High Glucose Medium Research Articles

Daphnetin Protects Schwann Cells Against High-Glucose-Induced Oxidative Injury by Modulating the Nuclear Factor Erythroid 2-Related Factor 2/Glutamate-Cysteine Ligase Catalytic Subunit Signaling Pathway.

Diabetic peripheral neuropathy (DPN), a common complication of diabetes mellitus, is primarily characterized by damage to Schwann cells caused by oxidative stress under hyperglycemic conditions. Recently, we demonstrated the ability of coumarin-rich Ficus formosana Maxim. to alleviate DPN in ovariectomized diabetic mice. However, the underlying mechanisms remain unclear. In this study, we established an in vitro DPN model using RSC96 Schwann cells exposed to high glucose levels. Daphnetin, a natural coumarin found abundantly in Ficus formosana Maxim., was co-incubated with Schwann cells in a high-glucose medium to investigate its protective effects against DPN. The free radical scavenging capacity of daphnetin was evaluated, along with assessments of cell viability, apoptosis, H2O2 levels, and the expression of proteins by the nuclear factor erythroid 2-related factor 2 (Nrf2)/glutamate-cysteine ligase catalytic subunit (GCLC) pathway in RSC96 Schwann cells. The results showed that daphnetin was non-toxic within the tested concentration range of 6.25 μM to 50 μM in RSC96 Schwann cells. Moreover, daphnetin significantly improved cell viability, exhibited strong antioxidant activity, reduced H2O2 levels, and regulated the Nrf2/GCLC pathway protein expressions in RSC96 cells cultured in high-glucose medium. Additionally, daphnetin influenced apoptosis-related proteins by decreasing the expression levels of Bax and Caspase 3, while increasing the Bcl-2 expression level in high-glucose-treated RSC96 cells. These findings suggest that daphnetin may alleviate oxidative stress induced by high glucose levels through activation of the Nrf2/GCLC pathway and inhibition of Schwann cell apoptosis, underscoring its potential as a therapeutic agent for DPN.

Mitochondrial toxicity of selected natural compounds: in vitro assessment and in silico molecular docking and dynamics simulation

Prangos uechtritzii Boiss & Hausskn stands out for its rich bioactive constituents including prantschimgin (PRA), imperatorin (IMP), suberosin (SUB), adicardin (ADI), and oxypeucedanin hydrate (OPH) in the Apiaceae family. Although these molecules contribute to several biological activities, their mitochondrial toxicity were not illuminated in depth with the appropriate in vitro and in silico models. Cell viability studies investigated the cytotoxic activities of molecules in HepG2 cells by replacing glucose with galactose due to Warburg effects. Mitochondrial toxicity (mitotoxicity) parameters such as cellular adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP) levels were assessed with cytotoxic concentrations of selected molecules. Molecular docking and dynamics studies were also conducted against mitochondrial electron transport chain (ETC) complexes (I-V) with selected compounds. In vitro results showed that PRA, SUB, and IMP reduced cell viability more in galactose media compared to high glucose media in a dose-dependent manner. PRA, IMP, and SUB decreased ATP levels and MMP, especially in the galactose medium. The in silico study revealed that PRA, IMP, and SUB might bind to complexes I-V at different levels. The docking study demonstrated that PRA had the highest binding potential with the complexes, higher than the standard ligands in some cases. The molecular dynamics (MD) simulation study showed that PRA formed stable complexes with complexes II, III, and IV. In addition, PRA was anticipated to remain inside the binding site of complex II most stably during the 230 ns simulation period. Our study suggests that PRA, IMP, and SUB exhibit mitotoxicity.

Coffee Bioactive N-Methylpyridinium: Unveiling Its Antilipogenic Effects by Targeting De Novo Lipogenesis in Human Hepatocytes.

Type 2 diabetes and nonalcoholic fatty liver diseases (NAFLDs) are promoted by insulin resistance (IR), which alters lipid homeostasis in the liver. This study aims to investigate the effect of N-methylpyridinium (NMP), a bioactive alkaloid of coffee brew, on lipid metabolism in hepatocytes. The effect of NMP in modulating lipid metabolism is evaluated at physiological concentrations in a diabetes cell model represented by HepG2 cells cultured in a high-glucose medium. Hyperglycemia triggers lipid droplet accumulation in cells and enhances the lipogenic gene expression, which is transactivated by sterol regulatory element binding protein-1 (SREBP-1). Lipid droplet accumulation alters the redox status and endoplasmic reticulum (ER) stress, leading to the activation of the unfolded protein response and antioxidative pathways by X-Box Binding Protein 1(XBP-1)/eukaryotic Initiation Factor 2 alpha (eIF2α) Protein Kinase RNA-Like ER Kinase and nuclear factor erythroid 2-related factor 2 (NRF2), respectively. NMP induces the phosphorylation of AMP-dependent protein kinase (AMPK) and acetyl-CoA carboxylase α (ACACA), and improves the redox status and ER homeostasis, essential steps to reduce lipogenesis and lipid droplet accumulation. These results suggest that NMP may be beneficial for the management of T2D and NAFLD by ameliorating the cell oxidative and ER homeostasis and lipid metabolism.

Alpha(α)-mangostin (Xanthone of Garcinia mangostana L.): Augmenting Macrophages Activity for an Effective Diabetic Wound Healing

Diabetic wounds are particularly difficult to treat medically because they heal at a slower pace than regular wounds. Macrophages are essential in all stages of normal wound healing, including inflammation, proliferation and rem odelling. When wound healing is affected, macrophages can reduce the level of growth factor and increase the level of interleukin-6 (IL-6), disrupt the balance between tissue inhibitors of metalloproteinase (TIMPs) and matrix metalloproteinase (MMPs), which can slow down healing. Alpha(α)-mangostin, a natural xanthone derived from the pericarp of the mangosteen, has gained considerable attention due to its anti-inflammatory properties, suggesting its potential to promote wound healing. However, its exact role in healing diabetic foot ulcers, common in diabetes, remains unclear. Hence, this study aims to explore how α-mangostin might affect diabetic wound healing by evaluating its impact on PDGF, CTGF, BFGF, VEGF, TGF-β, MMP-9, TIMP-2 and IL-6 secretion in macrophage cells. Human monocytic macrophages (THP-1) were incubated with a 35 mM glucose solution for 72 h to create a glucose-enriched medium. The cells were then incubated with α-mangostin (0.15, 2.5 and 5 µg/mL) together with 35 mM glucose. Carboxymethyl cellulose (CMC) served as positive controls; glucose-enriched media and media-alone served as negative controls. Protein expression was measured using ELISA. α-mangostin (2.5 µg/mL) increased the levels of PDGF and VEGF and decreased the level of MMP-9 compared to glucose controls. There was no significant difference in other growth factors, TIMP-2 and IL-6 protein levels across any of the treatment groups compared to glucose controls. In conclusion, α-mangostin particularly at 2.5 µg/mL demonstrated a significant increase in PDGF and VEGF levels while simultaneously reducing MMP-9 in macrophage cells under glucose-induced conditions. These findings suggest that α-mangostin holds the potential for enhancing the healing of chronic wounds in diabetic conditions. HIGHLIGHTS Treatment of macrophages (THP-1 cells) with 2.5 µg/mL Alpha (α)-mangostin in a high glucose medium led to a significant increase in PDGF and VEGF secretion compared to glucose control. Treatment of the cells with 2.5 µg/mL Alpha (α)-mangostin in a high glucose medium led to a significant reduction of MMP-9 secretion compared to glucose control. There is no significant effects of Alpha (α)-mangostin on IL-6 and TIMP secretion compared to controls This study suggests that Alpha (α)-mangostin may be beneficial in promoting diabetic wound healing via stimulation of PDGF and VEGF secretion and reducing MMP-9 levels. GRAPHICAL ABSTRACT

Determination of beneficial effects of cuminaldehyde on hyperglycemiaassociated kidney malfunctions.

Type 1 diabetes mellitus is defined by the autoimmune destruction of pancreatic β cells, with diabetic nephropathy being a significant consequence. Recently, cuminaldehyde has been shown protective ability against various pathophysiology. However, its nephroprotective and anti-diabetic potential has not yet been fully understood. We, therefore, conducted the present study to evaluate the anti-hyperglycemic potential of cuminaldehyde in NRK52E cells without (control) or with high glucose medium to emulate hyperglycemic conditions. Cuminaldehyde pre-treatment at an optimal concentration of 175μM prior to high glucose addition restricted excessive reactive oxygen species (ROS) production and maintained cellular morphology to almost normal. The inhibitor study using N-acetyl-l-cysteine confirmed that blocking of ROS assists NRK52E cells in evading apoptosis. In addition, hyperglycemia was induced in 6-week-old Swiss albino mice in this investigation through the intraperitoneal injection of streptozotocin (150mgkg-1 body weight). Hyperglycemia increased the kidney-to-body weight ratio, lowered serum insulin levels, and led to significant renal tissue damage compared to control mice. Moreover, hyperglycemia disturbs cellular redox equilibrium by decreasing antioxidant enzyme functions and promoting inflammatory cytokines in kidney tissue. Administering cuminaldehyde at a dosage of 10mgkg-1 body weight for 5weeks daily after the onset of diabetes effectively ameliorated the aforementioned anomalies and reversed kidney damage by regulating inflammation-induced cell death. Overall, the research demonstrated that cuminaldehyde has hypoglycemic, antioxidant, anti-inflammatory, and anti-apoptotic properties. We believe that after conducting extensive research, this unique molecule can be used in clinical trials against diabetic nephropathy in future.

TAK-242 alleviates diabetic cardiomyopathy via inhibiting pyroptosis and TLR4/CaMKII/NLRP3 pathway.

Diabetic cardiomyopathy (DCM) is identified as a progressive disease that may lead to irreparable heart failure. Toll-like receptor (TLR) signaling is believed to be implicated in the pathogenesis of DCM. This study intended to explore the potential impact of Toll-like receptor 4 (TLR4) on DCM in vitro and in vivo. Streptozotocin and HG medium were utilized to induce diabetes in animal and cell models, respectively. Selective TLR4 inhibitor TAK-242 and calcium/calmodulin-dependent protein kinase-II (CaMKII) inhibitor KN-93 were employed to explore the involvement of TLR4/CaMKII in DCM. TLR4 expression was increased in DCM hearts, while inhibition of TLR4 activation by TAK-242 improved cardiac function, attenuated heart hypertrophy, and fibrosis, as well as reduced oxidative stress and proinflammatory cytokine levels in rats, which were confirmed by Doppler echocardiography, hematoxylin and eosin staining, and Masson Trichome staining and specific enzyme-linked immunosorbent assay kits. Besides, the expression of hypertrophy-related molecules and oxidative stress damage were also inhibited by TAK-242. Furthermore, TAK-242 treatment reduced CaMKII phosphorylation accompanied by decreased expression of NOD-like pyrin domain-containing protein 3, gasdermin D (GSDMD), The N-terminal domain of Gasdermin D (GSDMD-N), apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) and Caspase-1 both in vivo and in vitro. Similar positive impacts on HG-induced pyroptosis were also observed with KN-93 treatment, and this was achieved without affecting TLR4 expression. Collectively, our work suggested that TAK-242 demonstrated substantial benefits against DCM both in vivo and in vitro, potentially attributed to the suppression of the TLR4-mediated CaMKII/NLRP3 pathway activity.

Development of a programmable automated cell culture system to study the lung pathophysiology of Cystic Fibrosis-related diabetes

The study of many diseases is limited by the in vitro systems available. Cystic Fibrosis-Related Diabetes (CFRD), the main co-morbidity of Cystic Fibrosis (CF), is a perfect example. Cells in vivo experience glucose fluctuations after meals. In contrast, cells cultured in vitro are initially exposed to high glucose media. Glucose gets progressively depleted until the next media change days later, which is not physiologically relevant and could negatively impact the results of research studies. To better study the mechanisms driving CFRD pathophysiology, we developed a programmable and automated cell culture system (PACCS) capable of mimicking acute hyperglycemic episodes experienced by CFRD patients after meals. We adapted a commercially available perfusion system and performed 3D modeling to develop this system. Results show that PACCS can be successfully used to culture airway epithelial cells, both immortalized and primary cells. Further, CF cells responded differently to meal-like conditioning when compared to controls, suggesting impaired adaptative responses in CF cells. Overall, PACCS will allow us to better study CFRD pathophysiology, and it could be used for a wide range of other applications.

Hyperglycemic environments directly compromise intestinal epithelial barrier function in an organoid model and hyaluronan (∼35 kDa) protects via a layilin dependent mechanism

BackgroundMetabolic syndrome and diabetes in obese individuals are strong risk factors for development of inflammatory bowel disease (IBD) and colorectal cancer. The pathogenic mechanisms of low-grade metabolic inflammation, including chronic hyperglycemic stress, in disrupting gut homeostasis are poorly understood. In this study, we sought to understand the impact of a hyperglycemic environment on intestinal barrier integrity and the protective effects of small molecular weight (35 kDa) hyaluronan on epithelial barrier function. MethodsIntestinal organoids derived from mouse colon were grown in normal glucose media (5 mM) or high glucose media (25 mM) to study the impact of hyperglycemic stress on the intestinal barrier. Additionally, organoids were pretreated with 35 kDa hyaluronan (HA35) to investigate the effect of hyaluronan on epithelial barrier under high glucose stress. Immunoblotting as well as confocal imaging was used to understand changes in barrier proteins, quantitative as well as spatial distribution, respectively. Alterations in barrier function were measured using trans-epithelial electrical resistance and fluorescein isothiocyanate flux assays. Untargeted proteomics analysis was performed to elucidate mechanisms by which HA35 exerts a protective effect on the barrier. Intestinal organoids derived from receptor knockout mice specific to various HA receptors were utilized to understand the role of HA receptors in barrier protection under high glucose conditions. ResultsWe found that high glucose stress decreased the protein expression as well as spatial distribution of two key barrier proteins, zona occludens-1 (ZO-1) and occludin. HA35 prevented the degradation or loss of ZO-1 and maintained the spatial distribution of both ZO-1 and occludin under hyperglycemic stress. Functionally, we also observed a protective effect of HA35 on the epithelial barrier under high glucose conditions. We found that HA receptor, layilin, was involved in preventing barrier protein loss (ZO-1) as well as maintaining spatial distribution of ZO-1 and occludin. Additionally, proteomics analysis showed that cell death and survival was the primary pathway upregulated in organoids treated with HA35 under high glucose stress. We found that XIAP associated factor 1 (Xaf1) was modulated by HA35 thereby regulating apoptotic cell death in the intestinal organoid system. Finally, we observed that spatial organization of both focal adhesion kinase (FAK) as well as F-actin was mediated by HA35 via layilin. ConclusionOur results highlight the impact of hyperglycemic stress on the intestinal barrier function. This is of clinical relevance, as impaired barrier function has been observed in individuals with metabolic syndrome. Additionally, we demonstrate barrier protective effects of HA35 through its receptor layilin and modulation of cellular apoptosis under high glucose stress.

Blocking TSP1 Ameliorates Diabetes Mellitus-Induced Erectile Dysfunction by Inhibiting the TGF-β/SMAD Pathway.

To examine the role and mechanism of thrombospondin-1 (TSP1) in the development of fibrosis in diabetes mellitus-induced erectile dysfunction (DMED). DMED was induced by intraperitoneal streptozotocin injection. All rats were categorized into three groups: control group (n=8), DMED group (n=8) and DMED+Leu-Ser-Lys-Leu (LSKL) group (n=8). After eight weeks following the induction of diabetes mellitus, the DMED+LSKL group was subjected to intraperitoneal injections of LSKL twice weekly for four weeks. To measure intracavernous pressure (ICP), a 25-gauge needle connected to a PE tube containing heparin was inserted into the corpus cavernosum (CC). Additionally, a needle was inserted into the carotid artery to measure mean arterial pressure (MAP). Sirius red staining and Masson trichrome staining were utilized to assess CC fibrosis. Moreover, high glucose (HG)-induced CC smooth muscle cells (CCSMCs) and CC fibroblasts (CCFs) were treated with or without LSKL. Western blotting and immunofluorescence were utilized to assess the phosphorylation and expression of related proteins. Compared with those in the control group, the ratio of the maximum ICP to the MAP markedly decreased in the DMED group, as did the ratio of smooth muscle to collagen and the ratio of collagen I to collagen III. These ratios were greater in the DMED+LSKL group than in the DMED group. TSP1 was highly expressed in the CC of DMED rats. In vitro experiments indicated that TSP1 expression significantly increased in the medium of CCSMCs and CCFs cultured in HG media and that the TGF-β pathway was activated in CCSMCs. Collagen IV was overexpressed in CCSMCs, indicating severe fibrosis was severe. Adding LSKL or knocking TSP1 down can prevent the activation of TGF-β signaling, as well as the overexpression of collagen IV in CCSMCs promoted by TSP1 secreted from CCSMCs itself or CCFs. TSP1 expression is increased in the CC of DMED rats. HG-induced TSP1 secretion via autocrine signaling from CCSMCs and/or paracrine signaling from CCFs to accelerate penile fibrosis. LSKL, an antagonist of TSP1, could improve erectile dysfunction by inhibiting the TGF-β/SMAD pathway.

Autophagy-enabled protein degradation: Key to platelet activation and ANGII production in patients with type 2 diabetes mellitus

BackgroundType 2 diabetes mellitus (T2DM) presents a thrombotic environment, contributing to diabetic macroangiopathy and microangiopathy. In this study, the regulation of microthrombosis in T2DM was assessed. MethodsPlatelets from T2DM patients and healthy controls were analyzed using 4D label-free proteomics and bioinformatics. The role of autophagy in T2DM platelet activation and conversion of platelet-derived angiotensinogen (AGT) was investigated. ResultsThe results showed that complement and coagulation cascades, platelet activation, metabolic pathways, endocytosis, autophagy, and other protein digestion-related pathways were enriched. The levels of the key protein AGT were increased in T2DM platelets. Chloroquine (CQ) inhibited ADP- or arachidonic acid (AA)-stimulated platelet aggregation and granule release in a dose-dependent manner, while the effects were less pronounced or even reversed for the proteasome inhibitor PYR-41 and the endocytosis inhibitor Pitstop 2. This indicated the dependence of platelet activation and the accompanying protein digestion on the autophagy-lysosome pathway. Mitophagy occurred in fresh T2DM platelets and ADP- or storage-stimulated platelets; mitophagy was inhibited by CQ. However, the mitophagy inhibitor Mdivi-1 failed to show effects similar to those of CQ. AGT, which could be transformed into ANGII in vitro by ADP-stimulated platelets, was upregulated in T2DM platelets and in MEG-01 cell-derived platelets cultured in a high-glucose medium. Finally, microthrombosis was alleviated as indicated by a reduction in the levels of red blood cells in the liver, spleen, heart, and kidney tissues of db/db mice treated with CQ or valsartan. ConclusionIn platelets, macroautophagy promotes protein digestion, subsequently facilitating platelet activation, ANGII-mediated vasoconstriction, and microthrombosis. Our results suggested that lysosome is a promising therapeutic target for antithrombotic treatment in T2DM.

The PAH1-encoded phosphatidate phosphatase of Yarrowia lipolytica differentially affects gene expression and lipid biosynthesis

Yarrowia lipolytica is a model oleaginous yeast with a strong capacity for lipid accumulation, yet its lipid metabolic pathways and regulatory mechanisms remain largely unexplored. The PAH1-encoded phosphatidate (PA) phosphatase governs lipid biosynthesis by its enzymatic activity and regulating the transcription of genes involved in phospholipid biosynthesis. In this work, we examined the effect of the loss of Pah1 (i.e., pah1Δ) on cell metabolism in cells growing in low- and high-glucose media. Multi-omics analyses revealed the global effect of the pah1Δ mutation on lipid and central carbon metabolism. Lipidomics analyses showed that the pah1Δ mutation caused a massive decrease in the masses of triacylglycerol (TAG) and diacylglycerol (DAG), and these effects were independent of glucose concentration in the media. Conversely, phospholipid levels declined in low-glucose media but increased in high-glucose media. The loss of Pah1 affected the expression of genes involved in key pathways of glucose metabolism, such as glycolysis, citric acid cycle, oxidative phosphorylation, and the pentose phosphate pathway, and these effects were more pronounced in high-glucose media. In lipid biosynthesis, the genes catalyzing phosphatidylcholine (PC) synthesis from phosphatidylethanolamine (PE) were upregulated within the CDP-DAG pathway. In contrast, PC synthesis through the Kennedy pathway was downregulated. The ethanolamine branch of the Kennedy pathway that synthesizes PE was also upregulated in pah1Δ. Interestingly, we noted a massive increase in the levels of lysophospholipids, consistent with the upregulation of genes involved in lipid turnover. Overall, this work identified novel regulatory roles of Pah1 in lipid biosynthesis and gene expression.

Targeting TXNIP in endothelial progenitors mitigates IL-8-induced neutrophil recruitment under metabolic stress

BackgroundThis study explores the potential role of Thioredoxin-interacting protein (TXNIP) silencing in endothelial colony-forming cells (ECFCs) within the scope of age-related comorbidities and impaired vascular repair. We aim to elucidate the effects of TXNIP silencing on vasculogenic properties, paracrine secretion, and neutrophil recruitment under conditions of metabolic stress.MethodsECFCs, isolated from human blood cord, were transfected with TXNIP siRNA and exposed to a high glucose and β-hydroxybutyrate (BHB) medium to simulate metabolic stress. We evaluated the effects of TXNIP silencing on ECFCs’ functional and secretory responses under these conditions. Assessments included analyses of gene and protein expression profiles, vasculogenic properties, cytokine secretion and neutrophil recruitment both in vitro and in vivo. The in vivo effects were examined using a murine model of hindlimb ischemia to observe the physiological relevance of TXNIP modulation under metabolic disorders.ResultsTXNIP silencing did not mitigate the adverse effects on cell recruitment, vasculogenic properties, or senescence induced by metabolic stress in ECFCs. However, it significantly reduced IL-8 secretion and consequent neutrophil recruitment under these conditions. In a mouse model of hindlimb ischemia, endothelial deletion of TXNIP reduced MIP-2 secretion and prevented increased neutrophil recruitment induced by age-related comorbidities.ConclusionsOur findings suggest that targeting TXNIP in ECFCs may alleviate ischemic complications exacerbated by metabolic stress, offering potential clinical benefits for patients suffering from age-related comorbidities.

Quercetin-4'-O-β-D-glucopyranoside inhibits podocyte injury by SIRT5-mediated desuccinylation of NEK7.

Diabetic kidney disease (DKD) is a complication of diabetic mellitus. New treatments need to be developed. This study aimed to investigate the effects of quercetin-4'-O-β-D-glucopyranoside (QODG) on podocyte injury. Podocytes were cultured in high glucose (HG) medium, treated with QODG, and overexpressing or knocking down SIRT5. Oxidative stress indicators were assessed using corresponding kits. Pyroptosis was detected by flow cytometry and western blot analysis. Succinylation modification was detected using immunoprecipitation (IP) and western blot analysis. The interaction between NEK7 and NLRP3 was determined by co-IP. The results indicated that QODG inhibited oxidative stress and pyroptosis of podocytes induced by HG. Besides, QODG suppressed succinylation levels in HG-induced podocytes, with the upregulation of SIRT5. Knockdown of SIRT5 reversed the effects of QODG on oxidative stress and pyroptosis. Moreover, SIRT5 inhibited the succinylation of NEK7 and the interaction between NLRP3 and NEK7. In conclusion, QODG upregulates SIRT5 to inhibit the succinylation modification of NEK7, impedes the interaction between NEK7 and NLRP3, and then inhibits the pyroptosis and oxidative stress injury of podocytes under HG conditions. The findings suggested that QODG has the potential to treat DKD and explore a novel underlying mechanism of QODG function.

Mesenchymal stem cells-derived exosomes alleviate senescence of retinal pigment epithelial cells by activating PI3K/AKT-Nrf2 signaling pathway in early diabetic retinopathy

Diabetic retinopathy (DR) is a major cause of vision loss and blindness in adults. Cellular senescence was involved in the pathogenesis of early-stage DR and is positively correlated with progression. Thus, our study aimed at exploring the effect and potential mechanism of Mesenchymal stem cells-derived exosomes (MSCs-EXOs) on Retinal Pigment Epithelial (RPE) cells senescence at an early stage of DR in vivo and in vitro. ARPE-19 cells were incubated in high glucose (HG) medium mixed with MSCs-EXOs to observe the changes in cell viability. Senescence-associated β-galactosidase (SA-β-gal) staining, Western blot and qRT-PCR were used to assess the expression of senescence-related genes and antioxidant mediators. Quantitative Real-Time polymerase chain reaction (qRT-PCR), Optical coherence tomography (OCT) Hematoxylin and eosin (HE) staining and Electroretinogram (ERG) were respectively used to verify cellular senescence, the structure and function of the retina. Our findings demonstrated that MSCs-EXOs inhibited HG-induced senescence in ARPE-19 cells. Furthermore, MSCs-EXOs reduced HG-induced cell apoptosis and oxidative stress levels while promoting cell proliferation. Mechanistically, HG suppressed PI3K/AKT phosphorylation as well as nuclear factor erythroid 2-related factor 2 (Nrf2) expression along with its downstream target gene expression in ARPE-19 cells. However, MSCs-EXOs reversed these changes by alleviating cellular senescence while enhancing antioxidant activity. In line with our results in vitro, MSCs-EXOs significantly ameliorated hyperglycemia-induced senescence in DR mice by downregulating mRNA expression of P53, P21, P16, and SASP. Additionally, MSCs-EXOs improved the functional and structural integrity of the retina in DR mice. Our study revealed the protective effect of MSCs-EXOs on cellular senescence, offering new insights for the treatment of DR.

The Anti-candidal and Absorbtion Performance of PVA/PVP-Based Jania rubens Hydrogel on Candida tropicalis and Some Physicochemical Properties of the Hydrogel.

This study was aimed to create a bioactive hydrogel form with PVA/PVP (polyvinyl alcohol/poly(N-vinylpyrrolidone) polymer using acetone and ethanol extractions of Jania rubens red algae and investigate some pharmaceutical properties. The anti-candidal activity and some inhibition performance of J. rubens/PVA/PVP hydrogel were investigated on Candida tropicalis which is one of the important causes of bloodstream infections. The physicochemical properties of J. rubens/PVA/PVP hydrogel were revealed using FTIR and swelling-absorption tests. The volatile compounds of J. rubens extracts were examined by GCMS. By mixing the extracts in equal proportions, PVA/PVP-based hydrogel was prepared. According to the results, Cumulative Drug Release was stable at 25°C for the first 5h. The IZ (inhibition zone) and MIC (minimum inhibitory concentration) of J. rubens/PVA/PVP hydrogel were 9.01mm and 80.20mg/mL, respectively. It was found that logarithmic reduction and percent reduction were seen as 1.5CFU/mL and 97.5%, respectively, on C. tropicalis exposed to J. rubens/PVA/PVP hydrogel in the first 5min of the incubation. After exposure of C. tropicalis to J. rubens/PVA/PVP, the number of viable cells transferred from the gel to water was between 76.1 and 73.1% in high glucose medium, while it was between 92.2 and 80.8% for the PVA/PVP hydrogel under the same conditions. As a result, PVA/PVP hydrogel was made bioactive with J. rubens extracts for the first time in this study, and its potential for use as a functional anticandidal hydrogel on C. tropicalis has been demonstrated.

Liraglutide reduces bone marrow adipogenesis by miR-150-5p/ GDF11 axis in diabetic rats

In recent years, a common-used antidiabetic drug, liraglutide, was identified with extra effects on lipid metabolism. Its effects against excessive lipid deposition in bone marrow were gained much attention but not well established. Our aim in the present study is to explore the interaction of miRNAs-mRNAs altered by liraglutide administration during bone marrow adipogenesis in diabetes. To establish the diabetic animal model, rats were treated with high fat diet (HFD) and STZ injection. We then identified the lowering effect of liraglutide on lipids metabolism in the diabetes. During this process, high-throughput sequencing and bioinformatics analyses on miRNAs extracted from bone marrow mesenchymal stem cells (BMSCs) were conducted after liraglutide administration. We then identified five differentially expressed miRNAs (miRNA-150-5p, miRNA-129-5p, miRNA-201-3p, miRNA-201-5p, and miRNA-214-5p). The expressions of the DE miRNAs were verified as temporal specific expression patterns in Day 3 and in Day 7. Among them, miRNA-150-5p expression was more stable and consistent with the sequencing data. Of interest, miR-150-5p overexpression facilitated adipogenesis of BMSCs. But this promotion was alleviated by liraglutide. The predicted target gene of miR-150-5p, GDF11, was validated to be involved in liraglutide alleviated BMSCs’ lipid accumulation in diabetes. In vitro, liraglutide increased the GDF11 expression, rescued its down-expression by siGDF11 and inhibit the adipogenesis of BMSCs cultured in high glucose medium. In vivo, liraglutide reversed the HFD-STZ induced excessive lipid droplets by up-regulation of GDF11 expression, which was discounted by agomiR-150-5p injection. Above all, liraglutide might alleviate bone marrow fat accumulation via inactivating miR-150-5p/GDF11 axis in diabetes.

TRNA-derived RNA fragment, tRF-18-8R6546D2, promotes pancreatic adenocarcinoma progression by directly targeting ASCL2

Pancreatic adenocarcinoma (PAAD) is a life-threatening cancer. Exploring new diagnosis and treatment targets helps improve its prognosis. tRNA-derived small non-coding RNAs (tsRNAs) are a novel type of gene expression regulators and their dysregulation is closely related to many human cancers. Yet the expression and functions of tsRNAs in PAAD are not well understood. Our study used RNA sequencing to identify tsRNA expression profiles in PAAD cells cultured in no or high glucose media and found tRF-18-8R6546D2 was an uncharacterized tsRNA, which has significantly high expression in PAAD cells and tissues. Clinically, tRF-18-8R6546D2 is linked to poor prognosis in PAAD patients and can be used to distinguish them from healthy populations. Functionally, in vitro and vivo, tRF-18-8R6546D2 over-expression promoted PAAD cell proliferation, migration and invasion, inhibited apoptosis, whereas tRF-18-8R6546D2 knock-down showed opposite effects. Mechanistically, tRF-18-8R6546D2 promoted PAAD malignancy partly by directly silencing ASCL2 and further regulating its downstream genes such as MYC and CASP3. These findings show that tRF-18-8R6546D2 is a novel oncogenic factor and can be a promising diagnostic or prognostic biomarker and therapeutic target for PAAD.

Nicotinate-curcumin improves NASH by inhibiting the AKR1B10/ACCα-mediated triglyceride synthesis

BackgroundNonalcoholic steatohepatitis (NASH) is a prevalent chronic liver condition. However, the potential therapeutic benefits and underlying mechanism of nicotinate-curcumin (NC) in the treatment of NASH remain uncertain.MethodsA rat model of NASH induced by a high-fat and high-fructose diet was treated with nicotinate-curcumin (NC, 20, 40 mg·kg− 1), curcumin (Cur, 40 mg·kg− 1) and metformin (Met, 50 mg·kg− 1) for a duration of 4 weeks. The interaction between NASH, Cur and Aldo-Keto reductase family 1 member B10 (AKR1B10) was filter and analyzed using network pharmacology. The interaction of Cur, NC and AKR1B10 was analyzed using molecular docking techniques, and the binding energy of Cur and NC with AKR1B10 was compared. HepG2 cells were induced by Ox-LDL (25 µg·ml− 1, 24 h) in high glucose medium. NC (20µM, 40µM), Cur (40µM) Met (150µM) and epalrestat (Epa, 75µM) were administered individually. The activities of ALT, AST, ALP and the levels of LDL, HDL, TG, TC and FFA in serum were quantified using a chemiluminescence assay. Based on the changes in the above indicators, score according to NAS standards. The activities of Acetyl-CoA and Malonyl-CoA were measured using an ELISA assay. And the expression and cellular localization of AKR1B10 and Acetyl-CoA carboxylase (ACCα) in HepG2 cells were detected by Western blotting and immunofluorescence.ResultsThe results of the animal experiments demonstrated that NASH rat model induced by a high-fat and high-fructose diet exhibited pronounced dysfunction in liver function and lipid metabolism. Additionally, there was a significant increase in serum levels of FFA and TG, as well as elevated expression of AKR1B10 and ACCα, and heightened activity of Acetyl-CoA and Malonyl-CoA in liver tissue. The administration of NC showed to enhance liver function in rats with NASH, leading to reductions in ALT, AST and ALP levels, and decrease in blood lipid and significant inhibition of FFA and TG synthesis in the liver. Network pharmacological analysis identified AKR1B10 and ACCα as potential targets for NASH treatment. Molecular docking studies revealed that both Cur and NC are capable of binding to AKR1B10, with NC exhibiting a stronger binding energy to AKR1B10. Western blot analysis demonstrated an upregulation in the expression of AKR1B10 and ACCα in the liver tissue of NASH rats, accompanied by elevated Acetyl-CoA and Malonyl-CoA activity, and increased levels of FFA and TG. The results of the HepG2 cell experiments induced by Ox-LDL suggest that NC significantly inhibited the expression and co-localization of AKR1B10 and ACCα, while also reduced levels of TC and LDL-C and increased level of HDL-C. These effects are accompanied by a decrease in the activities of ACCα and Malonyl-CoA, and levels of FFA and TG. Furthermore, the impact of NC appears to be more pronounced compared to Cur.ConclusionNC could effectively treat NASH and improve liver function and lipid metabolism disorder. The mechanism of NC is related to the inhibition of AKR1B10/ACCα pathway and FFA/TG synthesis of liver.

Upregulation of rate-limiting enzymes in cholesterol metabolism by PKCδ mediates endothelial apoptosis in diabetic wound healing

Diabetic foot ulcer (DFU) is a prevalent complication of diabetes that poses significant challenges in terms of treatment and management. It is characterized by heightened endothelial apoptosis and impaired angiogenesis. In this study, we aimed to investigate the role of protein kinase Cδ (PKCδ) in regulating endothelial apoptosis in diabetic wounds by promoting cholesterol biosynthesis. The expression of PKCδ was increased in human umbilical vascular endothelial cells (HUVECs) cultivated in high glucose medium and skin tissue isolated from diabetic mice. High glucose-induced HUVECs apoptosis was reduced by PKCδ inhibition with siRNA or rottlerin. RNA-seq identified two enzymes, 3-hydroxy-3-methylglutaryl-CoA synthase 1 (HMGCS1) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), as the downstream of PKCδ. PKCδ knockdown or inhibition suppressed the expression of HMGCS1 and HMGCR and lowered free cholesterol (FC) levels. Cholesterol restored high glucose-induced apoptosis in siRNA- or rottlerin-treated HUVECs. In vivo use of rosuvastatin calcium, an inhibitor of HMGCR, downregulated free cholesterol levels and accelerated the wound healing process. In conclusion, PKCδ expression in endothelial cells was activated by high glucose, which subsequently upregulates the expression of two enzymes catalyzing cholesterol biosynthesis, HMGCS1 and HMGCR. Enhanced cholesterol biosynthesis raises free cholesterol levels, promotes endothelial apoptosis, and finally delays wound healing.

Effects of asiaticoside on the model of gestational diabetes mellitus in HTR-8/svneo cells via PI3K/AKT pathway

Background Asiaticoside (AS) has been reported to improve the changes induced by high glucose stimulation, and it may have potential therapeutic effects on gestational diabetes mellitus (GDM). This study aims to explore the effect of AS on the cell model of GDM and the action mechanism of the PI3K/AKT pathway. Methods The GDM model was established in HTR-8/Svneo cells with a high glucose (HG) medium. After the cytotoxicity assay of AS, cells were divided into the control group, HG group and HG + AS group to conduct control experiment in cells. The cell proliferation and migration were detected by CCK-8 assay and scratch test, respectively. The mRNA levels of PI3K, AKT2, mTORC1, and GLUT4 in PI3K/AKT signalling pathway were measured by RT-PCR, and the protein expressions of these signalling molecules were monitored by western blot. Results AS showed a promotion effect on the cell proliferation rate of HTR-8/Svneo cells, and 80 μmol/L AS with a treatment time of 48 h had no cytotoxicity. The cell proliferation rate, migration rate, mRNA levels and protein expressions of PI3K, AKT2, mTORC1, and GLUT4 in the HG group were significantly lower than those in the control group, which were significantly increased in the HG + AS group (p < 0.05). Conclusions AS can facilitate the cell proliferation and migration in the cell model of GDM, and might play a role in GDM treatment via PI3K/AKT pathway.