Activity of botulinum toxin type A in cranial dura: implications for treatment of migraine and other headaches.

BJP DOI:10.1111/bph.13366 www.brjpharmacol.org British Journal of Pharmacology RESEARCH PAPER Activity of botulinum toxin type A in cranial dura: implications for treatment of migraine and other headaches Correspondence Zdravko Lacković, Laboratory of Molecular Neuropharmacology, Department of Pharmacology, University of Zagreb School of Medicine, Šalata 11, 10000 Zagreb, Croatia. E-mail: ; --------------------------------------------------------- Received 14 May 2015 Revised Zdravko Lacković1, Boris Filipović1,2, Ivica Matak1 and Zsuzsanna Helyes3,4 1 Laboratory of Molecular Neuropharmacology, Department of Pharmacology, University of Zagreb School of Medicine, Šalata 11, 10000 Zagreb, Croatia, 2Department of Otorhinolaryngology-Head 30 July 2015 Accepted 1 October 2015 and Neck Surgery, University Hospital Sveti Duh, Sveti Duh 64, 10000 Zagreb, Croatia, 3 Department of Pharmacology and Pharmacotherapy, University of Pécs School of Medicine, Szigeti u. 12, H-7624 Pécs, Hungary, and 4János Szentágothai Research Center, 3MTA-PTE NAP B Pain Research Group, University of Pécs School of Medicine, Ifjúság útja 20, H-7624 Pécs, Hungary BACKGROUND AND PURPOSE Although botulinum toxin type A (BoNT/A) is approved for chronic migraine treatment, its mechanism of action is still unknown. Dural neurogenic inflammation (DNI) commonly used to investigate migraine pathophysiology can be evoked by trigeminal pain. Here, we investigated the reactivity of cranial dura to trigeminal pain and the mechanism of BoNT/A action on DNI. EXPERIMENTAL APPROACH Because temporomandibular disorders are highly comorbid with migraine, we employed a rat model of inflammation induced by complete Freund’s adjuvant, followed by treatment with BoNT/A injections or sumatriptan p.o. DNI was assessed by Evans blueplasma protein extravasation, cell histology and RIA for CGRP. BoNT/A enzymatic activity in dura was assessed by immunohistochemistry for cleaved synaptosomal-associated protein 25 (SNAP-25). KEY RESULTS BoNT/A and sumatriptan reduced the mechanical allodynia and DNI, evoked by complete Freund’s adjuvant. BoNT/A prevented inflammatory cell infiltration and inhibited the increase of CGRP levels in dura. After peripheral application, BoNT/A-cleaved SNAP-25 colocalized with CGRP in intracranial dural nerve endings. Injection of the axonal transport blocker colchicine into the trigeminal ganglion prevented the formation of cleaved SNAP-25 in dura. CONCLUSIONS AND IMPLICATIONS Pericranially injected BoNT/A was taken up by local sensory nerve endings, axonally transported to the trigeminal ganglion and transcytosed to dural afferents. Colocalization of cleaved SNAP-25 and the migraine mediator CGRP in dura suggests that BoNT/A may prevent DNI by suppressing transmission by CGRP. This might explain the effects of BoNT/A in temporomandibular joint inflammation and in migraine and some other headaches. Abbreviations BoNT/A, botulinum toxin type A; CFA, complete Freund’s adjuvant; DNI, dural neurogenic inflammation; i.a., intra-articular; i.g., intraganglionic; SNAP-25, synaptosomal-associated protein 25; TMJ, temporomandibular joint © 2015 The British Pharmacological Society British Journal of Pharmacology (2016) 173 279–291 279 BJP Z Lacković et al. Tables of Links TARGETS LIGANDS GPCRs CGRP CGRP receptor Colchicine Sumatriptan These Tables list key protein targets and ligands in this article which are hyperlinked to corresponding entries in http://www.guidetopharmacology. org, the common portal for data from the IUPHAR/BPS Guide to PHARMACOLOGY (Pawson et al., 2014) and are permanently archived in the Concise Guide to PHARMACOLOGY 2013/14 (Alexander et al., 2013). Introduction Botulinum toxin type A (BoNT/A) blocks the vesicular release of neurotransmitters by proteolytic cleavage of a synaptic protein, synaptosomal-associated protein 25 (SNAP-25). SNAP-25 is a part of the synaptic protein complex which is involved in Ca2+-dependent exocytosis (Kalandakanond and Coffield, 2001; Blasi et al., 1993). This effect of BoNT/A at peripheral nerve endings is the basis of its therapeutic use in a range of neuromuscular (blepharospasm, focal dystonia and spasticity) and autonomic disorders (hyperhidrosis and bladder dysfunction) associated with neuronal over-activity (Dressler, 2013). Based on large clinical studies, pericranially injected BoNT/A has also been approved for the treatment of chronic migraine (Diener et al., 2010). It is widely accepted that migraine headaches involve activation of trigeminal afferents innervating the meningeal blood vessels and dural neurogenic inflammation (DNI) (Moskowitz, 1990; Geppetti et al., 2012; Ramachandran and Yaksh, 2014). We have recently found that the activation of dural afferents, measured as plasma protein extravasation, can be evoked by extracranial pain in the trigeminal region (orofacial formalin-evoked pain and infraorbital nerve constriction-induced trigeminal neuropathy) (Filipović et al., 2012, 2014). The plasma protein extravasation induced by different types of pain was prevented by peripherally injected BoNT/A. The effect of BoNT/A in the cranial dura was associated with axonal transport of the toxin, because its effects were prevented by injection of colchicine directly into the trigeminal ganglion (Filipović et al., 2012). In the present study, we investigated the effects of BoNT/A in a model of trigeminal pain induced by complete Freund’s adjuvant (CFA) injection into the temporomandibular joint (TMJ), a common model of temporomandibular disorders (Harper et al., 2001; Villa et al., 2010). Temporomandibular disorders involve dysfunction of both the TMJ and masticatory muscles, leading to chronic pain (De Rossi et al., 2014). BoNT/A injections into masticatory muscles have been reported to reduce the tenderness and pain in patients suffering from temporomandibular disorders (Sunil Dutt et al., 2015). Severe forms of temporomandibular disorders are highly comorbid with primary headaches – up to 86% of patients suffer from migraine or other primary headaches (Bevilaqua Grossi et al., 2009; Franco et al., 2010). The underlying mechanism of the comorbidity is proposed to be related to extensive innervation of cranial dura by 280 British Journal of Pharmacology (2016) 173 279–291 mandibular branch of trigeminal nerve (Schueler et al., 2013). So far, inflammation of the TMJ has been used preclinically to study the trigeminal sensitization associated with migraine (Villa et al., 2010; Thalakoti et al., 2007). CFA injection into the TMJ induces pain and inflammation leading to peripheral and central sensitization of trigeminal system (Villa et al., 2010). Similarly, by stimulating the TMJ with capsaicin, Thalakoti et al. (2007 found widespread peripheral sensitization in trigeminal ganglion cells. Accordingly, we hypothesized that TMJ pain might provide a suitable model to study trigeminal activation leading to DNI, as well as the mechanism (...truncated)