H151, a Small Molecule Inhibitor of Sting as a Novel Therapeutic in Intestinal Ischemia–reperfusion Injury

Abstract

BackgroundIntestinal ischemia–reperfusion (I/R) injury is a severe disease associated with high mortality. Stimulator of interferon genes (STING) is an intracellular protein that is activated by cytosolic DNA and is implicated in I/R injury, resulting in transcription of type I interferons (IFN-α and IFN-β) and other proinflammatory molecules. Extracellular cold-inducible RNA-binding protein (eCIRP), a damage-associated molecular pattern, induces STING activation. H151 is a small molecule inhibitor of STING that has not yet been studied as a potential therapeutic. We hypothesize that H151 reduces inflammation, tissue injury, and mortality after intestinal I/R. Methods: In vitro, RAW264.7 cells were pretreated with H151 then stimulated with recombinant murine (rm) CIRP, and IFN-β levels in the culture supernatant were measured at 24 hours after stimulation. In vivo, male C57BL/6 mice were subjected to 60-minute intestinal ischemia via superior mesenteric artery occlusion. At the time of reperfusion, mice were intraperitoneally instilled with H151 (10 mg/kg BW) or 10% Tween-80 in PBS (vehicle). Four hours after reperfusion, the small intestines, lungs, and serum were collected for analysis. Mice were monitored for 24 hours after intestinal I/R to assess survival. Results: In vitro, H151 reduced rmCIRP-induced IFN-β levels in a dose-dependent manner. In vivo, intestinal levels of pIRF3 were increased after intestinal I/R and decreased after H151 treatment. There was an increase in serum levels of tissue injury markers (lactate dehydrogenase, aspartate aminotransferase) and cytokine levels (interleukin 1β, interleukin 6) after intestinal I/R, and these levels were decreased after H151 treatment. Ischemia-reperfusion–induced intestinal and lung injury and inflammation were significantly reduced after H151 treatment, as evaluated by histopathologic assessment, measurement of cell death, chemokine expression, neutrophil infiltration, and myeloperoxidase activity. Finally, H151 improved the survival rate from 41% to 81% after intestinal I/R. Conclusions: H151, a novel STING inhibitor, attenuates the inflammatory response and reduces tissue injury and mortality in a murine model of intestinal I/R. H151 shows promise as a potential therapeutic in the treatment of this disease.

Pulsed Electric Fields Induce STING Palmitoylation and Polymerization Independently of Plasmid DNA Electrotransfer

“…STING signaling in myoblasts was inhibited by incubation with 1 µM STING palmitoylation inhibitor H-151 (Cayman Chemical, Ann Arbor, MI, USA) for 1 h, as described previously [ 38 ]. The broad-spectrum palmitoylation inhibitor 2-bromopalmitate (2-BP, Sigma-Aldrich) was tested by incubation at 25 and 50 µM for 1 h, as described previously [ 19 ].…”

cGAS-STING signaling pathway in intestinal homeostasis and diseases

“…Moreover, the absence of Sting ameliorated damage to liver and lung as well as lipid peroxidation in intestinal I/R mice model ( 179 ) ( Figure 3D ) . The STING antagonist H151 was also shown to ameliorate lung and intestinal injury, as well as systemic inflammation after intestinal I/R ( 182 ). However, it remains unclear which types of cells are responsible for the therapeutic effects of H151.…”

cGAS–STING pathway in ischemia-reperfusion injury: a potential target to improve transplantation outcomes

“…Nowadays, some preclinical studies have made progress. STING inhibitor H-515 can prevent extracellular cold-inducible RNA-binding protein, a potent DAMP, from activating STING and causing intestinal and distant organ injuries ( 59 ). Moreover, by transcriptionally upregulating cGAS expression, histone deacetylase 3 (HDAC3) activates the cGAS–STING pathway in a p65-dependent manner; tissue inflammation and injury are triggered; accordingly, HDAC3 inhibitors, such as trichostatin A and MS275, can reverse this detrimental effect ( 60 ).…”