Biochem/physiol Actions

Primary Targetcaspase-1/4

Reversible: yes

Cell permeable: yes

General description

An enhanced cell-permeable, non-toxic, orally available masked aspartaldehyde prodrug that is converted to its active metabolite, VRT-043198, both in vitro and in vivo via hydrolytic cleavage by esterases. The active metabolite displays anti- inflammatory and anticonvulsant properties. Binds to the active site of caspase-1 and caspase-4 with high affinity to inhibit their activity (K_i = 800 pM and 600 pM, respectively). Does not affect the activities of trypsin, cathepsin B and has much reduced effect on other caspases (K_i = 100 nM to 21.5 µM) and granzyme B (K_i = 900 nM). Recently shown to inhibit pyroptosis and prevent CD4 T-cell death by HIV-1. Also shown to block the release of lipopolysaccharide- induced IL-1β and IL-18 in human PBMC (IC₅₀ = 700 pM). Blocks Staphalococcus aureus - Cowen strain I-stimulated production of IL-1β, IL-18, and IFN-γ in human PBMCs (IC₅₀ = 870 nM and 2.8 and 5.6 µM, respectively), but does not affect the TNF-α levels (IC₅₀ >50 µM). Appears to cross the blood brain barrier to block seizure-induced IL-1β production and delay the onset and reduces the duration of seizures in rats (50 mg/kg, i.p.).Please note that the molecular weight for this compound is batch-specific due to variable water content.

The cell-permeable prodrug of the caspase-1/4-selective inhibitor VRT-43198 (K_i in nM = ﹤0.6/Caspase-4, 0.8/Caspase-1, 100/Caspase-8, 560/Caspase-6, 1,030/Caspase-9, 9,000/Granzyme B, 16,000/Caspase-7, 21,500/Caspase-3; IC₅₀ >100 µM against Cathepsin B & Trypsin). In addition to inhibiting LPS-induced IL-1β production in primary human PBMC cultures (IC₅₀ ~1 µM), VX-765 is also effective in preventing HIV infection-induced IL-1β production and pyroptosis of CD4 T cells in human lymphoid aggregate cultures (HLAC; CD4 population = 29.2% in non-infected control cultures, 8.3% vs. 30.2% in infected cultures with or without 5 µM VX-765). VX-765 is orally available in mice (Blood C_max = 0.78 µg/mL = 1.53 µM; T_max = 1.0 h; AUC_last = 2.06 µg ⋅ h/mL; 84 mg/kg, p.o.) and shown to display in vivo anti-inflammatory efficacy against LPS-induced plasma IL-1β production (ED_max = 100 mg/kg, p.o.), Oxazolone-induced delayed-type hypersensitivity (ED_max = 50 mg/kg, p.o.), collagen-induced arthritis (ED_max = 100 mg/kg, p.o.). When administered via intraperitoneal injection, VX-765 is also demonstrated to suppress the severity of seizure induction (ED_max = 50 mg/kg i.p.) among rats receiving kainic acid via intracerebroventricular injection.

Legal Information

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Other Notes

Doitsh, G., et al. 2014. Nature505, 509.Wannamaker, W., et al. 2007. J. Pharmacol. Exp. Ther.321, 509.r>Ravizza, T., et al. 2006. Epilepsia47, 1160.Stack, J.H., et al. 2005. J. Immunol.175, 2630.

Packaging

Packaged under inert gas

10 mg in Glass bottle

Reconstitution

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 1 month at -20°C.

Use only fresh DMSO for reconstitution.

Warning

Toxicity: Standard Handling (A)