Researchers\u00a0at VIB, VUB,\u00a0and KU Leuven have\u00a0identified\u00a0a tiny binding site, a molecular\u00a0‘keyhole’,\u00a0in the TRPM3 ion channel, a crucial sensor in pain signaling. TRPM3 is also linked to rare neurodevelopmental disorders and epilepsy. In a recent study published in\u00a0Nature Communications, the\u00a0researchers\u00a0found that even the slightest change in this keyhole can radically switch the channel’s behavior, explaining how certain mutations can flip the effects of drugs.\u00a0<\/p>\n
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If you have the mirror image of your key or you make a very small change to the key or to the keyhole, suddenly the door might open or close.”<\/p>\n
\n <\/p>\nProf.\u00a0Thomas Voets, co-lead of the study, and group leader at VIB and KU Leuven<\/p>\n
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The study also resulted from a strong collaboration between the center in Leuven and Janine Brunner from VUB, which also\u00a0had Alexander\u00a0Shkumatov\u00a0and Stephan Schenck as co-first authors.\u00a0<\/p>\n
Overactivation of TRPM3 is associated with neurodevelopmental\u00a0issues\u00a0and\u00a0epilepsy. Therefore, therapeutic strategies have been looking into inhibiting this channel, and one of the most\u00a0common\u00a0strategies uses\u00a0isosakuranetin, a plant-derived flavonoid. They\u00a0observed\u00a0it\u00a0has two mirror-image forms: S and R. Surprisingly, only the R form fits the pocket and blocks the channel.\u00a0<\/p>\n
“We discovered that the active form of\u00a0isosakuranetin\u00a0is R, not S,”\u00a0Bahar\u00a0Bazeli,\u00a0co-first author of the study. “R is a potent inhibitor of the channel, while S is ineffective.”\u00a0<\/p>\n
The researchers found more.\u00a0A striking finding is\u00a0that patient-derived mutations in this pocket can\u00a0alter\u00a0drug responses.\u00a0<\/p>\n
“Any small change in this pocket can affect the direction of the effect and also the efficacy<\/a>,” explains\u00a0Bazeli. “You can turn an antagonist into an agonist and vice versa. We know now that patients with those specific mutations\u00a0shouldn’t\u00a0use the drug everyone else uses. It\u00a0won’t\u00a0work for them and would only cause side effects without benefit.”\u00a0<\/p>\n
In other words, R would either become ineffective or trigger the channel instead of inhibiting it.\u00a0This plasticity has direct clinical implications, as\u00a0some epilepsy-linked TRPM3 variants lie right in this pocket, which explains why certain medications fail in those patients.\u00a0<\/p>\n
Another\u00a0recent study, published in\u00a0Cell Reports Medicine,\u00a0focused on\u00a0how\u00a0TRPM3\u00a0contributes\u00a0to one of the most severe pain disorders,\u00a0trigeminal neuralgia.\u00a0<\/p>\n
Trigeminal neuralgia\u00a0is caused by injury or compression of the trigeminal nerve in the\u00a0face.\u00a0The scientists found that nerve injury and inflammation<\/a> crank up TRPM3 activity, making facial pain neurons hyperexcitable.\u00a0<\/p>\n
“Trigeminal neuralgia is one of the worst pain syndromes. People call it\u00a0the suicide\u00a0disease because\u00a0it’s\u00a0so\u00a0painful,”\u00a0notes Prof.\u00a0Thomas Voets. “We show that inhibiting TRPM3 works surprisingly well in animal models”.\u00a0<\/p>\n
These findings were\u00a0supported\u00a0by genetic data: certain TRPM3 gene variants (which\u00a0likely make\u00a0the channel more active) are significantly more common in trigeminal neuralgia patients than in the general population. This suggests a genetic predisposition through TRPM3, and linked to the study above, shows why several patients are resistant to general therapies: the different variants cause a different keyhole for the drug, preventing the desired pain-relieving effect.\u00a0<\/p>\n
Together, these studies highlight\u00a0how finding a master key to\u00a0TRPM3\u00a0could be crucial for controlling pain and\u00a0improving\u00a0neurological health. By understanding exactly how molecules fit this lock, drug developers can design better\u00a0‘keys,\u00a0which are\u00a0more potent and selective,\u00a0to treat TRPM3-related conditions.\u00a0Researchers are now designing mutant-specific TRPM3 blockers to translate these findings into personalized pain therapies\u00a0<\/p>\n
“Knowing exactly how a molecule fits in this lock helps a lot with developing better and more specific drugs.\u00a0We are now working on keys that fit even better,”\u00a0concludes\u00a0Voets.\u00a0“These\u00a0studies\u00a0open the door to personalized pain medicine, allowing\u00a0doctors to tailor\u00a0treatments based on a patient’s TRPM3\u00a0‘keyhole’.”\u00a0<\/p>\n
Ultimately, unlocking this molecular keyhole could lead to effective new therapies for chronic pain<\/a> syndromes, neurodevelopmental disorders,\u00a0and epilepsy.\u00a0<\/p>\n
Source:<\/p>\n
Vlaams Instituut voor Biotechnologie<\/a><\/p>\n
Journal reference:<\/p>\n