Safranal inhibits estrogen-deficiency osteoporosis by targeting Sirt1 to interfere with NF-κB acetylation

AUTHORS

Sun-Ren Sheng, Yu-Hao Wu, Zi-Han Dai, Chen Jin, Gao-Lu He, Shu-Qing Jin, Bi-Yao Zhao, Xin Zhou, Cheng-Long Xie, Gang Zheng, Nai-Feng Tian

ABSTRACT

Background

Osteoporosis is a prevalent bone metabolic disease in menopause, and long-term medication is accompanied by serious side effects. Estrogen deficiency-mediated hyperactivated osteoclasts is the initiating factor for bone loss, which is regulated by nuclear factor-κB (NF-κB) signaling. Safranal (Saf) is a monoterpene aldehyde produced from Saffron (Crocus sativus L.) and possesses multiple biological properties, particularly the anti-inflammatory property. However, Saf's role in osteoporosis remains unknown.

Purpose

This study aims to validate the role of Saf in osteoporosis and explore the potential mechanism.

Study Design

The RANKL-exposed mouse BMM (bone marrow monocytes) and the castration-mediated osteoporosis model were applied to explore the effect and mechanism of Saf in vitro and in vivo.

Method

The effect of Saf on osteoclast formation and function were assessed by TRAcP staining, bone-resorptive experiment, qPCR, immunoblotting and immunofluorescence, etc. Micro-CT, HE, TRAcP and immunohistochemical staining were performed to estimate the effects of Saf administration on OVX-mediated osteoporosis in mice at imaging and histological levels.

Results

Saf concentration-dependently inhibited RANKL-mediated osteoclast differentiation without affecting cellular viability. Meanwhile, Saf-mediated anti-osteolytic capacity and Sirt1 upregulation were also found in ovariectomized mice. Mechanistically, Saf interfered with NF-κB signaling by activating Sirt1 to increase p65 deacetylation and inactivating IKK to decrease IκBα degradation.

Conclusion

Our results support the potential application of Saf as a therapeutic agent for osteoporosis.

MACF1 overexpression in BMSCs alleviates senile osteoporosis in mice through TCF4/miR-335–5p signaling pathway

AUTHORS

Kewen Zhang, Wuxia Qiu, Hui Li, Jun Li, Pai Wang, Zhihao Chen, Xiao Lin, Airong Qian

ABSTRACT

Background

The decreased osteogenic differentiation ability of mesenchymal stem cells (MSCs) is one of the important reasons for SOP. Inhibition of Wnt signaling in MSCs is closely related to SOP. Microtubule actin crosslinking factor 1 (MACF1) is an important regulator in Wnt/β-catenin signal transduction. However, whether the specific expression of MACF1 in MSC regulates SOP and its mechanism remains unclear.

Methods

We established MSC-specific Prrx1 (Prx1) promoter-driven MACF1 conditional knock-in (MACF-KI) mice, naturally aged male mice, and ovariectomized female mice models. Micro-CT, H&E staining, double calcein labeling, and the three-point bending test were used to explore the effects of MACF1 on bone formation and bone microstructure in the SOP mice model. Bioinformatics analysis, ChIP-PCR, qPCR, and ALP staining were used to explore the effects and mechanisms of MACF1 on MSCs’ osteogenic differentiation.

Results

Microarray analysis revealed that the expression of MACF1 and positive regulators of the Wnt pathway (such as TCF4, β-catenin, Dvl) was decreased in human MSCs (hMSCs) isolated from aged osteoporotic than non-osteoporotic patients. The ALP activity and osteogenesis marker genes (Alp, Runx2, and Bglap) expression in mouse MSCs was downregulated during aging. Furthermore, Micro-CT analysis of the femur from 2-month-old MSC-specific Prrx1 (Prx1) promoter-driven MACF1 conditional knock-in (MACF-cKI) mice showed no significant trabecular bone changes compared to wild-type littermate controls, whereas 18- and 21-month-old MACF1 c-KI animals displayed increased bone mineral densities (BMD), improved bone microstructure, and increased maximum compression stress. In addition, the ovariectomy (OVX)-induced osteoporosis model of MACF1 c-KI mice had significantly higher trabecular volume and number, and increased bone formation rate than that in control mice. Mechanistically, ChIP-PCR showed that TCF4 could bind to the promoter region of the host gene miR-335–5p. Moreover, MACF1 could regulate the expression of miR-335–5p by TCF4 during the osteogenic differentiation of MSCs.

Conclusion

These data indicate that MACF1 positively regulates MSCs osteogenesis and bone formation through the TCF4/miR-335-5p signaling pathway in SOP, suggesting that targeting MACF1 may be a novel therapeutic approach against SOP.

The translational potential of this article

MACF1, an important switch in the Wnt signaling pathway, can alleviate SOP through the TCF4/miR-335-5p signaling pathway in mice model. It might act as a therapeutic target for the treatment of SOP to improve bone function.

Randomized clinical study of injectable dextrin-based hydrogel as a carrier of a synthetic bone substitute

AUTHORS

Alexandra Machado, Isabel Pereira, Filomena Costa, Ana Brandão, José Eduardo Pereira, Ana Colette Maurício, José Domingos Santos, Inês Amaro, Rui Falacho, Rui Coelho, Nuno Cruz & Miguel Gama

ABSTRACT

Objectives

This study aimed to improve the performance and mode of administration of a glass-reinforced hydroxyapatite synthetic bone substitute, Bonelike by Biosckin® (BL®), by association with a dextrin-based hydrogel, DEXGEL, to achieve an injectable and moldable device named DEXGEL Bone.

Methods

Twelve participants requiring pre-molar tooth extraction and implant placement were enrolled in this study. BL® granules (250–500 µm) were administered to 6 randomized participants whereas the other 6 received DEXGEL Bone. After 6 months, a bone biopsy of the grafted area was collected for histological and histomorphometric evaluation, prior to implant placement. The performance of DEXGEL Bone and BL® treatments on alveolar preservation were further analyzed by computed tomography and Hounsfield density analysis. Primary implant stability was analyzed by implant stability coefficient technique.

Results

The healing of defects was free of any local or systemic complications. Both treatments showed good osseointegration with no signs of adverse reaction. DEXGEL Bone exhibited increased granule resorption (p = 0.029) accompanied by a tendency for more new bone ingrowth (although not statistically significant) compared to the BL® group. The addition of DEXGEL to BL® granules did not compromise bone volume or density, being even beneficial for implant primary stability (p = 0.017).

Conclusions

The hydrogel-reinforced biomaterial exhibited an easier handling, a better defect filling, and benefits in implant stability.

Clinical relevance

This study validates DEXGEL Bone safety and performance as an injectable carrier of granular bone substitutes for alveolar ridge preservation.

Trial registration

European Databank on Medical Devices (EUDAMED) No. CIV-PT-18–01-02,705; Registo Nacional de Estudos Clínicos, RNEC, No. 30122.

A Zeb1/MtCK1 metabolic axis controls osteoclast activation and skeletal remodeling

AUTHORS

Lingxin Zhu, Yi Tang, Xiao-Yan Li, Samuel A Kerk, Costas A Lyssiotis, Wenqing Feng, Xiaoyue Sun, Geoffrey E Hespe, Zijun Wang, Marc P Stemmler, Simone Brabletz, Thomas Brabletz, Evan T Keller, Jun Ma, Jung-Sun Cho, Jingwen Yang, Stephen J Weiss

ABSTRACT

Osteoclasts are bone-resorbing polykaryons responsible for skeletal remodeling during health and disease. Coincident with their differentiation from myeloid precursors, osteoclasts undergo extensive transcriptional and metabolic reprogramming in order to acquire the cellular machinery necessary to demineralize bone and digest its interwoven extracellular matrix. While attempting to identify new regulatory molecules critical to bone resorption, we discovered that murine and human osteoclast differentiation is accompanied by the expression of Zeb1, a zinc-finger transcriptional repressor whose role in normal development is most frequently linked to the control of epithelial-mesenchymal programs. However, following targeting, we find that Zeb1 serves as an unexpected regulator of osteoclast energy metabolism. In vivo, Zeb1-null osteoclasts assume a hyperactivated state, markedly decreasing bone density due to excessive resorptive activity. Mechanistically, Zeb1 acts in a rheostat-like fashion to modulate murine and human osteoclast activity by transcriptionally repressing an ATP-buffering enzyme, mitochondrial creatine kinase 1 (MtCK1), thereby controlling the phosphocreatine energy shuttle and mitochondrial respiration. Together, these studies identify a novel Zeb1/MtCK1 axis that exerts metabolic control over bone resorption in vitro and in vivo.

Sugar transporter Slc37a2 regulates bone metabolism in mice via a tubular lysosomal network in osteoclasts

AUTHORS

Pei Ying Ng, Amy B. P. Ribet, Qiang Guo, Benjamin H. Mullin, Jamie W. Y. Tan, Euphemie Landao-Bassonga, Sébastien Stephens, Kai Chen, Jinbo Yuan, Laila Abudulai, Maike Bollen, Edward T. T. T. Nguyen, Jasreen Kular, John M. Papadimitriou, Kent Søe, Rohan D. Teasdale, Jiake Xu, Robert G. Parton, Hiroshi Takayanagi & Nathan J. Pavlos

ABSTRACT

Osteoclasts are giant bone-digesting cells that harbor specialized lysosome-related organelles termed secretory lysosomes (SLs). SLs store cathepsin K and serve as a membrane precursor to the ruffled border, the osteoclast’s ‘resorptive apparatus’. Yet, the molecular composition and spatiotemporal organization of SLs remains incompletely understood. Here, using organelle-resolution proteomics, we identify member a2 of the solute carrier 37 family (Slc37a2) as a SL sugar transporter. We demonstrate in mice that Slc37a2 localizes to the SL limiting membrane and that these organelles adopt a hitherto unnoticed but dynamic tubular network in living osteoclasts that is required for bone digestion. Accordingly, mice lacking Slc37a2 accrue high bone mass owing to uncoupled bone metabolism and disturbances in SL export of monosaccharide sugars, a prerequisite for SL delivery to the bone-lining osteoclast plasma membrane. Thus, Slc37a2 is a physiological component of the osteoclast’s unique secretory organelle and a potential therapeutic target for metabolic bone diseases.

High-Energy, Whole-Body Proton Irradiation Differentially Alters Long-Term Brain Pathology and Behavior Dependent on Sex and Alzheimer’s Disease Mutations

AUTHORS

Robert G. Hinshaw, Maren K. Schroeder, Jason Ciola, Curran Varma, Brianna Colletti, Bin Liu, Grace Geyu Liu, Qiaoqiao Shi, Jacqueline P. Williams, M. Kerry O’Banion, Barbara J. Caldarone and Cynthia A. Lemere

ABSTRACT

Whole-body exposure to high-energy particle radiation remains an unmitigated hazard to human health in space. Ongoing experiments at the NASA Space Radiation Laboratory and elsewhere repeatedly show persistent changes in brain function long after exposure to simulations of this unique radiation environment, although, as is also the case with proton radiotherapy sequelae, how this occurs and especially how it interacts with common comorbidities is not well-understood. Here, we report modest differential changes in behavior and brain pathology between male and female Alzheimer’s-like and wildtype littermate mice 7–8 months after exposure to 0, 0.5, or 2 Gy of 1 GeV proton radiation. The mice were examined with a battery of behavior tests and assayed for amyloid beta pathology, synaptic markers, microbleeds, microglial reactivity, and plasma cytokines. In general, the Alzheimer’s model mice were more prone than their wildtype littermates to radiation-induced behavior changes, and hippocampal staining for amyloid beta pathology and microglial activation in these mice revealed a dose-dependent reduction in males but not in females. In summary, radiation-induced, long-term changes in behavior and pathology, although modest, appear specific to both sex and the underlying disease state.