| 1. |
- Keller, Annika, et al.
(författare)
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Mutations in the gene encoding PDGF-B cause brain calcifications in humans and mice
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:9, s. 1077-
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Tidskriftsartikel (refereegranskat)abstract
- Calcifications in the basal ganglia are a common incidental finding and are sometimes inherited as an autosomal dominant trait ( idiopathic basal ganglia calcification (IBGC)). Recently, mutations in the PDGFRB gene coding for the platelet-derived growth factor receptor beta (PDGF-R beta) were linked to IBGC. Here we identify six families of different ancestry with nonsense and missense mutations in the gene encoding PDGF-B, the main ligand for PDGF-R beta. We also show that mice carrying hypomorphic Pdgfb alleles develop brain calcifications that show age-related expansion. The occurrence of these calcium depositions depends on the loss of endothelial PDGF-B and correlates with the degree of pericyte and blood-brain barrier deficiency. Thus, our data present a clear link between Pdgfb mutations and brain calcifications in mice, as well as between PDGFB mutations and IBGC in humans.
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| 2. |
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| 3. |
- He, Liqun, et al.
(författare)
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Analysis of the brain mural cell transcriptome
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Pericytes, the mural cells of blood microvessels, regulate microvascular development and function and have been implicated in many brain diseases. However, due to a paucity of defining markers, pericyte identification and functional characterization remain ambiguous and data interpretation problematic. In mice carrying two transgenic reporters, Pdgfrb-eGFP and NG2-DsRed, we found that double-positive cells were vascular mural cells, while the single reporters marked additional, but non-overlapping, neuroglial cells. Double-positive cells were isolated by fluorescence-activated cell sorting (FACS) and analyzed by RNA sequencing. To reveal defining patterns of mural cell transcripts, we compared the RNA sequencing data with data from four previously published studies. The meta-analysis provided a conservative catalogue of 260 brain mural cell-enriched gene transcripts. We validated pericyte-specific expression of two novel markers, vitronectin (Vtn) and interferon-induced transmembrane protein 1 (Ifitm1), using fluorescent in situ hybridization and immunohistochemistry. We further analyzed signaling pathways and interaction networks of the pericyte-enriched genes in silico. This work provides novel insight into the molecular composition of brain mural cells. The reported gene catalogue facilitates identification of brain pericytes by providing numerous new candidate marker genes and is a rich source for new hypotheses for future studies of brain mural cell physiology and pathophysiology.
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| 4. |
- He, Liqun, et al.
(författare)
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Single-cell RNA sequencing of mouse brain and lung vascular and vessel-associated cell types
- 2018
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Ingår i: Scientific Data. - : NATURE PUBLISHING GROUP. - 2052-4463. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Vascular diseases are major causes of death, yet our understanding of the cellular constituents of blood vessels, including how differences in their gene expression profiles create diversity in vascular structure and function, is limited. In this paper, we describe a single-cell RNA sequencing (scRNA-seq) dataset that defines vascular and vessel-associated cell types and subtypes in mouse brain and lung. The dataset contains 3,436 single cell transcriptomes from mouse brain, which formed 15 distinct clusters corresponding to cell (sub) types, and another 1,504 single cell transcriptomes from mouse lung, which formed 17 cell clusters. In order to allow user-friendly access to our data, we constructed a searchable database (http://betsholtzlab.org/VascularSingleCells/database.html). Our dataset constitutes a comprehensive molecular atlas of vascular and vessel-associated cell types in the mouse brain and lung, and as such provides a strong foundation for future studies of vascular development and diseases.
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| 5. |
- Henderson, Neil C., et al.
(författare)
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Targeting of alpha(v) integrin identifies a core molecular pathway that regulates fibrosis in several organs
- 2013
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 19:12, s. 1617-1624
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Tidskriftsartikel (refereegranskat)abstract
- Myofibroblasts are the major source of extracellular matrix components that accumulate during tissue fibrosis, and hepatic stellate cells (HSCs) are believed to be the major source of myofibroblasts in the liver. To date, robust systems to genetically manipulate these cells have not been developed. We report that Cre under control of the promoter of Pdgfrb (Pdgfrb-Cre) inactivates loxP-flanked genes in mouse HSCs with high efficiency. We used this system to delete the gene encoding alpha(v) integrin subunit because various alpha(v)-containing integrins have been suggested as central mediators of fibrosis in multiple organs. Such depletion protected mice from carbon tetrachloride-induced hepatic fibrosis, whereas global loss of beta(3), beta(5) or beta(6) integrins or conditional loss of beta(8) integrins in HSCs did not. We also found that Pdgfrb-Cre effectively targeted myofibroblasts in multiple organs, and depletion of the alpha(v) integrin subunit using this system was protective in other models of organ fibrosis, including pulmonary and renal fibrosis. Pharmacological blockade of alpha(v)-containing integrins by a small molecule (CWHM 12) attenuated both liver and lung fibrosis, including in a therapeutic manner. These data identify a core pathway that regulates fibrosis and suggest that pharmacological targeting of all alpha(v) integrins may have clinical utility in the treatment of patients with a broad range of fibrotic diseases.
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| 6. |
- Henshall, Tanya L, et al.
(författare)
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Notch3 Is Necessary for Blood Vessel Integrity in the Central Nervous System
- 2015
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - 1079-5642 .- 1524-4636. ; 35:2, s. 409-420
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Vascular smooth muscle cells (VSMC) are important for contraction, blood flow distribution, and regulation of blood vessel diameter, but to what extent they contribute to the integrity of blood vessels and blood-brain barrier function is less well understood. In this report, we explored the impact of the loss of VSMC in the Notch3(-/-) mouse on blood vessel integrity in the central nervous system.APPROACH AND RESULTS: Notch3(-/-) mice showed focal disruptions of the blood-brain barrier demonstrated by extravasation of tracers and accompanied by fibrin deposition in the retinal vasculature. This blood-brain barrier leakage was accompanied by a regionalized and patchy loss of VSMC, with VSMC gaps predominantly in arterial resistance vessels of larger caliber. The loss of VSMC appeared to be caused by progressive degeneration of VSMC resulting in a gradual loss of VSMC marker expression and a progressive acquisition of an aberrant VSMC phenotype closer to the gaps, followed by enhanced apoptosis and cellular disintegration in the gaps. Arterial VSMC were the only mural cell type that was morphologically affected, despite Notch3 being expressed also in pericytes. Transcriptome analysis of isolated brain microvessels revealed gene expression changes in Notch3(-/-) mice consistent with loss of arterial VSMC and presumably secondary transcriptional changes were observed in endothelial genes, which may explain the compromised vascular integrity.CONCLUSIONS: We demonstrate that Notch3 is important for survival of VSMC, and reveal a critical role for Notch3 and VSMC in blood vessel integrity and blood-brain barrier function in the mammalian vasculature.
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| 7. |
- Jung, Bongnam, et al.
(författare)
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Visualization of vascular mural cells in developing brain using genetically labeled transgenic reporter mice
- 2018
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE PUBLICATIONS INC. - 0271-678X .- 1559-7016. ; 38:3, s. 456-468
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Tidskriftsartikel (refereegranskat)abstract
- The establishment of a fully functional blood vascular system requires elaborate angiogenic and vascular maturation events in order to fulfill organ-specific anatomical and physiological needs. Although vascular mural cells, i.e. pericytes and vascular smooth muscle cells, are known to play fundamental roles during these processes, their characteristics during vascular development remain incompletely understood. In this report, we utilized transgenic reporter mice in which mural cells are genetically labeled to examine developing vascular mural cells in the central nervous system (CNS). We found platelet-derived growth factor receptor beta gene (Pdgfrb)-driven EGFP reporter expression as a suitable marker for vascular mural cells at the earliest stages of mouse brain vascularization. Furthermore, the combination of Pdgfrb and NG2 gene (Cspg4) driven reporter expression increased the specificity of brain vascular mural cell labeling at later stages. The expression of other known pericyte markers revealed time-,region-and marker-specific patterns, suggesting heterogeneity in mural cell maturation. We conclude that transgenic reporter mice provide an important tool to explore the development of CNS pericytes in health and disease.
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| 8. |
- Muhl, Lars, et al.
(författare)
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A single-cell transcriptomic inventory of murine smooth muscle cells
- 2022
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Ingår i: Developmental Cell. - : Elsevier. - 1534-5807 .- 1878-1551. ; 57:20, s. 2426-
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Tidskriftsartikel (refereegranskat)abstract
- Smooth muscle cells (SMCs) execute important physiological functions in numerous vital organ systems, including the vascular, gastrointestinal, respiratory, and urogenital tracts. SMC differ morphologically and functionally at these different anatomical locations, but the molecular underpinnings of the differences remain poorly understood. Here, using deep single-cell RNA sequencing combined with in situ gene and pro-tein expression analysis in four murine organs-heart, aorta, lung, and colon-we identify a molecular basis for high-level differences among vascular, visceral, and airway SMC, as well as more subtle differences between, for example, SMC in elastic and muscular arteries and zonation of elastic artery SMC along the direction of blood flow. Arterial SMC exhibit extensive organotypic heterogeneity, whereas venous SMC are similar across organs. We further identify a specific SMC subtype within the pulmonary vasculature. This comparative SMC cross-organ resource offers insight into SMC subtypes and their specific functions.
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| 9. |
- Muhl, Lars, et al.
(författare)
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Single-cell analysis uncovers fibroblast heterogeneity and criteria for fibroblast and mural cell identification and discrimination
- 2020
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Many important cell types in adult vertebrates have a mesenchymal origin, including fibroblasts and vascular mural cells. Although their biological importance is undisputed, the level of mesenchymal cell heterogeneity within and between organs, while appreciated, has not been analyzed in detail. Here, we compare single-cell transcriptional profiles of fibroblasts and vascular mural cells across four murine muscular organs: heart, skeletal muscle, intestine and bladder. We reveal gene expression signatures that demarcate fibroblasts from mural cells and provide molecular signatures for cell subtype identification. We observe striking inter- and intra-organ heterogeneity amongst the fibroblasts, primarily reflecting differences in the expression of extracellular matrix components. Fibroblast subtypes localize to discrete anatomical positions offering novel predictions about physiological function(s) and regulatory signaling circuits. Our data shed new light on the diversity of poorly defined classes of cells and provide a foundation for improved understanding of their roles in physiological and pathological processes. To define and distinguish fibroblasts from vascular mural cells have remained challenging. Here, using single-cell RNA sequencing and tissue imaging, the authors provide a molecular basis for cell type classification and reveal inter- and intra-organ diversity of these cell types.
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| 10. |
- Nishibori, Yukino, et al.
(författare)
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Glcci1 Deficiency Leads to Proteinuria
- 2011
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Ingår i: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 22:11, s. 2037-2046
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Tidskriftsartikel (refereegranskat)abstract
- Unbiased transcriptome profiling and functional genomics approaches identified glucocorticoid-induced transcript 1 (GLCCI1) as being a transcript highly specific for the glomerulus, but its role in glomerular development and disease is unknown. Here, we report that mouse glomeruli express far greater amounts of Glcci1 protein compared with the rest of the kidney. RT-PCR and Western blotting demonstrated that mouse glomerular Glcci1 is approximately 60 kD and localizes to the cytoplasm of podocytes in mature glomeruli. In the fetal kidney, intense Glcci1 expression occurs at the capillary-loop stage of glomerular development. Using gene knockdown in zebrafish with morpholinos, morphants lacking Glcci1 function had collapsed glomeruli with foot-process effacement. Permeability studies of the glomerular filtration barrier in these zebrafish morphants demonstrated a disruption of the selective glomerular permeability filter. Taken together, these data suggest that Glcci1 promotes the normal development and maintenance of podocyte structure and function.
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| 11. |
- Raschperger, Elisabeth, et al.
(författare)
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CLMP, a novel member of the CTX family and a new component of epithelial tight junctions
- 2004
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 279:1, s. 796-804
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Tidskriftsartikel (refereegranskat)abstract
- The CTX family is a growing group of type I transmembrane proteins within the immunoglobulin superfamily (IgSF). They localize to junctional complexes between endothelial and epithelial cells and seem to participate in cell-cell adhesion and transmigration of leukocytes. Here, we report the identification of a new member of the CTX family. This protein, which was designated CLMP (coxsackie- and adenovirus receptor-like membrane protein), is composed of 373 amino acids including an extracellular part containing a V- and a C2-type domain, a transmembrane region and a cytoplasmic tail. CLMP mRNA was detected in a variety of both human and mouse tissues and cell lines. The protein migrated with an Mr of around 48 on SDS-PAGE and was predominantly expressed in epithelial cells within different tissues. In cultured epithelial cells, CLMP was detected in areas of cell-cell contacts. When exogenously expressed in polarized MDCK cells, CLMP was restricted to the subapical area of the lateral cell surface, where it co-localized with the tight junction markers ZO-1 and occludin. Also endogenous CLMP showed association with tight junctions, as analyzed in polarized human CACO-2 cells. This suggested a role for CLMP in cell-cell adhesion and indeed, overexpressed CLMP induced aggregation of non-polarized CHO cells. Furthermore, CLMP-expressing MDCK cells showed significantly increased transepithelial resistance, indicating a role for CLMP in junctional barrier function. Thus, we conclude that CLMP is a novel cell-cell adhesion molecule and a new component of epithelial tight junctions. We also suggest, based on phylogenetic studies, that CLMP, CAR, ESAM, and BT-IgSF form a new group of proteins within the CTX family.
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| 12. |
- Raschperger, Elisabeth
(författare)
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Studies on CAR and CLMP : two proteins of epithelial tight junctions
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tight junctions are important structures for the function of epithelial cells. They are composed of multi-protein complexes that connect the plasma membranes of two adjacent epithelial cells to each other and function as paracellular barriers, which regulate flux of ions, solutes, proteins and cells across the epithelium. Classical transmembrane components of tight junctions include the tetra- membrane- spann i ng proteins claudins and occludin, which are involved in the formation of these junction complexes. In this thesis, a newly identified group of tight junction proteins is described. These proteins belong to the cortical thymocyte marker in Xenopus (CTX)-subfamily, which belongs to the larger immunoglobulin superfamily of cell adhesion molecules. All CTX-like proteins are type-1 single spanning transmembrane proteins that are composed of two extracellular immunoglobulin loops and an intracellular tail containing a PDZ-domain binding motif, which is used for interactions with PDZ-domain containing proteins that serve as scaffolds, anchoring the transmembrane components of tight junctions to the cytoskeleton. CTX-like proteins mediate cell-cell adhesion and have the capacity to increase transepithelial electrical resistance (TER) across epithelial cells, which suggests a role in barrier function. One member of the CTX-family has been of particular interest: the coxsackie and adenovirus receptor (CAR). CAR was originally identified as a virus receptor and has, as such, been in focus in various adenovirus-based gene transfer and gene therapy studies. Its in vitro properties as being a cell adhesion molecule, expressed at epithelial tight junctions, have also been analyzed. The physiological role of CAR in vivo, however, is less clear. The major aims of these studies were to determine the function of CAR and a newly identified member of the CTX-family, CAR-like membrane protein (CLMP), in adult tissues and during embryonic development. The ligand-of-numb protein-X (LNX) was identified as a novel interacting partner of CAR and co-localized with CAR at cell-cell contacts in epithelial cells. Moreover, CAR was essential for the recruitment of LNX to this sub-cellular localization. In the adult mouse, CAR was predominantly expressed in epithelial cells, where it localized to tight junctions. The intracellular tail of CAR was essential for correct tight junction localization in vivo. A positive correlation between CAR expression and tight junction maturity was found in epithelial cells lining different segments of the tubules in the kidneys. This suggested a role for CAR in regulating permeability and tissue homeostasis, which was further supported by results from studies of the effect of CAR knockdown during zebrafish development. Fish embryos lacking CAR expression in all cells and tissues developed abnormalities that were associated with kidney failure, such as pericardial and body edema and formation of renal cysts. These studies showed that CAR is essential for proper kidney development and function and thus uncovered a novel function for CAR, which had not been detected in mouse embryos lacking CAR expression. CLMP, which was identified through computer-based database searches, was similarly to CAR, expressed in epithelial cells, where it localized to tight junctions. Functional studies showed that CLMP could mediate cell-cell adhesion and increase TER across epithelial cells in culture. In conclusion, the findings presented in this thesis expand our knowledge of the physiological function of CAR and give new insights into the complexity of the CTX-subfamily group of proteins.
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| 13. |
- Sollerbrant, Kerstin, et al.
(författare)
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The Coxsackievirus and adenovirus receptor (CAR) forms a complex with the PDZ domain-containing protein ligand-of-numb protein-X (LNX)
- 2003
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 278:9, s. 7439-7444
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Tidskriftsartikel (refereegranskat)abstract
- The Coxsackievirus and adenovirus receptor (CAR) functions as a virus receptor, but its primary biological function is unknown. A yeast two-hybrid screen was used to identify Ligand-of-Numb protein-X (LNX) as a binding partner to the intracellular tail of CAR. LNX harbors several protein-protein interacting domains, including four PDZ domains, and was previously shown to bind to and regulate the expression level of the cell-fate determinant Numb. CAR was able to bind LNX both in vivo and in vitro. Efficient binding to LNX required not only the consensus PDZ domain binding motif in the C terminus of CAR but also upstream sequences. The CAR binding region in LNX was mapped to the second PDZ domain. CAR and LNX were also shown to colocalize in vivo in mammalian cells. We speculate that CAR and LNX are part of a larger protein complex that might have important functions at discrete subcellular localizations in the cell.
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