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Douglas E Brenneman

Publications and source records attributed to Douglas E Brenneman.

At least 19 recordsLinked to original sources
PubMed2005

Sexual dimorphism of activity-dependent neuroprotective protein in the mouse arcuate nucleus.

Activity-dependent neuroprotective protein (ADNP) is a highly conserved vasoactive intestinal peptide (VIP) responsive gene that is expressed abundantly in the brain and in the body and is essential for brain formation and embryonic development. Since, VIP exhibits sexual dimorphism in the hypothalamus, the potential differential expression of ADNP in male and female mice was investigated. Real-time polymerase chain reaction revealed sexual dimorphism in ADNP mRNA expression as well as fluctuations within the estrus cycle. Immunohistochemistry with an antibody to ADNP showed specific staining in the arcuate nucleus of the hypothalamus. ADNP-like immunoreactivity in the arcuate nucleus also exhibited fluctuations during the estrus cycle. Here, brain sections at proestrus were the most immunoreactive and brain sections at estrus--the least. Furthermore, male arcuate nucleus ADNP-like immunoreactivity was significantly lower than that of the female estrus. Many neuropeptides, neurotransmitters and proteins are localized to the arcuate nucleus where they contribute to the regulation of reproductive cyclicity and energy homeostasis. The results presented here suggest that ADNP has a part in the estrus cycle as an affecter or an effector.

Animals↗
PubMed2005

Novel peptides prevent alcohol-induced spatial learning deficits and proinflammatory cytokine release in a mouse model of fetal alcohol syndrome.

OBJECTIVE: Previously, the novel peptides NAPVSIPQ and SALLRSIPA were shown to prevent alcohol-induced fetal death and growth abnormalities in a mouse model of fetal alcohol syndrome. This study evaluated whether these peptides could prevent long-term alcohol-induced learning abnormalities. In addition, because specific cytokines are known to effect long-term potentiation, a model of learning at the molecular level, we studied the effect of these novel peptides on tumor necrosis factor-alpha, interleukin-6, and interferon-gamma levels. STUDY DESIGN: We used a well-characterized mouse model of fetal alcohol syndrome. Pregnant mice were injected on day 8 with alcohol (0.03 mL/kg) or placebo. Pretreatment with NAPVSIPQ+SALLRSIPA (20 mug) or placebo was given 30 minutes before alcohol. Embryos were removed after 6 hours, at which time cytokine, tumor necrosis factor-alpha, interleukin-6, and interferon-gamma levels were measured with enzyme-linked immunoassays. To test spatial learning, adult offspring from litters that were treated with alcohol, control, NAPVSIPQ+SALLRSIPA then alcohol, or NAPVSIPQ+SALLRSIPA alone were evaluated for latency to find a hidden platform in the Morris water maze. RESULTS: Alcohol treatment increased tumor necrosis factor-alpha levels versus control levels (50.0 +/- 3.5 pg/mL vs 32.7 +/- 2.4 pg/mL; P < .001). NAPVSIPQ+SALLRSIPA pretreatment prevented this increase (39.9 9 +/- 2.8 pg/mL; P </= .01), with levels similar to control (P=.1). Similarly, alcohol increased interleukin-6 levels versus control levels (22.6 +/- 1.4 pg/mL vs 17.3 +/- 0.6 pg/mL; P < .001), and NAPVSIPQ+SALLRSIPA prevented this increase (19.1 +/- 1.0 pg/mL; P </= .02), with levels similar to control levels (P=.2). Interferon-gamma levels were not different among the 3 groups (alcohol, 14.6 +/- 4.9 pg/mL; control, 17.9 +/- 6.6 pg/mL; alcohol+NAPVSIPQ+SALLRSIPA, 13.6 +/- 4.9 pg/mL; P=.2). In the Morris water maze, alcohol-treated groups did not learn over the 7-day trial compared with the control group (P=.001). Groups that were pretreated with NAPVSIPQ+SALLRSIPA then alcohol learned significantly, which was similar to the control group. Groups that were treated with only NAPVSIPQ+SALLRSIPA learned significantly earlier, with the shortest latency once learning commenced. CONCLUSION: The peptides, NAPVSIPQ+SALLRSIPA, prevented the alcohol-induced spatial learning deficits and attenuated alcohol-induced proinflammatory cytokine increase in a model of fetal alcohol syndrome. This study demonstrates the peptides' significant in vivo efficacy with long-lasting effects obtained after prenatal administration.

Animals↗
PubMed2005

Activity-dependent neurotrophic factor-9 and NAP promote neurite outgrowth in rat hippocampal and cortical cultures.

Activity-dependent neurotrophic factor (ADNF) is a novel, femtomolar-acting, glial-derived polypeptide (14 kDa) known to protect neurons from a variety of toxic insults. The active site for ADNF function is localized to a 9-amino-acid stretch (SALLRSIPA; ADNF-9). A few years later, a novel ADNF-9-like active peptide (NAPVSIPQ or NAP) was identified and shown to be expressed in the CNS and exhibit an activity profile similar to ADNF-9. Such studies suggest that ADNF-9 and NAP might function like other known neurotrophins and play a role in neural development and maintenance. The purpose of the present studies was to determine if ADNF-9 or NAP affects neurite outgrowth and synaptogenesis in rat hippocampal and cortical cultures. Using MAP2-FITC immunofluorescent labeling, we found that ADNF-9 and NAP promoted neurite outgrowth in a concentration-dependent manner, with maximal activity observed at femtomolar concentrations. Both peptides stimulated robust outgrowth in hippocampal cells (approximately 150% of control; p < 0.01) with a modest effect on cortical cells (approximately 20% of control; p < 0.05) similar to other known growth factors. However, the outgrowth-promoting effect was abolished in the absence of serum, suggesting that soluble factors might be necessary for the neurotrophic activity. Finally, we found that ADNF-9 and NAP increased synaptophysin expression in both rat hippocampal and cortical cultures. These results suggest that ADNF-9 and NAP might contribute to neuronal plasticity associated with development and repair after injury.

Animals↗
PubMed2005

The expression of activity-dependent neuroprotective protein (ADNP) is regulated by brain damage and treatment of mice with the ADNP derived peptide, NAP, reduces the severity of traumatic head injury.

NAP is a short octapeptide sequence (single letter code, NAPVSIPQ) that protects neurons against a wide variety of insults. The NAP sequence was identified by peptide structure/function scanning of activity-dependent neuroprotective protein (ADNP), a gene product essential for brain formation. To further evaluate the in vivo efficacy of NAP neuroprotection we used a mouse model of head trauma; a condition that presents a risk factor for the development of Alzheimer's disease in injured patients. In the mouse model, NAP treatment (prophylactic or curative) indicated improvement in longitudinal clinical, biochemical and anatomical outcomes. Furthermore, closed head injury was associated with a delayed increase in the expression of the immune cell surface glycoprotein Mac-1 (CD11B antigen) at the injury site that was decreased in NAP-treated mice. Additional experiments with Mac-1-deficient mice suggested partial protection against death related to severe head injury. NAP protection in Mac-1-deficient mice against adverse clinical outcome was concomitant with the time period when increases in Mac-1 transcripts were observed in the Mac-1 expressing mice ( approximately four weeks after the injury). The expression of ADNP (the NAP parent protein) was also increased at the injured brain site four weeks after the traumatic event, only in Mac-1 expressing mice. Here, using immunocytochemistry, we localized the increase in ADNP to microglia and astrocyte-like cells. The increase in ADNP in injured brains is now suggested to be a part of an endogenous compensatory mechanism and NAP treatment provides an additional protection. Toxicology studies suggest NAP as safe for further clinical development.

Animals↗
PubMed2004

Protective peptides that are orally active and mechanistically nonchiral.

Previous reports identified two peptides that mimic the action of neuroprotective proteins derived from astrocytes. These peptides, NAPVSIPQ and SALLRSIPA, prevent neuronal cell death produced by electrical blockade, N-methyl-d-aspartate, and beta-amyloid peptide (25-35). In the present study, all d-amino acid peptides of NAPVSIPQ and SALLRSIPA were synthesized and compared respectively to the corresponding all l-amino acid peptides. In rat cerebral cortical test cultures cotreated with 1 microM tetrodotoxin, the d-amino acid peptides produced similar potency and efficacy for neuroprotection as that observed for their respective l-amino acid peptides. Since all these peptides tested individually exhibited attenuation of efficacy at concentrations of >10 pM, combinations of these peptides were tested for possible synergies. Equimolar d-NAPVSIPQ and d-SALLRSIPA combination treatment produced potent neuroprotection (EC(50), 0.03 fM) that did not attenuate with increasing concentrations. Similarly, the combination of l-NAPVSIPQ and d-SALLRSIPA also had high potency (EC(50), 0.07 fM) without attenuation of efficacy. Combined administration of peptides was tested in a model of fetal alcohol syndrome and in a model of learning impairment: apolipoprotein E knockout mice. Intraperitoneal administration of d-NAPVSIPQ plus d-SALLRSIPA to pregnant mice (embryonic day 8) attenuated fetal demise after treatment with an acute high dose of alcohol. Furthermore, oral administration of d-NAPVSIPQ plus d-SALLRSIPA significantly increased fetal survival after maternal alcohol treatment. Apolipoprotein E knockout mice injected with d-NAPVSIPQ plus d-SALLRSIPA showed improved performance in the Morris water maze. These studies suggest therapeutic potential for the combined administration of neuroprotective peptides that can act through a mechanism independent of chiral recognition.

Administration, Oral↗
PubMed2004

High-throughput siRNA-based functional target validation.

The drug discovery process pursued by major pharmaceutical companies for many years starts with target identification followed by high-throughput screening (HTS) with the goal of identifying lead compounds. To accomplish this goal, significant resources are invested into automation of the screening process or HTS. Robotic systems capable of handling thousands of data points per day are implemented across the pharmaceutical sector. Many of these systems are amenable to handling cell-based screening protocols as well. On the other hand, as companies strive to develop innovative products based on novel mechanisms of action(s), one of the current bottlenecks of the industry is the target validation process. Traditionally, bioinformatics and HTS groups operate separately at different stages of the drug discovery process. The authors describe the convergence and integration of HTS and bioinformatics to perform high-throughput target functional identification and validation. As an example of this approach, they initiated a project with a functional cell-based screen for a biological process of interest using libraries of small interfering RNA (siRNA) molecules. In this protocol, siRNAs function as potent gene-specific inhibitors. siRNA-mediated knockdown of the target genes is confirmed by TaqMan analysis, and genes with impacts on biological functions of interest are selected for further analysis. Once the genes are confirmed and further validated, they may be used for HTS to yield lead compounds.

Base Sequence↗
PubMed2004

Gene expression analysis for high throughput screening applications.

To meet growing needs for high throughput gene expression profiling, we established a new automated high throughput TaqMan RT-PCR method for quantitative mRNA expression analysis. In this method, the Allegro( trade mark ) (Zymark) system conducts all sample tracking and liquid handling steps, and ABI PRISM 7900 HT (Applied Biosystems) is used to conduct real-time determination of the C(t) value when amplification of PCR products is first detected and accumulation of inhibitory PCR products is unlikely to occur. The ABI PRISM 7900 HT Sequence Detection System features a real-time PCR instrument with 384-well-plate compatibility and robotic loading, and continuous wavelength detection, which enables the use of multiple fluorophores in a single reaction. The Allegro System offers an assembly line approach with a modular design that allows reconfiguration of the components to accommodate variations in the assay flow. In the present study, we have established and validated a new automated High Throughput (HT) TaqMan RT-PCR- based method for quantitative mRNA expression analysis. The data demonstrate that HT-Taqman PCR is a powerful tool that can be used for measuring low concentrations of mRNA, and is highly accurate, reproducible, and amenable to high throughput analysis. Results suggest that HT-TaqMan is a reliable method for the quantification of low-expression genes and a powerful tool with HT capability for target identification/validation, structure-activity relationship (SAR) study, compound selection for efficacy studies, and biomarker identification in drug discovery and development.

Drug Design↗
PubMed2003

Activity-dependent neuroprotective protein: a novel gene essential for brain formation.

We have recently cloned the novel homeobox-containing activity-dependent neuroprotective protein (ADNP). In the current study, mouse ADNP was shown to be expressed at the time of neural tube closure, detected at E7.5 and increased on E9.5. Expression was augmented in the brain (E12.5), sustained throughout embryogenesis and regulated by VIP. To assess the function of ADNP, knockout mice were established. Detailed analysis revealed cranial neural tube closure failure and death on E8.5-9.0 of the ADNP-knockout embryos. The expression of Oct4, a gene associated with germ-line maintenance was markedly augmented in the knockout embryos. In contrast, the expression of Pax6, a gene crucial for cerebral cortex formation, was abolished in the brain primordial tissue of the knockout embryos. Thus, Pax6 and Oct4 constitute a part of the mechanism of action of ADNP on brain formation, inhibiting germ-line division while activating morphogenesis. In conclusion, ADNP is identified here as a new key gene essential for organogenesis in the developing embryo and may be implicated as a clinical target associated with proper neurodevelopment.

Animals↗
PubMed2003

Differential effects of ethanol antagonism and neuroprotection in peptide fragment NAPVSIPQ prevention of ethanol-induced developmental toxicity.

NAPVSIPQ (NAP), an active fragment of the glial-derived activity-dependent neuroprotective protein, is protective at femtomolar concentrations against a wide array of neural insults and prevents ethanol-induced fetal wastage and growth retardation in mice. NAP also antagonizes ethanol inhibition of L1-mediated cell adhesion (ethanol antagonism). We performed an Ala scanning substitution of NAP to determine the role of ethanol antagonism and neuroprotection in NAP prevention of ethanol embryotoxicity. The Ser-Ile-Pro region of NAP was crucial for both ethanol antagonism and protection of cortical neurons from tetrodotoxin toxicity (neuroprotection). Ala replacement of either Ser-5 or Pro-7 (P7A-NAP) abolished NAP neuroprotection but minimally changed the efficacy of NAP ethanol antagonism. In contrast, Ala replacement of Ile-6 (I6A-NAP) caused a decrease in potency (>2 logarithmic orders) with only a small reduction (<10%) in the efficacy of NAP neuroprotection but markedly reduced the efficacy (50%) and the potency (5 logarithmic orders) of NAP ethanol antagonism. Ethanol significantly reduced the number of paired somites in mouse whole-embryo culture; this effect was prevented significantly by 100 pM NAP or by 100 pM P7A-NAP, but not by 100 pM I6A-NAP. The structure-activity relation for NAP prevention of ethanol embryotoxicity was similar to that for NAP ethanol antagonism and different from that for NAP neuroprotection. These findings support the hypothesis that NAP antagonism of ethanol inhibition of L1 adhesion plays a central role in NAP prevention of ethanol embryotoxicity and highlight the potential importance of ethanol effects on L1 in the pathophysiology of fetal alcohol syndrome.

Abnormalities, Drug-Induced↗
PubMed2003

The neuroprotective peptide NAP inhibits the aggregation of the beta-amyloid peptide.

Alzheimer's disease (AD) is characterized by brain plaques containing the beta-amyloid peptide (Abeta). One approach for treating AD is by blocking Abeta aggregation. Activity-dependent neuroprotective protein contains a peptide, NAP that protects neurons in culture against Abeta toxicity. Here, NAP was shown to inhibit Abeta aggregation using: (1) fluorimetry; (2) electron microscopy; (3) high-throughput screening of Abeta deposition onto a synthetic template (synthaloid); and (4) Congo Red staining of neurons. Further assays showed biotin-NAP binding to Abeta. These results suggest that part of the neuroprotective mechanism exerted by NAP is through modulation of toxic protein folding in the extracellular milieu.

Alzheimer Disease↗
PubMed2003

Vasoactive intestinal peptide in the brain of a mouse model for Down syndrome.

The most common genetic cause of mental retardation is Down syndrome, trisomy of chromosome 21, which is accompanied by small stature, developmental delays, and mental retardation. In the Ts65Dn segmental trisomy mouse model of Down syndrome, the section of mouse chromosome 16 most homologous to human chromosome 21 is trisomic. This model exhibits aspects of Down syndrome including growth restriction, delay in achieving developmental milestones, and cognitive dysfunction. Recent data link vasoactive intestinal peptide malfunction with developmental delays and cognitive deficits. Blockage of vasoactive intestinal peptide during rodent development results in growth and developmental delays, neuronal dystrophy, and, in adults, cognitive dysfunction. Also, vasoactive intestinal peptide is elevated in the blood of newborn children with autism and Down syndrome. In the current experiments, vasoactive intestinal peptide binding sites were significantly increased in several brain areas of the segmental trisomy mouse, including the olfactory bulb, hippocampus, cortex, caudate/putamen, and cerebellum, compared with wild-type littermates. In situ hybridization for VIP mRNA revealed significantly more dense vasoactive intestinal peptide mRNA in the hippocampus, cortex, raphe nuclei, and vestibular nuclei in the segmental trisomy mouse compared with wild-type littermates. In the segmental trisomy mouse cortex and hippocampus, over three times as many vasoactive intestinal peptide-immunopositive cells were visible than in wild-type mouse cortex. These abnormalities in vasoactive intestinal peptide parameters in the segmental trisomy model of Down syndrome suggest that vasoactive intestinal peptide may have a role in the neuropathology of Down-like cognitive dysfunction.

Animals↗
PubMed2003

Complex array of cytokines released by vasoactive intestinal peptide.

A complex mixture of five cytokines has been shown to be released by vasoactive intestinal peptide (VIP). Cytokines were measured in paired samples of culture medium and astroglial cytosol by capillary electrophoresis. This is the first description of VIP-mediated release for TNF-alpha, IL-3, G-CSF and M-CSF from astrocyte cultures. Kinetic studies after VIP treatment demonstrated a gradual but incomplete depletion of cytosolic cytokine levels, with differences observed among the cytokines. Significant increases in release were apparent within 15-30 min for all cytokines. As the recognized VIP receptors (VPAC1 and VPAC2) are linked to adenylate cyclase and also interact with pituitary adenylate cyclase activating polypeptide-38 (PACAP-38), both this homologous peptide and 8-bromo cAMP were investigated and compared to VIP-mediated release. Treatment with 1 mM 8-bromo cAMP produced cytokine release similar in amount to 0.1 nM PACAP-38, but significantly less (<50%) in comparison to 0.1 nM VIP. PACAP-38 and VIP exhibited similar EC(50)'s for the release of G-CSF and TNF-alpha; however, the maximal release was 4-6 times greater for VIP than for PACAP-38. This similarity in potency suggested a VPAC-like receptor; however, the greater efficacy for VIP in comparison to PACAP-38, combined with a lack of cAMP production at subnanomolar concentrations of VIP, suggested a mechanism not currently associated with VPAC receptors. For M-CSF, IL-3 and IL-6, the EC(50)'s of VIP were 3-30 times more potent than those of PACAP-38 in producing release. These studies suggested that multiple mechanisms mediate cytokine release in astrocytes: (1) a low efficacy release produced by PACAP-38 that is cAMP-mediated and (2) a high efficacy, VIP-preferring mechanism that was not linked to cAMP. In summary, subnanomolar concentrations of VIP released a complex array of cytokines from astrocytes that may contribute to the mitogenic and neurotrophic properties of this neuropeptide in the central nervous system.

Adenylyl Cyclases↗
PubMed2003

The role of activity-dependent neuroprotective protein in a mouse model of fetal alcohol syndrome.

OBJECTIVE: Fetal alcohol syndrome (FAS) is the most common nongenetic cause of mental retardation. Peptides NAPVSIPQ (NAP) and SALLRSIPA (SAL), related to activity-dependent neuroprotective protein (ADNP), prevent alcohol-induced damage in a mouse model of FAS. Our objective was to characterize ADNP in this model to relate this protein to the mechanisms of damage and peptide neuroprotection. STUDY DESIGN: Timed, pregnant C57Bl6/J mice were treated on day 8. Groups were control, alcohol, peptide pretreatment, or peptide alone. Embryo and decidua were harvested at 6 and 24 hours and 10 days. To evaluate ADNP expression, real-time polymerase chain reaction was performed with results presented as the ratio of ADNP-to-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) concentration. Analysis of variance was performed for overall comparisons with P<.05 considered significant. RESULTS: At 6 hours, there was no difference in ADNP between alcohol-exposed embryos compared with control embryos. At 24 hours, there was an increase in ADNP in alcohol-exposed embryos compared with controls (P<.001); these findings persisted at 10 days (P<.001). In the decidua at 6 hours, there was no difference between alcohol and control. At 24 hours, there was greater ADNP in alcohol-exposed decidua compared with controls (P<.001), which did not persist at 10 days (P=.97). Peptide pretreatment did not prevent the alcohol-induced increase in ADNP in embryo or decidua. CONCLUSION: Alcohol increased embryonic and decidual ADNP expression at 24 hours and it persisted in the embryo for 10 days. Because ADNP is a known neuroprotectant, these findings suggest that it may be released as a protective mechanism in FAS. Changes in the embryo were persistent suggesting that the embryo is more vulnerable to alcohol-induced damage than the mother.

Animals↗
PubMed2003

Differential expression of c-fos in a mouse model of fetal alcohol syndrome.

OBJECTIVE: Fetal alcohol syndrome (FAS) results in stillbirth, fetal growth restriction, and mental retardation with injury attributed to oxidative stress. Our objective was to identify signal transduction pathways expressed in a model of FAS and to quantify expression of c-fos, a gene in the stress signal pathway. STUDY DESIGN: Timed, pregnant C57Bl6/J mice were injected on E8 with saline solution or alcohol. RNA was extracted from decidua and embryo 6 and 24 hours later. Microarray analysis was used to screen gene pathways. Differential gene expression was confirmed using real-time polymerase chain reaction with results presented as the ratio of c-fos concentration to that of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). RESULTS: Differential gene expression between alcohol and control was noted for stress signal pathway genes including c-fos. Real-time polymerase chain reaction demonstrated that c-fos messenger RNA expression was greater in the alcohol than control decidua at 6 hours after injection (P<.01). This effect persisted at 24 hours (P<.01). There was no difference in c-fos expression in embryos whose mothers received alcohol versus control after 6 hours (P=.12) or 24 hours (P=.89). CONCLUSION: Alcohol administration during pregnancy results in differential gene expression in the stress signal pathway, particularly in c-fos. C-fos expression in the decidua increases from 6 to 24 hours after alcohol injection, but does not change in the embryo, which may contribute to alcohol-induced damage in FAS.

Animals↗
PubMed2003

Antagonism of VIP-stimulated cyclic AMP formation in chick brain.

Of eight peptides tested (0.01-5 microM), only two, that is, pituitary adenylate cyclase-activating polypeptide (PACAP27) and chicken vasoactive intestinal peptide (cVIP), potently stimulated cyclic AMP (cAMP) production in cerebral cortical slices of the chick. Mammalian VIP (mVIP) showed some activity only at the highest dose tested, whereas truncated forms of PACAP or VIP, that is, PACAP6-27, cVIP6-28, and mVIP6-28, or hybrid compounds, that is, neurotensin6-11-cVIP7-28 (NT-cVIP) and neurotensin6-11-mVIP7-28 (NT-mVIP), were inactive. Thirty-minute preincubation of chick cortical slices with 5 microM PACAP6-27, NT-cVIP, or NT-mVIP competitively antagonized the cAMP effects of cVIP (0.03-1 microM), with the truncated form of PACAP being the best antagonist. Preincubation of slices with 5 microM mVIP6-28 also produced a significant inhibition of the cVIP (0.1-1 microM)-induced increase in cAMP production; however its action was independent of the concentration of cVIP. In contrast to mVIP6-28, cVIP6-28 showed no antagonistic activity against the full-length peptide. In parallel experiments, 30-min pretreatment of cortical slices with 5 microM PACAP6-27 significantly antagonized the PACAP38-evoked increase in cAMP formation, whereas mVIP6-28 or the NT-mVIP hybrid was ineffective. It has been concluded that in the chick brain, PACAP and cVIP stimulate cAMP biosynthesis via PAC1 and VPAC-type receptors, respectively, and PACAP6-27 seems to be the most potent, yet PACAP/VIP receptor-nonselective antagonist. Unlike truncated PACAP, the NT-VIP hybrid peptides tested may represent VPACtype receptor-selective blocking activity.

Animals↗
PubMed2003

From vasoactive intestinal peptide (VIP) through activity-dependent neuroprotective protein (ADNP) to NAP: a view of neuroprotection and cell division.

Accelerated neuronal death brings about cognitive as well as motor and other dysfunctions. A major neuropeptide, vasoactive intestinal peptide (VIP), has been shown to be neuroprotective. However, VIP-based drug design is hampered by the instability of the peptide and its limited bioavailability. Two independent approaches were thus taken to exploit VIP as a lead drug candidate: (1) Potent neuroprotective lipophilic analogs of VIP were synthesized, e.g. [stearyl-norleucine-17] VIP (SNV); and (2) potent neuroprotective peptide derivatives were identified that mimic the activity of VIP-responsive neuroprotective glial proteins. VIP provides neuronal defense by inducing the synthesis and secretion of neuroprotective proteins from astrocytes; activity-dependent neuroprotective protein (ADNP) was discovered as such glial cell mediator of VIP- and SNV-induced neuroprotection. In subsequent studies, an eight-amino-acid peptide, NAP, was identified as the smallest active element of ADNP exhibiting potent neuroprotective activities. This paper summarizes the biological effects of SNV and NAP and further reports advances in NAP studies toward clinical development. An original finding described here shows that NAP, while protecting neurons, demonstrated no apparent effect on cell division in a multiplicity of cell lines, strengthening the notion that NAP is a specific neuroprotective drug candidate.

Animals↗
PubMed2002

The increased proliferation of cultured neuroblastoma cells treated with vasoactive intestinal peptide is enhanced by simultaneous inhibition of neutral endopeptidase.

Vasoactive intestinal peptide (VIP) stimulates the neuroblastoma cell line (NMB) to proliferate. Neuropeptide activity can be inhibited by neutral endopeptidases that function intracellularly and in the extracellular milieu. NMB cells express neutral endopeptidase (NEP) activity that can be specifically inhibited by phosphoramidon (PA). Our data now show that phosphoramidon treatment increases the efficacy of VIP-stimulated neuroblastoma proliferation. These results suggest that membrane endopeptidases modulate VIP-associated cell proliferation and enhancement of endopeptidase activity may serve as a target for cancer therapy.

Cell Division↗