Nanosensors for the Chemical Imaging of Acetylcholine Using Magnetic Resonance Imaging

A suite of imaging tools for detecting specific chemicals in the central nervous system could accelerate the understanding of neural signaling events critical to brain function and disease. Here, we introduce a class of nanoparticle sensors for the highly specific detection of acetylcholine in the living brain using magnetic resonance imaging. The nanosensor is composed of acetylcholine-catalyzing enzymes and pH-sensitive gadolinium contrast agents co-localized onto the surface of polymer nanoparticles, which leads to changes in <i>T</i>₁ relaxation rate (1/<i>T</i>₁). The mechanism of the sensor involves the enzymatic hydrolysis of acetylcholine leading to a localized decrease in pH which is detected by the pH-sensitive gadolinium chelate. The concomitant change in 1/<i>T</i>₁ <i>in vitro</i> measured a 20% increase from 0 to 10 μM acetylcholine concentration. The applicability of the nanosensors <i>in vivo</i> was demonstrated in the rat medial prefrontal cortex showing distinct changes in 1/<i>T</i>₁ induced by pharmacological stimuli. The highly specific acetylcholine nanosensor we present here offers a promising strategy for detection of cholinergic neurotransmission and will facilitate our understanding of brain function through chemical imaging

Synthesis, Characterization, and X‑ray Attenuation Properties of Ultrasmall BiOI Nanoparticles: Toward Renal Clearable Particulate CT Contrast Agents

A unique decelerated hydrolytic procedure is developed and reported here for the preparation of ultrasmall nanoparticles (NPs) of PVP-coated BiOI with a narrow size distribution, i.e., 2.8 ± 0.5 nm. The crystal structure of this compound is determined by X-ray powder diffraction using the bulk materials. The stability, cytotoxicity, and potential use of the PVP-coated ultrasmall BiOI NPs as a CT contrast agent are investigated. Because of the combined X-ray attenuation effect of bismuth and iodine, such NPs exhibit a CT value that is among the best of those of the inorganic nanoparticle-based CT contrast agents reported in the literature

Synthesis, Characterization, and X‑ray Attenuation Properties of Ultrasmall BiOI Nanoparticles: Toward Renal Clearable Particulate CT Contrast Agents

A unique decelerated hydrolytic procedure is developed and reported here for the preparation of ultrasmall nanoparticles (NPs) of PVP-coated BiOI with a narrow size distribution, i.e., 2.8 ± 0.5 nm. The crystal structure of this compound is determined by X-ray powder diffraction using the bulk materials. The stability, cytotoxicity, and potential use of the PVP-coated ultrasmall BiOI NPs as a CT contrast agent are investigated. Because of the combined X-ray attenuation effect of bismuth and iodine, such NPs exhibit a CT value that is among the best of those of the inorganic nanoparticle-based CT contrast agents reported in the literature

High fat-induced expression of inflammatory cytokines and chemokines is attenuated in caspase-1 knockout mice.

<p>Inflammatory cytokine/chemokine production in the liver is associated the early stages of NASH. mRNA expression for Tnfα (A), Mcp-1 (B) and F4/80 (C) in the liver of wild-type mice on control or high fat diets was performed by RT-PCR. Values represent means ± SEM. Values with different superscripts are significantly different from one another (<i>p</i><0.05). n = 4 control, n = 6 high fat.</p

Adiposity is increased in caspase-1 knockout mice.

<p>Mice on the control and high fat diets were analyzed for body adiposity. Fat content of subcutaneous (B) and visceral (C) depots were calculated from three images. Total adipose volume was calculated from subcutaneous and visceral depots (D). Adiposity was normalized to body weight and expressed as% adipose (E). Lean mass was calculated based on the density of adipose tissue and normalized to body weight and expressed as% lean mass (F). Values represent means ± SEM. Values with different superscripts are significantly different from one another (<i>p</i><0.05). n = 5 C57BL/6, n = 4 <i>Casp1^-/-</i>.</p

High fat-induced expression of lipogenesis-related genes is attenuated in caspase-1 knockout mice.

<p>Expression of mRNA for Pparγ, Srebp1c, Acc1, Fas and Scd1 were analyzed in the livers of wild-type and <i>Casp1^-/-</i> mice on high fat diets and normalized to 18S. Hepatic expression of phospho-ACC and total ACC were analyzed by western blot (A). Expression of Pparα, Aox, L-fabp, Cpt1α, Pgc1β, Lcad and Mcad were analyzed in the livers of wild-type and Casp1-/- mice on high fat diet and normalized to 18S (B). Apob and Mttp mRNA were measured (C) in the liver of wild-type compared to and Casp1-/- mice on control or high fat diets and normalized to 18S (C). Values represent means ± SEM. Values with + different superscripts are significantly different from wild-type mice on control diet one another (p<0.05). Values with * are significantly different from wild-type mice on high fat diet (p<0.05). n = 4 control, n = 6 high fat.</p

Histopathological analysis of mice on the high fat diet.

<p>Pathologist: BPG. Data are represented as Mean ± SEM.</p><p>H&E slides of the livers of mice on the control and high fat diets were analyzed for steatosis, inflammation, and ballooning. H&E sections were scored in a blinded fashion by BPG. Values represent means ± SEM. n = 4 control, n = 6 high fat.</p

Caspase-1 knockout mice are protected from high fat-induced hepatic steatosis.

<p>Representative images of H&E stained livers in wild-type and <i>Casp1^-/-</i> mice on control or high fat diet (10x) (A). NAFLD activity score of wild-type and <i>Casp1^-/-</i> mice on the high fat diet was assessed by histopathology of H&E stained livers in a blinded-fashion by BPG (B). Hepatic triglyceride (TG) levels were measured biochemically from mice on the control or high fat diets (C). Plasma alanine aminotransferase (ALT) levels were analyzed from mice on the control or high fat diets (D). Plasma cholesterol (E), FFA (F) and TG levels (G) were measured biochemically as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056100#s2" target="_blank">methods</a> section. Values represent means ± SEM. Values with different superscripts are significantly different from one another (<i>p</i><0.05). n = 4 control, n = 6 high fat.</p

Caspase-1 and IL-1β expression is increased after high fat feeding.

<p>Livers of wild-type mice on the control or high fat diet were analyzed for pro-caspase-1 and IL-1β expression by immunoblot (A). Densitometric analysis was done for each protein normalized to HSC70 (B and C). mRNA for IL-1 expression in the liver of mice on the control or high fat diet was analyzed by RT-PCR (D). IL-1 was assessed by ELISA in whole liver tissue (E). Values with different superscripts are significantly different from one another (<i>p</i><0.05). n = 4 control, n = 6 high fat.</p

Comparison of mean regional nT1 values from the upper and lower lung regions for the CF patients and healthy volunteers.

<p>A significant reduction in mean (SD) nT1 (**p = 0.001) was observed in the upper right (UR) [.914 (.037)] and upper left (UL) [0.906 (.040)] lung regions (black bars) for the CF patients (n = 10) in comparison to the healthy control subjects (n = 5) UR [.983 (.003)] and UL [0.984 (.011)] lung regions (open bars). The mean nT1 in the lower right (LR) and lower left (LL) lung regions was also significantly reduced for the CF patients in comparison to healthy volunteers (*p<0.05). Importantly, these differences were observed despite normal spirometry in both groups.</p