LDL Cholesterol Uptake Assay Using Live Cell Imaging Analysis with Cell Health Monitoring

Ritter, Portia; Yousefi, Keyvan; Ramirez, Juliana; Dykxhoorn, Derek M.; Mendez, Armando J.

doi:10.3791/58564-v

Cited by 4 publications

(1 citation statement)

References 27 publications

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“…Using multiphoton intravital microscopy of these orthotopic pancreatic tumors, we traced the rate of cancer cell uptake of intravenously injected LDL particles containing BODIPY-conjugated cholesterol [19] (green). As the 25 nm-sized LDL particles rapidly enter the blood vessels and permeate to the interstitial fluid, the uptake of LDL by the cells within the pancreatic tumor mass becomes visible only as large intracellular endosomes, containing BODIPY-cholesterol, accumulate [20] (Fig. 1a, 1b and Supplementary video 1).…”

Section: Resultsmentioning

confidence: 99%

Trogocytosis of cancer-associated fibroblasts promotes pancreatic cancer growth and immune suppression via phospholipid scramblase anoctamin 6 (ANO6)

Ogier,

Solomon,

et al. 2023

Preprint

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In pancreatic ductal adenocarcinoma (PDAC), the fibroblastic stroma constitutes most of the tumor mass and is remarkably devoid of functional blood vessels. This raises an unresolved question of how PDAC cells obtain essential metabolites and water-insoluble lipids. We have found a critical role for cancer-associated fibroblasts (CAFs) in obtaining and transferring lipids from blood-borne particles to PDAC cells via trogocytosis of CAF plasma membranes. We have also determined that CAF-expressed phospholipid scramblase anoctamin 6 (ANO6) is an essential CAF trogocytosis regulator required to promote PDAC cell survival. During trogocytosis, cancer cells and CAFs form synapse-like plasma membranes contacts that induce cytosolic calcium influx in CAFs via Orai channels. This influx activates ANO6 and results in phosphatidylserine exposure on CAF plasma membrane initiating trogocytosis and transfer of membrane lipids, including cholesterol, to PDAC cells. Importantly, ANO6-dependent trogocytosis also supports the immunosuppressive function of pancreatic CAFs towards cytotoxic T cells by promoting transfer of excessive amounts of cholesterol. Further, blockade of ANO6 antagonizes tumor growth via disruption of delivery of exogenous cholesterol to cancer cells and reverses immune suppression suggesting a potential new strategy for PDAC therapy.

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Section: Resultsmentioning

confidence: 99%

Trogocytosis of cancer-associated fibroblasts promotes pancreatic cancer growth and immune suppression via phospholipid scramblase anoctamin 6 (ANO6)

Ogier,

Solomon,

et al. 2023

Preprint

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Human ovarian granulosa cells use clathrin-mediated endocytosis for LDL uptake: immunocytochemical and electron microscopic study

Abdulova

Purelku

ŞAHİN

et al. 2023

Ultrastructural Pathology

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βPix sequesters IDOL and prevents LDL receptor degradation through a β₂AR-regulated signaling pathway in Alport Syndrome

Chahdi

Yousefi

Capcha

et al. 2020

Preprint

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Alport syndrome (AS) is a rare disease of the glomerular basement membrane type IV collagen causing progressive renal failure. We reported increased accumulation of low-density lipoprotein (LDL) receptor (LDLR) and subsequent LDL cholesterol (LDL-C) uptake in renal tubular epithelial cells (TEC) in Alport mice, but the mechanisms regulating LDLR stability and function remain unknown. Here, we show that a selective β2-Adrenoceptor (β2AR) agonist, salbutamol, decreased LDLR levels and LDL-C uptake in Alport kidneys accompanied with reduced albuminuria and improved cardiac systolic and diastolic function. Similarly, salbutamol decreased LDL-C uptake in HK2 and HEK293 human renal epithelial cell lines, in smooth muscle cells from an X-linked hereditary nephropathy dog model (a large animal model of AS), and in TECs differentiated from AS patient-derived iPSCs. We show that the Rac1/Cdc42 guanine nucleotide exchange factor β1Pix blocked β2AR-induced LDLR degradation and, hence, increased LDL-C uptake. β1Pix also abrogated ubiquitination and degradation of LDLR induced by the inducible degrader of the LDLR (IDOL), an E3 ubiquitin ligase that promotes lysosomal LDLR ubiquitination and degradation. We identify a multimolecular complex comprised of βPix, IDOL, and LDLR and demonstrate that βPix counteracts β2AR-mediated LDLR degradation by sequestering IDOL. Our findings show βPix acts as a significant post-transcriptional regulator of IDOL-mediated LDLR degradation and identify β2AR activation as a potential treatment for Alport pathology.

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LDL Cholesterol Uptake Assay Using Live Cell Imaging Analysis with Cell Health Monitoring

Cited by 4 publications

References 27 publications

Trogocytosis of cancer-associated fibroblasts promotes pancreatic cancer growth and immune suppression via phospholipid scramblase anoctamin 6 (ANO6)

Trogocytosis of cancer-associated fibroblasts promotes pancreatic cancer growth and immune suppression via phospholipid scramblase anoctamin 6 (ANO6)

Human ovarian granulosa cells use clathrin-mediated endocytosis for LDL uptake: immunocytochemical and electron microscopic study

βPix sequesters IDOL and prevents LDL receptor degradation through a β₂AR-regulated signaling pathway in Alport Syndrome

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LDL Cholesterol Uptake Assay Using Live Cell Imaging Analysis with Cell Health Monitoring

Cited by 4 publications

References 27 publications

Trogocytosis of cancer-associated fibroblasts promotes pancreatic cancer growth and immune suppression via phospholipid scramblase anoctamin 6 (ANO6)

Trogocytosis of cancer-associated fibroblasts promotes pancreatic cancer growth and immune suppression via phospholipid scramblase anoctamin 6 (ANO6)

Human ovarian granulosa cells use clathrin-mediated endocytosis for LDL uptake: immunocytochemical and electron microscopic study

βPix sequesters IDOL and prevents LDL receptor degradation through a β2AR-regulated signaling pathway in Alport Syndrome

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Product

Resources

About

βPix sequesters IDOL and prevents LDL receptor degradation through a β₂AR-regulated signaling pathway in Alport Syndrome