Arachidonic Acid Metabolite 19(S)-HETE Induces Vasorelaxation and Platelet Inhibition by Activating Prostacyclin (IP) Receptor

Enantioselectivity in some physiological and pathophysiological roles of hydroxyeicosatetraenoic acids

The phenomenon of chirality has been shown to greatly impact drug activities and effects. Different enantiomers may exhibit different effects in a certain biological condition or disease state. Cytochrome P450 (CYP) enzymes metabolize arachidonic acid (AA) into a large variety of metabolites with a wide range of activities. Hydroxylation of AA by CYP hydroxylases produces hydroxyeicosatetraenoic acids (HETEs), which are classified into mid-chain (5, 8, 9, 11, 12, and 15-HETE), subterminal (16-, 17-, 18- and 19-HETE) and terminal (20-HETE) HETEs. Except for 20-HETE, these metabolites exist as a racemic mixture of R and S enantiomers in the physiological system. The two enantiomers could have different degrees of activity or sometimes opposing effects. In this review article, we aimed to discuss the role of mid-chain and subterminal HETEs in different organs, importantly the heart and the kidneys. Moreover, we summarized their effects in some conditions such as neutrophil migration, inflammation, angiogenesis, and tumorigenesis, with a focus on the reported enantiospecific effects. We also reported some studies using genetically modified models to investigate the roles of HETEs in different conditions.

Astragalus membranaceus and Salvia miltiorrhiza ameliorate diabetic kidney disease via the "gut-kidney axis"

BACKGROUND

The combination of Astragalus membranaceus and Salvia miltiorrhiza (AS) is an effective prescription for treating diabetic kidney disease (DKD) in traditional Chinese medicine. Its efficacy in treating DKD has been confirmed, but the potential regulatory mechanism has not yet been fully clarified.

PURPOSE

To explore the mechanism by which AS regulates the "gut-metabolism-transcription" coexpression network under the action of the "gut-kidney axis" to ameliorate DKD.

METHODS

SD rats were used to establish the DKD model by injecting STZ. After AS intervention, the structure and function of the kidney and colon were observed. We sequenced the gut microbiota utilizing 16S rDNA, identified serum differential metabolites using LC‒MS/MS, and observed renal mRNA expression by RNA seq. The "gut-metabolism-transcription" coexpression network was further constructed, and the target bacteria, target metabolites, and target genes of AS were ultimately screened and validated.

RESULTS

AS improved renal pathology and functional damage and increased the abundance of Akkermansia, Akkermansia_muciniphila, Lactobacillus and Lactobacillus_murinus. Fourteen target metabolites of AS were identified, which were mainly concentrated in 19 KEGG pathways, including sphingolipid metabolism and glycerophospholipid metabolism. Sixty-three target mRNAs of AS were identified. The top 20 pathways were closely related to glycolipid metabolism, and 14 differential mRNAs were expressed in these pathways. Correlation analysis showed that Akkermansia, Akkermansia muciniphila, Lactobacillus and Lactobacillus murinus were closely associated with sphingolipid metabolism, glycerophospholipid metabolism, arachidonic acid metabolism, ascorbate and aldarate metabolism and galactose metabolism. Moreover, the target metabolites and target mRNAs of AS were also enriched in five identical pathways of sphingolipid metabolism, glycerophospholipid metabolism, arachidonic acid metabolism, ascorbate and aldarate metabolism and galactose metabolism, including 8 different metabolites, such as sphingosine, and 5 different genes, such as Kng1. The 8 metabolites had high AUC prediction values, and the validation of the 5 genes was consistent with the sequencing results.

CONCLUSION

Our research showed that AS can improve DKD via the "gut-kidney axis". Akkermansia muciniphila and Lactobacillus murinus were the main driving bacteria, and five pathways related to glycolipid metabolism, especially sphingolipid metabolism and glycerophospholipid metabolism, may be important follow-up reactions and regulatory mechanisms.

Oral proprietary Chinese medicine for lupus nephritis: A bayesian network meta-analysis

Objective

To analyze the efficacy and safety of proprietary Chinese medicines for the treatment of Lupus Nephritis (LN) based on the reticulated meta analysis. The study aim to provide evidence-based evidence for the clinical treatment of LN.

Methods

The studies related to the randomized controlled studies (RCTs) on the treatment of LN with oral proprietary Chinese medicines were obtained from China National Knowledge Infrastructure (CNKI), Database for Chinese Technical Periodicals (VIP), SinoMed, Wanfang, PubMed, Web of Science, Embase and Cochrane Library databases since its inception-August 2022. Cochrane tools were used for risk bias assessment, Stata 13.0 and ADDIS 1.16.5 software were used for net evidence analysis.Results.1) 41 RCTs with 3124 L N patients were included, involving 9 types of proprietary Chinese medicines.2) The meta-analysis showed that in terms of efficacy, the top 3 Chinese patent medicine interventions were Xin Gan Bao Capsule (XGB) +western medicines (WM), Huang Kui Capsule (HK) + WM, Kun Xian Capsule (KX) + WM; in terms of reducing adverse event rate, the top 3 Chinese patent medicine interventions were Yi Shen Hua Shi Granules (YSHS) + WM, Jin Shui Bao Capsule (JSB) + WM, HK + WM; in terms of reducing 24 h urine protein, the top 3 Chinese patent medicine interventions were XGB + WM, YSHS + WM, Bai Ling Capsule (BL) + WM; in terms of reducing blood creatinine (Cr), the top 3 Chinese patent medicine interventions were Yi Shen Granules (YS) + WM, JSB + WM, KX + WM; in terms of reducing urea nitrogen (BUN), the top 3 Chinese patent medicine interventions were Shen Kang Capsule (SK) + WM, HK + WM, JSB + WM; in terms of reducing systemic lupus erythematosus disease activity index (SLEDAI) scores, the top 3 Chinese patent medicine interventions were JSB + WM, BL + WM, YSHS + WM; in terms of improving complement C3, the top 3 Chinese patent medicine interventions were HK + WM, XGB + WM, BL + WM; in terms of improving complement C4, the top 3 Chinese patent medicine interventions were KX + WM, YSHS + WM, BL + WM.

Conclusion

Xin Gan Bao Capsule has a good efficacy in improving efficiency and the level of complement C3, lowering 24 h urine protein. Jin Shui Bao Capsule and Huang Kui Capsule have a good efficacy in treating LN. However, more multicentre, large sample and high quality RCTs are needed for validation the results.

Yi-Shen-Hua-Shi granule ameliorates diabetic kidney disease by the "gut-kidney axis"

ETHNOPHARMACOLOGICAL RELEVANCE

Yi-Shen-Hua-Shi (YSHS) granule is an effective prescription widely used in traditional Chinese medicine to treat diabetic kidney disease (DKD), its exact efficacy in treating DKD has been confirmed but the underlying regulatory mechanism has not been fully elucidated.

AIM OF THE STUDY

To explore the mechanism by which YSHS granule regulates intestinal flora and serum metabolites and then regulates renal mRNA expression through the "gut-kidney axis", so as to improve DKD.

MATERIALS AND METHODS

40 rats were divided into five groups: Normal group (N) (normal saline), model group (M) (STZ + normal saline), YSHS granule low-dose group (YL) (STZ + 2.27 g kg^-1 d^-1), YSHS granule high-dose group (YH) (STZ + 5.54g kg^-1 d^-1) and valsartan group (V) (STZ + 7.38mg kg^-1 d^-1). After 6 weeks, changes in blood glucose, blood lipids, and renal function related indexes were observed, as well as pathological changes in the kidney and colon. Intestinal microbiota was sequenced by 16S rDNA, serum differential metabolites were identified by LC-MS/MS, and renal differences in mRNA expression were observed by RNA-seq. Further, through the association analysis of intestinal differential microbiota, serum differential metabolites and kidney differential mRNAs, the target flora, target metabolites and target genes of YSHS granule were screened and verified, and the "gut-metabolism-transcription" co-expression network was constructed.

RESULTS

In group M, blood glucose, blood lipid and proteinuria were increased, inflammation, oxidative stress and renal function were aggravated, with the proliferation of mesangial matrix, vacuolar degeneration of renal tubules, accumulation of collagen and lipid, and increased intestinal permeability, and YSHS granule and valsartan improved these disorders to varying degrees. High dose of YSHS granule improved the diversity and abundance of flora, decreased the F/B value, greatly increased the abundance of Lactobacillus and Lactobacillus_murinus, and decreased the abundance of Prevoella UCG_001. 14 target metabolites of YSHS granule were identified, which were mainly enriched in 20 KEGG pathways, such as Glycerophospholipid metabolism, Sphingolipid metabolism and Phenylalanine, tyrosine and tryptophan biosynthesis. 96 target mRNAs of YSHS granule were also identified. The enriched top 20 pathways were closely related to glucose and lipid metabolism, of which a total of 21 differential mRNAs were expressed. Further correlation analysis revealed that Lactobacillus, Lactobacillus_murinus and Prevotella UCG_001 were highly correlated with Glycerophospholipid metabolism, Sphingolipid metabolism and Phenylalanine, tyrosine and tryptophan biosynthesis pathways. At the same time, 6 pathways including Glycerophospholipid metabolism, Arachidonic acid metabolism, Purine metabolism, Primary bile acid biosynthesis, Ascorbate and aldarate metabolism and Galactose metabolism were co-enriched by the target metabolites and the target mRNAs of YSHS granule, including 7 differential metabolites such as phosphatidylethanolamine and 7 differential genes such as Adcy3. The 7 differential metabolites had high predictive value of AUC, and the validation of 7 differential genes were highly consistent with the sequencing results.

CONCLUSION

YSHS granule could improve DKD through the "gut-kidney axis". Lactobacillus and Lactobacillus_murinus were the main driving forces. 6 pathways related to glucose and lipid metabolism, especially Glycerophospholipid metabolism, may be an important follow-up response and regulatory mechanism.

Exploring the mechanism of action of Hedyotis diffusa Willd on acne using network analysis

In this study, we used a network pharmacological method to explore the active ingredients of Hedyotis diffusa Willd (HDW) in the treatment of acne and elucidated the physiological mechanisms in the human body in which they are involved. We identified the active compounds of HDW that are expected to act effectively in the human body using the Traditional Chinese Medicine Systems Pharmacology database and analysis platform and extracted potential interacting proteins for each active compound using the Swiss Target Prediction platform. Next, we analyzed the potential mechanisms of action of the protein targets shared by HDW and each standard drug on acne and assessed the possibility of spontaneous occurrence of the binding between proteins and active compounds through the molecular docking process. Seven active compounds were selected according to the oral bioavailability and drug-likeness criteria of the Traditional Chinese Medicine Systems Pharmacology database and analysis platform. Subsequently, 300 protein targets were collected from the Swiss Target Prediction. Using the Search Tool for the Retrieval of Interacting Genes/Proteins database, a protein-protein interaction network was constructed by analyzing the relationship between HDW, acne, and each standard drug. By analyzing the gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathway, the "positive regulation of lipid metabolic process" was found to be the most involved pathway shared by HDW, acne, and isotretinoin. An analysis of the protein targets shared by the antibiotic agents with HDW and acne found that "cholesterol storage" in tetracycline, "icosacoid transport" in azithromycin, "steroid hydroxylase activity" in erythromycin, "positive regulation of leukocyte tethering or rolling" in clindamycin, "response to UV-A" in minocycline, "steroid 11-beta-monooxygenase activity" in doxycycline, and "neutrophil-mediated immunity" in trimethoprim were the most involved. Virtual molecular docking analysis showed that all proteins spontaneously bound to their corresponding active compounds. Our analysis suggests that HDW can, directly and indirectly, suppress sebum secretion and exert antiinflammatory effects on acne. Further, HDW may regulate free radicals and suppress apoptosis. Therefore, HDW can be used as an alternative or supplement to standard drugs for acne treatment in patients who cannot use standard treatments due to side effects.

Fatty acids negatively regulate platelet function through formation of noncanonical 15-lipoxygenase-derived eicosanoids

The antiplatelet effect of polyunsaturated fatty acids is primarily attributed to its metabolism to bioactive metabolites by oxygenases, such as lipoxygenases (LOX). Platelets have demonstrated the ability to generate 15-LOX-derived metabolites (15-oxylipins); however, whether 15-LOX is in the platelet or is required for the formation of 15-oxylipins remains unclear. This study seeks to elucidate whether 15-LOX is required for the formation of 15-oxylipins in the platelet and determine their mechanistic effects on platelet reactivity. In this study, 15-HETrE, 15-HETE, and 15-HEPE attenuated collagen-induced platelet aggregation, and 15-HETrE inhibited platelet aggregation induced by different agonists. The observed anti-aggregatory effect was due to the inhibition of intracellular signaling including αIIbβ3 and protein kinase C activities, calcium mobilization, and granule secretion. While 15-HETrE inhibited platelets partially through activation of peroxisome proliferator-activated receptor β (PPARβ), 15-HETE also inhibited platelets partially through activation of PPARα. 15-HETrE, 15-HETE, or 15-HEPE inhibited 12-LOX in vitro, with arachidonic acid as the substrate. Additionally, a 15-oxylipin-dependent attenuation of 12-HETE level was observed in platelets following ex vivo treatment with 15-HETrE, 15-HETE, or 15-HEPE. Platelets treated with DGLA formed 15-HETrE and collagen-induced platelet aggregation was attenuated only in the presence of ML355 or aspirin, but not in the presence of 15-LOX-1 or 15-LOX-2 inhibitors. Expression of 15-LOX-1, but not 15-LOX-2, was decreased in leukocyte-depleted platelets compared to non-depleted platelets. Taken together, these findings suggest that 15-oxylipins regulate platelet reactivity; however, platelet expression of 15-LOX-1 is low, suggesting that 15-oxylipins may be formed in the platelet through a 15-LOX-independent pathway.

Detoxification Cytochrome P450s (CYPs) in Families 1-3 Produce Functional Oxylipins from Polyunsaturated Fatty Acids

This manuscript reviews the CYP-mediated production of oxylipins and the current known function of these diverse set of oxylipins with emphasis on the detoxification CYPs in families 1-3. Our knowledge of oxylipin function has greatly increased over the past 3-7 years with new theories on stability and function. This includes a significant amount of new information on oxylipins produced from linoleic acid (LA) and the omega-3 PUFA-derived oxylipins such as α-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). However, there is still a lack of knowledge regarding the primary CYP responsible for producing specific oxylipins, and a lack of mechanistic insight for some clinical associations between outcomes and oxylipin levels. In addition, the role of CYPs in the production of oxylipins as signaling molecules for obesity, energy utilization, and development have increased greatly with potential interactions between diet, endocrinology, and pharmacology/toxicology due to nuclear receptor mediated CYP induction, CYP inhibition, and receptor interactions/crosstalk. The potential for diet-diet and diet-drug/chemical interactions is high given that these promiscuous CYPs metabolize a plethora of different endogenous and exogenous chemicals.

Pseudomonas aeruginosa cytochrome P450 CYP168A1 is a fatty acid hydroxylase that metabolizes arachidonic acid to the vasodilator 19-HETE

Pseudomonas aeruginosa is a Gram-negative opportunistic human pathogen that is highly prevalent in individuals with cystic fibrosis (CF). A major problem in treating CF patients infected with P. aeruginosa is the development of antibiotic resistance. Therefore, the identification of novel P. aeruginosa antibiotic drug targets is of the utmost urgency. The genome of P. aeruginosa contains four putative cytochrome P450 enzymes (CYPs) of unknown function that have never before been characterized. Analogous to some of the CYPs from Mycobacterium tuberculosis, these P. aeruginosa CYPs may be important for growth and colonization of CF patients’ lungs. In this study, we cloned, expressed, and characterized CYP168A1 from P. aeruginosa and identified it as a subterminal fatty acid hydroxylase. Spectral binding data and computational modeling of substrates and inhibitors suggest that CYP168A1 has a large, expansive active site and preferentially binds long chain fatty acids and large hydrophobic inhibitors. Furthermore, metabolic experiments confirm that the enzyme is capable of hydroxylating arachidonic acid, an important inflammatory signaling molecule present in abundance in the CF lung, to 19-hydroxyeicosatetraenoic acid (19-HETE; K_m = 41 μM, V_max = 220 pmol/min/nmol P450), a potent vasodilator, which may play a role in the pathogen’s ability to colonize the lung. Additionally, we found that the in vitro metabolism of arachidonic acid is subject to substrate inhibition and is also inhibited by the presence of the antifungal agent ketoconazole. This study identifies a new metabolic pathway in this important human pathogen that may be of utility in treating P. aeruginosa infections.

Modified Xiaoqinglong decoction alleviates lipopolysaccharide-induced acute lung injury in mice by regulating arachidonic acid metabolism and exerting anti-apoptotic and anti-inflammatory effects

Effective therapeutics are not available for acute lung injury (ALI) and acute respiratory distress syndrome. Modified Xiaoqinglong decoction (M-XQL) is reported to effectively treat pneumonia, but the underlying mechanisms are unclear. In this study, the therapeutic effect and mechanism of M-XQL were examined using a lipopolysaccharide (LPS)-induced ALI mouse model. The effects of M-XQL on lung injury, inflammatory responses, and cell apoptosis were analyzed. Additionally, high-throughput sequencing was performed to evaluate the therapeutic mechanism of M-XQL. Pretreatment with M-XQL significantly and dose-dependently mitigated the pathological changes and upregulation of pulmonary, nitric oxide content and cell apoptosis and serum tumor necrosis factor-alpha contents in the LPS-induced ALI mouse model. RNA sequencing analysis revealed that the expression of several arachidonic acid metabolism-associated genes in the LPS + high-dose M-XQL group differed from that in the LPS group. In particular, the Cbr2, Cyp4f18, and Cyp2e1 levels were upregulated, whereas the Alox12, Ptges, and Ptges2 levels were downregulated in the LPS + high-dose M-XQL group. These results suggest that M-XQL exerts therapeutic effects in ALI mice by regulating arachidonic acid metabolism and exerting anti-apoptotic and anti-inflammatory effects. Thus, M-XQL is a potential agent for the clinical treatment of ALI.

A review of non-prostanoid, eicosanoid receptors: expression, characterization, regulation, and mechanism of action

Eicosanoid signaling controls a wide range of biological processes from blood pressure homeostasis to inflammation and resolution thereof to the perception of pain and to cell survival itself. Disruption of normal eicosanoid signaling is implicated in numerous disease states. Eicosanoid signaling is facilitated by G-protein-coupled, eicosanoid-specific receptors and the array of associated G-proteins. This review focuses on the expression, characterization, regulation, and mechanism of action of non-prostanoid, eicosanoid receptors.

Genomics of Adaptations in Ungulates

Ungulates are a group of hoofed animals that have long interacted with humans as essential sources of food, labor, clothing, and transportation. These consist of domesticated, feral, and wild species raised in a wide range of habitats and biomes. Given the diverse and extreme environments inhabited by ungulates, unique adaptive traits are fundamental for fitness. The documentation of genes that underlie their genomic signatures of selection is crucial in this regard. The increasing availability of advanced sequencing technologies has seen the rapid growth of ungulate genomic resources, which offers an exceptional opportunity to understand their adaptive evolution. Here, we summarize the current knowledge on evolutionary genetic signatures underlying the adaptations of ungulates to different habitats.

CYP2J2 Molecular Recognition: A New Axis for Therapeutic Design

Cytochrome P450 (CYP) epoxygenases are a special subset of heme-containing CYP enzymes capable of performing the epoxidation of polyunsaturated fatty acids (PUFA) and the metabolism of xenobiotics. This dual functionality positions epoxygenases along a metabolic crossroad. Therefore, structure-function studies are critical for understanding their role in bioactive oxy-lipid synthesis, drug-PUFA interactions, and for designing therapeutics that directly target the epoxygenases. To better exploit CYP epoxygenases as therapeutic targets, there is a need for improved understanding of epoxygenase structure-function. Of the characterized epoxygenases, human CYP2J2 stands out as a potential target because of its role in cardiovascular physiology. In this review, the early research on the discovery and activity of epoxygenases is contextualized to more recent advances in CYP epoxygenase enzymology with respect to PUFA and drug metabolism. Additionally, this review employs CYP2J2 epoxygenase as a model system to highlight both the seminal works and recent advances in epoxygenase enzymology. Herein we cover CYP2J2's interactions with PUFAs and xenobiotics, its tissue-specific physiological roles in diseased states, and its structural features that enable epoxygenase function. Additionally, the enumeration of research on CYP2J2 identifies the future needs for the molecular characterization of CYP2J2 to enable a new axis of therapeutic design.

A Review of Prostanoid Receptors: Expression, Characterization, Regulation, and Mechanism of Action

Prostaglandin signaling controls a wide range of biological processes from blood pressure homeostasis to inflammation and resolution thereof to the perception of pain to cell survival. Disruption of normal prostanoid signaling is implicated in numerous disease states. Prostaglandin signaling is facilitated by G-protein-coupled, prostanoid-specific receptors and the array of associated G-proteins. This review focuses on the expression, characterization, regulation, and mechanism of action of prostanoid receptors with particular emphasis on human isoforms.

Bioactive Lipid Signaling in Cardiovascular Disease, Development, and Regeneration

Cardiovascular disease (CVD) remains a leading cause of death globally. Understanding and characterizing the biochemical context of the cardiovascular system in health and disease is a necessary preliminary step for developing novel therapeutic strategies aimed at restoring cardiovascular function. Bioactive lipids are a class of dietary-dependent, chemically heterogeneous lipids with potent biological signaling functions. They have been intensively studied for their roles in immunity, inflammation, and reproduction, among others. Recent advances in liquid chromatography-mass spectrometry techniques have revealed a staggering number of novel bioactive lipids, most of them unknown or very poorly characterized in a biological context. Some of these new bioactive lipids play important roles in cardiovascular biology, including development, inflammation, regeneration, stem cell differentiation, and regulation of cell proliferation. Identifying the lipid signaling pathways underlying these effects and uncovering their novel biological functions could pave the way for new therapeutic strategies aimed at CVD and cardiovascular regeneration.

Protective Effect of Ocotillol, the Derivate of Ocotillol-Type Saponins in Panax Genus, against Acetic Acid-Induced Gastric Ulcer in Rats Based on Untargeted Metabolomics

Gastric ulcer (GU), a prevalent digestive disease, has a high incidence and is seriously harmful to human health. Finding a natural drug with a gastroprotective effect is needed. Ocotillol, the derivate of ocotillol-type saponins in the Panax genus, possesses good anti-inflammatory activity. The study aimed to investigate the gastroprotective effect of ocotillol on acetic acid-induced GU rats. The serum levels of endothelin-1 (ET-1) and nitric oxide (NO), the gastric mucosa levels of epidermal growth factor, superoxide dismutase and NO were assessed. Hematoxylin and eosin staining of gastric mucosa for pathological changes and immunohistochemical staining of ET-1, epidermal growth factor receptors and inducible nitric oxide synthase were evaluated. A UPLC-QTOF-MS-based serum metabolomics approach was applied to explore the latent mechanism. A total of 21 potential metabolites involved in 7 metabolic pathways were identified. The study helps us to understand the pathogenesis of GU and to provide a potential natural anti-ulcer agent.

P450 Eicosanoids and Reactive Oxygen Species Interplay in Brain Injury and Neuroprotection

Significance: Eicosanoids are endogenous lipid mediators that play important roles in brain function and disease. Acute brain injury such as that which occurs in stroke and traumatic brain injury increases the formation of eicosanoids, which, in turn, exacerbate or diminish injury. In chronic neurodegenerative diseases such as Alzheimer's disease and vascular dementia (VD), eicosanoid synthetic and metabolizing enzymes are altered, disrupting the balance between neuroprotective and neurotoxic eicosanoids. Recent Advances: Human and experimental studies have established the opposing roles of hydroxy- and epoxyeicosanoids and their potential utility as diagnostic biomarkers and therapeutic targets in neural injury. Critical Issues: A gap in knowledge remains in understanding the cellular and molecular mechanisms underlying the neurovascular actions of specific eicosanoids, such as specific isomers of epoxyeicosatrienoic (EETs) and hydroxyeicosatetraenoic acids (HETEs). Future Directions: EETs and HETEs exert their actions on brain cells by targeting multiple mechanisms, which include surface G-protein coupled receptors. The identification of high-affinity receptors for EETs and HETEs and their cellular localization in the brain will be a breakthrough in our understanding of these eicosanoids as mediators of cell-cell communications and contributors to brain development, function, and disease. Antioxid. Redox Signal. 28, 987-1007.

Dietary restriction but not angiotensin II type 1 receptor blockade improves DNA damage-related vasodilator dysfunction in rapidly aging Ercc1Δ/− mice

DNA damage is an important contributor to endothelial dysfunction and age-related vascular disease. Recently, we demonstrated in a DNA repair-deficient, prematurely aging mouse model (Ercc1Δ/− mice) that dietary restriction (DR) strongly increases life- and health span, including ameliorating endothelial dysfunction, by preserving genomic integrity. In this mouse mutant displaying prominent accelerated, age-dependent endothelial dysfunction we investigated the signaling pathways involved in improved endothelium-mediated vasodilation by DR, and explore the potential role of the renin-angiotensin system (RAS). Ercc1Δ/− mice showed increased blood pressure and decreased aortic relaxations to acetylcholine (ACh) in organ bath experiments. Nitric oxide (NO) signaling and phospho-Ser1177-eNOS were compromised in Ercc1Δ/−. DR improved relaxations by increasing prostaglandin-mediated responses. Increase of cyclo-oxygenase 2 and decrease of phosphodiesterase 4B were identified as potential mechanisms. DR also prevented loss of NO signaling in vascular smooth muscle cells and normalized angiotensin II (Ang II) vasoconstrictions, which were increased in Ercc1Δ/− mice. Ercc1Δ/− mutants showed a loss of Ang II type 2 receptor-mediated counter-regulation of Ang II type 1 receptor-induced vasoconstrictions. Chronic losartan treatment effectively decreased blood pressure, but did not improve endothelium-dependent relaxations. This result might relate to the aging-associated loss of treatment efficacy of RAS blockade with respect to endothelial function improvement. In summary, DR effectively prevents endothelium-dependent vasodilator dysfunction by augmenting prostaglandin-mediated responses, whereas chronic Ang II type 1 receptor blockade is ineffective.

The expansive role of oxylipins on platelet biology

In mammals, three major oxygenases, cyclooxygenases (COXs), lipoxygenases (LOXs), and cytochrome P450 (CYP450), generate an assortment of unique lipid mediators (oxylipins) from polyunsaturated fatty acids (PUFAs) which exhibit pro- or anti-thrombotic activity. Over the years, novel oxylipins generated from the interplay of theoxygenase activity in various cells, such as the specialized pro-resolving mediators (SPMs), have been identified and investigated in inflammatory disease models. Although platelets have been implicated in inflammation, the role and mechanism of these SPMs produced from immune cells on platelet function are still unclear. This review highlights the burgeoning classes of oxylipins that have been found to regulate platelet function; however, their mechanism of action still remains to be elucidated.