Extracellular Matrix Catabolism Research Articles

Injectable self-healing hydrogel with siRNA delivery property for sustained STING silencing and enhanced therapy of intervertebral disc degeneration

Inflammatory responses of nucleus pulposus (NP) can induce imbalanced anabolism and catabolism of extracellular matrix, and the cytosolic dsDNA accumulation and STING–NF–κB pathway activation found in NP inflammation are considered as fairly important cause of intervertebral disc (IVD) degeneration. Herein, we constructed a siSTING delivery hydrogel of aldehyde hyaluronic acid (HA-CHO) and poly(amidoamine) PAMAM/siRNA complex to intervene the abnormal STING signal for IVD degeneration treatment, where the formation of dynamic Schiff base bonds in the system (siSTING@HPgel) was able to overcome the shortcomings such as low cellular uptake, short half-life, and rapid degradation of siRNA-based strategy. PAMAM not only formed complexes with siRNA to promote siRNA transfection, but also served as dynamic crosslinker to construct hydrogel, and the injectable and self-healing hydrogel efficiently and steadily silenced STING expression in NP cells. Finally, the siSTING@HPgel significantly eased IVD inflammation and slowed IVD degeneration by prolonging STING knockdown in puncture-induced IVD degeneration rat model, revealing that STING pathway was a therapeutic target for IVD degeneration and such novel hydrogel had great potential for being applied to many other diseases for gene delivery.

Small molecule natural compound targets the NF-κB signaling and ameliorates the development of osteoarthritis.

Osteoarthritis (OA) is a multifactorial and chronic disease describing the destruction of cartilage that can lead to defects in the elderly. There is currently no practical strategy that can reverse the OA process. Here, we describe nepetin, a small natural compound with extracellular matrix (ECM) and inflammation regulating functions. In this study, we investigated the therapeutic effects of nepetin on interleukin-1β (IL-1β)-induced inflammation in mice chondrocyte and OA model. In chondrocytes, treatment with nepetin inhibited the overexpression of pro-inflammatory cytokines and mediators induced by IL-1β. Moreover, pretreatment or posttreatment with nepetin also reduced the ECM catabolism and enhanced the ECM anabolism. Mechanistically, nepetin suppressed NF-κB signaling pathway in IL-1β stimulated chondrocyte. Meanwhile, our molecular docking studies indicated nepetin had a powerful binding capacity to p65. Furthermore, nepetin showed a protective and therapeutic effect on the mouse OA model. To sum up, this study indicated nepetin had a new potential therapeutic option in OA.

Dehydrocostus Lactone Attenuates the Senescence of Nucleus Pulposus Cells and Ameliorates Intervertebral Disc Degeneration via Inhibition of STING-TBK1/NF-κB and MAPK Signaling.

The progression of intervertebral disc degeneration (IDD) is multifactorial with the senescence of nucleus pulposus (NP) cells and closely related to inflammation in NP cells. Dehydrocostus lactone (DHE) is a natural sesquiterpene lactone isolated from medicinal plants that has anti-inflammatory properties. Thus, DHE may have a therapeutic effect on the progression of IDD. In this study, NP cells were used to determine the appropriate concentration of DHE in vitro. The role of DHE in tumor necrosis factor-α (TNF-α)–induced activation of inflammatory signaling pathways and cellular senescence, together with anabolism and catabolism of extracellular matrix (ECM) in NP cells, was examined in vitro. The therapeutic effect of DHE in vivo was determined using a spinal instability model of IDD in mice. The TNF-α–induced ECM degradation and the senescence of NP cells were partially attenuated by DHE. Mechanistically, DHE inhibited the activation of NF-κB and MAPK inflammatory signaling pathways and ameliorated the senescence of NP cells caused by the activation of STING-TBK1/NF-κB signaling induced by TNF-α. Furthermore, a spinal instability model in mice demonstrated that DHE treatment could ameliorate progression of IDD. Together, our findings indicate that DHE can alleviate IDD changes and has a potential therapeutic function for the treatment of IDD.

Inhibition of Autophagy at Different Stages by ATG5 Knockdown and Chloroquine Supplementation Enhances Consistent Human Disc Cellular Apoptosis and Senescence Induction rather than Extracellular Matrix Catabolism

The intervertebral disc is the largest avascular organ. Autophagy is an important cell survival mechanism by self-digestion and recycling damaged components under stress, primarily nutrient deprivation. Resident cells would utilize autophagy to cope with the harsh disc environment. Our objective was to elucidate the roles of human disc cellular autophagy. In human disc cells, serum deprivation and pro-inflammatory interleukin-1β (IL-1β) stimulation increased autophagy marker microtubule-associated protein 1 light chain 3 (LC3)-II and decreased autophagy substrate p62/sequestosome 1 (p62/SQSTM1), indicating enhanced autophagy. Then, RNA interference (RNAi) of autophagy-related gene 5 (ATG5), essential for autophagy, showed decreases in ATG5 protein (26.8%–27.4%, p < 0.0001), which suppressed early-stage autophagy with decreased LC3-II and increased p62/SQSTM1. Cell viability was maintained by ATG5 RNAi in serum-supplemented media (95.5%, p = 0.28) but reduced in serum-free media (80.4%, p = 0.0013) with IL-1β (69.9%, p = 0.0008). Moreover, ATG5 RNAi accelerated IL-1β-induced changes in apoptosis and senescence. Meanwhile, ATG5 RNAi unaffected IL-1β-induced catabolic matrix metalloproteinase release, down-regulated anabolic gene expression, and mitogen-activated protein kinase pathway activation. Lysosomotropic chloroquine supplementation presented late-stage autophagy inhibition with apoptosis and senescence induction, while catabolic enzyme production was modest. Disc-tissue analysis detected age-related changes in ATG5, LC3-II, and p62/SQSTM1. In summary, autophagy protects against human disc cellular apoptosis and senescence rather than extracellular matrix catabolism.

Eicosapentaenoic Acid-Induced Autophagy Attenuates Intervertebral Disc Degeneration by Suppressing Endoplasmic Reticulum Stress, Extracellular Matrix Degradation and Apoptosis: An &lt;i&gt;in vivo&lt;/i&gt; and &lt;i&gt;in vitro&lt;/i&gt; Experiment

Background: Intervertebral disc degeneration (IDD) is a major cause of low back pain (LBP), and effective therapies are still lacking. Many previous studies have shown that endoplasmic reticulum stress (ER-stress) and extracellular matrix (ECM) degradation play an important role in the development of IDD. Autophagy can effectively repair endoplasmic reticulum stress and maintain ECM homeostasis. Eicosapentaenoic Acid (EPA) can specifically induce autophagy. Methods: Western blotting, immunofluorescence staining, and confocal microscope assay were applied to demonstrate the molecular mechanism of EPA in the nucleus pulposus cells (NPCs) in vitro. The therapeutic potential of EPA was investigated using puncture-induced rat models in vivo. Findings: EPA can effectively activate the autophagy intensity in NPCs, inhibit the progress of ER-stress, and reduce the degree of apoptosis and made the protective effects on the anabolism and catabolism of ECM. Further in vivo investigation demonstrated that EPA ameliorated the progression of puncture-induced IDD in rats. Interpretation: This finding reveals the intrinsic mechanism of EPA's protective role in NPCs and its potential therapeutic value in the treatment of IDD. Funding: This study is funded by Wenzhou Science and Technology Bureau Foundation (20180031). Declaration of Interest: None to declare. Ethical Approval: The animal use and care protocols were strictly adhered to according to the guidelines approved by Wenzhou Medical University Animal Care and Use Committee.

Circular RNA CircCDH13 contributes to the pathogenesis of osteoarthritis via CircCDH13/miR-296-3p/PTEN axis.

Circular RNAs (circRNAs) are involved in a variety of human diseases; however, the function of circRNAs in osteoarthritis (OA) remains largely unknown. In this study, we investigated the role of CircCDH13 in OA and its underlying mechanisms. CircRNA expression profiles in OA and normal cartilage tissues were detected by microarray. The expression pattern, functional role, and mechanisms of CircCDH13 in OA were studied in vitro and in vivo. Gain-of-function and loss-of-function approaches were used to demonstrate the participation of CircCDH13 in OA. The regulatory relationship between CircCDH13 and miR-296-3p andmiR-296-3pand phosphatase and tensin homolog (PTEN) was predicted by bioinformaticsand verified by RNA pulldown and luciferase assay. Adeno-associated virus was also used to reveal the role and mechanisms of CircCDH13 in destabilization of medial meniscus (DMM)-induced OA mice. The upregulation of CircCDH13 in OA cartilage tissues significantly induces chondrocyte apoptosis, promotes extracellular matrix (ECM) catabolism, and inhibits ECM anabolism. Mechanistically, CircCDH13 contributes to OA pathogenesis by functioning as a sponge of miR-296-3p and regulating the miR-296-3p-PTEN pathway. Silencing of CircCDH13 in vivo markedly alleviated DMM-induced OA in mice. Our study revealed an important role of CircCDH13 in OA pathogenesis. Silencing of CircCDH13 could reduce chondrocyte apoptosis, inhibit ECM catabolism, and promote ECM anabolism through the miR-296-3p-PTEN pathway. It provides a potential target for developing effective interventions in treating OA.

MiRNA-141 Induced Pyroptosis in Intervertebral Disk Degeneration by Targeting ROS Generation and Activating TXNIP/NLRP3 Signaling in Nucleus Pulpous Cells

The role and mechanism of pyroptosis in intervertebral disk (IVD) degeneration are unclear. MicroRNAs (miRNAs) regulate the viability and function of nucleus pulposus cells (NPCs) in IVDs and are related to pyroptosis. We performed microarray analyses of normal and degenerated nucleus pulposus (NP) to assess the role of pyroptosis and identify key miRNAs in IVD degeneration. We also evaluated the underlying mechanism of miRNA-mediated pyroptosis in NPCs. In addition, we demonstrated the preventative effects of miRNAs on IVD degeneration in a rat model. The levels of the pyroptosis-related proteins cleaved caspase-1, N-terminal gasdermin D (GSDMD), interleukin (IL)-1β, and IL-18 in the degenerative NP were significantly higher than those in the normal NP. miRNA-141 was significantly upregulated in the degenerated NP. miR-141 mimic suppressed the matrix synthesis function of NPCs. By contrast, reactive oxygen species (ROS) generation, and the expression of TXNIP and NLRP3 were significantly downregulated by an miR-141 inhibitor. Furthermore, the miRNA-141 inhibitor prevented the degeneration of IVDs in vivo. Our findings suggest that miRNA-141 induces pyroptosis and extracellular matrix (ECM) catabolism in NPCs by increasing ROS generation and activating TXNIP/NLRP3 signaling. miRNA-141-regulated pyroptosis may be a novel therapeutic target for IVD degeneration.

Cartilage Homeostasis Affects Femoral Head Necrosis Induced by Methylprednisolone in Broilers.

(1) Background: Since the large-scale poultry industry has been established, femoral head necrosis (FHN) has always been a major leg disease in fast-growing broilers worldwide. Previous research suggested that cartilage homeostasis could be taken into consideration in the cause of FHN, but the evidence is insufficient. (2) Methods: One-day-old broiler chickens were randomly divided into three groups, 16 broilers per group. The birds in group L were injected intramuscularly with methylprednisolone (MP) twice a week for four weeks (12.5 mg·kg−1). The birds in group H were injected intramuscularly with MP (20 mg·kg−1·d−1) for 7 d (impulse treatment). The birds in group C were treated with sterile saline as a control group. Broilers were sacrificed at 42 and 56 d. Blood samples were collected from the jugular vein for ELISA and biochemical analysis. Bone samples, including femur, tibia, and humerus, were collected for histopathological analysis, bone parameters detection, and real-time quantitative PCR detection. (3) Results: The FHN broilers in group L and H both showed lower body weight (BW) and reduced bone parameters. In addition, the MP treatment resulted in reduced extracellular matrix (ECM) anabolism and enhanced ECM catabolism. Meanwhile, the autophagy and apoptosis of chondrocytes were enhanced, which led to the destruction of cartilage homeostasis. Moreover, the impulse MP injection increased the portion of birds with severer FHN, whereas the MP injection over a long period caused a more evident change in serum cytokine concentrations and bone metabolism indicators. (4) Conclusions: The imbalance of cartilage homeostasis may play a critical role in the development of FHN in broilers. FHN broilers induced by MP showed a more pronounced production of catabolic factors and suppressed the anabolic factors, which might activate the genes of the WNT signal pathway and hypoxia-inducible factors (HIFs), and then upregulate the transcription expression of ECM to restore homeostasis.

LncRNA TRPC7-AS1 regulates nucleus pulposus cellular senescence and ECM synthesis via competing with HPN for miR-4769-5p binding

Intervertebral disc (IVD) degeneration (IDD) is identified as an abnormal, cell-mediated, age-dependent and genetics-dependent molecular degeneration process in which NPCs (nucleus pulposus cells) senesce and the balance of ECM (extracellular matrix) synthesis and catabolism is disrupted. Increasing evidence reveals that IDD can be modulated by genetic factors, including non-coding RNAs. In the present study, we downloaded non-coding RNA profiling (GSE56081 and GSE63492) and performed GO annotation and enrichment analysis and association analyses on differentially-expressed genes. LncRNA TRPC7-AS1, miR-4769−5p, and Hepsin (HPN) may form a lncRNA-miRNA-mRNA network that can regulate NPC proliferation, senescence and ECM in IDD. LncRNA TRPC7-AS1 directly targets miR-4769−5p while miR-4769−5p directly targets HPN 3′UTR. miR-4769−5p overexpression inhibited HPN expression, suppressed NPC senescence, promoted NPC viability, and promoted ECM synthesis. The effect of TRPC7-AS1 silence on NPCs was similar as miR-4769−5p overexpression while the effect of HPN overexpression was opposite to miR-4769−5p overexpression. miR-4769−5p suppression or HPN overexpression could significantly attenuate the effect of TRPC7-AS1 silence. LncRNA TRPC7-AS1 relieves miR-4769−5p-induced inhibition on HPN via acting as a ceRNA, thus regulating NPC viability, senescence, and ECM synthesis. In summary, we regard lncRNA-miRNA-mRNA modulation as a new potent target for IDD treatment.

Dickkopf-3 (DKK3) Signaling in IL-1α-Challenged Chondrocytes: Involvement of the NF-κB Pathway.

Osteoarthritis (OA) is an age-related biomechanical and low-grade inflammometabolic disease of the joints and one of the costliest and disabling forms of arthritis. Studies on matrix-degrading enzymes such as metalloproteases, which are implicated in the increased catabolism of extracellular matrix, are of paramount relevance. DKK3 is a member of DKK family and is best known for its role in cancer. Although there is some information about the participation of DKK3 in cartilage pathophysiology and on metalloproteases regulation, in particular, little is known about DKK3 signaling mechanisms. Thus, the aim of this study is to explore how DKK3 regulates matrix metalloproteinase-13 (MMP-13) expression. Gene, protein expression and protein phosphorylation in primary human chondrocytes and ATDC5 mouse cells were assessed by RT-qPCR and Western blot analysis. Further studies on DKK3 activity were performed by targeting DKK3 gene with a specific siRNA. DKK3 expression was found to be higher in OA human chondrocytes than healthy cells, being its expression decreased in interleukin-1α (IL-1α)-stimulated cells. DKK3 knockdown increased the induction of MMP-13 elicited by IL-1α in human and mouse chondrocytes and after the analysis of different signalling pathways, we observed that NF-κB pathway was involved in the regulation of MMP-13 expression by DKK3. Herein we have demonstrated, for the first time, that DKK3 gene silencing exacerbated NF-κB activation, resulting in an increased IL-1α-driven induction of MMP-13. Our results further confirm that DKK3 may play a protective role in OA by attenuating NF-κB activation and the subsequent production of metalloproteases.

Circular RNA derived from TIMP2 functions as a competitive endogenous RNA and regulates intervertebral disc degeneration by targeting miR‑185‑5p and matrix metalloproteinase 2.

Intervertebral disc degeneration (IDD) is an important cause of lower back pain, although the underlying mechanisms remain poorly understood. The present study aimed to examine the role of a circular RNA derived from tissue inhibitor of metallopeptidases 2 (circ-TIMP2) in degenerative nucleus pulposus (NP) tissues, and to validate its function in cultured human NP cells. Overexpression of miR-185-5p in NP cells markedly inhibited the enhanced extracellular matrix (ECM) catabolism induced by tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) treatment. Bioinformatics analysis demonstrated that matrix metalloproteinase 2 (MMP2) was a potential target of miR-185-5p. MMP2 protein expression levels were increased following treatment with TNF-α and IL-1β in NP cells compared with those in untreated cells, and this effect was attenuated by transfection with miR-185-5p. Compared with normal NP tissues, IDD samples exhibited higher circ-TIMP2 expression levels. In addition, overexpres-sion of circ-TIMP2 promoted ECM catabolism and suppressed ECM anabolism. Furthermore, circ-TIMP2 sequestered miR-185-5p, which may potentially upregulate the target genes associated with ECM degradation. In conclusion, the results of the present study revealed that circ-TIMP2 promoted TNF-α- and IL-1β-induced NP cell imbalance between ECM anabolism and catabolism via miR-185-5p-MMP2 signaling. These findings provide a potential therapeutic option for the treatment of IDD.

The circular RNA FAM169A functions as a competitive endogenous RNA and regulates intervertebral disc degeneration by targeting miR-583 and BTRC

Intervertebral disc degeneration (IDD) is an important factor leading to low back pain, although the underlying mechanisms remain poorly understood. In this study we examined the role of circular RNA FAM169A (circ-FAM169A) in degenerative nucleus pulposus (NP) tissues, and validated its function in cultured human NP cells. Overexpression of circ-FAM169A in NP cells markedly enhanced extracellular matrix (ECM) catabolism and suppressed ECM anabolism in NP cells. Furthermore, circ-FAM169A sequestered miR-583, which could potentially upregulate BTRC, an inducer of the NF-κB signaling pathway. In conclusion, the present study revealed that circ-FAM169A promotes IDD development via miR-583/BTRC signaling. These findings provide a potential therapeutic option for the treatment of IDD.

α-Bisabolol suppresses the inflammatory response and ECM catabolism in advanced glycation end products-treated chondrocytes and attenuates murine osteoarthritis

As a chronic musculoskeletal degeneration disease, osteoarthritis (OA) clinically manifests as joint pain, stiffness and a limited range of movement. OA has affected the life quality of at least one-tenth of the population but lacks satisfactory treatments. α-Bisabolol (BISA) is a small oily sesquiterpene alcohol widely found in essential oils of chamomile (Matricaria recutita), salvia and wood of Candeia and has multiple biological properties, particularly an anti-inflammatory effect. The purpose of this study is to assess the anti-inflammatory and chondroprotective effect of BISA in OA progression and explore its underlying mechanism. We isolated human chondrocytes and treated them with advanced glycation end products (AGEs) to imitate OA progression in vitro. BISA pretreatment suppressed the AGE-induced inflammatory reaction and extracellular matrix (ECM) degeneration by blocking nuclear factor kappa B (NF-κB), p38 and c-Jun N-terminal kinase (JNK) signaling. Moreover, a mouse destabilization of the medial meniscus (DMM) model was established by surgery to investigate BISA protection in vivo. BISA administration attenuated DMM-induced radiological and histopathological changes relative to the DMM group and resulted in lower OARSI scores. Taken together, the results of our study indicate the potential of BISA in OA therapy.

Autophagy and mTOR signaling during intervertebral disc aging and degeneration.

Degenerative disc disease is a highly prevalent, global health problem that represents the primary cause of back pain and is associated with neurological disorders, including radiculopathy, myelopathy, and paralysis, resulting in worker disability and socioeconomic burdens. The intervertebral disc is the largest avascular organ in the body, and degeneration is suspected to be linked to nutritional deficiencies. Autophagy, the process through which cells self‐digest and recycle damaged components, is an important cell survival mechanism under stress conditions, especially nutrient deprivation. Autophagy is negatively controlled by the mammalian target of rapamycin (mTOR) signaling pathway. mTOR is a serine/threonine kinase that detects nutrient availability to trigger the activation of cell growth and protein synthesis pathways. Thus, resident disc cells may utilize autophagy and mTOR signaling to cope with harsh low‐nutrient conditions, such as low glucose, low oxygen, and low pH. We performed rabbit and human disc cell and tissue studies to elucidate the involvement and roles played by autophagy and mTOR signaling in the intervertebral disc. In vitro serum and nutrient deprivation studies resulted in decreased disc cell proliferation and metabolic activity and increased apoptosis and senescence, in addition to increased autophagy. The selective RNA interference‐mediated and pharmacological inhibition of mTOR complex 1 (mTORC1) was protective against inflammation‐induced disc cellular apoptosis, senescence, and extracellular matrix catabolism, through the induction of autophagy and the activation of the Akt‐signaling network. Although temsirolimus, a rapamycin derivative with improved water solubility, was the most effective mTORC1 inhibitor tested, dual mTOR inhibitors, capable of blocking multiple mTOR complexes, did not rescue disc cells. In vivo, high levels of mTOR‐signaling molecule expression and phosphorylation were observed in human intermediately degenerated discs and decreased with age. A mechanistic understanding of autophagy and mTOR signaling can provide a basis for the development of biological therapies to treat degenerative disc disease.

Oxymatrine suppresses IL-1β-induced degradation of the nucleus pulposus cell and extracellular matrix through the TLR4/NF-κB signaling pathway.

Intervertebral disc degeneration is the main cause of low back pain. However, its pathomechanism has not been fully clarified yet. Previous studies have indicated that inflammation may lead to apoptosis of nucleus pulposus cells and break the balance between anabolism and catabolism of the nucleus pulposus extracellular matrix. The purpose of this study is to explore the mitigative effect of oxymatrine on extracellular matrix degradation and apoptosis of nucleus pulposus cells after interleukin-1 beta-induced inflammation, and its possible signaling pathway. We examined the gene and protein levels of collagen II, aggrecan, and MMPs (MMP2/3/9/13) and interleukin 6 in nucleus pulposus cells. The results demonstrated that oxymatrine could reduce extracellular matrix degradation and apoptosis of nucleus pulposus cells; interleukin-1 beta prompted the expression of MMPs and interleukin 6 through TLR4/NF-κB axis, while oxymatrine reduced the expression of MMPs and TNF-α induced by interleukin-1 beta. Moreover, TAK 242, as a small molecule inhibitor of TLR4 signaling, was used to detect the effect of oxymatrine on the TLR4/NF-κB signaling. The final experimental results show that oxymatrine could reduce the inflammatory response of nucleus pulposus cells and degradation of nucleus pulposus tissue. Oxymatrine may be a potential medicine to reduce disc inflammation and relieve intervertebral disc degeneration by inhibiting the TLR4/NF-κB signal pathway. Impact statement Currently, drug therapy is a potential treatment for patients with intervertebral disc degeneration. In the present research, oxymatrine intervenes in intervertebral disc degeneration effectively via regulating inflammation in intervertebral disc degeneration rats. Our research highlights the therapeutic potential of oxymatrine in the treatment of intervertebral disc degeneration.

Correlation between serum matrix metalloproteinase and myocardial fibrosis in heart failure patients with reduced ejection fraction: A retrospective analysis.

Objective:A strong correlation exists between myocardial fibrosis and heart failure (HF). Myocardial fibrosis can be detected by cardiac magnetic resonance (CMR), which is a crucial noninvasive imaging method with high specificity and sensitivity. Matrix metalloproteinases (MMPs) are primary proteases responsible for the degradation of extracellular matrix (ECM) components, and they play a vital role in maintaining the balance between anabolism and catabolism of ECM. This study aims to investigate the correlation between cardiac fibrosis detected on CMR and serum MMP-9 levels in patients with HF.Methods:We enrolled 53 patients (age: ≥18 years) with left ventricular ejection fraction (LVEF) ≤40%, who received CMR because of various indications. All patients were divided into two groups-with cardiac fibrosis (n=32) and without cardiac fibrosis (n=21)-detected by CMR with late-Gadolinium. Both groups were then compared according to MMP-9 levels.Results:MMP-9 levels were significantly higher in patients with cardiac fibrosis than those without fibrosis (p<0.01). A correlation was determined between the diffusiveness of fibrosis and serum MMP-9 levels. Besides, a statistically significant correlation was determined between MMP-9 measurements and the number of segments with fibrosis (p<0.05). In the group with cardiac fibrosis, LVEF measurements by CMR were significantly lower (p<0.01), with left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) measurements significantly higher (p<0.01), than the other group. Furthermore, we found a statistically significant correlation between MMP-9 levels and LVEDV and LVESV.Conclusion:MMP-9 levels correlate with cardiac remodeling in patients with HF and could be useful in predicting left ventricular fibrosis. In clinical practice, the use of serum MMP-9 could provide early consideration of therapies for structural and functional pathology of the heart in patients with HF.

CircCDK14 protects against Osteoarthritis by sponging miR-125a-5p and promoting the expression of Smad2

Rationale: Osteoarthritis (OA) is the most common joint disease worldwide. Previous studies have identified the imbalance between extracellular matrix (ECM) catabolism and anabolism in cartilage tissue as the main cause. To date, there is no cure for OA despite a few symptomatic treatments. This study aimed to investigate the role of CircCDK14, a novel circRNA factor, in the progression of OA, and to elucidate its underlying molecular mechanisms.Methods: The function of CircCDK14 in OA, as well as the interaction between CircCDK14 and its downstream target (miR-125a-5p) and mRNA target (Smad2), was evaluated by western blot (WB), immunofluorescence (IF), RNA immunoprecipitation (RIP), quantitative RT-PCR, luciferase assay and fluorescence in situ hybridization (FISH). Rabbit models were introduced to examine the function and mechanism of CircCDK14 in OA in vivo.Results: In our present study, we found that CircCDK14, while being down-regulated in the joint wearing position, regulated metabolism, inhibited apoptosis and promoted proliferation in the cartilage. Mechanically, the protective effect of CircCDK14 was mediated by miR-125a-5p sponging, which downregulated the Smad2 expression and led to the dysfunction of TGF-β signaling pathway. Intra-articular injection of adeno-associated virus-CircCDK14 also alleviated OA in the rabbit model.Conclusion: Our study revealed an important role of CircCDK14/miR-125a-5p/Smad2 axis in OA progression and provided a potential molecular therapeutic strategy for the treatment of OA.

LncRNA HOTAIR upregulates autophagy to promote apoptosis and senescence of nucleus pulposus cells.

Intervertebral disc degeneration (IDD) is a complex and chronic disease that involves disc cell senescence, death, and extracellular matrix (ECM) degradation. HOTAIR, a long non-coding RNA (lncRNA) is reportedly associated with autophagy, whereas autophagy is shown to promote IDD. However, how it affects nucleus pulposus (NP) cells, the primary component of intervertebral discs is still unclear. We hypothesized that HOTAIR promotes NP cell apoptosis and senescence through upregulating autophagy. Thus, silencing HOTAIR should inhibit autophagy and exert a therapeutic effect on IDD. Our in vitro experiments in human NP cells revealed that HOTAIR expression positively correlated with IDD grade, and overexpression enhanced autophagy. Autophagy inhibition via 3-methyladenine reversed HOTAIR stimulatory effects on apoptosis, senescence, and ECM catabolism, while the AMP-activated protein kinase (AMPK) inhibitor Compound C suppressed HOTAIR-induced autophagy through regulating AMPK/mTOR/ULK1 pathways. Our in vivo experiment then illustrated that silencing HOTAIR ameliorates IDD in rats. Collectively, we demonstrated that HOTAIR stimulates autophagy to promote NP cell apoptosis, senescence, and ECM catabolism. Therefore, silencing HOTAIR has the potential to become a treatment option for IDD.

Targeting the IL-1\u03b2/IL-1Ra pathways for the aggregation of human islet amyloid polypeptide in an ex vivo organ culture system of the intervertebral disc

Intervertebral disc degeneration (IDD) is characterized by excessive apoptosis of nucleus pulposus (NP) cells and hyperactive extracellular matrix (ECM) catabolism. Our previous studies revealed the relationship between human islet amyloid polypeptide (hIAPP) and NP cell apoptosis. However, the role of hIAPP aggregates in IDD has not yet been investigated. This study aimed to determine whether the accumulation of hIAPP aggregates promotes IDD progression. The aggregation of hIAPP increased in human NP tissues during IDD. The deposition of hIAPP aggravated the compression-induced IDD that promoted NP cell apoptosis and ECM degradation via IL-1β/IL-1Ra signaling in an ex vivo rat disc model. Moreover, neutralizing IL-1β augmented the protective effects of hIAPP overexpression by decreasing hIAPP aggregation in human NP cells. These results suggest that the aggregation of hIAPP promotes NP cell apoptosis and ECM degradation ex vivo and in vitro by disrupting the balance of IL-1β/IL-1Ra signaling.

Intradiscal injection of sesamin protects from lesion-induced degeneration

ABSTRACT Intervertebral disc degeneration-related diseases are common health problems in the department of orthopedics. However, there is no effective treatment protecting the intervertebral disc from degeneration. Sesamin, a kind of sesame lignans extracted from sesame seed oil, has been proved to inhibit lipopolysaccharide-induced inflammation and extracellular matrix catabolism in rat intervertebral disc in vitro and ex vivo. The present study was designed to investigate the effects of sesamin on lesion-induced intervertebral disc degeneration in vivo. Degeneration of rat tail disc was induced by puncture lesion, followed by intradiscal injection of sesamin. Magnetic resonance imaging (MRI), quantitative real-time polymerase chain reaction, histological analysis, and biochemical analysis were carried out to analyze degeneration progression 2 weeks after surgery. As shown by results, intradiscal injection of sesamin inhibited the MRI signal decrease of nucleus pulposus (NP) in T2-weighted images. The upregulated mRNA expression of MMP-3 and ADAMTS-5 induced by lesion was significantly suppressed by sesamin injection. Sesamin partly protected mRNA expression of Col2a1 and Acan from downregulation. Intradiscal injection of sesamin effectively maintained the normal morphology of disc and inhibited lesion-induced degeneration-related histological changes. Immunohistochemical assay demonstrated that the upregulation of degradative enzymes protein expression and the downregulation of type II collagen expression in NP were suppressed by sesamin. According to biochemical analysis, sesamin significantly inhibited the lesion-induced decrease of proteoglycan content in NP. The present study proved the protective effects of sesamin on lesion-induced intervertebral disc degeneration at an early stage.