Pretreated MSCs with IronQ Transplantation Attenuate Microglia Neuroinflammation via the cGAS-STING Signaling Pathway

Background

Intracerebral hemorrhage (ICH), a devastating form of stroke, is characterized by elevated morbidity and mortality rates. Neuroinflammation is a common occurrence following ICH. Mesenchymal stem cells (MSCs) have exhibited potential in treating brain diseases due to their anti-inflammatory properties. However, the therapeutic efficacy of MSCs is limited by the intense inflammatory response at the transplantation site in ICH. Hence, enhancing the function of transplanted MSCs holds considerable promise as a therapeutic strategy for ICH. Notably, the iron-quercetin complex (IronQ), a metal-quercetin complex synthesized through coordination chemistry, has garnered significant attention for its biomedical applications. In our previous studies, we have observed that IronQ exerts stimulatory effects on cell growth, notably enhancing the survival and viability of peripheral blood mononuclear cells (PBMCs) and MSCs. This study aimed to evaluate the effects of pretreated MSCs with IronQ on neuroinflammation and elucidate its underlying mechanisms.

Methods

The ICH mice were induced by injecting the collagenase I solution into the right brain caudate nucleus. After 24 hours, the ICH mice were randomly divided into four subgroups, the model group (Model), quercetin group (Quercetin), MSCs group (MSCs), and pretreated MSCs with IronQ group (MSCs+IronQ). Neurological deficits were re-evaluated on day 3, and brain samples were collected for further analysis. TUNEL staining was performed to assess cell DNA damage, and the protein expression levels of inflammatory factors and the cGAS-STING signaling pathway were investigated and analyzed.

Results

Pretreated MSCs with IronQ effectively mitigate neurological deficits and reduce neuronal inflammation by modulating the microglial polarization. Moreover, the pretreated MSCs with IronQ suppress the protein expression levels of the cGAS-STING signaling pathway.

Conclusion

These findings suggest that pretreated MSCs with IronQ demonstrate a synergistic effect in alleviating neuroinflammation, thereby improving neurological function, which is achieved through the inhibition of the cGAS-STING signaling pathway.

Mesenchymal stem cells transplantation combined with IronQ attenuates ICH-induced inflammation response via Mincle/syk signaling pathway

BACKGROUND

Intracerebral hemorrhage (ICH) is a severe brain-injured disease accompanied by cerebral edema, inflammation, and subsequent neurological deficits. Mesenchymal stem cells (MSCs) transplantation has been used as a neuroprotective therapy in nervous system diseases because of its anti-inflammatory effect. Nevertheless, the biological characteristics of transplanted MSCs, including the survival rate, viability, and effectiveness, are restricted because of the severe inflammatory response after ICH. Therefore, improving the survival and viability of MSCs will provide a hopeful therapeutic efficacy for ICH. Notably, the biomedical applications of coordination chemistry-mediated metal-quercetin complex have been verified positively and studied extensively, including growth-promoting and imaging probes. Previous studies have shown that the iron-quercetin complex (IronQ) possesses extraordinary dual capabilities with a stimulating agent for cell growth and an imaging probe by magnetic resonance imaging (MRI). Therefore, we hypothesized that IronQ could improve the survival and viability of MSCs, displaying the anti-inflammation function in the treatment of ICH while also labeling MSCs for their tracking by MRI. This study aimed to explore the effects of MSCs with IronQ in regulating inflammation and further clarify their potential mechanisms.

METHODS

C57BL/6 male mice were utilized in this research. A collagenase I-induced ICH mice model was established and randomly separated into the model group (Model), quercetin gavage group (Quercetin), MSCs transplantation group (MSCs), and MSCs transplantation combined with IronQ group (MSCs + IronQ) after 24 h. Then, the neurological deficits score, brain water content (BWC), and protein expression, such as TNF-α, IL-6, NeuN, MBP, as well as GFAP, were investigated. We further measured the protein expression of Mincle and its downstream targets. Furthermore, the lipopolysaccharide (LPS)-induced BV2 cells were utilized to investigate the neuroprotection of conditioned medium of MSCs co-cultured with IronQ in vitro.

RESULTS

We found that the combined treatment of MSCs with IronQ improved the inflammation-induced neurological deficits and BWC in vivo by inhibiting the Mincle/syk signaling pathway. Conditioned medium derived from MSCs co-cultured with IronQ decreased inflammation, Mincle, and its downstream targets in the LPS-induced BV2 cell line.

CONCLUSIONS

These data suggested that the combined treatment exerts a collaborative effect in alleviating ICH-induced inflammatory response through the downregulation of the Mincle/syk signaling pathway following ICH, further improving the neurologic deficits and brain edema.

Iron(III)-Quercetin Complexes' Safety for MRI Cell Tracking in Cell Therapy Applications: Cytotoxic and Genotoxic Assessment

The theranostic agent iron-quercetin complex (IronQ) provides a T1-positive magnetic resonance imaging (MRI) contrast agent. The magnetically IronQ-labeled cells can be used for cell tracking and have active biological applications in promoting cell and tissue regeneration. However, a detailed investigation of IronQ's cytotoxicity and genotoxicity is necessary. Thus, this study aimed to evaluate the possibility of IronQ inducing cytotoxicity and genotoxicity in peripheral blood mononuclear cells (PBMCs). We evaluated the vitality of cells, the production of reactive oxygen species (ROS), the level of antioxidant enzymes, and the stability of the genetic material in PBMCs treated with IronQ. The results show that IronQ had a negligible impact on toxicological parameters such as ROS production and lipid peroxidation, indicating that it is not harmful. IronQ-labeled PMBCs experienced an insignificant depletion of antioxidant enzyme levels at the highest concentration of IronQ. There is no evident genotoxicity in the magnetically IronQ-labeled PBMCs. The results show that IronQ does not potentiate the cytotoxicity and genotoxicity effects of the labeled PMBCs and might be safe for therapeutic and cell tracking purposes. These results could provide a reference guideline for the toxicological analysis of IronQ in in vivo studies.