S. aureus drives itch and scratch-induced skin damage through a V8 protease-PAR1 axis.

Itch is an unpleasant sensation that evokes a desire to scratch. The skin barrier is constantly exposed to microbes and their products. However, the role of microbes in itch generation is unknown. Here, we show that Staphylococcus aureus, a bacterial pathogen associated with itchy skin diseases, directly activates pruriceptor sensory neurons to drive itch. Epicutaneous S. aureus exposure causes robust itch and scratch-induced damage. By testing multiple isogenic bacterial mutants for virulence factors, we identify the S. aureus serine protease V8 as a critical mediator in evoking spontaneous itch and alloknesis. V8 cleaves proteinase-activated receptor 1 (PAR1) on mouse and human sensory neurons. Targeting PAR1 through genetic deficiency, small interfering RNA (siRNA) knockdown, or pharmacological blockade decreases itch and skin damage caused by V8 and S. aureus exposure. Thus, we identify a mechanism of action for a pruritogenic bacterial factor and demonstrate the potential of inhibiting V8-PAR1 signaling to treat itch.

Nociceptor neurons direct goblet cells via a CGRP-RAMP1 axis to drive mucus production and gut barrier protection.

Neuroepithelial crosstalk is critical for gut physiology. However, the mechanisms by which sensory neurons communicate with epithelial cells to mediate gut barrier protection at homeostasis and during inflammation are not well understood. Here, we find that Nav1.8+CGRP+ nociceptor neurons are juxtaposed with and signal to intestinal goblet cells to drive mucus secretion and gut protection. Nociceptor ablation led to decreased mucus thickness and dysbiosis, while chemogenetic nociceptor activation or capsaicin treatment induced mucus growth. Mouse and human goblet cells expressed Ramp1, receptor for the neuropeptide CGRP. Nociceptors signal via the CGRP-Ramp1 pathway to induce rapid goblet cell emptying and mucus secretion. Notably, commensal microbes activated nociceptors to control homeostatic CGRP release. In the absence of nociceptors or epithelial Ramp1, mice showed increased epithelial stress and susceptibility to colitis. Conversely, CGRP administration protected nociceptor-ablated mice against colitis. Our findings demonstrate a neuron-goblet cell axis that orchestrates gut mucosal barrier protection.

Bacteria hijack a meningeal neuroimmune axis to facilitate brain invasion.

The meninges are densely innervated by nociceptive sensory neurons that mediate pain and headache1,2. Bacterial meningitis causes life-threatening infections of the meninges and central nervous system, affecting more than 2.5 million people a year3-5. How pain and neuroimmune interactions impact meningeal antibacterial host defences are unclear. Here we show that Nav1.8+ nociceptors signal to immune cells in the meninges through the neuropeptide calcitonin gene-related peptide (CGRP) during infection. This neuroimmune axis inhibits host defences and exacerbates bacterial meningitis. Nociceptor neuron ablation reduced meningeal and brain invasion by two bacterial pathogens: Streptococcus pneumoniae and Streptococcus agalactiae. S. pneumoniae activated nociceptors through its pore-forming toxin pneumolysin to release CGRP from nerve terminals. CGRP acted through receptor activity modifying protein 1 (RAMP1) on meningeal macrophages to polarize their transcriptional responses, suppressing macrophage chemokine expression, neutrophil recruitment and dural antimicrobial defences. Macrophage-specific RAMP1 deficiency or pharmacological blockade of RAMP1 enhanced immune responses and bacterial clearance in the meninges and brain. Therefore, bacteria hijack CGRP-RAMP1 signalling in meningeal macrophages to facilitate brain invasion. Targeting this neuroimmune axis in the meninges can enhance host defences and potentially produce treatments for bacterial meningitis.

Basophils are important for development of allergic skin inflammation.

BACKGROUND: Atopic dermatitis skin lesions exhibit increased infiltration by basophils. Basophils produce IL-4, which plays an important role in the pathogenesis of atopic dermatitis. OBJECTIVE: We sought to determine the role of basophils in a mouse model of antigen-driven allergic skin inflammation. METHODS: Wild-type mice, mice with selective and inducible depletion of basophils, and mice expressing Il4-driven enhanced green fluorescent protein were subjected to epicutaneous sensitization with ovalbumin or saline. Sensitized skin was examined by histology for epidermal thickening. Cells were analyzed for surface markers and intracellular expression of enhanced green fluorescent protein by flow cytometry. Gene expression was evaluated by real-time reverse transcription-quantitative PCR. RESULTS: Basophils were important for epidermal hyperplasia, dermal infiltration by CD4+ T cells, mast cells, and eosinophils in ovalbumin-sensitized mouse skin and for the local and systemic TH2 response to epicutaneous sensitization. Moreover, basophils were the major source of IL-4 in epicutaneous-sensitized mouse skin and promote the ability of dendritic cells to drive TH2 polarization of naive T cells. CONCLUSION: Basophils play an important role in the development of allergic skin inflammation induced by cutaneous exposure to antigen in mice.

Simple changes to the reporting environment produce a large reduction in the frequency of interruptions to the reporting radiologist: an observational study.

BACKGROUND: Interruptions are a cause of discrepancy, errors, and potential safety incidents in radiology. The sources of radiological error are multifactorial and strategies to reduce error should include measures to reduce interruptions. PURPOSE: To evaluate the effect of simple changes in the reporting environment on the frequency of interruptions to the reporting radiologist of a hospital radiology department. MATERIAL AND METHODS: A prospective observational study was carried out. The number and type of potentially disruptive events (PDEs) to the radiologist reporting inpatient computed tomography (CT) scans were recorded during 20 separate 1-h observation periods during both pre- and post-intervention phases. The interventions were (i) relocation of the radiologist to a private, quiet room, and (ii) initial vetting of clinician enquiries via a separate duty radiologist. RESULTS: After the intervention there was an 82% reduction in the number of frank interruptions (PDEs that require the radiologist to abandon the reporting task) from a median 6 events per hour to 1 (95% confidence interval [CI] = 4-6; P < 0.00001). The overall number of PDEs was reduced by 56% from a median 11 events per hour to 5 (95% CI = 4.5-11: P < 0.00001). CONCLUSION: Relocation of inpatient CT reporting to a private, quiet room, coupled with vetting of clinician enquiries via the duty radiologist, resulted in a large reduction in the frequency of interruptions, a frequently cited avoidable source of radiological error.

Expanding the phenotypic and molecular spectrum of NFS1-related disorders that cause functional deficiencies in mitochondrial and cytosolic iron-sulfur cluster containing enzymes.

Iron-sulfur cluster proteins are involved in critical functions for gene expression regulation and mitochondrial bioenergetics including the oxidative phosphorylation system. The c.215G>A p.(Arg72Gln) variant in NFS1 has been previously reported to cause infantile mitochondrial complex II and III deficiency. We describe three additional unrelated patients with the same missense variant. Two infants with the same homozygous variant presented with hypotonia, weakness and lactic acidosis, and one patient with compound heterozygous p.(Arg72Gln) and p.(Arg412His) variants presented as a young adult with gastrointestinal symptoms and fatigue. Skeletal muscle biopsy from patients 1 and 3 showed abnormal mitochondrial morphology, and functional analyses demonstrated decreased activity in respiratory chain complex II and variably in complexes I and III. We found decreased mitochondrial and cytosolic aconitase activities but only mildly affected lipoylation of pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase enzymes. Our studies expand the phenotypic spectrum and provide further evidence for the pathogenicity and functional sequelae of NFS1-related disorders with disturbances in both mitochondrial and cytosolic iron-sulfur cluster containing enzymes.

Detection of brain somatic variation in epilepsy-associated developmental lesions.

OBJECTIVE: Epilepsy-associated developmental lesions, including malformations of cortical development and low-grade developmental tumors, represent a major cause of drug-resistant seizures requiring surgical intervention in children. Brain-restricted somatic mosaicism has been implicated in the genetic etiology of these lesions; however, many contributory genes remain unidentified. METHODS: We enrolled 50 children who were undergoing epilepsy surgery into a translational research study. Resected tissue was divided for clinical neuropathologic evaluation and genomic analysis. We performed exome and RNA sequencing to identify somatic variation and we confirmed our findings using high-depth targeted DNA sequencing. RESULTS: We uncovered candidate disease-causing somatic variation affecting 28 patients (56%), as well as candidate germline variants affecting 4 patients (8%). In agreement with previous studies, we identified somatic variation affecting solute carrier family 35 member A2 (SLC35A2) and mechanistic target of rapamycin kinase (MTOR) pathway genes in patients with focal cortical dysplasia. Somatic gains of chromosome 1q were detected in 30% (3 of 10) of patients with Type I focal cortical dysplasia (FCD)s. Somatic variation in mitogen-activated protein kinase (MAPK) pathway genes (i.e., fibroblast growth factor receptor 1 [FGFR1], FGFR2, B-raf proto-oncogene, serine/threonine kinase [BRAF], and KRAS proto-oncogene, GTPase [KRAS]) was associated with low-grade epilepsy-associated developmental tumors. RNA sequencing enabled the detection of somatic structural variation that would have otherwise been missed, and which accounted for more than one-half of epilepsy-associated tumor diagnoses. Sampling across multiple anatomic regions revealed that somatic variant allele fractions vary widely within epileptogenic tissue. Finally, we identified putative disease-causing variants in genes not yet associated with focal cortical dysplasia. SIGNIFICANCE: These results further elucidate the genetic basis of structural brain abnormalities leading to focal epilepsy in children and point to new candidate disease genes.

KRIT1-positive hyperkeratotic cutaneous capillary venous malformation.

Cerebral cavernous malformations (CCM) may present in sporadic or familial forms, with different cutaneous manifestations including deep blue nodules, capillary malformations, and hyperkeratotic cutaneous capillary venous malformations (HCCVM). We report the case of an infant with a KRIT1-positive HCCVM associated with familial CCM. Moreover, histopathology showed positive immunohistochemical stain with GLUT1, further expanding the differential diagnosis of GLUT1-positive vascular anomalies.

Brain 3T magnetic resonance imaging in neonates: features and incidental findings from a research cohort enriched for preterm birth.

BACKGROUND AND OBJECTIVES: The survival rate and patterns of brain injury after very preterm birth are evolving with changes in clinical practices. Additionally, incidental findings can present legal, ethical and practical considerations. Here, we report MRI features and incidental findings from a large, contemporary research cohort of very preterm infants and term controls. METHODS: 288 infants had 3T MRI at term-equivalent age: 187 infants born <32 weeks without major parenchymal lesions, and 101 term-born controls. T1-weighted, T2-weighted and susceptibility-weighted imaging were used to classify white and grey matter injury according to a structured system, and incidental findings described. RESULTS: Preterm infants: 34 (18%) had white matter injury and 4 (2%) had grey matter injury. 51 (27%) infants had evidence of intracranial haemorrhage and 34 (18%) had punctate white matter lesions (PWMLs). Incidental findings were detected in 12 (6%) preterm infants. Term infants: no term infants had white or grey matter injury. Incidental findings were detected in 35 (35%); these included intracranial haemorrhage in 22 (22%), periventricular pseudocysts in 5 (5%) and PWMLs in 4 (4%) infants. From the whole cohort, 10 (3%) infants required referral to specialist services. CONCLUSIONS: One-fifth of very preterm infants without major parenchymal lesions have white or grey matter abnormalities at term-equivalent age. Incidental findings are seen in 6% of preterm and 35% of term infants. Overall, 3% of infants undergoing MRI for research require follow-up due to incidental findings. These data should help inform consent procedures for research and assist service planning for centres using 3T neonatal brain MRI for clinical purposes.

Novel Presentation of Hemiplegic Migraine in a Patient With Cockayne Syndrome.

BACKGROUND: Cockayne syndrome is a rare DNA repair disorder marked by premature aging, poor growth, and intellectual disability. Neurological complications such as seizures, movement disorder, and stroke have been reported. Hemiplegic migraine has not been reported in association with Cockayne syndrome. METHODS: We report a male with Cockayne syndrome due to biallelic heterozygous pathogenic variants in ERCC6 who presented repeatedly with transient focal neurological deficits and headache, which were consistent with hemiplegic migraine. Two siblings also had Cockayne syndrome and presented with similar symptoms. RESULTS: Our patient was originally diagnosed based on clinical suspicion and then confirmed by targeted exome analysis of genes associated with Cockayne syndrome. The family's research exome sequencing data were reanalyzed to identify variants in genes known to cause familial hemiplegic migraine. No variants in the genes known to cause familial hemiplegic migraine were identified. CONCLUSION: This is a novel association of familial hemiplegic migraine in three full siblings with Cockayne syndrome. Hemiplegic migraine has not previously been described as part of the Cockayne syndrome presentation. A separate genetic cause of familial hemiplegic migraines was not identified in an exome-based analysis of genes known to cause this condition. This report may represent an expansion of the Cockayne syndrome phenotype.

Expanding the clinical phenotype of FGFR1 internal tandem duplication.

Closed spinal dysraphism (SD) is a type of neural tube defect originating during early embryonic development whereby the neural tissue of the spinal defect remains covered by skin, often coinciding with markers of cutaneous stigmata. It is hypothesized that these events are caused by multifactorial processes, including genetic and environmental causes. We present an infant with a unique congenital midline lesion associated with a closed SD. Through comprehensive molecular profiling of the intraspinal lesion and contiguous skin lesion, an internal tandem duplication (ITD) of the kinase domain of the fibroblast growth factor receptor 1 (FGFR1) gene was found. This ITD variant is somatic mosaic in nature as supported by a diminished variant allele frequency in the lesional tissue and by its absence in peripheral blood. FGFR1 ITD results in constitutive activation of the receptor tyrosine kinase to promote cell growth, differentiation, and survival through RAS/MAPK signaling. Identification of FGFR1 ITD outside of central nervous system tumors is exceedingly rare, and this report broadens the phenotypic spectrum of somatic mosaic FGFR1-related disease.

Maternal mosaicism for a missense variant in the SMS gene that causes Snyder-Robinson syndrome.

There is increasing recognition for the contribution of genetic mosaicism to human disease, particularly as high-throughput sequencing has enabled detection of sequence variants at very low allele frequencies. Here, we describe an infant male who presented at 9 mo of age with hypotonia, dysmorphic features, congenital heart disease, hyperinsulinemic hypoglycemia, hypothyroidism, and bilateral sensorineural hearing loss. Whole-genome sequencing of the proband and the parents uncovered an apparent de novo mutation in the X-linked SMS gene. SMS encodes spermine synthase, which catalyzes the production of spermine from spermidine. Inactivation of the SMS gene disrupts the spermidine/spermine ratio, resulting in Snyder-Robinson syndrome. The variant in our patient is absent from the gnomAD and ExAC databases and causes a missense change (p.Arg130Cys) predicted to be damaging by most in silico tools. Although Sanger sequencing confirmed the de novo status in our proband, polymerase chain reaction (PCR) and deep targeted resequencing to ∼84,000×-175,000× depth revealed that the variant is present in blood from the unaffected mother at ∼3% variant allele frequency. Our findings thus provided a long-sought diagnosis for the family while highlighting the role of parental mosaicism in severe genetic disorders.

Math anxiety, but not induced stress, is associated with objective numeracy.

Many daily activities require a basic understanding of math. Numeracy, which refers to individual differences in the ability to understand numerical concepts and work with probabilities, has been linked to health-related decision-making and medical and financial outcomes. Whether affective influences impact numeracy has not been experimentally assessed, although research has shown that emotions impact judgments and decision-making. Stress is one commonly experienced affective influence that could impact numeracy. We examined whether objective and subjective numeracy were influenced by stress induced from anticipating giving a speech in a laboratory setting. We also examined the association of self-reported math anxiety, or apprehension pertaining to mathematics, with objective and subjective numeracy. Two experiments were conducted; the second was a direct replication. Undergraduate students (Experiment 1, n = 99; Experiment 2, n = 139) were randomly assigned to one of two conditions: a stress induction or a neutral condition. Whereas neither objective nor subjective numeracy significantly differed across conditions, math anxiety was a consistent predictor of objective and subjective numeracy. Math anxiety and baseline perceived stress did not consistently moderate any effects. These findings have implications for health care, educational, and financial contexts in which people must make decisions that involve complex numbers. (PsycInfo Database Record (c) 2020 APA, all rights reserved).