The protein profile of fibroblasts: the role of proteomics.

Fibroblasts represent one of the most widely used cell types to investigate the biology of connective tissues in normal and pathologic conditions. Aim of the present review is to emphasize, in the light of the current literature, the importance of fibroblast proteomics as a powerful resource for functional genomics in health and disease. Only very recently, proteomic techniques has been applied to characterise human dermal fibroblasts, but few data are available concerning fibroblasts of various animal origins or derived from different tissues. Functional proteomic methods have been successfully used in order i) to investigate changes in protein synthesis resulting from stimulation of fibroblasts with exogenous and endogenous factors and in the presence of conditioned media; ii) to identify the underlying mechanisms that modulate fibroblast protein profile during senescence; iii) to obtain increased knowledge about the pathogenesis of diseases such as peribronchial fibrosis; iv) to better understand the molecular basis of biocompatibility. In addition, comparison of data obtained by proteome analysis, on in vitro aged human embryo fibroblasts and on in vitro cultured human fibroblasts from subjects of different ages, allowed differences and similarities of the aging process in different models to be highlighted. Although the number of proteomic studies has exponentially increased during the past couple of years, several proteins are still under-represented in most proteome maps, i.e. membrane, low abundant and basic proteins. Since a comprehensive proteomic approach must use a technology platform that is not biased against any protein class and is able to resolve co- and post-translationally modified forms of proteins, we exemplify here the major technical improvements in protein separation and identification. Moreover, glycosylation is the most common type of post-translational protein modification, and a special emphasis is therefore placed on the expanding role of glycomics.