Deuterated Arachidonic Acid Ameliorates Lipopolysaccharide-Induced Lung Damage in Mice

Salidroside attenuates sepsis-induced acute lung injury by inhibiting ferroptosis-dependent pathway

Sepsis triggers a systemic inflammatory response that can lead to acute lung injury (ALI). Salidroside (SAL) has many pharmacological activities such as antiinflammatory and anti-oxidation. The objective of the study was to explore the mechanism of SAL on ALI caused by sepsis. A model of ALI in septic mice was established by cecal ligation and puncture. Following SAL treatment, the effect of SAL on the ferroptosis pathway in mice was analyzed. The pathological damage of lung tissue, the levels of inflammatory factors and apoptosis in bronchoalveolar lavage fluid (BALF) of mice were evaluated, and the changes of gene expression level and metabolite content abundance were explored by combining transcriptomics and metabolomics analysis. The effect of SAL on ferroptosis in mice with lung injury was observed by intraperitoneal injection of ferroptosis activator Erastin or ferroptosis inhibitor Ferrostatin-1 to promote or inhibit ferroptosis in mice. SAL significantly alleviated the pathological damage of lung tissue, decreased the number of TUNEL positive cells and the levels of TNF-α, IL-1β, IL-6 in BALF, and increased the level of IL- 10 in lung injury mice. Moreover, the Fe2+ content and malondialdehyde decreased significantly, the reactive oxygen species and glutathione content increased significantly, and the arachidonic acid metabolites 20-hydroxyeicosatetraenoic acid (20- HETE), (5Z, 8Z, 10E, 14Z)-12-Oxoeicosa-5,8,10,14-tetraenoic acid (12-OxOETE), (5Z, 8Z, 10E, 14Z)-(12S)-12-Hydroxyeicosa-5,8,10,14-tetraenoic acid (12(S)-HETE), (5Z, 8Z, 14Z)-11,12-Dihydroxyeicosa-5,8,14-trienoic acid (11,12-DHET), (5Z, 11Z, 14Z)-8,9- Dihydroxyeicosa-5,11,14-trienoic acid, Leukotriene B4, Leukotriene D4 were significantly up-regulated after SAL treatment. Salidroside alleviates ALI caused by sepsis by inhibiting ferroptosis.

Arachidonic acid: reconciling the dichotomy of its oxidative cascade through specific deuteration

A new approach to attenuating pathological inflammatory reactions by buffering the eicosanoid pathways with oxidation-resistant hexadeuterated arachidonic acid (D-ARA) is discussed. Enzymatic processing of ARA, released by phospholipase A2, by lipoxygenases, cyclooxygenases, and cytochromes yields a wide range of bioactive eicosanoids, including pro-inflammation, pro-angiogenesis and pro-thrombosis species that, when produced in excess, are an underlying cause of pathology. Conversely, some products of ARA oxidation possess pro-resolving properties. Non-enzymatic free radical oxidation of ARA generates another large group of products such as isoprostanes and their metabolites, associated with inflammation, ischemia-reperfusion stress, and atherosclerosis. A separate group comprises reactive carbonyl derivatives that irreversibly damage diverse biomolecules. Being resistant to both enzymatic and non-enzymatic oxidation pathways due to large kinetic isotope effects, D-ARA may play a role in mitigating inflammation-related disorders and conditions, including inflammaging.

Isolation, invitro, invivo anti-inflammatory, analgesic and antioxidant potential of Habenaria plantegania Lindl

Habenaira plantaginea belong to orchid family which is native to Asia. Members of this family are commonly famous for the cure of pain and inflammation. To date, no research was found on isolation of compounds from this plant for the treatment of inflammation and analgesia nor has been published to our knowledge. The purpose of this study was to evaluate an analgesic, anti-inflammatory and anti-oxidant activity of the isolated compound from the most potent chloroform sub-fraction and the isolated compounds form the habenaria plantaginea. Anti-inflammatory analgesic and antioxidant potential of the various chloroform sub-fractions and isolated compounds from the most potent sub-fraction (HP-1 & HP-1) were screened for their in vitro enzymatic assays. Furthermore, prior to in-vivo investigation, the isolated compounds were subjected for their toxicity study. The potent compound was then examined for acetic acid-induced writhing, hot plate test, carrageenan-induced inflammation assays. Further various phlogistic agents were used for the evaluation of mechanism. In the COX-2 inhibitory assay the chloroform sub fraction Cf-4 demonstrated excellent activity as compared to the other sub-fraction with 92.15% inhibition. The COX-2 enzyme make prostaglandins which are directly involved in inflammation. Likewise against 5-LOX the Cf-4 was the most potent sub-fraction with IC50 3.77 µg/mL. The 5-LOX catalyzes the biosynthesis of leukotrienes which is a group of lipid mediators of inflammation derived from arachidonic acid. Free radicals can induce inflammation through cellular damage while chronic inflammation generates a large number of free radicals, whose eventually lead to inflammation. In antioxidant assays the Cf-4 fraction was displayed excellent results against ABTS, DPPH and H2O2 free radical with 88.88, 77.44, and 65.52% inhibition at highest concentration. Likewise, the compound HP-1 demonstrated 88.81, 89.34 and 80.43% inhibition while compound HP-2 displayed 84.34, 91.52 and 82.34% inhibition against ABTS, DPPH and H2O2 free radical which were comparable to the standard drug ascorbic acid respectively. This study's findings validate the use of this species as traditional use.

Arachidonic acid modulates the cellular energetics of human pluripotent stem cells and protects the embryoid bodies from embryotoxicity effects in vitro

Arachidonic acid (AA), an ω-6 polyunsaturated fatty acid involved in signalling pathways that drive cell fate decisions, has an enhancing role in the immunomodulatory effect on mesenchymal stem cells and the vasculogenesis of embryonic stem cells. 3D embryoid bodies (EBs) from pluripotent stem cells (PSCs) have been used as in vitro models for embryotoxicity for various compounds/drugs. Valproic acid (VA), a common anti-epileptic drug, is known to be embryotoxic and cause malformations in embryos. As early embryogenesis depends on AA, we investigated the embryo protective effects of AA against the embryotoxic drug VA in this study. The effects of AA on the proliferation and cell cycle parameters of PSCs were studied. In particular, the potential of AA to abrogate VA-induced embryotoxicity in vitro was evaluated using ROS detection and antioxidant assays. In response to AA, we observed modulation in cell proliferation of induced pluripotent stem cells (iPSCs) and pluripotent NTERA-2 embryonal carcinoma (EC) cells. The present study substantiates the cytoprotective effects of AA against VA. These results imply that AA plays a critical role in the proliferation and differentiation of iPSCs and EC cells and protects the EBs from cytotoxic damage, thereby ensuring normal embryogenesis. Thus, the bioactive lipid AA may be explored for supplementation to benefit pregnant women treated with long-term anti-epileptic drugs to prevent in-utero fetal growth malformations.

Association between circulating fatty acid metabolites and asthma risk: a two-sample bidirectional Mendelian randomization study

BACKGROUND

Fatty acids are involved in a wide range of immunological responses in humans. Supplementation of polyunsaturated fatty acids has been reported to help alleviate symptoms and airway inflammation in asthma patients, whereas the effects of fatty acids on the actual risk of asthma remain controversial. This study comprehensively investigated the causal effects of serum fatty acids on asthma risk using two-sample bidirectional Mendelian Randomization (MR) analysis.

METHODS

Genetic variants strongly associated with 123 circulating fatty acid metabolites were extracted as instrumental variables, and a large GWAS data of asthma was used to test effects of the metabolites on this outcome. The inverse-variance weighted method was used for primary MR analysis. The weighted median, MR-Egger regression, MR-PRESSO, and leave-one-out analyses were utilized to evaluate heterogeneity and pleiotropy. Potential confounders were adjusted by performing multivariable MR analyses. Reverse MR analysis was also conducted to estimate the causal effect of asthma on candidate fatty acid metabolites. Further, we performed colocalization analysis to examine the pleiotropy of variants within the fatty acid desaturase 1 (FADS1) locus between the significant metabolite traits and the risk of asthma. Cis-eQTL-MR and colocalization analysis were also performed to determine the association between RNA expression of FADS1 and asthma.

RESULTS

Genetically instrumented higher average number of methylene groups was causally associated with a lower risk of asthma in primary MR analysis, while inversely, the higher ratio of bis-allylic groups to double bonds and the higher ratio of bis-allylic groups to total fatty acids, were associated with higher probabilities of asthma. Consistent results were obtained in multivariable MR when adjusted for potential confounders. However, these effects were completely eliminated after SNPs correlated with the FADS1 gene were excluded. The reverse MR also found no causal association. The colocalization analysis suggested that the three candidate metabolite traits and asthma likely share causal variants within the FADS1 locus. In addition, the cis-eQTL-MR and colocalization analyses demonstrated a causal association and shared causal variants between FADS1 expression and asthma.

CONCLUSIONS

Our study supports a negative association between several PUFA traits and the risk of asthma. However, this association is largely attributed to the influence of FADS1 polymorphisms. The results of this MR study should be carefully interpreted given the pleiotropy of SNPs associated with FADS1.

Deuterated Drugs and Biomarkers in the COVID-19 Pandemic

Coronavirus disease 2019 (COVID-19) is a highly contagious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Initially identified in Wuhan (China) in December 2019, COVID-19 rapidly spread globally, resulting in the COVID-19 pandemic. Carriers of the SARS-CoV-2 can experience symptoms ranging from mild to severe (or no symptoms whatsoever). Although vaccination provides extra immunity toward SARS-CoV-2, there has been an urgent need to develop treatments for COVID-19 to alleviate symptoms for carriers of the disease. In seeking a potential treatment, deuterated compounds have played a critical role either as therapeutic agents or as internal MS standards for studying the pharmacological properties of new drugs by quantifying the parent compounds and metabolites. We have identified >70 examples of deuterium-labeled compounds associated with treatment of COVID-19. Of these, we found 9 repurposed drugs and >20 novel drugs studied for potential therapeutic roles along with a total of 38 compounds (drugs, biomarkers, and lipids) explored as internal mass spectrometry standards. This review details the synthetic pathways and modes of action of these compounds (if known), and a brief analysis of each study.