Hepatocellular carcinoma chemoprevention by targeting the angiotensin-converting enzyme and EGFR transactivation

Hepatocellular carcinoma (HCC) is a leading cause of death among cirrhotic patients, for which chemopreventive strategies are lacking. Recently, we developed a simple human cell-based system modeling a clinical prognostic liver signature (PLS) predicting liver disease progression and HCC risk. In a previous study, we applied our cell-based system for drug discovery and identified captopril, an approved angiotensin converting enzyme (ACE) inhibitor, as a candidate compound for HCC chemoprevention. Here, we explored ACE as a therapeutic target for HCC chemoprevention. Captopril reduced liver fibrosis and effectively prevented liver disease progression toward HCC development in a diethylnitrosamine (DEN) rat cirrhosis model and a diet-based rat model for nonalcoholic steatohepatitis–induced (NASH-induced) hepatocarcinogenesis. RNA-Seq analysis of cirrhotic rat liver tissues uncovered that captopril suppressed the expression of pathways mediating fibrogenesis, inflammation, and carcinogenesis, including epidermal growth factor receptor (EGFR) signaling. Mechanistic data in liver disease models uncovered a cross-activation of the EGFR pathway by angiotensin. Corroborating the clinical translatability of the approach, captopril significantly reversed the HCC high-risk status of the PLS in liver tissues of patients with advanced fibrosis. Captopril effectively prevents fibrotic liver disease progression toward HCC development in preclinical models and is a generic and safe candidate drug for HCC chemoprevention.

Disease modifying treatment trials in Parkinson's disease: how to balance expectations and interests of patients, physicians and industry partners?

Background

The advent of therapeutic strategies designed to modify the disease course in Parkinson’s disease has raised great expectations in the currently conducted clinical trials. However, we see ethical challenges in the cooperation of industry and clinical partners, specifically evident in the way recruitment is performed.

We here discuss the different positions and challenges of all involved to set the stage for a study and recruitment culture taking into account the expectations of all: (i) patients and their caregivers, ready to take the considerable burden of clinical trials in hope for the development of disease-modifying treatments; (ii) physicians and study nurses, obligated to the patients’ well-being and benefit who accompany and supervise patients closely as basis for the performance of elaborate clinical trials (iii) industrial partners, investing years of efforts and finances to develop new treatments.

Conclusions

We conclude that the current competitive race for enrollment in clinical studies in PD is challenging the primary goal to ensure patients’ benefit and formulate requests to the industrial partners to encounter these concerns.

How to evaluate effects of occupational therapy - lessons learned from an exploratory randomized controlled trial

BACKGROUND

Although occupational therapy (OT) is frequently prescribed in clinical practice, there is still insufficient evidence regarding its efficacy to improve Parkinson's Disease (PD)-related activity limitations.

OBJECTIVES

To evaluate the efficacy of OT and the validity of different outcome-parameters to reflect efficacy, including gold-standard clinical rating scales and quantitative motor assessments.

METHODS

40 patients were included in an exploratory, randomized-controlled, single-blinded trial, receiving either (I) ten weeks of OT, with a main focus on motor aspects of activity limitations and a ten-week follow-up assessment or (II) no intervention. Inclusion criteria were diagnosis of PD and Hoehn & Yahr stage 2-3. Patients with major depression, other neurological or orthopedic diseases or OT beforehand were excluded from the study. To monitor treatment effects the MDS-UPDRS part II and III were used for patient- and clinician-based assessment. Objective Pegboard as well as Q-Motor "tremormotography" and "digitomotography" were applied.

RESULTS

The interventional group reported a subjective amelioration of activity limitations, with a significant improvement of MDS-UPDRS part II at the end of the study (p = 0.030). However, clinician's rating and quantitative motor assessment failed to detect a significant improvement of motor impairment and fine motor control.

CONCLUSIONS

This study goes in line with previous trials, showing an individual improvement of activity limitations from the patients' point of view. The discrepancy between self-perception, focusing on activity limitation, and clinician-based rating, focusing on motor impairment, challenges the current gold standard assessments as valid outcome parameters for occupational therapy trials aiming for an individualized improvement of disease burden.

GBA-associated parkinsonism and dementia: beyond α-synucleinopathies?

BACKGROUND AND PURPOSE

To date the role of GBA mutations beyond α-synucleinopathies in the parkinsonism-dementia spectrum is still unclear. The aim of the study was to screen for GBA mutations in progressive supranuclear palsy (PSP), corticobasal syndrome (CBS), primary progressive aphasia (PPA) and the behavioural variant of frontotemporal dementia (bvFTD).

METHODS

In all, 303 patients with a clinical diagnosis of PSP (n = 157), CBS (n = 39), PPA (n = 35) and bvFTD (n = 72) and 587 neurologically healthy controls were screened for the most common GBA mutations.

RESULTS

GBA mutations were detected in one healthy control and four patients with a clinical diagnosis of PSP (n = 1), probable CBS (n = 2) and PPA (n = 1, with concomitant C9orf72 expansion). Overall the prevalence of GBA mutations was low in non-α-synucleinopathies but significantly higher in the CBS subgroup compared to controls.

CONCLUSION

Although numbers are small, our findings indicate that the clinical phenotype of GBA-associated neurodegenerative disease is more heterogeneous than previously assumed, including phenotypes not usually associated with underlying α-synucleinopathies. This may be of relevance, once causal therapeutic strategies for GBA-associated neurodegenerative disease are developed.

Pharmacological profile of the alpha4beta2 nicotinic acetylcholine receptor partial agonist varenicline, an effective smoking cessation aid

The preclinical pharmacology of the alpha4beta2 nicotinic acetylcholine receptor (nAChR) partial agonist varenicline, a novel smoking cessation agent is described. Varenicline binds with subnanomolar affinity only to alpha4beta2 nAChRs and in vitro functional patch clamp studies in HEK cells expressing nAChRs show that varenicline is a partial agonist with 45% of nicotine's maximal efficacy at alpha4beta2 nAChRs. In neurochemical models varenicline has significantly lower (40-60%) efficacy than nicotine in stimulating [(3)H]-dopamine release from rat brain slices in vitro and in increasing dopamine release from rat nucleus accumbens in vivo, while it is more potent than nicotine. In addition, when combined with nicotine, varenicline effectively attenuates the nicotine-induced dopamine release to the level of the effect of varenicline alone, consistent with partial agonism. Finally, varenicline reduces nicotine self-administration in rats and supports lower self-administration break points than nicotine. These data suggest that varenicline can reproduce to some extent the subjective effects of smoking by partially activating alpha4beta2 nAChRs, while preventing full activation of these receptors by nicotine. Based on these findings, varenicline was advanced into clinical development and recently shown to be an effective and safe aid for smoking cessation treatment.

Inducible, brain region-specific expression of a dominant negative mutant of c-Jun in transgenic mice decreases sensitivity to cocaine

Administration of cocaine induces the Fos family of transcription factors in the striatum, including the nucleus accumbens (NAc), a brain region important for the rewarding effects of addictive drugs. Several Fos proteins are induced acutely by cocaine, with stable isoforms of DeltaFosB predominating after chronic drug administration. However, it has been difficult to study the functional consequences of these Fos responses in vivo. Fos proteins heterodimerize with members of the Jun family to form active AP-1 transcription factor complexes. In the present study, we took advantage of this property and generated transgenic mice, using the tetracycline gene regulation system, that support the inducible, brain region-specific expression of a dominant negative mutant form of c-Jun (Deltac-Jun), which can antagonize the actions of Fos proteins. Expression of Deltac-Jun in the striatum and certain other brain regions of adult mice decreases their development of cocaine-induced conditioned place preference, suggesting reduced sensitivity to the rewarding effects of cocaine. In contrast, Deltac-Jun expression had no effect on cocaine-induced locomotor activity or sensitization. However, expression of Deltac-Jun in adult mice blocked the ability of chronic cocaine administration to induce three known targets for AP-1 in the NAc: the AMPA glutamate receptor subunit GluR2, the cyclin-dependent protein kinase Cdk5, and the transcription factor nuclear factor-kappaB (NFkappaB), without affecting several other proteins examined for comparison. Taken together, these results provide further support for an important role of AP-1-mediated transcription in some of the behavioral and molecular mechanisms underlying cocaine addiction.

Induction of nuclear factor-kappaB in nucleus accumbens by chronic cocaine administration

DeltaFosB is a Fos family transcription factor that is induced by chronic exposure to cocaine and other drugs of abuse in the nucleus accumbens and related striatal regions, brain regions that are important for the behavioral effects of these drugs. To better understand the mechanisms by which DeltaFosB contributes to the effects of chronic drug treatment, we used DNA microarray analysis to identify genes that are regulated in the nucleus accumbens upon DeltaFosB expression in inducible bitransgenic mice. One of the most highly regulated genes was that encoding a subunit of another transcription factor, nuclear factor-kappaB (NF-kappaB). Subsequent experiments confirmed the induction of NF-kappaB in the nucleus accumbens of mice overexpressing DeltaFosB as well as in wild-type mice treated chronically, but not acutely, with cocaine. These results establish NF-kappaB as a putative target for DeltaFosB and implicate NF-kappaB signaling pathways in the long-term adaptations of nucleus accumbens neurons to cocaine.

Human immunodeficiency virus type 1 Nef functions at the level of virus entry by enhancing cytoplasmic delivery of virions

The Nef protein of the type 1 human immunodeficiency virus (HIV-1) plays a key although poorly understood role in accelerating the progression of clinical disease in vivo. Nef exerts several biological effects in vitro, including enhancement of virion infectivity, downregulation of CD4 and major histocompatibility complex class I receptor expression, and modulation of various intracellular signaling pathways. The positive effect of Nef on virion infectivity requires its expression in the producer cell, although its effect is manifested in the subsequent target cell of infection. Prior studies suggest that Nef does not alter viral entry into target cells; nevertheless, it enhances proviral DNA synthesis, arguing for an action of Nef at the level of viral uncoating or reverse transcription. However, these early studies discounting an effect of Nef on virion entry may be confounded by the recent finding that HIV enters cells by both fusion and endocytosis. Using epifluorescence microscopy to monitor green fluorescent protein-Vpr-labeled HIV virion entry into HeLa cells, we find that endocytosis forms a very active pathway for virus uptake. Virions entering via the endocytic pathway do not support productive infection of the host cell, presumably reflecting their inability to escape from the endosomes. Conversely, our studies now demonstrate that HIV Nef significantly enhances CD4- and chemokine receptor-dependent entry of HIV virions into the cytoplasmic compartment of target cells. Mutations in Nef either impairing its ability to downregulate CD4 or disrupting its polyproline helix compromise virion entry into the cytoplasm. We conclude that Nef acts at least in part as a regulator of cytosolic viral entry and that this action contributes to its positive effects on viral infectivity.

[Clinical assessment of schizophrenic syndromes (CASS): rationale, construction, reliability and sensitivity evaluation, and an attempt at normalization of the new diagnostic tool]

The CASS (Clinical Assessment of Schizophrenic Syndromes) is a new multi-purpose and multi-level clinical diagnostic instrument consisting of a diagnostic questionnaire (CASS-D) allowing for analysis of a diagnosis of schizophrenia according to DSM-IV and ICD-10 criteria, as well as of three rating scales designed for description and intensity evaluation of schizophrenic syndromes on the global (CASS-G), dimensional (CASS-P, a profile of 13 basic dimensions) or symptomatological (CASS-S, a set of 31 symptoms) level.

AIM

The paper presents a rationale and construction principles of the tool followed by a study of its reliability and sensitivity as well as by preliminary attempt to normalize its results.

SUBJECTS

Twelve trained diagnosticians assessed twice (at the start and end of their hospitalization) 194 inpatients admitted consecutively, within approximately 6 months, to the Department.

METHOD

Results of the CASS were compared with results of the SANS/SAPS, BPRS, and PANSS assessments playing the role of standard, reference instruments.

FINDINGS

High agreement coefficients (kappa) were calculated between a diagnosis of schizophrenia based on unoperationalized (clinical) criteria and operationalized diagnoses based on the CASS diagnostic questionnaire including ICD-10 and DSM-IV diagnostic criteria and algorithms. In the case of both complex (many-item) CASS scales (CASS-P, CASS-S) high reliability measures (internal consistency according to Cronbach's alpha) were found. Characteristics of frequency, intensity and dynamics of the CASS individual symptoms, dimensions and of syndrome as a whole were consistent with expectations based on clinical experience. Direct indices of clinical improvement calculated from CASS-G, CASS-P or CASS-S scores obtained at two time-points (admission, discharge) correlated fairly highly with more direct measures based on diagnosticians' clinical global impressions made when summing the results of treatment at discharge from the hospital. This finding suggests that CASS scores may sensitively register changes in patients' mental state during hospital stay and treatment. On the base of empirical distributions of CASS scales, a normalization (sten-scales) was proposed which may be useful for comparison of results obtained in differing groups of patients. Analysis of percentile and sten distributions of the CASS-P and CASS-S pointed out that patients with a diagnosis of schizophrenia had higher mean scores than patients with other diagnoses. This observation as well as above mentioned reasonableness (consistency with clinical experience) of a picture and dynamics of schizophrenic syndromes revealed in CASS assessments may be treated as preliminary assumptions of its content validity.

CONCLUSIONS

Results of the study suggest that CASS has satisfactory measures of reliability and sensitiveness. They allow for a preliminary normalization of its scales and prompt to study its validity.

[Clinical assessment of schizophrenic syndrome (CASS): validity evaluation of the new diagnostic tool]

AIM

The aim of the study was an evaluation of validity measures of the CASS (Clinical Assessment of Schizophrenic Syndromes)--a new multi-purpose and multi-level clinical diagnostic instrument consisting of a diagnostic questionnaire (CASS-D) allowing to analyze a diagnosis of schizophrenia according to DSM-IV and ICD-10 criteria as well as of three rating scales designed for description and intensity evaluation of schizophrenic syndromes on the global (CASS-G), dimensional (CASS-P, a profile of 13 basic dimensions) or symptomatological (CASS-S, a set of 31 symptoms) level.

SUBJECTS

194 inpatients consecutively admitted to the Department within approximately 6 months were assessed twice (at the start and end of their hospitalization) by 12 trained diagnosticians.

METHOD

Several measures of validity were analyzed. Results obtained by means of CASS were compared with results of the SANS/SAPS, BPRS, and PANSS as reference rating scales (diagnostic validity). Characteristics of frequency, intensity, dynamics and specificity of scale items were used to analyze content validity. Factorial structure of CASS scales was applied as a measure of construct validity.

FINDINGS

Diagnostic validity of the new instrument seems to be confirmed by its very high correlation coefficients with rating scales recognized as international standards: BPRS, PANSS, and SANS/SAPS. Reasonable characteristics of frequency, intensity, dynamics and specificity of individual items (dimensions, symptoms) and sum scores of CASS scales and relationships between their values strongly suggest their content validity. Both sum (CASS-P, CASS-S) and global (CASS-G) scores of scales under study revealed some specificity--they had significantly higher values in patients with schizophrenia than in patients with other diagnoses. It allows to distinguish in a schizophrenic syndrome described by CASS components which are specific and not specific for this disorder. The latter have been left also in the final version for their practical and clinical importance. Construct validity of the CASS was studied separately for different scales (CASS-P, CASS-S) and different groups (all or only schizophrenic patients) by means of several factor analyses, and performed along identical statistical procedure (principal component method of extraction with criterion eigenvalue > 1, followed by Equamax rotation). Resulting solutions could be interpreted reasonably and consistently with contemporary attempts to find adequate factorial models of intrinsic structure of schizophrenic syndrome. Thus they support confidence for constructive aspect of the CASS validity.

CONCLUSIONS

Ultimately, results obtained in the study suggest that the CASS may be considered as an instrument with some promising indices of diagnostic, content and construct validity, which may be potentially useful for clinical and research purposes.

The nuclear receptor chicken ovalbumin upstream promoter transcription factor interacts with HIV-1 Tat and stimulates viral replication in human microglial cells

Human immunodeficiency virus type 1 (HIV-1) infects the central nervous system and plays a direct role in the pathogenesis of AIDS dementia. However, the molecular mechanisms underlying HIV-1 expression in the central nervous system are poorly understood. We have recently reported that the nuclear receptor chicken ovalbumin upstream promoter transcription factor (COUP-TF), an orphan member of the nuclear receptor superfamily, is an activator of HIV-1 gene transcription. Here, our results show that COUP-TF stimulates HIV-1 transcription in primary cultured human microglial cells, the primary target for HIV-1 infection in brain. Run-on assays indicated that COUP-TF acts on the initiation step of transcription. Results from reverse transcription-polymerase chain reaction and immunocytochemistry analysis further revealed the importance of this factor by demonstrating that overexpression of COUP-TF leads to initiation of viral replication in primary HIV-infected human microglia. In addition, COUP-TF is able to physically interact and cooperate with the viral transactivator Tat. The combination of COUP-TF and Tat leads to NF-kappaB- and Sp1-independent enhanced transcriptional stimulation. In vitro binding studies showed that COUP-TF interacts with Tat through amino acids within the N-terminal DNA-binding domain of COUP-TF. Amino acids 48-72 in the basic and C-terminal regions of Tat are required for the binding of Tat to COUP-TF. These results suggest that COUP-TF is an essential transcription factor involved in HIV-1 expression in microglia and reveal a novel interplay of Tat and COUP-TF during regulation of viral expression.

Functional interactions between C/EBP, Sp1, and COUP-TF regulate human immunodeficiency virus type 1 gene transcription in human brain cells

Human immunodeficiency virus type 1 (HIV-1) infects the central nervous system (CNS) and plays a direct role in the pathogenesis of AIDS dementia. However, mechanisms underlying HIV-1 gene expression in the CNS are poorly understood. The importance of CCAAT/enhancer binding proteins (C/EBP) for HIV-1 expression in cells of the immune system has been recently reported. In this study, we have examined the role and the molecular mechanisms by which proteins of the C/EBP family regulate HIV-1 gene transcription in human brain cells. We found that NF-IL6 acts as a potent activator of the long terminal repeat (LTR)-driven transcription in microglial and oligodendroglioma cells. In contrast, C/EBPgamma inhibits NF-IL6-induced activation. Consistent with previous data, our transient expression results show cell-type-specific NF-IL6-mediated transactivation. In glial cells, full activation needs the presence of the C/EBP binding sites; however, NF-IL6 is still able to function via the minimal -40/+80 region. In microglial cells, C/EBP sites are not essential, since NF-IL6 acts through the -68/+80 LTR region, containing two binding sites for the transcription factor Sp1. Moreover, we show that functional interactions between NF-IL6 and Sp1 lead to synergistic transcriptional activation of the LTR in oligodendroglioma and to mutual repression in microglial cells. We further demonstrate that NF-IL6 physically interacts with the nuclear receptor chicken ovalbumin upstream promoter transcription factor (COUP-TF), via its DNA binding domain, in vitro and in cells, which results in mutual transcriptional repression. These findings reveal how the interplay of NF-IL6 and C/EBPgamma, together with Sp1 and COUP-TF, regulates HIV-1 gene transcription in brain cells.

Extended half-life and elevated steady-state level of a single-chain Fv intrabody are critical for specific intracellular retargeting of its antigen, caspase-7

8 h) and high steady-state levels of protein accumulation, while the H2 intrabodies had a half-life of 2 h and less protein at steady state. These results suggest that the choice of sFv as an intrabody depends critically on the intracellular sFv protein having an extended half-life and elevated steady-state level. Thus, extended half-life must be considered together with sFv antibody specificity and affinity when choosing an optimal sFv intrabody for functional studies of cellular proteins.

CREB and COUP-TF mediate transcriptional activation of the human immunodeficiency virus type 1 genome in Jurkat T cells in response to cyclic AMP and dopamine

Infection of lymphocytes by the human immunodeficiency virus type 1 (HIV-1) is associated with an increase in intracellular cAMP levels. Recent studies have shown that lymphocytes are able to synthesize and bind the dopamine, known to affect multiple cellular pathways, such as the cAMP pathway. Here we have investigated the molecular mechanisms by which cAMP and dopamine regulate HIV-1 gene transcription in Jurkat T cells. Transient expression experiments revealed that dopamine and forskolin lead to a synergistic stimulation of long terminal repeat (LTR)-driven transcription. This action is mediated through the cAMP response element binding (CREB) protein and chicken ovalbumin upstream promoter transcription factor (COUP-TF). CREB and COUP-TF act indirectly through the minimal -40/+80 and -68/+80 LTR region, respectively. We have previously demonstrated that COUP-TF stimulates HIV-1 transcription via the -68/+29 LTR region without direct DNA binding. Here, gel supershift experiments show that CREB does not directly bind to the -45/+85 proximal LTR sequences. Moreover, our data reveal novel functional interactions between COUP-TF and CREB, which lead to synergistic cAMP- and dopamine-induced transactivation of the HIV-1 LTR. These findings reveal that dopamine-induced signals and the cAMP pathway stimulate HIV-1 gene transcription in lymphocytes by converging to the minimal -68/+80 LTR region, through the transcription factors CREB and COUP-TF.

Dopamine stimulates expression of the human immunodeficiency virus type 1 via NF-kappaB in cells of the immune system

Recent studies have reported that lymphocytes produce, transport and bind dopamine present in plasma. However, the action of dopamine on HIV-1 gene expression in cells of the immune system has not yet been examined. Here, we have investigated the regulation of HIV-1 expression by dopamine in Jurkat T cells and in primary blood mononuclear cells (PBMC). HIV-1 replication was increased by dopamine, which correlated with the increased levels of HIV-1 transactivation. Our transient expression data revealed that dopamine stimulated transcription through the NF-kappaB element present in the long terminal repeat. The importance of NF-kappaB sites was confirmed by using vectors containing wild-type or mutant kappaB sites in a heterologous promoter. Consistent with the role of NF-kappaB in mediating dopamine responsiveness, the proteasome inhibitor MG132 abolished dopamine-induced transcriptional activation. We further explored the effect of dopamine in the presence of phorbol esters or tumor necrosis factor-alpha (TNF-alpha) known to activate NF-kappaB. The combination of dopamine and TNF-alpha led to a stimulation of HIV-1 transcription and replication. However, in contrast with TNF-alpha, dopamine treatment did not affect NF-kappaB DNA binding activity nor the concentrations of p50, p65 and IkappaB-alpha proteins, which suggests a distinct NF-kappaB activation mechanism. These results reveal a new link between the dopamine system, cytokine signaling pathway and regulation of gene expression via the involvement of NF-kappaB in T cells and PBMC.

[Psychopathological profile of acute schizophrenic syndromes diagnosed according to ICD-10 and DSM-IV criteria]

Diagnostic and symptomatological profiles of schizophrenic syndromes diagnosed according to ICD-10 and DSM-IV were compared. For this reason a group of patients fulfilling at least one of these sets of criteria was created and then diagnostic and symptomatological profile was compared between those who fulfilled the ICD-10 and those who fulfilled DSM-IV criteria. 105 inpatients hospitalized in acute phase of their first or one of consecutive episodes were included--102 of them had fulfilled ICD-10, and 90 DSM-IV criteria of schizophrenia. Diagnostic concordance between the two systems of criteria was high (83%). Differentiation of diagnostic profile (i.e. difference between frequency of fulfilling the specific requirements of ICD-10 or DSM-IV criteria) of the symptoms in these two groups was not significant, expert of 6-month criterion of duration of illness, which was significantly less frequently valid in ICD-10 syndromes group. A comparison of symptomatological profiles (i.e. frequency and intensity of symptoms) of schizophrenic syndromes diagnosed by ICD-10 or DSM-IV criteria and described by several rating scales (PANSS, SAPS/SANS, KOSS-S) did not show any significant differences. Results suggested that despite of different ways of defining the schizophrenic syndromes in both diagnostic systems, disorders manifested in the groups of patients created by means of them are very similar in psychopathological picture. This seems to be a significant change in comparison to more prominent differences contrasting the previous versions of the diagnostic systems (i.e. ICD-9 and DSM-III-R).

COUP-TF and Sp1 interact and cooperate in the transcriptional activation of the human immunodeficiency virus type 1 long terminal repeat in human microglial cells

We have recently reported that chicken ovalbumin upstream promoter transcription factor (COUP-TF) activates human immunodeficiency virus type 1 (HIV-1) gene transcription in glial and neuronal cells. Here, we have examined the role of COUP-TF in microglial cells, the major target cells for HIV-1 infection in brain. We show that COUP-TF activates gene expression from both the lymphotropic LAI and the macrophage-tropic JR-FL HIV-1 strains. Although COUP-TF binds to the -352/-320 nuclear receptor responsive element of the long terminal repeat, it functions as a transcriptional activator by acting on the -68/+29 minimal promoter. This region is a direct target of transcription factors Sp1 and Sp3. We report the discovery and features of a physical and functional interplay between COUP-TF and Sp1. Our cotransfection experiments provide evidence for a functional synergism between Sp1 and COUP-TF leading to enhanced transcriptional activity of the HIV-1 long terminal repeat through the Sp1 element. In contrast, Sp3 functions as a repressor of Sp1- or COUP-TF-induced activation. We further demonstrate that COUP-TF and Sp1 are capable of physically interacting, via the DNA-binding domain of COUP-TF, in vitro and in the cell. These findings reveal how the novel interplay of Sp1 and COUP-TF families of transcription factors regulate HIV-1 gene expression.

Functional deactivation of the major neuronal nicotinic receptor caused by nicotine and a protein kinase C-dependent mechanism

The effect of nicotine on the major human neuronal nicotinic receptor (alpha 4 beta 2 subtype) was studied in permanently transfected HEK 293 cells. Prolonged exposure to low concentrations of nicotine (1 microM) increased epibatidine binding but functionally deactivated the nicotinic receptor, abolishing Ca2+ influx in response to an acute nicotine challenge. Deactivation could also be caused by down-regulating protein kinase C (PKC) activity with 0.5 microM phorbol-12,13-dibutyrate or briefly incubating cells with the PKC inhibitor NPC-15437. Recovery from receptor deactivation caused by either nicotine treatment or PKC inhibition occurred slowly (4-6 hr). Reversal of nicotine-induced deactivation was accelerated by the addition of inhibitors of protein phosphatases 2A and 2B. These data suggest a hypothetical mechanism of nicotine-induced deactivation that involves dephosphorylation of nicotinic receptors at PKC phosphorylation sites.

Phosphorylation-dependent effects of synapsin IIa on actin polymerization and network formation

The synapsins are a family of synaptic vesicle phosphoproteins which play a key role in the regulation of neurotransmitter release and synapse formation. In the case of synapsin I, these biological properties have been attributed to its ability to interact with both synaptic vesicles and the actin-based cytoskeleton. Although synapsin II shares some of the biological properties of synapsin I, much less is known of its molecular properties. We have investigated the interactions of recombinant rat synapsin Ila with monomeric and filamentous actin and the sensitivity of those interactions to phosphorylation, and found that: i) dephosphorylated synapsin II stimulates actin polymerization by binding to actin monomers and forming actively elongating nuclei and by facilitating the spontaneous nucleation/elongation processes; ii) dephosphorylated synapsin II induces the formation of thick and ordered bundles of actin filaments with greater potency than synapsin I; iii) phosphorylation by protein kinase A markedly inhibits the ability of synapsin II to interact with both actin monomers and filaments. The results indicate that the interactions of synapsin II with actin are similar but not identical to those of synapsin I and suggest that synapsin II may play a major structural role in mature and developing nerve terminals, which is only partially overlapping with the role played by synapsin I.

Drugs acting upon the cyclic adenosine monophosphate/protein kinase A signalling pathway modulate memory consolidation when given late after training into rat hippocampus but not amygdala

Rats implanted bilaterally with cannulae in the CA1 region of the dorsal hippocampus or in the amygdala were trained in one-trial step-down inhibitory (passive) avoidance using a 0.4 mA footshock. At various times after training (0, 1.5, 3, 6 or 9 h for animals implanted in the hippocampus; 0 or 3 h for those implanted in the amygdala), they received infusions of 8-Br-cAMP (cyclic adenosine monophosphate) (1.25 micrograms/side), SKF38393 (7.5 micrograms/side), SCH23390 (0.5 microgram/side), norepinephrine ClH (0.3 microgram/side), timolol ClH (0.3 microgram/side), 8-HO-DPAT (2.5 micrograms/side), NAN-190 (2.5 micrograms/side), forskolin (0.5 microgram/side) or KT5720 (0.5 microgram/side). Rats were tested for retention 24 h after training. SKF38393 is an agonist and SCH23390 an antagonist at dopamine D1 receptors, timolol is a beta-adrenoceptor antagonist, 8-HO-DPAT is an agonist and NAN-190 an antagonist at 5HT1A receptors, forskolin enhances adenylyl cyclase, and KT5720 inhibits protein kinase A. When given into the hippocampus 0 h post-training, norepinephrine enhanced memory and KT5720 was amnestic. When given 1.5 h after training, all treatments were ineffective. When given 3 or 6 h post-training, 8-Br-cAMP, forskolin, SKF 38393, noradrenaline and NAN-190 caused memory facilitation, and KT5720, SCH23390, timolol and 8-HO-DPAT caused retrograde amnesia. At 9 h from training, all treatments were again ineffective. When given into the amygdala 0 or 3 h post-training all treatments were ineffective, except for noradrenaline at 0 h, which caused retrograde facilitation. The data agree with the suggestion that in the hippocampus, but not the amygdala, a cAMP/protein kinase A pathway is involved in memory consolidation at 3 and 6 h from training, and that this is regulated by D1, beta, and 5HT1A receptors. This correlates with a previous report of increased cAMP levels, protein kinase A activity and P-CREB levels at 3-6 h from training in rat hippocampus in this task. This may be taken to suggest that the hippocampus, but not the amygdala, is involved in the long-term storage of step-down inhibitory avoidance in the rat.

Agents that affect cAMP levels or protein kinase A activity modulate memory consolidation when injected into rat hippocampus but not amygdala

Male Wistar rats were trained in one-trial step-down inhibitory avoidance using a 0.4-mA footshock. At various times after training (0, 1.5, 3, 6 and 9 h for the animals implanted into the CA1 region of the hippocampus; 0 and 3 h for those implanted into the amygdala), these animals received microinfusions of SKF38393 (7.5 micrograms/side), SCH23390 (0.5 microgram/side), norepinephrine (0.3 microgram/side), timolol (0.3 microgram/side), 8-OH-DPAT (2.5 micrograms/side), NAN-190 (2.5 micrograms/side), forskolin (0.5 microgram/side), KT5720 (0.5 microgram/side) or 8-Br-cAMP (1.25 micrograms/side). Rats were tested for retention 24 h after training. When given into the hippocampus 0 h post-training, norepinephrine enhanced memory whereas KT5720 was amnestic. When given 1.5 h after training, all treatments were ineffective. When given 3 or 6 h post-training, 8-Br-cAMP, forskolin, SKF38393, norepinephrine and NAN-190 caused memory facilitation, while KT5720, SCH23390, timolol and 8-OH-DPAT caused retrograde amnesia. Again, at 9 h after training, all treatments were ineffective. When given into the amygdala, norepinephrine caused retrograde facilitation at 0 h after training. The other drugs infused into the amygdala did not cause any significant effect. These data suggest that in the hippocampus, but not in the amygdala, a cAMP/protein kinase A pathway is involved in memory consolidation at 3 and 6 h after training, which is regulated by D1, beta, and 5HT1A receptors. This correlates with data on increased post-training cAMP levels and a dual peak of protein kinase A activity and CREB-P levels (at 0 and 3-6 h) in rat hippocampus after training in this task. These results suggest that the hippocampus, but not the amygdala, is involved in long-term storage of step-down inhibitory avoidance in the rat.

[Assessment and self-assessment of patients' attitudes toward their psychotic disorders]

The aim of the study was the evaluation of concordance between rating and self-rating of attitudes toward psychotic disorders in one hundred patients (72 of them with diagnosis of schizophrenia). At discharge from the hospital patients were examined by two scales: Experience of Illness Scale (for rating) and My Experience of Illness Scale (for self-rating). Moderate concordance of results of rating and self-rating of the overall patients' attitude was noted. The higher concordance was found on dimension of evaluation of the illness experience, lower on dimension of reflectiveness to disease experience, and the lowest one on dimension of identification of the disease with self. Two different scales, simultaneously used, seem very beneficial because they reflected attitudes from two different perspectives, creating more complete a picture.

Sequential role of hippocampus and amygdala, entorhinal cortex and parietal cortex in formation and retrieval of memory for inhibitory avoidance in rats

The hippocampus and amygdala, the entorhinal cortex and the parietal cortex participate, in that sequence, both in the formation and in the expression of memory for a step-down inhibitory avoidance task in rats. Bilateral infusion of AP5 or muscimol caused retrograde amnesia when given 0 min after training into both hippocampus and amygdala, when given or 180 min after training into the entorhinal cortex, or when given 180 min after training into the parietal cortex. Therefore, memory formation requires the sequential and integrated activity of all these areas mediated by glutamate NMDA receptors in each case. Pre-test administration of CNQX 1 day after training into hippocampus and amygdala, 1 or 31 days after training in entorhinal cortex, or 1, 31 or 60 days after training in the parietal cortex temporarily blocked retention test performance. Therefore, 1 day after training, all these brain structures are necessary for retrieval; 1 month later, the hippocampus and amygdala are no longer necessary for retrieval but the entorhinal and parietal cortex still are; and 60 days after training only the parietal cortex is needed. In all cases the mechanisms of retrieval require intact glutamate AMPA receptors.

Characterization of nuclear proteins that bind to the regulatory TGATTGGC motif in the human immunodeficiency virus type 1 long terminal repeat

We have recently elucidated the nature and function of transcription factors present in Jurkat, glial and neuronal cells that interact with modulatory region B, the nuclear receptor responsive element, in the long terminal repeat of human immunodeficiency virus type 1 (HIV-1). Considering the key role that the combination of host cell proteins plays in HIV-1 gene transcription, it appears essential to characterize proteins interacting with the adjacent region A. In vitro experiments revealed that the 5'-TGATTGGC-3'motif of region A is the target for at least three distinct proteins, one belonging to the nuclear factor I family, while two others are related to the cAMP response element binding (CREB) protein family. One of these proteins, present in DNA-protein complex C2, is formed by distinct polypeptides of relative molecular mass 43 000 and 50 000. We have purified the 43 kDa protein, which is distinct from CREB-43, and have shown that renatured p43 is able to specifically interact with site A. Transient expression experiments with vectors containing wild-type or mutant motif A revealed that basal HIV-1 gene transcription in Jurkat cells is regulated by antagonistic effects of the site A binding proteins.

Involvement of the hippocampus, amygdala, entorhinal cortex and posterior parietal cortex in memory consolidation

A total of 182 young adult male Wistar rats were bilaterally implanted with cannulae into the CA1 region of the dorsal hippocampus and into the amygdaloid nucleus, the entorhinal cortex, and the posterior parietal cortex. After recovery, the animals were trained in a step-down inhibitory avoidance task. At various times after training (0, 30, 60 or 90 min) the animals received a 0.5-microliter microinfusion of vehicle (saline) or 0.5 microgram of muscimol dissolved in the vehicle. A retention test was carried out 24 h after training. Retention test performance was hindered by muscimol administered into both the hippocampus and amygdala at 0 but not at 30 min posttraining. The drug was amnestic when given into the entorhinal cortex 30, 60 or 90 min after training, or into the parietal cortex 60 or 90 min after training, but not before. These findings suggest a sequential entry in operation, during the posttraining period, of the hippocampus and amygdala, the entorhinal cortex, and the posterior parietal cortex in memory processing.

Chicken ovalbumin upstream promoter transcription factor, a transcriptional activator of HIV-1 gene expression in human brain cells

Viral infection of the central nervous system by the human immunodeficiency virus type 1 leads to a wide range of neuropathological disorders. However, the molecular mechanisms governing transcription of the human immunodeficiency virus type 1 genome in brain remain unclear. We have recently established that in brain cells, proteins belonging to the steroid/thyroid/retinoic acid receptor family bind to the -352 to -320 region of the long terminal repeat (LTR). Here, by supershift experiments, we have identified chicken ovalbumin upstream promoter transcription factor (COUP-TF), an orphan member of this nuclear receptor family, as one of the major proteins interacting with this LTR site. Cotransfection studies revealed that COUP-TF is able to dramatically activate LTR-directed gene transcription in human oligodendroglioma but not in astrocytoma cells. This activation occurs through two mechanisms, depending on the LTR sequence. Moreover, in neuronal cells COUP-TF and dopamine, a catecholamine neurotransmitter, enhance LTR-directed transcription by acting on the proximal LTR region. These results reveal the importance of COUP-TF and the dopamine signaling pathway as activators of human immunodeficiency virus type 1 gene expression in brain.

Regulation of human immunodeficiency virus type 1 gene transcription by nuclear receptors in human brain cells

Infection of cells of the central nervous system by the human immunodeficiency virus type-1 (HIV-1) leads to HIV-1-associated neuropathology. Recent studies have demonstrated the importance of long terminal repeat (LTR) binding sites in determining the pathogenicity of HIV. Here we have investigated the presence and the functional role of transcription factors that have the potential to interact, directly or indirectly, with the nuclear receptor-responsive element in the LTR of HIV-1, in different human cell lines of the brain. Cotransfection experiments showed that in oligodendroglioma TC-620 cells, the retinoic acid receptor and the retinoid X receptor activate LTR-driven transcription in the absence of ligand. Addition of all-trans- or 9-cis-retinoic acid reverses this effect. In contrast, in astrocytoma, neuronal, and microglial cells, no significant effect of the retinoid acid pathway was detected. This retinoid response is mediated by distinct molecular interactions in the lymphotropic LAI and the neurotropic JR-CSF HIV-1 strains. Moreover, retinoid receptors were found to antagonize the chicken ovalbumin upstream promoter transcription factor- as well as the c-JUN-mediated LTR transactivation. Our findings demonstrate the importance of the retinoic acid signaling pathway and of cross-coupling interactions in the repression of HIV-1 LTR gene expression.

Different brain areas are involved in memory expression at different times from training

Rats were trained in a step-down inhibitory avoidance task and tested for retention 1, 31, or 60 days later. Three to 7 days prior to testing, they were bilaterally implanted with cannulae in the CA1 region of the dorsal hippocampus and in the amygdaloid nucleus (H + A), in the entorhinal cortex (EC), and in the posterior parietal cortex (PPC). Ten minutes prior to testing, the animals received, through the cannulae, 0.5-microliter microinfusions of vehicle (20% dimethylsulfoxide in saline) or of 0.5 microgram of CNQX dissolved in the vehicle. A second test session was carried out 90 min after the first. CNQX blocked retention test performance when given into H + A 1 day after training but not later; when given into EC 1 or 31 days after training, but not later; and when given into PPC 1, 31, or 60 days after training. In all cases performance returned to normal levels in the second test session. The data suggest that H and A are involved in memory expression for only a few days after acquisition; that EC is involved in memory expression for up to 31, but less than 60, days after acquisition; and that PPC is involved in memory expression for up to at least 2 months after acquisition.

Sequential involvement of NMDA receptor-dependent processes in hippocampus, amygdala, entorhinal cortex and parietal cortex in memory processing

Rats bilaterally implanted with cannulae in the CA1 region of the dorsal hippocampus and/or in the amygdaloid nucleus, in the entorhinal cortex, and in the posterior parietal cortex, were trained in a step-down inhibitory avoidance task. At various times after training (immediately, 30, 60 or 90min) they received, through the cannulae, 0.5µl microinfusions of saline or of 5.0µg of AP5 dissolved in saline. A retention test was carried out 24h after training. Retention test performance was hindered by AP5 given into hippocampus, amygdala, or both hippocampus and amygdala immediately but not 30min post-training. The drug was amnestic when given into the entorhinal cortex 30, 60 or 90min after training, or into the parietal cortex 60 or 90min after training, but not at earlier times. The findings suggest a sequential entry in operation, in the post-training period, of NMDA-receptor mediated mechanisms involved in memory processing; first in hippocampus and amygdala, 30min later in entorhinal cortex, and 30min later in posterior parietal cortex.

Distinct positive and negative regulatory elements control neuronal and hepatic transcription of the human transferrin gene

Transferrin (Tf), the iron-transport protein, plays an essential role in the central nervous system development, plasticity, and aging. As a first step toward elucidating the role of each transcription factor involved in the regulation of Tf gene expression, we have recently shown that similar promoter elements direct cell-type specific transcription in oligodendrocytes, epithelial choroid plexus cells, and in the neuronal cell line B103. Here we have analyzed the regulatory elements that control the level of expression of the Tf gene in neuronal cells. Transient expression experiments in B103 cells revealed that the -164/+1 promoter region is stimulated by a position-dependent -1140/-1000 upstream region. DNase I footprinting, gel retardation assays, and antibody reactivity data allowed us to characterize the nuclear factors interacting with this region. The upstream region I-binding protein (URI-BP) belongs to the steroid/retinoid receptor family, while URII-BP is a member of the nuclear factor I (NF-I) family. Interestingly, no enhancer nor silencer activity is detected in B103 cells. This contrasts with our findings in hepatoma cells, where the activity of the -125/+1 promoter can be repressed by a -1000/-819 upstream negative-acting region and stimulated by the -3600/-3300 enhancer. We demonstrate that the negative-acting region presents the characteristics of a silencer that interacts with a nuclear protein present in liver and absent in B103 cells. Similarly, B103 cells lack a nuclear protein able to bind to an essential site of the enhancer. This shows that in B103 cells, the inactivity of the silencer and the enhancer regions results from the absence of at least one essential nuclear protein.

Interactions of the transcription factor AP-1 with the long terminal repeat of different human immunodeficiency virus type 1 strains in Jurkat, glial, and neuronal cells

Human immunodeficiency virus type 1 (HIV-1) infection of the neuronal and astroglial cells of the central nervous system has been proposed to contribute to HIV-1-associated dementia. Recently it was shown that differences in the nucleotide sequence of the long terminal repeat (LTR) of different HIV-1 strains govern the tissue-specific pattern of viral expression. The LTR from central nervous system-derived HIV-1 strains JR-FL and JR-CSF directs expression in the neurons of transgenic mice, in contrast with the lymphotropic LAI strain. By in vitro footprinting, gel retardation, and methylation interference experiments, we have studied the interactions of host cell proteins from human neuronal, glial, HeLa, and Jurkat T cells with the LTRs from the neurotropic JR-FL and JR-CSF strains, compared with the LAI strain. Proteins belonging to the nuclear receptor family bind with different affinities to variant -352 to -324 sites. Gel supershift assays with Jun and Fos antibodies showed that the AP-1 transcription factor present in the various cell types was unable to recognize the -352 to -324 and -306 to -285 AP-1 putative binding sites. Interestingly, Jun and Fos components of AP-1 interact with the variant TGGCTCA sequence located in the -247 to -222 region of both neurotropic strains. These interactions were cell type specific, since they were detected only with extracts from glial and HeLa cells and not from neuronal or Jurkat cells. Cotransfection experiments further revealed that the -247 to -222 sequence is able to mediate AP-1-induced transcriptional activation in glial and not neuronal cells.

Transcription of the human transferrin gene in neuronal cells

We have recently shown that a combination of three transcription factors governs the expression of the human transferrin gene in different brain cell types, oligodendrocytes, choroid plexus cells and neuronal cells. It was essential to elucidate the role of each factor in the regulation of transferrin gene transcription. Site-directed mutagenesis and co-transfection experiments in neuronal cells revealed that chicken ovalbumin upstream promoter transcription factor (COUP-TF), which binds to the promoter region I, acts as a repressor. Overexpression of the CCAAT/enhancer binding protein (C/EBP-alpha), which binds to the promoter region II, transactivates the -164/+1 promoter, even enables the -125/+1 region to promote transcription, and synergistically activates transcription in the presence of CREB. The C/EBP-alpha-mediated activation is antagonized by COUP-TF. The positive action of the cAMP response element-binding protein called CRI-BP is revealed by mutations of the central region I site which repress transcription. Moreover addition of dibutyryl cyclic AMP or overexpression of the catalytic subunit of protein kinase A increase transcription from the wild-type and not from the CRI mutant promoter, which shows that CRI-BP is responsible for mediating cAMP stimulation of Tf gene transcription.

Synapsin IIa bundles actin filaments

Synapsins are neuron-specific phosphoproteins associated with small synaptic vesicles in the presynaptic nerve terminal. Synapsin I, which has been demonstrated to bundle F-actin in vitro, has been postulated to regulate neurotransmitter release by cross-linking synaptic vesicles to the actin cytoskeleton. To investigate the possible interaction of synapsin II with actin filaments, we expressed synapsin II in Spodoptera frugiperda and High Five insect cells using a recombinant baculovirus. Purified recombinant synapsin IIa was incubated with F-actin, and bundle formation was evaluated by light scattering and electron microscopy. Synapsin IIa was found to bundle actin filaments. Dose-response curves indicated that synapsin IIa was more potent than synapsin I in bundling actin filaments. These data suggest that synapsin IIa may cross-link synaptic vesicles and actin filaments in the nerve terminal.

Brain-specific expression of the human transferrin gene. Similar elements govern transcription in oligodendrocytes and in a neuronal cell line

We have identified the regulatory sequences that govern the expression of the human transferrin gene in cultured brain cells and compared them with the data obtained with the neuronal cell line B103. Oligodendrocytes and epithelial choroid plexus cells from rat brain were cultured and used for transient expression experiments. Deletion analysis of 1.8 kilobase pairs of the 5' regulatory sequences revealed a -1530/-1140 positive-acting region in oligodendrocytes. The -164/+1 promoter region was sufficient to confer cell type-specific transcription in oligodendrocytes, epithelial choroid plexus cells, and B103 cells. DNase I footprinting experiments revealed three protected sequences, the proximal regions I and II, and the central region I. Gel retardation and antibody reactivity data allowed us to identify most of the nuclear factors present in oligodendrocytes interacting with the promoter sequences. Chicken ovalbumin upstream promoter transcription factor, a CAAT/enhancer-binding protein, and a cAMP response element-binding protein called CRI-BP interact with the proximal regions I and II and central region I sites, respectively. These data confirm the results obtained with the neuronal cell line and emphasize the importance of the three promoter elements for the transferrin gene-specific expression in the central nervous system compared with only two elements required for liver- and testis-specific expression.

Synapsin IIa accelerates functional development of neuromuscular synapses

We have investigated the possible involvement of the synaptic vesicle protein synapsin IIa in synapse development. Synapsin IIa was introduced into Xenopus embryonic spinal neurons by early blastomere injection, and nerve-muscle cultures were prepared. Synaptic currents were measured by comparing synapses in which the presynaptic neuron either contained [syn IIa (+)] or lacked (control) exogenous synapsin IIa. Syn IIa (+) synapses had a 3.6-fold increase in the frequency and a 2.1-fold increase in the amplitude of spontaneous synaptic currents, compared to controls, after 2 days in culture. Synapsin IIa also increased the amplitude of evoked synaptic currents by 2.3-fold in 2-day cultures. The evoked synaptic current amplitudes of syn IIa (+) synapses had a lower coefficient of variation indicating a more stable evoked response. These enhanced synaptic activities were independent of the presence or absence of the protein in the postsynaptic muscle cell. The findings indicate a role for synapsin IIa in synapse maturation.