Intranasal Human NSC-Derived EVs Therapy Can Restrain Inflammatory Microglial Transcriptome, and NLRP3 and cGAS-STING...

Area of Science:

• Neuroscience
• Immunology
• Gerontology

Background:

• Neuroinflammaging, characterized by chronic hippocampal inflammation, drives age-related cognitive decline.
• This inflammation involves nucleotide-binding domain, leucine-rich repeat family, and pyrin domain-containing 3 (NLRP3) inflammasomes and the cGAS-STING-IFN-1 pathway.
• Extracellular vesicles from human induced pluripotent stem cell-derived neural stem cells (hiPSC-NSC-EVs) possess therapeutic miRNAs that can mitigate neuroinflammation.

Purpose of the Study:

• To investigate the therapeutic potential of intranasal hiPSC-NSC-EVs in mitigating neuroinflammaging in aged mice.
• To determine the effects of hiPSC-NSC-EVs on hippocampal inflammation, oxidative stress, and related signaling pathways.
• To identify specific miRNAs within hiPSC-NSC-EVs responsible for inhibiting key inflammatory pathways.

Main Methods:

• Administration of intranasal hiPSC-NSC-EVs to late middle-aged mice (18 months old) and assessment at 20.5 months.
• Analysis of hippocampal tissue for astrocyte hypertrophy, microglial activation, oxidative stress markers, and protein/gene expression.
• In vitro assays with RAW cells and single-cell RNA sequencing of microglia to elucidate miRNA mechanisms and transcriptomic changes.

Main Results:

• hiPSC-NSC-EVs treatment reduced hippocampal astrocyte hypertrophy, microglial clusters, and oxidative stress.
• Therapy decreased NLRP3 inflammasome, p38 MAPK, cGAS-STING-IFN-1, and JAK-STAT signaling pathway activation.
• miRNA-30e-3p and miRNA-181a-5p within hiPSC-NSC-EVs were identified as key inhibitors of NLRP3 and STING pathways, respectively.
• Single-cell RNA sequencing revealed hiPSC-NSC-EVs modulated microglial transcriptomes, enhancing oxidative phosphorylation and reducing pro-inflammatory gene expression.
• These molecular changes correlated with improved cognitive and memory function in treated mice.

Conclusions:

• Intranasal hiPSC-NSC-EVs effectively reduce neuroinflammaging in the aged hippocampus.
• The therapy diminishes pro-inflammatory microglial signaling cascades, promoting better brain function in aging.
• hiPSC-NSC-EVs represent a promising therapeutic strategy for age-related cognitive decline.