Xiaobo Yu

Involvement of Th17 and Th1 Effector Responses in Patients with Hepatitis B

BackgroundLocal production of cytokines within the liver may play a pivotal role in the regulation of pathophysiological processes during inflammation. CD4+ T cells are regarded as the most prolific cytokine producers. The purpose of this study was to quantify intrahepatic expression of Th1, Th2, Th17, and Treg-associated cytokines or transcription factors in patients with acute hepatitis B or chronic hepatitis B (CHB) and to analyze their relative roles in the promotion and regulation of hepatitis B virus (HBV)-associated liver diseases.MethodsDistribution and expression of IL-17, IFN-γ, IL-4, Foxp3, and other cytokines in liver tissues were detected by immunohistochemistry and real-time quantitative PCR. Patients with hepatitis B were compared with patients with chronic hepatitis C, primary biliary cirrhosis, alcoholic liver cirrhosis, and healthy controls.ResultsThe frequencies of intrahepatic IL-17 and IFN-γ-producing cells in patients with HBV-associated liver dysfunction were much higher than that of IL-4 and Foxp3-positive cells. The level of the IL-17/IFN-γ-positive cell ratio of patients with Child–Pugh class C (1.57 ± 0.09) was much higher than that of patients with Child–Pugh class B (1.00 ± 0.02) or A (0.93 ± 0.05). There are more IL-17-producing cells than IFN-γ-producing cells accumulating in the liver with severe hepatocellular damage. Liver IL-17-producing cell infiltration was positively associated with the grade of liver inflammation in CHB and positively correlated to intrahepatic IL-8 expression (r = 0.801, p < 0.01) or neutrophil infiltration (r = 0.917, p < 0.01).ConclusionsThese results suggest that the balance of effector CD4+ Th responses (Th17 and Th1 responses) and regulatory response is an important element of immune regulation. Inappropriate, excessive, and non-specific Th17 and Th1 effector responses may be involved in the pathogenesis of HBV-associated liver inflammation and hepatocellular damage. Th17 response, especially, may exacerbate the inflammatory processes leading to liver failure. IL-17-mediating liver neutrophil recruitment via induction of IL-8 may be one potential mechanism of liver injury in patients with hepatitis B. An improved understanding of the factors that influence the differentiation and function of these cell types in vivo will be of great importance to the future development of immune therapies in HBV-associated liver disease.

MicroRNA-503 inhibits the G1/S transition by downregulating cyclin D3 and E2F3 in hepatocellular carcinoma

BackgroundIncreasing evidence indicates that deregulation of microRNAs (miRNAs) is involved in tumorigenesis. Downregulation of microRNA-503 has been observed in various types of diseases, including cancer. However, the biological function of miR-503 in hepatocellular carcinoma (HCC) is still largely unknown. In this study we aimed to elucidate the prognostic implications of miR-503 in HCC and its pathophysiologic role.MethodsQuantitative reverse transcriptase polymerase chain reaction was used to evaluate miR-503 expression in HCC tissues and cell lines. Western blotting was performed to evaluate the expression of the miR-503 target genes. In vivo and in vitro assays were performed to evaluate the function of miR-503 in HCC. Luciferase reporter assay was employed to validate the miR-503 target genes.ResultsmiR-503 was frequently downregulated in HCC cell lines and tissues. Low expression levels of miR-503 were associated with enhanced malignant potential such as portal vein tumor thrombi, histologic grade, TNM stage, AFP level and poor prognosis. Multivariate analysis indicated that miR-503 downregulation was significantly associated with worse overall survival of HCC patients. Functional studies showed miR-503 suppressed the proliferation of HCC cells by induction of G1 phase arrest through Rb-E2F signaling pathways, and thus may function as a tumor suppressor. Further investigation characterized two cell cycle-related molecules, cyclin D3 and E2F3, as the direct miR-503 targets.ConclusionOur data highlight an important role for miR-503 in cell cycle regulation and in the molecular etiology of HCC, and implicate the potential application of miR-503 in prognosis prediction and miRNA-based HCC therapy.

Nocardia infection in kidney transplant recipients: case report and analysis of 66 published cases

X. Yu, F. Han, J. Wu, Q. He, W. Peng, Y. Wang, H. Huang, H. Li, R. Wang, J. Chen. Nocardia infection in kidney transplant recipients: case report and analysis of 66 published cases.
Transpl Infect Dis 2011: 13: 385–391. All rights reserved

Association of MDR1 gene SNPs and haplotypes with the tacrolimus dose requirements in Han Chinese liver transplant recipients.

Background This work seeks to evaluate the association between the C/D ratios (plasma concentration of tacrolimus divided by daily dose of tacrolimus per body weight) of tacrolimus and the haplotypes of MDR1 gene combined by C1236T (rs1128503), G2677A/T (rs2032582) and C3435T (rs1045642), and to further determine the functional significance of haplotypes in the clinical pharmacokinetics of oral tacrolimus in Han Chinese liver transplant recipients. Methodology/Principal Findings The tacrolimus blood concentrations were continuously recorded for one month after initial administration, and the peripheral blood DNA from a total of 62 liver transplant recipients was extracted. Genotyping of C1236T, G2677A/T and C3435T was performed, and SNP frequency, Hardy-Weinberg equilibrium, linkage disequilibrium, haplotypes analysis and multiple testing were achieved by software PLINK. C/D ratios of different SNP groups or haplotype groups were compared, with a p value<0.05 considered statistically significant. Linkage studies revealed that C1236T, G2677A/T and C3435T are genetically associated with each other. Patients carrying T-T haplotype combined by C1236T and G2677A/T, and an additional T/T homozygote at either position would require higher dose of tacrolimus. Tacrolimus C/D ratios of liver transplant recipients varied significantly among different haplotype groups of MDR1 gene. Conclusions Our studies suggest that the genetic polymorphism could be used as a valuable molecular marker for the prediction of tacrolimus C/D ratios of liver transplant recipients.

Polymorphism in 3′‐untranslated region of toll‐like receptor 4 gene is associated with protection from hepatitis B virus recurrence after liver transplantation

L. Zhou, B. Wei, C. Xing, H. Xie, X. Yu, L. Wu, S. Zheng. Polymorphism in 3′‐untranslated region of toll‐like receptor 4 gene is associated with protection from hepatitis B virus recurrence after liver transplantation
Transpl Infect Dis 2011: 13: 250–258. All rights reserved

The Efficacy of Surgical Treatment for the Secondary Prevention of Stroke in Symptomatic Moyamoya Disease: A Meta-Analysis.

AbstractThe treatment of moyamoya disease (MMD) is controversial and often depends on the doctors experience. In addition, the choice of surgical procedure to treat MMD can differ in many ways. In this study, we performed a meta-analysis to determine whether surgical treatment of MMD is superior to conservative treatment and to provide evidence for the selection of an appropriate surgical treatment.The human case–control studies regarding the association of MMD treatment were systematically identified through online databases (PubMed, Web of Science, Elsevier Science Direct, and Springer Link). Inclusion and exclusion criteria were defined for the eligible studies. The fixed-effects model was performed when homogeneity was indicated. Alternatively, the random-effects model was utilized.This meta-analysis included 16 studies. Surgical treatment significantly reduced the risk of stroke (odds ratio (OR) of 0.17, 95% confidence interval (CI), 0.12–0.26, P < 0.01). A subgroup analysis showed that surgical treatment was more beneficial to hemorrhagic MMD (OR of 0.23, 95% CI, 0.15–0.38, P < 0.01), but there was no significant difference between surgical treatment and conservative treatment on ischemic MMD treatment (OR of 0.45, 95% CI, 0.15–1.29, P = 0.14). Further analysis indicated that compared to direct bypass surgery, indirect bypass surgery had a lower efficacy on secondary stroke risk reduction (OR of 1.79, 95% CI, 1.14–2.82, P = 0.01), while no significant difference was detected for perioperative complications.Surgery is an effective treatment for symptomatic MMD patients, and direct bypass surgery may bring more benefits for these patients.

Cyclin-dependent kinase inhibitor 3 is overexpressed in hepatocellular carcinoma and promotes tumor cell proliferation

Cyclin-dependent kinase inhibitor 3 (CDKN3) belongs to the protein phosphatases family and has a dual function in cell cycling. The function of this gene has been studied in several kinds of cancers, but its role in human hepatocellular carcinoma (HCC) remains to be elucidated. In this study, we found that CDKN3 was frequently overexpressed in both HCC cell lines and clinical samples, and this overexpression was correlated with poor tumor differentiation and advanced tumor stage. Functional studies showed that overexpression of CDKN3 could promote cell proliferation by stimulating G1-S transition but has no impact on cell apoptosis and invasion. Microarray-based co-expression analysis identified a total of 61 genes co-expressed with CDKN3, with most of them involved in cell proliferation, and BIRC5 was located at the center of CDKN3 co-expression network. These results suggest that CDKN3 acts as an oncogene in human hepatocellular carcinoma and antagonism of CDKN3 may be of interest for the treatment of HCC.

Melatonin-mediated mitophagy protects against early brain injury after subarachnoid hemorrhage through inhibition of NLRP3 inflammasome activation

The NLRP3 inflammasome is activated in the early period following subarachnoid hemorrhage(SAH), resulting in inflammatory responses. Recent studies have shown that activation of NLRP3 inflammasome is suppressed by autophagy, but the potential mechanism is unclear. In this study, we examined whether mitophagy was involved in the beneficial effect of melatonin and its relationship with NLRP3 inflammasome activation after SAH. In total, 130 adult-male SD rats were randomly divided into four groups: sham group, SAH + vehicle group, SAH + melatonin group, and SAH + 3-methyladenine (3-MA) + melatonin group. Brain samples were used for brain water content analysis, ROS assay, Western blot, immunohistochemistry and transmission electron microscopy. The results showed that melatonin treatment markedly increased the expression of both autophagy markers(LC3-II/LC3-I and Atg 5), and mitophagy markers(Parkin and PINK-1) following SAH induction. Additionally, melatonin treatment attenuated pathological changes in mitochondria and reduced ROS generation, which are closely related to NLRP3 inflammasome activation. Consequently, melatonin-mediated upregulation of proteins associated with mitophagy inhibited NLRP3 inflammasome activation and significantly reduced pro-inflammatory cytokine levels after SAH. Conversely, 3-MA, an autophagy inhibitor, reversed these beneficial effects of melatonin on mitophagy and the NLRP3 inflammasome. These results suggest that mitophagy-associated NLRP3 inflammasome inhibition by melatonin is neuroprotective against early brain injury post-SAH in rats.

Short-term effects of particulate matter on stroke attack: meta-regression and meta-analyses.

Background and Purpose Currently there are more and more studies on the association between short-term effects of exposure to particulate matter (PM) and the morbidity of stroke attack, but few have focused on stroke subtypes. The objective of this study is to assess the relationship between PM and stroke subtypes attack, which is uncertain now. Methods Meta-analyses, meta-regression and subgroup analyses were conducted to investigate the association between short-term effects of exposure to PM and the morbidity of different stroke subtypes from a number of epidemiologic studies (from 1997 to 2012). Results Nineteen articles were identified. Odds ratio (OR) of stroke attack associated with particular matter (“thoracic particles” [PM10]<10 µm in aerodynamic diameter, “fine particles” [PM2.5]<2.5 µm in aerodynamic diameter) increment of 10 µg/m3 was as effect size. PM10 exposure was related to an increase in risk of stroke attack (OR per 10 µg/m3 = 1.004, 95%CI: 1.001∼1.008) and PM2.5 exposure was not significantly associated with stroke attack (OR per 10 µg/m3 = 0.999, 95%CI: 0.994∼1.003). But when focused on stroke subtypes, PM2.5 (OR per 10 µg/m3 = 1.025; 95%CI, 1.001∼1.049) and PM10 (OR per 10 µg/m3 = 1.013; 95%CI, 1.001∼1.025) exposure were statistically significantly associated with an increased risk of ischemic stroke attack, while PM2.5 (all the studies showed no significant association) and PM10 (OR per 10 µg/m3 = 1.007; 95%CI, 0.992∼1.022) exposure were not associated with an increased risk of hemorrhagic stroke attack. Meta-regression found study design and area were two effective covariates. Conclusion PM2.5 and PM10 had different effects on different stroke subtypes. In the future, its worthwhile to study the effects of PM to ischemic stroke and hemorrhagic stroke, respectively.

Assessment of biological characteristics of mesenchymal stem cells labeled with superparamagnetic iron oxide particles in vitro

Mesenchymal stem cell (MSC) transplantation provides a novel strategy for the treatment of human disease. MR imaging (MRI) is able to track transplanted stem cells labeled with superparamagnetic iron oxide (SPIO) in vivo. However, the effect of SPIO upon labeled MSCs remains unclear on a cellular level. In this study, the biological characteristics of rat MSCs labeled with home-synthesized SPIO particles were evaluated. The MSCs were isolated from the bone marrow of 5 adult Sprague-Dawley rats and labeled with home-synthesized SPIO particles at a final iron concentration of 20 µg/ml. Labeled MSCs were confirmed with Prussian blue staining and transmission electron microscopy. The quantity of iron per cell was determined by atomic absorption spectrometry. Cell viability, proliferation, membranous antigen and multiple differentiation ability were compared between labeled and unlabeled MSCs. The rat MSCs were effectively labeled and the labeling efficiency was approximately 100%, as revealed by Prussian blue staining. The SPIO particles located in the endosomal vesicles of the MSCs were confirmed by transmission electron microscopy. No significant differences were observed in cell viability, proliferation, membranous antigen and multiple differentiation ability between the labeled and unlabeled MSCs (P>0.05). In conclusion, MSCs are able to be effectively labeled by home-synthesized SPIO particles without influencing their main biological characteristics.