Plasma MicroRNA Signature Panel Predicts the Immune Response After Antiretroviral Therapy in HIV-Infected Patients.

Background: Approximately 10-40% of people with human immunodeficiency virus (HIV) infection are unable to obtain successful improvements in immune function after antiretroviral therapy (ART). These patients are at greater risk of developing non-acquired immunodeficiency syndrome (AIDS)-related conditions, with the accompanying increased morbidity and mortality. Discovering predictive biomarkers can help to identify patients with a poor immune response earlier and provide new insights into the mechanisms of this condition. Methods: A total of 307 people with HIV were enrolled, including 110 immune non-responders (INRs) and 197 immune responders (IRs). Plasma samples were taken before ART, and quantities of plasma microRNAs (miRNAs) were determined using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). Candidate biomarkers were established through four phases: discovery, training, validation, and blinded test. Binary logistic regression was used to analyze the combined predictive capacity of the identified miRNAs. The effect of one miRNA, miR-16-5p, on T cell function was assessed in vitro. Results: Expression of five miRNAs (miR-580, miR-627, miR-138-5p, miR-16-5p, and miR-323-3p) was upregulated in the plasma of INRs compared with that in IRs. Expression of these miRNAs was negatively correlated with both CD4+ T cell counts and the increase in the proportion of CD4+ T cells after one year of ART. These five miRNAs were combined in a predictive model, which could effectively identify INRs or IRs. Furthermore, we found that miR-16-5p inhibits CD4+ T cell proliferation by regulating calcium flux. Conclusion: We established a five-miRNA panel in plasma that accurately predicts poor immune response after ART, which could inform strategies to reduce the incidence of this phenomenon and improve the clinical management of these patients.

CTL immunogenicity of Rv3615c antigen and diagnostic performances of an ESAT-6/CFP-10/Rv3615c antigen cocktail for Mycobacterium tuberculosis infection.

T cell immune responses have played pivotal roles in host immune protection against Mycobacterium tuberculosis (MTB) infection. MTB specific antigen, Rv3615c (EspC), was identified to be as immunodominant as the well-known ESAT-6 and CFP-10, and has brought promising expectations to more sensitive T-cell based diagnosis and vaccine development. However, limited knowledge about the immunogenicity and diagnostic values of this antigen has restricted its application in clinical practice. Herein, the Rv3615c antigen was identified as a robust CTL immunoantigen with broadly cross-human leucocyte antigen (HLA) allele recognized peptides which may contribute to the broad recognition of Rv3615c antigen among the population. A three-antigen-cocktail (3-Ag-cocktail) comprising of ESAT-6, CFP-10 and Rv3615c was investigated in a multicenter, randomized and double-blinded study to evaluate its clinical diagnostic performances. A significantly improved sensitivity was demonstrated against the 3-Ag-cocktail compared with that against ESAT-6 and CFP-10. Both responsive magnitude and sensitivity were significantly lower in patients concurrently suffering from cancer, indicating its restriction in diagnosis of immunocomprised patients. In conclusion, inclusion of the Rv3615c antigen with multiple HLA restricted CTL epitopes would benefit the T-cell based diagnosis of MTB infection.

Interaction of IFNλR1 with TRAF6 regulates NF-κB activation and IFNλR1 stability.

IFNλR1 is a member of the class II cytokine receptor family, and it associates with IL-10R2 to form a functional receptor complex, IFNλR. This receptor complex transduces signals from IFNλs (IFNλ1, IFNλ2, and IFNλ3), promoting antiviral and antiproliferative activities similar to those of type I IFNs. In an effort to further understand signal transduction through IFNλR1, we used bioinformatics analysis and identified a tumor necrosis factor receptor-associated factor 6 (TRAF6)-binding motif in the intracellular domain of IFNλR1. In subsequent immunoprecipitation and GST pull-down assays, IFNλR1 was shown to immunoprecipitate with TRAF6 and was pulled down by GST-TRAF6. Endogenous IFNλR1 and TRAF-6 interaction implies that these proteins really interact in the cells. This interaction was abrogated upon mutation of the TRAF6-binding motif in IFNλR1. Furthermore, the interaction between IFNλR1 and TRAF6 inhibited TRAF6-induced NF-κB activation, likely due to a reduction in TRAF6 autoubiquitination. Moreover, co-expression of IFNλR1 with TRAF6 significantly increased the stability of IFNλR1, thereby prolonging its half-life and enhancing its steady-state level in cultured cells.

The Ran-binding protein RanBPM can depress the NF-κB pathway by interacting with TRAF6.

Ran-binding protein in microtubule-organizing center (RanBPM) has been reported to interact with the neurotrophin receptors p75NTR and TrkA, meanwhile p75NTR and TrkA can also interact with TRAF6. Whether RanBPM interacts directly with TRAF6 has not yet been established. In this study, using a yeast two-hybrid system and glutathione-S: -transferase pull-down assays, we determined that RanBPM binds to the TRAF6 C-terminus through its SPRY motif. Complex formation between overexpressed RanBPM and TRAF6 was also confirmed with a co-immunoprecipitation assay, laser scanning confocal and fluorescence resonance energy transfer. Additional co-immunoprecipitation experiments verified that endogenous RanBPM and TRAF6 interact in several mammalian cell lines. A series of experiments revealed that RanBPM influences TRAF6 ubiquitination and the TRAF6-triggered NF-κB signaling pathway through RanBPM's interaction with TRAF6. These data suggest that RanBPM participates in gene transcription by binding to TRAF6.