REVIEW | doi:10.20944/preprints202210.0083.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: epigenetics; TRP channels; TRPA1; pain transmission; neuropathic pain; neurogenic inflammation; migraine; DNA methylation; histone modification; micro RNA
Online: 7 October 2022 (15:21:34 CEST)
Background: Transient receptor potential cation channel subfamily A member 1 (TRPA1) is expressed in trigeminal neurons and brain regions important in migraine pathogenesis and is activated by many migraine triggers. Epigenetic regulation of TRPA1 expression is important in pain transmission and neurogenic inflammation.Findings: TRPA1 channels change noxious stimuli into pain signals with the involvement of epigenetic regulation, including DNA methylation, histone modifications, and effects of micro RNAs (miRNAs) and long non-coding RNAs. TRPA1 may change epigenetic profile of many pain-related genes as it may modify enzymes establishing the epigenetic profile and expression of non-coding RNAs. TRPA1 may induce the release of calcitonin gene related peptide (CGRP), from trigeminal neurons and dural tissue. Therefore, epigenetic regulation of TRPA1 may play a role in efficacy and safety of anti-migraine therapies targeting TRP channels and CGRP. TRPA1 is also involved in neurogenic inflammation, important in migraine. The fundamental role of TRPA1 in inflammatory pain transmission may be epigenetically regulated. Conclusions: Epigenetic connections of TRPA1 may play a role in efficacy and safety of anti-migraine therapy targeting TRP channels or CGRP and they should be further explored for efficient and safe antimigraine treatment.
REVIEW | doi:10.20944/preprints202308.0760.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: abdominal migraine; tryptophan metabolism; kynurenine; gut-brain axis; metabolic treatment in migraine
Online: 9 August 2023 (09:38:57 CEST)
Background: Abdominal migraine (AM) is a clinical diagnosis specified by Rome IV and ICHD III as a functional gastrointestinal disease (FGID) and a migraine associated syndrome, respectively. AM is undiagnosed and undertreated, and thus far the FDA has not approved any drug for AM treatment. We and others showed that changes in the kynurenine (KYN) pathway of tryptophan (TRP) metabolism played an important role in the pathogenesis and treatment of FIGDs. Changes in the KYN pathway were shown in migraine. Findings: Abdominal migraine reflects impairments in communication within the gut-brain axis. Treatment approaches have not been sufficiently documented and are based on experience of physicians, presenting personal rather than evidence-based practice and including efficacy of some drugs used in adult migraine. Non-pharmacological treatment of AM is aimed preventing or ameliorating AM triggers. Modulations within the KYN pathway of TRP metabolism induced by changes in TRP content in the diet, may ameliorate FGIDs and support their pharmacological treatment. Pharmacological manipulations of brain KYNs in animals have brought promising results for clinical applications. Conclusions: In conclusion, controlled placebo-based clinical trials with dietary manipulation to adjust the amount of the product of the KYN pathway of TRP metabolism are justified in children and adolescents with AM. Further preclinical studies are needed to establish details of these trials.
ARTICLE | doi:10.20944/preprints202307.1220.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: age-related macular degeneration; aging retina; peroxisome proliferator-activated receptor gamma coactivator 1-alpha; PGC-1 AMD; cellular senescence; autophagy; oxidative stress
Online: 18 July 2023 (11:09:42 CEST)
We previously showed that mice with knockout in the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) gene encoding the PGC-1a protein and nuclear factor erythroid 2 like 2 (NFE2L2) gene, showed some features of the age-related macular degeneration (AMD) phenotype. To further explore the mechanism behind the involvement of PGC-1a in AMD pathogenesis we used young (3-month) and old (12-month) mice with knockout in the PPARGC1A gene and age-matched wild-type (WT) animals. An immunohistochemical analysis showed age-dependent different expression of markers of oxidative stress defense, senescence and autophagy in the retinal pigment epithelium of KO animals as compared with their WT counterparts. Multivariate inference testing showed that senescence and autophagy proteins had the greatest impact on the discrimination between KO and WT 3-month animals, but proteins of antioxidant defense also contributed to that discrimination. A bioinformatic analysis showed that PGC-1a might coordinate the interplay between genes encoding proteins involved in antioxidant defense, senescence and autophagy in the aging retina. These data support importance of PGC-1a in AMD pathogenesis and confirm the utility of mice with PGC-1a knockout as an animal model to study AMD pathogenesis.