Cold exposure-induced plasma exosomes impair bone mass by inhibiting autophagy.

Recently, environmental temperature has been shown to regulate bone homeostasis. However, the mechanisms by which cold exposure affects bone mass remain unclear. In our present study, we observed that exposure to cold temperature (CT) decreased bone mass and quality in mice. Furthermore, a transplant of exosomes derived from the plasma of mice exposed to cold temperature (CT-EXO) can also impair the osteogenic differentiation of BMSCs and decrease bone mass by inhibiting autophagic activity. Rapamycin, a potent inducer of autophagy, can reverse cold exposure or CT-EXO-induced bone loss. Microarray sequencing revealed that cold exposure increases the miR-25-3p level in CT-EXO. Mechanistic studies showed that miR-25-3p can inhibit the osteogenic differentiation and autophagic activity of BMSCs. It is shown that inhibition of exosomes release or downregulation of miR-25-3p level can suppress CT-induced bone loss. This study identifies that CT-EXO mediates CT-induced osteoporotic effects through miR-25-3p by inhibiting autophagy via targeting SATB2, presenting a novel mechanism underlying the effect of cold temperature on bone mass.

Young osteocyte-derived extracellular vesicles facilitate osteogenesis by transferring tropomyosin-1.

BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) can undergo inadequate osteogenesis or excessive adipogenesis as they age due to changes in the bone microenvironment, ultimately resulting in decreased bone density and elevated risk of fractures in senile osteoporosis. This study aims to investigate the effects of osteocyte senescence on the bone microenvironment and its influence on BMSCs during aging. RESULTS: Primary osteocytes were isolated from 2-month-old and 16-month-old mice to obtain young osteocyte-derived extracellular vesicles (YO-EVs) and senescent osteocyte-derived EVs (SO-EVs), respectively. YO-EVs were found to significantly increase alkaline phosphatase activity, mineralization deposition, and the expression of osteogenesis-related genes in BMSCs, while SO-EVs promoted BMSC adipogenesis. Neither YO-EVs nor SO-EVs exerted an effect on the osteoclastogenesis of primary macrophages/monocytes. Our constructed transgenic mice, designed to trace osteocyte-derived EV distribution, revealed abundant osteocyte-derived EVs embedded in the bone matrix. Moreover, mature osteoclasts were found to release osteocyte-derived EVs from bone slices, playing a pivotal role in regulating the functions of the surrounding culture medium. Following intravenous injection into young and elderly mouse models, YO-EVs demonstrated a significant enhancement of bone mass and biomechanical strength compared to SO-EVs. Immunostaining of bone sections revealed that YO-EV treatment augmented the number of osteoblasts on the bone surface, while SO-EV treatment promoted adipocyte formation in the bone marrow. Proteomics analysis of YO-EVs and SO-EVs showed that tropomyosin-1 (TPM1) was enriched in YO-EVs, which increased the matrix stiffness of BMSCs, consequently promoting osteogenesis. Specifically, the siRNA-mediated depletion of Tpm1 eliminated pro-osteogenic activity of YO-EVs both in vitro and in vivo. CONCLUSIONS: Our findings suggested that YO-EVs played a crucial role in maintaining the balance between bone resorption and formation, and their pro-osteogenic activity declining with aging. Therefore, YO-EVs and the delivered TPM1 hold potential as therapeutic targets for senile osteoporosis.

Association of osteoporotic fractures of femoral neck and femoral neck geometric parameters in native Chinese women.

BACKGROUND: Although it is generally believed that the femoral neck fracture is related to the femoral neck geometric parameters (FNGPs), the association between the risk of osteoporotic fracture of the femoral neck and FNGPs in native Chinese women is still unclear. METHODS: A total of 374 female patients (mean age 70.2 ± 9.32 years) with osteoporotic fracture of the femoral neck, and 374 non-fracture control groups were completely matched with the case group according to the age ratio of 1:1. Using DXA bone densitometer to measured eight FNGPs: the outer diameter (OD), cross-sectional area (CSA), cortical thickness (CT), endocortical diameter (ED), buckling ratio (BR), section modulus (SM), cross-sectional moment of inertia (CSMI), and compressive strength index (CSI) at the narrowest point of the femoral neck. RESULTS: Compared with the control group, the average values of OD (2.9%), ED (4.5%), and BR (26.1%) in the patient group significantly increased (p = 0.015 to < 0.001), while CSA (‒15.3%), CT (‒18.2%), SM (‒10.3%), CSMI (‒6.4%), and CSI (‒10.8%) significantly decreased (all p < 0.001). The prevalence of osteoporosis in the lumbar spine, femoral neck, and total hip was, respectively, 82%, 81%, and 65% in fracture patients. Cox proportional hazard model analysis showed that in the age adjusted model, the fracture hazard ratio (HR) of CSA, CT, BR, SM, and CSI significantly increased (HRs = 1.60‒8.33; 95% CI = 1.08‒16.6; all p < 0.001). In the model adjusted for age and femoral neck BMD, HRs of CT (HRs = 3.90‒8.03; 95% CI = 2.45‒15.1; all p < 0.001) and BR (HRs = 1.62‒2.60; 95% CI = 1.20‒5.44; all p < 0.001) were still significantly increased. CONCLUSION: These results suggest that the majority of osteoporotic fractures of the femoral neck of native Chinese women occur in patients with osteoporosis. CT thinning or BR increase of FNGPs may be independent predictors of fragility fracture of femoral neck in native Chinese women unrelated to BMD.

Vascular wall microenvironment: exosomes secreted by adventitial fibroblasts induced vascular calcification.

Vascular calcification often occurs in patients with chronic renal failure (CRF), which significantly increases the incidence of cardiovascular events in CRF patients. Our previous studies identified the crosstalk between the endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), and the paracrine effect of VSMCs, which regulate the calcification of VSMCs. Herein, we aim to investigate the effects of exosomes secreted by high phosphorus (HPi) -induced adventitial fibroblasts (AFs) on the calcification of VSMCs and the underlying mechanism, which will further elucidate the important role of AFs in high phosphorus vascular wall microenvironment. The conditioned medium of HPi-induced AFs promotes the calcification of VSMCs, which is partially abrogated by GW4869, a blocker of exosomes biogenesis or release. Exosomes secreted by high phosphorus-induced AFs (AFsHPi-Exos) show similar effects on VSMCs. miR-21-5p is enriched in AFsHPi-Exos, and miR-21-5p enhances osteoblast-like differentiation of VSMCs by downregulating cysteine-rich motor neuron 1 (Crim1) expression. AFsHPi-Exos and exosomes secreted by AFs with overexpression of miR-21-5p (AFsmiR21M-Exos) significantly accelerate vascular calcification in CRF mice. In general, AFsHPi-Exos promote the calcification of VSMCs and vascular calcification by delivering miR-21-5p to VSMCs and subsequently inhibiting the expression of Crim1. Combined with our previous studies, the present experiment supports the theory of vascular wall microenvironment.

Cold exposure protects against medial arterial calcification development via autophagy.

Medial arterial calcification (MAC), a systemic vascular disease different from atherosclerosis, is associated with an increased incidence of cardiovascular events. Several studies have demonstrated that ambient temperature is one of the most important factors affecting cardiovascular events. However, there has been limited research on the effect of different ambient temperatures on MAC. In the present study, we showed that cold temperature exposure (CT) in mice slowed down the formation of vitamin D (VD)-induced vascular calcification compared with room temperature exposure (RT). To investigate the mechanism involved, we isolated plasma-derived exosomes from mice subjected to CT or RT for 30 days (CT-Exo or RT-Exo, respectively). Compared with RT-Exo, CT-Exo remarkably alleviated the calcification/senescence formation of vascular smooth muscle cells (VSMCs) and promoted autophagy by activating the phosphorylation of AMP-activated protein kinase (p-AMPK) and inhibiting phosphorylation of mammalian target of rapamycin (p-mTOR). At the same time, CT-Exo promoted autophagy in ß-glycerophosphate (ß-GP)-induced VSMCs. The number of autophagosomes and the expression of autophagy-related proteins ATG5 and LC3B increased, while the expression of p62 decreased. Based on a microRNA chip microarray assay and real-time polymerase chain reaction, miR-320a-3p was highly enriched in CT-Exo as well as thoracic aortic vessels in CT mice. miR-320a-3p downregulation in CT-Exo using AntagomiR-320a-3p inhibited autophagy and blunted its anti-calcification protective effect on VSMCs. Moreover, we identified that programmed cell death 4 (PDCD4) is a target of miR-320a-3p, and silencing PDCD4 increased autophagy and decreased calcification in VSMCs. Treatment with CT-Exo alleviated the formation of MAC in VD-treated mice, while these effects were partially reversed by GW4869. Furthermore, the anti-arterial calcification protective effects of CT-Exo were largely abolished by AntagomiR-320a-3p in VD-induced mice. In summary, we have highlighted that prolonged cold may be a good way to reduce the incidence of MAC. Specifically, miR-320a-3p from CT-Exo could protect against the initiation and progression of MAC via the AMPK/mTOR autophagy pathway.

Association of follicle-stimulating hormone with bone turnover markers and bone mineral density in Chinese women across the menopausal transition.

BACKGROUND: Elevated follicle-stimulating hormone (FSH) is associated with an increased risk of postmenopausal osteoporosis. This study investigated the association of serum FSH with bone turnover markers (BTMs) and bone mineral density (BMD) in healthy women undergoing menopausal transition. METHODS: A total of 487 healthy women (age 35-65 years, 50 ± 8.5 years) were enrolled in this study. Serum FSH, BTMs, and BMD at lumbar spine and total hip were measured in these subjects. RESULTS: Follicle-stimulating hormone was positively correlated with various BTMs (r = 0.339-0.583, all p < 0.001) and negatively correlated with lumbar spine and total hip BMD (r = -0.629 and -0.514, all p < 0.001). After adjusting for age and body mass index, the partial correlation coefficients of FSH with BTMs and BMD remained significant. Estimating from the regression equation, for every 10 IU/L increase in serum FSH, BTMs increased by 0.38-3.6 units, and BMD decreased by 0.03-0.05 g/cm2 , respectively. Multiple linear regression analysis showed that FSH was a positive factor for serum bone-specific alkaline phosphatase, osteocalcin, and N-telopeptide of collagen type 1 (ß = 0.188-0.403, all p < 0.001), and a negative factor for lumbar spine BMD and serum C-telopeptide of collagen type 1 (ß = -0.629 and -0.183, all p < 0.001). CONCLUSIONS: This study suggests that serum FSH levels are an independent risk factor for BTMs and BMD in menopause-transitioning women, particularly for serum BAP and lumbar spine BMD.

Protective role of small extracellular vesicles derived from HUVECs treated with AGEs in diabetic vascular calcification.

The pathogenesis of vascular calcification in diabetic patients remains elusive. As an effective information transmitter, small extracellular vesicles (sEVs) carry abundant microRNAs (miRNAs) that regulate the physiological and pathological states of recipient cells. In the present study, significant up-regulation of miR-126-5p was observed in sEVs isolated from human umbilical vein endothelial cells (HUVECs) stimulated with advanced glycation end-products (A-EC/sEVs). Intriguingly, these sEVs suppressed the osteogenic differentiation of vascular smooth muscle cells (VSMCs) by targeting BMPR1B, which encodes the receptor for BMP, thereby blocking the smad1/5/9 signalling pathway. In addition, knocking down miR-126-5p in HUVECs significantly diminished the anti-calcification effect of A-EC/sEVs in a mouse model of type 2 diabetes. Overall, miR-126-5p is highly enriched in sEVs derived from AGEs stimulated HUVECs and can target BMPR1B to negatively regulate the trans-differentiation of VSMCs both in vitro and in vivo.

[Consensus and controversy on research progress and clinical practice of vascular calcification].

Vascular calcification is an active and complex pathological process regulated by several factors. Vascular calcification is closely related to the incidence and mortality of the cardiovascular disease, chronic kidney disease and other diseases, which affects multiple organs and systems, thus affecting people's health. Therefore, more and more attention is paid to vascular calcification. At present, the pathogenesis and clinical practice of vascular calcification have been continuously improved, which mainly includes calcium and phosphorus imbalance theory, vascular smooth muscle cell transdifferentiation theory, bone homeostasis imbalance theory, epigenetic regulation theory, inflammation theory, extracellular matrix theory, new cell fate theory and so on. However, there are still many unsolved problems. Since the occurrence and development of vascular calcification affect multiple organs and systems, this expert consensus gathered clinicians and basic research experts engaged in the study of vascular calcification in order to summarize the progress of various disciplines related to vascular calcification in recent years. The purpose of this consensus is to systematically summarize the latest research progress, treatment consensus and controversy of vascular calcification from the aspects of epidemiology, pathogenesis, prevention and treatment, so as to provide theoretical basis and clinical enlightenment for in-depth research in this field.

Relationship between bone mineral density and fragility fracture risk: a case-control study in Changsha, China.

BACKGROUND: Fragility fracture is associated with bone mineral density (BMD), and most databases used in related researches are instrument-matched. Little is known about the relationship between BMD and fragility fracture risk of native Chinese, especially using local databases as reference databases. OBJECTIVE: To investigate relationship between BMD and risk of fragility fracture in native China. METHODS: 3,324 cases, including 2,423 women (67.7 ± 8.9 years) and 901 men (68.4 ± 11.6 years) having radiological fragility fractures and 3,324 age- and gender-matched controls participated in the study. We measured BMD at posteroanterior spine and hip using dual-energy X-ray absorptiometry (DXA), calculated BMD measurement parameters based on our own BMD reference database. RESULTS: BMDs and mean T-scores were lower in case group (with clinical fragility) than in control group (without clinical fragility). In patients with fragility fractures, prevalence of lumbar osteoporosis, low bone mass, and normal BMD were 78.9 %, 19.3 %, and 1.8 %, respectively, in women, and 49.5, 44.8 %, and 5.7 %, respectively, in men. In hip, these prevalence rates were 67.2 %, 28.4 %, and 4.4 % in females, and 43.2 %, 45.9 %, and 10.9 % in males, respectively, showing differences between females and males. Multivariate Cox regression analysis showed that after adjusting age, height, weight, and body mass index, fracture hazard ratio (HR) increased by 2.7-2.8 times (95 % CI 2.5-3.1) and 3.6-4.1 times (95 %CI 3.0-5.1) for women and men respectively with decreasing BMD parameters. In both sexes, risk of fragility fracture increased approximately 1.6-1.7 times (95 % CI 1.5-1.8) for every 1 T-score reduction in BMD. CONCLUSIONS: Risk of clinical fragility fracture increases with decreasing BMD measurement parameters and anthropometric indicators in native China, and fracture HR varies from gender and site.

Melatonin alleviates vascular calcification and ageing through exosomal miR-204/miR-211 cluster in a paracrine manner.

In the elderly with atherosclerosis, hypertension and diabetes, vascular calcification and ageing are ubiquitous. Melatonin (MT) has been demonstrated to impact the cardiovascular system. In this study, we have shown that MT alleviates vascular calcification and ageing, and the underlying mechanism involved. We found that both osteogenic differentiation and senescence of vascular smooth muscle cells (VSMCs) were attenuated by MT in a MT membrane receptor-dependent manner. Moreover, exosomes isolated from VSMCs or calcifying vascular smooth muscle cells (CVSMCs) treated with MT could be uptaken by VSMCs and attenuated the osteogenic differentiation and senescence of VSMCs or CVSMCs, respectively. Moreover, we used conditional medium from MT-treated VSMCs and Transwell assay to confirm exosomes secreted by MT-treated VSMCs attenuated the osteogenic differentiation and senescence of VSMCs through paracrine mechanism. We also found exosomal miR-204/miR-211 mediated the paracrine effect of exosomes secreted by VSMCs. A potential target of these two miRs was revealed to be BMP2. Furthermore, treatment of MT alleviated vascular calcification and ageing in 5/6-nephrectomy plus high-phosphate diet-treated (5/6 NTP) mice, while these effects were partially reversed by GW4869. Exosomes derived from MT-treated VSMCs were internalised into mouse artery detected by in vivo fluorescence image, and these exosomes reduced vascular calcification and ageing of 5/6 NTP mice, but both effects were largely abolished by inhibition of exosomal miR-204 or miR-211. In summary, our present study revealed that exosomes from MT-treated VSMCs could attenuate vascular calcification and ageing in a paracrine manner through an exosomal miR-204/miR-211.

Age-related bone turnover markers and osteoporotic risk in native Chinese women.

BACKGROUND: The rate of bone turnover is closely related to osteoporosis risk. We investigated the correlation between bone turnover markers and BMD at various skeletal sites in healthy native Chinese women, and to study the effect of changes in the levels of bone turnover markers on the risk of osteoporosis. METHODS: A cross-section study of 891 healthy Chinese women aged 20-80 years was conducted. The levels of serum osteocalcin (OC), bone-specific alkaline phosphatase (BAP), serum cross-linked N-terminal telopeptides of type I collagen (sNTX), cross-linked C-terminal telopeptides of type I collagen (sCTX), urinary NTX (uNTX), urinary CTX (uCTX) and total urinary deoxypyridinoline (uDPD) were determined. BMD at the posteroanterior spine and the hip was measured using DXA. RESULTS: Pearson's correlation coefficient found significant negative correlation between bone turnover marker and BMD T-score at different skeletal sites (r = -0.08 to -0.52, all P = 0.038-0.000). After adjustments for age and body mass index, the partial correlation coefficients between the OC, BAP, sNTX, sCTX and uCTX, and the T-scores at various skeletal sites were still significant. After adjustment of height and weight, the correlation coefficients between most BTMs and PA lumbar spine BMD were also significant. Multiple linear regression analysis showed that bone turnover markers were negative determinants of T-scores. BAP and OC accounted for 33.1% and 7.8% of the variations in the T-scores of the PA spine, respectively. Serum OC, BAP, uDPD, and sNTX accounted for 0.4-21.9% of the variations in the femoral neck and total hip T-scores. The bone turnover marker levels were grouped as per quartile intervals, and the T-scores, osteoporosis prevalence and risk were found to markedly and increase with increase in bone turnover marker levels. CONCLUSIONS: This study clarified the relationship between bone turnover markers and osteoporosis risk in native Chinese women. Bone turnover marker levels were found to be important determinants of BMD T-scores. Furthermore, osteoporotic risk significantly increased with increase in the levels of bone turnover markers.

Adipose exosomal noncoding RNAs: Roles and mechanisms in metabolic diseases.

Exosomes are extracellular vesicles, measuring 40-160 nm in diameter, that are released by many cell types and tissues, including adipose tissue. Exosomes are critical mediators of intercellular communication and their contents are complex and diverse. In recent years, accumulating evidence has proved that multiple adipose tissue-derived exosomal noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), play pivotal roles in the pathogenesis of diverse metabolic diseases, such as obesity. In this narrative review, we focus on the adipose tissue-derived exosomal ncRNAs, especially exosomal miRNAs, and their dysregulation in multiple types of metabolic diseases. A deeper understanding of the role of adipose tissue-derived exosomal ncRNAs may help provide new diagnostic and treatment methods for metabolic diseases.

Assessment of causal association between the socio-economic status and osteoporosis and fractures: a bidirectional Mendelian randomization study in European population.

BACKGROUND: The relationship between socio-economic status and bone-related diseases is attracting increasing attention. Therefore, a bidirectional Mendelian randomization (MR) analysis was performed in this study. METHODS: Genetic data on factors associated with socio-economic status (average total household income before tax, years of schooling completed and Townsend Deprivation Index at recruitment), femoral neck bone mineral density (FN-BMD), heel bone mineral density (eBMD), osteoporosis, and five different sites of fracture (spine, femur, lower leg-ankle, foot, and wrist-hand fractures) were derived from genome-wide association summary statistics of European ancestry. The inverse variance weighted method was employed to obtain the causal estimates, complemented by alternative MR techniques, including MR-Egger, weighted median, and MR-pleiotropy residual sum and outlier (MR-PRESSO). Furthermore, sensitivity analyses, and multivariable MR was performed to enhance the robustness of our findings. RESULTS: A higher educational attainment was associated with an increased level of eBMD (beta:0.06, 95% CI:0.01-0.10, P = 7.24 × 10-3), and decreased risk of osteoporosis (OR:0.78, 95% CI:0.65-0.94, P = 8.49 × 10-3), spine fracture (OR:0.76, 95% CI:0.66-0.88, P = 2.94 × 10-4), femur fracture (OR:0.78, 95% CI:0.67-0.91, P = 1.33 × 10-3), lower leg-ankle fracture (OR:0.79, 95% CI:0.70-0.88, P = 2.05 × 10-5), foot fracture (OR:0.78, 95% CI:0.66-0.93, P = 5.92 × 10-3) and wrist-hand fracture (OR:0.83, 95% CI:0.73-0.95, P = 7.15 × 10-3). Further, material deprivation seemed to harm the spine fracture (OR:2.63, 95% CI:1.43-4.85, P = 1.91 × 10-3). A higher level of FN-BMD positively affected increased household income (beta:0.03, 95% CI:0.01-0.04, P = 6.78 × 10-3). All these estimates were adjusted for body mass index (BMI), type 2 diabetes, smoking initiation, and frequency of alcohol intake. CONCLUSIONS: The Mendelian randomization analyses show that higher educational levels is associated with higher eBMD, reduced risk of osteoporosis and fractures, while material deprivation is positively related to spine fracture. Enhanced FN-BMD correlates with increased household income. These findings offer valuable insights into the formulation of health guidelines and policy development.

We conducted stratified analyses to explore the causal links between socio-economic status and osteoporosis and various fractures and observed that education significantly reduced risk of osteoporosis and lower eBMD. It also lowered the risks of fractures of spine, femur, lower leg-ankle, foot, and wrist-hand, while material deprivation exhibited positive associations with spine fracture risk. Bidirectional MR analysis showed that an elevated score of FN-BMD was associated with a higher income level. Our study shows the importance of conducting routine BMD estimations and osteoporosis screening, to enhance knowledge and awareness among individuals to promote bone health and prevent fractures.

Ghrelin inhibits the apoptosis of MC3T3-E1 cells through ERK and AKT signaling pathway.

Ghrelin is a 28-amino-acid peptide that acts as a natural endogenous ligand of the growth hormone secretagogue receptor (GHSR) and strongly stimulates the release of growth hormone from the hypothalamus-pituitary axis. Previous studies have identified the important physiological effects of ghrelin on bone metabolism, such as regulating proliferation and differentiation of osteoblasts, independent of GH/IGF-1 axis. However, research on effects and mechanisms of ghrelin on osteoblast apoptosis is still rare. In this study, we identified expression of GHSR in MC3T3-E1 cells and determined the effects of ghrelin on the apoptosis of osteoblastic MC3T3-E1 cells and the mechanism involved. Our data demonstrated that ghrelin inhibited the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, as determined by terminal deoxynucleotidyl transferase-mediated deoxyribonucleotide triphosphate nick end-labeling (TUNEL) and ELISA assays. Moreover, ghrelin upregulated Bcl-2 expression and downregulated Bax expression in a dose-dependent manner. Our study also showed decreased activated caspase-3 activity under the treatment of ghrelin. Further study suggested that ghrelin stimulated the phosphorylation of ERK and AKT. Pretreatment of cells with the ERK inhibitor PD98059, PI3K inhibitor LY294002, and GHSR-siRNA blocked the ghrelin-induced activation of ERK and AKT, respectively; however, ghrelin did not stimulate the phosphorylation of p38 or JNK. PD90859, LY294002 and GHSR-siRNA attenuated the anti-apoptosis effect of ghrelin in MC3T3-E1 cells. In conclusion, ghrelin inhibits the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, which may be mediated by activating the GHSR/ERK and GHSR/PI3K/AKT signaling pathways.

Vaspin attenuates the apoptosis of human osteoblasts through ERK signaling pathway.

It has been hypothesized that adipocytokines originating from adipose tissue may have an important role in bone metabolism. Vaspin is a novel adipocytokine isolated from visceral white adipose tissue, which has been reported to have anti-apoptotic effects in vascular endothelial cells. However, to the best of our knowledge there is no information regarding the effects of vaspin on osteoblast apoptosis. This study therefore examined the possible effects of vaspin on apoptosis in human osteoblasts (hOBs). Our study established that vaspin inhibits hOBs apoptosis induced by serum deprivation, as determined by ELISA and TUNEL assays. Western blot analysis revealed that vaspin upregulates the expression of Bcl-2 and downregulates that of Bax in a dose-dependent manner. Vaspin stimulated the phosphorylation of ERK, and pretreatment of hOBs with the ERK inhibitor PD98059 blocked the vaspin-induced activation of ERK, however, vaspin did not stimulate the phosphorylation of p38, JNK or Akt. Vaspin protects hOBs from serum deprivation-induced apoptosis, which may be mediated by activating the MAPK/ERK signaling pathway.

Epigenetic regulation in metabolic diseases: mechanisms and advances in clinical study.

Epigenetics regulates gene expression and has been confirmed to play a critical role in a variety of metabolic diseases, such as diabetes, obesity, non-alcoholic fatty liver disease (NAFLD), osteoporosis, gout, hyperthyroidism, hypothyroidism and others. The term 'epigenetics' was firstly proposed in 1942 and with the development of technologies, the exploration of epigenetics has made great progresses. There are four main epigenetic mechanisms, including DNA methylation, histone modification, chromatin remodelling, and noncoding RNA (ncRNA), which exert different effects on metabolic diseases. Genetic and non-genetic factors, including ageing, diet, and exercise, interact with epigenetics and jointly affect the formation of a phenotype. Understanding epigenetics could be applied to diagnosing and treating metabolic diseases in the clinic, including epigenetic biomarkers, epigenetic drugs, and epigenetic editing. In this review, we introduce the brief history of epigenetics as well as the milestone events since the proposal of the term 'epigenetics'. Moreover, we summarise the research methods of epigenetics and introduce four main general mechanisms of epigenetic modulation. Furthermore, we summarise epigenetic mechanisms in metabolic diseases and introduce the interaction between epigenetics and genetic or non-genetic factors. Finally, we introduce the clinical trials and applications of epigenetics in metabolic diseases.

Global publication trends and research trends of necroptosis application in tumor: A bibliometric analysis.

Introduction: Necroptosis is an alternative, caspase-independent programmed cell death that appears when apoptosis is inhibited. A gowing number of studies have reflected the link between necroptosis and tumors. However, only some systematical bibliometric analyses were focused on this field. In this study, we aimed to identify and visualize the cooperation between countries, institutions, authors, and journals through a bibliometric analysis to help understand the hotspot trends and emerging topics regarding necroptosis and cancer research. Methods: The articles and reviews on necroptosis and cancer were obtained from the Web of Science Core Collection on 16 September 2022. Countries, institutions, authors, references, and keywords in this field were visually analyzed by CtieSpace 5.8.R3, VOSviewer 1.6.18, and R package "bibliometrix." Results: From 2006 to 2022, 2,216 qualified original articles and reviews on necroptosis in tumors were published in 685 academic journals by 13,009 authors in 789 institutions from 75 countries/regions. Publications focusing on necroptosis and cancer have increased violently in the past 16 years, while the citation number peaked around 2008-2011. Most publications were from China, while the United States maintained the dominant position as a "knowledge bridge" in necroptosis and cancer research; meanwhile, Ghent University and the Chinese Academy of Sciences were the most productive institutions. Moreover, only a tiny portion of the articles were multiple-country publications. Peter Vandenabeele had the most significant publications, while Alexei Degterev was most often co-cited. Peter Vandenabeele also gets the highest h-index and g-index in this research field. Cell Death and Disease was the journal with the most publications on necroptosis and cancer, which was confirmed to be the top core source by Bradford's Law. At the same time, Cell was the leading co-cited journal, and the focus area of these papers was molecular, biology, and immunology. High-frequency keywords mainly contained those that are molecularly related (MLKL, NF-kB, TNF, RIPK3, RIPK1), pathological process related (necroptosis, apoptosis, cell-death, necrosis, autophagy), and mechanism related (activation, expression, mechanisms, and inhibition). Conclusion: This study comprehensively overviews necroptosis and cancer research using bibliometric and visual methods. Research related to necroptosis and cancer is flourishing. Cooperation and communication between countries and institutions must be further strengthened. The information in our paper would provide valuable references for scholars focusing on necroptosis and cancer.

Taurine suppresses osteoblastic differentiation of aortic valve interstitial cells induced by beta-glycerophosphate disodium, dexamethasone and ascorbic acid via the ERK pathway.

Aortic valve calcification (AVC) is an active process characterized by osteoblastic differentiation of the aortic valve interstitial cells (AVICs). Taurine is a free ß-amino acid and plays important physiological roles including protective effect of cardiovascular events. To evaluate the possible role of taurine in AVC, we isolated human AVICs from patients with type A dissection without leaflet disease. We demonstrated that the cultured AVICs express SM α-actin, vimentin and taurine transporter (TAUT), but not CD31, SM-myosin or desmin. We also established the osteoblastic differentiation model of the AVICs induced by pro-calcific medium (PCM) containing ß-glycerophosphate disodium, dexamethasone and ascorbic acid in vitro. The results showed that taurine attenuated the PCM-induced osteoblastic differentiation of AVICs by decreasing the alkaline phosphate (ALP) activity/expression and the expression of the core binding factor α1 (Cbfα1) in a dose-dependent manner (reaching the maximum protective effect at 10 mM), and taurine (10 mM) inhibited the mineralization level of AVICs in the form of calcium content significantly. Furthermore, taurine activated the extracellular signal-regulated protein kinase (ERK) pathway via TAUT, and the inhibitor of ERK (PD98059) abolished the effect of taurine on both ALP activity/expression and Cbfα1 expression. These results suggested that taurine could inhibit osteoblastic differentiation of AVIC via the ERK pathway.