CGRP overexpression does not alter depression-like behavior in mice

Bimodal functions of calcitonin gene-related peptide in the brain

AIMS

Calcitonin gene-related peptide (CGRP) is a pluripotent neuropeptide crucial for maintaining vascular homeostasis, yet its full therapeutic potential remains incompletely exploited. Within the brain, CGRP demonstrates a distinct bimodal effect, contributing to neuroprotection in ischemic conditions while inducing neuronal sensitization and inflammation in non-ischemic settings. Despite extensive research on CGRP, the absence of a definitive determinant for this observed dichotomy has limited its potential for therapeutic applications in the brain. This review examines the effects of CGRP in both physiological and pathological conditions, aiming to identify a unifying factor that could enhance its therapeutic applicability.

MATERIALS AND METHODS

This comprehensive literature review analyzes the molecular pathways associated with CGRP and the specific cellular responses observed in these contexts. Additionally, the review investigates the psychological implications of CGRP in relation to cerebral perfusion levels, aiming to elucidate its underlying factors.

KEY FINDINGS

Reviewing the literature reveals that, elevated levels of CGRP in non-ischemic conditions exert detrimental effects on brain function, while they confer protective effects in the context of ischemia. These encompass anti-oxidative, anti-inflammatory, anti-apoptotic, and angiogenic properties, along with behavioral normalization. Current findings indicate promising therapeutic avenues for CGRP beyond the acute phases of cerebral injury, extending to neurodegenerative and psychological disorders associated with cerebral hypoperfusion, as well as chronic recovery following acute cerebral injuries.

SIGNIFICANCE

Improved understanding of CGRP's bimodal properties, alongside advancements in CGRP delivery methodologies and brain ischemia detection technologies, paves the way for realizing its untapped potential and broad therapeutic benefits in diverse pathological conditions.

CGRP causes anxiety via HP1γ-KLF11-MAOB pathway and dopamine in the dorsal hippocampus

Calcitonin gene-related peptide (CGRP) is a neuropeptide that causes anxiety behavior; however, the underlying mechanisms remain unclear. We found that CGRP modulates anxiety behavior by epigenetically regulating the HP1γ-KLF-11-MAOB pathway and depleting dopamine in the dorsal hippocampus. Intracerebroventricular administration of CGRP (0.5 nmol) elicited anxiety-like behaviors in open field, hole-board, and plus-maze tests. Additionally, we observed an increase in monoamine oxidase B (MAOB) levels and a concurrent decrease in dopamine levels in the dorsal hippocampus of mice following CGRP administration. Moreover, CGRP increased abundance the transcriptional regulator of MAOB, Krüppel-like factor 11 (KLF11), and increased levels of phosphorylated heterochromatin protein (p-HP1γ), which is involved in gene silencing, by methylating histone H3 in the dorsal hippocampus. Chromatin immunoprecipitation assay showed that HP1γ was recruited to the Klf11 enhancer by CGRP. Furthermore, infusion of CGRP (1 nmol) into the dorsal hippocampus significantly increased MAOB expression as well as anxiety-like behaviors, which were suppressed by the pharmacological inhibition or knockdown of MAOB. Together, these findings suggest that CGRP reduces dopamine levels and induces anxiety-like behavior through epigenetic regulation in the dorsal hippocampus.

Understanding the Biological Relationship between Migraine and Depression

Migraine is a highly prevalent neurological disorder. Among the risk factors identified, psychiatric comorbidities, such as depression, seem to play an important role in its onset and clinical course. Patients with migraine are 2.5 times more likely to develop a depressive disorder; this risk becomes even higher in patients suffering from chronic migraine or migraine with aura. This relationship is bidirectional, since depression also predicts an earlier/worse onset of migraine, increasing the risk of migraine chronicity and, consequently, requiring a higher healthcare expenditure compared to migraine alone. All these data suggest that migraine and depression may share overlapping biological mechanisms. Herein, this review explores this topic in further detail: firstly, by introducing the common epidemiological and risk factors for this comorbidity; secondly, by focusing on providing the cumulative evidence of common biological aspects, with a particular emphasis on the serotoninergic system, neuropeptides such as calcitonin-gene-related peptide (CGRP), pituitary adenylate cyclase-activating polypeptide (PACAP), substance P, neuropeptide Y and orexins, sexual hormones, and the immune system; lastly, by remarking on the future challenges required to elucidate the etiopathological mechanisms of migraine and depression and providing updated information regarding new key targets for the pharmacological treatment of these clinical entities.

Effects of Exercise Training on Executive Functioning in Adults with Depression: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Exercise is a promising nonpharmacological intervention to improve executive function (EF). However, results from randomized trials and meta-analyses examining the effects of exercise on working memory in adults with depression are mixed, and the influence of exercise on EF, as well as the key moderators of the relationship, remain inconclusive.

OBJECTIVE

The present systematic review with meta-analysis examined the influence of exercise interventions on EF in adults with depression, and the influence of key moderating variables.

METHODS

Electronic searches were conducted using Embase, Cochrane Central, Scopus, Ovid MEDLINE, PubMed, Web of Science, China National Knowledge Infrastructure, Wanfang Database, and Weipu Database up to 25 June 2022, and updated on 16 January 2023. Randomized controlled trials (RCTs) examining the effects of exercise training on EF in adults with depression were included. A three-level meta-analysis based on a random-effects model was applied in R. Study quality was assessed using the Physiotherapy Evidence Database (PEDro) scale.

RESULTS

A total of 14 RCTs that evaluated 1201 adults with depression were included. The results indicated that exercise significantly improved global EF [g = 0.180; 95% confidence intervals (CI) = 0.038, 0.323], and the subdomains of working memory (g = 0.182; 95% CI = 0.015, 0.350), cognitive flexibility (g = 0.222; 95% CI = 0.048, 0.395), and reasoning/planning (g = 0.889; 95% CI = 0.571, 1.206). In subgroup analyses, significant improvements in EF were only observed for aerobic exercise (g = 0.203; 95% CI = 0.023, 0.382), moderate-to-vigorous intensity exercise (g = 0.200; 95% CI = 0.022, 0.379), exercise performed three or more times per week (g = 0.207; 95% CI = 0.026, 0.388), in sessions ≤ 60 min (g = 0.173; 95% CI = 0.003, 0.343), and in program durations lasting at least 13 weeks (g = 0. 248; 95% CI = 0.034, 0.462).

CONCLUSIONS

This meta-analysis demonstrates the benefits of exercise training for improving EF and the subdomains of working memory, cognitive flexibility, and reasoning/planning in adults with depression. Future randomized clinical trials are warranted to determine the therapeutic effects of exercise training on EF and cognitive symptoms in depressed patients.

Alpinia oxyphylla Miq. volatile oil ameliorates depressive behaviors and inhibits neuroinflammation in CUMS-exposed mice by inhibiting the TLR4-medicated MyD88/NF-κB signaling pathway

This study aimed to explore the antidepressant effect and underlying mechanism of the Alpinia oxyphylla Miq. volatile oil (AOVO) in mice exposed to chronic unpredictable mild stress (CUMS). C57BL/6 mice were grouped and administered with different dosages of AOVO (0.25, 0.50, 1.00, or 2.00 mL/kg body weight, i.g.), TAK242 (a TLR4 inhibitor, 0.75 mg/kg body weight, i.p.), or TAK242 (0.75 mg/kg body weight, i.p.) + AOVO (0.50 mL/kg body weight, i.g.) for 21 days. Depression-like symptoms in the mice were then evaluated through their body weight gain (BW), the open field test (OFT), the sucrose preference test (SPT), the novelty-suppressed feeding test (NSFT), and forced swimming test (FST). The concentrations of interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), and 5-hydroxytyrptamine (5-HT) in the mice were determined using ELISA kits. Hematoxylin and eosin (HE) dying were performed for histopathological examination. The expression of inflammatory proteins was assessed through western blotting (WB) and immunofluorescence staining. AOVO was found to improve the behavioral indexes of CUMS-exposed mice behavioral and synergize TAK242 to mitigate both their depressive symptoms and neuroinflammation. Moreover, AOVO was found to inhibit the hippocampal damage, decrease inflammatory cytokines (Reduced IL-1β, IL-6, and TNF-α by 19.97 %, 22.87 %, and 24.13 %, respectively), and downregulate the expression of TLR4/MyD88/NF-κB signaling pathway-related proteins in the hippocampus of CUMS-exposed mice (Reduced TLR4, MyD88, and NF-κB by 46.14 %, 42.48 %, and 38.08 %, respectively). These findings demonstrate that AOVO can ameliorate depressive behaviors and mitigate neuroinflammation in the CUMS-exposed mice via suppressing the TLR4-medicated MyD88/NF-κB signaling pathway.

Galcanezumab for the treatment of chronic migraine and medication overuse headache: Real-world clinical evidence in a severely impaired patient population

BACKGROUND

Galcanezumab is a monoclonal antibody acting against the calcitonin gene-related peptide approved for the preventive treatment of migraine. The aim of this article is to explore its effectiveness and safety of galcanezumab in chronic migraine (CM) with medication overuse-headache (MOH).

METHODS

Seventy-eight patients were consecutively enrolled at the Modena headache center and followed up for 15 months. Visits were scheduled every 3 months, and the following variables were collected: the number of migraine days per month (MDM); the painkillers taken per month (PM); the number of days per month in which the patient took, at least, one painkiller; the six-item headache impact test; and the migraine disability assessment questionnaire (MIDAS) score. Demographic features of the analyzed sample were collected at the baseline and adverse events (AEs) were collected at every visit.

RESULTS

After 12 months, galcanezumab significantly reduced the MDM, the PM, the number of days on medication, the HIT-6 as well as the MIDAS scores (all p < .0001). The greatest amelioration was obtained in the first trimester of treatment. A higher MDM, a higher NRS score at the baseline, and a higher number of failed preventive treatments negatively predict the CM relief at the year of treatment. No serious AEs were registered and only one drop-out was due to AE.

CONCLUSIONS

Galcanezumab is effective and safe for the treatment of patients affected by CM and MOH. Patients with a higher impairment at the baseline may found less benefits with galcanezumab.

Adolescent binge-like alcohol exposure dysregulates NPY and CGRP in rats: Behavioural and immunochemical evidence

Alcohol binge drinking during adolescence impacts affective behaviour, possibly impinging on developing neural substrates processing affective states, including calcitonin gene-related peptide (CGRP) and neuropeptide Y (NPY). Here, we modelled binge-like alcohol exposure in adolescence, by administering 3.5 g/kg alcohol per os, within 1 h, to male adolescent rats every other day, from postnatal day 35 to 54. The effects on positive and negative affective behaviour during abstinence were explored including: consummatory behaviour and weight gain; social behaviour in the modified social interaction test; thermal nociception in the tail-flick test; psychosocial stress coping in the resident-intruder paradigm. Moreover, CGRP and NPY levels were evaluated in functionally relevant brain regions. Our data shows that binge-like intermittent alcohol administration during adolescence decreased weight gain, social preference and motivation, nociception, and active psychosocial stress coping during abstinence. In addition, intermittent alcohol-exposed rats displayed increased expression of CGRP and NPY in the prefrontal cortex and nucleus accumbens; decreased NPY levels in the amygdala; opposite changes in CGRP levels in the hypothalamus and brainstem. Overall, our data shows that adolescent binge-like alcohol exposure, through the allostatic load of alternate intoxication and withdrawal, produces long-term consequences in sensory and affective processes and dysregulated complementary neuropeptidergic systems. Thus, neuropeptide-targeted interventions hold promising potential for addressing negative affect during prolonged withdrawal in young subjects.

P2RY12 Increased Neuroinflammation to Accelerate Depression-like Behaviors by the NLPR3 Inflammasome

INTRODUCTION

Depression is a class of important mental illness, which has become a severe health problem perplexing the world due to its high morbidity rate, high disability rate, and great disease burden. This study aimed to evaluate the role and possible mechanisms of P2RY12 in the depression-like behaviors model.

METHODS

Serum samples of patients with depression-like behaviors were used to analyze the expression of P2RY12. Models of mice were given LPS via intraperitoneal injection for 7 days. Behavioral tests were executed in this experiment.

RESULTS

The expression of P2RY12 in models of depression-like behaviors or mice with depression- like behaviors were induced. The inhibition of P2RY12 presents depression-like behaviors and reduces inflammation in the model of depression-like behaviors. P2RY12 induced NLRP3 expression and suppressed NLRP3 ubiquitination in a model of depression-like behavior. The inhibition of NLRP3 reduced the effects of P2RY12 in mice model of depression-like behaviors. The regulation of NLRP3 controlled the effects of the P2RY12 in vitro model of depression-like behaviors.

CONCLUSION

We conclude that P2RY12 increased neuroinflammation to accelerate depression-like behaviors by NLPR3 inflammasome, providing novel information for the treatment of depressionlike behaviors.

Lactobacillus paragasseri OLL2809 Improves Depression-Like Behavior and Increases Beneficial Gut Microbes in Mice

Lactobacillus paragasseri OLL2809 is a probiotic bacterial strain isolated from healthy human feces. While OLL2809 has been studied for its immunomodulatory activities, its effect on depressive-like behaviors remains unclear. In this study, we used a mouse model of social defeat stress (SDS) to investigate whether oral administration of OLL2809 ameliorates depressive-like behavior. C57BL6 male mice were administered OLL2809 for 2 weeks following a 4-week period of SDS. Although OLL2809 did not affect serum corticosterone levels, it ameliorated depression-like behaviors, and it induced neurite outgrowth in the hippocampal dentate gyrus. The 16S rRNA amplicon sequence analyses revealed that family level gut microbiota composition was affected by stress and OLL2809 administration. Additionally, Akkermansia muciniphila, Bifidobacterium, and Lactobacillus were significantly increased by OLL2809 treatment. LEfSe analysis suggested that the antidepressive effect of OLL2809 may be mediated by increases in other microorganisms, such as Erysipelotrichaceae uncultured. Our findings suggest that L. paragasseri OLL2809 may have potential in microbiome therapeutics.