This is a really interesting paper as it looks at the metabolism of differentiation. Although it does not prove the same or a similar mechanism operates for all mammallian cells, it is reasonble to hypothesise that there will be similarities.
Basically as the process of differentiation occurs masses of citrate comes out of the mitochondria via the SLC25A1 protein (aka the mitochondrial citrate carrier). This is needed for histone acetylation. Once the cell has differentiated then the level of SLC25A1 goes down.
My hypothesis is that SASP through IL-10 and operating via the JAK Stat and reduced levels of NF Kappa B causes a restraint on SLC25A1 levels in some cells which prevent them from differentiating and causing diseases like osteoporosis.
However, it is nice to see further details about this process.
I appreciate your focus on this. One of the reasons I do the Wim Hof breathing technique daily is that it increases IL10 and I’m very focused on any and all strategies to reduce inflammation (as I have a chronic inflammatory condition- MS).
For practical purposes, how do we buy citrate? If you google citrate, it leads to you magnesium citrate whereas you seem to be taking various forms of citrate. There are also very few podcasts or popular papers out there that discuss “citrate” as a topic.
And if one’s main source is magnesium citrate, what would be the dose? If it is not sufficient form or source, can you elaborate on how to obtain other form, in practicality? I googled Amazon and there is no “citrate” supplement as it seems.
I must admit I’m a bit confused about this topic. It’s probably due to it being a new topic for me and I haven’t done sufficient research yet. But…
I understand that your basic premise is that by flooding the cell with citrate, the cell is able to make more “fuel” to drive the transcription and translation mechanisms that together result in protein synthesis.
Yet, today I read a paper about the mINDY gene, which acts to import citrate into the cells. Surprisingly to me, it is loss of function mutations (or knockouts in the case of mouse models) in this gene that results in extended LS and healthspan. In fact, the benefits are very similar to CR (which is essentially what it is).
I’m at a loss to reconcile these 2 trains of thought.
Any enlightenment would be appreciated.
mINDY aka SLC13A5 is only expressed in a limited number of cells. The experiments I have read are with fruit flies and mice, but in essence if you don’t burn up the citrate in the liver (which is where mINDY is mainly expressed) then there is more citrate for other cells.
There are subtle points about how citrate gets into cells. There are three well known transport proteins SLC13A2, SLC13A3 and SLC13A5, but there is also evidence from experiments with Carbon 13 flagged citrate that it can generally get into cells, but not that quickly.
Acetyl-CoA acts as a form of indicator of energy levels. If there is a limit on acetyl-CoA this holds back transcription (sensibly because there won’t be the spare ATP for translation)
I would still be very wary of citrate supplementation. (See abstract below.) As if that did not ring alarm bells, cancers are known to thrive on excess citrate (note that I am not suggesting a causative role here).
At the very least I hope you monitor your insulin levels.
Dietary citrate acutely induces insulin resistance and markers of liver inflammation in mice
Jessica Ristow Branco, Amanda Moreira Esteves, João Gabriel Bernardo Leandro, Thainá M Demaria, Vilma Godoi, André Marette, Helber da Maia Valença, Manuella Lanzetti, Marie-Line Peyot, Salah Farfari, Marc Prentki, Patricia Zancan, Mauro Sola-Penna
The Journal of Nutritional Biochemistry 98, 108834, 2021
Citrate is widely used as a food additive being part of virtually all processed foods. Although considered inert by most of the regulatory agencies in the world, plasma citrate has been proposed to play immunometabolic functions in multiple tissues through altering a plethora of cellular pathways. Here, we used a short-term alimentary intervention (24 hours) with standard chow supplemented with citrate in amount corresponding to that found in processed foods to evaluate its effects on glucose homeostasis and liver physiology in C57BL/6J mice. Animals supplemented with dietary citrate showed glucose intolerance and insulin resistance as revealed by glucose and insulin tolerance tests. Moreover, animals supplemented with citrate in their food displayed fed and fasted hyperinsulinemia and enhanced insulin secretion during an oral glucose tolerance test. Citrate treatment also amplified glucose-induced insulin secretion in vitro in INS1-E cells. Citrate supplemented animals had increased liver PKCα activity and altered phosphorylation at serine or threonine residues of components of insulin signaling including IRS-1, Akt, GSK-3 and FoxO1. Furthermore, citrate supplementation enhanced the hepatic expression of lipogenic genes suggesting increased de novolipogenesis, a finding that was reproduced after citrate treatment of hepatic FAO cells. Finally, liver inflammation markers were higher in citrate supplemented animals. Overall, the results demonstrate that dietary citrate supplementation in mice causes hyperinsulinemia and insulin resistance both in vivo and in vitro, and therefore call for a note of caution on the use of citrate as a food additive given its potential role in metabolic dysregulation.