Abhishek Gupta

Chronic hyperinsulinemia reduces insulin sensitivity and metabolic functions of brown adipocyte

The growing pandemics of diabetes have become a real threat to world economy. Hyperinsulinemia and insulin resistance are closely associated with the pathophysiology of type 2 diabetes. In pretext of brown adipocytes being considered as the therapeutic strategy for the treatment of obesity and insulin resistance, we have tried to understand the effect of hyperinsulinemia on brown adipocyte function. We here with for the first time report that hyperinsulinemia-induced insulin resistance in brown adipocyte is also accompanied with reduced insulin sensitivity and brown adipocyte characteristics. CI treatment decreased expression of brown adipocyte-specific markers (such as PRDM16, PGC1α, and UCP1) and mitochondrial content as well as activity. CI-treated brown adipocytes showed drastic decrease in oxygen consumption rate (OCR) and spare respiratory capacity. Morphological study indicates increased accumulation of lipid droplets in CI-treated brown adipocytes. We have further validated these findings in vivo in C57BL/6 mice implanted with mini-osmotic insulin pump for 8weeks. CI treatment in mice leads to increased body weight gain, fat mass and impaired glucose intolerance with reduced energy expenditure and insulin sensitivity. CI-treated mice showed decreased BAT characteristics and function. We also observed increased inflammation and ER stress markers in BAT of CI-treated animals. The above results conclude that hyperinsulinemia has deleterious effect on brown adipocyte function, making it susceptible to insulin resistance. Thus, the above findings have greater implication in designing approaches for the treatment of insulin resistance and diabetes via recruitment of brown adipocytes.

Adipocyte transdifferentiation and its molecular targets

According to the World Health Organization obesity is defined as the excessive accumulation of fat, which increases risk of other metabolic disorders such as insulin resistance, dyslipidemia, hypertension, cardiovascular diseases, etc. There are two types of adipose tissue, white and brown adipose tissue (BAT) and the latter has recently gathered interest of the scientific community. Discovery of BAT has opened avenues for a new therapeutic strategy for the treatment of obesity and related metabolic syndrome. BAT utilizes accumulated fatty acids for energy expenditure; hence it is seen as one of the possible alternates to the current treatment. Moreover, browning of white adipocyte on exposure to cold, as well as with some of the pharmacological agents presents exciting outcomes and indicates the feasibility of transdifferentiation. A better understanding of molecular pathways and differentiation factors, those that play a key role in transdifferentiation are of extreme importance in designing novel strategies for the treatment of obesity and associated metabolic disorders.

Significant association of TNFα and IL-6 gene with male infertility--an explorative study in Indian populations of Uttar Pradesh.

In this study were aimed to identify the association of SNPs candidate genes of TNF-α and IL-6 with hormones levels and sperm cells death in infertile subjects of Uttar Pradesh population in North India. The study population comprised, fertile donor (control group) and infertile group patients i.e. normozoospermic (idiopathic unexplained), oligozoospermic and asthenozoospermic groups, with 260 subjects in each group. Subjects were selected from the Departments of Urology, K.Gs Medical University and Urology, SGPGIMS, Lucknow, India. The allele-specific polymerase chain reaction (PCR) and PCR-RFLP were used to investigate the substitution of the guanine (G)-to-adenosine (A) at position-308 and guanine (G)-to-cytosine (C) at position-174 in the promoter regions of the TNF-α and IL-6 genes, respectively. Further their relation to male fertility and sperm function were also investigated. It was found that the substitution levels from G to A and from G to C in the TNF-α and IL-6 genes, respectively, were significantly higher in the infertile subjects as compared to that of control group. The apoptosis and necrosis levels were also higher in oligozoospermic and asthenozoospermic infertile subjects. Further it was found to be associated with increased level of reactive oxygen species as observed in oligozoospermic and asthenozoospermic subjects. However, a significant decrease in testosterone and luteinizing hormone with increased prolactin and follicle stimulating hormones was observed in infertile subjects. The study populations indicating a strong association between TNF-α G-308A and IL-6 G-174C substitution with infertile men which is further supported by allele and genotype meta-analysis and thus established it as a risk factor.

Curcumin-3,4-Dichloro Phenyl Pyrazole (CDPP) overcomes curcumin's low bioavailability, inhibits adipogenesis and ameliorates dyslipidemia by activating reverse cholesterol transport

BACKGROUNDnAdipocyte dysfunction, obesity and associated metabolic disorders are of prime healthcare concern worldwide. Among available medications, natural products and inspired molecules hold 40% space in clinically prescribed medicines. In queue, this study overcomes the drawback of curcumins low bioavailability with potent anti-adipogenic and anti-dyslipidemic activity.nnnMETHODSnTo evaluate the role of CDPP on adipocyte differentiation, 3T3-L1 adipocytes were used as an in-vitro model. Flow cytometry was performed for cell cycle analysis. Syrian golden hamsters were used to study pharmacokinetic profile and dyslipidemic activity exhibited by CDPP.nnnRESULTnCDPP was found to be a potent inhibitor of adipogenesis in-vitro. It blocked mitotic clonal expansion by causing cell cycle arrest. CDPP showed marked improvement in gastrointestinal stability and bioavailability in-vivo as compared to curcumin. Administration of CDPP (100mg/kg) significantly improved HFD induced dyslipidemic profile in hamsters and activated reverse cholesterol transport machinery.nnnCONCLUSIONnCDPP could be used as a potential drug candidate against adipogenesis and dyslipidemia with enhanced gastrointestinal stability and bioavailability.

Cucumis melo ssp. Agrestis var. Agrestis Ameliorates High Fat Diet Induced Dyslipidemia in Syrian Golden Hamsters and Inhibits Adipogenesis in 3T3-L1 Adipocytes

Background: Cucumis melo ssp. agrestis var. agrestis (CMA) is a wild variety of C. melo. This study aimed to explore anti-dyslipidemic and anti-adipogenic potential of CMA. Materials and Methods: For initial anti-dyslipidemic and antihyperglycemic potential of CMA fruit extract (CMFE), male Syrian golden hamsters were fed a chow or high-fat diet with or without CMFE (100 mg/kg). Further, we did fractionation of this CMFE into two fractions namely; CMA water fraction (CMWF) and CMA hexane fraction (CMHF). Phytochemical screening was done with liquid chromatography-mass spectrometry LC- (MS)/MS and direct analysis in real time-MS to detect active compounds in the fractions. Further, high-fat diet fed dyslipidemic hamsters were treated with CMWF and CMHF at 50 mg/kg for 7 days. Results: Oral administration of CMFE and both fractions (CMWF and CMHF) reduced the total cholesterol, triglycerides, low‐density lipoprotein cholesterol, and very low‐density lipoprotein-cholesterol levels in high fat diet-fed dyslipidemic hamsters. CMHF also modulated expression of genes involved in lipogenesis, lipid metabolism, and reverse cholesterol transport. Standard biochemical diagnostic tests suggested that neither of fractions causes any toxicity to hamster liver or kidneys. CMFE and CMHF also decreased oil-red-O accumulation in 3T3-L1 adipocytes. Conclusion: Based on these results, it is concluded that CMA possesses anti-dyslipidemic and anti-hyperglycemic activity along with the anti-adipogenic activity. SUMMARY The oral administration of Cucumis melo agrestis fruit extract (CMFE) and its fractions (CMWF and CMHF) improved serum lipid profile in HFD fed dyslipidemic hamsters. CMFE, CMWF and CMHF significantly attenuated body weight gain and eWAT hypertrophy. The CMHF decreased lipogenesis in both liver and adipose tissue. CMFE and CMHF also inhibited adipogenesis in 3T3-L1 adipocytes. Abbreviation used: CMA: Cucumis melo ssp. agrestis var. agrestis, CMFE: CMA fruit extract, CMWF: CMA water fraction, CMHF: CMA hexane fraction, FAS: Fatty acid synthase, SREBP1c: Sterol regulatory element binding protein 1c, ACC: Acetyl CoA carboxylase, LXR α: Liver X receptor α.

Saroglitazar reduces obesity and associated inflammatory consequences in murine adipose tissue

Abstract Prevailing knowledge links chronic low‐grade inflammation in the adipose tissue to obesity and its associated metabolic complications. In this study, we evaluated immunometabolic effects of a recently launched dual peroxisome proliferator‐activated receptor (PPAR) &agr; & &ggr; agonist ‘Saroglitazar’ in a mouse model of diet‐induced obesity (DIO). Body composition analysis revealed that saroglitazar treatment promoted hepatic weight gain, while attenuated epididymal white adipose tissue (eWAT) mass in DIO. In the eWAT of saroglitazar treated mice, histological analysis showed reduced adipocyte hypertrophy and matrix deposition (picrosirius red staining). Immunological profiling of stromal vascular fraction isolated from eWAT showed decreased pro‐inflammatory cells (M1 macrophages, CD4 and CD8 T‐cells) and increased anti‐inflammatory M2 macrophages. Gene expression and western blot analysis suggested that saroglitazar promoted energy expenditure machinery and attenuated inflammatory as well as fibrotic markers in eWAT during DIO. In conclusion, for the first time we are reporting immunometabolic effects of dual PPAR&agr; & &ggr; agonist saroglitazar in DIO and insulin resistance (IR). Saroglitazar exerted its beneficial effects on adipose tissue by limiting, diet‐induced adipose tissue dysfunction, adipocyte hypertrophy, adipocyte cell damage and extracellular matrix deposition in obesity.

PPP2R5B, a regulatory subunit of PP2A, contributes to adipocyte insulin resistance

Insulin resistance is associated with deregulation of insulin signaling owing to the chronic exposure of insulin (hyperinsulinemia) to the tissues. Phosphorylation and dephosphorylation events in insulin signaling pathway play an essential role in signal transduction and glucose uptake. Amongst all, Akt protein is considered to be central to the overall insulin signaling proteins. In glucose responsive tissues like adipose and muscles, activation of Akt is responsible for triggering GLUT4 translocation and glucose transport. Several phosphatases such as PTEN, PP2A have been reported to be involved in dephosphorylation and inactivation of Akt protein. We have identified increased PP2A activity during state of chronic hyperinsulinemia exposure along-with development of adipocyte insulin resistance. This increased phosphatase activity leads activation of cAMP/PKA axis, which in turn increased cAMP levels in insulin resistant (IR) adipocytes. Okadaic acid, an inhibitor of PP2A restored and increased insulin stimulated glucose uptake in insulin resistant (IR) and insulin sensitive (IS) adipocytes respectively. In IS adipocyte, chemical activation of PP2A through MG132 and FTY720 showed decreased insulin sensitivity corroborated with decreased Akt phosphorylation and glucose uptake. We also observed an increased expression of PP2A-B (regulatory) subunit in IR adipocytes. We found PPP2R5B, a regulatory subunit of PP2A is responsible for the dephosphorylation and inactivation of Akt protein. Increased expression of PPP2R5B was also confirmed in white adipose tissue of high fat diet induced IR mice model. Overexpression and suppression strategies confirmed the role of PPP2R5B in regulating insulin signaling. Thus, we conclude that PPP2R5B, a B subunit of PP2A is a negative regulator of Akt phosphorylation contributing partly to the chronic hyperinsulinemia induced insulin resistance in adipocytes.

Chronic hyper-leptinemia induces insulin signaling disruption in adipocytes: Implications of NOS2

Leptin, following its discovery, has developed a formidable interest in the scientific community to delineate its contribution towards overall metabolic homeostasis. Contradictory reports have been published on leptin administration effects on whole body insulin sensitivity. Following late reports, we surveyed human serum leptin levels along with other metabolic parameters including BMI and HOMA-IR. We found a positive correlation between leptin levels and insulin resistance parameters. Considering the presence of the long form of leptin receptor on adipocytes, we explored the effects of chronic physiological hyper-leptinemic exposure on adipocyte insulin sensitivity. Chronic leptin (50ng/ml) treatment in 3T3-L1 adipocytes decreased insulin-induced phosphorylation of nodal insulin signaling proteins along with reduced glucose uptake. Metabolic flux studies indicated mitochondrial dysfunction and reduced oxygen consumption rate. Leptin treatment also increased both cellular and mitochondrial superoxide levels concomitant to increased expression of nitric oxide synthase-2 (NOS2). Further, pharmacological depletion of NOS2 reversed leptin mediated effects on insulin signaling. In-vivo implantation of leptin osmotic pumps in C57BL/6 mice also decreased insulin responsiveness. Interestingly, these effects were lacking in NOS2 knockout strain. In conclusion, our studies put forward a potential link between leptin and adipocyte insulin responsiveness in an NOS2 dependent manner.

The effects of periodontal therapy on serum and salivary leptin levels in chronic periodontitis patients with normal body mass index

Abstract Summary. Leptin concentrations are altered in favour of pro health after periodontal therapy. Background. Leptin, a non-glycosylated peptide hormone, not only maintains fat stores, but is also an integral part of host defense repertoire. Leptin levels have been found to be altered in an array of inflammatory diseases including chronic periodontitis (CP), but the role of non-surgical periodontal therapy (NSPT) in altering the leptin concentrations in saliva and serum of CP patients is yet to be ascertained. The aim of the present study is to quantify leptin levels in CP patients having normal body mass index (BMI) pre-therapy as compared to periodontally healthy controls and to address whether successful NSPT alters leptin concentration in serum and saliva. Materials and methods. Twenty-two saliva (modified draining method) and serum samples (by venipuncture) were collected from CP patients with normal BMI (n = 22), before and at 4 and 12 weeks after completion of NSPT, and periodontally healthy, age- and gender-matched controls (n = 22). Leptin levels were estimated using enzyme linked immunosorbent assay kits. Results. At baseline, CP patients had significantly different periodontal clinical parameters and the leptin concentrations in saliva of CP patients were found to be significantly lower than periodontally healthy volunteers (4710.10 ± 1133.21 vs 8721.10 ± 1019.58 pg/ml) (p < 0.05), whereas in serum the leptin concentrations were significantly higher than healthy controls (10749 ± 2062.24 vs 8085.00 ± 2859.68 pg/ml). Significant improvement in periodontal parameters, serum and salivary leptin levels were observed in CP patients at 4 and 12 weeks post-therapy (p < 0.01). Conclusion. Altered concentrations of leptin in serum and saliva are observed in CP patients which can be restored in favor of health after periodontal therapy.

Ecliptal, a promising natural lead isolated from Eclipta alba modulates adipocyte function and ameliorates metabolic syndrome

ABSTRACT A swift increase has been observed in the number of individuals with metabolic syndrome worldwide. A number of natural compounds have been identified towards combating metabolic syndrome. Adding to this premise, here we report the pleiotropic activities of Ecliptal (EC); a natural compound isolated from the herb Eclipta alba. Administration of EC was shown to have prominent anti‐adipogenic effects in 3T3‐L1 and hMSC derived adipocytes. It was shown to activate Wnt‐pathway and alter AKT signaling. Additionally, it caused cell cycle arrest and inhibited mitotic clonal expansion. EC treatment augmented mitochondrial biogenesis as well as function as estimated by expression of PGC1&agr;, UCP‐1, mitochondrial complexes and estimation of oxygen consumption rate. EC also reduced LPS‐induced inflammation and tunicamycin induced ER stress. Further, EC enhanced insulin sensitivity by increasing AKT phosphorylation, inhibiting PKC&agr;/&bgr;II phosphorylation and reducing leptin/adiponectin ratio. Finally, EC administration in Syrian golden hamsters was shown to have potent anti‐dyslipidemic effects. Cumulatively, encompassing pleiotropic activities of EC, it could prove to be a potential drug candidate against obesity, insulin resistance and related metabolic syndrome. Graphical abstract Figure. No Caption available. HighlightsEcliptal shows prominent anti‐adipogenic effects.Ecliptal blocked mitotic clonal expansion.Ecliptal treatment augmented mitochondrial functions.Ecliptal exhibited anti‐inflammatory and anti‐ER stress activities.In‐vivo, Ecliptal was shown to have anti‐dyslipidemic effects too.