Corn stigma ameliorates hyperglycemia in zebrafish and GK rats of type 2 diabetes.

ETHNOPHARMACOLOGICAL RELEVANCE: Cornstigma (CS), derived from the stigma and style of gramineous plant Zeamays. The medicinal use of CS can be traced back to DianNanMateriaMedica. LingnanMedicinalPlantsCompendium records its effectiveness in ameliorating diabetes. Diabetes is a metabolic disorder characterized by hyperglycemia and the consequent chronic complications of kidney, heart, brain and other organs, which pose a significant threat to human health. CS has shown great potential in relieving hyperglycemia associated with diabetes. However, the mechanism of CS in treating diabetes remains unclear. AIM OF THE STUDY: To explore the pathogenesis of diabetes and the mechanism of CS improving hyperglycemia in diabetes. MATERIALS AND METHODS: We measured apigenin and luteolin contents in CS by UPLC/MS/MS method. Selecting Wistar rats as normal group, and GK rats as model group. For rats, we detected glucose and lipid metabolism indicators, including GHb, AST, ALT, U-Glu, UA, U-TP, U-ALB, and ACR after treatment. For zebrafish, we utilized alloxan and sucrose to establish the diabetes model. Measuring zebrafish blood glucose is employed to evaluate the hypoglycemic capability of CS. In order to explore the mechanism of CS in treating diabetes, we sequenced the transcriptome of zebrafish, compared differentially expressed genes of normal, diabetic, and CS-treated group, and validated multiple enrichment pathways by PCR. RESULTS: CS can improve blood glucose levels in both GK rats and diabetic zebrafish. For rats, CS partially restored glucose and lipid metabolism indicators. Transcriptome data from zebrafish showed a close correlation with steroid biosynthesis. The RNA-Sequencing was consistent with PCR results, indicating that CS downregulated gene (fdft1,lss,cyp51) expression concerned with steroid biosynthesis pathway in the diabetes model. CONCLUSION: CS effectively improved blood glucose levels, regulated glucose and lipid metabolism by suppressing gene expression in steroid biosynthesis pathway, and ameliorated hyperglycemia. Our research provides valuable insights for CS in the treatment of diabetes, and proposes a new strategy for selecting clinical medications for diabetes.

SARS-CoV-2 ORF7a blocked autophagy flux by intervening in the fusion between autophagosome and lysosome to promote viral infection and pathogenesis.

The coronavirus disease 2019 (COVID-19) continues to pose a major threat to public health worldwide. Although many studies have clarified the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection process, the underlying mechanisms of viral invasion and immune evasion were still unclear. This study focused on SARS-CoV-2 ORF7a (open reading frame-7a), one of the essential open reading frames (ORFs) in infection and pathogenesis. First, by analyzing its physical and chemical characteristics, SARS-CoV-2 ORF7a is an unstable hydrophobic transmembrane protein. Then, the ORF7a transmembrane domain three-dimensional crystal structure model was predicted and verified. SARS-CoV-2 ORF7a localized in the endoplasmic reticulum and participated in the autophagy-lysosome pathway via interacting with p62. In addition, we elucidated the underlying molecular mechanisms by which ORF7a intercepted autophagic flux, promoted double membrane vesicle formation, and evaded host autophagy-lysosome degradation and antiviral innate immunity. This study demonstrated that ORF7a could be a therapeutic target, and Glecaprevir may be a potential drug against SARS-CoV-2 by targeting ORF7a. A comprehensive understanding of ORF7a's functions may contribute to developing novel therapies and clinical drugs against COVID-19.

External Application of Human Umbilical Cord-Derived Mesenchymal Stem Cells in Hyaluronic Acid Gel Repairs Foot Wounds of Types I and II Diabetic Rats Through Paracrine Action Mode.

Diabetic foot ulcer (DFU) is a main diabetic complication with unmet treatment needs. This study applied human umbilical cord-derived mesenchymal stem cells-hyaluronic acid (hucMSCs-HA) gel to treat DFU in a noninvasive external way and investigated its paracrine action and mechanism. In this study, after analyzing the physical and biological properties of HA gel, hucMSCs-HA gel was applied in 2 in vivo models (types I and II DFU), and a molecular mechanism was investigated. To evaluate the paracrine action of hucMSCs, hucMSCs-conditional medium (MSC-CM) was collected to treat 1 in vivo model (type I DFU) and 2 in vitro models (high glucose (HG)-injured human umbilical vein endothelial cells (HUVECs) and human skin fibroblasts (HSFs)). The results indicated that HA gel with a porous microstructure underwent over 90% degradation and swelled to the maximum value within 48 h. In vivo, hucMSCs-HA gel accelerated wound healing of DFU rats by improving re-epithelialization, collagen deposition, and angiogenesis, in which a paracrine action of hucMSCs was confirmed and the phosphorylation of p38, ERK1/2, JNK, and Akt was increased. In vitro, MSC-CM improved cell viability, wound healing, migration, tube formation, cell senescence, and abnormal expressions (TNF-α, IL-1ß, IL-6, ET-1, p16 genes, and PCNA protein) of HUVECs, also improved cell viability, wound healing, antioxidant stress, and abnormal expressions (COL1, COL3, COL4, SOD1, SOD2 genes, and PCNA protein) of HSFs. Summarily, noninvasive external application of hucMSCs-HA gel shows great perspective against DFU and exerts wound healing effects through the MAPK and Akt pathways-mediated paracrine mechanism.

Intravenous injection of human umbilical cord-derived mesenchymal stem cells ameliorates not only blood glucose but also nephrotic complication of diabetic rats through autophagy-mediated anti-senescent mechanism.

BACKGROUND: Diabetic nephropathy (DN) is one of the most severe complications of diabetes mellitus, which is characterized by early occurrence of albuminuria and end-stage glomerulosclerosis. Senescence and autophagy of podocytes play an important role in DN development. Human umbilical cord-derived mesenchymal stem cells (hucMSCs) have potential in the treatment of diabetes and its complications. However, the role of hucMSCs in the treatment of DN and the underlying mechanism remain unclear. METHODS: In vivo, a streptozotocin-induced diabetic male Sprague Dawley rat model was established to determine the renoprotective effect of hucMSCs on DN by biochemical analysis, histopathology, and immunohistochemical staining of renal tissues. And the distribution of hucMSCs in various organs in rats within 168 h was analyzed. In vitro, CCK8 assay, wound healing assay, and ß-galactosidase staining were conducted to detect the beneficial effects of hucMSCs on high glucose-induced rat podocytes. Real-time PCR and western blot assays were applied to explore the mechanism of action of hucMSCs. RESULTS: The in vivo data revealed that hucMSCs were distributed into kidneys and significantly protected kidneys from diabetic damage. The in vitro data indicated that hucMSCs improved cell viability, wound healing, senescence of the high glucose-damaged rat podocytes through a paracrine action mode. Besides, the altered expressions of senescence-associated genes (p16, p53, and p21) and autophagy-associated genes (Beclin-1, p62, and LC3) were improved by hucMSCs. Mechanistically, hucMSCs protected high glucose-induced injury in rat podocytes by activating autophagy and attenuating senescence through the AMPK/mTOR pathway. CONCLUSIONS: In conclusion, hucMSCs might be a promising therapeutic strategy for the clinical treatment of DN-induced renal damages.

A database of animal metagenomes.

With the rapid development of high-throughput sequencing technology, the amount of metagenomic data (including both 16S and whole-genome sequencing data) in public repositories is increasing exponentially. However, owing to the large and decentralized nature of the data, it is still difficult for users to mine, compare, and analyze the data. The animal metagenome database (AnimalMetagenome DB) integrates metagenomic sequencing data with host information, making it easier for users to find data of interest. The AnimalMetagenome DB is designed to contain all public metagenomic data from animals, and the data are divided into domestic and wild animal categories. Users can browse, search, and download animal metagenomic data of interest based on different attributes of the metadata such as animal species, sample site, study purpose, and DNA extraction method. The AnimalMetagenome DB version 1.0 includes metadata for 82,097 metagenomes from 4 domestic animals (pigs, bovines, horses, and sheep) and 540 wild animals. These metagenomes cover 15 years of experiments, 73 countries, 1,044 studies, 63,214 amplicon sequencing data, and 10,672 whole genome sequencing data. All data in the database are hosted and available in figshare https://doi.org/10.6084/m9.figshare.19728619 .

Human umbilical cord-derived mesenchymal stem cells not only ameliorate blood glucose but also protect vascular endothelium from diabetic damage through a paracrine mechanism mediated by MAPK/ERK signaling.

BACKGROUND: Endothelial damage is an initial step of macro- and micro-vasculature dysfunctions in diabetic patients, accounting for a high incidence of diabetic vascular complications, such as atherosclerosis, nephropathy, retinopathy, and neuropathy. However, clinic lacks effective therapeutics targeting diabetic vascular complications. In field of regenerative medicine, mesenchymal stem cells, such as human umbilical cord-derived MSCs (hucMSCs), have great potential in treating tissue damage. METHODS: To determine whether hucMSCs infusion could repair diabetic vascular endothelial damage and how it works, this study conducted in vivo experiment on streptozotocin-induced diabetic rat model to test body weight, fasting blood glucose (FBG), serum ICAM-1 and VCAM-1 levels, histopathology and immunohistochemical staining of aorta segments. In vitro experiment was further conducted to determine the effects of hucMSCs on diabetic vascular endothelial damage, applying assays of resazurin staining, MTT cell viability, wound healing, transwell migration, and matrigel tube formation on human umbilical vein endothelial cells (HUVECs). RNA sequencing (RNAseq) and molecular experiment were conducted to clarify the mechanism of hucMSCs. RESULTS: The in vivo data revealed that hucMSCs partially restore the alterations of body weight, FBG, serum ICAM-1 and VCAM-1 levels, histopathology of aorta and reversed the abnormal phosphorylation of ERK in diabetic rats. By using the conditioned medium of hucMSCs (MSC-CM), the in vitro data revealed that hucMSCs improved cell viability, wound healing, migration and angiogenesis of the high glucose-damaged HUVECs through a paracrine action mode, and the altered gene expressions of IL-6, TNF-α, ICAM-1, VCAM-1, BAX, P16, P53 and ET-1 were significantly restored by MSC-CM. RNAseq incorporated with real-time PCR and Western blot results clarified that high glucose activated MAPK/ERK signaling in HUVECs, while MSC-CM reversed the abnormal phosphorylation of ERK and overexpressions of MKNK2, ERBB3, MYC and DUSP5 in MAPK/ERK signaling pathway. CONCLUSIONS: HucMSCs not only ameliorated blood glucose but also protected vascular endothelium from diabetic damage, in which MAPK/ERK signaling mediated its molecular mechanism of paracrine action. Our findings provided novel knowledge of hucMSCs in the treatment of diabetes and suggested a prospective strategy for the clinical treatment of diabetic vascular complications.

Coronavirus Usurps the Autophagy-Lysosome Pathway and Induces Membranes Rearrangement for Infection and Pathogenesis.

Autophagy is a crucial and conserved homeostatic mechanism for early defense against viral infections. Recent studies indicate that coronaviruses (CoVs) have evolved various strategies to evade the autophagy-lysosome pathway. In this minireview, we describe the source of double-membrane vesicles during CoV infection, which creates a microenvironment that promotes viral RNA replication and virion synthesis and protects the viral genome from detection by the host. Firstly, CoVs hijack autophagy initiation through non-structural proteins and open-reading frames, leading to the use of non-nucleated phagophores and omegasomes for autophagy-derived double-membrane vesicles. Contrastingly, membrane rearrangement by hijacking ER-associated degradation machinery to form ER-derived double-membrane vesicles independent from the typical autophagy process is another important routine for the production of double-membrane vesicles. Furthermore, we summarize the molecular mechanisms by which CoV non-structural proteins and open-reading frames are used to intercept autophagic flux and thereby evade host clearance and innate immunity. A comprehensive understanding of the above mechanisms may contribute to developing novel therapies and clinical drugs against coronavirus disease 2019 (COVID-19) in the future.

Acute glucose fluctuation promotes RAGE expression via reactive oxygen species­mediated NF­κB activation in rat podocytes.

Diabetic nephropathy (DN) is a common chronic complication of diabetes, for which acute glucose fluctuation (AGF) is a potential risk factor. Fluctuating hyperglycemia has been confirmed to induce more serious kidney damage than hyperglycemia in diabetic rats; however, the mechanism remains unknown. The purpose of this study was to explore the potential role of AGF in the progression of DN. Viability of rat podocytes following 72­h AGF treatment was detected using Cell Counting­Kit­8. The rates of apoptosis and the level of reactive oxygen species (ROS) in rat podocytes were assessed by flow cytometry. Western blotting and reverse transcription­quantitative PCR were performed to measure relative protein and mRNA expression levels, respectively. Transfection with an mRFP­GFP­LC3 adenoviral vector was used to track autophagic flux under confocal microscopy. The results indicated that AGF could inhibit cell proliferation, promote TNF­α, interleukin­1ß (IL­1ß), and reactive oxygen species (ROS) generation, and increase autophagy in rat podocytes. Moreover, AGF upregulated receptor for advanced glycation end products (RAGE) expression via activation of NF­κB/p65 and IκBα. Pretreatment with 5 mM N­Acetyl­L­cysteine or 10 µM pyrrolidine dithiocarbamate effectively reduced cellular damage and inhibited activation of the NF­κB/RAGE signaling pathway. Thus, AGF induces rat podocyte injury by aggravating oxidative stress, promoting the inflammatory response, and regulating ROS­mediated NF­κB/RAGE activation.

Formononetin protects against concanavalin-A-induced autoimmune hepatitis in mice through its anti-apoptotic and anti-inflammatory properties.

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease that seriously threatens the health of humans globally. Formononetin (FMN) is a natural herb extract with multiple biological functions. In this study, an experimental model of AIH was established in mice through the use of concanavalin A (ConA). To investigate the effects of FMN on ConA-induced hepatitis, the mice were pretreated with 50 or 100 mg/kg body mass of FMN. The results show that FMN alleviated ConA-induced liver injury of mice in a dose-dependent manner. Moreover, pretreatment with FMN inhibited the apoptosis of hepatocytes in the ConA-treated mice through downregulating the expression of pro-apoptotic proteins (Bax, cleaved caspase 9, and cleaved caspase 3) and upregulating the expression of anti-apoptotic protein (Bcl-2). It was also found that the levels of proinflammatory cytokines were greatly reduced in the serum and liver tissues of mice pretreated with FMN. Further studies showed that FMN reduced the level of phosphorylated nuclear factor kappa B (p-NF-κB) p65 and enhanced the level of IκBα (inhibitor of NF-κB), suggesting that FMN inhibits the activation of the NF-κB signaling pathway. In addition, FMN inhibited activation of the NOD-like receptor protein 3 (NLRP3) inflammasome. Therefore, FMN could be a promising agent for the treatment of AIH.