Chromo-fluorogenic probes for β-galactosidase detection

Abstract

β-Galactosidase (β-Gal) is a widely used enzyme as a reporter gene in the field of molecular biology which hydrolyses the β-galactosides into monosaccharides. β-Gal is an essential enzyme in humans and its deficiency or its overexpression results in several rare diseases. Cellular senescence is probably one of the most relevant physiological disorders that involve β-Gal enzyme. In this review, we assess the progress made to date in the design of molecular-based probes for the detection of β-Gal both in vitro and in vivo. Most of the reported molecular probes for the detection of β-Gal consist of a galactopyranoside residue attached to a signalling unit through glycosidic bonds. The β-Gal-induced hydrolysis of the glycosidic bonds released the signalling unit with remarkable changes in colour and/or emission. Additional examples based on other approaches are also described. The wide applicability of these probes for the rapid and in situ detection of de-regulation β-Gal-related diseases has boosted the research in this fertile field. 33, 34 HBSS buffer 570/680 Turn on C6-lacZ 35 PBS (10 mM, pH 7.4) 405/545 Turn on C6-lacZ 36 HBSS buffer 640/680 Turn on HCT116-lacZ 37-39 HEPES (pH 7.3)-DMSO 99.9:0.01 v/v 555/582 Turn on COS-7-lacZ 40 PBS-EtOH/10:1 375/↓450↑5 40 Ratiometric (Twophoton) HEK293-lacZ 41 PBS 430/550 Turn on HeLa, HepG and HCT-116 + β-Gal (1 U) cell lines with high β-Gal activity per se 42 PBS 344/512 Turn on OVCAR-3 43 H2O-THF 99:1 333/495 Turn on (aggregates) OVCAR-3 44 PBS (20 mM, pH 4.6) 420/565 Turn on (aggregates) SKOV-3 45 PBS 488/560 Turn on (Twophoton) SKOV-3 46 PBS 350/↓450↑5 50 Ratiometric (Twophoton) OVCAR-3 47 PBS/DMSO 7:3 (50 mM, pH = 7.4) 460/650 Turn on (aggregates) OVCAR-3 48 PBS (10 mM, pH 7.4) 410/↓580↑6 50 Ratiometric OVCAR-3 49 PBS/DMSO 99/1 (0.05 M, pH 7.4)

Gene-Directed Enzyme Prodrug Therapy by Dendrimer-Like Mesoporous Silica Nanoparticles against Tumor Cells

“…The DOXO-Gal prodrug has been previously studied in systems where β-gal is naturally overexpressed [ 56 , 57 ]. Moreover, we also demonstrated the use of other galactose-functionalized prodrugs based on Navitoclax for selectively killing senescent cells, which overexpress β-gal [ 58 ], galactose-functionalized dyes for senescent cell detection [ 59 , 60 , 61 , 62 ] or the use of galactose-capped nanoparticles for programmed cargo delivery in senescent cells taking advantage of the overexpression of β-gal [ 63 , 64 ]. In addition, the pair β-gal/DOXO-Gal has previously been successfully reported in the literature [ 65 ].…”

Current Scenario of Pathogen Detection Techniques in Agro-Food Sector

“…This approach of bacterial selection and detection can be at more than one level where more than one unique chromogenic enzyme and selective agent are employed for better identification and specificity [ 34 ]. The bacterial hydrolases (β-glucosidase or β-galactosidase) are the most common enzymes that are targeted because of their chromogenic substrates [ 35 , 36 ]. These chromogenic substrates provide a bright color after reaction by the bacterial enzyme and differentiate the colonies on the basis of the presence of a targeted enzyme.…”

Developing a far-red fluorogenic beta-galactosidase probe for senescent cell imaging and photoablation

“…Beta-galactosidase (β-gal), a glycoside hydrolase that catalyzes the hydrolysis of a terminal β- d -galactose residue, has been commonly applied to monitor gene expression, 1–4 transcriptional regulation, 5,6 and recently, senescence. 7–9 Cellular senescence, a stress-induced irreversible growth arrest, accumulates in aged organisms and contributes to tissue dysfunction thus drives age-related phenotypes. 10 The senescent cells express several characteristic senescence biomarkers, such as senescence-associated β-gal (SA-β-gal), reactive oxygen species, p21, and senescence-associated secretory phenotype (SASP) factors.…”

“…23 A photosensitive senolytic, which can be activated on demand to ablate specific senescent cells in a defined location, avoiding the widespread non-specific killing, may have a far-reaching contribution to study the neighboring effect of senescent cells. Although a number of β-gal activatable fluorescence probes have been reported, 8 the β-gal activatable photodynamic agent is still limited. 24–26 We thus design a novel β-gal activatable photosensitive probe, named Gal-MB, for senescent cell identification and selective photoelimination, based on a recently developed enzyme activatable methylene blue (MB) construct, gGluMB, which is an activatable photosensitizer sensitive to gamma-glutamyl transpeptidase.…”