Biology subjects

Nordling, S.

Publications and source records attributed to Nordling, S..

4 recordsLinked to original sources

bioRxiv2022

Claudin5 protects the peripheral endothelial barrier in an organ and vessel type-specific manner

The pathogenesis of numerous diseases is characterised by disruption of the junctions that form the endothelial cell (EC) barrier, the composition of which may differ greatly between organs. However, the expression level variability and precise contribution of different junctional proteins 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 in EC barrier patterning. Across tissues Claudin5 exhibited diminishing expression along the arteriovenous axis, which correlates with EC barrier integrity. Functional analysis identified tissue-specific differences in leakage patterning and response to agonist-induced leakage. We uncover that Claudin5 loss enhances agonist-induced leakage in an organotypic, vessel type-specific and size-selective manner in an inducible, EC-specific, knock-out mouse. Mechanistically, Claudin5 loss induces no change in junction ultrastructure but alters composition, with concomitant loss of zonula occludens-1 (ZO-1) expression and upregulation of VE-Cadherin. These findings uncover the organ-specific organisation of the EC barrier and distinct importance of Claudin5 in different vascular beds and will aid our ability to modify EC barrier stability in a targeted, organ-specific manner.

cell biology↗

bioRxiv2020

A molecular map of lymph node blood vascular endothelium at single cell resolution

Blood vascular endothelial cells (BECs) control the immune response by regulating immune cell recruitment, metabolite exchange and blood flow in lymphoid tissues. However, the diversity of BEC and their origins during immune angiogenesis remain poorly understood. Here we profile transcriptomes of BEC from mouse peripheral lymph nodes and map key phenotypes to the vasculature. Our analysis identifies multiple novel subsets including a venous population whose gene signature predicts an unexpectedly selective role in myeloid cell (vs lymphocyte) recruitment to the medulla, confirmed by 2 photon videomicroscopy. We define five phenotypes of capillary lining BEC including a capillary resident regenerative population (CRP) that displays stem cell and migratory gene signatures and contributes to homeostatic BEC turnover and to vascular neogenesis after immunization. Trajectory analyses reveal retention of developmental programs along a progression of cellular phenotypes from CRP to mature venous and arterial BEC subsets. Overall, our single cell atlas provides a molecular blueprint of the lymph node blood vasculature and defines subset specialization for immune cell recruitment and vascular homeostasis.

immunology↗

bioRxiv2020

A single-cell transcriptional roadmap of the mouse and human lymph node lymphatic vasculature

Single-cell transcriptomics promises to revolutionize our understanding of the vasculature. Emerging computational methods applied to high dimensional single cell data allow integration of results between samples and species, and illuminate the diversity and underlying developmental and architectural organization of cell populations. Here, we illustrate these methods in analysis of mouse lymph node (LN) lymphatic endothelial cells (LEC) at single cell resolution. Clustering identifies five well-delineated subsets, including two medullary sinus subsets not recognized previously as distinct. Nearest neighbor alignments in trajectory space position the major subsets in a sequence that recapitulates known and suggests novel features of LN lymphatic organization, providing a transcriptional map of the lymphatic endothelial niches and of the transitions between them. Differences in gene expression reveal specialized programs for (1) subcapsular ceiling endothelial interactions with the capsule connective tissue and cells, (2) subcapsular floor regulation of lymph borne cell entry into the LN parenchyma and antigen presentation, and (3) medullary subset specialization for pathogen interactions and LN remodeling. LEC of the subcapsular sinus floor and medulla, which represent major sites of cell entry and exit from the LN parenchyma respectively, respond robustly to oxazolone inflammation challenge with enriched signaling pathways that converge on both innate and adaptive immune responses. Integration of mouse and human single-cell profiles reveals a conserved cross-species pattern of lymphatic vascular niches and gene expression, as well as specialized human subsets and genes unique to each species. The examples provided demonstrate the power of single-cell analysis in elucidating endothelial cell heterogeneity, vascular organization and endothelial cell responses. We discuss the findings from the perspective of LEC functions in relation to niche formations in the unique stromal and highly immunological environment of the LN. Highlights Computational alignments ("trajectories") predict LN LEC organization in situ, revealing a continuum of phenotypes punctuated by specialized clusters Multiple intermediate phenotypes suggest LEC malleability Gene profiles define niche-specific functional specialization Medullary sinus LECs are comprised of Ptx3-LECs and Marco-LECs O_LIDistinct mechanisms for pathogen interactions and matrix modeling C_LIO_LIPtx3-LECs: paracortical and central medullary sinuses near hilus; enriched for genes driving lymphangiogenic responses and lymphocyte egress C_LIO_LIMarco-LECs: peri-follicular medullary sinuses; macrophage-associated genes, complement and coagulation cascade C_LI Niche-specific responses to inflammation O_LIIFN gene responses in SCS floor and medullary sinus LECs C_LIO_LISuppression of LEC identity genes in responding subsets C_LI Conserved and unique LEC subsets and gene programs across species O_LICore subsets common to mouse and human C_LIO_LIGreater diversity of subsets and intermediates in human LN LECs C_LI

systems biology↗

bioRxiv2018

Detection of breast cancer lymph node metastases in frozen sections with a point-of-care low-cost microscope scanner

BackgroundDetection of lymph node metastases is essential in breast cancer diagnostics and staging, affecting treatment and prognosis. Intraoperative microscopy analysis of sentinel lymph node frozen sections is standard for detection of axillary metastases, but requires access to a pathologist for sample analysis. Remote analysis of digitized samples is an alternative solution, but is limited by the requirement for high-end slide scanning equipment.\n\nObjectiveTo determine whether the image quality achievable with a low-cost, miniature digital microscope scanner is sufficient for detection of metastases in breast cancer lymph node frozen sections.\n\nMethodsLymph node frozen sections from 79 breast cancer patients were digitized using a prototype miniature microscope scanner and a high-end slide scanner. Images were independently reviewed by two pathologists and results compared between devices with conventional light microscopy analysis as ground truth.\n\nResultsDetection of metastases in the images acquired with the miniature scanner yielded an overall sensitivity of 91 % and specificity of 99 % and showed strong agreement when compared to light microscopy (k = 0.91). Strong agreement was also observed when results were compared to results from the high-end slide scanner (k = 0.94). A majority of discrepant cases were micrometastases and sections of which no anticytokeratin staining was available.\n\nConclusionAccuracy of detection of metastatic cells in breast cancer sentinel lymph node frozen sections by visual analysis of samples digitized using low-cost, point-of-care microscopy is comparable to analysis of digital samples scanned using a high-end, whole slide scanner. This technique could potentially provide a workflow for digital diagnostics in resource-limited settings, facilitate sample analysis at the point-of-care and reduce the need for trained experts on-site during surgical procedures.

pathology↗