4D reconstruction of developmental trajectories using spherical harmonics

Although the full embryonic development of species such as Drosophila and zebrafish can be 3D imaged in real time, this is not true for mammalian organs, as normal organogenesis cannot be recapitulated in vitro. Currently available 3D data is therefore ex vivo images which provide only a snap shot of development at discrete moments in time. Here we propose a computer based approach to recreate the continuous evolution in time and space of developmental stages from 3D volumetric images. Our method uses the mathematical approach of spherical harmonics to re-map discrete shape data into a space in which facilitates a smooth interpolation over time. We tested our approach on mouse limb buds (from E10 to E12.5) and embryonic hearts (from 10 to 29 somites). A key advantage of the method is that the resulting 4D trajectory takes advantage of all the available data (i.e. it is not dominated by the choice of a few "ideal" images), while also being able to interpolate well through time intervals for which there is little or no data. This method not only provides a quantitative basis for validating predictive models, but it also increases our understanding of morphogenetic processes. We believe this is the first data-driven quantitative 4D description of limb morphogenesis.

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Reduced calcium storage blunts calcium signaling in Toxoplasma bradyzoites and impedes motility and egress

10.1101/2021.05.17.444531 ◽

2021 ◽

Author(s):

Yong Fu ◽

Kevin M Brown ◽

Nathaniel G Jones ◽

Silvia N J Moreno ◽

L. David Sibley

Keyword(s):

Developmental Stages ◽

Ex Vivo ◽

Acute Infection ◽

Gliding Motility ◽

Lytic Cycle ◽

Calcium Storage ◽

Calcium Atpases ◽

Dual Reporter

Toxoplasma gondii has evolved different developmental stages of tachyzoites for disseminating during acute infection and bradyzoites for establishing chronic infection. Calcium ion (Ca2+) signaling tightly regulates the lytic cycle of tachyzoites by controlling microneme secretion and motility to drive egress. However, the roles of Ca2+ signaling pathways in bradyzoites remain largely unknown. Here we show that Ca2+ signals and egress by bradyzoites in response to agonists are highly restricted. Development of dual-reporter parasites revealed dampened calcium responses and minimal microneme secretion by bradyzoites induced in vitro or harvested from infected mice and tested ex vivo. Ratiometric Ca2+ imaging demonstrated lower Ca2+ basal levels, reduced magnitude, and slower Ca2+ kinetics in bradyzoites compared with tachyzoites stimulated with agonists. Diminished responses in bradyzoites were associated with down-regulation of calcium ATPases involved in intracellular Ca2+ storage in the endoplasmic reticulum (ER) and acidocalcisome. Once liberated from cysts by trypsin digestion, bradyzoites displayed weaker gliding motility associated with Ca2+ oscillations compared with tachyzoites, although gliding motility of bradyzoites was enhanced by uptake of exogenous Ca2+. Collectively, our findings indicate that bradyzoites exhibit dampened Ca2+ signaling due to a decreased amount of stored Ca2+, limiting microneme secretion and egress, likely constituting an adaptation to their long-term intracellular niche.

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Toxoplasma bradyzoites exhibit physiological plasticity of calcium and energy stores controlling motility and egress

eLife ◽

10.7554/elife.73011 ◽

2021 ◽

Vol 10 ◽

Author(s):

Yong Fu ◽

Kevin M Brown ◽

Nathaniel G Jones ◽

Silvia NJ Moreno ◽

L David Sibley

Keyword(s):

Developmental Stages ◽

Ex Vivo ◽

Energy Levels ◽

Acute Infection ◽

Lytic Cycle ◽

Physiological Plasticity ◽

Dual Reporter ◽

Energy Stores ◽

Intracellular Ca

Toxoplasma gondii has evolved different developmental stages for disseminating during acute infection (i.e. tachyzoites) and for establishing chronic infection (i.e. bradyzoites). Calcium ion (Ca2+) signaling tightly regulates the lytic cycle of tachyzoites by controlling microneme secretion and motility to drive egress and cell invasion. However, the roles of Ca2+ signaling pathways in bradyzoites remain largely unexplored. Here we show that Ca2+ responses are highly restricted in bradyzoites and that they fail to egress in response to agonists. Development of dual-reporter parasites revealed dampened Ca2+ responses and minimal microneme secretion by bradyzoites induced in vitro or harvested from infected mice and tested ex vivo. Ratiometric Ca2+ imaging demonstrated lower Ca2+ basal levels, reduced magnitude, and slower Ca2+ kinetics in bradyzoites compared with tachyzoites stimulated with agonists. Diminished responses in bradyzoites were associated with down-regulation of Ca2+-ATPases involved in intracellular Ca2+ storage in the endoplasmic reticulum (ER) and acidocalcisomes. Once liberated from cysts by trypsin digestion, bradyzoites incubated in glucose plus Ca2+ rapidly restored their intracellular Ca2+ and ATP stores leading to enhanced gliding. Collectively, our findings indicate that intracellular bradyzoites exhibit dampened Ca2+ signaling and lower energy levels that restrict egress, and yet upon release they rapidly respond to changes in the environment to regain motility.

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The second lineage differentiation of bovine embryos fails in the absence of OCT4/POU5F1

10.1101/2021.09.06.459107 ◽

2021 ◽

Author(s):

Kilian Simmet ◽

Mayuko Kurome ◽

Valerie Zakhartchenko ◽

Horst-Dieter Reichenbach ◽

Claudia Springer ◽

...

Keyword(s):

Developmental Stages ◽

Inner Cell Mass ◽

Ex Vivo ◽

Expression Patterns ◽

Cell Mass ◽

Blastocyst Stage ◽

Bovine Embryos ◽

Vitro Fertilization ◽

Lineage Differentiation

The mammalian blastocyst undergoes two lineage segregations, i.e., formation of the trophectoderm and subsequently differentiation of the hypoblast (HB) from the inner cell mass, leaving the epiblast (EPI) the remaining pluripotent lineage. To clarify expression patterns of markers specific for these lineages in bovine embryos, we analyzed day 7, 9 and 12 blastocysts completely derived ex vivo by staining for OCT4, NANOG, SOX2 (EPI) and GATA6, SOX17 (HB) and identified genes specific for these developmental stages in a global transcriptomics approach. To study the role of OCT4, we generated OCT4-deficient (OCT4 KO) embryos via somatic cell nuclear transfer or in vitro fertilization. OCT4 KO embryos reached the expanded blastocyst stage by day 8 but lost of NANOG and SOX17 expression, while SOX2 and GATA6 were unaffected. Blastocysts transferred to recipient cows from day 6 to 9 expanded, but the OCT4 KO phenotype was not rescued by the uterine environment. Exposure of OCT4 KO embryos to exogenous FGF4 or chimeric complementation with OCT4 intact embryos did not restore NANOG or SOX17 in OCT4-deficient cells. Our data show, that OCT4 is required cell-autonomously for the maintenance of pluripotency of the EPI and differentiation of the HB in bovine embryos.

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Abstract 17290: Tead1 is Required for Cardiomyocyte Proliferation

Circulation ◽

10.1161/circ.138.suppl_1.17290 ◽

2018 ◽

Vol 138 (Suppl_1) ◽

Author(s):

Ruya Liu ◽

Rajaganapathi Jagannathan ◽

Feng Li ◽

Jeongkyung Lee ◽

Vijay K Yechoor ◽

...

Keyword(s):

Cell Cycle ◽

Developmental Stages ◽

Ex Vivo ◽

Systolic Dysfunction ◽

Hippo Pathway ◽

Perinatal Period ◽

Cyclin B1 ◽

Cardiomyocyte Proliferation ◽

M Phase

Introduction: Mammalian cardiomyocyte (CM) proliferation peaks in the embryonic and neonatal periods. TEAD1, a key transcription factor regulated by the Hippo pathway, is critical for early embryonic CM proliferation. But mid gestation lethality of Tead1 germline deletion precluded the study of its role in CMs at later developmental stages. We recently generated Tead1 floxed (Tead1 F/F ) mice which allows the study of TEAD1 function in CMs at later stages. The objective of this study was to determine requirement of TEAD1 for neonatal CM proliferation. Hypothesis: TEAD1 remains critical for CM proliferation in late embryonic and early neonatal periods through transcriptional regulation of cell cycle promoting genes. Methods and Results: We observed that TEAD1 cardiac expression peaks in the perinatal period. Using Myh6-Cre deletor mice, we knocked out Tead1 in CMs at E10.5 (referred as cKO). cKO pups were born in expected Mendelian frequency, but survived only till day of life (DOL) 9. Systolic dysfunction was evident by ECHO in DOL1 cKO pups and progressed to frank heart failure (HF) by DOL9. Histological exam showed decreased myocardial mass with increased intercellular fibrosis. Ventricles of DOL1 cKO pups demonstrated increased expression of Acta1, Nppa, and Nppb, consistent with HF but showed decreased expression of Myh7, suggesting an impairment in the typical fetal gene program activated in HF. Myocardial immunostaining showed reduction in Ki67 (G1/S/G2/M phase marker) (Fig 1) and PH3-S10 (M phase marker) positive CMs by 82% and 46% respectively in DOL1 cKO hearts, indicating significantly reduced CM proliferation. The expression of essential cell cycle proteins showed a significant decrease in the levels of G1/S regulating proteins, CDK4, CDK6, ppRB S807/811 and S/G2 and G2/M regulating proteins, pWEE1 S642 and Cyclin B1 in cKO hearts (Fig 2). Similar results in ex vivo and in vitro Tead1 knockout models in CMs using neonatal Tead1 F/F CMs and HL1 cells validated the cell autonomous regulation of CM cell cycle by TEAD1. Conclusions: TEAD1 is required for embryonic and neonatal CM proliferation and its loss at mid gestation leads to neonatal HF associated with impaired fetal gene program activation and decreased expression of cell cycle promoting genes.

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Comparative analysis of miRNA expressions in different developmental stages of Echinococcus granulosus in mono-phasic and di-phasic culture systems

Infectious Disorders - Drug Targets ◽

10.2174/1871526520999201103192518 ◽

2020 ◽

Vol 20 ◽

Author(s):

Seifollah Mortezaei ◽

Ali Afgar ◽

Balal Sadeghi ◽

Mohammad Ali Mohammadi ◽

Seyed Mohammad Mousavi ◽

...

Keyword(s):

Echinococcus Granulosus ◽

Drug Targets ◽

Developmental Stages ◽

Ex Vivo ◽

Basic Research ◽

Experimental Investigations ◽

Intermediate Hosts ◽

Germinal Layer ◽

Probable Role

Background:: The dog tapeworm, Echinococcus granulosus, is a zoonotic parasite affecting human and livestock across the globe. Basic research on the molecular biology and genetics of E. granulosus improves our understanding of the biology and potential drug targets in various developmental stages of E. granulosus in both definitive and intermediate hosts. There has been increasing interest in identification of microRNAs in parasitic organisms. The purpose of the current study was to compare the activity of a selected profile of miRNAs in different developmental stages of E. granulosus. Methods:: Different developmental stages of the parasite were obtained from ex vivo as well as in vitro cultured E. granu-losus. MicroRNAs were extracted from the ex vivo germinal layer and invaginated protoscoleces as well as the in vitro gen-erated microcysts, evaginated protoscoleces and strobilated worms. Expression of the selected miRNAs was evaluated by RT-qPCR for each stage. Results:: Four out of five miRNAs were present and active in different developmental stages of E. granulosus. A significant over-expression of miR-61 was observed in germinal layer and during the protoscolex transformation into the microcysts, however miR-10 was more expressed in the mature strobilated forms than the other stages. Let-7 and miR-3489 showed a high expression in germinal layer. Conclusion:: Differential expression of four miRNAs among different in vitro and ex vivo developmental stages of E. granu-losus was documented in the present study. Further experimental investigations are required to elucidate the probable role of the miRNAs in bi-directional differentiation of protoscoleces either into the strobilated worm or to a secondary hydatid cyst and the potential of these miRNAs as drug targets.

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Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005161x ◽

1974 ◽

Vol 32 ◽

pp. 320-321

Author(s):

J. P. Revel

Keyword(s):

Developmental Stages ◽

Three Dimensional ◽

Cell Movement ◽

Cellular Interactions ◽

Serial Sections ◽

Cell Sheets ◽

Freeze Etching ◽

Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

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Effects of the Tibetan herbal preparation PADMA 28 on blood lipids and lipid oxidisability in subjects with mild hypercholesterolaemia

VASA ◽

10.1024/0301-1526.34.1.11 ◽

2005 ◽

Vol 34 (1) ◽

pp. 11-17 ◽

Cited By ~ 12

Author(s):

Brunner-La Rocca ◽

Schindler ◽

Schlumpf ◽

Saller ◽

Suter

Keyword(s):

Endothelial Dysfunction ◽

Blood Lipids ◽

Ex Vivo ◽

Hdl Cholesterol ◽

Blood Lipid ◽

Tibetan Medicine ◽

Double Blind ◽

Intraarterial Infusion ◽

Padma 28

Background: Previous studies showed an anti-atherosclerotic effect of PADMA 28, an herbal formula based on Tibetan medicine. As the mechanisms of action are not fully understood, we investigated whether PADMA 28 may lower blood lipids and lipid oxidisability, and affect early endothelial dysfunction. Patients and methods: Sixty otherwise healthy subjects with total cholesterol ≥5.2 mmol/l and < 8.0 mmol/l were randomly assigned to placebo or PADMA 28, 3 x 2 capsules daily, for 4 weeks (double-blind). Blood lipids (total, LDL-, and HDL-cholesterol, triglycerides, Apo-lipoprotein A1 and B) and ex vivo lipid oxidisability were measured before and after treatment. In a subset of 24 subjects, endothelial function was assessed using venous occlusion plethysmography with intraarterial infusion of acetylcholine. Isolated LDL and plasma both untreated and pre-treated with PADMA 28 extract were oxidised by the radical generator AAPH. Conjugated diene formation was measured at 245 nm. Results: Blood lipids did not change during the study in both groups. In contrast to previous reports in mild hypercholesterolaemia, no endothelial dysfunction was seen and, consequently, was not influenced by therapy. Ex vivo blood lipid oxidisability was significantly reduced with PADMA 28 (area under curve: 5.29 ± 1.62 to 4.99 ± 1.46, p = 0.01), and remained unchanged in the placebo group (5.33 ± 1.88 to 5.18 ± 1.78, p > 0.1). This effect persisted one week after cessation of medication. In vitro experiments confirmed the prevention of lipid peroxidation in the presence of PADMA 28 extracts. Persistent protection was also seen for LDL isolated from PADMA 28-pretreated blood after being subjected to rigorous purification. Conclusions: This study suggests that the inhibition of blood lipid oxidisability by PADMA 28 may play a role in its anti-atherosclerotic effect.

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The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000116 ◽

2012 ◽

Vol 82 (3) ◽

pp. 228-232 ◽

Cited By ~ 7

Author(s):

Mauro Serafini ◽

Giuseppa Morabito

Keyword(s):

Antioxidant Capacity ◽

Dietary Intervention ◽

Ex Vivo ◽

The Body ◽

Dietary Polyphenols ◽

Enzymatic Antioxidant ◽

Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

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