Vasopressin protects hippocampal neurones in culture against nutrient deprivation or glutamate-induced apoptosis

Mini review of molecules involved in altered postnatal neurogenesis in autism

The neurobiology of autism is complex, but emerging research points to potential abnormalities and alterations in neurogenesis. The aim of the present review is to describe the advances in the understanding of the role of selected neurotrophins, neuropeptides, and other compounds secreted by neuronal cells in the processes of postnatal neurogenesis in conjunction with autism. We characterize the fundamental mechanisms of neuronal cell proliferation, generation of major neuronal cell types with special emphasis on neurogenic niches - the subventricular zone and hippocampal areas. We also discuss changes in intracellular calcium levels and calcium-dependent transcription factors in the context of the regulation of neurogenesis and cell fate determination. To sum up, this review provides specific insight into the known association between alterations in the function of the entire spectrum of molecules involved in neurogenesis and the etiology of autism pathogenesis.

Vasopressin induces apoptosis but does not enhance the antiproliferative effect of dynamin 2 or PI3K/Akt inhibition in luminal A breast cancer cells

Breast cancer cells abnormally express vasopressin (AVP) and its receptors. The effect of AVP is largely orchestrated through its downstream signaling and by receptor-mediated endocytosis (RME), in which Dynamin 2 (Dyn2) plays an integral role in vesicle closure. In this work, luminal A breast cancer cells were treated with AVP, and then Dynasore (DYN) was employed to inhibit Dyn2 to explore the combined effect of AVP and Dyn2 inhibition on the survival of breast cancer cells. The results revealed that DYN alone demonstrated a concentration-dependent cytotoxic effect in AVP untreated cells. Apoptosis developed in 29.7 and 30.3% of cells treated with AVP or AVP+DYN, respectively, compared to 32.5% in cells treated with Wortmannin (Wort, a selective PI3K pathway inhibitor). More apoptosis was observed when cells were treated with DYN+Wort in presence or absence of exogenous AVP. Besides, 2 or 4- fold increases in the expression of Bax and Caspase-3, were observed in cells exposed to AVP in absence or presence of DYN, respectively. This was associated with higher levels of the autophagy marker (LC3II protein). Meanwhile, the activation of Akt protein, sequentially decreased in the same pattern. Cell's invasion decreased when they were exposed to AVP alone or combined with DYN or/and Wort. Conclusively, although many reports suggested the proliferative effect of AVP, the results predict the antiproliferative and antimetastatic effects of 100 nM AVP in luminal A breast cancer cells. However, the hormone did not enhance the cytotoxic effect of Dyn 2 or PI3K pathway inhibition. Summary of the Dynamin 2 independent AVP antiproliferative effects. Breast cancer cells expresses AVP as a Prohormone (A). At high dose of AVP, the hormone is liganded with AVP receptor (B) to initiate RME, where the endosomed complex (C) is degraded through the endosome-lysosome system, as a part of signal management. These events consume soluble Dyn2 in neck closure and vesicle fission (D). This makes the cells more substitutable to the direct apoptotic effect of DYN (E). Alternatively, at lower AVP doses the liganded AVP may initiate cAMP-mediated downstream signaling (F) and cellular proliferation. In parallel, Wort inhibits PIP2-PIP3 conversion (G) and the subsequent inhibition of PI3K/Akt/mTOR pathway leading to cell death.

Cesarean birth elicits long-term effects on vasopressin and oxytocin neurons in the hypothalamic paraventricular nucleus of mice

Birth is an extraordinary event for placental mammals and occurs at a time when key developmental processes are shaping the brain. Remarkably, little is known about the contributions of birth to brain development and whether birth mode (vaginal vs. Cesarean) alters neurodevelopmental trajectories. We previously reported that Cesarean birth reduces vasopressin (VP) neuron number in the hypothalamic paraventricular nucleus (PVN) of mice at weaning. In this study, we investigated whether this effect extends to adulthood and whether birth mode affects oxytocin (OT) neurons, which are another prominent population in the PVN. We found that Cesarean-born adults had fewer VP neurons in the PVN, specifically in magnocellular regions. Interestingly, these regions also had more dying cells following a Cesarean birth, suggesting that cell death may be the underlying mechanism. The PVN of Cesarean-born adults also had smaller VP neuron somas and reduced VP efferent projections. Additionally, Cesarean-born mice showed fewer and smaller OT neurons in the PVN, but these effects were less robust than for VP neurons. We also examined VP and OT neuron number in the supraoptic and suprachiasmatic nuclei but found no effect of birth mode in these regions. Thus, Cesarean birth causes long-term effects on the VP and, to a lesser extent, OT systems in the PVN, suggesting that this region is particularly sensitive to the effects of birth mode. Our findings may help explain the social deficits reported for Cesarean-born mice, and are also of clinical significance given the widespread practice of Cesarean births across the world.

Co-Stimulation of Oxytocin and Arginine-Vasopressin Receptors Affect Hypothalamic Neurospheroid Size

Oxytocin (OXT) is a neuropeptide involved in a plethora of behavioral and physiological processes. However, there is a prominent lack of 3D cell culture models that investigate the effects of OXT on a cellular/molecular level. In this study, we established a hypothalamic neuronal spheroid model to investigate the cellular response in a more realistic 3D setting. Our data indicate that the formation of spheroids itself does not alter the basic characteristics of the cell line and that markers of cellular morphology and connectivity are stably expressed. We found that both OXT and arginine vasopressin (AVP) treatment increase spheroid size (surface area and volume), as well as individual nucleus size, which serves as an indicator for cellular proliferation. The cellular response to both OXT and AVP seems mainly to be mediated by the AVP receptor 1a (V1aR); however, the OXT receptor (OXTR) contributes significantly to the observed proliferative effect. When we blocked the OXTR pharmacologically or knocked down the OXTR by siRNA, the OXT- or AVP-induced cellular proliferation decreased. In summary, we established a 3D cell culture model of the neuronal response to OXT and AVP and found that spheroids react to the treatment via their respective receptors but also via cross-talk between the two receptor types.

Birth elicits a conserved neuroendocrine response with implications for perinatal osmoregulation and neuronal cell death

Long-standing clinical findings report a dramatic surge of vasopressin in umbilical cord blood of the human neonate, but the neural underpinnings and function(s) of this phenomenon remain obscure. We studied neural activation in perinatal mice and rats, and found that birth triggers activation of the suprachiasmatic, supraoptic, and paraventricular nuclei of the hypothalamus. This was seen whether mice were born vaginally or via Cesarean section (C-section), and when birth timing was experimentally manipulated. Neuronal phenotyping showed that the activated neurons were predominantly vasopressinergic, and vasopressin mRNA increased fivefold in the hypothalamus during the 2–3 days before birth. Copeptin, a surrogate marker of vasopressin, was elevated 30-to 50-fold in plasma of perinatal mice, with higher levels after a vaginal than a C-section birth. We also found an acute decrease in plasma osmolality after a vaginal, but not C-section birth, suggesting that the difference in vasopressin release between birth modes is functionally meaningful. When vasopressin was administered centrally to newborns, we found an ~ 50% reduction in neuronal cell death in specific brain areas. Collectively, our results identify a conserved neuroendocrine response to birth that is sensitive to birth mode, and influences peripheral physiology and neurodevelopment.

Neuroprotective effects of miR-142-5p downregulation against isoflurane-induced neurological impairment

Background

Isoflurane can lead to neuron damage to the developing brain, resulting in learning and memory disability. The aim of this study was to investigate the role of miR-142-5p on isoflurane-induced neurological impairment.

Methods

The Morris water maze (MWM) test was performed to evaluate spatial learning and memory of rats. The expression level of miR-142-5p was measured using qRT-PCR. MTT assay was used to calculate the viability of hippocampal neuronal cells. The cell apoptosis was analyzed using Flow cytometric assay.

Results

Isoflurane treatment led to the increase of neurological function score and escape latency, and the reduction of time spent in the original quadrant in rats. The expression level of miR-142-5p was increased significantly in isoflurane-treated rats. MiR-142-5p downregulation protected against isoflurane-induced neurological impairment, which was reflected by the decrease of neurological function score and escape latency, and the increase of time spent in the original quadrant. In vitro, downregulation of miR-142-5p alleviated isoflurane-induced neuron cell viability inhibition, and relieved isoflurane-induced cell apoptosis.

Conclusions

MiR-142-5p downregulation plays a neuroprotective role in protecting against isoflurane-induced neurological impairment through regulating neuron cell viability and apoptosis. It provides a theoretical basis for the investigation of the mechanism underlying the effect on isoflurane-induced neurological impairment.

Does Birth Trigger Cell Death in the Developing Brain?

Developmental cell death eliminates half of the neurons initially generated in the mammalian brain, and occurs perinatally in many species. It is possible that the timing of neuronal cell death is developmentally programmed, and only coincidentally associated with birth. Alternatively, birth may play a role in shaping cell death. To test these competing hypotheses, we experimentally advanced or delayed birth by 1 d in mice (within the normal range of gestation for the species) and examined effects on the temporal pattern and magnitude (amount) of neuronal cell death, using immunohistochemical detection of activated caspase-3 as a cell death marker. In order to detect effects of subtle changes in birth timing, we focused on brain areas that exhibit sharp postnatal peaks in cell death. We find that advancing birth advances peak cell death, supporting the hypothesis that birth triggers cell death. However, a delay of birth does not delay cell death. Thus, birth can advance cell death, but if postponed, a developmental program governs. Advancing or delaying birth also caused region-specific changes in the overall magnitude of cell death. Our findings shed light on the long-standing question of what controls the timing and magnitude of developmental neuronal cell death, and position birth as an orchestrator of brain development. Because humans across the world now routinely alter birth timing, these findings may have implications for current obstetric practices.

Resveratrol protects against cadmium chloride-induced hippocampal neurotoxicity by inhibiting ER stress and GAAD 153 and activating sirtuin 1/AMPK/Akt

This study investigated whether the apoptotic effect induced by cadmium chloride (CdCl₂ ) in rat's hippocampi and neuroprotection afforded by resveratrol (RES) are mediated by modulation of ER stress and involve sirtuin 1 (SIRT1)/AMPK/Akt axis. Adult male Wistar rats were divided into four groups (n = 24/group) as control, control + RES (300 mg/kg), CdCl₂ (5 mg/kg), and CdCl₂  + RES. All treatments were conducted orally for 45 days. Also, cultured hippocampal cells were treated with CdCl₂ in the presence or absence of RES and with or without preincubation with SIRT1, AMPK, or PI3K inhibitors. CdCl₂ impaired retention and spatial memories of rats and reduced levels and activities of SIRT1 and inhibited AMPK/Akt axis in their hippocamapi where SIRT1 was the upstream regulator. It also enahnced hippocampal levels of reactive oxygen species (ROS) and expression of caspase-12 and caspase-3, depleted glutathione (GSH) levels, and activated GRP78, activating transcription factor-6, GAAD 153, X-box binding protein-1 arms of ER stress. On the contrary, RES coadminsitration completley abolished all these events. Interstingly and in control rats, RES not only increased levels of GSH, but also enhenced protein levels of B-cell lymphoma 2 (Bcl-2) and dwonregulated GAAD 153. In both control and CdCl₂ -treated rats, pharmacological inhibtion of SIRT1, AMPK, and Akt compleltely abolished all effects afforded by RES. In conclusion, CdCl₂ -induced hippocampal apopotis is associated with reduction of SIRT1/AMPK/Akt activity levels, ROS generation, downregulation of Bcl-2, and activities, activation of ER stress, and GAAD 153, whereas RES is able to reverse these effects through activation of SIRT1/AMPK/Akt.

Cortisol Excess-Mediated Mitochondrial Damage Induced Hippocampal Neuronal Apoptosis in Mice Following Cold Exposure

Cold stress can induce neuronal apoptosis in the hippocampus, but the internal mechanism involving neuronal loss induced by cold stress is not clear. In vivo, male and female C57BL/6 mice were exposed to 4 °C, 3 h per day for 1 week. In vitro, HT22 cells were treated with different concentrations of cortisol (CORT) for 3 h. In vivo, CORT levels in the hippocampus were measured using ELISA, western blotting, and immunohistochemistry to assess the neuronal population and oxidation of the hippocampus. In vitro, western blotting, immunofluorescence, flow cytometry, transmission electron microscopy, and other methods were used to characterize the mechanism of mitochondrial damage induced by CORT. The phenomena of excessive CORT-mediated oxidation stress and neuronal apoptosis were shown in mouse hippocampus tissue following cold exposure, involving mitochondrial oxidative stress and endogenous apoptotic pathway activation. These processes were mediated by acetylation of lysine 9 of histone 3, resulting in upregulation involving Adenosine 5'-monophosphate (AMP)-activated protein kinase (APMK) phosphorylation and translocation of Nrf2 to the nucleus. In addition, oxidation in male mice was more severe. These findings provide a new understanding of the underlying mechanisms of the cold stress response and explain the apoptosis process induced by CORT, which may influence the selection of animal models in future stress-related studies.

Melatonin Improves Memory Deficits in Rats with Cerebral Hypoperfusion, Possibly, Through Decreasing the Expression of Small-Conductance Ca2+-Activated K+ Channels

This study investigated the expression pattern, regulation of expression, and the role of hippocampal small-conductance Ca²⁺-activated K⁺ (SK) channels in memory deficits after cerebral hypoperfusion (CHP) with or without melatonin treatment, in rats. Adults male Wistar rats (n = 20/group) were divided into (1) a sham (2) a sham + melatonin (3) a two-vessel occlusion (2-VO) model, and (4) a 2-VO + melatonin. Melatonin was administered (i.p.) to all rats at a daily dose of 10 mg kg^-1 for 7 days starting at the time of 2-VO-induction. In contrast to 2-VO rats, melatonin increased the latency of the passive avoidance learning test and decreased time to find the hidden platform in Water Morris Test in all tested rats. In addition, it concomitantly downregulated SK1, SK2, and SK3 channels, downregulated mRNA levels of TNFα and IL-1β, enhanced BDNF levels and activity of PKA levels, and restored the levels of cholinergic markers in the hippocampi of the treated-rats. Mechanistically, melatonin significantly prevented CHP-induced activation of ERK1/2, JNK, and P38 MAPK at least by inhibiting ROS generation and enhancing the total antioxidant potential. In cultured hypoxic hippocampal neurons, individual blockage of MAPK signaling by the MEK1/2 inhibitor (U0126), but not by the P38 inhibitor (SB203580) or JNK inhibitor (SP600125), completely prevented the upregulation of all three kinds of SK channels. These data clearly confirm that upregulation of SK channels plays a role in CHP-induced memory loss and indicate that melatonin reverses memory deficits after CHP in rats, at least by, downregulation of SK1, SK2, and SK3 channels in their hippocampi.

Screening of novel 3α5β-neurosteroids for neuroprotective activity against glutamate- or NMDA-induced excitotoxicity

A broad variety of central nervous system diseases have been associated with glutamate induced excitotoxicity under pathological conditions. The neuroprotective effects of neurosteroids can combat this excitotoxicity. Herein, we have demonstrated the neuroprotective effect of novel steroidal N-methyl-D-aspartate receptor inhibitors against glutamate- or NMDA- induced excitotoxicity. Pretreatment with neurosteroids significantly reduced acute L-glutamic acid or NMDA excitotoxicity mediated by Ca²⁺ entry and consequent ROS (reactive oxygen species) release and caspase-3 activation. Compounds 6 (IC₅₀ = 5.8 μM), 7 (IC₅₀ = 12.2 μM), 9 (IC₅₀ = 7.8 μM), 13 (IC₅₀ = 1.1 μM) and 16 (IC₅₀ = 8.2 μM) attenuated glutamate-induced Ca²⁺ entry more effectively than memantine (IC₅₀ = 18.9 μM). Moreover, compound 13 shows comparable effect with MK-801 (IC₅₀ = 1.2 μM) and also afforded significant protection without any adverse effect upon prolonged exposure. This drop in Ca²⁺ level resulted in corresponding ROS suppression and prevented glutamate-induced caspase-3 activation. Therefore, compound 13 has great potential for development into a therapeutic agent for improving glutamate-related nervous system diseases.

Activation of the MAPK signaling pathway induces upregulation of pro-apoptotic proteins in the hippocampi of cold stressed adolescent mice

Stress induces many non-specific responses in the hippocampus, especially during adolescence. Low environmental temperature is known to induce stress, but its influence on the hippocampus, especially in adolescent mice is not clear. We compared apoptotic-related protein levels and MAPK signaling pathway activation in hippocampal neurons of adolescent mice under low temperature conditions (4 °C for 12 h) with western blotting and immunohistochemistry. Western bolt results demonstrated that the levels of phospho-JNK, phospho-p38, and cleaved-caspase 3 significantly increased, while the ratio of Bcl-XL/Bax decreased, in the cold stress group. The results of immunohistochemistry (IHC) and Nissl staining demonstrated that the protein optical density of caspase 3 increased and Nissl bodies decreased in the cold stress group compared with controls. Thus, we conclude that cold exposure initiates activation of the MAPK signaling pathway and subsequently induces the upregulation of pro-apoptotic proteins in the hippocampi of adolescent mice. Overall our study reveals the relationship between cold stress and apoptosis in adolescent mice.

Birth delivery mode alters perinatal cell death in the mouse brain

Labor and a vaginal delivery trigger changes in peripheral organs that prepare the mammalian fetus to survive ex utero. Surprisingly little attention has been given to whether birth also influences the brain, and to how alterations in birth mode affect neonatal brain development. These are important questions, given the high rates of cesarean section (C-section) delivery worldwide, many of which are elective. We examined the effect of birth mode on neuronal cell death, a widespread developmental process that occurs primarily during the first postnatal week in mice. Timed-pregnant dams were randomly assigned to C-section deliveries that were yoked to vaginal births to carefully match gestation length and circadian time of parturition. Compared with rates of cell death just before birth, vaginally-born offspring had an abrupt, transient decrease in cell death in many brain regions, suggesting that a vaginal delivery is neuroprotective. In contrast, cell death was either unchanged or increased in C-section-born mice. Effects of delivery mode on cell death were greatest for the paraventricular nucleus of the hypothalamus (PVN), which is central to the stress response and brain-immune interactions. The greater cell death in the PVN of C-section-delivered newborns was associated with a reduction in the number of PVN neurons expressing vasopressin at weaning. C-section-delivered mice also showed altered vocalizations in a maternal separation test and greater body mass at weaning. Our results suggest that vaginal birth acutely impacts brain development, and that alterations in birth mode may have lasting consequences.

GABAB receptor mediate hippocampal neuroinflammation in adolescent male and female mice after cold expose

Stress induces many non-specific inflammatory responses in the mouse brain, especially during adolescence. Although the impact of stress on the brain has long been reported, the effects of cold stress on hippocampal neuroinflammation in adolescent mice are not well understood; furthermore, whether these effects are gender specific are also not well established. Adolescent male and female C57BL/6 mice were exposed to 4 °C temperatures for 12 h, after which behavior was assessed using the open field test. Using western blotting and immunohistochemistry we also assessed glial cell numbers and microglial activation, as well as inflammatory cytokine levels and related protein expression levels. We found that in mice subjected to cold stress: 1) There were significant behavioral changes; 2) neuronal nuclei densities were smaller and total cell numbers were significantly decreased; 3) nuclear factor (NF)-κB and phosphorylated AKT were upregulated; 4) pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-α were also upregulated; and 5) microglia were activated, while glial fibrillary acid protein and ionized calcium-binding adapter molecule 1 protein expression increased. Taken together, these results indicate that cold stress induces pro-inflammatory cytokine upregulation that leads to neuroinflammation and neuronal apoptosis in the hippocampi of adolescent mice. We believe that these effects are influenced by a GABAB/Rap1B/AKT/NF-κB pathway. Finally, male mice were more sensitive to the effects of cold stress than were female mice.

Vasopressin excites interneurons to suppress hippocampal network activity across a broad span of brain maturity at birth

During birth in mammals, a pronounced surge of fetal peripheral stress hormones takes place to promote survival in the transition to the extrauterine environment. However, it is not known whether the hormonal signaling involves central pathways with direct protective effects on the perinatal brain. Here, we show that arginine vasopressin specifically activates interneurons to suppress spontaneous network events in the perinatal hippocampus. Experiments done on the altricial rat and precocial guinea pig neonate demonstrated that the effect of vasopressin is not dependent on the level of maturation (depolarizing vs. hyperpolarizing) of postsynaptic GABA_A receptor actions. Thus, the fetal mammalian brain is equipped with an evolutionarily conserved mechanism well-suited to suppress energetically expensive correlated network events under conditions of reduced oxygen supply at birth.

The Effect of Acute and Chronic Social Stress on the Hippocampal Transcriptome in Mice

Psychogenic stress contributes to the formation of brain pathology. Using gene expression microarrays, we analyzed the hippocampal transcriptome of mice subjected to acute and chronic social stress of different duration. The longest period of social stress altered the expression of the highest number of genes and most of the stress-induced changes in transcription were reversible after 5 days of rest. Chronic stress affected genes involved in the functioning of the vascular system (Alas2, Hbb-b1, Hba-a2, Hba-a1), injury response (Vwf, Mgp, Cfh, Fbln5, Col3a1, Ctgf) and inflammation (S100a8, S100a9, Ctla2a, Ctla2b, Lcn2, Lrg1, Rsad2, Isg20). The results suggest that stress may affect brain functions through the stress-induced dysfunction of the vascular system. An important issue raised in our work is also the risk of the contamination of brain tissue samples with choroid plexus. Such contamination would result in a consistent up- or down-regulation of genes, such as Ttr, Igf2, Igfbp2, Prlr, Enpp2, Sostdc1, 1500015O10RIK (Ecrg4), Kl, Clic6, Kcne2, F5, Slc4a5, and Aqp1. Our study suggests that some of the previously reported, supposedly specific changes in hippocampal gene expression, may be a result of the inclusion of choroid plexus in the hippocampal samples.

Totarol prevents neuronal injury in vitro and ameliorates brain ischemic stroke: Potential roles of Akt activation and HO-1 induction

The natural product totarol, a phenolic diterpenoid and a major constituent isolated from the sap of Podocarpus totara, has been reported to have a potent antimicrobial activity. In this study, we determined whether totarol possessed an additional neuroprotective activity in vitro and in vivo. We found that totarol prevented glutamate- and oxygen and glucose deprivation-induced neuronal death in primary rat cerebellar granule neuronal cells and cerebral cortical neurons. Totarol increased Akt and GSK-3β phosphorylation, Nrf2 and heme oxygenase-1 (HO-1) protein expressions and suppressed oxidative stress by increasing GSH and SOD activities. The PI3K/Akt inhibitor LY294002 prevented totarol neuroprotective effect by suppressing the totarol-induced changes in HO-1 expression and the activities of GSH and SOD. The HO-1 inhibitor ZnPPIX also prevented totarol-increased GSH and SOD activities. In a model of acute cerebral ischemic injury in Sprague-Dawley rats, produced by occlusion of the middle cerebral artery for 2h followed by 22 h or 46 h of reperfusion, totarol significantly reduced infarct volume and improved the neurological deficit. In this model, totarol increased HO-1 expression and the activities of GSH and SOD. These observations suggest that totarol may be a novel activator of the Akt/HO-1 pathway protecting against ischemic stroke through reduction of oxidative stress.

Interaction of stress, corticotropin-releasing factor, arginine vasopressin and behaviour

Stress mediates the activation of a variety of systems ranging from inflammatory to behavioral responses. In this review we focus on two neuropeptide systems, corticotropin-releasing factor (CRF) and arginine vasopressin (AVP), and their roles in regulating stress responses. Both peptides have been demonstrated to be involved in anxiogenic and depressive effects, actions mediated in part through their regulation of the hypothalamic-pituitary-adrenal axis and the release of adrenocorticotropic hormone. Because of the depressive effects of CRF and AVP, drugs modifying the stress-associated detrimental actions of CRF and AVP are under development, particularly drugs antagonizing CRF and AVP receptors for therapy in depression.

BAFF controls neural cell survival through BAFF receptor

Various neuroprotective factors have been shown to help prevention of neuronal cell death, which is responsible for the progression of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). However, most of these therapeutic potentials have been tested by administration of recombinant proteins, transgenic expression or virus vector-mediated gene transfer. Therefore, it remains to be clarified whether any endogenous factors has advantage for neuroprotection in a pathological nervous system. Here we show the role of BAFF-R signaling pathway in the control of neural cell survival. Both B cell–activating factor (BAFF) and its receptor (BAFF-R) are expressed in mouse neurons and BAFF-R deficiency reduces the survival of primary cultured neurons. Although many studies have so far addressed the functional role of BAFF-R on the differentiation of B cells, impaired BAFF-R signaling resulted in accelerated disease progression in an animal model of inherited ALS. We further demonstrate that BAFF-R deficient bone marrow cells or genetic depletion of B cells does not affect the disease progression, indicating that BAFF-mediated signals on neurons, not on B cells, support neural cell survival. These findings suggest opportunities to improve therapeutic outcome for patients with neurodegenerative diseases by synthesized BAFF treatment.

Amelioration of rotenone-induced dopaminergic cell death in the striatum by oxytocin treatment

Oxytocin (OT) is essentially associated with uterine contraction during parturition and milk ejection reflex. Although several studies implicate the role of OT in anti-inflammatory, anti-oxidative and anti-apoptotic pathways, there is a lack of data with regard to the protective effects of oxytocin in neurodegenerative models such as Parkinson's disease (PD). The present study was undertaken to investigate the neuroprotective effects of oxytocin (OT) on rotenone-induced PD in rats. Twenty adult Sprague-Dawley rats were injected with rotenone (3 μg/μl in DMSO) or vehicle (1 μl DMSO) into the left substantia nigra pars compacta (SNc) and ventral tegmental area (VTA) under stereotaxic surgery, and PD model was assessed by rotational test ten days after drug infusion. The valid PD rats were randomly divided into two groups; Group 1 (n=7) and Group 2 (n=7) were administered saline (1 ml/kg/day, i.p.) and oxytocin (160 μg/kg/day, i.p.) through 20 days, respectively. The effects of OT treatment were evaluated by behavioral, histological and immunohistochemical parameters. Apomorphine-induced stereotypic rotations in PD rats were significantly inhibited by OT treatment (p<0.05). In addition, immunohistochemical studies clearly demonstrated the suppression of Bax, caspase-3, caspase-8 and elevation of Bcl-2 and tyrosine hydroxylase immunoexpression in OT-treated rats compared to saline group. Our findings suggest that oxytocin may have cytoprotective and restorative effects on dopaminergic neurons against rotenone-induced injury. The underlying mechanism may be associated with the inhibition of apoptotic pathways.

HPA axis responsiveness to stress: implications for healthy aging

The major neuroendocrine response mediating stress adaptation is activation of the hypothalamic pituitary adrenal axis, with stimulation of corticotropin releasing hormone (CRH) and vasopressin (VP) from parvocellular neurons of the hypothalamic paraventricular nucleus, leading to stimulation of pituitary ACTH secretion and increases in glucocorticoid secretion from the adrenal cortex. Basal production and transient increases during stress of glucocorticoids and its hypothalamic regulators are essential for neuronal plasticity and normal brain function. While activation of the HPA axis is essential for survival during stress, chronic exposure to stress hormones can predispose to psychological, metabolic and immune alterations. Thus, prompt termination of the stress response is essential to prevent negative effects of inappropriate levels of CRH and glucocorticoids. This review addresses the regulation of HPA axis activity with emphasis on the mechanisms of termination of CRH transcription, which is a critical step in this process. In addition, the actions by which glucocorticoids, CRH and VP can affect the aging process will be discussed.