Ketamine Restores Thalamic-Prefrontal Cortex Functional Connectivity in a Mouse Model of Neurodevelopmental Disorder-Associated 2p16.3 Deletion

2p16.3 deletions, involving heterozygous NEUREXIN1 (NRXN1) deletion, dramatically increase the risk of developing neurodevelopmental disorders, including autism and schizophrenia. We have little understanding of how NRXN1 heterozygosity increases the risk of developing these disorders, particularly in terms of the impact on brain and neurotransmitter system function and brain network connectivity. Thus, here we characterize cerebral metabolism and functional brain network connectivity in Nrxn1α heterozygous mice (Nrxn1α+/− mice), and assess the impact of ketamine and dextro-amphetamine on cerebral metabolism in these animals. We show that heterozygous Nrxn1α deletion alters cerebral metabolism in neural systems implicated in autism and schizophrenia including the thalamus, mesolimbic system, and select cortical regions. Nrxn1α heterozygosity also reduces the efficiency of functional brain networks, through lost thalamic “rich club” and prefrontal cortex (PFC) hub connectivity and through reduced thalamic-PFC and thalamic “rich club” regional interconnectivity. Subanesthetic ketamine administration normalizes the thalamic hypermetabolism and partially normalizes thalamic disconnectivity present in Nrxn1α+/− mice, while cerebral metabolic responses to dextro-amphetamine are unaltered. The data provide new insight into the systems-level impact of heterozygous Nrxn1α deletion and how this increases the risk of developing neurodevelopmental disorders. The data also suggest that the thalamic dysfunction induced by heterozygous Nrxn1α deletion may be NMDA receptor-dependent

The differential hormonal milieu of morning versus evening, may have an impact on muscle hypertrophic potential

Substantial gains in muscle strength and hypertrophy are clearly associated with the routine performance of resistance training. What is less evident is the optimal timing of the resistance training stimulus to elicit these significant functional and structural skeletal muscle changes. Therefore, this investigation determined the impact of a single bout of resistance training performed either in the morning or evening upon acute anabolic signalling (insulin-like growth factor-binding protein-3 (IGFBP-3), myogenic index and differentiation) and catabolic processes (cortisol). Twenty-four male participants (age 21.4±1.9yrs, mass 83.7±13.7kg) with no sustained resistance training experience were allocated to a resistance exercise group (REP). Sixteen of the 24 participants were randomly selected to perform an additional non-exercising control group (CP) protocol. REP performed two bouts of resistance exercise (80% 1RM) in the morning (AM: 0800 hrs) and evening (PM: 1800 hrs), with the sessions separated by a minimum of 72 hours. Venous blood was collected immediately prior to, and 5 min after, each resistance exercise and control sessions. Serum cortisol and IGFBP-3 levels, myogenic index, myotube width, were determined at each sampling period. All data are reported as mean ± SEM, statistical significance was set at P≤0.05. As expected a significant reduction in evening cortisol concentration was observed at pre (AM: 98.4±10.5, PM: 49.8±4.4 ng/ml, P0.05). Timing of resistance training regimen in the evening appears to augment some markers of hypertrophic potential, with elevated IGFBP-3, suppressed cortisol and a superior cellular environment. Further investigation, to further elucidate the time course of peak anabolic signalling in morning vs evening training conditions, are timely

<i>L. monocytogenes</i> causes calcium-independent LLO-mediated mast cell degranulation with delayed kinetics.

<p>(A and B) BMMC were incubated for the times indicated with (A) media alone (shaded) or WT <i>L. monocytogenes</i> at the MOI indicated (black line); IgE-loaded cells were unstimulated (shaded) or stimulated with 10 ng/ml antigen (black line); (B) WT or <i>Δhly L. monocytogenes</i> at the MOI indicated. (C) BMMC were incubated for 2 h alone (shaded), or with WT or <i>Δhly L. monocytogenes</i> at MOI 100:1 (black line) in media or calcium-free buffer. IgE-loaded cells were stimulated with 10 ng/ml antigen or PMA/I. CD107a expression levels were determined by flow cytometry. Data are (A and C) representative of 3 independent experiments; (B) mean +/- SEM for 3 independent experiments shown relative to media alone.</p

<i>L. monocytogenes</i> infects mast cells at low levels and survives intracellularly for up to 24 h.

<p>(A) BMMC were incubated with WT or <i>Δhly</i> bacteria for 2 h at MOI 10∶1, washed then transferred to fresh media containing 50 µg/ml gentamicin for 24 h. Cells were stained with anti-<i>Listeria</i> (green), wheat germ agglutinin (red) and DAPI (blue) and analysed by confocal microscopy. Intracellular whole bacteria (unbroken arrow) and bacterial fragments (broken arrow) are indicated. (B) BMMC were incubated with WT, <i>Δhly</i> or EGDe bacteria for 2 h at MOI 1∶1 and 100∶1, washed then transferred to fresh media containing 50 µg/ml gentamicin for the times indicated. At each time point BMMC were washed, lysed and viable intracellular bacteria determined. nd, non detected. Data are (A) representative images of mast cells showing intracellular bacteria from a single experiment; (B) the mean +/- SD from 2 independent experiments.</p

Haematocrit and serum percentage change in Resistance Exercise and Control groups.

<p>Haematocrit and serum percentage change in Resistance Exercise and Control groups.</p

Illustration of the experimental design throughout the current investigation.

<p>After exercise familiarisation and 1RM testing, participants performed the following interventions in a randomised order: REP-AM, REP, PM, CP-AM and CP-PM.</p

<i>L. monocytogenes</i> causes LLO-mediated downregulation of CD117 but not FcεRI on BMMC and decreases chemotaxis.

<p>(A, B and C) BMMC were incubated with WT or <i>Δhly</i> bacteria at the MOI indicated for (A) the times indicated; (B and C) 2 h, then washed and transferred to media containing 50 µg/ml gentamicin for an additional 24 h. Cells were analysed at the time points indicated. CD117 and FcεRI levels were determined by flow cytometry and are shown relative to untreated cells. (D and E) BMMC were incubated with or without WT bacteria at the MOI 10∶1 for 2 h prior transfer to the top section of a transwell. Cells were incubated in the transwells for 4 h in the presence or absence of 10 ng/ml SCF in the bottom compartment. Migration was assessed by counting number of cells per 1000 beads by flow cytometry (D). (E) CD117 levels were determined by flow cytometry in cells incubated in media alone (shaded) or with 10:1 MOI WT bacteria (Black line) for cells incubated with media or in the presence of 10 ng/ml SCF. Data are the mean +/- SEM for 3 (A, B and C); 7 (D); 4 (E) independent experiments. Statistical significance p<0.05 compared to media treatment is indicated (*).</p

Cortisol concentration (nl/mL) pre and post resistance exercise in the morning (0800hrs) and evening (1800hrs).

<p>* denotes significance. Mean ± SEM.</p

Pre and Post percentage change at AM and PM in Insulin-Like Growth Factor Binding Protein-3 concentrations.

<p>* denotes significance. Mean ± SEM.</p

<i>L. monocytogenes</i> causes the release of various cytokines and chemokines from BMMC.

<p>BMMC were incubated with media alone or WT <i>L. monocytogenes</i> at MOI 100:1 for 2 h, washed and transferred to media containing 50 µg/ml gentamicin for an additional 24 h. Cell supernatants were harvested after the initial 2 h and the additional 24 h and mediator release determined by Bio-plex. Concentrations of (A) TNF-α; (B) IL-6 (light grey bars), CCL2 (open bars), CCL3 (dark grey bars) and CCL4 (black bars); (C) IL-2 (light grey bars), GM-CSF (dark grey bars) and CCL5 (open bars); (D) the mediators indicated at 2 h and 24 h in media alone (light grey bars and dark grey bars, respectively) or with <i>Listeria</i> (open bars and black bars, respectively). Undetectable levels are indicated (ND). Data are mean +/- SEM for 4 independent experiments.</p