Macropinocytosis inhibition attenuates pro-fibrotic responses in lung fibroblasts and pulmonary fibrosis
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE300087 | GEO | 2026/04/10
REPOSITORIES: GEO
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Project description:We conducted a bulk RNA sequencing experiment to determine the effect of macropinocytosis inhibitor (5-(N-ethyl-N-isopropyl)-Amiloride, EIPA) in lung fibroblasts
2026-04-10 | GSE298860 | GEO
Project description:Macropinocytosis inhibition attenuates pro-fibrotic responses in lung fibroblasts and pulmonary fibrosis
| PRJNA1278998 | ENA
Project description:Macropinocytosis inhibition attenuates pro-fibrotic responses in lung fibroblasts and pulmonary fibrosis
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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:Pancreatic ductal adenocarcinoma (PDAC) tumors are glutamine-deficient, and both tumor cells and cancer-associated fibroblasts (CAFs) rely on this amino acid to maintain fitness and induce macropinocytosis as an adaptive response. CAFs play a critical role in sculpting the tumor microenvironment, yet how adaptations to metabolic stress impact the stromal architecture remains elusive. In this study, we find that macropinocytosis sustains the myCAF phenotype under glutamine limitation by preventing inflammatory reprogramming. Our data demonstrate that metabolic stress induces an intrinsic inflammatory CAF (iCAF) program through MEK-ERK signaling. We find that blocking macropinocytosis in vivo promotes myCAF-to-iCAF transitions, remodeling the tumor stroma. Importantly, stromal remodeling driven by macropinocytosis inhibition—including iCAF enrichment, collagen reduction, immune cell infiltration, and vascular expansion—sensitizes PDAC tumors to immunotherapy and chemotherapy. Our findings reveal that inhibiting macropinocytosis promotes an inflammatory, less fibrotic tumor microenvironment that can be leveraged to improve therapeutic responses in PDAC.
2025-06-27 | GSE301021 | GEO
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:The uptake of macromolecules and cellular debris through macropinocytosis has emerged as an important nutrient acquisition strategy of cancer cells. Genetic alterations commonly found in human cancers (e.g. mutations in KRAS or loss of PTEN) have been shown to increase macropinocytosis. To identify additional effectors that enable cell growth dependent on the uptake of extracellular proteins, pancreatic ductal adenocarcinoma (PDA) cells were selected for growth in medium where extracellular albumin was the obligate source of the essential amino acid leucine. Analysis of global changes in chromatin availability and gene expression revealed that PDA cells selected under these conditions exhibited elevated activity of the transcriptional activators Yap/Taz. Knockout of Yap/Taz prevented growth of PDA cells in leucine-deficient medium, but not in complete medium. Furthermore, constitutively active forms of Yap or Taz were sufficient to stimulate macropinocytosis of extracellular protein. Together, these studies suggest that the Hippo pathway effectors Yap and Taz are important transcriptional regulators of endocytic nutrient uptake.
2020-09-17 | GSE155674 | GEO
Project description:The uptake of macromolecules and cellular debris through macropinocytosis has emerged as an important nutrient acquisition strategy of cancer cells. Genetic alterations commonly found in human cancers (e.g. mutations in KRAS or loss of PTEN) have been shown to increase macropinocytosis. To identify additional effectors that enable cell growth dependent on the uptake of extracellular proteins, pancreatic ductal adenocarcinoma (PDA) cells were selected for growth in medium where extracellular albumin was the obligate source of the essential amino acid leucine. Analysis of global changes in chromatin availability and gene expression revealed that PDA cells selected under these conditions exhibited elevated activity of the transcriptional activators Yap/Taz. Knockout of Yap/Taz prevented growth of PDA cells in leucine-deficient medium, but not in complete medium. Furthermore, constitutively active forms of Yap or Taz were sufficient to stimulate macropinocytosis of extracellular protein. Together, these studies suggest that the Hippo pathway effectors Yap and Taz are important transcriptional regulators of endocytic nutrient uptake.
2020-09-17 | GSE155650 | GEO
Project description:Although a nonessential amino acid in normal cells, the demand for glutamine is dramatically increased throughout malignant transformation, supporting a range of metabolic processes including mitochondrial ATP production, protein synthesis, purine and pyrimidine biosynthesis. We previously showed that triple-negative breast cancer (TNBC) cells rely on glutamine uptake by the amino acid transporter ASCT2 to sustain their unique glutamine metabolism, thereby supporting in vitro growth and in vivo tumour formation. However, it is known that TNBC cells can also utilise non-transporter mediated nutrient uptake facilitated by processes such as macropinocytosis. We examined proliferation and colony forming ability of human breast cancer cell lines after ASCT2 CRISPR/Cas9 knockout (clonal and polyclonal populations) and shRNA knockdown. Proteomics and mRNAseq analysis further examined cellular and adaptive changes to ASCT2 knockout. Cellular changes were further analysed by western blotting, with macropinocytosis examined using 70kDa dextran-FITC uptake. Metabolic changes were assessed using targeted metabolomics approaches including 13C-labelled substrate tracing and liquid chromatography coupled tandem-mass spectrometry (LC-MS/MS) to determine intracellular levels of key tricarboxylic acid (TCA) cycle intermediates, glycolytic metabolites, fatty acid precursors, nucleotides, and amino acids in human TNBC cell lines in vitro. Despite our previous data showing a significant reduction in cell growth after ASCT2 knockdown, ASCT2 knockout was well-tolerated by both TNBC and Luminal A breast cancer cell lines, with proliferation rates similar to non-targeted CRISPR/Cas9 control cells. This adaptation to knockout was not due to the high glutamine levels present in culture media, as the knockout cells could be cloned in media containing physiological 0.5 mM glutamine. Previous data have shown that TNBC cell lines can undergo constitutive macropinocytosis, and that this could be enhanced when cells are cultured in low nutrient conditions. Indeed, not only did the TNBC cell line HCC1806 undergo constitutive macropinocytosis, the amount of macropinocytosis was significantly enhanced (5-10 fold) in 5 separate ASCT2 knockout clones. By comparison, the ASCT2 knockdown cell line, which have a significant proliferation deficit, showed a modest 2-fold increase in macropinocytosis. Despite in-depth analysis of gene and protein levels by mRNAseq and proteomics, ASCT2 knockout cells did not display a significant alteration in macropinocytic gene expression, but instead showed a substantial upregulation of Ser473-Akt phosphorylation which may drive the adaptive macropinocytosis in TNBC. These data suggest that the constitutive macropinocytosis present in TNBC cell lines provides a novel resistance mechanism to strategies targeting glutamine uptake alone. Despite this adaptation, TNBC cells continue to rely on glutamine, however therapeutic targeting may need to focus on other unique TNBC metabolic pathways such as single-pass glutaminolysis, which couples glutamine and glucose metabolism together.
2024-09-16 | PXD053894 | Pride