Preclinical Development of the Na-K-2Cl Co-transporter-1 (NKCC1) Inhibitor ARN23746 for the Treatment of Neurodevelopmental Disorders

Abstract

Alterations in the expression of the Cl − importer Na-K-2Cl co-transporter-1 (NKCC1) and the exporter K-Cl cotransporter 2 (KCC2) lead to impaired intracellular chloride concentration in neurons and imbalanced excitation/inhibition in the brain. These alterations have been observed in several neurological disorders (e.g., Down syndrome and autism). Recently, we have reported the discovery of the selective NKCC1 inhibitor "compound ARN23746" for the treatment of Down syndrome and autism in mouse models. Here, we report on an extensive preclinical characterization of ARN23746 toward its development as a clinical candidate. ARN23746 shows an overall excellent metabolism profile and good brain penetration. Moreover, ARN23746 is effective in rescuing cognitive impairment in Down syndrome mice upon per os administration, in line with oral treatment of neurodevelopmental disorders. Notably, ARN23746 does not present signs of toxicity or diuresis even if administered up to 50 times the effective dose. These results further support ARN23746 as a solid candidate for clinical trial-enabling studies.

Cation Chloride Cotransporter NKCC1 Operates through a Rocking-Bundle Mechanism

“…These TM residues, all located at the outer vestibule (Figure A), were selected because of their involvement in the dynamic interaction network highlighted by our MD simulations for NKCC1 conformational transitions. Next, we performed in vitro Cl – influx assay − measurements on HEK293 cells transfected with one of the four mouse NKCC1 mutants, at the time.…”

The role of elasticity on adhesion and clustering of neurons on soft surfaces

“…In this study, we employed established techniques for collecting and culturing primary hippocampal neurons 73 . Although this approach might yield a mix of neurons and glial cells, previous research indicates that the presence of glial cells is significantly less critical than that of neurons 39 , 74 , 75 . To demonstrate that glial cells constitute a minor fraction of the total cell population on the substrate surfaces, we conducted further experiments (Supplementary Note 11 ).…”

Heterogeneous subpopulations of GABAAR-responding neurons coexist across neuronal network scales and developmental stages in health and disease

“…Thus, neurons derived from patient iPSC lines could be used for patient stratification in future clinical trials for DS and possibly for many other brain disorders characterized by impaired chloride homeostasis. 13 This would be very interesting also considering the increasing interest of the academia and pharma companies in drug discovery programs aiming at finding new compounds able to selectively inhibit NKCC1, 86 , 87 , 88 activate KCC2, 89 , 90 , 91 , 92 or acting downstream of their signaling pathways. 22 , 93 …”