Oral Presentation 8th Venoms to Drugs 2023

Mending achy breaky hearts: Cyclic peptides inhibitors of ASIC1a as therapeutics for ischemic heart disease  (#26)

Daniela Rojas-Azofeifa 1 , Toby Passioura 2 , Hiroaki Suga 3 , Nathan Palpant 1 , Glenn King 1
  1. The University of Queensland, St. Lucia , Qld, Austrlia
  2. The University of Sydney, Sydney , New South Wales, Australia
  3. The University of Tokyo, Bunkyō, Tokyo, Japan

The proton-gated acid-sensing ion channel 1a (ASIC1a) is implicated in myocardial ischemia-reperfusion injury (IRI). Pharmacological inhibition of ASIC1a produces robust cardioprotection in models of cardiac ischemia. Thus, inhibition of this channel is an important target for cardioprotection with potential application in the treatment of IRI. The most potent known inhibitor of ASIC1a is Hi1a (IC50= 500 pM), a 76-residues spider venom peptide, with two inhibitor cystine knot domains isolated from K’gari funnel-web, Hydronyche infensa. However, due to the large size and complexity of Hi1a, the large-scale production of this peptide is highly challenging. Therefore, smaller and less complex peptides with high potency are required as ASIC1a therapeutic candidates for the treatment of IRI.

In my research, I assessed seven small cyclic peptide inhibitors (CPIs) of 1.5-2 KDa developed using Random nonstandard Peptide Integrated Discovery (RaPID). These CPIs inhibit human ASIC1a with 0.3-5.4 nM affinity, and I determined if they protect cardiomyocytes against acidosis-hypoxic injury. I measured cell death after exposure of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to different pHs in hypoxic conditions with or without CPIs, and mimicking IRI conditions. Furthermore, using automated whole-cell patch-clamp electrophysiology, the lead CPI candidate was screened against key off-target voltage-gated sodium and potassium channels important in the nervous system, heart and muscle. I also examined the stability of this peptide in human serum and its interaction with human serum albumin. In conclusion, cyclic peptide D04, in particular, provides robust cardioprotection in an in vitro IRI model, and it appeared to be the best cardioprotective targeting ASIC1a drug candidate for further characterisation.  

  1. Redd, M. A., et al. (2021). Therapeutic Inhibition of Acid-Sensing Ion Channel 1a Recovers Heart Function after Ischemia-Reperfusion Injury. Circulation, 947–960. https://doi.org/10.1161/CIRCULATIONAHA.121.054360
  2. Passioura, T., & Suga, H. (2017). A RaPID way to discover nonstandard macrocyclic peptide modulators of drug targets. Chemical Communications, 53(12), 1931–1940. https://doi.org/10.1039/c6cc06951g
  3. Chassagnon, I. R., et al. (2017). Potent neuroprotection after stroke afforded by a double-knot spider-venom peptide that inhibits acid-sensing ion channel 1a. Proceedings of the National Academy of Sciences of the United States of America, 114(14), 3750–3755.