Vitamin A and retinoid signaling in the kidneys

Bridging barriers: advances and challenges in modeling biological barriers and measuring barrier integrity in organ-on-chip systems

“…Implementation of ECIS electrodes on porous membrane cell culture inserts has recently been performed by Rajasekaran et al 237 and by Chebotarev et al 247,248 The latter studies introduced a novel, cost-effective fabrication method for integrating gold electrodes onto porous membrane in Transwell-like inserts, enabling sensitive detection of barrier formation and disruption, as well as simultaneous validation against conventional TEER and molecular permeability in the same devices. 247,248 This electrode configuration lends itself well to OOC barrier modes, facilitating direct measurements of monolayers in complex OOC systems that contain multiple cell types, as demonstrated in models of the placenta 74 and BBB 73 (Fig. 5F).…”

“…More recently, Vatine et al demonstrated in an hiPSC-derived BBB model that even low shear fluid flow can lead to upregulated expression of BBB-relevant markers like occludin and PECAM-1, with perfusion condition (0.01 dyn cm −2 ) and low level fluid shear (0.5 dyn cm −2 ) having distinct expression profiles of endothelial genes compared to each other and to static culture, as determined by principal component analysis. 72 Fluid flow is also a critical microenvironmental feature of the kidney, which filters approximately 180 litres of blood per day; 73,74 the filtration unit of the kidney, the glomerulus, is thus unsurprisingly subjected to substantial levels of shear stress, up to 20 dyn cm −2 . 75 In contrast, the intestinal barrier sees lower levels of fluid shear in vivo , with estimates in the range of 0.002–0.4 dyn cm −2 (0.0002–0.04 Pa).…”

Structure–Activity Relationships and Therapeutic Applications of Retinoids in View of Potential Benefits from Drug Repurposing Process

“…The scope of this review encompasses a comprehensive examination of retinoids and their potential for repurposing in various therapeutic contexts. This includes exploring the molecular mechanisms that govern retinoid activity, focusing on the role of retinoic acid receptors (RARs) and retinoid X receptors (RXRs) in gene regulation [16][17][18]. These receptors mediate the effects of retinoids, playing a critical role in modulating a range of biological processes.…”