Serum Concentrations of Infliximab and IL-6 for Predicting One-Year Discontinuation of Infliximab Treatment Owing to Secondary Non-response in Patients with Rheumatoid Arthritis.

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.

Self-organization, quality control, and preclinical studies of human iPSC-derived retinal sheets for tissue-transplantation therapy.

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.

H3K36ac Is an Evolutionary Conserved Plant Histone Modification That Marks Active Genes.

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.

The role of Arabidopsis thaliana NAR1, a cytosolic iron-sulfur cluster assembly component, in gametophytic gene expression and oxidative stress responses in vegetative tissue.

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.

Canine bone marrow cells differentiate into hepatocyte-like cells and placental hydrolysate is a potential inducer.

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.

A novel ferredoxin-dependent glutamate synthase from the hydrogen-oxidizing chemoautotrophic bacterium Hydrogenobacter thermophilus TK-6.

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.

Monoclonal antibody to stage-specific fetal brain 68-kDa glycoprotein (FGP68) revealed increased FGP68 expression in human primary brain tumors.

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.