Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.473
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Immunity ; 56(10): 2342-2357.e10, 2023 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-37625409

RESUMO

The heart is an autoimmune-prone organ. It is crucial for the heart to keep injury-induced autoimmunity in check to avoid autoimmune-mediated inflammatory disease. However, little is known about how injury-induced autoimmunity is constrained in hearts. Here, we reveal an unknown intramyocardial immunosuppressive program driven by Tbx1, a DiGeorge syndrome disease gene that encodes a T-box transcription factor (TF). We found induced profound lymphangiogenic and immunomodulatory gene expression changes in lymphatic endothelial cells (LECs) after myocardial infarction (MI). The activated LECs penetrated the infarcted area and functioned as intramyocardial immune hubs to increase the numbers of tolerogenic dendritic cells (tDCs) and regulatory T (Treg) cells through the chemokine Ccl21 and integrin Icam1, thereby inhibiting the expansion of autoreactive CD8+ T cells and promoting reparative macrophage expansion to facilitate post-MI repair. Mimicking its timing and implementation may be an additional approach to treating autoimmunity-mediated cardiac diseases.

2.
Nature ; 630(8015): 247-254, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38750358

RESUMO

The noradrenaline transporter has a pivotal role in regulating neurotransmitter balance and is crucial for normal physiology and neurobiology1. Dysfunction of noradrenaline transporter has been implicated in numerous neuropsychiatric diseases, including depression and attention deficit hyperactivity disorder2. Here we report cryo-electron microscopy structures of noradrenaline transporter in apo and substrate-bound forms, and as complexes with six antidepressants. The structures reveal a noradrenaline transporter dimer interface that is mediated predominantly by cholesterol and lipid molecules. The substrate noradrenaline binds deep in the central binding pocket, and its amine group interacts with a conserved aspartate residue. Our structures also provide insight into antidepressant recognition and monoamine transporter selectivity. Together, these findings advance our understanding of noradrenaline transporter regulation and inhibition, and provide templates for designing improved antidepressants to treat neuropsychiatric disorders.


Assuntos
Antidepressivos , Microscopia Crioeletrônica , Proteínas da Membrana Plasmática de Transporte de Norepinefrina , Norepinefrina , Multimerização Proteica , Humanos , Antidepressivos/química , Antidepressivos/metabolismo , Antidepressivos/farmacologia , Apoproteínas/química , Apoproteínas/metabolismo , Apoproteínas/ultraestrutura , Ácido Aspártico/química , Ácido Aspártico/metabolismo , Sítios de Ligação , Colesterol/metabolismo , Colesterol/química , Modelos Moleculares , Norepinefrina/metabolismo , Norepinefrina/química , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/antagonistas & inibidores , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/química , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/ultraestrutura , Ligação Proteica , Especificidade por Substrato
3.
Plant Cell ; 36(3): 746-763, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38041863

RESUMO

N 6-methyladenosine (m6A) is a common epitranscriptional mRNA modification in eukaryotes. Thirteen putative m6A readers, mostly annotated as EVOLUTIONARILY CONSERVED C-TERMINAL REGION (ECT) proteins, have been identified in Arabidopsis (Arabidopsis thaliana), but few have been characterized. Here, we show that the Arabidopsis m6A reader ECT1 modulates salicylic acid (SA)-mediated plant stress responses. ECT1 undergoes liquid-liquid phase separation in vitro, and its N-terminal prion-like domain is critical for forming in vivo cytosolic biomolecular condensates in response to SA or bacterial pathogens. Fluorescence-activated particle sorting coupled with quantitative PCR analyses unveiled that ECT1 sequesters SA-induced m6A modification-prone mRNAs through its conserved aromatic cage to facilitate their decay in cytosolic condensates, thereby dampening SA-mediated stress responses. Consistent with this finding, ECT1 overexpression promotes bacterial multiplication in plants. Collectively, our findings unequivocally link ECT1-associated cytosolic condensates to SA-dependent plant stress responses, advancing the current understanding of m6A readers and the SA signaling network.


Assuntos
Adenina/análogos & derivados , Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Ácido Salicílico/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas
4.
Mol Cell ; 74(1): 118-131.e7, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30819645

RESUMO

Alternative polyadenylation (APA) produces mRNA isoforms with different 3' UTR lengths. Previous studies indicated that 3' end processing and mRNA export are intertwined in gene regulation. Here, we show that mRNA export factors generally facilitate usage of distal cleavage and polyadenylation sites (PASs), leading to long 3' UTR isoform expression. By focusing on the export receptor NXF1, which exhibits the most potent effect on APA in this study, we reveal several gene features that impact NXF1-dependent APA, including 3' UTR size, gene size, and AT content. Surprisingly, NXF1 downregulation results in RNA polymerase II (Pol II) accumulation at the 3' end of genes, correlating with its role in APA regulation. Moreover, NXF1 cooperates with CFI-68 to facilitate nuclear export of long 3' UTR isoform with UGUA motifs. Together, our work reveals important roles of NXF1 in coordinating transcriptional dynamics, 3' end processing, and nuclear export of long 3' UTR transcripts, implicating NXF1 as a nexus of gene regulation.


Assuntos
Núcleo Celular/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Poliadenilação , RNA Mensageiro/biossíntese , Proteínas de Ligação a RNA/metabolismo , Transcrição Gênica , Regiões 3' não Traduzidas , Transporte Ativo do Núcleo Celular , Sítios de Ligação , Núcleo Celular/genética , Células HEK293 , Células HeLa , Humanos , Cinética , Proteínas de Transporte Nucleocitoplasmático/genética , Ligação Proteica , RNA Polimerase II/metabolismo , RNA Mensageiro/genética , Proteínas de Ligação a RNA/genética
5.
Mol Cell ; 74(6): 1164-1174.e4, 2019 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-31054975

RESUMO

Post-translational modifications of the RNA polymerase II C-terminal domain (CTD) coordinate the transcription cycle. Crosstalk between different modifications is poorly understood. Here, we show how acetylation of lysine residues at position 7 of characteristic heptad repeats (K7ac)-only found in higher eukaryotes-regulates phosphorylation of serines at position 5 (S5p), a conserved mark of polymerases initiating transcription. We identified the regulator of pre-mRNA-domain-containing (RPRD) proteins as reader proteins of K7ac. K7ac enhanced CTD peptide binding to the CTD-interacting domain (CID) of RPRD1A and RPRD1B proteins in isothermal calorimetry and molecular modeling experiments. Deacetylase inhibitors increased K7ac- and decreased S5-phosphorylated polymerases, consistent with acetylation-dependent S5 dephosphorylation by an RPRD-associated S5 phosphatase. Consistent with this model, RPRD1B knockdown increased S5p but enhanced K7ac, indicating that RPRD proteins recruit K7 deacetylases, including HDAC1. We also report autoregulatory crosstalk between K7ac and S5p via RPRD proteins and their interactions with acetyl- and phospho-eraser proteins.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas de Neoplasias/metabolismo , Isoformas de Proteínas/metabolismo , Processamento de Proteína Pós-Traducional , RNA Polimerase II/metabolismo , Acetilação , Sequência de Aminoácidos , Animais , Sítios de Ligação , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Células HEK293 , Humanos , Camundongos , Modelos Moleculares , Células NIH 3T3 , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/química , Proteínas de Neoplasias/genética , Fosforilação , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , RNA Polimerase II/química , RNA Polimerase II/genética , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Termodinâmica
6.
Nat Chem Biol ; 20(5): 615-623, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38167916

RESUMO

Cellular context is crucial for understanding the complex and dynamic kinase functions in health and disease. Systematic dissection of kinase-mediated cellular processes requires rapid and precise stimulation ('pulse') of a kinase of interest, as well as global and in-depth characterization ('chase') of the perturbed proteome under living conditions. Here we developed an optogenetic 'pulse-chase' strategy, termed decaging kinase coupled proteomics (DeKinomics), for proteome-wide profiling of kinase-driven phosphorylation at second-timescale in living cells. We took advantage of the 'gain-of-function' feature of DeKinomics to identify direct kinase substrates and further portrayed the global phosphorylation of understudied receptor tyrosine kinases under native cellular settings. DeKinomics offered a general activation-based strategy to study kinase functions with high specificity and temporal resolution under living conditions.


Assuntos
Proteômica , Humanos , Fosforilação , Proteômica/métodos , Proteoma/metabolismo , Optogenética/métodos , Células HEK293
7.
PLoS Biol ; 21(7): e3002189, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37459330

RESUMO

Plant-associated bacteria play important regulatory roles in modulating plant hormone auxin levels, affecting the growth and yields of crops. A conserved auxin degradation (iad) operon was recently identified in the Variovorax genomes, which is responsible for root growth inhibition (RGI) reversion, promoting rhizosphere colonization and root growth. However, the molecular mechanism underlying auxin degradation by Variovorax remains unclear. Here, we systematically screened Variovorax iad operon products and identified 2 proteins, IadK2 and IadD, that directly associate with auxin indole-3-acetic acid (IAA). Further biochemical and structural studies revealed that IadK2 is a highly IAA-specific ATP-binding cassette (ABC) transporter solute-binding protein (SBP), likely involved in IAA uptake. IadD interacts with IadE to form a functional Rieske non-heme dioxygenase, which works in concert with a FMN-type reductase encoded by gene iadC to transform IAA into the biologically inactive 2-oxindole-3-acetic acid (oxIAA), representing a new bacterial pathway for IAA inactivation/degradation. Importantly, incorporation of a minimum set of iadC/D/E genes could enable IAA transformation by Escherichia coli, suggesting a promising strategy for repurposing the iad operon for IAA regulation. Together, our study identifies the key components and underlying mechanisms involved in IAA transformation by Variovorax and brings new insights into the bacterial turnover of plant hormones, which would provide the basis for potential applications in rhizosphere optimization and ecological agriculture.


Assuntos
Ácidos Indolacéticos , Rizosfera , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Plantas/metabolismo , Bactérias/metabolismo , Óperon/genética
8.
PLoS Biol ; 21(9): e3002309, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37713449

RESUMO

The proton-activated chloride (PAC) channel plays critical roles in ischemic neuron death, but its activation mechanisms remain elusive. Here, we investigated the gating of PAC channels using its novel bifunctional modulator C77304. C77304 acted as a weak activator of the PAC channel, causing moderate activation by acting on its proton gating. However, at higher concentrations, C77304 acted as a weak inhibitor, suppressing channel activity. This dual function was achieved by interacting with 2 modulatory sites of the channel, each with different affinities and dependencies on the channel's state. Moreover, we discovered a protonation-independent voltage activation of the PAC channel that appears to operate through an ion-flux gating mechanism. Through scanning-mutagenesis and molecular dynamics simulation, we confirmed that E181, E257, and E261 in the human PAC channel serve as primary proton sensors, as their alanine mutations eliminated the channel's proton gating while sparing the voltage-dependent gating. This proton-sensing mechanism was conserved among orthologous PAC channels from different species. Collectively, our data unveils the polymodal gating and proton-sensing mechanisms in the PAC channel that may inspire potential drug development.

9.
Proc Natl Acad Sci U S A ; 120(50): e2311913120, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38060559

RESUMO

The Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus infects host cells by engaging its spike (S) protein with human ACE2 receptor. Recent studies suggest the involvement of integrins in SARS-CoV-2 infection through interaction with the S protein, but the underlying mechanism is not well understood. This study investigated the role of integrin α5ß1, which recognizes the Arg-Gly-Asp (RGD) motif in its physiological ligands, in S-mediated virus entry and cell-cell fusion. Our results showed that α5ß1 does not directly contribute to S-mediated cell entry, but it enhances S-mediated cell-cell fusion in collaboration with ACE2. This effect cannot be inhibited by the putative α5ß1 inhibitor ATN-161 or the high-affinity RGD-mimetic inhibitor MK-0429 but requires the participation of α5 cytoplasmic tail (CT). We detected a direct interaction between α5ß1 and the S protein, but this interaction does not rely on the RGD-containing receptor binding domain of the S1 subunit of the S protein. Instead, it involves the S2 subunit of the S protein and α5ß1 homo-oligomerization. Furthermore, we found that the S protein induces inflammatory responses in human endothelial cells, characterized by NF-κB activation, gasdermin D cleavage, and increased secretion of proinflammatory cytokines IL-6 and IL-1ß. These effects can be attenuated by the loss of α5 expression or inhibition of the α5 CT binding protein phosphodiesterase-4D (PDE4D), suggesting the involvement of α5 CT and PDE4D pathway. These findings provide molecular insights into the pathogenesis of SARS-CoV-2 mediated by a nonclassical RGD-independent ligand-binding and signaling function of integrin α5ß1 and suggest potential targets for antiviral treatment.


Assuntos
COVID-19 , Integrina alfa5beta1 , Humanos , Integrina alfa5beta1/metabolismo , SARS-CoV-2/metabolismo , Células Endoteliais/metabolismo , Fusão Celular , Enzima de Conversão de Angiotensina 2 , Oligopeptídeos/farmacologia , Integrinas/química , Inflamação , Glicoproteína da Espícula de Coronavírus/genética
10.
Genes Dev ; 32(5-6): 341-346, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29563185

RESUMO

The mixed-lineage leukemia (MLL)-AF10 fusion oncoprotein recruits DOT1L to the homeobox A (HOXA) gene cluster through its octapeptide motif leucine zipper (OM-LZ), thereby inducing and maintaining the MLL-AF10-associated leukemogenesis. However, the recognition mechanism between DOT1L and MLL-AF10 is unclear. Here, we present the crystal structures of both apo AF10OM-LZ and its complex with the coiled-coil domain of DOT1L. Disruption of the DOT1L-AF10 interface abrogates MLL-AF10-associated leukemic transformation. We further show that zinc stabilizes the DOT1L-AF10 complex and may be involved in the regulation of the HOXA gene expression. Our studies may also pave the way for the rational design of therapeutic drugs against MLL-rearranged leukemia.


Assuntos
Transformação Celular Neoplásica/patologia , Metiltransferases , Modelos Moleculares , Proteína de Leucina Linfoide-Mieloide , Fatores de Transcrição , Cristalização , Regulação Neoplásica da Expressão Gênica , Histona-Lisina N-Metiltransferase , Proteínas de Homeodomínio/genética , Humanos , Metiltransferases/química , Metiltransferases/metabolismo , Proteína de Leucina Linfoide-Mieloide/química , Proteína de Leucina Linfoide-Mieloide/metabolismo , Ligação Proteica , Domínios Proteicos , Estrutura Quaternária de Proteína , Relação Estrutura-Atividade , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Zinco/química
11.
Circulation ; 149(9): 684-706, 2024 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-37994595

RESUMO

BACKGROUND: The majority of people with diabetes are susceptible to cardiac dysfunction and heart failure, and conventional drug therapy cannot correct diabetic cardiomyopathy progression. Herein, we assessed the potential role and therapeutic value of USP28 (ubiquitin-specific protease 28) on the metabolic vulnerability of diabetic cardiomyopathy. METHODS: The type 2 diabetes mouse model was established using db/db leptin receptor-deficient mice and high-fat diet/streptozotocin-induced mice. Cardiac-specific knockout of USP28 in the db/db background mice was generated by crossbreeding db/m and Myh6-Cre+/USP28fl/fl mice. Recombinant adeno-associated virus serotype 9 carrying USP28 under cardiac troponin T promoter was injected into db/db mice. High glucose plus palmitic acid-incubated neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes were used to imitate diabetic cardiomyopathy in vitro. The molecular mechanism was explored through RNA sequencing, immunoprecipitation and mass spectrometry analysis, protein pull-down, chromatin immunoprecipitation sequencing, and chromatin immunoprecipitation assay. RESULTS: Microarray profiling of the UPS (ubiquitin-proteasome system) on the basis of db/db mouse hearts and diabetic patients' hearts demonstrated that the diabetic ventricle presented a significant reduction in USP28 expression. Diabetic Myh6-Cre+/USP28fl/fl mice exhibited more severe progressive cardiac dysfunction, lipid accumulation, and mitochondrial disarrangement, compared with their controls. On the other hand, USP28 overexpression improved systolic and diastolic dysfunction and ameliorated cardiac hypertrophy and fibrosis in the diabetic heart. Adeno-associated virus serotype 9-USP28 diabetic mice also exhibited less lipid storage, reduced reactive oxygen species formation, and mitochondrial impairment in heart tissues than adeno-associated virus serotype 9-null diabetic mice. As a result, USP28 overexpression attenuated cardiac remodeling and dysfunction, lipid accumulation, and mitochondrial impairment in high-fat diet/streptozotocin-induced type 2 diabetes mice. These results were also confirmed in neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes. RNA sequencing, immunoprecipitation and mass spectrometry analysis, chromatin immunoprecipitation assays, chromatin immunoprecipitation sequencing, and protein pull-down assay mechanistically revealed that USP28 directly interacted with PPARα (peroxisome proliferator-activated receptor α), deubiquitinating and stabilizing PPARα (Lys152) to promote Mfn2 (mitofusin 2) transcription, thereby impeding mitochondrial morphofunctional defects. However, such cardioprotective benefits of USP28 were largely abrogated in db/db mice with PPARα deletion and conditional loss-of-function of Mfn2. CONCLUSIONS: Our findings provide a USP28-modulated mitochondria homeostasis mechanism that involves the PPARα-Mfn2 axis in diabetic hearts, suggesting that USP28 activation or adeno-associated virus therapy targeting USP28 represents a potential therapeutic strategy for diabetic cardiomyopathy.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Cardiomiopatias Diabéticas , Células-Tronco Pluripotentes Induzidas , Ubiquitina Tiolesterase , Animais , Humanos , Camundongos , Ratos , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Cardiomiopatias Diabéticas/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Lipídeos , Camundongos Knockout , Miócitos Cardíacos/metabolismo , PPAR alfa/metabolismo , Estreptozocina/metabolismo , Estreptozocina/uso terapêutico , Ubiquitina Tiolesterase/análise , Ubiquitina Tiolesterase/metabolismo
12.
PLoS Pathog ; 19(5): e1011411, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37253057

RESUMO

Seneca virus A (SVA) is an emerging novel picornavirus that has recently been identified as the causative agent of many cases of porcine vesicular diseases in multiple countries. In addition to cleavage of viral polyprotein, the viral 3C protease (3Cpro) plays an important role in the regulation of several physiological processes involved in cellular antiviral responses by cleaving critical cellular proteins. Through a combination of crystallography, untargeted lipidomics, and immunoblotting, we identified the association of SVA 3Cpro with an endogenous phospholipid molecule, which binds to a unique region neighboring the proteolytic site of SVA 3Cpro. Our lipid-binding assays showed that SVA 3Cpro displayed preferred binding to cardiolipin (CL), followed by phosphoinositol-4-phosphate (PI4P) and sulfatide. Importantly, we found that the proteolytic activity of SVA 3Cpro was activated in the presence of the phospholipid, and the enzymatic activity is inhibited when the phospholipid-binding capacity decreased. Interestingly, in the wild-type SVA 3Cpro-substrate peptide structure, the cleavage residue cannot form a covalent binding to the catalytic cysteine residue to form the acyl-enzyme intermediate observed in several picornaviral 3Cpro structures. We observed a decrease in infectivity titers of SVA mutants harboring mutations that impaired the lipid-binding ability of 3Cpro, indicating a positive regulation of SVA infection capacity mediated by phospholipids. Our findings reveal a mutual regulation between the proteolytic activity and phospholipid-binding capacity in SVA 3Cpro, suggesting that endogenous phospholipid may function as an allosteric activator that regulate the enzyme's proteolytic activity during infection.


Assuntos
Cisteína Endopeptidases , Picornaviridae , Animais , Suínos , Cisteína Endopeptidases/metabolismo , Proteases Virais 3C/metabolismo , Peptídeo Hidrolases/metabolismo , Regulação Alostérica , Fosfolipídeos , Proteínas Virais/metabolismo
13.
Nat Chem Biol ; 19(1): 72-80, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36163384

RESUMO

The transient receptor potential vanilloid 2 (TRPV2) ion channel is a polymodal receptor widely involved in many physiological and pathological processes. Despite many TRPV2 modulators being identified, whether and how TRPV2 is regulated by endogenous lipids remains elusive. Here, we report an endogenous cholesterol molecule inside the vanilloid binding pocket (VBP) of TRPV2, with a 'head down, tail up' configuration, resolved at 3.2 Å using cryo-EM. Cholesterol binding antagonizes ligand activation of TRPV2, which is removed from VBP by methyl-ß-cyclodextrin (MßCD) as resolved at 2.9 Å. We also observed that estradiol (E2) potentiated TRPV2 activation by 2-aminoethoxydiphenyl borate (2-APB), a classic tool compound for TRP channels. Our cryo-EM structures (resolved at 2.8-3.3 Å) further suggest how E2 disturbed cholesterol binding and how 2-APB bound within the VBP with E2 or without both E2 and endogenous cholesterol, respectively. Therefore, our study has established the structural basis for ligand recognition of the inhibitory endogenous cholesterol and excitatory exogenous 2-APB in TRPV2.


Assuntos
Canais de Cátion TRPV , Canais de Cátion TRPV/química , Ligantes
14.
FASEB J ; 38(9): e23645, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38703043

RESUMO

Inflammation assumes a pivotal role in the aortic remodeling of aortic dissection (AD). Asiatic acid (AA), a triterpene compound, is recognized for its strong anti-inflammatory properties. Yet, its effects on ß-aminopropionitrile (BAPN)-triggered AD have not been clearly established. The objective is to determine whether AA attenuates adverse aortic remodeling in BAPN-induced AD and clarify potential molecular mechanisms. In vitro studies, RAW264.7 cells pretreated with AA were challenged with lipopolysaccharide (LPS), and then the vascular smooth muscle cells (VSMCs)-macrophage coculture system was established to explore intercellular interactions. To induce AD, male C57BL/6J mice at three weeks of age were administered BAPN at a dosage of 1 g/kg/d for four weeks. To decipher the mechanism underlying the effects of AA, RNA sequencing analysis was conducted, with subsequent validation of these pathways through cellular experiments. AA exhibited significant suppression of M1 macrophage polarization. In the cell coculture system, AA facilitated the transformation of VSMCs into a contractile phenotype. In the mouse model of AD, AA strikingly prevented the BAPN-induced increases in inflammation cell infiltration and extracellular matrix degradation. Mechanistically, RNA sequencing analysis revealed a substantial upregulation of CX3CL1 expression in BAPN group but downregulation in AA-treated group. Additionally, it was observed that the upregulation of CX3CL1 negated the beneficial impact of AA on the polarization of macrophages and the phenotypic transformation of VSMCs. Crucially, our findings revealed that AA is capable of downregulating CX3CL1 expression, accomplishing this by obstructing the nuclear translocation of NF-κB p65. The findings indicate that AA holds promise as a prospective treatment for adverse aortic remodeling by suppressing the activity of NF-κB p65/CX3CL1 signaling pathway.


Assuntos
Dissecção Aórtica , Quimiocina CX3CL1 , Camundongos Endogâmicos C57BL , Triterpenos Pentacíclicos , Transdução de Sinais , Fator de Transcrição RelA , Remodelação Vascular , Animais , Camundongos , Masculino , Dissecção Aórtica/metabolismo , Dissecção Aórtica/patologia , Dissecção Aórtica/tratamento farmacológico , Triterpenos Pentacíclicos/farmacologia , Remodelação Vascular/efeitos dos fármacos , Células RAW 264.7 , Transdução de Sinais/efeitos dos fármacos , Fator de Transcrição RelA/metabolismo , Quimiocina CX3CL1/metabolismo , Quimiocina CX3CL1/genética , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Aminopropionitrilo/farmacologia , Macrófagos/metabolismo , Macrófagos/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/efeitos dos fármacos
15.
Nature ; 568(7751): 240-243, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30944466

RESUMO

The plant hormone auxin has crucial roles in almost all aspects of plant growth and development. Concentrations of auxin vary across different tissues, mediating distinct developmental outcomes and contributing to the functional diversity of auxin. However, the mechanisms that underlie these activities are poorly understood. Here we identify an auxin signalling mechanism, which acts in parallel to the canonical auxin pathway based on the transport inhibitor response1 (TIR1) and other auxin receptor F-box (AFB) family proteins (TIR1/AFB receptors)1,2, that translates levels of cellular auxin to mediate differential growth during apical-hook development. This signalling mechanism operates at the concave side of the apical hook, and involves auxin-mediated C-terminal cleavage of transmembrane kinase 1 (TMK1). The cytosolic and nucleus-translocated C terminus of TMK1 specifically interacts with and phosphorylates two non-canonical transcriptional repressors of the auxin or indole-3-acetic acid (Aux/IAA) family (IAA32 and IAA34), thereby regulating ARF transcription factors. In contrast to the degradation of Aux/IAA transcriptional repressors in the canonical pathway, the newly identified mechanism stabilizes the non-canonical IAA32 and IAA34 transcriptional repressors to regulate gene expression and ultimately inhibit growth. The auxin-TMK1 signalling pathway originates at the cell surface, is triggered by high levels of auxin and shares a partially overlapping set of transcription factors with the TIR1/AFB signalling pathway. This allows distinct interpretations of different concentrations of cellular auxin, and thus enables this versatile signalling molecule to mediate complex developmental outcomes.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Sequência de Aminoácidos , Arabidopsis/citologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas F-Box/metabolismo , Ácidos Indolacéticos/antagonistas & inibidores , Mutação , Reguladores de Crescimento de Plantas/antagonistas & inibidores , Ligação Proteica , Proteínas Serina-Treonina Quinases/genética , Receptores de Superfície Celular/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo
16.
Nucleic Acids Res ; 51(17): 9442-9451, 2023 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-37587688

RESUMO

CRISPR-Cas systems act as the adaptive immune systems of bacteria and archaea, targeting and destroying invading foreign mobile genetic elements (MGEs) such as phages. MGEs have also evolved anti-CRISPR (Acr) proteins to inactivate the CRISPR-Cas systems. Recently, AcrIIC4, identified from Haemophilus parainfluenzae phage, has been reported to inhibit the endonuclease activity of Cas9 from Neisseria meningitidis (NmeCas9), but the inhibition mechanism is not clear. Here, we biochemically and structurally investigated the anti-CRISPR activity of AcrIIC4. AcrIIC4 folds into a helix bundle composed of three helices, which associates with the REC lobe of NmeCas9 and sgRNA. The REC2 domain of NmeCas9 is locked by AcrIIC4, perturbing the conformational dynamics required for the target DNA binding and cleavage. Furthermore, mutation of the key residues in the AcrIIC4-NmeCas9 and AcrIIC4-sgRNA interfaces largely abolishes the inhibitory effects of AcrIIC4. Our study offers new insights into the mechanism of AcrIIC4-mediated suppression of NmeCas9 and provides guidelines for the design of regulatory tools for Cas9-based gene editing applications.


Assuntos
Bacteriófagos , Sistemas CRISPR-Cas , Sistemas CRISPR-Cas/genética , Proteína 9 Associada à CRISPR/metabolismo , RNA Guia de Sistemas CRISPR-Cas , Edição de Genes , Bactérias/genética , Bacteriófagos/genética
17.
J Mol Cell Cardiol ; 186: 81-93, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37995517

RESUMO

AIM: Doxorubicin-induced cardiotoxicity (DIC) is an increasing problem, occurring in many cancer patients receiving anthracycline chemotherapy, ultimately leading to heart failure (HF). Unfortunately, DIC remains difficult to manage due to an ignorance regarding pathophysiological mechanisms. Our work aimed to evaluate the role of HSP47 in doxorubicin-induced HF, and to explore the molecular mechanisms. METHODS AND RESULTS: Mice were exposed to multi-intraperitoneal injection of doxorubicin (DOX, 4mg/kg/week, for 6 weeks continuously) to produce DIC. HSP47 expression was significantly upregulated in serum and in heart tissue in DOX-treated mice and in isolated cardiomyocytes. Mice with cardiac-specific HSP47 overexpression and knockdown were generated using recombinant adeno-associated virus (rAVV9) injection. Importantly, cardiac-specific HSP47 overexpression exacerbated cardiac dysfunction in DIC, while HSP47 knockdown prevented DOX-induced cardiac dysfunction, cardiac atrophy and fibrosis in vivo and in vitro. Mechanistically, we identified that HSP47 directly interacted with IRE1α in cardiomyocytes. Furthermore, we provided powerful evidence that HSP47-IRE1α complex promoted TXNIP/NLRP3 inflammasome and reinforced USP1-mediated NLRP3 ubiquitination. Moreover, NLRP3 deficiency in vivo conspicuously abolished HSP47-mediated cardiac atrophy and fibrogenesis under DOX condition. CONCLUSION: HSP47 was highly expressed in serum and cardiac tissue after doxorubicin administration. HSP47 contributed to long-term anthracycline chemotherapy-associated cardiac dysfunction in an NLRP3-dependent manner. HSP47 therefore represents a plausible target for future therapy of doxorubicin-induced HF.


Assuntos
Inflamassomos , Proteína 3 que Contém Domínio de Pirina da Família NLR , Camundongos , Humanos , Animais , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteínas de Choque Térmico HSP47/metabolismo , Cardiotoxicidade/metabolismo , Doxorrubicina/farmacologia , Endorribonucleases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Miócitos Cardíacos/metabolismo , Antibióticos Antineoplásicos/efeitos adversos , Atrofia/induzido quimicamente , Atrofia/metabolismo , Atrofia/patologia , Apoptose , Estresse Oxidativo
18.
J Struct Biol ; 216(1): 108070, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38395113

RESUMO

CRISPR-Cas system is an RNA-guided adaptive immune system widespread in bacteria and archaea. Among them, type III CRISPR-Cas systems are the most ancient throughout the CRISPR-Cas family, proving anti-phage defense through a crRNA-guided RNA targeting manner and possessing multiple enzymatic activities. Type III CRISPR-Cas systems comprise four typical members (type III-A to III-D) and two atypical members (type III-E and type III-F), providing immune defense through distinct mechanisms. Here, we delve into structural studies conducted on three well-characterized members: the type III-A, III-B, and III-E systems, provide an overview of the structural insights into the crRNA-guided target RNA cleavage, self/non-self discrimination, and the target RNA-dependent regulation of enzymatic subunits in the effector complex.


Assuntos
Sistemas CRISPR-Cas , RNA Guia de Sistemas CRISPR-Cas , Sistemas CRISPR-Cas/genética , RNA/genética , Bactérias/genética , Biologia
19.
Infect Immun ; 92(6): e0002624, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38767360

RESUMO

Schistosomiasis is a serious public health problem, and previous studies found that liver function and hepatic cells are damaged. To evaluate the serum parameters of liver function and fibrosis in schistosomiasis patients infected with Schistosoma japonicum (Schistosoma J.) and analyze the correlations between liver function and serum fibrosis markers in patients infected with Schistosoma J., this retrospective study enrolled 133 patients. The study population was divided into four groups: healthy people control group (n = 20), chronic schistosomiasis without liver cirrhosis (CS) group (n = 21), schistosomiasis cirrhosis without hypoalbuminemia (SC-HA) group (n = 68), and schistosomiasis cirrhosis with hypoalbuminemia (SC +HA) group (n = 24). Clinical and laboratory data were collected for analysis. In the multiple comparison of abnormal rates of aspartate aminotransferase (AST) and total bilirubin (TBIL), the abnormal rate of the SC +HA group was significantly higher than that of the other three groups (P < 0.05), and the abnormal rate of γ-GT in the SC +HA group was significantly higher than that in the control group (P < 0.05). Multiple comparison results of serum levels of fibrosis markers showed that the SC group had a significantly higher level of indexes than other groups (P < 0.05). The levels of TGF-ß1 in the CS group, SC-HA group and SC +HA group were significantly higher than those in the control group (P < 0.001). Our study demonstrated that the liver function and hepatic cells were damaged with the progression of liver disease in patients infected with Schistosoma J., and they played an important role in the occurrence and development of liver fibrosis.


Assuntos
Hepatócitos , Cirrose Hepática , Schistosoma japonicum , Esquistossomose Japônica , Humanos , Cirrose Hepática/patologia , Cirrose Hepática/parasitologia , Esquistossomose Japônica/complicações , Esquistossomose Japônica/patologia , Masculino , Feminino , Pessoa de Meia-Idade , Animais , Adulto , Estudos Retrospectivos , Hepatócitos/patologia , Hepatócitos/parasitologia , Biomarcadores/sangue , Idoso , Fígado/patologia , Fígado/parasitologia , Testes de Função Hepática
20.
Int J Cancer ; 154(6): 969-978, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-37874120

RESUMO

Some patients with marginal zone lymphoma (MZL) experience histological transformation to diffuse large B-cell lymphoma (DLBCL). Because of the paucity of long-term data on transformation, we conducted a population-based study to estimate the risk of transformation and its impact on survival in MZL. Using the Surveillance, Epidemiology and End Results database, we identified 23 221 patients with histology-proven MZL between 2000 and 2018. Competing risk method, Kaplan-Meier and Cox proportional hazards regression were performed to analyze time-to-event outcomes. Based on 420 events of transformation, the 10-year cumulative incidence rate of transformation is 2.23% (95% CI: 2.00%-2.46%) in MZL, 1.5% (95% CI: 1.3%-1.8%), 2.7% (95% CI: 2.3%-3.2%) and 5.8% (95% CI: 4.6%-7.1%) in extranodal, nodal and splenic MZL (EMZL, NMZL and SMZL), respectively. Patients with SMZL (subdistribution hazard ratio [SHR], 2.96; 95% CI: 2.21-3.96) or NMZL (SHR, 1.49; 95% CI: 1.17-1.90) have a higher risk of transformation than those with EMZL. For each MZL subtype, patients with transformation had a significantly shorter overall survival. Patients with transformation >18 months since MZL diagnosis had longer OS than those who presented within 18 months (5-year rate, 87.4% [95% CI: 83.7%-91.2%] vs 47.9% [95% CI: 38.8%-59.0%]; P < .001). Compared to patients with matched de novo DLBCL, those whose DLBCL was transformed from MZL had a shorter OS (5-year rate, 56.6% [95% CI: 51.9%-61.8%] vs 46.1% [95% CI: 40.9%-51.9%]; P < .001). We concluded that patients with SMZL had the highest risk of transformation. Regardless of MZL subtype, transformation resulted in significantly increased mortality.


Assuntos
Leucemia Linfocítica Crônica de Células B , Linfoma de Zona Marginal Tipo Células B , Linfoma Difuso de Grandes Células B , Humanos , Linfoma de Zona Marginal Tipo Células B/epidemiologia , Linfoma de Zona Marginal Tipo Células B/diagnóstico , Linfoma Difuso de Grandes Células B/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA