Macropinocytosis promotes foamy monocyte formation in hypercholesterolemic mice
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ABSTRACT:
PROVIDER: PRJNA1165711 | ENA |
REPOSITORIES: ENA
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Project description:Atherosclerosis-associated vascular disease is the leading cause of death worldwide. Clinical and experimental data demonstrated that circulating monocytes internalize plasma lipoproteins and become lipid-laden foamy cells in hypercholesterolemic subjects. This study was designed to identify the endocytic mechanisms responsible for foamy monocyte formation, perform functional and transcriptomic analysis of foamy and non-foamy monocytes, and characterize specific monocyte subsets in the circulation from normocholesterolemic controls and hypercholesterolemic patients. The presence of foamy monocytes was confirmed in hypercholesterolemic mice and humans via flow cytometry analysis. High resolution scanning electron microscopy (SEM) and quantification of FITC/TRITC-dextran internalization demonstrated macropinocytosis stimulation in human (THP-1) and wild type murine monocytes in vitro. Stimulation of macropinocytosis induced foamy monocyte formation in the presence of unmodified, native LDL (nLDL) and oxidized LDL (ox-LDL) in vitro. Genetic blockade of macropinocytosis (LysMCre+ Nhe1f/f) inhibited foamy monocyte formation in hypercholesterolemic mice in vivo and attenuated monocyte adhesion to atherosclerotic aortas ex vivo. qRT-PCR quantified mRNA levels of major scavenger receptors (SR) in foamy and non-foamy monocytes and identified CD36 as a major SR increasing in response to lipid loading. Deletion of CD36 (Cd36-/-) inhibited foamy monocyte formation in hypercholesterolemic mice. Mechanistic studies identified NADPH oxidase 2 (Nox2)-derived superoxide (O2⋅−) as an important downstream signaling molecule stimulating macropinocytosis in monocytes. Bulk RNA-sequencing characterized transcriptional differences between non-foamy and foamy monocytes and macrophages. Flow cytometry analysis of CD14 and CD16 expression demonstrated a significant increase in intermediate monocytes in hypercholesterolemic patients compared to normocholesterolemic controls. These results provide novel insights into the mechanisms of foamy monocyte formation and potentially identify new therapeutic targets in the treatment of atherosclerosis.
2024-12-26 | GSE278101 | GEO
Project description:Macrophages in atherosclerotic aorta are major population in lesion and contributes to lesion formation by becoming foam cells. To investigate in vivo transcriptome profiles of those macrophages, we extracted foamy and non-foamy macrophages from atherosclerotic aorta using lipid probe-based flow cytometry sorting. Our data indicates that intima non-foamy and foamy macrophages show different mRNA expressions. Rather than non-foamy macrophages, foamy macrophages expressed more genes related to cholesterol metabolism, oxidative phosphorylation, lysosome and so on. The non-foamy macrophages expressed more genes related to immune response (Il-1b related pathways, TNF, TLR signaling pathways) than foamy macrophages.
2018-08-30 | GSE116239 | GEO
Project description:After spinal cord injury (SCI), infiltrating macrophages undergo excessive phagocytosis of myelin and cellular debris, forming lipid-laden foamy macrophages. To understand their role in the cellular pathology of SCI, investigation of foamy macrophage phenotype in vitro revealed a unique inflammatory profile, increased reactive oxygen species (ROS) production, and mitochondrialdysfunction. Bioinformatic analysis identified PI3K as a regulator of inflammation in foamy macrophages, and pharmacological inhibition of this pathway decreased lipid content and inflammatory cytokine and ROS production in these cells. Macrophage-specific inhibition of PI3K using liposomes significantly decreased foamy macrophages at the injury site after a mid-thoracic contusive SCI in mice. RNA sequencing and in vitro analysis of foamy macrophages revealed increased autophagy after PI3K inhibition as a potential mechanism for reduced cellular lipid accumulation. Together, our data suggest that formation of pro-inflammatory foamy macrophages after SCI is due to activation of PI3K signaling that leads to decreased autophagy.
2023-12-05 | GSE237511 | GEO
Project description:Formation of foam cell macrophages (FCMs), which sequester extracellular modified lipids, is a key event in atherosclerosis. How lipid loading affects macrophage phenotype is controversial, with evidence suggesting either pro- or anti-inflammatory consequences. To investigate this further, we compared the transcriptomes of foamy and non-foamy macrophages (NFMs) that accumulate in the subcutaneous granulomas of fed-fat ApoE null mice and normal chow fed wild-type mice in vivo. Consistent with previous studies, LXR/RXR pathway genes were significantly over-represented among the genes up-regulated in foam cell macrophages. Unexpectedly, the hepatic fibrosis pathway, associated with platelet derived growth factor and transforming growth factor-? action, was also over-represented. Several collagen polypeptides and proteoglycan core proteins as well as connective tissue growth factor and fibrosis-related FOS and JUN transcription factors were up-regulated in foam cell macrophages. Increased expression of several of these genes was confirmed at the protein level in foam cell macrophages from subcutaneous granulomas and in atherosclerotic plaques. Moreover, phosphorylation and nuclear translocation of SMAD2, which is downstream of several transforming growth factor-? family members, was also detected in foam cell macrophages. We conclude that foam cell formation in vivo leads to a pro-fibrotic macrophage phenotype, which could contribute to plaque stability, especially in early lesions that have few vascular smooth muscle cells. Samples (n=4/group): Foam cell macrophages (FCM) isolated from inflammatory sponges placed in ApoE null mice fed a high-fat diet (n=4), non-foamy macrophages (NFM) isolated from inflammatory sponges placed in control mice fed a normal diet (n=4).
2015-07-23 | E-GEOD-70126 | biostudies-arrayexpress
Project description:Macropinocytosis has emerged as a nutrient-scavenging pathway that cancer cells exploit to survive the nutrient-deprived conditions of the tumor microenvironment. Cancer cells are especially reliant on glutamine for their survival, and in pancreatic ductal adenocarcinoma (PDAC) cells, glutamine deficiency can enhance the stimulation of macropinocytosis, allowing the cells to escape metabolic stress through the production of extracellular-protein-derived amino acids. Here, we identify the atypical protein kinase C (aPKC) enzymes, PKC and PKCas novel regulators of macropinocytosis. In normal epithelial cells, aPKCs are known to regulate cell polarity in association with the scaffold proteins Par3 and Par6, controlling the function of several targets, including the Par1 kinases. In PDAC cells, we identify that each of these cell polarity proteins are required for glutamine stress-induced macropinocytosis. Mechanistically, we find that the aPKCs are regulated by EGFR signaling or by the transcription factor CREM to promote the relocation of Par3 to microtubules, facilitating macropinocytosis in a dynein-dependent manner. Importantly, we determine that cell fitness impairment caused by aPKC depletion is rescued by the restoration of macropinocytosis and that aPKCs support PDAC growth in vivo. These results identify a previously unappreciated role for cell polarity proteins in the regulation of macropinocytosis and provide a better understanding of the mechanistic underpinnings that control macropinocytic uptake in the context of metabolic stress.
2024-10-22 | GSE276007 | GEO
Project description:Endocrine receptors play an essential role in tumor metabolic reprogramming and represent a potential therapeutic approach in pancreatic ductal adenocarcinoma (PDAC). PDAC is characterized by a nutrient-deprived microenvironment, and to support their energetic needs, they can internalize extracellular proteins via macropinocytosis. In this study, we found that progesterone receptor (PGR), a steroid-responsive nuclear receptor, has a higher expression in PDAC tissues from patients and transgenic LSL-KrasG12D/+; LSL-Trp53R172H/+; PDX1-cre (KPC) mice. Moreover, PGR knockdown restrained PDAC cell survival and tumor growth both in vitro and in vivo. Genetic and pharmacological PGR inhibition resulted in dramatically macropinocytosis impairment in PDAC cells and subcutaneous tumor models, which indicates involvement of this receptor in macropinocytosis regulation. Mechanistically, PGR deficiency caused a subsequently decreased expression of CDC42, a key regulator in macropinocytosis. These data deepen our understanding of how endocrine system influences tumor progression via non-classical pathway and provide a novel therapeutic option for patients with PDAC.
2023-09-27 | GSE228301 | GEO
Project description:Bulk RNA-seq of foamy and non-foamy intimal macrophages from ApoE -/- mouse
| PRJNA477844 | ENA
Project description:The hypocholesterolemic effect of probiotics has been observed, but the molecular mechanism of probiotic-host interaction is still obscure. In this study, DNA microarray technology was used to explore the gene expression profile of liver of hypercholesterolemic rats caused by administration of probiotic Lactobacillus casei Zhang, which can decrease the serum triglyceride, low-density lipoprotein cholesterol, hepatic cholesterol and triglyceride of hypercholesterolemic rats.
2011-12-31 | GSE23740 | GEO
Project description:Statins are efficient in preventing cardiovascular disease progression, but their effects in the absence of low density lipoprotein receptor (LDLR) and on the risk of diabetes are not yet well characterized. The aim was to clarify systemic and pleiotropic effects of Rosuvastatin on cardiovascular and diabetic phenotypes in hypercholesterolemic prediabetic mice. The IGF-II/LDLR-/-ApoB100/100 animals were tested for Rosuvastatin effects on plasma glucose, insulin, lipids, atherosclerosis and liver steatosis. To achieve a more comprehensive view, genes differentially expressed in response to Rosuvastatin were identified by RNA sequencing in liver tissue. Rosuvastatin significantly reduced plasma cholesterol in hypercholesterolemic LDLR – deficient mice, but had no effects on atherosclerosis development at aortic sinus level and in coronary arteries. Rosuvastatin also significantly reduced liver steatosis without any pronounced effects on glucose or insulin levels. RNA sequencing revealed that Rosuvastatin – responsive hepatic genes are involved in cholesterol metabolism and in anti-inflammatory response. In addition, significant changes were detected in the expression of Perilipin 4 and 5 which are involved in lipid droplet formation in the liver. For the first time it was shown that Tribbles proteins are affected by Rosuvastatin treatment in the hypercholesterolemic mice. In conclusion, Rosuvastatin treatment had several positive effects in hypercholesterolemic mice showing early signs of diabetes, and many of these outcomes are unrelated to direct effects on cholesterol and lipoprotein metabolism. These results increase our understanding about the systemic and pleiotropic effects of Rosuvastatin in the absence of LDLR expression.
2018-11-23 | GSE111125 | GEO
Project description:PI3K signaling promotes formation of lipid-laden foamy macrophages at the spinal cord injury site
| PRJNA995560 | ENA