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BACE1 is a novel regulator of Th17 function in EAE

Hernandez Mir, Gerard (2017) BACE1 is a novel regulator of Th17 function in EAE. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Abstract

Th17 cells are implicated in autoimmune disease, including attack of the central nervous system (CNS) in multiple sclerosis. β-site APP-cleaving enzyme 1 (BACE1) is a membrane protease expressed in neurons and astrocytes. BACE1 is best known for its role in promoting neurodegeneration in Alzheimer’s disease by cleaving amyloid precursor protein, although it also plays a critical role in driving myelination of the central and peripheral nervous system. In addition,
BACE1 has been reported to contribute to lesion severity following brain injury, as has IL-17A, although these two molecules have not previously been linked.

Here, we show that in vitro-differentiated BACE1-/- Th17 cells exhibited reduced IL-17A and CD73 production despite regular RORγt upregulation. Expression of IL-17F was mildly reduced while other prototypic Th17 molecules remained unaltered, such as RORγt, IL-23R or GM-CSF. BACE1 regulation of IL-17A and CD73 occurred in a T cell intrinsic manner and its
deficiency impaired the pathogenic function of Th17 cells in different models of EAE. Although affected by BACE1 deficiency, CD73-deficient animals did not exhibit decreased IL-17 production or reduced encephalitogenicity.

Mechanistically, BACE1-deficiency resulted in reduced expression of PTEN and increased production of cAMP by the adenylate cyclase (AC). Concomitantly with imbalanced PTEN, BACE1-/- T cells exhibited higher phosphorylation of Akt upon T cell activation. Accordingly, forskolin-induced activation of the AC as well as PTEN hemideletion or pharmacological blockade phenocopied the findings observed in BACE1-/- Th17 cells.

In summary, our data demonstrate that BACE1 is a novel regulator of Th17 function but does not impact Th17 differentiation. By modulating cAMP and PTEN levels, BACE1 can couple early signaling events, such as T cell activation and Ca2+ signaling, with the specific regulation of IL-17A and CD73 expression in Th17 cells. These findings highlight BACE1 as a novel potential therapeutic target to treat IL-17A-driven autoimmune disorders.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Hernandez Mir, Gerardgeh28@pitt.edugeh28
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Thesis AdvisorMcGeachy, Mandymandymcgeachy@pitt.edu
Committee MemberWiley, Claytonwiley1@pitt.edu
Committee MemberRay, Anuradharaya@pitt.edu
Committee MemberLu, Binfengbinfeng@pitt.edu
Committee MemberTurnquist, Hethhet5@pitt.edu
Date: 14 September 2017
Date Type: Publication
Defense Date: 24 July 2017
Approval Date: 14 September 2017
Submission Date: 16 August 2017
Access Restriction: 3 year -- Restrict access to University of Pittsburgh for a period of 3 years.
Number of Pages: 255
Institution: University of Pittsburgh
Schools and Programs: School of Medicine > Immunology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: T cells Inflammation T cell signaling T cell activation
Date Deposited: 14 Sep 2017 16:10
Last Modified: 14 Sep 2020 05:15
URI: http://d-scholarship.pitt.edu/id/eprint/33109

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