13-hydroperoxy-9-11-octadecadienoic-acid and Inflammation

It is well known that consumption of a high-fat diet (HFD) promotes intestinal inflammation despite little being known about causative factors. Recent evidence implicates dietary peroxidized lipids (POLs), which are typically formed from the oxidation of polyunsaturated fatty acid double bonds, as potential contributors due to their enrichment in HFDs, ability to be formed during gastrointestinal transit, and immunogenic and cytotoxic properties. 13-HPODE, the most common dietary POL, demonstrates pro-inflammatory activity in a variety of immune cells, especially Natural Killer (NK) cells whose role in mediating intestinal inflammation remains unclear. Therefore, we set out to investigate how 13-HPODE and other POLs modulate NK-cell activity in the context of intestinal inflammation. We not only found that NK cells fully decompose exogenous 13-HPODE, but that direct treatment stimulates TNF-α and MCP1 expression as well as Granzyme B (GZMB) secretion in a dose-dependent manner. Similar results were observed upon incubation of NK cells with oxidized, but not-unoxidized, low-density lipoproteins. Secretory products from 13-HPODE-treated NK cells were able to induce Caco2 intestinal cell inflammation in the same way as exogenous GZMB with greater sensitivity in undifferentiated compared to differentiated cells. Results were recapitulated in 13-HPODE-fed mice, demonstrating both spatial and temporal patterns of elevated GZMB expression that favored acute treatments in the distal intestinal epithelium. Collectively, our results suggest that that HFD-derived POLs, like 13-HPODE, potentially contribute to intestinal inflammation by stimulating the secretion of pro-inflammatory granzymes by resident NK cells, ultimately revealing a more direct role for diet in modulating gut homeostasis and the immune environment.

Topics: Animals; Caco-2 Cells; Dietary Fats; Granzymes; Humans; Inflammation; Intestinal Diseases; Intestinal Mucosa; Killer Cells, Natural; Linoleic Acids; Lipid Peroxides; Male; Mice; Mice, Inbred C57BL

Inflammation is an essential host response during bacterial infections such as bovine mastitis. Endothelial cells are critical for an appropriate inflammatory response and loss of vascular barrier integrity is implicated in the pathogenesis of

Topics: Acetylcysteine; Animals; Apoptosis; Cattle; Cells, Cultured; Endothelial Cells; Humans; Inflammation; Leukocytes, Mononuclear; Linoleic Acids; Lipid Peroxides; Mammary Glands, Human; Oxylipins; Streptococcus

The leukocyte- type 12/15-Lipoxygenase (12/15-LO) enzyme and its oxidized lipid products play important roles in vascular smooth muscle cell (VSMC) growth, migration, and matrix responses associated with hypertension, atherosclerosis, and restenosis. However, much less is known about their inflammatory effects. In this study, we showed that the 12/15-LO product of linoleic acid, 13-hydroperoxyocta decadienoic acid (13-HPODE) can transcriptionally upregulate the expression of the chemokine monocyte chemoattractant protein-1 (MCP-1) in VSMC. We also observed reduced activation of the transcription factor, NF-kappa B and reduced expression of MCP-1/JE mRNA in VSMC from 12/15-LO knock-out mice relative to WT. To confirm the role of NF-kappa B in 13-HPODE-induced MCP-1 expression and to selectively block the induction of such inflammatory genes in VSMC, we designed novel molecular approaches to knockdown NF-kappa B with short interfering RNAs (siRNAs). We designed siRNAs to human NF-kappa B p65 transcriptionally active subunit by using a rapid PCR-based approach that generates sense and antisense siRNA separated by a hairpin loop downstream of the U6 promoter. siRNA PCR products targeting seven different sites on p65 cDNA could induce upto 92% reduction in HA-p65 protein levels. A six-fold decrease in NF-kappa B-dependent luciferase activity was also seen. Transfection of human VSMC with these siRNA PCR products resulted in 70% reduction in p65 protein levels. We cloned the PCR products into a pCR3.1 vector and these p65 siRNA expressing plasmids very effectively blocked 13-HPODE-induced expression of both MCP-1 and TNF-alpha genes. These results show for the first time that 13-HPODE can induce MCP-1 in the vasculature via activation of NF-kappa B.

Topics: Animals; Base Sequence; Cell Line; Cells, Cultured; Chemokine CCL2; Cloning, Molecular; Down-Regulation; Gene Expression Regulation; Genetic Vectors; Humans; Immunoblotting; Inflammation; Linoleic Acids; Lipid Metabolism; Lipid Peroxides; Luciferases; Mice; Mice, Knockout; Microscopy, Fluorescence; Molecular Sequence Data; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; NF-kappa B; Oligonucleotides; Oligonucleotides, Antisense; Plasmids; Polymerase Chain Reaction; Promoter Regions, Genetic; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; RNA, Messenger; RNA, Small Interfering; Sequence Homology, Nucleic Acid; Time Factors; Transcription, Genetic; Transfection; Up-Regulation