Articular chondrocyte inflammation- and senescence- related gene expression is altered with mitochondrial inhibition and in non-physiologic culture conditions
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ABSTRACT: Avascular soft tissues of the skeletal system, including articular cartilage, have an extremely limited healing capacity, in part due to their low metabolic activity. No drugs are available that can prevent or slow the development of osteoarthritis (OA) after joint injury. Therefore, mesenchymal stromal cell (MSC)-based regenerative therapies are increasingly common in the treatment of OA, but questions regarding their clinical efficacy and mechanisms of action remain unanswered. Our group recently reported that mitochondrial dysfunction is one of the earliest responses of cartilage to injury, resulting in chondrocyte death, extracellular matrix degeneration, and ultimately OA. MSCs have been found to rescue injured cells and improve healing by donating healthy mitochondria in highly metabolic tissues, but mitochondrial transfer has not been investigated in cartilage. To investigate how gene expression changes in stressed chondrocytes, and therefore how they might elicit mitochondrial donation from MSCs, we developed a custom quantitative PCR panel of relevant genes involved in chondrocyte metabolism and OA. We cultured chondrocytes under conditions known induce chondrocyte mitochondrial dysfunction, including stimulation with rotenone/antimycin and non-physiologic culture conditions (hyperoxia and hyperglycemia). We found that expression of gap junction alpha 1 (GJA1), the gene that encodes the Cx43 protein, was increased in hyperoxia. The senescence associated markers, cyclin-dependent kinase inhibitor 2A (CDKN2A) and tissue inhibitor of metalloproteinases 1 (TIMP1), were also increased in hyperoxia. In addition, hyperoxia caused chondrocytes to increase the expression of the antioxidant enzyme, SOD2. This work provides insights into the chemical and environmental conditions that can alter gene expression in chondrocytes. Further, this provides supporting evidence to our hypothesis that stressed chondrocytes may trigger mitochondrial donation from MSCs may via direct or indirect signaling involving the inflammation- and senescence-related genes identified in the present study.
ORGANISM(S): Mus
PROVIDER: GSE202788 | GEO | 2022/08/10
REPOSITORIES: GEO
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