Biological Significance of GPCR Heteromerization in the Neuro-Endocrine System

Clustering of proteins in higher order complexes is a common theme in biology and profoundly influences protein function. The idea that seven-transmembrane spanning G protein-coupled receptors (GPCRs) might form dimers or higher order oligomeric complexes has been formulated more than 20 years ago. Since then, this phenomenon has been investigated with many different biochemical and biophysical techniques. The more recent notion of GPCR heteromerization describes the specific association of two different GPCRs. GPCR heteromerization may be of primary importance in neuroendocrinology, as this may explain at least some of the functional crosstalks described between different hormonal systems. Importantly, many GPCR heteromers have distinct functional properties compared to their corresponding homomers. Heteromer-specific pharmacological profiles might be exploited for drug design and open new therapeutic options. GPCR heteromerization has been first studied in heterologous expression systems. Today, increasing evidence for the existence of GPCR heteromers in endogenous systems is emerging providing crucial evidence for the physiological function of GPCR heteromerization

Bitopic ligands: all-in-one orthosteric and allosteric

Natural ligands of G-protein-coupled receptors interact with the orthosteric ligand binding site, as do most of the classical synthetic ligands. The discovery of ligands targeting different, allosteric binding sites considerably expanded the repertoire of G-protein-coupled receptor ligands. More recently, bitopic ligands have been described that target both orthosteric and allosteric sites at the same time

Precision medicine in cancer: Challenges and recommendations from an EU-funded cervical cancer biobanking study

Background:Cervical cancer (CC) remains a leading cause of gynaecological cancer-related mortality worldwide. CC pathogenesis is triggered when human papillomavirus (HPV) inserts into the genome, resulting in tumour suppressor gene inactivation and oncogene activation. Collecting tumour and blood samples is critical for identifying these genetic alterations.Methods:BIO-RAIDs is the first prospective molecular profiling clinical study to include a substantial biobanking effort that used uniform high-quality standards and control of samples. In this European Union (EU)-funded study, we identified the challenges that were impeding the effective implementation of such a systematic and comprehensive biobanking effort.Results:The challenges included a lack of uniform international legal and ethical standards, complexities in clinical and molecular data management, and difficulties in determining the best technical platforms and data analysis techniques. Some difficulties were encountered by all investigators, while others affected only certain institutions, regions, or countries.Conclusions:The results of the BIO-RAIDs programme highlight the need to facilitate and standardise regulatory procedures, and we feel that there is also a need for international working groups that make recommendations to regulatory bodies, governmental funding agencies, and academic institutions to achieve a proficient biobanking programme throughout EU countries. This represents the first step in precision medicine

Bioinformatics for precision medicine in oncology: principles and application to the SHIVA clinical trial

Precision medicine (PM) requires the delivery of individually adapted medical care based on the genetic characteristics of each patient and his/her tumor. The last decade witnessed the development of high-throughput technologies such as microarrays and next-generation sequencing which paved the way to PM in the field of oncology. While the cost of these technologies decreases, we are facing an exponential increase in the amount of data produced. Our ability to use this information in daily practice relies strongly on the availability of an efficient bioinformatics system that assists in the translation of knowledge from the bench towards molecular targeting and diagnosis. Clinical trials and routine diagnoses constitute different approaches, both requiring a strong bioinformatics environment capable of (i) warranting the integration and the traceability of data, (ii) ensuring the correct processing and analyses of genomic data, and (iii) applying well-defined and reproducible procedures for workflow management and decision-making. To address the issues, a seamless information system was developed at Institut Curie which facilitates the data integration and tracks in real-time the processing of individual samples. Moreover, computational pipelines were developed to identify reliably genomic alterations and mutations from the molecular profiles of each patient. After a rigorous quality control, a meaningful report is delivered to the clinicians and biologists for the therapeutic decision. The complete bioinformatics environment and the key points of its implementation are presented in the context of the SHIVA clinical trial, a multicentric randomized phase II trial comparing targeted therapy based on tumor molecular profiling versus conventional therapy in patients with refractory cancer. The numerous challenges faced in practice during the setting up and the conduct of this trial are discussed as an illustration of PM application

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

L'angiotensine II et ses récepteurs AT[indice inférieur 1] et AT[indice inférieur 2] dans les cellules endothéliales vasculaires aortiques humaines présence, distribution et modulation du calcium intracellulaire

L'Angiotensine II (Ang II), un octapeptide hypertensif, est le principal médiateur du système rénine-angiotensine et joue un rôle proéminent dans la régulation des systèmes cardiovasculaire et rénal. La majorité des actions biologiques classiques de l'Ang II sont attribuées au récepteur AT[indice inférieur 1] alors que le récepteur AT[indice inférieur 2] semble antagoniser les effets du récepteur AT[indice inférieur 1]. Plusieurs études ont porté sur le rôle de l'Ang II, via ses récepteurs AT[indice inférieur 1] et AT[indice inférieur 2], au niveau des CEs animales et les CEs de la veine ombilicale humaine qui ne constituent pas un modèle représentatif des CEs adultes humaines. D'où l'importance de notre projet de recherche dont le but est de vérifier si l'Ang II et ses récepteurs AT[indice inférieur 1] et AT[indice inférieur 2] sont présents au niveau des cellules endothéliales aortiques humaines et si l'activation de ces récepteurs par l'Ang II induit leur mobilisation et leur synthèse de novo. De plus, nous avons voulu vérifier si l'Ang II, via ses récepteurs AT[indice inférieur 1] et/ou AT[indice inférieur 2], module le niveau du calcium libre cytosolique et nucléaire responsable de la sécrétion de différents facteurs endothéliaux.--Résumé abrégé par UMI

Rôle de la protéine C-MIP dans la physiopathologie moléculaire du syndrome néphrotique à lésions glomérulaires minimes

Le syndrome néphrotique à lésions glomérulaires minimes (SNLGM) à rechutes est la forme la plus fréquente des néphropathies glomérulaires chez l enfant. Il est considéré comme une pathologie dysimmunitaire dans laquelle des perturbations lymphocytaires T entraîneraient la sécrétion d un facteur circulant dont l interaction avec les podocytes causerait une désorganisation de la barrière de filtration et une protéinurie massive. Malgré de nombreuses études moléculaires et des avancées scientifiques indiscutables sur les formes génétiques, la pathogénie du SNLGM à rechutes reste une énigme. Nous avons trouvé que c-mip (c-maf induced protein) est surexprimée dans les lymphocytes ainsi que dans les podocytes et les tubules distaux de malades en poussée du SNLGM. Nous avons montré que les souris transgéniques qui surexpriment c-mip dans les podocytes présentent une protéinurie massive et reproduisent des lésions histologiques comparables à celles des patients atteints de SNLGM. Nous avons montré, in vitro, que la protéine c-mip interagit avec Fyn, inhibe son activation et rompt la liaison de Fyn avec la néphrine. La signalisation podocytaire de la néphrine est ainsi rompue entraînant une désorganisation du cytosquelette et une proteinurie massive. D autre part, nous avons démontré que la surexpression de c-mip, in vitro dans les lymphocytes T, inhibe l activation des voies NF B et AP-1. La protéine c-mip immunoprécipite avec le complexe p50/p65/I Ba et empêche la dégradation de I Ba et par conséquent la libération du dimère NF B et sa translocation nucléaire. La protéine c-mip bloque la translocation nucléaire de phospho-ERK1/2 via le recrutement de la DAPK ce qui empêche le facteur de transcription AP-1 d activer ses gènes cibles. Nous avons démontré pour la première fois l implication d une même protéine au niveau de la signalisation des lymphocytes T et des podocytes, deux cellules clés touchées au cours du SNLGM. La protéine c-mip est dotée de fonctions répressives dont les conséquences fonctionnelles dans les lymphocytes T et les podocytes sont différentes et peuvent expliquer le phénotype bipolaire de la maladie.Minimal Change Nephrotic Syndrome (MCNS) with relapse is an acquired glomerular disease characterized by a heavy proteinuria without inflammatory lesions or cell infiltrations. The pathophysiology of this disease remains an enigma. We showed that c-mip (c-maf inducing protein) is up-regulated in both T cells and podocytes, during the active phase of MCNS. We generated c-mip transgenic mice using the nephrin promoter to restrict transgene expression to podocytes. c-mip transgenic mice developed morphological and biochemical alterations similar to MCNS disease. We showed that c-mip switches off the podocyte proximal signaling by preventing the interaction between Fyn and nephrin. We also showed that c-mip blocks NF B and AP-1 signaling in T cells. c-mip interacts with the p65/p50/I Ba complex and inhibits I Ba degradation resulting in p65/p50 cytosolic sequestration. c-mip blocks phospho-ERK1/2 nuclear translocation via DAPK recruitment. Cytosolic phospho-ERK1/2 fails to activate AP-1 and consequently the transcription of its target genes. We are the first to describe the implication of a single protein, c-mip, in the regulation of the signaling pathways of both podocytes and T cells. c-mip functions as a negative regulator, the impacts of which on podocytes and T cells are different and might explain the bipolarity of the disease.PARIS12-Bib. électronique (940280011) / SudocSudocFranceF

Pan-cancer integrative molecular portrait towards a new paradigm in precision medicine

International audienceThis original book provides readers with an overview of the latest developments in personalized medicine clinical trials in oncology. The topics covered range from the rationale behind this new generation of clinical trials and the latest statistical models for high-throughput molecular techniques, bioinformatics, high-throughput screening molecular techniques and the challenges entailed by implementing them in daily practice. It also covers the key role of pathology in the validation of molecular results and the complex assessment of predictive biomarkers. The different topics covered are supplemented by unique concrete examples based on the SHIVA trial. The authors are all members of the French Curie Institute, one of the world's foremost cancer research institutions.

Asymmetry of GPCR oligomers supports their functional relevance

International audienceG protein-coupled receptors (GPCRs) can exist as dimers or as larger oligomeric clusters that enable intercommu-nication between different receptor protomers within the same complex. This phenomenon is observed at three distinct levels: (i) at the level of ligand binding where the activation of one protomer can allosterically inhibit or facilitate ligand binding to the second protomer; (ii) at the level of ligand-induced conformational switches, which occur between transmembrane domains of the two protomers; and (iii) within GPCR-associated protein complexes, either directly at the level of GPCR-interacting proteins or at further downstream levels of the complex. Intercommunication at these different levels introduces asymmetry within GPCR dimers wherein each protomer fulfills its specific task. In this review, we discuss how the asymmetric behavior of GPCRs highlights the advantage of oligomeric receptor organization and supports the functional relevance of GPCR dimerization