Yuxian Huang

CYLD negatively regulates transforming growth factor-β-signalling via deubiquitinating Akt.

Lung injury, whether induced by infection or caustic chemicals, initiates a series of complex wound-healing responses. If uncontrolled, these responses may lead to fibrotic lung diseases and loss of function. Thus, resolution of lung injury must be tightly regulated. The key regulatory proteins required for tightly controlling the resolution of lung injury have yet to be identified. Here we show that loss of deubiquitinase CYLD led to the development of lung fibrosis in mice after infection with Streptococcus pneumoniae. CYLD inhibited transforming growth factor-β-signalling and prevented lung fibrosis by decreasing the stability of Smad3 in an E3 ligase carboxy terminus of Hsc70-interacting protein-dependent manner. Moreover, CYLD decreases Smad3 stability by deubiquitinating K63-polyubiquitinated Akt. Together, our results unveil a role for CYLD in tightly regulating the resolution of lung injury and preventing fibrosis by deubiquitinating Akt. These studies may help develop new therapeutic strategies for preventing lung fibrosis.

Analysis of microRNA expression profiling identifies miR-155 and miR-155* as potential diagnostic markers for active tuberculosis: a preliminary study

To explore biologic behaviors and disease relevance of microRNAs (miRNAs) in the development of active tuberculosis (ATB), we investigated the expression profile of Mycobacterium tuberculosis (MTB) purified protein derivative (PPD)-induced miRNAs to determine the specific miRNAs involved in the pathogenesis of ATB. The expression profile of miRNA under PPD challenge was first measured using microarray analysis in peripheral blood mononuclear cells isolated from ATB patients and healthy controls (HC). The remarkably reactive miRNAs were then validated in a larger cohort by quantitative real-time polymerase chain reaction (qRT-PCR). The receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic value of the determined PPD-responsive miRNAs. The potential targets for those miRNAs were also predicted by computational programs. Fourteen of 866 human miRNAs exhibited at least 1.8-fold difference in the ratio of expression level before and after stimulation with PPD between the ATB and HC groups. The qRT-PCR study validated the findings from microarray-based screening, in which miR-155 exhibited a fold change of 1.4 in the HC group and 3.7 in the ATB group upon PPD stimulation (p < 0.0001); miR-155* exhibited a fold change of 1.9 in the HC and 4.6 in the ATB group (p < 0.005). In ROC plots, the area under the curve was 0.8972 for miR-155 and 0.7945 for miR-155*. The background expression of these 2 microRNAs exhibited no differences between the ATB and HC groups. miR-155 and miR-155* exhibited characteristic expression by TB-specific antigen, suggesting that they can be potential diagnostic markers under the challenge of specific MTB antigens.

A case study of the highly time-resolved evolution of aerosol chemical and optical properties in urban Shanghai, China

Characteristics of the chemical and optical properties of aerosols in urban Shanghai and their relationship were studied over a three-day period in October 2011. A suite of real-time instruments, including an Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS), a Monitor for AeRosols and GAses (MARGA), a Cavity Ring Down Spectrometer (CRDS), a nephelometer and a Scanning Mobility Particle Sizer (SMPS), was employed to follow the quick changes of the aerosol properties within the 72 h sampling period. The origin of the air mass arriving in Shanghai during this period shifted from the East China Sea to the northwest area of China, offering a unique opportunity to observe the evolution of aerosols influenced by regional transport from the most polluted areas in China. According to the meteorological conditions and temporal characterizations of the chemical and optical properties, the sampling period was divided into three periods. During Period 1 (00:00–23:00 LT, 13 October), the aerosols in urban Shanghai were mainly fresh and the single scattering albedo varied negatively with the emission of elemental carbon, indicating that local sources dominated. Period 2 (23:00 LT on 13 October to 10:00 LT on 15 October) was impacted by regionally transported pollutants and had the highest particulate matter (PM) mass loading and the lowest particle acidity, characterized by large fractions of aged particles and high secondary ion (nitrate, sulfate and ammonium) mass concentrations. Comparison between ATOFMS particle acidity and quantitative particle acidity by MARGA indicated the significance of semi-quantitative calculation in ATOFMS. Two sub-periods were identified in Period 2 based on the scattering efficiency of PM 1 mass. Period 3 (from 10:00 LT on 15 October to 00:00 LT on 16 October) had a low PM1/PM10 ratio and a new particle formation event. The comparison of these sub-periods highlights the influence of particle mixing state on aerosol optical properties. We directly observed the influence of regionally transported pollutants on local aerosol properties and demonstrate that the PM mass extinction efficiency is largely determined by the mixing states of the aerosol.

Transcription of Hepatitis B Virus Covalently Closed Circular DNA Is Regulated by CpG Methylation during Chronic Infection

The persistence of hepatitis B virus (HBV) infection is maintained by the nuclear viral covalently closed circular DNA (cccDNA), which serves as transcription template for viral mRNAs. Previous studies suggested that cccDNA contains methylation-prone CpG islands, and that the minichromosome structure of cccDNA is epigenetically regulated by DNA methylation. However, the regulatory effect of each CpG island methylation on cccDNA activity remains elusive. In the present study, we analyzed the distribution of CpG methylation within cccDNA in patient samples and investigated the impact of CpG island methylation on cccDNA-driven virus replication. Our study revealed the following observations: 1) Bisulfite sequencing of cccDNA from chronic hepatitis B patients indicated that CpG island I was seldom methylated, 2) CpG island II methylation was correlated to the low level of serum HBV DNA in patients, and in vitro methylation studies confirmed that CpG island II methylation markedly reduced cccDNA transcription and subsequent viral core DNA replication, 3) CpG island III methylation was associated with low serum HBsAg titers, and 4) Furthermore, we found that HBV genotype, HBeAg positivity, and patient age and liver fibrosis stage were also relevant to cccDNA CpG methylation status. Therefore, we clearly demonstrated that the status of cccDNA methylation is connected to the biological behavior of HBV. Taken together, our study provides a complete profile of CpG island methylation within HBV cccDNA and new insights for the function of CpG methylation in regulating HBV cccDNA transcription.

HBx elevates oncoprotein AEG-1 expression to promote cell migration by downregulating miR-375 and miR-136 in malignant hepatocytes.

The hepatitis B viral X protein (HBx) has been established to implicate in the development of HBV-related hepatocellular carcinoma (HCC) via multiple pathways. The oncoprotein astrocyte elevated gene-1 (AEG-1) is overexpressed in various tumors, including HCC, and plays critical roles in promoting cell migration and invasion. However, the mechanisms for AEG-1 upregulation in tumors are largely unknown. In this study, we found that HBx could elevate AEG-1 protein level without altering its mRNA level. When blocking AEG-1 expression with siRNA in HBx-transfected cells, the HBx-induced cell migration was significantly suppressed. Further study indicated that miR-375 and miR-136 that targeted AEG-1 were downregulated with HBx expression. Overexpressing miR-375 and miR-136 could effectively attenuate HBx-mediated AEG-1 elevation and cell migration. These results demonstrated that HBx enabled to increase oncoprotein AEG-1 expression to promote cell migration via downregulating miR-375 and miR-136. Our findings provide a novel insight into AEG-1 upregulation in HCC and shed new light on HBx promoting HCC progression. Meanwhile, our results also suggest that miR-375 and miR-136 may have the miRNA-based therapeutic potential in HBV-associated HCC.

EVI1 Acts as an Inducible Negative-Feedback Regulator of NF-κB by Inhibiting p65 Acetylation

Inflammation is a hallmark of many important human diseases. Appropriate inflammation is critical for host defense; however, an overactive response is detrimental to the host. Thus, inflammation must be tightly regulated. The molecular mechanisms underlying the tight regulation of inflammation remain largely unknown. Ecotropic viral integration site 1 (EVI1), a proto-oncogene and zinc finger transcription factor, plays important roles in normal development and leukemogenesis. However, its role in regulating NF-κB–dependent inflammation remains unknown. In this article, we show that EVI1 negatively regulates nontypeable Haemophilus influenzae- and TNF-α–induced NF-κB–dependent inflammation in vitro and in vivo. EVI1 directly binds to the NF-κB p65 subunit and inhibits its acetylation at lysine 310, thereby inhibiting its DNA-binding activity. Moreover, expression of EVI1 itself is induced by nontypeable Haemophilus influenzae and TNF-α in an NF-κB–dependent manner, thereby unveiling a novel inducible negative feedback loop to tightly control NF-κB–dependent inflammation. Thus, our study provides important insights into the novel role for EVI1 in negatively regulating NF-κB–dependent inflammation, and it may also shed light on the future development of novel anti-inflammatory strategies.

The Gamma-Glutamyl-Transpeptidase to Platelet Ratio Does not Show Advantages than APRI and Fib-4 in Diagnosing Significant Fibrosis and Cirrhosis in Patients With Chronic Hepatitis B: A Retrospective Cohort Study in China

AbstractThe gamma-glutamyl-transpeptidase to platelet ratio (GPR) is a new liver fibrosis model, which is reported to be more accurate than aspartate transaminase (AST) to platelet ratio index (APRI) and fibrosis index based on the four factors (Fib-4) for diagnosing significant fibrosis and cirrhosis in patients with chronic hepatitis B (CHB) in West Africa.The aim of this study is to assess the diagnostic accuracy of GPR for significant fibrosis and cirrhosis in Chinese CHB patients, and explore whether GPR deserves to be popularized in China.A total of 372 CHB patients who underwent liver biopsies and routine laboratory tests were retrospectively studied. The Scheuer scoring system was adopted as the pathological standard of liver fibrosis. Using liver histology as a gold standard, the diagnostic accuracies of GPR, APRI, and Fib-4 for significant fibrosis and cirrhosis are evaluated and compared by the receiver operating characteristic (ROC) curves and the area under the ROC curves (AUROCs).Of these 372 patients, 176 (47.3%), 129 (34.7%), and 72 (19.4%) were classified as having significant fibrosis (≥ S2), severe fibrosis (≥ S3), and cirrhosis (S4), respectively. The AUROCs of GPR for significant fibrosis (0.72 vs. 0.78; P = 0.01), severe fibrosis (0.75 vs. 0.80; P = 0.04), and cirrhosis (0.78 vs. 0.83; P = 0.02) were lower than those of APRI. The AUROCs of GPR and Fib-4 for diagnosing significant fibrosis (0.72 vs. 0.70; P = 0.29), severe fibrosis (0.75 vs. 0.73; P = 0.33), and cirrhosis (0.78 vs. 0.75; P = 0.38) were comparable.GPR is a new serum diagnostic model for liver fibrosis and cirrhosis, but does not show advantages than APRI and Fib-4 in identifying significant fibrosis, severe fibrosis, and cirrhosis in CHB patients in China.

Impact of Nucleos(t)ide Analogue Combination Therapy on the Estimated Glomerular Filtration Rate in Patients With Chronic Hepatitis B

AbstractMonotherapy with telbivudine or adefovir can affect estimated the glomerular filtration rate (eGFR). However, only a few studies have assessed changes in eGFR in patients who have chronic hepatitis B (CHB) and are receiving nucleos(t)ide analogue (NA) combination therapy. In our study, we aimed to evaluate the effects of long-term NA combination therapy on eGFR in Chinese CHB patients.This retrospective study included 195 CHB patients. Patient subgroups included those treated with lamivudine plus adefovir (n = 73), telbivudine plus adefovir (n = 51), and entecavir plus adefovir (n = 35); untreated patients (n = 36) served as a control group.After an average follow-up duration of 24 months with combination therapy, analysis of changes in eGFR from baseline values, calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) formulas, showed decrease by11.08 and 18.34 mL/min (P < .001), respectively, in the lamivudine plus adefovir group; decrease by 3.73 and 10.04 mL/min (P = .012), respectively, in the entecavir plus adefovir group; and increase by 0.91 and 2.12 mL/min (P = .46), respectively, in the telbivudine plus adefovir group. The eGFR in the telbivudine plus adefovir group was similar to that for the untreated group. The eGFR decreases due to adefovir therapy could be rescued by adding telbivudine, and the eGFR increase due to telbivudine could be compromised by adding adefovir.Adefovir in combination with lamivudine or entecavir therapy was significantly associated with decreased eGFR, but telbivudine could rescue the eGFR decrease that results from adefovir treatment.

CYLD Negatively Regulates Nontypeable Haemophilus influenzae-Induced IL-8 Expression via Phosphatase MKP-1-Dependent Inhibition of ERK

Nontypeable Haemophilus influenzae (NTHi), a Gram-negative bacterium, is the primary cause of otitis media in children and the exacerbation of chronic obstructive pulmonary disease in adults. A hallmark of both diseases is an overactive inflammatory response, including the upregulation of chemokines, such as interleukin-8 (IL-8). An appropriate inflammatory response is essential for eradicating pathogens. However, excessive inflammation can cause host tissue damage. Therefore, expression of IL-8 must be tightly regulated. We previously reported that NTHi induces IL-8 expression in an ERK-dependent manner. We also have shown that the deubiquitinase cylindromatosis (CYLD) suppresses NTHi-induced inflammation. However, the underlying molecular mechanism of how CYLD negatively regulates ERK-mediated IL-8 production is largely unknown. Here, we examine both human lung epithelial A549 cells and lung of Cyld −/− mice to show that CYLD specifically targets the activation of ERK. Interestingly, CYLD enhances NTHi-induced upregulation of another negative regulator, MAP Kinase Phosphatase-1 (MKP-1), which, in turn, leads to reduced ERK activation and subsequent suppression of IL-8. Taken together, the CYLD suppression of ERK-dependent IL-8 via MKP-1 may bring novel insights into the tight regulation of inflammatory responses and also lead to innovative therapeutic strategies for controlling these responses by targeting key negative regulators of inflammation.

Evaluation of APRI and FIB-4 for noninvasive assessment of significant fibrosis and cirrhosis in HBeAg-negative CHB patients with ALT ≤ 2 ULN: A retrospective cohort study

Abstract To evaluate the performance of aspartate transaminase-to-platelet ratio index (APRI) and fibrosis index based on four factors (FIB-4) to predict significant fibrosis and cirrhosis in hepatitis B virus e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients with alanine transaminase (ALT) ⩽ twice the upper limit of normal (2 ULN). Histologic and laboratory data of 236 HBeAg-negative CHB patients with ALT ⩽ 2 ULN were analyzed. Predicted fibrosis stage, based on established scales and cut-offs for APRI and FIB-4, was compared with METAVIR scores obtained from liver biopsy. In this study, the areas under the receiver operating characteristic curves (AUROCs) of APRI were lower than that of FIB-4 (0.62 vs 0.69; P = 0.019) for diagnosing significant fibrosis; however APRI and FIB-4 were comparable for diagnosing cirrhosis (0.77 vs 0.81; P = 0.374). When the cut-off proposed by WHO HBV guideline for APRI (>2.0) was used, no cirrhotic patients were correctly predicted. For FIB-4, the WHO proposed cut-off of 3.25 correctly identified significant fibrosis 83% of the time; but for APRI, the WHO proposed cut-off of 1.5 identified significant fibrosis 56%. In ruling out significant fibrosis, the WHO proposed APRI cut-off of 0.5 had a predictive value of 39%, and the FIB-4 cut-off of 1.45 correctly identified lack of significant fibrosis in 47% of the patients. In this study, based on ROC analysis, the optimal cut-offs were 0.46 and 0.65 for APRI, and 1.05 and 1.29 for FIB-4, for diagnosing significant fibrosis and cirrhosis, respectively. When the new cut-off of APRI (>0.65) was used, 82% of the cirrhotic patients were correctly predicted. In ruling out significant fibrosis, the new APRI cut-off (<0.46) had a predictive value of 80%, and new FIB-4 cut-off (<1.05) correctly identified lack of significant fibrosis in 84% of the patients. The WHO guidelines proposed cut-offs might be higher for HBeAg-negative CHB patients with ALT ⩽2 ULN, and might underestimate the proportion of significant fibrosis and cirrhosis. A new set of cut-offs should be used to predict significant fibrosis and cirrhosis in this specific population.