Circ_0114876 promoted IL-1β-induced chondrocyte injury by targeting miR-671/TRAF2 axis

CircTBX5 knockdown modulates the miR-558/MyD88 axis to alleviate IL-1β-induced inflammation, apoptosis and extracellular matrix degradation in chondrocytes via inactivating the NF-κB signaling

BACKGROUND

It has been widely shared that the dysregulation of circular RNA (circRNA) may contribute to the progression of osteoarthritis (OA). OA is characterized by persistent chondrocyte injury. We aimed to clarify the role of circTBX5 in IL-1β-induced chondrocyte injury.

METHODS

The expression of circTBX5, miR-558 and MyD88 mRNA was measured using quantitative real-time PCR (qPCR). Cell viability, proliferation and apoptosis were assessed by CCK-8, EdU or flow cytometry assay. The protein levels of extracellular matrix (ECM)-associated markers, MyD88, IkBα, p65 and phosphorylated IkBα were measured by western blot. The release of inflammatory factors was assessed by ELISA. The targets of circTBX5 were screened by RIP and pull-down assay. The putative binding between miR-558 and circTBX5 or MyD88 was validated by dual-luciferase reporter assay.

RESULTS

CircTBX5 and MyD88 were enhanced, while miR-558 was downregulated in OA cartilage tissues and IL-1β-treated C28/I2 cells. IL-1β induced C28/I2 cell injury by impairing cell viability and proliferation and promoting cell apoptosis, ECM degradation and inflammatory response, while circTBX5 knockdown alleviated IL-1β induced injury. CircTBX5 bound to miR-558 to regulate IL-1β induced cell injury. In addition, MyD88 was a target of miR-558, and circTBX5 targeted miR-558 to positively regulate MyD88 expression. MiR-558 enrichment attenuated IL-1β induced injury by sequestering MyD88 expression. Moreover, circTBX5 knockdown weakened the activity of NF-κB signaling, while miR-558 inhibition or MyD88 overexpression recovered the activity of NF-κB signaling.

CONCLUSION

CircTBX5 knockdown modulated the miR-558/MyD88 axis to alleviate IL-1β induced chondrocyte apoptosis, ECM degradation and inflammation via inactivating the NF-кB signaling pathway.

CircRNAs in osteoarthritis: research status and prospect

Osteoarthritis (OA) is the most common joint disease globally, and its progression is irreversible. The mechanism of osteoarthritis is not fully understood. Research on the molecular biological mechanism of OA is deepening, among which epigenetics, especially noncoding RNA, is an emerging hotspot. CircRNA is a unique circular noncoding RNA not degraded by RNase R, so it is a possible clinical target and biomarker. Many studies have found that circRNAs play an essential role in the progression of OA, including extracellular matrix metabolism, autophagy, apoptosis, the proliferation of chondrocytes, inflammation, oxidative stress, cartilage development, and chondrogenic differentiation. Differential expression of circRNAs was also observed in the synovium and subchondral bone in the OA joint. In terms of mechanism, existing studies have mainly found that circRNA adsorbs miRNA through the ceRNA mechanism, and a few studies have found that circRNA can serve as a scaffold for protein reactions. In terms of clinical transformation, circRNAs are considered promising biomarkers, but no large cohort has tested their diagnostic value. Meanwhile, some studies have used circRNAs loaded in extracellular vesicles for OA precision medicine. However, there are still many problems to be solved in the research, such as the role of circRNA in different OA stages or OA subtypes, the construction of animal models of circRNA knockout, and more research on the mechanism of circRNA. In general, circRNAs have a regulatory role in OA and have particular clinical potential, but further studies are needed in the future.

CircRNA-mediated ceRNA mechanism in Osteoarthritis: special emphasis on circRNAs in exosomes and the crosstalk of circRNAs and RNA methylation

Osteoarthritis (OA) is an age-related joint disease with chronic inflammation, progressive articular cartilage destruction and subchondral bone sclerosis. CircRNAs (circRNAs) are a class of non-coding RNA with a circular structure that participate in a series of important pathophysiological processes of OA, especially its ceRNA mechanisms, and play an important role in OA. CircRNAs may be potential biomarkers for the diagnosis and prognosis of OA. Additionally, differentially expressed circRNAs were found in patients with OA, indicating that circRNAs are involved in the pathogenesis of OA. Experiments have shown that the intra-articular injection of modified circRNAs can effectively relieve OA. Exosomal circRNAs and methylated circRNAs also provide new ideas for the treatment of OA. Clarifying the important roles of circRNAs in OA will deepen people's understanding of the pathogenesis of OA. CircRNAs may be developed as new biomarkers or drug targets for the diagnosis of OA and provide new methods for the treatment of OA.

Circular RNA circ_0114876 regulates osteoarthritis through upregulating ADAM10 via targeting miR-1227-3p

BACKGROUND

Osteoarthritis (OA) was a chronic degenerative joint disease. The dysregulation of circular RNAs (circRNAs) has been identified in OA progression. However, the function and regulation mechanism of circ_0114876 in OA remains largely unknown.

METHOD

Firstly, we used LPS-treated C28/I2 cells as a cellular model of OA. Quantificational real-time polymerase chain reaction (qRT-PCR) was used to determine the expression levels of circ_0114876, miRNA-1227-3p, and ADAM10 in OA chondrocytes. Cell Counting Kit-8 (CCK8), 5-ethynyl-20-deoxyuridine (EdU) incorporation assays, flow cytometry, Enzyme-linked immunosorbent assay (ELISA) kit, and western blot were applied to confirm cell proliferation, apoptosis, inflammation, and extracellular matrix. of circ_0114876 in vitro. The interaction between circ_0114876 and its downstream target (miR-1227-3p) and mRNA target ADAM metallopeptidase domain 10 (ADAM10), was evaluated by luciferase assay and RNA immunoprecipitation (RIP) assay.

RESULT

Circ_0114876 and ADAM10 were upregulated and miR-1227-3p was decreased in OA tissues and LPS-treated chondrocytes. Low expression of circ_0114876 promoted proliferation and inhibited apoptosis, inflammation, and extracellular matrix of the LPS-treated chondrocytes. Mechanistically, circ_0114876 functioned in human chondrocytes through targeting miR-1227-3p and ADAM10. Furthermore, miRNA-1227-3p inhibitor reversed the effect of circ_0114876 knockdown on the OA chondrocytes, and ADAM10 overexpression reversed the effect of miR-1227-3p mimic on the OA chondrocytes.

CONCLUSION

Circ_0114876 was increased in OA tissues and cells. Circ_0114876 facilitated the progression in the LPS-induced OA cell model via regulating the miR-1227-3p/ADAM10 axis. This study would provide a potentially effective therapeutic strategy for OA progression.

The Role of Regulated Programmed Cell Death in Osteoarthritis: From Pathogenesis to Therapy

Osteoarthritis (OA) is a worldwide chronic disease that can cause severe inflammation to damage the surrounding tissue and cartilage. There are many different factors that can lead to osteoarthritis, but abnormally progressed programmed cell death is one of the most important risk factors that can induce osteoarthritis. Prior studies have demonstrated that programmed cell death, including apoptosis, pyroptosis, necroptosis, ferroptosis, autophagy, and cuproptosis, has a great connection with osteoarthritis. In this paper, we review the role of different types of programmed cell death in the generation and development of OA and how the different signal pathways modulate the different cell death to regulate the development of OA. Additionally, this review provides new insights into the radical treatment of osteoarthritis rather than conservative treatment, such as anti-inflammation drugs or surgical operation.

Implications and theragnostic potentials of circular RNAs in rheumatic diseases

Circular RNAs (circRNAs), a class of non-coding RNAs (ncRNAs), are highly stable and ubiquitous molecules that exhibit tissue-specific expression. Accumulating evidence has shown that aberrant expression of circRNAs can play a role in the pathogenesis of several diseases. Rheumatic diseases are a varied group of autoimmune and inflammatory disorders affecting mainly the musculoskeletal system. Notably, circRNAs, which are essential immune system gene modulators, are strongly linked to the occurrence and progression of autoimmune disorders. Here, we present and discuss the current findings concerning the roles, implications and theragnostic potentials of circRNAs in common rheumatic diseases, including ankylosing spondylitis (AS), osteoarthritis (OA), osteoporosis (OP), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Crohn's disease (CD), and gout. This review aims to provide new insights to support the development of novel diagnostic and therapeutic strategies for these disabling diseases.

Circular RNAs: typical biomarkers for bone-related diseases

Bone is a connective tissue that has important functions in the human body. Cells and the extracellular matrix (ECM) are key components of bone and are closely related to bone-related diseases. However, the outcomes of conventional treatments for bone-related diseases are not promising, and hence it is necessary to elucidate the exact regulatory mechanisms of bone-related diseases and identify novel biomarkers for diagnosis and therapy. Circular RNAs (circRNAs) are single-stranded RNAs that form closed circular structures without a 5' cap or 3' tail and polycyclic adenylate tails. Due to their high stability, circRNAs have the potential to be typical biomarkers. Accumulating evidence suggests that circRNAs are involved in bone-related diseases, including osteoarthritis, osteoporosis, osteosarcoma, multiple myeloma, intervertebral disc degeneration, and rheumatoid arthritis. Herein, we summarize the recent research progress on the characteristics and functions of circRNAs, and highlight the regulatory mechanism of circRNAs in bone-related diseases.

A review on the role of miR-671 in human disorders

miR-671 is encoded by a gene on 7q36.1 and contributes to the pathogenesis of a variety of disorders, including diverse types of cancers, atherosclerosis, ischemic stroke, liver fibrosis, osteoarthritis, Parkinson's disease, rheumatoid arthritis, acute myocardial infarction and Crohn's disease. In the context of cancer, different studies have revealed opposite roles for this miRNA. In brief, it has been shown to be down-regulated in pancreatic ductal carcinoma, ovarian cancer, gastric cancer, osteosarcoma, esophageal squamous cell carcinoma and myelodysplastic syndromes. Yet, miR-671 has been up-regulated in glioma, colorectal cancer, prostate cancer and hepatocellular carcinoma. Studies in breast, lung and renal cell carcinoma have reported inconsistent results. The current review aims at summarization of the role of miR-671 in these disorders focusing on its target mRNA in each context and dysregulated signaling pathways. We also provide a summary of the role of this miRNA as a prognostic factor in malignancies.

Celastrol ameliorates osteoarthritis via regulating TLR2/NF-κB signaling pathway

Objectives: Osteoarthritis (OA) is a joint disease characterized by degeneration of joint cartilage and is a significant cause of severe joint pain, physical disability, and impaired quality of life in the aging population. Celastrol, a Chinese herbal medicine, has attracted wide interests because of its anti-inflammatory effects on a variety of diseases. This study aimed to investigate the effect of celastrol on OA as well as the mechanisms in vivo and in vitro.

Methods: A rat knee OA model was established using “medial collateral ligament transection (MCLT) + partial meniscectomy (pMMT)”. Eight weeks after surgery, the OA rats started to receive intra-articular injection of celastrol (1 mg/kg) once a week. Safranin O-fast green (S&F) and hematoxylin and eosin (H&E) staining were used to estimate histopathological changes. Micro-CT was used to evaluate bone volume of the subchondral bone of the knee joint. Chondrocytes were isolated from the knee cartilage of rats and OA patients. Enzyme linked immunosorbent assay (ELISA), Western Blot (WB), Polymerase Chain Reaction (PCR), and Immunohistochemistry (IHC) were used to detect the expression of inflammatory factors and stromal proteins, respectively.

Results: We found that celastrol treatment significantly delayed the progression of cartilage damage with a significant reduction in osteophyte formation and bone resorption in OA rat model. In IL-1β-stimulated rat chondrocytes, celastrol significantly suppressed the production of inflammatory factors such as cyclooxygenase-2 (COX2), interleukin-6 (IL-6), and prostaglandin E2 (PEG2), and reduced IL-1β-induced matrix degradation by down-regulating the expression of matrix metalloproteinase 13 (MMP13). In addition, we found that toll-like receptor 2 (TLR2) was up-regulated in OA patients and rat knee OA models, while celastrol inhibited TLR2 signal and its downstream nuclear factor-kappa B (NF-κB) phosphorylation.

Conclusion: In summary, celastrol may improve OA by inhibiting the TLR2/NF-κB signaling pathway, which provides innovative strategies for the treatment of OA.

Silencing of circ_0000205 mitigates interleukin-1β-induced apoptosis and extracellular matrix degradation in chondrocytes via targeting miR-766-3p/ADAMTS5 axis

The aim of this study was to explore the role of hsa_circRNA_0000205 (circ_0000205) in chondrocyte injury in osteoarthritis (OA) and the underlying mechanism. Expression of circ_0000205, microRNA (miR)-766-3p and a disintegrin and metalloproteinase with thrombospondin motif (ADAMTS)-5 was detected by quantitative real time (qRT)-polymerase chain reaction (PCR) and Western blot assays. Cell proliferation, apoptosis, and extracellular matrix (ECM) synthesis were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and 5-ethynyl-2-deoxyuridine assays, flow cytometry, and qRT-PCR and Western blot assays. The target relationship between miR-766-3p and circ_0000205 or ADAMTS5 was confirmed by luciferase reporter assay and RNA immunoprecipitation. IL-1β treatment could attenuate cell viability of primary chondrocytes and proliferating cell nuclear antigen (PCNA) and collagen II type alpha-1 (COL2A1) levels, and elevate apoptosis rate and cleaved caspase-3, ADAMTS5 and matrix metalloproteinase-13 (MMP13) levels, suggesting that IL-1β induced chondrocyte apoptosis and ECM degradation. Expression of circ_0000205 was up-regulated in OA tissues and IL-1β-induced primary chondrocytes, accompanied with miR-766-3p down-regulation and ADAMTS5 up-regulation. Knockdown of circ_0000205 could mitigate IL-1β-induced above effects and improve cell proliferation. Moreover, both depleting miR-766-3p and promoting ADAMTS5 could partially counteract circ_0000205 knockdown roles in IL-1β-cultured primary chondrocytes. Notably, circ_0000205 was verified as a sponge for miR-766-3p via targeting, and ADAMTS5 was a direct target for miR-766-3p. Silencing circ_0000205 could protect chondrocytes from IL-1β-induced proliferation reduction, apoptosis, and ECM degradation by targeting miR-766-3p/ADAMTS5 axis.

Knockdown of circ-PRKCH alleviates IL-1β-treated chondrocyte cell phenotypic changes through modulating miR-502-5p/ADAMTS5 axis

BACKGROUND

Osteoarthritis (OA) is a common joint disease characterized by progressive cartilage degradation. Circular RNAs (circRNAs) are involved in the initiation and development of OA. This study aimed to explore the potential role and mechanism of circRNA protein kinase C eta (circ-PRKCH) in OA.

METHODS

A total of 30 cartilage specimens were collected from OA patients or normal subjects. Human chondrocytes (CHON-001) were stimulated with interleukin-1β (IL-1β) to establish an in vitro OA model. The expression levels of circ-PRKCH, microRNA-502-5p (miR-502-5p) and circ-PRKCH or A disintegrin and metalloproteases metallopeptidase with thrombospondin type 1 motif 5 (ADAMTS5) in cartilage specimens and IL-1β-treated chondrocytes were detected by quantitative real-time PCR or Western blot, and their correlation in OA cartilage specimens was analysed by Spearman's correlation coefficient. The targeted relationship between miR-502-5p and circ-PRKCH or ADAMTS5 was verified by dual-luciferase reporter assay and RNA Immunoprecipitation (RIP) assay. Cell Counting Kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EDU), flow cytometry, wound healing and enzyme-linked immunosorbent assay (ELISA) assays were applied to evaluate cell proliferation, apoptosis, migration and inflammatory response in IL-1β-treated chondrocytes. Exosomes were identified by transmission electron microscope (TEM) and Western blot.

RESULTS

Circ-PRKCH and ADAMTS5 expression levels were up-regulated, while miR-502-5p expression was down-regulated in OA cartilage tissues and IL-1β-treated chondrocytes. Depletion of circ-PRKCH relieved IL-1β-treated chondrocyte cell phenotypic changes by promoting cell proliferation and migration, as well as inhibiting apoptosis and inflammatory response. Mechanically, circ-PRKCH acted as a sponge for miR-502-5p to regulate ADAMTS5 expression, thereby contributing to IL-1β-treated chondrocyte cell phenotypic changes. Moreover, exosomes derived from IL-1β-treated chondrocytes could transfer circ-PRKCH across cells.

CONCLUSION

Circ-PRKCH contributed to IL-1β-treated cell phenotypic changes in chondrocytes via modulating miR-502-5p/ADAMTS5 pathway, which might provide a promising biomarker for OA treatment.

Circ_0043947 contributes to interleukin 1β-induced injury in chondrocytes by sponging miR-671-5p to up-regulate RTN3 expression in osteoarthritis pathology

Objective

Osteoarthritis (OA) is a chronic joint disease featured by articular cartilage degeneration and damage. Accumulating evidence have demonstrated the pivotal regulatory roles of circular RNAs in OA pathology. However, the role of circ_0043947 in OA progression and its associated mechanism remain largely unknown.

Methods

The expression of RNA and protein was determined by reverse transcription-quantitative polymerase chain reaction and Western blot assay. Cell viability was assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell proliferation was analyzed by 5-Ethynyl-2′-deoxyuridine (EdU) assay and flow cytometry. Cell apoptosis was assessed by flow cytometry. Enzyme linked immunosorbent assay was conducted to analyze the release of pro-inflammatory cytokines. Dual-luciferase reporter assay and RNA immunoprecipitation assay were performed to confirm the target interaction between microRNA-671-5p (miR-671-5p) and circ_0043947 or reticulon 3 (RTN3).

Results

Interleukin 1β (IL-1β) stimulation up-regulated the expression of circ_0043947 in chondrocytes. IL-1β treatment restrained the viability and proliferation and induced the apoptosis, extracellular matrix degradation and inflammatory response of chondrocytes partly by up-regulating circ_0043947. Circ_0043947 interacted with miR-671-5p, and miR-671-5p silencing largely reversed circ_0043947 knockdown-mediated protective effects in IL-1β-induced chondrocytes. miR-671-5p interacted with the 3′ untranslated region (3′UTR) of RTN3. miR-671-5p overexpression attenuated IL-1β-induced injury in chondrocytes, and these protective effects were largely overturned by the overexpression of RTN3. Circ_0043947 acted as a molecular sponge for miR-671-5p to up-regulate RTN3 level in chondrocytes.

Conclusion

Circ_0043947 silencing alleviated IL-1β-induced injury in chondrocytes by targeting miR-671-5p/RTN3 axis.

Circ_0110251 overexpression alleviates IL-1β-induced chondrocyte apoptosis and extracellular matrix degradation by regulating miR-3189-3p/SPRY1 axis in osteoarthritis

BACKGROUND

Mounting evidence indicates that circular RNAs (circRNAs) are involved in the progression of human diseases, including osteoarthritis (OA). In this study, we focussed on the functions and potential mechanism of circ_0110251 in OA.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine the expression of circ_0110251, collagen type XI alpha 1 chain (COL11A1), microRNA-3189-3p (miR-3189-3p) and sprouty receptor tyrosine kinase signalling antagonist 1 (SPRY1). The cyclisation analysis of circ_0110251 was analysed by RNase R and Actinomycin D assays. Flow cytometry analysis was conducted to analyse cell apoptosis. Western blot assay was used to measure the levels of extracellular matrix degradation (ECM)-associated markers and SPRY1. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull down assay were performed to analyse the relationships among circ_0110251, miR-3189-3p and SPRY1.

RESULTS

Circ_0110251 was downregulated in OA cartilage tissues and IL-1β-induced chondrocytes. IL-1β promoted the apoptosis and ECM degradation in chondrocytes, while circ_0110251 overexpression relieved the effects. Circ_0110251 functioned as the sponge for miR-3189-3p and miR-3189-3p overexpression reversed the effect of circ_0110251 on IL-1β-induced chondrocyte damage. Additionally, SPRY1 served as the target gene of miR-3189-3p. MiR-3189-3p inhibition ameliorated IL-1β-induced chondrocyte apoptosis and ECM degradation, while SPRY1 silencing rescued the impacts.

CONCLUSION

Circ_0110251 protected chondrocytes from IL-1β-induced apoptosis and ECM degradation in OA via sponging miR-3189-3p and elevating SPRY1.

Research Progress of circRNAs in Inflammatory Mechanisms of Diabetic Retinopathy: An Emerging Star with Potential Therapeutic Targets

PURPOSE

 We summarized the existing studies to elaborate the biogenesis and function of circRNAs, the effect of aberrant circRNAs expression in the mechanism of inflammation and diabetic retinopathy (DR) respectively and further explored the vital roles of circRNAs in inflammation involved in DR. Methods: We conducted a systematical literature search of abundant electronic databases (PubMed, GeneMedical and MEDLINE) up to August 2021. Results: In this review, we exhibited the biogenesis and function of circRNAs and highlighted the components of inflammatory mediators implicated in DR. Numerous circRNAs, such as circHIPK3, circZNF609, circRNA_0084043, circ_0002570, circ_0041795, circEhmt1 and circ-ITCH were discovered to play vital roles in inflammation involved in DR, which provided new ideas for diagnosis and treatment of DR. Moreover, we proposed not only the epigenetic functions of circRNAs but also novel forms of the inflammatory response, including pyroptosis, to inspire further exploration and creative research in this field. Conclusion: CircRNAs were implicated in the progression and development of inflammation in DR via aberrant expression and modulation of gene expression, serving as an emerging star with potential therapeutic targets.

New perspectives on the roles of circular RNAs in osteoarthritis development and progression (Review)

Osteoarthritis (OA) is a common disease of the elderly, posing a major personal and socioeconomic burden. OA is characterized by painful degeneration of articular cartilage, and its prevention, diagnosis and treatment remain problematic. Circular RNAs (circRNAs) constitute a large family of non-coding RNAs that are widely distributed, stable, conserved and tissue-specific. circRNAs have been found to be closely associated with OA development and progression, and they may serve as targets for disease prevention and treatment. The aim of the present article was to review the roles of circRNAs in OA and discuss possible treatment strategies.

Studies on the Role of circRNAs in Osteoarthritis

Objective

Provide a reference to elucidate the mechanism of circRNAs regulating osteoarthritis (OA) and the clinical treatment.

Methods

Herein, articles about circRNAs (hsa-circ) and osteoarthritis in the recent 5 years have been reviewed and the differential expression and regulatory effect of circRNAs in OA deduced. Based on these conclusions and Protein-Protein Interaction (PPI), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of the acquired circRNAs, the potential functions and interactions of circRNAs in OA and the involved signaling pathways are discussed.

Results

A total of 33 studies meeting the inclusion criteria were included in this study, and 27 circRNAs were upregulated and 8 circRNAs were downregulated in OA. A total of 31 circRNAs were finally included in the PPI, GO, and KEGG analyses. From PPI, 12 map nodes and 7 map edges were interrelated. VWF had the biggest node and edge size. From GO, VWF showed a majority of the functions. From KEGG, circRNAs are enriched in PI3K/AKT, human papillomavirus infection (HPI), and focal adhesion (FA) pathways, and VWF was involved in major pathways.

Conclusion

We found that most articles about circRNAs regulating OA in the recent 5 years focused on the mechanism, especially the absorption effect of circ-miRNA as sponges in the recent 2 years, while most of the articles about their functions addressed ECM and PI3K, AKT, and mTOR signaling pathways. Future studies might focus on the functions of circRNAs, and circRNA VWF, with preferable functions, interactions, and involvement, can be used as a biological indicator to detect OA in clinical practice.

IRE1 signaling regulates chondrocyte apoptosis and death fate in the osteoarthritis

IRE1 is an important central regulator of unfolded protein response (UPR) in the endoplasmic reticulum (ER) because of its ability to regulate cell fate as a function of stress sensing. When misfolded proteins accumulated in chondrocytes ER, IRE1 disintegrates with BIP/GRP78 and undergoes dimer/oligomerization and transautophosphorylation. These two processes are mediated through an enzyme activity of IRE1 to activate endoribonuclease and generates XBP1 by unconventional splicing of XBP1 messenger RNA. Thereby promoting the transcription of UPR target genes and apoptosis. The deficiency of inositol-requiring enzyme 1α (IRE1α) in chondrocytes downregulates prosurvival factors XBP1S and Bcl-2, which enhances the apoptosis of chondrocytes through increasing proapoptotic factors caspase-3, p-JNK, and CHOP. Meanwhile, the activation of IRE1α increases chondrocyte viability and reduces cell apoptosis. However, the understanding of IRE1 responses and cell death fate remains controversial. This review provides updated data about the role IRE1 plays in chondrocytes and new insights about the potential efficacy of IRE1 regulation in cartilage repair and osteoarthritis treatment.