Neuroprotective Effects of Human-Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cell Extracellular Vesicles in Ischemic Stroke Models

Extracellular vesicles of ADSCs inhibit ischemic stroke-induced pyroptosis through Gbp3 regulation: A role for the NLRP3/GSDMD signaling pathway

BACKGROUND

Mounting data indicates that extracellular vesicles (EVs) have the potential to improve the injury after a stroke. Pyroptosis is a recently identified kind of programmed cell death that initiates an inflammatory reaction. We aimed to ascertain the therapeutic implications and possible molecular processes of EVs obtained from adipose-derived stem cells (ADSCs) in inhibiting pyroptosis in ischemic stroke.

METHODS

The investigation employed transient middle cerebral artery occlusion (tMCAO) rat model and a BV2 of oxygen-glucose deprivation/reoxygenation (OGD/R) to ascertain ADSCs-EVs implications on inflammation and pyroptosis as assessed by neurological deficit scores, TTC staining, IHC, HE, CCK8, WB, ELISA, and immunofluorescence. RNA-Seq was performed on BV2 cells in the control, OGD/R, and OGD/R + ADSCs-EVs groups. Using sequencing data analysis, in the OGD/R group, we screened the upregulated genes regulated by EVs, overlapped with 74 pyroptosis-related genes, and identified Guanylate-binding protein 2 (Gbp2) and Guanylate-binding protein 3 (Gbp3) as key genes. Following the validation of the sequencing results in vivo and in vitro, Gbp3 was selected for further study. To test its regulatory effects on inflammation and pyroptosis, Gbp3 was knocked down and overexpressed in vitro.

RESULTS

The administration of ADSCs-EVs resulted in a significant reduction in neurological involvement scores and reduced infarct volume in rats with tMCAO. They were also protective against BV-2 cells after OGD/R. In vivo and in vitro, ADSCs-EVs inhibited inflammatory response and pyroptosis after stroke. The outcomes of the RNA-Seq data analysis manifested that the protective implications of EVs after stroke are mediated by the modulation of inflammation-related mechanisms. Moreover, treatment with EVs led to a significant reduction in Gbp3 expression in post-ischemic brain tissue and cells. When Gbp3 was knocked down, the expression of inflammatory molecules and proteins linked to pyroptosis had a significant decline. When Gbp3 was overexpressed, the opposite results were obtained.

CONCLUSIONS

ADSCs-EVs modulate the NLRP3/GSDMD signaling pathway via Gbp3 to attenuate the inflammatory response and reduce pyroptosis that occurs after stroke.

Mesenchymal stem cell-derived exosomes in renal ischemia-reperfusion injury: a new therapeutic strategy

Renal ischemia-reperfusion injury (RIRI) is a serious kidney condition that causes significant damage due to lack of blood flow. This injury leads to oxidative stress and inflammation, which can cause acute tubular necrosis and kidney failure. Stem cell-derived exosomes, small vesicles released by stem cells, have shown promise in treating RIRI. Mesenchymal stem cells (MSCs) have been used to mitigate RIRI, and their exosomes have been found to play a crucial role in repairing damaged tissues. This review explores the key roles of exosomes from different sources of MSCs in RIRI, the potential of MSC-derived exosomes in treating this disease, and future research directions.

The Role of the Complement System in Synaptic Pruning after Stroke

Stroke is a serious disease that can lead to local neurological dysfunction and cause great harm to the patient's health due to blood cerebral circulation disorder. Synaptic pruning is critical for the normal development of the human brain, which makes the synaptic circuit completer and more efficient by removing redundant synapses. The complement system is considered a key player in synaptic loss and cognitive impairment in neurodegenerative disease. After stroke, the complement system is over-activated, and complement proteins can be labeled on synapses. Microglia and astrocytes can recognize and engulf synapses through corresponding complement receptors. Complement-mediated excessive synaptic pruning can cause post-stroke cognitive impairment (PSCI) and secondary brain damage. This review summarizes the latest progress of complement-mediated synaptic pruning after stroke and the potential mechanisms. Targeting complement-mediated synaptic pruning may be essential for exploring therapeutic strategies for secondary brain injury (SBI) and neurological dysfunction after stroke.

Hollow fiber bioreactor allows sustained production of immortalized mesenchymal stromal cell-derived extracellular vesicles

Aim: Mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) have been reported to hold great potential as cell-free therapies due to their low immunogenicity and minimal toxicity. However, the large doses of MSC-EVs that are required for their clinical application highlight the urgency of finding a large-scale system for MSC-EV manufacture. In this study, we aimed to set up a hollow fiber bioreactor system for the continuous homogenous production of functional and high-quality MSC-EVs. Methods: MSC lines from two donors were immortalized (iMSC) and inoculated into hollow fiber bioreactors. Throughout 4 weeks, conditioned medium was daily harvested. iMSC-EVs were purified and characterized for content, immunophenotype, size, and functionality and compared to 2D cultured iMSC. Results: The iMSC inoculated into the bioreactor remained viable during the whole culture period, and they maintained their MSC phenotype at the end of EV production. Our results showed that the bioreactor system allows to obtain 3D-cultured iMSC-derived EVs (3D-EVs) that are comparable to flask (2D)-cultured iMSC-derived EVs (2D-EVs) in terms of protein and lipid content, size, and phenotype. We also confirm that 3D-derived EVs exhibit comparable functionality to 2D-EVs, showing pro-angiogenic potential in a dose-dependent manner. Conclusions: These findings suggest that setting up a hollow fiber bioreactor system inoculating immortalized MSC lines facilitates the large-scale, functional, and high-quality production of iMSC-EVs. Our results emphasize the great potential of this production methodology to standardize EV production in the pursuit of clinical applications.

Comparative Study of the Protective and Neurotrophic Effects of Neuronal and Glial Progenitor Cells-Derived Conditioned Media in a Model of Glutamate Toxicity In Vitro

Cell therapy represents a promising approach to the treatment of neurological diseases, offering potential benefits not only by cell replacement but also through paracrine secretory activities. However, this approach includes a number of limiting factors, primarily related to safety. The use of conditioned stem cell media can serve as an equivalent to cell therapy while avoiding its disadvantages. The present study was a comparative investigation of the antioxidant, neuroprotective and neurotrophic effects of conditioned media obtained from neuronal and glial progenitor cells (NPC-CM and GPC-CM) on the PC12 cell line in vitro. Neuronal and glial progenitor cells were obtained from iPSCs by directed differentiation using small molecules. GPC-CM reduced apoptosis, ROS levels and increased viability, expressions of the antioxidant response genes HMOX1 and NFE2L2 in a model of glutamate-induced oxidative stress. The neurotrophic effect was evidenced by a change in the morphology of pheochromocytoma cells to a neuron-like phenotype. Moreover, neurite outgrowth, expression of GAP43, TUBB3, MAP2, SYN1 genes and increased levels of the corresponding MAP2 and TUBB3 proteins. Treatment with NPC-CM showed moderate antiapoptotic effects and improved cell viability. This study demonstrated the potential application of CM in the field of regenerative medicine.