title: NFAT isoforms regulate muscle fiber type transition without altering CaN during aerobic training.
abstract: The purpose of this study was to determine whether the aerobic training-induced fiber-type transition in different muscles is associated with alterations in NFAT isoforms gene expression. We hypothesized that the aerobic training-induced fiber-type transition would be mediated by NFATc1-c3 isoforms without altering the CaN expression. Male Wistar rats (80 days old) were divided into a trained group (T; n=8) that underwent an 8-wk swimming endurance training program (5 days/week) and a control group (C; n=8). After the experimental period, the animals were sacrificed, and the soleus (SOL) and plantaris (PL) muscles were collected for morphometrical, histochemical and molecular analyses. Aerobic training induced a type I-to-type IIA fiber transition in the SOL muscle and a type IIB-to-type IIA fiber transition in the PL muscle, which were concomitant with a significant (p<0.05) increase in NFATc1-c3 gene expression in both the SOL and PL muscles. In contrast, the expression levels of calcineurin (CaN) and NFATc4 remained unchanged. Therefore, our results showed that fiber type switching induced by aerobic training is mediated by NFATc1-c3 isoforms without altering the CaN expression.
authors.affiliation: Morphology, São Paulo State University (UNESP), Botucatu, Brazil.
authors.forename: I J
authors.initials: IJ
authors.lastname: Vechetti
authors.forename: A F
authors.initials: AF
authors.lastname: Aguiar
authors.forename: R W A
authors.initials: RW
authors.lastname: de Souza
authors.forename: F L A
authors.initials: FL
authors.lastname: Almeida
authors.forename: H B
authors.initials: HB
authors.lastname: de Almeida Dias
authors.forename: M A
authors.initials: MA
authors.lastname: de Aguiar Silva
authors.forename: F R
authors.initials: FR
authors.lastname: Carani
authors.forename: R L P
authors.initials: RL
authors.lastname: Ferraresso
authors.forename: R F
authors.initials: RF
authors.lastname: Carvalho
authors.forename: M
authors.initials: M
authors.lastname: Dal-Pai-Silva
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D019703:Calcineurin / Q000378:metabolism*; D008297:Male; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism*; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000378:metabolism*; D010807:Physical Endurance / Q000502:physiology; D020033:Protein Isoforms / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013550:Swimming / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D015415:Biomarkers; D050778:NFATC Transcription Factors; C584440:NFATC1 protein, rat; D020033:Protein Isoforms; D014157:Transcription Factors; D019703:Calcineurin; D018995:Myosin Heavy Chains