Project description:Sepsis is a potentially life-threatening condition caused by the body's response to a severe infection. However, the pathogenesis of sepsis remains unclear. Here, we found that Suppressor of Fused (Sufu), a classical negative regulator of Hedgehog signaling, is downregulated in patients with sepsis and in murine peritoneal macrophages treated with lipopolysaccharide (LPS). Deletion of Sufu aggravated LPS-induced lung injury and lethality in mice, and augmented LPS induced proinflammatory gene expression in cultured macrophages. By RNA-seq transcriptome profiling, we identified Sufu as a negative regulator of the TLR-triggered inflammatory response.
Project description:Atherosclerosis is a chronic inflammatory disease with high morbidity and mortality rates worldwide. Doublecortin-like kinase 1 (DCLK1), a microtubule-associated protein kinase, is involved in neurogenesis and human cancers. However, the role of DCLK1 in atherosclerosis remains undefined. In this study, we identified up-regulated DCLK1 in macrophages in atherosclerotic lesions of ApoE-/- mice fed an HFD and determined that macrophage-specific DCLK1 deletion attenuates atherosclerosis by reducing inflammation in mice. Mechanistically, RNA sequencing analysis indicated that DCLK1 mediates oxLDL-induced inflammation via NF-κB signaling pathway in primary macrophages. Co-immunoprecipitation followed by LC-MS/MS analysis identified IKKβ as a binding protein of DCLK1. We confirmed that DCLK1 directly interacts with IKKβ and phosphorylates IKKβ at S177/181, thereby facilitating subsequent NF-κB activation and inflammatory gene expression in macrophages. Finally, a pharmacological inhibitor of DCLK1 prevents atherosclerotic progression and inflammation both in vitro and in vivo. Our findings demonstrated that macrophage DCLK1 promotes inflammatory atherosclerosis by binding to IKKβ and activating IKKβ/NF-κB. This study reports DCLK1 as a new IKKβ regulator in inflammation and a potential therapeutic target for inflammatory atherosclerosis.
Project description:Recent studies have identified intracellular metabolism as a fundamental determinant of macrophage function. In obesity, proinflammatory macrophages accumulate in adipose tissue and trigger chronic low-grade inflammation, that promotes the development of systemic insulin resistance, yet changes in their intracellular energy metabolism are currently unknown. We therefore set out to study metabolic signatures of adipose tissue macrophages (ATMs) in lean and obese conditions. F4/80-positive ATMs were isolated from obese vs lean mice. High-fat feeding of wild-type mice and myeloid-specific Hif1α-/- mice was used to examine the role of hypoxia-inducible factor-1α (HIF-1α) in ATMs part of obese adipose tissue. In vitro, bone marrow-derived macrophages were co-cultured with adipose tissue explants to examine adipose tissue-induced changes in macrophage phenotypes. Transcriptome analysis, real-time flux measurements, ELISA and several other approaches were used to determine the metabolic signatures and inflammatory status of macrophages. In addition, various metabolic routes were inhibited to determine their relevance for cytokine production. Transcriptome analysis and extracellular flux measurements of mouse ATMs revealed unique metabolic rewiring in obesity characterised by both increased glycolysis and oxidative phosphorylation. Similar metabolic activation of CD14+ cells in obese individuals was associated with diabetes outcome. These changes were not observed in peritoneal macrophages from obese vs lean mice and did not resemble metabolic rewiring in M1-primed macrophages. Instead, metabolic activation of macrophages was dose-dependently induced by a set of adipose tissue-derived factors that could not be reduced to leptin or lactate. Using metabolic inhibitors, we identified various metabolic routes, including fatty acid oxidation, glycolysis and glutaminolysis, that contributed to cytokine release by ATMs in lean adipose tissue. Glycolysis appeared to be the main contributor to the proinflammatory trait of macrophages in obese adipose tissue. HIF-1α, a key regulator of glycolysis, nonetheless appeared to play no critical role in proinflammatory activation of ATMs during early stages of obesity. Our results reveal unique metabolic activation of ATMs in obesity that promotes inflammatory cytokine release. Further understanding of metabolic programming in ATMs will most likely lead to novel therapeutic targets to curtail inflammatory responses in obesity.
Project description:Transcriptional profiling to identify genes differentially regulated by Sufu during cerebellum development. Sufu was specifically deleted from the granule neuron compartment using Math1-driven Cre recombinase.
Project description:Osteonecrosis (ON) of the femoral head (ONFH) is a devastating bone disease affecting over 20 million people worldwide. ONFH is caused by a disruption of blood supply, leading to necrotic cell death and increased inflammation. Macrophages are the key cells mediating the inflamma-tory responses in ON. It is unclear what are the dynamic phenotypes of macrophages, and what mechanisms may affect macrophage polarization and therefore the healing process. In our pre-liminary study, we found that there is an invasion of macrophages in the repair tissue during ON healing. Interestingly, in both ONFH patient and the mouse ON model, fat was co-labeled within macrophages using immunofluorescence staining, indicating phagocytosis of fat by mac-rophages. To study the effects of fat phagocytosis on macrophage phenotype, we set up an in vitro macrophage and fat co-culture system. We found that fat phagocytosis significantly de-creased M1 markers expression such as IL1β and iNOS in macrophages. Whereas the expression of M2 marker Arg1 was significantly increased with fat phagocytosis. To investigate if the polar-ization change is indeed mediated by phagocytosis, we treated the cells with Latrunculin A (LA, a phagocytosis inhibitor). LA supplement significantly reversed the polarization marker gene changes induced by fat phagocytosis. To provide an unbiased transcriptional gene analysis, we submitted the RNA for bulk RNA sequencing. Differential gene expression (DGE) analysis re-vealed top up-regulated genes were related to anti-inflammatory responses, while pro-inflammatory genes were significantly downregulated. Additionally, using the pathway en-richment and network analyses (Metascape), we confirmed that gene enriched categories related to pro-inflammatory responses were significantly downregulated in macrophages with fat phagocytosis. Finally, we validated the similar macrophage phenotype changes in vivo. To sum-marize, we discovered that fat phagocytosis occurs in both ONFH patients and the mouse ON model, which inhibits pro-inflammatory responses with increased anabolic gene expressions of macrophages. This fat phagocytosis induced macrophage phenotype is consistent with the in vivo changes shown in the ON mice model. Our study reveals a novel phagocytosis mediated macro-phage polarization mechanism in ON, which fills in our knowledge gaps of macrophage func-tions and provides new concepts in macrophage immunomodulation as a promising treatment for ON.
Project description:Atherosclerosis is a chronic inflammatory disease with high morbidity and mortality rates worldwide. Doublecortin-like kinase 1 (DCLK1), a microtubule-associated protein kinase, is involved in neurogenesis and human cancers. However, the role of DCLK1 in atherosclerosis remains undefined. In this study, we identified up-regulated DCLK1 in macrophages in atherosclerotic lesions of ApoE-/- mice fed an HFD and determined that macrophage-specific DCLK1 deletion attenuates atherosclerosis by reducing inflammation in mice. Mechanistically, RNA sequencing analysis indicated that DCLK1 mediates oxLDL-induced inflammation via NF-κB signaling pathway in primary macrophages. Co-immunoprecipitation followed by LC-MS/MS analysis identified IKKβ as a binding protein of DCLK1. We confirmed that DCLK1 directly interacts with IKKβ and phosphorylates IKKβ at S177/181, thereby facilitating subsequent NF-κB activation and inflammatory gene expression in macrophages. Finally, a pharmacological inhibitor of DCLK1 prevents atherosclerotic progression and inflammation both in vitro and in vivo. Our findings demonstrated that macrophage DCLK1 promotes inflammatory atherosclerosis by binding to IKKβ and activating IKKβ/NF-κB. This study reports DCLK1 as a new IKKβ regulator in inflammation and a potential therapeutic target for inflammatory atherosclerosis.
Project description:SUFU is a negative regulator of the hedgehog signaling pathway and its abnormal expression has been found in several human cancers, whereas the role of SUFU in the malignant development of breast cancer has not been fully elucidated. We performed RNA-seq to determine the impact of SUFU overexpression and knockdown on global gene expression profile in SKBR3 and HCC1954 cells. Our results show that sufu affects ferroptosis phenotype via modulating yap-dependent ACSL4 in breast cancer cells.