Synthesis and evaluation of esterified Hsp70 agonists in cellular models of protein aggregation and folding

Abstract

Over-expression of the Hsp70 molecular chaperone prevents protein aggregation and ameliorates neurodegenerative disease phenotypes in model systems. We identified an Hsp70 activator, MAL1–271, that reduces α-synuclein aggregation in a Parkinson’s Disease model. We now report that MAL1–271 directly increases the ATPase activity of a eukaryotic Hsp70. Next, twelve MAL1–271 derivatives were synthesized and examined in a refined α-synuclein aggregation model as well as in an assay that monitors maturation of a disease-causing Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) mutant, which is also linked to Hsp70 function. Compared to the control, MAL1–271 significantly increased the number of cells lacking α-synuclein inclusions and increased the steady-state levels of the CFTR mutant. We also found that a nitrile-containing MAL1–271 analog exhibited similar effects in both assays. None of the derivatives exhibited cellular toxicity at concentrations up to 100µM, nor were cellular stress response pathways induced. These data serve as a gateway for the continued development of a new class of Hsp70 agonists with efficacy in these and potentially other disease models.

Synthesis and Selective Functionalization of Thiadiazine 1,1-Dioxides with Efficacy in a Model of Huntington’s Disease

“…After developing a versatile strategy and reaction conditions for the preparation and sequential functionalization of thiadiazine 1,1-dioxides, we investigated our hypothesis that this heterocyclic core could be a suitable replacement for a dihydropyrimidine-2-one and show similar efficacy in a model of neurodegenerative disease. 38,39 Therefore, ten structurally related analogs of the Biginelli product MAL1-271 were selected for a cell-based screen in a Huntington's disease (HD) model (Figure 2). HD is an ultimately fatal neurodegenerative disorder that is caused by a polyglutamine repeat expansion in the Huntingtin protein (HTT).…”

Proteostasis Regulators in Cystic Fibrosis: Current Development and Future Perspectives

“…Finally, none of the derivatives exhibited cellular toxicity nor induced cellular stress response pathways, in contrast to what was observed with Hsp70 inhibitors, which are mostly cytotoxic. Taken together, these results serve as a gateway for the development of new Hsp70 agonists and for further optimization of the pharmacokinetic properties of this pyrimidinone–peptoid class of compounds …”

Hsp70 and the Unfolded Protein Response as a Challenging Drug Target and an Inspiration for Probe Molecule Development

“…In particular, MAL1-271 has proven to be an effective activator of ATP turnover in Hsp70/J-protein assays. 34 In combination with the Hsp-70 antagonist, MAL3-101, MAL1-271 has been an important tool compound to test hypotheses on the effects of Hsp70 activity on synuclein aggregation 35 and heat shock defenses in the cortex. 36 MAL1-271 binds to the same allosteric, J-protein (Hsp40) pocket as MAL2-11B 25 and, by inference, MAL3-101, making it a mechanistically relevant and particularly valuable positive control compound, as well as a potential lead structure for the development of antineurodegenerative, Hsp70 based therapeutics.…”

“…While our group’s initial interest was mainly in the development of Hsp70 inhibitors, in order to control cancer growth, viral infections, and parasitic infections such as malaria, screening of the readily synthesized library of dihydropyrimidinones 2 and 3 also identified agonists of the chaperone, which could be of significant therapeutic relevance in neurodegenerative diseases. In particular, MAL1-271 has proven to be an effective activator of ATP turnover in Hsp70/J-protein assays . In combination with the Hsp-70 antagonist, MAL3-101, MAL1-271 has been an important tool compound to test hypotheses on the effects of Hsp70 activity on synuclein aggregation and heat shock defenses in the cortex .…”