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1.
Nucleic Acids Res ; 51(14): 7342-7356, 2023 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-37326017

RESUMO

Efficient repair of oxidized DNA is critical for genome-integrity maintenance. Cockayne syndrome protein B (CSB) is an ATP-dependent chromatin remodeler that collaborates with Poly(ADP-ribose) polymerase I (PARP1) in the repair of oxidative DNA lesions. How these proteins integrate during DNA repair remains largely unknown. Here, using chromatin co-fractionation studies, we demonstrate that PARP1 and PARP2 promote recruitment of CSB to oxidatively-damaged DNA. CSB, in turn, contributes to the recruitment of XRCC1, and histone PARylation factor 1 (HPF1), and promotes histone PARylation. Using alkaline comet assays to monitor DNA repair, we found that CSB regulates single-strand break repair (SSBR) mediated by PARP1 and PARP2. Strikingly, CSB's function in SSBR is largely bypassed when transcription is inhibited, suggesting CSB-mediated SSBR occurs primarily at actively transcribed DNA regions. While PARP1 repairs SSBs at sites regardless of the transcription status, we found that PARP2 predominantly functions in actively transcribed DNA regions. Therefore, our study raises the hypothesis that SSBR is executed by different mechanisms based on the transcription status.


Assuntos
Cromatina , Humanos , Proteínas de Transporte/genética , Cromatina/genética , DNA/genética , DNA/metabolismo , Reparo do DNA , Histonas/metabolismo , Proteínas Nucleares/metabolismo , Poli(ADP-Ribose) Polimerase-1/genética , Poli(ADP-Ribose) Polimerase-1/metabolismo , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/genética , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/metabolismo
2.
Scand J Immunol ; 98(2): e13275, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38441378

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic underlines a persistent threat of respiratory tract infectious diseases and warrants preparedness for a rapid response. At present, COVID-19 has had a serious social impact and imposed a heavy global burden on public health. The exact pathogenesis of COVID-19 has not been fully elucidated. Since the outbreak of COVID-19, a renewed attention has been brought to Toll-like receptors (TLRs). Available data and new findings have demonstrated that the interaction of human TLRs and SARS-CoV-2 is a vital mediator of COVID-19 immunopathogenesis. TLRs such as TLR2, 4, 7 and 8 are potentially important in viral combat and activation of immunity in patients with COVID-19. Therapeutics targeting TLRs are currently considered promising options against the pandemic. A number of TLR-targeting immunotherapeutics are now being investigated in preclinical studies and different phases of clinical trials. In addition, innovative vaccines based on TLRs under development could be a promising approach for building a new generation of vaccines to solve the current challenges. In this review, we summarize recent progress in the role of TLRs in COVID-19, focusing the new candidate drugs targeting TLRs, the current technology and potential paths forward for employing TLR agonists as vaccine adjuvants.


Assuntos
COVID-19 , Vacinas , Humanos , SARS-CoV-2 , Surtos de Doenças , Receptores Toll-Like
3.
Nucleic Acids Res ; 47(9): 4521-4538, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-30916347

RESUMO

Faithful propagation of transcription programs through cell division underlies cell-identity maintenance. Transcriptional regulators selectively bound on mitotic chromatin are emerging critical elements for mitotic transcriptional memory; however, mechanisms governing their site-selective binding remain elusive. By studying how protein-protein interactions impact mitotic chromatin binding of RBPJ, the major downstream effector of the Notch signaling pathway, we found that histone modifying enzymes HDAC1 and KDM5A play critical, regulatory roles in this process. We found that HDAC1 knockdown or inactivation leads to increased RBPJ occupancy on mitotic chromatin in a site-specific manner, with a concomitant increase of KDM5A occupancy at these sites. Strikingly, the presence of KDM5A is essential for increased RBPJ occupancy. Our results uncover a regulatory mechanism in which HDAC1 negatively regulates RBPJ binding on mitotic chromatin in a KDM5A-dependent manner. We propose that relative chromatin affinity of a minimal regulatory complex, reflecting a specific transcription program, renders selective RBPJ binding on mitotic chromatin.


Assuntos
Cromatina/genética , Histona Desacetilase 1/genética , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/genética , Proteína 2 de Ligação ao Retinoblastoma/genética , Animais , Sítios de Ligação , Sistemas CRISPR-Cas/genética , Ciclo Celular/genética , Divisão Celular/genética , Regulação da Expressão Gênica , Técnicas de Inativação de Genes , Humanos , Camundongos , Mitose/genética , Regiões Promotoras Genéticas , Ligação Proteica/genética , Transdução de Sinais/genética
4.
Nucleic Acids Res ; 46(15): 7471-7479, 2018 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-30032309

RESUMO

Cockayne syndrome protein B (CSB) is a member of the SNF2/SWI2 ATPase family and is essential for transcription-coupled nucleotide excision DNA repair (TC-NER). CSB also plays critical roles in transcription regulation. CSB can hydrolyze ATP in a DNA-dependent manner, alter protein-DNA contacts and anneal DNA strands. How the different biochemical activities of CSB are utilized in these cellular processes have only begun to become clear in recent years. Mutations in the gene encoding CSB account for majority of the Cockayne syndrome cases, which result in extreme sun sensitivity, premature aging features and/or abnormalities in neurology and development. Here, we summarize and integrate recent biochemical, structural, single-molecule and somatic cell genetic studies that have advanced our understanding of CSB. First, we review studies on the mechanisms that regulate the different biochemical activities of CSB. Next, we summarize how CSB is targeted to regulate transcription under different growth conditions. We then discuss recent advances in our understanding of how CSB regulates transcription mechanistically. Lastly, we summarize the various roles that CSB plays in the different steps of TC-NER, integrating the results of different studies and proposing a model as to how CSB facilitates TC-NER.


Assuntos
Síndrome de Cockayne/genética , DNA Helicases/genética , Enzimas Reparadoras do DNA/genética , Reparo do DNA/genética , Regulação da Expressão Gênica/genética , Proteínas de Ligação a Poli-ADP-Ribose/genética , Trifosfato de Adenosina/metabolismo , DNA/genética , Humanos , Mutação/genética , Schizosaccharomyces/genética , Transcrição Gênica/genética
5.
J Biol Chem ; 293(46): 17863-17874, 2018 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-30266807

RESUMO

Cockayne syndrome protein B (CSB) is an ATP-dependent chromatin remodeler that relieves oxidative stress by regulating DNA repair and transcription. CSB is proposed to participate in base-excision repair (BER), the primary pathway for repairing oxidative DNA damage, but exactly how CSB participates in this process is unknown. It is also unclear whether CSB contributes to other repair pathways during oxidative stress. Here, using a patient-derived CS1AN-sv cell line, we examined how CSB is targeted to chromatin in response to menadione-induced oxidative stress, both globally and locus-specifically. We found that menadione-induced, global CSB-chromatin association does not require CSB's ATPase activity and is, therefore, mechanistically distinct from UV-induced CSB-chromatin association. Importantly, poly(ADP-ribose) polymerase 1 (PARP1) enhanced the kinetics of global menadione-induced CSB-chromatin association. We found that the major BER enzymes, 8-oxoguanine DNA glycosylase (OGG1) and apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1), do not influence this association. Additionally, the level of γ-H2A histone family member X (γ-H2AX), a marker for dsDNA breaks, was not increased in menadione-treated cells. Therefore, our results support a model whereby PARP1 localizes to ssDNA breaks and recruits CSB to participate in DNA repair. Furthermore, this global CSB-chromatin association occurred independently of RNA polymerase II-mediated transcription elongation. However, unlike global CSB-chromatin association, both PARP1 knockdown and inhibition of transcription elongation interfered with menadione-induced CSB recruitment to specific genomic regions. This observation supports the hypothesis that CSB is also targeted to specific genomic loci to participate in transcriptional regulation in response to oxidative stress.


Assuntos
Cromatina/metabolismo , DNA Helicases/metabolismo , Enzimas Reparadoras do DNA/metabolismo , DNA/metabolismo , Estresse Oxidativo/fisiologia , Poli(ADP-Ribose) Polimerase-1/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Fator de Ligação a CCCTC/metabolismo , DNA/efeitos da radiação , Dano ao DNA , DNA Helicases/genética , Enzimas Reparadoras do DNA/genética , Loci Gênicos , Humanos , Mutação , Proteínas de Ligação a Poli-ADP-Ribose/genética , Ligação Proteica , Raios Ultravioleta , Vitamina K 3/farmacologia
6.
Nucleic Acids Res ; 45(8): 4696-4707, 2017 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-28369616

RESUMO

Cockayne syndrome protein B (CSB) belongs to the SWI2/SNF2 ATP-dependent chromatin remodeler family, and CSB is the only ATP-dependent chromatin remodeler essential for transcription-coupled nucleotide excision DNA repair. CSB alone remodels nucleosomes ∼10-fold slower than the ACF remodeling complex. Strikingly, NAP1-like histone chaperones interact with CSB and greatly enhance CSB-mediated chromatin remodeling. While chromatin remodeling by CSB and NAP1-like proteins is crucial for efficient transcription-coupled DNA repair, the mechanism by which NAP1-like proteins enhance chromatin remodeling by CSB remains unknown. Here we studied CSB's DNA-binding and nucleosome-remodeling activities at the single molecule level in real time. We also determined how the NAP1L1 chaperone modulates these activities. We found that CSB interacts with DNA in two principle ways: by simple binding and a more complex association that involves gross DNA distortion. Remarkably, NAP1L1 suppresses both these interactions. Additionally, we demonstrate that nucleosome remodeling by CSB consists of three distinct phases: activation, translocation and pausing, similar to ACF. Importantly, we found that NAP1L1 promotes CSB-mediated remodeling by accelerating both activation and translocation. Additionally, NAP1L1 increases CSB processivity by decreasing the pausing probability during translocation. Our study, therefore, uncovers the different steps of CSB-mediated chromatin remodeling that can be regulated by NAP1L1.


Assuntos
DNA Helicases/genética , Enzimas Reparadoras do DNA/genética , Chaperonas de Histonas/genética , Proteína 1 de Modelagem do Nucleossomo/genética , Transcrição Gênica , Trifosfato de Adenosina/metabolismo , Cromatina/genética , Montagem e Desmontagem da Cromatina/genética , Reparo do DNA/genética , Humanos , Nucleossomos/genética , Proteínas de Ligação a Poli-ADP-Ribose
7.
Mol Cell ; 37(2): 235-46, 2010 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-20122405

RESUMO

The ATP-dependent chromatin remodeler CSB is essential for transcription-coupled DNA repair, and mutations in CSB lead to Cockayne syndrome. Here, we examined the recruitment of CSB to chromatin after ultraviolet (UV) irradiation and uncovered a regulatory mechanism that ensures the specific association of this remodeler with chromatin. We demonstrate that ATP hydrolysis by CSB is essential for stable CSB-chromatin association after UV irradiation and that defects in this association underlie some forms of Cockayne syndrome. We also show that the N-terminal region of CSB negatively regulates chromatin association during normal cell growth. Of interest, in the absence of the negative regulatory region, ATP hydrolysis becomes dispensable for chromatin association, indicating that CSB uses energy from ATP hydrolysis to overcome the inhibitory effect imposed by its N-terminal region. Together, our results suggest that the recruitment of CSB to lesion-stalled transcription is an ATP-dependent process and involves a gross conformational change of CSB.


Assuntos
Trifosfato de Adenosina/metabolismo , Cromatina/metabolismo , DNA Helicases/fisiologia , Enzimas Reparadoras do DNA/fisiologia , Raios Ultravioleta , Adenosina Trifosfatases/fisiologia , Montagem e Desmontagem da Cromatina/fisiologia , Montagem e Desmontagem da Cromatina/efeitos da radiação , Síndrome de Cockayne/genética , DNA Helicases/genética , DNA Helicases/metabolismo , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Humanos , Modelos Genéticos , Proteínas de Ligação a Poli-ADP-Ribose
8.
Nucleic Acids Res ; 44(5): 2125-35, 2016 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-26578602

RESUMO

Cockayne syndrome is a premature aging disease associated with numerous developmental and neurological abnormalities, and elevated levels of reactive oxygen species have been found in cells derived from Cockayne syndrome patients. The majority of Cockayne syndrome cases contain mutations in the ATP-dependent chromatin remodeler CSB; however, how CSB protects cells from oxidative stress remains largely unclear. Here, we demonstrate that oxidative stress alters the genomic occupancy of the CSB protein and increases CSB occupancy at promoters. Additionally, we found that the long-range chromatin-structure regulator CTCF plays a pivotal role in regulating sites of genomic CSB occupancy upon oxidative stress. We show that CSB directly interacts with CTCF in vitro and that oxidative stress enhances the CSB-CTCF interaction in cells. Reciprocally, we demonstrate that CSB facilitates CTCF-DNA interactions in vitro and regulates CTCF-chromatin interactions in oxidatively stressed cells. Together, our results indicate that CSB and CTCF can regulate each other's chromatin association, thereby modulating chromatin structure and coordinating gene expression in response to oxidative stress.


Assuntos
Cromatina/química , DNA Helicases/genética , Enzimas Reparadoras do DNA/genética , DNA/genética , Fibroblastos/metabolismo , Proteínas Repressoras/genética , Sequência de Bases , Sítios de Ligação , Fator de Ligação a CCCTC , Linhagem Celular Transformada , Cromatina/efeitos dos fármacos , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , DNA/metabolismo , DNA Helicases/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Regulação da Expressão Gênica , Humanos , Dados de Sequência Molecular , Estresse Oxidativo , Proteínas de Ligação a Poli-ADP-Ribose , Ligação Proteica , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/metabolismo , Transdução de Sinais , Vitamina K 3/farmacologia
9.
RNA ; 21(12): 2053-66, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26437669

RESUMO

HnRNP L is a ubiquitous splicing-regulatory protein that is critical for the development and function of mammalian T cells. Previous work has identified a few targets of hnRNP L-dependent alternative splicing in T cells and has described transcriptome-wide association of hnRNP L with RNA. However, a comprehensive analysis of the impact of hnRNP L on mRNA expression remains lacking. Here we use next-generation sequencing to identify transcriptome changes upon depletion of hnRNP L in a model T-cell line. We demonstrate that hnRNP L primarily regulates cassette-type alternative splicing, with minimal impact of hnRNP L depletion on transcript abundance, intron retention, or other modes of alternative splicing. Strikingly, we find that binding of hnRNP L within or flanking an exon largely correlates with exon repression by hnRNP L. In contrast, exons that are enhanced by hnRNP L generally lack proximal hnRNP L binding. Notably, these hnRNP L-enhanced exons share sequence and context features that correlate with poor nucleosome positioning, suggesting that hnRNP may enhance inclusion of a subset of exons via a cotranscriptional or epigenetic mechanism. Our data demonstrate that hnRNP L controls inclusion of a broad spectrum of alternative cassette exons in T cells and suggest both direct RNA regulation as well as indirect mechanisms sensitive to the epigenetic landscape.


Assuntos
Epigênese Genética , RNA Mensageiro/metabolismo , Ribonucleoproteínas/fisiologia , Processamento Alternativo , Éxons , Humanos , Células Jurkat , Nucleossomos/metabolismo , RNA Mensageiro/genética , Transcriptoma
10.
PLoS Genet ; 10(3): e1004204, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24603501

RESUMO

Mechanisms that maintain transcriptional memory through cell division are important to maintain cell identity, and sequence-specific transcription factors that remain associated with mitotic chromatin are emerging as key players in transcriptional memory propagation. Here, we show that the major transcriptional effector of Notch signaling, RBPJ, is retained on mitotic chromatin, and that this mitotic chromatin association is mediated through the direct association of RBPJ with DNA. We further demonstrate that RBPJ binds directly to nucleosomal DNA in vitro, with a preference for sites close to the entry/exit position of the nucleosomal DNA. Genome-wide analysis in the murine embryonal-carcinoma cell line F9 revealed that roughly 60% of the sites occupied by RBPJ in asynchronous cells were also occupied in mitotic cells. Among them, we found that a fraction of RBPJ occupancy sites shifted between interphase and mitosis, suggesting that RBPJ can be retained on mitotic chromatin by sliding on DNA rather than disengaging from chromatin during mitotic chromatin condensation. We propose that RBPJ can function as a mitotic bookmark, marking genes for efficient transcriptional activation or repression upon mitotic exit. Strikingly, we found that sites of RBPJ occupancy were enriched for CTCF-binding motifs in addition to RBPJ-binding motifs, and that RBPJ and CTCF interact. Given that CTCF regulates transcription and bridges long-range chromatin interactions, our results raise the intriguing hypothesis that by collaborating with CTCF, RBPJ may participate in establishing chromatin domains and/or long-range chromatin interactions that could be propagated through cell division to maintain gene expression programs.


Assuntos
Cromatina/genética , DNA/genética , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/genética , Mitose/genética , Animais , Fator de Ligação a CCCTC , Humanos , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina/metabolismo , Interfase/genética , Camundongos , Nucleossomos/genética , Nucleossomos/metabolismo , Receptores Notch/genética , Receptores Notch/metabolismo , Proteínas Repressoras/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética
11.
PLoS Genet ; 10(4): e1004284, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24743307

RESUMO

Cockayne syndrome is an inherited premature aging disease associated with numerous developmental and neurological defects, and mutations in the gene encoding the CSB protein account for the majority of Cockayne syndrome cases. Accumulating evidence suggests that CSB functions in transcription regulation, in addition to its roles in DNA repair, and those defects in this transcriptional activity might contribute to the clinical features of Cockayne syndrome. Transcription profiling studies have so far uncovered CSB-dependent effects on gene expression; however, the direct targets of CSB's transcriptional activity remain largely unknown. In this paper, we report the first comprehensive analysis of CSB genomic occupancy during replicative cell growth. We found that CSB occupancy sites display a high correlation to regions with epigenetic features of promoters and enhancers. Furthermore, we found that CSB occupancy is enriched at sites containing the TPA-response element. Consistent with this binding site preference, we show that CSB and the transcription factor c-Jun can be found in the same protein-DNA complex, suggesting that c-Jun can target CSB to specific genomic regions. In support of this notion, we observed decreased CSB occupancy of TPA-response elements when c-Jun levels were diminished. By modulating CSB abundance, we found that CSB can influence the expression of nearby genes and impact nucleosome positioning in the vicinity of its binding site. These results indicate that CSB can be targeted to specific genomic loci by sequence-specific transcription factors to regulate transcription and local chromatin structure. Additionally, comparison of CSB occupancy sites with the MSigDB Pathways database suggests that CSB might function in peroxisome proliferation, EGF receptor transactivation, G protein signaling and NF-κB activation, shedding new light on the possible causes and mechanisms of Cockayne syndrome.


Assuntos
Cromatina/genética , DNA Helicases/genética , Enzimas Reparadoras do DNA/genética , Proteínas Proto-Oncogênicas c-jun/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica/genética , Linhagem Celular , Cromatina/metabolismo , Receptores ErbB/genética , Receptores ErbB/metabolismo , Proteínas de Ligação ao GTP/genética , Proteínas de Ligação ao GTP/metabolismo , Humanos , NF-kappa B/genética , NF-kappa B/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose , Regiões Promotoras Genéticas/genética
12.
Gastroenterology ; 149(7): 1872-1883.e9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26344056

RESUMO

BACKGROUND & AIMS: DNA structural lesions are prevalent in sporadic colorectal cancer. Therefore, we proposed that gene variants that predispose to DNA double-strand breaks (DSBs) would be found in patients with familial colorectal carcinomas of an undefined genetic basis (UFCRC). METHODS: We collected primary T cells from 25 patients with UFCRC and matched patients without colorectal cancer (controls) and assayed for DSBs. We performed exome sequence analyses of germline DNA from 20 patients with UFCRC and 5 undiagnosed patients with polyposis. The prevalence of identified variants in genes linked to DNA integrity was compared with that of individuals without a family history of cancer. The effects of representative variants found to be associated with UFCRC was confirmed in functional assays with HCT116 cells. RESULTS: Primary T cells from most patients with UFCRC had increased levels of the DSB marker γ(phosphorylated)histone2AX (γH2AX) after treatment with DNA damaging agents, compared with T cells from controls (P < .001). Exome sequence analysis identified a mean 1.4 rare variants per patient that were predicted to disrupt functions of genes relevant to DSBs. Controls (from public databases) had a much lower frequency of variants in the same genes (P < .001). Knockdown of representative variant genes in HCT116 CRC cells increased γH2AX. A detailed analysis of immortalized patient-derived B cells that contained variants in the Werner syndrome, RecQ helicase-like gene (WRN, encoding T705I), and excision repair cross-complementation group 6 (ERCC6, encoding N180Y) showed reduced levels of these proteins and increased DSBs, compared with B cells from controls. This phenotype was rescued by exogenous expression of WRN or ERCC6. Direct analysis of the recombinant variant proteins confirmed defective enzymatic activities. CONCLUSIONS: These results provide evidence that defects in suppression of DSBs underlie some cases of UFCRC; these can be identified by assays of circulating lymphocytes. We specifically associated UFCRC with variants in WRN and ERCC6 that reduce the capacity for repair of DNA DSBs. These observations could lead to a simple screening strategy for UFCRC, and provide insight into the pathogenic mechanisms of colorectal carcinogenesis.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias Colorretais/genética , Quebras de DNA de Cadeia Dupla , Variação Genética , Linfócitos T/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/metabolismo , Estudos de Casos e Controles , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Biologia Computacional , DNA Helicases/genética , DNA Helicases/metabolismo , Reparo do DNA , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Bases de Dados Genéticas , Exodesoxirribonucleases/genética , Exodesoxirribonucleases/metabolismo , Exoma , Feminino , Frequência do Gene , Técnicas de Silenciamento de Genes , Predisposição Genética para Doença , Instabilidade Genômica , Células HCT116 , Hereditariedade , Histonas/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Mutagênicos/farmacologia , Fenótipo , Fosforilação , Proteínas de Ligação a Poli-ADP-Ribose , RecQ Helicases/genética , RecQ Helicases/metabolismo , Análise de Sequência de DNA , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Transfecção , Regulação para Cima , Helicase da Síndrome de Werner
13.
PLoS Genet ; 9(4): e1003407, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23637612

RESUMO

The Cockayne syndrome complementation group B (CSB) protein is essential for transcription-coupled DNA repair, and mutations in CSB are associated with Cockayne syndrome--a devastating disease with complex clinical features, including the appearance of premature aging, sun sensitivity, and numerous neurological and developmental defects. CSB belongs to the SWI2/SNF2 ATP-dependent chromatin remodeler family, but the extent to which CSB remodels chromatin and whether this activity is utilized in DNA repair is unknown. Here, we show that CSB repositions nucleosomes in an ATP-dependent manner in vitro and that this activity is greatly enhanced by the NAP1-like histone chaperones, which we identify as new CSB-binding partners. By mapping functional domains and analyzing CSB derivatives, we demonstrate that chromatin remodeling by the combined activities of CSB and the NAP1-like chaperones is required for efficient transcription-coupled DNA repair. Moreover, we show that chromatin remodeling and repair protein recruitment mediated by CSB are separable activities. The collaboration that we observed between CSB and the NAP1-like histone chaperones adds a new dimension to our understanding of the ways in which ATP-dependent chromatin remodelers and histone chaperones can regulate chromatin structure. Taken together, the results of this study offer new insights into the functions of chromatin remodeling by CSB in transcription-coupled DNA repair as well as the underlying mechanisms of Cockayne syndrome.


Assuntos
Montagem e Desmontagem da Cromatina , Síndrome de Cockayne , Trifosfato de Adenosina/metabolismo , Síndrome de Cockayne/genética , DNA Helicases/genética , Reparo do DNA , Enzimas Reparadoras do DNA/genética , Chaperonas de Histonas/genética , Humanos , Transcrição Gênica
14.
Neurotherapeutics ; 21(3): e00342, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38493057

RESUMO

Novel therapeutics for the treatment of ischemic stroke remains to be the unmet clinical needs. Previous studies have indicated that salvianolic acid A (SAA) is a promising candidate for the treatment of the brain diseases. However, SAA has poor absolute bioavailability and does not efficiently cross the intact blood-brain barrier (BBB), which limit its efficacy. To this end we developed a brain-targeted liposomes for transporting SAA via the BBB by incorporating the liposomes to a transport receptor, insulin-like growth factor-1 receptor (IGF1R). The liposomes were prepared by ammonium sulfate gradients loading method. The prepared SAA-loaded liposomes (Lipo/SAA) were modified with IGF1R monoclonal antibody to generate IGF1R antibody-conjugated Lipo/SAA (IGF1R-targeted Lipo/SAA). The penetration of IGF1R-targeted Lipo/SAA into the brain was confirmed by labeling with Texas Red, and their efficacy were evaluate using middle cerebral artery occlusion (MCAO) model. The results showed that IGF1R-targeted Lipo/SAA are capable of transporting SAA across the BBB into the brain, accumulation in brain tissue, and sustained releasing SAA for several hours. Administration o IGF1R-targeted Lipo/SAA notably reduced infarct size and neuronal damage, improved neurological function and inhibited cerebral inflammation, which had much higher efficiency than no-targeted SAA.


Assuntos
AVC Isquêmico , Lipossomos , Animais , AVC Isquêmico/tratamento farmacológico , Masculino , Ácidos Cafeicos/administração & dosagem , Ácidos Cafeicos/química , Ácidos Cafeicos/farmacologia , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Receptor IGF Tipo 1/metabolismo , Camundongos , Lactatos/administração & dosagem , Lactatos/química , Infarto da Artéria Cerebral Média/tratamento farmacológico , Sistemas de Liberação de Medicamentos/métodos , Ratos Sprague-Dawley , Ratos , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos
15.
J Steroid Biochem Mol Biol ; : 106628, 2024 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-39448043

RESUMO

To date, glucocorticoids remain the mainstay of treatment of nephrotic syndrome (NS). However, serious side effects and development of drug-resistance following long-term use limit the application of glucocorticoids. Protopanaxadiol (PPD) possesses activity of dissociating transactivation from transrepression by glucocorticoid receptor (GR), which may serve as a potential selective GR modulator. However, steroid-like effects of PPD in vivo are unclear and not defined. How to translate PPD into clinical practice remains to be explored. The current study explored the renoprotection and potential mechanism of PPD and its combination with steroid hormones using adriamycin-induced NS rats. Adriamycin was given intravenously to rats to induce nephropathy. The determination of proteinuria, biochemical changes and inflammatory cytokines were performed, and pathological changes were examined by histopathological examination. Immunostaining and PCR were used to analyze the expression of interesting proteins and genes. The results showed that PPD, alone and in combination with prednisone, efficiently alleviate the symptoms of NS, attenuate nephropathy, improve adriamycin-induced podocyte injury by reducing desmin and increasing synaptopodin expression. In addition, the combined treatment reduced the expression of NF-κB protein and mRNA, as well as cytokine levels, and yet increased the expression of GR protein and mRNA. PPD modulated the transactivation of GR, manifested as repressing TAT, PEPCK and ANGPTL4 mRNA expressions mediated by GR. Meanwhile, PPD inhibited elevation of blood glucose and immune organ atrophy induced by prednisone. In summary, PPD increases the therapeutic effect of prednisone in NS while effectively prevents or decreases the appearance of side effects of glucocorticoids.

16.
Naunyn Schmiedebergs Arch Pharmacol ; 397(11): 8707-8723, 2024 11.
Artigo em Inglês | MEDLINE | ID: mdl-38829385

RESUMO

Garlic exhibits hypolipidemic, hypoglycemic, and cardiovascular benefits. The inconsistent results of garlic preparations on adipogenesis have caused more confusion in the public and academia. The compounds responsible for the anti-adipogenesis effect of garlic remain unknown. The present study aimed to verify the real anti-adipogenesis and anti-obesity component in garlic and explored its possible effects in metabolic syndrome. We verified the real anti-adipogenesis and anti-obesity components of garlic in 3T3-L1 preadipocytes and a 10-week-high fat diet (HFD)-induced obese mice. In vitro, two water-soluble and four typical lipid-soluble compounds of garlic were tested for their anti-adipogenesis. Then, the water-soluble compound, alliin, and two processing methods produced garlic oils, were evaluated in vivo study. Mice received oral administration of alliin (25 mg/kg) and garlic oils (15 mg/kg) daily for 8 weeks. Serum lipids, parameters of obesity, and indicators involved in regulating glycolipid metabolism were examined. Our findings confirmed that both water-soluble and lipid-soluble organosulfur compounds of garlic contributed to garlic's anti-adipogenesis effect, in which water-soluble sulfides, especially alliin, exhibited greater potency. Alliin possessed potent effects of anti-obesity and improvement in glucose and lipid metabolism in HFD-induced obese mice. Alliin mediated these effects partly attributed to its modulation of enzymatic activities within glycolipid metabolism and activating PPARγ signaling pathway. In contrast to odorous lipid-soluble sulfides, alliin is odorless, stable, and safe, and is an ideal nutraceutical or even medicinal candidates for the treatment of metabolic diseases. Alliin could be used to standardize the quality of garlic products.


Assuntos
Células 3T3-L1 , Adipogenia , Fármacos Antiobesidade , Dieta Hiperlipídica , Alho , Glicolipídeos , Obesidade , PPAR gama , Transdução de Sinais , Animais , Fármacos Antiobesidade/farmacologia , Fármacos Antiobesidade/uso terapêutico , Camundongos , Adipogenia/efeitos dos fármacos , PPAR gama/metabolismo , Glicolipídeos/farmacologia , Masculino , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Transdução de Sinais/efeitos dos fármacos , Dieta Hiperlipídica/efeitos adversos , Camundongos Endogâmicos C57BL , Sulfetos/farmacologia , Sulfetos/uso terapêutico , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Cisteína/análogos & derivados
17.
Nat Prod Res ; : 1-6, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38251834

RESUMO

Two new protopanaxadiol type sapogenins, (3ß,12ß)-3,12,20-trihydroxydammar-24-en-26-al (1) and (3ß,12ß)-3,12,20-trihydroxydammar-24-en-26-oic acid (2), were isolated from the alkali hydrolysate of stems-leaves of Panax notoginseng, along with seven known analogues (3-9). Their structures were elucidated by spectroscopic analyses and single-crystal X-ray diffraction. Compound 2 and the known sapogenins 5-8 displayed weak to moderate inhibition of NO production in LPS-induced RAW264.7 macrophages with IC50 values from 44.5 to 143.6 µM, respectively.

18.
Heliyon ; 9(3): e13991, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36923858

RESUMO

Objective: To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate acupuncture's clinical effect on insulin resistance (IR) in women with polycystic ovary syndrome (PCOS). Methods: PubMed, Cochrane Library, Embase databases, and Chinese databases, including China National Knowledge Infrastructure, Technology Journal Database, and Wanfang Database, were searched without language restrictions from inception to December 20, 2021. Only RCTs in which acupuncture had been examined as the sole or adjunctive PCOS-IR treatment were included. Our primary endpoint was the homeostasis model assessment of insulin resistance (HOMA-IR). The secondary outcomes were fasting blood glucose (FBG), fasting insulin (FINS), body mass index (BMI), and adverse events. Results: Our analysis included 17 eligible RCTs (N = 1511 participants). Compared with other treatments, acupuncture therapy yielded a greater mean reduction in HOMA-IR (MD = -0.15; 95% CI, -0.27 to -0.03; P = 0.01) and BMI (MD = -1.47; 95% CI, -2.46 to -0.47; P = 0.004). Besides acupuncture was associated with a lower risk of adverse events than other treatments (RR, 0.15; 95% CI, 0.10 to 0.22; P < 0.01). Additionally, the combination treatment of acupuncture and medicine is more effective in improving HOMA-IR (MD = -0.91; 95% CI, -1.11 to -0.71; P < 0.01), FBG (MD = -0.30; 95% CI, -0.56 to -0.04; P = 0.02), FINS (MD = -2.33; 95% CI, -2.60 to -2.06; P < 0.01) and BMI (MD = -1.63; 95% CI, -1.94 to -1.33; P < 0.01) than medicine alone. Conclusions: Acupuncture is relatively effective in improving HOMA-IR and BMI in PCOS-IR. Besides, it's safer than other treatments and could be an adjuvant strategy for improving PCOS-IR. Further large-scale, long-term RCTs with strict methodological standards are justified.

19.
J Pharm Pharmacol ; 75(5): 693-702, 2023 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-36964741

RESUMO

OBJECTIVES: Nephrotic syndrome (NS) remains a therapeutic challenge for nephrologists. Piceatannol-3'-O-ß-d-glucopyranoside (PG) is a major active ingredient in Quzha. The purpose of the study was to assess the renoprotection of PG. METHODS: In vitro, the podocyte protection of PG was assessed in MPC-5. SD rats were injected with adriamycin to induce nephropathy in vivo. The determination of biochemical changes and inflammatory cytokines was performed, and pathological changes were examined by histopathological examination. Immunostaining and western blot analyses were used to analyse expression levels of proteins. KEY FINDINGS: The results showed that PG improved adriamycin-induced podocyte injury, attenuated nephropathy, improved hypoalbuminemia and hyperlipidaemia, and lowered cytokine levels. The podocyte protection of PG was further verified by reduction of desmin and increasing synaptopodin expression. Furthermore, treatment with PG down-regulated the expression of HMGB1, TLR4 and NF-κB along with its upstream regulator, IKKß and yet up-regulated IκBα expression by western blot analysis. CONCLUSIONS: Overall, our data showed that PG has a favourable renoprotection in experimental nephrosis, apparently by amelioration of podocyte injury. PG might mediate these effects via modulation of the HMGB1/TLR4/NF-κB signalling pathway. The study first provides a promising leading compound for the treatment of NS.


Assuntos
Proteína HMGB1 , NF-kappa B , Transdução de Sinais , Animais , Ratos , Citocinas , Doxorrubicina , NF-kappa B/metabolismo , Ratos Sprague-Dawley , Receptor 4 Toll-Like/metabolismo
20.
J Biol Chem ; 286(40): 34951-8, 2011 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-21852235

RESUMO

The Cockayne syndrome complementation group B (CSB) protein is an ATP-dependent chromatin remodeler with an essential function in transcription-coupled DNA repair, and mutations in the CSB gene are associated with Cockayne syndrome. The p53 tumor suppressor has been known to interact with CSB, and both proteins have been implicated in overlapping biological processes, such as DNA repair and aging. The significance of the interaction between CSB and p53 has remained unclear, however. Here, we show that the chromatin association of CSB and p53 is inversely related. Using in vitro binding and chromatin immunoprecipitation approaches, we demonstrate that CSB facilitates the sequence-independent association of p53 with chromatin when p53 concentrations are low and that this is achieved by the interaction of CSB with the C-terminal region of p53. Remarkably, p53 prevents CSB from binding to nucleosomes when p53 concentrations are elevated. Examining the enzymatic properties of CSB revealed that p53 excludes CSB from nucleosomes by occluding a nucleosome interaction surface on CSB. Together, our results suggest that the reciprocal regulation of chromatin access by CSB and p53 could be part of a mechanism by which these two proteins coordinate their activities to regulate DNA repair, cell survival, and aging.


Assuntos
DNA Helicases/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Regulação da Expressão Gênica , Proteína Supressora de Tumor p53/metabolismo , Trifosfato de Adenosina/metabolismo , Apoptose , Sobrevivência Celular , Senescência Celular , Cromatina/metabolismo , Síndrome de Cockayne/genética , Reparo do DNA , Fibroblastos/metabolismo , Teste de Complementação Genética , Genoma , Humanos , Modelos Biológicos , Modelos Genéticos , Nucleossomos/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose
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