DNAH14 knockout mice as a model of chronic hydrocephalus: cilia and brain-related pathology

Abstract

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by gait disturbance, cognitive impairment, and urinary incontinence. Emerging evidence suggests that ependymal ciliary dysfunction contributes to the pathophysiology of chronic hydrocephalus, including iNPH. We previously identified DNAH14 as a causative gene for familial NPH; DNAH14 is expressed in cilia and regulates ciliary motility. This study investigated the role of DNAH14 in ciliary function and hydrocephalus-related brain pathology using Dnah14 knockout ( Dnah14 −/− ) mice. Dnah14 −/− mice were generated using CRISPR/Cas9 genome editing. We evaluated ventricular morphology, ventricular communication, and behavioral function. Ciliary structure and function were assessed by electron microscopy, video microscopy, and ventricular injection of fluorescent dye. Molecular alterations associated with ciliary dysfunction were examined using microarray analysis, followed by validation with reverse transcription quantitative PCR, western blotting, and immunohistochemistry using hippocampus. Aged Dnah14 −/− mice showed significant ventricular enlargement without evidence of intraventricular obstruction compared with wild-type controls. Behavioral testing demonstrated impaired spatial memory and motor coordination, consistent with hydrocephalus-related neurological deficits. Video microscopy revealed abnormal motility of ependymal cilia, which was associated with reduced ventricular clearance efficiency. In contrast, electron microscopy showed no obvious ultrastructural abnormalities of the ependymal cilia. Microarray analysis of the hippocampus revealed downregulation of Gpr88 and Drd2 , both of which are involved in CREB-related signaling associated with synaptic transmission; these findings were validated by quantitative PCR. Immunohistochemistry and western blotting further demonstrated reduced expression of phosphorylated CREB, a downstream effector of CREB signaling. These findings demonstrate that Dnah14 is essential for normal ependymal ciliary motility and that its dysfunction contributes to chronic hydrocephalus and associated brain pathology. These findings may help elucidate how ciliary dysfunction contributes to chronic hydrocephalus and cognitive impairment in NPH and related disorders.