Project description:Knee osteoarthritis (KOA), as a degenerative multifactorial disease, affects the quality of life and mental health of patients, and also brings a huge socioeconomic burden. Treating synovitis have shown promise as anti-inflammatory therapeutics in mitigating OA symptoms and disease progression. Here, by analysing synovial single-cell sequencing (scRNA-seq) data from KOA, we found that synovial fibroblasts (FLS) in OA synovium showed a distinct pro-inflammatory phenotype. We collected synovial tissue from patients with clinical OA as well as from healthy donors, and histological examination was consistent with findings in scRNA-seq. Inspired by recent cross-tissue fibroblast lineage studies, we identified by sequencing that healthy FLS in synovial tissues share transcriptome-level similarities with dermal fibroblasts (DFb). Subsequently, we revealed the local as well as systemic distribution of intra-articular injected DFbs by constructing/extracting two types of rat fibroblasts (luciferase DFbs as well as GFP DFbs). The results demonstrate that DFbs can be locally retained in the synovium for up to three weeks following targeted engrafting on it. And intra-articular injection does not result in DFbs migration to vital organs or the occurrence of histological changes in these organs. A rat model of KOA was constructed by anterior cruciate ligament transection (ACLT) in order to study the therapeutic effect of DFbs on KOA. After injection, the rats showed improvement in painful gait. In addition, histological as well as imaging results showed reduced synovitis and improvement in articular cartilage. Finally we verified the protective effect of DFbs on cytokine-stimulated chondrocytes in a co-culture system.
Project description:Knee osteoarthritis (KOA), as a degenerative multifactorial disease, affects the quality of life and mental health of patients, and also brings a huge socioeconomic burden. Treating synovitis have shown promise as anti-inflammatory therapeutics in mitigating OA symptoms and disease progression. Here, by analysing synovial single-cell sequencing (scRNA-seq) data from KOA, we found that synovial fibroblasts (FLS) in OA synovium showed a distinct pro-inflammatory phenotype. We collected synovial tissue from patients with clinical OA as well as from healthy donors, and histological examination was consistent with findings in scRNA-seq. Inspired by recent cross-tissue fibroblast lineage studies, we identified by sequencing that healthy FLS in synovial tissues share transcriptome-level similarities with dermal fibroblasts (DFb). Subsequently, we revealed the local as well as systemic distribution of intra-articular injected DFbs by constructing/extracting two types of rat fibroblasts (luciferase DFbs as well as GFP DFbs). The results demonstrate that DFbs can be locally retained in the synovium for up to three weeks following targeted engrafting on it. And intra-articular injection does not result in DFbs migration to vital organs or the occurrence of histological changes in these organs. A rat model of KOA was constructed by anterior cruciate ligament transection (ACLT) in order to study the therapeutic effect of DFbs on KOA. After injection, the rats showed improvement in painful gait. In addition, histological as well as imaging results showed reduced synovitis and improvement in articular cartilage. Finally we verified the protective effect of DFbs on cytokine-stimulated chondrocytes in a co-culture system.
Project description:Osteoarthritis (OA) is a serious degenerative joint disease with high morbidity and is currently incurable because of its poorly defined underlying molecular basis. Here, we demonstrated that Tiki2, a membrane-tethered proteolytic Wnt inhibitor, is highly expressed in the articular chondrocytes of hyaline cartilage and that its expression negatively correlates with osteoarthritis. Tiki2 haploinsufficiency in mice causes spontaneous articular cartilage degeneration. Tiki2 deletion in chondrocytes accelerates instability-induced knee joint osteoarthritis progression in mice. Mechanistically, Tiki2 antagonizes Wnt signaling in chondrocytes and maintains chondrocyte anabolic gene expression. Moreover, intra-articular administration of a TIKI2-expressing adeno-associated virus significantly alleviated OA progression in mice, and expressing TIKI2 promoted chondrogenesis and chondrocyte redifferentiation and inhibited hypertrophic differentiation in vitro. Our results reveal the function of Tiki2 in articular cartilage homeostasis and osteoarthritis and suggest that Tiki2 is a potential target for osteoarthritis therapy.
Project description:The regeneration of diseased hyaline cartilage remains a great challenge, mainly because degeneration activities after major injury or due to age-related processes overwhelm the self-renewal capacity of the tissue. We show that repair tissue from human articular cartilage of late stages of osteoarthritis harbor a unique progenitor cell population, termed chondrogenic progenitor cells exhibiting stem cell characteristics, such as multipotency, lack of immune system activation and, in particular, migratory activity. The isolated CPC exhibit a high chondrogenic potential and were able to populate diseased tissue in vivo. Moreover, down-regulation of the osteogenic transcription factor runx-2 enhanced the expression of the chondrogenic transcription factor sox-9 and consequently the matrix synthesis potential of chondrogenic progenitor cells. Our results, while offering new insight into the biology of progenitor cells from diseased cartilage tissue, might assist future strategies to treat late stages of osteoarthritis. Experiment Overall Design: Characterization chondrogenic progenitor cells in P1 of 3 male and 3 female patients with late-stage OA in comparison to healthy chondrocytes in P1
Project description:Cell senescence is a driver of various aging-associated disorders including osteoarthritis. Here, we identified a critical role for Yes-associated protein (YAP), a major effector of Hippo signaling, in maintaining a younger state of human mesenchymal stem cells (MSCs) and ameliorating osteoarthritis in mice. Targeted knockout of YAP in hMSCs resulted in premature cellular senescence. Mechanistically, YAP interacted with TEA domain transcriptional factor (TEAD) to activate forkhead box D1 (FOXD1) expression. YAP deficiency led to the downregulation of FOXD1, a geroprotective protein. In turn, overexpression of YAP or FOXD1 rejuvenated aged hMSCs. Moreover, intra-articular administration of lentiviral vectors encoding YAP or FOXD1 attenuated the development of osteoarthritis in mice. Collectively, our findings reveal YAP-FOXD1, a novel aging-associated regulatory axis, as a potential therapeutic target for gene therapy to alleviate osteoarthritis.
Project description:Sox2 is required to maintain osteosarcoma cell tumor initiation.Knockdown of Sox2 leads tpo loss of tumorigenic properties. To examine gene expression changes upon Sox2 knockdown, we performed microarray analysis on mouse osteosarcoma cells expressing scrambled or Sox2shRNA. We found that genes upregulated upon Sox2 knockdown included osteoblast diffrentiation genes and genes down regulated included cell cycle and RNA processing genes as well as YAP-TEAD target genes. The Hippo pathway has a profound tumor suppressive role in cancer by restraining the strong growth-promoting function of YAP. We have previously shown that the stem cell transcription factor Sox2 maintains the tumorigenicity of osteosarcoma cancer stem cells (CSCs). In this report, we describe that Sox2 maintains stemness by antagonizing the Hippo pathway via direct repression of Hippo activators, Nf2 (Merlin) and WWC1 (Kibra), thereby leading to exaggerated YAP function. YAP is potently oncogenic in osteosarcoma and its depletion sharply reduces the tumorigenic CSC fraction. Low Nf2, low WWC1, and high YAP expression mark the CSC fraction of the tumor population, while the more differentiated fraction has high Nf2, high WWC1 and reduced YAP expression. This Sox2-Hippo axis is conserved and also operates in other Sox2-dependent cancers such as glioblastomas. We propose that disruption of YAP transcriptional activity reduces CSCs and could be a therapeutic strategy for Sox2- dependent tumors. Gene expression of 482 mouse lines mOS482 were analyzed by microarray. 3 replicates each of scrambled and Sox2shRNA were processed and hybridized
Project description:Progressive loss of tissue homeostasis hallmarks numerous age-related pathologies. By using parabiosic approaches in animal models, recent evidences demonstrate that age-regulated geronic factors such as GDF11 or CCL11 could widely control positively or negatively tissue homeostasis. Here we evaluated the impact of the first identified anti-geronic hormone a-Klotho on tissue homeostasis taken articular cartilage and osteoarthritis (OA) as studying models. We show that a-Klotho is secreted during an in vitro induced chondrogenesis of osteo-chondral stem cells. Expression of a-Klotho is reduced in both cartilage of OA patients compared to healthy donors and in cartilage of OA murine models. Gain and loss of function experiments followed by a genome-wide gene array analysis identified Nos2-Zip8-MMP13 catabolic axis as repressed in OA chondrocytes upon a-Klotho treatment. Accordingly, intra-articular delivery of secreted a-klotho delays cartilage loss of functions in experimental OA mouse models thus revealing a novel chondroprotective function for this anti-geronic hormone.
Project description:The regeneration of diseased hyaline cartilage remains a great challenge, mainly because degeneration activities after major injury or due to age-related processes overwhelm the self-renewal capacity of the tissue. We show that repair tissue from human articular cartilage of late stages of osteoarthritis harbor a unique progenitor cell population, termed chondrogenic progenitor cells exhibiting stem cell characteristics, such as multipotency, lack of immune system activation and, in particular, migratory activity. The isolated CPC exhibit a high chondrogenic potential and were able to populate diseased tissue in vivo. Moreover, down-regulation of the osteogenic transcription factor runx-2 enhanced the expression of the chondrogenic transcription factor sox-9 and consequently the matrix synthesis potential of chondrogenic progenitor cells. Our results, while offering new insight into the biology of progenitor cells from diseased cartilage tissue, might assist future strategies to treat late stages of osteoarthritis. Keywords: cell type comparison