Type VIII collagen modulates TGF-ß1-induced proliferation of mesangial cells.
J Am Soc Nephrol
; 22(4): 649-63, 2011 Apr.
Article
en En
| MEDLINE
| ID: mdl-21372207
ABSTRACT
Mesangial cells in diabetic mice and human kidneys with diabetic nephropathy exhibit increased type VIII collagen, a nonfibrillar protein that exists as a heterodimer composed of α1(VIII) and α2(VIII), encoded by Col8a1 and Col8a2, respectively. Because TGF-ß1 promotes the development of diabetic glomerulosclerosis, we studied whether type VIII collagen modulates the effects of TGF-ß1 in mesangial cells. We obtained primary cultures of mesangial cells from wild-type, doubly heterozygous (Col8a1(+/-)/Col8a2(+/-)), and double-knockout (Col8a1(-/-)/Col8a2(-/-)) mice. TGF-ß1 bound normally to double-knockout mesangial cells. In wild-type mesangial cells, TGF-ß1 inhibited proliferation, but in double-knockout cells, it stimulated proliferation, promoted cell cycle progression, and reduced apoptosis; we could reverse this effect by reconstituting α1(VIII). Furthermore, in wild-type cells, TGF-ß1 mainly stimulated the Smad pathways, whereas in double-knockout cells, it activated the MAPK and PI3K/Akt pathways and induced expression of fibroblast growth factor 21 (FGF21). Inhibiting FGF21 expression by either interfering with activation of the MAPK and PI3K/Akt pathways or by FGF21 siRNA attenuated the TGF-ß1-induced proliferation of double-knockout mesangial cells. In vivo, diabetic double-knockout mice had significantly higher expression of renal FGF21 mRNA and protein compared with diabetic wild-type mice. Immunohistochemistry revealed strong expression of FGF21 in both glomerular (mesangial) and tubular cells of diabetic mice. Taken together, these data suggest that type VIII collagen significantly modulates the effect of TGF-ß1 on mesangial cells and may therefore play a role in the pathogenesis of diabetic nephropathy.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Contexto en salud:
6_ODS3_enfermedades_notrasmisibles
Problema de salud:
6_endocrine_disorders
Asunto principal:
Colágeno Tipo VIII
/
Proliferación Celular
/
Células Mesangiales
/
Factor de Crecimiento Transformador beta1
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
J Am Soc Nephrol
Asunto de la revista:
NEFROLOGIA
Año:
2011
Tipo del documento:
Article
País de afiliación:
Alemania