Regulation of TRPV4 Function and Barrier Integrity of Human Choroid Plexus Epithelial Cells by Hemoglobin or LPS

Hydrocephalus is a debilitating neurological condition characterized by abnormal cerebrospinal fluid (CSF) accumulation, frequently linked to inflammation and barrier dysfunction in the choroid plexus epithelium (CPE) as Blood-CSF-Barrier (BCSFB). Prior studies in a genetic rat model demonstrated that inhibiting transient receptor potential vanilloid 4 (TRPV4), an osmo-, shear-, temperature-, pressure-, and inflammation-sensitive non-selective cation channel expressed in the CPE, can ameliorate ventriculomegaly, but the extent to which inflammatory mediators directly modulate TRPV4 activity in human CPE cells remains unknown. Lysophosphatidic acid (LPS) and hemoglobin are key drivers of inflammation in post-infectious and post-hemorrhagic hydrocephalus respectively. We hypothesize that these molecules could modulate TRPV4 channel activity and disrupt CPE barrier function, contributing to CSF dysregulation. To investigate this, we employed the human choroid plexus papilloma cell line (HIBCPP), a well-characterized in vitro model that closely resembles the morphology, transporter expression, and physiological behavior of native CPE cells. HIBCPP cells were treated with physiologically relevant concentrations of LPS (10 ng/mL) or bovine hemoglobin (1.4 mg/mL) applied to the apical, basolateral, or both sides of the epithelium, to simulate the inflammatory conditions. Using Ussing-style electrophysiology, we quantified transepithelial conductance (a measure of transepithelial permeability) and transepithelial ion flux before and following the activation of TRPV4 by using the selective agonist GSK1016790A. Our findings suggest that LPS treatment modifies the ion transport across the CPE both within a short time (10 minutes) and long-term treatment (24 hours), with the most robust effects following the basolateral application. This included a significant increase in transepithelial conductance after 24 hours. Hemoglobin treatment for 10 minutes did not cause significant changes in ion flux or conductance. Therefore, the data indicate that selective inflammatory mediators may modulate both TRPV4 activity and barrier function in the CPE and suggest a potential mechanism contributing to the dysregulation of CSF and identify TRPV4 as a possible therapeutic target to reduce the inflammatory-driven changes in hydrocephalus. As a result of this observation, we further speculate that exposure to inflammatory mediators could induce production of cytokines by the CPE, thus leading to propagation of inflammatory signals into distant parts of the brain and contributing to neuroinflammation and CSF dysregulation in hydrocephalus. This study was supported by DoD Congressionally Directed Medical Research Program Grants #HT94252310296 and #HT94252310401 (BBY) This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.