Plant-derived novel anti-diarrhoeal drugs.

Plant-derived novel anti-diarrhoeal drugs.

Dr John P Winpenny

Secretory diarrhoea continues to be a leading cause of morbidity and mortality
worldwide. Enterotoxin-producing bacteria are thought to cause diarrhoea by
stimulating cAMP-mediated chloride secretion. This secretion is mediated by
the cystic fibrosis transmembrane conductance regulator (CFTR) chloride
channel1. The CFTR channel protein is regarded as a potential therapeutic
target for secretory diarrhoea, as inhibition of the CFTR chloride channel
could prevent secretory fluid loss.

We have access to a number of bacterial multidrug resistance (MDR)
inhibitors, both plant-derived and artificially synthesised, as part of a
collaboration with Professor Simon Gibbons (London School of Pharmacy)2.
As the CFTR chloride channel belongs to the MDR protein family, we
hypothesis that these MDR inhibitors should inhibit the CFTR chloride
channel. This may lead to identification of potential new drug candidates for
the treatment of diarrhoea.

This project will use CaCo-2 cells grown as a polarised, confluent monolayer
on permeable supports (Snapwells). Confluence of monolayers will be
followed by measuring the transepithelial resistance of the cultures. Once
confluent, permeable supports will be incorporated into an Ussing chamber
set-up (Physiologic Instruments). CFTR chloride currents will be activated by
addition of forskolin to the basolateral side of the bath and the effect of the
MDR inhibitor compounds on the CFTR-stimulated short circuit current (Isc)
will be assessed.

References

1. Field, M. (2003). Intestinal ion transport and the pathophysiology of
diarrhea. Journal of Clinical Investigation 111, 931-943.
2. Stavri, M, Piddock, LJV, Gibbons, S. (2007). Bacterial efflux pump inhibitors
from natural sources. Journal of Antimicrobial Chemotherapy 59, 1247-1260.

Factors predisposing to fluid intake in elderly residents of
care homes.

Dr. Lee Hooper

Dehydration in older people is associated with high levels of risk of adverse
health outcomes and death, and contributes to many major causes of death
and morbidity, including falls, fractures, heart disease, confusion, delirium,
heat stress, constipation, renal failure, pressure ulcers, poor wound healing,
poor rehabilitation outcomes, infections, seizures, drug toxicity, and poor
quality of life (1). Prevention of dehydration, or promotion of fluid intake, in
the community, especially in care homes where the risk is high, would be
good for older people and reduce NHS costs (2).

This study will work to identify cues and factors that encourage drinking in
care home residents in Norfolk using qualitative and quantitative methods (3).

References

(1) Warren JL, Edward Bacon W, Harris T, McBean AM, Foley DJ, Phillips C. The
burden and outcomes associated with dehydration among US elderly, 1991.
American Journal of Public Health 1994;84:1265-9.
(2) Jointly produced by the Department of Health and the Nutrition Summit
stakeholder group. Improving Nutritional Care: A joint Action Plan. www dh gov
uk/publications 2007 [cited 2009 Dec 17];
(3) Mentes JC. Oral hydration in older adults. American Journal of Nursing
2006;106(6):40-9.

Health effects of omega-3 fats: a systematic review and
meta-analysis

Dr. Lee Hooper

Omega-3 fats are found in oily fish and some plant-based oils. It is thought
that high levels of omega-3 intake predisposed humans in pre-history to grow
larger brains, becoming the species we know today. Reduced levels of
omega-3 fats in the modern diet may be responsible for a variety of health
effects including cardiovascular disease, auto-immune and allergic type
illnesses and a variety of other ills.

This project will explore the effects of omega-3 fats on a wide range of health
outcomes. The methodology will be a systematic review (or overview) of
systematic reviews on the health effects of omega-3 fats. This is an
opportunity for a student to develop skills in systematic review and meta-
analysis, and to produce a high quality publication.

References
Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and
cancer: systematic review. (2006). Hooper L, Thompson RL, Harrison RA,
Summerbell CD, Ness AR, Moore HJ, Worthington HV, Durrington PN,
Higgins JP, Capps NE, Riemersma RA, Ebrahim SB, Davey Smith G. BMJ.
2006 332(7544):752-60.

Prostanoid receptor expression and function in Barrett’s
oesophagus and oesophageal adenocarcinoma

Dr Ian Beales

Oesophageal adenoncarcinoma is a serious clinical problem in the UK.
Further understanding of the pathogenesis is important to design more
effective treatment and preventative strategies. We have recently shown that
prostaglandins have central roles in the stimulation of proliferation and
inhibition of apoptosis in the development of this cancer. However the
receptors involved and mechanism underlying these effects are unknown. It is
also unknown whether thromboxanes, alternative end-products of arachidonic
acid metabolism affect the oncogenic behaviour of oesophageal
adenocarinioma cells.
The project will examine the expression of the different EP- and TX- receptors
in cultured cells and tissue blocks and use selective agonists and antagonists
to examine the functional role of the different receptors. Further detail studies
examining the downstream intracellular signalling will then be undertaken.
The project will involve a cell culture techniques, immunohistochemistry,
receptor function analysis and image analysis.

References
1. Leptin stimulates proliferation and inhibits apoptosis in Barrett’s esophageal
adenocarcinoma cells by COX-2 dependent, PGE-2 mediated transactivation
of the EGF receptor and JNK activation. Ogunwobi O, Mutungi G and Beales
ILP. Endocrinology (2006) 147, 4505-4516
2. Leptin synergistically enhances the anti-apoptotic and growth-promoting
effects of acid in OE33 oesophageal adenocarcinoma cells in culture.
Beales ILP & Ogunwobi OO (2007)
Mol Cell Endocrinol (2007) 274, 60-68
.3. Microsomal prostaglandin synthase-1 inhibitiion blocks proliferation and
enhances apoptosis in oesophageal adenocarcinoma cells without affecting
endothelial prostacyclin production.
Beales ILP and Ogunwobi OO
Int J Cancer (2010) 126, 2247-55

The role of cyclo-oxygenase inhibitors in the aetiology of
inflammatory bowel diseases

Dr Ian Beales

The case of inflammatory bowel disease (Crohn’s disease and ulcerative
colitis) remains unclear. Equally the specific factors which trigger acute
exacerbations of these diseases are not fully understood. There are published
data suggesting that cyclo-oxygenase inhibitors (NSAIDS, paracetomol and
coxibs) can be harmful in inflammatory bowel disease, however there are
conflicting data suggesting that these drugs have minimal effects or may even
be beneficial.
The project will involve a case-control study of cyclo-oxygenase inhibitor use
in patients presenting with de novo IBD and also those with flare-ups of
previously quiescent IBD and compare the exposure to these drugs with
control groups with stable IBD in remission and non-IBD controls. The project
will involve questionnaire design, recruitment of subjects, data collection and
analysis.

References (up to 3)
1. Meyer et al. Relapse of Inflammatory bowel disease associated with use of
nonsteroidal anti-inflammatory drugs. Dig Dis Sci (2006): 51: 168-172
2. Feagins and Cryer. Do non-steroidal anti-inflammatory drugs cause
exacerbations of inflammatory bowel disease? Dig Dis Sci (2010): 55: 226-
232

Chemoprevention of oesophageal cancer with statins

Dr Ian Beales

The incidence of oesophageal adenocarcinoma is increasing rapidly in the
UK. The two main risk factors are obesity and gastro-oesophageal reflux
disease and the overall prognosis remains poor despite multi-modality
therapies. Preventative therapies may improve the outlook. We have recently
shown that statins (HMG-CoA reductase inhibitors) reduce proliferation and
inhibit apoptosis in oesophageal cancer cells. It is not yet known if these
drugs have any beneficial effects on clinical outcomes.
The project will involve a case-control study of statin use in patients with
oesophageal adenoncarcinoma, oesophageal squamous cancer and gastric
cardia cancer compared with non-cancer controls to determine the odds ratio
of cancer in those with a past history of statin use.
The project will involve questionnaire design, recruitment of subjects, data
collection and analysis.

References (up to 3)
1. Ogunwobi and Beales. Statins inhibit proliferation and induce apoptosis in
Barrett's esophageal adenocarcinoma cells. Am J Gastroenterol
2008;103(4):825-37

2. Hawk ET, Viner JL Statins in esophageal cell lines: promising lead? Am J
Gastroenterol. 2008:103(4):838-41.

Lower Oesophageal sphincter-relaxing drugs and
oesophageal cancer

Dr Ian Beales

Oesophageal adenoncarcinoma is becoming and increasing clinical problem
in the UK. Some data have been published suggesting that drugs which relax
the lower oesophageal sphincter may increase the risk of oesophageal
cancer, however the data that are available are conflicting and have not
always separated out the different types of oesophageal and gastric cancers
or different drugs. We have recently performed a systematic review and this
suggested that whilst anti-cholinergics alone increased the risk of oesopheal
cancer, nitrates could actually reduce the risk of gastric cardia cancer. This
suggests that the different sphincter relaxing drugs may differentially modulate
the risk of cancer.
The project will involve a case-control study of drugs use in statin use in
patients with oesophageal adenoncarcinoma, oesophageal squamous cancer
and gastric cardia cancer compared with non-cancer controls to determine the
odds ratio of cancer in those with exposure to different vaso-dilator drugs.
The project will involve questionnaire design, recruitment of subjects, data
collection and analysis.

References
1. Lagergren at al. Association between medications that relax the lower
oesophageal sphincter and the risk for esophageal adenocarcinoma. Ann Int
Med 2000: 133; 165-175

2. Vaughan et al. Risk of esophageal and gastric adenocarcinomas in relation
to use of calcium channel blockers, asthma drugs and other medications that
promote gastroesophageal reflux. Cancer Epidemiology, Biomarkers and
Prevention 1998: 7; 749-756.

A Prospective Study of the Natural History of Sinusitis

Mr. Carl Philpott MB ChB, FRCS (ORL-HNS) DLO, MD, PGCME

Chronic rhinosinusitis (CRS) represents a significant chronic disease burden
on the NHS; in the USA it affects an estimated 31 million Americans per year
(10% of the population)1. Due to the common nature of this problem 2, it has
an impact upon the productivity of the workforce as it is predominantly a
disease that affects patients aged 40-60 years old. In fact “sinusitis” was cited
as one of the top-10 most costly physical health conditions to American
businesses 5. This project involves a prospective population study of age- and
sex-matched controlled atopic and non-atopic individuals to will enable
characterization of the incidence of all upper respiratory tract symptoms
including acute and chronic rhinosinusitis over a 5-year period. To achieve
this, a prospective pilot study of 100 patients who present with symptoms of
acute or chronic rhinosinusitis to their GP for the first time would be
conducted. A control group of 100 subjects would also be recruited using age
and sex matched subjects derived from the same GP practices.

References

1. Slavin RG. Management of sinusitis. J Am Geriatr Soc. 1991
Feb;39(2):212-7.
2. Durr DG, Desrosiers MY, Dassa C. Impact of rhinosinusitis in health care
delivery: the Quebec experience. J Otolaryngol. 2001;30(2):93-7.
3. Goetzel RZ, Hawkins K, Ozminkowski RJ, Wang S. The health and
productivity cost burden of the "top 10" physical and mental health conditions
affecting six large U.S. employers in 1999. J Occup Environ Med. 2003
Jan;45(1):5-14.

Cellular and immunological studies of Crohn’s Disease.

Prof T. Wileman and Prof. S. Carding

Recent genome-wide screens show that susceptibility to Crohn’s
inflammatory bowel disease is linked to a mutation in autophagy gene
ATG16L . Autophagy is a pathway of intracellular degradation that plays a
central role in the disposal of unwanted materials such as damaged
organelles and infectious microorganisms. Autophagy can also influence
immune responses by delivering microorganisms to antigen presentation
pathways. The current hypothesis is that Atg16 mutations seen in Crohn’s
disease alter the barrier function of gut epithelial cells resulting in changes in
processing and presentation of microbial antigens or defects in secretion of
defensins from Paneth cells, leading to gut inflammation. We are engineering
ATG16L mutations into mice to generate a mouse model of Crohn’s disease.
This project will use the mouse model to generate mouse gut epithelial
cultures to study how mutations in ATG16L affect autophagy in gut epithelial
cells, and how these changes impact on innate defences against infection and
inflammation.

References

1. Autophagy: in sickness and in health. Cuervo A. M. Trends Cell Biol. 2004,
14: 70-77
2. Autophagy and antiviral immunity. Lee HK and Iwasaki A 2008: Current
Opinion in Immunology 20: 23-29
3. Intestinal epithelial cell regulation of mucosal inflammation 2004. Yu Y,
Sitaraman S, Gewirtz AT. Immunol. Res. 2004;29:55-68.

Innate response to pathogen infection in the gut

Penny Powell and Kevin Tyler

The first response of cells to microbial infection is to evoke immediate innate
responses. Pathogen-associated molecular patterns such as double
stranded RNA are recognized by pattern recognition receptors which include
toll-like receptors, the Rig-like helicases (RLH) Rig-I and mda 5, and the
nucleotide-binding domain receptors (NLRs). These pathways lead to the
induction of interferon and cytokines. They also have direct links with
autophagy that can lead to the destruction of pathogens in lysosomes.

In this project the student will focus on mouse gut epithelial cell cultures and
characterize the activation of the interferon and autophagy pathways in
response to gut pathogens and pathogen components. In particular, the
experiments will develop GFP-reporter and live cell imaging technologies to
study innate responses to pathogen infection at the single cell level.
Understanding the links between these pathways and the innate early
responses of gut epithelial cells would have implications for aetiology and
pathogenesis of a number of gut diseases which arise from infection and
inflammation.

References

1. Cytoplasmic nucleic acid sensors in antiviral immunity. Ranjan P, Bowzard
JB, Schwerzmann JW, Jeisy-Scott V, Fujita T, Sambhara S. Trends Mol
Med. 2009 :15(8):359-68. Review.
2. Autophagy and antiviral immunity. Lee HK and Iwasaki A 2008: Current
Opinion in Immunology 20: 23-29
3. Cryptosporidium parvum infection rapidly induces a protective innate
immune response involving type I interferon. Barakat FM et al., 2009. J.
Infect. Dis. 200:1548-55.

Microbe-host interactions in the gut: The influence of host
immune system on the development and function of the gut

microbiota

Prof. SR Carding

The human body can be considered as a super-organism composed of an amalgam of
both microbial and human cells, depending on each other for survival. This is
particularly apparent in the gastrointestinal tract where the resident microbiota is the
key component of the human digestive ecosystem and is pivotal for the induction and
maintenance of (oral) tolerance and a peaceful coexistence with the host. Despite the
central importance of this relationship in health and disease, how it is established and
how the host “learns” to tolerate the constant barrage of food-derived antigens and the
presence of a complex community of microbes while retaining the ability to mount
effective responses to repel pathogens is one of the major unresolved questions in
biology.

This project proposes that establishment of host (oral) tolerance to the intestinal
microbiota is genetically regulated involving local T cell-mediated selection of
compatible microbial species. We will test this by studying microbial poulations in
the gut of genetically modified strains of mice with specific deficiencies in T-cells.
High throughput ‘omics technologies will be used to define how differences in T-cell
populations influence the development and function of the GI-tract microbiota.

Baumgart DC, Carding SR. (2007) Inflammatory bowel disease: cause and
immunobiology. Lancet. 369(9573):1627-40.

Pathogenicity Determinants of Giardia

Kevin Tyler and Paul Hunter

Giardiasis is one of the most prevalent gastrointestinal infections worldwide
and is associated with profound diarrhoea and enormous child mortality.
Giardia is a single celled parasite with eight flagella and an adhesive disk
which are involved in adhesion of intestinal epithelia enabling them to resist
the peristaltic pressure and to persist and proliferate extracellularly within the
gut. Different strains of giardia vary greatly in virulence and many individuals
can carry giardia asymptomatically. Recent completion of the genomes of
three Giardia assemblages, two virulent and one avirulent indicate that the
share >95% of their approximately 5000 genes. This provides a timely
opportunity for identification of proteins that may determine virulence.
Our preliminary studies indicate that virulence may be determined by
proteases secreted by the parasite. This project will use the genome
assemblies to identify proteases that differ between strains of different
virulence and then study their expression and substrate specificity. It is hoped
that it will be possible to identify non-toxic competitive protease inhibitors for
use as medicines or foodstuffs may represent a straightforward way to
alleviate or cure disease.

References

1)Hunter PR, Thompson RC.(2005) Int J Parasitol. 35:1181-90.
The zoonotic transmission of Giardia and Cryptosporidium.

2)Bouzid M, Steverding D, Tyler KM. 2008Detection and surveillance of
waterborne protozoan parasites. Curr Opin Biotechnol. 19(3):302-6.