Panax notoginseng saponins alleviate skeletal muscle insulin resistance by regulating the IRS1-PI3K-AKT signaling pathway and GLUT4 expression

Panax Notoginseng Saponins Regulate Angiogenic Cytokines Through the PI3K/AKT/mTOR Signaling Pathway to Promote Fracture Healing in Ovariectomized Rats

Osteoporotic fractures seriously affect the quality of life of the elderly. Panax notoginseng saponins (PNS) have the potential function of preventing osteoporosis. The Phosphatidylinositol 3-kinase (PI3K)/protein kinase (AKT)/mammalian target of rapamycin (mTOR) pathway is involved in the regulation of osteoporosis and has been proven to be related to VEGF secretion and angiogenesis. Therefore, this study aimed to explore the effects of PNS on ovariectomized rats with osteoporotic fracture through the PI3K/AKT/mTOR pathway and angiogenesis-related factors. Female Sprague-Dawley rats were randomly divided into normal control, fracture model, ovariectomized fracture model, low-dose PNS (100 mg/kg/d), and high-dose PNS (200 mg/kg/d). The ovariectomized rat fracture model was established. In low and high dose groups, PNS was administered intraperitoneally. The vascularization of fracture ends was detected in vitro by micro-CT on the 7th, 14th, and 21st day after modeling, and the area and number of blood vessels in the unit field of vision of the callus healing plane were seen by hematoxylin-eosin staining. The expression levels of PI3K, AKT1, mTOR, hypoxia inducible factor-1; VEGF: vascular endothelial growth factor (HIF-1), VEGF, Ang-1, VEGFR2, and angiopoietin like 2 Gene (ANGPTL2) were determined using Western blotting. In the PNS treatment group, the area of cortical bone increased, the area of callus decreased, and the number and area of blood vessels increased significantly when compared with the ovariectomized fracture model group. PNS regulates the PI3K/AKT/mTOR signaling pathway and promotes the expression of vascular-related cytokines (VEGF, Ang-1, VEGFR2, and ANGPTL2) in osteoporotic fractures. PNS may regulate the expression of vascular-related factors through the PI3K/AKT/mTOR pathway and promote the healing of osteoporotic fractures in ovariectomized rats.

Developments in the study of Chinese herbal medicine's assessment index and action mechanism for diabetes mellitus

In traditional Chinese medicine (TCM), based on various pathogenic symptoms and the 'golden chamber' medical text, Huangdi Neijing, diabetes mellitus falls under the category 'collateral disease'. TCM, with its wealth of experience, has been treating diabetes for over two millennia. Different antidiabetic Chinese herbal medicines reduce blood sugar, with their effective ingredients exerting unique advantages. As well as a glucose lowering effect, TCM also regulates bodily functions to prevent diabetes associated complications, with reduced side effects compared to western synthetic drugs. Chinese herbal medicine is usually composed of polysaccharides, saponins, alkaloids, flavonoids, and terpenoids. These active ingredients reduce blood sugar via various mechanism of actions that include boosting endogenous insulin secretion, enhancing insulin sensitivity and adjusting key enzyme activity and scavenging free radicals. These actions regulate glycolipid metabolism in the body, eventually achieving the goal of normalizing blood glucose. Using different animal models, a number of molecular markers are available for the detection of diabetes induction and the molecular pathology of the disease is becoming clearer. Nonetheless, there is a dearth of scientific data about the pharmacology, dose-effect relationship, and structure-activity relationship of TCM and its constituents. Further research into the efficacy, toxicity and mode of action of TCM, using different metabolic and molecular markers, is key to developing novel TCM antidiabetic formulations.

Berberine attenuates obesity-induced insulin resistance by inhibiting miR-27a secretion

INTRODUCTION

Berberine (BBR) is an alkaloid found in plants. It has neuroprotective, anti-inflammatory and lipid-lowering activity. However, the efficacy of treatment with BBR and the mechanisms through which it acts need further study.

AIMS

This study investigated the therapeutic effects and the mechanism of action of BBR on obesity-induced insulin resistance in peripheral tissues.

METHODS

High-fat-fed C57BL/6J mice and low-fat-fed C57BL/6J mice with miR-27a overexpression were given BBR intervention (100 mg/kg, po), and the oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were performed. Palmitic acid-stimulated hypertrophic adipocyte models were treated with BBR (10 μM). Related indicators and protein expression levels were examined.

RESULTS

The AUCs of the OGTT and the ITT in the BBR intervention group were reduced significantly (p < 0.01) (p < 0.05), and the serum biochemical parameters, including FBG, TC, TG and LDL-C were significantly reduced after BBR intervention. In the in vitro experiments, the triglyceride level and volume of lipid droplets decreased significantly after BBR intervention (p < 0.01) (p < 0.05). Likewise, BBR ameliorates skeletal muscle and pancreas insulin signalling pathways in vivo and in vitro.

DISCUSSION

The results showed that BBR significantly ameliorated insulin resistance, reduced body weight and percent body fat and improved serum biochemical parameters in mice. Likewise, BBR reduced triglyceride level and lipid droplet volume in hypertrophic adipocytes, BBR improved obesity effectively. Meanwhile, BBR ameliorated the histomorphology of the pancreas, and skeletal muscle and pancreas insulin related signalling pathways of islets in in vitro and in vivo experiments. The results further demonstrated that BBR inhibited miR-27a levels in serum from obese mice and supernatant of hypertrophic adipocytes. miR-27a overexpression in low-fat fed mice indicated that miR-27a caused insulin resistance, and BBR intervention significantly improved the miR-27a induced insulin resistance status.

CONCLUSION

This study demonstrates the important role of BBR in obesity-induced peripheral insulin resistance and suggest that the mechanism of its effect may be inhibition of miR-27a secretion.

Eicosapentaenoic Acid Alleviates Inflammatory Response and Insulin Resistance in Pregnant Mice With Gestational Diabetes Mellitus

This study investigated the effect of eicosapentaenoic acid (EPA) on insulin resistance in pregnant mice with gestational diabetes mellitus (GDM) and underlying mechanism. C57BL/6 mice fed with a high-fat diet for 4 weeks and the newly gestated were selected and injected with streptozotocin for GDM modeling. We demonstrated that the fasting insulin levels (FINS) and insulin sensitivity index (ISI) in serum and blood glucose level were significantly higher in GDM group than in normal control (NC) group. The low or high dose of EPA intervention reduced these levels, and the effect of high dose intervention was more significant. The area under the curve in GDM group was higher than that of NC group, and then gradually decreased after low or high dose of EPA treatment. The serum levels of TC, TG and LDL were increased in GDM group, while decreased in EPA group. GDM induced down-regulation of HDL level, and the low or high dose of EPA gradually increased this level. The levels of p-AKT2Ser, p-IRS-1Tyr, GLUT4, and ratios of pIRS-1Tyr/IRS-1 and pAKT2Ser/AKT2 in gastrocnemius muscle were reduced in GDM group, while low or high dose of EPA progressively increased these alterations. GDM enhanced TLR4, NF-kappaB p65, IL-1beta, IL-6 and TNF-alpha levels in placental tissues, and these expressions were declined at different dose of EPA, and the decrease was greater at high dose. We concluded that EPA receded the release of inflammatory factors in the placental tissues by inhibiting the activation of TLR4 signaling, thereby alleviating the IR.

Molecular mechanism of Gan-song Yin inhibiting the proliferation of renal tubular epithelial cells by regulating miR-21-5p in adipocyte exosomes

ETHNOPHARMACOLOGICAL RELEVANCE

Gan-song Yin is derived from the classic ancient prescription " Gan-song pill " for the treatment of wasting-thirst in Ningxia combined with the characteristic "fragrant medicine". It is clinically used for the treatment of early renal fibrosis caused by diabetic nephropathy. Previous studies have shown that it has a good effect and great potential in the prevention and treatment of diabetic nephropathy, but its mechanism research is still limited.

AIM OF THE STUDY

To investigate the mechanism of GSY to improve DN by interfering with miR-21-5p and glycolipid metabolism in adipocyte exosomes using 3T3-L1 and TCMK-1 co-culture system.

MATERIALS AND METHODS

The co-culture system of 3T3-L3 and TCMK-1 was established, the IR model was established, and the stability, lipid drop change, glucose consumption, triglyceride content, cell viability, cell cycle and apoptosis level, protein content and mRNA expression of the IR model were detected.

RESULTS

GSY inhibited 3T3-L1 activity, increased glucose consumption and decreased TG content. Decreased TCMK-1 cell viability, inhibited apoptosis, cell cycle arrest occurred in G0/G1 phase and S phase. Adipocyte IR model and co-culture system were stable within 48 h. After GSY intervention, lipid droplet decomposition and glucose consumption increased. The TG content of adipocytes increased, while the TG content of co-culture system decreased. GSY can regulate the expression of TGF-β1/SMAD signaling pathway protein in IR state. After GSY intervention, the expression of miR-21-5p was increased in 3T3-L1 and Exo cells, and decreased in TCMK-1 cells.

CONCLUSIONS

GSY can regulate TGF-β1/SMAD signaling pathway through the secretion of miR-21-5p from adipocytes, protect IR TCMK-1, regulate the protein and mRNA expression levels of PPARγ, GLUT4, FABP4, and improve glucose and lipid metabolism.

Panax notoginseng saponins inhibits oxidative stress- induced human nucleus pulposus cell apoptosis and delays disc degeneration in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Panax notoginseng (Burk) F. H. Chen has been a popular traditional Chinese medicine with a long history of treating low back pain. Its main active ingredient, Panax notoginseng saponins (PNS), can be found in several Chinese patent medicines that are frequently used to treat blood stasis type low back pain. Intervertebral disc degeneration (IDD) is the most common cause of back pain, and the injection of PNS has been used to relieve IDD-induced back pain in clinical practice. Despite its effectiveness, the exact mechanisms of action for PNS injections remain unclear.

AIM OF THE STUDY

IDD as a consequence of aging involves apoptosis of nucleus pulposus (NP) cells and imbalanced degradation of extracellular matrix (ECM) induced by several factors including oxidative stress. We hypothesized that PNS may have a therapeutic effect on IDD via inhibiting apoptosis of NP cells and degradation of ECM under oxidative stress.

MATERIALS AND METHODS

In this study, network pharmacology was initially employed to predict the targets of PNS against IDD. Subsequently, commercial PNS was analyzed by high-performance liquid chromatography to confirm the ingredients for in vitro and in vivo experiments. In vitro experiments were conducted on human nucleus pulposus (HNP) cells, including CCK-8, RT-PCR, Western blot, immunofluorescence staining, autophagic flux detection, and TUNEL assay. In vivo experiments were also performed on rats with IDD of tail discs induced by annular fibrosus needle puncture, which involved MRI, HE staining, and immunohistochemistry.

RESULTS

Our study demonstrated the theoretical targets of PNS against IDD, including Caspase 3, MMP13, Akt, and autophagy, based on network pharmacology. Subsequently, in vitro experiments revealed that PNS attenuated cellular apoptosis of NP by suppressing the expression of cleaved-caspase 3 and the ratio of Bax/Bcl-2 under H2O2 stimulation. Autophagy was also inhibited by PNS treatment, and the protective effect was abolished with rapamycin, an autophagy inducer, indicating that autophagy inhibition was involved in the protective effect of PNS on IDD. Furthermore, Akt/mTOR pathway activation was observed in HNP cells responding to H2O2 with PNS treatment, which played a role in autophagy downregulation. PNS was also shown to promote the expression of anabolic genes such as COL2A1 and ACAN while inhibiting the expression of catabolic gene MMP13 in HNP cells. In addition, the in vivo study revealed that PNS treatment could ameliorate IDD in a puncture-induced rat tail model. The development of IDD was significantly reduced, and there was decreased MMP13 expression, as well as increased COL2A1 protein expression in NP tissues.

CONCLUSION

Our study showed that PNS could protect HNP cells against apoptosis via autophagy inhibition and ameliorate disc degeneration in vivo, indicating its potential to be a therapeutic agent for IDD.

Notoginsenoside-R1 ameliorates palmitic acid-induced insulin resistance and oxidative stress in HUVEC via Nrf2/ARE pathway

Panax notoginseng, a Chinese traditional food and herb medicine, possesses notable cardiovascular health-promoting properties, with notoginsenoside (NG)-R1 being a key active compound. Insulin resistance represents a global health concern associated with various metabolic disorders. This study investigated the effects of NG-R1 on palmitic acid (PA)-induced insulin resistance and oxidative stress in human umbilical vein endothelial cells (HUVECs). Our findings demonstrate that NG-R1 significantly alleviated impaired glucose uptake, enhanced the phosphorylation of protein kinase B (PKB/Akt) at Ser473, and reduced the phosphorylation of insulin receptor substrate 1 (IRS-1) at Ser307 in PA-treated HUVECs. Furthermore, NG-R1 treatment significantly lowered the levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), while increasing the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). Additionally, NG-R1 activated the Nrf2/ARE signaling pathway, leading to a substantial increase in the expression of antioxidant enzymes. Notably, knockdown of Nrf2 attenuated the beneficial effects of NG-R1 on PA-induced insulin resistance and oxidative stress in HUVECs, suggesting that NG-R1 exerts its effects through the Nrf2/ARE pathway. In summary, our study reveals that NG-R1 ameliorated PA-induced insulin resistance in HUVECs via Nrf2/ARE pathway, providing novel insights into its potential for alleviating metabolic disorders and cardiovascular disease.

Panax notoginseng saponins reverse steroid resistance in lupus nephritis: Involvement of the suppression of exosomal P-gp levels from lymphocytes to glomerular endothelial cells

Microangiopathy is the most basic pathological manifestation of lupus nephritis (LN), and glomerular endothelial cells (GECs) injury is an important pathological mechanism. LN patients with microangiopathy are prone to steroid resistance (SR). Our previous studies confirmed that Panax notoginseng saponins (PNS) could reverse SR by downregulating the expression of P-gp in SR lymphocytes of LN mice (SLCsL/S). However, the mechanism of how circulating lymphocytes transmit SR information to GECs and thus affect the efficacy of kidney treatment is not clear. Recent studies have found that exosomes (exos) are an important carrier for intercellular bioactive substance communication. But whether exosomes derived from SLCsL/S mediate SR in GECs and PNS interventions. To solve this problem, Exosomes isolated from SLCsL/S were characterized, and in vitro cell coculture was further conducted to investigate the effect of SLCsL/S-derived exosomes in the SR of GECs and PNS intervention. Sequencing was used to define the exosomal miRNA expression profiling of SR GECs. Moreover, the in vivo experiments were performed through the injection of exosomes extracted from SLCsL/S into the tail vein of mice. Our research results indicate that exosomes derived from SLCsL/S could transmit SR information to GECs and lead to the aggravation of inflammatory injury through conferring P-gp, which were negated by a P-gp inhibitor. Further, we identified higher levels of exosomal miR-125b-5p from SR GECs were associated with SR in LN and could serve as biomarker for the risk of developing SR. PNS could reverse the SR of GECs and alleviate inflammatory injury by suppressing exosomal P-gp levels from lymphocytes to GECs in vitro and in vivo. However, the specific molecular mechanism by which PNS regulates exosomes has not yet been elucidated, and we need to conduct more in-depth research in the future. Overall, Our findings suggest that exosomal transfer of SLCsL/S derived P-gp confer SR to GECs, and PNS can target exosome communication to reverse SR in LN, which provides new ideas and a scientific basis for improving the clinical efficacy of traditional Chinese medicine in the treatment of refractory LN.

Wild Rosa roxburghii Tratt Juices Grown at Different Altitudes Regulate Blood Glucose in Type 1 Diabetic Mice via the PI3K/Akt Pathway

To explore hypoglycemic effect of wild Rosa roxburghii tratt (RRT) juice at different altitudes on type 1 diabetes mellitus (T1DM). The T1DM mouse model was induced by streptozotocin (STZ), and the experiment included a normal group (NC), model group (MC), wild RRT juice groups high (HF), medium (MF), low altitude (DF) and cultivated control group (PC). During experiment, food intake, water intake, body weight, and fasting blood glucose were measured. After 28 days of administration, glucose tolerance, glycogen level, lipid profiles, and antioxidation levels in serum and liver were measured, and histomorphological changes of liver and kidney were observed by hematoxylin and eosin staining. The results showed that wild RRT juice reduced blood glucose level, alleviated liver and kidney tissue damage, improved glucose and lipid metabolism disorders and attenuated oxidative damage in T1DM mice. Western blot showed that wild RRT juice at grown at different altitudes significantly increased protein abundance of PI3K, Akt, and GLUT2 in liver of T1DM mice. In conclusion, wild RRT juice from different altitudes improved glucose and lipid metabolism disorders and oxidative damage in T1DM mice, which may be attributed to activation of PI3K/Akt pathway. Overall effect: MF > PC > HF > DF.

Identification of Potential Mechanisms of Rk1 Combination with Rg5 in the Treatment of Type II Diabetes Mellitus by Integrating Network Pharmacology and Experimental Validation

In this study, we aimed to explore the potential targets and functional mechanisms of Rk1 combined with Rg5 (Rk1+Rg5) against type II diabetes mellitus (T2DM). Network pharmacology and molecular docking were used to predict and verify the targets and signaling pathways of Rk1+Rg5 against T2DM. The results were further confirmed by a db/db mouse model and a model using PA-induced L6 cells. According to network pharmacology, a total of 250 core targets of Rk1+Rg5 towards T2DM were identified; the insulin resistance signaling pathways were enriched by KEGG. Results of molecular docking indicated good binding affinity of Rk1 and Rg5 to Akt1. In vivo and in vitro studies further showed that Rk1+Rg5 is an inhibitor of skeletal muscle insulin resistance. The results showed that Rk1+Rg5 significantly improved the hyperglycemic state of db/db mice, alleviated dyslipidemia, and promoted skeletal muscle glucose uptake. This phenomenon was closely related to the alleviation of the insulin resistance in skeletal muscles. Finally, the combination activated the Akt signaling pathway and promoted GLUT4 translocation to the cell membrane for glucose uptake. Altogether, our findings, for the first time, demonstrate that the combination of Rk1 and Rg5 could be beneficial for anti-T2DM, possibly involving ameliorated insulin resistance.

The Role of SOCS3 in Regulating Meat Quality in Jinhua Pigs

Meat quality is an important economic trait that influences the development of the pig industry. Skeletal muscle development and glycolytic potential (GP) are two crucial aspects that significantly impact meat quality. It has been reported that abnormal skeletal muscle development and high glycogen content results in low meat quality. However, the genetic mechanisms underlying these factors are still unclear. Compared with intensive pig breeds, Chinese indigenous pig breeds, such as the Jinhua pig, express superior meat quality characteristics. The differences in the meat quality traits between Jinhua and intensive pig breeds make them suitable for uncovering the genetic mechanisms that regulate meat quality traits. In this study, the Jinhua pig breed and five intensive pig breeds, including Duroc, Landrace, Yorkshire, Berkshire, and Pietrain pig breeds, were selected as experimental materials. First, the F_ST and XP-EHH methods were used to screen the selective signatures on the genome in the Jinhua population. Then, combined with RNA-Seq data, the study further confirmed that SOCS3 could be a key candidate gene that influences meat quality by mediating myoblast proliferation and glycometabolism because of the down-regulated expression of SOCS3 in Jinhua pigs compared with Landrace pigs. Finally, through SOCS3 knockout (KO) and overexpression (OE) experiments in mouse C2C12 cells, the results showed that SOCS3 regulated the cell proliferation of myoblasts. Moreover, SOCS3 is involved in regulating glucose uptake by the IRS1/PI3K/AKT signaling pathway. Overall, these findings provide a basis for the genetic improvement of meat quality traits in the pig industry.

Panax notoginseng alleviates oxidative stress through miRNA regulations based on systems biology approach

BACKGROUND

Herbal medicine Sanqi (SQ), the dried root or stem of Panax notoginseng (PNS), has been reported to have anti-diabetic and anti-obesity effects and is usually administered as a decoction for Chinese medicine. Alternative to utilizing PNS pure compound for treatment, we are motivated to propose an unconventional scheme to investigate the functions of PNS mixture. However, studies providing a detailed overview of the transcriptomics-based signaling network in response to PNS are seldom available.

METHODS

To explore the reasoning of PNS in treating metabolic disorders such as insulin resistance, we implemented a systems biology-based approach with RNA sequencing (RNA-seq) and miRNA sequencing data to elucidate key pathways, genes and miRNAs involved.

RESULTS

Functional enrichment analysis revealed PNS up-regulating oxidative stress-related pathways and down-regulating insulin and fatty acid metabolism. Superoxide dismutase 1 (SOD1), peroxiredoxin 1 (PRDX1), heme oxygenase-1 (Hmox1) and glutamate cysteine ligase (GCLc) mRNA and protein levels, as well as related miRNA levels, were measured in PNS treated rat pancreatic β cells (INS-1). PNS treatment up-regulated Hmox1, SOD1 and GCLc expression while down-regulating miR-24-3p and miR-139-5p to suppress oxidative stress. Furthermore, we verified the novel interactions between miR-139-5p and miR-24-3p with GCLc and SOD1.

CONCLUSION

This work has demonstrated the mechanism of how PNS regulates cellular molecules in metabolic disorders. Therefore, combining omics data with a systems biology strategy could be a practical means to explore the potential function and molecular mechanisms of Chinese herbal medicine in the treatment of metabolic disorders.

Molecular and biochemical investigations of the anti-fatigue effects of tea polyphenols and fruit extracts of Lycium ruthenicum Murr. on mice with exercise-induced fatigue

Background: The molecular mechanisms regulating the therapeutic effects of plant-based ingredients on the exercise-induced fatigue (EIF) remain unclear. The therapeutic effects of both tea polyphenols (TP) and fruit extracts of Lycium ruthenicum (LR) on mouse model of EIF were investigated. Methods: The variations in the fatigue-related biochemical factors, i.e., lactate dehydrogenase (LDH), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-2 (IL-2), and interleukin-6 (IL-6), in mouse models of EIF treated with TP and LR were determined. The microRNAs involved in the therapeutic effects of TP and LR on the treatment of mice with EIF were identified using the next-generation sequencing technology. Results: Our results revealed that both TP and LR showed evident anti-inflammatory effect and reduced oxidative stress. In comparison with the control groups, the contents of LDH, TNF-α, IL-6, IL-1β, and IL-2 were significantly decreased and the contents of SOD were significantly increased in the experimental groups treated with either TP or LR. A total of 23 microRNAs (21 upregulated and 2 downregulated) identified for the first time by the high-throughput RNA sequencing were involved in the molecular response to EIF in mice treated with TP and LR. The regulatory functions of these microRNAs in the pathogenesis of EIF in mice were further explored based on Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses with a total of over 20,000-30,000 target genes annotated and 44 metabolic pathways enriched in the experimental groups based on GO and KEGG databases, respectively. Conclusion: Our study revealed the therapeutic effects of TP and LR and identified the microRNAs involved in the molecular mechanisms regulating the EIF in mice, providing strong experimental evidence to support further agricultural development of LR as well as the investigations and applications of TP and LR in the treatment of EIF in humans, including the professional athletes.

Skeletal Muscle CSE Deficiency Leads to Insulin Resistance in Mice

Cystathionine-γ-lyase (CSE) is expressed in various tissues and generates H₂S via an alternative desulfuration reaction. We sought to explore the functions of skeletal muscle CSE using skeletal muscle conditional knockout CSE (MCSEKO) mice. It was found that body weight, muscle morphology, and exercise capacity were not altered in MCSEKO mice compared with littermate wild-type mice. RNA-seq-based transcriptome analysis showed that 275 genes were differentially regulated in skeletal muscle and multiple signaling pathways including insulin signaling and mTOR, PI3K-AKT, and cGMP-PKG signaling pathways were enriched in MCSEKO mice. The intraperitoneal glucose tolerance test and insulin tolerance test showed that glucose tolerance and insulin sensitivity were reduced in MCSEKO mice. Glucose transporter 4 (GLU4) and PKG-1 expression levels and insulin receptor substrate-1(IRS1)/PI3K/Akt signaling pathway were downregulated whilst the mTOR/S6K/S6 pathway was enhanced in MCSEKO mice. These effects were reversed by the H₂S supplement. Aerobic treadmill training significantly promoted glucose tolerance and insulin sensitivity and improved GLU4 and PKG-1 levels, promoted IRS1/PI3K/Akt signaling and suppressed mTOR/S6K/S6 signaling pathway in MCSEKO mice. Our data suggest that skeletal muscle CSE/H₂S signaling is critical for the maintenance of insulin sensitivity, which is associated with maintaining the balance in PKG, PI3K/Akt, and mTOR/S6K/S6 signaling pathways in skeletal muscle.

Andrographolide Promotes Uptake of Glucose and GLUT4 Transport through the PKC Pathway in L6 Cells

Glucose transporter 4 (GLUT4) is a membrane protein that regulates blood glucose balance and is closely related to type 2 diabetes. Andrographolide (AND) is a diterpene lactone extracted from herbal medicine Andrographis paniculata, which has a variety of biological activities. In this study, the antidiabetic effect of AND in L6 cells and its mechanism were investigated. The uptake of glucose of L6 cells was detected by a glucose assay kit. The expression of GLUT4 and phosphorylation of protein kinase B (PKB/Akt), AMP-dependent protein kinase (AMPK), and protein kinase C (PKC) were detected by Western blot. At the same time, the intracellular Ca2+ levels and GLUT4 translocation in myc-GLUT4-mOrange-L6 cells were detected by confocal laser scanning microscopy. The results showed that AND enhanced the uptake of glucose, GLUT4 expression and fusion with plasma membrane in L6 cells. Meanwhile, AND also significantly activated the phosphorylation of AMPK and PKC and increased the concentration of intracellular Ca2+. AND-induced GLUT4 expression was significantly inhibited by a PKC inhibitor (Gö6983). In addition, in the case of 0 mM extracellular Ca2+ and 0 mM extracellular Ca2+ + 10 μM BAPTA-AM (intracellular Ca2+ chelator), AND induced the translocation of GLUT4, and the uptake of glucose was significantly inhibited. Therefore, we concluded that AND promoted the expression of GLUT4 and its fusion with plasma membrane in L6 cells through PKC pathways in a Ca2+—dependent manner, thereby increasing the uptake of glucose.

Effect of Carica papaya on IRS-1/Akt Signaling Mechanisms in High-Fat-Diet-Streptozotocin-Induced Type 2 Diabetic Experimental Rats: A Mechanistic Approach

Despite rigorous endeavors, existing attempts to handle type 2 diabetes (T2DM) are still a long way off, as a substantial number of patients do not meet therapeutic targets. Insulin resistance in skeletal muscle is discerned as a forerunner in the pathogenesis of T2DM and can be detected years before its progress. Studies have revealed the antidiabetic properties of Carica papaya (C. papaya), but its molecular mechanism on insulin receptor substrate-1 (IRS-1)/Akt signaling mechanisms is not yet known. The present study aimed to evaluate the role of C. papaya on IRS1 and Akt in high-fat-diet-streptozotocin-induced type 2 diabetic rats and also to analyze the bioactive compounds of C. papaya against IRS-1 and Akt via in silico analysis. Ethanolic extract of the leaves of C. papaya (600 mg/kg of body weight) was given daily for 45 days postinduction of T2DM up to the end of the study. Gluconeogenic enzymes, glycolytic enzymes, gene expression, and immunohistochemical analysis of IRS-1 and Akt in skeletal muscle were evaluated. C. papaya treatment regulated the levels of gluconeogenic and glycolytic enzymes and the levels of IRS-1 and Akt in skeletal muscle of type 2 diabetic animals. In silico studies showed that trans-ferulic acid had the greatest hit rate against the protein targets IRS-1 and Akt. C. papaya restored the normoglycemic effect in diabetic skeletal muscle by accelerating the expression of IRS-1 and Akt.

Protein O-GlcNAcylation in Metabolic Modulation of Skeletal Muscle: A Bright but Long Way to Go

O-GlcNAcylation is an atypical, dynamic and reversible O-glycosylation that is critical and abundant in metazoan. O-GlcNAcylation coordinates and receives various signaling inputs such as nutrients and stresses, thus spatiotemporally regulating the activity, stability, localization and interaction of target proteins to participate in cellular physiological functions. Our review discusses in depth the involvement of O-GlcNAcylation in the precise regulation of skeletal muscle metabolism, such as glucose homeostasis, insulin sensitivity, tricarboxylic acid cycle and mitochondrial biogenesis. The complex interaction and precise modulation of O-GlcNAcylation in these nutritional pathways of skeletal muscle also provide emerging mechanical information on how nutrients affect health, exercise and disease. Meanwhile, we explored the potential role of O-GlcNAcylation in skeletal muscle pathology and focused on its benefits in maintaining proteostasis under atrophy. In general, these understandings of O-GlcNAcylation are conducive to providing new insights into skeletal muscle (patho) physiology.

Jiangtang Sanhao formula ameliorates skeletal muscle insulin resistance via regulating GLUT4 translocation in diabetic mice

Jiangtang Sanhao formula (JTSHF), one of the prescriptions for treating the patients with diabetes mellitus (DM) in traditional Chinese medicine clinic, has been demonstrated to effectively ameliorate the clinical symptoms of diabetic patients with overweight or hyperlipidemia. The preliminary studies demonstrated that JTSHF may enhance insulin sensitivity and improve glycolipid metabolism in obese mice. However, the action mechanism of JTSHF on skeletal muscles in diabetic mice remains unclear. To this end, high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic mice were subjected to JTSHF intervention. The results revealed that JTSHF granules could reduce food and water intake, decrease body fat mass, and improve glucose tolerance, lipid metabolism, and insulin sensitivity in the skeletal muscles of diabetic mice. These effects may be linked to the stimulation of GLUT4 expression and translocation via regulating AMPKα/SIRT1/PGC-1α signaling pathway. The results may offer a novel explanation of JTSHF to prevent against diabetes and IR-related metabolic diseases.

Network pharmacology-based strategy for predicting therapy targets of Sanqi and Huangjing in diabetes mellitus

BACKGROUND

A comprehensive literature search shows that Sanqi and Huangjing (SQHJ) can improve diabetes treatment in vivo and in vitro, respectively. However, the combined effects of SQHJ on diabetes mellitus (DM) are still unclear.

AIM

To explore the potential mechanism of Panax notoginseng (Sanqi in Chinese) and Polygonati Rhizoma (Huangjing in Chinese) for the treatment of DM using network pharmacology.

METHODS

The active components of SQHJ and targets were predicted and screened by network pharmacology through oral bioavailability and drug-likeness filtration using the Traditional Chinese Medicine Systems Pharmacology Analysis Platform database. The potential targets for the treatment of DM were identified according to the DisGeNET database. A comparative analysis was performed to investigate the overlapping genes between active component targets and DM treatment-related targets. We constructed networks of the active component-target and target pathways of SQHJ using Cytoscape software and then analyzed the gene functions. Using the STRING database to perform an interaction analysis among overlapping genes and a topological analysis, the interactions between potential targets were identified. Gene Ontology (GO) function analyses and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were conducted in DAVID.

RESULTS

We screened 18 active components from 157 SQHJ components, 187 potential targets for active components and 115 overlapping genes for active components and DM. The network pharmacology analysis revealed that quercetin, beta-sitosterol, baicalein, etc. were the major active components. The mechanism underlying the SQHJ intervention effects in DM may involve nine core targets (TP53, AKT1, CASP3, TNF, interleukin-6, PTGS2, MMP9, JUN, and MAPK1). The screening and enrichment analysis revealed that the treatment of DM using SQHJ primarily involved 16 GO enriched terms and 13 related pathways.

CONCLUSION

SQHJ treatment for DM targets TP53, AKT1, CASP3, and TNF and participates in pathways in leishmaniasis and cancer.

O-GlcNAcylation: The Underestimated Emerging Regulators of Skeletal Muscle Physiology

O-GlcNAcylation is a highly dynamic, reversible and atypical glycosylation that regulates the activity, biological function, stability, sublocation and interaction of target proteins. O-GlcNAcylation receives and coordinates different signal inputs as an intracellular integrator similar to the nutrient sensor and stress receptor, which target multiple substrates with spatio-temporal analysis specifically to maintain cellular homeostasis and normal physiological functions. Our review gives a brief description of O-GlcNAcylation and its only two processing enzymes and HBP flux, which will help to better understand its physiological characteristics of sensing nutrition and environmental cues. This nutritional and stress-sensitive properties of O-GlcNAcylation allow it to participate in the precise regulation of skeletal muscle metabolism. This review discusses the mechanism of O-GlcNAcylation to alleviate metabolic disorders and the controversy about the insulin resistance of skeletal muscle. The level of global O-GlcNAcylation is precisely controlled and maintained in the "optimal zone", and its abnormal changes is a potential factor in the pathogenesis of cancer, neurodegeneration, diabetes and diabetic complications. Although the essential role of O-GlcNAcylation in skeletal muscle physiology has been widely studied and recognized, it still is underestimated and overlooked. This review highlights the latest progress and potential mechanisms of O-GlcNAcylation in the regulation of skeletal muscle contraction and structural properties.

Panax notoginseng saponins reverse P-gp-mediated steroid resistance in lupus: involvement in the suppression of the SIRT1/FoxO1/MDR1 signalling pathway in lymphocytes

Background

P-glycoprotein (P-gp)-mediated steroid resistance (SR) has been suggested to play a significant role in lupus nephritis (LN) treatment failure. Panax notoginseng saponins (PNS), the main effective components of the traditional Chinese medicine notoginseng, exhibited potent reversal capability of P-gp-mediated SR, but its mechanism remains unknown. This study aimed to investigate the effect of PNS on reversing SR in lupus and its underlying mechanism in vivo and in vitro.

Methods

In this study, an SR animal and splenic lymphocyte model were established using low-dose methylprednisolone (MP). Flow cytometry was used to detect the effect of PNS on reversing P-gp-mediated SR and the expression of P-gp in different T-cells phenotypes. Serum levels of ANA and dsDNA in lupus mice were measured by ELISA. Apoptosis was identified by Annexin V-FITC/PI staining. RT–PCR and Western blotting were used to detect the protein and mRNA expression levels of SIRT1, FoxO1, and MDR1 in SR splenic lymphocytes from lupus mice (SLCs/MPs).

Results

PNS could reverse the SR in lupus mice. Simultaneously, PNS increased the apoptotic effect of MP on SLCs/MP cells. The increased accumulation of rhodamine-123 (Rh-123) indicated that intracellular steroid accumulation could be increased by the action of PNS. Moreover, PNS decreased the expression of P-gp levels. Further experiments elucidated that the SIRT1/FoxO1/MDR1 signalling pathway existed in SLCs/MP cells, and PNS suppressed its expression level to reverse SR. The expression of P-gp in Th17 from SLCs/MP cells was increased, while PNS could reduce its level in a more obvious trend.

Conclusion

The present study suggested that PNS reversed P-gp-mediated SR via the SIRT1/FoxO1/MDR1 signalling pathway, which might become a valuable drug for the treatment of SR in lupus. Th17 might be the main effector cell of PNS reversing SR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03499-5.

Potential Application of Cornelian Cherry Extract on Broiler Chickens: Growth, Expression of Antioxidant Biomarker and Glucose Transport Genes, and Oxidative Stability of Frozen Meat

Simple Summary

Supplementation of the poultry diet with plant extracts rich in polyphenolic compounds could improve the performance of animals as well as the oxidative stability of their derived meat. The present study evaluated the efficacy of cornelian cherry extract (CCE) on the expression of genes controlling glucose transporters and different assays regulating the oxidative stability of frozen, stored meat over a long period of time (90 days of storage). The results indicated that the addition of 200 mg/kg of CCE to the diet could improve the growth rate and antioxidant status of broiler chickens and thus increase their productivity. Moreover, polyphenolic compounds rich in CCE can act as antioxidant agents to increase the shelf-life extension of frozen, stored poultry meat. Finally, supplementation with CCE could increase the total concentration of phenolic compounds in poultry meat offered to human consumers.

Abstract

The use of natural plant extracts in poultry feed could improve their productivity as well as the oxidative stability of stored derived meat. The roles of cornelian cherry extract (CCE) in growth, cecal microbes, and meat antioxidative markers of broiler chickens were evaluated. A total of 500 Ross 308 broiler chicks were fed diets supplemented with CCE (0, 50, 100, 200, 400 mg/kg of diet) for 38 days. The highest levels of weight gain and feed utilization were observed in a group fed 200 mg/kg of CCE. Maximum upregulation of glucose transporters—1 and 2 and sodium-dependent glucose transporter genes—were found in the group fed 200 mg/kg of CCE. Lactobacilli and Bifidobacterium colonization increased as the CCE levels increased. The greatest upregulation of antioxidant genes (glutathione peroxidase, catalase, and superoxide dismutase) in breast meat was observed in groups fed CCE (200 and 400 mg/kg). Dietary CCE significantly delayed the lipid oxidation of breast meat compared with that of the control group. The total phenolic content, 2,2-Diphenyl-1-Picrihydrzyl (DPPH) radical scavenging activity and reducing power in meat improved with higher levels of CCE. Dietary CCE improved the growth, performance of broilers, and meat antioxidant stability after 90 days of storage.

Tian-Huang Formula, a Traditional Chinese Medicinal Prescription, Improves Hepatosteatosis and Glucose Intolerance Targeting AKT-SREBP Nexus in Diet-Induced Obese Rats

The progressive increase of metabolic diseases underscores the necessity for developing effective therapies. Although we found Tian-Huang formula (THF) could alleviate metabolic disorders, the underlying mechanism remains to be fully understood. In the present study, firstly, male Sprague-Dawley rats were fed with high-fat diet plus high-fructose drink (HFF, the diet is about 60% of calories from fat and the drink is 12.5% fructose solution) for 14 weeks to induce hepatosteatosis and glucose intolerance and then treated with THF (200 mg/kg) for 4 weeks. Then, metabolomics analysis was performed with rat liver samples and following the clues illustrated by Ingenuity Pathway Analysis (IPA) with the metabolomics discoveries, RT-qPCR and Western blotting were carried out to validate the putative pathways. Our results showed that THF treatment reduced the body weight from 735.1 ± 81.29 to 616.3 ± 52.81 g and plasma triglyceride from 1.5 ± 0.42 to 0.88 ± 0.33 mmol/L; meanwhile, histological examinations of hepatic tissue and epididymis adipose tissue showed obvious alleviation. Compared with the HFF group, the fasting serum insulin and blood glucose level of the THF group were improved from 20.77 ± 6.58 to 9.65 ± 5.48 mIU/L and from 8.96 ± 0.56 to 7.66 ± 1.25 mmol/L, respectively, so did the serum aspartate aminotransferase, insulin resistance index, and oral glucose tolerance (p = 0.0019, 0.0053, and 0.0066, respectively). Furthermore, based on a list of 32 key differential endogenous metabolites, the molecular networks generated by IPA suggested that THF alleviated glucose intolerance and hepatosteatosis by activating phosphatidylinositol-3 kinase (PI3K) and low-density lipoprotein receptor (LDL-R) involved pathways. RT-qPCR and Western blotting results confirmed that THF alleviated hepatic steatosis and glucose intolerance partly through protein kinase B- (AKT-) sterol regulatory element-binding protein (SREBP) nexus. Our findings shed light on molecular mechanisms of THF on alleviating metabolic diseases and provided further evidence for developing its therapeutic potential.

Effect of Panax notoginseng Saponins and Major Anti-Obesity Components on Weight Loss

The prevalence of individuals who are overweight or obese is rising rapidly globally. Currently, majority of drugs used to treat obesity are ineffective or are accompanied by obvious side effects; hence, the options are very limited. Therefore, it is necessary to find more effective and safer anti-obesity drugs. It has been proven in vivo and in vitro that the active ingredient notoginsenosides isolated from traditional Chinese medicine Panax notoginseng (Burk.) F. H. Chen exhibits anti-obesity effects. Notoginsenosides can treat obesity by reducing lipid synthesis, inhibiting adipogenesis, promoting white adipose tissue browning, increasing energy consumption, and improving insulin sensitivity. Although notoginsenosides are potential drugs for the treatment of obesity, their effects and mechanisms have not been analyzed in depth. In this review, the anti-obesity potential and mechanism of action of notoginsenosides were analyzed; thus laying emphasis on the timely prevention and treatment of obesity.

Qihu Preparation Ameliorates Diabetes by Activating the AMPK Signaling Pathway in db/db Mice

PURPOSE

To examine the pharmacological effects of Qihu on type 2 diabetes mellitus using db/db mice.

MATERIALS AND METHODS

Thirty-seven db/db mice were randomly divided into the following 5 groups: diabetes model control group (DM group; n = 7), administered with the adjuvant 0.3% carboxymethyl cellulose-Na; positive control group (Met group; n = 8), administered with metformin (0.13 g/kg bodyweight); Qihu-L group (n = 7), administered with a low dose of Qihu (0.75 g/kg bodyweight), Qihu-M group (n = 7), administered with a medium dose of Qihu (1.5 g/kg bodyweight); Qihu-H group (n = 8), administered with a high dose of Qihu (3.0 g/kg bodyweight). BKS mice (n = 8) were used as the negative control group. The db/db mice were administered with drugs through oral gavage for 28 days. The random blood glucose levels, glucose tolerance test, bodyweight, food intake, and blood lipid levels of the mice were measured during the experimental period. The liver and pancreas tissues were collected for pathological, quantitative real-time polymerase chain reaction, and Western blotting analyses.

RESULTS

Compared with the DM group, the Qihu groups exhibited decreased bodyweight gain. The blood glucose levels in the Qihu-L, Qihu-M, and Qihu-H were 31.46%, 43.73%, and 51.83%, respectively, lower than those in the DM group. The triglyceride levels were significantly downregulated and the swelling and steatosis of the hepatocytes were significantly lower in the Qihu-M and Qihu-H groups than in the DM group. Qihu downregulated the expression of IL-1β, IL-6, and TXNIP and upregulated the AMP-activated protein kinase (AMPK) signaling pathway in the pancreas and liver tissues of db/db mice.

CONCLUSION

The anti-diabetic effects of Qihu are mediated through the activation of the AMPK/Txnip signaling and the downregulation of the secretion of inflammatory factors in db/db mice.

The regulatory role of dietary factors in skeletal muscle development, regeneration and function

Skeletal muscle plays a crucial role in motor function, respiration, and whole-body energy homeostasis. How to regulate the development and function of skeletal muscle has become a hot research topic for improving lifestyle and extending life span. Numerous transcription factors and nutritional factors have been clarified are closely associated with the regulation of skeletal muscle development, regeneration and function. In this article, the roles of different dietary factors including green tea, quercetin, curcumin (CUR), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and resveratrol (RES) in regulating skeletal muscle development, muscle mass, muscle function, and muscle recovery have been summarized and discussed. We also reviewed the potential regulatory molecular mechanism of these factors. Based on the current findings, dietary factors may be used as a potential therapeutic agent to treat skeletal muscle dysfunction as well as its related diseases.

Panax notoginseng saponins modulate the gut microbiota to promote thermogenesis and beige adipocyte reconstruction via leptin-mediated AMPKα/STAT3 signaling in diet-induced obesity

Background: Activation of the thermogenic program in white and brown adipocytes presents a promising avenue for increasing energy expenditure during the treatment of obesity. The endogenous mechanism for promoting thermogenesis in brown adipocytes or browning in white adipocytes has indicated that the gut microbiota is a crucial regulator of the host energy balance. However, whether the effects of the therapeutic intervention-induced modulation of the gut microbiota on adipocyte browning involved the regulation of leptin remains unclear.

Method: The adipose features were analyzed by body composition analysis, infrared camera observations, transmission electron microscopy and H&E staining. The gene and protein expression in adipose tissue were detected by qRT-PCR, immunoblotting, immunohistochemistry and immunofluorescence staining. The gut microbiome signature was identified by 16S rRNA gene amplicon sequencing, and both mice with high-fat diet-induced obesity (DIO) and mice with antibiotics-induced microbiome depletion were subjected to fecal microbiota transplantation.

Results: Treatment with Panax notoginseng saponins (PNS) shaped the murine gut microbiome by increasing the abundances of Akkermansia muciniphila and Parabacteroides distasonis, and as a result, DIO mice harbored a distal gut microbiota with a significantly increased capacity to reduce host adiposity. The PNS-induced modulation of the gut microbiota in DIO mice could increase brown adipose tissue (BAT) thermogenesis and beige adipocyte reconstruction by activating the leptin-AMPK/STAT3 signaling pathway, which results in the promotion of energy expenditure. Leptin has an essential influence on the anti-obesity effects of PNS. In cases of leptin deficiency, the PNS-induced modulation of the gut microbiota exerts negative effects on thermogenesis and browning in white adipose tissue (WAT), which indicates that PNS fail to reduce obesity in leptin gene-deficient mice. The PNS-induced modulation of the gut microbiota exerted a minimal effect on DIO mice with antibiotic-induced microbiome depletion, which confirmed the correlation between altered gut microbiota and the remodeling of adipose tissues in DIO mice. The direct influence of leptin on browning via the AMPKα/STAT3 signaling pathway in C3H101/2 cells supported our in vivo results that signalling through the leptin-AMPK/STAT3 pathway induced by the PNS-modulated gut microbiota was involved in beige adipocyte reconstruction.

Conclusion: Our results revealed that leptin signaling is critical for alterations in microbiota-fat crosstalk and provide promising avenues for therapeutic intervention in the treatment of obesity.

Early high-fat feeding improves histone modifications of skeletal muscle at middle-age in mice

The purpose of the present study was to investigate how the effects of high-fat diet feeding on the skeletal muscle persisted during aging using mice. Post-weaned male mice were fed a high-fat diet between 1- and 3-mo-old followed by return to supply a normal diet until 13-mo-old. Monthly physical tests demonstrated that age-related glucose intolerance that was generally developed after 10-mo-old in the control mice was significantly improved in mice fed a high-fat diet. Interestingly, mRNA expressions of Pdk4, Ucp3, and Zmynd17 were up-regulated by high-fat feeding and persisted in the tibialis anterior muscle until 13-mo-old. At Pdk4 and Ucp3 loci, enhanced distributions of active histone modifications were noted in the high-fat-fed mice at 13-mo-old. In contrast, age-related accumulation of histone variant H3.3 at these loci was suppressed. These results indicated that epigenetic modifications caused by early nutrition mediated the changes in skeletal muscle gene expression during aging.

25-OH-PPD inhibits hypertrophy on diabetic cardiomyopathy via the PI3k/Akt/GSK-3β signaling pathway

The present study investigated the inhibitory effects and the associated mechanism of the compound 25-OH-PPD (PPD) on cardiac hypertrophy, fibrosis and inflammation. The signaling pathways associated with diabetic mellitus cardiomyopathy (DMCM) were investigated using a rat model. DMCM Sprague-Dawley rats were induced by injection of streptozotocin. The animals were divided into 5 groups as follows: Normal group (NG group), diabetic group, PPD treatment group, PPD/LY294002 group (inhibitor of PI3K/Akt) and PPD/LiCl group [inhibitor of glycogen synthase kinase (GSK) 3β]. The studies were carried out during the 12 weeks following induction of diabetes and the levels of plasma brain natriuretic peptide (BNP), creatine phosphokinase isoenzyme (CK-MB) were measured. In addition, the volume of myocardial collagen fraction (CVF) was tested. The expression levels of the inflammatory cytokines, including transforming growth factor beta 1 (TGF-β1), connective tissue growth factor (CTGF), cell adhesion molecules α-smooth muscle actin (α-SMA) and vascular adhesion molecule 1 (VCAM-1) and associated signaling proteins (Akt, GSK-3β) were measured by biochemical analyses. The levels of BNP and CK-MB, the volume of CVF, the expression levels of TGF-β1, CTGF, α-SMA and VCAM-1 in the diabetic group were higher compared with those of the normal control group (P<0.05). Conversely, the levels of these molecules were significantly decreased in the PPD treatment groups (P<0.05). The aforementioned effects were partially eliminated in the PPD/LY294002 and PPD/LiCl groups. In addition, PPD treatment significantly increased the expression levels of p-Akt and decreased the levels of phosphorylated GSK-3β compared with those of the DMCM group (P<0.05). The data demonstrated that the protective effects of 25-OH-PPD against DMCM may be attributed to the PI3k/Akt/GSK-3β signaling pathway, via the suppression of the α-SMA/VCAM axis and the downregulation of TGF-β1 and CTGF expression.

Effect of sidt2 Gene on Cell Insulin Resistance and Its Molecular Mechanism

BACKGROUND

Sidt2 (SID1 transmembrane family, member 2) is a multiple transmembrane lysosomal membrane protein newly discovered in our previous study. In the previous study, we used gene targeting technique to make a mouse model of sidt2 gene knockout (sidt2^-/-). It was found that sidt2^-/- mice showed elevated fasting blood glucose and impaired glucose tolerance, showing a disorder of glucose metabolism, suggesting that sidt2 may be closely related to insulin resistance. We used 3T3-L1 adipocytes, C2-C12 myoblasts, and HEPA1-6 hepatoma cells as subjects to observe the effects of sidt2 on insulin-stimulated glucose uptake and the abovementioned insulin signal transduction pathways, and then to explore the effect of sidt2 on peripheral tissue insulin resistance and its possible molecular mechanism.

METHODS

(1) Lentiviruses with sidt2 gene knockout and puromycin resistance were constructed by Crispr/cas9 vector and transfected into 3T3-L1 adipocytes, C2-C12 myoblasts, and HEPA1-6 hepatoma cells to construct sidt2 knockout cell line model. (2) Glucose uptake of 3T3-L1 adipocytes, C2-C12 myoblasts, and HEPA1-6 hepatoma cells stimulated by insulin was detected by glucose detection kit, and the results were analyzed. (3) Sidt2 knockout group and control group of 3T3-L1 adipocytes, C2-C12 myoblast, and HEPA1-6 hepatoma cells were cultured according to the routine method. The total proteins of the above cells were extracted, and the expression of PAKT (thr308), PI3-K, and PIRS-1 (ser307) in the IRS-1 signaling pathway of the three groups was detected by western blot technique.

RESULTS

(1) The sidt2 elimination models of 3T3-L1 adipocytes, C2-C12 myoblasts, and HEPA1-6 hepatoma cells were successfully constructed. (2) It was found that the glucose uptake of cells in the sidt2 knockout group was lower than that in normal group under insulin stimulation through the detection of glucose concentration in the cell culture medium. (3) It was found that the expression of PAKT (thr308) and PI3-K protein decreased and the expression of PIRS-1 (ser307) protein increased in sidt2^-/- group compared to the control group.

CONCLUSIONS

sidt2 knockout can reduce glucose uptake in peripheral tissue under insulin stimulation, which may lead to peripheral tissue insulin resistance by affecting the IRS-1 signal pathway.

Consumption of Cooked Common Beans or Saponins Could Reduce the Risk of Diabetic Complications

Several risks for diseases, such as atherosclerosis, renal diseases, and diabetes, have inextricably been linked with obesity. Nowadays, this health-risk-laden disease is being managed with assorted types of drugs, some of which guarantee modest benefits. The chronic inflammatory effect of obesity has a negative effect in insulin signaling, a situation attributable to insulin resistance that culminates in high blood sugar inputs seen in diseases such as type 2 diabetes and metabolic syndrome. Food such as beans with different bioactive compounds could reduce the risk of diabetic complications. Demand for bean products is growing because of its robust contents of several health-promoting components, eg, saponins. Saponins are characterized by containing lower glucose and cholesterol levels and have been doted with antioxidant activities, as well as anti-inflammatory and anti-diabetic effects. In this writing, the attributes of saponins in providing substantial health and nutritional benefits in humans, as well as in improving and ameliorating diabetic complications, were reviewed.

Efficiency comparison of PGBR extract and γ-oryzanol in antioxidative stress and anti-inflammatory properties against metabolic syndrome

This research aims to delineate the anti-inflammatory effect of pregerminated brown rice extract (PE) and γ-oryzanol on improving metabolic features of high-fat diet (HFD)-induced metabolic syndrome (MetS) mouse model. C57BL/6 mice were randomly divided into eight groups: regular diet (RD), HFD, HFD-combined treatment of 0.5, 5, or 10 mg kg^-1  day^-1 oral gavage γ-oryzanol, and 30, 300, or 600 mg kg^-1  day^-1 PE for 18 weeks. HFD-fed mice showed overweight, hyperglycemia, hyperlipidemia signs of metabolic disorder, and elevation of inflammatory cytokines such as IL-6, TNF-α, IFN-γ, NO, PGE2 in serum and MAPKs, transcription factor p65, iNOS, and MDA in the liver. In contrast, HFD-fed mice showed lower levels of adiponectin in serum and antiperoxidation enzymes GPx, SOD, and catalase in the liver. While HFD-fed mice cotreated with PE or γ-oryzanol, HFD-induced metabolic disorders, ROS, and inflammation were improved. The anti-MetS, antioxidative stress and anti-inflammation properties of PE were more potent than γ-oryzanol. PRACTICAL APPLICATIONS: Our study showed that PE or γ-oryzanol supplement could help control metabolic disorders, oxidative stress, chronic inflammation, and related complications.