In older mice, a treatment using tiny particles derived from stem cells, delivered through the nose, reduces specific inflammatory structures in brain immune cells that are linked to...
Mechanism
Synthesis from 1 study
Stem cell bubbles delivered through the nose calm down overactive brain immune cells by delivering tiny molecules that shut down key inflammation switches. This stops the immune cells from clustering abnormally and releasing harmful chemicals, helping the brain return to a healthier state.
Most probable mechanism
Tiny bubbles from stem cells, sprayed into the nose, travel to the brain and get absorbed by immune cells there. These bubbles carry a special molecule that blocks the production of a key protein needed to turn on a dangerous inflammatory switch inside the immune cells. Without this switch, the immune cells don't release harmful chemicals, stop clustering abnormally, and return to a calmer state.
hiPSC-NSC-EVs are taken up by microglia in the hippocampus after intranasal delivery
miR-30e-3p from the extracellular vesicles enters microglial cytoplasm and binds to the 3' untranslated region of NLRP3 mRNA
Binding of miR-30e-3p to NLRP3 mRNA suppresses translation of NLRP3 protein
Reduced NLRP3 protein impairs assembly of the NLRP3-ASC-caspase-1 inflammasome complex
Failure of inflammasome assembly prevents caspase-1 activation and maturation of IL-1β and IL-18
Suppression of NLRP3 inflammasome activity reduces formation of disease-associated microglial clusters
Less supported by current evidence, but not ruled out
The same stem cell bubbles also carry another molecule that blocks a different alarm system in immune cells, preventing them from releasing interferons that keep inflammation going. This helps calm the immune cells and stop them from forming abnormal clusters.
hiPSC-NSC-EVs are taken up by microglia in the hippocampus after intranasal delivery
miR-181a-5p from the extracellular vesicles enters microglial cytoplasm and binds to the coding sequence of STING mRNA
Binding of miR-181a-5p to STING mRNA suppresses translation of STING protein
Reduced STING protein impairs oligomerization and activation of the cGAS-STING pathway
Impaired STING signaling prevents TBK1 and IRF3 phosphorylation and reduces IFN-α production
Reduced interferon signaling diminishes JAK-STAT activation and expression of interferon-stimulated genes in microglia
Suppression of cGAS-STING signaling contributes to reduced microglial cluster formation and inflammatory phenotype
The stem cell bubbles change the genetic instructions inside immune cells, turning down genes that cause inflammation and turning up genes that help cells produce energy and stay healthy. This shift makes the immune cells less reactive and less likely to form harmful clusters.
hiPSC-NSC-EVs are internalized by microglia in the hippocampus
EV cargo modulates transcriptional regulators and signaling pathways in microglia
Proinflammatory gene networks (TLR, MAPK, TNF, IL-17, NOD-like) are suppressed
Metabolic and homeostatic gene networks (oxidative phosphorylation, cholesterol metabolism) are enhanced
Transcriptional reprogramming reduces microglial activation and disease-associated cluster formation
Shifted microglial phenotype reduces neurotoxic cytokine release and oxidative stress
Evidence from Studies
Supporting (1)
Community contributions welcome
Intranasal Human NSC‐Derived EVs Therapy Can Restrain Inflammatory Microglial Transcriptome, and NLRP3 and cGAS‐STING Signalling, in Aged Hippocampus
Contradicting (0)
Community contributions welcome
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.