Circadian rhythms in thrombosis and atherothrombotic events.

Biological circadian rhythms in living organisms are regulated by molecular clocks. Several of these clocks are present in blood vessels, peripheral tissues, and immune cells. There is strong evidence linking dysregulation of circadian rhythms to the development of cardiovascular disease. Dysregulation of circadian rhythms is believed to activate inflammatory processes at specific times of day, leading to an increased risk of thrombosis and atherosclerosis progression. Research into circadian clock genes and molecular networks has the potential to identify therapeutic targets to reduce cardiovascular risk. In this review, we summarize the evidence linking circadian rhythms to thrombosis and atherothrombotic events and discuss potential therapeutic implications.This research received no external funding.S

Behavioral immune landscapes of inflammation.

Transcriptional or proteomic profiling of individual cells have revolutionized interpretation of biological phenomena by providing cellular landscapes of healthy and diseased tissues. These approaches, however, fail to describe dynamic scenarios in which cells can change their biochemical properties and downstream “behavioral” outputs every few seconds or minutes. Here, we used 4D live imaging to record tens to hundreds of morpho-kinetic parameters describing the dynamism of individual leukocytes at sites of active inflammation. By analyzing over 100,000 reconstructions of cell shapes and tracks over time, we obtained behavioral descriptors of individual cells and used these high-dimensional datasets to build behavioral landscapes. These landscapes recognized leukocyte identities in the inflamed skin and trachea, and inside blood vessels uncovered a continuum of neutrophil states, including a large, sessile state that was embraced by the underlying endothelium and associated with pathogenic inflammation. Behavioral in vivo screening of thousands of cells from 24 different mouse mutants identified the kinase Fgr as a driver of this pathogenic state, and genetic or pharmacological interference of Fgr protected from inflammatory injury. Thus, behavioral landscapes report unique biological properties of dynamic environments at high cellular, spatial and temporal resolution.pre-print4302 K

Neutrophils in Physiology and Pathology.

Infections, cardiovascular disease, and cancer are major causes of disease and death worldwide. Neutrophils are inescapably associated with each of these health concerns, by either protecting from, instigating, or aggravating their impact on the host. However, each of these disorders has a very different etiology, and understanding how neutrophils contribute to each of them requires understanding the intricacies of this immune cell type, including their immune and nonimmune contributions to physiology and pathology. Here, we review some of these intricacies, from basic concepts in neutrophil biology, such as their production and acquisition of functional diversity, to the variety of mechanisms by which they contribute to preventing or aggravating infections, cardiovascular events, and cancer. We also review poorly explored aspects of how neutrophils promote health by favoring tissue repair and discuss how discoveries about their basic biology inform the development of new therapeutic strategies.We thank all members of our laboratory and colleagues worldwide for discussion and contributions to the concepts summarized in this review. Work in our lab is supported by grants R01AI165661 from the National Institutes of Health and National Institute of Allergy and Infectious Disease, RTI2018-095497-B-I00 from the Ministerio de Ciencia e Innovacion (MCIN), HR17_00527 from Fundación La Caixa, and FET-OPEN 861878 from the European Commission. A.A-C. and T.V. are supported by fellowships from la Caixa Foundation (ID 100010434), with codes LCF/BQ/DR19/11740022 (A.A-C.) and LCF/BQ/DR21/11880022 (T.V.). The CNIC is supported by the MCIN and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (CEX2020-001041-S).S

In Vivo Imaging of Circadian NET Formation During Lung Injury by Four-Dimensional Intravital Microscopy

Neutrophil extracellular traps (NETs) are toxic extracellular structures deployed by neutrophils in response to pathogens and sterile danger signals. NETs are circadian in nature as mouse and human neutrophils preferentially deploy them at night or early morning. Traditionally, NETs have been quantified using a plethora of methods including immunofluorescence and ELISA-based assays; however few options are available to visualize them in vivo. Here we describe a method to directly visualize and quantify NET formation and release in the microvasculature of the lung using intravital imaging in a model of acute lung injury. The method allows four-dimensional capture and quantification of NET formation dynamics over time and should be a useful resource for those interested in visualizing neutrophil responses in vivo