Protein arginine methyltransferase 5-mediated arginine methylation stabilizes Kruppel-like factor 4 to accelerate neointimal formation.

AIMS: Accumulating evidence supports the indispensable role of protein arginine methyltransferase 5 (PRMT5) in the pathological progression of several human cancers. As an important enzyme-regulating protein methylation, how PRMT5 participates in vascular remodelling remains unknown. The aim of this study was to investigate the role and underlying mechanism of PRMT5 in neointimal formation and to evaluate its potential as an effective therapeutic target for the condition. METHODS AND RESULTS: Aberrant PRMT5 overexpression was positively correlated with clinical carotid arterial stenosis. Vascular smooth muscle cell (SMC)-specific PRMT5 knockout inhibited intimal hyperplasia with an enhanced expression of contractile markers in mice. Conversely, PRMT5 overexpression inhibited SMC contractile markers and promoted intimal hyperplasia. Furthermore, we showed that PRMT5 promoted SMC phenotypic switching by stabilizing Kruppel-like factor 4 (KLF4). Mechanistically, PRMT5-mediated KLF4 methylation inhibited ubiquitin-dependent proteolysis of KLF4, leading to a disruption of myocardin (MYOCD)-serum response factor (SRF) interaction and MYOCD-SRF-mediated the transcription of SMC contractile markers. CONCLUSION: Our data demonstrated that PRMT5 critically mediated vascular remodelling by promoting KLF4-mediated SMC phenotypic conversion and consequently the progression of intimal hyperplasia. Therefore, PRMT5 may represent a potential therapeutic target for intimal hyperplasia-associated vascular diseases.

Biochanin A ameliorates caerulein-induced acute pancreatitis and associated intestinal injury in mice by inhibiting TLR4 signaling.

Acute pancreatitis (AP) is an acute inflammatory abdominal disease frequently associated with intestinal barrier dysfunction. Biochanin A (BCA), a dietary isoflavone, has gained increasing interest with its pronounced biological activities. However, its potential beneficial effects on AP have not been demonstrated. Herein, we explored the protective effect of BCA on caerulein-induced AP in BALB/c mice and underlying mechanisms. BCA alleviated AP as evidenced by reduced serum amylase and lipase levels, pancreatic edema, pancreatic myeloperoxidase activity, and improved pancreatic morphology. Amelioration of pancreatic damage by BCA was associated with reduced levels of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and monocyte chemotactic protein-1 in both pancreas and colon. Moreover, BCA attenuated AP-associated barrier damage by upregulating the expression of tight junction proteins zonulin occluding (ZO)-1, ZO-2, occludin, and claudin-1. Concomitantly, the translocation of pathogenic bacteria Escherichia coli (E. coli) to pancreas was reduced by BCA. More importantly, reduction of E. coli dissemination by BCA inhibited the TLR4-MAPK/NF-κB signaling and NLRP3 inflammasome activation, thereby protecting against AP and related intestinal injury. Consistently, TLR4 inhibition by TAK-242 pre-treatment counteracted the anti-inflammatory effects of BCA in acinar cells. Taken together, our study extends beneficial effects of BCA to AP prevention, and dietary BCA supplement may be a potential strategy to safeguard AP.

Opportunities and challenges of polyphenols and polysaccharides for type 1 diabetes intervention.

Type 1 diabetes (T1D) is an autoimmune disorder characterized by the destruction of insulin-producing pancreatic ß cell. It contributes to high mortality, frequent diabetic complications, poor quality of life in patients and also puts a significant economic burden on health care systems. Therefore, the development of new therapeutic strategies is urgently needed. Recently, certain dietary compounds with potential applications in food industry, particularly polyphenols and polysaccharides, have gained increasing attention with their prominent anti-diabetic effects on T1D by modulating ß cell function, the gut microbiota and/or the immune system. In this review, we critically discuss the recent findings of several dietary polyphenols and polysaccharides with the potential to protect against T1D and the underlying anti-diabetic mechanisms. More importantly, we highlight the current trends, major issues, and future directions of industrial production of polyphenols- and polysaccharides-based functional foods for preventing or delaying T1D.

Enteral virus depletion modulates experimental acute pancreatitis via toll-like receptor 9 signaling.

Enteric viruses that inhabit the intestine have profound effects on innate and adaptive immunity of the gut and thus distant organs. Acute pancreatitis (AP) is a common abdominal inflammatory disease, in which gut bacteria play an indispensable part, particularly in the severe form with local and systemic complications. So far, little is known about the role of enteric viruses in the pathophysiology of AP. In this study, we evaluated the effect of enteric virus depletion by oral anti-viral cocktail (AVC) on caerulein (Cae)-hyperstimulation induced experimental AP and underlying mechanisms. We found that AVC treatment alleviated experimental AP, accompanied by suppressed innate immune cell infiltration and TLR9 expression and signaling in pancreas and intestine. Furthermore, AVC administration reduced AP-induced interleukin-6 (IL-6) production, IL-6-activated signal transducers and activators of transcription 3 (STAT3) signaling. Concordantly, expression of AP-induced STAT3-responsive chemokines, especially monocyte chemotactic protein-1 (MCP-1) and chemokine (C-X-C motif) ligand 1 (CXCL1) was reduced, thereby contributing to modulated pancreatic immune milieu. Treatment of mice with a toll-like receptor 9 (TLR9) agonist abolished the protective effect of AVC by activation of IL6/STAT3 signaling and downstream chemokine production. Conversely, treatment of mice with TLR9 antagonists, mimicking AVC, exerted protective effects against AP. Collectively, these results suggest that depletion of enteric viruses protects mice from experimental AP through inhibiting TLR9 signaling. Our study therefore implies a previously unrecognized role of enteric viruses in AP.

Effect of exogenous γ-aminobutyric acid treatment on the enzymatic browning of fresh-cut potato during storage.

The aim of this study was to evaluate the effect of γ-aminobutyric acid (GABA) treatment on the enzymatic browning of fresh-cut potatoes. The browning index and activities of browning and defense-related enzymes were analyzed after 0, 1, 2, 3, 4, 5, and 6 days of storage at 4 °C. The results showed that the treatment with 20 g/L GABA for 10 min significantly retarded the browning of fresh-cut potatoes. GABA inhibited the browning of fresh-cut potatoes by enhancing the activities of catalase and superoxide dismutase, and decreasing the activities of polyphenol oxidase and reactive oxygen species. The results suggest that GABA plays an important role in reducing the browning of fresh-cut potatoes. Hence, GABA treatment is a promising approach for reducing the browning and maintaining the quality of fresh-cut potatoes.

A Novel Derivative of the Natural Product Danshensu Suppresses Inflammatory Responses to Alleviate Caerulein-Induced Acute Pancreatitis.

Acute pancreatitis (AP), a common abdominal inflammatory disorder, is characterized by premature intracellular activation of digestive proteases within pancreatic acini and a consecutive systemic inflammatory response. Although the mechanism remains to be fully understood, inflammation is the main cause of pancreatic damage in AP. A novel compound [4-(2-acetoxy-3-((R)-3-(benzylthio)-1-methoxy-1-oxopropan-2-ylamino)-3-oxopropyl)-1,2-phenylene diacetate (DSC)], derived from danshensu, exhibits anti-inflammatory and anti-apoptotic properties in vitro. However, its potential beneficial effect in AP has not been demonstrated. This study aimed to investigate the effects and underlying mechanisms of DSC in experimental AP in mice. We found that DSC suppressed inflammatory responses in AP by inhibiting the activation of nuclear factor-κB (NF-κB), signal transducer and activator of transcription 3 (STAT3) and nucleotide-binding domain leucine-rich repeat containing family, pyrin domain-containing 3 (NLRP3) inflammasome. Furthermore, treatment with DSC modulated the infiltration of neutrophils and the phenotypes of macrophages in mice induced with AP. Interestingly, we found that the expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) and its regulated antioxidant enzyme heme oxygenase-1 (HO-1), which modulate inflammatory activities, was significantly increased in DSC-treated groups. Together, our findings demonstrate that DSC alleviates pancreatic inflammation and damage in AP by inhibiting the activation of NF-κB, STAT3, and NLRP3 inflammasome and modulating immune cell responses.