mTOR Signaling Research Articles

Agrimonolide Inhibits the Malignant Progression of Non-small Cell Lung Cancer and Induces Ferroptosis through the mTOR Signaling Pathway.

Non-Small Cell Lung Cancer (NSCLC), a prevalent type of lung cancer, has a poor prognosis and contributes to a high mortality rate. Agrimonolide, which belongs to the Rosaceae family, possesses various biomedical activities. This study aimed to explore the efficacy and mechanism of agrimonolide in NSCLC. The viability, proliferation, and tumor-forming ability of A549 cells were detected using the Cell Counting Kit-8 assay (CCK-8) assay, EdU staining, and colony formation assay. The cell cycle was detected using flow cytometry. Cell migration and invasion were detected using wound healing and transwell assays. Western blot was used to detect Epithelial-Mesenchymal Transition (EMT)-, ferroptosis-, and mechanistic targets of rapamycin (mTOR) signaling pathway-related proteins. Lipid peroxidation was detected using the thiobarbituric acid reactive substances (TBARS) assay kit, while lipid Reactive Oxygen Species (ROS) was detected using a BODIPY 581/591 C11 kit. The level of Fe2+ was detected using corresponding assay kits. In this study, agrimonolide with varying concentrations (10, 20, and 40 μM] could inhibit the proliferation, induce cycle arrest, suppress metastasis, induce ferroptosis, and block the mTOR signaling pathway in NSCLC cells. To further reveal the mechanism of agrimonolide associated with the mTOR signaling pathway in NSCLC, mTOR agonist MHY1485 (10 μM) was used to pre-treat A549 cells, and functional experiments were conducted again. It was found that the protective effects of AM on NSCLC cells were all partially abolished by MHY1485 pre-treatment. Agrimonolide inhibited the malignant progression of NSCLC and induced ferroptosis by blocking the mTOR signaling pathway, thus indicating the potential of agrimonolide as a prospective candidate for treating NSCLC.

Inhibitors of the mTOR signaling pathway can play an important role in breast cancer immunopathogenesis.

This study explores the critical role of inhibitors targeting the mammalian target of rapamycin (mTOR) signaling pathway in breast cancer research and treatment. The mTOR pathway, a central regulator of cellular processes, has been identified as a crucial factor in the development and progression of breast cancer. The essay explains the complex molecular mechanisms through which mTOR inhibitors, such as rapamycin and its analogs, exert their anticancer effects. These inhibitors can stop cell growth, proliferation, and survival in breast cancer cells by blocking critical signaling pathways within the mTOR pathway. Furthermore, the essay discusses the implications of using mTOR inhibitors as a comprehensive therapeutic strategy. It emphasizes the potential benefits of combining mTOR inhibitors with other treatment approaches to enhance the effectiveness of breast cancer treatment. The evolving landscape of breast cancer research underscores the significance of mTOR as a therapeutic target and highlights ongoing efforts to improve and optimize mTOR inhibitors for clinical use. In conclusion, the essay asserts that inhibitors of the mTOR signaling pathway offer a promising approach in the fight against breast cancer. These inhibitors provide a focused and effective intervention targeting specific dysregulations within the mTOR pathway. As research advances, the integration of mTOR inhibitors into customized combination therapies holds excellent potential for shaping a more effective and personalized approach to breast cancer treatment, ultimately leading to improved outcomes for individuals affected by this complex and diverse disease.

Senolytics Enhance the Longevity of Caenorhabditis elegans by Altering Betaine Metabolism.

Aging triggers physiological changes in organisms that are tightly linked to metabolic changes. Senolytics targeting many fundamental aging processes are currently being developed. However, the host metabolic response to natural senescence and the molecular mechanism underlying the antiaging benefits of senolytics remain poorly understood. In this study, we investigated metabolic changes during natural senescence based on the Caenorhabditis elegans model and pinpointed potential biomarkers linked to the benefits of senolytics. These results suggest that age-dependent metabolic changes during natural aging occur in C elegans. Betaine was identified as a crucial metabolite in the natural aging process. We explored the metabolic effects of aging interventions by administering 3 antiaging drugs-metformin, quercetin, and minocycline-to nematodes. Notably, betaine expression significantly increased under the 3 antiaging drug treatments. Our findings demonstrated that betaine supplementation extends lifespan, primarily through pathways associated with the forkhead box transcription factor (FoxO) signaling pathway, the p38-mitogen-activated protein kinase (MAPK) signaling pathway, autophagy, the longevity regulating pathway, and the target of rapamycin (mTOR) signaling pathway. In addition, autophagy and free radicals are altered in betaine-treated nematodes. Overall, we found that betaine is a critical metabolite during natural aging and that senolytics extend the lifespan of nematodes by increasing betaine levels and promoting autophagy and antioxidant activity. This finding suggests that betaine could be a novel therapeutic target for promoting longevity.

The eIF3a translational control axis in the Wnt/β-catenin signaling pathway and colon tumorigenesis

Translational initiation in protein synthesis is an important regulatory step in gene expression and its dysregulation may result in diseases such as cancer. Translational control by eIF4E/4E-BP has been well studied and contributes to mTOR signaling in various biological processes. Here, we report a novel translational control axis in the Wnt/β-catenin signaling pathway in colon tumorigenesis by eIF3a, a Yin-Yang factor in tumorigenesis and prognosis. We show that eIF3a expression is upregulated in human colon cancer tissues, pre-cancerous adenoma polyps, and associates with β-catenin level and APC mutation in human samples, and that eIF3a overexpression transforms intestinal epithelial cells. We also show that eIF3a expression is regulated by the Wnt/β-catenin signaling pathway with an active TCF/LEF binding site in its promoter and that eIF3a knockdown inhibits APC mutation-induced spontaneous colon tumorigenesis in APCmin/+ mice. Together, we conclude that eIF3a upregulation in colon cancer is due to APC mutation and it participates in colon tumorigenesis by adding a translational control axis in Wnt/β-catenin signaling pathway and that it can serve as a potential target for colon cancer intervention.

Pyroptosis-related gene GSDMC indicates poor prognosis and promotes tumor progression by activating the AKT/mTOR pathway in lung squamous cell carcinoma.

Lung squamous cell carcinoma (LUSC) is one of the most common malignant tumors of the respiratory. Pyroptosis plays an essential role in cancer, but there is limited research investigating pyroptosis in LUSC. In this study, pyroptosis-related genes were observed to have extensive multiomics alterations in LUSC through analysis of the TCGA database. Utilizing machine learning for selection and verifying expression levels, GSDMC was chosen as the critical gene for further experiments. Our research found that GSDMC is overexpressed in LUSC tissues and cells, and is associated with poor prognosis. Knockdown of GSDMC in LUSC inhibits cell proliferation, invasion, metastasis, chemotherapeutic sensitivity, and reduced tumor formation in nude mice, accompanied by downregulation of proliferative and EMT-related protein expression. However, these effects were counteracted in cells where GSDMC is overexpressed. Mechanistically, the oncogenic role of GSDMC is primarily achieved through the activation of the AKT/mTOR pathway, and this effect can be significantly reversed by rapamycin. Finally, SMAD4's interaction with the promoter region of GSDMC results in the suppression of GSDMC expression. In summary, our study through bioinformatics and experimental approaches not only proves that SMAD4 regulates the protumorigenic role of GSDMC through transcriptional targeting, but also indicates the possibility of developing the SMAD4/GSDMC/AKT/mTOR signaling axis as a potential biomarker and treatment target for LUSC.

Polydatin protects against articular cartilage degeneration by regulating autophagy mediated by the AMPK/mTOR signaling pathway.

Knee osteoarthritis (KOA) is one of the leading causes of disability. Polydatin has a potential effect on KOA treatment but the therapeutic mechanism is not clear. This study aims to investigate the therapeutic action of polydatin in KOA and its mechanism in activating autophagy via the AMP-activated protein kinase (AMPK)/mTOR signaling pathway. After a KOA rat model was established by anterior cruciate ligament transection surgery, model rats were treated with polydatin 40 mg/kg for 30 days. Subsequently, cartilage tissues were collected, and hematoxylin-eosin (HE), Safranin-O, and TUNEL staining, and western blotting were performed to evaluate the pathological damage and autophagy-related protein expression. Then, human chondrocyte C28/I2 cells were stimulated with lipopolysaccharide (LPS), and the effects of polydatin on C28/I2 cell viability, apoptosis, and autophagy-related protein expression were detected by MTT, Flow Cytometry, and western blot. In addition, an AMPK inhibitor (Dorsomorphin 2HCl) was used to probe the cell proliferation and apoptosis of polydatin-administered C28/I2 cells. Polydatin ameliorated the pathological damage in rat cartilage tissues and inhibited cell apoptosis in KOA rats. Meanwhile, in C28/I2 cells, polydatin promoted viability and reduced apoptosis. In addition, the protein expression of collagen II, LC3II/LC3I, Beclin-1, and p-AMPK/AMPK were upregulated, and p62 and p-mTOR/mTOR were downregulated by polydatin treatment. Interestingly, relative results showed that the protective effect of polydatin in LPS-stimulated-C28/I2 cells was blocked by the AMPK/mTOR inhibitor, dorsomorphin 2HCl. Our research showed that polydatin reduced apoptosis and activated autophagy both in vivo and in vitro by the AMPK/mTOR signaling pathway to protect against KOA, which provided the basis for further investigation into the potential therapeutic impact of polydatin on KOA.

First time evaluation of myocardium microRNA profile in Anderson-Fabry disease: implications in the pathological processes

Abstract Background Anderson Fabry disease (AFD) is an X-linked lysosomal disorder, characterized by progressive sphingolipid storage and organ dysfunction. Cardiac involvement is characterized by left ventricular hypertrophy, inflammation and fibrosis and is leading cause of mortality. MicroRNAs (miRNAs) are emerging as promising biomarkers in medicine, as they are dysregulated in many human diseases, offering opportunities to improve our understanding of disorders and discover new therapeutic targets. However, so far, only a few studies have evaluated the role of miRNAs in Fabry disease, and cardiac tissue miRNAs have never been assessed. Purpose To determine the specific tissue miRNA profile analyzing myocardial tissue of AFD patients and to evaluate their relationship with the severity of cardiac involvement. Methods 19 AFD patients (10 females [53%]; median age 53 years [IQR 43-63]) undergoing right ventricular endomyocardial biopsy (n=15) or surgical septal myectomy (n=4), standard cardiac magnetic resonance (1.5T, cines for maximum wall thickness (MWT) and indexed LV mass (LVMi) calculation) and high-sensitivity Troponin I (TnI) dosage were included and compared to 7 endomyocardial biopsies of controls. Myocardial samples were fixed in formalin and embedded in paraffin. RNA was extracted from 3-5 slides of tissue and used to generate small RNA libraries (Qiagen) for Next Generation Sequencing analysis on Illumina sequencer. Raw data were normalized and analyzed using DEseq2 pipeline. Correlations were performed using Pearson r; a p < 0.05 was considered statistically significant. Results In AFD group median MWT was 13 mm [IQR 8-17], LVMi was 72 g/m2 [IQR 46-97]. TnI was increased in 9 patients (47%) and NT-proBNP in 8 (42%). 6 patients were on specific AFD treatment. We identified 9 miRNAs differentially expressed in AFD patients compared to controls; miRPath analysis revealed that these miRNAs are associated to pathways involved in AFD pathogenesis (autophagy and mTOR signalling, HIF-1, apoptosis, TGF-beta signalling and inflammation) (figure 1). Moreover, we found 10 miRNAs that were differentially expressed in maximal wall thickness (<10 mm, 10-15 mm, >15 mm) groups (figure 2), in particular 3 miRNAs that progressively increased at the increasing of thickness. Among these miRNAs, miR-21-5p showed the strongest correlation with myocardial hypertrophy (r=0.869, p value<0.001 for MWT; r=0.905, p<0.001 for LVMi) and with cardiac damage (r=0.831, p<0.001 for TnI). Additionally, miR-21-5p had a modest correlation with age (r=0.518, p=0.05) and did not differ between patients on specific AFD treatment and patients not treated (p=0.660). Conclusions This study for the first time evaluated the myocardial miRNA profile in AFD patients and identified miR-21-5p as a cardiac biomarker correlating with clinical heart involvement, both in terms of left ventricular hypertrophy (MWT, LVMi) and myocardium damage (troponin).Figure 1Figure 2

Identification and validation of circulating microRNAs as biomarkers for heart failure with preserved ejection fraction

Abstract Background Heart failure (HF) is a syndrome due to cardiac insufficiency, manifested by excessive volume overload, increased sympathetic activity, and circulatory redistribution [1]. Heart failure with preserved ejection fraction (HFpEF) accounts for approximately 40%-50% of the total HF events, and its development is often accompanied by various complications, including hypertension, obesity, and metabolic syndrome. Biomarker associations in heart failure with reduced ejection fraction were mostly cardiac stretch based, while many biomarkers of HFpEF are also associated with inflammation [2]. To date, treatments that effectively improve the clinical prognosis of HFpEF are relatively limited, thus HFpEF remains one of the challenges that needs to be further explored. A full understanding of the molecular mechanisms of HFpEF is essential to improve the early diagnosis, treatment and prognosis of these patients. Purpose The study aims to explore key circulating miRNAs and related molecular pathways in HFpEF patients through bioinformatics analysis and machine learning, and to further validate them using a double-hit HFpEF mouse model. Methods We downloaded HF datasets including circulating miRNA expression profiles from the GEO database. LASSO regression, SVM-RFE, Random Forest and XGboost algorithm were conducted to identify key miRNAs for diagnostic model construction. We used R software, GO, KEGG and Cytoscape to better understand the functions of key miRNA targets. Besides, the mRNA-miRNA interaction networks were predicted by starbase. We also constructed a HFpEF mouse model subjected to high fat diet and L-NAME (0.5 g/L) in drinking water to discover the correlation between the screened circulating miRNA and HFpEF. Results After differential expression analysis of the combined HFpEF dataset, we identified 37 differentially circulating miRNAs, of which 15 were down-regulated and 22 were up-regulated. Subsequently, we screened by machine learning and identified 4 key miRNAs that may be involved in the progression of HFpEF, including hsa-miR-645, hsa-miR-296-5p, hsa-miR-199b-5p, and hsa-miR-509-3-5p. We validated these miRNAs based on their expression, and the ROC plots suggest that these miRNAs may have diagnostic capability in HFpEF. The results of GO and KEGG enrichment analyses showed that the target genes of the differentiated miRNAs were mainly enriched in the MAPK signaling pathway, mTOR signaling pathway, protein processing in endoplasmic reticulum, hippo signaling pathway, cell cycle, Foxo signaling pathway, hypertrophic cardiomyopathy, dilated cardiomyopathy, and circadian rhythm. The mRNA-miRNA interaction networks suggested that TMEM135 was regulated by both has-miR-199b-5p and hsa-miR-296-5p. The RT-PCR results also suggested that miR-199b-5p was upregulated in the HFpEF mice. Conclusion We validated 4 circulating miRNAs with strong correlation to HFpEF, which provide a more reliable basis for pre-symptomatic diagnosis.

Selective Cytotoxicity and Gene Expression Profiles in Response to Methanolic Extract of Phyllanthus amarus Extract against MCF-7 Breast Cancer Cells

Background Breast cancer, a malignant tumor, is the most common cancer type among women worldwide. Conventional chemotherapy treatments for breast cancer often cause adverse side effects in normal tissues and can lead to treatment failure. Plant-derived natural compounds offer an effective alternative with fewer side effects for cancer patients. Phyllanthus amarus is a medicinal plant widely distributed in China, India, and Brazil and reported to be used for the treatment of various types of cancer. Purpose This study was aimed to investigate the anticancer efficacy of methanolic extract of P. amarus against MCF-7 breast cancer cells. Methods We probed the anticancer activity in MCF-7 breast cancer cells by isolating the methanolic extract of P. amarus leaf extract (MEPA). The standard chemotherapy drug docetaxel is combined with MEPA to increase the drug efficacy. Moreover, the intracellular reactive oxygen species (ROS), alterations in mitochondrial membrane potential (MMP), nuclear condensation, and apoptotic activation were investigated in MCF-7 cells. Additionally, the customized PCR array comprising of cell cycle, apoptosis, mTOR, and JAK-STAT-related genes was studied during different MEPA treatments. Results In the MCF-7 breast cancer cells, the MEPA and docetaxel combination demonstrated strong cytotoxicity, with IC50 values of 45 and 2.6 µg/mL, respectively. MEPA and docetaxel together exhibited enhanced alterations in MMP and increased generation of ROS in MCF-7 cells. Furthermore, the combination of docetaxel with MEPA induces nuclear condensation and apoptotic cell death. During MEPA treatment, the gene expression profiles in MCF-7 cells were accessed. The JAK-STAT, mTOR signaling pathway, apoptosis, and cell growth-related genes were strongly affected by the dose-dependent administration of MEPA. Conclusion This study suggests that MEPA could be a useful alternative treatment for breast cancer. When combined with traditional chemotherapy, MEPA might offer better results with fewer side effects. More in vivo studies are needed to confirm MEPA’s effectiveness in animal models.

Aging alters the effect of adiponectin receptor signaling on bone marrow-derived mesenchymal stem cells.

Adiponectin receptor signaling represents a promising therapeutic target for age-related conditions such as osteoporosis and diabetes. However, the literature presents conflicting evidence regarding the role of adiponectin signaling in bone homeostasis and fracture repair across different health states, ages, and disease conditions. These inconsistencies may arise from the complex endocrine and paracrine feedback mechanisms regulating adiponectin, as well as the variability in adiponectin isoforms and receptor expressions. In this study, we observed differential expression of adiponectin receptors in the bone marrow (BM) of aged mice, characterized by elevated levels of adiponectin receptor 2 and reduced levels of receptor 1, as corroborated by both single-cell sequencing and invivo staining. Additionally, circulating levels of adiponectin and its local expression were significantly higher in aged mice compared to younger counterparts. Treatment with adiponectin receptor agonist, AdipoRon, enhanced bone regeneration and repair in young mice by promoting osteogenesis and reducing osteoclastogenesis. Conversely, in aged mice, AdipoRon treatment led to cellular senescence, delayed bone repair, and inhibited osteogenic activity. Notably, the adiponectin receptor 1-Wnt and adiponectin receptor 2-MAPK and mTOR signaling pathways were differentially activated in AdipoRon-treated BM mesenchymal stem cells from young and aged mice. Additionally, the NF-κB, and AKT pathways were consistently downregulated in BM macrophages of both age groups following AdipoRon administration. In conclusion, aging significantly modulates the impact of adiponectin receptor signaling on BM mesenchymal stem cells. This modulation is potentially attributable to changes in receptor transcription and distribution, as well as differential activation of downstream signaling pathways.

GCN2-SLC7A11 axis coordinates autophagy, cell cycle and apoptosis and regulates cell growth in retinoblastoma upon arginine deprivation

BackgroundArginine deprivation was previously shown to inhibit retinoblastoma cell proliferation and induce cell death in vitro. However, the mechanisms by which retinoblastoma cells respond to arginine deprivation remain to be elucidated.MethodsThe human-derived retinoblastoma cell lines Y79 and WERI-Rb-1 were subjected to arginine depletion, and the effects on inhibiting cell growth and survival were evaluated. This study investigated potential mechanisms, including autophagy, cell cycle arrest and apoptosis. Moreover, the roles of the general control nonderepressible 2 (GCN2) and mechanistic target of rapamycin complex 1 (mTORC1) signaling pathways in these processes were examined.ResultsWe demonstrated that arginine deprivation effectively inhibited the growth of retinoblastoma cells in vitro. This treatment caused an increase in the autophagic response. Additionally, prolonged arginine deprivation induced G2 cell cycle arrest and was accompanied by an increase in early apoptotic cells. Importantly, arginine depletion also induced the activation of GCN2 and the inhibition of mTOR signaling. We also discovered that the activation of SLC7A11 was regulated by GCN2 upon arginine deprivation. Knockdown of SLC7A11 rendered retinoblastoma cells partially resistant to arginine deprivation. Furthermore, we found that knockdown of GCN2 led to a decrease in the autophagic response in WERI-Rb-1 cells and arrested more cells in S phase, which was accompanied by fewer apoptotic cells. Moreover, knockdown of GCN2 induced the constant expression of ATF4 and the phosphorylation of 70S6K and 4E-BP1 regardless of arginine deprivation.ConclusionsCollectively, our findings suggest that the GCN2‒SLC7A11 axis regulates cell growth and survival upon arginine deprivation through coordinating autophagy, cell cycle arrest, and apoptosis in retinoblastoma cells. This work paves the way for the development of a novel treatment for retinoblastoma.

Somatic variant analysis of resected brain tissue in epilepsy surgery patients.

We studied the distribution of germline and somatic variants in epilepsy surgery patients with (suspected) malformations of cortical development (MCD) who underwent surgery between 2015 and 2020 at University Medical Center Utrecht (the Netherlands) and pooled our data with four previously published cohort studies. Tissue analysis yielded a pathogenic variant in 203 of 663 (31%) combined cases. In 126 of 379 (33%) focal cortical dysplasia (FCD) type II cases and 23 of 37 (62%) hemimegalencephaly cases, a pathogenic variant was identified, mostly involving the mTOR signaling pathway. Pathogenic variants in 10 focal epilepsy genes were found in 48 of 178 (27%) FCDI/mild MCD/mMCD with oligodendroglial hyperplasia and epilepsy cases; 36 of these (75%) were SLC35A2 variants. Six of 69 (9%) patients without a histopathological lesion had a pathogenic variant in SLC35A2 (n = 5) or DEPDC5 (n = 1). A germline variant in blood DNA was confirmed in all cases with a pathogenic variant in tissue, with a variant allele frequency (VAF) of ~50%. In seven of 114 patients (6%) with a somatic variant in tissue, mosaicism in blood was detected. More than half of pathogenic somatic variants had a VAF < 5%. Further analysis of the correlation between genetic variants and surgical outcomes will improve patient counseling and may guide postoperative treatment decisions.

Efficient, High-Quality Engineering of Therapeutic Extracellular Vesicles on an Integrated Nanoplatform.

Engineered extracellular vesicles (EVs) have been recognized as important therapeutics for gene and cell therapy. To achieve clinically desired therapy, technologies for EV engineering have high demands on the efficacy in producing EVs and their qualities, which, however, remain challenging to conventional routes due to their limited control on therapeutic payload delivery, EV secretion, and extracellular microenvironments. Here, we report a nanoplatform (denoted as PURE) that enables efficient electro-transfection while stimulating cells to produce high-quality EVs carrying functional RNAs. PURE further employs an ammonium removal zone to maintain the physiological conditions of the extracellular microenvironment and an EV uptake zone that efficiently (87.1%) captures EVs in situ with porous hydrogels. The platform achieved about a 12-fold higher yield of engineered EVs and a 146-fold abundance of desired therapeutics compared to those naturally secreted from cells. The PURE-engineered miR-130a-EVs were validated for effectively upregulating the mTOR signaling pathway in both in vitro and in vivo. Their therapeutic capability was then verified by enhancing the in vitro activation of primordial follicles. In vivo applications further highlighted the therapeutic effects of miR-130a-EVs in restoring ovary function in aged mice. The PURE platform represents a strategy for the clinical translation of EV-mediated therapy.

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.

Tetramethylpyrazine Analogue T-006 Protects Neuronal and Endothelial Cells Against Oxidative Stress via PI3K/AKT/mTOR and Nrf2 Signaling.

T-006, a novel neuroprotective derivative of tetramethylpyrazine (TMP), exhibits multifunctional neuroprotective properties. T-006 has been shown to improve neurological and behavioral functions in animal models of ischemic stroke and neurodegenerative diseases. The present study aims to further elucidate the mechanisms underlying the protective effects of T-006 against oxidative injuries induced by glutamate or hypoxia. Mouse hippocampal HT22 cells were used to evaluate the neuroprotective effects of T-006 against glutamate-induced injuries, while mouse brain endothelial bEnd.3 cells were used to evaluate the cerebrovascular protective effects of T-006 against oxygen-glucose deprivation followed by reperfusion (OGD/R)-induced injuries. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry were used to measure cell viability and oxidative stress. Western blot and immunofluorescence analyses of protein expression were used to study cell signaling pathways. T-006 exhibited significant protective effects in both oxidative injury models. In HT22 cells, T-006 reduced cell death and enhanced antioxidant capacity by upregulating mTOR and nuclear factor erythroid 2-related factor 2/Heme oxygenase-1 (Nrf2/HO-1) signaling. Similarly, in bEnd.3 cells, T-006 reduced oxidative injuries and preserved tight junction integrity through Nrf2/HO-1 upregulation. These effects were inhibited by LY294002, a Phosphoinositide 3-kinase (PI3K) inhibitor. T-006 may exert its neuroprotective and cerebrovascular protective effects via the regulation of PI3K/AKT-mediated pathways, which facilitate downstream mTOR and Nrf2 signaling, leading to improved cell survival and antioxidant defenses.

Branched-chain amino acid catabolism promotes ovarian cancer cell proliferation via phosphorylation of mTOR.

This study uncovers altered amino acid metabolism, specifically increased BCAA catabolism, at the interface of ovarian cancer cells and omental tissue in a coculture model of HGSOC secondary metastasis. Enhanced BCAA catabolism may promote cancer cell proliferation through mTOR signaling, presenting potential therapeutic value. These findings deepen our understanding of HGSOC pathogenesis and the metastatic tumor microenvironment, offering insights for developing new treatment strategies.

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.

Gene Expression Shifts in Emperor Penguin Adaptation to the Extreme Antarctic Environment.

Gene expression can accelerate ecological divergence by rapidly tweaking the response of an organism to novel environments, with more divergent environments exerting stronger selection and supposedly, requiring faster adaptive responses. Organisms adapted to extreme environments provide ideal systems to test this hypothesis, particularly when compared to related species with milder ecological niches. The Emperor penguin (Aptenodytes forsteri) is the only endothermic vertebrate breeding in the harsh Antarctic winter, in stark contrast with the less cold-adapted sister species, the King penguin (A. patagonicus). Assembling the first de novo transcriptomes and analysing multi-tissue (brain, kidney, liver, muscle, skin) RNA-Seq data from natural populations of both species, we quantified the shifts in tissue-enhanced genes, co-expression gene networks, and differentially expressed genes characterising Emperor penguin adaptation to the extreme Antarctic. Our analyses revealed the crucial role played by muscle and liver in temperature homeostasis, fasting, and whole-body energy metabolism (glucose/insulin regulation, lipid metabolism, fatty acid beta-oxidation, and blood coagulation). Repatterning at the regulatory level appears as more important in the brain of the Emperor penguin, showing the lowest signature of differential gene expression, but the largest co-expression gene network shift. Nevertheless, over-expressed genes related to mTOR signalling in the brain and the liver support their central role in cold and fasting responses. Besides contributing to understanding the genetics underlying complex traits, like body energy reservoir management, our results provide a first insight into the role of gene expression in adaptation to one of the most extreme environmental conditions endured by an endotherm.

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.

Synergistic Role of Amino Acids in Enhancing mTOR Activation Through Lysosome Positioning.

Lysosome positioning, or lysosome cellular distribution, is critical for lysosomal functions in response to both extracellular and intracellular cues. Amino acids, as essential nutrients, have been shown to promote lysosome movement toward the cell periphery. Peripheral lysosomes are involved in processes such as lysosomal exocytosis, cell migration, and metabolic signaling-functions that are particularly important for cancer cell motility and growth. However, the specific types of amino acids that regulate lysosome positioning, their underlying mechanisms, and their connection to amino acid-regulated metabolic signaling remain poorly understood. In this study, we developed a high-content imaging system for unbiased, quantitative analysis of lysosome positioning. We examined the 15 amino acids present in cell culture media and found that 10 promoted lysosome redistribution toward the cell periphery to varying extents, with aromatic amino acids showing the strongest effect. This redistribution was mediated by promoting outward transport through SLC38A9-BORC-kinesin 1/3 axis and simultaneously reducing inward transport via inhibiting the recruitment of Rab7 and JIP4 onto lysosomes. When examining the effects of amino acids on mTOR activation-a central regulator of cell metabolism-we found that the amino acids most strongly promoting lysosome dispersal, such as phenylalanine, did not activate mTOR on their own. However, combining phenylalanine with arginine, which activates mTOR without affecting lysosome positioning, synergistically enhanced mTOR activity. This synergy was lost when lysosomes failed to localize to the cell periphery, as observed in kinesin 1/3 knockout (KO) cells. Furthermore, breast cancer cells exhibited heightened sensitivity to phenylalanine-induced lysosome dispersal compared to noncancerous breast cells. Inhibition of LAT1, the amino acid transporter responsible for phenylalanine uptake, reduced peripheral lysosomes and impaired cancer cell migration and proliferation, highlighting the importance of lysosome positioning in these coordinated cellular activities. In summary, amino acid-regulated lysosome positioning and mTOR signaling depend on distinct sets of amino acids. Combining lysosome-dispersing amino acids with mTOR-activating amino acids synergistically enhances mTOR activation, which may be particularly relevant in cancer cells.