Autophagy is an important cellular degradation pathway with a central role in metabolism as well as basic quality control, two processes inextricably linked to ageing. A decrease in autophagy is ...associated with increasing age, yet it is unknown if this is causal in the ageing process, and whether autophagy restoration can counteract these ageing effects. Here we demonstrate that systemic autophagy inhibition induces the premature acquisition of age-associated phenotypes and pathologies in mammals. Remarkably, autophagy restoration provides a near complete recovery of morbidity and a significant extension of lifespan; however, at the molecular level this rescue appears incomplete. Importantly autophagy-restored mice still succumb earlier due to an increase in spontaneous tumour formation. Thus, our data suggest that chronic autophagy inhibition confers an irreversible increase in cancer risk and uncovers a biphasic role of autophagy in cancer development being both tumour suppressive and oncogenic, sequentially.
Ancient organisms have a combined coagulation and immune system, and although links between inflammation and hemostasis exist in mammals, they are indirect and slower to act. Here we investigated ...direct links between mammalian immune and coagulation systems by examining cytokine proproteins for potential thrombin protease consensus sites. We found that interleukin (IL)-1α is directly activated by thrombin. Thrombin cleaved pro-IL-1α at a site perfectly conserved across disparate species, indicating functional importance. Surface pro-IL-1α on macrophages and activated platelets was cleaved and activated by thrombin, while tissue factor, a potent thrombin activator, colocalized with pro-IL-1α in the epidermis. Mice bearing a mutation in the IL-1α thrombin cleavage site (R114Q) exhibited defects in efficient wound healing and rapid thrombopoiesis after acute platelet loss. Thrombin-cleaved IL-1α was detected in humans during sepsis, pointing to the relevance of this pathway for normal physiology and the pathogenesis of inflammatory and thrombotic diseases.
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•Mammalian IL-1α contains a highly conserved thrombin consensus site•Thrombin cleavage leads to IL-1α activation and shedding from the cell surface•Thrombin activates IL-1α after epidermal wounding and after acute platelet loss•Thrombin-cleaved IL-1α is also detected in humans during sepsis
Burzynski et al. reveal that the coagulation protease thrombin directly cleaves pro-interleukin (IL)-1α, rapidly activating the downstream inflammatory cascade. This cleavage site in IL-1α is conserved throughout mammals, suggesting that this link between coagulation and inflammation may be relevant in multiple disease settings.
Interleukin‐1 alpha (IL‐1α) is a powerful cytokine that modulates immunity, and requires canonical cleavage by calpain for full activity. Mature IL‐1α is produced after inflammasome activation and ...during cell senescence, but the protease cleaving IL‐1α in these contexts is unknown. We show IL‐1α is activated by caspase‐5 or caspase‐11 cleavage at a conserved site. Caspase‐5 drives cleaved IL‐1α release after human macrophage inflammasome activation, while IL‐1α secretion from murine macrophages only requires caspase‐11, with IL‐1β release needing caspase‐11 and caspase‐1. Importantly, senescent human cells require caspase‐5 for the IL‐1α‐dependent senescence‐associated secretory phenotype (SASP) in vitro, while senescent mouse hepatocytes need caspase‐11 for the SASP‐driven immune surveillance of senescent cells in vivo. Together, we identify IL‐1α as a novel substrate of noncanonical inflammatory caspases and finally provide a mechanism for how IL‐1α is activated during senescence. Thus, targeting caspase‐5 may reduce inflammation and limit the deleterious effects of accumulated senescent cells during disease and Aging.
How the inflammatory cytokine IL‐1α is activated is not well defined. Wiggins et al show that the inflammatory human caspase‐5 and mouse caspase‐11 directly cleave and activate pro‐IL‐1α. Intracellular LPS (icLPS) activates caspase‐5/‐11 in macrophages, leading to release of cleaved IL‐1α. Importantly, caspase‐5/‐11‐cleaved pro‐IL‐1α drives the senescence‐associated secretory phenotype (SASP), leading to immune‐mediated clearance of senescent cells in vivo.
Interleukin‐1 alpha (IL‐1α) is a powerful cytokine that drives inflammation and modulates adaptive immunity. Due to these powerful effects, IL‐1α is controlled at multiple levels from transcription ...to cleavage and release from the cell. Genome‐wide association studies can identify loci that drive important diseases, although often the functional effect of the variant on phenotype remains unknown or small, with most risk variants in non‐coding regions. We find that the common variant rs17561 changes a conserved amino acid in the central region of IL‐1α linking the pro piece to the cytokine domain. Using a recall‐by‐genotype study and whole blood stimulation, we find that minor allele homozygotes release ~50% less IL‐1α than the major allele, with IL‐1β release equivalent. IL‐1α transcript level was identical between groups, implying a post‐transcriptional effect, whilst cleavage of recombinant pro‐IL‐1α by multiple proteases was also equivalent for both forms. Importantly, transfected macrophages also release less minor allele IL‐1α upon inflammasome activation, revealing that reduced secretion is directly caused by the missense amino acid substitution and more minor allele IL‐1α was retained within the cell. Thus, rs17561 represents a very common hypomorphic mutation in IL‐1α. We believe this novel data will be important for determining the potential contribution of IL‐1α to disease and/or physiological processes, for example, by Mendelian randomisation, and may aid patient stratification when considering anti‐IL‐1 therapies.
Interleukin‐1 alpha (IL‐1α) is a powerful cytokine that drives inflammation and modulates adaptive immunity. We investigated whether the common variant rs17561, which changes a conserved amino acid in the central region of IL‐1α, altered cleavage, activation and/or function. Using a recall‐by‐genotype study and whole blood stimulation, we find that minor allele homozygotes release ~50% less IL‐1α than the major allele, with IL‐1β release equivalent.
To describe the frequency and extent of delivery room resuscitation and evaluate the association of delivery room resuscitation with neonatal outcomes in moderately preterm (MPT) infants.
This was an ...observational cohort study of MPT infants delivered at 290/7 to 336/7 weeks' gestational age (GA) enrolled in the Neonatal Research Network MPT registry. Infants were categorized into 5 groups based on the highest level of delivery room intervention: routine care, oxygen and/or continuous positive airway pressure, bag and mask ventilation, endotracheal intubation, and cardiopulmonary resuscitation including chest compressions and/or epinephrine use. The association of antepartum and intrapartum risk factors and discharge outcomes with the intensity of resuscitation was evaluated.
Of 7014 included infants, 1684 (24.0%) received routine care and no additional resuscitation, 2279 (32.5%) received oxygen or continuous positive airway pressure, 1831 (26.1%) received bag and mask ventilation, 1034 (14.7%) underwent endotracheal intubation, and 186 (2.7%) received cardiopulmonary resuscitation. Among the antepartum and intrapartum factors, increasing GA, any exposure to antenatal steroids and prolonged rupture of membranes decreased the likelihood of receipt of all levels of resuscitation. Infants who were small for GA (SGA) had increased risk of delivery room resuscitation. Among the neonatal outcomes, respiratory support at 28 days, days to full oral feeds and length of stay were significantly associated with the intensity of delivery room resuscitation. Higher intensity of resuscitation was associated with increased risk of mortality.
The majority of MPT infants receive some level of delivery room resuscitation. Increased intensity of delivery room interventions was associated with prolonged respiratory and nutritional support, increased mortality, and a longer length of stay.
The objectives describe the frequency that inadequate oral feeding (IOF) is the reason why moderately preterm (MPT) infants remain hospitalized and its association with neonatal morbidities.
...Prospective study using the NICHD Neonatal Research Network MPT Registry. Multivariable logistic regression was used to describe associations between IOF and continued hospitalization at 36 weeks postmenstrual age (PMA).
A total of 6017 MPT infants from 18 centers were included. Three-thousand three-seventy-six (56%) remained hospitalized at 36 weeks PMA, of whom 1262 (37%) remained hospitalized due to IOF. IOF was associated with RDS (OR 2.02, 1.66-2.46), PDA (OR 1.86, 1.37-2.52), sepsis (OR 2.36, 95% 1.48-3.78), NEC (OR 16.14, 7.27-35.90), and BPD (OR 3.65, 2.56-5.21) compared to infants discharged and was associated with medical NEC (OR 2.06, 1.19-3.56) and BPD (OR 0.46, 0.34-0.61) compared to infants remaining hospitalized for an alternative reason.
IOF is the most common barrier to discharge in MPT infants, especially among those with neonatal morbidities.
To assess whether length of hospital stay is decreased among moderately preterm infants weaned from incubator to crib at a lower vs higher weight.
This trial was conducted in the Eunice Kennedy ...Shriver National Institute of Child Health and Human Development Neonatal Research Network. Infants with gestational ages 29-33 weeks, birthweight <1600 g, and in an incubator were randomly assigned to a weaning weight of 1600 or 1800 g. Within 60 to 100 g of weaning weight, the incubator temperature was decreased by 1.0°C to 1.5°C every 24 hours until 28.0°C. The infants were weaned to the crib following stable temperature at 36.5°C to 37.4°C for 8 to 12 hours. Clothing and bedcoverings were standardized. The primary outcome was length of hospital stay from birth to discharge; secondary outcomes included length of stay and growth velocity from weaning to discharge. Adverse events were monitored.
Of 1565 infants screened, 885 were eligible, and 366 enrolled—187 to the 1600-g and 179 to the 1800-g group. Maternal and neonatal characteristics did not differ among weight groups. Length of hospital stay was a median of 43 days in the lower and 41 days in the higher weight group (P = .12). Growth velocity from completion of weaning to discharge was higher in the lower weight group, 13.7 g/kg/day vs 12.8 g/kg/day (P = .005). Groups did not differ in adverse events.
Among moderately preterm neonates, weaning from incubator to crib at a lower weight did not decrease length of stay, but was safe and was accompanied by higher weight gain after weaning.
ClinicalTrials.gov: NCT02160002.
To describe the frequency and findings of cranial imaging in moderately preterm infants (born at 290/7-336/7 weeks of gestation) across centers, and to examine the association between abnormal ...imaging and clinical characteristics.
We used data from the Neonatal Research Network Moderately Preterm Registry, including the most severe early (≤28 days) and late (>28 days) cranial imaging. Stepwise logistic regression and CART analysis were performed after adjustment for gestational age, antenatal steroid use, and center.
Among 7021 infants, 4184 (60%) underwent cranial imaging. These infants had lower gestational ages and birth weights and higher rates of small for gestational age, outborn birth, cesarean delivery, neonatal resuscitation, and treatment with surfactant, compared with those without imaging (P < .0001). Imaging abnormalities noted in 15% of the infants included any intracranial hemorrhage (13.2%), grades 3-4 intracranial hemorrhage (1.7%), cystic periventricular leukomalacia (2.6%), and ventriculomegaly (6.6%). Histologic chorioamnionitis (OR, 1.47; 95% CI, 1.19-1.83), gestational age (0.95; 95% CI, 0.94-0.97), antenatal steroids (OR, 0.55; 95% CI, 0.41-0.74), and cesarean delivery (OR, 0.66; 95% CI, 0.53-0.81) were associated with abnormal imaging. The center with the highest rate of cranial imaging, compared with the lowest, had a higher risk of abnormal imaging (OR, 2.08; 95% CI, 1.10-3.92). On the classification and regression-tree model, cesarean delivery, center, antenatal steroids, and chorioamnionitis, in that order, predicted abnormal imaging.
Among the 60% of moderately preterm infants with cranial imaging, 15% had intracranial hemorrhage, cystic periventricular leukomalacia or late ventriculomegaly. Further correlation of imaging and long-term neurodevelopmental outcomes in moderately preterm infants is needed.
To identify approaches to target DNA repair vulnerabilities in cancer, we discovered nanomolar potent, selective, low molecular weight (MW), allosteric inhibitors of the polymerase function of DNA ...polymerase Polθ, including ART558. ART558 inhibits the major Polθ-mediated DNA repair process, Theta-Mediated End Joining, without targeting Non-Homologous End Joining. In addition, ART558 elicits DNA damage and synthetic lethality in BRCA1- or BRCA2-mutant tumour cells and enhances the effects of a PARP inhibitor. Genetic perturbation screening revealed that defects in the 53BP1/Shieldin complex, which cause PARP inhibitor resistance, result in in vitro and in vivo sensitivity to small molecule Polθ polymerase inhibitors. Mechanistically, ART558 increases biomarkers of single-stranded DNA and synthetic lethality in 53BP1-defective cells whilst the inhibition of DNA nucleases that promote end-resection reversed these effects, implicating these in the synthetic lethal mechanism-of-action. Taken together, these observations describe a drug class that elicits BRCA-gene synthetic lethality and PARP inhibitor synergy, as well as targeting a biomarker-defined mechanism of PARPi-resistance.
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