| 1. |
- Ali, Zaheer, et al.
(författare)
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Synchronized tissue-scale vasculogenesis and ubiquitous lateral sprouting underlie the unique architecture of the choriocapillaris
- 2020
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Ingår i: Developmental Biology. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0012-1606 .- 1095-564X. ; 457:2, s. 206-214
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Tidskriftsartikel (refereegranskat)abstract
- The choriocapillaris is an exceptionally high density, two-dimensional, sheet-like capillary network, characterized by the highest exchange rate of nutrients for waste products per area in the organism. These unique morphological and physiological features are critical for supporting the extreme metabolic requirements of the outer retina needed for vision. The developmental mechanisms and processes responsible for generating this unique vascular network remain, however, poorly understood. Here we take advantage of the zebrafish as a model organism for gaining novel insights into the cellular dynamics and molecular signaling mechanisms involved in the development of the choriocapillaris. We show for the first time that zebrafish have a choriocapillaris highly similar to that in mammals, and that it is initially formed by a novel process of synchronized vasculogenesis occurring simultaneously across the entire outer retina. This initial vascular network expands by un-inhibited sprouting angiogenesis whereby all endothelial cells adopt tip-cell characteristics, a process which is sustained throughout embryonic and early post-natal development, even after the choriocapillaris becomes perfused. Ubiquitous sprouting was maintained by continuous VEGF-VEGFR2 signaling in endothelial cells delaying maturation until immediately before stages where vision becomes important for survival, leading to the unparalleled high density and lobular structure of this vasculature. Sprouting was throughout development limited to two dimensions by Bruchs membrane and the sclera at the anterior and posterior surfaces respectively. These novel cellular and molecular mechanisms underlying choriocapillaris development were recapitulated in mice. In conclusion, our findings reveal novel mechanisms underlying the development of the choriocapillaris during zebrafish and mouse development. These results may explain the uniquely high density and sheet-like organization of this vasculature.
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| 2. |
- Ando, Koji, et al.
(författare)
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Conserved and context-dependent roles for pdgfrb signaling during zebrafish vascular mural cell development
- 2021
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Ingår i: Developmental Biology. - : Elsevier. - 0012-1606 .- 1095-564X. ; 479, s. 11-22
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Tidskriftsartikel (refereegranskat)abstract
- Platelet derived growth factor beta and its receptor, Pdgfrb, play essential roles in the development of vascular mural cells, including pericytes and vascular smooth muscle cells. To determine if this role was conserved in zebrafish, we analyzed pdgfb and pdgfrb mutant lines. Similar to mouse, pdgfb and pdgfrb mutant zebrafish lack brain pericytes and exhibit anatomically selective loss of vascular smooth muscle coverage. Despite these defects, pdgfrb mutant zebrafish did not otherwise exhibit circulatory defects at larval stages. However, beginning at juvenile stages, we observed severe cranial hemorrhage and vessel dilation associated with loss of pericytes and vascular smooth muscle cells in pdgfrb mutants. Similar to mouse, pdgfrb mutant zebrafish also displayed structural defects in the glomerulus, but normal development of hepatic stellate cells. We also noted defective mural cell investment on coronary vessels with concomitant defects in their development. Together, our studies support a conserved requirement for Pdgfrb signaling in mural cells. In addition, these zebrafish mutants provide an important model for definitive investigation of mural cells during early embryonic stages without confounding secondary effects from circulatory defects.
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| 3. |
- Garcia-Concejo, Adrian, et al.
(författare)
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Protein kinase C family evolution in jawed vertebrates
- 2021
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Ingår i: Developmental Biology. - : Elsevier. - 0012-1606 .- 1095-564X. ; 479, s. 77-90
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Tidskriftsartikel (refereegranskat)abstract
- Protein kinase C (PKC) was one of the first kinases identified in human cells. It is now known to constitute a family of kinases that respond to diacylglycerol, phosphatidylserine and for some family members, Ca2+. They have a plethora of different functions, such as cell cycle regulation, immune response and memory formation. In mammals, 12 PKC family members have been described, usually divided into 4 different subfamilies. We present here a comprehensive evolutionary analysis of the PKC genes in jawed vertebrates with special focus on the impact of the two tetraploidizations (1R and 2R) before the radiation of jawed vertebrates and the teleost tetraploidization (3R), as illuminated by synteny and paralogon analysis including many neighboring gene families. We conclude that the vertebrate predecessor had five PKC genes, as tunicates and lancelets still do, and that the PKC family should therefore ideally be organized into five subfamilies. The 1R and 2R events led to a total of 12 genes distributed among these five subfamilies. All 12 genes are still present in some of the major lineages of jawed vertebrates, including mammals, whereas birds and cartilaginous fishes have lost one member. The 3R event added another nine genes in teleosts, bringing the total to 21 genes. The zebrafish, a common experimental model animal, has retained 19. We have found no independent gene duplications. Thus, the genome doublings completely account for the complexity of this gene family in jawed vertebrates and have thereby had a huge impact on their evolution.
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| 4. |
- Gorgoń, Szymon, et al.
(författare)
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The apical cell - An enigmatic somatic cell in leech ovaries - Structure and putative functions
- 2021
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Ingår i: Developmental Biology. - : Elsevier. - 0012-1606 .- 1095-564X. ; 469, s. 111-124
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Tidskriftsartikel (refereegranskat)abstract
- Although somatic cells play an integral role in animal gametogenesis, their organization and function are usually poorly characterized, especially in non-model systems. One such example is a peculiar cell found in leech ovaries – the apical cell (AC). A single AC can be found at the apical tip of each ovary cord, the functional unit of leech ovaries, where it is surrounded by other somatic and germline cells. The AC is easily distinguished due to its enormous size and its numerous long cytoplasmic projections that penetrate the space between neighboring cells. It is also characterized by a prominent accumulation of mitochondria, Golgi complexes and electron-dense vesicles. ACs are also enriched in cytoskeleton, mainly in form of intermediate filaments. Additionally, the AC is connected to neighboring cells via junctions that structurally resemble hemidesmosomes. In spite of numerous descriptive data about the AC, its functions remain poorly understood. Its suggested functions include a role in forming skeleton for the germline cells, and a role in defining a niche for germline stem cells. The latter is more speculative, since germline stem cells have not been identified in leech ovaries. Somatic cells with similar morphological properties to those of the AC have been found in gonads of nematodes – the distal tip cell – and in insects – Verson’s cell, hub cells and cap cells. In the present article we summarize information about the AC structure and its putative functions. AC is compared with other well-described somatic cells with potentially similar roles in gametogenesis.
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| 5. |
- Iglesias Gonzalez, Ana Belen, et al.
(författare)
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Perturbed development of calb2b expressing dI6 interneurons and motor neurons underlies locomotor defects observed in calretinin knock-down zebrafish larvae
- 2024
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Ingår i: Developmental Biology. - : Elsevier. - 0012-1606 .- 1095-564X. ; 508, s. 77-87
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Tidskriftsartikel (refereegranskat)abstract
- Calcium binding proteins are essential for neural development and cellular activity. Calretinin, encoded by calb2a and calb2b, plays a role during early zebrafish development and has been proposed as a marker for distinct neuronal populations within the locomotor network. We generated a calb2b:hs:eGFP transgenic reporter line to characterize calretinin expressing cells in the developing spinal cord and describe morphological and behavioral defects in calretinin knock-down larvae. eGFP was detected in primary and secondary motor neurons, as well as in dI6 and V0v interneurons. Knock-down of calretinin lead to disturbed development of motor neurons and dI6 interneurons, revealing a crucial role during early development of the locomotor network. Primary motor neurons showed delayed axon outgrowth and the distinct inhibitory CoLo neurons, originating from the dI6 lineage, were absent. These observations explain the locomotor defects we observed in calretinin knock-down animals where the velocity, acceleration and coordination were affected during escapes. Altogether, our analysis suggests an essential role for calretinin during the development of the circuits regulating escape responses and fast movements within the locomotor network.
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| 6. |
- Papadogiannis, Vasileios, et al.
(författare)
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Evolution of the expression and regulation of the nuclear hormone receptor ERR gene family in the chordate lineage
- 2023
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Ingår i: Developmental Biology. - 0012-1606 .- 1095-564X. ; 504, s. 12-24
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Tidskriftsartikel (refereegranskat)abstract
- The Estrogen Related Receptor (ERR) nuclear hormone receptor genes have a wide diversity of roles in vertebrate development. In embryos, ERR genes are expressed in several tissues, including the central and peripheral nervous systems. Here we seek to establish the evolutionary history of chordate ERR genes, their expression and their regulation. We examine ERR expression in mollusc, amphioxus and sea squirt embryos, finding the single ERR orthologue is expressed in the nervous system in all three, with muscle expression also found in the two chordates. We show that most jawed vertebrates and lampreys have four ERR paralogues, and that vertebrate ERR genes were ancestrally linked to Estrogen Receptor genes. One of the lamprey paralogues shares conserved expression domains with jawed vertebrate ERRγ in the embryonic vestibuloacoustic ganglion, eye, brain and spinal cord. Hypothesising that conserved expression derives from conserved regulation, we identify a suite of pan-vertebrate conserved non-coding sequences in ERR introns. We use transgenesis in lamprey and chicken embryos to show that these sequences are regulatory and drive reporter gene expression in the nervous system. Our data suggest an ancient association between ERR and the nervous system, including expression in cells associated with photosensation and mechanosensation. This includes the origin in the vertebrate common ancestor of a suite of regulatory elements in the 3’ introns that drove nervous system expression and have been conserved from this point onwards.
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| 7. |
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| 8. |
- Vogeler, Susanne, et al.
(författare)
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Cloning and characterisation of NMDA receptors in the Pacific oyster, Crassostrea gigas (Thunberg, 1793) in relation to metamorphosis and catecholamine synthesis
- 2021
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Ingår i: Developmental Biology. - : Elsevier BV. - 0012-1606 .- 1095-564X. ; 469, s. 144-59
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Tidskriftsartikel (refereegranskat)abstract
- © 2020 Elsevier Inc. Bivalve metamorphosis is a developmental transition from a free-living larva to a benthic juvenile (spat), regulated by a complex interaction of neurotransmitters and neurohormones such as L-DOPA and epinephrine (catecholamine). We recently suggested an N-Methyl-D-aspartate (NMDA) receptor pathway as an additional and previously unknown regulator of bivalve metamorphosis. To explore this theory further, we successfully induced metamorphosis in the Pacific oyster, Crassostrea gigas, by exposing competent larvae to L-DOPA, epinephrine, MK-801 and ifenprodil. Subsequently, we cloned three NMDA receptor subunits CgNR1, CgNR2A and CgNR2B, with sequence analysis suggesting successful assembly of functional NMDA receptor complexes and binding to natural occurring agonists and the channel blocker MK-801. NMDA receptor subunits are expressed in competent larvae, during metamorphosis and in spat, but this expression is neither self-regulated nor regulated by catecholamines. In-situ hybridisation of CgNR1 in competent larvae identified NMDA receptor presence in the apical organ/cerebral ganglia area with a potential sensory function, and in the nervous network of the foot indicating an additional putative muscle regulatory function. Furthermore, phylogenetic analyses identified molluscan-specific gene expansions of key enzymes involved in catecholamine biosynthesis. However, exposure to MK-801 did not alter the expression of selected key enzymes, suggesting that NMDA receptors do not regulate the biosynthesis of catecholamines via gene expression.
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| 9. |
- Ward, Rebecca, et al.
(författare)
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Pharmacological restoration of visual function in a zebrafish model of von-Hippel Lindau disease
- 2020
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Ingår i: Developmental Biology. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0012-1606 .- 1095-564X. ; 457:2, s. 226-234
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Tidskriftsartikel (refereegranskat)abstract
- Von Hippel-Lindau (VHL) syndrome is a rare, autosomal dominant disorder, characterised by hypervascularised tumour formation in multiple organ systems. Vision loss associated with retinal capillary hemangioblastomas remains one of the earliest complications of VHL disease. The mortality of Vhl(-/-) mice in utero restricted modelling of VHL disease in this mammalian model. Zebrafish harbouring a recessive germline mutation in the vhl gene represent a viable, alternative vertebrate model to investigate associated ocular loss-of-function phenotypes. Previous studies reported neovascularisation of the brain, eye and trunk together with oedema in the vhl(-/-) zebrafish eye. In this study, we demonstrate vhl(-/-) zebrafish almost entirely lack visual function. Furthermore, hyaloid vasculature networks in the vhl(-/-) eye are improperly formed and this phenotype is concomitant with development of an ectopic intraretinal vasculature. Sunitinib malate, a multi tyrosine kinase inhibitor, market authorised for cancer, reversed the ocular behavioural and morphological phenotypes observed in vhl(-/-) zebrafish. We conclude that the zebrafish yid gene contributes to an endogenous molecular barrier that prevents development of intraretinal vasculature, and that pharmacological intervention with sunitinib can improve visual function and hyaloid vessel patterning while reducing abnormally formed ectopic intraretinal vessels in vhl(-/-) zebrafish.
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| 10. |
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| 11. |
- Lester, Stephen, et al.
(författare)
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Quantum Unique Ergodicity for half-integral weight automorphic forms
- 2020
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Ingår i: Duke mathematical journal. - : Duke University Press. - 0012-7094 .- 1547-7398. ; 169:2, s. 279-351
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the analogue of the quantum unique ergodicity (QUE) conjecture for half-integral weight automorphic forms. Assuming the generalized Riemann hypothesis (GRH), we establish both QUE for half-integral weight Hecke Maa beta cusp forms for Gamma(0)(4) lying in Kohnen's plus subspace and mass equidistribution for half-integral weight holomorphic Hecke cusp forms for Gamma(0)(4) lying in Kohnen's plus subspace. By combining the former result along with an argument of Rudnick, it follows that under GRH the zeros of these holomorphic Hecke cusp forms equidistribute with respect to hyperbolic measure on Gamma(0) (4)\H as the weight tends to infinity.
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| 12. |
- Bruzzaniti, Sara, et al.
(författare)
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High levels of blood circulating immune checkpoint molecules in children with new-onset type 1 diabetes are associated with the risk of developing an additional autoimmune disease
- 2022
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Ingår i: Diabetologia. - : SPRINGER. - 0012-186X .- 1432-0428. ; 65, s. 1390-1397
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis We assessed the levels of blood circulating immune checkpoint molecules (ICMs) at diagnosis of type 1 diabetes, and determined their association with the risk of developing an additional autoimmune disorder over time. Methods Children with new-onset type 1 diabetes (n = 143), without biological and/or clinical signs of additional autoimmune disorders, and healthy children (n = 75) were enrolled, and blood circulating levels of 14 ICMs were measured. The children with type 1 diabetes were divided into two groups on the basis of the development of an additional autoimmune disease in the 5 years after diabetes onset. Differences in soluble ICM levels between the groups were assessed, and a Cox regression analysis was used to evaluate their association with the risk of development of an additional autoimmune disease over time. To validate the data, circulating ICMs were measured in an independent cohort of 60 children with new-onset type 1 diabetes stratified into two groups. Results We found that the levels of circulating ICMs were significantly higher in children with new-onset diabetes compared with healthy children. Further, we observed that children with type 1 diabetes who developed a second autoimmune disease over time (T1D-AAD(+) children) had higher levels of soluble ICMs than children with type 1 diabetes who did not (T1D-AAD(-) children). Cox regression models revealed that high circulating levels of CD137/4-1BB and PD-1 molecules at diabetes diagnosis were associated with the risk of developing an additional autoimmune disease in both type 1 diabetes cohorts. Conclusions/interpretation Our findings suggest that soluble CD137/4-1BB and PD-1 molecules may be used as prognostic biomarkers in children with type 1 diabetes, and may pave the way for novel immunological screening at diabetes onset, allowing early identification of children at higher risk of developing other autoimmune conditions over time.
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