Fumarate induces vesicular release of mtDNA to drive innate immunity.

Mutations in fumarate hydratase (FH) cause hereditary leiomyomatosis and renal cell carcinoma1. Loss of FH in the kidney elicits several oncogenic signalling cascades through the accumulation of the oncometabolite fumarate2. However, although the long-term consequences of FH loss have been described, the acute response has not so far been investigated. Here we generated an inducible mouse model to study the chronology of FH loss in the kidney. We show that loss of FH leads to early alterations of mitochondrial morphology and the release of mitochondrial DNA (mtDNA) into the cytosol, where it triggers the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING)-TANK-binding kinase 1 (TBK1) pathway and stimulates an inflammatory response that is also partially dependent on retinoic-acid-inducible gene I (RIG-I). Mechanistically, we show that this phenotype is mediated by fumarate and occurs selectively through mitochondrial-derived vesicles in a manner that depends on sorting nexin 9 (SNX9). These results reveal that increased levels of intracellular fumarate induce a remodelling of the mitochondrial network and the generation of mitochondrial-derived vesicles, which allows the release of mtDNAin the cytosol and subsequent activation of the innate immune response.

Human Factors Risk Analyses of a Doffing Protocol for Ebola-Level Personal Protective Equipment: Mapping Errors to Contamination.

Background: Doffing protocols for personal protective equipment (PPE) are critical for keeping healthcare workers (HCWs) safe during care of patients with Ebola virus disease. We assessed the relationship between errors and self-contamination during doffing. Methods: Eleven HCWs experienced with doffing Ebola-level PPE participated in simulations in which HCWs donned PPE marked with surrogate viruses (ɸ6 and MS2), completed a clinical task, and were assessed for contamination after doffing. Simulations were video recorded, and a failure modes and effects analysis and fault tree analyses were performed to identify errors during doffing, quantify their risk (risk index), and predict contamination data. Results: Fifty-one types of errors were identified, many having the potential to spread contamination. Hand hygiene and removing the powered air purifying respirator (PAPR) hood had the highest total risk indexes (111 and 70, respectively) and number of types of errors (9 and 13, respectively). ɸ6 was detected on 10% of scrubs and the fault tree predicted a 10.4% contamination rate, likely occurring when the PAPR hood inadvertently contacted scrubs during removal. MS2 was detected on 10% of hands, 20% of scrubs, and 70% of inner gloves and the predicted rates were 7.3%, 19.4%, 73.4%, respectively. Fault trees for MS2 and ɸ6 contamination suggested similar pathways. Conclusions: Ebola-level PPE can both protect and put HCWs at risk for self-contamination throughout the doffing process, even among experienced HCWs doffing with a trained observer. Human factors methodologies can identify error-prone steps, delineate the relationship between errors and self-contamination, and suggest remediation strategies.

Assessing Viral Transfer During Doffing of Ebola-Level Personal Protective Equipment in a Biocontainment Unit.

Background: Personal protective equipment (PPE) protects healthcare workers (HCWs) caring for patients with Ebola virus disease (EVD), and PPE doffing is a critical point for preventing viral self-contamination. We assessed contamination of skin, gloves, and scrubs after doffing Ebola-level PPE contaminated with surrogate viruses: bacteriophages MS2 and Φ6. Methods: In a medical biocontainment unit, HCWs (n = 10) experienced in EVD care donned and doffed PPE following unit protocols that incorporate trained observer guidance and alcohol-based hand rub (ABHR). A mixture of Φ6 (enveloped), MS2 (nonenveloped), and fluorescent marker was applied to 4 PPE sites, approximating body fluid viral load (Φ6, 105; MS2, 106). They performed a patient care task, then doffed. Inner gloves, face, hands, and scrubs were sampled for virus, as were environmental sites with visible fluorescent marker. Results: Among 10 HCWs there was no Φ6 transfer to inner gloves, hands, or face; 1 participant had Φ6 on scrubs at low levels (1.4 × 102). MS2 transfer (range, 101-106) was observed to scrubs (n = 2), hands (n = 1), and inner gloves (n = 7), where it was highest. Most (n = 8) had only 1 positive site. Environmental samples with visible fluorescent marker (n = 21) were negative. Conclusions: Among experienced HCWs, structured, observed doffing using ABHR protected against hand contamination with enveloped virus. Nonenveloped virus was infrequent on hands and scrubs but common on inner gloves, suggesting that inner gloves, but not necessarily ABHR, protect against hand contamination. Optimizing doffing protocols to protect against all types of viruses may require reinforcing careful handling of scrubs and good glove/hand hygiene with effective agents.

Reasons for indoor tanning use and the acceptability of alternatives: A qualitative study.

RATIONALE: Using indoor tanning devices is associated with substantial health consequences, such as an increased risk of melanoma and other skin cancers. Many people including minors and some at high risk of skin cancer continue to use these devices. In the absence of effective restrictions on use, it is important that behaviour change interventions are designed to reduce indoor tanning. OBJECTIVE: To explore reasons for use of indoor tanning devices and the acceptability of alternatives in adult users residing in North-West England. METHODS: Participants were required to be current indoor tanners aged 18 years and above and were recruited online. Twenty-one participants took part in either a focus group or semi-structured interview. An inductive thematic analysis was conducted. RESULTS: Six themes were identified: psychological benefits; improving physical health; denial of health risks; alternatives do not meet psychological needs; alternatives do not meet physical needs; and perceived side-effects. Participants used indoor tanning devices to improve their self-esteem and to prevent sun damage to their skin (by gaining a 'base tan'). Participants appeared to justify their usage by responding defensively to avoid accepting they were at risk, exaggerating the benefits of indoor tanning, and discounting alternatives to indoor tanning. Alternatives to indoor tanning were perceived as risky for health, inadequate to provide the desired aesthetic, and incapable of meeting their self-esteem needs. CONCLUSIONS: Interventions to reduce indoor tanning behaviour should increase sources of self-esteem other than appearance, increase media literacy and address defensive responses to information around indoor tanning and alternatives. Further research is needed to develop these interventions and assess their feasibility.

RalA and PLD1 promote lipid droplet growth in response to nutrient withdrawal.

Lipid droplets (LDs) are dynamic organelles that undergo dynamic changes in response to changing cellular conditions. During nutrient depletion, LD numbers increase to protect cells against toxic fatty acids generated through autophagy and provide fuel for beta-oxidation. However, the precise mechanisms through which these changes are regulated have remained unclear. Here, we show that the small GTPase RalA acts downstream of autophagy to directly facilitate LD growth during nutrient depletion. Mechanistically, RalA performs this function through phospholipase D1 (PLD1), an enzyme that converts phosphatidylcholine (PC) to phosphatidic acid (PA) and that is recruited to lysosomes during nutrient stress in a RalA-dependent fashion. RalA inhibition prevents recruitment of the LD-associated protein perilipin 3, which is required for LD growth. Our data support a model in which RalA recruits PLD1 to lysosomes during nutrient deprivation to promote the localized production of PA and the recruitment of perilipin 3 to expanding LDs.

Social Judgments of Digitally Manipulated Stuttered Speech: Cognitive Heuristics Drive Implicit and Explicit Bias.

Purpose People who stutter are susceptible to discrimination, stemming from negative stereotypes and social misattributions. There has been a recent push to evaluate the underlying explicit and implicit cognitive mechanisms associated with social judgments, moving away from only evaluating explicit social bias about people who stutter. The purpose of the current study was to evaluate how listeners change their implicit and explicit social (mis)attributions after hearing a people who stutter produce disfluent speech. Method The current project was an adaptation of the Byrd et al. (2017) study to evaluate listener implicit/explicit social judgments of stuttered speech across five categories (i.e., confidence, friendliness, intelligence, distractibility, and extroversion) before and after a stuttering self-disclosure. This was done by implementing a modified version of the Ferguson et al. (2019) computer mouse-tracking paradigm. Results Consistent with previous findings, participants made more explicit positive social judgments of confidence, friendliness, extroversion, and intelligence after a stuttering self-disclosure, but the distractedness category was resistant to change. Also consistent with previous findings, participants experienced a higher degree of cognitive competition (i.e., higher area under the curve) shortly after self-disclosure, which lessened over time. Conclusions Explicit and implicit biases exist, but self-disclosure significantly impacts the cognitive system of listeners. Specifically, self-disclosure may reduce explicit bias through experience and explicit belief updating, but when cognitive heuristics are strong, implicit bias may be slower to change.

Social Judgments of Digitally Manipulated Stuttered Speech: An Evaluation of Self-Disclosure on Cognition.

Purpose Persons who stutter (PWS) may be susceptible to discrimination because of negative judgments made by listeners. The current study sought to determine how the cognitive system's explicit (i.e., conscious) and implicit (i.e., nonconscious) biases about PWS are impacted by self-disclosure. Method A computer mouse-tracking paradigm was used to evaluate categorical social judgments about PWS. Computer mouse trajectories, which have been shown to reveal underlying cognitive pull or competition between opposing concepts, were used to measure implicit bias (i.e., nonconscious stereotypes). Participants were asked to explicitly categorize the speaker as either intelligent or unintelligent before and after listening to a speaker self-disclose. Mouse cursor trajectories during the explicit response categorization were used to evaluate implicit bias associated with the decision-making process. Results Results indicated that participants chose "intelligent" for a higher proportion of the trials in the disclosure condition compared to baseline, showing that listeners' explicit biases changed after listening to a self-disclosure that the speaker stutters. Results also indicated listeners exhibited a more negative implicit bias, based on computer mouse trajectories, when rating the PWS relative to the "persons who do not stutter" talker, but this negative implicit bias did seem to reduce over time after the disclosure was made. Conclusions These findings indicate that, even though explicit and implicit biases were evident when listeners heard stuttering, both explicit and implicit biases seemed to extinguish over time after a self-disclosure. Although the bias was not completely extinguished, these results provide promising evidence toward developing methods to reduce negative beliefs and reactions toward PWS. Supplemental Material http://osf.io/mwrp7/.

Fumarate hydratase loss promotes mitotic entry in the presence of DNA damage after ionising radiation.

An altered response to DNA damage is commonly associated with genomic instability, a hallmark of cancer. Fumarate hydratase (FH) was recently characterised as a DNA repair factor required in non-homologous end-joining (NHEJ) through the local production of fumarate. Inactivating germline mutations in FH cause hereditary leiomyomatosis and renal cell cancer (HLRCC), a cancer syndrome characterised by accumulation of fumarate. Recent data indicate that, in FH-deficient cells, fumarate suppresses homologous recombination DNA repair upon DNA double-strand breaks, compromising genome integrity. Here, we show that FH loss confers resistance to DNA damage caused by ionising radiation (IR), and promotes early mitotic entry after IR in a fumarate-specific manner, even in the presence of unrepaired damage, by suppressing checkpoint maintenance. We also showed that higher levels of DNA damage foci are detectable in untreated FH-deficient cells. Overall, these data indicate that FH loss and fumarate accumulation lead to a weakened G2 checkpoint that predisposes to endogenous DNA damage and confers resistance to IR.

The Threat-Strategy Interview.

Operators in dynamic work environments use strategies to manage threats in order to achieve task goals. We introduce a structured interview method, the Threat-Strategy Interview (TSI), and an accompanying qualitative analysis to induce operator-level threats, strategies, and the cues that give rise to them. The TSI can be used to elicit knowledge from operators who are on the front line of managing threats to provide an understanding of strategic thinking, which in turn can be applied toward a variety of problems.

Strategic threat management: an exploration of nursing strategies in the pediatric intensive care unit.

Part of the work of a critical care nurse is to manage the threats that arise that could impede efficient and effective job performance. Nurses manage threats by employing various strategies to keep performance high and workload manageable. We investigated strategic threat management by using the Threat-Strategy Interview. Threats frequently involved technology, staff, or organizational components. The threats were managed by a toolbox of multifaceted strategies, the most frequent of which involved staff-, treatment- (patient + technology), examination- (patient + clinician), and patient-oriented strategies. The profile of strategies for a particular threat often leveraged work facets similar to the work facet that characterized the threat. In such cases, the nurse's strategy was directed at eliminating the threat (not working around it). A description at both a domain invariant level - useful for understanding strategic threat management generally - and a description at an operational, specific level - useful for guiding interventions-- are presented. A structural description of the relationship among threats, strategies, and the cues that trigger them is presented in the form of an evidence accumulation framework of strategic threat management.

Mitochondrial control by DRP1 in brain tumor initiating cells.

Brain tumor initiating cells (BTICs) co-opt the neuronal high affinity glucose transporter, GLUT3, to withstand metabolic stress. We investigated another mechanism critical to brain metabolism, mitochondrial morphology, in BTICs. BTIC mitochondria were fragmented relative to non-BTIC tumor cell mitochondria, suggesting that BTICs increase mitochondrial fission. The essential mediator of mitochondrial fission, dynamin-related protein 1 (DRP1), showed activating phosphorylation in BTICs and inhibitory phosphorylation in non-BTIC tumor cells. Targeting DRP1 using RNA interference or pharmacologic inhibition induced BTIC apoptosis and inhibited tumor growth. Downstream, DRP1 activity regulated the essential metabolic stress sensor, AMP-activated protein kinase (AMPK), and targeting AMPK rescued the effects of DRP1 disruption. Cyclin-dependent kinase 5 (CDK5) phosphorylated DRP1 to increase its activity in BTICs, whereas Ca(2+)-calmodulin-dependent protein kinase 2 (CAMK2) inhibited DRP1 in non-BTIC tumor cells, suggesting that tumor cell differentiation induces a regulatory switch in mitochondrial morphology. DRP1 activation correlated with poor prognosis in glioblastoma, suggesting that mitochondrial dynamics may represent a therapeutic target for BTICs.