IMPACTS  OF  FOOD  ON    INTESTINAL  FUNCTION  &  HEALTH  

JULIE  DALZIEL,  SENIOR  RESEARCH  SCIENTIST,  FOOD  NUTRITION  GENOMICS  AGRI-­‐FOODS  &  HEALTH  

TOKYO,  12  OCTOBER  2010  

AGRESEARCH  

  NZ’s largest Crown Research Institute •  Wholly government-owned •  860 full-time equivalent staff (250 PhDs)

  Research and development funding •  45% revenue from competitive grants •  55% revenue from commercial contracts •  Total annual revenue (08/09): NZ$ 148m •  Small amount of direct Government funding

  Research and development scope •  From “paddock to the plate” •  Basic and applied research

OUR  FOCUS  

  Raise productivity in the NZ pastoral sector in an environmentally sustainable manner.

  Introduce a range of biotechnologies and other technologies to NZ.

  Export our own biotechnologies and other technologies to the world.

AGRESEARCH  SITES:  

Ruakura  (Hamilton)  

Grasslands  (Palmerston  North)  

Wallaceville  (Wellington)  

Lincoln  (Christchurch)  

Invermay  (Dunedin)  

+  several  farms  around  NZ  

AgResearch  Grasslands  Palmerston  North  

AGRESEARCH  SCIENCE  STRUCTURE  

CEO Tom Richardson

GM – Food & Textiles Warren McNabb

Animal Health Bio-based Products & Textiles

Rumen Nutrition & Microbiology

GM – Applied Biotechnologies Jimmy Suttie

Forage Biotechnology

Animal Improvement

Animal Biosciences 

Bioinformatics, Mathematics & Statistics

Forage Improvement

GM – Agriculture & Environment Peter Benfell

Biocontrol & Biosecurity

Agricultural Systems

Climate, Land & Environment

Agri-Foods & Health

Greenhouse Gas Research Centre

NutriLon  Chemistry  

Microbiology  

Metabolism  

AgResearch’s Systems Biology Platform

Proteomics  Metabolomics  

PlaNorm  

FuncLonal  (Epi)genomics  PlaNorm  

BioinformaLcs  MathemaLcs  Modelling  PlaNorm  

Meat  Science   Food  Safety  

Food Nutrition Genomics Dairy Foods Food Microbiology & Safety Meat Science & Technology

DAIRY  FOODS  -­‐  PROTEIN  PURIFICATION  

  Purification of proteins and milk fractions •  lab-scale (mg to gram quantities) •  pilot-scale (gram to kg)

  Anti-fungal, anti-viral, anti-bacterial e.g. nutraceutical food, crop protection, food preservative

(Smolenski et al., 2007, J Proteome Res 6: 207-15)

  Immune-modulating e.g. nutraceutical food

  Enzymes for flavour development e.g. kokumi

Mold growing on food and crop products

Team Leader •  Dr Nicole Roy

Team composition •  12 scientists •  8 technicians •  11 PhD students

Core capabilities •  Functional genomics •  Microbiology •  Cell/tissue bioassays & electrophysiology •  Animal models

Core areas of research •  Food, host and microbial interactions •  Molecular Nutrition (nutritional genomics, epigenomics, metabolomics) •  Neuromotor function and membrane physiology

FOOD  NUTRITION  GENOMICS  TEAM  

The intestinal tract is a highly complex system – food/microbe/mucosal interface

Human intestinal mucosa •  Largest interface (barrier) between

humans and the environment. •  Critical for the balance between

health and disease. •  Crucial to food utilisation; poor

function linked to diet-related diseases.

>25,000 food components

Foods can affect: •  probiotic bacterial growth •  immune system balance •  intestinal barrier function •  intestinal motility

What is intestinal barrier function? Intestinal barrier separates intestinal lumen from underlying tissue and provides a protective interface between internal and external environment of body.

Physical  barrier  (the  epithelium)  

Chemical  barrier  (mucus  layer)  

Immunological  barrier  (immune  cells  of  the  lamina  propria)  

Microbial  barrier  (commensal  bacteria)  

Hooper LV (2009) Nat Rev Microbiol. 7(5):367-74.

Muscle  layers    (smooth  muscle  gut  wall)  

  Intestinal muscle assay

  Fluorescence-based cellular assay

  Intestinal permeability assay

  Patch-clamping

CELL  &  TISSUE  BIOASSAYS  Techniques to measure changes in cell and tissue function in response to food/pharmaceuticals and therefore predict human health outcomes and detect unwanted gastrointestinal side effects.

INTESTINAL  SMOOTH  MUSCLE  Intestinal contraction is determined by circular and longitudinal muscle layers and affected by neuronal inputs

ORAL

NEUROMOTOR  FUNCTION  

Interneuron Longitudinal

muscle motor neuron

Circular muscle

motor neuron

Interneuron Network of neurons

ANAL

  Measures effects of intestinal contents on smooth muscle contractility

  Provides information on whether intestinal contractility is affected.

INTESTINAL  MUSCLE  ASSAY  

Con

tract

ion

forc

e

Control

Test condition

Control

Time

  Indirectly measure changes in membrane permeability by detecting changes in membrane potential or intracellular calcium.

  Provides general information on whether receptor/ion channel mechanisms are affected

  Permeability measured across the cell membrane (fluoresense, patch-clamp), between cells, or both (TEER).

FLUORESCENCE-BASED CELLULAR ASSAY  

apical

basolateral

Cl K

Na2Cl

K

K

2K

ATP

3Na

Cl K

Na2Cl

K

K

2K

ATP

3Na

  TEER measures changes in tight junction resistance across an epithelial Caco-2 cell monolayer using an ohmmeter

  Example shows a control, a bacterial strain that decreases epithelial resistance (strain 2), and another that increases resistance (strain 1).

  The results indicate improved (increased resistance) or weakened (decreased resistance) epithelial barrier function by bacteria (food ingredients could also be used).

TRANS-EPITHELIAL ELECTRICAL RESISTANCE ASSAY (TEER)  

Control Strain 1 Strain 2

bacteria added

ION  CHANNELS  IN  THE  CELL  MEMBRANE  

cellular excitability

muscle contraction, neuronal firing and neurotransmitter release

intestinal motility

cellular permeability

ion and water absorption/secretion

faecal moisture

faecal consistency (diarrhoea/constipation) - microbial balance - enteric nervous system - immune system

Patch-clamping of cells to directly measure ionic currents across cell membranes as ion channels open and close.

ELECTROPHYSIOLOGY  

Express protein Identify cell Record current

Patch-clamp data example of an inhibitory effect measured for a K+ ion channel

ELECTROPHYSIOLOGY  

Dose response relationship

control test condition recovery

Provides specific information on how receptor/ion channel mechanisms are affected.

Dalziel et al. 2005, Toxicology Letters 155: 421-6.

RELEVANT  PUBLICATIONS  

COLLABORATORS  NZ: Auckland University, Liggins (Auckland), Plant & Food Research, Otago

University (Dunedin), Massey University Riddet Institute (Palmerston North).

International:

A/Prof Andrea Meredith, University of Maryland – K+ channel knockout mice

Prof Shunyi Zhu, Chinese Academy of Sciences – K+ channel inhibitors

Dr Yue-kun Ju, University of Sydney – Cardiac ion channels

Prof Richard Aldrich, University of Texas – Ion channel research

Prof Kikuji Itoh, Tokyo University – Germ-free rodents.

Prof Jeremy Wells, Wageningen University – Intestinal barrier function.

Prof Ian Rowland, Reading University – Molecular nutrition/cancer.

Prof Jonathan Powell, Cambridge University – Nanoparticles.

COLLABORATIVE  OPPORTUNITIES  

  Protein purification

  Test effects of food ingredients on intestinal function, including motility and effects on receptors and ion channels

  Explore underlying mechanisms of action

AgResearch  Grasslands  

Palmerston  North  

We invite you to visit us in NZ!