Social defeat-induced Cingulate gyrus immediate-early gene expression and anxiolytic-like effect depend upon social rank.

Social hierarchy is considered to impart an adaptive advantage to the species by reducing long-term conflict between conspecifics. While social stratification is frequently established via stress-inducing stimuli, the subsequent integration of individuals into the hierarchy may attenuate anxiety. Presently, we hypothesized that repeated reinforcement of murine social hierarchy in the dominant-submissive relationship (DSR) food-competition test would engender divergent neuroplastic changes mediating both social and anxiety-like behavior among selectively-bred Dominant (Dom) and Submissive (Sub) mice. Two weeks of repeated respective social victory or defeat reduced serum corticosterone levels of both Dom and Sub mice, whereas socially-defeated Sub mice demonstrated markedly greater exploration of the open arms of the elevated plus maze (EPM). At the same time, social victory led to markedly greater expression of the immediate-early genes (IEGs) c-Jun and EGR-1 in the lateral septal nucleus (LSN) among Dom mice, in contrast with defeated Sub counterparts which demonstrated four-fold greater IEG expression in the cingulate gyrus (Cg). These findings point towards involvement of the Cg in the anxiety-like effect among Sub mice after repeated social defeat, and suggest stabilization of the social hierarchy to attenuate the stress-inducing nature of social interaction, particularly for subordinates. Further study of the potentially anxiolytic-like effects of Cg activity should shed light upon the functional significance of the Cg in social interaction, social hierarchical sorting and anxiety.

Endocannabinoid receptor deficiency affects maternal care and alters the dam's hippocampal oxytocin receptor and brain-derived neurotrophic factor expression.

Maternal care is the newborn's first experience of social interaction, and this influences infant survival, development and social competences throughout life. We recently found that postpartum blocking of the endocannabinoid receptor-1 (CB1R) altered maternal behaviour. In the present study, maternal care was assessed by the time taken to retrieve pups, pups' ultrasonic vocalisations (USVs) and pup body weight, comparing CB1R deleted (CB1R KO) versus wild-type (WT) mice. After culling on postpartum day 8, hippocampal expression of oxytocin receptor (OXTR), brain-derived neurotrophic factor (BDNF) and stress-mediating factors were evaluated in CB1R KO and WT dams. Comparisons were also performed with nulliparous (NP) CB1R KO and WT mice. Compared to WT, CB1R KO dams were slower to retrieve their pups. Although the body weight of the KO pups did not differ from the weight of WT pups, they emitted fewer USVs. This impairment of the dam-pup relationship correlated with a significant reduction of OXTR mRNA and protein levels among CB1R KO dams compared to WT dams. Furthermore, WT dams exhibited elevated OXTR mRNA expression, as well as increased levels of mineralocorticoid and glucocorticoid receptors, compared to WT NP mice. By contrast, CB1R KO dams showed no such elevation of OXTR expression, alongside lower BDNF and mineralocorticoid receptors, as well as elevated corticotrophin-releasing hormone mRNA levels, when compared to CB1R KO NP. Thus, it appears that the disruption of endocannabinoid signalling by CB1R deletion alters expression of the OXTR, apparently leading to deleterious effects upon maternal behaviour.

Different levels of gamma-synuclein mRNA in the cerebral cortex of dominant, neutral and submissive rats selected in the competition test.

Synucleins are small proteins regulating the filamentous network that in turn influences the release of dopamine and glutamate neurotransmitters involved in mood and motivation processes. We have studied the pattern of synuclein expression in animal models for mania and depression. Dominant behavior, as defined in a food competition test with dyads of rats, can serve as a model of mania and submissive behavior as a model of depression. The expression of alpha-, beta- and gamma-synuclein was analyzed in four regions of cortex from dominant, neutral and submissive rats using TaqMan reverse transcription-polymerase chain reaction technology. The expression levels of gamma-synuclein were elevated consistently in all regions of cerebral cortex of dominant rats (P <0.05; 23.5 +/- 1.1, normalized units) in contrast to the submissive rat group (10.3 +/- 1.2). Neutral rats had intermediate cerebral cortex levels of gamma-synuclein expression (15.7 +/- 1.4) that were significantly lower than that in dominant rats (P <0.05). No changes in alpha- or beta-synuclein expression were observed among the groups. These studies indicate that gamma-synuclein levels in the cerebral cortex were differentially associated with dominant and submissive behavior.

Common mutations in the familial Mediterranean fever gene associate with rapid progression to disability in non-Ashkenazi Jewish multiple sclerosis patients.

Ancient founder mutations in the Mediterranean fever gene, MEFV, are associated with familial Mediterranean fever, a recessive, episodic, inflammatory disease. Since these mutations are reported to express with above normal levels of acute phase reactants in healthy heterozygotes we postulated that the heterozygous phenotype could aggravate the clinical expression of ongoing autoimmune diseases. This study evaluated progression to disability in relapsing-remitting multiple sclerosis (RR-MS) patients of non-Ashkenazi and Ashkenazi origin carrying an MEFV mutation, particularly the detrimental M694V, using the expanded disability status scale (EDSS). In the non-Ashkenazi patients group (n=48), carriers (n=17) presented with a two-fold higher fraction which reached EDSS=3.0 and 6.0 compared to noncarriers (n=31) despite a comparable mean of MS duration. The median time to reach EDSS=3.0 was 2 years in the carriers vs 10 years in noncarriers (P=0.007); The median time to reach EDSS=6.0 was 6 years vs 23 years, respectively (P=0.003). M694V heterozygous patients reached both EDSS milestones earlier than other patients. Progression to disability was not enhanced in Ashkenazi RR-MS carriers (n=12, noncarriers n=59). In conclusion, non-Asheknazi MS patients carrying one mutated MEFV gene, particularly M694V, expressed rapid progression to disability. The expressed mutation may increase inflammatory damage inflicted by autoimmune responses.

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.

Activity-dependent neurotrophic factor: intranasal administration of femtomolar-acting peptides improve performance in a water maze.

Activity-dependent neurotrophic factor (ADNF) is a glia-derived protein that is neuroprotective at femtomolar concentrations. A nine-amino acid peptide derived from ADNF (Ser-Ala-Leu-Leu-Arg-Ser-Ile-Pro-Ala; ADNF-9) captured the activity of the parent protein and has been reported to protect cultured neurons from multiple neurotoxins. Antibodies recognizing ADNF-9 produced neuronal apoptosis, and identified an additional, structurally related, glia-derived peptide, Asn-Ala-Pro-Val-Ser-Ile-Pro-Gln (NAP). Previous comparative studies have characterized s.c.-injected NAP as most efficacious in protecting against developmental retardation and learning impairments in apolipoprotein E-deficient mice. This study was designed to assess 1) neuroprotection after intranasal administration of ADNF-9 and NAP to rats treated with the cholinotoxin ethylcholine aziridium; and 2) bioavailability and pharmacokinetics after intranasal administration. Results showed significant improvements in short-term spatial memory, as assessed in a water maze, after daily intranasal administration of 1 microg of peptide (ADNF-9 or NAP) per animal. However, a 5-day pretreatment with ADNF-9 did not improve performance measured after cessation of treatment. Compared with rats treated with ADNF-9, NAP-pretreated animals exhibited a significantly better performance. Furthermore, NAP (and not ADNF-9) protected against loss of choline acetyl transferase activity. Significant amounts of (3)H-labeled NAP reached the brain, remained intact 30 min after administration, and dissipated 60 min after administration. This study revealed efficacy for ADNF-related peptides in rodent models for neurodegeneration. The small size of the molecules, the low dosage required, the noninvasive administration route, and the demonstrated activity in a relevant paradigm suggest NAP as a lead compound for future drug design.

A novel VIP responsive gene. Activity dependent neuroprotective protein.

Activity dependent neuroprotective protein (ADNP, 828 amino acids, pI 5.99) is a glial-derived protein that contains a femtomolar active neuroprotective peptide, NAPVSIPQ (NAP). VIP induces a two- to threefold increase in ADNP mRNA in astrocytes, suggesting that ADNP is a VIP-responsive gene. ADNP is widely distributed in the mouse hippocampus, cerebellum, and cerebral cortex. VIP has been shown to possess neuroprotective activity that may be exerted through the activation of glial proteins. We suggest that ADNP may be part of the VIP protection pathway through the femtomolar-acting NAP and through putative interaction with other macromolecules.

A femtomolar-acting neuroprotective peptide induces increased levels of heat shock protein 60 in rat cortical neurons: a potential neuroprotective mechanism.

Activity-dependent neurotrophic factor (ADNF) was recently isolated from conditioned media of astrocytes stimulated with vasoactive intestinal peptide (VIP). ADNF provided neuroprotection at femtomolar concentration against a wide variety of toxic insults. A nine amino acid peptide (ADNF-9) captured with even greater potency the neuroprotective activity exhibited by the parent protein. Utilizing Northern and Western blot analyses, it was now shown that ADNF-9 increased the expression of heat shock protein 60 (hsp60) in rat cerebral cortical cultures. In contrast, treatment with the Alzheimer's toxin, the beta-amyloid peptide, reduced the amount of intracellular hsp60. Treatment with ADNF-9 prevented the reduction in hsp60 produced by the beta-amyloid peptide. The protection against the beta-amyloid peptide-associated cell death provided by ADNF-9 may be mediated in part by intracellular increases in hsp60.

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.

A novel signaling molecule for neuropeptide action: activity-dependent neuroprotective protein.

The complete coding sequence of a novel protein (828 amino acids, pI 5.99), a potential new mediator of vasoactive intestinal peptide (VIP) activity was recently revealed. The expression of this molecule, activity-dependent neuroprotective protein (ADNP), was augmented in the presence of VIP, in cerebral cortical astrocytes. The mRNA transcripts encoding ADNP were enriched in the mouse hippocampus and cerebellum. The protein deduced sequence contained the following: (1) a unique peptide, NAPVSIPQ, sharing structural and immunological homologies with the previously reported, activity-dependent neurotrophic factor (ADNF) and exhibiting neuroprotection in vitro and in vivo; (2) a glutaredoxin active site; and (3) a classical zinc binding domain. Comparative studies suggested that the peptide, NAPVSIPQ (NAP), was more efficacious than peptides derived from ADNF. ADNP, a potential mediator of VIP-associated neuronal survival, and the new peptide, a potential lead compound for drug design, are discussed below.