NAD+ supplementation reverses the oxidative stress induced PARP1 signalling in D. discoideum

Increased oxidative stress leads to cell death by inducing DNA damage, PARP activation and energy depletion in age related disorders which are a growing concern due to increased life expectancy. Indeed, cellular NAD+ levels, depletion of which is one of the consequences of overactive PARP, also decline with age. We previously showed rescue in oxidative stress induced paraptotic and necrotic cell death by PARP1 inhibition in D. discoideum. Inhibition of PARP1 activity prevented cellular depletion of its substrate NAD+. To understand the significance of NAD+ depletion in PARP1 mediated oxidative stress induced cell death, exogenous addition of NAD+ was done. Addition of NAD+ prevented PARP1 mediated oxidative stress induced cell death at low doses upto 10 mM NAD+, nevertheless led to an anticipated increase in PARP1 activity. NAD+ significantly prevented oxidative stress induced cell death in D. discoideum. Exogenous NAD+ averted depletion of cellular NAD+ and mitochondrial membrane potential changes that were triggered by oxidative stress, without getting affected by the elevated ROS levels. Altogether, this study ascertains that NAD+ replenishment overcomes cadmium or H2O2 induced cell death by preventing cellular energy collapse incited by PARP1 activation. Thus, our results explicitly demonstrate that PARP1 overactivation led NAD+ depletion but not PARP1 activity per se is of consequential significance in causing oxidative stress induced D. discoideum cell death. Moreover, NAD+ supplementation could be a beneficial approach in aging and age-related disorders mediated by PARP

Oreocnide integrifolia Flavonoids Augment Reprogramming for Islet Neogenesis and β-Cell Regeneration in Pancreatectomized BALB/c Mice

Agents which can either trigger proliferation of β-cells or induce neogenesis of β-cells from precursors would be of pivotal role in reversing diabetic manifestations. We examined the role of flavonoid rich fraction (FRF) of Oreocnide integrifolia leaves using a mice model of experimental regeneration. BALB/c mice were subjected to ~70% pancreatectomy (Px) and supplemented with FRF for 7, 14, and 21 days after pancreatectomy. Px animals displayed increased blood glucose levels and decreased insulin titres which were ameliorated by FRF supplementation. FRF-treated mice demonstrated prominent newly formed islets budding off from ducts and depicting increased BrdU incorporation. Additionally, transcripts levels of Ins1/2, Reg-3α/γ, Ngn-3, and Pdx-1 were upregulated during the initial 1 week. The present study provides evidence of a nutraceutical contributing to islet neogenesis from ductal cells as the mode of β-cell regeneration and a potential therapeutic for clinical trials in management of diabetic manifestations

Antioxidant rich flavonoids from Oreocnide integrifolia enhance glucose uptake and insulin secretion and protects pancreatic β-cells from streptozotocin insult

<p>Abstract</p> <p>Background</p> <p>Insulin deficiency is the prime basis of all diabetic manifestations and agents that can bring about insulin secretion would be of pivotal significance for cure of diabetes. To test this hypothesis, we carried out bioactivity guided fractionation of <it>Oreocnide integrifolia </it>(Urticaceae); a folklore plant consumed for ameliorating diabetic symptoms using experimental models.</p> <p>Methods</p> <p>We carried out bioassay guided fractionation using RINmF and C2C12 cell line for glucose stimulated insulin secretion (GSIS) and glucose uptake potential of fractions. Further, the bioactive fraction was challenged for its GSIS in cultured mouse islets with basal (4.5 mM) and stimulated (16.7 mM) levels of glucose concentrations. The Flavonoid rich fraction (FRF) was exposed to 2 mM streptozotocin stress and the anti-ROS/RNS potential was evaluated. Additionally, the bioactive fraction was assessed for its antidiabetic and anti-apoptotic property <it>in-vivo </it>using multidose streptozotocin induced diabetes in BALB/c mice.</p> <p>Results</p> <p>The results suggested FRF to be the most active fraction as assessed by GSIS in RINm5F cells and its ability for glucose uptake in C2C12 cells. FRF displayed significant potential in terms of increasing intracellular calcium and cAMP levels even in presence of a phosphodiesterase inhibitor, IBMX in cultured pancreatic islets. FRF depicted a dose-dependent reversal of all the cytotoxic manifestations except peroxynitrite and NO formation when subjected <it>in-vitro </it>along with STZ. Further scrutinization of FRF for its <it>in-vivo </it>antidiabetic property demonstrated improved glycemic indices and decreased pancreatic β-cell apoptosis.</p> <p>Conclusions</p> <p>Overall, the flavonoid mixture has shown to have significant insulin secretogogue, insulinomimetic and cytoprotective effects and can be evaluated for clinical trials as a therapeutant in the management of diabetic manifestations.</p

<span style="font-size:11.0pt;font-family: "Times New Roman","serif";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Staurosporine induced poly (ADP-ribose) polymerase independent cell death in <i style="mso-bidi-font-style:normal">Dictyostelium discoideum</i></span>

80-86In the present study <i style="mso-bidi-font-style: normal">D. discoideum has been used as a model organism to understand the role of poly (ADP-ribose) polymerase (PARP) in caspase independent paraptotic cell death pathways. D. discoideum lacks caspases and Bcl-2 family proteins; nevertheless it has 9 potential genes for PARP. PARP has been known to get activated in various cell death associated diseases. In this study kinetics of cell death induced by staurosporine (STS), a bacterial alkaloid, was established to unravel the role of PARP. It was found that STS induced cell death in D. discoideum did not involve PARP activation, however it involved cathepsin D. Results indicated that an alternative mechanism may be existing in D. discoideum that<i style="mso-bidi-font-style: normal"> lacks Bcl-2 family proteins for STS induced cell death that evades Bax involvement