Genetic control of CCL24, POR, and IL23R contributes to the pathogenesis of sarcoidosis.

Sarcoidosis is a genetically complex systemic inflammatory disease that affects multiple organs. We present a GWAS of a Japanese cohort (700 sarcoidosis cases and 886 controls) with replication in independent samples from Japan (931 cases and 1,042 controls) and the Czech Republic (265 cases and 264 controls). We identified three loci outside the HLA complex, CCL24, STYXL1-SRRM3, and C1orf141-IL23R, which showed genome-wide significant associations (P < 5.0 × 10-8) with sarcoidosis; CCL24 and STYXL1-SRRM3 were novel. The disease-risk alleles in CCL24 and IL23R were associated with reduced CCL24 and IL23R expression, respectively. The disease-risk allele in STYXL1-SRRM3 was associated with elevated POR expression. These results suggest that genetic control of CCL24, POR, and IL23R expression contribute to the pathogenesis of sarcoidosis. We speculate that the CCL24 risk allele might be involved in a polarized Th1 response in sarcoidosis, and that POR and IL23R risk alleles may lead to diminished host defense against sarcoidosis pathogens.

Genetic characterization and susceptibility for sarcoidosis in Japanese patients: risk factors of BTNL2 gene polymorphisms and HLA class II alleles.

PURPOSE: Sarcoidosis is a heterogeneous and multisystem granulomatous disorder. The etiology still is uncertain, but the disease currently is thought to be triggered by various genetic as well as environmental factors. Recently, an association between sarcoidosis and the butyrophilin-like 2 (BTNL2) gene located in close proximity to the HLA-DRB1 gene was reported. The purpose of our study was to verify the relationship between BTNL2 and HLA risk alleles for the susceptibility to sarcoidosis, and to assess whether the BTNL2 association is independent of the HLA risk alleles. METHODS: In our study, 11 single nucleotide polymorphisms (rs28362677, rs2076533, rs2076530, rs2076529, rs2294881, rs3763304, rs2076523, rs28362682, rs3806156, rs9268499, rs3763317), including the functional rs2076530 (G > A) of the BTNL2 gene, and HLA-DRB1 and -DQB1 alleles, were genotyped in 237 Japanese patients diagnosed with sarcoidosis and 287 healthy Japanese control subjects. RESULTS: In the patient group, the HLA-DRB1*08:03 (P = 6.15 × 10(-5), odds ratio [OR] = 2.43) and BTNL2 rs2076530_A (P = 6.90 × 10(-6), OR = 1.84) were associated with disease susceptibility. Upon stratification analysis in search for a synergistic effect given the extensive linkage disequilibrium between BTNL2 rs2076530_A and HLA-DRB1*08:03, our results suggested that the risk-bearing allele of these two loci interact negatively. No significant differences were observed in allele frequencies for alleles in patients with ocular and other systemic sarcoidosis. CONCLUSIONS: Our studies implicated that the HLA-DRB1 allele is a major contributing genetic factor in the development of sarcoidosis in Japan. However, further studies are needed to verify how HLA or BTNL2 alleles confer the disease phenotype, severity of sarcoidosis.

Lack of association between IL10 polymorphisms and sarcoidosis in Japanese patients.

PURPOSE: To investigate whether interleukin 10 (IL10) gene polymorphisms are associated with the development of sarcoidosis in Japanese patients. METHODS: Two hundred and eighty-eight Japanese sarcoidosis patients and 310 Japanese healthy controls were recruited. We genotyped 9 single-nucleotide polymorphisms in IL10 and assessed the allelic diversity between cases and controls. RESULTS: No significant differences in the frequency of IL10 alleles, genotypes, and haplotypes in the sarcoidosis cases compared to the controls were detected. CONCLUSIONS: Our results suggest that IL10 polymorphisms are not significantly related to the pathogenesis of sarcoidosis in the Japanese population.

Functional processing of nuclear Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP-N): evidence for a critical role of proteolytic processing in the regulation of its catalytic activity, subcellular localization and substrate targeting in vivo.

Ca(2+)/calmodulin-dependent protein kinase phosphatase (CaMKP) and its nuclear homolog CaMKP-N are Ser/Thr protein phosphatases that belong to the PPM family. These phosphatases are highly specific for multifunctional CaM kinases and negatively regulate their activities. CaMKP-N is only expressed in the brain and specifically localized in the nucleus. In this study, we found that zebrafish CaMKP-N (zCaMKP-N) underwent proteolytic processing in both the zebrafish brain and Neuro2a cells. In Neuro2a cells, the proteolytic processing was effectively inhibited by the proteasome inhibitors MG-132, Epoxomicin, and Lactacystin, suggesting that the ubiquitin-proteasome pathway was involved in this processing. Using MG-132, we found that the proteolytic processing changed the subcellular localization of zCaMKP-N from the nucleus to the cytosol. Accompanying this change, the cellular targets of zCaMKP-N in Neuro2a cells were significantly altered. Furthermore, we obtained evidence that the zCaMKP-N activity was markedly activated when the C-terminal domain was removed by the processing. Thus, the proteolytic processing of zCaMKP-N at the C-terminal region regulates its catalytic activity, subcellular localization and substrate targeting in vivo.

Toll-like receptor 2 (TLR2) gene polymorphisms are not associated with sarcoidosis in the Japanese population.

PURPOSE: Sarcoidosis is a systemic inflammatory disease characterized by the formation of non-caseating granulomas, with varied clinical manifestations. The common etiology of sarcoidosis is uncertain, but it is thought to be triggered by an exogenous antigenic stimulus, such as some bacterial proteins. Toll-like receptors (TLRs) recognize microbial components and elicit innate as well as adaptive immune responses. It has been reported that polymorphisms in TLR2 might be important in a small group of Caucasian sarcoidosis patients. The present study aimed to establish whether these findings are relevant to the Japanese population. METHODS: We genotyped 5 single-nucleotide polymorphisms (SNPs) in TLR2 and assessed the allelic diversity between 257 Japanese sarcoidosis patients and 193 Japanese healthy controls. RESULTS: No significant differences in the frequency of TLR2 alleles and haplotypes in the sarcoidosis cases were found in comparison with the controls. However, marginal associations were observed for TLR2 at rs3804099 and rs3804100 in sarcoidosis patients with cutaneous manifestations. CONCLUSIONS: Our results suggest that TLR2 polymorphisms are not significantly related to the pathogenesis of sarcoidosis in the Japanese population.

Lack of association between toll-like receptor 4 gene polymorphisms and sarcoidosis-related uveitis in Japan.

PURPOSE: Toll-like receptors (TLRs) are pattern-recognition receptors that play an important role in innate and adaptive immune responses to microbial pathogens. Among TLRs, TLR4 recognizes lipopolysaccharides of Gram-negative bacteria. Genetic polymorphisms within the TLR4 gene have been reported to be associated with various inflammatory diseases; therefore, TLR4 appears to be a susceptibility gene for sarcoidosis. Although sarcoidosis has various clinical manifestations, its association with uveitis is more common in Japan than in other countries. The aim of this study was to investigate whether TLR4 polymorphisms were associated with sarcoidosis-related uveitis in a Japanese population. METHODS: Two hundred twenty-three patients with sarcoidosis and 206 healthy control subjects were recruited at seven sites in Japan. Eight single-nucleotide polymorphisms (SNPs) in TLR4 were genotyped with a TaqMan assay, and allelic and phenotypic diversity were assessed in affected and control subjects. RESULTS: We found no association with susceptibility to sarcoid-related uveitis for any of the SNPs analyzed. Strong linkage disequilibrium was observed among all the SNPs analyzed (D'>/=0.78), which were located in one haplotype block. CONCLUSION: TLR4 polymorphisms do not play an important role in the development of uveitis in Japanese patients with sarcoidosis.

Phenotype-genotype analysis of CYP1A2 in Japanese patients receiving oral theophylline therapy.

OBJECTIVE: To clarify the association between the cytochrome P450 (CYP) 1A2 genotype with the CYP1A2 phenotype and to search for the CYP1A2*1K haplotype, which has been shown to decrease CYP1A2 inducibility and/or other functional polymorphisms in Japanese. METHODS: Two polymorphisms, CYP1A2*1C and CYP1A2*1F, were genotyped in 126 patients receiving oral slow-release theophylline (TP) therapy and in 224 healthy volunteers. The CYP1A2 phenotype was assessed by the plasma [1-methyluric acid (1U)+3-methylxanthine (3X)]/TP ratio in the patients. The volunteers were given 150 mg caffeine, and the urine [1X+1U+5-acetylamino-6-amino-3-methyluracil (AAMU)]/17U ratio was used for CYP1A2 phenotyping. CYP1A2 intron 1 and six exons (exon 2-exon 7) were sequenced in the patients whose (1U+3X)/TP ratios were below the mean-2SD of those of all patients, and intron 1 was also sequenced in an additional 20 healthy volunteers exhibiting putative low CYP1A2 activities. RESULTS: The individual (1U+3X)/TP ratios ranged from 0.007 to 0.21 (a 30-fold difference) in the patients, and the (1X+1U+AAMU)/17U ratios ranged from 1.6 to 112 (a 70-fold difference) in the healthy volunteers. The CYP1A2 activities were not significantly influenced by CYP1A2*1C or CYP1A2*1F. We found no functional polymorphisms by a sequencing analysis. CONCLUSION: These results suggest that the CYP1A2*1C and CYP1A2*1F genotypes are not crucial factors for the variability of CYP1A2 activity and that the CYP1A2*1K haplotype is either nil or only shows a very low frequency in Japanese.