Leptin, an adipocyte-derived cytokine associated with bone metabolism, is believed to play a critical role in the pathogenesis of heterotopic ossification (HO). The effect and underlying action mechanism of leptin were investigated on osteogenic differentiation of tendon-derived stem cells (TDSCs) in vitro and the HO formation in rat tendons. Isolated rat TDSCs were treated with various concentrations of leptin in the presence or absence of mTORC1 signaling specific inhibitor rapamycin in vitro. A rat model with Achilles tenotomy was employed to evaluate the effect of leptin on HO formation together with or without rapamycin treatment. In vitro studies with TDSCs showed that leptin increased the expression of osteogenic biomarkers (alkaline phosphatase, runt-related transcription factor 2, osterix, osteocalcin) and enhanced mineralization of TDSCs via activating the mTORC1 signal pathway (as indicated by phosphorylation of p70 ribosomal S6 kinase 1 and p70 ribosomal S6). However, mTORC1 signaling blockade with rapamycin treatment suppressed leptin-induced osteogenic differentiation and mineralization. In vivo studies showed that leptin promoted HO formation in the Achilles tendon after tenotomy, and rapamycin treatment blocked leptin-induced HO formation. In conclusion, leptin can promote TDSC osteogenic differentiation and heterotopic bone formation via mTORC1 signaling in both vitro and vivo model, which provides a new potential therapeutic target for HO prevention.
This paper aims to probe into the effect of sweroside (SOS) in osteoporosis (OP) and explains mechanisms of its molecular. Applying the ovariectomized (OVX) mouse model investigates the preventive effect of SOS against postmenopausal OP after 3 months of SOS treatment (120 mg/kg/day). Using hematoxylin and eosin (HE) staining and micro computed tomography (CT) observed the morphology of OP in each group. Immunohistochemical staining (IHC) was used to examine osteoblast markers. Experiments in vitro, bone marrow mesenchymal stem cells (BMSCs) from C57/BL6 mice were treated with SOS for 14 days. The staining of alizarin red and alkaline phosphatase activity were measured, and the presentation of osteoblast markers was detected by quantitative reverse transcription PCR. BMSCs were also treated with 1 μg/mL SOS with or without rapamycin, the expression of protein S6 (PS6), P‐mTOR, runt‐related transcription factor 2 (RUNX2), OSX, and osteocalcin (OCN) was detected by Western blotting. Experiments in vivo, HE results show that SOS can alleviate OP, CT results show that there are lower trabecular thickness, bone mineral density, and trabecular number in control OVX mice than those in the OVX + SOS group. IHC results showed that SOS can promote the expression of osteogenic markers and immunofluorescent results show that SOS can promote mTORC1 signal activation. Experiments in vitro revealed that SOS stimulated the activation of the mTORC1 signaling pathway and upregulated RUNX2, OSX, and OCN, rapamycin can reverse it. Our findings demonstrated that differentiated BMSCs into osteoblasts can be promoted by SOS via upregulating the expression of P‐mTOR, PS6, RUNX2, OSX, and OCN. SOS effectively prevented OP by hyperactivation of the mTORC1/PS6 signaling pathway.
Excessive mechanical loading is a major factor affecting heterotopic ossification (HO), which is a major pathological alteration in calcific tendinopathy. However, physical therapies with mechanical loading as the functional element have exhibited promising results in the treatment of calcific tendinopathy. The dual effects that mechanical loading may have on the pathogenesis and rehabilitation of calcified tendinopathy remain unclear. The present study was designed to investigate the effects of mechanical loading on HO in calcific tendinopathy. In the present study, a tendon cell in vitro stretch model and an Achilles tenotomy rat model were used to simulate different elongation mechanical loading scenarios in order to investigate the effects of mechanical loading on HO of the tendon. In addition, rapamycin, a selective mammalian target of rapamycin complex-1 (mTORC1) signaling pathway inhibitor, was employed to determine whether mechanical loading modulates heterotopic ossification in calcific tendinopathy through the mTORC1 signaling pathway. The data indicate that mechanical loading modulated HO of the tendon through the mTORC1 signaling pathway, and that low elongation mechanical loading attenuated HO, while high elongation mechanical loading accelerated HO in vivo. This study may improve the understanding of the effect of physical therapies used to treat calcific tendinopathy, so as to guide clinical treatment more effectively. Furthermore, rapamycin may be a potential drug for the treatment of calcific tendinopathy.
Background Tendon-bone healing is a reconstructive procedure which requires a tendon graft healing to a bone tunnel or to the surface of bone after the junction injury between tendon, ligament, and bone. The surgical reattachment of tendon to bone often fails due to regeneration failure of the specialized tendon-bone junction. Materials and Methods An extra-articular tendon-bone healing rat model was established to discuss the effect of the baicalein 10 mg/(kg·d) in accelerating tendon-bone healing progress. Also, tendon-derived stem cells (TDSCs) were treated with various concentrations of baicalein or dickkopf-1 (DKK-1) to stimulate differentiation for 14 days. Results In vivo, tendon-bone healing strength of experiment group was obviously stronger than the control group in 3 weeks as well as in 6 weeks. And there were more mature fibroblasts, more Sharpey fibers, and larger new bone formation area treated intragastrically with baicalein compared with rats that were treated with vehicle for 3 weeks and 6 weeks. In vitro, after induction for 14 days, the expressions of osteoblast differentiation markers, that is, alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), osteocalcin (OCN), osterix (OSX), and collagen I, were upregulated and Wnt/β-catenin signaling pathway was enhanced in TDSCs. The effect of DKK-1 significantly reduced the effect of baicalein on the osteogenic differentiation. Conclusion These data suggest that baicalein may stimulate TDSCs osteogenic differentiation via activation of Wnt/β-catenin signaling pathway to accelerate tendon-bone healing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.