title: Sensitive detection of lysosomal membrane permeabilization by lysosomal galectin puncta assay.
abstract: Lysosomal membrane permeabilization (LMP) contributes to tissue involution, degenerative diseases, and cancer therapy. Its investigation has, however, been hindered by the lack of sensitive methods. Here, we characterize and validate the detection of galectin puncta at leaky lysosomes as a highly sensitive and easily manageable assay for LMP. LGALS1/galectin-1 and LGALS3/galectin-3 are best suited for this purpose due to their widespread expression, rapid translocation to leaky lysosomes and availability of high-affinity antibodies. Galectin staining marks individual leaky lysosomes early during lysosomal cell death and is useful when defining whether LMP is a primary or secondary cause of cell death. This sensitive method also reveals that cells can survive limited LMP and confirms a rapid formation of autophagic structures at the site of galectin puncta. Importantly, galectin staining detects individual leaky lysosomes also in paraffin-embedded tissues allowing us to demonstrate LMP in tumor xenografts in mice treated with cationic amphiphilic drugs and to identify a subpopulation of lysosomes that initiates LMP in involuting mouse mammary gland. The use of ectopic fluorescent galectins renders the galectin puncta assay suitable for automated screening and visualization of LMP in live cells and animals. Thus, the lysosomal galectin puncta assay opens up new possibilities to study LMP in cell death and its role in other cellular processes such as autophagy, senescence, aging, and inflammation.
authors.affiliation: a Cell Death and Metabolism Unit; Center for Autophagy, Recycling and Disease; Danish Cancer Society Research Center ; Copenhagen , Denmark.
authors.forename: Sonja
authors.initials: S
authors.lastname: Aits
authors.forename: Jennifer
authors.initials: J
authors.lastname: Kricker
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Ellegaard
authors.forename: Saara
authors.initials: S
authors.lastname: Hämälistö
authors.forename: Siri
authors.initials: S
authors.lastname: Tvingsholm
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Corcelle-Termeau
authors.forename: Søren
authors.initials: S
authors.lastname: Høgh
authors.forename: Thomas
authors.initials: T
authors.lastname: Farkas
authors.forename: Anna
authors.initials: A
authors.lastname: Holm Jonassen
authors.forename: Irina
authors.initials: I
authors.lastname: Gromova
authors.forename: Monika
authors.initials: M
authors.lastname: Mortensen
authors.forename: Marja
authors.initials: M
authors.lastname: Jäättelä
mesh_terms: D000818:Animals; D017209:Apoptosis; D001343:Autophagy; D001798:Blood Proteins; D001940:Breast / Q000473:pathology; D017173:Caenorhabditis elegans / Q000502:physiology; D016923:Cell Death; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability; D002470:Cell Survival; D005260:Female; D037483:Galectin 1 / Q000378:metabolism; D037502:Galectin 3 / Q000378:metabolism; D037161:Galectins / Q000737:chemistry*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007249:Inflammation; D007425:Intracellular Membranes / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism*; D061986:MCF-7 Cells; D051379:Mice; D018613:Microscopy, Confocal; D009368:Neoplasm Transplantation; D021381:Protein Transport
chemical_list: D001798:Blood Proteins; D037483:Galectin 1; D037502:Galectin 3; D037161:Galectins; C445499:LGALS1 protein, human; C428445:LGALS3 protein, human; D049452:Green Fluorescent Proteins
keywords: C. elegans; breast involution; cell death; galectin; lysosome