The Aging GABAergic System and Its Nutritional Support

GABA (γ-aminobutyric acid) enrichment and detection methods in cereals: Unlocking sustainable health benefits

Gamma-aminobutyric acid (GABA), a non-protein amino acid primarily biosynthesized in cereals, is vital to the human neurological system. As the primary neurotransmitter, it promotes relaxation, inhibits depression and sleeplessness, and regulates synaptic transmission and neuronal development. GABA also protects the liver, kidneys, and intestines, reduces blood pressure, and fights cancer and inflammation. Colorimetric and enzyme-based procedures, biosensors, and High-Performance Liquid Chromatography primarily detect GABA. GABA content is enriched by treatments, like germination and fermentation, suitable and economical methods on industrial scales. Moreover, ultrasonication, abiotic stress, heat, and relative humidity are also utilized for GABA enrichment. With advancing technology and knowledge of the nutrients concerning human health, target-specific nutrition utilizing sustainable ingredients needs exploration. Conclusively, the current article delves into the latest developments in GABA enrichment and detection techniques and GABA's potential health benefits. Further studies are required to understand and refine enrichment procedures to develop GABA-enriched foods with health-promoting qualities.

Microbial gamma-aminobutyric acid synthesis: a promising approach for functional food and pharmaceutical applications

Gamma-aminobutyric acid (GABA) is a non-protein amino acid that is a main inhibitory neurotransmitter in the mammalian central nervous system. This mini-review emphasis on the microbial production of GABA and its potential benefits in various applications. Numerous microorganisms, including lactic acid bacteria, have been identified as efficient GABA producers. These microbes utilize glutamate decarboxylase enzymes to convert L-glutamate to GABA. Notable GABA-producing strains include Lactobacillus brevis, Lactobacillus plantarum, and certain Bifidobacterium species. Microbial GABA production offers numerous benefits over chemical synthesis, including cost-effectiveness, sustainability, and the potential for in situ production in fermented foods. Recent research has optimized fermentation conditions, genetic engineering approaches, and substrate utilization to enhance GABA yields. The benefits of GABA extend beyond its neurotransmitter role. Studies have shown its potential to reduce blood pressure, assuage anxiety, improve sleep quality, and improve cognitive function. These properties make microbial GABA production particularly attractive for developing functional foods, nutraceuticals, and pharmaceuticals. Future research directions include exploring novel GABA-producing strains, improving production efficiency, and investigating additional health benefits of microbially produced GABA.

Network Pharmacology Analysis of the Potential Pharmacological Mechanism of a Sleep Cocktail

Insomnia, also known as sleeplessness, is a sleep disorder due to which people have trouble sleeping, followed by daytime sleepiness, low energy, irritability, and a depressed mood. It may result in an increased risk of accidents of all kinds as well as problems focusing and learning. Dietary supplements have become popular products for alleviating insomnia, while the lenient requirements for pre-market research result in unintelligible mechanisms of different combinations of dietary supplements. In this study, we aim to systematically identify the molecular mechanisms of a sleep cocktail's pharmacological effects based on findings from network pharmacology and molecular docking. A total of 249 targets of the sleep cocktail for the treatment of insomnia were identified and enrichment analysis revealed multiple pathways involved in the nervous system and inflammation. Protein-protein interaction (PPI) network analysis and molecular complex detection (MCODE) analysis yielded 10 hub genes, including AKT1, ADORA1, BCL2, CREB1, IL6, JUN, RELA, STAT3, TNF, and TP53. Results from weighted correlation network analysis (WGCNA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of insomnia-related transcriptome data from peripheral blood mononuclear cells (PBMCs) showed that a sleep cocktail may also ease insomnia via regulating the inflammatory response. Molecular docking results reveal good affinity of Sleep Cocktail to 9 selected key targets. It is noteworthy that the crucial target HSP90AA1 binds to melatonin most stably, which was further validated by MD simulation.

Recent advances in the biosynthesis and industrial biotechnology of Gamma-amino butyric acid

GABA (Gamma-aminobutyric acid), a crucial neurotransmitter in the central nervous system, has gained significant attention in recent years due to its extensive benefits for human health. The review focused on recent advances in the biosynthesis and production of GABA. To begin with, the investigation evaluates GABA-producing strains and metabolic pathways, focusing on microbial sources such as Lactic Acid Bacteria, Escherichia coli, and Corynebacterium glutamicum. The metabolic pathways of GABA are elaborated upon, including the GABA shunt and critical enzymes involved in its synthesis. Next, strategies to enhance microbial GABA production are discussed, including optimization of fermentation factors, different fermentation methods such as co-culture strategy and two-step fermentation, and modification of the GABA metabolic pathway. The review also explores methods for determining glutamate (Glu) and GABA levels, emphasizing the importance of accurate quantification. Furthermore, a comprehensive market analysis and prospects are provided, highlighting current trends, potential applications, and challenges in the GABA industry. Overall, this review serves as a valuable resource for researchers and industrialists working on GABA advancements, focusing on its efficient synthesis processes and various applications, and providing novel ideas and approaches to improve GABA yield and quality.

γ-Aminobutyric acids (GABA) and serum GABA/AABA (G/A) ratio as potential biomarkers of physical performance and aging

Declining physical performance with age and disease is an important indicator of declining health. Biomarkers that identify declining physical performance would be useful in predicting treatment outcomes and identifying potential therapeutics. γ-aminobutyric acid (GABA), a muscle autocrine factor, is a potent inhibitor of muscle function and works as a muscle relaxant. L-α-aminobutyric acid (L-AABA) is a biomarker for malnutrition, liver damage, and depression. We sought to determine if GABA and L-AABA may be useful for predicting physical performance. Serum levels of GABA and L-AABA were quantified in 120 individuals divided by age, sex, and physical capacity into low, average, and high performer groups. Analyses explored correlations between serum levels and physical performance. Both GABA and the ratio of GABA/AABA (G/A), but not AABA, were highly positively associated with age (Pearson correlations r = 0.35, p = 0.0001 for GABA, r = 0.31, p = 0.0007 for G/A, n = 120). GABA showed negative associations in the whole cohort with physical performance [fast gait speed, 6 min walk test (6MWT), PROMIS score, and SF36PFS raw score] and with subtotal and femoral neck bone mineral density. L-AABA was positively associated with usual gait speed, 6MWT, total SPPB score, and SF36PFS raw score in the total cohort of 120 human subjects, also with 6MWT and SF36PFS raw score in the 60 male subjects, but no associations were observed in the 60 females. As both GABA and L-AABA appear to be indicative of physical performance, but in opposite directions, we examined the G/A ratio. Unlike GABA, the G/A ratio showed a more distinct association with mobility tests such as total SPPB score, usual and fast gait speed, 6MWT, and SF36PFS raw score in the males, regardless of age and metabolic status. Serum G/A ratio could be potentially linked to physical performance in the male population. Our findings strongly suggest that GABA, L-AABA, and the G/A ratio in human serum may be useful markers for both age and physical function. These new biomarkers may significantly enhance the goal of identifying universal biomarkers to accurately predict physical performance and the beneficial effects of exercise training for older adults.

Structure-function of DHEA binding proteins

Dehydroepiandrosterone (3β-hydroxy-5-androsten-17-one, DHEA) and its sulfated metabolite DHEA-S are the most abundant circulating steroids and are precursors for active sex steroid hormones, estradiol and testosterone. DHEA has a broad range of reported effects in the central nervous system (CNS), cardiovascular system, adipose tissue, kidney, liver, and in the reproductive system. The mechanisms by which DHEA and DHEA-S initiate their biological effects are diverse. DHEA and DHEA-S may directly bind to plasma membrane (PM) receptors, including a DHEA-specific, G-protein coupled receptor (GPCR) in endothelial cells; various neuroreceptors, e.g., aminobutyric-acid-type A (GABA(A)), N-methyl-d-aspartate (NMDA) and sigma-1 (S1R) receptors (NMDAR and SIG-1R). DHEA and DHEA-S directly bind the nuclear androgen and estrogen receptors (AR, ERα, or ERβ) although with significantly lower binding affinities compared to the steroid hormones, e.g., testosterone, dihydrotestosterone, and estradiol, which are the cognate ligands for AR and ERs. Thus, extra-gonadal metabolism of DHEA to the sex hormones must be considered for many of the biological benefits of DHEA. DHEA also actives GPER1 (G protein coupled estrogen receptor 1). DHEA activates constitutive androstane receptor CAR (CAR) and proliferator activated receptor (PPARα) by indirect dephosphorylation. DHEA affects voltage-gated sodium and calcium ion channels and DHEA-2 activates TRPM3 (Transient Receptor Potential Cation Channel Subfamily M Member 3). This chapter updates our previous 2018 review pertaining to the physiological, biochemical, and molecular mechanisms of DHEA and DHEA-S activity.

Potential diagnostic biomarkers for schizophrenia

Schizophrenia (SCH) is a complex and severe mental disorder with high prevalence, disability, mortality and carries a heavy disease burden, the lifetime prevalence of SCH is around 0.7%-1.0%, which has a profound impact on the individual and society. In the clinical practice of SCH, key problems such as subjective diagnosis, experiential treatment, and poor overall prognosis are still challenging. In recent years, some exciting discoveries have been made in the research on objective biomarkers of SCH, mainly focusing on genetic susceptibility genes, metabolic indicators, immune indices, brain imaging, electrophysiological characteristics. This review aims to summarize the biomarkers that may be used for the prediction and diagnosis of SCH.

Neuronal C/EBPβ/AEP pathway shortens life span via selective GABAnergic neuronal degeneration by FOXO repression

The age-related cognitive decline of normal aging is exacerbated in neurodegenerative diseases including Alzheimer's disease (AD). However, it remains unclear whether age-related cognitive regulators in AD pathologies contribute to life span. Here, we show that C/EBPβ, an Aβ and inflammatory cytokine-activated transcription factor that promotes AD pathologies via activating asparagine endopeptidase (AEP), mediates longevity in a gene dose-dependent manner in neuronal C/EBPβ transgenic mice. C/EBPβ selectively triggers inhibitory GABAnergic neuronal degeneration by repressing FOXOs and up-regulating AEP, leading to aberrant neural excitation and cognitive dysfunction. Overexpression of CEBP-2 or LGMN-1 (AEP) in Caenorhabditis elegans neurons but not muscle stimulates neural excitation and shortens life span. CEBP-2 or LGMN-1 reduces daf-2 mutant-elongated life span and diminishes daf-16-induced longevity. C/EBPβ and AEP are lower in humans with extended longevity and inversely correlated with REST/FOXO1. These findings demonstrate a conserved mechanism of aging that couples pathological cognitive decline to life span by the neuronal C/EBPβ/AEP pathway.