Human umbilical cord mesenchymal stem cells-derived exosomes restore lung architecture and reduce the susceptibility to asthma of offspring in maternal asthma

Asthma is a heterogeneous disorder driven by inflammatory processes that promote pathogenic airway remodeling. Human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Exos) emerge as a compelling therapeutic candidate to disrupt this disease cycle, with potential intergenerational benefits. In a chronic OVA-induced asthma model using C57BL/6 mice, hucMSC-Exos were delivered via serial injections during the sensitization phase. Airway structural changes were evaluated through histological analysis (H&E staining, Masson's trichrome) and immunofluorescence for key remodeling markers including α-SMA, CC-10, and the proliferation marker Ki67. Molecular pathway analyses specifically targeted the TGF-β/Smad and STAT6 signaling cascades. We found that hucMSC-Exos intervention effectively ameliorated the core pathological features of asthma-induced lung injury and significantly reduced the levels of IL-6 and TNF-α in bronchoalveolar lavage fluid (BALF) in a dose-dependent manner. Additionally, this treatment reduced asthma susceptibility in offspring of mothers with chronic asthma. Compared to the OVA group, the Exos group showed restored CC-10 expression and decreased pulmonary Ki67 levels. In offspring, Hopx (but not SPC) expression was significantly elevated at PN1 and PN4 relative to the OVA group, though these differences lost statistical significance at PN14, consistent with Western blotting (WB) validation. Notably, unlike maternal findings, both CC-10 and Ki67 expression in the lungs of treated offspring were lower than in controls. Furthermore, we observed that OVA-induced activation of PECAM-1, α-SMA, p-ROCK1, and Caspase-8 was attenuated by hucMSC-Exos treatment. RNA sequencing of hucMSC-Exos identified asthma-associated miRNAs, including let7a-5p and miR-125a-5p. The therapeutic efficacy of hucMSC-Exos against asthma was partially abolished when these miRNA inhibitors were applied, underscoring their critical regulatory role in exosome-based asthma therapy. In conclusion, hucMSC-Exos have demonstrated significant efficacy in the treatment of asthma, capable of alleviating airway remodeling and related symptoms. What is particularly important is that they have a cross-generational protective effect, which can reduce the asthma susceptibility of children born to asthmatic mothers. Mechanistically, this benefit may be achieved through the transfer of asthma-related miRNAs. These findings elucidate the key molecular pathways of the cross-generational therapeutic effect mediated by hucMSC-Exos, providing a scientific basis for their clinical application in the management of maternal and offspring asthma.