Research Projects

This proposal aims to develop stabilizers of a patient-derived immunoglobulin light chain (LC) called Mcg, which can inhibit light chain amyloidosis (AL) by stabilizing the dimer. Mcg binds to a few ligands with weak affinity, such as sulfasalazine and SSZ, which inhibit aggregation only at millimolar concentration. The dimeric interface of Mcg contains nucleophilic amino acids, including Y38, Y34, and S36. The researchers will install Tyr- or Ser-targeted warheads on a suitable Mcg ligand to develop covalent stabilizers that react with these amino acids, leading to irreversible inhibition of aggregation. These covalent stabilizers will be converted to activity-based probes (ABPs) that enable conjugation of fluorophores or biotin to Mcg via click chemistry. The researchers will also set up a virtual screening-molecular dynamics simulation platform to identify novel Mcg-binding scaffolds. This will establish the foundation for developing potent Mcg stabilizers through structure-based drug design. The researchers will characterize Mcg stabilizers using isothermal titration calorimetry (ITC) and thermal shift assay (TSA), as well as a target engagement assay that relies on the inhibition of Mcg labeling by ABPs in the presence of a competing ligand. The researchers will also monitor the inhibition of Mcg aggregation by the stabilizers using Thioflavin-T, size-exclusion chromatography, and electron microscopy. The researchers will also study the uptake of Mcg and its aggregates by cells using fluorescence imaging and investigate the mechanism using known inhibitors of various cellular uptake and cell death pathways. They will also explore the induction of oxidative stress by Mcg, as some AL-associated LCs cause this.