Dedifferenzierung renaler Endothelzellen zu einer neuen und dynamischen Zellpopulation im renalen subkapsulären Raum

TY - ABST

T1 - Dedifferenzierung renaler Endothelzellen zu einer neuen und dynamischen Zellpopulation im renalen subkapsulären Raum

AU - Sardella, Donato

AU - Pohl, Layla

AU - Kidmose, Hanne

AU - Bordoni, Luca

AU - Schiessl, Ina Maria

PY - 2021

Y1 - 2021

N2 - Endothelial cells (ECs) may undergo endothelial-to-mesenchymal-transition (EndMT), which plays pivotal roles in development and disease processes, such as tissue fibrosis. Since the renal interstitial compartment is difficult to study in vivo, the prevalence and dynamics of EndMT in the kidney are incompletely understood. Here we used serial intravital 2-photon microscopy of transgenic mouse kidneys to track EndMT in control and after laser-induced renal tissue ablation.Low-dose Tamoxifen-induced Cdh5-CreERT2-Confetti mice (n=5) were used to identify individual ECs through the expression of 2 out of the 4 fluorescent proteins membrane-CFP, nuclear-GFP, cytosolic-YFP or –RFP, resulting in random labeling with 1 out of 10 possible color-combinations. For non-invasive serial 2-photon imaging of the living kidney, an abdominal imaging window was implanted. Mapping of the attached kidney surface created an atlas for long-term navigation and repeated imaging of the same kidney regions. Renal tissue ablation (100 um diameter) was achieved by focused high laser power. Control and injured fields of view (FOV) were repeatedly scanned for 5-7 days. Baseline intravital imaging of Cdh5-CreERT2-Confetti mice, revealed a morphologically distinct Cdh5-lineage (Confetti-positive) cell population with flattened cellular body (termed flat cells) within the renal subcapsular space (SCS). Flat cells either maintained a structural continuum with resident peritubular ECs or appeared isolated in the SCS. While mostly static, few flat cells displayed a remarkable mobility and randomly migrated the SCS in control (mean distance=81.69±0.41 μm, velocity=1.15±0.17 μm/h, n=32). Following injury, flat cells showed targeted migration towards the injury site while migrating longer distances (96.73±5.7 μm, n=36, p=.02) and at higher speed (1.7±0.19 μm/h, n=36, p=.02) than in control and emitting filopodia-like structures, reaching towards the injury site. In addition to pre-existing flat cells, we further observed the formation of more flat cells through the transitioning of several resident ECs to a flattened phenotype followed by migration. Histological stainings on perfusion-fixed thick kidney samples revealed that flat cells in the SCS expressed the mesenchymal markers αSMA and vimentin, suggestive of EndMT.Our data identified a novel and dynamic cell population in the SCS, which derives from renal peritubular ECs undergoing EndMT and which participates in renal cell remodeling after acute renal injury.

AB - Endothelial cells (ECs) may undergo endothelial-to-mesenchymal-transition (EndMT), which plays pivotal roles in development and disease processes, such as tissue fibrosis. Since the renal interstitial compartment is difficult to study in vivo, the prevalence and dynamics of EndMT in the kidney are incompletely understood. Here we used serial intravital 2-photon microscopy of transgenic mouse kidneys to track EndMT in control and after laser-induced renal tissue ablation.Low-dose Tamoxifen-induced Cdh5-CreERT2-Confetti mice (n=5) were used to identify individual ECs through the expression of 2 out of the 4 fluorescent proteins membrane-CFP, nuclear-GFP, cytosolic-YFP or –RFP, resulting in random labeling with 1 out of 10 possible color-combinations. For non-invasive serial 2-photon imaging of the living kidney, an abdominal imaging window was implanted. Mapping of the attached kidney surface created an atlas for long-term navigation and repeated imaging of the same kidney regions. Renal tissue ablation (100 um diameter) was achieved by focused high laser power. Control and injured fields of view (FOV) were repeatedly scanned for 5-7 days. Baseline intravital imaging of Cdh5-CreERT2-Confetti mice, revealed a morphologically distinct Cdh5-lineage (Confetti-positive) cell population with flattened cellular body (termed flat cells) within the renal subcapsular space (SCS). Flat cells either maintained a structural continuum with resident peritubular ECs or appeared isolated in the SCS. While mostly static, few flat cells displayed a remarkable mobility and randomly migrated the SCS in control (mean distance=81.69±0.41 μm, velocity=1.15±0.17 μm/h, n=32). Following injury, flat cells showed targeted migration towards the injury site while migrating longer distances (96.73±5.7 μm, n=36, p=.02) and at higher speed (1.7±0.19 μm/h, n=36, p=.02) than in control and emitting filopodia-like structures, reaching towards the injury site. In addition to pre-existing flat cells, we further observed the formation of more flat cells through the transitioning of several resident ECs to a flattened phenotype followed by migration. Histological stainings on perfusion-fixed thick kidney samples revealed that flat cells in the SCS expressed the mesenchymal markers αSMA and vimentin, suggestive of EndMT.Our data identified a novel and dynamic cell population in the SCS, which derives from renal peritubular ECs undergoing EndMT and which participates in renal cell remodeling after acute renal injury.

M3 - Konferenceabstrakt til konference

T2 - DGfN Kongress für Nephrologie 2021

Y2 - 23 September 2021 through 26 September 2021

ER -