Hi everyone,
Some papers showed LPS (100-200ng/ml) can induce apoptosis of THP1 monocytes (proved by TUNEL, Caspae 3/7 activity and LDH release). But I couldn't reproduce same results even use LPS up to 1ug/ml and I can not see any increase of TUNEL positive cells, caspase activity and LDH release comparing to NT. Cell death only happened in my hands after differentiation of THP1 into macrophage with PMA. Also, if I treat THP1 monocytes with LPS+IFNgamma, cell number actually goes down and LDH release goes up. But I still couldn't see any TUNEL positive cells and caspase activation.
So I want to know if anybody induce THP1 monocytes apoptosis with LPS alone and tips for this induction?
In addition, I think LPS+IFNgamma inducing THP1 monocytes death might be caused by necrosis or some other cell death types since we couldn't see increase of TUNEL and caspase 3/7 activity. Anybody could give me some suggestions how to identify the cell death type in THP1 monocyte stimulated with LPS+IFNgamma?
Thanks a lot.
Undifferentiated THP-1 cells, when treated with LPS, induce the expression of pro-inflammatory genes. Further, the treatment does not result in appreciable cell death. Treatment of cells with PMA, followed by treatment with LPS results in spentaneous cell death by pyroptosis. This cell death is measurable. However, the presence of pathogen-associated molecular patterns (e.g., ATP or cellular DNA) results in significant cell death by pyroptosis due to activation of inflammasome(s).
Dear Divaker
Thanks for your explanation. I just read the paper about induction of THP-1 apoptosis with LPS alone and wondering why don't I can reproduce it.
Thanks!
Shujun, is the paper you read the Fernandes-Alnemri et al. paper about the discovery of the Pyroptosome? If so, it's important to note that they use a crude preparation of LPS, which possibly contains other components of bacteria in addition to LPS. Ultrapure LPS that is free from other bacterial components may not result in pyroptosis.
Hi Jordan
It's not the paper you mentioned and is published this year on CDD. The LPS they used is from E. coli 026:B6 (Sigma-Aldrich) and no cat no. was provided. But I think it should be pure LPS after checking on sigma website.
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