Prevalence and Risk Factors of Neurologic Manifestations in Hospitalized Children Diagnosed with Acute SARS-CoV-2 or MIS-C.

BACKGROUND: Our objective was to characterize the frequency, early impact, and risk factors for neurological manifestations in hospitalized children with acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or multisystem inflammatory syndrome in children (MIS-C). METHODS: Multicenter, cross-sectional study of neurological manifestations in children aged <18 years hospitalized with positive SARS-CoV-2 test or clinical diagnosis of a SARS-CoV-2-related condition between January 2020 and April 2021. Multivariable logistic regression to identify risk factors for neurological manifestations was performed. RESULTS: Of 1493 children, 1278 (86%) were diagnosed with acute SARS-CoV-2 and 215 (14%) with MIS-C. Overall, 44% of the cohort (40% acute SARS-CoV-2 and 66% MIS-C) had at least one neurological manifestation. The most common neurological findings in children with acute SARS-CoV-2 and MIS-C diagnosis were headache (16% and 47%) and acute encephalopathy (15% and 22%), both P < 0.05. Children with neurological manifestations were more likely to require intensive care unit (ICU) care (51% vs 22%), P < 0.001. In multivariable logistic regression, children with neurological manifestations were older (odds ratio [OR] 1.1 and 95% confidence interval [CI] 1.07 to 1.13) and more likely to have MIS-C versus acute SARS-CoV-2 (OR 2.16, 95% CI 1.45 to 3.24), pre-existing neurological and metabolic conditions (OR 3.48, 95% CI 2.37 to 5.15; and OR 1.65, 95% CI 1.04 to 2.66, respectively), and pharyngeal (OR 1.74, 95% CI 1.16 to 2.64) or abdominal pain (OR 1.43, 95% CI 1.03 to 2.00); all P < 0.05. CONCLUSIONS: In this multicenter study, 44% of children hospitalized with SARS-CoV-2-related conditions experienced neurological manifestations, which were associated with ICU admission and pre-existing neurological condition. Posthospital assessment for, and support of, functional impairment and neuroprotective strategies are vitally needed.

5-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3,7-dimethoxy-4H-chromen-4-one (MSF-2) suppresses fMLP-mediated respiratory burst in human neutrophils by inhibiting phosphatidylinositol 3-kinase activity.

Respiratory burst mediates crucial bactericidal mechanism in neutrophils. However, undesirable respiratory burst leads to pathological inflammation and tissue damage. This study investigates the effect and the underlying mechanism of 5-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3,7-dimethoxy-4H-chromen-4-one (MSF-2), a lignan extracted from the fruit of Melicope Semecarprifolia, on fMLP-induced respiratory burst in human neutrophils and suggests a possible therapeutic approach to ameliorate disease associated with neutrophil hyperactivation. MSF-2 inhibited fMLP-induced neutrophil superoxide anion production, cathepsin G release and migration in human neutrophils isolated from healthy volunteers, reflecting inhibition of phosphatidylinositol 3-kinase (PI3K) activation. Specifically, PI3K/AKT activation results in migration, degranulation and superoxide anion production in neutrophils. MSF-2 suppresses PI3K activation and phosphatidylinositol (3,4,5)-trisphosphate (PIP3) production, and consequently inhibits downstream activation of PDK1 and AKT. Further, PI3K also stimulates respiratory burst via PLC-dependent elevation of intracellular calcium. MSF-2 reduces fMLP-mediated PLCγ2 activation and intracellular calcium accumulation notably through extracellular calcium influx in a PI3K and PLC-dependent manner. However, MSF-2 is not a competitive or allosteric antagonist of fMLP. Additionally, in an in vivo study, MSF-2 prevents fMLP-induced neutrophil infiltration and inflammation in mice. In conclusion, MSF-2 opposes fMLP-mediated neutrophil activation and inflammation by inhibiting PI3K activation and subsequent activation of AKT and PLCγ2.

The hormone receptor GUCY2C suppresses intestinal tumor formation by inhibiting AKT signaling.

BACKGROUND & AIMS: GUCY2C is the intestinal receptor for the paracrine hormones guanylin and uroguanylin that converts guanosine-5'-triphosphate to cyclic guanosine monophosphate (cGMP). It functions as a tumor suppressor; its loss disrupts intestinal homeostasis and promotes tumorigenesis. We investigated the effects of GUCY2C loss on intestinal cell proliferation, metabolism, signaling, and tumorigenesis in mice. METHODS: Intestinal cell proliferation and metabolism were examined in Gucy2c(-/-) and colon cancer cells by microscopy, immunoblot, and functional analyses. Microarray analyses compared gene expression profiles of intestine cell from Gucy2c(-/-) and wild-type mice. v akt murine thymoma viral oncogene homolog (AKT) regulation and signaling were examined, and the role of AKT in GUCY2C-dependent tumorigenesis was defined in Gucy2c(-/-)Akt1(-/-) mice. RESULTS: The size and number of intestinal crypts increased in Gucy2c(-/-) mice; the associated epithelial cells showed accelerated proliferation, increased glycolysis, and reduced oxidative phosphorylation, which was reversed by oral administration of cGMP. Conversely, activating guanylyl cyclase C in human colon cancer cells delayed cell-cycle progression, decreased DNA synthesis and colony formation, reduced glycolysis, and increased mitochondrial adenosine triphosphate production. AKT signaling pathways were activated in intestines of Gucy2c(-/-) mice, associated with increased AKT phosphorylation. Disruption of AKT activity, pharmacologically or genetically, reduced DNA synthesis, proliferation, and glycolysis, and increased mitochondrial biogenesis. Intestinal tumorigenesis increased after administration of azoxymethane to Gucy2c(-/-) mice, compared with wild-type mice, but was eliminated in Gucy2c(-/-)Akt1(-/-) mice. CONCLUSIONS: GUCY2C is a tumor suppressor that controls proliferation and metabolism of intestinal epithelial cells by inactivating AKT signaling. This receptor and its ligands, which are paracrine hormones, might be novel candidates for anticolorectal cancer therapy.

GUCY2C opposes systemic genotoxic tumorigenesis by regulating AKT-dependent intestinal barrier integrity.

The barrier separating mucosal and systemic compartments comprises epithelial cells, annealed by tight junctions, limiting permeability. GUCY2C recently emerged as an intestinal tumor suppressor coordinating AKT1-dependent crypt-villus homeostasis. Here, the contribution of GUCY2C to barrier integrity opposing colitis and systemic tumorigenesis is defined. Mice deficient in GUCY2C (Gucy2c(-/-)) exhibited barrier hyperpermeability associated with reduced junctional proteins. Conversely, activation of GUCY2C in mice reduced barrier permeability associated with increased junctional proteins. Further, silencing GUCY2C exacerbated, while activation reduced, chemical barrier disruption and colitis. Moreover, eliminating GUCY2C amplified, while activation reduced, systemic oxidative DNA damage. This genotoxicity was associated with increased spontaneous and carcinogen-induced systemic tumorigenesis in Gucy2c(-/-) mice. GUCY2C regulated barrier integrity by repressing AKT1, associated with increased junction proteins occludin and claudin 4 in mice and Caco2 cells in vitro. Thus, GUCY2C defends the intestinal barrier, opposing colitis and systemic genotoxicity and tumorigenesis. The therapeutic potential of this observation is underscored by the emerging clinical development of oral GUCY2C ligands, which can be used for chemoprophylaxis in inflammatory bowel disease and cancer.