Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2022.12.06.519076

A novel fluorescently-labeled long-chain fatty acid analog for the study of fatty acid metabolism in cultured cells

Hara, Y.·Hirano, K.-i.
View original source ↗Export metadata ↓

Abstract

123I-15-(p-iodophenyl)-(R,S)-methyl pentadecanoic acid (BMIPP) is a long-chain fatty acid (LCFA) analog developed to examine myocardial LCFA metabolism and has been used as a tracer for nuclear cardiology. However, its use is limited because of the specialized features of cardiac scintigraphy. In this study, a novel BMIPP-based probe was utilized, in which iodine-123 was replaced with a fluorescent compound, to extend the use of 123I-BMIPP to a wider variety of cells ex vivo. To confirm that this fluorescent LCFA analog (fluorescent BMPP) was imported into cells, fluorescence-activated cell sorting (FACS) analysis and fluorescent cell imaging were performed using cultured cells. The analysis showed that the import of fluorescent BMPP into the cells occurred in a concentration-dependent manner. This import into cells was inhibited by Sulfosuccinimidyl Oleate in a dose-dependent manner, which is an inhibitor of CD36, a well-known LCFA transporter, suggesting that fluorescent BMPP could be imported into cells via the same pathway as LCFA. FACS and cell imaging intensities of the cells importing fluorescent BMPP were attenuated after incubation in the non-Alexa680-BMPP medium. These results suggest that fluorescent BMPP can be transported into and from cells, reflecting the metabolism of LCFA. Fluorescently-labeled BMPP has the potential to be used as a probe for studying LCFA metabolism in various cells.

Explore related subjects

cell biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Hara, Y., Hirano, K.-i.. 2022-12-08. A novel fluorescently-labeled long-chain fatty acid analog for the study of fatty acid metabolism in cultured cells. https://doi.org/10.1101/2022.12.06.519076

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Functional characterization of Rho GTPase activating proteins SYDE1 and SYDE2

The human genome encodes more than 60 proteins containing Rho GTPase activating protein (RhoGAP) domains, many of which remain understudied with respect to their target specificity and biological roles. SYDE1 and SYDE2 are two such orphan RhoGAPs, for which there are few studies characterizing their biochemical and cellular functions and conflicting reports identifying their cognate GTPases. We previously identified SYDE1 and SYDE2 in a screen for substrates of the c-Jun N-terminal kinases. Here, we show that SYDE1 and SYDE2 are preferentially phosphorylated by JNK1 relative to other mitogen-activated protein kinases (MAPKs) at sites proximal to a kinase docking region. Purified SYDE1 and SYDE2 are shown to have significant catalytic GAP activity toward RhoA, Rac1, and Cdc42. However, neither up- nor down-regulation of SYDE1/2 expression leads to detectable changes in bulk GTP loading of any of these GTPases. Nevertheless, we demonstrate that SYDE1 and SYDE2, in a partially GAP-dependent manner, increase cell spreading and number of focal adhesions, and promote more directionally persistent migration in HEK293 cells. Together, these findings establish SYDE1 and SYDE2 as robust JNK substrates with catalytic activity toward a set of Rho GTPases and reveal basic functions of SYDE1 and SYDE2 in regulating cell morphology, adhesion, and migration.

cell biology↗
bioRxiv2026

The filopodial scaffold polyphosphate dictates cell adhesion-versus-invasion decisions

Inorganic polyphosphate (polyP) is an ancient polymer conserved across all life, serving cell type and location specific functions in every major compartment. Yet its role at the plasma membrane, where it accumulates to peak levels in many primary cells, is largely unknown. Here we identify polyP as a stabilizing component of filopodia, actin based membrane protrusions that govern cell adhesion, contact inhibition, and chemotaxis. Elevating cellular polyP increases filopodial stability and enhances cell adhesion, whereas reducing polyP accelerates filopodial disassembly and promotes cell migration. Mechanistically, we find that polyP acts as a structural filopodial scaffold, recruiting and organizing IRSp53, a membrane curvature inducing protein. We show that metastatic fibroblasts and breast cancer organoids carry markedly reduced and intracellularly reorganized polyP levels relative to their non transformed counterparts. Restoring endogenous polyP via lipid nanoparticle delivery suppresses their invasive phenotypes and reverses prometastatic gene expression signatures, implicating polyP as a primordial tumor suppressor.

cell biology↗
bioRxiv2026

Mitochondrial transfer mediates metabolic communication between beta cells and islet macrophages

Pancreatic islet macrophages support islet homeostasis and adapt their metabolic program in response to environmental cues, including beta cell released factors. Intercellular mitochondrial transfer is a biological process that modulates cellular responses. To test whether beta cells, which are strongly secretory, transfer mitochondria to islet macrophages, we generated mice with beta cell-specific expression of mitochondrial GFP (PhAMfloxIns1Cre). We demonstrate that beta cells transfer mitochondria to islet macrophages in vivo and in vitro. Diabetogenic stressors did not alter the frequency of mitochondrial transfer and macrophages containing beta cell-derived GFP exhibit increased protein synthesis rates. RNA-seq identified upregulation of activity-regulated cytoskeleton associated protein (Arc) in macrophages receiving beta cell-derived mitochondria, while disruption of actin cytoskeleton dynamics prevented mitochondrial transfer. Together, these findings identify mitochondrial transfer as a previously unrecognized mechanism of beta cell-macrophage communication that may contribute to islet homeostasis and immune regulation.

cell biology↗