Altered gene expression profiles in the hippocampus and prefrontal cortex of type 2 diabetic rats

ABSTRACT: There has been an incresing body of epidemiologic and biochemical evidence implying the role of cerebral insulin resistance in Alzheimer-type dementia. For a better understanding of the insulin effect on the central nervous system we performed microarray-based gene expression profiling in the hippocampus, striatum and prefrontal cortex of streptozotocin-induced and spontaneously diabetic Goto-Kakizaki rats as model animals for type 1 and type 2 diabetes, respectively. Following pathway analysis and validation of gene lists by RT-PCR, 30 genes from hippocampus, such as the inhibitory neuropeptide galanin, synuclein gamma and uncoupling protein 2, and 22 genes from the prefrontal cortex, e.g. galanin receptor 2, protein kinase gamma and epsilon, ABCA1, CD47 and the RET protooncogene, were found to exhibit altered expression levels in type 2 diabetic model animals in comparison to non-diabetic control animals. These gene lists proved to be partly overlapping and encompassed genes related to neurotransmission, lipidmetabolism, neuronal development, insulin secretion, oxidative damage and DNA repair. On the other hand, no significant alterations were found in the transcriptomes of the corpus sriatum in the same animals. Changes in the cerebral gene expression profiles seemed to be specific for the type 2 diabetic model, as no such alterations were found in streptozotocin-treated animals. According to our knowledge this is the first characterization of the whole-genome expression changes of specific brain regions in a diabetic model. Our findings shed light on the complex role of insulin signaling in fine-tuning brain functions, and provide further experimental evidence in support of the recently elaborated theory of type 3diabetes. Experiments were performed with 9 animals from each group. Wistar rats (control), streptoztocin-treated Wistar rats (type 1 diabetes) and Goto-Kakizaki rats (type 2 diabetes). The brain was removed and the striatum, hippocampus and prefrontal cortex were dissected. Samples from 3-3 identically treated animals were pooled. That means, 3 biological parallels were prepared from each brain region of type 1 or type 2 diabetic and control animals, amounting to a total of 27 different pooled samples.

ORGANISM(S): Rattus norvegicus

SUBMITTER: Omar Abdul-Rahman 

PROVIDER: E-GEOD-34451 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress