Biology subjects

Rolas, L.

Publications and source records attributed to Rolas, L..

5 recordsLinked to original sources

bioRxiv2026

Orphan GPR84 facilitates uropod de-adhesion to terminate leukocyte diapedesis during inflammation

Leukocyte migration through venular walls is an essential component of effective immunity. While the key molecular players driving the initial steps of this response are known, the terminating signals remain unclear. Here, we have identified a conserved role for GPR84 family GPCRs in successful completion of the final stages of leukocyte extravasation through acutely inflamed vessels. The integration of high resolution intravital imaging with cell-specific genetics revealed that genetic deficiency of GPR84 orthologues in mice and Drosophila, results in defective detachment of transmigrating immune cells from vessel walls. Mechanistically, transcriptomics revealed GPR84-deficient neutrophils exhibit defective actin cytoskeletal regulation and cellular adhesion/de-adhesion. Consistent with this, our fly-murine pipeline shows that GPR84 supports localized and dynamic Rho activation to enable detachment of the immune cell uropod from vessel exit sites. Moreover, pharmacological blockade of GPR84 signaling dampened immune cell migration in multiple murine acute inflammatory settings. Collectively, our findings present GPR84 as a novel physiological regulator of immune cell extravasation that is amenable to therapeutic targeting for modulating leukocyte infiltration into inflamed tissues. SummaryHere we identify the GPR84 family of GPCRs as key regulators of effective immune cell extravasation in vivo. Mechanistically, through integrating genetically tractable Drosophila and murine in vivo models, we show how leukocyte GPR84 supports dynamic Rho-dependent detachment of stretched uropods as these cells exit vessels.

immunology↗

bioRxiv2025

Force sensing by Piezo1 regulates endothelial secretory granule exocytosis

Endothelial cells (ECs) rapidly alter their phenotype to support haemostasis and inflammation through the exocytosis of specialised storage organelles, known as Weibel-Palade bodies (WPBs). This exocytic response is stimulated by a variety of physiological and pathological triggers which act through well-described transmembrane receptors. However, the influence of mechanical forces and how they shape this fundamental endothelial response remains relatively unexplored. Here we demonstrate that opening of the mechanosensitive cation channel Piezo1 on the EC surface triggers rapid WPB exocytosis. The dynamics and mechanisms were investigated using the Piezo1 agonist (Yoda1) and by modelling mechanical opening through EC-ICAM-1 ligation by THP-1 cells under low shear flow. In vitro, localised von Willebrand Factor (VWF) secretion occurred at THP-1 adhesion sites, suggesting a reciprocity of VWF release alongside leukocyte capture. In vivo, Yoda1 stimulation of tissues resulted in a dramatic increase in neutrophil and platelet adhesion to postcapillary venular walls, spatially aligned with cargo release (VWF). The rapid dynamics of this response was revealed by the application of high resolution confocal intravital microscopy to transgenic EGFP-Rab27a mice that exhibit fluorescent WPBs and neutrophils. These data reveal a previously unrecognised instigator of WPB exocytosis and uncover a mechanosensitive molecular pathway coupling inflammation with haemostasis. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=166 SRC="FIGDIR/small/678766v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@d8ed6org.highwire.dtl.DTLVardef@1cbc0corg.highwire.dtl.DTLVardef@7dd6a9org.highwire.dtl.DTLVardef@197f286_HPS_FORMAT_FIGEXP M_FIG Graphical abstract: Activation of Piezo1 by pharmacological agonism or leukocyte adherence to ICAM-1 under low flow promotes VWF secretion and platelet capture through a protein kinase C-dependent mechanism. C_FIG SUMMARYThis research describes how the mechanosensitive cation channel Piezo1 elicits the rapid exocytosis of endothelial secretory organelles, provoking platelet capture to sites of leukocyte adherence. The EGFP-Rab27a transgenic mouse demonstrates a technical advance, facilitating intravital imaging of endothelial secretory organelles.

cell biology↗

bioRxiv2024

Leukocytes use endothelial membrane tunnels to extravasate the vasculature

Upon inflammation, leukocytes extravasate through endothelial cells. When they extravasate in a paracellular manner, it is generally accepted that neighbouring endothelial cells physically disconnect to open cell-cell junctions, allowing leukocytes to cross. When carefully examining endothelial junctions, we found a partial membrane overlap of endothelial cells beyond VE-cadherin distribution. These overlaps are regulated by actin polymerization and, although marked by, do not require PECAM-1, nor VE-cadherin. Neutrophils prefer wider membrane overlaps as exit sites. Detailed 3D analysis of endothelial membrane dynamics during paracellular neutrophil transmigration in real-time, at high spatiotemporal resolution using resonant confocal and lattice light-sheet imaging, revealed that overlapping endothelial membranes form a tunnel during neutrophil transmigration. These tunnels are formed by the neutrophil lifting the membrane of the upper endothelial cell while indenting and crawling over the membrane of the underlying endothelial cell. Our work shows that endothelial cells do not simply retract upon passage of neutrophils but provide membrane tunnels, allowing neutrophils to extravasate. This discovery defines the 3D multicellular architecture in which the paracellular transmigration of neutrophils occurs.

cell biology↗

bioRxiv2023

Comprehensive analysis of A-type lamin tail region for repairing the nuclear lamina

The nuclear lamina (NL) lines the nuclear envelope (NE) to maintain nuclear structure in metazoan cells. The major NL components, the nuclear lamins contribute to the protection against NE rupture induced by mechanical stress. Lamin A (LA) and a short form of the splicing variant lamin C (LC) are diffused from the nucleoplasm to sites of NE rupture in immortalized mouse embryonic fibroblasts (MEFs). LA localization to the rupture sites is significantly slow and weak compared to LC because of its relatively small pool in the nucleoplasm, but the precise mechanism remains unknown. In this study, we induce NE rupture in wild-type and LA/C-knockout MEFs, and Hutchinson-Gilford Progeria syndrome (HGPS) knock-in MEFs that express progerin, a LA mutant lacking the second proteolytic cleavage site, by laser microirradiation and AFM indentation. The farnesylation at the CaaX motif of unprocessed LA and the inhibition of the second proteolytic cleavage decrease the nucleoplasmic pool and slow the localization to the rupture sites in a long-time window (60-70 min) after the induction of NE rupture. Our data could explain the defective repair of NE rupture in HGPS through the farnesylation at the CaaX motif of unprocessed progerin. In addition, unique segments in LA-specific tail region cooperate with each other to inhibit the rapid accumulation within a short-time window (3 min) that is also observed with LC. Significance StatementNuclear lamins are the major components of the nuclear lamina (NL) that lies the nuclear envelope (NE). Lamin A (LA) is slowly localized to sites of nuclear envelope (NE) rupture compared to lamin C (LC). This study reveals that the farnesylation at the CaaX motif of unprocessed LA and the inhibition of the second proteolytic cleavage decrease the nucleoplasmic pool and slow the localization to the rupture sites within a long-time window (60-70 min) after the induction of NE rupture, which could explain the defective repair of NE rupture in Hutchinson-Gilford Progeria syndrome (HGPS). Additionally, unique segments in LA-specific tail region are critical for inhibiting the rapid accumulation within a short-time window (3 min).

cell biology↗

bioRxiv2020

Isoprenylcysteine carboxylmethyltransferase basedtherapy for Hutchinson Gilford progeria syndrome

Progerin is a mutant prelamin A variant that causes Hutchinson-Gilford progeria syndrome (HGPS, progeria), a rare genetic disease characterized by premature aging and death in childhood. Although several therapeutic approaches have been explored in experimental models, clinical trials have shown very limited benefits in HGPS patients. Here, we describe the development of UCM-13207, a new potent inhibitor of isoprenylcysteine carboxylmethyltransferase (ICMT) that reduces progerin nuclear accumulation and ameliorates the typical alterations in progeroid human and mouse cells. UCM-13207 also improves phenotypic anomalies and extends lifespan in progerin-expressing LmnaG609G/G609G mice. These results support the potential use of UCM-13207 as a new treatment for progeria.

pharmacology and toxicology↗