Cells in the human retina must rapidly adapt to constantly changing visual stimuli. This fast adaptation to varying levels and wavelengths of light helps to regulate circadian rhythms and allows for adaptation to high levels of illumination, thereby enabling the rest of the visual system to remain responsive. It has been shown that retinal microRNA (miRNA) molecules play a key role in regulating these processes. However, despite extensive research using various model organisms, light-regulated miRNAs in human retinal cells remain unknown. Here, we aim to characterize these miRNAs. We generated light-responsive human retinal organoids that express miRNA families and clusters typically found in the retina. Using an in-house developed photostimulation device, we identified a subset of light-regulated miRNAs. Importantly, we found that these miRNAs are differentially regulated by distinct wavelengths of light and have a rapid turnover, highlighting the dynamic and adaptive nature of the human retina.

• Publikační typ
• časopisecké články MeSH

Hematopoietic stem cells derived from pluripotent stem cells could be used as an alternative to bone marrow transplants. Deriving these has been a long-term goal for researchers. However, the success of these efforts has been limited with the cells produced able to engraft in the bone marrow of recipient animals only in very low numbers. There is evidence that defects in the migratory and homing capacity of the cells are due to mis-regulation of miRNA expression and are responsible for their failure to engraft. We compared the miRNA expression profile of hematopoietic progenitors derived from pluripotent stem cells to those derived from bone marrow and found that numerous miRNAs are too highly expressed in hematopoietic progenitors derived from pluripotent stem cells, and that most of these are inhibitors of epithelial-mesenchymal transition or metastasis (including miR-200b, miR-200c, miR-205, miR-148a, and miR-424). We hypothesize that the high expression of these factors, which promote an adherent phenotype, may be causing the defect in hematopoietic differentiation. However, inhibiting these miRNAs, individually or in multiplex, was insufficient to improve hematopoietic differentiation in vitro, suggesting that other miRNAs and/or genes may be involved in this process. Stem Cells 2018;36:55-64.

• MeSH
• buněčná diferenciace MeSH
• down regulace MeSH
• epitelo-mezenchymální tranzice genetika   MeSH
• hematopoetické kmenové buňky metabolismus   MeSH
• lidé MeSH
• mikro RNA genetika   MeSH
• pluripotentní kmenové buňky metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

MicroRNA (miRNAs) are short noncoding RNA molecules involved in many cellular processes and shown to play a key role in somatic cell induced reprogramming. We performed an array based screening to identify candidates that are differentially expressed between dermal skin fibroblasts (DFs) and induced pluripotent stem cells (iPSCs). We focused our investigations on miR-145 and showed that this candidate is highly expressed in DFs relative to iPSCs and significantly downregulated during reprogramming process. Inhibition of miR-145 in DFs led to the induction of "cellular plasticity" demonstrated by: (a) alteration of cell morphology associated with downregulation of mesenchymal and upregulation of epithelial markers; (b) upregulation of pluripotency-associated genes including SOX2, KLF4, C-MYC; (c) downregulation of miRNA let-7b known to inhibit reprogramming; and (iv) increased efficiency of reprogramming to iPSCs in the presence of reprogramming factors. Together, our results indicate a direct functional link between miR-145 and molecular pathways underlying reprogramming of somatic cells to iPSCs.

• MeSH
• fibroblasty cytologie   metabolismus   MeSH
• indukované pluripotentní kmenové buňky cytologie   MeSH
• lidé MeSH
• mikro RNA genetika   metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• přeprogramování buněk * genetika   MeSH
• regulace genové exprese MeSH
• reprodukovatelnost výsledků MeSH
• sekvence nukleotidů MeSH
• škára cytologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Hypoplastic left heart syndrome (HLHS) is a serious congenital cardiovascular malformation resulting in hypoplasia or atresia of the left ventricle, ascending aorta, and aortic and mitral valves. Diminished flow through the left side of the heart is clearly a key contributor to the condition, but any myocardial susceptibility component is as yet undefined. Using recent advances in the field of induced pluripotent stem cells (iPSCs), we have been able to generate an iPSC model of HLHS malformation and characterize the properties of cardiac myocytes (CMs) differentiated from these and control-iPSC lines. Differentiation of HLHS-iPSCs to cardiac lineages revealed changes in the expression of key cardiac markers and a lower ability to give rise to beating clusters when compared with control-iPSCs and human embryonic stem cells (hESCs). HLHS-iPSC-derived CMs show a lower level of myofibrillar organization, persistence of a fetal gene expression pattern, and changes in commitment to ventricular versus atrial lineages, and they display different calcium transient patterns and electrophysiological responses to caffeine and β-adrenergic antagonists when compared with hESC- and control-iPSC-derived CMs, suggesting that alternative mechanisms to release calcium from intracellular stores such as the inositol trisphosphate receptor may exist in HLHS in addition to the ryanodine receptor thought to function in control-iPSC-derived CMs. Together our findings demonstrate that CMs derived from an HLHS patient demonstrate a number of marker expression and functional differences to hESC/control iPSC-derived CMs, thus providing some evidence that cardiomyocyte-specific factors may influence the risk of HLHS.

• MeSH
• biologické modely * MeSH
• indukované pluripotentní kmenové buňky metabolismus   patologie   MeSH
• kardiomyocyty metabolismus   patologie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• novorozenec MeSH
• regulace genové exprese * MeSH
• svalové proteiny biosyntéza   MeSH
• syndrom hypoplazie levého srdce metabolismus   patologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH