Functional interaction between TRPC1 channel and connexin-43 protein: a novel pathway underlying S1P action on skeletal myogenesis.
We recently demonstrated that skeletal muscle differentiation induced by sphingosine 1-phosphate (S1P) requires gap junctions and transient receptor potential canonical 1 (TRPC1) channels. Here, we searched for the signaling pathway linking the channel activity with Cx43 expression/function, investigating the involvement of the Ca(2+)-sensitive protease, m-calpain, and its targets in S1P-induced C2C12 myoblast differentiation. Gene silencing and pharmacological inhibition of TRPC1 significantly reduced Cx43 up-regulation and Cx43/cytoskeletal interaction elicited by S1P. TRPC1-dependent functions were also required for the transient increase of m-calpain activity/expression and the subsequent decrease of PKCα levels. Remarkably, Cx43 expression in S1P-treated myoblasts was reduced by m-calpain-siRNA and enhanced by pharmacological inhibition of classical PKCs, stressing the relevance for calpain/PKCα axis in Cx43 protein remodeling. The contribution of this pathway in myogenesis was also investigated. In conclusion, these findings provide novel mechanisms by which S1P regulates myoblast differentiation and offer interesting therapeutic options to improve skeletal muscle regeneration.
Meacci
Elisabetta
E
Department of Biochemical Sciences, University of Florence, Viale GB Morgagni 50, 50134, Florence, Italy. elisabetta.meacci@unifi.it
Bini
Francesca
F
Sassoli
Chiara
C
Martinesi
Maria
M
Squecco
Roberta
R
Chellini
Flaminia
F
Zecchi-Orlandini
Sandra
S
Francini
Fabio
F
Formigli
Lucia
L
D000818:Animals; D002154:Calpain / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D018031:Connexin 43 / Q000235:genetics / Q000378:metabolism*; D008246:Lysophospholipids / Q000378:metabolism*; D051379:Mice; D024510:Muscle Development / Q000502:physiology*; D018482:Muscle, Skeletal / Q000196:embryology* / Q000254:growth & development* / Q000378:metabolism; D032448:Myoblasts, Skeletal / Q000166:cytology / Q000502:physiology; D018408:Patch-Clamp Techniques; D051571:Protein Kinase C-alpha / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*
D018031:Connexin 43; D008246:Lysophospholipids; D034741:RNA, Small Interfering; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; C060506:sphingosine 1-phosphate; D051571:Protein Kinase C-alpha; D002154:Calpain; C449000:m-calpain; D013110:Sphingosine