Neuroblastoma, a type of cancer that is common in children, is composed of two genetically clonal but epigenetically distinct cell types: mesenchymal (MES) and adrenergic (ADRN) types, controlled by super‐enhancer‐associated lineage‐specific transcription factor networks. Mesenchymal‐type cells are more migratory, resistant to chemotherapy, and prevalent in relapse tumors. Importantly, both cell types spontaneously transdifferentiate into one another, and this interconversion can be induced by genetic manipulations. However, the mechanisms of their spontaneous transdifferentiation and extracellular factors inducing this phenomenon have not yet been elucidated. Using a unique approach involving gene set enrichment analysis, we selected six ADRN and 10 MES candidate factors, possibly inducing ADRN and MES phenotypes, respectively. Treatment with a combination of 10 MES factors clearly induced the MES gene expression profile in ADRN‐type SH‐SY5Y neuroblastoma cells. Considering the effects on gene expression profile, migration ability, and chemoresistance, a combination of tumor necrosis factor alpha (TNF‐α) and epidermal growth factor (EGF) was sufficient to synergistically induce the ADRN‐to‐MES transdifferentiation in SH‐SY5Y cells. In addition, human neuroblastoma cohort analysis revealed that the expression of TNF and EGF receptors was strongly associated with MES gene expression signatures, supporting their important roles in transdifferentiation in vivo. Collectively, we propose a mechanism of neuroblastoma transdifferentiation induced by extracellular growth factors, which can be controlled in clinical situations, providing a new therapeutic possibility.

Background: Combinatorial gene regulation by multiple microRNAs (miRNAs) is widespread and closely spaced target sites often act cooperatively to achieve stronger repression (“neighborhood” miRNA cotargeting). While miRNA cotarget sites are suggested to be more conserved and implicated in developmental control, the pathological significance of miRNA cotargeting remains elusive.Results: Here, we report the pathogenic impacts of combinatorial miRNA regulation on inflammation in systemic lupus erythematosus (SLE). In the SLE mouse model, we identified the downregulation of two miRNAs, miR-128 and miR-148a, by TLR7 stimulation in plasmacytoid dendritic cells. Functional analyses using human cell lines demonstrated that miR-128 and miR-148a additively target KLF4 via extensively overlapping target sites (“seed overlap” miRNA cotargeting) and suppress the inflammatory responses. At the transcriptome level, “seed overlap” miRNA cotargeting increases susceptibility to downregulation by two miRNAs, consistent with additive but not cooperative recruitment of two miRNAs. Systematic characterization further revealed that extensive “seed overlap” is a prevalent feature among broadly conserved miRNAs. Highly conserved target sites of broadly conserved miRNAs are largely divided into two classes—those conserved among eutherian mammals and from human toCoelacanth, and the latter, including KLF4-cotargeting sites, has a stronger association with both “seed overlap” and “neighborhood” miRNA cotargeting. Furthermore, a deeply conserved miRNA target class has a higher probability of haplo-insufficient genes.Conclusions: Our study collectively suggests the complexity of distinct modes of miRNA cotargeting and the importance of their perturbations in human diseases.

Monocarboxylates, such as lactate and pyruvate, are precursors for biosynthetic pathways, including those for glucose, lipids, and amino acids via the tricarboxylic acid (TCA) cycle and adjacent metabolic networks. The transportation of monocarboxylates across the cellular membrane is performed primarily by monocarboxylate transporters (MCTs), the membrane localization and stabilization of which are facilitated by the transmembrane protein basigin (BSG). Here, we demonstrate that the MCT/BSG axis sits at a crucial intersection of cellular metabolism. Abolishment of MCT1 in the plasma membrane was achieved by Bsg depletion, which led to gluconeogenesis impairment via preventing the influx of lactate and pyruvate into the cell, consequently suppressing the TCA cycle. This net anaplerosis suppression was compensated in part by the increased utilization of glycogenic amino acids (e.g., alanine and glutamine) into the TCA cycle and by activated ketogenesis through fatty acid β-oxidation. Complementary to these observations, hyperglycemia and hepatic steatosis induced by a high-fat diet were ameliorated in Bsg -deficient mice. Furthermore, Bsg deficiency significantly improved insulin resistance induced by a high-fat diet. Taken together, the plasma membrane–selective modulation of lactate and pyruvate transport through BSG inhibition could potentiate metabolic flexibility to treat metabolic diseases.

Key Points: Systemically administered anti–microRNA (miR)-21-serinol nucleic acid (SNA) accumulates in the kidneys and suppresses renal cyst growth. Anti–miR-21-SNA treatment alters mitochondrial metabolism, apoptotic signaling, and inhibits kidney tissue fibrosis. In human autosomal dominant polycystic kidney disease kidney cells, anti–miR-21-SNA treatment reduces cyst size and intracellular cAMP content and increases Ca2⁺ concentration. Background: Hereditary cystic kidney diseases are ciliopathies characterized by functional defects in the primary cilia of renal tubules. Abnormalities in the primary cilia enhance cell proliferation signals and cause cyst enlargement. The most common type is autosomal dominant polycystic kidney disease (ADPKD), but other diseases, such as nephronophthisis, have been discovered to be more common than previously considered. In ADPKD, several microRNAs are reportedly aberrantly expressed and involved in disease pathogenesis. Among these, we focused on microRNA (miR)-21, which is upregulated in response to cAMP signaling. In this study, we aimed to newly generate an anti–miR-21 oligonucleotide synthesized from serinol nucleic acid (anti–miR-21-SNA) to improve anti-microRNA activity and investigate its effects on cyst growth in vivo and in vitro. Methods: We evaluated the effectiveness of anti–miR-21 treatment using an serinol nucleic acid–based antisense oligonucleotide in a mouse model of cystic kidney disease and human ADPKD cells. Results: Our study revealed that anti–miR-21-SNA effectively prevented cyst growth in vivo and in vitro. In the mouse model of cystic kidney disease, we systemically administered anti–miR-21-SNA and observed its accumulation primarily in the kidneys, suggesting effective drug delivery. Anti–miR-21-SNA treatment reduced kidney size and blood urea nitrogen levels without inducing hepatotoxicity. Mechanistically, molecules related to mitochondrial metabolism, apoptosis, and fibrosis pathways were involved. In vitro, anti–miR-21-SNA treatment of primary cultured kidney cells from an ADPKD patient reduced cyst volume and intracellular cAMP content and increased Ca²⁺ concentration, supporting the efficacy of this treatment. Conclusions: Our results showed that anti–miR-21-SNA treatment represents a potential therapeutic strategy for cystic kidney disease.

MYCN amplification occurs in approximately 20–30% of neuroblastoma patients and correlates with poor prognosis. The TH-MYCN transgenic mouse model mimics the development of human high-risk neuroblastoma and provides strong evidence for the oncogenic function of MYCN. In this study, we identified mitotic dysregulation as a hallmark of tumor initiation in the pre-cancerous ganglia from TH-MYCN mice that persists through tumor progression. Single-cell quantitative-PCR of coeliac ganglia from 10-day-old TH-MYCN mice revealed overexpression of mitotic genes in a subpopulation of premalignant neuroblasts at a level similar to single cells derived from established tumors. Prophylactic treatment using antimitotic agents barasertib and vincristine significantly delayed the onset of tumor formation, reduced pre-malignant neuroblast hyperplasia, and prolonged survival in TH-MYCN mice. Analysis of human neuroblastoma tumor cohorts showed a strong correlation between dysregulated mitosis and features of MYCN amplification, such as MYC(N) transcriptional activity, poor overall survival, and other clinical predictors of aggressive disease. To explore the therapeutic potential of targeting mitotic dysregulation, we showed that genetic and chemical inhibition of mitosis led to selective cell death in neuroblastoma cell lines with MYCN over-expression. Moreover, combination therapy with antimitotic compounds and BCL2 inhibitors exploited mitotic stress induced by antimitotics and was synergistically toxic to neuroblastoma cell lines. These results collectively suggest that mitotic dysregulation is a key component of tumorigenesis in early neuroblasts, which can be inhibited by the combination of antimitotic compounds and pro-apoptotic compounds in MYCN-driven neuroblastoma.