RESUMO
During skeletal myogenesis, the zinc-finger transcription factors SNAI1 and SNAI2, are expressed in proliferating myoblasts and regulate the transition to terminally differentiated myotubes while repressing pro-differentiation genes. Here, we demonstrate that SNAI1 is upregulated in vivo during the early phase of muscle regeneration induced by bupivacaine injury. Using shRNA-mediated gene silencing in C2C12 myoblasts and whole-transcriptome microarray analysis, we identified a collection of genes belonging to the endoplasmic reticulum (ER) stress pathway whose expression, induced by myogenic differentiation, was upregulated in absence of SNAI1. Among these, key ER stress genes, such as Atf3, Ddit3/Chop, Hspa5/Bip, and Fgf21, a myokine involved in muscle differentiation, were strongly upregulated. Furthermore, by promoter mutant analysis and Chromatin immune precipitation assay, we demonstrated that SNAI1 represses Fgf21 and Atf3 in proliferating myoblasts by directly binding to multiple E boxes in their respective promoter regions. Together, these data describe a new regulatory mechanism of myogenic differentiation involving the direct repressive action of SNAI1 on ER stress and Fgf21 expression, ultimately contributing to maintaining the proliferative and undifferentiated state of myoblasts.
Assuntos
Desenvolvimento Muscular , Fibras Musculares Esqueléticas , Fatores de Transcrição da Família Snail/metabolismo , Fator 3 Ativador da Transcrição/metabolismo , Diferenciação Celular , Linhagem Celular , Fatores de Crescimento de Fibroblastos , Desenvolvimento Muscular/genética , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/fisiologia , Regiões Promotoras Genéticas/genética , Regulação para CimaRESUMO
Epiretinal membranes (ERMs) are sheets of tissue that pathologically develop in the vitreoretinal interface leading to progressive vision loss. They are formed by different cell types and by an exuberant deposition of extracellular matrix proteins. Recently, we reviewed ERMs' extracellular matrix components to better understand molecular dysfunctions that trigger and fuel the onset and development of this disease. The bioinformatics approach we applied delineated a comprehensive overview on this fibrocellular tissue and on critical proteins that could really impact ERM physiopathology. Our interactomic analysis proposed the hyaluronic-acid-receptor cluster of differentiation 44 (CD44) as a central regulator of ERM aberrant dynamics and progression. Interestingly, the interaction between CD44 and podoplanin (PDPN) was shown to promote directional migration in epithelial cells. PDPN is a glycoprotein overexpressed in various cancers and a growing body of evidence indicates its relevant function in several fibrotic and inflammatory pathologies. The binding of PDPN to partner proteins and/or its ligand results in the modulation of signaling pathways regulating proliferation, contractility, migration, epithelial-mesenchymal transition, and extracellular matrix remodeling, all processes that are vital in ERM formation. In this context, the understanding of the PDPN role can help to modulate signaling during fibrosis, hence opening a new line of therapy.
Assuntos
Membrana Epirretiniana , Vitreorretinopatia Proliferativa , Humanos , Membrana Epirretiniana/metabolismo , Membrana Epirretiniana/patologia , Proteínas da Matriz Extracelular , Fibrose , Receptores de Hialuronatos/genética , Receptores de Hialuronatos/metabolismo , Fatores de Transcrição , Vitreorretinopatia Proliferativa/metabolismoRESUMO
BACKGROUND: In Neisseria meningitidis the HrpA/HrpB two-partner secretion system (TPS) was implicated in diverse functions including meningococcal competition, biofilm formation, adherence to epithelial cells, intracellular survival and vacuolar escape. These diverse functions could be attributed to distinct domains of secreted HrpA. METHODS: A yeast two-hybrid screening, in vitro pull-down assay and immunofluorescence microscopy experiments were used to investigate the interaction between HrpA and the dynein light-chain, Tctex-type 1 (DYNLT1). In silico modeling was used to analyze HrpA structure. Western blot analysis was used to investigate apoptotic and pyroptotic markers. RESULTS: The HrpA carboxy-terminal region acts as a manganese-dependent cell lysin, while the results of a yeast two-hybrid screening demonstrated that the HrpA middle region has the ability to bind the dynein light-chain, Tctex-type 1 (DYNLT1). This interaction was confirmed by in vitro pull-down assay and immunofluorescence microscopy experiments showing co-localization of N. meningitidis with DYNLT1 in infected epithelial cells. In silico modeling revealed that the HrpA-M interface interacting with the DYNLT1 has similarity with capsid proteins of neurotropic viruses that interact with the DYNLT1. Indeed, we found that HrpA plays a key role in infection of and meningococcal trafficking within neuronal cells, and is implicated in the modulation of the balance between apoptosis and pyroptosis. CONCLUSIONS: Our findings revealed that N. meningitidis is able to effectively infect and survive in neuronal cells, and that this ability is dependent on HrpA, which establishes a direct protein-protein interaction with DYNLTI in these cells, suggesting that the HrpA interaction with dynein could be fundamental for N. meningitidis spreading inside the neurons. Moreover, we found that the balance between apoptotic and pyroptotic pathways is heavily affected by HrpA.
Assuntos
Dineínas , Neisseria meningitidis , Dineínas/química , Dineínas/metabolismo , Células Epiteliais/metabolismo , Neisseria meningitidis/metabolismo , Piroptose , Saccharomyces cerevisiae/metabolismoRESUMO
Oxidative stress plays a key role in the pathophysiology of retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy, which are the major causes of irreversible blindness in developed countries. An excess of reactive oxygen species (ROS) can directly cause functional and morphological impairments in retinal pigment epithelium (RPE), endothelial cells, and retinal ganglion cells. Antioxidants may represent a preventive/therapeutic strategy and reduce the risk of progression of AMD. Among antioxidants, N-acetyl-L-cysteine (NAC) is widely studied and has been proposed to have therapeutic benefit in treating AMD by mitigating oxidative damage in RPE. Here, we demonstrate that N-acetyl-L-cysteine ethyl ester (NACET), a lipophilic cell-permeable cysteine derivative, increases the viability in oxidative stressed RPE cells more efficiently than NAC by reacting directly and more rapidly with oxidizing agents, and that NACET, but not NAC, pretreatment predisposes RPE cells to oxidative stress resistance and increases the intracellular reduced glutathione (GSH) pool available to act as natural antioxidant defense. Moreover, we demonstrate the ability of NACET to increase GSH levels in rats' eyes after oral administration. In conclusion, even if experiments in AMD animal models are still needed, our data suggest that NACET may play an important role in preventing and treating retinal diseases associated with oxidative stress, and may represent a valid and more efficient alternative to NAC in therapeutic protocols in which NAC has already shown promising results.
Assuntos
Acetilcisteína/farmacologia , Antioxidantes/farmacologia , Cisteína/análogos & derivados , Estresse Oxidativo/efeitos dos fármacos , Epitélio Pigmentado da Retina/efeitos dos fármacos , Acetilcisteína/análogos & derivados , Animais , Antioxidantes/química , Linhagem Celular , Cisteína/química , Cisteína/farmacologia , Humanos , Masculino , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Epitélio Pigmentado da Retina/citologia , Epitélio Pigmentado da Retina/metabolismoRESUMO
Autophagy, a pathway for bulk protein degradation and removal of damaged organelles, represents one of the major responses of cells to stress, thereby exerting a strict control on their correct functioning. Consequently, this process has been involved in the pathogenesis and therapeutic responses of several human diseases. Mitogen-activated protein (MAP) kinase 15 (MAPK15) is an atypical member of the MAP kinase family that recently emerged as a key modulator of autophagy and, through this, of cell transformation. Still, no information is available about signaling pathways mediating the effect of MAPK15 on this process, nor is it known which phase of autophagosome biogenesis is affected by this MAP kinase. Here, we demonstrate that MAPK15 stimulated 5'-AMP-activated protein kinase-dependent activity of UNC-51-like kinase 1 (ULK1), the only protein kinase among the ATG-related proteins, toward downstream substrates and signaling intermediates. Importantly, MAPK15 directly interacted with the ULK1 complex and mediated ULK1 activation induced by starvation, a classical stimulus for the autophagic process. In turn, ULK1 and its highly homologous protein ULK2 are able to transduce MAPK15 signals stimulating early phases of autophagosomal biogenesis in a multikinase cascade that offers numerous potential targets for future therapeutic intervention in cancer and other autophagy-related human diseases.
Assuntos
Proteína Homóloga à Proteína-1 Relacionada à Autofagia/fisiologia , Autofagia/fisiologia , MAP Quinases Reguladas por Sinal Extracelular/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Transdução de Sinais/fisiologia , Autofagossomos/fisiologia , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/genética , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Regulação para Baixo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Células HEK293 , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Complexos Multiproteicos/fisiologia , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/fisiologia , RNA Interferente Pequeno/genéticaRESUMO
14-3-3 are regulatory proteins that through protein-protein interactions (PPI) with numerous binding partners could be involved in several human diseases, including cancer, neurodegenerative disorders, and pathogens infections. Following our research interest in the development of 14-3-3 PPI inhibitors, here we exploited the privileged 4-aminoantipyrine scaffold in the design and synthesis of some derivatives endowed with antiproliferative activity against K-562 cells, and capable of binding to recombinant 14-3-3σ as evidenced by NMR spectroscopy. The binding mode was further explored by molecular modelling, while coupling confocal microscopy with intensitometric analysis showed that compound 1 was able to promote the nuclear translocation of c-Abl at low micromolar concentrations. Overall, 1 is chemically stable compared to parent 14-3-3 PPI inhibitors, and thus emerged as a confirmed hit for further development.
Assuntos
Proteínas 14-3-3/antagonistas & inibidores , Antineoplásicos/farmacologia , Benzamidas/farmacologia , Pirazóis/farmacologia , Proteínas 14-3-3/química , Proteínas 14-3-3/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Benzamidas/síntese química , Benzamidas/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Células K562 , Estrutura Molecular , Ligação Proteica/efeitos dos fármacos , Pirazóis/síntese química , Pirazóis/química , Relação Estrutura-AtividadeRESUMO
AIDS-related cancer diseases are malignancies with low incidence on healthy people that affect mostly subjects already immunocompromised. The connection between HIV/AIDS and these cancers has not been established yet, but a weakened immune system is certainly the main cause. We envisaged the possibility to screen a small library of compounds synthesized in our laboratory against opportunistic tumors mainly due to HIV infection like Burkitt's Lymphoma. From cellular assays and gene expression analysis we identified two promising compounds. These derivatives have the dual action required inhibiting HIV replication in human TZM-bl cells infected with HIV-1 NL4.3 and showing cytotoxic activity on human colon HT-29 and breast adenocarcinoma MCF-7 cells. In addition, preclinical in vitro adsorption, distribution, metabolism, and excretion studies highlighted a satisfactory pharmacokinetic profile.
Assuntos
Antirretrovirais/química , Antirretrovirais/metabolismo , Antirretrovirais/farmacologia , Antirretrovirais/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , HIV-1/efeitos dos fármacos , Células HT29 , Humanos , Células MCF-7 , Microssomos Hepáticos/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Telomerase/genética , Telomerase/metabolismoRESUMO
Pyrazolo[3,4-d]pyrimidine derivatives 1-5, active as c-Src inhibitors, have been selected to be formulated as drug-loaded human serum albumin (HSA) nanoparticles, with the aim of improving their solubility and pharmacokinetic properties. The present study includes the optimization of a desolvation method-based procedure for preparing HSA nanoparticles. First, characterization by HPLC-MS and Dynamic Light Scattering (DLS) showed a good entrapment efficacy, a controllable particle size (between 100 and 200nm) and an optimal stability over time, confirmed by an in vitro drug release assay. Then, 1-4 and the corresponding NPs were tested for their antiproliferative activity against neuroblastoma SH-SY5Y cell line. Notably, 3-NPs and 4-NPs were identified as the most promising formulation showing a profitable balance of stability, small size and a similar activity compared to the free drugs in cell-based assays. In addition, albumin formulations increase the solubility of pyrazolo[3,4-d]pyrimidine avoiding the use of DMSO as solubilizing agent.
Assuntos
Nanopartículas/química , Pirazóis/química , Pirimidinas/química , Albumina Sérica/química , Proteína Tirosina Quinase CSK , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Portadores de Fármacos/química , Composição de Medicamentos , Liberação Controlada de Fármacos , Difusão Dinâmica da Luz , Humanos , Espectrometria de Massas , Nanopartículas/toxicidade , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Tamanho da Partícula , Solubilidade , Quinases da Família src/metabolismoRESUMO
BV02 is a reference inhibitor of 14-3-3 protein-protein interactions, which is currently used as chemical biology tool to understand the role of 14-3-3 proteins in pathological contexts. Due to chemical instability in certain conditions, its bioactive form has remained unclear. Here, we use NMR spectroscopy to prove for the first time the direct interaction between the molecule and 14-3-3σ, and to depict its bioactive form, namely the phthalimide derivative 9. Our work provides molecular insights to the bioactive form of the 14-3-3 PPI inhibitor and facilitates further development as candidate therapeutic agent.
Assuntos
Proteínas 14-3-3/antagonistas & inibidores , Benzamidas/química , Pirazóis/química , Proteínas 14-3-3/metabolismo , Benzamidas/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Ftalimidas/química , Ftalimidas/metabolismo , Domínios e Motivos de Interação entre Proteínas , Pirazóis/metabolismoRESUMO
In the past decade, we have observed exciting advances in lung cancer therapy, including the development of targeted therapies. However, additional strategies for early detection and tumor-based therapy are still essential in improving patient outcomes. EGF receptor (EGFR) and MET (the receptor tyrosine kinase for hepatocyte growth factors) are cell-surface tyrosine kinase receptors that have been implicated in diverse cellular processes and as regulators of several microRNAs (miRNAs), thus contributing to tumor progression. Here, we demonstrate a biological link between EGFR, MET, and the miRNA cluster 23a ~ 27a ~ 24-2. We show that miR-27a regulates MET, EGFR, and Sprouty2 in lung cancer. In addition, we identify both direct and indirect mechanisms by which miR-27a can regulate both MET and EGFR. Thus, we propose a mechanism for MET and EGFR axis regulation that may lead to the development of therapeutics in lung cancer.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Receptores ErbB/biossíntese , Regulação Neoplásica da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/biossíntese , Neoplasias Pulmonares/metabolismo , MicroRNAs/metabolismo , Proteínas Proto-Oncogênicas c-met/biossíntese , RNA Neoplásico/metabolismo , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Receptores ErbB/genética , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Proteínas de Membrana , MicroRNAs/genética , Proteínas Proto-Oncogênicas c-met/genética , RNA Neoplásico/genéticaRESUMO
Oxidation processes in mitochondria and different environmental insults contribute to unwarranted accumulation of reactive oxygen species (ROS). These, in turn, rapidly damage intracellular lipids, proteins, and DNA, ultimately causing aging and several human diseases. Cells have developed different and very effective systems to control ROS levels. Among these, removal of excessive amounts is guaranteed by upregulated expression of various antioxidant enzymes, through activation of the NF-E2-Related Factor 2 (NRF2) protein. Here, we show that Mitogen Activated Protein Kinase 15 (MAPK15) controls the transactivating potential of NRF2 and, in turn, the expression of its downstream target genes. Specifically, upon oxidative stress, MAPK15 is necessary to increase NRF2 expression and nuclear translocation, by inducing its activating phosphorylation, ultimately supporting transactivation of cytoprotective antioxidant genes. Lungs are continuously exposed to oxidative damages induced by environmental insults such as air pollutants and cigarette smoke. Interestingly, we demonstrate that MAPK15 is very effective in supporting NRF2-dependent antioxidant transcriptional response to cigarette smoke of epithelial lung cells. Oxidative damage induced by cigarette smoke indeed represents a leading cause of disability and death worldwide by contributing to the pathogenesis of different chronic respiratory diseases and lung cancer. Therefore, the development of novel therapeutic strategies able to modulate cellular responses to oxidative stress would be highly beneficial. Our data contribute to the necessary understanding of the molecular mechanisms behind such responses and identify new potentially actionable targets.
Assuntos
MAP Quinases Reguladas por Sinal Extracelular , Regulação da Expressão Gênica , Fator 2 Relacionado a NF-E2 , Estresse Oxidativo , Espécies Reativas de Oxigênio , Animais , Humanos , Camundongos , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fosforilação , Espécies Reativas de Oxigênio/metabolismo , Ativação Transcricional , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismoRESUMO
Triple-negative breast cancer (TNBC) is a very aggressive and heterogeneous group of tumors. In order to develop effective therapeutic strategies, it is therefore essential to identify the subtype-specific molecular mechanisms underlying disease progression and resistance to chemotherapy. TNBC cells are highly dependent on exogenous cystine, provided by overexpression of the cystine/glutamate antiporter SLC7A11/xCT, to fuel glutathione synthesis and promote an oxidative stress response consistent with their high metabolic demands. Here we show that TNBC cells of the mesenchymal stem-like subtype (MSL) utilize forced cystine uptake to induce activation of the transcription factor NRF2 and promote a glutathione-independent mechanism to defend against oxidative stress. Mechanistically, we demonstrate that NRF2 activation is mediated by direct cysteinylation of the inhibitor KEAP1. Furthermore, we show that cystine-mediated NRF2 activation induces the expression of important genes involved in oxidative stress response, but also in epithelial-to-mesenchymal transition and stem-like phenotype. Remarkably, in survival analysis, four upregulated genes (OSGIN1, RGS17, SRXN1, AKR1B10) are negative prognostic markers for TNBC. Finally, expression of exogenous OSGIN1, similarly to expression of exogenous NRF2, can prevent cystine depletion-dependent death of MSL TNBC cells. The results suggest that the cystine/NRF2/OSGIN1 axis is a potential target for effective treatment of MSL TNBCs.
Assuntos
Fator 2 Relacionado a NF-E2 , Estresse Oxidativo , Neoplasias de Mama Triplo Negativas , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Neoplasias de Mama Triplo Negativas/genética , Humanos , Feminino , Linhagem Celular Tumoral , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Cisteína/metabolismo , Transição Epitelial-Mesenquimal/genética , Sistema y+ de Transporte de Aminoácidos/metabolismo , Sistema y+ de Transporte de Aminoácidos/genética , Regulação Neoplásica da Expressão Gênica , Sobrevivência Celular/genéticaRESUMO
Glioblastoma (GB) is a highly malignant primary brain tumor with limited treatment options and poor prognosis. Despite current treatment approaches, including surgical resection, radiation therapy, and chemotherapy with temozolomide (TMZ), GB remains mostly incurable due to its invasive growth pattern, limited drug penetration beyond the blood-brain barrier (BBB), and resistance to conventional therapies. One of the main challenges in GB treatment is effectively eliminating infiltrating cancer cells that remain in the brain parenchyma after primary tumor resection. We've reviewed the most recent challenges and surveyed the potential strategies aimed at enhancing local treatment outcomes.
RESUMO
Glioblastoma multiforme (GBM) is the most aggressive primary tumor of the central nervous system and the diagnosis is often dismal. GBM pharmacological treatment is strongly limited by its intracranial location beyond the blood-brain barrier (BBB). While Temozolomide (TMZ) exhibits the best clinical performance, still less than 20% crosses the BBB, therefore requiring administration of very high doses with resulting unnecessary systemic side effects. Here, we aimed at designing new negative temperature-responsive gel formulations able to locally release TMZ beyond the BBB. The biocompatibility of a chitosan-ß-glycerophosphate-based thermogel (THG)-containing mesoporous SiO2 nanoparticles (THG@SiO2) or polycaprolactone microparticles (THG@PCL) was ascertained in vitro and in vivo by cell counting and histological examination. Next, we loaded TMZ into such matrices (THG@SiO2-TMZ and THG@PCL-TMZ) and tested their therapeutic potential both in vitro and in vivo, in a glioblastoma resection and recurrence mouse model based on orthotopic growth of human cancer cells. The two newly designed anticancer formulations, consisting in TMZ-silica (SiO2@TMZ) dispersed in the thermogel matrix (THG@SiO2-TMZ) and TMZ, spray-dried on PLC and incorporated into the thermogel (THG@PCL-TMZ), induced cell death in vitro. When applied intracranially to a resected U87-MG-Red-FLuc human GBM model, THG@SiO2-TMZ and THG@PCL-TMZ caused a significant reduction in the growth of tumor recurrences, when compared to untreated controls. THG@SiO2-TMZ and THG@PCL-TMZ are therefore new promising gel-based local therapy candidates for the treatment of GBM.
Assuntos
Neoplasias Encefálicas , Glioblastoma , Camundongos , Animais , Humanos , Temozolomida/farmacologia , Temozolomida/uso terapêutico , Glioblastoma/patologia , Xenoenxertos , Dióxido de Silício/farmacologia , Linhagem Celular Tumoral , Recidiva Local de Neoplasia/prevenção & controle , Recidiva Local de Neoplasia/tratamento farmacológico , Neoplasias Encefálicas/patologia , Ensaios Antitumorais Modelo de Xenoenxerto , Resistencia a Medicamentos Antineoplásicos , Antineoplásicos Alquilantes/farmacologia , Antineoplásicos Alquilantes/uso terapêuticoRESUMO
ERK8 (MAPK15) is a large MAP kinase already implicated in the regulation of the functions of different nuclear receptors and in cellular proliferation and transformation. Here, we identify ERRα as a novel ERK8-interacting protein. As a consequence of such interaction, ERK8 induces CRM1-dependent translocation of ERRα to the cytoplasm and inhibits its transcriptional activity. Also, we identify in ERK8 two LXXLL motifs, typical of agonist-bound nuclear receptor corepressors, as necessary features for this MAP kinase to interact with ERRα and to regulate its cellular localization and transcriptional activity. Ultimately, we demonstrate that ERK8 is able to counteract, in immortalized human mammary cells, ERRα activation induced by the EGF receptor pathway, often deregulated in breast cancer. Altogether, these results reveal a novel function for ERK8 as a bona fide ERRα corepressor, involved in control of its cellular localization by nuclear exclusion, and suggest a key role for this MAP kinase in the regulation of the biological activities of this nuclear receptor.
Assuntos
Núcleo Celular/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Receptores de Estrogênio/metabolismo , Transcrição Gênica/fisiologia , Transporte Ativo do Núcleo Celular/fisiologia , Motivos de Aminoácidos , Animais , Núcleo Celular/genética , MAP Quinases Reguladas por Sinal Extracelular/genética , Células HEK293 , Células HeLa , Humanos , Carioferinas/genética , Carioferinas/metabolismo , Camundongos , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores de Estrogênio/genética , Proteína Exportina 1 , Receptor ERRalfa Relacionado ao EstrogênioRESUMO
Iron is essential for deoxyribonucleotides production and for enzymes containing an Fe-S cluster involved in DNA replication and repair. How iron bioavailability and DNA metabolism are coordinated remains poorly understood. NCOA4 protein mediates autophagic degradation of ferritin to maintain iron homeostasis and inhibits DNA replication origin activation via hindrance of the MCM2-7 DNA helicase. Here, we show that iron deficiency inhibits DNA replication, parallel to nuclear NCOA4 stabilization. In iron-depleted cells, NCOA4 knockdown leads to unscheduled DNA synthesis, with replication stress, genome instability, and cell death. In mice, NCOA4 genetic inactivation causes defective intestinal regeneration upon dextran sulfate sodium-mediated injury, with DNA damage, defective cell proliferation, and cell death; in intestinal organoids, this is fostered by iron depletion. In summary, we describe a NCOA4-dependent mechanism that coordinates iron bioavailability and DNA replication. This function prevents replication stress, maintains genome integrity, and sustains high rates of cell proliferation during tissue regeneration.
Assuntos
Ferro , Coativadores de Receptor Nuclear , Animais , Disponibilidade Biológica , DNA/metabolismo , Replicação do DNA , Ferritinas/metabolismo , Ferro/metabolismo , Camundongos , Coativadores de Receptor Nuclear/genética , Fatores de Transcrição/metabolismoRESUMO
Mitochondria are the major source of reactive oxygen species (ROS), whose aberrant production by dysfunctional mitochondria leads to oxidative stress, thus contributing to aging as well as neurodegenerative disorders and cancer. Cells efficiently eliminate damaged mitochondria through a selective type of autophagy, named mitophagy. Here, we demonstrate the involvement of the atypical MAP kinase family member MAPK15 in cellular senescence, by preserving mitochondrial quality, thanks to its ability to control mitophagy and, therefore, prevent oxidative stress. We indeed demonstrate that reduced MAPK15 expression strongly decreases mitochondrial respiration and ATP production, while increasing mitochondrial ROS levels. We show that MAPK15 controls the mitophagic process by stimulating ULK1-dependent PRKN Ser108 phosphorylation and inducing the recruitment of damaged mitochondria to autophagosomal and lysosomal compartments, thus leading to a reduction of their mass, but also by participating in the reorganization of the mitochondrial network that usually anticipates their disposal. Consequently, MAPK15-dependent mitophagy protects cells from accumulating nuclear DNA damage due to mitochondrial ROS and, consequently, from senescence deriving from this chronic DNA insult. Indeed, we ultimately demonstrate that MAPK15 protects primary human airway epithelial cells from senescence, establishing a new specific role for MAPK15 in controlling mitochondrial fitness by efficient disposal of old and damaged organelles and suggesting this kinase as a new potential therapeutic target in diverse age-associated human diseases.
Assuntos
Senescência Celular , MAP Quinases Reguladas por Sinal Extracelular , Mitofagia , Autofagia/genética , Senescência Celular/genética , Senescência Celular/fisiologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Mitofagia/genética , Mitofagia/fisiologia , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
The polymorphism L412F in TLR3 has been associated with several infectious diseases. However, the mechanism underlying this association is still unexplored. Here, we show that the L412F polymorphism in TLR3 is a marker of severity in COVID-19. This association increases in the sub-cohort of males. Impaired macroautophagy/autophagy and reduced TNF/TNFα production was demonstrated in HEK293 cells transfected with TLR3L412F-encoding plasmid and stimulated with specific agonist poly(I:C). A statistically significant reduced survival at 28 days was shown in L412F COVID-19 patients treated with the autophagy-inhibitor hydroxychloroquine (p = 0.038). An increased frequency of autoimmune disorders such as co-morbidity was found in L412F COVID-19 males with specific class II HLA haplotypes prone to autoantigen presentation. Our analyses indicate that L412F polymorphism makes males at risk of severe COVID-19 and provides a rationale for reinterpreting clinical trials considering autophagy pathways.Abbreviations: AP: autophagosome; AUC: area under the curve; BafA1: bafilomycin A1; COVID-19: coronavirus disease-2019; HCQ: hydroxychloroquine; RAP: rapamycin; ROC: receiver operating characteristic; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; TLR: toll like receptor; TNF/TNF-α: tumor necrosis factor.
Assuntos
COVID-19 , Receptor 3 Toll-Like , Autofagia/genética , Biomarcadores , COVID-19/genética , Células HEK293 , Humanos , Hidroxicloroquina/uso terapêutico , Masculino , Polimorfismo de Nucleotídeo Único , SARS-CoV-2/genética , Índice de Gravidade de Doença , Receptor 3 Toll-Like/genéticaRESUMO
RAB7A is a small GTPase that controls the late endocytic pathway but also cell migration through RAC1 (Ras-related C3 botulinum toxin substrate 1) and vimentin. In fact, RAB7A regulates vimentin phosphorylation at different sites and vimentin assembly, and, in this study, we identified vimentin domains interacting with RAB7A. As several kinases could be responsible for vimentin phosphorylation, we investigated whether modulation of RAB7A expression affects the activity of these kinases. We discovered that RAB7A regulates AKT and PAK1, and we demonstrated that increased vimentin phosphorylation at Ser38 (Serine 38), observed upon RAB7A overexpression, is due to AKT activity. As AKT and PAK1 are key regulators of several cellular events, we investigated if RAB7A could have a role in these processes by modulating AKT and PAK1 activity. We found that RAB7A protein levels affected beta-catenin and caspase 9 expression. We also observed the downregulation of cofilin-1 and decreased matrix metalloproteinase 2 (MMP2) activity upon RAB7A silencing. Altogether these results demonstrate that RAB7A regulates AKT and PAK1 kinases, affecting their downstream effectors and the processes they regulate, suggesting that RAB7A could have a role in a number of cancer hallmarks.
RESUMO
In medulloblastomas, genetic alterations resulting in over-activation and/or deregulation of proteins involved in Hedgehog (HH) signaling lead to cellular transformation, which can be prevented by inhibition of primary ciliogenesis. Here, we investigated the role of MAPK15 in HH signaling and, in turn, in HH-mediated cellular transformation. We first demonstrated, in NIH3T3 mouse fibroblasts, the ability of this kinase of controlling primary ciliogenesis and canonical HH signaling. Next, we took advantage of transformed human medulloblastoma cells belonging to the SHH-driven subtype, i.e., DAOY and ONS-76 cells, to ascertain the role for MAPK15 in HH-mediated cellular transformation. Specifically, medullo-spheres derived from these cells, an established in vitro model for evaluating progression and malignancy of putative tumor-initiating medulloblastoma cells, were used to demonstrate that MAPK15 regulates self-renewal of these cancer stem cell-like cells. Interestingly, by using the HH-related oncogenes SMO-M2 and GLI2-DN, we provided evidences that disruption of MAPK15 signaling inhibits oncogenic HH overactivation in a specific cilia-dependent fashion. Ultimately, we show that pharmacological inhibition of MAPK15 prevents cell proliferation of SHH-driven medulloblastoma cells, overall suggesting that oncogenic HH signaling can be counteracted by targeting the ciliary gene MAPK15, which could therefore be considered a promising target for innovative "smart" therapies in medulloblastomas.