Synergistic neuroprotective and cognitive-enhancing effects of Walnut Peptide and Theanine in human brain organoid and mouse stress models

Stress is a prevalent mental health concern emerging predominantly in late adolescence or early adulthood. Since 2007, the Food and Drug Administration (FDA) has not approved any novel anxiolytic pharmaceuticals, fueling interest in nutritional supplements as alternative therapies for stress management. Building on prior zebrafish research, this study investigates the synergistic effects of Theanine (Th) and Walnut Peptide (WP) on stress mitigation and cognitive enhancement. Utilizing the human brain organoid stress (BO-stress) model, WP+ Th were observed to reduce stress and regulate expression of neurotransmitters, including Gamma-Aminobutyric Acid (GABA), serotonin (5-HT), dopamine (DA), and acetylcholine (Ach), as well as brain-derived neurotrophic factor (BDNF) and serotonin transporter (SERT). Subsequent in vivo study using C57BL/6J mouse-stress model demonstrated that the treatment (Th 85 mg/mL + WP 200 mg/mL), or administrated with vehicles, significantly improved their performance in stress and cognitive assessments, partially normalized neurotransmitter imbalances by modulating SERT and BDNF expression. These findings highlighted the potential of using WP + Th, particularly when delivered with vehicles (eg: powder/yogurt/milk), as a novel combined therapeutic approach for stress management and cognitive enhancement. We performed a correlation analysis between BO-stress model and mouse-stress model, revealing a alignement in the SERT levels.In addition, SERT was highly correlated with other markers in the mouse hippocampus and may represent a key target for modulating the balance between stress and cognition. Significance StatementThis study established an innovative human brain organoid-stress model and, in conjunction with mouse-stress model, elucidated the synergistic actions of Theanine and Walnut Peptide in mitigating stress and augmenting cognitive function. Their beneficial effects were mediated through the regulation of SERT and BDNF, presenting a promising non-pharmacological avenue for mental health care. In addition, species differences between humans and mice were also examined through correlation analysis of brain organoids and mouse models. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/640260v1_ufig1.gif" ALT="Figure 1"> View larger version (69K): org.highwire.dtl.DTLVardef@1a81886org.highwire.dtl.DTLVardef@e2281dorg.highwire.dtl.DTLVardef@1b7b167org.highwire.dtl.DTLVardef@dff9aa_HPS_FORMAT_FIGEXP M_FIG C_FIG