Analyzing mixed cell populations using aquaporin-1 as a genetically encoded reporter for Diffusion Weighted MRI and Monte Carlo Simulations

A long-standing challenge in cancer biology is to develop methodologies for measuring tumor properties noninvasively in deep tissues. This challenge is addressed by integrating Monte Carlo simulations with genetic reporters for magnetic resonance imaging(MRI). This approach revolves around a water channel called aquaporin-1(AQP1), which our lab introduced as a novel genetically encoded reporter for examining cells using MRI. AQP1-expressing cells exchange water faster than control cells, thereby showing increased water diffusion, which can be measured and imaged with diffusion-weighted MRI. The net increase in diffusion is affected by various parameters comprising cell-size, volume fraction of AQP1-labeled cells relative to unlabeled cells (the latter obstructing free diffusion), and their spatial arrangement. To use AQP1 as a noninvasive reporter for cell tracking in tissues, it is imperative to first solve the inverse problem connecting diffusion (measured with MRI) with the above-mentioned cell parameters. As a first step, we are trying to understand the relationship between diffusion changes to cell parameters in mixed cell populations of AQP1-labeled cells and unlabeled cells via live cell MRI and Monte Carlo simulations.