The Role of Cyclic Adenosine Monophosphate (cAMP) in Modulating Glucocorticoid Receptor Signaling and Its Implications on Glucocorticoid-Related Collagen Loss

Exploring the interaction between the gut microbiota and cyclic adenosine monophosphate-protein kinase A signaling pathway: a potential therapeutic approach for neurodegenerative diseases

The interaction between the gut microbiota and cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling pathway in the host's central nervous system plays a crucial role in neurological diseases and enhances communication along the gut-brain axis. The gut microbiota influences the cAMP-PKA signaling pathway through its metabolites, which activates the vagus nerve and modulates the immune and neuroendocrine systems. Conversely, alterations in the cAMP-PKA signaling pathway can affect the composition of the gut microbiota, creating a dynamic network of microbial-host interactions. This reciprocal regulation affects neurodevelopment, neurotransmitter control, and behavioral traits, thus playing a role in the modulation of neurological diseases. The coordinated activity of the gut microbiota and the cAMP-PKA signaling pathway regulates processes such as amyloid-β protein aggregation, mitochondrial dysfunction, abnormal energy metabolism, microglial activation, oxidative stress, and neurotransmitter release, which collectively influence the onset and progression of neurological diseases. This study explores the complex interplay between the gut microbiota and cAMP-PKA signaling pathway, along with its implications for potential therapeutic interventions in neurological diseases. Recent pharmacological research has shown that restoring the balance between gut flora and cAMP-PKA signaling pathway may improve outcomes in neurodegenerative diseases and emotional disorders. This can be achieved through various methods such as dietary modifications, probiotic supplements, Chinese herbal extracts, combinations of Chinese herbs, and innovative dosage forms. These findings suggest that regulating the gut microbiota and cAMP-PKA signaling pathway may provide valuable evidence for developing novel therapeutic approaches for neurodegenerative diseases.

Novel insights into self-defense function of anammox sludge under magnesium ions (Mg2+) stress based on Mg2+ transport system

Magnesium ion (Mg2+) plays an important role in the accumulation and stability of anaerobic ammonium-oxidizing bacteria (AnAOB). In this study, the response of anammox sludge to Mg2+ was comprehensively investigated by performance evaluation and metagenomics analysis. Appropriate Mg2+ (0.8 mmol/L) could improve the nitrogen removal performance, AnAOB activity, and the synthesis potential of some hydrophobic substances, while high Mg2+ (>1.6 mmol/L) has a negative effect. Meanwhile, Mg2+ transmembrane transport theory was introduced to reveal the response principle of AnAOB to Mg2+ from a novel insight. AnAOB may have a self-defense function based on the PhoQ/PhoP-MgtAB system. Low extracellular Mg2+ will activate this function to enhance Mg2+ influx, thereby improving the intracellular metabolism of AnAOB. Excessive Mg2+, however, dormant this function and induces Mg2+ efflux, which may decrease the intracellular Mg2+ and thus affect AnAOB metabolism. These findings provide valuable references for the Mg2+ regulation of anammox-based process.

Intranasal administration of the essential oil from Perillae Folium ameliorates social defeat stress-induced behavioral impairments in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Perillae Folium, the leaves and twigs of Perilla frutescens (L.) Britton, has been included in many traditional Chinese medicine herbal formulas to treat depression. However, the precise antidepressant mechanism of the essential oil from Perillae Folium (PFEO) has not been fully investigated.

AIM OF THE STUDY

To assess the effects and potential mechanisms of PFEO on depression using animal models and network pharmacology analysis.

MATERIALS AND METHODS

PFEO was intranasally administered to a mouse model of social defeat stress (SDS). The antidepressant effects of PFEO on SDS-induced mice were evaluated using behavioral tests. Enzyme-linked immunosorbent assay (ELISA) and western blot were performed to measure the levels of depression-related biomarkers in the hippocampus and serum of the mice. The chemical compounds of PFEO were determined using gas chromatography-mass spectrometry (GC-MS). Network pharmacology and molecular docking analyses were conducted to investigate the potential bioactive components of PFEO and the mechanisms underlying the antidepressant effects. To validate the mechanisms of the bioactive compounds, in vitro models using PC12 and BV2 cells were established and the blood-brain barrier (BBB) permeability was evaluated.

RESULTS

The intranasal administration of PFEO suppressed SDS-induced depression in mice by increasing the time spent in the social zone and the social interactions in the social interaction test and by decreasing the immobility time in the tail suspension and forced swimming tests. Moreover, the PFEO treatment reduced the SDS-induced anxiety-like behavior, as inferred from the increased activity in the central zone observed in the open field test and in the open arms observed in the elevated plus maze test. PFEO administration recovered the SDS-induced decrease in the levels of 5-HT, NE, gamma-aminobutyric acid (GABA), and p-ERK in the hippocampus of mice. Furthermore, the increased serum corticosterone level was also attenuated by the PFEO treatment. A total of 21 volatile compounds were detected in PFEO using GC-MS, among which elemicin (15.52%), apiol (15.16%), and perillaldehyde (12.79%) were the most abundant ones. The PFEO compounds targeted 32 depression-associated genes, which were mainly related to neural cells and neurotransmission pathways. Molecular docking indicated good binding affinities between the bioactive components of PFEO (apiol, β-caryophyllene, elemicin, and myristicin) and the key targets, including ACHE, IL1B, IL6, MAOB, SLC6A2, SLC6A3, SLC6A4, and tumor necrosis factor. Among the four compounds, β-caryophyllene, elemicin, and myristicin were more effective in reducing neurotoxicity and neuroinflammation. Elemicin showed the highest BBB permeability rate.

CONCLUSIONS

This study shows the antidepressant activities of PFEO in an SDS-induced mouse model and suggests its potential mechanisms of action: regulation of the corticosterone levels, hippocampal neurotransmitters, and ERK signaling. Apiol, β-caryophyllene, elemicin, and myristicin may be the main contributors to the observed effects induced by PFEO. Further studies are needed to fully elucidate the underlying mechanisms and the main PFEO bioactive components.