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Kurtyka M, Wessely F, Bau S, Ifie E, He L, de Wit NM, Pedersen ABV, Keller M, Webber C, de Vries HE, Ansorge O, Betsholtz C, De Bock M, Chaves C, Brodin B, Nielsen MS, Neuhaus W, Bell RD, Letoha T, Meyer AH, Leparc G, Lenter M, Lesuisse D, Cader ZM, Buckley ST, Loryan I, Pietrzik CU. The solute carrier SLC7A1 may act as a protein transporter at the blood-brain barrier. Eur J Cell Biol 2024; 103:151406. [PMID: 38547677 DOI: 10.1016/j.ejcb.2024.151406] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 03/02/2024] [Accepted: 03/20/2024] [Indexed: 06/29/2024] Open
Abstract
Despite extensive research, targeted delivery of substances to the brain still poses a great challenge due to the selectivity of the blood-brain barrier (BBB). Most molecules require either carrier- or receptor-mediated transport systems to reach the central nervous system (CNS). These transport systems form attractive routes for the delivery of therapeutics into the CNS, yet the number of known brain endothelium-enriched receptors allowing the transport of large molecules into the brain is scarce. Therefore, to identify novel BBB targets, we combined transcriptomic analysis of human and murine brain endothelium and performed a complex screening of BBB-enriched genes according to established selection criteria. As a result, we propose the high-affinity cationic amino acid transporter 1 (SLC7A1) as a novel candidate for transport of large molecules across the BBB. Using RNA sequencing and in situ hybridization assays, we demonstrated elevated SLC7A1 gene expression in both human and mouse brain endothelium. Moreover, we confirmed SLC7A1 protein expression in brain vasculature of both young and aged mice. To assess the potential of SLC7A1 as a transporter for larger proteins, we performed internalization and transcytosis studies using a radiolabelled or fluorophore-labelled anti-SLC7A1 antibody. Our results showed that SLC7A1 internalised a SLC7A1-specific antibody in human colorectal carcinoma (HCT116) cells. Moreover, transcytosis studies in both immortalised human brain endothelial (hCMEC/D3) cells and primary mouse brain endothelial cells clearly demonstrated that SLC7A1 effectively transported the SLC7A1-specific antibody from luminal to abluminal side. Therefore, here in this study, we present for the first time the SLC7A1 as a novel candidate for transport of larger molecules across the BBB.
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Mocci G, Sukhavasi K, Örd T, Bankier S, Singha P, Arasu UT, Agbabiaje OO, Mäkinen P, Ma L, Hodonsky CJ, Aherrahrou R, Muhl L, Liu J, Gustafsson S, Byandelger B, Wang Y, Koplev S, Lendahl U, Owens GK, Leeper NJ, Pasterkamp G, Vanlandewijck M, Michoel T, Ruusalepp A, Hao K, Ylä-Herttuala S, Väli M, Järve H, Mokry M, Civelek M, Miller CJ, Kovacic JC, Kaikkonen MU, Betsholtz C, Björkegren JL. Single-Cell Gene-Regulatory Networks of Advanced Symptomatic Atherosclerosis. Circ Res 2024; 134:1405-1423. [PMID: 38639096 PMCID: PMC11122742 DOI: 10.1161/circresaha.123.323184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 04/01/2024] [Accepted: 04/04/2024] [Indexed: 04/20/2024]
Abstract
BACKGROUND While our understanding of the single-cell gene expression patterns underlying the transformation of vascular cell types during the progression of atherosclerosis is rapidly improving, the clinical and pathophysiological relevance of these changes remains poorly understood. METHODS Single-cell RNA sequencing data generated with SmartSeq2 (≈8000 genes/cell) in 16 588 single cells isolated during atherosclerosis progression in Ldlr-/-Apob100/100 mice with human-like plasma lipoproteins and from humans with asymptomatic and symptomatic carotid plaques was clustered into multiple subtypes. For clinical and pathophysiological context, the advanced-stage and symptomatic subtype clusters were integrated with 135 tissue-specific (atherosclerotic aortic wall, mammary artery, liver, skeletal muscle, and visceral and subcutaneous, fat) gene-regulatory networks (GRNs) inferred from 600 coronary artery disease patients in the STARNET (Stockholm-Tartu Atherosclerosis Reverse Network Engineering Task) study. RESULTS Advanced stages of atherosclerosis progression and symptomatic carotid plaques were largely characterized by 3 smooth muscle cells (SMCs), and 3 macrophage subtype clusters with extracellular matrix organization/osteogenic (SMC), and M1-type proinflammatory/Trem2-high lipid-associated (macrophage) phenotypes. Integrative analysis of these 6 clusters with STARNET revealed significant enrichments of 3 arterial wall GRNs: GRN33 (macrophage), GRN39 (SMC), and GRN122 (macrophage) with major contributions to coronary artery disease heritability and strong associations with clinical scores of coronary atherosclerosis severity. The presence and pathophysiological relevance of GRN39 were verified in 5 independent RNAseq data sets obtained from the human coronary and aortic artery, and primary SMCs and by targeting its top-key drivers, FRZB and ALCAM in cultured human coronary artery SMCs. CONCLUSIONS By identifying and integrating the most gene-rich single-cell subclusters of atherosclerosis to date with a coronary artery disease framework of GRNs, GRN39 was identified and independently validated as being critical for the transformation of contractile SMCs into an osteogenic phenotype promoting advanced, symptomatic atherosclerosis.
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MESH Headings
- Humans
- Single-Cell Analysis
- Animals
- Gene Regulatory Networks
- Atherosclerosis/genetics
- Atherosclerosis/metabolism
- Atherosclerosis/pathology
- Mice
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Male
- Plaque, Atherosclerotic
- Disease Progression
- Female
- Macrophages/metabolism
- Macrophages/pathology
- Mice, Knockout
- Receptors, LDL/genetics
- Receptors, LDL/metabolism
- Mice, Inbred C57BL
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
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Zhou AX, Jeansson M, He L, Wigge L, Tonelius P, Tati R, Cederblad L, Muhl L, Uhrbom M, Liu J, Björnson Granqvist A, Lerman LO, Betsholtz C, Hansen PBL. Renal Endothelial Single-Cell Transcriptomics Reveals Spatiotemporal Regulation and Divergent Roles of Differential Gene Transcription and Alternative Splicing in Murine Diabetic Nephropathy. Int J Mol Sci 2024; 25:4320. [PMID: 38673910 PMCID: PMC11050020 DOI: 10.3390/ijms25084320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/04/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
Endothelial cell (EC) injury is a crucial contributor to the progression of diabetic kidney disease (DKD), but the specific EC populations and mechanisms involved remain elusive. Kidney ECs (n = 5464) were collected at three timepoints from diabetic BTBRob/ob mice and non-diabetic littermates. Their heterogeneity, transcriptional changes, and alternative splicing during DKD progression were mapped using SmartSeq2 single-cell RNA sequencing (scRNAseq) and elucidated through pathway, network, and gene ontology enrichment analyses. We identified 13 distinct transcriptional EC phenotypes corresponding to different kidney vessel subtypes, confirmed through in situ hybridization and immunofluorescence. EC subtypes along nephrons displayed extensive zonation related to their functions. Differential gene expression analyses in peritubular and glomerular ECs in DKD underlined the regulation of DKD-relevant pathways including EIF2 signaling, oxidative phosphorylation, and IGF1 signaling. Importantly, this revealed the differential alteration of these pathways between the two EC subtypes and changes during disease progression. Furthermore, glomerular and peritubular ECs also displayed aberrant and dynamic alterations in alternative splicing (AS), which is strongly associated with DNA repair. Strikingly, genes displaying differential transcription or alternative splicing participate in divergent biological processes. Our study reveals the spatiotemporal regulation of gene transcription and AS linked to DKD progression, providing insight into pathomechanisms and clues to novel therapeutic targets for DKD treatment.
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Schevenels G, Cabochette P, America M, Vandenborne A, De Grande L, Guenther S, He L, Dieu M, Christou B, Vermeersch M, Germano RFV, Perez-Morga D, Renard P, Martin M, Vanlandewijck M, Betsholtz C, Vanhollebeke B. A brain-specific angiogenic mechanism enabled by tip cell specialization. Nature 2024; 628:863-871. [PMID: 38570687 PMCID: PMC11041701 DOI: 10.1038/s41586-024-07283-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 03/07/2024] [Indexed: 04/05/2024]
Abstract
Vertebrate organs require locally adapted blood vessels1,2. The gain of such organotypic vessel specializations is often deemed to be molecularly unrelated to the process of organ vascularization. Here, opposing this model, we reveal a molecular mechanism for brain-specific angiogenesis that operates under the control of Wnt7a/b ligands-well-known blood-brain barrier maturation signals3-5. The control mechanism relies on Wnt7a/b-dependent expression of Mmp25, which we find is enriched in brain endothelial cells. CRISPR-Cas9 mutagenesis in zebrafish reveals that this poorly characterized glycosylphosphatidylinositol-anchored matrix metalloproteinase is selectively required in endothelial tip cells to enable their initial migration across the pial basement membrane lining the brain surface. Mechanistically, Mmp25 confers brain invasive competence by cleaving meningeal fibroblast-derived collagen IV α5/6 chains within a short non-collagenous region of the central helical part of the heterotrimer. After genetic interference with the pial basement membrane composition, the Wnt-β-catenin-dependent organotypic control of brain angiogenesis is lost, resulting in properly patterned, yet blood-brain-barrier-defective cerebrovasculatures. We reveal an organ-specific angiogenesis mechanism, shed light on tip cell mechanistic angiodiversity and thereby illustrate how organs, by imposing local constraints on angiogenic tip cells, can select vessels matching their distinctive physiological requirements.
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Vázquez-Liébanas E, Mocci G, Li W, Laviña B, Reddy A, O'Connor C, Hudson N, Elbeck Z, Nikoloudis I, Gaengel K, Vanlandewijck M, Campbell M, Betsholtz C, Mäe MA. Mosaic deletion of claudin-5 reveals rapid non-cell-autonomous consequences of blood-brain barrier leakage. Cell Rep 2024; 43:113911. [PMID: 38446668 DOI: 10.1016/j.celrep.2024.113911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 12/19/2023] [Accepted: 02/16/2024] [Indexed: 03/08/2024] Open
Abstract
Claudin-5 (CLDN5) is an endothelial tight junction protein essential for blood-brain barrier (BBB) formation. Abnormal CLDN5 expression is common in brain disease, and knockdown of Cldn5 at the BBB has been proposed to facilitate drug delivery to the brain. To study the consequences of CLDN5 loss in the mature brain, we induced mosaic endothelial-specific Cldn5 gene ablation in adult mice (Cldn5iECKO). These mice displayed increased BBB permeability to tracers up to 10 kDa in size from 6 days post induction (dpi) and ensuing lethality from 10 dpi. Single-cell RNA sequencing at 11 dpi revealed profound transcriptomic differences in brain endothelial cells regardless of their Cldn5 status in mosaic mice, suggesting major non-cell-autonomous responses. Reactive microglia and astrocytes suggested rapid cellular responses to BBB leakage. Our study demonstrates a critical role for CLDN5 in the adult BBB and provides molecular insight into the consequences and risks associated with CLDN5 inhibition.
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ElBeck Z, Hossain MB, Siga H, Oskolkov N, Karlsson F, Lindgren J, Walentinsson A, Koppenhöfer D, Jarvis R, Bürli R, Jamier T, Franssen E, Firth M, Degasperi A, Bendtsen C, Menzies RI, Streckfuss-Bömeke K, Kohlhaas M, Nickel AG, Lund LH, Maack C, Végvári Á, Betsholtz C. Epigenetic modulators link mitochondrial redox homeostasis to cardiac function in a sex-dependent manner. Nat Commun 2024; 15:2358. [PMID: 38509128 PMCID: PMC10954618 DOI: 10.1038/s41467-024-46384-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 02/23/2024] [Indexed: 03/22/2024] Open
Abstract
While excessive production of reactive oxygen species (ROS) is a characteristic hallmark of numerous diseases, clinical approaches that ameliorate oxidative stress have been unsuccessful. Here, utilizing multi-omics, we demonstrate that in cardiomyocytes, mitochondrial isocitrate dehydrogenase (IDH2) constitutes a major antioxidative defense mechanism. Paradoxically reduced expression of IDH2 associated with ventricular eccentric hypertrophy is counterbalanced by an increase in the enzyme activity. We unveil redox-dependent sex dimorphism, and extensive mutual regulation of the antioxidative activities of IDH2 and NRF2 by a feedforward network that involves 2-oxoglutarate and L-2-hydroxyglutarate and mediated in part through unconventional hydroxy-methylation of cytosine residues present in introns. Consequently, conditional targeting of ROS in a murine model of heart failure improves cardiac function in sex- and phenotype-dependent manners. Together, these insights may explain why previous attempts to treat heart failure with antioxidants have been unsuccessful and open new approaches to personalizing and, thereby, improving such treatment.
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Gupta RK, Niklasson M, Bergström T, Segerman A, Betsholtz C, Westermark B. Tumor-specific migration routes of xenotransplanted human glioblastoma cells in mouse brain. Sci Rep 2024; 14:864. [PMID: 38195678 PMCID: PMC10776844 DOI: 10.1038/s41598-023-51063-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/29/2023] [Indexed: 01/11/2024] Open
Abstract
The migration of neural progenitor cells (NPCs) to their final destination during development follows well-defined pathways, such as along blood vessels. Cells originating from the highly malignant tumor glioblastoma (GBM) seem to exploit similar routes for infiltrating the brain parenchyma. In this report, we have examined the migration of GBM cells using three-dimensional high-resolution confocal microscopy in brain tumors derived from eight different human GBM cell lines xenografted into immunodeficient mice. The primary invasion routes identified were long-distance migration along white matter tracts and local migration along blood vessels. We found that GBM cells in the majority of tumors (6 out of 8) did not exhibit association with blood vessels. These tumors, derived from low lamin A/C expressing GBM cells, were comparatively highly diffusive and invasive. Conversely, in 2 out of 8 tumors, we noted perivascular invasion and displacement of astrocyte end-feet. These tumors exhibited less diffusive migration, grew as solid tumors, and were distinguished by elevated expression of lamin A/C. We conclude that the migration pattern of glioblastoma is distinctly tumor cell-specific. Furthermore, the ability to invade the confined spaces within white matter tracts may necessitate low expression of lamin A/C, contributing to increased nuclear plasticity. This study highlights the role of GBM heterogeneity in driving the aggressive growth of glioblastoma.
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Pietilä R, Del Gaudio F, He L, Vázquez-Liébanas E, Vanlandewijck M, Muhl L, Mocci G, Bjørnholm KD, Lindblad C, Fletcher-Sandersjöö A, Svensson M, Thelin EP, Liu J, van Voorden AJ, Torres M, Antila S, Xin L, Karlström H, Storm-Mathisen J, Bergersen LH, Moggio A, Hansson EM, Ulvmar MH, Nilsson P, Mäkinen T, Andaloussi Mäe M, Alitalo K, Proulx ST, Engelhardt B, McDonald DM, Lendahl U, Andrae J, Betsholtz C. Molecular anatomy of adult mouse leptomeninges. Neuron 2023; 111:3745-3764.e7. [PMID: 37776854 DOI: 10.1016/j.neuron.2023.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 07/07/2023] [Accepted: 09/05/2023] [Indexed: 10/02/2023]
Abstract
Leptomeninges, consisting of the pia mater and arachnoid, form a connective tissue investment and barrier enclosure of the brain. The exact nature of leptomeningeal cells has long been debated. In this study, we identify five molecularly distinct fibroblast-like transcriptomes in cerebral leptomeninges; link them to anatomically distinct cell types of the pia, inner arachnoid, outer arachnoid barrier, and dural border layer; and contrast them to a sixth fibroblast-like transcriptome present in the choroid plexus and median eminence. Newly identified transcriptional markers enabled molecular characterization of cell types responsible for adherence of arachnoid layers to one another and for the arachnoid barrier. These markers also proved useful in identifying the molecular features of leptomeningeal development, injury, and repair that were preserved or changed after traumatic brain injury. Together, the findings highlight the value of identifying fibroblast transcriptional subsets and their cellular locations toward advancing the understanding of leptomeningeal physiology and pathology.
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9
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Mapunda JA, Pareja J, Vladymyrov M, Bouillet E, Hélie P, Pleskač P, Barcos S, Andrae J, Vestweber D, McDonald DM, Betsholtz C, Deutsch U, Proulx ST, Engelhardt B. VE-cadherin in arachnoid and pia mater cells serves as a suitable landmark for in vivo imaging of CNS immune surveillance and inflammation. Nat Commun 2023; 14:5837. [PMID: 37730744 PMCID: PMC10511632 DOI: 10.1038/s41467-023-41580-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 09/01/2023] [Indexed: 09/22/2023] Open
Abstract
Meninges cover the surface of the brain and spinal cord and contribute to protection and immune surveillance of the central nervous system (CNS). How the meningeal layers establish CNS compartments with different accessibility to immune cells and immune mediators is, however, not well understood. Here, using 2-photon imaging in female transgenic reporter mice, we describe VE-cadherin at intercellular junctions of arachnoid and pia mater cells that form the leptomeninges and border the subarachnoid space (SAS) filled with cerebrospinal fluid (CSF). VE-cadherin expression also marked a layer of Prox1+ cells located within the arachnoid beneath and separate from E-cadherin+ arachnoid barrier cells. In vivo imaging of the spinal cord and brain in female VE-cadherin-GFP reporter mice allowed for direct observation of accessibility of CSF derived tracers and T cells into the SAS bordered by the arachnoid and pia mater during health and neuroinflammation, and detection of volume changes of the SAS during CNS pathology. Together, the findings identified VE-cadherin as an informative landmark for in vivo imaging of the leptomeninges that can be used to visualize the borders of the SAS and thus potential barrier properties of the leptomeninges in controlling access of immune mediators and immune cells into the CNS during health and neuroinflammation.
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10
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Del Gaudio F, Liu D, Andaloussi Mäe M, Braune EB, Hansson EM, Wang QD, Betsholtz C, Lendahl U. Left ventricular hypertrophy and metabolic resetting in the Notch3-deficient adult mouse heart. Sci Rep 2023; 13:15022. [PMID: 37699967 PMCID: PMC10497627 DOI: 10.1038/s41598-023-42010-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/04/2023] [Indexed: 09/14/2023] Open
Abstract
The heart depends on a functional vasculature for oxygenation and transport of nutrients, and it is of interest to learn how primary impairment of the vasculature can indirectly affect cardiac function and heart morphology. Notch3-deficiency causes vascular smooth muscle cell (VSMC) loss in the vasculature but the consequences for the heart remain largely elusive. Here, we demonstrate that Notch3-/- mice have enlarged hearts with left ventricular hypertrophy and mild fibrosis. Cardiomyocytes were hypertrophic but not hyperproliferative, and the expression of several cardiomyocyte markers, including Tnt2, Myh6, Myh7 and Actn2, was altered. Furthermore, expression of genes regulating the metabolic status of the heart was affected: both Pdk4 and Cd36 were downregulated, indicating a metabolic switch from fatty acid oxidation to glucose consumption. Notch3-/- mice furthermore showed lower liver lipid content. Notch3 was expressed in heart VSMC and pericytes but not in cardiomyocytes, suggesting that a perturbation of Notch signalling in VSMC and pericytes indirectly impairs the cardiomyocytes. In keeping with this, Pdgfbret/ret mice, characterized by reduced numbers of VSMC and pericytes, showed left ventricular and cardiomyocyte hypertrophy. In conclusion, we demonstrate that reduced Notch3 or PDGFB signalling in vascular mural cells leads to cardiomyocyte dysfunction.
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11
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Peng D, Ando K, Hußmann M, Gloger M, Skoczylas R, Mochizuki N, Betsholtz C, Fukuhara S, Schulte-Merker S, Lawson ND, Koltowska K. Correction: Proper migration of lymphatic endothelial cells requires survival and guidance cues from arterial mural cells. eLife 2023; 12:90048. [PMID: 37307048 DOI: 10.7554/elife.90048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023] Open
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12
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Bell RD, Winkler EA, Singh I, Sagare AP, Deane R, Wu Z, Holtzman DM, Betsholtz C, Armulik A, Sallstrom J, Berk BC, Zlokovic BV. Author Correction: Apolipoprotein E controls cerebrovascular integrity via cyclophilin A. Nature 2023; 617:E12. [PMID: 37142785 DOI: 10.1038/s41586-023-06118-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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13
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Petkova M, Kraft M, Stritt S, Martinez-Corral I, Ortsäter H, Vanlandewijck M, Jakic B, Baselga E, Castillo SD, Graupera M, Betsholtz C, Mäkinen T. Immune-interacting lymphatic endothelial subtype at capillary terminals drives lymphatic malformation. J Exp Med 2023; 220:e20220741. [PMID: 36688917 PMCID: PMC9884640 DOI: 10.1084/jem.20220741] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 11/18/2022] [Accepted: 01/05/2023] [Indexed: 01/24/2023] Open
Abstract
Oncogenic mutations in PIK3CA, encoding p110α-PI3K, are a common cause of venous and lymphatic malformations. Vessel type-specific disease pathogenesis is poorly understood, hampering development of efficient therapies. Here, we reveal a new immune-interacting subtype of Ptx3-positive dermal lymphatic capillary endothelial cells (iLECs) that recruit pro-lymphangiogenic macrophages to promote progressive lymphatic overgrowth. Mouse model of Pik3caH1047R-driven vascular malformations showed that proliferation was induced in both venous and lymphatic ECs but sustained selectively in LECs of advanced lesions. Single-cell transcriptomics identified the iLEC population, residing at lymphatic capillary terminals of normal vasculature, that was expanded in Pik3caH1047R mice. Expression of pro-inflammatory genes, including monocyte/macrophage chemokine Ccl2, in Pik3caH1047R-iLECs was associated with recruitment of VEGF-C-producing macrophages. Macrophage depletion, CCL2 blockade, or anti-inflammatory COX-2 inhibition limited Pik3caH1047R-driven lymphangiogenesis. Thus, targeting the paracrine crosstalk involving iLECs and macrophages provides a new therapeutic opportunity for lymphatic malformations. Identification of iLECs further indicates that peripheral lymphatic vessels not only respond to but also actively orchestrate inflammatory processes.
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Bjørnholm KD, Del Gaudio F, Li H, Li W, Vazquez-Liebanas E, Mäe MA, Lendahl U, Betsholtz C, Nilsson P, Karlström H, Vanlandewijck M. A robust and efficient microvascular isolation method for multimodal characterization of the mouse brain vasculature. CELL REPORTS METHODS 2023; 3:100431. [PMID: 37056377 PMCID: PMC10088242 DOI: 10.1016/j.crmeth.2023.100431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/16/2023] [Accepted: 02/27/2023] [Indexed: 04/15/2023]
Abstract
Studying disease-related changes in the brain vasculature is warranted due to its crucial role in supplying oxygen and nutrients and removing waste and due to the anticipated vascular dysfunction in brain diseases. To this end, we have developed a protocol for fast and simple isolation of brain vascular fragments without the use of transgenic reporters. We used it to isolate and analyze 22,515 cells by single-cell RNA sequencing. The cells distributed into 23 distinct clusters corresponding to all known vascular and perivascular cell types in the brain. Western blot analysis also suggested that the protocol is suitable for proteomic analysis. We further adapted it for the establishment of primary cell cultures. The protocol generated highly reproducible results. In conclusion, we have developed a simple and robust brain vascular isolation protocol suitable for different experimental modalities, such as single-cell analyses, western blotting, and primary cell culture.
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Muhl L, Mocci G, Pietilä R, Liu J, He L, Genové G, Leptidis S, Gustafsson S, Buyandelger B, Raschperger E, Hansson EM, Björkegren JL, Vanlandewijck M, Lendahl U, Betsholtz C. A single-cell transcriptomic inventory of murine smooth muscle cells. Dev Cell 2022; 57:2426-2443.e6. [DOI: 10.1016/j.devcel.2022.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 09/12/2022] [Accepted: 09/27/2022] [Indexed: 11/28/2022]
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16
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Gillnäs S, Gallini R, He L, Betsholtz C, Andrae J. Severe cerebellar malformations in mutant mice demonstrate a role for PDGF-C/PDGFRα signalling in cerebellar development. Biol Open 2022; 11:275997. [PMID: 35876806 PMCID: PMC9382116 DOI: 10.1242/bio.059431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/08/2022] [Indexed: 11/20/2022] Open
Abstract
Formation of the mouse cerebellum is initiated in the embryo and continues for a few weeks after birth. Double mutant mice lacking platelet-derived growth factor-C and that are heterozygous for platelet-derived growth factor receptor alpha (Pdgfc-/-; PdgfraGFP/+) develop cerebellar hypoplasia and malformation with loss of cerebellar lobes in the posterior vermis. This phenotype is similar to those observed in Foxc1 mutant mice and in a human neuroimaging pattern called Dandy Walker malformation. Pdgfc-Pdgfra mutant mice also display ependymal denudation in the 4th ventricle and gene expression changes in cerebellar meninges, which coincide with the first visible signs of cerebellar malformation. Here we show that PDGF-C/PDGFRα signalling is a critical component in the network of molecular and cellular interactions that take place between the developing meninges and neural tissues, and which are required to build a fully functioning cerebellum.
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Richards M, Nwadozi E, Pal S, Martinsson P, Kaakinen M, Gloger M, Sjöberg E, Koltowska K, Betsholtz C, Eklund L, Nordling S, Claesson-Welsh L. Claudin5 protects the peripheral endothelial barrier in an organ and vessel type-specific manner. eLife 2022; 11:78517. [PMID: 35861713 PMCID: PMC9348850 DOI: 10.7554/elife.78517] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 07/20/2022] [Indexed: 11/30/2022] Open
Abstract
Dysfunctional and leaky blood vessels resulting from disruption of the endothelial cell (EC) barrier accompanies numerous diseases. The EC barrier is established through endothelial cell tight and adherens junctions. However, the expression pattern and precise contribution of different junctional proteins to the EC barrier is poorly understood. Here, we focus on organs with continuous endothelium to identify structural and functional in vivo characteristics of the EC barrier. Assembly of multiple single-cell RNAseq datasets into a single integrated database revealed the variability and commonalities of EC barrier patterning. Across tissues, Claudin5 exhibited diminishing expression along the arteriovenous axis, correlating with EC barrier integrity. Functional analysis identified tissue-specific differences in leakage properties and response to the leakage agonist histamine. Loss of Claudin5 enhanced histamine-induced leakage in an organotypic and vessel type-specific manner in an inducible, EC-specific, knock-out mouse. Mechanistically, Claudin5 loss left junction ultrastructure unaffected but altered its composition, with concomitant loss of zonula occludens-1 and upregulation of VE-Cadherin expression. These findings uncover the organ-specific organisation of the EC barrier and distinct importance of Claudin5 in different vascular beds, providing insights to modify EC barrier stability in a targeted, organ-specific manner.
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Sá da Bandeira D, Kilpatrick AM, Marques M, Gomez-Salazar M, Ventura T, Gonzalez ZN, Stefancova D, Rossi F, Vermeren M, Vink CS, Beltran M, Henderson NC, Jung B, van der Linden R, van de Werken HJG, van Ijcken WFJ, Betsholtz C, Forbes SJ, Cuervo H, Crisan M. PDGFRβ + cells play a dual role as hematopoietic precursors and niche cells during mouse ontogeny. Cell Rep 2022; 40:111114. [PMID: 35858557 PMCID: PMC9638014 DOI: 10.1016/j.celrep.2022.111114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/18/2022] [Accepted: 06/28/2022] [Indexed: 11/27/2022] Open
Abstract
Hematopoietic stem cell (HSC) generation in the aorta-gonad-mesonephros region requires HSC specification signals from the surrounding microenvironment. In zebrafish, PDGF-B/PDGFRβ signaling controls hematopoietic stem/progenitor cell (HSPC) generation and is required in the HSC specification niche. Little is known about murine HSPC specification in vivo and whether PDGF-B/PDGFRβ is involved. Here, we show that PDGFRβ is expressed in distinct perivascular stromal cell layers surrounding the mid-gestation dorsal aorta, and its deletion impairs hematopoiesis. We demonstrate that PDGFRβ+ cells play a dual role in murine hematopoiesis. They act in the aortic niche to support HSPCs, and in addition, PDGFRβ+ embryonic precursors give rise to a subset of HSPCs that persist into adulthood. These findings provide crucial information for the controlled production of HSPCs in vitro. PDGFRβ deletion affects hematopoietic development in the AGM in vivo The transcriptome and hematopoietic support of the PDGFRβ-KO niche are altered The osteogenic gene profile and differentiation of KO AGM MSCs are affected PDGFRβ+ early embryonic precursors contribute to EC and HSPC lineages in vivo
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Orlich MM, Diéguez-Hurtado R, Muehlfriedel R, Sothilingam V, Wolburg H, Oender CE, Woelffing P, Betsholtz C, Gaengel K, Seeliger M, Adams RH, Nordheim A. Mural Cell SRF Controls Pericyte Migration, Vessel Patterning and Blood Flow. Circ Res 2022; 131:308-327. [PMID: 35862101 PMCID: PMC9348820 DOI: 10.1161/circresaha.122.321109] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pericytes and vascular smooth muscle cells, collectively known as mural cells, are recruited through PDGFB (platelet-derived growth factor B)-PDGFRB (platelet-derived growth factor receptor beta) signaling. MCs are essential for vascular integrity, and their loss has been associated with numerous diseases. Most of this knowledge is based on studies in which MCs are insufficiently recruited or fully absent upon inducible ablation. In contrast, little is known about the physiological consequences that result from impairment of specific MC functions. Here, we characterize the role of the transcription factor SRF (serum response factor) in MCs and study its function in developmental and pathological contexts.
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Bernier-Latmani J, Mauri C, Marcone R, Renevey F, Durot S, He L, Vanlandewijck M, Maclachlan C, Davanture S, Zamboni N, Knott GW, Luther SA, Betsholtz C, Delorenzi M, Brisken C, Petrova TV. ADAMTS18 + villus tip telocytes maintain a polarized VEGFA signaling domain and fenestrations in nutrient-absorbing intestinal blood vessels. Nat Commun 2022; 13:3983. [PMID: 35810168 PMCID: PMC9271081 DOI: 10.1038/s41467-022-31571-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 06/21/2022] [Indexed: 12/17/2022] Open
Abstract
The small intestinal villus tip is the first point of contact for lumen-derived substances including nutrients and microbial products. Electron microscopy studies from the early 1970s uncovered unusual spatial organization of small intestinal villus tip blood vessels: their exterior, epithelial-facing side is fenestrated, while the side facing the villus stroma is non-fenestrated, covered by pericytes and harbors endothelial nuclei. Such organization optimizes the absorption process, however the molecular mechanisms maintaining this highly specialized structure remain unclear. Here we report that perivascular LGR5+ villus tip telocytes (VTTs) are necessary for maintenance of villus tip endothelial cell polarization and fenestration by sequestering VEGFA signaling. Mechanistically, unique VTT expression of the protease ADAMTS18 is necessary for VEGFA signaling sequestration through limiting fibronectin accumulation. Therefore, we propose a model in which LGR5+ ADAMTS18+ telocytes are necessary to maintain a “just-right” level and location of VEGFA signaling in intestinal villus blood vasculature to ensure on one hand the presence of sufficient endothelial fenestrae, while avoiding excessive leakiness of the vessels and destabilization of villus tip epithelial structures. The molecular mechanisms ensuring the specialized structure of small intestinal villus tip blood vessels are incompletely understood. Here the authors show that ADAMTS18+ telocytes maintain a “just-right” level and location of VEGFA signaling on intestinal villus blood vessels, thereby ensuring the presence of endothelial fenestrae for nutrient absorption, while avoiding excessive leakiness and destabilization of villus tip epithelial structures.
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21
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Levin A, Schwarz A, Hulkko J, He L, Sun Y, Barany P, Bruchfeld A, Herthelius M, Wennberg L, Ebefors K, Patrakka J, Betsholtz C, Nyström J, Mölne J, Hultenby K, Witasp A, Wernerson A. The role of dendrin in IgA nephropathy. Nephrol Dial Transplant 2022; 38:311-321. [PMID: 35767852 PMCID: PMC9923709 DOI: 10.1093/ndt/gfac208] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Immunoglobulin A nephropathy (IgAN) and its systemic variant IgA vasculitis (IgAV) damage the glomeruli, resulting in proteinuria, hematuria and kidney impairment. Dendrin is a podocyte-specific protein suggested to be involved in the pathogenesis of IgAN. Upon cell injury, dendrin translocates from the slit diaphragm to the nucleus, where it is suggested to induce apoptosis and cytoskeletal changes, resulting in proteinuria and accelerated disease progression in mice. Here we investigated gene and protein expression of dendrin in relation to clinical and histopathological findings to further elucidate its role in IgAN/IgAV. METHODS Glomerular gene expression was measured using microarray on 30 IgAN/IgAV patients, 5 patients with membranous nephropathy (MN) and 20 deceased kidney donors. Dendrin was spatially evaluated on kidney tissue sections by immunofluorescence (IF) staining (IgAN patients, n = 4; nephrectomized kidneys, n = 3) and semi-quantified by immunogold electron microscopy (IgAN/IgAV patients, n = 21; MN, n = 5; living kidney donors, n = 6). Histopathological grading was performed according to the Oxford and Banff classifications. Clinical data were collected at the time of biopsy and follow-up. RESULTS Dendrin mRNA levels were higher (P = .01) in IgAN patients compared with MN patients and controls and most prominently in patients with preserved kidney function and fewer chronic histopathological changes. Whereas IF staining did not differ between groups, immunoelectron microscopy revealed that a higher relative nuclear dendrin concentration in IgAN patients was associated with a slower annual progression rate and milder histopathological changes. CONCLUSION Dendrin messenger RNA levels and relative nuclear protein concentrations are increased and associated with a more benign phenotype and progression in IgAN/IgAV patients.
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22
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Lendahl U, Muhl L, Betsholtz C. Identification, discrimination and heterogeneity of fibroblasts. Nat Commun 2022; 13:3409. [PMID: 35701396 PMCID: PMC9192344 DOI: 10.1038/s41467-022-30633-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 05/04/2022] [Indexed: 12/14/2022] Open
Abstract
Fibroblasts, the principal cell type of connective tissue, secrete extracellular matrix components during tissue development, homeostasis, repair and disease. Despite this crucial role, the identification and distinction of fibroblasts from other cell types are challenging and laden with caveats. Rapid progress in single-cell transcriptomics now yields detailed molecular portraits of fibroblasts and other cell types in our bodies, which complement and enrich classical histological and immunological descriptions, improve cell class definitions and guide further studies on the functional heterogeneity of cell subtypes and states, origins and fates in physiological and pathological processes. In this review, we summarize and discuss recent advances in the understanding of fibroblast identification and heterogeneity and how they discriminate from other cell types. In this review, the authors look at how recent progress in single-cell transcriptomics complement and enrich the classical, largely morphological, portraits of fibroblasts. The detailed molecular information now available provides new insights into fibroblast identity, heterogeneity and function.
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Hultström M, Fromell K, Larsson A, Persson B, Nilsson B, Quaggin SE, Betsholtz C, Frithiof R, Lipcsey M, Jeansson M. Angiopoietin-2 Inhibition of Thrombomodulin-Mediated Anticoagulation-A Novel Mechanism That May Contribute to Hypercoagulation in Critically Ill COVID-19 Patients. Biomedicines 2022; 10:1333. [PMID: 35740360 PMCID: PMC9220312 DOI: 10.3390/biomedicines10061333] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/23/2022] [Accepted: 06/02/2022] [Indexed: 01/08/2023] Open
Abstract
Hypercoagulation and endothelial dysfunction play central roles in severe forms of COVID-19 infections, but the molecular mechanisms involved are unclear. Increased plasma levels of the inflammatory cytokine and TIE2 receptor antagonist Angiopoietin-2 were reported in severely ill COVID-19 patients. In vitro experiments suggest that Angiopoietin-2 bind and inhibits thrombomodulin. Thrombomodulin is expressed on the luminal surface of endothelial cells where it is an important member of the intrinsic anticoagulant pathway through activation of protein C. Using clinical data, mouse models, and in vitro assays, we tested if Angiopoietin-2 plays a causal role in COVID-19-associated hypercoagulation through direct inhibition of thrombin/thrombomodulin-mediated physiological anticoagulation. Angiopoietin-2 was measured in 61 patients at admission, and after 10 days in the 40 patients remaining in the ICU. We found that Angiopoietin-2 levels were increased in COVID-19 patients in correlation with disease severity, hypercoagulation, and mortality. In support of a direct effect of Angiopoietin-2 on coagulation, we found that injected Angiopoietin-2 in mice associated to thrombomodulin and resulted in a shortened tail bleeding time, decreased circulating levels of activated protein C, and increased plasma thrombin/antithrombin complexes. Conversely, bleeding time was increased in endothelial-specific Angiopoietin-2 knockout mice, while knockout of Tie2 had no effect on tail bleeding. Using in vitro assays, we found that Angiopoietin-2 inhibited thrombomodulin-mediated anticoagulation and protein C activation in human donor plasma. Our data suggest a novel in vivo mechanism for Angiopoietin-2 in COVID-19-associated hypercoagulation, implicating that Angiopoietin-2 inhibitors may be effective in the treatment of hypercoagulation in severe COVID-19 infection.
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Shoda J, Tanaka S, Etori K, Hattori K, Kasuya T, Ikeda K, Maezawa Y, Suto A, Suzuki K, Nakamura J, Maezawa Y, Takemoto M, Betsholtz C, Yokote K, Ohtori S, Nakajima H. Semaphorin 3G exacerbates joint inflammation through the accumulation and proliferation of macrophages in the synovium. Arthritis Res Ther 2022; 24:134. [PMID: 35659346 PMCID: PMC9166515 DOI: 10.1186/s13075-022-02817-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 05/17/2022] [Indexed: 02/07/2023] Open
Abstract
Objectives Methotrexate (MTX) is an anchor drug for the treatment of rheumatoid arthritis (RA). However, the precise mechanisms by which MTX stalls RA progression and alleviates the ensuing disease effects remain unknown. The aim of the present study was to identify novel therapeutic target molecules, the expression patterns of which are affected by MTX in patients with RA. Methods CD4+ T cells from 28 treatment-naïve patients with RA before and 3 months after the initiation of MTX treatment were subjected to DNA microarray analyses. The expression levels of semaphorin 3G, a differentially expressed gene, and its receptor, neuropilin-2, were evaluated in the RA synovium and collagen-induced arthritis synovium. Collagen-induced arthritis and collagen antibody-induced arthritis were induced in semaphorin3G-deficient mice and control mice, and the clinical score, histological score, and serum cytokines were assessed. The migration and proliferation of semaphorin 3G-stimulated bone marrow-derived macrophages were analyzed in vitro. The effect of local semaphorin 3G administration on the clinical score and number of infiltrating macrophages during collagen antibody-induced arthritis was evaluated. Results Semaphorin 3G expression in CD4+ T cells was downregulated by MTX treatment in RA patients. It was determined that semaphorin 3G is expressed in RA but not in the osteoarthritis synovium; its receptor neuropilin-2 is primarily expressed on activated macrophages. Semaphorin3G deficiency ameliorated collagen-induced arthritis and collagen antibody-induced arthritis. Semaphorin 3G stimulation enhanced the migration and proliferation of bone marrow-derived macrophages. Local administration of semaphorin 3G deteriorated collagen antibody-induced arthritis and increased the number of infiltrating macrophages. Conclusions Upregulation of semaphorin 3G in the RA synovium is a novel mechanism that exacerbates joint inflammation, leading to further deterioration, through macrophage accumulation.
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Ando K, Tong L, Peng D, Vázquez-Liébanas E, Chiyoda H, He L, Liu J, Kawakami K, Mochizuki N, Fukuhara S, Grutzendler J, Betsholtz C. KCNJ8/ABCC9-containing K-ATP channel modulates brain vascular smooth muscle development and neurovascular coupling. Dev Cell 2022; 57:1383-1399.e7. [PMID: 35588738 DOI: 10.1016/j.devcel.2022.04.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 12/22/2021] [Accepted: 04/26/2022] [Indexed: 12/30/2022]
Abstract
Loss- or gain-of-function mutations in ATP-sensitive potassium channel (K-ATP)-encoding genes, KCNJ8 and ABCC9, cause human central nervous system disorders with unknown pathogenesis. Here, using mice, zebrafish, and cell culture models, we investigated cellular and molecular causes of brain dysfunctions derived from altered K-ATP channel function. We show that genetic/chemical inhibition or activation of KCNJ8/ABCC9-containing K-ATP channel function leads to brain-selective suppression or promotion of arterial/arteriolar vascular smooth muscle cell (VSMC) differentiation, respectively. We further show that brain VSMCs develop from KCNJ8/ABCC9-containing K-ATP channel-expressing mural cell progenitor and that K-ATP channel cell autonomously regulates VSMC differentiation through modulation of intracellular Ca2+ oscillation via voltage-dependent calcium channels. Consistent with defective VSMC development, Kcnj8 knockout mice showed deficiency in vasoconstrictive capacity and neuronal-evoked vasodilation leading to local hyperemia. Our results demonstrate a role for KCNJ8/ABCC9-containing K-ATP channels in the differentiation of brain VSMC, which in turn is necessary for fine-tuning of cerebral blood flow.
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