Lack of association of the CD14/C-159T polymorphism with susceptibility and serological activity parameters of rheumatoid arthritis

Sexual Dimorphic Role of CD14 (Cluster of Differentiation 14) in Salt-Sensitive Hypertension and Renal Injury

Genomic sequence and gene expression association studies in animals and humans have identified genes that may be integral in the pathogenesis of various diseases. CD14 (cluster of differentiation 14)-a cell surface protein involved in innate immune system activation-is one such gene associated with cardiovascular and hypertensive disease. We previously showed that this gene is upregulated in renal macrophages of Dahl salt-sensitive animals fed a high-salt diet; here we test the hypothesis that CD14 contributes to the elevated pressure and renal injury observed in salt-sensitive hypertension. Using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9), we created a targeted mutation in the CD14 gene on the Dahl SS (SS/JrHSDMcwi) background and validated the absence of CD14 peptides via mass spectrometry. Radiotelemetry was used to monitor blood pressure in wild-type and CD14^-/- animals challenged with high salt and identified infiltrating renal immune cells via flow cytometry. Germline knockout of CD14 exacerbated salt-sensitive hypertension and renal injury in female animals but not males. CD14^-/- females demonstrated increased infiltrating macrophages but no difference in infiltrating lymphocytes. Transplant of CD14^+/+ or CD14^-/- bone marrow was used to isolate the effects of CD14 knockout to hematopoietic cells and confirmed that the differential phenotype observed was due to knockout of CD14 in hematopoietic cells. Ovariectomy was used to remove the influence of female sex hormones, which completely abrogated the effect of CD14 knockout. These studies provide a novel treatment target and evidence of a new dichotomy in immune activation between sexes within the context of hypertensive disease where CD14 regulates immune cell activation and renal injury.

Polymorphisms of Toll-like receptor-4 and CD14 in systemic lupus erythematosus and rheumatoid arthritis

Background

Toll-like receptor 4 (TLR4) and its co-receptor CD14 play a major role in innate immunity by recognizing PAMPs and signal the activation of adaptive responses. These receptors can recognize endogenous ligands mainly auto-antigens. In addition, TLR4 (Asp299Gly) and CD14 (C/T -159) polymorphisms (SNPs) may modify qualitatively and/or quantitatively their expression. Therefore, they could be implied in autoimmune diseases and can influence both susceptibility and severity of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

Patients and methods

TLR4 (Asp299Gly) and CD14 (C/T -159) SNPs were genotyped using polymerase chain reaction (PCR)-RFLP in 127 SLE patients, 100 RA patients, and 114 healthy controls matched in age and gender.

Results

CD14*T allele was significantly more frequent in SLE patients (0.456) comparatively to controls (0.355), p = 0.02 OR (95% CI) = 1.53 [1.04-2.24]. In RA patients, the higher frequency of CD14*T allele (0.405) failed to reach significance, p = 0.28. Investigation of the TLR4 (Asp299Gly) SNP showed no significant association neither with SLE nor with RA.

Analysis of these SNPs according to clinical and biological features showed a significant higher frequency of arthritis in SLE patients carrying CD14*T/T genotype (92%) comparatively to those with C/C and C/T genotypes (72.5%), p = 0.04. Moreover, SLE patients carrying CD14*T/T/TLR4*A/A haplotype had significantly more arthritis (91.3%) than the rest of SLE group (73%), p = 0,044 and confirmed by multivariable analysis after adjustment according to age and gender, p = 0.01.

Conclusion

The CD14 (-159)*T allele seems to be associated with susceptibility to SLE and arthritis occurrence.

The association with the -159C/T polymorphism in the promoter region of the CD14 gene and juvenile idiopathic arthritis in a Chinese Han population

OBJECTIVE

Juvenile idiopathic arthritis (JIA) is generally considered to be caused by interaction of genetic and environmental factors. We investigated the association of a C-to-T transition in the promoter region of the CD14 gene on chromosome 5q31.1 and JIA in a Chinese Han population.

METHODS

One hundred sixty-three children with JIA and 281 healthy children (age- and sex-matched to JIA group) were studied. Polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) was used for analysis of the genotypes. (Trial registration number ChiCTR-CCC-00000312.)

RESULTS

CD14 promoter-159 genotype frequencies of CC, CT, and TT were 11.48%, 49.18%, and 39.34%, respectively, in the systemic onset JIA group; 21.62%, 43.24%, and 35.14%, in the polyarticular JIA group; 16.67%, 50%, and 33.33%, in the oligoarticular JIA group; 6.9%, 75.86%, and 17.24%, in the group with other types of JIA; and 37.01%, 46.98%, and 16.01%, in the control group. Genotype frequency and allele frequency distribution were in accord with Hardy-Weinberg equilibrium. There were statistically significant differences in frequencies of genotype and allele in CD14 C-159T polymorphism between JIA group and control group (genotype: chi-squared = 33.168, p < 0.05, CT vs CC, OR 2.946, 95% CI 1.739-4.990; TT vs CC, OR 5.426, 95% CI 2.977-9.891. Allele: chi-squared = 33.168, p < 0.05, T vs C, OR 2.251, 95% CI 1.704-2.973). The T allele frequencies of boys and girls were significantly higher than those in the control group (p < 0.001 of both).

CONCLUSION

CD14 gene promoter C-159T polymorphism is significantly correlated with JIA in the Chinese Han population. The T allele of the C-159T polymorphism of CD14 gene may be a genetic risk factor for JIA.

CD14, endotoxin, and asthma risk: actions and interactions

A functional single nucleotide polymorphism in the 5 genomic region of CD14 (CD14/-159) is one of the most widely tested genetic variations in relation to asthma and associated traits. The results of these studies have shown a remarkable, statistically significant heterogeneity, with some studies indicating the T-allele as a risk factor, others the C-allele, and others finding no association. Recent studies in which exposure to house-dust endotoxin or to domestic sources of microbial exposure were assessed concomitantly with CD14/-159 have shown a consistent, replicable gene-environment interaction. Specifically, results suggest that the C-allele is a risk factor for allergic phenotypes at low levels of exposure, whereas the T-allele is a risk factor at high levels of exposure. This finding seems to be explained by a genetically-determined heterogeneity for the protective effect of microbial exposure on allergic phenotypes, with homozygotes for the C-allele showing a much stronger negative association between exposure and allergic outcomes than carries of the other two genotypes. These results suggest that the often encountered, limited replicability of genetic associations may, at least in part, be due to complex interactions between genes and environment in determining asthma-related outcomes.

Is the CD14 C159T polymorphism effective in the development of secondary amyloidosis in Familial Mediterranean fever?

The most important complication of FMF is the development of amyloidosis. It is more common in the eastern Mediterranean compared to the US. The individual response to endotoxin may have a significant effect on the development of amyloidosis in FMF patients. To investigate the association between CD14 promotor C-159T polymorphism and development of amyloidosis, one hundred and forty-six patients who had FMF and had not developed amyloidosis; 26 with FMF and secondary amyloidosis and 92 controls were genotyped at the CD14-C159T locus. There was no difference between the genotype distribution of FMF patients (CC 30.0%, CT 50.0%, TT 20.0%) and controls (CC 29.2%, CT 45.8%, TT 25%); or between FMF patients with amyloidosis (CC 30.8%, CT 53.8%, TT 15.4%) or without amyloidosis (CC 29.2%, CT 45.8%, TT 25%). Our study shows that the CD14-C159T polymorphism is not associated with FMF or development of amyloidosis in the population studied. The effect of the genetic variations in the endotoxin signaling pathway under different environmental conditions such as high and low endotoxin exposure remain to be determined.