The potential role of human HIV-1 TAT-Interactive Protein 2 levels in the pathogenesis of contact dermatitis

Background/aim: Human HIV-1 TAT interactive protein 2 (HTATIP2/TIP30) is a gene that is extensively expressed in human tissues as well as in tumor tissues. This study aimed to explore the potential role of HTATIP2/TIP30 in contact dermatitis (CD), which is one of the most common inflammatory cutaneous conditions. Materials and methods: This cross-sectional study involved adult patients with acute contact dermatitis who were admitted to the outpatient dermatology clinic of a tertiary hospital and healthy adult volunteers without any cutaneous or systemic diseases. The blood concentration of HTATIP2/TIP30 was measured using ELISA kits. Results: The research sample consisted of 31 patients with CD (18 males, 13 females) and 20 healthy control subjects (14 males, 6 females). The mean ages of the patients with CD and healthy volunteers were 37 and 30 years, respectively (p > 0.05). The mean value of serum HTATIP2/TIP30 levels in patients with CD was 1.65 ng ml­1, which is 0.60 ng ml­1 in the control group (p = 0.02) Conclusion: In this study, serum levels of HTATIP2/TIP30 were statistically significantly higher in patients with CD when compared to healthy controls. This outcome may indicate possible role of HTATIP2/TIP30 in the pathogenesis of CD.

Genome-wide association study of the age of onset of type 1 diabetes reveals HTATIP2 as a novel T cell regulator.

Introduction: Type 1 diabetes, a disorder caused by autoimmune destruction of pancreatic insulin-producing cells, is more difficult to manage when it presents at a younger age. We sought to identify genetic correlates of the age of onset by conducting the first genome-wide association study (GWAS) treating the age of first diagnosis as a quantitative trait. Methods: We performed GWAS with a discovery cohort of 4,014 cases and a replication cohort of 493 independent cases. Genome-wide significant SNPs were mapped to a causal variant by Bayesian conditional analysis and gel shift assay. The causal protein-coding gene was identified and characterized by RNA interference treatment of primary human pan-CD4+ T cells with RNA-seq of the transcriptome. The candidate gene was evaluated functionally in primary cells by CD69 staining and proliferation assays. Results: Our GWAS replicated the known association of the age of diagnosis with the human leukocyte antigen complex (HLA-DQB1). The second signal identified was in an intron of the NELL1 gene on chromosome 11 and fine-mapped to variant rs10833518 (P < 1.54 × 10-9). Homozygosity for the risk allele leads to average age of onset one year earlier. Knock-down of HIV TAT-interacting protein 2 (HTATIP2), but not other genes in the locus, resulted in alterations to gene expression in signal transduction pathways including MAP kinases and PI3-kinase. Higher levels of HTATIP2 expression are associated with increased viability, proliferation, and activation of T cells in the presence of signals from antigen and cytokine receptors. Discussion: This study implicates HTATIP2 as a new type 1 diabetes gene acting via T cell regulation. Larger population sample sizes are expected to reveal additional loci.