Increased Levels of Progerin Observed in Overweight Individuals

Progerin is the malformed version of LMNA, a protein vital to the structure of the cell nucleus. It is the cause of progeria, a rare condition that has the superficial appearance of greatly accelerated aging. It isn't aging, however, but rather an enormous burden of cellular damage and dysfunction resulting from structural issues in the cell nucleus that affect near all forms of function. In normal aging, there is also an enormous burden of damage and dysfunction, but this arises from a completely different mix of issues. Some of the end results, such as cardiovascular disease, are somewhat similar, but one can't compare the two if interested in first causes.

In the case of patients with progeria, the LMNA gene is mutated, resulting in large amounts of progerin. One of the interesting observations made over the past decade is that some tiny fraction of LMNA is malformed in older people without progeria, however, and it has been suggested that this may contribute to the aging progress. As for many such mechanisms, the question is whether or not its contribution is significant in comparison to that resulting from the various other forms of disarray in aging tissues. That question has not been resolved. The easiest way to do so would be to find an efficient way to remove or block the activity of all progerin and observe the results, but that has yet to take place.

In the open access paper noted here, researchers report on the interesting observation that overweight individuals have higher levels of progerin. Being overweight does in fact accelerate most of the processes of aging. Visceral fat tissue is metabolically active, and generates chronic inflammation through a range of different mechanisms, from increased numbers of senescent cells through to inappropriate signaling on the part of normal fat cells. Inflammation drives the progression of many forms of age-related disease. Again we might ask the question: given this sizable contribution, is the presence of progerin in the observed amounts significant? Answers will remain speculative until such time as the progerin can be removed.

High Body Mass Index is Associated with Elevated Blood Levels of Progerin mRNA

Excess weight is growing in frequency globally. Obesity is associated with morbidity and premature mortality and represents a major risk factor for many diseases especially cardiovascular disease. It is linked to a significant decrease in life expectancy of 5-10 years in comparison to persons with Body-Mass-Index (BMI) between 22.5 to 24.9. An elevated BMI, adipose tissue and muscular fat depositions, respectively, have been associated with aging. Aging is defined as deterioration of cellular and organ function with time related to many physiologic and phenotypical changes and represents the strongest risk factor for myocardial infarction, stroke, diabetes, and cancer. Therefore, premature aging-like syndromes such as Hutchinson-Gilford progeria syndrome (HGPS) are of particular interest in exploring pathophysiological changes of aging processes related to cardiovascular disease.

HGPS is based on mutations influencing the precise encoding and processing of lamin A (LMNA) an important filament protein in the nucleus of eukaryotic cells. LMNA is involved in the correct forming of a filamentous meshwork between chromatin and the nuclear membrane, keeping the nuclear envelope upright, which is essential to regulate processes like DNA replication, DNA repair, and RNA transcription. Individuals suffering from HGPS exhibit early cardiovascular atherosclerosis and often die due to heart attack and stroke as teenagers. Toward the end of life, HGPS patients also suffer from heart failure due to cardiac fibrosis and cardiomegaly.

In most HGPS cases, a single point mutation activates a cryptic splicing site causing the production of 50 amino acids truncated prelamin A called progerin. Progerin lacks the cleavage site for zinc-metalloproteinase (ZMPSTE24) resulting in accumulation in the nucleus, leading to disturbed lamina, telomere and DNA damages, apoptosis, early cellular senescence, and finally to deterioration of organ function. Astonishingly, it was shown that low amounts of progerin mRNA derived by alternative splicing are also expressed in healthy individuals leading to the discussion of the role of progerin in normal aging by various groups. Since obesity and premature aging are both accompanied with an increased cardiovascular morbidity and mortality, we aimed to investigate the association of BMI with respect to progerin mRNA expression in the blood of individuals with known cardiovascular disease.

This study shows that mRNA levels of the aging related lamin A splice variant progerin, associated with premature aging in HGPS, were significantly upregulated in subjects with BMI ≥ 25 kg/m2. Moreover, our data revealed a significantly positive correlation of BMI with progerin mRNA. These data provide to our knowledge for the first-time evidence for a possible involvement of progerin in previously observed accelerated aging of overweight and obese individuals potentially limiting their longevity. Our results also showed that progerin mRNA was positively correlated with C-reactive protein (CRP). This might suggest an association of progerin with an inflammatory response triggering accelerated aging. Moreover, we found an increase of the acute phase protein CRP in patients with BMI ≥ 25, indicating a higher systemic inflammatory status in the overweight group. This is consistent with prior findings where obesity was considered to predispose to local and systemic inflammation with ongoing activation of immune cells.

Comments

Hi there, Just a 2 cents. TL DR: It's back (to back) to oxidative stress.

I think I've figured it now (although I think I do but oftenly I don't) about telomeres/telomerase. It has been so conflictual in terms of results. But, now, I guess I've 'telomerized' it (get it/gotten it). Telomerase is an enzyme complex, it is hTERT the transcript, hTERC the catalytic subunity/telomerase RNA template that is used to add telomeric DNA. It allows infinite replicative lifespan of cells via elongating their telomeres, meaning infinite replicative bouts and avoiding replicative senescence/Leonard Hayflick replicative limit. But, then, why do animals that express telomerase or even have higher levels of it still die like normal...

I guess thus telomerase, is just not enough or not activited enough/expressed enough/in enough gene copy numbers to matter at old age. And telomeres are most an antagonistic pleitropic element to curb cancer and safeguard 'health'/chromosomal integrity.

Like when TG-TERT mice obtain TERT they live a regular lifespan/average, an improved healthspan, not much in terms of longevity (one study showed 20% lifespan media extension)...

If it keeps on adding telomeres (in one study, elevation of telomerase in humans make about 150 bp each 4 months (the volunteers took herbs that activate telomerase (astragalus, ginseng, and many others..to try to boost telomerase)...4 months later, their telomeres went up from 8.3kb to 8.44kb...thus roughly 150bp (150 base pairs telomeric DNA nucleotides), this demonstrates that in humans, telomerase increases about 40-50bp/month..speed. In one year time that would mean 350bp; and in 10 years, 3500bps; or 3.5kbps extra; which in human life is roughly 40-50 years of life.

The study in mouse, foud about the same, and the mice just lived an extra 20% or notthing, just average but improved 'healthspan'...

This means that telomere elongation can be uncoupled from longevity and that it's not so much their length that matters but rather How Quick they go down (the rate of telomere shortening, irrespective of the length of the telomeres).

The rate of shortening is better predictor because it demonstrates 'oxidative stress' exposure if really fast shortening; which can make 'sudden' senescence, and hence cause disease - even in Tall telomeres.

It was demonstrated in dogs vs mice vs humans....dogs lose 500bp/year, mice lose +2000bp/year, humans lose 50bp/year, and HGPS progeria people lose 500bp/year...

Dogs live 15 years (500bp), mice live 3 years (2000bp), humans live max 122 years (50bp), HGPS people live 15 years (500bp). A perfect correlation between speed of loss of telomeres and longevity. In fact, dogs live as long as HGPS people - and Both lose telomeres at the same speed (500bp/year), and live the same lengthspan (15 years).

Thus, it's not so much telomeres the problem (telomeres can cause cell cycle arrest by DDR/checkpoint/telomeric signal)..

the problem, rather, is oxidative stress and that is at the 'mitochondrial level' where ROS are.
Mitochondrial ROS (in many organs) correlate to Maximal Lifespan in many mammals, or rather, the Consumption of ROS is what determines lifespan (besides the susceptibility of membrane to lipid peroxidation products created of ROS exposure at ETC Complex I-V)...The way I see it only 1000-folds increase in telomerase RNA/catalytic subnunit, not just TERT transcript, but the actual RNA 'template' 'filling' the telomeres like 'jenga blocks on top of jenga tower'...could possibly extend lifespan..yet that is not even assured, because certain animals die with long telomeres (like mice..or albatros/leech petrel's...these birds see an Increase of Telomere with age..and they die around 30 years old...)...
this means, oxidative stress, at the mitos, is where Really it matters (outside of the epigenome). They see correlates of epigenome and telomeres...but even there there is ambiguity; longer telomeres mean a longer lifespan (children born to older fathers with longer sperm telomeres inherit longer telomeres..from birth...and studies showed that in humans, telomeres at birth/earliest age determines 'Rest of Lifespan'...so if you born with more, and you age slowly, you have 'more to work with', later. THat means preserving 'health' longer, allowing you a longer HealthSpan.

But telomeres incraese themselves will not allow you to go Above Maximum Lifespan...because as said, oxidative stress, ends up more prominent important...and in high age, the oxidative stress may come Very Quickly, and telomerase just can't abate it anymore - Even If the Teloemres are Taller...
Taller telomeres mean less inflammation and more cell division...but Rate of Telomere Shortening is What is Important and Determines 'Oxidative Stress' 'sudden' changes....it's why you may see mortality despite tall telomeres (like in these long lived birds with long telomeres); it's not Just About long telomeres, but it's about keep oxidative stress at lowest possible, and then telomeres can keep on rising as telomerase adds up telomeric DNA on them.

The studies also showed that telomerase activation means a reduction in total number of Short(est) telomeres...because short telomeres are highly critical and can cause widespread disease/mutations/dysfunction/senesnce since cancer hijacking arrives around those low 2-kb short telomeres 'uncapped/unstable/Demethylated'.

This means, oxidative stress is far more consequential 'in longevity' that we think. The mitochondrial ROS is crucial for that, because that is where it all starts; with age there is a pro-oxidant shift that happens and mitochondrial ROS can elevate Multiple times...this means a very oxidized redox milieu; in fact, GSH:GSSG ratio/GSH thiols pools in mitos are Very tuned and Control the mtROS emission; loss of GSH in mitos mean mito membrane potential depolarization and then mPTP/loss of cytochrome C, cell will apoptose. IN turn NAD+/NAD(H)/NAD(P)H will be changed and there will be a loss of dinucleotide NAD; if this is reduced, thant the redox can no longer 'protect mitochondrial membranes' from ROS causing volatile/cascade peroxidation chains (MDA/TBARS/ALEs), which will cause massive damage to the mitochondrial DNA in the mito itself (8-oxodG lesions, mutations and then, base pair deletions; that is when the mtDNA becomes 'emptied' and completely dysfunctional by lacking 'DNA' content 'deleted' from oxidative insults/attacks dur to elevated ROS production IMM(Inner Mitochondrial Membrane) ETC Complexes I-V). And it's not so much - 'elevated ROS' - it's ABSENCE OF QUENCHING/CONSUMPTION/DETOXIFYING of ROS, the problem, and even also absence of repair of mtDNA (ATM/BER/NER/WRN helicase cannot excise DNA lesions anymore and do proper DNA repair; thus 8-oxodG in mtDNA and in nucleus, y-H2AX foci in telomeres; then SSBs/DSBs (single strand breaks/double strand breaks) of DNA itself ('DNA Frag'(mentation)).

Mice showed much less capability to 'withstand' ROS elevation with age, than human mitos, because human's 'Consumed' much more ROS than mice's mitos. That means preservation of a reduced redox and correct sulfur thiol ratio. I greatly underestimated how the source of ROS mitos contributes to aging; it's really that big and important on Longevity...not talking just 'health' but Maximum Lifespan/Longevity; the epigenome is the other element; but the 'damaging' one that causes a reduce Longevity is at the mitochondrial level, and, at the mito redox level too; since, mitos without redox quenching are 100% vulnerable and would apoptose Immediately (as seen with GSH depletion (by ROS/GSSG accumulation/oxidizing the redox milieu) causing mPTP instantaneously and Irreversebly; the only step that is reversible is BEFORE mPTP pore opening...once to mPTP it's irreversible loss of Cyt.C 'pouring' through the 'pore holes', as the mito 'purges' itself in a 'self-suicide' signal). At the 'cellular level' the cell will apoptose or enter senescence depending on ATP levels from this mito crisis; since both apoptosis and senescence 'cost ATP' to instigate; otherwise, it'S necrosis, is lack of ATP.

What I'm trying to say, from all this, is that what is more important with aging is making sure telomere attrition rate is the smallest possible because it means 'overall' low oxidative stress in teh body; which is a good thing For Longevity, not just health. And that's because oxidative stress ends up causing these many Oxidative insults from DNA frags, MDA aldehydes, carbonyls, lipofuscin and what not; this causes clear 'macro-molecular' damage to everything, including outside in ECM. Then this means residues (lipofuscin, junk, proteasome/Lysosome mass enlargment clogging), which contribute to incapacity of 'ridding of the junk - because loaded with it' as it accumulates from all the damaging insults at mito level.

Just 2 cents.

PS: In this study, Progerin is a cause and very toxic, hence makes complete chromosomal assembly instability and remodelling...dysfunction wide. The whole body then just has constant oxidative stress (losing 500bp/year in HGPS progeria is a clear sign of oxidative stress everywhere and oxidizability rising with little to no quenching/detoxifying of it (HGPS redox is completely destabilized and up to 50+ mV higher, demonstrating oxidation wide, especially in their mitos, making cells age very fast).

Posted by: CANanonymity at May 4th, 2019 2:02 AM

PS: And come to think of it, CR (Calorie Resctriction) is the Only True Intervention that Truly extends both average and maximum lifespan; and it reduces oxidative stress/DNA 8-oxodG lesions (over long term CR), this means truly that damage is not Just health, it Really is Also Longevity; depending on the type of damage (DNA..)/where (mitos, nucleus, telomeres)...etc...this can explain why CR is capable of extending lifespan...but hTERT therapy can't that much in mouse. BEcause CR is capable of stopping macro-molecular damage due to rising oxidative stress at mitos. Telomerase does reduce/stabilize ROS and has double role, but it is Nowhere near as strong as redox detoxifying enzymes/repair systems such Phase II enzymes, or NAD+ with electron donation and SIR/DAF/FOXOS..these are Crucial for repair/quenching/consumption of ROS, they are in 'permanent mode' 'parked' in mitos, to protect them from a very worse fate than it is now. CR just improves this detoxyfying, repairing, junk removing, quenching/consumption of ROS by redox 'reduced' state (gsh and thioredoxin/peroxiredoxin/glutaredoxin..)

Posted by: CANanonymity at May 4th, 2019 2:12 AM

Hi Norse! Just a 2 cents.

Great article...it's pretty surprising (or not so surprising.. in a kind of 'I told you/this was coming' way..)..

Industrialized/developped countries, with more wealth, show clear fertility decline; and as the article shows, as time goes; the more rich it is the less new children there are.

If we did reach LEV, of course, that would make an immense impact on population numbers; but, if no new children anymore ... then this greatly diminishes the whole 'overpopulation' thing.

It means a 'fixed' number of people living much much longer; and no New Arrivals (children).

I'm just talking of developped countries of course...because in third world countries they still make many children; it's there that it would be problematic, if LEV ever did become and became available there; Many would want it and by their sheer numbers this might cause overpopulation - just there..the people would emigrate elsewhere because it would be 'so jammed pack'/population dense over there.

Kind of like China (1 Billion people), India (+1 Billion people already), Africa at large (an extra or 2 Billion), and other Ultra-Dense Mega Cities (Tokyo with some many milllions of people there, it's so dense, almost to point of explosion), etc. There would be probably be emigrating to surroundings, just 'to spread' the rising population.

But, in the end, global fertility decline will 'balance things out' about a 'possible overpopulation' from LEV. If it doesn't, we will have to seek other solutions, like maybe getting on a another planet, and populating it there because no more place on Earth. And even there, there is still Lots of place on Earth that there is 0 human population..it's just mostly 'inhabitable'...we may have to make it 'habitable' for the rising number of people 'who live 'forever''..and don't die like humans in past generations. I guess things 'even out' overpopulation (LEV) vs global fertility decline = no change.
But only in places of low birthing (developped/rich nations...poorer nations continue to have Huge families of like 10 children each...that would make overpopulation). All in all, nothing so serious to worry about 'overpopulation'; Earth has already 7 billion people and there are trillions of animals on it - everything is still working; there could be another 50 billion people and it would still work; of course that would tax Earth's resources but this is why we must build new technologies/new ways to 'not depend on Earth' for resources (resource recycling/autonomy); if we can 'make food' in a laboratory, then, most problems will be solved (starting with the biggest one, poverty/famine/unaccess of hospital health cares).

Just a 2 cents.

Posted by: CANanonymity at May 4th, 2019 11:53 AM

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