KT195

KT195 is a serine hydrolase inhibitor that targets ABHD6 (IC₅₀ = 10 nM) and ABHD2, with no significant activity against DAGLβ. KT195 inhibits endoplasmic reticulum calcium release and mitochondrial calcium uptake by targeting ABHD2, thereby blocking A23187 (HY-N6687) and H₂O₂-induced necrotic cell death and apoptosis. By inhibiting ABHD6 activity, KT195 significantly induces 2-AG accumulation in Neuro2A cells and reduces IL-1β secretion in lipopolysaccharide-treated macrophages. KT195 has been used as a negative control probe for DAGLβ and can be applied in studies of ABHD6 and ABHD2 in calcium signaling, lipid metabolism, neuronal function, and inflammatory^[1][2][3][4]. In Vitro:KT195 (0.2-2 μM; pretreated for 30 min) significantly inhibits 50 μMH₂O₂-induced apoptosis in MLF cells, partially inhibits 1 mM H₂O₂-induced [³H]arachidonic acid release and LDH release, and inhibits MPTP formation; in IMLF α⁻/⁻ cells, it concentration-dependently inhibits A23187-induced [³H]arachidonic acid release and LDH release (IC₅₀ ≈ 0.7 μM); but it shows no inhibitory effect on 250 nM Staurosporine (HY-15141)-induced apoptosis^[1][2].
KT195-alkyne (0.2-10 μM; 1 h) labels ABHD2 and ABHD6 in a concentration-dependent manner in the IMLF cell membrane proteome^[1].
KT195-alkyne (30 min) inhibits A23187 (HY-N6687)-induced necrotic cell death in IMLF cells, with an IC₅₀ of approximately 1.5 μM, comparable to unmodified KT195 (IC₅₀ 0.7 μM)^[1].
KT195 (10 μM) competitively blocks the binding of KT195-alkyne to ABHD2 in IMLF cells, indicating that ABHD2 is a target of KT195^[1].
KT195 (2 μM; pretreated for 30 min + co-incubated with A23187 for 30 min) still inhibits A23187-induced [³H]arachidonic acid release and LDH release in ABHD6-knockdown IMLF α⁻/⁻ cells, indicating that its anti-necrotic effect is independent of ABHD6^[2].
KT195 (0.025-2 μM) completely blocks HT-01 probe binding to ABHD6 in IMLF α⁻/⁻ cells and concentration-dependently inhibits HT-01 probe binding to ABHD6 in the IMLF α⁻/⁻ membrane proteome, with an IC₅₀ of approximately 25 nM^[2].
KT195 (pretreated for 30 min + co-incubated with A23187 for 30 min) completely blocks mitochondrial calcium uptake in IMLF α⁻/⁻ cells, but only partially reduces cytosolic calcium elevation^[2].
KT195 (2 μM; pretreated for 30 min + co-incubated with 20 μMThapsigargin for 60 min) shows no significant inhibitory effect on Thapsigargin-induced [³H]arachidonic acid release and LDH release in IMLF α⁻/⁻ cells^[2].
KT195 (2 μMor 10 μM; pretreated for 30 min then washed out) fails to inhibit [³H]arachidonic acid release and LDH release in IMLF α⁻/⁻ cells when stimulated with A23187 30 min after washout, indicating that its inhibitory effect is reversible or requires continuous target occupancy^[2].
KT195 (0.0032-10 μM; 4 h) shows potent inhibitory activity against ABHD6 in recombinant proteomes, tissue proteomes, Neuro2A cells, and PC3 cells (ex vivo IC₅₀ = 10 nM; in situ IC₅₀ ≈ 1 nM), but shows no activity against DAGLβ or other detected serine hydrolases (DAGLβ IC₅₀ > 10 μM); it does not affect SAG, 2-AG, or arachidonic acid levels in Neuro2A and PC3 cells, but induces significant accumulation of 2-AG^[3].
KT195 (2 μM; pretreated for 30 min) fully binds and inhibits ABHD6 in rat primary cortical neurons, but shows no significant inhibitory effect on NMDA (100 μM, 15 min)-induced excitotoxic cell death and mitochondrial calcium elevation^[4].
In Vivo:KT195 (0.1-10 mg/kg; i.p.; single dose; 4 h) does not inhibit DAGLβ, but inhibits ABHD6 and off-targets (CES3/CES2G/PLA2G15) in mouse peritoneal macrophages; at 5 mg/kg, it shows no effects on the aforementioned lipid mediators or TNF-α release^[3].