The association between rs12901499 polymorphism in SMAD3 gene and risk of osteoarthritis: a meta-analysis

Inhibition of SMAD3 effectively reduces ADAMTS-5 expression in the early stages of osteoarthritis

OBJECTIVE

As one of the most important protein-degrading enzymes, ADAMTS-5 plays an important role in the regulation of cartilage homeostasis, while miRNA-140 is specifically expressed in cartilage, which can inhibit the expression of ADAMTS-5 and delay the progression of OA (osteoarthritis). SMAD3 is a key protein in the TGF-β signaling pathway, inhibiting the expression of miRNA-140 at the transcriptional and post-transcriptional levels, and studies have confirmed the high expression of SMAD3 in knee cartilage degeneration, but whether SMAD3 can mediate the expression of miRNA-140 to regulate ADAMTS-5 remains unknown.

METHODS

Sprague-Dawley (SD) rat chondrocytes were extracted in vitro and treated with a SMAD3 inhibitor (SIS3) and miRNA-140 mimics after IL-1 induction. The expression of ADAMTS-5 was detected at the protein and gene levels at 24 h, 48 h, and 72 h after treatment. The OA model of SD rats was created using the traditional Hulth method in vivo, with SIS3 and lentivirus packaged miRNA-140 mimics injected intra-articularly at 2 weeks, 6 weeks and 12 weeks after surgery. The expression of miRNA-140 and ADAMTS-5 in the knee cartilage tissue was observed at the protein and gene levels. Concurrently, knee joint specimens were fixed, decalcified, and embedded in paraffin prior to immunohistochemical, Safranin O/Fast Green staining, and HE staining analyses for ADAMTS-5 and SMAD3.

RESULTS

In vitro, the expression of ADAMTS-5 protein and mRNA in the SIS3 group decreased to different degrees at each time point. Meanwhile, the expression of miRNA-140 in the SIS3 group was significantly increased, and the expression of ADAMTS-5 in the miRNA-140 mimics group was also significantly downregulated (P < 0.05). In vivo, it was found that ADAMTS-5 protein and gene were downregulated to varying degrees in the SIS3 and miRNA-140 mimic groups at three time points, with the most significant decrease at the early stage (2 weeks) (P < 0.05), and the expression of miRNA-140 in the SIS3 group was significantly upregulated, similar to the changes detected in vitro. Immunohistochemical results showed that the expression of ADAMTS-5 protein in the SIS3 and miRNA-140 groups was significantly downregulated compared to that in the blank group. The results of hematoxylin and eosin staining showed that in the early stage, there was no obvious change in cartilage structure in the SIS3 and miRNA-140 mock groups. The same was observed in the results of Safranin O/Fast Green staining; the number of chondrocytes was not significantly reduced, and the tide line was complete.

CONCLUSION

The results of in vitro and in vivo experiments preliminarily showed that the inhibition of SMAD3 significantly reduced the expression of ADAMTS-5 in early OA cartilage, and this regulation might be accomplished indirectly through miRNA-140.

Differentiation of Induced Pluripotent Stem Cells Into Chondrocytes: Methods and Applications for Disease Modeling and Drug Discovery

Induced pluripotent stem cell (iPSC) technology allows pathomechanistic and therapeutic investigation of human heritable disorders affecting tissue types whose collection from patients is difficult or even impossible. Among them are cartilage diseases. Over the past decade, iPSC-chondrocyte disease models have been shown to exhibit several key aspects of known disease mechanisms. Concurrently, an increasing number of protocols to differentiate iPSCs into chondrocytes have been published, each with its respective (dis)advantages. In this review we provide a comprehensive overview of the different differentiation approaches, the hitherto described iPSC-chondrocyte disease models and mechanistic and/or therapeutic insights that have been derived from their investigation, and the current model limitations. Key lessons are that the most appropriate differentiation approach is dependent upon the cartilage disease under investigation and that further optimization is still required to recapitulate the in vivo cartilage. © 2022 American Society for Bone and Mineral Research (ASBMR).

The polymorphism of SMAD3 rs1065080 is associated with increased risk for knee osteoarthritis

The mechanism of knee osteoarthritis (OA) is still not clearly elucidated. SMAD3 gene polymorphisms are considered to play a vital role in OA pathogenesis. We thus investigated the relationship of SMAD3 rs1065080 gene polymorphism and susceptibility to knee osteoarthritis in a Chinese Han population. A total of 237 patients and 142 healthy control participants were enrolled in a case-control study. DNA was extracted from peripheral blood samples and genotyped by using the Mass-ARRAY method. Our results revealed that there was a significant difference between patients and healthy controls in the genotype of A and G (p = 0.019); those with a GG genotype had a significant increase in OA risk (OR 2.881, 95% CI 1.993-7.353, p = 0.025). In addition, logistic regression analysis showed that the recessive genetic model decreased OA morbidity (OR 0.648, 95% CI 0.416-0.911, p = 0.046). In conclusion, the GG genotype of rs1065080 was associated with a higher risk of OA and the recessive genetic model decreased the risk of OA.

Role of SREBP2 gene polymorphism on knee osteoarthritis in the South Indian Hyderabad Population: A hospital based study with G595C variant

Introduction

Osteoarthritis (OA) is a multifactorial disease with genetic factors playing a crucial role, and it has been associated with a family history of obesity. G595C polymorphism in the sterol regulatory element-binding protein 2 (SREBP2) gene has demonstrated an association with knee osteoarthritis (KOA) patients. However, this polymorphism has been never explored in an Indian population. Hence, the current study aimed to examine whether G595C (rs2228314) polymorphism in SREBP2 gene was associated with KOA susceptibility in the South Indian Hyderabad population.

Methods

G595C polymorphism was genotyped with 200 KOA cases and 200 healthy controls using polymerase chain reaction-restriction fragment length polymorphism analysis.

Results

A significant association was observed between age, body mass index (BMI), and family histories in KOA cases and controls (p < 0.05). The current allele (C vs G; OR-2.8 [95%CI = 2.1-3.7]; p < 0.0001) and genotype analysis confirms the significant association with (GC + CC vs GG; OR-3.5 [95%CI = 2.3-5.3]; p < 0.0001 & GC vs GG + CC; OR-1.7 [95%CI = 1.0-2.9]; p = 0.02) KOA vs. control subjects. On stratification analysis, genotype CC and C allele were associated with KOA. Gender association failed to demonstrate positive genotype frequencies (p > 0.05). Multifactor-dimensionality reduction (MDR) analysis showed a positive association with BMI and G595C genotypes (p < 0.05); 51% of the homozygous variant CC genotypes were present in obesity subjects.

Conclusion

In conclusion, our findings suggest that G595C polymorphism in SREBP2 gene is associated with KOA in the South Indian Hyderabad population and presents scope for further investigation of the gene's function in KOA.

Association between the polymorphisms of CALM1 gene and osteoarthritis risk: a meta-analysis based on observational studies

The existing studies on the association between polymorphisms of Calmodulin 1 (CALM1) gene and the risk of osteoarthritis (OA, a complex multifactorial disease and a major degenerative form of arthritis) in different populations have yielded conflicting findings. Therefore, we conducted a meta-analysis by systematically searching PubMed, Embase, Medline, Cochrane Library and Google Scholar, and assessing this association by calculating pooled odds ratios with 95% confidence intervals. Subgroup analyses stratified by ethnicity, OA type, and genotype were also conducted. Six studies (2752 cases and 3259 controls) involving six single nucleotide polymorphisms were included. Our data suggested that the T allele and genotype TT of the rs12885713 polymorphism, and the C allele of the rs2300496 polymorphism in the CALM1 gene all increased the risk of OA. The pooled results revealed no significant association between the CALM1 rs3213718 polymorphism and the risk of OA. Stratification analyses by ethnicity and OA type showed that the rs12885713 polymorphism increased the risk of OA among Asians and in knee OA, respectively. In conclusion, the rs12885713 and rs2300496 polymorphisms of the CALM1 gene may both increase the risk of OA. Owing to the limitations of the present study, this finding should be further confirmed in future well-designed studies.