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1.
Adv Exp Med Biol ; 1131: 93-129, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31646508

RESUMO

Plasma membrane Ca2+ transport ATPases (PMCA1-4, ATP2B1-4) are responsible for removing excess Ca2+ from the cell in order to keep the cytosolic Ca2+ ion concentration at the low level essential for normal cell function. While these pumps take care of cellular Ca2+ homeostasis they also change the duration and amplitude of the Ca2+ signal and can create Ca2+ gradients across the cell. This is accomplished by generating more than twenty PMCA variants each having the character - fast or slow response, long or short memory, distinct interaction partners and localization signals - that meets the specific needs of the particular cell-type in which they are expressed. It has become apparent that these pumps are essential to normal tissue development and their malfunctioning can be linked to different pathological conditions such as certain types of neurodegenerative and heart diseases, hearing loss and cancer. In this chapter we summarize the complexity of PMCA regulation and function under normal and pathological conditions with particular attention to recent developments of the field.


Assuntos
Membrana Celular , ATPases Transportadoras de Cálcio da Membrana Plasmática , Animais , Membrana Celular/enzimologia , Membrana Celular/patologia , Citosol/metabolismo , Homeostase/fisiologia , Humanos , ATPases Transportadoras de Cálcio da Membrana Plasmática/genética , ATPases Transportadoras de Cálcio da Membrana Plasmática/metabolismo
2.
Adv Exp Med Biol ; 1131: 699-718, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31646531

RESUMO

Calcium exchanges and homeostasis are finely regulated between cellular organelles and in response to physiological signals. Besides ionophores, including voltage-gated Ca2+ channels, ionotropic neurotransmitter receptors, or Store-operated Ca2+ entry, activity of regulatory intracellular proteins finely tune Calcium homeostasis. One of the most intriguing, by its unique nature but also most promising by the therapeutic opportunities it bears, is the sigma-1 receptor (Sig-1R). The Sig-1R is a chaperone protein residing at mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs), where it interacts with several partners involved in ER stress response, or in Ca2+ exchange between the ER and mitochondria. Small molecules have been identified that specifically and selectively activate Sig-1R (Sig-1R agonists or positive modulators) at the cellular level and that also allow effective pharmacological actions in several pre-clinical models of pathologies. The present review will summarize the recent data on the mechanism of action of Sig-1R in regulating Ca2+ exchanges and protein interactions at MAMs and the ER. As MAMs alterations and ER stress now appear as a common track in most neurodegenerative diseases, the intracellular action of Sig-1R will be discussed in the context of the recently reported efficacy of Sig-1R drugs in pathologies like Alzheimer's disease, Parkinson's disease, Huntington's disease, or amyotrophic lateral sclerosis.


Assuntos
Membrana Celular , Estresse do Retículo Endoplasmático , Doenças Neurodegenerativas , Receptores sigma , Membrana Celular/metabolismo , Membrana Celular/patologia , Humanos , Mitocôndrias/metabolismo , Doenças Neurodegenerativas/fisiopatologia , Receptores sigma/metabolismo
3.
Int J Nanomedicine ; 14: 5061-5071, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31371947

RESUMO

Background: Photodynamic therapy (PDT) is widely recognized as a promising way to cure cancer. However, the limited tumor homing property of currently available drug delivery systems (DDSs) is the bottleneck for the delivery of photodynamic agents. Purpose: In our study, we decorated silica nanoparticles (SLN) with cell membrane (CM) derived from SGC7901 cells to construct carrier (CM/SLN) which was able to to specifically target the homogenous SGC7901 cells. Materials and methods: Furthermore, the decent drug loading capability of CM/SLN was adopted to load photodynamic agent chlorins e6 (Ce6) to finally construct aDDS suitable for tumor-targeted PDT of gastric cancer. Results: The experimental results suggested that CM/SLN/Ce6 was nano-sized particles with good dispersion and stability in physiological conditions. Moreover, due to the modification of CM,CM/SLN/Ce6 could specifically target the homogenous SGC7901 cells both in vitro and in vivo. Most importantly, further in vivo results demonstrated that the CM/SLN/Ce6 showed a better anticancer outcome compared to SLN/Ce6. Conclusion: CM/SLN/Ce6 might be a promising platform for effective tumor targeted PDT of gastric cancer.


Assuntos
Membrana Celular/patologia , Nanopartículas/química , Fotoquimioterapia , Porfirinas/uso terapêutico , Dióxido de Silício/química , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/patologia , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Peso Corporal/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Coloides , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Humanos , Camundongos , Nanopartículas/ultraestrutura , Tamanho da Partícula , Porfirinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Eletricidade Estática , Distribuição Tecidual/efeitos dos fármacos , Carga Tumoral/efeitos dos fármacos
4.
Toxicol Lett ; 313: 137-149, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31254607

RESUMO

Tordon® is the commercial name of a mixture of two organo-chlorinated herbicides, 2,4-D and picloram. Both compounds affect energy transduction in isolated mitochondria and the present study aimed at characterizing the actions of these two compounds on liver metabolism and their cellular distribution in the isolated perfused rat liver. 2,4-D, but not picloram, increased glycolysis in the range from 10 to 400 µM. The redox potential of the cytosolic NAD+-NADH couple was also increased by 2,4-D. Both compounds inhibited lactate gluconeogenesis. Inhibitions by 2,4-D and picloram were incomplete, reaching maximally 46% and 23%, respectively. Both compounds diminished the cellular ATP levels. No synergism between the actions of 2,4-D and picloram was detected. Biotransformations of 2,4-D and picloram were slow, but their distributions occurred at high rates and were concentrative. Molecular dynamics simulations revealed that 2,4-D presented low affinity for the hydrophobic lipid bilayers, the opposite occurring with picloram. Inhibition of energy metabolism is possibly a relevant component of the toxicity of 2,4-D and of the commercial product Tordon®. Furthermore, the interactions of 2,4-D with the membrane lipid bilayer can be highly destructive and might equally be related to its cellular toxicity at high concentrations.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Membrana Celular/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Herbicidas/toxicidade , Bicamadas Lipídicas/metabolismo , Fígado/efeitos dos fármacos , Picloram/toxicidade , Ácido 2,4-Diclorofenoxiacético/metabolismo , Animais , Membrana Celular/metabolismo , Membrana Celular/patologia , Gluconeogênese/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Herbicidas/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Cinética , Fígado/metabolismo , Fígado/patologia , Masculino , Simulação de Dinâmica Molecular , NAD/metabolismo , Oxirredução , Perfusão , Picloram/metabolismo , Ratos Wistar
5.
Nature ; 570(7759): 117-121, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31068692

RESUMO

Aneuploidy, which refers to unbalanced chromosome numbers, represents a class of genetic variation that is associated with cancer, birth defects and eukaryotic micro-organisms1-4. Whereas it is known that each aneuploid chromosome stoichiometry can give rise to a distinct pattern of gene expression and phenotypic profile4,5, it remains a fundamental question as to whether there are common cellular defects that are associated with aneuploidy. Here we show the existence in budding yeast of a common aneuploidy gene-expression signature that is suggestive of hypo-osmotic stress, using a strategy that enables the observation of common transcriptome changes of aneuploidy by averaging out karyotype-specific dosage effects in aneuploid yeast-cell populations with random and diverse chromosome stoichiometry. Consistently, aneuploid yeast exhibited increased plasma-membrane stress that led to impaired endocytosis, and this defect was also observed in aneuploid human cells. Thermodynamic modelling showed that hypo-osmotic-like stress is a general outcome of the proteome imbalance that is caused by aneuploidy, and also predicted a relationship between ploidy and cell size that was observed in yeast and aneuploid cancer cells. A genome-wide screen uncovered a general dependency of aneuploid cells on a pathway of ubiquitin-mediated endocytic recycling of nutrient transporters. Loss of this pathway, coupled with the endocytic defect inherent to aneuploidy, leads to a marked alteration of intracellular nutrient homeostasis.


Assuntos
Aneuploidia , Pressão Osmótica , Proteoma/genética , Proteoma/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Estresse Fisiológico , Membrana Celular/metabolismo , Membrana Celular/patologia , Proteínas de Ligação a DNA/metabolismo , Endocitose , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Homeostase , Humanos , Cariótipo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Termodinâmica , Fatores de Transcrição/metabolismo , Transcriptoma/genética , Ubiquitina/metabolismo , Complexos Ubiquitina-Proteína Ligase/metabolismo
6.
Discov Med ; 27(147): 111-117, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30939295

RESUMO

The classical molecular mechanism of thyroid hormone involves the intranuclear interaction of 3,5,3'-triiodo-L-thyronine (T3) with thyroid hormone-specific nuclear proteins and consequent specific gene expression. This mechanism prevails in normal cells. What we emphasize here is that how thyroid hormone acts depends upon the types of cell or cell-like structure, e.g., platelet, under consideration, and that cancer cells, dividing endothelial cells, phagocytes, and platelets respond to the liganding of L-thyroxine (T4) by plasma membrane integrin αvß3. In intact tumor cells, T4 at the integrin can modulate the transcription of a substantial number of specific genes relevant to cancer cell proliferation, cell metabolism, and cancer cell anti-apoptosis defense. T4 may also regulate the interactions of the integrin in the endothelial cell plasma membrane with adjacent vascular growth factor receptors, modulating angiogenesis. T4 activates platelets via αvß3 transferred from the megakaryocyte. It is also possible that, in addition to T4, reverse T3 (rT3) may have actions in cancer cells at the thyroid hormone receptor on αvß3.


Assuntos
Membrana Celular/metabolismo , Proliferação de Células , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Receptores dos Hormônios Tireóideos/metabolismo , Tiroxina/metabolismo , Animais , Membrana Celular/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Integrina alfaVbeta3/metabolismo , Neoplasias/patologia
7.
World J Surg Oncol ; 17(1): 64, 2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30967144

RESUMO

OBJECTIVE: To investigate the short- and long-term efficacy of membrane anatomy-guided laparoscopic spleen-preserving circumferential splenic hilar lymph node dissection for the treatment of advanced proximal gastric cancer. METHODS: A retrospective analysis was conducted in 186 patients with advanced proximal gastric cancer who underwent mesenteric anatomy-guided laparoscopic spleen-preserving splenic hilar lymph node dissection for advanced proximal gastric cancer in our center from March 2013 to March 2018. The patients were divided into two groups: one group was the laparoscopic anterior splenic hilar lymph node dissection group which we named L-ASHD, n = 103), while the other group was the laparoscopic circumferential splenic hilar lymph node dissection group which we named L-CSHD, n = 83). RESULTS: There was no significant difference in total operative time, intraoperative blood loss, postoperative length of hospital stay, and incidence of postoperative complications, etc. (P > 0.05). The number of harvested splenic hilar lymph nodes and the number of patients with harvested positive splenic hilar lymph nodes were both higher in the L-CSHD than in the L-ASHD (3.90 ± 2.52 vs. 3.02 ± 3.07, P < 0.05; 19 vs. 9 patients, P < 0.05). The positive rate of lymph nodes behind the splenic hilar was 8.4%. Kaplan-Meier survival curves showed that patients in the L-CSHD had similar OS and DFS compared with those of patients in the L-ASHD. CONCLUSION: Membrane anatomy-guided laparoscopic spleen-preserving circumferential splenic hilar lymph node dissection for advanced proximal gastric cancer is safe and feasible and can help avoid the incomplete dissection of positive lymph nodes.


Assuntos
Membrana Celular/patologia , Laparoscopia/métodos , Linfonodos/cirurgia , Tratamentos com Preservação do Órgão/métodos , Complicações Pós-Operatórias , Baço/cirurgia , Neoplasias Gástricas/cirurgia , Adolescente , Adulto , Idoso , Feminino , Seguimentos , Gastrectomia/métodos , Humanos , Excisão de Linfonodo/métodos , Linfonodos/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Baço/patologia , Neoplasias Gástricas/patologia , Taxa de Sobrevida , Adulto Jovem
8.
Microb Pathog ; 130: 71-80, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30844473

RESUMO

Mandacaru (Cereus jamacaru DC.), is a cactaceous symbol of caatinga vegetation at Brazilian Northeast region, however, there are no much studies about biochemical properties of this species. Here, the pioneering study brings very relevant data to highlight the importance of research with endemic plants of the caatinga. Afterward, the presence of enzymes such as peroxidase, protease, chitinase, ß-1,3-glucanase, and serine (trypsin) and cysteine (papain) protease inhibitors were evaluated. The peroxidase activity was higher in roots than other tissues. The ß-1,3-glucanase and proteolytic activity were prominent in stem and roots. The chitinase activity and protease inhibitor for both classes analyzed were detected in the stem and fruit peel. Antifungal activity against Colletotrichum gloeosporioides showed the root extract has a promising inhibitory activity on this economical important phytopathogenic fungus. After the contact of the hyphae with root extract increase in membrane permeability, based on Propidium Iodide (PI) uptake, and production of reactive oxygen species (ROS) were detected, compared to negative control. In addition, Scanning Electron Microscopy (SEM) analysis showed morphological damage on hyphae structure indicating that the treatment debilitates either cell membrane or cell wall leading to the cell death C. gloeosporioides.


Assuntos
Antifúngicos/farmacologia , Cactaceae/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/patologia , Colletotrichum/crescimento & desenvolvimento , Proteínas de Plantas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Antifúngicos/isolamento & purificação , Cactaceae/enzimologia , Colletotrichum/efeitos dos fármacos , Colletotrichum/enzimologia , Colletotrichum/ultraestrutura , Enzimas/análise , Frutas/química , Frutas/enzimologia , Hifas/ultraestrutura , Viabilidade Microbiana/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Permeabilidade/efeitos dos fármacos , Proteínas de Plantas/isolamento & purificação , Raízes de Plantas/química , Raízes de Plantas/enzimologia , Caules de Planta/química , Caules de Planta/enzimologia
9.
J Biol Chem ; 294(15): 6157-6171, 2019 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-30728247

RESUMO

A number of epilepsy-causing mutations have recently been identified in the genes of the α1, ß3, and γ2 subunits comprising the γ-aminobutyric acid type A (GABAA) receptor. These mutations are typically dominant, and in certain cases, such as the α1 and ß3 subunits, they may lead to a mix of receptors at the cell surface that contain no mutant subunits, a single mutated subunit, or two mutated subunits. To determine the effects of mutations in a single subunit or in two subunits on receptor activation, we created a concatenated protein assembly that links all five subunits of the α1ß3γ2 receptor and expresses them in the correct orientation. We created nine separate receptor variants with a single-mutant subunit and four receptors containing two subunits of the γ2R323Q, ß3D120N, ß3T157M, ß3Y302C, and ß3S254F epilepsy-causing mutations. We found that the singly mutated γ2R323Q subunit impairs GABA activation of the receptor by reducing GABA potency. A single ß3D120N, ß3T157M, or ß3Y302C mutation also substantially impaired receptor activation, and two copies of these mutants within a receptor were catastrophic. Of note, an effect of the ß3S254F mutation on GABA potency depended on the location of this mutant subunit within the receptor, possibly because of the membrane environment surrounding the transmembrane region of the receptor. Our results highlight that precise functional genomic analyses of GABAA receptor mutations using concatenated constructs can identify receptors with an intermediate phenotype that contribute to epileptic phenotypes and that are potential drug targets for precision medicine approaches.


Assuntos
Membrana Celular , Epilepsia , Mutação de Sentido Incorreto , Subunidades Proteicas , Receptores de GABA-A , Ácido gama-Aminobutírico/metabolismo , Substituição de Aminoácidos , Animais , Membrana Celular/genética , Membrana Celular/metabolismo , Membrana Celular/patologia , Epilepsia/genética , Epilepsia/metabolismo , Epilepsia/patologia , Humanos , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Receptores de GABA-A/genética , Receptores de GABA-A/metabolismo , Xenopus laevis
10.
Toxicology ; 414: 35-44, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30629986

RESUMO

Polyhexamethyleneguanidine phosphate (PHMG-P) is a polymeric biocide with a guanidine group. It has multiple positive charges in physiological conditions due to nitrogen atom in the guanidine and this cationic property contributes antimicrobial effect by disrupting cell membranes. To determine whether the cationic nature of PHMG-P results in cytotoxicity in human cell lines, anionic compounds were treated with PHMG-P. The cytotoxic effect was evaluated with ROS production and HMGB1 release into media. To verify the protection effect of anion against PHMG-P-induced cell death in vivo, a zebrafish assay was adopted. In addition, membrane disruption by PHMG-P was evaluated using fluorescein diacetate and propidium iodine staining. As a result, anionic substances such as DNA and poly-l-glutamic acids, decreased PHMG-P induced cell death in a dose-dependent manner. While HMGB1 and ROS production increased with PHMG-P concentration, the addition of anionic compounds with PHMG-P reduced the ROS production and HMGB1 release. The mortality of the zebrafish increased with PHMG-P concentration and co-treatment of anionic compounds with PHMG-P decreased mortality in a dose-dependent manner. In addition, FDA and PI staining confirmed that PHMG-P disrupts plasma membrane. Taken together, a cationic property is considered to be one of the main causes of PHMG-P-induced mammalian cell toxicity.


Assuntos
Membrana Celular/efeitos dos fármacos , Desinfetantes/toxicidade , Guanidinas/toxicidade , Células A549 , Animais , Membrana Celular/metabolismo , Membrana Celular/patologia , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Proteína HMGB1/metabolismo , Humanos , Interleucina-1beta/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Medição de Risco , Células THP-1 , Peixe-Zebra
11.
Neuron ; 101(4): 615-624.e5, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30686733

RESUMO

Axon loss determines persistent disability in multiple sclerosis patients. Here, we use in vivo calcium imaging in a multiple sclerosis model to show that cytoplasmic calcium levels determine the choice between axon loss and survival. We rule out the endoplasmic reticulum, glutamate excitotoxicity, and the reversal of the sodium-calcium exchanger as sources of intra-axonal calcium accumulation and instead identify nanoscale ruptures of the axonal plasma membrane as the critical path of calcium entry.


Assuntos
Axônios/metabolismo , Cálcio/metabolismo , Membrana Celular/patologia , Esclerose Múltipla/metabolismo , Animais , Axônios/patologia , Membrana Celular/metabolismo , Feminino , Transporte de Íons , Masculino , Camundongos , Esclerose Múltipla/etiologia
12.
Nanotechnology ; 30(18): 184004, 2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-30699387

RESUMO

The internalization kinetics resulting from magnetic nanoparticle interactions with tumor cells play an important role in nanoparticle-based cancer treatment efficiency. Here, the uptake kinetics of magnetoliposomes (ML) into human pancreatic tumor cells (MiaPaCa-2 and BxPC-3) are quantified using magnetic particle spectrometry. A comparison to the uptake kinetics for healthy L929 cells is given. The experimental results are used for the development of an uptake kinetics model describing the three relevant internalization processes: ML adsorption to the cell membrane, endo- and exocytosis. By fitting of experimental data, the rate constant of each internalization process is determined enabling the prediction of internalized ML at any incubation time. After seven hours incubation time, MiaPaCa-2 internalized three times more ML than BxPC-3 and L929 cells even though their ML adsorption rate constants were nearly the same. As the interaction of the ML with the cell membrane is non-specific, the uptake kinetics mirror the individual cell response to ML internalization. With a new mathematical term to cover the exocytosis contribution to the overall internalization process, the extended uptake kinetics model offers new possibilities to analyze the specific internalization mechanism for other nanoparticle and cell types.


Assuntos
Membrana Celular , Magnetismo , Modelos Biológicos , Nanopartículas/uso terapêutico , Neoplasias Pancreáticas , Animais , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Membrana Celular/patologia , Endocitose , Exocitose , Humanos , Cinética , Lipossomos , Camundongos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia
13.
Respir Physiol Neurobiol ; 261: 15-23, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30590202

RESUMO

Spinal chloride-dependent synaptic inhibition is critical in regulating breathing and requires neuronal chloride gradients established by cation-chloride cotransporters Na+-K+-2Cl- (NKCC1) and K+-Cl- (KCC2). Spinal transection disrupts NKCC1/KCC2 balance, diminishing chloride gradients in neurons below injury, contributing to spasticity and chronic pain. It is not known if similar disruptions in NKCC1/KCC2 balance occur in respiratory motor neurons after incomplete cervical contusion (C2SC). We hypothesized that C2SC disrupts NKCC1/KCC2 balance in phrenic motor neurons. NKCC1 and KCC2 immunoreactivity was assessed in CtB-positive phrenic motor neurons. Five weeks post-C2SC: 1) neither membrane-bound nor cytosolic NKCC1 expression were significantly changed, although the membrane/cytosolic ratio increased, consistent with net chloride influx; and 2) both membrane and cytosolic KCC2 expression increased, although the membrane/cytosolic ratio decreased, consistent with net chloride efflux. Thus, contrary to our original hypothesis, complex shifts in NKCC1/KCC2 balance occur post-C2SC. The functional significance of these changes remains unclear.


Assuntos
Medula Cervical/lesões , Contusões/metabolismo , Neurônios Motores/metabolismo , Nervo Frênico/metabolismo , Membro 2 da Família 12 de Carreador de Soluto/metabolismo , Simportadores/metabolismo , Animais , Membrana Celular/metabolismo , Membrana Celular/patologia , Medula Cervical/metabolismo , Medula Cervical/patologia , Vértebras Cervicais , Contusões/patologia , Citosol/metabolismo , Citosol/patologia , Modelos Animais de Doenças , Masculino , Neurônios Motores/patologia , Nervo Frênico/patologia , Distribuição Aleatória , Ratos Endogâmicos Lew , Traumatismos da Medula Espinal/metabolismo
14.
Nat Microbiol ; 4(2): 362-374, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30531979

RESUMO

Host recognition of microbial components is essential in mediating an effective immune response. Cytosolic bacteria must secure entry into the host cytoplasm to facilitate replication and, in doing so, liberate microbial ligands that activate cytosolic innate immune sensors and the inflammasome. Here, we identified a multicomponent enterotoxin, haemolysin BL (HBL), that engages activation of the inflammasome. This toxin is highly conserved among the human pathogen Bacillus cereus. The three subunits of HBL bind to the cell membrane in a linear order, forming a lytic pore and inducing activation of the NLRP3 inflammasome, secretion of interleukin-1ß and interleukin-18, and pyroptosis. Mechanistically, the HBL-induced pore results in the efflux of potassium and triggers the activation of the NLRP3 inflammasome. Furthermore, HBL-producing B. cereus induces rapid inflammasome-mediated mortality. Pharmacological inhibition of the NLRP3 inflammasome using MCC950 prevents B. cereus-induced lethality. Overall, our results reveal that cytosolic sensing of a toxin is central to the innate immune recognition of infection. Therapeutic modulation of this pathway enhances host protection against deadly bacterial infections.


Assuntos
Bacillus cereus/imunologia , Proteínas de Bactérias/imunologia , Enterotoxinas/imunologia , Proteínas Hemolisinas/imunologia , Inflamassomos/metabolismo , Inflamação , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Membrana Celular/metabolismo , Membrana Celular/patologia , Células Cultivadas , Meios de Cultivo Condicionados , Enterotoxinas/química , Enterotoxinas/metabolismo , Feminino , Proteínas Hemolisinas/metabolismo , Imunidade Inata , Macrófagos/imunologia , Macrófagos/patologia , Macrófagos/ultraestrutura , Masculino , Camundongos , Camundongos Mutantes , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Potássio/metabolismo , Multimerização Proteica , Piroptose , Análise de Sobrevida
15.
Front Immunol ; 9: 2753, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30555462

RESUMO

Inflammatory demyelinating CNS syndromes include, besides their most common entity multiple sclerosis (MS), several different diseases of either monophasic or recurrent character-including neuromyelitis optica spectrum disorders (NMOSDs) and acute disseminated encephalomyelitis (ADEM). Early diagnostic differentiation is crucial for devising individual treatment strategies. However, due to overlapping clinical and paraclinical features diagnosis at the first demyelinating event is not always possible. A multiplicity of potential biological markers that could discriminate the different diseases was studied. As the use of autoantibodies in patient management of other autoimmune diseases, is well-established and evidence for the critical involvement of B cells/antibodies in disease pathogenesis in inflammatory demyelinating CNS syndromes increases, antibodies seem to be valuable diagnostic tools. Since the detection of antibodies against aquaporin-4 (AQP-4), the understanding of immunopathogenesis and diagnostic management of NMOSDs has dramatically changed. However, for most inflammatory demyelinating CNS syndromes, a potential antigen target is still not known. A further extensively studied possible target structure is myelin oligodendrocyte glycoprotein (MOG), found at the outermost surface of myelin sheaths and oligodendrocyte membranes. With detection methods using cell-based assays with full-length, conformationally correct MOG, antibodies have been described in early studies with a subgroup of patients with ADEM. Recently, a humoral immune reaction against MOG has been found not only in monophasic diseases, but also in recurrent non-MS diseases, particularly in pediatric patients. This review presents the findings regarding MOG antibodies as potential biological markers in discriminating between these different demyelinating CNS diseases, and discusses recent developments, clinical implementations, and data on immunopathogenesis of MOG antibody-associated disorders.


Assuntos
Autoanticorpos/imunologia , Linfócitos B/imunologia , Encefalomielite Aguda Disseminada/imunologia , Glicoproteína Mielina-Oligodendrócito/imunologia , Neuromielite Óptica/imunologia , Animais , Aquaporina 4/imunologia , Linfócitos B/patologia , Membrana Celular/imunologia , Membrana Celular/patologia , Encefalomielite Aguda Disseminada/patologia , Humanos , Neuromielite Óptica/patologia , Oligodendroglia/imunologia , Oligodendroglia/patologia
16.
J. physiol. biochem ; 74(4): 531-538, nov. 2018. ilus, graf
Artigo em Inglês | IBECS | ID: ibc-179031

RESUMO

Squalene is the main unsaponifiable component of virgin olive oil, the main source of dietary fat in Mediterranean diet, traditionally associated with a less frequency of cardiovascular diseases. In this study, two experimental approaches were used. In the first, New Zealand rabbits fed for 4 weeks with a chow diet enriched in 1% sunflower oil for the control group, and in 1% of sunflower oil and 0.5% squalene for the squalene group. In the second, APOE KO mice received either Western diet or Western diet enriched in 0.5% squalene for 11 weeks. In both studies, liver samples were obtained and analyzed for their squalene content by gas chromatography-mass spectrometry. Hepatic distribution of squalene was also characterized in isolated subcellular organelles. Our results show that dietary squalene accumulates in the liver and a differential distribution according to studied model. In this regard, rabbits accumulated in cytoplasm within small size vesicles, whose size was not big enough to be considered lipid droplets, rough endoplasmic reticulum, and nuclear and plasma membranes. On the contrary, mice accumulated in large lipid droplets, and smooth reticulum fractions in addition to nuclear and plasma membranes. These results show that the squalene cellular localization may change according to experimental setting and be a starting point to characterize the mechanisms involved in the protective action of dietary squalene in several pathologies


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Assuntos
Animais , Masculino , Coelhos , Membrana Celular/metabolismo , Dieta Mediterrânea , Modelos Animais de Doenças , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Transporte Biológico , Membrana Celular/patologia , Vesículas Citoplasmáticas/metabolismo , Vesículas Citoplasmáticas/patologia , Citosol/metabolismo , Citosol/patologia , Fígado/patologia , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia
17.
ACS Appl Mater Interfaces ; 10(42): 35859-35868, 2018 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-30264566

RESUMO

Despite the importance of cell membranes for maintenance of integrity of cellular structures, there is still a lack of methods that allow simple real-time visualization of their damage. Herein, we describe gadolinium-Schiff base-doped quantum dots (GdQDs)-based probes for a fast facile spatial labeling of membrane injuries. We found that GdQDs preferentially interact through electron-rich and hydrophobic residues with a specific sequence motif of NHE-RF2 scaffold protein, exposed upon membrane damage. Such interaction results in a fast formation of intensively fluorescent droplets with a higher resolution and in a much shorter time compared to immunofluorescence using organic dye. GdQDs have high stability, brightness, and considerable cytocompatibility, which enable their use in long-term experiments in living cultures. To the best of our knowledge, this is the first report, demonstrating a method allowing real-time monitoring of membrane damage and recovery without any special requirements for instrumentation. Because of intensive brightness and simple signal pattern, GdQDs allow easy examination of interactions between cellular membranes and cell-penetrating peptides or cytostatic drugs. We anticipate that the simple and flexible method will also facilitate the studies dealing with host-pathogen interactions.


Assuntos
Membrana Celular/patologia , Gadolínio/química , Pontos Quânticos/química , Bases de Schiff/química , Sequência de Aminoácidos , Linhagem Celular Tumoral , Humanos , Modelos Moleculares , Peptídeos/química , Espectrometria de Fluorescência
18.
Int J Mol Sci ; 19(8)2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30071606

RESUMO

Cisplatin, carboplatin, and oxaliplatin are Pt-based drugs used in the chemotherapeutic eradication of cancer cells. Although most cancer patient cells initially respond well to the treatment, the clinical effectiveness declines over time as the cancer cells develop resistance to the drugs. The Pt-based drugs are accumulated via membrane-bound transporters, translocated to the nucleus, where they trigger various intracellular cell death programs through DNA interaction. Here we illustrate how resistance to Pt-based drugs, acquired through limitation in the activity/subcellular localization of canonical drug transporters, might be circumvented by the facilitated uptake of Pt-based drug complexes via nanocarriers/endocytosis or lipophilic drugs by diffusion.


Assuntos
Carboplatina/farmacocinética , Membrana Celular , Núcleo Celular , Cisplatino/farmacocinética , Neoplasias , Compostos Organoplatínicos/farmacocinética , Animais , Carboplatina/uso terapêutico , Membrana Celular/metabolismo , Membrana Celular/patologia , Núcleo Celular/metabolismo , Núcleo Celular/patologia , Cisplatino/uso terapêutico , DNA de Neoplasias/metabolismo , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Compostos Organoplatínicos/uso terapêutico , Oxaliplatina
19.
Proc Natl Acad Sci U S A ; 115(32): 8215-8220, 2018 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-30038012

RESUMO

We used the nanometer-wide tubules of the transverse tubular (t)-system of human skeletal muscle fibers as sensitive sensors for the quantitative monitoring of the Ca2+-handling properties in the narrow junctional cytoplasmic space sandwiched between the tubular membrane and the sarcoplasmic reticulum cisternae in single muscle fibers. The t-system sealed with a Ca2+-sensitive dye trapped in it is sensitive to changes in ryanodine receptor (RyR) Ca2+ leak, the store operated calcium entry flux, plasma membrane Ca pump, and sodium-calcium exchanger activities, thus making the sealed t-system a nanodomain Ca2+ sensor of Ca2+ dynamics in the junctional space. The sensor was used to assess the basal Ca2+-handling properties of human muscle fibers obtained by needle biopsy from control subjects and from people with a malignant hyperthermia (MH) causative RyR variant. Using this approach we show that the muscle fibers from MH-susceptible individuals display leakier RyRs and a greater capacity to extrude Ca2+ across the t-system membrane compared with fibers from controls. This study provides a quantitative way to assess the effect of RyR variants on junctional membrane Ca2+ handling under defined ionic conditions.


Assuntos
Cálcio/metabolismo , Junções Intercelulares/patologia , Hipertermia Maligna/patologia , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Retículo Sarcoplasmático/patologia , Adulto , Biópsia , Cálcio/química , Cátions Bivalentes/química , Cátions Bivalentes/metabolismo , Membrana Celular/metabolismo , Membrana Celular/patologia , Feminino , Corantes Fluorescentes/química , Humanos , Junções Intercelulares/metabolismo , Masculino , Hipertermia Maligna/genética , Mutação , Nanoestruturas/química , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Retículo Sarcoplasmático/metabolismo , Adulto Jovem
20.
Biomed Res Int ; 2018: 3465929, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29862265

RESUMO

Adducin (ADD) is a family of membrane skeleton proteins including ADD1, ADD2, and ADD3 that are encoded by distinct genes on different chromosomes. Adducin is primarily responsible for the assembly of spectrin-actin network that provides physical support to the plasma membrane and mediates signal transduction in various cellular physiological processes upon regulation by protein kinase C-dependent and calcium/calmodulin-dependent pathways. Abnormal phosphorylation, genetic variations, and alternative splicing of adducin may contribute to alterations in cellular functions involved in pathogenic processes. These alterations are associated with a wide range of diseases including cancer. This paper begins with a discussion on how adducin partakes in the structural formation of membrane skeleton, its regulation, and related functional characteristics, followed by a review on the pathogenesis of hypertension, biliary atresia, and cancer with respect to increased disease susceptibility mediated by adducin polymorphism and/or dysregulation. Given the functional diversity of adducin in different cellular compartments, we aim to provide a knowledge base whereby its pathophysiological roles can be better understood. More importantly, we aim to provide novel insights that may be of significance in turning the adducin model to clinical application.


Assuntos
Proteínas de Ligação a Calmodulina , Membrana Celular , Proteínas de Neoplasias , Neoplasias , Animais , Proteínas de Ligação a Calmodulina/genética , Proteínas de Ligação a Calmodulina/metabolismo , Membrana Celular/genética , Membrana Celular/metabolismo , Membrana Celular/patologia , Humanos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Polimorfismo Genético
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