Neuropeptide Y upregulates Runx2 and osterix and enhances osteogenesis in mouse MC3T3‑E1 cells via an autocrine mechanism

The significance of neural electrophysiological and functional effects of cervical spinal ganglia and sympathetic ganglia in cervical vertigo

This study investigates the neural electrophysiological and functional effects of cervical spinal ganglia and sympathetic ganglia in cervical vertigo. Twenty-eight rabbits were randomized into superior cervical sympathetic ganglia (SCSG) group (n = 8), inferior cervical sympathetic ganglia (ICSG) group (n = 8) and control groups for both SCSG and ICSG (n = 6 each). Calcium indicator CaMPARI2 was injected into the ganglia. Four weeks later, both SCSG and ICSG groups underwent electrical stimulation followed by UV irradiation. Control groups did not receive electrical stimulation but were also injected with the calcium indicator and irradiated by UV. Additionally, 63 rabbits were randomized into three groups: cervical spinal ganglia stimulation (n = 21), paravertebral nerve blockage (n = 21), and simultaneous blockage of paravertebral nerve and cervical spinal ganglia (n = 21), all subjected to the same electrical stimulation protocol. Results indicated that calcium concentration in the cervical sympathetic ganglia after stimulation was significantly higher compared to the control group (P < 0.05). Blood flow changes in both vertebral artery and basilar artery were significant after electrical stimulation (P < 0.05). In the paravertebral nerve blockage group, significant changes in basilar artery blood flow were observed (P < 0.05), while no significant blood flow changes were noted in the simultaneous blockage group. Cervical spinal ganglia and sympathetic ganglia in the pathogenesis of cervical vertigoThese findings underscore the importance of neural electrophysiological and functional effects of cervical spinal ganglia and sympathetic ganglia in the pathogenesis of cervical vertigo.

Harmine promotes odontoblastic differentiation of dental pulp stem cells

INTRODUCTION

Dental pulp stem cells (DPSCs) have the potential to differentiate into various types of tissues including tooth, adipose, cartilage, muscle, nerve, and also possess regenerative properties. Harmine, a beta-carboline alkaloid, has been shown to have antitumor activities and promote bone formation through the differentiation of osteoblasts. The aim of this study was to investigate the effect of harmine on the differentiation of DPSCs into odontoblast cells.

MATERIALS AND METHODS

DPSCs were obtained from Iran's National Genetic Reserve Center and cultured under standard stem cell culture conditions. The cells were differentiated in culture medium with and without harmine, and cell viability was evaluated using MTT assay at different harmine concentrations. Moreover, differentiation of cells was measured using Alizarin Red staining, and the expression of Runx2, DSPP, and DMP1 genes was evaluated using western blotting and real-time PCR.

RESULTS

Harmine increased the survival rate of DPSCs in a time--dependent manner, but higher doses (above 80 μM) had a toxic effect. On day 14, Alizarin Red staining showed increased differentiation of odontoblasts in the harmine-treated groups compared to the untreated groups. Furthermore, harmine increased the expression of Runx2, DSPP, and DMP1 genes and proteins.

CONCLUSION

These findings suggest that harmine has a significant impact on the differentiation and proliferation of odontoblasts in DPSCs, likely due to its various properties and role in healing various diseases. Therefore, harmine could serve as a potential therapeutic agent for promoting dental tissue regeneration using DPSCs.

The role and mechanism of β-catenin-mediated skeletal muscle satellite cells in osteoporotic fractures by Jian-Pi-Bu-Shen formula

Osteoporosis is a metabolic bone disease. β-Catenin is associated with fractures. Jian-Pi-Bu-Shen (JPBS) can promote the healing of osteoporotic fractures (OPF). However, the mechanism of β-catenin-mediated skeletal muscle satellite cells (SMSCs) in OPF by the JPBS is unclear. SMSCs were isolated and divided into five groups. The results showed that the survival rate of SMSCs was significantly higher in the low, medium, and high dose JPBS-containing serum groups after 7 days of incubation. The ALP activity and the number of SMSCs mineralized in the JPBS-containing serum intervention group were elevated. Axin, GSK-3β, β-catenin siRNAs were constructed and transfected into cells. Transfection of siRNAs reduced Axin, GSK-3β, and β-catenin expressions, respectively. β-Catenin-siRNA reversed ALP activity, the number of SMSCs mineralized, and the expression of β-catenin, BMP2, Runx2, COL-I, SP7/Ostrix, Osteocalcin, and BMP-7. Transcriptomic results suggested that the TNF signaling pathway associated with OPF was enriched. SD rats were subjected to the construction of OPF model by removing the ovaries. JPBS decreased the levels of PINP, ALP, CTX, and NTX through β-catenin in OPF rats, while increasing Runx2, β-catenin expressions through β-catenin at the broken end of fractures. Moreover, JPBS decreased BMC, BMD, and BV/TV and improved pathological damage through β-catenin in OPF rats. JPBS decreased the expression of Axin, GSK-3β mRNA, and protein, but increased the expressions of β-catenin, Pax7, COL-II, COL-II, BMP2, and Runx2 through β-catenin in OPF rats. In conclusion, JPBS inhibits Axin/GSK-3β expression, activates the β-catenin signaling, and promotes the osteogenic differentiation of SMSCs.

S100 calcium‑binding protein A16 suppresses the osteogenic differentiation of rat bone marrow mesenchymal stem cells by inhibiting SMAD family member 4 signaling

Osteogenesis is a complex process of bone formation regulated by various factors, yet its underlying molecular mechanisms remain incompletely understood. The present study aimed to investigate the role of S100A16, a novel member of the S100 protein family, in the osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs) and uncover a novel Smad4-mitogen-activated protein kinase (MAPK)/Jun N-terminal kinase (JNK) signaling axis. In the present study, the expression level of S100A16 in bone tissues and BMSCs from ovariectomized rats was evaluated and then the impact of S100A16 silencing on osteogenic differentiation was examined. Increased S100A16 expression was observed in bone tissues and BMSCs from ovariectomized rats, and S100A16 silencing promoted osteogenic differentiation. Further transcriptomic sequencing revealed that the Smad4 pathway was involved in S100A16 silencing-induced osteogenesis. The results of western blot analysis revealed that S100A16 overexpression not only downregulated Smad4 but also activated MAPK/JNK signaling, which was validated by treatment with MAPK and JNK inhibitors U0126 and SP600125. Overall, in the present study, the novel regulatory factors influencing osteogenic differentiation were elucidated and mechanistic insights that could aid in the development of targeted therapeutic strategies for patients with osteoporosis were provided.

Interaction between the nervous and skeletal systems

The skeleton is one of the largest organ systems in the body and is richly innervated by the network of nerves. Peripheral nerves in the skeleton include sensory and sympathetic nerves. Crosstalk between bones and nerves is a hot topic of current research, yet it is not well understood. In this review, we will explore the role of nerves in bone repair and remodeling, as well as summarize the molecular mechanisms by which neurotransmitters regulate osteogenic differentiation. Furthermore, we discuss the skeleton’s role as an endocrine organ that regulates the innervation and function of nerves by secreting bone-derived factors. An understanding of the interactions between nerves and bone can help to prevent and treat bone diseases caused by abnormal innervation or nerve function, develop new strategies for clinical bone regeneration, and improve patient outcomes.

The Role of NPY in the Regulation of Bone Metabolism

Bone diseases are the leading causes of disability and severely compromised quality of life. Neuropeptide Y (NPY) is a multifunctional neuropeptide that participates in various physiological and pathological processes and exists in both the nerve system and bone tissue. In bone tissue, it actively participates in bone metabolism and disease progression through its receptors. Previous studies have focused on the opposite effects of NPY on bone formation and resorption through paracrine modes. In this review, we present a brief overview of the progress made in this research field in recent times in order to provide reference for further understanding the regulatory mechanism of bone physiology and pathological metabolism.

Recent Advances of Osterix Transcription Factor in Osteoblast Differentiation and Bone Formation

With increasing life expectations, more and more patients suffer from fractures either induced by intensive sports or other bone-related diseases. The balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption is the basis for maintaining bone health. Osterix (Osx) has long been known to be an essential transcription factor for the osteoblast differentiation and bone mineralization. Emerging evidence suggests that Osx not only plays an important role in intramembranous bone formation, but also affects endochondral ossification by participating in the terminal cartilage differentiation. Given its essentiality in skeletal development and bone formation, Osx has become a new research hotspot in recent years. In this review, we focus on the progress of Osx's function and its regulation in osteoblast differentiation and bone mass. And the potential role of Osx in developing new therapeutic strategies for osteolytic diseases was discussed.