Ivacaftor is a potentiator of the CFTR chloride channel and is in worldwide clinical use for the chronic treatment of cystic fibrosis in patients. There is evidence that the bioavailability of ivacaftor in the body may be influenced by the multi-drug exporter P-glycoprotein. Here we have employed purified and reconstituted P-glycoprotein to study its interaction with ivacaftor as well as the ability of the drug to compete with a known transported substrate of the protein. We find that ivacaftor stimulates the ATPase activity of the purified protein and can compete with the transport of the fluorescent substrate Hoechst 33342. These findings lead us to conclude that ivacaftor is very likely an efficiently transported substrate of P-glycoprotein. Evidence for state-dependent binding of ivacaftor was obtained using a fluorescent, cysteine-reactive reporter dye. The quiescent, nucleotide-free state in the P-glycoprotein transport cycle appears to bind ivacaftor strongly.

Background Retinal regenerative therapies hold great promise for the treatment of inherited retinal degenerations (IRDs). Studies in preclinical lower mammal models of IRDs have suggested visual improvement following retinal photoreceptor precursors transplantation, but there is limited evidence on the ability of these transplants to rescue retinal damage in higher mammals. The purpose of this study was to evaluate the therapeutic potential of photoreceptor precursors derived from clinically compliant induced pluripotent stem cells (iPSCs). Methods Photoreceptor precursors were sub-retinally transplanted into non-human primates (Macaca fascicularis). The cells were transplanted both in naïve and cobalt chloride-induced retinal degeneration models who had been receiving systemic immunosuppression for one week prior to the procedure. Optical coherence tomography, fundus autofluorescence imaging, electroretinography, ex vivo histology and immunofluorescence staining were used to evaluate retinal structure, function and survival of transplanted cells. Results There were no adverse effects of iPSC-derived photoreceptor precursors on retinal structure or function in naïve NHP models, indicating good biocompatibility. In addition, photoreceptor precursors injected into cobalt chloride-induced retinal degeneration NHP models demonstrated an ability both to survive and to mature into cone photoreceptors at 3 months post-transplant. Optical coherence tomography showed restoration of retinal ellipsoid zone post-transplantation. Conclusions These findings demonstrate the safety and therapeutic potential of clinically compliant iPSC-derived photoreceptor precursors as a cell replacement source for future clinical trials.

MicroRNAs are small RNAs that are deregulated under disease conditions. This allows them to be used as biomarkers for disease diagnosis. Recently, such microRNAs are serving as non- invasive blood based biomarkers due to ease of detection, and high stability at room temperature in biofluids. In view of these advancements in biomarker research, efficient miRNA detection at the femtomolar level is important. MiRNA detection techniques to date include Northern blotting, real time PCR and microarray technology. While these are efficient techniques, they cannot detect very low miRNA levels, and have questionable specificity. This review describes nanotechnology, microfluidics and liquid phase miRNA detection techniques that are highly sensitive and specific. With some sophistication, some of these techniques can be used as point of care devices to rapidly detect low level miRNA in patient clinical samples to aid disease diagnosis and prognosis.

Objective A previous genome‐wide association study linked overexpression of an ATP‐binding cassette transporter, ABCC5, in humans with a susceptibility to developing type 2 diabetes with age. Specifically, ABCC5 gene overexpression was shown to be strongly associated with increased visceral fat mass and reduced peripheral insulin sensitivity. Currently, the role of ABCC5 in diabetes and obesity is unknown. This study reports the metabolic phenotyping of a global Abcc5 knockout mouse. Methods A global Abcc5‐/‐ mouse was generated by CRISPR/Cas9. Fat mass was determined by weekly EchoMRI and fat pads were dissected and weighed at week 18. Glucose homeostasis was ascertained by an oral glucose tolerance test, intraperitoneal glucose tolerance test, and intraperitoneal insulin tolerance test. Energy expenditure and locomotor activity were measured using PhenoMaster cages. Glucagon‐like peptide 1 (GLP‐1) levels in plasma, primary gut cell cultures, and GLUTag cells were determined by enzyme‐linked immunosorbent assay. Results Abcc5‐/‐ mice had decreased fat mass and increased plasma levels of GLP‐1, and they were more insulin sensitive and more active. Recombinant overexpression of ABCC5 protein in GLUTag cells decreased GLP‐1 release. Conclusions ABCC5 protein expression levels are inversely related to fat mass and appear to play a role in the regulation of GLP‐1 secretion from enteroendocrine cells.

No abstract