Introduction:Vogt-Koyanagi-Harada syndrome is a rare, inflammatory disease with manifestations affecting the ocular, central nervous, audito-vestibular, and integumentary systems. Vogt-Koyanagi-Harada syndrome is more...Introduction:Vogt-Koyanagi-Harada syndrome is a rare, inflammatory disease with manifestations affecting the ocular, central nervous, audito-vestibular, and integumentary systems. Vogt-Koyanagi-Harada syndrome is more frequent in Asia but is also described in Europe. We report three new non asiatic cases of this syndrome. Observations:The three patients had bilateral panuveitis and hypoacusia. Two of them had peripheral facial palsy, two of them had vestibular syndrome and one of them lymphocytic meningitis. In each case we found characteristic HLA II typing and in one case we discovered the simultaneous presence of three auto-antibodies: anti-retina (anti-Arrestin type), anti-choroid and anti-cochlea. These patients were treated by corticosteroids but required an additional treatment by cyclophosphamide (0.8g/m2). The clinical course was favorable with visual sequelae for two and auditory one for one. Discussion:These biological and therapeutic elements and a review of the recent literature are in favor of an autoimmune origin of this syndrome.展开更多
Retinal progenitor cells （RPCs） are neural stem cells able to differentiate into any normal adult retinal cell type, except for pigment epithelial cells. Retinoic acid （RA） is a powerful growth/differentiation fac...Retinal progenitor cells （RPCs） are neural stem cells able to differentiate into any normal adult retinal cell type, except for pigment epithelial cells. Retinoic acid （RA） is a powerful growth/differentiation factor that generally causes growth inhibition, differentiation and/or apoptosis. In this study, we demonstrate that RA not only affects mouse RPC differentiation but also improves cell survival by reducing spontaneous apoptotic rate without affecting RPC proliferation. The enhanced cell survival was accompanied by a significant upregulation of the expression of protein kinase A （PKA） and several protein kinase C （PKC） isoforms. Treatment of cells grown in RA-free media with 8-bromoadenosine3＇,5＇-cyclic monophosphate, a known activator of PKA, resulted in an anti-apoptotic effect similar to that caused by RA; whereas the PKA inhibitor N-[2-（p-bromocinnamylamino）ethyl]-5-isoquinolinesul- fonamide dihydrochloride led to a significant （-32%） increase in apoptosis. In contrast, treatment of RPCs with any of two PKC selective inhibitors, 2,2＇,3,3＇,4,4＇-hexahydroxy-1,1 ＇-biphenyl-6,6＇-dimethanol dimethyl ether and bisindolylmaleimide XI, led to diminished apoptosis; while a PKC activator, phorbol 12-myristate 13-acetate, increased apoptosis. These and other data suggest that the effect of RA on RPC survival is mostly due to the increased anti-apoptotic activity elicited by PKA, which might in turn be antagonized by PKC. Such a mechanism is a new example of tight regulation of important biological processes triggered by RA. Although the detailed mechanisms remain to be elucidated, we provide evidence that the pro-survival effect of RA on RPCs is not mediated by changed expression of p53 or bcl-2, and appears to be independent of 15-amyloid, Fas ligand, TNF-α, ganglioside GM1 and ceramide C 16-induced apoptotic pathways.展开更多
文摘Introduction:Vogt-Koyanagi-Harada syndrome is a rare, inflammatory disease with manifestations affecting the ocular, central nervous, audito-vestibular, and integumentary systems. Vogt-Koyanagi-Harada syndrome is more frequent in Asia but is also described in Europe. We report three new non asiatic cases of this syndrome. Observations:The three patients had bilateral panuveitis and hypoacusia. Two of them had peripheral facial palsy, two of them had vestibular syndrome and one of them lymphocytic meningitis. In each case we found characteristic HLA II typing and in one case we discovered the simultaneous presence of three auto-antibodies: anti-retina (anti-Arrestin type), anti-choroid and anti-cochlea. These patients were treated by corticosteroids but required an additional treatment by cyclophosphamide (0.8g/m2). The clinical course was favorable with visual sequelae for two and auditory one for one. Discussion:These biological and therapeutic elements and a review of the recent literature are in favor of an autoimmune origin of this syndrome.
文摘Retinal progenitor cells （RPCs） are neural stem cells able to differentiate into any normal adult retinal cell type, except for pigment epithelial cells. Retinoic acid （RA） is a powerful growth/differentiation factor that generally causes growth inhibition, differentiation and/or apoptosis. In this study, we demonstrate that RA not only affects mouse RPC differentiation but also improves cell survival by reducing spontaneous apoptotic rate without affecting RPC proliferation. The enhanced cell survival was accompanied by a significant upregulation of the expression of protein kinase A （PKA） and several protein kinase C （PKC） isoforms. Treatment of cells grown in RA-free media with 8-bromoadenosine3＇,5＇-cyclic monophosphate, a known activator of PKA, resulted in an anti-apoptotic effect similar to that caused by RA; whereas the PKA inhibitor N-[2-（p-bromocinnamylamino）ethyl]-5-isoquinolinesul- fonamide dihydrochloride led to a significant （-32%） increase in apoptosis. In contrast, treatment of RPCs with any of two PKC selective inhibitors, 2,2＇,3,3＇,4,4＇-hexahydroxy-1,1 ＇-biphenyl-6,6＇-dimethanol dimethyl ether and bisindolylmaleimide XI, led to diminished apoptosis; while a PKC activator, phorbol 12-myristate 13-acetate, increased apoptosis. These and other data suggest that the effect of RA on RPC survival is mostly due to the increased anti-apoptotic activity elicited by PKA, which might in turn be antagonized by PKC. Such a mechanism is a new example of tight regulation of important biological processes triggered by RA. Although the detailed mechanisms remain to be elucidated, we provide evidence that the pro-survival effect of RA on RPCs is not mediated by changed expression of p53 or bcl-2, and appears to be independent of 15-amyloid, Fas ligand, TNF-α, ganglioside GM1 and ceramide C 16-induced apoptotic pathways.
