Metformin promotes reversal of the epithelial-mesenchymal transition. Metformin attenuates ERK signaling by activating AMP kinase. Metformin induces hypomethylation of the E-cadherin gene promoter. Epigenetic modification of the E-cadherin promoter was observed in leukocytes from diabetic subjects. These findings provide a potential basis for decreased cancer incidence in metformin-treated subjects.

Key points During compensated hypertrophy in vivo fractional shortening (FS) remains constant until heart failure (HF) develops, when FS decreases from 70% to 39%. Compensated hypertrophy is accompanied by an increase in INa,late and a decrease in Na+,K+‐ATPase current. These changes persist as HF develops. SR Ca2+ content increases during compensated hypertrophy then decreases in HF. In healthy cells, increases in SR Ca2+ content and Ca2+ transients can be achieved by the same amount of inhibition of the Na+,K+‐ATPase as measured in the diseased cells. SERCA function remains constant during compensated hypertrophy then decreases in HF, when there is also an increase in spark frequency and spark‐mediated Ca2+ leak. We suggest an increase in INa,late and a decrease in Na+,K+‐ATPase current and function alters the balance of Ca2+ flux mediated by the Na+/Ca2+ exchange that limits early contractile impairment. Abstract We followed changes in cardiac myocyte Ca2+ and Na+ regulation from the formation of compensated hypertrophy (CH) until signs of heart failure (HF) are apparent using a trans‐aortic pressure overload (TAC) model. In this model, in vivo fractional shortening (FS) remained constant despite HW:BW ratio increasing by 39% (CH) until HF developed 150 days post‐TAC when FS decreased from 70% to 39%. Using live and fixed fluorescence imaging and electrophysiological techniques, we found an increase in INa,late from –0.34 to –0.59 A F−1 and a decrease in Na+,K+‐ATPase current from 1.09 A F−1 to 0.54 A F−1 during CH. These changes persisted as HF developed (INa,late increased to –0.82 A F−1 and Na+,K+‐ATPase current decreased to 0.51 A F−1). Sarcoplasmic reticulum (SR) Ca2+ content increased during CH then decreased in HF (from 32 to 15 μm l−1) potentially supporting the maintenance of FS in the whole heart and Ca2+ transients in single myocytes during the former stage. We showed using glycoside blockade in healthy myocytes that increases in SR Ca2+ content and Ca2+ transients can be driven by the same amount of inhibition of the Na+,K+‐ATPase as measured in the diseased cells. SERCA function remains constant in CH but decreases (τ for SERCA‐mediated Ca2+ removal changed from 6.3 to 3.0 s−1) in HF. In HF there was an increase in spark frequency and spark‐mediated Ca2+ leak. We suggest an increase in INa,late and a decrease in Na+,K+‐ATPase current and function alters the balance of Ca2+ flux mediated by the Na+/Ca2+ exchange that limits early contractile impairment.

Background Age-related macular degeneration (AMD) is a result of degeneration/damage of the retinal pigment epithelium (RPE) while retinitis pigmentosa (RP), an inherited early-onset disease, results from premature loss of photoreceptors. A promising therapeutic approach for both is the replacement of lost/damaged cells with human induced pluripotent stem cell (hiPSC)-derived retinal cells. Methods The aim of this study was to investigate the in vivo functionality of RPE and photoreceptor progenitor (PRP) cells derived from a clinical-grade hiPSC line through a unified protocol. De novo-generated RPE and PRP were characterized extensively to validate their identity, purity, and potency. Results RPE expressed tight junction proteins, showed pigmentation and ciliation, and secreted polarization-related factors vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF). PRP expressed neural retina proteins and cone and rod markers, and responded to KCl-induced polarization. Transcriptomic analysis demonstrated an increase in the expression of mature retinal tissue-specific genes coupled with concomitant downregulation of genes from undesired lineages. RPE transplantation rescued visual function in RCS rats shown via optokinetic tracking and photoreceptor rescue. PRP transplantation improved light perception in NOD.SCID-rd1 mice, and positive electroretinography signals indicated functional photoreceptor activity in the host’s outer nuclear layer. Graft survival and integration were confirmed using immunohistochemistry, and no animals showed teratoma formation or any kind of ectopic growth in the eye. Conclusions To our knowledge, this is the first demonstration of a unified, scalable, and GMP-adaptable protocol indicating strong animal efficacy and safety data with hiPSC-derived RPE and PRP cells. These findings provide robust proof-of-principle results for IND-enabling studies to test these potential regenerative cell therapies in patients.

Early lung development is a tightly orchestrated process encompassing (a) formation of definitive endoderm, (b) anteriorization of definitive endoderm, followed by (c) specification and maturation of both proximal and distal lung precursors. Several reports detailing the interaction of genes and proteins during lung development are available; however, studies reporting the role(s) of long noncoding RNAs (lncRNA) in lung morphogenesis are limited. To investigate this, we tailored a protocol for differentiation of human-induced pluripotent stem cells into distal and proximal lung progenitors to mimic in vivo lung development. The authenticity of differentiated cells was confirmed by expression of key lung markers such as FoxA2, Sox-17, Nkx2.1, Pitx2, FoxJ1, CC10, SPC, and via scanning as well as transmission electron microscopy. We employed next generation sequencing to identify lncRNAs and categorized them based on their proximity to genes essential for lung morphogenesis. In-depth bioinformatical analysis of the sequencing data enabled identification of a novel lncRNA, RP11-380D23.2, which is located upstream of PITX2 and includes a binding site for PARP1. Chromatin immunoprecipitation and other relevant studies revealed that PARP1 is a repressor for PITX2. Whole genome microarray analysis of RP11-380D23.2/PITX2 knockdown populations of progenitors demonstrated enrichment in proximal progenitors and indicated altered distal-proximal patterning. Dysregulation of WNT effectors in both knockdowns highlighted direct modulation of PITX2 by RP11-380D23.2. Most of these results were validated in four independent hiPSC lines (including a patient-specific CFTR mutant line). Taken together, these findings offer a mechanistic explanation underpinning the role of RP11-380D23.2 during lung morphogenesis via WNT signaling. Stem Cells 2018;36:218-229.