This study aims to integrate data mining techniques of single cell transcriptomics and spatial transcriptomics, along with animal experiment validation, so as to systematically characterize the protective effects of Jianpi Tongluo Formula(JTF) on the cartilage in knee osteoarthritis(KOA) and elucidate the underlying molecular mechanisms. Single cell transcriptomics and spatial transcriptomics datasets(GSE254844 and GSE255460) of the cartilage tissue obtained from KOA patients were analyzed to map the single cell-spatial heterogeneity and identify key pathogenic factors. After that, a KOA rat model was established via knee joint injection of papain. The intervention effects of JTF on the expression features of these key factors were assessed through real-time quantitative polymerase chain reaction(PCR), Western blot, and immunohistochemical staining. As a result, the integrated single cell and spatial transcriptomics data identified distinct cell subsets with different pathological changes in different regions of the inflamed cartilage tissue in KOA, and their differentiation trajectories were closely related to the inflammatory fibrosis-like pathological changes of chondrocytes. Accordingly, the expression levels of the two key effect targets, namely nuclear receptor coactivator 4(NCOA4) and high mobility group box 1(HMGB1) were significantly reduced in the articular surface and superficial zone of the inflamed joints when JTF effectively alleviated various pathological changes in KOA rats, thus reversing the abnormal chondrocyte autophagy level, relieving the inflammatory responses and fibrosis-like pathological changes, and promoting the repair of chondrocyte function. Collectively, this study revealed the heterogeneous characteristics and dynamic changes of inflamed cartilage tissue in different regions and different cell subsets in KOA patients. It is worth noting that NCOA4 and HMGB1 were crucial in regulating chondrocyte autophagy and inflammatory reaction, while JTF could reverse the regulation of NCOA4 and HMGB1 and correct the abnormal molecular signal axis in the target cells of the inflamed joints. The research can provide a new research idea and scientific basis for developing a personalized therapeutic schedule targeting the spatiotemporal heterogeneity characteristics of KOA.
Animals ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Osteoarthritis, Knee/pathology* ; Humans ; Male ; Cartilage, Articular/metabolism* ; Chondrocytes/metabolism* ; Rats, Sprague-Dawley ; Female ; Protective Agents/administration & dosage* ; Single-Cell Analysis ; Middle Aged ; HMGB1 Protein/metabolism*

The progressive destruction of condylar cartilage is a hallmark of the temporomandibular joint (TMJ) osteoarthritis (OA); however, its mechanism is incompletely understood. Here, we show that Kindlin-2, a key focal adhesion protein, is strongly detected in cells of mandibular condylar cartilage in mice. We find that genetic ablation of Kindlin-2 in aggrecan-expressing condylar chondrocytes induces multiple spontaneous osteoarthritic lesions, including progressive cartilage loss and deformation, surface fissures, and ectopic cartilage and bone formation in TMJ. Kindlin-2 loss significantly downregulates the expression of aggrecan, Col2a1 and Proteoglycan 4 (Prg4), all anabolic extracellular matrix proteins, and promotes catabolic metabolism in TMJ cartilage by inducing expression of Runx2 and Mmp13 in condylar chondrocytes. Kindlin-2 loss decreases TMJ chondrocyte proliferation in condylar cartilages. Furthermore, Kindlin-2 loss promotes the release of cytochrome c as well as caspase 3 activation, and accelerates chondrocyte apoptosis in vitro and TMJ. Collectively, these findings reveal a crucial role of Kindlin-2 in condylar chondrocytes to maintain TMJ homeostasis.
Aggrecans/metabolism* ; Animals ; Cartilage, Articular/metabolism* ; Chondrocytes/pathology* ; Cytoskeletal Proteins/metabolism* ; Mice ; Muscle Proteins/metabolism* ; Osteoarthritis/pathology* ; Temporomandibular Joint/pathology*

Osteoarthritis (OA) is a prevalent joint disease with no effective treatment strategies. Aberrant mechanical stimuli was demonstrated to be an essential factor for OA pathogenesis. Although multiple studies have detected potential regulatory mechanisms underlying OA and have concentrated on developing novel treatment strategies, the epigenetic control of OA remains unclear. Histone demethylase JMJD3 has been reported to mediate multiple physiological and pathological processes, including cell differentiation, proliferation, autophagy, and apoptosis. However, the regulation of JMJD3 in aberrant force-related OA and its mediatory effect on disease progression are still unknown. In this work, we confirmed the upregulation of JMJD3 in aberrant force-induced cartilage injury in vitro and in vivo. Functionally, inhibition of JMJD3 by its inhibitor, GSK-J4, or downregulation of JMJD3 by adenovirus infection of sh-JMJD3 could alleviate the aberrant force-induced chondrocyte injury. Mechanistic investigation illustrated that aberrant force induces JMJD3 expression and then demethylates H3K27me3 at the NR4A1 promoter to promote its expression. Further experiments indicated that NR4A1 can regulate chondrocyte apoptosis, cartilage degeneration, extracellular matrix degradation, and inflammatory responses. In vivo, anterior cruciate ligament transection (ACLT) was performed to construct an OA model, and the therapeutic effect of GSK-J4 was validated. More importantly, we adopted a peptide-siRNA nanoplatform to deliver si-JMJD3 into articular cartilage, and the severity of joint degeneration was remarkably mitigated. Taken together, our findings demonstrated that JMJD3 is flow-responsive and epigenetically regulates OA progression. Our work provides evidences for JMJD3 inhibition as an innovative epigenetic therapy approach for joint diseases by utilizing p5RHH-siRNA nanocomplexes.
Cartilage, Articular/pathology* ; Chondrocytes/metabolism* ; Down-Regulation ; Epigenesis, Genetic ; Humans ; Jumonji Domain-Containing Histone Demethylases/metabolism* ; Nuclear Receptor Subfamily 4, Group A, Member 1/metabolism* ; Osteoarthritis/pathology* ; RNA, Small Interfering/pharmacology*

Osteoarthritis (OA) is a prevalent degenerative joint disease characterized by cartilage loss and accounts for a major source of pain and disability worldwide. However, effective strategies for cartilage repair are lacking, and patients with advanced OA usually need joint replacement. Better comprehending OA pathogenesis may lead to transformative therapeutics. Recently studies have reported that exosomes act as a new means of cell-to-cell communication by delivering multiple bioactive molecules to create a particular microenvironment that tunes cartilage behavior. Specifically, exosome cargos, such as noncoding RNAs (ncRNAs) and proteins, play a crucial role in OA progression by regulating the proliferation, apoptosis, autophagy, and inflammatory response of joint cells, rendering them promising candidates for OA monitoring and treatment. This review systematically summarizes the current insight regarding the biogenesis and function of exosomes and their potential as therapeutic tools targeting cell-to-cell communication in OA, suggesting new realms to improve OA management.
Apoptosis ; Cartilage/pathology* ; Cartilage, Articular/metabolism* ; Cell Communication ; Chondrocytes/metabolism* ; Exosomes/pathology* ; Humans ; Osteoarthritis/therapy*

Articular cartilage is a connective tissue consisting of a specialized extracellular matrix (ECM) that dominates the bulk of its wet and dry weight. Type II collagen and aggrecan are the main ECM proteins in cartilage. However, little attention has been paid to less abundant molecular components, especially minor collagens, including type IV, VI, IX, X, XI, XII, XIII, and XIV, etc. Although accounting for only a small fraction of the mature matrix, these minor collagens not only play essential structural roles in the mechanical properties, organization, and shape of articular cartilage, but also fulfil specific biological functions. Genetic studies of these minor collagens have revealed that they are associated with multiple connective tissue diseases, especially degenerative joint disease. The progressive destruction of cartilage involves the degradation of matrix constituents including these minor collagens. The generation and release of fragmented molecules could generate novel biochemical markers with the capacity to monitor disease progression, facilitate drug development and add to the existing toolbox for in vitro studies, preclinical research and clinical trials.
Aggrecans ; chemistry ; genetics ; metabolism ; Animals ; Biomarkers ; metabolism ; Cartilage, Articular ; chemistry ; metabolism ; pathology ; Collagen ; chemistry ; classification ; genetics ; metabolism ; Extracellular Matrix Proteins ; chemistry ; genetics ; metabolism ; Gene Expression ; Humans ; Osteoarthritis ; diagnosis ; genetics ; metabolism ; pathology ; Protein Isoforms ; chemistry ; classification ; genetics ; metabolism

OBJECTIVETo investigate the protective effect of LR-90 on articular cartilage in rabbit model of osteoarthritis.

METHODSThe cultured rabbits chondrocytes were assigned to be treated with IL-1β (10ng/ml) or IL-1β (10ng/ml)+LR-90 (50 mg/L). The mRNA expression of MMP-13, ADAMTS-5, aggrecan and collagen II in chondrocytes were assessed by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). Twenty male New Zealand white rabbits underwent bilateral anterior cruciate ligament transection (ACLT) to establish a animal model of osteoarthritis. Four weeks after model established, on the basis of randomization one knee of each rabbit was treated with 50 mg/L LR-90 in normal saline (NS) (experimental group) and the other knee was treated with same volume of NS (control group), 1/week × 5. Nine weeks after ACLT all rabbits were sacrificed and the knee joints were evaluated by gross morphology and histology. The mRNA expression of IL-1β, MMP-13, ADAMTS-5, aggrecan and collagen Ⅱ in articular cartilage was analyzed by RT-PCR.

RESULTSGross morphology and Mankin histological evaluation showed that the extent and grade of cartilage damage in the experimental group were less severe than those in the control group.Compared to IL-1β group, LR-90 treatment suppressed the mRNA expression of MMP-13 and ADAMTS-5, and enhanced aggrecan and collagen Ⅱ mRNA expression. Consistent with the in vitro results, the intraarticular LR-90 administration suppressed the mRNA expression of IL-1β,MMP-13 and ADAMTS-5 (all P<0.01), while enhanced mRNA expression of aggrecan and collagen Ⅱ in cartilage (all P<0.01).

CONCLUSIONLR-90 protects against cartilage degradation and inhibits the progression of osteoarthritis in rabbit mode1 of osteoarthritis, which is associated with the suppressing IL-1β, MMP-13, ADAMTS-5 and promoting aggrecan and collagen Ⅱ mRNA expression in cartilage.

ADAM Proteins ; metabolism ; Aggrecans ; metabolism ; Animals ; Anterior Cruciate Ligament ; surgery ; Butyrates ; pharmacology ; Cartilage, Articular ; metabolism ; pathology ; Cells, Cultured ; Chondrocytes ; metabolism ; Collagen Type II ; metabolism ; Disease Models, Animal ; Injections, Intra-Articular ; Interleukin-1beta ; pharmacology ; Male ; Matrix Metalloproteinase 13 ; metabolism ; Osteoarthritis ; drug therapy ; Rabbits

OBJECTIVETo investigate the effect of eletroacupuncture with close-to-bone needling treatment on expression of Sox9, vascular endothelial growth factor (VEGF) and type X collagen (ColX) in impaired cartilage of rabbits with knee osteoarthritis (KOA) and explore its possible mechanisms.

METHODSForty New Zealand rabbits were randomized equally into normal control group, KOA model group, eletroacupuncture with close-to-bone needling group (CN group), and normal thrust needing group (NTN group). In the latter 3 groups, KOA was induced by Hulth-Telhag treatment and evaluated with X-ray examination, and 6 weeks after the modeling, eletroacupuncture for 20 min was administered in CN and NTN groups at the acupoints "Zusanli", "Waixiyan", "Neixiyan", "Liangqiu" and "Yinlingquan" in the left knee joints once daily for 5 days as a treatment cycle. After 5 treatment cycles, the rabbits were examined for behavioral changes, cartilage morphology, and Mankin scores; The protein and mRNA expressions of S0x9, VEGF, and ColX were examined using Westen blotting, immunohistochemistry, and RT-PCR as appropriate.

RESULTSThe rabbits in the model, CN and NTN groups showed significant changes in behaviors and cartilage histomorphology after the modeling and after the treatments. HE staining showed that cartilage injury was repaired and tended to recovery in CN and NTN groups. The cartilage pathologies was severer in the model group than in the normal control, CN and NTN groups (P<0.01); Sox9 protein increased and VEGF mRNA level decreased in CN and NTN groups after treatment as compared with those in the model group (P<0.01).

CONCLUSIONEletroacupuncture with close-to-bone needling can effectively improve KOA in rabbits probably by enhancing Sox9 and reducing VEGF and ColX expressions in the cartilage to inhibit hypertrophic differentiation of the chondrocytes, maintain chondrogenic phenotype and repair cartilage cells.

Acupuncture Points ; Animals ; Cartilage, Articular ; metabolism ; pathology ; Cell Differentiation ; Chondrocytes ; cytology ; Chondrogenesis ; Collagen Type X ; metabolism ; Electroacupuncture ; Knee Joint ; physiopathology ; Osteoarthritis, Knee ; therapy ; Rabbits ; SOX9 Transcription Factor ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism

OBJECTIVETo establish a model of chondrocyte degeneration in vitro.

METHODSChondrocytes were isolated from articular cartilages of newly born SD rats by digestion with typeⅡ collagenase. The chondrocytes were cultured with H-DMEM medium containing 10%FBS, 50 ng/mL IL-1β+10%FBS, 2.5% rat serum and 5% rat serum, respectively; and the chondrocytes at passage one were used in the experiments. The morphology changes were investigated under phase contrast microscope after chondrocytes were treated with rat serum and IL-1β. Proliferation of chondrocytes was detected by MTT method. The protein expression levels of PCNA, typeⅡ collagen and MMP-13 were examined by Western blotting. The levels of ADAMTS5, MMP-9, Aggrecan and SOX-9 mRNA were detected by real-time PCR.

RESULTSThe cell morphology was changed from polygon to spindle in both rat serum groups and IL-1β group, and the proliferation of chondrocytes in these groups was much higher than that in control group. The results showed that the expression levels of typeⅡ collagen, Aggrecan and SOX-9 decreased while the expression levels of MMP-13, MMP-9 and ADMATS5 were up-regulated in rat serum and IL-1β-treated groups compared with control group.

CONCLUSIONThe results indicate that rat serum can induce chondrocyte degeneration and may be used for osteoarthritis model in vitro.

ADAM Proteins ; metabolism ; ADAMTS5 Protein ; Aggrecans ; metabolism ; Animals ; Cartilage, Articular ; cytology ; Cells, Cultured ; Chondrocytes ; pathology ; Collagen Type II ; metabolism ; Disease Models, Animal ; Interleukin-1beta ; pharmacology ; Matrix Metalloproteinase 13 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Osteoarthritis ; pathology ; Proliferating Cell Nuclear Antigen ; metabolism ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley ; SOX9 Transcription Factor ; metabolism ; Serum ; Up-Regulation

OBJECTIVETo compare the expressions of programmed cell death 5 (PDCD5) and early growth response protein-1 (EGR-1) in the articular cartilage between Kashin-Beck disease (KBD) and primary osteoarthritis and the roles of these factors in KBD cartilage.

METHODSCartilage specimens were collected from 10 confirmed KBD patients, 15 osteoarthritic patients and 6 healthy subjects. The expression levels of PDCD5 and EGR-1 in the cartilage were detected by immunohistochemistry staining, and the positive chondrocyte counts were recorded in the different layers of KBD and OA cartilages.

RESULTSThe KBD cartilages contained a significantly higher percentage of PDCD5-positive chondrocytes in the middle layer [(41.35 ± 2.97)%] than OA cartilages [(26.48 ± 2.04)%, P=0.001] and normal cartilages [(19.02 ± 1.88)%, P=0.000] with also obvious PDCD5 over-expression in the deeper layer compared to OA (P=0.000) and normal cartilages (P=0.029), but PDCD5 expression in the superficial layer of the cartilages showed no significant difference among the 3 groups(P>0.05). The average EGR-1 positivity rate in the superficial layer of the cartilage was significantly higher in KBD patients than in OA patients (P=0.000) and healthy controls (P=0.000), but in the middle layer, its positivity rate in KBD patients was higher than that in the normal control (P=0.017) but lower than that of OA cartilage (P=0.002); EGR-1 expression in the deeper layer was comparable in KBD and OA cartilages but both was higher than that in normal cartilages. PDCD5 and EGR-1 expressions were not correlated in either KBD or normal cartilages, but were positively correlated in the superficial layer of OA cartilages.

CONCLUSIONSKBD cartilages show a significantly increased PDCD5 expression in the deeper layer and enhanced EGR-1 expression in both superficial and deeper layers, suggesting the involvement of PDCD5 and EGR-1 in the pathogenesis of KBD.

Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Cartilage, Articular ; metabolism ; pathology ; Chondrocytes ; metabolism ; Early Growth Response Protein 1 ; metabolism ; Humans ; Immunohistochemistry ; Kashin-Beck Disease ; metabolism ; Neoplasm Proteins ; metabolism ; Osteoarthritis ; metabolism ; Transcriptome

OBJECTIVETo evaluate the effects of treadmill running exercise of different intensity on early repair of full-thickness defects on the patellofemoral articular surface and the changes in the expressions of matrix metalloproteinase-3 (MMP-3) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in SD rats.

METHODSTwenty-four male SD rats with full-thickness defects on the patellofemoral articular surface were randomly assigned into sedentary control (SED) group and low-, moderate- and high-intensity running groups (LIR, MIR, and HIR groups, respectively). The running groups were trained on treadmill for 6 consecutive weeks. Blood samples were collected to detect serum MMP-3 and TIMP-1 levels using ELISA before and after the experiment, and the femoral trochlea were collected to assess tissue repair by gross appearance scoring and O Driscoll histological scoring with Safranine O-Fast Green staining and Toluidine blue staining.

RESULTSIn rats in SED group, the defect was filled with hyaline articular cartilage-like tissues, as compared to fibrous tissues in LIR and MIR groups and subchondral bone damage in HIR group. The SED group scored the highest and HIR group the lowest among the 4 groups in gross appearance scoring and O Driscoll histological scoring. No significant differences were found in MMP-3 or TIMP-1 levels among the groups before training (P>0.05), but after 6 weeks of training, serum MMP-3 and TIMP-1 levels differed significantly among the 4 groups (P<0.05), and all the 3 running groups had a significantly higher MMP-3 level than the control group (P<0.05). After the 6-week training, TIMP-1/MMP-3 ratio was significantly higher in SED group than in the 3 running groups, and was the lowest in HIR group.

CONCLUSIONBoth low- and moderate-intensity exercise failed to promote resurfacing of full-thickness cartilage defects on the patellofemoral articular surface in rats, and high-intensity exercise even induces subchondral bone damage. The expression of MMP-3 and TIMP-1 is related to exercise, and the TIMP-1/MMP-3 ratio reflects the extent of tissue repair.

Animals ; Cartilage, Articular ; metabolism ; pathology ; Male ; Matrix Metalloproteinase 1 ; metabolism ; Matrix Metalloproteinase 3 ; metabolism ; Physical Conditioning, Animal ; Rats ; Rats, Sprague-Dawley ; Tissue Inhibitor of Metalloproteinase-1 ; metabolism ; Wound Healing