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The pro-oncogenic noncanonical activity of a RAS•GTP:RanGAP1 complex facilitates nuclear protein export.
No full textCanonical RAS signaling, including PI3K/AKT- and RAF/MEK-dependent activities, results mainly from RAS•GTP interaction with its effectors at the plasma membrane. Here, we identified a fundamental, oncogenic, noncanonical RAS•GTP activity that increases XPO1-dependent export of nuclear protein cargo into the cytoplasm and is independent of PI3K/AKT and RAF/MEK signaling. This RAS-dependent step acts downstream from XPO1 binding to nuclear protein cargo and is mediated by a perinuclear protein complex between RAS•GTP and RanGAP1 that facilitates hydrolysis of Ran•GTP to Ran•GDP, which promotes release of nuclear protein cargo into the cytoplasm. The export of nuclear EZH2, which promotes cytoplasmic degradation of the DLC1 tumor suppressor protein, is a biologically important component of this pro-oncogenic activity. Conversely, preventing nuclear protein export contributes to the antitumor activity of KRAS inhibition, which can be further augmented by reactivating the tumor suppressor activity of DLC1 or potentially combining RAS inhibitors with other cancer treatments
Reply to: Understanding virologic heterogeneity in chronic hepatitis B treatment
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Metabolic remodeling in hiPSC-derived myofibers carrying the m.3243A>G mutation.
No full textMutations in mitochondrial DNA cause severe multisystem disease frequently associated with muscle weakness. The m.3243A>G mutation is the major cause of mitochondrial encephalomyopathy lactic acidosis and stroke-like episodes (MELAS). Experimental models that recapitulate the disease phenotype in vitro for disease modeling or drug screening are very limited. We have therefore generated hiPSC-derived muscle fibers with variable heteroplasmic mtDNA mutation load without significantly affecting muscle differentiation potential. The cells exhibit physiological characteristics of muscle fibers and show a well-organized myofibrillar structure. In cells carrying the m.3243A>G mutation, the mitochondrial membrane potential and oxygen consumption were reduced in relation to the mutant load. We have shown through proteomic, phosphoproteomic, and metabolomic analyses that the m.3243A>G mutation variably affects the cell phenotype in relation to the mutant load. This variation is reflected by an increase in the NADH/NAD+ ratio, which in turn influences key nutrient-sensing pathways in the myofibers. This model enables a detailed study of the impact of the mutation on cellular bioenergetics and on muscle physiology with the potential to provide a platform for drug screening
LATTICE: A federation solution scalable to UK research linking technical capability and information governance
No full textThis white paper outlines LATTICE, a proposed federation solution that the Crick has developed to enable Trusted Research Environments (TRES) and Secure Data Environments (SDEs) / Safe Havens to federate. It provides a solution to bring together data from different Data Zone curators (SDEs / Safe havens / Bespoke sets), matched to a single approach to Information Governance. This design has been shared with the UK research community through multiple channels, and which has gained traction as the target for the NHS OneLondon SN-SDE and other external environments. LATTICE is built to operate at scale, and is designed to pragmatically integrate existing investments.
The LATTICE platform integrates a small set of hyperscale, enterprise solutions to provide a tailorable, repeatable and secure fabric for projects to quickly convert approved projects into scientific outputs and societal gain. Delivering the fastest (and speeding up) “time to research” is a unique selling point and one that offers £100m in value for money returns.</p
Assessment of CRB1-associated retinopathies using the S-MAIA fast protocol and spectral-domain optical coherence tomography.
No full textBackground: A cross-sectional study was conducted at Moorfields Eye Hospital, UK, involving patients with CRB1-associated retinopathies: macular dystrophy (MD), cone-rod dystrophy (CORD), and early-onset severe retinal dystrophy/Leber congenital amaurosis (EOSRD/LCA). The study aimed to evaluate CRB1-associated retinopathies using microperimetry (macular integrity assessment (S-MAIA) fast protocol) and spectral domain optical coherence tomography (SD-OCT). Methods: Data quality and participant attrition were assessed in 18 patients (10 MD, 5 EOSRD/LCA, 3 CORD), aged 10-52 years, with a median best corrected visual acuity (BCVA) of 0.41 logMAR. Results: Microperimetry and SD-OCT data were obtained from 14 and 18 patients, respectively, but eccentric fixation hindered structure-function analysis. All participants showed overall abnormal sensitivity on the S-MAIA fast protocol. Parafoveal volume was significantly increased, while foveal thickness and volume were reduced compared to normative data (p < 0.01). Conclusions: This study highlights the challenges of participant attrition and the need for alternative functional metrics to complement traditional evaluations. It also reinforces previous findings of abnormal retinal architecture in CRB1-associated retinopathies, providing further insights into S-MAIA and SD-OCT assessments for this patient population
A stable NTN1 fluorescent reporter chicken reveals cell specific molecular signatures during optic fissure closure.
No full textNTN1 is expressed in a wide range of developmental tissues and is essential for normal development. Here we describe the generation of a Netrin-1 reporter chicken line (NTN1-T2A-eGFP) by targeting green fluorescent protein into the NTN1 locus using CRISPR/Cas9 methodology. Our strategy gave 100% transmission of heterozygous (NTN1T2A - eGFP/+) embryos in which GFP localisation faithfully replicated endogenous NTN1 expression in the optic fissure and neural tube floorplate. Furthermore, all NTN1T2A - eGFP/+ embryos and hatched birds appeared phenotypically normal. We applied this resource to a pertinent developmental context - coloboma is a structural eye malformation characterised by failure of epithelial fusion during optic fissure closure (OFC) and NTN1 is specifically expressed in fusion pioneer cells at the edges of the optic fissure. We therefore optimised the isolation of GFP expressing cells from embryonic NTN1T2A - eGFP/+ eyes using spectral fluorescence cell-sorting and applied transcriptomic profiling of pioneer cells, which revealed multiple new OFC markers and novel pathways for developmental tissue fusion and coloboma. This work provides a novel fluorescent NTN1 chicken reporter line with broad experimental utility and is the first to directly molecularly characterise pioneer cells during OFC
Elevated plasma matrix metalloproteinases are associated with Mycobacterium tuberculosis bloodstream infection and mortality in human immunodeficiency virus-associated tuberculosis.
No full textMortality from human immunodeficiency virus (HIV)-associated tuberculosis (TB) is high, particularly among hospitalized patients. In 433 people with HIV hospitalized with symptoms of TB, we investigated plasma matrix metalloproteinases (MMP) and matrix-derived biomarkers in relation to TB diagnosis, mortality, and Mycobacterium tuberculosis (Mtb) bloodstream infection (BSI). Compared to other diagnoses, MMP-8 was elevated in confirmed TB and in Mtb-BSI, positively correlating with extracellular matrix breakdown products. Baseline MMP-3, -7, -8, -10, and PIIINP were associated with Mtb-BSI and 12-week mortality. These findings implicate MMP dysregulation in pathophysiology of advanced HIV-TB and support MMP inhibition as a host-directed therapeutic strategy for HIV-TB.</p
Mixed alkyl/aryl phosphonates identify metabolic serine hydrolases as antimalarial targets.
No full textMalaria, caused by Plasmodium falciparum, remains a significant health burden. One major barrier for developing antimalarial drugs is the ability of the parasite to rapidly generate resistance. We previously demonstrated that salinipostin A (SalA), a natural product, potently kills parasites by inhibiting multiple lipid metabolizing serine hydrolases, a mechanism that results in a low propensity for resistance. Given the difficulty of employing natural products as therapeutic agents, we synthesized a small library of lipidic mixed alkyl/aryl phosphonates as bioisosteres of SalA. Two constitutional isomers exhibited divergent antiparasitic potencies that enabled the identification of therapeutically relevant targets. The active compound kills parasites through a mechanism that is distinct from both SalA and the pan-lipase inhibitor orlistat and shows synergistic killing with orlistat. Our compound induces only weak resistance, attributable to mutations in a single protein involved in multidrug resistance. These data suggest that mixed alkyl/aryl phosphonates are promising, synthetically tractable antimalarials
DNGR-1 regulates proliferation and migration of bone marrow dendritic cell progenitors.
No full textConventional dendritic cells (cDCs) are sentinel cells that play a crucial role in both innate and adaptive immune responses. cDCs originate from a progenitor (pre-cDC) in the bone marrow (BM) that travels via the blood to seed peripheral tissues before locally differentiating into functional cDC1 and cDC2 cells, as part of a process known as cDCpoiesis. How cDCpoiesis is regulated and whether this affects the output of cDCs is poorly understood. In this study, we show that DNGR-1, an innate immune receptor expressed by cDC progenitors and type 1 cDCs, can regulate cDCpoiesis in mice. In a competitive chimera setting, cDC progenitors lacking DNGR-1 exhibit increased proliferation and tissue migratory potential. Compared with their WT counterparts, DNGR-1-deficient cDC progenitor cells display superior colonization of peripheral tissues but an altered distribution. These findings suggest that cDCpoiesis can be regulated in part by precursor cell-intrinsic processes driven by signals from innate immune receptors such as DNGR-1 that may respond to alterations in the BM milieu
β-catenin/TCF4/NANOG axis controls miR-302 transcription in colorectal cancer cells
No full textThe miR-302 cluster, a key pluripotency-associated non-coding RNA, has been implicated in stem cell homeostasis and tumourigenesis. However, its regulatory mechanisms in cancers, including colorectal cancer (CRC) remain poorly understood. Here, we demonstrate that the β-catenin/TCF4 complex significantly enhances miR-302 expression through direct promoter activation in CRC cells. We hypothesized that the β-catenin/TCF4 complex directly activates the miR-302 promoter and cooperates with NANOG in a transcriptional feedback loop sustaining stem-like traits in CRC cells. Using a combination of promoter-driven luciferase reporter assays, chromatin immunoprecipitation (ChIP), and molecular dynamics simulations, we identify a regulatory axis involving Wnt signalling and the transcription factor NANOG. Our data show that individual members of the miR-302 cluster activate the NANOG promoter, while both NANOG and β-catenin/TCF4 synergistically enhance miR-302 promoter activity, suggesting the presence of a positive feedback loop. Structural simulations further elucidate the binding interactions between TCF4, NANOG, and the miR-302 promoter, corroborating our experimental observations. Together, these findings position miR-302 as a downstream effector of Wnt/β-catenin signalling and an integral component of NANOG-mediated transcriptional networks in CRC stem-like cells. This work advances our understanding of non-coding RNA regulation in cancer and highlights potential therapeutic opportunities for targeting stemness-associated pathways