Cell-Type Specific Changes in Glial Morphology and Glucocorticoid Expression During Stress and Aging in the Medial Prefrontal Cortex.

Repeated exposure to stressors is known to produce large-scale remodeling of neurons within the prefrontal cortex (PFC). Recent work suggests stress-related forms of structural plasticity can interact with aging to drive distinct patterns of pyramidal cell morphological changes. However, little is known about how other cellular components within PFC might be affected by these challenges. Here, we examined the effects of stress exposure and aging on medial prefrontal cortical glial subpopulations. Interestingly, we found no changes in glial morphology with stress exposure but a profound morphological change with aging. Furthermore, we found an upregulation of non-nuclear glucocorticoid receptors (GR) with aging, while nuclear levels remained largely unaffected. Both changes are selective for microglia, with no stress or aging effect found in astrocytes. Lastly, we show that the changes found within microglia inversely correlated with the density of dendritic spines on layer III pyramidal cells. These findings suggest microglia play a selective role in synaptic health within the aging brain

Galanin-expressing GABA neurons in the lateral hypothalamus modulate food reward and noncompulsive locomotion

© 2017 the authors. The lateral hypothalamus (LHA) integrates reward and appetitive behavior and is composed of many overlapping neuronal populations. Recent studies associated LHA GABAergic neurons (LHAGABA), which densely innervate the ventral tegmental area (VTA), with modulation of food reward and consumption; yet, LHAGABA projections to the VTA exclusively modulated food consumption, not reward. We identified a subpopulation of LHA GABA neurons that coexpress the neuropeptide galanin (LHAGal). TheseLHAGal neurons also modulate food reward, but lack direct VTA innervation. We hypothesized that LHAGal neurons may represent a subpopulation of LHAGABA neurons that mediates food reward independent of direct VTA innervation. We used chemogenetic activation of LHAGal or LHAGABA neurons in mice to compare their role in feeding behavior. We further analyzed locomotor behavior to understand how differentia lVTA connectivity and transmitter release in these LHA neurons influences this behavior. LHAGal or LHAGABA neuronal activation both increased operant food-seeking behavior, but only activation of LHAGABA neurons increased overall chow consumption. Additionally, LHAGal or LHAGABA neuronal activation similarly induced locomotor activity, but with striking differences in modality. Activation of LHAGABA neurons induced compulsive-like locomotor behavior; while LHAGal neurons induced locomotor activity without compulsivity. Thus, LHAGal neurons define a subpopulation of LHAGABA neurons without direct VTA innervation that mediate non compulsive food-seeking behavior. We speculate that the striking difference in compulsive-like locomotor behavior is also based on differential VTA innervation. The downstream neural network responsible for this behavior and a potential role for galanin as neuromodulator remains to be identified

Site-Selective Excitation And Polarized Absorption Spectra Of Nd3+ In Sr-5(Po4)(3)F And Ca-5(Po4)(3)F

Polarized absorption and fluorescence spectra were analyzed to establish individual energy (Stark) levels of Nd3+ ions in host crystals of Sr-5(PO4)(3)F (SFAP) and Ca-5(PO4)(3)F (FAP). Site-selective excitation and fluorescence facilitated differentiation between Nd3+ ions in emitting sites-associated with 1.06 mu m stimulated emission, and nonemitting Nd3+ ions in other sites. Measurements were made on samples containing different concentrations of Nd3+ at 4 K and higher temperatures. Substitution of Nd3+ for Sr2+ or Ca2+ was accompanied by passive charge compensation during crystal growth. Crystal-field splitting calculations were performed according to site for Stark levels of Nd3+ ions identified spectroscopically. We obtained a final set of crystal-field parameters B-nm for Nd3+ ions in fluorescing sites with a rms, deviation of 7 cm(-1) (52 levels in Nd:SFAP) and 8 cm(-1) (59 levels in Nd:FAP). For one of the nonemitting sites in Nd:FAP we obtained a final set of B-nm parameters which gave a rms deviation of 6 cm(-1) between 46 experimental and calculated levels

An AMPKa2-specific phospho-switch controls lysosomal targeting for activation

AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin complex 1 (mTORC1) are metabolic kinases that co-ordinate nutrient supply with cell growth. AMPK negatively regulates mTORC1, and mTORC1 reciprocally phosphorylates S345/7 in both AMPK α-isoforms. We report that genetic or torin1-induced loss of α2-S345 phosphorylation relieves suppression of AMPK signaling; however, the regulatory effect does not translate to α1-S347 in HEK293T or MEF cells. Dephosphorylation of α2-S345, but not α1-S347, transiently targets AMPK to lysosomes, a cellular site for activation by LKB1. By mass spectrometry, we find that α2-S345 is basally phosphorylated at 2.5-fold higher stoichiometry than α1-S347 in HEK293T cells and, unlike α1, phosphorylation is partially retained after prolonged mTORC1 inhibition. Loss of α2-S345 phosphorylation in endogenous AMPK fails to sustain growth of MEFs under amino acid starvation conditions. These findings uncover an α2-specific mechanism by which AMPK can be activated at lysosomes in the absence of changes in cellular energy

Estradiol and mTORC2 cooperate to enhance prostaglandin biosynthesis and tumorigenesis in TSC2-deficient LAM cells

Lymphangioleiomyomatosis (LAM) is a progressive neoplastic disorder that leads to lung destruction and respiratory failure primarily in women. LAM is typically caused by tuberous sclerosis complex 2 (TSC2) mutations resulting in mTORC1 activation in proliferative smooth muscle–like cells in the lung. The female predominance of LAM suggests that estradiol contributes to disease development. Metabolomic profiling identified an estradiol-enhanced prostaglandin biosynthesis signature in Tsc2-deficient (TSC−) cells, both in vitro and in vivo. Estradiol increased the expression of cyclooxygenase-2 (COX-2), a rate-limiting enzyme in prostaglandin biosynthesis, which was also increased at baseline in TSC-deficient cells and was not affected by rapamycin treatment. However, both Torin 1 treatment and Rictor knockdown led to reduced COX-2 expression and phospho-Akt-S473. Prostaglandin production was also increased in TSC-deficient cells. In preclinical models, both Celecoxib and aspirin reduced tumor development. LAM patients had significantly higher serum prostaglandin levels than healthy women. 15-epi-lipoxin-A4 was identified in exhaled breath condensate from LAM subjects and was increased by aspirin treatment, indicative of functional COX-2 expression in the LAM airway. In vitro, 15-epi-lipoxin-A4 reduced the proliferation of LAM patient–derived cells in a dose-dependent manner. Targeting COX-2 and prostaglandin pathways may have therapeutic value in LAM and TSC-related diseases, and possibly in other conditions associated with mTOR hyperactivation

Site-selective excitation and polarized absorption and emission spectra of trivalent thulium and erbium in strontium fluorapatite

Polarized fluorescence spectra produced by site-selective excitation, and conventional polarized absorption spectra were obtained for Tm3+ and Er3+ ions individually incorporated into single crystals of strontium fluorapatite, Sr-5(PO4)(3)F, also known as SFAP. Substitution of the trivalent rare earth ion for divalent strontium was achieved by passive charge compensation during Czochralski growth of the fluorapatite crystals. Spectra were obtained between 1780 and 345 nm at temperatures from 4 K to room temperature on crystals having the hexagonal structure [P6(3)/m(C-6h(2))]. The polarized fluorescence spectra due to transitions from multiplet manifolds of Tm3+(4f(12)), including D-1(2), (1)G(4), and H-3(4) to manifolds H-3(6) (the ground-state manifold), F-3(4), H-3(5), H-3(4), and F-3(3) were analyzed for the details of the crystal-field splitting of the manifolds. Fluorescence Lifetimes were measured for Tm3+ transitions from D-1(2), (1)G(4), and H-3(4) at room temperature and from (1)G(4) at 16 K. Results of the analysis indicate that the majority of Tm3+ ions occupy sites having C-s symmetry. A point-charge lattice-sum calculation was made in which the crystal-field components, A(nm), were determined assuming that trivalent thulium replaces divalent strontium in the metal site having C-s symmetry. Results support the conclusion that the nearest-neighbor fluoride (F-) is replaced by divalent oxygen (O2-), thus preserving overall charge neutrality and local symmetry. Crystal-field splitting calculations predict energy levels in agreement with results obtained from an analysis of the experimental data. By varying the crystal-field parameters, B-nm, we obtained a rms difference of 7 cm(-1) between 43 calculated and experimental Stark levels for Tm3+(4f(12)) in Tm:SFAP. Absorption and fluorescence spectra are also reported for Er3+ ions in Er:SFAP. Measurement of the temporal decay of the room temperature fluorescence from the I-4(11/2) and I-4(13/2) manifolds yielded fluorescence lifetimes of 230+/-20 mu s and 8.9+/-0.1 ms, respectively. The experimental Stark levels obtained from an analysis of the spectroscopic data were compared with a crystal-field splitting calculation. The initial set of B-nm parameters for Er3+(4f(11)) was established from the three-parameter theory and the final set of B-nm parameters obtained for Tm3+(4f(12)) in Tm:SFAP. The best overall agreement between calculated and experimental Stark levels is 8 cm(-1) for 48 Stark levels, representing 12 observed multiplet manifolds of Er3+(4f(11)) in Er:SFAP

Placental vascularity and markers of angiogenesis in relation to prenatal growth status in overnourished adolescent ewes.

INTRODUCTION: Placental vascularity may be important in the development of fetal growth restriction (FGR). The overnourished adolescent ewe is a robust model of the condition, with ∼50% of offspring demonstrating FGR (birthweight >2 standard deviations below optimally-fed control mean). We studied whether placental vascularity, angiogenesis and glucose transport reflect FGR severity. METHODS: Singleton pregnancies were established in adolescent ewes either overnourished to putatively restrict fetoplacental growth (n = 27) or control-fed (n = 12). At 131d (term = 145d) pregnancies were interrupted and fetuses classified as FGR (n = 17,  Non-FGR > FGR and fetal:placental weight ratios were higher in overnourished versus Control groups. COT vascular indices were Non-FGR > FGR > Control. COT-CAD, CSD and APC were significantly greater in Non-FGR overnourished versus Control and intermediate in FGR groups. CAR vascularity did not differ. CAR-VEGFA/FLT1/KDR/ANGPT1/ANGPT2/SLC2A1/SLC2A3 mRNA was lower and COT-ANGPT2 higher in overnourished versus Control groups. DISCUSSION: Relative to control-intake pregnancy, overnourished pregnancies are characterised by higher COT vascularity, potentially a compensatory response to reduced nutrient supply, reflected by higher fetal:placental weight ratios. Compared with overnourished pregnancies where fetal growth is relatively preserved, overnourished pregnancies culminating in marked FGR have less placental vascularity, suggesting incomplete adaptation to the prenatal insult