p53 activates miR-192-5p to mediate vancomycin induced AKI

Exploring shared pathogenesis of multiple myeloma and osteoporosis via bioinformatic analysis

BACKGROUND

The purpose of this study is to explore the common differentially expressed genes (DEGs) between multiple myeloma (MM) and osteoporosis and the associated molecular mechanisms.

RESEARCH DESIGN AND METHODS

We obtained the overlapping DEGs between MM and osteoporosis with the GEO2R online tool. Then, the DEGs were clustered on the MetaCore website to identify the biological process and pathway. In addition, the STRING database and Cytoscape were used to construct the protein-protein interaction (PPI) network and identify hub genes. Finally, miRNA-gene and transcriptional factor (TF)-gene interaction networks were constructed.

RESULTS

A total of 252 genes were identified as DEGs in the overlapping two datasets. Functional analysis emphasizes the crucial role of the cell cycle in these two diseases. 10 hub genes were identified using cytoHubba, including CCNA2, ASPM, MKI67, FN1, FEN1, STAT1, DEPDC1, ITGB8, DYNC2LI1, HBEGF. In addition, according to the miRNA-gene and TF-gene interaction networks, part of TFs (RELA, TP53), and miRNAs (miR-26b-5p, miR-192-5p) may be identified as key regulators in MM and osteoporosis at the same time.

CONCLUSIONS

The present study reveals the common pathogenesis of MM and osteoporosis. These shared pathways may provide new targets for further mechanistic studies of the pathogenesis and treatment of MM and osteoporosis.

MicroRNA dysregulation in myelodysplastic syndromes: implications for diagnosis, prognosis, and therapeutic response

Myelodysplastic syndromes (MDS) are a group of malignant clonal hematological disorders with heterogeneous clinical course and risk of transformation to acute myeloid leukemia. Genetic and epigenetic dysregulation, including alterations in microRNA (miRNA) expression, plays a pivotal role in MDS pathogenesis influencing disease development and progression. MiRNAs, known for their regulatory roles in gene expression, have emerged as promising biomarkers in various malignant diseases. This review aims to explore the diagnostic and prognostic roles of miRNAs in MDS. We discuss research efforts aimed at understanding the clinical utility of miRNAs in MDS management. MiRNA dysregulation is linked to specific chromosomal abnormalities in MDS, providing insights into the molecular landscape of the disease. Circulating miRNAs in plasma offer a less invasive avenue for diagnostic and prognostic assessment, with distinct miRNA profiles identified in MDS patients. Additionally, we discuss investigations concerning the role of miRNAs as markers for treatment response to hypomethylating and immunomodulating agents, which could lead to improved treatment decision-making and monitoring. Despite significant progress, further research in larger patient cohorts is needed to fully elucidate the role of miRNAs in MDS pathogenesis and refine personalized approaches to patient care.

Cell death induced by acute renal injury: a perspective on the contributions of accidental and programmed cell death

The involvement of cell death in acute kidney injury (AKI) is linked to multiple factors including energy depletion, electrolyte imbalance, reactive oxygen species, inflammation, mitochondrial dysfunction, and activation of several cell death pathway components. Since our review in 2003, discussing the relative contributions of apoptosis and necrosis, several other forms of cell death have been identified and are shown to contribute to AKI. Currently, these various forms of cell death can be fundamentally divided into accidental cell death and regulated or programmed cell death based on functional aspects. Several death initiator and effector molecules switch molecules that may act as signaling components triggering either death or protective mechanisms or alternate cell death pathways have been identified as part of the machinery. Intriguingly, several of these cell death pathways share components and signaling pathways suggesting complementary or compensatory functions. Thus, defining the cross talk between distinct cell death pathways and identifying the unique molecular effectors for each type of cell death may be required to develop novel strategies to prevent cell death. Furthermore, depending on the multiple forms of cell death simultaneously induced in different AKI settings, strategies for combination therapies that block multiple cell death pathways need to be developed to completely prevent injury, cell death, and renal function. This review highlights the various cell death pathways, cross talk, and interactions between different cell death modalities in AKI.

Proximal tubular MBD2 promotes autophagy to drive the progression of AKI caused by vancomycin via regulation of miR-597-5p/S1PR1 axis

Our recent investigation has indicated that the global deletion of MBD2 can mitigate the progression of AKI induced by VAN. Nevertheless, the role and regulatory mechanisms of proximal tubular MBD2 in this pathophysiological process have yet to be elucidated. Our preceding investigation revealed that autophagy played a crucial role in advancing AKI induced by VAN. Consequently, we postulated that MBD2 present in the proximal tubule could upregulate the autophagic process to expedite the onset of AKI. In the present study, we found for the first time that MBD2 mediated the autophagy production induced by VAN. Through the utilization of miRNA chip analysis, we have mechanistically demonstrated that MBD2 initiates the activation of miR-597-5p through promoter demethylation. This process leads to the suppression of S1PR1, which results in the induction of autophagy and apoptosis in renal tubular cells. Besides, PT-MBD2-KO reduced autophagy to attenuate VAN-induced AKI via regulation of the miR-597-5p/S1PR1 axis, which was reversed by rapamycin. Finally, the overexpression of MBD2 aggravated the diminished VAN-induced AKI in autophagy-deficient mice (PT-Atg7-KO). These data demonstrate that proximal tubular MBD2 facilitated the process of autophagy via the miR-597-5p/S1PR1 axis and subsequently instigated VAN-induced AKI through the induction of apoptosis. The potentiality of MBD2 being a target for AKI was established.

MicroRNA-192-5p downregulates Fat Mass and Obesity-associated Protein to aggravate renal ischemia/reperfusion injury

Acute kidney injury (AKI) is a common disorder without effective therapy yet. Renal ischemia/reperfusion (I/R) injury is a common cause of AKI. MicroRNA miR-192-5p has been previously reported to be upregulated in AKI models. However, its functional role in renal I/R injury is not fully understood. This study aimed to investigate the effects and the underlying mechanism of miR-192-5p in renal I/R progression. Hypoxia/reoxygenation (H/R)-induced cell injury model in HK-2 cells and I/R-induced renal injury model in mice were established in this study. Cell counting kit-8 assay was performed to determine cell viability. Quantitative real-time PCR and western blot analysis were performed to detect gene expressions. Hematoxylin-eosin and periodic acid-Schiff staining were performed to observe the histopathological changes. Enzyme-linked immunosorbent assay was performed to detect the kidney markers' expression. In vivo and in vitro results showed that miR-192-5p was up-regulated in the I/R-induced mice model and H/R-induced cell model, and miR-192-5p overexpression exacerbated I/R-induced renal damage. Then, the downstream target of miR-192-5p was analyzed by combining the differentially expressed mRNAs and the predicted genes and confirmed using a dual-luciferase reporter assay. It was found that miR-192-5p was found to regulate fat mass and obesity-associated (FTO) protein expression by directly targeting the 3' untranslated region of FTO mRNA. Moreover, in vivo and in vitro studies unveiled that FTO overexpression alleviated renal I/R injury and promoted HK-2 cell viability via stimulating autophagy flux. In conclusion, miR-192-5p aggravated I/R-induced renal injury by blocking autophagy flux via down-regulating FTO.

Emodin prevents renal ischemia-reperfusion injury via suppression of p53-mediated cell apoptosis based on network pharmacology

Background

Previous evidence indicated that emodin has significant advantages for preventing acute kidney injury (AKI). However, the mechanisms responsible for these effects of emodin have yet to be elucidated.

Methods

We first used network pharmacology and molecular docking to identify the core targets of emodin for AKI and performed a range of experiments to validate this result. Pretreatment with emodin for 7 days, the rats were treated with bilateral renal artery clipping for 45 min to identify the prevention effect. Hypoxia/reoxygenation (H/R), and vancomycin - induced renal tubular epithelial cells (HK-2 cells) were treated with emodin to explore the related molecular mechanism.

Results

Network pharmacology and molecular docking showed that anti-apoptosis might be the core mechanism responsible for the action of emodin on AKI; this anti-apoptotic effect appears to because by regulation p53-related signaling pathway. Our data showed that pretreatment with emodin significantly improved renal function and renal tubular injury in renal I/R model rats (P < 0.05. The prevention effect of emodin was proved to be related to anti - apoptosis of HK-2 cells, possibly by downregulating the levels of p53, cleaved-caspase-3, pro-caspase-9, and upregulated the levels of Bcl-2. The efficacy and mechanism of emodin on anti - apoptosis was also confirmed in vancomycin - induced HK-2 cells. Meanwhile, the data also showed that emodin promoted angiogenesis in I/R damaged kidneys and H/R-induced HK-2 cells, which was associated with decreasing HIF-1α levels and increasing VEGF levels.

Conclusions

Our findings indicated that the preventive effect of emodin on AKI is probably attributable to anti-apoptosis response and promoting angiogenesis effect.

Knockdown of deleterious miRNA in progenitor cell-derived small extracellular vesicles enhances tissue repair in myocardial infarction

Small extracellular vesicles (sEVs) play a critical role in cardiac cell therapy by delivering molecular cargo and mediating cellular signaling. Among sEV cargo molecule types, microRNA (miRNA) is particularly potent and highly heterogeneous. However, not all miRNAs in sEV are beneficial. Two previous studies using computational modeling identified miR-192-5p and miR-432-5p as potentially deleterious in cardiac function and repair. Here, we show that knocking down miR-192-5p and miR-432-5p in cardiac c-kit+ cell (CPC)-derived sEVs enhances the therapeutic capabilities of sEVs in vitro and in a rat in vivo model of cardiac ischemia reperfusion. miR-192-5p- and miR-432-5p-depleted CPC-sEVs enhance cardiac function by reducing fibrosis and necrotic inflammatory responses. miR-192-5p-depleted CPC-sEVs also enhance mesenchymal stromal cell-like cell mobilization. Knocking down deleterious miRNAs from sEV could be a promising therapeutic strategy for treatment of chronic myocardial infarction.

A miRNA screening identifies miR-192-5p as associated with response to azacitidine and lenalidomide therapy in myelodysplastic syndromes

BACKGROUND

miRNAs are small non-coding RNAs that regulate gene expression and are linked to cancer development and progression. miRNA profiles are currently studied as new prognostic factors or therapeutic perspectives. Among hematological cancers, myelodysplastic syndromes at higher risk of evolution into acute myeloid leukemia are treated with hypomethylating agents, like azacitidine, alone or in combination with other drugs, such as lenalidomide. Recent data showed that, during azacitidine and lenalidomide therapy, the concurrent acquisition of specific point mutations affecting inositide signalling pathways is associated with lack or loss of response to therapy. As these molecules are implicated in epigenetic processes, possibly involving miRNA regulation, and in leukemic progression, through the regulation of proliferation, differentiation and apoptosis, here we performed a new miRNA expression analysis of 26 high-risk patients with myelodysplastic syndromes treated with azacitidine and lenalidomide at baseline and during therapy. miRNA array data were processed, and bioinformatic results were correlated with clinical outcome to investigate the translational relevance of selected miRNAs, while the relationship between selected miRNAs and specific molecules was experimentally tested and proven.

RESULTS

Patients' overall response rate was 76.9% (20/26 cases): complete remission (5/26, 19.2%), partial remission (1/26, 3.8%), marrow complete remission (2/26, 7.7%), hematologic improvement (6/26, 23.1%), hematologic improvement with marrow complete remission (6/26, 23.1%), whereas 6/26 patients (23.1%) had a stable disease. miRNA paired analysis showed a statistically significant up-regulation of miR-192-5p after 4 cycles of therapy (vs baseline), that was confirmed by real-time PCR analyses, along with an involvement of BCL2, that was proven to be a miR-192-5p target in hematopoietic cells by luciferase assays. Furthermore, Kaplan-Meier analyses showed a significant correlation between high levels of miR-192-5p after 4 cycles of therapy and overall survival or leukemia-free survival, that was stronger in responders, as compared with patients early losing response and non-responders.

CONCLUSIONS

This study shows that high levels of miR-192-5p are associated with higher overall survival and leukemia-free survival in myelodysplastic syndromes responding to azacitidine and lenalidomide. Moreover, miR-192-5p specifically targets and inhibits BCL2, possibly regulating proliferation and apoptosis and leading to the identification of new therapeutic targets.

HIPK2 as a Novel Regulator of Fibrosis

Fibrosis is an unmet medical problem due to a lack of evident biomarkers to help develop efficient targeted therapies. Fibrosis can affect almost every organ and eventually induce organ failure. Homeodomain-interacting protein kinase 2 (HIPK2) is a protein kinase that controls several molecular pathways involved in cell death and development and it has been extensively studied, mainly in the cancer biology field. Recently, a role for HIPK2 has been highlighted in tissue fibrosis. Thus, HIPK2 regulates several pro-fibrotic pathways such as Wnt/β-catenin, TGF-β and Notch involved in renal, pulmonary, liver and cardiac fibrosis. These findings suggest a wider role for HIPK2 in tissue physiopathology and highlight HIPK2 as a promising target for therapeutic purposes in fibrosis. Here, we will summarize the recent studies showing the involvement of HIPK2 as a novel regulator of fibrosis.

The Characterization and Differential Analysis of m6A Methylation in Hycole Rabbit Muscle and Adipose Tissue and Prediction of Regulatory Mechanism about Intramuscular Fat

N6-methyladenosine (m⁶A) widely participates in various life processes of animals, including disease, memory, growth and development, etc. However, there is no report on m⁶A regulating intramuscular fat deposition in rabbits. In this study, m⁶A modification of Hycole rabbit muscle and adipose tissues were detected by MeRIP-Seq. In this case, 3 methylases and 12 genes modified by m⁶A were found to be significantly different between muscle and adipose tissues. At the same time, we found 3 methylases can regulate the expression of 12 genes in different ways and the function of 12 genes is related to fat deposition base on existing studies. 12 genes were modified by m⁶A methylase in rabbit muscle and adipose tissues. These results suggest that 3 methylases may regulate the expression of 12 genes through different pathways. In addition, the analysis of results showed that 6 of the 12 genes regulated eight signaling pathways, which regulated intramuscular fat deposition. RT-qPCR was used to validate the sequencing results and found the expression results of RT-qPCR and sequencing results are consistent. In summary, METTL4, ZC3H13 and IGF2BP2 regulated intramuscular fat by m⁶A modified gene/signaling pathways. Our work provided a new molecular basis and a new way to produce rabbit meat with good taste.

LncRNA ENSMUST_147219 mediates the progression of ischemic acute kidney injury by targeting the miR-221-5p/IRF6 axis

Although previous studies have revealed that long noncoding RNAs (lncRNAs) regulate the progression of ischemic acute kidney injury (AKI), the exact role and mechanism of lncRNA ENSMUST_147219 in ischemic AKI are not clear. In the present study, lncRNA ENSMUST_147219 was induced by ischemic injury in vitro and in vivo. Functionally, lncRNA ENSMUST_147219 mediated apoptosis in mouse proximal tubule‐derived cell line (BUMPT). Mechanistically, lncRNA ENSMUST_147219 sponged the microRNA (miR)-221-5p to upregulate the expression of interferon regulatory factor 6 (IRF6) to drive apoptosis. Finally, knockdown of lncRNA ENSMUST_147219 markedly attenuated the ischemic AKI by targeting the miR-221-5p/IRF6 axis. Collectively, our data demonstrated that lncRNA ENSMUST_147219 promoted the development of ischemic AKI by regulating the miR-221-5p/IRF6 pathway, which could be considered a new therapeutic target for ischemic AKI.

Expression and 7-day time course of circulating microRNAs in septic patients treated with nephrotoxic antibiotic agents

Background

Through regulation of signaling pathways, microRNAs (miRNAs) can be involved in sepsis and associated organ dysfunction. The aims of this study were to track the 7-day time course of blood miRNAs in patients with sepsis treated with vancomycin, gentamicin, or a non-nephrotoxic antibiotic and miRNA associations with neutrophil gelatinase-associated lipokalin (NGAL), creatinine, procalcitonin, interleukin-6, and acute kidney injury (AKI) stage.

Methods

Of 46 adult patients, 7 were on vancomycin, 20 on gentamicin, and 19 on another antibiotic. Blood samples were collected on days 1, 4, and 7 of treatment, and miRNAs were identified using quantitative reverse transcription PCR.

Results

The results showed no relationship between miRNA levels and biochemical variables on day 1. By day 7 of gentamicin treatment miR-15a-5p provided good discrimination between AKI and non-AKI (area under curve, 0.828). In patients taking vancomycin, miR-155-5p and miR-192-5p positively correlated with creatinine and NGAL values, and miR-192-5p and miR-423-5p positively correlated with procalcitonin and interleukin-6 in patients treated with a non-nephrotoxic antibiotic. In patients together we found positive correlation between miR-155-5p and miR-423-5p and all biochemical markers.

Conclusion

The results suggest that these four miRNAs may serve as diagnostic or therapeutic tool in sepsis, renal injury and nephrotoxic treatment.

Trial registration

ClinicalTrials.gov, ID: NCT04991376. Registered on 27 July 2021.

Pifithrin-α ameliorates glycerol induced rhabdomyolysis and acute kidney injury by reducing p53 activation

Objectives

Rhabdomyolysis is a series of symptoms caused by the dissolution of striped muscle, and acute kidney injury (AKI) is a potential complication of severe rhabdomyolysis. The underlying causes of AKI are remarkably complex and diverse. Here, we aim to investigate whether pifithrin-α protected against rhabdomyolysis-induced AKI and to determine the involved mechanisms.

Methods

Intramuscular injection in the right thigh caudal muscle of C57BL/6J mice with 7.5 ml/kg saline (Group A) or of the same volume 50% glycerol was used to induce rhabdomyolysis and subsequent AKI (Group B). Pifithrin-α was injected intraperitoneally 4 h before (Group C) or 4 h after (Group D) the glycerol injection. Serum creatine kinase, blood urea nitrogen, and creatinine were determined, and the renal cortex was histologically analyzed. Renal expression levels of interested mRNAs and proteins were determined and compared, too.

Results

Intramuscular injection of glycerol induced rhabdomyolysis and subsequent AKI in mice (Groups B–D). Renal function reduction and histologic injury of renal tubular epithelial cells were associated with increased p53 activation, oxidative stress, and inflammation. Notably, compared with pifithrin-α rescue therapy (Group D), pretreatment of pifithrin-α (Group C) protected the mice from severe injury more effectively.

Conclusions

Our present study suggests that p53 may be a therapeutic target of AKI caused by glycerol, and the inhibition of p53 can block glycerol-mediated AKI by using pharmacological agents instead of genetic inhibitory approaches, which further supports that p53 played a pivotal role in renal tubular injury when challenged with glycerol.

DsbA-L interacts with VDAC1 in mitochondrion-mediated tubular cell apoptosis and contributes to the progression of acute kidney disease

BACKGROUND

we demonstrated that disulfide-bond A oxidoreductase-like protein (DsbA-L) was involved in the progression of renal fibrosis. However, the precise function of DsbA-L in acute kidney injury (AKI), and the mechanisms involved, have yet to be elucidated.

METHODS

We illustrate the DsbA-L interacted with VDAC1 by co-IP (co-immunoprecipitation) in vitro and vivo, and found the interaction parts of them by mutation experiment. The above findings were verified by co-localization of them. In addition, we constructed the two model of PT-DsbA-L and VDAC1 KO mice to verify the function of DsbA-L and VDAC1 in models of VAN, CLP and I/R-induced AKI.

FINDINGS

The PT-DsbA-L-KO mice showed amelioration of I/R, VAN-, and CLP-induced AKI progression via the downregulation of VDAC1. Finally, we confirmed these changes in signal molecules by examining in HK-2 cells and kidney biopsies taken from patients with ischemic or acute interstitial nephritis (AIN)-induced AKI. Mechanistically, DsbA-L interacted with amino acids 9-13 and 22-27 of VDAC1 in the mitochondria of BUMPT cells to induce renal cell apoptosis and mitochondrial injury.

INTERPRETATION

This work suggested that DsbA-L, located in the proximal tubular cells, drives the progression of AKI, by directly upregulating the levels of VDAC1.Running Title: The role of DsbA-L in AKI FUNDING: National Natural Science Foundation of China, a grant from Key Project of Hunan provincial science and technology innovation, Department of Science and Technology of Hunan Province project of International Cooperation and Exchanges, Changsha Science and Technology Bureau project, Natural Science Foundation of Hunan Province, Fundamental Research Funds for the Central Universities of Central South University, Hunan Provincial Innovation Foundation For Postgraduate China Hunan Provincial Science and Technology Department.

Preferential siRNA delivery to injured kidneys for combination treatment of acute kidney injury

Acute kidney injury (AKI) is characterized by a sudden loss of renal function and is associated with high morbidity and mortality. Tumor suppressor p53 and chemokine receptor CXCR4 were both implicated in the AKI pathology. Here, we report on the development and evaluation of polymeric CXCR4 antagonist (PCX) siRNA carrier for selective delivery to injured kidneys in AKI. Our results show that PCX/siRNA nanoparticles (polyplexes) provide protection against cisplatin injury to tubule cells in vitro when both CXCR4 and p53 are inhibited. The polyplexes selectively accumulate and are retained in the injured kidneys in cisplatin and bilateral ischemia reperfusion injury models of AKI. Treating AKI with the combined CXCR4 inhibition and p53 gene silencing with the PCX/sip53 polyplexes improves kidney function and decreases renal damage. Overall, our results suggest that the PCX/sip53 polyplexes have a significant potential to enhance renal accumulation in AKI and deliver therapeutic siRNA.

Anti-oxidant, anti-apoptotic, and mitochondrial regulatory effects of selenium nanoparticles against vancomycin induced nephrotoxicity in experimental rats

AIM

Nephrotoxicity is the major limiting factor for the clinical use of vancomycin (VCM) for treatment against multi-resistant Gram-positive bacteria. The present research aimed to investigate the ability of selenium nanoparticles (SeNPs) to protect against VCM-induced nephrotoxicity in rats.

MAIN METHODS

Experimental rats were divided into five groups; the first was the normal control, the second was treated with VCM (200 mg/kg twice/day, i.p.) for 7 days. The third, fourth, and fifth groups were treated orally with SeNPs (0.5, 1, and 2 mg/kg/day); respectively. SeNPs were administered for 12 days before VCM, 1 week simultaneously with VCM, and for another 1 week after its administration.

KEY FINDINGS

Levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), and kidney injury molecule-1 (KIM-1) were significantly increased in kidney tissue after VCM administration. Expression of adenosine 5'-monophosphate-activated protein kinase (AMPK), Bcl-2 associated X protein (Bax), caspase 3 and caspase 9 in kidney tissue was significantly increased, while the antioxidant enzymes, mitochondrial complexes, the ATP levels and B-cell lymphoma protein 2 (Bcl-2) were decreased in kidney in the VCM-treated rats compared to the normal control group. Treatment with SeNPs significantly decreased levels of MDA, iNOS, NO, TNF-α, and KIM-1 in the kidney tissue. Administration of SeNPs also downregulated the expression of the proapoptotic agents and enhanced the activities of the antioxidant enzymes and the mitochondrial enzyme complexes in the kidney.

SIGNIFICANCE

SeNPs alleviated VCM-induced nephrotoxicity through their anti-oxidant, anti-inflammatory, anti-apoptotic and mitochondrial protective effects.

Metabolic and Lipidomic Assessment of Kidney Cells Exposed to Nephrotoxic Vancomycin Dosages

Vancomycin is a glycopeptide antibiotic used against multi-drug resistant gram-positive bacteria such as Staphylococcus aureus (MRSA). Although invaluable against resistant bacteria, vancomycin harbors adverse drug reactions including cytopenia, ototoxicity, as well as nephrotoxicity. Since nephrotoxicity is a rarely occurring side effect, its mechanism is incompletely understood. Only recently, the actual clinically relevant concentration the in kidneys of patients receiving vancomycin was investigated and were found to exceed plasma concentrations by far. We applied these clinically relevant vancomycin concentrations to murine and canine renal epithelial cell lines and assessed metabolic and lipidomic alterations by untargeted and targeted gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry analyses. Despite marked differences in the lipidome, both cell lines increased anabolic glucose reactions, resulting in higher sorbitol and lactate levels. To the best of our knowledge, this is the first endometabolic profiling of kidney cells exposed to clinically relevant vancomycin concentrations. The presented study will provide a valuable dataset to nephrotoxicity researchers and might add to unveiling the nephrotoxic mechanism of vancomycin.

Circulating Extracellular Vesicles Carry Immune Regulatory miRNAs and Regulate Vaccine Efficacy and Local Inflammatory Response After Vaccination

Vaccination is the best prophylaxis for the prevention of infectious diseases, including coronavirus disease 2019. However, the efficacy of vaccines and onset of adverse reactions vary among individuals. Circulating extracellular vesicles (EVs) regulate the immune responses after vaccination by delivering microRNAs (miRNAs) to myeloid and lymphoid cells. Among these, miR-192 levels in serum EVs increase with aging, in an IL-6-dependent manner, reducing excessive IL-6 expression in aged mice, creating a negative feedback loop. Excessive IL-6 expression reduces vaccination efficacy in aged mice, while EV miR-192 improves efficacy in these aged mice as well, making this miRNA an interesting focus of study. miR-21 levels in serum EVs also increase with aging, and regulates the expression of IL-12 required for Th1 responses; therefore, EV miR-21 is expected to regulate vaccine efficacy. miR-451a, another important miRNA, is abundant in serum EVs and controls the expression of cytokines, such as type I interferon and IL-6. However, levels differ among individuals and correlate with local inflammatory symptoms experienced after a seasonal flu vaccination. These findings suggest the importance of EV miRNAs as a tool to improve vaccine efficacy and also as biomarkers to predict the immune response and adverse reactions after vaccinations.

Emerging Role of MiR-192-5p in Human Diseases

MicroRNAs (miRNAs) are a type of small non-coding RNAs that play an essential role in numerous biological processes by regulating the post-transcriptional expression of target genes. Recent studies have demonstrated that miR-192-5p, a member of the miR-192 family, partakes in several human diseases, especially various cancers, including cancers of the lung, liver, and breast. Importantly, the levels of miR-192-5p are abundant in biofluids, including the serum and urine, and the exosomal levels of miR-192-5p in circulation can aid in the diagnosis and prognosis of various diseases, such as chronic hepatitis B (CHB) infection disease. Notably, recent studies suggest that miR-192-5p is regulated by long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs). However, there are no comprehensive overviews on the role of miR-192-5p in human diseases. This review discusses the significant studies on the role of miR-192-5p in various human diseases, with special emphasis on the diseases of the respiratory and digestive systems.

Compound C Protects Against Cisplatin-Induced Nephrotoxicity Through Pleiotropic Effects

AICAR (Acadesine/AICA riboside) as an activator of AMPK, can protect renal tubular cells from cisplatin induced apoptosis. But in our experiment, the dorsomorphin (compound C, an inhibitor of AMPK) also significantly reduced cisplatin induced renal tubular cells apoptosis. Accordingly, we tested whether compound C can protect cisplatin-induced nephrotoxicity and the specific mechanism. Here, we treated Boston University mouse proximal tubular cells (BUMPT-306) with cisplatin and/or different dosages of AICAR (Acadesine/AICA riboside) or compound C to confirm the effect of AICAR and compound C in vitro. The AMPK-siRNA treated cells to evaluate whether the protective effect of compound C was through inhibiting AMPK. Male C57BL/6 mice were used to verify the effect of compound C in vivo. Both compound C and AICAR can reduce renal tubular cells apoptosis in dose-dependent manners, and compound C decreased serum creatinine and renal tubular injury induced by cisplatin. Mechanistically, compound C inhibited P53, CHOP and p-IREα during cisplatin treatment. Our results demonstrated that compound C inhibited AMPK, but the renal protective effects of compound C were not through AMPK. Instead, compound C protected cisplatin nephrotoxicity by inhibiting P53 and endoplasmic reticulum (ER) stress. Therefore, compound C may protect against cisplatin-induced nephrotoxicity through pleiotropic effects.

P53/miR-154 Pathway Regulates the Epithelial-Mesenchymal Transition in Glioblastoma Multiforme Cells by Targeting TCF12

PURPOSE

Glioblastoma multiforme (GBM) is an aggressive brain tumor with a rather short survival time. Mutation of p53 has been observed and reported to play critical roles in the progression of GBM. However, the pathological mechanisms are still unclear. This study was designed to identify the role of miR-154 in mediating the biological functions of p53 in glioblastoma multiforme.

METHODS

In the current study, the expression of miR-154 in GBM tissue samples and cell lines with wt-p53 or mutant p53 was evaluated. The functions of miR-154 in tumor migration, invasion and epithelial-mesenchymal transition were analyzed in vitro. A luciferase reporter assay was used to identify the target of miR-154.

RESULTS

We found that expression of miR-154 was much lower in patient tissues with mutant p53. Further study revealed that p53 was a transcription factor of miR-154 and that the R273H mutation led to its inactivation. In addition, overexpression of miR-154 remarkably suppressed cell migration, invasion and EMT in vitro and tumor growth in vivo. Moreover, TCF12 was proven to be a direct target of miR-154, and the tumor suppressive effect of miR-154 was reversed by TCF12.

CONCLUSION

Overall, miR-154, which was regulated by wt-p53, inhibited migration, invasion and EMT of GBM cells by targeting TCF12, indicating that miR-154 may act as a biomarker and that the p53/miR-154/TCF12 pathway could be a potential therapeutic target for GBM.

Knockdown of lncRNA ANRIL suppresses the production of inflammatory cytokines and mucin 5AC in nasal epithelial cells via the miR-15a-5p/JAK2 axis

The incidence of allergic rhinitis (AR) is increasing worldwide. Human nasal epithelial cells (HNECs) are the key cells in the occurrence of AR. Antisense non-coding RNA in the INK4 locus (ANRIL) was discovered to be involved in the progression of AR. However, the mechanism by which ANRIL mediates the progression of AR remains to be determined. The present study aimed to further explore the mechanism by which ANRIL regulates AR. Thereby, HNECs were treated with IL-13 to mimic AR in vitro. The mRNA expression levels of ANRIL, microRNA (miR)-15a-5p, JAK2, mucin 5AC (MUC5AC), granulocyte-macrophage colony-stimulating factor (GM-CSF) and eotaxin-1, and protein expression levels of JAK2, STAT3 and phosphorylated-STAT3 in HNECs were analyzed using reverse transcription-quantitative PCR and western blotting, respectively. ELISAs were used to detect the secretory levels of inflammatory cytokines and mucin in cell supernatants. In addition, a dual luciferase reporter assay was used to confirm the downstream target of ANRIL and the target gene of miR-15a-5p. The results revealed that the secretory levels of eotaxin-1, GM-CSF and MUC5AC were significantly upregulated by IL-13 in the supernatant of HNECs. The expression levels of ANRIL and JAK2 were also upregulated in IL-13-induced HNECs, while the expression levels of miR-15a-5p were downregulated. In addition, ANRIL was identified to bind to miR-15a-5p. The IL-13-induced upregulation of eotaxin-1, GM-CSF and MUC5AC mRNA expression and secretory levels was significantly inhibited by the genetic knockdown of ANRIL, while the miR-15a-5p inhibitor effectively reversed this effect. JAK2 was also discovered to be directly targeted by miR-15a-5p. The overexpression of JAK2 significantly suppressed the therapeutic effect of miR-15a-5p mimics on IL-13-induced inflammation in vitro. In conclusion, the findings of the present study suggested that the genetic knockdown of ANRIL may suppress the production of inflammatory cytokines and mucin in IL-13-treated HNECs via regulation of the miR-15a-5p/JAK2 axis. Thus, ANRIL may serve as a novel target for AR treatment.

MBD2 Mediates Septic AKI through Activation of PKCη/p38MAPK and the ERK1/2 Axis

Our previous study demonstrated that the methyl-CpG-binding domain protein 2 (MBD2) mediates vancomycin (VAN)-induced acute kidney injury (AKI). However, the role and regulation of MBD2 in septic AKI are unknown. Herein, MBD2 was induced by lipopolysaccharide (LPS) in Boston University mouse proximal tubules (BUMPTs) and mice. For both in vitro and in vivo experiments, we showed that inhibition of MBD2 by MBD2 small interfering RNA (siRNA) and MBD2-knockout (KO) substantially improved the survival rate and attenuated both LPS and cecal ligation and puncture (CLP)-induced AKI, renal cell apoptosis, and inflammatory factor production. Global genetic expression analyses and in vitro experiments suggest that the expression of protein kinase C eta (PKCη), caused by LPS, is markedly suppressed in MBD2-KO mice and MBD2 siRNA, respectively. Mechanistically, chromatin immunoprecipitation (ChIP) analysis indicates that MBD2 directly binds to promoter region CpG islands of PKCη via suppression of promoter methylation. Furthermore, PKCη siRNA improves the survival rate and attenuates LPS-induced BUMPT cell apoptosis and inflammatory factor production via inactivation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK)1/2, which were further verified by PKCη siRNA treatment in CLP-induced AKI. Finally, MBD2-KO mice exhibited CLP-induced renal cell apoptosis and inflammatory factor production by inactivation of PKCη/p38MAPK and ERK1/2 signaling. Taken together, the data indicate that MBD2 mediates septic-induced AKI through the activation of PKCη/p38MAPK and the ERK1/2 axis. MBD2 represents a potential target for treatment of septic AKI.

Acute Kidney Injury in Septic Patients Treated by Selected Nephrotoxic Antibiotic Agents-Pathophysiology and Biomarkers-A Review

Acute kidney injury is a common complication in critically ill patients with sepsis and/or septic shock. Further, some essential antimicrobial treatment drugs are themselves nephrotoxic. For this reason, timely diagnosis and adequate therapeutic management are paramount. Of potential acute kidney injury (AKI) biomarkers, non-protein-coding RNAs are a subject of ongoing research. This review covers the pathophysiology of vancomycin and gentamicin nephrotoxicity in particular, septic AKI and the microRNAs involved in the pathophysiology of both syndromes. PubMED, UptoDate, MEDLINE and Cochrane databases were searched, using the terms: biomarkers, acute kidney injury, antibiotic nephrotoxicity, sepsis, miRNA and nephrotoxicity. A comprehensive review describing pathophysiology and potential biomarkers of septic and toxic acute kidney injury in septic patients was conducted. In addition, five miRNAs: miR-15a-5p, miR-192-5p, miR-155-5p, miR-486-5p and miR-423-5p specific to septic and toxic acute kidney injury in septic patients, treated by nephrotoxic antibiotic agents (vancomycin and gentamicin) were identified. However, while these are at the stage of clinical testing, preclinical and clinical trials are needed before they can be considered useful biomarkers or therapeutic targets of AKI in the context of antibiotic nephrotoxicity or septic injury.

Vancomycin-Induced Kidney Injury: Animal Models of Toxicodynamics, Mechanisms of Injury, Human Translation, and Potential Strategies for Prevention

Vancomycin is a recommended therapy in multiple national guidelines. Despite the common use, there is a poor understanding of the mechanistic drivers and potential modifiers of vancomycin-mediated kidney injury. In this review, historic and contemporary rates of vancomycin-induced kidney injury (VIKI) are described, and toxicodynamic models and mechanisms of toxicity from preclinical studies are reviewed. Aside from known clinical covariates that worsen VIKI, preclinical models have demonstrated that various factors impact VIKI, including dose, route of administration, and thresholds for pharmacokinetic parameters. The degree of acute kidney injury (AKI) is greatest with the intravenous route and higher doses that produce larger maximal concentrations and areas under the concentration curve. Troughs (i.e., minimum concentrations) have less of an impact. Mechanistically, preclinical studies have identified that VIKI is a result of drug accumulation in proximal tubule cells, which triggers cellular oxidative stress and apoptosis. Yet, there are several gaps in the knowledge that may represent viable targets to make vancomycin therapy less toxic. Potential strategies include prolonging infusions and lowering maximal concentrations, administration of antioxidants, administering agents that decrease cellular accumulation, and reformulating vancomycin to alter the renal clearance mechanism. Based on preclinical models and mechanisms of toxicity, we propose potential strategies to lessen VIKI.

New insights into the vancomycin-induced nephrotoxicity using in vitro metabolomics combined with physiologically based pharmacokinetic modeling

Vancomycin is a first-line treatment for invasive infections caused by multidrug-resistant gram-positive bacteria. However, vancomycin-induced nephrotoxicity is an increasing burden, particularly in patients with complex life-threatening conditions. Vancomycin-induced nephrotoxicity associated with clinically relevant exposure on the target site has not been well defined. This study aimed to acquire the concentration of vancomycin in the renal tubules and kidneys in humans using physiologically based pharmacokinetic (PBPK) modeling and simulation. Based upon the exposure of vancomycin in the renal tubule, the toxicity of vancomycin in human renal proximal tubular epithelial cells was examined with the XTT assay and in vitro metabolomics analysis. A rat PBPK model predicting plasma and kidney concentration-time profiles of vancomycin matched the observed behavior after a single administration of 10 mg/kg. The concentration of vancomycin in renal tubules was about 40-50 times higher than that in plasma. The human PBPK model transferred from the rat model predicted renal tubule concentrations of vancomycin as 316.1-2136.6 μg/mL at 500 mg every 6 hours, and 199.0-3932.5 μg/mL at 1000 mg every 12 hours. Vancomycin showed significant nephrotoxicity at 4 mg/mL in XTT assessment. In total, 11 lysophosphatidylcholines and one lysophosphatidylethanolamine were identified by metabolomics analysis. The concentration-dependent increase was evident in the release of lysophospholipids after vancomycin treatment (0.125-4 mg/mL) for 24 hours. Our study revealed the relationship between the exposure of vancomycin in the kidney and toxicity of vancomycin at clinically relevant concentrations achieved from a mechanical PBPK model. A series of lysophospholipids as potential metabolic markers of renal toxicity were identified.

Oral delivery of nanoparticle urolithin A normalizes cellular stress and improves survival in mouse model of cisplatin-induced AKI

The popular anticancer drug cisplatin causes many adverse side effects, the most serious of which is acute kidney injury (AKI). Emerging evidence from laboratory and clinical studies suggests that the AKI pathogenesis involves oxidative stress pathways; therefore, regulating such pathways may offer protection. Urolithin A (UA), a gut metabolite of the dietary tannin ellagic acid, possesses antioxidant properties and has shown promise in mouse models of AKI. However, therapeutic potential of UA is constrained by poor bioavailability. We aimed to improve oral bioavailability of UA by formulating it into biodegradable nanoparticles that use a surface-conjugated ligand targeting the gut-expressed transferrin receptor. Nanoparticle encapsulation of UA led to a sevenfold enhancement in oral bioavailability compared with native UA. Treatment with nanoparticle UA also significantly attenuated the histopathological hallmarks of cisplatin-induced AKI and reduced mortality by 63% in the mouse model. Expression analyses indicated that nanoparticle UA therapy coincided with oxidative stress mitigation and downregulation of nuclear factor erythroid 2-related factor 2- and P53-inducible genes. Additionally, normalization of miRNA (miR-192-5p and miR-140-5p) implicated in AKI, poly(ADP-ribose) polymerase 1 levels, antiapoptotic signaling, intracellular NAD+, and mitochondrial oxidative phosphorylation were observed in the treatment group. Our findings suggest that nanoparticles greatly increase the oral bioavailability of UA, leading to improved survival rates in AKI mice, in part by reducing renal oxidative and apoptotic stress.

Oral delivery of nanoparticle urolithin A normalizes cellular stress and improves survival in mouse model of cisplatin-induced AKI

The popular anticancer drug cisplatin causes many adverse side effects, the most serious of which is acute kidney injury (AKI). Emerging evidence from laboratory and clinical studies suggests that the AKI pathogenesis involves oxidative stress pathways; therefore, regulating such pathways may offer protection. Urolithin A (UA), a gut metabolite of the dietary tannin ellagic acid, possesses antioxidant properties and has shown promise in mouse models of AKI. However, therapeutic potential of UA is constrained by poor bioavailability. We aimed to improve oral bioavailability of UA by formulating it into biodegradable nanoparticles that use a surface-conjugated ligand targeting the gut-expressed transferrin receptor. Nanoparticle encapsulation of UA led to a sevenfold enhancement in oral bioavailability compared with native UA. Treatment with nanoparticle UA also significantly attenuated the histopathological hallmarks of cisplatin-induced AKI and reduced mortality by 63% in the mouse model. Expression analyses indicated that nanoparticle UA therapy coincided with oxidative stress mitigation and downregulation of nuclear factor erythroid 2-related factor 2- and P53-inducible genes. Additionally, normalization of miRNA (miR-192-5p and miR-140-5p) implicated in AKI, poly(ADP-ribose) polymerase 1 levels, antiapoptotic signaling, intracellular NAD+, and mitochondrial oxidative phosphorylation were observed in the treatment group. Our findings suggest that nanoparticles greatly increase the oral bioavailability of UA, leading to improved survival rates in AKI mice, in part by reducing renal oxidative and apoptotic stress.

Coordination of miR-192 and miR-22 in p53-Mediated Cell Fate Decision

p53-targeted microRNAs (miRNAs) markedly affect cellular response to DNA damage. These miRNAs may contribute to either cell cycle arrest or apoptosis induction. However, how these miRNAs coordinate to modulate the decision between cell survival and death remains less understood. Here, we developed an integrated model of p53 signaling network to investigate how p53-targeted miR-192 and miR-22 modulate cellular outcome in response to DNA damage. By numerical simulations, we found that p53 is activated progressively depending on the extent of DNA damage. Upon moderate damage, p53 rises to medium levels and induces miR-192 to promote its own activation, facilitating p21 induction and cell cycle arrest. Upon severe damage, p53 reaches high levels and is fully activated due to phosphatase and tensin homolog (PTEN) induction. As a result, it transactivates miR-22 to repress p21 expression and activate E2F1, resulting in apoptosis. Therefore, miR-192 promotes primary activation of p53, while miR-22 promotes apoptosis by downregulating p21. This work may advance the understanding of the mechanism for cell fate decision between life and death by p53-inducible miRNAs.

Protective Effect of Hesperidin on Sodium Arsenite-Induced Nephrotoxicity and Hepatotoxicity in Rats

The present study was conducted to investigate the protective effects of hesperidin (HSP) against sodium arsenite (SA)-induced nephrotoxicity and hepatotoxicity in rats. Thirty-five male Sprague Dawley rats were divided into five groups as follows: control, HSP, SA, SA + HSP 100, and SA + HSP 200. Rats were orally gavaged with SA (10 mg/kg body weight) and HSP (100 and 200 mg/kg body weight) for 15 days. SA increased oxidative damage by decreasing antioxidant enzyme activities, such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx), and glutathione (GSH) level and increasing malondialdehyde (MDA) level in the kidney and liver tissues. In addition, it increased serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and serum urea and creatinine levels. Furthermore, SA caused inflammation, apoptosis, and oxidative DNA damage by increasing tumor necrosis factor-α (TNF-α), nuclear factor kappa B (NF-κB), interleukin-1β (IL-1β), cysteine aspartate-specific protease-3 (caspase-3), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in the kidney and liver tissues and by increasing liver p53 and kidney interleukin-6 (IL-6) expressions. In other words, HSP administration reduced apoptosis, oxidative stress, inflammation, and oxidative DNA damage significantly in SA-induced kidney and liver tissues depending on dose. In this study, it was seen that HSP showed a protective effect against SA-induced kidney and liver toxicity.

EGFR drives the progression of AKI to CKD through HIPK2 overexpression

The molecular mechanism underlying the transition of acute kidney injury (AKI) to chronic kidney disease (CKD) induced by vancomycin (VAN) remains largely unknown. Methods: The mice model of VAN drives AKI to CKD was developed to investigate the role and molecular mechanism of epidermal growth factor receptor (EGFR). The EGF receptor mutant (Wa-2) mice and gefitinib were used to inactivation of EGFR. The homeodomain interacting protein kinase 2 (HIPK2) siRNA was applied to silence of HIPK2. Human proximal tubular epithelial cells (HK-2) were used to explore the molecular regulation methanism of EGFR. ChIp analysis was used to investigate if STAT3 interaction with the promoter of HIPK2. Results: A novel VAN-induced AKI mouse model was established for the first time. Moreover, the expression levels collagen I&IV, α-SMA, p-EGFR and the expression of HIPK2 proteins were upregulated in this model. Interestingly, AKI caused by VAN was markedly attenuated in waved-2 mice at the early stage, as evidenced by the suppression of renal dysfunction, renal cell apoptosis and caspase3 activation. In the latter stage, renal fibrosis and inflammation were significantly ameliorated in Wa-2 mice, accompanied by the downregulation of profibrotic molecules and F4/80. Besides, the expression levels of HIPK2 and p-STAT3 were suppressed in Wa-2 mice during VAN-induced transition of AKI to CKD. In addition, renal fibrosis and inflammation, profibrotic molecules, and EGFR/STAT3/HIPK2 signaling were ameliorated by gefitinib treatment after VAN-induced AKI. These results were consistent with the findings of Wa-2 mice. EGFR/STAT3 signaling mediated VAN-induced HIPK2 expression in HK-2 cells. ChIp analysis revealed that STAT3 directly bound to the promoter region of HIPK2. Finally, inhibition of HIPK2 attenuated the VAN drove the progression of AKI to CKD. Conclusion: These data suggest that EGFR plays an important role in VAN-driven progression of AKI to CKD.

Both Peripheral Blood and Urinary miR-195-5p, miR-192-3p, miR-328-5p and Their Target Genes PPM1A, RAB1A and BRSK1 May Be Potential Biomarkers for Membranous Nephropathy

Background

To identify noninvasive diagnostic biomarkers for membranous nephropathy (MN).

Material/Methods

The mRNA microarray datasets GSE73953 using peripheral blood mononuclear cells (PBMCs) of 8 membranous nephropathy patients and 2 control patients; and microRNAs (miRNA) microarray dataset GSE64306 using urine sediments of 4 membranous nephropathy patients and 6 control patients were downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) were respectively identified from PBMCs and urine sediments of membranous nephropathy patients, followed with functional enrichment analysis, protein-protein interaction (PPI) analysis, and miRNA-target gene analysis. Finally, the DEGs and the target genes of DEMs were overlapped to obtain crucial miRNA-mRNA interaction pairs for membranous nephropathy.

Results

A total of 1246 DEGs were identified from PBMCs samples, among them upregulated CCL5 was found to be involved in the chemokine signaling pathway, and BAX was found to be apoptosis related; while downregulated PPM1A and CDK1 were associated with the MAPK signaling pathway and the p53 signaling pathway, respectively. The hub role of CDK1 (degree=18) and CCL5 (degree=12) were confirmed after protein-protein interaction network analysis in which CKD1 could interact with RAB1A. A total of 28 DEMs were identified in urine sediments. The 276 target genes of DEMs were involved in cell cycle arrest (PPM1A) and intracellular signal transduction (BRSK1). Thirteen genes were shared between the DEGs in PMBCs and the target genes of DEMs in urine sediments, but only hsa-miR-192-3p-RAB1A, hsa-miR-195-5p-PPM1A, and hsa-miR-328-5p-BRSK1 were negatively related in their expression level.

Conclusions

Both peripheral blood and urinary miR-195-5p, miR-192-3p, miR-328-5p, and their target genes PPM1A, RAB1A, and BRSK1 may be potential biomarkers for membranous nephropathy by participating in inflammation and apoptosis.

Atg7 mediates renal tubular cell apoptosis in vancomycin nephrotoxicity through activation of PKC-δ

Recent studies have shown that autophagy exhibits a renoprotective role in various models of acute kidney injury (AKI). However, its role in vancomycin (Van)-induced AKI remains largely unclarified. This study was the first to indicate that autophagy was rapidly activated in both human kidney-2 cells and renal tissues, and mammalian target of rapamycin (mTOR) was inactivated via the suppression of ERK1/2 and mTOR during Van treatment. Interestingly, for both in vitro and in vivo experiments, the suppression of autophagy via chloroquine and PT-Atg7-KO significantly ameliorated Van-induced kidney injury and renal tubular cell apoptosis. Global gene expression analysis indicated that the expression levels of 6159 genes were induced by Van treatment in the kidney cortical tissues of PT-Atg7 wild-type mice, and 18 of them were notably suppressed in PT-Atg7-KO mice. These 18 genes were further classified as programmed cell death, protein binding, signal transduction, E3 ubiquitin ligase, nucleoside diphosphate kinase activity, and E1-like activating enzyme. Unexpectedly, following Van treatment, PKC-δ expression was found to be highest among the 4 genes related to cell death, which was remarkably suppressed in vitro and in PT-Atg7-KO mice. In addition, Atg7 could induce renal cell apoptosis during Van treatment via binding to PKC-δ. Likewise, the inhibition of PKCδ ameliorated Van-induced apoptosis in human kidney-2 cells and kidney tissues. Furthermore, the data showed that PT-Atg7-KO exerted a renoprotective effect against Van-induced nephrotoxicity, but this effect was lost after injection with myc-tagged PKCδ. Taken altogether, these results indicate that Van induces autophagy by suppressing the activation of the ERK1/2 and mTOR signaling pathway. In addition, Atg7 mediates Van-induced AKI through the activation of PKCδ. In sum, autophagy inhibition may serve as a novel therapeutic target for treating nephrotoxic AKI induced by Van.-Xu, X., Pan, J., Li, H., Li, X., Fang, F., Wu, D., Zhou, Y., Zheng, P., Xiong, L., Zhang, D. Atg7 mediates renal tubular cell apoptosis in vancomycin nephrotoxicity through activation of PKC-δ.

Time-dependent p53 inhibition determines senescence attenuation and long-term outcome after renal ischemia-reperfusion

Inhibition of p53 has been shown to be an efficient strategy for ameliorating kidney ischemia-reperfusion (I/R) injury in experimental models. The therapeutic value of p53 siRNA-based inhibition for I/R in renal transplantation is currently being evaluated in clinical studies. While the major rationale for these studies is the suppression of proapoptotic properties, there are more equally important injury response pathways regulated by p53. A p53-dependent pathway shown to be crucial for renal long-term outcome is cellular senescence. In this study, we tested the hypothesis that p53 siRNA reduces I/R-induced senescence and thereby improves kidney outcome. By comparing the impact of different treatment durations in a mouse model of renal I/R, we found that repetitive administration of p53 siRNA during the first 14 days after I/R reduced the senescence load and ameliorated the postischemic phenotype. Prolonged application of p53 siRNA over a 26-day period after I/R, however, did not provide any additional benefit for senescence reduction but reversed some of the renoprotective effects of the early treatment. These data suggest a time-dependent role of p53 activity supporting the current therapeutic concept of a short-term inhibition, while advocating against a prolonged treatment after I/R.

P53 in kidney injury and repair: Mechanism and therapeutic potentials

Acute kidney injury (AKI) is a major kidney disease with poor clinical outcome. Besides its acute consequence of high mortality, AKI may also contribute significantly to the occurrence and progression of chronic kidney diseases (CKD). Accumulating evidence has demonstrated that maladaptive and incomplete kidney repair after AKI leads to the development of renal fibrosis and, ultimately, CKD. p53, a well-known tumor suppressor, plays a critical role in AKI and subsequent kidney repair through the regulation of various cell biologic processes, including apoptosis, cell cycle arrest, and autophagy. Despite the notable progress in deciphering the involvement of p53 in kidney injury and repair, the underlying mechanisms of p53 in these pathological processes remain largely unknown. Further investigation in this area is essential for the application of p53 as therapeutic target to prevent and treat AKI or impede its progression to CKD. In this review, we summarize the recent advances in understanding p53 regulation of AKI and kidney repair, pinpoint the potential of p53 as a therapeutic target, and present future research interests and directions.

FGF21 is induced in cisplatin nephrotoxicity to protect against kidney tubular cell injury

Cisplatin, a widely used cancer therapy drug, induces nephrotoxicity or acute kidney injury (AKI), but the underlying mechanism remains unclear, and renal protective approaches are not available. Fibroblast growth factor (FGF)21 is an endocrine factor that regulates glucose uptake, metabolism, and energy expenditure. However, recent work has also implicated FGF21 in cellular stress response under pathogenic conditions. The role and regulation of FGF21 in AKI are unclear. Here, we show that FGF21 was dramatically induced during cisplatin treatment of renal tubular cells in vitro and mouse kidneys in vivo. The inductive response was suppressed by pifithrin (a pharmacological inhibitor of P53), suggesting a role of P53 in FGF21 induction. In cultured renal tubular cells, knockdown of FGF21 aggravated cisplatin-induced apoptosis, whereas supplementation of recombinant FGF21 was protective. Consistently, recombinant FGF21 alleviated cisplatin-induced kidney dysfunction, tissue damage, and tubular apoptosis in mice. Mechanistically, FGF21 suppressed P53 induction and activation during cisplatin treatment. Together, these results indicate that FGF21 is induced during cisplatin nephrotoxicity to protect renal tubules, and recombinant FGF21 may have therapeutic potential.-Li, F., Liu, Z., Tang, C., Cai, J., Dong, Z. FGF21 is induced in cisplatin nephrotoxicity to protect against kidney tubular cell injury.

Genome-wide Profiling of Urinary Extracellular Vesicle microRNAs Associated With Diabetic Nephropathy in Type 1 Diabetes

Introduction

Diabetic nephropathy (DN) is a form of progressive kidney disease that often leads to end-stage renal disease (ESRD). It is initiated by microvascular complications due to diabetes. Although microalbuminuria (MA) is the earliest clinical indication of DN among patients with type 1 diabetes (T1D), it lacks the sensitivity and specificity to detect the early onset of DN. Recently, microRNAs (miRNAs) have emerged as critical regulators in diabetes as well as various forms of kidney disease, including renal fibrosis, acute kidney injury, and progressive kidney disease. Additionally, circulating extracellular miRNAs, especially miRNAs packaged in extracellular vesicles (EVs), have garnered significant attention as potential noninvasive biomarkers for various diseases and health conditions.

Methods

As part of the University of Pittsburgh Epidemiology of Diabetes Complications (EDC) study, urine was collected from individuals with T1D with various grades of DN or MA (normal, overt, intermittent, and persistent) over a decade at prespecified intervals. We isolated EVs from urine and analyzed the small-RNA using NextGen sequencing.

Results

We identified a set of miRNAs that are enriched in urinary EVs compared with EV-depleted samples, and identified a number of miRNAs showing concentration changes associated with DN occurrence, MA status, and other variables, such as hemoglobin A1c levels.

Conclusion

Many of the miRNAs associated with DN occurrence or MA status directly target pathways associated with renal fibrosis (including transforming growth factor-β and phosphatase and tensin homolog), which is one of the major contributors to the pathology of DN. These miRNAs are potential biomarkers for DN and MA.

MBD2 upregulates miR-301a-5p to induce kidney cell apoptosis during vancomycin-induced AKI

Despite DNA methylation occurred in acute kidney injury (AKI), how it influenced progression of AKI remains unclear. Methyl-CpG-binding domain protein 2 (MBD2), a protein readers of methylation, was used to analyze the impact of DNA methylation on vancomycin (VAN)-induced AKI. Here, in cultured human kidney tubular epithelial cells (HK-2), we show that knockdown of MBD2 by siRNA attenuated VAN-induced apoptosis, caspase activity, and the expression of BAX and cleaved caspase 3. Interestingly, knockdown of MBD2 by siRNA was associated with the suppression of miR-301a-5p. Mechanistic studies confirmed MBD2 binds to these methylated CpG elements of miR-301a-5p promoter, and then activates miR-301a-5p promoter by suppressing methylation. Furthermore, anti-miR-301a-5p significantly blocked VAN-induced apoptosis and caspase activity in HK-2 cells, which was accompanied by downregulation of p53, and upregulation of MITF, HDGF and MDM-4 together. The latter genes were further identified as target genes of miR-301a-5p, and silencing of MDM-4 promoted p53 accumulation. In vivo, mice with MBD2 knockout (MBD2-KO) were counteracted to VAN-induced AKI, indicated by the analysis of renal function, histology, apoptosis and inflammation. MBD2-KO also significantly suppressed the expression of miR-301a-5p, p53, BAX and cleaved caspase 3, and restored the expression of MDM-4, MITF and HDGF. Finally, in vivo inhibition of miR-301a-5p also ameliorated VAN-induced AKI. Together, these results show the novel MBD2/miR-301a-5p/MITF, HDGF and MDM-4/p53 pathway in VAN-induced AKI.

Genetic or pharmacologic inhibition of EGFR ameliorates sepsis-induced AKI

Despite recent studies have demonstrated that the EGF receptor (EGFR) activation provided a renoprotective role during ischemic and folic acid-induced AKI, the role and regulation mechanism of EGFR in septic AKI remains unclear. Here, gefitinib, a highly selective EGFR inhibitor, abrogated LPS-induced phosphorylation of EGFR, ERK1/2, and STAT3 as well as expression of COX, eNOS, and proinflammatory cytokines in HK-2 cells. In addition, c-Src is an upstream of EGFR signaling pathway and mediates LPS-induced EGFR transactivation. In vivo, either gefitinib or genetic approaches (Wave-2 mutant mice, which have reduced EGFR tyrosine kinase activity) protected against LPS or cecal ligation and puncture (CLP) induced AKI respectively. Interestingly, the beneficial effects of gefitinib or genetic approaches were accompanied by the dephosphorylation of EGFR, ERK1/2, and STAT3, the down regulation of expression of COX, eNOS, macrophage infiltration, proinflammatory cytokines production and the renal cell apoptosis. Furthermore, mRNA array results indicated that gene families involved in cell death, inflammation, proliferation and signal transduction were down regulated in Wave-2 (Wa-2) mice. Take together, these data suggest that EGFR may mediate renal injury by promoting production of inflammatory factors and cell apoptosis. Inhibition of EGFR may have therapeutic potential for AKI during endotoxemia.