Le temps dans le système immunitaire
publicité
Le temps dans la réponse immunitaire M1 Immunologie Cellule dendritique Lymphocytes Le temps dans la réponse immunitaire Le temps dans le système immunitaire Quels sont les changements opérés dans ce système dans l’ontogénie d’un organisme ? Visualisations de l’étude des changements du système immunitaire en fonction de l’ontogénie Ontogénie 1 Système immunitaire Reproduction 2 Adulte Stade mature Oeuf Adulte Système immunitaire X Stade immature Visualisations de l’étude des changements du système immunitaire en fonction de l’ontogénie Ontogénie 1 Système immunitaire Reproduction 2 Adulte Stade mature Oeuf Adulte Système immunitaire X Stade immature Visualisations de l’étude des changements du système immunitaire en fonction de l’ontogénie Ontogénie 1 Système immunitaire Reproduction 2 Adulte Stade mature Oeuf Adulte Système immunitaire X Stade immature Visualisations de l’étude des changements du système immunitaire en fonction de l’ontogénie Ontogénie 1 Système immunitaire Reproduction 2 Adulte Stade mature Oeuf Adulte Système immunitaire X Stade immature Identification des stades de l’ontogénie permettant de relater les changements dans le système immunitaire 3 Ontogénie Œuf Maturité sexuelle Stade immature Stade mature Maturité sexuelle Système immunitaire Mort ? Vieillissement ? ? Identification des stades de l’ontogénie permettant de relater les changements dans le système immunitaire 3 Ontogénie Œuf Maturité sexuelle Stade immature Stade mature Maturité sexuelle Système immunitaire Mort ? Vieillissement ? ? Différencier la réponse immunitaire des changements engendrés par une rupture développementale dans le système immunitaire Réponse immune = Changements dans le système Activation/Migration cellulaire Sécrétions cytokiniques Inflammation Coagulation Mélanisation ≠ Détection d’un épitope immunogène Tolérance/ Élimination État 1 État 2 Hormones Système immunitaire Les ruptures de l’ontogénie... Le comparatif des événements entre embryon et puberté Similitudes • Neurogenèse • Formation des synapses • Plasticité • Myélinisation • Différenciation des monocytes du sac vitellin • Acquisition de la microglie • Restructuration de l’arbre synaptique par croissance et mort neuronale La puberté et la système immunitaire Puberté Œuf Maturité sexuelle Stade immature Stade mature Quels changements? Système immunitaire Le rôle de la microglie London et al. Macrophage heterogeneity within the CNS Population cellulaire constituée de macrophages peuplant le système nerveux central. factors associated with remyelination (h) and support regeneration (i). FIGURE 1 | microglial and mo-MΦ functions – cascade of events. Microglie etthat macrophages, la cascade des événements. Intensive acute or chronic activation renders microglia neurotoxic; under such (a) Resident microglia originate from yolk sac macrophages repopulate London et al,Microglia monocyte-derived macrophages: functionally that act infail concert in CNS plasticity and repair, 2013. Instead, conditions microglia to acquire a neuroprotective phenotype. CNS parenchyma duringand early development and are self-renewed locally, distinct populations these cells produce reactive oxygen species (ROS), nitric oxide (NO), independent from bone marrow-derived monocytes, by proliferation of proteases, and pro-inflammatory cytokines such as IL-1, IL-6, and TNF-α, all of primitive progenitors. (b) In the steady state microglia are constantly scanning their environment through their highly motile processes. These which endanger neuronal activity (j). Microglial malfunction results in the cells facilitate the maintenance of synapses (c) and neurogenesis (d), recruitment of mo-MΦ to the damage site (k). mo-MΦ secrete 92 M.K. Holder, J.D. Blaustein / Frontiers in Neuroendocrinology 35 (2014) 89–110 À la puberté Fig. 2. Representation of the hypothalamus–pituitary–gonadal axis. Neurons in the preoptic area and mediobasal hypothalamus secrete gonadotropin-releasing hormone Holder et aBlaustein, Puberty adolescence as aoftime of vulnerability stressors that alter 2013 (GnRH), neurohormone, into the and hypophyseal portal system the median eminence. The to portal blood carries GnRH into neurobehavrioal the pituitary gland andprocesses, activates its receptor, gonadotropin-releasing hormone receptor (GnRHR) located on gonadotrope cells. Once activated, the GnRHR triggers synthesis and secretion of pituitary gonadotropins: follicle stimulating hormone (FSH) and luteinizing hormone (LH). LH and FSH then act in concert to stimulate the production of gonadal steroid hormones (e.g., androgens from the testes and estrogens and progestins from the ovary) and maturation of gametes (e.g., the spermatozoa in the testes and an ovum in the ovary). The gonadal hormones act in the hypothalamus and pituitary to regulate gonadotropin secretion via feedback loops. Solid lines, positive feedback; dashed lines, negative feedback. Puberté Maturité sexuelle results in profound alterations in physiology and behavior as indithe brain: estrogen receptor (ER) a and b, also referred to as Œuf cated by (I) increases in anxiety and depression (Ge et al., 2001; Patton and Viner, 2007); (II) risk-taking and novelty-seeking behaviors (Arnett, 1996; Roberti, 2004; Wagner, 2001); (III) alterations in learning and cognition (Im-Bolter et al., 2013); and (IV) drug and alcohol use and abuse (Bekman et al., 2010; Crawford et al., 2003; MacPherson et al., 2010). In this review, we will confine ourselves to the ability of stressors in the pubertal and adolescent periods to alter the brain’s response to gonadal (Section 3) and adrenal (Section 4) hormones. Stade immature 3. Gonadal steroid hormones 3.1. Hypothalamic–pituitary–gonadal (HPG) axis Augmentation de la substance grise dans le lobe frontal The hypothalamus and preoptic areas of the brain control much of the neuroendocrine activity of vertebrates via regulation of hormone secretion. The secretion of the gonadal hormones, primarily estrogens and progestins in females and androgens in males, is controlled by the HPG axis (Fig. 2). The primary sources of gonadal hormones are the ovaries in females and the testes in males. The ESR1 and ESR2, respectively. High levels of ERa are present in hypothalamic and limbic nuclei in the rat brain, including but not limited to the anteroventral periventricular nucleus (AVPV), medial preoptic area (mPOA), bed nucleus of the stria terminalis (BNST), arcuate nucleus, paraventricular nucleus of the hypothalamus (PVN), ventromedial nucleus of the hypothalamus (VMN), and medial amygdala (MeA) (Shughrue et al., 1996, 1997). The distribution of ERb is similar to ERa, but it is more highly expressed in the mPOA, hippocampus, and cerebellum (Shughrue et al., 1996, 1997). While no qualitative sex differences in the distribution of ERs in particular brain regions have been reported, there are sex differences in the density of ERs (Rainbow et al., 1982). Compared to male rats, female rats have higher concentrations of ERs in the BNST peri-pubertally (Kuhnemann et al., 1994) and in the mPOA, AVPV, and VMN pubertally and into adulthood (Brown et al., 1988; Kuhnemann et al., 1994). Specifically, female rats have a higher density of ERa in the VMN during pubertal development (Yokosuka et al., 1997) and in adulthood (Yamada et al., 2009) and more ERb in the lateral amygdaloid nucleus and the dentate gyrus and CA3 region of the hippocampus in adulthood (Zhang Stade mature Diminution de la substance grise dans le lobe frontal Conclusions sur la puberté Puberté Œuf Maturité sexuelle Stade immature Activation de la microglie via les changements hormonaux Stade mature Restructuration des substances grise et blanche : changement comportemental Système immunitaire ACTIVATION DES MACROPHAGES DE LA MICROGLIE La grossesse Grossesse et système immunitaire Grossesse Œuf Stade immature Stade mature Quels changements? Système immunitaire La grossesse : vers un état anti-inflammatoire Grossesse Œuf Maturité sexuelle Stade immature Stade mature Robinson and Klein Page 20 Figure 1. Balance entrethe les three réponses inflammatoires et anti-inflammatoires les troisoftrimestres de la grossesse, During trimesters of pregnancy, there is a shift pendant in the balance proinflammatory Robinson et Klein, Pregnancy and pregnancy-associated hormones alter immune responses and disease pathogenesis, 2012. and anti-inflammatory responses. By the third trimester, anti-inflammatory responses, La grossesse : vers un état anti-inflammatoire Grossesse P4 Œuf Maturité sexuelle Cytokines anti-inflammatoires PIBF PIBF TCD4+ PIBF TCD4+ PIBF PIBF PIBF PIBF PIBF PIBF PIBF TCD4+ PIBF PIBF TH1 PIBF PIBF PIBF TH2 L’induction de la tolérance Interface fœto-maternelle Th1 IL-10 Th2 Th1 hCG IL4 Th1 Tregs Blastocyste Tr1 Tregs Th2 Th2 Th1 Th2 Tregs Th2 Th2 Th2 Th1 Th2 Th1 Th2 Th2 Th1 Inspiré de Gregori, HLA-G orchestrates the early interaction of human trophoblasts with the maternal niche, 2015 Schumacker et al, Human Chorionic Gonadotropin Attracts Regulatory T Cells into the Fetal-Maternal Interface during Early Human Pregnancy, 2009 Th2 Généralisations sur la grossesse et le système immunitaire de la mère Grossesse Œuf Maturité sexuelle Les hormones sont détectées par les récepteurs présents sur les cellules immunitaires Système immunitaire Développement de l’embryon TOLERANCE ÉTAT ANTI-INFLAMMATOIRE La vieillesse Le vieillissement dans l’ontogénie : indépendance ou non de la maturité sexuelle ? Œuf 1 Maturité sexuelle Stade immature Mort Stade mature Vieillissement Œuf Maturité sexuelle Stade immature 2 ? Vieillissement ? Stade mature Vieillissement Maturité sexuelle Œuf Stade immature Stade mature 3 Vieillissement ? Le vieillissement dans l’ontogénie : indépendance ou non de la maturité sexuelle ? Œuf 1 Maturité sexuelle Stade immature Mort Stade mature Vieillissement Œuf Maturité sexuelle Stade immature 2 ? Vieillissement ? Stade mature Vieillissement Maturité sexuelle Œuf Stade immature Stade mature 3 Vieillissement ? Le vieillissement dans l’ontogénie : indépendance ou non de la maturité sexuelle ? Œuf 1 Maturité sexuelle Stade immature Mort Stade mature Vieillissement Œuf Maturité sexuelle Stade immature 2 ? Vieillissement ? Stade mature Vieillissement Maturité sexuelle Œuf Stade immature Stade mature 3 Vieillissement ? Le vieillissement dans l’ontogénie : indépendance ou non de la maturité sexuelle ? Œuf 1 Maturité sexuelle Stade immature Mort Stade mature Vieillissement Œuf Maturité sexuelle Stade immature 2 ? Vieillissement ? Stade mature Vieillissement Maturité sexuelle Œuf Stade immature Stade mature 3 Vieillissement ? Le vieillissement et le système immunitaire Œuf Maturité sexuelle Stade immature Mort Stade mature Vieillissement Vieillissement ? Système immunitaire ? Les phénotypes de la vieillesse Stade immature Stade mature Inflammation M.R. Gubbels Bupp / Cellular Immunology 294 (2015) 102–110 107 Table 1 Summary of aging-related immune phenotypes experienced in males and females. Immune phenotype Innate NK cell numbers Monocytes IL-6 production (LPS) TNF-a production (LPS) IP-10 production (IFN-c) Serum concentrations of C-reactive protein IL-6 TNF-a IL-10 Adaptive B cell numbers T cell numbers Proliferative capacity IL-2 production (anti-CD3 + antiCD28) IFN-c production (anti-CD3 + antiCD28) IFN-c production (IL-18 + IL-12) IL-17 production (anti-CD3 + antiCD28) CD8+ CD28" (TEMRA) Inverted CD4/8 ratio CD4+ overall Mucosal associated invariant T cells Sex-specific change with age Species & age Refs. " In both, but more dramatic " in F Humans ! 60 years old [105] No change in either M or F with age No change in either M or F with age ; In both, but more dramatic ; in M Healthy humans ! 65 years old Healthy humans ! 65 years old Healthy humans ! 65 years old [108] [108] [108] " In M, study) " In M, study) " In M, study) ; In M, " in F (M & F not compared in same Humans ! 60 years old [69,119] " in F (M & F not compared in same Males ! 60 years old; females postmenopause or ! 60 years old Males ! 60 years old; females postmenopause or ! 60 years old Humans ! 60 years old [69,118,119] Humans ! 66 years old Humans ! 66 years old Humans ! 66 years old Healthy humans ! 65 years Mice 15 & 23 months old Healthy humans ! 65 years Mice 23 months old Healthy humans ! 65 years Healthy humans ! 65 years [105,107] [105,107] [105,107] [108] [13] [108] [13] [108] [108] ; ; ; ; ; ; " ; ; In In In In In In In In In " in F (M & F not compared in same no change in F both, but more dramatic both, but more dramatic both, but more dramatic both both, but more dramatic M but " in F F, but no change in M both, but more dramatic M but no change in F ; in M ; in M ; in M ; in F ; in M " In both, but more dramatic " in M Both, but more prevalent in M ; In both, but more dramatic ; in M ; In both, but more dramatic ; in M old old old old Healthy humans 20–90 years old Humans ! 66 years old Humans ! 66 years old Humans ! 60 years old Sommaire de phénotypes liés à l’age chez les femelles et les mâles (souris et humains) Melanie and Gubbels Bupp_Sex, the aging immune system, and chronic disease,2015 express estrogen and androgen receptors as well as aromatase, the enzyme that converts androgens to estrogens [45]. Estrogen signal- References [69,118,119] [69] [105] [107] [8,107] [106] L’inflamm-aging Stade immature Stade mature Vieillissement FRANCESCHI et al.: INFLAMM-AGING Système immunitaire Franceshi, Inflamm-aging, Inflammation 249 FIGURE 4. Inflamm-aging as a consequence of macroph-aging. The increase in proinflammatory status at an organismal level, caused by chronic age-related stimulation of the macrophage,L’inflamm-aging called “macroph-aging,” is referred to as “inflamm-aging.” comme une conséquence du macroph-aging enon is only part of the whole spectrum of change characteristic of immunosenescence, and indeed the macrophage is not the only cell involved in the aging process. Lymphocytes are also largely affected during immunosenescence, and the continuous age-related, inescapable, antigenic stress provokes a variety of changes an evolutionary perspective largely on immunsenescence even in the most evolutionary recent, clonotypical immune system. The results were Les phénotypes de la vieillesse Table 2. Circulating mtDNA plasma levels in donors of different age, that is, from children to the oldest old. Group 1 log10 mtDNA (copies/mL) Group 2 log10 mtDNA (copies/mL) Group 3 log10 mtDNA (copies/mL) Group 4 (sib1—proband) log10 mtDNA (copies/mL) Group 5 (sib2) log10 mtDNA (copies/mL) Sex Males Females Mean (95% CI) 10.99 (10.88–11.09) 11.00 (10.88–11.11) Mean (95% CI) 10.79 (10.66–10.93) 10.90 (10.78–11.03) Mean (95% CI) 11.56a),b) (11.41–11.71) 11.36 a),b) (11.26–11.46) Mean (95% CI) 11.57a),b) (11.43–11.71) 11.74 a),b),c) (11.65–11.82) Mean (95% CI) 11.64a),b) (11.51–11.78) 11.67 a),b),c) (11.58–11.76) Total 10.99 (10.92–11.07) 10.84 (10.75–10.93) 11.42 a),b) (11.33–11.50) 11.69 a),b),c) (11.62–11.76) 11.66 a),b),c) (11.59–11.74) a) www.eji-journal.eu p < 0.001 versus group 1, ANOVA test with Bonferroni correction. Pinti et al_Circulating mitochondrial DNA increases with age and is a familiar trait: Implications for “inflamm-aging, 2014 b) p < 0.001 versus group 2, ANOVA test with Bonferroni correction. c) p < 0.001 versus group 3, ANOVA test with Bonferroni correction. Stade immature Stade mature Vieillissement Tregs Système immunitaire Th17 T Naïf T Mémoire TH1 TH2 Eur. J. Immunol. 2014. 44: 1552–1562 Groups Généralisation du vieillissement et du système immunitaire Œuf Maturité sexuelle Stade immature Mort Stade mature Vieillissement Vieillissement Inflammation Anti-inflammatoire Système immunitaire Pro-inflammatoire De la métamorphose... Qu’est-ce que la métamorphose ? Changement d’état (morphologique, physiologique et comportemental) brutal entre l’avant et l’après. 1262 ROBERT AND OHTA Robert-Ohta_Comparative and developmental study of the immune system in Xenopus, Fig. 3. Schematic overview summarizing the major developmental steps of the Xenopus immune system. For abbreviations, see list. Contrairement à la transformation, la métamorphose induit un changement morphologique brutal. 1262 ROBERT AND OHTA St 65 Fig. 3. Schematic overview summarizing the major developmental steps of the Xenopus immune system. For abbreviations, see list. (Hadji-Azimi et al., 1990). It is also 3.4. Differential Gene clear that, at the molecular level, the Expression of MHC and Ig repertoire in larvae and adults is Other Immune Genes different (Mussmann et al., 1998); this finding suggests that a new adult type MHC class I and class II genes are B cell population differentiates at differentially regulated during metasome developmental time point (Chen morphosis. MHC class I molecules are and Turpen, 1995). Tadpoles and first detected on erythrocytes and a adults of the same clone were used to minor splenocyte population at the beSt 66 the antibody response to ginning of metamorphosis (Flajnik et compare al., 1986; 2006 Flajnik and Du Pasquier, de Wallace Arthur_D'Arcy Thompson and the theory of transformations, DNP by isoelectric focusing. Results 1988; Rollins-Smith et al., 1997a). Af3.3. B Cells and showed that immunized larvae proter metamorphosis, however, class II 1980). Moreover, thymectomy performed at late premetamorphic developmental stage abrogates the ability to induce larval allotolerance of skin grafts (Barlow and Cohen, 1983). Although NK cells are detected from the beginning of metamorphosis with the mAb 1F8, significant NK killing activity in vitro can only be detected in adults of approximately 1 year of age. Inspiré La et le système immunitaire du xénope 1262métamorphose ROBERT AND OHTA Métamorphose Œuf Larve 50 Stade immature Système immunitaire Maturité sexuelle Stade mature Quels changements? Robert-Ohta_Comparative and developmental study of the immune system in Xenopus, 2009. Fig. 3. Schematic overview summarizing the major developmental steps of the Xenopus immune system. For abbreviations, see list. La métamorphose et le système immunitaire du xénope 1262 ROBERT AND OHTA Spécificité ? Réarrangements des gènes VDJ post 66 : • Expression de l’enzyme TDT • Expression des molécules de classe Ib • Tolérance des antigènes adultes et perte de tolérance des antigènes larvaires 50 : Rate devient lymphoïdes 47 : Thymus devient un organe lymphoïde Mémoire Fig. 3. Schematic overview summarizing the major developmental steps of the Xenopus immune system. For abbreviations, see list. 1980). Moreover, thymectomy performed at late premetamorphic devel- (Hadji-Azimi et al., 1990). It is also clear that, at the molecular level, the Robert-Ohta_Comparative and developmental study of the immune system in Xenopus, 2009. 3.4. Differential Gene Expression of MHC and L’entrée en métamorphose chez les amphibiens : le rôle des hormones permettant l’apoptose des lymphocytes Métamorphose Stade immature Œuf Larve 50 Stade mature Maturité sexuelle Corticoid binding in Xenopus (tadpoles and adults) T3 T4 (pas d’effets inhibiteurs de la proliferation) Table 2. Concentrationof total corticosterone, bound fraction and unbound fraction in the plasma of Corticosteroïdes (apoptose des lymphocytes) zone interrenale Thyroïde ACTH Glande pituitaire CRH Hypothalamus Xenopu~ heuis tadpoles and adults (at 4°C) Boundcorticosteronet Total corticosterone* ng.ml-’ c ng.ml-’ * , Unbound corticosteronet ng.ml-’ Lt La 4.6 + 1.47 (4) 4.2 0.3 Beginning of metamorphosis st 54 to 58 14.2 + 1.44 (11) 12.6 Beginning of climax st 59 to 61 21.3 + 1.80 (11) 17.45 - 3.6 Middle of climax st 62 to 63 45.8 + 3.96 (5) 22.5 - 23.1 End of climax st 64 and 65 17.1 +3.11 (41 14.8 - Adults TSH 347 0.1 1.5 2.25 Meansare givenwith their standarderrors,in brackets, number of determinations. Jolivet-Jaudet et Leloup, Corticosteroid in plasma of Xenopus laevis. *Concentrations evaluated in the present study (adults) biding or previously [13] (tadpoles) by radioimmunoassay chloride extracts. during metamorphosis and growth, 1985. Modifications tCalculatcd in according to [25] and [26]; Lt: corticosterone bound to the high affinity component; La: corticosterone bound to the low affinity component. dexamethasone or RU 28 362 were effective in inhibiting the binding of [3H]corticosterone to Xenopus plasma. That is quite unexpected, since in mammals, testosterone binding to CBG is not very strong whatever the considered species (4 to 100 times less strongly than corticosterone) [28] and synthetic on methylene determined until now whether high levels of this steroid exist in the plasma. In the plasma of tadpoles, only one binding component was characterized. No significant difference could be detected in the K. and in the electrophoretic mobility in tadpoles, juveniles and adults concerning L’entrée en métamorphose est hormono-dépendante. Pro-metamorphosis Metamorphosis 56/57 7 weeks 8 weeks 8 weeks 13 weeks 14 weeks 15 weeks 15 weeks 16 weeks 6 weeks 17 weeks 17 weeks 18 weeks 18 weeks 6 months 6 months 7 months 7 months 8 months 0 months 12 months 18 months 4 years 14/14 36/36 10,000I.P. 5,000 I.P. 5,000 I.P. 1.105 S.C. 5.105 S.C. 1.105 S.C. 1.105 I.P. 1.105 S.C. 1.105 I.P. 1.106 S.C. 1.106 I.P. 1.106 S.C. 1.106 I.P. 1.106 S.C. 5.106 S.C. 1.106 S.C. 2.5.106 S.C. 5.106 S.C. 2.106 S.C. 5.106 S.C. 5.106 S.C. 5.106 S.C. 100 100 100 100 80 92 71 60 L’entrée en métamorphose chez les amphibiens : le rôle des hormones permettant l’apoptose des lymphocytes 51/58 58/59 65/66 Post-metamorphosis Métamorphose Stade immature Œuf Larve 50 46 20120 12/12 415 11/12 517 6/10 1/5 3/10 014 1/10 015 014 118 015 014 015 016 20 Stade mature Maturité sexuelle 018 014 0110 Perte de 40 - 90% des lymphocytes dans le thymus, le foie et la rate 66 30 0 10 0 0 12.5 0 0 0 0 0 0 0 Metamorphosis o , ; ; . , - 107 -k z - 106 g e B -+- MLR ..f - 105 -V.Nb.thymocytesl f - 104 Système immunitaire Age 4w st 4 . 5 ~7 w 8w 13w 14w 15w 1 6 w 17w 18w 6 m 7m 8m IOm IZm 18m 4 y 50 s152 st 56 st 58 st66 TOLERANCE out exception, 15/0 tumor cell lines 'derived from LG15 g a Fig. 1. Resistance of ff host against transplantedff-2 during development increased in parallel with thymus histogenesis and mixed lymphocyte reaction (MLR) recovery. Percentage of animals (determined from the data of Table 1) that developed a tumor at the site of injection within 1 month is given (intraperitoneal and subcutaneous transplantation data from the same developmental stage were pooled). In brackets are the number of animals tested at each developmental stage. The MLR data are from [8] and the thymocyte number from [131 with 8 - 2 cells resisted tumor growth (Table 1) and were still alive 1 year later. The same results were obtained isogenic clones. This previously described observation Robert, Gui, Du Pasquier_ Ontogeny of the response a transplanted tumor in Xenopus laevis, 1995 with progeny of several $parents. Injection of more jf-2 [29]alloimmune was rechecked, andagainst no tumor growth was detected La métamorphose chez les ascidies 4742 B. Davidson and B. J. Swalla A B Dorsal Nerve Cord Notochord Endostyle Trunk Mesenchyme: Trunk Lateral Cells Mesenchyme Trunk Ventral Cells Endoderm Rudiment Cerebral Vesicle (ocellus) (otolith) Papillae C D H E F G I i ii iv iii Fig. 1. Ascidian metamorphosis (Cloney, 1990; Hirano and Nishida, 1997; Satoh, 1994). (A) Pre-competent ascidian larvae, showing the chordat dorsal nerve cord and notochord. The three cell lineages within the trunk mesenchyme form distinct mesodermal structures, as in B. (B) An adult ascidian showing the chordate endostyle and pharyngeal slits. The trunk lateral cells form structures (colored in red) including the blood cells, pa of the body wall musculature and the pharyngeal gill slit endothelia. The mesenchyme cells (colored green) migrate into the tunic. The trunk ventral cells form structures (colored in blue) including the heart and parts of the body wall musculature. (C-D) Upon detection of the appropriate settlement cue, competent larvae adhere to the substrate through adhesives secreted by the papillae. (E) The papillae retract, pulling the larval hea against the substrate. (F) Over the next 20 minutes the tail is resorbed. (G) Within an hour, the outer larval tunic is molted. (H,I) Close up diagram of the newly settled juvenile during the first few hours of metamorphosis. During this time (i) the cerebral vesicle is resorbed; (ii) the viscera rota 90 degrees; (iii) ampullae extend from the anterior epidermis, pushing the juvenile tunic along the substrate; and (iv) there is extensive migration trunk mesenchyme cells both within the body, across the epidermis into the tunic and through a tube to the exterior. La métamorphose de l’ascidie Davidson et J. Swalla_A molecular analysis of ascidian metamorphosis reveals activation of an innate immune response,2002 anterior papillary region (Fig. 5E, and see Fig. 6D). Although the migration of cells across the epidermis has been previously described, this had been characterized as occurring only after settlement (Cloney and Grimm, 1970). The initial migration of these cells into the tunic during the swimming larval period 4746 B. Davidson may and B.have J. Swalla implications for the acquisition of larval competence, as discussed below. Careful observation of settling larvae has led to the detection of a group of anterior most cells in the papillary region which migrate through a tunnel in the juvenile tunic to the external environment. Fig. 6 shows these cells at various stages during this migration. We have also conducted time-lapse movies clearly demonstrating this peculiar migration (Davidson et al., 2001). The position and morphology of these cells indicates that they are the same PAT cells identified by Eri et al. (Eri et al., 1999) as having a key role in metamorphic signaling. Eri et al. described these cells as being confined within a pocket of juvenile tunic but did not note any migration out of the tunic. DISCUSSION Expression de gènes de l’immunité innéeAn ascidian durant laresponse métamorphose immune during Fig. 6. Observations of PAT cell migrations (anterior is downward). (A) A competent larva viewed ventrally. Note extended papillae (pap), two layers of tunic (lt, larval tunic; jt, juvenile tunic), rounded blood cells (*) within the hemocoel (h). (B) 15 minutes after induction of settlement with 50 mM KCl filtered sea water. Note retraction of the papillae, an anterior cone of PAT cells has extended into the tunic space (black arrowhead), the anterior region has flattened and the tunic has begun to expand anteriorly. (C) 25 minutes after induction, note the anterior tunnel through the tunic and the PAT cell clearly migrating through the tunnel (black arrowhead). (D) 45 minutes after induction, the migrating PAT cell is now outside of the juvenile tunic. Under natural conditions the larval tunic is molted, leaving the migrating PAT completely exposed to the external environment. Also note the continued migration of rounded blood cells across the epidermis in the anterior (black arrowhead). metamorphosis Many of the genes that were isolated in our screens match remodeling is expressed resorbing those with gene described roles in in thethe innate immune system and cerebral vesicle, tail and muscle granules as two Selectins, vertebrate inflammatory responses, including well in the papillaryfactors, region Hemocytin, (Fig. 4D). InPentraxin, three threeasvon Willebrand juveniles, twofactors, days aafter settlement, complement trypsin-like serine Bvprotease, and two MASP expression is limited to faint staining of the body wall epidermis (Fig. 3P). The other four immune-related transcripts are expressed strongly in the epidermis of the ampullae as well as body wall epidermis. (Fig. 3Q-T). At higher magnification of these two-day juveniles, expression of Bv-Sccp2 (Fig. 4E) and Bv-Ccp3 (Fig. 4F) can be discerned in both the epidermis and in nearby blood cells. In contrast, expression of BvHspBP2 is not observed in the ampullae, and displays a distinctive pattern concentrated around the bases of the ampullae (Fig. 3W). Cell migrations across the epidermis during Boltenia metamorphosis Innate immune-related proteins may play a role in the adhesion and migration of blood cells that occur during B. villosa metamorphosis. We used propidium iodide staining to analyze the timing of cell migrations across the epidermis. As shown in Fig. 5, propidium iodide staining demonstrates that during the swimming larval stage, prior to metamorphosis, cells have already begun to migrate across the epidermis into the juvenile tunic. This early migration is Fig. 3. Expression patterns of isolated transcripts visualized through in situ hybridization. evident when comparing the 2-hour larvae, in Hybridation in situ de transcripts transcrits lors defourla métamorphose ascidie et tunic résorption Results for five immune-related and oneexprimés control transcript over the which there are d’une no cells in the juvenile developmental stages included in our screens are displayed. Transcripts are identified to (Fig. 5A), to the 15-hour larvae in which cells tissus larvaires the left of each row of images displaying their expression pattern over time. (A-E) Preare visible in a regularly spaced pattern competent larva, 1-2 hours after hatching. (F-U) Competent larvae, 10-12 hours after closely apposed to immune the epidermis et J.Swalla_A ascidian metamorphosis of an innate response,(Fig. 20025D). hatching. For allDavidson larval pictures we havemolecular chosen toanalysis displayofonly the head, because thisreveals activation Intriguingly, cells first migrate into the tunic allows the details of expression to be discerned and there was no significant expression in at 5-7 hours after hatching, corresponding to the tail region for any of the genes examined. (K-V) Juveniles 1 hour after settlement. des Articulation entre la métamorphose et le système immunitaire Métamorphose Œuf Larve 50 Stade immature Perte d’un répertoire Grande susceptibilité à l’apoptose et à la phagocytose Maturité sexuelle Stade mature Remodelage, réorganisation tissulaire Spécificité accrue de reconnaissance Système immunitaire TOLÉRANCE Création d’un nouveau répertoire Conclusion 1 • Plusieurs façons de voir le temps, • Les ruptures dans l’ontogénie induisent des changements hormono-dépendants dans le système immunitaire, • Après les ruptures, le système immunitaire acquiert un nouvel état, • Les balances du système immunitaire varient en fonction des ruptures (conclusion 2), • Les changements induits par la rupture ne sont pas pérennes (conclusion 2). Conclusion 2 État 1 Hormones Rupture État 2 Favorise l’état 2 Tolérance Pro-inflammatoire Rejet Anti-inflammatoire Merci au « See, Read » Salvador Dali, La persistance de la mémoire Video 10. Myeloid cells migrate preferentially towards the wound site after injury. 0.3 mm biopsy punch assay in the fin of a lurp:GFP transgenic Xenopus larva. The movie reflects 9 h of cell migration starting 15 min after injury located at the bottom of the movie. 5 confocal planes (Z-stack) were taken each 2 min, flattened down and projected as a continuous time-lapse. A video clip is available online. Supplementary material related to this article can be found online at http://dx.doi. org/10.1016/j.ydbio.2015.03.008. However, in the instance following a biopsy punch wound, a pvalue of 9.45e " 16 indicates a high confidence in the departure from uniformity (rejection of the null hypothesis), which in this particular case was in the direction of the wound located at 2701 (Fig. 5E and F). We confirmed that the average speed of migration was significantly higher after wounding (Fig. 5G). The preferred Fig. 6. Macrophage-like cells migrate preferentially towards the wound site after injury. (A) Schematic representation of a mpeg1:GFP transgenic Xenopus larva. (B) The speed of migration was calculated for each GFP þ cell following light stimulation (unwounded, green dots) or after biopsy punch wounding (wounded, red dots). The mean speed is indicated with a transversal black line. Mann–Whitney U-test, ***p o 0.001. (C) and (D) The magnitude and the angles of the displacement vectors obtained from the GFP þ cell tracks after light stimulation were plotted in rose charts (MatLab). (E) and (F) The magnitude and the angles of the displacement vectors obtained from the GFP þ cell tracks after biopsy punch wounding were plotted in rose charts (MatLab). The location of the wound site is denoted by a pink overshadow. Rayleigh test (CircStat for Parades et al_XenopusAnindicated. in vivo model for imaging the inflammatory response following injury and bacterial infection, 2015 MatLab, The MatWorks) p-values are also Les macrophages migrent préférentiellement vers le site de la blessure Please cite this article as: Paredes, R., et al., Xenopus: An in vivo model for imaging the inflammatory response following injury and bacterial infection. Dev. Biol. (2015), http://dx.doi.org/10.1016/j.ydbio.2015.03.008i La grossesse et la tolérance, les cellules T régulatrices sont attirées l’hCG 5494 Interface fœto-maternelle hCG Blastocyste Tregs Tregs Tregs FIGURE 8. Treg are not attracted by a non-hCG-producing cell line (HaCat). The keratinocyte cell line HaCat did not produce hCG (A). In Schumacher et al, Human chorionic gonadotropine attracts regulatory cells intro the fetal-maternal contrast, JEG-3 cells produceinterface significant higher levelspregnancy, of hCG 2009. (A). The during early human two-chamber transwell system was used to determine the migration of Treg La métamorphose chez les oursins La réponse immune lors de la métamorphose, vers une diminution de NOl’expression signaux de stress ? REPRESSES ECHINOIDdes METAMORPHOSIS 398 397 C. D. BISHOP AND B. P. 2. SNAP can suppress after the Larvae addition of FigureFigure 4. Inhibitors of HSP90 or sGCmetamorphosis induce metamorphosis. L-NAME. wells (10 larvae/well) were treated with Eight 0.1% DMSO (control), 5 !Mwere RD, incubated or 50 !M with ODQ.L-NAME. The After h, the frequencywas of metamorphosis approximately 0.5, then frequency of 4metamorphosis monitored afterreached 3, 24, and 48 h. Asterisks SNAP was added to of the wells. frequency of of metaindicate0.1a mM significant difference in four the frequency of The metamorphosis 7 and 24 h thereafter. The (P asterisk"indicates larvae morphosis treated withwas RDscored or ODQ compared to controls. 0.01; a RD24 significant between timea points in theincrease frequency of metamorPRD48 " 0.02; n difference ! 4). ODQ caused significant within 3 h phosis among larvae treated with L-NAME (P0-7h ! 0.02; P7-24h ! 0.0005; (PODQ3 " 0.0004; n ! 4), with no further significant increase. L’inhibition des NOs, de la guanyly cyclase etndes promeut laindicates métamorphose $ 4).HSP90 The asterisk in parentheses a significant difference in the frequency of metamorphosis between larvae treated with L-NAME and Bishop et Randhorst_NO/cGMP signaling and HSP90 activity represses metamorphosis in the sea urchin Lytechnius pictus, 2001 L-NAME % SNAP after 24 h (P24 ! 0.03). ge low thi nu sit ser me thr po sec im sta ap co ch ing sit ex reg Re ga the frequency of metamorphosis over the untreated controls, ser and it did (Fig. 4). We have not measured directly whether MFSW (Fig. 4). In another experiment, larvae were treated ce 137 Table 1. Variation in growth capacity of transplanted ff-2 tumor cells during development Developmental period Pro-metamorphosis Metamorphosis Developmental stage Age No. of cells and route of injection Tumor incidence 50-5 1 52 56/57 4 weeks 4.5 weeks 7 weeks 8 weeks 8 weeks 13 weeks 14 weeks 15 weeks 15 weeks 16 weeks 6 weeks 17 weeks 17 weeks 18 weeks 18 weeks 6 months 6 months 7 months 7 months 8 months 0 months 12 months 18 months 4 years 5,000 I.P. 100,500, 1,000 I.P. 10,000I.P. 5,000 I.P. 5,000 I.P. 1.105 S.C. 5.105 S.C. 1.105 S.C. 1.105 I.P. 1.105 S.C. 1.105 I.P. 1.106 S.C. 1.106 I.P. 1.106 S.C. 1.106 I.P. 1.106 S.C. 5.106 S.C. 1.106 S.C. 2.5.106 S.C. 5.106 S.C. 2.106 S.C. 5.106 S.C. 5.106 S.C. 5.106 S.C. 23/23 3x 10/3x10 14/14 36/36 51/58 58/59 65/66 Post-metamorphosis 20120 12/12 415 11/12 517 6/10 1/5 3/10 014 1/10 015 014 118 015 014 015 016 018 014 0110 % of animals developing tumor 100 100 100 100 100 100 80 92 71 60 20 30 0 10 0 0 12.5 0 0 0 0 0 0 0 Metamorphosis o , ; ; . , Fig. 1. Resistance of ff host - 107 against transplantedff-2 during Robert, Gui, Du Pasquier_-k Ontogeny of the alloimmune response against a transplanted tumor in Xenopus laevis, 1995 z - 106 g e development increased in parallel with thymus histogenesis
