Transcript Mutant Protein Tyrosine Phosphatase N2 (PTPN2)Increases

Disclosures
 Nothing to disclose
Gastrointestinal Barrier
 Aids in the absorption of
nutrients while excluding
harmful molecules and
bacteria.
 Defective epithelial barrier is
a hallmark of UC and CD.
 Barrier dysfunction is in part
driven by IFNg signaling.
 Genome-Wide Association
Studies show that SNP in
Protein Tyrosine
Phosphatase N2 is
Associated with increase
incidence of CD and UC.
Abreu, Reviews Immunology 10, 131-144 (February 2010)
PTPN2 Restricts IFNg-Mediated
Barrier Dysfunction
PTPN2 is a negative regular of IFNg
signaling.
PTPN2 protects epithelial barrier
function.
Loss of PTPN2 causes:
• Increased epithelial permeability
• Decreased epithelial resistance
Scharl, M et al., Gastroenerology, 2009
McCole, DF, NY Academy of Science, 2012
Tight-Junction
Turner JR. Nat Rev Immunol
2009;9:799-809.
Ivanov AI. Am J Pathol.
2010 Aug;177(2):512-24
PTPN2 KO Mice Show Increased
Permeability in Proximal Colon
 Mount tissue in Ussing Chamber
humanbiology.wzw.tum.de
 Applied FD4 to the mucosal side
 Sampled at the serosal side (2 hours).
Mislocalization of Occludin & ZO-1 from
tight junctions in PTPN2 KO mouse colon
Arrows indicate location of tight
junctions.
Knock-out exhibits
internalization and
mislocalization of occludin.
C216S Mutant Cell line
HCA7 intestinal epithelial cell line
216 Cysteine to Serine (C216S)
Lentiviral Vector
Doxycycline activation
Detection of HA Tag in C216STransduced Cells
HA-TC45 expression confirmed in DOX induced condition
Nearly 3-fold increase in PTPN2 with increased transactivator
protein
C216S expressing cells show
increased phospho-STAT1
ZO-1 and Occludin are reduced
in C216S mutant cell line
PTPN2 mutant cells show reduced
occludin/ZO-1 co-localization
*
Conclusion
 PTPN2 KO mice show increased colonic FITCdextran permeability.
 Occludin appears mislocalized from the tight junctions
in PTPN2 KO.
 C216S mutant cells have altered tight junction
composition.
 Therefore, loss of PTPN2 expression or activity in vivo
and in vitro compromises barrier function possibly
through occludin mislocalization.
Acknowledgements
 Michel Tremblay – McGill University
 Tony Tiganis – Monash University