ML 349

ML 349 is the active-site competitive acyl protein thioesterase 2 (APT2) inhibitor, with K_i= 0.120μM ^[1]. ML 349 is a selective, reversible inhibitor of Lysophospholipase 2 (LYPLA2), with an IC₅₀ value of 0.144μM ^[2]. ML 349 has been widely used in cell models to regulate the S-palmitoylation of proteins within the cells^[3].

In vitro, ML 349 treatment at 5μM for 16 hours can restore the membrane localization and palmitoylation of multidomain scaffolding protein Scribble (Scrib), and reduce the activation of MEK in MDCK-Snail cells^[4]. ML 349 pretreatment (20μM) in NCM460 cells for 24 hours reduced the effects of palmitic acid (PA) on the expression of APT2, p-STAT3, ZO-1, closure protein, BCL-2 and BAX, and upregulated the STAT3 palmitoylation level^[5]. Treatment with 8μM ML 349 for 72 hours led to a slight activation of AKT in NRAS mutant-SK-MEL-2 cells, without affecting the cell viability^[6].

In vivo, ML 349 treatment via intraperitoneal injection at 50mg/kg/day for 7 days prevented intestinal shortening and alleviated DSS-induced colitis in Zdhhc7-knockout mice^[7]. Injecting ML 349 (5mg/kg) into the tail vein of mice for 4 hours enhanced the palmitoylation of mitochondrial antiviral signaling protein (MAVS), increased the phosphorylation of TBK1 and IRF3, inhibited the levels of VSV-GFP and VSV titer, and elevated the mRNA levels of antiviral genes during Sendai virus (SeV) infection ^[8].

References:
[1] Won S J, Eschweiler J D, Majmudar J D, et al. Affinity-based selectivity profiling of an in-class selective competitive inhibitor of acyl protein thioesterase 2[J]. ACS Medicinal Chemistry Letters, 2017, 8(2): 215-220.
[2] Adibekian A, Martin B R, Chang J W, et al. Characterization of a selective, reversible inhibitor of lysophospholipase 2 (LYPLA2)[J]. Probe Reports from the NIH Molecular Libraries Program [Internet], 2014.
[3] Chen B, Sun Y, Niu J, et al. Protein lipidation in cell signaling and diseases: function, regulation, and therapeutic opportunities[J]. Cell chemical biology, 2018, 25(7): 817-831.
[4] Hernandez J L, Davda D, Kit M C S, et al. APT2 inhibition restores scribble localization and S-palmitoylation in snail-transformed cells[J]. Cell chemical biology, 2017, 24(1): 87-97.
[5] Wei Y, Li J, Li J, et al. Dietary long-chain fatty acids promote colitis by regulating palmitoylation of STAT3 through CD36-mediated endocytosis[J]. Cell Death & Disease, 2024, 15(1): 60.
[6] Vujic I, Sanlorenzo M, Esteve-Puig R, et al. Acyl protein thioesterase 1 and 2 (APT-1, APT-2) inhibitors palmostatin B, ML348 and ML349 have different effects on NRAS mutant melanoma cells[J]. Oncotarget, 2016, 7(6): 7297.
[7] Zhang M, Zhou L, Xu Y, et al. A STAT3 palmitoylation cycle promotes TH17 differentiation and colitis[J]. Nature, 2020, 586(7829): 434-439.
[8] Bu L, Wang H, Zhang S, et al. Targeting APT2 improves MAVS palmitoylation and antiviral innate immunity[J]. Molecular Cell, 2024, 84(18): 3513-3529. e5.

ML 349是一种活性位点竞争性酰基蛋白硫酯酶2（APT2）抑制剂，K_i值为0.12μM ^[1]。ML 349是溶血磷脂酶2（LYPLA2）的选择性可逆抑制剂，IC₅₀值为0.144μM^[2]。ML 349已被广泛应用于细胞模型中调控蛋白质的S-棕榈酰化修饰^[3]。

在体外，5μM的ML 349处理MDCK-Snail细胞16小时可恢复多结构域支架蛋白Scribble（Scrib）的膜定位和棕榈酰化，并降低MEK的激活^[4]。20μM的ML 349预处理NCM460细胞24小时能减弱棕榈酸（PA）对APT2、p-STAT3、ZO-1、闭合蛋白、BCL-2和BAX表达的影响，并上调STAT3棕榈酰化水平^[5]。8μM的ML 349处理NRAS突变的SK-MEL-2细胞72小时可轻微激活AKT，且不影响细胞活力 ^[6]。

在体内，Zdhhc7基因敲除小鼠每日腹腔注射ML 349（50mg/kg/天；持续7天）可预防肠道缩短并缓解DSS诱导的结肠炎^[7]。小鼠尾静脉注射ML 349（5mg/kg；4小时）能增强线粒体抗病毒信号蛋白（MAVS）的棕榈酰化，增加TBK1和IRF3磷酸化，抑制仙台病毒（SeV）感染期间的VSV-GFP水平和病毒滴度，并提升抗病毒基因mRNA水平^[8]。