title: The activity of calpains in lymphocytes is glucose-dependent and is decreased in diabetic patients.
abstract: Calpains are nonlysosomal calcium-dependent cysteine proteases that participate in insulin secretion and action. Polymorphisms in the calpain-10 gene have been shown to increase the risk for type 2 diabetes. Since white blood cells have been used to study glucose homeostasis, the present study was carried to find out if calpains have different activity and/or expression in accessible cells such as lymphocytes of individuals with or without type 2 diabetes. Fasting blood glucose concentration was significantly higher in diabetic subjects, whereas the difference in the activity of calpains evaluated in basal and stimulating extracellular glucose concentration was significantly higher in the lymphocytes from the control group. The mRNA expression of calpain-10 was similar in the lymphocytes of both patients and controls. The protein blots showed four bands that ranged between 75 and 50 kDa; however, no statistical differences were observed in the expression of the calpain-10 isoforms between controls and patients. Data obtained showed that human lymphocytes express calpain-10 mRNA and protein, showing a similar expression between diabetic and control subjects, nevertheless in the diabetic group calpain activity was less glucose-sensitive.
authors.affiliation: Department of Genomic Medicine and Environmental Toxicology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico.
authors.forename: Andrea
authors.initials: A
authors.lastname: Díaz-Villaseñor
authors.forename: Marcia
authors.initials: M
authors.lastname: Hiriart
authors.forename: Mariano E
authors.initials: ME
authors.lastname: Cebrián
authors.forename: Rogelio
authors.initials: R
authors.lastname: Zacarías-Castillo
authors.forename: Patricia
authors.initials: P
authors.lastname: Ostrosky-Wegman
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D002154:Calpain / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D020033:Protein Isoforms; D012333:RNA, Messenger; D002154:Calpain; C415197:calpain 10