NAP enhances neurodevelopment of newborn apolipoprotein E-deficient mice subjected to hypoxia

The role of ApoE in fatty acid transport from neurons to astrocytes under ischemia/hypoxia conditions

BACKGROUND

The aim of this study was to investigate whether ischemia/hypoxia conditions induce fatty acid transport from neurons to astrocytes and whether this mechanism is affected by ApoE isoforms.

METHODS AND RESULTS

A neonatal rat model of hypoxic-ischemic brain damage was established. Excessive accumulation of lipid droplets and upregulation of ApoE expression occurred in the hippocampus and cerebral cortex after hypoxia-ischemia, which implied the occurrence of abnormal fatty acid metabolism. Lipid peroxidation was induced in an oxygen-glucose deprivation and reperfusion (OGDR) model of ApoE-/- primary neurons. The number of BODIPY 558/568 C12-positive particles (fatty acid markers) transferred from neurons to astrocytes was significantly increased with the addition of human recombinant ApoE compared with that in the OGDR group, which significantly increased the efficiency of fatty acid transport from neurons to astrocytes and neuronal viability. However, ApoE4 was found to be associated with lower efficiency in fatty acid transport and less protective effects in OGDR-induced neuronal cell death than both ApoE2 and ApoE3. COG133, an ApoE-mimetic peptide, partially compensated for the adverse effects of ApoE4. FABP5 and SOD1 gene and protein expression levels were upregulated in astrocytes treated with BODIPY 558/568 C12 particles.

CONCLUSIONS

In conclusion, ApoE plays an important role in mediating the transport of fatty acids from neurons to astrocytes under ischemia/hypoxia conditions, and this transport mechanism is ApoE isoform dependent. ApoE4 has a low transfer efficiency and may be a potential target for the clinical treatment of neonatal hypoxic-ischemic encephalopathy.

Perinatal Brain Injury and Inflammation: Lessons from Experimental Murine Models

Perinatal brain injury or neonatal encephalopathy (NE) is a state of disturbed neurological function in neonates, caused by a number of different aetiologies. The most prominent cause of NE is hypoxic ischaemic encephalopathy, which can often induce seizures. NE and neonatal seizures are both associated with poor neurological outcomes, resulting in conditions such as cerebral palsy, epilepsy, autism, schizophrenia and intellectual disability. The current treatment strategies for NE and neonatal seizures have suboptimal success in effectively treating neonates. Therapeutic hypothermia is currently used to treat NE and has been shown to reduce morbidity and has neuroprotective effects. However, its success varies between developed and developing countries, most likely as a result of lack of sufficient resources. The first-line pharmacological treatment for NE is phenobarbital, followed by phenytoin, fosphenytoin and lidocaine as second-line treatments. While these drugs are mostly effective at halting seizure activity, they are associated with long-lasting adverse neurological effects on development. Over the last years, inflammation has been recognized as a trigger of NE and seizures, and evidence has indicated that this inflammation plays a role in the long-term neuronal damage experienced by survivors. Researchers are therefore investigating the possible neuroprotective effects that could be achieved by using anti-inflammatory drugs in the treatment of NE. In this review we will highlight the current knowledge of the inflammatory response after perinatal brain injury and what we can learn from animal models.

Microtubule Dysfunction: A Common Feature of Neurodegenerative Diseases

Neurons are particularly susceptible to microtubule (MT) defects and deregulation of the MT cytoskeleton is considered to be a common insult during the pathogenesis of neurodegenerative disorders. Evidence that dysfunctions in the MT system have a direct role in neurodegeneration comes from findings that several forms of neurodegenerative diseases are associated with changes in genes encoding tubulins, the structural units of MTs, MT-associated proteins (MAPs), or additional factors such as MT modifying enzymes which modulating tubulin post-translational modifications (PTMs) regulate MT functions and dynamics. Efforts to use MT-targeting therapeutic agents for the treatment of neurodegenerative diseases are underway. Many of these agents have provided several benefits when tested on both in vitro and in vivo neurodegenerative model systems. Currently, the most frequently addressed therapeutic interventions include drugs that modulate MT stability or that target tubulin PTMs, such as tubulin acetylation. The purpose of this review is to provide an update on the relevance of MT dysfunctions to the process of neurodegeneration and briefly discuss advances in the use of MT-targeting drugs for the treatment of neurodegenerative disorders.

Immune-modulatory Properties of the Octapeptide NAP in Campylobacter jejuni Infected Mice Suffering from Acute Enterocolitis

Human infections with the food-borne zoonotic pathogen Campylobacter jejuni are progressively rising and constitute serious global public health and socioeconomic burdens. Hence, application of compounds with disease-alleviating properties are required to combat campylobacteriosis and post-infectious sequelae. In our preclinical intervention study applying an acute C. jejuni induced enterocolitis model, we surveyed the anti-pathogenic and immune-modulatory effects of the octapeptide NAP which is well-known for its neuroprotective and anti-inflammatory properties. Therefore, secondary abiotic IL-10^−/− mice were perorally infected with C. jejuni and intraperitoneally treated with synthetic NAP from day 2 until day 5 post-infection. NAP-treatment did not affect gastrointestinal C. jejuni colonization but could alleviate clinical signs of infection that was accompanied by less pronounced apoptosis of colonic epithelial cells and enhancement of cell regenerative measures on day 6 post-infection. Moreover, NAP-treatment resulted in less distinct innate and adaptive pro-inflammatory immune responses that were not restricted to the intestinal tract but could also be observed in extra-intestinal and even systemic compartments. NAP-treatment further resulted in less frequent translocation of viable pathogens from the intestinal tract to extra-intestinal including systemic tissue sites. For the first time, we here provide evidence that NAP application constitutes a promising option to combat acute campylobacteriosis.

Early-life N-arachidonoyl-dopamine exposure increases antioxidant capacity of the brain tissues and reduces functional deficits after neonatal hypoxia in rats

Perinatal hypoxia-ischemia is one of the most common causes of perinatal brain injury and subsequent neurological disorders in children. The aim of this work was to evaluate the potential antioxidant and neuroprotective effects of N-arachidonoyl-dopamine (NADA) in the model of acute neonatal hypoxia (ANH) in rat pups. Male and female Wistar rats were exposed to a hypoxic condition (8% oxygen for 120 min) at postnatal day 2 (P2). Transcription factor HIF1-α and glutathione peroxidases GPx2 and GPx4 gene expression was increased in rat brains in the hypoxic group compared to control 1.5 h but not 4 days after ANH. There were no post-hypoxic changes in reduced (GSH) and oxidised (GSSG) glutathione levels in the brain of rat pups 1.5 h and 4 d after hypoxia. Hypoxic rats displayed retarded performance in the righting reflex and the negative geotaxis tests. ANH resulted in increased ambulation in Open field test and impaired retention in the Barnes maze task under stressful conditions as compared with the control group. Treatment with NADA significantly attenuated the delayed development of sensorimotor reflexes and stress-evoked disruption of memory retention in hypoxic rats but had no effect on the hypoxia-induced hyperactivity. In rats exposed to hypoxia, treatment with NADA decreased GPx2 gene expression and increased GSH/GSSG ratio in whole brains 1.5 h after ANH. These results suggest that the long-lasting beneficial effects of NADA on hypoxia-induced neurobehavioural deficits are mediated, at least in part, by its antioxidant properties.

Atypical Auditory Brainstem Response and Protein Expression Aberrations Related to ASD and Hearing Loss in the Adnp Haploinsufficient Mouse Brain

Autism is a wide spread neurodevelopmental disorder with growing morbidity rates, affecting more boys than girls worldwide. Activity-dependent neuroprotective protein (ADNP) was recently recognized as a leading gene accounted for 0.17% of autism spectrum disorder (ASD) cases globally. Respectively, mutations in the human ADNP gene (ADNP syndrome), cause multi-system body dysfunctions with apparent ASD-related traits, commencing as early as childhood. The Adnp haploinsufficient (Adnp^+/-) mouse model was researched before in relations to Alzheimer's disease and autism. Adnp^+/- mice suffer from deficient social memory, vocal and motor impediments, irregular tooth eruption and short stature, all of which corresponds with reported phenotypes in patients with the ADNP syndrome. Recently, a more elaborated description of the ADNP syndrome was published, presenting impediments such as hearing disabilities in > 10% of the studied children. Irregular auditory brainstem response (ABR) has been connected to ASD-related cases and has been suggested as a potential hallmark for autism, allowing diagnosis of ASD risk and early intervention. Herein, we present detriment hearing in the Adnp^+/- mice with atypical ABR and significant protein expression irregularities that coincides with ASD and hearing loss studies in the brain.

Activity-dependent neuroprotective protein deficiency models synaptic and developmental phenotypes of autism-like syndrome

Previous findings showed that in mice, complete knockout of activity-dependent neuroprotective protein (ADNP) abolishes brain formation, while haploinsufficiency (Adnp+/-) causes cognitive impairments. We hypothesized that mutations in ADNP lead to a developmental/autistic syndrome in children. Indeed, recent phenotypic characterization of children harboring ADNP mutations (ADNP syndrome children) revealed global developmental delays and intellectual disabilities, including speech and motor dysfunctions. Mechanistically, ADNP includes a SIP motif embedded in the ADNP-derived snippet drug candidate NAP (NAPVSIPQ, also known as CP201), which binds to microtubule end-binding protein 3, essential for dendritic spine formation. Here, we established a unique neuronal membrane-tagged, GFP-expressing Adnp+/- mouse line allowing in vivo synaptic pathology quantification. We discovered that Adnp deficiency reduced dendritic spine density and altered synaptic gene expression, both of which were partly ameliorated by NAP treatment. Adnp+/-mice further exhibited global developmental delays, vocalization impediments, gait and motor dysfunctions, and social and object memory impairments, all of which were partially reversed by daily NAP administration (systemic/nasal). In conclusion, we have connected ADNP-related synaptic pathology to developmental and behavioral outcomes, establishing NAP in vivo target engagement and identifying potential biomarkers. Together, these studies pave a path toward the clinical development of NAP (CP201) for the treatment of ADNP syndrome.

Anti-inflammatory Effects of the Octapeptide NAP in Human Microbiota-Associated Mice Suffering from Subacute Ileitis

The octapeptide NAP is well known for its neuroprotective properties. We here investigated whether NAP treatment could alleviate pro-inflammatory immune responses during experimental subacute ileitis. To address this, mice with a human gut microbiota were perorally infected with one cyst of Toxoplasma gondii (day 0) and subjected to intraperitoneal synthetic NAP treatment from day 1 until day 8 postinfection (p.i.). Whereas placebo (PLC) control animals displayed subacute ileitis at day 9 p.i., NAP-treated mice exhibited less pronounced pro-inflammatory immune responses as indicated by lower numbers of intestinal mucosal T and B lymphocytes and lower interferon (IFN)-γ concentrations in mesenteric lymph nodes. The NAP-induced anti-inflammatory effects were not restricted to the intestinal tract but could also be observed in extra-intestinal including systemic compartments, given that pro-inflammatory cytokines were lower in liver, kidney, and lung following NAP as compared to PLC application, whereas at day 9 p.i., colonic and serum interleukin (IL)-10 concentrations were higher in the former as compared to the latter. Remarkably, probiotic commensal bifidobacterial loads were higher in the ileal lumen of NAP as compared to PLC-treated mice with ileitis. Our findings thus further support that NAP might be regarded as future treatment option directed against intestinal inflammation.

Gender-dependent changes in physical development, BDNF content and GSH redox system in a model of acute neonatal hypoxia in rats

Perinatal hypoxia-ischaemia is one of the leading factors that negatively influence the development of the central nervous system. Our aim was to investigate the effects of sex on the outcomes of acute neonatal hypoxia (ANH) in rat pups. Male and female Wistar rats were exposed to a hypoxic condition (8% oxygen for 120 min) at postnatal day 2 (P2). Immediately after ANH an increase in HIF1-α gene expression was observed in the rat brains, independently of sex. Brain-derived neurotrophic factor (BDNF) and glutathione peroxidase-4 gene expression was increased in female animals only. Hypoxic pups of both sexes showed a decreased reduced/oxidised glutathione (GSH/GSSG) ratio in the blood and only males had an increased GSH content in the whole brain immediately after hypoxia. Furthermore, an increased BDNF content in the brain was found in both male and female rat pups at 0 h and in serum 4 h after hypoxia, but at 4 h after hypoxia only males had an increased BDNF level in the brain. Only hypoxic males displayed retarded performance in the righting reflex, but in a negative geotaxis test hypoxic pups of both sexes had an increased turnaround time. Moreover, hypoxic female but not male pups demonstrated less weight gain than control littermates for the entire observation period (until P18). These results demonstrate that ANH at P2 leads to both molecular and physiological impairments in a sex-specific manner and the described model could be used to represent mild hypoxic brain damage in very preterm infants.

The octapetide NAP alleviates intestinal and extra-intestinal anti-inflammatory sequelae of acute experimental colitis

The octapeptide NAP has been shown to exert neuroprotective properties and reduce neuro-inflammatory responses. The aim of the present study was to investigate if NAP provides anti-inflammatory effects in acute murine colitis. To address this, C57BL/6 j mice were challenged with 3.5% dextran sulfate sodium from day 0 until day 6 to induce colitis, either treated intraperitoneally with NAP or placebo (NaCl 0.9%) from day 1 until day 6 post-induction (p.i.) and subjected to in depth macroscopic, microscopic and immunological evaluations. Whereas NAP application did not alleviate macroscopic (i.e. clinical) sequelae of colitis, lower numbers of apoptotic, but higher counts of proliferating/regenerating colonic epithelial cells could be observed in NAP as compared to placebo treated mice at day 7 p.i. Furthermore, lower numbers of adaptive immune cells such as T lymphocytes and regulatory T cells were abundant in the colonic mucosa and lamina propria upon NAP versus placebo treatment that were accompanied by less colonic secretion of pro-inflammatory mediators including IFN-γ and nitric oxide at day 7 p.i. In mesenteric lymph nodes, pro-inflammatory IFN-γ, TNF and IL-6 concentrations were increased in placebo, but not NAP treated mice at day 7 p.i., whereas interestingly, elevated anti-inflammatory IL-10 levels could be observed in NAP treated mice only. The assessed anti-inflammatory properties of NAP were not restricted to the intestinal tract, given that in extra-intestinal compartments such as the kidneys, IFN-γ levels increased in placebo, but not NAP treated mice upon colitis induction. NAP induced effects were accompanied by distinct changes in intestinal microbiota composition, given that colonic luminal loads of bifidobacteria, regarded as anti-inflammatory, "health-promoting" commensal species, were two orders of magnitude higher in NAP as compared to placebo treated mice and even naive controls. In conclusion, NAP alleviates intestinal and extra-intestinal pro-inflammatory sequelae of acute experimental colitis and may provide novel treatment options of intestinal inflammatory diseases in humans.

Neonatal Hypoxia Ischaemia: Mechanisms, Models, and Therapeutic Challenges

Neonatal hypoxia-ischaemia (HI) is the most common cause of death and disability in human neonates, and is often associated with persistent motor, sensory, and cognitive impairment. Improved intensive care technology has increased survival without preventing neurological disorder, increasing morbidity throughout the adult population. Early preventative or neuroprotective interventions have the potential to rescue brain development in neonates, yet only one therapeutic intervention is currently licensed for use in developed countries. Recent investigations of the transient cortical layer known as subplate, especially regarding subplate's secretory role, opens up a novel set of potential molecular modulators of neonatal HI injury. This review examines the biological mechanisms of human neonatal HI, discusses evidence for the relevance of subplate-secreted molecules to this condition, and evaluates available animal models. Neuroserpin, a neuronally released neuroprotective factor, is discussed as a case study for developing new potential pharmacological interventions for use post-ischaemic injury.

The Eight and a Half Year Journey of Undiagnosed AD: Gene Sequencing and Funding of Advanced Genetic Testing Has Led to Hope and New Beginnings

BACKGROUND

Activity-dependent neuroprotective protein (ADNP) is one of the most prevalent de novo mutated genes in syndromic autism spectrum disorders, driving a general interest in the gene and the syndrome.

AIM

The aim of this study was to provide a detailed developmental case study of ADNP p.Tyr719* mutation toward improvements in (1) diagnostic procedures, (2) phenotypic scope, and (3) interventions.

METHODS

Longitudinal clinical and parental reports.

RESULTS

AD (currently 11-year-old) had several rare congenital anomalies including imperforate anus that was surgically repaired at 2 days of age. Her findings were craniofacial asymmetries, global developmental delay, autistic behaviors (loss of smile and inability to make eye contact at the age of 15 months), and slow thriving as she gradually matures. Comprehensive diagnostic procedures at 3 years resulted in no definitive diagnosis. With parental persistence, AD began walking at 3.5 years (skipping crawling). At the age of 8.5 years, AD was subjected to whole exome sequencing, compared to the parents and diagnosed as carrying an ADNP p.Tyr719* mutation, a causal recurring mutation in ADNP (currently ~17/80 worldwide). Brain magnetic resonance imaging demonstrated mild generalized cerebral volume loss with reduced posterior white matter. AD is non-verbal, communicating with signs and word approximations. She continues to make slow but forward developmental progress, and her case teaches newly diagnosed children within the ADNP Kids Research Foundation.

CONCLUSION

This case study emphasizes the importance of diagnosis and describes, for the first time, early motor intervention therapies. Detailed developmental profile of selected cases leads to better treatments.

Prolonged maternal separation induces undernutrition and systemic inflammation with disrupted hippocampal development in mice

OBJECTIVE

Prolonged maternal separation (PMS) in the first 2 wk of life has been associated with poor growth with lasting effects in brain structure and function. This study aimed to investigate whether PMS-induced undernutrition could cause systemic inflammation and changes in nutrition-related hormonal levels, affecting hippocampal structure and neurotransmission in C57BL/6J suckling mice.

METHODS

This study assessed mouse growth parameters coupled with insulin-like growth factor-1 (IGF-1) serum levels. In addition, leptin, adiponectin, and corticosterone serum levels were measured following PMS. Hippocampal stereology and the amino acid levels were also assessed. Furthermore, we measured myelin basic protein and synapthophysin (SYN) expression in the overall brain tissue and hippocampal SYN immunolabeling. For behavioral tests, we analyzed the ontogeny of selected neonatal reflexes. PMS was induced by separating half the pups in each litter from their lactating dams for defined periods each day (4 h on day 1, 8 h on day 2, and 12 h thereafter). A total of 67 suckling pups were used in this study.

RESULTS

PMS induced significant slowdown in weight gain and growth impairment. Significant reductions in serum leptin and IGF-1 levels were found following PMS. Total CA3 area and volume were reduced, specifically affecting the pyramidal layer in PMS mice. CA1 pyramidal layer area was also reduced. Overall hippocampal SYN immunolabeling was lower, especially in CA3 field and dentate gyrus. Furthermore, PMS reduced hippocampal aspartate, glutamate, and gamma-aminobutyric acid levels, as compared with unseparated controls.

CONCLUSION

These findings suggest that PMS causes significant growth deficits and alterations in hippocampal morphology and neurotransmission.

Anti-Inflammatory Properties of NAP in Acute Toxoplasma Gondii-Induced Ileitis in Mice

The octapeptide NAP has been shown to exert neuroprotective properties. Here, we investigated potential anti-inflammatory effects of NAP in an acute ileitis model. To address this, C57BL/6j mice were perorally infected with Toxoplasma gondii (day 0). Within 1 week postinfection (p.i.), placebo (PLC)-treated mice developed acute ileitis due to Th1-type immune responses. Mice that were subjected to intraperitoneal NAP treatment from day 1 until day 6 p.i., however, developed less distinct macroscopic and microscopic disease as indicated by less body weight loss, less distinct histopathological ileal changes, and lower ileal apoptotic, but higher proliferating cell numbers, less abundance of neutrophils, macrophages, monocytes, and T lymphocytes, but higher numbers of regulatory T cells in the ileal mucosa and lamina propria, and lower concentrations of pro-inflammatory mediators in the ilea as compared to PLC controls at day 7 p.i. Remarkably, NAP-mediated anti-inflammatory effects could also be observed in extra-intestinal compartments including liver and spleen. Strikingly, lower MCP-1, TNF, and IL-12p70 serum concentrations in NAP as compared to PLC-treated mice at day 7 p.i. indicate a pronounced systemic anti-inflammatory effect of NAP in acute ileitis. These findings provide first evidence for NAP as a potential novel treatment option in intestinal inflammation.

NAP (davunetide) rescues neuronal dysfunction in a Drosophila model of tauopathy

Alzheimer's disease (AD) is a devastating neurodegenerative disease causing irreversible cognitive decline in the elderly. There is no disease-modifying therapy for this condition and the mechanisms underpinning neuronal dysfunction and neurodegeneration are unclear. Compromised cytoskeletal integrity within neurons is reported in AD. This is believed to result from loss-of-function of the microtubule-associated protein tau, which becomes hyper-phosphorylated and deposits into neurofibrillary tangles in AD. We have developed a Drosophila model of tauopathy in which abnormal human tau mediates neuronal dysfunction characterised by microtubule destabilisation, axonal transport disruption, synaptic defects and behavioural impairments. Here we show that a microtubule-stabilising drug, NAPVSIPQ (NAP), prevents as well as reverses these phenotypes even after they have become established. Moreover, it does not alter abnormal tau levels indicating that it by-passes toxic tau altogether. Thus, microtubule stabilisation is a disease-modifying therapeutic strategy protecting against tau-mediated neuronal dysfunction, which holds great promise for tauopathies like AD.

VIP-induced neuroprotection of the developing brain

Excitotoxicity is a key molecular mechanism of perinatal brain damage and is associated with cerebral palsy and long term cognitive deficits. VIP induces a potent neuroprotection against perinatal excitotoxic white matter damage. VIP does not prevent the initial appearance of white matter lesion but promotes a secondary repair with axonal regrowth. This plasticity mechanism involves an atypical VPAC2 receptor and BDNF production. Stable VIP agonists mimic VIP effects when given systemically and exhibit a large therapeutic window. Unraveling cellular and molecular targets of VIP effects against perinatal white matter lesions could provide a more general rationale to understand the neuroprotection of the developing white matter against excitotoxic insults.

NAP prevents acute cerebral oxidative stress and protects against long-term brain injury and cognitive impairment in a model of neonatal hypoxia-ischemia

Hypoxia-ischemia (HI) is a common cause of neonatal brain damage with lifelong morbidities in which current therapies are limited. In this study, we investigated the effect of neuropeptide NAP (NAPVSIPQ) on early cerebral oxidative stress, long-term neurological function and brain injury after neonatal HI. Seven-day-old rat pups were subjected to an HI model by applying a unilateral carotid artery occlusion and systemic hypoxia. The animals were randomly assigned to groups receiving an intraperitoneal injection of NAP (3 μg/g) or vehicle immediately (0 h) and 24 h after HI. Brain DNA damage, lipid peroxidation and reduced glutathione (GSH) content were determined 24 h after the last NAP injection. Cognitive impairment was assessed on postnatal day 60 using the spatial version of the Morris water maze learning task. Next, the animals were euthanized to assess the cerebral hemispheric volume using the Cavalieri principle associated with the counting point method. We observed that NAP prevented the acute HI-induced DNA and lipid membrane damage and also recovered the GSH levels in the injured hemisphere of the HI rat pups. Further, NAP was able to prevent impairments in learning and long-term spatial memory and to significantly reduce brain damage up to 7 weeks following the neonatal HI injury. Our findings demonstrate that NAP confers potent neuroprotection from acute brain oxidative stress, long-term cognitive impairment and brain lesions induced by neonatal HI through, at least in part, the modulation of the glutathione-mediated antioxidant system.

Activity-dependent neuroprotective protein (ADNP)-derived peptide (NAP) ameliorates hypobaric hypoxia induced oxidative stress in rat brain

Hypobaric hypoxia is a socio-economic problem affecting cognitive, memory and behavior functions. Severe oxidative stress caused by hypobaric hypoxia adversely affects brain areas like cortex, hippocampus, basal ganglia, and cerebellum. In the present study, we have investigated the antioxidant and memory protection efficacy of the synthetic NAP peptide (NAPVSIPQ) during long-term chronic hypobaric hypoxia (7, 14, 21 and 28 days, 25,000ft) in rats. Intranasal supplementation of NAP peptide (2μg/Kg body weight) improved antioxidant status of brain evaluated by biochemical assays for free radical estimation, lipid peroxidation, GSH and GSSG level. Analysis of expression levels of SOD revealed that NAP significantly activated antioxidant genes as compared to hypoxia exposed rats. We have also observed a significant increased expression of Nrf2, the master regulator of antioxidant defense system and its downstream targets such as HO-1, GST and SOD1 by NAP supplementation, suggesting activation of Nrf2-mediated antioxidant defense response. In corroboration, our results also demonstrate that NAP supplementation improved the memory function assessed with radial arm maze. These cumulative results suggest the therapeutic potential of NAP peptide for ameliorating hypobaric hypoxia-induced oxidative stress.

Neuroprotective effects of NAP against excitotoxic brain damage in the newborn mice: implications for cerebral palsy

Activity-dependent neuroprotective protein (ADNP) was shown to be essential for embryogenesis and brain development while NAP, an active motif of ADNP, is neuroprotective in a broad range of neurodegenerative disorders. In the present study, we examined the protective potential of ADNP/NAP in a mouse model of excitotoxic brain lesion mimicking brain damage associated with cerebral palsy. We demonstrated that NAP had a potent neuroprotective effect against ibotenate-induced excitotoxic damage in the cortical plate and the white matter of P5 mice, and moderate against brain lesions of P0 mice. In contrast, endogenous ADNP appears not to be involved in the response to excitotoxic challenge in the studied model. Our findings further show that NAP reduced the number of apoptotic neurons through activation of PI-3K/Akt pathway in the cortical plate or both PI-3K/Akt and MAPK/MEK1 kinases in the white matter. In addition, NAP prevented ibotenate-induced loss of pre-oligodendrocytes without affecting the number of astrocytes or activated microglia around the site of injection. These findings indicate that protective actions of NAP are mediated by triggering transduction pathways that are crucial for neuronal and oligodendroglial survival, thus, NAP might be a promising therapeutic agent for treating developing brain damage.

Zinc and glutamine improve brain development in suckling mice subjected to early postnatal malnutrition

OBJECTIVE

The effect of zinc and glutamine on brain development was investigated during the lactation period in Swiss mice.

METHODS

Malnutrition was induced by clustering the litter size from 6-7 pups/dam (nourished control) to 12-14 pups/dam (undernourished control) following birth. Undernourished groups received daily supplementation with glutamine by subcutaneous injections starting at day 2 and continuing until day 14. Glutamine (100 mM, 40-80 microL) was used for morphological and behavioral studies. Zinc acetate was added in the drinking water (500 mg/L) to the lactating dams. Synaptophysin and myelin basic protein brain expressions were evaluated by immunoblot. Zinc serum and brain levels and hippocampal neurotransmitters were also evaluated.

RESULTS

Zinc with or without glutamine improved weight gain as compared to untreated, undernourished controls. In addition, zinc supplementation improved cliff avoidance and head position during swim behaviors especially on days 9 and 10. Using design-based stereological methods, we found a significant increase in the volume of CA1 neuronal cells in undernourished control mice, which was not seen in mice receiving zinc or glutamine alone or in combination. Undernourished mice given glutamine showed increased CA1 layer volume as compared with the other groups, consistent with the trend toward increased number of neurons. Brain zinc levels were increased in the nourished and undernourished-glutamine treated mice as compared to the undernourished controls on day 7. Undernourished glutamine-treated mice showed increased hippocampal gamma-aminobutyric acid and synaptophysin levels on day 14.

CONCLUSION

We conclude that glutamine or zinc protects against malnutrition-induced brain developmental impairments.

NAP protects against cytochrome c release: inhibition of the initiation of apoptosis

NAPVSIPQ (NAP), an 8 amino acid peptide derived from activity-dependent neuroprotective protein (ADNP), provides neuroprotection through interaction with microtubules. Previous results have demonstrated NAP protection against oxygen-glucose deprivation in hippocampal cells in culture. Furthermore, in vivo studies have shown that NAP reduces caspase 3 activation in rats subjected to permanent mid-cerebral artery occlusion (a rat model of stroke). Oxygen-glucose deprivation (ischemia) has been associated with microtubule breakdown and cytochrome c release from mitochondria leading to apoptosis. Here, NAP in concentrations ranging from 10(-14)M to 10(-8)M completely blocked cytochrome c release in cortical neurons subjected to oxygen-glucose deprivation. Furthermore, quantitative microscopy coupled to microtubule immunocytochemistry suggested that NAP prevented microtubule degradation under oxidative stress. As cytochrome c release is a known initiator of the apoptotic pathway, it is suggested that NAP inhibits the early events of apoptosis.

NAP and D-SAL: neuroprotection against the beta amyloid peptide (1-42)

Introduction

NAP (Asn-Ala-Pro-Val-Ser-Ile-Pro-Gln, single amino acid letter code, NAPVSIPQ), an eight amino acid neuroprotective peptide derived from activity-dependent neuroprotective protein (ADNP), exhibits some structural similarity to activity-dependent neurotropic factor-9 (ADNF-9; Ser-Alal-Leu-Leu-Arg-Ser-Ile-Pro-Ala, SALLRSIPA). Both peptides are also active in the all D-amino acid conformation, termed D-NAP and D-SAL. Original results utilizing affinity chromatography coupled to mass spectrometry identified tubulin, the subunit protein of microtubules, as the major NAP-associating protein in brain. The NAP-tubulin association was found to be diminished in the presence of ADNF-9, D-NAP, and D-SAL, suggesting a common target of neuroprotection. The β amyloid peptide interacts with microtubules, and previous studies have demonstrated protection against β amyloid (25–35) toxicity by NAP and ADNF-9. NAP also inhibits β amyloid (25–35 and 1–40) aggregation.

Methods

Cerebral cortical cultures derived from newborn rats were used in neuronal survival assays to test the activity of both NAP and D-SAL against the major Alzheimer's disease toxic peptide β amyloid (1–42).

Results

NAP and D-SAL protected cerebral cortical neurons against the major Alzheimer's disease toxic peptide β amyloid (1–42). Maximal protection of both peptides was observed at concentrations of 10^-15 to 10^-10 mol/l.

Conclusion

These findings, together with those of previous in vivo studies conducted in relevant Alzheimer's disease models, pave the path to drug development. Bioavailability studies indicated that NAP penetrates cells and crosses the blood-brain barrier after nasal or systemic administration. Phase II clinical trials of NAP are currently in progress by Allon Therapeutics Inc.

NAP protects hippocampal neurons against multiple toxins

The femtomolar-acting protective peptide NAP (NAPVSIPQ), derived from activity-dependent neuroprotective protein (ADNP), is broadly neuroprotective in vivo and in vitro in cerebral cortical cultures and a variety of cell lines. In the present study, we have extended previous results and examined the protective potential of NAP in primary rat hippocampal cultures, using microtubule-associated protein 2 (MAP2) as a measure for neuroprotection. Results showed that NAP, at femtomolar concentrations, completely protected against oxygen-glucose deprivation, and cyanide poisoning. Furthermore, NAP partially protected against kainic acid excitotoxicity. In summary, we have significantly expanded previous findings in demonstrating here direct neuroprotective effects for NAP on vital hippocampal neurons that are key participants in cognitive function in vivo.

Activity-dependent neuroprotective protein: from gene to drug candidate

Activity-dependent neuroprotective protein (ADNP) is essential for brain formation. The gene encoding ADNP is highly conserved and abundantly expressed in the brain. ADNP contains a homeobox profile and a peptide motif providing neuroprotection against a variety of cytotoxic insults. ADNP mRNA and protein expression responds to brain injury and oscillates as a function of the estrus cycle. The plastic nature of ADNP expression is correlated with brain protection and an association between neuroendocrine regulation and neuroprotection is put forth with ADNP as a focal point. Further understanding of neuroprotective molecules should pave the path to better diagnostics and therapies. In this respect, structure-activity studies have identified a short 8 amino acid peptide in ADNP/NAPVSIPQ (NAP) that provides potent neuroprotection. NAP is currently in clinical development for neuroprotection.