Neurochemistry

Protective effect of a 3 kDa peptide obtained from beef myofibrillar protein using alkaline-AK on neuronal cells Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): Seung Yun Lee, Sun Jin Hur Abstract The protective effect of two 3 kDa peptide fractions (AK3KF1 and AK3KF2), obtained from beef myofibrillar protein using an inexpensive enzyme (alkaline-AK) on human neuronal cells (SH-SY5Y) against H2O2-induced apoptosis was investigated. These peptides were isolated and further separated by fast protein liquid chromatography (FPLC), and their protective effect against H2O2-mediated cell death was measured by determining cell viability, nitric oxide (NO) production, mitochondrial membrane potential (MMP), apoptosis, morphological changes in cell nuclei, and in vitro antioxidant assays. The results indicated that treatment with peptide fractions increased cell viability and MMP, and decreased NO production, fragmentation of cell nuclei, and apoptosis in H2O2-treated SH-SY5Y cells. This is the first study to report neuroprotective effects of a peptide obtained from beef myofibrillar protein. The peptide sequence was identified as Thr-Gln-Lys-Lys-Val-Ile-Phe-Cys (TQKKVIFC). Thus, these findings suggest that TQKKVIFC can prevent neuronal cell death and could be useful in preventing neurodegenerative diseases. Graphical abstract

Repeated exposure to methiopropamine increases dendritic spine density in the rat nucleus accumbens core Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): Wen Ting Cai, Hyung Shin Yoon, Sooyeun Lee, Jeong-Hoon Kim Abstract Repeated exposure to classical psychomotor stimulants, like amphetamine (AMPH), produces locomotor sensitization and accompanied structural plasticity of dendritic spines in the nucleus accumbens (NAcc). Following our previous report that repeated administration of methiopropamine (MPA), a structural analog to meth-AMPH, produces locomotor sensitization, it was examined in the present study whether this behavioral change also accompanies with structural plasticity in the NAcc in a similar way to AMPH. A week after adeno-associated viral vectors containing enhanced green fluorescent protein (eGFP) were microinjected into the NAcc core, rats were repeatedly injected with saline, AMPH (1 mg/kg, IP), or MPA (5 mg/kg, IP) once every 2–3 days for a total of 4 times. Two weeks after last injection, all rats were perfused and their brains were processed for immunohistochemical staining. The image stacks for dendrite segments of medium spiny neuronal cells in the NAcc core were obtained and dendritic spines were quantitatively analyzed. Interestingly, it was found that the number of total spine density, with thin spine as a major contributor, was significantly increased in MPA compared to saline pre-exposed group, in a similar way to AMPH. These results indicate that MPA, a novel psychoactive substance, has similar characteristics with AMPH in that they both produce structural as well as behavioral changes, further supporting MPA's dependence and abuse potential.

Ammonium induced dysfunction of 5-HT2B receptor in astrocytes Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): Tingting Yue, Baoman Li, Li Gu, Jingyang Huang, Alexei Verkhratsky, Liang Peng Abstract Previously we reported that gene expression of astrocytic 5-HT2B receptors was decreased in brains of depressed animals exposed to chronic mild stress (CMS) (Li et al., 2012) and of Parkinson's disease (Song et al., 2018). Depression is also one of the psychiatric symptoms in hyperammonemia, and astrocyte is a primary target of ammonium in brain in vivo. In the present study, we have used preparations of the brains of urease-treated mice and ammonium-treated astrocytes in culture to study gene expression and function of 5-HT2B receptors. The urease-treated mice showed depressive behaviour. Both mRNA and protein of 5-HT2B receptors were increased in the brains of urease-treated mice and in ammonium-treated cultured astrocytes. Further study revealed that mRNA and protein expression of adenosine deaminase acting on RNA 2 (ADAR2), an enzyme catalyze RNA deamination of adenosine to inosine was increased in the brains of urease-treated mice and in ammonium-treated cultured astrocytes. This increase in ADAR2 induced RNA editing of 5-HT2B receptors. Cultured astrocytes treated with ammonium lost 5-HT induced Ca2+ signalling and ERK1/2 phosphorylation, indicating dysfunction of 5-HT2B receptors. This is in agreement with our previous observation that edited 5-HT2Breceptors no longer respond to 5-HT (Hertz et al., 2014). Ammonium effects are inhibited by ADAR2 siRNA in cultured astrocytes, suggesting that increased gene expression and editing and loss of function of 5-HT2Breceptors are results of increased activity of ADAR2. In summary, we have demonstrated that functional malfunction of astrocytic 5-HT2B receptors occurs in animal models of major depression, Parkinson depression and hepatic encephalopathy albeit via different mechanisms. Understanding the role of astrocytic 5-HT2B receptors in different pathological contexts may instigate development of novel therapeutic strategies for treating disease-specific depressive behaviour.

Tat-HSP70 protects neurons from oxidative damage in the NSC34 cells and ischemic damage in the ventral horn of rabbit spinal cord Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): Woosuk Kim, Hyun Jung Kwon, Hyo Young Jung, Dae Young Yoo, Seung Myung Moon, Dae Won Kim, In Koo Hwang Abstract Heat shock protein 70 (HSP70) is an ATP-dependent molecular chaperone, and it has been shown that its levels increase after exposure to various types of stress, including ischemia. In the present study, we investigated the effects of HSP70 against H2O2-induced neuronal stress in NSC34 cells and against spinal cord ischemia in rabbits. Tat-HSP70 proteins facilitated the intracellular delivery of HSP70 into the NSC34 cells and enabled them to cross the blood-brain barrier in the rabbit spinal cord. Tat-HSP70 was effectively transduced into NSC34 cells in a concentration- and time-dependent manner, while control-HSP70 protein could not be delivered intracellularly at any concentration or time after treatment. Treatment with Tat-HSP70 reduced the generation of reactive oxygen species and cell death induced by H2O2, while the control-HSP70 did not show any significant effect on the NSC34 cells exposed to H2O2. In rabbit spinal cord, the administration of Tat-HSP70 showed significant amelioration of neurological defects and neuronal death in the ventral horn of spinal cord. In addition, Tat-HSP70 treatment significantly reduced lipid peroxidation and increased Cu, Zn-superoxide dismutase activities in the spinal cord, but glutathione peroxidase and Mn-superoxide dismutase activities remained unchanged. These results suggest that Tat-HSP70, not control-HSP70, decreases cell damage by reducing oxidative stress in NSC34 cells and rabbit spinal cord, and it can be employed for the reduction of neuronal damage caused after spinal cord ischemia.

Gut dysbiosis and lack of short chain fatty acids in a Chinese cohort of patients with multiple sclerosis Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): Qin Zeng, Junli Gong, Xiyuan Liu, Chen Chen, Xiaobo Sun, Huijuan Li, Yifan Zhou, ChunPing Cui, Yuge Wang, Yu Yang, Aimin Wu, Yaqing Shu, Xueqiang Hu, Zhengqi Lu, Song Guo Zheng, Wei Qiu, Yongjun Lu Abstract Background Recent studies, mostly conducted in Western countries, showed that gut microbes are involved in the pathogenesis of multiple sclerosis (MS). Objective The aim of this study was to investigate whether gut dysbiosis is relevant to the initiation and progression of MS in a Chinese population. Methods Next-generation sequencing (NGS) and gas chromatography (GC) were integrated and used to compare the fecal bacterial communities and the short-chain fatty acid (SCFA) levels among relapsing-remitting MS (RRMS) patients (n = 34), neuromyelitis optica spectrum disorder (NMOSD) patients (n = 34), and healthy controls (HCs) (n = 34). T-cell profile analyses were performed by flow cytometry for MS patients and matched controls (n = 12). Results (1) The gut microbiome of MS patients was characterized by an increase of Streptococcus and a decrease of Prevotella_9; additionally, compared to NMOSD patients, Prevotella_9 was found to be much more abundant in MS patients. (2) A striking depletion of fecal acetate, propionate, and butyrate was observed in MS patients compared to HCs. (3) The abundance of Streptococcus was negatively correlated with the proportion of pTregs (P < 0.05) and positively correlated with Th17 cells (P < 0.05) in the peripheral blood, while the abundance of Prevotella_9 was negatively correlated with the Th17 cell frequency (P < 0.01), and the fecal SCFA level was positively correlated with pTreg frequency (P < 0.05). Conclusions Gut dysbiosis and a lack of SCFAs exist in Chinese MS patients, which might be related to an aberrant immune response of MS; this relationship may have a diagnostic and therapeutic value for patients with MS.

ML171, a specific inhibitor of NOX1 attenuates formalin induced nociceptive sensitization by inhibition of ROS mediated ERK1/2 signaling Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): Sanjay Kumar, Ajeet Kumar Singh, Manjula Vinayak Abstract Reactive oxygen species (ROS) have a key role in different etiologies of pain. At sub-cellular level, mitochondria and plasma membranes have been identified as endogenous sources of ROS required for pain generation. NADPH oxidase (NOX) is the main contributor of membrane associated ROS generation. Out of 7 isozymes, NOX1, NOX2 and NOX4 are reported to be associated with nociceptive sensitization. Therefore, it has been hypothesized that specific inhibition of the NOX isozymes could be putative strategy for treatment of pain. However, unavailability of specific inhibitors was the biggest obstacle to test this hypothesis. Here, we investigated anti-nociceptive potential of a newly identified specific NOX1 inhibitor ML171 in formalin induced inflammatory pain. ML171 administration decreased the paw lickings and flinching response in both phases of formalin test. Behavioral response was supported with decreased activation of c-Fos in spinal dorsal horn. The increased level of total NOX activity, ROS and pERK1/2 in dorsal root ganglion (DRG) and spinal dorsal horn of formalin induced nociception were reversed by ML171 administration. ML171 also inhibited the upregulated Tumor necrosis factor receptor 1 (TNFR1) expression in DRG, whereas did not show any effect in spinal dorsal horn which was unaltered after formalin insult. The study for the first time depicts anti-nociceptive potential of ML171 via regulation of ROS mediated ERK1/2 signaling by inhibition of NOX1 activity.

Behavioral alterations induced by post-weaning isolation rearing of rats are accompanied by reduced VGF/BDNF/TrkB signaling in the hippocampus Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): M. Chmelova, L. Balagova, M. Marko, S. Vrankova, M. Cebova, D. Jezova, I. Riecansky, N. Hlavacova Abstract Post-weaning social isolation has been shown to be a relevant animal model for studying the mechanisms underlying psychopathological states induced by early-life stressful experiences. Besides extensively studied brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) receptor, increasing attention is being given to a neuropeptide precursor VGF (non-acronymic). Several lines of evidence indicate an interplay between the neurotrophins and nitric oxide signaling. This study investigated the long-term consequences of post-weaning social isolation on behavior, VGF/BDNF/TrkB pathway and two isoforms of nitric oxide synthase (NOS) in the hippocampus and examined whether these effects were sex-specific. Male and female Sprague-Dawley rats were reared either in social isolation or social groups from postnatal day 21 for 9 weeks (n = 12–15/group and sex). Post-weaning social isolation induced impairments in sensorimotor gating and increased anxiety-like behavior in rats of both sexes. These behavioral alterations were accompanied by attenuated gene expression of VGF and TrkB receptor in the hippocampus. Isolation-induced reduction in VGF gene expression was more evident in male isolates. Similar changes were found in neuronal NOS (nNOS) gene expression with reduced mRNA levels in male isolates. Gene expression of BDNF and inducible NOS was not influenced by isolation rearing or sex. In addition, sex-specific patterns of VGF and nNOS gene expression in the hippocampus with higher mRNA levels in males than in females were revealed. The present study demonstrates a relationship between nNOS, VGF, BDNF, and TrkB confirming a link between nitric oxide and neurotrophins signaling pathways. Our findings indicate that long-term post-weaning social isolation alters signaling via VGF/BDNF/TrkB and nNOS that could interfere with neurodevelopmental processes which may contribute to pathological behavioral symptoms in adulthood. Future studies are needed to support this suggestion since the direct mechanistic link has not been approached in this study. Graphical abstract

Acute lysine overload provokes marked striatum injury involving oxidative stress signaling pathways in glutaryl-CoA dehydrogenase deficient mice Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): Alexandre Umpierrez Amaral, Bianca Seminotti, Janaína Camacho da Silva, Francine Hehn de Oliveira, Rafael Teixeira Ribeiro, Guilhian Leipnitz, Diogo Onofre Souza, Moacir Wajner Abstract Glutaric acidemia type I (GA I) is a neurometabolic disorder of lysine (Lys) catabolism caused by glutaryl-CoA dehydrogenase (GCDH) deficiency. Patients are susceptible to develop acute striatum degeneration during catabolic stress situations whose underlying mechanisms are not fully established. Thus, in the present work we investigated the effects of a single intrastriatal Lys administration (1.5–4 μmol) to 30-day-old wild type (WT) and GCDH deficient (Gcdh−/−) mice on brain morphology, neuronal injury, astrocyte reactivity and myelin structure, as well as signaling pathways of redox homeostasis. We observed a marked vacuolation/edema in striatum and at higher doses also in cerebral cortex of Gcdh−/−, but not of WT mice. Lys also provoked a reduction of NeuN and synaptophysin, as well as an increase of astrocytic GFAP, in the striatum of Gcdh−/− mice, indicating neuronal loss and astrocyte reactivity. Furthermore, we verified an increase of Nrf2 and NF-κB expression in the nuclear fraction, and a decrease of heme oxygenase-1 (HO-1) content in the striatum of Lys-injected Gcdh−/− mice, implying disruption of redox homeostasis. Finally, it was found that Lys provoked alterations of myelin structure reflected by decreased myelin basic protein (MBP) in the cerebral cortex of Gcdh−/−mice. Taken together, the present data demonstrate neuronal loss, gliosis, altered redox homeostasis and demyelination caused by acute Lys overload in brain of Gcdh−/− mice, supporting the hypothesis that increased brain concentrations of glutaric and 3-hydroxyglutaric acids formed from Lys may be responsible for the acute brain degeneration observed in GA I patients during episodes of metabolic decompensation.

Neuroprotection mediated by remote preconditioning is associated with a decrease in systemic oxidative stress and changes in brain and blood glutamate concentration Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): Jana Jachova, Miroslav Gottlieb, Miroslava Nemethova, Lubica Macakova, Martin Bona, Petra Bonova Abstract It has been shown that ischemia of remote organs can generate resistance to ischemic conditions within sensitive brain tissues. However, only limited information about its mechanism is available. In the present paper, we used hind-limb ischemia by tourniquet to generate early remote ischemic tolerance in rats. The main objective was to investigate the role of glutamate in the process of neuroprotection and discover parameters that are affected in the blood of ischemia-affected animals. Our results showed that pretreatment with a hind-limb tourniquet caused a decrease in neurodegeneration by about 30%. However, we did not observe neurological deficit recovery. When compared to ischemia, glutamate concentration decreased in all observed brain regions (cortex, CA1 and dentate gyrus of hippocampus), regardless of their sensitivity to blood restrictions. In contrast to this, the blood levels raised significantly from 26% to 29% during the first four days of postischemic reperfusion. Pretreatment of animals reduced systemic oxidative stress—as represented by lymphocytic DNA damage—by about 80%, while changes in blood antioxidant enzymes (catalase, superoxide dismutase) were not detected. With these data we can further hypothesize that hind-limb-tourniquet preconditioning could accelerate brain-to-blood efflux of glutamate which could positively impact neuronal survival of ischemia-affected brain regions. Moreover, remote preconditioning improved systemic oxidative stress and did not seem to be affected by enzymatic antioxidant defenses in the blood.

Dopamine receptor activation mitigates mitochondrial dysfunction and oxidative stress to enhance dopaminergic neurogenesis in 6-OHDA lesioned rats: A role of Wnt signalling Publication date: October 2019 Source: Neurochemistry International, Volume 129 Author(s): Akanksha Mishra, Sonu Singh, Virendra Tiwari, Swati Chaturvedi, M. Wahajuddin, Shubha Shukla Abstract Nigral dopaminergic (DAergic) cell degeneration and depletion of dopamine neurotransmitter in the midbrain are cardinal features of Parkinson's disease (PD). Dopamine system regulates different aspects of behavioural phenotypes such as motor control, reward, anxiety and depression via acting on dopamine receptors (D1-D5). Recent studies have shown the potential effects of dopamine on modulation of neurogenesis, a process of newborn neuron formation from neural stem cells (NSCs). Reduced proliferative capacity of NSCs and net neurogenesis has been reported in subventricular zone, olfactory bulb and hippocampus of patients with PD. However, the molecular and cellular mechanism of dopamine mediated modulation of DAergic neurogenesis is not defined. In this study, we attempted to investigate the molecular mechanism of dopamine receptors mediated control of DAergic neurogenesis and whether it affects mitochondrial biogenesis in 6-hydroxydopamine (6-OHDA) induced rat model of PD-like phenotypes. Unilateral administration of 6-OHDA into medial forebrain bundle potentially reduced tyrosine hydroxylase immunoreactivity, dopamine content in substantia nigra pars compacta (SNpc) and striatum region and impaired motor functions in adult rats. We found decreased D1 receptor expression, mitochondrial biogenesis, mitochondrial functions and DAergic differentiation associated with down-regulation of Wnt/β-catenin signalling in SNpc of 6-OHDA lesioned rats. Pharmacological stimulation of D1 receptor enhanced mitochondrial biogenesis, mitochondrial functions and DAergic neurogenesis that lead to improved motor functions in 6-OHDA lesioned rats. D1 agonist induced effects were attenuated following administration of D1 antagonist, whereas shRNA mediated knockdown of Axin-2, a negative regulator of Wnt signalling significantly abolished D1 antagonist induced impairment in mitochondrial biogenesis and DAergic neurogenesis in 6-OHDA lesioned rats. Our results suggest that dopamine receptor regulates DAergic neurogenesis and mitochondrial functions by activation of Wnt/β-catenin signaling in rat model of PD-like phenotypes.

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182

6948891480

alsfakia@gmail.com