| Background:Accumulated evidence suggests that the crosstalk between dendritic cells (DCs) and natural killer (NK) cells enhances each other's capacity, and results in the production of a variety of soluble factors. However, little is known about the effect of DC-NK crosstalk in interleukin-23(IL-23) production. Angiotensin II (Ang II), the major bioactive peptide of the renin-angiotensin system (RAS), plays a critical role in regulating cardiovascular homeostasis. The data accumulated from studies in humans and animals have revealed that Ang â…¡ plays a key role in leading the development of atherosclerosis. However, no previous work has examined the effect of DC-NK cell crosstalk on IL-23production. Furthermore, the effect of Ang â…¡ on DC-NK crosstalk is unknown.Objective:We undertook our present work to explore whether IL-23was produced in the DC-NK cell coculture system, in the absence or presence of Ang â…¡, and elucidated the underlying mechanisms involved in this process. Methods:Bone marrow-derived dendritic cells (BMDCs) and NK cells were were generated from C57BL/6mice Mouse, dendritic cells cocultured with NK cells in the absence or presence of angiotensin â…¡. The cytokine IL-23in supernatants from cell cultures were measured with ELISA kit. The maturation status of DCs was evaluated by flow cytometry. The total and phosphorylation levels of ERK1/2, p38, JNK1/2/3were determined in total protein extracts by Western blot. DCs were pretreated with PD98059, SB203580, or SP600125prior to coculture with NK cells or Ang â…¡, to examine the effects of MAPK inhibitors.Results:1) DC-NK coculture caused a high expression of IL-23, angiotensin â…¡ (Ang â…¡) alone moderately increased IL-23production in DCs, but decreased IL-23secretion in the DC-NK coculture system.2) Ang â…¡ does not influence DC maturation in DC-NK crosstalk.3) Ang â…¡ increased IL-23production through the extracellular signal-related kinase (ERK) pathway. All three MAPK members c-Jun N-terminal kinase (JNK), ERK and p38were involved in IL-23production in the DC-NK coculture system. In the presence of Ang â…¡, only the JNK pathway seems to play a role in IL-23production in DCs cocultured with NK.Conclusions:This work demonstrates for the first time that IL-23is produced in the DC-NK coculture system, and that Ang â…¡ is involved in DC-NK crosstalk. These data suggest that distinct MAPK pathways are involved in IL-23production in DCs in response to different stimuli. BackgroundDendritic cells (DCs) and their stimulation by oxidized low-density lipoprotein (oxLDL) are critical to the development of atherosclerosis. MicroRNAs play important roles in cell proliferation, apoptosis and differentiation that accompany inflammatory responses. In our previously study, we found the miR-29a expression was increased in oxLDL-stimulated DCs. Whether and how inflammatory cytokine and chemokine production in DCs were regulated by miR-29a, need to be investigated.ObjectivesThe aim of the present study was to investigate the effect of miR-29a on DCs function and detenmain the target gene of miR-29a.MethodsDCs were cultured from human primary peripheral blood. DCs were transfected with microRNA-29a mimics or inhibitors. Inflammatory cytokine and chemokine in the cell culture supernatants were analyzed by ELISA. Real time quantitative PCR and Western blot were analyzed to detenmain the HSPA14expression. To determine the target gene of miR-29a, the293T cells were cotransfected with HSPA143'-UTR luciferase reporter vector and miR-29a mimic or inhibitor.ResultsWe showed that miR-29a plays an important role in proinflammatory cytokine IL-12secretion and chemokine CCL3and CCL5expression upon oxLDL-treatment. HSPA14is the target gene of miR-29a. High expression of miR-29a decreased HSPA14gean both in mRNA and protein level.ConclusionsMicroRNA-29a down-regulates pro-inflammatory cytokine secretion and chemokine expression by targeting HSPA14in oxLDL-stimulated dendritic cells.
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