62 research outputs found
Observation of nuclei with energies 8-30 MeV per nucleon in the Earth's magnetosphere at the altitudes 350 KM
Observations of the flux of nuclei with an energy of IO MeV per nucleon on the Salyut-7 Station in September 1984 are presented. The observed flux is smaller by a factor of 50 than the flux detected in May, 1981
Urine-derived cells for human cell therapy
Corrected by: Correction to: Urine-derived cells for human cell therapy (Stem Cell Res Ther. (2018) 9 (189) DOI: 10.1186/s13287-018-0932-z). The original article [1] contained a small typo affecting the co-author, Mohammed Al-Hawwas's name. This error has now been corrected.Desirable cells for human cell therapy would be ones that can be generated by simple isolation and culture techniques using a donor sample obtained by non-invasive methods. To date, the different donor-specific cells that can be isolated from blood, skin, and hair require invasive methods for sample isolation and incorporate complex and costly reagents to culture. These cells also take considerable time for their in-vitro isolation and expansion. Previous studies suggest that donor-derived cells, namely urine stem cells and renal cells, may be isolated from human urine samples using a cost-effective and simple method of isolation, incorporating not such complex reagents. Moreover, the isolated cells, particularly urine stem cells, are superior to conventional stem cell sources in terms of favourable gene profile and inherent multipotent potential. Transdifferentiation or differentiation of human urine-derived cells can generate desirable cells for regenerative therapy. In this review, we intended to discuss the characteristics and therapeutic applications of urine-derived cells for human cell therapy. Conclusively, with detailed study and optimisation, urine-derived cells have a prospective future to generate functional lineage-specific cells for patients from a clinical translation point of view.Nimshitha Pavathuparambil Abdul Manaph, Mohammed Al-Hawwas, Larisa Bobrovskaya, Patrick T. Coates and Xin-Fu Zho
Knockout of p75 neurotrophin receptor attenuates the hyperphosphorylation of Tau in pR5 mouse model
p75 neurotrophin receptor (p75NTR) has been implicated in Alzheimer's disease (AD). However, whether p75NTR is involved in Tau hyperphosphorylation, one of the pathologies observed in AD, remains unclear. In our previous study, the extracellular domain of p75NTR blocked amyloid beta (Aβ) toxicity and attenuated Aβ-induced Tau hyperphosphorylation. Here we show that, in the absence of Aβ, p75NTR regulates Tau phosphorylation in the transgenic mice with the P301L human Tau mutation (pR5). The knockout of p75NTR in pR5 mice attenuated the phosphorylation of human Tau. In addition, the elevated activity of kinases responsible for Tau phosphorylation including glycogen synthase kinase 3 beta; cyclin-dependent-kinase 5; and Rho-associated protein kinase was also inhibited when p75NTR is knocked out in pR5 mice at 9 months of age. The increased caspase-3 activity observed in pR5 mice was also abolished in the absence of p75NTR. Our study also showed that p75NTR is required for Aβ- and pro-brain derived neurotrophin factor (proBDNF)-induced Tau phosphorylation, in vitro. Overall, our data indicate that p75NTR is required for Tau phosphorylation, a key event in the formation of neurofibrillary tangles, another hallmark of AD. Thus, targeting p75NTR could reduce or prevent the pathologic hyperphosphorylation of Tau.Noralyn B. Mañucat-Tan, Lin-Lin Shen, Larisa Bobrovskaya, Mohammed Al-hawwas, Fiona H. Zhou, Yan-Jiang Wang, Xin-Fu Zho
Codeine-induced hyperalgesia and allodynia: investigating the role of glial activation
Chronic morphine therapy has been associated with paradoxically increased pain. Codeine is a widely used opioid, which is metabolized to morphine to elicit analgesia. Prolonged morphine exposure exacerbates pain by activating the innate immune toll-like receptor-4 (TLR4) in the central nervous system. In silico docking simulations indicate codeine also docks to MD2, an accessory protein for TLR4, suggesting potential to induce TLR4-dependent pain facilitation. We hypothesized codeine would cause TLR4-dependent hyperalgesia/allodynia that is disparate from its opioid receptor-dependent analgesic rank potency. Hyperalgesia and allodynia were assessed using hotplate and von Frey tests at days 0, 3 and 5 in mice receiving intraperitoneal equimolar codeine (21 mg kg(-1)), morphine (20 mg kg(-1)) or saline, twice daily. This experiment was repeated in animals with prior partial nerve injury and in TLR4 null mutant mice. Interventions with interleukin-1 receptor antagonist (IL-1RA) and glial-attenuating drug ibudilast were assessed. Analyses of glial activation markers (glial fibrillary acid protein and CD11b) in neuronal tissue were conducted at the completion of behavioural testing. Despite providing less acute analgesia (P=0.006), codeine induced similar hotplate hyperalgesia to equimolar morphine vs saline (-9.5 s, P<0.01 and -7.3 s, P<0.01, respectively), suggesting codeine does not rely upon conversion to morphine to increase pain sensitivity. This highlights the potential non-opioid receptor-dependent nature of codeine-enhanced pain sensitivity-although the involvement of other codeine metabolites cannot be ruled out. IL-1RA reversed codeine-induced hyperalgesia (P<0.001) and allodynia (P<0.001), and TLR4 knock-out protected against codeine-induced changes in pain sensitivity. Glial attenuation with ibudilast reversed codeine-induced allodynia (P<0.001), and thus could be investigated further as potential treatment for codeine-induced pain enhancement.J L Johnson, P E Rolan, M E Johnson, L Bobrovskaya, D B Williams, K Johnson, J Tuke, and M R Hutchinso
Low birth weight activates the renin-angiotensin system, but limits cardiac angiogenesis in early postnatal life
Low birth weight (LBW) is associated with increased risk of adult cardiovascular disease and this association may be partly a consequence of early programming of the renin-angiotensin system (RAS). We investigated the effects of LBW on expression of molecules in the RAS and cardiac tissue remodeling. Left ventricular samples were collected from the hearts of 21 days old lambs that were born average birth weight (ABW) and LBW. Cardiac mRNA expression was quantified using real-time RT-PCR and protein expression was quantified using Western blotting. DNA methylation and histone acetylation were assessed by combined bisulfite restriction analysis and chromatin immunoprecipitation, respectively. There were increased plasma renin activity, angiotensin I (ANGI), and ANGII concentrations in LBW compared to ABW lambs at day 20. In LBW lambs, there was increased expression of cardiac ACE2 mRNA, decreased ANGII receptor type 1 (AT1R) protein, and acetylation of histone H3K9 of the AT1R promoter but no changes in AT1R mRNA expression and AT1R promoter DNA methylation. There was no difference in the abundance of proteins involved in autophagy or fibrosis. BIRC5 and VEGF mRNA expression was increased; however, the total length of the capillaries was decreased in the hearts of LBW lambs. Activation of the circulating and local cardiac RAS in neonatal LBW lambs may be expected to increase cardiac fibrosis, autophagy, and capillary length. However, we observed only a decrease in total capillary length, suggesting a dysregulation of the RAS in the heart of LBW lambs and this may have significant implications for heart health in later life.Kimberley C. W. Wang, Doug A. Brooks, Brooke Summers‐Pearce, Larisa Bobrovskaya, Darran N. Tosh, Jaime A. Duffield, Kimberley J. Botting, Song Zhang, I. Caroline McMillen, Janna L. Morriso
Dichotomy of Tyrosine Hydroxylase and Dopamine Regulation between Somatodendritic and Terminal Field Areas of Nigrostriatal and Mesoaccumbens Pathways
Measures of dopamine-regulating proteins in somatodendritic regions are often used only as static indicators of neuron viability, overlooking the possible impact of somatodendritic dopamine (DA) signaling on behavior and the potential autonomy of DA regulation between somatodendritic and terminal field compartments. DA reuptake capacity is less in somatodendritic regions, possibly placing a greater burden on de novo DA biosynthesis within this compartment to maintain DA signaling. Therefore, regulation of tyrosine hydroxylase (TH) activity may be particularly critical for somatodendritic DA signaling. Phosphorylation of TH at ser31 or ser40 can increase activity, but their impact on L-DOPA biosynthesis in vivo is unknown. Thus, determining their relationship with L-DOPA tissue content could reveal a mechanism by which DA signaling is normally maintained. In Brown-Norway Fischer 344 F1 hybrid rats, we quantified TH phosphorylation versus L-DOPA accumulation. After inhibition of aromatic acid decarboxylase, L-DOPA tissue content per recovered TH protein was greatest in NAc, matched by differences in ser31, but not ser40, phosphorylation. The L-DOPA per catecholamine and DA turnover ratios were significantly greater in SN and VTA, suggesting greater reliance on de novo DA biosynthesis therein. These compartmental differences reflected an overall autonomy of DA regulation, as seen by decreased DA content in SN and VTA, but not in striatum or NAc, following short-term DA biosynthesis inhibition from local infusion of the TH inhibitor α-methyl-p-tyrosine, as well as in the long-term process of aging. Such data suggest ser31 phosphorylation plays a significant role in regulating TH activity in vivo, particularly in somatodendritic regions, which may have a greater reliance on de novo DA biosynthesis. Thus, to the extent that somatodendritic DA release affects behavior, TH regulation in the midbrain may be critical for DA bioavailability to influence behavior
PKA regulatory subunits mediate synergy among conserved G-protein-coupled receptor cascades
G-protein-coupled receptors sense extracellular chemical or physical stimuli and transmit these signals to distinct trimeric G-proteins. Activated Gα-proteins route signals to interconnected effector cascades, thus regulating thresholds, amplitudes and durations of signalling. Gαs- or Gαi-coupled receptor cascades are mechanistically conserved and mediate many sensory processes, including synaptic transmission, cell proliferation and chemotaxis. Here we show that a central, conserved component of Gαs-coupled receptor cascades, the regulatory subunit type-II (RII) of protein kinase A undergoes adenosine 3′-5′-cyclic monophosphate (cAMP)-dependent binding to Gαi. Stimulation of a mammalian Gαi-coupled receptor and concomitant cAMP-RII binding to Gαi, augments the sensitivity, amplitude and duration of Gαi:βγ activity and downstream mitogen-activated protein kinase signalling, independent of protein kinase A kinase activity. The mechanism is conserved in budding yeast, causing nutrient-dependent modulation of a pheromone response. These findings suggest a direct mechanism by which coincident activation of Gαs-coupled receptors controls the precision of adaptive responses of activated Gαi-coupled receptor cascades
Effects of corticosterone on BDNF expression and mood behaviours in mice
Stress hormones such as cortisol play a critical role in depressive disorders. Therefore, corticosterone has been used to develop a depression model in animals. Our previous studies found that the precursor of brain-derived neurotrophic factor (proBDNF) and its receptors are upregulated in depression in human and animal models. In the present study, we aimed to examine whether proBDNF and mature BDNF (mBDNF) are altered in the corticosterone-induced depression model in mice. Male and female mice were given corticosterone dissolved in 0.3% hydroxypropyl- β-cyclodextrin (β-CD) or vehicle (β-CD) in drinking water for 33 days. We have found that corticosterone induced depressive-like behaviours as reflected by increased immobility time in the tail suspen- sion test and decreased grooming time in the splash test. Corticosterone also induced anxiety-like behaviours as represented by decreased entries into the central zone of the open field test and the open arms of the elevated plus maze test. We found that corticosterone administration resulted in differential changes of proBDNF and mature BDNF in different brain regions and peripheral tissues. ProBDNF was increased in the hippocampus and cerebellum, but no change was found in the prefrontal cortex and hypothalamus. Both proBDNF and mBDNF were significantly increased in the pituitary gland. In contrast, proBDNF was significantly decreased in the ad- renal gland. There were no significant changes in proBDNF or mBDNF in other peripheral tissues, including the liver and sex organs. We conclude that the stress hormone corticosterone causes depressive behaviours but differentially regulates the processing of proBDNF in mice. ProBDNF may participate in the development of depression behaviours in corticosterone treated animals.Liying Lin, Mauritz Frederick Herselman, Xin-Fu Zhou, Larisa Bobrovskay
Preclinical validation of a novel oral Edaravone formulation for treatment of frontotemporal dementia
Oxidative stress is a key factor in the pathogenesis of several neurodegenerative disorders and is involved in the accumulation of amyloid beta plaques and Tau inclusions. Edaravone (EDR) is a free radical scavenger that is approved for motor neuron disease and acute ischemic stroke. EDR alleviates pathologies and cognitive impairment of AD via targeting multiple key pathways in transgenic mice. Herein, we aimed to study the effect of EDR on Tau pathology in P301L mice; an animal model of frontotemporal dementia (FTD), at two age time points representing the early and late stages of the disease. A novel EDR formulation was utilized in the study and the drug was delivered orally in drinking water for 3 months. Then, behavioral tests were conducted followed by animal sacrifice and brain dissection. Treatment with EDR improved the reference memory and accuracy in the probe trial as evaluated in Morris water maze, as well as novel object recognition and significantly alleviated motor deficits in these mice. EDR also reduced the levels of 4-hydroxy-2-nonenal and 3-nitrotyrosine adducts. In addition, immunohistochemistry showed that EDR reduced tau phosphorylation and neuroinflammation and partially rescued neurons against oxidative neurotoxicity. Moreover, EDR attenuated downstream pathologies involved in Tau hyperphosphorylation. These results suggest that EDR may be a potential therapeutic agent for the treatment of FTD.Sally Kelliny, Jing Xiong, Larisa Bobrovskaya and Xin-Fu Zho
Female rats display fewer optimistic responses in a judgment bias test in the absence of a physiological stress response
Metabolic cages are a type of housing used in biomedical research. Metabolic cage housing has been demonstrated to elicit behavioural and physiological changes in rodents housed within them. The nature of this effect has been characterized as anxiogenic. However, few studies have evaluated positive affect in response to metabolic cage housing and the interaction between this, sex and traditional physiological measures of stress. Cognitive biasing, as measured through a judgment bias paradigm has proven a reliable measure of animal affective state, particularly through its ability to measure positive affect. The current study investigated differences in cognitive biasing between male and female rats when transferred from open-top, grouped housing to a metabolic cage. Rats (Rattus norvegicus) (n = 60) were trained in a judgment bias paradigm previously validated for use in the rat model. Upon exposure to an intermediate, ambiguous probe rats responded with either an optimistic or pessimistic decision. The animals were also subjected to the sucrose preference test to identify the presence of anhedonia. Faecal corticosterone and changes in adrenal tyrosine hydroxylase were also measured to establish whether a stress-like state was experienced. There was a significant interaction between sex and metabolic cage housing on the number of optimistic decisions made F (1, 56)=7.461, p=0.008. Female rats that remained in control housing responded with a reduced number of days featuring an optimistic decision compared to males in control housing (p=0.036). However, both males and females responded with significantly fewer optimistic decisions in the metabolic cage compared to control (p b 0.001). There was a significant negative correlation between treatment and sucrose consumption (rpb=−0.654, n=195, p b 0.001). There was also a significant sex effect for faecal corticosterone concentrations F (1, 30) = 6.305, p = 0.018) with female rats (4.050 ± 1.285), displaying greater corticosterone concentrations than males (2.291±0.495). No differences between treatment were observed for either corticosterone or tyrosine hydroxylase levels. This data demonstrates that movement into a metabolic cage resulted in rats displaying significantly greater pessimistic cognitive biases as determined through the judgment bias test. Interestingly, male rats that remained in control housing demonstrated cognitive biases that were not equivalent to female rats. Furthermore, despite a behavioural change being evident, a physiological change in corticosterone or tyrosine hydroxylase levels was not observed.T.H. Barker, L. Bobrovskaya, G.S. Howarth, A.L.Whittake
- …