (IAA, JA, tZ, and GA) was consistent with the expression of the genes associated with their biosynthesis. The differences in relative OxIAA, IAA-Glu, GA19, trans-Zeatin, JA, and JA-Ile levels were linked to changes in respective signaling-related genes. We also observed significant differences in the expression of cell size, number, proliferation, cell wall biosynthesis, and remodeling-related genes in J and H. The differences in relative endogenous hormone levels, expression of biosynthesis, and signaling genes provide a theoretical basis for understanding the plant height differences in Z. schneideriana. Full article

We investigated the IL-6 receptor (IL-6R) expression on the surface of T cells isolated from peripheral blood mononuclear cells (PBMCs) of microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) patients and measured the serum soluble IL-6R (sIL-6R) levels in these patients. Sera and PBMCs were obtained from 51 patients with MPA (n = 32) and GPA (n = 19), with 25 patients having active disease (defined as a Birmingham Vasculitis Activity Score [BVAS] ≥ 5). The median age of patients was 67.0 years, and 52.9% were women. Serum IL-6 levels were significantly correlated with the BVAS (r = 0.384); however, IL-6R expression on the surface of T cells did not significantly differ based on disease activity. Meanwhile, IL-6R expression on the surface of stimulated CD4+ (median mean fluorescence intensity [MFI] 588.0 vs. 1314.8; p < 0.001), CD4+CD25+ (MFI 853.3 vs. 1527.3; p < 0.001), and CD4+CD45RO+ (MFI 679.5 vs. 1241.5; p < 0.001) T cells was significantly reduced compared with unstimulated conditions. Conversely, patients with active disease exhibited a significantly higher median serum sIL-6R level than those with inactive disease (38.1 ng/mL vs. 34.7 ng/mL; p = 0.029). These results imply that the trans-signalling IL-6 pathway may be more activated than the classical signalling pathway in patients with MPA and GPA, suggesting the therapeutic potential of targeting sIL-6R. Full article

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by significant fibrosis of the skin and internal organs, with the main involvement of the lungs, kidneys, heart, esophagus, and intestines. SSc is also characterized by macro- and microvascular damage with reduced peripheral blood perfusion. Several studies have reported more than 240 pathways and numerous dysregulation proteins, giving insight into how the field of biomarkers in SSc is still extremely complex and evolving. Antinuclear antibodies (ANA) are present in more than 90% of SSc patients, and anti-centromere and anti-topoisomerase I antibodies are considered classic biomarkers with precise clinical features. Recent studies have reported that trans-forming growth factor β (TGF-β) plays a central role in the fibrotic process. In addition, interferon regulatory factor 5 (IRF5), interleukin receptor-associated kinase-1 (IRAK-1), connective tissue growth factor (CTGF), transducer and activator of transcription signal 4 (STAT4), pyrin-containing domain 1 (NLRP1), as well as genetic factors, including DRB1 alleles, are implicated in SSc damage. Several interleukins (e.g., IL-1, IL-6, IL-10, IL-17, IL-22, and IL-35) and chemokines (e.g., CCL 2, 5, 23, and CXC 9, 10, 16) are elevated in SSc. While adiponectin and maresin 1 are reduced in patients with SSc, biomarkers are important in research but will be increasingly so in the diagnosis and therapeutic approach to SSc. This review aims to present and highlight the various biomarker molecules, pathways, and receptors involved in the pathology of SSc. Full article

Perilipin 5 (PLIN5) is a lipid droplet coat protein that is highly expressed in oxidative tissues such as those of muscles, the heart and the liver. PLIN5 expression is regulated by a family of peroxisome proliferator-activated receptors (PPARs) and modulated by the cellular lipid status. So far, research has focused on the role of PLIN5 in the context of non-alcoholic fatty liver disease (NAFLD) and specifically in lipid droplet formation and lipolysis, where PLIN5 serves as a regulator of lipid metabolism. In addition, there are only limited studies connecting PLIN5 to hepatocellular carcinoma (HCC), where PLIN5 expression is proven to be upregulated in hepatic tissue. Considering that HCC development is highly driven by cytokines present throughout NAFLD development and in the tumor microenvironment, we here explore the possible regulation of PLIN5 by cytokines known to be involved in HCC and NAFLD progression. We demonstrate that PLIN5 expression is strongly induced by interleukin-6 (IL-6) in a dose- and time-dependent manner in Hep3B cells. Moreover, IL-6-dependent PLIN5 upregulation is mediated by the JAK/STAT3 signaling pathway, which can be blocked by transforming growth factor-β (TGF-β) and tumor necrosis factor-α (TNF-α). Furthermore, IL-6-mediated PLIN5 upregulation changes when IL-6 trans-signaling is stimulated through the addition of soluble IL-6R. In sum, this study sheds light on lipid-independent regulation of PLIN5 expression in the liver, making PLIN5 a crucial target for NAFLD-induced HCC. Full article