Glomerular Damage in Trichloroethylene-Sensitized Mice: Targeting Cathepsin L-Induced Hyperactive mTOR Signaling

Trichloroethylene (TCE) is a serious health hazard for workers with daily exposure, causing occupational medicamentosa-like dermatitis due to TCE (OMDT) and glomerular damage. Recent studies suggest that mTORC1 signaling is activated in various glomerular disorders; however, the role of mTORC1 signaling in TCE-induced glomerular damage remains to be explored. In the present study, 6 OMDT patients were enrolled and a TCE-sensitized mouse model was established to investigate molecular mechanisms underlying the glomerular damage associated with OMDT. Glomerular damage was assessed by levels of urine nephrin, H&E staining, and renal function test. Ultrastructural change of podocyte was investigated by transmission electron microscopy. The podocyte-related molecules including nephrin, α-actinin-4, and integrin β1 were visualized by immunofluorescence. The activation of mTORC1 signaling was confirmed by Western blot. Glomerular apoptosis was examined by the TUNEL test and Western blotting. Expression and location of cathepsin L (CTSL) were assessed by RT-PCR and immunofluorescence. Our results showed that TCE sensitization caused damage to glomerular structural integrity and also increased the activation of mTORC1 signaling, which was accompanied by podocyte loss, hypertrophy, and glomerular apoptosis. Importantly, we also found that over-expressed CTSL was mainly located in podocyte and CTSL inhibition could partially block the activation of mTORC1 signaling. Thus, our findings suggested a novel mechanism whereby hyperactive mTOR signaling contributes to TCE sensitization–induced and immune-mediated glomerular damage via CTSL activation.

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Ivermectin induces autophagy-mediated cell death through the AKT/mTOR signaling pathway in glioma cells

Bioscience Reports ◽

10.1042/bsr20192489 ◽

2019 ◽

Vol 39 (12) ◽

Cited By ~ 5

Author(s):

Jingjing Liu ◽

Hongsheng Liang ◽

Chen Chen ◽

Xiaoxing Wang ◽

Faling Qu ◽

...

Keyword(s):

Cell Death ◽

Molecular Mechanisms ◽

Anticancer Agent ◽

Glioma Cells ◽

Mtor Signaling ◽

Terminal Deoxynucleotidyl Transferase ◽

Transmission Electron ◽

Diphenyltetrazolium Bromide

Abstract Glioma is one of the most common types of primary brain tumors. Ivermectin (IVM), a broad-spectrum antiparasitic drug, has been identified as a novel anticancer agent due to its inhibitory effects on the proliferation of glioma cells in vitro and in vivo. However, the ability of IVM to induce autophagy and its role in glioma cell death remains unclear. The main objective of the present study was to explore autophagy induced by IVM in glioma U251 and C6 cells, and the deep underlying molecular mechanisms. In addition, we examined the effects of autophagy on apoptosis in glioma cells. In the present study, transmission electron microscopy (TEM), immunofluorescence, Western blot and immunohistochemistry were used to evaluate autophagy activated by IVM. Cell viability was measured by 3-(4,5-dimethylthiazol2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and colony formation assay. The apoptosis rate was detected by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Meanwhile, autophagy inhibition was achieved by using chloroquine (CQ). U251-derived xenografts were established for examination of IVM-induced autophagy on glioma in vivo. Taken together, the results of the present study showed that autophagy induced by IVM has a protective effect on cell apoptosis in vitro and in vivo. Mechanistically, IVM induced autophagy through AKT/mTOR signaling and induced energy impairment. Our findings show that IVM is a promising anticancer agent and may be a potential effective treatment for glioma cancers.

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mTOR Signaling Pathway Regulates Sperm Quality in Older Men

Cells ◽

10.3390/cells8060629 ◽

2019 ◽

Vol 8 (6) ◽

pp. 629 ◽

Cited By ~ 3

Author(s):

Silva ◽

Cabral ◽

Correia ◽

Carvalho ◽

Sousa ◽

...

Keyword(s):

Signaling Pathway ◽

Molecular Mechanisms ◽

Sperm Quality ◽

Older Men ◽

Mtor Signaling ◽

Paternal Age ◽

Signaling Proteins ◽

Mtor Signaling Pathway ◽

Mtorc1 Signaling ◽

The Impact

: Understanding how age affects fertility becomes increasingly relevant as couples delay childbearing toward later stages of their lives. While the influence of maternal age on fertility is well established, the impact of paternal age is poorly characterized. Thus, this study aimed to understand the molecular mechanisms responsible for age-dependent decline in spermatozoa quality. To attain it, we evaluated the impact of male age on the activity of signaling proteins in two distinct spermatozoa populations: total spermatozoa fraction and highly motile/viable fraction. In older men, we observed an inhibition of the mechanistic target of rapamycin complex 1 (mTORC1) in the highly viable spermatozoa population. On the contrary, when considering the entire spermatozoa population (including defective/immotile/apoptotic cells) our findings support an active mTORC1 signaling pathway in older men. Additionally, total spermatozoa fractions of older men presented increased levels of apoptotic/stress markers (e.g., cellular tumor antigen p53-TP53) and mitogen-activated protein kinases (MAPKs) activity. Moreover, we established that the levels of most signaling proteins analyzed were consistently and significantly altered in men more than 27 years of age. This study was the first to associate the mTOR signaling pathway with the age impact on spermatozoa quality. Additionally, we constructed a network of the sperm proteins associated with male aging, identifying TP53 as a central player in spermatozoa aging.

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Targeting the mTOR Signaling Pathway Utilizing Nanoparticles: A Critical Overview

Cancers ◽

10.3390/cancers11010082 ◽

2019 ◽

Vol 11 (1) ◽

pp. 82 ◽

Cited By ~ 18

Author(s):

Mariia Lunova ◽

Barbora Smolková ◽

Anna Lynnyk ◽

Mariia Uzhytchak ◽

Milan Jirsa ◽

...

Keyword(s):

Structural Changes ◽

Molecular Mechanisms ◽

Therapeutic Option ◽

Mammalian Target Of Rapamycin ◽

Mtor Signaling ◽

Therapeutic Effects ◽

Mtorc1 Signaling ◽

Challenges And Opportunities ◽

Signaling Axis ◽

Mtor Modulation

Proteins of the mammalian target of rapamycin (mTOR) signaling axis are overexpressed or mutated in cancers. However, clinical inhibition of mTOR signaling as a therapeutic strategy in oncology shows rather limited progress. Nanoparticle-based mTOR targeted therapy proposes an attractive therapeutic option for various types of cancers. Along with the progress in the biomedical applications of nanoparticles, we start to realize the challenges and opportunities that lie ahead. Here, we critically analyze the current literature on the modulation of mTOR activity by nanoparticles, demonstrate the complexity of cellular responses to functionalized nanoparticles, and underline challenges lying in the identification of the molecular mechanisms of mTOR signaling affected by nanoparticles. We propose the idea that subcytotoxic doses of nanoparticles could be relevant for the induction of subcellular structural changes with possible involvement of mTORC1 signaling. The evaluation of the mechanisms and therapeutic effects of nanoparticle-based mTOR modulation will provide fundamental knowledge which could help in developing safe and efficient nano-therapeutics.

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Integrative cBioPortal Analysis Revealed Molecular Mechanisms That Regulate EGFR-PI3K-AKT-mTOR Pathway in Diffuse Gliomas of the Brain

Cancers ◽

10.3390/cancers13133247 ◽

2021 ◽

Vol 13 (13) ◽

pp. 3247

Author(s):

Petar Brlek ◽

Anja Kafka ◽

Anja Bukovac ◽

Nives Pećina-Šlaus

Keyword(s):

Large Scale ◽

Molecular Mechanisms ◽

In Silico Analysis ◽

Total Sample ◽

Mtor Signaling ◽

Biological Behavior ◽

Mrna Transcription ◽

Diffuse Gliomas ◽

New Treatment ◽

Using Data

Diffuse gliomas are a heterogeneous group of tumors with aggressive biological behavior and a lack of effective treatment methods. Despite new molecular findings, the differences between pathohistological types still require better understanding. In this in silico analysis, we investigated AKT1, AKT2, AKT3, CHUK, GSK3β, EGFR, PTEN, and PIK3AP1 as participants of EGFR-PI3K-AKT-mTOR signaling using data from the publicly available cBioPortal platform. Integrative large-scale analyses investigated changes in copy number aberrations (CNA), methylation, mRNA transcription and protein expression within 751 samples of diffuse astrocytomas, anaplastic astrocytomas and glioblastomas. The study showed a significant percentage of CNA in PTEN (76%), PIK3AP1 and CHUK (75% each), EGFR (74%), AKT2 (39%), AKT1 (32%), AKT3 (19%) and GSK3β (18%) in the total sample. Comprehensive statistical analyses show how genomics and epigenomics affect the expression of examined genes differently across various pathohistological types and grades, suggesting that genes AKT3, CHUK and PTEN behave like tumor suppressors, while AKT1, AKT2, EGFR, and PIK3AP1 show oncogenic behavior and are involved in enhanced activity of the EGFR-PI3K-AKT-mTOR signaling pathway. Our findings contribute to the knowledge of the molecular differences between pathohistological types and ultimately offer the possibility of new treatment targets and personalized therapies in patients with diffuse gliomas.

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CIB2 regulates mTORC1 signaling and is essential for autophagy and visual function

Nature Communications ◽

10.1038/s41467-021-24056-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Saumil Sethna ◽

Patrick A. Scott ◽

Arnaud P. J. Giese ◽

Todd Duncan ◽

Xiaoying Jian ◽

...

Keyword(s):

Visual Function ◽

Molecular Mechanisms ◽

Neurodegenerative Disorder ◽

Pigment Epithelium ◽

Retinal Pigment ◽

Negative Regulator ◽

Age Related Macular Degeneration ◽

Age Related ◽

Mtorc1 Signaling ◽

Marked Accumulation

AbstractAge-related macular degeneration (AMD) is a multifactorial neurodegenerative disorder. Although molecular mechanisms remain elusive, deficits in autophagy have been associated with AMD. Here we show that deficiency of calcium and integrin binding protein 2 (CIB2) in mice, leads to age-related pathologies, including sub-retinal pigment epithelium (RPE) deposits, marked accumulation of drusen markers APOE, C3, Aβ, and esterified cholesterol, and impaired visual function, which can be rescued using exogenous retinoids. Cib2 mutant mice exhibit reduced lysosomal capacity and autophagic clearance, and increased mTORC1 signaling—a negative regulator of autophagy. We observe concordant molecular deficits in dry-AMD RPE/choroid post-mortem human tissues. Mechanistically, CIB2 negatively regulates mTORC1 by preferentially binding to ‘nucleotide empty’ or inactive GDP-loaded Rheb. Upregulated mTORC1 signaling has been implicated in lymphangioleiomyomatosis (LAM) cancer. Over-expressing CIB2 in LAM patient-derived fibroblasts downregulates hyperactive mTORC1 signaling. Thus, our findings have significant implications for treatment of AMD and other mTORC1 hyperactivity-associated disorders.

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Abstract 041: mTORC1 is Required for Leptin-induced Sympathetic Activation to the Kidney but Not Brown Adipose Tissue

Hypertension ◽

10.1161/hyp.68.suppl_1.041 ◽

2016 ◽

Vol 68 (suppl_1) ◽

Author(s):

Balyssa B Bell ◽

Donald A Morgan ◽

Kamal Rahmouni

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Molecular Mechanisms ◽

Leptin Receptor ◽

Critical Role ◽

Conditional Knockout ◽

Sympathetic Activation ◽

Long Term Effects ◽

Brown Adipose ◽

Mtorc1 Signaling

The adipocyte-derived hormone leptin plays a critical role in the regulation of energy homeostasis through its action in the brain to decrease food intake and promote energy expenditure by increasing sympathetic nerve activity (SNA) to the thermogenic brown adipose tissue (BAT). Leptin also increases SNA to cardiovascular organs including the kidney and raises arterial pressure. However, it is unclear whether leptin controls regional SNA via conserved or distinct molecular mechanisms. Multiple intracellular pathways have been associated with leptin signaling including the mechanistic target of rapamycin complex 1 (mTORC1), which has been proposed as a critical determinant of leptin action. Here, we assessed the contribution of mTORC1 signaling to leptin-evoked regional sympathetic activation. Simultaneous multifiber recording of renal and BAT SNA in anesthetized C57BL/6J mice showed that intracerebroventricular (ICV) administration of leptin (2μg, n=5) increased both renal (170±34%) and BAT (208±37%) SNA. Interestingly, ICV pre-treatment with the mTORC1 inhibitor (rapamycin, 5ng, n=6) abolished the leptin-induced increase in renal (10±6%, P<0.05 vs controls) but not BAT (226±31%) SNA. Next, we used conditional knockout mice that lack the critical mTORC1 subunit, Raptor, specifically in leptin receptor (LRb)-expressing cells (LRb Cre /Raptor fl/fl ) to determine the long-term effects of disrupting mTORC1 signaling on leptin-evoked increase in regional SNA. We confirmed the inability of leptin to activate mTORC1 signaling in LRb-expressing cells of LRb Cre /Raptor fl/fl mice relative to controls using immunohistochemical staining of phosphorylated ribosomal S6, a downstream target of mTORC1. We observed a significant increase in renal SNA in response to ICV leptin in control mice (127±16%, n=9), but not in LRb Cre /Raptor fl/fl mice (-4±15%, n=9, P<0.05 vs controls). Conversely, ICV leptin-induced increase in BAT SNA was not different in LRb Cre /Raptor fl/fl mice (109±27%, n=5) vs. littermate controls (173±52%, n=4). Our data suggest a critical role for mTORC1 signaling in selectively mediating the cardiovascular sympathetic but not the thermogenic actions of leptin, with important implications for obesity-associated hypertension.

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AMP-Activated Protein Kinase as a Key Trigger for the Disuse-Induced Skeletal Muscle Remodeling

International Journal of Molecular Sciences ◽

10.3390/ijms19113558 ◽

2018 ◽

Vol 19 (11) ◽

pp. 3558 ◽

Cited By ~ 13

Author(s):

Natalia Vilchinskaya ◽

Igor Krivoi ◽

Boris Shenkman

Keyword(s):

Skeletal Muscle ◽

Protein Kinase ◽

Histone Deacetylases ◽

Molecular Mechanisms ◽

Weight Bearing ◽

Mammalian Target Of Rapamycin ◽

Adenosine Monophosphate ◽

Chain Gene ◽

Mtorc1 Signaling ◽

The Impact

Molecular mechanisms that trigger disuse-induced postural muscle atrophy as well as myosin phenotype transformations are poorly studied. This review will summarize the impact of 5′ adenosine monophosphate -activated protein kinase (AMPK) activity on mammalian target of rapamycin complex 1 (mTORC1)-signaling, nuclear-cytoplasmic traffic of class IIa histone deacetylases (HDAC), and myosin heavy chain gene expression in mammalian postural muscles (mainly, soleus muscle) under disuse conditions, i.e., withdrawal of weight-bearing from ankle extensors. Based on the current literature and the authors’ own experimental data, the present review points out that AMPK plays a key role in the regulation of signaling pathways that determine metabolic, structural, and functional alternations in skeletal muscle fibers under disuse.

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Inversely proportional myelin growth due to altered Pmp22 gene dosage identifies PI3K/Akt/mTOR signaling as a novel therapeutic target in HNPP

10.1101/2021.11.08.467756 ◽

2021 ◽

Author(s):

Doris Krauter ◽

David Ewers ◽

Timon J Hartmann ◽

Stefan Volkmann ◽

Theresa Kungl ◽

...

Keyword(s):

Growth Regulation ◽

Molecular Mechanisms ◽

Motor Behavior ◽

Gene Dosage ◽

Mtor Signaling ◽

Hereditary Neuropathy ◽

Gene Encoding ◽

Phosphatase And Tensin Homolog ◽

Charcot Marie Tooth Disease ◽

Tensin Homolog

Duplication of the gene encoding the myelin protein PMP22 causes the hereditary neuropathy Charcot-Marie-Tooth disease 1A (CMT1A), characterized by hypomyelination of medium to large peripheral axons. Conversely, haplo-insufficiency of PMP22 leads to focal myelin overgrowth in hereditary neuropathy with liability to pressure palsies (HNPP). However, the molecular mechanisms of myelin growth regulation by PMP22 remain obscure. Here, we found that the major inhibitor of the myelin growth signaling pathway PI3K/Akt/mTOR, phosphatase and tensin homolog (PTEN) is increased in abundance in CMT1A and decreased in HNPP rodent models. Indeed, treatment of DRG co-cultures from HNPP mice with PI3K/Akt/mTOR pathway inhibitors reduced focal hypermyelination and, importantly, treatment of HNPP mice with the mTOR inhibitor Rapamycin improved motor behavior, increased compound muscle amplitudes (CMAP) and reduced tomacula formation in the peripheral nerve. In Pmp22tg CMT1A mice, we uncovered that the differentiation defect of Schwann cells is independent from PI3K/Akt/mTOR activity, rendering the pathway insufficient as a therapy target on its own. Thus, while CMT1A pathogenesis is governed by dys-differentiation uncoupled from PI3K/Akt/mTOR signaling, targeting the pathway provides novel proof-of-principle for a therapeutic approach to HNPP.

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Inhibition of 11β-HSD1 Ameliorates Cognition and Molecular Detrimental Changes after Chronic Mild Stress in SAMP8 Mice

Pharmaceuticals ◽

10.3390/ph14101040 ◽

2021 ◽

Vol 14 (10) ◽

pp. 1040

Author(s):

Dolors Puigoriol-Illamola ◽

Júlia Companys-Alemany ◽

Kris McGuire ◽

Natalie Z. M. Homer ◽

Rosana Leiva ◽

...

Keyword(s):

Stress Responses ◽

Healthy Aging ◽

Molecular Mechanisms ◽

Chronic Mild Stress ◽

Mild Stress ◽

Cognitive Improvement ◽

Age Related ◽

Mtorc1 Signaling ◽

Cognitive Disturbances ◽

Samp8 Mice

Impaired glucocorticoid (GC) signaling is a significant factor in aging, stress, and neurodegenerative diseases such as Alzheimer’s disease. Therefore, the study of GC-mediated stress responses to chronic moderately stressful situations, which occur in daily life, is of huge interest for the design of pharmacological strategies toward the prevention of neurodegeneration. To address this issue, SAMP8 mice were exposed to the chronic mild stress (CMS) paradigm for 4 weeks and treated with RL-118, an 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor. The inhibition of this enzyme is linked with a reduction in GC levels and cognitive improvement, while CMS exposure has been associated with reduced cognitive performance. The aim of this project was to assess whether RL-118 treatment could reverse the deleterious effects of CMS on cognition and behavioral abilities and to evaluate the molecular mechanisms that compromise healthy aging in SAMP8 mice. First, we confirmed the target engagement between RL-118 and 11β-HSD1. Additionally, we showed that DNA methylation, hydroxymethylation, and histone phosphorylation were decreased by CMS induction, and increased by RL-118 treatment. In addition, CMS exposure caused the accumulation of reactive oxygen species (ROS)-induced damage and increased pro-oxidant enzymes—as well as pro-inflammatory mediators—through the NF-κB pathway and astrogliosis markers, such as GFAP. Of note, these modifications were reversed by 11β-HSD1 inhibition. Remarkably, although CMS altered mTORC1 signaling, autophagy was increased in the SAMP8 RL-118-treated mice. We also showed an increase in amyloidogenic processes and a decrease in synaptic plasticity and neuronal remodeling markers in mice under CMS, which were consequently modified by RL-118 treatment. In conclusion, 11β-HSD1 inhibition through RL-118 ameliorated the detrimental effects induced by CMS, including epigenetic and cognitive disturbances, indicating that GC-excess attenuation shows potential as a therapeutic strategy for age-related cognitive decline and AD.

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