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International audience; Gestational choriocarcinoma (CC) is an aggressive cancer that develops upon the occurrence of abnormal pregnancies such as Hydatidiform moles (HMs) or upon non-molar pregnancies. CC cells often metastasize in multiple organs and can cause maternal death. Recent studies have established an association between recurrent HMs and mutations in the Nlrp7 gene. NLRP7 is a member of a new family of proteins that contributes to innate immune processes. Depending on its level of expression, NLRP7 can function in an inflammasome-dependent or independent pathway. To date, the role of NLRP7 in normal and in malignant human placentation remains to be elucidated. We have recently demonstrated that NLRP7 is overexpressed in CC trophoblast cells and may contribute to their acquisition of immune tolerance via the regulation of key immune tolerance-associated factors, namely HLA family, βCG and PD-L1. We have also demonstrated that NLRP7 increases trophoblast proliferation and decreases their differentiation, both in normal and tumor conditions. Actual findings suggest that NLRP7 expression may ensure a strong tolerance of the trophoblast by the maternal immune system during normal pregnancy and may directly affect the behavior and aggressiveness of malignant trophoblast cells. The proposed review summarizes recent advances in the understanding of the significance of NLRP7 overexpression in CC and discusses its multifaceted roles, including its function in an inflammasome-dependent or independent pathways.

In this study, radiolabeled recombinant rat interleukin-1β (r125I-IL-1β) was used to localize and characterize IL-1β binding in rat hypothalamus and pituitary gland by quantitative autoradiography. The ability of this ligand to bind to type I IL· 1 receptor was first tested on murine lymphoma cells (EL-4). In the rat-tissue sections, high densities of specific r125I-IL-1β binding sites were localized in the anterior as well as the posterior pituitary and in the choroid plexus. A fine labeling was observed in meninges and third ventricle walls while no binding was detected in the hypothalamic nuclei. Saturation experiments, in the anterior and posterior pituitary, revealed one specific binding site with an affinity constant (Kd) of 0.5 nM. Competition experiments were achieved using either rat IL-1β (rIL-1β) or human IL-1s (hIL-1α, hIL-1β and IL-1 receptor antagonist: hIL-1α). Affinity constants (Ki) were drastically different according to the ligand used, while Ki values were found similar in anterior and posterior pituitary. Competition with rIL-1β revealed one binding affinity (Ki of 0.1 nM range). In contrast, competition with hIL-1β revealed two binding affinities: a high (Ki: 0.1 pM range) and a low one (Ki: 1 nM range). Competition with hlL-1ra was obtained for high concentrations only (Ki: 10–100 nM range), whereas human IL-1α (hIL-1α) was unable to compete at 1-100 nM. Therefore, two types of IL·1 binding affinities have been identified in rat pituitary tissues: a very high affinity binding, detected with hIL-1β only and a lower affinity binding. Human IL-1β can therefore be a better ligand for rat receptors than the rat ligand itself while hIL·lα is not. This is suggestive for the existence of several IL-1 receptor subtypes and is in accordance with the biological activity of hIL-1β in the rat. Moreover, the high density of binding sites observed in both anterior and posterior pituitary indicates that pituitary tissues are direct targets for IL-1 stimulation. It is worth noting that IL-1 binding sites cannot be detected in the rat hypothalamus. This raises the question of the mechanism of the hypothalamic IL-1-mediated effects and suggests a role of the third ventricular walls in this mediation.

International audience; Distribution of [35S]-TBPS binding sites was studied in various structures of brain in mouse and guinea pig and in cortex of monkey and in hippocampus of postmortem human brain. As it is observed for rat brain, high densities of [35S]-TBPS binding sites were found in layer IV of cortex in the four species, and in thalamus of mouse and guinea pig. Intermediate densities of binding sites were observed in superficial and deep layers of cortex in those four species and in hippocampus of mouse, guinea pig, and human. In all brain structures studied, 5 alpha 3 alpha P and picrotoxin produced a dose-dependent inhibition of [35S]-TBPS binding. No significant interregion or interspecies differences could not be detected for IC50 values of 5 alpha 3 alpha P or picrotoxin to inhibit [35S]-TBPS from its binding sites. In all regions studied, IC50 values were close to 1.5 x 10(-6) M for 5 alpha 3 alpha P and 2.3 x 10(-7) M for picrotoxin.

Amyloidosis are diseases characterised by self-agregation of misfolded proteins in fibrillary forms, called amyloid fibrils. They are associated with many diseases, and their early diagnosis remains a clinical challenge. In this work, we show the targeting and the detection of amyloid fibrils, from in vitro to in vivo experiments in mice models, useful for early diagnostic of amyloidosis. For that purpose, we use multimodal nanoparticles, further functionalized with specific molecules against amyloid fibrils. This multimodality for imaging (fluorescence, MRI, PET) represent a breakthrough in modern medicine, to add structural and functional informations. After negative toxicity tests on various cell lines, these nanoparticles have been tested on three different amyloid fibrils, formed with amyloid β(1-42) peptide (Alzheimer’s disease), amylin (type II diabetes mellitus), or mutated Val30Met transthyretin (familial polyneuropathy). As it is shown by spectroscopy and surface plasmon resonance experiments, nanoparticles grafted with generic targeters (Pittsburgh compound B or a nanobody) target the three amyloid fibrils, with good affinity, whereas nanoparticles vectorised with peptides show specific targeting for amyloid β(1-42) or Val30Met mutated transthyretin, but with lower affinity. The targeting by nanoparticles have been confirmed ex vivo on pathological tissues with each amyloid burden, thanks to fluorescence microscopy. Generic nanoparticles have been injected in Alzheimer’s mice model, and the monitoring in vivo by IRM and post-mortem by optical microscopy supposed a targeting of amyloid β(1-42) aggregates in brain. Furthermore, we demonstrate the possibility to detect amyloid fibrils without labelling. Spectroscopic measurements show original, and specific optical properties of amyloid fibrils, around the UV-visible and the near infra-red regions. Interestingly, these properties are also observed on pathological tissues by ex vivo fluorescence microscopy, and in vivo ongoing analysis by photoacoustic imagery and real-time imaging seems to be very promising. By multimodality of non-toxic grafted nanoparticles or by intrinsic properties of amyloid fibrils suggesting completely non-invasive tests, these two strategies can be useful for early diagnostic of amyloidoses in humans., Les amyloïdoses sont des maladies caractérisées par l’agrégation structurée de protéines, sous forme de fibres amyloïdes. Le diagnostic précoce de ces maladies représente un enjeu important, pour la prise en charge de nombreuses pathologies associées. Dans ce travail, nous avons montré le ciblage et la détection de plusieurs fibres amyloïdes, de l’in vitro à l’in vivo. Pour cela, nous avons utilisé des nanoparticules multimodales pour l’imagerie médicale (TEP, IRM), greffées avec diverses molécules ciblant les fibres. Trois types de fibres amyloïdes ont été testées, formées à partir du peptide amyloïde β (maladie d’Alzheimer), d’amyline (diabète de type 2), et de la transthyrétine (polyneuropathie familiale). Comme montré par des techniques de spectroscopie et de résonance plasmonique de surface (fluorescence et Biacore), des nanoparticules génériques (dû au greffage du Pittsburgh compound B ou d’un nanocorps) ciblent avec une bonne affinité les trois types de fibres in vitro, tandis que des nanoparticules spécifiques (dû au greffage de peptides) ciblent avec une affinité moindre les fibres d’amyloïde β ou de transthyrétine. Le ciblage et la détection des dépôts amyloïdes par les nanoparticules ont été confirmés par microscopie à fluorescence, sur des tissus de souris présentant chacune des trois maladies. Le suivi par imageries in vivo (par IRM) et post-mortem (par microscopie optique), après injection de nanoparticules génériques chez la souris Alzheimer, supposent un ciblage des dépôts amyloïdes intracérébraux. Par ailleurs, nous avons détecté les fibres amyloïdes sans aucun marquage. Des études spectroscopiques in vitro ont permis de montrer des propriétés luminescentes intrinsèques des fibres amyloïdes, dans l’UV-visible et le proche infrarouge. Ces caractéristiques ont été observées sur des coupes de tissus de cerveau de souris Alzheimer par microscopie à fluorescence, et les études in vivo en cours semblent prometteuses (par imagerie photo-acoustique, et en temps résolu). Que cela soit par l’utilisation de nanoparticules fonctionnalisées multimodales, ou de propriétés intrinsèques des fibres amyloïdes suggérant une détection complètement non-invasive, ces deux stratégies innovantes semblent adaptées pour le diagnostic précoce des amyloïdoses chez l’Homme.