mTOR Research Articles

PI3K/AKT signaling and neuroprotection in ischemic stroke: molecular mechanisms and therapeutic perspectives.

It has been reported that the PI3K/AKT signaling pathway plays a key role In the pathogenesis of ischemic stroke. As a result, the development of drugs targeting the PI3K/AKT signaling pathway has attracted increasing attention from researchers. This article reviews the pathological mechanisms and advancements in research related to the signaling pathways in ischemic stroke, with a focus on the PI3K/AKT signaling pathway.The key findings include the following: (1) The complex pathological mechanisms of ischemic stroke can be categorized into five major types: excitatory amino acid toxicity, Ca2+ overload, inflammatory response, oxidative stress, and apoptosis. (2) The PI3K/AKT-mediated signaling pathway is closely associated with the occurrence and progression of ischemic stroke, which primarily involves the NF-kB, NRF2, BCL-2, mTOR, and endothelial NOS signaling pathways. (3) Natural products, including flavonoids, quinones, alkaloids, phenylpropanoids, phenols, terpenoids, and iridoids, show great potential as candidate substances for the development of innovative anti-stroke medications. (4) Recently, novel therapeutic techniques, such as electroacupuncture and mesenchymal stem cell therapy, have demonstrated the potential to improve stroke outcomes by activating the PI3K/AKT signaling pathway, providing new possibilities for the treatment and rehabilitation of patients with ischemic stroke. Future investigations should focus on the direct regulatory mechanisms of drugs targeting the PI3K/AKT signaling pathway and their clinical translation to develop innovative treatment strategies for ischemic stroke.

METTL3 affects the biological function of lung adenocarcinoma through the FGF2/PI3K/AKT /mTOR pathway.

This study aims to investigate the role of the m6A regulatory factor METTL3 in LUAD. By examining the expression of METTL3 in LUAD and conducting cellular functional experiments, the biological functions of METTL3 were discussed. mRNA-seq and MeRIP-qPCR were used to identify downstream target genes and pathways. The expression level of METTL3 in LUAD is lower than that in the control group. The downregulation of METTL3 promoted the proliferation, migration, and invasion of LUAD cells, while overexpression of METTL3 results in the opposite effects. Furthermore, we found that FGF2 was negatively regulated by METTL3. Inhibiting FGF2 reversed the tumor-promoting effects caused by METTL3 downregulation in LUAD cells. Silencing METTL3 enhanced the stability of FGF2 mRNA. Silencing FGF2 resulted in reduced activity of the PI3K/AKT/mTOR signaling pathway in METTL3 knockdown LUAD cells. In summary, our findings unveil an intricate signaling network involving METTL3/FGF2/PI3K/AKT/mTOR in LUAD and provide valuable insights into the molecular mechanisms underlying tumor progression, thus holding significant implications for targeted therapy and advancing LUAD research.

Somatostatin interneuron fate-mapping and structure in a Pten knockout model of epilepsy.

Disruption of inhibitory interneurons is common in the epileptic brain and is hypothesized to play a pivotal role in epileptogenesis. Abrupt disruption and loss of interneurons is well-characterized in status epilepticus models of epilepsy, however, status epilepticus is a relatively rare cause of epilepsy in humans. How interneuron disruption evolves in other forms of epilepsy is less clear. Here, we explored how somatostatin (SST) interneuron disruption evolves in quadruple transgenic Gli1-CreERT2, Ptenfl/fl, SST-FlpO, and frt-eGFP mice. In these animals, epilepsy develops following deletion of the mammalian target of rapamycin (mTOR) negative regulator phosphatase and tensin homolog (Pten) from a subset of dentate granule cells, while downstream Pten-expressing SST neurons are fate-mapped with green fluorescent protein (GFP). The model captures the genetic complexity of human mTORopathies, in which mutations can be restricted to excitatory neuron lineages, implying that interneuron involvement is later developing and secondary. In dentate granule cell (DGC)-Pten knockouts (KOs), the density of fate-mapped SST neurons was reduced in the hippocampus, but their molecular phenotype was unchanged, with similar percentages of GFP+ cells immunoreactive for SST and parvalbumin (PV). Surviving SST neurons in the dentate gyrus had larger somas, and the density of GFP+ processes in the dentate molecular layer was unchanged despite SST cell loss and expansion of the molecular layer, implying compensatory sprouting of surviving cells. The density of Znt3-immunolabeled puncta, a marker of granule cell presynaptic terminals, apposed to GFP+ processes in the hilus was increased, suggesting enhanced granule cell input to SST neurons. Finally, the percentage of GFP+ cells that were FosB positive was significantly increased, implying that surviving SST neurons are more active. Together, findings suggest that somatostatin-expressing interneurons exhibit a combination of pathological (cell loss) and adaptive (growth) responses to hyperexcitability and seizures driven by upstream Pten KO excitatory granule cells.

Photosensitizing metal–organic framework nanoparticles combined with tumor-sensitization strategies can enhance the phototherapeutic effect upon medullary thyroid carcinoma

Photodynamic therapy (PDT) utilizing metal-organic frameworks (MOFs) has developed as a new and efficacious treatment for malignant tumors located on the surface of the human body. In order to achieve more effective PDT treatment outcomes, the traditional method has been to increase the intensity of the laser irradiation, but this approach can easily lead to tissue burns. In this study, we developed a new type of nanoparticle, F68-PKI@PCN224, aims to achieve effective PDT upon medullary thyroid carcinoma (MTC) which is an uncommon form of thyroid cancer that originates in the parafollicular cells of the thyroid and the therapeutic outlook for patients with MTC remains unsatisfactory. F68-PKI@PCN224 combines the antitumor features of PDT with mammalian target of rapamycin (mTOR) inhibitor PKI-587 (PKI). The tumor sensitization, slow release, and pH response features of F68-PKI@PCN224 was demonstrated by a series of in vitro and in vivo experiments / assays. F68-PKI@PCN224 achieved the long-term activation and slow releasing of PKI and TCPP in MTC tumor tissues. During the process of generating PDT effects, F68-PKI@PCN224 enhanced the tumor's sensitivity to PDT, direct laser irradiation of MTC cells or subcutaneous tumor tissues. As a result, low-dose phototherapy achieves a higher anti-tumor effect upon F68-PKI@PCN224 compared with TCPP. This study reveals the synergistic effect between tumor sensitization by mTOR inhibitor and PDT and initially unveils the mechanism of action of these nanoparticles.

An emerging role of ferulic acid on sub-adult grass carp (Ctenopharyngodon idellus): Increasing protein digestion and regulating amino acid and oligopeptide transporters expression

This study was conducted to evaluate the effect of supplement ferulic acid on growth performance, digestive ability and transport function of amino acids and oligopeptides in the intestine of sub-adult grass carp (Ctenopharyngodon idellus). The experiment was divided into two parts: a. Digestion experiment: healthy grass carp (678.83±1.00 g) were divided into two groups: control group (0 mg/kg FA) and ferulic acid group (100 mg/kg FA) for 2 weeks; b. Growth experiment: healthy grass carp (678.83±1.00 g) were divided into five treatment groups, the control group (FA0) with no ferulic acid and the experimental group supplemented with ferulic acid 50 (FA50), 100 (FA100), 150 (FA150) and 200 (FA200) mg/kg feed for 9 weeks. The results showed that a. Ferulic acid supplementation increased the apparent digestibility of crude protein and crude fat in grass carp. b. Ferulic acid supplementation improved the growth performance and feed efficiency (FE) of grass carp; increased the activities of trypsin and Na+/K+-ATPase; and up-regulated the levels of mRNAs of some neutral and cationic (non-anionic) amino acid transporter proteins (Solute Carrier Family7member1 (SLC7A7), SLC7A8, etc.) and H+/oligopeptide transporter protein 1 (PepT1) gene and protein levels. In addition, ferulic acid promoted the gene expression levels of protein kinase B (Akt), target of rapamycin (TOR); up-regulated the mRNA levels of tail-side-associated homologous frame transcription factor 2 (Cdx2), cAMP response element-binding protein (CREB), and transcriptional co-activator-specific protein 1 (Sp1), and down-regulated the gene and protein levels of protein kinase CβII (PKCβII). In a word, dietary ferulic acid promoted growth performance, digestion, as well as amino acid and oligopeptide transport capacities. Finally, based on regression analyses of percentage weight gain (PWG), FE, specific growth rate (SGR), intestine fold height, trypsin activity, and Na+/K+-ATPase activity, we recommend optimal supplementation levels of ferulic acid in sub-adult grass carp of 92.18–120.60 mg/kg diet.

Enhancement of Autophagy in Macrophages via the p120-Catenin-Mediated mTOR Signaling Pathway.

Autophagy serves as a critical regulator of immune responses in sepsis. Macrophages are vital constituents of both innate and adaptive immunity. In this study, we delved into the intricate role of p120-catenin (p120) in orchestrating autophagy in macrophages in response to endotoxin stimulation. Depletion of p120 effectively suppressed LPS-induced autophagy in both J774A.1 macrophages and murine bone marrow-derived macrophages. LPS not only elevated the interaction between p120 and L chain 3 (LC3) I/II but also facilitated the association of p120 with mammalian target of rapamycin (mTOR). p120 depletion in macrophages by small interfering RNA reduced LPS-induced dissociation of mTOR and Unc-51-like kinase 1 (ULK1), leading to an increase in the phosphorylation of ULK1. p120 depletion also enhanced LPS-triggered macrophage apoptosis, as evidenced by increased levels of cleaved caspase 3, 7-aminoactinomycin D staining, and TUNEL assay. Notably, inhibiting autophagy reversed the decrease in apoptosis caused by LPS stimulation in macrophages overexpressing p120. Additionally, the ablation of p120 inhibited autophagy and accentuated apoptosis in alveolar macrophages in LPS-challenged mice. Collectively, our findings strongly suggest that p120 plays a pivotal role in fostering autophagy while concurrently hindering apoptosis in macrophages, achieved through modulation of the mTOR/ULK1 signaling pathway in sepsis. This underscores the potential of targeting macrophage p120 as an innovative therapeutic avenue for treating inflammatory disorders.

Combined spatially resolved metabolomics and spatial transcriptomics reveal the mechanism of RACK1-mediated fatty acid synthesis.

Lipid metabolism is altered in rapidly proliferating cancer cells, where fatty acids (FAs) are utilized in the synthesis of sphingolipids and glycerophospholipids to produce cell membranes and signaling molecules. Receptor for activated C-kinase 1 (RACK1; also known as small ribosomal subunit protein) is an intracellular scaffolding protein involved in signaling pathways. Whether such lipid metabolism is regulated by RACK1 is unknown. Here, integrated spatially resolved metabolomics and spatial transcriptomics revealed that accumulation of lipids in cervical cancer (CC) samples correlated with overexpression of RACK1, and RACK1 promoted lipid synthesis in CC cells. Chromatin immunoprecipitation verified binding of sterol regulatory element-binding protein 1 (SREBP1) to acetyl-CoA carboxylase (ACC) and fatty acid synthase (FASN) promoters. RACK1 enhanced de novo FA synthesis by upregulating expression of sterol regulatory element binding transcription factor 1 (SREBP1) and lipogenic genes FASN and ACC1. Co-immunoprecipitation and western blotting revealed that RACK1 interacted with protein kinase B (AKT) to activate the AKT/mammalian target of rapamycin (mTOR)/SREBP1 signaling pathway to promote FA synthesis. Cell proliferation and apoptosis experiments suggested that RACK1-regulated FA synthesis is key in the progression of CC. Thus, RACK1 enhanced lipid synthesis through the AKT/mTOR/SREBP1 signaling pathway to promote the growth of CC cells. RACK1 may become a therapeutic target for CC.

Maternal Broccoli Powder Intake Ameliorates Insulin Resistance and Inflammation via AMPK/mTOR Pathway in the Livers of High-Fructose-Fed Male Rat Offspring Exposed to Maternal Protein Restriction.

Sub-optimal prenatal conditions such as maternal undernutrition during pregnancy and lactation posit high risks of adult metabolic diseases. High fructose intake causes insulin resistance and liver inflammation contributing to metabolic diseases. However, food-based preventive measure for these metabolic diseases in the offspring is under-researched. This study aims to investigate the effect of maternal broccoli powder (BP) intake during lactation on insulin resistance and liver inflammation in high-fructose-diet-fed adult male offspring exposed to maternal protein restriction. Pregnant Wistar rats are provided normal protein (NP) or low protein (LP) diets and 0% or 0.74% BP-containing NP diets and 0% or 0.74% BP-containing LP diet during lactation. At weaning, offspring receiving water (W) or 10% fructose solution (Fr) are assigned into six groups: NP/NP/W, NP/NP/Fr, NP/NPBP/Fr, LP/LP/W, LP/LP/Fr, and LP/LPBP/Fr. At week 13, plasma insulin, macrophage infiltration, activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR) phosphorylation, and autophagy flux markers are examined. LP/LPBP/Fr shows lower insulin levels and Homeostatic model assessment for insulin resistance (HOMA-IR) values than LP/LP/Fr. Liver macrophage infiltration are decreased in LP/LPBP/Fr. LP/LPBP/Fr exhibits upregulated AMPK phosphorylation, downregulated mTOR phosphorylation, and increased Microtubule-associated protein1A/1B-light chain 3B-II (LC3B-II) levels. Maternal BP intake during lactation ameliorates insulin resistance and inflammation in the livers of adult offspring on a high-fructose diet from LP mothers.

The mTOR Pathway: A Common Link Between Alzheimer’s Disease and Down Syndrome

Down syndrome (DS) is a chromosomal condition that causes many systemic dysregulations, leading to several possible age-related diseases including Alzheimer’s disease (AD). This may be due to the triplication of the Amyloid precursor protein (APP) gene or other alterations in mechanistic pathways, such as the mTOR pathway. Impairments to upstream regulators of mTOR, such as insulin, PI3K/AKT, AMPK, and amino acid signaling, have been linked to amyloid beta plaques (Aβ) and neurofibrillary tangles (NFT), the most common AD pathologies. However, the mechanisms involved in the progression of pathology in human DS-related AD (DS-AD) are not fully investigated to date. Recent advancements in omics platforms are uncovering new insights into neurodegeneration. Genomics, spatial transcriptomics, proteomics, and metabolomics are novel methodologies that provide more data in greater detail than ever before; however, these methods have not been used to analyze the mTOR pathways in connection to DS-AD. Using these new techniques can unveil unexpected insights into pathological cellular mechanisms through an unbiased approach.

Potential liquid biopsy markers of exosomal microRNAs in renal interstitial fibrosis blood and urine

ABSTRACT Objective: To explore more and better liquid biopsy markers of exosomal microRNAs (exo-miRNAs) in renal interstitial fibrosis (RIF) and to preliminary investigate the biological functions and signaling pathways involved in these markers. MATERIALS AND METHODS: High-throughput miRNA sequencing was performed on blood and urine exo-miRNAs from three RIF patients and three healthy volunteers, and differential expression analysis and bioinformatic processing were performed. Results: There were 13 differentially expressed exo-miRNA (DEexo-miRNA) between RIF and healthy blood, and 20 DEexo-miRNAs in urine. These were various DEexo-miRNAs in different specimens, and the former included PC-3p-213532_58, hsa-miR-338-5p_R-1, PC-5p-34127_410, pal-miR-9993a-3p_L+2R-1, and hsa-miR-26a-1-3p with intermediate expression levels; the latter involved hsa-miR-126-3p, hsa-miR-217-5p, hsa-miR-199b-3p_R-1, mmu-miR-5106_R-4_1ss1AG, and PC-5p-39041_356, and others, while hsa-miR-378a-3p, hsa-miR-143-3p_R+1, hsa-miR-183-5p, hsa-miR-126-3p, hsa-miR-155-5p_R-1, mmu-miR-5106_R-4_1ss1AG, hsa-miR-126-5p, and hsa-miR-199b-3p_R-1 had high expression levels. Bioinformatics analysis of the up-regulated DEmiRNA with high expression in urine showed that there are 291 target corresponding mRNAs for six of eight DEexo-miRNAs, with mmu-miR-5106_R-4_1ss1AG and hsa-miR-199b-3p_R-1 having no target gene found in TargetScan and miRanda. GO annotation revealed that GO:0005515 (protein binding) had the lowest P value, involving the most genes. KEGG analysis revealed that the signaling included the mTOR signaling pathway, autophagy - animal, etc., and hsa05200 (pathways in cancer) had a lower P value, involving the most genes. Conclusions: Urine is a better sample for RIF exo-miRNA detection than blood. Urinary exosomal hsa-miR-143-3p_R+1, hsa-miR-183-5p, hsa-miR-126-3p, mmu-miR-5106_R-4_1ss1AG, hsa-miR-126-5p, and hsa-miR-199b-3p_R-1 are novel liquid biopsy markers for RIF. These DEexo-miRNA may be associated with the occurrence and development of RIF and may participate in specific biological processes by regulating the expression of their target mRNA. Further research may require exploring the specific functions and mechanisms of these miRNAs in RIF, as well as whether they can serve as diagnostic or therapeutic targets for RIF.

SMAC mimetic BV6 acts in synergy with mTOR inhibitor to increase cisplatin sensitivity in ovarian cancer.

The objective of this study is to observe the antitumor efficacy of the second mitochondria-derived activator of caspases (SMAC) mimetic bivalent smac mimetic (BV6) in combination with target of rapamycin (mTOR) inhibitor on DDP (cisplatin) sensitivity. Ovarian cancer cells were exposed to cisplatin, BV6, DDP + BV6, and DDP + BV6 + mTOR inhibitor Rapamycin. Using proteomics and bioinformatics, protein expression profiles in ovarian cancer were determined. Bagg Albino color nude mice were treated with DDP or BV6 alone or in combination, or BV6 + DDP + Rapamycin. The effects of different treatments on ovarian cancer cells and tumor growth were evaluated in vivo and in vitro. Proteomics and bioinformatics analysis revealed significant changes of protein kinase (AKT)/mTOR pathway. Consistently, western blot data indicated that AKT/mTOR axis was gradually activated in BV6-treated ovarian cancer cells and attenuated the cytotoxic effect of BV6. Functional assays showed that DDP or BV6 treatment alone significantly enhanced the sensitivity and inhibited the migration of ovarian cancer cells, but without any synergistic effects. In addition, combination with BV6 and mTOR inhibitor Rapamycin significantly decreased cell viability and inhibited migration of ovarian cancer cells exposed to DDP. Consistently, the xenograft model showed that co-treatment with Rapamycin with BV6 had significantly suppressed tumor growth and metastasis. Our study demonstrated that SMAC analogue BV6 exhibits a strong anticancer effect on ovarian cancer in vitro and in vivo. Combination with Rapamycin overcomes the activation of mTOR pathway by BV6 and increases the chemosensitivity to DDP. These data suggest a potential application of triple combination with DDP + BV6 + Rapamycin in clinical management of ovarian cancer.

Irisin suppresses PDGF-BB-induced proliferation of vascular smooth muscle cells in vitro by activating AMPK/mTOR-mediated autophagy.

Restenosis is a pivotal factor that restricts the efficacy of coronary artery bypass grafting. Inhibition of vascular smooth muscle cells (VSMCs) proliferation can improve intimal hyperplasia and lumen stenosis. Irisin, a polypeptide secreted by muscle cells, has been demonstrated to have a protective role in various cardiovascular diseases. However, the effect and mechanism of irisin on VSMCs proliferation and phenotype switching remain unclear. Cell proliferation ability was assessed using the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and 5-ethynyl-2'-deoxyuridine (EdU) incorporation. Cell cycle analysis was performed using flow cytometry, while expression levels of contractile and synthesis-related proteins were determined through RT-qPCR and Western blot. The VSMCs were infected with an adenovirus carrying GFP-LC3, and the proportion of cells showing positive expression was assessed. Additionally, the formation of autophagic lysosomes in cells was observed through transmission electron microscopy. In this study, we have demonstrated the inhibitory effects of irisin on the proliferation and phenotypic transition of platelet-derived growth factor-BB (PDGF-BB)-induced VSMCs. More importantly, we have discovered that irisin can activate the AMP-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) signaling pathway to mediate autophagy in PDGF-BB-induced VSMCs. The inhibitory effect of irisin on PDGF-BB-induced VSMCs proliferation was significantly attenuated by the AMPK inhibitor, Compound C. Conversely the mTOR inhibitor, rapamycin further enhanced the inhibitory effect of irisin on PDGF-BB induced VSMCs proliferation. In conclusion, our findings suggest that irisin effectively suppresses the aberrant proliferation of VSMCs following PDGF-BB stimulation by modulating autophagy levels through the AMPK/mTOR signaling pathway.

Analysis of SLC genes alternative splicing identifies the SLC7A6 RI isoform as a therapeutic target for colorectal cancer.

Alternative splicing (AS), a crucial mechanism in post-transcriptional regulation, has been implicated in diverse cancer processes. Several splicing variants of solute carrier (SLC) transporters reportedly play pivotal roles in tumorigenesis and tumor development. However, an in-depth analysis of AS landscapes of SLCs in colon adenocarcinoma (COAD) is lacking. Herein, we analyzed data from The Cancer Genome Atlas and identified 1215 AS events across 243 SLC genes, including 109 differentially expressed AS (DEAS) events involving 62 SLC genes in COAD. Differentially spliced SLCs were enriched in biological processes, including transmembrane transporter activity, transporter activity, ferroptosis, and choline metabolism. In patients with COAD, tumor tissues exhibited higher expression of longer mitochondrial carrier SLC25A16 isoforms than adjacent normal tissues, consistent with bioinformatics analysis. Protein-coding sequences and transmembrane helices of survival-related DEAS were predicted, revealing that shifts in splicing sites altered the number and structure of their transmembrane proteins. We developed a prognostic risk model based on the screened 6-SLC-AS (SLC7A6_RI_37208 (SLC7A6-RI), SLC11A2_AP_21724, SLC2A8_ES_87631, SLC35B1_AA_42317, SLC39A11_AD_43204, and SLC7A8_AP_26712). Knockdown of the intronic region of SLC7A6-RI isoform enhanced colon cancer cell proliferation. Invivo, knockdown of the intronic region of SLC7A6-RI isoform enhanced tumor growth in colon cancer. Mechanistically, si-SLC7A6-RI isoform exerted oncogenic effects by activating the PI3K-Akt-mTOR signaling pathway and promoting cell proliferation, evidenced by increased expression of key regulators Phosphorylated Mammalian Target of Rapamycin (p-mTOR) and a cell proliferation marker Proliferating Cell Nuclear Antigen (PCNA) using western blotting. Our study elucidated SLC-AS in COAD, highlighting its potential as a prognostic and therapeutic target and emphasizing the suppressive influence of SLC7A6-RI in colon cancer progression.

MTOR in the Development of Hypoxic Pulmonary Hypertension Associated with Cardiometabolic Risk Factors.

The pathophysiology of pulmonary hypertension is complex and multifactorial. It is a disease characterized by increased pulmonary vascular resistance at the level due to sustained vasoconstriction and remodeling of the pulmonary arteries, which triggers an increase in the mean pulmonary artery pressure and subsequent right ventricular hypertrophy, which in some cases can cause right heart failure. Hypoxic pulmonary hypertension (HPH) is currently classified into Group 3 of the five different groups of pulmonary hypertensions, which are determined according to the cause of the disease. HPH mainly develops as a product of lung diseases, among the most prevalent causes of obstructive sleep apnea (OSA), chronic obstructive pulmonary disease (COPD), or hypobaric hypoxia due to exposure to high altitudes. Additionally, cardiometabolic risk factors converge on molecular mechanisms involving overactivation of the mammalian target of rapamycin (mTOR), which correspond to a central axis in the development of HPH. The aim of this review is to summarize the role of mTOR in the development of HPH associated with metabolic risk factors and its therapeutic alternatives, which will be discussed in this review.

Methionine supply during mid-gestation modulates the bovine placental mTOR pathway, nutrient transporters, and offspring birth weight in a sex-specific manner.

The mechanistic target of rapamycin (mTOR) predominantly regulates the expression and activity of placental nutrient transporters. The mTOR pathway can be activated by several nutrients, including the essential amino acid methionine. Additionally, previous research in nonruminant animals suggests that mTOR is influenced in a sexually dimorphic manner. In bovine, there is limited understanding of how maternal nutrition and offspring sexual dimorphism affect the placental transfer of nutrients. Thus, we investigated the effects of increasing the supply of dietary methionine to beef cattle heifers during mid-gestation on mTOR signaling, placental nutrient transporters, and fetal growth in male and female offspring. Forty purebred Angus heifers were used in a randomized complete block design experiment. From day 90 to 180 of gestation, heifers received a basal diet with no added methionine (CON, n = 20), or the basal diet plus 8.3g of rumen-protected methionine (MET, n = 20) per animal daily. All animals received a basal diet in the first and third trimesters of gestation. Cotyledonary tissue samples were collected at parturition and utilized to examine the mTOR pathway and nutrient transporters through protein and gene expression analysis. The offspring's body weight was measured at birth. Data were analyzed using a mixed model that included the fixed effect of treatment, offspring sex, their interactions, and the random effect of block. At day 170 of gestation, MET-supplemented heifers showed higher plasma concentrations of methionine and glutamate (P < 0.01) and lower glycine and proline levels (P ≤ 0.01) compared to the CON group. A treatment × sex interaction was observed for calf birth weight (P = 0.03). In heifers that delivered male calves, MET supplementation increased the birth weight of the calves (P < 0.01). However, the dietary treatments had no effect on the birth weight of female calves (P = 0.32). The increase in birth weight of male calves from MET-fed heifers resembles with the upregulation of placental mTOR and phosphorylated mTOR (P ≤ 0.03), as well as the amino acid transporters SLC1A5, SLC7A5, SLC38A6, and SLC38A11, and the glucose transporters SLC2A1 and SLC2A8 (P ≤ 0.05). Our findings suggest that increasing the supply of methionine to beef heifers during mid-gestation can modulate placental nutrient transport and fetal growth in a sex-dependent manner and that these effects are mediated, at least in part, by the mTOR pathway.

Multi-omics approach to reveal follicular metabolic changes and their effects on oocyte competence in PCOS patients.

Polycystic ovary syndrome (PCOS) is a common heterogeneous disorder linked with endocrine and metabolic disturbances. The underlying mechanism of PCOS, especially its effect on oocyte competence, remains unclear. The study aimed to identify abnormal follicular metabolic changes using a multi-omics approach in follicular fluid from PCOS patients and to determine their effects on oocyte competence. A total of 36 women with PCOS and 35 women without PCOS who underwent in vitro fertilization and embryo transfer were included in the study. Cumulus cells and follicular fluid samples were collected. Follicular fluid samples underwent metabolomic analysis, while cumulus cell clusters from the same patients were assessed using transcriptomic analysis. Clinical information of patients and assisted reproductive technology (ART) results were recorded. Transcriptomics and metabolomics were integrated to identify disrupted pathways, and receiver operation characteristics (ROC) analysis was conducted to identify potential diagnostic biomarkers for PCOS. Pearson correlation analysis was conducted to assess the relationship between metabolites in follicular fluid and oocyte competence (fertilization and early embryo development potential). Through multi-omics analysis, we identified aberrantly expressed pathways at both transcriptional and metabolic levels, such as the citrate cycle (TCA cycle), oxidative phosphorylation, the cAMP signaling pathway, the mTOR signaling pathway, and steroid hormone biosynthesis. Ten candidate metabolites were identified based on metabolic profiling data from these altered pathways. Phytic acid, succinic acid, 2'-deoxyinosine triphosphate, and 4-trimethylammoniobutanoic acid in the follicular fluid exhibited high specificity and sensitivity in distinguishing PCOS. Among these metabolites, L-arginine showed a negative correlation with the 2PN fertilization rate and cleavage rate, while estrone sulfate showed a negative correlation with the high-quality embryo rate in the in-vitro fertilization (IVF) cycle. We have conducted a preliminary study of a novel metabolic signature in women with PCOS using a multi-omics approach. The alterations in key metabolic pathways may enhance our understanding of the pathogenesis of PCOS.

Glycolysis-mTORC1 crosstalk drives proliferation of patient-derived endometrial cancer spheroid cells with ALDH activity

Cancer stem cells are associated with aggressive phenotypes of malignant tumors. A prominent feature of uterine endometrial cancer is the activation of the PI3K–Akt–mTOR pathway. In this study, we present variations in sensitivities to a PI3K–Akt–mTORC1 inhibitor among in vitro endometrial cancer stem cell-enriched spheroid cells from clinical specimens. The in vitro sensitivity was consistent with the effects observed in in vivo spheroid-derived xenograft tumor models. Our findings revealed a complementary suppressive effect on endometrial cancer spheroid cell growth with the combined use of aldehyde dehydrogenase (ALDH) and PI3K–Akt inhibitors. In the PI3K–Akt–mTORC1 signaling cascade, the influence of ALDH on mTORC1 was partially channeled through retinoic acid-induced lactate dehydrogenase A (LDHA) activation. LDHA inhibition was found to reduce endometrial cancer cell growth, aligning with the effects of mTORC1 inhibition. Building upon our previous findings highlighting ALDH-driven glycolysis through GLUT1 in uterine endometrial cancer spheroid cells, curbing mTORC1 enhanced glucose transport via GLUT1 activation. Notably, elevated LDHA expression correlated with adverse clinical survival and escalated tumor grade, especially in advanced stages. Collectively, our findings emphasize the pivotal role of ALDH–LDHA–mTORC1 cascade in the proliferation of endometrial cancer. Targeting the interaction between mTORC1 and ALDH-influenced glycolysis holds promise for developing novel strategies to combat this aggressive cancer.

Suppressive Effects of Arriheuk Wheat Sprout Extract on Muscle Atrophy in Dexamethasone-Induced C2C12 Myotubes and a Mouse Model.

Skeletal muscle atrophy refers to the loss of muscle strength and mass due to decreased protein synthesis or increased protein degradation. Various conditions can cause muscle atrophy, including aging, heart disease, chronic illness, obstructive pulmonary disease, kidney failure, diabetes, AIDS, cancer, sepsis, and steroid use. Various natural materials have been studied for the prevention of muscle atrophy. In this study, we found that extracts from the sprouts of purple wheat, Arriheuk, prevented muscle atrophy in vitro and invivo. Arriheuk wheat sprouts extract inhibited the expression of muscle protein breakdown factors, which were increased by dexamethasone, and improved muscle strength. In C2C12 myotubes, Arriheuk wheat sprout extract (ARE) protected against dexamethasone-induced muscle atrophy by potentiating Akt/mammalian target of rapamycin and AMP-activated protein kinase (AMPK)/forkhead box O3 (AMPK/Foxo3) signaling and inhibiting the expression of Atrogin-1, muscle RING-finger protein-1 (MuRF1), and Myostatin. In addition, the administration of ARE in an animal model of muscle atrophy induced by dexamethasone prevented myocardial and muscle strength loss by regulating the expression of muscle atrophy-related factors by affecting AMPK/Foxo3 signaling. Taken together, these results suggest that Arriheuk wheat sprouts extract effectively alleviates muscle atrophy by regulating the synthesis and breakdown of muscle proteins.

Novel Compound Heterozygous Variants in the FAS Gene Lead to Fetal Onset of Autoimmune Lymphoproliferative Syndrome (ALPS).

FAS gene defects lead to autoimmune lymphoproliferative syndrome (ALPS), which is often inherited in an autosomal dominant and rarely in an autosomal recessive manner. We report a case of a newborn girl with novel compound heterozygous variants in FAS and reveal the underlying mechanism. Whole-exome sequencing (WES) was used to identify pathogenic variants. Multiparametric flow cytometry analysis, phosflow analysis, and FAS-induced apoptosis assays were used to explore the effects of the variants on FAS expression, apoptosis, and immunophenotype. The HEK293T cells were used to assess the impact of the variants on protein expression and FAS-induced apoptosis. The patient was born with hepatosplenomegaly, anemia, and thrombocytopenia. She also experienced COVID-19, rotavirus infection, herpes simplex virus infection, and severe pneumonia. The proportion of double-negative T cells (DNTs) was significantly elevated. Novel FAS compound heterozygous variants c.310T > A (p.C104S) and c.702_704del (p.T235del) were identified. The apoptotic ability of T cells was defective, and FAS expression on the surface of T cells was deficient. The T235del variant decreased FAS expression, and the C104S protein remained in the endoplasmic reticulum (ER) and could not translocate to the cell surface. Both mutations resulted in loss-of-function in terms of FAS-induced apoptosis in HEK293T cells. The DNTs were mainly terminally differentiated T (TEMRA) and CD45RA+HLA-DR+, with high expression of CD85j, PD-1, and CD57. The percentage of Th1, Tfh, and autoreactive B cells were significantly increased in the patient. The abnormal immunophenotyping was partially attenuated by sirolimus treatment. We identified two variants that significantly affect FAS expression or localization, leading to early disease onset of in the fetus. Abnormalities in the mTOR pathway are associated with a favorable response to sirolimus.

Failure of metabolic checkpoint control during late-stage granulopoiesis drives neutropenia in reticular dysgenesis

AbstractCellular metabolism is highly dynamic during hematopoiesis, yet the regulatory networks that maintain metabolic homeostasis during differentiation are incompletely understood. Herein, we have studied the grave immunodeficiency syndrome reticular dysgenesis caused by loss of mitochondrial adenylate kinase 2 (AK2) function. By coupling single-cell transcriptomics in samples from patients with reticular dysgenesis with a CRISPR model of this disorder in primary human hematopoietic stem cells, we found that the consequences of AK2 deficiency for the hematopoietic system are contingent on the effective engagement of metabolic checkpoints. In hematopoietic stem and progenitor cells, including early granulocyte precursors, AK2 deficiency reduced mechanistic target of rapamycin (mTOR) signaling and anabolic pathway activation. This conserved nutrient homeostasis and maintained cell survival and proliferation. In contrast, during late-stage granulopoiesis, metabolic checkpoints were ineffective, leading to a paradoxical upregulation of mTOR activity and energy-consuming anabolic pathways such as ribonucleoprotein synthesis in AK2-deficient cells. This caused nucleotide imbalance, including highly elevated adenosine monophosphate and inosine monophosphate levels, the depletion of essential substrates such as NAD+ and aspartate, and ultimately resulted in proliferation arrest and demise of the granulocyte lineage. Our findings suggest that even severe metabolic defects can be tolerated with the help of metabolic checkpoints but that the failure of such checkpoints in differentiated cells results in a catastrophic loss of homeostasis.