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1.
Anticancer Res ; 41(7): 3471-3480, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34230142

RESUMO

BACKGROUND/AIM: Pseudomonas exotoxin (PE) is one of the most widely used toxins in the construction of therapeutic fusion proteins in pre-clinical studies followed by phase trials. In principle, PE acts by blocking protein synthesis through catalyzing the inactivation of elongation factor-2 (EF-2). The interleukin-13 fused PE (IL13-PE) cytotoxin was previously designed to target GBM cells. In this study, the cytotoxic effects of IL13-PE were evaluated in 5 different types of cancers and the therapeutic effects were further analyzed in a lung cancer cell line, NCI-H460. Conceptually, in another lung cancer cell line (A549), IL13Rα2 was overexpressed by lentiviruses (A549-IL13Rα2) and evaluated for cytotoxic efficacy of IL13-PE. MATERIALS AND METHODS: The expression profile of IL13Rα2 in different cancer cell lines was determined by RT-PCR. Secretable toxin fusion was expressed in the toxin resistant HEK-293T cell line (293T-TxR) by using a plasmid coding for IL13-PE and IRES-GFP (LV-IL13-PE-IRES/GFP). Next, the cells were shown to produce and secrete functional IL13-PE by dot blot analysis, followed by cell viability assays and cell death analysis. RESULTS: Upon treatment with IL13-PE, a significant decrease in cell viability was selectively demonstrated in cancer cells with cognate receptor expression. IL13-PE treatment increased the apoptotic/necrotic cell populations in the NCI-H460 cell line. CONCLUSION: Our results demonstrate that IL13-PE can be a therapeutic target for tumors bearing mostly IL13Rα2 positive cell populations. Our findings also suggest a cell-based delivery option for the recombinant toxins in the treatment of different cancers which can provide a solution for the clinical use of toxin therapy.


Assuntos
Exotoxinas/farmacologia , Imunotoxinas/farmacologia , Neoplasias/tratamento farmacológico , Pseudomonas/metabolismo , Células A549 , Antineoplásicos/farmacologia , Linhagem Celular , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Células HEK293 , Humanos , Interleucina-13/metabolismo , Neoplasias/metabolismo , Proteínas Recombinantes de Fusão/farmacologia
2.
Int J Mol Sci ; 22(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204256

RESUMO

The marine carotenoids fucoxanthin and siphonaxanthin are powerful antioxidants that are attracting focused attention to identify a variety of health benefits and industry applications. In this study, the binding energy of these carotenoids with the SARS-CoV-2 Spike-glycoprotein was predicted by molecular docking simulation, and their inhibitory activity was confirmed with SARS-CoV-2 pseudovirus on HEK293 cells overexpressing angiotensin-converting enzyme 2 (ACE2). Siphonaxanthin from Codium fragile showed significant antiviral activity with an IC50 of 87.4 µM against SARS-CoV-2 pseudovirus entry, while fucoxanthin from Undaria pinnatifida sporophyll did not. The acute toxicities were predicted to be relatively low, and pharmacokinetic predictions indicate GI absorption. Although further studies are needed to elucidate the inhibition of viral infection by siphonaxanthin, these results provide useful information in the application of these marine carotenoids for the treatment and prevention of COVID-19.


Assuntos
Antivirais/farmacologia , SARS-CoV-2/fisiologia , Internalização do Vírus/efeitos dos fármacos , Xantofilas/química , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Antivirais/química , Antivirais/uso terapêutico , Sítios de Ligação , COVID-19/tratamento farmacológico , COVID-19/patologia , COVID-19/virologia , Sobrevivência Celular/efeitos dos fármacos , Clorófitas/química , Clorófitas/metabolismo , Células HEK293 , Meia-Vida , Humanos , Simulação de Acoplamento Molecular , Feófitas/química , Feófitas/metabolismo , Ratos , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Xantofilas/metabolismo , Xantofilas/farmacologia , Xantofilas/uso terapêutico
3.
Int J Mol Sci ; 22(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204305

RESUMO

The SARS-CoV-2 Spike glycoprotein (S protein) acquired a unique new 4 amino acid -PRRA- insertion sequence at amino acid residues (aa) 681-684 that forms a new furin cleavage site in S protein as well as several new glycosylation sites. We studied various statistical properties of the -PRRA- insertion at the RNA level (CCUCGGCGGGCA). The nucleotide composition and codon usage of this sequence are different from the rest of the SARS-CoV-2 genome. One of such features is two tandem CGG codons, although the CGG codon is the rarest codon in the SARS-CoV-2 genome. This suggests that the insertion sequence could cause ribosome pausing as the result of these rare codons. Due to population variants, the Nextstrain divergence measure of the CCU codon is extremely large. We cannot exclude that this divergence might affect host immune responses/effectiveness of SARS-CoV-2 vaccines, possibilities awaiting further investigation. Our experimental studies show that the expression level of original RNA sequence "wildtype" spike protein is much lower than for codon-optimized spike protein in all studied cell lines. Interestingly, the original spike sequence produces a higher titer of pseudoviral particles and a higher level of infection. Further mutagenesis experiments suggest that this dual-effect insert, comprised of a combination of overlapping translation pausing and furin sites, has allowed SARS-CoV-2 to infect its new host (human) more readily. This underlines the importance of ribosome pausing to allow efficient regulation of protein expression and also of cotranslational subdomain folding.


Assuntos
RNA Viral/metabolismo , Ribossomos/metabolismo , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/genética , Animais , Sequência de Bases , Células COS , COVID-19/patologia , COVID-19/virologia , Chlorocebus aethiops , Uso do Códon , Células HEK293 , Humanos , Mutagênese , SARS-CoV-2/isolamento & purificação , Alinhamento de Sequência , Glicoproteína da Espícula de Coronavírus/metabolismo
4.
Mater Sci Eng C Mater Biol Appl ; 127: 112184, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225845

RESUMO

Polyethyleneimine (PEI) polymers are known to compact DNA strands into spheroid, toroid, or rod structures. A formulation with mannose-grafted PEI (PEIm), however, was reported to compact DNA into ~100 nm spheroids that indented like thin-walled pressurized shells. The goal of the study is to understand why mannose bristles divert the traditional pathway of PEI-DNA compaction to produce shell-like structures, and to manipulate the process so that proteins can be packed into the core of the assembling shells for co-delivering DNA and proteins into cells. DLS, AFM, and TEM imaging provide a consistent picture that BSA proteins can be packed into the shells without altering the shell architecture, as long as the proteins were added during the time course of shell assembly. Force spectroscopy studies reveal that DNA shells that buckle also have a rich surface-coating of mannose, indicating that a micelle-like partitioning of hydrophobic and hydrophilic layers governs shell assembly. When HEK293T cells are spiked with BSA-laden DNA shells, co-transfection of DNA and BSA is observed at higher levels than control formulations. Distinct micron-sized features appear having both green fluorescence from BSA-FITC and blue fluorescence from NucBlue DNA stain, suggesting BSA release in nucleus and secretory granules. With DNA nanocontainers, proteins can take advantage of the efficiency of PEI-based DNA transfection for hitchhiking into cells while being shielded from the challenges of the intracellular route. DNA nanocontainers are rapid to assemble, not dependent on the DNA sequence, and can be adapted for different protein types; thereby having potential to serve as a high-throughput platform in scenarios where DNA and protein have to be released at the same site and time within cells (e.g., theranostics, multiplexed co-delivery, gene editing).


Assuntos
DNA , Polietilenoimina , Células HEK293 , Humanos , Micelas , Polímeros , Transfecção
5.
Cells ; 10(6)2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34200372

RESUMO

Coronaviruses such as SARS-CoV-2, which is responsible for COVID-19, depend on virus spike protein binding to host cell receptors to cause infection. The SARS-CoV-2 spike protein binds primarily to ACE2 on target cells and is then processed by membrane proteases, including TMPRSS2, leading to viral internalisation or fusion with the plasma membrane. It has been suggested, however, that receptors other than ACE2 may be involved in virus binding. We have investigated the interactions of recombinant versions of the spike protein with human epithelial cell lines that express low/very low levels of ACE2 and TMPRSS2 in a proxy assay for interaction with host cells. A tagged form of the spike protein containing the S1 and S2 regions bound in a temperature-dependent manner to all cell lines, whereas the S1 region alone and the receptor-binding domain (RBD) interacted only weakly. Spike protein associated with cells independently of ACE2 and TMPRSS2, while RBD required the presence of high levels of ACE2 for interaction. As the spike protein has previously been shown to bind heparin, a soluble glycosaminoglycan, we tested the effects of various heparins on ACE2-independent spike protein interaction with cells. Unfractionated heparin inhibited spike protein interaction with an IC50 value of <0.05 U/mL, whereas two low-molecular-weight heparins were less effective. A mutant form of the spike protein, lacking the arginine-rich putative furin cleavage site, interacted only weakly with cells and had a lower affinity for unfractionated and low-molecular-weight heparin than the wild-type spike protein. This suggests that the furin cleavage site might also be a heparin-binding site and potentially important for interactions with host cells. The glycosaminoglycans heparan sulphate and dermatan sulphate, but not chondroitin sulphate, also inhibited the binding of spike protein, indicating that it might bind to one or both of these glycosaminoglycans on the surface of target cells.


Assuntos
Enzima de Conversão de Angiotensina 2/fisiologia , Células Epiteliais/metabolismo , Heparina/farmacologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Células A549 , Enzima de Conversão de Angiotensina 2/genética , Animais , Sítios de Ligação/efeitos dos fármacos , Sítios de Ligação/genética , Células CACO-2 , Linhagem Celular , Chlorocebus aethiops , Dermatan Sulfato/farmacologia , Regulação para Baixo/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/virologia , Glicosaminoglicanos/farmacologia , Células HEK293 , Células HaCaT , Heparitina Sulfato/farmacologia , Humanos , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/genética , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/fisiologia , Glicoproteína da Espícula de Coronavírus/química , Células Vero , Internalização do Vírus/efeitos dos fármacos
6.
Int J Mol Sci ; 22(12)2021 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-34199295

RESUMO

Spinocerebellar ataxia type 3 (SCA3), a hereditary and lethal neurodegenerative disease, is attributed to the abnormal accumulation of undegradable polyglutamine (polyQ), which is encoded by mutated ataxin-3 gene (ATXN3). The toxic fragments processed from mutant ATXN3 can induce neuronal death, leading to the muscular incoordination of the human body. Some treatment strategies of SCA3 are preferentially focused on depleting the abnormal aggregates, which led to the discovery of small molecule n-butylidenephthalide (n-BP). n-BP-promoted autophagy protected the loss of Purkinje cell in the cerebellum that regulates the network associated with motor functions. We report that the n-BP treatment may be effective in treating SCA3 disease. n-BP treatment led to the depletion of mutant ATXN3 with the expanded polyQ chain and the toxic fragments resulting in increased metabolic activity and alleviated atrophy of SCA3 murine cerebellum. Furthermore, n-BP treated animal and HEK-293GFP-ATXN3-84Q cell models could consistently show the depletion of aggregates through mTOR inhibition. With its unique mechanism, the two autophagic inhibitors Bafilomycin A1 and wortmannin could halt the n-BP-induced elimination of aggregates. Collectively, n-BP shows promising results for the treatment of SCA3.


Assuntos
Autofagia , Doença de Machado-Joseph/tratamento farmacológico , Doença de Machado-Joseph/patologia , Anidridos Ftálicos/uso terapêutico , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Adenilato Quinase/metabolismo , Animais , Ataxina-3/genética , Autofagia/efeitos dos fármacos , Cerebelo/patologia , Feminino , Células HEK293 , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Doença de Machado-Joseph/fisiopatologia , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Mutação/genética , Anidridos Ftálicos/farmacologia , Agregados Proteicos/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células de Purkinje/efeitos dos fármacos , Células de Purkinje/patologia , Transdução de Sinais/efeitos dos fármacos
7.
Int J Mol Sci ; 22(12)2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34203807

RESUMO

Genome editing using CRISPR-Cas9 nucleases is based on the repair of the DNA double-strand break (DSB). In eukaryotic cells, DSBs are rejoined through homology-directed repair (HDR), non-homologous end joining (NHEJ) or microhomology-mediated end joining (MMEJ) pathways. Among these, it is thought that the NHEJ pathway is dominant and occurs throughout a cell cycle. NHEJ-based DSB repair is known to be error-prone; however, there are few studies that delve into it deeply in endogenous genes. Here, we quantify the degree of NHEJ-based DSB repair accuracy (termed NHEJ accuracy) in human-originated cells by incorporating exogenous DNA oligonucleotides. Through an analysis of joined sequences between the exogenous DNA and the endogenous target after DSBs occur, we determined that the average value of NHEJ accuracy is approximately 75% in maximum in HEK 293T cells. In a deep analysis, we found that NHEJ accuracy is sequence-dependent and the value at the DSB end proximal to a protospacer adjacent motif (PAM) is relatively lower than that at the DSB end distal to the PAM. In addition, we observed a negative correlation between the insertion mutation ratio and the degree of NHEJ accuracy. Our findings would broaden the understanding of Cas9-mediated genome editing.


Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Clivagem do DNA , Reparo do DNA por Junção de Extremidades/genética , Sequência de Bases , DNA/metabolismo , Células HEK293 , Células HeLa , Humanos , Mutação/genética , Oligonucleotídeos/metabolismo , RNA Guia/genética , Deleção de Sequência/genética
8.
Int J Mol Sci ; 22(12)2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34203920

RESUMO

The negatively charged Asp325 residue has proved to be essential for iron export by human (HsFPN1) and primate Philippine tarsier (TsFpn) ferroportin, but its exact role during the iron transport cycle is still to be elucidated. It has been posited as being functionally equivalent to the metal ion-coordinating residue His261 in the C-lobe of the bacterial homolog BbFpn, but the two residues arise in different sequence motifs of the discontinuous TM7 transmembrane helix. Furthermore, BbFpn is not subject to extracellular regulation, contrary to its mammalian orthologues which are downregulated by hepcidin. To get further insight into the molecular mechanisms related to iron export in mammals in which Asp325 is involved, we investigated the behavior of the Asp325Ala, Asp325His, and Asp325Asn mutants in transiently transfected HEK293T cells, and performed a comparative structural analysis. Our biochemical studies clearly distinguished between the Asp325Ala and Asp325His mutants, which result in a dramatic decrease in plasma membrane expression of FPN1, and the Asp325Asn mutant, which alters iron egress without affecting protein localization. Analysis of the 3D structures of HsFPN1 and TsFpn in the outward-facing (OF) state indicated that Asp325 does not interact directly with metal ions but is involved in the modulation of Cys326 metal-binding capacity. Moreover, models of the architecture of mammalian proteins in the inward-facing (IF) state suggested that Asp325 may form an inter-lobe salt-bridge with Arg40 (TM1) when not interacting with Cys326. These findings allow to suggest that Asp325 may be important for fine-tuning iron recognition in the C-lobe, as well as for local structural changes during the IF-to-OF transition at the extracellular gate level. Inability to form a salt-bridge between TM1 and TM7b during iron translocation could lead to protein instability, as shown by the Asp325Ala and Asp325His mutants.


Assuntos
Ácido Aspártico/metabolismo , Proteínas de Transporte de Cátions/química , Proteínas de Transporte de Cátions/metabolismo , Sítios de Ligação , Transporte Biológico , Membrana Celular/metabolismo , Células HEK293 , Humanos , Ferro/metabolismo , Estrutura Secundária de Proteína , Relação Estrutura-Atividade
9.
Molecules ; 26(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204457

RESUMO

Mitragyna speciosa Korth (kratom) is known for its psychoactive and analgesic properties. Mitragynine is the primary constituent present in kratom leaves. This study highlights the utilisation of the green accelerated solvent extraction technique to produce a better, non-toxic and antinociceptive active botanical extract of kratom. ASE M. speciosa extract had a dry yield (0.53-2.91 g) and showed a constant mitragynine content (6.53-7.19%) when extracted with organic solvents of different polarities. It only requires a shorter extraction time (5 min) and a reduced amount of solvents (less than 100 mL). A substantial amount of total phenolic (407.83 ± 2.50 GAE mg/g and flavonoids (194.00 ± 5.00 QE mg/g) were found in ASE kratom ethanol extract. The MTT test indicated that the ASE kratom ethanolic leaf extract is non-cytotoxic towards HEK-293 and HeLa Chang liver cells. In mice, ASE kratom ethanolic extract (200 mg/kg) demonstrated a better antinociceptive effect compared to methanol and ethyl acetate leaf extracts. The presence of bioactive indole alkaloids and flavonols such as mitragynine, paynantheine, quercetin, and rutin in ASE kratom ethanolic leaf extract was detected using UHPLC-ESI-QTOF-MS/MS analysis supports its antinociceptive properties. ASE ethanolic leaf extract offers a better, safe, and cost-effective choice of test botanical extract for further preclinical studies.


Assuntos
Mitragyna/química , Extratos Vegetais/química , Alcaloides de Triptamina e Secologanina/isolamento & purificação , Animais , Células HEK293 , Células HeLa , Humanos , Masculino , Camundongos , Mitragyna/metabolismo , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Alcaloides de Triptamina e Secologanina/química , Solventes/química
10.
Molecules ; 26(12)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207340

RESUMO

Mass spectrometry (MS) used in proteomic approaches is able to detect hundreds of proteins in a single assay. Although undeniable high analytical power of MS, data acquired sometimes lead to confusing results, especially during a search of very selective, unique interactions in complex biological matrices. Here, we would like to show an example of such confusing data, providing an extensive discussion on the observed phenomenon. Our investigations focus on the interaction between the Zika virus NS3 protease, which is essential for virus replication. This enzyme is known for helping to remodel the microenvironment of the infected cells. Several reports show that this protease can process cellular substrates and thereby modify cellular pathways that are important for the virus. Herein, we explored some of the targets of NS3, clearly shown by proteomic techniques, as processed during infection. Unfortunately, we could not confirm the biological relevance of protein targets for viral infections detected by MS. Thus, although mass spectrometry is highly sensitive and useful in many instances, also being able to show directions where cell/virus interaction occurs, we believe that deep recognition of their biological role is essential to receive complete insight into the investigated process.


Assuntos
Espectrometria de Massas/métodos , Serina Endopeptidases/metabolismo , Proteínas não Estruturais Virais/metabolismo , Proteínas Virais/metabolismo , Infecção por Zika virus/virologia , Zika virus/metabolismo , Células A549 , Animais , Linhagem Celular , Linhagem Celular Tumoral , Microambiente Celular/fisiologia , Chlorocebus aethiops , Células HEK293 , Humanos , Proteômica/métodos , Transdução de Sinais/fisiologia , Células Vero
11.
Int J Mol Sci ; 22(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: covidwho-1273459

RESUMO

The SARS-CoV-2 Spike glycoprotein (S protein) acquired a unique new 4 amino acid -PRRA- insertion sequence at amino acid residues (aa) 681-684 that forms a new furin cleavage site in S protein as well as several new glycosylation sites. We studied various statistical properties of the -PRRA- insertion at the RNA level (CCUCGGCGGGCA). The nucleotide composition and codon usage of this sequence are different from the rest of the SARS-CoV-2 genome. One of such features is two tandem CGG codons, although the CGG codon is the rarest codon in the SARS-CoV-2 genome. This suggests that the insertion sequence could cause ribosome pausing as the result of these rare codons. Due to population variants, the Nextstrain divergence measure of the CCU codon is extremely large. We cannot exclude that this divergence might affect host immune responses/effectiveness of SARS-CoV-2 vaccines, possibilities awaiting further investigation. Our experimental studies show that the expression level of original RNA sequence "wildtype" spike protein is much lower than for codon-optimized spike protein in all studied cell lines. Interestingly, the original spike sequence produces a higher titer of pseudoviral particles and a higher level of infection. Further mutagenesis experiments suggest that this dual-effect insert, comprised of a combination of overlapping translation pausing and furin sites, has allowed SARS-CoV-2 to infect its new host (human) more readily. This underlines the importance of ribosome pausing to allow efficient regulation of protein expression and also of cotranslational subdomain folding.


Assuntos
RNA Viral/metabolismo , Ribossomos/metabolismo , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/genética , Animais , Sequência de Bases , Células COS , COVID-19/patologia , COVID-19/virologia , Chlorocebus aethiops , Uso do Códon , Células HEK293 , Humanos , Mutagênese , SARS-CoV-2/isolamento & purificação , Alinhamento de Sequência , Glicoproteína da Espícula de Coronavírus/metabolismo
12.
Int J Mol Sci ; 22(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: covidwho-1273458

RESUMO

The marine carotenoids fucoxanthin and siphonaxanthin are powerful antioxidants that are attracting focused attention to identify a variety of health benefits and industry applications. In this study, the binding energy of these carotenoids with the SARS-CoV-2 Spike-glycoprotein was predicted by molecular docking simulation, and their inhibitory activity was confirmed with SARS-CoV-2 pseudovirus on HEK293 cells overexpressing angiotensin-converting enzyme 2 (ACE2). Siphonaxanthin from Codium fragile showed significant antiviral activity with an IC50 of 87.4 µM against SARS-CoV-2 pseudovirus entry, while fucoxanthin from Undaria pinnatifida sporophyll did not. The acute toxicities were predicted to be relatively low, and pharmacokinetic predictions indicate GI absorption. Although further studies are needed to elucidate the inhibition of viral infection by siphonaxanthin, these results provide useful information in the application of these marine carotenoids for the treatment and prevention of COVID-19.


Assuntos
Antivirais/farmacologia , SARS-CoV-2/fisiologia , Internalização do Vírus/efeitos dos fármacos , Xantofilas/química , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Antivirais/química , Antivirais/uso terapêutico , Sítios de Ligação , COVID-19/tratamento farmacológico , COVID-19/patologia , COVID-19/virologia , Sobrevivência Celular/efeitos dos fármacos , Clorófitas/química , Clorófitas/metabolismo , Células HEK293 , Meia-Vida , Humanos , Simulação de Acoplamento Molecular , Feófitas/química , Feófitas/metabolismo , Ratos , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Xantofilas/metabolismo , Xantofilas/farmacologia , Xantofilas/uso terapêutico
13.
Cells ; 10(6)2021 06 07.
Artigo em Inglês | MEDLINE | ID: covidwho-1259431

RESUMO

Coronaviruses such as SARS-CoV-2, which is responsible for COVID-19, depend on virus spike protein binding to host cell receptors to cause infection. The SARS-CoV-2 spike protein binds primarily to ACE2 on target cells and is then processed by membrane proteases, including TMPRSS2, leading to viral internalisation or fusion with the plasma membrane. It has been suggested, however, that receptors other than ACE2 may be involved in virus binding. We have investigated the interactions of recombinant versions of the spike protein with human epithelial cell lines that express low/very low levels of ACE2 and TMPRSS2 in a proxy assay for interaction with host cells. A tagged form of the spike protein containing the S1 and S2 regions bound in a temperature-dependent manner to all cell lines, whereas the S1 region alone and the receptor-binding domain (RBD) interacted only weakly. Spike protein associated with cells independently of ACE2 and TMPRSS2, while RBD required the presence of high levels of ACE2 for interaction. As the spike protein has previously been shown to bind heparin, a soluble glycosaminoglycan, we tested the effects of various heparins on ACE2-independent spike protein interaction with cells. Unfractionated heparin inhibited spike protein interaction with an IC50 value of <0.05 U/mL, whereas two low-molecular-weight heparins were less effective. A mutant form of the spike protein, lacking the arginine-rich putative furin cleavage site, interacted only weakly with cells and had a lower affinity for unfractionated and low-molecular-weight heparin than the wild-type spike protein. This suggests that the furin cleavage site might also be a heparin-binding site and potentially important for interactions with host cells. The glycosaminoglycans heparan sulphate and dermatan sulphate, but not chondroitin sulphate, also inhibited the binding of spike protein, indicating that it might bind to one or both of these glycosaminoglycans on the surface of target cells.


Assuntos
Enzima de Conversão de Angiotensina 2/fisiologia , Células Epiteliais/metabolismo , Heparina/farmacologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Células A549 , Enzima de Conversão de Angiotensina 2/genética , Animais , Sítios de Ligação/efeitos dos fármacos , Sítios de Ligação/genética , Células CACO-2 , Linhagem Celular , Chlorocebus aethiops , Dermatan Sulfato/farmacologia , Regulação para Baixo/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/virologia , Glicosaminoglicanos/farmacologia , Células HEK293 , Células HaCaT , Heparitina Sulfato/farmacologia , Humanos , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/genética , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/fisiologia , Glicoproteína da Espícula de Coronavírus/química , Células Vero , Internalização do Vírus/efeitos dos fármacos
14.
Molecules ; 26(11)2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34206005

RESUMO

Phenanthroindolizidines, such as antofine and tylophorine, are a family of natural alkaloids isolated from different species of Asclepiadaceas. They are characterized by interesting biological activities, such as pronounced cytotoxicity against different human cancerous cell lines, including multidrug-resistant examples. Nonetheless, these derivatives are associated with severe neurotoxicity and loss of in vivo activity due to the highly lipophilic nature of the alkaloids. Here, we describe the development of highly polar prodrugs of antofine and tylophorine as hypoxia-targeted prodrugs. The developed quaternary ammonium salts of phenanthroindolizidines showed high chemical and metabolic stability and are predicted to have no penetration through the blood-brain barrier. The designed prodrugs displayed decreased cytotoxicity when tested under normoxic conditions. However, their cytotoxic activity considerably increased when tested under hypoxic conditions.


Assuntos
Alcaloides/química , Antineoplásicos/síntese química , Indóis/química , Indolizinas/química , Fenantrenos/química , Fenantrolinas/química , Pró-Fármacos/síntese química , Compostos de Amônio Quaternário/síntese química , Compostos de Amônio Quaternário/farmacologia , Hipóxia Tumoral/efeitos dos fármacos , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Células CHO , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cricetulus , Ensaios de Seleção de Medicamentos Antitumorais , Células HEK293 , Humanos , Células MCF-7 , Estrutura Molecular , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Compostos de Amônio Quaternário/química , Relação Estrutura-Atividade
15.
Int J Mol Sci ; 22(13)2021 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-34206968

RESUMO

The search for and analysis of new ligands for innate immunity receptors are of special significance for understanding the regulatory mechanisms of immune response. Here we show that the major heat shock protein 70 (Hsp70) can bind to and activate TREM-1, the innate immunity receptor expressed on monocytes. The Hsp70-TREM-1 interaction activates expression of TNFα and IFNγ mRNAs in monocytes and stimulates IL-2 secretion by PBMCs. Moreover, incubation of PBMCs with Hsp70 leads to an appearance of cytotoxic lymphocyte subpopulations active against the MHC-negative tumor cells. In addition, both the CD4+ T-lymphocytes and CD14+ monocytes are necessary for the Hsp70 signal transduction and a consequent activation of the cytotoxic lymphocytes. We believe that data presented in this study will broaden the views on the involvement of Hsp70 in the antitumor immunity.


Assuntos
Proteínas de Choque Térmico HSP70/metabolismo , Neoplasias/metabolismo , Receptor Gatilho 1 Expresso em Células Mieloides/metabolismo , Células HEK293 , Antígenos HLA/genética , Antígenos HLA/metabolismo , Células HeLa , Humanos , Interferon gama/metabolismo , Células K562 , Monócitos/metabolismo , Linfócitos T Citotóxicos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
16.
Curr Protoc ; 1(7): e190, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34260831

RESUMO

Protein-protein interactions (PPIs) are ubiquitously involved in cellular processes such as gene expression, enzymatic catalysis, and signal transduction. To study dynamic PPIs, real-time methods such as Förster resonance energy transfer and bioluminescence resonance energy transfer can provide high temporal resolution, but they only allow PPI detection in a limited area at a time and do not permit post-PPI analysis or manipulation of the cells. Integration methods such as the yeast two-hybrid system and split protein systems integrate PPI signals over time and allow subsequent analysis, but they lose information on dynamics. To address some of these limitations, an assay named SPARK (Specific Protein Association tool giving transcriptional Readout with rapid Kinetics) has recently been published. Similar to many existing integrators, SPARK converts PPIs into a transcriptional signal. SPARK, however, also adds blue light as a co-stimulus to achieve temporal gating; SPARK only records PPIs during light stimulation. Here, we describe the procedures for using SPARK assays to study a dynamic PPI of interest, including designing DNA constructs and optimization in HEK293T/17 cell cultures. These protocols are generally applicable to various PPI partners and can be used in different biological contexts. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Designing DNA constructs for SPARK Basic Protocol 2: Performing the SPARK assay in HEK293T/17 cell cultures Support Protocol 1: Lentivirus preparation Support Protocol 2: Immunostaining of SPARK components.


Assuntos
Mapeamento de Interação de Proteínas , Proteínas , Células HEK293 , Humanos , Transdução de Sinais , Técnicas do Sistema de Duplo-Híbrido
17.
Viruses ; 13(7)2021 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-34206990

RESUMO

Innate immunity during acute infection plays a critical role in the disease severity of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), and is likely to contribute to COVID-19 disease outcomes. Defensins are highly abundant innate immune factors in neutrophils and epithelial cells, including intestinal Paneth cells, and exhibit antimicrobial and immune-modulatory activities. In this study, we investigated the effects of human α- and ß-defensins and RC101, a θ-defensin analog, on SARS-CoV-2 infection. We found that human neutrophil peptides (HNPs) 1-3, human defensin (HD) 5 and RC101 exhibited potent antiviral activity against pseudotyped viruses expressing SARS-CoV-2 spike proteins. HNP4 and HD6 had weak anti-SARS-CoV-2 activity, whereas human ß-defensins (HBD2, HBD5 and HBD6) had no effect. HNP1, HD5 and RC101 also inhibited infection by replication-competent SARS-CoV-2 viruses and SARS-CoV-2 variants. Pretreatment of cells with HNP1, HD5 or RC101 provided some protection against viral infection. These defensins did not have an effect when provided post-infection, indicating their effect was directed towards viral entry. Indeed, HNP1 inhibited viral fusion but not the binding of the spike receptor-binding domain to hACE2. The anti-SARS-CoV-2 effect of defensins was influenced by the structure of the peptides, as linear unstructured forms of HNP1 and HD5 lost their antiviral function. Pro-HD5, the precursor of HD5, did not block infection by SARS-CoV-2. High virus titers overcame the effect of low levels of HNP1, indicating that defensins act on the virion. HNP1, HD5 and RC101 also blocked viral infection of intestinal and lung epithelial cells. The protective effects of defensins reported here suggest that they may be useful additives to the antivirus arsenal and should be thoroughly studied.


Assuntos
Defensinas/farmacologia , SARS-CoV-2/efeitos dos fármacos , Internalização do Vírus/efeitos dos fármacos , Células A549 , Células CACO-2 , Defensinas/classificação , Células Epiteliais/virologia , Células HEK293 , Células HeLa , Humanos , SARS-CoV-2/fisiologia
18.
Viruses ; 13(7)2021 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-34209034

RESUMO

Host plasma membrane protein SERINC5 is incorporated into budding retrovirus particles where it blocks subsequent entry into susceptible target cells. Three structurally unrelated proteins encoded by diverse retroviruses, human immunodeficiency virus type 1 (HIV-1) Nef, equine infectious anemia virus (EIAV) S2, and ecotropic murine leukemia virus (MLV) GlycoGag, disrupt SERINC5 antiviral activity by redirecting SERINC5 from the site of virion assembly on the plasma membrane to an internal RAB7+ endosomal compartment. Pseudotyping retroviruses with particular glycoproteins, e.g., vesicular stomatitis virus glycoprotein (VSV G), renders the infectivity of particles resistant to inhibition by virion-associated SERINC5. To better understand viral determinants for SERINC5-sensitivity, the effect of SERINC5 was assessed using HIV-1, MLV, and Mason-Pfizer monkey virus (M-PMV) virion cores, pseudotyped with glycoproteins from Arenavirus, Coronavirus, Filovirus, Rhabdovirus, Paramyxovirus, and Orthomyxovirus genera. SERINC5 restricted virions pseudotyped with glycoproteins from several retroviruses, an orthomyxovirus, a rhabdovirus, a paramyxovirus, and an arenavirus. Infectivity of particles pseudotyped with HIV-1, amphotropic-MLV (A-MLV), or influenza A virus (IAV) glycoproteins, was decreased by SERINC5, whether the core was provided by HIV-1, MLV, or M-PMV. In contrast, particles pseudotyped with glycoproteins from M-PMV, parainfluenza virus 5 (PIV5), or rabies virus (RABV) were sensitive to SERINC5, but only with particular retroviral cores. Resistance to SERINC5 did not correlate with reduced SERINC5 incorporation into particles, route of viral entry, or absolute infectivity of the pseudotyped virions. These findings indicate that some non-retroviruses may be sensitive to SERINC5 and that, in addition to the viral glycoprotein, the retroviral core influences sensitivity to SERINC5.


Assuntos
Interações Hospedeiro-Patógeno , Proteínas de Membrana/genética , Proteínas do Envelope Viral , Vírion/metabolismo , Vírus/metabolismo , Células HEK293 , HIV-1/metabolismo , Humanos , Vírus da Leucemia Murina/metabolismo , Proteínas de Membrana/imunologia , Retroviridae/classificação , Retroviridae/metabolismo , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Vírion/genética , Internalização do Vírus , Vírus/química , Vírus/classificação , Vírus/genética
19.
Sci Signal ; 14(690)2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34230209

RESUMO

Inorganic polyphosphates (polyPs) are linear polymers composed of repeated phosphate (PO4 3-) units linked together by multiple high-energy phosphoanhydride bonds. In addition to being a source of energy, polyPs have cytoprotective and antiviral activities. Here, we investigated the antiviral activities of long-chain polyPs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In molecular docking analyses, polyPs interacted with several conserved amino acid residues in angiotensin-converting enzyme 2 (ACE2), the host receptor that facilitates virus entry, and in viral RNA-dependent RNA polymerase (RdRp). ELISA and limited proteolysis assays using nano- LC-MS/MS mapped polyP120 binding to ACE2, and site-directed mutagenesis confirmed interactions between ACE2 and SARS-CoV-2 RdRp and identified the specific amino acid residues involved. PolyP120 enhanced the proteasomal degradation of both ACE2 and RdRp, thus impairing replication of the British B.1.1.7 SARS-CoV-2 variant. We thus tested polyPs for functional interactions with the virus in SARS-CoV-2-infected Vero E6 and Caco2 cells and in primary human nasal epithelial cells. Delivery of a nebulized form of polyP120 reduced the amounts of viral positive-sense genomic and subgenomic RNAs, of RNA transcripts encoding proinflammatory cytokines, and of viral structural proteins, thereby presenting SARS-CoV-2 infection in cells in vitro.


Assuntos
Antivirais/farmacologia , COVID-19/tratamento farmacológico , Polifosfatos/farmacologia , SARS-CoV-2/efeitos dos fármacos , Administração por Inalação , Sequência de Aminoácidos , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Antivirais/administração & dosagem , Antivirais/química , COVID-19/metabolismo , COVID-19/virologia , Células CACO-2 , Chlorocebus aethiops , RNA-Polimerase RNA-Dependente de Coronavírus/química , RNA-Polimerase RNA-Dependente de Coronavírus/genética , RNA-Polimerase RNA-Dependente de Coronavírus/metabolismo , Citocinas/metabolismo , Células HEK293 , Interações entre Hospedeiro e Microrganismos/efeitos dos fármacos , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/fisiologia , Humanos , Técnicas In Vitro , Modelos Biológicos , Simulação de Acoplamento Molecular , Nebulizadores e Vaporizadores , Polifosfatos/administração & dosagem , Polifosfatos/química , Complexo de Endopeptidases do Proteassoma/metabolismo , Domínios e Motivos de Interação entre Proteínas , Proteólise/efeitos dos fármacos , RNA Viral/genética , RNA Viral/metabolismo , SARS-CoV-2/genética , SARS-CoV-2/fisiologia , Homologia de Sequência de Aminoácidos , Transdução de Sinais/efeitos dos fármacos , Células Vero , Replicação Viral/efeitos dos fármacos
20.
Int J Mol Sci ; 22(11)2021 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-34204139

RESUMO

The prohibitin (PHB)-binding compound fluorizoline as well as PHB-downregulation activate the integrated stress response (ISR) in HEK293T and U2OS human cell lines. This activation is denoted by phosphorylation of eIF2α and increases in ATF4, ATF3, and CHOP protein levels. The blockage of the activation of the ISR by overexpression of GRP78, as well as an increase in IRE1 activity, indicate the presence of ER stress after fluorizoline treatment. The inhibition of the ER stress response in HEK293T and U2OS led to increased sensitivity to fluorizoline-induced apoptosis, indicating a pro-survival role of this pathway after fluorizoline treatment in these cell lines. Fluorizoline induced an increase in calcium concentration in the cytosol and the mitochondria. Finally, two different calcium chelators reduced fluorizoline-induced apoptosis in U2OS cells. Thus, we have found that fluorizoline causes increased ER stress and activation of the integrated stress response, which in HEK293T and U2OS cells are protective against fluorizoline-induced apoptosis.


Assuntos
Apoptose , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Tiazóis/farmacologia , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Linhagem Celular Tumoral , Respiração Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Células HEK293 , Homeostase/efeitos dos fármacos , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteínas Repressoras/metabolismo , Transdução de Sinais/efeitos dos fármacos
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