A model of cellular dosimetry for macroscopic tumors in radiopharmaceutical therapy.

PURPOSE: In the radiopharmaceutical therapy approach to the fight against cancer, in particular when it comes to translating laboratory results to the clinical setting, modeling has served as an invaluable tool for guidance and for understanding the processes operating at the cellular level and how these relate to macroscopic observables. Tumor control probability (TCP) is the dosimetric end point quantity of choice which relates to experimental and clinical data: it requires knowledge of individual cellular absorbed doses since it depends on the assessment of the treatment's ability to kill each and every cell. Macroscopic tumors, seen in both clinical and experimental studies, contain too many cells to be modeled individually in Monte Carlo simulation; yet, in particular for low ratios of decays to cells, a cell-based model that does not smooth away statistical considerations associated with low activity is a necessity. The authors present here an adaptation of the simple sphere-based model from which cellular level dosimetry for macroscopic tumors and their end point quantities, such as TCP, may be extrapolated more reliably. METHODS: Ten homogenous spheres representing tumors of different sizes were constructed in GEANT4. The radionuclide 131I was randomly allowed to decay for each model size and for seven different ratios of number of decays to number of cells, N(r): 1000, 500, 200, 100, 50, 20, and 10 decays per cell. The deposited energy was collected in radial bins and divided by the bin mass to obtain the average bin absorbed dose. To simulate a cellular model, the number of cells present in each bin was calculated and an absorbed dose attributed to each cell equal to the bin average absorbed dose with a randomly determined adjustment based on a Gaussian probability distribution with a width equal to the statistical uncertainty consistent with the ratio of decays to cells, i.e., equal to Nr-1/2. From dose volume histograms the surviving fraction of cells, equivalent uniform dose (EUD), and TCP for the different scenarios were calculated. Comparably sized spherical models containing individual spherical cells (15 microm diameter) in hexagonal lattices were constructed, and Monte Carlo simulations were executed for all the same previous scenarios. The dosimetric quantities were calculated and compared to the adjusted simple sphere model results. The model was then applied to the Bortezomib-induced enzyme-targeted radiotherapy (BETR) strategy of targeting Epstein-Barr virus (EBV)-expressing cancers. RESULTS: The TCP values were comparable to within 2% between the adjusted simple sphere and full cellular models. Additionally, models were generated for a nonuniform distribution of activity, and results were compared between the adjusted spherical and cellular models with similar comparability. The TCP values from the experimental macroscopic tumor results were consistent with the experimental observations for BETR-treated 1 g EBV-expressing lymphoma tumors in mice. CONCLUSIONS: The adjusted spherical model presented here provides more accurate TCP values than simple spheres, on par with full cellular Monte Carlo simulations while maintaining the simplicity of the simple sphere model. This model provides a basis for complementing and understanding laboratory and clinical results pertaining to radiopharmaceutical therapy.

Identification of GPx8 as a novel cellular substrate of the hepatitis C virus NS3-4A protease

Background: The hepatitis C virus (HCV) NS3-4A protease is not only an essential component of the viral replication complex and a prime target for a ntiviral intervention but also a key player i n the persistence and pathogenesis of HCV. It cleaves and thereby inactivates two crucial adaptor proteins in viral RNA sensing and innate immunity (MAVS and TRIF) as well as a phosphatase involved in growth factor signaling (TCPTP). T he aim of this study was to identify novel cellular substrates o f the N S3-4A protease and to investigate their role in the replication and pathogenesis of HCV. Methods: Cell lines inducibly expressing t he NS3-4A protease were analyzed in basal as well as interferon-α-stimulated states by stable isotopic l abeling using amino acids in cell culture (SILAC) coupled with protein separation and mass spectrometry. Candidates fulfilling stringent criteria for potential substrates or products of the NS3-4A protease were further i nvestigated in different experimental systems as well a s in liver biopsies from patients with chronic hepatitis C. Results: SILAC coupled with protein separation and mass spectrometry yielded > 5000 proteins of which 18 candidates were selected for further analyses. These allowed us to identify GPx8, a membrane-associated peroxidase involved in disulfide bond formation in the endoplasmic reticulum, as a n ovel cellular substrate of the H CV NS3-4A protease. Cleavage occurs at cysteine in position 11, removing the cytosolic tip of GPx8, and was observed in different experimental systems as well as in liver biopsies from patients with chronic hepatitis C. Further functional studies, involving overexpression and RNA silencing, revealed that GPx8 is a p roviral factor involved in viral particle production but not in HCV entry or HCV RNA replication. Conclusions: GPx8 is a proviral host factor cleaved by the HCV NS3-4A protease. Studies investigating the consequences of GPx8 cleavage for protein function are underway. The identification of novel cellular substrates o f the HCV N S3-4A protease should yield new insights i nto the HCV life cycle and the pathogenesis of hepatitis C and may reveal novel targets for antiviral intervention.

Cellular perspectives on the glutamate-monoamine interactions in limbic lobe structures and their relevance for some psychiatric disorders.

Dopaminergic, serotonergic and noradrenergic nuclei form the trimonoamine modulating system (TMMS). This system modulates emotional/motivational activities mediated by the limbic circuitry, where glutamate is the major excitatory neurotransmitter. Two main concepts are the basis of this review. First, since 1950 and the discovery of the antipsychotic activity of the dopamine D2 receptor antagonist chlorpromazine, it appears that drugs that can modulate the TMMS possess therapeutic psychiatric properties. Second, the concept of glutamate/trimonoamine imbalance in the cortico-striato-thalamo-cortical loop that has been so successful in explaining the pathophysiology of Parkinson disease has been applied in the pathophysiology of schizophrenia. This review will focus on the complex interactions between the fast synaptic glutamatergic transmission and the TMMS in specific parts of the limbic lobe and we will try to link these interactions to some psychiatric disorders, mainly depression, schizophrenia and drug addiction.

Endogenous cannabinoid receptor CB1 activation promotes vascular smooth-muscle cell proliferation and neointima formation.

Percutaneous transluminal angioplasty is frequently used in patients with severe arterial narrowing due to atherosclerosis. However, it induces severe arterial injury and an inflammatory response leading to restenosis. Here, we studied a potential activation of the endocannabinoid system and the effect of FA amide hydrolase (FAAH) deficiency, the major enzyme responsible for endocannabinoid anandamide degradation, in arterial injury. We performed carotid balloon injury in atherosclerosis-prone apoE knockout (apoE(-/-)) and apoE(-/-)FAAH(-/-) mice. Anandamide levels were systemically elevated in apoE(-/-) mice after balloon injury. ApoE(-/-)FAAH(-/-) mice had significantly higher baseline anandamide levels and enhanced neointima formation compared with apoE(-/-) controls. The latter effect was inhibited by treatment with CB1 antagonist AM281. Similarly, apoE(-/-) mice treated with AM281 had reduced neointimal areas, reduced lesional vascular smooth-muscle cell (SMC) content, and proliferating cell counts. The lesional macrophage content was unchanged. In vitro proliferation rates were significantly reduced in CB1(-/-) SMCs or when treating apoE(-/-) or apoE(-/-)FAAH(-/-) SMCs with AM281. Macrophage in vitro adhesion and migration were marginally affected by CB1 deficiency. Reendothelialization was not inhibited by treatment with AM281. In conclusion, endogenous CB1 activation contributes to vascular SMC proliferation and neointima formation in response to arterial injury.

Inhibition of death receptor signals by cellular FLIP.

The widely expressed protein Fas is a member of the tumour necrosis factor receptor family which can trigger apoptosis. However, Fas surface expression does not necessarily render cells susceptible to Fas ligand-induced death signals, indicating that inhibitors of the apoptosis-signalling pathway must exist. Here we report the characterization of an inhibitor of apoptosis, designated FLIP (for FLICE-inhibitory protein), which is predominantly expressed in muscle and lymphoid tissues. The short form, FLIPs, contains two death effector domains and is structurally related to the viral FLIP inhibitors of apoptosis, whereas the long form, FLIP(L), contains in addition a caspase-like domain in which the active-centre cysteine residue is substituted by a tyrosine residue. FLIPs and FLIP(L) interact with the adaptor protein FADD and the protease FLICE, and potently inhibit apoptosis induced by all known human death receptors. FLIP(L) is expressed during the early stage of T-cell activation, but disappears when T cells become susceptible to Fas ligand-mediated apoptosis. High levels of FLIP(L) protein are also detectable in melanoma cell lines and malignant melanoma tumours. Thus FLIP may be implicated in tissue homeostasis as an important regulator of apoptosis.

Cellular distribution of Hsp70 expression in rat skeletal muscles. Effects of moderate exercise training and chronic hypoxia.

Rat hindlimb muscles constitutively express the inducible heat shock protein 72 (Hsp70), apparently in proportion to the slow myosin content. Since it remains controversial whether chronic Hsp70 expression reflects the overimposed stress, we investigated Hsp70 cellular distribution in fast muscles of the posterior rat hindlimb after (1) mild exercise training (up to 30 m/min treadmill run for 1 h/day), which induces a remodeling in fast fiber composition, or (2) prolonged exposure to normobaric hypoxia (10%O(2)), which does not affect fiber-type composition. Both conditions increased significantly protein Hsp70 levels in the skeletal muscle. Immunohistochemistry showed the labeling for Hsp70 in subsets of both slow/type 1 and fast/type 2A myofibers of control, sedentary, and normoxic rats. Endurance training increased about threefold the percentage of Hsp70-positive myofibers (P < 0.001), and changed the distribution of Hsp70 immunoreactivity, which involved a larger subset of both type 2A and intermediate type 2A/2X myofibers (P < 0.001) and vascular smooth muscle cells. Hypoxia induced Hsp70 immunoreactivity in smooth muscle cells of veins and did not increase the percentage of Hsp70-positive myofibers; however, sustained exposure to hypoxia affected the distribution of Hsp70 immunoreactivity, which appeared detectable in a very small subset of type 2A fibers, whereas it concentrated in type 1 myofibers (P < 0.05) together with the labeling for heme-oxygenase isoform 1, a marker of oxidative stress. Therefore, the chronic induction of Hsp70 expression in rat skeletal muscles is not obligatory related to the slow fiber phenotype but reveals the occurrence of a stress response.

Antibody-mediated and cellular immune responses induced in naive volunteers by vaccination with long synthetic peptides derived from the Plasmodium vivax circumsporozoite protein.

Plasmodium vivax circumsporozoite (CS) protein is a leading malaria vaccine candidate. We describe the characterization of specific immune responses induced in 21 malaria-naive volunteers vaccinated with long synthetic peptides derived from the CS protein formulated in Montanide ISA 720. Both antibody- and cell-mediated immune responses were analyzed. Antibodies were predominantly of IgG1 and IgG3 isotypes, recognized parasite proteins on the immunofluorescent antibody test, and partially blocked sporozoite invasion of hepatoma cell lines in vitro. Peripheral blood mononuclear cells from most volunteers (94%) showed IFN-γ production in vitro upon stimulation with both long signal peptide and short peptides containing CD8+ T-cell epitopes. The relatively limited sample size did not allow conclusions about HLA associations with the immune responses observed. In summary, the inherent safety and tolerability together with strong antibody responses, invasion blocking activity, and the IFN-γ production induced by these vaccine candidates warrants further testing in a phase II clinical trial.

Les complications de la cirrhose hépatique: varices oesophagiennes, ascite et carcinome hépato-cellulaire [Complications of liver cirrhosis: oesophageal varices, ascites and hepato-cellular carcinoma]

The principal treatment for bleeding oesophageal varices is endoscopic ligation. Non-cardioselective beta-blockers are the gold-standard of primary prophylaxis. The principal treatment for ascites is a salt-free diet and diuretics, mainly spironolactone, if necessary associated with a loop diuretic. In refractory ascites, paracentesis or installation of a transjugular intrahepatic portosystemic shunt (TIPS) are two possible treatment options. Cirrhosis patients are at higher risk of developing hepato-cellular carcinoma. Surgery is only possible in a small number of cases. Percutaneous destruction techniques have nearly the same survival rate as that obtained by surgery and should be proposed to patients where surgery is not an option.

Organisation and role of actin microfilaments during cellular growth and morphogenesis in the moss Physcomitrella patens

ABSTRACT The network of actin cytoskeleton is composed of actin filaments (F-actin) that are made by polymerisation of actin monomers and actin binding proteins. It is required for growth and morphogenesis of eukaryotic cells. The labelling of F-actin with constitutively expressed GFP-Talin (Kost et al., 1998) reveals the organisation of cellular actin networks in plants. Due to the lack of information on actin cytoskeleton through gametophytic development of the model moss plant Physcornitrella patens, stable transgenic lines overexpressing GFP-Talin were generated to detect F-actin structures. It is shown that the 35S promoter driven expression is not suitable for F-actin labelling in all cells. When it is replaced by the inducible heat-shock promoter Gmhsp17.3 from soybean, one hour mild heat stress at 37°C followed by recovery at 25°C is enough to induce efficient and transient labelling in all tissues without altering cellular morphology. The optimal observations of F-actin structures at different stages of moss development can be done between 12-18 hours after the induction. By using confocal microscopy, we demonstrate that stellated actin arrays were densely accumulated at the growing tip in regenerating protoplasts, apical protonemal cells and rhizoids and connected with a fine dispersed F-actin mesh. Following three-dimensional growth, the cortical star-like structures are widespread in the meristematic cells of developing bud and young gametophores. On the contrary, undulating networks of actin cables are found at the final stage of cell differentiation. During redifferentiation of mature leaf cells into protonemal filaments the rather stagnant web of actin cables is replaced by diffuse actin meshwork. In eukaryotes, nucleation of the actin monomers prior to their polymerization is driven by the seven-subunit ARP2/3 complex and formins. We cloned the gene encoding the ARP3 subunit of P. patens and generated arp3 mutants of the moss through gene disruption. The knockout of ARP3 affects the elongation of chloronemal cells and blocks further differentiation of caulonemal cells and rhizoids, and the gametophores are slightly stunted compared to wild-type. The arp mutants were created in the heat-shock inducible GFP-Talin strains allowing us to visualise a disorganised actin network and a lack of star-like actin cytoskeleton arrays. We conclude that ARP2/3 dependent nucleation of actin filaments is critical for the growth of filamentous cells, which in turn influences moss colonization. In complementation assays, the overexpression of Physcomitrella and Arab idopsis ARP3 genes in the moss arp3 mutant results in full recovery of wild type phenotype. In contrast the ARP3 subunit of fission yeast is not able to complement the moss arp3 mutant of moss indicating that regulation of the ARP2/3 dependent actin nucleation diverged in different kingdoms. RESUME Le réseau d'actine est composé de filaments de F-actine et d'un ensemble de protéines s'y attachant (Actin binding proteins). Le réseau d'actine est nécessaire à la croissance et à la morphogenèse de toutes les cellules eucaryotes. Chez les plantes, le marquage ainsi que l'étude de l'organisation du réseau d'actine ont été réalisés en utilisant une fusion GFP-Talin (Kost et al., 1998) exprimée sous le control d'un promoteur constitutif. Afin d'étudier les structures F-actine dans les cellules de Physcomitrella Patens et pour combler le manque d'information sur le développement des gamétophores, des lignées transgéniques stables surexprimant GFP-Talin ont été crées. Nous avons démontré que l'utilisation du promoteur 35S est inadéquate pour le marquage complet et homogène des filaments d'actine dans toutes les cellules de P. patens. Par contre, l'utilisation du promoteur inductible Gmhsp17.3 nous a permis de réaliser un marquage transitoire et général dans tous les tissus de la mousse. Une heure de choc thermique à 37°C suivis d'un temps de récupération de 12-18h à 25°C sont les conditions optimales (sans dommages cellulaires) pour l'observation des structures F-actine à différentes étapes de développement de la mousse. En utilisant la microscopie confocale, nous avons observé l'existence de structures F-actine accumulées en forme d'étoiles. Ces structures, qui sont liées au réseau de microfilaments d'actine, ont été observées dans les protoplastes en régénération, les cellules des protonema apicales ainsi que dans les rhizoïdes. En suivant la croissance tridimensionnelle, ces structures en étoiles ont été observées dans les cellules meristématiques des bourgeons et des jeunes gamétophores. Par contre, dans les cellules différentiées ces structures laissent place à des réseaux de câbles épais. Nous avons également remarqué que durant la redifferentiation des cellules foliaires le réseau de câbles de F-actine est remplacé par un réseau de F-actine diffus. Dans les cellules eucaryotes, la nucléation des filaments d'actirie précédant leur polymérisation est contrôlé par sept sous unités du complexe ARP2/3 et par des formines. Nous avons isolé le gène codant pour la sous unité ARP3 de P. patens et nous avons crée des mutants arp3 par intégration ciblée (Knockout). L'élongation des cellules chloronema est clairement affectée dans les mutants arp3. La différentiation des caulonemata et des rhizoïdes est bloquée et les gametophores sont légèrement plus courts comparé au type sauvage. A fin d'étudier l'organisation des filaments d'actines dans les mutants arp3, nous avons aussi réalisé un arp3-knockout dans la lignée Hsp-GFP-Talin. La nouvelle lignée générée nous a permis de visualiser une désorganisation du réseau d'actine et une absence complète de structures de F-actine accumulée en forme d'étoiles. Les résultats obtenus nous amènent à conclure que la nucléation (ARP2/3 dépendante) des filaments d'actine est indispensable à la croissance des cellules filamenteuses. Par conséquent, les filaments d'actine semblent avoir un rôle dans la colonisation des milieux par les mousses. Nous avons également procédé à des essais de complémentation du mutant arp3. La surexpression des gènes ARP3 de Physcomitrella et d'Arabidopsis dans les cellules du mutant arp3 rétabli complètement le phénotype WT. Par contre, le gène ARP3 des levures n'est pas suffisant pour complémenter la même mutation dans les cellules de mousses. Ce résultat démontre que les mécanismes de régulation de la nucléation des filaments d'actine (ARP2/3 dépendante) sont différents entre les différents groupes d'eucaryotes.

The function of a new regulator of epidermal differentiation, HOP, and pathomechanisms underlying epidermolytic hyperkeratosis

The process of epidermal differentiation involves proliferation, differentiation, migration and maturation of keratinocytes to form an impermeable barrier against water loss and outside environment. It is controlled by highly balanced regulatory machinery, involving many molecules that are still under investigation.Homeobox proteins are involved in body patterning and morphogenesis of organs and are studied as potentially good candidates to regulate this process. In the first project we investigated the role of a protein named HOP which belongs to a group of homeobox proteins. Even if HOP is a small protein almost completely composed of the homeodomain and without DNA binding capacity, it is considered as transcriptional regulator in different tissues. HOP interacts with serum response factor (SRF) and histone deacetylase type 2 (HDAC2). By microarray analysis we found that HOP expression increases in cultured human primary keratinocytes (NHK) which undergo calcium-induced differentiation. HOP protein was localized in granular layer of the epidermis of healthy individuals. Lack of HOP was demonstrated in psoriatic lesions, whereas a strong expression was demonstrated in the lesional skin of patients affected with lichen planus (LP). Since LP is characterized by hypergranulosis while psoriatic lesions by progressive lack of the granular layer, the obtained data indicated that HOP might have a potential function in granular layer of epidermis. To investigate HOP function, we inhibited its expression by using HOP specific StealthRNAi and we overexpressed HOP using lentiviral vectors in differentiating NHK. The conclusion of both experiments indicated that HOP positively regulates the expression of late differentiation markers, such as profilaggrin, loricrin and transglutaminase 1. The in vitro data were next confirmed in vivo using HOP knockout mouse model.The second part of my study involved analysis of mechanisms underlying the pathogenesis of epidermolytic hyperkeratosis (EHK). EHK is a genetic disorder characterized by erythema, skin blistering, keratinocyte hyperproliferation and hyperkeratosis. EHK is caused by mutations in keratin 1 or 10 (K1, K10) which are major structural proteins of differentiated keratinocytes and participate in the cellular scaffold formation. To investigate how the structural proteins carrying mutations alter cellular signaling, we established an in vitro model for EHK by overexpression of one of the most common K10 mutations reported so far (K10R156H), in primary human keratinocytes. In order to mimic the in vivo situation, mutated keratinocytes growing on silicone membranes were subjected to mechanical stretch. We observed strong collapse of KIF in K10R156H keratinocytes when subjected to stretch for 30 minutes. Our data demonstrated stronger activation of p38, a member of MAPK stress signaling pathways, in K10R156H when compared to control cells. We demonstrated also that K10R156H keratinocytes showed an induction of TNF-α and RANTES release in response to stretch.Taken together these studies characterize a novel regulator of epidermal differentiation - HOP and demonstrate new aspects implicated in the pathogenesis of EHK.

P16 Mediated Suppression Of Telomerase In Normal And Malignant Human Breast Cells.

Summary The cyclin-dependent kinase inhibitor p16(INK4a) (CDKN2A) is an important tumor-suppressor gene frequently inactivated in human tumors. p16 suppresses the development of cancer by triggering an irreversible arrest of cell proliferation termed cellular senescence. Here, we describe another anti-oncogenic function of p16 in addition to its ability to halt cell cycle progression. We show that transient expression of p16 stably represses the hTERT gene, encoding the catalytic subunit of telomerase, in both normal and malignant breast epithelial cells. Short-term p16 expression increases the amount of histone H3 trimethylated on lysine 27 (H3K27) bound to the hTERT promoter, resulting in transcriptional silencing, likely mediated by polycomb complexes. Our results indicate that transient p16 exposure may prevent malignant progression in dividing cells by irreversible repression of genes, such as hTERT, whose activity is necessary for extensive self-renewal.

The inhibition of fat cell proliferation by n-3 fatty acids in dietary obese mice.

ABSTRACT: BACKGROUND: Long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) of marine origin exert multiple beneficial effects on health. Our previous study in mice showed that reduction of adiposity by LC n-3 PUFA was associated with both, a shift in adipose tissue metabolism and a decrease in tissue cellularity. The aim of this study was to further characterize the effects of LC n-3 PUFA on fat cell proliferation and differentiation in obese mice. METHODS: A model of inducible and reversible lipoatrophy (aP2-Cre-ERT2 PPARgammaL2/L2 mice) was used, in which the death of mature adipocytes could be achieved by a selective ablation of peroxisome proliferator-activated receptor gamma in response to i.p. injection of tamoxifen. Before the injection, obesity was induced in male mice by 8-week-feeding a corn oil-based high-fat diet (cHF) and, subsequently, mice were randomly assigned (day 0) to one of the following groups: (i) mice injected by corn-oil-vehicle only, i.e."control" mice, and fed cHF; (ii) mice injected by tamoxifen in corn oil, i.e. "mutant" mice, fed cHF; (iii) control mice fed cHF diet with 15% of dietary lipids replaced by LC n-3 PUFA concentrate (cHF+F); and (iv) mutant mice fed cHF+F. Blood and tissue samples were collected at days 14 and 42. RESULTS: Mutant mice achieved a maximum weight loss within 10 days post-injection, followed by a compensatory body weight gain, which was significantly faster in the cHF as compared with the cHF+F mutant mice. Also in control mice, body weight gain was depressed in response to dietary LC n-3 PUFA. At day 42, body weights in all groups stabilized, with no significant differences in adipocyte size between the groups, although body weight and adiposity was lower in the cHF+F as compared with the cHF mice, with a stronger effect in the mutant than in control mice. Gene expression analysis documented depression of adipocyte maturation during the reconstitution of adipose tissue in the cHF+F mutant mice. CONCLUSION: Dietary LC n-3 PUFA could reduce both hypertrophy and hyperplasia of fat cells in vivo. Results are in agreement with the involvement of fat cell turnover in control of adiposity.

Molecular crime and cellular punishment: active detoxification of misfolded and aggregated proteins in the cell by the chaperone and protease networks.

Labile or mutation-sensitised proteins may spontaneously convert into aggregation-prone conformations that may be toxic and infectious. This hazardous behavior, which can be described as a form of "molecular criminality", can be actively counteracted in the cell by a network of molecular chaperone and proteases. Similar to law enforcement agents, molecular chaperones and proteases can specifically identify, apprehend, unfold and thus neutralize "criminal" protein conformers, allowing them to subsequently refold into harmless functional proteins. Irreversibly damaged polypeptides that have lost the ability to natively refold are preferentially degraded by highly controlled ATP-consuming proteases. Damaged proteins that escape proteasomal degradation can also be "incarcerated" into dense amyloids, "evicted" from the cell, or internally "exiled" to the lysosome to be hydrolysed and recycled. Thus, remarkable parallels exist between molecular and human forms of criminality, as well as in the cellular and social responses to various forms of crime. Yet, differences also exist: whereas programmed death is the preferred solution chosen by aged and aggregation-stressed cells, collective suicide is seldom chosen by lawless societies. Significantly, there is no cellular equivalent for the role of familial care and of education in general, which is so crucial to the proper shaping of functional persons in the society. Unlike in the cell, humanism introduces a bias against radical solutions such as capital punishment, favouring crime prevention, reeducation and social reinsertion of criminals.

Macrophage migration inhibitory factor is critically involved in basal and fluoxetine-stimulated adult hippocampal cell proliferation and in anxiety, depression, and memory-related behaviors.

Intensive research is devoted to unravel the neurobiological mechanisms mediating adult hippocampal neurogenesis, its regulation by antidepressants, and its behavioral consequences. Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine that is expressed in the CNS, where its function is unknown. Here, we show, for the first time, the relevance of MIF expression for adult hippocampal neurogenesis. We identify MIF expression in neurogenic cells (in stem cells, cells undergoing proliferation, and in newly proliferated cells undergoing maturation) in the subgranular zone of the rodent dentate gyrus. A causal function for MIF in cell proliferation was shown using genetic (MIF gene deletion) and pharmacological (treatment with the MIF antagonist Iso-1) approaches. Behaviorally, genetic deletion of MIF resulted in increased anxiety- and depression-like behaviors, as well as of impaired hippocampus-dependent memory. Together, our studies provide evidence supporting a pivotal function for MIF in both basal and antidepressant-stimulated adult hippocampal cell proliferation. Moreover, loss of MIF results in a behavioral phenotype that, to a large extent, corresponds with alterations predicted to arise from reduced hippocampal neurogenesis. These findings underscore MIF as a potentially relevant molecular target for the development of treatments linked to deficits in neurogenesis, as well as to problems related to anxiety, depression, and cognition.

Different antigen-presenting cells differ in their capacity to induce lymphokine production and proliferation of an apo-cytochrome c-specific T cell clone.

The activation of an apo-cytochrome c-specific T cell clone was found to differ, depending on the antigen-presenting cell population. Whereas total syngeneic spleen cells and bone marrow macrophages could be shown to trigger proliferation, IL 2, and MAF production by the T cell clone, a B cell lymphoma only induced MAF secretion. Further studies demonstrated that this effect was not due to a different antigen processing by the B lymphoma or to limiting amounts of Ia and antigen molecules on the B lymphoma cell surface. The dissociation of induction of MAF production from IL-2 production/proliferation found with the different antigen-presenting cells indicates strongly that molecules other than Ia and antigen may be required for the complete functional activation of antigen-specific T cell clones.