RESUMO
Secondary non-response to infliximab (IFX) occurs in some patients with rheumatoid arthritis (RA). Although therapeutic drug monitoring (TDM) is a useful tool to optimize IFX therapy, it is unclear whether it can help to identify the risk of secondary non-response. This study aimed to explore the utility of serum levels of IFX or other biomarkers to predict IFX discontinuation owing to secondary non-response. A single-center, retrospective study was conducted using the Kyoto University Rheumatoid Arthritis Management Alliance cohort database between 2011 and 2020. Serum IFX levels were measured using liquid chromatography-tandem mass spectrometry. An electrochemiluminescence assay was used to quantify serum levels of tumor necrosis factor-α and interleukin-6 and detect anti-drug antibodies. Eighty-four out of 310 patients were eligible for this study. The cutoff levels of biomarkers were determined by receiver operating characteristic analysis. IFX persistence was similar between groups stratified using IFX levels, tumor necrosis factor-α levels, interleukin-6 levels, and anti-drug antibodies positivity. The group with lower IFX and higher interleukin-6 levels had the worst therapy persistence (p = 0.017) and the most frequent disease worsening (90.0%, p < 0.001). Evaluating both interleukin-6 and IFX levels, not just IFX alone, enabled us to identify patients at risk of discontinuing IFX treatment. These findings support the utility of measuring IFX and interleukin-6 levels for successful maintenance therapy for RA.
Assuntos
Antirreumáticos , Artrite Reumatoide , Infliximab , Interleucina-6 , Humanos , Anticorpos/sangue , Antirreumáticos/uso terapêutico , Artrite Reumatoide/tratamento farmacológico , Biomarcadores , Infliximab/uso terapêutico , Interleucina-6/sangue , Estudos Retrospectivos , Fator de Necrose Tumoral alfaRESUMO
Three-dimensional retinal organoids (3D-retinas) are a promising graft source for transplantation therapy. We previously developed self-organizing culture for 3D-retina generation from human pluripotent stem cells (hPSCs). Here we present a quality control method and preclinical studies for tissue-sheet transplantation. Self-organizing hPSCs differentiated into both retinal and off-target tissues. Gene expression analyses identified the major off-target tissues as eye-related, cortex-like, and spinal cord-like tissues. For quality control, we developed a qPCR-based test in which each hPSC-derived neuroepithelium was dissected into two tissue-sheets: inner-central sheet for transplantation and outer-peripheral sheet for qPCR to ensure retinal tissue selection. During qPCR, tissue-sheets were stored for 3-4 days using a newly developed preservation method. In a rat tumorigenicity study, no transplant-related adverse events were observed. In retinal degeneration model rats, retinal transplants differentiated into mature photoreceptors and exhibited light responses in electrophysiology assays. These results demonstrate our rationale toward self-organizing retinal sheet transplantation therapy.
Assuntos
Células-Tronco Pluripotentes Induzidas , Células-Tronco Pluripotentes , Degeneração Retiniana , Humanos , Ratos , Animais , Retina/metabolismo , Degeneração Retiniana/terapia , Degeneração Retiniana/metabolismo , Células FotorreceptorasRESUMO
In eukaryotic cells, histones are subject to a large number of posttranslational modifications whose sequential or combinatorial action affects chromatin structure and genome function. We identified acetylation at Lys-36 in histone H3 (H3K36ac) as a new chromatin modification in plants. The H3K36ac modification is evolutionary conserved in seed plants, including the gymnosperm Norway spruce (Picea abies) and the angiosperms rice (Oryza sativa), tobacco (Nicotiana tabacum), and Arabidopsis (Arabidopsis thaliana). In Arabidopsis, H3K36ac is highly enriched in euchromatin but not in heterochromatin. Genome-wide chromatin immunoprecipitation sequencing experiments revealed that H3K36ac peaks at the 5' end of genes, mainly on the two nucleosomes immediately distal to the transcription start site, independently of gene length. H3K36ac overlaps with H3K4me3 and the H2A.Z histone variant. The histone acetyl transferase GCN5 and the histone deacetylase HDA19 are required for H3K36ac homeostasis. H3K36ac and H3K36me3 show negative crosstalk, which is mediated by GCN5 and the histone methyl transferase SDG8. Although H3K36ac is associated with gene activity, we did not find a linear relationship between H3K36ac and transcript levels, suggesting that H3K36ac is a binary indicator of transcription.
Assuntos
Código das Histonas/genética , Histonas/metabolismo , Lisina/metabolismo , Proteínas de Plantas/metabolismo , Processamento de Proteína Pós-Traducional , Acetilação , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Cromossomos de Plantas/genética , Sequência Conservada/genética , Evolução Molecular , Regulação da Expressão Gênica de Plantas , Genoma de Planta/genética , Histona Acetiltransferases/genética , Histona Acetiltransferases/metabolismo , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Histonas/genética , Lisina/genética , Oryza/genética , Oryza/metabolismo , Picea/genética , Picea/metabolismo , Proteínas de Plantas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Nicotiana/genética , Nicotiana/metabolismo , Sítio de Iniciação de TranscriçãoRESUMO
Iron-sulfur proteins have iron-sulfur clusters as a prosthetic group and are responsible for various cellular processes, including general transcriptional regulation, photosynthesis and respiration. The cytosolic iron-sulfur assembly (CIA) pathway of yeast has been shown to be responsible for regulation of iron-sulfur cluster assembly in both the cytosol and the nucleus. However, little is known about the roles of this pathway in multicellular organisms. In a forward genetic screen, we identified an Arabidopsis thaliana mutant with impaired expression of the endosperm-specific gene Flowering Wageningen (FWA). To characterize this mutant, we carried out detailed phenotypic and genetic analyses during reproductive and vegetative development. The mutation affects NAR1, which encodes a homolog of a yeast CIA pathway component. Comparison of embryo development in nar1-3 and other A. thaliana mutants affected in the CIA pathway showed that the embryos aborted at a similar stage, suggesting that this pathway potentially functions in early seed development. Transcriptome analysis of homozygous viable nar1-4 seedlings showed transcriptional repression of a subset of genes involved in 'iron ion transport' and 'response to nitrate'. nar1-4 also exhibited resistance to the herbicide paraquat. Our results indicate that A. thaliana NAR1 has various functions including transcriptional regulation in gametophytes and abiotic stress responses in vegetative tissues.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Citosol/metabolismo , Células Germinativas Vegetais/metabolismo , Proteínas Ferro-Enxofre/metabolismo , Estresse Oxidativo/genética , Aconitato Hidratase/metabolismo , Alelos , Arabidopsis/citologia , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Cruzamentos Genéticos , Endosperma/citologia , Endosperma/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Impressão Genômica , Células Germinativas Vegetais/citologia , Proteínas de Fluorescência Verde/metabolismo , Heterozigoto , Proteínas Ferro-Enxofre/genética , Mutação/genética , Paraquat/toxicidade , Fenótipo , Polinização , Proteínas Recombinantes de Fusão/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sementes/embriologia , Sementes/metabolismoRESUMO
Hepatocyte growth factor (HGF) can stimulate human and rat bone marrow (BM) cells to differentiate into hepatocytes. A human placental hydrolysate (hPH) stimulates proliferation of hepatocytes, but its role as a potential inducer of BM cells to form hepatocytes is unclear. To determine if canine BM cells stimulated with HGF or hPH differentiate into hepatocyte-like cells, BM cells were cultured with HGF or hPH. The cultured cells underwent morphological examination, expression of albumin and cytokeratin 18 (CK18), hepatic function tests including uptake of low-density lipoprotein (LDL) and cytochrome P (CYP) 450 activity. Albumin mRNA and protein expression of albumin and CK18 proteins were detected in cultures with HGF and hPH. Furthermore, these cells demonstrated LDL uptake and CYP450 activity. These results indicate that canine BM cells can differentiate into hepatocyte-like cells when stimulated by both HGF and that hPH may be an effective inducer of hepatic differentiation.
Assuntos
Células da Medula Óssea/citologia , Células da Medula Óssea/efeitos dos fármacos , Cães , Fator de Crescimento de Hepatócito/farmacologia , Hepatócitos/fisiologia , Placenta , Albuminas/genética , Albuminas/metabolismo , Animais , Células Cultivadas , Sistema Enzimático do Citocromo P-450/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Hepatócitos/citologia , Humanos , Hidrólise , Lipoproteínas LDL/metabolismo , Proteínas Proto-Oncogênicas c-met/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Glutamate synthases are classified according to their specificities for electron donors. Ferredoxin-dependent glutamate synthases had been found only in plants and cyanobacteria, whereas many bacteria have NADPH-dependent glutamate synthases. In this study, Hydrogenobacter thermophilus, a hydrogen-oxidizing chemoautotrophic bacterium, was shown to possess a ferredoxin-dependent glutamate synthase like those of phototrophs. This is the first observation, to our knowledge, of a ferredoxin-dependent glutamate synthase in a nonphotosynthetic organism. The purified enzyme from H. thermophilus was shown to be a monomer of a 168-kDa polypeptide homologous to ferredoxin-dependent glutamate synthases from phototrophs. In contrast to known ferredoxin-dependent glutamate synthases, the H. thermophilus glutamate synthase exhibited glutaminase activity. Furthermore, this glutamate synthase did not react with a plant-type ferredoxin (Fd3 from this bacterium) containing a [2Fe-2S] cluster but did react with bacterial ferredoxins (Fd1 and Fd2 from this bacterium) containing [4Fe-4S] clusters. Interestingly, the H. thermophilus glutamate synthase was activated by some of the organic acids in the reductive tricarboxylic acid cycle, the central carbon metabolic pathway of this organism. This type of activation has not been reported for any other glutamate synthases, and this property may enable the control of nitrogen assimilation by carbon metabolism.
Assuntos
Bactérias/enzimologia , Ferredoxinas/metabolismo , Glutamato Sintase/metabolismo , Bactérias/classificação , Bactérias/genética , Proteínas de Bactérias/metabolismo , Primers do DNA , Espectroscopia de Ressonância de Spin Eletrônica , Glutamato Sintase/genética , Glutamato Sintase/isolamento & purificação , Hidrogênio/metabolismo , Cinética , Dados de Sequência Molecular , Filogenia , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , EspectrofotometriaRESUMO
We have produced a novel rat IgG(2a) monoclonal antibody against a stage-specific fetal brain glycoprotein of 68 kDa (FGP68), and succeeded in applying it to staining paraffin sections. To gain some insight into the pathobiological significance of this FGP68, this monoclonal antibody was used in immunohistochemical studies to compare the expression of FGP68 and Ki-67 antigen (MIB-1) in 235 primary brain tumors. Approximately half of the glioblastomas multiforme (GBMs) (44/75) and anaplastic astrocytomas (9/17) as well as some astrocytomas (5/30), medulloblastomas (2/14) and primitive neuroectodermal tumors (2/10) had tumor cells that expressed FGP68; however, pilocytic astrocytomas (0/7), oligodendrogliomas (0/15), ependymomas (0/6), schwannomas (0/21), meningiomas (0/22) and pituitary adenomas (0/18) did not express FGP68. The values of the MIB-1 labeling index were statistically higher in GBMs (0.005< P<0.01, Wilcoxon rank-sum test) and anaplastic astrocytomas (0.025< P<0.05) that expressed FGP68 than in those that did not. Normal brain tissue from 20 individuals aged 3-75 years was negative for FGP68 and MIB-1. We conclude that primary brain tumors express FGP68, one of the oncofetal proteins derived from fetal brain, and that FGP68 expression in certain brain tumor cells may depend, in part, on proliferation potential. Based on the possibility that the stage-specific FGP68 plays an important role in brain embryogenesis, some of FGP68-expressing tumor cells might phylogenetically revert to more primitive cells.