The morbidity of NASH has increased, with limited effective treatment options. IL-17 plays a protective role in the gut mucosa in high-fat-diet (HFD)-related metabolic disorders, and HFD-related microbiota dysbiosis is responsible for a decreased number of T helper 17 (T _H 17) cells in the lamina propria.

Purpose: MicroRNA-146b (miR-146b) alleviates experimental colitis in mice by mediating macrophage polarization and the release of inflammatory factors. Our goals were to evaluate the antitumor efficacy of miR-146b in colorectal cancer (CRC) and to investigate the underlying mechanisms. Methods: We used murine models of CRC to evaluate whether miR-146b influenced the progression of tumors independent of tumor-associated macrophages (TAMs). RNA immunoprecipitation, N6-methyladenosine (m⁶A) RNA immunoprecipitation and in vitro pri-miRNA processing assays were conducted to examine whether m⁶A mediates the maturation of pri-miR-146b/miR-146b. In a series of in vitro and in vivo experiments, we further defined the molecular mechanisms of methyltransferase-like 3 (METTL3)/miR-146b-mediated antitumor immunity and its efficacy in combination with anti-PD-1 immunotherapy. Results: We found that miR-146b deletion supported tumor progression by increasing the number of alternatively activated (M2) TAMs. Mechanistically, the m⁶A-related “writer” protein METTL3 and “reader” protein HNRNPA2B1 controlled miR-146b maturation by regulating the m⁶A modification region of pri-miR-146b. Furthermore, miR-146b deletion promoted the polarization of M2-TAMs by enhancing phosphoinositide 3-kinase (PI3K)/AKT signaling, and this effect was mediated by the class IA PI3K catalytic subunit p110β, which reduced T cell infiltration, aggravated immunosuppression and ultimately promoted tumor progression. METTL3 knockdown or miR-146b deletion induced programmed death ligand 1 (PD-L1) production via the p110β/PI3K/AKT pathway in TAMs and consequently augmented the antitumor activity of anti-PD-1 immunotherapy. Conclusions: The maturation of pri-miR-146b is m⁶A-dependent, and miR-146b deletion-mediated TAM differentiation promotes the development of CRC by activating the PI3K/AKT pathway, which induces upregulation of PD-L1 expression, inhibits T cell infiltration into the TME and enhances the antitumor activity of anti-PD-1 immunotherapy. The findings reveal that targeting miR-146b can serve as an adjuvant to anti-PD-1 immunotherapy. Graphical

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide, and precision therapeutic will be a benefit for the NAFLD regression. In this study, we observed low microRNA 146 b (miR-146 b) expression in NAFLD mice model induced by methionine–choline-deficient diet (MCD) compared with control group. Furthermore, miR-146b^−/− mice induced MCD exhibited severe liver steatosis and hepatitis. A bio-distribution study showed that novel Lactosylated PDMAEMA nanoparticles effectively targeted hepatocytes Lac-PDMAEMA. We coupled miR-146b mimic with Lac-PDMAEMA and then were administrated to NAFLD mice model, which could obviously alleviate the hepatic steatosis. Lac-PDMAEMA effectively delivered miR-146b mimic to hepatocytes with a ∼8-fold upregulation of miR-146b mimic targeting MyD88 and IRAK1, and in turn suppressed the expression of PPARγ. Meanwhile, TNF-α and IL-6 mRNA levels were decreased after administration of Lac-PDMAEMA/miR-146b mimic. So, we made a conclusion that targeted delivering miR-146b mimic to the hepatocytes by, coupling Lac-PDMAEMA nanoparticles could effectively alleviate the hepatic steatosis in NAFLD mice, which maybe bring a new and effective way to intervene and therapy the NAFLD.

Background: Insulin has been reported to exhibit anti-inflammatory activities in the context of bowel inflammation. However, the role of the interaction between insulin and the microbiota in gut health is unclear. Our goal was to investigate the mechanism of action of insulin in bowel inflammation and the relationship between insulin and the gut microbiota. Methods: We used acute and chronic murine models of inflammatory bowel disease (IBD) to evaluate whether insulin influences the progression of colitis. Colonic tissues, the host metabolome and the gut microbiome were analyzed to investigate the relationship among insulin treatment, the microbiome, and disease. Experiments involving antibiotic (Abx) treatment and fecal microbiota transplantation (FMT) confirmed the association among the gut microbiota, insulin and IBD. In a series of experiments, we further defined the mechanisms underlying the anti-inflammatory effects of insulin. Results: We found that low-dose insulin treatment alleviated intestinal inflammation but did not cause death. These effects were dependent on the gut microbiota, as confirmed by experiments involving Abx treatment and FMT. Using untargeted metabolomic profiling and 16S rRNA sequencing, we discovered that the level of the secondary bile acid lithocholic acid (LCA) was notably increased and the LCA levels were significantly associated with the abundance of Blautia, Enterorhadus and Rumi-NK4A214_group. Furthermore, LCA exerted anti-inflammatory effects by activating a G-protein-coupled bile acid receptor (TGR5), which inhibited the polarization of classically activated (M1) macrophages. Conclusion: Together, these data suggest that insulin alters the gut microbiota and affects LCA production, ultimately delaying the progression of IBD. Graphical