Project description:Background: Atherosclerosis leads high mortality, highlighting an urgent need for new therapeutic strategies. Protein kinases orchestrate multiple cellular events in atherosclerosis and may provide new therapeutic targets for atherosclerosis. Here, we identified a protein kinase, WEE1 G2 checkpoint kinase (WEE1), promoting inflammatory response in atherosclerosis. Methods: The ApoE-/- mice without macrophage-specific WEE1 deletion (ApoE-/-WEE1f/f) and ApoE-/- mice with macrophage-specific WEE1 deletion (ApoE-/-WEE1MCKO) were generated using bone marrow transplantation. These mice and WEE1 inhibitor MK1775 were used in a high-fat diet (HFD)-induced atherosclerotic model. Human atherosclerotic tissues, mouse primary peritoneal macrophages (MPMs), 293T cells, and recombinant proteins were utilized to investigate the pathogenic role and underlying mechanisms of WEE1. Results: We identified up-regulated p-WEE1 in macrophages in atherosclerotic lesions of HFD-fed ApoE-/- mice. Transcriptome sequencing analysis indicated that WEE1 promotes oxLDL-induced inflammation in macrophages. We then demonstrated that macrophage-specific deletion or pharmacological inhibition of WEE1 attenuates atherosclerosis by reducing inflammation both in vivo and in vitro. The overexpression of wild-type WEE1 or activating-mutant WEE1, but not inactivating-mutant WEE1, exacerbates inflammation in macrophages. Mechanistically, transcriptome sequencing analysis and co-immunoprecipitation followed by quantitative proteomics analysis identified p65 as a binding protein of WEE1. We confirmed that WEE1 directly interacts with the RHD domain of p65 via kinase domain and phosphorylates p65 at S536, thereby facilitating subsequent NF-κB activation and inflammatory response in macrophages. Conclusions: Our findings demonstrated that macrophage WEE1 promotes inflammatory atherosclerosis by directly binding to p65 and phosphorylate it at S536. This study provides WEE1 as a new p65 regulator in inflammation and a potential therapeutic target for atherosclerosis.

Project description:Macrophages are key immune cells for the initiation and development of atherosclerotic lesions. However, the macrophage regulatory nodes that determine how lesions progress in response to dietary challenges are not fully understood. Liver X receptors (LXRs) are sterol-regulated transcription factors that play a central role in atherosclerosis by integrating cholesterol homeostasis and immunity. LXR pharmacological activation elicits a robust antiatherosclerotic transcriptional program in macrophages that can be affected by LXRα S196 phosphorylation in vitro. To investigate the impact of these transcriptional changes in atherosclerosis development, we have generated mice carrying a Ser-to-Ala mutation in myeloid cells in the LDL receptor (LDLR)-deficient atherosclerotic background (M-S196ALdlr-KO). M-S196ALdlr-KO mice fed a high-fat diet exhibit increased atherosclerotic plaque burden and lesions with smaller necrotic cores and thinner fibrous caps. These diet-induced phenotypic changes are consistent with a reprogramed macrophage transcriptome promoted by LXRα-S196A during atherosclerosis development. Remarkably, expression of several proliferation-promoting factors, including the protooncogene FoxM1 and its targets, is induced by LXRα-S196A. This is consistent with increased proliferation of plaque-resident cells in M-S196ALdlr-KO mice. Moreover, disrupted LXRα phosphorylation increases expression of phagocytic molecules, resulting in increased apoptotic cell removal by macrophages, explaining the reduced necrotic cores. Finally, the macrophage transcriptome promoted by LXRα-S196A under dietary perturbation is markedly distinct from that revealed by LXR ligand activation, highlighting the singularity of this posttranslational modification. Overall, our findings demonstrate that LXRα phosphorylation at S196 is an important determinant of atherosclerotic plaque development through selective changes in gene transcription that affect multiple pathways.

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Macrophage DCLK1 promotes atherosclerosis via binding to IKKβ and inducing inflammatory responses

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