Mito Biogenesis 1 Flashcards
What studies demonstrate the importance of mitochondria for health and disease??
Tanaka and Seals (2003) showed aerobic capacity declines with age due to reductions in both max and submax performance
Barazoni et al (2000) showed mitochondrial number decreases with ageing
Conley et al (2000) showed mitochondrial function decreases with ageing.
What papers illustrate that mitochondria are 3D?
Ogata and Yamasaki (1997) removed myofilaments and cell matrix to demonstrate the 3D concept
Jacobs (2006) used fluorescent labelling demonstrate the mitochondrial reticulum in living cells
What is mitochondrial biogenesis!
Term used to describe the adaptive response of the mitochondria to physiological stimuli
Complete mtB represents an increase in mt number, function and capacity, which represents an expansion of the reticulum
What did Koves et al (2005) find?
Subsarcollemal mt are more sensitive to endurance training and play a greater role in FA oxidation.
Found in SS mt that elevated FA oxidation was accompanied by a 48% increase in CS but no change in CPT1
Endurance ex training increases FA oxidation in both pools of MT
What did Holloszy find in 1967 and 1970?
Showed that exercising rodents had higher o2 uptake, RCI and mitochondrial protein number compared to sedentary rodents.
Further showed higher levels of COX and SOX in the exercising rodents in both calf muscles.
In 1970 he again showed enhancement in mitochondrial adaptions with running vs sedentary for nearly all TCA enzymes and also CytC
What did Spina et al 1970 find?
Verified Holloszy’s work, showed that mitochondrial enzymes such as CS and CAT increase in muscle in response to 7-10 days of cycling
What did the key paper from Seo et al (2010) find??
Illustrated how mitochondrial function is regulated in skeletal muscle.
The fine balance between fusion (outer - mfn2 and inner - opa1) and fission (drp1 and fiss1).
Fusion is an increase in mt mass, where fission is an increase in mt number due to the cleaving process where mitophagy occurs.
Discuss the work from Bach et al (2003) on Mfn2??
Overexpression leads to a dramatic increase in the mitochondrial reticulum network in a rat derived muscle cell line
They also showed that deletion of mFn2 led to a reduction in insulin stimulated glucose uptake and reduced mitochondrial respiration in this rat derived muscle cell line.
What did Pagano et al (2014) find?
Acute endurance exercise in mice appears to increase mitochondrial fission (Drp1 phosphorylation) without changing fusion.
Igbal et al (2013) found an abundance of proteins involved in fusion/fission correlates with oxidative capacity, discuss study?
7 days of electrical stimulation increases mitochondrial size and number, and oxidative capacity in addition to increasing OPA1 and MFn2 protein content
Discuss mitochondrial protein changes with age/disuse? (Igbal et al, 2013; Seo et al, 2010)
Igbal - denervation leads to decrease in all mt proteins
- ageing leads to ⬆️fission ⬇️fusion
Seo - fragmented mitochondria ⬆️fission ⬇️fusion
- enlarged mitochondria ⬆️fusion ⬇️fission but both lead to apoptosis
