Using Drugs to Probe the Variability of Trans-Epithelial Airway Resistance

Abstract

BackgroundPrecision medicine aims to combat the variability of the therapeutic response to a given medicine by delivering the right medicine to the right patient. However, the application of precision medicine is predicated on a prior quantitation of the variance of the reference range of normality. Airway pathophysiology provides a good example due to a very variable first line of defence against airborne assault. Humans differ in their susceptibility to inhaled pollutants and pathogens in part due to the magnitude of trans-epithelial resistance that determines the degree of epithelial penetration to the submucosal space. This initial ‘set-point’ may drive a sentinel event in airway disease pathogenesis. Epithelia differentiated in vitro from airway biopsies are commonly used to model trans-epithelial resistance but the ‘reference range of normality’ remains problematic. We investigated the range of electrophysiological characteristics of human airway epithelia grown at air-liquid interface in vitro from healthy volunteers focusing on the inter- and intra-subject variability both at baseline and after sequential exposure to drugs modulating ion transport.Methodology/Principal FindingsBrushed nasal airway epithelial cells were differentiated at air-liquid interface generating 137 pseudostratified ciliated epithelia from 18 donors. A positively-skewed baseline range exists for trans-epithelial resistance (Min/Max: 309/2963 Ω·cm2), trans-epithelial voltage (-62.3/-1.8 mV) and calculated equivalent current (-125.0/-3.2 μA/cm2; all non-normal, P<0.001). A minority of healthy humans manifest a dramatic amiloride sensitivity to voltage and trans-epithelial resistance that is further discriminated by prior modulation of cAMP-stimulated chloride transport.Conclusions/SignificanceHealthy epithelia show log-order differences in their ion transport characteristics, likely reflective of their initial set-points of basal trans-epithelial resistance and sodium transport. Our data may guide the choice of the background set point in subjects with airway diseases and frame the reference range for the future delivery of precision airway medicine.

Deep learning predicts function of live retinal pigment epithelium from quantitative microscopy

“…The results shown in Figure 2 and Supplemental Figure 3 also highlight the robustness of the measurement across multiple microscopes or imaging configurations. Errors between different microscope measurements of the same sample were within 4.4% of the signal as compared with an average error of 31% on reference standards for VEGF ELISAs (30) and 100% for TER measurements in epithelium (31). This represents 1 to 2 orders of magnitude reduction in variability for a potential release assay for a cell-therapy product or when used in a drug screening methodology.…”

“…Additionally, the method worked on 2 different donors, not only as an end-point assay of tissue health, but also as a noninvasive tool for tracking tissue development during the long maturation period (approximately 35 days) (33). Importantly, the accuracy of the algorithms in predicting both TER and VEGFratio was close to the measurement uncertainty for both TER (31) and VEGF (30,34). The generalizability of such metrics across cell lines, regardless of donor, adds to the broad utility of this work, as here we show that even with a limited data set, strong predictive ability, regardless of donor and clone, was shown ( Figure 5).…”

BMI-1 extends proliferative potential of human bronchial epithelial cells while retaining their mucociliary differentiation capacity

“…BMI-1 TRANSDUCTION OF HBEC PROVIDES NOVEL RESPIRATORY MODELS epithelial Transwells in a 24-well ALI culture format per passage, enabling the generation of a minimum of~90 -100 Transwells from a single donor. This is significantly higher than the 10 -15 epithelial Transwells that can be generated with 1ϫ10 6 primary bronchial epithelial cells (typical quantity obtained from commercial providers) or brushing of the nasal turbinate of a single donor (29). Furthermore, subculturing of BMI-1 transformed cells, as opposed to seeding ALI cultures, would enable banking of early passage cells and the potential to generate exponentially more functional epithelia at each passage.…”

“…BMI-1 TRANSDUCTION OF HBEC PROVIDES NOVEL RESPIRATORY MODELS (29), who recently demonstrated baseline TEER values ranged from 309 to 2,963 ⍀•cm 2 in ALI cultures generated from the cells of 18 healthy donors.…”

“…Tosoni et al (29) recently demonstrated that ALI cultures generated from different healthy donors can yield epithelia with vastly different physiological properties and drug responses. The BMI-1 transduction protocol enables the generation of a large number of epithelia generated from donors with similar genetic backgrounds, or indeed from a single donor, allowing the study of disease pathophysiology in a manner that avoids the influence of genetic variability in cells from different donors.…”