Biology subjects

Nadel, J.

Publications and source records attributed to Nadel, J..

4 recordsLinked to original sources

bioRxiv2023

Myeloperoxidase activity predicts atherosclerotic plaque disruption and atherothrombosis

BackgroundUnstable atherosclerotic plaque is characterized by increased myeloperoxidase (MPO) activity. As unstable plaque is vulnerable to disruption and ensuing thrombosis, we examined whether plaque MPO activity predicts atherothrombosis in a pre-clinical model and correlates with ruptured human atheroma. MethodsTo assess if plaque MPO activity predicts atherothrombosis, rabbits were subjected to aortic endothelial denudation, cholesterol feeding, in vivo magnetic resonance imaging (MRI) of MPO activity using MPO-Gd (gadolinium), followed by pharmacological triggering of atherothrombosis, histology, and MPO activity determined by liquid chromatography tandem mass spectrometry (LC-MSMS) by quantifying the MPO-specific product of hydroethidine, 2-chloroethidium. To correlate plaque MPO activity to ruptured human atheroma, ex vivo determination of MPO activity by MPO-Gd retention in carotid endarterectomy (CEA) specimens was correlated with in vivo MRI plaque phenotyping in patients, histology, and MPO activity determined by LC-MSMS. ResultsIn rabbits, pre-trigger in vivo MPO activity, validated by LC-MSMS and histology, was higher in thrombosis-prone than thrombosis-resistant plaques and lesion-free segments (R1 relaxation rate = 2.2 {+/-} 0.4 versus 1.6 {+/-} 0.2 and 1.5 {+/-} 0.2 s-1, respectively, p<0.0001), and it predicted atherothrombosis. In CEA specimens, MPO-Gd retention was greater in histologic and MRI-graded American Heart Association (AHA) type VI than types III, IV and V plaques ({Delta}R1 relaxation rate from baseline = 48 {+/-} 6 versus 16 {+/-} 7, 17 {+/-} 8 and 23 {+/-} 8%, respectively, p<0.0001). This association was confirmed by comparing AHA grade to MPO activity determined by LC-MSMS (277 {+/-} 338 versus 7 {+/-} 6, 11 {+/-} 12 and 42 {+/-} 39 pmol 2-chloroethidium/mg protein for type VI versus type III-V plaques, respectively, p=0.0008). ConclusionsMPO activity is elevated in thrombosis-prone rabbit and ruptured human atheroma. Non-invasive molecular imaging of MPO activity predicts atherothrombosis, highlighting the potential of arterial MPO activity to detect vulnerable, destabilized atherosclerosis.

biochemistry↗

bioRxiv2023

Colchicine promotes atherosclerotic plaque stability independently of inflammation

Atherosclerosis is a chronic inflammatory disease which is driven in part by the aberrant trans-differentiation of vascular smooth muscle cells (SMCs). No therapeutic drug has been shown to reverse detrimental SMC-derived cell phenotypes into protective phenotypes, a hypothesized enabler of plaque regression and improved patient outcome. Herein, we describe a novel function of colchicine in the beneficial modulation of SMC-derived cell phenotype, independent of its conventional anti-inflammatory effects. Using SMC fate mapping in an advanced atherosclerotic lesion model, colchicine induced plaque regression by converting pathogenic SMC-derived macrophage-like and osteoblast-like cells into protective myofibroblast-like cells which thickened, and thereby stabilized, the fibrous cap. This was dependent on Notch3 signaling in SMC-derived plaque cells. These findings may help explain the success of colchicine in clinical trials relative to other anti-inflammatory drugs. Thus, we demonstrate the potential of regulating SMC phenotype in advanced plaque regression through Notch3 signaling, in addition to the canonical anti-inflammatory actions of drugs to treat atherosclerosis.

cell biology↗

bioRxiv2023

Distinct Social Behavior and Inter-Brain Connectivity in Dyads with Autistic Individuals

Autism Spectrum Disorder (ASD) is defined by distinctive socio-cognitive behaviors that deviate from typical patterns. Notably, social imitation skills appear to be particularly impacted, manifesting early on in development. This paper compared the behavior and inter-brain dynamics of dyads made up of two typically developing (TD) participants with mixed dyads made up of ASD and TD participants during social imitation tasks. By combining kinematics and EEG-hyperscanning, we show that individuals with ASD exhibited a preference for the follower rather than the lead role in imitating scenarios. Moreover, the study revealed inter-brain synchrony differences, with low-alpha inter-brain synchrony differentiating control and mixed dyads. The studys findings suggest the importance of studying interpersonal phenomena in dynamic and ecological settings and using hyperscanning methods to capture inter-brain dynamics during actual social interactions.

neuroscience↗

bioRxiv2019

Lesion of striatal patches disrupts habitual behaviors and increases behavioral variability

Habits are automated behaviors that are insensitive to changes in behavioral outcomes. Habitual responding is thought to be mediated by striatum, with medial striatum guiding goal-directed action and lateral striatum promoting habits. However, interspersed throughout the striatum are neurochemically differing subcompartments known as patches, which are characterized by distinct molecular profiles relative to the surrounding matrix tissue. These structures have been thoroughly characterized neurochemically and anatomically, but little is known regarding their function. Patches have been shown to be selectively activated during inflexible motor stereotypies elicited by stimulants, suggesting that patches may subserve habitual behaviors. To explore this possibility, we utilized transgenic mice (Sepw1 NP67) expressing Cre recombinase in striatal patches to target these neurons for selective ablation with a virus driving Cre-dependent expression of caspase 3. Mice were then trained to press a lever for sucrose rewards on a variable interval schedule to elicit habitual responding. Mice were not impaired on the acquisition of this task, but lesioning striatal patches disrupted behavioral stability across training and lesioned mice utilized a more goal-directed behavioral strategy during training. Similarly, when mice were forced to omit responses to receive sucrose rewards, habitual responding was impaired in lesioned mice. To rule out effects of lesion on motor behaviors, mice were then tested for impairments in motor learning on a rotarod and locomotion in an open field. We found that patch lesions specifically impaired initial performance on the rotarod without modifying locomotor behaviors in open field. This work indicates that patches promote behavioral stability and habitual responding, adding to a growing literature implicating striatal patches in stimulus-response behaviors.

neuroscience↗