Fibroblasts: Important producers and targets of inflammatory prostaglandins in the lungs
To evaluate whether such prostaglandins can alter lung connective tissue secretion by lung fibroblasts, the ability of prostaglandins to modulate the secretion of collagen and fibronectin by HFL-1 cells was determined using an enzyme immunoassay for human type I collagen and for human fibronectin. PGE1 and PGE2 caused a 29 ± 6% reduction in type I collagen secretion but, in contrast, a 39 ± 7% increase in fibronectin secretion (p < 0.01, all comparisons to control). In contrast, PGF(2α), (a prostaglandin which frequently has effects opposite those of PGE1 and PGE2) had no effect on type I collagen secretion (99 ± 7% of control, p > 0.2) bu caused a 20 ± 3% reduction in fibronectin secretion (p < 0.05). Thus fibroblasts are capable of specific modulation of connective macromolecule secretion in response to progstaglandins. Both through the production of prostaglandins and as a target for these mediators, lung fibroblasts play an important role in the cellular response to lung inflammation.