Chung-Yi Hu

Hepatitis C Virus Core Protein Modulates TRAIL-Mediated Apoptosis by Enhancing Bid Cleavage and Activation of Mitochondria Apoptosis Signaling Pathway

Hepatitis C virus (HCV) is a major human pathogen causing chronic liver disease, which leads to cirrhosis of liver and hepatocellular carcinoma. The HCV core protein, a viral nucleocapsid, has been shown to affect various intracellular events, including cell proliferation and apoptosis. However, the precise mechanisms of the effects are not fully understood. In this study, we show that HCV core protein sensitizes human hepatocellular carcinoma cell line, Huh7, conferred sensitivity to TRAIL-, but not Fas ligand-mediated apoptosis. Huh7 cells are resistant to TRAIL, despite the induction of caspase-8 after TRAIL engagement. However, HCV core protein induces TRAIL apoptosis signaling via sequential induction of caspase-8, Bid cleavage, activation of mitochondrial pathway, and effector caspase-3. HCV core protein also induces activation of caspase-9 after TRAIL engagement, and the induction of TRAIL sensitivity by HCV core protein could be reversed by caspase-9 inhibitor. Therefore, the HCV core protein-induced TRAIL-mediated apoptosis is dependent upon activation of caspase-8 downstream pathway to convey the death signal to mitochondria, leading to activation of mitochondrial signaling pathway and breaking the apoptosis resistance. These results combined indicate that the HCV core protein enhances TRAIL-, but not Fas ligand-mediated apoptotic cell death in Huh7 cells via a mechanism dependent on the activation of mitochondria apoptosis signaling pathway. These results suggest that HCV core protein may have a role in immune-mediated liver cell injury by modulation of TRAIL-induced apoptosis.

Characterization of the spectrum of postthymic T-cell malignancies in Taiwan. A clinicopathologic study of HTLV-1-positive and HTLV-1-negative cases.

Postthymic T‐cell malignancy shows marked geographic, clinicopathologic, and prognostic diversity. The frequency and spectrum of T‐cell malignancies in Taiwan were investigated. Fifty‐two patients (35 male and 17 female) with a median age of 49 years, were consecutively encountered between October 1983 and April 1987; these accounted for 39% of non‐Hodgkins lymphoma cases seen in our institutions. Ten patients (19.3%) had adult T‐cell leukemia/lymphoma (ATL) associated with human T‐cell leukemia virus (HTLV‐1). Patients with ATL had disease similar to that reported from southwestern Japan and the Caribbean. They had frequent skin lesions (60%), hypercalcemia (40%), and a rapid clinical course with a median survival of 1.3 years. The 35 HTLV‐1‐negative peripheral T‐cell lymphomas (PTL) were similar to PTL in western countries, manifesting frequent visceral, cutaneous, and vascular tropisms. Marrow involvement was documented at presentation in 39% and Stage III/IV disease in 80% of the PTL patients. The histology of PTL usually expressed prominent reactive features which is distinct from that in ATL. Several subcategories could be defined: Hodgkins‐like PTL in nine patients, T‐zone lymphoma in three, angioimmunoblastic lymphadenopathy‐like lymphoma in one, Lennerts lymphoma in three, and angioinvasive lymphoma in four. Two HTLV‐1‐negative PTL had neoplasiic cells with clover‐shaped nuclei and were designated as ATL‐like. Morphologic classification based on the modified Working Formulation showed prognostic correlation, with median survival of less than 6 months for large cell/immunoblastic PTL, compared with 5 years for patients with small/medium cell PTL. Both low‐ and high‐grade PTL seem to represent an incurable disease. Classical cutaneous T‐cell lymphoma (seven cases) is relatively unusual in Taiwan, compared with the frequency of PTL. Post‐thymic T‐cell malignancies in Taiwan include HTLV‐1‐positive and HTLV‐1‐negative diseases, both of which have a poor prognosis and resemble similar T‐cell malignancies in the East and West.

Association of insulin-dependent diabetes mellitus in Taiwan with HLA class II DQB1 and DRB1 alleles

The allelic constitution at HLA class II DRB1, DQB1, DQA1, and DPB1 loci of IDDM patients from Taiwan was compared with that of ethnically matched nondiabetic individuals by PCR-based DNA typing. Of the three haplotypes found to be positively associated with IDDM in Taiwan, two (DRB1*0301-DQA1*0501-DQB1*0201 and DR4-DQA1*0301-DQB1*0302) appear to be identical to the susceptible haplotypes in Caucasian and black populations, whereas the third haplotype (DR4-DQA1*0301-DQB1*04) has been reported to be positively associated with IDDM only in the Japanese population. The three haplotypes, DRB1*1502-DQA1*0102-DQB1*0601 and DRB1*1201 (or 1202)-DQA1*0501-DQB1*0301 and DRB1*0803-DQA1*0103-DQB1*0601, were negatively associated with IDDM in Taiwan; a protective effect of the last haplotype has not been reported previously. Neither DQ beta non-Asp-57 nor DQA1*0301 alone appears sufficient to account for the HLA-associated susceptibility to IDDM in Taiwan. Also, the DQ alpha beta heterodimer encoded by the alleles DQA1*0301/DQB1*0201, DQA1*0301/DQB1*0302, or DQA1*0501/DQB1*0201 does not explain the susceptibility of a larger fraction of the IDDM patients than the residue at position 57 of the DQ beta chain or DQA1*0301. Finally, the DRB1 alleles appear to affect IDDM susceptibility, although for most haplotypes the effect of individual loci cannot be assessed due to the linkage disequilibrium between the DQ and the DR region.

Genetic polymorphism in milk fat globule-EGF factor 8 (MFG-E8) is associated with systemic lupus erythematosus in human

Milk fat globule-EGF factor 8 (MFG-E8) is a molecule implicated in phagocytic clearance of apoptotic cells by bridging between macrophages and apoptotic cells. Defects in MFG-E8 cause lupus-like disease in murine models. The aim of our study is to determine whether genetic variation in MFG-E8 predisposes human to systemic lupus erythematosus (SLE). A case-control study of MFG-E8 genetic polymorphism was performed on 147 SLE patients and 146 non-lupus control subjects. Single nucleotide polymorphisms (SNPs) in the coding sequence of human MFG-E8 gene were investigated. SNPs on MFG-E8 residues 3 (3Arg or Ser) and 76 (76Leu or Met) did not show genetic linkage. Genetic polymorphism on MFG-E8 residue 76 correlated significantly to SLE. The MFG-E8-76Met allele predisposed subjects to SLE in a recessive mode (odds ratio: 2.1, P = 0.020), while carriage of MFG-E8-76Leu were negatively associated with SLE. The MFG-E8 genotypic combinations with 3Ser and 76Leu showed the most pronounced protective effect on SLE when compared to the most predisposing genotype 3Arg/Arg-76Met/Met (OR: 0.29, P = 0.007). According to our result, MFG-E8 is associated with SLE predisposition in Taiwanese. Our study implicates that the impairment of phagocytic clearance of apoptotic cells through phosphotidylserine-dependent MFG-E8 system may lead to the development of human SLE.

Marrow angiogenesis-associated factors as prognostic biomarkers in patients with acute myelogenous leukaemia.

Bone marrow (BM) neoangiogenesis plays an important role in acute myelogenous leukaemia (AML), and depends on the interplay of members of the vascular endothelial growth factor (VEGF) and angiopoietin (Ang) families. We determined the marrow levels of seven molecules associated with angiogenesis in 52 AML patients before chemotherapy and 20 healthy controls: VEGF-A, VEGF/PlGF, VEGF-C, VEGF-D, Ang-1, Ang-2, and Tie-2. All the molecules were quantified using enzyme-linked immunosorbent assay (ELISA). Comparing to normal controls, the marrow levels of VEGF/PlGF, Ang-2, and Tie-2 were significantly higher, and those of VEGF-C and Ang-1 were significantly lower in the AML patients (P<0.001). A total of 31 patients were further subjected to survival analysis. Patients with lower Tie-2 (<26 ng ml−1) and Ang-2 levels (<4500 pg ml−1) displayed a survival advantage (P=0.037 and 0.042, respectively), same as patients with higher VEGF/PlGF (⩾1 pg ml−1) and VEGF-D levels (⩾350 pg ml−1) (P=0.020 and 0.016, respectively). An angio-index ((Ang-2 × Tie-2)/(VEGF/PlGF × VEGF-D)) was established and multivariate Cox regression analysis revealed that patients with higher angio-index values (⩾50) displayed poor prognosis (hazard ratio 5.91, 95% confidence interval 1.99–17.56; P=0.001). The angio-index is closely associated with the clinical outcome of AML patients and may be valuable in disease prognosis.

Elevated serum decoy receptor 3 with enhanced T cell activation in systemic lupus erythematosus

Decoy receptor 3 (DcR3/TR6) is a decoy receptor for the Fas ligand (FasL) and can inhibit FasL‐induced apoptosis. It has been reported recently that DcR3 can induce T cell activation via co‐stimulation of T cells, suggesting that DcR3 may be involved in the pathophysiology of autoimmune diseases. This study aims to analyse the serum DcR3 in patients with systemic lupus erythematosus (SLE) and to investigate the role of DcR3 in the pathogenesis of SLE. Significantly elevated serum DcR3 was observed in SLE patients, and the mean serum DcR3 level was significantly higher for those with active disease [SLE disease activity index (SLEDAI) ≥ 10] compared with that in patients with inactive disease (SLEDAI < 10). In addition to reducing activation‐induced cell death in activated T cells via neutralization of the FasL, soluble DcR3–Fc enhanced T cell proliferation and increased interleukin‐2 and interferon‐γ production via co‐stimulation of T cells. Moreover, enhanced T cell reactivity to DcR3‐induced co‐stimulation was demonstrated in lymphocytes from patients with SLE, suggesting the elevated serum DcR3 may associate with enhanced T cell activation in vivo. These findings are the first to demonstrate that serum DcR3 concentrations are increased in SLE patients, and this may imply a possible role of DcR3 in the pathogenesis of SLE via enhanced T cell hyperreactivity and reduced apoptosis in activated T cells.

Association of catechol-O-methyltransferase (COMT) polymorphism and academic achievement in a Chinese cohort

Catechol-O-methyltransferase (COMT) is a methylation enzyme that catalyzes the degradation pathway and inactivation of dopamine. It is accepted widely as being involved in the modulation of dopaminergic physiology and prefrontal cortex (PFC) function. The COMT Val158Met polymorphism is associated with variation in COMT activity. COMT 158Met allele may be advantageous for PFC-related cognitive abilities; however, it is also associated with increased anxiety, depression, and emotional vulnerability in response to stress or educational adversity. We hypothesized that the COMT polymorphism might be associated with academic performance. In this study, 779 Taiwanese tenth-grade volunteers were recruited. Scores from the Basic Competency Test (BCT), an annual national competitive entrance examination, were used to evaluate academic performance. The results indicated that students bearing homozygous for the Met allele tended to perform more poorly in all BCT subtests as compared to the other groups. In particular, the former performed significantly more poorly in the science and social science subtests. These findings provide evidence that affective factors might overwhelm cognitive abilities in high-stake tests like the BCT.

Galectin-3 gene (LGALS3) +292C allele is a genetic predisposition factor for rheumatoid arthritis in Taiwan.

Galectin-3 is a beta-galactoside-binding lectin which is involved in modulating inflammation and apoptosis. Elevated expression of galectin-3 has been demonstrated in synovium of rheumatoid arthritis (RA). The aim of our study is to investigate the genetic polymorphisms of galectin-3 in association with RA. Polymorphisms of galectin-3 gene (LGALS3) were compared between 151 RA patients and 182 healthy subjects in Taiwan. Variants at two LGALS3 single nucleotide polymorphism (SNP) sites (rs4644 and rs4652, corresponding to LAGLS3 +191 and +292) were genotyped by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) and sequence-specific oligonucleotide probe hybridization, respectively. The allelic carriage of LGALS3 +292C was increased in patients with RA (66.9% in RA vs. 52.7% in controls, odds ratio = 1.8, 95% confidence interval = 1.2–2.8, p = 0.009). These results implicate that the genetic polymorphisms in galectin-3 gene may contribute to development of RA.

HLA polymorphism among Chinese patients with chronic plaque psoriasis: subgroup analysis.

Background  HLA‐Cw*06 has a strong influence on the clinical features and the susceptibility to psoriasis in different ethnicities. It is also used as a biomarker to predict the therapeutic efficacy of biologics, with inconsistent results. Additionally, most Asian patients with psoriasis do not carry HLA‐Cw*06.

HLA DPB1*0201 allele is negatively associated with immunoglobulin E responsiveness specific for house dust mite allergens in Taiwan.

House dust mite (HDM) Dermatophagoides pteronyssinus is the most important source of indoor allergens that cause allergic diseases in Taiwan. We prepared purified HDM allergens (Der p 1, Der p 2 and Der p 5) to detect allergen‐specific immunoglobulin (Ig) E responsiveness among a large number of test subjects. The robust genetic typing system for HLA class II genes also facilitated the study on association of HLA and allergic response toward HDM.