Association of toll-like receptor 5 gene polymorphism with susceptibility to ossification of the posterior longitudinal ligament of the spine in korean population

Evaluation of Genetic and Nongenetic Risk Factors for Degenerative Cervical Myelopathy

STUDY DESIGN

Cohort study.

OBJECTIVE

We aimed to evaluate the associations of genetic and nongenetic factors with degenerative cervical myelopathy (DCM).

SUMMARY OF BACKGROUND DATA

There is mounting evidence for an inherited predisposition for DCM, but uncertainty remains regarding specific genetic markers involved. Similarly, nongenetic factors are thought to play a role.

MATERIALS AND METHODS

Using diagnosis codes from hospital records linked to the UK Biobank cohort, patients with cervical spondylosis were identified followed by the identification of a subset with DCM. Nongenetic variables evaluated included age, sex, race, Townsend deprivation index, body mass index, occupational demands, osteoporosis, and smoking. Genome-wide association analyses were conducted using logistic regression adjusted for age, sex, population principal components, and follow-up.

RESULTS

A total of 851 DCM cases out of 2787 cervical spondylosis patients were identified. Several nongenetic factors were independently associated with DCM including age [odds ratio (OR)=1.11, 95% CI=1.01-1.21, P =0.024], male sex (OR=1.63, 95% CI=1.37-1.93, P <0.001), and relative socioeconomic deprivation (OR=1.03, 95% CI=1.00-1.06, P =0.030). Asian race was associated with lower DCM risk (OR=0.44, 95% CI=0.22-0.85, P =0.014). We did not identify genome-wide significant (≤5×10 -8 ) single-nucleotide polymorphisms (SNPs) associated with DCM. The strongest genome-wide signals were at SNP rs67256809 in the intergenic region of the genes LINC02582 and FBXO15 on chromosome 18 ( P =1.12×10 -7 ) and rs577081672 in the GTPBP1 gene on chromosome 22 ( P =2.9×10 -7 ). No SNPs reported in prior DCM studies were significant after adjusting for replication attempts.

CONCLUSIONS

Increasing age, male sex, and relative socioeconomic deprivation were identified as independent risk factors for DCM, whereas Asian race was inversely associated. SNPs of potential interest were identified in GTPBP1 and an intergenic region on chromosome 18, but these associations did not reach genome-wide significance. Identification of genetic and nongenetic DCM susceptibility markers may guide understanding of DCM disease processes, inform risk, guide prevention and potentially inform surgical outcomes.

LEVEL OF EVIDENCE

Prognostic level III.

Genetics of Degenerative Cervical Myelopathy: A Systematic Review and Meta-Analysis of Candidate Gene Studies

Degenerative cervical myelopathy (DCM) is estimated to be the most common cause of adult spinal cord impairment. Evidence that is suggestive of a genetic basis to DCM has been increasing over the last decade. A systematic search was conducted in MEDLINE, EMBASE, Cochrane, and HuGENet databases from their origin up to 14th December 2019 to evaluate the role of single genes in DCM in its onset, clinical phenotype, and response to surgical intervention. The initial search yielded 914 articles, with 39 articles being identified as eligible after screening. We distinguish between those contributing to spinal column deterioration and those contributing to spinal cord deterioration in assessing the evidence of genetic contributions to DCM. Evidence regarding a total of 28 candidate genes was identified. Of these, 22 were found to have an effect on the radiological onset of spinal column disease, while 12 genes had an effect on clinical onset of spinal cord disease. Polymorphisms of eight genes were found to have an effect on the radiological severity of DCM, while three genes had an effect on clinical severity. Polymorphisms of six genes were found to have an effect on clinical response to surgery in spinal cord disease. There are clear genetic effects on the development of spinal pathology, the central nervous system (CNS) response to bony pathology, the severity of both bony and cord pathology, and the subsequent response to surgical intervention. Work to disentangle the mechanisms by which the genes that are reviewed here exert their effects, as well as improved quality of evidence across diverse populations is required for further investigating the genetic contribution to DCM.

The COL6A1 rs201153092 single nucleotide polymorphism, associates with thoracic ossification of the posterior longitudinal ligament

Thoracic ossification of the posterior longitudinal ligament (T-OPLL) is one of the most common factors that causes thoracic spinal stenosis, resulting in intractable myelopathy and radiculopathy. Our previous study reported that the rs201153092 polymorphism present in the collagen 6A1 (COL6A1) gene was a potentially pathogenic locus for the development of T-OPLL. The present study aimed to determine whether the rs201153092 mutation causes abnormal expression of COL6A1 in Han Chinese patients with T-OPLL, and to examine the effects of this mutation on osteogenesis by establishing a model of osteogenic differentiation. COL6A1 gene mutant and wild-type mouse 3T3-E1 embryonic osteoblast models were constructed to induce the differentiation of these cells into osteoblasts. The potential of the mutation site to induce abnormal expression of the COL6A1 gene and osteogenic markers was assessed via reverse transcription-quantitative PCR and western blot analyses. The results demonstrated that the rs201153092A mutation site resulted in significantly increased COL6A1 gene expression levels in the OPLL tissues obtained following clinical surgery. This mutation was shown to play an important role in the development of T-OPLL by regulating the overexpression of the COL6A1 gene and significantly increasing the expression levels of osteogenic markers. The findings of the present study suggested that the rs201153092A mutant variant could increase the expression levels of COL6A1 and consequently play a role in the pathogenesis of T-OPLL.

Potential role of the IL17RC gene in the thoracic ossification of the posterior longitudinal ligament

The thoracic ossification of the posterior longitudinal ligament (T-OPLL) can cause thoracic spinal stenosis, which results in intractable myelopathy and radiculopathy. Our previous whole-genome sequencing study first reported rs199772854 in the interleukin 17 receptor C (IL17RC) gene as a potentially pathogenic loci for T-OPLL. The aim of the present study was to examine the effects of the IL17RC gene rs199772854A site mutation on osteogenesis by establishing a model of osteogenic differentiation. IL17RC gene mutation site and wild-type site mouse embryonic osteoblast (3T3-E1) models were constructed in order to induce the differentiation of the cells into osteoblasts. Whether the mutation site causes the abnormal expression of the IL17RC gene and osteogenic markers was analyzed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The IL17RC gene rs199772854A site mutation was demonstrated to play a biological role through the overexpression of its own gene, and also to significantly increase the expression levels of osteogenic markers. Furthermore, the mutation upregulated the expression of the key proteins, tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) and nuclear factor (NF)-κB, in the interleukin (IL)-17 signaling axis. On the whole, the findings of this study suggest that the IL17RC gene rs199772854A loci mutation propels mouse embryonic osteoblasts towards osteogenic differentiation and may play an important role in the pathogenesis of T-OPLL. The IL17RC gene may promote osteogenesis through the IL-17 signaling pathway and may thus be involved in the process of ectopic osteogenesis in T-OPLL.

Association of IL17RC and COL6A1 genetic polymorphisms with susceptibility to ossification of the thoracic posterior longitudinal ligament in Chinese patients

Background

In our previous whole-genome sequencing study of 30 unrelated northern Chinese Han patients, we identified six single nucleotide polymorphisms (SNPs) in the interleukin 17 receptor C (IL17RC) and collagen type VI α1 chain (COL6A1) genes that were potentially associated with thoracic ossification of the posterior longitudinal ligament (T-OPLL). To determine whether these six SNPs are associated with susceptibility to T-OPLL in the northern Chinese Han population, we performed a case-control association study to confirm specific susceptible loci in the expanded samples.

Methods

The six SNPs in the IL17RC and COL6A1 genes were analyzed in 200 northern Chinese individuals (100 patients and 100 control subjects) using the Sequenom system.

Results

The genotype distributions and allele frequencies of each SNP in the control and patient groups were compared. rs201153092, rs13051496, rs199772854, rs76999397, and rs189013166 showed potential pathogenic loci for T-OPLL in the northern Chinese Han population, whereas rs151158105 did not. At the genotype level, the differences in the genotype frequencies of rs201153092, rs13051496, rs199772854, rs76999397, and rs189013166 between T-OPLL cases and controls reached statistical significance.

Conclusions

To the best of our knowledge, this is the first association study of susceptibility genes in Han Chinese patients with T-OPLL. The results revealed five SNPs in the IL17RC and COL6A1 genes that represented potentially pathogenic mutations in patients with T-OPLL.

The Pathogenesis of Ossification of the Posterior Longitudinal Ligament

Ossification of the posterior longitudinal ligament (OPLL) is a multi-factorial disease involving an ectopic bone formation of spinal ligaments. It affects 0.8-3.0% aging Asian and 0.1-1.7% aging European Caucasian. The ossified ligament compresses nerve roots in the spinal cord and causes serious neurological problems such as myelopathy and radiculopathy. Research in understanding pathogenesis of OPLL over the past several decades have revealed many genetic and non-genetic factors contributing to the development and progress of OPLL. The characterizations of aberrant signaling of bone morphogenetic protein (BMP) and mitogen-activated protein kinases (MAPK), and the pathological phenotypes of OPLL-derived mesenchymal stem cells (MSCs) have provided new insights on the molecular mechanisms underlying OPLL. This paper reviews the recent progress in understanding the pathophysiology of OPLL and proposes future research directions on OPLL.

Genetics of ossification of the posterior longitudinal ligament of the spine: a mini review

Ossification of the posterior longitudinal ligament of the spine (OPLL) is a common disease in aging populations and sometimes results in serious neurological problems due to compression of the spinal cord and nerve roots. OPLL is a multi-factorial (polygenic) disease controlled by genetic and environmental factors. Studies searching for the genetic component of OPLL, using linkage and association analyses, are in progress and several susceptibility genes have been reported. This paper reviews the recent progress in the genetic study of OPLL and comments on its future task.

Genetic diversity of Toll-like receptor 5 among pig populations

The Toll-like receptor 5 (TLR5) recognizes flagellin of Gram-positive and -negative bacteria and plays an important role in the host defense system. Here, we surveyed single nucleotide polymorphisms (SNPs) in the coding sequence of the porcine TLR5 gene in 83 individuals from five pig breeds, these including Chinese local populations and Western commercial pig breeds. A total of 19 medium polymorphic SNPs (0.25 < PIC < 0.5) were identified, three of which were missense mutations that clustered within the extracellular domain of TLR5. One of the non-synonymous SNPs fell within a 228-amino acid region which has been shown to be important for flagellin recognition. Four SNPs were only found with high frequencies in Oriental pig breeds. The 19 SNPs were found in 30 haplotypes, one of which segregated at high frequency in all samples. Compared with Western pig breeds, Chinese local populations had higher genetic diversity and more haplotypes. Tajima’s test showed no evidence for deviation from neutrality. The data provide useful information for future genetic marker characterization by means of disease association analysis and/or stimulating the mutation carrier with relevant ligands.

A genome-wide sib-pair linkage analysis of ossification of the posterior longitudinal ligament of the spine

Ossification of the posterior longitudinal ligament of the spine (OPLL) is a common musculoskeletal disease among people after middle age. The OPLL presents with serious neurological abnormalities due to compression of the spinal cord and nerve roots. The OPLL is caused by genetic and environment factors; however, its etiology and pathogenesis still remain to be elucidated. To determine the susceptibility loci for OPLL, we performed a genome-wide linkage study using 214 affected sib-pairs of Japanese. In stratification analyses for definite cervical OPLL, we found loci with suggestive linkage on 1p21, 2p22-2p24, 7q22, 16q24 and 20p12. Fine mapping using additional markers detected the highest non-parametric linkage score (3.43, P = 0.00027) at D20S894 on chromosome 20p12 in a subgroup that had no complication of diabetes mellitus. Our result would shed a new light on genetic aspects of OPLL.

Association of TLR5 sequence variants and mRNA level with cytokine transcription in pigs

The Toll-like receptor 5 (TLR5) plays a crucial role in host defense against flagellated bacteria by recognizing flagellin. Accumulating evidence suggests that single nucleotide polymorphisms (SNPs) in TLR5 have an effect on flagellin recognition and are associated with susceptibility/resistance to disease. In this study, we analyzed association of SNPs, including c.834T>G, c.1065T>C, c.1205C>T, c.1246A>T, c.1269G>A, and c.1398C>T, as well as mRNA level of TLR5 with the abundance of transcripts of cytokines in pigs. SNPs c.1246A>T and c.1269G>A were significantly associated with the transcript abundance of interleukin (IL)-2, and SNPs c.834T>G and c.1398C>T with IL-10 (P < 0.05); the haplotypes showed a tendency to affect the transcript abundance of IL-10 (P = 0.0660) and significantly associated with the transcription of TLR5 (P < 0.01); the abundance of transcripts of TLR5 and IL-10 were strongly correlated (P < 0.01). The results indicated that the SNPs, associated with the transcript abundance of cytokines, were related to immune responsiveness mediated by cytokine, which, in turn, would have a role in pig breeding for disease resistance. Furthermore, the positive correlation between the abundance of TLR5 and IL10 suggest a link between TLR5 activation and IL-10 expression in porcine.

Association study of fibroblast growth factor 2 and fibroblast growth factor receptors gene polymorphism in korean ossification of the posterior longitudinal ligament patients

OBJECTIVE

The aim of this study was to determine whether single nucleotide polymorphisms (SNPs) of fibroblast growth factor (FGF) 2 gene and fibroblast growth factor receptor (FGFR) genes are associated with ossification of the posterior longitudinal ligament (OPLL).

METHODS

A total of 157 patients with OPLL and 222 controls were recruited for a case control association study investigating the relationship between SNPs of FGF2, FGFR1, FGFR2 and OPLL. To identify the association among polymorphisms of FGF2 gene, FGFR1, FGFR2 genes and OPLL, the authors genotyped 9 SNPs of the genes (FGF2 : rs1476217, rs308395, rs308397, and rs3747676; FGFR1 : rs13317 and rs2467531; FGFR2 : rs755793, rs1047100, and rs3135831) using direct sequencing method. SNPs data were analyzed using the SNPStats, SNPAnalyzer, Haploview, and Helixtree programs.

RESULTS

Of the SNPs, a SNP (rs13317) in FGFR1 was significantly associated with the susceptibility of OPLL in the codominant (odds ratio=1.35, 95% confidence interval=1.01-1.81, p=0.048) and recessive model (odds ratio=2.00, 95% confidence interval=1.11-3.59, p=0.020). The analysis adjusted for associated condition showed that the SNP of rs1476217 (p=0.03), rs3747676 (p=0.01) polymorphisms in the FGF2 were associated with diffuse idiopathic skeletal hyperostosis (DISH) and rs1476217 (p=0.01) in the FGF2 was associated with ossification of the ligament flavum (OLF).

CONCLUSION

The results of the present study revealed that an FGFR1 SNP was significantly associated with OPLL and that a SNP in FGF2 was associated with conditions that were comorbid with OPLL (DISH and OLF).