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Shivani Kumaresan, Abdelsalam Sharkasi, Ravirajsinh Jadeja, Hossameldin Abouhish, Pamela M Martin, Manuela Bartoli, Menaka Thounaojam; Altered balance of miR-144-3p and miR-124-5p regulates amyloid-beta autocrine production in retinal pigment epithelial cells. Invest. Ophthalmol. Vis. Sci. 2020;61(7):1536.
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The accumulation of Amyloid-Beta peptides (Aβ) is associated with age-related macular degeneration (AMD). The mechanisms regulating production and accumulation of Aβ in retinal pigment epithelium (RPE) are still under investigation. Recent studies have shown that epigenetic mechanisms involving microRNAs (miRs) could play a role in AMD pathogenesis. Here we have investigated autocrine production of Aβ in RPE and ascertained the role of miR-144-3p and miR-124-5p in this process. In particular, we have investigated the effects of these miRs on switching the cleavage of the amyloid precursor protein (APP) towards the neurotoxic amyloidogenic pathway, dependent on the activity of BACE-1 (β-site APP-cleaving enzyme 1), a predicted target of miR-124-5p, at the expenses of the neuroprotective non-amyloidogenic pathway, dependent on ADAM10, which is a predicted target of miR-144-3p.
Human retinal pigment epithelial cells (HuRPE) were treated for 12 h with oligomers of Aβ (1-42) (5µM) or the reverse peptide Aβ (42-1), used as negative control. QPCR analysis was performed to quantify the expression of miR-144-3p and miR-124-5p. ADAM10 and BACE1 mRNA and protein expressions were quantified by QPCR and Western blot, respectively. HuRPE were transfected with miR-144-3p mimic or inhibitor for 48h and the expression of ADAM10, APP, and BACE1 was assessed at mRNA and protein level by QPCR and Western blot, respectively.
Treatment of HuRPE with Aβ (1-42) resulted in significant up regulation of miR-144-3p and down-regulation of miR-124-5p levels. Similarly, treatments of HuRPE with Aβ (1-42) lowered levels of ADAM10 while up-regulating the expression of BACE1. In all cases treatments of the cells with same doses of the reverse peptide, Aβ (42-1) had no effects. Overexpression of miR-144-3p mimic, produced the same effects of Aβ (1-42) decreasing ADAM10 while increasing BACE1 expression. Whereas, inhibition of miR-144-3p by transfection of the cells with a specific antagomiR counteracted the effects of Aβ (1-42) on HuRPE
Our results demonstrate the importance of miR-144 and miR-124 inverse relationships in regulating Aβ autocrine production in RPE cells. Thus, our data suggest that therapeutic strategies controlling or monitoring the expression of these miRs could potentially be useful as diagnostic or therapeutic tools for AMD
This is a 2020 ARVO Annual Meeting abstract.
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