5-Lipoxygenase: mechanisms of regulation

Shexiang Tongxin dropping pill ameliorates microvascular obstruction via downregulating ALOX12 after myocardial ischemia-reperfusion

BACKGROUND

Microvascular dysfunction (MVD) is common in patients with myocardial infarction receiving reperfusion therapy and is associated with adverse cardiac prognosis. Accumulating evidence suggests a protective role of Shexiang Tongxin dropping pill (STDP) in MVD. However, the specific effects and the underlying mechanisms of STDP in the context of MVD after myocardial ischemia-reperfusion (IR) remains unclear.

AIMS

We aimed to elucidate the role of STDP in MVD induced by IR and the potential mechanisms involved.

METHODS

Mice were orally administered with STDP or normal saline for 5 days before receiving myocardial IR. Cardiac function and microvascular obstruction was measured. Proteomics and single-cell RNA sequencing was performed on mouse hearts. In vitro hyoxia/reoxygenation model was established on mouse cardiac microvascular endothelial cells (MCMECs).

RESULTS

STDP improved cardiac function and decreased microvascular obstruction (MVO) in mice after myocardial IR. Proteomics identified ALOX12 as an important target of STDP. Single-cell RNA sequencing further revealed that downregulation of ALOX12 by STDP mainly occurred in endothelial cells. The involvement of ALOX12 in the effect of STDP on MVO was validated by manipulating ALOX12 via endothelial-specific adeno-associated virus transfection in vivo and in vitro. In vivo, overexpression of ALOX12 increased whereas knockdown of ALOX12 decreased MVO and thrombus formation. STDP treatment alleviated the detrimental effects of overexpression of ALOX12. In vitro, overexpression of ALOX12 increased endothelial cell inflammation and platelet adhesion to endothelial cells, which was abolished by STDP treatment.

CONCLUSION

Our findings suggest that STDP alleviates MVO after IR, with ALOX12 playing a crucial role.

Systematic analysis based on bioinformatics and experimental validation identifies Alox5 as a novel therapeutic target of quercetin for sepsis

PURPOSE

This study investigated the molecular mechanism of quercetin in the treatment of sepsis using network pharmacological prediction and experimentation.

METHODS

Hub genes were identified by intersecting the differentially expressed genes (DEGs) of the GSE131761 and GSE9960 databases with genes from the hub modules of Weighted Gene Co-Expression Network Analysis (WGCNA), targets of quercetin, and ferroptosis. Subsequently, in order to determine the functional characteristics and molecular link of hub gene obtained above, we redetermined the hub-DEGs in GSE131761 according to high or low hub gene expression. Afterward, the main pathways of enrichment analysis were validated using these hub-DEGs. Finally, an experiment was conducted to validate the findings.

RESULTS

By intersecting 1415 DEGs in GSE131761, 543 DEGs in GSE9960, 5784 key modular genes, 470 ferroptosis-related genes, and 154 quercetin-related genes, we obtained one quercetin-related gene, Alox5. Subsequently, 340 hub-DEGs were further validated according to high or low Alox5 expression. The results of the enrichment analysis revealed that hub-DEGs were mainly associated with inflammation and the immune response. Immune infiltration analysis showed that higher expression of Alox5 was related to macrophage infiltration and could be a predictor of diagnosis in patients with sepsis. The expression pattern of Alox5 was then depicted and the upregulation of Alox5 in the vital organs of septic mice was further demonstrated. In vitro and in vivo experiments showed that upregulation of Alox5 and inflammation-related cytokines induced by sepsis could be inhibited by quercetin (p < 0.05).

CONCLUSIONS

Alox5 may be involved in the occurrence and development of multi-organ functional disturbances in sepsis and is a reliable target of quercetin against sepsis.

Vitis vinifera Lipoxygenase LoxA is an Allosteric Dimer Activated by Lipidic Surfaces

Lipoxygenases catalyze the peroxidation of poly-unsaturated fatty acid chains either free or esterified in membrane lipids. Vitis vinifera LoxA is transcriptionally induced at ripening onset and localizes at the inner chloroplast membrane where it is responsible for galactolipid regiospecific mono- and di-peroxidation. Here we present a kinetic and structural characterization of LoxA. Our X-ray structures reveal a constitutive dimer with detergent induced conformational changes affecting substrate binding and catalysis. In a closed conformation, a LID domain prevents substrate access to the catalytic site by steric hindrance. Detergent addition above the CMC destabilizes the LID and opens the dimer with both catalytic sites accessible from the same surface framed by the PLAT domains. As a consequence, detergent molecules occupy allosteric sites in the PLAT/catalytic domain interface. These structural changes are mirrored by increased enzymatic activity and positive cooperativity when the substrate is provided in micelles. The ability to interact with micelles is lost upon dimer destabilization by site-directed mutagenesis as assessed by tryptophan fluorescence. Our data allow to propose a model for protein activation at the membrane, classifying LoxA as an interfacial enzyme acting on fatty acid chains directly from the membrane similar to mammalian 15-LOX and 5-LOX.

Phospholipids, Sphingolipids, and Cholesterol-Derived Lipid Mediators and Their Role in Neurological Disorders

Neural membranes are composed of phospholipids, sphingolipids, cholesterol, and proteins. In response to cell stimulation or injury, the metabolism of lipids generates various lipid mediators, which perform many cellular functions. Thus, phospholipids release arachidonic acid or docosahexaenoic acid from the sn-2 position of the glycerol moiety by the action of phospholipases A2. Arachidonic acid is a precursor for prostaglandins, leukotrienes, thromboxane, and lipoxins. Among these mediators, prostaglandins, leukotrienes, and thromboxane produce neuroinflammation. In contrast, lipoxins produce anti-inflammatory and pro-resolving effects. Prostaglandins, leukotrienes, and thromboxane are also involved in cell proliferation, differentiation, blood clotting, and blood vessel permeability. In contrast, DHA-derived lipid mediators are called specialized pro-resolving lipid metabolites (SPMs). They include resolvins, protectins, and maresins. These mediators regulate immune function by producing anti-inflammatory, pro-resolving, and cell protective effects. Sphingolipid-derived metabolites are ceramide, ceramide1-phosphate, sphingosine, and sphingosine 1 phosphate. They regulate many cellular processes, including enzyme activities, cell migration and adhesion, inflammation, and immunity. Cholesterol is metabolized into hydroxycholesterols and 7-ketocholesterol, which not only disrupts membrane fluidity, but also promotes inflammation, oxidative stress, and apoptosis. These processes lead to cellular damage.

Distinct mechanisms of type 3 secretion system recognition control LTB4 synthesis in neutrophils and macrophages

Leukotriene B4 (LTB4) is an inflammatory lipid produced in response to pathogens that is critical for initiating the inflammatory cascade needed to control infection. However, during plague, Yersinia pestis inhibits the timely synthesis of LTB4 and subsequent inflammation. Using bacterial mutants, we previously determined that Y. pestis inhibits LTB4 synthesis via the action of the Yop effector proteins that are directly secreted into host cells through a type 3 secretion system (T3SS). Here, we show that the T3SS is the primary pathogen associated molecular pattern (PAMP) required for production of LTB4 in response to both Yersinia and Salmonella. However, we also unexpectantly discovered that T3SS-mediated LTB4 synthesis by neutrophils and macrophages require the activation of two distinctly different host signaling pathways. We identified that phagocytosis and the NLRP3/CASP1 inflammasome significantly impact LTB4 synthesis by macrophages but not neutrophils. Instead, the SKAP2/PLC signaling pathway is required for T3SS-mediated LTB4 production by neutrophils. Finally, while recognition of the T3SS is required for LTB4 production, we also discovered that a second unrelated PAMP-mediated signal activates the MAP kinase pathway needed for synthesis. Together, these data demonstrate significant differences in the host factors and signaling pathways required by macrophages and neutrophils to quickly produce LTB4 in response to bacteria. Moreover, while macrophages and neutrophils might rely on different signaling pathways for T3SS-dependent LTB4 synthesis, Y. pestis has evolved virulence mechanisms to counteract this response by either leukocyte to inhibit LTB4 synthesis and colonize the host.

Real time changes in the expression of eicosanoid synthesizing enzymes during inflammation

Immune responses during inflammation involve complex, well-coordinated lipid signaling pathways. Eicosanoids are a class of lipid signaling molecules derived from polyunsaturated fatty acids such as arachidonic acid and constitute a major network that controls inflammation and its subsequent resolution. Arachidonic acid is metabolized by enzymes in three different pathways to form a variety of lipid metabolites that can be either pro- or anti-inflammatory. Therefore, an understanding of the time-dependent gene expression, lipid metabolite profiles and cytokine profiles during the initial inflammatory response is necessary, as it will allow for the design of time-dependent therapeutics. Herein, we investigate the multi-level regulation of this process. After stimulating RAW 264.7 cells, a mouse-derived macrophage cell line commonly used to examine inflammatory responses, we examine the gene expression of 44 relevant lipid metabolizing enzymes from the different eicosanoid synthesizing classes. We also measure the formation of lipid metabolites and production of cytokines at selected time points. Results reveal a dynamic relationship between the time-course of inflammation dependent gene expression of the three eicosanoid synthesizing enzymes.

NADPH oxidase-dependent free radical generation and protein adduct formation in neutrophils

Neutrophils mediate the early innate immune response through extracellular traps comprising intracellular protein and DNA. These traps play a pivotal role in both immunity against invading pathogens and the development of immunopathological reactions through the production of reactive oxygen species (ROS). Proteins serve as the main target for ROS, resulting in the formation of protein adducts. Herein, we report that the superoxide anion radical (O2˙-) plays a vital role in neutrophil function through sequential events involving 5-lipoxygenase (5-LOX) and NADPH oxidase (NOX). More specifically, differences in NOX homologs expression were observed post-stimulation with PMA and LPS. Differentiation conditions and O2˙- generation were confirmed using flow cytometry. Immunoblotting analysis confirmed the time-dependent expression of NOX underlying its requirement and 5-LOX-mediated lipid peroxidation events in neutrophil function. Protein-malondialdehyde (MDA) adducts formed were detected using immunoblotting, and quercetin was evaluated for its ability to scavenge free radicals through electron paramagnetic resonance (EPR) spin-trapping spectroscopy and results were confirmed with blotting analysis. Free radical-mediated protein oxidation events influence neutrophil function and protein adducts formed serve as markers of neutrophil activation upon infection and inflammation. The study warrants further corroboration and the study of specific proteins involved in neutrophil activation and their role in inflammation.

Distinct Mechanisms of Type 3 Secretion System Recognition Control LTB4 Synthesis in Neutrophils versus Macrophages

Leukotriene B4 (LTB4) is critical for initiating the inflammatory cascade in response to infection. However, Yersinia pestis colonizes the host by inhibiting the timely synthesis of LTB4 and inflammation. Here, we show that the bacterial type 3 secretion system (T3SS) is the primary pathogen associated molecular pattern (PAMP) responsible for LTB4 production by leukocytes in response to Yersinia and Salmonella, but synthesis is inhibited by the Yop effectors during Yersinia interactions. Moreover, we unexpectedly discovered that T3SS-mediated LTB4 synthesis by neutrophils and macrophages require two distinct host signaling pathways. We show that the SKAP2/PLC signaling pathway is essential for LTB4 production by neutrophils but not macrophages. Instead, phagocytosis and the NLRP3/CASP1 inflammasome are needed for LTB4 synthesis by macrophages. Finally, while recognition of the T3SS is required for LTB4 production, we also discovered a second unrelated PAMP-mediated signal independently activates the MAP kinase pathway needed for LTB4 synthesis. Together, these data demonstrate significant differences in the signaling pathways required by macrophages and neutrophils to quickly respond to bacterial infections.

Excessive linoleic acid induces muscle oxidative stress through 5-lipoxygenase-dependent peroxidation

Oxidative stress in muscles is closely related to the occurrence of insulin resistance, muscle weakness and atrophy, age-related sarcopenia, and cancer. Aldehydes, a primary oxidation intermediate of polyunsaturated fatty acids, have been proven to be an important trigger for oxidative stress. However, the potential role of linoleic acid (LA) as a donor for volatile aldehydes to trigger oxidative stress has not been reported. Here, we reported that excessive dietary LA caused muscle redox imbalance and volatile aldehydes containing hexanal, 2-hexenal, and nonanal were the main metabolites leading to oxidative stress. Importantly, we identified 5-lipoxygenase (5-LOX) as a key enzyme mediating LA peroxidation in crustaceans for the first time. The inhibition of 5-LOX significantly suppressed the content of aldehydes produced by excessive LA. Mechanistically, the activation of the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway facilitated the translocation of 5-LOX from the nucleus to the cytoplasm, where 5-LOX oxidized LA, leading to oxidative stress through the generation of aldehydes. This study suggests that 5-LOX is a potential target to prevent the production of harmful aldehydes.

Climate-Affected Australian Tropical Montane Cloud Forest Plants: Metabolomic Profiles, Isolated Phytochemicals, and Bioactivities

The Australian Wet Tropics World Heritage Area (WTWHA) in northeast Queensland is home to approximately 18 percent of the nation's total vascular plant species. Over the past century, human activity and industrial development have caused global climate changes, posing a severe and irreversible danger to the entire land-based ecosystem, and the WTWHA is no exception. The current average annual temperature of WTWHA in northeast Queensland is 24 °C. However, in the coming years (by 2030), the average annual temperature increase is estimated to be between 0.5 and 1.4 °C compared to the climate observed between 1986 and 2005. Looking further ahead to 2070, the anticipated temperature rise is projected to be between 1.0 and 3.2 °C, with the exact range depending on future emissions. We identified 84 plant species, endemic to tropical montane cloud forests (TMCF) within the WTWHA, which are already experiencing climate change threats. Some of these plants are used in herbal medicines. This study comprehensively reviewed the metabolomics studies conducted on these 84 plant species until now toward understanding their physiological and metabolomics responses to global climate change. This review also discusses the following: (i) recent developments in plant metabolomics studies that can be applied to study and better understand the interactions of wet tropics plants with climatic stress, (ii) medicinal plants and isolated phytochemicals with structural diversity, and (iii) reported biological activities of crude extracts and isolated compounds.

Novel lipid mediator 7S,14R-docosahexaenoic acid: biogenesis and harnessing mesenchymal stem cells to ameliorate diabetic mellitus and retinal pericyte loss

Introduction: Stem cells can be used to treat diabetic mellitus and complications. ω3-docosahexaenoic acid (DHA) derived lipid mediators are inflammation-resolving and protective. This study found novel DHA-derived 7S,14R-dihydroxy-4Z,8E,10Z,12E,16Z,19Z-docosahexaenoic acid (7S,14R-diHDHA), a maresin-1 stereoisomer biosynthesized by leukocytes and related enzymes. Moreover, 7S,14R-diHDHA can enhance mesenchymal stem cell (MSC) functions in the amelioration of diabetic mellitus and retinal pericyte loss in diabetic db/db mice. Methods: MSCs treated with 7S,14R-diHDHA were delivered into db/db mice i.v. every 5 days for 35 days. Results: Blood glucose levels in diabetic mice were lowered by 7S,14R-diHDHA-treated MSCs compared to control and untreated MSC groups, accompanied by improved glucose tolerance and higher blood insulin levels. 7S,14R-diHDHA-treated MSCs increased insulin+ β-cell ratio and decreased glucogan+ α-cell ratio in islets, as well as reduced macrophages in pancreas. 7S,14R-diHDHA induced MSC functions in promoting MIN6 β-cell viability and insulin secretion. 7S,14R-diHDHA induced MSC paracrine functions by increasing the generation of hepatocyte growth factor and vascular endothelial growth factor. Furthermore, 7S,14R-diHDHA enhanced MSC functions to ameliorate diabetes-caused pericyte loss in diabetic retinopathy by increasing their density in retina in db/db mice. Discussion: Our findings provide a novel strategy for improving therapy for diabetes and diabetic retinopathy using 7S,14R-diHDHA-primed MSCs.

Type 3 secretion system induced leukotriene B4 synthesis by leukocytes is actively inhibited by Yersinia pestis to evade early immune recognition

Subverting the host immune response to inhibit inflammation is a key virulence strategy of Yersinia pestis. The inflammatory cascade is tightly controlled via the sequential action of lipid and protein mediators of inflammation. Because delayed inflammation is essential for Y. pestis to cause lethal infection, defining the Y. pestis mechanisms to manipulate the inflammatory cascade is necessary to understand this pathogen's virulence. While previous studies have established that Y. pestis actively inhibits the expression of host proteins that mediate inflammation, there is currently a gap in our understanding of the inflammatory lipid mediator response during plague. Here we used the murine model to define the kinetics of the synthesis of leukotriene B4 (LTB4), a pro-inflammatory lipid chemoattractant and immune cell activator, within the lungs during pneumonic plague. Furthermore, we demonstrated that exogenous administration of LTB4 prior to infection limited bacterial proliferation, suggesting that the absence of LTB4 synthesis during plague contributes to Y. pestis immune evasion. Using primary leukocytes from mice and humans further revealed that Y. pestis actively inhibits the synthesis of LTB4. Finally, using Y. pestis mutants in the Ysc type 3 secretion system (T3SS) and Yersinia outer protein (Yop) effectors, we demonstrate that leukocytes recognize the T3SS to initiate the rapid synthesis of LTB4. However, several Yop effectors secreted through the T3SS effectively inhibit this host response. Together, these data demonstrate that Y. pestis actively inhibits the synthesis of the inflammatory lipid LTB4 contributing to the delay in the inflammatory cascade required for rapid recruitment of leukocytes to sites of infection.

Human cytomegalovirus infection enhances 5‑lipoxygenase and cycloxygenase‑2 expression in colorectal cancer

Colorectal cancer (CRC) is one of the most common and fatal types of cancer. Inflammation promotes CRC development, however, the underlying etiological factors are unknown. Human cytomegalovirus (HCMV), a virus that induces inflammation and other cancer hallmarks, has been detected in several types of malignancy, including CRC. The present study investigated whether HCMV infection was associated with expression of the pro‑inflammatory enzymes 5‑lipoxygenase (5‑LO) and cyclooxygenase‑2 (COX‑2) and other molecular, genetic and clinicopathological CRC features. The present study assessed 146 individual paraffin‑embedded CRC tissue microarray (TMA) cores already characterized for TP53 and KRAS mutations, microsatellite instability (MSI) status, Ki‑67 index and EGFR by immunohistochemistry (IHC). The cores were further analyzed by IHC for the expression of two HCMV proteins (Immediate Early, IE and pp65) and the inflammatory markers 5‑LO and COX‑2. The CRC cell lines Caco‑2 and LS‑174T were infected with HCMV strain VR1814, treated with antiviral drug ganciclovir (GCV) and/or anti‑inflammatory drug celecoxib (CCX) and analyzed by reverse transcription‑quantitative PCR and immunofluorescence for 5‑LO, COX‑2, IE and pp65 transcripts and proteins. HCMV IE and pp65 proteins were detected in ~90% of the CRC cases tested; this was correlated with COX‑2, 5‑LO and KI‑67 expression, but not with EGFR immunostaining, TP53 and KRAS mutations or MSI status. In vitro, HCMV infection upregulated 5‑LO and COX‑2 transcript and proteins in both Caco‑2 and LS‑174T cells and enhanced cell proliferation as determined by MTT assay. Treatment with GCV and CCX significantly decreased the transcript levels of COX‑2, 5‑LO, HCMV IE and pp65 in infected cells. HCMV was widely expressed in CRC and may promote inflammation and serve as a potential new target for CRC therapy.

In Vitro Evaluation and In Silico Calculations of the Antioxidant and Anti-Inflammatory Properties of Secondary Metabolites from Leonurus sibiricus L. Root Extracts

Leonurus sibiricus L. has great ethnobotanical and ethnomedicinal significance. This study aimed to assess the antioxidant and anti-inflammatory properties of Leonurus sibiricus L. transgenic roots extracts transformed by Rhizobium rhizogenes, with and without the AtPAP1 transcriptional factor. The study determined the total phenolic and flavonoid contents, as well as in vitro antioxidant assays, including hydrogen peroxide and nitric oxide scavenging activity. In addition, in silico computational studies and molecular docking were conducted to evaluate the antioxidant and anti-inflammatory potential of the identified compounds. The ligands were docked to NADPH oxidase, cyclooxygenase 2,5-lipoxygenase, inducible nitric synthase and xanthine oxidase: enzymes involved in the inflammatory process. The total phenolic and flavonoid contents ranged from 85.3 ± 0.35 to 57.4 ± 0.15 mg/g GAE/g and 25.6 ± 0.42 to 18.2 ± 0.44 mg/g QUE/g in hairy root extracts with and without AtPAP1, respectively. H2O2 scavenging activity (IC50) was found to be 29.3 µg/mL (with AtPAP1) and 37.5 µg/mL (without AtPAP1 transcriptional factor), and NO scavenging activity (IC50) was 48.0 µg/mL (with AtPAP1) and 68.8 µg/mL (without AtPAP1 transcriptional factor). Leonurus sibiricus L. transformed root extracts, both with and without AtPAP1, are a source of phytochemicals belonging to different classes of molecules, such as flavonoids (catechin and rutin), phenolic compounds (caffeic acid, coumaric acid, chlorogenic acid, ferulic acid) and phenylpropanoid (verbascoside). Among the radicals formed after H removal from the different -OH positions, the lowest bond dissociation enthalpy was observed for rutin (4'-OH). Rutin was found to bind with cyclooxygenase 2, inducible nitric synthases and xanthine oxidase, whereas chlorogenic acid demonstrated optimal binding with 5-lipoxygenase. Therefore, it appears that the Leonurus sibiricus L. transformed root extract, both with and without the AtPAP1 transcriptional factor, may serve as a potential source of active components with antioxidant and anti-inflammatory potential; however, the extract containing AtPAP1 demonstrates superior activities. These properties could be beneficial for human health.

Production profile of lipid mediators in conjunctival lavage fluid in allergic and infectious conjunctivitis in guinea pigs

Introduction

Conjunctivitis is a major ocular disease classified into allergic or infectious. The pathological features of conjunctivitis are not fully understood despite its high morbidity rate; thus, its differentiation can be difficult.

Materials and methods

We used ovalbumin-induced allergic conjunctivitis and lipopolysaccharide-induced infectious conjunctivitis models of guinea pigs. Both models showed conjunctival swelling. Histological studies revealed that numerous eosinophils infiltrated the conjunctiva in the allergic model, whereas neutrophils infiltrated the conjunctiva in the infectious model. We collected conjunctival lavage fluid (COLF) and comprehensively analyzed lipid production using liquid chromatography-tandem mass spectrometry.

Results

COLF showed increase of 20 and 12 lipid species levels in the allergic and infectious models, respectively. Specifically, the levels of a major allergic mediator, prostaglandin D₂ and its three metabolites and several cytochrome P450-catalyzed lipids increased in the allergic model. In the infectious model, the levels of prostaglandin E₂ and 8-iso-prostaglandin E₂ increased, indicating tissue inflammation. Moreover, the level of 12-oxo-eicosatetraenoic acid, a lipoxygenase metabolite, increased in the infectious model.

Conclusion

These differences in lipid production in the COLF reflected the pathological features of allergic and infectious conjunctivitis.

Potential role of lnc-METRNL-1 in the occurrence and prognosis of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumors of the head and neck with poor prognosis. This study aimed to explore the role of lnc-METRNL-1 in occurrence and prognosis of OSCC patients. Expression of lnc-METRNL-1 was compared between OSCC samples and paracancerous samples from The Cancer Genome Atlas (TCGA) database. Additionally, the lnc-METRNL-1 expression in cell lines was detected by using qRT-PCR. The overall survival (OS) was estimated based on the Kaplan-Meier and the immune cell infiltration was evaluated using CIBERSORT. Significantly enriched biological pathways were identified by Gene-set enrichment analysis (GSEA). Differential expression analysis was done in edgeR package. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of differential expression genes were conducted using DAVID version 6.8. The lnc-METRNL-1 expression in OSCC was significantly lower than that in paracancerous samples, and patients with low lnc-METRNL-1 expression had poorer OS. Additionally, lnc-METRNL-1 was significantly down-regulated in OSCC cell lines compared with normal cell line. High expression of lnc-METRNL-1 was closely associated with the activation of several tumor metabolic and metabolism-related pathways. Besides, aberrant lnc-METRNL-1 expression was found to be related to the differential infiltration of immune cells in tumor tissue, such as regulatory T cells, and Macrophages. Low lnc-METRNL-1 expression was probably a poor prognostic biomarker for OSCC patients. Moreover, the potential role of lnc-METRNL-1 in the onset of OSCC was partly revealed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03674-0.

The anti-inflammatory activity of the compounds isolated from Dichroa febrifuga leaves

Dichroa febrifuga Lour. is a traditional medicinal herb that has been applied in the treatment of malaria and some other infectious diseases. Studies recently have focused on the anti-inflammation of the extracts of Dichroa febrifuga Lour. although there have not many reports about which compounds play the essential role. Therefore, in this study, we isolated hydrangenoside C (1), isoarborinol (2), and methyl 1,3,4,6-tetra-O-acetyl-fructofuranoside (3) from the leaves of Dichroa febrifuga. Subsequently, the anti-inflammatory property of 1-3 was assessed using an in vivo assay of edema mouse model which was induced by carrageenan. Out of the three, 2 inhibited the edema effectively and dose-dependently, similarly to diclofenac while there was no obvious activity observed in 1 and 3. The in silico results demonstrated that 2 enables binding to 5-LOX and PLA2 via generating h-bonds. This is the first study to mention the anti-inflammation of 2 in Dichroa febrifuga Lour., and would be a contribution to further studies to elucidate the promising bioactivities of this compound.

Inflammatory signalling in atrial cardiomyocytes: a novel unifying principle in atrial fibrillation pathophysiology

Inflammation has been implicated in atrial fibrillation (AF), a very common and clinically significant cardiac rhythm disturbance, but its precise role remains poorly understood. Work performed over the past 5 years suggests that atrial cardiomyocytes have inflammatory signalling machinery - in particular, components of the NLRP3 (NACHT-, LRR- and pyrin domain-containing 3) inflammasome - that is activated in animal models and patients with AF. Furthermore, work in animal models suggests that NLRP3 inflammasome activation in atrial cardiomyocytes might be a sufficient and necessary condition for AF occurrence. In this Review, we evaluate the evidence for the role and pathophysiological significance of cardiomyocyte NLRP3 signalling in AF. We first summarize the evidence for a role of inflammation in AF and review the biochemical properties of the NLRP3 inflammasome, as defined primarily in studies of classic inflammation. We then briefly consider the broader evidence for a role of inflammatory signalling in heart disease, particularly conditions that predispose individuals to develop AF. We provide a detailed discussion of the available information about atrial cardiomyocyte NLRP3 inflammasome signalling in AF and related conditions and evaluate the possibility that similar signalling might be important in non-myocyte cardiac cells. We then review the evidence on the role of active resolution of inflammation and its potential importance in suppressing AF-related inflammatory signalling. Finally, we consider the therapeutic potential and broader implications of this new knowledge and highlight crucial questions to be addressed in future research.

5-Lipoxygenase Contributes to Benzo[a]pyrene-Induced Cytotoxicity and DNA Damage in Human Bronchial Epithelial Cells

Metabolic activation of indirect-acting carcinogens in target organs is a recognized mechanism of carcinogenesis. This study aimed to determine the role of benzo[a]pyrene (BaP) metabolism enzymes lipoxygenase (LOX), cytochrome P4501A1 (CYP1A1), and prostaglandin synthetase (PGS) in the cytotoxicity and DNA damage induced by BaP in the human tracheobronchial epithelial cells (HBECs) using RNA interference strategy and metabolic enzyme inhibitors. Our results showed that in three epithelial cell lines (HBE, HTR-8/SVneo, and HaCat), BaP significantly upregulated 5-LOX protein expression. 15-LOX-2 expression also increased with increasing BaP concentration, but the change was less pronounced than that of 5-LOX. BaP caused significant cytotoxicity, DNA strand breaks, and 8-hydroxy-2'-deoxyguanosine formation in HBE, which was inhibited by 5-LOXshRNA, a specific inhibitor of 5-LOX (AA861), the CYP1A1 inhibitor α-naphthoflavone, and the PGS inhibitor naproxen. The protective effects of 5-LOXshRNA were stronger than AA861, naproxen and α-naphthoflavone. We conclude that BaP may be activated more by 5-LOX than by CYP1A1 and PGS to produce cytotoxicity and DNA damage in HBE.

Oxylipin status, before and after LC n-3 PUFA supplementation, has little relationship with skeletal muscle biology in older adults at risk of sarcopenia

INTRODUCTION

Oxylipins form endogenously via the oxygenation of long-chain polyunsaturated fatty acids (LC PUFA). Several oxylipins are highly bioactive molecules and are believed to be key mediators of LC PUFA metabolism in the body. However, little is known in relation to whether oxylipins mediate alterations in skeletal muscle mass and function. The objective of this study was to determine if a relationship exists between the oxylipin profile and skeletal muscle biology in healthy older adults at risk of sarcopenia and determine if this changes in response to LC n-3 PUFA supplementation.

MATERIALS AND METHODS

This exploratory study investigated the baseline correlations between LC n-3, n-6 and n-9 PUFA-derived oxylipins and markers of muscle biology. For this, the concentration of 79 free (i.e., non-esterified) oxylipins was quantified in human plasma by liquid chromatography-mass spectrometry (LC-MS) and retrospectively correlated to phenotypic outcomes obtained pre-intervention from the NUTRIMAL study (n = 49). After examining the baseline relationship, the potential effect of supplementation (LC n-3 PUFA or an isoenergetic control made of high-oleic sunflower and corn oil) was evaluated by correlating the change in oxylipins concentration and the change in markers of skeletal muscle biology. The relationship between oxylipins pre- and post-intervention and their parent PUFA were also examined.

RESULTS

At baseline, the hydroxy product of mead acid (n-9 PUFA), 5-HETrE, was negatively correlated to the phenotypic parameters appendicular lean mass index (ALMI) (p = 0.003, r=-0.41), skeletal muscle mass index (SMMI) (p = 0.001, r=-0.46), handgrip strength (HGS) (p<0.001, r = 0.48) and isometric knee extension (p<0.001, r=-0.48). Likewise, LC n-6 PUFA hydroxy‑PUFA were negatively correlated to HGS (i.e., 12-HETrE, p = 0.002, r=-0.42, and 5- and 11-HETE, p = 0.006, r=-0.47 and p<0.001, r=-0.50 respectively), single leg stand time (i.e., 12-HETrE, p = 0.006, r=-0.39 and 16-HETE, p = 0.002, r=-0.43), and five-time-sit-to-stand test (FTST) performance (16-HETE, p = 0.006, r = 0.39), and positively correlated to gait speed (i.e., 12-HETrE, p = 0.007, r = 0.38 and 16-HETE, p = 0.006, r = 0.39). LC n-3 PUFA supplementation increased eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived oxylipins and reduced n-6 PUFA derived oxylipins. Parameters of skeletal muscle mass and strength were not significantly altered in either LC n-3 PUFA or placebo groups. Changes in plasma oxylipins concentrations were closely related to changes in their parent PUFA, assessed in the erythrocyte membrane, but were not associated with any changes in skeletal muscle parameters.

DISCUSSION AND CONCLUSION

At baseline, the status n-9 (5-HETrE) and n-6 PUFA derivates [12-HETrE, and 5-, 11- and 16-HETE], but not n-3 PUFA derived oxylipins, were associated with poor skeletal muscle health parameters (i.e., mass and strength). However, these correlations were no longer present when correlating relative changes from pre to post timepoints. An independent cohort validation is needed to explore baseline correlations further. Further research is warranted to assess other biological mechanisms by which LC n-3 PUFA might affect muscle biology.

Free radicals: Relationship to Human Diseases and Potential Therapeutic applications

Reactive species are highly-reactive enzymatically, or non-enzymatically produced compounds with important roles in physiological and pathophysiological cellular processes. Although reactive species represent an extensively researched topic in biomedical sciences, many aspects of their roles and functions remain unclear. This review aims to systematically summarize findings regarding the biochemical characteristics of various types of reactive species and specify the localization and mechanisms of their production in cells. In addition, we discuss the specific roles of free radicals in cellular physiology, focusing on the current lines of research that aim to identify the reactive oxygen species-initiated cascades of reactions resulting in adaptive or pathological cellular responses. Finally, we present recent findings regarding the therapeutic modulations of intracellular levels of reactive oxygen species, which may have substantial significance in developing novel agents for treating several diseases.

Cecropia pachystachya Trécul: identification, isolation of secondary metabolites, in silico study of toxicological evaluation and interaction with the enzymes 5-LOX and α-1-antitrypsin

Cecropia pachystachya Tréc., popularly known as embaúba, belongs to the Cecropiaceae family and is used by the native population in the treatment of bronchitis, asthma, high blood pressure, fever, and as a diuretic. The pharmacological actions including anti-inflammatory, antioxidant, cardiotonic and sedative were previously reported. The objective of this study was to (1) isolate and identify bioactive compounds extracted from the ethanolic extract of C. pachystachya roots (ERCP), as well as (2) verify the affinity of these metabolites with the enzymes 5-lipoxygenase (5-LOX) and α-1-antitrypsin through in silico tests. Isolation and/or identification were performed using GC-MS, HPLC, Infrared (IR), and nuclear magnetic resonance (NMR) techniques. After isolation and identification of the active compounds, these substances were subjected to the in silico investigation that proceeded by performing PreADMET simulations and molecular docking calculations. The bioactive compounds identified were 1-(+)-ascorbic acid 2,6-dihexadecanoate, ethyl hexadecanoate, ethyl (9E,12E)-octadec-9,12-dienoate, ethyl (Z)-octadec-9-enoate and ethyl octadecanoate by GC-MS; chlorogenic acid, catechin, epicatechin, syringaldehyde by HPLC; β-sitosterol, sitostenone, beccaridiol, tormentic acid, lupeol, α- and β-amyrin by classical chromatography, IR, ¹H and ¹³C NMR techniques. The ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties were determined for each bioactive compound. Tormentic acid demonstrated a greater affinity for 5-LOX enzyme while sitostenone demonstrated a higher affinity for the α-1-antitrypsin enzyme. Our findings demonstrated a diverse range of secondary metabolites isolated from C. pachystachya that showed relevant interactions with the enzymes 5-LOX and α-1-antitrypsin. Thus, "embaúba" may be employed in in vivo experimental studies as a form of alternative treatment for chronic lung diseases.Abbreviations: ADT: Autodock Tools; BBB: Blood-brain barrier; CaCo2: Human colonic adenocarcinoma cells; CC: Classic/open Column; TLC: Thin Layer Chromatography; CD40: Differentiation Cluster 40; CENAUREMN: Centro Nordestino de Aplicação e Uso da Ressonância Magnética Nuclear; GC-MS: Gas Chromatography coupled to mass spectrometry; HPLC: High-Perfomance Liquid Chromatography; CYP2C9, CYP2C19, CYP2D6 and CYP3A4: Cytochrome P450 isoenzymes; COPD: Chronic Obstructive Pulmonary Disease; DRX-500: X-Ray Diffraction - 500; ERCP: Ethanolic extract of the roots of C. pachystachya; FAPEPI: Fundação de Amparo à Pesquisa do Piauí; HIA: Human Intestinal Absorption; IR: Infrared; Ki: Inhibition constant; 5-LOX: 5-Lipoxygenase; mM: miliMolar; nM: nanoMolar; OECD423: acute toxic class method; PDB: Protein Data Bank; P-gP: P-glycoprotein; PM2,5: Small inhalable particles 2,5; PPB: Plasm Protein Binding; PreADMET: Prediction Absorption, Distribution, Metabolization, Excretion and Toxicity; NMR: Nuclear Magnetic Resonance; +S9: with metabolic activation; -S9: no metabolic activation; SisGen: Sistema Nacional de Gestão de Patrimônio Genético e do Conhecimento Tradicional Associado; R_T: Retention time; TA100: Ames test with TA100 cells line; TA1535: Ames test with cells of the TA1535 cell line; UESPI: State University of Piauí; V79: lung fibroblast cells; ΔG: Gibbs free energy (Kcal/mol); μM: microMolar.

Computational Design, Synthesis, and Pharmacological Evaluation of Naproxen-Guaiacol Chimera for Gastro-Sparing Anti-Inflammatory Response by Selective COX2 Inhibition

The 4-allyl guaiacol is a natural phenolic molecule that has been widely studied for its antioxidant capacity against reactive-oxygen-species-mediated cellular damage. Therefore, we hypothesized that concomitant use of an antioxidant and NSAID may decrease the risk of gastrointestinal toxicity and make the therapy safer. To address the gastrointestinal toxicity of conventional NSAIDs, a new S-naproxen-4-allyl guaiacol chimera (MAS-1696) was computationally developed, chemically synthesized, and tested for anti-inflammatory effectiveness and gastrointestinal safety. The inhibitory potency of MAS-1696 tested against cyclooxygenase-2 (COX2), 15-lipoxygenase-2 (15-LOX2), and lipoxygenase-5 (5-LOX) in vitro revealed a stronger inhibition of COX2. Furthermore, the MAS-1696 chimera increased the COX selectivity index by 23% as compared to the parent compound naproxen, implying higher efficacy and gastric safety. In vivo data showed that MAS-1696 was less likely to cause gastrointestinal harm than naproxen while also exerting anti-inflammatory and analgesic effects equivalent to or superior to naproxen. In conclusion, MAS-1696 is orally active, bio-labile, and crystalline, making it a medication that may be administered orally.

Dietary anthocyanins balance immune signs in osteoarthritis and obesity - update of human in vitro studies and clinical trials

Anthocyanins are known to change ligand-receptor bindings, cell membrane permeability, and intracellular signaling pathways. The beneficial effects of dietary anthocyanins have been chronologically demonstrated in interventional and observational studies, including fourteen human chondrocyte studies and related cell culture assays, nineteen human clinical trials in osteoarthritis patients, seven in vivo obesity assays, nineteen in vitro assays in preadipocytes and related cells, and twenty-two clinical trials in overweight/obese subjects, which are critically discussed in this update. Strawberries, cherries, berries, pomegranate, tropical fruits, rosehip, purple rice, purple corn, red beans, and black soybean, together with cyanidin, delphinidin, malvidin, peonidin, some 3-O-glycosides, metabolites, and acylated anthocyanins from a potato cultivar have shown the best outcomes. The set of these five key tests and clinical trials, taken together, contributes to the understanding of the underlying mechanisms and pathways involved. Furthermore, this set shows the value of anthocyanins in counteracting the progression of osteoarthritis/obesity. The interplay between the inflammation of osteoarthritis and obesity, and the subsequent regulation/immunomodulation was performed through isolated and food anthocyanins. The antioxidant, anti-inflammatory, and immunomodulatory properties of anthocyanins explain the findings of the studies analyzed. However, further interventional studies should be conducted to finally establish the appropriate doses for anthocyanin supplementation, dose-response, and length of consumption, to include dietary recommendations for osteoarthritis/obese patients for preventive and management purposes.

Free docosahexaenoic acid promotes ferroptotic cell death via lipoxygenase dependent and independent pathways in cancer cells

PURPOSE

Ferroptosis is a form of regulated cell death that has the potential to be targeted as a cancer therapeutic strategy. But cancer cells have a wide range of sensitivities to ferroptosis, which limits its therapeutic potential. Accumulation of lipid peroxides determines the occurrence of ferroptosis. However, the type of lipid involved in peroxidation and the mechanism of lipid peroxide accumulation are less studied.

METHODS

The effects of fatty acids (10 μM) with different carbon chain length and unsaturation on ferroptosis were evaluated by MTT and LDH release assay in cell lines derived from prostate cancer (PC3, 22RV1, DU145 and LNCaP), colorectal cancer (HT-29), cervical cancer (HeLa) and liver cancer (HepG2). Inhibitors of apoptosis, necroptosis, autophagy and ferroptosis were used to determine the type of cell death. Then the regulation of reactive oxygen species (ROS) and lipid peroxidation by docosahexaenoic acid (DHA) was measured by HPLC-MS and flow cytometry. The avtive form of DHA was determined by siRNA mediated gene silencing. The role of lipoxygenases was checked by inhibitors and gene silencing. Finally, the effect of DHA on ferroptosis-mediated tumor killing was verified in xenografts.

RESULTS

The sensitivity of ferroptosis was positively correlated with the unsaturation of exogenously added fatty acid. DHA (22:6 n-3) sensitized cancer cells to ferroptosis-inducing reagents (FINs) at the highest level in vitro and in vivo. In this process, DHA increased ROS accumulation, lipid peroxidation and protein oxidation independent of its membrane receptor, GPR120. Inhibition of long chain fatty acid-CoA ligases and lysophosphatidylcholine acyltransferases didn't affect the role of DHA. DHA-involved ferroptosis can be induced in both arachidonate lipoxygenase 5 (ALOX5) negative and positive cells. Down regulation of ALOX5 inhibited ferroptosis, while overexpression of ALOX5 promoted ferroptosis.

CONCLUSION

DHA can effectively promote ferroptosis-mediated tumor killing by increasing intracellular lipid peroxidation. Both ALOX5 dependent and independent pathways are involved in DHA-FIN induced ferroptosis. And during this process, free DHA plays an important role.

Evidence of Failed Resolution Mechanisms in Arrhythmogenic Inflammation, Fibrosis and Right Heart Disease

Inflammation is a complex program of active processes characterized by the well-orchestrated succession of an initiation and a resolution phase aiming to promote homeostasis. When the resolution of inflammation fails, the tissue undergoes an unresolved inflammatory status which, if it remains uncontrolled, can lead to chronic inflammatory disorders due to aggravation of structural damages, development of a fibrous area, and loss of function. Various human conditions show a typical unresolved inflammatory profile. Inflammatory diseases include cancer, neurodegenerative disease, asthma, right heart disease, atherosclerosis, myocardial infarction, or atrial fibrillation. New evidence has started to emerge on the role, including pro-resolution involvement of chemical mediators in the acute phase of inflammation. Although flourishing knowledge is available about the role of specialized pro-resolving mediators in neurodegenerative diseases, atherosclerosis, obesity, or hepatic fibrosis, little is known about their efficacy to combat inflammation-associated arrhythmogenic cardiac disorders. It has been shown that resolvins, including RvD1, RvE1, or Mar1, are bioactive mediators of resolution. Resolvins can stop neutrophil activation and infiltration, stimulate monocytes polarization into anti-inflammatory-M2-macrophages, and activate macrophage phagocytosis of inflammation-debris and neutrophils to promote efferocytosis and clearance. This review aims to discuss the paradigm of failed-resolution mechanisms (FRM) potentially promoting arrhythmogenicity in right heart disease-induced inflammatory status.

Peperomia pellucida (L.) Kunth and eye diseases: A review on phytochemistry, pharmacology and toxicology

Peperomia pellucida (L.) Kunth is a medicinal plant used to manage inflammatory illnesses such as conjunctivitis, and gastrointestinal and respiratory tract disorders in tropical and subtropical regions. However, little is known about its pharmacological mechanism of action against eye diseases. This review aims to critically discuss the phytochemistry, pharmacology and toxicology of P. pellucida as well as its roles in the treatment of cataract, glaucoma and diabetic retinopathy. Recent developments in the uses of P. pellucida for healthcare and nutraceutical products by the pharmaceutical industry are also covered in this review. For this review, a literature search was performed with PubMed, ScienceDirect, SciFinder Scholar and Scopus databases, using relevant keywords. Among the various phytochemicals identified from P. pellucida, β-caryophyllene, carotol, dillapiole, ellagic acid, pellucidin A, phytol and vitexin exhibit strong pharmacological activities within the mitogen-activated protein kinase and nuclear factor-κB signalling pathways in inflammatory eye diseases. The antihypertensive, anti-inflammatory, antioxidant, antihyperglycemic and anti-angiogenic activities displayed by P. pellucida extracts in many in vitro, in vivo and clinical studies suggest its potential role in the management of inflammatory eye diseases. P. pellucida extract was non-toxic against normal cell lines but displayed mild toxicity in animal models. The growing public interest in P. pellucida has inspired the nutraceutical and pharmaceutical industries to process the plant into health products. Although the potential pharmacological mechanisms against eye diseases have been summarized, further studies of the interactions among constituent phytochemicals from P. pellucida within various signalling pathways shall support the use of the plant as an alternative therapeutic source.

Structure-Activity Relationship Studies of New Sinapic Acid Phenethyl Ester Analogues Targeting the Biosynthesis of 5-Lipoxygenase Products: The Role of Phenolic Moiety, Ester Function, and Bioisosterism

Sinapic acid is found in many edible plants and fruits, such as rapeseed, where it is the predominant phenolic compound. New sinapic acid phenethyl ester (SAPE) analogues were synthesized and screened as inhibitors of the biosynthesis of 5-lipoxygenase (5-LO) in stimulated HEK293 cells and polymorphonuclear leukocytes (PMNL). Inhibition of leukotriene biosynthesis catalyzed by 5-LO is a validated therapeutic strategy against certain inflammatory diseases and allergies. Unfortunately, the only inhibitor approved to date has limited clinical use because of its poor pharmacokinetic profile and liver toxicity. With the new analogues synthesized in this study, the role of the phenolic moiety, ester function, and bioisosterism was investigated. Several of the 34 compounds inhibited the biosynthesis of 5-LO products, and 20 compounds were 2-11 times more potent than zileuton in PMNL, which are important producers of 5-LO products. Compounds 5i (IC₅₀: 0.20 μM), 5l (IC₅₀: 0.20 μM), and 5o (IC₅₀: 0.21 μM) bearing 4-trifluoromethyl, methyl, or methoxy substituent at meta-position of the phenethyl moiety were 1.5 and 11.5 times more potent than SAPE (IC₅₀: 0.30 μM) and zileuton (IC₅₀: 2.31 μM), respectively. Additionally, compound 9 (IC₅₀: 0.27 μM), which was obtained after acetylation of the 4-hydroxyl of SAPE, was equivalent to SAPE and 8 times more active than zileuton. Furthermore, compound 20b (IC₅₀: 0.27 μM) obtained after the bioisosteric replacement of the ester function of SAPE by the 1,2,4-oxadiazole heterocycle was equivalent to SAPE and 8 times more active than zileuton. Thus, this study provides a basis for the rational design of new molecules that could be developed further as anti 5-LO therapeutics.

Role of arachidonic acid lipoxygenase pathway in Asthma

The arachidonic acid (AA) metabolism pathways play a key role in immunological response and inflammation diseases, such as asthma, etc. AA in cell membranes can be metabolized by lipoxygenases (LOXs) to a screen of bioactive substances that include leukotrienes (LTs), lipoxins (LXs), and eicosatetraenoic acids (ETEs), which are considered closely related to the pathophysiology of respiratory allergic disease. Studies also verified that drugs regulating AA LOXs pathway have better rehabilitative intervention for asthma. This review aims to summarize the physiological and pathophysiological importance of AA LOXs metabolism pathways in asthma and to discuss its prospects of therapeutic strategies.

Modulators of TRPM7 and its potential as a drug target for brain tumours

TRPM7 is a non-selective divalent cation channel with an alpha-kinase domain. Corresponding with its broad expression, TRPM7 has a role in a wide range of cell functions, including proliferation, migration, and survival. Growing evidence shows that TRPM7 is also aberrantly expressed in various cancers, including brain cancers. Because ion channels have widespread tissue distribution and result in extensive physiological consequences when dysfunctional, these proteins can be compelling drug targets. In fact, ion channels comprise the third-largest drug target type, following enzymes and receptors. Literature has shown that suppression of TRPM7 results in inhibition of migration, invasion, and proliferation in several human brain tumours. Therefore, TRPM7 presents a potential target for therapeutic brain tumour interventions. This article reviews current literature on TRPM7 as a potential drug target in the context of brain tumours and provides an overview of various selective and non-selective modulators of the channel relevant to pharmacology, oncology, and ion channel function.

The Anti-Allergic and Anti-Inflammatory Effects of Phlorotannins from the Edible Brown Algae, Ecklonia sp. and Eisenia sp

Because the number of people suffering from allergies has significantly increased, improved ways of treating these conditions by medical, pharmaceutical, and dietary means are required. Large numbers of studies on allergy have been conducted, and many anti-allergic compounds have been found. Phenolic compounds from terrestrial plants, including catechins and flavonoids, possess anti-allergic properties. Although polyphenols are present in some brown algae, their anti-allergic activities were not studied in detail before the 1990s. The focus was on the algal polyphenols, collectively called phlorotannins (eg., eckol, 6,6′-bieckol, 8,8′-bieckol, dieckol, and phlorofucofuroeckol-A), and research was conducted to clarify their anti-allergic activities. This review summarizes the anti-allergic effects of phlorotannins isolated from the brown alga, Eisenia nipponica, and related reports by other research groups.

Matters of the heart: Cellular sex differences

Nearly all cardiovascular diseases show sexual dimorphisms in prevalence, presentation, and outcomes. Until recently, most clinical trials were carried out in males, and many animal studies either failed to identify the sex of the animals or combined data obtained from males and females. Cellular sex in the heart is relatively understudied and many studies fail to report the sex of the cells used for in vitro experiments. Moreover, in the small number of studies in which sex is reported, most of those studies use male cells. The observation that cells from males and females are inherently different is becoming increasingly clear - either due to acquired differences from hormones and other factors or due to intrinsic differences in genotype (XX or XY). Because of the likely contribution of cellular sex differences in cardiac health and disease, here, we explore differences in mammalian male and female cells in the heart, including the less-studied non-myocyte cell populations. We discuss how the heart's microenvironment impacts male and female cellular phenotypes and vice versa, including how secretory profiles are dependent on cellular sex, and how hormones contribute to sexually dimorphic phenotypes and cellular functions. Intracellular mechanisms that contribute to sex differences, including gene expression and epigenetic remodeling, are also described. Recent single-cell sequencing studies have revealed unexpected sex differences in the composition of cell types in the heart which we discuss. Finally, future recommendations for considering cellular sex differences in the design of bioengineered in vitro disease models of the heart are provided.

Ginger, a Possible Candidate for the Treatment of Dementias?

As the human life expectancy increases, age-linked diseases have become more and more frequent. The worldwide increment of dementia cases demands medical solutions, but the current available drugs do not meet all the expectations. Recently the attention of the scientific community was attracted by natural compounds, used in ancient medicine, known for their beneficial effects and high tolerability. This review is focused on Ginger (Zingiber officinale) and explore its properties against Alzheimer's Disease and Vascular Dementia, two of the most common and devastating forms of dementia. This work resumes the beneficial effects of Ginger compounds, tested in computational in vitro and in vivo models of Alzheimer's Disease and Vascular Dementia, along with some human tests. All these evidences suggest a potential role of the compounds of ginger not only in the treatment of the disease, but also in its prevention.

Crosstalk between ORMDL3, serine palmitoyltransferase, and 5-lipoxygenase in the sphingolipid and eicosanoid metabolic pathways

Leukotrienes (LTs) and sphingolipids are critical lipid mediators participating in numerous cellular signal transduction events and developing various disorders, such as bronchial hyperactivity leading to asthma. Enzymatic reactions initiating production of these lipid mediators involve 5-lipoxygenase (5-LO)-mediated conversion of arachidonic acid to LTs and serine palmitoyltransferase (SPT)-mediated de novo synthesis of sphingolipids. Previous studies have shown that endoplasmic reticulum membrane protein ORM1-like protein 3 (ORMDL3) inhibits the activity of SPT and subsequent sphingolipid synthesis. However, the role of ORMDL3 in the synthesis of LTs is not known. In this study, we used peritoneal-derived mast cells isolated from ORMDL3 KO or control mice and examined their calcium mobilization, degranulation, NF-κB inhibitor-α phosphorylation, and TNF-α production. We found that peritoneal-derived mast cells with ORMDL3 KO exhibited increased responsiveness to antigen. Detailed lipid analysis showed that compared with WT cells, ORMDL3-deficient cells exhibited not only enhanced production of sphingolipids but also of LT signaling mediators LTB₄, 6t-LTB₄, LTC₄, LTB₅, and 6t-LTB₅. The crosstalk between ORMDL3 and 5-LO metabolic pathways was supported by the finding that endogenous ORMDL3 and 5-LO are localized in similar endoplasmic reticulum domains in human mast cells and that ORMDL3 physically interacts with 5-LO. Further experiments showed that 5-LO also interacts with the long-chain 1 and long-chain 2 subunits of SPT. In agreement with these findings, 5-LO knockdown increased ceramide levels, and silencing of SPTLC1 decreased arachidonic acid metabolism to LTs to levels observed upon 5-LO knockdown. These results demonstrate functional crosstalk between the LT and sphingolipid metabolic pathways, leading to the production of lipid signaling mediators.

Hybrids as NO Donors

Cinnamic acid and its derivatives have been studied for a variety of biological properties, including anti-inflammatory, antioxidant, anticancer, antihypertensive, and antibacterial. Many hybrids of cinnamic derivatives with other bioactive molecules have been synthesized and evaluated as nitric oxide (NO) donors. Since NO plays a significant role in various biological processes, including vasodilation, inflammation, and neurotransmission, NO donor groups are incorporated into the structures of already-known bioactive molecules to enhance their biological properties. In this review, we present cinnamic hybrids with NO-donating ability useful in the treatment of several diseases.

Antioxidant spiropharanone, an undescribed variant of trans-decalin spiro-γ-lactone, from pharaoh cuttlefish Sepia pharaonis: Twin inhibitors of inflammatory 5-lipoxygenase and serine protease dipeptidyl peptidase-4

Marine pharaoh cuttlefish Sepia pharaonis (family Sepiidae) is regarded as an economically important class of cephalopod in the coastal Mediterranean and Asian regions. Bioassay-guided chromatographic purification of solvent extract of S. pharaonis led to the identification of a trans-decalin based spirolactone, spiropharanone, which was characterized as 1-hydroxy-7-(4'-methoxy-3-methylbut-2-enyl)-3,9,15-trimethyl-8-oxo-octahydro-5H-spiro[furan-8,9-naphtho]-8-yl-acetate by spectroscopic techniques. Spiropharanone exhibited significantly greater anti-inflammatory activity by attenuating pro-inflammatory 5-lipoxygenase (IC₅₀ 1.02 mM) than the non-steroidal drug ibuprofen (IC₅₀ 4.61 mM, p ≤ .05). Superior antioxidant properties of spiropharanone against free radicals (EC₅₀ ~1.20 mM) and other oxidants (hydroxyl [EC₅₀ 0.97 mM] and superoxide [EC₅₀ 1.47 mM] scavenging) also reinforced its promising anti-inflammatory activity. The studied spiropharanone also exhibited significant attenuation toward insulin secretion regulating enzyme dipeptidyl peptidase-4 (IC₅₀ 0.92 mM) recognizing its anti-hyperglycemic potential. Significantly higher electronic properties (topological polar surface area ~100) combined with balanced hydrophilic-lipophilic properties (partition coefficient of logarithmic octanol-water ~3) and lesser docking parameters of spiropharanone demonstrated that the compound could be utilized as an important bioactive lead against oxidative stress, inflammation, and hyperglycemic-related ailments. PRACTICAL APPLICATIONS: Nutritionally rich edible marine pharaoh cuttlefish Sepia pharaonis occupies a prominent place among seafood fisheries owing to the presence of bioactive nutrients and functional food ingredients. These marine cuttlefish are widely distributed along the Asian and Mediterranean coasts, and consumed as culinary delicacy for decades. An undescribed trans-decalin spirolactone, spiropharanone was isolated from the organic extract of S. pharaonis based on bioactivity-assisted sequential chromatographic fractionation. Spiropharanone displayed promising antioxidant potential along with attenuation properties against inducible pro-inflammatory 5-lipoxygenase and insulin secretion regulating enzyme dipeptidyl peptidase-4. This study established the ameliorating potential of a naturally derived marine food constituent against inflammatory and diabetic ailments, and thus anticipated as functional food lead in pharmaceutical formulations towards inflammation and maintaining glucose homeostasis.

Aspirin-Triggered Resolvin D1 Reduces Proliferation and the Neutrophil to Lymphocyte Ratio in a Mutant KRAS-Driven Lung Adenocarcinoma Model

Simple Summary

Aspirin-triggered resolvin D1 (AT-RvD1) is biosynthesised by leukocytes as a mechanism to resolve inflammation during infection and/or injury. Emerging studies reveal that AT-RvD1 also has anti-cancer properties associated with stimulating macrophage-mediated clearance of tumour debris. No study to date has investigated how AT-RvD1 influences the neutrophil to lymphocyte ratio (NLR) in lung cancer, an established marker of poor prognosis. The biosynthesis of AT-RvD1 is dependent on the ALOX5 gene, and we reveal that ALOX5 mRNA expression was markedly reduced in lung adenocarcinoma tumours. We next utilised an oncogenic Kras^G12D lung adenocarcinoma mouse model to investigate the efficacy of AT-RvD1 in vivo. We show for the first time that AT-RvD1 reduces tumour growth in the lungs of Kras^G12D mice and alters the immune landscape in tumours by reducing the NLR.

Abstract

Tumour-associated neutrophils (TANs) can support tumour growth by suppressing cytotoxic lymphocytes. AT-RvD1 is an eicosanoid that can antagonise neutrophil trafficking instigated by ALX/FPR2 ligands such as serum amyloid A (SAA). We aimed to establish whether SAA and ALOX5 expression associates with TANs and investigate the immunomodulatory actions of AT-RvD1 in vivo. MPO-positive neutrophils were quantified in tumour blocks from lung adenocarcinoma (n = 48) and control tissue (n = 20) by IHC. Tumour expression of SAA and ALOX5 were analysed by RTqPCR and an oncogenic Kras^G12D lung adenocarcinoma mouse model was used to investigate the in vivo efficacy of AT-RvD1 treatment. ALOX5 expression was markedly reduced in lung adenocarcinoma tumours. The SAA/ALOX5 ratio strongly correlated with TANs and was significantly increased in tumours harbouring an oncogenic KRAS mutation. AT-RvD1 treatment reduced tumour growth in Kras^G12D mice, which was accompanied by suppressed cellular proliferation within parenchymal lesions. In addition, AT-RvD1 significantly reduced the neutrophil to lymphocyte ratio (NLR), an established prognostic marker of poor survival in adenocarcinoma. This study identifies a novel molecular signature whereby elevated levels of SAA relative to ALOX5 favour accumulation of TANs. Furthermore, the ALOX5/5-LO enzymatic product, AT-RvD1, markedly reduced the NLR and suppressed tumour growth in Kras^G12D mice.

2-((4-((E)-1-(Hydroxyimino)ethyl)phenyl)amino)-2-oxoethyl Cinnamate

Cinnamic acid-nitric oxide (NO) donor hybrids have attracted attention, in recent years, as new pharmacological agents to treat multifactorial diseases. In the present study, hybrid oxime 5 was synthesized and its anti-lipid peroxidation and anti-lipoxygenase activities were evaluated. The new compound showed remarkable anti-LOX activity, while its antioxidant activity was quite good in comparison to the appropriate reference compounds. The examined derivative seems to be orally active in accordance to Lipinski’s rule of five. Compound 5 can be considered as a leading structure for the design and synthesis of new hybrids.

Molecular insights into lipoxygenases for biocatalytic synthesis of diverse lipid mediators

Oxylipins derived mainly from C20- and C22-polyunsaturated fatty acids (PUFAs), termed lipid mediators (LMs), are essential signalling messengers involved in human physiological responses associated with homeostasis and healing process for infection and inflammation. Some LMs involved in the resolution of inflammation and infection are termed specialized pro-resolving mediators (SPMs), which are generated by human M2 macrophages or polymorphonuclear leukocytes and have the potential to protect and treat hosts from bacterial and viral infections by phagocytosis activation. Lipoxygenases (LOXs) biosynthesize regio- and stereoselective LMs. Thus, understanding the regio- and stereoselectivities of LOXs for PUFAs at a molecular level is important for the biocatalytic synthesis of diverse LMs. Here, we elucidate the catalytic mechanisms and discuss regio- and stereoselectivities and their changes of LOXs determined by insertion direction and position of the substrate and oxygen at a molecular level for the biosynthesis of diverse human LMs. Recently, the biocatalytic synthesis of PUFAs to human LMs or analogues has been conducted using microbial LOXs. Such microbial LOXs involved in the biosynthesis of LMs are expected to exert significantly higher activity and stability than human LOXs. Diverse regio- and stereoselective LOXs can be obtained from microorganisms, which represent a wealth of genomic sources. We reconstruct the biosynthetic pathways of LOX-catalyzed LMs in humans and other organisms. Furthermore, we suggest the effective methods of biocatalytic synthesis of diverse human LMs from PUFAs or glucose by using microbial LOXs, increasing the stability and activity of LOXs, combining the reactions of LOXs, and constructing metabolic pathways.

Is Antiplatelet Therapy Contraindicated After Platelet-Rich Plasma Treatment? A Narrative Review

Background

Antiplatelet therapies are often withheld before and after platelet-rich plasma product (PRPP) administration due to theoretical concerns that therapies that inhibit the function of platelets would inhibit the effects of PRPP.

Purpose/Hypothesis

The purpose of this study was to evaluate the effect that antiplatelet therapies have on the ability of PRPP to stimulate wound healing and tissue regeneration. Our hypothesis was that antiplatelet therapies would have highly heterogeneous effects on the biological activity of PRPP.

Study Design

Narrative review.

Methods

The Medline database was searched via PubMed to identify all studies related to PRPP and antiplatelet therapies, yielding 1417 publications. After the search was confined to articles published after 1995, there were 901 articles remaining. All abstracts were then screened to identify animal or human clinical studies that focused on growth factor or inflammatory cytokine production or treatment outcomes. We limited our analysis to studies reporting on orthopaedic pathologies and in vitro studies of antiplatelet therapies. Ultimately, 12 articles fit the search criteria.

Results

The majority of studies reported on the use of nonsteroidal anti-inflammatory drugs as antiplatelet therapy. The majority of studies were in vitro analyses of growth factors, inflammatory cytokines, or cell viability, whereas 1 study examined clinical outcomes in an animal model. None of the studies investigated clinical outcomes in humans. All of the studies showed no effect or mixed effects of antiplatelet therapies on PRPP efficacy. One study showed PRPP recovery to baseline function after a 1-week washout period.

Conclusion

The literature did not provide support for the common clinical practice of withholding antiplatelet therapies in patients being treated with PRPP.

A functional variant of the long noncoding RNA AL110200 is associated with the risk of ischaemic stroke recurrence

BACKGROUND AND PURPOSE

This study aimed to test the hypothesis that long noncoding RNA (lncRNA) AL110200 exerts a proinflammatory effect on atherosclerosis and that the variant rs901681 contributes to ischaemic stroke incidence and recurrence.

METHODS

The expression of AL110200 was analyzed in THP-1 cells treated with oxidized low-density lipoprotein and in human peripheral blood in a coronary heart disease and control population to determine the role of AL110200 in atherosclerosis. The effect of AL110200 on cell adhesion and invasion was tested. The plasma level of leukotriene B4 and rs901681 genotype distribution were assessed in 220 participants. In 1004 ischaemic stroke patients and 1434 controls, the association between rs901681 and stroke incidence was analyzed by logistic regression, and the association of rs901681 and stroke prognosis was analyzed using Kaplan-Meier analysis and the Cox proportional hazards model.

RESULTS

Increased expression of AL110200 was observed in THP-1 cells under oxidized low-density lipoprotein treatment. Knockdown of AL110200 reduced the adhesive and invasive ability of THP-1 cells. AL110200 expression in peripheral blood was significantly higher in the coronary heart disease group than in the controls. The GG genotype of rs901681 is associated with reduced plasma leukotriene B4. In the ischaemic stroke population, rs901681 was not associated with ischaemic stroke incidence (p = 0.686). Patients carrying rs901681 GG had a lower risk for stroke recurrence at age ≥60 years (p = 0.001), cardiovascular stroke death (p = 0.022) and all-cause mortality (p = 0.034) in the all-age group.

CONCLUSIONS

AL110200 might exert a proinflammatory effect on atherosclerosis, and the variant rs901681 might be a strong predictor of stroke prognosis in ischaemic stroke patients.

Withania somnifera (L.) Dunal: Opportunity for Clinical Repurposing in COVID-19 Management

As the COVID-19 pandemic is progressing, the therapeutic gaps in conventional management have highlighted the need for the integration of traditional knowledge systems with modern medicine. Ayurvedic medicines, especially Ashwagandha (Withania somnifera (L.) Dunal, WS), may be beneficial in the management of COVID-19. WS is a widely prescribed Ayurvedic botanical known as an immunomodulatory, antiviral, anti-inflammatory, and adaptogenic agent. The chemical profile and pharmacological activities of WS have been extensively reported. Several clinical studies have reported its safety for use in humans. This review presents a research synthesis of in silico, in vitro, in vivo, and clinical studies on Withania somnifera (L.) Dunal (WS) and discusses its potential for prophylaxis and management of COVID-19. We have collated the data from studies on WS that focused on viral infections (HIV, HSV, H1N1 influenza, etc.) and noncommunicable diseases (hypertension, diabetes, cancer, etc.). The experimental literature indicates that WS has the potential for 1) maintaining immune homeostasis, 2) regulating inflammation, 3) suppressing pro-inflammatory cytokines, 4) organ protection (nervous system, heart, lung, liver, and kidney), and 5) anti-stress, antihypertensive, and antidiabetic activities. Using these trends, the review presents a triangulation of Ayurveda wisdom, pharmacological properties, and COVID-19 pathophysiology ranging from viral entry to end-stage acute respiratory distress syndrome (ARDS). The review proposes WS as a potential therapeutic adjuvant for various stages of COVID-19 management. WS may also have beneficial effects on comorbidities associated with the COVID-19. However, systematic studies are needed to realize the potential of WS for improving clinical outcome of patients with COVID-19.

Single Cell Gene Expression Analysis in a 3D Microtissue Liver Model Reveals Cell Type-Specific Responses to Pro-Fibrotic TGF-β1 Stimulation

3D cell culture systems are widely used to study disease mechanisms and therapeutic interventions. Multicellular liver microtissues (MTs) comprising HepaRG, hTERT-HSC and THP-1 maintain multicellular interactions and physiological properties required to mimic liver fibrosis. However, the inherent complexity of multicellular 3D-systems often hinders the discrimination of cell type specific responses. Here, we aimed at applying single cell sequencing (scRNA-seq) to discern the molecular responses of cells involved in the development of fibrosis elicited by TGF-β1. To obtain single cell suspensions from the MTs, an enzymatic dissociation method was optimized. Isolated cells showed good viability, could be re-plated and cultured in 2D, and expressed specific markers determined by scRNA-seq, qRT-PCR, ELISA and immunostaining. The three cell populations were successfully clustered using supervised and unsupervised methods based on scRNA-seq data. TGF-β1 led to a fibrotic phenotype in the MTs, detected as decreased albumin and increased αSMA expression. Cell-type specific responses to the treatment were identified for each of the three cell types. They included HepaRG damage characterized by a decrease in cellular metabolism, prototypical inflammatory responses in THP-1s and extracellular matrix remodeling in hTERT-HSCs. Furthermore, we identified novel cell-specific putative fibrosis markers in hTERT-HSC (COL15A1), and THP-1 (ALOX5AP and LAPTM5).

Dimethyl fumarate induces ferroptosis and impairs NF-κB/STAT3 signaling in DLBCL

Despite the development of novel targeted drugs, the molecular heterogeneity of diffuse large B-cell lymphoma (DLBCL) still poses a major therapeutic challenge. DLBCL can be classified into at least two major subtypes, i.e. germinal center B-cell-like (GCB) and the aggressive activated B-cell-like (ABC) DLBCL, each characterized by specific gene expression profiles and mutation patterns. Here we demonstrate a broad anti-tumor effect of dimethyl fumarate (DMF) on both DLBCL subtypes, which is mediated by the induction of ferroptosis, a form of cell death driven by the peroxidation of phospholipids. Due to high expression of arachidonate 5-lipoxygenase in concert with low glutathione and glutathione peroxidase 4 levels, DMF induces lipid peroxidation and thus ferroptosis particularly in GCB DLBCL. In ABC DLBCL cells, which are addicted to NF-κB and STAT3 survival signaling, DMF treatment efficiently inhibits the activity of the IKK complex and JAK kinases. Interestingly, the BCL-2 specific BH3 mimetic ABT-199 and an inhibitor of ferroptosis suppressor protein 1 synergize with DMF in inducing cell death in DLBCL. Collectively, our findings identify the clinically approved drug DMF as a promising novel therapeutic option in the treatment of both GCB and ABC DLBCL.

Comprehensive characterization of protein-protein interactions perturbed by disease mutations

Technological and computational advances in genomics and interactomics have made it possible to identify how disease mutations perturb protein-protein interaction (PPI) networks within human cells. Here, we show that disease-associated germline variants are significantly enriched in sequences encoding PPI interfaces compared to variants identified in healthy participants from the projects 1000 Genomes and ExAC. Somatic missense mutations are also significantly enriched in PPI interfaces compared to noninterfaces in 10,861 tumor exomes. We computationally identified 470 putative oncoPPIs in a pan-cancer analysis and demonstrate that oncoPPIs are highly correlated with patient survival and drug resistance/sensitivity. We experimentally validate the network effects of 13 oncoPPIs using a systematic binary interaction assay, and also demonstrate the functional consequences of two of these on tumor cell growth. In summary, this human interactome network framework provides a powerful tool for prioritization of alleles with PPI-perturbing mutations to inform pathobiological mechanism- and genotype-based therapeutic discovery.

Iron Coordination Properties of Gramibactin as Model for the New Class of Diazeniumdiolate Based Siderophores

Gramibactin (GBT) is an archetype for the new class of diazeniumdiolate siderophores, produced by Paraburkholderia graminis, a cereal-associated rhizosphere bacterium, for which a detailed solution thermodynamic study exploring the iron coordination properties is reported. The acid-base behavior of gramibactin as well as its complexing ability toward Fe3+ was studied over a wide range of pH values (2≤pH≤11). For the latter the ligand-competition method employing EDTA was used. Only two species are formed: [Fe(GBT)]- (pH 2 to 9) and [Fe(GBT)(OH)2 ]3- (pH≥9). The formation of [Fe(GBT)]- and its occurrence in real systems was confirmed by LC-HRESIMS analysis of the bacteria culture broth extract. The sequestering ability of gramibactin was also evaluated in terms of the parameters pFe and pL0.5 . Gramibactin exhibits a higher sequestering ability toward Fe3+ than EDTA and of the same order of magnitude as hydroxamate-type microbial siderophores, but smaller than most of the catecholate-type siderophores and much higher than the most known phytosiderophores.

Cytokine Storm and Mucus Hypersecretion in COVID-19: Review of Mechanisms

Mucus is an integral part of the respiratory physiology. It protects the respiratory tract by acting as a physical barrier against inhaled particles and microbes. Excessive inflammation in conditions such as COVID-19 can result in over-production of mucus which obstructs the airway. Build-up of mucus can also contribute to recurrent airway infection, causing further obstruction. This article summarizes the current understanding and knowledge of respiratory mucus production and proposes the role of cytokine storm in inducing sudden mucus hypersecretion in COVID-19. Based on these cascades, the active constituents that inhibit or activate several potential targets are outlined for further research. These may be explored for the discovery and design of drugs to combat cytokine storm and its ensuing complications.

Inflammation Drives Alzheimer's Disease: Emphasis on 5-lipoxygenase Pathways

It is a known fact that inflammation affects several physiological processes, including the functioning of the central nervous system. Additionally, impairment of lipid mechanisms/pathways have been associated with a number of neurodegenerative disorders and Alzheimer's Disease (AD) is one of them. However, much attention has been given to the link between tau and beta- amyloid hypothesis in AD pathogenesis/prognosis. Increasing evidences suggest that biologically active lipid molecules could influence the pathophysiology of AD via a different mechanism of inflammation. This review intends to highlight the role of inflammatory responses in the context of AD with the emphasis on biochemical pathways of lipid metabolism enzyme, 5-lipoxygenase (5- LO).

Targeting Leukotrienes as a Therapeutic Strategy to Prevent Comorbidities Associated with Metabolic Stress

Leukotrienes (LTs) are potent lipid mediators that exert a variety of functions, ranging from maintaining the tone of the homeostatic immune response to exerting potent proinflammatory effects. Therefore, LTs are essential elements in the development and maintenance of different chronic diseases, such as asthma, arthritis, and atherosclerosis. Due to the pleiotropic effects of LTs in the pathogenesis of inflammatory diseases, studies are needed to discover potent and specific LT synthesis inhibitors and LT receptor antagonists. Even though most clinical trials using LT inhibitors or antagonists have failed due to low efficacy and/or toxicity, new drug development strategies are driving the discovery for LT inhibitors to prevent inflammatory diseases. A newly important detrimental role for LTs in comorbidities associated with metabolic stress has emerged in the last few years and managing LT production and/or actions could represent an exciting new strategy to prevent or treat inflammatory diseases associated with metabolic disorders. This review is intended to shed light on the synthesis and actions of leukotrienes, the most common drugs used in clinical trials, and discuss the therapeutic potential of preventing LT function in obesity, diabetes, and hyperlipidemia.