taurochenodeoxycholic-acid and acetovanillone

Obesity involves inflammation. MCP-1, an inflammatory chemokine, and MCP-1-induced protein (MCPIP) are known to induce adipogenesis that causes increase in the number of adipocytes. Here we elucidate the intermediate processes through which MCPIP induces adipogenesis. Forced expression of MCPIP in 3T3-L1 preadipocytes caused increased reactive oxygen/nitrogen species (ROS/RNS) production and inducible-nitric oxide synthase (iNOS) expression, endoplasmic reticulum stress (ER), as indicated by expression of ER chaperones and protein disulfide isomerase, and autophagy as indicated by expression of beclin-1 and cleavage of LC3. Treatment of ROS inhibitor, apocynin attenuated MCPIP induction of adipogenesis as measured by the induction of transcription factors involved in adipogenesis, adipocyte markers and lipid droplet accumulation. Inhibition of ER stress with taurursodeoxycholate or knockdown of inositol requiring enzyme 1 (IRE1) inhibited MCPIP induced autophagy and adipogenesis. Preadipocytes in adipogenesis-inducing cocktail manifested ER stress and autophagy. Knockdown of MCPIP attenuated these effects. MCPIP induced p38 activation and p38 inhibitor, SB203580, attenuated MCPIP-induced adipogenesis.

Topics: 3T3-L1 Cells; Acetophenones; Adipogenesis; Animals; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Endoplasmic Reticulum Chaperone BiP; Endoplasmic Reticulum Stress; Endoribonucleases; Heat-Shock Proteins; Imidazoles; Mice; Nitric Oxide Synthase Type II; Obesity; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Protein Serine-Threonine Kinases; Pyridines; Reactive Nitrogen Species; Reactive Oxygen Species; Ribonucleases; RNA Interference; RNA, Small Interfering; Taurochenodeoxycholic Acid

Major diseases such as cardiovascular diseases, rheumatoid arthritis, diabetes, obesity and tumor growth are known to involve inflammation. Inflammatory molecules such as MCP-1, TNF-α, IL-1β and IL-8 are known to promote angiogenesis. MCP-induced protein (MCPIP), originally discovered as a novel zinc finger protein induced by MCP-1, is also induced by other inflammatory agents. MCPIP was shown to mediate MCP-1-induced angiogenesis. Whether angiogenesis induced by other inflammatory agents is mediated via MCPIP is unknown and the molecular mechanisms involved in angiogenesis induced by MCPIP have not been elucidated. The aim of this study was to bridge this gap and delineate the sequential processes involved in angiogenesis mediated via MCPIP. siRNA knockdown of MCPIP was used to determine whether different inflammatory agents, MCP-1, TNF-α, IL-1β and IL-8, mediate angiogenesis via MCPIP in human umbilical vein endothelial cells (HUVECs). Chemical inhibitors and specific gene knockdown approach were used to inhibit each process postulated. Oxidative stress was inhibited by apocynin or cerium oxide nanoparticles or knockdown of NADPH oxidase subunit, phox47. Endoplasmic reticulum (ER) stress was blocked by tauroursodeoxycholate or knockdown of ER stress signaling protein IRE-1 and autophagy was inhibited by the use of 3'methyl adenine, or LY 294002 or by specific knockdown of beclin1. Matrigel assay was used as a tool to study angiogenic differentiation induced by inflammatory agents or MCPIP overexpression in HUVECs. Tube formation induced by inflammatory agents, TNF-α, IL-1β, IL-8 and MCP-1 was inhibited by knockdown of MCPIP. Forced MCPIP-expression induced oxidative stress, ER stress, autophagy and angiogenic differentiation in HUVECs. Inhibition of each step caused inhibition of each subsequent step postulated. The results reveal that angiogenesis induced by inflammatory agents is mediated via induction of MCPIP that causes oxidative and nitrosative stress resulting in ER stress leading to autophagy required for angiogenesis. The sequence of events suggested to be involved in inflammatory angiogenesis by MCPIP could serve as possible targets for therapeutic intervention of angiogenesis-related disorders.

Topics: Acetophenones; Anti-Inflammatory Agents, Non-Steroidal; Antiviral Agents; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Chemokine CCL2; Chromones; Endoplasmic Reticulum Stress; Endoribonucleases; Human Umbilical Vein Endothelial Cells; Humans; Interleukin-1beta; Interleukin-8; Membrane Proteins; Morpholines; Neovascularization, Physiologic; Oxidative Stress; Protein Serine-Threonine Kinases; Reactive Oxygen Species; Ribonucleases; RNA Interference; RNA, Small Interfering; Taurochenodeoxycholic Acid; Transcription Factors; Tumor Necrosis Factor-alpha