Are autistic children more vulnerable online? Relating autism to online safety, child wellbeing and parental risk management

Abstract Many autistic children are active online users. Research suggests that they are subject to distress and poor wellbeing following online safety threats. However, it is unclear if autistic children are more likely to experience online safety risks compared with non-autistic children. We conducted a parental online safety survey. Two groups of parents (autistic children, n=63; non-autistic children, n= 41) completed questionnaires about their child's online safety behaviours, wellbeing, and their own parental self-efficacy (PSE). Our results highlight that autistic children experience significantly more online safety risks than non-autistic children and poorer wellbeing than autistic children who did not experience online safety risks. Parents of autistic children reported carrying out significantly less risk management and reported poorer PSE than parents of non-autistic children. Having an autistic child and parental online safety knowledge were significant predictors of PSE. These results will help inform the co-design of interventions to protect autistic children online

HacA-Independent Functions of the ER Stress Sensor IreA Synergize with the Canonical UPR to Influence Virulence Traits in Aspergillus fumigatus

Endoplasmic reticulum (ER) stress is a condition in which the protein folding capacity of the ER becomes overwhelmed by an increased demand for secretion or by exposure to compounds that disrupt ER homeostasis. In yeast and other fungi, the accumulation of unfolded proteins is detected by the ER-transmembrane sensor IreA/Ire1, which responds by cleaving an intron from the downstream cytoplasmic mRNA HacA/Hac1, allowing for the translation of a transcription factor that coordinates a series of adaptive responses that are collectively known as the unfolded protein response (UPR). Here, we examined the contribution of IreA to growth and virulence in the human fungal pathogen Aspergillus fumigatus. Gene expression profiling revealed that A. fumigatus IreA signals predominantly through the canonical IreA-HacA pathway under conditions of severe ER stress. However, in the absence of ER stress IreA controls dual signaling circuits that are both HacA-dependent and HacA-independent. We found that a ΔireA mutant was avirulent in a mouse model of invasive aspergillosis, which contrasts the partial virulence of a ΔhacA mutant, suggesting that IreA contributes to pathogenesis independently of HacA. In support of this conclusion, we found that the ΔireA mutant had more severe defects in the expression of multiple virulence-related traits relative to ΔhacA, including reduced thermotolerance, decreased nutritional versatility, impaired growth under hypoxia, altered cell wall and membrane composition, and increased susceptibility to azole antifungals. In addition, full or partial virulence could be restored to the ΔireA mutant by complementation with either the induced form of the hacA mRNA, hacAi, or an ireA deletion mutant that was incapable of processing the hacA mRNA, ireAΔ10. Together, these findings demonstrate that IreA has both HacA-dependent and HacA-independent functions that contribute to the expression of traits that are essential for virulence in A. fumigatus

Deletion of <i>srgA</i> from <i>A. fumigatus</i>.

<p>Southern blot analysis of <i>Hind</i>III-digested genomic DNA using a probe located upstream of the <i>srgA</i> coding region (probe A) identified the predicted 2.8 kb fragment in wt <i>A. fumigatus</i>, which was lengthened to 10.3 kb in the Δ<i>srgA</i> mutant due to replacement of <i>srgA</i> with the phleomycin-resistance cassette (PHLEO).</p

Deletion of the <i>sec4</i> Homolog <i>srgA</i> from <i>Aspergillus fumigatus</i> Is Associated with an Impaired Stress Response, Attenuated Virulence and Phenotypic Heterogeneity

<div><p>Small GTPases of the Rab family are master regulators of membrane trafficking, responsible for coordinating the sorting, packaging and delivery of membrane-bound vesicles to specific sites within eukaryotic cells. The contribution of these proteins to the biology of the human pathogenic fungus <i>Aspergillus fumigatus</i> has not been explored. In this study, we characterized the <i>srgA</i> gene, encoding a Rab GTPase closely related to Sec4. We found that a GFP-SrgA fusion protein accumulated preferentially at hyphal tips and mature condiophores. The radial growth of a Δ<i>srgA</i> mutant was impaired on both rich and minimal medium, consistent with a role for SrgA in filamentous growth. In addition, the Δ<i>srgA</i> mutant revealed dysmorphic conidiophores that produced conidia with heterogeneous morphology. The Δ<i>srgA</i> mutant was hypersensitive to brefeldin A-mediated inhibition of vesicular trafficking and showed increased temperature sensitivity relative to wild type <i>A. fumigatus</i>. However, the most striking phenotype of this mutant was its phenotypic heterogeneity. Individual colonies isolated from the original Δ<i>srgA</i> mutant showed variable morphology with colony sectoring. In addition, each isolate of the Δ<i>srgA</i> mutant displayed divergent phenotypes with respect to thermotolerance, <i>in vitro</i> stress response and virulence in a <i>Galleria mellonella</i> infection model. Taken together, these results indicate that SrgA contributes to the asexual development and filamentous growth of <i>A. fumigatus</i>. However, the discordant phenotypes observed among individual isolates of the Δ<i>srgA</i> mutant suggest that the absence of <i>srgA</i> exerts selective pressure for the acquisition of compensatory changes, such as second-site suppressor mutations.</p></div

Sensitivity of Δ<i>srgA</i> to brefeldin A.

<p>Equal numbers of conidia were inoculated onto solid AMM media containing the indicated concentrations of brefeldin A (BFA) and incubated for three days at 37°C.</p

Strains used in this study.

<p>Strains used in this study.</p

Loss of SrgA impairs conidiation.

<p>A: All three Δ<i>srgA</i> isolates have attenuated conidophores and dysmorphic phialides (normal phialides are shown by the arrow in wt). B: All three Δ<i>srgA</i> isolates release conidia that are heterogeneous in both size and shape. Some of the elongated conidia may be abnormal phialides that are released along with the conidia (arrow) (Scale bar  = 20 µm).</p

Analysis of Δ<i>srgA</i> virulence in an insect model of <i>A. fumigatus</i> infection.

<p>Groups of 12 <i>G. mellonella</i> larvae were infected with conidia from the indicated strains. Larvae were incubated at 37°C and mortality was monitored over a five day period. Kaplan-Meier survival curves were compared using a log-rank test, followed by a pairwise multiple comparison test (Holm-Sidak). The Δ<i>srgA</i> isolate C survival curve is statistically different from wt, but isolates A and B were indistinguishable from wt.</p

Loss of SrgA impairs hyphal growth.

<p>Equal numbers of conidia were plated on the center of a plate of solid AMM and colony diameter was measured every day during a four-day incubation period at the indicated temperatures. The experiment was performed in triplicate and the values represent the mean ± SEM.</p

Relationship between <i>A. fumigatus</i> SrgA and Sec4 homologs.

<p>A: Comparison of G-box motifs (G1–G5) and C-termini (C) from fungal Sec4 homologs in <i>Saccharomyces cerevisiae (Sc)</i>, <i>Schizosaccharomyces pombe (Sp)</i>, <i>Candida albicans (Ca</i>), <i>Neurospora crassa (Nc)</i>), <i>Aspergillus niger (An)</i>, and <i>Aspergillus fumigatus (Af)</i>. B: Intracellular localization of <i>A. fumigatus</i> SrgA. The SrgA protein was tagged at its N-terminus with GFP and expressed in <i>A. fumigatus</i> under the control of the <i>gpdA</i> promoter. Scale bar  = 10 µm.</p