Cl-Amidine (trifluoroacetate salt)

IC50: 5.9 μM

Cl-Amidine is a PAD4 deimination activity inhibitor.

Protein arginine deiminase 4 (PAD4) can catalyze the post-translational modification of arginine residues on histones to form citrulline, which can change gene expression. Thus, dysregulated PAD4 activity has been implicated in cancer and rheumatoid arthritis.

In vitro: Previous study found that Cl-amidine antagonized the PAD4-mediated enhancement of the the p300GBD-GRIP1 interaction dose-dependently, and it was noteworthy that Cl-amidine treatment had only a minimal reduction in the efficiency of the interaction in Cys645S-transfected cells, thereby suggesting that the inhibitory effect of Cl-amidine was not a nonspecific one but was targeted at the active PAD4 enzyme. These results demonstrated that Cl-amidine was significantly more potent than F-amidine, consistent with its improved in vitro potency [1].

In vivo: Animal study showed that Cl-amidine could improve survival in a mouse model of cecal ligation and puncture (CLP)-induced septic shock. Cl-amidine was proven to play protective roles by restoring innate immune cells in BM, decreasing BM and thymus atrophy, increasing blood monocytes and blood/liver bacteria clearance, and attenuating pro-inflammatory cytokine production in a murine lethal sepsis model [2].

Clinical trial: So far, no clinical study has been conducted.

References:
[1] Luo, Y. ,Arita, K.,Bhatia, M., et al. Inhibitors and inactivators of protein arginine deiminase 4: Functional and structural characterization. Biochemistry 45(39), 11727-11736 (2006).
[2] Zhao T, Pan B, Alam HB, Liu B, Bronson RT, Deng Q, Wu E, Li Y.  Protective effect of Cl-amidine against CLP-induced lethal septic shock in mice. Sci Rep. 2016 Nov 7;6:36696.