Protective effects of L-theanine and dihydromyricetin on reproductive function in male mice under heat stress.

Heat stress can impair the male reproductive function. L-Theanine and dihydromyricetin have biological activities against heat stress; however, their effects on reproductive function in heat-stressed males are unclear. In this study, male mice were given L-theanine, dihydromyricetin, or a combination of both for 28 days, followed by 2 h of heat stress daily for 7 days. All interventions alleviated heat stress-induced testicular damage, improving the testicular organ index, sperm density, acrosome integrity, sperm deformity rate, and hormone levels. Treatment increased the antioxidant enzyme activity and decreased the markers of oxidative and inflammatory stress in the testes. A combination dose of 200 + 200 mg kg-1 d-1 showed the best protective effect. The potential mechanism involves the regulation of HSP27 and HSP70, which regulate the levels of reproductive hormones through the StAR/Cyp11a1/Hsd3b1/Cyp17a1/Hsd17b3 pathway, alleviate inflammation and oxidative stress through the P38/NF-κB/Nrf2/HO-1 pathway, and regulate the Bcl-2/Fas/Caspase3 apoptotic pathway. Overall, L-theanine and dihydromyricetin may play a protective role against heat stress-induced reproductive dysfunction, suggesting their potential use in heat stress-resistant foods.

Hepatoprotective effects and mechanisms of l-theanine and epigallocatechin gallate combined intervention in alcoholic fatty liver rats.

BACKGROUND: Chronic excessive alcohol consumption can lead to alcoholic fatty liver, posing substantial health risks. l-Theanine (LTA) and epigallocatechin gallate (EGCG) in tea exert antioxidant and hepatoprotective effects. However, the combined effects of LTA and EGCG on rats with alcoholic fatty liver, and the underlying mechanisms of such effects, remain unclear. In this study, Sprague Dawley (SD) rats were fed with alcohol for 6 weeks to induce alcoholic fatty liver. Subsequently, for another 6 weeks, the rats were administered LTA (200 mg kg-1 day-1), EGCG (200 mg kg-1 day-1), or a combination of LTA with EGCG (40 mg kg-1 day-1 l-Thea +160 mg kg-1 day-1 EGCG), respectively. RESULTS: The combined use of LTA and EGCG for alcoholic fatty liver disease had more significant effects than their individual administration. This combination reduced the activity of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) as well as the levels of hepatic triglyceride (TG), malondialdehyde (MDA), and reactive oxygen species (ROS) in the rats. The combined intervention also increased hepatic superoxide dismutase (SOD) and glutathione peroxidase activity. Reductions in hepatic fat accumulation and inflammatory responses were observed. The mechanism underlying these effects primarily involved the inhibition of fatty acid synthesis and the alleviation of lipid peroxidation through the downregulation of the mRNA and protein expression of TNF-α, SREBP1c, and CYP2E1 and the upregulation of the mRNA and protein expression of ADH1, ALDH2, Lipin-1, PPARαPPARα, AMPK, and PGC-1α, thereby promoting the oxidative decomposition of fatty acids and reducing the synthesis of cholesterol and glucose. CONCLUSION: l-Theanine and EGCG appear to be able to alleviate alcoholic fatty liver by modulating lipid metabolism and ameliorating oxidative stress, indicating their potential as natural active ingredients in anti-alcoholic fatty liver food products. © 2024 Society of Chemical Industry.

Extracellular vesicles containing MFGE8 from colorectal cancer facilitate macrophage efferocytosis.

BACKGROUND: Colorectal cancer (CRC) commonly exhibits tolerance to cisplatin treatment, but the underlying mechanisms remain unclear. Within the tumor microenvironment, macrophages play a role in resisting the cytotoxic effects of chemotherapy by engaging in efferocytosis to clear apoptotic cells induced by chemotherapeutic agents. The involvement of extracellular vesicles (EVs), an intercellular communicator within the tumor microenvironment, in regulating the efferocytosis for the promotion of drug resistance has not been thoroughly investigated. METHODS: We constructed GFP fluorescent-expressing CRC cell lines (including GFP-CT26 and GFP-MC38) to detect macrophage efferocytosis through flow cytometric analysis. We isolated and purified CRC-secreted EVs using a multi-step ultracentrifugation method and identified them through electron microscopy and nanoflow cytometry. Proteomic analysis was conducted to identify the protein molecules carried by CRC-EVs. MFGE8 knockout CRC cell lines were constructed using CRISPR-Cas9, and their effects were validated through in vitro and in vivo experiments using Western blotting, immunofluorescence, and flow cytometric analysis, confirming that these EVs activate the macrophage αvß3-Src-FAK-STAT3 signaling pathway, thereby promoting efferocytosis. RESULTS: In this study, we found that CRC-derived EVs (CRC-EVs) enhanced macrophage efferocytosis of cisplatin-induced apoptotic CRC cells. Analysis of The Cancer Genome Atlas (TCGA) database revealed a high expression of the efferocytosis-associated gene MFGE8 in CRC patients, suggesting a poorer prognosis. Additionally, mass spectrometry-based proteomic analysis identified a high abundance of MFGE8 protein in CRC-EVs. Utilizing CRISPR-Cas9 gene edition system, we generated MFGE8-knockout CRC cells, demonstrating that their EVs fail to upregulate macrophage efferocytosis in vitro and in vivo. Furthermore, we demonstrated that MFGE8 in CRC-EVs stimulated macrophage efferocytosis by increasing the expression of αvß3 on the cell surface, thereby activating the intracellular Src-FAK-STAT3 signaling pathway. CONCLUSIONS: Therefore, this study highlighted a mechanism in CRC-EVs carrying MFGE8 activated the macrophage efferocytosis. This activation promoted the clearance of cisplatin-induced apoptotic CRC cells, contributing to CRC resistance against cisplatin. These findings provide novel insights into the potential synergistic application of chemotherapy drugs, EVs inhibitors, and efferocytosis antagonists for CRC treatment.

Potential Hepatoprotective Effects of Allicin on Carbon Tetrachloride-Induced Acute Liver Injury in Mice by Inhibiting Oxidative Stress, Inflammation, and Apoptosis.

The global burden of liver disease is enormous, which highlights the need for effective hepatoprotective agents. It was reported that allicin exhibits protective effects against a range of diseases. In this study, we further evaluated allicin's effect and mechanism in acute hepatic injury. Liver injury in mice was induced by intraperitoneal injection with 1% CCl4 (10 mL/kg/day). When the first dose was given, CCl4 was given immediately after administration of different doses of allicin (40, 20, and 10 mg/kg/day) as well as compound glycyrrhizin (CGI, 80 mg/kg/day), and then different doses of allicin (40, 20, and 10 mg/kg/day) as well as compound glycyrrhizin (CGI, 80 mg/kg/day) were administrated every 12 h. The animals were dissected 24 h after the first administration. The findings demonstrated a significant inhibition of CCl4-induced acute liver injury following allicin treatment. This inhibition was evidenced by notable reductions in serum levels of transaminases, specifically aspartate transaminase, along with mitigated histological damage to the liver. In this protective process, allicin plays the role of reducing the amounts or the expression levels of proinflammatory cytokines, IL-1ß, IL-6. Furthermore, allicin recovered the activities of the antioxidant enzyme catalase (CAT) and reduced the production of malondialdehyde (MDA) in a dose-dependent manner, and also reduced liver Caspase 3, Caspase 8, and BAX to inhibit liver cell apoptosis. Further analysis showed that the administration of allicin inhibited the increased protein levels of Nuclear factor-erythroid 2-related factor 2 (Nrf2) and NAD(P)H:quinone oxidoreductase 1 (NQO1), which is related to inflammation and oxidative stress. The in vitro study of the LPS-induced RAW264.7 inflammatory cell model confirmed that allicin can inhibit important inflammation-related factors and alleviate inflammation. This research firstly clarified that allicin has a significant protective effect on CCl4-induced liver injury via inhibiting the inflammatory response and hepatocyte apoptosis, alleviating oxidative stress associated with the progress of liver damage, highlighting the potential of allicin as a hepatoprotective agent.

Bioinformatic Identification and Expression Analyses of the MAPK-MAP4K Gene Family Reveal a Putative Functional MAP4K10-MAP3K7/8-MAP2K1/11-MAPK3/6 Cascade in Wheat (Triticum aestivum L.).

The mitogen-activated protein kinase (MAPK) cascades act as crucial signaling modules that regulate plant growth and development, response to biotic/abiotic stresses, and plant immunity. MAP3Ks can be activated through MAP4K phosphorylation in non-plant systems, but this has not been reported in plants to date. Here, we identified a total of 234 putative TaMAPK family members in wheat (Triticum aestivum L.). They included 48 MAPKs, 17 MAP2Ks, 144 MAP3Ks, and 25 MAP4Ks. We conducted systematic analyses of the evolution, domain conservation, interaction networks, and expression profiles of these TaMAPK-TaMAP4K (representing TaMAPK, TaMAP2K, TaMAP3K, and TaMAP4K) kinase family members. The 234 TaMAPK-TaMAP4Ks are distributed on 21 chromosomes and one unknown linkage group (Un). Notably, 25 of these TaMAP4K family members possessed the conserved motifs of MAP4K genes, including glycine-rich motif, invariant lysine (K) motif, HRD motif, DFG motif, and signature motif. TaMAPK3 and 6, and TaMAP4K10/24 were shown to be strongly expressed not only throughout the growth and development stages but also in response to drought or heat stress. The bioinformatics analyses and qRT-PCR results suggested that wheat may activate the MAP4K10-MEKK7-MAP2K11-MAPK6 pathway to increase drought resistance in wheat, and the MAP4K10-MAP3K8-MAP2K1/11-MAPK3 pathway may be involved in plant growth. In general, our work identified members of the MAPK-MAP4K cascade in wheat and profiled their potential roles during their response to abiotic stresses and plant growth based on their expression pattern. The characterized cascades might be good candidates for future crop improvement and molecular breeding.

Layer-by-layer assembled decomposable nanocapsules for light-responsive release of pesticide imidacloprid on Aphis craccivora Koch.

BACKGROUND: Conventional pesticide formulations are often inefficient because of low biological uptake after spraying. Controlled release nanopesticides can release pesticides precisely in response to specific stimuli, thereby killing pests and pathogens using the least effective concentration. This study aims to develop nanocapsule-based photo-decomposable nanopesticides for efficient pesticide control. RESULTS: The target nanopesticides were successfully fabricated using layer-by-layer assembly of the negative azobenzene-grafted hyaluronic acid (azo-HA) and positive polydimethyldiallylammonium chloride (polyDADMAC), confirmed by UV-visible, dynamic light scattering, Zeta potential and transmission electron microscopy measurements. The particle size and Zeta potential of the fabricated nanocapsules were 220 nm and +46.1 mV, respectively, and the nanocapsules were found to remain stable for up to 30 days. The optimized drug loading and encapsulation ratio of imidacloprid (IMI) in IMI/azo-HA@polyDADMAC were 21.5% and 91.3%, respectively. Cumulative release of IMI from the nanopesticides increased from ~50% to ~95% upon UV light irradiation (365 nm). The half lethal concentration (LC50) value of the nanopesticides toward Aphis craccivora Koch decreased from 2.22 to 0.55 mg L-1 upon UV light irradiation. CONCLUSION: The trans to cis transformation of the azo group in HA decomposed IMI/azo-HA@polyDADMAC nanopesticides upon UV irradiation, thus facilitating the release of IMI, resulting in a decrease in the concentration of pesticides required for efficient pesticide control. Our work demonstrated the great potential of light-responsive nanocapsules as a controlled release nanocarrier for efficient and eco-friendly pesticide control in sustainable agriculture. © 2024 Society of Chemical Industry.

The protective effect of L-theanine on the intestinal barrier in heat-stressed organisms.

Heat stress caused by heatwaves, extreme temperatures, and other weather can damage the intestinal barrier of organisms. L-Theanine (LTA) attenuates heat stress-induced oxidative stress, inflammatory responses, and impaired immune function, but its protective effect on the intestinal barrier of heat-stressed organisms is unclear. In this study, low (100 mg kg-1 d-1), medium (200 mg kg-1 d-1), and high (400 mg kg-1 d-1) dosages of LTA were used in the gavage of C57BL/6J male mice that were experimented on for 50 d. These mice were subjected to heat stress for 2 h d-1 at 40 ± 1 °C and 60 ± 5% RH in the last 7 d. LTA attenuated the heat stress-induced decreases in body mass and feed intake, and the destruction of intestinal villi and crypt depth; reduced the serum levels of FITC-dextran and D-LA, as well as the DAO activity; and upregulated the colonic tissues of Occludin, Claudin-1, and ZO-1 mRNA and occludin protein expression. The number of goblet cells in the colon tissue of heat-stressed organisms increased in the presence of LTA, and the expression levels of Muc2, Muc4 mRNA, and Muc2 protein were upregulated. LTA increased the abundance of Bifidobacterium and Turicibacter, and decreased the abundance of Enterorhabdus and Desulfovibrio in the intestinal tract of heat-stressed organisms and restored gut microbiota homeostasis. LTA promoted the secretion of IL-4, IL-10, and sIgA and inhibited the secretion of TNF-α and IFN-γ in the colon of heat-stressed organisms. The expressions of Hsf1, Hsp70, Hsph1, TLR4, P38 MAPK, p-P65 NF-κB, MLCK mRNA, and proteins were downregulated by LTA in the colon of heat-stressed organisms. These results suggest that LTA protects the intestinal barrier in heat-stressed organisms by modulating multiple molecular pathways. Therefore, this study provides evidence on how tea-containing LTA treatments could be used to prevent and relieve intestinal problems related to heat stress.

Regulatory Effects and Mechanisms of L-Theanine on Neurotransmitters via Liver-Brain Axis Under a High Protein Diet.

Excessive protein intake causes liver and brain damage and neurotransmitter disorders, thereby inducing cognitive dysfunction. L-theanine can regulate the neurotransmitter content and show great potential in liver and brain protection. However, it remains unclear whether l-theanine effectively regulates neurotransmitter content under high-protein diet. A 40-day feeding experiment was performed in Sprague Dawley rats to investigate the regulatory effects and mechanisms of l-theanine on neurotransmitters via liver-brain axis in high-protein diets. The results showed that a 30% protein diet increased the liver and brain neurotransmitter content while maintaining the normal structure of liver and the hippocampal CA1 of brain and improving the autonomous behavior of rats. In contrast, 40% and 50% protein diets decreased the content of neurotransmitters, affected autonomous behavior, destroyed the hippocampal CA1 of brain structure, increased hepatic inflammatory infiltration, lipid degeneration, and hepatocyte eosinophilic change in liver, increased liver AST, ALT, MDA, CRP, and blood ammonia level, and decreased liver SOD and CAT level. However, l-theanine improved liver and brain neurotransmitter content, autonomous behavior, liver and hippocampal brain structure, and liver biochemical indicators in 40% and 50% protein diets. To explore how LTA can eliminate the adverse effects of a high-protein diet, we analyzed different metabolites and proteomes and using western blotting for validate quantitatively. We found that l-theanine regulates the activity of PF4 and G protein subunit alpha i2, increases the content of brain-derived neurotrophic factor and dopamine under a 20% protein diet. In addition, l-theanine can activate the adenylate cyclase-protein kinase A pathway through the protein alpha/beta-hydrolase domain protein 12 to regulate the content of neurotransmitters under a 40% protein diet, thereby exerting a neuroprotective effect.

l-Theanine delays d-galactose-induced senescence by regulating the cell cycle and inhibiting apoptosis in rat intestinal cells.

BACKGROUND: Intestinal senescence is associated with several aging-related diseases. l-Theanine (LTA) has demonstrated strong potential as an antioxidant and antisenescence agent. This study investigated the regulatory effect of LTA on cellular senescence using an in vitro model of d-galactose (D-Gal)-induced senescence in the rat epithelial cell line, intestinal epithelioid cell-6 (IEC-6). RESULTS: Treatment of IEC-6 cells with 40 mg/mL D-Gal for 48 h resulted in the successful development of the senescent cell model. Compared with D-Gal alone, both LTA preventive and delayed intervention increased cell viability and the ratio of JC-1 monomers to aggregates, increased the antioxidant capacity, and decreased the advanced glycation end product (AGE) levels and the overall number of senescent cells. Preventive and delayed intervention with 1000 µM LTA alleviated the D-Gal-induced cell cycle arrest by regulating p38, p53, CDK4, and CDK6 expression at the mRNA and protein levels, and further induced CycD1 proteins. Moreover, LTA preventive intervention reduced apoptosis to a greater degree than delayed intervention by upregulating the expression of the receptors of AGEs, Bax, Bcl-2, and NF-κB at the mRNA and protein levels. CONCLUSION: Our findings indicate that LTA intervention could attenuate senescence in IEC-6 cells by regulating the cell cycle and inhibiting apoptosis. © 2023 Society of Chemical Industry.

L-Theanine alleviates heat stress through modulation of gut microbiota and immunity.

BACKGROUND: Heat stress (HS) damages the intestines, disrupting gut microbiota and immune balance. l-Theanine (LTA), found in tea, alleviates oxidative stress and cell apoptosis under HS; however, its effects on gut microbiota and immunity under HS remain unclear. To investigate this, we administered LTA doses of 100, 200, and 400 mg·kg-1 ·d-1 to C57BL/6J mice. On day 44, the model group and LTA intervention group were subjected to continuous 7-day HS treatment for 2 h per day. RESULTS: The results demonstrated that LTA intervention improved food intake, body weight, and intestinal epithelium, and reduced the water intake of heat-stressed mice. It increased the abundance of Turicibacter, Faecalibaculum, Bifidobacterium, and norank_f_Muribaculaceae, while reducing that of Lachnoclostridium and Desulfovibrio. LTA intervention also increased the concentrations of amino acid and lipid metabolites, regulated macrophage differentiation stimulated by gut microbiota and metabolites, reduced the antigen presentation by macrophages to the specific immune system, promoted B-cell differentiation and sIgA secretion, inhibited pro-inflammatory factors, and enhanced intestinal defense. Mechanistically, LTA downregulated heat shock protein 70 expression and the TLR4/NF-κB/p38 MAPK signaling pathway, restoring gut microbiota and immune balance. CONCLUSION: We suggest that LTA can alleviate HS by modulating gut microbiota, metabolites, and immunity, indicating its potential as a natural active ingredient for anti-HS food products. © 2023 Society of Chemical Industry.

Efficacy of mesenchymal stromal cells in the treatment of unexplained recurrent spontaneous abortion in mice: An analytical and systematic review of meta-analyses.

OBJECTIVES: Unexplained recurrent spontaneous abortion (URSA) remains an intractable reproductive dilemma due to the lack of understanding of the pathogenesis. This study aimed to evaluate the preclinical evidence for the mesenchymal stromal cell (MSC) treatment for URSA. METHODS: A meticulous literature search was independently performed by two authors across the Cochrane Library, EMBASE, and PubMed databases from inception to April 9, 2023. Each study incorporated was assessed using the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) risk of bias tool. The amalgamated standardized mean difference (SMD) accompanied by 95% confidence interval (CI) were deduced through a fixed-effects or random-effects model analysis. RESULTS: A total of ten studies incorporating 140 mice were subjected to data analysis. The MSC treatment yielded a significant reduction in the abortion rate within the URSA model (OR = 0.23, 95%CI [0.17, 0.3], P<0.00001). Moreover, it elicited a positive modulatory impact on the expression profiles of several inflammatory cytokines in the decidual tissue of URSA murine models, inclusive of IL4 (SMD 1.63, 95% CI [0.39, 2.86], P = 0.01), IL10 (SMD 1.60, 95% CI [0.58, 2.61], P = 0.002), IFN-γ (SMD -1.66, 95%CI [-2.79, -0.52], P = 0.004), and TNF-α (SMD -1.98, 95% CI [-2.93, -1.04], P< 0.0001). Subgroup analyses underscored that the administration mode of intraperitoneal and uterine horn injections, and sources of bone MSCs and adipose-derived MSCs contributed positively to the expression of IL4, IL10, and decreased the expression of IFN-γ in decidual tissue of URSA (P<0.05). Conversely, the tail vein injections subgroup was observed with no statistical significance (P>0.05). CONCLUSIONS: The findings underscore the considerable potential of MSCs in URSA therapy. Nonetheless, the demand for enhanced transparency in research design and direct comparisons between various MSC sources and administration routes in URSA is paramount to engendering robust evidence that could pave the way for successful clinical translation.

L-theanine regulates the immune function of SD rats fed high-protein diets through the FABP5/IL-6/STAT3/PPARα pathway.

The protein levels in a diet are correlated with immunity but the long-term intake of excessive protein can compromise various aspects of health. L-theanine regulates immunity and protein metabolism; however, how its regulatory immunity effects under a high-protein diet are unclear. We used proteomics, metabonomics, and western blotting to analyze the effects of diets with different protein levels on immune function in rats to determine the role of L-theanine in immunity under a high-protein diet. The long-term intake of high-protein diets (≥40% protein) promoted oxidative imbalance and inflammation. These were alleviated by L-theanine. High-protein diets inhibited peroxisome proliferator-activated receptor (PPAR)α expression through the interleukin (IL)-6/signal transducer and activator of transcription (STAT)3 pathway and mediated inflammation. L-theanine downregulated anti-fatty acid-binding protein 5 (FABP5), inhibited the IL-6/STAT3 axis, and reduced high-protein diet-induced PPARα inhibition. Therefore, L-theanine alleviates the adverse effects of high-protein diets via the FABP5/IL-6/STAT3/PPARα pathway and regulates the immunity of normally fed rats through the epoxide hydrolase (EPHX)2/nuclear factor-kappa B inhibitor (IκB)α/triggering receptor expressed on myeloid cells (TREM)1 axis.

L-Theanine attenuates heat stress-induced proteotoxicity and alterations in carbohydrate and lipid metabolism via heat shock factor 1.

Extreme heat caused by global warming accelerated the frequency of heat stress (HS). Proteotoxic stress induced by the aggregation of misfolded proteins and metabolic stress triggered by alterations in the metabolism were observed during HS. The activation of heat shock factor 1 (Hsf1) and its interaction with adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) are critical in addressing proteotoxicity and metabolic stress in heat-stressed organisms. Previous studies have shown that L-theanine (LTA) can regulate nutrient metabolism through the AMPK pathway and can alleviate HS. Therefore, we hypothesize that LTA may help in restoring homeostasis by regulating nutrient metabolism under HS. Here, we investigated the effects of LTA on nutrient metabolism in heat-stressed rats and characterized the underlying mechanisms using RNA sequencing and metabonomics. The results showed that LTA alleviated HS-induced liver damage, promoted body weight gain, decreased serum cortisol and enhanced the total protein content. Besides, it regulated the expression of genes related to carbohydrate, lipid and amino acid metabolism and altered metabolite levels. Moreover, LTA inhibited the expression of Hsf1 and heat shock protein 70 (Hsp70), promoted AMPK phosphorylation and the expression of glucose-6-phosphatase catalytic subunit 1 (G6pc), and inhibited the phosphorylation of acetyl-CoA carboxylase 1 (ACC1) in heat-stressed rats. Mechanistically, LTA alleviated HS-induced proteotoxic stress by acting on Hsf1/Hsp70; simultaneously, it promoted AMPK phosphorylation by suppressing Hsf1 expression, which in turn inhibited fatty acid synthesis and hepatic gluconeogenesis, thus alleviating HS-induced metabolic stress. These results suggest that LTA regulates nutrient metabolism through Hsf1/AMPK and alleviates HS-induced proteotoxicity via Hsf1/Hsp70.

Colorectal cancer-derived extracellular vesicles containing HSP70 enhance macrophage phagocytosis by up-regulating MARCO expression.

In recent years, we have realized that extracellular vesicles (EVs) play a critical role in regulating the intercellular communication between tumor and immune cells in the tumor microenvironment (TME). Tumor-derived extracellular vesicles (TDEVs) profoundly affect the functional changes of tumor-associated macrophages (TAMs) and promote their M2 polarization. Meanwhile, macrophages have a strong phagocytic ability in phagocytosing apoptotic cells. Especially in the course of chemotherapy or radiotherapy, TAMs can phagocytose and remove apoptotic tumor cells, showing anti-inflammatory and pro-tumor effects. However, the underlying mechanisms by which TDEVs regulate macrophage phagocytosis of apoptotic tumor cells have not been fully elucidated. In this study, we focused on the effect of colorectal cancer-derived extracellular vesicles (CRC-EVs) on macrophages. We demonstrated that CRC-EVs enhanced macrophage phagocytosis of apoptotic CRC cells. We then determined that heat shock protein 70 (HSP70) carried in CRC-EVs was responsible for this effect by using mass spectrometry-based proteomic analysis and the CRISPR-Cas9 system. Through transcriptome sequencing of macrophages, we found that the enhanced phagocytosis of macrophages was mainly due to the up-regulation of the macrophage receptor with collagenous structure (MARCO). In addition, we confirmed that the up-regulation of MARCO was mediated by the AKT-STAT3 signaling pathway. Taken together, this study revealed a novel EVs-mediated macrophage phagocytosis mechanism involved in the clearance of apoptotic tumor cells in the TME. Targeting TDEVs may have potential therapeutic applications in tumor treatment.

Synergistic effects of L-theanine and epigallocatechin gallate in alleviating ovalbumin allergy by regulating intestinal immunity through inhibition of mast cell degranulation.

Ovalbumin (OVA), a commonly consumed food protein, can cause severe allergies and intestinal immune disorders. L-Theanine (LTA) and epigallocatechin gallate (EGCG) regulate intestinal immunity. However, it is unclear whether an LTA and EGCG combined intervention can alleviate OVA allergy (OVA-A) by modulating intestinal-specific immunity, and it is unknown whether there is a synergistic effect between LTA and EGCG. Therefore, we treated BALB/c OVA-sensitized mice with LTA, EGCG, or a combination of both (LTA + EGCG) to investigate the effects of LTA and EGCG on intestinal-specific immunity regulation and underlying mechanisms. Female mice were intraperitoneally injected with OVA to establish OVA-sensitive mouse models. MLEO LTA + EGCG (20 mg kg-1 d-1 LTA + 80 mg kg-1 d-1 EGCG) and HLEO (30 mg kg-1 d-1 LTA + 120 mg kg-1 d-1 EGCG) exerted more beneficial effects on alleviating OVA-A (weight gain, allergy score, jejunum structure, mast cell [MC] degranulation, thymus and spleen indices) than LTA or EGCG alone (p < 0.01). Based on the alleviation of OVA-A by LTA + EGCG, we selected MLEO mice for 16S rDNA, flow cytometry, and western blot analyses. The 16S rDNA results showed that MLEO increased the abundance of Lactobacillaceae, Lachnospiraceae, and Ruminococcaceae, and decreased that of Helicobacteraceae (p < 0.01). The flow cytometry and western blotting results indicated that MLEO reduced the number of dendritic cells available to capture OVA, thereby lowering the Th2 immune response and decreasing the IL-4 and IL-13 levels. Meanwhile, the attenuation of the Th2 immune response inhibits the cross-linking of OVA and FcεRI, thus reducing MC degranulation and decreasing the serum HIS and mMCPT-1 levels through the FcεRI/Btk/PLCγ signaling pathway. LTA + EGCG also inhibits the Th2 immune response through the FcεRI/Lyn/Syk/PI3K/AKT signaling pathway and decreases the serum IL-4 and IL-13 levels. Notably, LTA + EGCG promotes the Treg and Th1 immune responses and inhibits the Th17 immune response, altering the levels of the corresponding cytokines. Therefore, LTA + EGCG can synergistically alleviate OVA-A by regulating intestinal immunity through MC degranulation inhibition.

L-Theanine alleviates heat stress-induced impairment of immune function by regulating the p38 MAPK signalling pathway in mice.

With the current trend of global warming, heat stress-induced impairment could seriously endanger human health. L-Theanine is a non-protein amino acid in tea with various biological activities, including immunoregulatory, anti-anxiety, and anti-oxidation. However, its effect on immune function under heat stress and the underlying mechanism are currently unclear. In this study, male BALB/c mice were used as experimental objects to explore the effect of L-theanine on heat stress-induced changes in immune function and its mechanism. Three doses of L-theanine were used: low (100 mg kg-1 d-1), medium (200 mg kg-1 d-1), and high (400 mg kg-1 d-1). Treatment with L-theanine could attenuate the heat stress-induced reductions in body weight and feed intake in mice, alleviate damage in the liver and jejunum, and inhibit the inflammatory factors IL-6, IL-1ß, and TNF-α. Aspartate aminotransferase and alanine transaminase activity levels and the malondialdehyde content decreased, while the IgA, IgM, and IgG contents increased in response to L-theanine. It is possible that L-theanine affects the P38 signalling pathway and inhibits the increase in p-P65/P65 caused by the overexpression of HSP27 and regulation of PPAR-γ and Foxp3 proteins, thereby alleviating immune dysfunction caused by heat stress.

L-Theanine Mitigates the Harmful Effects of Excess High-Protein Diet in Rats by Regulating Protein Metabolism.

SCOPE: l-Theanine (LTA) is a non-protein amino acid that contributes to the flavor of tea and can regulate protein metabolism of healthy organisms. However, it is unknown whether it regulates protein metabolism in individuals on high-protein diets (HPDs). METHODS AND RESULTS: Here, Sprague-Dawley rats are fed HPDs with different protein supply ratios and administered a diverse dose of LTA for 40 days. Results show that HPDs with an energy supply ratio from protein >40% impair the liver and kidneys, elevate serum ammonia and urea nitrogen, induce amino acid (AA) catabolism, and promote fatty acid (FA) synthesis via FA-binding protein 5 (Fabp5) and acetyl-CoA carboxylase 1 (ACC1). LTA intervention alleviates HPD-induced hepatic and renal injury and improves serum biochemical indices. It increases hepatic free AA content and inhibits FA synthesis by downregulating Fabp5 and ACC1. It promotes protein synthesis by acting on the mammalian target of rapamycin (mTOR) pathway, thereby alleviating HPD-induced metabolic disorders. CONCLUSIONS: This study demonstrates that LTA mitigates kidney and liver damage induced by long-term excess HPDs by regulating protein metabolism.

L-Theanine regulates lipid metabolism by modulating gut microbiota and bile acid metabolism.

BACKGROUND: l-Theanine (LTA) is a biologically active ingredient in tea that shows great potential for regulating lipid metabolism. Bile acids (BA), an important end-product of cholesterol catabolism, participate in the regulation of lipid metabolism and gut microbiota. Here, we investigated the effect of LTA on lipid metabolism and the mechanism by which it regulates BA metabolism and gut microbiota. Male BALB/c mice were treated with LTA for 28 days. RESULTS: Daily LTA doses of 100 and 300 mg kg-1  d-1 altered the gut microbiota in mice, predominantly by decreasing Lactobacillus, Streptococcus, Bacteroides, Clostridium and Enterorhabdus microbes associated with bile-salt hydrolase (BSH) activity, thereby decreasing the activity of BSH and increasing the levels of ileum conjugated BA (such as glycocholic acid (GCA) and lithocholic acid), thereby inhibiting the intestinal farnesoid X receptor (FXR)-fibroblast growth factor 15 (FGF15) signaling pathway. Inhibition of FXR-FGF15 signaling was accompanied by upregulation of cholesterol 7α-hydroxylase (CYP7A1) mRNA and protein expression and increased hepatic production of cholic acid, deoxycholic acid, GCA, glycine cholic acid and glycine ursodeoxycholic acid. Meanwhile, increasing hepatic unconjugated BA upregulated the mRNA and protein expression of liver 3-hydroxy-3-methylglutaryl-CoA reductase and downregulated the mRNA and protein expression of stearoyl-CoA desaturase-1, liver low-density lipoprotein receptor and type B scavenger receptor. Therefore, the serum levels of cholesterol and triglycerides decreased. CONCLUSION: Our findings indicate that LTA regulates lipid metabolism by modulating the gut microbiota and BA metabolism via the FXR-FGF15-CYP7A1 pathway. © 2022 Society of Chemical Industry.

L-Theanine Modulates Intestine-Specific Immunity by Regulating the Differentiation of CD4+ T Cells in Ovalbumin-Sensitized Mice.

Ovalbumin (OVA), a common food protein, can cause deadly allergies with intestine-specific immune reactions. L-Theanine (LTA) shows great potential for regulating intestinal immunity. To investigate the regulatory effect of LTA intervention on intestine-specific immunity, a 41 day experiment was performed on BALB/c OVA-sensitized mice. The results show that injecting female mice intraperitoneally with 50 µg of OVA and administering 30 mg of OVA 4 times can successfully establish an OVA-sensitized mouse model. LTA intervention significantly increased weight gain and thymus index (p < 0.05), decreased allergy and diarrhea scores (p < 0.05), and improved jejunum structure. Meanwhile, the histological score and degranulation of mast cells decreased. LTA intervention increased Clostridiales, Lachnospiraceae, Lactobacillus, Prevotella, and Ruminococcus abundance while decreasing Helicobacter abundance. Flow cytometry and Western blotting results indicated that 200 and 400 mg/kg of LTA upregulated the expression of T-bet and Foxp3 proteins (p < 0.05), thus promoting the differentiation of jejunum CD4+ T cells to Th1 and Tregs and increasing the cytokines IFN-γ, IL-10, and TGF-ß (p < 0.05). We found that 200 and 400 mg/kg of LTA downregulated the expression of RORγt and GATA3, thus inhibiting the differentiation of Th2 and Th17 cells and decreasing cytokines IL-4, IL-5, IL-13 TNF-α, IL-6, and IL-17A (p < 0.05). LTA inhibited the degranulation of mast cells and significantly decreased the serum levels of OVA-IgE, HIS, and mouse MCPT-1 (p < 0.05). Therefore, LTA intervention alleviated OVA allergy by improving intestine-specific immunity.