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1.
Molecules ; 26(17)2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34500646

RESUMO

Arachidonylethanolamide (anandamide) acts as an endogenous ligand of cannabinoid receptors, while other N-acylethanolamines (NAEs), such as palmitylethanolamide and oleylethanolamide, show analgesic, anti-inflammatory, and appetite-suppressing effects through other receptors. In mammalian tissues, NAEs, including anandamide, are produced from glycerophospholipid via N-acyl-phosphatidylethanolamine (NAPE). The ɛ isoform of cytosolic phospholipase A2 (cPLA2) functions as an N-acyltransferase to form NAPE. Since the cPLA2 family consists of six isoforms (α, ß, γ, δ, ɛ, and ζ), the present study investigated a possible involvement of isoforms other than ɛ in the NAE biosynthesis. Firstly, when the cells overexpressing one of the cPLA2 isoforms were labeled with [14C]ethanolamine, the increase in the production of [14C]NAPE was observed only with the ɛ-expressing cells. Secondly, when the cells co-expressing ɛ and one of the other isoforms were analyzed, the increase in [14C]N-acyl-lysophosphatidylethanolamine (lysoNAPE) and [14C]NAE was seen with the combination of ɛ and γ isoforms. Furthermore, the purified cPLA2γ hydrolyzed not only NAPE to lysoNAPE, but also lysoNAPE to glycerophospho-N-acylethanolamine (GP-NAE). Thus, the produced GP-NAE was further hydrolyzed to NAE by glycerophosphodiesterase 1. These results suggested that cPLA2γ is involved in the biosynthesis of NAE by its phospholipase A1/A2 and lysophospholipase activities.


Assuntos
Etanolaminas/metabolismo , Fosfolipases A2/metabolismo , Isoformas de Proteínas/metabolismo , Aciltransferases/metabolismo , Amidas/metabolismo , Animais , Ácidos Araquidônicos/metabolismo , Linhagem Celular , Endocanabinoides/metabolismo , Etanolamina/metabolismo , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ácidos Oleicos/metabolismo , Ácidos Palmíticos/metabolismo , Fosfatidiletanolaminas/metabolismo , Diester Fosfórico Hidrolases/metabolismo , Alcamidas Poli-Insaturadas/metabolismo
2.
Int J Mol Sci ; 22(17)2021 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-34502274

RESUMO

Heat shock proteins (HSPs) are a large group of chaperones found in most eukaryotes and bacteria. They are responsible for the correct protein folding, protection of the cell against stressors, presenting immune and inflammatory cytokines; furthermore, they are important factors in regulating cell differentiation, survival and death. Although the biological function of HSPs is to maintain cell homeostasis, some of them can be used by viruses both to fold their proteins and increase the chances of survival in unfavorable host conditions. Folding viral proteins as well as replicating many different viruses are carried out by, among others, proteins from the HSP70 and HSP90 families. In some cases, the HSP70 family proteins directly interact with viral polymerase to enhance viral replication or they can facilitate the formation of a viral replication complex and/or maintain the stability of complex proteins. It is known that HSP90 is important for the expression of viral genes at both the transcriptional and the translational levels. Both of these HSPs can form a complex with HSP90 and, consequently, facilitate the entry of the virus into the cell. Current studies have shown the biological significance of HSPs in the course of infection SARS-CoV-2. A comprehensive understanding of chaperone use during viral infection will provide new insight into viral replication mechanisms and therapeutic potential. The aim of this study is to describe the molecular basis of HSP70 and HSP90 participation in some viral infections and the potential use of these proteins in antiviral therapy.


Assuntos
Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Viroses/patologia , COVID-19/metabolismo , COVID-19/patologia , COVID-19/virologia , Vírus de DNA/fisiologia , Humanos , Isoformas de Proteínas/metabolismo , Vírus de RNA/fisiologia , SARS-CoV-2/isolamento & purificação , Viroses/metabolismo , Viroses/virologia
3.
Toxicol Lett ; 350: 267-282, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34352333

RESUMO

The open source database "OpenCYP database" has been developed based on the results of extensive literature searches from the peer-reviewed literature. OpenCYP provides data on human variability on baseline of activities and polymophism frequencies for selected cytochrome P-450 isoforms (CYP1A2, CYP2A6, CYP2D6, CYP3A4/3A5 and CYP3A7) in healthy adult populations from world populations. CYP enzymatic activities were generally expressed as the metabolic ratio (MR) between an unchanged probe drug and its metabolite(s) in urine or plasma measured in healthy adults. Data on other age groups were very limited and fragmented, constituting an important data gap. Quantitative comparisons were often hampered by the different experimental conditions used. However, variability was quite limited for CYP1A2, using caffeine as a probe substrate, with a symmetrical distribution of metabolic activity values. For CYP3A4, human variability was dependent on the probe substrate itself with low variability when data considering the dextromethorphan/demethilathed metabolite MR were used and large variability when the urinary 6ß-hydroxycortisol/cortisol ratio was used. The largest variability in CYP activity was shown for CYP2D6 activity, after oral dosing of dextromethorphan, for which genetic polymorphisms are well characterised and constitute a significant source of variability. It is foreseen that the OpenCYP database can contribute to promising tools to support the further development of QIVIVE and PBK models for human risk assessment of chemicals particularly when combined with information on isoform-specific content in cells using proteomic approaches.


Assuntos
Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Bases de Dados Genéticas , Polimorfismo Genético , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Vigilância da População , Proteômica
4.
Int J Mol Sci ; 22(15)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34360783

RESUMO

Ca2+ ion channels are critical in a variety of physiological events, including cell growth, differentiation, gene transcription and apoptosis. One such essential entry pathway for calcium into the cell is the Ca2+ release-activated Ca2+ (CRAC) channel. It consists of the Ca2+ sensing protein, stromal interaction molecule 1 (STIM1) located in the endoplasmic reticulum (ER) and a Ca2+ ion channel Orai in the plasma membrane. The Orai channel family includes three homologues Orai1, Orai2 and Orai3. While Orai1 is the "classical" Ca2+ ion channel within the CRAC channel complex and plays a universal role in the human body, there is increasing evidence that Orai2 and Orai3 are important in specific physiological and pathophysiological processes. This makes them an attractive target in drug discovery, but requires a detailed understanding of the three Orai channels and, in particular, their differences. Orai channel activation is initiated via Ca2+ store depletion, which is sensed by STIM1 proteins, and induces their conformational change and oligomerization. Upon STIM1 coupling, Orai channels activate to allow Ca2+ permeation into the cell. While this activation mechanism is comparable among the isoforms, they differ by a number of functional and structural properties due to non-conserved regions in their sequences. In this review, we summarize the knowledge as well as open questions in our current understanding of the three isoforms in terms of their structure/function relationship, downstream signaling and physiology as well as pathophysiology.


Assuntos
Canais de Cálcio Ativados pela Liberação de Cálcio , Sinalização do Cálcio , Cálcio , Retículo Endoplasmático , Animais , Cálcio/química , Cálcio/metabolismo , Canais de Cálcio Ativados pela Liberação de Cálcio/química , Canais de Cálcio Ativados pela Liberação de Cálcio/genética , Canais de Cálcio Ativados pela Liberação de Cálcio/metabolismo , Retículo Endoplasmático/química , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Humanos , Proteínas de Neoplasias/química , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Molécula 1 de Interação Estromal/química , Molécula 1 de Interação Estromal/genética , Molécula 1 de Interação Estromal/metabolismo , Relação Estrutura-Atividade
5.
Sci Transl Med ; 13(605)2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34349032

RESUMO

Transforming growth factor-ß (TGFß) is a key driver of fibrogenesis. Three TGFß isoforms (TGFß1, TGFß2, and TGFß3) in mammals have distinct functions in embryonic development; however, the postnatal pathological roles and activation mechanisms of TGFß2 and TGFß3 have not been well characterized. Here, we show that the latent forms of TGFß2 and TGFß3 can be activated by integrin-independent mechanisms and have lower activation thresholds compared to TGFß1. Unlike TGFB1, TGFB2 and TGFB3 expression is increased in human lung and liver fibrotic tissues compared to healthy control tissues. Thus, TGFß2 and TGFß3 may play a pathological role in fibrosis. Inducible conditional knockout mice and anti-TGFß isoform-selective antibodies demonstrated that TGFß2 and TGFß3 are independently involved in mouse fibrosis models in vivo, and selective TGFß2 and TGFß3 inhibition does not lead to the increased inflammation observed with pan-TGFß isoform inhibition. A cocrystal structure of a TGFß2-anti-TGFß2/3 antibody complex reveals an allosteric isoform-selective inhibitory mechanism. Therefore, inhibiting TGFß2 and/or TGFß3 while sparing TGFß1 may alleviate fibrosis without toxicity concerns associated with pan-TGFß blockade.


Assuntos
Fator de Crescimento Transformador beta2 , Fator de Crescimento Transformador beta3 , Animais , Modelos Animais de Doenças , Feminino , Fibrose , Humanos , Camundongos , Isoformas de Proteínas/metabolismo , Fator de Crescimento Transformador beta2/metabolismo , Fator de Crescimento Transformador beta3/metabolismo
6.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34445673

RESUMO

The transcription factor p63, one of the p53 family members, plays an essential role in regulating maternal reproduction and genomic integrity as well as epidermal development. TP63 (human)/Trp63 (mouse) produces multiple isoforms: TAp63 and ΔNp63, which possess a different N-terminus depending on two different promoters, and p63a, p63b, p63g, p63δ, and p63ε as products of alternative splicing at the C-terminus. TAp63 expression turns on in the nuclei of primordial germ cells in females and is maintained mainly in the oocyte nuclei of immature follicles. It has been established that TAp63 is the genomic guardian in oocytes of the female ovaries and plays a central role in determining the oocyte fate upon oocyte damage. Lately, there is increasing evidence that TP63 mutations are connected with female infertility, including isolated premature ovarian insufficiency (POI) and syndromic POI. Here, we review the biological functions of p63 in females and discuss the consequences of p63 mutations, which result in infertility in human patients.


Assuntos
Fertilidade/genética , Transativadores/genética , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor/genética , Processamento Alternativo/genética , Animais , Núcleo Celular/metabolismo , Feminino , Genes p53/genética , Humanos , Camundongos , Mutação/genética , Oócitos/metabolismo , Ovário/metabolismo , Insuficiência Ovariana Primária/metabolismo , Isoformas de Proteínas/metabolismo , Transativadores/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo
7.
Toxicol Lett ; 350: 162-170, 2021 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-34256091

RESUMO

Carboxylesterases (CES) are an important class of enzymes involved in the hydrolysis of a range of chemicals and show large inter-individual variability in vitro. An extensive literature search was performed to identify in vivo probe substrates for CES1 and CES2 together with their protein content and enzymatic activity. Human pharmacokinetic (PK) data on Cmax, clearance, and AUC were extracted from 89 publications and Bayesian meta-analysis was performed using a hierarchical model to derive CES-related variability distributions and related uncertainty factors (UF). The CES-related variability indicated that 97.5% of healthy adults are covered by the kinetic default UF (3.16), except for clopidogrel and dabigatran etexilate. Clopidogrel is metabolised for a small amount by the polymorphic CYP2C19, which can have an impact on the overall pharmacokinetics, while the variability seen for dabigatran etexilate might be due to differences in the absorption, since this can be influenced by food intake. The overall CES-related variability was moderate to high in vivo (

Assuntos
Carboxilesterase/química , Carboxilesterase/metabolismo , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Medição de Risco/métodos , Adolescente , Adulto , Idoso , Teorema de Bayes , Exposição Ambiental , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Incerteza , Adulto Jovem
8.
Nat Commun ; 12(1): 4212, 2021 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-34244496

RESUMO

CSR-1 is an essential Argonaute protein that binds to a subclass of 22G-RNAs targeting most germline-expressed genes. Here we show that the two isoforms of CSR-1 have distinct expression patterns; CSR-1B is ubiquitously expressed throughout the germline and during all stages of development while CSR-1A expression is restricted to germ cells undergoing spermatogenesis. Furthermore, CSR-1A associates preferentially with 22G-RNAs mapping to spermatogenesis-specific genes whereas CSR-1B-bound small RNAs map predominantly to oogenesis-specific genes. Interestingly, the exon unique to CSR-1A contains multiple dimethylarginine modifications, which are necessary for the preferential binding of CSR-1A to spermatogenesis-specific 22G-RNAs. Thus, we have discovered a regulatory mechanism for C. elegans Argonaute proteins that allows for specificity of small RNA binding between similar Argonaute proteins with overlapping temporal and spatial localization.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/crescimento & desenvolvimento , Regulação da Expressão Gênica no Desenvolvimento , Interferência de RNA , Espermatogênese/genética , Animais , Animais Geneticamente Modificados , Arginina/metabolismo , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Éxons/genética , Feminino , Masculino , Metilação , Oogênese/genética , Ligação Proteica/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Interferente Pequeno/metabolismo , Processos de Determinação Sexual/genética
9.
Int J Mol Sci ; 22(12)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207662

RESUMO

p62/Sequestosome-1 (p62) is a multifunctional adaptor protein and is also a constant component of disease-associated protein aggregates, including Mallory-Denk bodies (MDBs), in steatohepatitis and hepatocellular carcinoma. We investigated the interaction of the two human p62 isoforms, p62-H1 (full-length isoform) and p62-H2 (partly devoid of PB1 domain), with keratins 8 and 18, the major components of MDBs. In human liver, p62-H2 is expressed two-fold higher compared to p62-H1 at the mRNA level and is present in slightly but not significantly higher concentrations at the protein level. Co-transfection studies in CHO-K1 cells, PLC/PRF/5 cells as well as p62- total-knockout and wild-type mouse fibroblasts revealed marked differences in the cytoplasmic distribution and aggregation behavior of the two p62 isoforms. Transfection-induced overexpression of p62-H2 generated large cytoplasmic aggregates in PLC/PRF/5 and CHO-K1 cells that mostly co-localized with transfected keratins resembling MDBs or (transfection without keratins) intracytoplasmic hyaline bodies. In fibroblasts, however, transfected p62-H2 was predominantly diffusely distributed in the cytoplasm. Aggregation of p62-H2 and p62ΔSH2 as well as the interaction with K8 (but not with K18) involves acquisition of cross-ß-sheet conformation as revealed by staining with luminescent conjugated oligothiophenes. These results indicate the importance of considering p62 isoforms in protein aggregation disease.


Assuntos
Queratinas/metabolismo , Agregados Proteicos , Proteína Sequestossoma-1/metabolismo , Animais , Células CHO , Cricetulus , Humanos , Queratinas/genética , Camundongos , Camundongos Knockout , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteína Sequestossoma-1/genética
10.
J Immunol ; 207(3): 765-770, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34301840

RESUMO

Glucocorticoids are a highly effective first-line treatment option for many inflammatory diseases, including asthma. Some patients develop a steroid-resistant condition, yet, the cellular and molecular mechanisms underlying steroid resistance remain largely unknown. In this study, we used a murine model of steroid-resistant airway inflammation and report that combining systemic dexamethasone and intranasal IL-27 is able to reverse the inflammation. Foxp3+ regulatory T cells (Tregs) were required during dexamethasone/IL-27 treatment of steroid-resistant allergic inflammation, and importantly, direct stimulation of Tregs via glucocorticoid or IL-27 receptors was essential. Mechanistically, IL-27 stimulation in Tregs enhanced expression of the agonistic glucocorticoid receptor-α isoform. Overexpression of inhibitory glucocorticoid receptor-ß isoform in Tregs alone was sufficient to elicit steroid resistance in a steroid-sensitive allergic inflammation model. Taken together, our results demonstrate for the first time, to our knowledge, that Tregs are instrumental during steroid resistance and that manipulating steroid responsiveness in Tregs may represent a novel strategy to treat steroid refractory asthma.


Assuntos
Asma/imunologia , Dexametasona/uso terapêutico , Interleucina-27/uso terapêutico , Hipersensibilidade Respiratória/imunologia , Linfócitos T Reguladores/imunologia , Alérgenos/imunologia , Animais , Asma/tratamento farmacológico , Células Cultivadas , Modelos Animais de Doenças , Resistência a Medicamentos , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ovalbumina/imunologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Hipersensibilidade Respiratória/tratamento farmacológico
11.
Nucleic Acids Res ; 49(15): 8836-8865, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34329465

RESUMO

The Caenorhabditis elegans genome encodes nineteen functional Argonaute proteins that use 22G-RNAs, 26G-RNAs, miRNAs or piRNAs to regulate target transcripts. Only one Argonaute is essential under normal laboratory conditions: CSR-1. While CSR-1 has been studied widely, nearly all studies have overlooked the fact that the csr-1 locus encodes two isoforms. These isoforms differ by an additional 163 amino acids present in the N-terminus of CSR-1a. Using CRISPR-Cas9 genome editing to introduce GFP::3xFLAG into the long (CSR-1a) and short (CSR-1b) isoforms, we found that CSR-1a is expressed during spermatogenesis and in several somatic tissues, including the intestine. CSR-1b is expressed constitutively in the germline. small RNA sequencing of CSR-1 complexes shows that they interact with partly overlapping sets of 22G-RNAs. Phenotypic analyses reveal that the essential functions of csr-1 described in the literature coincide with CSR-1b, while CSR-1a plays tissue specific functions. During spermatogenesis, CSR-1a integrates into an sRNA regulatory network including ALG-3, ALG-4 and WAGO-10 that is necessary for fertility at 25°C. In the intestine, CSR-1a silences immunity and pathogen-responsive genes, and its loss results in improved survival from the pathogen Pseudomonas aeruginosa. Our findings functionally distinguish the CSR-1 isoforms and highlight the importance of studying each AGO isoform independently.


Assuntos
Proteínas de Caenorhabditis elegans/fisiologia , Caenorhabditis elegans/genética , Espermatogênese/genética , Alelos , Animais , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Feminino , Fertilidade , Expressão Gênica , Masculino , Mutação , Oócitos/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/fisiologia , Pequeno RNA não Traduzido/metabolismo , Espermatozoides/metabolismo
12.
Int J Mol Sci ; 22(12)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207510

RESUMO

Interstitial lung diseases (ILDs) comprise different fibrotic lung disorders characterized by cellular proliferation, interstitial inflammation, and fibrosis. The JAK/STAT molecular pathway is activated under the interaction of a broad number of profibrotic/pro-inflammatory cytokines, such as IL-6, IL-11, and IL-13, among others, which are increased in different ILDs. Similarly, several growth factors over-expressed in ILDs, such as platelet-derived growth factor (PDGF), transforming growth factor ß1 (TGF-ß1), and fibroblast growth factor (FGF) activate JAK/STAT by canonical or non-canonical pathways, which indicates a predominant role of JAK/STAT in ILDs. Between the different JAK/STAT isoforms, it appears that JAK2/STAT3 are predominant, initiating cellular changes observed in ILDs. This review analyzes the expression and distribution of different JAK/STAT isoforms in ILDs lung tissue and different cell types related to ILDs, such as lung fibroblasts and alveolar epithelial type II cells and analyzes JAK/STAT activation. The effect of JAK/STAT phosphorylation on cellular fibrotic processes, such as proliferation, senescence, autophagy, endoplasmic reticulum stress, or epithelial/fibroblast to mesenchymal transition will be described. The small molecules directed to inhibit JAK/STAT activation were assayed in vitro and in in vivo models of pulmonary fibrosis, and different JAK inhibitors are currently approved for myeloproliferative disorders. Recent evidence indicates that JAK inhibitors or monoclonal antibodies directed to block IL-6 are used as compassionate use to attenuate the excessive inflammation and lung fibrosis related to SARS-CoV-2 virus. These altogether indicate that JAK/STAT pathway is an attractive target to be proven in future clinical trials of lung fibrotic disorders.


Assuntos
Janus Quinases/metabolismo , Doenças Pulmonares Intersticiais/patologia , Fatores de Transcrição STAT/metabolismo , Senescência Celular , Estresse do Retículo Endoplasmático , Humanos , Interleucinas/metabolismo , Janus Quinases/antagonistas & inibidores , Janus Quinases/genética , Doenças Pulmonares Intersticiais/tratamento farmacológico , Doenças Pulmonares Intersticiais/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/metabolismo , Inibidores de Proteínas Quinases/uso terapêutico , Fatores de Transcrição STAT/antagonistas & inibidores , Fatores de Transcrição STAT/genética , Transdução de Sinais
13.
Cell Prolif ; 54(8): e13096, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34240779

RESUMO

OBJECTIVES: PKM1 and PKM2, which are generated from the alternative splicing of PKM gene, play important roles in tumourigenesis and embryonic development as rate-limiting enzymes in glycolytic pathway. However, because of the lack of appropriate techniques, the specific functions of the 2 PKM splicing isoforms have not been clarified endogenously yet. MATERIALS AND METHODS: In this study, we used CRISPR-based base editors to perturbate the endogenous alternative splicing of PKM by introducing mutations into the splicing junction sites in HCT116 cells and zebrafish embryos. Sanger sequencing, agarose gel electrophoresis and targeted deep sequencing assays were utilized for identifying mutation efficiencies and detecting PKM1/2 splicing isoforms. Cell proliferation assays and RNA-seq analysis were performed to describe the effects of perturbation of PKM1/2 splicing in tumour cell growth and zebrafish embryo development. RESULTS: The splicing sites of PKM, a 5' donor site of GT and a 3' acceptor site of AG, were efficiently mutated by cytosine base editor (CBE; BE4max) and adenine base editor (ABE; ABEmax-NG) with guide RNAs (gRNAs) targeting the splicing sites flanking exons 9 and 10 in HCT116 cells and/or zebrafish embryos. The mutations of the 5' donor sites of GT flanking exons 9 or 10 into GC resulted in specific loss of PKM1 or PKM2 expression as well as the increase in PKM2 or PKM1 respectively. Specific loss of PKM1 promoted cell proliferation of HCT116 cells and upregulated the expression of cell cycle regulators related to DNA replication and cell cycle phase transition. In contrast, specific loss of PKM2 suppressed cell growth of HCT116 cells and resulted in growth retardation of zebrafish. Meanwhile, we found that mutation of PKM1/2 splicing sites also perturbated the expression of non-canonical PKM isoforms and produced some novel splicing isoforms. CONCLUSIONS: This work proved that CRISPR-based base editing strategy can be used to disrupt the endogenous alternative splicing of genes of interest to study the function of specific splicing isoforms in vitro and in vivo. It also reminded us to notice some novel or undesirable splicing isoforms by targeting the splicing junction sites using base editors. In sum, we establish a platform to perturbate endogenous RNA splicing for functional investigation or genetic correction of abnormal splicing events in human diseases.


Assuntos
Edição de Genes , Piruvato Quinase/metabolismo , Processamento Alternativo , Animais , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proliferação de Células , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Regulação para Baixo , Éxons , Feminino , Células HCT116 , Humanos , Mutagênese , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Piruvato Quinase/genética , Regulação para Cima , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
14.
Nat Commun ; 12(1): 4230, 2021 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-34244494

RESUMO

Extracellular matrix protein-1 (ECM1) promotes tumorigenesis in multiple organs but the mechanisms associated to ECM1 isoform subtypes have yet to be clarified. We report in this study that the secretory ECM1a isoform induces tumorigenesis through the GPR motif binding to integrin αXß2 and the activation of AKT/FAK/Rho/cytoskeleton signaling. The ATP binding cassette subfamily G member 1 (ABCG1) transduces the ECM1a-integrin αXß2 interactive signaling to facilitate the phosphorylation of AKT/FAK/Rho/cytoskeletal molecules and to confer cancer cell cisplatin resistance through up-regulation of the CD326-mediated cell stemness. On the contrary, the non-secretory ECM1b isoform binds myosin and blocks its phosphorylation, impairing cytoskeleton-mediated signaling and tumorigenesis. Moreover, ECM1a induces the expression of the heterogeneous nuclear ribonucleoprotein L like (hnRNPLL) protein to favor the alternative mRNA splicing generating ECM1a. ECM1a, αXß2, ABCG1 and hnRNPLL higher expression associates with poor survival, while ECM1b higher expression associates with good survival. These results highlight ECM1a, integrin αXß2, hnRNPLL and ABCG1 as potential targets for treating cancers associated with ECM1-activated signaling.


Assuntos
Processamento Alternativo , Carcinoma Epitelial do Ovário/genética , Proteínas da Matriz Extracelular/metabolismo , Recidiva Local de Neoplasia/epidemiologia , Neoplasias Ovarianas/genética , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Animais , Carcinoma Epitelial do Ovário/mortalidade , Carcinoma Epitelial do Ovário/patologia , Carcinoma Epitelial do Ovário/terapia , Linhagem Celular Tumoral , Quimioterapia Adjuvante , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Intervalo Livre de Doença , Resistencia a Medicamentos Antineoplásicos/genética , Proteínas da Matriz Extracelular/genética , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Ribonucleoproteínas Nucleares Heterogêneas/genética , Humanos , Integrina alfaXbeta2/genética , Integrina alfaXbeta2/metabolismo , Estimativa de Kaplan-Meier , Camundongos , Pessoa de Meia-Idade , Mutação , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia , Células-Tronco Neoplásicas/patologia , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/terapia , Ovário/patologia , Ovário/cirurgia , Fosforilação/genética , Prognóstico , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA-Seq , Transdução de Sinais/genética , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Int J Mol Sci ; 22(14)2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34299369

RESUMO

Absence seizures are associated with generalised synchronous 2.5-4 Hz spike-wave discharges causing brief and sudden alteration of awareness during childhood, which is known as childhood absence epilepsy (CAE). CAE is also associated with impaired learning, psychosocial challenges, and physical danger. Absence seizures arise from disturbances within the cortico-thalamocortical (CTC) network, including dysfunctional feed-forward inhibition (FFI); however, the precise mechanisms remain unclear. In epileptic stargazers, a genetic mouse model of CAE with chronic seizures, levels of γ-aminobutyric acid (GABA), and expression of GABA receptors are altered within the CTC network, implicating altered GABAergic transmission in absence seizures. However, the expression of GABA synthesising enzymes (GAD65 and GAD67) and GABA transporters (GAT-1 and 3) have not yet been characterised within absence seizure models. We found a specific upregulation of GAD65 in the somatosensory cortex but not the thalamus of epileptic stargazer mice. No differences were detected in GAD67 and GAT-3 levels in the thalamus or somatosensory cortex. Then, we assessed if GAD65 upregulation also occurred in Gi-DREADD mice exhibiting acute absence seizures, but we found no change in the expression profiles of GAD65/67 or GAT-3. Thus, the upregulation of GAD65 in stargazers may be a compensatory mechanism in response to long-term dysfunctional FFI and chronic absence seizures.


Assuntos
Glutamato Descarboxilase/metabolismo , Isoformas de Proteínas/metabolismo , Ácido gama-Aminobutírico/metabolismo , Animais , Modelos Animais de Doenças , Epilepsia Tipo Ausência/metabolismo , Feminino , Masculino , Camundongos , Neurônios/metabolismo , Receptores de GABA/metabolismo , Convulsões/metabolismo , Córtex Somatossensorial/metabolismo , Tálamo/metabolismo
16.
Nat Commun ; 12(1): 4074, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34210960

RESUMO

The c-MET receptor is a receptor tyrosine kinase (RTK) that plays essential roles in normal cell development and motility. Aberrant activation of c-MET can lead to both tumors growth and metastatic progression of cancer cells. C-MET can be activated by either hepatocyte growth factor (HGF), or its natural isoform NK1. Here, we report the cryo-EM structures of c-MET/HGF and c-MET/NK1 complexes in the active state. The c-MET/HGF complex structure reveals that, by utilizing two distinct interfaces, one HGF molecule is sufficient to induce a specific dimerization mode of c-MET for receptor activation. The binding of heparin as well as a second HGF to the 2:1 c-MET:HGF complex further stabilize this active conformation. Distinct to HGF, NK1 forms a stable dimer, and bridges two c-METs in a symmetrical manner for activation. Collectively, our studies provide structural insights into the activation mechanisms of c-MET, and reveal how two isoforms of the same ligand use dramatically different mechanisms to activate the receptor.


Assuntos
Fator de Crescimento de Hepatócito/química , Fator de Crescimento de Hepatócito/metabolismo , Proteínas Proto-Oncogênicas c-met/química , Proteínas Proto-Oncogênicas c-met/metabolismo , Linhagem Celular , Microscopia Crioeletrônica , Células HEK293 , Heparina/metabolismo , Humanos , Ligantes , Modelos Moleculares , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Isoformas de Proteínas/metabolismo , Receptores da Neurocinina-1/metabolismo
17.
Handb Clin Neurol ; 182: 177-189, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34266591

RESUMO

Human genes show the highest efficacy of alternative splicing (AS) in the brain as compared to other tissues. Within the brain, a remarkably rich diversity of AS events was identified in the hypothalamus. The AS frequency is increased in the aging brain. Such AS events, as intron retention and accumulation of circular RNAs, were acknowledged as some of the main hallmarks of the aging brain. In Alzheimer's disease (AD) pivotal (tau gene, in particular), risk, candidate and other genes show significant alterations in AS. Therefore AD has been suggested to be a disease of dysregulated AS. One of the reported risk factors for AD is estrogen deficiency that may interfere with the extension of neurobrillary tangles. Mounting evidence suggests that estrogens may decrease hyperphosphorylated tau deposition in the brain. Furthermore, AS of estrogen receptor α (ERα) mRNA is decreased in AD brain areas with the highest tau load. These potential interactions among tau, estrogens, and ERα AS may be important for the development of therapeutic and preventive strategies for AD. The intriguing point is that the amount of splice variants of ERα in the hypothalamus and the hippocampus is increased in aging and decreased in AD, while ERα is one of the regulators of AS and is subject to AS itself.


Assuntos
Doença de Alzheimer , Receptores de Estrogênio , Envelhecimento , Processamento Alternativo/genética , Doença de Alzheimer/genética , Encéfalo/metabolismo , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Humanos , Hipotálamo/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Receptores de Estrogênio/metabolismo
18.
PLoS One ; 16(6): e0253458, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34185793

RESUMO

L-Dopa decarboxylase (DDC) is the most significantly co-expressed gene with ACE2, which encodes for the SARS-CoV-2 receptor angiotensin-converting enzyme 2 and the interferon-inducible truncated isoform dACE2. Our group previously showed the importance of DDC in viral infections. We hereby aimed to investigate DDC expression in COVID-19 patients and cultured SARS-CoV-2-infected cells, also in association with ACE2 and dACE2. We concurrently evaluated the expression of the viral infection- and interferon-stimulated gene ISG56 and the immune-modulatory, hypoxia-regulated gene EPO. Viral load and mRNA levels of DDC, ACE2, dACE2, ISG56 and EPO were quantified by RT-qPCR in nasopharyngeal swab samples from COVID-19 patients, showing no or mild symptoms, and from non-infected individuals. Samples from influenza-infected patients were analyzed in comparison. SARS-CoV-2-mediated effects in host gene expression were validated in cultured virus-permissive epithelial cells. We found substantially higher gene expression of DDC in COVID-19 patients (7.6-fold; p = 1.2e-13) but not in influenza-infected ones, compared to non-infected subjects. dACE2 was more elevated (2.9-fold; p = 1.02e-16) than ACE2 (1.7-fold; p = 0.0005) in SARS-CoV-2-infected individuals. ISG56 (2.5-fold; p = 3.01e-6) and EPO (2.6-fold; p = 2.1e-13) were also increased. Detected differences were not attributed to enrichment of specific cell populations in nasopharyngeal tissue. While SARS-CoV-2 virus load was positively associated with ACE2 expression (r≥0.8, p<0.001), it negatively correlated with DDC, dACE2 (r≤-0.7, p<0.001) and EPO (r≤-0.5, p<0.05). Moreover, a statistically significant correlation between DDC and dACE2 expression was observed in nasopharyngeal swab and whole blood samples of both COVID-19 and non-infected individuals (r≥0.7). In VeroE6 cells, SARS-CoV-2 negatively affected DDC, ACE2, dACE2 and EPO mRNA levels, and induced cell death, while ISG56 was enhanced at early hours post-infection. Thus, the regulation of DDC, dACE2 and EPO expression in the SARS-CoV-2-infected nasopharyngeal tissue is possibly related with an orchestrated antiviral response of the infected host as the virus suppresses these genes to favor its propagation.


Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , COVID-19/patologia , Dopa Descarboxilase/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adulto , Idoso , Enzima de Conversão de Angiotensina 2/genética , Área Sob a Curva , Descarboxilases de Aminoácido-L-Aromático , COVID-19/virologia , Dopa Descarboxilase/genética , Regulação para Baixo , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Eritropoetina/genética , Eritropoetina/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nasofaringe/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Curva ROC , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Regulação para Cima , Carga Viral
19.
Nat Commun ; 12(1): 3285, 2021 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-34078899

RESUMO

In peripheral nerves, Schwann cells form myelin and provide trophic support to axons. We previously showed that the mitochondrial protein prohibitin 2 can localize to the axon-Schwann-cell interface and is required for developmental myelination. Whether the homologous protein prohibitin 1 has a similar role, and whether prohibitins also play important roles in Schwann cell mitochondria is unknown. Here, we show that deletion of prohibitin 1 in Schwann cells minimally perturbs development, but later triggers a severe demyelinating peripheral neuropathy. Moreover, mitochondria are heavily affected by ablation of prohibitin 1 and demyelination occurs preferentially in cells with apparent mitochondrial loss. Furthermore, in response to mitochondrial damage, Schwann cells trigger the integrated stress response, but, contrary to what was previously suggested, this response is not detrimental in this context. These results identify a role for prohibitin 1 in myelin integrity and advance our understanding about the Schwann cell response to mitochondrial damage.


Assuntos
Nervo Femoral/metabolismo , Mitocôndrias/metabolismo , Proteínas Repressoras/genética , Células de Schwann/metabolismo , Nervo Isquiático/metabolismo , Nervo Tibial/metabolismo , Animais , Aspartato-Amônia Ligase/genética , Aspartato-Amônia Ligase/metabolismo , Axônios/metabolismo , Axônios/ultraestrutura , Fator de Iniciação 2 em Eucariotos/genética , Fator de Iniciação 2 em Eucariotos/metabolismo , Feminino , Nervo Femoral/patologia , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mitocôndrias/patologia , Bainha de Mielina/metabolismo , Bainha de Mielina/patologia , Fosfoenolpiruvato Carboxiquinase (ATP)/genética , Fosfoenolpiruvato Carboxiquinase (ATP)/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Repressoras/deficiência , Células de Schwann/patologia , Nervo Isquiático/patologia , Estresse Fisiológico , Nervo Tibial/patologia , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismo , Proteína 1 de Ligação a X-Box/genética , Proteína 1 de Ligação a X-Box/metabolismo , gama-Glutamilciclotransferase/genética , gama-Glutamilciclotransferase/metabolismo
20.
Nat Commun ; 12(1): 3810, 2021 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-34155216

RESUMO

To a large extent functional diversity in cells is achieved by the expansion of molecular complexity beyond that of the coding genome. Various processes create multiple distinct but related proteins per coding gene - so-called proteoforms - that expand the functional capacity of a cell. Evaluating proteoforms from classical bottom-up proteomics datasets, where peptides instead of intact proteoforms are measured, has remained difficult. Here we present COPF, a tool for COrrelation-based functional ProteoForm assessment in bottom-up proteomics data. It leverages the concept of peptide correlation analysis to systematically assign peptides to co-varying proteoform groups. We show applications of COPF to protein complex co-fractionation data as well as to more typical protein abundance vs. sample data matrices, demonstrating the systematic detection of assembly- and tissue-specific proteoform groups, respectively, in either dataset. We envision that the presented approach lays the foundation for a systematic assessment of proteoforms and their functional implications directly from bottom-up proteomic datasets.


Assuntos
Isoformas de Proteínas/análise , Proteômica/métodos , Algoritmos , Animais , Benchmarking , Humanos , Camundongos , Peptídeos/análise , Peptídeos/metabolismo , Isoformas de Proteínas/metabolismo , Proteômica/normas , Espectrometria de Massas em Tandem , Fluxo de Trabalho
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