Osteopontin is involved in urotensin II-induced migration of rat aortic adventitial fibroblasts

Recent studies suggest that both osteopontin and urotensin II (UII) play critical roles in vascular remodeling. We previously showed that UII could stimulate the migration of aortic adventitial fibroblasts. In this study, we examined whether osteopontin is involved in UII-induced migration of rat aortic adventitial fibroblasts and examined the effects and mechanisms of UII on osteopontin expression in adventitial fibroblasts. Migration of adventitial fibroblasts induced by UII could be inhibited significantly by osteopontin antisense oligonucleotide (P < 0.01) but not sense or mismatch oligonucleotides (P > 0.05). Moreover, UII dose- and time-dependently promoted osteopontin mRNA expression and protein secretion in the cells, with maximal effect at 10⁻⁸ mol/l at 3 h for mRNA expression or at 12 h for protein secretion (both P < 0.01). Furthermore, the UII effects were significantly inhibited by its receptor antagonist SB710411 (10⁻⁶ mol/l), and Ca²⁺ channel blocker nicardipine (10⁻⁵ mol/l), protein kinase C (PKC) inhibitor H7 (10⁻⁵ mol/l), calcineurin inhibitor cyclosporine A (10⁻⁵ mol/l), mitogen-activated protein kinase (MAPK) inhibitor PD98059 (10⁻⁵ mol/l) and Rho kinase inhibitor Y-27632 (10⁻⁵ mol/l). Thus, osteopontin is involved in the UII-induced migration of adventitial fibroblasts, and UII could upregulate osteopontin gene expression and protein synthesis in rat aortic adventitial fibroblasts by activating its receptor and the Ca²⁺ channel, PKC, calcineurin, MAPK and Rho kinase signal transduction pathways.     

Novel bioactivity of phosvitin in connective tissue and bone organogenesis revealed by live calvarial bone organ culture models

Egg yolk phosvitin is one of the most highly phosphorylated extracellular matrix proteins known in nature with unique physico-chemical properties deemed to be critical during ex-vivo egg embryo development. We have utilized our unique live mouse calvarial bone organ culture models under conditions which dissociates the two bone remodeling stages, viz., resorption by osteoclasts and formation by osteoblasts, to highlight important and to date unknown critical biological functions of egg phosvitin. In our resorption model live bone cultures were grown in the absence of ascorbate and were stimulated by parathyroid hormone (PTH) to undergo rapid osteoclast formation/differentiation with bone resorption. In this resorption model native phosvitin potently inhibited PTH-induced osteoclastic bone resorption with simultaneous new osteoid/bone formation in the absence of ascorbate (vitamin C). These surprising and critical observations were extended using the bone formation model in the absence of ascorbate and in the presence of phosvitin which supported the above results. The results were corroborated by analyses for calcium release or uptake, tartrate-resistant acid phosphatase activity (marker for osteoclasts), alkaline phosphatase activity (marker for osteoblasts), collagen and hydroxyproline composition, and histological and quantitative histomorphometric evaluations. The data revealed that the discovered bioactivity of phosvitin mirrors that of ascorbate during collagen synthesis and the formation of new osteoid/bone. Complementing those studies use of the synthetic collagen peptide analog and cultured calvarial osteoblasts in conjunction with mass spectrometric analysis provided results that augmented the bone organ culture work and confirmed the capacity of phosvitin to stimulate differentiation of osteoblasts, collagen synthesis, hydroxyproline formation, and biomineralization. There are striking implications and interrelationships of this affect that relates to the evolutionary inactivation of the gene of an enzyme l-gulono-γ-lactone oxidase, which is involved in the final step of ascorbate biosynthesis, in many vertebrate species including passeriform birds, reptiles and teleost fish whose egg yolk contain phosvitin. These represent examples of how developing ex-vivo embryos of such species can achieve connective tissue and skeletal system formation in the absence of ascorbate.     

Protein related to DAN and cerberus (PRDC) inhibits osteoblastic differentiation and its suppression promotes osteogenesis in vitro

Protein related to DAN and cerberus (PRDC) is a secreted protein characterized by a cysteine knot structure, which binds bone morphogenetic proteins (BMPs) and thereby inhibits their binding to BMP receptors. As an extracellular BMP antagonist, PRDC may play critical roles in osteogenesis; however, its expression and function in osteoblastic differentiation have not been determined. Here, we investigated whether PRDC is expressed in osteoblasts and whether it regulates osteogenesis in vitro. PRDC mRNA was found to be expressed in the pre-osteoblasts of embryonic day 18.5 (E18.5) mouse calvariae. PRDC mRNA expression was elevated by treatment with BMP-2 in osteoblastic cells isolated from E18.5 calvariae (pOB cells). Forced expression of PRDC using adenovirus did not affect cell numbers, whereas it suppressed exogenous BMP activity and endogenous levels of phosphorylated Smad1/5/8 protein. Furthermore, PRDC inhibited the expression of bone marker genes and bone-like mineralized matrix deposition in pOB cells. In contrast, the reduction of PRDC expression by siRNA elevated alkaline phosphatase activity, increased endogenous levels of phosphorylated Smad1/5/8 protein, and promoted bone-like mineralized matrix deposition in pOB cells. These results suggest that PRDC expression in osteoblasts suppresses differentiation and that reduction of PRDC expression promotes osteogenesis in vitro. PRDC is accordingly identified as a potential novel therapeutic target for the regulation of bone formation.     

红藤养胃汤对胃癌患者血清MG7-Ag、TPS及OPN水平的影响

目的:探讨红藤养胃汤治疗胃癌的疗效及对血清胃癌相关抗原(MG7-Ag)、骨桥蛋白(OPN)、组织多肽特异性抗原(TPS)水平的影响。方法:选择2015年2月至2017年1月在我院进行胃癌治疗的86例患者,将其随机均分为观察组和对照组,每组43例。对照组患者给予奥美拉唑治疗,观察组患者在对照组基础上给予红藤养胃汤疗,比较两组患者的临床疗效,治疗前后血清MG7-Ag、TPS、OPN水平变化及不良反应的发生情况。结果:治疗后,观察组总有效率显著高于对照组,血清MG7-Ag、TPS、OPN水平均显著低于对照组,差异均具有统计学意义(P0.05),且恶心呕吐、发热及白细胞减少等不良反应的发生率显著低于对照组(P0.05)。结论:红藤养胃汤可显著提高胃癌患者的临床疗效,减少不良反应,有效降低患者血清MG7-Ag、TPS、OPN水平。     

慢性鼻窦炎伴鼻息肉患者血清OPN、BAFF、25-（OH）D3的变化及对息肉组织分型的鉴别价值探讨

摘要 目的：探讨慢性鼻窦炎伴鼻息肉（CRSwNP）患者血清骨桥蛋白（OPN）、B细胞活化因子（BAFF）、25羟基维生素D3[25-（OH）D3]水平及其对息肉组织分型的鉴别价值。方法：选取2019年6月-2021年6月于延安大学附属医院治疗的87例CRSwNP患者为CRSwNP组,根据息肉组织嗜酸粒细胞浸润程度将其分为嗜酸性CRSwNP患者（ECRSwNP组,n=41）和非嗜酸性CRSwNP患者（nECRSwNP组,n=46）。选取同期于延安大学附属医院治疗的慢性鼻窦炎不伴鼻息肉患者（CRSsNP组,n=60）和健康体检者（对照组,n=60）。比较CRSwNP组、CRSsNP组和对照组患者血清OPN、BAFF、25-（OH）D3水平。采用多因素Logistic回归分析ECRSwNP发生的影响因素,采用受试者工作特征（ROC）曲线评估各指标对CRSwNP息肉组织分型的鉴别价值。结果：CRSwNP组、CRSsNP组血清OPN、BAFF水平高于对照组,25-（OH）D3水平低于对照组,且CRSwNP组血清OPN、BAFF水平高于CRSsNP组,25-（OH）D3水平低于CRSsNP组（P<0.05）。ECRSwNP组变应性鼻炎史、哮喘病史患者占比、外周血嗜酸粒细胞数量及比例、血清总IgE浓度、血清OPN及BAFF水平高于nECRSwNP组（P<0.05）,而血清25-（OH）D3水平低于nECRSwNP组（P<0.05）。多因素Logistic回归分析显示：外周血嗜酸粒细胞数量及比例、血清总IgE浓度、血清OPN及BAFF水平升高是ECRSwNP发生的危险因素（P<0.05）,25-（OH）D3水平升高是ECRSwNP的保护因素（P<0.05）。血清OPN、BAFF、25-（OH）D3对CRSwNP息肉组织分型单独检测的ROC曲线下面积（AUC）分别为：0.789、0.800、0.817,联合检测鉴别CRSwNP患者息肉组织分型的AUC为0.900,灵敏度、特异度分别为0.860、0.827,联合检测鉴别价值更高（P＜0.05）。结论：血清OPN、BAFF和25-（OH）D3水平在不同息肉组织分型中具有差异性,CRSwNP患者血清OPN和BAFF水平升高是ECRSwNP发生的危险因素,25-（OH）D3水平升高是保护因素,联合检测辅助临床鉴别CRSwNP息肉组织类型的价值更高。     

Fibroblast growth factor 21 ameliorates vascular calcification by inhibiting osteogenic transition in vitamin D3 plus nicotine-treated rats

FGF21, a special member of FGF superfamily, has been proven to have pleiotropic metabolic effects and many potential therapeutic action in various metabolic disorders. Vascular calcification (VC), a perplexing clinical issue, is a major risk factor for many cardiovascular diseases, especially for patients with some metabolic diseases. However, the role of FGF21 on VC in vivo remains unclear. Thus, in this study, we observed the effect and mechanism of FGF21 on VC induced by vitamin D3 plus nicotine (VDN) treated rats. After four weeks' treatment, the calcium overload is mainly manifested in the increased blood pressure, aortic calcium content and ALP activity. Also, the HE and Alizarin-red S staining showed the structural damage of calcified vessel walls. In addition, the level of endogenous FGF21/β-Klotho/FGFR1 axis was up-regulated in the aortas of VC rats. Furthermore, exogenous FGF21 treatment significantly ameliorated the aortic injury and calcification in VC rats, and the level of β-Klotho and FGFR1 were furtherly increase. Moreover, FGF21 inhibited the osteogenic transition of VSMCs by down-regulating the expression of bone-associated proteins such as osteopontin (OPN), osteocalcin (OCN) and bone morphogenetic protein-2 (BMP-2), together with restored the expression of SM22α and SM α-actin, which are two of lineage markers in VSMCs. We provide the first evidence that FGF21 can inhibit the development of VC by inhibiting the osteogenic transition of VSMCs in rats. FGF21 might be an efficient endogenous vasoprotective factor for calcification.     

The distribution of melanopsin (OPN4) protein in the human brain

Until now, melanopsin (OPN4) – a specialized photopigment being responsive especially to blue light wavelengths – has not been found in the human brain at protein level outside the retina. More specifically, OPN4 has only been found in about 2% of retinal ganglion cells (i.e. in intrinsically photosensitive retinal ganglion cells), and in a subtype of retinal cone-cells. Given that Allen Institute for Brain Science has described a wide distribution of OPN4 mRNA in two human brains, we aimed to investigate whether OPN4 is present in the human brain also at protein level. Western blotting and immunohistochemistry, as well as immunoelectron microscopy, were used to analyse the existence and distribution of OPN4 protein in 18 investigated areas of the human brain in samples obtained in forensic autopsies from 10 male subjects (54 ± 3.5 years). OPN4 protein expression was found in all subjects, and, furthermore, in 5 out of 10 subjects in all investigated brain areas localized in membranous compartments and cytoplasmic vesicles of neurons. To our opinion, the wide distribution of OPN4 in central areas of the human brain evokes a question whether ambient light has important straight targets in the human brain outside the retinohypothalamic tract (RHT). Further studies are, however, needed to investigate the putative physiological phototransductive actions of inborn OPN4 protein outside the RHT in the human brain.     

The hypoxic peri-arteriolar glioma stem cell niche,an integrated concept of five types of niches in human glioblastoma

Glioblastoma is the most lethal primary brain tumor and poor survival of glioblastoma patients is attributed to the presence of glioma stem cells (GSCs). These therapy-resistant, quiescent and pluripotent cells reside in GSC niches, which are specific microenvironments that protect GSCs against radiotherapy and chemotherapy. We previously showed the existence of hypoxic peri-arteriolar GSC niches in glioblastoma tumor samples. However, other studies have described peri-vascular niches, peri-hypoxic niches, peri-immune niches and extracellular matrix niches of GSCs. The aim of this review was to critically evaluate the literature on these five different types of GSC niches. In the present review, we describe that the five niche types are not distinct from one another, but should be considered to be parts of one integral GSC niche model, the hypoxic peri-arteriolar GSC niche. Moreover, hypoxic peri-arteriolar GSC niches are structural and functional look-alikes of hematopoietic stem cell (HSC) niches in the bone marrow. GSCs are maintained in peri-arteriolar niches by the same receptor-ligand interactions as HSCs in bone marrow. Our concept should be rigidly tested in the near future and applied to develop therapies to expel and keep GSCs out of their protective niches to render them more vulnerable to standard therapies.     

Osteopontin gene expression in the aorta and the heart of propylthiouracil-induced hypothyroid mice

Summary It is known that there is abnormal osteopontin (OPN) expression at the sites of atherosclerotic lesions. In the Apolipoprotein E gene knockout (ApoE-KO) mouse, a model of the atherosclerotic process, altered cholesterol metabolism with associated increase in OPN expression is evident at 12–22 weeks in the aorta and at 22 weeks in the heart. In this study, we analyzed another animal model of hypothyroid mice created by ingestion of propylthiouracil (PTU). After 2 weeks of PTU ingestion, the animals had significant decreases in thyroid hormones (T3 and T4) and immediate increases in blood lipids/cholesterol. Hypothyroid mice showed 1.3-, 1.5-, 2-fold increases in blood levels of total cholesterol, triglycerides, and low density lipoprotein-cholesterol respectively. Semi-quantitative RT-PCR analysis showed that hypothyroid mice had 1.4- to 2-fold increases of OPN mRNA expression in the aorta and 1.5-fold increases in the heart. Hypothyroid animals treated with T3 (5 μg/day for 6 days) or statin (0.2 mg/30 g for 2 weeks) reduce blood lipids and aortic OPN mRNA expression. Data obtained with ELISA analyses showed 1.5- and 1.7-fold increases in OPN protein in the aorta (10 weeks) and the heart (22 weeks), respectively. This increase is close to the mRNA expression in both tissues of hypothyroid mice. In addition, western blots showed several variants of OPN protein expressed in the aorta and the heart. The decrease in the 70 kDa OPN is accompanied by an increase in 45 kDa OPN in the aorta of hypothyroid mice. In contrast, only 45 kDa OPN is found in the heart of control and hypothyroid mice. These data indicate that the increase of OPN mRNA and protein expression occurs in cardiovascular tissues of hypothyroid mice.     

H.pylori-L型感染及OPN表达与胃癌浸润转移的相关性研究

目的通过检测胃癌中幽门螺杆菌L型（Helicobacter pylori L-form,H.pylori-L型）感染以及骨桥蛋白（osteopontin,OPN）的表达情况,探讨H.pylori-L型在胃癌侵袭、转移中的作用。方法将胃癌BGC-823细胞与H.pylori-L型按不同比例共培养,细胞爬片进行免疫组化（SP法）检测BGC-823细胞OPN的表达情况。革兰染色及免疫组化检测120例胃癌组织中H.pylori-L型的感染情况。免疫组化检测胃癌组织中的OPN的表达。结果 （1）随着细菌比例增大,细胞爬片OPN阳性的胃癌BGC-823细胞数逐渐增加,各组之间差异有统计学意义（F=137.5,P〈0.01）。（2）胃癌组织H.pylori-L型阳性组的OPN表达阳性率为70.73%,显著高于H.pylori-L型阴性组OPN表达阳性率42.1%（P〈0.005）。胃癌中H.pylori-L型阳性率与肿瘤的大小、癌细胞的血管侵袭、浸润深度及淋巴结转移具有相关性（P〈0.001～P〈0.05）。（3）胃癌组织中H.pylori-L型阳性率与OPN的阳性表达呈正相关性（r=0.27,P〈0.001）。结论 H.pylori-L型感染增强了胃癌细胞的侵袭和转移能力,其机制可能与胃癌细胞的OPN表达量增加有关。