Abstract
Purpose: :
Macrophages have been implicated in the pathogenesis of age-related macular degeneration (AMD) and endogenous microRNAs have been reported play important role in regulating macrophage function by modulating gene expression. Our hypothesis proposes there are different patterns of microRNA expression in peripheral blood monocytes from subjects with dry AMD versus age-matched control subjects without AMD.
Methods: :
Peripheral blood was obtained from nine patients with dry AMD and two age-matched control subjects. Peripheral blood monocytes were isolated utilizing established antibody based methods. RNA was isolated and assessed for quality. Microarray analysis was performed to assess the relative expression levels of microRNA transcripts (Miltenyi Biotec). Differentially expressed microRNAs were validated using quantitative real time RT-PCR.
Results: :
Among 872 human microRNAs, 18 were up-regulated, 2 were down regulated in at least half of the AMD patients. Ten of the identified microRNAs have specific gene targets. Mir-26B, Mir-9 and Mir-451 regulate genes involved in inflammation. Mir-126, Mir-130 and Mir-520H have been shown play role in angiogenesis. RT-PCR validated the expression of Mir-9, Mir-451, Mir-126, and Mir-130a in these patients.
Conclusions: :
Dry AMD is associated with altered gene expression of microRNA in peripheral blood monocytes, thereby supporting our hypothesis. Systemic immune responses may be involved in the pathogenesis and progression of Dry AMD. Furthermore, the identified microRNAs species may correlate with prognosis or serve as future therapeutic targets.
Keywords: age-related macular degeneration • gene microarray • immunomodulation/immunoregulation