Abstract

Suppressor of mek1 (Dictyostelium) homolog 2 (Smek2), was identified as one of the responsible genes for diet-induced hypercholesterolemia (DIHC) of exogenously hypercholesterolemic (ExHC) rats. A deletion mutation in Smek2 leads to DIHC via impaired glycolysis in the livers of ExHC rats. The intracellular role of Smek2 remains obscure. We used microarrays to investigate Smek2 functions with ExHC and ExHC.BN-Dihc2BN congenic rats that harbor a non-pathological Smek2 allele from Brown-Norway rats on an ExHC background. Microarray analysis revealed that Smek2 dysfunction leads to extremely low sarcosine dehydrogenase (Sardh) expression in the liver of ExHC rats. Sarcosine dehydrogenase demethylates sarcosine, a byproduct of homocysteine metabolism. The ExHC rats with dysfunctional Sardh developed hypersarcosinemia and homocysteinemia, a risk factor for atherosclerosis, with or without dietary cholesterol. The mRNA expression of Bhmt, a homocysteine metabolic enzyme and the hepatic content of betaine (trimethylglycine), a methyl donor for homocysteine methylation were low in ExHC rats. Results suggest that homocysteine metabolism rendered fragile by a shortage of betaine results in homocysteinemia, and that Smek2 dysfunction causes abnormalities in sarcosine and homocysteine metabolism.

Details

Title
Mutation in Smek2 regulating hepatic glucose metabolism causes hypersarcosinemia and hyperhomocysteinemia in rats
Author
Tanaka, Yasutake 1 ; Kawano, Michio 1 ; Nakashima, Sawako 1 ; Yamaguchi, Chisato 1 ; Asahina, Makoto 1 ; Sakamoto, Mai 1 ; Shirouchi, Bungo 1 ; Tashiro, Kousuke 2 ; Imaizumi, Katsumi 1 ; Sato, Masao 3 

 Kyushu University, Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Fukuoka, Japan (GRID:grid.177174.3) (ISNI:0000 0001 2242 4849) 
 Kyushu University, Laboratory of Molecular Gene Technics, Department of Genetic Resources Technology, Faculty of Agriculture, Fukuoka, Japan (GRID:grid.177174.3) (ISNI:0000 0001 2242 4849) 
 Kyushu University, Laboratory of Nutrition Chemistry, Division of Bioresource and Bioenvironmental Sciences, Graduate School, Fukuoka, Japan (GRID:grid.177174.3) (ISNI:0000 0001 2242 4849); Kyushu University, Laboratory of Nutrition Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Fukuoka, Japan (GRID:grid.177174.3) (ISNI:0000 0001 2242 4849) 
Pages
3053
Publication year
2023
Publication date
2023
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2778491852
Copyright
© The Author(s) 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.