Although fluorescence microscopy provides a crucial window into the physiology of living specimens, many biological processes are too fragile, are too small, or occur too rapidly to see clearly with ...existing tools. We crafted ultrathin light sheets from two-dimensional optical lattices that allowed us to image three-dimensional (3D) dynamics for hundreds of volumes, often at subsecond intervals, at the diffraction limit and beyond. We applied this to systems spanning four orders of magnitude in space and time, including the diffusion of single transcription factor molecules in stem cell spheroids, the dynamic instability of mitotic microtubules, the immunological synapse, neutrophil motility in a 3D matrix, and embryogenesis in Caenorhabditis elegans and Drosophila melanogaster. The results provide a visceral reminder of the beauty and the complexity of living systems.
Hypoxia induces a vast array of long noncoding RNAs (lncRNA) in breast cancer cells, but their biological functions remain largely unknown. Here, we identified a hitherto uncharacterized ...hypoxia-induced lncRNA RAB11B-AS1 in breast cancer cells. RAB11B-AS1 is a natural lncRNA upregulated in human breast cancer and its expression is induced by hypoxia-inducible factor 2 (HIF2), but not HIF1, in response to hypoxia. RAB11B-AS1 enhanced the expression of angiogenic factors including VEGFA and ANGPTL4 in hypoxic breast cancer cells by increasing recruitment of RNA polymerase II. In line with increased angiogenic factors, conditioned media from RAB11B-AS1-overexpressing breast cancer cells promoted tube formation of human umbilical vein endothelial cells
. Gain- and loss-of-function studies revealed that RAB11B-AS1 increased breast cancer cell migration and invasion
and promoted tumor angiogenesis and breast cancer distant metastasis without affecting primary tumor growth in mice. Taken together, these findings uncover a fundamental mechanism of hypoxia-induced tumor angiogenesis and breast cancer metastasis. SIGNIFICANCE: This study reveals the molecular mechanism by which the lncRNA RAB11B-AS1 regulates hypoxia-induced angiogenesis and breast cancer metastasis, and provides new insights into the functional interaction between a lncRNA and tumor microenvironment. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/5/964/F1.large.jpg.
RNA granules have been likened to liquid droplets whose dynamics depend on the controlled dissolution and condensation of internal components. The molecules and reactions that drive these dynamics in ...vivo are not well understood. In this study, we present evidence that a group of intrinsically disordered, serine-rich proteins regulate the dynamics of P granules in C. elegans embryos. The MEG (maternal-effect germline defective) proteins are germ plasm components that are required redundantly for fertility. We demonstrate that MEG-1 and MEG-3 are substrates of the kinase MBK-2/DYRK and the phosphatase PP2A(PPTR-½). Phosphorylation of the MEGs promotes granule disassembly and dephosphorylation promotes granule assembly. Using lattice light sheet microscopy on live embryos, we show that GFP-tagged MEG-3 localizes to a dynamic domain that surrounds and penetrates each granule. We conclude that, despite their liquid-like behavior, P granules are non-homogeneous structures whose assembly in embryos is regulated by phosphorylation.
Plasmacytoid dendritic cells (pDCs) were initially considered as critical for innate immunity to viruses. However, our group has shown that pDCs bind to and inhibit the growth of Aspergillus ...fumigatus hyphae and that depletion of pDCs renders mice hypersusceptible to experimental aspergillosis. In this study, we examined pDC receptors contributing to hyphal recognition and downstream events in pDCs stimulated by A. fumigatus hyphae. Our data show that Dectin-2, but not Dectin-1, participates in A. fumigatus hyphal recognition, TNF-α and IFN-α release, and antifungal activity. Moreover, Dectin-2 acts in cooperation with the FcRγ chain to trigger signaling responses. In addition, using confocal and electron microscopy we demonstrated that the interaction between pDCs and A. fumigatus induced the formation of pDC extracellular traps (pETs) containing DNA and citrullinated histone H3. These structures closely resembled those of neutrophil extracellular traps (NETs). The microarray analysis of the pDC transcriptome upon A. fumigatus infection also demonstrated up-regulated expression of genes associated with apoptosis as well as type I interferon-induced genes. Thus, human pDCs directly recognize A. fumigatus hyphae via Dectin-2; this interaction results in cytokine release and antifungal activity. Moreover, hyphal stimulation of pDCs triggers a distinct pattern of pDC gene expression and leads to pET formation.
Influenza infection increases the incidence of myocardial infarction but the reason is unknown. Platelets mediate vascular occlusion through thrombotic functions but are also recognized to have ...immunomodulatory activity. To determine if platelet processes are activated during influenza infection, we collected blood from 18 patients with acute influenza infection. Microscopy reveals activated platelets, many containing viral particles and extracellular-DNA associated with platelets. To understand the mechanism, we isolate human platelets and treat them with influenza A virus. Viral-engulfment leads to C3 release from platelets as a function of TLR7 and C3 leads to neutrophil-DNA release and aggregation. TLR7 specificity is confirmed in murine models lacking the receptor, and platelet depletion models support platelet-mediated C3 and neutrophil-DNA release post-influenza infection. These findings demonstrate that the initial intrinsic defense against influenza is mediated by platelet-neutrophil cross-communication that tightly regulates host immune and complement responses but can also lead to thrombotic vascular occlusion.
Magnetic resonance imaging proton density fat fraction (MRI-PDFF) offers promise as a non-invasive biomarker of treatment response in early-phase nonalcoholic steatohepatitis (NASH) trials. We ...performed a systematic review to quantify the association between a ≥ 30% reduction in MRI-PDFF and histologic response in NASH.
We searched the Cochrane Library, Embase, Medline and trial registries through May 2020 for early-phase clinical trials that incorporated MRI-PDFF and examined histologic response following intervention in adults with NASH. Subjects were classified as MRI-PDFF responders (relative decline in liver fat ≥30%) or non-responders (relative decline in liver fat <30%). MRI-PDFF responders versus non-responders were compared. Primary outcome was histologic response defined as a 2-point improvement in NAFLD Activity Score with at least 1-point improvement in lobular inflammation or ballooning. Secondary outcome was NASH resolution. Proportions and random effects odds ratios (OR) with corresponding 95% confidence intervals (CI) were calculated.
Seven studies met inclusion criteria, comprising 346 subjects (median age 51 years; 59% female; 46% with diabetes). MRI-PDFF responders were significantly more likely to have a histologic response (51% vs 14%, P < .001; OR 6.98, 95% CI 2.38-20.43, P < .001) and NASH resolution (41% vs 7%, P < .001; OR 5.45, 95% CI 1.53-19.46, P = .009) compared to non-responders.
This meta-analysis demonstrates that a ≥30% relative decline in MRI-PDFF is associated with higher odds of histologic response and NASH resolution. These results support the use of MRI-PDFF in non-invasive monitoring of treatment response in early-phase NASH clinical trials and provide helpful data for sample-size estimation for histology-based assessment.
Altered epigenetic reprogramming contributes to breast cancer progression and metastasis. How the epigenetic reader mediates breast cancer progression remains poorly understood. Here, we showed that ...the epigenetic reader zinc finger MYND-type containing 8 (ZMYND8) is induced by HIF-1 and HIF-2 in breast cancer cells and also upregulated in human breast tumors, and is correlated with poor survival of patients with breast cancer. Genetic deletion of ZMYND8 decreases breast cancer cell colony formation, migration, and invasion in vitro, and inhibits breast tumor growth and metastasis to the lungs in mice. The ZMYND8's oncogenic effect in breast cancer requires HIF-1 and HIF-2. We further showed that ZMYND8 interacts with HIF-1α and HIF-2α and enhances elongation of the global HIF-induced oncogenic genes by increasing recruitment of BRD4 and subsequent release of paused RNA polymerase II in breast cancer cells. ZMYND8 acetylation at lysines 1007 and 1034 by p300 is required for HIF activation and breast cancer progression and metastasis. These findings uncover a primary epigenetic mechanism of HIF activation and HIF-mediated breast cancer progression, and discover a possible molecular target for the diagnosis and treatment of breast cancer.
Immune checkpoint inhibitors (ICIs) are monoclonal antibodies targeting immune checkpoint molecules. ICIs are an immunotherapy for the treatment of many advanced malignancies. The advent of ICIs has ...been a major breakthrough in the field of oncology, a fact recognized by the 2018 Nobel Prize in Physiology or Medicine being awarded for the discovery. The Food and Drug Administration approved the first ICI, ipilimumab, in 2011 for the treatment of metastatic melanoma. Seven ICIs are now used in clinical practice, including nivolumab and pembrolizumab for treatment of advanced hepatocellular carcinoma. ICIs are increasingly used across the spectrum of hepatobiliary neoplasia. The utility of ICI therapy has been limited by immune‐related adverse reactions (irAEs) affecting multiple organ systems. Hepatotoxicity is an important irAE, occurring in up to 16% of patients receiving ICIs. Optimizing outcomes in patients receiving ICI therapy requires awareness of and familiarity with diagnosing and management of ICI‐induced immune‐mediated hepatotoxicity (IMH), including approaches to treatment and ICI dose management. The aim of this review article is to (1) provide a comprehensive, evidence‐based review of IMH; (2) perform a systematic review of the management of IMH; and (3) present algorithms for the diagnosis and management of IMH.
This review describes an adult rat model of status epilepticus (SE) induced by diisopropyl fluorophosphate (DFP), and the beneficial outcomes of transient inhibition of the prostaglandin-E2 receptor ...EP2 with a small molecule antagonist, delayed by 2–4 h after SE onset. Administration of six doses of the selective EP2 antagonist TG6-10-1 over a 2–3 day period accelerates functional recovery, attenuates hippocampal neurodegeneration, neuroinflammation, gliosis and blood-brain barrier leakage, and prevents long-term cognitive deficits without blocking SE itself or altering acute seizure characteristics. This work has provided important information regarding organophosphate-induced seizure related pathologies in adults and revealed the effectiveness of delayed EP2 inhibition to combat these pathologies.
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