RESUMEN
The mTOR complex 1 (mTORC1) is an essential metabolic hub that coordinates cellular metabolism with the availability of nutrients, including amino acids. Sestrin2 has been identified as a cytosolic leucine sensor that transmits leucine status signals to mTORC1. In this study, we identify an E3 ubiquitin ligase RING finger protein 167 (RNF167) and a deubiquitinase STAMBPL1 that function in concert to control the polyubiquitination level of Sestrin2 in response to leucine availability. Ubiquitination of Sestrin2 promotes its interaction with GATOR2 and inhibits mTORC1 signaling. Bioinformatic analysis reveals decreased RNF167 expression and increased STAMBPL1 expression in gastric and colorectal tumors. Knockout of STAMBPL1 or correction of the heterozygous STAMBPL1 mutation in a human colon cancer cell line suppresses xenograft tumor growth. Lastly, a cell-permeable peptide that blocks the STAMBPL1-Sestrin2 interaction inhibits mTORC1 and provides a potential option for cancer therapy.
Asunto(s)
Neoplasias Colorrectales/enzimología , Péptido Hidrolasas/metabolismo , Neoplasias Gástricas/enzimología , Serina-Treonina Quinasas TOR/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Células CACO-2 , Proliferación Celular , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica , Células HCT116 , Células HEK293 , Humanos , Leucina/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Ratones Endogámicos BALB C , Ratones Desnudos , Mutación , Proteínas Nucleares/metabolismo , Péptido Hidrolasas/genética , Transducción de Señal , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Carga Tumoral , Ubiquitina-Proteína Ligasas/genética , UbiquitinaciónRESUMEN
The mTOR complex 1 (mTORC1) controls cell growth in response to amino acid levels1. Here we report SAR1B as a leucine sensor that regulates mTORC1 signalling in response to intracellular levels of leucine. Under conditions of leucine deficiency, SAR1B inhibits mTORC1 by physically targeting its activator GATOR2. In conditions of leucine sufficiency, SAR1B binds to leucine, undergoes a conformational change and dissociates from GATOR2, which results in mTORC1 activation. SAR1B-GATOR2-mTORC1 signalling is conserved in nematodes and has a role in the regulation of lifespan. Bioinformatic analysis reveals that SAR1B deficiency correlates with the development of lung cancer. The silencing of SAR1B and its paralogue SAR1A promotes mTORC1-dependent growth of lung tumours in mice. Our results reveal that SAR1B is a conserved leucine sensor that has a potential role in the development of lung cancer.
Asunto(s)
Leucina/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Proteínas de Unión al GTP Monoméricas/metabolismo , Transducción de Señal , Animales , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiología , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Secuencia Conservada , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Células HEK293 , Humanos , Leucina/deficiencia , Longevidad/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/agonistas , Ratones , Proteínas de Unión al GTP Monoméricas/química , Proteínas de Unión al GTP Monoméricas/deficiencia , Proteínas de Unión al GTP Monoméricas/genética , Complejos Multiproteicos/metabolismo , Proteínas Nucleares/metabolismo , Unión Proteica , Proteínas Supresoras de Tumor/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Ischemic stroke poses significant challenges in terms of mortality and disability rates globally. A key obstacle to the successful treatment of ischemic stroke lies in the limited efficacy of administering therapeutic agents. Leveraging the unique properties of nanoparticles for brain targeting and crossing the blood-brain barrier, researchers have engineered diverse nanoparticle-based drug delivery systems to improve the therapeutic outcomes of ischemic stroke. This review provides a concise overview of the pathophysiological mechanisms implicated in ischemic stroke, encompassing oxidative stress, glutamate excitotoxicity, neuroinflammation, and cell death, to elucidate potential targets for nanoparticle-based drug delivery systems. Furthermore, the review outlines the classification of nanoparticle-based drug delivery systems according to these distinct physiological processes. This categorization aids in identifying the attributes and commonalities of nanoparticles that target specific pathophysiological pathways in ischemic stroke, thereby facilitating the advancement of nanomedicine development. The review discusses the potential benefits and existing challenges associated with employing nanoparticles in the treatment of ischemic stroke, offering new perspectives on designing efficacious nanoparticles to enhance ischemic stroke treatment outcomes.
Asunto(s)
Barrera Hematoencefálica , Sistemas de Liberación de Medicamentos , Accidente Cerebrovascular Isquémico , Nanopartículas , Humanos , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Animales , Barrera Hematoencefálica/metabolismo , Sistemas de Liberación de Medicamentos/métodos , Nanopartículas/química , Estrés Oxidativo/efectos de los fármacos , Sistema de Administración de Fármacos con Nanopartículas/química , Isquemia Encefálica/tratamiento farmacológico , Nanomedicina/métodos , Encéfalo/metabolismo , Fármacos Neuroprotectores/uso terapéutico , Fármacos Neuroprotectores/químicaRESUMEN
AIM: The aim of this study is to identify potential serum biomarkers of Alzheimer's disease (AD) for early diagnosis and to evaluate these markers on a large cohort. METHODS: We performed two-dimensional difference gel electrophoresis to compare the serum of AD patients and normal controls. Western blot or enzyme-linked immunosorbent assay (ELISA) was used to identify the expression levels of proteins. RESULTS: In this study, a total of 13 differentially expressed proteins were identified. Among them, 2 proteins (inter-alpha-trypsin inhibitor heavy chain H4 [ITI-H4], Apolipoprotein A-IV) were validated by Western blot and 4 proteins (Cofilin 2, Tetranectin, Zinc-alpha-2-glycoprotein [AZGP1], Alpha-1-microglobulin/bikunin precursor [AMBP]) were validated by ELISA, respectively. Western blot results showed that the full size of the ITI-H4 protein was increased, while a fragment of ITI-H4 was decreased in AD patients. In contrast, 1 fragment of Apo A-IV was mainly found in control group and rare to be detected in AD patients. On the other hand, ELISA results showed that Cofilin 2, Tetranectin, AZGP1, and AMBP were significantly increased in AD patients, and Cofilin 2 is strongly correlated with the Mini-Mental State Examination scores of the AD patients. Serum Cofilin 2 was unchanged in Parkinson disease patients as compared to the control group, indicating a specific correlation of serum Cofilin 2 with AD. Moreover, Cofilin 2 was increased in both the serum and brain tissue in the APP/PS1 transgenic mice. CONCLUSION: Our study identified several potential serum biomarkers of AD, including: ITI-H4, ApoA-IV, Cofilin 2, Tetranectin, AZGP1, and AMBP. Cofilin 2 was upregulated in different AD animal models and might play important roles in AD pathology.
Asunto(s)
Enfermedad de Alzheimer , Enfermedad de Alzheimer/diagnóstico , Animales , Biomarcadores , Cofilina 2 , Humanos , Ratones , Proteómica/métodos , Electroforesis Bidimensional Diferencial en GelRESUMEN
The mechanistic target of rapamycin complex 1 (mTORC1) is an essential hub that integrates nutrient signals and coordinates metabolism to control cell growth. Amino acid signals are detected by sensor proteins and relayed to the GATOR2 and GATOR1 complexes to control mTORC1 activity. Here we perform genome-wide CRISPR/Cas9 screens, coupled with an assay for mTORC1 activity based on fluorescence-activated cell sorting analysis of pS6, to identify potential regulators of mTORC1-dependent amino acid sensing. We then focus on interleukin enhancer binding factor 3 (ILF3), one of the candidate genes from the screen. ILF3 tethers the GATOR complexes to lysosomes to control mTORC1. Adding a lysosome-targeting sequence to the GATOR2 component WDR24 bypasses the requirement for ILF3 to modulate amino-acid-dependent mTORC1 signalling. ILF3 plays an evolutionarily conserved role in human and mouse cells, and in worms to regulate the mTORC1 pathway, control autophagy activity and modulate the ageing process.
Asunto(s)
Aminoácidos , Serina-Treonina Quinasas TOR , Animales , Humanos , Ratones , Aminoácidos/metabolismo , Lisosomas/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/genética , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Complejos Multiproteicos/metabolismo , Proteínas del Factor Nuclear 90/genética , Proteínas del Factor Nuclear 90/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
The mechanistic target of rapamycin complex 1 (mTORC1) is a crucial regulator of cell growth. It senses nutrient signals and adjusts cellular metabolism accordingly. Deregulation of mTORC1 has been associated with metabolic diseases, cancer, and aging. Amino acid signals are transduced to mTORC1 through sensor proteins and two protein complexes named GATOR1 and GATOR2. In this study, we identify VWCE (von Willebrand factor C and EGF domains) as a negative regulator of amino acid-dependent mTORC1 signaling. Knockdown of VWCE promotes mTORC1 activity even in the absence of amino acids. VWCE interacts with the KICSTOR complex to facilitate the recruitment of GATOR1 to the lysosomes. Bioinformatic analysis reveals that expression of VWCE is reduced in prostate cancer. More importantly, overexpression of VWCE inhibits the development of prostate cancer. Therefore, VWCE may serve as a potential therapeutic target for the treatment of prostate cancers.
Asunto(s)
Aminoácidos , Neoplasias de la Próstata , Masculino , Humanos , Aminoácidos/metabolismo , Transducción de Señal , Diana Mecanicista del Complejo 1 de la Rapamicina/genética , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Lisosomas/metabolismoRESUMEN
N6-Methyldeoxyadenine (6mA) has been rediscovered as a DNA modification with potential biological function in metazoans. However, the physiological function and regulatory mechanisms regarding the establishment, maintenance and removal of 6mA in eukaryotes are still poorly understood. Here we show that genomic 6mA levels change in response to pathogenic infection in Caenorhabditis elegans (C. elegans). We further identify METL-9 as the methyltransferase that catalyzes DNA 6mA modifications upon pathogen infection. Deficiency of METL-9 impairs the induction of innate immune response genes and renders the animals more susceptible to pathogen infection. Interestingly, METL-9 functions through both 6mA-dependent and -independent mechanisms to transcriptionally regulate innate immunity. Our findings reveal that 6mA is a functional DNA modification in immunomodulation in C. elegans.
Asunto(s)
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Animales , Caenorhabditis elegans/genética , Metiltransferasas/genética , Metilación de ADN , ADN/genética , Inmunidad Innata , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismoRESUMEN
Breast cancer (BC) is one of the most common malignant tumors found in females. Previous studies have demonstrated that curcumin, which is a type of polyphenol compound extracted from Curcuma longa underground rhizome, is able to inhibit the survival of cancer cells. However, the functional role and mechanism of curcumin in BC are still unclear. The Cell Counting Kit-8 assay was performed to examine the effects of curcumin on cell viability in the BC cell lines MDA-MB-453 and MCF-7. The levels of lipid reactive oxygen species (ROS), malondialdehyde (MDA) production, and intracellular Fe2+ were determined to assess the effects of curcumin on cell ferroptosis. Western blot analysis was also carried out to detect the protein levels. Finally, the antitumorigenic effect of curcumin on BC was identified in a xenograft tumor model. In the present study, the results indicated that curcumin could dose-dependently suppress the viability of both MDA-MB-453 and MCF-7 cells. Further studies revealed that curcumin facilitated solute carrier family 1 member 5 (SLC1A5)-mediated ferroptosis in both MDA-MB-453 and MCF-7 cells by enhancing lipid ROS levels, lipid peroxidation end-product MDA accumulation, and intracellular Fe2+ levels. In vivo experiments demonstrated that curcumin could significantly hamper tumor growth. Collectively, the results demonstrated that curcumin exhibited antitumorigenic activity in BC by promoting SLC1A5-mediated ferroptosis, which suggests its use as a potential therapeutic agent for the treatment of BC.
Asunto(s)
Neoplasias de la MamaRESUMEN
A series of specific and potent fluorescent ligands were developed for labelling and visualizing Kv7.2/7.3 based molecular rotation restriction. Probes 21b and 24a were found to be safe and convenient tools to detect and visualize Kv7.2/7.3 in live cells and mouse brain tissue.