scholarly journals Negative electroretinograms: genetic and acquired causes, diagnostic approaches and physiological insights

Eye ◽  
2021 ◽  
Author(s):  
Xiaofan Jiang ◽  
Omar A. Mahroo
Keyword(s):  
Clinical Approach ◽  
Physiological Basis ◽  
Wave Trough ◽  
Bright Flash ◽  
Negative Erg ◽  
Diagnostic Approaches ◽  
Current Flows ◽  
Cell Transcriptome ◽  
A Site ◽  
Single Cell Transcriptome

AbstractThe dark-adapted human electroretinogram (ERG) response to a standard bright flash includes a negative-going a-wave followed by a positive-going b-wave that crosses the baseline. An electronegative waveform (or negative ERG) results when the b-wave is selectively reduced such that the ERG fails to cross the baseline following the a-wave. In the context of a normally sized a-wave, it indicates a site of retinal dysfunction occurring after phototransduction (commonly at the photoreceptor to bipolar cell synapse). This is an important finding. In genetic disease, the pattern of ERG abnormality can point to variants in a small group of genes (frequently those associated with congenital stationary night blindness and X-linked retinoschisis, but negative ERGs can also be seen in other conditions including syndromic disease). In acquired disease, there are numerous causes, but specific features may point to melanoma-associated retinopathy (MAR). In some cases, the visual symptoms precede the diagnosis of the melanoma and so the ERG findings can initiate investigations facilitating early detection and treatment. Negative ERGs can occur in other paraneoplastic conditions, and in a range of other diseases. This review will outline the physiological basis for the negative ERG, report prevalences in the literature from different cohorts, discuss the range of causes, displaying examples of a number of ERG phenotypes, highlight features of a clinical approach to patients, and briefly discuss further insights relating to current flows shaping the a-wave trough and from single-cell transcriptome analysis.

scholarly journals Decoding the transcriptome of atherosclerotic plaque at single-cell resolution

2020 ◽  
Author(s):  
Tom Alsaigh ◽  
Doug Evans ◽  
David Frankel ◽  
Ali Torkamani
Keyword(s):  
Single Cell ◽  
Biological Processes ◽  
Main Cell ◽  
Tissue Dissociation ◽  
Inflammatory Processes ◽  
Key Drivers ◽  
Cell Transcriptome ◽  
A Site ◽  
Single Cell Transcriptome ◽  
Artery Tissue

AbstractAtherogenesis involves an interplay of inflammation, tissue remodeling and cellular transdifferentiation (CTD), making it especially difficult to precisely delineate its pathophysiology. Here we examine the single-cell transcriptome of entire atherosclerotic core (AC) plaques and patient-matched proximal adjacent (PA) portions of carotid artery tissue from patients undergoing carotid endarterectomy. We use a novel tissue dissociation strategy, single-cell RNA sequencing, and systems-biology approaches to analyze the transcriptional profiles of six main cell populations and identify key gene drivers of pathogenic biological processes in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs). Our results reveal an anatomic continuum whereby PA cells promote and respond to inflammatory processes and eventually transition through CTD into matrix-secreting cells in the AC. Inflammatory signaling in PA ECs is driven by IL6, while TNFa signaling defines inflammation in both PA ECs and VSMCs. Furthermore, we identify POSTN, SPP1 and IBSP in AC VSMCs, and ITLN1, SCX and S100A4 in AC ECs as key drivers of CTD in the atherosclerotic core. These results establish an anatomic framework for atherogenesis and suggest a site-specific strategy for disruption of disease progression.

scholarly journals Single cell transcriptome atlas of mouse mammary epithelial cells across development

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Bhupinder Pal ◽  
Yunshun Chen ◽  
Michael J. G. Milevskiy ◽  
François Vaillant ◽  
Lexie Prokopuk ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Single Cell ◽  
Developmental Stages ◽  
Mammary Epithelial Cells ◽  
Expression Profiles ◽  
Single Cells ◽  
Chromatin Accessibility ◽  
Mammary Epithelial ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome

Abstract Background Heterogeneity within the mouse mammary epithelium and potential lineage relationships have been recently explored by single-cell RNA profiling. To further understand how cellular diversity changes during mammary ontogeny, we profiled single cells from nine different developmental stages spanning late embryogenesis, early postnatal, prepuberty, adult, mid-pregnancy, late-pregnancy, and post-involution, as well as the transcriptomes of micro-dissected terminal end buds (TEBs) and subtending ducts during puberty. Methods The single cell transcriptomes of 132,599 mammary epithelial cells from 9 different developmental stages were determined on the 10x Genomics Chromium platform, and integrative analyses were performed to compare specific time points. Results The mammary rudiment at E18.5 closely aligned with the basal lineage, while prepubertal epithelial cells exhibited lineage segregation but to a less differentiated state than their adult counterparts. Comparison of micro-dissected TEBs versus ducts showed that luminal cells within TEBs harbored intermediate expression profiles. Ductal basal cells exhibited increased chromatin accessibility of luminal genes compared to their TEB counterparts suggesting that lineage-specific chromatin is established within the subtending ducts during puberty. An integrative analysis of five stages spanning the pregnancy cycle revealed distinct stage-specific profiles and the presence of cycling basal, mixed-lineage, and 'late' alveolar intermediates in pregnancy. Moreover, a number of intermediates were uncovered along the basal-luminal progenitor cell axis, suggesting a continuum of alveolar-restricted progenitor states. Conclusions This extended single cell transcriptome atlas of mouse mammary epithelial cells provides the most complete coverage for mammary epithelial cells during morphogenesis to date. Together with chromatin accessibility analysis of TEB structures, it represents a valuable framework for understanding developmental decisions within the mouse mammary gland.

Protective action of the microbial metabolite butyrate against cardiomyocyte hypertrophy

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M Umei ◽  
H Akazawa ◽  
A Saga-Kamo ◽  
H Yagi ◽  
Q Liu ◽  
...  
Keyword(s):  
Heart Failure ◽  
Short Chain Fatty Acid ◽  
Short Chain Fatty Acids ◽  
Chain Fatty Acid ◽  
G Protein Coupled Receptors ◽  
Short Chain ◽  
Cardiomyocyte Hypertrophy ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome ◽  
G Protein Coupled

Abstract Introduction Short-chain fatty acids are one of the gut microbial metabolites that may influence host physiology. We previously reported that gut dysbiosis was associated with heart failure, and that the proportions of butyrate-producing bacteria diminished prominently in the gut of patients with heart failure. Purpose We investigated the molecular mechanism of butyrate and investigated the protective mechanism against heart failure. Methods We searched for G protein-coupled receptors for short-chain fatty acids using single-cell transcriptome analysis of cardiomyocytes and non-cardiomyocytes isolated from murine hearts. In addition, we examined the effects of butyrate on endothelin-1 (ET1) or isoproterenol-induced hypertrophic responses and histone deacetylase (HDAC) activities in cultured neonatal rat cardiomyocytes. Results Single-cell transcriptome analysis and co-expression network analysis revealed that G protein-coupled receptors for short-chain fatty acid receptors were not expressed in cardiomyocytes and that Olfr78 was expressed in vascular smooth muscle cells in the heart. Treatment with butyrate inhibited ET1-induced hypertrophic growth and up-regulation of the genes such as Nppa, Acta1, and Myh7 in cultured rat neonatal cardiomyocytes. Moreover, butyrate increased the acetylation levels of histone H3, indicating that butyrate has an inhibitory effect on HDAC in cardiomyocytes. In addition, treatment with butyrate caused up-regulation of Inpp5f, encoding inositol polyphosphate-5-phosphatase f, which was associated with a significant decrease in the phosphorylation levels of Akt. These results suggest that butyrate may act as HDAC inhibitor to increase Inpp5f gene expression, leading to the activation of Akt-glycogen synthase kinase 3beta (Gsk3beta) pathway, and thereby protect against hypertrophic responses. Conclusion There was no known GPCR for short-chain fatty acid expressed in cardiomyocytes. However, butyrate suppressed cardiomyocyte hypertrophy through epigenetic modification of gene expression. Our results may uncover a potential role of the dysbiosis of intestinal microbiota in the pathogenesis of cardiac hypertrophy and failure. Funding Acknowledgement Type of funding source: None

scholarly journals Myocyte-specific enhancer factor 2c triggers transdifferentiation of adipose tissue-derived stromal cells into spontaneously beating cardiomyocyte-like cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shinichiro Takashima ◽  
Soichiro Usui ◽  
Oto Inoue ◽  
Chiaki Goten ◽  
Kosei Yamaguchi ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lentiviral Vector ◽  
Troponin T ◽  
Stromal Vascular Fraction ◽  
Cardiac Regeneration ◽  
Cardiac Lineage ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome ◽  
Culture Protocol ◽  
Enhancer Factor

AbstractCardiomyocyte regeneration is limited in adults. The adipose tissue-derived stromal vascular fraction (Ad-SVF) contains pluripotent stem cells that rarely transdifferentiate into spontaneously beating cardiomyocyte-like cells (beating CMs). However, the characteristics of beating CMs and the factors that regulate the differentiation of Ad-SVF toward the cardiac lineage are unknown. We developed a simple culture protocol under which the adult murine inguinal Ad-SVF reproducibly transdifferentiates into beating CMs without induction. The beating CMs showed the striated ventricular phenotype of cardiomyocytes and synchronised oscillation of the intracellular calcium concentration among cells on day 28 of Ad-SVF primary culture. We also identified beating CM-fated progenitors (CFPs) and performed single-cell transcriptome analysis of these CFPs. Among 491 transcription factors that were differentially expressed (≥ 1.75-fold) in CFPs and the beating CMs, myocyte-specific enhancer 2c (Mef2c) was key. Transduction of Ad-SVF cells with Mef2c using a lentiviral vector yielded CFPs and beating CMs with ~ tenfold higher cardiac troponin T expression, which was abolished by silencing of Mef2c. Thus, we identified the master gene required for transdifferentiation of Ad-SVF into beating CMs. These findings will facilitate the development of novel cardiac regeneration therapies based on gene-modified, cardiac lineage-directed Ad-SVF cells.

scholarly journals Single-Cell Transcriptome Analyses Reveal Signals to Activate Dormant Neural Stem Cells

Cell ◽  
2015 ◽  
Vol 161 (5) ◽  
pp. 1175-1186 ◽  
Author(s):  
Yuping Luo ◽  
Volkan Coskun ◽  
Aibing Liang ◽  
Juehua Yu ◽  
Liming Cheng ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Single Cell ◽  
Transcriptome Analyses ◽  
Cell Transcriptome ◽  
Single Cell Transcriptome
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