Exclusion of HDAC1/2 complexes by oncogenic nuclear condensates.

Nuclear condensates have been shown to regulate cell fate control, but its role in oncogenic transformation remains largely unknown. Here we show acquisition of oncogenic potential by nuclear condensate remodeling. The proto-oncogene SS18 and its oncogenic fusion SS18-SSX1 can both form condensates, but with drastically different properties and impact on 3D genome architecture. The oncogenic condensates, not wild type ones, readily exclude HDAC1 and 2 complexes, thus, allowing aberrant accumulation of H3K27ac on chromatin loci, leading to oncogenic expression of key target genes. These results provide the first case for condensate remodeling as a transforming event to generate oncogene and such condensates can be targeted for therapy. One sentence summary: Expulsion of HDACs complexes leads to oncogenic transformation.

Mechanical strain treatment improves nuclear transfer reprogramming efficiency by enhancing chromatin accessibility.

Cellular mechanical properties are considered to be important factors affecting cell fate transitions, but the links between cellular mechanical properties and transition efficiency and chromatin structure remain elusive. Here, we predicted that mechanical strain treatment could induce signatures of cellular dedifferentiation and transdifferentiation, and we validated this prediction by showing that mechanical strain-treated mouse cumulus cells (CCs) exhibit significantly improved somatic cell nuclear transfer (SCNT) reprogramming efficiency. We found that the chromatin accessibility of CCs was globally increased by mechanical strain treatment and that this increase was partially mediated by the induction of the YAP-TEAD interaction. Moreover, using mechanical strain-treated CCs could prevent transcriptional dysregulation in SCNT embryos. Taken together, our study results demonstrated that modulating cell mechanical properties to regulate epigenetic status is a promising approach to facilitate cell fate transition.

UdgX-Mediated Uracil Sequencing at Single-Nucleotide Resolution.

As an aberrant base in DNA, uracil is generated by either deoxyuridine (dU) misincorporation or cytosine deamination, and involved in multiple physiological and pathological processes. Genome-wide profiles of uracil are important for study of these processes. Current methods for whole-genome mapping of uracil all rely on uracil-DNA N-glycosylase (UNG) and are limited in resolution, specificity, and/or sensitivity. Here, we developed a UdgX cross-linking and polymerase stalling sequencing ("Ucaps-seq") method to detect dU at single-nucleotide resolution. First, the specificity of Ucaps-seq was confirmed on synthetic DNA. Then the effectiveness of the approach was verified on two genomes from different sources. Ucaps-seq not only identified the enrichment of dU at dT sites in pemetrexed-treated cancer cells with globally elevated uracil but also detected dU at dC sites within the "WRC" motif in activated B cells which have increased dU in specific regions. Finally, Ucaps-seq was utilized to detect dU introduced by the cytosine base editor (nCas9-APOBEC) and identified a novel off-target site in cellular context. In conclusion, Ucaps-seq is a powerful tool with many potential applications, especially in evaluation of base editing fidelity.

Single-cell transcriptomics of LepR-positive skeletal cells reveals heterogeneous stress-dependent stem and progenitor pools.

Leptin receptor (LepR)-positive cells are key components of the bone marrow hematopoietic microenvironment, and highly enrich skeletal stem and progenitor cells that maintain homeostasis of the adult skeleton. However, the heterogeneity and lineage hierarchy within this population has been elusive. Using genetic lineage tracing and single-cell RNA sequencing, we found that Lepr-Cre labels most bone marrow stromal cells and osteogenic lineage cells in adult long bones. Integrated analysis of Lepr-Cre-traced cells under homeostatic and stress conditions revealed dynamic changes of the adipogenic, osteogenic, and periosteal lineages. Importantly, we discovered a Notch3+ bone marrow sub-population that is slow-cycling and closely associated with the vasculatures, as well as key transcriptional networks promoting osteo-chondrogenic differentiation. We also identified a Sca-1+ periosteal sub-population with high clonogenic activity but limited osteo-chondrogenic potential. Together, we mapped the transcriptomic landscape of adult LepR+ stem and progenitor cells and uncovered cellular and molecular mechanisms underlying their maintenance and lineage specification.

Cerebral infarction as the first symptom in acute promyelocytic leukemia: A case report and literature review. / ä»¥è„‘æ¢—æ­»ä¸ºé¦–å‘ç—‡çŠ¶çš„æ€¥æ€§æ—©å¹¼ç²’ç»†èƒžç™½è¡€ç— 1例及文献回顾.

In the clinical settings, disseminated intravascular coagulation (DIC) and complications such as hemorrhage are commonly seen in acute promyelocytic leukemia patients, whereas thrombosis is rarely reported. We reported a case here that the patient presented with cerebral infarction as the first manifestation. During the admission, the patient encountered differentiation syndrome, pulmonary embolism, pulmonary hemorrhage, and myocardial ischemia, as well as bleeding and thrombosis complications. Hence the patient was diagnosed as DIC. After the treatment of blood transfusion instead of anticoagulation, his condition was stable and the remission was completely achieved. The treatment experience provides guides for other patients with similar complications of simultaneous bleeding and thrombosis.

Interdigitating dendritic cell sarcoma of the spleen with hepatic failure after chemotherapy: A case report.

RATIONALE: Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare disease originating from dendritic cells (DCs). There are few cases report interdigitating dendritic cell sarcoma of spleen along with their pathological characteristics and treatment. PATIENT CONCERNS: Here we report a case of IDCS in 53-year-old female who presented spleen enlargement and thrombocytopenia. DIAGNOSES: The patient underwent surgical resection of spleen, and the pathology confirmed IDCS. INTERVENTIONS: She received surgical resection of spleen and one cycle of chemotherapy (ABVD with ifosfamide and oxaliplatin) after surgery. OUTCOMES: She died of severe hepatic failure caused by chemotherapy. DISCUSSION: IDCS is a rare disease with insufficient treatment guidelines. We adopted chemotherapy of ABVD with ifosfamide and oxaliplatin which showed no improvement but led to life-threatening liver damage.