Membraneless cytoplasmic condensates of mRNAs and proteins, known as RNA granules, play pivotal roles in the regulation of mRNA fate. Their maintenance fine-tunes time and location of protein expression, affecting many cellular processes, which require complex protein distribution. Here, we report that RNA granules-monitored by DEAD-Box helicase 6 (DDX6)-disassemble during neuronal maturation both in cell culture and in vivo.
View Article and Find Full Text PDFPTEN-induced kinase 1 (PINK1) is a short-lived protein required for the removal of damaged mitochondria through Parkin translocation and mitophagy. Because the short half-life of PINK1 limits its ability to be trafficked into neurites, local translation is required for this mitophagy pathway to be active far from the soma. The Pink1 transcript is associated and cotransported with neuronal mitochondria.
View Article and Find Full Text PDFis an ectoparasitic mite causing devastating damages to honey bee colonies around the world. Its impact is considered a major factor contributing to the significant seasonal losses of colonies recorded every year. Beekeepers usually rely on a reduced set of acaricides to manage the parasite, usually the pyrethroids tau-fluvalinate or flumethrin, the organophosphate coumaphos, and the formamidine amitraz.
View Article and Find Full Text PDFmRNA transport restricts translation to specific subcellular locations, which is the basis for many cellular functions. However, the precise process of mRNA sorting to synapses in neurons remains elusive. Here we use Rgs4 mRNA to investigate 3'-UTR-dependent transport by MS2 live-cell imaging.
View Article and Find Full Text PDFBackground: Dendritic messenger RNA (mRNA) localization and subsequent local translation in dendrites critically contributes to synaptic plasticity and learning and memory. Little is known, however, about the contribution of RNA-binding proteins (RBPs) to these processes in vivo.
Results: To delineate the role of the double-stranded RBP Staufen2 (Stau2), we generate a transgenic rat model, in which Stau2 expression is conditionally silenced by Cre-inducible expression of a microRNA (miRNA) targeting Stau2 mRNA in adult forebrain neurons.
In polarized cells, such as neurons, the synthesis of an mRNA does not ensure its proper cellular expression. Most mature transcripts require the association with RNA-binding proteins, resulting in the formation of RNA granules, which are then transported within the cytoplasm along the cytoskeleton and delivered to their proper subcellular locations, where they can be locally translated. Here we review current microscopy methods that have been developed to visualize RNA granule formation, transport and translation at the single cell level with a special emphasis on the MS2 and SunTag systems.
View Article and Find Full Text PDFBackground: Parastomal hernia is a very common complication after stoma formation. Current surgical techniques for repairing parastomal hernia have unsatisfactory results. We aim to assess our preliminary experience with prophylactic mesh placement at the time of stoma formation.
View Article and Find Full Text PDFLoss of ER Ca homeostasis triggers endoplasmic reticulum (ER) stress and drives ER-PM contact sites formation in order to refill ER-luminal Ca. Recent studies suggest that the ER stress sensor and mediator of the unfolded protein response (UPR) PERK regulates intracellular Ca fluxes, but the mechanisms remain elusive. Here, using proximity-dependent biotin identification (BioID), we identified the actin-binding protein Filamin A (FLNA) as a key PERK interactor.
View Article and Find Full Text PDFNeuronal function is highly sensitive to changes in oxygen levels, but how hypoxia affects dendritic spine formation and synaptogenesis is unknown. Here we report that hypoxia, chemical inhibition of the oxygen-sensing prolyl hydroxylase domain proteins (PHDs), and silencing of Phd2 induce immature filopodium-like dendritic protrusions, promote spine regression, reduce synaptic density, and decrease the frequency of spontaneous action potentials independently of HIF signaling. We identified the actin cross-linker filamin A (FLNA) as a target of PHD2 mediating these effects.
View Article and Find Full Text PDFThe oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network.
View Article and Find Full Text PDFRegulation of cargo transport via adaptor molecules is essential for neuronal development. However, the role of PDZ scaffolding proteins as adaptors in neuronal cargo trafficking is still poorly understood. Here, we show by genetic deletion in mice that the multi-PDZ domain scaffolding protein glutamate receptor interacting protein 1 (GRIP1) is required for dendrite development.
View Article and Find Full Text PDFVessel sprouting by migrating tip and proliferating stalk endothelial cells (ECs) is controlled by genetic signals (such as Notch), but it is unknown whether metabolism also regulates this process. Here, we show that ECs relied on glycolysis rather than on oxidative phosphorylation for ATP production and that loss of the glycolytic activator PFKFB3 in ECs impaired vessel formation. Mechanistically, PFKFB3 not only regulated EC proliferation but also controlled the formation of filopodia/lamellipodia and directional migration, in part by compartmentalizing with F-actin in motile protrusions.
View Article and Find Full Text PDFNMDA type glutamate receptors (NMDARs) are best known for their role in synaptogenesis and synaptic plasticity. Much less is known about their developmental role before neurons form synapses. We report here that VEGF, which promotes migration of granule cells (GCs) during postnatal cerebellar development, enhances NMDAR-mediated currents and Ca(2+) influx in immature GCs before synapse formation.
View Article and Find Full Text PDFCerebral ischemia stimulates endogenous neurogenesis. However, the functional relevance of this phenomenon remains unclear because of poor survival and low neuronal differentiation rates of newborn cells. Therefore, further studies on mechanisms regulating neurogenesis under ischemic conditions are required, among which ephrin-ligands and ephrin-receptors (Eph) are an interesting target.
View Article and Find Full Text PDFGrowing axons are guided to their targets by attractive and repulsive cues. In the developing spinal cord, Netrin-1 and Shh guide commissural axons toward the midline. However, the combined inhibition of their activity in commissural axon turning assays does not completely abrogate turning toward floor plate tissue, suggesting that additional guidance cues are present.
View Article and Find Full Text PDFPolarization of tumor-associated macrophages (TAMs) to a proangiogenic/immune-suppressive (M2-like) phenotype and abnormal, hypoperfused vessels are hallmarks of malignancy, but their molecular basis and interrelationship remains enigmatic. We report that the host-produced histidine-rich glycoprotein (HRG) inhibits tumor growth and metastasis, while improving chemotherapy. By skewing TAM polarization away from the M2- to a tumor-inhibiting M1-like phenotype, HRG promotes antitumor immune responses and vessel normalization, effects known to decrease tumor growth and metastasis and to enhance chemotherapy.
View Article and Find Full Text PDFThe role of pericytes in the control of blood-brain barrier (BBB) integrity has remained enigmatic. In this issue, Bell et al. and two concurrent studies highlight that pericyte loss causes BBB breakdown and hypoperfusion.
View Article and Find Full Text PDFArterioscler Thromb Vasc Biol
September 2010
Objective: To study whether Notch signaling, which regulates cell fate decisions and vessel morphogenesis, controls lymphatic development.
Methods And Results: In zebrafish embryos, sprouts from the axial vein have lymphangiogenic potential because they give rise to the first lymphatics. Knockdown of delta-like-4 (Dll4) or its receptors Notch-1b or Notch-6 in zebrafish impaired lymphangiogenesis.
Although the nervous and vascular systems are functionally different, they show a high degree of anatomic parallelism and cross-talk. They also share similar mechanisms and molecular cues that regulate their development and maintenance. Malfunctioning of this cross-talk can cause or influence several vascular and neuronal disorders.
View Article and Find Full Text PDFArterioscler Thromb Vasc Biol
May 2009
Filopodia, "the fingers that do the walking," have been identified on endothelial cells at the tip of sprouting vessels for half a century, but the key role of the tip cell in vessel branching has been recognized only in the past few years. A model is emerging, whereby tip cells lead the way in a branching vessel, stalk cells elongate the sprout, and a very recently discovered phalanx cell ensures quiescence and perfusion of the newly formed branch. Recent genetic studies have shed light on the molecular signature of these distinct endothelial phenotypes; this provides a novel conceptual framework of how vessel morphogenesis occurs.
View Article and Find Full Text PDFPigment epithelium-derived factor (PEDF) combines neurotrophic, neuroprotective, anti-angiogenic, anti-tumor and neural stem cell self-renewal properties in a single molecule, making this protein a valuable potential therapeutic agent. We herein analyzed the expression of human recombinant full-length PEDF, and its N- and C-terminal regions (amino acids 1-243 and 195-418, respectively) in three mammalian cell lines (HEK-293T, COS-1, and 26HCMsv), and in the yeast Pichia pastoris. The highest production of recombinant PEDF was achieved in P.
View Article and Find Full Text PDFDendritic spines are small protrusions emerging from dendrites that receive excitatory input. The process of spine morphogenesis occurs both in the developing brain and during synaptic plasticity. Molecules regulating the cytoskeleton are involved in spine formation and maintenance.
View Article and Find Full Text PDF