TIM1 haplotype may control the disease progression to AIDS in a HIV-1-infected female cohort in Thailand

Disposable electrochemical immunoplatform to shed light on the role of the multifunctional glycoprotein TIM-1 in cancer cells invasion

Detecting overexpression of cancer biomarkers is an excellent tool for diagnostic/prognostic and follow-up of patients with cancer or their response to treatment. This work illustrates the relevance of interrogating the levels of T-cell immunoglobulin and mucin domain 1 (TIM-1) protein as a diagnostic/prognostic biomarker of high-prevalence breast and lung cancers by using an amperometric disposable magnetic microparticles-assisted immunoplatform. The developed method integrates the inherent advantages of carboxylic acid-functionalized magnetic beads (HOOC-MBs) as pre-concentrator support and the amperometric transduction at screen-printed carbon electrodes (SPCEs). The immunoplatform involves a sandwich-type immunoassay assembled on HOOC-MBs through the specific capture/labeling of TIM-1 using capture antibodies and horseradish peroxidase (HRP)-conjugated biotinylated detection antibodies as biorecognition elements. The magnetic immunoconjugates were confined onto the working electrode (WE) surface of the SPCEs for amperometric detection using the hydroquinone/hydrogen peroxide/HRP (HQ/H2O2/HRP) redox system. The method allows the selective detection of TIM-1 protein over the 87-7500 pg mL-1 concentration range in only 45 min, with a limit of detection of 26 pg mL-1. The developed bioplatform was successfully applied to the analysis of breast and lung cancer cell extracts, providing the first quantitative results of the target glycoprotein in these types of samples.

Relationship of Severity of Hepatitis A with Polymorphisms in Hepatitis A Virus Cellular Receptor 1 (HAVCR1) Gene

INTRODUCTION AND AIM

HAVCR1 protein is the cellular receptor for hepatitis A virus (HAV). Genetic polymorphism in this gene may alter the outcome of HAV infection. In a previous study, a 6-amino acid insertion (157insMTTTVP) in HAVCR1 gene was associated with more severe disease. We decided to investigate this association further.

MATERIAL AND METHODS

We sequenced exon 4 of the HAVCR1 gene in patients with clinical hepatitis A attending our institution, and a group of healthy controls in a disease-endemic setting in India. Frequencies of different haplotypes of a genomic region with two overlapping insertion-deletion polymorphisms (indels; rs141023871 and rs139041445) were compared between patients and controls, as well as between patients with and without a severe form of disease (liver failure).

RESULTS

The gene had three haplotypes in the region of interest - a short form, an intermediate-form with a 5-amino acid 157insMTTVP insertion and a long-form with a 6-amino acid 157insMTTTVP insertion. The allele frequency (29/150 [19%] vs. 43/146 [29%]; p = ns) and haplotype frequency (29/75 [39%] vs. 39/73 [53%]; p = ns) of the 157insMTTTVP variant were similar in hepatitis A patients and healthy controls (30%). Further, the allele frequency (12/58 [21%] vs. 17/92 [18%]; p = ns) and haplotype frequency (12/29 [41%] vs.17/46 [37%]; p = ns) of the longest variant were also similar in patients with severe and mild disease.

DISCUSSION

In the study population, the 157insMTTTVP variant of HAVCR1 gene was not associated with more severe outcome of HAV infection. Further studies in other populations around the world are needed to assess the relation of this genetic variation with disease outcome.

Benzyl-2-Acetamido-2-Deoxy-α-d-Galactopyranoside Increases Human Immunodeficiency Virus Replication and Viral Outgrowth Efficacy In Vitro

Glycosylation of host and viral proteins is an important posttranslational modification needed to ensure correct function of glycoproteins. For this reason, we asked whether inhibition of O-glycosylation during human immunodeficiency virus (HIV) in vitro replication could affect HIV infectivity and replication rates. We used benzyl-2-acetamido-2-deoxy-α-d-galactopyranoside (BAGN), a compound that has been widely used to inhibit O-glycosylation in several cell lines. Pretreatment and culture of PHA-blast target cells with BAGN increased the percentage of HIV-infected cells (7.6-fold, p = 0.0115), the per-cell amount of HIV p24 protein (1.3-fold, p = 0.2475), and the viral particles in culture supernatants (7.1-fold, p = 0.0029) compared to BAGN-free cultures. Initiating infection with virus previously grown in the presence of BAGN further increased percentage of infected cells (30-fold, p < 0.0001), intracellular p24 (1.5-fold, p = 0.0433), and secreted viral particles (74-fold, p < 0.0001). BAGN-treated target cells showed less CD25 and CCR5 expression, but increased HLA-DR surface expression, which positively correlated with the number of infected cells. Importantly, BAGN improved viral outgrowth kinetics in 66% of the samples tested, including samples from HIV controllers and subjects in whom no virus could be expanded in the absence of BAGN. Sequencing of the isolated virus indicated no skewing of viral quasi-species populations when compared to BAGN-free culture conditions. BAGN also increased virus production in the ACH2 latency model when used together with latency-reversing agents. Taken together, our results identify BAGN treatment as a simple strategy to improve viral outgrowth in vitro and may provide novel insights into host restriction mechanisms and O-glycosylation-related therapeutic targets for HIV control strategies.

C5a/C5aR pathway accelerates renal ischemia-reperfusion injury by downregulating PGRN expression

Recent reports indicate that the complement C5a/C5aR pathway and progranulin (PGRN) deficiency both contribute to ischemia-reperfusion (IR)-induced acute kidney injury. However, the underlying relationship between the C5a/C5aR signaling pathway and PGRN expression during acute kidney injury is poorly understood. In this study, we showed that C5aR expression was significantly upregulated after renal IR, and that C5aR deficiency led to a marked increase in PGRN expression and a significant reduction in tubular damage and production of inflammatory cytokines. In accordance with these results, recombinant C5a caused downregulation of PGRN protein and mRNA levels in renal tubular epithelial cells (HK-2 cells), which could be negated by disruption of C5a/C5aR signaling by the C5aR antagonist, as confirmed by immunofluorescence, western blotting, and quantitative real-time PCR. Moreover, C5aR deficiency resulted in attenuated NF-κB expression 24h after IR, and recombinant C5a potentiated TNFα-induced NF-κB activation in HK-2 cells. Inhibition of NF-κB activation reversed C5a-induced downregulation of PGRN expression. Our results show for the first time that the complement C5a/C5aR pathway aggravates IR-induced acute kidney injury by suppressing PGRN expression and confirm that suppression of PGRN expression is associated with increased NF-κB activation induced by C5a.

A 6-amino acid insertion/deletion polymorphism in the mucin domain of TIM-1 confers protections against HIV-1 infection

We investigated whether a 6-amino acid insertion/deletion polymorphism in the mucin domain of TIM-1 (T-cell immunoglobulin and mucin domain 1), modulates susceptibility to HIV-1 infection. The polymorphism was genotyped in three case/control cohorts of HIV-1 exposed seronegative individuals (HESN) and HIV-1 infected subjects from Italy, Peru, and Colombia; data from a Thai population were retrieved from the literature. Across all cohorts, homozygosity for the short TIM-1 allele was more common in HESNs than in HIV-1 infected subjects. A meta-analysis of the four association analyses yielded a p value of 0.005. In vitro infection assays of CD4+ T lymphocytes indicated that homozygosity for the short allele is associated with lower rate of HIV-1 replication. These results suggest that the deletion allele protects from HIV-1 infection with a recessive effect.

Conjugated Bilirubin Differentially Regulates CD4+ T Effector Cells and T Regulatory Cell Function through Outside-In and Inside-Out Mechanisms: The Effects of HAV Cell Surface Receptor and Intracellular Signaling

We recently reported an immune-modulatory role of conjugated bilirubin (CB) in hepatitis A virus (HAV) infection. During this infection the immune response relies on CD4+ T lymphocytes (TLs) and it may be affected by the interaction of HAV with its cellular receptor (HAVCR1/TIM-1) on T cell surface. How CB might affect T cell function during HAV infection remains to be elucidated. Herein, in vitro stimulation of CD4+ TLs from healthy donors with CB resulted in a decrease in the degree of intracellular tyrosine phosphorylation and an increase in the activity of T regulatory cells (Tregs) expressing HAVCR1/TIM-1. A comparison between CD4+ TLs from healthy donors and HAV-infected patients revealed changes in the TCR signaling pathway relative to changes in CB levels. The proportion of CD4+CD25+ TLs increased in patients with low CB serum levels and an increase in the percentage of Tregs expressing HAVCR1/TIM-1 was found in HAV-infected patients relative to controls. A low frequency of 157insMTTTVP insertion in the viral receptor gene HAVCR1/TIM-1 was found in patients and controls. Our data revealed that, during HAV infection, CB differentially regulates CD4+ TLs and Tregs functions by modulating intracellular pathways and by inducing changes in the proportion of Tregs expressing HAVCR1/TIM-1.

APOBEC3H polymorphisms and susceptibility to HIV-1 infection in an Indian population

Human APOBEC3H (A3H) is a member of APOBEC cytidine deaminase family intensively constraining the HIV-1 replication. A3H is known to be polymorphic with different protein stability and anti-HIV-1 activity in vitro. We recently reported that A3H haplotypes composed of two functional polymorphisms, rs139292 (N15del) and rs139297 (G105R), were associated with the susceptibility to HIV-1 infection in Japanese. To confirm the association of A3H and HIV-1 infection in another ethnic group, a total of 241 HIV-1-infected Indian individuals and ethnic-matched 286 healthy controls were analyzed for the A3H polymorphisms. The frequency of 15del allele was high in the HIV-1-infected subjects as compared with the controls (0.477 vs 0.402, odds ratio (OR)=1.36, P=0.014). Haplotype analysis showed that the frequencies of 15del-105R was high (0.475 vs 0.400, OR=1.36, permutation P=0.037) in the HIV-1-infected subjects, confirming the association of A3H polymorphisms with the susceptibility to HIV-1 infection.

T-cell immunoglobulin and mucin domain 1 deficiency eliminates airway hyperreactivity triggered by the recognition of airway cell death

BACKGROUND

Studies of asthma have been limited by a poor understanding of how nonallergic environmental exposures, such as air pollution and infection, are translated in the lung into inflammation and wheezing.

OBJECTIVE

Our goal was to understand the mechanism of nonallergic asthma that leads to airway hyperreactivity (AHR), a cardinal feature of asthma independent of adaptive immunity.

METHOD

We examined mouse models of experimental asthma in which AHR was induced by respiratory syncytial virus infection or ozone exposure using mice deficient in T-cell immunoglobulin and mucin domain 1 (TIM1/HAVCR1), an important asthma susceptibility gene.

RESULTS

TIM1(-/-) mice did not have airways disease when infected with RSV or when repeatedly exposed to ozone, a major component of air pollution. On the other hand, the TIM1(-/-) mice had allergen-induced experimental asthma, as previously shown. The RSV- and ozone-induced pathways were blocked by treatment with caspase inhibitors, indicating an absolute requirement for programmed cell death and apoptosis. TIM-1-expressing, but not TIM-1-deficient, natural killer T cells responded to apoptotic airway epithelial cells by secreting cytokines, which mediated the development of AHR.

CONCLUSION

We defined a novel pathway in which TIM-1, a receptor for phosphatidylserine expressed by apoptotic cells, drives the development of asthma by sensing and responding to injured and apoptotic airway epithelial cells.

Chronic hepatitis B and C co-infection increased all-cause mortality in HAART-naive HIV patients in Northern Thailand

A total of 755 highly active antiretroviral therapy (HAART)-naive HIV-infected patients were enrolled at a government hospital in Thailand from 1 June 2000 to 15 October 2002. Census date of survival was on 31 October 2004 or the date of HAART initiation. Of 700 (92·6%) patients with complete data, the prevalence of hepatitis B virus (HBV) surface antigen and anti-hepatitis C virus (HCV) antibody positivity was 11·9% and 3·3%, respectively. Eight (9·6%) HBV co-infected patients did not have anti-HBV core antibody (anti-HBcAb). During 1166·7 person-years of observation (pyo), 258 (36·9%) patients died [22·1/100 pyo, 95% confidence interval (CI) 16·7–27·8]. HBV and probably HCV co-infection was associated with a higher mortality with adjusted hazard ratios (aHRs) of 1·81 (95% CI 1·30–2·53) and 1·90 (95% CI 0·98–3·69), respectively. Interestingly, HBV co-infection without anti-HBc Ab was strongly associated with death (aHR 6·34, 95% CI 3·99–10·3). The influence of hepatitis co-infection on the natural history of HAART-naive HIV patients requires greater attention.

Lineage-specific evolution of T-cell immunoglobulin and mucin domain 1 gene in the primates

T-cell immunoglobulin domain and mucin domain containing protein 1 (TIM1), also known as a cellular receptor for hepatitis A virus (HAVCR1) or a molecule induced by ischemic injury in the kidney (KIM1), is involved in the regulation of immune responses. We investigated a natural selection history of TIM1 by comparative sequencing analysis in 24 different primates. It was found that TIM1 had become a pseudogene in multiple lineages of the New World monkey. We also investigated T cell lines originated from four different New World monkey species and confirmed that TIM1 was not expressed at the mRNA level. On the other hand, there were ten amino acid sites in the Ig domain of TIM1 in the other primates, which were suggested to be under positive natural selection. In addition, mucin domain of TIM1 was highly polymorphic in the Old World monkeys, which might be under balanced selection. These data suggested that TIM1 underwent a lineage-specific evolutionary pathway in the primates.

TIM polymorphisms--genetics and function

The transmembrane immunoglobulin and mucin domain (TIM) family was identified more than a decade ago. Although the founding member of the family was first described in a rat model of ischemia-reperfusion injury, much of the recent interest in the TIM family members has focused on their potential roles in immunity. There are now a large number of genetic studies that have investigated the possible association of various TIM1 and TIM3 polymorphisms with different diseases. Here, we review this body of literature, and highlight some of the most interesting studies.

Novel roles for TIM-1 in immunity and infection

T cell, immunoglobulin domain and mucin domain-1 (TIM-1) is the nominant member of a small family of related proteins that regulate immune cell activities. TIM-1 was initially characterized in a mouse congenic analysis of Th2 T cell responses and related pathology. Data accumulated to date suggest that TIM-1 regulates effector T cell function, and may play distinct roles in the activities of B cells, invariant NKT cells and epithelial cells. In addition, a variety of ligands for TIM-1 have been proposed. In this review I discuss recent data that have accumulated on the function of TIM-1, propose a model to explain how TIM-1 regulates effector T cell activity through recognition of distinct ligands, and review others functions of this increasingly fascinating protein. Of considerable interest are the novel findings that TIM-1 mediates virus entry and virulence.

A polymorphism in TIM1 is associated with susceptibility to severe hepatitis A virus infection in humans

During infection with the hepatitis A virus (HAV), most patients develop mild or asymptomatic disease. However, a small number of patients develop serious, life-threatening hepatitis. We investigated this variability in disease severity by examining 30 Argentinean patients with HAV-induced acute liver failure in a case-control, cross-sectional, observational study. We found that HAV-induced severe liver disease was associated with a 6-amino-acid insertion in TIM1/HAVCR1 (157insMTTTVP), the gene encoding the HAV receptor. This polymorphism was previously shown to be associated with protection against asthma and allergic diseases and with HIV progression. In binding assays, the TIM-1 protein containing the 157insMTTTVP insertion polymorphism bound HAV more efficiently. When expressed by human natural killer T (NKT) cells, this long form resulted in greater NKT cell cytolytic activity against HAV-infected liver cells, compared with the shorter TIM-1 protein without the polymorphism. To our knowledge, the 157insMTTTVP polymorphism in TIM1 is the first genetic susceptibility factor shown to predispose to HAV-induced acute liver failure. Furthermore, these results suggest that HAV infection has driven the natural selection of shorter forms of the TIM-1 protein, which binds HAV less efficiently, thereby protecting against severe HAV-induced disease, but which may predispose toward inflammation associated with asthma and allergy.