SNPs involved in AMD



Role of MCP-1 and Its Receptor in Age Related Macular Degeneration: Single Nucleotide Polymorphisms Study

 

 

Age related macular degeneration is an eye disorder which leads to irreversible blindness in aged.  Various studies have been carried out to screen the role of different biomolecules in disease progression. MCP-1, while acting in concert with receptor CCR2,  have been found to promote recruitment of macrophages but the mechanism how these cytokines are regulated  in the eye of patients with AMD remain unclear. In our previous studies we have found that CCL2 deficient mice have characteristics of AMD disease. We hypothesized that any dysfunction in the CCL2 and CCR2 results in impaired macrophage recruitment and debris formation under the retinal pigment epithelium (RPE) contributions to AMD. Patients with AMD and normal controls were included in study. The absence of any genetic association studies between CCL2 or CCR2 and AMD from Indian patients prompted us to explore the role of these chemokines in Indian patients.

Total protein estimation was carried out using Bradford assay and the expression of CCL2 was analyzed using enzyme linked immunosorbant assay. Flow cytometry was employed to study the expression levels of surface receptors namely hCCR2 in PBMCs and SNP (Single nucleotide polymorphism) was analyzed by using real time PCR. We analyzed the association between single nucleotide polymorphisms (SNPs) of CCL2 (rs4586) and CCR2 (rs1799865) with their respective protein levels. Our results revealed that individuals possessing both SNPs are at a higher risk of development of AMD. The genotype and allele frequency for both CCL2 and CCR2 was found to be significantly different between AMD and normal controls and it was found that TT genotype was more frequent in AMD patients than in controls for both CCL2 and CCR2. ELISA estimation revealed elevated levels of serum CCL2 in AMD patients as compared to normal controls. No difference was observed in CCL2 levels for wet and dry AMD.  CCL2 concentration was significantly elevated in the patients affected in one or both eyes with AMD as compare to controls However, flow cytometry analysis of PBMCs of AMD patients and normal controls indicates a significant decrease in proportion of CCR2 expressing PBMCs from AMD patients than those from normal controls. This lead to conclusion that  elevated level of CCL2 and low level of CCR2 results in   inflammation caused by extravasations of activated monocytes/lymphocytes at the site of macular degeneration

Anand A, Sharma NK, Gupta A, Prabhakar S, Sharma SK, et al. (2012) Single Nucleotide Polymorphisms in MCP-1 and Its Receptor Are Associated with the Risk of Age Related Macular Degeneration. PLoS ONE 7(11): e49905.

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