Search

Endoscopic ultrasound-guided fine needle aspiration biopsy (EUS FNAB) is a well established diagnostic method in adult patients, but is rarely used in the paediatric population. The Clinical Department of Gastroenterology at the University Clinical Centre Ljubljana and the Department of Cytopathology at the Institute of Pathology, Faculty of Medicine, University of Ljubljana, Slovenia, have been closely collaborating on EUS FNAB since the introduction in 2010. The aim of the study was to review the cases of EUS FNAB of pancreatic neoplasms in children.

Inactivation of the endosomal sorting complex required for transport (ESCRT) machinery has been reported to cause autophagic defects, but the exact functions of ESCRT proteins in macroautophagy/autophagy remain incompletely understood. Using live-cell fluorescence microscopy we found that the filament-forming ESCRT-III subunit CHMP4B was recruited transiently to nascent autophagosomes during starvation-induced autophagy and mitophagy, with residence times of about 1 and 2 min, respectively. Correlative light microscopy and electron tomography revealed CHMP4B recruitment at a late step in mitophagosome formation. The autophagosomal dwell time of CHMP4B was strongly increased by depletion of the regulatory ESCRT-III subunit CHMP2A. Using a novel optogenetic closure assay we observed that depletion of CHMP2A inhibited phagophore sealing during mitophagy. Consistent with this, depletion of CHMP2A and other ESCRT-III subunits inhibited both PRKN/PARKIN-dependent and -independent mitophagy. We conclude that the ESCRT machinery mediates phagophore closure, and that this is essential for mitophagic flux. Abbreviations: BSA: bovine serum albumin; CHMP: chromatin-modifying protein; CLEM: correlative light and electron microscopy; EGFP: enhanced green fluorescent protein; ESCRT: endosomal sorting complex required for transport; HEPES: 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid; HRP: horseradish peroxidase; ILV: intralumenal vesicle; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; LOV2: light oxygen voltage 2; MLS: mitochondrial localization sequence; MT-CO2: mitochondrially encoded cytochrome c oxidase II; O+A: oligomycin and antimycin A; PBS: phosphate-buffered saline; PIPES: piperazine-N,N-bis(2-ethanesulfonic acid); PRKN/PARKIN: parkin RBR E3 ubiquitin protein ligase; RAB: RAS-related in brain; SD: standard deviation; SEM: standard error of the mean; TOMM20: TOMM20: translocase of outer mitochondrial membrane 20; VCL: vinculin; VPS4: vacuolar protein sorting protein 4; Zdk1: Zdark 1; TUBG: Tubulin gamma chain [ABSTRACT FROM AUTHOR]

Thrombin is elevated at sites of neurotrauma and well known for its ability to generate fibrin monomers supporting hemostasis. In addition, thrombin is a high affinity agonist for Protease Activated Receptor 1 (PAR1), also known as the thrombin receptor. PAR1 is a seven transmembrane G-protein-coupled receptor that is activated by proteolysis within its extracellular N-terminus. Signaling at PAR1 is emerging as an important translator of the extracellular proteolytic microenvironment into cellular responses that contribute to tissue injury, remodeling and regeneration. In this study, we critically evaluated the role and mechanism of action of PAR1 in spinal cord injury (SCI) by determining the impact of PAR1 gene deletion on functional recovery and cellular and molecular signs of pathogenesis in experimental murine contusion-compression SCI. SCI in PAR1 knockout mice was associated with greater improvements in motor coordination and strength compared to wild type littermates. Molecular profiling of the injury site demonstrated PAR1-/- mice had significantly attenuated elevations in pro-inflammatory cytokines (IL-6, TNF and IL-1β) and in key hallmarks of astrogliosis (GFAP, vimentin, neurocan). SCI in PAR1-/- mice was also accompanied by improved preservation of PKC-Ypositive corticospinal axons, and reductions in BIM expression and STAT3 signaling. The mechanistic link between PAR1, STAT3 and astrogliosis was investigated in primary astrocyte cultures revealing that thrombin promotes IL-6 secretion in a PAR1-dependent manner. A model is proposed where PAR1-elicited IL-6 secretion drives expression of GFAP and vimentin through canonical STAT3 signaling. Since IL-6 also markedly increased the expression of PAR1 and thrombin by astrocytes, these data collectively point to an IL-6-driven PAR1 signaling circuit that works hand-in-hand with STAT3 to promote inflammatory-astrogliosis. Given the superior neuromotor recovery observed in PAR1 knockout mice, we suggest that targeting PAR1 to limit inflammation and astrogliosis represents a promising drug target to reduce axon degeneration and improve motor outcomes after SCI. [ABSTRACT FROM AUTHOR]