Extracellular vesicles play crucial roles in intercellular communication in the tumor microenvironment. Here we demonstrate that in hepatic fibrosis, TGF-β stimulates the palmitoylation of hexokinase 1 (HK1) in hepatic stellate cells (HSCs), which facilitates the secretion of HK1 via large extracellular vesicles in a TSG101-dependent manner. The large extracellular vesicle HK1 is hijacked by hepatocellular carcinoma (HCC) cells, leading to accelerated glycolysis and HCC progression. In HSCs, the nuclear receptor Nur77 transcriptionally activates the expression of depalmitoylase ABHD17B to inhibit HK1 palmitoylation, consequently attenuating HK1 release. However, TGF-β-activated Akt functionally represses Nur77 by inducing Nur77 phosphorylation and degradation. We identify the small molecule PDNPA that binds Nur77 to generate steric hindrance to block Akt targeting, thereby disrupting Akt-mediated Nur77 degradation and preserving Nur77 inhibition of HK1 release. Together, this study demonstrates an overlooked function of HK1 in HCC upon its release from HSCs and highlights PDNPA as a candidate compound for inhibiting HCC progression.
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http://dx.doi.org/10.1038/s42255-022-00642-5 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Biology, Indiana University, Bloomington, IN 47405.
Transgenic expression of a double-stranded RNA in plants can induce silencing of homologous mRNAs in fungal pathogens. Although such host-induced gene silencing is well documented, the molecular mechanisms by which RNAs can move from the cytoplasm of plant cells across the plasma membrane of both the host cell and fungal cell are poorly understood. Indirect evidence suggests that this RNA transfer may occur at a very early stage of the infection process, prior to breach of the host cell wall, suggesting that silencing RNAs might be secreted onto leaf surfaces.
View Article and Find Full Text PDFActa Neurochir (Wien)
January 2025
Department of Neurosurgery, University Hospital Eppendorf, Hamburg, Germany.
In recent years, it has been increasingly recognized that tumor growth relies not only on support from the surrounding microenvironment but also on the tumors capacity to adapt to - and actively manipulate - its niche. While targeting angiogenesis and modulating the local immune environment have been explored as therapeutic approaches, these strategies have yet to yield effective treatments for brain tumors and remain under refinement. More recently, the nervous system itself has been explored as a critical environmental support for cancer, with extensive neuro-tumoral interactions observed both intracranially and in extracranial sites containing neural components.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
VIB-UGent Center for Inflammation Research, Ghent, Belgium.
Background: The brain is shielded from the peripheral circulation by central nervous system (CNS) barriers, comprising the well-known blood-brain barrier (BBB) and the less recognized blood-cerebrospinal fluid (CSF) barrier located within the brain ventricles. The gut microbiota represents a diverse and dynamic population of microorganisms that can influence the health of the host, including the development of neurological disorders like Alzheimer's disease (AD). However, the intricate mechanisms governing the interplay between the gut and brain remain elusive, and the means by which gut-derived signals traverse the CNS barriers remain unclear.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Queen's University, Kingston, ON, Canada; D'OR Institute for Research and Education, Rio de Janeiro, Rio de Janeiro, Brazil.
Background: Physical exercise improves overall brain health, cognition, and stimulates the release of extracellular vesicles (EVs) in humans. Exercise upregulates irisin, a myokine derived from fibronectin type III domain-containing protein 5 (FNDC5) previously shown to mediate the beneficial actions of exercise on memory in mouse models of Alzheimer's disease (AD). Here, we investigated if physical exercise upregulates EVs.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Taipei Medical University, Taipei, Taiwan.
Understanding the physiological connection between platelets and brain function reveals new paradigms in neurodegenerative disease treatment. Platelets, traditionally associated with hemostasis, but also sometimes regarded as a mirror of neurons in the blood circulation, also encompass a spectrum of neurobiological roles, including neuroinflammation modulation, neurogenesis, and synaptic remodeling. These roles are primarily mediated through a rich array of bioactive molecules and extracellular vesicles (EVs), capable of traversing the blood-brain barrier.
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