headache

Development of a multi-modal mouse model of cluster headache

PROJECT SUMMARY / ABSTRACT Cluster headache (CH), which affects about 1 in 1,000 people, is a severe and debilitating primary headache disorder characterized by repeated attacks occurring in clusters over weeks or months. CH has clearly defined features: severe pain (worse than childbirth), facial autonomic changes (such as a watery eye), restlessness, and a striking circadian pattern of attacks (at the same time each day like clockwork in approximately 70.5% of patients). CH also has a well-defined pathophysiology of 3 systems: the trigeminovascular pain system, the autonomic nervous system, and the hypothalamic system (in particular the posterior hypothalamus, the first brain area activated during an attack). Despite the well-known features and systems involved in CH, no disease- specific treatments are available: all CH treatments are repurposed medications from other diseases. This lack of CH-specific treatments is due in large part to the lack of a viable animal model that faithfully recapitulates the aforementioned CH features. To develop a specific animal model for CH, we previously studied a trigeminovascular headache model (repeated nitroglycerin injections), and discovered a circadian pattern of pain responses that reflects the clockwork-like pattern of attacks in CH patients. Furthermore, our analysis also identified a recently discovered CH modifier gene Mertk (MER proto-oncogene, tyrosine receptor kinase) to be highly rhythmically expressed in the trigeminal ganglion. Deletion of Mertk (Mertk-KO) altered the normal circadian rhythm of pain sensitivity by increasing pain sensitivity over 24 hours. Finally, activation of the posterior hypothalamus (via c-Fos staining) was observed after NTG administration in wild-type mice. Based on these exciting preliminary findings, we hypothesize that a combination of trigeminovascular (nitroglycerin), genetic (Mertk-KO), and hypothalamic (direct optogenetic activation of the posterior hypothalamus) manipulations will generate the first multi-modal animal model of CH. In Aim 1 (the R61 phase), we will determine the contributions of each aspect of our combined model, alone or in combination (a 4x2 grid of NTG or control, Mertk KO mouse or wild-type control, and optogenetic injection or control). Our milestone for progression to the R33 phase will be significant differences in at least two pain behaviors in our model compared to controls. In Aims 2 and 3 (the R33 phase), we will validate our model through face validity (lacrimation and restlessness), construct validity (CGRP, PACAP, and VIP in the trigeminal ganglion and hypothalamus), and predictive validity (ability of first-line and new treatments to ameliorate the pain behaviors of our model). This project is highly significant and innovative, addressing a profound need for a specific and comprehensive animal model for this devastating yet understudied disease. With the unique combination of complementary expertise in CH (laboratory and clinical), circadian biology, pharmacology, optogenetics and pain, we are ideally suited to generate this combined CH model with the goal of providing insights into CH pathophysiology and developing novel therapeutics.

Untitled Seminar

Post-traumatic headache

Concussion (mild traumatic brain injury) affects approximately 50 million people annually. Headache is the most common symptom after concussion and persists in up to 50% of those affected for at least one-year. The biological underpinnings of and the efficacy and tolerability of treatments for post-traumatic headache has historically received little attention. While treatment in clinical practice is mostly directly at the underlying phenotype of the headache, persistent post-traumatic headache is considered to be less responsive to treatments used to treat migraine or tension-type headache. Over the past several years, significant pre-clinical research has begun to elucidate the mechanism(s) involved in the development of post-traumatic headache, and a concerted effort to evaluate the efficacy of selected treatments for persistent post-traumatic headache has begun. This presentation will review the epidemiology, pathophysiology, and emerging data on the prevention and treatment of post-traumatic headache.

Emerging therapeutic targets for migraine

Migraine is the third most prevalent disease worldwide and is estimated to affect upwards of 14% of the population. Our lab has used novel preclinical models to identify the delta opioid receptor (DOR) as a therapeutic target for multiple headache disorders, including migraine. We have also investigated the relationship between DOR with the pro-migraine peptide, CGRP. There is regional variation between the co-expression of DOR with CGRP or its receptor in the trigeminal complex. This work indicates that DOR agonists can moderate both CGRP release and signaling, thus regulating pro-migraine effects at two different levels. Recent work in our lab has also explored how cytoarchitectural changes in pain processing regions are critical for the maintenance of the chronic migraine state. We show that there is decreased neuronal complexity in two different models of migraine, and that restoration of tubulin dynamics, directly by HDAC6 inhibitor or indirectly by CGRP receptor antagonist, can inhibit migraine-associated symptoms. These studies provide fundamental information on how cytoskeletal dynamics are altered in chronic migraine, and form the basis for the development of HDAC6 inhibitors for headache treatment.

Migraine: a disorder of excitatory-inhibitory balance in multiple brain networks? Insights from genetic mouse models of the disease

Migraine is much more than an episodic headache. It is a complex brain disorder, characterized by a global dysfunction in multisensory information processing and integration. In a third of patients, the headache is preceded by transient sensory disturbances (aura), whose neurophysiological correlate is cortical spreading depression (CSD). The molecular, cellular and circuit mechanisms of the primary brain dysfunctions that underlie migraine onset, susceptibility to CSD and altered sensory processing remain largely unknown and are major open issues in the neurobiology of migraine. Genetic mouse models of a rare monogenic form of migraine with aura provide a unique experimental system to tackle these key unanswered questions. I will describe the functional alterations we have uncovered in the cerebral cortex of genetic mouse models and discuss the insights into the cellular and circuit mechanisms of migraine obtained from these findings.

Pediatric Migraine: Who, What, When, Where

This talk will address important aspects of pediatric migraine research, including: 1) Who is affected by pediatric migraine? 2) What does pediatric migraine look like, and what does a clinician need to do to reach a migraine diagnosis in a child? 3) When does pediatric migraine begin, and how might it present clinically before it presents as headache (e.g., infant colic, benign paroxysmal torticollis, cyclic vomiting syndrome etc.) 4) Where does responsibility for decreasing pediatric migraine frequency rest? What is society's role in preventing migraine in young people?

Cluster Headache: Improving Therapy for the Worst Pain Experienced by Humans

Cluster headache is a brain disorder dominated clinically by dreadful episodes of excruciating pain with a circadian pattern and most often focused in bouts with circannual periodicity. As we have understood its neurobiology new therapies, including those directed at calcitonin gene-related peptide, are helpful improve the lives of sufferers.

Migraine Headache: the revolution and its evolution

This seminar will focus on the extraordinary shift in migraine research during the last 4 decades with the discovery of the trigeminovascular system (TVS) and it’s major impact on pathophysiology and treatment.  Compelling evidence supporting the importance of TVS, cortical spreading depression and parameningeal inflammation will be explored as will the implications of newly discovered microvascular channels within the meninges on an attack.

New Frontiers in Understanding and Treating Migraine Headaches

In this presentation I will describe how the CGRP project started and culminated in the development of gepants and mAbs for successful therapy. The outstanding question regarding the preponderance of female migraineurs also remains. I will present views on the reason behind this and suggest that understanding the hormonal influence will pave the way to alleviating hormone related migraine.

40 years of headache research

Lifelong devotion to headache research has led to many discoveries. First a series of studies of brain blood flow during attacks of migraine. The results showed changes compatible with cortical spreading depression in migraine without aura effectively negating the then prevailing vasospastic/ischemic theory. In migraine without aura no changes in brain blood flow. This difference was crucial for the separation of migraine with aura and migraine without aura in the first and subsequent editions of the international headache classification headed by me. Then a human migraine provocation model that has elucidated the molecular mechanisms of migraine. Successively we showed in series of papers the importance of nitric oxide, histamine, CGRP, PACAP and prostanoids. Therapeutic effectiveness of antagonizing these provokers by tonabersat, L-NMMA, CGRP receptor antagonists and monoclonal antibodies and of NSAIDs. Present and future attempts to put all these signaling mechanisms into a framework but it is not easy

PACAP at the crossroads: Interplay and synergy with other neuropeptides in headache disorders

FENS Forum 2024