Association between C1431T polymorphism in peroxisome proliferator-activated receptor-γ gene and coronary artery disease in Chinese Han population

The C1431T polymorphism in peroxisome proliferator-activated receptor-γ (PPARγ) has been shown to be associated with diabetes, obesity, and metabolic syndrome. However, it is unclear whether this polymorphism is associated with coronary artery disease (CAD). Therefore, we conducted a hospital-based case–control study with 864 CAD patients and 1008 controls to explore the association between the PPARγ C1431T polymorphism and risk of CAD in Chinese Han population. Subjects with the variant genotypes (CT + TT) had a 39% decreased risk of CAD relative to CC carriers (adjusted odds ratio, 0.61; 95% confidence interval, 0.49–0.76). Our results suggested that the C1431T polymorphism was associated with a higher body mass index in both CAD patients and controls. Moreover, this polymorphism was also found to be associated with a higher HDL cholesterol level and a lower blood glucose level in CAD patients. In stratified analyses, the T allele was significantly associated with reduced risk of CAD in males, subjects with age <62 years, and non-smokers. In conclusion, the PPARγ C1431T polymorphism is associated with decreased risk of CAD in Chinese Han population.     

Association between clinical expression and molecular heterogeneity in β-thalassemia Tunisian patients

Beta-thalassemia is the most frequent hereditary blood disorder in Tunisia because of its geographic localization and history. This pathology is characterized by a complex multisystem process with genetic and biochemical interactions. The aim of this work was to establish phenotype/genotype association through studying the distribution and the relationship between β-thalassemia and α-thalassemia mutations and three polymorphic markers: the C → T polymorphism at ?158 of the Gγ gene, the RFLP haplotype and the repeated sequence (AT)_xT_y in the β globin silencer, in two groups of β-thalassemia major and β-thalassemia intermedia (TI) patients. Statistical analysis has shown that moderate expression seen in TI patients was significantly associated to β⁺ ?87 (C → G), ?30 (T → A) and IVSI-6 (T → C) mutations, haplotypes VIII, IX and Nb and to XmnI polymorphism. The regression analysis of combined genotypes (mutation/XmnI/RFLP haplotype) revealed that they contribute to justify 17.1 % of clinical expression diversity (p < 0.05). Among the studied genotypes the XmnI polymorphism seems to be the most determinant modulating factor, followed by the β-thalassemia mutation and RFLP haplotype. Our findings highlight the heterogeneity of molecular background of β-thalassemia that would be responsible of clinical variability.     

The association between endothelial lipase ?384A/C gene polymorphism and acute coronary syndrome in a Chinese population

Endothelial lipase (EL) is a novel member of the triglyceride (TG) lipase family. A growing body of evidence has indicated that EL gene polymorphism might contribute to the process of cardiovascular diseases. This study was aimed to reveal the potential relationship between EL -384A/C gene polymorphism and acute coronary syndrome (ACS) in a Chinese Han population. The subjects were composed of 320 ACS patients and 315 age- and gender- matched controls. We detected the EL -384A/C genotypes and allele frequencies by using polymerase chain reaction-restriction fragment length polymorphism analysis. There was significant difference in AA genotype and AC+CC genotype between ACS and control groups (P?=?0.014). The A allele frequency was significantly higher in ACS group than in control group (87.8 vs 83.8?%, P?=?0.041). The relationship between the variant and ACS remained significant after adjusting for current smoker, hypertension, diabetes mellitus, total cholesterol and TG (OR?=?0.682, 95?% CI?=?0.472-0.986). The levels of HDL and ApoA-I were significantly higher in AC+CC genotype than in AA genotype (HDL: 1.20?±?0.35 vs 1.11?±?0.29?mmol/L, P?=?0.001; ApoA-I: 1.14?±?0.25 vs 1.08?±?0.21?g/L, P?=?0.009). We found that the EL -384A/C gene polymorphism might be associated with ACS in Chinese Han population, suggesting that the variant might be involved in the pathogenesis of ACS.     

Monocyte-produced prostaglandin induces Fcγ receptor expression on human T cells

Incubation of human T cells for 18 hr with prostaglandin E₂ (PGE₂ 3 × 10^?6M) causes a slight but significant increase in the percentage of Tγ cells and a reduction in Tμ cells. When PGE was added to “non-Tγ” cells, the increase in the percentage of Tγ cells was more marked (from 1.5% Tγ without PGE to 11% Tγ with PGE₂, P < 0.001). Supernates from cultures of human monocytes also caused an increase in Tγ cells (10% Tγ without supernate to 18% with supernate, P < 0.01), and this increase was blocked if the monocytes were cultured with indomethacin, a prostaglandin synthetase inhibitor (9% Tγ cells). Thus, monocytes may regulate Fcγ receptors on T cells via PGE₂ production.     

Human Cytomegalovirus Fcγ Binding Proteins gp34 and gp68 Antagonize Fcγ Receptors I,II and III

Human cytomegalovirus (HCMV) establishes lifelong infection with recurrent episodes of virus production and shedding despite the presence of adaptive immunological memory responses including HCMV immune immunoglobulin G (IgG). Very little is known how HCMV evades from humoral and cellular IgG-dependent immune responses, the latter being executed by cells expressing surface receptors for the Fc domain of IgG (FcγRs). Remarkably, HCMV expresses the RL11-encoded gp34 and UL119-118-encoded gp68 type I transmembrane glycoproteins which bind Fcγ with nanomolar affinity. Using a newly developed FcγR activation assay, we tested if the HCMV-encoded Fcγ binding proteins (HCMV FcγRs) interfere with individual host FcγRs. In absence of gp34 or/and gp68, HCMV elicited a much stronger activation of FcγRIIIA/CD16, FcγRIIA/CD32A and FcγRI/CD64 by polyclonal HCMV-immune IgG as compared to wildtype HCMV. gp34 and gp68 co-expression culminates in the late phase of HCMV replication coinciding with the emergence of surface HCMV antigens triggering FcγRIII/CD16 responses by polyclonal HCMV-immune IgG. The gp34- and gp68-dependent inhibition of HCMV immune IgG was fully reproduced when testing the activation of primary human NK cells. Their broad antagonistic function towards FcγRIIIA, FcγRIIA and FcγRI activation was also recapitulated in a gain-of-function approach based on humanized monoclonal antibodies (trastuzumab, rituximab) and isotypes of different IgG subclasses. Surface immune-precipitation showed that both HCMV-encoded Fcγ binding proteins have the capacity to bind trastuzumab antibody-HER2 antigen complexes demonstrating simultaneous linkage of immune IgG with antigen and the HCMV inhibitors on the plasma membrane. Our studies reveal a novel strategy by which viral FcγRs can compete for immune complexes against various Fc receptors on immune cells, dampening their activation and antiviral immunity.     

Association between the Pro12Ala polymorphism of PPAR-γ gene and the polycystic ovary syndrome: a meta-analysis of case-control studies

Several studies have been conducted to examine the association between PPAR-γ2 Pro12Ala polymorphism and polycystic ovary syndrome (PCOS), but the results remain inconsistent. To make a more precise estimation of the relationship, a meta-analysis was performed. In the current meta-analysis, a total of 17 case-control studies, including 2176 cases and 2373 controls, were selected. Odds ratios (ORs) and 95% confidence intervals (CIs) for Pro/Ala+Ala/Ala versus Pro/Pro genotype in all population and different nationality groups, and homeostasis model assessment-insulin resistance (HOMA-IR) of different genotype were evaluated. In the overall analysis, significant association between PPAR-γ2 Pro12Ala polymorphism and reduced risk of PCOS was observed (OR=0.75; 95%CI, 0.62-0.91; p=0.003). Stratified analysis showed that significantly strong association was presented only in Europeans (OR=0.74; 95%CI, 0.60-0.90; p=0.003), but not in Asians (OR=0.86; 95%CI, 0.51-1.43; p=0.56). Additionally, carrying the Ala12 allele was not associated with HOMA-IR in PCOS patients (OR=-0.29; 95%CI, -0.82-0.24; p=0.29). This meta-analysis supported that PPAR-γ2 Pro12Ala polymorphism was capable of reducing polycystic ovary syndrome risk in Europeans, but not in Asians.     

Fcγ receptors inhibit mouse and human basophil activation

Besides high-affinity IgE receptors (FcεRI), human basophils express activating (FcγRIIA) and inhibitory (FcγRIIB) low-affinity IgG receptors. IgG receptors (FcγR) were also found on mouse basophils, but not identified. We investigated in this study FcγR and the biological consequences of their engagement in basophils of the two species. We found the following: 1) that mouse basophils also express activating (FcγRIIIA) and inhibitory (FcγRIIB) low-affinity FcγR; 2) that activating FcγR can activate both human and mouse basophils, albeit with different efficacies; 3) that negative signals triggered by inhibitory FcγR are dominant over positive signals triggered by activating FcγR, thus preventing both human and mouse basophils from being activated by IgG immune complexes; 4) that the coengagement of FcεRI with inhibitory and activating FcγR results in a FcγRIIB-dependent inhibition of IgE-induced responses of both human and mouse basophils; 5) that FcγRIIB has a similar dominant inhibitory effect in basophils from virtually all normal donors; and 6) that IL-3 upregulates the expression of both activating and inhibitory FcγR on human basophils from normal donors, but further enhances FcγRIIB-dependent inhibition. FcγR therefore function as a regulatory module, made of two subunits with antagonistic properties, that prevents IgG-induced and controls IgE-induced basophil activation in both mice and humans.     

Association of IL-6 promoter and IFN-γ gene polymorphisms with acute rejection of liver transplantation

Liver transplantation is one of the most important therapies for end-stage liver diseases and is associated with major problems including infections and acute rejection. The outcome of transplantation can be determined by immune responses as a key role in response to the graft. Inflammatory and anti-inflammatory mediators especially cytokines influence the graft microenvironment. Th1 and Th2 immune responses in contrast to regulatory responses cause acute rejection or help graft survival. In this study, we evaluated the gene polymorphisms of IL-6 G-174C, TGF-β T + 869C, IL-4 C-590T, and IFN-γ T + 874A cytokines in liver transplant patients. ARMS-PCR method was used to characterize IL-6 G-174C, TGF-β T + 869C and IFN-γ T + 874A polymorphisms and PCR-RFLP using AvaII restriction enzyme was done for IL-4 C-590T characterization in 70 liver transplant patients. Acute rejection episodes were diagnosed according to standard criteria. The analysis of the results showed that IL-6-174 GG genotype ( P = 0.009, OR = 4.333, 95% CI = 1.043–18.000), IL-6-174G allele (P = 0.011, OR = 5.273, 95% CI = 1.454–19.127) was more frequent and IFN-γ +874 TT genotype was less frequent (P = 0.043, OR = 0.143, 95% CI = 0.0118–1.190) in acute rejection than in non-rejection patients. TGF-β T + 869C and IL-4 C-590T frequencies were not significantly different (P > 0.05). According to the results, it can be conclude that IL-6 G-174C and IFN-γ T + 874A gene polymorphisms have predictive values for acute rejection after liver transplantation. High producer genotype of IL-6 is a genetic risk factor and IFN-γ is a protective factor for acute rejection development.     

Management of elderly patients with a non-ST-segment-elevation acute coronary syndrome

Elderly patients with an acute coronary syndrome are underrepresented in randomised controlled trials. Neither the European Society of Cardiology nor the American Heart Association/American College of Cardiology acute coronary syndrome guidelines provide specific recommendations for elderly patients. However, elderly patients are at higher thrombotic and bleeding risk compared with younger patients leading to difficulties in choosing the optimal treatment. In this review, we discuss the uncertainties we encounter in treating elderly patients with non-ST-elevation acute coronary syndrome and suggest treatment options based on the existing literature.     

Characterization of conformational deformation-coupled interaction between immunoglobulin G1 Fc glycoprotein and a low-affinity Fcγ receptor by deuteration-assisted small-angle neutron scattering

A recently developed integrative approach combining varied types of experimental data has been successfully applied to three-dimensional modelling of larger biomacromolecular complexes. Deuteration-assisted small-angle neutron scattering (SANS) plays a unique role in this approach by making it possible to observe selected components in the complex. It enables integrative modelling of biomolecular complexes based on building-block structures typically provided by X-ray crystallography. In this integrative approach, it is important to be aware of the flexible properties of the individual building blocks. Here we examine the ability of SANS to detect a subtle conformational change of a multidomain protein using the Fc portion of human immunoglobulin G (IgG) interacting with a soluble form of the low-affinity Fcγ receptor IIIb (sFcγRIIIb) as a model system. The IgG-Fc glycoprotein was subjected to SANS in the absence and presence of 75%-deuterated sFcγRIIIb, which was matched out in D₂O solution. This inverse contrast-matching technique enabled selective observation of SANS from IgG-Fc, thereby detecting its subtle structural deformation induced by the receptor binding. The SANS data were successfully interpreted by considering previously reported crystallographic data and an equilibrium between free and sFcγRIIIb-bound forms. Our SANS data thus demonstrate the applicability of SANS in the integrative approach dealing with biomacromolecular complexes composed of weakly associated building blocks with conformational plasticity.     

IgG Fc variant cross-reactivity between human and rhesus macaque FcγRs

Non-human primate (NHP) studies are often an essential component of antibody development efforts before human trials. Because the efficacy or toxicity of candidate antibodies may depend on their interactions with Fcγ receptors (FcγR) and their resulting ability to induce FcγR-mediated effector functions such as antibody-dependent cell-meditated cytotoxicity and phagocytosis (ADCP), the evaluation of human IgG variants with modulated affinity toward human FcγR is becoming more prevalent in both infectious disease and oncology studies in NHP. Reliable translation of these results necessitates analysis of the cross-reactivity of these human Fc variants with NHP FcγR. We report evaluation of the binding affinities of a panel of human IgG subclasses, Fc amino acid point mutants and Fc glycosylation variants against the common allotypes of human and rhesus macaque FcγR by applying a high-throughput array-based surface plasmon resonance platform. The resulting data indicate that amino acid variation present in rhesus FcγRs can result in disrupted, matched, or even increased affinity of IgG Fc variants compared with human FcγR orthologs. These observations emphasize the importance of evaluating species cross-reactivity and developing an understanding of the potential limitations or suitability of representative in vitro and in vivo models before human clinical studies when either efficacy or toxicity may be associated with FcγR engagement.     

Association of Fcγ Receptor IIB Polymorphism with Cryptococcal Meningitis in HIV-Uninfected Chinese Patients

Background

As important regulators of the immune system, the human Fcγ receptors (FcγRs) have been demonstrated to play important roles in the pathogenesis of various infectious diseases. The aim of the present study was to identify the association between FCGR polymorphisms and cryptococcal meningitis.

Methodology/Principal Findings

In this case control genetic association study, we genotyped four functional polymorphisms in low-affinity FcγRs, including FCGR2A 131H/R, FCGR3A 158F/V, FCGR3B NA1/NA2, and FCGR2B 232I/T, in 117 patients with cryptococcal meningitis and 190 healthy controls by multiplex SNaPshot technology. Among the 117 patients with cryptococcal meningitis, 59 had predisposing factors. In patients with cryptococcal meningitis, the FCGR2B 232I/I genotype was over-presented (OR = 1.652, 95% CI [1.02–2.67]; P = 0.039) and the FCGR2B 232I/T genotype was under-presented (OR = 0.542, 95% CI [0.33–0.90]; P = 0.016) in comparison with control group. In cryptococcal meningitis patients without predisposing factors, FCGR2B 232I/I genotype was also more frequently detected (OR = 1.958, 95% CI [1.05–3.66]; P = 0.033), and the FCGR2B 232I/T genotype was also less frequently detected (OR = 0.467, 95% CI [0.24–0.91]; P = 0.023) than in controls. No significant difference was found among FCGR2A 131H/R, FCGR3A 158F/V, and FCGR3B NA1/NA2 genotype frequencies between patients and controls.

Conclusion/Significance

We found for the first time associations between cryptococcal meningitis and FCGR2B 232I/T genotypes, which suggested that FcγRIIB might play an important role in the central nervous system infection by Cryptococcus in HIV-uninfected individuals.     

Long-term outcomes of a Caucasian cohort presenting with acute coronary syndrome and/or out-of-hospital cardiac arrest caused by coronary spasm

Background

Coronary artery spasm may be the underlying mechanism in up to 10% of cases of acute coronary syndrome (ACS) and sudden cardiac death. Asian individuals exhibit a 3-times greater incidence of spasm than Caucasians; this is likely due to different types of mechanisms. Consequently, solid data is limited about the long-term prognosis in Caucasian patients presenting with ACS and/or out-of-hospital cardiac arrest (OHCA) caused by coronary spasm.

Methods

Between 2002 and 2015, thirty Caucasian patients with coronary artery spasm presenting with ACS (N = 29) and/or OHCA (N = 11) were enrolled in this prospective registry. Follow-up, consisting of regular outpatient visits, was conducted with a mean follow-up period of 7.5 ± 3.3 years. Outcomes included presence of stable angina pectoris, recurrence of ACS, occurrence of implantable cardioverter defibrillator (ICD) shocks and death.

Results

The majority of patients (60%) remained asymptomatic during the entire follow-up period. At the end of the follow-up period only 3 patients still experienced stable angina (10%). Only 2 patients (7%) had a recurrent cardiac event, in which the ICD provided appropriate shock therapy. Half of the patients treated with stenting (N = 6), required re-interventions.

Conclusion

Coronary spasm with ACS and/or OHCA in a Caucasian patient cohort has a relatively benign prognosis in the majority of patients in long-term follow-up, if treated appropriately with medical therapy. Both the role of ICD in OHCA secondary to coronary spasm, and the efficacy of stenting to treat vasospastic angina, warrant further study in large-sized prospective clinical trials.

     

Association between C′3 phenotypes and various diseases

Summary The distribution of C3 phenotypes in leprosy, rheumatism, diabetes, hyperlipedemia and hepatitis were studied. There was a significant excess of FF-phenotypes in patients with rheumatic factor while in hepatitis the SS-phenotype was significantly lower and a relatively high frequency of FF was stated. The results are discussed.

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Zusammenfassung Es wurde die Verteilung der C3-Phänotypen bei Lepra-, Rheuma-, Diabetes-, Hyperlipidämie- und Hepatitispatienten untersucht. Hierbei wurde ein signifikanter überschuß an FF-Phänotypen bei Patientent mit Rheumafaktor festgestellt, während bei Hepatitis der SS-Phänotyp signifikant niedrig war und sich eine relativ hohe Frequenz von FF zeigte. Die Ergebnisse werden diskutiert.

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Formed part of a thesis of the senior author submitted to the Universität Mainz.

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Alexander von Humboldt Fellow.     

Synergy between TLR3 and IL-18 promotes IFN-γ dependent TRAIL expression in human liver NK cells

Natural killer (NK) cells are a component of innate immunity against viral infections through their rapid cytotoxic activity and cytokine production. However, intra-hepatic NK cells’ ability to respond to virus is still mostly unknown. Our results show that the synthetic dsRNA polyinosinic–polycytidylic acid (poly I:C), a mimic of a common product of viral infections, activates NK cells directly in the context of cytokines found in the liver, i.e.: poly I:C plus inflammatory cytokines (IL-18, IL-12, and IL-2) induced NK cell IFN-γ production and TRAIL expression, and anti-inflammatory cytokines (TGF-β and IL-10) inhibit NK cell IFN-γ production. Neutralization of IFN-γ blocks poly I:C plus inflammatory cytokines-induced NK cell TRAIL expression, suggesting that IFN-γ is an autocrine differentiation factor for these cells. A better understanding of the intra-hepatic NK cell activation against viral infection may help in the design of therapies and vaccines for the control of viral hepatitis.     

Transient expression of human interleukin-2 and interferon-γ genes is regulated by interaction between distinct cell subsets

The level of transient expression of human IL-2 and IFN-γ genes, we show, is regulated by dynamic interaction between two functionally distinct cell populations. One is able to express these genes, while the other, bearing one of several specific surface markers, actively inhibits their expression. Defined cell subsets were isolated from PBMC and tonsil cells using immunomagnetic beads coated with monoclonal antibodies directed against surface markers. Depletion of CD8, CD11a (Leu15), or Leu8 subsets led to a pronounced superinduction of IL-2 and IFN-γ gene expression when the remaining cell population was stimulated with mitogen (PHA) or antigen (SEB). Thus, a 10-fold increase in production of IFN-γ was observed after removal of CD11a (Leu15) cells constituting only a small percentage of the total cell population. By contrast, depletion of cells expressing CD19, a B cell marker, did not yield any superinduction. Conversely, CD8, CD11a (Leu15), or Leu8 cell subsets, but not CD19 cells, each inhibited the induction of IL-2 and IFN-γ gene expression almost completely in depleted or total cell populations from which they were derived. Gene expression occurring within one cell subset could be effectively inhibited by cells from a second subset. Introduction of inhibitory cells (Leu8) into a population that actively expressed IL-2 and IFN-γ mRNA resulted in an immediate cessation of gene expression. This suppression involves a soluble mediator, since the culture medium in which such cells were activated exerted a similarly effective inhibition.     

Ligation of macrophage Fcγ receptors recapitulates the gene expression pattern of vulnerable human carotid plaques

Stroke is a leading cause of death in the United States. As ～60% of strokes result from carotid plaque rupture, elucidating the mechanisms that underlie vulnerability is critical for therapeutic intervention. We tested the hypothesis that stable and vulnerable human plaques differentially express genes associated with matrix degradation. Examination established that femoral, and the distal region of carotid, plaques were histologically stable while the proximal carotid plaque regions were vulnerable. Quantitative RT-PCR was used to compare expression of 22 genes among these tissues. Distal carotid and femoral gene expression was not significantly different, permitting the distal carotid segments to be used as a paired control for their corresponding proximal regions. Analysis of the paired plaques revealed differences in 16 genes that impact plaque stability: matrix metalloproteinases (MMP, higher in vulnerable), MMP modulators (inhibitors: lower, activators: higher in vulnerable), activating Fc receptors (FcγR, higher in vulnerable) and FcγR signaling molecules (higher in vulnerable). Surprisingly, the relative expression of smooth muscle cell and macrophage markers in the three plaque types was not significantly different, suggesting that macrophage distribution and/or activation state correlates with (in)stability. Immunohistochemistry revealed that macrophages and smooth muscle cells localize to distinct and non-overlapping regions in all plaques. MMP protein localized to macrophage-rich regions. In vitro, treatment of macrophages with immune complexes, but not oxidized low density lipoprotein, C-reactive protein, or TNF-α, induced a gene expression profile similar to that of the vulnerable plaques. That ligation of FcγR recapitulates the pattern of gene expression in vulnerable plaques suggests that the FcγR → macrophage activation pathway may play a greater role in human plaque vulnerability than previously appreciated.