RESUMO
Nuclear transport and vesicle trafficking are key cellular functions involved in the pathogenesis of RNA viruses. Among other pleiotropic effects on virus-infected host cells, ivermectin (IVM) inhibits nuclear transport mechanisms mediated by importins and atorvastatin (ATV) affects actin cytoskeleton-dependent trafficking controlled by Rho GTPases signaling. In this work, we first analyzed the response to infection in nasopharyngeal swabs from SARS-CoV-2-positive and -negative patients by assessing the gene expression of the respective host cell drug targets importins and Rho GTPases. COVID-19 patients showed alterations in KPNA3, KPNA5, KPNA7, KPNB1, RHOA, and CDC42 expression compared with non-COVID-19 patients. An in vitro model of infection with Poly(I:C), a synthetic analog of viral double-stranded RNA, triggered NF-κB activation, an effect that was halted by IVM and ATV treatment. Importin and Rho GTPases gene expression was also impaired by these drugs. Furthermore, through confocal microscopy, we analyzed the effects of IVM and ATV on nuclear to cytoplasmic importin α distribution, alone or in combination. Results showed a significant inhibition of importin α nuclear accumulation under IVM and ATV treatments. These findings confirm transcriptional alterations in importins and Rho GTPases upon SARS-CoV-2 infection and point to IVM and ATV as valid drugs to impair nuclear localization of importin α when used at clinically-relevant concentrations.
Assuntos
Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Atorvastatina/farmacologia , Tratamento Farmacológico da COVID-19 , Ivermectina/farmacologia , SARS-CoV-2/efeitos dos fármacos , alfa Carioferinas/metabolismo , Células A549 , Citoesqueleto de Actina/efeitos dos fármacos , Animais , Antivirais/farmacologia , Linhagem Celular Tumoral , Chlorocebus aethiops , Reposicionamento de Medicamentos , Células HeLa , Humanos , NF-kappa B/metabolismo , Células Vero , Proteínas rho de Ligação ao GTP/metabolismoRESUMO
The plant hormone cytokinin (CK) plays central roles in plant development and throughout plant life. The perception of CKs initiating their signaling cascade is mediated by histidine kinase receptors (AHKs). Traditionally thought to be perceived mostly at the endoplasmic reticulum (ER) due to receptor localization, CK was recently reported to be perceived at the plasma membrane (PM), with CK and its AHK receptors being trafficked between the PM and the ER. Some of the downstream mechanisms CK employs to regulate developmental processes are unknown. A seminal report in this field demonstrated that CK regulates auxin-mediated lateral root organogenesis by regulating the endocytic recycling of the auxin carrier PIN1, but since then, few works have addressed this issue. Modulation of the cellular cytoskeleton and trafficking could potentially be a mechanism executing responses downstream of CK signaling. We recently reported that CK affects the trafficking of the pattern recognition receptor LeEIX2, influencing the resultant defense output. We have also recently found that CK affects cellular trafficking and the actin cytoskeleton in fungi. In this work, we take an in-depth look at the effects of CK on cellular trafficking and on the actin cytoskeleton in plant cells. We find that CK influences the actin cytoskeleton and endomembrane compartments, both in the context of defense signaling-where CK acts to amplify the signal-as well as in steady state. We show that CK affects the distribution of FLS2, increasing its presence in the plasma membrane. Furthermore, CK enhances the cellular response to flg22, and flg22 sensing activates the CK response. Our results are in agreement with what we previously reported for fungi, suggesting a fundamental role for CK in regulating cellular integrity and trafficking as a mechanism for controlling and executing CK-mediated processes.
Assuntos
Citoesqueleto de Actina/metabolismo , Arabidopsis/imunologia , Citocininas/farmacologia , Citoesqueleto de Actina/efeitos dos fármacos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Transporte Biológico/efeitos dos fármacos , Endossomos/efeitos dos fármacos , Endossomos/metabolismo , Flagelina/farmacologia , Modelos Biológicos , Epiderme Vegetal/citologia , Imunidade Vegetal/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Receptores de Reconhecimento de Padrão/metabolismo , Nicotiana/metabolismoRESUMO
Cells exert traction forces on the extracellular matrix to which they are adhered through the formation of focal adhesions. Spatial-temporal regulation of traction forces is crucial in cell adhesion, migration, cellular division, and remodeling of the extracellular matrix. By cultivating cells on polyacrylamide hydrogels of different stiffness we were able to investigate the effects of substrate stiffness on the generation of cellular traction forces by Traction Force Microscopy (TFM), and characterize the molecular dynamics of the focal adhesion protein zyxin by Fluorescence Correlation Spectroscopy (FCS) and Fluorescence Recovery After Photobleaching (FRAP). As the rigidity of the substrate increases, we observed an increment of both, cellular traction generation and zyxin residence time at the focal adhesions, while its diffusion would not be altered. Moreover, we found a positive correlation between the traction forces exerted by cells and the residence time of zyxin at the substrate elasticities studied. We found that this correlation persists at the subcellular level, even if there is no variation in substrate stiffness, revealing that focal adhesions that exert greater traction present longer residence time for zyxin, i.e., zyxin protein has less probability to dissociate from the focal adhesion.
Assuntos
Estresse Mecânico , Zixina/química , Citoesqueleto de Actina/efeitos dos fármacos , Amidas/farmacologia , Animais , Bovinos , Adesão Celular , Citocalasina D/farmacologia , Células Endoteliais , Recuperação de Fluorescência Após Fotodegradação , Adesões Focais , Proteínas de Fluorescência Verde , Microscopia Intravital , Cinética , Lasers , Camundongos , Camundongos Endogâmicos BALB C , Piridinas/farmacologia , Proteínas Recombinantes de Fusão/química , Vinculina/química , Quinases Associadas a rho/antagonistas & inibidoresRESUMO
This work describes the synthesis of three new ruthenium(ii) complexes with gallic acid and derivatives of the general formula [Ru(L)(dppb)(bipy)]PF6, where L = gallate (GAC), benzoate (BAC), and esterified-gallate (EGA), bipy = 2,2'-bipyridine and dppb = 1,4-bis(diphenylphosphino)butane. The complexes were characterized by elemental analysis, molar conductivity, NMR, cyclic voltammetry, UV-vis and IR spectroscopy, and two of them by X-ray crystallography. Cell viability assays show promising results, indicating higher cytotoxicity of the complexes in MDA-MB-231 cells, a triple-negative breast cancer (TNBC) cell line, compared with the hormone-dependent MCF-7 cell line. Studies in vitro with the MDA-MB-231 cell line showed that only Ru(BAC) and Ru(GAC) interacted with BSA. Besides that, the Ru(GAC) complex, which has a polyphenolic acid, interacted in an apo-Tf structure and function dependent manner and it was able to inhibit the formation of reactive oxygen species. Ru(GAC) was able to cause damage to the cellular cytoskeleton leading to inhibition of some cellular processes of TNBC cells, such as invasion, migration, and adhesion.
Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Ácido Gálico/farmacologia , Piridinas/farmacologia , Rutênio/farmacologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Citoesqueleto de Actina/efeitos dos fármacos , Animais , Apoproteínas/metabolismo , Compostos de Bifenilo/química , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/química , Ácido Gálico/química , Humanos , Camundongos , Picratos/química , Piridinas/química , Rutênio/química , Soroalbumina Bovina/metabolismo , Transferrina/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
The ß-blocker propranolol (PROP) has been proposed as a repurposed treatment for breast cancer. The similarity of action between ß-agonists and antagonists found on breast cells encouraged us to compare PROP and isoproterenol (ISO, agonist) signaling pathways on a human breast cell line. Cell proliferation was measured by cell counting and DNA-synthesis. Cell adhesion was measured counting the cells that remained adhered to the plastic after different treatments. Changes in actin cytoskeleton were observed by fluorescence staining and Western Blot. ISO and PROP caused a diminution of cell proliferation and an increase of cell adhesion, reverted by the pure ß-antagonist ICI-118551. ISO and PROP induced a reorganization of actin cytoskeleton increasing F-actin, p-COFILIN and p-LIMK. While ISO elicited a marked enhancement of cAMP concentrations and an increase of vasodilator-stimulated phosphoprotein (VASP) and cAMP response element-binding protein (CREB) phosphorylation, PROP did not. Clathrin-mediated endocytosis inhibition or ß-arrestin1 dominant-negative mutant abrogated PROP-induced cell adhesion and COFILIN phosphorylation. The fact that PROP has been proposed as an adjuvant drug for breast cancer makes it necessary to determine the specific action of PROP in breast models. These results provide an explanation for the discrepancies observed between experimental results and clinical evidence.
Assuntos
Agonistas Adrenérgicos beta/farmacologia , Mama/citologia , Propranolol/farmacologia , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Fatores de Despolimerização de Actina/metabolismo , Actinas/metabolismo , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , AMP Cíclico/biossíntese , Feminino , Humanos , Isoproterenol/farmacologia , Quinases Lim/metabolismo , Estabilidade Proteica/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Fatores de TempoRESUMO
Fibrosis process in the liver is a clinical condition established in response to chronic lesions and may be reversible in many situations. In this process, hepatic stellate cells (HSCs) activate and produce extracellular matrix compounds. During fibrosis, the lipid metabolism is also altered and contributes to the transdifferentiation of the HSCs. Thus, controlling lipid metabolism in HSCs is suggested as a method to control or reverse the fibrotic condition. In the search for therapies that modulate lipid metabolism and treat liver diseases, silymarin has been identified as a relevant natural compound to treat liver pathologies. The present study aimed to evaluate the cellular and molecular effects of silymarin in the transdifferentiation process of HSCs (LX-2) from activated phenotype to a more quiesced-like cells , also focusing on understanding the modulatory effects of silymarin on lipid metabolism of HSCs. In our analyses, 100 µM of silymarin reduced the synthesis of actin filaments in activated cells, the synthesis of the protein level of α-SMA, and other pro-fibrotic factors such as CTGF and PFGF. The concentration of 150 µM silymarin did not reverse the activation aspects of LX-2 cells. However, both evaluated concentrations of the natural compound protected the cells from the negative effects of dimethyl sulfoxide (DMSO). Furthermore, we evaluated lipid-related molecules correlated to the transdifferentiation process of LX-2, and 100 µM of silymarin demonstrated to control molecules associated with lipid metabolism such as FASN, MLYCD, ACSL4, CPTs, among others. In contrast, cellular incubation with 150 µM of silymarin increased the synthesis of long-chain fatty acids and triglycerides, regarding the higher presence of DMSO (v/v) in the solvent. In conclusion, silymarin acts as a hepatoprotective agent and modulates the pro-fibrogenic stimuli of LX-2 cells, whose effects depend on stress levels in the cellular environment.
Assuntos
Transdiferenciação Celular/efeitos dos fármacos , Células Estreladas do Fígado/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Cirrose Hepática/metabolismo , Substâncias Protetoras/farmacologia , Silimarina/farmacologia , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Actinas/genética , Actinas/metabolismo , Linhagem Celular , Cromatografia Gasosa , Coenzima A Ligases/genética , Coenzima A Ligases/metabolismo , Fator de Crescimento do Tecido Conjuntivo/genética , Fator de Crescimento do Tecido Conjuntivo/metabolismo , Dimetil Sulfóxido/toxicidade , Ácido Graxo Sintase Tipo I/genética , Ácido Graxo Sintase Tipo I/metabolismo , Células Estreladas do Fígado/enzimologia , Células Estreladas do Fígado/metabolismo , Humanos , Fígado/metabolismo , Fígado/patologia , Cirrose Hepática/genética , Espectrometria de Massas , Triglicerídeos/metabolismoRESUMO
BACKGROUND/AIMS: Renal injury related to hypertension is characterized by glomerular and tubulointerstitial damage. The overactivation of the renin-angiotensin system mainly by angiotensin II (AII) seems to be a main contributor to progressive renal fibrosis. Epithelial to mesenchymal transition (EMT) is a mechanism that promotes renal fibrosis. Owing to heat shock protein 70 (Hsp70) cytoprotective properties, the chaperone exhibits an important potential as a therapeutic target. We investigate the role of Hsp70 on Angiotensin II induced epithelial mesenchymal transition within the Losartan effect in proximal tubule cells (PTCs) from a genetic model of hypertension in rats (SHR). METHODS: Primary cell culture of PTCs from SHR and Wistar Kyoto (WKY) rats were stimulated with AII, treated with Losartan (L), (L+AII) or untreated (Cc). The functional Hsp70 role in Losartan effect, after silencing its expression by cell transfection, was determined by Immunofluorescence; Western blotting; Gelatin Zymography assays; Scratch wound assays; flow cytometry; and Live Cell Time-lapse microscopy. RESULTS: (L) and (L+AII) treatments induced highly organized actin filaments and increased cortical actin in SHR PTCs. However, SHR PTCs (Cc) and (AII) treated cells showed disorganized actin. After Hsp72 knockdown in SHR PTCs, (L) was unable to stabilize the actin cytoskeleton. We demonstrated that (L) and (L+AII) increased E-cadherin levels and decreased vinculin, α-SMA, vimentin, pERK, p38 and Smad2-3 activation compared to (AII) and (Cc) SHR PTCs. Moreover, (L) inhibited MMP-2 and MMP-9 secretion, reduced migration and cellular displacement, stabilizing intercellular junctions. Notably, (L) treatment in shHsp72 knockdown SHR PTCs showed results similar to SHR PTCs (Cc). CONCLUSION: Our results demonstrate that Losartan through Hsp70 inhibits the EMT induced by AII in proximal tubule cells derived from SHR.
Assuntos
Angiotensina II/farmacologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/metabolismo , Losartan/farmacologia , Citoesqueleto de Actina/efeitos dos fármacos , Animais , Caderinas/metabolismo , Movimento Celular/efeitos dos fármacos , Células Cultivadas , Adesões Focais/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Proteínas de Choque Térmico HSP70/genética , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/metabolismo , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Vinculina/metabolismoRESUMO
Movement and phagocytosis are clue events in colonisation and invasion of tissues by Entamoeba histolytica, the protozoan causative of human amoebiasis. During phagocytosis, EhRab proteins interact with other functional molecules, conducting them to the precise cellular site. The gene encoding EhrabB is located in the complementary chain of the DNA fragment containing Ehcp112 and Ehadh genes, which encode for the proteins of the EhCPADH complex, involved in phagocytosis. This particular genetic organisation suggests that the three corresponding proteins may be functionally related. Here, we studied the relationship of EhRabB with EhCPADH and actin during phagocytosis. First, we obtained the EhRabB 3D structure to carry out docking analysis to predict the interaction sites involved in the EhRabB protein and the EhCPADH complex contact. By confocal microscopy, transmission electron microscopy, and immunoprecipitation assays, we revealed the interaction among these proteins when they move through different vesicles formed during phagocytosis. The role of the actin cytoskeleton in this event was also confirmed using Latrunculin A to interfere with actin polymerisation. This affected the movement of EhRabB and EhCPADH, as well as the rate of phagocytosis. Mutant trophozoites, silenced in EhrabB gene, evidenced the interaction of this molecule with EhCPADH and strengthened the role of actin during erythrophagocytosis.
Assuntos
Citoesqueleto de Actina/ultraestrutura , Entamoeba histolytica/metabolismo , Fagocitose/genética , Trofozoítos/ultraestrutura , Proteínas rab de Ligação ao GTP/química , Proteínas rab de Ligação ao GTP/metabolismo , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Actinas/ultraestrutura , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Entamoeba histolytica/genética , Entamoeba histolytica/patogenicidade , Entamoeba histolytica/ultraestrutura , Eritrócitos/parasitologia , Eritrócitos/ultraestrutura , Humanos , Microscopia Eletrônica de Transmissão , Simulação de Dinâmica Molecular , Mutação , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Trofozoítos/efeitos dos fármacos , Trofozoítos/metabolismo , Proteínas rab de Ligação ao GTP/genéticaRESUMO
Breast cancer is the most frequently diagnosed cancer among women worldwide. Here, recombinant human lactoferrin (rhLf) expressed in Pichia pastoris was tested for its potential cytotoxic activity on a panel of six human breast cancer cell lines. The rhLf cytotoxic effect was determined via a live-cell HTS imaging assay. Also, confocal microscopy and flow cytometry protocols were employed to investigate the rhLf mode of action. The rhLf revealed an effective CC50 of 91.4 and 109.46 µg/ml on non-metastatic and metastatic MDA-MB-231 cells, with favorable selective cytotoxicity index values, 11.68 and 13.99, respectively. Moreover, rhLf displayed satisfactory SCI values on four additional cell lines, MDA-MB-468, HCC70, MCF-7 and T-47D (1.55-3.34). Also, rhLf provoked plasma membrane blebbing, chromatin condensation and cell shrinkage in MDA-MB-231 cells, being all three apoptosis-related morphological changes. Also, rhLf was able to shrink the microfilaments, forming a punctuated cytoplasmic pattern in both the MDA-MB-231 and Hs-27 cells, as visualized in confocal photomicrographs. Moreover, performing flow cytometric analysis, rhLf provoked significant phosphatidylserine externalization, cell cycle arrest in the S phase and apoptosis-induced DNA fragmentation in MDA-MB-231 cells. Hence, rhLf possesses selective cytotoxicity on breast cancer cells. Also, rhLf caused apoptosis-associated morphologic changes, disruption of F-actin cytoskeleton organization, phosphatidylserine externalization, DNA fragmentation, and arrest of the cell cycle progression on triple-negative breast cancer MDA-MB-231 cells. Overall results suggest that rhLf is using the apoptosis pathway as its mechanism to inflict cell death. Findings warranty further evaluation of rhLf as a potential anti-breast cancer drug option.
Assuntos
Citoesqueleto de Actina/efeitos dos fármacos , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Lactoferrina/farmacologia , Neoplasias de Mama Triplo Negativas/patologia , Antineoplásicos/isolamento & purificação , Antineoplásicos/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fragmentação do DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Lactoferrina/genética , Lactoferrina/isolamento & purificação , Lactoferrina/metabolismo , Fosfatidilserinas/metabolismo , Pichia/genética , Pichia/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologiaRESUMO
Classâ 1 myosins (Myo1s) were the first unconventional myosins identified and humans have eight known Myo1 isoforms. The Myo1 family is involved in the regulation of gene expression, cytoskeletal rearrangements, delivery of proteins to the cell surface, cell migration and spreading. Thus, the important role of Myo1s in different biological processes is evident. In this study, we have investigated the effects of pentachloropseudilin (PClP), a reversible and allosteric potent inhibitor of Myo1s, on angiogenesis. We demonstrated that treatment of cells with PClP promoted a decrease in the number of vessels. The observed inhibition of angiogenesis is likely to be related to the inhibition of cell proliferation, migration and adhesion, as well as to alteration of the actin cytoskeleton pattern, as shown on a PClP-treated HUVEC cell line. Moreover, we also demonstrated that PClP treatment partially prevented the delivery of integrins to the plasma membrane. Finally, we showed that PClP caused DNA strand breaks, which are probably repaired during the cell cycle arrest in the G1 phase. Taken together, our results suggest that Myo1s participate directly in the angiogenesis process.