Inhibins are the major activin ligands expressed during early thymocyte development.
Activins are members of the transforming growth factor-beta (TGFbeta) superfamily, which regulate cell differentiation processes. Here we report the first quantitative analysis of the expression of Activin/Inhibin ligands, type I and II receptors, as well as Smad proteins in fetal (E14-E16) and adult thymic subpopulations. Our data showed that Alk4, ActRIIA, ActRIIB, and Smads 2, 3, and 4, are expressed in fetal thymus (E14 > E15 > E16) and in thymocytes from adult mice (mostly in the double negative [DN] subpopulation). Ligand expression analysis showed that betaA, betaB, and alpha subunits were mainly detected in thymic stromal cells. Interestingly, alpha subunits were expressed at much higher levels compared to betaA and betaB subunits, demonstrating for the first time the potential role of Inhibins as important mediators during early T cell development. Our data indicate that Activin/Inhibin signaling could regulate the process of thymus organogenesis and early thymocyte differentiation, as it has been demonstrated for other members of the TGF-beta superfamily.
Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Circuito Escolar s/n, México DF-04510.
Paula
P
Licona
Jesús
J
Chimal-Monroy
Gloria
G
Soldevila
D029404:Activin Receptors / Q000378:metabolism; D030201:Activin Receptors, Type I / Q000378:metabolism; D028341:Activins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015870:Gene Expression; D007150:Immunohistochemistry; D007265:Inhibins / Q000235:genetics / Q000378:metabolism*; D008024:Ligands; D051379:Mice; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D051901:Smad4 Protein / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000196:embryology*
D008024:Ligands; D051899:Smad2 Protein; C497783:Smad2 protein, mouse; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; D051901:Smad4 Protein; C490810:Smad4 protein, mouse; D028341:Activins; D007265:Inhibins; D029404:Activin Receptors; D030201:Activin Receptors, Type I; C498933:Acvr1b protein, mouse