ADP-ribosylation factor-like GTPase 15 enhances insulin-induced AKT phosphorylation in the IR/IRS1/AKT pathway by interacting with ASAP2 and regulating PDPK1 activity.

Decreased phosphorylation in the insulin signalling pathway is a hallmark of insulin resistance. The causes of this phenomenon are complicated and multifactorial. Recently, genomic analyses have identified ARL15 as a new candidate gene related to diabetes. However, the ARL15 protein function remains unclear. Here, we show that ARL15 is upregulated by insulin stimulation. This effect was impaired in insulin-resistant pathophysiology in TNF-α-treated C2C12 myotubes and in the skeletal muscles of leptin knockout mice. In addition, ARL15 localized to the cytoplasm in the resting state and accumulated in the Golgi apparatus around the nucleus upon insulin stimulation. ARL15 overexpression can enhance the phosphorylation of the key insulin signalling pathway molecules IR, IRS1 and AKT in C2C12 myotubes. Moreover, ARL15 knockdown can also specifically inhibit the phosphorylation of PDPK1 Ser241, thereby reducing PDPK1 activity and its downstream phosphorylation of AKT Thr308. Co-immunoprecipitation assays identified ASAP2 as an ARL15-interacting protein. In conclusion, we have identified that ARL15 acts as an insulin-sensitizing effector molecule to upregulate the phosphorylation of members of the canonical IR/IRS1/PDPK1/AKT insulin pathway by interacting with its GAP ASAP2 and activating PDPK1. This research may provide new insights into GTPase-mediated insulin signalling regulation and facilitate the development of new pharmacotherapeutic targets for insulin sensitization.

Hemoglobin combined with triglyceride and ferritin in predicting non-alcoholic fatty liver.

BACKGROUND AND AIM: The red blood cells (RBC) count is closely associated with insulin resistance (IR), which is origin of non-alcoholic fatty liver disease (NAFLD). This study aimed to investigate the correlation of RBC indices with NAFLD. METHODS: A total of 977 cases including 446 NAFLD patients and 531 controls were enrolled and examined for biochemical and metabolic indices. RBC, hematocrit (HCT), hemoglobin (HGB), insulin, and ferritin were detected. The IR indicator latest homeostasis model assessment-insulin resistance and fatty liver index were calculated. The correlation analysis was assessed by Spearman's rank test. Receiver operating characteristic was used to evaluate diagnostic performance. After quartile classification of RBC indices, logistic regression analysis was conducted to evaluate the odds ratios (OR) of NAFLD. RESULTS: RBC, HCT, and HGB levels were obviously higher in NAFLD group. RBC, HCT, and HGB showed significant positive correlation with homeostasis model assessment-insulin resistance and NAFLD. Multivariate analysis revealed HGB, ferritin, and triglyceride (TG) as independent parameters associated with NAFLD. The predictive value after combination of HGB with ferritin and TG was equal to fatty liver index. After adjustment for age,body mass index, systolic blood pressure, total cholesterol, TG, low-density lipoprotein, high-density lipoprotein and smoking, comparing the groups with the highest and lowest HGB, HCT, and RBC, the OR (95% confidence intervals) of NAFLD were 2.369 (1.279-4.368) (P < 0.05), 1.504 (0.819-2.713) (P > 0.05), and 2.332 (0.823-2.550) (P > 0.05) in men. In women, the OR were 2.541 (1.118-5.771), 3.578 (1.464-8.748), and 3.215 (1.387-7.455) (P < 0.05). CONCLUSIONS: Our data suggest that HGB combined with TG and ferritin may serve as the indicator of predicting NAFLD.

Mortality prediction in patients with hyperglycaemic crisis using explainable machine learning: a prospective, multicentre study based on tertiary hospitals.

BACKGROUND: Experiencing a hyperglycaemic crisis is associated with a short- and long-term increased risk of mortality. We aimed to develop an explainable machine learning model for predicting 3-year mortality and providing individualized risk factor assessment of patients with hyperglycaemic crisis after admission. METHODS: Based on five representative machine learning algorithms, we trained prediction models on data from patients with hyperglycaemic crisis admitted to two tertiary hospitals between 2016 and 2020. The models were internally validated by tenfold cross-validation and externally validated using previously unseen data from two other tertiary hospitals. A SHapley Additive exPlanations algorithm was used to interpret the predictions of the best performing model, and the relative importance of the features in the model was compared with the traditional statistical test results. RESULTS: A total of 337 patients with hyperglycaemic crisis were enrolled in the study, 3-year mortality was 13.6% (46 patients). 257 patients were used to train the models, and 80 patients were used for model validation. The Light Gradient Boosting Machine model performed best across testing cohorts (area under the ROC curve 0.89 [95% CI 0.77-0.97]). Advanced age, higher blood glucose and blood urea nitrogen were the three most important predictors for increased mortality. CONCLUSION: The developed explainable model can provide estimates of the mortality and visual contribution of the features to the prediction for an individual patient with hyperglycaemic crisis. Advanced age, metabolic disorders, and impaired renal and cardiac function were important factors that predicted non-survival. TRIAL REGISTRATION NUMBER: ChiCTR1800015981, 2018/05/04.

Sfrp5 expression and secretion in adipocytes are up-regulated during differentiation and are negatively correlated with insulin resistance.

We have examined the patterns of Sfrp5 (secreted frizzled-related protein 5) mRNA expression and protein secretion during adipocyte differentiation, and investigated the potential role of Sfrp5 in IR (insulin resistance) in adipocytes. 3T3-L1 pre-adipocytes were induced for differentiation, and RT-PCR (reverse transcription-PCR) and ELISA assays were used to determine Sfrp5 mRNA expression and protein secretion. The results showed that with the differentiation and maturity of pre-adipocytes, transcription and protein secretion of Sfrp5 gradually increased, peaking on the 9th day of differentiation. Sfrp5 mRNA expression in mature adipocytes was decreased by 20, 22 and 32 upon treatment with dexamethasone, insulin and TNF (tumour necrosis factor) respectively, whereas Sfrp5 protein secretion was decreased by 15, 17 and 30%, correspondingly. In contrast, Sfrp5 mRNA expression in mature adipose was increased by 34 and 19% upon treatment with rosiglitazone and metformin respectively, whereas Sfrp5 protein secretion was increased by 10 and 6%, correspondingly. In conclusion, Sfrp5 mRNA expression and protein secretion depend on the differentiation of adipocytes. The dysregulation of Sfrp5 expression and secretion is directly correlated with IR. Up-regulation of Sfrp5 expression and secretion in adipocytes may be one crucial mechanism by which rosiglitazone and metformin improve insulin sensitivity.

The impact of hyperglycaemic crisis episodes on long-term outcomes for inpatients presenting with acute organ injury: A prospective, multicentre follow-up study.

Background: The long-term clinical outcome of poor prognosis in patients with diabetic hyperglycaemic crisis episodes (HCE) remains unknown, which may be related to acute organ injury (AOI) and its continuous damage after hospital discharge. This study aimed to observe the clinical differences and relevant risk factors in HCE with or without AOI. Methods: A total of 339 inpatients were divided into an AOI group (n=69) and a non-AOI group (n=270), and their differences and risk factors were explored. The differences in clinical outcomes and prediction models for evaluating the long-term adverse events after hospital discharge were established. Results: The mortality among cases complicated by AOI was significantly higher than that among patients without AOI [8 (11.59%) vs. 11 (4.07%), Q = 0.034] during hospitalization. After a 2-year follow-up, the mortality was also significantly higher in patients with concomitant AOI than in patients without AOI after hospital discharge during follow-up [13 (21.31%) vs. 15 (5.8%), Q < 0.001]. The long-term adverse events in patients with concomitant AOI were significantly higher than those in patients without AOI during follow-up [15 (24.59%) vs. 31 (11.97%), Q = 0.015]. Furthermore, Blood ß-hydroxybutyric acid (P = 0.003), Cystatin C (P <0.001), serum potassium levels (P = 0.001) were significantly associated with long-term adverse events after hospital discharge. Conclusions: The long-term prognosis of HCE patients complicated with AOI was significantly worse than that of HCE patients without AOI. The laboratory indicators were closely correlated with AOI, and future studies should explore the improvement of clinical outcome in response to timely interventions.

PPARγ attenuates hepatic inflammation and oxidative stress of non­alcoholic steatohepatitis via modulating the miR­21­5p/SFRP5 pathway.

Inflammation and oxidative stress are key steps in the progression of non­alcoholic steatohepatitis (NASH). Intervention in these two processes will therefore benefit NASH treatment. Peroxisome proliferator­activated receptor Î³ (PPARγ), as a multiple functional transcription factor, has been reported to be involved in the prevention of NASH progression. However, the mechanism by which PPARγ prevents NASH remains to be elucidated. The present study demonstrated that the level of PPARγ was inversely correlated with that of microRNA (miRNA/miRs)­21­5p in both mice and humans with NASH. Activation of PPARγ inhibited lipid droplet accumulation, hepatic inflammation and oxidative stress by downregulating miR­21­5p in an in vitro model. Luciferase reporter and chromatin immunoprecipitation assays demonstrated that PPARγ suppressed transcriptional activity of miR­21­5p and bound to miR­21­5p promoter region. Furthermore, PPARγ downregulated miR­21­5p while miR­21­5p upregulated secreted frizzled­related protein 5 (SFRP5) by targeting the 3'­UTR of its mRNA. In vivo experiments revealed that PPARγ repressed inflammation and oxidative stress and miR­21­5p expression while increased SFRP5 level in a NASH mouse model. In summary, PPARγ attenuates inflammation and oxidative stress in NASH by modulating the miR­21­5p/SFRP5 pathway, thus holding promise of a new target for NASH treatment.

Inwardly rectifying potassium channel 5.1: Structure, function, and possible roles in diseases.

Inwardly rectifying potassium (Kir) channels make it easier for K+ to enter into a cell and subsequently regulate cellular biological functions. Kir5.1 (encoded by KCNJ16) alone can form a homotetramer and can form heterotetramers with Kir4.1 (encoded by KCNJ10) or Kir4.2 (encoded by KCNJ15). In most cases, homomeric Kir5.1 is non-functional, while heteromeric Kir5.1 on the cell membrane contributes to the inward flow of K+ ions, which can be regulated by intracellular pH and a variety of signaling mechanisms. In the form of a heterotetramer, Kir5.1 regulates Kir4.1/4.2 activity and is involved in the maintenance of nephron function. Actually, homomeric Kir5.1 may also play a very important role in diseases, including in the ventilatory response to hypoxia and hypercapnia, hearing impairment, cardiovascular disease and cancer. With an increase in the number of studies into the roles of Kir channels, researchers are paying more attention to the pathophysiological functions of Kir5.1. This minireview provides an overview regarding these Kir5.1 roles.

Distribution, development and proliferation of interstitial cells of Cajal in murine colon: an immunohistochemical study from neonatal to adult life.

This paper aimed at investigating the alterations in interstitial cells of Cajal (ICC) in the proximal, middle and distal colon of mice from 0-day to 56-day post-partum (P0-P56) by immunohistochemistry. The Kit(+) ICC, which situated around myenteric nerve plexus (ICC-MY) were prominent at birth, meanwhile those cells within the smooth muscle layers (ICC-IM) and in the connective tissue beneath serosa (ICC-SS) began to appear. ICC-SM, which located at the submucosal border of circular muscle layer emerged at P6 in the proximal colon and subsequently in the distal colon at P8, and ICC in the oral side of colon revealed an earlier development in morphology and a higher density than that in the anal side. The density of ICC altered obviously during postnatal period, and the estimated total amount of ICC increased approximately 30 folds at P56 than that at P0. Some Kit(+)/Ki67(+) and Kit(+)/BrdU(+) cells were observed in ICC-MY, ICC-IM and ICC-SS, but not in ICC-SM from P0 to P24. Our result indicates a proximal to distal and transmural gradient development of ICC in the postnatal colon along with a dramatic increase of ICC cell number from neonatal to adult life, and an age-dependent proliferation of ICC is also involved.

Increased levels of serum pigment epithelium-derived factor aggravate proteinuria via induction of podocyte actin rearrangement.

PURPOSE: To assess the role of serum pigment epithelium-derived factor (PEDF) in the occurrence and development of proteinuria and renal dysfunction and determine its relevant signaling pathway. METHODS: We analyzed serum PEDF, creatinine, the urinary albumin-to-creatinine ratio, and renal morphology of normal or streptozotocin (STZ)-induced diabetic mice, before and after treatment with PEDF. In vitro, podocytes were stimulated with PEDF under normal or high-glucose conditions; permeability was measured by the transwell assay with fluorescein isothiocyanate (FITC)-dextran; and F-actin cytoskeleton was analyzed by phalloidin staining. Apoptosis was assessed by flow cytometry. RhoA activity and ROCK1, ZO-1, nephrin, and podocin levels were detected by Western blotting. RESULTS: Diabetic mice exhibited a high serum PEDF level. In vivo, elevated serum PEDF led to proteinuria, increased serum creatinine, and podocyte foot process fusion in normal or diabetic mice. In vitro, both high-glucose and PEDF stimulation activated the RhoA/ROCK1 pathway in podocytes and promoted cell permeability, F-actin rearrangement, and apoptosis. Inhibition of RhoA/ROCK1 alleviated the damage from these effects. CONCLUSIONS: Elevated serum PEDF aggravates the development of proteinuria and renal dysfunction by inducing F-actin arrangement, foot process fusion, and apoptosis of podocytes in both normal and diabetic mice, and this effect may be mediated by activation of the RhoA/ROCK1 pathway.

Long-Term Outcomes of BMMSC Compared with BMMNC for Treatment of Critical Limb Ischemia and Foot Ulcer in Patients with Diabetes.

We first compared long-term clinical outcomes in treating critical limb ischemia (CLI) and foot ulcer in patients with diabetes between autologous bone marrow mesenchymal stem cell (BMMSC) and bone-marrow-derived mononuclear cell (BMMNC) transplants. Forty-one patients were enrolled and followed up for 3 years. They received an 18-day standard treatment before stem cell transplantation. Patients with bilateral CLI and foot ulcer were injected intramuscularly or basally with BMMSC, BMMNC, or normal saline (NS). Cox model analysis showed significant differences in the hazard ratio (HR) for amputation with treatment by BMMSC (HR 0.21 [95% CI (0.05, 0.95)], P = 0.043), infection of foot (HR 5.30 [95% CI (1.89, 14.92)], P = 0.002), and age ≥64 (HR 3.01 [95% CI (1.11, 8.15)], P = 0.030), but no significant differences by BMMNC at 9 months after transplantation. Regarding ulcer healing and recurrence rate, the BMMSC group demonstrated a significant difference from the NS group during the 3-6 months after transplantation or healing, but the BMMNC group did not. This trial suggests that, compared with BMMNC treatment, BMMSC treatment leads to a longer time of limb salvage and blood flow improvement, and, when compared with conventional therapy, it can promote limb blood flow and ulcerative healing, and reduce ulcer recurrence and amputation within 9 months.

SFRP5 is a target gene transcriptionally regulated by PPARγ in 3T3-L1 adipocytes.

Secreted frizzled-related protein 5 (SFRP5) is a newly identified adipokine. SFRP5 expression increases during the differentiation and maturation of adipocytes, but the factors regulating SFRP5 expression during this process remain unclear. This study showed that peroxisome proliferator-activated receptor γ (PPARγ) adenovirus transfection could enhance the SFRP5 expression of 3T3-L1 adipocytes. Three potential binding sites of PPARγ in the SFRP5 promoter domain were found by bioinformatics analysis. Luciferase reporter gene assay demonstrated that PPARγ regulated the activity of the SFRP5 promoter through cis-acting elements at -2,284--1,500bp. Further experiments verified that PPARγ could specifically bind to the SFRP5 promoter at -2,284--2,263bp using chromatin immunoprecipitation and electrophoretic mobility shift assay. These results suggest that SFRP5 be a target gene of PPARγ, and its expression may be under the transcriptional regulation of PPARγ.

Atgl deficiency induces podocyte apoptosis and leads to glomerular filtration barrier damage.

Abnormal lipid metabolism, renal lipid accumulation and lipotoxicity are associated with the pathological features of glomerulopathy. However, the mechanisms by which lipid accumulation leads to the development or progression of this disease have not been fully elucidated. In this work, we have identified a role for the rate-limiting enzyme in lipolysis, adipose triglyceride lipase (ATGL; also called patatin-like phospholipase domain-containing protein 2), in renal lipid metabolism and kidney disease. ATGL-deficient (Atgl(-/-)) mice displayed albuminuria, accompanied by ectopic deposition of fat in the kidney. Magnetic resonance imaging demonstrated that the contrast agent gadopentetic acid was retained in kidney tissue, suggesting defects in the glomerular filtration barrier. Furthermore, transmission electron microscopy revealed lipid deposits in the podocyte, along with foot process fusion and morphological changes suggestive of apoptosis. Indeed, shRNA-mediated depletion of ATGL promoted podocyte apoptosis, accompanied by increased levels of intracellular reactive oxygen species (ROS) and F-actin fibre redistribution. These effects could be partially reversed by treatment with the antioxidant N-acetylcysteine. These data suggest that ATGL deficiency induces renal lipid accumulation, proteinuria and glomerular filtration barrier dysfunction and implicate increased intracellular ROS levels in inducing podocyte F-actin rearrangement, foot process fusion and apoptosis that underlie these pathological features. ENZYMES: Adipose triglyceride lipase, EC3.1.1.3.

Li-Gan-Shi-Liu-Ba-Wei-San improves non-alcoholic fatty liver disease through enhancing lipid oxidation and alleviating oxidation stress.

ETHNOPHARMACOLOGICAL RELEVANCE: Mongolian medicine is an important constituent of traditional Chinese medicine. Its representative prescription, Li-Gan-Shi-Liu-Ba-Wei-San (LGSLBWS), is widely used for long-term treatment of chronic liver disease and nonalcoholic fatty liver disease (NAFLD). AIM OF THE STUDY: This study explored the effects and mechanism of LGSLBWS on NAFLD. MATERIALS AND METHODS: NAFLD rat model was established with high-fat diet. The effects of LGSLBWS on lipid metabolism, liver function, and hepatic morphology were observed in NAFLD rats. Superoxide dismutase (SOD) and malondialdehyde (MDA) contents in the liver, as well as the expression levels of peroxisome proliferator-activated receptor (PPAR)α, PPARß, inhibitor of nuclear factor κB α(IκBα), and inducible nitric oxide synthase (iNOS) were all detected. Finally, the effects of LGSLBWS on fatty acid oxidation, PPARα, PPARß, IκBα, and iNOS were determined in HepG2 cells. RESULTS: LGSLBWS significantly reduced the fat deposition in the liver and the serum aspartate aminotransferase levels in NAFLD rats. Serum triglyceride and free fatty acid levels were reduced by LGSLBWS. Total cholesterol and triglyceride contents in the liver were also downregulated. SOD and MDA levels were increased and decreased by LGSLBWS, respectively. LGSLBWS can significantly promote fatty acid oxidation of HepG2 cells. Upregulation of PPARα, PPARß, and IκBα and downregulation of iNOS by LGSLBWS were both observed in the NAFLD model and HepG2 cells. CONCLUSIONS: LGSLBWS can significantly improve NAFLD by enhancing fatty acid oxidation and alleviating oxidative stress.

Decreased A20 mRNA and protein expression in peripheral blood mononuclear cells in patients with type 2 diabetes and latent autoimmune diabetes in adults.

AIMS: A20 is a negative regulator of nuclear factor kappa B activation and the central gatekeeper in inflammation and immunity. While its role in type 1 diabetes has been widely studied, its expression level in immune cells from type 2 diabetes (T2D) and latent autoimmune diabetes in adult (LADA) patients remains unclear. This study aimed to clarify whether the expression of A20 is altered in patients with T2D or LADA. METHODS: Quantitative real-time polymerase chain reaction and western blotting were utilized to determine the expression of A20 mRNA and protein respectively in peripheral blood mononuclear cells (PBMCs) from patients with T2D (n=36) or LADA (n=17) and sex- and age-matched healthy controls (n=34). RESULTS: The mRNA and protein expression of A20 in PBMCs from T2D and LADA patients was significantly decreased compared with healthy controls (P<0.05). Furthermore, A20 mRNA and protein expression was significantly lower in newly diagnosed T2D patients (≤1 year since diagnosis) than in patients with a long T2D duration (>1 year since diagnosis) (P<0.05). CONCLUSIONS: Our results suggest that decreased expression of A20 in PBMCs may be involved in the pathogenesis of diabetes, and targeting A20 may offer a potential therapeutic tool in the treatment of diabetes.

Serum retinol-binding protein 4 levels are elevated but do not contribute to insulin resistance in newly diagnosed Chinese hypertensive patients.

BACKGROUND: Insulin resistance (IR) is closely correlated with cardiovascular disease (CVD). Retinol-binding protein 4 (RBP4) is a novel adipokine that modulates the action of insulin in various diseases. This study addressed the relationship between RBP4 and IR in newly diagnosed essential hypertension. METHODS: Serum RBP4, anthropometric and metabolic parameters were determined in 267 newly diagnosed essential hypertensive patients not taking antihypertensive medications. The patients along with 64 control (NC) normotensive and lean subjects paired by age and sex were divided into two groups depending on body mass index (BMI), hypertension with obesity (HPO) and hypertension without obesity (HP). RESULTS: A striking difference was observed in RBP4 levels between the HP and NC groups. Significantly higher levels were noted in the HP group compared with the NC group; slightly, but not significantly, lower levels were observed in the HPO group compared with the HP group. After adjusting for BMI, WC and WHR, a modestly linear relationship was observed between RBP4 levels and SBP (r = 0.377; p = 0.00), DBP (r = 0.288; p = 0.00) and HOMA-ß(r = 0.121; p = 0.028). Multiple stepwise regression analysis showed that SBP, WHR and drinking were independently related with serum RBP4 levels. CONCLUSIONS: The results of this study indicated that RBP4 levels were increased in naive hypertensive patients; however, no differences were observed in obese or non-obese hypertensive subjects. Our data suggest for the first time that RBP4 levels are significantly increased but do not contribute to the development of IR in newly diagnosed hypertensive Chinese patients.

Transcutaneous oxygen pressure (TcPO2): a novel diagnostic tool for peripheral neuropathy in type 2 diabetes patients.

AIMS: The assessment of transcutaneous oxygen pressure (TcPO2) may serve as a non-invasive and lower-cost alternative to nerve conduction studies (NCSs) for the diagnosis of diabetic peripheral neuropathy (DPN). The aim of this study was to determine whether the measurement of TcPO2 is useful for evaluating DPN. METHODS: We performed a cross-sectional study of 381 consecutive hospitalized diabetic patients classified by clinical examination and NCS as having DPN. Anthropometric and metabolic parameters were assessed. The TcPO2 examination was performed in both supine and sitting positions. RESULTS: Three hundred and one patients had DPN. The TcPO2 in both the supine and sitting positions was highest in the Non-DPN group and lower in the confirmed DPN group than the other three groups (p<0.001). The Non-DPN group had the lowest sitting-supine position difference in TcPO2 among the groups (p<0.001). The risk factors strongly associated with DPN included sitting-supine position difference in TcPO2 (OR=4.971, p<0.001), diabetic retinopathy (DR) (odds ratio [OR]=3.794, p=0.002), and HbA1c (OR=1.534, p=0.033). The area under the curve (AUC) of the sitting-supine position difference in TcPO2 was 0.722 and revealed an optimal cut-off point for the identification of DPN (19.5 mmHg) that had a sensitivity of 0.611 and a specificity of 0.738 based on AUC analysis. CONCLUSIONS: This large study of diabetic patients confirms that the sitting-supine position difference in TcPO2 is higher in DPN patients than control subjects, indicating that TcPO2 examination is a promising valuable diagnostic tool for DPN.

Identification of novel HLA-A 0201-restricted cytotoxic T lymphocyte epitopes from Zinc Transporter 8.

Numerous evidences demonstrated that type 1 diabetes (T1D) is due to a loss of immune tolerance to islet antigens, and CD8(+) T cells play an important role in the development of T1D. Zinc Transporter 8 (ZnT8) has emerged in recent years as a target of disease-associated autoreactive T cells in human T1D. However, ZnT8-associated CTL specific-peptides have not been identified. In this study, we predicted and identified HLA-A*0201-restricted cytotoxic T lymphocyte (CTL) epitopes derived from ZnT8, and utilized it to immunize HLA-A2.1/Kb transgenic (Tg) mice. The results demonstrated that peptides of ZnT8 containing residues 107-115, 115-123 and 145-153 could elicit specific CTLs in vitro, and induce diabetes in mice. The results suggest that these specific peptides are novel HLA-A*0201-restricted CTL epitopes, and could have therapeutic potential in preventing of T1D disease.

PGC-1α prevents apoptosis in adipose-derived stem cells by reducing reactive oxygen species production in a diabetic microenvironment.

AIMS: To examine whether overexpression of peroxisome proliferator activated receptor-gamma coactivator-1 alpha (PGC-1α) can prevent apoptosis in adipose-derived stem cells (ASCs) by reducing reactive oxygen species (ROS) production and enhancing mitochondrial function in a diabetic environment. METHODS: After the isolation, expansion and characterisation of rat ASCs, we overexpressed PGC-1α in ASCs using an adenoviral vector encoding green fluorescent protein (GFP) or PGC-1α and tested the apoptotic effect under conditions of high glucose, hypoxia and serum deprivation. The production of intracellular ROS and mitochondrial ROS was evaluated using dihydroethidium and CM-H2XRos fluorescent probes. RESULTS: Under conditions of high glucose, hypoxia and serum deprivation, the overexpression of PGC-1α in ASCs decreased apoptosis and led to an increased survival rate. The ASCs modified with PGC-1α produced lower intracellular and mitochondrial ROS. The mitochondrial morphology and structure in the PGC-1α-ASC group remained relatively complete compared with the control group. CONCLUSIONS: These results reveal a crucial protective role for PGC-1α in the treatment of diabetes mellitus and its complications using stem cells therapy.

Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) enhances engraftment and angiogenesis of mesenchymal stem cells in diabetic hindlimb ischemia.

To examine whether the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a key regulator linking angiogenesis and metabolism, could enhance the engraftment and angiogenesis of mesenchymal stem cells (MSCs) in diabetic hindlimb ischemia, we engineered the overexpression of PGC-1α within MSCs using an adenoviral vector encoding green fluorescent protein and PGC-1α, and then tested the survivability and angiogenesis of MSCs in vitro and in vivo. Under the condition of hypoxia concomitant with serum deprivation, the overexpression of PGC-1α in MSCs resulted in a higher expression level of hypoxia-inducible factor-1α (Hif-1α), a greater ratio of B-cell lymphoma leukemia-2 (Bcl-2)/Bcl-2-associated X protein (Bax), and a lower level of caspase 3 compared with the controls, followed by an increased survival rate and an elevated expression level of several proangiogenic factors. In vivo, the MSCs modified with PGC-1α could significantly increase the blood perfusion and capillary density of ischemic hindlimb of the diabetic rats, which was correlated to an improved survivability of MSCs and an increased level of several proangiogenic factors secreted by MSCs. We identified for the first time that PGC-1α could enhance the engraftment and angiogenesis of MSCs in diabetic hindlimb ischemia.

Serum bone morphogenetic protein 7, insulin resistance, and insulin secretion in non-diabetic individuals.

This study was to explore the relationship of serum BMP7 with insulin secretion and metabolic parameters in non-diabetic individuals. Serum BMP7 concentrations positively correlated with HOMA2-%B (insulin secretion index) and fasting insulin. Our findings suggested that BMP7 may stimulate insulin secretion and improve islet cell function in humans.