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Impaired antibacterial autophagy links granulomatous intestinal inflammation in Niemann–Pick disease type C1 and XIAP deficiency with NOD2 variants in Crohn's disease

Abstract:

Objective Patients with Niemann–Pick disease type C1 (NPC1), a lysosomal lipid storage disorder that causes neurodegeneration and liver damage, can present with IBD, but neither the significance nor the functional mechanism of this association is clear. We studied bacterial handling and antibacterial autophagy in patients with NPC1.

Design We characterised intestinal inflammation in 14 patients with NPC1 who developed IBD. We investigated bacterial handling and cytokine production of NPC1 monocytes or macrophages in vitro and compared NPC1-associated functional defects to those caused by IBD-associated nucleotide-binding oligomerization domain-containing protein 2 (NOD2) variants or mutations in X-linked inhibitor of apoptosis (XIAP).

Results Patients with the lysosomal lipid storage disorder NPC1 have increased susceptibility to early-onset fistulising colitis with granuloma formation, reminiscent of Crohn's disease (CD). Mutations in NPC1 cause impaired autophagy due to defective autophagosome function that abolishes NOD2-mediated bacterial handling in vitro similar to variants in NOD2 or XIAP deficiency. In contrast to genetic NOD2 and XIAP variants, NPC1 mutations do not impair NOD2-receptor-interacting kinase 2 (RIPK2)-XIAP-dependent cytokine production. Pharmacological activation of autophagy can rescue bacterial clearance in macrophages in vitro by increasing the autophagic flux and bypassing defects in NPC1.

Conclusions NPC1 confers increased risk of early-onset severe CD. Our data support the concept that genetic defects at different checkpoints of selective autophagy cause a shared outcome of CD-like immunopathology linking monogenic and polygenic forms of IBD. Muramyl dipeptide-driven cytokine responses and antibacterial autophagy induction are parallel and independent signalling cascades downstream of the NOD2-RIPK2-XIAP complex.

Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1136/gutjnl-2015-310382

Authors

More by this author
Institution:
University of Oxford
Division:
MSD
Department:
NDM
Sub department:
NDM Experimental Medicine
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
NDM
Sub department:
NDM Experimental Medicine
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MSD
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
NDM
Sub department:
Oxford Ludwig Institute
Role:
Author


More from this funder
Funding agency for:
Gyrd-Hansen, M
Uhlig, HH
Grant:
102894/Z/13/Z
More from this funder
Funding agency for:
Gyrd-Hansen, M
Grant:
102894/Z/13/Z
More from this funder
Funding agency for:
Schwerd, T
Grant:
SCHW1730/1-1
More from this funder
Funding agency for:
Gyrd-Hansen, M
Grant:
102894/Z/13/Z
More from this funder
Funder identifier:
https://ror.org/03tx8dq56
Funding agency for:
Pandey, S


Publisher:
BMJ Publishing Group
Journal:
Gut More from this journal
Volume:
66
Issue:
6
Pages:
1060-1073
Publication date:
2016-03-07
Acceptance date:
2016-01-14
DOI:
EISSN:
1468-3288
ISSN:
0017-5749


Language:
English
Pubs id:
pubs:609214
UUID:
uuid:068f032d-262e-46b8-bf81-3e023839b419
Local pid:
pubs:609214
Source identifiers:
609214
Deposit date:
2016-03-26
ARK identifier:

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