Chemiluminescent Probes for Activity-Based Sensing of Formaldehyde Released from Folate Degradation in Living Mice

Abstract

<p class="first" id="P1">Formaldehyde (FA) is a common environmental toxin that is also produced naturally in the body through a wide range of metabolic and epigenetic processes, motivating the development of new technologies to monitor this reactive carbonyl species (RCS) in living systems. Here, we report a pair of first-generation chemiluminescent probes for selective formaldehyde detection. Caging phenoxy-dioxetane scaffolds bearing different electron-withdrawing groups with a general 2-aza-Cope reactive formaldehyde trigger provides Chemiluminescent Formaldehyde Probes 540 and 700 ( <b>CFAP540</b> and <b>CFAP700</b>) for visible and near-IR detection of FA in living cells and mice, respectively. In particular, <b>CFAP700</b> is capable of visualizing FA release derived from endogenous folate metabolism, providing a starting point for the use of CFAPs and related chemical tools to probe FA physiology and pathology, as well as for the development of a broader palette of chemiluminescent activity-based sensing (ABS) probes that can be employed from in vitro biochemical to cell to animal models. </p><p id="P2">COMMUNICATION</p><p id="P3">A first-generation set of chemiluminescent activity-based sensing probes for <i>in vivo</i> imaging of formaldehyde is reported. A formaldehyde-selective trigger is used to cage a phenol-dioxetane scaffold that emits a photon after aza-Cope-dependent uncaging. These reagents were utilized to image formaldehyde fluxes in living cells and mice, enabling the unique identification of endogenous formaldehyde production from metabolic folate cycles <i>in vivo</i>. </p><p id="P4"> <div class="figure-container so-text-align-c"> <img alt="" class="figure" src="/document_file/d13b0676-6de9-4137-805e-e38fb61a4470/PubMedCentral/image/nihms-1003215-f0006.jpg"/> </div> </p>