D-mannose alleviates intervertebral disc degeneration through glutamine metabolism.

BACKGROUND: Intervertebral disc degeneration (IVDD) is a multifaceted condition characterized by heterogeneity, wherein the balance between catabolism and anabolism in the extracellular matrix of nucleus pulposus (NP) cells plays a central role. Presently, the available treatments primarily focus on relieving symptoms associated with IVDD without offering an effective cure targeting its underlying pathophysiological processes. D-mannose (referred to as mannose) has demonstrated anti-catabolic properties in various diseases. Nevertheless, its therapeutic potential in IVDD has yet to be explored. METHODS: The study began with optimizing the mannose concentration for restoring NP cells. Transcriptomic analyses were employed to identify the mediators influenced by mannose, with the thioredoxin-interacting protein (Txnip) gene showing the most significant differences. Subsequently, small interfering RNA (siRNA) technology was used to demonstrate that Txnip is the key gene through which mannose exerts its effects. Techniques such as colocalization analysis, molecular docking, and overexpression assays further confirmed the direct regulatory relationship between mannose and TXNIP. To elucidate the mechanism of action of mannose, metabolomics techniques were employed to pinpoint glutamine as a core metabolite affected by mannose. Next, various methods, including integrated omics data and the Gene Expression Omnibus (GEO) database, were used to validate the one-way pathway through which TXNIP regulates glutamine. Finally, the therapeutic effect of mannose on IVDD was validated, elucidating the mechanistic role of TXNIP in glutamine metabolism in both intradiscal and orally treated rats. RESULTS: In both in vivo and in vitro experiments, it was discovered that mannose has potent efficacy in alleviating IVDD by inhibiting catabolism. From a mechanistic standpoint, it was shown that mannose exerts its anti-catabolic effects by directly targeting the transcription factor max-like protein X-interacting protein (MondoA), resulting in the upregulation of TXNIP. This upregulation, in turn, inhibits glutamine metabolism, ultimately accomplishing its anti-catabolic effects by suppressing the mitogen-activated protein kinase (MAPK) pathway. More importantly, in vivo experiments have further demonstrated that compared with intradiscal injections, oral administration of mannose at safe concentrations can achieve effective therapeutic outcomes. CONCLUSIONS: In summary, through integrated multiomics analysis, including both in vivo and in vitro experiments, this study demonstrated that mannose primarily exerts its anti-catabolic effects on IVDD through the TXNIP-glutamine axis. These findings provide strong evidence supporting the potential of the use of mannose in clinical applications for alleviating IVDD. Compared to existing clinically invasive or pain-relieving therapies for IVDD, the oral administration of mannose has characteristics that are more advantageous for clinical IVDD treatment.

Effects of Phenylacetylglutamine on the Susceptibility of Atrial Fibrillation in Overpressure-Induced HF Mice.

Phenylacetylglutamine (PAGln), a gut metabolite is substantially elevated in heart failure (HF). The increase of PAGln in plasma is associated with atrial fibrillation (AF), and contributes to AF pathogenesis. However, the role of PAGln in AF with HF remains uncertain. Therefore, this study aimed to determine the effect of PAGln on AF after HF. Thoracic aortic coarctation (TAC) created overpressure-induced HF mice for 4 weeks. Histopathology, biochemical, echocardiographic for assessment of cardiac function, and electrophysiological examination of several electrophysiological indexes (ERP, SNRT, and the occurrence rate of AF) were performed at the end of the HF mice model. We found that plasma PAGln levels were significantly elevated in PAGln-treated HF mice and that PAGln aggravated maladaptive structural remodeling and electrical remodeling, which aggravated the vulnerability of AF, shortened the ERP duration, prolonged the SNRT, increased the occurrence rate of AF in HF mice. Mechanistically, PAGln exacerbated ROS accumulation and increased the levels of phosphorylated PLB and CAMK II. Overall, PAGln played a vital role in promoting the occurrence of AF in HF mice by activating the CAMK II signaling pathway.

Effects of glutamine and omega-3 fatty acids on intestinal neomucosa formation on colon serosa in rats.

Background/aim: Intestinal neomucosa formation is a technique defined for the treatment of short bowel syndrome. This study evaluates the effect of glutamine and omega-3 fatty acids on the growth of intestinal neomucosa on the colonic serosal surface has been evaluated. Materials and methods: Thirty-two adult male Sprague-Dawley rats were randomly divided into 4 groups: sham, control, glutamine, and omega-3. Laparotomy was performed on all groups. For rats other than the sham group, a 1-cm full-thickness incision was made 4 cm proximal to the ileocecal valve, and colonic serosal surface was sutured as a serosal patch over these openings. By using the oral gavage technique, the glutamine group was ingested with 200 mg/kg/day of glutamine, and the omega-3 group was ingested with 100 mg/kg/day of omega-3 fatty acids. At the end of 14 days, the rats were euthanized, blood specimens were collected, and intestinal segments, including serosal patches, were excised. Results: Transforming growth factor-beta was significantly lower in the glutamine group compared to the control group. Similarly, fibroblast growth factor-2 was significantly lower in the glutamine group compared to the sham group. Intestinal neomucosa formation was observed in 100% of rats in the glutamine group. In the control and omega-3 groups, intestinal neomucosa formation was observed in 57.1% and 60% of rats, respectively. The inflammatory response, granulation tissue formation, and fibroblastic activity were more severe in the rats of the glutamine and omega-3 groups. Conclusion: The intestinal neomucosa formation is an experimental technique, and both glutamine and omega-3 fatty acids have the potential to positively affect inflammatory response, granulation tissue formation, and fibroblastic activity. Specifically, glutamine has a favorable effect on intestinal neomucosa formation.

[Exploration of mechanism of total triterpenoids from fruits of Chaenomeles speciosa against senescent GES-1 cells induced by D-galactose based on Gln/GLS1/α-KG metabolic axis and mitochondrial apoptosis signaling pathway].

Total triterpenoids from the fruits of Chaenomeles speciosa(TCS) are active components in the prevention and treatment of gastric mucosal damage, which have potential anti-aging effects. However, it is still unclear whether TCS can improve gastric aging, especially its molecular mechanism against gastric aging. On this basis, this study explored the effect and mechanism of TCS on senescent GES-1 cells induced by D-galactose(D-gal) to provide scientific data for the clinical use of TCS to prevent gastric aging. GES-1 cells cultured in vitro and those transfected with overexpression GLS1(GLS1-OE) plasmid of glutaminase 1(GLS1) were induced to aging by D-gal, and then TCS and or GLS1 inhibitor bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide(BPTES) were given. Cell survival rate, positive rate of ß-galactosidase(SA-ß-gal) staining, mitochondrial membrane potential(MMP), and apoptosis were investigated. GLS1 activity, levels of glutamine(Gln), glutamate(Glu), α-ketoglutarate(α-KG), urea, and ammonia in supernatant and cells were detected by enzyme-linked immunosorbent assay(ELISA) and colorimetric methods. The mRNA and protein expressions of GLS1 and the related genes of the mitochondrial apoptosis signaling pathway were measured by real-time fluorescence quantitative PCR and Western blot. The results manifested that compared with the D-gal model group and GLS1-OE D-gal model group, TCS significantly decreased the SA-ß-gal staining positive cell rate and MMP of D-gal-induced senescent GES-1 cells and GLS1-OE senescent GES-1 cells, inhibited the survival of senescent cells, and promoted their apoptosis(P<0.01). It decreased the activity of GLS1 and the content of Gln, Glu, α-KG, urea, and ammonia in supernatant and cell(P<0.01), reduced the concentration of cytochrome C(Cyto C) in mitochondria and the mRNA and protein expressions of GLS1 and proliferating nuclear antigen in cells(P<0.01). The mRNA expression of Bcl-2 and Bcl-xl, the protein expression of pro-caspase-9 and pro-caspase-3, and the ratio of Bcl-2/Bax and Bcl-xl/Bad in cells were decreased(P<0.01). Cyto C concentration in the cytoplasm, the mRNA expressions of Bax, Bad, apoptosis protease activating factor 1(Apaf-1), and protein expressions of cleaved-caspase-9, cleaved-caspase-3, cleaved-PARP-1 were increased(P<0.01). The aforementioned results indicate that TCS can counteract the senescent GES-1 cells induced by D-gal, and its mechanism may be closely related to suppressing the Gln/GLS1/α-KG metabolic axis, activating the mitochondrial apoptosis pathway, and thereby accelerating the apoptosis of the senescent cells and eliminating senescent cells.

L-Glutamine Substantially Improves 5-Fluorouracil-Induced Intestinal Mucositis by Modulating Gut Microbiota and Maintaining the Integrity of the Gut Barrier in Mice.

SCOPE: This study investigates the potential of glutamine to mitigate intestinal mucositis and dysbiosis caused by the chemotherapeutic agent 5-fluorouracil (5-FU). METHODS AND RESULTS: Over twelve days, Institute of Cancer Research (ICR) mice are given low (0.5 mg kg-1) or high (2 mg kg-1) doses of L-Glutamine daily, with 5-FU (50 mg kg-1) administered between days six and nine. Mice receiving only 5-FU exhibited weight loss, diarrhea, abnormal cell growth, and colonic inflammation, correlated with decreased mucin proteins, increased endotoxins, reduced fecal short-chain fatty acids, and altered gut microbiota. Glutamine supplementation counteracted these effects by inhibiting the Toll-like receptor 4/nuclear factor kappa B (TLR4/NF-κB) pathway, modulating nuclear factor erythroid 2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) oxidative stress proteins, and increasing mammalian target of rapamycin (mTOR) levels, thereby enhancing microbial diversity and protecting intestinal mucosa. CONCLUSIONS: These findings underscore glutamine's potential in preventing 5-FU-induced mucositis by modulating gut microbiota and inflammation pathways.

Glutamine supplementation improves the activity and immunosuppressive action of induced regulatory T cells in vitro and in vivo.

BACKGROUND: Glutamine is crucial for the activation and efficacy of T cells, and may play a role in regulating the immune environment. This study aimed to investigate the potential role of glutamine in the activation and proliferation of induced regulatory T cells (iTregs). METHODS: CD4+CD45RA+T cells were sorted from peripheral blood mononuclear cells and cultured to analyze iTreg differentiation. Glutamine was then added to the culture system to evaluate the effects of glutamine on iTregs by determining oxidative phosphorylation (OXPHOS), apoptosis, and cytokine secretion. Additionally, a humanized murine graft-versus-host disease (GVHD) model was constructed to confirm the efficacy of glutamine-treated iTregs in vivo. RESULTS: After being cultured in vitro, glutamine significantly enhanced the levels of Foxp3, CTLA-4, CD39, CD69, IL-10, TGF-ß, and Ki67 (CTLA-4, IL-10, TGF-ß are immunosuppressive markers of iTregs) compared with that of the control iTregs (P < 0.05). Furthermore, the growth curve showed that the proliferative ability of glutamine-treated iTregs was better than that of the control iTregs (P < 0.01). Compared with the control iTregs, glutamine supplementation significantly increased oxygen consumption rates and ATP production (P < 0.05), significantly downregulated Annexin V and Caspase 3, and upregulated BCL2 (P < 0.05). However, GPNA significantly reversed the effects of glutamine (P < 0.05). Finally, a xeno-GVHD mouse model was successfully established to confirm that glutamine-treated iTregs increased the mice survival rate, delayed weight loss, and alleviated colon injury. CONCLUSION: Glutamine supplementation can improve the activity and immunosuppressive action of iTregs, and the possible mechanisms by which this occurs are related to cell proliferation, apoptosis, and OXPHOS.

Glycolysis-non-canonical glutamine dual-metabolism regulation nanodrug enhanced the phototherapy effect for pancreatic ductal adenocarcinoma treatment.

Clinical pancreatic ductal adenocarcinoma (PDAC) treatment is severely limited by lack of effective KRAS suppression strategies. To address this dilemma, a reactive oxygen species (ROS)-responsive and PDAC-targeted nanodrug named Z/B-PLS was constructed to confront KRAS through dual-blockade of its downstream PI3K/AKT/mTOR and RAF/MEK/ERK for enhanced PDAC treatment. Specifically, photosensitizer zinc phthalocyanine (ZnPc) and PI3K/mTOR inhibitor BEZ235 (BEZ) were co-loaded into PLS which was constructed by click chemistry conjugating MEK inhibitor selumetinib (SEL) to low molecular weight heparin with ROS-responsive oxalate bond. The BEZ and SEL blocked PI3K/AKT/mTOR and RAF/MEK/ERK respectively to remodel glycolysis and non-canonical glutamine metabolism. ZnPc mediated photodynamic therapy (PDT) could enhance drug release through ROS generation, further facilitating KRAS downstream dual-blockade to create treatment-promoting drug delivery-therapeutic positive feedback. Benefiting from this broad metabolic modulation cascade, the metabolic symbiosis between normoxic and hypoxic tumor cells was also cut off simultaneously and effective tumor vascular normalization effects could be achieved. As a result, PDT was dramatically promoted through glycolysis-non-canonical glutamine dual-metabolism regulation, achieving complete elimination of tumors in vivo. Above all, this study achieved effective multidimensional metabolic modulation based on integrated smart nanodrug delivery, helping overcome the therapeutic challenges posed by KRAS mutations of PDAC.

Glutamine Promotes Porcine Intestinal Epithelial Cell Proliferation through the Wnt/ß-Catenin Pathway.

Glutamine (Gln) is a critical nutrient required by neonatal mammals for intestinal growth, especially for newborn piglets. However, the mechanisms underlying the role of Gln in porcine intestinal epithelium development are not fully understood. The objective of the current study was to explore the possible signaling pathway involved in the promotion of porcine intestinal epithelial cell (IPEC-J2) proliferation by Gln. The results showed that 1 mM Gln promoted IPEC-J2 cell proliferation, and tandem mass tag proteomics revealed 973 differentially expressed proteins in Gln-treated IPEC-J2 cells, 824 of which were upregulated and 149 of which were downregulated. Moreover, gene set enrichment analysis indicated that the Wnt signaling pathway is activated by Gln treatment. Western blotting analysis further confirmed that Gln activated the Wnt/ß-catenin signaling pathway. In addition, Gln increased not only cytosolic ß-catenin but also nuclear ß-catenin protein expression. LF3 (a ß-catenin/TCF4 interaction inhibitor) assay and ß-catenin knockdown demonstrated that Gln-mediated promotion of Wnt/ß-catenin signaling and cell proliferation were blocked. Furthermore, the inhibition of TCF4 expression suppressed Gln-induced cell proliferation. These findings further confirmed that Wnt/ß-catenin signaling is involved in the promotion of IPEC-J2 cell proliferation by Gln. Collectively, these findings demonstrated that Gln positively regulated IPEC-J2 cell proliferation through the Wnt/ß-catenin pathway. These data greatly enhance the current understanding of the mechanism by which Gln regulates intestinal development.

Suppressive effect of Yokukansan on glutamate released from canine keratinocytes.

Background: Canine atopic dermatitis (CAD) is caused by skin barrier dysfunction due to allergen exposure. Excessive glutamate release in the skin is associated with delayed skin barrier function recovery and epidermal thickening and lichenification. Treatment with Yokukansan (YKS), a traditional Japanese medicine, reduces dermatitis severity and scratching behavior in NC/Nga mice by decreasing epidermal glutamate levels. However, the association between canine keratinocytes and glutamate and the mechanism by which YKS inhibits glutamate release from keratinocytes remains unknown. Aim: We aimed to investigate glutamate release from canine progenitor epidermal keratinocytes (CPEKs) and the inhibitory effect of YKS on this release. We also explored the underlying mechanism of YKS to enable its application in CAD treatment. Methods: Glutamate produced from CPEKs in the medium at 24 hours was measured. The measurement conditions varied in terms of cell density and YKS concentration. CPEKs were treated with a glutamate receptor antagonist (MK-801), a glutamate transporter antagonist (THA), and a glutamate dehydrogenase inhibitor (epigallocatechin gallate; EGCG), and the inhibitory effect of YKS, YKS + THA, MK-801, and EGCG on this release was determined. MK-801 and glutamate dehydrogenase inhibitor were tested alone, and THA was tested in combination with YKS. Finally, glutamine incorporated into CPEKs at 24 hours was measured using radioisotope labeling. Results: CPEKs released glutamate in a cell density-dependent manner, inhibited by YKS in a concentration-dependent manner. Moreover, YKS reduced the intracellular uptake of radioisotope-labeled glutamine in a concentration-dependent manner. No involvement of glutamate receptor antagonism or activation of glutamate transporters was found, as suggested by previous studies. In addition, EGCG could inhibit glutamate release from CPEKs. Conclusion: Our findings indicated that glutamate release from CPEKs could be effectively inhibited by YKS, suggesting the utility of YKS in maintaining skin barrier function during CAD. In addition, CPEKs are appropriate for analyzing the mechanism of YKS. However, we found that the mechanism of action of YKS differs from that reported in previous studies, suggesting that it may have had a similar effect to EGCG in this study. Further research is warranted to understand the exact mechanism and clinical efficacy in treating CAD.

Effectiveness of glutamine and arginine in wound healing of pressure ulcers: A systematic review protocol.

INTRODUCTION: Various nutrients play a physiological role in the healing process of pressure ulcers (PUs). Nutritional interventions include the administration of enteral nutritional supplements and formulas containing arginine, glutamine, and micronutrients. The aim of this systematic review is to evaluate the effectiveness of enteral nutritional supplements and formulas containing arginine and glutamine on wound-related outcomes. These include (1) time to healing, (2) changes in wound size, (3) local wound infection, (4) PU recurrence, and (5) PU-related pain. MATERIALS AND METHODS: This protocol was developed according to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P). A search will be conducted in the Cochrane Library, EMBASE, PubMed (MEDLINE), CINAHL (EBSCOhost interface) and Web of Science. In addition, a manual search will be conducted to identify relevant records. Except for systematic reviews, no restrictions will be placed on the study design, the population studied or the setting. Studies that do not address PUs, in vitro studies and studies that do not report wound-related outcomes will be excluded. Study selection, risk of bias assessment and data extraction will be performed independently by three researchers. Depending on the extent of heterogeneity of interventions, follow-up time and populations, results will be summarised either by meta-analysis or narrative synthesis. CONCLUSIONS: This is the first systematic review to identify, evaluate and summarise the current evidence for enteral arginine and glutamine supplementation on wound-related outcomes in PUs. The review will provide a solid basis for deriving valid and clinically relevant conclusions in this area.

Inhibition of glutamine metabolism increases sensitivity to plasma-activated medium-induced cytotoxicity.

Non-thermal atmospheric pressure plasma (NTP), an ionized gas containing electrons, ions, radicals, and photons, has various biological effects, including wound healing and anticancer effects. Plasma-activated medium (PAM), which is prepared by irradiating medium with NTP, preferentially kills cancer cells. Large amounts of reactive oxygen species (ROS) and reactive nitrogen species (RNS) included in PAM are closely related to its anticancer effects. The precise mechanism of PAM-induced cytotoxicity is not fully understood; however, PAM exposure has been reported to reduce cellular energy metabolism. Glutamine (Gln) is an important amino acid as an energy source in cancer cells. Gln is converted to glutamate by glutaminase (GLS), and is utilized to synthesize ATP and glutathione (GSH). Expression levels of GLS have been shown to be higher in certain types of cancers. In this study, we examined the effects of GLS inhibition on PAM cytotoxicity using breast cancer MDA-MB-231 cells. Pretreatment with BPTES, a glutaminase 1 (GLS1) inhibitor, dose-dependently enhanced PAM-induced cell death. PAM-induced ROS production and γ-H2AX formation, a DNA damage marker, were increased in cells pretreated with BPTES compared with PAM alone. BPTES pretreatment enhanced a PAM-induced decrease in intracellular GSH, indicating the possibility that BPTES reduces the antioxidant capacity of MDA-MB-231 cells. In addition, BPTES pretreatment enhanced PAM-induced loss of the mitochondrial membrane potential and reduction of ATP production. Moreover, GLS1 knockdown promoted PAM-induced cell death. Taken together, the combination of GLS1 inhibitors such as BPTES is considered to be useful for enhancing the cytotoxic effects of PAM against cancer cells.

KRAS Mutation Detection with (2S,4R)-4-[18F]FGln for Noninvasive PDAC Diagnosis.

Pancreatic ductal adenocarcinoma (PDAC), which has a poor prognosis and nonspecific symptoms and progresses rapidly, is the most common pancreatic cancer type. Inhibitors targeting KRAS G12D and G12C mutations have been pivotal in PDAC treatment. Cancer cells with different KRAS mutations exhibit various degrees of glutamine dependency; in particular, cells with KRAS G12D mutations exhibit increased glutamine uptake. (2S,4R)-4-[18F]FGln has recently been developed for clinical cancer diagnosis and tumor cell metabolism analysis. Thus, we verified the heterogeneity of glutamine dependency in PDAC models with different KRAS mutations by a visual and noninvasive method with (2S,4R)-4-[18F]FGln. Two tumor-bearing mouse models (bearing the KRAS G12D or G12C mutation) were injected with (2S,4R)-4-[18F]FGln, and positron emission tomography (PET) imaging features and biodistribution were observed and analyzed. The SUVmax in the regions of interest (ROI) was significantly higher in PANC-1 (G12D) tumors than in MIA PaCa-2 (G12C) tumors. Biodistribution analysis revealed higher tumor accumulation of (2S,4R)-4-[18F]FGln and other metrics, such as T/M and T/B, in the PANC-1 mouse models compared to those in the MIAPaCa-2 mouse models. In conclusion, PDAC cells with the KRAS G12D and G12C mutations exhibit various degrees of (2S,4R)-4-[18F]FGln uptake, indicating that (2S,4R)-4-[18F]FGln might be applied to detect KRAS G12C and G12D mutations and provide treatment guidance.

A redox-responsive prodrug for tumor-targeted glutamine restriction.

Modulating the metabolism of cancer cells, immune cells, or both is a promising strategy to potentiate cancer immunotherapy in the nutrient-competitive tumor microenvironment. Glutamine has emerged as an ideal target as cancer cells highly rely on glutamine for replenishing the tricarboxylic acid cycle in the process of aerobic glycolysis. However, non-specific glutamine restriction may induce adverse effects in unconcerned tissues and therefore glutamine inhibitors have achieved limited success in the clinic so far. Here we report the synthesis and evaluation of a redox-responsive prodrug of 6-Diazo-5-oxo-L-norleucine (redox-DON) for tumor-targeted glutamine inhibition. When applied to treat mice bearing subcutaneous CT26 mouse colon carcinoma, redox-DON exhibited equivalent antitumor efficacy but a greatly improved safety profile, particularly, in spleen and gastrointestinal tract, as compared to the state-of-the-art DON prodrug, JHU083. Furthermore, redox-DON synergized with checkpoint blockade antibodies leading to durable cures in tumor-bearing mice. Our results suggest that redox-DON is a safe and effective therapeutic for tumor-targeted glutamine inhibition showing promise for enhanced metabolic modulatory immunotherapy. The approach of reversible chemical modification may be generalized to other metabolic modulatory drugs that suffer from overt toxicity.

Effects of Dietary Glutamine Supplementation on the Modulation of Microbiota and Th17/Treg Immune Response Signaling Pathway in Piglets after Lipopolysaccharide Challenge.

BACKGROUND: Glutamine (Gln) has an important effect on the growth performance and immune function of piglets. However, the effect of Gln on intestinal immunity in piglets through modulating the signaling pathways of the helper T cells 17 (Th17)/regulatory T cells (Treg) immune response has not been reported. OBJECTIVE: This study aimed to determine the effect of Gln on piglet growth performance and immune stress response and its mechanism in piglets. METHODS: Twenty-four weaned piglets were randomly assigned to 4 treatments with 6 replicates each, using a 2 × 2 factorial arrangement: diet (basal diet or 1% Gln diet) and immunological challenge [saline or lipopolysaccharide (LPS)]. After 21 d, half of the piglets on the basal diet and 1% Gln diet received the intraperitoneal injection of LPS and the other half received the same volume of normal saline. RESULTS: The results showed that Gln increased average daily feed intake and average daily weight gain in comparison with the control group (P < 0.05). Dietary Gln increased the villus height, villus height-to-crypt depth ratio, and the abundance of Bacteroidetes, Lactobacillus sp., and Ruminococcus sp. while reducing the abundance of Firmicutes, Clostridium sensu stricto 1 sp., and Terrisporobacter sp. (P < 0.05). Furthermore, Gln increased the concentration of short-chain fatty acids in the colon and the expression of genes of interleukin (IL)-10, transforming growth factor-beta-1, forkhead box P3 while downregulating the expression of genes of IL-6, IL-8, IL-1ß, tumor necrosis factor-α, IL-17A, IL-21, signal transducer and activator of transcription 3, and rar-related orphan receptor c in ileum (P < 0.05). Correlation analysis demonstrated a strong association between colonic microbiota, short-chain fatty acids, and ileal inflammatory cytokines. CONCLUSIONS: These results suggest that dietary Gln could improve growth performance and attenuate LPS-challenged intestinal inflammation by modulating microbiota and the Th17/Treg immune response signaling pathway in piglets.

Glutamine sustains energy metabolism and alleviates liver injury in burn sepsis by promoting the assembly of mitochondrial HSP60-HSP10 complex via SIRT4 dependent protein deacetylation.

Burns and burn sepsis, characterized by persistent and profound hypercatabolism, cause energy metabolism dysfunction that worsens organ injury and systemic disorders. Glutamine (Gln) is a key nutrient that remarkably replenishes energy metabolism in burn and sepsis patients, but its exact roles beyond substrate supply is unclear. In this study, we demonstrated that Gln alleviated liver injury by sustaining energy supply and restoring redox balance. Meanwhile, Gln also rescued the dysfunctional mitochondrial electron transport chain (ETC) complexes, improved ATP production, reduced oxidative stress, and protected hepatocytes from burn sepsis injury. Mechanistically, we revealed that Gln could activate SIRT4 by upregulating its protein synthesis and increasing the level of Nicotinamide adenine dinucleotide (NAD+), a co-enzyme that sustains the activity of SIRT4. This, in turn, reduced the acetylation of shock protein (HSP) 60 to facilitate the assembly of the HSP60-HSP10 complex, which maintains the activity of ETC complex II and III and thus sustain ATP generation and reduce reactive oxygen species release. Overall, our study uncovers a previously unknown pharmacological mechanism involving the regulation of HSP60-HSP10 assembly by which Gln recovers mitochondrial complex activity, sustains cellular energy metabolism and exerts a hepato-protective role in burn sepsis.

Long-term cadmium exposure induces epithelial-mesenchymal transition in breast cancer cells by activating CYP1B1-mediated glutamine metabolic reprogramming in BT474 cells and MMTV-Erbb2 mice.

Cadmium (Cd) exposure is known to enhance breast cancer (BC) progression. Cd promotes epithelial-mesenchymal transition (EMT) in BC cells, facilitating BC cell aggressiveness and invasion, but the underlying molecular mechanisms are unclear. Hence, transgenic MMTV-Erbb2 mice (6 weeks) were orally administered Cd (3.6 mg/L, approximately equal to 19.64 µΜ) for 23 weeks, and BC cells (BT474 cells) were exposed to Cd (0, 0.1, 1 or 10 µΜ) for 72 h to investigate the effect of Cd exposure on EMT in BC cells. Chronic Cd exposure dramatically expedited tumor metastasis to multiple organs; decreased E-cadherin density; and increased Vimentin, N-cadherin, ZEB1, and Twist density in the tumor tissues of MMTV-Erbb2 mice. Notably, transcriptomic analysis of BC tumors revealed cytochrome P450 1B1 (CYP1B1) as a key factor that regulates EMT progression in Cd-treated MMTV-Erbb2 mice. Moreover, Cd increased CYP1B1 expression in MMTV-Erbb2 mouse BC tumors and in BT474 cells, and CYP1B1 inhibition decreased Cd-induced BC cell malignancy and EMT in BT474 cells. Importantly, the promotion of EMT by CYP1B1 in Cd-treated BC cells was presumably controlled by glutamine metabolism. This study offers novel perspectives into the effect of environmental Cd exposure on driving BC progression and metastasis, and this study provides important guidance for comprehensively assessing the ecological and health risks of Cd.

Effectiveness of Glutamine Oral Care in Reducing Oral Mucositis and Improving Oral Health After Neurosurgery: A Randomized Controlled Trial with Microbiome Analysis.

BACKGROUND Hospital-acquired infections negatively impact the health of inpatients and are highly costly to treat. Oral care reduces the microorganism number in the mouth and lungs and is essential in preventing postoperative oral inflammation, lung infection, and other complications. This study was designed to determine the effects of oral care with glutamine on oral health, oral flora, and incidence of pneumonia in patients after neurosurgery. MATERIAL AND METHODS This was a parallel, double-blind, randomized trial. Patients admitted to the Neurosurgery Department of the hospital from July to October 2021 were selected. Three hundred patients who met the inclusion criteria were randomized into 3 groups. The control group (n=100) received oral care with routine oral nursing methods with saline, whereas the experimental group (n=100) received oral care with 5% glutamine. A compound chlorhexidine group (n=100) was set as a positive control. All patients, care providers, and investigators were blinded to the group assignment. The incidence of local debris, oral mucositis, halitosis, dryness, oral mucositis disorders, and oral flora types were collected and analyzed in all groups. RESULTS The incidence of local debris, oral mucositis, halitosis, dryness, and other oral mucositis disorders in the glutamine oral care group was significantly decreased, compared with that of the control group. Oral flora types in the glutamine and chlorhexidine groups were significantly reduced. CONCLUSIONS Oral care with 5% glutamine after neurosurgery is associated with a lower incidence of oral disorders and pneumonia, and a significant reduction in oral flora.

Effect of dietary l-glutamine supplementation on the intestinal physiology and growth during Solea senegalensis larval development.

The maturation of the intestinal digestive and absorptive functions might limit the amount of absorbed nutrients to fulfil the high requirements of the fast-growing marine fish larva. Glutamine (Gln) has been described to improve intestinal epithelium functions, due to its involvement in energy metabolism and protein synthesis. The purpose of this study was to evaluate dietary 0.2% Gln supplementation on aspects of intestinal physiology, protein metabolism and growth-related genes expression in Senegalese sole larvae. Experiment was carried out between 12 and 33 days post hatching (DPH) and fish were divided into two experimental groups, one fed Artemia spp. (CTRL) and the other fed Artemia spp. supplemented with Gln (GLN). GLN diet had two times more Gln than the CTRL diet. Samples were collected at 15, 19, 26 and 33 DPH for biometry, histology, and digestive enzymes activity, and at 33 DPH for gene expression, protein metabolism and AA content determination. Growth was significantly higher for Senegalese sole fed GLN diet, supported by differences on protein metabolism and growth-related gene expression. Slight differences were observed between treatments regarding the intestinal physiology. Overall, GLN diet seems to be directed to enhance protein metabolism leading to higher larval growth.

Oral post-treatment supplementation with a combination of glutamine, citrulline, and antioxidant vitamins additively mitigates jejunal damage, oxidative stress, and inflammation in rats with intestinal ischemia and reperfusion.

INTRODUCTION: Intestinal ischemia and reperfusion (IIR) injury is closely associated with oxidative stress. Evidence shows that oral supplementation with glutamine and citrulline alleviates IIR-induced jejunal damage. We investigated the effects of a combination of glutamine, citrulline, and antioxidant vitamins on IIR-induced jejunal damage, oxidative stress, and inflammation. METHOD: Male Wistar rats that underwent 60 min of superior mesenteric artery occlusion were orally administered glutamine plus citrulline (GC), vitamin C plus E (CE), or a combination of GC and CE 15 min before and 3, 9, and 21 h after reperfusion. Healthy rats without IIR were used as controls. RESULTS: After reperfusion for 24 h, rats with IIR showed lower levels of red blood cells, hemoglobin, serum glucose, and jejunal DNA and increased white blood cell counts compared to controls (1-way ANOVA with the least significant difference, P < 0.05). The IIR-induced decrease in serum albumin and increase in plasma interleukin-6 and jejunal thiobarbituric acid-reactive substances (TBARS) were significantly reversed by GC and/or CE. The results of the 2-way ANOVA indicated that GC was the main factor that increased jejunal villus height and muscularis DNA, and CE was the main factor that increased jejunal muscularis protein and decreased jejunal proinflammatory cytokine levels and myeloperoxidase activity. In addition, GC and CE are the main factors that decrease plasma proinflammatory cytokine levels and the jejunal apoptotic index. CONCLUSION: Oral post-treatment supplementation with glutamine and citrulline, combined with vitamins C and E, may alleviate IIR-induced oxidative stress, inflammation, and jejunal damage.

In-Ovo Glutamine Administration Enhances Intestinal Development and Functions in Broiler Chickens: Insights from Enteroid Models.

BACKGROUND: Early life events play significant roles in tissue development and animal health in their later life. Early nutrition, through in-ovo delivery, has shown beneficial effects on improving intestinal health in broiler chickens. However, the underlying mechanism is not fully investigated. A recently developed enteroid culture technique allows investigations on intestinal epithelial functions that are close to physiologic conditions. OBJECTIVES: In this study, we evaluated the short- and long-term effects of in-ovo administration of glutamine (Gln) on intestinal epithelial development and functions by using intestinal enteroid culture and tissue electrophysiologic analysis. METHODS: A hundred eggs of commercial Cobb500 broilers were in-ovo injected with 0.2 mL of either phosphate-buffered saline (PBS) or 3% Gln at embryonic day 18 (E18). Chicks were killed on the day of hatch, and at 3- and 14-d posthatch. Enteroids were generated from the small intestine. After 4 d of culture, enteroids were harvested for 5-ethynyl-2'-deoxyuridine proliferation, fluorescein isothiocyanate-4 kDa dextran permeability, and glucose absorption assays. At day 3 (d3) and day 14 (d14), intestinal barrier and nutrient transport functions were measured by the Ussing chamber. The gene expression of epithelial cell markers, nutrient transporters, and tight-junction proteins were analyzed in both intestinal tissues and enteroids. RESULTS: In comparison with the PBS control group, in-ovo Gln increased intestinal villus morphology, epithelial cell proliferation, and differentiation, and altered epithelial cell population toward increased number of enteroendocrine and goblet cells while decreasing Paneth cells. Enteroids gene expression of nutrient transporters (B0AT1, SGLT1, and EAAT3), tight junction (ZO2), glucose absorption, and barrier functions were enhanced on the day of hatch. Long-term increases of intestinal di-peptide and alanine transport were observed at day 14 posthatch. CONCLUSIONS: Together our results suggested that the in-ovo injection of Gln stimulated intestinal epithelium proliferation and programmed the epithelial cell differentiation toward absorptive cells.