Proteomic and Functional Analyses Reveal That Kallikrein 6 Enhances Communicating Hydrocephalus by Injuring Neuronal Synapses

Abstract

Communicating hydrocephalus (CH) is a common neurological disorder caused by a blockage of cerebrospinal fluid. In this study, we aimed to explore the potential molecular mechanism underlying CH development. Quantitative proteomic analysis was performed to screen the differentially expressed proteins (DEPs) between patients with and without CH. A CH rat model was verified by Hoechst staining, and the co-localization of the target protein and neuron was detected using immunofluorescence staining. Loss-of-function experiments were performed to examine the effect of KLK6 on the synapse structure. A total of 11 DEPs were identified, and kallikrein 6 (KLK6) expression was found to be significantly upregulated in patients with CH compared with that in patients without CH. The CH rat model was successfully constructed, and KLK6 was found to be co-localized with neuronal nuclei in brain tissue. The expression level of KLK6 in the CH group was higher than that in the control group. After interference of KLK6 expression, the expression levels of synapsin-1 and PSD95 in neuronal cells were increased, and the length, number, and structure of synapses were significantly improved. The transcriptome profile (PRJNA719985) after interference of KLK6 expression was obtained, and 5,681 differentially expressed genes (DEGs) were identified. The upregulated DEGs of Appl2, Nav2, and Nrn1 may be involved in the recovery of synaptic structures after interference of KLK6 expression. Collectively, KLK6 participates in the development of CH and might provide a new target for CH treatment.