Neural stem cells (NSCs) are used to treat various nervous system diseases because of their self-renewal ability and multidirectional differentiation potential. However, an insufficient ability to track their migration in vivo and poor control over their survival and differentiation efficiency are two major critical challenges for clinical application. Here, it is shown that when magnetic nanobubbles (MNBs), which are assembled from magnetic nanoparticles, are internalized by NSCs, intramembrane volumetric oscillation of the MNBs induces an increase in intracellular hydrostatic pressure and cytoskeleton force, resulting in the activation of the Piezo1-Ca 2+ mechanosensory channel. This subsequently triggers the BMP2/Smad biochemical signaling pathway, leading to differentiation of NSCs into the neuronal phenotype. Signaling through the Piezo1-Ca 2+ -BMP2/Smad pathway can be further accelerated by application of an external shear stress force using low-intensity pulsed ultrasound. More importantly, magnetic resonance imaging and ultrasound imaging surveillance of NSCs based on MNB labeling can be leveraged to provide NSC therapeutic outcomes. Both the in vitro and in vivo findings demonstrate that a bubble nanostructure-induced physical force can modulate and control the mechanical signaling pathway regulating stem cell development.
Abstract Modulating intestinal macrophage polarization is critical for maintaining intestinal barrier integrity. Our previous study demonstrated that glucomannan from Aloe vera gel (AGP) improved the intestinal barrier, yet its direct impact on intestinal macrophages remained undefined. Here, we demonstrated that AGP reduced M1 macrophage infiltration in colonic tissue. Integrated serum untargeted metabolomics identified lactic acid as a key AGP-induced metabolite, with 16S rRNA sequencing pointing to the gut microbiota as its potential source. Mechanistically, lactic acid suppressed M1 polarization by inhibiting the mechanosensitive cation channel Piezo1, thereby attenuating calcium influx, concurrently dampening STAT3 activation and ROS production─core drivers of M1 commitment. Critically, these effects were abrogated by a Piezo1 agonist, confirming the centrality of the lactic acid–Piezo1–Ca2+ axis. Collectively, our study defines a novel immunometabolic pathway wherein AGP fortifies the intestinal barrier through microbiota-derived lactic acid, which restrains macrophage M1 polarization via the lactic acid–Piezo1–calcium axis.
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