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Gene transfer of active Akt1 by an infectivity-enhanced adenovirus impacts ?-cell survival and proliferation differentially in vitro and in vivo.

ABSTRACT: Type 1 Diabetes is characterized by an absolute insulin deficiency due to the autoimmune destruction of insulin producing ?-cells in the pancreatic islets. Akt1/Protein Kinase B is the direct downstream target of PI3 Kinase activation, and has shown potent anti-apoptotic and proliferation-inducing activities. This study was designed to explore whether gene transfer of constitutively active Akt1 (CA-Akt1) would promote ?-cell survival and proliferation, thus be protective against experimental diabetes. In the study, a fiber-modified infectivity-enhanced adenoviral vector, Ad5RGDpK7, was used to deliver rat insulin promoter (RIP)-driven CA-Akt1 into ?-cells. Our data showed this vector efficiently delivered CA-Akt1 into freshly isolated pancreatic islets, and promoted islet cell survival and ?-cell proliferation in vitro. The therapeutic effect of the vector in vivo was assessed using streptozotocin (STZ)-induced diabetes mice. Two means of vector administration were explored: intravenous and intra-bile ductal injections. While direct vector administration into pancreas via bile-ductal injection resulted in local adverse effect, intravenous injection of the vectors offered therapeutic benefits. Further analysis suggests systemic vector administration caused endogenous Akt expression and activation in islets, which may be responsible, at least in part, for the protective effect of the infectivity-enhanced CA-Akt1 gene delivery vector. Taken together, our data suggest CA-Akt1 is effective in promoting ?-cell survival and proliferation in vitro, but direct in vivo use is compromised by the efficacy of transgene delivery into ?-cells. Nonetheless, the vector evoked the expression and activation of endogenous Akt in the islets, thus offering beneficial bystander effect against STZ-induced diabetes.

SUBMITTER: Bone RN

PROVIDER: S-EPMC3605165 | biostudies-other | 2012 Nov-Dec

REPOSITORIES: biostudies-other

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Gene transfer of active Akt1 by an infectivity-enhanced adenovirus impacts β-cell survival and proliferation differentially in vitro and in vivo.

Bone Robert N RN Icyuz Mert M Zhang Yanqing Y Zhang Yuan Y Cui Wanxing W Wang Hongjun H Peng Ji-Bin JB Matthews Qiana L QL Siegal Gene P GP Wu Hongju H

Islets 20121101 6

Type 1 Diabetes is characterized by an absolute insulin deficiency due to the autoimmune destruction of insulin producing β-cells in the pancreatic islets. Akt1/Protein Kinase B is the direct downstream target of PI3 Kinase activation, and has shown potent anti-apoptotic and proliferation-inducing activities. This study was designed to explore whether gene transfer of constitutively active Akt1 (CA-Akt1) would promote β-cell survival and proliferation, thus be protective against experimental dia ...[more]

PMID: 23183538

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Project description:BackgroundHIV eradication strategies are now being evaluated in vitro and in vivo. A cornerstone of such approaches is maximal suppression of viral replication with combination antiretroviral therapy (ART). Since many antiretroviral agents have off target effects, and different classes target different components of the viral life cycle, we questioned whether different classes of ART might differentially affect the survival and persistence of productively HIV-infected CD4 T cells.MethodsIn vitro infections of primary CD4 T cells using clinical isolates of HIV-1 that were either protease inhibitor susceptible (HIV PI-S), or resistant (HIV PI-R) were treated with nothing, lopinavir, efavirenz or raltegravir. Cell viability, apoptosis, and the proportion of surviving cells that were P24 positive was assessed by flow cytometry.ResultsIn HIV PI-S infected primary cultures, all three antiretroviral agents decreased viral replication, and reduced the total number of cells that were undergoing apoptosis (P?<?0.01) similarly. Similarly, in the HIV PI-R infected cultures, both efavirenz and raltegravir reduced viral replication and reduced apoptosis compared to untreated control (P?<?0.01), while lopinavir did not, suggesting that HIV replication drives T cell apoptosis, which was confirmed by association by linear regression (P?<?0.0001) . However since HIV protease has been suggested to directly induce apoptosis of infected CD4 T cells, and HIV PI are intrinsically antiapoptotic, we evaluated apoptosis in productively infected (HIV P24+) cells. More HIV p24 positive cells were apoptotic in the Efavirenz or raltegravir treated cultures than the lopinavir treated cultures (P?=?0.0008 for HIV PI-R and P?=?0.06 for the HIV PI-S), indicating that drug class impacts survival of productively infected CD4 T cells.ConclusionsInhibiting HIV replication with a PI, NNRTI or INSTI reduces total HIV-induced T cell apoptosis. However, blocking HIV replication with PI but not with NNRTI or INSTI promotes survival of productively HIV-infected cells. Thus, selection of antiretroviral agents may impact the success of HIV eradication strategies.

Project description:BackgroundHIV eradication strategies are now being evaluated in vitro and in vivo. A cornerstone of such approaches is maximal suppression of viral replication with combination antiretroviral therapy (ART). Since many antiretroviral agents have off target effects, and different classes target different components of the viral life cycle, we questioned whether different classes of ART might differentially affect the survival and persistence of productively HIV-infected CD4 T cells.MethodsIn vitro infections of primary CD4 T cells using clinical isolates of HIV-1 that were either protease inhibitor susceptible (HIV PI-S), or resistant (HIV PI-R) were treated with nothing, lopinavir, efavirenz or raltegravir. Cell viability, apoptosis, and the proportion of surviving cells that were P24 positive was assessed by flow cytometry.ResultsIn HIV PI-S infected primary cultures, all three antiretroviral agents decreased viral replication, and reduced the total number of cells that were undergoing apoptosis (P < 0.01) similarly. Similarly, in the HIV PI-R infected cultures, both efavirenz and raltegravir reduced viral replication and reduced apoptosis compared to untreated control (P < 0.01), while lopinavir did not, suggesting that HIV replication drives T cell apoptosis, which was confirmed by association by linear regression (P < 0.0001) . However since HIV protease has been suggested to directly induce apoptosis of infected CD4 T cells, and HIV PI are intrinsically antiapoptotic, we evaluated apoptosis in productively infected (HIV P24+) cells. More HIV p24 positive cells were apoptotic in the Efavirenz or raltegravir treated cultures than the lopinavir treated cultures (P = 0.0008 for HIV PI-R and P = 0.06 for the HIV PI-S), indicating that drug class impacts survival of productively infected CD4 T cells.ConclusionsInhibiting HIV replication with a PI, NNRTI or INSTI reduces total HIV-induced T cell apoptosis. However, blocking HIV replication with PI but not with NNRTI or INSTI promotes survival of productively HIV-infected cells. Thus, selection of antiretroviral agents may impact the success of HIV eradication strategies.

Dataset Information

Gene transfer of active Akt1 by an infectivity-enhanced adenovirus impacts ?-cell survival and proliferation differentially in vitro and in vivo.

Publications

Gene transfer of active Akt1 by an infectivity-enhanced adenovirus impacts β-cell survival and proliferation differentially in vitro and in vivo.

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