Using Proteomic Analysis for Studying the Skin Fibroblast Protein Profile in Systemic Sclerosis

Increased efforts have been made during the last few decades to develop new technologies capable of identifying and quantifying the expression proteome in different cellular systems in physiological and physiopathological conditions for determining illness biomarkers, pharmaceutical targets and/or posttranslational modifications (PTM) by means of proteomic techniques. 2D gel electrophoresis, with immobilized pH gradients, associated with mass spectrometry, is one of the fundamentals steps in studying proteomics. The 2D technique can be used in studying the quantitative expression of protein profiles according to iso-electric point (Ip), molecular weight (Mr), protein solubility and the relative abundance of the above. This methodology provides a protein profile reflecting changes in protein expression levels, isoforms and PTM. Proteins can be classified into those known by their structure and function, those recognized by determined domains and about which there is some knowledge, and those whose function is still not known. Proteomics is defined as the large-scale study of proteins expressed for a specific tissue from a genome, (global proteomics) or differentially expressed proteins (differential proteomics). Determining differentially expressed proteins, or proteins suffering a change in physiological circumstances, is the clue to understanding such pathology’s cellular mechanisms. Although an expressed gene in specific tissues (as an answer to biologic alterations) could be analyzed by a mRNA expression study (transcriptomics), these results do not always coincide with the expected expression profiles since the number and activity of proteins associated with the same regulation in different stages could be modified. Genomic data integration is required, as well as transcritomics