Bioinformatics identification of potentially involved microRNAs in Tibetan with gastric cancer based on microRNA profiling.

OBJECTIVE: The incidence of gastric cancer is high in Chinese Tibetan. This study aimed to identify the differentially expressed microRNAs (miRNAs) and further explore their potential roles in Tibetan with gastric cancer so as to predict potential therapeutic targets. METHODS: A total of 10 Tibetan patients (male:female = 6:4) with gastric cancer were enrolled for isolation of matched gastric cancer and adjacent non-cancerous tissue samples. Affymetrix GeneChip microRNA 3.0 Array was employed for detection of miRNA expression in samples. Differential expression analysis between two sample groups was analyzed using Limma package. Then, MultiMiR package was used to predict targets for miRNAs. Following, the target genes were put into DAVID (Database for Annotation, Visualization and Integrated Discovery) to identify the significant pathways of miRNAs. RESULTS: Using Limma package in R, a total of 27 differentially expressed miRNAs were screened out in gastric cancer, including 25 down-regulated (e.g. hsa-miR-148a-3p, hsa-miR-148b-3p and hsa-miR-363-3p) and 2 up-regulated miRNAs. According to multiMiR package, a number of 1445 target genes (e.g. Wnt1, KLF4 and S1PR1) of 13 differentially expressed miRNAs were screened out. Among those miRNAs, hsa-miR-148a-3p, hsa-miR-148b-3p and hsa-miR-363-3p were identified with the most target genes. Furthermore, three miRNAs were significantly enriched in numerous common cancer-related pathways, including "Wnt signaling pathway", "MAPK signaling pathway" and "Jak-STAT signaling pathway". CONCLUSIONS: The present study identified a downregulation and enrichment in cancer-related pathways of hsa-miR-148a-3p, hsa-miR-148b-3p and hsa-miR-363-3p in Tibetan with gastric cancer, which can be suggested as therapeutic targets.

High altitude genetic adaptation in Tibetans: no role of increased hemoglobin-oxygen affinity.

High altitude exerts selective evolutionary pressure primarily due to its hypoxic environment, resulting in multiple adaptive responses. High hemoglobin-oxygen affinity is postulated to be one such adaptive change, which has been reported in Sherpas of the Himalayas. Tibetans have lived on the Qinghai-Tibetan plateau for thousands of years and have developed unique phenotypes, such as protection from polycythemia which has been linked to PDH2 mutation, resulting in the downregulation of the HIF pathway. In order to see if Tibetans also developed high hemoglobin-oxygen affinity as a part of their genetic adaptation, we conducted this study assessing hemoglobin-oxygen affinity and their fetal hemoglobin levels in Tibetan subjects from 3 different altitudes. We found normal hemoglobin-oxygen affinity in all subjects, fetal hemoglobin levels were normal in all except one and no hemoglobin variants in any of the subjects. We conclude that increased hemoglobin-oxygen affinity or increased fetal hemoglobin are not adaptive phenotypes of the Tibetan highlanders.

Effect of Combined Hypoxia and High Fat Diet on eNOS/NO of Myocardium in Experimental Rats / 中国循环杂志

Objective: To investigate the effect of combined hypoxia and high fat diet (HFD) on endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) of myocardium in experimental rats with its possible mechanisms. Methods: A total of 60 male SD rats were randomly divided into 3 groups, n=20 in each group. Control group, the rats were fed by normal diet with normal oxygen condition. Hypoxia group, the rats were fed by normal diet with simulated 5000m altitude oxygen condition. Combined hypoxia and HFD (H+HFD) group, the rats were fed by HFD and simulated 5000m altitude oxygen condition. All animals were treated for 4 weeks and peripheral blood and myocardium specimen were collected. Hemoglobin was examined by automatic blood cell analyzer, plasma malondialdehyde (MDA) was measured by TBA method, superoxide dismutase (SOD) activity was detected by WST-1 method, mRNA and protein expressions of eNOS were examined by real time PCR and Western blot analysis respectively, the myocardium nitrates and nitrites (NOx) was measured by nitrate reductase method. Results: Compared with Control group, Hypoxia group and H+HFD group had increased mRNA and protein expressions of eNOS, H+HFD group had lower NOx levels than the other 2 groups P Conclusion: Upon hypoxia alone, H+HFD may further reduce NOx level of myocardium, it implies aggravated chronic hypoxia impairment, which might be related to dyslipidemia and lack of anti-oxidative ability in experimental rats.

Expression of aquaporin 2 in rat kidney under hypoxia at an altitude of 4600 m / 中华肾脏病杂志

Objective To investigate the change of aquaporin 2 (AQP2) mRNA and protein levels in renal collecting duct of SD rats after hypoxin caused by rising of the altitude to 4600 m. Methods Forty male SD rats were randomly divided into 4 groups (24 h, 48 h, 72 h and 1 week group), and 10 rats in Xining city were used as control group. All the 40 SD rats were transported to Kekexili Natural Reservation areas (4600 m) in Qinghai province. Rats of four experimental groups were sacrificed and renal tissue samples were harvested at different time point respectively, the control group rats were treated in Xining city (2260 m) as well. The concentration of plasma antidiuretic hormone (ADH) was measured by radioimmunity method. The expression of AQP2 mRNA and proteins was evaluated by real-time fluorescent quantitative-PCR, Western blot and immunofluorescence assay. Results The concentration of plasma ADH was decreased at 24 h and was only 28.5% of that of control group, reaching the lowest concentration at 48 h [(86.94±6.49) μg/L vs (302.5±310.48) μg/L], then it increased gradually and was similar to the control group at 7 d [(306.46±11.14) μg/L vs (302.53±10.48)μg/L, P＞ 0.05]. There were significant differences of the control group with 24 h, 48 h and 72 h groups, respectively[(302.53± 10.48) μg/L vs (142.46±10.57)μg/L, (86.94±6.49)μg/L, (169.65±11.15) μg/L respectively, P＜0.01]. The change of AQP2 gene expression level was consistent with the change of ADH. It was decreased at the begining when exposure to altitude and it reached its lowest level at 48 h. It was then returned to high level similarly to that of the control group at 7 d (0.09±0.01 vs 0.09± 0.008, P＞0.05 ). There were significant differences of the control group with 24 h, 48 h and 72 h group, respectively (0.09±0.008 vs 0.04±0.005, 0.03±0.002, 0.04±0.003 respectively, P＜0.01 ). Conclusions AQP2 expression in the renal collecting duct of SD rats is altered over the period exposed to altitude. It is decreased in the early hypoxia period, and is increased in later period. This change may be related to the intensity of hypoxia, which is mediated by a potential adaptation mechanisms against hypoxia caused by high altitude.

Molecular cloning and characterization of hemoglobin alpha and beta chains from plateau pika (Ochotona curzoniae) living at high altitude.

Hemoglobin (Hb) plays an important role in oxygen transfer from lung to tissues. Possession of a Hb with high oxygen affinity helps highland animals to adapt to high altitude, has been studied profoundly. Plateau pika (Ochotona curzoniae), a native species living at 3,000-5,000 m above sea level on Qinghai-Tibet Plateau, is a typical hypoxia and low temperature tolerant mammal. To investigate the possible mechanisms of plateau pika Hb in adaptation to high altitude, the complete cDNA and amino acid sequences of plateau pika hemoglobin alpha and beta chains have been described. Compared with human Hb, alterations in important regions can be noted: alpha111 Ala-->Asn, beta35 Tyr-->Phe, beta112 Cys-->Val, beta115 Ala-->Ser, and beta125 Pro-->Gln. Phylogenetic analysis of alpha and beta chains shows that plateau pika is closer to rabbit than to other species. This study provides essential information for elucidating the possible roles of hemoglobin in adaptation to extremely high altitude in plateau pika.

Molecular cloning of hemoglobin alpha-chain gene from Pantholops hodgsonii, a hypoxic tolerance species.

To investigate the possible mechanisms of high-altitude native animals in adapting to high altitude, we cloned hemoglobin alpha-chain (alpha-chain Hb) gene from Pantholops hodgsonii, an animal species that indigenously lives at elevations of 3700-5500 m on the Qinghai-Tibetan plateau. Using reverse transcription polymerase chain reaction (RT-PCR) technique, the alpha-chain Hb gene was amplified from total RNA in the liver of the Pantholops hodgsonii. TA cloning technique was used and the PCR product was cloned into pGEM-T vector. The DNA sequence of the gene was highly homologous with sheep (99.1%), goat (98.6%), cattle (95.6%) and human (86.5%). The alpha-chain Hb gene encoded a 142-amino acid protein that could be identified with the homology of alpha-chain Hb protein in sheep (98%), goat (96%), cattle (91%) and human (87%). However, 18 alternations were detected when compared with the alpha-chain Hb gene in human, and 2 in sheep. Moreover, the alterations of á117 GluAsp and alpha 132 AsnSer in important regions were noted in human and sheep, respectively. Phylogenetic analysis suggested that the structure of alpha-chain Hb was highly similar to that in sheep. This study provided essential information for elucidating the possible roles of hemoglobin in adapting to extremely high altitude in Pantholops hodgsonii.

Regulation of body weight by leptin, with special reference to hypoxia-induced regulation.

Since first cloned and reported by Zhang et al in 1994 (Nature 372:425), the obese gene and its product-leptin has been studied profoundly. Our knowledge in body weight regulation and the role played by leptin has increased substantially. Leptin serves as an adiposity signal to inform the brain of the adipose tissue mass in a negative feedback loop regulating food intake and energy expenditure. Many articles have reported weight loss at high altitude, but the explanation has been limited to loss of appetite. New ideas were highlighted after studies by Grosfeld et al and Ambrosini et al on the obese gene under hypoxia condition. Cells with hypoxia treatment upregulated obese gene transcription and suggested that enhancement of leptin secretion in vivo under hypoxia environment may be one of the potential therapeutic methods for obesity treatment.

Effect of Tibetan medicine Zuotai on in vivo pharmacokinetics of crocin-1 in rats / 中草药

Objective To study the effect of Tibetan medicine Zuotai on in vivo pharmacokinetics of crocin-1 in rats.Methods After im injection of crocin-1 (5 mg/kg) in control (continuously ig normal saline for 7 d) and expermental (continuously ig Zuotai suspension for 7 d or 21 d) rats,The plasma concentration of crocin-1 was determined by RP-HPLC,and plasma concentration-time data were analyzed by DAS 2.0 software to get the related pharmacokinetic parameters of crocin-1.Results After continuously ig administration of Zuotai [10 mg/(kg?d)] for 7 d and 12 d in experimental rats,the pharmacokinetic parameters of crocin-1 changed significantly.The AUC,Cmax,and MRT were significantly greater in experimental rats than those in control rats,and the CL and Vd were significantly lower than those in control rats,and the AUC of crocin-1 was greater in the 21 d administration group than that in the 7 d administration group.Conclusion The result demonstrates that Tibetan medicine significantly affects the pharmacokinetics of crocin-1 in rats.After administration of Zuotai in rats,the absorption degree of crocin-1 is significantly increased and the clearance rate is significantly decreased.

Protective effect and mechanisms of Sanweitanxiang powder on myocardial ischemia in rats / 中国药理学通报

Aim To explore protective effect of Sanweitanxiang powder on isoproterenol-induced myocardial ischemia in rats, and its possible mechanism. Methods A myocardial ischemia model in rats was established by intraperitoneal injection of isoproterenol (Iso 5 mg?kg-1 once a day ,for 3 days). After ip 24 h, The levels of LDH、CK in serum and NOS、iNOS and NO in the myocardium tissue were measured. The myocardial area suffered from ischemia injury were determined. The changes of myocardial ultrastructure were observed with electron microscope. Results Compared with model group, the levels of LDH、CK and infarction size of myocardium were decreased. The concentrations of NOS, iNOS and NO in myocardium were less than those in the model group. The results of myocardial ultrastructure indicated that the partial mitochondria crista and myofibrils sprase, z band unaltered in Sanweitanxiang powder groups. Conclusion Sanweitanxiang powder has a significant protective effect on isoproterenol-induced myocardial injury in rats. By improving the energy metabolism of myocardium,the structure and function of mitochondria and reducing the NO release.