TLR9 Regulates the NF-κB-NLRP3-IL-1ß Pathway Negatively in Salmonella-Induced NKG2D-Mediated Intestinal Inflammation.

TLRs are key sensors for conserved bacterial molecules and play a critical role in host defense against invading pathogens. Although the roles of TLRs in defense against pathogen infection and in maintaining gut immune homeostasis have been studied, the precise functions of different TLRs in response to pathogen infection in the gut remain elusive. The present study investigated the role of TLR signaling in defense against the Gram-negative bacterial pathogen Salmonella typhimurium The results indicated that TLR9-deficient mice were more susceptible to S. typhimurium infection compared with wild-type and TLR2- or TLR4-deficient mice, as indicated by more severe intestinal damage and the highest bacterial load. TLR9 deficiency in intestinal epithelial cells (IECs) augmented the activation of NF-κB and NLRP3 inflammasomes significantly, resulting in increased secretion of IL-1ß. IL-1ß increased the expression of NKG2D on intestinal intraepithelial lymphocytes and NKG2D ligands on IECs, resulting in higher susceptibility of IECs to cytotoxicity of intestinal intraepithelial lymphocytes and damage to the epithelial barrier. We proposed that TLR9 regulates the NF-κB-NLRP3-IL-1ß pathway negatively in Salmonella-induced NKG2D-mediated intestinal inflammation and plays a critical role in defense against S. typhimurium infection and in the protection of intestinal integrity.

Intestinal Lamina Propria CD4+ T Cells Promote Bactericidal Activity of Macrophages via Galectin-9 and Tim-3 Interaction during Salmonella enterica Serovar Typhimurium Infection.

The intestinal immune system is crucial for protection from pathogenic infection and maintenance of mucosal homeostasis. We studied the intestinal immune microenvironment in a Salmonella enterica serovar Typhimurium intestinal infection mouse model. Intestinal lamina propria macrophages are the main effector cells in innate resistance to intracellular microbial pathogens. We found that S Typhimurium infection augmented Tim-3 expression on intestinal lamina propria CD4+ T cells and enhanced galectin-9 expression on F4/80+ CD11b+ macrophages. Moreover, CD4+ T cells promoted the activation and bactericidal activity of intestinal F4/80+ CD11b+ macrophages via the Tim-3/galectin-9 interaction during S Typhimurium infection. Blocking the Tim-3/galectin-9 interaction with α-lactose significantly attenuated the bactericidal activity of intracellular S Typhimurium by macrophages. Furthermore, the Tim-3/galectin-9 interaction promoted the formation and activation of inflammasomes, which led to caspase-1 cleavage and interleukin 1ß (IL-1ß) secretion. The secretion of active IL-1ß further improved bactericidal activity of macrophages and galectin-9 expression on macrophages. These results demonstrated the critical role of the cross talk between CD4+ T cells and macrophages, particularly the Tim-3/galectin-9 interaction, in antimicrobial immunity and the control of intestinal pathogenic infections.

Berberine and Its Main Metabolite Berberrubine Inhibit Platelet Activation Through Suppressing the Class I PI3Kß/Rasa3/Rap1 Pathway.

Background: Berberine (BBR), a natural product, was reported to inhibit platelet aggregation; however, the molecular mechanisms remain unclear. This study aims to investigate the effects and mechanisms of BBR in inhibiting platelet activation and thrombus formation. Methods: Flow cytometry, immunofluorescence, and Western blot were used to determine the inhibitory effects and mechanisms of BBR and its main metabolite berberrubine (M2) on platelet activation in vitro and ex vivo. Purified integrin αIIbß3, class I PI3K kit, and molecular docking were used to identify the possible targets of BBR and M2. A carrageenan-induced mouse thrombosis model was used to evaluate the effects of BBR on thrombus formation in vivo. Results: In vitro, BBR and M2 significantly inhibited ADP-induced integrin αIIbß3 activation, reduced the level of P-selectin on the platelet membrane, and suppressed the binding of fibrinogen to the platelets. In this process, BBR and M2 greatly suppressed the PI3K/Akt pathway and inhibited Rasa3 membrane translocation and Rap1 activation. Furthermore, BBR and M2 selectively inhibited class I PI3Kß, perhaps through binding to its active site. The activities of BBR were stronger than those of M2. After oral administration, BBR significantly inhibited the PI3K/Akt pathway and Rap1 activation and suppressed ADP-induced platelet activation and carrageenan-induced thrombosis in mice without prolonging bleeding time. Conclusions: We reveal for the first time the possible targets and mechanisms of BBR and M2 in inhibiting platelet activation. Our research may support the future clinical application of BBR as an antiplatelet drug in the prevention or treatment of thrombotic diseases.

Berberine inhibits adipocyte differentiation, proliferation and adiposity through down-regulating galectin-3.

This study is designed to investigate the effects of berberine (BBR) on galectin-3 (Gal-3) and the relationships to its suppressive activities on adipocyte differentiation, proliferation and adiposity. Our results showed that BBR greatly suppressed the differentiation and proliferation of mouse primary preadipocytes isolated from epididymal white adipose tissue (eWAT), during which the expression level of Gal-3 was down-regulated significantly. Overexpression of Gal-3 totally abolished the suppressive activities of BBR on Gal-3 expression, preadipocyte differentiation and proliferation. BBR reduced Gal-3 promoter activity, destabilized its mRNA and inhibited firefly luciferase activity of a recombinant plasmid containing the Gal-3 3' untranslated region (UTR). Furthermore, BBR up-regulated microRNA (miRNA) let-7d expression and the suppressive activity on Gal-3 3'UTR was abolished by point mutation on the let-7d binding site. In mice fed a high-fat diet (HFD), BBR up-regulated let-7d and down-regulated Gal-3 expression in eWAT; it also suppressed adipocyte differentiation and proliferation and reduced adiposity greatly. In summary, our study proves that BBR inhibits the differentiation and proliferation of adipocytes through down-regulating Gal-3, which is closely associated with its anti-obesity effect. Our results may support the future clinical application of BBR for the treatment of obesity or related diseases.

[Expression of a human myofibrillogenesis regulator 1 gene in E. coli and its immunogenicity].

OBJECTIVE: To study the expression of human myofibrillogenesis regulator 1 (MR-1) gene in E. coli and obtain the MR-1 protein and its antibody for further investigation of its biological function. METHODS: Expression vectors pGEX-5X-1, pET30a (+), and pET24a (+), as well as host strain E. coli BL21 (DE3) and BL21-CodonPlus (DE3) -RIL were used for expression of MR-1. MR-1 N-terminal with GST or T7-tag or C-terminal with His-tag, separately, or N terminal with T7-tag and C terminal with His-tag, simultaneously, were fused in plasmids pGEX-5X-1, pET30a (+) , and pET24a (+). The expressed MR-1-T protein, separated and purified by preparative SDS-PAGE, was applied to immunize the rabbits. The titer of the antibody was assayed by ELISA and its immunogenicity was tested by Western blot with pcDNA3/MR-1 transfected human breast cancer cell MCF7. RESULTS: The MR-1 protein was successfully expressed as inclusion body by fusing its N-terminal with T7-tag in E. coli BL21-CodonPlus (DE3) -RIL. MR-1 protein was purified by electro-elution from SDS-PAGE gel. Using this purified protein, polyclonal antibody in rabbit against MR-1 was essentially generated. ELISA and Western blot showed the titer of this antibody was about 1:10(5) with high immunogenicity. CONCLUSIONS: The N-terminal fusion tag is the most important mechanism for MR-1 expression. The polyclonal antibody of the generated MR-1 protein in E. coli may be applied for its further biological function studies.

Berberine analogues as a novel class of the low-density-lipoprotein receptor up-regulators: synthesis, structure-activity relationships, and cholesterol-lowering efficacy.

Twenty-nine derivatives of berberine (1) or pseudoberberine (2) were designed, semisynthesized, and evaluated for their up-regulatory activity on the low-density-lipoprotein receptor (LDLR) expression. SAR analysis revealed that (i) the methylenedioxy group at the 2- and 3-position is an essential element to keep the activity, (ii) the 7-position quaternary ammonium and planar structure of the compound are activity-required, and (iii) addition of electron-donating groups at the 7- or 13-position reduced the activity. Of the compound 1 analogues, compound 2 exhibited an increased activity on LDLR expression compared to 1. In the hyperlipidemic rats, compound 2 (100 (mg/kg)/day) reduced blood CHO and LDL-c by 42.6% and 49.4%, respectively, more efficient than 1 did (p < 0.01 for both). The results were confirmed in the hyperlipidemic mice. LD(50) of 2 in mice was over 5000 mg/kg (oral). We consider compound 2 a promising cholesterol-lowering drug candidate.

Combination of simvastatin with berberine improves the lipid-lowering efficacy.

We have identified berberine (BBR) as a novel cholesterol-lowering drug acting through stabilization of the low-density lipoprotein receptor (LDLR) messenger RNA. Because the mechanism differs from that of statins, it is of great interest to examine the lipid-lowering activity of BBR in combination with statins. Our results showed that combination of BBR with simvastatin (SIMVA) increased the LDLR gene expression to a level significantly higher than that in monotherapies. In the treatment of food-induced hyperlipidemic rats, combination of BBR (90 mg/[kg d], oral) with SIMVA (6 mg/[kg d], oral) reduced serum LDL cholesterol by 46.2%, which was more effective than that of the SIMVA (28.3%) or BBR (26.8%) monotherapy (P < .01 for both) and similar to that of SIMVA at 12 mg/(kg d) (43.4%). More effective reduction of serum triglyceride was also achieved with the combination as compared with either monotherapy. Combination of BBR with SIMVA up-regulated the LDLR messenger RNA in rat livers to a level about 1.6-fold higher than the monotherapies did. Significant reduction of liver fat storage and improved liver histology were found after the combination therapy. The therapeutic efficacy of the combination was then evaluated in 63 hypercholesterolemic patients. As compared with monotherapies, the combination showed an improved lipid-lowering effect with 31.8% reduction of serum LDL cholesterol (P < .05 vs BBR alone, P < .01 vs SIMVA alone). Similar efficacies were observed in the reduction of total cholesterol as well as triglyceride in the patients. Our results display the rationale, effectiveness, and safety of the combination therapy for hyperlipidemia using BBR and SIMVA. It could be a new regimen for hypercholesterolemia.