Oxidative stress, danger, and immune diseases Intro slides Spring 2013 MCB 5255
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- Slide 1
- Oxidative stress, danger, and immune diseases Intro slides
Spring 2013 MCB 5255
- Slide 2
- Reactive Oxygen Species Molecules or ions formed by the
incomplete one-electron reduction of oxygen Include singlet oxygen;
superoxides; peroxides; hydroxyl radical; and hypochlorous acid
Contribute to the microbicidal activity of phagocytes, regulation
of signal transduction and gene expression, and the oxidative
damage to nucleic acids; proteins; and lipids
- Slide 3
- Formation and Function In immune function, synthesized by
dedicated enzymes in phagocytic cells Generated for killing
engulfed bacteria Unavoidable byproduct of cellular respiration
Interaction of ionizing radiation with biological molecules
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- Oxidative Stress SIGMA-ALDRICH
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- Oxidative Stress Oxidative stress is imposed on cells as a
result of one of three factors: 1) an increase in oxidant
generation, 2) a decrease in antioxidant protection, or 3) a
failure to repair oxidative damage. Cell damage is induced by
reactive oxygen species (ROS). ROS are either free radicals,
reactive anions containing oxygen atoms, or molecules containing
oxygen atoms that can either produce free radicals or are
chemically activated by them. Examples are hydroxyl radical,
superoxide, hydrogen peroxide, and peroxynitrite. The main source
of ROS in vivo is aerobic respiration, although ROS are also
produced by peroxisomal -oxidation of fatty acids, microsomal
cytochrome P450 metabolism of xenobiotic compounds, stimulation of
phagocytosis by pathogens or lipopolysaccharides, arginine
metabolism, and tissue specific enzymes. Under normal conditions,
ROS are cleared from the cell by the action of superoxide dismutase
(SOD), catalase, or glutathione (GSH) peroxidase. The main damage
to cells results from the ROS-induced alteration of macromolecules
such as polyunsaturated fatty acids in membrane lipids, essential
proteins, and DNA. Additionally, oxidative stress and ROS have been
implicated in disease states, such as Alzheimers disease,
Parkinsons disease, cancer, and aging. References Fiers, W., et
al., More than one way to die: apoptosis, necrosis and reactive
oxygen damage Oncogene., 18, 7719-7730 (1999). Nicholls, D.G., and
Budd, S.L., Mitochondria and neuronal survival. Physiol. Rev., 80,
315- 360 (2000). Hayes, J.D., et al., Glutathione and
glutathione-dependent enzymes represent a co- ordinately regulated
defense against oxidative stress. Free Radic. Res., 31, 273-300
(1999).
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- Free Radical Production
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- Oxidative Stress An imbalance between the production and
manifestation of reactive species and the ability to readily
detoxify the reactive intermediates Can cause damage to all
components of the cell including proteins, lipids, and DNA ROS vs
RNS Highly reactive molecules containing oxygen Peroxides, hydroxyl
radicals, superoxide Highly reactive molecules containing nitrogen
Nitrogen dioxide (NO2) and dinitrogen trioxide (N2O3)
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- Antioxidant A molecule capable of inhibiting the oxidation of
other molecules Oxidation: Loss of electron(s) resulting in an
increase in oxidation state Reduction: Gain of electron(s)
resulting in a decrease in oxidation state Antioxidants are
reducing agents Prevent reactive species from causing damage in the
body Both endogenous and exogenous antioxidants Endogenous: SOD,
glutathione peroxidase, CAT Exogenous: vitamin C, vitamin E,
carotenoids and polyphenols
- Slide 10
- Defenses against ROS Antioxidant enzymes such as Superoxide
Dismutase and Catalase (2H 2 O 2 -> 2H 2 O + O 2 ) Antioxidants
such as glutathione GSH Glu-cys-gly tripeptide Antioxidant proteins
such as Metallothionein
- Slide 11
- Autoimmunity: self recognition by the immune response Dual
recognition (self-MHC plus antigenic peptide) Jerne network
hypothesis dont eat me signaling (CD47 on erythrocytes) Autoimmune
disease: self recognition with damaging consequences to tissue
function Tissue specific (e.g. T1D) Systemic (SLE) Danger signals
Autoimmunity vs Autoimmune disease
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- 4 main hypersensitivities (I-IV) Type I Anaphalaxis; Immediate;
IgE mediated mast cell degranulation Allergies, atopy Type II
Cytotoxic (IgM and IgG mediated) Erythroblastosis fetalis,
autoimmune hemolytic anemia, pemphigus vulgaris Type III Immune
complex Serum sickness, RA, Type IV DTH/contact sensitivity Contact
dermatitis, T1D, RA, Multiple sclerosis Hypersensitivities
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- Figure 10-2
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- Figure 10-1
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- Discrimination of self vs non-self Central tolerance develops
in thymus and bone marrow (negative selection to eliminate cells
reactive with antigens Present soon after cell expresses antigen
receptor Present at high concentration over long periods of time
Peripheral tolerance/anergy When cells encounter antigen in the
absence of co- stimulatory signals that are usually provided by
inflammation Antigen segregation Physical barriers to restrict
immune cell access Thyroid, pancreas, intracellular Regulatory
cells that suppress responses Clonal deletion post activation
Tolerance
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- Organ specific T1D Multiple sclerosis Graves disease Autoimmune
hemolytic anemia Myasthenia gravis Systemic RA Scleroderma SLE
Differentiation of autoimmune diseases; organ specific vs
systemic
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- diseaseautoantibodySymptom Myesthenia gravisAnti-acetylcholine
receptorMuscle weakness Graves diseaseAnti-thyroid stimulating
hormone receptor Hyperthyroidism Thrombocytopenic
propuraAnti-platelet antibodiesBruises and hemorrhaging Pemphigus
vulgarisAnti-desmogleinBlistering rash Examples of autoimmune
disease that can be transferred across the placenta
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- DiseaseT cellsB cellsAntibody SLEPathogenic help for antibody
Present antigen to T cells Pathogenic T1DPathogenicPresent antigens
to T cells Present but unclear role Myesthenia gravisHelp for
antibodyAntibody secretionPathogenic Multiple
sclerosisPathogenicPresent antigen to T cells Present but unclear
role Components of immunity that are part of autoimmune
disease
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- Pathogens Cross-reactive antigens/molecular mimicry Lyme
arthritis Rheumatic fever Chronic inflammation, immune
dysregulation Disruption of cell/tissue barriers Sympathetic
ophthalmia (granulomatous uveitis) Toxicants and other stressors
Genetic predisposition Combinations of the above Routes to
Autoimmune Disease
- Slide 20
- http://pubs.acs.org/doi/pdf/10.1021/tx9003787 (see class
website for link)
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- Figure 10-28 part 1 of 2
- Slide 22
- Figure 10-28 part 2 of 2
- Slide 23
- Single gene models Fas, FasL; ALPS (defects in apoptosis,
lymphoaccumulation, angergy and SLE-like autoimmune disease) Mev;
viable motheaten, Hcph-1; SHP1 (chronic inflammation) IPEX immune
dysregulation X linked recessive mutation in transcription factor
FoxP3; severe allergic inflammation, hemolytic anemia,
thrombocytopenia, etc. Deficiency in CD25 (IL2R); impaired
peripheral tolerance CTLA4 mutation; Graves disease, T1D, etc. C1q
mutation SLE MHC associations with autoimmune disease (e.g.
HLA-B27) Genes involved in autoimmune disease
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- Mutations at the Motheaten Locus are Within the Hcph Gene
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- Negative regulator of signal transduction growth factor
receptors: c-kit, EPO activation signaling: BCR, TCR, NK activating
receptor SHP-1 inactivates anti-apoptotic signaling molecules in
neutrophil proliferation induces apoptosis in sympathetic neurons
Function of SHP-1
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- Clinical disease in viable motheaten mice Anemia
Immunodeficiency Autoimmunity Death from acidophilic macrophage
pneumonia
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- Macrophage pneumonia in me v /me v mice me v /me v +/?
- Slide 28
- GWAS genome wide associational studies Family studies to
identify SNP that track with autoimmune disease Animal models with
mutations in candidate genes Meta-analysis of data to enlarge
patient populations studied for autoimmune disease Approaches to
identifying genes involved in autoimmune disease
- Slide 29
- Biochemical events that potentiate autoimmunity events that
cause damage to membrane, etc Reactive oxygen, chronic inflammation
Biochemistry of damaging events associated with autoimmune disease
Reactive oxygen, chronic inflammation Biochemistry of autoimmune
disease
- Slide 30
- Figure 1. Pathogenesis of diabetic microvascular complications.
This schematic proposes that the development of microvascular
complications begins early in the course of diabetes, well before
clinical diabetes is detected. Certain genetic characteristics or
polymorphisms (Apo E4, Aldose reductase, ACE) may increase
individual predisposition for development of microvascular
complications of diabetes [30,31], whereas other genetic factors,
such as the toll receptor, are protective and decrease
predisposition. The various inflammatory mediators listed under the
heading of inflammation cause direct cellular injury and initiate
the cycle of functional and progressive pathologic changes, which
ultimately manifest as microvascular complications [13,1518,21]. As
the disease progresses, lipotoxicity [28], glucotoxicity [42,43],
and epigenetic factors further contribute to the functional and
pathologic changes. Intervention with insulin or insulin
sensitizers, particularly in the early stages of pathogenesis, can
counteract inflammatory changes, control glycemia, prevent
formation of advanced glycation end products, and ameliorate
oxidative-stress-induced overactivation of poly adenosine
diphosphate ribose polymerase (PARP), with the potential to change
the natural history of microvascular complications [29,37]. ApoE4 =
Apolipoprotein E4; ACE = Angiotensin-converting enzyme; PKC =
Protein kinase C beta; IL-6 = Interleukin-6; TNF = Tumor necrosis
factor alpha; NF B = Nuclear factor kappa B. Adapted with
permission from Vinik A, Mehrbyan A. Diabetic neuropathies. Med
Clin North Am 2004; 88: 947999
http://onlinelibrary.wiley.com/doi/10.1002/dmrr.530/pdf Diabetes
Metab Res Rev 2005; 21: 8590.
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-
http://nihroadmap.nih.gov/epigenomics/epigeneticmechanisms.asp
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- Histone modifications
http://www.nature.com/nsmb/journal/v14/n11/images/nsmb1337-F1.gif
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-
http://www.cellsignal.com/reference/pathway/Histone_Methylation.html
- Slide 34
- H3K4me3 demethylases : link between histone modifications and
XLMR. X-linked mental retardation (XLMR) gene SMCX (JARID1C), which
encodes a JmjC-domain protein, reversed H3K4me3 to di- and mono-
but not unmethylated products//Cell 2007 The putative oncogene
GASC1 demethylates tri- and dimethylated lysine 9 on histone
H3//Nature (2006) 442: 307-11. Sustained JNK1 activation is
associated with altered histone H3 methylations in human liver
cancer. //J Hepatol. 2009, 50: 323-33 Perturbation of epigenetic
status by toxicants// Toxicology Toxicology LettersVolume 149,
Issues 1-3, 1 April 2004, Pages 51-58me 149, 1-3, l 2004, Pages
51-58 Diabetes is not the only context in which histone methylation
is potentially important. For example:
- Slide 35
- http://www.cdc.gov/diabetes/consumer/learn.htm Type 1 diabetes,
which was previously called insulin-dependent diabetes mellitus
(IDDM) or juvenile-onset diabetes, may account for 5% to 10% of all
diagnosed cases of diabetes. Type 2 diabetes, which was previously
called non-insulin-dependent diabetes mellitus (NIDDM) or
adult-onset diabetes, may account for about 90% to 95% of all
diagnosed cases of diabetes. Gestational diabetes is a type of
diabetes that only pregnant women get. If not treated, it can cause
problems for mothers and babies. Gestational diabetes develops in
2% to 5% of all pregnancies but usually disappears when a pregnancy
is over. Other specific types of diabetes resulting from specific
genetic syndromes, surgery, drugs, malnutrition, infections, and
other illnesses may account for 1% to 2% of all diagnosed cases of
diabetes.
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- Rate of new cases of type 1 and type 2 diabetes among youth
aged
- Slide 37
- Humanized mouse models Humanized mouse models to study human
diseases Brehm et al.
- Slide 38
- NOD/SCID/Akita mouse
- Slide 39
- Each presentation is ~1 hour Spend first 20 minutes or so
describing the fundamental information: what do we need to know to
understand the papers you have assigned? How does this presentation
fit into the course main topic? Divide the second 30 minutes into
discussions of each of the two contemporary papers that you
assigned to the class at the previous class period Your
presentations
- Slide 40
- Grantsmanship: NIH Steps to the NIH grant application process
http://funding.niaid.nih.gov/researchfunding/grant/pages/apply
ing.aspxhttp://funding.niaid.nih.gov/researchfunding/grant/pages/
NIH electronic grant forms
http://grants.nih.gov/grants/funding/424/index.htmnih.gov/grantndex
Examples of outstandExamples of outstanding titles and abstacts s
htthttp://funding.niaid.nih.gov/researchfunding/grant/pages/titleabs.aspxfunding.niaid.nih.gov/researchfunding
Search engine for currently funded grants gine for unded gra
http://projectreporter.nih.gov/reporter.cfmp://projectreporter.nih.gov/reporte
Tongue-in-cheek": how to fail in grant writing ln grwriting
http://chronicle.com/article/How-to-Fail-inhttp://chronicle.com/article/How-to-Fail-in-Grant-Writing/125620/
- Slide 41
- What is the fundamental hypothesis that is being tested? What
techniques did they use that we have to understand to evaluate the
data? What are the most important figures/data sets that we should
discuss? Are there alternative interpretations of their data? What
conclusions did they reach? What new questions do they open up with
their results? Discussion points to include
- Slide 42
- Hypothesis and ONE specific aim are due March 5 to be discussed
on March 6 th Grant is due May 5 (first day of exam period) by 5pm
(hard copy plus electronic e-mailed file please) Grant
application
- Slide 43
- TEXT: Hypothesis and specific aim (0.5 page) Background and
Significance (3-4 pages) What do we know about the system? What
makes this hypothesis tenable? How is the approach you propose
innovative? Research designs and Experimental approach (4-5 pages)
Rationale Experimental design and methods Anticipated outcomes
Potential pitfalls and alternative approaches We will talk about
NIH forms later in the semester Grant format:
- Slide 44
- Inflammatory Bowel Disease Include: Crohns Disease Ulcerative
Colitis Autoimmune diseaseidiopathic Current treatments: Treat
symptoms, reduce frequency Surgical resectioning
- Slide 45
- Effects of IBD Severe inflammation, perforation of intestinal
epithelium Strictures, fistulae, toxic megacolon, perianal disease
Arthritis common, may be unrelated Increased risk of cancer,
infection
- Slide 46
- Oxidative Stress in Autoimmune Disease Excessive oxidative
stress is thought to have an important role in the pathogenesis of
many autoimmune diseases Enhances inflammation, induce apoptotic
cell death, disrupt signal pathways Seen in diseases such as: RA
SLE IBD MS