MicroRNA-103a-3p enhances sepsis-induced acute kidney injury via targeting CXCL12

miR-16-5p aggravates sepsis-associated acute kidney injury by inducing apoptosis

Sepsis-associated acute kidney injury (S-AKI) is a common disease in pediatric intensive care units (ICU) with high morbidity and mortality. The newly discovered results indicate that microRNAs (miRNAs) play an important role in the diagnosis and treatment of S-AKI and can be used as markers for early diagnosis. In this study, the expression level of miR-16-5p was found to be significantly upregulated about 20-fold in S-AKI patients, and it also increased by 1.9 times in the renal tissue of S-AKI mice. Receiver operating characteristic (ROC) curve analysis showed that miR-16-5p had the highest predictive accuracy in the diagnosis of S-AKI (AUC = 0.9188). In vitro, the expression level of miR-16-5p in HK-2 cells treated with 10 μg/mL lipopolysaccharide (LPS) increased by more than 2 times. In addition, LPS-exposed renal tissue and HK-2 cells lead to upregulation of inflammatory cytokines IL-6, IL-1β, TNF-a, and kidney damage molecules kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL). However, inhibition of miR-16-5p significantly mitigated LPS expose-mediated kidney injury and inflammation. Furthermore, LPS-exposed HK-2 cells increased more than 1.7-fold the expression levels of Bax and caspase-3, decreased 3.2-fold the expression level of B-cell lymphoma-2 (Bcl-2), and significantly promoted the occurrence of apoptosis. MiR-16-5p mimic further increased LPS-induced apoptosis in HK-2 cells. Nevertheless, inhibition of miR-16-5p significantly attenuated this effect. In summary, up-regulation of miR-16-5p expression can significantly aggravate renal injury and apoptosis in S-AKI, which also proves that miR-16-5p can be used as a potential biomarker to promote early identification of S-AKI.

Inhibition of sepsis-induced acute kidney injury via the circITCH-miR-579-3p-ZEB2 axis

Circular RNAs (circRNAs) are linked to the regulation of sepsis-induced acute kidney injury (AKI). However, the function of circITCH in the development of sepsis-induced AKI is still unclear. The levels of circITCH, miR-579-3p and ZEB2 were examined by real-time PCR and immunoblotting. Then, the roles of circITCH in cell viability, apoptosis, and inflammation in lipopolysaccharide (LPS)-treated HK-2 cells were evaluated. The further mechanism was investigated using rescue assays. CircITCH was downregulated in septic AKI patients and LPS-triggered HK-2 cells. CircITCH overexpression restored cell viability in LPS-treated HK-2 cells and restrained apoptosis and inflammatory cytokine production. CircITCH negatively regulated miR-579-3p, thereby upregulating ZEB2 expression. Taken together, circITCH alleviates LPS-induced HK-2 cell injury by regulating miR-579-3p/ZEB2 signal axis, which provides a theoretical basis for AKI therapy.

Vancomycin Induced Ferroptosis in Renal Injury Through the Inactivation of Recombinant Glutathione Peroxidase 4 and the Accumulation of Peroxides

Background

Vancomycin (VCM) has long been used clinically to fight against Gram-positive bacterial infections. In recent decades, an increased number of kidney injury cases caused by VCM overdose have been reported. In this study, we further investigated the mechanism of VCM-overdose-induced kidney injury.

Methods

Immunohistochemistry (IHC) staining, RT-qPCR and Western blot assays were used to determine ki67, DDX5, PTGS2, GPX4 and SLC7A11 expressions in the kidney tissues of mice. CCK-8 and flow cytometry assays were used to determine HK2 cell viability and apoptosis. In addition, RT-qPCR and Western blot assays was applied to evaluate the expressions of ACSL4, PTGS2, GPX4, SLC7A11, DDX5 and Ki67 in HK2 cells.

Results

We found that VCM induced ferroptosis in vitro and in vivo. Ferrostatin-1 (Fer-1) is a potent inhibitor of ferroptosis, Fer-1 rescued cell viability and renal function renal morphology in VCM-treated cells and mice, respectively. Further, GPX4, which plays an essential role in reducing lipid hydroperoxides and preventing ferroptosis, was observed to be downregulated by VCM treatment. Interestingly, we found that GPX4-knockdown HK-2 cells exhibited a similar phenotype and gene expression level of ACSL4, PTGS2, DDX5 and Ki67 compared with VCM-treated cells, which suggested that VCM could induce ferroptosis in HK2 cells by down-regulating GPX4.

Conclusion

In conclusion, VCM induced renal injury in the kidney tissues of mice. In addition, VCM induced ferroptosis cell death in HK-2 cells and in the kidney tissues of mice by down-regulating GPX4 and causing the accumulation of peroxides. These data suggested that VCM could induce renal injury in vitro and in vivo via triggering ferroptosis. This study further elucidates the mechanism of VCM-induced renal injury and provides additional references for clinical use of VCM.

Expression of MicroRNAs in Sepsis-Related Organ Dysfunction: A Systematic Review

Sepsis is a critical condition characterized by increased levels of pro-inflammatory cytokines and proliferating cells such as neutrophils and macrophages in response to microbial pathogens. Such processes lead to an abnormal inflammatory response and multi-organ failure. MicroRNAs (miRNA) are single-stranded non-coding RNAs with the function of gene regulation. This means that miRNAs are involved in multiple intracellular pathways and thus contribute to or inhibit inflammation. As a result, their variable expression in different tissues and organs may play a key role in regulating the pathophysiological events of sepsis. Thanks to this property, miRNAs may serve as potential diagnostic and prognostic biomarkers in such life-threatening events. In this narrative review, we collect the results of recent studies on the expression of miRNAs in heart, blood, lung, liver, brain, and kidney during sepsis and the molecular processes in which they are involved. In reviewing the literature, we find at least 122 miRNAs and signaling pathways involved in sepsis-related organ dysfunction. This may help clinicians to detect, prevent, and treat sepsis-related organ failures early, although further studies are needed to deepen the knowledge of their potential contribution.