The chemerin/CMKLR1 axis regulates intestinal graft-versus-host disease.

Gastrointestinal graft-versus-host disease (GvHD) is a major cause of mortality and morbidity following allogeneic bone marrow transplantation (allo-BMT). Chemerin is a chemotactic protein that recruits leukocytes to inflamed tissues by interacting with ChemR23/CMKLR1, a chemotactic receptor expressed by leukocytes, including macrophages. During acute GvHD, chemerin plasma levels were strongly increased in allo-BM-transplanted mice. The role of the chemerin/CMKLR1 axis in GvHD was investigated using Cmklr1-KO mice. WT mice transplanted with an allogeneic graft from Cmklr1-KO donors (t-KO) had worse survival and more severe GvHD. Histological analysis demonstrated that the gastrointestinal tract was the organ mostly affected by GvHD in t-KO mice. The severe colitis of t-KO mice was characterized by massive neutrophil infiltration and tissue damage associated with bacterial translocation and exacerbated inflammation. Similarly, Cmklr1-KO recipient mice showed increased intestinal pathology in both allogeneic transplant and dextran sulfate sodium-induced colitis. Notably, the adoptive transfer of WT monocytes into t-KO mice mitigated GvHD manifestations by decreasing gut inflammation and T cell activation. In patients, higher chemerin serum levels were predictive of GvHD development. Overall, these results suggest that CMKLR1/chemerin may be a protective pathway for the control of intestinal inflammation and tissue damage in GvHD.

Dysbiosis of Gut Microbiota Promotes Hepatocellular Carcinoma Progression by Regulating the Immune Response.

METHOD: This study included 74 Chinese male patients with HCC. They were divided into early (n = 19), intermediate (n = 37), and terminal (n = 18) groups, referred to as Barcelona Clinic Liver Cancer stage 0+A, B, and C+D, respectively. Paired fecal and plasma samples were collected. Microbial composition and profiles were analyzed by 16S rRNA gene sequencing. The levels of gut damage marker (regenerating islet-derived protein 3α (REG3α)) and microbial translocation markers (soluble CD14 (sCD14), lipopolysaccharide-binding protein (LBP), peptidoglycan recognition proteins (PGRPs)) were determined in plasma samples of patients by ELISA. Twenty plasma cytokine and chemokines were determined by Luminex. RESULTS: In early, intermediate, and terminal groups, the abundance of the Bifidobacteriaceae family decreased significantly (3.52%, 1.55%, and 0.56%, respectively, P = 0.003), while the abundance of the Enterococcaceae family increased significantly (1.6%, 2.9%, and 13.4%, respectively, P = 0.022). Levels of REG3α and sCD14 were markedly elevated only in the terminal group compared with the early (P = 0.025 and P = 0.048) and intermediate groups (P = 0.023 and P = 0.046). The level of LBP significantly increased in the intermediate (P = 0.035) and terminal (P = 0.025) groups compared with the early group. The PGRP levels were elevated only in the terminal group compared with the early group (P = 0.018). The ratio of Enterococcaceae to Bifidobacteriaceae was significantly associated with the levels of REG3α, LBP, sCD14, and PGRPs. With HCC progression, increased levels of inflammatory cytokines accompanied by a T cell-immunosuppressive response and microbial translocation were observed. CONCLUSION: Gut microbiota compositional and functional shift, together with elevated gut damage and microbial translocation, may promote HCC development by stimulating inflammatory response and suppressing T cell response.

Are Pattern Recognition Receptors Associated with Hepatocellular Carcinoma?

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the important causes of mortality due to malignancy. Toll-like receptors (TLRs) are very important in liver pathophysiology in terms of their roles in the innate immune system, such as the regulation of inflammation, wound healing, stimulation of adaptive immune responses, promotion of epithelial regeneration, and carcinogenesis. In this study, we planned to examine the role of TLR1 (rs4833095, rs5743551) and nucleotide-binding oligomerization domain (NOD2) (rs2066844, rs2066845, rs2066847) polymorphisms in the development of HCC and their effects on the clinical presentation of HCC patients. METHODS: Our study was designed prospectively. Cirrhotic and HCC patients who were followed up in our clinic between January 2015 and September 2018 were included in the study. Sex, age, cirrhosis etiology, Child-Pugh class, and MELD scores were recorded. TLR1 and NOD2 polymorphisms were studied by the PCR method. RESULTS: HCC developed in 88 (31.4%) of the 280 patients who were followed up, either during the recruitment phase of our study or during the follow-up. The mean follow-up time of our patient group was 17.04 ± 11.72 months, and the mean follow-up time of HCC patients was 12.09 ± 10.26 months. TLR1 (rs5743551) polymorphism was associated with HCC development (P = .003). TLR1 (rs5743551) and NOD2 (rs2066844) polymorphisms were associated with the development of spontaneous bacterial peritonitis (SBP) in the HCC patient group (P = .013 and P = .021, respectively). CONCLUSION: We think that increased bacterial translocation in cirrhotic patients may contribute to HCC development by causing chronic inflammation, especially in patients with TLR 1 (rs5743551) polymorphism.

Altered intestinal microflora and barrier injury in severe acute pancreatitis can be changed by zinc.

To investigate the effect of zinc (Zn) supplementation on intestinal microflora changes and bacterial translocation in rats with severe acute pancreatitis (SAP), the rats were divided into the sham surgery (SS), SAP, SS + Zn, and SAP + Zn groups. Saline (0.1 mL/100g) and 5% sodium taurocholate were injected into the pancreaticobiliary duct of the rats in the SS and SAP + Zn groups, respectively. Intraperitoneal injection of 5 mg/kg Zn was performed immediately after injecting saline or 5% sodium taurocholate into the rats in both groups. Serum amylase and Zn levels, plasma endogenous endotoxin, intestinal permeability, and the positive rate of intestinal bacterial translocation were detected, haematoxylin and eosin (H&E) staining was performed, and the pancreatic tissue scores were calculated for each group. In addition, immunohistochemical (IHC) staining was performed to evaluate the expression of IL-1ß and TNF-α. Real-time fluorescence quantitative PCR was used to quantify the gene copy numbers of Escherichia, Bifidobacterium, and Lactobacillus in the cecum. The levels of amylase and plasma endotoxin in the SAP group were significantly higher than those in the SS and SS + Zn groups. Intestinal mucosal permeability and intestinal bacterial translocation in the liver, pancreas, and mesenteric lymph nodes were increased in the SAP group. However, the levels of amylase and plasma endotoxin were decreased as a result of zinc supplementation in the SAP group. The expression of IL-1ß and TNF-α was also reduced to a greater degree in the SAP + Zn group than in the SAP group. Moreover, alleviated intestinal mucosal permeability and intestinal bacterial translocation in the liver, pancreas, and mesenteric lymph nodes were found in the SAP + Zn group. The results of real-time quantitative PCR showed that the gene copy number of Escherichia increased with time, and the gene copy numbers of Lactobacillus and Bifidobacterium decreased over time. Zn supplementation prevented the release of TNF-α and IL-1ß, alleviated intestinal permeability and endotoxemia, reduced bacterial translocation, and inhibited changes in pathogenic intestinal flora in rats with SAP.

Oral Versus Gastrointestinal Mucosal Immune Niches in Homeostasis and Allostasis.

Different body systems (epidermis, respiratory tract, cornea, oral cavity, and gastrointestinal tract) are in continuous direct contact with innocuous and/or potentially harmful external agents, exhibiting dynamic and highly selective interaction throughout the epithelia, which function as both a physical and chemical protective barrier. Resident immune cells in the epithelia are constantly challenged and must distinguish among antigens that must be either tolerated or those to which a response must be mounted for. When such a decision begins to take place in lymphoid foci and/or mucosa-associated lymphoid tissues, the epithelia network of immune surveillance actively dominates both oral and gastrointestinal compartments, which are thought to operate in the same immune continuum. However, anatomical variations clearly differentiate immune processes in both the mouth and gastrointestinal tract that demonstrate a wide array of independent immune responses. From single vs. multiple epithelia cell layers, widespread cell-to-cell junction types, microbial-associated recognition receptors, dendritic cell function as well as related signaling, the objective of this review is to specifically contrast the current knowledge of oral versus gut immune niches in the context of epithelia/lymphoid foci/MALT local immunity and systemic output. Related differences in 1) anatomy 2) cell-to-cell communication 3) antigen capture/processing/presentation 4) signaling in regulatory vs. proinflammatory responses and 5) systemic output consequences and its relations to disease pathogenesis are discussed.

The Immunomodulatory Effect of the Gut Microbiota in Kidney Disease.

The human gut microbiota is a complex cluster composed of 100 trillion microorganisms, which holds a symbiotic relationship with the host under normal circumstances. Intestinal flora can facilitate the treatment of human metabolic dysfunctions and interact with the intestinal tract, which could influence intestinal tolerance, immunity, and sensitivity to inflammation. In recent years, significant interests have evolved on the association of intestinal microbiota and kidney diseases within the academic circle. Abnormal changes in intestinal microbiota, known as dysbiosis, can affect the integrity of the intestinal barrier, resulting in the bacterial translocation, production, and accumulation of dysbiotic gut-derived metabolites, such as urea, indoxyl sulfate (IS), and p-cresyl sulfate (PCS). These processes lead to the abnormal activation of immune cells; overproduction of antibodies, immune complexes, and inflammatory factors; and inflammatory cell infiltration that can directly or indirectly cause damage to the renal parenchyma. The aim of this review is to summarize the role of intestinal flora in the development and progression of several renal diseases, such as lupus nephritis, chronic kidney disease, diabetic nephropathy, and renal ischemia-reperfusion injury. Further research on these mechanisms should provide insights into the therapeutic potential of regulating intestinal flora and intervening related molecular targets for the abovementioned nephropathy.

The Architecture of Circulating Immune Cells Is Dysregulated in People Living With HIV on Long Term Antiretroviral Treatment and Relates With Markers of the HIV-1 Reservoir, Cytomegalovirus, and Microbial Translocation.

Long-term changes in the immune system of successfully treated people living with HIV (PLHIV) remain incompletely understood. In this study, we assessed 108 white blood cell (WBC) populations in a cohort of 211 PLHIV on stable antiretroviral therapy and in 56 HIV-uninfected controls using flow cytometry. We show that marked differences exist in T cell maturation and differentiation between PLHIV and HIV-uninfected controls: PLHIV had reduced percentages of CD4+ T cells and naïve T cells and increased percentages of CD8+ T cells, effector T cells, and T helper 17 (Th17) cells, together with increased Th17/regulatory T cell (Treg) ratios. PLHIV also exhibited altered B cell maturation with reduced percentages of memory B cells and increased numbers of plasmablasts. Determinants of the T and B cell composition in PLHIV included host factors (age, sex, and smoking), markers of the HIV reservoir, and CMV serostatus. Moreover, higher circulating Th17 percentages were associated with higher plasma concentrations of interleukin (IL) 6, soluble CD14, the gut homing chemokine CCL20, and intestinal fatty acid binding protein (IFABP). The changes in circulating lymphocytes translated into functional changes with reduced interferon (IFN)- γ responses of peripheral blood mononuclear cells to stimulation with Candida albicans and Mycobacterium tuberculosis. In conclusion, this comprehensive analysis confirms the importance of persistent abnormalities in the number and function of circulating immune cells in PLHIV on stable treatment.

Intestinal permeability changes with bacterial translocation as key events modulating systemic host immune response to SARS-CoV-2: A working hypothesis.

The microbiota-gut-liver-lung axis plays a bidirectional role in the pathophysiology of a number of infectious diseases. During the course of severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) and 2 (SARS-CoV-2) infection, this pathway is unbalanced due to intestinal involvement and systemic inflammatory response. Moreover, there is convincing preliminary evidence linking microbiota-gut-liver axis perturbations, proinflammatory status, and endothelial damage in noncommunicable preventable diseases with coronavirus disease 2019 (Covid-19) severity. Intestinal damage due to SARS-CoV-2 infection, systemic inflammation-induced dysfunction, and IL-6-mediated diffuse vascular damage may increase intestinal permeability and precipitate bacterial translocation. The systemic release of damage- and pathogen-associated molecular patterns (e.g. lipopolysaccharides) and consequent immune-activation may in turn auto-fuel vicious cycles of systemic inflammation and tissue damage. Thus, intestinal bacterial translocation may play an additive/synergistic role in the cytokine release syndrome in Covid-19. This review provides evidence on gut-liver axis involvement in Covid-19 as well as insights into the hypothesis that intestinal endotheliitis and permeability changes with bacterial translocation are key pathophysiologic events modulating systemic inflammatory response. Moreover, it presents an overview of readily applicable measures for the modulation of the gut-liver axis and microbiota in clinical practice.

Transient neonatal antibiotic exposure increases susceptibility to late-onset sepsis driven by microbiota-dependent suppression of type 3 innate lymphoid cells.

Extended early antibiotic exposure in the neonatal intensive care unit is associated with an increased risk for the development of late-onset sepsis (LOS). However, few studies have examined the mechanisms involved. We sought to determine how the neonatal microbiome and intestinal immune response is altered by transient early empiric antibiotic exposure at birth. Neonatal mice were transiently exposed to broad-spectrum antibiotics from birth for either 3- (SE) or 7-days (LE) and were examined at 14-days-old. We found that mice exposed to either SE or LE showed persistent expansion of Proteobacteria (2 log difference, P < 0.01). Further, LE mice demonstrated baseline translocation of E. coli into the liver and spleen and were more susceptible K. pneumoniae-induced sepsis. LE mice had a significant and persistent decrease in type 3 innate lymphoid cells (ILC3) in the lamina propria. Reconstitution of the microbiome with mature microbiota by gavage in LE mice following antibiotic exposure resulted in an increase in ILC3 and partial rescue from LOS. We conclude that prolonged exposure to broad spectrum antibiotics in the neonatal period is associated with persistent alteration of the microbiome and innate immune response resulting in increased susceptibility to infection that may be partially rescued by microbiome reconstitution.

Contribution of the Intestinal Microbiome and Gut Barrier to Hepatic Disorders.

Intestinal barrier dysfunction and dysbiosis contribute to development of diseases in liver and other organs. Physical, immunologic, and microbiologic (bacterial, fungal, archaeal, viral, and protozoal) features of the intestine separate its nearly 100 trillion microbes from the rest of the human body. Failure of any aspect of this barrier can result in translocation of microbes into the blood and sustained inflammatory response that promote liver injury, fibrosis, cirrhosis, and oncogenic transformation. Alterations in intestinal microbial populations or their functions can also affect health. We review the mechanisms that regulate intestinal permeability and how changes in the intestinal microbiome contribute to development of acute and chronic liver diseases. We discuss individual components of the intestinal barrier and how these are disrupted during development of different liver diseases. Learning more about these processes will increase our understanding of the interactions among the liver, intestine, and its flora.

Novel Forms of Immunomodulation for Cancer Therapy.

In recent years immunotherapy has provided new hope for cancer patients. However, some patients eventually relapse. Immunological responses are thought to underlie the long-term effects of conventional or targeted therapies. Whether this influence emerges from direct effects on cancer cells through immunogenic cell death (ICD) or by modulating the immune environment requires further clarification. ICD-related molecular mechanisms are also shared by cell-intrinsic defense responses that combat foreign intrusions. Indeed, we could potentially mimic and harness these processes to improve cancer immunogenicity. In addition, the microbiome is materializing as a missing factor in the cancer-immune therapy axis. The emerging idea of manipulating the gut microbiota to improve responses to anticancer therapy is becoming increasingly popular, but further clinical authentication is needed.

Adipose tissue derived bacteria are associated with inflammation in obesity and type 2 diabetes.

OBJECTIVE: Bacterial translocation to various organs including human adipose tissue (AT) due to increased intestinal permeability remains poorly understood. We hypothesised that: (1) bacterial presence is highly tissue specific and (2) related in composition and quantity to immune inflammatory and metabolic burden. DESIGN: We quantified and sequenced the bacterial 16S rRNA gene in blood and AT samples (omental, mesenteric and subcutaneous) of 75 subjects with obesity with or without type 2 diabetes (T2D) and used catalysed reporter deposition (CARD) - fluorescence in situ hybridisation (FISH) to detect bacteria in AT. RESULTS: Under stringent experimental and bioinformatic control for contaminants, bacterial DNA was detected in blood and omental, subcutaneous and mesenteric AT samples in the range of 0.1 to 5 pg/µg DNA isolate. Moreover, CARD-FISH allowed the detection of living, AT-borne bacteria. Proteobacteria and Firmicutes were the predominant phyla, and bacterial quantity was associated with immune cell infiltration, inflammatory and metabolic parameters in a tissue-specific manner. Bacterial composition differed between subjects with and without T2D and was associated with related clinical measures, including systemic and tissues-specific inflammatory markers. Finally, treatment of adipocytes with bacterial DNA in vitro stimulated the expression of TNFA and IL6. CONCLUSIONS: Our study provides contaminant aware evidence for the presence of bacteria and bacterial DNA in several ATs in obesity and T2D and suggests an important role of bacteria in initiating and sustaining local AT subclinical inflammation and therefore impacting metabolic sequelae of obesity.

Friend or foe? Lactobacillus in the context of autoimmune disease.

Over the last decade, the interplay between the gut microbiota, the consortium of intestinal microbes that colonizes intestinal mucosal barriers, and its host immune system has been increasingly better understood. Disruption of the delicate balance between beneficial and pathogenic commensals, known as dysbiosis, contributes to a variety of chronic immunologic and metabolic diseases. Complicating this paradigm are bacterial strains that can operate paradoxically both as instigators and attenuators of inflammatory responses, depending on host background. Here, we review the role of several strains in the genus Lactobacillus within the context of autoimmune and other chronic disorders with a predominant focus on L. reuteri. While strains within this species have been shown to provide immune health benefits, they have also been demonstrated to act as a pathobiont in autoimmune-prone hosts. Beneficial functions in healthy hosts include competing with pathogenic microbes, promoting regulatory T cell development, and protecting the integrity of the gut barrier. On the other hand, certain strains can also break through a dysfunctional gut barrier, colonize internal tissues such as the spleen or liver and promote inflammatory responses in host tissues that lead to autoimmune disease. This review summarizes the manifold roles that these commensals play in the context of health and disease.

Targeting zonulin and intestinal epithelial barrier function to prevent onset of arthritis.

Gut microbial dysbiosis is associated with the development of autoimmune disease, but the mechanisms by which microbial dysbiosis affects the transition from asymptomatic autoimmunity to inflammatory disease are incompletely characterized. Here, we identify intestinal barrier integrity as an important checkpoint in translating autoimmunity to inflammation. Zonulin family peptide (zonulin), a potent regulator for intestinal tight junctions, is highly expressed in autoimmune mice and humans and can be used to predict transition from autoimmunity to inflammatory arthritis. Increased serum zonulin levels are accompanied by a leaky intestinal barrier, dysbiosis and inflammation. Restoration of the intestinal barrier in the pre-phase of arthritis using butyrate or a cannabinoid type 1 receptor agonist inhibits the development of arthritis. Moreover, treatment with the zonulin antagonist larazotide acetate, which specifically increases intestinal barrier integrity, effectively reduces arthritis onset. These data identify a preventive approach for the onset of autoimmune disease by specifically targeting impaired intestinal barrier function.

Factors of microinflammation in non-diabetic chronic kidney disease: a pilot study.

BACKGROUND: The relationships between digestive bacterial translocation, uremic toxins, oxidative stress and microinflammation in a population of chronic kidney disease (CKD) patients without metabolic nor inflammatory disease are unknown. METHODS: Bacterial translocation, uremic toxins, oxidative stress, and inflammation were assessed by measuring plasma levels of 16S ribosomal DNA (16S rDNA), p-cresyl sulfate (PCS), indoxyl sulfate (IS), indole acetic acid (IAA), F2-isoprostanes, hsCRP and receptor I of TNFα (RITNFα) in patients without metabolic nor inflammatory disease. 44 patients with CKD from stage IIIB to V and 14 controls with normal kidney function were included from the nephrology outpatients. 11 patients under hemodialysis (HD) were also included. Correlations between each factor and microinflammation markers were studied. RESULTS: 16S rDNA levels were not increased in CKD patients compared to controls but were decreased in HD compared to non-HD stage V patients (4.7 (3.9-5.3) vs 8.6 (5.9-9.7) copies/µl, p = 0.002). IS, PCS and IAA levels increased in HD compared to controls (106.3 (73.3-130.4) vs 3.17 (2.4-5.1) µmol/l, p < 0.0001 for IS; 174.2 (125-227.5) vs 23.7 (13.9-52.6) µmol/l, p = 0.006 for PCS; and 3.7 (2.6-4.6) vs 1.3 (1.0-1.9) µmol/l, p = 0.0002 for IAA). Urea increased in non-HD stage V patients compared to controls (27.6 (22.7-30.9) vs 5.4 (4.8-6.4) mmol/l, p < 0.0001) and was similar in HD and in non-HD stage V (19.3 (14.0-24.0) vs 27.6 (22.7-30.9) mmol/l, p = 0.7). RITNFα levels increased in HD patients compared to controls (12.6 (9.6-13.3) vs 1.1 (1.0-1.4) ng/ml, p < 0.0001); hsCRP levels increased in non-HD stage V patients compared to controls (2.9 (1.4-8.5) vs 0.8 (0.5-1.7) mg/l, p = 0.01) and remained stable in HD patients (2.9 (1.4-8.5) vs 5.1 (0.9-11.5) mg/l, p = 1). F2-isoprostanes did not differ in CKD patients compared to controls. Among uremic toxins, IS and urea were correlated to RITNFα (r = 0.8, p < 0.0001 for both). PCS, IS and urea were higher in patients with hsCRP≧5 mg/l (p = 0.01, 0.04 and 0.001 respectively). 16S rDNA, F2-isoprostanes were not correlated to microinflammation markers in our study. CONCLUSIONS: In CKD patients without any associated metabolic nor inflammatory disease, only PCS, IS, and urea were correlated with microinflammation. Bacterial translocation was decreased in patients under HD and was not correlated to microinflammation.

Maternal activation of the EGFR prevents translocation of gut-residing pathogenic Escherichia coli in a model of late-onset neonatal sepsis.

Late-onset sepsis (LOS) is a highly consequential complication of preterm birth and is defined by a positive blood culture obtained after 72 h of age. The causative bacteria can be found in patients' intestinal tracts days before dissemination, and cohort studies suggest reduced LOS risk in breastfed preterm infants through unknown mechanisms. Reduced concentrations of epidermal growth factor (EGF) of maternal origin within the intestinal tract of mice correlated to the translocation of a gut-resident human pathogen Escherichia coli, which spreads systemically and caused a rapid, fatal disease in pups. Translocation of Escherichia coli was associated with the formation of colonic goblet cell-associated antigen passages (GAPs), which translocate enteric bacteria across the intestinal epithelium. Thus, maternally derived EGF, and potentially other EGFR ligands, prevents dissemination of a gut-resident pathogen by inhibiting goblet cell-mediated bacterial translocation. Through manipulation of maternally derived EGF and alteration of the earliest gut defenses, we have developed an animal model of pathogen dissemination which recapitulates gut-origin neonatal LOS.

Glycyrrhizin Protects γ-Irradiated Mice from Gut Bacteria-Associated Infectious Complications by Improving miR-222-Associated Gas5 RNA Reduction in Macrophages of the Bacterial Translocation Site.

Gut bacteria-associated sepsis is a serious concern in patients with gastrointestinal acute radiation syndrome (GIARS). In our previous studies, gut bacteria-associated sepsis caused high mortality rates in mice exposed to 6-9 Gy of γ-rays. IL-12+CD38+ iNOS+ Mϕ (M1Mϕ) located in the bacterial translocation site (mesenteric lymph nodes [MLNs]) of unirradiated mice were characterized as host defense antibacterial effector cells. However, cells isolated from the MLNs of GIARS mice were mostly CCL1+IL-10+LIGHT+miR-27a+ Mϕ (M2bMϕ, inhibitor cells for the M1Mϕ polarization). Reduced long noncoding RNA Gas5 and increased miR-222 expression in MLN-Mϕ influenced by the irradiation were shown to be associated with M2bMϕ polarization. In this study, the mortality of mice exposed to 7 Gy of γ-rays (7 Gy GIARS mice) was completely controlled after the administration of glycyrrhizin (GL), a major active ingredient in licorice root (Glycyrrhiza glabra). Bacterial translocation and subsequent sepsis were minimal in 7 Gy GIARS mice treated with GL. Increased Gas5 RNA level and decreased miR-222 expression were shown in MLN-Mϕ isolated from 7 Gy GIARS mice treated with GL, and these macrophages did not display any properties of M2bMϕ. These results indicate that gut bacteria-associated sepsis in 7 Gy GIARS mice was controlled by the GL through the inhibition of M2bMϕ polarization at the bacteria translocation site. Expression of Ccl1, a gene required for M2bMϕ survival, is silenced in the MLNs of 7 Gy GIARS mice because of Gas5 RNA, which is increased in these cells after the suppression of miR-222 (a Gas5 RNA expression inhibitor) by the GL.

Emerging Insights on the Interaction Between Anticancer and Immunosuppressant Drugs and Intestinal Microbiota in Pediatric Patients.

Diseases affecting the immune system, such as inflammatory bowel disease (IBD), juvenile idiopathic arthritis (JIA), and acute lymphoblastic leukemia (ALL), are pathological conditions affecting the pediatric population and are often associated with alterations in the intestinal microbiota, such as a decrease in bacterial diversity. Growing evidence suggests that gut microbiota can interfere with chemotherapeutic and immunosuppressant drugs, used in the treatment of these diseases, reducing or facilitating drug efficacy. In particular, the effect of intestinal microflora through translocation, immunomodulation, metabolism, enzymatic degradation, and reduction of bacterial diversity seems to be one of the reasons of interindividual variability in the therapeutic response. Although the extent of the role of intestinal microflora in chemotherapy and immunosuppression remains still unresolved, current evidence on bacterial compositional shifts will be taken in consideration together with clinical response to drugs for a better and personalized therapy. This review is focused on the effect of the intestinal microbiota on the efficacy of pharmacological therapy of agents used to treat IBD, JIA, and ALL.

Mechanisms and consequences of gut commensal translocation in chronic diseases.

Humans and other mammalian hosts have evolved mechanisms to control the bacteria colonizing their mucosal barriers to prevent invasion. While the breach of barriers by bacteria typically leads to overt infection, increasing evidence supports a role for translocation of commensal bacteria across an impaired gut barrier to extraintestinal sites in the pathogenesis of autoimmune and other chronic, non-infectious diseases. Whether gut commensal translocation is a cause or consequence of the disease is incompletely defined. Here we discuss factors that lead to translocation of live bacteria across the gut barrier. We expand upon our recently published demonstration that translocation of the gut pathobiont Enterococcus gallinarum can induce autoimmunity in susceptible hosts and postulate on the role of Enterococcus species as instigators of chronic, non-infectious diseases.