Functional analysis of hepatitis B virus immune escape mutants with insertion mutations in the surface antigen / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To evaluate the influence of insertion mutations occurring in the hydrophobic region, between amino acids 114 and 115, of the hepatitis B surface antigen (HBsAg) on viral antigenicity and replication.</p><p><b>METHODS</b>Hepatitis B virus (HBV) DNA was obtained from patients with HBsAg-positive chronic hepatitis B (CHB) infection and subjected to sequence analysis and comparison to GenBank reference sequences for HBV genotype B (AB073826) and genotype C (AF286594). Insertion mutations detected in the HBsAg region were used to make recombinant expression plasmids via site-directed mutagenesis. After transfecting the recombinant HBsAg into Huh7 cells, the mutants' effects on viral antigenicity and replication were evaluated by chemiluminescence microparticle immunoassay (CMIA) and Southern blot hybridization, respectively. The viral antigenicity of each mutant was predicted by bioinformatic analysis, using the Jameson-Wolf method to predict the antigenic index, the Hopp-Woods method to predict hydrophilicity, the Emini method to predict the probability of a region lying of the protein's surface, and the Karplus-Schulz method to predict the flexibility of the protein backbone.</p><p><b>RESULTS</b>Two CHB patients harbored HBV with insertion mutations in HBsAg: one with two (NT) and one with three (NTT) inserted amino acids between 114 and 115. The NTT recombinant HBsAg mutant showed no impact on viral replication and reacted weakly with anti-HBs in CMIA (P = 0.02). The antigen indices for the insertion of NTT were 1.00, -0.16, and 0.18, and insertion of the three amino acids affected the index values of five proximal amino acid sites (with an average increase of 0.13). The hydrophilic indices for the insertion of NTT were 0.2, -0.4, and -0.4, with no significant effect on the proximal amino acids. The insertion of the three amino acids changed both the surface probability (range: -0.55 to 2.97; affecting eight proximal amino acids) and the flexibility (range: -0.01 to 1.1; affecting five proximal amino acids).</p><p><b>CONCLUSION</b>The NTT three amino acids insertion in the HBsAg open reading frame, between 114 and 115 of the wild-type sequence, detected in a CHB patient may play a role in HBV immune escape without influencing the viral replicative capacity.</p>

Effect of glucagon-like peptide-1 on hypoxia-reoxygenation induced injury in neonatal rat cardiomyocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the effect of glucagon-like peptide-1 (GLP-1) on hypoxia-reoxygenation (H/R) induced injury in neonatal rat cardiomyocytes.</p><p><b>METHODS</b>Cultured neonatal rat cardiomyocytes were randomly divided into seven groups: normal control group, H/R group, GLP-1 + H/R group, GLP-1 + H/R + UO126 group, GLP-1 + H/R + LY294002 group, H/R + UO126 group, H/R + LY294002 group. LDH activity, apoptosis rate of cardiomyocytes, Caspase-3 activity were detected.</p><p><b>RESULTS</b>Compared with normal control group, the activity of LDH, cardiomyocyte apoptosis rate, Caspase-3 activity were all significantly increased in H/R group (all P < 0.01). However, compared with H/R group, these changes were significantly attenuated in GLP-1 + H/R group [the activity of LDH (128.47 +/- 7.96) U/L vs. (223.96 +/- 22.10) U/L, P < 0.01, and cardiomyocyte apoptosis rate (2.84 +/- 2.56)% vs. (12.58 +/- 6.69)%, P < 0.01, and Caspase-3 activity (36,809 +/- 4750) RLU vs. (57,602 +/- 9161) RLU, P < 0.01], while LY294002 (PI3K inhibitor) and UO126 (MAPK inhibitor) could block the effects of GLP-1 in cardiomyocytes underwent H/R injury.</p><p><b>CONCLUSIONS</b>GLP-1 could protect H/R injury mainly by inhibiting cardiomyocytes apoptosis via activating PI3K/Akt and MAPK signaling pathway.</p>

Mutation patterns in the RT region of hepatitis B virus P gene in patients treated with nucleoside/nucleotide analogs / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To analyze mutation patterns in the RT region of hepatitis B virus (HBV) P gene in patients treated with nucleoside or nucleotide analogs.</p><p><b>METHODS</b>Viral DNA was extracted from 227 serum samples of chronic hepatitis B patients from September, 2005 to March, 2007. The RT region of HBV P gene was PCR-amplified and sequenced.</p><p><b>RESULTS</b>Known resistant mutations were found in 111 cases (48.9%) among 227 samples, 75 cases with clear therapy history. Novel mutations, including A222T, L229V and S256C, were also found. The incidence of multi-drug resistance in patients sequentially treated with lamivudine and adefovir was 25% (4/16), and none of the patients treated with lamivudine plus adefovir in combination shown multi-drug resistance.</p><p><b>CONCLUSION</b>The patterns of mutation is complex in nucleotide analogue treated patients. Switching to adefovir in lamivudine resistant patients may lead to multi-drug resistance. Novel mutations identified in this study need further investigation.</p>

Attenuation of myocardial apoptosis by alpha-lipoic acid through suppression of mitochondrial oxidative stress to reduce diabetic cardiomyopathy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cardiac failure is a leading cause of the mortality of diabetic patients. In part this is due to a specific cardiomyopathy, referred to as diabetic cardiomyopathy. Oxidative stress is widely considered to be one of the major factors underlying the pathogenesis of the disease. This study aimed to test whether the antioxidant alpha-lipoic acid (alpha-LA) could attenuate mitochondrion-dependent myocardial apoptosis through suppression of mitochondrial oxidative stress to reduce diabetic cardiomyopathy.</p><p><b>METHODS</b>A rat model of diabetes was induced by a single tail intravenous injection of streptozotocin (STZ) 45 mg/kg. Experimental animals were randomly assigned to 3 groups: normal control (NC), diabetes (DM) and DM treated with alpha-LA (alpha-LA). The latter group was administered with alpha-LA (100 mg/kg ip per day), the remainder received the same volume vehicle. At weeks 4, 8, and 12 after the onset of diabetes, cardiac apoptosis was examined by TUNEL assay. Cardiomyopathy was evaluated by assessment of cardiac structure and function. Oxidative damage was evaluated by the content of malondialdehyde (MDA), reduced glutathione (GSH) and the activity of manganese superoxide diamutase (Mn-SOD) in the myocardial mitochondria. Expression of caspase-9 and caspase-3 proteins was determined by immunohistochemistry and mitochondrial cytochrome c release was detected by Western blotting.</p><p><b>RESULTS</b>At 4, 8, and 12 weeks after the onset of diabetes, significant reductions in TUNEL-positive cells, caspase-9,-3 expression, and mitochondrial cytochrome c release were observed in the alpha-LA group compared to the DM group. In the DM group, the content of MDA in the myocardial mitochondria was significantly increased, and there was a decrease in both the mitochondrial GSH content and the activities of Mn-SOD. They were significantly improved by alpha-LA treatment. HE staining displayed structural abnormalities in diabetic hearts, while alpha-LA reversed this structural derangement. The index of cardiac function (+/-dp/dtmax) in the diabetes group was aggravated progressively from 4 weeks to 12 weeks, but alpha-LA delayed deterioration of cardiac function (P < 0.05).</p><p><b>CONCLUSIONS</b>Our findings indicate that the antioxidant alpha-LA can effectively attenuate mitochondria-dependent cardiac apoptosis and exert a protective role against the development of diabetic cardiomyopathy. The ability of alpha-LA to suppress mitochondrial oxidative damage is concomitant with an enhancement of Mn-SOD activity and an increase in the GSH content of myocardial mitochondria.</p>

P-glycoprotein regulating biphasic insulin secretion in rat pancreatic beta cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>A 65-kD mdr1 (multi-drug resistance protein 1, P-glycoprotein)-like protein has been suggested to be the regulatory protein to the chloride channel protein 3 (ClC-3) mediating insulin granules acidification and release in mouse pancreatic beta cells. But the protein has not been deeply investigated. In this study, we identified existence of the 65-kda protein in rat islets and preliminarily explored its biological functions.</p><p><b>METHODS</b>Total RNAs of rat kidneys served as positive controls, and pancreas, islets and INS-1 cells were extracted for reverse-transcript PCR (RT-PCR), respectively. The cDNAs were run with specific primers selected from the mRNA of abcb1b encoding P-glycoprotein. All PCR products were visualized in agarose gel electrophoresis and sequenced. Homogenates of rat islets and INS-1 cells were applied to SDS-PAGE. P-glycoprotein was detected by a specific monoclonal antibody, C219. Biphasic insulin release was measured in static incubations of rat islets with radioimmunology assay.</p><p><b>RESULTS</b>Compared with positive control, expression of the P-glycoprotein mRNA segments were detected in the islets, INS-1 cells and pancreas. Sequence analysis confirmed that the PCR products were matched with mRNA of P-glycoprotein. A 65-kda protein was recognized by the antibody in the islets homogenate but not in that of INS-1 cells in Western-blotting. Instead, the homogenate of INS-1 cells contained a 160-kda protein recognized by the antibody. Insulin secretion of rat islets were stimulated by high glucose (16.7 mmol/L), and showed biphasic curve during 60-minute incubation. After co-incubation with cyclosporine A (CsA), specific inhibitor to P-glycoprotein, the second phase of insulin secretion was reduced significantly while the first phase was not influenced.</p><p><b>CONCLUSIONS</b>The 65-kda protein expressed in rat islets is most likely a mini-P-glycoprotein. It may play a key role regulating biphasic insulin release.</p>

Role of S6K1 in the induction of SREBP1c in mouse hepatic cell by high glucose stimulation / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To study the role of S6K1 in the induction of SREBP1c in mouse hepatic cell by high glucose stimulation.</p><p><b>METHODS</b>S6K1 shRNA recombinant adenovirus (S6K1Ax) was injected into tail vein of db/db mice and then hepatic triglycerol content was analyzed. Liver specimen were stained with HE. After transfection with S6K1Ax or pU6Ax, mouse hepatic AML12 cells were treated with high glucose, insulin or glucose and insulin, the expression of mSREBP1c was detected by RT-PCR. S6K1 protein was detected by Western blot.</p><p><b>RESULTS</b>Hepatic S6K1 protein in db/db mice was inhibited a week after S6K1Ax injection. Compared with the control group, hepatic triglycerol content of S6K1Ax group was decreased (0.65+/-0.02) mmol/L vs (0.56+/-0.01) mmol/L (t = 4.312, P less than 0.01), hepatocyte fat droplet and vaculor generation were also decreased, fatty liver was improved. The mSREBP1c expression in S6K1Ax transfected cells was lower than that in the control cells (0.03+/-0.01 vs 0.06+/-0.01, t = 5.624, P less than 0.01). Compared with the basal state, SREBP1c expression of both groups was increased on the insulin stimulation, S6K1Ax group was 0.06+/-0.02 (t = 8.452, P less than 0.01) and control group was 0.08+/-0.02 (t = 3.591, P less than 0.05). There is no difference between control and S6K1Ax group by glucose addition (P more than 0.05).</p><p><b>CONCLUSION</b>S6K1 acts on fatty synthesis by regulating mSREBP1c expression.</p>

Molecular mechanism of limbs' postischemic revascularization improved by perindopril in diabetic rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Currently, there are still divergent opinions about the mechanisms of the impaired neovascularization in diabetic subjects. Due to the remarkable therapeutic effect of angiotensin-converting enzyme inhibititors (ACEIs) on the reduction of blood pressure and the protection of target organs, the clinical application of this kind of drugs is very widespread. However, it is still not clear about the role and related molecular pathway of this kind of drugs in the limbs' postischemic revascularization. It is of major therapeutic importance to resolve these questions. This study aimed to investigate the reasons of the impaired angiogenesis in the hind limbs of rats with diabetic ischemia, the role and related molecular mechanisms of ACEI in postischemic revascularization.</p><p><b>METHODS</b>Hind limbs ischemia was induced in diabetic rats by right femoral artery excision. Diabetic rats were randomly allocated to one of the following treatments for 4 weeks: ACEI by perindopril; perindopril in combination with a nitric oxide synthase (NOS) inhibitor; perindopril in combination with bradykinin (BK)-B1 receptor (B1R) antagonist or saline. The differences of angiogenesis, the mRNA and protein expression of endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF) and basic fibroblast (bFGF), constitutive nitric oxide synthase (cNOS) activity and nitric oxide (NO) content were observed after treatment.</p><p><b>RESULTS</b>In non-ischemic hind limbs, no significant changes in capillary density, or the mRNA and protein expression of eNOS, VEGF and bFGF, or the NO content and the cNOS activity were observed among all groups. On the contrary, in ischemic hind limbs, the capillary density in diabetic rats decreased by 27% when compared with the control rats, so did the mRNA and protein expression of eNOS, VEGF and bFGF, or the NO content and the cNOS activity (P < 0.05). The capillary density was increased by 1.65-fold in the perindopril treatment group in reference to untreated diabetic rats. Moreover, administration of perindopril enhanced the mRNA expression of eNOS, VEGF, and bFGF by 1.45-, 1.44-, and 1.33-fold, increased the protein content of the above indices by 1.55-, 1.30- and 1.50-fold compared with the untreated diabetic rats respectively. Perindopril also increased NO content and cNOS activity to 1.33- and 1.38-fold of that in untreated diabetic rats. The combination of BK-B1R antagonist significantly decreased the above indices (P < 0.05). In contrast, the combination of NOS inhibitor decreased the expression of eNOS and bFGF, the NO content and the cNOS activity, while the expression of VEGF did not change.</p><p><b>CONCLUSIONS</b>Diabetes mellitus reduces the neovascularization, related growth factors expression and activity in the diabetic rat ischemic legs model. Treatment of perindopril improves postischemic revascularization. This effect is mediated, at least in part, by the BK-B1R-related pathway, and the activation of VEGF/eNOS/bFGF signals may be involved in the pro-angiogenic effect.</p>

Effects and mechanism of glucagon-like peptide-1 on injury of rats cardiomyocytes induced by hypoxia-reoxygenation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Although the insulinotropic role of glucagon-like peptide-1 (GLP-1) in type 2 diabetes mellitus has been substantiated, its role in cardioprotection remains largely unknown. This study aimed to determine the effects of GLP-1 on injury of rats cardiac myocytes induced by hypoxia-reoxygenation (H/R) and the possible mechanisms.</p><p><b>METHODS</b>The cultured neonatal rats cardiac myocytes were randomly divided into seven groups: the normal control group, the H/R group, the GLP-1 + H/R group, the GLP-1 + H/R + UO126 (the p42/44 mitogen-activated protein kinase (MAPK) inhibitor) group, the GLP-1 + H/R + LY294002 (phosphatidylinositol 3-kinase (PI3K) inhibitor) group, the H/R + UO126 group, and the H/R + LY294002 group. The lactate dehydrogenase (LDH) activity, apoptosis rate of cardiac myocytes, and caspase-3 activity were detected after the injury of H/R.</p><p><b>RESULTS</b>Compared with the normal control group, the activity of LDH, cardiac myocyte apoptosis rate, and caspase-3 activity all increased significantly in the H/R group (P < 0.01). Compared with the H/R group, these three indices all decreased in the H/R + GLP-1 group (P < 0.01). However, the changes of LDH activity, apoptosis rate, and caspase-3 activity were inhibited by LY294002 and UO126 respectively.</p><p><b>CONCLUSIONS</b>GLP-1 can directly act on cardiac myocytes and protect them from H/R injury mainly by inhibiting their apoptosis. Its mechanism may be through the PI3K-Akt pathway and the MAPK signaling pathway.</p>

Mitochondrial gene mutations and type 2 diabetes in Chinese families / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Numerous mitochondrial DNA mutations are significantly correlated with development of diabetes. This study investigated mitochondrial gene, point mutations in patients with type 2 diabetes and their families.</p><p><b>METHODS</b>Unrelated patients with type 2 diabetes (n = 826) were randomly recruited; unrelated and nondiabetic subjects (n = 637) served as controls. The clinical and biochemical data of the participants were collected. Total genome was extracted from peripheral leucocytes. Polymerase chain reaction, restriction fragment length polymorphism (PCR-RFLP) and cloning techniques were used to screen mitochondrial genes including np3316, np3394 and np3426 in the ND1 region and np3243 in the tRNA(Leu(UUR)).</p><p><b>RESULTS</b>In 39 diabetics with one or more mitochondrial gene point mutations, the prevalence (4.7%, 39/826) of mtDNA mutations was higher than that (0.7%, 5/637) in the controls. The identical mutation was found in 23 of 43 tested members from three pedigrees. Affected family members presented with variable clinical features ranging from normal glucose tolerance to impaired glucose tolerance (IGT) (n = 2), impaired fasting glucose (IFG) (n = 1) to type 2 diabetes (n = 13) with 3 family members suffering from hearing loss.</p><p><b>CONCLUSIONS</b>Type 2 diabetes in China is associated with several mitochondrial gene mutations. Aged patients with diabetic family history had a higher prevalence of mutation and various clinical pictures. Mitochondrial gene mutation might be one of the genetic factors contributing to diabetic familial clustering.</p>

Prevalence and risk factors of peripheral arterial disease in diabetic patients over 50 years old in China / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the prevalence of peripheral arterial disease (PAD) in China type 2 diabetic patients and to demonstrate the relationships between putative risk factors and PAD.</p><p><b>METHODS</b>In total 1,397 type 2 diabetic patients aged 50 years and older were enrolled and determined ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) in 15 Class III Grade A hospitals in 7 major cities of China.</p><p><b>RESULTS</b>Mean patient age was 63.7 +/- 8.2 years and mean duration of diabetes mellitus was 9.39 +/- 7.4 years. Two hundreds and seventy-two (19.47%) patients were diagnosed as PAD by ABI < 0.9, 122 (18.37%) in male and 150 (20.46%) in female. PAD patients had a significantly longer duration of diabetes mellitus, higher hemoglobin A1c, and a significantly lower mean body mass index than non-PAD ones. Aging, smoking, and systolic blood pressure were found to be positively related with the prevalence of PAD. In terms of lipid profiles, no variable was found to relate with PAD. Notably, baPWV showed as the same significant guiding index for PAD, almost matched with ABI.</p><p><b>CONCLUSIONS</b>PAD is a common complication in China type 2 diabetic patients. Therefore, PAD screening and treatment should be emphasized for diabetic patients with high risk factors.</p>

Study on the mitochondrial DNA mutations in patients with early-onset diabetes mellitus / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of mitochondrial DNA (mtDNA) mutations in patients with early-onset diabetes in Tianjin, and to explore the relationship between mtDNA mutations and diabetes.</p><p><b>METHODS</b>348 non-related patients whose age at onset of diabetes was less than 45 years were randomly recruited, and 207 non-related and non-diabetic subjects were enrolled as controls. All their clinical and biochemical data were collected. Total genome was extracted conventionally from the participants' peripheral leucocytes, and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and cloning techniques were applied to the screening of mtDNA mutations (including the 3316, 3394 and 3426 in ND1 region, 12026 in ND4 region, and tRNA [Leu(UUR)] 3243 A-->G mutation).</p><p><b>RESULTS</b>The authors found 17 diabetics harboring the 12026 A-->G mutation in ND4 region (4.9%), 10 diabetics with mutations in ND1 region (including 5 diabetics with the 3394 T-->C mutation, 4 diabetics with 3316 G-->A mutation, one with 3426 A-->G mutation), and only two with the known 3243 A-->G mutation (0.6%). On the contrary, one control subject with the 3316 G-->A mutation, two with 3394 T-->C mutation and four with 12026 A-->G mutation were found. The prevalence of mtDNA mutations in the patient group is significantly higher than that in the control group (3.3%) (P<0.05).</p><p><b>CONCLUSION</b>The above findings suggest that mtDNA mutation may be implicated in the pathogenesis of the examined diabetes.</p>

Relationship between mutations of mitochondrial DNA ND1 gene and type 2 diabetes / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Recent studies have indicated that many mutations in mitochondrial (mt) DNA NDI gene region are related to diabetes mellitus. In this study we explored the relationship between various mtDNA ND1 gene mutations and type 2 diabetes mellitus (DM) among Chinese.</p><p><b>METHODS</b>Using PCR restriction fragment length polymorphism (PCR-RFLP) analysis and gene sequencing, 4 spots of mtDNA (nt3243, nt3316, nt3394, nt3426) were screened in 478 diabetics and 430 non-diabetic subjects.</p><p><b>RESULTS</b>In diabetic group, there were 13 carriers (2.72%) of 3316 G-->A mutation,12 (2.51%) of 3394 T-->C mutation and 2 (0.42%) of 3426A-->G mutation. In controls, only 3394 T-->C mutation was observed in 2 subjects (0.47%). There was significant difference in the frequency of 3316 and 3394 mutation between two groups (P < 0.05, respectively). More subjects with mitochondrial DNA ND1 gene mutations had DM family history and greater tendency of maternal inheritance when compared to those patients without mutation in diabetic group (P < 0.01). A 3426 mutation diabetic pedigree was studied, and we found 12 maternal members in the family had the same mutation.</p><p><b>CONCLUSION</b>mtDNA ND1 gene mutations at nt3316 (G-->A), nt3394 (T-->C) and 3426 (A-->G) might contribute to the pathogenesis of DM with other genetic factors and environment factors.</p>

Study on a new point mutation of nt3426 A --> G of mitochondrial DNA in a diabetes mellitus family / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To elucidate the relationship between point mutations of nt3243A --> G, nt3426 A --> G of mitochondrial DNA and type 2 diabetes mellitus(DM).</p><p><b>METHODS</b>Two hundred patients with type 2 DM and 180 controls with normal glucose tolerance and absence of DM family history were included. The mutations were determined by PCR-restriction fragment length polymorphism.</p><p><b>RESULTS</b>The point mutation nt3426A --> G of mitochondrial DNA ND1 was found in 2 of the patients with type 2 DM (1.0%) but in none of the controls (0). The incidence of this mutation showed no significant difference between the two groups(P>0.05). And none was found to have the mutation of nt3243 --> G.</p><p><b>CONCLUSION</b>The point mutation nt3426 A --> G of mitochondrial DNA ND1 may not be an independent factor to cause type 2 DM.</p>