Modulation of brain cation-Cl− cotransport via the SPAK kinase inhibitor ZT-1a

Abstract

The SLC12A cation-Cl − cotransporters (CCC), including NKCC1 and the KCCs, are important determinants of brain ionic homeostasis. SPAK kinase (STK39) is the CCC master regulator, which stimulates NKCC1 ionic influx and inhibits KCC-mediated efflux via phosphorylation at conserved, shared motifs. Upregulation of SPAK-dependent CCC phosphorylation has been implicated in several neurological diseases. Using a scaffold-hybrid strategy, we develop a novel potent and selective SPAK inhibitor, 5-chloro-N-(5-chloro-4-((4-chlorophenyl)(cyano) methyl)-2-methylphenyl)-2-hydroxybenzamide ("ZT-1a"). ZT-1a inhibits NKCC1 and stimulates KCCs by decreasing their SPAK-dependent phosphorylation. Intracerebroventricular delivery of ZT-1a decreases inflammation-induced CCC phosphorylation in the choroid plexus and reduces cerebrospinal fluid (CSF) hypersecretion in a model of post-hemorrhagic hydrocephalus. Systemically administered ZT-1a reduces ischemia-induced CCC phosphorylation, attenuates cerebral edema, protects against brain damage, and improves outcomes in a model of stroke. These results suggest ZT-1a or related compounds may be effective CCC modulators with therapeutic potential for brain disorders associated with impaired ionic homeostasis.

Transient enlargement of brain ventricles during relapsing-remitting multiple sclerosis and experimental autoimmune encephalomyelitis

“…This could be reversed with drugs targeting these signaling pathways, leading to protection from the experimentally induced ventricle enlargement (52). Another group used a small molecule inhibitor of SPAK-dependent phosphorylation of ion transporters and were able to reverse CSF hypersecretion in experimental ischemic stroke (53). These studies demonstrate how inflammatory processes at the choroid plexus can result in expansion of the cerebral ventricles due to CSF overproduction in PHH and have implications beyond hydrocephalus and stroke to other acute and chronic inflammatory diseases (54).…”

The Therapeutic Potential of Neuronal K-Cl Co-Transporter KCC2 in Huntington’s Disease and Its Comorbidities

“…To start with, dysfunctions in GABAergic inhibitory neural transmission happen in neurological disorders including HD [2,59,72]. KCC2 is a key moderator of inhibitory GABAergic inputs in normal/healthy adult neurons, as its Cl − extruding activity facilitates the hyperpolarizing reversal potential for GABA A R Cl − currents and its disruption promotes HD-associated symptoms [2,29,59,76,87]. Certainly, KCC2 interacts with HTT and is downregulated in HD, which contributed to GABAergic excitation and memory deficits in the R6/2 mouse HD model [2,59].…”

Role of the Cation-chloride-cotransporters in Cardiovascular Disease

“…Through the use of in vivo SPAK mouse model, we then found a role for SPAK or OSR1 as a bridge to facilitate the signalling cascade between WNKs and CCCs [109]. Furthermore, we have developed a novel SPAK binding inhibitor, termed ZT-1a, which specifically blocks the WNK-SPAK/OSR1-CCC signalling pathway, subsequently reducing the NKCC1 and KCCs phosphorylation in cultured cells, and in vivo mouse and rat tissues [110]. This is promising for the treatment of cardiovascular disease as ZT-1a may interfere with the SPAK regulation of [Cl -]i homeostasis via NKCC1 and KCCs in cardiac cells.…”