Expression Analysis of Senescence-Associated Genes: Their Possible Involvement in Diabetes

Abstract

Accumulation of errors and damages concomitant with aging would cause not only physiologic dysfunction but also diseases such as cancer, diabetes and hypertension. In this study, we tried to clarify factors involved in senescence programs by proteomics approach, and assumed their involvements in the aging-associated diseases. In the present study, we used human diploid fibroblast cells (TIG-1) as model cell lines. Replicative senescence was induced in TIG-1 cells by serial passagings. Membrane proteins were prepared by Cell Surface Protein Isolation Kit and were subjected to 1D and 2D SDS-PAGE and subsequent silver staining. Proteins whose expressions were changed between young and old TIG-1 cells were identified by subjecting them to MALDI TOF-MS analysis. Then, we identified 16 candidates for senescence-associated gene. Next, we investigated the expression profiles of these genes in replicative senescence by quantitative real-time PCR. Consequently, 14 genes were identified as senescence-associated genes. Next, we investigated the involvement of these genes in the onset of diabetes that is known to be one of aging-related diseases by using cDNA derived from muscle and pancreas tissue of diabetes patients in quantitative real-time PCR. Among these 14 senescence-associated genes, expressions of 13–14 genes were augmented in muscle and/or pancreas tissues of diabetes patients.