Immortalization and functional characterization of rat arachnoid cell lines

Modeling the behavior of mammalian arachnoid cells is critical to understand hydrocephalus and other brain disorders involving abnormal flow of cerebrospinal fluid, yet relatively little is known about the physiology of arachnoid cells due to lack of a robust three-dimensional model system. Explanted primary cultures have been the only option to study transport across arachnoid cell membranes, but practical limitations of primary culture include slow growth, early senescence, and poor reproducibility. The purpose of this study was to create immortalized rat arachnoid cell lines to permit in vitro study of arachnoid granulations and properties of cerebrospinal fluid (CSF) flow. We established and partially characterized two immortalized cell lines generated from primary rat arachnoid cells, using retroviral gene transfer of SV40 large T antigen (SV40 LTAg) either with or without human telomerase (hTERT). The established cell lines stably express either SV40 LTAg alone, or SV40 LTAg and hTERT, and demonstrate high proliferative rate, contact inhibition at confluence, and stable expression of protein markers characteristic of native arachnoid cells over more than 160 passages.