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Lahens, N.

Publications and source records attributed to Lahens, N..

5 recordsLinked to original sources

Metabolomic Response to Non-Steroidal Anti-Inflammatory Drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are popular choices for the mitigation of pain and inflammation; however, they are accompanied by side effects in the gastrointestinal and cardiovascular systems. We compared the effects of naproxen, a traditional NSAID, and celecoxib, a cyclooxygenase -2 (Cox-2) inhibitor, in humans. Our findings showed a decrease in tryptophan and kynurenine levels in plasma of volunteers treated with naproxen. We further validated this result in mice. Additionally, we find that the depression of tryptophan was independent of both Cox-1 and Cox-2 inhibition, but rather was due to the displacement of bound tryptophan by naproxen. Supplementation of tryptophan in naproxen-treated mice rescued fecal blood loss and inflammatory gene expression driven by IL-1{beta} in the heart.

systems biology↗

Cyclooxygenase-2 disruption predisposes to heart failure with preserved ejection fraction

Heart failure (HF) is one of the most strongly associated adverse cardiovascular events linked to the use of cyclooxygenase (COX)-2 selective and non-selective nonsteroidal anti-inflammatory drug (NSAID). Nevertheless, it remains uncertain whether NSAID exposure is more likely to lead to heart failure with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF). In adult mice, postnatal genetic deletion or pharmacological inhibition of COX-2 did not affect cardiac function. In contrast, aged female inducible COX-2 (iCOX-2) knockout (KO) mice displayed diastolic dysfunction, cardiac hypertrophy, pulmonary congestion, and elevated levels of plasma N-terminal pro B-type natriuretic peptide (BNP) when compared to age- and sex- matched controls, while their ejection fraction (EF) remained preserved ([≥] 50%). No such phenotype was observed in aged male iCox-2 KO mice. Aged female iCox-2 KO mice showed a shift from prostanoid to leukotriene biosynthesis, along with changes in the expression of mitochondrial genes and calcium-handling proteins in the myocardium. The ratio of phospholamban to SERCA2a was increased, indicating an inhibitory effect on SERCA2a activity, which may contribute to impaired myocardial relaxation. In larval zebrafish, COX-2 inhibition by celecoxib caused a modest yet significant reduction in heart rate and diastolic function, while EF was preserved. Additionally, celecoxib increased BNP expression and ventricular calcium transient amplitude. Diabetic patients in the Harvard-Partners electronic medical record exposed to NSAIDs selective for COX-2 inhibition were more strongly associated with an increased risk of HFpEF compared to HFrEF. Collectively, these findings indicate that COX-2 deletion or inhibition does not impair systolic cardiac function but instead leads to an HFpEF phenotype in mice, zebrafish, and humans. An imbalance in calcium handling may mediate the impairment of myocardial relaxation following COX-2 suppression. SummaryGenetic deletion or pharmacological inhibition of COX-2 results in heart failure with preserved ejection fraction across zebrafish, mice, and humans.

pharmacology and toxicology↗

Deep Phenotyping of the Lipidomic Response in COVID and non-COVID Sepsis

Lipids may influence cellular penetrance by pathogens and the immune response that they evoke. Here we find a broad based lipidomic storm driven predominantly by secretory (s) phospholipase A2 (sPLA2) dependent eicosanoid production occurs in patients with sepsis of viral and bacterial origin and relates to disease severity in COVID-19. Elevations in the cyclooxygenase (COX) products of arachidonic acid (AA), PGD2 and PGI2, and the AA lipoxygenase (LOX) product, 12-HETE, and a reduction in the high abundance lipids, ChoE 18:3, LPC-O-16:0 and PC-O-30:0 exhibit relative specificity for COVID-19 amongst such patients, correlate with the inflammatory response and link to disease severity. Linoleic acid (LA) binds directly to SARS-CoV-2 and both LA and its di-HOME products reflect disease severity in COVID-19. AA and LA metabolites and LPC-O-16:0 linked variably to the immune response. These studies yield prognostic biomarkers and therapeutic targets for patients with sepsis, including COVID-19. An interactive purpose built interactive network analysis tool was developed, allowing the community to interrogate connections across these multiomic data and generate novel hypotheses.

systems biology↗

MOCCASIN: A method for correcting for known and unknown confounders in RNA splicing analysis

While the effects of confounders on gene expression analysis have been extensively studied there is a lack of equivalent analysis and tools for RNA splicing analysis. Here we assess the effect of confounders in two large public RNA-Seq datasets (TARGET, ENCODE), develop a new method, MOCCASIN, to correct the effect of both known and unknown confounders on RNA splicing quantification, and demonstrate MOCCASINs effectiveness on both synthetic and real data.

genomics↗

Iso-relevance Functions - A Systematic Approach to Ranking Genomic Features by Differential Effect Size

It is common to measure large numbers of features to identify those differing between experimental conditions; for example using RNA-Seq to search for differentially expressed genes. Ranking by p-value allows for statistical control, but has well known issues: unreliability without many replicates; and significance of biologically irrelevant effect sizes. As a result prioritization is typically performed in conjunction with effect size; the canonical one being "fold-change" [Formula]. However fold-change has several issues: division by zero, sensitivity to small values in the denominator, insensitivity to magnitude (1 over 2 equals 100 over 200). To mitigate these problems adding 1 to all values is a widely used heuristic; which we show using real and simulated data is typically highly sub-optimal, while the value 20 is nearly optimal in all cases. From another point of view, adding a fixed "pseudocount" to all values is essentially re-defining effect size from fold-change to something else. To explore this further, we axiomatize the concept of effect size and use this mathematical framework to study the problem in general. We also present the remarkable finding that pseudocounts strike a balance between sorting by fold-change and sorting by difference. Therefore, optimization is equivalent to finding the most harmonious balance between these two extremes. Lastly, the framework is illustrated on a fundamentally different type of problem, that of ranking di-codons by their differential abundance in the ORFeome of different species, where p-values are unavailable and one must solve the problem directly with effect sizes.

bioinformatics↗