5-LOX Expression Research Articles

Arachidonic Acid Induces the Migration of MDA-MB-231 Cells by Activating Raft-associated Leukotriene B4 Receptors.

The migration of tumor cells is critical in spreading cancers through the lymphatic nodes and circulatory systems. Although arachidonic acid (AA) and its soluble metabolites have been shown to induce the migration of breast and colon cancer cells, the mechanism by which it induces such migration has not been fully understood. The effect of AA on migratory responses of the MDA-MB-231 cell line (a triple-negative breast cancer cell) was examined and compared with MCF-7 (estrogen-receptor positive) breast cancer cells to elucidate the mechanism of AA-induced migration. Migrations of breast cancer cells were examined with the help of wound-healing assays. AA-induced eicosanoid synthesis was monitored by RP-HPLC. Cellular localizations of lipoxygenase and lipid rafts were assessed by immunoblot and confocal microscopy. AA treatment stimulated the synthesis of leukotriene B4 (LTB4) and HETE-8, but lowered the levels of prostaglandin E2 (PGE2), prostaglandin D2 (PGD2), and HETE-5 in MDA-MB-231 cells. Further analysis indicated that AA increased the expression of 5-lipoxygenase (5-LOX) in this cell line and inhibiting its expression by small molecule inhibitors lowered the production of LTB4 and reduced migration. In contrast, MCF-7 cells did not show any appreciable changes in eicosanoid synthesis, 5-LOX expression, or cellular migration. Our results suggest that AA treatment activates the BLT1 receptor (present in membrane microdomains) and stimulates the synthesis of LTB4 production, which is likely to be associated with the migration of MDA-MB-231 cells.

Evaluation of anti-inflammatory and immunomodulatory effects of Premna integrifolia extracts and assay-guided isolation of a COX-2/5-LOX dual inhibitor

Premna integrifolia (Agnimantha brihat) is a traditional medicinal plant with a prominent place in Ayurveda, Siddha and Unani systems of medicine. In this study we have evaluated the anti-inflammatory and immunomodulatory properties of the Premna integrifolia root extracts employing cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and 5-lipoxygenase (5-LOX) enzyme-based assays, lymphocyte proliferation assay, pro-and anti-inflammatory cytokines measurement. Petroleum ether extract (PEE) of Premna integrifolia showed potent inhibition of COX-2 and 5-LOX with IC50 values of 6.15 μg/mL and 11.33 μg/mL respectively. In in vitro studies on RAW 264.7 cell line, PEE showed inhibition in the formation of nitric oxide (NO), pro-inflammatory cytokines (IL-1β, IL-6), prostaglandin E2 (PGE2) production, induction of anti-inflammatory cytokine (IL-2) and down-regulation of expression of COX-2, 5-LOX, TNF-α, IL-1β and iNOS. PEE also significantly reduced carrageenan-induced paw edema in mouse model of inflammation. Further, attempts in isolating the active principle(s) involved in these anti-inflammatory effects of PEE by separation on RP-HPLC resulted in the isolation of four active peaks, H1, H2, H3 and H5, inhibiting COX-1, COX-2 and 5-LOX, out of which H3 was identified as 6- hydroxy salvinolone (6-HS). Present findings reveal that PEE of roots of Premna integrifolia exhibits potent anti-inflammatory and immunomodulatory activities, which could form a potential source for development of anti-inflammatory drugs. 6-HS, a COX-2/5-LOX dual inhibitor along with other lead molecules isolated from PEE of Premna integrifolia may form lead molecules for the development of COX-LOX dual inhibitors.

Zileuton suppresses cholangiocarcinoma cell proliferation and migration through inhibition of the Akt signaling pathway.

BackgroundInflammatory lipid mediators play an important role in several cancer types. Leukotrienes (LTs), pro-inflammatory lipid mediators, are involved in chronic inflammation and cancer progression. They are derived from arachidonic acid by 5-lipoxygenase (5-LOX) activity. On the other hand, 15-lipoxygenase (15-LOX-1) converts LTs into lipoxins (LXs), pro-resolving lipid mediators. LXs are involved in the attenuation of inflammation and cancer development.PurposeWe aimed to investigate the lipid mediator pathways, especially the LTs and LXs pathways, by studying 5-LOX and 15-LOX-1 expression in human cholangiocarcinoma (CCA) tissue. We also investigated the efficiency of zileuton (5-LOX inhibitor) treatment and BML-111 (LXA4 analog) addition on CCA cell lines properties.Patients and methodsThe expression of 5-LOX and 15-LOX-1 in fifty human cholangiocarcinoma (CCA) tissue was analyzed using immunohistochemical staining. In addition, the effect of zileuton and BML-111 on CCA cell growth and migration was demonstrated using a cell viability assay and wound-healing assay, respectively. Furthermore, the molecular mechanism by which zileuton inhibits CCA cell migration was revealed using immunofluorescent staining and western blot analysis, respectively.ResultsWe demonstrate that the upregulation of 5-LOX is significantly correlated with CCA recurrent status. A positive 15-LOX-1 signal was significantly associated with a longer survival time in CCA patients. We found that co-expression of 5-LOX and 15-LOX-1 resulted in a relatively good prognosis in CCA patients. In addition, zileuton could inhibit CCA cell migration as well as BML-111. Interestingly, zileuton treatment not only downregulated 5-LOX, but also upregulated 15-LOX-1, together with reversing the epithelial-mesenchymal transition to mesenchymal-epithelial transition phenotype as observed in EMT marker western blot.ConclusionThese findings suggest that 5-LOX and 15-LOX-1 play a key role in CCA and may serve as targets for CCA therapy.

Frontline Science: Reprogramming COX-2, 5-LOX, and CYP4A-mediated arachidonic acid metabolism in macrophages by salidroside alleviates gouty arthritis.

Cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and cytochrome P450 (CYP) 4A-mediated arachidonic acid (AA) metabolism play an essential role in human inflammatory disorders. Blocking COX-2 pathway would shunt AA metabolism to the other pathway, thereby decreasing the efficacy and exacerbating adverse effects. Here we demonstrated that reprogramming COX-2, 5-LOX, and CYP4A-mediated AA metabolism in macrophages by salidroside (Sal) ameliorates monosodium urate (MSU) crystal-induced inflammation. Compared with COX-2 inhibitor celecoxib, Sal (80mg/kg) presented a superior anti-arthritic profile in MSU crystal-treated rats, accompanied with the decreased expression of COX-2, 5-LOX, and CYP4A and production of prostaglandin E2 (PGE2 ), leukotriene B4 (LTB4 ), and 20-hydroxyeicosatetraenoic acid (20-HETE) in the synovial fluid macrophages. Sal decreased representative M1 marker (iNOS and CD86, etc.) expression and M1 cytokine (TNF-α and IL-1β) production, whereas it increased M2 marker (CD206 and Arg-1) expression and M2 cytokine (TGF-β and IL-10) production. The injection of conditioned medium from MSU crystal-treated macrophages into the ankle joint of rats reproduced the gouty inflammation, which was attenuated by Sal. Mechanistically, down-regulation of COX-2, 5-LOX, and CYP4A in the RAW264.7 and NR8383 macrophages by Sal skewed macrophage polarization away from the M1 phenotype, and thereby prevented neutrophil migration and chondrocyte degradation with STAT1 and NF-κB inactivation. Conversely, overexpression of COX-2, 5-LOX, CYP4A or STAT1, or exogenous addition of IL-1β or TNF-α partially abolished these effects. Together, inhibition of COX-2, 5-LOX, and CYP4A in macrophages by Sal ameliorates MSU crystal-induced inflammation through decreasing TNF-α and IL-1β production, and may serve as a novel therapeutic strategy.

Dietary DHA amplifies LXA4 circuits in tissues and lymph node PMN and is protective in immune-driven dry eye disease.

Recently identified regulatory PMN control immune-driven dry eye disease (DED) in females by producing the arachidonic acid (ɷ−6)-derived specialized pro-resolving mediator (SPM), LXA4, in lymph nodes. Dietary ɷ−3 docosahexaenoic acid (DHA) is protective in DED but mechanisms of action remain elusive. DHA is converted to ɷ−3 SPMs by PMN via the same lipoxygenases (LOX) that generate LXA4. We investigated if dietary DHA amplifies SPM formation and affects T-effector cell function and/or regulatory PMN in DED. DED was induced in mice on a DHA-enriched or ɷ−3 deficient diet. DHA-deficiency amplified DED with marked sex-specific differences. Dietary DHA protection against dry eye disease correlated with increased PMN levels in lymph nodes, ocular tissues and unexpectedly, selective amplification of LXA4 tissue levels. Dietary DHA increased 12/15-LOX and decreased 5-LOX expression in lymph nodes and isolated lymph node-PMN, which correlated with amplified LXA4 formation. Acute DHA treatment rescued DHA-deficient females from exaggerated DED by amplifying lymph node LXA4 formation, increasing Treg and decreasing TH1 and TH17 effector cells. Our results identify DHA regulation of LXA4 producing PMN in ocular tissues and lymph nodes in health and immune disease as novel mechanism and determinant for T cell responses to routine ocular injury or stress signals.

Dietary n-3 but not n-6 fatty acids down-regulate maternal dyslipidemia induced inflammation: A three-generation study in rats

This study addresses the effects of n-3 and n-6 fatty acids in maternal dyslipidemia induced inflammation over three generation in rats. The detailed protocol for animal feeding and mating is described in the methodology. Placenta and fetal liver were isolated on the eighteenth day of gestation and delivered pups after lactation were kept on their maternal diets. Compared to control and experimental groups, high-fat fed rats (HFL) had a higher level of cytokines and eicosanoids in serum (p < 0.05). Liver and uterine expression of cPLA-2, Cox-2, 5-Lox, EP-1, BLT-1, and ICAM-1 were higher (p < 0.05) in HFL group. NF-kB and Nrf-2 levels in placenta and fetal liver were beneficially modulated by n-3 but not n-6 fatty acids. Offspring of dyslipidemic mothers’ exhibit amplified inflammatory markers when continued on diets of their mothers. Incorporation of n-3 but not n-6 fatty acids down-regulated maternal dyslipidemia induced inflammatory markers.

12-Lipoxygenase promotes invasion and metastasis of human gastric cancer cells via epithelial-mesenchymal transition.

The role of 12-lipoxygenase (12-LOX) in tumorigenesis has been well established in several types of human cancer, including gastric cancer. It was reported that epithelial-mesenchymal transition (EMT) contributes to tumor invasion and metastasis. However, whether 12-LOX promotes the invasion and metastasis of human gastric cancer cells via EMT remains to be elucidated. In the present study, the expression of 12-LOX and EMT markers, N-cadherin and E-cadherin, was evaluated in gastric cancer and adjacent normal mucosa samples by immunohistochemical analysis. 12-LOX-overexpressing gastric cancer cells were established via lentiviral transfection of SCG-7901 cells. Wound-healing and Transwell assays were performed to examine the regulation of cell metastasis and invasion by 12-LOX. Furthermore, the regulation of N-cadherin expression by 12-LOX was evaluated using reverse transcription-quantitative polymerase chain reaction and western blotting. The results revealed that the expression of 12-LOX and N-cadherin was significantly higher in gastric cancer compared with that in adjacent normal mucosa tissues (P<0.05). By contrast, the expression of E-cadherin was significantly decreased in gastric cancer compared with that in adjacent normal mucosa tissues (P<0.05). Furthermore, the expression of 12-LOX was positively associated with N-cadherin expression in gastric cancer tissues. 12-LOX-overexpressing gastric cancer cells exhibited significantly increased invasion and migration abilities compared with the empty vector and control groups. The expression of N-cadherin in 12-LOX-overexpressing gastric cancer cells was increased compared with that in the empty vector and control groups. The present study suggests that EMT may be involved in the promotion of the invasion and metastasis of human gastric cancer cells by 12-LOX.

Inhibition of COX-2/mPGES-1 and 5-LOX in macrophages by leonurine ameliorates monosodium urate crystal-induced inflammation

Cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX) and microsomal prostaglandin E synthase-1 (mPGES-1)-derived eicosanoids play an essential role in human inflammatory disorders. Here, we investigated whether inhibition of COX-2/mPGES-1 and 5-LOX in macrophages by leonurine ameliorates monosodium urate (MSU) crystal-induced inflammation. Virtual screening assay and in vitro enzyme inhibition assay showed that leonurine was a potential inhibitor of COX-2, mPGES-1 and 5-LOX. Compared with COX-2 inhibitor celecoxib, leonurine (30 mg/kg) significantly decreased ankle perimeter, gait score and neutrophil number in synovial fluid in MSU crystal-treated rats, accompanied with the decreased expression of COX-2, mPGES-1 and 5-LOX and production of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) in the synovial fluid macrophages. In addition, leonurine decreased representative M1 marker (iNOS and CD86) expression, NLRP3 inflammasome activation and M1 cytokine (TNF-α and IL-1β) production. In the in vitro cultured RAW264.7 and human monocyte-derived macrophages (MDMs), blockade of COX-2/mPGES-1 and 5-LOX by leonurine inhibited macrophage M1 polarization and NLRP3 inflammasome activation in response to MSU crystals, and thus down-regulated IL-1β and TNF-α with STAT1 and NF-κB inactivation. Conversely, these effects were partially abolished by overexpression of COX-2, mPGES-1, 5-LOX or STAT1. Furthermore, leonurine prevented a positive feedback loop between COX-2/mPGES-1/5-LOX and IL-1β/TNF-α in MSU crystal-induced inflammation. Together, simultaneous down-regulation of COX-2/mPGES-1 and 5-LOX by leonurine ameliorates MSU crystal-induced inflammation through decreasing IL-1β and TNF-α production. Our study may provide novel multi-target agents toward the arachidonic acid (AA) network for gouty arthritis therapy.

Edaravone, a free radical scavenger, protects neuronal cells’ mitochondria from ischemia by inactivating another new critical factor of the 5-lipoxygenase pathway affecting the arachidonic acid metabolism

To investigate the neuroprotective effect of edaravone was dependent on 5-lipoxygenase (5-LOX) signalling pathway or not. Middle cerebral artery occlusion (MCAO) and oxygen glucose deprivation (OGD) were established in SD rats and PC12 cells to mimic ischemic injury. In vivo, edaravone can significantly reduce neurological deficit scores, infarct volume, ROS level and expression of 5-LOX. For in vitro experiment, reduced viability, cell death which occurred via necrosis and apoptosis were shown after OGD and even severer in OGD-reperfusion (OGD-R). Interestingly, edaravone (0.01, 0.1, 1 μmol/L) and caffeic acid (5-LOX inhibitor) can dramatically attenuate OGD/OGD-R injuries. Profoundly, mitochondrial transmembrane potential was ameliorated and cristae membranes (detected by electron microscope) were swollen in OGD/OGD-R cells; however, edaravone preserved the normal ultrastructure of mitochondria and reduced ROS. Astonishingly, immunohistochemistry analyses showed that 5-LOX was first located in the cytosol, dendrites and nuclei of control cells and then translocated to the nuclear membrane after OGD/OGD-R, which indicated the activation of 5-LOX pathway. Edaravone and caffeic acid can inhibit 5-LOX translocation to the nuclear membrane after OGD/OGD-R and reduce cysteinyl leukotrienes (CysLTs), which are metabolites of 5-LOX. Our results are the first to indicate that the protective action of edaravone may function, at least in part, by inhibiting 5-LOX activation, maintaining the ultrastructure and integrated function of mitochondria, thus protecting neuronal cells from ischemia. Furthermore, the instability of mitochondria may be another critical factor in 5-LOX activation.

Gallic Acid-L-Leucine Conjugate Protects Mice against LPS-Induced Inflammation and Sepsis via Correcting Proinflammatory Lipid Mediator Profiles and Oxidative Stress.

The pathology of endotoxin LPS-induced sepsis is hallmarked by aberrant production of proinflammatory lipid mediators and nitric oxide (NO). The aim of the present study was to determine whether the new product gallic acid-L-leucine (GAL) conjugate could ameliorate the LPS-induced dysregulation of arachidonic acid metabolism and NO production. We first investigated the effects of GAL conjugate on the expression of proinflammatory enzymes and the production of proinflammatory NO and lipid mediators in mouse macrophage cell line RAW264.7, primary peritoneal macrophages, and mouse model. Western blot analyses revealed that GAL attenuated LPS-induced expression of iNOS, COX-2, and 5-LOX in a concentration-dependent manner. Consistently, probing NO-mediated fluorescence revealed that GAL antagonized the stimulatory effect of LPS on iNOS activity. By profiling of lipid mediators with ESI-MS-based lipidomics, we found that GAL suppressed LPS-induced overproduction of prostaglandin E2, prostaglandin F2, leukotriene B4, and thromboxane B2. We further discovered that GAL might exhibit anti-inflammatory activities by the following mechanisms: (1) suppressing LPS-induced activation of MAP kinases (i.e., ERK1/2, JNK, and p38); (2) reducing the production of reactive oxygen species (ROS); and (3) preventing LPS-induced nuclear translocation of transcription factors NF-κB and AP-1. Consequently, GAL significantly decreased the levels of COX-2 and iNOS expression and the plasma levels of proinflammatory lipid mediators in LPS-treated mice. GAL pretreatment enhanced the survival of mice against LPS-induced endotoxic shock. Taken together, our results suggest that GAL may be a potential anti-inflammatory drug for the treatment of endotoxemia and sepsis.

7-Ketocholesterol induces ROS-mediated mRNA expression of 12-lipoxygenase, cyclooxygenase-2 and pro-inflammatory cytokines in human mesangial cells: Potential role in diabetic nephropathy

7-Ketocholesterol (7-KCHO) is a highly proinflammatory oxysterol and plays an important role in the pathophysiology of diabetic nephropathy (DN). Lipoxygenases (LOXs) and cyclooxygenases (COXs) are also involved in the development of DN. The aim of this study was to clarify the effects of 7-KCHO on mRNA expression of LOXs and COXs as well as pro-inflammatory cytokines in human mesangial cells (HMC). We evaluated cell viability by WST-8 assay and measured mRNA expression by reverse transcription-polymerase chain reaction. Intracellular reactive oxygen species (ROS) production was evaluated by flow cytometry. Although 7-KCHO did not affect cell viability of HMC, 7-KCHO stimulated significant increases in mRNA expression of 12-LOX, COX-2 and pro-inflammatory cytokines. 7-KCHO also induced an increase in ROS production, while N-acetylcysteine partially suppressed the increase. The 12-LOX and COX-2 inhibitors also suppressed mRNA expression of cytokines. These findings may contribute to the elucidation of the molecular mechanism of the pathophysiology of DN.

Inhibition of 5-lipoxygenase inhibitor zileuton in high-fat diet-induced nonalcoholic fatty liver disease progression model.

Objective(s):Arachidonic Acid/5-lipoxygenase (AA/5-LOX) pathway connects lipid metabolism and proinflammatory cytokine, which are both related to the development and progression of nonalcoholic fatty liver disease (NAFLD). Therefore, the present study was designed to investigate the role of AA/5-LOX pathway in progression of NAFLD, and the effect of zileuton, an inhibitor of 5-LOX, in this model.Materials and Methods:Animal model for progression of NAFLD was established via feeding high saturated fat diet (HFD). Liver function, HE staining, NAFLD activity score (NAS) were used to evaluate NAFLD progression. We detected the lipid metabolism substrates: free fatty acids (FFA) and AA, products: cysteinyl-leukotrienes (CysLTs), and changes in gene and protein level of key enzyme in AA/5-LOX pathway including PLA2 and 5-LOX. Furthermore, we determined whether NAFLD progression pathway was delayed or reversed when zileuton (1-[1-(1-benzothiophen-2-yl)ethyl]-1-hydroxyurea) was administrated.Results:Rat model for progression of NAFLD was well established as analyzed by liver transaminase activities, hematoxylin-eosin (HE) staining and NAS. The concentrations of substrates and products in AA/5-LOX pathway were increased with the progression of NAFLD. mRNA and protein expression of PLA2 and 5-LOX were all enhanced. Moreover, administration of zileuton inhibited AA/5-LOX pathway and reversed the increased transamine activities and NAS.Conclusion:AA/5-LOX pathway promotes the progression of NAFLD, which can be reversed by zileuton.

Multiple mechanisms underlying neuroprotection by secretory phospholipase A2 preconditioning in a surgically induced brain injury rat model

BackgroundIntra-operative bleeding, post-operative brain edema and neuroinflammation are major complications in patients with surgical brain injury (SBI). Phospholipase A2 (PLA2) is the upstream enzyme which initiates the PLA2, 5-lipoxygenase (5-LOX) and leukotriene B4 (LTB4) inflammatory pathway. We hypothesized PLA2preconditioning (PPC) prior to SBI can activate endogenous anti-inflammatory responses to protect against SBI. This study evaluated if PPC can ameliorate neurosurgical complications and elucidated PPC-mediated possible protective mechanisms in a rat SBI model. MethodsTotal 105 adult male Sprague Dawley rats were used for this study. SBI was induced by partial resection of the right frontal lobe. PLA2 or 0.9% NaCl was injected via rats' tail vein for 3 consecutive days prior to SBI. For mechanism study, a selective PLA2 inhibitor, Manoalide and 5-LOX inhibitor, Zileuton were injected intravenously with PPC to elucidate the role of PLA2 and 5-LOX in PPC-mediated anti-inflammatory effects. Brain water content (BWC) and lung water content, neurological tests, ELISA, western blot, immunohistochemistry, white blood cells (WBC) count, and spectrophotometric assay for intra-operative hemorrhage volume were evaluated. ResultsFirst, PPC reduced brain water content, intra-operative bleeding, and improved neurological function after SBI. Second, PPC decreased 5-LOX expression and brain leukocyte infiltration, while increasing glial fibrillary acidic protein (GFAP) expression in the peri-resection brain tissue after SBI. Third, PPC induced peripheral inflammation represented by mild pulmonary inflammation and increased peripheral blood WBC count and LTB4 level. Lastly, PPC increased blood glucose concentration and glucocorticoid levels after SBI. In addition, PPC mediated above-mentioned changes were partially reversed by administration of PLA2 inhibitor, Manoalide and 5-LOX inhibitor, Zileuton. ConclusionsPPC conferred neuroprotection against SBI via multi-target involvement induced anti-inflammatory mechanisms.

Loss of natural killer T cells promotes pancreatic cancer in LSL-KrasG12D/+ mice.

The role of the unique T-cell population, natural killer T (NKT) cells, which have similar functions to NK cells in pancreatic cancer (PC), is not yet evaluated. To address the regulatory roles of NKT cells on tumour progression through tumour-associated macrophages (TAM) and their production of microsomal prostaglandin E synthase-1 (mPGES-1) and 5-lipoxygenase (5-LOX) in (Kras)-driven pancreatic tumour (KPT) progression, we crossed CD1d-/- mice deficient in both invariant and variant NKT cells with the KrasG12D mice. Loss of NKT cells significantly increased pancreatic intraepithelial neoplasia (PanIN) lesions and also increased 5-LOX and mPGES-1 expression in M2-type macrophages and cancer stem-like cells in pancreatic tumours. Pharmacological inhibition of mPGES-1 and 5-LOX in M2 macrophages with specific inhibitor YS-121 in KPT-CD1d-/- mice decreased PanIN lesions and suppressed tumour growth in association with elevated levels of active CD8a cells. Hence, NKT cells regulate PC by modulating TAMs (M2) through mPGES-1 and 5-LOX; and the absence of NKT cells leads to aggressive development of PC.

5-LOX in Alzheimer's Disease: Potential Serum Marker and In Vitro Evidences for Rescue of Neurotoxicity by Its Inhibitor YWCS.

The inflammatory process plays a key role in neurodegenerative disorder. The inflammatory molecule, 5-lipooxygenase (5-LOX), protein is involved in the pathologic phenotype of Alzheimer's disease (AD) which includes Aβ amyloid deposition and tau hyperphosphorylation. This study determined the level of 5-LOX in serum of AD patients, mild cognitive impairment (MCI) patients, and the normal elderly, and the rescue effect by YWCS, a peptide inhibitor of 5-LOX on neurotoxicity by Aβ amyloid25-35 (Aβ25-35) in neuroblastoma cells. The concentration of serum 5-LOX was estimated by surface plasmon resonance and western blot. The neuroprotective effect of 5-LOX peptide inhibitor YWCS in Aβ25-35-induced neurotoxicity was analyzed by MTT assay and western blotting. We found significant upregulated serum 5-LOX in AD patients and also in MCI patients compared to the normal control group. The peptide inhibitor of 5-LOX, YWCS, prevented the neurotoxic effect of Aβ25-35 by reducing the expression of γ-secretase as well as p-Tau181 in SH-SY5Y cells. However, YWCS was nontoxic towards normal HEK cells. The differential expression of serum 5-LOX among the study groups suggests it can be one of potential serum protein marker and a therapeutic regimen for AD and MCI. The negative correlation with neuropsychological parameters, i.e., MoCA and HMSE, increases its importance and makes it useful during the clinical setup which is very needful in developing countries. Peptide YWCS can serve as a new platform as a 5-LOX inhibitor which can prevent neurotoxicity developed in AD.

Cysteinyl leukotriene receptor 1 facilitates tumorigenesis in a mouse model of colitis-associated colon cancer.

Cysteinyl leukotriene receptor 1 (CysLT1R) has been shown to be up-regulated in the adenocarcinomas of colorectal cancer patients, which is associated with a poor prognosis. In a spontaneous model of colon cancer, CysLT1R disruption was associated with a reduced tumor burden in double-mutant female mice (ApcMin/+/Cysltr1−/−) compared to ApcMin/+ littermates. In the current study, we utilized a genetic approach to investigate the effect of CysLT1R in the induced azoxymethane/dextran sulfate sodium (AOM/DSS) model of colitis-associated colon cancer. We found that AOM/DSS female mice with a global disruption of the Cysltr1 gene (Cysltr1−/−) had a higher relative body weight, a more normal weight/length colon ratio and smaller-sized colonic polyps compared to AOM/DSS wild-type counterparts. The Cysltr1−/− colonic polyps exhibited low-grade dysplasia, while wild-type polyps had an adenoma-like phenotype. The Cysltr1−/− colonic polyps exhibited significant decreases in nuclear β-catenin and COX-2 protein expression, while the normal crypts surrounding the polyps exhibited increased Mucin 2 expression. Furthermore, Cysltr1−/− mice exhibited an overall reduction in inflammation, with a significant decrease in proinflammatory cytokines, polyp 5-LOX expression and infiltration of CD45 leukocytes and F4/80 macrophages. In conclusion, the present genetic approach in an AOM/DSS model further supports an important role for CysLT1R in colon tumorigenesis.

The NF-κB inhibitor celastrol attenuates acute hepatic dysfunction induced by cecal ligation and puncture in rats.

Acute hepatic dysfunction associating sepsis is mediated mainly by toll-like receptor-4 (TLR-4)/nuclear factor kappa-B (NF-κB) inflammatory pathway. This study explores potential hepatoprotective effect of the NF-κB inhibitor celastrol in cecal ligation and puncture (CLP) model in rats. Protective effect of celastrol (1mg/kg, i.p., 1h before CLP) was illustrated after 24h by preventing CLP-induced hepatic histopathological changes and elevation in serum hepatic biomarkers [alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TB) and gamma aminotransferase (γ-GT)] without affecting mortality. Celastrol anti-inflammatory effect was illustrated by inhibiting increased serum and hepatic mRNA expression of interleukin-6 (IL-6) without affecting IL-10 elevation. Furthermore, celastrol inhibited CLP-induced elevations in hepatic mRNA expression of nuclear factor inhibitory protein kappa-B alpha (NFκBia), TLR-4, 5-lipoxygenase (5-LOX) and prevented NF-κB/p65 nuclear translocation and activation. In conclusion, celastrol prevented CLP-induced acute hepatic dysfunction through its anti-inflammatory effect by attenuating NF-κB activation, TLR-4 and 5-LOX expression with subsequent reduction in pro-inflammatory IL-6.

Blockage of cytosolic phospholipase A2 alpha by monoclonal antibody attenuates focal ischemic brain damage in mice

The purposes of the current study were to investigate the effects of a monoclonal antibody (mAb) on cytosolic phospholipase A2 alpha (cPLA2α) in mice with cerebral ischemia-reperfusion (IR) injury and to ascertain the potential mechanisms of those effects. This study evaluated whether the use of anti-cPLA2α mAb could reduce stroke injury in a mouse model of cerebral IR injury. The expression/activity of cPLA2α and cPLA2α- derived proinflammatory lipid mediators such as prostaglandin E2 (PGE2), leukotriene B4 (LTB4), lysophosphatidylcholine (LPC), and free fatty acids (FFA) was assessed. This study also evaluated neurological deficits, motor function, pathological changes, apoptosis, and the area of infarction in the injured mice. Mice treated with anti-cPLA2α mAb recovered neurological function and their condition improved, apoptosis in the brain decreased and infarct volume decreased, and expression of cPLA2α, 5-LOX, COX-2, FFA, LPC, PGE2, and LTB4 was attenuated. Our findings indicate that cPLA2α plays a key role in cerebral IR injury and that treatment with anti-cPLA2α mAb after cerebral IR injury helps to reduce levels of proinflammatory cytokines, alleviate tissue damage, and reduce levels of deleterious lipid mediators. Thus, anti-cPLA2α mAb treatment has the potential to treat ischemic brain damage.

In vivo modulation of LPS induced leukotrienes generation and oxidative stress by sesame lignans

The role of inflammation and oxidative stress is critical during onset of metabolic disorders and this has been sufficiently established in literature. In the present study, we evaluated the effects of sesamol and sesamin, two important bioactive molecules present in sesame oil, on the generation of inflammatory and oxidative stress factors in LPS injected rats. Sesamol and sesamin lowered LPS induced expression of cPLA2 (61 and 56%), 5-LOX (44 and 51%), BLT-1(32 and 35%) and LTC4 synthase (49 and 50%), respectively, in liver homogenate. The diminished serum LTB4 (53 and 64%) and LTC4 (67 and 44%) levels in sesamol and sesamin administered groups, respectively, were found to be concurrent with the observed decrease in the expression of cPLA2 and 5-LOX. The serum levels of TNF-α (29 and 19%), MCP-1 (44 and 57%) and IL-1β (43 and 42%) were found to be reduced in sesamol and sesamin group, respectively, as given in parentheses, compared to LPS group. Sesamol and sesamin offered protection against LPS induced lipid peroxidation in both serum and liver. Sesamol, but not sesamin, significantly restored the loss of catalase and glutathione reductase activity due to LPS (P<.05). However, both sesamol and sesamin reverted SOD activities by 92 and 98%, respectively. Thus, oral supplementation of sesamol and sesamin beneficially modulated the inflammatory and oxidative stress markers, as observed in the present study, in LPS injected rats. Our report further advocates the potential use of sesamol and sesamin as an adjunct therapy wherein, inflammatory and oxidative stress is of major concern.

The lipoxin A4 agonist BML-111 attenuates acute hepatic dysfunction induced by cecal ligation and puncture in rats.

Sepsis is a systemic inflammatory response associating severe infection leading to multi-organ failure, such as hepatic dysfunction. This study investigates the possible hepatoprotective effect of the lipoxin A4 agonist (BML-111) in cecal ligation and puncture (CLP) model in rats. Pretreatment with BML-111 (1mg/kg, i.p., 1h before CLP) protected against CLP-induced mortality after 24h. BML-111 prevented marked inflammatory cells in liver tissues and decreased elevation in serum hepatic biomarkers [alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TB), gamma-glutamyl transferase (γ-GT)] induced by CLP. Additionally, BML-111 attenuated elevated serum level of interleukin-6 (IL-6) and downregulated hepatic IL-6 mRNA expression. Meanwhile, BML-111 further increased serum IL-10 and upregulated hepatic IL-10 mRNA expression, while it downregulated hepatic mRNA expression of nuclear factor inhibitory protein kappa-B alpha (NFκBia), toll-like receptor-4 (TLR-4), and 5-lipooxygenase (5-LOX). Moreover, BML-111 prevented NF-κB/p65 nuclear translocation and activation. In conclusion, BML-111 attenuated CLP-induced acute hepatic dysfunction through its anti-inflammatory effect by decreasing NF-κB activity, TLR-4, and 5-LOX expression with subsequent decrease in pro-inflammatory IL-6 and elevation in anti-inflammatory IL-10.