Resequencing of the CCL5 and CCR5 genes and investigation of variants for association with diabetic nephropathy

Abstract

Chemokine (C-C motif) ligand 5 (CCL5) and chemokine (C-C motif) receptor 5 are implicated in the pathogenesis of diabetic nephropathy (DN). We hypothesize that variants in these genes may be associated with DN. The CCL5 and chemokine receptor type 5 (CCR5) genes were resequenced, variants identified (n¼58), allele frequencies determined in 46 individuals (92 chromosomes) and efficient haplotype tag single-nucleotide polymorphisms (htSNPs) selected to effectively evaluate the common variation in these genes. One reportedly functional gene variant and eight htSNPs were genotyped in a case-control association study involving Caucasian individuals with type 1 diabetes (267 cases with DN and 442 non-nephropathic diabetic controls). Genotyping was performed using MassARRAY iPLEX, TaqMan, gel electrophoresis and direct capillary sequencing. After correction for multiple testing, there were no statistically significant associations between variants in the CCL5 and CCR5 genes and DN. Keywords: association; chemokine; CCL5; CCR5; diabetic nephropathy; resequencing Diabetic nephropathy (DN) is the leading cause of end-stage renal disease in the Western world 1 with significant evidence that a subset of type 1 diabetic patients are genetically predisposed to developing DN. 2 Chemokine (C-C motif) ligand 5 (alternatively known as regulated upon activation, normal T cell expressed and secreted; CCL5) and its cognate receptor, chemokine receptor type 5 (CCR5), are biological candidate genes for DN.CCL5 is a potent chemoattractant produced by renal mesangial cells, which is active in the recruitment of monocytes and macrophages into the glomeruli and interstitium. CCL5 is nuclear factor -kB dependent and is upregulated by proteinuria 3 and other factors associated with the diabetic milieu. 4-6 Blockade of CCR5 has been shown to substantially reduce monocyte infiltration in experimental glomerulonephritis. 7 CCL5 and CCR5 have received considerable attention as candidate genes for DN, although these studies have focused on selected variants with inconsistent findings. [8][9][10][11][12][13][14][15] The CCL5 gene locus has been assigned to 17q11.2-q12, 16 and the CCR5 gene is located on chromosome 3p21. 17 Coding regions, intron-exon boundaries, untranslated and flanking regions of the CCL5 and CCR5 genes have been comprehensively screened to identify polymorphisms, and a robust case-control study was performed to assess the association between common haplotype tagging or functional variants and DN in a Caucasian population with type 1 diabetes.The Irish case-control collection investigated in this paper has been described previously. 18 Briefly, cases have type 1 diabetes with DN, while controls are type 1 diabetic patients without nephropathy. The average age at recruitment of cases and controls was 48.7 (s.d. 9.6) years and 42.2 (s.d. 11.7) years, respectively, with an average disease duration of 32.0 (s.d. 9.6) years for cases and 27.2 (s.d. 9.3) years for controls.

Association of chemokine ligand 5/chemokine receptor 5 gene promoter polymorphisms with diabetic microvascular complications: A meta‐analysis

“…Some researchers have shown that the CCL5 and CCR5 genes variants could be susceptibility factors for DMI 1,[10][11][12][13][14][15][16] . Yet, the results have not been verified in other studies 3,9,17 . The primary aim of the present study was to derive a more precise evaluation of the associations between the CCL5/CCR5 genes variants and the risk of DMI.…”

“…The heterogeneity disappeared ( I 2 = 0%) after excluding these studies. The trials published by Pettigrew et al ,. Mlynarski et al .…”

“…These patients might have genetic risk factors associated with DMI. In addition, DMI can be considered as a cytokine‐associated innate immune response, and downregulation of specific cytokines could reduce the incidence of DMI. Identification of cytokines with higher risks will be useful for early preventive care of DMI.…”

“…The risk factors of DMI include hyperglycemia, hypertension and genetic factors. Although hypoglycemic and antihypertensive Chemokine ligand 5 (CCL5), also known as regulated on activation normal T expressed and secreted (RANTES), is a member of the C-C chemokine family, and is mainly expressed on CD8 + T cells 3 . Chemokine ligand 5 has the ability to recruit, activate and costimulate T cells, and thus mediate innate and adaptive immune responses 5 .…”

Effects of CCR5 59029G/A polymorphism on the risk to diabetic nephropathy

“…Among them, 3 were in Caucasian populations while the others were in Asian populations. Additionally, the quality assessment of these studies based on NOS showed that only the article of Pettigrew [ 28 ] had the relative poor quality with 4 scores and the quality the other included studies was good. Table 1 summarized the essential information of all included studies.…”