Efeito da cistamina na distrofia óculo-faríngea em camundongos
USA - a distrofia óculo-faríngea ocorre por uma repetição de trinucleotídeos que acarreta agregação de uma proteína mutante no núcleo das células musculares; em células de camundongos com distrofia tipo óculo-faríngea e in vivo os autores estudaram os efeitos da cistamina. A droga causou uma menor agregação da proteína, reduz a fraqueza e as alterações patológicas dos camundongos. A droga inibe uma enzima, a transglutaminase 2 e deve ser estudada como uma provável opção terapêutica para a doença.
O resumo em inglês pode ser lido abaixo:
(Science Translational Medicine, Jun 2010; 2: 34ra40) Cystamine Suppresses Polyalanine Toxicity in a Mouse Model of Oculopharyngeal Muscular Dystrophy
Janet E. Davies, Claudia Rose, Sovan Sarkar, and David C. Rubinsztein
Oculopharyngeal muscular dystrophy (OPMD) is caused by a trinucleotide repeat expansion mutation in the coding region of the gene encoding PABPN1 (polyadenylate-binding protein nuclear 1). Mutant PABPN1 with a polyalanine tract expansion forms aggregates within the nuclei of skeletal muscle fibers. There is currently no effective treatment. We have developed cell and mouse models of OPMD and have identified the aggregation of mutant PABPN1 and apoptosis as therapeutic targets. Here, we show that transglutaminase activity is increased in muscle from OPMD model mice. Elevated transglutaminase 2 expression enhances, whereas TG2 knockdown suppresses, the toxicity and aggregation of mutant PABPN1 in cells. Cystamine protects against the toxicity of mutant PABPN1 and exerts its effect via the inhibition of transglutaminase 2, as cystamine treatment is unable to further reduce the protective effect of transglutaminase 2 knockdown on mutant PABPN1 toxicity in cells. Cystamine also reduces the aggregation and toxicity of mutant PABPN1 in human cells. In a mouse model of OPMD, cystamine treatment reduced the elevated transglutaminase activity, attenuated muscle weakness, reduced aggregate load, and decreased apoptotic markers in muscle. Therefore, inhibitors of transglutaminase 2 should be considered as possible therapeutics for OPMD
Fonte: http://distrofiamuscular.net/noticias.htm |
