A Two-Photon Probe Based on Naphthalimide-Styrene Fluorophore for the <i>In Vivo</i> Tracking of Cellular Senescence

Abstract

Cellular senescence is a state of stable cell cycle arrest that can negatively affect the regenerative capacities of tissues and can contribute to inflammation and the progression of various aging-related diseases. Advances in the <i>in vivo</i> detection of cellular senescence are still crucial to monitor the action of senolytic drugs and to assess the early onset or accumulation of senescent cells. Here, we describe a naphthalimide-styrene-based probe (<b>HeckGal</b>) for the detection of cellular senescence both <i>in vitro</i> and <i>in vivo</i>. <b>HeckGal</b> is hydrolyzed by the increased lysosomal β-galactosidase activity of senescent cells, resulting in fluorescence emission. The probe was validated <i>in vitro</i> using normal human fibroblasts and various cancer cell lines undergoing senescence induced by different stress stimuli. Remarkably, <b>HeckGal</b> was also validated <i>in vivo</i> in an orthotopic breast cancer mouse model treated with senescence-inducing chemotherapy and in a renal fibrosis mouse model. In all cases, <b>HeckGal</b> allowed the unambiguous detection of senescence <i>in vitro</i> as well as in tissues and tumors <i>in vivo</i>. This work is expected to provide a potential technology for senescence detection in aged or damaged tissues.