Reduced programmed cell death in the retina and defects in lens and cornea of Tgfbeta2(-/-) Tgfbeta3(-/-) double-deficient mice.
We have previously shown that immunoneutralization of transforming growth factor-beta (TGF-beta) in the chick embryo significantly reduces programmed cell death (PCD) in peripheral neurons, spinal cord, and retina. In order to validate these results we have begun to analyze PCD in mice with targeted ablations of the TGF-beta2 and TGF-beta3 genes. Recent analyses of mice lacking TGF-beta3 had failed to reveal an overt eye phenotype, while retinae of TGF-beta2-deficient mice showed retinal hypercellularity. We report now that eyes of Tgfbeta2/Tgfbeta3 double-deficient mice display severe alterations in the morphology of the retina, lens, and cornea. The inner neural retina-the region where TGF-beta receptor (TbetaR) I and II immunoreactivities are most prominent-is significantly thickened, and numbers of TUNEL-positive cells are significantly reduced compared to wild-type littermates. In Tgfbeta2(-/-) Tgfbeta3(-/-) and Tgfbeta2(-/-) Tgfbeta3(+/-) littermates the retina was consistently detached from the underlying pigment epithelium. Cornea, corneal stroma, and lens epithelium were significantly thinner in these mutants. In contrast, retinal morphology in Tgfbeta2(+/-) Tgfbeta3(-/-)mutant littermates resembles the situation observed in wild-type retinae except for the retinal detachment. Thus, regression in the thickness of cornea and corneal stroma seems to be TGF-beta isoform and gene dose dependent. Our results substantiate the notion based on previous analyses of chick embryos with reduced levels of endogenous TGF-beta that TGF-beta, most notably TGF-beta2, is required to mediate PCD in developing retinal cells in vivo. Moreover, our data indicate that TGF-betas play essential roles in cornea and lens development.
Dünker
Nicole
N
Center of Anatomy, Department of Neuroanatomy, Georg August University Göttingen, 37075, Göttingen, Germany. nduenke@gwdg.de
Krieglstein
Kerstin
K
D030201:Activin Receptors, Type I / Q000032:analysis; D000818:Animals; D017209:Apoptosis / Q000235:genetics* / Q000502:physiology; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D003315:Cornea / Q000737:chemistry / Q000196:embryology / Q000473:pathology*; D003319:Corneal Stroma / Q000196:embryology / Q000473:pathology; D003433:Crosses, Genetic; D005123:Eye / Q000196:embryology / Q000294:innervation / Q000473:pathology; D005260:Female; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007908:Lens, Crystalline / Q000737:chemistry / Q000196:embryology / Q000473:pathology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009900:Optic Nerve / Q000737:chemistry / Q000196:embryology / Q000473:pathology; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis / Q000276:immunology; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000032:analysis; D012160:Retina / Q000737:chemistry / Q000196:embryology / Q000473:pathology*; D012163:Retinal Detachment / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000235:genetics*; D053781:Transforming Growth Factor beta2; D053782:Transforming Growth Factor beta3
D018809:Proliferating Cell Nuclear Antigen; D018125:Receptors, Transforming Growth Factor beta; C509045:Tgfb3 protein, mouse; D016212:Transforming Growth Factor beta; D053781:Transforming Growth Factor beta2; D053782:Transforming Growth Factor beta3; D017346:Protein Serine-Threonine Kinases; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II