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Advances in Experimental Medicine and... 2024Congenital anomalies and acquired diseases of the coronary blood vessels are of great clinical relevance. The early diagnosis of these conditions remains, however,... (Review)
Review
Congenital anomalies and acquired diseases of the coronary blood vessels are of great clinical relevance. The early diagnosis of these conditions remains, however, challenging. In order to improve our knowledge of these ailments, progress has to be achieved in the research of the molecular and cellular mechanisms that control development of the coronary vascular bed. The aim of this chapter is to provide a succint account of the key elements of coronary blood vessel development, especially in the context of the role played by the epicardium and epicardial cellular derivatives. We will discuss the importance of the epicardium in coronary blood vessel morphogenesis, from the contribution of the epicardially derived mesenchyme to these blood vessels to its role as an instructive signaling center, attempting to relate these concepts to the origin of coronary disease.
Topics: Pericardium; Humans; Coronary Vessels; Animals; Signal Transduction; Mesoderm; Morphogenesis
PubMed: 38884710
DOI: 10.1007/978-3-031-44087-8_8 -
Molecular Neurobiology Nov 2023Moyamoya disease (MMD) is a rare cerebrovascular disorder characterized by progressive occlusion of the internal carotid artery and the formation of an abnormal...
Moyamoya disease (MMD) is a rare cerebrovascular disorder characterized by progressive occlusion of the internal carotid artery and the formation of an abnormal compensatory capillary network at the base of the brain. Genomics studies identified Ring finger protein 213 (RNF213) as a common genetic factor that increases the susceptibility to MMD in East Asian people. However, the function of RNF213 and its roles in pathogenesis of MMD is unclear. Here, we showed that genetic knockout of Rnf213 in mice causes significant pericyte reduction and blood-brain barrier impairment in the cortex. These phenotypes are accompanied with microglia activation and elevated level of proinflammatory cytokines. Additionally, Rnf213-deficient mice showed reduced expression of tight junction proteins, including Occludin, Claudin-5, and ZO-1. Together, these data suggested that RNF213 might contribute to the pathogenesis of MMD through disruption of pericyte homeostasis and blood-brain barrier integrity by dysregulation of inflammatory responses and tight junction formation.
Topics: Humans; Mice; Animals; Blood-Brain Barrier; Pericytes; Genetic Predisposition to Disease; Ubiquitin-Protein Ligases; Mice, Knockout; Transcription Factors; Adenosine Triphosphatases
PubMed: 37438553
DOI: 10.1007/s12035-023-03480-y -
Diabetologia Nov 2023The loss of pericytes surrounding the retinal vasculature in early diabetic retinopathy underlies changes to the neurovascular unit that lead to more destructive forms...
AIMS/HYPOTHESIS
The loss of pericytes surrounding the retinal vasculature in early diabetic retinopathy underlies changes to the neurovascular unit that lead to more destructive forms of the disease. However, it is unclear which changes lead to loss of retinal pericytes. This study investigated the hypothesis that chronic increases in one or more inflammatory factors mitigate the signalling pathways needed for pericyte survival.
METHODS
Loss of pericytes and levels of inflammatory markers at the mRNA and protein levels were investigated in two genetic models of diabetes, Ins2 (a model of type 1 diabetes) and Lepr (a model of type 2 diabetes), at early stages of diabetic retinopathy. In addition, changes that accompany gliosis and the retinal vasculature were determined. Finally, changes in retinal pericytes chronically incubated with vehicle or increasing amounts of IFNγ were investigated to determine the effects on pericyte survival. The numbers of pericytes, microglia, astrocytes and endothelial cells in retinal flatmounts were determined by immunofluorescence. Protein and mRNA levels of inflammatory factors were determined using multiplex ELISAs and quantitative reverse transcription PCR (qRT-PCR). The effects of IFNγ on the murine retinal pericyte survival-related platelet-derived growth factor receptor β (PDGFRβ) signalling pathway were investigated by western blot analysis. Finally, the levels of cell death-associated protein kinase C isoform delta (PKCδ) and cleaved caspase 3 (CC3) in pericytes were determined by western blot analysis and immunocytochemistry.
RESULTS
The essential findings of this study were that both type 1 and 2 diabetes were accompanied by a similar progression of retinal pericyte loss, as well as gliosis. However, inflammatory factor expression was dissimilar in the two models of diabetes, with peak expression occurring at different ages for each model. Retinal vascular changes were more severe in the type 2 diabetes model. Chronic incubation of murine retinal pericytes with IFNγ decreased PDGFRβ signalling and increased the levels of active PKCδ and CC3.
CONCLUSIONS/INTERPRETATION
We conclude that retinal inflammation is involved in and sustains pericyte loss as diabetic retinopathy progresses. Moreover, IFNγ plays a critical role in reducing pericyte survival in the retina by reducing activation of the PDGFRβ signalling pathway and increasing PKCδ levels and pericyte apoptosis.
Topics: Mice; Animals; Diabetic Retinopathy; Disease Models, Animal; Diabetes Mellitus, Type 2; Diabetes Mellitus, Type 1; Endothelial Cells; Gliosis; Diabetes Mellitus, Experimental; Retina; Inflammation; RNA, Messenger; Pericytes
PubMed: 37670018
DOI: 10.1007/s00125-023-05995-4 -
Brain : a Journal of Neurology Mar 2024Incomplete reperfusion of the microvasculature ('no-reflow') after ischaemic stroke damages salvageable brain tissue. Previous ex vivo studies suggest pericytes are...
Incomplete reperfusion of the microvasculature ('no-reflow') after ischaemic stroke damages salvageable brain tissue. Previous ex vivo studies suggest pericytes are vulnerable to ischaemia and may exacerbate no-reflow, but the viability of pericytes and their association with no-reflow remains under-explored in vivo. Using longitudinal in vivo two-photon single-cell imaging over 7 days, we showed that 87% of pericytes constrict during cerebral ischaemia and remain constricted post reperfusion, and 50% of the pericyte population are acutely damaged. Moreover, we revealed ischaemic pericytes to be fundamentally implicated in capillary no-reflow by limiting and arresting blood flow within the first 24 h post stroke. Despite sustaining acute membrane damage, we observed that over half of all cortical pericytes survived ischaemia and responded to vasoactive stimuli, upregulated unique transcriptomic profiles and replicated. Finally, we demonstrated the delayed recovery of capillary diameter by ischaemic pericytes after reperfusion predicted vessel reconstriction in the subacute phase of stroke. Cumulatively, these findings demonstrate that surviving cortical pericytes remain both viable and promising therapeutic targets to counteract no-reflow after ischaemic stroke.
Topics: Humans; Stroke; Pericytes; Brain Ischemia; Ischemic Stroke; Cerebral Infarction
PubMed: 38153327
DOI: 10.1093/brain/awad401 -
Stem Cell Reports Oct 2023The formation of vascular structures is fundamental for in vitro tissue engineering. Vascularization can enable the nutrient supply within larger structures and...
The formation of vascular structures is fundamental for in vitro tissue engineering. Vascularization can enable the nutrient supply within larger structures and increase transplantation efficiency. We differentiated human induced pluripotent stem cells toward endothelial cells in 3D suspension culture. To investigate in vitro neovascularization and various 3D microenvironmental approaches, we designed a comprehensive single-cell transcriptomic study. Time-resolved single-cell transcriptomics of the endothelial and co-evolving mural cells gave insights into cell type development, stability, and plasticity. Transfer to a 3D hydrogel microenvironment induced neovascularization and facilitated tracing of migrating, coalescing, and tubulogenic endothelial cell states. During maturation, we monitored two pericyte subtypes evolving mural cells. Profiling cell-cell interactions between pericytes and endothelial cells revealed angiogenic signals during tubulogenesis. In silico discovered ligands were tested for their capability to attract endothelial cells. Our data, analyses, and results provide an in vitro roadmap to guide vascularization in future tissue engineering.
Topics: Humans; Endothelial Cells; Induced Pluripotent Stem Cells; Neovascularization, Physiologic; Coculture Techniques; Neovascularization, Pathologic; Pericytes
PubMed: 37714147
DOI: 10.1016/j.stemcr.2023.08.008 -
Stem Cell Reviews and Reports Oct 2023In the last two decades, considerable progress has been made in the derivation of mammalian germ cells from pluripotent stem cells such as Embryonic Stem Cells (ESCs)...
In the last two decades, considerable progress has been made in the derivation of mammalian germ cells from pluripotent stem cells such as Embryonic Stem Cells (ESCs) and induced Pluripotent Stem Cells (iPSCs). The pluripotent stem cells are generally first induced into pre-gastrulating endoderm/mesoderm-like status and then specified into putative primordial germ cells (PGCs) termed PGC-like cells (PGCLCs) which possess the potential to generate oocytes and sperms. Adipose-derived mesenchymal stromal cells (ASCs) are multipotent cells, having the capacity to differentiate into cell types such as adipocytes, osteocytes and chondrocytes. Since no information is available about the capability of female human ASCs (hASCs) to generate PGCLCs, we compared protocols to produce such cells from hASCs themselves or from hASC-derived iPSCs. The results showed that, providing pre-induction into a peri-gastrulating endoderm/mesoderm-like status, hASCs can generate PGCLCs. This process, however, shows a lower efficiency than when hASC-derived iPSCs are used as starting cells. Although hASCs possess multipotency and express mesodermal genes, direct induction into PGCLCs resulted less efficient.
Topics: Animals; Humans; Female; Germ Cells; Pluripotent Stem Cells; Embryonic Stem Cells; Induced Pluripotent Stem Cells; Mesenchymal Stem Cells; Mammals
PubMed: 37338786
DOI: 10.1007/s12015-023-10561-x -
BioRxiv : the Preprint Server For... Oct 2023During heart development, a well-characterized network of transcription factors initiates cardiac gene expression and defines the precise timing and location of cardiac...
During heart development, a well-characterized network of transcription factors initiates cardiac gene expression and defines the precise timing and location of cardiac progenitor specification. However, our understanding of the post-initiation transcriptional events that regulate cardiac gene expression is still incomplete. The PAF1C component Rtf1 is a transcription regulatory protein that modulates pausing and elongation of RNA Pol II, as well as cotranscriptional histone modifications. Here we report that Rtf1 is essential for cardiogenesis in fish and mammals, and that in the absence of Rtf1 activity, cardiac progenitors arrest in an immature state. We found that Rtf1's Plus3 domain, which confers interaction with the transcriptional pausing and elongation regulator Spt5, was necessary for cardiac progenitor formation. ChIP-seq analysis further revealed changes in the occupancy of RNA Pol II around the transcription start site (TSS) of cardiac genes in morphants reflecting a reduction in transcriptional pausing. Intriguingly, inhibition of pause release in morphants and mutants restored the formation of cardiac cells and improved Pol II occupancy at the TSS of key cardiac genes. Our findings highlight the crucial role that transcriptional pausing plays in promoting normal gene expression levels in a cardiac developmental context.
PubMed: 37873297
DOI: 10.1101/2023.10.13.562296 -
International Journal of Molecular... Aug 2023The tumor microenvironment (TME) is complex and involves many different cell types that seemingly work together in helping cancer cells evade immune monitoring and... (Review)
Review
The tumor microenvironment (TME) is complex and involves many different cell types that seemingly work together in helping cancer cells evade immune monitoring and survive therapy. The advent of single-cell sequencing has greatly increased our knowledge of the cell types present in the tumor microenvironment and their role in the developing cancer. This, coupled with clinical data showing that cancer development and the response to therapy may be influenced by drugs that indirectly influence the tumor environment, highlights the need to better understand how the cells present in the TME work together. This review looks at the different cell types (cancer cells, cancer stem cells, endothelial cells, pericytes, adipose cells, cancer-associated fibroblasts, and neuronal cells) in the bladder tumor microenvironment. Their impact on immune activation and on shaping the microenvironment are discussed as well as the effects of hypertensive drugs and anesthetics on bladder cancer.
Topics: Humans; Urinary Bladder; Tumor Microenvironment; Endothelial Cells; Neoplasms; Urinary Bladder Neoplasms; Pericytes
PubMed: 37569686
DOI: 10.3390/ijms241512311 -
Current Topics in Developmental Biology 2024The Segmentation Clock is a tissue-level patterning system that enables the segmentation of the vertebral column precursors into transient multicellular blocks called... (Review)
Review
The Segmentation Clock is a tissue-level patterning system that enables the segmentation of the vertebral column precursors into transient multicellular blocks called somites. This patterning system comprises a set of elements that are essential for correct segmentation. Under the so-called "Clock and Wavefront" model, the system consists of two elements, a genetic oscillator that manifests itself as traveling waves of gene expression, and a regressing wavefront that transforms the temporally periodic signal encoded in the oscillations into a permanent spatially periodic pattern of somite boundaries. Over the last twenty years, every new discovery about the Segmentation Clock has been tightly linked to the nomenclature of the "Clock and Wavefront" model. This constrained allocation of discoveries into these two elements has generated long-standing debates in the field as what defines molecularly the wavefront and how and where the interaction between the two elements establishes the future somite boundaries. In this review, we propose an expansion of the "Clock and Wavefront" model into three elements, "Clock", "Wavefront" and signaling gradients. We first provide a detailed description of the components and regulatory mechanisms of each element, and we then examine how the spatiotemporal integration of the three elements leads to the establishment of the presumptive somite boundaries. To be as exhaustive as possible, we focus on the Segmentation Clock in zebrafish. Furthermore, we show how this three-element expansion of the model provides a better understanding of the somite formation process and we emphasize where our current understanding of this patterning system remains obscure.
Topics: Animals; Body Patterning; Gene Expression Regulation, Developmental; Somites; Mesoderm; Zebrafish; Signal Transduction; Biological Clocks
PubMed: 38729682
DOI: 10.1016/bs.ctdb.2023.11.001 -
Acta Neurologica Belgica Jun 2024The functional structure of the blood-brain barrier (BBB) deteriorates after stroke by developing diffuse microvascular and neurovascular dysfunction and loss of white... (Review)
Review
The functional structure of the blood-brain barrier (BBB) deteriorates after stroke by developing diffuse microvascular and neurovascular dysfunction and loss of white matter integrity. This causes nervous tissue injury and causes sensory and motor disabilities in stroke patients. Improving the integrity of the BBB and neurovascular remodeling after stroke can promote post-stroke injury conditions. Pericytes are contractile cells abundant in the BBB and sandwiched between astrocytes and endothelial cells of the microvessels. Stroke could lead to the degeneration of pericytes in the BBB. However, recent evidence shows that promoting pericytes enhances BBB integrity and neurovascular remodeling. Furthermore, pericytes achieve multipotent properties under hypoxic conditions, allowing them to transdifferentiate into the brain resident cells such as microglia. Microglia regulate immunity and inflammatory response after stroke. The current review studies recent findings in the intervening mechanisms underlying the regulatory effect of pericytes in BBB recovery after stroke.
Topics: Pericytes; Humans; Blood-Brain Barrier; Ischemic Stroke; Animals
PubMed: 37805645
DOI: 10.1007/s13760-023-02391-y