People like to say that what doesn’t kill you makes you stronger, but this phrase takes on a whole new light in view of a new discovery: That the venom from certain tarantulas might be turn out to be a new breed of painkiller.
Millions of people across the world live with chronic pain—affecting more people than cancer, diabetes, heart attack, and stroke combined. Moreover, chronic pain is both a physical and emotional condition, leading to isolation, immobility, and several mental disorders, especially including depression.
Of course, the current solution is generally the prescription of pain medications, which often provide little relief, cause intense drowsiness, and are highly addictive—meaning many are searching intensely for something better to help people manage their pain.
A new type of painkiller
Now, as announced at the Biophysical Society’s 60th Annual Meeting, a group of researchers from the University of Queensland in Brisbane, Australia may have just the solution: venom from the Peruvian green velvet tarantula, Thrixopelma pruriens.
Well, maybe not all of the venom, but rather ProTx-II, a peptide toxin, which is found within it. ProTx-II is extremely potent as a painkiller, while being highly selective in regards to which receptor it works on— Nav 1.7, an important pain receptor.
“It binds to the pain receptor located within the membrane of neuronal cells,” said Sónia Troeira Henriques, senior research officer at the University of Queensland’s Institute for Molecular Bioscience, in a statement, “but the precise peptide-receptor binding site and the importance of the cell membrane in the inhibitory activity of ProTx-II is unknown.”
So to help clarify how the structure of ProTx-II affects its function, the team started by “exploring the structure, the membrane-binding properties, and the inhibitory activity of ProTx-II and a series of analogues,” said Henriques.
To this end, the team used nuclear magnetic resonance (NMR) spectroscopy to explore the 3D shape of ProTx-II, in order to determine whether its structure was a key player in how it inhibits the pain receptor. Further, they used a variety of techniques to characterize the interactions between the molecule and the membrane of neurons to figure out how different properties of ProTx-II affected its interaction with the pain receptor.
“Our results show that the cell membrane plays an important role in the ability of ProTx-II to inhibit the pain receptor,” said Henriques. “In particular, the neuronal cell membranes attract the peptide to the neurons, increase its concentration close to the pain receptors, and lock the peptide in the right orientation to maximize its interaction with the target.”
The group noted that most studies before now have ignored how the cell membrane of neurons might affect the efficacy of venom toxins. Theirs in particular is the first to examine how the membrane-binding properties of ProTx-II is important for its efficacy in blockin the Nav 1.7 pain receptor—opening new doors for the future of pain management.
“Our work creates an opportunity to explore the importance of the cell membrane in the activity of peptide toxins that target other voltage-gated ion channels involved in important disorders,” said Henriques.
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