Association between RANK, RANKL and OPG polymorphisms with ACPA and erosions in rheumatoid arthritis: results from a meta-analysis involving three French cohorts

Multiple Factors Involved in Bone Damage Caused by Chikungunya Virus Infection

Chronic cases of chikungunya fever represent a public health problem in countries where the virus circulates. The disease is prolonged, in some cases, for years, resulting in disabling pain and bone erosion among other bone and joint problems. As time progresses, tissue damage is persistent, although the virus has not been found in blood or joints. The pathogenesis of these conditions has not been fully explained. Additionally, it has been considered that there are multiple factors that might intervene in the viral pathogenesis of the different conditions that develop. Other mechanisms involved in osteoarthritic diseases of non-viral origin could help explain how damage is produced in chronic conditions. The aim of this review is to analyze the molecular and cellular factors that could be involved in the tissue damage generated by different infectious conditions of the chikungunya virus.

Pathomechanisms of bone loss in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease, in which the inflammatory processes involve the skeletal system and there is marked destruction of the bones and the surrounding structures. In this review, we discuss the current concepts of osteoimmunology in RA, which represent the molecular crosstalk between the immune and skeletal systems, resulting in the disruption of bone remodeling. Bone loss in RA can be focal or generalized, leading to secondary osteoporosis. We have summarized the recent studies of bone loss in RA, which focused on the molecular aspects, such as cytokines, autoantibodies, receptor activator of nuclear kappa-β ligand (RANKL) and osteoprotegerin (OPG). Apart from the above molecules, the role of aryl hydrocarbon receptor (Ahr), which is a potential key mediator in this process through the generation of the Th17 cells, is discussed. Hence, this review highlights the key insights into molecular mechanisms of bone loss in RA.

Osteoprotegerin and MTHFR gene variations in rheumatoid arthritis: association with disease susceptibility and markers of subclinical atherosclerosis

We aimed to explore whether the rs2073618 variant (G1181C) of the osteoprotegerin (OPG) gene and the methylenetetrahydrofolate reductase (MTHFR) rs1801131 (A1298AC) and rs1801133 (C677T) gene polymorphisms contribute to rheumatoid arthritis (RA) susceptibility and RA related subclinical atherosclerosis. Overall 283 RA patients and 595 healthy controls (HC) were genotyped for common variants of the OPG and MTHFR genes using PCR based assays. Clinical and laboratory parameters were recorded following thorough chart review. Surrogate markers of subclinical atherosclerosis (Carotid/Femoral intima media thickness/plaque formation) along with traditional risk factors for atherosclerosis were assessed in all RA patients and 280HC. Increased prevalence of the CC genotype of the rs2073618 variant was detected in RA patients vs HC (42.4% vs. 33%, p-value: 0.04). RA patients with high serum titers of rheumatoid factor (RF) or anti-cyclic citrullinated peptide (CCP) antibodies displayed increased prevalence of the CC genotype of the rs2073618 variant of the OPG gene compared to HC (48.6% and 47.5 vs 33.3%, p-values: 0.0029and 0.0077 respectively). Of interest, this genotype turned to be associated with higher carotid IMT scores (0.872 ± 0.264 vs 0.816 ± 0.284, p-value: 0.01) and marginally with higher rates of carotid plaque formation (66% vs 54.1%, p = 0.06). The MTHFR 1298CC genotype was more prevalent only in the anti-CCP positive group compared to HC, with no associations detected with markers of subclinical atherosclerosis, following adjustment for traditional cardiovascular (CVD) risk factors. Reduced rates of carotid/femoral plaque formation were detected among RA patients harboring the MTHFR TT genotype (52.4 vs 72.7, p-value: 0.009, respectively). This association remained significant following adjustment for classical CVD risk factors (OR [95% CI 0.364 [0.173–0.765], p-value: 0.008). Genetic variations of the osteoprotegerin and MTHFR genes seem to increase susceptibility for seropositive RA and potentially contribute to subclinical atherosclerosis linked to RA. Larger studies are needed to confirm these findings.

Association of RANK and RANKL gene polymorphism with survival and calcium levels in multiple myeloma

Multiple myeloma (MM) is a heterogeneous bone marrow cancer characterized by proliferation of malignant plasma cells in the bone marrow. One of its major symptoms are hypercalcaemia and bone lesions, which may result in pathologic bone fractures. Receptor activator for nuclear factor κB (RANK) and its ligand, RANKL, are part of an activation pathway for osteoclasts and are thus responsible for bone resorption. Furthermore, RANKL expression is increased in multiple myeloma. In the present study, we investigated the role of single nucleotide polymorphisms (SNPs) in the genes coding for RANK (rs1805034, rs8086340), RANKL (rs7325635, rs7988338), and TACI (rs34562254), a receptor for osteoclast-derived pro-survival factors. The study involved 222 patients and 222 healthy individuals, and the analysis included disease susceptibility, survival, bone lesions, calcium levels, and vascular endothelial growth factor levels. Patients with allele RANK rs1805034 C had higher survival (p = .003). This relationship was especially evident in women (p = .006). Furthermore, allele rs1805034 C was associated with slightly lower median age at diagnosis (64.0 vs. 65.5, p = .008). Allele RANKL rs7325635 A correlated with lower progression-free survival (p = .027), and with lack of early progression (p = .023). Additionally, women with allele rs7325635 G were found to have higher calcium blood concentration (p = .040). Allele TACI rs34562254 A was more common in MM patients in more advanced stages (II and III stage International Staging System) at diagnosis (p = .017), and the SNP showed a slight trend towards association in a multivariate analysis (p = .084). Taken together, our results suggest that RANK rs1805034 and RANKL rs7325635 may have a role in MM development and progression.

Polymorphisms within the RANK and RANKL Encoding Genes in Patients with Rheumatoid Arthritis: Association with Disease Progression and Effectiveness of the Biological Treatment

Inconsistency of the results regarding the genetic variability within genes coding for receptor activator of nuclear factor κB (RANK) and its ligand (RANKL) in rheumatoid arthritis (RA) prompted us to study the RANK and RANKL polymorphisms as potential biomarkers associated with disease predisposition and response to anti-TNF treatment in a group of Polish patients with RA. This study enrolled 318 RA patients and 163 controls. RANK (rs8086340, C > G; rs1805034, C > T) and RANKL (rs7325635, G > A; rs7988338 G > A) alleles were determined by real-time PCR with melting curve analysis and related with clinical parameters. In addition, RANKL serum levels were measured by ELISA. The RANK rs8086340-G allele was overrepresented among patients as compared to controls (OD = 1.777, p = 0.038). C-reactive protein (CRP) levels were significantly (p < 0.05) associated with RANK rs8086340 polymorphism and were higher in the CC-homozygotes at the baseline while lower in the GG-carriers at the 12th week of the treatment. At the latter time point RANKL rs7325635-GG-positive patients also showed significantly lower CRP concentrations. Higher alkaline phosphatase levels before induction of anti-TNF therapy were observed in RANK rs8086340 and RANK rs1805034 CC homozygotes (p = 0.057 and p = 0.035, respectively). The GG homozygosity of both RANKL single nucleotide polymorphisms was significantly associated with the number of swollen joints (rs7988338 and rs7325635, before and at the 12th week of therapy, respectively, p < 0.05 in both cases). These results imply that polymorphisms within the RANK and RANKL genes affect RA susceptibility and anti-TNF treatment outcome.

The association between RANK, RANKL and OPG gene polymorphisms and the risk of rheumatoid arthritis: a case-controlled study and meta-analysis

The receptor activator of nuclear factor-κB (RANK) and the osteoprotegerin (OPG) cascade system have been reported to be essential in osteoclastogenesis. In recent years, several studies have investigated the association between polymorphisms of RANK, its ligand RANKL and OPG genes and the risk of rheumatoid arthritis (RA) in different populations. However, the results arising from these studies were conflicting. To determine the association between RANK, RANKL and OPG gene polymorphisms and the risk of RA. We conducted a hospital-based case-controlled study in Changzhou with 574 RA cases and 804 controls. The genotyping of RANK gene rs1805034 polymorphism was conducted by single base extension combined with matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). We also undertook a meta-analysis of the literature referring to polymorphisms of RANK, RANKL and OPG genes and RA risk. This case-controlled study found that the polymorphism in the RANK gene rs1805034 was not related to RA risk. Stratification analyses by sex and age suggested that RANK gene rs1805034 polymorphism was not associated with the risk of RA among groups of male, female, age ≤ 55 and age > 55. Our meta-analysis found that the rs2277438 polymorphism in RANKL gene increased the risk of RA, whereas RANK gene rs1805034, OPG gene rs3102735, OPG gene rs2073618, OPG gene rs3134069 polymorphisms were not related to RA susceptibility. In conclusion, this case-controlled study and meta-analysis indicated that the RANKL gene rs2277438 polymorphism increased the RA risk, and that RANK gene rs1805034, OPG gene rs3102735, OPG gene rs2073618, OPG gene rs3134069 polymorphisms were not related to RA risk.

Association of Variant Interactions in RANK, RANKL, OPG, TRAF6, and NFATC1 Genes with the Development of Osteonecrosis of the Femoral Head

Multiple gene polymorphisms have been demonstrated to correlate with the susceptibility to osteonecrosis of the femoral head (ONFH). However, as a complex disease induced by multiple genes, the development of ONFH has rarely been reported to involve in gene interaction. In this study, we first explored the association of 10 variants interactions in receptor activator of nuclear factor-kappa B (RANK), RANK ligand (RANKL), osteoprotegerin (OPG), tumor necrosis factor receptor-associated factor 6 (TRAF6), and nuclear factor of activated T cells cytoplasmic 1 (NFATC1) genes with the development and clinical phenotypes of ONFH in a 377 ONFH case-control study with using Mass ARRAY^® platform. Our results showed that not only a total of 6 interactional variants in the paired 10 variants interactions were significantly associated with the development of ONFH (OPG rs2073617 and NFATC1 rs754093, p < 0.019; OPG rs2073618 and NFATC1 rs754093, p < 0.008; OPG rs2073617 and RANKL rs1054016, p < 0.039, respectively) but also a total of 4 paired interactional variants were found to involve significantly in the increased risk of bilateral hip lesions in ONFH (OPG rs2073617 and TRAF6 rs5030411, p = 0.044; RANK rs884205 and TRAF6 rs5030411, p = 0.045, respectively). Moreover, the results from generalized multifactor dimensionality reduction also showed that the five best models were identified and associated significantly with ONFH risk, p = 0.001, 0.01, 0.01, 0.01, and 0.01, respectively. Our results first suggest that the variants in RANK/RANKL/OPG pathway genes affected the development of ONFH in gene interaction manner through the interaction of the paired variants and multiple variants.

Effects of receptor activator nuclear factor κB gene polymorphisms on the susceptibility to knee osteoarthritis: A case-control study

The present study aimed to explore genetic association of receptor activator nuclear factor κB (RANK) polymorphisms with individual susceptibility to knee osteoarthritis (OA) in different Kellgren-Lawrence (KL) grades.This case-control study included 138 knee OA patients and 145 healthy individuals. RANK rs1805034 and rs8086340 polymorphisms were genotyped through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The effects of RANK polymorphisms on knee OA risk were analyzed via χ test or Fisher exact test, and the results were expressed using odds ratios (ORs) with corresponding 95% confidence intervals (CIs).The C allele of rs1805034 polymorphism had significantly higher frequency in knee OA patients than in controls (P = .044), indicating that this allele could increase the risk of knee OA (OR = 1.424, 95% CI = 1.010-2.008). Besides, the CC genotype and C allele of the rs1805034 polymorphism were significantly associated with elevated risk of knee OA in moderate grade (CC vs TT: P = .018, OR = 3.071, 95% CI = 1.187-7.941; C vs T: P = .012, OR = 1.787, 95% CI = 1.131-2.823). However, rs8086340 polymorphism had no significant association with knee OA riskThe C allele of RANK rs1805034 polymorphism is closely correlated with increased risk of knee OA, especially for moderate grade.

Chikungunya Virus-Induced Arthritis: Role of Host and Viral Factors in the Pathogenesis

Chikungunya virus (CHIKV), a member of Alphavirus genus, is responsible for chikungunya fever (CHIKF), which is characterized by the presence of fever, rash, myalgia, and arthralgia. Reemergence of CHIKV has become a significant public health concern in Asian and African countries and is newly emerging in the Middle East, Pacific, American, and European countries. Cytokines, innate (monocytes, natural killer cells) and adaptive immune response (role of B cells and T cells i.e. CD4⁺ and CD8⁺), and/or viral factors contribute to CHIKV-induced arthritis. Vector factors such as vector competence (that includes extrinsic and intrinsic factors) and effect of genome mutations on viral replication and fitness in mosquitoes are responsible for the spread of virus, although they are not directly responsible for CHIKV-induced arthritis. CHIKV-induced arthritis mimics arthritis by involving joints and a common pattern of leukocyte infiltrate, cytokine production, and complement activation. Successful establishment of CHIKV infection and induction of arthritis depends on its ability to manipulate host cellular processes or host factors. CHIKV-induced joint damage is due to host inflammatory response mediated by macrophages, T cells, and antibodies, as well as the possible persistence of the virus in hidden sites. This review provides insight into mechanisms of CHIKV-induced arthritis. Understanding the pathogenesis of CHIKV-induced arthritis will help in developing novel strategies to predict and prevent the disease in virus-infected subjects and combat the disease, thereby decreasing the worldwide burden of the disease.