DUSP5 suppresses interleukin-1β-induced chondrocyte inflammation and ameliorates osteoarthritis in rats

Impact of knockout of dual-specificity protein phosphatase 5 on structural and mechanical properties of rat middle cerebral arteries: implications for vascular aging

Vascular aging influences hemodynamics, elevating risks for vascular diseases and dementia. We recently demonstrated that knockout (KO) of Dusp5 enhances cerebral and renal hemodynamics and cognitive function. This improvement correlates with elevated pPKC and pERK1/2 levels in the brain and kidneys. Additionally, we observed that Dusp5 KO modulates the passive mechanical properties of cerebral and renal arterioles, associated with increased myogenic tone at low pressure, enhanced distensibility, greater compliance, and reduced stiffness. The present study evaluates the structural and mechanical properties of the middle cerebral artery (MCA) in Dusp5 KO rats. We found that vascular smooth muscle cell layers and the collagen content in the MCA wall are comparable between Dusp5 KO and control rats. The internal elastic lamina in the MCA of Dusp5 KO rats exhibits increased thickness, higher autofluorescence intensity, smaller fenestrae areas, and fewer fenestrations. Despite an enhanced myogenic response and tone of the MCA in Dusp5 KO rats, other passive mechanical properties, such as wall thickness, cross-sectional area, wall-to-lumen ratio, distensibility, incremental elasticity, circumferential wall stress, and elastic modulus, do not significantly differ between strains. These findings suggest that while Dusp5 KO has a limited impact on altering the structural and mechanical properties of MCA, its primary role in ameliorating hemodynamics and cognitive functions is likely attributable to its enzymatic activity on cerebral arterioles. Further research is needed to elucidate the specific enzymatic mechanisms and explore potential clinical applications in the context of vascular aging.

Oxymatrine protects articular chondrocytes from IL-1β-induced damage through autophagy activation via AKT/mTOR signaling pathway inhibition

BACKGROUND

Osteoarthritis (OA) is a common degenerative joint disease characterized by persistent articular cartilage degeneration and synovitis. Oxymatrine (OMT) is a quinzolazine alkaloid extracted from the traditional Chinese medicine, matrine, and possesses anti-inflammatory properties that may help regulate the pathogenesis of OA; however, its mechanism has not been elucidated. This study aimed to investigate the effects of OMT on interleukin-1β (IL-1β)-induced damage and the potential mechanisms of action.

METHODS

Chondrocytes were isolated from Sprague-Dawley rats. Toluidine blue and Collagen II immunofluorescence staining were used to determine the purity of the chondrocytes. Thereafter, the chondrocytes were subjected to IL-1β stimulation, both in the presence and absence of OMT, or the autophagy inhibitor 3-methyladenine (3-MA). Cell viability was assessed using the MTT assay and SYTOX Green staining. Additionally, flow cytometry was used to determine cell apoptosis rate and reactive oxygen species (ROS) levels. The protein levels of AKT, mTOR, LC3, P62, matrix metalloproteinase-13, and collagen II were quantitatively analyzed using western blotting. Immunofluorescence was used to assess LC3 expression.

RESULTS

OMT alleviated IL-1β-induced damage in chondrocytes, by increasing the survival rate, reducing the apoptosis rates of chondrocytes, and preventing the degradation of the cartilage matrix. In addition, OMT decreased the ROS levels and inhibited the AKT/mTOR signaling pathway while promoting autophagy in IL-1β treated chondrocytes. However, the effectiveness of OMT in improving chondrocyte viability under IL-1β treatment was limited when autophagy was inhibited by 3-MA.

CONCLUSIONS

OMT decreases oxidative stress and inhibits the AKT/mTOR signaling pathway to enhance autophagy, thus inhibiting IL-1β-induced damage. Therefore, OMT may be a novel and effective therapeutic agent for the clinical treatment of OA.

Ataluren prevented bone loss induced by ovariectomy and aging in mice through the BMP-SMAD signaling pathway

Both estrogen deficiency and aging may lead to osteoporosis. Developing novel drugs for treating osteoporosis is a popular research direction. We screened several potential therapeutic agents through a new deep learning-based efficacy prediction system (DLEPS) using transcriptional profiles for osteoporosis. DLEPS screening led to a potential novel drug examinee, ataluren, for treating osteoporosis. Ataluren significantly reversed bone loss in ovariectomized mice. Next, ataluren significantly increased human bone marrow-derived mesenchymal stem cell (hBMMSC) osteogenic differentiation without cytotoxicity, indicated by the high expression index of osteogenic differentiation genes (OCN , BGLAP, ALP, COL1A, BMP2, RUNX2). Mechanistically, ataluren exerted its function through the BMP-SMAD pathway. Furthermore, it activated SMAD phosphorylation but osteogenic differentiation was attenuated by BMP2-SMAD inhibitors or small interfering RNA of BMP2. Finally, ataluren significantly reversed bone loss in aged mice. In summary, our findings suggest that the DLEPS-screened ataluren may be a therapeutic agent against osteoporosis by aiding hBMMSC osteogenic differentiation.

The Role of Epinephelus coioides DUSP5 in Regulating Singapore Grouper Iridovirus Infection

The dual-specificity phosphatase (DUSP) family plays an important role in response to adverse external factors. In this study, the DUSP5 from Epinephelus coioides, an important marine fish in Southeast Asia and China, was isolated and characterized. As expected, E. coioides DUSP5 contained four conserved domains: a rhodanese homology domain (RHOD); a dual-specificity phosphatase catalytic domain (DSPc); and two regions of low compositional complexity, indicating that E. coioides DUSP5 belongs to the DUSP family. E. coioides DUSP5 mRNA could be detected in all of the examined tissues, and was mainly distributed in the nucleus. Infection with Singapore grouper iridovirus (SGIV), one of the most important pathogens of marine fish, could inhibit the expression of E. coioides DUSP5. The overexpression of DUSP5 could significantly downregulate the expression of the key SGIV genes (MCP, ICP18, VP19, and LITAF), viral titers, the activity of NF-κB and AP-I, and the expression of pro-inflammatory factors (IL-6, IL-8, and TNF-α) of E. coioides, but could upregulate the expressions of caspase3 and p53, as well as SGIV-induced apoptosis. The results demonstrate that E. coioides DUSP5 could inhibit SGIV infection by regulating E. coioides immune-related factors, indicating that DUSP5 might be involved in viral infection.

Radical-Scavenging and Subchondral Bone-Regenerating Nanomedicine for Osteoarthritis Treatment

Osteoarthritis (OA) is characterized by cartilage degradation and subchondral bone remodeling. However, most available studies focus on either cartilage degradation or subchondral bone lesion, alone, and rarely pay attention to the synergy of these two pathological changes. Herein, a dual-functional medication is developed to simultaneously protect cartilage and achieve subchondral bone repair. Black phosphorus nanosheets (BPNSs), with a strong reactive oxygen species (ROS)-scavenging capability and high biocompatibility, also present a notable promoting effect in osteogenesis. BPNSs efficiently eliminate the intracellular ROS and, thus, protect the inherent homeostasis between cartilage matrix anabolism and catabolism. RNA sequencing results of BPNSs-treated OA chondrocytes further reveal the restoration of chondrocyte function, activation of antioxidant enzymes, and regulation of inflammation. Additional in vivo assessments solidly confirm that BPNSs inhibit cartilage degradation and prevent OA progression. Meanwhile, histological evaluation and microcomputed tomography (micro-CT) scanning analysis verify the satisfying disease-modifying effects of BPNSs on OA. Additionally, the excellent biocompatibility of BPNSs enables them as a competitive candidate for OA treatment. This distinct disease-modifying treatment of OA on the basis of BPNSs provides an insight and paradigm on the dual-functional treatment strategy focusing on both cartilage degradation and subchondral bone lesion in OA and explores a broader biomedical application of BPNS nanomedicine in orthopedics.

MiR-216a-3p inhibits the proliferation and invasion of fibroblast-like synoviocytes by targeting dual-specificity phosphatase 5

Dual-specificity phosphatase 5 (DUSP5) is a novel anti-inflammatory modulator in many inflammatory diseases. However, the role of DUSP5 in fibroblast-like synoviocytes (FLS) of rheumatoid arthritis (RA) remains unknown. In this study, we aimed to explore the biological function and regulation of DUSP5 in FLS. We found that lower DUSP5 expression level was detected in collagen-induced arthritis (CIA) and synoviocyte MH7A. Overexpression of DUSP5 markedly decreased the proliferation, migration, and invasion of MH7A, which correlated with suppressing the phosphorylation of extracellular signal-regulated kinase (ERK). Moreover, DUSP5 was identified as a novel target gene of miR-216a-3p, which was upregulated in FLS. Therefore, DUSP5 expression was negatively regulated by miR-216a-3p, and the effect of DUSP5 overexpression on FLS was reversed by miR-216a-3p mimics. Overall, our study demonstrates that DUSP5 is a miR-216a-3p target gene and its anti-inflammatory function in FLS via inactivation of ERK. These results revealed that the miR-216a-3p/DUSP5 pathway may play a crucial role in the malignant behavior of FLS, which may serve as a new target for the treatment of RA.

Circ_0001721 knockdown relieves IL-1β-induced chondrocyte injury via regulating miR-373-3p/CXCR4 in osteoarthritis

BACKGROUND

Circular RNA (circRNA) plays an important role in osteoarthritis (OA) progression. Circ_0001721 has been noted to be significantly overexpressed in OA patients, but its function in OA progression remain unclear. The purpose of this study was to investigate the role and mechanism of circ_0001721 in OA progression.

METHODS

Interleukin-1β (IL-1β)-induced chondrocytes were used to mimic OA cell model in vitro. The expression of circ_0001721, microRNA (miR)-373-3p and CXC chemokine receptor 4 (CXCR4) was examined by quantitative real-time PCR. The concentrations of inflammatory factors were assessed by ELISA assay. Cell proliferation and apoptosis were determined by MTT assay, EdU assay and flow cytometry. Protein levels were detected by western blot analysis. The interaction between miR-373-3p and circ_0001721 or CXCR4 was confirmed by dual-luciferase reporter assay, RIP assay and RNA pull-down assay.

RESULTS

Our results showed that circ_0001721 was highly expressed in OA patients and IL-1β-induced chondrocytes. IL-1β treatment could suppress the proliferation, while promote the apoptosis, extracellular matrix (ECM) degradation and inflammation of chondrocytes. Knockdown of circ_0001721 alleviated IL-1β-induced chondrocyte injury. MiR-373-3p could be sponged by circ_0001721, and its inhibitor reversed the regulation of circ_0001721 knockdown on IL-1β-induced chondrocyte injury. CXCR4 was a target of miR-373-3p, and circ_0001721 could sponge miR-373-3p to regulate CXCR4. Furthermore, miR-373-3p overexpression inhibited IL-1β-induced chondrocyte injury, and these effects could be overturned by CXCR4 upregulation.

CONCLUSION

Our data confirmed that circ_0001721 knockdown alleviated IL-1β-induced chondrocyte injury by miR-373-3p/CXCR4 axis, which suggested that circ_0001721 might be a potential therapeutic target for OA.

miR-203 suppresses pancreatic cancer cell proliferation and migration by modulating DUSP5 expression

BACKGROUND

Pancreatic cancer (PC) is an insidious cancer that is commonly diagnosed in advanced stages. Therefore, it is necessary to understand PC-related mechanisms in order to discover new and reliable diagnostic biomarkers. It is known that miRNAs play a crucial role in carcinogenesis by targeting mRNAs. In this study we aimed to explore interaction between downregulated miR-203 and its upregulated target DUSP5 in PC.

METHODS

Using bioinformatics approaches we identified the DUSP5 as a direct target gene of miR-203 and detected potential binding sites between miR-203 and DUSP5. Additionally, we evaluated subcellular location, expression level and prognostic value of DUSP5 in PC through using various bioinformatics tools. To investigate the relationship between miR-203 and DUSP5, we increased the expression levels of miR-203 by transfecting miR-203 mimics into the pancreatic cancer cell line, PANC-1. Finally, MTT, wound healing, and colony formation assays were performed to determine effect of overexpressed miR-203 on proliferation and migration of PANC-1 cells.

RESULTS

We found that expression level of DUSP5 in pancreas tissue was one of the lowest tissue expression among all normal human tissue types. In addition, DUSP5 expression was upregulated both PC tissues and cell line and associated with poor overall survival in PC. Overexpression of miR-203 significantly downregulated expression level of DUSP5 and remarkably suppressed proliferation, migration and colony formation ability of PANC-1 cells.

CONCLUSIONS

These findings suggest that miR-203 restrains proliferation and migration of PC cells by regulating oncogenic activity of DUSP5 in PC, thereby could be novel candidate biomarkers for PC diagnosis and treatment.

Targeting protein phosphatases for the treatment of inflammation-related diseases: From signaling to therapy

Inflammation is the common pathological basis of autoimmune diseases, metabolic diseases, malignant tumors, and other major chronic diseases. Inflammation plays an important role in tissue homeostasis. On one hand, inflammation can sense changes in the tissue environment, induce imbalance of tissue homeostasis, and cause tissue damage. On the other hand, inflammation can also initiate tissue damage repair and maintain normal tissue function by resolving injury and restoring homeostasis. These opposing functions emphasize the significance of accurate regulation of inflammatory homeostasis to ameliorate inflammation-related diseases. Potential mechanisms involve protein phosphorylation modifications by kinases and phosphatases, which have a crucial role in inflammatory homeostasis. The mechanisms by which many kinases resolve inflammation have been well reviewed, whereas a systematic summary of the functions of protein phosphatases in regulating inflammatory homeostasis is lacking. The molecular knowledge of protein phosphatases, and especially the unique biochemical traits of each family member, will be of critical importance for developing drugs that target phosphatases. Here, we provide a comprehensive summary of the structure, the "double-edged sword" function, and the extensive signaling pathways of all protein phosphatases in inflammation-related diseases, as well as their potential inhibitors or activators that can be used in therapeutic interventions in preclinical or clinical trials. We provide an integrated perspective on the current understanding of all the protein phosphatases associated with inflammation-related diseases, with the aim of facilitating the development of drugs that target protein phosphatases for the treatment of inflammation-related diseases.

Nootkatone protects cartilage against degeneration in mice by inhibiting NF-κB signaling pathway

Osteoarthritis is a common chronic disease associated with chondrocyte inflammation and cartilage matrix hydrolyzation. Studies report that IL-1β plays a critical role in osteoarthritis. Anti-inflammatory effect of nootkatone has been explored in acute and chronic inflammatory disease, thus the current study sought to explore its therapeutic effect in osteoarthritis. Notably, the effect of nootkatone in osteoarthritis has not been elucidated. Therefore, murine primary chondrocytes were extracted and ACLT induced OA mouse model was established in the current study to explore the therapeutic effect of nootkatone in OA both in vitro and in vivo. The findings showed that nootkatone inhibited inflammatory response and protected cartilage balance in murine primary chondrocyte. Further analysis showed that nootkatone suppressed inflammation and protected cartilage against degeneration induced by ACLT surgery in mice. The cellular mechanism of the protective effect of nootkatone in osteoarthritis and associated signaling pathway was identified as the NF-κB signaling pathway. In summary, the findings of the current study indicated that nootkatone is a potential therapeutic agent for OA.

Rutin inhibited the advanced glycation end products-stimulated inflammatory response and extra-cellular matrix degeneration via targeting TRAF-6 and BCL-2 proteins in mouse model of osteoarthritis

BACKGROUND

Osteoarthritis (OA) is degenerative joint disorder mainly characterized by long-term pain with limited activity of joints, the disease has no effective preventative therapy. Rutin (RUT) is a flavonoid compound, present naturally. The flavonoid shows range of biological activities such as anti-inflammatory and anti-cancer effect. We screened RUT for its activity against osteoarthritis with in vivo and in vitro models of osteoarthritis.

METHODS

Animal model of OA was developed using C57BL/6 mice by surgical destabilization of medial meniscus. For in vitro studies the human articular cartilage tissues were used which were collected from osteoarthritis patients and were processed to isolate chondrocytes. The chondrocytes were submitted to advanced glycation end products (AGEs) for inducing osteoarthritis in vitro. Cell viability was done by CCK-8 assay, ELISA analysis for MMP13, collage II, PGE2, IL-6, TNF-α, ADAMTS-5 and MMP-13. Western blot analysis was done for expression of proteins and in silico analysis was done by docking studies.

RESULTS

Pretreatment of RT showed no cytotoxic effect and also ameliorated the AGE mediated inflammatory reaction on human chondrocytes in vitro. Treatment of RT inhibited the levels of COX-2 and iNOS in AGE exposed chondrocytes. RT decreased the AGE mediated up-regulation of IL-6, NO, TNF-α and PGE-2 in a dose dependent manner. Pretreatment of RT decreased the extracellular matrix degradation, inhibited expression of TRAF-6 and BCL-2 the NF-κB/MAPK pathway proteins. The treatment of RT in mice prevented the calcification of cartilage tissues, loss of proteoglycans and also halted the narrowing of joint space is mice subjected to osteoarthritis. The in-silico analysis suggested potential binding affinity of RT with TRAF-6 and BCL-2.

CONCLUSION

In brief RT inhibited AGE-induced inflammatory reaction and also degradation of ECM via targeting the NF-κB/MAPK pathway proteins BCL-2 and TRAF-6. RT can be a potential molecule in treating OA.

Silencing of AFAP1-AS1 lncRNA impairs cell proliferation and migration by epigenetically promoting DUSP5 expression in pre-eclampsia

As a unique and common obstetric complication of pregnant women, pre-eclampsia (PE) has been the first leading cause of maternal and perinatal morbidity and mortality in the world. Mounting studies have demonstrated that an abnormality of long noncoding RNA (lncRNA) expression was related to the pathological process of PE. Here, we showed that lncRNA AFAP1-AS1 was markedly downregulated in pre-eclamptic placentas. We further investigated the mechanism underlying the regulatory role of AFAP1-AS1 in PE using human trophoblast cells. In vitro functional assays revealed that AFAP1-AS1 knockdown inhibited trophoblast proliferation, migration, and invasion. Moreover, AFAP1-AS1 interacts with EZH2 and inhibits DUSP5 expression through modulating H3K27m3 in the DUSP5 promoter of trophoblast cells, thus being involved in PE pathogenesis. Overall, these findings suggest that AFAP1-AS1 could potentially become a prognostic biomarker as well as a new therapeutic target for PE.

DUSP5 promotes osteogenic differentiation through SCP1/2-dependent phosphorylation of SMAD1

Dual‐specificity phosphatases (DUSPs) are defined by their capability to dephosphorylate both phosphoserine/phosphothreonine (pSer/pThr) and phosphotyrosine (pTyr). DUSP5, a member of DUSPs superfamily, is located in the nucleus and plays crucially regulatory roles in the signaling pathway transduction. In our present study, we discover that DUSP5 significantly promotes osteogenic differentiation of mesenchymal stromal cells (MSCs) by activating SMAD1 signaling pathway. Mechanistically, DUSP5 physically interacts with the phosphatase domain of small C‐terminal phosphatase 1/2 (SCP1/2, SMAD1 phosphatases) by the linker region. In addition, we further confirm that DUSP5 activates SMAD1 signaling through a SCP1/2‐dependent manner. Specifically, DUSP5 attenuates the SCP1/2‐SMAD1 interaction by competitively binding to SCP1/2, which is responsible for the SMAD1 dephosphorylation, and thus results in the activation of SMAD1 signaling. Importantly, DUSP5 expression in mouse bone marrow MSCs is significantly reduced in ovariectomized (OVX) mice in which osteogenesis is highly passive, and overexpression of Dusp5 via tail vein injection reverses the bone loss of OVX mice efficiently. Collectively, this work demonstrates that the linker region of DUSP5 maybe a novel chemically modifiable target for controlling MSCs fate choices and for osteoporosis treatment.

Obeticholic Acid Derivative, T-2054 Suppresses Osteoarthritis via Inhibiting NF-κB-Signaling Pathway

Osteoarthritis (OA), a degenerative joint disorder, has been reported as the most common cause of disability worldwide. The production of inflammatory cytokines is the main factor in OA. Previous studies have been reported that obeticholic acid (OCA) and OCA derivatives inhibited the release of proinflammatory cytokines in acute liver failure, but they have not been studied in the progression of OA. In our study, we screened our small synthetic library of OCA derivatives and found T-2054 had anti-inflammatory properties. Meanwhile, the proliferation of RAW 264.7 cells and ATDC5 cells were not affected by T-2054. T-2054 treatment significantly relieved the release of NO, as well as mRNA and protein expression levels of inflammatory cytokines (IL-6, IL-8 and TNF-α) in LPS-induced RAW 264.7 cells. Moreover, T-2054 promoted extracellular matrix (ECM) synthesis in TNF-α-treated ATDC5 chondrocytes. Moreover, T-2054 could relieve the infiltration of inflammatory cells and degeneration of the cartilage matrix and decrease the levels of serum IL-6, IL-8 and TNF-α in DMM-induced C57BL/6 mice models. At the same time, T-2054 showed no obvious toxicity to mice. Mechanistically, T-2054 decreased the extent of p-p65 expression in LPS-induced RAW 264.7 cells and TNF-α-treated ATDC5 chondrocytes. In summary, we showed for the first time that T-2054 effectively reduced the release of inflammatory mediators, as well as promoted extracellular matrix (ECM) synthesis via the NF-κB-signaling pathway. Our findings support the potential use of T-2054 as an effective therapeutic agent for the treatment of OA.