J. Biol. Chem., Vol. 260, Issue 6, 3255-3258, 03, 1985
Increased cyclic GMP levels lead to a stimulation of elastin production in ligament fibroblasts that is reversed by cyclic AMP
RP Mecham, BD Levy, SL Morris, JG Madaras and DS Wrenn
The effects of cyclic nucleotides on elastin synthesis were studied in
ligamentum nuchae fibroblasts by adding exogenous cyclic nucleotide
derivatives or beta-adrenergic agents to cell culture medium. Elastin
synthesis was enhanced (approximately 80%) by dibutyryl cGMP (Bt2cGMP) in
concentrations ranging from 0.01 to 100 nM. Two other cGMP derivatives,
8-bromoguanosine 3':5'-cyclic monophosphate (8-Br-cGMP) and 2'-deoxy-cGMP,
were also potent stimulators of elastin synthesis. In the absence of
calcium, basal elastin production was substantially decreased (40% of
control) and cGMP analogs no longer stimulated elastin synthesis,
suggesting a role for calcium in the cGMP response. Bt2cAMP had no
demonstrable effect on elastin production except at high concentrations
which produced a nonspecific decrease equivalent to the decrease in total
protein synthesis. Similarly, elevation of endogenous cellular cAMP levels
by beta-adrenergic stimulation produced no change in elastin production.
When 8-Br-cGMP was added to cells together with Bt2cAMP, cGMP-dependent
stimulation of elastin production was abolished by cAMP in a dose-dependent
fashion. These results suggest a coordinated means by which elastin
production is controlled in ligament cells, i.e. increased cGMP levels lead
to a stimulation of elastin production that is reversed by cAMP.