Summary Intracellular pathogens manipulate host organelles to support replication within cells. For Legionella pneumophila, the bacterium translocates proteins that establish an endoplasmic reticulum (ER)-associated replication compartment. We show here that the bacterial Sde proteins target host reticulon 4 (Rtn4) to control tubular ER dynamics, resulting in tubule rearrangements as well as alterations in Rtn4 associated with the replication compartment. These rearrangements are triggered via Sde-promoted ubiquitin transfer to Rtn4, occurring almost immediately after bacterial uptake. Ubiquitin transfer requires two sequential enzymatic activities from a single Sde polypeptide: an ADP-ribosyltransferase and a nucleotidase/phosphohydrolase. The ADP-ribosylated moiety of ubiquitin is a substrate for the nucleotidase/phosphohydrolase, resulting in either transfer of ubiquitin to Rtn4, or phosphoribosylation of ubiquitin in the absence of a ubiquitination target. Therefore, a single bacterial protein drives a multistep biochemical pathway to control ubiquitination and tubular ER function independently of the host ubiquitin machinery.

BackgroundCircular RNAs (circRNAs) have recently been shown to play important roles in different tumors. However, their detailed roles and regulatory mechanisms in pancreatic ductal adenocarcinoma (PDAC) are not well understood. This study aimed to identify enriched circRNAs and detect their functions and mechanisms in PDAC cells and tissues.MethodscircRNA-ASH2L (circ-ASH2L) was identified by circRNA microarray studies based on previous studies, and further detected in PDAC cells and samples by qRT-PCR. The functions of circ-ASH2L were identified by transwell, EdU, cell cycle or Tube formation assays. The regulatory mechanisms of circ-ASH2L were explored by WB, RIP, FISH, dual-luciferase assays, RNA pulldown or other assays.ResultsWe identified a circRNA (circ-ASH2L) based on our previous studies, detected its expression in different malignant cells and found that circ-ASH2L was highly expressed in pancreatic cells or tumor tissues and correlated with tumor malignancy. Further studies revealed that circ-ASH2L promoted tumor invasion, proliferation and angiogenesis by regulating miR-34a, thus regulate Notch 1 expression. Circ-ASH2L served as a miRNA sponge for miR-34a and promoted tumor progression in vivo. Finally, we analyzed circ-ASH2L expression in clinical tissues and found that high circ-ASH2L expression was correlated with lymphatic invasion and TNM stage and was an independent risk factor for pancreatic patient survival.Conclusionscirc-ASH2L play an important role in tumor invasion, and high circ-ASH2L may be a useful marker of PDAC diagnosis or progression.

Achievement of immunocompetent and therapeutic T lymphopoiesis from pluripotent stem cells (PSCs) is a central aim in T cell regenerative medicine. To date, preferentially reconstituting T lymphopoiesis in vivo from PSCs remains a practical challenge. Here we documented that synergistic and transient expression of Runx1 and Hoxa9 restricted in the time window of endothelial-tohematopoietic transition and hematopoietic maturation stages in a PSC differentiation scheme (iR9-PSC) in vitro induced preferential generation of engraftable hematopoietic progenitors capable of homing to thymus and developing into mature T cells in primary and secondary immunodeficient recipients. Single-cell transcriptome and functional analyses illustrated the cellular trajectory of T lineage induction from PSCs, unveiling the T-lineage specification determined at as early as hemogenic endothelial cell stage and identifying the bona fide pre-thymic progenitors. The induced T cells distributed normally in central and peripheral lymphoid organs and exhibited abundant TCRαβ repertoire. The regenerative T lymphopoiesis restored immune surveillance in immunodeficient mice. Furthermore, gene-edited iR9-PSCs produced tumor-specific T cells in vivo that effectively eradicated tumor cells. This study provides insight into universal generation of functional and therapeutic T cells from the unlimited and editable PSC source.

Self-healing mechanism of microcracks on waterborne polyurethane (WPU) with varied disulfide bond contents was investigated thoroughly in this paper. The self-healing process could be observed by an optical microscope, which was divided into two steps. The first step was the cohesive healing movement, closely related with microphase separations and further characterized by the Fourier transform infrared peak fitting, differential scanning calorimetry, and dynamic mechanical thermal analysis. The second step of the exchange reactions of disulfide bonds could be confirmed by the in situ Raman and tensile mechanics. In addition, the cohesive healing behavior was quantitatively described by the kinetic method, and the exchange reaction active energies of disulfide bonds were also calculated to be 20.42 kJ/mol by gel permeation chromatography tests. The best self-healing performance of SHWPUs was WPU-8, and it could be healed at 75 °C in 15 min with 100% self-healing efficiency. Combining the self-healing process observation with the kinetic analysis can provide deep insights into the self-healing mechanism of microcracks.

Deletion of B cell master regulators reprogrammed B cells into T cells that were either functional defects or tumorigenic potential. Here we show that Hoxb5, which is expressed in uncommitted hematopoietic progenitors but absent in committed B and T lineages, could reprogram pro-pre-B cells into functional early T cell progenitors. The reprogramming started in bone marrow and completed in thymus, giving rise to T lymphocytes with transcriptomes, hierarchical differentiation, tissue distribution and immune functions closely resembling their natural counterparts. Hoxb5 repressed B cell master genes, activated T cell regulators and regulated crucial chromatin modifiers in pro-pre-B cells, ultimately driving B to T cell fate conversion. Our results provide a de novo paradigm for generating normal and functional T cells through reprogramming in vivo.

Colorectal cancer (CRC) is the third most commonly diagnosed cancer, which despite recent advances in treatment, remains incurable due to molecular heterogeneity of tumor cells. The B-cell lymphoma 9 (BCL9) oncogene functions as a transcriptional co-activator of the Wnt/ β-catenin pathway, which plays critical roles in CRC pathogenesis. Here we have identified a β-catenin-independent function of BCL9 in a poor-prognosis subtype of CRC tumors characterized by expression of stromal and neural associated genes. In response to spontaneous calcium transients or cellular stress, BCL9 is recruited adjacent to the interchromosomal regions, where it stabilizes the mRNA of calcium signaling and neural associated genes by interacting with paraspeckle proteins. BCL9 subsequently promotes tumor progression and remodeling of the tumor microenvironment (TME) by sustaining the calcium transients and neurotransmitter-dependent communication among CRC cells. These data provide additional insights into the role of BCL9 in tumor pathogenesis and point towards additional avenues for therapeutic intervention.

Complications in the third trimester were related to disorders of the intestinal SIgA-targeted microbiota.

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