Gut microbiota-derived nicotinamide mononucleotide alleviates acute pancreatitis by activating pancreatic SIRT3 signalling.

BACKGROUND AND PURPOSE: Gut microbiota dysbiosis induced by acute pancreatitis (AP) exacerbates pancreatic injury and systemic inflammatory responses. The alleviation of gut microbiota dysbiosis through faecal microbiota transplantation (FMT) is considered a potential strategy to reduce tissue damage and inflammation in many clinical disorders. Here, we aim to investigate the effect of gut microbiota and microbiota-derived metabolites on AP and further clarify the mechanisms associated with pancreatic damage and inflammation. EXPERIMENTAL APPROACH: AP rat and mouse models were established by administration of caerulein or sodium taurocholate in vivo. Pancreatic acinar cells were exposed to caerulein and lipopolysaccharide in vitro to simulate AP. KEY RESULTS: Normobiotic FMT alleviated AP-induced gut microbiota dysbiosis and ameliorated the severity of AP, including mitochondrial dysfunction, oxidative damage and inflammation. Normobiotic FMT induced higher levels of NAD+ (nicotinamide adenine dinucleotide)-associated metabolites, particularly nicotinamide mononucleotide (NMN). NMN administration mitigated AP-mediated mitochondrial dysfunction, oxidative damage and inflammation by increasing pancreatic NAD+ levels. Similarly, overexpression of the NAD+ -dependent mitochondrial deacetylase sirtuin 3 (SIRT3) alleviated the severity of AP. Furthermore, SIRT3 deacetylated peroxiredoxin 5 (PRDX5) and enhanced PRDX5 protein expression, thereby promoting its antioxidant and anti-inflammatory activities in AP. Importantly, normobiotic FMT-mediated NMN metabolism induced SIRT3-PRDX5 pathway activation during AP. CONCLUSION AND IMPLICATIONS: Gut microbiota-derived NMN alleviates the severity of AP by activating the SIRT3-PRDX5 pathway. Normobiotic FMT could be served as a potential strategy for AP treatment.

Gut microbiota patterns associated with somatostatin in patients undergoing pancreaticoduodenectomy: a prospective study.

Postoperative pancreatic fistula (POPF) is a common and dreaded complication after pancreaticoduodenectomy (PD). The gut microbiota has been considered as an crucial mediator of postoperative complications, however, the precise roles of gut microbiota in POPF are unclear. A prospective study was developed to explore the effects of somatostatin on gut microbiota and we aim to identify the microbial alterations in the process of POPF. A total of 45 patients were randomly divided into PD group or additional somatostatin therapy group. The fecal sample of each patient was collected preoperatively and postoperatively and the gut microbiota was analyzed by 16S rRNA sequencing. Our study found that somatostatin therapy was independent risk factor for the occurrence of POPF, and it reduced the microbial diversity and richness in patients. At genus level, somatostatin therapy led to a decreased abundance in Bifidobacterium, Subdoligranulum and Dubosiella, whereas the abundance of Akkermansia, Enterococcus and Enterobacter were increased. The abundance levels of certain bacteria in the gut microbiota have significantly shifted in patients with POPF. The LEfSe analysis revealed that Ruminococcaceae could be used as microbial markers for distinguishing patients with high risk of POPF. Furthermore, Verrucomicrobia and Akkermansia could be used as preoperative biomarkers for identifying patients without POPF. Our prospective study highlights the specific communities related with somatostatin therapy and discovers POPF-associated microbial marker, which suggests that gut microbiota may become a diagnostic biomarker and potential therapeutic target for POPF.

Correction: Gut microbiota patterns associated with somatostatin in patients undergoing pancreaticoduodenectomy: a prospective study.

[This corrects the article DOI: 10.1038/s41420-020-00329-4.].

HYAL-1-induced autophagy facilitates pancreatic fistula for patients who underwent pancreaticoduodenectomy.

The main mechanism of hyaluronidase 1(HYAL-1) in the development of postoperative pancreatic fistula (POPF) after pancreatoduodenectomy (PD) was unknown. In this study, a comprehensive inventory of pre-, intra-, and postoperative clinical and biological data of two cohorts (62 pancreatic cancer [PCa] and 111 pancreatic ductal adenocarcinoma [PDAC]) which could induce POPF were retrospectively analyzed. Then, a total of 7644 genes correlated with HYAL-1 was predicted in PDAC tissues and the enriched pathway, kinase targets and biological process of those correlated genes were evaluated. Finally, a mouse pancreatic fistula (PF) model was first built and in vitro studies were performed to investigate the effects of HYAL-1 on PF progression. Our data indicated that preoperative serum HYAL-1 level, pancreatic fibrosis score, and pancreatic duct size were valuable factors for detecting POPF of Grade B and C. The serum HYAL-1 level of 2.07 mg/ml and pancreatic fibrosis score of 2.5 were proposed as the cutoff values for indicating POPF. The bioinformatic analysis and in vitro and in vivo studies demonstrated that HYAL-1 facilitates pancreatic acinar cell autophagy via the dephosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK) and signal transducers and activators of transcription 3 (STAT3) signaling pathways, which exacerbate pancreatic secretion and inflammation. In summary, the preoperative serum HYAL-1 was a significant predictor for POPF in patients who underwent PD. Tumor-induced HYAL-1 is one of core risk in accelerating PF and then promoting pancreatic secretion and acute inflammation response through the AMPK and STAT3-induced autophagy.

LncSHRG promotes hepatocellular carcinoma progression by activating HES6.

Hepatocellular carcinoma, one of the most common cancers, leads to mass mortality worldwide currently. However, the underlying mechanism of its oncogenesis remains to be elucidated. Here we identified that a long noncoding RNA, lncSHRG, was greatly upregulated in human hepatocellular carcinoma samples. We found that lncSHRG was essential for liver cancer cell proliferation and tumor propagation in mice. In mechanism, lncSHRG recruits SATB1 to bind to HES6 promoter and initiates HES6 expression. HES6, which is highly expressed in hepatocellular carcinoma, promotes tumor cell proliferation. High expression level of HES6 is positively correlated with clinical severity and poor prognosis of people with hepatocellular carcinoma. Altogether, our research provides a new insight on the mechanism of hepatocellular carcinoma progression.