The immunobiology of inflammation and stress MCB 5255; Spring 2015.
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Transcript of The immunobiology of inflammation and stress MCB 5255; Spring 2015.
The immunobiology of inflammation and stress
MCB 5255; Spring 2015
Course description
• A participatory course where each student must give an hour presentation that provides the background and then discusses two current papers in the primary scientific literature on a relevant component of the overall topic (e.g. cancer, autoimmunity, inflammation, etc). Each week’s assignment should be read by all student participants. Students are graded on that presentation, on their participation in the discussions that arise from other student presentations, and for the grant proposal that they write to propose a line of investigation related to their specific topic.
Today’s plan
• Talk about inflammation and stress• My lab’s approach to inflammation and stress
responses• Make plans for the next few weeks/go over
syllabus• Identify topic of interest for student
presentations
Inflammation
• A general term that encapsulates several phenomena: local accumulation of fluid, plasma proteins, and leukocytes as a consequence of physical injury, toxicant exposure, infection or a dysregulated immune response
Benefits of inflammation
• Recruitment of effector cells (PMNs, T lymphocytes, etc) to areas where damage has occurred, infections have been initiated, and where wound healing is required
• Release of complement and antibodies to the local tissue environment to eliminate infections
Early events in inflammation include cytokine and chemokine release
Stress• Physiological or biological stress is an
organism's response to a stressor such as an environmental condition or a stimulus. Stress is a body's method of reacting to a challenge. (wiki)
Consequences of stress responsechanges to adaptive immune activityactivation of innate immunityDanger hypothesis
There are many points of interaction between the different ways the body responds to stress
The stress response according to the nervous system
http://www.stress.org/daily-life/Panic vs dread?
A biological response: Heat shock proteins as immune modulators
Consequences of chronic inflammation
• Can be sustained by genetic defects (e.g. CGD), ongoing mechanical damage, persistent infection, exposure to environmental contaminants that cause cell damage, or which inactivate normal wound healing mechanisms
• Result is bystander damage that can enter positive feedback loop (e.g. inflammatory bowel disease)
metallothionein
Stressors initiate homeostatic responses, including stress protein synthesis. How do these mechanisms alter immune function?
Heat shock proteins glucose regulated proteins FKBP cyclophilins
acute phase proteins some cytokines histone 2B ubiquitin glucocorticoids
Stressors* Immune changes
*Stressors include biological, chemical, physical and psychological events
MDPNCSCATGGSCTCAGSCKCKECKCTSCKKSCCSCCPVGCAKCAQGCVCKGASDKCSCCA
Yellow represents thiols in cysteines, blue spheres are Zn and red spheres are Cd
after Robbins et al.
ISRE GRE BLE MRE TRE GC MRE TATA+1
Induction of MT Gene Transcription
IFN
Ca iono-phore
TNF IL-6 IL-1
phorbalester metal
cations
GC
GC-R
DAG
PKC
cAMP
PKA
[Ca]
Calmodulin-PK
MBPAP2 SP1AP1
-300-800
H2O2
ROS
1000
GRE
inflammatory agents
Structural MT genes in the MT cluster: three exons interrupted by two intronsChromosome 8 (mouse) and Chromosome 16 (human) in syntenic regions
Metallothionein Functions
Intracellular functions:• decreases toxic effects of heavy metals (e.g. Hg, Cd)• acts as a free radical scavenger, regulates cellular redox
potential• serves as a reservoir for essential heavy metals (e.g. Zn, Cu)• regulates NF-kB, Sp-1 transcription factor activity
Extracellular functions:• may redistribute metal cations within body• may bind membrane bound receptors (astrocyte receptor?)
Hypothesis: Metallothionein that is synthesized as a result of stress can alter the capacity of the immune system
Metallothionein-mediated in vivo humoral immunosuppression
22201816141210
20
40
60
80
ovaova/mt
days
mO
D/m
in
Mice were injected with 200 ug OVA with or without the addition of 120 ug MT on day 0 and day 10. Samples obtained on the days indicated were used in ELISA to determine the anti-OVA activity. Results are representative of three independent experiments and are reported as the average of triplicates + s.d.
0
OVA antigen challenges
UC1MT enhances the humoral response to
OVA immunization
0
50
100
150
200
250
300
0 14 18 21 25 32 35 43
Time (days)
an
ti O
VA
resp
on
se (
avera
ge m
OD
/min
)OVA OVA w/ UC1MTOVA w/ Ig Control
BALB/cByJ mice were challenged with 200 ug OVA in the presence or absence of UC1MT or isotype control on day 0 and day 10.
Targeted disruption of metallothionein enhances the
humoral response
0
20
40
60
80
100
120
140
160
180
Day 0 Day 11 Day 13 Day 15 Day 17 Day 19 Day 25 Day 27
Time (days)
avera
ge m
OD
/min
129 WT129 KO
Is there a role for MT in
experimental colitis?
4% DSS H2O
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Dextran sulphate sodium-induced colitis - ACUTE
4% DSS H2O
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 ….
Dextran sulphate sodium-induced colitis - CHRONIC
4% DSSx3
MT knockout and wild type mice in DSS-colitis
MT knockout mice are favored during DSS-colitis
ACUTE COLITIS
MT knockout mice show reduced leukocyte infiltration
P=0.06
Metallothionein and Chemotactic
Factor sequence comparison
(amino acid residues enclosed in boxes are identical, shaded amino acids are homologous at 85% by clustal analysis)
Metallothionein gene cluster synteny: human 16 and mouse 8 chromosomes
This movie was made with a 16mm camera in the 1950s by David Rogers at Vanderbilt University. The neutrophil is "chasing” a Staphylococcus aureus bacterium, added to the blood film (the non-motile cells are erythrocytes) http://expmed.bwh.harvard.edu/projects/motility/neutrophil.html .
Neutrophil chemotaxis is governed by very small gradients
8 Well ECIS Chamber
Courtesy of Applied Biophysics Inc.
ECIS/taxis developed and patented in collaboration with David Knecht
ECIS/taxis Side View
Cell Well
LargeE lectrode
TargetE lectrode
ChemoattractantAgarose
To ECISInstrumentation
ECIS/taxis- automated measurement of dictyostelium folate chemotaxis
UC1MT in acute DSS-colitisUC1MT in acute DSS-colitis
What’s next in this research program?
• What are the possible receptors for an MT-mediated chemotactic response?
• What are the signaling mechanims?• Can we make small molecule analogs that interfere with MT
mediated inflammation?• Are there other inflammatory diseases that are equally
treatable with UC1MT• Will this work in humans?• Does the bacterial analog of MT influence an infected
person’s ability to manage infection?
Topics of potential interest related to the Immunobiology of inflammation and stress
1. Mechanisms of danger-signal mediated immune modulation2. MT and type I diabetes3. Bacterial stress response proteins and their influence on the immune
response4. Chemical toxicants and their roles in chronic inflammation5. The link between psychological stressors and susceptibility to immune
changes in the presence of environmental contaminants6. The chemistry of stress: the role of reactive oxygen and nitrogen species in
inflammation and stress, and the management of ROS and RNS in stress7. Molecular indicators of stress as indicators of immune status8. Stress response proteins and their roles as vaccine adjuvants9. The interplay of infection, stress and the immune response10. Stress and autoimmune disease: positive and negative feedback loops