Normal mesothelial cell lines newly derived from human pleural biopsy explants

Mesothelial cells are arranged as a monolayer on covering membranes that invest surfaces of body cavities like the pleura and peritoneum. Primary human mesothelial cell (HMC) cultures are needed for studying mesothelial cell homeostasis and developing disease models, such as wound healing or cancers. Remarkably, there is a paucity of useable HMC lines that are currently available that faithfully recapitulate normal in vivo phenotypic characteristics. Here, we present a strategy to recover HMC from human pleural tissue and to immortalize them for extended in vitro culturing. Human pleural membrane was harvested by minimally invasive surgical techniques. HMC were isolated using a two-step process combining explant cellular outgrowth from biopsy tissue and flow cytometry based on cell surface expression of cadherin-1 and CD71. Cell cultures were generated after lentiviral transfection with human telomerase. The new HMC cultures retain the same phenotypic traits and physiologic features as their in vivo counterparts, yet they can be adapted for short-term or long-term culture in large-scale in vitro experimentation. In particular, we generated a new HMC line harboring a germline mutation in breast cancer type-1-associated protein-1 (BAP1), a causal tumor suppressor gene, that could be instrumental to malignant mesothelioma research. Patient-specific, normal HMC may serve as novel discovery tools allowing more powerful research models of both normal physiology and disease processes. Our surgically driven approach leads to a limitless resource of novel mesothelial cell cultures.