Deciphering the regulatory mechanisms of extracellular particle-mediated signaling

Cells release extracellular particles (EPs) to establish non-contact intercellular communication. EPs are packaged with biomolecules reflective of the donor cell’s status (referred to as signals) and can traverse the extracellular space to transfer these signals to neighboring or distant target cells. This EP-mediated signaling is recognized as critical for maintaining homeostasis and for disease progression, especially within the immune system, central nervous system, and tumor microenvironment. Additionally, EP-based therapeutic tools, such as drug delivery vessels, and the use of EPs for biopsy, are considered to have high potential. However, the precise regulatory mechanisms underlying EP-mediated intercellular signaling remain unclear, largely due to the heterogeneity within EPs. EPs can range in size from 30 nm to 1000 nm and may contain a variety of biomolecules, including lipids, proteins, nucleic acids, and metabolites. The specific content of individual EPs depends on multiple factors, such as their biogenesis pathways and donor cell type and status. Analyzing this heterogeneity in situ during signaling events is technically challenging, therefore, it is not clear how cells regulate the heterogeneous profile of EPs to achieve specificity during intercellular signaling. The PI’s lab uses quantitative fluorescence microscopy and spectroscopy to investigate molecular information processing at the biointerface, including the assembly and activity of biomolecules at the liquid-liquid interface, as well as imaging-based diagnostic assays with single-EP arrays. The objective of this research program is to elucidate the mechanism of EP-mediated intercellular signaling by deciphering the roles of distinct EP subtypes at the single-particle level, from their release by donor cells to their transport across intercellular physical barriers and interactions with recipient cells. The rationale of this proposal is that uncovering such fundamentals is essential for understanding EP’s biological roles under both physiological and pathological conditions. Over the next five years, the PI’s lab will address three outstanding, currently intractable questions: Q1: How are signals from the donor cell translated into the profiles of released EPs? Q2: How do EPs traverse extracellular barriers to reach recipient cells? Q3: How do the recipient cells interpret the profiles of incoming EPs? The PI and her team will address these questions through a combination of biointerface engineering, microscopy and spectroscopy, and molecular biology techniques. A network of collaborations supports this program. The impact of this project is to provide (1) opportunities for advancing EP-based therapeutic tools and diagnostic assays by improving understanding of the specificity and sensitivity in EP biology; (2) much needed techniques to investigate a variety of functional extracellular bioparticles, including synaptic vesicles and lipoproteins. Project Number: 1R35GM162491-01 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of General Medical Sciences (NIGMS) | Principal Investigator: Simou Sun | Institution: STATE UNIVERSITY NEW YORK STONY BROOK, STONY BROOK, NY | Award Amount: $432,569 | Activity Code: R35 | Study Section: Maximizing Investigators' Research Award C Study Section[MRAC] View on NIH RePORTER: https://reporter.nih.gov/project-details/11272390