ABSTRACT
Type 2 diabetes is a hypermetabolic disease characterized with disorders of glucose/lipid metabolism, absolute or relative lack of insulin, and can induce skeletal muscle atrophy. Hyperglycemia, hyperlipidemia, insulin resistance, and abnormal release of inflammatory factors can lead to abnormal signal transduction in skeletal muscle, thus make protein synthesis and degradation imbalance and eventually causing muscle atrophy. Under normal conditions, insulin-like growth factor 1 (IGF-1)/insulin can activate phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT). AKT not only increases protein synthesis through mammalian target protein of rapamycin (mTOR), but also phosphorylates forkhead box O (FoxO) transcription factor and then inhibits the transcription of several ubiquitin ligases (such as MAFbx/atrogin-1 and MuRF1), or autophagy related genes. The weakened IGF-1/PI3K/AKT pathway in type 2 diabetes is an important factor leading to skeletal muscle atrophy. Studies have shown that the commonly used anti-type 2 diabetic drugs have different effects in regulating the synthesis and degradation of skeletal muscle protein. Studies reported that drugs with effect of anti-diabetic muscle atrophy include thiazolidinediones, glucagon-like peptide analogs, glucose-sodium cotransporter 2 inhibitors, etc.; drugs that are still in controversial or even promote skeletal muscle atrophy include metformin, and some sulfonylurea or non-sulfonylurea insulin secretagogues. This article overviewed and analyzed the currently commonly used drugs for type 2 diabetes and summarized the related mechanisms, with the aim to provide references for the rational applications of drugs for type 2 diabetes.
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Mediator complexes involved in skeletal muscle metabolic processes have become a hot research topic in recent years. The mediator complex is a multi-protein complex which participates in transcription by bridging specific transcription factors and basal transcriptional machinery (RNA polymerase II). Mediator complexes are involved in regulating the expression of transcription factors related to skeletal muscle metabolism and muscle fiber transformation, such as PPARs and PGC1α. These mediators participate in skeletal muscle glucose metabolism by regulating glucose transporter GLUT4 and key transcription factors of metabolic pathways. In addition, they regulate metabolic diseases by regulating the expression of PPARγ, UCP-1 and other genes involved in skeletal muscle lipid metabolism and mitochondrial functions. This article reviews the mechanism and effects of mediator complexes on skeletal muscle metabolism.
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Hyperglycemia is the dominant phenotype of diabetes and the main contributor of diabetic complications. Puerarin is widely used in cardiovascular diseases and diabetic vascular complications. However, little is known about its direct effects on diabetes. The aim of our study is to investigate its antidiabetic effect in vivo and in vitro, and explore the underlying mechanism. We used type I diabetic mice induced by streptozotocin to observe the effects of puerarin on glucose metabolism. In addition, oxidative stress and hepatic mitochondrial respiratory activity were evaluated in type I diabetic mice. In vitro, glucose consumption in HepG2 cells was assayed along with the qPCR detection of glucogenesis genes expression. Moreover, ATP production was examined and phosphorylation of AMPK was determined using Western blot. Finally, the molecular docking was performed to predict the potential interaction of puerarin with AMPK utilizing program LibDock of Discovery Studio 2018 software. The results showed that puerarin improved HepG2 glucose consumption and upregulated the glucogenesis related genes expression. Also, puerarin lowered fasting and fed blood glucose with improvement of glucose tolerance in type I diabetic mice. Further mechanism investigation showed that puerarin suppressed oxidative stress and improved hepatic mitochondrial respiratory function with enhancing ATP production and activating phosphorylation of AMPK. Docking study showed that puerarin interacted with AMPK activate site and enhancing phosphorylation. Taken together, these findings indicated that puerarin exhibited the hypoglycemic effect through attenuating oxidative stress and improving mitochondrial function via AMPK regulation, which may serve as a potential therapeutic option for diabetes treatment.
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Wound healing is a complex and highly regulated process to maintaining the skin barrier function. Wounds of diabetic patients are hard or even not healing. Non-healing diabetic foot ulcers can lead to lower-extremity amputations. Diabetic wound healing problem is the main complication that leads to high disability rate of diabetes and can threaten the lives in severe cases. The healing of skin wounds requires the synergy of multiple factors to restore the injured skin to its barrier function. The mechanisms that cause it difficult to heal diabetic wounds are complex, including oxidative stress, chronic inflammation, decreased neovascularization, peripheral neuropathy, and imbalance of extracellular matrix accumulation and remodeling. This review classifies mechanisms of diabetic wound healing and provides a reference for its further research.
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G protein-coupled receptors (GPCR) are a class of receptor superfamily that exist on the surface of cell membrane. With the intensive studies on the GPCR desensitization regulator—β-arrestins, it is found that activated GPCR can not only conduct signal transduction through G protein-dependent pathway, but also mediate via non-G protein-dependent pathway. In addition to mediate endocytosis and desensitization, β-arrestins also initiate a new series of signal transduction events. Therefore, the concept of "biased transduction" was put forward: the receptor activated by a specific ligand could selectively activate a specific signaling pathway, leading the signal to be transmitted downstream along a "preferential" pathway. We call the ligand that binds to the receptor and causes biased activation "biased ligand". It is generally believed that the phenomenon of bias results from different binding modes of ligands and receptors, including multiple receptor conformations, diverse sites that downstream signal proteins bind, and signal proteins’ own conformations, etc. Here we give a brief review focusing on the mechanisms of β-arrestin-biased GPCR signal transduction and the advances in the drug development on β-arrestin biased ligands.
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Free fatty acid receptor 1 (FFAR1), also known as G protein-coupled receptor 40 (GPR40), is a receptor for diverse free fatty acids. This review aims at summarizing effects and mechanisms of FFAR1 on insulin secretion and related blood glucose and lipids metabolism. FFAR1 is involved in the occurrence and development of type 2 diabetes, but its specific mechanism has not been clarified. FFAR1 is expressed in the wide variety of issues, especially β-cells in the pancreatic islets, as well as α-cells in islets, central nervous tissue, subcutaneous fat, skeletal muscle, gastrointestinal tract, etc. FFAR1 can act on islet β-cells to promote the secretion of insulin, promote α-cells on glucagon secretion, and regulate the secretion of endocrine cells in the gastrointestinal tract to balance the level of glucose and lipids. Existing research found that FFAR1 agonists have significant advantages. They promote insulin release, reduce weight and protect pancreatic β-cells, and have no risk of hypoglycemia. To in-depth understand the role of FFAR1 as a drug target in the treatment of diabetes, further pharmacological studies are still needed in order to obtain safer and more effective drugs against type 2 diabetes.
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Carpesii Fructus is the fruit of Carpesium abrotanoides L. and is recorded in the Chinese Pharmacopoeia (2015 Edition). Carpesium abrotanoides broadly distribute in China. Traditionally, Carpesii Fructus was used as a parasiticide,especially for ascariasis,pinworms and tapeworm disease. In ancient times,the Carpesium plants were used as traditional Chinese,Korean and Japanese herbal medicines for the treatment of several diseases.Carpesii Fructus was first recorded in the book"Newly Revised Canon of Materia Medica"in the Tang Dynasty of China.The original plant is Compositae Arte-misia santonica (Seriphidium cinum) from middle east Persian. At present, Carpesium abrotanoides issometimes confused with the Lappula family in species classification. In the Song Dynasty of China,"KaiYang Materia Medica"recorded that the best Carpesii Fructus was from Persian.The main compo-nents of Carpesii Fructusare terpenes,phenolic compounds,flavonoids and coumarins. Including telekin, 3-epi-isotelekin, 11β-13-dihydro-1-epi-inuviscolide, carabrone, carabrol, terpene lactone, gerilin, carpesia, valeric acid, oleic acid, linolenic acid, thirty-one alkane, sterol, etc. The chemical components isolated from whole plants of carpesia are more than 143. In clinical practice, Carpesii Fructus is mainly used as antiparasitic drugs and usually combined with other drugs since the poor efficacy as single drug. Its toxic reaction is closely related to the dose of the drug.Carpesia,asa main component of Carpesii Fructus, might lead to adverse reactions also. At present, Major issuesof Carpesii Fructusare the lack of phar-macological research,as well as lack of in-depth study on the material basis.Therefore,further studies are needed on the drug development and clinical usuage.
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Objective To investigate the application of the fluorescein diacetate (FDA) microplate assay in cell viability detection. Methods Cells were seeded in a 96-well culture plate until detection. After incubated with FDA,the plate was detected by fluorescence microplate analyzer. The effects of FDA incubation duration,concentration,and other factors on the assay's accuracy and stability were assessed. We also compared the results of FDA with methyl thiazolyl(MTT) in terms of cell numbers and HOinjury. Results Within 0-30 minutes,the fluorescence-cell number coefficient of FDA assay increased with duration and reached 0.99 in 27-30 minutes. The optimum concentration of final FDA in this study was 10-30 μg/ml. On cell viability detection,the result of FDA method was equivalent to MTT method. As to HOinjury assay,the sensitivity of FDA method was superior to MTT on the higher concentration HOtreatment due to a relative shorter duration for detection. Conclusion As a stable and reliable method,FDA is feasible for cell variability detection under varied conditions.
Subject(s)
Humans , Biological Assay , Cell Survival , Fluoresceins , Chemistry , Fluorescence , Hydrogen Peroxide , Staining and LabelingABSTRACT
The aim of this study is to investigate the effects of the metformin on the formation of hepatic fibrosis in type 2 diabetic rats and discuss its mechanism of liver-protecting activity. After SD rats were fed with high-fat and high-sucrose diet for four weeks, low-dose streptozotocin (STZ) was injected intraperitoneally to make the animal mode of type 2 diabetes. Then, all diabetic rats was fed with the high-fat diet and metformin (ig, 100 mg x kg(-1)) was given orally to metformin group for four months. After the last administration, fasting blood glucose was determined. The livers were removed to calculate the hepatic coefficient and to make HE and Picro acid-Sirius red staining, immunohistochemistry (alpha-SMA and TGFbeta1) and TUNEL staining in order to evaluate the effect of metformin on the hepatic fibrosis. The animal model of type 2 diabetes with hepatic fibrosis was successfully made. Metformin can significantly alleviate the lesions of hepatic steatosis and fibrosis, markedly reduce the expressions of alpha-SMA and TGFbeta1 in liver tissue of type 2 diabetic rats. However, TUNEL staining result suggested that metformin could not reduce apoptosis of hepatocytes. The results suggest that metformin can inhibit the formation of hepatic fibrosis in type 2 diabetes.
Subject(s)
Animals , Female , Male , Rats , Actins , Metabolism , Apoptosis , Blood Glucose , Metabolism , Body Weight , Diabetes Mellitus, Experimental , Drug Therapy , Metabolism , Pathology , Diabetes Mellitus, Type 2 , Drug Therapy , Metabolism , Pathology , Diet, High-Fat , Hepatocytes , Pathology , Hypoglycemic Agents , Pharmacology , Therapeutic Uses , Liver , Metabolism , Pathology , Liver Cirrhosis, Experimental , Drug Therapy , Metabolism , Pathology , Metformin , Pharmacology , Therapeutic Uses , Random Allocation , Rats, Sprague-Dawley , Streptozocin , Transforming Growth Factor beta1 , MetabolismABSTRACT
Tissue samples of Fabricius' bursa collected from Nanning, Yulin, Beihai and Wuzhou in the provinces of Guangxi in China during the years of 2000-2007, were detected by a established reverse transcriptase polymerase chain reaction (RT-PCR) technique for IBDV. Viral isolation was performed on the positive samples by chicken embryo inoculation via chorio-allantoic membrane (CAM). Results showed that 27 isolates of IBDV were obtained. A set of primers were designed to amplify the vVP2 of 27 isolates by RT-PCR and the PCR products were sequenced. The sequences of all the isolates and reference viruses were analyzed and compared, and their phylogenetic trees were constructed based on the nucleotide sequences. The results indicated that isolate BH11, TZ(3), 050222, YL051, NN0603, NN0611and QX0602 etc, altogether 17 isolates, which accounted for 62.96 percent of total isolates, were identified to be very virulent IBDV (vvIBDV) and have the highest homology to vvIBDV reference strains. In the phylogenetic analysis, they are divided into 3 groups and have a long distance to commonly used vaccine stains. Isolate NN040124 and YL052 were identified as intermediate-plus virulent strains and showed a highest homology to classical strains of 52-70 and STC. 8 isolates of YLZF2, 040131 etc were identified as attenuated vaccine strains and showed a highest homology to classical strain of CU1. The results from the study demonstrated that the viruses prevailing in chickens in these 4 regions in Guangxi province in the recently 7 years were vvIBDV and their origins were complex. The antigenicity of some isolates may have been drifted.
Subject(s)
Animals , Amino Acid Sequence , Birnaviridae Infections , Epidemiology , Virology , Chickens , China , Epidemiology , Infectious bursal disease virus , Chemistry , Classification , Genetics , Molecular Epidemiology , Molecular Sequence Data , Phylogeny , Poultry Diseases , Epidemiology , Virology , Sequence Alignment , Viral Proteins , Chemistry , GeneticsABSTRACT
A novel inhibitor series for matrix metalloproteinases (MMPs) were designed and synthesized. Using succinate and malonate as zinc binding groups and long hydrophobic substituents to bind with S1' pockets, the compounds showed micromolar inhibition and selectivity for MMP-2 over others. And we found a better activity compound. It is a chance to find a better precursor of MMP-2 inhibitors with activity and bioavailability by further optimization of compounds.