geranylgeranyl-pyrophosphate and Inflammation

Mevalonate kinase deficiency is a rare autosomal recessive inborn error of metabolism with an autoinflammatory phenotype. In this review we discuss its pathogenesis, clinical presentation and treatment. Mutations in both copies of the MVK-gene lead to a block in the mevalonate pathway. Interleukin-1beta mediates the inflammatory phenotype. Shortage of a non-sterol isoprenoid product of the mevalonate pathway, Geranylgeranylpyrophosphate leads to aberrant activation of the small GTPase Rac1, and inflammasome activation. The clinical phenotype ranges widely, depending on the severity of the enzyme defect. All patients show recurrent fevers, lymphadenopathy and high acute phase proteins. Severely affected patients have antenatal disease onset, dysmorphic features, growth retardation, cognitive impairment and progressive ataxia. Diagnosis relies on mutation analysis of the MVK-gene. There is no evidence based therapy. IL-1 blockade is usually effective. Severe cases require allogeneic stem cell transplantation. Targeted therapies are needed.

Topics: Enzyme Activation; Humans; Inflammasomes; Inflammation; Interleukin-1beta; Mevalonate Kinase Deficiency; Mevalonic Acid; Phosphotransferases (Alcohol Group Acceptor); Polyisoprenyl Phosphates; rac1 GTP-Binding Protein; Rare Diseases

Acute lung injury (ALI) is a critical illness syndrome with high morbidity and mortality in patients. Inflammation has been known to be involved in the development of ALI. The purpose of this study was to investigate the effect of puerarin on lipopolysaccharide (LPS)-induced ALI in mice. The pro-inflammatory cytokines TNF-α, IL-6 and IL-1β were determined by ELISA. Western blot analysis was used for detecting the expression of NF-κB, IκBα, and LXRα. And myeloperoxidase (MPO) activity, lung wet/dry (W/D) ratio, and histopathological examination were also detected in lung tissues. The results showed that puerarin significantly inhibited LPS-stimulated MPO activity in lung tissues. Meanwhile, puerarin attenuated lung histopathological changes and lung wet/dry (W/D) ratio. We also found that the expression of pro-inflammatory cytokines, TNF-α, IL-6 and IL-1β were inhibited by puerarin. Puerarin also inhibited LPS-induced TNF-α in RAW264.7 cells and IL-8 in A549 cells. From the results of western blotting, puerarin significantly suppressed LPS-stimulated NF-κB activation. And the expression of LXRα was dose-dependently increased by treatment of puerarin. The inhibition of puerarin on TNF-α production in RAW264.7 cells and IL-8 production in A549 cells were blocked by LXRα inhibitor geranylgeranyl pyrophosphate (GGPP). These results suggested that puerarin attenuated ALI by activating LXRα, which subsequently inhibited LPS-induced inflammatory response.

Topics: A549 Cells; Acute Lung Injury; Animals; Cytokines; Humans; Inflammation; Interleukin-1beta; Interleukin-6; Interleukin-8; Isoflavones; Lipopolysaccharides; Liver X Receptors; Lung; Mice; Mice, Inbred BALB C; NF-kappa B; NF-KappaB Inhibitor alpha; Peroxidase; Polyisoprenyl Phosphates; RAW 264.7 Cells; Tumor Necrosis Factor-alpha

Lysophosphatidic acid (LPA) is a bioactive lipid that acts via at least six G protein-coupled receptors, LPA receptors 1-6 (LPA1-6), for various physiological functions. We examined (1) whether LPA5 is involved in pain signaling in the spinal cord; and (2) the pharmacological effects of a novel LPA5 antagonist on intrathecal prostaglandin (PG)- and (S)-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-induced allodynia, and neuropathic and inflammatory pain in rodents. Intrathecal injection of a selective LPA5 agonist, geranylgeranyl diphosphate, and a non-selective agonist, LPA, induced allodynia in wild type, but not in LPA5 knockout mice. These novel results suggest that LPA5 is important for pain signal transmission in the spinal cord. AS2717638 (6,7-dimethoxy-2-(5-methyl-1,2-benzoxazol-3-yl)-4-(piperidin-1-ylcarbonyl)isoquinolin-1(2H)-one) bound to the LPA-binding site on LPA5 and selectively inhibited LPA-induced cyclic adenosine monophosphate accumulation in human LPA5-but not LPA1-, 2-, or 3-expressing cells. Further, oral administration of AS2717638 inhibited LPA5 agonist-induced allodynia in mice. AS2717638 also significantly improved PGE

Topics: Analgesics; Animals; Benzoxazoles; Cells, Cultured; Cyclic AMP; Female; Hyperalgesia; Inflammation; Injections, Spinal; Isoquinolines; Lysophospholipids; Male; Mice, Inbred C57BL; Mice, Knockout; Neuralgia; Pain; Pain Threshold; Piperidines; Polyisoprenyl Phosphates; Rats, Inbred Lew; Rats, Sprague-Dawley; Receptors, Lysophosphatidic Acid

It has been proposed that high-density lipoprotein (HDL) loses its cardioprotective ability through oxidative modifications by reactive oxygen species (ROS) and promote atherogenesis. However, the pro-atherogenic pathways undergone by oxidized HDL remain poorly understood. Since monocytes play a crucial role in atherogenesis, this study was aimed to investigate the influence of both native and oxidized HDL (oxHDL) on monocytes-macrophages functions relevant to atherogenesis. HDL particles were isolated from human blood samples by ultracentrifugation and subjected to in vitro oxidation with CuSO(4). The extent of oxidation was quantitated by measurement of lipid peroxides. Human peripheral blood mononuclear cells were isolated and cultured under standard conditions. Cells were treated with native and oxHDL at varying concentrations for different time intervals and used for several analyses. Intracellular ROS production was assessed based on ROS-mediated DCFH fluorescence of the cells. The release of TNF-α and matrix metalloproteinases (MMPs) was quantitated using ELISA kit and gelatine zymography, respectively. Treatment of cells with oxidized HDL enhanced the production of ROS in a concentration-dependent way, while native HDL had no such effect. Further, the release of TNF-α, MMP-9, and MMP-2 was found to be remarkably higher in cells incubated with oxHDL than that of native HDL. Results demonstrate that oxidative modification of HDL induces pro-inflammatory response and oxidative stress in human monocytes-macrophages.

Topics: Atherosclerosis; Cell Death; Cell Survival; Cells, Cultured; Humans; Inflammation; Inflammation Mediators; Lipid Metabolism; Lipoproteins, HDL; Liver X Receptors; Macrophages; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Monocytes; Orphan Nuclear Receptors; Oxidation-Reduction; Oxidative Stress; Polyisoprenyl Phosphates; Reactive Oxygen Species; Tumor Necrosis Factor-alpha

Panax notoginseng (Burk.) F.H. Chen has been used as a health product and natural remedy in traditional medicine for cardiovascular diseases for more than 1000 years in Asia, including China, Japan, and Korea. Panax notoginseng saponins (PNS) are the major effective ingredients extracted from Panax notoginseng.. The purpose of this study was to investigate whether Panax notoginseng saponins (PNS) attenuated atherosclerosis by inducing liver X receptor alpha (LXRα) expression and to elucidate the mechanisms responsible for the effects.. The AS rats were treated once daily with PNS (100 mg/kg, i.p.), and pathological changes in the aorta were observed using Sudan IV staining. The expression of LXRα in the aortic wall was measured by Western blot analysis. THP-1 macrophages were cultured with PNS in the presence or absence of geranylgeranyl pyrophosphate ammonium salt (GGPP), an LXRα antagonist. The expression of LXRα and its target genes ATP-binding cassette A1 and G1 (ABCA1, ABCG1) were determined by qRT-PCR. The transcriptional activation of the LXRα gene promoter was analyzed by a reporter assay. The NF-κB DNA binding activity and the expression of interleukin (IL)-6, monocyte chemotactic protein-1 (MCP-1) was evaluated respectively by Trans-AM NF-κB ELISA and ELISA in THP-1 macrophages that were stimulated with LPS after treatment with PNS and GGPP.. PNS treatment alleviated the typical pathological changes associated with atherosclerosis in rats. The expression of LXRα was increased in rat aortas after treatment with PNS. In vitro, PNS increased LXRα mRNA levels in THP-1 macrophages. The reporter assays showed that PNS enhanced transcriptional activation of the LXRα gene promoter and led to the upregulation of ABCA1 and ABCG1 expression. This upregulation could be reversed by treatment with GGPP. Additionally, PNS inhibited NF-κB DNA binding activity and reduced secretion of IL-6 and MCP-1 in LPS-stimulated THP-1 macrophages. These effects could be reversed by GGPP.. The results indicated that the PNS-mediated attenuation of AS may, at least partly, due to LXRα uprergulation. The mechanisms of action included enhancement transcriptional activation of the LXRα gene promoter by PNS and subsequent upregulation of ABCA1 and ABCG1 and inhibition of NF-κB DNA binding activity.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Aorta; Atherosclerosis; ATP Binding Cassette Transporter 1; ATP Binding Cassette Transporter, Subfamily G, Member 1; ATP-Binding Cassette Transporters; Cell Line; Humans; Inflammation; Lipid Metabolism; Liver X Receptors; Macrophages; Male; NF-kappa B; Orphan Nuclear Receptors; Panax notoginseng; Phytotherapy; Polyisoprenyl Phosphates; Rats; Rats, Wistar; RNA, Messenger; Saponins

The effects of HMG-CoA reductase inhibitors on C-reactive protein (CRP)-induced pro-inflammatory changes in endothelial cells remain unclear. We tested the hypothesis that simvastatin inhibited CRP-induced pro-inflammatory changes in endothelial cells by decreasing mevalonate pathway products.. Human umbilical vein endothelial cells were incubated with CRP and measurement of CD32, nuclear factor kappaB (NF-kappaB) activation, vascular cell adhesion molecule-1 expression and monocyte adhesion assay were performed. The effects of simvastatin, siRNA against CD32 (siCD32) and mevalonate pathway products were also examined.. Pre-treatment with simvastatin significantly attenuated the CRP-induced CD32 expression and NF-kappaB activation in human umbilical vein endothelial cells. Simvastatin also decreased CRP-induced vascular cell adhesion molecule-1 expression and reduced monocyte adhesion on endothelial cells. The inhibitory effects of simvastatin were significantly reversed by adding mevalonate and geranylgeranyl pyrophosphate (GGPP), but not by adding farnesyl pyrophosphate. Pre-treatment with siCD32 also decreased CRP-induced CD32 expression and inhibitor of kappaB degradation. However, neither mevalonate nor GGPP reversed the effects of siCD32.. CRP-induced CD32 expression and NF-kappaB activation were attenuated by simvastatin. A decrease in mevalonate and subsequent GGPP contributes to the inhibitory effects of simvastatin. These findings may provide an explanation of using statins on patients with high serum CRP levels.

Topics: C-Reactive Protein; Cell Adhesion; Cells, Cultured; Endothelium, Vascular; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inflammation; Mevalonic Acid; Monocytes; NF-kappa B; Polyisoprenyl Phosphates; Receptors, IgG; RNA, Small Interfering; Sesquiterpenes; Simvastatin; Umbilical Veins; Up-Regulation; Vascular Cell Adhesion Molecule-1

Impaired remyelination is critical to neuroinflammation in multiple sclerosis (MS), which causes chronic and relapsing neurological impairments. Recent studies revealed that immunomodulatory activity of statins in an experimental autoimmune encephalomyelitis (EAE) model of MS are via depletion of isoprenoids (farnesyl-pyrophosphate and geranylgeranyl-pyrophosphate) rather than cholesterol in immune cells. In addition, we previously documented that lovastatin impedes demyelination and promotes myelin repair in treated EAE animals. To this end, we revealed the underlying mechanism of lovastatin-induced myelin repair in EAE using in vitro and in vivo approaches. Survival, proliferation (chondroitin sulfate proteoglycan-NG2(+) and late oligodendrocyte progenitor marker(+)), and terminal-differentiation (myelin basic protein(+)) of OPs was significantly increased in association with induction of a promyelinating milieu by lovastatin in mixed glial cultures stimulated with proinflammatory cytokines. Lovastatin-induced effects were reversed by cotreatment with mevalonolactone or geranylgeranyl-pyrophosphate, but not by farnesyl-pyrophosphate or cholesterol, suggesting that depletion of geranygeranyl-pyrophosphate is more critical than farnesyl-pyrophosphate in glial cells. These effects of lovastatin were mimicked by inhibitors of geranylgeranyl-transferase (geranylgeranyl transferase inhibitor-298) and downstream effectors {i.e., Rho-family functions (C3-exoenzyme) and Rho kinase [Y27632 (N-(4-pyridyl)-4-(1-aminoethyl)cyclohexanecarboxamide dihydrochloride)]} but not by an inhibitor of farnesyl-transferase (farnesyl transferase inhibitor-277). Moreover, activities of Rho/Ras family GTPases were reduced by lovastatin in glial cells. Corresponding with these findings, EAE animals exhibiting demyelination (on peak clinical day; clinical scores >/=3.0) when treated with lovastatin and aforementioned agents validated these in vitro findings. Together, these data provide unprecedented evidence that-like immune cells-geranylgeranyl-pyrophosphate depletion and thus inhibition of Rho family functions in glial cells by lovastatin promotes myelin repair in ameliorating EAE.

Topics: Animals; Benzamides; Cell Differentiation; Cell Proliferation; Cells, Cultured; Cholesterol; Encephalomyelitis, Autoimmune, Experimental; Female; Hydroxymethylglutaryl CoA Reductases; Inflammation; Lovastatin; Methionine; Mevalonic Acid; Myelin Sheath; Nerve Growth Factors; Neuroglia; Oligodendroglia; Polyisoprenyl Phosphates; ras Proteins; Rats; Rats, Inbred Lew; Rats, Sprague-Dawley; rho GTP-Binding Proteins; Spinal Cord; Wound Healing

Rho guanosine triphosphatases (GTPases) orchestrate signaling pathways leading to cell migration. They are typically responsible for the organization of actin filaments that support actomyosin contractility and cell-body translocation. The function of Rho GTPases depends on GTP-loading and isoprenylation by geranylgeranyl pyrophosphate (GGpp). The latter posttranslational modification may be manipulated by agents such as 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors (HMGCRIs) that prevent de novo synthesis of isoprenoids such as GGpp. HMGCRIs have anti-inflammatory properties and substantially reduce infiltration of inflammatory immune cells into target tissues, including the central nervous system (CNS) during neuroinflammation. The depletion of the cellular isoprenoid pool is believed to result in the regulation of antigen-specific T cells outside the target organ and also to prevent migration of these cells into target organs, such as the CNS. In vivo treatment with HMGCRI in the experimental autoimmune encephalitis (EAE) rodent model of multiple sclerosis reduces the capacity of activated T cells to traffic to and within the brain. This presentation shows that geranylgeranylation is fundamental for RhoA-mediated downstream events such as influencing cytoskeletal organization and the migration of T cells. Tethering of RhoA to the membrane by GGpp is necessary for T cell migration and provides a mechanism by which HMGCRI may prevent T cell infiltration into inflamed compartments.

Topics: Animals; Brain; Cell Membrane; Cell Movement; Cytoskeleton; Encephalomyelitis, Autoimmune, Experimental; Guanosine Triphosphate; Hydroxymethylglutaryl CoA Reductases; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inflammation; Lymphocyte Activation; Mice; Multiple Sclerosis; Polyisoprenyl Phosphates; Protein Prenylation; rho GTP-Binding Proteins; rhoA GTP-Binding Protein; T-Lymphocytes

Although lipid-lowering therapy with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) decreases the progression of coronary artery and aortic valve calcification, the mechanism of action of these drugs to inhibit the calcification process remains unclear. In this study, we investigated the effect of statins such as cerivastatin and atorvastatin on vascular calcification by utilizing an in vitro model of inflammatory vascular calcification. Cerivastatin and atorvastatin dose-dependently inhibited in vitro calcification of human vascular smooth muscle cells (HVSMCs) induced by the following inflammatory mediators (IM): interferon-gamma, 1alpha,25-dihydroxyvitamin D3, tumor necrosis factor-alpha, and oncostatin M. These statins also depressed expression of alkaline phosphatase (ALP) in HVSMCs induced by these factors. Mevalonate and geranylgeranylpyrophosphate reversed the inhibitory effect of cerivastatin on ALP expression in HVSMCs, while farnesylpyrophosphate showed no effect on the ALP activities inhibited by this drug, suggesting that inhibition of Rho and its downstream target, Rho kinase may mediate the inhibitory effect of cerivastatin. Cerivastatin prevented RhoA activation in HVSMCs induced by the IM. A specific inhibitor of Rho kinase (Y-27632) inhibited in vitro calcification and induction of ALP in HVSMCs. These findings provide a possible mechanism of statins to prevent the progression of calcification in inflammatory vascular diseases such as atherosclerosis and cardiac valvular calcification.

Topics: Alkaline Phosphatase; Atorvastatin; Calcinosis; Dose-Response Relationship, Drug; Heptanoic Acids; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inflammation; Mevalonic Acid; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Polyisoprenyl Phosphates; Pyridines; Pyrroles; Sesquiterpenes