RESUMO
Opposing dose-dependent effects of curcumin (Cur) have been documented in Retinal Pigment Epithelium (RPE); therefore, to shed the light on the mechanisms of action is crucial for ophthalmic applications. On this basis we explored new insights about the dose-dependent mechanisms triggered by Cur in human retinal pigment epithelial cells (ARPE-19). Three concentrations (0.01 mM; 0.05 mM; 0.1 mM) of Cur were tested, followed by morphological, molecular, and functional analysis of the cells. Cur 0.01 mM promotes a significant increase in cell proliferation, not affecting cell cycle progression and apoptosis; by contrast, Cur 0.05 mM and 0.1 mM block cellular proliferation and trigger S-phase cell cycle arrest without inducing apoptosis. The observation of neuronal-like morphological changes in Cur 0.05 mM and 0.1 mM were not associated with neuronal differentiation, as observed by the quantification of Neurofilament-200 and by the analysis of voltage-dependent currents by patch clamp. Evaluation of autophagic markers LC3BII and p62 revealed significant modulations, suggesting an important activation of autophagy in ARPE-19 cells treated with Cur 0.05 mM and Cur 0.1 mM; conversely, Cur 0.01 mM did not affect autophagy. Altogether, our findings show new dose-dependent mechanisms of action of Cur that suggest a wide therapeutic application in ocular diseases with different pathogenesis (i.e., proliferative vitreoretinopathy or Age-Related Macular Degeneration).
Assuntos
Curcumina , Humanos , Curcumina/farmacologia , Curcumina/metabolismo , Epitélio Pigmentado da Retina/metabolismo , Autofagia , Apoptose , Proliferação de CélulasRESUMO
Autophagy is a cellular process activated in response to various stresses such as starvation, hypoxia, and oxidative stress. Autophagy was reported to modulate the inflammatory pathways. However, whether autophagy is involved in regulation of palmitate-induced inflammation of skeletal muscle C2C12 cells is still unknown. The present study aimed to investigate the autophagic pathway in C2C12 cells treated with 0.5â¯mM palmitate. The results showed that the protein levels of LC3BII and P62 were increased in C2C12 cells after 12â¯h palmitate treatment. Besides, inhibition of autophagy by chloroquine or 3-methyladenin and its activation by rapamycin were associated with elevated mRNA and protein levels of IL-6 and TNF-α inflammatory cytokines in C2C12 cells. To study the mechanism by which autophagy impairment leads to activation of inflammatory responses, reactive oxygen species (ROS) levels in palmitate-treated cells were measured. The results showed that while palmitate stimulates ROS production, pretreatment of the cells with N-acetyl cysteine (NAC), a ROS scavenger, reduced inflammatory responses and also improved LC3-BII and P62 protein in the C2C12 cells exposed to palmitate. These findings suggest that palmitate-induced defect of autophagic flux leads to elevated inflammatory cytokine expression in the skeletal muscle cells by regulating the oxidative stress process.
Assuntos
Autofagia/efeitos dos fármacos , Citocinas/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Músculo Esquelético/metabolismo , Palmitatos/farmacologia , Acetilcisteína/farmacologia , Adenina/análogos & derivados , Adenina/farmacologia , Animais , Autofagia/genética , Linhagem Celular , Cloroquina/farmacologia , Sequestradores de Radicais Livres/farmacologia , Inflamação/metabolismo , Interleucina-6/metabolismo , Camundongos , Músculo Esquelético/efeitos dos fármacos , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Proteína Sequestossoma-1/metabolismo , Sirolimo/farmacologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Targeting residual self-renewing, chemoresistant cancerous cells may represent the key to overcoming therapy resistance. The entry of these quiescent cells into an activated state is associated with high metabolic demand and autophagic flux. Therefore, modulating the autophagy pathway in aggressive carcinomas may be beneficial as a therapeutic modality. In this study, we evaluated the anti-tumor activities of 4-acetylantroquinonol B (4-AAQB) in chemoresistant ovarian cancer cells, particularly its ability to modulate autophagy through autophagy-related genes (Atg). Atg-5 was overexpressed in invasive ovarian cancer cell lines and tissue (OR: 5.133; P=0.027) and depleting Atg-5 in ES-2 cell lines significantly induced apoptosis. 4-AAQB effectively suppressed viability of various subtypes of ovarian cancer. Cells with higher cisplatin-resistance were more responsive to 4-AAQB. For the first time, we demonstrate that 4-AAQB significantly suppress Atg-5 and Atg-7 expression with decreased autophagic flux in ovarian cancer cells via inhibition of the PI3K/Akt/mTOR/p70S6K signaling pathway. Similar to Atg-5 silencing, 4-AAQB-induced autophagy inhibition significantly enhanced cell death in vitro. These results are comparable to those of hydroxychloroquine (HCQ). In addition, 4-AAQB/cisplatin synergistically induced apoptosis in ovarian cancer cells. In vivo, 4-AAQB/cisplatin also significantly induced apoptosis and autophagy in an ES-2 mouse xenografts model. This is the first report demonstrating the efficacy of 4-AAQB alone or in combination with cisplatin on the suppression of ovarian cancer via Atg-5-dependent autophagy. We believe these findings will be beneficial in the development of a novel anti-ovarian cancer therapeutic strategy.
Assuntos
4-Butirolactona/análogos & derivados , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Autofagia/efeitos dos fármacos , Cisplatino/farmacologia , Cicloexanonas/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias Epiteliais e Glandulares/tratamento farmacológico , Neoplasias Ovarianas/tratamento farmacológico , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Serina-Treonina Quinases TOR/metabolismo , 4-Butirolactona/farmacologia , Animais , Apoptose/efeitos dos fármacos , Proteína 5 Relacionada à Autofagia/genética , Proteína 5 Relacionada à Autofagia/metabolismo , Carcinoma Epitelial do Ovário , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Feminino , Humanos , Camundongos Endogâmicos NOD , Camundongos SCID , Neoplasias Epiteliais e Glandulares/enzimologia , Neoplasias Epiteliais e Glandulares/genética , Neoplasias Epiteliais e Glandulares/patologia , Neoplasias Ovarianas/enzimologia , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Interferência de RNA , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo , Transfecção , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Autophagy is a fundamental cellular degradation process which is essential for cell homeostasis, and dysfunctional autophagy has been associated with a variety of human diseases, such as cancer. Several autophagy chemical modulators have been applied in a number of preclinical or clinical trials against these autophagy related diseases, especially cancer. Small molecule vacuolin-1 potently and reversibly inhibits both endosomal-lysosomal trafficking and autophagosome-lysosome fusion, yet the molecular mechanisms underlying vacuolin-1 mediated autophagy inhibition remain unknown. Here, we first performed the virtual drug screening and identified 14 vacuolin-1 analogues as autophagy inhibitors. Based on these virtual screening results, we further designed and synthesized 17 vacuolin-1 analogues, and found that 13 of them are autophagy inhibitors and a couple of them are as potent as vacuolin-1. In summary, these studies expanded the pool of useful autophagy inhibitors and reveal the structural-activity relationship of vacuolin-1 analogues, which is useful for future development of vacuolin-1 analogues with high potency and for identification of the molecular targets of vacuolin-1.
Assuntos
Autofagia/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Compostos Heterocíclicos de 4 ou mais Anéis/química , Endossomos/química , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Humanos , Lisossomos/químicaRESUMO
Ammonia (NH3) is an irritating gas and atmospheric pollutant that endangers the health of humans and animals by stimulating respiratory tract's mucosa and causing liver damage. However, physiological role of ammonia gas in hepatotoxicity remains unclear. To investigate the hepatotoxic effects of inhaled ammonia gas, experiments were conducted using mouse model exposed to 100 ppm of ammonia gas for 21 days. The exposed mice exhibited signs of depression, emaciation, and reduced growth. This study revealed that inhalation of ammonia led to significant decrease in water (P < 0.0001) and food intake (P < 0.05), resulting in slower growth. Histopathological analysis showed that ammonia stress alters the microstructure of the liver by enlarging the gap between hepatic lobule and fibrosis. Moreover, ammonia-induced stress significantly reduces the expression of the anti-apoptotic protein BCl-2 (P < 0.001), while elevates the mRNA expression of the pro-apoptotic gene Bax (P < 0.001). Furthermore, ammonia inhalation significantly increases the protein expression of LC-3bII (P < 0.05) and the mRNA expression of autophagy-related gene 5 (ATG5) (P < 0.05) and p62 (P < 0.05) while remarkably decreases the mRNA expression of mammalian target of rapamycin (m-TOR) (P < 0.05). In conclusion, this study demonstrates that inhalation of ammonia gas causes liver damage and suggests autophagy happening via m-TOR/p62/LC-3bII and pro-apoptosis effect mediated by Bax/BCl-2 in the liver damage caused by ammonia inhalation. Our study provides a new perspective on ammonia-induced hepatotoxicity.
Assuntos
Amônia , Doença Hepática Induzida por Substâncias e Drogas , Humanos , Camundongos , Animais , Proteína X Associada a bcl-2 , Amônia/toxicidade , Serina-Treonina Quinases TOR/metabolismo , Serina-Treonina Quinases TOR/farmacologia , Apoptose , Hepatócitos , RNA Mensageiro , Doença Hepática Induzida por Substâncias e Drogas/patologia , Autofagia , Mamíferos/metabolismo , Proteína 5 Relacionada à Autofagia/farmacologiaRESUMO
The word mad has historically been associated with the psyche, emotions, and abnormal behavior. Dementia is a common symptom among psychiatric disorders or mad (schizophrenia, depression, bipolar disorder) patients. Autophagy/mitophagy is a protective mechanism used by cells to get rid of dysfunctional cellular organelles or mitochondria. Autophagosome/mitophagosome abundance in autophagy depends on microtubule-associated protein light chain 3B (LC3B-II) and autophagy-triggering gene (ATG) which functions as an autophagic biomarker for phagophore production and quick mRNA disintegration. Defects in either LC3B-II or the ATG lead to dysregulated mitophagy-and-autophagy-linked dementia (MAD). The impaired MAD is closely associated with schizophrenia, depression, and bipolar disorder. The pathomechanism of psychosis is not entirely known, which is the severe limitation of today's antipsychotic drugs. However, the reviewed circuit identifies new insights that may be especially helpful in targeting biomarkers of dementia. Neuro-theranostics can also be achieved by manufacturing either bioengineered bacterial and mammalian cells or nanocarriers (liposomes, polymers, and nanogels) loaded with both imaging and therapeutic materials. The nanocarriers must cross the BBB and should release both diagnostic agents and therapeutic agents in a controlled manner to prove their effectiveness against psychiatric disorders. In this review, we highlighted the potential of microRNAs (miRs) as neuro-theranostics in the treatment of dementia by targeting autophagic biomarkers LC3B-II and ATG. Focus was also placed on the potential for neuro-theranostic nanocells/nanocarriers to traverse the BBB and induce action against psychiatric disorders. The neuro-theranostic approach can provide targeted treatment for mental disorders by creating theranostic nanocarriers.
Assuntos
Demência , Mitofagia , Animais , Humanos , Medicina de Precisão , Autofagia , Proteínas Associadas aos Microtúbulos/metabolismo , Biomarcadores , Mamíferos/metabolismoRESUMO
Cells can communicate through the extracellular vesicles (EVs) they secrete. Pathogen associated molecular patterns (PAMPs), alter the biophysical and communicative properties of EVs released from cells, but the functional consequences of these changes are unknown. Characterization of keratinocyte-derived EVs after poly(I:C) treatment (poly(I:C)-EVs) showed slight differences in levels of EV markers TSG101 and Alix, a loss of CD63 and were positive for autophagosome marker LC3b-II and the cytokine IL36γ compared to EVs from unstimulated keratinocytes (control-EVs). Flagellin treatment (flagellin-EVs) led to an EV marker profile like control-EVs but lacked LC3b-II. Flagellin-EVs also lacked IL-36γ despite nearly identical intracellular levels. While poly(I:C) treatment led to the clear emergence of a > 200 nm diameter EV sub-population, these were not found in flagellin-EVs. EV associated IL-36γ colocalized with LC3b-II in density gradient analysis, equilibrating to 1.10 g/mL, indicating a common EV species. Poly(I:C), but not flagellin, induced intracellular vesicles positive for IL-36γ, LC3b-II, Alix and TSG101, consistent with fusion of autophagosomes and multivesicular bodies. Simultaneous rapamycin and flagellin treatment induced similar intracellular vesicles but was insufficient for the release of IL-36γ+/LC3b-II+ EVs. Finally, a qRT-PCR array screen showed eight cytokine/chemokine transcripts were altered (p < 0.05) in monocyte-derived Langerhans cells (LCs) when stimulated with poly(I:C)-EVs while three were altered when LCs were stimulated with flagellin-EVs compared to control-EVs. After independent confirmation, poly(I:C)-EVs upregulated BMP6 (p = 0.035) and flagellin-EVs upregulated CXCL8 (p = 0.005), VEGFA (p = 0.018) and PTGS2 (p = 0.020) compared to control-EVs. We conclude that exogenous signals derived from pathogens can alter keratinocyte-mediated modulation of the local immune responses by inducing changes in the types of EVs secreted and responses in antigen presenting cells.
Assuntos
Células Apresentadoras de Antígenos/metabolismo , Vesículas Extracelulares/metabolismo , Queratinócitos/metabolismo , Poli I-C/farmacologia , Receptores Toll-Like/agonistas , Ácido Ascórbico , Células Cultivadas , Colecalciferol , Desidroepiandrosterona/análogos & derivados , Ácidos Nicotínicos , Extratos Vegetais , Receptores Toll-Like/metabolismoRESUMO
BACKGROUND/AIM: We previously identified a panel of five miRNAs (including miR-139) associated with biochemical recurrence and metastasis in prostate cancer patients. MATERIALS AND METHODS: We examined miR-139 transfected PC3, DU145 and LNCaP cells by morphology as well as by cell-based assays, confocal microscopy and immunoblotting. RESULTS: We found that treatment of prostate cancer cells with miR-139 resulted in phenotypic changes characteristic of autophagic cells. MiR-139 increased the autophagy-related conversion of the microtubule-associated protein light chain 3 (LC3-I to LC3-II) that was specifically inhibited by the miR-139 antagomir. The upregulation of LC3 II was further confirmed by confocal microscopy. miR-139 regulated activation of both mTOR and Beclin1 the two important autophagy-related molecules. We found that upon miR-139 treatment, the cargo adaptor protein p62 which is degraded during autophagy, accumulates. CONCLUSION: These results suggest that miR-139 is inducing autophagic flux blockade leading to apoptosis in prostate cancer cells through the mTOR and Beclin-1 proteins.
Assuntos
Autofagia/genética , Proteína Beclina-1/metabolismo , MicroRNAs/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Apoptose/genética , Linhagem Celular Tumoral , Forma Celular/genética , Regulação para Baixo/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Sistema de Sinalização das MAP Quinases , Masculino , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Regulação para Cima/genéticaRESUMO
The role of vitamin D in the regulation of lung immune defense and inflammatory response has attracted more and more attention. Vitamin D deficiency is closely related to respiratory tract infections. However, few studies have elucidated the mechanism of vitamin D deficiency on host pulmonary resistance to Aspergillus fumigatus (A. fumigatus). In this paper, the role of autophagy and Treg regulation in the treatment of rat models of A. fumigatus infection with vitamin D was investigated. We intratracheally injected the A. fumigatus spores into Mice fed with sufficient vitamin D (VitD+) or deficient diets (VitD-). Mortality, fungal load and weight changes were evaluated. The conidia of lung tissue were isolated for analysis of viability. Alveolar macrophages (AMs) were stimulated with a viable A. fumigatus conidia for determining the formation of lysosomes in vitro. The autophagy-related proteins dectin-1, ROS and LC3BII expression in AMs were measured. Fluorescence and Western blot were performed to evaluate the autophagic flux and Treg cells were detected by flow cytometry. After inoculation with A. fumigatus, the vitamin D deficient mice exhibited a higher rate of death, more fungal growth, and more weight loss than its sufficient peers. The viability of A. fumigatus conidia in VitD+ mice was significantly lower than that in VitD- mice. In the case of A. fumigatus infection, vitamin D delays the formation of lysosomes against A. fumigatus through autophagy. The autophagy flow measurement experiment also found that the vitamin D group lowered autophagy levels in cells and a small number of Treg cells. In conclusion, Vitamin D deficiency can lead to impaired lung defense in mice, which may be associated with the formation of excessive autophagy-induced lysosomes and increased counts of Treg cells.
RESUMO
BACKGROUND: Autophagy exists widely in various physiological and pathological conditions. Lots of investigations have verified that the autophagic activity is always related to the occurrence and the development of cancer. Endometriosis (EMs) is a disease that endometrium-like tissues abnormally grow outside the uterus and also considered to possess the characters of tumor because of its malignant biological behavior. INTRODUCTION: Recently, several studies have already revealed that autophagy may play a potential role in proliferative-phase EMs. However, the function of autophagic activity in secretory-phase EMs is still unclear. METHODS: In our work, we explored autophagic activity between normal endometrium and EMs lesion endometrium during different menstrual phases and EMs stages. The clinical endometrium samples from 73 women were selected in this study, including 30 healthy individuals and 43 patients with EMs (endometrium samples include eutopic and its matched ectopic endometrium). All the participants were divided into two groups according to the menstrual cycle, namely proliferative-phase and secretive- phase group. Among the patients with EMs, 22 individuals in proliferative phase and the other 21 individuals in secretory phase were further classified into the groups of Stage I-II and Stage III-IV according to revised-American Fertility Society (r-AFS). Two autophagy-related proteins microtubuleassociated protein 1 light chain 3 beta-II (LC3B-II) and sequestosome protein (P62), which are believed to be the indicators of autophagy activity, were chosen in the study. Immunohistochemical (IHC) staining, Western blot assay and Real-Time quantitative Polymerase Chain Reaction (RTqPCR) were used to examine the expression of LC3B-II and P62 in protein and mRNA level accordingly. RESULT: It showed that the expression of LC3B-II both in protein and mRNA level decreased and that of P62 increased in secretory phase of the healthy group (P<0.05), but showed no significant difference in ectopic and its eutopic endometrium group during proliferative and secretory phase (P>0.05). In addition, the expression of LC3B-II in ectopic endometrium group was significantly lower than that of its eutopic endometrium group (P<0.05), and the expression of P62 was significantly higher accordingly (P<0.05). At the same time, both LC3B-II and P62 levels remained same between eutopic endometrium group and control group (P>0.05). Furthermore, compared to Stage I-II EMs group, the expression of LC3B-II was significantly lower (P<0.05) and P62 was significantly higher (P<0.05) in Stage III-IV EMs during secretory phase. CONCLUSION: Taken together, the periodicity-losing in EMs and the decreased autophagic activity in ectopic endometrium may exert a potential role in the pathogenesis of EMs. Down-regulated autophagy of ectopic endometrium in secretory phase may be related to the progression of EMs.
Assuntos
Proteínas Relacionadas à Autofagia/genética , Autofagia/genética , Endometriose/genética , Endométrio/metabolismo , Adulto , Proteínas Relacionadas à Autofagia/metabolismo , Progressão da Doença , Endometriose/metabolismo , Endometriose/patologia , Feminino , Expressão Gênica , Humanos , Ciclo Menstrual , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Proteína Sequestossoma-1/genética , Proteína Sequestossoma-1/metabolismoRESUMO
Although silver nanoparticles (AgNPs) are widely used in consumer and medical products, the mechanism by which AgNPs cause pulmonary damage is unclear. AgNPs are incorporated into cells and processed via the autophagy pathway. We examined the effects of AgNP exposure on autophagic flux and expression of transcription factor EB (TFEB) in A549 lung adenocarcinoma cells. In cells exposed to citrate-coated 60-nm AgNPs, confocal laser microscopic examination showed a decrease in the LysoTracker fluorescence signal and an increase in that of Cyto-ID, indicating lysosomal pH alkalization and autophagosome formation, respectively. The proteins p62 and microtubule-associated protein light chain 3B-II (LC3B-II) are both degraded by autophagy, and their levels increased depending on AgNP dose. Furthermore, AgNP-induced increase in LC3B-II was not enhanced by treatment with the autophagic inhibitor bafilomycin A1. TFEB mRNA levels, and protein levels in cytosolic and nuclear fractions, were suppressed by exposure to AgNPs, suggesting transcriptional inhibition of TFEB expression. Overexpression of TFEB did not suppress AgNP-induced LC3B-II accumulation and cellular damage, indicating that impairment of autophagic flux and cellular damage by AgNPs might not be primarily caused by reduced TFEB expression. The present study suggests that AgNP-induced lysosomal dysfunction plays a principal role in the autophagic flux defect.
Assuntos
Adenocarcinoma/metabolismo , Autofagia/efeitos dos fármacos , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Lisossomos/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Células A549 , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Nanopartículas Metálicas/química , Prata/químicaRESUMO
Autophagy is an evolutionarily conserved intracellular catabolic process that is essential for cellular housekeeping and nutrient homeostasis. Recently, we provided evidence that thyroid hormone (TH) is a major inducer of autophagy in mammalian cells. Here, we describe a method for detecting TH-induced autophagic flux in hepatic, muscle, and brown adipocyte cells using lysosomal inhibitor bafilomycin A1 (BafA1) and conventional Western blot techniques.
Assuntos
Autofagia/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Hormônios Tireóideos/metabolismo , Adipócitos Marrons/efeitos dos fármacos , Adipócitos Marrons/metabolismo , Animais , Western Blotting , Linhagem Celular , Células Cultivadas , Humanos , Macrolídeos/farmacologia , Proteínas Associadas aos Microtúbulos/metabolismo , Mioblastos/metabolismo , Isoformas de Proteínas , Receptores dos Hormônios Tireóideos/metabolismoRESUMO
Autophagy and inflammation play determinant roles in the pathogenesis of Amyotrophic Lateral Sclerosis (ALS), an adult-onset neurodegenerative disease characterized by deterioration and final loss of upper and lower motor neurons (MN) priming microglia to sustain neuroinflammation and a vicious cycle of neurodegeneration. Given that extracellular ATP through P2X7 receptor constitutes a neuron-to-microglia alarm signal implicated in ALS, and that P2X7 affects autophagy in immune cells, we have investigated if autophagy can be directly triggered by P2X7 activation in primary microglia from superoxide dismutase 1 (SOD1)-G93A mice. We report that P2X7 enhances the expression of the autophagic marker microtubule-associated protein 1 light chain 3 (LC3)-II, via mTOR pathway and concomitantly with modulation of anti-inflammatory M2 microglia markers. We also demonstrate that the autophagic target SQSTM1/p62 is decreased in SOD1-G93A microglia after a short stimulation of P2X7, but increased after a sustained challenge. These effects are prevented by the P2X7 antagonist A-804598, and the autophagy/phosphoinositide-3-kinase inhibitor wortmannin (WM). Finally, a chronic in vivo treatment with A-804598 in SOD1-G93A mice decreases the expression of SQSTM1/p62 in lumbar spinal cord at end stage of disease. These data identify the modulation of the autophagic flux as a novel mechanism by which P2X7 activates ALS-microglia, to be considered for further investigations in ALS.
RESUMO
Autophagy is a major molecular mechanism that eliminates cellular damage in eukaryotic organisms. Basal levels of autophagy are required for maintaining cellular homeostasis and functioning. Defects in the autophagic process are implicated in the development of various age-dependent pathologies including cancer and neurodegenerative diseases, as well as in accelerated aging. Genetic activation of autophagy has been shown to retard the accumulation of damaged cytoplasmic constituents, delay the incidence of age-dependent diseases, and extend life span in genetic models. This implies that autophagy serves as a therapeutic target in treating such pathologies. Although several autophagy-inducing chemical agents have been identified, the majority of them operate upstream of the core autophagic process, thereby exerting undesired side effects. Here, we screened a small-molecule library for specific inhibitors of MTMR14, a myotubularin-related phosphatase antagonizing the formation of autophagic membrane structures, and isolated AUTEN-67 (autophagy enhancer-67) that significantly increases autophagic flux in cell lines and in vivo models. AUTEN-67 promotes longevity and protects neurons from undergoing stress-induced cell death. It also restores nesting behavior in a murine model of Alzheimer disease, without apparent side effects. Thus, AUTEN-67 is a potent drug candidate for treating autophagy-related diseases.
Assuntos
Envelhecimento/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Naftoquinonas/farmacologia , Fármacos Neuroprotetores/farmacologia , Sulfonamidas/farmacologia , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/metabolismo , Corpo Adiposo/efeitos dos fármacos , Corpo Adiposo/metabolismo , Feminino , Células HeLa , Humanos , Longevidade/efeitos dos fármacos , Masculino , Camundongos , Naftoquinonas/química , Comportamento de Nidação/efeitos dos fármacos , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores/química , Estresse Oxidativo/efeitos dos fármacos , Monoéster Fosfórico Hidrolases/metabolismo , Sulfonamidas/química , Peixe-ZebraRESUMO
Bioactive sphingolipids including ceramides are involved in a variety of pathophysiological processes by regulating cell death and survival. The objective of the current study was to examine ceramide metabolism in preeclampsia, a serious disorder of pregnancy characterized by oxidative stress, and increased trophoblast cell death and autophagy. Maternal circulating and placental ceramide levels quantified by tandem mass spectrometry were elevated in pregnancies complicated by preeclampsia. Placental ceramides were elevated due to greater de novo synthesis via high serine palmitoyltransferase activity and reduced lysosomal breakdown via diminished ASAH1 expression caused by TGFB3-induced E2F4 transcriptional repression. SMPD1 activity was reduced; hence, sphingomyelin degradation by SMPD1 did not contribute to elevated ceramide levels in preeclampsia. Oxidative stress triggered similar changes in ceramide levels and acid hydrolase expression in villous explants and trophoblast cells. MALDI-imaging mass spectrometry localized the ceramide increases to the trophophoblast layers and syncytial knots of placentae from pregnancies complicated by preeclampsia. ASAH1 inhibition or ceramide treatment induced autophagy in human trophoblast cells via a shift of the BOK-MCL1 rheostat toward prodeath BOK. Pharmacological inhibition of ASAH1 activity in pregnant mice resulted in increased placental ceramide content, abnormal placentation, reduced fetal growth, and increased autophagy via a similar shift in the BOK-MCL1 system. Our results reveal that oxidative stress-induced reduction of lysosomal hydrolase activities in combination with elevated de novo synthesis leads to ceramide overload, resulting in increased trophoblast cell autophagy, and typifies preeclampsia as a sphingolipid storage disorder.
Assuntos
Autofagia/efeitos dos fármacos , Ceramidas/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Placenta/metabolismo , Pré-Eclâmpsia/metabolismo , Esfingolipídeos/metabolismo , Animais , Autofagia/fisiologia , Células Cultivadas , Feminino , Humanos , Camundongos , Pré-Eclâmpsia/tratamento farmacológico , GravidezRESUMO
The standard of care for unresectable lung cancer is chemoradiation. However, therapeutic options are limited and patients are rarely cured. We have previously shown that vitamin D and vitamin D analogs such as EB 1089 can enhance the response to radiation in breast cancer through the promotion of a cytotoxic form of autophagy. In A549 and H460 non-small cell lung cancer (NSCLC) cells, 1,25-D3 (the hormonally active form of vitamin D) and EB 1089 prolonged the growth arrest induced by radiation alone and suppressed proliferative recovery, which translated to a significant reduction in clonogenic survival. In H838 or H358 NSCLC cells, which lack VDR/vitamin D receptor or functional TP53, respectively, 1,25-D3 failed to modify the extent of radiation-induced growth arrest or suppress proliferative recovery post-irradiation. Sensitization to radiation in H1299 NSCLC cells was evident only when TP53 was induced in otherwise tp53-null H1299 NSCLC cells. Sensitization was not associated with increased DNA damage, decreased DNA repair or an increase in apoptosis, necrosis, or senescence. Instead sensitization appeared to be a consequence of the conversion of the cytoprotective autophagy induced by radiation alone to a novel cytostatic form of autophagy by the combination of 1,25-D3 or EB 1089 with radiation. While both pharmacological and genetic suppression of autophagy or inhibition of AMPK phosphorylation sensitized the NSCLC cells to radiation alone, inhibition of the cytostatic autophagy induced by the combination treatment reversed sensitization. Evidence for selectivity was provided by lack of radiosensitization in normal human bronchial cells and cardiomyocytes. Taken together, these studies have identified a unique cytostatic function of autophagy that appears to be mediated by VDR, TP53, and possibly AMPK in the promotion of an enhanced response to radiation by 1,25-D3 and EB 1089 in NSCLC.