Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exposure to light contributes to the development and progression of retinal degenerative diseases. However, the mechanisms underlying light-induced tissue damage are not fully understood. Here, we examined the role of angiotensin II type 1 receptor (AT1R) signaling, which is part of the renin-angiotensin system, in light-induced retinal damage. Light-exposed Balb/c mice that were treated with the AT1R blockers (angiotensin II receptor blockers; ARBs) valsartan, losartan, and candesartan before and after the light exposure exhibited attenuated visual function impairment, compared to vehicle-treated mice. This effect was dose-dependent and observed across the ARB class of inhibitors. Further evaluation of valsartan showed that it suppressed a number of light-induced retinal effects, including thinning of the photoreceptor cell layer caused by apoptosis, shortening of the photoreceptor cell outer segment, and increased levels of reactive oxygen species (ROS). The role of ROS in retinal pathogenesis was investigated further using the antioxidant N-acetyl-l-cysteine (NAC). Treatment of light-exposed mice with NAC before the light exposure suppressed the visual function impairment and photoreceptor cell histological changes due to apoptosis. Moreover, treatment with valsartan or NAC suppressed the induction of c-fos (a component of the AP-1 transcription factor) and the upregulation of fasl (a proapoptotic molecule whose transcript is regulated downstream of AP-1). Our results suggest that AT1R signaling mediates light-induced apoptosis, by increasing the levels of ROS and proapoptotic molecules in the retina. Thus, AT1R blockade may represent a new therapeutic approach for preventing light-induced retinal neural tissue damage.
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PMID:Angiotensin II type 1 receptor blockade suppresses light-induced neural damage in the mouse retina. 2466 96

The CLN2 form of neuronal ceroid lipofuscinosis is an autosomal recessively inherited lysosomal storage disease that is characterized by progressive vision loss culminating in blindness, cognitive and motor decline, neurodegeneration, and premature death. CLN2 disease results from mutations in the gene that encodes the soluble lysosomal enzyme tripeptidyl peptidase-1. A null mutation in the TPP1 gene encoding this enzyme causes a CLN2-like disease in Dachshunds. Dachshunds that are homozygous for this mutation serve as a model for human CLN2 disease, exhibiting clinical signs and neuropathology similar to those of children with this disorder. Affected dogs reach end-stage terminal disease status at 10-11 months of age. In addition to retinal changes typical of CLN2 disease, a retinopathy consisting of multifocal, bullous retinal detachment lesions was identified in 65% of (TPP1-/-) dogs in an established research colony. These lesions did not occur in littermates that were heterozygous or homozygous for the normal TPP1 allele. Retinal changes and the functional effects of this multifocal retinopathy were examined objectively over time using ophthalmic examinations, fundus photography, electroretinography (ERG), quantitative pupillary light response (PLR) recording, fluorescein angiography, optical coherence tomography (OCT) and histopathology. The retinopathy consisted of progressive multifocal serous retinal detachments. The severity of the disease-related retinal thinning was no more serious in most detached areas than in adjacent areas of the retina that remained in close apposition to the retinal pigment epithelium. The retinopathy observed in these dogs was somewhat similar to canine multifocal retinopathy (CMR), a disease caused by a mutation of the bestrophin gene BEST1. ERG a-wave amplitudes were relatively preserved in the Dachshunds with CLN2 disease, whether or not they developed the multifocal retinopathy. The retinopathy also had minimal effects on the PLR. Histological evaluation indicated that the CLN2 disease-related retinal degeneration was not exacerbated in areas where the retina was detached except where the detached areas were very large. DNA sequence analysis ruled out a mutation in the BEST1 exons or splice junctions as a cause for the retinopathy. Perfect concordance between the TPP1 mutation and the retinopathy in the large number of dogs examined indicates that the retinopathy most likely occurs as a direct result of the TPP1 mutation. Therefore, inhibition of the development and progression of these lesions can be used as an indicator of the efficacy of therapeutic interventions currently under investigation for the treatment of CLN2 disease in the Dachshund model. In addition, these findings suggest that TPP1 mutations may underlie multifocal retinopathies of unknown cause in animals and humans.
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PMID:Multifocal retinopathy in Dachshunds with CLN2 neuronal ceroid lipofuscinosis. 2569 10