PIP5k1β controls bone homeostasis through modulating both osteoclast and osteoblast differentiation

Regulatory mechanisms of autophagy-related ncRNAs in bone metabolic diseases

Bone metabolic diseases have been tormented and are plaguing people worldwide due to the lack of effective and thorough medical interventions and the poor understanding of their pathogenesis. Non-coding RNAs (ncRNAs) are heterogeneous transcripts that cannot encode the proteins but can affect the expressions of other genes. Autophagy is a fundamental mechanism for keeping cell viability, recycling cellular contents through the lysosomal pathway, and maintaining the homeostasis of the intracellular environment. There is growing evidence that ncRNAs, autophagy, and crosstalk between ncRNAs and autophagy play complex roles in progression of metabolic bone disease. This review investigated the complex mechanisms by which ncRNAs, mainly micro RNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), regulate autophagic pathway to assist in treating bone metabolism disorders. It aimed at identifying the autophagy role in bone metabolism disorders and understanding the role, potential, and challenges of crosstalk between ncRNAs and autophagy for bone metabolism disorders treatment.

Fucoidan (Undaria pinnatifida)/Polydopamine Composite-Modified Surface Promotes Osteogenic Potential of Periodontal Ligament Stem Cells

Fucoidan, a marine-sulfated polysaccharide derived from brown algae, has been recently spotlighted as a natural biomaterial for use in bone formation and regeneration. Current research explores the osteoinductive and osteoconductive properties of fucoidan-based composites for bone tissue engineering applications. The utility of fucoidan in a bone tissue regeneration environment necessitates a better understanding of how fucoidan regulates osteogenic processes at the molecular level. Therefore, this study designed a fucoidan and polydopamine (PDA) composite-based film for use in a culture platform for periodontal ligament stem cells (PDLSCs) and explored the prominent molecular pathways induced during osteogenic differentiation of PDLSCs through transcriptome profiling. Characterization of the fucoidan/PDA-coated culture polystyrene surface was assessed by scanning electron microscopy and X-ray photoelectron spectroscopy. The osteogenic differentiation of the PDLSCs cultured on the fucoidan/PDA composite was examined through alkaline phosphatase activity, intracellular calcium levels, matrix mineralization assay, and analysis of the mRNA and protein expression of osteogenic markers. RNA sequencing was performed to identify significantly enriched and associated molecular networks. The culture of PDLSCs on the fucoidan/PDA composite demonstrated higher osteogenic potency than that on the control surface. Differentially expressed genes (DEGs) (n = 348) were identified during fucoidan/PDA-induced osteogenic differentiation by RNA sequencing. The signaling pathways enriched in the DEGs include regulation of the actin cytoskeleton and Ras-related protein 1 and phosphatidylinositol signaling. These pathways represent cell adhesion and cytoskeleton organization functions that are significantly involved in the osteogenic process. These results suggest that a fucoidan/PDA composite promotes the osteogenic potential of PDLSCs by activation of critical molecular pathways.

Polycyclic aromatic hydrocarbons in bone homeostasis

Prolonged exposure to polycyclic aromatic hydrocarbons (PAHs) may result in autoimmune diseases, such as rheumatoid arthritis (RA) and osteoporosis (OP), which are based on an imbalance in bone homeostasis. These diseases are characterized by bone erosion and even a disruption in homeostasis, including in osteoblasts and osteoclasts. Current evidence indicates that multiple factors affect the progression of bone homeostasis, such as genetic susceptibility and epigenetic modifications. However, environmental factors, especially PAHs from various sources, have been shown to play an increasingly prominent role in the progression of bone homeostasis. Hence, it is essential to investigate the effects and pathogenesis of PAHs in bone homeostasis. In this review, recent progress is summarized concerning the effects and mechanisms of PAHs and their ligands and receptors in bone homeostasis. Moreover, strategies based on the effects and mechanisms of PAHs in the regulation of the bone balance and alleviation of bone destruction are also reviewed. We further discuss the future challenges and perspectives regarding the roles of PAHs in autoimmune diseases based on bone homeostasis.

lncRNA SNHG1 induced by SP1 regulates bone remodeling and angiogenesis via sponging miR-181c-5p and modulating SFRP1/Wnt signaling pathway

BACKGROUND

We aimed to investigate the functions and underlying mechanism of lncRNA SNHG1 in bone differentiation and angiogenesis in the development of osteoporosis.

METHODS

The differential gene or proteins expressions were measured by qPCR or western blot assays, respectively. The targeted relationships among molecular were confirmed through luciferase reporter, RIP and ChIP assays, respectively. Alkaline phosphatase (ALP), alizarin red S (ARS) and TRAP staining were performed to measure the osteoblast/osteoclast differentiation of BMSCs. The viability, migration and angiogenesis in BM-EPCs were validated by CCK-8, clone formation, transwell and tube formation assays, respectively. Western blot and immunofluorescence detected the cytosolic/nuclear localization of β-catenin. Ovariectomized (OVX) mice were established to confirm the findings in vitro.

RESULTS

SNHG1 was enhanced and miR-181c-5p was decreased in serum and femoral tissue from OVX mice. SNHG1 directly inhibited miR-181c-5p to activate Wnt3a/β-catenin signaling by upregulating SFRP1. In addition, knockdown of SNHG1 promoted the osteogenic differentiation of BMSCs by increasing miR-181c-5p. In contrast, SNHG1 overexpression advanced the osteoclast differentiation of BMSCs and inhibited the angiogenesis of BM-EPCs, whereas these effects were all reversed by miR-181c-5p overexpression. In vivo experiments indicated that SNHG1 silencing alleviated osteoporosis through stimulating osteoblastogenesis and inhibiting osteoclastogenesis by modulating miR-181c-5p. Importantly, SNHG1 could be induced by SP1 in BMSCs.

CONCLUSIONS

Collectively, SP1-induced SNHG1 modulated SFRP1/Wnt/β-catenin signaling pathway via sponging miR-181c-5p, thereby inhibiting osteoblast differentiation and angiogenesis while promoting osteoclast formation. Further, SNHG1 silence might provide a potential treatment for osteoporosis.

The use of glutathione to reduce oxidative stress status and its potential for modifying the extracellular matrix organization in cleft lip

OBJECTIVE

Cleft lip (CL) is a common congenital anomaly that can be syndromic or non-syndromic. It can be triggered by the mutation of gene or environmental factors. The incidence of CL is about 1 out of 700 live births. Facial development is a complex process, and there is no existing therapy to prevent the disease development. One of the characteristics in this facial malformation is the increased presence of reactive oxygen species (ROS). In this study, we hypothesize that the antioxidant glutathione (GSH) could help to attenuate the oxidative stress in this disease.

METHODS

Bioinformatics network pharmacology was applied to determine pharmacological targets and molecular mechanisms of GSH treatment for CL. Moreover, RNA-sequencing of the POLR1C knockdown osteoblast CL model was applied to validate the in silico data of using GSH in CL.

RESULTS

Twenty-two core targets of GSH and CL were identified via various bioinformatics tools. The GO and KEGG analysis indicated that GSH could modulate two major families (matrix metalloproteinase and integrins), which are related to extracellular matrix modification and composition for facial development in CL. The findings from POLR1C knockdown model further supported the rescue response of GSH in CL.

CONCLUSIONS

The study uncovered the possible pharmacological mechanism of GSH for treating CL. The data helps research group to focus on the specific pathways for understanding the biological action of GSH for treating the CL in the future.

Macrophages Switch to an Osteo-Modulatory Profile Upon RANKL Induction in a Medaka (Oryzias latipes) Osteoporosis Model

In mammals, osteoclasts differentiate from macrophages in the monocyte lineage. Although many factors driving osteoclast formation are known, the detailed processes underlying precursor recruitment, differentiation, and interaction of macrophages with other cell types involved in bone remodeling are poorly understood. Using live imaging in a transgenic medaka osteoporosis model, where ectopic osteoclasts are induced by RANKL expression, we show that a subset of macrophages is recruited to bone matrix to physically interact with bone-forming osteoblast progenitors. These macrophages subsequently differentiate into cathepsin K- (ctsk-) positive osteoclasts. One day later, other macrophages are recruited to clear dying osteoclasts from resorbed bone by phagocytosis. To better understand the molecular changes underlying these dynamic processes, we performed transcriptome profiling of activated macrophages upon RANKL induction. This revealed an upregulation of several bone-related transcripts. Besides osteoclast markers, we unexpectedly also found expression of osteoblast-promoting signals in activated macrophages, suggesting a possible non-cell autonomous role in osteogenesis. Finally, we show that macrophage differentiation into osteoclasts is dependent on inflammatory signals. Medaka deficient for TNFα or treated with the TNFα-inhibitor pentoxifylline exhibited impaired macrophage recruitment and osteoclast differentiation. These results show the involvement of inflammatory signals and the dynamics of a distinct subset of macrophages during osteoclast formation. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.