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Type 2 diabetes mellitus (T2DM) is a metabolic disease characterized by reduced insulin sensitivity and dysfunction of β-cells. Although the increasing prevalence of diabetes worldwide is largely attributed to genetic predisposition or lifestyle factors (insufficient physical activity), and caloric intake. Environmental factors, exposure to xenobiotics and heavy metals have also been reported to be causative factors of T2DM. At this juncture, we, through our work unveil a plausible link between Pb2+ exposure and diabetes mellitus, and delineated a comprehensive understanding of the potential mechanisms of Pb2+-induced β-cells dysfunction. In our in vivo observations, we found that Pb2+ exposure strongly reduced glucose-stimulated insulin secretion and diminished functional pancreatic β-cell mass. Mechanistically, we found that Pb2+ downregulates intracellular cAMP level via hyper-activating Ca2+/calmodulin-dependent 3′,5′-cyclic nucleotide phosphodiesterase 1C and thereby reduces glucose-stimulated insulin secretion. Further, we report that Pb2+ inhibited mitochondrial adenosine triphosphate production and also identified Pb2+ as a negative regulator of β-cell proliferation via Ca2+/calmodulin-dependent protein kinase kinases-pAMPK-pRaptor axis. Together, our findings strongly reinforce Pb2+ to hijack the physiological role of calcium ions, by mimicking Ca2+ within pancreatic β-cell and thereby stands as a diabetogenic xenobiotic.

Nonalcoholic fatty liver disease (NAFLD) is an independent predictor of systemic insulin resistance and type 2 diabetes mellitus (T2DM). However, converse correlates between excess liver fat content and β-cell function remain equivocal. Specifically, how the accumulation of liver fat consequent to the enhanced de novo lipogenesis (DNL) leads to pancreatic β-cell failure and eventually to T2DM is elusive. Here we have identified low-molecular-weight calcium-binding protein S100A6 or calcyclin inhibits glucose-stimulated insulin secretion (GSIS) from β-cells through activation of the receptor for the advanced glycation end product (RAGE) and diminution of mitochondrial respiration. Serum S100A6 level is elevated both in human NAFLD patients and in a high-fat diet (HFD) induced mouse model of NAFLD. While serum S100A6 levels are negatively associated with β-cell insulin secretory capacity in human patients, depletion of hepatic S100A6 improves GSIS and glycemia in mice suggesting that S100A6 contributes to the pathophysiology of diabetes in NAFLD. Moreover, transcriptional induction of hepatic S100A6 is driven by the potent regulator of DNL, carbohydrate response element-binding protein (ChREBP), and ectopic expression of ChREBP in the liver suppresses GSIS in a S100A6 sensitive manner. Together, these data suggest elevated serum levels of S100A6 may serve as a biomarker in identifying NAFLD patients with a heightened risk of developing β-cell dysfunction. Overall, our data, implicate S100A6 as a hitherto unknown hepatokine to be activated by ChREBP and participates in the hepato-pancreatic communication to impair insulin secretion and drive the development of T2DM in NAFLD.

Nonalcoholic fatty liver disease (NAFLD) is an independent predictor of systemic insulin resistance and type 2 diabetes mellitus (T2DM). However, converse correlates between excess liver fat content and β-cell function remain equivocal. Specifically, how the accumulation of liver fat consequent to the enhanced de novo lipogenesis (DNL) leads to pancreatic β-cell failure and eventually to T2DM is elusive. Here, we have identified that low-molecular-weight calcium-binding protein S100A6, or calcyclin, inhibits glucose-stimulated insulin secretion (GSIS) from β cells through activation of the receptor for the advanced glycation end products and diminution of mitochondrial respiration. Serum S100A6 level is elevated both in human patients with NAFLD and in a high-fat diet–induced mouse model of NAFLD. Although serum S100A6 levels are negatively associated with β-cell insulin secretory capacity in human patients, depletion of hepatic S100A6 improves GSIS and glycemia in mice, suggesting that S100A6 contributes to the pathophysiology of diabetes in NAFLD. Moreover, transcriptional induction of hepatic S100A6 is driven by the potent regulator of DNL, carbohydrate response element-binding protein (ChREBP), and ectopic expression of ChREBP in the liver suppresses GSIS in a S100A6-sensitive manner. Together, these data suggest elevated serum levels of S100A6 may serve as a biomarker in identifying patients with NAFLD with a heightened risk of developing β-cell dysfunction. Overall, our data implicate S100A6 as, to our knowledge, a hitherto unknown hepatokine to be activated by ChREBP and that participates in the hepato-pancreatic communication to impair insulin secretion and drive the development of T2DM in NAFLD.

Type 2 diabetes mellitus (T2DM) is a metabolic disease characterized by reduced insulin sensitivity and dysfunction of β-cells. Although the increasing prevalence of diabetes worldwide is largely attributed to genetic predisposition or lifestyle factors (insufficient physical activity), and caloric intake. Environmental factors, exposure to xenobiotics and heavy metals have also been reported to be causative factors of T2DM. At this juncture, we, through our work unveil a plausible link between Pb(2+) exposure and diabetes mellitus, and delineated a comprehensive understanding of the potential mechanisms of Pb(2+)-induced β-cells dysfunction. In our in vivo observations, we found that Pb(2+) exposure strongly reduced glucose-stimulated insulin secretion and diminished functional pancreatic β-cell mass. Mechanistically, we found that Pb(2+) downregulates intracellular cAMP level via hyper-activating Ca(2+)/calmodulin-dependent 3′,5′-cyclic nucleotide phosphodiesterase 1C and thereby reduces glucose-stimulated insulin secretion. Further, we report that Pb(2+) inhibited mitochondrial adenosine triphosphate production and also identified Pb(2+) as a negative regulator of β-cell proliferation via Ca(2+)/calmodulin-dependent protein kinase kinases-pAMPK-pRaptor axis. Together, our findings strongly reinforce Pb(2+) to hijack the physiological role of calcium ions, by mimicking Ca(2+) within pancreatic β-cell and thereby stands as a diabetogenic xenobiotic.

Hierarchical nanostructures of anatase TiO2 with high active surface area has great significance in various applications. Here we have synthesized, highly photoactive hollow bowl like porous spheres of Titanium Dioxide (TiO2) (HBST) by a two-step synthesis procedure i.e. solvothermal strategy followed by thermal treatment. Solvothermally synthesized ultrathin nanoflakes TiO2 (7–8 nm thickness) was examined for the morphological and phase transformation using powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The nanoflakes, initially appeared to be assemble into a hierarchical nanostructure and finally converted to a compact spherical particle followed by hollow bowl like porous spheres of Titanium Dioxide (TiO2) (HBST) on heat treatment. Diffuse reflectance spectroscopy (DRS) measurement confirmed the band gap variation with respect to calcination conditions. Effect of obtained morphologies for photocatalytic and antibacterial activity was assessed using Bisphenol A (BPA) (a potent hazard, requiring immediate clearance) and E. coli (a potent microbial threat !!!). Both photocatalytic and antibacterial studies emphasized the conclusion, that hollow bowl morphology (HBST sample) is the best among all prepared morphologies. Mechanistic studies were carried out to reveal the role of photogenerated radicals and anions responsible for BPA degradation, where BPA degradation follow pseudo-first-order kinetics with rate constant value 0.00548 min−1. Results showed that HBST photocatalyst degraded nearly 89% of initial concentration of BPA in 360 min with high antibacterial efficiency towards E. coli on 1 h UV exposure. Reusability and repeatability tests were carried out to confirm the cyclic stability of the sample.

Dysregulated hepatic de novo lipogenesis contributes to the pathogenesis of nonalcoholic fatty liver disease in both humans and rodents. Clinical evidence suggests fatty liver to have a positive correlation with serum lead (Pb2+ ) levels. However, an exact mechanism of Pb2+ -induced fatty liver progression is still unknown. Here, we show that exposure to Pb2+ regulates ChREBP-dependent hepatic lipogenesis. Presence of Pb2+ ions within the hepatocytes reduces transcript and protein levels of sorcin, a cytosolic adaptor partner of ChREBP. Adenovirus-mediated overexpression of sorcin in Pb2+ exposed hepatocytes and an in vivo mouse model ameliorates liver steatosis and hepatotoxicity. Hereby, we present Pb2+ exposure to be a lethal disruptor of lipid metabolism in hepatocytes and highlight sorcin as a novel therapeutic target against Pb2+ -induced hepatic dyslipidemia.

Insulin resistance is thought to be a common link between obesity and Non-Alcoholic Fatty Liver Disease (NAFLD). NAFLD has now reached epidemic status worldwide and identification of molecules or pathways as newer therapeutic strategies either to prevent or overcome insulin resistance seems critical. Dysregulated hepatic lipogenesis (DNL) is a hallmark of NAFLD in humans and rodents. Therefore, reducing DNL accretion may be critical in the development of therapeutics of NAFLD. In our in vivo model (high-fat-diet fed [HFD] obese mice) we found Zinc oxide nanoparticles (ZnO NPs) significantly decreased HFD-induced hepatic steatosis and peripheral insulin resistance. This protective mechanism of ZnO NPs was signaled through hepatic SIRT1-LKB1-AMPK which restricted SREBP-1c within the cytosol limiting its transcriptional ability and thereby ameliorating HFD mediated DNL. These observations indicate that ZnO NP can serve as a therapeutic strategy to improve the physiological homeostasis during obesity and its associated metabolic abnormalities.

ChREBP is the master regulator of carbohydrate dependent glycolytic and lipogenic flux within metabolic tissues. It plays a vital role in hyper-calorific milieu by activating glycolysis, lipogenesis along with pentose phosphate shunt and glycogen synthesis, fostering immediate reduction in the systemic glycemic levels. Liver being the primary organ to sense disproportionate dietary intake and linked physiological stress, stimulates ChREBP to perform the aforementioned processes. Activated ChREBP also inhibits lipolysis and encourages proper disposal of excessive triglycerides into adipocytes from the liver ablating hepatic intracellular lipid trafficking. Chronic overeating or onset of positive energy balance, hyper-activates ChREBP and signals development, intensification of hepato-metabolic disorders, and allied discrepancies in the whole-body metabolic functioning. ChREBP thus gets negatively connotated as the primary regulator of hepatic disorders, owing to its inherent features as the primary glycemic sensor and the only transcription factor that can transduce glucose-dependent glycolytic and lipogenic signals. Through this review, we - try to recapitulate and emphasize on the sanative events coordinated by ChREBP in several pathophysiological states. In totality, we aim to uncouple the disease-causing aspects of ChREBP from its positive attributes evoked during a metabolic crisis, in hepato-metabolic diseases.

Development of a highly photostable, renal clearable, and nontoxic new NIR probe (CyG) for precise quantification of albumin in different biofluids and liver targeted in vivo albumin visualization is demonstrated. CyG’s inherent property to interact selectively with albumin among different biomolecules in intracellular environment with high degree of sensitivity helps CyG in targeted liver imaging. In addition to its long excitation/emission wavelengths (λex = 740 nm, λem = 804 nm), which are much above the biological tissue opaque window (400–700 nm) ensuring better photon penetration, diminished tissue autofluorescence and high contrasts, its molecular mass and size are far below the renal cutoff and hence, CyG qualifies as imaging material for clinical studies. We anticipate that CyG will provide new strategies to overcome the pitfall of present day albumin detection methods as well as accelerate the detection process at relatively lower costs without compromising the accuracy of detection. Moreover, t...

We demonstrate a strategy for the recognition of As5+ in aqueous solution using a red-emissive probe based on a perylene-Cu2+ ensemble decorated with peripheral free carboxyl functionality. Single crystal analysis helped us to understand the chemical structure of the probe. To the best of our knowledge, this is the first probe for arsenic detection which emits in the red region (λem = 600 nm). The perylene-Cu2+ ensemble exhibited a mega-Stokes shift (>100 nm) with a high degree of selectivity upon interaction with As5+, which indicated that the present probe has the potential to be used as a turn-on optical sensor for selective detection of As5+ with fewer experimental limitations. The detection limit was found to be 26 nM. Inspired by its good emissive properties, the ensemble was further explored for imaging As5+ in live cells. Because of its long-range emissive nature, no autofluorescence from the cellular species was observed during the imaging process. The probe was evaluated to be non-toxic and successfully permeated the cell membrane without the help of any permeabilizing agent to image As5+.

Dysregulated hepatic de novo lipogenesis contributes to the pathogenesis of nonalcoholic fatty liver disease in both humans and rodents. Clinical evidence suggests fatty liver to have a positive correlation with serum lead (Pb

Overconsumption of sucrose and other sugars has been associated with nonalcoholic fatty liver disease (NAFLD). Reports suggest hepatic de novo lipogenesis (DNL) as an important contributor to and regulator of carbohydrate-induced hepatic lipid accumulation in NAFLD. The mechanisms responsible for the increase in hepatic DNL due to overconsumption of carbohydrate diet are less than clear; however, literatures suggest high carbohydrate diet to activate the lipogenic transcription factor carbohydrate response element-binding protein (ChREBP), which further transcribes genes involved in DNL. Here, we provide an evidence of an unknown link between nuclear factor kappa-light chain enhancer of activated B cells (NF-κB) activation and increased DNL. Our data indicates high carbohydrate diet to enforce nuclear shuttling of hepatic NF-κB p65 and repress transcript levels of sorcin, a cytosolic interacting partner of ChREBP. Reduced sorcin levels, further prompted ChREBP nuclear translocation, leading to enhanced DNL and intrahepatic lipid accumulation both in vivo and in vitro. We further report that pharmacological inhibition of NF-κB abrogated high carbohydrate diet–mediated sorcin repression and thereby prevented ChREBP nuclear translocation and this, in turn, attenuated hepatic lipid accumulation both in in vitro and in vivo. Additionally, sorcin knockdown blunted the lipid-lowering ability of the NF-κB inhibitor in vitro. Together, these data suggest a heretofore unknown role for NF-κB in regulating ChREBP nuclear localization and activation, in response to high carbohydrate diet, for further explorations in lines of NAFLD therapeutics.