Biology subjects

Nutsch, K.

Publications and source records attributed to Nutsch, K..

3 recordsLinked to original sources

bioRxiv2023

Covalent targeting as a common mechanism for inhibiting NLRP3 inflammasome assembly.

The NLRP3 inflammasome is a cytosolic protein complex important for the regulation and secretion of inflammatory cytokines including IL-1{beta} and IL-18. Aberrant overactivation of NLRP3 is implicated in numerous inflammatory disorders. However, the activation and regulation of NLRP3 inflammasome signaling remains poorly understood, limiting our ability to develop pharmacologic approaches to target this important inflammatory complex. Here, we developed and implemented a high-throughput screen to identify compounds that inhibit inflammasome assembly and activity. From this screen we identify and profile inflammasome inhibition of 20 new covalent compounds across 9 different chemical scaffolds, as well as many known inflammasome covalent inhibitors. Intriguingly, our results indicate that NLRP3 possesses numerous reactive cysteines on multiple domains whose covalent targeting blocks activation of this inflammatory complex. Specifically, focusing on compound VLX1570, which possesses multiple electrophilic moieties, we demonstrate that this compound allows covalent, intermolecular crosslinking of NLRP3 cysteines to inhibit inflammasome assembly. Our results, along with the recent identification of numerous covalent molecules that inhibit NLRP3 inflammasome activation, suggests that NLRP3 serves as a cellular electrophile sensor important for coordinating inflammatory signaling in response to redox stress. Further, our results support the potential for covalent cysteine modification of NLRP3 for regulating inflammasome activation and activity.

biochemistry↗

bioRxiv2023

Succinylation of a KEAP1 sensor lysine promotes NRF2 activation

Crosstalk between metabolism and stress-responsive signaling is essential to maintaining cellular homeostasis. One way this crosstalk is achieved is through the covalent modification of proteins by endogenous, reactive metabolites that regulate the activity of key stress-responsive transcription factors such as NRF2. Several metabolites including methylglyoxal, glyceraldehyde 3-phosphate, fumarate, and itaconate covalently modify sensor cysteines of the NRF2 regulatory protein KEAP1, resulting in stabilization of NRF2 and activation of its cytoprotective transcriptional program. Here, we employed a shRNA-based screen targeting the enzymes of central carbon metabolism to identify additional regulatory nodes bridging metabolic pathways to NRF2 activation. We found that succinic anhydride, increased by genetic depletion of the TCA cycle enzyme succinyl-CoA synthetase or by direct administration, results in N-succinylation of lysine 131 of KEAP1 to activate NRF2 transcriptional signaling. This study identifies KEAP1 as capable of sensing reactive metabolites not only by several cysteine residues but also by a conserved lysine residue, indicating its potential to sense an expanded repertoire of reactive metabolic messengers.

cell biology↗

bioRxiv2021

Metabolically Activated Proteostasis Regulators Protect Against Glutamate Toxicity by Activating NRF2

The extracellular accumulation of glutamate is a pathologic hallmark of numerous neurodegenerative diseases including ischemic stroke and Alzheimers disease. At high extracellular concentrations, glutamate causes neuronal damage by promoting oxidative stress which can lead to cellular death. This has led to significant interest in developing pharmacologic approaches to mitigate the oxidative toxicity caused by high levels of glutamate. Here, we show that the small molecule proteostasis regulator AA147 protects against glutamate-induced cell death in a neuronal-derived cell culture model by reducing intracellular levels of reactive oxygen species. While originally developed as an activator of the ATF6 arm of the unfolded protein response, we show AA147-dependent protection against glutamate toxicity is primarily mediated through activation of the NRF2-regulated oxidative stress response. We demonstrate that AA147 activates NRF2 through a mechanism involving metabolic activation to a reactive electrophile and covalent modification of KEAP1 - a mechanism analogous to that involved in AA147-dependent activation of ATF6. These results define the potential for AA147 to protect against glutamate induced oxidative toxicity and highlight the potential for metabolically-activated proteostasis regulators like AA147 to activate both protective ATF6 and NRF2 stress-responsive signaling pathways to mitigate oxidative damage associated with diverse neurologic diseases.

biochemistry↗