Mtc Final Exam

Front 1

Thyroid Hormone Regulation

Back 1

Hypothal ~> TRH ~> Ant Pit. ~> TSH ~> ThyG ~> T3/T4

Front 2

Tyrosine + Iodinated Derivatives

Back 2

Tyrosine + DIT + DIT = T4

Tyrosine + MIT + DIT = T3

Tyrosine + DIT + MIT = Reverse T3

Front 3

Deiodinase Enzymes

Back 3

D1/D2 = T4 ~> T3 (Expressed in Heart + Muscle)

D3 = T3 ~> Reverse T3

Front 4

Main Effects of Thyroid Hormone

Back 4

1)Increased Oxygen Consumption (most tissues)

i) more ATP Utilizing protein

ii) more ATP Synthesizing proteins (from free ADP)

iii) higher BMR

2)Growth/CNS Development

i) dwarfis/cog impairments if LOW

3)Cardiovascular System

i) Cardiac Hypertrophy from increased Beta -1-Adrenergic receptors

Front 5

WILLIAM & HOLLOSZY

MTC/MUSCLE & Thyroidtoxicosis

Back 5

Different muscle fiber types respond differently

ST better than FT ~> higher [MTC] in ST

Front 6

TERJUNG & KOENER

Thyroidectomized Rats & Exercise

Back 6

(Norm Trained/Untrained & TZD Trained/Untrained)

~TDZ-sedentary rats had 1/2 as much [MTC] than Norm-Sedentary

~No Sig Diff between Norm-Trained / TDZ-Trained in [MTC]

therefore T3 important for maintenance not exercise

Front 7

IRRCHER #1

Timed Effects of T3 on AMPK/p38/PGC1a in

-Soleus (S) // Plantaris (P) // Heart (H)

Back 7

p38 - S: doubled

P: doubled first 2 hours then decreased

H: increased over time

AMPK - S: doubled up until 4 hours

P: doubled first 2 hours then decreased

H: Not Significant

PGC1a - Not Significant in all 3

therefore T3 rapidly modifies Kinase activity in tissue specific fashion

Front 8

IRRCHER #1

Possible Mechanisms of T3-Induced Gene Expression

Back 8

1) Direct binding of T3 on Thyroid Response Element

2) Non-Genomic binding of T3 on TF (p38/AMPK)

3) Genomic binding of TF containing T.RE in promotor

Front 9

ROBINSON & HOOD

T3 & Effects On mtDNA Diseases

Back 9

~COX activity increased for patients

~No significant difference in MTC mass b/w groups

~[ROS] increased in patients alongside higher [MnSOD]

No effect on PGC1a

Front 10

IRRCHER & ADHIHETTY

PGC1a Protein levels with CCA/Denervation over time

Back 10

~50/60% increase >3days // stayed = ~5/7days

~> decrease on 10th day

~Rapid drop in protein levels + COX activity in 5days

Front 11

BAAR HOLLOSZEY

Acute Ex+Rest on PGC1a/NRF1-2 Protein Levels

Back 11

~ 2 fold increase in protein levels

+ binding of NRF1-2 on DNA

Front 12

CALVO PRESENTATION

PGC1a +/+ on Exercise Perf & MTC content

Back 12

+/+ mice had higher

- FA oxidation + transport

- Oxidative phosphorylation

- CHO metabolism

- Peak VO2

- Total VO2 ~> Work Ability

-- Lower RER ~> Better FA Oxidation

Front 13

SANDRI

PGC1a +/+ & Denervation induced Atrophy

Back 13

~ Denervated WT atrophied while

~ (+/+) protected 2 fold against atrophy

+/+ block FOXO-3 from binding to Atrogenes

Front 14

Atrogenes

Back 14

Activate during disuse, FOXO-3 bind to Atrogin-1

stimulates protein degradation

Front 15

WINDER

AMPK Importance on PGC1a in FTR/FTW/STR

Back 15

Citrate Synthase measured in muscle fibres injected with 4weeks of AICAR

FTW/FTR sig. increased but not STR

~> STR has high [MTC]

Front 16

AMPK VS mTOR

Back 16

AMPK activated by

~ Increased Calcium from contractions

~ high AMP to low ATP ratio

AMPK phosphorylates TSC2 which inhibits mTOR

Front 17

IRRCHER #2

AICAR Regulation of MTC-BG

Back 17

Increase AICAR ~> Increase PGC1a levels w/ same increase in AMPK

Front 18

IRRCHER #2

Human PGC1a Promoter Deletion Constructs

Effect of AICAR on PGC1a

Back 18

(472-821) see increased response to AICAR

Oglionucleotide made ~> Gel-Shift Assay ran on binding sites

TF bound to EBOX/GATA when AICAR increased

Front 19

IRRCHER #2

Effect of AICAR on PGC1a continued

GATA/EBOX

Back 19

4 proteins bind to GATA/EBOX

MyoD // Myogenin // USF1-2 // C-Myc

AICAR ~> 1 of these to bind more to the EBOX

Super Shift Gel Assay done with radioactive 32P label

~> USF-1 only protein to shift of the 4

Therefore AMPK ~> Phosph USF-1 to increase TF of PGC1a

Front 20

MTC Morphology

~Protein Review

Back 20

Fusion Proteins

~Mfn-1 & 2

~OPA1

Fission Proteins

~Fis1

~Drp1

Front 21

French Paper

MFN expression Post exercise

Back 21

Results fond increased mRNA expression post exercise @ 24H

Front 22

MFN-2 in Obese rats/humans

Back 22

Both groups show sig. decrease in MFN-2

~> decreased MFN-2 = decreased MTC-Network = decreased lipid metabolism

With French paper taken into account ~> Exercise ameliorates adverse effects of obesity

Front 23

SADIA IQBALL STUDY

CCA // Denervation // Aging on Fis:Fus Proteins

Back 23

i) CCA: Fission proteins = N.S

Fusion proteins = Significant

ii) Denervation: Both Fis/Fus decrease

favour Fis over Fus

iii) Aging: Fis proteins increase, favour over Fus

MTC Depth/Size: both increase with i) but decrease with ii) & iii)

Front 24

SCHATZ

Fundamentals of Protein Import into MTC

Back 24

1) Precursor contain pre-sequence ~> Matrix

2) ATP + Chaperones unfold + Begin interaction with TOM

3) -150mV difference in charge translocates protein

4) Complete translocation + cleaving of pre-sequence

5) Re-Folding by Intra-MTC chaperones ~> Targeting to part of cell

Front 25

Measuring Pre-Cursor Protein

In Vitro

Back 25

1) Plasmid Vector with

i) Bacterial Promoter Region + Coding Sequence (MDH)

2) Add RNA-Polymerase for Transcription in vivo

3) Add Cell Extract for Translation in vivo

~Ribosomes, tRNA, 20 A.A.

~35S-Methionone Radioactive Tracer

4) Add MTC & Incubate

5) Separate proteins on gel base

6) Incubate gel w/ film for Radioactive bands

7) Pre-Cursor at top w/ imported father down

Front 26

TAKAHASHI & HOOD

Import into Matrix - SS VS IMF MTC

Back 26

Difference between SS & IMF

~IMF - higher protein import at all 5min intervals

Front 27

TAKAHASHI - GORDON - JOSEPH

CCA on MTC Protein Import

Back 27

Import Rate increases

Protein Import Machinery increases

CCA increases rate because machinery present increases

Front 28

SINGH & HOOD

MTC Protein Import & Denervation

Back 28

Denervation causes

~Decreased State 3 Respiration

~Decreased PIM Expression

~Increased ROS production

i) Apoptosis, Autophagy, Protein Degradation as result

Leading to Decreased PIM Expression ~> Leading to lower [MTC]

Leading to Muscle Atrophy

Front 29

Protein Import in regard to Gene Expression

Back 29

Chronic exercisers have highest protein import rate because of higher PIM expression/Rate

Front 30

YUAN ZHANG

BAX/BAK in Protein Import

Back 30

(-/-) BAX/BAK reduces import into matrix increasing ROS ~> Inducing gene expression

Front 31

YUAN ZHANG

BAX/BAK Protein Import - Exercise Effects

Back 31

Exercise increases MTC-BG enough to raise COX activity in (-/-) BUT

~ (-/-) had lower endurance/work ability

Exercise saved import rate + fixes problems with machinery

Front 32

ADHIHETTY & HOOD

MTC Mediated Apoptosis

~Caspase Dependent Pathway

Back 32

~BAX creates tetromer channel on OM allowing CytC escape

~ROS allows CytC unbinding from Cardiolipin

i) CytC can escape through mtPTP

~CytC binds to apoptosome ~> Activate Caspase Casecade

~Casp-3 enters Nucleus = DNA Fragmentation

HSP70 inhibits cascade from beginning

Front 33

ADHIHETTY & HOOD

MTC Mediated Apoptosis

~Caspase Independent Pathway

Back 33

~ROS regulates mtPTP ~> too high opens up

~Organelle swells with H20 releasing

i) AIF & EndoG

~Enter nucleus = DNA Fragmentation

HSP70 inhibits AIF/EndoG

Front 34

BAINES

Causes of mtPTP opening up

Back 34

1) Membrane Potential Dissipation

2) Reduced ATP-Synthesis

3) Increased ROS production

4) Organelle Swelling/Rupture

Front 35

Coincidental Changes in Apoptotic Susceptibility in IMF/SS MTC with Denervation

Back 35

Huge increase in ROS from SS VS small change in IMF

~> MnSOD stayed higher longer in IMF (more stable population of MTC)

Front 36

Apoptosis as contributing factor in cell death

Back 36

AIF: Elevated >5 days and plateau'd

Casp-3: Significant increase in 8 days

BAX:Bcl-2 - Inverse relationship (More pore opening vs less poor inhibition)

Front 37

mtPTP Kinetics with Denervation

Back 37

Vmax - speed of poor opens faster

Vmax (t) - decreases = less time to re-open

Front 38

ALWAY

Exercise's Protective Effects Against Apoptosis

Back 38

Bcl-2 increase 50% ~> + inhibition

BAX not significant

Front 39

YALNSHTEIN & HOOD

Endurance Training on Apoptotic Susceptibility

in Soleus (S) & Heart (H)

Back 39

S: BAX:Bcl-2 decreases as well as AIF

H: BAX:Bcl-2 decrease as well as AIF

EX Attenuates apoptotic signalling

Front 40

ADHIHETTY

CCA ON CytC Release (IMF/SS - MTC)

Back 40

1) Decrease BAX:Bcl-2

~higher inhibition

2) Increase Vmax (t)

~pore closed more

3) Increased Cardiolipin

~CytC bound more

Front 41

What 5 Factors Occur with Age?

Back 41

1) Decreased [MTC] + Function

2) Increased Apoptotic Susceptibility

3) Decreased Protein Import

4) Increased Sarcopenia

5) Decreased Exercise Adaptation

Front 42

Sarcopenia

Back 42

1-2% >50 Years old

i) decreased [MTC]

ii) dysfunctional MTC (High ROS/Low Respiration)

iii) increased MTC-Mediated Apoptosis

Front 43

CONLEY

Sarcopenia In The Muscle

Back 43

Decreased

1) oxidative capacity (p/gram muscle)

2) [MTC] vol/p/gram muscle

3) oxidative capacity (p/MTC)

Front 44

CHABI & HOOD

Biochemical Indices of [MTC] w/ Age

In Soleus (S) // Plantaris (P)

Back 44

COX Activity: 30% reduction in S & P

PGC1a Protein Levels: Decreased in both

i) higher in S ~> more MTC

Front 45

HUANG & HOOD

Age on Processing & Import of Matrix Proteins

Back 45

No difference between young/old on import

Difference in CAPACITY

~> Cytsolic changes in old degrade pre-cursor

proteins faster

Front 46

MTC & ROS Production - Causes

Back 46

1) mtDNA Damage

2) Apoptotic Protein Release

3) Increased Pore opening

Front 47

ROS Production & Anti-Oxidant Enzymes w/

Age

Back 47

ROS increases with age but no increase from [Anti-Oxidant Enz]

Front 48

mtDNA Mutations in Aged Human Tissue

Back 48

Mutations/common deletions occur @ 60-70 Years of age

BUT point mutations in mtDNA occur at 40-60 years of age PRIOR to mutations

Front 49

Mutations in Aged muscle - COX & SDH

Back 49

Old muscle more COX negative so nucleus overcompensates with SDH expression

Front 50

Aged Muscle Vs Young Muscle

Back 50

Endurance - Decreased Tension w/ increasing contraction time in old

Strength - Max force lower on gram basis

Sarcopenia - in rats (36months) higher

~except in Hypertrophy of heart

Front 51

Aging Flow Explanation

Back 51

As you age you increase the MTC ROS production meaning there's more apoptotic protein release. The more proteins released the higher the mtDNA damage is which causes more ROS alongside a increase in Nuclear DNA fragmentation creating a positive feedback loop . Once your mtDNA is damaged it increases Nuclear damage, atrophying the whole muscle fiber and accounts for the decrease in muscle mass

Front 52

Sarcopenia Contributions

Back 52

1) Loss of strength

2) Decreased metabolic rate

3) Decreased Aerobic Capacity

4) Decreased Functionality

Front 53

Evaluating Fatigue in Old vs Young muscle with CCA

Back 53

~> both groups had lower fatigue in tension over time with CCA but young had GREATER improvement

Old doesn't respond as well (1/2 fold as well)

~COX Activity: 15% vs 25% in young

~Protein Import: faster in young-CCA but no increase in old, just attenuates age-associated decline

Front 54

CCA Induced Expression of MTC-BG

Regulatory Proteins

Back 54

All increase in both young and old BUT

Old show MUCH less adaptation than young

Front 55

REZNICK

AMPK in older CCA animals

Back 55

no significant different in old animals with increased AMPK activity

Front 56

ROS Production and Exercise in Old Animals

Back 56

Exercise COMPLETELY relieves ROS stress in BOTH young/old

Front 57

DNA Fragmentation & CCA in Old Animals

Back 57

2-3 fold decrease in Fragmentation in Old animals with CCA

Front 58

CONCLUSION

Back 58

1) Aged Skeletal Muscle = reduced adaptive plasticity toward MTC-BG

i) Reduced signalling

ii) Reduced Gene transcription

2) CCA attenuates DNA Fragmentation

3) Old Muscle CAN adapt ~> Needs stronger stim/duration

Front 59

Group 1

Resistance Exercise on MTC Function

Back 59

increased State 3 respiration

increased resp capacity via higher uncoupling

Front 60

Group 2

Acute Exercise Remodels MTC Membrane

Interactions

Back 60

no change shape/size/structure

Electron Density Contact Sites increased

~> (in IMF 93% vs 16% SS)

~> doesn't mean they fuse

Front 61

Group 3

CamKII on MTC // Contractile

Back 61

Doesn't influence MTC ~> mTOR pathway

Type II Myosin Heavy Chain

influenced contractile ability

Front 62

Group 4

AMPK - R419 Activity

Back 62

R419

improves glucose tolerance (AMPK Independent)

improved exercise capacity (AMPK Dependent)

improved insulin sensitivity (AMPK Independent)

improved glucose

Front 63

Group 5

Apoptosis/Necrosis & Muscle Fiber loss in Aged Rats

Back 63

3x more apoptotic factors in aged

9x more necrosis factors in aged

60% markers were related to Enzymatic Issues (ETC)

Longer ETC issues = prone to atrophy

tBid, PUMA, cleaved Casp-3 (APOP markers)

c5b-9 & CD68 (Necrotic markers)

Less COX ~> SDH compensation

mtDNA mutations increases COX4 issues increasing APOP/Necrotic markers

Front 64

Group 6

Mitophagy and EndoG

Back 64

Decreased mitophagy leaves sensitive mtPTP decreases Parking VDAC ratio --> endo g releases and kills

Front 65

Group 7

Thyroid Hormone of Autophagy

Back 65

Decreased mTOR

Increased mRNA PGC1a expression

Increased AMPK

Increased ROS