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Cylindromatosis (CYLD) protein, which is a de-ubiquitinase that acts
as a negative regulator of NF-κB signaling, plays a prominent role
in IBD.
1
This manuscript also provided good evidence that genetic
polymorphisms in CYLD are signifcantly associated with human
CD.
1
Moreover, the authors showed that pathogenic bacteria (E. Coli
strain LF82) decrease the expression of CYLD, thereby resulting
in enhanced NF-kB activation in intestinal epithelial cells.
1
This
transcription factor has frequently been cited as a central mediator
of infammation in IBD.
2
Other manuscripts published over the last
10years have also implicated various components of the UPS as being
important in the pathogenesis of IBD.
CYLD
In 2006, Zhang, et al.
3
(working at the NIH) showed that CYLD
defcient mice were more susceptible to colonic infammation, as well
as developing colitis associated cancer.
3
Subsequent studies by Reilly
and co-investigators (including myself) at the Penn State College of
Medicine confrmed these murine colitis fndings.
4
Moreover, we
showed that adoptive transfer of CYLD-/- T cells induced colonic
infammation and symptoms of colitis in recipient mice.
4
Immuno proteasome subunits (LMP2, LMP7, LMP10)
It is now established that when cells are exposed to pro-
infammatory cytokines (IFN-γ, IL-1β, TNF-α), which are up-
regulated during the course of IBD, there is a replacement of
constitutive catalytic proteasome subunits with immuno proteasome
subunits.
5,6
Results from my laboratory, as well as other investigators,
suggest that these immuno proteasome subunits [low molecular mass
polypeptide (LMP) 2 (b1i), multi-catalytic endopeptidase complex-
like-1 (b2i), and LMP7 (b5i)] are involved in the pathogenesis of
experimental colitis and IBD.
5‒7
Novel pharmacological treatments targeting the UPS
A review of the references cited in this editorial implies that
modulation of the UPS, particularly by developing drugs that
selectively target the immuno proteasome would be a worthwhile
endeavor.
1‒7
In this regard, targeting the LMP7 subunit with a
selective small molecule inhibitor (PR-957, ONX-0914) was shown
to be effective in a mouse model of UC.
7
To date, the relevant
literature seems to suggest that targeting the LMP7 or LMP2 immuno
proteasome subunits may be most benefcial for the treatment of
IBD.
5‒7
Of note, two recent review papers (published in 2015) provide
recent insights, which may further aid in the development of safe and
effective drugs that inhibit immuno proteasome activity. Such drugs
could be used not only for treating IBD, but also for the treatment of
other autoimmune diseases (e.g., Rheumatoid Arthritis).
8,9
Therefore,
the transition of immuno proteasome-selective inhibitors into clinical
trials for chronic infammatory diseases seems to be highly warranted
in 2016.
9
Acknowledgements
None.
Confict of interest
Author declares that there is no confict of interest.
References
1. Cleynen I, Vazielle E, Artieda M, et al. Genetic and microbial factors
modulating the ubiquitin proteasome system in infammatory bowel
disease. Gut. 2014;63(8):1265‒1274.
2. Fitzpatrick LR. Novel Pharmacological Approaches for Infammatory
Bowel Disease: Targeting Key Intracellular Pathways and the IL-23/IL-
17 Axis. Int J Infam. 2012:389404.
3. Zhang J, Stirling B, Temmerman ST, et al. Impaired regulation of NF-
kappaB and increased susceptibility to colitis-associated tumorigenesis
in CYLD-defcient mice. J Clin Invest. 2006;116(11):3042‒3049.
4. Reiley WW, Wei J, Lee AJ, et al. Deubiquitinating enzyme CYLD
negatively regulates the ubiquitin-dependent kinase Tak1 and prevents
abnormal T cell responses. J Exp Med. 2007;204(6):1475‒85.
Pharm Pharmacol Int J. 2016;4(1):308‒309. 308
© 2016 Fitzpatrick. This is an open access article distributed under the terms of the Creative Commons Attribution License, which
permits unrestricted use, distribution, and build upon your work non-commercially.
Evidence that the ubiquitin proteasome system plays
a prominent role in infammatory bowel disease:
possible pharmacological approaches
Volume 4 Issue 1 - 2016
Leo R Fitzpatrick
Department of Pharmaceutical & Biomedical Sciences, California
North state University College of Pharmacy, USA
Correspondence: Leo R Fitzpatrick, Assistant Dean
of Research Affairs, Associate Professor, Department of
Pharmaceutical & Biomedical Sciences, California North state
University, College of Pharmacy, 9700 West Taron Drive, Elk
Grove, CA 95757, USA, Tel 9166868364,
Email lftzpatrick@cnsu.edu
Received: January 21, 2016 | Published: February 02, 2016
Pharmacy & Pharmacology International Journal
Editorial
Open Access
Keywords: ubiquitin, proteasome, epithelial, colonic, endopepti-
dase, genetic, cylindromatosis, pharmacological
Abbreviations: IBD, infammatory bowel disease; CD, crohn’s
disease; UC, ulcerative colitis; CYLD, cylindromatosis
Editorial
Infammatory Bowel Disease (IBD), which exists predominantly
as Crohn’s Disease (CD) and Ulcerative Colitis (UC) involves genetic
and microbial factors, which result in chronic infammation of the GI
Tract.
1
A recent manuscript by Cleynen and colleagues showed that the
ubiquitin proteasome system (UPS), which is present in mammalian
cells (e.g., intestinal epithelial cells) relevant to Infammatory Bowel
Disease (IBD), is an important contributor to the pathogenesis of
intestinal infammation.
1
Specifcally, these authors proposed that