Sirt1 Promotes Osteogenic Differentiation and Increases Alveolar Bone Mass via Bmi1 Activation in Mice

Melatonin Reverses the Loss of Stemness Induced by TNF-α in Human Bone Marrow Mesenchymal Stem Cells through Upregulation of YAP Expression

Mesenchymal stem cells (MSCs) are promising candidates for tissue regeneration and disease treatment. However, long-term in vitro culture results in loss of MSC stemness. The inflammation that occurs at stem cell transplant sites (such as that resulting from TNF-α) is a contributing factor for stem cell treatment failure. Currently, there is little evidence regarding the protective role of melatonin with regard to the negative effects of TNF-α on the stemness of MSCs. In this study, we report a melatonin-based method to reduce the inflammatory effects on the stemness of bone marrow mesenchymal stem cells (BMMSCs). The results of colony formation assays, Alizarin red staining, western blotting, and reverse transcription-polymerase chain reactions suggest that melatonin can reverse the inflammatory damage caused by TNF-α treatment in the third, seventh, and tenth generations of primary BMMSCs (vs. control and the TNF-α-treated group). Meanwhile, a detailed analysis of the molecular mechanisms showed that the melatonin receptor and YAP signaling pathway are closely related to the role that melatonin plays in negative inflammatory effects against BMMSCs. In addition, in vivo experiments showed that melatonin could reverse the damage caused by TNF-α on bone regeneration by BMMSCs in nude mice. Overall, our results suggest that melatonin can reverse the loss of stemness caused by inflammatory factor TNF-α in BMMSCs. Our results also provide a practical strategy for the application of BMMSCs in tissue engineering and cell therapy.

Epigenetic regulation of bone remodeling by natural compounds

Osteoporosis and osteopenia impact more than 54 million Americans, resulting in significant morbidity and mortality. Alterations in bone remodeling are the hallmarks for osteoporosis, and thus the development of novel treatments that will prevent or treat bone diseases would be clinically significant, and improve the quality of life for these patients. Bone remodeling involves the removal of old bone by osteoclasts and the formation of new bone by osteoblasts. This process is tightly coupled, and is essential for the maintenance of bone strength and integrity. Since the osteoclast is the only cell capable of bone resorption, the development of drugs to treat bone disorders has primarily focused on reducing osteoclast differentiation, maturation, and bone resorption mechanisms, and there are few treatments that actually increase bone formation. Evidence from observational, experimental, and clinical studies demonstrate a positive link between naturally occurring compounds and improved indices of bone health. While many natural extracts and compounds are reported to have beneficial effects on bone, only resveratrol, sulforaphane, specific phenolic acids and anthocyanins, have been shown to both increase bone formation and reduce resorption through their effects on the bone epigenome. Each of these compounds alters specific aspects of the bone epigenome to improve osteoblast differentiation, reduce osteoblast apoptosis, improve bone mineralization, and reduce osteoclast differentiation and function. This review focuses on these specific natural compounds and their epigenetic regulation of bone remodeling.

MiR-29a function as tumor suppressor in cervical cancer by targeting SIRT1 and predict patient prognosis

INTRODUCTION

Cervical cancer is the second most frequently malignant tumors in females and metastasis is a challenge of the treatment of cervical cancer. MiR-29a is usually low expressed in several tumors and its functions in cervical cancer remain unclear.

PATIENTS AND METHODS

The quantitative real-time polymerase chain reaction was employed to assess the expression of miR-29a and the Sirtuin-1 (SIRT1). Cell metastatic ability was assessed using Transwell and Western blot assays. The dual-luciferase reporter assay was performed to verify that miR-29a targeted to the 3'-untranslated region (UTR) of SIRT1 mRNA.

RESULTS

MiR-29a was low expressed in cervical cancer and downregulation of miR-29a was associated with poor outcome. MiR-29a regulated the expression of SIRT1 by targeting to its 3'-UTR of mRNA in HeLa cells. SIRT1 was upregulated in cervical cancer tissues and cells in comparison with the non-tumor tissues and normal cells. Upregulation of SIRT1 predicted worse outcome of cervical cancer patients. MiR-29a was participated in the migration, invasion and epithelial-mesenchymal transition (EMT) in cervical cancer through directly targeting to the 3'-UTR of SIRT1 mRNA. SIRT1 reversed partial roles of miR-29a on metastasis in cervical cancer.

CONCLUSION

miR-29a suppressed migration, invasion and EMT by directly targeting to SIRT1 in cervical cancer. The newly identified miR-29a/SIRT1 axis provides novel insight into the pathogenesis of cervical cancer.

Characteristics, Biological Properties and Analytical Methods of Trans-Resveratrol: A Review

Trans-resveratrol (TR) is the biological active isomer of resveratrol and the one responsible for therapeutic effects; both molecules are non-flavonoid phenolics of the stilbenes class found mainly in berries and red grapes. TR biological properties lie in modulation of various enzymatic classes. It is a promising candidate to novel drugs due its applications in pharmaceutical and cosmetic industries, such as anticarcinogenic, antidiabetic, antiacne, antioxidant, anti-inflammatory, neuroprotective, and photoprotector agent. It has effects on bone metabolism, gastrointestinal tract, eyes, kidneys, and in obesity treatment as well. Nevertheless, its low solubility in water and other polar solvents may be a hindrance to its therapeutic effects. Various strategies been developed to overcome these issues, such as the drug delivery systems. The present study performed a research about methods to identify TR and RESV in several samples (raw materials, wines, food supplements, drug delivery systems, and blood plasma). Most of the studies tend to analyze TR and RESV by high performance liquid chromatography (HPLC) coupled with different detectors, even so, there are reports of the use of capillary electrophoresis, electron spin resonance, gas chromatography, near-infrared luminescence, UV-Vis spectrophotometer, and vibrational spectrophotometry, for this purpose. Thus, the review evaluates the biological activity of TR and demonstrates the currently used analytical methods for its quantification in different matrices.

Bergenin Activates SIRT1 as a Novel Therapeutic Agent for Osteogenesis of Bone Mesenchymal Stem Cells

Bone mesenchymal stem cells (BMSCs) are important candidates for bone regeneration. The role of Bergenin, a C-glucoside of 4-O-methyl gallic acid obtained from the species, Bergenia, in BMSC osteogenesis has not yet been elucidated. We therefore investigated the effects of Bergenin on the osteogenesis of BMSCs and found that Bergenin enhanced osteoblast-specific markers and downregulated the adipocyte-specific markers in vitro. Furthermore, using a rat calvarial defect model, we found that Bergenin significantly improved bone healing, as determined by imaging and histological analyses. Moreover, it also upregulated SIRT1 expression. A SIRT1 inhibitor (EX 527) decreased the enhanced bone mineral formation caused by Bergenin. Taken together, these findings show that Bergenin accelerated the osteogenic differentiation of BMSCs, at least partly through the activation of SIRT1.

The role of sirtuin 1 and its activator, resveratrol in osteoarthritis

Osteoarthitis (OA) is the most common aging-related joint pathology; the aging process results in changes to joint tissues that ultimately contribute to the development of OA. Articular chondrocytes exhibit an aging-related decline in their proliferative and synthetic capacity. Sirtuin 1 (SIRT 1), a longevity gene related to many diseases associated with aging, is a nicotinamide adenine dinucleotide (NAD⁺)-dependent protein deacetylase and master metabolic regulator. Along with its natural activator resveratrol, SIRT 1 actively participates in the OA pathological progress. SIRT 1 expression in osteoarthritic cartilage decreases in the disease progression of OA; it appears to play a predominantly regulatory role in OA. SIRT 1 can regulate the expression of extracellular matrix (ECM)-related proteins; promote mesenchymal stem cell differentiation; play anti-catabolic, anti-inflammatory, anti-oxidative stress, and anti-apoptosis roles; participate in the autophagic process; and regulate bone homeostasis in OA. Resveratrol can activate SIRT 1 in order to inhibit OA disease progression. In the future, activating SIRT 1 via resveratrol with improved bioavailability may be an appropriate therapeutic approach for OA.