No abstract

We report that NSBP1, a nucleosome binding protein that affects the structure of chromatin, is highly expressed in mouse placenta. In Rcho-1 cells, which recapitulate the differentiation of trophoblast giant cells of living placenta, NSBP1 expression is linked to differentiation. Disregulation of NSBP1 protein levels, by either siRNA treatment or by overexpression, alters the expression of several members of the prolactin gene family without affecting the levels of several transcription factors involved in placental differentiation. Our studies identify NSBP1 as a nucleosome binding protein that modulates the expression of prolactin gene family members most likely by inducing changes in chromatin structure. Keywords CHROMOSOMAL PROTEINS; PLACENTA; GENE REGULATION; TROPHOBLAST; NSBP1Proper development and differentiation is contingent on the correct execution of a preprogrammed, orderly process that involves multiple, highly regulated, changes in gene expression. Given the central role of chromatin structure in regulating gene expression, it can be expected that structural chromatin-binding proteins such as members of the high mobility group (HMG) protein superfamily, could affect gene expression during differentiation [Reeves, 2001;Sgarra et al., 2004;Bianchi and Agresti, 2005;Hock et al., 2007].The high mobility group N (HMGN) proteins, a major family of the HMG superfamily, are unique among the numerous proteins that target chromatin in that they are the only nuclear proteins shown to specifically bind to the 147 base pair nucleosome core particle, the building block of the chromatin fiber [Bustin, 2001]. Studies with in vitro chromatin reconstitution systems, with cells grown in tissue culture, and with genetically altered mice revealed that [Bustin, 2001;Hock et al., 2007].We have previously described a gene coding for a novel protein named NSBP1 (Nucleosome Binding Protein 1, originally named NBP-45), which is structurally related to HMGNs but is not a typical HMGN protein [Shirakawa et al., 2000]. NSBP1 binds specifically to nucleosomes and can stimulate transcription from a reporter gene; however, the cellular function of this protein is not yet known. Our initial analyses revealed that NSBP1 transcripts are especially abundant in 7-day-old mice embryos, suggesting a role for the protein in mouse embryogenesis [Shirakawa et al., 2000]. We now report that the protein is highly expressed in placental rather than embryonic tissues, and is highly enriched in trophoblast giant cells, which play a key role in placental differentiation [Simmons and Cross, 2005;Simmons et al., 2008]. To gain insights into its possible function in placental development, we examined its role in regulating the expression prolactin gene family members in Rcho-1 cells, a cell line that serves as a model system for studies on the development of trophoblast giant cells [Hamlin et al., 1994]. In these cells the expression of specific lactogens is linked to differentiation in a manner similar to their expression in living placent...

We have demonstrated previously that both acute and chronic oral administration of adenosine have novel functions such as anti-hypertensive effects and improved hyperlipidaemia in stroke-prone spontaneously hypertensive rats (SHRSP) fed a normal diet. The purpose of the present study was to investigate the effect of adenosine administration on metabolic syndrome-related parameters in SHRSP fed a high-fat diet. Six-week-old rats were divided into three groups, and were administered either water (control) or adenosine (10 or 100 mg/l) for 8 weeks. During this period, the rats had free access to a high-fat diet based on AIN-93M. The results showed that hypertension, plasma lipid, NO, insulin, glucose and urinary 8-hydroxy-2 0 -deoxyguanosine levels improved significantly in both adenosine groups. The mRNA expression levels of genes involved in anti-oxidative activity and adenosine receptors were also altered in the adenosine groups. Administration of adenosine also increased plasma adiponectin levels, accompanied by upregulation of mRNA expression level of adiponectin and adiponectin receptor 1 in perirenal fat and adiponectin receptor 2 in the liver. In conclusion, oral administration of adenosine is effective for improving metabolic syndrome-related parameters in SHRSP, and accordingly it may prevent the progression of the metabolic syndrome. High-fat diet: Blood pressure: Glucose metabolism: Lipid profileObesity has become increasingly prevalent worldwide as a result of changes in lifestyle, especially eating habits, and it is involved in the aetiology of a number of conditions such as CVD, hypertension, stroke and diabetes (1,2) . Overconsumption of high-energy food and lower energy expenditure have resulted in an alarming increase in the incidence of obesity (3) . The fact that clinically diagnosed insulin resistance, hypertension, increased fat distribution and high plasma TAG levels have been associated with the development of diseases associated with metabolic syndrome-related parameters has attracted attention from the scientific community. Prevention and improvement of obesity and metabolic syndrome-related diseases are therefore important issues in modern society, and represent an effective strategy for the promotion of better health.Adenosine is an endogenous purine nucleoside that modulates many physiological processes, with these effects being mediated by the activation of specific subtypes of adenosine receptors, termed A 1 , A 2A , A 2B and A 3 ( 4,5) . Adenosine can be extracted from plant and mammalian tissues. Higher adenosine concentrations in the plant and mammalian tissues result from enhanced excretion of adenosine or diminished uptake of adenosine (6) . Previous studies have provided evidence to support the physiological role of adenosine in general health. For example, studies in both rats and human subjects showed that oral administration of adenosine in sucrose solutions decreased blood glucose and insulin concentrations due to its inhibitory effect on a-glucosidase (7,8) . Continuous int...

DNA fragmentation is a hallmark of apoptosis that occurs in a variety of cell types; however, it remains unclear whether caspase‐3 is required for its induction. To investigate this, we produced caspase‐3 knockout Chinese hamster ovary (CHO)‐K1 cells and examined the effects of gene knockout and treatment with caspase‐3 inhibitors. Okadaic acid (OA) is a potent inhibitor of the serine/threonine protein phosphatases (PPs) PP1 and PP2A, which induce apoptotic cellular reactions. Treatment of caspase‐3−/− cells with OA induced DNA fragmentation, indicating that caspase‐3 is not an essential requirement. However, in the presence of benzyloxycarbonyl‐Asp‐Glu‐Val‐Asp (OMe) fluoromethylketone (z‐DEVD‐fmk), DNA fragmentation occurred in CHO‐K1 cells but not in caspase‐3−/− cells, suggesting that caspase‐3 is involved in OA‐induced DNA fragmentation that does not utilize DEVDase activity. In the absence of caspase‐3, DEVDase activity may play an important role. In addition, OA‐induced DNA fragmentation was reduced but not blocked in CHO‐K1 cells, suggesting that caspase‐3 is involved in caspase‐independent OA‐induced DNA fragmentation. Furthermore, OA‐induced cleavage of caspase‐3 and DNA fragmentation were blocked by pretreatment with the wide‐ranging serine protease inhibitor 4‐(2‐aminoethyl)‐benzenesulfonyl fluoride hydrochloride. These results suggest that serine proteases regulate DNA fragmentation upstream of caspase‐3.

Late-onset hypogonadism, a male age-related syndrome characterized by a decline in testosterone production in the testes, is commonly treated with testosterone replacement therapy, which has adverse side effects. Therefore, an alternative treatment is highly sought. Supplementation of a high dosage of biotin, a water-soluble vitamin that functions as a coenzyme for carboxylases involved in carbohydrate, lipid, and amino acid metabolism, has been shown to influence testis functions. However, the involvement of biotin in testis steroidogenesis has not been well clarified. In this study, we examined the effect of biotin on testosterone levels in mice and testis-derived cells. In mice, intraperitoneal treatment with biotin (1.5 mg/kg body weight) enhanced testosterone levels in the serum and testes, without elevating serum levels of pituitary luteinizing hormone. To investigate the mechanism in which biotin increased the testosterone level, mice testis-derived I-10 cells were used. The cells treated with biotin increased testosterone production in a dose- and time-dependent manner. Biotin treatment elevated intracellular cyclic adenosine monophosphate levels via adenylate cyclase activation, followed by the activation of protein kinase A and testosterone production. These results suggest that biotin may have the potential to improve age-related male syndromes associated with declining testosterone production.