Complete sequence of a novel protein containing a femtomolar-activity-dependent neuroprotective peptide

The vulnerability of neurons and the irreversibility of loss make discoveries of neuroprotective compounds fundamentally important. Here, the complete coding sequence of a novel protein (828 amino acids, pI 5.99), derived from mouse neuroglial cells, is revealed. The sequence contained (1) a neuroprotective peptide, NAPVSIPQ, sharing structural and immunological homologies with the previously reported, activity-dependent neurotrophic factor; (2) a glutaredoxin active site; and (3) a zinc binding domain. Gene expression was enriched in the mouse hippocampus and cerebellum and augmented in the presence of the neuropeptide vasoactive intestinal peptide, in cerebral cortical astrocytes. In mixed neuron-astrocyte cultures, NAPVSIPQ provided neuroprotection at subfemtomolar concentrations against toxicity associated with tetrodotoxin (electrical blockade), the beta-amyloid peptide (the Alzheimer's disease neurotoxin), N-methyl-D-aspartate (excitotoxicity), and the human immunodeficiency virus envelope protein. Daily NAPVSIPQ injections to newborn apolipoprotein E-deficient mice accelerated the acquisition of developmental reflexes and prevented short-term memory deficits. Comparative studies suggested that NAPVSIPQ was more efficacious than other neuroprotective peptides in the apolipoprotein E-deficiency model. A potential basis for rational drug design against neurodegeneration is suggested with NAPVSIPQ as a lead compound. The relative enrichment of the novel mRNA transcripts in the brain and the increases found in the presence of vasoactive intestinal peptide, an established neuroprotective substance, imply a role for the cloned protein in neuronal function.

Growth factor function of vasoactive intestinal peptide in whole cultured mouse embryos

Factors controlling central nervous system (CNS) growth immediately after neurulation are mostly unknown. Vasoactive intestinal peptide (VIP) receptors are widely distributed in the embryonic nervous system, and VIP has trophic and mitogenic properties on embryonic neural tissues but inhibits growth and mitosis in certain tumours. To address the potential effects of VIP on embryonic growth, we used whole postimplantation embryo cultures. After a 4-h incubation, VIP stimulated growth, increasing somite number, embryonic volume, DNA and protein content, and number of cells in S-phase. A VIP antagonist substantially inhibited these VIP-mediated increments in growth. The VIP antagonist completely suppressed VIP-stimulated mitosis in the CNS while decreasing the same in non-neuronal tissues by 38%. In vitro autoradiography revealed GTP-sensitive and GTP-insensitive VIP receptors which were differentially regulated in VIP antagonist-treated embryos. The present study suggests that VIP acts as a growth factor on early postimplantation embryos through multiple VIP receptors that exhibit tissue-specific responses.

A femtomolar-acting neuroprotective peptide

A novel 14-amino acid peptide, with stress-protein-like sequences, exhibiting neuroprotection at unprecedented concentrations, is revealed. This peptide prevented neuronal cell death associated with the envelope protein (GP 120) from HIV, with excitotoxicity (N-methyl d-aspartate), with the beta amyloid peptide (putative cytotoxin in Alzheimer's disease), and with tetrodotoxin (electrical blockade). The peptide was designed to contain a sequence derived from a new neuroprotective protein secreted by astroglial cells in the presence of vasoactive intestinal peptide. The neurotrophic protein was isolated by sequential chromatographic methods combining ion exchange, size separation, and hydrophobic interaction. The protein (mol mass, 14 kD and pI, 8.3 +/- 0.25) was named activity-dependent neurotrophic factor, as it protected neurons from death associated with electrical blockade. Peptide sequencing led to the synthesis of the novel 14-amino acid peptide that was homologous, but not identical, to an intracellular stress protein, heat shock protein 60. Neutralizing antiserum to heat shock protein 60 produced neuronal cell death that could be prevented by cotreatment with the novel protein, suggesting the existence of extracellular stress-like proteins with neuroprotective properties. These studies identify a potent neuroprotective glial protein and an active peptide that provide a basis for developing treatments of currently intractable neurodegenerative diseases.

VIP: molecular biology and neurobiological function

In the mammalian brain, a major regulatory peptide is vasoactive intestinal peptide (VIP). This 28 amino acid peptide, originally isolated from the porcine duodenum, was later found in the central and peripheral nervous systems and in endocrine cells, where it exhibits neurotransmitter and hormonal roles. Increasing evidence points to VIP's importance as a mediator or a modulator of several basic functions. Thus, VIP is a major factor in brain activity, neuroendocrine functions, cardiac activity, respiration, digestion, and sexual potency. In view of this peptide's importance, the mechanisms controlling its production and the pathways regulating its functions have been reviewed. VIP is a member of a peptide family, including peptides such as glucagon, secretin, and growth hormone releasing hormone. These peptides may have evolved by exon duplication coupled with gene duplication. The human VIP gene contains seven exons, each encoding a distinct functional domain on the protein precursor or the mRNA. VIP gene transcripts are mainly found in neurons or neuron-related cells. VIP gene expression is regulated by neuronal and endocrine signals that contribute to its developmental control. VIP exerts its function via receptor-mediated systems, activating signal transduction pathways, including cAMP. It can act as a neurotransmitter, neuromodulator, and a secretagog. As a growth and developmental regulator, VIP may have a crucial effect as a neuronal survival factor. We shall proceed from the gene to its multiple functions.

Cloning and characterization of the human activity-dependent neuroprotective protein

We have recently cloned the mouse activity-dependent neuroprotective protein (ADNP). Here, we disclose the cloning of human ADNP (hADNP) from a fetal brain cDNA library. Comparative sequence analysis of these two ADNP orthologs indicated 90% identity at the mRNA level. Several single nucleotide polymorphic sites were noticed. The deduced protein structure contained nine zinc fingers, a proline-rich region, a nuclear bipartite localization signal, and a homeobox domain profile, suggesting a transcription factor function. Further comparative analysis identified an ADNP paralog (33% identity and 46% similarity), indicating that these genes belong to a novel protein family with a nine-zinc finger motif followed by a homeobox domain. The hADNP gene structure spans approximately 40 kilobases and includes five exons and four introns with alternative splicing of an untranslated second exon. The hADNP gene was mapped to chromosome 20q12-13.2, a region associated with aggressive tumor growth, frequently amplified in many neoplasias, including breast, bladder, ovarian, pancreatic, and colon cancers. hADNP mRNA is abundantly expressed in distinct normal tissues, and high expression levels were encountered in malignant cells. Down-regulation of ADNP by antisense oligodeoxynucleotides up-regulated the tumor suppressor p53 and reduced the viability of intestinal cancer cells by 90%. Thus, ADNP is implicated in maintaining cell survival, perhaps through modulation of p53.

Cytokine regulation of neuronal survival

Interleukin-1 is a cytokine involved in the immune response to infection and inflammation as well as a growth promotor for several cell types. Interleukin-1-like immunoreactive material has been found in the nervous system. We now show that antisera, which blocked the T-cell proliferative effects of interleukin-1 alpha, decreased neuronal cell counts (to 40% of control) in dissociated spinal cord cultures derived from fetal mice. This neuronal loss was prevented by addition of interleukin-1 alpha, and to a lesser extent by interleukin-1 beta. Exogenous interleukin-1 alpha increased the survival of neurons when added to cultures in which the electrical activity was blocked with tetrodotoxin, whereas no such cytokine-related increase in neuronal survival was observed in electrically active cultures. The antiserum-induced death could also be prevented by cotreatment of the cultures with 0.1 nM vasoactive intestinal peptide, a substance that induces the secretion of neuronal trophic factors from nonneuronal spinal cord cells and thereby increases neuronal survival in electrically inactive cultures. These studies indicate that the cytokine interleukin-1, or an immunologically cross-reactive protein, can increase neuronal survival.

Autophagy has a key role in the pathophysiology of schizophrenia

Autophagy is a process preserving the balance between synthesis, degradation and recycling of cellular components and is therefore essential for neuronal survival and function. Several key proteins govern the autophagy pathway including beclin1 and microtubule associated protein 1 light chain 3 (LC3). Here, we show a brain-specific reduction in beclin1 expression in postmortem hippocampus of schizophrenia patients, not detected in peripheral lymphocytes. This is in contrast with activity-dependent neuroprotective protein (ADNP) and ADNP2, which we have previously found to be deregulated in postmortem hippocampal samples from schizophrenia patients, but that now showed a significantly increased expression in lymphocytes from related patients, similar to increases in the anti-apoptotic, beclin1-interacting, Bcl2. The increase in ADNP was associated with the initial stages of the disease, possibly reflecting a compensatory effect. The increase in ADNP2 might be a consequence of neuroleptic treatment, as seen in rats subjected to clozapine treatment. ADNP haploinsufficiency in mice, which results in age-related neuronal death, cognitive and social dysfunction, exhibited reduced hippocampal beclin1 and increased Bcl2 expression (mimicking schizophrenia and normal human aging). At the protein level, ADNP co-immunoprecipitated with LC3B suggesting a direct association with the autophagy process and paving the path to novel targets for drug design.

Vasoactive intestinal peptide prevents excitotoxic cell death in the murine developing brain

Excitotoxic damage may be a critical factor in the formation of brain lesions associated with cerebral palsy. When injected at birth, the glutamatergic analog ibotenate induces mouse brain lesions that strikingly mimic human microgyria. When ibotenate is injected at postnatal day 5, it produces transcortical necrosis and white matter cysts that mimic human perinatal hypoxic-like lesions. Vasoactive intestinal peptide (VIP) has potent growth-related actions and neuroprotective properties that influence mitosis and neuronal survival in culture. The goal of this study was to assess the protective role of VIP against excitotoxic lesions induced by ibotenate in developing mouse brain. VIP cotreatment reduced ibotenate-induced microgyric-like cortical lesions and white matter cysts by up to 77 and 85%, respectively. VIP protective effects were reproduced by a peptide derived from activity-dependent neurotrophic factor (ADNF), a trophic factor released by VIP-stimulated astrocytes, and by stearyl norleucine VIP, a specific VIP agonist that does not activate adenylate cyclase. Neither forskolin, an adenylate cyclase activator, nor pituitary adenylate cyclase-activating peptide, provided VIP-like protection. VIP and neurotrophic analogs, acting through a cAMP-independent mechanism and inducing ADNF release, could represent new avenues in the understanding and prevention of human cerebral palsy.

Vasoactive intestinal peptide and pituitary adenylate cyclase-activating polypeptide inhibit tumor necrosis factor alpha transcriptional activation by regulating nuclear factor-kB and cAMP response element-binding protein/c-Jun

Tumor necrosis factor alpha (TNFalpha), an early cytokine produced by activated macrophages, plays an essential role in normal and pathological inflammatory reactions. The excessive production of TNFalpha is prevented by the so-called "macrophage-deactivating factors." This study examines the role of two structurally related neuropeptides, the vasoactive intestinal peptide (VIP) and the pituitary adenylate cyclase-activating peptide (PACAP), as inhibitors of TNFalpha. Both VIP and PACAP inhibit TNFalpha production from lipopolysaccharide-stimulated RAW 246.7 cells in a dose- and time-dependent manner. Although the activated cells express mRNA for all three VIP/PACAP receptors, agonist and antagonist studies indicate that the major receptor involved is VIP1R. VIP/PACAP inhibit TNFalpha gene expression by affecting both NF-kB binding and the composition of the cAMP responsive element binding complex (CREB/c-Jun). Two transduction pathways, a cAMP-dependent and a cAMP-independent pathway, are involved in the inhibition of TNFalpha gene expression and appear to differentially regulate the transcriptional factors involved. Because TNFalpha plays a central role in various inflammatory diseases such as endotoxic shock, multiple sclerosis, cerebral malaria, and various autoimmune conditions, the down-regulatory effect of VIP/PACAP may have a significant therapeutic potential.

Neuroprotective strategy for Alzheimer disease: intranasal administration of a fatty neuropeptide

Neurodegenerative diseases, in which neuronal cell disintegrate, bring about deteriorations in cognitive functions as is evidenced in millions of Alzheimer patients. A major neuropeptide, vasoactive intestinal peptide (VIP), has been shown to be neuroprotective and to play an important role in the acquisition of learning and memory. A potent lipophilic analogue to VIP now has been synthesized, [stearyl-norleucine17]VIP ([St-Nle17]VIP), that exhibited neuroprotection in model systems related to Alzheimer disease. The beta-amyloid peptide is a major component of the cerebral amyloid plaque in Alzheimer disease and has been shown to be neurotoxic. We have found a 70% loss in the number of neurons in rat cerebral cortical cultures treated with the beta-amyloid peptide (amino acids 25-35) in comparison to controls. This cell death was completely prevented by cotreatment with 0.1 pM [St-Nle17]VIP. Furthermore, characteristic deficiencies in Alzheimer disease result from death of cholinergic neurons. Rats treated with a cholinergic blocker (ethylcholine aziridium) have been used as a model for cholinergic deficits. St-Nle-VIP injected intracerebroventricularly or delivered intranasally prevented impairments in spatial learning and memory associated with cholinergic blockade. These studies suggest both an unusual therapeutic strategy for treatment of Alzheimer deficiencies and a means for noninvasive peptide administration to the brain.

Tubulin: an integral protein of mammalian synaptic vesicle membranes

The major protein in isolated synaptic vesicles from bovine cerebral cortex has been compared to tubulin by sodium dodecyl sulphate-urea polyacrylamide gel electrophoresis, by two-dimensional gel electrophoresis, and by peptide mapping following limited proteolysis of the protein by Staphylococcus aureus protease. The results establish in purified synaptic vesicles the presence of tubulin, which is composed of the alpha and beta subunits. In the presence of ethyleneglycolbis)aminoethyl ether)-N,N'-tetraacetic acid (EGTA) or magnesium in the isolation buffers, the synaptic vesicles contained mainly the alpha-tubulin whereas the beta subunit was less abundant. Similarly, synaptosomal plasma membranes that were prepared in the presence of EGTA also contained more of alpha-tubulin than of the beta subunit. Non-ionic detergents such as Triton X-100 or Nonidet P-40 failed to solubilize the tubulin from the synaptic vesicles. Ionic detergents such as deoxycholate and sodium dodecyl sulphate solubilized all the vesicle proteins, including tubulin. The results indicate that alpha-tubulin is an integral vesicle membrane protein, whereas most of the beta subunit is peripherally attached and can be easily dissociated from the vesicle membrane with EGTA.

Learning impairment following intracerebral administration of the HIV envelope protein gp120 or a VIP antagonist

The external envelope glycoprotein (gp120) of the human immunodeficiency virus (HIV) has been shown to be toxic to neurons in culture. To further investigate the neurological effects of gp120, the involvement of this protein with the acquisition of spatial discrimination was assessed. Both native and recombinant gp120 were administered into the cerebral ventricles of adult rats and performance was evaluated in the Morris swim maze. Gp120 treatment retarded acquisition after daily administration of 12 ng. The specificity of this impairment was demonstrated in that the performance of animals given the same amount of gp160 from recombinant baculovirus was not different from animals given saline. Vasoactive intestinal peptide (VIP) has been shown to block gp120-induced neurotoxicity in culture and a VIP receptor antagonist has displayed toxic properties to neurons in culture. We show here that this antagonist, which competitively inhibits VIP binding and blocks VIP-mediated functions in cell cultures from the CNS, also produced an impairment of performance. This retardation was attenuated by cotreatment with VIP, supporting the specificity of the observed impairment. Thus, gp120 and the VIP antagonist produced similar retardation of spatial discrimination, suggesting that both may impair memory for spatially related stimulus control.

Vasoactive intestinal peptide (VIP) prevents neurotoxicity in neuronal cultures: relevance to neuroprotection in Parkinson's disease

Vasoactive intestinal peptide (VIP) provides neuroprotection against beta-amyloid toxicity in models of Alzheimer's disease. A superactive analogue, stearyl-Nle17-VIP (SNV) is a 100-fold more potent than VIP. In primary neuronal cultures, VIP protective activity may be mediated by femtomolar-acting glial proteins such as activity-dependent neurotrophic factor (ADNF), activity-dependent neuroprotective protein (ADNP), peptide derivatives ADNF-9 (9aa) and NAP (8aa), respectively. It has been hypothesized that beta-amyloid induces oxidative stress leading to neuronal cell death. Similarly, dopamine and its oxidation products were suggested to trigger dopaminergic nigral cell death in Parkinson's disease. We now examined the possible protective effects of VIP against toxicity of dopamine, 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpyridinium ion (MPP+) in neuronal cultures [rat pheochromocytoma (PC12), human neuroblastoma (SH-SY5Y) and rat cerebellar granular cells]. Remarkably low concentrations of VIP (10(-16)-10(-8) M), ADNF-9 and NAP (10(-18)-10(-10) M) protected against dopamine and 6-OHDA toxicity in PC12 and neuroblastoma cells. VIP (10(-11)-10(-9) M) and SNV (10(-13)-10(-11) M), protected cerebellar granule neurons against 6-OHDA. In contrast, VIP did not rescue neurons from death associated with MPP+. Since dopamine toxicity is linked to the red/ ox state of the cellular glutathione, we investigated neuroprotection in cells depleted of reduced glutathione (GSH). Buthionine sulfoximine (BSO), a selective inhibitor of glutathione synthesis, caused a marked reduction in GSH in neuroblastoma cells and their viability decreased by 70-90%. VIP, SNV or NAP (over a wide concentration range) provided significant neuroprotection against BSO toxicity. These results show that the mechanism of neuroprotection by VIP/SNV/NAP may be mediated through raising cellular resistance against oxidative stress. Our data suggest these compounds as potential lead compounds for protective therapies against Parkinson's disease.

Decrease in levels and rates of synthesis of tubulin and actin in developing rat brain

The cytoplasmic and particulate tubulin content of postnatal rat brains was determined at various stages of development. The amount of tubulin in the soluble fraction was found to increase after birth and levels off at the age of 10-15 days, while the total protein content is still increasing. Indeed, the percentage of tubulin in the soluble fraction is about 33% at birth, stays at this value until day 10, and then decreases to 20% between days 10 and 15. On the other hand, the rate of increase in the level of the particulate tubulin parallels that of the total particulate proteins, and hence there is no change in the percentage of particulate tubulin during brain development. There was close agreement between the tubulin values obtained by the [3H]-colchicine binding assay and those obtained by electrophoretic resolution in sodium dodecylsulfate-polyacrylamide gels. Polyacrylamide gel electrophoresis was also utilized to determine actin levels in developing brains. The percentage of cytoplasmic brain actin also decreased with the age of the rats, from a value of 20% at birth to 10% at day 30, while the percentage of the particulate actin remained constant. The decline in the percentage of cytoplasmic tubulin and actin during brain development can be accounted for by reduction in the proportions of the respective mRNA species. Translation of poly (A)-rich brain mRNA in a wheat-germ cell-free system showed that the percentages of tubulin and actin synthesized decreased gradually with age. Similar results were obtained by analyzing the proteins produced by isolated brain polysomes in a brain cell-free system.

Severe microcephaly induced by blockade of vasoactive intestinal peptide function in the primitive neuroepithelium of the mouse

Vasoactive intestinal peptide (VIP) has potent growth-related actions that influence cell mitosis, neuronal survival, and neurodifferentiation in cell culture. VIP can also produce dramatic growth in postimplantation mouse embryos in vitro, characterized by large increases in cell number. The goal of the present study was to assess the role of VIP on early nervous system development in vivo. Pregnant mice were treated with a specific antagonist to VIP. Prenatal administration of the antagonist early in development (E9-E11) produced severe microcephaly characterized by decreased embryonic brain weight with reduced DNA and protein content. The retardation of growth was disproportionally manifested in the brain compared with the body and was prevented by co-treatment with VIP. Identical treatment with the antagonist later in gestation had no detectable effect on embryonic growth. VIP receptors, which were restricted to the central nervous system during this stage of embryonic development, were increased in the neuroepithelium of antagonist-treated embryos while the number of cells in S-phase was significantly decreased. Thus, VIP regulates brain growth in vivo and inhibition of its action provides new insight into a molecular mechanism for microcephaly.

A vasoactive intestinal peptide antagonist inhibits non-small cell lung cancer growth

The most prevalent lung cancer, non-small cell lung cancer (NSCLC) has receptors for vasoactive intestinal peptide (VIP). Here the effects of a VIP antagonist (VIP-hyb) on NSCLC growth were investigated. In vivo, when VIPhyb (10 micrograms, s.c.) was daily injected into nude mice, xenograft formation was significantly inhibited by approximately 80%. In vitro, VIP (100 nM) stimulated colony formation approximately 2-fold, whereas 1 microM VIPhyb inhibited colony formation by approximately 50% when adenocarcinoma cell line NCI-H838 was used. The attenuation of tumor proliferation is receptor mediated, as VIPhyb inhibited specific 125I-labeled VIP binding to cell lines NCI-H157 and NCI-H838 with an IC50 of 0.7 microM. VIP (10 nM) increased the cAMP levels 5-fold when cell line NCI-H838 was used, and 10 microM VIPhyb inhibited the increase in cAMP caused by VIP. Northern blot analysis and radioimmunoassays have shown VIP mRNA and VIP-like immunoreactivity in NSCLC cells. These data suggest that VIP may be a regulatory peptide in NSCLC and that VIPhyb is a VIP receptor antagonist that inhibits proliferation.

Localization of vasopressin-, vasoactive intestinal polypeptide-, peptide histidine isoleucine- and somatostatin-mRNA in rat suprachiasmatic nucleus

Messenger RNAs (mRNA) coding for vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), somatostatin and vasopressin were localized in the suprachiasmatic nucleus (SCN) of the rat hypothalamus using in situ hybridization histochemistry. Specific mRNA coding for each of these peptides was distributed in areas coextensive with the immunohistochemical localization of the appropriate peptide. The autoradiographic signal produced with probes to VIP and PHI created dense concentrations of silver grains over neuronal perikarya in the ventrolateral SCN, and the coextensive distribution of both VIP- and PHI-mRNAs suggests that both peptides are synthesized within the same neurons. The distribution of somatostatin-mRNA was distinct from the of VIP and PHI. Labeled neurons are observed at the interface of the two SCN subdivisions and the distribution of these neurons is identical to those shown to contain somatostatin immunoreactivity. Vasopressin-mRNA is also differentially concentrated within neurons in the dorsomedial subdivision of the SCN in an area that is coextensive with vasopressin-immunoreactive perikarya. The discrete pattern of hybridization for each of these mRNAs indicates that each of these peptides are synthesized in SCN neurons and reaffirms the differential distribution of each of these chemically defined cell populations within cytoarchitecturally distinct subdivisions of the nucleus.

Experimental intrauterine growth retardation alters renal development

Vascular placental insufficiency is considered a common pathogenic factor in human intrauterine growth retardation (IUGR), resulting in small-for-gestational-age, asymmetric newborns. IUGR neonates experience higher morbidity and mortality rates, as well as a possible contribution towards late sequelae, such as hypertension, and cardiovascular disease in adulthood. To simulate vascular placental insufficiency, an experimental rabbit IUGR model was used. Intrauterine growth retardation was achieved by ligation of 25-30% uteroplacental vessels of half of the fetuses during the last third of gestation. Ischemic fetuses were significantly small, asymmetric, and had a disproportionately small body with a relatively large head. The kidneys from all groups were analyzed for relative estimated glomeruli number (REGN) using an unbiased blind design. The glomeruli number was significantly reduced in the asymmetric IUGR rabbit fetuses, probably due to decreased renal vascular supply. Our results support the concept that the reduced number of glomeruli may contribute to impaired renal function, thus predisposing to neonatal renal dysfunction and late sequelae, such as adult hypertension. This study emphasizes the clinical importance of early IUGR diagnosis and prevention.

Vasoactive intestinal peptide potentiates sexual behavior: inhibition by novel antagonist

Vasoactive intestinal peptide (VIP) has been suggested as a neurotransmitter mediating penile erection. We now show that VIP can stimulate sexual behavior in rats with reduced masculine potential due to pituitary grafting or castration. This effect was attenuated in the presence of a novel VIP antagonist, devised by a hybrid peptide strategy. Thus, we have synthesized a molecule combining a portion of VIP with a portion of neurotensin, peptides of opposite pharmacological action on cAMP formation and smooth muscle relaxation. The hybrid peptide markedly inhibited VIP's effect on sexual behavior. This inhibition was manifested by a significant increase in the mean interval between copulatory events (greater than 3-fold change) coupled with a blockade of VIP-stimulated ejaculation. Other putative VIP antagonists were not as effective in blocking these activities. Thus, our results imply that VIP is not only associated with penile erection, but is involved in sexual behavior as well. Furthermore, the hybrid antagonist was shown to inhibit VIP binding in glial cell cultures. The availability of highly potent VIP antagonists may offer a route to study the possible multiple VIP receptors as well as help delineate other biological activities attributable to VIP.

SIRT1, miR-132 and miR-212 link human longevity to Alzheimer's Disease

Alzheimer's Disease (AD) is the most common cause of dementia in the elderly. Centenarians - reaching the age of >100 years while maintaining good cognitive skills - seemingly have unique biological features allowing healthy aging and protection from dementia. Here, we studied the expression of SIRT1 along with miR-132 and miR-212, two microRNAs known to regulate SIRT1, in lymphoblastoid cell lines (LCLs) from 45 healthy donors aged 21 to 105 years and 24 AD patients, and in postmortem olfactory bulb and hippocampus tissues from 14 AD patients and 20 age-matched non-demented individuals. We observed 4.0-fold (P = 0.001) lower expression of SIRT1, and correspondingly higher expression of miR-132 (1.7-fold; P = 0.014) and miR-212 (2.1-fold; P = 0.036), in LCLs from AD patients compared with age-matched healthy controls. Additionally, SIRT1 expression was 2.2-fold (P = 0.001) higher in centenarian LCLs compared with LCLs from individuals aged 56-82 years; while centenarian LCLs miR-132 and miR-212 indicated 7.6-fold and 4.1-fold lower expression, respectively. Correlations of SIRT1, miR-132 and miR-212 expression with cognitive scores were observed for AD patient-derived LCLs and postmortem AD olfactory bulb and hippocampus tissues, suggesting that higher SIRT1 expression, possibly mediated by lower miR-132 and miR-212, may protect aged individuals from dementia and is reflected in their peripheral tissues.

Monoclonal antibodies that recognize discrete forms of tubulin

Anti-tubulin antibodies secreted by plasmacytoma NSI-spleen cell hybrids were detected by an indirect binding assay. Different antibodies bound to different combinations of the tubulins as resolved by isoelectric focusing. Two monoclonal antibodies (TUB 2.1 and TUB 2.5) labeled only (i) the tubulin band on a polyacrylamide electropherogram and (ii) beta-tubulins as resolved by isoelectric focusing. The fraction that was specifically bound and eluted from antibody affinity columns was enriched in beta-tubulins as compared with alpha-tubulins, suggesting the possibility of some soluble tubulin homodimers and alpha,beta-heterodimers. Double labeling experiments were used to show that all detectable microtubules contained beta-tubulin.

The rescue of microtubule-dependent traffic recovers mitochondrial function in Parkinson's disease

In Parkinson's disease mitochondrial dysfunction can lead to a deficient ATP supply to microtubule protein motors leading to mitochondrial axonal transport disruption. Compromised axonal transport will then lead to a disorganized distribution of mitochondria and other organelles in the cell, as well as, the accumulation of aggregated proteins like alpha-synuclein. Moreover, axonal transport disruption can trigger synaptic accumulation of autophagosomes packed with damaged mitochondria and protein aggregates promoting synaptic failure. We previously observed that neuronal-like cells with an inherent mitochondrial impairment derived from PD patients contain a disorganized microtubule network, as well as, alpha-synuclein oligomer accumulation. In this work we provide new evidence that an agent that promotes microtubule network assembly, NAP (davunetide), improves microtubule-dependent traffic, restores the autophagic flux and potentiates autophagosome-lysosome fusion leading to autophagic vacuole clearance in Parkinson's disease cells. Moreover, NAP is capable of efficiently reducing alpha-synuclein oligomer content and its sequestration by the mitochondria. Most interestingly, NAP decreases mitochondrial ubiquitination levels, as well as, increases mitochondrial membrane potential indicating a rescue in mitochondrial function. Overall, we demonstrate that by improving microtubule-mediated traffic, we can avoid mitochondrial-induced damage and thus recover cell homeostasis. These results prove that NAP may be a promising therapeutic lead candidate for neurodegenerative diseases that involve axonal transport failure and mitochondrial impairment as hallmarks, like Parkinson's disease and related disorders.

A new concept in the pharmacology of neuroprotection

Vasoactive intestinal peptide (VIP), originally discovered in the intestine as a peptide of 28 amino acids, was later found to be a major brain peptide having neuroprotective activities. To exert neuroprotective activity, VIP requires glial cells secreting neuroprotective proteins. Activity-dependent neurotrophic factor (ADNF) is a recently isolated factor secreted by glial cells under the action of VIP. This protein, isolated by sequential chromatographic methods, was named activity-dependent neurotrophic factor since it protected neurons from death associated with blockade of electrical activity. A fourteen-amino-acid fragment of ADNF (ADNF-14) and the more potent, nine-amino-acid derivative (ADNF-9), exhibit activity that surpasses that of the parent protein with regard to potency and a broader range of effective concentration. Furthermore, the peptides exhibit protective activity in Alzheimer's disease-related systems (e.g., beta-amyloid toxicity and apolipoprotein E deficiencies, genes that have been associated with Alzheimer's disease onset and progression). ADNP is another glial mediator of VIP-associated neuroprotection. NAP, an eight-amino-acid peptide derived from ADNP (sharing structural and functional similarities with ADNF-9), was identified as the most potent neuroprotectant described to-date in an animal model of apolipoprotein E-deficiency (knock-out mice). These femtomolar-acting peptides form a basis for a new concept in pharmacology: femtomolar neuroprotection.