Abstract

BackgroundWe have previously reported that interleukin-10 (IL-10) deficient dendritic cells (DCs) are potent antigen presenting cells that induced elevated protective immunity against Chlamydia. To further investigate the molecular and biochemical mechanism underlying the superior immunostimulatory property of IL-10 deficient DCs we performed proteomic analysis on protein profiles from Chlamydia-pulsed wild-type (WT) and IL-10−/− DCs to identify differentially expressed proteins with immunomodulatory properties.ResultsThe results showed that alpha enolase (ENO1), a metabolic enzyme involved in the last step of glycolysis was significantly upregulated in Chlamydia-pulsed IL-10−/− DCs compared to WT DCs. We further studied the immunoregulatory role of ENO1 in DC function by generating ENO1 knockdown DCs, using lentiviral siRNA technology. We analyzed the effect of the ENO1 knockdown on DC functions after pulsing with Chlamydia. Pyruvate assay, transmission electron microscopy, flow cytometry, confocal microscopy, cytokine, T-cell activation and adoptive transfer assays were also used to study DC function. The results showed that ENO1 knockdown DCs had impaired maturation and activation, with significant decrease in intracellular pyruvate concentration as compared with the Chlamydia-pulsed WT DCs. Adoptive transfer of Chlamydia-pulsed ENO1 knockdown DCs were poorly immunogenic in vitro and in vivo, especially the ability to induce protective immunity against genital chlamydia infection. The marked remodeling of the mitochondrial morphology of Chlamydia-pulsed ENO1 knockdown DCs compared to the Chlamydia-pulsed WT DCs was associated with the dysregulation of translocase of the outer membrane (TOM) 20 and adenine nucleotide translocator (ANT) 1/2/3/4 that regulate mitochondrial permeability. The results suggest that an enhanced glycolysis is required for efficient antigen processing and presentation by DCs to induce a robust immune response.ConclusionsThe upregulation of ENO1 contributes to the superior immunostimulatory function of IL-10 deficient DCs. Our studies indicated that ENO1 deficiency causes the reduced production of pyruvate, which then contributes to a dysfunction in mitochondrial homeostasis that may affect DC survival, maturation and antigen presenting properties. Modulation of ENO1 thus provides a potentially effective strategy to boost DC function and promote immunity against infectious and non-infectious diseases.

Highlights

  • We have previously reported that interleukin-10 (IL-10) deficient dendritic cells (DCs) are potent antigen presenting cells that induced elevated protective immunity against Chlamydia

  • To rule out the possibility that we were working with normally overly expressed proteins, we evaluated the biological significance of the proteins, when we evaluated the metabolism related proteins by Western Blotting, Alpha enolase (ENO1) which is a key glycolytic enzyme was remarkably upregulated in IL-10−/− DCs compared to WT DCs (Fig. 1b)

  • In our ongoing study of the function of IL-10−/− DCs during Chlamydia infection, we observed using 2-DIGE proteomics, the differential expression of the protein ENO1, which was up regulated in IL-10−/− DCs compared to WT DCs

Read more

Summary

Introduction

We have previously reported that interleukin-10 (IL-10) deficient dendritic cells (DCs) are potent antigen presenting cells that induced elevated protective immunity against Chlamydia. Chlamydia trachomatis genital infection is the most frequently reported bacterial sexually transmitted infection in the United States [1]. In a recent study about 20% of PID and 29% of TFI in women aged 16–44 years was attributed to C. trachomatis infections [3, 4]. Preventive strategies proposed against C. trachomatis include increased screening with mass treatment [5, 6]. Recent clinical and epidemiological data suggests that the vaccine strategy would be the most reliable and cost effective preventive method with the greatest potential impact in the control of C. trachomatis infections and its associated complications in the human population [7, 8]. There is no human vaccine available for C. trachomatis infections; the development of an effective vaccine against C. trachomatis has been a challenging task due to the incomplete understanding of the complex immunological processes associated with chlamydial infection

Methods
Results
Discussion
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call