Inhibition of tryptase release from human colon mast cells by protease inhibitors

Screening of Prospective Plant Compounds as H1R and CL1R Inhibitors and Its Antiallergic Efficacy through Molecular Docking Approach

Allergens have the ability to enter the body and cause illness. Leukotriene is the widespread allergen which could stimulate mast cells to discharge histamine which causes allergy symptoms. An effective strategy for treating leukotriene-induced allergy is to find the inhibitors of leukotriene or histamine activity from phytochemicals. For this purpose, a library of 8,500 phytochemicals was generated using MOE software. The structures of histamine-1 receptor and cysteinyl leukotriene receptor-1 were predicted by the homology modeling method through the SWISS model. The phytochemicals were docked with predicted structures of histamine-1 and cysteinyl leukotriene receptor-1 in MOE software to determine the binding affinity of the phytochemicals against the targets. Moreover, chemoinformatics properties and ADMET of phytochemicals were assessed to find the drug likeness behavior of compounds. Compound ID 10054216 has the lowest $S$ -score value for H-1 receptor that is -18.9186 kcal/mol which is lower than the value of standard -15.167 kcal/mol. The other compounds 393471, 71448939, 10722577, and 442614 also showed good $S$ -score values than the standard. Moreover, compound ID 11843082 has the lowest $S$ -score value for CL1R that is -15.481 kcal/mol which is lower than the value of standard -12.453 kcal/mol. The other compounds 72284, 5282102, 66559251, and 102506430 also showed good $S$ -score values than the standard. In this research article, we performed molecular docking to find the best inhibitors against H1R and CL1R and their antiallergic efficacy. This in silico knowledge will be helpful in near future for the design of novel, safe, and less costing H-1 receptor and CL1R inhibitors with the aim to improve human life quality.

Chymase inhibition as a pharmacological target: a role in inflammatory and functional gastrointestinal disorders?

Chymase has been extensively studied with respect to its role in the pathophysiology of cardiovascular disease, and is notable for its role in the generation of angiotensin II, a mediator crucial in vascular remodelling. However, in more recent years, an association between chymase and several inflammatory diseases, including gastrointestinal (GI) disorders such as inflammatory bowel diseases (IBD) have been described. Such studies, to date, with respect to IBD at least, are descriptive in the clinical context; nonetheless, preclinical studies implicate chymase in the pathogenesis of gut inflammation. However, studies to elucidate the role of chymase in functional bowel disease are in their infancy, but suggest a plausible role for chymase in contributing to some of the phenotypic changes observed in such disorders, namely increased epithelial permeability. In this short review, we have summarized the current knowledge on the pathophysiological role of chymase and its inhibition with reference to inflammation and tissue injury outside of the GI tract and discussed its potential role in GI disorders. We speculate that chymase may be a novel therapeutic target in the GI tract, and as such, inhibitors of chymase warrant preclinical investigation in GI diseases.

Efficacy of alpha1-antitrypsin augmentation therapy in conditions other than pulmonary emphysema

Up to now alpha 1-antitrypsin (AAT) augmentation therapy has been approved only for commercial use in selected adults with severe AAT deficiency-related pulmonary emphysema (i.e. PI*ZZ genotypes as well as combinations of Z, rare and null alleles expressing AAT serum concentrations <11 μmol/L). However, the compassionate use of augmentation therapy in recent years has proven outstanding efficacy in small cohorts of patients suffering from uncommon AAT deficiency-related diseases other than pulmonary emphysema, such as fibromyalgia, systemic vasculitis, relapsing panniculitis and bronchial asthma. Moreover, a series of preclinical studies provide evidence of the efficacy of AAT augmentation therapy in several infectious diseases, diabetes mellitus and organ transplant rejection. These facts have generated an expanding number of medical applications and patents with claims for other indications of AAT besides pulmonary emphysema. The aim of the present study is to compile and analyze both clinical and histological features of the aforementioned published case studies and reports where AAT augmentation therapy was used for conditions other than pulmonary emphysema. Particularly, our research refers to ten case reports and two clinical trials on AAT augmentation therapy in patients with both AAT deficiency and, at least, one of the following diseases: fibromyalgia, vasculitis, panniculitis and bronchial asthma. In all the cases, AAT was successfully applied whereas previous maximal conventional therapies had failed. In conclusion, laboratory studies in animals and humans as well as larger clinical trials should be, thus, performed in order to determine both the strong clinical efficacy and security of AAT in the treatment of conditions other than pulmonary emphysema.

Abnormal overexpression of mastocytes in skin biopsies of fibromyalgia patients

Formalin-fixed, paraffin-embedded skin tissue sections were collected from a matched cohort of 63 fibromyalgia syndrome (FMS) patients and 49 volunteers from the general population with both alpha1-antitrypsin (AAT) normal and deficiency variants. These tissues were examined for the expression of the broad-spectrum inhibitor AAT, the serine proteinases elastase and tryptase, the proinflammatory cytokines MCP-1 and TNFα, the endothelium biomarker VEGF, and the inflammation/nociception-related receptor PAR(2). The most relevant finding of the study was a significantly increased number of mast cells (MCs) in the papillary dermis of all FMS patients (greater than or equal to five to 14 per microscopic high power field) compared to zero to one in controls (p < 0.001). MCs strongly stained with tryptase, AAT and PAR(2) antibodies, exhibited a spindle-like shape and were uniformly distributed around blood vessels and appendages. MCP-1 and VEGF expressed weak/moderate positivity in most samples, with a higher expression in controls than in FMS patients (p < 0.001 and 0.051, respectively). No differences in elastase and TNFα were found between both groups. Moreover, no histological differences were found between samples from AAT deficiency and normal AAT phenotypes. Our results indicate that FMS is a MC-associated condition. MCs are present in skin and mucosal surfaces throughout the human body, and are easily stimulated by a number of physical, psychological, and chemical triggers to degranulate, releasing several proinflammatory products which are able to generate nervous peripheral stimuli causing CNS hypersensitivity, local, and systemic symptoms. Our findings open new avenues of research on FMS mechanisms and will benefit the diagnosis of patients and the development of therapeutics.

Na-Tosyl-Phe chloromethyl ketone prevents granule movement and mast cell synergistic degranulation elicited by costimulation of antigen and adenosine

Adenosine has been shown to enhance mast cell degranulation when added together with an antigen. Such augmentation of mast cell activation is relevant to exacerbation of allergic asthma symptoms. Na-Tosyl-Phe chloromethyl ketone (TPCK) is a chymotrypsine-like chymase inhibitor, which has anti-inflammatory properties. In this study, we investigated the effects of TPCK on mast cell synergistic degranulation induced by antigen and adenosine. Here, we report that TPCK almost completely suppressed enhanced degranulation by inhibiting granule movement. Consistent with this, intraperitoneal administration of TPCK resulted in significant amelioration of passive cutaneous anaphylaxis in mice. Furthermore, we demonstrated that TPCK completely inhibited Thr308 phosphorylation of protein kinase B in mast cells stimulated with antigen and adenosine. These results provide a novel action of TPCK for the prevention of mast cell degranulation induced by antigen and adenosine.

α1-Antitrypsin and fibromyalgia: new data in favour of the inflammatory hypothesis of fibromyalgia

alpha1-Antitrypsin (AAT) circulates in high serum concentrations, and impregnates most body tissues. AAT has a broad anti-inflammatory spectrum, and modulates most inflammatory reactions occurring in human body. Recently, a possible relationship between AAT deficiency (AAT-D) and fibromyalgia (FM) has been raised, with the finding that intravenous infusions of purified human AAT efficiently controlled FM symptoms in two patients with severe hereditary AAT-D. On the other hand, functional magnetic resonance imaging has detected a significant greater activity in pain sensitive areas of the brain in patients with FM, in response to cutaneous stimuli, providing further evidence for a physiological explanation for FM pain. In recent studies abnormal profiles of inflammation markers in serum and biopsies have been found in FM patients. Since most of these inflammation mediators can be inhibited by AAT, these observations would suggest that at least a subset of the FM syndrome could be related to an inflammatory process, possibly due to an imbalance between inflammatory and anti-inflammatory substances, in the soft body tissues. Future directions of research would be: (1) to develop epidemiological studies to determine the gene frequency of AAT deficiency alleles in FM patients; (2) implementation of a double-blind placebo-controlled clinical trial to determine the specific role of AAT augmentation therapy in AAT-D patients with FM; (3) identification of specific laboratory markers for diagnostic and clinical evaluation purposes in FM; (4) application of the newest medical imaging techniques for diagnosis; and (5) identification of genetic, familial, and environmental risk factors suspected to participate in the FM syndrome development.