Genes to Cells最新文献

Neuroblastoma (NB) is a pediatric solid tumor originating from neural crest cells (NCCs), which are precursors of the sympathetic nervous system. MYCN amplification is a key factor contributing to the poor prognosis of NB. Anaplastic lymphoma kinase (ALK) alterations, including mutations and amplification, activate oncogenic signaling pathways that, together with MYCN amplification, further enhance tumor malignancy. NCCs are mainly classified into cranial NCCs (cNCCs) and trunk NCCs (tNCCs). Recent studies have reported NB development from tNCCs. However, the potential for NB development from cNCCs remains unexplored. In this study, we sought to mimic the tumorigenic process of NB by overexpressing MYCN and ALK in cNCCs derived from human induced pluripotent stem cells. These modified cells, when subcutaneously transplanted into immunodeficient mice, induced NB-like tumors and could thus be used as an in vitro model to study this tumor. Through extensive gene expression profiling and whole-exome sequencing of MYCN/ALK-induced clones, we identified key features of NB, including loss of NF1 and gain of 17q chromosome, which are critical for the development of malignant tumor. This model provides a valuable platform for studying the biological mechanisms driving ALK and MYCN amplification in NB derived from cNCCs.

Various molecular mechanisms in mature adipose tissue regulate whole-body physiology. In contrast, our current understanding of the development of this tissue is limited. The adult fat body (AFB) of Drosophila melanogaster is an emerging model for investigating the regulatory mechanisms of adipose tissue morphogenesis in vivo. AFB precursor cells undergo long-range directional and collective migration, proliferation, and homotypic adhesion, leading to the formation of monolayered AFB during metamorphosis. Here, we show that a Drosophila ADAM10 transmembrane metalloprotease, Kuzbanian (Kuz), is required for AFB morphogenesis in the precursor cells at the onset of adhesion. Histological and ultrastructural analyses revealed that the kuz knocked-down AFB cells formed multilayered structures or clumps, indicating that Kuz is essential for forming a single-cell-thick tissue sheet. Furthermore, adults with the morphologically altered AFB were supersensitive to starvation stress. Finally, we tested the hypothesis that Notch (N), a well-characterized substrate for Kuz or ADAM10, participates in AFB development, and found that knocking down N reduced AFB area coverage and made the adults less adaptive to starvation, similar to kuz knockdown. Altogether, our study highlights the critical role of Kuz in both the architecture and function of adult adipose tissue.

In epithelia, the desmosome is a cell–cell adhesive junction that anchors keratin filaments, thereby providing tissue integrity and mechanical resistance. Compared with considerable study on the desmosome in stratified epithelia, the mechanism of desmosome assembly and its functional roles remain incompletely understood in single-layered (simple) epithelia. Here we show that not only E-cadherin (E-cad) but also cadherin-6 (Cdh6) participates in recruitment of plakoglobin (Pg) from E-cad-containing cytoplasmic vesicles to cell–cell junctional regions during Ca²⁺-induced desmosome formation in simple epithelial MDCK cells. Subsequently, Pg cooperates with its related proteins plakophilin-2 (PKP2) and plakophilin-3 (PKP3), being recruited independently of E-cad/Cdh6, in junctional localization of the desmosomal cadherins desmoglein-2 (Dsg2) and desmocollin-2 (Dsc2) and the keratin-anchoring protein desmoplakin (DP), leading to functional keratin filament network formation. We also demonstrate that DP contributes to establishment of apical-basal cell polarity during cystogenesis in 3D culture of MDCK cells; depletion of DP results in formation of aberrant cysts containing cells with inverted polarity. Furthermore, the morphology of the nucleus in MDCK cells appears to be regulated by proper desmosome assembly and subsequent keratin network formation, because depletion of DP as well as that of E-cad/Cdh6, Pg, or PKP2/3 results in an irregular nuclear shape.

Heme synthesis has been considered essential, yet cancer cells paradoxically maintain high proliferation despite suppressing the pathway, with low expression of δ-aminolevulinate dehydratase (ALAD), the second enzyme of the pathway, which correlates with a poor prognosis. We propose that this suppression is a novel survival strategy to avoid toxic intermediates. Supporting this, we observed that cancer cells vigorously grow after the complete knockout of the essential ALAD gene, demonstrating the pathway's non-essentiality in malignancy. This ALAD suppression offers a dual advantage: evading growth suppression and promoting malignant phenotypes (epithelial–mesenchymal transition). Crucially, the toxicity induced by reactivating the pathway is not dependent on conventional porphyrin (PpIX) or reactive oxygen species, but rather on an unknown intermediate metabolite upstream of PpIX. Activating the heme pathway, for example, by administration of its starting substrate 5-aminolevulinic acid, provides the impetus for a new therapeutic approach to break this defense.

Var2CSA, a member of the Plasmodium falciparum erythrocyte membrane protein (PfEMP) family, specifically binds to various human cancer cells through oncofetal chondroitin sulfate (ofCS) expressed on cell surfaces. This unique binding property has raised considerable expectations for the application of var2CSA in cancer-targeted diagnostics and therapies. Baculovirus vectors, known for their safety compared with other viral vectors, possess the ability to introduce genes into human cancer cells. We previously constructed a baculovirus expressing var2CSA containing DBL1X-DBL3X domains (var2CSA-type baculovirus) and demonstrated enhanced gene transduction efficiency in cancer cells. In the present study, we sought to further improve gene delivery by generating two truncated var2CSA constructs: rVAR2 (DBL1X-ID2a) and ID1-DBL2Xb. The rVAR2 was successfully expressed in purified budded virions, whereas the ID1-DBL2Xb showed no detectable expression in budded virions due to very low protein levels in insect Sf9 cells. Functional evaluation in HepG2 hepatocellular carcinoma cells revealed that rVAR2-type baculovirus exhibited significantly higher gene delivery efficiency than the var2CSA-type baculovirus. These findings suggest that rVAR2-expressing baculovirus represents a promising tool for cancer gene therapy, where enhanced gene delivery efficiency is highly desirable.

Long noncoding RNAs (lncRNAs) are abundantly transcribed in eukaryotes, but most of their physiological roles, especially in neural development, remain unclear due to limited in vivo studies. Here we show that Lobe-less (LOL) lncRNA of Drosophila is expressed in developing neuronal cells and is required for the development of the mushroom body, a center of memory and learning in the insect brain. lol mutant flies exhibit defective morphology of the mushroom body and axon branch patterns, as well as misregulation of neurogenic genes. LOL RNA forms nuclear puncta and genetically interacts with Polycomb group genes in the regulation of homeotic genes. These findings demonstrate that this long ncRNA plays a critical role in the epigenetic control of neural circuit formation.

The 7th International Conference on Plant Vascular Biology 2025 (PVB2025) took place at the KKR Hotel Osaka from July 7th to July 12th. The conference attracted 169 participants from 20 countries, including 105 attendees from outside Japan. PVB2025 featured 12 plenary scientific sessions, 23 invited talks, 31 contributed talks selected from submitted abstracts, and 89 poster presentations. Plant vascular biology is a crucial area of plant science, as vascular systems transport essential resources that plants need for survival. These systems also function as a communication network, facilitating internal and external information flow at the whole-body level. Participants at PVB2025 aimed to share their latest findings in this field. Additionally, the conference emphasized the importance of inspiring and encouraging young scientists who will become the next generation of community leaders. To support this initiative, we offered five travel awards and five Best Poster Awards to undergraduate students, graduate students, and early-career professionals. Overall, PVB2025 successfully fostered discussions and collaborations in plant vascular biology research while allowing participants to experience the unique and vibrant culture of Osaka through “eating and talking till you drop.”

Hepatic peroxisome proliferator-activated receptor gamma (PPARγ) promotes fat accumulation in the liver of leptin-deficient (ob/ob) mice. However, the mechanism underlying PPARγ-dependent fat accumulation remains unclear. In this study, we identified miR-205-5p as a liver-enriched microRNA regulated by PPARγ. miR-205-5p was significantly upregulated in the ob/ob mouse livers and induced by treatment with the PPARγ-specific agonist rosiglitazone. In contrast, its expression was markedly reduced in liver-specific PPARγ knockout mice. In both nonalcoholic fatty liver and nonalcoholic steatohepatitis models, hepatic miR-205-5p levels were elevated, whereas serum levels were decreased. In HepG2 cells treated with a mixture of oleic and palmitic acids to induce fat accumulation, overexpression of miR-205-5p increased the expression of lipogenic gene (ACC) and decreased the expression of the rate-limiting enzyme for fatty acid β-oxidation (ACOX1) and transcription factors involved in fatty acid oxidation and oxidative stress (HNF4A and NRF2). Furthermore, forced expression of miR-205-5p significantly increased fat levels in HepG2 cells. These findings suggest that the PPARγ-miR-205-5p axis plays a key role in the promotion of hepatic fat accumulation. Collectively, our data indicate that miR-205-5p has potential as a downstream effector of hepatic PPARγ signaling and may serve as a biomarker and therapeutic target for nonalcoholic fatty liver disease.

Thymic T cell development shows homeostasis against various stressors. Invariant natural killer T (iNKT) cells in the thymus contribute to recovery of thymic development after irradiation owing to their initial tolerance to irradiation compared to conventional thymocytes. However, whether and how iNKT cell development recovers from irradiation remains unknown. Here we show that iNKT cells in the thymus exhibit much slower postirradiation recovery than conventional thymocytes. We observed that fluctuation of V and J genes usage does not correlate with the decrease of iNKT cell population and that irradiation markedly elevated the frequency of cell death relative to proliferation in iNKT cells. Mathematical modeling of recovery dynamics of iNKT cell progenitors implied that lack of rapid proliferation immediately after irradiation, unlike conventional thymocytes, contributes to the prolonged reduction of iNKT cell population. These findings indicate that the development of iNKT cells is subject to long-term effects of irradiation which leads to an increased rate of cell death and raise the possibility of an association between the prolonged reduction of iNKT cells after irradiation and autoimmune diseases caused by irradiation in bone marrow transplantation.