scholarly journals Embryonic hyperglycemia perturbs the development of specific retinal cell types, including photoreceptors

2021 ◽  
Author(s):  
Kayla F. Titialii-Torres ◽  
Ann C. Morris

Diabetes is linked to various long-term complications in adults, such as neuropathy, nephropathy, and diabetic retinopathy. Diabetes poses additional risks for pregnant women, because glucose passes across the placenta, and excess maternal glucose can result in diabetic embryopathy. While many studies have examined the teratogenic effects of maternal diabetes on fetal heart development, little is known about the consequences of maternal hyperglycemia on the development of the embryonic retina. To address this question, we investigated retinal development in two models of embryonic hyperglycemia in zebrafish. Strikingly, we found that hyperglycemic larvae displayed a significant reduction in photoreceptors and horizontal cells, whereas other retinal neurons were not affected. We also observed reactive gliosis and abnormal optokinetic responses in hyperglycemic larvae. Further analysis revealed delayed retinal cell differentiation in hyperglycemic embryos that coincided with increased reactive oxygen species (ROS). Our results suggest that embryonic hyperglycemia causes abnormal retinal development via altered timing of cell differentiation and ROS production, which is accompanied by visual defects. Further studies using zebrafish models of hyperglycemia will allow us to understand the molecular mechanisms underlying these effects.

2021 ◽  
Author(s):  
Kayla F. Titialii-Torres ◽  
Ann C Morris

Chronic hyperglycemia has been linked to various long-term metabolic disruptions in adults, such as neuropathy, nephropathy, and diabetic retinopathy. According to the 2020 National Diabetes Statistics Report, 10.5% of the US population has diabetes and may be susceptible to long-term complications if blood glucose is not tightly regulated. Further, in 2018, 7.6% of US pregnancies were affected by gestational diabetes, with an average of 1-14% annually. During pregnancy, glucose can pass through the placental barrier, and plays an important role in fetal development and survival. However, excess maternal glucose can also result in diabetic embryopathy. While many studies have examined the teratogenic effects of maternal diabetes on fetal heart development, little is known about the consequences of maternal hyperglycemia on the development of the embryonic retina. To address this question, we investigated retinal cell type differentiation and survival in both a genetic and nutritional model of embryonic hyperglycemia in zebrafish. Strikingly, we found that hyperglycemic larvae displayed a significant reduction in rod and cone photoreceptors and horizontal cells, whereas other retinal neurons were not affected. We also observed signs of reactive gliosis in the retinal Müller cells, as well as increased reactive oxygen species (ROS) production in hyperglycemic retinas. Hyperglycemic larvae displayed altered expression of metabolism related genes and had a slower optokinetic response than normoglycemic larvae, indicating altered visual function. Further analysis of early events in retinogenesis revealed a delay in retinal cell differentiation at 48 hpf in hyperglycemic embryos, that coincided with an increase in reactive oxygen species. Taken together, our results suggest that embryonic hyperglycemia results in abnormal retinal cell development via altered timing of retinal cell differentiation and ROS production, which is accompanied by visual defects. As the population with diabetes continues to grow, it is imperative to pinpoint the effects of embryonic hyperglycemia on retinal development. Further studies using zebrafish models of hyperglycemia will allow us to understand the molecular mechanisms underlying these effects, which could aid in the development of therapeutic strategies.


2020 ◽  
Vol 21 (22) ◽  
pp. 8484 ◽  
Author(s):  
Kritika Sharma ◽  
Tim U. Krohne ◽  
Volker Busskamp

Retinal degenerative diseases lead to irreversible blindness. Decades of research into the cellular and molecular mechanisms of retinal diseases, using either animal models or human cell-derived 2D systems, facilitated the development of several therapeutic interventions. Recently, human stem cell-derived 3D retinal organoids have been developed. These self-organizing 3D organ systems have shown to recapitulate the in vivo human retinogenesis resulting in morphological and functionally similar retinal cell types in vitro. In less than a decade, retinal organoids have assisted in modeling several retinal diseases that were rather difficult to mimic in rodent models. Retinal organoids are also considered as a photoreceptor source for cell transplantation therapies to counteract blindness. Here, we highlight the development and field’s improvements of retinal organoids and discuss their application aspects as human disease models, pharmaceutical testbeds, and cell sources for transplantations.


2020 ◽  
Vol 6 (1) ◽  
pp. 00350-2019
Author(s):  
Niki D. Ubags ◽  
Jonathan Baker ◽  
Agnes Boots ◽  
Rita Costa ◽  
Natalia El-Merhie ◽  
...  

In this review, the Basic and Translational Sciences Assembly of the European Respiratory Society (ERS) provides an overview of the 2019 ERS International Congress highlights. In particular, we discuss how the novel and very promising technology of single cell sequencing has led to the development of a comprehensive map of the human lung, the lung cell atlas, including the discovery of novel cell types and new insights into cellular trajectories in lung health and disease. Further, we summarise recent insights in the field of respiratory infections, which can aid in a better understanding of the molecular mechanisms underlying these infections in order to develop novel vaccines and improved treatment options. Novel concepts delineating the early origins of lung disease are focused on the effects of pre- and post-natal exposures on neonatal lung development and long-term lung health. Moreover, we discuss how these early life exposures can affect the lung microbiome and respiratory infections. In addition, the importance of metabolomics and mitochondrial function analysis to subphenotype chronic lung disease patients according to their metabolic program is described. Finally, basic and translational respiratory science is rapidly moving forward and this will be beneficial for an advanced molecular understanding of the mechanisms underlying a variety of lung diseases. In the long-term this will aid in the development of novel therapeutic targeting strategies in the field of respiratory medicine.


2007 ◽  
Vol 24 (3) ◽  
pp. 409-421 ◽  
Author(s):  
BHAVANI KASHYAP ◽  
LOGAN C. FREDERICKSON ◽  
DEBORAH L. STENKAMP

The exposure of the developing human embryo to ethanol results in a spectrum of disorders involving multiple organ systems, including the visual system. One common phenotype seen in humans exposed to ethanol in utero is microphthalmia. The objective of this study was to describe the effects of ethanol during retinal neurogenesis in a model organism, the zebrafish, and to pursue the potential mechanisms by which ethanol causes microphthalmia. Zebrafish embryos were exposed to 1% or 1.5% ethanol from 24 to 48 h after fertilization, a period during which the retinal neuroepithelium undergoes rapid proliferation and differentiation to form a laminated structure composed of different retinal cell types. Ethanol exposure resulted in significantly reduced eye size immediately following the treatment, and this microphthalmia persisted through larval development. This reduced eye size could not entirely be accounted for by the accompanying general delay in embryonic development. Retinal cell death was only slightly higher in ethanol-exposed embryos, although cell death in the lens was extensive in some of these embryos, and lenses were significantly reduced in size as compared to those of control embryos. The initiation of retinal neurogenesis was not affected, but the subsequent waves of cell differentiation were markedly reduced. Even cells that were likely generated after ethanol exposure—rod and cone photoreceptors and Müller glia—were delayed in their expression of cell-specific markers by at least 24 h. We conclude that ethanol exposure over the time of retinal neurogenesis resulted in persistent microphthalmia due to a combination of an overall developmental delay, lens abnormalities, and reduced retinal cell differentiation.


2019 ◽  
Author(s):  
Phuong T. Lam ◽  
Christian Gutierrez ◽  
Katia Del Rio-Tsonis ◽  
Michael L. Robinson

ABSTRACTEarly in mammalian eye development, VSX2, BRN3b, and RCVRN expression marks neural retina progenitors (NRPs), retinal ganglion cells (RGCs), and photoreceptors (PRs), respectively. The ability to create retinal organoids from human induced pluripotent stem cells (hiPSC) holds great potential for modeling both human retinal development and retinal disease. However, no methods allowing the simultaneous, real-time monitoring of multiple specific retinal cell types during development currently exist. Here, we describe a CRISPR/Cas9 gene editing strategy to generate a triple transgenic reporter hiPSC line (PGP1) that utilizes the endogenous VSX2, BRN3b, and RCVRN promoters to specifically express fluorescent proteins (Cerulean in NRPs, eGFP in RGCs and mCherry in PRs) without disrupting the function of the endogenous alleles. Retinal organoid formation from the PGP1 line demonstrated the ability of the edited cells to undergo normal retina development while exhibiting appropriate fluorescent protein expression consistent with the onset of NRPs, RGCs, and PRs. Organoids produced from the PGP1 line expressed transcripts consistent with the development of all major retinal cell types. The PGP1 line offers a powerful new tool to study retinal development, retinal reprogramming, and therapeutic drug screening.


Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 131 ◽  
Author(s):  
Roberta Russo ◽  
Selene Mallia ◽  
Francesca Zito ◽  
Nadia Lampiasi

NFATc1, which is ubiquitous in many cell types, is the master regulator of osteoclastogenesis. However, the molecular mechanisms by which NFATc1 drives its transcriptional program to produce osteoclasts from macrophages (M) remains poorly understood. We performed quantitative PCR (QPCR) arrays and bioinformatic analyses to discover new direct and indirect NFATc1 targets. The results revealed that NFATc1 significantly modified the expression of 55 genes in untransfected cells and 31 genes after NFATc1-knockdown (≥2). Among them, we focused on 19 common genes that showed changes in the PCR arrays between the two groups of cells. Gene Ontology (GO) demonstrated that genes related to cell differentiation and the development process were significantly (p > 0.05) affected by NFATc1-knockdown. Among all the genes analyzed, we focused on GATA2, which was up-regulated in NFATc1-knockdown cells, while its expression was reduced after NFATc1 rescue. Thus, we suggest GATA2 as a new target of NFATc1. Ingenuity Pathway Analysis (IPA) identified up-regulated GATA2 and the STAT family members as principal nodes involved in cell differentiation. Mechanistically, we demonstrated that STAT6 was activated in parallel with GATA2 in NFATc1-knockdown cells. We suggest an alternative pathway for macrophage differentiation in the absence of NFATc1 due to the GATA2 transcription factor.


2013 ◽  
Vol 42 (5) ◽  
pp. 2958-2975 ◽  
Author(s):  
Ajeet Pratap Singh ◽  
Trevor K. Archer

Abstract The regulatory networks of differentiation programs and the molecular mechanisms of lineage-specific gene regulation in mammalian embryos remain only partially defined. We document differential expression and temporal switching of BRG1-associated factor (BAF) subunits, core pluripotency factors and cardiac-specific genes during post-implantation development and subsequent early organogenesis. Using affinity purification of BRG1 ATPase coupled to mass spectrometry, we characterized the cardiac-enriched remodeling complexes present in E8.5 mouse embryos. The relative abundance and combinatorial assembly of the BAF subunits provides functional specificity to Switch/Sucrose NonFermentable (SWI/SNF) complexes resulting in a unique gene expression profile in the developing heart. Remarkably, the specific depletion of the BAF250a subunit demonstrated differential effects on cardiac-specific gene expression and resulted in arrhythmic contracting cardiomyocytes in vitro. Indeed, the BAF250a physically interacts and functionally cooperates with Nucleosome Remodeling and Histone Deacetylase (NURD) complex subunits to repressively regulate chromatin structure of the cardiac genes by switching open and poised chromatin marks associated with active and repressed gene expression. Finally, BAF250a expression modulates BRG1 occupancy at the loci of cardiac genes regulatory regions in P19 cell differentiation. These findings reveal specialized and novel cardiac-enriched SWI/SNF chromatin-remodeling complexes, which are required for heart formation and critical for cardiac gene expression regulation at the early stages of heart development.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philip E. Wagstaff ◽  
Anneloor L. M. A. ten Asbroek ◽  
Jacoline B. ten Brink ◽  
Nomdo M. Jansonius ◽  
Arthur A. B. Bergen

AbstractGenetically complex ocular neuropathies, such as glaucoma, are a major cause of visual impairment worldwide. There is a growing need to generate suitable human representative in vitro and in vivo models, as there is no effective treatment available once damage has occured. Retinal organoids are increasingly being used for experimental gene therapy, stem cell replacement therapy and small molecule therapy. There are multiple protocols for the development of retinal organoids available, however, one potential drawback of the current methods is that the organoids can take between 6 weeks and 12 months on average to develop and mature, depending on the specific cell type wanted. Here, we describe and characterise a protocol focused on the generation of retinal ganglion cells within an accelerated four week timeframe without any external small molecules or growth factors. Subsequent long term cultures yield fully differentiated organoids displaying all major retinal cell types. RPE, Horizontal, Amacrine and Photoreceptors cells were generated using external factors to maintain lamination.


Author(s):  
V. A. Prylutskaya ◽  
A. V. Sukalo ◽  
T. A. Derkach

It is known, that diabetes mellitus has a significant impact on the growth and development of the fetus. Hyperglycemia during pregnancy increases significantly the incidence of congenital malformations, perinatal morbidity and neonatal mortality. Over the past decades has been a steady increase in the prevalence of diabetes mellitus both in the general population and among pregnant women. In this regard, the study of the influence of diabetes mellitus in the mother on the condition of the fetus and newborn is today a relevant problem of obstetric-gynecological, neonatological and pediatric services. Hyperglycemia during pregnancy has the greatest effect on the fetal cardiovascular system. Diabetes mellitus of the mother causes an increase in the frequency of congenital heart defects in the newborn, myocardial hypertrophy, as well as various functional disorders of the cardiovascular system.This review mainly discusses the pathogenetic aspects and molecular mechanisms of the effect of hyperglycemia on the development of the fetal heart, provides an assessment of clinical, echocardiographic and some laboratory changes in the functioning of the cardiovascular system in newborns from mothers with diabetes mellitus, and also systematizes data on the relationship between maternal diabetes and the risks of cardiovascular disease in their children in the long term.


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