Vegetative and Climatic Controls on Holocene Wildfire and Erosion Recorded in Alluvial Fans of the Middle Fork Salmon River, Idaho

The Middle Fork Salmon River watershed spans high-elevation mixed-conifer forests to lower-elevation shrub-steppe. In recent decades, runoff from severely burned hillslopes has generated large debris flows in steep tributary drainages. These flows incised alluvial fans along the mainstem river, where charcoal-rich debris-flow and sheetflood deposits preserve a record of latest Pleistocene to Holocene fires and geomorphic response. Through deposit sedimentology and 14C dating of charcoal, we evaluate the processes and timing of fire-related sedimentation and the role of climate and vegetation change. Fire-related deposits compose ~66% of the total measured fan deposit thickness in more densely forested upper basins versus ~33% in shrub-steppe-dominated lower basins. Fires during the middle Holocene (~8000 - 5000 cal yr BP) mostly resulted in sheetflood deposition, similar to modern events in lower basins. Decreased vegetation density during this generally warmer and drier period likely resulted in lower-severity fires and more frequent but smaller fire-related sedimentation events. In contrast, thick fire-related debris-flow deposits of latest Pleistocene-early Holocene (~13,500-8000 cal yr BP) and late Holocene (\u3c 4000 cal yr BP) age are inferred to represent higher-severity fires, though data in the former period are limited. Widespread fires occurred in both upper and lower basins within the Medieval Climatic Anomaly (1050-650 cal yr BP) and the early Little Ice Age ca. 550 cal yr BP. We conclude that a generally cooler late Holocene climate and a shift to denser lodgepole pine forests in upper basins by ~2500 cal yr BP provided fuel for severe fires during episodic droughts

EGLN1 Inhibition and Rerouting of α-Ketoglutarate Suffice for Remote Ischemic Protection

Ischemic preconditioning is the phenomenon whereby brief periods of sublethal ischemia protect against a subsequent, more prolonged, ischemic insult. In remote ischemic preconditioning (RIPC), ischemia to one organ protects others organs at a distance. We created mouse models to ask if inhibition of the alpha-ketoglutarate (αKG)-dependent dioxygenase Egln1, which senses oxygen and regulates the hypoxia-inducible factor (HIF) transcription factor, could suffice to mediate local and remote ischemic preconditioning. Using somatic gene deletion and a pharmacological inhibitor, we found that inhibiting Egln1 systemically or in skeletal muscles protects mice against myocardial ischemia-reperfusion (I/R) injury. Parabiosis experiments confirmed that RIPC in this latter model was mediated by a secreted factor. Egln1 loss causes accumulation of circulating αKG, which drives hepatic production and secretion of kynurenic acid (KYNA) that is necessary and sufficient to mediate cardiac ischemic protection in this setting.Broad Institute of MIT and Harvard. SPARC ProgramBurroughs Wellcome Fun

Adaptive NK cells in people exposed to Plasmodium falciparum correlate with protection from malaria

How antibodies naturally acquired during Plasmodium falciparum infection provide clinical immunity to blood-stage malaria is unclear. We studied the function of natural killer (NK) cells in people living in a malaria-endemic region of Mali. Multi-parameter flow cytometry revealed a high proportion of adaptive NK cells, which are defined by the loss of transcription factor PLZF and Fc receptor γ-chain. Adaptive NK cells dominated antibody-dependent cellular cytotoxicity responses, and their frequency within total NK cells correlated with lower parasitemia and resistance to malaria. P. falciparum–infected RBCs induced NK cell degranulation after addition of plasma from malaria-resistant individuals. Malaria-susceptible subjects with the largest increase in PLZF-negative NK cells during the transmission season had improved odds of resistance during the subsequent season. Thus, antibody-dependent lysis of P. falciparum–infected RBCs by NK cells may be a mechanism of acquired immunity to malaria. Consideration of antibody-dependent NK cell responses to P. falciparum antigens is therefore warranted in the design of malaria vaccines

Metabolomics of Chronic Kidney Disease Progression: A Case-Control Analysis in the Chronic Renal Insufficiency Cohort Study

Whereas several longitudinal metabolomics studies have been conducted in individuals with normal eGFR at baseline, disease progression among individuals with established CKD has not been rigorously examined

Environment Impacts the Metabolic Dependencies of Ras-Driven Non-Small Cell Lung Cancer

Cultured cells convert glucose to lactate, and glutamine is the major source of tricarboxylic acid (TCA)-cycle carbon, but whether the same metabolic phenotype is found in tumors is less studied. We infused mice with lung cancers with isotope-labeled glucose or glutamine and compared the fate of these nutrients in tumor and normal tissue. As expected, lung tumors exhibit increased lactate production from glucose. However, glutamine utilization by both lung tumors and normal lung was minimal, with lung tumors showing increased glucose contribution to the TCA cycle relative to normal lung tissue. Deletion of enzymes involved in glucose oxidation demonstrates that glucose carbon contribution to the TCA cycle is required for tumor formation. These data suggest that understanding nutrient utilization by tumors can predict metabolic dependencies of cancers in vivo. Furthermore, these data argue that the in vivo environment is an important determinant of the metabolic phenotype of cancer cells.National Science Foundation (U.S.) (Grant T32GM007287

Prediagnostic plasma metabolomics and the risk of amyotrophic lateral sclerosis

Objective: To identify prediagnostic plasma metabolomic biomarkers associated with amyotrophic lateral sclerosis (ALS). Methods: We conducted a global metabolomic study using a nested case-control study design within 5 prospective cohorts and identified 275 individuals who developed ALS during follow-up. We profiled plasma metabolites using liquid chromatography–mass spectrometry and identified 404 known metabolites. We used conditional logistic regression to evaluate the associations between metabolites and ALS risk. Further, we used machine learning analyses to determine whether the prediagnostic metabolomic profile could discriminate ALS cases from controls. Results: A total of 31 out of 404 identified metabolites were associated with ALS risk (p < 0.05). We observed inverse associations (n = 27) with plasma levels of diacylglycerides and triacylglycerides, urate, purine nucleosides, and some organic acids and derivatives, while we found positive associations for a cholesteryl ester, 2 phosphatidylcholines, and a sphingomyelin. The number of significant associations increased to 67 (63 inverse) in analyses restricted to cases with blood samples collected within 5 years of onset. None of these associations remained significant after multiple comparison adjustment. Further, we were not able to reliably distinguish individuals who became cases from controls based on their metabolomic profile using partial least squares discriminant analysis, elastic net regression, random forest, support vector machine, or weighted correlation network analyses. Conclusions: Although the metabolomic profile in blood samples collected years before ALS diagnosis did not reliably separate presymptomatic ALS cases from controls, our results suggest that ALS is preceded by a broad, but poorly defined, metabolic dysregulation years before the disease onset

Lysine pathway metabolites and the risk of type 2 diabetes and cardiovascular disease in the PREDIMED study: results from two case-cohort studies

Background: The pandemic of cardiovascular disease (CVD) and type 2 diabetes (T2D) requires the identifcation of new predictor biomarkers. Biomarkers potentially modifable with lifestyle changes deserve a special interest. Our aims were to analyze: (a) The associations of lysine, 2-aminoadipic acid (2-AAA) or pipecolic acid with the risk of T2D or CVD in the PREDIMED trial; (b) the efect of the dietary intervention on 1-year changes in these metabolites, and (c) whether the Mediterranean diet (MedDiet) interventions can modify the efects of these metabolites on CVD or T2D risk. Methods: Two unstratifed case-cohort studies nested within the PREDIMED trial were used. For CVD analyses, we selected 696 non-cases and 221 incident CVD cases; for T2D, we included 610 non-cases and 243 type 2 diabetes incident cases. Metabolites were quantifed using liquid chromatography–tandem mass spectrometry, at baseline and after 1-year of intervention. Results: In weighted Cox regression models, we found that baseline lysine (HR+1 SD increase=1.26; 95% CI 1.06–1.51) and 2-AAA (HR+1 SD increase=1.28; 95% CI 1.05–1.55) were both associated with a higher risk of T2D, but not with CVD. A signifcant interaction (p=0.032) between baseline lysine and T2D on the risk of CVD was observed: subjects with prevalent T2D and high levels of lysine exhibited the highest risk of CVD. The intervention with MedDiet did not have a signifcant efect on 1-year changes of the metabolites. Conclusions: Our results provide an independent prospective replication of the association of 2-AAA with future risk of T2D. We show an association of lysine with subsequent CVD risk, which is apparently diabetes-dependent. No evidence of efects of MedDiet intervention on lysine, 2-AAA or pipecolic acid changes was found

Mitochondrial ROS regulate thermogenic energy expenditure and sulfenylation of UCP1

Brown adipose tissue (BAT) can dissipate chemical energy as heat through thermogenic respiration, which requires uncoupling protein 1 (UCP1)1,2. Thermogenesis from BAT and beige adipose can combat obesity and diabetes3, encouraging investigation of factors that control UCP1-dependent respiration in vivo. Herein we show that acutely activated BAT thermogenesis is defined by a substantial increase in mitochondrial reactive oxygen species (ROS) levels. Remarkably, this process supports in vivo BAT thermogenesis, as pharmacological depletion of mitochondrial ROS results in hypothermia upon cold exposure, and inhibits UCP1-dependent increases in whole body energy expenditure. We further establish that thermogenic ROS alter BAT cysteine thiol redox status to drive increased respiration, and Cys253 of UCP1 is a key target. UCP1 Cys253 is sulfenylated during thermogenesis, while mutation of this site desensitizes the purine nucleotide inhibited state of the carrier to adrenergic activation and uncoupling. These studies identify BAT mitochondrial ROS induction as a mechanism that drives UCP1-dependent thermogenesis and whole body energy expenditure, which opens the way to develop improved therapeutic strategies for combating metabolic disorders

Computational Modelling of Tissue-Engineered Cartilage Constructs

Cartilage is a fundamental tissue to ensure proper motion between bones and damping of mechanical loads. This tissue often suffers damage and has limited healing capacity due to its avascularity. In order to replace surgery and replacement of joints by metal implants, tissue engineered cartilage is seen as an attractive alternative. These tissues are obtained by seeding chondrocytes or mesenchymal stem cells in scaffolds and are given certain stimuli to improve establishment of mechanical properties similar to the native cartilage. However, tissues with ideal mechanical properties were not obtained yet. Computational models of tissue engineered cartilage growth and remodelling are invaluable to interpret and predict the effects of experimental designs. The current model contribution in the field will be presented in this chapter, with a focus on the response to mechanical stimulation, and the development of fully coupled modelling approaches incorporating simultaneously solute transport and uptake, cell growth, production of extracellular matrix and remodelling of mechanical properties.publishe