RESUMO
Acute myeloid leukaemia (AML) represents a set of heterogeneous myeloid malignancies, and hallmarks include mutations in epigenetic modifiers, transcription factors and kinases1-5. The extent to which mutations in AML drive alterations in chromatin 3D structure and contribute to myeloid transformation is unclear. Here we use Hi-C and whole-genome sequencing to analyse 25 samples from patients with AML and 7 samples from healthy donors. Recurrent and subtype-specific alterations in A/B compartments, topologically associating domains and chromatin loops were identified. RNA sequencing, ATAC with sequencing and CUT&Tag for CTCF, H3K27ac and H3K27me3 in the same AML samples also revealed extensive and recurrent AML-specific promoter-enhancer and promoter-silencer loops. We validated the role of repressive loops on their target genes by CRISPR deletion and interference. Structural variation-induced enhancer-hijacking and silencer-hijacking events were further identified in AML samples. Hijacked enhancers play a part in AML cell growth, as demonstrated by CRISPR screening, whereas hijacked silencers have a downregulating role, as evidenced by CRISPR-interference-mediated de-repression. Finally, whole-genome bisulfite sequencing of 20 AML and normal samples revealed the delicate relationship between DNA methylation, CTCF binding and 3D genome structure. Treatment of AML cells with a DNA hypomethylating agent and triple knockdown of DNMT1, DNMT3A and DNMT3B enabled the manipulation of DNA methylation to revert 3D genome organization and gene expression. Overall, this study provides a resource for leukaemia studies and highlights the role of repressive loops and hijacked cis elements in human diseases.
Assuntos
Genoma Humano , Leucemia Mieloide Aguda , Humanos , Cromatina/genética , Metilação de DNA , Leucemia Mieloide Aguda/genética , Genoma Humano/genética , Regiões Promotoras Genéticas , Elementos Facilitadores Genéticos , Inativação Gênica , Reprodutibilidade dos Testes , Sistemas CRISPR-Cas , Análise de Sequência , DNA (Citosina-5-)-Metiltransferases , Regulação Leucêmica da Expressão GênicaRESUMO
BACKGROUND: Ischemic stroke (IS) occurs when a blood vessel supplying the brain becomes obstructed, resulting in cerebral ischemia. This type of stroke accounts for approximately 87% of all strokes. Globally, IS leads to high mortality and poor prognosis and is associated with neuroinflammation and neuronal apoptosis. D-allose is a bio-substrate of glucose that is widely expressed in many plants. Our previous study showed that D-allose exerted neuroprotective effects against acute cerebral ischemic/reperfusion (I/R) injury by reducing neuroinflammation. Here, we aimed to clarify the beneficial effects D-allose in suppressing IS-induced neuroinflammation damage, cytotoxicity, neuronal apoptosis and neurological deficits and the underlying mechanism in vitro and in vivo. METHODS: In vivo, an I/R model was induced by middle cerebral artery occlusion and reperfusion (MCAO/R) in C57BL/6 N mice, and D-allose was given by intraperitoneal injection within 5 min after reperfusion. In vitro, mouse hippocampal neuronal cells (HT-22) with oxygen-glucose deprivation and reperfusion (OGD/R) were established as a cell model of IS. Neurological scores, some cytokines, cytotoxicity and apoptosis in the brain and cell lines were measured. Moreover, Gal-3 short hairpin RNAs, lentiviruses and adeno-associated viruses were used to modulate Gal-3 expression in neurons in vitro and in vivo to reveal the molecular mechanism. RESULTS: D-allose alleviated cytotoxicity, including cell viability, LDH release and apoptosis, in HT-22 cells after OGD/R, which also alleviated brain injury, as indicated by lesion volume, brain edema, neuronal apoptosis, and neurological functional deficits, in a mouse model of I/R. Moreover, D-allose decreased the release of inflammatory factors, such as IL-1ß, IL-6 and TNF-α. Furthermore, the expression of Gal-3 was increased by I/R in wild-type mice and HT-22 cells, and this factor further bound to TLR4, as confirmed by three-dimensional structure prediction and Co-IP. Silencing the Gal-3 gene with shRNAs decreased the activation of TLR4 signaling and alleviated IS-induced neuroinflammation, apoptosis and brain injury. Importantly, the loss of Gal-3 enhanced the D-allose-mediated protection against I/R-induced HT-22 cell injury, inflammatory insults and apoptosis, whereas activation of TLR4 by the selective agonist LPS increased the degree of neuronal injury and abolished the protective effects of D-allose. CONCLUSIONS: In summary, D-allose plays a crucial role in inhibiting inflammation after IS by suppressing Gal-3/TLR4/PI3K/AKT signaling pathway in vitro and in vivo.
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It has been shown that Hi-C can be used as a powerful tool to detect structural variations (SVs) and enhancer hijacking events. However, there has been no existing programs that can directly visualize and detect such events on a personal computer, which hinders the broad adaption of the technology for intuitive discovery in cancer studies. Here, we introduce the EagleC Explorer, a desktop software that is specifically designed for exploring Hi-C and other chromatin contact data in cancer genomes. EagleC Explorer has a set of unique features, including 1) conveniently visualizing global and local Hi-C data; 2) interactively detecting SVs on a Hi-C map for any user-selected region on screen within seconds, using a deep-learning model; 3) reconstructing local Hi-C map surrounding user-provided SVs and generating publication-quality figures; 4) detecting enhancer hijacking events for any user-suggested regions on screen. In addition, EagleC Explorer can also incorporate other genomic tracks such as RNA-Seq or ChIP-Seq to facilitate scientists for integrative data analysis and making novel discoveries.
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The immediate processing of whole blood specimen is required in circulating tumor cell-based liquid biopsy. Reliable blood specimen stabilization towards preserving circulating tumor cells can enable more extensive geographic sharing for precise rare-cell technology, but remains challenging due to the fragility and rarity of circulating tumor cells. Herein, we establish a zwitterionic magnetic microgel platform to stabilize whole blood specimen for long-term hypothermic preservation of model circulating tumor cells. We show in a cohort study of 20 cancer patients that blood samples can be preserved for up to 7 days without compromising circulating tumor cell viability and RNA integrity, thereby doubling the viable preservation duration. We demonstrate that the 7-day microgel-preserved blood specimen is able to reliably detect cancer-specific transcripts, similar to fresh blood specimens, while there are up/down expression regulation of 1243 genes in model circulating tumor cells that are preserved by commercial protectant. Mechanistically, we find that the zwitterionic microgel assembly counters the cold-induced excessive reactive oxygen species and platelet activation, as well as extracellular matrix loss-induced cell anoikis, to prevent circulating tumor cell loss in the whole blood sample. The present work could prove useful for the development of blood-based noninvasive diagnostics.
Assuntos
Microgéis , Células Neoplásicas Circulantes , Humanos , Estudos de Coortes , Anoikis , Matriz ExtracelularRESUMO
Ischemic stroke is an acute brain disease with a high mortality rate. Currently, the only effective method is to restore the blood supply. But the inflammation and oxidative stress induced by this approach can damage the integrity of the endothelial system, which hampers the patient's outcome. d-allose has the biological activity to protect against ischemia-reperfusion injury, however, the underlying mechanism remains unclear. Here, brain microvascular endothelial cells (RBMECs) were used as the study material to establish an IR-injury model. Cell viability of RBMECs was suppressed after hypoxia/reoxygenation (H/R) treatment and significantly increased after d-allose supplementation. RNAseq results showed 180 differentially expressed genes (DEGs) between the therapy group (H/R + Dal) and the model group (H/R), of which 151 DEGs were restored to control levels by d-allose. Enrichment analysis revealed that DEGs were mainly involved in protein processing in endoplasmic reticulum. 6 DEGs in the unfolded protein response (UPR) pathway were verified by qRT-PCR. All of them were significantly down-regulated by d-allose, indicating that endoplasmic reticulum stress (ERS) was relieved. In addition, d-allose significantly inhibited the phosphorylation level of eIF2α, a marker of ERS. The downstream molecules of Phosphorylation of eIF2α, Gadd45a and Chac1, which trigger cycle arrest and apoptosis, respectively, were also significantly inhibited by d-allose. Thus, we conclude that d-allose inhibits the UPR pathway, attenuates eIF2α phosphorylation and ERS, restores the cell cycle, inhibits apoptosis, and thus enhances endothelial cell tolerance to H/R injury.
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Células Endoteliais , Traumatismo por Reperfusão , Humanos , Células Endoteliais/metabolismo , Estresse do Retículo Endoplasmático , Traumatismo por Reperfusão/metabolismo , Apoptose , Encéfalo/metabolismo , HipóxiaRESUMO
SIGNIFICANCE: Comprehensive profiling of the enhancer landscape and 3D genome structure in liposarcoma identifies extensive enhancer-oncogene coamplification and enhancer hijacking events, deepening the understanding of how oncogenes are regulated in cancer.
Assuntos
Lipossarcoma , Oncogenes , Humanos , Elementos Facilitadores GenéticosRESUMO
Doubling of the optic disc is rare in clinic, which appears as true doubling or pseudo-doubling. Bilateral doubling of the optic discs is even more less seen in clinic. Here, we report the case of a 35-year-old woman who presented to the clinic for a physical examination. The patient's best-corrected visual acuity was 0.6 OD with +2.25 DS/3.50 DC×175°, and 0.9 OS with -3.00 DS/0.50 DC×145°. The intraocular pressure of each eye was normal. Fundoscopy examination revealed an enlarged suspected optic disc in both eyes. Visual field examination revealed an additional blind spot in each eye. Optical coherence tomography (OCT) analysis showed a normal macular thickness and profile. B-scan ultrasound revealed a single optic nerve shadow in each eye. Cranial computed tomography (CT) showed only 1 optic foramen and 1 optic nerve in each eye. Although double-blind spots were demonstrated by visual field examination, and pits in both optic disc regions for both eyes were shown by OCT, it was not enough to support the diagnosis of true doubling of the optic disc. Consequently, the diagnosis of bilateral pseudo-doubling of optic discs was made based on the clinical evidence, leading to the consideration of possible causality of other ophthalmic diseases.
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Disco Óptico , Adulto , Feminino , Humanos , Pressão Intraocular , Disco Óptico/diagnóstico por imagem , Tomografia de Coerência Óptica/métodos , Campos VisuaisRESUMO
The aim of the present study was to evaluate the association between statin use and the risk of age-related macular degeneration (AMD). A systematic search of the PubMed, EMBASE and ISI web of science databases was used to identify eligible published literatures without language restrictions up to April 2015. Summary relative ratios (RRs) and 95% CIs were estimated using a fixed-effect or random-effects model. A total of 14 studies met the inclusion criteria and were included in this meta-analysis. No significant association was observed between statin use and the risk of any AMD (RR, 0.95; 95% CI, 0.74-1.15); and stratified analysis showed that statins had a significantly different effects on early and late stages of AMD. For early AMD, statin use significantly reduced the risk approximately 17% (RR, 0.83; 95% CI, 0.66-0.99). At the late stage, we observed a significant protective association of statin use with exudative AMD (RR, 0.90; 95% CI, 0.80-0.99), in contrast with the absent association between statins and geographic atrophy (RR, 1.16; 95% CI, 0.77-1.56). These results demonstrated that statin use was protective for early and exudative AMD. Additional large prospective cohort studies and RCTs are required to determine the potential effect of statins on AMD prevention.