Progressive loss of vision associated with the disease Retinitis Pigmentosa (RP) is caused by cone cells starving from lack of nutrients and degrading their own parts, reports a study online in Nature Neuroscience. The results reveal a possible therapeutic target for the future treatment of RP.
Cones are light-sensing cells that mediate day-vision, whereas rod cells help us to see in darker conditions. Cones are not affected by the genetic mutations associated with RP, but there is a puzzling, progressive loss of cones that occurs with the disease.
Using mouse models of RP, Constance Cepko and colleagues found that cone cell death is caused by nutrient deprivation resulting from the loss of rod cells, which are affected by the genetic mutations associated with RP. This in turn, causes starving cones to break down their own cellular components and leads to the eventual complete loss of cones. The team also identified the insulin pathway as critical for this process, and found that systemic insulin injections improved cone survival in one mouse model of RP.
RP is associated with several different genetic mutations, but cone loss is a universal signature of the disease. This study therefore offers a plausible therapeutic target that could be used to treat the different varieties of RP.
Constance Cepko (Harvard Medical School, Boston, MA, USA)
Abstract available online.
(C) Nature Neuroscience press release.
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