(346f) Differential Effects of Extracellular Vesicles of Lineage-Specific Human Pluripotent Stem Cells on Cellular Behaviours of Isogenic Cortical Spheroids

Background: Extracellular vesicles (EVs) including exosomes are responsible for a variety of signaling processes and overall physiological and pathological states of stem cells and tissues. Human induced pluripotent stem cells (hiPSCs) have unique characteristics that can mimic embryonic tissue development. EVs derived from hiPSCs can be used as therapeutics, biomarkers, and drug delivery vehicles. One issue is that little is known about the characteristics of secreted EVs/exosomes by hiPSCs and paracrine signaling during tissue morphogenesis and lineage specification.

Method: In this study, the physical and biological properties of EVs isolated from (1) hiPSC-derived neural progenitors (ectoderm), (2) hiPSC-derived cardiac cells (mesoderm), and the undifferentiated hiPSCs, including (3) healthy iPSK3 line and (4) Alzheimer’s disease associated SY-UBH line, were analyzed.

Results: Nanoparticle tracking analysis and electron microscopy results indicate that the derived EVs have the average size of 100-250 nm. Western blot analyses revealed that exosomal markers Alix, CD63, HSC70, and TSG101 were expressed in the derived EVs. MicroRNAs including miR-133, miR-155, miR-221, and miR-34a were differently expressed in different EV groups. Treating the cortical spheroids with different EVs in vitro showed the differential abilities of increasing cell proliferation (indicated by BrdU⁺ cells) and axonal growth (indicated by β-tubulin III staining). For the Aβ42 oligomer treated cultures, the derived EVs increased cell viability and reduced oxidative stress differentially, showing neural protective ability.

Conclusions: Our results demonstrate that the paracrine signaling provided by tissue context-dependent EVs derived from hiPSCs elicit distinct signaling to impact the physiological state of cortical spheroids. This study should advance our understanding of cell-cell communications in stem cell microenvironment and provide possible therapeutic options for treating neural degeneration.

This study was supported by NSF CAREER (1652992) and NIH R03NS102640.