AbstractDespite decades of progress, developing minimally invasive bone‐specific drug delivery systems (DDS) to improve fracture healing remains a significant clinical challenge. To address this critical therapeutic need, nanoparticle (NP) DDS comprised of poly(styrene‐alt‐maleic anhydride)‐b‐poly(styrene) (PSMA‐b‐PS) functionalized with a peptide that targets tartrate‐resistant acid phosphatase (TRAP) and achieves preferential fracture accumulation has been developed. The delivery of AR28, a glycogen synthase kinase‐3 beta (GSK3β) inhibitor, via the TRAP binding peptide‐NP (TBP‐NP) expedites fracture healing. Interestingly, however, NPs are predominantly taken up by fracture‐associated macrophages rather than cells typically associated with fracture healing. Therefore, the underlying mechanism of healing via TBP‐NP is comprehensively investigated herein. TBP‐NPAR28 promotes M2 macrophage polarization and enhances osteogenesis in preosteoblast‐macrophage co‐cultures in vitro. Longitudinal analysis of TBP‐NPAR28‐mediated fracture healing reveals distinct spatial distributions of M2 macrophages, an increased M2/M1 ratio, and upregulation of anti‐inflammatory and downregulated pro‐inflammatory genes compared to controls. This work demonstrates the underlying therapeutic mechanism of bone‐targeted NP DDS, which leverages macrophages as druggable targets and modulates M2 macrophage polarization to enhance fracture healing, highlighting the therapeutic benefit of this approach for fractures and bone‐associated diseases.

2018-03-01·Journal of Cellular Physiology2区 · 生物学

GSK‐3β inhibition suppresses instability‐induced osteolysis by a dual action on osteoblast and osteoclast differentiation

2区 · 生物学

Article

作者: Fahlgren, Anna ; Bostrom, Mathias P. ; Ross, F. Patrick ; Madsen, Rune V. ; Escott, K. Jane ; Amirhosseini, Mehdi

Currently, there are no medications available to treat aseptic loosening of orthopedic implants. Using osteoprotegerin fusion protein (OPG‐Fc), we previously blocked instability‐induced osteoclast differentiation and peri‐prosthetic osteolysis. Wnt/β‐catenin signaling, which regulates OPG secretion from osteoblasts, also modulates the bone tissue response to mechanical loading. We hypothesized that activating Wnt/β‐catenin signaling by inhibiting glycogen synthase kinase‐3β (GSK‐3β) would reduce instability‐induced bone loss through regulation of both osteoblast and osteoclast differentiation. We examined effects of GSK‐3β inhibition on regulation of RANKL and OPG in a rat model of mechanical instability‐induced peri‐implant osteolysis. The rats were treated daily with a GSK‐3β inhibitor, AR28 (20 mg/kg bw), for up to 5 days. Bone tissue and blood serum were assessed by qRT‐PCR, immunohistochemistry, and ELISA on days 3 and 5, and by micro‐CT on day 5. After 3 days of treatment with AR28, mRNA levels of β‐catenin, Runx2, Osterix, Col1α1, and ALP were increased leading to higher osteoblast numbers compared to vehicle‐treated animals. BMP‐2 and Wnt16 mRNA levels were downregulated by mechanical instability and this was rescued by GSK‐3β inhibition. Osteoclast numbers were decreased significantly after 3 days of GSK‐3β inhibition, which correlated with enhanced OPG mRNA expression. This was accompanied by decreased serum levels of TRAP5b on days 3 and 5. Treatment with AR28 upregulated osteoblast differentiation, while osteoclastogenesis was blunted, leading to increased bone mass by day 5. These data suggest that GSK‐3β inactivation suppresses osteolysis through regulating both osteoblast and osteoclast differentiation in a rat model of instability‐induced osteolysis.

2014-03-01·Stem Cell Research4区 · 医学

Wnt-dependent osteogenic commitment of bone marrow stromal cells using a novel GSK3β inhibitor

4区 · 医学

ArticleOA

作者: O'Shea, Patrick J ; Fellgett, Simon W ; Pownall, Mary E ; Cook, David A ; Genever, Paul G

Bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) can differentiate into multiple lineages including osteogenic and adipogenic cells. Wnt signalling has been implicated in controlling BMSC fate, but the mechanisms are unclear and apparently conflicting data exist. Here we show that a novel glycogen synthase kinase 3β inhibitor, AR28, is a potent activator of canonical Wnt signalling using in vitro β-catenin translocation studies and TCF-reporter assays. In vivo, AR28 induced characteristic axis duplication and secondary regions of chordin expression in Xenopus laevis embryos. Using human BMSCs grown in adipogenic medium, we confirmed that AR28-mediated Wnt signalling caused a significant (p<0.05) dose-dependent reduction of adipogenic markers. In osteogenic media, including dexamethasone, AR28 caused significant (p<0.05) decreases in alkaline phosphatase (ALP) activity compared to vehicle controls, indicative of a reduced osteogenic response. However, when excluding dexamethasone from the osteogenic media, increases in both ALP and mineralisation were identified following AR28 treatment, which was blocked by mitomycin C. Pre-treatment of BMSCs with AR28 for 7 days before osteogenic induction also increased ALP activity and mineralisation. Furthermore, BMP2-induced osteogenic differentiation was strongly enhanced by AR28 addition within 3 days, but without concomitant changes in cell number, therefore revealing BMP-dependent and independent mechanisms for Wnt-induced osteogenesis.

100 项与 AR-28 相关的药物交易

登录后查看更多信息