The novel link between inflammatory enzyme C2GNT and the shedding of syndecan-1 in podocyte dysfunction

Syndecan-1 is known to be a potential contributor to sub-clinical inflammation in diabetic nephropathy (DN). Loss of syndecan-1 from the surface of podocytes is thought to lead to cell dysfunction, which leads to the detachment of viable podocytes from the glomerulus, an early feature of DN. Although the mechanisms of constitutive syndecan-1 shedding have been addressed by several studies, the pathological mechanisms are less elucidated. The aim of this investigation is to consider the role of the O-glycosylating enzyme C2GNT in syndecan-1 shedding by podocytes. Conditionally immortalised human podocytes were used to study the effect of hyperglycaemia and C2GNT knock-down on syndecan-1 shedding by these cells. Hyperglycaemia induced C2GNT activity in podocytes results in increased O-glycosylation on the surface syndecan-1 in cells treated with high glucose compared to percentage of normal glucose (219.5±145.7 vs . 100%, P<0.05). This increase in O-glycosylation is associated with an increase in the shedding of the syndecan-1 ectodomain by podocytes treated with high glucose compared to percentage of normal glucose (118.2±7.1 vs. 100%, P<0.05). Moreover, podocytes manipulated for C2GNT knockdown show reduced syndecan-1 shedding when treated with high glucose compared to wild type cells treated with high glucose (89.97±11.95 vs. 118.2±7.17, P<0.05). Our findings suggest that the activity of o-glycosylating enzyme C2GNT is raised in podocytes under diabetic conditions. We demonstrate for the first time a novel mecha nism of pathological syndecan-1 shedding induced by C2GNT activity. This excess syndecan-1 shedding by podocytes can contribute to podocyte dysfunction

Lower Fasting Muscle Mitochondrial Activity Relates to Hepatic Steatosis in Humans

OBJECTIVE Muscle insulin resistance has been implicated in the development of steatosis and dyslipidemia by changing the partitioning of postprandial substrate fluxes. Also, insulin resistance may be due to reduced mitochondrial function. We examined the association between mitochondrial activity, insulin sensitivity, and steatosis in a larger human population. RESEARCH DESIGN AND METHODS We analyzed muscle mitochondrial activity from ATP synthase flux (fATP) and ectopic lipids by multinuclei magnetic resonance spectroscopy from 113 volunteers with and without diabetes. Insulin sensitivity was assessed from M values using euglycemic-hyperinsulinemic clamps and/or from oral glucose insulin sensitivity (OGIS) using oral glucose tolerance tests. RESULTS Muscle fATP correlated negatively with hepatic lipid content and HbA1c. After model adjustment for study effects and other confounders, fATP showed a strong negative correlation with hepatic lipid content and a positive correlation with insulin sensitivity and fasting C-peptide. The negative correlation of muscle fATP with age, HbA1c, and plasma free fatty acids was weakened after adjustment. Body mass, muscle lipid contents, plasma lipoproteins, and triglycerides did not associate with fATP. CONCLUSIONS The association of impaired muscle mitochondrial activity with hepatic steatosis supports the concept of a close link between altered muscle and liver energy metabolism as early abnormalities promoting insulin resistance

Prevalence and control of cardiovascular risk factors in stable coronary artery outpatients in India compared with the rest of the world: An analysis from international CLARIFY registry

Objectives: We describe the clinical characteristics, prevalence and control of coronary artery disease (CAD) risk factors of the Indian cohort enrolled in the CLARIFY registry and compare them with data from rest of the world (ROW). Methods: CLARIFY is an international, prospective, observational, longitudinal cohort study in stable CAD outpatients. The baseline data of Indian cohort (n = 709) were compared to ROW (n = 31994). Results: The CLARIFY India patients were significantly younger than the ROW (59.6 ± 10.9 vs 64.3 ± 10.4). Indian patients were more likely than those in ROW to have diabetes (42.9% vs 28.8%) and angina (27.8% vs 21.9%). Mean heart rate was significantly greater in Indians measured by either palpatory method (76.1 ± 10.4 vs 68.0 ± 10.5) or ECG (74.9 ± 12.9 vs 67.0 ± 11.3). The use of aspirin (85.6% vs 87.8%), β-blockers (69.4% vs 75.4%), and lipid-lowering agents (90% vs 92.4%) was lower in India. A significantly greater proportion of patients in India exhibited low HDL cholesterol (41.6% vs 31.2%), and heart rate ≥70 bpm (82.2% vs 48.5%). The risk factors control was poor in India with heart rate goal of ≤60 bpm achieved in 2.5%; HbA1c <7% in 9.9%; and HbA1c <6.5% in 4.6% patients. Conclusion: The CLARIFY registry demonstrates a high prevalence and poor control of cardiovascular risk factors in Indian patients. Systematic efforts to improve risk factor control are required

The novel link between inflammatory enzyme C2GNT and the shedding of syndecan-1 in podocyte dysfunction

Syndecan-1 is known to be a potential contributor to sub-clinical inflammation in diabetic nephropathy (DN). Loss of syndecan-1 from the surface of podocytes is thought to lead to cell dysfunction, which leads to the detachment of viable podocytes from the glomerulus, an early feature of DN. Although the mechanisms of constitutive syndecan-1 shedding have been addressed by several studies, the pathological mechanisms are less elucidated. The aim of this investigation is to consider the role of the O-glycosylating enzyme C2GNT in syndecan-1 shedding by podocytes. Conditionally immortalised human podocytes were used to study the effect of hyperglycaemia and C2GNT knock-down on syndecan-1 shedding by these cells. Hyperglycaemia induced C2GNT activity in podocytes results in increased O-glycosylation on the surface syndecan-1 in cells treated with high glucose compared to percentage of normal glucose (219.5±145.7 vs . 100%, P<0.05). This increase in O-glycosylation is associated with an increase in the shedding of the syndecan-1 ectodomain by podocytes treated with high glucose compared to percentage of normal glucose (118.2±7.1 vs. 100%, P<0.05). Moreover, podocytes manipulated for C2GNT knockdown show reduced syndecan-1 shedding when treated with high glucose compared to wild type cells treated with high glucose (89.97±11.95 vs. 118.2±7.17, P<0.05). Our findings suggest that the activity of o-glycosylating enzyme C2GNT is raised in podocytes under diabetic conditions. We demonstrate for the first time a novel mecha nism of pathological syndecan-1 shedding induced by C2GNT activity. This excess syndecan-1 shedding by podocytes can contribute to podocyte dysfunction

Lower serum extracellular superoxide dismutase levels are associated with polyneuropathy in recent-onset diabetes

Increased oxidative stress is implicated in the pathogenesis of experimental diabetic neuropathy, but translational evidence in recent-onset diabetes is scarce. We aimed to determine whether markers of systemic oxidative stress are associated with diabetic sensorimotor polyneuropathy (DSPN) in recent-onset diabetes. In this cross-sectional study, we measured serum concentrations of extracellular superoxide dismutase (SOD3), thiobarbituric acid reactive substances (TBARS), and reduced glutathione (GSH) in 107 type 1 and 215 type 2 diabetes patients from the German Diabetes Study baseline cohort and 37 glucose-tolerant individuals (controls). DSPN was defined by electrophysiological and clinical criteria (Toronto Consensus, 2011). SOD3 and GSH concentrations were lower in individuals with type 1 and type 2 diabetes compared with concentrations in controls (P&lt;0.0001). In contrast, the TBARS concentration was higher in participants with type 1 diabetes and type 2 diabetes compared with levels in controls (P&lt;0.0001). In addition, the SOD3 concentration was higher in participants with type 1 diabetes compared to concentrations in those with type 2 diabetes (P&lt;0.0001). A low SOD3 concentration was associated with DSPN in individuals with type 1 diabetes (β=−0.306, P=0.002), type 2 diabetes (β=−0.164, P=0.017), and in both groups combined (β=−0.206, P=0.0003). Lower SOD3 concentrations were associated with decreased motor nerve conduction velocity (NCV) in men and, to a lesser degree, with reduced sensory NCV in women with diabetes. In conclusion, several biomarkers of oxidative stress are altered in recent-onset diabetes, with only a lower SOD3 concentration being linked to the presence of DSPN, suggesting a role for reduced extracellular antioxidative defense against superoxide in the early development of DSPN

Cannabidiol Inhibits Tumorigenesis in Cisplatin-Resistant Non-Small Cell Lung Cancer via TRPV2

Chemotherapy forms the backbone of current treatments for many patients with advanced non-small-cell lung cancer (NSCLC). However, the survival rate is low in these patients due to the development of drug resistance, including cisplatin resistance. In this study, we developed a novel strategy to combat the growth of cisplatin-resistant (CR) NSCLC cells. We have shown that treatment with the plant-derived, non-psychotropic small molecular weight molecule, cannabidiol (CBD), significantly induced apoptosis of CR NSCLC cells. In addition, CBD treatment significantly reduced tumor progression and metastasis in a mouse xenograft model and suppressed cancer stem cell properties. Further mechanistic studies demonstrated the ability of CBD to inhibit the growth of CR cell lines by reducing NRF-2 and enhancing the generation of reactive oxygen species (ROS). Moreover, we show that CBD acts through Transient Receptor Potential Vanilloid-2 (TRPV2) to induce apoptosis, where TRPV2 is expressed on human lung adenocarcinoma tumors. High expression of TRPV2 correlates with better overall survival of lung cancer patients. Our findings identify CBD as a novel therapeutic agent targeting TRPV2 to inhibit the growth and metastasis of this aggressive cisplatin-resistant phenotype in NSCLC

Differential Activities of the Two Closely Related Withanolides, Withaferin A and Withanone: Bioinformatics and Experimental Evidences

Background and Purpose: Withanolides are naturally occurring chemical compounds. They are secondary metabolites produced via oxidation of steroids and structurally consist of a steroid-backbone bound to a lactone or its derivatives. They are known to protect plants against herbivores and have medicinal value including anti-inflammation, anti-cancer, adaptogenic and anti-oxidant effects. Withaferin A (Wi-A) and Withanone (Wi-N) are two structurally similar withanolides isolated from Withania somnifera, also known as Ashwagandha in Indian Ayurvedic medicine. Ashwagandha alcoholic leaf extract (i-Extract), rich in Wi-N, was shown to kill cancer cells selectively. Furthermore, the two closely related purified phytochemicals, Wi-A and Wi-N, showed differential activity in normal and cancer human cells in vitro and in vivo. We had earlier identified several genes involved in cytotoxicity of i-Extract in human cancer cells by loss-of-function assays using either siRNA or randomized ribozyme library. Methodology/Principal Findings: In the present study, we have employed bioinformatics tools on four genes, i.e., mortalin, p53, p21 and Nrf2, identified by loss-of-function screenings. We examined the docking efficacy of Wi-N and Wi-A to each of the four targets and found that the two closely related phytochemicals have differential binding properties to the selected cellular targets that can potentially instigate differential molecular effects. We validated these findings by undertaking parallel experiments on specific gene responses to either Wi-N or Wi-A in human normal and cancer cells. We demonstrate that Wi-A that binds strongly to the selected targets acts as a strong cytotoxic agent both for normal and cancer cells. Wi-N, on the other hand, has a weak binding to the targets; it showed milder cytotoxicity towards cancer cells and was safe for normal cells. The present molecular docking analyses and experimental evidence revealed important insights to the use of Wi-A and Wi-N for cancer treatment and development of new anti-cancer phytochemical cocktails

Adaptation of Hepatic Mitochondrial Function in Humans with Non-Alcoholic Fatty Liver Is Lost in Steatohepatitis

SummaryThe association of hepatic mitochondrial function with insulin resistance and non-alcoholic fatty liver (NAFL) or steatohepatitis (NASH) remains unclear. This study applied high-resolution respirometry to directly quantify mitochondrial respiration in liver biopsies of obese insulin-resistant humans without (n = 18) or with (n = 16) histologically proven NAFL or with NASH (n = 7) compared to lean individuals (n = 12). Despite similar mitochondrial content, obese humans with or without NAFL had 4.3- to 5.0-fold higher maximal respiration rates in isolated mitochondria than lean persons. NASH patients featured higher mitochondrial mass, but 31%–40% lower maximal respiration, which associated with greater hepatic insulin resistance, mitochondrial uncoupling, and leaking activity. In NASH, augmented hepatic oxidative stress (H2O2, lipid peroxides) and oxidative DNA damage (8-OH-deoxyguanosine) was paralleled by reduced anti-oxidant defense capacity and increased inflammatory response. These data suggest adaptation of the liver (“hepatic mitochondrial flexibility”) at early stages of obesity-related insulin resistance, which is subsequently lost in NASH

Slit2/Robo1 signaling inhibits small‐cell lung cancer by targeting β‐catenin signaling in tumor cells and macrophages

Small‐cell lung cancer (SCLC) is an aggressive neuroendocrine subtype of lung cancer with poor patient prognosis. However, the mechanisms that regulate SCLC progression and metastasis remain undefined. Here, we show that the expression of the slit guidance ligand 2 (SLIT2) tumor suppressor gene is reduced in SCLC tumors relative to adjacent normal tissue. In addition, the expression of the SLIT2 receptor, roundabout guidance receptor 1 (ROBO1), is upregulated. We find a positive association between SLIT2 expression and the Yes1 associated transcriptional regulator (YAP1)‐expressing SCLC subtype (SCLC‐Y), which shows a better prognosis. Using genetically engineered SCLC cells, adenovirus gene therapy, and preclinical xenograft models, we show that SLIT2 overexpression or the deletion of ROBO1 restricts tumor growth in vitro and in vivo. Mechanistic studies revealed significant inhibition of myeloid‐derived suppressor cells (MDSCs) and M2‐like tumor‐associated macrophages (TAMs) in the SCLC tumors. In addition, SLIT2 enhances M1‐like and phagocytic macrophages. Molecular analysis showed that ROBO1 knockout or SLIT2 overexpression suppresses the transforming growth factor beta 1 (TGF‐β1)/β‐catenin signaling pathway in both tumor cells and macrophages. Overall, we find that SLIT2 and ROBO1 have contrasting effects on SCLC tumors. SLIT2 suppresses, whereas ROBO1 promotes, SCLC growth by regulating the Tgf‐β1/glycogen synthase kinase‐3 beta (GSK3)/β‐catenin signaling pathway in tumor cells and TAMs. These studies indicate that SLIT2 could be used as a novel therapeutic agent against aggressive SCLC