Adenosine 2A receptor contributes to the facilitation of post-infectious irritable bowel syndrome by γδ T cells via the PKA/CREB/NF-κB signaling pathway.

BACKGROUND: Immunological dysfunction-induced low-grade inflammation is regarded as one of the predominant pathogenetic mechanisms in post-infectious irritable bowel syndrome (PI-IBS). γδ T cells play a crucial role in innate and adaptive immunity. Adenosine receptors expressed on the surface of γδ T cells participate in intestinal inflammation and immunity regulation. AIM: To investigate the role of γδ T cell regulated by adenosine 2A receptor (A2AR) in PI-IBS. METHODS: The PI-IBS mouse model has been established with Trichinella spiralis (T. spiralis) infection. The intestinal A2AR and A2AR in γδ T cells were detected by immunohistochemistry, and the inflammatory cytokines were measured by western blot. The role of A2AR on the isolated γδ T cells, including proliferation, apoptosis, and cytokine production, were evaluated in vitro. Their A2AR expression was measured by western blot and reverse transcription polymerase chain reaction (RT-PCR). The animals were administered with A2AR agonist, or A2AR antagonist. Besides, γδ T cells were also injected back into the animals, and the parameters described above were examined, as well as the clinical features. Furthermore, the A2AR-associated signaling pathway molecules were assessed by western blot and RT-PCR. RESULTS: PI-IBS mice exhibited elevated ATP content and A2AR expression (P < 0.05), and suppression of A2AR enhanced PI-IBS clinical characteristics, indicated by the abdominal withdrawal reflex and colon transportation test. PI-IBS was associated with an increase in intestinal T cells, and cytokine levels of interleukin-1 (IL-1), IL-6, IL-17A, and interferon-α (IFN-α). Also, γδ T cells expressed A2AR in vitro and generated IL-1, IL-6, IL-17A, and IFN-α, which can be controlled by A2AR agonist and antagonist. Mechanistic studies demonstrated that the A2AR antagonist improved the function of γδ T cells through the PKA/CREB/NF-κB signaling pathway. CONCLUSION: Our results revealed that A2AR contributes to the facilitation of PI-IBS by regulating the function of γδ T cells via the PKA/CREB/NF-κB signaling pathway.

Cloning and identification of a novel thyroid hormone receptor ß isoform expressed in the pituitary gland.

We have previously identified a novel Trß isoform (TrßΔ) in the rat, in which a novel exon N (108 bps) was found between exon 3 and exon 4 of TrßΔ, which represents the only difference between TrßΔ and Trß1. In this study, we searched for an elongated Trß2-like subtype with one additional exon N. We successfully isolated the entire mRNA/cDNA of a novel elongated Trß2 isoform via PCR in the rat pituitary gland. The mRNA/cDNA was only 108 bps (exon N) longer than that Trß2, and the extension of the sequence was between exon 3 and 4 of Trß. The whole sequence of this novel Trß isoform has been published in NCBI GenBank (HM043807.1); it is named TRbeta2Delta (Trß2Δ). In adult rat pituitary tissue, quantitative real-time RT-PCR analysis showed that the mRNA levels of Trß2Δ and Trß2 were roughly equal (P > 0.05). We cloned, expressed, and purified the His-Trß2Δ protein [recombinant TRß2Δ (rTRß2Δ)]. SDS-PAGE and western blotting revealed that the molecular weight of rTRß2Δ was 58.2 kDa. Using a radioligand binding assay and an electrophoretic mobility shift assay, rTRß2Δ-bound T3 with high affinity and recognized thyroid hormone response element (TRE) binding sites. Finally, in vitro transfection experiments further confirmed that rTRß2Δ binding T3 significantly promotes the transcription of target genes via the TRE. Here, we have provided evidence suggesting that rTRß2Δ is a novel functional TR isoform.

Selection of suitable reference genes for normalization of quantitative real-time PCR in cartilage tissue injury and repair in rabbits.

When studying the altered expression of genes associated with cartilage regeneration by quantitative real-time RT-PCR (RT-qPCR), reference genes with highly stable expression during different stages of chondrocyte developmental are necessary to normalize gene expression accurately. Until now, no reports evaluating expression changes of commonly used reference genes in rabbit articular cartilage have been published. In this study, defects were made in rabbit articular cartilage, with or without insulin-like growth factor 1 (IGF-1) treatment, to create different chondrocyte living environments. The stability and intensity of the expressions of the candidate reference genes glyceraldehyde-3-phosphate dehydrogenase (GAPDH), 18S Ribosomal RNA (18S rRNA), cyclophilin (CYP), hypoxanthine phosphoribosyl transferase (HPRT1), and beta-2-microglobulin (B2M) were evaluated. The data were analyzed by geNorm and NormFinder. B2M and 18S rRNA were identified to be suitable reference genes for rabbit cartilage tissues.

Decreased expression of retinoblastoma protein-interacting zinc-finger gene 1 in human esophageal squamous cell cancer by DNA methylation.

BACKGROUND: To study the expression of the RIZ1 (Retinoblastoma protein-interacting zinc-finger gene 1) gene and investigate the promoter region methylation status of RIZ1 gene in the human esophageal squamous cell carcinoma (ESCC) cell lines of KYSE150, KYSE510, TE13, EC9706, CaEsl7, and EC109. To investigate the influence of DNMT (DNA methyltransferase) 5-aza-CdR(5-aza-2'-deoxycytidine) on the transcription of the RIZ1 gene in one cell line whose RIZ1 gene promoter region methylation was detected, and to investigate its influence on the cell proliferation. METHODS: Real-time PCR (Real-time quantitative PCR) and an immunohistochemistry technique was used to get the expression of RIZ1 in specimens from 6 human ESCC cell lines and 28 ESCC patients (tumor tissues and adjacent non-cancerous tissues). MSP (Methylation-specific PCR) was used to investigate the promoter region methylation status of the RIZ1 gene in the 6 ESCC cell lines. One cell line, whose RIZ1 gene promoter region methylation was detected, was chosen for the next studies in which it was treated it by with 5-aza-CdR. Real-time PCR was used to investigate its influence on the transcription of RIZ1 gene and MTT (methyl thiazolyl tetrazolium) was used to detect if 5-aza-CdR inhibits the proliferation of the cell line. RESULTS: In the 28 ESCC patient samples, RIZ1 expression was significantly lower in the tumor tissues than that in their adjacent non-cancerous tissues (p < 0.05). Consistently, immunohistochemistry analyses of RIZ1 protein expression showed that in the ESCC tissues RIZ1 protein expression was also significantly lower than in the adjacent tissues. In the human ESCC tissues the rate of expression accounts for 0% (0/12), and in the adjacent noncancerous tissues the rate of expression was 66.7% (8/12), the correlation was highly significant (chi2 = 12.000, p < 0.05). Promoter methylation of the RIZ1 gene was detected in TE13, CaEsl7, EC109. The cell line TE13 was chosen for the next studies. The expression of RIZ1 mRNA in TE-13 was up-regulated after having been treated with 5-aza-CdR. 5-aza-CdR inhibited cell proliferation of TE-13 in a time and concentration-dependent manner. CONCLUSIONS: Promoter methylation may play an important role in the epigenetic silencing of RIZ1 gene expression. Methylation of the RIZ1 promoter and loss of RIZ1 expression in human ESCC are independent biomarkers. Their determination may offer guidance for selecting appropriate diagnoses and treatments. RIZ1 may be a potential tumor suppressor in human ESCC.

[Effects of supplement of thyroxine for hypothyroid pregnant rat on the expression of homeobox gene Nkx2.1 mRNA in the offspring's cerebrum tissue].

OBJECTIVE: To explore the effects of thyroid hormone on the expression of homeobox gene Nkx2.1 mRNA in child rat by supplying their hypothyroidism pregnant mother with different dose of levothyroxine (L-thyroxine, L-T(4)) in different times. METHODS: 120 female Wistar rats were randomly divided into eight groups according to the body weight: control group, non-treatment hypothyroidism group, hypothyroidism groups supplied with L-T(4) in high, medium and low dosage in early stage (1st-17th day of pregnancy) and in late stage (18th day of pregnancy-20th day after childbirth). According to 100 grams of body weight, the concentrations of L-T(4) were 3.5, 2.0, 0.5 µg/d in high, medium and low dosage group. All the rats were fed with low-iodine food. The control group was given 200 µg/L potassium iodate solution as drinking water and the other groups were given deionized water. After three months, the rats were mated with normal male rats. After the pregnancy was confirmed, hypothyroidism groups were supplied with L-T(4) of different concentrations. Brain samples were taken from the 17-day fetal rats, new-born and 20-day old offsprings and the levels of Nkx2.1 mRNA in brain tissue were analyzed by real-time fluorescence quantitative PCR techniques. RESULTS: The levels of TT(3) in hypothyroidism groups supplied with L-T(4) in high, medium and low dosages in early and late pregnant stages, non-treatment hypothyroidism group and control group were (0.85 ± 0.17), (0.81 ± 0.18), (0.86 ± 0.21), (0.85 ± 0.20), (0.89 ± 0.18), (0.85 ± 0.20), (0.86 ± 0.20), (1.08 ± 0.07) nmol/L (F = 4.08, P < 0.01); the levels of TT(4) in each group were (0.43 ± 0.16), (0.39 ± 0.11), (0.39 ± 0.13), (0.43 ± 0.17), (0.51 ± 0.19), (0.43 ± 0.16), (0.41 ± 0.15), (39.43 ± 14.16) nmol/L (F = 31.99, P < 0.01); the levels of FT(3) in each group were (3.29 ± 0.61), (3.29 ± 0.61), (3.24 ± 0.61), (3.28 ± 0.63), (3.31 ± 0.59), (3.28 ± 0.50), (3.24 ± 0.49), (4.93 ± 0.46) pmol/L (F = 5.79, P < 0.01); the levels of FT(4) in each group were (3.38 ± 0.80), (3.31 ± 0.67), (3.29 ± 0.73), (3.27 ± 0.71), (3.48 ± 0.81), (3.56 ± 0.66), (3.29 ± 0.61), (27.29 ± 4.53) pmol/L (F = 26.34, P < 0.01). The expression of Nkx2.1 mRNA in non-treatment hypothyroidism group (9.15 × 10(-5) ± 9.17 × 10(-5)) was lower than control group (65.1 × 10(-5) ± 40.90 × 10(-5)) in 17th day of pregnancy (t = 66.224, P < 0.05); the expression of Nkx2.1 mRNA in non-treatment hypothyroidism group (3.16 × 10(-5) ± 0.142 × 10(-5)) was lower than control group (55.6 × 10(-5) ± 51.05 × 10(-5)) in new-born (t = 102.225, P < 0.05); the expression of Nkx2.1 mRNA in non-treatment hypothyroidism group (8.09 × 10(-5) ± 8.21 × 10(-5)) was lower than control group (13.9 × 10(-5) ± 7.43 × 10(-5)) in 20th day after birth (t = 9.235, P < 0.05). The trend of Nkx2.1 mRNA in hypothyroidism groups was decreased in group supplied with L-T(4) in medium dosage in early stage descends in 17th day of pregnancy, new-born and 20th day after birth (57.1 × 10(-5) ± 22.90 × 10(-5)), (30.8 × 10(-5) ± 27.20 × 10(-5)), (17.1 × 10(-5) ± 0.623 × 10(-5)) (F = 13.394, P < 0.01). The expression of Nkx2.1 mRNA in hypothyroidism groups supplied with L-T(4) in medium dosage in early stage in 17th day of pregnancy, new-born and 20th day after childbirth was closest to the control group in every period (t values were 0.225, 0.336, 0.345, all P values > 0.05). CONCLUSION: The difference in the expression of homeobox gene Nkx2.1 mRNA is highly related to the level of thyroid hormone.

Sleep-related hypoxemia aggravates systematic inflammation in emphysematous rats.

BACKGROUND: Sleep disturbance is common in patients with emphysema. This study aimed to develop a novel model of sleep-related hypoxemia (SRH) in emphysema (SRHIE) with rats, and to explore the inflammatory status of SRHIE in lung, liver, pancreas, carotid artery and whole blood. METHODS: Seventy-five male Wistar rats were assigned to 5 groups with 15 per group according to the exposure conditions. The protocols varied with the degree of hypoxia exposure and severity of pre-existing emphysema caused by cigarette smoke exposure: (1) SRH control (SRHCtrl) group, sham smoke exposure (smoke exposure, exposed to smoke of 15 cigarettes twice everyday, 16 weeks) and SRH exposure (12.5% O2, 3 hours, SRH exposure, divide total hypoxia time (1.5 hours or 3 hours) into 4 periods evenly (22.5 minutes or 45 minutes) and distribute these hypoxia periods evenly into physiological sleep time of rats identified by electroencephalogram, week 9 to week 16); (2) Emphysema control (ECtrl) group, smoke exposure and sham SRH exposure (21% O2, 3 hours); (3) Short SRH in emphysema (SRHShort) group, smoke exposure and short SRH exposure (12.5% O2, 1.5 hours); (4) Mild SRH in emphysema (SRHMild) group, smoke exposure and mild SRH exposure (15% O2, 3 hours); (5) Standard SRH in emphysema (SRHStand) group, smoke exposure and SRH exposure (12.5% O2, 3 hours). ECtrl, SRHShort, SRHMild and SRHStand groups were groups with emphysematous rats. Two days before the end of exposure, 5 rats in each group were randomly selected for arterial blood gas analysis. In the rest 10 rats in each group, we obtained blood samples and bronchoalveolar lavage fluid (BALF) for routine tests. We also obtained tissue blocks of lung, liver, pancreas, and right carotid artery for pathologic scoring and measurements of liver oxidative stress (measuring hepatic oxidative stress enzymes, superoxide dismutase (SOD) activity, catalase (CAT) activity and malondialdehyde (MDA) concentration). RESULTS: Emphysematous groups had higher mean linear intercept (MLI) and mean alveolar number (MAN) values than SRHCtrl group. MLI values in SRHStand group were the highest (all P < 0.05). O2Sat in SRHStand rats when SRH exposure was (83.45 ± 1.76)%. Histological scores of lung, liver, pancreas and right carotid artery were higher in emphysematous groups than SRHCtrl group, and SRHStand group were the highest (all P < 0.05) (SOD and CAT values were lower and MDA values were higher in groups with emphysema than without and in SRHStand group than in ECtrl group (all P < 0.05)). MDA values were the highest in SRHStand group (all P < 0.05). Total cellular score in BALF and White blood cell (WBC) in whole blood were the highest in SRHStand group (all P < 0.05). Lymphocyte ratios were the highest in SRHStand group both in BALF and blood (all P < 0.05). Red blood cell (RBC) and hemoglobin in emphysematous groups were higher than that in SRHCtrl group, and SRHStand group were higher than ECtrl group (all P < 0.05). CONCLUSIONS: With a proper novo model of SRHIE with Wistar rats, we have demonstrated SRH may aggravate the degree of emphysematous changes, polycythemia, oxidative stress and systematic inflammation. SRH and emphysema may have a synergistic action in causing systematic damages, and lymphocyte may be playing a central role in this process. Longer duration and more severe extent of SRHIE exposure also seem to result in more serious systematic damages. The mechanisms of all these concerned processes remain to be studied.

[Overdose of iodine on expression of CCK gene in rat brains].

OBJECTIVE: To observe the effect of overdose iodine on the expression of CCK gene in brains of rats and identify the possible mechanisms. METHODS: One-month weaning Wistar rats were randomly divided into five groups which were fed with normal feedstuff and water supplemented with different concentrations of potassium iodide, named A group (iodine ration was about 6.15 microg per day), B group (iodine ration was about 30.75 microg per day), C group (iodine ration was about 61.5 microg per day), D group (iodine ration was about 307.5 microg per day) and E group (iodine ration was about 615 microg per day). Rats were sacrificed after being fed for three or six months. Then serum thyroid hormones were measured by radioimmunoassay and the mRNA level of CCK gene was studied by using RT-PCR technique. RESULTS: At the end of three months, the values of thyroid hormones in E group [TT4 (45.2 +/- 13.7) nmol/L, TI'3 (0.65 +/- 0.20) nmol/L, FT3 (0.93 +/- 0.45) pmol/L, FT4 (7.07 +/- 2.43) pmol/L, rT3 (0.15 +/- 0.04) nmol/L] were all lower than those in A group [TT4 (76.0 +/- 18.8) nmol/L, TT3 (1.34 +/- 0.41) nmol/L, FT3 (2.45 +/- 0.62) pmol/L, FT4 (15.12 +/- 3.40) pmol/L, rT3 (0.24 +/- 0.04) nmol/L]. There were significant differences between E group and A group on the levels of serum TH (F values are 14.68, 16.03, 21.16, 20.25, 13.52 respectively, P < 0.01); FT3 levels in C and D groups were significantly decreased as compared to A and B groups (F = 21.16, P < 0.05). rT3 level in D group was significantly decreased compared with A,B and C groups (F = 13.52, P < 0.05). At the end of six months, the levels of serum TH in E group (TT4 (51.84 +/- 15.83) nmol/L, TT3 (0.77 +/- 0.22) nmol/L, FT4 (6.88 +/- 2.23) pmol/L, FT3 (0.74 +/- 0.28) pmol/L, rT3 (0.14 +/- 0.03) nmol/L) were lower than those in any other groups (F values were 6.05, 12.22, 11.25, 13.42, 5.89 respectively, P < 0.05). At the end of both three and six months, the mRNA levels of CCK gene in E group were lower than any other groups (F values were 4.04, 3.95 respectively, P < 0.01). The results of correlation analysis showed that serum FT4 had linear correlation with levels of CCK mRNA (r values were 0.990, 0.948 respectively; P < 0.05); However serum FT3 had no linear correlation with the levels of CCK mRNA (r values are 0.970, 0.932 respectively). CONCLUSIONS: Exposure to overdose of iodine (iodine ration was 100-fold higher than that of A group) could decrease the mRNA level of CCK gene. Compared with FT3, FT4 might have more important role on the regulation of CCK mRNA induced by excess of iodine.

[Changes of nuclear factor-kappaB and intercellular adhesion molecule-1 in endothelial cells exposed to various intermittent hypoxia].

OBJECTIVE: To construct a novel in vitro endothelial cell system to explore the changes of nuclear factor-kappaB (NF-kappaB) and intercellular adhesion molecule-1 (ICAM-1) levels after exposure to various intermittent hypoxia (IH) and re-oxygenation, an IH/reoxygenation (ROX) model. METHODS: We developed a gas control delivery system that permitted the exposure of ECV304 cell cultures, immortalized endothelial cell strain cultures of human umbilical vein endothelial cells (HUVEC), to IH/ROX cycles, simulating the pattern of hypoxic episodes seen in recurrent apnea. Cell samples were divided into the following groups according to IH duration/ROX duration. Group A (Intermittent Normoxia Group): 21% O(2) 15 s/21% O(2) 3 min 45 s; Group B (Standard Culture Group): no exposure; Group C: 1.5% O(2) 15 s/21% O(2) 3 min 45 s; Group D: 10% O(2) 15 s/21% O(2) 3 min 45 s; Fixed IH protocol as 1.5% O(2) 15s and ROX extent to 21% O(2), IH/ROX frequencies varied as 12 (Group C), 9.23 (Group E), 6.32 (Group F), 20 (Group G) and 40 (Group H) episodes per hour; Group I: 1.5% O(2) 30 s/21% O(2) 3 min 45 s; and after the exposure of Group C, the cell cultures were exposed to standard incubation device for 60 min (Group J) and 120 min (Group K). Prepared cell lysates and cell monolayers were analyzed for NF-kappaB levels and ICAM-1 levels in this IH model with enzyme-linked immunosorbent assay (ELISA) and cellular surface ELISA, and the cell total protein levels were measured with the method of bicinchoninic acid for standardization. SPSS 11.5 software package was used for statistical analysis. RESULTS: NF-kappaB and ICAM-1 levels in Group C were (0.82 +/- 0.28) and (1562 +/- 56) pg/ml, and those in Group A were (0.37 +/- 0.07) and (768 +/- 80) pg/ml, which showed statistical significance as compared with Group C (D = 225.00, 176.04, P < 0.01, < 0.05, respectively). Their levels in Group D were (0.66 +/- 0.22) and (1113 +/- 76) pg/ml, which were also significantly lower than Group C (U = 25.00, 0.00, all P < 0.01). NF-kappaB and ICAM-1 levels in Group I were (0.45 +/- 0.16) and (1155 +/- 19) pg/ml, which were statistically significant compared with Group C (U = 27.00, 0.00, all P < 0.01). In the same time, IH group had the relatively highest NF-kappaB and ICAM-1 levels amongst groups C, E, F, G and H. Which had different IH frequencies (chi(2) = 35.63, 56.89, all P < 0.01). NF-kappaB levels in Group J [(0.6233 +/- 0.0534)] did not differ significantly from Group C (D = 36.00, P > 0.05) and NF-kappaB levels in Group K [(0.3050 +/- 0.0013)] were lower than Group C (D = 234.00, P < 0.01). CONCLUSIONS: Our data indicated a selective and dose-dependent activation of inflammatory pathways on ECV304 cells by IH/ROX cycles with moderate frequencies, and a long time was needed for the cell rehabilitation from IH/ROX exposure.

[Interleukin-6 and tumor necrosis factor-alpha levels of endothelial cells in different hypoxia modes: in vitro experiment].

OBJECTIVE: To investigate the damage of different patterns of intermittent hypoxia (IH) and continuous hypoxia (CH) on endothelial cells. METHODS: Human umbilical vein endothelial cells of the line ECV304 were cultured in a program-controlled gas delivery system newly developed and divided into 8 groups to undergo different IH/reoxygenation (ROX) cycles so as to simulate the patterns of hypoxic episode seen in recurrent apnea and chronic obstructive pulmonary disease: intermittent normoxia (IN) group (exposed to 21% O2 15 s/21% O2 225 s for 60 cycles), IH group (exposed to 1.5% O2 15 s/21% O2 225 s for 30 or 60 cycles), IH hypercapnia group (exposed to 1.5% O2 and 20% CO2 15 s/21% O2 and 5% CO2 225 s, for 60 cycles), continuous hypoxia (CH group, exposed to 1.5% or 10% O2 for 15, 30 or 60 min), CH hypercapnia group (exposed to 10% O2 and 10% CO2 for 15, 30 or 60 min), CH added to IH group (exposed to 1.5% O2 15 s/10% O2 225 s for 60 cycles), different intermittent hypoxia extent group (exposed to 1.5% or 10% O2 15 s/21% O2 225 s for 60 cycles), different intermittent hypoxia frequency group (exposed to 1.5% O2 15 s/21% O2 225 s 315 s, 495 s or 105 s for 60 cycles), and different intermittent hypoxia duration group (exposed to 1.5% O2 15 s or 30 s/21% O2 225 s for 60 cycles). Then ELISA was conducted to examine the levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFalpha) Bicinchoninic acid method was used to standardize the cell total protein level. RESULTS: The levels of IL-6 and TNFalpha levels in the IH group were (770.40 +/- 21.60) and (126.93 +/- 2.58) pg.ml(-1).100 mg protein(-1) respectively, both significantly higher than those in the IN group [(374.06 +/- 38.10) and (31.96 +/- 13.64) pg.ml(-1).100 mg protein(-1) respectively, U = 0.000, P = 0.002], but significantly lower than those in the IH hypercapnia group [(829.27 +/- 7.16) and (78.77 +/- 4.00) pg.ml(-1).100 mg protein(-1) respectively, U = 0.000, P = 0.002]. The IL-6 levels of the CH hypercapnia 15, 30, and 60 min subgroups were all significantly higher than those of the corresponding CH subgroup (U = 0.000, P = 0.002). The IL-6 and TNFalpha levels of the CH added to IH group were (536.74 +/- 14.97) and (51.10 +/- 6.80) pg.ml(-1).100 mg protein(-1) respectively, both were significantly higher than those of the IN group, but significantly lower than those of the IH group (chi(2) = 23.4, P < 0.05). The levels of IL-6 and TNFalpha increased along with the increase of the IH degree (chi(2) = 23.4, P < 0.05). The level changes of IL-6 and TNFalpha of the groups with different intermittent hypoxia frequency and with different intermittent hypoxia duration were complicated. CONCLUSION: IH and CH significantly damage the endothelial cells dose-dependently, especially combined with hypercapnia. In IH/ROX, the inflammatory damage comes from ROX phase but not IH phase. Hypoxia duration and hypoxia frequency are also important parameters in the activation of inflammation.

[DNA typing of HLA-I and II antigens with medium resolution method by DNA chip technique].

OBJECTIVE: To establish a DNA typing method for the HLA-I and II antigens in the Chinese of Han Nationality in Northern China with medium resolution method by DNA chip technique. METHODS: Corresponding primers for the sense exon fragments of HLA-A, HLA-B, HLA-DR, HLA-DQB, and HLA-DQA were designed. A DNA typing chip was made with specific medium resolution typing probes designed according to the gene frequency of HLA-I and II alleles among the Chinese of Han nationality in Northern China. Unsymmetrical PCR was used to amplify the HLA-I and II exon2 and exon3 in 30 samples from the Chinese of Han nationality in Northern China, and then the PCR products were labeled and hybridized with the probes on the chip. The typing of HLA-I and II was certified by scanning the hybridized products and analyzing them with a set of computer software. RESULTS: HLA-I and II alleles were successfully typed in 30 clinical samples. The h probes with medium resolution were able to discern 42 HLA-I and II alleles accurately. By using this chip 30 HLA-I and II alleles were distinguished and 6 new specific alleles were found. CONCLUSION: DNA typing of HLA-I and II by chip has been proven to be a high-resolution and high-specificity method. It is able to check out new alleles that can not be distinguished by other methods with the same resolution, and it is more intuitive and more suitable for clinical application.

Pre-deliver chitosanase to cells: a novel strategy to improve gene expression by endocellular degradation-induced vector unpacking.

A radio-labeled plasmid pTracer/Bsd/LacZ containing LacZ reporter gene was complexed with different molecular weights of chitosans (CS). Mouse myoblast cell line C2C12 was transfected by these chitosan-plasmid DNA complexes, and lipofectamine 2000 was used as control. Forty-eight hours after transfection, the activity of beta-galactosidase and radioactive count of cell lysis were determined. It was found that chitosan, especially low molecular weight species, had a surprising ability to deliver DNA into cells, since the radioactive count of cells transfected by chitosan-DNA complexes was even two times that of cells transfected by lipofectamine 2000. But the beta-galactosidase activity of chitosan/DNA complexes was much lower compared to that of lipofectamine 2000. Chitosanase which could degrade chitosan in specific mode was transported into C2C12 cells by osmotic lysis prior to gene delivery. Then these chitosanase-modified cells were transfected by CS-DNA complexes. The results indicated that beta-galactosidase activity in these cells increased markedly to 425.4 +/- 45.1 U/mg protein, nearly two-fold as that of cells transfected by liposome. This transfection protocol was also applied to 3T3 mouse fibroblast, 2T3 mouse osteoblast and MG63 human osteosarcoma cell lines, and an increased gene expression level was observed without exception. It is thought that the incorporated chitosanase could aid in chitosan degradation, which would promote gene unpacking, consequently increasing gene expression.

[Cloning and eukaryotic expression of wild type and truncated mouse ciliary neurotrophic factor gene].

OBJECTIVE: To clone and eukaryotic express wild type and truncated mouse ciliary neurotrophic factor (CNTF) gene, and to observe the biological effect of two types of CNTF gene expressing in ARPE-19 cells. METHODS: RT-PCR was used to amplify the cDNA of CNTF gene, and truncated CNTF cDNA was obtained by site-directed mutagenesis. The two types of CNTF gene were cloned into plasmid pTracer-CMV and transfected to ARPE-19 cells. Dot blotting was used to detect the expression of CNTF. MTT and flow cytometry apoptosis assay were performed to observe the biological effect of CNTF expressing in ARPE-19 cells. RESULTS: Wild type and truncated CNTF gene were amplified by RT-PCR, and their eukaryotic expression plasmids were successfully constructed. After ARPE-19 cells transfected with two types of recombinant plasmids, the CNTF were detected in the supernatant of cells culture. MTT result shows that two types of CNTF have no proliferation promoting effect to ARPE-19 cells, and quantitive apoptosis assay implicated that CNTF could partially suppress the apoptosis that induced by the cells culturing with serum free culture. CONCLUSION: Expression of two types of CNTF in ARPE-19 cells gets prepared for gene therapy research of retinitis pigmentosa.

[Cloning and expression of an Aspergillus fumigatus chitosanase gene].

According to published DNA sequence of Aspergillus fumigatus chitosanase(Csn) gene, 8 long single DNA strands each about 100bp and 4 DNA primers were designed and synthesised. By PCR, 8 DNA strands were connected into a complete chitosanase gene of 624bp. This chitosanase gene was not identical with its wild type, some point mutations were introduced into its DNA sequence by special design of those 8 DNA strands. These mutaions did not change amino acid composition of the chitosanase, however, the codens were changed into E. coli favorites. The Csn gene was cloned into plasmid pGEM-Teasy and verified by DNA sequence analysis. Thereafter, Csn gene was subcloned into a fusion-protein expressing vector pGEX-3X. Recombinant plasmid pGEX-Csn was transformed into E. coli DH5alpha and the transformant was induced expressing with 0.5 mmol/L IPTG. Expressing product was analyzed by SDS-PAGE, fusion protein GST-Csn was purified by affinity chromatography. By factor X a digestion GST-Csn was cleaved and GST was taken out by another chromatography. The biological activity of recombinant chitosanase(rCsn) was also detected, as a result the recombinant Csn had a strong ability of degrading chitosan, which was much higher than lysozyme. Its chitosan-degradation activity could be influenced by pH and temperature.

Expression, purification and bioactivity characterization of extracellular domain of murine osteoprotegerin ligand.

Osteoprotegerin ligand (OPGL) is a key regulator of formation and activation of osteoclasts. In the present study, the cDNA encoding the extracellular domain of murine OPGL (sOPGL) was synthesized by RT-PCR and cloned into fusion expression vector pET-42a(+) in a certain strategy on purpose that the fusion tag could be completely removed by factor Xa from the expressed fusion protein without any vector-encoded sequence left. Induced with IPTG, the recombinant E. Coli cells produced a 47 kD protein in high level that could be recognized, through Western blotting analysis, by the antibody against OPGL. The expressed products were purified through Glutathione-sepharose 4B affinity chromatography. Along with the fusion molecule, a protein about 30 kD was also specifically bound to the resin. The 30 kD molecule could be recognized by polyclonal antibody against GST-IGF-1, but not by antibody against OPGL. It suggested that the 30 kD molecule was derived from the degradation of the fusion protein. After the cleavage with factor Xa and further purification, the fusion tag was removed and the recombinant sOPGL was obtained. Finally, we confirmed that the recombinant sOPGL could promote osteoclast formation from mouse bone marrow cells in a dose dependent manner.

N-alkylated chitosan as a potential nonviral vector for gene transfection.

Alkylated chitosans (ACSs) were prepared by modifying chitosan (CS) with alkyl bromide. The self-aggregation of ACSs in acetic acid solution was characterized by fluorescence spectroscopy and dynamic light scattering method. The results indicate that introducing alkyl side chains leads to the self-aggregation of ACSs, and CS with a 99% deacetylation degree shows no aggregation due to the electrostatic repulsion. The electrophoresis experiment demonstrates that the complex between CS and DNA was formed at a charge ratio (+/-) of 1/1; ACS/DNA complexes were formed at a lower charge ratio (+/-) of 1/4. A small amount of alkylated chitosans play the same shielding role as chitosan in protecting DNA from DNase hydrolysis. Differential scanning calorimetry (DSC) and atomic force microscopy (AFM) were employed separately to investigate the thermodynamic behavior of dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/CS and DPPC/ACS mixtures and the variation in topological structure of DPPC membrane induced by CS and ACS. It is shown that CS and ACS can cause the fusion of DPPC multilamellar vesicles as well as membrane destabilization. In contrast, the perturbation effect induced by ACS is more evident due to the hydrophobic interaction. CS and ACS were used to transfer plasmid-encoding CAT into C(2)C(12) cell lines. Upon elongating the alkyl side chain, the transfection efficiency is increased and levels off after the number of carbons in the side chain exceeds 8. It is proposed that the higher transfection efficiency of ACS is attributed to the increasing entry into cells facilitated by hydrophobic interactions and easier unpacking of DNA from ACS carriers due to the weakening of electrostatic attractions between DNA and ACS.

[The construction of yak liver cDNA library].

Yak is a very useful animal. The cDNA library of yak liver was constructed, which made a preparation for further cloning and expressing of wanted genes.mRNA from yak liver was extracted and purified, and cDNA was obtained by reverse transcription,and then cDNA library was constructed using plasmid pSPORT1 as the vector. The volume of the library was 1 x 10(6) transformants/microg cDNA and the rate of recombination was 93%. The results indicated that the cDNA library had enough volume for selecting wanted genes and made the basic of studying yak's genetic background.

[The cloning and expression of rat insulin-like growth factor I gene].

In this study an exons-connecting technique was used to amplify the complete DNA sequence encoding the mature peptide of IGF-I. Two pairs of primers were synthesized, primer a (Pa) and primer b (Pb) were used to amplify exon 2 coding fragment while primer c (Pc) and primer d (Pd) for amplifying exon 3 coding fragment. Pb was 40 bp, 18 bp at its 5' end was same with the anti-sense of exon 3's 5' end. Pc consisted of 41 bp with 22 bp at its 5' end consistent with the sense of the exon 2's 3' end. Genome DNA was extracted from rat liver. Using rat genome DNA as template PCR was performed with Pa, Pb and Pc, Pd as primers respectively. Two kinds of PCR products were obtained. One was 90 bp corresponding with the exon 2, another was 160 bp corresponding with the exon 3. Another PCR was done with these two PCR products used as not only template but also primers for each other. A 210 bp DNA fragment was produced, which encodes the mature peptide of rat IGF-I. Firstly the gene was cloned into plasmid pUC18. Then the recombinant plasmid pUC-IGF-I was digested with restriction endonuclease BamHI and EcoRI, plasmid pGEX-3X was digested with the same enzyme. IGF-I gene was linked into pGEX-3X and expressing plasmid pGEX-IGF-I was constructed. Plasmid pGEX-IGF-I was transformed into E. coli DH5 alpha and induced to express by IPTG. Expressed protein was analysized by SDS-PAGE. A fusion protein of GST-IGFI about 32.5 kDa could be observed. Western blot was performed with goat anti-human IGF-I IgG as primary antibody and donkey anti-goat IgG HRP as secondary antibody. Its result confirmed that the fusion protein really containing IGF-I. GST-IGFI was purified by affinity-chromatography and carrier-protein GST was cut off by Factor Xa. The bioactivity of purified IGF-I was detected with cultured NIH3T3 cell. The recombinant rat IGF-I can promote cell proliferation, shown by the elevation of 3H-TdR incorporation.