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Guillot, E. G.

Publications and source records attributed to Guillot, E. G..

3 recordsLinked to original sources

CRY-NLRP3 complexes define a circadian checkpoint controlling inflammasome activation

Innate immune sensors such as the NLRP3 inflammasome can trigger inflammatory responses within minutes, raising the question of how circadian clocks influence such rapid decisions. Here, we identify a protein-level circadian checkpoint that links core clock components to NLRP3 inflammasome activation. We show that NLRP3 associates with the circadian repressors CRY1 and CRY2, forming oscillatory complexes that restrain inflammasome activation and rapidly dissociate upon stimulation. Pharmacological stabilization of CRY proteins preserves CRY-NLRP3 association and attenuates inflammasome assembly, IL-1{beta} secretion and pyroptotic cell death in primary human macrophages. In synchronized macrophages, both NLRP3 inflammasome activation and its inhibition by the NLRP3 inhibitor MCC950 vary with circadian time. Finally, a subset of NLRP3 variants reported in cohorts of patients with Cryopyrin-Associated Periodic Syndromes (CAPS), a group of hereditary fever syndromes caused by mutations in NLRP3, weaken CRY binding and are associated with altered time-of-day patterns of inflammasome activation and MCC950 responsiveness. Together, these findings define CRY-NLRP3 complexes as a circadian checkpoint that modulates inflammasome activity and drug response, revealing time of day as a critical dimension of NLRP3-driven inflammation.

immunology↗

Inference and validation of a dynamic gene regulatory network influencing cell fate during Duchenne muscular dystrophy initiation

The onset of gene regulatory disturbances leading to developmental disorders remains poorly understood, particularly when symptoms begin after birth. Using induced pluripotent stem cells, single-cell transcriptomics and computational modeling, we determined the gene expression waves guiding early myogenesis and how they are affected by a disease-causing mutation. We uncovered a dynamic gene regulatory network organized in two kernels that function as a toggle-switch controlling stochastic cell fate decisions. In cells derived from patients with Duchenne muscular dystrophy, these waves of regulation are less pronounced and the switch remains in the OFF state with a higher probability, resulting in convergence into a restricted cell fate. Experimental reactivation of the switch through RNA interference led to a rescued transcriptomic state and to a refined network topology. This work uncovers a dynamic regulatory mechanism underlying early cell fate divergence and provides a general framework to infer and validate dynamic gene regulatory networks involved in disease initiation.

bioinformatics↗

Forecasting crowd dynamics through coarse-grained data analysis

Understanding and predicting the collective behaviour of crowds is essential to improve the efficiency of pedestrian flows in urban areas and minimize the risks of accidents at mass events. We advocate for the development of a & \"crowd forecasting system\"whereby real-time observations of crowds are coupled to fast and reliable models to produce rapid predictions of the crowd movement and eventually help crowd managers choose between tailored optimization strategies. Here, we propose a Bi-directional Macroscopic (BM) model as the core of such a system. Its key input is the fundamental diagram for bi-directional flows, i.e. the relation between the pedestrian fluxes and densities. We design and run a laboratory experiments involving a total of 119 participants walking in opposite directions in a circular corridor and show that the model is able to accurately capture the experimental data in a typical crowd forecasting situation. Finally, we propose a simple segregation strategy for enhancing the traffic efficiency, and use the BM model to determine the conditions under which this strategy would be beneficial. The BM model, therefore, could serve as a building block to develop on the fly prediction of crowd movements and help deploying real-time crowd optimization strategies.

animal behavior and cognition↗