Roessing, Anna
(2018)
Controlling dendritic cell function by targeting iron-modulating proteins identified through transcriptional analysis.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Dendritic cells (DC) are key orchestrators of the body’s immune responses. DC control T cell proliferation and differentiation while displaying cognate antigen (Ag) to Ag-specific T cells. DC cytokine secretion is central to the differentiation of T cells into distinct, functional subsets. Stimulation with bacteria-derived molecules such as lipopolysaccharide (LPS) through Toll-like receptor 4 (TLR4) leads to interleukin-12 (IL-12) production by DC and supports T helper type 1 (Th1) generation in interacting cluster of differentiation 4 (CD4+) T cells. Fungal interactions with the Dectin-1 receptor yields IL-6, IL-23, and IL-1β production by DC to mediate Th17 cell polarization. DC, especially those exposed to IL-33, support the generation of IL-5- and IL-13- secreting Th2 cells. However, there are no identified DC-produced cytokines which have been shown to directly underlie Th2 polarization.
The aim of this project was to identify novel genes and signaling pathways by which CD4+ T cell polarization is directed following DC TLR4/ST2 (IL1RL1) ligation. Our preliminary data demonstrated that IL-33 and LPS stimulate the expression of several iron-modulating proteins in DC, such as lipocalin 2 (Lcn2), hemoglobin-α, and cytochrome b5 reductase 3 (Cyb5R3), which act as a previously unappreciated DC nitric oxide (NO) sequestration system. Given these findings, we hypothesized that TLR4/ST2 ligation on DC causes expression of iron-modulating proteins which sequester NO. We found that while TLR4/ST2 receptor ligation on DC induces a NO sequestration system in DC, it involves the expression of hemoglobin-α and potentially other redundant reductase proteins, but not Cyb5R3. Instead, we determined that Cyb5R3 acts as a regulator of DC stimulatory capacity toward CD4+ T cells. Specifically, Cyb5R3 functions as a negative regulator of glycolysis. In Cyb5R3-expressing cells, unstimulated and IL-33-stimulated cells favor oxidative phosphorylation (OXPHOS) while LPS stimulation leads a shift towards glycolysis. Finally, Cyb5R3-deficient DC are both more inflammatory and more stimulatory, producing greater amounts of IL-12 and expressing more stimulatory surface markers, ultimately leading to Th1 cell polarization of naïve T cells, especially upon DC stimulation with LPS.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
30 August 2018 |
| Date Type: |
Publication |
| Defense Date: |
27 April 2018 |
| Approval Date: |
30 August 2018 |
| Submission Date: |
27 July 2018 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
46 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
School of Medicine > Immunology |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
dendritic cells, immunology, signaling, nitric oxide, T cells, Th2, IL-33, interleukin 33, Cyb5R3 |
| Date Deposited: |
30 Aug 2018 20:48 |
| Last Modified: |
30 Aug 2018 20:48 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/35005 |
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