Association of the -2510A/G chemokine (C-C motif) ligand 2 polymorphism with knee osteoarthritis in a Korean population

Association of CCL2 Gene Variants with Osteoarthritis

BACKGROUND AND AIMS

The chemokine (C-C motif) Ligand 2 (CCL2)/CCR2 signaling was associated with macrophage accumulation, synovitis and cartilage damage in a mouse osteoarthritis (OA) model.

MATERIALS AND METHODS

Here a case-control study in a Chinese Han population was conducted to investigate the possible association between the CCL2 gene polymorphism and risk of OA. DNA was extracted from 367 primary knee OA patients and 303 healthy controls. Then CCL2 gene polymorphisms were determined using a standard polymerase chain reaction restriction fragment length polymorphism. Plasma CCL2 levels were measured by using sandwich enzyme-linked immunosorbent assay (ELISA).

RESULTS

It was found the CCL2 gene rs1024611 and rs4586 polymorphisms significantly increased the risk of OA. Stratified analyses showed the risk of OA might be increased by rs1024611 polymorphism in males and non-drinkers, and was increased by rs4586 polymorphism among smokers and drinkers. The CC genotype of rs4586 polymorphism was significantly correlated with the increased CCL2 level compared to TT genotype.

CONCLUSIONS

In conclusion, CCL2 gene polymorphisms (rs1024611 and rs4586) confer susceptibility to OA and may be potential markers for early diagnosis of OA.

The genetics behind osteoarthritis: Asian focus

Osteoarthritis (OA), a degenerative joint disease, is the most common form of arthritis in the elderly. Problems arising from the condition are not only health, physical, and psychological, but also economical and social. OA is a complex disease causes by environmental factors (obesity, female gender, advancing age) and genetics. A strong genetic contribution to primary OA has been observed in several studies. Asian population is undoubtedly genetically different from European, whom most studies have been performed. This review systematically compares results of molecules involved with OA from studies performed on Asian and Caucasian populations. The clear differences between Asian and Caucasian populations may be from the sex- and ethnic-specific nature of the disease, as well as from the inclusion criteria of the studies. Global collaboration is highly significant in understanding genetic underlying OA. Knowledge gained from genetic study is important to the development of prevention and therapeutic intervention, and to identify individuals at risk of developing severe or progressive OA.

Association between CCL2 haplotypes and knee osteoarthritis

We examined five single nucleotide polymorphisms (SNPs) and reconstructed 5-locus haplotypes of the CCL2 gene, in knee osteoarthritis (OA) cases and in controls. The CCL2 rs2857657 variant (G) allele was observed more frequently in female knee OA cases than in controls. One haplotype (H5) was observed exclusively in the control group (f = 2.3%). Genetic variation in the CCL2 gene may be associated with knee OA.

MCP1 haplotypes associated with protection from pulmonary tuberculosis

Background

The monocyte chemoattractant protein 1 (MCP-1) is involved in the recruitment of lymphocytes and monocytes and their migration to sites of injury and cellular immune reactions. In a Ghanaian tuberculosis (TB) case-control study group, associations of the MCP1 -362C and the MCP1 -2581G alleles with resistance to TB were recently described. The latter association was in contrast to genetic effects previously described in study groups originating from Mexico, Korea, Peru and Zambia. This inconsistency prompted us to further investigate the MCP1 gene in order to determine causal variants or haplotypes genetically and functionally.

Results

A 14 base-pair deletion in the first MCP1 intron, int1del554-567, was strongly associated with protection against pulmonary TB (OR = 0.84, CI 0.77-0.92, P_corrected = 0.00098). Compared to the wildtype combination, a haplotype comprising the -2581G and -362C promoter variants and the intronic deletion conferred an even stronger protection than did the -362C variant alone (OR = 0.78, CI 0.69-0.87, P_nominal = 0.00002; adjusted P_global = 0.0028). In a luciferase reporter gene assay, a significant reduction of luciferase gene expression was observed in the two constructs carrying the MCP1 mutations -2581 A or G plus the combination -362C and int1del554-567 compared to the wildtype haplotype (P = 0.02 and P = 0.006). The associated variants, in particular the haplotypes composed of these latter variants, result in decreased MCP-1 expression and a decreased risk of pulmonary TB.

Conclusions

In addition to the results of the previous study of the Ghanaian TB case-control sample, we have now identified the haplotype combination -2581G/-362C/int1del554-567 that mediates considerably stronger protection than does the MCP1 -362C allele alone (OR = 0.78, CI 0.69-0.87 vs OR = 0.83, CI 0.76-0.91). Our findings in both the genetic analysis and the reporter gene study further indicate a largely negligible role of the variant at position -2581 in the Ghanaian population studied.

Chemokine (C-C motif) ligand 2 (CCL2) in sera of patients with type 1 diabetes and diabetic complications

Background

Chemokine (C-C motif) ligand 2 (CCL2), commonly known as monocyte chemoattractant protein-1 (MCP-1), has been implicated in the pathogenesis of many diseases characterized by monocytic infiltration. However, limited data have been reported on MCP-1 in type 1 diabetes (T1D) and the findings are inconclusive and inconsistent.

Methods

In this study, MCP-1 was measured in the sera from 2,472 T1D patients and 2,654 healthy controls using a Luminex assay. The rs1024611 SNP in the promoter region of MCP-1 was genotyped for a subset of subjects (1764 T1D patients and 1323 controls) using the TaqMan-assay.

Results

Subject age, sex or genotypes of MCP-1 rs1024611SNP did not have a major impact on serum MCP-1 levels in either healthy controls or patients. While hemoglobin A1c levels did not have a major influence on serum MCP-1 levels, the mean serum MCP-1 levels are significantly higher in patients with multiple complications (mean = 242 ng/ml) compared to patients without any complications (mean = 201 ng/ml) (p = 3.5×10⁻⁶). Furthermore, mean serum MCP-1 is higher in controls (mean = 261 ng/ml) than T1D patients (mean = 208 ng/ml) (p<10⁻²³). More importantly, the frequency of subjects with extremely high levels (>99^th percentile of patients or 955 ng/ml) of serum MCP-1 is significantly lower in the T1D group compared to the control group (odds ratio = 0.11, p<10⁻³³).

Conclusion

MCP-1 may have a dual role in T1D and its complications. While very high levels of serum MCP-1 may be protective against the development of T1D, complications are associated with higher serum MCP-1 levels within the T1D group.

Heritability estimates and linkage analysis of 23 short tandem repeat loci on chromosomes 2, 11, and 12 in an endemic osteochondropathy in China

OBJECTIVE

To estimate the heritability of Kashin-Beck disease (KBD) in first-degree relatives and to identify chromosome regions likely to contain susceptibility loci for KBD.

METHODS

A total of 331 probands with confirmed KBD in their pedigrees were selected from 9331 residents in 17 KBD villages of Linyou county, northwestern China. The heritability (h(2)) in first-degree relatives was estimated by using Falconer's formula. The segregation ratio was calculated by the Li-Mantel-Gart method. A total of 23 short tandem repeat (STR) loci on chromosomes 2, 11, and 12 were used to identify the susceptibility genes for KBD by linkage analysis using the GENEHUNTER program in 19 KBD pedigrees.

RESULTS

The general prevalence rate of KBD was 13.75% in the 17 KBD villages, lower than that of 20.88% in the first-degree relatives of the KBD probands. In the first-degree relatives, the heritability was 0.064 and the segregation ratio 35.10% (p < 0.05). Slight evidence for heritability was detected only in locus D12S1725 with a logarithm of odds (LOD) score of 1.95. However, the nonparametric linkage (NPL) scores showed no linkage between KBD and the 23 loci; the maximum NPL score was 1.59 for locus D12S1725.

CONCLUSIONS

Our results show that 35.10% of the heritability is attributable to genetic variation for the KBD phenotype among individuals of Linyou county, and the segregation ratio supports a multifactorial inheritance of KBD. There is no significant linkage between KBD and the 23 markers in the Linyou population examined; however, markers near the locus D12S1725 may indicate loci for further study.