Placental vesicles may calm chronic inflammation in RDEB, study shows
Study findings may point toward a possible treatment approach
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Tiny packets of cellular cargo called extracellular vesicles (EVs) that are released from placental cells may help calm the chronic inflammation that drives scarring and tissue damage in people with recessive dystrophic epidermolysis bullosa (RDEB), a new study found.
In laboratory experiments, these extracellular vesicles shifted inflammatory immune cells isolated from RDEB patients toward a more balanced, less inflammatory state, suggesting a possible treatment approach to ease disease-related inflammation.
The cell-based study, “Trophoblast Extracellular Vesicles Rewire Immunity: A Symptom-Relief Avenue for Recessive Dystrophic Epidermolysis Bullosa,” was published in the Journal of Extracellular Vesicles.
Could placental vesicles treat inflammatory diseases?
RDEB is caused by mutations in the gene that encodes type VII collagen, a protein that anchors the skin’s layers together. Without this protein, the skin becomes fragile and prone to blistering and wounds. Over time, the ongoing tissue injury triggers chronic inflammation that contributes to progressive scarring and damage that can extend to multiple organs.
Monocytes are immune cells that normally help fight infection and repair tissue. However, when they remain persistently activated, they release inflammatory substances that worsen tissue damage, as seen in people with RDEB. Scientists have been searching for ways to redirect these overactive monocytes toward a more protective, tissue-repairing role.
Trophoblast EVs are released by placental cells that carry biological cargo, such as RNA, proteins, and fat-like lipids, to facilitate communication between the mother and the developing fetus. Evidence suggests they help the mother’s immune system tolerate the genetically distinct fetus without weakening her overall immune responses.
This natural process led researchers to wonder whether placental vesicles could treat inflammatory diseases. Still, finding standardized, scalable sources of EVs from placental tissue has been difficult.
Monocytes from RDEB patients experienced a shift
To address this limitation, the team used a cell line called HIPEC, which mimics extravillous trophoblasts (EVTs), an invasive placental cell type. This cell line provides a consistent, renewable source of vesicles, dubbed EVT-EVs.
The researchers characterized these vesicles, then tested their effects on monocytes from healthy donors and adults with RDEB who harbor different mutations of COL7A1 , the gene responsible for RDEB.
The EVT-EVs carried markers typical of early placental tissue and a cargo enriched in microRNAs, small RNA molecules that regulate protein production. The microRNAs in the vesicles were linked to immune responses, inflammatory signaling, and metabolic pathways.
When healthy donor monocytes were exposed to EVT-EVs, the cells took them up steadily over time, with detectable uptake at 60 minutes and near-complete uptake by eight hours. Analysis of monocyte proteins showed that treatment changed the levels of 334 proteins, reflecting a shift toward a more regulatory and less inflammatory state.
These results highlight EVT-EVs as a versatile platform for advancing both mechanistic insight and next-generation EV-based therapeutics.
Monocytes treated with EVT-EVs showed an increased capacity to engulf and clear particles (phagocytosis). They also produced more of the anti-inflammatory signal protein interleukin-10 and released less pro-inflammatory TNF. Moreover, these monocytes promoted the growth of regulatory T-cells, which help maintain immune balance.
In addition, analysis of fat-like lipids showed that EVT-EV-treated monocytes produced higher levels of molecules associated with the resolution of inflammation.
Monocytes are typically grouped into subsets, including classical cells, which are less inflammatory, and pro-inflammatory intermediate cells. Compared with healthy controls, monocytes from RDEB patients were skewed toward the more inflammatory intermediate subset.
After three days of EVT-EV treatment, this balance shifted back toward the classical, less inflammatory subset. This change in the classical-to-intermediate monocyte ratio was statistically significant, meaning it was unlikely to have occurred by chance.
“These results highlight EVT-EVs as a versatile platform for advancing both mechanistic insight and next-generation EV-based therapeutics,” the researchers concluded.
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