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Canine gastrointestinal lymphoma is known to be of T-cell origin in most cases, but the molecular biological aberrations have not been clarified. In human intestinal T-cell lymphoma, the mutations in the genes associated with Janus kinase/signal transducer and activator of transcription (JAK-STAT) pathway have been frequently observed. In this study, the gene mutations were investigated in 31 dogs with large cell gastrointestinal lymphoma (LCGIL) by focusing on the genes involved in JAK-STAT pathway. Next-generation sequencing analysis to examine the mutations in STAT3, STAT5B, and JAK1 genes throughout the exon regions revealed the mutations in STAT3 gene in two dogs and JAK1 gene in one dog. In conclusion, this study could not indicate the associations of gene mutations in JAK-STAT pathway with LCGIL in most canine cases.

Introduction: In human placental development, the trophectoderm (TE) appears in blastocysts on day 5 post-fertilization and develops after implantation into three types of trophoblast lineages: cytotrophoblast (CT), syncytiotrophoblast (ST), and extravillous trophoblast (EVT). CDX2/Cdx2 is expressed in the TE, and Cdx2 expression is upregulated by knockdown of Foxo1 in mouse ESCs. However, the significance of FOXO1 in trophoblast lineage differentiation during the early developmental period remains unclear. In this study, we examined the effect of FOXO1 inhibition on the differentiation of naive human induced pluripotent stem cells (iPSCs) into TE and trophoblast lineages., Methods: We induced TE differentiation from naive iPSCs in the presence or absence of a FOXO1 inhibitor, and the resulting cells were subjected to trophoblast differentiation procedures without the FOXO1 inhibitor. The cells obtained in these processes were assessed for morphology, gene expression, and hCG secretion using phase-contrast microscopy, reverse transcription polymerase chain reaction (RT-PCR), quantitative RT-PCR (RT-qPCR), RNA-seq, immunochromatography, and a chemiluminescent enzyme immunoassay., Results: In the induction of trophoblast differentiation from naive iPSCs, treatment with a FOXO1 inhibitor resulted in the enhanced expression of TE markers, CDX2 and HAND1, but conversely decreased the expression of ST markers, such as ERVW1 (Syncytin-1) and GCM1, and an EVT marker, HLA-G. The proportion of cells positive for an early TE marker TACSTD2 and negative for a late TE marker ENPEP was higher in FOXO1 inhibitor-treated cells than in non-treated cells. The expressions of ERVW1 (Syncytin-1), ERVFRD-1 (Syncytin-2), and other endogenous retrovirus (ERV)-associated genes that have been reported to be expressed in trophoblasts were suppressed in the cells obtained by differentiating the TE cells treated with FOXO1 inhibitor., Conclusions: Treatment with a FOXO1 inhibitor during TE induction from naive iPSCs promotes early TE differentiation but hinders the progression of differentiation into ST and EVT. The suppression of ERV-associated genes may be involved in this process., Competing Interests: The authors have no competing financial interests to declare., (© 2024 The Author(s).)

Background: Xeroderma pigmentosum (XP) is characterized by photosensitivity that causes pigmentary disorder and predisposition to skin cancers on sunlight-exposed areas due to DNA repair deficiency. Patients with XP group A (XP-A) develop freckle-like pigmented maculae and depigmented maculae within a year unless strict sun-protection is enforced. Although it is crucial to study pigment cells (melanocytes: MCs) as disease target cells, establishing MCs in primary cultures is challenging., Objective: Elucidation of the disease pathogenesis by comparison between MCs differentiated from XP-A induced pluripotent stem cells (iPSCs) and healthy control iPSCs on the response to UV irradiation., Methods: iPSCs were established from a XP-A fibroblasts and differentiated into MCs. Differences in gene expression profiles between XP-A-iPSC-derived melanocytes (XP-A-iMCs) and Healthy control iPSC-derived MCs (HC-iMCs) were analyzed 4 and 12 h after irradiation with 30 or 150 J/m 2 of UV-B using microarray analysis., Results: XP-A-iMCs expressed SOX10, MITF, and TYR, and showed melanin synthesis. Further, XP-A-iMCs showed reduced DNA repair ability. Gene expression profile between XP-A-iMCs and HC-iMCs revealed that, numerous gene probes that were specifically upregulated or downregulated in XP-A-iMCs after 150-J/m 2 of UV-B irradiation did not return to basal levels. Of note that apoptotic pathways were highly upregulated at 150 J/m 2 UV exposure in XP-A-iMCs, and cytokine-related pathways were upregulated even at 30 J/m 2 UV exposure., Conclusion: We revealed for the first time that cytokine-related pathways were upregulated even at low-dose UV exposure in XP-A-iMCs. Disease-specific iPSCs are useful to elucidate the disease pathogenesis and develop treatment strategies of XP., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2024 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

Human pluripotent stem cells, such as human embryonic stem cells and human induced pluripotent stem cells, are used in basic research and various applied fields, including drug discovery and regenerative medicine. Stem cell technologies have developed rapidly in recent years, and the supply of culture materials has improved. This has facilitated the culture of human pluripotent stem cells and has enabled an increasing number of researchers and bioengineers to access this technology. At the same time, it is a challenge to share the basic concepts and techniques of this technology among researchers and technicians to ensure the reproducibility of research results. Human pluripotent stem cells differ from conventional somatic cells in many aspects, and many points need to be considered in their handling, even for those experienced in cell culture. Therefore, we have prepared this proposal, "Points of Consideration for Pluripotent Stem Cell Culture," to promote the effective use of human pluripotent stem cells. This proposal includes seven items to be considered and practices to be confirmed before using human pluripotent stem cells. These are laws/guidelines and consent/material transfer agreements, diversity of pluripotent stem cells, culture materials, thawing procedure, media exchange and cell passaging, freezing procedure, and culture management. We aim for the concept of these points of consideration to be shared by researchers and technicians involved in the cell culture of pluripotent stem cells. In this way, we hope the reliability of research using pluripotent stem cells can be improved, and cell culture technology will advance., (© 2024. The Author(s).)

This study highlights the novel potential of molecular aggregates as inhibitors of a disease-related protein. Enzyme inhibitors have been studied and developed as molecularly targeted drugs and have been applied for cancer, autoimmune diseases, and infections. In many cases, enzyme inhibitors that are used for therapeutic applications interact directly with enzymes in a molecule-to-molecule manner. We found that the aggregates of a small compound, Mn007, inhibited bovine pancreatic DNase I. Once Mn007 molecules formed aggregates, they exhibited inhibitory effects specific to DNases that require divalent metal ions. A DNase secreted by Streptococcus pyogenes causes streptococcal toxic shock syndrome (STSS). STSS is a severe infectious disease with a fatality rate exceeding 30% in patients, even in this century. S. pyogenes disrupts the human barrier system against microbial infections through the secreted DNase. Until now, the discovery/development of a DNase inhibitor has been challenging. Mn007 aggregates were found to inhibit the DNase secreted by S. pyogenes , which led to the successful suppression of S. pyogenes growth in human whole blood. To date, molecular aggregation has been outside the scope of drug discovery. The present study suggests that molecular aggregation is a vast area to be explored for drug discovery and development because aggregates of small-molecule compounds can inhibit disease-related enzymes., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

With the progression of regenerative medicine and cell therapy, the importance of cryopreservation techniques for cultured cells continues to rise. Traditional cryoprotectants, such as dimethyl sulfoxide and glycerol, are effective in cryopreserving suspended cells, but they do not demonstrate sufficient efficacy for two-dimensional (2D)-cultured cells. In the past decade, small molecules and polymers have been studied as cryoprotectants. Some L-amino acids have been reported to be natural and biocompatible cryoprotectants. However, the cryoprotective effects of D-amino acids have not been investigated for such organized cells. In the present study, the cryoprotective effects of D- and L-amino acids and previously reported cryoprotectants were assessed using HepG2 cells cultured on a microplate without suspending the cells. d-Proline had the highest cryoprotective effect on 2D-cultured cells. The composition of the cell-freezing solution and freezing conditions were then optimized. The d-proline-containing cell-freezing solution also effectively worked for other cell lines. To minimize the amount of animal-derived components, fetal bovine serum in the cell freezing solution was substituted with bovine serum albumin and StemFit (a commercial supplement for stem cell induction). Further investigations on the mechanism of cryopreservation suggested that d-proline protected enzymes essential for cell survival from freeze-induced damage. In conclusion, an effective and xeno-free cell-freezing solution was produced using d-proline combined with dimethyl sulfoxide and StemFit for 2D-cultured cells.