69 research outputs found
JCB904687 Supplemental Material3 - Supplemental material for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins
No full textSupplemental material, JCB904687 Supplemental Material3 for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins by Lars Winkler, Rosel Blasig, Olga Breitkreuz-Korff, Philipp Berndt, Sophie Dithmer, Hans C Helms, Dmytro Puchkov, Kavi Devraj, Mehmet Kaya, Zhihai Qin, Stefan Liebner, Hartwig Wolburg, Anuska V Andjelkovic, Andre Rex, Ingolf E Blasig and Reiner F Haseloff in Journal of Cerebral Blood Flow & Metabolism</p
JCB904687 Supplemental Material1 - Supplemental material for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins
No full textSupplemental material, JCB904687 Supplemental Material1 for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins by Lars Winkler, Rosel Blasig, Olga Breitkreuz-Korff, Philipp Berndt, Sophie Dithmer, Hans C Helms, Dmytro Puchkov, Kavi Devraj, Mehmet Kaya, Zhihai Qin, Stefan Liebner, Hartwig Wolburg, Anuska V Andjelkovic, Andre Rex, Ingolf E Blasig and Reiner F Haseloff in Journal of Cerebral Blood Flow & Metabolism</p
JCB904687 Supplemental Material2 - Supplemental material for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins
No full textSupplemental material, JCB904687 Supplemental Material2 for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins by Lars Winkler, Rosel Blasig, Olga Breitkreuz-Korff, Philipp Berndt, Sophie Dithmer, Hans C Helms, Dmytro Puchkov, Kavi Devraj, Mehmet Kaya, Zhihai Qin, Stefan Liebner, Hartwig Wolburg, Anuska V Andjelkovic, Andre Rex, Ingolf E Blasig and Reiner F Haseloff in Journal of Cerebral Blood Flow & Metabolism</p
JCB904687 Supplemental Material4 - Supplemental material for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins
No full textSupplemental material, JCB904687 Supplemental Material4 for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins by Lars Winkler, Rosel Blasig, Olga Breitkreuz-Korff, Philipp Berndt, Sophie Dithmer, Hans C Helms, Dmytro Puchkov, Kavi Devraj, Mehmet Kaya, Zhihai Qin, Stefan Liebner, Hartwig Wolburg, Anuska V Andjelkovic, Andre Rex, Ingolf E Blasig and Reiner F Haseloff in Journal of Cerebral Blood Flow & Metabolism</p
JCB904687 Supplemental Material5 - Supplemental material for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins
No full textSupplemental material, JCB904687 Supplemental Material5 for Tight junctions in the blood–brain barrier promote edema formation and infarct size in stroke – Ambivalent effects of sealing proteins by Lars Winkler, Rosel Blasig, Olga Breitkreuz-Korff, Philipp Berndt, Sophie Dithmer, Hans C Helms, Dmytro Puchkov, Kavi Devraj, Mehmet Kaya, Zhihai Qin, Stefan Liebner, Hartwig Wolburg, Anuska V Andjelkovic, Andre Rex, Ingolf E Blasig and Reiner F Haseloff in Journal of Cerebral Blood Flow & Metabolism</p
Evolution of a novel gene pair from a canonical toxin-antitoxin module in Escherichia coli
No full textFree-living bacteria are continuously subjected to environmental stress. This stress can be in the form of a change in temperature, pH, osmolarity or nutritional starvation. Most bacterial species contain gene modules known as Toxin-Antitoxin (TA) systems that reversibly inhibit cellular growth in response to stress; thereby helping the cells cope with a changing environment. One mechanism that bacteria have developed to combat fluctuations in environmental temperature is the cold-shock response. This response helps exponentially growing cells buffer themselves against a downshift in temperature from their optimal growing temperature; typically a shift from 37??C to 15??C for Escherichia coli (E. coli). Cold-shock proteins (Csp) are synthesized at this time. Protein Y (PY), the protein product of gene yfiA in E. coli is suggested to be a cold-shock related protein. It prevents ribosomes from dissociation during cold-shock, and in stationary phase, thereby blocking translational elongation and inhibiting cell growth. This mechanism resembled that of a typical TA system toxin. We identified a small gene, b2596, upstream of yfiA and propose that the b2596-yfiA module evolved from a true proteic TA system that functioned in cold-shock conditions; Protein X (PX), product of b2596, being the antitoxin and PY the toxin. The module still retains some of its TA system characteristics: both genes encode small proteins, have opposing charges and show sequence similarity to known TA genes. Also, like a true TA system b2596, the proposed antitoxin gene, precedes yfiA, the proposed toxin gene. However, we found that the two genes have independent transcriptional start sites. Also b2596 encodes a leaderless mRNA with UUG start and thus we predict that it cannot be translated well in vivo. PY inhibits growth of E. coli cells and functions in helping the bacterial population to survive cold-shock. Our data suggest that b2596 and yfiA have evolved from a canonical proteic TA module that was functional in cold shock. The two genes are now independent and responsive to cold shock.M.S.Includes bibliographical references (p. 56-60)
HIF-1 alpha is involved in blood-brain barrier dysfunction and paracellular migration of bacteria in pneumococcal meningitis
No full textBacterial meningitis is a deadly disease most commonly caused by Streptococcus pneumoniae, leading to severe neurological sequelae including cerebral edema, seizures, stroke, and mortality when untreated. Meningitis is initiated by the transfer of S. pneumoniae from blood to the brain across the blood-cerebrospinal fluid barrier or the blood-brain barrier (BBB). The underlying mechanisms are still poorly understood. Current treatment strategies include adjuvant dexamethasone for inflammation and cerebral edema, followed by antibiotics. The success of dexamethasone is however inconclusive, necessitating new therapies for controlling edema, the primary reason for neurological complications. Since we have previously shown a general activation of hypoxia inducible factor (HIF-1α) in bacterial infections, we hypothesized that HIF-1α, via induction of vascular endothelial growth factor (VEGF) is involved in transmigration of pathogens across the BBB. In human, murine meningitis brain samples, HIF-1α activation was observed by immunohistochemistry. S. pneumoniae infection in brain endothelial cells (EC) resulted in in vitro upregulation of HIF-1α/VEGF (Western blotting/qRT-PCR) associated with increased paracellular permeability (fluorometry, impedance measurements). This was supported by bacterial localization at cell-cell junctions in vitro and in vivo in brain ECs from mouse and humans (confocal, super-resolution, electron microscopy, live-cell imaging). Hematogenously infected mice showed increased permeability, S. pneumoniae deposition in the brain, along with upregulation of genes in the HIF-1α/VEGF pathway (RNA sequencing of brain microvessels). Inhibition of HIF-1α with echinomycin, siRNA in bEnd5 cells or using primary brain ECs from HIF-1α knock-out mice revealed reduced endothelial permeability and transmigration of S. pneumoniae. Therapeutic rescue using the HIF-1α inhibitor echinomycin resulted in increased survival and improvement of BBB function in S. pneumoniae-infected mice. We thus demonstrate paracellular migration of bacteria across BBB and a critical role for HIF-1α/VEGF therein and hence propose targeting this pathway to prevent BBB dysfunction and ensuing brain damage in infections
Wnt activation of immortalized brain endothelial cells as a tool for generating a standardized model of the blood brain barrier in vitro
No full textReproducing the characteristics and the functional responses of the blood–brain barrier (BBB) in vitro represents an important task for the research community, and would be a critical biotechnological breakthrough. Pharmaceutical and biotechnology industries provide strong demand for inexpensive and easy-to-handle in vitro BBB models to screen novel drug candidates. Recently, it was shown that canonical Wnt signaling is responsible for the induction of the BBB properties in the neonatal brain microvasculature in vivo. In the present study, following on from earlier observations, we have developed a novel model of the BBB in vitro that may be suitable for large scale screening assays. This model is based on immortalized endothelial cell lines derived from murine and human brain, with no need for co-culture with astrocytes. To maintain the BBB endothelial cell properties, the cell lines are cultured in the presence of Wnt3a or drugs that stabilize β-catenin, or they are infected with a transcriptionally active form of β-catenin. Upon these treatments, the cell lines maintain expression of BBB-specific markers, which results in elevated transendothelial electrical resistance and reduced cell permeability. Importantly, these properties are retained for several passages in culture, and they can be reproduced and maintained in different laboratories over time. We conclude that the brain-derived endothelial cell lines that we have investigated gain their specialized characteristics upon activation of the canonical Wnt pathway. This model may be thus suitable to test the BBB permeability to chemicals or large molecular weight proteins, transmigration of inflammatory cells, treatments with cytokines, and genetic manipulation
Regulation of the blood-brain barrier function by peripheral cues in health and disease
No full text<jats:title>Abstract</jats:title>
<jats:p>The blood-brain barrier (BBB) is formed by microvascular endothelial cells which are ensembled with pericytes, astrocytes, microglia and neurons in the neurovascular unit (NVU) that is crucial for neuronal function. Given that the NVU and the BBB are highly dynamic and regulated structures, their integrity is continuously challenged by intrinsic and extrinsic factors. Herein, factors from peripheral organs such as gonadal and adrenal hormones may influence vascular function also in CNS endothelial cells in a sex- and age-dependent manner. The communication between the periphery and the CNS likely takes place in specific areas of the brain among which the circumventricular organs have a central position due to their neurosensory or neurosecretory function, owing to physiologically leaky blood vessels. In acute and chronic pathological conditions like liver, kidney, pulmonary disease, toxins and metabolites are generated that reach the brain via the circulation and may directly or indirectly affect BBB functionality via the activation of the immunes system. For example, chronic kidney disease (CKD) currently affects more than 840 million people worldwide and is likely to increase along with western world comorbidities of the cardio-vascular system in continuously ageing societies. Toxins leading to the uremic syndrome, may further lead to neurological complications such as cognitive impairment and uremic encephalopathy. Here we summarize the effects of hormones, toxins and inflammatory reactions on the brain vasculature, highlighting the urgent demand for mechanistically exploring the communication between the periphery and the CNS, focusing on the BBB as a last line of defense for brain protection.</jats:p>
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