5 research outputs found
Ethanol Induced Brain Lipid Changes in Mice Assessed by Mass Spectrometry
Alcohol abuse is a chronic disease
characterized by the consumption
of alcohol at a level that interferes with physical and mental health
and causes serious and persistent changes in the brain. Lipid metabolism
is of particular interest due to its high concentration in the brain.
Lipids are the main component of cell membranes, are involved in cell
signaling, signal transduction, and energy storage. In this study,
we analyzed lipid composition of chronically ethanol exposed mouse
brains. Juvenile (JUV) and adult (ADU) mice were placed on a daily
limited-access ethanol intake model for 52 days. After euthanasia,
brains were harvested, and total lipids were extracted from brain
homogenates. Samples were analyzed using high resolution mass spectrometry
and processed by multivariate and univariate statistical analysis.
Significant lipid changes were observed in different classes including
sphingolipids, fatty acids, lysophosphatidylcholines, and other glycerophospholipids
Novel Bivalent Ligands Based on the Sumanirole Pharmacophore Reveal Dopamine D<sub>2</sub> Receptor (D<sub>2</sub>R) Biased Agonism
The
development of bivalent ligands has attracted interest as a
way to potentially improve the selectivity and/or affinity for a specific
receptor subtype. The ability to bind two distinct receptor binding
sites simultaneously can allow the selective activation of specific
G-protein dependent or β-arrestin-mediated cascade pathways.
Herein, we developed an extended SAR study using sumanirole (<b>1</b>) as the primary pharmacophore. We found that substitutions
in the <i>N</i>-1- and/or <i>N</i>-5-positions,
physiochemical properties of those substituents, and secondary aromatic
pharmacophores can enhance agonist efficacy for the cAMP inhibition
mediated by G<sub>i/o</sub>-proteins, while reducing or suppressing
potency and efficacy toward β-arrestin recruitment. Compound <b>19</b> was identified as a new lead for its selective D<sub>2</sub> G-protein biased agonism with an EC<sub>50</sub> in the subnanomolar
range. Structure–activity correlations were observed between
substitutions in positions <i>N</i>-1 and/or <i>N</i>-5 of <b>1</b> and the capacity of the new bivalent compounds
to selectively activate G-proteins versus β-arrestin recruitment
in D<sub>2</sub>R-BRET functional assays
Novel Bivalent Ligands Based on the Sumanirole Pharmacophore Reveal Dopamine D<sub>2</sub> Receptor (D<sub>2</sub>R) Biased Agonism
The
development of bivalent ligands has attracted interest as a
way to potentially improve the selectivity and/or affinity for a specific
receptor subtype. The ability to bind two distinct receptor binding
sites simultaneously can allow the selective activation of specific
G-protein dependent or β-arrestin-mediated cascade pathways.
Herein, we developed an extended SAR study using sumanirole (<b>1</b>) as the primary pharmacophore. We found that substitutions
in the <i>N</i>-1- and/or <i>N</i>-5-positions,
physiochemical properties of those substituents, and secondary aromatic
pharmacophores can enhance agonist efficacy for the cAMP inhibition
mediated by G<sub>i/o</sub>-proteins, while reducing or suppressing
potency and efficacy toward β-arrestin recruitment. Compound <b>19</b> was identified as a new lead for its selective D<sub>2</sub> G-protein biased agonism with an EC<sub>50</sub> in the subnanomolar
range. Structure–activity correlations were observed between
substitutions in positions <i>N</i>-1 and/or <i>N</i>-5 of <b>1</b> and the capacity of the new bivalent compounds
to selectively activate G-proteins versus β-arrestin recruitment
in D<sub>2</sub>R-BRET functional assays
Chronic Ethanol Consumption Profoundly Alters Regional Brain Ceramide and Sphingomyelin Content in Rodents
Ceramides
(CER) are involved in alcohol-induced neuroinflammation.
In a mouse model of chronic alcohol exposure, 16 CER and 18 sphingomyelin
(SM) concentrations from whole brain lipid extracts were measured
using electrospray mass spectrometry. All 18 CER concentrations in
alcohol exposed adults increased significantly (range: 25–607%);
in juveniles, 6 CER decreased (range: −9 to −37%). In
contrast, only three SM decreased in adult and one increased significantly
in juvenile. Next, regional identification at 50 μm spatial
resolution from coronal sections was obtained with matrix implanted
laser desorption/ionization mass spectrometry imaging (MILDI-MSI)
by implanting silver nanoparticulate matrices followed by focused
laser desorption. Most of the CER and SM quantified in whole brain
extracts were detected in MILDI images. Coronal sections from three
brain levels show qualitative regional changes in CER-SM ion intensities,
as a function of group and brain region, in cortex, striatum, accumbens,
habenula, and hippocampus. Highly correlated changes in certain white
matter CER-SM pairs occur in regions across all groups, including
the hippocampus and the lateral (but not medial) cerebellar cortex
of adult mice. Our data provide the first microscale MS evidence of
regional lipid intensity variations induced by alcohol
Mass Spectrometric Imaging of Ceramide Biomarkers Tracks Therapeutic Response in Traumatic Brain Injury
Traumatic
brain injury (TBI) is a serious public health problem
and the leading cause of death in children and young adults. It also
contributes to a substantial number of cases of permanent disability.
As lipids make up over 50% of the brain mass and play a key role in
both membrane structure and cell signaling, their profile is of particular
interest. In this study, we show that advanced mass spectrometry imaging
(MSI) has sufficient technical accuracy and reproducibility to demonstrate
the anatomical distribution of 50 μm diameter microdomains that
show changes in brain ceramide levels in a rat model of controlled
cortical impact (CCI) 3 days post injury with and without treatment.
Adult male Sprague–Dawley rats received one strike and were
euthanized 3 days post trauma. Brain MS images showed increase in
ceramides in CCI animals compared to control as well as significant
reduction in ceramides in CCI treated animals, demonstrating therapeutic
effect of a peptide agonist. The data also suggests the presence of
diffuse changes outside of the injured area. These results shed light
on the extent of biochemical and structural changes in the brain after
traumatic brain injury and could help to evaluate the efficacy of
treatments