Interrogating CD38 & PARG with the Transcreener ADPR Assay

The Transcreener ADPR Assay is a biochemical HTS assay for quantitative measurement of ADP-ribose (ADPR) production in enzymatic reactions. The assay uses a coupling enzyme to convert ADPR into AMP, which is then detected using a far-red, competitive fluorescence polarization (FP) assay. As examples, the Transcreener ADPR Assay can be used to detect the activity of human Cluster of Differentiation 38 (CD38) or Poly (ADP-ribose) glycohydrolase (PARG). CD38 modulates cellular NAD homeostasis by degrading NAD to produce ADPR. It has implications for several pathophysiological conditions, including infection, aging, and tumorigenesis. PARG produces ADPR from the breakdown of poly-ADP-ribose. It plays an important role in DNA damage repair and has been seen as a potential target for anticancer therapy. 

Here, we demonstrate how the Transcreener ADPR Assay will provide a reliable and robust tool for the discovery of CD38 and PARG inhibitors. We show the sensitivity and selectivity of the assay, followed by the ability to obtain robust assay signals (>100mP) with less than 10 pM of enzyme and a Z' value greater than 0.7. The assay was validated in a pilot screen of 1280 pharmacologically active molecules, which identified one inhibitor for CD38. The Transcreener ADPR FP Assay is a powerful tool for discovery of CD38 and PARG antagonists that will accelerate efforts to modulate these targets pharmacologically.