Hypertrophic scar (HS) is a common fibroproliferative disorders with no fully effective treatments. The conversion of fibroblasts to myofibroblasts is known to play a critical role in HS formation, making it essential to identify molecules that promote myofibroblast dedifferentiation and to elucidate their underlying mechanisms. In this study, we used comparative transcriptomics and single-cell sequencing to identify key molecules and pathways that mediate fibrosis and myofibroblast transdifferentiation. Epidermal stem cell-derived extracellular vesicles (EpiSC-EVs) were isolated via ultracentrifugation and filtration, followed by miRNA sequencing to identify miRNAs targeting key molecules. After in vitro and in vivo treatment with EpiSC-EVs, we assessed antifibrotic effects through scratch assays, collagen contraction assays, Western blotting, and immunofluorescence. Transcriptomic sequencing and rescue experiments were used to investigate the molecular mechanism by which miR-203a-3p in EpiSC-EVs induces myofibroblast dedifferentiation. Our results indicate that PIK3CA is overexpressed in HS tissues and positively correlates with fibrosis. EpiSC-EVs were absorbed by scar-derived fibroblasts, promoting dedifferentiation from myofibroblasts to quiescent fibroblasts. Mechanistically, miR-203a-3p in EpiSC-EVs plays an essential role in inhibiting PIK3CA expression and PI3K/AKT/mTOR pathway hyperactivation, thereby reducing scar formation. In vivo studies confirmed that EpiSC-EVs attenuate excessive scarring through the miR-203a-3p/PIK3CA axis, suggesting EpiSC-EVs as a promising therapeutic approach for HS.
Osteoarthritis (OA) is a chronic articular disease characterized by cartilage degradation, subchondral bone remodeling and osteophyte formation. Src homology 2 domain-containing protein tyrosine phosphatase (SHP2) has not been fully investigated in the pathogenesis of OA. In this study, we found that SHP2 expression was significantly increased after interleukin-1β (IL-1β) treatment in primary mouse chondrocytes. Inhibition of SHP2 using siRNA reduced MMP3, MMP13 levels, but increased AGGRECAN, COL2A1, SOX9 expression in vitro . On the contrary, overexpression of SHP2 exerted the opposite results and promoted cartilage degradation. Mechanistically, SHP2 activated Wnt/β-catenin signaling possibly through directly binding to β-catenin. SHP2 also induced inflammation through activating Mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) pathways. Our in vivo studies showed that SHP2 knockdown effectively delayed cartilage destruction and reduced osteophyte formation in the mouse model of OA induced by destabilization of the medial meniscus (DMM). Altogether, our study identifies that SHP2 is a novel and potential therapeutic target of OA.
Osteoporosis is a common chronic metabolic bone disease characterized by reduced trabecular bone and increased bone fragility. Monoacylglycerol lipase (MAGL) is a lipolytic enzyme to catalyze the hydrolysis of monoglycerides and specifically degrades the 2-arachidonoyl glycerol (2-AG). Previous studies have identified that 2-AG is the mainly source for arachidonic acid and the most abundant endogenous agonist of cannabinoid receptors. Considering the close relationship between inflammatory mediators/cannabinoid receptors and bone metabolism, we speculated that MAGL may play a role in the osteoclast differentiation. In the present study, we found that MAGL protein expression increased during osteoclast differentiation. MAGL knockdown by adenovirus-mediated shRNA in bone marrow-derived macrophages demonstrated the suppressive effects of MAGL on osteoclast formation and bone resorption. In addition, pharmacological inhibition of MAGL by JZL184 suppressed osteoclast differentiation, bone resorption, and osteoclast-specific gene expression. Activation of the Mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) pathways was inhibited by JZL184 and deletion of MAGL. Our in vivo study indicated that JZL184 ameliorated bone loss in an ovariectomized mouse model. Furthermore, overexpressing H1 calponin partially alleviated the inhibition caused by JZL184 or MAGL deletion on osteoclastogenesis. Therefore, we conclude that targeting MAGL may be a novel therapeutic strategy for osteoporosis.
Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial hyperplasia, pannus formation, and cartilage and bone destruction. Nuclear receptor subfamily 1 group D member 1 (NR1D1) functions as a transcriptional repressor and plays a vital role in inflammatory reactions. However, whether NR1D1 is involved in synovial inflammation and joint destruction during the pathogenesis of RA is unknown. In this study, we found that NR1D1 expression was increased in synovial tissues from patients with RA and decreased in RA Fibroblast-like synoviocytes (FLSs) stimulated with IL-1β in vitro. We showed that NR1D1 activation decreased the expression of proinflammatory cytokines and matrix metalloproteinases (MMPs), while NR1D1 silencing exerted the opposite effect. Furthermore, NR1D1 activation reduced reactive oxygen species (ROS) generation and increased the production of nuclear transcription factor E2-related factor 2 (Nrf2)-associated enzymes. Mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) pathways were blocked by the NR1D1 agonist SR9009 but activated by NR1D1 silencing. NR1D1 activation also inhibited M1 macrophage polarization and suppressed osteoclastogenesis and osteoclast-related genes expression. Treatment with NR1D1 agonist SR9009 in collagen-induced arthritis (CIA) mouse significantly suppressed the hyperplasia of synovial, infiltration of inflammatory cell and destruction of cartilage and bone. Our findings demonstrate an important role for NR1D1 in RA and suggest its therapeutic potential.
Abstract Destructive bone diseases caused by osteolysis are increasing in incidence. They are characterized by an excessive imbalance of osteoclast formation and activation. During osteolysis, the activation of nuclear factor‐κB (NF‐κB) and mitogen‐activated protein kinase (MAPK) signaling pathways are triggered by receptor activator of NF‐κB ligand (RANKL), inflammatory factors, and oxidative stress. Previous studies have indicated that the common flavanone glycoside compound hesperetin exhibits anti‐inflammatory and antioxidant activity by inhibition of NF‐κB and MAPK signaling pathways. However, the direct relationship between hesperetin and osteolysis remain unclear. In the present study, we investigated the effects of hesperetin on lipopolysaccharide (LPS)‐induced osteoporosis and elucidated the related mechanisms. Hesperetin effectively suppressed RANKL‐induced osteoclastogenesis, osteoclastic bone resorption, and F‐actin ring formation in a dose‐dependent manner. It also significantly suppressed the expression of osteoclast‐specific markers including tartrate‐resistant acid phosphatase, matrix metalloproteinase‐9, cathepsin K, c‐Fos, and nuclear factor of activated T‐cells cytoplasmic 1. Furthermore, it inhibited osteoclastogenesis by inhibiting activation of NF‐κB and MAPK signaling, scavenging reactive oxygen species, and activating the nuclear factor E2 p45‐related factor 2/heme oxygenase 1 (Nrf2/HO‐1) signaling pathway. Consistent with in vitro results, hesperetin effectively ameliorated LPS‐induced bone loss, reduced osteoclast numbers, and decreased the RANKL/OPG ratio in vivo. As such, our results suggest that hesperetin may be a great candidate for developing a novel drug for destructive bone diseases such as periodontal disease, tumor bone metastasis, rheumatoid arthritis, and osteoporosis.
Osteoporosis is a result of impaired bone formation and/or excessive bone resorption. Osteoclasts are the only cells in the body that have a bone resorption function. Inhibiting osteoclast activity and differentiation is a way to treat osteoporosis. The current pharmacological treatment for osteoporosis has many shortcomings, and more effective treatments are needed. Vinpocetine (Vinp), a derivative of the alkaloid vincamine, has been used to treat cerebrovascular disorders and cognitive impairment for a long time. Vinp inhibits mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB)-dependent inflammatory responses and oxidative damage in which osteoclasts are often involved. However, the effects of Vinp on the regulation of osteoclast activity remain unknown. In this study, we found that Vinp significantly inhibited receptor activator of NF-κB ligand (RANKL)-induced osteoclast and F-actin formation and decreased osteoclastic bone resorption in vitro. Vinp also suppressed the expression of osteoclast-specific genes, including NFATc1, c-Fos, tartrate-resistant acid phosphatase (TRAP), matrix metalloproteinase-9 (MMP-9), and cathepsin K (CTSK) at both the mRNA and protein levels. Vinp reduced activation of NF-κB, MAPK, and AKT signaling during osteoclastogenesis and prevented the production of reactive oxygen species with increased nuclear factor erythroid 2-related factor 2, heme oxygenase 1, and NAD(P)H:quinone acceptor oxidoreductase 1 expression. Animal experiments consistently demonstrated that Vinp treatment significantly attenuated ovariectomy-induced bone loss with a decrease in the osteoclast number and decreases in serum levels of RANKL, TRAP, interleukin-1β, and tumor necrosis factor-alpha, as well as increased serum levels of osteoprotegerin. Taken together, our findings reveal that Vinp may be a potential pharmacological choice for preventing and treating osteoporosis.
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