Impact of the gene-gene interactions related to the HIF-1α signaling pathway with the knee osteoarthritis development

MiR203a-3p as a potential biomarker for synovial pathology associated with osteoarthritis: a pilot study

BACKGROUND

Osteoarthritis (OA) is a degenerative musculoskeletal disease that significantly impacts the quality of life. Currently, no validated biomarkers for early detection of OA are defined. The possibility of discovering OA biomarkers is the focus of this study.

METHODS

Human primary OA synovial cells (SVs), isolated from discarded joint tissue of patients with Kellgren & Lawrence score (KL) < 3, (mild/moderate) and KL ≥ 3 (severe), were characterized by FACS analysis. Through qRT-PCR and ELISA assays the inflammation, fibrosis status and the different miRNAs expression has been investigated. The role of miR-203a-3p and its precursors were evaluated through gain and loss of function study, IL-1β synoviocytes treatments and methylation analysis of miR203a promoter. The qRT-PCR analysis of miR203a-3p and pre-miR203a on plasma (isolated 24 h before surgery, 3 days and 1 month after surgery) and synovial fluid (recovered during the surgery) were done to support our in vitro data.

RESULTS

MiR203a-3p expression is inversely correlated with the aggressiveness of OA, modulating the expression of epithelial to mesenchymal transition (EMT) and pro-inflammatory factors, as well as regulating the expression of secreted protein acidic and rich in cysteine (SPARC) mRNA. Methylation analysis of the miR203a promoter and SVs IL-1β treatment's highlighted the impact of inflammation on miR203a-3p and pre-miR203a expression; as confirmed by both miRNAs detection in biological fluids derived from patients with severe OA.

CONCLUSION

Our preliminary results suggest that miR-203a-3p might be a potential candidate for staging OA progression and a new protective/predictive biomarker for synovial OA degeneration. Further studies are needed to validate its potential impact on OA.

Cartilage Targets of Knee Osteoarthritis Shared by Both Genders

As the leading cause of disability, osteoarthritis (OA) affects people of all ages, sexes, and races. With the increasing understanding of OA, the sex differences have attracted specific attention as the burden of OA is greater in women. There is no doubt that gender-specific OA management has great potential for precision treatment. On the other hand, from the marketing aspect, a medication targeting the OA-responsive biomarker(s) shared by both genders is more favorable for drug development. Thus, in the current study, a published transcriptome dataset of knee articular cartilage was used to compare OA and healthy samples for identifying the genes with the same significantly different expression trend in both males and females. With 128 genes upregulated and 143 genes downregulated in both OA males and females, 9 KEGG pathways have been enriched based on the current knowledge, including 'renal cell carcinoma,' 'ECM-receptor interaction,' 'HIF-1 signaling pathway,' 'MicroRNAs in cancer,' 'focal adhesion,' 'Relaxin signaling pathway,' 'breast cancer,' 'PI3K-Akt signaling pathway,' and 'human papillomavirus infection.' Here, we explore the potential impacts of these clusters in OA. We also analyze the identified 'cell plasma membrane related genes' in-depth to identify the potential chondrocyte cell surface target(s) of OA management.

Association study of the functional variants of the GLIS3 gene with risk of knee osteoarthritis

INTRODUCTION/OBJECTIVES

Osteoarthritis (OA) ranks the most common joint disorder and the leading cause of disability. Growing evidence has revealed that OA has a strong genetic background, except for aging and obesity. The aim of this study is to determine the associations between potential functional variants of the GLIS3 and GLIS3-AS1 gene and risk of knee OA among a Chinese population.

METHODS

In this case-control study with 810 knee OA cases and 900 healthy controls, seven selected functional SNPs of the GLIS3 and GLIS3-AS1 gene were evaluated.

RESULTS

We found minor alleles of rs10116772 (OR: 0.80, 95% CI: 0.69-0.92, P = 0.002), rs7045410 (OR: 0.74, 95% CI: 0.61-0.92, P = 0.005), and rs7032713 (OR: 0.76, 95% CI: 0.63-0.93, P = 0.006) were significantly associated with decreased risk of knee OA. Results of the dominant and recessive model, stratified analyses using Kellgren-Lawrence (KL) grading presented that the significant associations were not materially changed. Haplotype analysis indicated that haplotype CGT (OR: 0.66, 95% CI: 0.46-0.96, P = 0.031) and ATT (OR: 0.76, 95% CI: 0.6-0.95, P = 0.017) were significantly associated with decreased risk of knee OA. Further, they were also significantly associated with lower expression level of GLIS3, as well as higher expression level of GLIS3-AS1 in the articular cartilage specimens. Genotype-tissue expression (GTEX) data also validated that minor alleles of rs7045410 and rs7032713 were significantly associated with higher expression level of GLIS3-AS1 in thyroid and pituitary tissues (P < 0.001).

CONCLUSIONS

These findings revealed the essential role of genetic variants of the GLIS3 and GLIS3-AS1 gene in the occurrence of knee OA together. Key Point • Functional variants of the GLIS3 and GLIS3-AS1 gene were significantly associated with decreased risk of knee OA.

Hypoxia-inducible factor-1 alpha maintains mouse articular cartilage through suppression of NF-κB signaling

HIF-1α, an essential transcription factor under hypoxic condition, is indispensable for chondrocytes during skeletal development but its expression and roles in articular chondrocytes are yet to be revealed. We examined HIF-1α protein expression and the hypoxic condition during mouse osteoarthritis (OA) development using state of the art hypoxic probes and found that its expression decreased as OA progressed, coinciding with the change in hypoxic conditions in articular cartilage. Gain- and loss-of-function of HIF-1α in cell culture experiments showed that HIF-1α suppressed catabolic genes such as Mmp13 and Hif2a. We confirmed these anticatabolic effects by measuring glycosaminoglycan release from wild type and conditional knock-out mice femoral heads cultured ex vivo. We went on to surgically induce OA in mice with chondrocyte-specific deletion of Hif1a and found that the development of OA was exacerbated. Increased expression of catabolic factors and activation of NF-κB signalling was clearly evident in the knock-out mice. By microarray analysis, C1qtnf3 was identified as a downstream molecule of HIF-1α, and experiments showed it exerted anti-catabolic effects through suppression of NF-κB. We conclude that HIF-1α has an anti-catabolic function in the maintenance of articular cartilage through suppression of NF-κB signalling.

Multifactor dimensionality reduction reveals a strong gene-gene interaction between STC1 and COL11A1 genes as a possible risk factor of knee osteoarthritis

Articular cartilage is an avascular tissue with a structure that allows it to support and cushion the overload of the surfaces in contact. It maintains its metabolic functions due to the contribution of different signaling pathways. However, several factors play a role in its deterioration, allowing to the development of osteoarthritis (OA), and one of the major factors is genetic. Our goal was to identify gene-gene interactions (epistasis) between five signaling pathways involved in the articular cartilage metabolism as possible indicators of OA risk. We applied the Multifactor-Dimensionality Reduction (MDR) method to identify and characterize the epistasis between 115 SNPs located in 73 genes related to HIF-1α, Wnt/β-catenin, cartilage extracellular matrix metabolism, oxidative stress, and uric acid transporters. Ninety three patients diagnosed with primary knee OA and 150 healthy controls were included in the study. Genotyping was performed with the OpenArray system, the statistical analysis was carried out with the STATA software v14, and epistasis was analyzed with the MDR software v3.0.2. The MDR analysis revealed that the best interaction model was between polymorphisms rs17786744 of the STC1 gene and rs2615977 of the COL11A1 gene, with an entropy value of 4.44%, CVC 8/10, OR 5.60, 95% CI 3.27-9.59, p < 0.0001. Under this interaction model, we identified high and low risk genotypes involved in OA development. Our results suggest complex interactions between STC1 and COL11A1 genes that might have an impact on genetic susceptibility to develop OA. Further studies are required to confirm it.