Role of retinoid X receptors on survival and modulation of inflammatory response in retinal pigment epithelium cells, upon different stressors, such as H2O2 and viral infection.

AYALA PEÑA, VICTORIA; ARMIENTO, MARÍA NIEVES; SCOLARO, LUIS; GERMAN O LORENA

Mar del Plata

Jornada; SAIC 2016; 2016

Sociedad Argentina de Investigación Clínica

Resumen preliminar:Age-related macular degeneration (AMD) is the main pathology leading to blindness in adults and has currently no cure or effective treatment. Retinal pigment epithelial (RPE) cells have immunomodulatory properties and their degeneration contributes in the development of AMD. Oxidative stress is one of the events involved in the pathogenesis of this disease, and herpes simplex virus type 1 (HSV-1) infection is currently proposed as a probable risk factor. We previously demonstrated that RXR activation with HX630 protects RPE (D407) cells from H2O2-induced apoptosis. HX630 prevents p65NFκB nuclear translocation (which is also crucial for triggering inflammation) and increases PPARγ mRNA levels. LG100754 (an antagonist of RXR homodimers and a RXR agonist that could act through RXR/PPARγ heterodimer) also had a protective effect. In this work using a PPARγ specific agonist and their antagonist we reproduced the protective effect of RXR activation against oxidative damage in D407cells, determined by MTT assay and fluorescence microscopy. We observed by qRT-PCR that RXR activation decreased the IL-6 mRNA (a pro-inflammatory cytokine) and increased the IL-10 and TGFβ (anti-inflammatory cytokines) mRNA levels significantly. Moreover, in D407 cells infected with HSV-1, which is known to block the synthesis of RXRα in macrophage promoting the host antiviral response, PPARγ mRNA level but not RXRα was significantly decreased compared to mock infected cultures, even under LG100754 treatment. Using fluorescence microscopy, p65NFkB protein level was increased in the whole cell; however, the nuclear/total p65NFkB fluorescence proportion in infected cells was decreased compared to the mock infected cells, even under LG100754 treatment. Furthermore, the infection blocked the synthesis of TGFβ mRNA and the RXR agonist could not improve it. All in all, our results suggest that the RXR/PPARγ heterodimers would be a central signaling in survival and inflammatory response upon H2O2 in RPE cells, which could be regulated by HSV-1 infection.