Short Exposure to Ethanol Diminishes Caspase-1 and ASC Activation in Human HepG2 Cells In Vitro

Hörauf, Jason-Alexander; Kany, Shinwan; Janicova, Andrea; Xu, Baolin; Vrdoljak, Teodora; Sturm, Ramona; Dunay, Ildiko Rita; Martin, Lukas; Relja, Borna

doi:10.3390/ijms21093196

by Jason-Alexander Hörauf, Shinwan Kany, Andrea Janicova, Baolin Xu, Teodora Vrdoljak, Ramona Sturm, Ildiko Rita Dunay, Lukas Martin, Borna Relja

Abstract:

This paper discusses how the assembly of pro-caspase-1 and apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) in macromolecular protein complexes, inflammasomes, activates caspase-1. The present study investigates the molecular mechanisms of inflammasome activation in HepG2 cells and examines how short exposures to ethanol (EtOH) affect inflammasome activation. HepG2 cells were treated with lipopolysaccharide (LPS), ATP or nigericin (NIG) in a two-step model. After LPS priming, ATP or NIG were added. As inhibitors, sodium orthovanadate (general inhibitor of tyrosine phosphatases), AC-YVAD-CMK (caspase-1 inhibitor) or AZ10606120 (purinergic receptor P2X7R inhibitor) were applied after LPS priming. To monitor the inflammasome activation, the caspase-1 activity, ASC speck formation, reactive oxygen species (ROS) production and cell death were analyzed. To elucidate the mechanistical approach of EtOH to the inflammasome assembly, the cells were treated with EtOH either under simultaneous LPS administration or concurrently with ATP or NIG application. The co-stimulation with LPS and ATP induced a significant ASC speck formation, caspase-1 activation, cell death and ROS generation. The inhibition of the ATP-dependent purinoreceptor P2X7 decreased the caspase-1 activation, whereas sodium orthovanadate significantly induced caspase-1. Additional treatment with EtOH reversed the LPS and ATP-induced caspase-1 activation, ASC speck formation and ROS production. The ASC speck formation and caspase-1 induction require a two-step signaling with LPS and ATP in HepG2 cells. Inflammasome activation may depend on P2X7. The molecular pathway of an acute effect of EtOH on inflammasomes may involve a reduction in ROS generation, which in turn may increase the activity of tyrosine phosphatases.

Reference:

Short Exposure to Ethanol Diminishes Caspase-1 and ASC Activation in Human HepG2 Cells In Vitro (Jason-Alexander Hörauf, Shinwan Kany, Andrea Janicova, Baolin Xu, Teodora Vrdoljak, Ramona Sturm, Ildiko Rita Dunay, Lukas Martin, Borna Relja), In International journal of molecular sciences, volume 21, 2020.

Bibtex Entry:

@article{horauf_short_2020,
	title = {Short {Exposure} to {Ethanol} {Diminishes} {Caspase}-1 and {ASC} {Activation} in {Human} {HepG}2  {Cells} {In} {Vitro}},
	volume = {21},
	issn = {1422-0067 1422-0067},
	doi = {10.3390/ijms21093196},
	abstract = {This paper discusses how the assembly of pro-caspase-1 and apoptosis-associated  speck-like protein containing a caspase-recruitment domain (ASC) in macromolecular  protein complexes, inflammasomes, activates caspase-1. The present study  investigates the molecular mechanisms of inflammasome activation in HepG2 cells and  examines how short exposures to ethanol (EtOH) affect inflammasome activation. HepG2  cells were treated with lipopolysaccharide (LPS), ATP or nigericin (NIG) in a  two-step model. After LPS priming, ATP or NIG were added. As inhibitors, sodium  orthovanadate (general inhibitor of tyrosine phosphatases), AC-YVAD-CMK (caspase-1  inhibitor) or AZ10606120 (purinergic receptor P2X7R inhibitor) were applied after  LPS priming. To monitor the inflammasome activation, the caspase-1 activity, ASC  speck formation, reactive oxygen species (ROS) production and cell death were  analyzed. To elucidate the mechanistical approach of EtOH to the inflammasome  assembly, the cells were treated with EtOH either under simultaneous LPS  administration or concurrently with ATP or NIG application. The co-stimulation with  LPS and ATP induced a significant ASC speck formation, caspase-1 activation, cell  death and ROS generation. The inhibition of the ATP-dependent purinoreceptor P2X7  decreased the caspase-1 activation, whereas sodium orthovanadate significantly  induced caspase-1. Additional treatment with EtOH reversed the LPS and ATP-induced  caspase-1 activation, ASC speck formation and ROS production. The ASC speck  formation and caspase-1 induction require a two-step signaling with LPS and ATP in  HepG2 cells. Inflammasome activation may depend on P2X7. The molecular pathway of an  acute effect of EtOH on inflammasomes may involve a reduction in ROS generation,  which in turn may increase the activity of tyrosine phosphatases.},
	language = {eng},
	number = {9},
	journal = {International journal of molecular sciences},
	author = {Hörauf, Jason-Alexander and Kany, Shinwan and Janicova, Andrea and Xu, Baolin and Vrdoljak, Teodora and Sturm, Ramona and Dunay, Ildiko Rita and Martin, Lukas and Relja, Borna},
	month = apr,
	year = {2020},
	pmid = {32366053},
	pmcid = {PMC7246869},
	keywords = {Adamantane/analogs \& derivatives/pharmacology, alcohol, Amino Acid Chloromethyl Ketones/pharmacology, Aminoquinolines/pharmacology, Caspase 1/*metabolism, caspase-1, Ethanol/*pharmacology, Hep G2 Cells, Humans, in vitro, inflammasome, Inflammasomes/drug effects/metabolism, inflammation, Lipopolysaccharides/pharmacology, liver, Liver/drug effects/metabolism, Reactive Oxygen Species/metabolism, Vanadates/pharmacology}
}