A Fluorogenic Far Red-Emitting Molecular Viscometer for Ascertaining Lysosomal Stress in Live Cells and Caenorhabditis elegans.

Apurba Lal Koner,Ashutosh Kanojiya,Akshay Silswal

doi:10.3389/fchem.2022.840297

Apurba Lal Koner, Ashutosh Kanojiya + Show 1 more

Open Access

https://doi.org/10.3389/fchem.2022.840297

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Abstract

The cellular physiochemical properties such as polarity, viscosity, and pH play a critical role in cellular homeostasis. The dynamic change of lysosomal viscosity in live cells associated with different environmental stress remains enigmatic and needs to be explored. We have developed a new class of Julolidine-based molecular viscometers with an extended π-conjugation to probe the lysosomal viscosity in live cells. High biocompatibility, pH tolerance, and the fluorogenic response with far red-emission (>600 nm) properties make these molecular viscometers suitable for live-cell fluorescence imaging in Caenorhabditis elegans. Among these probes, JIND-Mor is specifically designed to target lysosomes via simple modification. The real-time monitoring of lysosomal viscosity change under cellular stress was achieved. We believe that such a class of molecule viscometers has the potential to monitor lysosomal health in pathogenic conditions.

Highlights

The microenvironmental cellular properties play an important role in biological function (Chambers et al, 2018)
Compound 1 was synthesized from the SCHEME 1 | Structure of molecular rotors (A) previously developed julolidine-based, (B) DCAJ, and JIND-Mor in this work
Molecular rotor has three components-donor (D) group, a bulky acceptor (A) unit, and a lysosome selective targeting group remotely connected to acceptor

Summary

INTRODUCTION

The microenvironmental cellular properties play an important role in biological function (Chambers et al, 2018). The lysosome, a membrane-bound spherical organelle, is known as the digestive compartment of the cells and plays an important role in cellular homeostasis (Lawrence and Zoncu, 2019). 9-(dicyanovinyl)-julolidine, 9-(2-carboxy-2-cyanovinyl) julolidine, and their suitable derivatives are well explored for quantifying the cellular viscosity (Kung and Reed, 1989; Haidekker et al, 2001; Shao et al, 2011) They suffer from small Stokes shift and high-energy excitation, which limits their applicability for in vivo applications (Haidekker et al, 2001). To overcome these limitations, we have developed a far-red emitting pH-tolerant molecular viscometer DCAJ with a fluorogenic response. Morpholine-appended fluorescent probes are known to localize selectively inside lysosomal compartment due to its protophilic nature associated with the low pKa value in the range of 5–6 (Wang et al, 2013; Li et al, 2018; Kong et al., 2019; Biswas et al, 2021)

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT