The research focuses on the secretory mechanism and pathophysiological actions of mast cells. Diseases investigated include: atopic dermatitis, arthritis, autism, coronary artery inflammation, interstitial cystitis, migraines and multiple sclerosis. These diseases worsen by stress and we have identified that mast cells both contain and respond to stress hormones. The techniques used include molecular biology, cell biology, and various microscopic techniques, as well as animal models for the target diseases in which mast cells are involved.
1. Pathophysiology of mast cells in mastocytosis and in neuroimmunoendocrine disorders. Mast cells are known for their involvement in allergic reactions, but we were the first to show that they are also necessary to inititate inflammation, thus participating in inflammatory diseases that worsen by stress, such as autism, cancer, chronic fatigue syndrome, interstitial cystitis, migraine headaches, psoriasis and multiple sclerosis. We have developed in vivo and in vitro models for these diseases and we are studying neurohormonal activation of mast cells. The only plausible way to explain how mast cells can participate in so many diverse processes is their ability to secrete distinct chemicals relative for different pathophysiological settings (see below).
2. Molecular events involved in mast cell stimulus-secretion coupling, especially with their ability to release mediators selectively without degranulation. Mast cells are typically activated by immunoglobulin E and antigen, a process that leads to an explosive release of over 20 biologically active molecules (some of which are presorted in some 500 secretory grqnules, wile others are synthesized during activation) through a process called degranulation or exocytosis. However, we were the first to show that mast cells can also respond to non-allergic triggers and release mediators selectively, without degranulation. We specifically reported that the inflammatory cytokine IL-1 can induce selective release of the also inflammatory cytokine IL-6, that the stress hormone corticotropin-releasing hormone (CRH) can induce selective release of vascular endothelial growth factor (VEGF), and IL-33 augments substance P-induced VEGF release. We are currently studying the regulation of CRH receptor expression and function on human cultured mast cells and the effects of their respective activation on allergic stimulation.
3. Mast cells have the ability to superstimulate activated T cvells; mofeover, the mast cell mediators IL-6 and TGFbeta participate in the maturation of Th17 cells, which are increasingly imlplicated in autoimmune diseases such as multiple sclerosis and psoriasis. Par of this process requires cell-to-cell contact, but also TNF secretion. We are investigating how IL-33 and SP (see above) could drive mast cells to participate in Th1-type of diseases and how such interactions may be interrupted for therapeutic purposes.
4. Regulation of mast cell secretion by the mitochondrial uncoupling protein 2 (UCP2) and mitochondrial dynamics. We showed for the first time that there is an inverse relationship between UCP2 expression and mast cell secretion. We also showed for the firtst time that mast cell degranulation, but not selective release of tumor necrosis factor (TNF), is associated with mitochondrial fission and relocation from perinuclear localization to cell-widespread distribution.
5. Antisecretory and antiproliferative function of the 78 kD mast cell phosphoprotein. We sequenced this protein and showed that, in its phosphorylated state, it inhibits mast cell secretion and tumor growth. We are investigating the regulation of its expression, identification of the phosphorylated sites and molecules that could increase and sustain the phosphorylated state of this protein.
6. Anti-allergic and anti-inflammatory actions of some natural polyphenolic flavonoids. We are investigating the mechanism of action of the select flavnoids luteolin and quercetin, their formulation in ways that increases their absorption, as well as their blood concentrations in order to achieve maximal effective levels. Such compounds could serve as anti-allergic, anti-inflammatory and anticancer drugs.
7. Role of neonatal mast cell activation in the pathogenesis of autism. We reported that the prevalence of autism is ten times higher (1/10 children) in patients with mastocytosis than the general population (1/100 children). What makes this finding even more impressive is that mastocytosis is a rare disease occurring in 1/4000 children and is characterized by many hypersensitive mast cells in many tissues; once would, therefore, expect that the combined prevalence would have been 1/100x1/4,000=1/400,000 and not 1/10 children! We also found that the neuropeptide neurotensin, which is a pogtent mast cxell trigger, is statistically much higher in the serum of autistic patients. We are investigating the presence of additional biomarkers in the serum of autistic patients, the effect of stress (CRH) and environmental (mercury) triggers on the action of neurotensin on mast cells, as well as the potential benefit of a flavonoid formulation for the treatment of autism.
What is a true “mast cell stabilizer”?
In spite of anecdotal reports and websites such as
NEITHER ketotifen nor cromolyn are true mast cell stabilizers as they DO NOT BLOCK inflammatory cytokine release.
Ketotifen IS a histamine-1 receptor antagonist that is also a weak inhibitor of histamine and prostaglandin release through an unknown mechanism. The additional benefit of ketotifen over other antihistamines is that it blocks the actions of eosinophils usually involved in allergies and particularly in eosinophilic esophagitis/gastroenteritis.
Disodium cormoglycate (cromolyn) was thought to be a “mast cell stabilizer” because it blocked rodent mast cells, but is is a very WEAK inhibitor of HUMAN mast cells, and like ketotifen, it inhibits histamine and prostaglandin release to some extent, but NOT inflammatory cytokine release, again through an unknown mechanism.
Please see the papers below that indicate that quercetin is more potent than cromolyn, and another paper using cromolyn cream showing that it block itch (pruritus) by acting on sensory nerve endings and does NOT inhibit skin mast cells. Other papers mentioned below clearly indicate the quercetin and luteolin can block human mast cell release of the most important allergic and inflammatory molecules in response to different allergic and non-immune triggers.
NeuroProtek contains luteolin and quercetin, both of which have been shown to block release of every mediator studies from mast cells. The problem is to get enough of these to be absorbed orally. Nevertheless, NP can be given together with either ketotifen and/or cromolyn to the extent that the latter are helpful in some patients.
A case series of a Luteolin formulation (neuroprotek) in children with autism spectrum disorders. <http://www.ncbi.nlm.nih.gov/pubmed/22697063>
Theoharides TC, Asadi S, Panagiotidou S.
Int J Immunopathol Pharmacol. 2012 Apr-Jun;25(2):317-23.
Quercetin is more effective than cromolyn in blocking human mast cell cytokine release and inhibits contact dermatitis and photosensitivity in humans. <http://www.ncbi.nlm.nih.gov/pubmed/22470478>
Weng Z, Zhang B, Asadi S, Sismanopoulos N, Butcher A, Fu X, Katsarou-Katsari A, Antoniou C, Theoharides TC.
PLoS One. 2012;7(3):e33805. Epub 2012 Mar 28.
Topical sodium cromoglicate relieves allergen- and histamine-induced dermal pruritus. <http://www.ncbi.nlm.nih.gov/pubmed/19785618>
Vieira Dos Santos R, Magerl M, Martus P, Zuberbier T, Church MK, Escribano L, Maurer M.
Br J Dermatol. 2010 Mar;162(3):674-6. Epub 2009 Sep 24.
Luteolin and thiosalicylate inhibit HgCl(2) and thimerosal-induced VEGF release from human mast cells. <http://www.ncbi.nlm.nih.gov/pubmed/21244751>
Asadi S, Zhang B, Weng Z, Angelidou A, Kempuraj D, Alysandratos KD, Theoharides TC.
Int J Immunopathol Pharmacol. 2010 Oct-Dec;23(4):1015-20.
Inhibitory effect of quercetin on tryptase and interleukin-6 release, and histidine decarboxylase mRNA transcription by human mast cell-1 cell line. <http://www.ncbi.nlm.nih.gov/pubmed/17191106>
Kempuraj D, Castellani ML, Petrarca C, Frydas S, Conti P, Theoharides TC, Vecchiet J.
Clin Exp Med. 2006 Dec;6(4):150-6.
Flavonols inhibit proinflammatory mediator release, intracellular calcium ion levels and protein kinase C theta phosphorylation in human mast cells. <http://www.ncbi.nlm.nih.gov/pubmed/15912140>
Kempuraj D, Madhappan B, Christodoulou S, Boucher W, Cao J, Papadopoulou N, Cetrulo CL, Theoharides TC.
Br J Pharmacol. 2005 Aug;145(7):934-44.
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T.C. Theoharides Ph.D., M.D.
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