NLRP6 deficiency expands a novel CD103 + B cell population that confers immune tolerance in NOD mice

Introduction: Gut microbiota have been linked to modulating susceptibility to Type 1 diabetes; however, there are many ways in which the microbiota interact with host cells, including through microbial ligand binding to intracellular inflammasomes (large multi-subunit proteins) to initiate immune responses. NLRP6, a microbe-recognizing inflammasome protein, is highly expressed by intestinal epithelial cells and can alter susceptibility to cancer, obesity and Crohn’s disease; however, the role of NLRP6 in modulating susceptibility to autoimmune diabetes, was previously unknown. Methods: We generated NLRP6-deficient Non-obese diabetic (NOD) mice to study the effect of NLRP6-deficiency on the immune cells and susceptibility to Type 1 diabetes development. Results: NLRP6-deficient mice exhibited an expansion of CD103+ B cells and were protected from type 1 diabetes. Moreover, NLRP6-deficient CD103+ B cells express regulatory markers, secreted higher concentrations of IL-10 and TGFb1 cytokines and suppressed diabetogenic T cell proliferation, compared to NLRP6-sufficient CD103+ B cells. Microarray analysis of NLRP6-sufficient and -deficient CD103+ B cells identified 79 significantly different genes including genes regulated by lipopolysaccharide (LPS), tretinoin, IL-10 and TGFb, which was confirmed in vitro following LPS stimulation. Furthermore, microbiota from NLRP6-deficient mice induced CD103+ B cells in colonized NLRP6-sufficient germ-free mice; however, the long-term maintenance of the CD103+ B cells required the absence of NLRP6 in the hosts, or continued exposure to microbiota from NLRP6-deficient mice. Discussion: Together, our data indicate that NLRP6 deficiency promotes expansion and maintenance of a novel TGF -dependent CD103+ Breg population. Thus, targeting NLRP6 therapeutically may prove clinically useful

TLR9-deficiency in B cells promotes immune tolerance via IL-10 in a type 1 diabetes mouse model

Toll-like receptor 9 (TLR9) is highly expressed in B cells and B cells are important in the pathogenesis of type 1 diabetes (T1D) development. However, the intrinsic effect of TLR9 in B cells on beta cell autoimmunity is not known. To fill this knowledge gap, we generated non-obese diabetic (NOD) mice with a B cell-specific deficiency of TLR9 (TLR9fl/fl/CD19-Cre+ NOD). The B cell-specific deletion of TLR9 resulted in near complete protection from T1D development. Diabetes protection was accompanied by an increased proportion of IL-10-producing B cells. We also found that TLR9-deficient B cells were hyporesponsive to both innate and adaptive immune-stimuli. This suggested that TLR9 in B cells modulates T1D susceptibility in NOD mice by changing the frequency and function of IL-10-producing B cells. Molecular analysis revealed a network of TLR9 with MMPs, TIMP1 and CD40, all of which are inter-connected with IL-10. Our study has highlighted an important connection of an innate immune molecule in B cells to the immuno-pathogenesis of T1D. Thus, targeting the TLR9 pathway, specifically in B cells, may provide a novel therapeutic strategy for T1D treatment

Tlr9 deficiency in B cells leads to obesity by promoting inflammation and gut dysbiosis

Toll-like receptor 9 (TLR9) recognizes bacterial, viral and self DNA and play an important role in immunity and inflammation. However, the role of TLR9 in obesity is less well-studied. Here, we generate B-cell-specific Tlr9-deficient (Tlr9fl/fl/Cd19Cre+/-, KO) B6 mice and model obesity using a high-fat diet. Compared with control mice, B-cell-specific-Tlr9-deficient mice exhibited increased fat tissue inflammation, weight gain, and impaired glucose and insulin tolerance. Furthermore, the frequencies of IL-10-producing-B cells and marginal zone B cells were reduced, and those of follicular and germinal center B cells were increased. This was associated with increased frequencies of IFNγ-producing-T cells and increased follicular helper cells. In addition, gut microbiota from the KO mice induced a pro-inflammatory state leading to immunological and metabolic dysregulation when transferred to germ-free mice. Using 16 S rRNA gene sequencing, we identify altered gut microbial communities including reduced Lachnospiraceae, which may play a role in altered metabolism in KO mice. We identify an important network involving Tlr9, Irf4 and Il-10 interconnecting metabolic homeostasis, with the function of B and T cells, and gut microbiota in obesity

IL-10 deficiency accelerates type 1 diabetes development via modulation of innate and adaptive immune cells and gut microbiota in BDC2.5 NOD mice

Type 1 diabetes is an autoimmune disease caused by T cell-mediated destruction of insulin-producing β cells. BDC2.5 T cells in BDC2.5 CD4+ T cell receptor transgenic Non-Obese Diabetic (NOD) mice (BDC2.5+ NOD mice) can abruptly invade the pancreatic islets resulting in severe insulitis that progresses rapidly but rarely leads to spontaneous diabetes. This prevention of diabetes is mediated by T regulatory (Treg) cells in these mice. In this study, we investigated the role of interleukin 10 (IL-10) in the inhibition of diabetes in BDC2.5+ NOD mice by generating Il-10-deficient BDC2.5+ NOD mice (BDC2.5+Il-10-/- NOD mice). Our results showed that BDC2.5+Il-10-/- NOD mice displayed robust and accelerated diabetes development. Il-10 deficiency in BDC2.5+ NOD mice promoted the generation of neutrophils in the bone marrow and increased the proportions of neutrophils in the periphery (blood, spleen, and islets), accompanied by altered intestinal immunity and gut microbiota composition. In vitro studies showed that the gut microbiota from BDC2.5+Il-10-/- NOD mice can expand neutrophil populations. Moreover, in vivo studies demonstrated that the depletion of endogenous gut microbiota by antibiotic treatment decreased the proportion of neutrophils. Although Il-10 deficiency in BDC2.5+ NOD mice had no obvious effects on the proportion and function of Treg cells, it affected the immune response and activation of CD4+ T cells. Moreover, the pathogenicity of CD4+ T cells was much increased, and this significantly accelerated the development of diabetes when these CD4+ T cells were transferred into immune-deficient NOD mice. Our study provides novel insights into the role of IL-10 in the modulation of neutrophils and CD4+ T cells in BDC2.5+ NOD mice, and suggests important crosstalk between gut microbiota and neutrophils in type 1 diabetes development

Changing Attitudes Towards COVID-19 Countermeasures among Chinese Citizens

Contains dataset and AMOS files for the study for replication. "COVID_3wave.sav" Contains all data used in this study. All variable names are in Chinese. Variables in Amos files have been labeled by their English names

Quantifying the seasonal contribution of coupling urban land use types on Urban Heat Island using Land Contribution Index: A case study in Wuhan, China

Urban Heat Island (UHI) is an urban climate phenomenon which is expected to respond to the change of urban environment and land use types in the future. UHI is closely related to urbanization and urban land use changes, since the expansion of impervious surface greatly affects the thermodynamic properties of the underlying surface. New ways to measure and assess the inner quantitative relationship between land use types and UHI are thus critical to answer the questions in this field. This paper presents a new method for better quantifying the contribution of respective land use type on UHI with the proposed Land Contribution Index (LCI). Seasonal thermal contribution of each land use type to UHI can be calculated based on the difference in average temperatures between a certain land use type and the entire study area. The experiment was conducted in Wuhan, China during 2005–2015 when the city was in rapid urbanization. Results indicate that the UHI effect has become more prominent in areas of rapid urbanization in the study area, and strong UHI (including high level and extremely high level) accounted for 8.56% of the whole region in 2015 compared with 2005 (3.35%). In addition, through analyzing temporal and spatial patterns of the distribution of UHI, increasing UHI areas were mainly distributed in the central and western parts of the city during 2005–2009, and then migrated to the surroundings from 2011. Furthermore, based on the calculation of LCI, construction land had the highest contribution to the UHI effect in the summer of 2015, while water body had conversely the lowest contribution to the UHI effect in the spring of 2005. Urban green space including forest land and agricultural land had intensively negative contributions to the UHI effect, and their alleviating functions on the thermal environment were less remarkable in winter