Monitoring spatiotemporal changes in chaperone-mediated autophagy in vivo

Abstract

Autophagy malfunctioning occurs in multiple human disorders, making attractive the idea of chemically modulating it with therapeutic purposes. However, for many types of autophagy, a clear understanding of tissue-specific differences in their activity and regulation is missing because of lack of methods to monitor these processes in vivo. Chaperone-mediated autophagy (CMA) is a selective type of autophagy that until now has only been studied in vitro and not in the tissue context at single cell resolution. Here, we develop a transgenic reporter mouse that allows dynamic measurement of CMA activity in vivo using image-based procedures. We identify previously unknown spatial and temporal differences in CMA activity in multiple organs and in response to stress. We illustrate the versatility of this model for monitoring CMA in live animals, organotypic cultures and cell cultures from these mice, and provide practical examples of multiorgan response to drugs that modulate CMA.

Unraveling Cell Death Pathways during Malaria Infection: What Do We Know So Far?

“…There other types of autophagy described: (1) microautophagy, which comprises the lysosomal invagination of cytoplasmic entities for further degradation [ 129 ]; and (2) chaperone-mediated autophagy (CMA), in which the cytosolic chaperone HSPA8/HSC70 recognizes KFERQ-containing proteins and targets them to lysosomal-associated membrane protein 2 (LAMP2) across the lysosomal membrane without the formation of autophagosomes [ 130 , 131 ]. This section focuses on autophagy (hereafter, macroautophagy), a complex process regulated by a set of autophagy-related genes (ATG) and divided into several phases, including initiation, nucleation, elongation, fusion, and degradation [ 125 , 131 ].…”

Hallmarks and detection techniques of cellular senescence and cellular ageing in immune cells

“…To monitor CMA level in vivo, animals with transgenic reporters were developed. The fluorescent protein reporter, tagged with KFERQ sequence, is degraded specifically by CMA (Dong et al, 2020). Cells with high CMA level display lower fluorescent signal, which can be quantified by both microscopy or flow.…”

Impact of Chaperone-Mediated Autophagy in Brain Aging: Neurodegenerative Diseases and Glioblastoma

“…For this, many advances have been done regarding both in vitro and in vivo models for the study of CMA (Juste and Cuervo, 2019 ). Among them, in vitro methods based on the use of a photoconvertible fluorescent reporter (Koga et al, 2011b ) or a “GAPDH-HaloTag” fusion protein (Seki et al, 2012 ; Sato et al, 2016 ), and a recently described transgenic reporter mouse that allows dynamic measurement of CMA activity in vivo (Dong et al, 2020 ) will facilitate further advances in the field.…”