Insufficient pancreatic β-cell mass or function results in diabetes mellitus. While significant progress has been made in regulating insulin secretion from β-cells in diabetic patients, no pharmacological agents have been described that increase β-cell replication in humans. Here we report aminopyrazine compounds that stimulate robust β-cell proliferation in adult primary islets, most likely as a result of combined inhibition of DYRK1A and GSK3B. Aminopyrazine-treated human islets retain functionality in vitro and after transplantation into diabetic mice. Oral dosing of these compounds in diabetic mice induces β-cell proliferation, increases β-cell mass and insulin content, and improves glycaemic control. Biochemical, genetic and cell biology data point to Dyrk1a as the key molecular target. This study supports the feasibility of treating diabetes with an oral therapy to restore β-cell mass, and highlights a tractable pathway for future drug discovery efforts.

The identification of factors that promote β cell proliferation could ultimately move type 1 diabetes treatment away from insulin injection therapy and toward a cure. We have performed high-throughput, cell-based screens using rodent β cell lines to identify molecules that induce proliferation of β cells. Herein we report the discovery and characterization of WS6, a novel small molecule that promotes β cell proliferation in rodent and human primary islets. In the RIP-DTA mouse model of β cell ablation, WS6 normalized blood glucose and induced concomitant increases in β cell proliferation and β cell number. Affinity pulldown and kinase profiling studies implicate Erb3 binding protein-1 and the IκB kinase pathway in the mechanism of action of WS6.

Autoimmune deficiency and destruction in either βcell mass or function can cause insufficient insulin levels and, as a result, hyperglycemia and diabetes. Thus, promoting β-cell proliferation could be one approach toward diabetes intervention. In this report we describe the discovery of a potent and selective DYRK1A inhibitor GNF2133, which was identified through optimization of a 6-azaindole screening hit. In vitro, GNF2133 is able to proliferate both rodent and human β-cells. In vivo, GNF2133 demonstrated significant dose-dependent glucose disposal capacity and insulin secretion in response to glucosepotentiated arginine-induced insulin secretion (GPAIS) challenge in rat insulin promoter and diphtheria toxin A (RIP-DTA) mice. The work described here provides new avenues to disease altering therapeutic interventions in the treatment of type 1 diabetes (T1D).

Several small molecule antagonists for Smoothened (Smo) have been developed, and achieved promising preclinical efficacy in cancers that are dependent on Hedgehog (Hh) signaling. However, in a recent clinical study, a drug-resistant D473H SMO mutant was identified that is thought to be responsible for cancer relapse in a patient with medulloblastoma. Here, we report two Smo antagonists that bind to distinct sites, as compared to known antagonists and agonists, and inhibit both wild-type and mutant Smo. These findings provide an insight of the ligand-binding sites of Smo and a basis for the development of potential therapeutics for tumors with drug-resistant Smo mutations.

The bird spider Ornithoctonus huwena Wang is a very venomous spider in China. Several compounds with different types of biological activities have been identified previously from the venom of this spider. In this study, we have performed a proteomic and peptidomic analysis of the venom. The venom was preseparated into two parts: the venom proteins with molecular weight (MW) higher than 10,000 and the venom peptides with MW lower than 10 000. Using one-dimensional gel electrophoresis (1-DE), two-dimensional gel electrophoresis (2-DE), and mass spectrometry, 90 proteins were identified, including some important enzymes, binding proteins, and some proteins with significant biological functions. For venom peptides, a combination of cation-exchange and reversed-phase chromatography was employed. More than 100 components were detected by mass spectrometry, and 47 peptides were sequenced by Edman degradation. The peptides display structural and pharmacological diversity and share little sequence similarity with peptides from other animal venoms, which indicates the venom of O. huwena Wang is unique. The venom peptides can be classified into several superfamilies. Also it is revealed that gene duplication and focal hypermutation have taken place during the evolution of the spider toxins.

BackgroundDiabetes mellitus is associated with many kinds of complications. Recent studies have shown that oxidative stress and inflammatory reactions have critical roles in the pathogenesis of diabetic gastroparesis. Curcumin is known to have antioxidant and anti-inflammatory properties. In the present study, we investigated the effect of curcumin on diabetic gastric motility in a Sprague Dawley rat model of type 1 diabetes mellitus.MethodsMale SD rats were divided into a control group, a control group receiving curcumin, a diabetic group, and a diabetic group receiving curcumin. Diabetes was induced by intraperitoneal injection of streptozotocin. Curcumin (150 mg/kg) was given intragastrically for 6 weeks, and blood glucose levels and body weights were measured. Stomachs were excised for analysis of gastric emptying rates, and levels of oxidative stress. NF-κB, I-κB, and stem cell factor (SCF)/c-kit protein levels were assessed by western blot analysis, while the apoptosis of interstitial cells of Cajal (ICCs) was assessed by TUNEL staining.ResultsCurcumin-treated diabetic rats showed significantly improved gastric emptying rates [(59.4 ± 7.5)%] compared with diabetic rats [(44.3 ± 5.7)%], as well as decreased levels of MDA [21.4 ± 1.8 (nmol/mg) vs 27.9 ± 2.1 (nmol/mg)], and increased SOD activity [126.2 ± 8.8 (units/mg) vs 107.9 ± 7.5 (units/mg)]. On the other hand, the gastric emptying level in the control group was not significantly different from that in the control group receiving curcumin treatment. In addition, curcumin-treated diabetic rats showed significantly increased levels of SCF/c-kit protein in stomach tissues, inhibited I-κB degradation and NF-κB activation, and reduced ICC apoptosis index [(26.2 ± 4.1)% vs (47.5 ± 6.2)%], compared with the diabetic group.ConclusionCurcumin treatment improved gastric emptying by blocking the production of oxidative stress, abolishing NF-κB signal transduction and enhancing expression of SCF/c-kit in rats with diabetic gastroparesis.

To investigate the heterogeneous protein composition of highly polarized hepatocyte plasma membrane (PM), three PM-associated subfractions were obtained from freshly isolated rat hepatocytes using density gradient centrifugation. The origins of the three subfractions were determined by morphological analysis and western blotting. The proteins were subjected to either one-dimensional (1-D) SDS-PAGE or two-dimensional (2-D) benzyldimethyl-n-hexadecylammonium chloride (BAC)/SDS-PAGE before nano-Liquid Chromatography-Electrospray Ionization--tandem mass spectrometry analysis (LC-ESI-MS/MS). A total of 613 non-redundant proteins were identified, among which 371 (60.5%) proteins were classified as PM or membrane-associated proteins according to GO annotations and the literatures and 32.4% had transmembrane domains. PM proteins from microsomal portion possessed the highest percentage of transmembrane domain, about 46.5% of them containing at least one transmembrane domain. In addition to proteins known to be located at polarized liver PM regions, such as asialoglycoprotein receptor 2, desmoplakin and bile salt export pump, several proteins which had the potential to become novel subfraction-specific proteins were also identified, such as annexin a6, pannexin and radixin. Our analysis also evaluated the application of 1-D SDS-PAGE and 2-D 16-BAC/SDS-PAGE on the separation of integral membrane proteins.

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