scholarly journals NEK1-mediated retromer trafficking promotes blood–brain barrier integrity by regulating glucose metabolism and RIPK1 activation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Huibing Wang ◽  
Weiwei Qi ◽  
Chengyu Zou ◽  
Zhangdan Xie ◽  
Mengmeng Zhang ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Developmental Disorders ◽  
Brain Barrier ◽  
Endosomal Trafficking ◽  
Loss Of Function ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Blood Brain ◽  
Cerebrovascular Endothelial Cells ◽  
Deficient Mice

AbstractLoss-of-function mutations in NEK1 gene, which encodes a serine/threonine kinase, are involved in human developmental disorders and ALS. Here we show that NEK1 regulates retromer-mediated endosomal trafficking by phosphorylating VPS26B. NEK1 deficiency disrupts endosomal trafficking of plasma membrane proteins and cerebral proteome homeostasis to promote mitochondrial and lysosomal dysfunction and aggregation of α-synuclein. The metabolic and proteomic defects of NEK1 deficiency disrupts the integrity of blood–brain barrier (BBB) by promoting lysosomal degradation of A20, a key modulator of RIPK1, thus sensitizing cerebrovascular endothelial cells to RIPK1-dependent apoptosis and necroptosis. Genetic inactivation of RIPK1 or metabolic rescue with ketogenic diet can prevent postnatal lethality and BBB damage in NEK1 deficient mice. Inhibition of RIPK1 reduces neuroinflammation and aggregation of α-synuclein in the brains of NEK1 deficient mice. Our study identifies a molecular mechanism by which retromer trafficking and metabolism regulates cerebrovascular integrity, cerebral proteome homeostasis and RIPK1-mediated neuroinflammation.

scholarly journals Encephalitic Alphaviruses Exploit Caveola-Mediated Transcytosis at the Blood-Brain Barrier for Central Nervous System Entry

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hamid Salimi ◽  
Matthew D. Cain ◽  
Xiaoping Jiang ◽  
Robyn A. Roth ◽  
Wandy L. Beatty ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Endothelial Cells ◽  
Nervous System ◽  
Viral Replication ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Type I ◽  
Brain Endothelial Cells ◽  
Blood Brain ◽  
Deficient Mice

ABSTRACT Venezuelan and western equine encephalitis viruses (VEEV and WEEV, respectively) invade the central nervous system (CNS) early during infection, via neuronal and hematogenous routes. While viral replication mediates host shutoff, including expression of type I interferons (IFN), few studies have addressed how alphaviruses gain access to the CNS during established infection or the mechanisms of viral crossing at the blood-brain barrier (BBB). Here, we show that hematogenous dissemination of VEEV and WEEV into the CNS occurs via caveolin-1 (Cav-1)-mediated transcytosis (Cav-MT) across an intact BBB, which is impeded by IFN and inhibitors of RhoA GTPase. Use of reporter and nonreplicative strains also demonstrates that IFN signaling mediates viral restriction within cells comprising the neurovascular unit (NVU), differentially rendering brain endothelial cells, pericytes, and astrocytes permissive to viral replication. Transmission and immunoelectron microscopy revealed early events in virus internalization and Cav-1 association within brain endothelial cells. Cav-1-deficient mice exhibit diminished CNS VEEV and WEEV titers during early infection, whereas viral burdens in peripheral tissues remained unchanged. Our findings show that alphaviruses exploit Cav-MT to enter the CNS and that IFN differentially restricts this process at the BBB. IMPORTANCE VEEV, WEEV, and eastern equine encephalitis virus (EEEV) are emerging infectious diseases in the Americas, and they have caused several major outbreaks in the human and horse population during the past few decades. Shortly after infection, these viruses can infect the CNS, resulting in severe long-term neurological deficits or death. Neuroinvasion has been associated with virus entry into the CNS directly from the bloodstream; however, the underlying molecular mechanisms have remained largely unknown. Here, we demonstrate that following peripheral infection alphavirus augments vesicular formation/trafficking at the BBB and utilizes Cav-MT to cross an intact BBB, a process regulated by activators of Rho GTPases within brain endothelium. In vivo examination of early viral entry in Cav-1-deficient mice revealed significantly lower viral burdens in the brain than in similarly infected wild-type animals. These studies identify a potentially targetable pathway to limit neuroinvasion by alphaviruses.

scholarly journals Endosomal trafficking regulates receptor-mediated transcytosis of antibodies across the blood brain barrier

2017 ◽  
Vol 38 (4) ◽  
pp. 727-740 ◽  
Author(s):  
Arsalan S Haqqani ◽  
Christie E Delaney ◽  
Eric Brunette ◽  
Ewa Baumann ◽  
Graham K Farrington ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Blood Brain Barrier ◽  
Early Endosome ◽  
Brain Barrier ◽  
Endosomal Trafficking ◽  
Brain Endothelial Cells ◽  
Density Fractions ◽  
Blood Brain ◽  
Late Endosomes ◽  
Early Endosomes

Current methods for examining antibody trafficking are either non-quantitative such as immunocytochemistry or require antibody labeling with tracers. We have developed a multiplexed quantitative method for antibody ‘tracking’ in endosomal compartments of brain endothelial cells. Rat brain endothelial cells were co-incubated with blood-brain barrier (BBB)-crossing FC5, monovalent FC5Fc or bivalent FC5Fc fusion antibodies and control antibodies. Endosomes were separated using sucrose-density gradient ultracentrifugation and analyzed using multiplexed mass spectrometry to simultaneously quantify endosomal markers, receptor-mediated transcytosis (RMT) receptors and the co-incubated antibodies in each fraction. The quantitation showed that markers of early endosomes were enriched in high-density fractions (HDF), whereas markers of late endosomes and lysosomes were enriched in low-density fractions (LDF). RMT receptors, including transferrin receptor, showed a profile similar to that of early endosome markers. The in vitro BBB transcytosis rates of antibodies were directly proportional to their partition into early endosome fractions of brain endothelial cells. Addition of the Fc domain resulted in facilitated antibody ‘redistribution’ from LDF into HDF and additionally into multivesicular bodies (MVB). Sorting of various FC5 antibody formats away from late endosomes and lysosomes and into early endosomes and a subset of MVB results in increased antibody transcytosis at the abluminal side of the BBB.

scholarly journals Impaired blood–brain barrier function in angiotensinogen-deficient mice

10.1038/2070 ◽  
1998 ◽  
Vol 4 (9) ◽  
pp. 1078-1080 ◽  
Author(s):  
Yoshihiko Kakinuma ◽  
Hiroshi Hama ◽  
Fumihiro Sugiyama ◽  
Ken-ichi Yagami ◽  
Katsutoshi Goto ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Barrier Function ◽  
Brain Barrier ◽  
Blood Brain ◽  
Deficient Mice

scholarly journals Size-selective loosening of the blood-brain barrier in claudin-5–deficient mice

2003 ◽  
Vol 161 (3) ◽  
pp. 653-660 ◽  
Author(s):  
Takehiro Nitta ◽  
Masaki Hata ◽  
Shimpei Gotoh ◽  
Yoshiteru Seo ◽  
Hiroyuki Sasaki ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Endothelial Cells ◽  
Nervous System ◽  
Blood Vessels ◽  
Tight Junctions ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Blood Brain ◽  
The Central Nervous System ◽  
Deficient Mice

Tight junctions are well-developed between adjacent endothelial cells of blood vessels in the central nervous system, and play a central role in establishing the blood-brain barrier (BBB). Claudin-5 is a major cell adhesion molecule of tight junctions in brain endothelial cells. To examine its possible involvement in the BBB, claudin-5–deficient mice were generated. In the brains of these mice, the development and morphology of blood vessels were not altered, showing no bleeding or edema. However, tracer experiments and magnetic resonance imaging revealed that in these mice, the BBB against small molecules (<800 D), but not larger molecules, was selectively affected. This unexpected finding (i.e., the size-selective loosening of the BBB) not only provides new insight into the basic molecular physiology of BBB but also opens a new way to deliver potential drugs across the BBB into the central nervous system.

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