Increased bioavailability of cyclic guanylate monophosphate prevents retinal ganglion cell degeneration.

Increased bioavailability of cyclic guanylate monophosphate prevents retinal ganglion cell degeneration. Neurobiol Dis. 2018 Sep 10;: Authors: Wareham LK, Dordea AC, Schleifer G, Yao V, Batten A, Fei F, Mertz J, Gregory-Ksander M, Pasquale LR, Sappington RM, Buys ES Abstract The nitric oxide - guanylyl cyclase-1 - cyclic guanylate monophosphate (NO-GC-1-cGMP) pathway has emerged as a potential pathogenic mechanism for glaucoma, a common intraocular pressure (IOP)-related optic neuropathy characterized by the degeneration of retinal ganglion cells (RGCs) and their axons in the optic nerve. NO activates GC-1 to increase cGMP levels, which are lowered by cGMP-specific phosphodiesterase (PDE) activity. This pathway appears to play a role in both the regulation of IOP, where reduced cGMP levels in mice leads to elevated IOP and subsequent RGC degeneration. Here, we investigated whether potentiation of cGMP signaling could protect RGCs from glaucomatous degeneration. We administered the PDE5 inhibitor tadalafil orally (10 mg/kg/day) in murine models of two forms of glaucoma - primary open angle glaucoma (POAG; GC-1-/- mice) and primary angle-closure glaucoma (PACG; Microbead Occlusion Model) - and measured RGC viability at both the soma and axon level. To determine the direct effect of increased cGMP on RGCs in vitro, we treated axotomized whole retina and primary RGC cultures with the cGMP analogue 8-Br-cGMP. Tadalafil treatment increas...
Source: Neurobiology of Disease - Category: Neurology Authors: Tags: Neurobiol Dis Source Type: research