Visceral adipocyte-derived extracellular vesicle miR-27a-5p elicits glucose intolerance by inhibiting pancreatic ß-cell insulin secretion.

Pancreatic ß-cell dysfunction caused by obesity can be associated with alterations in the levels of microRNAs (miRNAs). However, the role of miRNAs in such processes remains elusive. Here, we show that pancreatic islet miR-27a-5p, which is markedly increased in obese mice and impairs insulin secretion, is mainly delivered by visceral adipocyte-derived extracellular vesicles (EVs). Depleting miR-27a-5p significantly improves insulin secretion and glucose intolerance in db/db mice. Supporting the function of EVs' miR-27a-5p as a key pathogenic factor, intravenous injection of miR-27a-5p-containing EVs shows their distribution in mouse pancreatic islets. Tracing the injected AAV-miR-27a-5p (AAV-miR-27a) or AAV-FABP4-miR-27a-5p (AAV-FABP4-miR-27a) in visceral fat results in upregulating miR-27a-5p in EVs and serum, and elicits mouse pancreatic ß-cell dysfunction. Mechanistically, miR-27a-5p directly targets L-type Ca2+ channel subtype CaV1.2 (Cacna1c) and reduces insulin secretion in ß-cells. Overexpressing mouse CaV1.2 largely abolishes the insulin secretion injury induced by miR-27a-5p. These findings reveal a causative role of EVs' miR-27a-5p in visceral adipocyte-mediated pancreatic ß-cell dysfunction in obesity-associated type 2 diabetes mellitus.

Development of a quantum dot-based lateral flow immunoassay strip for rapid and sensitive detection of SARS-CoV-2 neutralizing antibodies.

To a certain extent, the development and vaccination of COVID-19 vaccine have reduced the alarming rate of transmission speed and mortality rate. At present, vaccine coverage is quite high in countries around the world. Since individual differences are unavoidable, it is necessary to assess the efficacy of the vaccine in each vaccinated person in order to reflect the protective effect of the vaccine in different populations. In this study, we developed a novel COVID-19 neutralizing antibody detection kit combining lateral flow immunochromatography and novel quantum dot technology with 85.23% sensitivity, 92.50% specificity. The novel QD-ICA could achieve an accurate detection of SARS-CoV-2 neutralizing antibodies with 10 minutes, two steps, small equipment size, and broad testing application, suggesting its capability to assess vaccine effectiveness on a large scale in areas of world that currently affected by the pandemic.

Recent advances in enrichment, isolation, and bio-electrochemical activity evaluation of exoelectrogenic microorganisms.

Exoelectrogenic microorganisms (EEMs) catalyzed the conversion of chemical energy to electrical energy via extracellular electron transfer (EET) mechanisms, which underlay diverse bio-electrochemical systems (BES) applications in clean energy development, environment and health monitoring, wearable/implantable devices powering, and sustainable chemicals production, thereby attracting increasing attentions from academic and industrial communities in the recent decades. However, knowledge of EEMs is still in its infancy as only ∼100 EEMs of bacteria, archaea, and eukaryotes have been identified, motivating the screening and capture of new EEMs. This review presents a systematic summarization on EEM screening technologies in terms of enrichment, isolation, and bio-electrochemical activity evaluation. We first generalize the distribution characteristics of known EEMs, which provide a basis for EEM screening. Then, we summarize EET mechanisms and the principles underlying various technological approaches to the enrichment, isolation, and bio-electrochemical activity of EEMs, in which a comprehensive analysis of the applicability, accuracy, and efficiency of each technology is reviewed. Finally, we provide a future perspective on EEM screening and bio-electrochemical activity evaluation by focusing on (i) novel EET mechanisms for developing the next-generation EEM screening technologies, and (ii) integration of meta-omics approaches and bioinformatics analyses to explore nonculturable EEMs. This review promotes the development of advanced technologies to capture new EEMs.

TRIM21 ameliorates hepatic glucose and lipid metabolic disorders in type 2 diabetes mellitus by ubiquitination of PEPCK1 and FASN.

Hepatic glucose and lipid metabolism disorders promote the development and progression of type 2 diabetes mellitus (T2DM), yet the underlying mechanisms are not fully understood. Here, we identify tripartite motif-containing protein 21 (TRIM21), a class IV TRIM family member, as a pivotal regulator of hepatic metabolism in T2DM for the first time. Bioinformatic analysis suggests that TRIM21 expression is significantly reduced in T2DM patients. Intriguingly, in a mouse model of obese diabetes, TRIM21 expression is predominantly reduced in the liver rather than in other metabolic organs. It is further demonstrated that hepatic overexpression of TRIM21 significantly ameliorates glucose intolerance, insulin resistance, hepatic steatosis, and dyslipidemia in obese diabetic mice. In contrast, the knockdown of TRIM21 promotes glucose intolerance, insulin resistance, and triglyceride accumulation. Mechanistically, both phosphoenolpyruvate carboxykinase 1 (PEPCK1) and fatty acid synthase (FASN) are the hepatic targets of TRIM21. We revealed that TRIM21 promotes the degradation of PEPCK1 and FASN through a direct protein-protein interaction mediated K48-linked ubiquitination. Notably, overexpression of PEPCK1 and FASN essentially abolished the beneficial effects achieved by TRIM21 overexpression in obese diabetic mice. Overall, our data demonstrate that TRIM21 is a novel regulator of hepatic metabolic disorder, and suggest TRIM21 as a promising therapeutic target for T2DM.

Inflammatory Response, a Key Pathophysiological Mechanism of Obesity-Induced Depression.

In recent years, with the acceleration of life rhythm and the increase of social competition, the incidence of obesity and depression has been increasing, which has seriously affected the quality of life and health of people. Obesity and depression, two seemingly unrelated physical and psychological diseases, in fact, are closely related: obese people are more likely to have depression than nonobese ones. We have reviewed and analyzed the relevant research literature and found that the inflammatory response plays a key role in obesity-induced depression. This article will discuss in detail the inflammatory mechanisms by which obesity induces depression.

Transcriptomic Analysis of the Influence of Methanol Assimilation on the Gene Expression in the Recombinant Pichia pastoris Producing Hirudin Variant 3.

Hirudin and its variants, as strong inhibitors against thrombin, are present in the saliva of leeches and are recognized as potent anticoagulants. However, their yield is far from the clinical requirement up to now. In this study, the production of hirudin variant 3 (HV3) was successfully realized by cultivating the recombinant Pichia pastoris GS115/pPIC9K-hv3 under the regulation of the promoter of AOX1 encoding alcohol oxidase (AOX). The antithrombin activity in the fermentation broth reached the maximum value of 5000 ATU/mL. To explore an effective strategy for improving HV3 production in the future, we investigated the influence of methanol assimilation on the general gene expression in this recombinant by transcriptomic study. The results showed that methanol was partially oxidized into CO2, and the rest was converted into glycerone-P which subsequently entered into central carbon metabolism, energy metabolism, and amino acid biosynthesis. However, the later metabolic processes were almost all down-regulated. Therefore, we propose that the up-regulated central carbon metabolism, energy, and amino acid metabolism should be beneficial for methanol assimilation, which would accordingly improve the production of HV3.

Biochemical characterization of a novel GH43 family ß-xylosidase from Bacillus pumilus.

Although ß-xylosidases have a wide range of applications, cold-active ß-xylosidases have been poorly studied. In this study, a cold active ß-xylosidase gene (xyl) from Bacillus pumilus TCCC 11,350 was cloned and overexpressed in Escherichia coli. The recombinant XYL (rXYL) was revealed to be a bifunctional enzyme with both ß-xylosidase and α-l-arabinofuranosidase activities. Purified rXYL was most active at 30 °C, demonstrating 26% and 18% of its maximum activity at 4 °C and 0 °C, respectively. Meanwhile, rXYL showed a 52% activity in 200 mM xylose, indicating a relatively strong tolerance to xylose. Moreover, rXYL exhibited a high synergistic effect (11.14-fold and 16.21-fold) with endo-xylanase to degrade beechwood xylan in both sequential and simultaneous reactions at low temperatures. As the first report on the novel cold-adapted ß-xylosidase from B. pumilus, these results suggested rXYL had attractive properties for food industrial utilizations.

Improvement of the alkali stability of Penicillium cyclopium lipase by error-prone PCR

BACKGROUND: Lipases are extensively exploited in lots of industrial fields; cold-adapted lipases with alkali-resistance are especially desired in detergent industry. Penicillium cyclopium lipase I (PCL) might be suitable for applications of detergent industry due to its high catalytic efficiency at low temperature and relatively good alkali stability. In this study, to better meet the requirements, the alkali stability of PCL was further improved via directed evolution with error-prone PCR. RESULTS: The mutant PCL (N157F) with an improved alkali stability was selected based on a high-throughput activity assay. After incubating at pH 11.0 for 120 min, N157F retained 70% of its initial activity, which was 23% higher than that of wild type PCL. Combined with the three-dimensional structure analysis, N157F exhibited an improved alkali stability under the high pH condition due to the interactions of hydrophilicity and ß-strand propensity. Conclusions: This work provided the theoretical foundation and preliminary data for improving alkali stability of PCL to meet the industrial requirements, which is also beneficial to improving alkali-tolerance ability of other industrial enzymes via molecular modification.

Clinical Parameters and Gut Microbiome Changes Before and After Surgery in Thoracic Aortic Dissection in Patients with Gastrointestinal Complications.

Thoracic aortic dissection (TAAD) is one of the most common types of aortic diseases. Although surgery remains the main method of treatment, the high rate of postoperative gastrointestinal complications significantly influences the effects of surgery and the recovery process. Moreover, the mechanisms underlying this disease remain unclear. To address these problems, we examined changes in the gut microbiota in 40 thoracic aortic dissection patients with abdominal complications after surgery. Levels of white blood cells (WBC), neutrophile granulocytes (NE), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were higher in all patients after surgery. Levels of inflammatory cytokines, including interleukin (IL)-2, IL-6, IL-8, and IL-10, were also higher after surgery. A metagenome analysis revealed that levels of Oscillibacter, Anaerotruncus, Alistipes, and Clostridium difficile were higher after the operation. The abundance of functional genes, such as the spermidine/putrescine transport system permease protein, the flagellar motor switch protein, and branched-chain amino acid transport system proteins, was also higher post-surgery. These changes likely contribute to diarrhea, bloating, gastrointestinal bleeding, and other abdominal complications after surgery, and our research opens up new treatment possibilities for patients suffering from abdominal complications after surgical treatment.