Dpcd Induces Hydrocephalus Because of Partial Defects in the Inner Dynein Arms, With Abnormal Ciliary Motility

Primary ciliary dyskinesia (PCD) is a congenital disease caused by gene mutations linked to ciliary dysfunction. PCD causes different symptoms, including chronic sinusitis, infertility, situs inversus and hydrocephalus. Motile cilia on ventricular ependymal cells are a crucial factor in cerebrospinal fluid circulation, and dysfunction of these cells causes hydrocephalus. Deleted in primary ciliary dyskinesia (Dpcd) is one genetic abnormality known to cause PCD, and its knockout leads to hydrocephalus in mice. PCD occurs in Dpcd ^-/- mice because of the lack of an inner dynein arm (IDA) in the motile cilia. However, how this deficiency is associated with the motility of ventricular ependymal motile cilia in Dpcd ^-/- mice has not been demonstrated. Herein, we show that Dpcd induces partial defects in dyneins and aberrant motility in ventricular ependymal cilia. In Dpcd ^-/- mice, the ependymal cilia demonstrated decreased amplitude, abnormal waveforms and low cerebrospinal fluid flow velocity. In addition, the amount of dynein axonemal heavy chains in some IDAs decreased in the ependymal cilia. In wild-type mice, Dpcd was localised in the cytoplasm and cilia of ependymal cells. Thus, abnormal ciliary movement in Dpcd ^-/- mice is likely attributed to a defect in IDA assembly in the ependymal cilia.