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.

Discovery and verification of mmu_Circ_26986/hsa_Circ_0072463 as a potential biomarker and intervention target for sepsis-associated acute kidney injury.

Approximately 60% of septic patients developed acute kidney injury (AKI). The mortality rate of septic AKI (SA-AKI) is two to three times higher than that of septic without AKI (SA-non-AKI). The actual functions and mechanisms of CircRNAs in the pathophysiology of SA-AKI remain incompletely understood. Herein, we observed that the mmu_Circ_26986 could be induced by lipopolysaccharide (LPS) and cecum ligation and puncture (CLP) in BUMPT cell line and C57BL/6 mouse kidney, respectively. Functionally, mmu_Circ_26986 suppressed BUMPT cell apoptosis induced by LPS. Mechanistically, mmu_Circ_26986 sponged miRNA-29b-1-5p to upregulate the expression of PAK7. Overexpression of mmu_Circ_26986 ameliorated the progression of CLP-stimulated AKI through miRNA-29b-1-5p/PAK7 axis. In addition, we found that hsa_Circ_0072463, homologous to mmu_Circ_26986, suppressed LPS-induced HK-2 cells apoptosis via regulation of miRNA-29b-1-5p/PAK7 axis. Furthermore, sepsis patients with AKI had a higher level of hsa_Circ_0072463 compared to those without AKI. The sensitivity, specificity and AUC of hsa_Circ_0072463 were 78.8%, 87.9% and 0.866, respectively. Spearman's test indicated a noticeable positive correlation between plasma hsa_Circ_0072463 and serum creatinine in sepsis patients (r = 0.725). In summary, this study reveals that the mmu_Circ_26986/hsa_Circ_0072463 miRNA-29b-1-5p/PAK7 axis mediates septic AKI, and hsa_Circ_0072463 is a potential diagnostic marker for septic AKI.

The mmu_circ_003062, hsa_circ_0075663/miR-490-3p/CACNA1H axis mediates apoptosis in renal tubular cells in association with endoplasmic reticulum stress following ischemic acute kidney injury.

BACKGROUND: While recent studies have suggested a potential involvement of circRNAs in acute kidney injury (AKI) after ischemia, mmu_circ_003062 role is undetermined. METHODS: The levels of mmu_circ_003062, miR-490-3p, CACNA1H, GRP78, CHOP and hsa_circ_0075663 were detected by Relative qPCR in Boston University mouse proximal tubule (BUMPT) cells, mouse kidneys, and human renal tubular epithelial (HK-2) cells. Moreover, the levels of hsa_circ_0075663 in serum and urine of patients with AKI following cardiopulmonary resuscitation (CPR) were detected by absolute quantitative PCR. Western blot was used to detect the relative expression of the protein. The function and regulatory mechanism of mmu_circ_003062 and hsa_circ_0075663 were investigated through a series of in vitro and in vivo experiments, including bioinformatic prediction, luciferase reporter assays, FISH, FCM, TUNEL staining, and H&E staining. RESULTS: It was found that mmu_circ_003062, hsa_circ_0075663 mediated apoptosis after ischemia/reperfusion (I/R) by interaction with miR-490-3p to enhance CACNA1H expression, thereby leading to the upregulation of endoplasmic reticulum stress (ERS)-relevant proteins GRP78 and CHOP. Ultimately, mmu_circ_003062 downregulation significantly ameliorated ischemic AKI by modulating the miR-490-3p/CACNA1H/GRP78 and CHOP pathway. Furthermore, the plasma and urinary levels of hsa_circ_0075663 in patients with AKI following CPR were significantly higher than non-AKI patients, exhibited a strongly correlation with serum creatinine. CONCLUSION: The involvement of mmu_circ_003062, hsa_circ_0075663/miR-490-3p/CACNA1H/GRP78 and CHOP axis is significant in the development of ischemic AKI. Moreover, hsa_circ_0075663 has potential as an early diagnostic biomarker.

Discovery of PRDM16-Mediated TRPA1 Induction as the Mechanism for Low Tubulo-Interstitial Fibrosis in Diabetic Kidney Disease.

The pathogenesis of Diabetic kidney disease(DKD) involves pathological changes in both tubulo-interstitium and the glomerulus. Surprisingly, tubulo-interstitial fibrosis (TIF), does not develop significantly until the late stage of DKD. Here, it is demonstrated that PR domain-containing 16 (PRDM16) is a key to the low level of TIF in DKD. In the experiments, PRDM16 is upregulated in high glucose-treated renal tubular cells, DKD mouse kidneys, and renal biopsy of human DKD patients via activation of NF-κB signal pathway. High glucose-induced expression of fibrotic proteins in renal tubular cells is suppressed by PRDM16. Mechanistically, PRDM16 bound to the promotor region of Transient receptor potential ankyrin 1 (TRPA1) to transactivate its expression and then suppressed MAPK (P38, ERK1/2) activation and downstream expression of TGF-ß1. Knockout of PRDM16 from kidney proximal tubules in mice blocked TRPA1 expression and enhanced MAPK activation, TGF-ß1 production, TIF development, and DKD progression, whereas knock-in of PRDM16 has opposite effects. In addition, overexpression of PRDM16 or its induction by formononetin ameliorated renal dysfunction and fibrosis in db/db diabetic mice. Finally, the above finding are detected in renal biopsies of DKD patients. Together, these results unveil PRDM16/TRPA1 as the mechanism responsible for the low level of TIF in the early stage of DKD by suppressing and TGF-ß1 expression.

Inhibition of METTL3 alleviated LPS-induced alveolar epithelial cell apoptosis and acute lung injury via restoring neprilysin expression.

AIMS: To investigate the role and mechanisms of methyltransferase-like 3 (METTL3) in the pathogenesis of lipopolysaccharide (LPS)-induced acute lung injury (ALI). MAIN METHODS: LPS intratracheally instillation was applied in alveolar epithelial cell METTL3 conditional knockout (METTL3-CKO) mice and their wild-type littermates. In addition, METTL3 inhibitor STM2457 was used. LPS treatment on mouse lung epithelial 12 (MLE-12) cell was applied to establish an in vitro model of LPS-induced ALI. H&E staining, lung wet-to-dry ratio, and total broncho-alveolar lavage fluid (BALF) concentrations were used to evaluate lung injury. Overall, the m6A level was determined with the m6A RNA Methylation Quantification Kit and dot blot assay. Expression of METTL3 and neprilysin were measured with immunohistochemistry, immunofluorescence, immunofluorescence-fluorescence in situ hybridization, and western blot. Apoptosis was detected with TUNEL, western blot, and flow cytometry. The interaction of METTL3 and neprilysin was determined with RIP-qPCR and MeRIP. KEY FINDINGS: METTL3 expression and apoptosis were increased in alveolar epithelial cells of mice treated with LPS, and METTL3-CKO or METTL3 inhibitor STM2457 could alleviate apoptosis and LPS-induced ALI. In MLE-12 cells, LPS-Induced METTL3 expression and apoptosis. Knockdown of METTL3 alleviated, while overexpression of METTL3 exacerbated LPS-induced apoptosis. LPS treatment reduced neprilysin expression, the intervention of neprilysin expression negatively regulated apoptosis without affecting METTL3 expression, and mitigated the promoting effect of METTL3 on LPS-induced apoptosis. Additionally, METTL3 could bind to the mRNA of neprilysin, and reduce its expression. SIGNIFICANCE: Our findings revealed that inhibition of METTL3 could exert anti-apoptosis and ALI-protective effects via restoring neprilysin expression.

The Circ_35953 induced by the NF-κB mediated the septic AKI via targeting miR-7219-5p/HOOK3 and IGFBP7 axis.

A few studies suggested that CircRNAs were involved in the development of septic AKI. However，the role and regulation mechanism of CircRNA_35953 in septic AKI remains unclear. Here, we found that Circ_35953 was induced by LPS via activation of NF-κB signal in BUMPT cells. Functionally, Circ_35953 mediated the LPS induced the apoptosis in BUMPT cells. Moreover, we demonstrated that Circ_35953 sponged miR-7219-5p to upregulate the expression of HOOK3 and IGFBP7. Finally, we verified that knock down of Circ_35953 alleviated the progression of CLP-induced AKI via targeting the miR-7219-5p/HOOK3 and IGFBP7 signal. Collectively, the data suggested that Circ_35953 /miR-7219-5p/HOOK3 and IGFBP7 axis mediated the septic AKI, which also revealed a potential mechanism of septic AKI.

Low dose Taxol ameliorated renal fibrosis in mice with diabetic kidney disease by downregulation of HIPK2.

Our previous studies reported that low-dose paclitaxel (Taxol) ameliorated renal fibrosis in the unilateral ureteral obstruction and remnant kidney models. However, the regulatory role of Taxol in diabetic kidney disease (DKD) is still unclear. Herein, we observed that low-dose Taxol attenuated high glucose-increased expression of fibronectin, collagen I and collagen IV in Boston University mouse proximal tubule cells. Mechanistically, Taxol suppressed the expression of homeodomain-interacting protein kinase 2 (HIPK2) via disrupting the binding of Smad3 to HIPK2 promoter region, and consequently inhibited the activation of p53. Besides, Taxol ameliorated RF in Streptozotocin mice and db/db-induced DKD via suppression of Smad3/HIPK2 axis as well as inactivation of p53. Altogether, these results suggest that Taxol can block Smad3-HIPK2/p53 axis, thereby attenuating the progression of DKD. Hence, Taxol is a promising therapeutic drug for DKD.

Trends in using of antihypertensive medication among US CKD adults, NHANES 2001-2018.

Objective: Blood pressure (BP) control rates among adult patients taking antihypertensive medications in the United States have not improved over the last decade. Many CKD adults require more than one class of antihypertensive agent to reach the BP target recommended by the guidelines. However, no study has quantified the proportion of adult CKD patients taking antihypertensive medication who are on monotherapy or combination therapy. Methods: National Health and Nutrition Examination Survey data during 2001-2018 was used, including adults with CKD taking antihypertensive medication (age ≥ 20 years, n = 4,453). BP control rates were investigated under the BP targets recommended by the 2021 KDIGO, the 2012 KDIGO, and the 2017 ACC/AHA guidelines. Results: The percentages of uncontrolled BP among US adults with CKD taking antihypertensive medication were 81.4% in 2001-2006 and 78.2% in 2013-2018. The proportion of monotherapy of antihypertensive regimen were 38.6, 33.3, and 34.6% from 2001 to 2006, 2007-2012, and 2013-2018, with no obvious difference. Similarly, there was no significant change in percentages of dual-therapy, triple-therapy, and quadruple-therapy. Although proportion of CKD adults not treated with ACEi/ARB decreased from 43.5% in 2001-2006 to 32.7% in 2013-2018, treatment of ACEi/ARB among patients with ACR > 300 mg/g had no significant change. Conclusion: The BP control rates among US adult CKD patients taking antihypertensive medications have not improved from 2001 to 2018. Mono-therapy accounted for about one third of adult CKD patients taking antihypertensive medication and not changed. Increasing antihypertensive medication combination therapy may help improve BP control in CKD adults in the United States.

Different clinical characteristics of current smokers and former smokers with asthma: a cross-sectional study of adult asthma patients in China.

Smoking is a trigger for asthma, which has led to an increase in asthma incidence in China. In smokers, asthma management starts with smoking cessation. Data on predictors of smoking cessation in Chinese patients with asthma are scarce. The objective of this study was to find the differences in clinical characteristics between current smokers and former smokers with asthma in order to identify factors associated with smoking cessation. Eligible adults with diagnosed asthma and smoking from the hospital outpatient clinics (n = 2312) were enrolled and underwent a clinical evaluation, asthma control test (ACT), and pulmonary function test. Information on demographic and sociological data, lung function, laboratory tests, ACT and asthma control questionnaire (ACQ) scores was recorded. Patients were divided into a current smokers group and a former smokers group based on whether they had quit smoking. Logistic regression analysis was used to analyze the factors associated with smoking cessation. Of all patients with asthma, 34.6% were smokers and 65.4% were former smokers, and the mean age was 54.5 ± 11.5 years. Compared with current smokers, the former smokers were older, had longer duration of asthma, had higher ICS dose, had more partially controlled and uncontrolled asthma, had more pack-years, had smoked for longer, and had worse asthma control. The logistic regression model showed that smoking cessation was positively correlated with age, female sex, pack-years, years of smoking, partially controlled asthma, uncontrolled asthma, and body mass index (BMI), but was negatively correlated with ACT, FEV1, FEV1%predicted, and widowed status. More than 30% of asthma patients in the study were still smoking. Among those who quit smoking, many quit late, often not realizing they need to quit until they have significant breathing difficulties. The related factors of smoking cessation identified in this study indicate that there are still differences between continuing smokers and former smokers, and these factors should be focused on in asthma smoking cessation interventions to improve the prognosis of patients with asthma.

LncRNA 148400 Promotes the Apoptosis of Renal Tubular Epithelial Cells in Ischemic AKI by Targeting the miR-10b-3p/GRK4 Axis.

Although recent studies have reported that long non-coding RNA (lncRNA) is involved in the development of ischemic acute kidney injury (AKI), the exact function and regulatory mechanism of lncRNAs in ischemic AKI remain largely unknown. Herein, we found that ischemic injury promoted the expression of lncRNA 148400 in mouse proximal tubule-derived cell line (BUMPT) and C57BL/6J mice. Furthermore, the lncRNA148400 mediates ischemic injury-induced apoptosis of BUMPT cells. Mechanistically, lncRNA 148400 sponged miR-10b-3p to promote apoptosis via GRK4 upregulation. Finally, knockdown of lncRNA 148400 alleviated the I/R-induced deterioration of renal function, renal tubular injury, and cell apoptosis. In addition, cleaved caspase-3 is increased via targeting the miR-10b-3p/GRK4 axis. Collectively, these results showed that lncRNA 148400/miR-10b-3p/GRK4 axis mediated the development of ischemic AKI.

LncRNA ENSMUST00000171502 Induced by HIF-1α Ameliorates Ischemic Acute Kidney Injury via Targeting the miR-130b-3p/Mybl-1 Axis.

Background: Numerous studies have suggested that long non-coding RNA (lncRNA) affects the progression of ischemic acute kidney injury (IAKI). However, little information is currently available concerning the mechanisms of lncRNA171502 involved in IAKI. Methods: We applied an RT-qPCR assay for the expression of lncRNA171502 and miRNA-130b-3p, immunoblotting for the detection of Mybl-1-myeloblastosis oncogene-like 1 (Mybl-1) and cleaved caspase-3 (CC3) expression, and flow cytometry (FCM) for the evaluation of apoptosis. Result: Initially, lncRNA171502 was induced by HIF-1α in the mouse proximal tubular (BUMPT) cell line and C57BL/6J mice during ischemic injury. Secondly, ischemic injury-induced BUMPT cell apoptosis was markedly relieved following the overexpression of lncRNA171502. However, this effect was enhanced by the knockdown of lncRNA171502. Mechanistically, lncRNA171502 could sponge miRNA-130b-3p and would subsequently upregulate the expression of Mybl-1 to drive the apoptotic process. Lastly, the overexpression of lncRNA171502 alleviated the development of IAKI by targeting miRNA-130b-3p/Mybl-1 pathways. Conclusions: In summary, the HIF-1α/lncRNA171502/miRNA-130b-3p/Mybl-1 axis prevented the progression of IAKI and might serve as a potential therapeutic target.

EGFR mediated the renal cell apoptosis in rhabdomyolysis-induced model via upregulation of autophagy.

AIMS: Rhabdomyolysis is a life-threatening condition. One of the most common complications of rhabdomyolysis is acute kidney injury (AKI), and 10 % of all AKI patients present with rhabdomyolysis. EGFR is associated with different types of AKI. However, the function and regulatory mechanism of EGFR in rhabdomyolysis-induced AKI model remain unknown. Here, we performed the experiments to explore the role of EGFR in this model. MAIN METHODS: We used proximal tubule-specific Atg7 knockout mice and Wa-2 mice to establish animal models. Then, the samples were collected for pathology assay and IB detection. In vitro, the BUMPT cells treated with myoglobin were collected for the detection of apoptosis and autophagy. IB detection were processed for the analysis of protein expressions, FCM analysis for the cell apoptosis, GFP-LC3 transfection and immunofluorescent for autophagy. KEY FINDINGS: EGFR promotes autophagy to mediate rhabdomyolysis-induced AKI via STAT3/Atg7 axis, and gefitinib is a potential therapeutic option for AKI. Here, we demonstrated that EGFR was activated by myoglobin and glycerol both in vitro and in vivo, respectively. Genetic or pharmacological inhibition of EGFR ameliorated myoglobin and glycerol-induced renal cell apoptosis. Mechanistically, EGFR mediated autophagy induction via STAT3/Atg7 axis, thereby resulting in kidney cell apoptosis. Furthermore, Wa-2 mice or gefitinib treatment prevented the progression of rhabdomyolysis-induced AKI as well as renal cell apoptosis and autophagy via inhibiting STAT3/Atg7 axis. SIGNIFICANCE: Researchers can use this finding to better study the function and regulatory mechanism of EGFR in RM-induced AKI model. And gefitinib represents a potential target for treatment of AKI.

MBD2 mediates Th17 cell differentiation by regulating MINK1 in Th17-dominant asthma.

Objectives: .Asthma is a highly heterogeneous disease, and T-helper cell type 17 (Th17) cells play a pathogenic role in the development of non-T2 severe asthma. Misshapen like kinase 1 (MINK1) is involved in the regulation of Th17 cell differentiation, but its effect on severe asthma remains unclear. Our previous studies showed that methyl-CpG binding domain protein 2 (MBD2) expression was significantly increased in patients with Th17 severe asthma and could regulate Th17 cell differentiation. The aim of this study was to investigate how MBD2 interacts with MINK1 to regulate Th17 cell differentiation in Th17-dominant asthma. Materials and methods: Female C57BL/6 mice and bronchial epithelial cells (BECs) were used to establish mouse and cell models of Th17-dominant asthma, respectively. Flow cytometry was used to detect Th17 cell differentiation, and the level of IL-17 was detected by enzyme-linked immunosorbent assay (ELISA). Western blot and quantitative real-time PCR (qRT-PCR) were used to detect MBD2 and MINK1 expression. To investigate the role of MBD2 and MINK1 in Th17 cell differentiation in Th17-dominant asthma, the MBD2 and MINK1 genes were silenced or overexpressed by small interfering RNA and plasmid transfection. Results: Mouse and BEC models of Th17-dominant asthma were established successfully. The main manifestations were increased neutrophils in BALF, airway hyperresponsiveness (AHR), activated Th17 cell differentiation, and high IL-17 levels. The expression of MBD2 in lung tissues and BECs from the Th17-dominant asthma group was significantly increased, while the corresponding expression of MINK1 was significantly impaired. Through overexpression or silencing of MBD2 and MINK1 genes, we have concluded that MBD2 and MINK1 regulate Th17 cell differentiation and IL-17 release. Interestingly, MBD2 was also found to negatively regulate the expression of MINK1. Conclusion: Our findings have revealed new roles for MBD2 and MINK1, and provide new insights into epigenetic regulation of Th17-dominant asthma, which is dominated by neutrophils and Th17 cells. This study could lead to new therapeutic targets for patients with Th17-dominant asthma.

CircRNA_45478 promotes ischemic AKI by targeting the miR-190a-5p/PHLPP1 axis.

A few studies suggested that circular RNAs were involved in the development of ischemic acute kidney injury (AKI). However, the function and regulation mechanism of circRNA_45478 in ischemic AKI remains unknown. In the present study, ischemic injury induced the expressions of circRNA_45478 in mouse proximal tubule-derived cell lines (BUMPT cells) and kidneys of C57BL/6 mice. Functionally, circRNA_45478 mediated I/R-induced apoptosis in BUMPT cells. Mechanistically, circRNA_45478 upregulated the expression of Pleckstrin homology (PH) domain leucine-rich repeat protein phosphatase 1 (PHLPP1) via sponging of microRNA (miR)-190a-5p. Finally, inhibition of circRNA_45478 significantly alleviated the progression of ischemic AKI through regulation of the miR-190a-5p/PHLPP1 pathway. Taken together, our data showed that circRNA_45478/miR-190a-5p/PHLPP1 axis mediated the progression of ischemic AKI.

Androgen Plays a Potential Novel Hormonal Therapeutic Role in Th17 Cells Predominant Neutrophilic Severe Asthma by Attenuating BECs Regulated Th17 Cells Differentiation via MBD2 Expression.

T helper 17 (Th17) cells subtype of non-T2 asthma is less responsive (resistant) to inhaled corticosteroids (ICS), so also called severe asthma. Methyl-CpG-binding domain protein 2 (MBD2) regulates the differentiation of the Th17 cells, showing the possibility of a therapeutic target in severe asthma. Androgen tends to show beneficial therapeutic effects and is a "hot research topic," but its role in the differentiation and expression of Th17 cells via MBD2 is still unknown. The aim of this study was to evaluate how sex hormone interacts with MBD2 and affects the differentiation and expression of Th17 cells in severe asthma. Here, first, we measured the concentration of androgen, estrogen, and androgen estrogen ratio from subjects and correlated it with severe asthma status. Then, we established an animal model and bronchial epithelial cells (BECs) model of severe asthma to evaluate the role of MBD2 in the differentiation and expression of Th17 cells (IL-17), the therapeutic potential of sex hormones in severe asthma, and the effect of sex hormones in BECs regulated Th17 cells differentiation via MBD2 at the cellular level. Increased MBD2 expression and Th17 cells differentiation were noted in the animal and the BECs severe asthma models. Th17 cell differentiation and expression were MBD2 dependent. Androgen attenuated the differentiation of BECs regulated Th17 cells via MBD2 showing BECs as a therapeutic target of androgen, and these findings postulate the novel role of androgen in Th17 cells predominant neutrophilic severe asthma therapy through targeting MBD2.

MiR-6918-5p prevents renal tubular cell apoptosis by targeting MBD2 in ischemia/reperfusion-induced AKI.

AIMS: Although previous studies reported that miRNAs are involved in the progression of acute kidney injury (AKI), their exact function and mechanism in ischemic AKI remains largely unknown. This study aims to define the role of miR-6918-5p in ischemia-reperfusion AKI. Materials and methods The renal arteries of C57BL/6J mice were clamped to establish a model of ischemia-reperfusion renal injury. BUMPT cells were added with Antimycin A and calcium ionophore to establish a model of ATP depletion in vitro. Cell apoptosis was detected by CCK8, flow cytometry and western blot, while HE staining and TUNEL staining were used to assess the degree of kidney damage. KEY FINDINGS: We suppressed mmu_miR-6918-5p by ischemic injury in vitro and in vivo. We found that ischemia-reperfusion (I/R)-induced renal tubular cell apoptosis and the expression of cleaved caspase3 were enhanced by the inhibitor of mmu_miR-6918-5p; this effect was attenuated by an mmu_miR-6918-5p mimic. Mechanistically, mmu_miR-6918-5p binds to the 3' UTR region of MBD2 and represses its expression. The mmu_miR-6918-5p mimic alleviated the ischemic AKI by targeting MBD2. Conversely, the inhibitor of mmu_miR-6918-5p enhanced the ischemic AKI; this was diminished by MBD2-KO. SIGNIFICANCE: Mmu_miR-6918-5p protected against the development of ischemic AKI by targeting MBD2.

mmu-lncRNA 121686/hsa-lncRNA 520657 induced by METTL3 drive the progression of AKI by targeting miR-328-5p/HtrA3 signaling axis.

The pathogenesis of acute kidney injury (AKI) is still not fully understood, and effective interventions are lacking. Here, we explored whether methyltransferase 3 (METTL3) was involved in the progression of AKI via regulation of cell death. We reported that PT（proximal tubule）-METTL3-knockout (KO) noticeably suppressed ischemic-induced AKI via inhibition of renal cell apoptosis. Furthermore, we also found that the expression of mmu-long non-coding RNA (lncRNA) 121686 was upregulated in antimycin-treated Boston University mouse proximal tubule (BUMPT) cells and a mouse ischemia-reperfusion (I/R)-induced AKI model. Functionally, mmu-lncRNA 121686 could promote I/R-induced mouse renal cell apoptosis. Mechanistically, mmu-lncRNA 121686 acted as a competing endogenous RNA (ceRNA) to prevent microRNA miR-328-5p-mediated downregulation of high-temperature requirement factor A 3 (Htra3). PT-mmu-lncRNA 121686-KO mice significantly ameliorated the ischemic-induced AKI via the miR-328-5p/HtrA3 axis. In addition, hsa-lncRNA 520657, homologous with lncRNA 121686, sponged miR-328-5p and upregulated Htra3 to promote I/R-induced human renal cell apoptosis. Interestingly, we found that mmu-lncRNA 121686/hsa-lncRNA 520657 upregulation were dependent on METTL3 via N6-methyladenosine (m6A) modification. The mmu-lncRNA 121686/miR-328-5p or hsa-lncRNA 520657/miR-328-5p /HtrA3 axis was induced in vitro by METTL3 overexpression; in contrast, this effect was attenuated by METTL3 small interfering RNA (siRNA). Furthermore, we found that PT-METTL3-KO or METTL3 siRNA significantly suppressed ischemic, septic, and vancomycin-induced AKI via downregulation of the mmu-lncRNA 121686/miR-328-5p/HtrA3 axis. Taken together, our data indicate that the METTL3/mmu-lncRNA 121686/hsa-lncRNA 520657/miR-328-5p/HtrA3 axis potentially acts as a therapeutic target for AKI.

LncRNA 122049 suppresses apoptosis of renal tubular epithelial cells in ischemic AKI by targeting the miR-330-5p/ELK1 axis.

Several studies have reported that long non-coding RNAs (LncRNAs) were associated with the progression of acute kidney injury (AKI). However, the role and regulation mechanism of lncRNA122049 in ischemic AKI remains unknown. In the present study, we found that lncRNA 122049 protected against the ischemia/reperfusion (I/R) induced apoptosis in BUMPT cells. Mechanistically, the lncRNA 122049 directly sponged miR-330-5p, then increased the expression of ELK1(ETS transcription factor ELK1) to decrease renal cell apoptosis. In addition, miR-330-5p inhibitor completely reversed the pro-apoptotic effect of LncRNA 122049 siRNA on I/R-induced BUMPT cells apoptosis. Finally, overexpression of lncRNA 122049 attenuated ischemic mice AKI via targeting of the miR-330-5p/ELK1 axis. Collectively, the data demonstrated that LncRNA 122049 prevented the I/R-induced renal cell apoptosis via regulation of the miR-330-5p/ELK1 axis, which brings new insights into the pathogenesis and potential targeted treatment of ischemic AKI.

Inhibition of PKC-δ reduce rhabdomyolysis-induced acute kidney injury.

Despite extensive research, the mechanisms underlying rhabdomyolysis-induced acute kidney injury (AKI) remain largely elusive. In this study, we established both cell and murine models of rhabdomyolysis-induced AKI by using myoglobin and glycerin, respectively, and provided evidence that protein kinase Cδ (PKC-δ) was activated in both models and subsequently promoted cell apoptosis. Moreover, we found that this detrimental effect of PKC-δ activation can be reversed by its pharmaceutical inhibitor rottlerin. Furthermore, we detected and confirmed the existence of PKC-δ-mediated myoglobin-induced cell apoptosis and the expression of TNF-α and IL1-ß via regulation of the p38MAPK and ERK1/2 signalling pathways. In summary, our research revealed the role of PKC-δ in renal cell apoptosis and suggests that PKC-δ is a viable therapeutic target for rhabdomyolysis-induced AKI.

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.