Purpose: Oxidative stress, inflammation, protein aggregation, are major features of Age-related Macular Degeneration (AMD). A primary system used by the RPE to neutralize oxidative stress and maintain cellular homeostasis is the transcription nuclear factor E2-related factor 2 (Nrf2) pathway, whose impairment in AMD is documented. Many Nrf2 targets with a role in AMD are also regulated at post-transcriptional level by the RNA-binding protein HuR/ELAVL1. However, the role of HuR and post-transcriptional control of gene expression in AMD is largely unexplored. We studied the pattern of HuR expression in vitro and in vivo contexts characterized by Nrf2 impairment, as well as in AMD human specimens. Methods: HuR protein pattern was evaluated by Western blot and immunostaining. Wild type (WT) and Nrf2-deficient ARPE-19 cells were used for in vitro study. Retinas from mice deficient in either Nrf-2 (Nrf-2 single knockout, sKO), or both Nrf-2 and PGC-1α (Nrf-2/PGC-1α double knockout, dKO) at one year of age, as well as retinas from age-matched WT controls, were used for in vivo study. Retinas from human AMD and control subjects were also analysed for HuR expression. Results: Nrf2-deficient ARPE-19 cells show increased HuR levels. Retina from sKO, and especially dKO mice, present an altered HuR expression pattern, mainly featured by higher HuR levels in RPE in comparison to WT animals. Changes in HuR immunostaining were also evident in other retinal layers, such as RGL. Immunohistochemistry performed on a limited number of human retinal specimens suggests altered HuR content in RPE. Conclusion: HuR expression pattern dramatically changes in Nrf2-deficient contexts, especially in those featured by elevated oxidative stress, suggesting that a cross-talk between Nrf2 and HuR pathways exists. These findings represent a step forward a better understanding of the modification of the post-transcriptional factors in AMD, and suggest that HuR may be relevant in AMD pathophysiology.
The HuR/ELAVL1 expression is altered in Nrf2-deficient contexts
Marialaura Amadio
;Stefano GovoniMembro del Collaboration Group
;
2019-01-01
Abstract
Purpose: Oxidative stress, inflammation, protein aggregation, are major features of Age-related Macular Degeneration (AMD). A primary system used by the RPE to neutralize oxidative stress and maintain cellular homeostasis is the transcription nuclear factor E2-related factor 2 (Nrf2) pathway, whose impairment in AMD is documented. Many Nrf2 targets with a role in AMD are also regulated at post-transcriptional level by the RNA-binding protein HuR/ELAVL1. However, the role of HuR and post-transcriptional control of gene expression in AMD is largely unexplored. We studied the pattern of HuR expression in vitro and in vivo contexts characterized by Nrf2 impairment, as well as in AMD human specimens. Methods: HuR protein pattern was evaluated by Western blot and immunostaining. Wild type (WT) and Nrf2-deficient ARPE-19 cells were used for in vitro study. Retinas from mice deficient in either Nrf-2 (Nrf-2 single knockout, sKO), or both Nrf-2 and PGC-1α (Nrf-2/PGC-1α double knockout, dKO) at one year of age, as well as retinas from age-matched WT controls, were used for in vivo study. Retinas from human AMD and control subjects were also analysed for HuR expression. Results: Nrf2-deficient ARPE-19 cells show increased HuR levels. Retina from sKO, and especially dKO mice, present an altered HuR expression pattern, mainly featured by higher HuR levels in RPE in comparison to WT animals. Changes in HuR immunostaining were also evident in other retinal layers, such as RGL. Immunohistochemistry performed on a limited number of human retinal specimens suggests altered HuR content in RPE. Conclusion: HuR expression pattern dramatically changes in Nrf2-deficient contexts, especially in those featured by elevated oxidative stress, suggesting that a cross-talk between Nrf2 and HuR pathways exists. These findings represent a step forward a better understanding of the modification of the post-transcriptional factors in AMD, and suggest that HuR may be relevant in AMD pathophysiology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
