Mesoporous zinc-polyphenol nanozyme for attenuating renal ischemia-reperfusion injury.

Aim: To target the reactive oxygen species (ROS) accumulation and renal tubular epithelial cell (rTEC) death in renal ischemia-reperfusion injury (IRI), we constructed a nanoparticle that offers ROS scavenging and rTEC-death inhibition: mesoporous zinc-tannic acid nanozyme (ZnTA). Materials & methods: After successfully constructing ZnTA, we proceeded to examine its effect on ROS accumulation, cellular ferroptosis and apoptosis, as well as injury severity. Results: Malondialdehyde, Fe2+ amounts and 4-HNE staining demonstrated that ZnTA effectively attenuated rTEC ferroptosis. TUNEL staining confirmed that Zn2+ carried by ZnTA could effectively inhibit caspase 3 and caspase 9, mitigating apoptosis. Finally, it reduced renal IRI through the synergistic effect of ROS scavenging and cell-death inhibition. Conclusion: This study is expected to provide a paradigm for a combined therapeutic strategy for renal IRI.

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Reactive Oxygen Species-Scavenging Mesoporous Poly(tannic acid) Nanospheres Alleviate Acute Kidney Injury by Inhibiting Ferroptosis.

Acute kidney injury (AKI), predominantly associated with the excess production of endogenous ROS, is a serious renal dysfunction syndrome. Ferroptosis characterized by iron-dependent regulated cell death has significant involvement in AKI pathogenesis. As symptomatic treatment of AKI remains clinically limited, a new class of effective therapies has emerged, which is referred to as nanozyme. In our research, a natural mesoporous poly(tannic acid) nanosphere (referred to as PTA) was developed that can successfully mimic the activity of superoxide dismutase (SOD) by Mussel-inspired interface deposition strategy, for effective ROS scavenging and thus inhibition of ferroptosis to attenuate AKI. As anticipated, PTA mitigated oxidative stress and inhibited ferroptosis, as opposed to other modes of cell death such as pyroptosis or necrosis. Furthermore, PTA exhibited favorable biocompatibility and safeguarded the kidney against ferroptosis by enhancing the expression of SLC7a11/glutathione peroxidase 4(GPX4) and Nrf2/HO-1, while reducing the levels of ACSL4 protein in the ischemia and reperfusion injury (IRI)-induced AKI model. Moreover, PTA effectively suppressed aberrant expression of inflammatory factors. Overall, this study introduced antioxidative nanozymes in the form of mesoporous polyphenol nanospheres, showcasing exceptional therapeutic efficacy in addressing ROS-related diseases. This novel approach holds promise for clinical AKI treatment and broadens the scope of biomedical applications for nanozymes.

Cellular delivery of relaxin-2 mRNA as a potential treatment for kidney fibrosis.

Renal fibrosis is a pathological feature of chronic kidney disease and its progression correlates with kidney function impairment. Since there are currently no specific therapies for renal fibrosis, we explored whether inducing local production of the anti-fibrotic molecule relaxin-2 in kidney cells has potential as a strategy for suppressing the development of renal fibrosis. Our study examined whether delivery of relaxin-2 mRNA to kidney cells in vitro and in vivo could inhibit mechanisms leading to renal fibrosis. Transfecting relaxin-2 mRNA into cultured kidney cells inhibited fibrotic responses to TGF-ß1 in an autocrine or paracrine manner by reducing fibrotic gene expression in kidney tubules, and reducing proliferation in kidney fibroblasts and mesangial cells. Similarly, cubosomes assisted delivery of relaxin-2 mRNA to mouse kidneys alleviated the fibrosis and inflammation associated with renal injury following unilateral ureter obstruction (UUO). Therefore, relaxin-2 mRNA exhibits potential as a novel therapy for inhibiting fibrosis and inflammation in chronic kidney disease.

Neutrophil Membrane-Inspired Nanorobots Act as Antioxidants Ameliorate Ischemia Reperfusion-Induced Acute Kidney Injury.

Ischemia/reperfusion (I/R) injury causes excessive oxidative events and initiates destructive inflammatory responses, and it is an important promoter to the pathology of various pathema states. Ferroptosis is an iron-dependent type of nonapoptotic cell death accompanied by the accumulation of membrane lipid peroxide and consumption of polyunsaturated fatty acid, and it plays a key role in I/R injury diseases. Moreover, the excessive production of inflammatory cytokines contributes to the development of acute kidney injury. Here, we reported neutrophil membrane-coated copper-based nanoparticles (N-Cu5.4O@DFO NPs) for I/R kidney injury treatment. The highly biocompatible and stable N-Cu5.4O@DFO NPs showed excellent antioxidant and iron ion scavenging abilities in vitro. Our finding showed that the N-Cu5.4O@DFO NPs strategy could significantly accumulate in the inflammatory kidney, reduce oxidative damage events and inflammatory response, and finally achieve synergistic therapy against renal I/R injury. This work promotes the development of nanoantioxidant agents with multiple antioxidant properties for the therapy of other I/R injury diseases.

HLA class II antibody activation of endothelial cells induces M2 macrophage differentiation in peripheral blood.

BACKGROUND: Donor-specific human leukocyte antigen (HLA) class II antibodies (HLA-II Abs) combined with allogeneic endothelial cells (ECs) mediate high-risk rejection in kidney transplant patients. Macrophage accumulation is a significant histological feature of antibody-mediated rejection (AMR) in kidney transplant patients. Here, we further investigated the effect of HLA-II Abs on macrophage phenotypes to provide theoretical basis for clinical treatment of AMR. METHODS: We prepared an experimental model containing HLA-II Ab-stimulated microvascular ECs and peripheral blood mononuclear cells (PBMCs) co-culture and explored the potential relationship of HLA-II Ab, ECs activation, and macrophage differentiation. Immune phenotype of macrophage subsets was analyzed and quantified by flow cytometry. HLA-II Ab activation of ECs induces M2 macrophage differentiation signal pathways which were investigated by qPCR and western blotting. RESULTS: The stimulation of ECs by F(ab')2 fragment of HLA-II Abs led to phosphorylation of PI3K, Akt, and mTOR, which mediated IL-10, ICAM-1, VCAM-1 secretion. The enhanced ICAM-1 and IL-10 promoted the migration of PBMCs and their differentiation into CD68+ and CD163+ (M2-type) macrophages, respectively, but not CD86+ macrophages. CONCLUSION: These findings revealed the PI3K/Akt/mTOR signal pathways activated by HLA-II Abs in ECs and the immune regulation ability of HLA-II Abs to induce PBMC differentiation.