Biology subjects

Lendahl, U.

Publications and source records attributed to Lendahl, U..

3 recordsLinked to original sources

bioRxiv2020

Neural Plate Targeting by in Utero NanoinjEction (NEPTUNE) reveals a role for Sptbn2 in neurulation and abdominal wall closure

Gene variants associated with disease are efficiently identified with whole genome sequencing or GWAS, but validation in vivo lags behind. We developed NEPTUNE (neural plate targeting by in utero nanoinjection), to rapidly and flexibly introduce gene expression-modifying viruses to the embryonic murine neural plate prior to neurulation, to target the future adult nervous system. Stable integration in >95% of cells in the brain enabled long-term gain- or loss-of-function, and conditional expression was achieved using mini-promotors for cell types of interest. Using NEPTUNE, we silenced Sptbn2, a gene associated with Spinocerebellar ataxia type 5 (SCA5) in humans. Silencing of Sptbn2 induced severe neural tube defects and embryo resorption, suggesting that SPTBN2 in-frame and missense deletions in SCA5 reflect hypomorphic or neomorphic functions, not loss of function. In conclusion, NEPTUNE offers a novel, rapid and cost-effective technique to test gene function in brain development, and can reveal loss of function phenotypes incompatible with life.

developmental biology↗

bioRxiv2020

Pericyte-specific vascular expression of SARS-CoV-2 receptor ACE2 - implications for microvascular inflammation and hypercoagulopathy in COVID-19 patients

Accumulating clinical observations implicate vascular inflammation as an underlying cause of coagulopathy in severely ill COVID-19 patients and it was recently suggested that SARS-CoV-2 virus particles infect endothelial cells. Here, we show that endothelial cells do not express angiotensin-converting enzyme-2 (ACE2), the SARS-CoV-2 receptor. Instead, pericytes and microvascular smooth muscle cells express ACE2 in an organotypic manner. Pericyte deficiency leads to increased endothelial expression and release of Von Willebrand factor and intravascular platelet and fibrin aggregation, suggesting that pericytes limit endothelial pro-thrombotic responses. That pericytes and not endothelial cells express ACE2 may provide important clues to the pathology of COVID-19, as pericytes are normally shielded behind an endothelial barrier and may get infected only when this barrier is compromised by COVID-19 risk factors.

pathology↗

bioRxiv2019

DoUble resin Casting micro computed Tomography (DUCT) reveals biliary and vascular pathology in a mouse model of Alagille syndrome

BACKGROUND AND AIMSAlagille syndrome, like several other liver diseases, is characterized by malformation of lumenized structures, such as the circulatory or biliary systems. Liver architecture has typically been studied through 2D sections and, more recently, using thick tissue sections combined with immunofluorescence. We aimed to develop a robust method to image, digitalize and quantify 3D architecture of the biliary and vascular systems in tandem. METHODSThe biliary and portal vein trees of the mouse liver were injected with Microfil resin, followed by microCT scanning. Tomographic data was segmented and analyzed using a MATLAB script we wrote to investigate length, volume, tortuosity, branching, and the relation between the vascular and biliary systems. Double resin casting micro computed tomography (DUCT) was applied to a mouse model for Alagille syndrome (Jag1Ndr/Ndr mice), in which the biliary system is absent at postnatal stages, but regenerates by adulthood. Phenotypes discovered using DUCT were validated with cumbersome consecutive liver sections from mouse and human liver including patients with Alagille syndrome. RESULTSDUCT revealed tortuous bile ducts either placed further from portal veins, or ectopically traversing the parenchyma and connecting two portal areas, in Jag1Ndr/Ndr mice. Furthermore, bile ducts either ended abruptly, or branched independently of portal vein branching, with bifurcations placed hilar or peripheral to portal vein branches. The branching defects, parenchymal bile ducts, and blunt endings were confirmed in patient samples. CONCLUSIONDUCT is a powerful technique, which provides computerized 3D reconstruction of casted networks. It exposes and quantifies previously unknown vascular and biliary phenotypes in mouse models, revealing new phenotypes in patients. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/848481v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@1565121org.highwire.dtl.DTLVardef@1e86cfcorg.highwire.dtl.DTLVardef@4b4cc3org.highwire.dtl.DTLVardef@19cb20e_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗