Sustained small and intermediate size proteins expression in phorbol 12-myristate 13-acetate/ionomycine prolonged stimulated human fibroblasts

ABSTRACT

Objective To compare the protein profile of culture supernatants in stimulated and unstimulated human fibroblasts to find some proteins indicating the presence of fibroblasts and their activation status. Methods Dermal fibroblasts were stimulated with phorbol 12-myristate 13-acetate (PMA)/ionomycine for 72 h. MTT assay was done to determine cell viability and A/E fluorescent staining was used to evaluate the cell death pattern. Protein analysis was performed by gradient SDS polyacrylamide gel electrophoresis 8%–16%. Results The supernatant of 24 h cultured both stimulated and unstimulated fibroblasts showed two bands in SDS-PAGE analysis with relative molecular weights of 8.59 and 78.8 kDa. These bands density was decreased during the next 48 h in unstimulated cells while their expression was continued in PMA or PMA/ionomycine stimulated cells and a new 85.3 kDa band was appeared in unstimulated and 72 h PMA stimulated cells. Moreover, we found another seven small size (10–19.5 kDa) proteins in supernatants of 48 h and 72 h unstimulated but not in PMA or PMA/Ionomycine stimulated fibroblasts. Most of these proteins expression were down regulated following fibroblast activation. This down-regulation is consistent with our finding that PMA or PMA/ionomycine stimulated cells exhibited a significant level of apoptosis cell death. Conclusions Human fibroblasts produce some small to intermediate sized proteins with specific SDS-PAGE profile upon cell activation. Most of these proteins can be excreted in urine and can be immunogen theoretically so this data provided a reliable clue for fibrosis biomarker screening based on designation of an appropriated immunoassay.