Zinc finger protein 521 attenuates osteoarthritis via the histone deacetylases 4 in the nucleus

Intraarticular gold for knee osteoarthritis: An ancillary analysis of biomarkers and outcome of a pilot study

Objective

In a previous pilot study, we have shown that intraarticular gold micro-particles can reduce knee osteoarthritis (KOA) pain at two years follow-up. Proteomic changes in serum and synovial fluid within eight weeks were associated with multiple inflammatory and immunological processes. The relation between the different biomarkers and the outcome measures is not known. We hypothesized that improvement in pain and function were associated with specific groups of biomarkers. We present the integrative analyses between proteomic biomarkers and outcomes.

Design

A cohort of 30 patients, with moderate KOA, were included. Using the patients' synovial fluid as the carrier, 20 ​mg gold microparticles were injected intraarticularly. Clinical outcome measures at inclusion, 8 weeks, and 2 years, were the PainDetect questionnaire, WOMAC pain, stiffness, and function. In addition, Quantitative Sensory Testing, Pain Pressure Threshold, Temporal Summation, Conditioned Pain Modulation, and pain diary were assessed at inclusion and after 8 weeks. Proteomic analysis was performed on SF and blood samples before and after 8 weeks of treatment.

Results

Linear combinations of serum or synovial biomarkers changed significantly alongside the effect measures and PainDetect scores following gold micro-particle treatment. Of particular interest was identifying multiple members of a molecular complex that is suggestive of neural tissue regeneration and modulation following gold micro-particle treatment.

Conclusions

Gold microparticles are a possible future option for the treatment of knee osteoarthritis. The treatment triggers putative regenerative and inflammation-modulating molecular mechanisms.

The Impact of Selenium Deficiency and T-2 Toxin on Zip6 Expression in Kashin-Beck Disease

This study investigated the expression of Zip6, a gene predominantly located in the placenta, breast, and prostate tissues, in patients with Kashin-Beck disease (KBD). Environmental risk factor models for KBD were developed using low selenium (Se) feeding (with a Se content of 0.02 mg Se/kg in the feed) and exposure to T-2 toxin (200 ng/g*BW/D). Additionally, the study examined the alterations in Se and Zn2+ levels, along with the mRNA and protein expression levels of Zip6 and KBD related genes, including Mtf1, Mmp3, Mmp13, Adamts5, and Col2a1. Differentially expressed genes (DEGs) were examined by transcriptome sequencing to elucidate the mechanism by which Zip6 induces metabolic disorder of the extracellular matrix (ECM), subsequently leading to cartilage injury under the influence of Se deficiency and T-2 toxin. The findings indicated that the expression levels of Zip6 in adult and pediatric KBD chondrocytes were not synchronized. In the animal study, there was a notable increase in the Zn2+ level in the comprehensive exposure (CE) group. Moreover, in both the T-2 exposure (T-2) and CE groups, there was a significant decrease in the expression of Zip6 in each zone, and the expression of Adamts5 in the middle zone exhibited a significant increase (P < 0.05) correlating with varying degrees of cartilage tissue damage in each group. Sequencing results revealed that the significantly up-regulated DEGs in the CE group included Zimz2. This study suggested that Se and T-2 toxin may influence the expression of Zip6, and it investigated the role of Zn2+ in the pathogenesis of KBD, thereby providing a novel scientific foundation for understanding the pathogenesis of KBD.

The N-terminal fragment of histone deacetylase 4 (1-669aa) promotes chondrocyte apoptosis via the p53-dependent endoplasmic reticulum stress pathway

Exogenous administration of the histone deacetylation 4 (HDAC4) protein can effectively delay osteoarthritis (OA) progression. However, HDAC4 is unstable and easily degrades into N-terminal (HDAC4-NT) and C-terminal fragments, and the HDAC4-NT can exert biological effects, but little is known about its role in chondrocytes and cartilage. Thus, the roles of HDAC4-NT fragments (1-289aa, 1-326aa and 1-669aa) in chondrocytes and cartilage were evaluated via real-time cell analysis (RTCA), safranin O staining, Sirius Red staining and nanoindentation. Molecular mechanisms were profiled via whole-transcriptome sequencing (RNA-seq) and verified in vitro and in vivo by a live cell real-time monitoring system, flow cytometry, western blotting and immunohistochemistry. The results showed that 1-669aa induced chondrocyte death and cartilage injury significantly, and the differentially expressed genes (DEGs) were enriched mainly in the apoptotic term and p53 signalling pathway. The validation experiments showed that 1-669aa induced chondrocyte apoptosis via the endoplasmic reticulum stress (ERS) pathway, and up-regulated p53 expression was essential for this process. Thus, we concluded that the HDAC4-NT fragment 1-669aa induces chondrocyte apoptosis via the p53-dependent ERS pathway, suggesting that in addition to overexpressing HDAC4, preventing it from degradation may be a new strategy for the treatment of OA.

Metalloproteins as risk factors for osteoarthritis: improving and understanding causal estimates using Mendelian randomization

Osteoarthritis (OA) is one of the most prevalent musculoskeletal disorders and a primary cause of pain and disability among the elderly population. Research on the relationship between metalloproteins (MPs) and OA is limited, and causality remains unclear. Our objective is to utilize Mendelian randomization (MR) to explore the possible causal relationship between MPs and OA. The data on MPs were derived from a Genome-Wide Association Study (GWAS) analysis involving 3301 samples. The GWAS data for OA were obtained from an analysis involving 462,933 European individuals. In this study, a variety of two-sample Mendelian randomization methods (two-sample MR) to evaluate the causal effect of MPs on OA, including inverse variance weighted method (IVW), MR-Egger method, weighted median method (WM), simple mode, weight mode, and Wald ratio. The primary MR analysis using the IVW method reveals a significant negative correlation between Metallothionein-1F (MT-1F), zinc finger protein 134 (ZNF134), calcium/calmodulin-dependent protein kinase type 1D (CAMK1D), and EF-hand calcium-binding domain-containing protein 14 (EFCAB14) with the occurrence of osteoarthritis (OA) (p value < 0.05). However, no causal relationship was observed in the opposite direction between these MPs and OA. Notably, even in combined models accounting for confounding factors, the negative association between these four MPs and OA remained significant. Sensitivity analysis demonstrated no evidence of horizontal pleiotropy or heterogeneity, and leave-one-out analysis confirmed the robustness of the results. In this study, we have established a conspicuous association between four distinct MPs and OA. This discovery augments our understanding of potential avenues for the diagnosis and treatment of this condition. Key Points • The MR method was employed to assess the relationship between MPs and OA. • A total of four types of MPs have demonstrated inhibitory effects on the occurrence of OA.

TSP-1 increases autophagy level in cartilage by upregulating HSP27 which delays progression of osteoarthritis

This study aimed to determine whether Thrombospondin-1 (TSP-1) can be used as a biomarker to diagnose early osteoarthritis (OA) and whether it has a chondroprotective effect against OA. We examined TSP-1 expression in cartilage, synovial fluid, and serum at different time points after anterior cruciate ligament transection (ACLT) surgery in rats. Subsequently, TSP-1 was overexpressed or silenced to detect its effects on extracellular matrix (ECM) homeostasis, autophagy level, proliferation and apoptosis in chondrocytes. Adenovirus encoding TSP-1 was injected into the knee joints of ACLT rats to test its effect against OA. Combined with proteomic analysis, the molecular mechanism of TSP-1 in cartilage degeneration was explored. Intra-articular injection of an adenovirus carrying the TSP-1 sequence showed chondroprotective effects against OA. Moreover, TSP-1 expression decreases with OA progression and can effectively promote cartilage proliferation, inhibit apoptosis, and helps to sustain the balance between ECM anabolism and catabolism. Overexpression of TSP-1 also can increase autophagy by upregulating Heat Shock Protein 27 (HSP27, hspb1), thereby enhancing its effect as a stimulator of autophagy. TSP-1 is a hopeful strategy for OA treatment.