Figure 1: AQP1 functions as a genetically encoded reporter for diffusion-weighted MRI.
From: Non-invasive imaging using reporter genes altering cellular water permeability
(a) Illustration of the impact of aquaporin expression on water diffusion across the cell membrane and the resulting decrease in diffusion-weighted signal intensity. (b) Diffusion-weighted images of CHO, U87 and Neuro 2a cell pellets expressing AQP1 or GFP, acquired using a b-value of ∼1,000 s mm−2. Scale bars, 3 mm. (c) ADC of water in CHO, U87 and Neuro 2a cells expressing AQP1 relative to GFP controls, measured at Δeff=398 ms. Transgene expression in CHO cells was induced with 1 μg ml−1 doxycycline, whereas U87 and Neuro 2a cells express AQP1 from a constitutive promoter. n=4 (U87, Neuro 2a) and 5 (CHO) biological replicates. (d) Longitudinal (T1) and (e) transverse (T2) relaxation rates in cells expressing AQP1 or GFP. n=3 (Neuro 2a, CHO) or 4 (U87) biological replicates. (f) Cell viability on AQP1 or GFP expression. n=12 (resazurin assay), 6 (ATP content), 4 (LDH release) and 3 (ethidium staining) biological replicates. Error bars±s.e.m. (g) Phase-contrast images of CHO, U87 and Neuro 2a cells expressing AQP1 or GFP. Scale bars, 10 μm.
