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Xu M.,Peking University | Zhao M.,Peking University | Yang R.,Peking University | Yang R.,Beijing Hospital and Beijing Institute of Geriatrics | And 3 more authors.
International Immunopharmacology

This study investigated the effect of dietary nucleotides (NTs) on immune function in female Balb/C mice, which randomly distributed into six groups: one control group, one NF-free (NF) control group and four NT groups. NTs ranged from 0.0025% to 0.64%. Compared with the control group, the NF could significantly weaken the activity of T lymphocytes and macrophages, as well as decreased the activity of B lymphocytes and NK cell. NF significantly decreased the ratio of CD4+/CD8+, whereas, it increased Tr percentage. In comparison with the NF group, the concentration of serum IL-2 and IL-4 showed an increase trend. Meanwhile, the granular cell macrophages colony stimulating factor (GM-CSF) increased significantly in the 0.04% NT group. The ratio of Th1/Th2 also showed an increasing trend after the supplements of NTs. There were no significant differences between the control and 0.04% NT group. Nevertheless, no significant differences in weight gain and lymphoid organ indices were observed in our study. These results indicate that NT supplements can prevent hypoimmunity which result from NF diet. 0.04% NTs is the healthy optimal supply proportion in mice diet. © 2013 Elsevier B.V. All rights reserved. Source

Pang J.,Beijing Hospital and Beijing Institute of Geriatrics | Cui J.,Beijing Hospital and Beijing Institute of Geriatrics | Gong H.,Beijing Hospital and Beijing Institute of Geriatrics | Xi C.,Beijing Normal University | Zhang T.-M.,Beijing Hospital and Beijing Institute of Geriatrics
Journal of Cellular Physiology

High serum free fatty acids levels are associated with the development of insulin resistance in type 2 diabetes; however, the precise mechanisms underlying this lipid toxicity are unclear. To investigate whether PARP1 activation and NAD depletion are involved in the impairment of insulin sensitivity associated with lipotoxicity, HepG2 cells were cultured with 500μM oleic acid for 48h. Oleic acid-treated cells exhibited increased ROS generation, lipid accumulation and PARP1 activation. Treatment with the PARP1 inhibitor PJ34 and transfection with PARP1 small interfering RNA both prevented the oleic acid-induced impairment of the insulin signaling pathway. Furthermore, treatment with PJ34 reversed the oleic acid-induced decrease in intracellular NAD concentration, while exogenous NAD protected cells against oleic acid-induced insulin insensitivity. Combined NAD and PJ34 administration did not enhance the effects obtained by treatment with either NAD or PJ34 alone. Interestingly, when cells were treated with the SIRT1 inhibitor EX527, the protective effects of PJ34 and NAD treatment were diminished. Taken together, these data suggest that NAD depletion by PARP1 activation is essential for the modulation of insulin sensitivity in oleic acid-induced lipotoxicity. © 2014 Wiley Periodicals, Inc. Source

Pang J.,Beijing Hospital and Beijing Institute of Geriatrics | Xi C.,Beijing Normal University | Dai Y.,Peking Union Medical College | Gong H.,Beijing Hospital and Beijing Institute of Geriatrics | Zhang T.,Beijing Hospital and Beijing Institute of Geriatrics
Medical Science Monitor

It is widely accepted that chronic hyperglycemia induces DNA oxidative damage in type 2 diabetes, but little is known about the effect of hyperglycemia on the DNA repair system which plays a critical role in the maintenance of genomic DNA stability in diabetes. To investigate the alteration of base excision repair (BER) genes under hyperglycemia, the relative expression of the mRNAs of the BER genes ogg1, polb, lig3, xrcc1, and parp1 - were quantified using real-time PCR in HepG2 hepatocytes incubated with 5.5 mM or 30 mM glucose. High levels of glucose induced ROS accumulation and DNA damage, paralleling the dynamic alterations of BER mRNA expression. Compared to 5.5 mM glucose-treated cells, ogg1 and pol b mRNA expression transiently increased at day 1 and decreased after day 4 in cells exposed to 30 mM glucose. Exposure to 30 mM glucose increased the activity of PARP1, which led to reduced cellular NAD content and insulin receptor phosphorylation. Exposure to high concentrations of glucose initially led to the increased expression of BER mRNAs to counteract hyperglycemia-induced DNA damage; however, long-term exposure to high glucose concentrations reduced the expression of mRNA from BER genes, leading to accumulated DNA damage. © Med Sci Monit. Source

Wang Y.-H.,Wenzhou Medical College | Pan P.-P.,Beijing Institute of Geriatrics | Dai D.-P.,Beijing Hospital and Beijing Institute of Geriatrics | Wang S.-H.,Beijing Institute of Geriatrics | And 3 more authors.

1. CYP2C9 is an important member of the cytochrome P450 enzyme superfamily, with 57 CYP2C9 allelic variants being previously reported. Among these variants, we recently identified 21 novel alleles in the Han Chinese population. The aim of this study was to assess the catalytic activities of 36 CYP2C9 variants found in the Chinese population toward losartan in vitro. 2. Insect microsomes expressing the 36 CYP2C9 variants were incubated with 0.5-25μM losartan for 30min at 37°C. Next, the products were extracted, and signal detection was performed using high-performance liquid chromatography. 3. Compared with wild-type CYP2C9.1, the intrinsic clearance (Vmax/Km) values of all variants except for CYP2C9.56 were significantly altered. One variant exhibited markedly increased values (>250%), whereas 33 variants exhibited significantly decreased values (from 20 to 96%) due to increased Km and/or decreased Vmax values. 4. These findings suggest that more attention should be paid to subjects carrying these infrequent CYP2C9 alleles when administering losartan in the clinic. © 2014 Informa UK Ltd. Source

Dai D.-P.,Beijing Hospital and Beijing Institute of Geriatrics | Xu R.-A.,Wenzhou Medical College | Hu L.-M.,Wenzhou Medical College | Wang S.-H.,Wenzhou Medical College | And 10 more authors.
Pharmacogenomics Journal

Genetic polymorphisms of CYP2C9 significantly influence the pharmacokinetics and pharmacodynamics of some drugs, which might result in adverse drug effects and therapeutic failure. Several studies have been performed on CYP2C9 genetic polymorphisms in Han Chinese populations. However, these studies only focused on two commonly investigated alleles, *2 and *3, in relatively small sample sizes. To scale up the gene-scanning region and determine relatively precise data on the genetic distribution pattern in Chinese populations, unrelated healthy Han Chinese volunteers from Zhejiang Province (n=1127) and Hebei (n=1000) Province were recruited as subjects for the direct sequencing of all exons of CYP2C9. As a result, 14 previously reported alleles were detected in this work, and 8 of these alleles (*14, *16, *19, *23, *27, *29, *33 and *34) were described for the first time in Chinese populations. In addition, 37 novel mutations were also detected, of which 22 variants were non-synonymous, and 21 new alleles, *36-*56, were designated by the Human CYP Allele Nomenclature Committee. In vitro functional analysis of these 22 novel CYP2C9 variants revealed that 17 mutations had a significant influence on the protein's catalytic activity. Our study provides the most accurate data on CYP2C9 polymorphisms in Han Chinese populations and detects the largest number of novel allelic variants existing to date. These new alleles will greatly enrich the current knowledge of naturally occurring CYP2C9 variants in Chinese populations. © 2014 Macmillan Publishers Limited All rights reserved. Source

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