Alternatively Spliced Forms of Tollip Regulate Inflammatory Signalling in Macrophages
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Author(s)
Primary Supervisor
Wells, Christine
Other Supervisors
Loughlin, Wendy
Cobbold, Christian
Year published
2012
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Show full item recordAbstract
Alternative splicing is one of the mechanisms which drives diversification of innate immune responses. Spliced isoforms of Toll-interacting protein (Tollip), a negative regulator of TLR2-, TLR4- and IL-1R-induced signalling, have been identified to express at endogenous level in human and mouse macrophages. In the current study, we focused on two Tollip isoforms, the full-length Tollip.a and a mouse-specific isoform Tollip.b that lacks the ubiquitin-binding CUE domain. We asked for the effects and consequences of alternative splicing of Tollip in innate immune responses. We wanted to know if alternative splicing of this ...
View more >Alternative splicing is one of the mechanisms which drives diversification of innate immune responses. Spliced isoforms of Toll-interacting protein (Tollip), a negative regulator of TLR2-, TLR4- and IL-1R-induced signalling, have been identified to express at endogenous level in human and mouse macrophages. In the current study, we focused on two Tollip isoforms, the full-length Tollip.a and a mouse-specific isoform Tollip.b that lacks the ubiquitin-binding CUE domain. We asked for the effects and consequences of alternative splicing of Tollip in innate immune responses. We wanted to know if alternative splicing of this negative regulator has causative effect in the diversification of immune signalling and if each isoform plays a role in resolving inflammatory responses. We have developed a mouse cell model to study the function of these Tollip isoforms by over-expressing or knocking-down the variants in a macrophage-like cell line, RAW264.7. Our studies showed that endogenous Tollip.b was expressed at a very low level, whereas Tollip.a was expressed abundantly in macrophages. Over-expressing either of the Tollip isoforms caused dramatic changes in cell morphology and cell proliferation. Further investigation into LPS-responsive signalling in these recombinant cell lines revealed an altered capacity to signal through MAPK pathways, resulting in altered cytokine production.
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View more >Alternative splicing is one of the mechanisms which drives diversification of innate immune responses. Spliced isoforms of Toll-interacting protein (Tollip), a negative regulator of TLR2-, TLR4- and IL-1R-induced signalling, have been identified to express at endogenous level in human and mouse macrophages. In the current study, we focused on two Tollip isoforms, the full-length Tollip.a and a mouse-specific isoform Tollip.b that lacks the ubiquitin-binding CUE domain. We asked for the effects and consequences of alternative splicing of Tollip in innate immune responses. We wanted to know if alternative splicing of this negative regulator has causative effect in the diversification of immune signalling and if each isoform plays a role in resolving inflammatory responses. We have developed a mouse cell model to study the function of these Tollip isoforms by over-expressing or knocking-down the variants in a macrophage-like cell line, RAW264.7. Our studies showed that endogenous Tollip.b was expressed at a very low level, whereas Tollip.a was expressed abundantly in macrophages. Over-expressing either of the Tollip isoforms caused dramatic changes in cell morphology and cell proliferation. Further investigation into LPS-responsive signalling in these recombinant cell lines revealed an altered capacity to signal through MAPK pathways, resulting in altered cytokine production.
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Thesis Type
Thesis (PhD Doctorate)
Degree Program
Doctor of Philosophy (PhD)
School
School of Biomolecular and Physical Sciences
Copyright Statement
The author owns the copyright in this thesis, unless stated otherwise.
Item Access Status
Public
Subject
Toll-interacting protein
Tollip isoforms
innate immune responses
Tollip.b
Tollip.a