Those studies seem to indicate to me that too much calcium in cells downregulate telomerase:
Role for Telomerase in Listeria monocytogenes Infection:
In the present study, we reveal that downregulation of hTERT impairs Listeria infection and that L. monocytogenes induces a decrease in hTERT levels. This diminution is triggered by listeriolysin O (LLO), a pore-forming toxin secreted by L. monocytogenes. The decrease in hTERT levels is stimulated by calcium influx through LLO pores at the level of the host plasma membrane. Our study demonstrates for the first time a regulation of the catalytic subunit of telomerase by bacteria and highlights a role for telomerase in infection
A Novel Regulator of Telomerase. S100A8 Mediates Differentiation-Dependent and Calcium-Induced Inhibition of Telomerase Activity in the Human Epidermal Keratinocyte Line HaCaT
Recently we reported a differentiation-dependent inhibition of telomerase activity in human epidermis. Consistent with this observation we found that in keratinocyte cultures calcium-induced differentiation correlates with a decline in telomerase activity. To get further support for a role of calcium in the regulation of telomerase and to elucidate the underlying molecular mechanisms we investigated the effect of calcium on telomerase in the human epidermal keratinocyte line HaCaT. Treatment with thapsigargin, which increases intracellular calcium concentrations, inhibited telomerase activity without down-regulating the expression of hTERT (human telomerase reverse transcriptase). This observation together with the fact that increasing calcium reduced telomerase activity in cell-free extracts suggests that calcium directly interacts with the telomerase complex. This interaction could be mediated by the calcium-binding protein S100A8 as indicated by its ability to mimic the inhibitory effect of calcium. S100A8-induced reduction in telomerase activity was abrogated by S100A9. The ratio of both proteins remained constant in cells treated with thapsigargin, but their interactions were altered similarly in intact cells after thapsigargin treatment and in cell-free extracts in response to calcium. We hypothesize that calcium binds to S100A8/S100A9 complexes and alters their composition, thus enabling S100A8 to interact with the telomerase complex and inhibit its activity.
Also some studies have shown that a higher Mg/Ca ratio are correlated with reduced all cause mortality.
Association of Serum Magnesium and Calcium - Magnesium Ratio with Mortality in Patients with Coronary Artery Disease (P18-090-19)
Low serum Mg concentrations and high Ca-Mg ratio were significantly associated with an increased risk of all-cause and CVD mortality in Chinese patients with CAD, independent of traditional CVD risk factors.
Magnesium has many health benefits, but maybe also magnesium competes with Ca for absorption, so perhaps more Mg reduces Ca in the cells, which leads to more telomerase activation.
This leads me to the following question regarding vitamin D effect on telomerase. Since Vit. D increases absorption of Ca both by the gut but also by the cells, would there be a negative feedback where calcium reduces the activation of telomerase by vit D? And if yes, how would it be possible to reduce the uptake of calcium by the cells?
I found in the book "Calcium and Cellular Secretion" Page 36 that manganese might be able to reduce Ca absoption in the cells, I'm not sure I understood it properly. I'm sorry it doesn't seem to be possible to cut and paste a text from a book. Please google for it.
Mn also has a positive effect on telomerase independant of this, so it could be a good choice as a Ca inhibitor.
Since I am a new member I can't post links so please google the studies titles if you want to read the whole thing.
