30 research outputs found
Small-molecule G-quadruplex stabilizers reveal a novel pathway of autophagy regulation in neurons
International audienc
Conformational transitions of a semiflexible polymer in nematic solvents
Conformations of a single semiflexible polymer chain dissolved in a low
molecular weight liquid crystalline solvents (nematogens) are examined by using
a mean field theory. We takes into account a stiffness and partial
orientational ordering of the polymer. As a result of an anisotropic coupling
between the polymer and nematogen, we predict a discontinuous (or continuous)
phase transition from a condensed-rodlike conformation to a swollen-one of the
polymer chain, depending on the stiffness of the polymer. We also discuss the
effects of the nematic interaction between polymer segments.Comment: 4 pages, 4 figure
Alpha Adrenergic Induction of Transport of Lysosomal Enzyme across the Blood-Brain Barrier.
The impermeability of the adult blood-brain barrier (BBB) to lysosomal enzymes impedes the ability to treat the central nervous system manifestations of lysosomal storage diseases. Here, we found that simultaneous stimulation of the alpha1 and alpha2 adrenoreceptor restores in adult mice the high rate of transport for the lysosomal enzyme P-GUS that is seen in neonates but lost with development. Beta adrenergics, other monoamines, and acetylcholine did not restore this transport. A high dose (500 microg/mouse) of clonidine, a strong alpha2 and weak alpha1 agonist, was able to act as monotherapy in the stimulation of P-GUS transport. Neither use of alpha1 plus alpha2 agonists nor the high dose clonidine disrupted the BBB to albumin. In situ brain perfusion and immunohistochemistry studies indicated that adrengerics act on transporters already at the luminal surface of brain endothelial cells. These results show that adrenergic stimulation, including monotherapy with clonidine, could be key for CNS enzyme replacement therapy
Insular gray matter volume and objective quality of life in schizophrenia
Improving quality of life has been recognized as an important outcome for schizophrenia treatment, although the fundamental determinants are not well understood. In this study, we investigated the association between brain structural abnormalities and objective quality of life in schizophrenia patients. Thirty-three schizophrenia patients and 42 age-, sex-, and education-matched healthy participants underwent magnetic resonance imaging. The Quality of Life Scale was used to measure objective quality of life in schizophrenia patients. Voxel-based morphometry was performed to identify regional brain alterations that correlate with Quality of Life Scale score in the patient group. Schizophrenia patients showed gray matter reductions in the frontal, temporal, limbic, and subcortical regions. We then performed voxel-based multiple regression analysis in these regions to identify any correlations between regional gray matter volume and Quality of Life Scale scores. We found that among four subcategories of the scale, the Instrumental Role category score correlated with gray matter volume in the right anterior insula in schizophrenia patients. In addition, this correlation was shown to be mediated by negative symptoms. Our findings suggest that the neural basis of objective quality of life might differ topographically from that of subjective QOL in schizophrenia
Mannose 6-Phosphate Receptorâmediated Transport of Sulfamidase Across the Bloodâbrain Barrier in the Newborn Mouse
Regulation of autophagy by DNA G-quadruplexes
International audienceGuanine-rich DNA strands can form secondary structures known as G-quadruplexes (G4-DNA). G4-DNA is important for the regulation of replication and transcription. We recently showed that the expression of Atg7, a gene that is critical for macroautophagy/autophagy, is controlled by G4-DNA in neurons. We demonstrated that the transcription factor SUB1/PC4 and the G4-DNA-specific antibody HF2 bind to a putative G4-DNA motif located in the Atg7 gene. Stabilizing G4-DNA with the G4-ligand pyridostatin (PDS) downregulates Atg7 expression in neurons. Here, we further investigated how G4-DNA in the Atg7 gene is stabilized by PDS. We show that PDS can form 1:1 and 2:1 complexes with the Atg7's G4. We also demonstrate that PDS downregulates the ATG7 protein and the expression of Atg7 in astrocytes as well as in neurons. Together with our previous findings, these data establish a novel G4-DNA-associated mechanism of autophagy regulation at a transcriptional level in neurons and astrocytes
Sex differences in a murine model of Cerebral Amyloid Angiopathy
Cerebral amyloid angiopathy (CAA) is one of the common causes of lobar intracerebral hemorrhage and vascular cognitive impairment (VCI) in the aging population. Increased amyloid plaque deposition within cerebral blood vessels, specifically the smooth muscle layer, is linked to increased cerebral microbleeds (CMBs) and impaired cognition in CAA. Studies in Alzheimerâs disease (AD) have shown that amyloid plaque pathology is more prevalent in the brains of elderly women (2/3rd of the dementia population) compared with men, however, there is a paucity of studies on sex differences in CAA. The objective of this study was to discern the sexual dichotomies in CAA. We utilized male and female Tg-SwDI mice (mouse model of CAA) at 12â14 months of age for this study. We evaluated sex differences in CMBs, cognitive function and inflammation. Cognition was assessed using Y-maze (spatial working memory) and Fear Conditioning (contextual memory). CMBs were quantified by ex vivo brain MRI scans. Inflammatory cytokines in brain were quantified using ELISA. Our results demonstrated that aging Tg-SwDI female mice had a significantly higher burden of CMBs on MRI as compared to males. Interestingly, these aging Tg-SwDI female mice also had significantly impaired spatial and contextual memory on Y maze and Fear Conditioning respectively. Furthermore, female mice had significantly lower circulating inflammatory cytokines, IL-1α, IL-2, IL-9, and IFN-Îł, as compared to males. Our results demonstrate that aging female Tg-SwDI mice are more cognitively impaired and have higher number of CMBs, as compared to males at 12â14 months of age. This may be secondary to reduced levels of neural repair cytokines (IL-1α, IL-2, IL-9 and IFN-Îł) involved in sex specific inflammatory signaling in CAA
Combined effect of alpha1 (cirazoline) and alpha2 (clonidine) adrenergic receptor agonists on I-PGUS transport across the BBB.
<p>Neither drug alone affected I-PGUS uptake, but combined they effectively increased transport across the BBB. ***p<0.001 in comparison to control; n = 12/group.</p
Dose response curve for clonidine: Effect on I-PGUS BBB transport.
<p>A high dose of clonidine enhanced I-PGUS transport without disrupting the BBB. *p<0.05 in comparison to control; n = 10/group.</p