A genome-wide CRISPR/Cas9 screen to identify phagocytosis modulators in monocytic THP-1 cells.

Phagocytosis of microbial pathogens, dying or dead cells, and cell debris is essential to maintain tissue homeostasis. Impairment of these processes is associated with autoimmunity, developmental defects and toxic protein accumulation. However, the underlying molecular mechanisms of phagocytosis remain incompletely understood. Here, we performed a genome-wide CRISPR knockout screen to systematically identify regulators involved in phagocytosis of Staphylococcus (S.) aureus by human monocytic THP-1 cells. The screen identified 75 hits including known regulators of phagocytosis, e.g. members of the actin cytoskeleton regulation Arp2/3 and WAVE complexes, as well as genes previously not associated with phagocytosis. These novel genes are involved in translational control (EIF5A and DHPS) and the UDP glycosylation pathway (SLC35A2, SLC35A3, UGCG and UXS1) and were further validated by single gene knockout experiments. Whereas the knockout of EIF5A and DHPS impaired phagocytosis, knocking out SLC35A2, SLC35A3, UGCG and UXS1 resulted in increased phagocytosis. In addition to S. aureus phagocytosis, the above described genes also modulate phagocytosis of Escherichia coli and yeast-derived zymosan A. In summary, we identified both known and unknown genetic regulators of phagocytosis, the latter providing a valuable resource for future studies dissecting the underlying molecular and cellular mechanisms and their role in human disease.

Subsequent MRI of pediatric patients after an adverse reaction to Gadolinium-based contrast agents.

BACKGROUND: Gadolinium-based contrast agent (GBCA)-enhanced magnetic resonance imaging (MRI) scans often must be used repeatedly in pediatric oncologic patients. Although GBCAs are usually well tolerated, severe and life-threatening allergic reactions might occur, which can result in overly cautions adherence to special precautions in patients. PURPOSE: To evaluate the management of the reported GBCA-associated adverse reactions in subsequent contrast-enhanced MRIs in pediatric patients, distinguishing non-allergic and allergic reactions. MATERIALS AND METHODS: In this retrospective, cross-sectional study, consecutive pediatric neurooncological patients who underwent GBCA-enhanced MRI at our university hospital, between 2007 and 2016, were eligible. The patients' history was evaluated with regard to any adverse events after GBCA administration. In a subset of patients with reported adverse reactions, the institutional premedication regime or an allergy work-up in clinical practice were performed, using either skin-prick tests or intravenous provocation tests in a double-blind procedure. RESULTS: Included were 8156 contrast-enhanced MRI scans in 2109 patients. Nineteen acute adverse events (19/8156; 0.23%) in 17 patients (17/2109; 0.81%) were reported. Despite a premedication regime in 14 patients, three patients (3/14; 21.4%) reported a breakthrough reaction. None of the 12 patients who underwent skin-prick tests or intravenous provocation tests showed allergic reactions. At least one well-tolerated GBCA was identified in almost every tested patient. CONCLUSION: A fast-track allergy work-up can help to distinguish non-allergic and allergic reactions and to identify a well-tolerated GBCA, thus avoiding unnecessary premedication for subsequent GBCA administrations.

RESICARD: East Paris network for the management of heart failure: absence of effect on mortality and rehospitalization in patients with severe heart failure admitted following severe decompensation.

BACKGROUND: Heart failure presents a major public health problem due to its high prevalence and the increasing number of hospital admissions for this condition. A coordinated healthcare network involving general practitioners and cardiologists was set up in the east of Paris in an effort to improve the management and outcomes of patients with severe heart failure. AIMS: To reinforce patient education, improve compliance with medications and identify symptoms requiring treatment modification. METHODS: In this 'before and after' study, the control group comprised patients hospitalized for severe heart failure who received conventional management in the year preceding the network set-up. The comparative group consisted of patients hospitalized for severe heart failure who underwent network-led care. RESULTS: No significant differences were found between rates of first rehospitalization and all-cause mortality at 1 year between control and network groups, or between rates of first hospitalization due to cardiac causes, time to the first event, duration of hospitalization, rates of cardiac death or time to death. CONCLUSIONS: In this non-randomized study, we found no benefit from management according to the RESICARD healthcare network in terms of mortality or hospitalization in patients with severe chronic heart failure.