Adipocyte-secreted factors increase osteoblast proliferation and the OPG/RANKL ratio to influence osteoclast formation

Osteoprotegerin mediates adipogenesis in obesity

INTRODUCTION

Adipogenesis, the process of white adipose tissue expansion, plays a critical role in the development of obesity. Osteoprotegerin (OPG), known for its role in bone metabolism regulation, emerges as a potential regulator in mediating adipogenesis during obesity onset.

OBJECTIVES

This study aims to elucidate the involvement of OPG in adipogenesis during the early phases of diet-induced obesity and explore its therapeutic potential in obesity management.

METHODS

Using a diet-induced obesity model, we investigated OPG expression patterns in adipocytes and explored the mechanisms underlying its involvement in adipogenesis. We also assessed the effects of targeted silencing of OPG and recombinant OPG administration on obesity progression and insulin resistance. Additionally, the impact of electroacupuncture treatment on OPG levels and obesity management was evaluated in both animal models and human participants.

RESULTS

OPG expression was prominently activated in adipocytes of white adipose tissues during the early phase of diet-induced obesity. Hyperlipidemia induced Cbfa1-dependent OPG transcription, initiating and promoting adipogenesis, leading to cell-size expansion and lipid storage. Intracellular OPG physically bound to RAR and released the PPARɤ/RXR complex, activating adipogenesis-associated gene expression. Targeted silencing of OPG suppressed obesity development, while recombinant OPG administration promoted disease progression and insulin resistance in obese mice. Electroacupuncture treatment suppressed obesity development in an OPG-dependent manner and improved obesity parameters in obese human participants.

CONCLUSION

OPG emerges as a key regulator in mediating adipogenesis during obesity development. Targeting OPG holds promise for the prevention and treatment of obesity, as evidenced by the efficacy of electroacupuncture treatment in modulating OPG levels and managing obesity-related outcomes.

Wnt16 Increases Bone-to-Implant Contact in an Osteopenic Rat Model by Increasing Proliferation and Regulating the Differentiation of Bone Marrow Stromal Cells

Osseointegration is a complex biological cascade that regulates bone regeneration after implant placement. Implants possessing complex multiscale surface topographies augment this regenerative process through the regulation of bone marrow stromal cells (MSCs) that are in contact with the implant surface. One pathway regulating osteoblastic differentiation is Wnt signaling, and upregulation of non-canonical Wnts increases differentiation of MSCs on these titanium substrates. Wnt16 is a non-canonical Wnt shown to regulate bone morphology in mouse models. This study evaluated the role of Wnt16 during surface-mediated osteoblastic differentiation of MSCs in vitro and osseointegration in vivo. MSCs were cultured on Ti substrates with different surface properties and non-canonical Wnt expression was determined. Subsequently, MSCs were cultured on Ti substrates +/-Wnt16 (100 ng/mL) and anti-Wnt16 antibodies (2 μg/mL). Wnt16 expression was increased in cells grown on microrough surfaces that were processed to be hydrophilic and have nanoscale roughness. However, treatment MSCs on these surfaces with exogenous rhWnt16b increased total DNA content and osteoprotegerin production, but reduced osteoblastic differentiation and production of local factors necessary for osteogenesis. Addition of anti-Wnt16 antibodies blocked the inhibitor effects of Wnt16. The response to Wnt16 was likely independent of other osteogenic pathways like Wnt11-Wnt5a signaling and semaphorin 3a signaling. We used an established rat model of cortical and trabecular femoral bone impairment following botox injections (2 injections of 8 units/leg each, starting and maintenance doses) to assess Wnt16 effects on whole bone morphology and implant osseointegration. Wnt16 injections did not alter whole bone morphology significantly (BV/TV, cortical thickness, restoration of trabecular bone) but were effective at increasing cortical bone-to-implant contact during impaired osseointegration in the botox model. The mechanical quality of the increased bone was not sufficient to rescue the deleterious effects of botox. Clinically, these results are important to understand the interaction of cortical and trabecular bone during implant integration. They suggest a role for Wnt16 in modulating bone remodeling by reducing osteoclastic activity. Targeted strategies to temporally regulate Wnt16 after implant placement could be used to improve osseointegration by increasing the net pool of osteoprogenitor cells.

Are the Properties of Bone Marrow-Derived Mesenchymal Stem Cells Influenced by Overweight and Obesity?

Bone marrow-derived mesenchymal stem cells (BMSCs) are promising candidates for cell-based therapies. Growing evidence has indicated that overweight/obesity can change the bone marrow microenvironment, which affects some properties of BMSCs. As the overweight/obese population rapidly increases, they will inevitably become a potential source of BMSCs for clinical application, especially when receiving autologous BMSC transplantation. Given this situation, the quality control of these cells has become particularly important. Therefore, it is urgent to characterize BMSCs isolated from overweight/obese bone marrow environments. In this review, we summarize the evidence of the effects of overweight/obesity on the biological properties of BMSCs derived from humans and animals, including proliferation, clonogenicity, surface antigen expression, senescence, apoptosis, and trilineage differentiation, as well as the underlying mechanisms. Overall, the conclusions of existing studies are not consistent. Most studies demonstrate that overweight/obesity can influence one or more characteristics of BMSCs, while the involved mechanisms are still unclear. Moreover, insufficient evidence proves that weight loss or other interventions can rescue these qualities to baseline status. Thus, further research should address these issues and prioritize developing methods to improve functions of overweight- or obesity-derived BMSCs.

Maternal omega-3 LC-PUFA supplementation programs an improved bone mass in the offspring with a more pronounced effect in females than males at adulthood

Early balanced nutrition is vital in achieving optimal skeletal mass and its maintenance. Although a lower omega-6 (n-6): omega-3 (n-3) long-chain polyunsaturated fatty acid (LC-PUFA) ratio is strongly linked with bone health, its maternal effect in the programming of the offspring's skeleton remains to be elucidated. Plugged C57BL/6 mice were fed either n-3 LC-PUFA Enriched Diet (LED) or a control diet (C) throughout their gestation and lactation. Offspring born to both the groups were weaned onto C till 6, 12, and 24 weeks of their age. Offspring's skeleton metabolism and serum fatty acid composition was studied. In humans, seventy-five mother-female newborns pairs from term gestation were tested for their maternal LC-PUFA status relationships to venous cord blood bone biomarkers. Offspring of maternal LED supplemented mice exhibited a superior bone phenotype over C, more prominent in females than males. A lower serum n-6/n-3 LC-PUFA in the LED group offspring was strongly associated with blood biomarkers of bone metabolism. Sexual dimorphism evidenced had a strong correlation between offspring's LC-PUFA levels and bone turnover markers in serum. A higher potential for osteoblastic differentiation in both LED offspring genders and reduced osteoclastogenesis in females was cell-autonomous effect. The human cross-sectional study also showed a positive correlation between maternal n-3 PUFA and cord blood markers of bone formation in female newborns at birth. Maternal dietary n-6/ n-3 fat quality determines offspring's bone growth and development. Our data suggest that the skeleton of female offspring is likely to be more sensitive to this early exposure.

IFT20 governs mesenchymal stem cell fate through positively regulating TGF-β-Smad2/3-Glut1 signaling mediated glucose metabolism

Aberrant lineage allocation of mesenchymal stem cells (MSCs) could cause bone marrow osteoblast-adipocyte imbalance, and glucose as an important nutrient is required for the maintenance of the MSCs' fate and function. Intraflagellar transport 20 (IFT20) is one of the IFT complex B protein which regulates osteoblast differentiation, and bone formation, but how IFT20 regulates MSCs' fate remains undefined. Here, we demonstrated that IFT20 controls MSC lineage allocation through regulating glucose metabolism during skeletal development. IFT20 deficiency in the early stage of MSCs caused significantly shortened limbs, decreased bone mass and significant increase in marrow fat. However, deletion of IFT20 in the later stage of MSCs and osteocytes just slightly decreased bone mass and bone growth and increased marrow fat. Additionally, we found that loss of IFT20 in MSCs promotes adipocyte formation, which enhances RANKL expression and bone resorption. Conversely, ablation of IFT20 in adipocytes reversed these phenotypes. Mechanistically, loss of IFT20 in MSCs significantly decreased glucose tolerance and suppressed glucose uptake and lactate and ATP production. Moreover, loss of IFT20 significantly decreased the activity of TGF-β-Smad2/3 signaling and reduced the binding activity of Smad2/3 to Glut1 promoter to downregulate Glut1 expression. These findings indicate that IFT20 plays essential roles for preventing MSC lineage allocation into adipocytes through TGF-β-Smad2/3-Glut1 axis.

Upregulation of osteoprotegerin inhibits tert-butyl hydroperoxide-induced apoptosis of human chondrocytes

Necrosis of the femoral head (NFH) is an orthopedic disease characterized by a severe lack of blood supply to the femoral head and a marked increase in intraosseous pressure. NFH is associated with numerous factors, such as alcohol consumption and hormone levels. The present study focused on the expression levels of osteoprotegerin (OPG) in NFH and the effect of OPG overexpression on chondrocyte apoptosis. The results demonstrated that OPG expression was markedly decreased in the femoral head of patients with NFH compared with normal femoral heads. Lentivirus-mediated overexpression of OPG in human chondrocytes reversed the decrease in cell viability and the increase in reactive oxygen species production induced by an oxidative stress-inducing factor, tert-butyl hydroperoxide. Flow cytometry and TUNEL assays revealed that OPG overexpression inhibited the apoptosis of chondrocytes. In addition, it was revealed that OPG exerted its anti-apoptotic effect mainly by promoting Bcl-2 expression and Akt phosphorylation and inhibiting caspase-3 cleavage and Bax expression. The present study revealed that OPG may be an important regulator of NFH.

Cod Liver Oil, but Not Retinoic Acid, Treatment Restores Bone Thickness in a Vitamin A-Deficient Rat

Vitamin A plays a prominent role for maintaining optimal bone status, but its impact upon the bone in response to vitamin A deficiency is not well defined. The purpose of this study was to evaluate how replenishing vitamin A by either whole food cod liver oil (COD) or the active metabolite of vitamin A, retinoic acid (RA), altered bone thickness of vitamin A-deficient (VAD) rats. Weanling rats were administered a control diet (CTRL) or VAD diet for 9 weeks. This was followed by four weeks of treatment in which the VAD group was divided into the following 4 subgroups: (1) VAD (9 weeks)-VAD (4 weeks); (2) VAD-CTRL; (3) VAD-COD; and (4) VAD-RA. Compared to controls, VAD rats had thicker bones which showed marked dysplasia. VAD-rats treated with COD produced a thinner bone that was not significantly different from that of untreated rats. In contrast, RA did not significantly change the thicker bone, and also had significantly greater periosteal and endosteal osteoblast numbers compared to VAD-COD. Active osteoclasts were not detected in VAD rats, nor during the treatment period. These findings suggest that the abnormal bone thickness in VAD rats appears to be more effectively restored to bone thickness of untreated control rats when treated with COD.

Association of Specific Genetic Polymorphisms with Atraumatic Osteonecrosis of the Femoral Head: A Narrative Review

INTRODUCTION

Atraumatic ONFH is one of the leading cause of hip morbidity in the working-age group. It is a multi-factorial disease whose root cause can be attributed to single-nucleotide polymorphism. Identifying such polymorphisms could pave the way for new modalities of treatment for ONFH.

METHODOLOGY

Two databases were electronically searched for relevant articles. The articles were screened through titles, abstract and full texts to include the relevant studies. A secondary search was done through the reference list of selected articles.

RESULTS

A total of 52 studies were included among the 181 hits. All 181 were case-control studies. Summary of these studies identifies multiple SNPs which can cause ONFH. There were 117 SNPs in all 181 studies, of which 92 were associated with the causation of ONFH and 25 were protective against ONFH.

CONCLUSION

SNPs play an essential role in causing atraumatic ONFH. Identification of SNP that contribute to causing ONFH may help reduce the disease burden by early identification, diagnosis and treatment, including targeted gene therapy.

Ferulic acid attenuates osteoporosis induced by glucocorticoid through regulating the GSK-3β/Lrp-5/ERK signalling pathways

Objective

To evaluate in-vivo and in-vitro effects of ferulic acid (FA) on glucocorticoid-induced osteoarthritis (GIO) to establish its possible underlying mechanisms.

Methods

The effects of FA on cell proliferation, cell viability (MTT assay), ALP activity, and mineralization assay, and oxidative stress markers (ROS, SOD, GSH LDH and MDA levels) were investigated by MC3T3-E1 cell line. Wistar rats received standard saline (control group) or dexamethasone (GC, 2 mg-1 kg) or DEX+FA (50 and 100 mg-1 kg) orally for 8 weeks. Bone density, micro-architecture, bio-mechanics, bone turnover markers and histo-morphology were determined. The expression of OPG, RANKL, osteogenic markers, and other signalling proteins was assessed employing quantitative RT-PCR and Western blotting.

Results

The findings indicated the elevation of ALP mRNA expressions, osteogenic markers (Runx-2, OSX, Col-I, and OSN), and the β-Catenin, Lrp-5 and GSK-3β protein expressions. FA showed the potential to increase MC3T3-E1 cell differentiation, proliferation, and mineralization. FA increased oxidative stress markers (SOD, MDA, and GSH) while decreasing ROS levels and lactate dehydrogenase release in GIO rats. The OPG/RANKL mRNA expression ratio was increased by FA, followed by improved GSK-3β and ERK phosphorylation with enhanced mRNA expressions of Lrp-5 and β-catenin.

Conclusion

These findings showed that FA improved osteoblasts proliferation with oxidative stress suppression by controlling the Lrp-5/GSK-3β/ERK pathway in GIO, demonstrating the potential pathways involved in the mechanism of actions of FA in GIO therapy.

Effects of Bacillus subtilis on Production Performance, Bone Physiological Property, and Hematology Indexes in Laying Hens

Simple Summary

Due to breeding for high egg production, laying hens are at great risk for developing osteoporosis. To develop an effective feed additive for reducing the bone damage and associated pain and economic loss has become a critical issue affecting the poultry industry. The aim of this study was to investigate the effects of Bacillus subtills as a feed supplement on production performance and bone pathophysiological characteristics of laying hens. The results showed that Bacillus subtilis increases marketable eggs, protects bone health, changes the distribution of phosphorus between blood and bone, and increases estrogen but decreases interleukin-1 and tumor necrosis factor-α concentrations in blood. Results indicate that Bacillus subtilis can be used as a dietary supplement to increase marketable egg production and bone health of laying hens by inhibiting gut and systemic inflammation via the microbiota-gut-immune and the microbiota-gut-bone axes.

Abstract

This study was to investigate the effects of Bacillus subtilis on production performance and bone pathophysiological characteristics of layers. Twenty-four 48-week-old Lohmann Pink-shell laying hens were randomly divided into two groups: a basic diet (control) and the basic diet mixed with Bacillus subtilis (0.5 g/kg) for a 60-day trial. Statistically, independent-sample t-test was used to assess the treatment differences. The results showed that Bacillus subtilis supplementation improved the percent of marketable eggs (p < 0.05) with reduced numbers of broken and soft-shelled eggs but had no effects on egg weight, height of albumen, yolk color, and Haugh unit (p > 0.05). Bacillus subtilis supplement also elevated maximum load (p = 0.06), maximum stress (p = 0.01), stiffness (p < 0.01), and Young’s modulus (p < 0.01) but suppressed maximum strain (p = 0.06) in the femur. In addition, compared with control birds, phosphorous concentration (p < 0.01) was reduced in serum at day 61 but increased in the femur (p < 0.05) in Bacillus subtilis fed birds. Bacillus subtilis fed birds also had lower magnesium concentrations in both femur (p = 0.04) and feces (p = 0.09). Furthermore, Bacillus subtilis increased plasma estrogen concentration (p = 0.01) and femur TNF receptor superfamily member 11b (OPG) expression (p < 0.05) but reduced plasma IL-1 (p < 0.01) and TNF-α (p < 0.01) concentrations. These results indicate that Bacillus subtilis could be used as a health promotor to reduce overproduction-induced inflammation and associated bone damage and to increase marketable egg production. The data provide evidence for developing a management strategy to use Bacillus subtilis as a feed additive to improve marketable egg production and health and welfare status of laying hens.

Age and Interleukin-15 Levels Are Independently Associated With Intima-Media Thickness in Obesity-Related NAFLD Patients

Common carotid intima-media thickness (IMT) represents a functional and structural marker of early, precocious, and subclinical atherosclerosis, independently from the carotid plaque. Macrophage cells, which have been detected in adipose tissue and atherosclerotic plaques, are regulated by interleukin-15 (IL-15). At the light of the conflicting results concerning the role of IL-15 in atherosclerosis, the aim of the study was to retrospectively evaluate in a population of 80 obese patients, with median age of 46 years (IQR 34–53 years), with a low rate of comorbidities but with non-alcoholic fatty liver disease (NAFLD) or hepatic steatosis (HS), the relationship between IMT and serum concentrations of IL-15. Anthropometric measures, metabolic profile, and serum inflammatory markers, as well as the levels of IL-15, MCP-1, b FGF, and GM-CSF, were analyzed by a bead-based assay. IMT, HS, subcutaneous, and visceral adipose tissues were detected by ultrasonography. The IL-15 levels of the obese patients were increased with respect to those of 44 young healthy subjects, i.e., 2.77 (1.21–4.8) vs. 1.55 (1–2.4) pg/mL (P = 0.002). In the univariate analysis, IL-15 levels were associated to IMT and to those of MCP-1, b FGF, and GM-CSF, without any relation to other inflammatory markers such as CRP and ferritin, except fibrinogen. In the multivariate analysis, after adjusting the HS severity for the extent of visceral adiposity, a dramatic change in prediction of IMT by HS was shown (β from 0.29 to 0.10, P from 0.008 to 0.37). When the visceral adipose tissue was combined with IL-15, on the one hand, and the well-known coronary artery disease (CAD) risk factors—i.e., age, gender, smoking status, HDL-cholesterol concentrations, triglycerides levels, and HOMA—on the other, only age and IL-15 remained the predictors of IMT (β = 0.60, P = 0.0001 and β = 0.25, P = 0.024, respectively). There was no association of IL-15 with various anthropometric parameters nor with body fat distribution and severity of HS, also after adjusting for age. Age is resulted to be the main factor in the prediction of IMT and thus of early atherosclerosis. The prediction of IMT by IL-15 coupled with the lack of prediction by the well-known CAD risks is in agreement with recent data, which emphasizes the main role of the immune system in the onset/worsening of atherosclerosis, even though the role of visceral adiposity should be further deepened. Age and IL-15 levels were both predictors of early atherosclerosis in this population of obese patients with NAFLD, suggesting a possible role of this cytokine in the atherosclerosis process.

A temporal study on musculoskeletal morphology and metabolism in hibernating Daurian ground squirrels (Spermophilus dauricus)

Hibernators provide a natural model to study the mechanisms underlying the prevention of disuse-induced musculoskeletal deterioration. Currently, however, these mechanisms remain poorly understood. Here, we investigated changes in morphology and metabolic indices in the hindlimb skeletal muscle and bone of Daurian ground squirrels (Spermophilus dauricus) during different periods of hibernation, and further explored the possible mechanisms involved in the musculoskeletal maintenance of hibernators after prolonged inactivity. Results showed that, compared with levels in the summer active group (SA), almost all morphological indices of skeletal muscle and bone, including muscle mass, muscle fiber cross-sectional area, bone mass, bone length, and bone mechanical properties, were unchanged in the different periods of hibernation. Only a few microstructural parameters of bone showed deterioration in the post-hibernation group (POST), including increased specific bone surface (+71%), decreased trabecular thickness (-43%), and decreased average cortical thickness (-51%) in the tibia, and increased trabecular separation (+60%) in the femur. Furthermore, most examined metabolic indices involved in muscle protein turnover and bone remodeling were unchanged, except for several indices in the inter-bout arousal group (IBA), i.e., increase in the phosphorylation of eukaryotic initiation factor 4E binding protein 1 (4E-BP1) (IBA vs. SA, +80%) in the vastus medialis muscle, increase in chymotrypsin-like activity (IBA vs. SA, +62%) in the tibialis anterior muscle, increase in osteoblast number (IBA vs. SA, +110%; IBA vs. torpor (TOR), +68%) and osteoclast number (IBA vs. TOR, +105%) per bone surface in the tibia, and increase in osteoclast surface per bone surface (IBA vs. TOR, +128%) in the femur. The above evidence demonstrates that the musculoskeletal morphology of squirrels was largely preserved, and musculoskeletal metabolism was generally maintained after prolonged hibernation inactivity. These findings suggest that the well-maintained musculoskeletal metabolism may be a vital mechanism underlying the preservation of the musculoskeletal system during hibernation. The coincident up-regulation of several metabolic indicators during IBA indicates that musculoskeletal metabolism may be relatively active during this period; however, its role in musculoskeletal maintenance during hibernation needs further clarification.

Molecular insights into the interplay between adiposity, breast cancer and bone metastasis

Cancer is a complex disease, with various pre-existing health ailments enhancing its pathology. In cancer, the extracellular environment contains various intrinsic physiological factors whose levels are altered with aging and pre-existing conditions. In obesity, the tumor microenvironment and metastases are enriched with factors that are both derived locally, and from other physiological compartments. Similarly, in obesity, the cancer cell environment both at the site of origin and at the secondary site i.e., metastatic niche, contains significantly more phenotypically-altered adipocytes than that of un-obese cancer patients. Indeed, obesity has been linked with cancer progression, metastasis, and therapy resistance. Adipocytes not only interact with tumor cells, but also with adjacent stromal cells at primary and metastatic sites. This review emphasizes the importance of bidirectional interactions between adipocytes and breast tumor cells in breast cancer progression and its bone metastases. This paper not only chronicles the role of various adipocyte-derived factors in tumor growth, but also describes the significance of adipocyte-derived bone metastatic factors in the development of bone metastasis of breast cancer. It provides a molecular view of the interplay between the adipocytes and tumor cells involved in breast cancer bone metastasis. However, more research is needed to determine if targeting cancer-associated adipocytes holds promise as a potential therapeutic approach for breast cancer bone metastasis treatment. Interplay between adipocytes and breast cancer cells at primary cancer site and metastatic bone microenvironment. AMSC Adipose-derived mesenchymal stem cell, CAA Cancer associated adipocytes, CAF Cancer associated fibroblast, BMSC Bone marrow derived mesenchymal stem cell, BMA Bone marrow adipocyte.

Preventive Effects of Chrysanthemum coronarium L. Extract on Bone Metabolism In Vitro and In Vivo

Osteoporosis is characterized by decreased bone mass and bone microarchitectural failure, leading to an enhanced risk of bone fractures. Chrysanthemum coronarium L. (CC) is a natural plant with powerful antioxidant activity. This study investigated the antiosteoporotic effects of CC extracts in in vitro cell cultures and in vivo bone loss animal models. CC stimulated osteoblast differentiation and mineralized bone formation by osteoblasts by increasing the expression of bone formation markers (alkaline phosphatase, osteoprotegerin, and osteoprotegerin/receptor activator nuclear factor-κB ligand ratio) in the murine preosteoblastic cell line MC3T3-E1. Additionally, CC was found to inhibit osteoclast differentiation by downregulating bone resorption markers (tartrate-resistant acid phosphatase, cathepsin K, dendritic cell-specific transmembrane protein, and calcitonin receptor) in the murine macrophage-like cell line RAW264.7. CC prevented ovariectomy-induced bone loss, preserved trabecular microarchitecture, and improved serum bone turnover markers in an osteoporotic mouse model. These findings suggest that CC extract may be considered as a natural therapeutic or preventive agent for osteoporotic bone loss.

Fibroblast growth factor 2 exacerbates inflammation in adipocytes through NLRP3 inflammasome activation

Chronic inflammation in adipose tissue is the hallmark of obesity and a major risk factor for the development of obesity-induced insulin resistance. NLRP3 inflammasome regulates the maturation and secretion of pro-inflammatory cytokines, such as IL-1β and IL-18, and was recently discovered to be involved in obesity-related metabolic diseases. Fibroblast growth factors (FGFs) such as FGF1, FGF10, and FGF21 are adipokines that regulate adipocyte development and metabolism, but reports on the effect of other FGFs on adipocytes are lacking. In the present study, the novel role of FGF2 in NLRP3 inflammasome activation was elucidated. Our results showed that FGF2 levels were increased during adipocyte differentiation and in the adipose tissue of high-fat diet (HFD)-induced obese mice. Recombinant FGF2 treatment upregulated inflammasome markers such as NLRP3, which was further exaggerated by TNF-ɑ treatment. Interestingly, β-Klotho, a co-receptor of FGF21, was significantly decreased by FGF2 treatment. Results from mice confirmed the positive correlation between FGF2 and NLRP3 expression in epididymal and subcutaneous adipose tissue, while exercise training effectively reversed HFD-induced NLRP3 expression as well as FGF2 levels in both adipose depots. Our results suggest that FGF2 is an adipokine that may exacerbate the inflammatory response in adipocytes through NLRP3 inflammasome activation.

bFGF promotes neurological recovery from neonatal hypoxic-ischemic encephalopathy by IL-1β signaling pathway-mediated axon regeneration

INTRODUCTION

Neonatal hypoxia-ischemic brain damage (HIBD) can lead to serious neuron damage and dysfunction, causing a significant worldwide health problem. bFGF as a protective reagent promotes neuron repair under hypoxia/ischemia (HI). However, how bFGF and downstream molecules were regulated in HI remains elusive.

METHODS

We established an in vitro HI model by culturing primary cortical neurons and treated with oxygen-glucose deprivation (OGD). We suppressed the expression of bFGF by using siRNA (small interfering RNA) interference to detect the neuronal morphological changes by immunofluorescence staining. To determine the potential mechanisms regulated by bFGF, the change of downstream molecular including IL-1β was examined in bFGF knockdown condition. IL-1β knockout (KO) rats were generated using CRISPR/Cas9-mediated technologies. We used an accepted rat model of HI, to assess the effect of IL-1β deletion on disease outcomes and carried out analysis on the behavior, histological, cellular, and molecular level.

RESULTS

We identified that OGD can induce endogenous expression of bFGF. Both OGD and knockdown of bFGF resulted in reduction of neuron numbers, enlarged cell body and shortened axon length. We found molecules closely related to bFGF, such as interleukin-1β (IL-1β). IL-1β was up-regulated after bFGF interference under OGD conditions, suggesting complex signaling between bFGF and OGD-mediated pathways. We found HI resulted in up-regulation of IL-1β mRNA in cortex and hippocampus. IL-1β KO rats markedly attenuated the impairment of long-term learning and memory induced by HI. Meanwhile, IL-1β^-/- (KO, homozygous) group showed better neurite growth and less apoptosis in OGD model. Furthermore, serine/threonine protein kinase (AKT1) mRNA and protein expression was significantly up-regulated in IL-1β KO rats.

CONCLUSIONS

We showed that IL-1β-mediated axon regeneration underlie the mechanism of bFGF for the treatment of HIBD in neonatal rats. Results from this study would provide insights and molecular basis for future therapeutics in treating HIBD.

The PPAR-γ antagonist T007 inhibits RANKL-induced osteoclastogenesis and counteracts OVX-induced bone loss in mice

Background

Osteoclasts are key determinant cellular components implicated in the development and progression of disorders driven by bone damage. Herein, we studied the upshot of T007, an antagonist of peroxisome proliferator-activated receptor-gamma (PPARγ), on osteoclastogenesis using cell and animal models.

Results

The in vitro assays revealed that T007 hindered the osteoclastogenesis caused by the treatment with the receptor activator of nuclear factor-κB ligand (RANKL) through inhibiting the levels of PPARγ in cells. The PPARγ siRNA partially reproduced the inhibitory action of T007. The opposite findings were produced after PPARγ overexpression. Furthermore, T007 prevented from bone loss in a mouse model of osteoporosis induced by ovariectomy (OVX). These findings implied that T007 is a potential efficient drug for the prophylaxis and cure of osteoclast-related disorders.

Conclusions

Taken together, our findings demonstrated that T007 impedes osteoclastogenesis and will be useful for the therapy of bone related diseases, essentially osteoporosis.

Association of Variant Interactions in RANK, RANKL, OPG, TRAF6, and NFATC1 Genes with the Development of Osteonecrosis of the Femoral Head

Multiple gene polymorphisms have been demonstrated to correlate with the susceptibility to osteonecrosis of the femoral head (ONFH). However, as a complex disease induced by multiple genes, the development of ONFH has rarely been reported to involve in gene interaction. In this study, we first explored the association of 10 variants interactions in receptor activator of nuclear factor-kappa B (RANK), RANK ligand (RANKL), osteoprotegerin (OPG), tumor necrosis factor receptor-associated factor 6 (TRAF6), and nuclear factor of activated T cells cytoplasmic 1 (NFATC1) genes with the development and clinical phenotypes of ONFH in a 377 ONFH case-control study with using Mass ARRAY^® platform. Our results showed that not only a total of 6 interactional variants in the paired 10 variants interactions were significantly associated with the development of ONFH (OPG rs2073617 and NFATC1 rs754093, p < 0.019; OPG rs2073618 and NFATC1 rs754093, p < 0.008; OPG rs2073617 and RANKL rs1054016, p < 0.039, respectively) but also a total of 4 paired interactional variants were found to involve significantly in the increased risk of bilateral hip lesions in ONFH (OPG rs2073617 and TRAF6 rs5030411, p = 0.044; RANK rs884205 and TRAF6 rs5030411, p = 0.045, respectively). Moreover, the results from generalized multifactor dimensionality reduction also showed that the five best models were identified and associated significantly with ONFH risk, p = 0.001, 0.01, 0.01, 0.01, and 0.01, respectively. Our results first suggest that the variants in RANK/RANKL/OPG pathway genes affected the development of ONFH in gene interaction manner through the interaction of the paired variants and multiple variants.

Treatment with an inhibitor of fatty acid synthase attenuates bone loss in ovariectomized mice

Bone and fat cells have an antagonistic relationship. Adipocytes exert a toxic effect on bone cells in vitro through the secretion of fatty acids, which are synthesized by fatty acid synthase (FAS). Inhibition of FAS in vitro rescues osteoblasts from fat-induced toxicity and cell death. In this study, we hypothesized that FAS inhibition would mitigate the loss of bone mass in ovariectomized (OVX) mice. We treated OVX C57BL/6 mice with cerulenin (a known inhibitor of FAS) for 6 weeks and compared their bone phenotype with vehicle-treated controls. Cerulenin-treated mice exhibited a significant decrease in body weight, triglycerides, leptin, and marrow and subcutaneous fat without changes in serum glucose or calciotropic hormones. These effects were associated with attenuation of bone loss and normalization of the bone phenotype in the cerulenin-treated OVX group compared to the vehicle-treated OVX group. Our results demonstrate that inhibition of FAS enhances bone formation, induces uncoupling between osteoblasts and osteoclasts, and favors mineralization, thus providing evidence that inhibition of FAS could constitute a new anabolic therapy for osteoporosis.

Injectable Allograft Adipose Matrix Supports Adipogenic Tissue Remodeling in the Nude Mouse and Human

Supplemental Digital Content is available in the text.

Background:

Adipose tissue reaches cellular stasis after puberty, leaving adipocytes unable to significantly expand or renew under normal physiologic conditions. This is problematic in progressive lipodystrophies, in instances of scarring, and in soft-tissue damage resulting from lumpectomy and traumatic deformities, because adipose tissue will not self-renew once damaged. This yields significant clinical necessity for an off-the-shelf de novo soft-tissue replacement mechanism.

Methods:

A process comprising separate steps of removing lipid and cellular materials from adipose tissue has been developed, creating an ambient temperature-stable allograft adipose matrix. Growth factors and matrix proteins relevant to angiogenesis and adipogenesis were identified by enzyme-linked immunosorbent assay and immunohistochemistry, and subcutaneous soft-tissue integration of the allograft adipose matrix was investigated in vivo in both the athymic mouse and the dorsum of the human wrist.

Results:

Allograft adipose matrix maintained structural components and endogenous growth factors. In vitro, adipose-derived stem cells cultured on allograft adipose matrix underwent adipogenesis in the absence of media-based cues. In vivo, animal modeling showed vasculature formation followed by perilipin A–positive tissue segments. Allograft adipose matrix maintained soft-tissue volume in the dorsal wrist in a 4-month investigation with no severe adverse events, becoming palpably consistent with subcutaneous adipose.

Conclusions:

Subcutaneous implantation of allograft adipose matrix laden with retained angiogenic and adipogenic factors served as an inductive scaffold for sustaining adipogenesis. Tissue incorporation assessed histologically from both the subcutaneous injection site of the athymic nude mouse over 6 months and human dorsal wrist presented adipocyte morphology residing within the injected scaffold.

Effects of constrained dynamic loading, CKIP‑1 gene knockout and combination stimulations on bone loss caused by mechanical unloading

Mechanical stimulation plays an important role in maintaining the growth and normal function of the skeletal system. Mechanical unloading occurs, for example, in astronauts spending long periods of time in space or in patients on prolonged bed rest, and causes a rapid loss of bone mass. Casein kinase 2‑interacting protein‑1 (CKIP‑1) is a novel negative bone regulation factor that has been demonstrated to reduce bone loss and enhance bone formation. The aim of this study was to investigate the effect of constrained dynamic loading (Loading) in combination with CKIP‑1 gene knockout (KO) on unloading‑induced bone loss in tail‑suspension mice. The blood serum metabolism index [alkaline phosphatase (ALP) activity and osteocalcin (OCN) levels], tibia mechanical behavior (including bone trabecular microstructure parameters and tibia biomechanical properties), osteoblast‑related gene expression [ALP, OCN, collagen I and bone morphogenetic protein‑2 and osteoprotegerin (OPG)] and osteoclast‑related gene expression [receptor activators of NF‑kB ligand (RANKL)] were measured. The results demonstrated that mice experienced a loss of bone mass after four weeks of tail suspension compared with a wild type group. The mechanical properties, microarchitecture and mRNA expression were significantly increased in mice after Loading + KO treatment (P<0.05). Furthermore, compared with loading or KO alone, the ratio of OPG/RANKL was increased in the combined treatment group. The combined effect of Loading + KO was greater than that observed with loading or KO alone (P<0.05). The present study demonstrates that Loading + KO can counter unloading‑induced bone loss, and combining the two treatments has an additive effect. These results indicate that combined therapy could be a novel strategy for the clinical treatment of disuse osteoporosis associated with space travel or bed rest.

Role of Wnt11 during Osteogenic Differentiation of Human Mesenchymal Stem Cells on Microstructured Titanium Surfaces

Successful osseointegration of an endosseous implant involves migration and differentiation of mesenchymal stem cells (MSCs) on the implant surface. Micro-structured, hydrophilic titanium surfaces direct MSCs to undergo osteoblastic differentiation in vitro, in the absence of media additives commonly used in cultures grown on tissue culture polystyrene (TCPS). This process involves non-canonical Wnt5a, in contrast to canonical Wnt3a typically credited with osteoblastic differentiation on TCPS. Wnt proteins have been implicated in morphological development and tissue patterning, suggesting that additional Wnts may participate. Here, we demonstrate that Wnt11 is a mediator of osteoblast commitment of MSCs, and increases in a surface-roughness dependent manner. Experiments using cells silenced for Wnt11 indicate that cross-talk between Wnt5a and Wnt11 occurs. Wnt11 potentially acts upstream to Wnt5a, increasing Wnt5a expression and factors associated with osteogenesis. Thus, Wnt11 contributes to peri-implant bone formation distal to the implant surface through a heavily regulated signaling cascade of autocrine/paracrine proteins.

Morinda citrifolia L. Leaf Extract Protects against Cerebral Ischemia and Osteoporosis in an In Vivo Experimental Model of Menopause

We aimed to determine the protective effects against cerebral ischemia and osteoporosis of Morinda citrifolia extract in experimental menopause. The neuroprotective effect was assessed by giving M. citrifolia leaf extract at doses of 2, 10, and 50 mg/kg BW to the bilateral ovariectomized (OVX) rats for 7 days. Then, they were occluded in the right middle cerebral artery (MCAO) for 90 minutes. The neurological score, brain infarction volume, oxidative stress status, and ERK1/2 and eNOS activities were assessed 24 hours later. M. citrifolia improved neurological score, brain infarction, and brain oxidative stress status in the cortex of OVX rats plus the MCAO. No changes in ERK 1/2 signal pathway and NOS expression were observed in this area. Our data suggested that the neuroprotective effect of the extract might occur partly via the improvement of oxidative stress status in the cortex. The antiosteoporotic effect in OVX rats was also assessed after an 84-day intervention of M. citrifolia. The serum levels of calcium, osteocalcin, and alkaline phosphatase and osteoblast density in the tibia were increased, but the density of osteoclast was decreased in OVX rats which received the extract. Therefore, the current data suggested that the extract possessed antiosteoporotic effect by increasing bone formation but decreasing bone resorption.

The Combination of icariin and constrained dynamic loading stimulation attenuates bone loss in ovariectomy-induced osteoporotic mice

Osteoporosis is a disease characterized by low bone mass and progressive destruction of bone microstructure, resulting in increasing the risk of fracture. Icariin (ICA) as a phytoestrogen shows osteogenic effects, and the mechanical stimulation has been demonstrated the improving effect on osteoporosis. The objective of this study was to investigate the effect of ICA in combination with constrained dynamic loading (CDL) stimulation on osteoporosis in ovariectomized (OVX) mice. The serum hormone levels, bone turnover markers, trabecular architecture, ulnar biomechanical properties, and the expression of osteoblast-related gene (alkaline phosphatase, ALP; osteocalcin, OCN; bone morphogenetic protein-2, BMP-2; Collagen I (α1), COL1; osteoprotegerin, OPG) and osteoclast-related genes (receptor activators of NF-κB ligand, RANKL; tartrate-resistant acid phosphatase, TRAP) were analyzed. The results showed that ICA + CDL treatment could increase the osteocalcin (20.85%), estradiol levels (20.61%) and decrease the TRAP activity (26.27%) significantly than CDL treatment. The combined treatment attenuated bone loss and biomechanical decrease more than single use of CDL treatment. ICA + CDL treatment significantly up-regulated the level of osteoblast-related gene expression and down-regulated the osteoclast-related genes expression; moreover, the combined treatment increased the ratio of OPG/RANKL significantly compared to ICA (72.83%) or CDL (65.63%) treatment alone. The present study demonstrates that icariin in combination with constrained dynamic loading treatment may have a therapeutic advantage over constrained dynamic loading treatment alone for the treatment of osteoporosis, which would provide new evidence for the clinical treatment of osteoporosis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1415-1424, 2018.

A role for FGF2 in visceral adiposity-associated mammary epithelial transformation

Obesity is a leading risk factor for post-menopausal breast cancer, and this is concerning as 40% of cancer diagnoses in 2014 were associated with overweight/obesity. Despite this epidemiological link, the underlying mechanism responsible is unknown. We recently published that visceral adipose tissue (VAT) releases FGF2 and stimulates the transformation of skin epithelial cells. Furthermore, obesity is differentially associated with many epithelial cancers, and this mechanistic link could be translational. As FGF2 and FGFR1 are implicated in breast cancer progression, we hypothesize that VAT-derived FGF2 plays a translational role in promoting adiposity-associated mammary epithelial cell transformation. In this brief report, data suggest that FGF2/FGFR1 signaling is a potential mechanistic link in VAT-stimulated transformation of breast epithelial cells.

Shelf Life Evaluation of Clinical Grade Chondrogenic Induced Aged Adult Stem Cells for Cartilage Regeneration

The study objectives include, enhancing the proliferations of aged bone marrow stem cells (BMSCs) and adipose stem cells (ADSCs); and evaluating the shelf lives of clinical grade chondrogenically induced cells from both samples. ADSCs and BMSCs from 56 patients (76 ± 8 yrs) were proliferated using basal medium (FD) and at (5, 10, 15, 20 and 25) ng/ml of basal fibroblast growth factor (bFGF). They were induced to chondrogenic lineage and stored for more than 120 hrs in FD, serum, Dulbecco’s phosphate buffered saline (DPBS) and saline at 4 °C. In FD, cells stagnated and BMSCs’ population doubling time (PDT) was 137 ± 30 hrs, while ADSCs’ was 129.7 ± 40 hrs. bFGF caused PDT’s decrease to 24.5 ± 5.8 hrs in BMSCs and 22.0 ± 6.5 hrs in ADSCs (p = 0.0001). Both cells were positive to stem cell markers before inductions and thereafter, expressed significantly high chondrogenic genes (p = 0.0001). On shelf life, both cells maintained viabilities and counts above 70% in FD and serum after 120 hrs. BMSCs’ viabilities in DPBS fell below 70% after 96 hrs and saline after 72 hrs. ADSCs’ viability fell below 70% in DPBS after 24 hrs and saline within 24 hrs. Concentrations between 20 ng/ml bFGF is ideal for aged adult cells’ proliferation and delivery time of induced BMSCs and ADSCs can be 120 hrs in 4 °C serum.

Elucidating the role of adipose tissue secreted factors in malignant transformation

Although there is a growing number of incidences of obesity and obesity-linked cancers, how excess adiposity actually causes cancer has not been fully explained. Our previous study showed that removal of visceral adipose tissue significantly reduced the number of ultraviolet radiation (UVR)-initiated, high-fat diet-promoted skin cancers. This commentary focuses on our recently published study (Chakraborty, et al., 2017) which demonstrated that fibroblast growth factor-2 (FGF2) released from visceral adipose tissue is a key factor in the malignant transformation of epithelial cells. Within this commentary we have provided additional interpretations and new data in support of the role of FGF2 in adiposity-associated tumorigenesis.

Fibroblast growth factor receptor is a mechanistic link between visceral adiposity and cancer

Epidemiological evidence implicates excess adipose tissue in increasing cancer risk. Despite a steeply rising global prevalence of obesity, how adiposity contributes to transformation (stage a non-tumorigenic cell undergoes to become malignant) is unknown. To determine the factors in adipose tissue that stimulate transformation, we used a novel ex vivo system of visceral adipose tissue (VAT)-condition medium-stimulated epithelial cell growth in soft agar. To extend this system in vivo, we used a murine lipectomy model of ultraviolet light B-induced, VAT-promoted skin tumor formation. We found that VAT from mice and obese human donors stimulated growth in soft agar of non-tumorigenic epithelial cells. The difference in VAT activity was associated with fibroblast growth factor-2 (FGF2) levels. Moreover, human and mouse VAT failed to stimulate growth in soft of agar in cells deficient in FGFR-1 (FGF2 receptor). We also demonstrated that circulating levels of FGF2 were associated with non-melanoma tumor formation in vivo. These data implicate FGF2 as a major factor VAT releases to transform epithelial cells-a novel, potential pathway of VAT-enhanced tumorigenesis. Strategies designed to deplete VAT stores of FGF2 or inhibit FGFR-1 in abdominally obese individuals may be important cancer prevention strategies as well as adjuvant therapies for improving outcomes.

The osteogenesis-promoting effects of alpha-lipoic acid against glucocorticoid-induced osteoporosis through the NOX4, NF-kappaB, JNK and PI3K/AKT pathways

Recently, accumulating evidence has indicated that glucocorticoid-induced osteoporosis (GIOP) is closely related to oxidative stress and apoptosis. Alpha-lipoic acid (LA), a naturally endogenous anti-oxidant, possesses anti-oxidative and anti-apoptosis activities, implicating LA as a therapeutic agent for the treatment of GIOP. In this study, the osteogenesis-promoting effects of LA against GIOP were investigated and the mechanisms were further probed. Here, the results showed that LA inhibited oxidative stress, suppressed apoptosis and improved osteopenia by promoting the expression of osteogenesis markers, including ALP, COL-I, OCN, BMP-2, RUNX2 and OSX. Further study revealed that the osteogenesis-promoting effects of LA likely occur via the regulation of the NOX4, NF-kappaB, JNK and PI3K/AKT pathways. The present study indicated that LA may prevent GIOP and promote osteogenesis and might be a candidate for the treatment of GIOP.

Growth Factors in the Pathogenesis of Retinal Neurodegeneration in Diabetes Mellitus

Neurodegeneration is an initial process in the development of diabetic retinopathy (DR).

High quantities of glutamate, oxidative stress, induction of the renin-angiotensin system (RAS) and elevated levels of RAGE are crucial elements in the retinal neurodegeneration caused by diabetes mellitus. At least, there is emerging proof to indicate that the equilibrium between the neurotoxic and neuroprotective components will affect the state of the retinal neurons.

Somatostatin (SST), pigment epithelium-derived factor (PEDF), and erythropoietin (Epo) are endogenous neuroprotective peptides that are decreased in the eye of diabetic persons and play an essential role in retinal homeostasis. On the other hand, insulin-like growth factor 1 (IGF-1), and vascular endothelial growth factor (VEGF) are pivotal proteins which participate in the development of new capillaries and finally cause damage to the retinal neurons. During recent years, our knowledge about the function of growth factors in the pathogenesis of retinal neurodegeneration has increased. However, intensive investigations are needed to clarify the basic processes that contribute to retinal neurodegeneration and its association with damage to the capillary blood vessels. The objective of this review article is to show new insights on the role of neurotransmitters and growth factors in the pathogenesis of diabetic retinopathy. The information contained in this manuscript may provide the basis for novel strategies based on the factors of neurodegeneration to diagnose, prevent and treat DR in its earliest phases.

Astragaloside I Stimulates Osteoblast Differentiation Through the Wnt/β-catenin Signaling Pathway

Astragaloside I (As-I), one of the main active ingredients in Astragalus membranaceus, is believed to have osteogenic properties, but this hypothesis has not been investigated in detail. In the present work, the As-I-induced osteogenic effects and its underlying mechanism were studied in MC3T3-E1 cells. The results indicated that the cellular levels of ALP and extracellular matrix calcium increased in a dose-dependent manner by As-I. To clarify the mechanisms involved in this process, the effect of As-I on the key osteogenic-related genes was investigated. We found that As-I stimulated the expression of β-catenin and Runx2 in MC3T3-E1 cells, which play central roles in the Wnt/β-catenin signaling pathway, suggesting that As-I could promote osteoblastic differentiation by regulating the Wnt/β-catenin signaling pathway. Moreover, the osteogenic effect of As-I could be inhibited by DKK-1, which is the classical inhibitor of Wnt/β-catenin-signaling pathway. Furthermore, As-I also increased BMP-2, BGP and OPG/RANKL expression, which are also activated by Wnt/β-catenin signaling pathway. Taken together, our findings show that As-I stimulates osteoblast differentiation through the Wnt/β-catenin signaling pathway, which also activates the BMP pathway and RANK pathway, thus highlighting the As-I for pharmaceutical and medicinal applications such as treating bone disease. Copyright © 2016 John Wiley & Sons, Ltd.

Enhancement of tendon-to-bone healing after anterior cruciate ligament reconstruction using bone marrow-derived mesenchymal stem cells genetically modified with bFGF/BMP2

Many strategies, including various growth factors and gene transfer, have been used to augment healing after anterior cruciate ligament (ACL) reconstruction. The biological environment regulated by the growth factors during the stage of tendon-bone healing was considered important in controlling the integrating process. The purpose of this study was to evaluate the effects of bone marrow-derived mesenchymal stem cells (BMSCs) genetically modified with bone morphogenetic protein 2 (BMP2) and basic fibroblast growth factor (bFGF) on healing after ACL reconstruction. BMSCs were infected with an adenoviral vector encoding BMP2 (AdBMP2) or bFGF (AdbFGF). Then, the infected BMSCs were surgically implanted into the tendon-bone interface. At 12 weeks postoperatively, the formation of abundant cartilage-like cells, smaller tibial bone tunnel and significantly higher ultimate load and stiffness levels, through histological analysis, micro-computed tomography and biomechanical testing, were observed. In addition, the AdBMP2-plus-AdbFGF group had the smallest bone tunnel and the best mechanical properties among all the groups. The addition of BMP2 or bFGF by gene transfer resulted in better cellularity, new bone formation and higher mechanical property, which contributed to the healing process after ACL reconstruction. Furthermore, the co-application of these two genes was more powerful and efficient than either single gene therapy.

Dual blockade of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2) exhibits potent anti-angiogenic effects

Both vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF or FGF-2) are potent pro-angiogenic factors and play a critical role in cancer development and progression. Clinical anti-VEGF therapy trials had a major challenge due to upregulated expression of other pro-angiogenic factor, like FGF-2. This study developed a novel chimeric decoy receptor VF-Trap fusion protein to simultaneously block activity of both VEGF and FGF pathways in order to achieve an additive or synergistic anti-tumor effect. Our in vitro data showed that VF-Trap potently blocked proliferation and migration of both VEGF- and FGF-2-induced vascular endothelial cells. In animal models, treatment of xenograft tumors with VF-Trap resulted in significant inhibition of tumor growth compared to blockage of the single molecule, like VEGF or FGF blocker. In addition, VF-Trap was also more potent in inhibition of ocular angiogenesis in a mouse oxygen-induced retinopathy (OIR) model. These data demonstrated the potent anti-angiogenic effects of this novel VF-Trap fusion protein on blockage of VEGF and FGF-2 activity in vitro and in animal models. Further study will assess its effects in clinic as a therapeutic agent for angiogenesis-related disorders, such as cancer and ocular vascular diseases.

Effects of Scytosiphon lomentaria on osteoblastic proliferation and differentiation of MC3T3-E1 cells

BACKGROUND/OBJECTIVES

Bone formation and bone resorption continuously occur in bone tissue to prevent the accumulation of old bone, this being called bone remodeling. Osteoblasts especially play a crucial role in bone formation through the differentiation and proliferation. Therefore, in this study, we investigated the effects of Scytosiphon lomentaria extract (SLE) on osteoblastic proliferation and differentiation in MC3T3-E1 cells.

MATERIALS/METHODS

A cell proliferation assay, alkaline phosphatase (ALP) activity assay, alizarin red staining and protein expression analysis of osteoblastic genes were carried out to assess the osteoblastic proliferation and differentiation.

RESULTS

The results indicated that treatment of SLE promoted the proliferation of MC3T3-E1 cells and improved ALP activity. And, SLE treatment significantly promoted mineralized nodule formation compared with control. In addition, cells treated with SLE significantly upregulated protein expression of ALP, type 1 collagen, bone morphogenetic protein 2, runt-related transcription factor 2, osterix, and osteoprotegerin.

CONCLUSIONS

The results demonstrate that SLE promote differentiation inducement and proliferation of osteoblasts and, therefore may help to elucidate the transcriptional mechanism of bone formation and possibly lead to the development of bone-forming drugs.

The Effect of Covalently Immobilized FGF-2 on Biphasic Calcium Phosphate Bone Substitute on Enhanced Biological Compatibility and Activity

The purpose of this research was to covalently graft fibroblast growth factor 2 (FGF-2) onto biphasic calcium phosphate (BCP) via a bifunctional cross-linker technique and to estimate the optimal dose of FGF-2 resulting in the best osteogenic differentiation of human mesenchymal stem cells (hMSCs). SEM observation revealed that the surface of the 100 ng FGF-2 coated BCP was completely covered with the nanoparticles expected to be from the silane coupling agent. XRD, FT-IR, and XPS analysis showed that silane treatment, bifunctional cross-linker coating, and FGF-2 covalent grafts were conducted successfully without deforming the crystalline structure of BCP. An MTT assay demonstrated that FGF-2 coated BCP had good biocompatibility, regardless of the concentration of FGF-2, after 24 or 48 h of incubation. An alkaline phosphatase (ALP) activity assay (14 days of incubation) and the ALP gene expression level of real-time PCR analysis (7 days of incubation) revealed that 50, 100, and 200 ng FGF-2 coated BCP induced the highest activities among all experimental groups and control group (P < 0.05). Thus, low concentrations of FGF-2 facilitated excellent osteogenesis and were effective at enhancing osteogenic potential. Also, the bifunctional cross-linker technique is expected to be a more feasible way to induce osteogenic differentiation while minimizing the risk of FGF-2 overdose.

Mechanisms of action of hESC-secreted proteins that enhance human and mouse myogenesis

Adult stem cells grow poorly in vitro compared to embryonic stem cells, and in vivo stem cell maintenance and proliferation by tissue niches progressively deteriorates with age. We previously reported that factors produced by human embryonic stem cells (hESCs) support a robust regenerative capacity for adult and old mouse muscle stem/progenitor cells. Here we extend these findings to human muscle progenitors and investigate underlying molecular mechanisms. Our results demonstrate that hESC-conditioned medium enhanced the proliferation of mouse and human muscle progenitors. Furthermore, hESC-produced factors activated MAPK and Notch signaling in human myogenic progenitors, and Delta/Notch-1 activation was dependent on MAPK/pERK. The Wnt, TGF-β and BMP/pSmad1,5,8 pathways were unresponsive to hESC-produced factors, but BMP signaling was dependent on intact MAPK/pERK. c-Myc, p57, and p18 were key effectors of the enhanced myogenesis promoted by the hECS factors. To define some of the active ingredients of the hESC-secretome which may have therapeutic potential, a comparative proteomic antibody array analysis was performed and identified several putative proteins, including FGF2, 6 and 19 which as ligands for MAPK signaling, were investigated in more detail. These studies emphasize that a “youthful” signaling of multiple signaling pathways is responsible for the pro-regenerative activity of the hESC factors.

Osteoprotegerin in Cardiometabolic Disorders

Osteoprotegerin (OPG), a glycoprotein traditionally implicated in bone remodelling, has been recently related to cardiovascular disease (CVD). Human studies show a positive relationship between circulating OPG, vascular damage, and CVD, and as such OPG has emerged as a potential biomarker for CVD. This review focuses on the relationship between circulating OPG and different endocrine cardiometabolic alterations such as type 1 and 2 diabetes. The association of OPG with diabetic complications (neuropathy, nephropathy, or retinopathy) as well as with atherosclerosis, coronary artery calcification, morbidity, and mortality is pointed out. Moreover, OPG modulation by different treatments is also established. Besides, other associated diseases such as obesity, hypertension, and metabolic syndrome, which are known cardiovascular risk factors, are also considered.

Autophagy regulator BECN1 suppresses mammary tumorigenesis driven by WNT1 activation and following parity

Earlier studies reported allelic deletion of the essential autophagy regulator BECN1 in breast cancers implicating BECN1 loss, and likely defective autophagy, in tumorigenesis. Recent studies have questioned the tumor suppressive role of autophagy, as autophagy-related gene (Atg) defects generally suppress tumorigenesis in well-characterized mouse tumor models. We now report that, while it delays or does not alter mammary tumorigenesis driven by Palb2 loss or ERBB2 and PyMT overexpression, monoallelic Becn1 loss promotes mammary tumor development in 2 specific contexts, namely following parity and in association with wingless-type MMTV integration site family, member 1 (WNT1) activation. Our studies demonstrate that Becn1 heterozygosity, which results in immature mammary epithelial cell expansion and aberrant TNFRSF11A/TNR11/RANK (tumor necrosis factor receptor superfamily, member 11a, NFKB activator) signaling, promotes mammary tumorigenesis in multiparous FVB/N mice and in cooperation with the progenitor cell-transforming WNT1 oncogene. Similar to our Becn1(+/-);MMTV-Wnt1 mouse model, low BECN1 expression and an activated WNT pathway gene signature correlate with the triple-negative subtype, TNFRSF11A axis activation and poor prognosis in human breast cancers. Our results suggest that BECN1 may have nonautophagy-related roles in mammary development, provide insight in the seemingly paradoxical roles of BECN1 in tumorigenesis, and constitute the basis for further studies on the pathophysiology and treatment of clinically aggressive triple negative breast cancers (TNBCs).

The importance of the prenyl group in the activities of osthole in enhancing bone formation and inhibiting bone resorption in vitro

Osteoporosis treatment always aimed at keeping the balance of bone formation and bone resorption. Recently, prenyl group in natural products has been proposed as an active group to enhance the osteogenesis process. Osthole has both the prenyl group and bone-protective activities, but the relationship is still unknown. In this study we found that osthole exerted a potent ability to promote proliferation and osteogenic function of rat bone marrow stromal cells and osteoblasts, including improved cell viability, alkaline phosphatase activity, enhanced secretion of collagen-I, bone morphogenetic protein-2, osteocalcin and osteopontin, stimulated mRNA expression of insulin-like growth factor-1, runt-related transcription factor-2, osterix, OPG (osteoprotegerin), RANKL (receptor activator for nuclear factor-κB ligand), and the ratio of OPG/RANKL, as well as increasing the formation of mineralized nodules. However, 7-methoxycoumarin had no obvious effects. Osthole also inhibited osteoclastic bone resorption to a greater extent than 7-methoxycoumarin, as shown by a lower tartrate-resistant acid phosphatase activity and lower number and smaller area of resorption pits. Our findings demonstrate that osthole could be a potential agent to stimulate bone formation and inhibit bone resorption, and the prenyl group plays an important role in these bone-protective effects.

Dioscin promotes osteoblastic proliferation and differentiation via Lrp5 and ER pathway in mouse and human osteoblast-like cell lines

Background

Dioscin, a typical steroid saponin, is isolated from Dioscorea nipponica Makino and Dioscorea zingiberensis Wright. It has estrogenic activity and many studies have also reported that dioscorea plants have an effect in preventing and treating osteoporosis. However, the molecular mechanisms underlying their effect on osteoporosis treatment are poorly understood. Therefore, the present study aims to investigate the mechanism (s) by which dioscin promotes osteoblastic proliferation and differentiation in mouse pre-osteoblast like MC3T3-E1 cells and human osteoblast-like MG-63 cells.

Results

We found that dioscin (0.25 μg/ml, 0.5 μg/ml, and 1.0 μg/ml) promoted MC3T3-E1 cells and MG-63 cells proliferation and differentiation dose dependently. Western blot analysis results showed that estrogen receptor α (ER-α), estrogen receptor β (ER-β), β-catenin and Bcl-2 protein expression increased after MC3T3-E1 cells were treated with dioscin. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that dioscin could increase the ratio of osteoprotegerin (OPG)/receptor activator of NF-κB ligand (RANKL) and up-regulate the level of Lrp5 and β-catenin. And by RNA interference analysis, we proved that the effect of dioscin increasing the ratio of OPG/RANKL was dependent on Lrp5 pathway. In addition, we also found that these effects of dioscin were abolished by ICI 182, 780 (100 nM), an antagonist of ER, indicating that an ER signaling pathway was also involved. We also found that dioscin (0.25 μg/ml, 0.5 μg/ml, and 1.0 μg/ml) induced MG-63 cells proliferation and differentiation in a dose-dependent manner. Western blot analysis results indicated that ER-α, ER-β and β-catenin protein expression increased after MG-63 cells were treated with dioscin.

Conclusions

The current study is the first to reveal that dioscin can promote osteoblasts proliferation and differentiation via Lrp5 and ER pathway.

The angiogenic peptide vascular endothelial growth factor-basic fibroblast growth factor signaling is up-regulated in a rat pressure ulcer model

The purpose of this study is to investigate the mRNA and protein expression levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in pressure ulcers, and to elucidate the molecular mechanism by which VEGF and bFGF are involved in pressure ulcer formation. A rat model of ischemia-reperfusion pressure ulcer was established by magnetic disk circulating compression method. Real-time fluorescence quantitative PCR and Western blot assays were conducted to detect the mRNA and protein expression of VEGF and bFGF in the tissues of rat I-, II-, and III-degree pressure ulcers, the surrounding tissues, and normal skin. Our study confirmed that the mRNA and protein expression levels of VEGF and bFGF in the tissues of rat I-degree pressure ulcer were significantly higher than that in the II- and III-degree pressure ulcer tissues (P < 0.05). The expression of VEGF and bFGF in the tissues surrounding I- and II-degree pressure ulcers were higher than the rats with normal skin. The expression of VEGF and bFGF in the tissues of rat III-degree pressure ulcer was lower than that in the surrounding tissues and normal skin (P < 0.05). There was a significant positive correlation between change in the VEGF and bFGF. The results showed that with an increase in the degree of pressure ulcers, the expression of VEGF and bFGF in pressure ulcers tissue are decreased. This leads to a reduction in angiogenesis and may be a crucial factor in the formation of pressure ulcers.

Rare massive osteolipoma in the upper part of the knee in a young adult

Lipoma is a common benign soft tissue tumor. This article describes a massive osteolipoma, an unusual lipoma that is fixed to the femoral periosteum. A 21-year-old man presented with a subcutaneous mass at the knee region, which had been present for more than 36 months, and a slight limitation of joint flexibility. On physical examination, a mass approximately 12×6×2 cm(3) in dimension was palpable beneath the skin at the knee proximal medial area when the knee was in flexion. The mass was ovoid, hard, nontender, well demarcated, large, subcutaneous, and relatively fixed to the femur. Medical imaging examination showed that the femur had a well-demarcated mass with a basement. No prominent body weight loss was noted. The excisional mass of 16×12×10 cm(3) was not well encapsulated by a thin, fibrous membrane and had an apparently osseous basal portion. Intraoperative rapid frozen section revealed that the tumor was derived from the adipose cells. The postoperative course was uneventful. The definitive pathologic diagnosis was intermuscular osteolipoma without evidence of malignancy. No recurrence was observed at 6-month follow-up. Osteolipoma with independent bone and an osseous basal portion is rare, especially in young adults. Osteolipoma has the same prognosis as simple lipoma, and surgical excision is the recommended treatment. To the authors' knowledge, such a massive osteolipoma has not been reported.

Intercellular cross-talk among bone cells: new factors and pathways

Intercellular communication within the bone microenvironment is critical for the maintenance of normal bone structure. Osteoblast-lineage cells at all stages of differentiation, from pluripotent precursors to matrix-embedded osteocytes, produce regulatory factors that modulate the differentiation and activity of both bone-forming osteoblasts and bone-resorbing osteoclasts. Osteoclasts can also release factors that feed back to regulate osteoblast activity. Intercellular cross-talk within the bone microenvironment is not restricted only to these bone cells. Other cells within the bone marrow microenvironment, including adipocytes, T cells, and macrophages, play key roles that influence the processes of bone formation and resorption. This review discusses recent work that provides new insights into some of these communication networks and the factors involved, including osteocytic production of receptor activator of nuclear factor-κB ligand (RANKL) and sclerostin, osteoblastic production of interleukin-33, osteoclast-derived Semaphorin 4D, ephrin signaling, and signals from T helper cells and resident osteal macrophages (osteomacs).