Objective To observe the effects of orexin-1 receptor inhibitor on proliferation and estrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Methods BMSCs were isolated and cultured from Sprague-Dawley rats, and orexin-1 receptor inhibitor was prepared to different concentration of solutions: 10-2, 10-3, 10-4, 10-5 and 10-6 mol·L-1. Then, the cells at passage 3 were cultured in orexin-1 receptor inhibitor solutions. The cell growth, alkaline phosphatase activity and osteocalcin secretion were measured by MTT, PNPP and ELISA, respectively. The mRNA expression levels of Runx2 and COL1A1 were detected by real-time quantitative PCR. Results The best concentration of orexin-1 receptor inhibitor for the proliferation of BMSCs was 1×10-4 mol·L-1. Orexin-1 receptor inhibitor promoted the proliferation at concentration of 10-6, 10-5, 10-4 mol·L-1 in 3, 5 and 7 days. Orexin-1 receptor inhibitor at concentration of 10-6, 10-5 and 10-4 mol·L-1 for 5 days significantly stimulated ALP activity. Orexin-1 receptor inhibitor significantly up-regulated Runx2 and COL1A1 mRNA expression at concentration of 10-6, 10-5, 10-4 mol·L-1 for 5 days (P<0.05). Conclusion Orexin-1 receptor inhibitor can promote BMSCs proliferation and stimulated ALP activity and osteocalcin secretion.
MENG XW.Epidemiology of osteoporosis in mainland China[J].J Bone Miner Metab,2005,23(Suppl):76-77.
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WEIW,MOTOIKET,KRZESZINSKI JY,et al.Orexin re-gulates bone remodeling via a dominant positive central action and a subordinate negative peripheral action[J].Cell Metabolism,2014,6(19):927-940.
Orexin neuropeptides promote arousal, appetite, reward, and energy expenditure. However, whether orexin affects bone mass accrual is unknown. Here, we show that orexin functions centrally through orexin receptor 2 (OX2R) in the brain to enhance bone formation. OX2R null mice exhibit low bone mass owing to elevated circulating leptin, whereas central administration of an OX2R-selective agonist augments bone mass. Conversely, orexin also functions peripherally through orexin receptor 1 (OX1R) in the bone to suppress bone formation. OX1R null mice exhibit high bone mass owing to a differentiation shift from marrow adipocyte to osteoblast that results from higher osseous ghrelin expression. The central action is dominant because bone mass is reduced in orexin null and OX1R2R double null mice but enhanced in orexin-overexpressing transgenic mice. These findings reveal orexin as a critical rheostat of skeletal homeostasis that exerts a yin-yang dual regulation and highlight orexin as a therapeutic target for osteoporosis.
LIU RF,LI JQ,HOU RX,et al.Impact of BMSCs from different sources on proliferation of C cells[J].Genet Mol Res,2015,14(1):474-482.
Abstract There are significant differences on the biological characteristics of bone marrow mesenchymal stem cells (BMMSCs), immunological response, and antigen-presenting functions between patients with psoriasis and normal subjects, but there are no significant differences in aborted fetuses. We examined the differences in BMMSCs between aborted fetuses and patients with psoriasis in this study. Bone marrow from normal subjects, aborted fetuses, and patients with psoriasis were obtained using a MidiMACS machine. Density gradient centrifugation method was used to isolate the bone marrow mononuclear cells of patients with psoriasis and aborted fetus and the cells were cultivated. Bone marrow CD34(+) cells from normal subjects were isolated. MTT colorimetric detection was used to test the proliferation activity of bone marrow CD34(+) cells. The purity of bone marrow CD34(+) cells and BMMSCs was determined by flow cytometry. The BMMSC culture supernatant fluid of patients with psoriasis and aborted fetuses showed no statistically significant difference with bone marrow CD34(+) cell proliferation in normal subjects (P > 0.05).
SAKURAIT,AMENMIYAA,ISHIIM,et al.Orexins and orexin receptors:a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior[J].Cell,1998,92(4):573-585.
The hypothalamus plays a central role in the integrated control of feeding and energy homeostasis. We have identified two novel neuropeptides, both derived from the same precursor by proteolytic processing, that bind and activate two closely related (previously) orphan G protein-coupled receptors. These peptides, termed orexin-A and -B, have no significant structural similarities to known families of regulatory peptides. prepro-orexin mRNA and immunoreactive orexin-A are localized in neurons within and around the lateral and posterior hypothalamus in the adult rat brain. When administered centrally to rats, these peptides stimulate food consumption. prepro-orexin mRNA level is up-regulated upon fasting, suggesting a physiological role for the peptides as mediators in the central feedback mechanism that regulates feeding behavior.
The hypothalamic orexin neuropeptide acutely promotes appetite, yet orexin deficiency in humans and mice is associated with obesity. Prolonged effects of increased orexin signaling upon energy homeostasis have not been fully characterized. Here, we examine the metabolic effects of orexin gain of function utilizing genetic and pharmacologic techniques in mice. Transgenic orexin overexpression confers resistance to high-fat diet-induced obesity and insulin insensitivity by promoting energy expenditure and reducing consumption. Genetic studies indicate that orexin receptor-2 (OX2R), rather than OX1R signaling, predominantly mediates this phenotype. Likewise, prolonged central administration of an OX2R-selective peptide agonist inhibits diet-induced obesity. While orexin overexpression enhances the anorectic-catabolic effects of central leptin administration, obese leptin-deficient mice are completely resistant to the metabolic effects of orexin overexpression or OX2R agonist infusion. We conclude that enhanced orexin-OX2R signaling confers resistance to diet-induced features of the metabolic syndrome through negative energy homeostasis and improved leptin sensitivity.
HAYNES AC,CHAPMANH,TAYLORC,et al.Anorectic,thermogeni and anti-obesity activity of a selective orexin-1 receptor antagonist in ob /ob mice[J].Regul Pept,2002,104(1/3) :153-159.
A single dose of the orexin-1 (OX 1 ) receptor antagonist 1-(2-methylbenzoxazol-6-yl)-3-[1,5] naphthyridin-4-yl urea hydrochloride (SB-334867-A) reduces orexin-A-induced feeding and natural feeding in Sprague Dawley rats. In this study, the anti-obesity effects of SB-334867-A were determined in genetically obese ( ob / ob ) mice dosed with SB-334867-A (30 mg/kg, i.p.) once daily for 7 days, and then twice daily for a further 7 days. SB-334867-A reduced cumulative food intake and body weight gain over 14 days. Total fat mass gain, determined by Dual Emission X-ray Absorptiometry, was reduced, while gain in fat-free mass was unchanged. Fasting (5 h) blood glucose was also reduced at the end of the study, with a trend to reduced plasma insulin. Interscapular brown adipose tissue (BAT) weight was reduced, the tissue was noticeably darker in colour and quantitative PCR (TaqMan) analysis of this tissue showed a trend to an increase in uncoupling protein-1 mRNA expression, suggesting that SB-334867-A might stimulate thermogenesis. This was confirmed in a separate study in which a single dose of SB-334867-A (30 mg/kg, i.p.) increased metabolic rate over 4 h in ob / ob mice. OX 1 receptor mRNA was detected in BAT, and its expression was increased by 58% by treatment with SB-334867-A. This is the first demonstration that OX 1 receptor antagonists have potential as both anti-obesity and anti-diabetic agents.
ZIOLKOWSKA,A,RUCINSKI,M,TYCZEWSKAM,et al.Orexin B inhibits proliferation and stimulates specialized function of cultured rat calvarial osteoblast-like cell[J].Int J Mol Med,2008,22(6):749-755.
Abstract Orexin-A (OXA) and orexin-B (OXB) are polypeptides derived from the same 130 amino acid long precursor (prepro-orexin) that bind and activate two closely related orphan G protein-coupled receptors OX1-R and OX2-R. These hypothalamic neuropeptides stimulate food intake and energy expenditure and play a significant role in sleep-wakefulness regulation. Present studies aimed to investigate the effects of orexins on proliferative activity and osteocalcin secretion by cultured rat calvarial osteoblast-like (ROB) cells. Conventional RT-PCR methods detected expression of the OX1-R gene in freshly isolated ROB cells and cells cultured for 7, 14 and 21 days. In contrast, at all time points tested, expression of prepro-OX or OX2-R genes was not demonstrated. QPCR revealed the highest expression of OX1-R gene in freshly isolated bone cells and a notably lower one in cultured ROB cells. Exposure of cultured cells to both OXA and OXB stimulated expression of the OX1-R gene. However, this effect was seen at the lowest tested concentration (1x10(-10) M). Exposure of cultured ROB cells to OXA for 48 h did not change osteocalcin concentrations in media analyzed at days 7, 14 and 21 of culture. On the contrary, OXB notably stimulated osteocalcin concentrations in media taken at days 14 and 21 of culture. In contrast, OXA exerted a notable inhibitory effect on the proliferative activity of ROB cells at day 7 of culture, while OXB exerted a similar effect at day 14. Thus, the obtained results suggest that: (i)(ROB) cells are provided with functional OX1-R gene; (ii) in ROB cells expression of this gene seems to be up-regulated by low concentrations of both OXA and OXB; (iii) OXB exerts inhibitory effects on proliferative activity and stimulating effects on osteocalcin secretion by cultured ROB cells; (iv) rat calvarial osteoblasts provided with OX receptor may be a target for circulating orexins. Thus, orexins may be included in the expanding group of neuropeptides involved in the physiological regulation of the major bone cell types.
, 纳青青, 吴天秀
