Reversal of Osteoporotic Activity by Endothelial Cell-Secreted Bone Targeting and Biocompatible Exosomes

Targeting nanoparticles for diagnosis and therapy of bone tumors: Opportunities and challenges

A variety of targeted nanoparticles were developed for the diagnosis and therapy of orthotopic and metastatic bone tumors during the past decade. This critical review will focus on principles and methods in the design of these bone-targeted nanoparticles. Ligands including bisphosphonates, aspartic acid-rich peptides and synthetic polymers were grafted on nanoparticles such as PLGA nanoparticles, liposomes, dendrimers and inorganic nanoparticles for bone targeting. Besides, other ligands such as monoclonal antibodies, peptides and aptamers targeting biomarkers on tumor/bone cells were identified for targeted diagnosis and therapy. Examples of targeted nanoparticles for the early detection of bone metastatic tumors and the ablation of cancer via chemotherapy, photothermal therapy, gene therapy and combination therapy will be intensively reviewed. The development of multifunctional nanoparticles to break down the "vicious" cycle between tumor cell proliferation and bone resorption, and the challenges and perspectives in this area will be discussed.

Biological evaluation of bone substitute

Critical-sized defects (CSDs) caused by trauma, tumor resection, or skeletal abnormalities create a high demand for bone repair materials (BRMs). Over the years, scientists have been trying to develop BRMs and evaluate their efficacy using numerous developed methods. BRMs are characterized by osteogenesis and angiogenesis promoting properties, the latter of which has rarely been studied in vitro and in vivo. While blood vessels are required to provide nutrients. Bone mass maintains a dynamic balance under the joint action of osteolytic and osteogenic activity in which monocytes differentiate into osteolytic cells, and osteoprogenitor cells differentiate into osteogenic cells. This review would be helpful for inexperienced researchers as well as present a comprehensive overview of methods used to investigate the effect of BRMs on osteogenic cells, osteolytic cells, and blood vessels, as well as their biocompatibility and biological performance. This review is expected to facilitate further research and development of new BRMs.

Neobavaisoflavone inhibits osteoclastogenesis through blocking RANKL signalling-mediated TRAF6 and c-Src recruitment and NF-κB, MAPK and Akt pathways

Psoralea corylifolia (P corylifolia) has been popularly applied in traditional Chinese medicine decoction for treating osteoporosis and promoting fracture healing since centuries ago. However, the bioactive natural components remain unknown. In this study, applying comprehensive two-dimensional cell membrane chromatographic/C18 column/time-of-flight mass spectrometry (2D CMC/C18 column/TOFMS) system, neobavaisoflavone (NBIF), for the first time, was identified for the bioaffinity with RAW 264.7 cells membranes from the extracts of P corylifolia. Here, we revealed that NBIF inhibited RANKL-mediated osteoclastogenesis in bone marrow monocytes (BMMCs) and RAW264.7 cells dose dependently at the early stage. Moreover, NBIF inhibited osteoclasts function demonstrated by actin ring formation assay and pit-formation assay. With regard to the underlying molecular mechanism, co-immunoprecipitation showed that both the interactions of RANK with TRAF6 and with c-Src were disrupted. In addition, NBIF inhibited the phosphorylation of P50, P65, IκB in NF-κB pathway, ERK, JNK, P38 in MAPKs pathway, AKT in Akt pathway, accompanied with a blockade of calcium oscillation and inactivation of nuclear translocation of nuclear factor of activated T cells cytoplasmic 1 (NFATc1). In vivo, NBIF inhibited osteoclastogenesis, promoted osteogenesis and ameliorated bone loss in ovariectomized mice. In summary, P corylifolia-derived NBIF inhibited RANKL-mediated osteoclastogenesis by suppressing the recruitment of TRAF6 and c-Src to RANK, inactivating NF-κB, MAPKs, and Akt signalling pathways and inhibiting calcium oscillation and NFATc1 translocation. NBIF might serve as a promising candidate for the treatment of osteoclast-associated osteopenic diseases.

Exosome: a significant nano-scale drug delivery carrier

In recent years, due to the limitations of the nature of therapeutic agents, many synthetic nano-delivery systems have emerged to enhance the efficacy of drugs. Extracellular vesicles are currently a class of natural nano-scale drug carriers released by cells. As a tiny vesicle with a lipid bilayer membrane that can be secreted by most cells in the body, exosomes carry and transmit important signal molecules, Therefore, they have been a research hotspot in biomedicine and biomaterials due to their size advantages and huge potential in drug therapy. Many people are optimistic about the clinical application prospects of exosomes and are actively exploring the broad functions of exosomes and developing exosome therapeutic agents to make positive contributions to human health. In this review, we provide basic knowledge and focus on summarizing the advantages of exosomes as drug carriers, methods of loading drugs, targeting strategies, in vivo and in vitro tracing methods, and some of the latest developments in exosomes as drug carriers. In particular, the review provides an outlook for this field.

Advance in Drug Delivery for Ageing Skeletal Muscle

The age-related loss of skeletal muscle, sarcopenia, is characterized by progressive loss of muscle mass, reduction in muscle strength, and dysfunction of physical performance. It has become a global health problem leading to several adverse outcomes in the ageing population. Research on skeletal muscle loss prevention and treatment is developing quickly. However, the current clinical approaches to sarcopenia are limited. Recently, novel drug delivery systems offer new possibilities for treating aged muscle loss. Herein, we briefly recapitulate the potential therapeutic targets of aged skeletal muscle and provide a concise advance in the drug delivery systems, mainly focus on the use of nano-carriers. Furthermore, we elaborately discuss the prospect of aged skeletal muscle treatment by nanotechnology approaches.

The Emerging Role of Exosomal Non-coding RNAs in Musculoskeletal Diseases

Exosomes are phospholipid bilayer-enclosed membrane vesicles derived and constitutively secreted by various metabolically active cells. They are capable of mediating hetero- and homotypic intercellular communication by transferring multiple cargos from donor cells to recipient cells. Nowadays, non-coding RNAs (ncRNAs) have emerged as novel potential biomarkers or disease-targeting agents in a variety of diseases. However, the lack of effective delivery systems may impair their clinical application. Recently, accumulating evidence demonstrated that ncRNAs could be efficiently delivered to recipient cells using exosomes as a carrier, and therefore can exert a critical role in musculoskeletal diseases including osteoarthritis, rheumatoid arthritis, osteoporosis, muscular dystrophies, osteosarcoma and other diseases. Herein, we present an extensive review of biogenesis, physiological relevance and clinical implication of exosome-derived ncRNAs in musculoskeletal diseases.

Serum miR-222-3p as a Double-Edged Sword in Predicting Efficacy and Trastuzumab-Induced Cardiotoxicity for HER2-Positive Breast Cancer Patients Receiving Neoadjuvant Target Therapy

Background: We aimed to explore whether the expression of serum miR-222-3p might contribute to early prediction of therapeutic response, clinical outcomes, and adverse events for HER2-positive breast cancer patients receiving neoadjuvant therapy (NAT).

Methods: A total of 65 HER2-positive breast cancer patients receiving NAT were analyzed. The concentration of serum miR-222-3p was detected by quantitative real-time PCR. Logistic regression analysis was used to identify the association of serum miR-222-3p with pathological complete response (pCR). The relationship of serum miR-222-3p with disease-free survival (DFS) and overall survival (OS) was examined via log-rank test and Cox proportional hazards analysis. The ordered logistic regression was applied to evaluate the association between serum miR-222-3p and adverse events.

Results: The miR-222-3p low group was more likely to achieve pCR [odds ratio (OR) = 0.258, P = 0.043]. The interaction between miR-222-3p and presenting Ki67 level was also detected for pCR (OR = 49.230, P_interaction = 0.025). The miR-222-3p low group was correlated with superior DFS (P = 0.029) and OS (P = 0.0037). The expression of serum miR-222-3p was the independent protective factor for trastuzumab-induced cardiotoxicity (P < 0.05) and anemia (P = 0.013).

Conclusions: Serum miR-222-3p is the potential factor to predict pCR, survival benefit and trastuzumab-induced cardiotoxicity for HER2-positive breast cancer patients receiving NAT.

Lactulose Suppresses Osteoclastogenesis and Ameliorates Estrogen Deficiency-Induced Bone Loss in Mice

Postmenopausal osteoporosis is characterized by excess osteoclastogenesis which leads to net bone loss and brittle fractures. Studies have demonstrated that estrogen deficiency-associated bone loss is microbiota-dependent and could be prevented by probiotics and prebiotics. In this study, we report that orally administered lactulose (20 g/kg, 6 weeks) orally administered significantly inhibited osteoclastogenesis, bone resorption, and prevented ovariectomy (OVX)-induced bone loss in mice. Lactulose increased intestinal Claudin 2, 3 and 15, compared to the OVX group, and lowered pro-osteoclastogenic cytokines levels including tumor necrosis factor-α, interleukin(IL)-6, receptor activator of nuclear factor kappa-Β ligand (RANKL), and IL-17 as well as increased the anti-inflammatory cytokine IL-10 in the intestine, peripheral blood, and bone marrow. Lactulose significantly preserved the number of Foxp3⁺ Treg cells in the intestines compared with that in OVX mice. Lactulose altered the composition of intestinal microbiota measured by 16s rDNA sequencing and increased intestinal and serum short-chain fatty acids (SCFAs) levels including acetate, propionate and butyrate which were decreased in OVX mice as measured by gas chromatography. Oral administration of lactulose for 2 weeks significantly lowered the level of bone resorption marker C-telopeptide of type 1 collagen-1 in healthy male young volunteers (aging 20-25 years). In conclusion, lactulose inhibited osteoclastogenesis and bone resorption by altering the intestinal microbiota and increasing SCFAs. Lactulose could serve as an ideal therapeutic agent for postmenopausal osteoporosis.

Exosomes and Bone Disease

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Exosomes, which mediate cell-to-cell communications and provide a novel insight into information exchange, have drawn increasing attention in recent years. The homeostasis of bone metabolism is critical for bone health. The most common bone diseases such as osteoporosis, osteoarthritis and bone fractures have apparent correlations with exosomes. Accumulating evidence has suggested the potential regenerative capacities of stem cell-derived exosomes. In this review, we summarise the pathophysiological mechanism, clinical picture and therapeutic effects of exosomes in bone metabolism. We introduce the advantages and challenges in the application of exosomes. Although the exact mechanisms remain unclear, miRNAs seem to play major roles in the exosome.

The miR-193a-3p-MAP3k3 Signaling Axis Regulates Substrate Topography-Induced Osteogenesis of Bone Marrow Stem Cells

Substrate topographical features induce osteogenic differentiation of bone marrow stem cells (BMSCs), but the underlying mechanisms are unclear. As microRNAs (miRNAs) play key roles in osteogenesis and bone regeneration, it would be meaningful to elucidate the roles of miRNAs in the intracellular signaling cascade of topographical cue-induced osteogenic differentiation. In this study, the miRNA expression profile of the topographical feature-induced osteogenic differentiation group is different from that of the chemical-factors-induced osteogenic differentiation group. miR-193a-3p is sensitive to substrate topographical features and its downregulation enhances osteogenic differentiation only in the absence of osteogenesis-inducing medium. Also, substrate topographical features specifically activate a nonclassical osteogenetic pathway-the mitogen-activated protein kinase (MAPK) pathway. Loss- and gain-of-function experiments demonstrate that miR-193a-3p regulates the MAPK pathway by targeting the MAP3k3 gene. In conclusion, this data indicates that different osteogenic-lineage-related intracellular signaling cascades are triggered in BMSCs subjected to biophysical or chemical stimulation. Moreover, the miR-193a-3p-MAP3k3 signaling axis plays a pivotal role in the transduction of biophysical cues from the substrate to regulate the osteogenic lineage specification of BMSCs, and hence may be a promising molecular target for bone regenerative therapies.

l-tetrahydropalmatine suppresses osteoclastogenesis in vivo and in vitro via blocking RANK-TRAF6 interactions and inhibiting NF-κB and MAPK pathways

Bone homeostasis is delicately orchestrated by osteoblasts and osteoclasts. Various pathological bone loss situations result from the overactivated osteoclastogenesis. Receptor activator of nuclear factor κB ligand (RANKL)-activated NF-κB and MAPK pathways is vital for osteoclastogenesis. Here, we for the first time explored the effects of l-tetrahydropalmatine (l-THP), an active alkaloid derived from corydalis, on the formation and function of osteoclasts in vitro and in vivo. In RAW264.7 cells and bone marrow monocytes cells (BMMCs), l-THP inhibited osteoclastic differentiation at the early stage, down-regulated transcription level of osteoclastogenesis-related genes and impaired osteoclasts functions. Mechanically, Western blot showed that l-THP inhibited the phosphorylation of P50, P65, IκB, ERK, JNK and P38, and the electrophoretic mobility shift assay (EMSA) revealed that DNA binding activity of NF-κB was suppressed, ultimately inhibiting the expression of nuclear factor of activated T cells (NFATc1). Besides, Co-immunoprecipitation indicated that l-THP blocked the interactions of RANK and TNF receptor associated factor 6 (TRAF6) at an upstream site. In vivo, l-THP significantly inhibited ovariectomy-induced bone loss and osteoclastogenesis in mice. Collectively, our study demonstrated that l-THP suppressed osteoclastogenesis by blocking RANK-TRAF6 interactions and inhibiting NF-κB and MAPK pathways. l-THP is a promising agent for treating osteoclastogenesis-related diseases such as post-menopausal osteoporosis.

Hematoma-derived exosomes of chronic subdural hematoma promote abnormal angiogenesis and inhibit hematoma absorption through miR-144-5p

Exosomes are small (30-150 nm diameter) lipid bilayer-enclosed vesicles found in all bodily fluids. We investigated whether exosomes play a role in chronic subdural hematoma (CSDH). Exosomes were identified and characterized using transmission electron microscopy and NanoSight particle tracking. The functions of hematoma-derived exosomes were evaluated in a rat model of acute subdural hematoma (SDH). The hematoma-derived exosomes inhibited hematoma absorption and exacerbated neurological deficits in SDH rats. We examined the effects of the exosomes on angiogenesis and cell permeability in human umbilical vein endothelial cells (HUVECs). Co-culture of exosomes with HUVECs revealed that the hematoma-derived exosomes were taken-in by the HUVECs, resulting in enhanced tube formation and vascular permeability. Additionally, there was a concomitant increase in ANG-2 expression and decrease in ANG-1 expression. Exosomes were enriched with microRNAs including miR-144-5p, which they could deliver to HUVECs to promote angiogenesis and increase membrane permeability. Overexpression of miR-144-5p in HUVECs and in SDH rats promoted abnormal angiogenesis and reduced hematoma absorption, which mimicked the effects of the hematoma-derived exosomes both in vitro and in vivo. Thus, hematoma-derived exosomes promote abnormal angiogenesis with high permeability and inhibit hematoma absorption through miR-144-5p in CSDH.

The Role of Exosomes in Bone Remodeling: Implications for Bone Physiology and Disease

Bone remodeling represents a physiological phenomenon of continuous bone tissue renewal that requires fine orchestration of multiple cell types, which is critical for the understanding of bone disease but not yet clarified in precise detail. Exosomes, which are cell-secreted nanovesicles drawing increasing attention for their broad biosignaling functions, can shed new light on how multiple heterogeneous cells communicate for the purpose of bone remodeling. In the healthy bone, exosomes transmit signals favoring both bone synthesis and resorption, regulating the differentiation, recruitment, and activity of most cell types involved in bone remodeling and even assuming an active role in extracellular matrix mineralization. Additionally, in the ailing bone, they actively participate in pathogenic processes constituting also potential therapeutic agents and drug vectors. The present review summarizes the current knowledge on bone exosomes and bone remodeling in health and disease.

Up-regulated CST5 inhibits bone resorption and activation of osteoclasts in rat models of osteoporosis via suppression of the NF-κB pathway

Here, we aim at exploring the effect of CST5 on bone resorption and activation of osteoclasts in osteoporosis (OP) rats through the NF‐κB pathway. Microarray analysis was used to screen the OP‐related differentially expressed genes. Osteoporosis was induced in rats by intragastric retinoic acid administration. The serum levels of tartrate‐resistant acid phosphatase (TRAP), bone alkaline phosphatase (BALP) and osteocalcin (OC) and the expression of CD61 on the surface of osteoclasts were examined. The number of osteoclasts and the number and area of resorption pits were detected. Besides, the pathological changes and bone mineral density in bone tissues of rats were assessed. Also, the relationship between CST5 and the NF‐κB pathway was identified through determining the expression of CST5, RANKL, RANK, OPG, p65 and IKB. Poorly expressed CST5 was indicated to affect the OP. CST5 elevation and inhibition of the NF‐κB pathway decreased serum levels of TRAP, BALP and OC and expression of CD61 in vivo and in vitro. In OP rats, CST5 overexpression increased trabecular bones and bone mineral density of bone tissues, but decreased trabecular separation, fat within the bone marrow cavities and the number of osteoclasts through inhibiting the NF‐κB pathway. In vivo experiments showed that CST5 elevation inhibited growth in number and area of osteoclastic resorption pits and restrained osteoclastic bone absorption by inhibiting the NF‐κB pathway. In summary, overexpression of CST5 suppresses the activation and bone resorption of osteoclasts by inhibiting the activation of the NF‐κB pathway.

Extracellular vesicles in type 2 diabetes mellitus: key roles in pathogenesis, complications, and therapy

Type 2 diabetes mellitus (T2DM), a chronic disease, is widely prevalent all over the world. In recent years, the roles of some extracellular vesicles (EVs) in T2DM have attracted much attention. EVs are bilayer membrane vesicles secreted from most cells and can participate in regulating various physiological and pathological processes in vivo by being transported between cells. Recently, it was discovered that some abnormal EVs can contribute to the occurrence of T2DM by inducing insulin resistance and can also participate in the complications of T2DM. In addition, some stem/progenitor cells-derived EVs have a potential application in the therapy of T2DM. This review introduces basic concepts of EVs and summarizes the roles of EVs in the pathogenesis, complications, and therapy of T2DM.