The main strategy for bacteria to cope with metabolic stresses is through the stringent response triggered by the accumulation of the alarmone (p)ppGpp. While metazoan genomes also encode a homologue of the (p)ppGpp hydrolase SpoT (MESH1), neither a homologue of the (p)ppGpp synthetase nor (p)ppGpp itself has been found in metazoa. Therefore, the stringent response was thought to be absent in metazoa. Unexpectedly, we found that the silencing of MESH1 in mammalian cells triggered a cellular response highly similar to the bacterial stringent response characterized by the short-term stress survival, reversible proliferation arrest as well as extensive transcriptional and metabolic reprogramming. Therefore, we investigate the in vivo function of MESH1 during disease-relevant stresses in liver and kidney. Therefore, the MESH1 plays an intriguing function in the mammalian stress adaptations. However, the bulk cell analysis of the liver and kidney limited our understanding of the relevant affected cell types and association with the enzymatic activities of MESH1. Therefore, we are seeking support to obtain a 10X Genomics Chromium controller that will enable single cell RNA-Seq to elucidate the underlying mechanisms of MESH1 during the injury of kidney and liver. The availability of such instrument will allow us to conduct reliable and reproducible RNA-Seq experiments to elucidate the biochemical basis and functional relevance of the MESH1 in the mammalian stresses response.
) MESH1 is the metazoan homologue of the bacterial (p)ppGpp hydrolase SpoT. We discovered that genetic removal of MESH1 in mammalian cells triggers a stress response that is characterized by the short-term stress survival, reversible proliferation arrest and extensive transcriptional and metabolic reprogramming. Despite the potential functional significance of MESH1 in human diseases, the biochemical basis of the MESH1-mediated stress response is not well understood, as the only known substrate for MESH1, (p)ppGpp, does not exist in mammalian cells. This proposal addresses this critical knowledge gap by unveiling novel substrates of Mesh1 and establishing their contributions to such novel forms of mammalian stress responses. A thorough understanding of the novel activities of MESH1 and their functions in mammalian cells under various stress conditions will pave the road to explore the therapeutic potential of MESH1 in various human diseases.
