Abstract
Purpose::
The activated fibroblasts (FBs) represent the main cell type involved in tissue remodelling/fibrosis that occurs in Ocular Cicatricial Pemphigoid (OCP). During these processes, FB differentiate into myofibroblasts (myoFBs) highly expressing smooth muscle actin (α-SMA) cells. MyoFBs express both trkANGFR and p75NTR and represent a sources/targets of Nerve growth factor (NGF). In this study we sought to investigate the presence of α-SMA positive cells in OCP, their trkANGFR and p75NTR expression, and the possible NGF modulation of their α-SMA expression in vitro.
Methods::
Conjunctival samples from 4 patients with OCP and 2 healthy controls were processed for α-SMA, NGF, trkANGFR and p75NTR expression by immunohistochemistry, confocal microscopy, ELISA; Western Blot and Real Time PCR. Primary culture of OCP-derived and healthy FBs were evaluated for α-SMA, NGF, trkANGFR and p75NTR expression by PCR, FACS and confocal analysis. Moreover, OCP derived and healthy FBs were exposed to increasing NGF concentrations (1-10-50-100ng/mL, 24hrs) to evaluate/compare the α-SMAmRNA and protein expression.
Results::
OCP stroma was characterized by the presence of α-SMA positive cells and strong NGF, trkANGFR and p75NTR positivity. p75NTR , and to a less extend trkANGFR , were found co-expressed with α-SMA. In OCP-derived FBs, NGFmRNA and α-SMAmRNA were increased while p75mRNA and trkAmRNA were decreased in comparison to healthy FBs. NGF treatment induces a decrease expression of α-SMAmRNA by OCP derived FBs, while stimulates α-SMAmRNA increase by healthy derived FBs.
Conclusions::
α-SMA and NGF increased in OCP stroma and derived FBs. The fact that OCP-FBs, bearing trkANGFR and p75NTR , respond to NGF by modulating their α-SMA expression, might suggest a possible role for NGF in the remodelling process occurring in OCP disease.
Keywords: autoimmune disease • conjunctiva • growth factors/growth factor receptors