Biology subjects

Collie, S. P.

Publications and source records attributed to Collie, S. P..

3 recordsLinked to original sources

bioRxiv2026

AN OPTIMIZED METHOD TO DIFFERENTIATE HL60 CELLS INTO NEUTROPHIL-LIKE CELLS

The HL60 promyelocytic leukemia cell line is widely used to investigate neutrophil biology due to its genetic tractability and accessibility. HL60 cells can be differentiated into neutrophil-like cells using all-trans retinoic acid (ATRA) or dimethyl sulfoxide (DMSO) treatment. However, these approaches produce cells that lack critical features of mature granulocytes, such as robust chemotaxis with ATRA treatment or multilobed nuclear morphology with DMSO treatment. To overcome these limitations, we developed a sequential differentiation protocol - ATRA for one day followed by DMSO for four days (A1D4) - which yields neutrophil-like cells that more faithfully recapitulate the morphology and functionality of mature human neutrophils. A1D4-differentiated HL60 cells display segmented nuclei with low lamin A/C expression and demonstrate strong chemotactic, oxidative burst, and phagocytic activity. This protocol combines the advantages of individual compounds, producing cells that closely mimic primary neutrophils in both phenotype and function. SUMMARY SENTENCEThe authors provide an improved method to differentiate HL60 cells into neutrophil-like cells that faithfully recapitulates the morphology and functionality of mature human neutrophils.

immunology↗

bioRxiv2025

cPLA2α Targeting to Exosomes Connects Nuclear Deformation to LTB4-Signaling During Neutrophil Chemotaxis

Efficient neutrophil chemotaxis requires the integration of mechanical forces and lipid-mediated signaling. While the signaling lipid leukotriene B4 (LTB4) reinforces cellular polarity, how mechanical cues regulate its production remains unclear. We now show that cytosolic phospholipase A2 (cPLA2), which is essential for the synthesis of LTB4, functions as a nuclear curvosensor. cPLA2 responds to nuclear constrictions by localizing to ceramide-rich inner nuclear membrane microdomains and incorporating onto the exofacial surface of nuclear envelope-derived exosomes. This unique topology enables localized LTB4 synthesis, which promotes myosin light chain II phosphorylation, and sustains polarity and directional persistence after constriction. In neutrophils squeezing through small constrictions, loss of cPLA2 impairs nuclear curvature sensing, exosomal LTB4 production, and post-constriction motility. These findings uncover a cPLA2-dependent mechano-chemical axis linking nuclear architecture to chemotactic efficiency and offering new strategies to modulate inflammatory responses.

cell biology↗

bioRxiv2024

Neutrophils secrete exosome-associated DNA to resolve sterile acute inflammation

Acute inflammation, characterized by a rapid influx of neutrophils, is a protective response that can lead to chronic inflammatory diseases when left unresolved. Secretion of LTB4-containing exosomes is required for effective neutrophil infiltration during inflammation. In this study, we show that neutrophils release nuclear DNA in a non-lytic, rapid, and repetitive manner, via a mechanism distinct from suicidal NET release and cell death. The packaging of nuclear DNA occurs in the lumen of nuclear envelope (NE)-derived multivesicular bodies (MVBs) that harbor the LTB4 synthesizing machinery and is mediated by the lamin B receptor (LBR) and chromatin decondensation. Disruption of secreted exosome-associated DNA (SEAD) in a model of sterile inflammation in mouse skin amplifies and prolongs the presence of neutrophils, impeding the onset of resolution. Together, these findings advance our understanding of neutrophil functions during inflammation and the physiological significance of NETs, with implications for novel treatments for inflammatory disorders.

immunology↗