Nerve growth factor has a modulatory role on human primary fibroblast cultures derived from vernal keratoconjunctivitis-affected conjunctiva.
OBJECTIVE
To evaluate the role of nerve growth factor (NGF) in remodeling processes of vernal keratoconjunctivitis (VKC). VKC is a chronic inflammatory disorder of the conjunctiva and is characterized by marked tissue remodeling. NGF, a pleiotrophic factor with documented profibrogenic activities, is produced by inflammatory and structural cells populating the VKC conjunctiva and is increased in the serum and tears of VKC patients.


METHODS
Primary cultures of VKC-derived fibroblasts (VKC-FBs) were exposed to increasing NGF concentrations (1-500 ng/ml) to evaluate and compare the expression of alpha-smooth muscle actin (alphaSMA, a defining myofibroblast marker), collagens (types I and IV), and metalloproteinases and tissue inhibitors (MMP9/TIMP1, MMP2/TIMP2) at the biochemical as well as molecular levels.


RESULTS
Endogenous NGF was increased in the VKC-FB supernatant, as compared to healthy-FB supernatant. VKC-FBs expressed alphaSMA and increased types I and IV collagens. VKC-FBs, and in particular all alphaSMA positive cells, expressed both trkA(NGFR) and p75(NTR), while healthy-FBs only expressed trkA(NGFR). Exogenous NGF did not change alphaSMA expression, while alphaSMA expression was enhanced by specific neutralization of p75(NTR). NGF (10 ng/ml) exposure significantly decreased type I collagen expression, without affecting type IV collagen, and increased MMP9mRNA and protein.


CONCLUSIONS
The autocrine modulation of differentiation and response of VKC-FBs to NGF exposure with downregulation of type I collagen and upregulation of MMP9 expression supports a relevant role for NGF in tissue remodeling of VKC.
Micera
Alessandra
A
CIR Laboratory of Ophthalmology, University Campus Bio-medico, Rome, Italy.
Lambiase
Alessandro
A
Stampachiacchiere
Barbara
B
Sgrulletta
Roberto
R
Normando
Eduardo Maria
EM
Bonini
Sergio
S
Bonini
Stefano
S
D000199:Actins / Q000378:metabolism; D000293:Adolescent; D000818:Animals; D002478:Cells, Cultured; D002648:Child; D024042:Collagen Type I / Q000378:metabolism; D024141:Collagen Type IV / Q000378:metabolism; D003228:Conjunctiva / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology*; D003233:Conjunctivitis, Allergic / Q000473:pathology* / Q000503:physiopathology*; D015536:Down-Regulation; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009130:Muscle, Smooth / Q000378:metabolism; D020932:Nerve Growth Factor / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D020800:Receptor, Nerve Growth Factor / Q000378:metabolism; D020917:Receptor, trkA / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
D000199:Actins; D024042:Collagen Type I; D024141:Collagen Type IV; D012333:RNA, Messenger; D020800:Receptor, Nerve Growth Factor; D020932:Nerve Growth Factor; D020917:Receptor, trkA; D020780:Matrix Metalloproteinase 9