SP15 Role of the mTORC1 pathway in immune adaptation to genotoxic & inflammatory stress

Project Leader: Ignacio Rubio

Background and previous work
The mTORC1 pathway, with its core component mTOR and its negative upstream regulator, the tumour suppressor complex TSC1/TSC2 (tuberous sclerosis), is the principal intracellular regulatory element for energy disposal/usage, nutrient sensing and cell growth. We have disclosed an exacerbated sensitivity of TSC mutant cells to mild genotoxic stress compared to wild type cells. We found that TSC mutant cells suffer from an unusual kind of replicative stress and do not tolerate otherwise harmless doses of genotoxin (manuscript submitted).

Specific aims and working programme
We hypothesise that the failure to adapt to mild stress should compromise the plasticity and ability of immune cells (primarily monocytes/macrophages) of the TSC-/- background to adapt to infectious and genotoxic stress. Specifically, we wish to understand whether or not an impaired metabolic switch in TSC-mutant immune cells compromises adaptation to hormetic doses of inflammatory and genotoxic insults. We will employ two experimental models: 1) transgenic mice with conditional and inducible myeloid-specific knockout of TSC1 created by crossing Tsc1tm1Djk/J (carry a floxed TSC1 allele) with B6.129P2(C)-Cx3cr1tm2.1(cre/ERT2)Jung/J animals (carry a tamoxifen-inducible Cre-recombinase under the control of the myeloid-specific Cx3cr1 promoter). These animals will be subjected to various protocols of immune adaptation including genotoxic priming and endotoxin tolerance. 2) We will run analogous experiments with myeloid and lymphoid cells from TSC patients (planned 25 patients and 25 healthy controls, 2 year duration; ethic vote pending) to be enrolled in cooperation with the Children´s Hospital in Jena.