Excessive intake of alcohol increases blood ethanol concentration and induces brain developmental disorders manifested as fetal alcohol syndrome (FAS). Children born with FAS have abnormal facial features with mild to sever mental retardation. Cerebellum is one of the most sensitive areas in the brain that is affected by ethanol. However, mechanisms underlying the deleterious effects of ethanol in cerebellum are largely unknown. Our preliminary studies demonstrated that moderate dose of ethanol (blood ethanol concentration of 40 mM) inhibits differentiation, and high dose of ethanol (blood ethanol concentration 80 mM) induces apoptosis in cerebellar granular neurons (CGNs) under in vivo conditions. But under in vitro conditions, higher concentration of ethanol is required for producing similar results, suggesting that some other factor(s) might also be involved. It was further observed that under in vitro conditions ethanol (40 mM and 80 mM) in the presence of physiological concentration of retinoic acid (100 nM) had similar deleterious effects as observed under in vivo conditions. Based on these studies, it is our working hypothesis that harmful effects of ethanol on differentiation and survival of CGNs are mediated by retinoic acid. To test this hypothesis we will determine whether (1) ethanol exposure in vivo affects activation of retinoic acid receptors and (2) whether administration of retinoic acid receptor antagonists protect against harmful effects of ethanol on differentiation and survival of CGNs. To address the issue, rat pups (postnatal day 7) which are widely used as a rodent model of fetal alcohol syndrome, will be exposed to ethanol. Cerebellar granular neurons will be isolated and used for the proposed studies. The transcriptional activities of retinoic acid receptors will be studied by electromobility shift assay. If ethanol interferes in transcriptional activities, it will suggest that retinoic acid receptors might be mediating ethanol effects. Our studies demonstrated that Rho GTPases play a crucial role in differentiation of CGNs; and, exposure of ethanol in vivo affected the activation of these GTPases. It is plausible that impaired activation of receptors affects Rho GTPase signaling. To test this possibility retinoic acid receptor antagonists, known to prevent the activation, will be used. Studies will determine whether antagonists prevent the effects of ethanol on activation of Rho GTPases and protect CGNs against harmful effects of ethanol. To study the role of Rho GTPases we will use in vitro cell culture model. In this cell culture model CGNs will be exposed to ethanol (40 mM, 80 mM) in the presence of retinoic acid (100 nM). Whether, expression of constitutively active or dominant negative forms of Rho GTPases prevent toxic effects of ethanol on differentiation and survival of CGNs will be investigated. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AA016121-01A2
Application #
7305494
Study Section
Health Services Research Review Subcommittee (AA)
Program Officer
Noronha, Antonio
Project Start
2008-07-01
Project End
2010-06-30
Budget Start
2008-07-01
Budget End
2009-06-30
Support Year
1
Fiscal Year
2008
Total Cost
$168,625
Indirect Cost
Name
University of South Carolina at Columbia
Department
Pathology
Type
Schools of Medicine
DUNS #
041387846
City
Columbia
State
SC
Country
United States
Zip Code
29208
Kumar, Ambrish; Hu, Jianjun; LaVoie, Holly A et al. (2014) Conformational changes and translocation of tissue-transglutaminase to the plasma membranes: role in cancer cell migration. BMC Cancer 14:256
Kumar, Ambrish; Fan, Daping; Dipette, Donald J et al. (2014) Sparstolonin B, a novel plant derived compound, arrests cell cycle and induces apoptosis in N-myc amplified and N-myc nonamplified neuroblastoma cells. PLoS One 9:e96343
Kumar, Ambrish; Al-Sammarraie, Nadia; DiPette, Donald J et al. (2014) Metformin impairs Rho GTPase signaling to induce apoptosis in neuroblastoma cells and inhibits growth of tumors in the xenograft mouse model of neuroblastoma. Oncotarget 5:11709-22
Singh, Chandra K; Kumar, Ambrish; Lavoie, Holly A et al. (2013) Diabetic complications in pregnancy: is resveratrol a solution? Exp Biol Med (Maywood) 238:482-90
Singh, Chandra K; Kumar, Ambrish; LaVoie, Holly A et al. (2012) Resveratrol prevents impairment in activation of retinoic acid receptors and MAP kinases in the embryos of a rodent model of diabetic embryopathy. Reprod Sci 19:949-61
Kumar, Ambrish; Singh, Chandra K; Lavoie, Holly A et al. (2011) Resveratrol restores Nrf2 level and prevents ethanol-induced toxic effects in the cerebellum of a rodent model of fetal alcohol spectrum disorders. Mol Pharmacol 80:446-57
Singh, Chandra K; Kumar, Ambrish; Hitchcock, David B et al. (2011) Resveratrol prevents embryonic oxidative stress and apoptosis associated with diabetic embryopathy and improves glucose and lipid profile of diabetic dam. Mol Nutr Food Res 55:1186-96
Kumar, Ambrish; Singh, Chandra K; DiPette, Donald D et al. (2010) Ethanol impairs activation of retinoic acid receptors in cerebellar granule cells in a rodent model of fetal alcohol spectrum disorders. Alcohol Clin Exp Res 34:928-37