This paper, which was published on September 14, 2016, examines the effect of N,N-Dimethyltryptamine (DMT) on hypoxia-induced cellular changes. It specifically looks at the role of the Sigma-1 receptor.
Abstract: DMT is capable of reducing cell death when cells are placed in a hypoxic environment. Sigma-1 receptor activity is involved in that effect.
Authors: Attila Szabo, Attila Kovacs, Jordi Riba, Srdjan Djurovic, Eva Rajnavolgyi, and Ede Frecska
The Sigma-1 receptor is known to play a role in cellular responses to hypoxia and DMT is a known ligand for the receptor. DMT’s effect on Sigma-1 has been studied to some degree and this study further explores DMT’s effects to see if it can protect cells during hypoxia.
Here are the cell types that were used:
- Cortical neurons derived from human-induced pluripotent stem cells (iPSCs).
- Monoctye-derived macrophages (moMACs)
- Monocyte-derived dendritic cells (moDCs)
Sigma-1 Expression in iPSC-Derived Neurons
Expression of Sigma-1 hadn’t been investigated in iPSC-derived cortical neurons, whereas it has been looked at in moMACs and moDACs, both of which express high levels of Sigma-1.
The neural stem cells were found to have a low baseline expression level. But, as the cells differentiate into neurons, the expression increases, ultimately reaching a peak at the end of the differentiation.
DMT Boosts Survival During Hypoxia
To see how cells would respond during hypoxia, an environment with 0.5% oxygen was used.
Cell death, more so with the neurons, was observed and it was reduced with DMT. DMT was used at a concentration ranging from 10 – 200 uM, with the efficacy depending on the cell type.
- Neurons (after 6 hours of hypoxia)
- Control = 19% survival
- 10 uM DMT = 31% survival
- 50 uM DMT = 64% survival
Significant beneficial changes were seen with neurons beginning at 10 uM, whereas 50 uM had an effect in moMACs and moDCs. No difference in the MACs/DCs was seen between 50 uM and 200 uM. Also, the survival rate was still relatively high in moMACs and moDCs by the 6 hour mark, though the drop that was seen could be reduced with DMT.
DMT Affects HIF-1a Expression
Hypoxia-inducible factor 1-alpha (HIF-1a) normally increases during hypoxia, a change that can largely be prevented by DMT at 50 uM.
All of the control cells showed higher levels of HIF-1a protein expression after 6 hours of hypoxia. When DMT was used, the increase was much lower.
VEGF (vascular endothelial growth factor), a protein connected with HIF-1a, appears to increase (as seen by measuring mRNA expression) during hypoxia. This change was blunted by DMT as well.
When a non-hypoxic environment is used, DMT has no effect on HIF-1a.
Sigma-1 Is Involved In These Effects
To make sure Sigma-1 is actually involved, two separate methods were employed. First, the Sigma-1 gene was silenced. Second, an antagonist was used.
In the first test, silencing led to the following receptor downregulation:
- Over 93% in neurons
- Over 96% in moMACs
- Over 91% in moDCs
Silencing of the gene got rid of DMT’s ability to boost cell survival during hypoxia. It also blocked the HIF-1a modulation.
Sigma-1 silenced cells treated with DMT did worse in hypoxia than the control cells.
As for the antagonist experiment, BD1063 was used. It successfully blocked DMT’s effect on survival and HIF-1a.
Hypoxia is capable of causing significant cell death in iPSC-derived cortical neurons, moMACs, and moDCs. When DMT is used, a concentration of 10 uM – 50 uM can improve cell survival in neurons, while 50 uM improves survival in the other cells.
Just as cell death is induced, HIF-1a is normally increased along with VEGF mRNA expression. DMT also greatly reduces these effects.
DMT appears to exert a protective effect during hypoxia and those effects are connected to Sigma-1 receptor agonism.