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Key Points Forty-five genes that encode kinesin superfamily proteins (also known as KIFs) have been discovered in the mouse and human genomes. KIFs are molecular motors that directionally transport various cargos, including membranous organelles, protein complexes and mRNAs, along the microtubule system. The mechanisms by which different kinesins recognize, bind and unload specific cargo have been identified. The spatiotemporal delivery of cargos by KIF-based transport can be regulated by phosphorylation, G proteins and Ca 2+ levels. It is now recognized that kinesins have unexpected roles in the regulation of physiological processes, such as higher brain function, tumour suppression and developmental patterning. Kinesins are molecular motors that directionally transport various cargos, including membranous organelles, protein complexes and mRNAs. The mechanisms by which kinesins recognize, bind and unload cargo, and also regulate processes such as higher brain function, tumour suppression and developmental patterning, are becoming clear. Intracellular transport is fundamental for cellular function, survival and morphogenesis. Kinesin superfamily proteins (also known as KIFs) are important molecular motors that directionally transport various cargos, including membranous organelles, protein complexes and mRNAs. The mechanisms by which different kinesins recognize and bind to specific cargos, as well as how kinesins unload cargo and determine the direction of transport, have now been identified. Furthermore, recent molecular genetic experiments have uncovered important and unexpected roles for kinesins in the regulation of such physiological processes as higher brain function, tumour suppression and developmental patterning. These findings open exciting new areas of kinesin research.

Somatic mutations of ASXL1 are frequently detected in age-related clonal hematopoiesis (CH). However, how ASXL1 mutations drive CH remains elusive. Using knockin (KI) mice expressing a C-terminally truncated form of ASXL1-mutant (ASXL1-MT), we examined the influence of ASXL1-MT on physiological aging in hematopoietic stem cells (HSCs). HSCs expressing ASXL1-MT display competitive disadvantage after transplantation. Nevertheless, in genetic mosaic mouse model, they acquire clonal advantage during aging, recapitulating CH in humans. Mechanistically, ASXL1-MT cooperates with BAP1 to deubiquitinate and activate AKT. Overactive Akt/mTOR signaling induced by ASXL1-MT results in aberrant proliferation and dysfunction of HSCs associated with age-related accumulation of DNA damage. Treatment with an mTOR inhibitor rapamycin ameliorates aberrant expansion of the HSC compartment as well as dysregulated hematopoiesis in aged ASXL1-MT KI mice. Our findings suggest that ASXL1-MT provokes dysfunction of HSCs, whereas it confers clonal advantage on HSCs over time, leading to the development of CH. ASXL1 mutations are frequently found in age-related clonal haemaotopoiesis (CH), but how they drive CH is unclear. Here the authors show that expression of C-terminal truncated ASXL1 in haematopoietic stem cells (HSCs) leads to Akt de-ubiquitination, activated Akt/mTOR signaling, and aberrant HSC proliferation.

Uterine adenomyosis is a benign disorder that often co-occurs with endometriosis and/or leiomyoma, and impairs quality of life. The genomic features of adenomyosis are unknown. Here we apply next-generation sequencing to adenomyosis (70 individuals and 192 multi-regional samples), as well as co-occurring leiomyoma and endometriosis, and find recurring KRAS mutations in 26/70 (37.1%) of adenomyosis cases. Multi-regional sequencing reveals oligoclonality in adenomyosis, with some mutations also detected in normal endometrium and/or co-occurring endometriosis. KRAS mutations are more frequent in cases of adenomyosis with co-occurring endometriosis, low progesterone receptor (PR) expression, or progestin (dienogest; DNG) pretreatment. DNG’s anti-proliferative effect is diminished via epigenetic silencing of PR in immortalized cells with mutant KRAS . Our genomic analyses suggest that adenomyotic lesions frequently contain KRAS mutations that may reduce DNG efficacy, and that adenomyosis and endometriosis may share molecular etiology, explaining their co-occurrence. These findings could lead to genetically guided therapy and/or relapse risk assessment after uterine-sparing surgery. Uterine adenomyosis often co-occurs with endometriosis or leiomyoma, but little is known about its molecular underpinnings. Here, the authors show that KRAS mutations are frequent in this disease, which might reduce sensitivity to progestin treatment via epigenetic silencing of the progesterone receptor.

Odontogenic myxoma (OM) and odontogenic myxofibroma (OMF) are rare benign odontogenic tumors characterized by heterogeneous stromal composition, for which objective and reproducible pathological evaluation remains challenging. This multicenter study aimed to quantitatively assess fibrous tissue proportion (FTP) using AI-assisted digital pathology and to explore its clinicopathological relevance across odontogenic myxoma spectrum lesions. A total of 143 surgical specimens were collected from 34 institutions, and 100 cases were included after centralized pathological review. FTP was independently estimated by two board-certified oral pathologists to generate expert reference data. Whole-slide images of Masson’s trichrome–stained sections were analyzed using a multi-stage deep learning pipeline implemented within a unified digital pathology platform. Agreement between expert assessment and quantitative measurements was evaluated, and associations between FTP and clinical variables were explored. Quantitative FTP measurements showed good agreement with expert pathological evaluation and revealed substantial inter-institutional variability in pathological diagnoses. In clinicopathological analyses, higher FTP was independently associated with unilocular radiological morphology. These findings demonstrate that AI-assisted quantitative pathology provides a reproducible framework for visualizing stromal heterogeneity in odontogenic myxoma spectrum lesions and may support more consistent clinicopathological interpretation across institutions.

Clonal hematopoiesis of indeterminate potential (CHIP) is an age‐associated phenomenon characterized by clonal expansion of blood cells harboring somatic mutations in hematopoietic genes, including DNMT3A, TET2, and ASXL1. Clinical evidence suggests that CHIP is highly prevalent and associated with poor prognosis in solid‐tumor patients. However, whether blood cells with CHIP mutations play a causal role in promoting the development of solid tumors remained unclear. Using conditional knock‐in mice that express CHIP‐associated mutant Asxl1 (Asxl1‐MT), we showed that expression of Asxl1‐MT in T cells, but not in myeloid cells, promoted solid‐tumor progression in syngeneic transplantation models. We also demonstrated that Asxl1‐MT–expressing blood cells accelerated the development of spontaneous mammary tumors induced by MMTV‐PyMT. Intratumor analysis of the mammary tumors revealed the reduced T‐cell infiltration at tumor sites and programmed death receptor‐1 (PD‐1) upregulation in CD8+ T cells in MMTV‐PyMT/Asxl1‐MT mice. In addition, we found that Asxl1‐MT induced T‐cell dysregulation, including aberrant intrathymic T‐cell development, decreased CD4/CD8 ratio, and naïve‐memory imbalance in peripheral T cells. These results indicate that Asxl1‐MT perturbs T‐cell development and function, which contributes to creating a protumor microenvironment for solid tumors. Thus, our findings raise the possibility that ASXL1‐mutated blood cells exacerbate solid‐tumor progression in ASXL1‐CHIP carriers. ASXL1 mutations found in CHIP carriers alter T‐cell development and function, which contributes to creating a protumor environment for solid tumors.

An early stage in mouse blood development is reconstructed from gene expression data on thousands of single cells. Reconstruction of the molecular pathways controlling organ development has been hampered by a lack of methods to resolve embryonic progenitor cells. Here we describe a strategy to address this problem that combines gene expression profiling of large numbers of single cells with data analysis based on diffusion maps for dimensionality reduction and network synthesis from state transition graphs. Applying the approach to hematopoietic development in the mouse embryo, we map the progression of mesoderm toward blood using single-cell gene expression analysis of 3,934 cells with blood-forming potential captured at four time points between E7.0 and E8.5. Transitions between individual cellular states are then used as input to develop a single-cell network synthesis toolkit to generate a computationally executable transcriptional regulatory network model of blood development. Several model predictions concerning the roles of Sox and Hox factors are validated experimentally. Our results demonstrate that single-cell analysis of a developing organ coupled with computational approaches can reveal the transcriptional programs that underpin organogenesis.

Mice with the C3H background show greater behavioral propensity for schizophrenia, including lower prepulse inhibition (PPI), than C57BL/6 (B6) mice. To characterize as‐yet‐unknown pathophysiologies of schizophrenia, we undertook proteomics analysis of the brain in these strains, and detected elevated levels of Mpst, a hydrogen sulfide (H 2 S)/polysulfide‐producing enzyme, and greater sulfide deposition in C3H than B6 mice. Mpst ‐deficient mice exhibited improved PPI with reduced storage sulfide levels, while Mpst ‐transgenic (Tg) mice showed deteriorated PPI, suggesting that “sulfide stress” may be linked to PPI impairment. Analysis of human samples demonstrated that the H 2 S/polysulfides production system is upregulated in schizophrenia. Mechanistically, the Mpst‐ Tg brain revealed dampened energy metabolism, while maternal immune activation model mice showed upregulation of genes for H 2 S/polysulfides production along with typical antioxidative genes, partly via epigenetic modifications. These results suggest that inflammatory/oxidative insults in early brain development result in upregulated H 2 S/polysulfides production as an antioxidative response, which in turn cause deficits in bioenergetic processes. Collectively, this study presents a novel aspect of the neurodevelopmental theory for schizophrenia, unraveling a role of excess H 2 S/polysulfides production. Synopsis This study proposes a novel concept that excess hydrogen sulfide production (sulfide stress) underlies a schizophrenia pathophysiology in the realm of neurodevelopmental hypothesis of the disease. Targeting the metabolic pathway of hydrogen sulfide provides a novel therapeutic approach. Mpst‐deficient mice exhibited improved prepulse inhibition (PPI), a typical schizophrenia‐relevant endophenotype, with reduced sulfide levels, while Mpst‐transgenic mice showed deteriorated PPI. Postmortem brains and iPS‐derived cells from a subset of schizophrenia patients displayed evidence for sulfide stress. Sulfide stress condition stemmed from insults in developing brain in mouse models and elicited dampened energy metabolism. MPST expression level in hair follicles has a potential to stratify schizophrenia patients with sulfide stress. Graphical Abstract This study proposes a novel concept that excess hydrogen sulfide production (sulfide stress) underlies a schizophrenia pathophysiology in the realm of neurodevelopmental hypothesis of the disease. Targeting the metabolic pathway of hydrogen sulfide provides a novel therapeutic approach.

Leukemia stem cells (LSCs) in chronic myeloid leukemia (CML) are quiescent, insensitive to BCR-ABL1 tyrosine kinase inhibitors (TKIs) and responsible for CML relapse. Therefore, eradicating quiescent CML LSCs is a major goal in CML therapy. Here, using a G 0 marker (G 0 M), we narrow down CML LSCs as G 0 M- and CD27- double positive cells among the conventional CML LSCs. Whole transcriptome analysis reveals NF-κB activation via inflammatory signals in imatinib-insensitive quiescent CML LSCs. Blocking NF-κB signals by inhibitors of interleukin-1 receptor-associated kinase 1/4 (IRAK1/4 inhibitors) together with imatinib eliminates mouse and human CML LSCs. Intriguingly, IRAK1/4 inhibitors attenuate PD-L1 expression on CML LSCs, and blocking PD-L1 together with imatinib also effectively eliminates CML LSCs in the presence of T cell immunity. Thus, IRAK1/4 inhibitors can eliminate CML LSCs through inhibiting NF-κB activity and reducing PD-L1 expression. Collectively, the combination of TKIs and IRAK1/4 inhibitors is an attractive strategy to achieve a radical cure of CML. Leukemic stem cells (LSCs) in chronic myeloid leukemia are resistant to imatinib and therefore are a cause of relapse. The authors show that IRAK1/4-NF-κB-PD-L1 signaling is critical to mediate imatinib resistance in LSCs and that combining imatinib with blocking this signalling pathway can eliminate LSCs.

The precise specification of left–right asymmetry is an essential process for patterning internal organs in vertebrates. In mouse embryonic development, the symmetry-breaking process in left–right determination is initiated by a leftward extraembryonic fluid flow on the surface of the ventral node. However, it is not known whether the signal transduction mechanism of this flow is chemical or mechanical. Here we show that fibroblast growth factor (FGF) signalling triggers secretion of membrane-sheathed objects 0.3–5 µm in diameter termed ‘nodal vesicular parcels’ (NVPs) that carry Sonic hedgehog and retinoic acid. These NVPs are transported leftward by the fluid flow and eventually fragment close to the left wall of the ventral node. The silencing effects of the FGF-receptor inhibitor SU5402 on NVP secretion and on a downstream rise in Ca 2+ were sufficiently reversed by exogenous Sonic hedgehog peptide or retinoic acid, suggesting that FGF-triggered surface accumulation of cargo morphogens may be essential for launching NVPs. Thus, we propose that NVP flow is a new mode of extracellular transport that forms a left–right gradient of morphogens. No left or right turn Though symmetrical from the outside, the body plan of vertebrates and other animals is far from symmetrical inside. By the time the human heart and lung develop in the embryo they are directed to the left and right of the body cavity. Much research has gone into establishing the genetics and signalling mechanisms that impose this asymmetry. But there is a catch: some tissues, chiefly the muscles and skeleton, must ignore or overrule the instruction if they are not to become asymmetric. Three papers in this issue, and a News and Views piece by Eran Hornstein and Clifford J. Tabin, address the fascinating question of how the somites, embryonic elements that give rise to symmetrical tissues, pull off that trick.

ASXL1 mutations occur frequently in myeloid neoplasms and are associated with poor prognosis. However, the mechanisms by which mutant ASXL1 induces leukaemogenesis remain unclear. In this study, we report mutually reinforcing effects between a C-terminally truncated form of mutant ASXL1 (ASXL1-MT) and BAP1 in promoting myeloid leukaemogenesis. BAP1 expression results in increased monoubiquitination of ASXL1-MT, which in turn increases the catalytic function of BAP1. This hyperactive ASXL1-MT/BAP1 complex promotes aberrant myeloid differentiation of haematopoietic progenitor cells and accelerates RUNX1-ETO-driven leukaemogenesis. Mechanistically, this complex induces upregulation of posterior HOXA genes and IRF8 through removal of H2AK119 ubiquitination. Importantly, BAP1 depletion inhibits posterior HOXA gene expression and leukaemogenicity of ASXL1-MT-expressing myeloid leukemia cells. Furthermore, BAP1 is also required for the growth of MLL-fusion leukemia cells with posterior HOXA gene dysregulation. These data indicate that BAP1, which has long been considered a tumor suppressor, in fact plays tumor-promoting roles in myeloid neoplasms. ASXL1 gene is often mutated in myeloid malignancies. Here, the authors show that mutant ASXL1 and BAP1 are in a positive feedback loop such that BAP1 induces monoubiquitination of mutant ASXL1, which in turn enhances BAP1 activity to potentiate myeloid transformation via HOXA clusters and IRF8.