Open AccessshRNA knockdown of guanylate cyclase 2e or cyclic nucleotide gated channel alpha 1 increases photoreceptor survival in a cGMP phosphodiesterase mouse model of retinitis pigmentosa
Author(s) -
Tosi Joaquin,
Davis Richard J.,
Wang NanKai,
Naumann Matthew,
Lin ChyuanSheng,
Tsang Stephen H.
Publication year - 2011
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2010.01201.x
Subject(s) - gene knockdown , small hairpin rna , retinitis pigmentosa , cyclic nucleotide gated ion channel , cyclic guanosine monophosphate , phosphodiesterase , microbiology and biotechnology , chemistry , biology , cyclic nucleotide , biochemistry , nucleotide , endocrinology , retinal , enzyme , apoptosis , nitric oxide , gene
In vertebrate rods, dark and light conditions produce changes in guanosine 3′,5′‐cyclic monophosphate (cGMP) and calcium (Ca 2+ ) levels, which are regulated by the opposing function of several proteins. During the recovery of a bright flash, guanylate cyclase (GUCY) helps raise cGMP to levels that open cGMP‐gated calcium sodium channels (CNG) to increase Na + and Ca 2+ influx in the outer segment. In contrast, light activates cGMP phosphodiesterase 6 (PDE6) causing rapid hydrolysis of cGMP, CNG closure, and reduced Na + and Ca 2+ levels. In Pde6b mouse models of retinitis pigmentosa (RP), photoreceptor death is preceded by abnormally high cGMP and Ca 2+ levels, likely because of continued synthesis of cGMP by guanylate cyclases and unregulated influx of Ca 2+ to toxic levels through CNG channels. To reverse the effects of Pde6b loss of function, we employed an shRNA knockdown approach to reduce the expression of Gucy2e or Cnga1 in Pde6b H620Q photoreceptors prior to degeneration. Gucy2e ‐ or Cnga1 ‐shRNA lentiviral‐mediated knockdown GUCY2E and CNGA1 expression increase visual function and photoreceptor survival in Pde6b H620Q mice. We demonstrated that effective knockdown of GUCY2E and CNGA1 expression to counteract loss of PDE6 function may develop into a valuable approach for treating some patients with RP.