During evolution, the development of bone was critical for many species to thrive and function in the boundary conditions of Earth. Furthermore, bone also became a storehouse for calcium that could be mobilized for reproductive purposes in mammals and other species. The critical nature of bone for both function and reproductive needs during evolution in the context of the boundary conditions of Earth has led to complex regulatory mechanisms that require integration for optimization of this tissue across the lifespan. Three important regulatory variables include mechanical loading, sex hormones, and innervation/neuroregulation. The importance of mechanical loading has been the target of much research as bone appears to subscribe to the \"use it or lose it\" paradigm. Furthermore, because of the importance of post-menopausal osteoporosis in the risk for fractures and loss of function, this aspect of bone regulation has also focused research on sex differences in bone regulation. The advent of space flight and exposure to microgravity has also led to renewed interest in this unique environment, which could not have been anticipated by evolution, to expose new insights into bone regulation. Finally, a body of evidence has also emerged indicating that the neuroregulation of bone is also central to maintaining function. However, there is still more that is needed to understand regarding how such variables are integrated across the lifespan to maintain function, particularly in a species that walks upright. This review will attempt to discuss these regulatory elements for bone integrity and propose how further study is needed to delineate the details to better understand how to improve treatments for those at risk for loss of bone integrity, such as in the post-menopausal state or during prolonged space flight.

As the global population ages, bone-related diseases have increasingly become a major social problem threatening human health. Exosomes, as natural cell products, have been used to treat bone-related diseases due to their superior biocompatibility, biological barrier penetration, and therapeutic effects. Moreover, the modified exosomes exhibit strong bone-targeting capabilities that may improve efficacy and avoid systemic side effects, demonstrating promising translational potential. However, a review of bone-targeted exosomes is still lacking. Thus, the recently developed exosomes for bone-targeting applications in this review are focused. The biogenesis and bone-targeting regulatory functions of exosomes, the constructive strategies of modified exosomes to improve bone-targeting, and their therapeutic effects for bone-related diseases are introduced. By summarizing developments and challenges in bone-targeted exosomes, It is striven to shed light on the selection of exosome constructive strategies for different bone diseases and highlight their translational potential for future clinical orthopedics.

Sirtuins are a family of nicotinamide adenine dinucleotide (NAD)+-dependent histone deacetylases, comprising seven members SIRT1-SIRT7. Sirtuins have been extensively studied in regulating ageing and age-related diseases. Sirtuins are also pivotal modulators in oxidative stress and inflammation, as they can regulate the expression and activation of downstream transcriptional factors (such as Forkhead box protein O3 (FOXO3a), nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-kappa B (NF-κB)) as well as antioxidant enzymes, through epigenetic modification and post-translational modification. Most importantly, studies have shown that aberrant sirtuins are involved in the pathogenesis of infectious and inflammatory oral diseases, and oral cancer. In this review, we provide a comprehensive overview of the regulatory patterns of sirtuins at multiple levels, and the essential roles of sirtuins in regulating inflammation, oxidative stress, and bone metabolism. We summarize the involvement of sirtuins in several oral diseases such as periodontitis, apical periodontitis, pulpitis, oral candidiasis, oral herpesvirus infections, dental fluorosis, and oral cancer. At last, we discuss the potential utilization of sirtuins as therapeutic targets in oral diseases.

The heterogeneity of \"rare bone disorders\" can be explained by the number of molecules and regulatory pathways which are responsible for bone health and normal stature. In this article, the most important basic principles behind bone homeostasis from development to structure and regulation of the growing skeleton are summarized. The aim is to provide the reader with some theoretical background to understand the nature of the different main groups of disorders affecting bone stability, longitudinal growth and disturbances of calcium and phosphate homeostasis.
UNASSIGNED: Hinter der Gruppe seltener Knochenerkrankungen steht ursächlich eine Vielzahl unterschiedlicher Regulationsmechanismen, welche auch die Heterogenität der verschiedenen Erkrankungsbilder erklärt. In diesem Artikel soll ein Überblick über grundsätzliche Aspekte der Entwicklung, der Struktur und der Regulation des wachsenden Skelettsystems gegeben werden. Auf diese Weise sollen dem interessierten Leser die ganz unterschiedlichen seltenen Ursachen hinter erhöhter Frakturneigung, aber auch seltenen Wachstumsstörungen und Störungen der Mineralisation verständlich präsentiert werden.

Traditional Chinese medicine has been proven to be effective in treating human diseases according to a long-term observation for more than 2000 years. However, the precise molecular mechanisms of a majority of the medications are still largely unknown. Deer antler has been clinically used as an effective animal medication in traditional Chinese medicine for many centuries. Previous studies have demonstrated that antler extracts play crucial roles in promoting bone and cartilage development, growth and repair. However, the underlying molecular mechanism remains to be elucidated. In the present study, we applied isobaric tags for relative and absolute quantitation (iTRAQ) technology and a systematic bioinformatics analysis accompanied with validation method to obtain a full spectrum of the serum protein profiles under deer antler extract treatment. We identified a complex interaction network formed by the positive regulation of Tropomyosins (Tpm1, 2 and 4), WD repeat-containing protein 1 (Wdr1), Alpha-actinin-1 (Actn1) and Destrin (Dstn) and the negative regulation of Alpha-2-macroglobulin (A2m), Serine protease inhibitor A3 N (Serpina3n) and Apolipoproteins (Apoh and Apof), which coordinately interact with multiple proteins and signaling pathways. Our results suggest that the therapeutic effects of deer antler extract on treating bone diseases might achieved though the regulation of bone formation and remodeling by controlling a series of serum proteins and signaling pathways that were essential for osteoblast and osteoclast activities. Thus, this study has greatly deepened the current knowledge about the molecular mechanism of therapeutic effects of deer antler extract on bone diseases such as osteoporosis.