Hiroshi Takemitsu

Background: Mammalian sirtuins are homologs to the yeast silent information regulator 2 (Sir2), which is an NAD-dependent deacetylase. Sirtuins are comprised of 7 proteins, and each has different target proteins. Sirtuin 1 (SIRT1) plays important roles in maintaining metabolic functions and immune responses, and SIRT3 protects cells from oxidative stress-induced cell death. Both SIRT1 and SIRT3 are regulated by metabolic status and aging. Hence, SIRT1 and SIRT3 have been researched in metabolic diseases, such as type 2 diabetes mellitus (DM), fatty liver, and heart diseases. Although these diseases have been increasing, there is little information about relation between the diseases and SIRT1 and SIRT3 in cats. Therefore we cloned SIRT1 and SIRT3 cDNA, examined mRNA expression in cat tissues, and investigated the changes in SIRT1 and SIRT3 mRNA expression in peripheral blood leukocyte of cats fed on HFD for 6 weeks. Results: Cat SIRT1 and SIRT3 contained a catalytic core region and showed high sequence homology with other vertebrate SIRT1 (>61.3%) and SIRT3 (>65.9%) amino acids. Real-time polymerase chain reaction analyses revealed that high expression levels were observed in the liver and skeletal muscle for SIRT1 and in the heart for SIRT3 in cats. In addition, both cat SIRT1 and SIRT3 expression levels in the pancreas were different between individuals. Cat SIRT1 mRNA expression in peripheral blood leukocytes was significantly elevated in obese cats fed on HFD (P < 0.05). Conclusions: Cat SIRT1 and SIRT3 genes are highly conserved among vertebrates, and HFD feeding may be related to SIRT1 mRNA expression mechanisms in cat peripheral blood leukocytes.

Background: Bone marrow-derived mesenchymal stem cells (BM-MSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs) are potential cellular sources of therapeutic stem cells. MSCs are a multipotent population of cells capable of differentiating into a number of mesodermal lineages. Treatment using MSCs appears to be a helpful approach for structural restoration in regenerative medicine. Correct identification of these cells is necessary, but there is inadequate information on the MSC profile of cell surface markers and mRNA expression in dogs. In this study, we performed molecular characterization of canine BM-MSCs and AT-MSCs using immunological and mRNA expression analysis. Results: Samples were confirmed to be multipotent based on their osteogenic and adipogenic differentiation. And these cells were checked as stem cell, hematopoietic and embryonic stem cell (ESC) markers by flow cytometry. BM- and AT-MSCs showed high expression of CD29 and CD44, moderate expression of CD90, and were negative for CD34, CD45, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81. SSEA-1 was expressed at very low levels in AT-MSCs. Quantitative real-time PCR (qRT-PCR) revealed expression of Oct3/4, Sox2, and Nanog in BM- and AT-MSCs. There was no significant difference in expression of Oct3/4 and Sox2 between BM-MSCs and AT-MSCs. However, Nanog expression was 2.5-fold higher in AT-MSCs than in BM-MSCs. Using immunocytochemical analysis, Oct3/4 and Sox2 proteins were observed in BM- and AT-MSCs. Conclusion: Our results provide fundamental information to enable for more reproducible and reliable quality control in the identification of canine BM-MSCs and AT-MSCs by protein and mRNA expression analysis.