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Chronic inflammation is a common feature of obesity, with elevated cytokines such as interleukin-1 (IL-1) in the circulation and tissues. Here, we report an unconventional IL-1R–MyD88–IRAK2–PHB/OPA1 signaling axis that reprograms mitochondrial metabolism in adipocytes to exacerbate obesity. IL-1 induced recruitment of IRAK2 Myddosome to mitochondria outer membranes via recognition by TOM20, followed by TIMM50-guided translocation of IRAK2 into mitochondria inner membranes, to suppress oxidative phosphorylation and fatty acid oxidation, thereby attenuating energy expenditure. Adipocyte-specific MyD88 or IRAK2 deficiency reduced high-fat-diet-induced weight gain, increased energy expenditure and ameliorated insulin resistance, associated with a smaller adipocyte size and increased cristae formation. IRAK2 kinase inactivation also reduced high-fat diet-induced metabolic diseases. Mechanistically, IRAK2 suppressed respiratory super-complex formation via interaction with PHB1 and OPA1 upon stimulation of IL-1. Taken together, our results suggest that the IRAK2 Myddosome functions as a critical link between inflammation and metabolism, representing a novel therapeutic target for patients with obesity. Obesity is often accompanied by chronic inflammation. Li and colleagues show that, in mice fed high-fat diets, IL-1 signaling in adipocytes induces an unconventional IRAK2 translocation to mitochondria and suppresses respiratory super-complex formation to alter mitochondrial function, and exacerbates obesity.

Group 1 pulmonary hypertension (PH), i.e., pulmonary arterial hypertension (PAH), is associated with a metabolic shift favoring glycolysis in cells comprising the lung vasculature as well as skeletal muscle and right heart. We sought to determine whether this metabolic switch is also detectable in circulating platelets from PAH patients. We used Seahorse Extracellular Flux to measure bioenergetics in platelets isolated from group 1 PH (PAH), group 2 PH, patients with dyspnea and normal pulmonary artery pressures, and healthy controls. We show that platelets from group 1 PH patients exhibit enhanced basal glycolysis and lower glycolytic reserve compared with platelets from healthy controls but do not differ from platelets of group 2 PH or dyspnea patients without PH. Although we were unable to identify a glycolytic phenotype unique to platelets from PAH patients, we found that platelet glycolytic metabolism correlated with hemodynamic severity only in group 1 PH patients, supporting the known link between PAH pathology and altered glycolytic metabolism and extending this association to ex vivo platelets. Pulmonary artery pressure and pulmonary vascular resistance in patients with group 1 PH were directly associated with basal platelet glycolysis and inversely associated with maximal and reserve glycolysis, suggesting that PAH progression reduces the capacity for glycolysis even while demanding an increase in glycolytic metabolism. Therefore, platelets may provide an easy-to-harvest, real-time window into the metabolic shift occurring in the lung vasculature and represent a useful surrogate for interrogating the glycolytic shift central to PAH pathology.

Objective Breakthroughs in HIV treatment, especially combination antiretroviral therapy (ART), have massively reduced AIDS-associated mortality. However, ART administration amplifies the risk of non-AIDS defining illnesses including obesity, diabetes, and cardiovascular disease, collectively known as metabolic syndrome. Initial reports suggest that ART-associated risk of metabolic syndrome correlates with socioeconomic status, a multifaceted finding that encompasses income, race, education, and diet. Therefore, determination of causal relationships is extremely challenging due to the complex interplay between viral infection, ART, and the many environmental factors. Methods In the current study, we employed a mouse model to specifically examine interactions between ART and diet that impacts energy balance and glucose metabolism. Previous studies have shown that high-fat feeding induces persistent low-grade systemic and adipose tissue inflammation contributing to insulin resistance and metabolic dysregulation via adipose-infiltrating macrophages. Studies herein test the hypothesis that ART potentiates the inflammatory effects of a high-fat diet (HFD). C57Bl/6J mice on a HFD or standard chow containing ART or vehicle, were subjected to functional metabolic testing, RNA-sequencing of epididymal white adipose tissue (eWAT), and array-based kinomic analysis of eWAT-infiltrating macrophages. Results ART-treated mice on a HFD displayed increased fat mass accumulation, impaired glucose tolerance, and potentiated insulin resistance. Gene set enrichment and kinomic array analyses revealed a pro-inflammatory transcriptional signature depicting granulocyte migration and activation. Conclusion The current study reveals a HFD-ART interaction that increases inflammatory transcriptional pathways and impairs glucose metabolism, energy balance, and metabolic dysfunction., Graphical abstract Image 1, Highlights • Antiretroviral therapy (ART) exacerbates high-fat diet induced obesity and dysregulation of glucose homeostasis. • Transcriptomic and Kinomic analyses identify increased pro-inflammatory, adipose-tissue macrophages after ART-treatment. • ART and high-fat diet synergistically induce the G-protein coupled receptor, Gpr50, in white adipose tissue.

Light may influence grazing through its effect on grazers or by influencing the physiology and biochemistry of primary producers. It has recently been established that reactive oxygen species (ROS) produced by a wounded macroalga depend on light via photosynthetic electron transport. Since ROS can act as both chemical messengers and toxins, it is hypothesized that the light-dependence of wound-induced ROS can have ecological consequences for plant–herbivore interactions. Through spin trapping and electron paramagnetic resonance, this study shows that wounded Ascoseira mirabilis produced ROS that were correlated with A. mirabilis wounding in light but not dark conditions. In feeding assays where sympatric amphipods consumed palatable macroalgae in the presence of wounded A. mirabilis, amphipod consumption was correlated with A. mirabilis wounding in light but not dark conditions. The nonlinear effect of ROS on grazing suggests that in ecology, as in physiology, low levels of ROS may act as messengers while high levels are toxic.

Reactive oxygen species (ROS) produced by an oxidative burst are an important component of the wound response in algae, vascular plants, and animals. In all taxa, ROS production is usually attributed solely to a defense-related enzyme like NADPH-oxidase (Nox). However, here we show that the initial, wound-induced oxidative burst of the kelp Saccharina latissima depends on light and photosynthetic electron transport. We measured oxygen evolution and ROS production at different light levels and in the presence of a photosynthetic inhibitor, and we used spin trapping and electron paramagnetic resonance as an orthogonal method. Using an in vivo chemical probe, we provide data suggesting that wound-induced ROS production in two distantly related and geographically isolated species of Antarctic macroalgae may be light dependent as well. We propose that electron transport chains are an important and as yet unaddressed component of the wound response, not just for photosynthetic organisms, but for animals via mitochondria as well. This component may have been obscured by the historic use of diphenylene iodonium, which inhibits not only Noxes but also photosynthetic and respiratory electron transport as well. Finally, we anticipate physiological and/or ecological consequences of the light dependence of macroalgal wound-induced ROS since pathogens and grazers do not disappear in the dark.

Marine macroalgae can release reactive oxygen species (ROS) upon wounding and grazing. Here we address the potential role of ROS in herbivore defense. We performed feeding assays in the presence of varying concentrations of hydrogen peroxide (H2O2), a common type of ROS. H2O2 inhibited feeding by a marine amphipod grazer, Gondogeneia antarctica, over broad levels of concentration, and its potency was strongly dependent on its rate of decay in natural seawater. Because it is possible that the inhibitory levels of H2O2 are encountered in the vicinity of a sympatric macroalgal wound, we suggest that H2O2 has the potential to act as a direct anti-grazing defense in marine ecosystems. Since some sympatric macroalgae release a burst of non-H2O2 ROS, we also performed experiments to evaluate the role of these naturally-produced ROS on sympatric grazers. The presence of wounded Ascoseira mirabilis (which releases a burst of non-H2O2 ROS after wounding) during a feeding assay inhibited feeding of G. antarctica compared to the presence of intact A. mirabilis. These data are consistent with a role for ROS as a direct anti-herbivore defense in nature. However, the data are also consistent with hypotheses that involve other putative activated anti-grazing defenses.

Reactive oxygen species (ROS) are commonly produced by algal, vascular plant, and animal cells involved in the innate immune response as cellular signals promoting defense and healing and/or as a direct defense against invading pathogens. The production of reactive species in macroalgae upon injury, however, is largely uncharacterized. In this study, we surveyed 13 species of macroalgae from the Western Antarctic Peninsula and show that the release of strong oxidants is common after macroalgal wounding. Most species released strong oxidants within 1 min of wounding and/or showed cellular accumulation of strong oxidants over an hour post-wounding. Exogenous catalase was used to show that hydrogen peroxide was a component of immediate oxidant release in one of five species, but was not responsible for the entire oxidative wound response as is common in vascular plants. The other component(s) of the oxidant cocktail released upon wounding are unknown. We were unable to detect protein nitration in extracts of four oxidant-producing species flash frozen 30 s after wounding, but a role for reactive nitrogen species such as peroxynitrite cannot be completely ruled out. Two species showed evidence for the production of a catalase-activated oxidant, a mechanism previously known only from the laboratory and from the synthetic drug isoniazid used to kill the human pathogen Mycobacterium tuberculosis. The rhodophyte Palmaria decipiens, which released strong oxidants after wounding, also produced strong oxidants upon grazing by a sympatric amphipod, suggesting that oxidants are involved in the response to grazing.

Harvest restrictions by sex or reproductive status are used to protect many spawning stocks. In most U.S. states, fishery regulations for blue crabs Callinectes sapidus require release of ovigerous crabs. Ovigerous crabs caught in pots become stressed by capture and physically damage the egg mass and remove eggs. We conducted a survey to assess the extent of egg mass damage in pot-caught crabs as well as crabs caught by hand and not subjected to pot stress. Egg mass damage was more prevalent in pot-caught crabs (>45% during all months) than in crabs caught by hand (

We examined lifetime clutch production and size at maturity for blue crabs Callinectes sapidus Rathbun in North Carolina, USA. Female crabs were collected at terminal molt and confined individually in the field for the duration of their lifetime. Crabs were monitored weekly for the pres- ence of eggs. Clutch quality and larval viability were assessed for each clutch. Crabs produced up to 7 clutches over 1 to 2 spawning seasons and survived up to 394 d after the terminal molt. Time to first clutch and time between clutches were positively correlated with carapace width and best described by degree-days, physiological time calculated as a thermal integral. Size at maturity was negatively correlated with water temperature on the day of the terminal molt. Egg lipid content (mean = 79.2% of dry mass), egg diameter (mean = 267.5 µm), larval carapace width (mean = 278.4 µm), and larval survival time without food (mean = 3.4 d) were similar for all clutches. The percentage of embryos developing normally decreased 40% from Clutch 1 to 4, and clutch volume decreased 50% from Clutch 1 to 5. Thus, most of a crab's reproductive output is from the first few clutches. Realistic esti- mates of fecundity and reproductive potential are essential for accurate spawning stock assessment and population modeling.

Mitochondrial (mito) bioenergetics of circulating cells change as a function of disease in Alzheimer’s, fibromyalgia, cancer, and Type 2 diabetes. We are exploring the use of mito-bioenergetics as a biomarker of Type 1 diabetes (T1D) progression and immune cell activation. T1D is a polygenic autoimmune disease in which an inflammatory leukocytic infiltrate into pancreatic islets results in destruction of insulin-producing β-cells. Autoantibody synthesis is currently used as a biomarker, but is a poor predictor of T1D since the majority of β-cells are destroyed prior to autoantibody seroconversion. We hypothesize that T1D is a chronic inflammatory disease in which conditions of oxidative stress will diminish the mitochondrial reserve capacity of immune cells and provide a surrogate marker for T1D. We compared mito-bioenergetics of murine immune cells derived from the spleen, pancreatic lymph node and bone marrow between diabetic and pre-diabetic Non-Obese Diabetic (NOD) mice. We show that mitochondrial reserve capacity is reduced in circulating CD4+ T cells from diabetic mice, but not in pre-diabetic mice during T1D progression. To explore the role of mitochondrial oxidative stress on diabetogenic CD4+ T cell effector responses, we used mito-TEMPO to scavenge mitochondrial reactive oxygen species (mROS). Mito-TEMPO reduced IFNγ synthesis in a primary recall assay by 0.24-fold and the combination of mito and cytosolic TEMPO increased Treg-associated IL-2 by 2.5-fold, suggesting that mROS have a causal role in modulating T cell effector responses critical for T1D pathology. We plan to perform human translational studies on mito-bioenergetics of PBMCs from recent onset T1D patients and further dissect the role of mROS on T1D.