Tan JT, McLennan SV, Williams PF, Rezaeizadeh A, Lo LW, Bonner JG, Twigg SM. Connective tissue growth factor/CCN-2 is upregulated in epididymal and subcutaneous fat depots in a dietary-induced obesity model.

Neutrophils are important for wound repair, but their persistence can impair the healing process. Neutrophils express matrix metalloproteinases including MMP-9 and its regulator neutrophil gelatinase associated lipocalin (NGAL). Whether wounding affects neutrophil MMP-9 and NGAL in diabetic animals is not known. Skin wound tissue MMP-9 and NGAL was examined by qRT-PCR and immunohistochemistry in control, diabetic and insulin treated diabetic rats. The temporal expression of MMP-9 and NGAL mRNA, MMP-9 activity and the NGAL/MMP-9 complex was also investigated in an implant model and their circulating neutrophils. The cellular localisation of MMP-9 and NGAL was confirmed by immunofluorescence and the ability of glucose to regulate these factors was examined in isolated neutrophils. In skin wound tissue compared with control, diabetes increased neutrophil infiltration, NGAL mRNA and MMP-9 protein (P<0.05). Diabetes significantly increased implant neutrophil NGAL and MMP-9 protein as well as NGAL mRNA, wound fluid NGAL/MMP-9 complex and MMP-9 activity (all <0.05). Circulating neutrophil MMP-9 and NGAL was also increased in these diabetic animals (P<0.05). These changes were prevented by insulin treatment. Ex vivo, high glucose (25mM) increased neutrophil NGAL and MMP-9 (both by 2 fold, P<0.05). NGAL and MMP-9 are increased in wound and circulating neutrophils in diabetic rodents. These changes and the association between higher NGAL and increased wound fluid MMP-9 activity suggest that increased neutrophil NGAL may contribute to increased MMP-9 in poorly healing diabetic wounds. Whether targeting neutrophil NGAL or MMP-9 can improve diabetic wound healing remains to be investigated.

To alleviate adverse effects of heavy metal toxicity, diverse range of removing methods have been suggested, that is usage of algae, agricultural by-products and microorganisms. Here, we investigated lead (Pb) biosorption efficacy by two lactic acid bacteria species (LABs) in broiler chickens. In an in vitro study, Pb was added to culture medium of LABs (Lactobacillus pentosus ITA23 and Lactobacillus acidipiscis ITA44) in the form of lead acetate. Results showed that these LABs were able to absorb more than 90% of Pb from the culture medium. In follow-up in vivo study, LABs mixture was added to diet of broiler chickens contained lead acetate (200 mg/kg). Pb exposure significantly increased lipid peroxidation and decreased antioxidant activity in liver. The changes were recovered back to normal level upon LABs supplementation. Moreover, addition of LABs eliminated the liver tissue lesion and the suppressed performance in Pb-exposed chicks. Analysis of liver and serum samples indicated 48% and 28% reduction in Pb accumulation, respectively. In conclusion, results of this study showed that L. pentosus ITA23 and L. acidipiscis ITA44 effectively biosorb and expel dietary Pb from gastrointestinal tract of chickens.

Hyperglycemia in both type 1 and 2 diabetes is toxic to pancreatic beta cells and exacerbates the decline in functional beta cell mass in both diseases. Thus, identifying the molecular mechanism for how this glucotoxicity negatively impacts beta cells is essential for identifying new therapeutic targets to treat both forms of diabetes. We identified that EGF receptor feedback inhibitor Mig6 is induced in islets cultured in glucotoxic conditions and that Mig6 promotes apoptosis in beta cells. To define how the adaptor protein Mig6 promotes apoptosis, we sought to identify its interacting partners. Following immunoprecipitation of flag-tagged Mig6 in Ins1-derived 832/13 cells cultured in normal and toxic conditions, mass spectrometric analysis revealed protein phosphatase 2A (PP2A). PP2A controls many cellular functions ranging from metabolism, cell cycle, DNA replication, growth and apoptosis, and PP2A can be exploited by tumor cells to promote cell survival. Thus, we hypothesized Mig6 interacts with PP2A to regulate beta cell apoptosis. We cultured 832/13 cells and mouse islets in low (5 mM) or high glucose (HG, 20 mM) for up to 48h and validated that glucotoxicity increased methylation and decreased phosphorylation of PP2A (indicating activation). HG also increased expression of Mig6, CHOP (ER stress), γH2AX (DNA damage response), and cleaved caspase 3 (CC3; apoptosis). Compared to controls, siRNA-mediated suppression of Mig6 in 832/13 cells increased methylated PP2A and decreased γH2AX and CC3, suggesting Mig6 antagonizes beta cell survival. We generated mice lacking Mig6 in beta cells (Mig6βKO) by crossing Mig6-floxed mice (Mig6fl/fl) with RIP-Cre mice. Beta cell mass and glucose homeostasis were similar between Mig6βKO and control Mig6fl/fl littermates. Islets from Mig6βKO mice had increased methylated PP2A during HG compared to controls. We speculate the Mig6-PP2A interaction limits PP2A activation; hence, disrupting Mig6-PP2A or inhibiting Mig6 could promote compensatory beta cell survival by activating PP2A. Disclosure A. Rezaeizadeh: None. B.M. Bauer: None. P.T. Fueger: None.