In-flight sleep as a pilot fatigue mitigation on long range and ultra-long range flights : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Sleep/Wake Research Centre, Wellington, New Zealand

Objectives: Long range flights operate around the clock with long duty periods for pilots. To mitigate the effects of fatigue, these flights are operated by augmented crews, providing each pilot with the opportunity for sleep in on-board rest facilities. This thesis used a mixed methods approach to investigate the use of in-flight sleep and the factors that influence it. Methods: Retrospective survey data (291 pilots, five studies) were analysed to provide an overview of pilots’ sleep at home and investigate potential relationships with in-flight sleep. A second project monitored the sleep, fatigue and performance of 35 pilots operating a B767 flight route between Atlanta and Lagos. These projects were supplemented by thematic analysis of pilots’ logbook comments on in-flight sleep (N=123) and on the way they manage their fatigue (N=629). Results: Pilots viewed in-flight sleep as an important fatigue management strategy and actigraphic sleep monitoring confirmed that the B767 pilots made good use of their in-flight breaks for obtaining sleep. Self-ratings of in-flight sleep quality reflected ratings at home, but were usually poorer. Pilots indicated that the type, location and design of rest facilities affected sleep quality and duration, and identified strategies for minimizing sleep disturbances and improving alertness. Comments indicated that prior knowledge of inflight break allocations can influence the planning of pre-trip sleep, use of naps, and in-flight sleep. Actigraphic measures of sleep indicated that the B767 pilots obtained more sleep in the 24 hours prior to departure than during baseline days regardless of their subsequent pattern of in-flight breaks, but it is unclear when they were advised about their break pattern. Ratings of sleepiness and fatigue increased across the B767 flights, but psychomotor vigilance task performance at the start of duty and at top of descent was not associated with prior wakefulness, prior sleep duration or in-flight sleep duration. Conclusions: In-flight sleep is a well-utilized and effective fatigue mitigation strategy that may be supplemented by other strategies such as flight preparation techniques. To further reduce pilot fatigue risk on long range flights, additional research is warranted into the effects of flight preparation techniques and in-flight break patterns

Resident alveolar macrophageâ derived vesicular SOCS3 dampens allergic airway inflammation

Resident alveolar macrophages (AMs) suppress allergic inflammation in murine asthma models. Previously we reported that resident AMs can blunt inflammatory signaling in alveolar epithelial cells (ECs) by transcellular delivery of suppressor of cytokine signaling 3 (SOCS3) within extracellular vesicles (EVs). Here we examined the role of vesicular SOCS3 secretion as a mechanism by which AMs restrain allergic inflammatory responses in airway ECs. Bronchoalveolar lavage fluid (BALF) levels of SOCS3 were reduced in asthmatics and in allergenâ challenged mice. Ex vivo SOCS3 secretion was reduced in AMs from challenged mice and this defect was mimicked by exposing normal AMs to cytokines associated with allergic inflammation. Both AMâ derived EVs and synthetic SOCS3 liposomes inhibited the activation of STAT3 and STAT6 as well as cytokine gene expression in ECs challenged with ILâ 4/ILâ 13 and house dust mite (HDM) extract. This suppressive effect of EVs was lost when they were obtained from AMs exposed to allergic inflammationâ associated cytokines. Finally, inflammatory cell recruitment and cytokine generation in the lungs of OVAâ challenged mice were attenuated by intrapulmonary pretreatment with SOCS3 liposomes. Overall, AM secretion of SOCS3 within EVs serves as a brake on airway EC responses during allergic inflammation, but is impaired in asthma. Synthetic liposomes encapsulating SOCS3 can rescue this defect and may serve as a framework for novel therapeutic approaches targeting airway inflammation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154378/1/fsb220322-sup-0001-FigS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154378/2/fsb220322.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154378/3/fsb220322_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154378/4/fsb220322-sup-0005-TableS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154378/5/fsb220322-sup-0003-FigS3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154378/6/fsb220322-sup-0004-FigS4.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154378/7/fsb220322-sup-0002-FigS2.pd

An unexpected link between fatty acid synthase and cholesterol synthesis in proinflammatory macrophage activation

Different immune activation states require distinct metabolic features and activities in immune cells. For instance, inhibition of fatty acid synthase (FASN), which catalyzes the synthesis of long-chain fatty acids, prevents the proinflammatory response in macrophages; however, the precise role of this enzyme in this response remains poorly defined. Consistent with previous studies, we found here that FASN is essential for lipopolysaccharide-induced, Toll-like receptor (TLR)-mediated macrophage activation. Interestingly, only agents that block FASN upstream of acetoacetyl-CoA synthesis, including the well-characterized FASN inhibitor C75, inhibited TLR4 signaling, while those acting downstream had no effect. We found that acetoacetyl-CoA could overcome C75's inhibitory effect, whereas other FASN metabolites, including palmitate, did not prevent C75-mediated inhibition. This suggested an unexpected role for acetoacetyl-CoA in inflammation that is independent of its role in palmitate synthesis. Our evidence further suggested that acetoacetyl-CoA arising from FASN activity promotes cholesterol production, indicating a surprising link between fatty acid synthesis and cholesterol synthesis. We further demonstrate that this process is required for TLR4 to enter lipid rafts and facilitate TLR4 signaling. In conclusion, we have uncovered an unexpected link between FASN and cholesterol synthesis that appears to be required for TLR signal transduction and proinflammatory macrophage activation

Glutathione Transferase Omega-1 Regulates NLRP3 Inflammasome Activation through NEK7 Deglutathionylation

The NLRP3 inflammasome is a cytosolic complex sensing phagocytosed material and various damage-associated molecular patterns, triggering production of the pro-inflammatory cytokines interleukin-1 beta (IL)-1β and IL-18 and promoting pyroptosis. Here, we characterize glutathione transferase omega 1-1 (GSTO1-1), a constitutive deglutathionylating enzyme, as a regulator of the NLRP3 inflammasome. Using a small molecule inhibitor of GSTO1-1 termed C1-27, endogenous GSTO1-1 knockdown, and GSTO1-1−/− mice, we report that GSTO1-1 is involved in NLRP3 inflammasome activation. Mechanistically, GSTO1-1 deglutathionylates cysteine 253 in NIMA related kinase 7 (NEK7) to promote NLRP3 activation. We therefore identify GSTO1-1 as an NLRP3 inflammasome regulator, which has potential as a drug target to limit NLRP3-mediated inflammation.We would like to acknowledge the following grants: the National Health and Medical Research Council of Australia (NHMRC) is thanked for Project Grant APP1124673 to P.G.B., M.G.C., and L.A.J.O.; Principal Research Fellowship 1117602 to J.B.B.; and NHMRC Project Grant APP1156455 to J.B.B., P.G.B., and M.G.C. The O’Neill laboratory acknowledges the following grant support: European Research Council (ECFP7-ERC-MICROINNATE) and Science Foundation Ireland Investigator Award (SFI 12/IA/1531)

Itaconate is an anti-inflammatory metabolite that activates Nrf2 via alkylation of KEAP1.

The endogenous metabolite itaconate has recently emerged as a regulator of macrophage function, but its precise mechanism of action remains poorly understood. Here we show that itaconate is required for the activation of the anti-inflammatory transcription factor Nrf2 (also known as NFE2L2) by lipopolysaccharide in mouse and human macrophages. We find that itaconate directly modifies proteins via alkylation of cysteine residues. Itaconate alkylates cysteine residues 151, 257, 288, 273 and 297 on the protein KEAP1, enabling Nrf2 to increase the expression of downstream genes with anti-oxidant and anti-inflammatory capacities. The activation of Nrf2 is required for the anti-inflammatory action of itaconate. We describe the use of a new cell-permeable itaconate derivative, 4-octyl itaconate, which is protective against lipopolysaccharide-induced lethality in vivo and decreases cytokine production. We show that type I interferons boost the expression of Irg1 (also known as Acod1) and itaconate production. Furthermore, we find that itaconate production limits the type I interferon response, indicating a negative feedback loop that involves interferons and itaconate. Our findings demonstrate that itaconate is a crucial anti-inflammatory metabolite that acts via Nrf2 to limit inflammation and modulate type I interferons

The diversity of myeloid immune cells shaping wound repair and fibrosis in the lung

In healthy circumstances the immune system coordinates tissue repair responses in a tight balance that entails efficient inflammation for removal of potential threats, proper wound closure, and regeneration to regain tissue function. Pathological conditions, continuous exposure to noxious agents, and even ageing can dysregulate immune responses after injury. This dysregulation can lead to a chronic repair mechanism known as fibrosis. Alterations in wound healing can occur in many organs, but our focus lies with the lung as it requires highly regulated immune and repair responses with its continuous exposure to airborne threats. Dysregulated repair responses can lead to pulmonary fibrosis but the exact reason for its development is often not known. Here, we review the diversity of innate immune cells of myeloid origin that are involved in tissue repair and we illustrate how these cell types can contribute to the development of pulmonary fibrosis. Moreover, we briefly discuss the effect of age on innate immune responses and therefore on wound healing and we conclude with the implications of current knowledge on the avenues for future research

Competitive intramolecular carbenoid reactions of pyrrole derivatives

Rhodium(II) acetate-catalyzed decomposition of 1-diazo-3-phenyl-4-(pyrrol-1-yl)-butan-2-one and its p-methoxy derivative resulted in their intramolecular cyclization to form the 6-phenyl-5,6-dihydroindolizin-7(8H)-ones and 1-(pyrrol-1-yl)methylindan-3-ones as major and minor products respectively in high yields (77–89%). The p-nitrophenyldiazo compound cyclized exclusively to the 5,6-dihydroindolizin-7(8H)-one in 76% yield.</p