Characterization of a novel subset of cardiac cells and their progenitors in the Drosophila embryo

Development ◽  
2000 ◽  
Vol 127 (22) ◽  
pp. 4959-4969 ◽  
Author(s):  
E.J. Ward ◽  
J.B. Skeath

The Drosophila heart is a simple organ composed of two major cell types: cardioblasts, which form the simple contractile tube of the heart, and pericardial cells, which flank the cardioblasts. A complete understanding of Drosophila heart development requires the identification of all cell types that comprise the heart and the elucidation of the cellular and genetic mechanisms that regulate the development of these cells. Here, we report the identification of a new population of heart cells: the Odd skipped-positive pericardial cells (Odd-pericardial cells). We have used descriptive, lineage tracing and genetic assays to clarify the cellular and genetic mechanisms that control the development of Odd-pericardial cells. Odd skipped marks a population of four pericardial cells per hemisegment that are distinct from previously identified heart cells. We demonstrate that within a hemisegment, Odd-pericardial cells develop from three heart progenitors and that these heart progenitors arise in multiple anteroposterior locations within the dorsal mesoderm. Two of these progenitors divide asymmetrically such that each produces a two-cell mixed-lineage clone of one Odd-pericardial cell and one cardioblast. The third progenitor divides symmetrically to produce two Odd-pericardial cells. All remaining cardioblasts in a hemisegment arise from two cardioblast progenitors each of which produces two cardioblasts. Furthermore, we demonstrate that numb and sanpodo mediate the asymmetric divisions of the two mixed-lineage heart progenitors noted above.

2020 ◽  
Author(s):  
Wei Feng ◽  
Hannah Schriever ◽  
Shan Jiang ◽  
Abha Bais ◽  
Dennis Kostka ◽  
...  

AbstractHeart organoids have the potential to generate primary heart-like anatomical structures and hold great promise as in vitro models for cardiac disease. However, their properties have not yet been carefully studied, which hinders a wider spread application. Here we report the development of differentiation systems for ventricular and atrial heart organoids, enabling the study of heart disease with chamber defects. We show that our systems generate organoids comprising of major cardiac cell types, and we used single cell RNA sequencing together with sample multiplexing to characterize the cells we generate. To that end, we also developed a machine learning label transfer approach lever-aging cell type, chamber, and laterality annotations available for primary human fetal heart cells. We then used this model to analyze organoid cells from an isogeneic line carrying an Ebstein’s anomaly associated genetic variant, and we successfully recapitulated the disease’s atrialized ventricular defects. In summary, we have established a workflow integrating heart organoids and computational analysis to model heart development in normal and disease states.


Development ◽  
1999 ◽  
Vol 126 (14) ◽  
pp. 3241-3251 ◽  
Author(s):  
M.T. Su ◽  
M. Fujioka ◽  
T. Goto ◽  
R. Bodmer

A series of inductive signals are necessary to subdivide the mesoderm in order to allow the formation of the progenitor cells of the heart. Mesoderm-endogenous transcription factors, such as those encoded by twist and tinman, seem to cooperate with these signals to confer correct context and competence for a cardiac cell fate. Additional factors are likely to be required for the appropriate specification of individual cell types within the forming heart. Similar to tinman, the zinc finger- and homeobox-containing gene, zfh-1, is expressed in the early mesoderm and later in the forming heart, suggesting a possible role in heart development. Here, we show that zfh-1 is specifically required for formation of the even-skipped (eve)-expressing subset of pericardial cells (EPCs), without affecting the formation of their siblings, the founders of a dorsal body wall muscle (DA1). In addition to zfh-1, mesodermal eve itself appears to be needed for correct EPC differentiation, possibly as a direct target of zfh-1. Epistasis experiments show that zfh-1 specifies EPC development independently of numb, the lineage gene that controls DA1 founder versus EPC cell fate. We discuss the combinatorial control mechanisms that specify the EPC cell fate in a spatially precise pattern within the embryo.


2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi7-vi7
Author(s):  
Kyle Smith ◽  
Laure Bihannic ◽  
Brian Gudenas ◽  
Qingsong Gao ◽  
Parthiv Haldipur ◽  
...  

Abstract Understanding the interplay between normal development and tumorigenesis, including the identification and characterization of lineage-specific origins of MB, is a fundamental challenge in the field. Recent studies have highlighted novel associations between biologically distinct MB subgroups and diverse murine cerebellar lineages via cross-species single-cell transcriptomics. Specifically, Group 4-MB correlated with the unipolar brush cell lineage and Group 3-MB resembled Nestin+ stem cells of the early cerebellum. However, these analyses were hampered by low resolution due to the sparsity of pertinent cerebellar cell types and the cross-species nature of the approach. Herein, we profoundly expand the depth of these rare developmental populations in the murine cerebellum using a combination of lineage tracing and integrative multi-omics. Isolation and enrichment of spatially and temporally unique developmental trajectories of key rhombic lip-derived glutamatergic lineages provided an enhanced reference for mapping MB subgroups based on molecular overlap, especially for poorly defined Group 3- and Group 4-MB. Further comparisons to a novel single-cell atlas of the human fetal cerebellum, companioned with laser-capture microdissected transcriptional and epigenetic datasets, reinforced developmental insights extracted from the mouse. Characterization of compartment-specific transcriptional programs and co-expression networks identified in the human upper rhombic lip implicated convergent cellular correlates of Group 3- and Group 4-MB, suggestive of a common developmental link. Together, our results strongly implicate developmental lineages of the upper rhombic lip as the probable origins of poorly defined Group 3- and Group 4-MB. These important findings will shape future efforts to accurately model the biological heterogeneity underlying these subgroups and provide unprecedented opportunities to explore their cellular and mechanistic basis.


Development ◽  
2002 ◽  
Vol 129 (13) ◽  
pp. 3241-3253 ◽  
Author(s):  
Aymeric Chartier ◽  
Stéphane Zaffran ◽  
Martine Astier ◽  
Michel Sémériva ◽  
Danielle Gratecos

The steps that lead to the formation of a single primitive heart tube are highly conserved in vertebrate and invertebrate embryos. Concerted migration of the two lateral cardiogenic regions of the mesoderm and endoderm (or ectoderm in invertebrates) is required for their fusion at the midline of the embryo. Morphogenetic signals are involved in this process and the extracellular matrix has been proposed to serve as a link between the two layers of cells.Pericardin (Prc), a novel Drosophila extracellular matrix protein is a good candidate to participate in heart tube formation. The protein has the hallmarks of a type IV collagen α-chain and is mainly expressed in the pericardial cells at the onset of dorsal closure. As dorsal closure progresses, Pericardin expression becomes concentrated at the basal surface of the cardioblasts and around the pericardial cells, in close proximity to the dorsal ectoderm. Pericardin is absent from the lumen of the dorsal vessel.Genetic evidence suggests that Prc promotes the proper migration and alignment of heart cells. Df(3)vin6 embryos, as well as embryos in which prc has been silenced via RNAi, exhibit similar and significant defects in the formation of the heart epithelium. In these embryos, the heart epithelium appears disorganized during its migration to the dorsal midline. By the end of embryonic development, cardial and pericardial cells are misaligned such that small clusters of both cell types appear in the heart; these clusters of cells are associated with holes in the walls of the heart. A prc transgene can partially rescue each of these phenotypes, suggesting that prc regulates these events. Our results support, for the first time, the function of a collagen-like protein in the coordinated migration of dorsal ectoderm and heart cells.


2018 ◽  
Author(s):  
Emily Abrash ◽  
M Ximena Anleu Gil ◽  
Juliana L Matos ◽  
Dominique C Bergmann

AbstractAll multicellular organisms must properly pattern cell types to generate functional tissues and organs. The organized and predictable cell lineages of the Brachypodium leaf enabled us to characterize the role of the MAPK kinase kinase gene BdYODA1 in regulating asymmetric cell divisions. We find that YODA genes promote normal stomatal spacing patterns in both Arabidopsis and Brachypodium, despite species-specific differences in those patterns. Using lineage tracing and cell fate markers, we show that, unexpectedly, patterning defects in bdyoda1 mutants do not arise from faulty physical asymmetry in cell divisions but rather from improper enforcement of alternative cellular fates after division. These cross-species comparisons allow us to refine our interpretations of MAPK activities during plant asymmetric cell divisions.Summary StatementAnalysis of Brachypodium leaf epidermis development reveals that the MAPKKK, BdYODA1, regulates asymmetric divisions by enforcing resultant cell fates rather than driving initial physical asymmetries.


2017 ◽  
Vol 49 (7) ◽  
pp. 368-384 ◽  
Author(s):  
S. A. Booth ◽  
F. J. Charchar

Telomeres are repetitive nucleoprotein structures at chromosome ends, and a decrease in the number of these repeats, known as a reduction in telomere length (TL), triggers cellular senescence and apoptosis. Heart disease, the worldwide leading cause of death, often results from the loss of cardiac cells, which could be explained by decreases in TL. Due to the cell-specific regulation of TL, this review focuses on studies that have measured telomeres in heart cells and critically assesses the relationship between cardiac TL and heart function. There are several lines of evidence that have identified rapid changes in cardiac TL during the onset and progression of heart disease as well as at critical stages of development. There are also many factors, such as the loss of telomeric proteins, oxidative stress, and hypoxia, that decrease cardiac TL and heart function. In contrast, antioxidants, calorie restriction, and exercise can prevent both cardiac telomere attrition and the progression of heart disease. TL in the heart is also indicative of proliferative potential and could facilitate the identification of cells suitable for cardiac rejuvenation. Although these findings highlight the involvement of TL in heart function, there are important questions regarding the validity of animal models, as well as several confounding factors, that need to be considered when interpreting results and planning future research. With these in mind, elucidating the telomeric mechanisms involved in heart development and the transition to disease holds promise to prevent cardiac dysfunction and potentiate regeneration after injury.


Author(s):  
A. LeFurgey ◽  
L.A. Hawkey ◽  
M.C. Carney ◽  
P. Ingram ◽  
M. Lieberman

Cultured embryonic chick heart cells have been utilized as a model system for characterization of various membrane transport mechanisms. One advantage of this system is that the cells may be grown with differing geometries to minimize diffusion limitations and to optimize the growth configuration for particular techniques, such as ion-selective microelectrode measurements, fluorescent dye indicators, patch clamp, etc. A spontaneously contracting strand of cells embedded in a collagen matrix has recently been developed for measurements of cytoplasmic free ions by nuclear magnetic resonance (NMR) spectroscopy. These same strands, which provide the large numbers of cells needed for NMR, can be subdivided into small fragments ideal for cryopreservation prior to electron probe X-ray microanalysis (EPXMA). The aims in this study were to characterize the ultrastructure of cardiac cells within the strand, to demonstrate the quality of preservation obtainable by quick freezing methods, and to quantitatively map with EPXMA the distribution of physiologically relevant elements in thin, freeze-dried cryosections of the cells.Cells were isolated by serial trypsinization of 11-day old embryonic chick hearts. Strands of cells approximately 100 cm in length and 0.2 mm in diameter were obtained by extrusion of a cell-collagen mixture through polyethylene tubing into media within a culture dish. Three to five millimeter segments of 1-day old strands which contracted spontaneously were preserved by rapid immersion in liquid nitrogen-cooled liquid propane at 〜-185°C and stored in liquid nitrogen prior to being (a) cryosectioned for subsequent EPXMA or (b) freeze-substituted for conventional transmission electron microscopy (CTEM). Segments of strands were also chemically preserved in 2.5% glutaraldehyde in 0.1 M sodium cacodylate and processed as above for comparative CTEM. Cryosections of the frozen strands were cut at <-140°C with a dry glass knife and placed directly onto pre-cooled, carbon-coated, 200 mesh, fine bar nickel grids with a precooled implement. The grids were transferred to a liquid nitrogen cooled copper well for freeze drying at 10‒3 Torr over 24 to 48 hours. Prior to EPXMA, the grids were coated with 〜1OOÅ carbon.


Author(s):  
W.G. Wier

A fundamentally new understanding of cardiac excitation-contraction (E-C) coupling is being developed from recent experimental work using confocal microscopy of single isolated heart cells. In particular, the transient change in intracellular free calcium ion concentration ([Ca2+]i transient) that activates muscle contraction is now viewed as resulting from the spatial and temporal summation of small (∼ 8 μm3), subcellular, stereotyped ‘local [Ca2+]i-transients' or, as they have been called, ‘calcium sparks'. This new understanding may be called ‘local control of E-C coupling'. The relevance to normal heart cell function of ‘local control, theory and the recent confocal data on spontaneous Ca2+ ‘sparks', and on electrically evoked local [Ca2+]i-transients has been unknown however, because the previous studies were all conducted on slack, internally perfused, single, enzymatically dissociated cardiac cells, at room temperature, usually with Cs+ replacing K+, and often in the presence of Ca2-channel blockers. The present work was undertaken to establish whether or not the concepts derived from these studies are in fact relevant to normal cardiac tissue under physiological conditions, by attempting to record local [Ca2+]i-transients, sparks (and Ca2+ waves) in intact, multi-cellular cardiac tissue.


Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 640
Author(s):  
Natalia R. Moyetta ◽  
Fabián O. Ramos ◽  
Jimena Leyria ◽  
Lilián E. Canavoso ◽  
Leonardo L. Fruttero

Hemocytes, the cells present in the hemolymph of insects and other invertebrates, perform several physiological functions, including innate immunity. The current classification of hemocyte types is based mostly on morphological features; however, divergences have emerged among specialists in triatomines, the insect vectors of Chagas’ disease (Hemiptera: Reduviidae). Here, we have combined technical approaches in order to characterize the hemocytes from fifth instar nymphs of the triatomine Dipetalogaster maxima. Moreover, in this work we describe, for the first time, the ultrastructural features of D. maxima hemocytes. Using phase contrast microscopy of fresh preparations, five hemocyte populations were identified and further characterized by immunofluorescence, flow cytometry and transmission electron microscopy. The plasmatocytes and the granulocytes were the most abundant cell types, although prohemocytes, adipohemocytes and oenocytes were also found. This work sheds light on a controversial aspect of triatomine cell biology and physiology setting the basis for future in-depth studies directed to address hemocyte classification using non-microscopy-based markers.


Sign in / Sign up

Export Citation Format

Share Document