Adherence to healthy lifestyle was associated with an attenuation of the risk of chronic kidney disease from metabolic dysfunction-associated fatty liver disease: Results from two prospective cohorts.

AIMS: Non-alcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated fatty liver disease (MAFLD) are important risk factors of chronic kidney disease (CKD). Whether adherence to a healthy lifestyle can modify these effects remain unknown. This study aimed to evaluate the modification effects of healthy lifestyle on the associations among NAFLD, MAFLD, and the risk of CKD, with taking into the effect of genetic risk. METHODS: The Tianjin Chronic Low-grade Systemic Inflammation and Health Cohort Study (TCLSIH), the UK Biobank Study (UKB). The outcome was incident CKD. The exposures including NAFLD, MAFLD, healthy lifestyle, and a genetic risk score (GRS) for CKD. RESULTS: After 1,135,334 person-year follow-up, we documented 2975 incident CKD cases in the two cohorts. MAFLD and NAFLD were associated with a higher risk of CKD, particularly in patients with MAFLD. In the TCLSIH and UKB, the hazard ratios (95% confidence intervals) of incident CKD for MAFLD were 1.47 (1.30, 1.66) and 1.73 (1.57, 1.91), respectively. Adherence to a healthier lifestyle decreased the risk of CKD from MAFLD with significant interaction effects (TCLSIH: Pinteraction = 0.02; UKB: Pinteraction = 0.04). Participants with a lower CKD-GRS experienced a higher risk of CKD from MAFLD, but achieved two healthy lifestyles can significantly decreased the risk of CKD in patients with MAFLD. CONCLUSIONS: MAFLD and NAFLD are associated with a higher CKD risk, particularly MAFLD. Adherence to a healthier lifestyle was associated with a lower risk of CKD from MAFLD. These results highlight the important role of following a healthy lifestyle to prevent CKD.

Nrf2 protects against renal fibrosis induced by chronic cadmium exposure in mice.

Environmental cadmium (Cd) exposure is a serious public health concern, as the kidney is the primary target for Cd exposure. The present study aimed to investigate the role and underlying mechanisms of nuclear factor erythroid-derived 2-like 2 (Nrf2) in renal fibrosis induced by chronic Cd exposure. Nrf2 knockout (Nrf2-KO) mice and their wild-type littermates (Nrf2-WT) were exposed to 100 or 200 ppm Cd in drinking water for up to 16 or 24 weeks. Following the Cd exposures, Nrf2-KO mice showed elevated urinary neutrophil gelatinase-associated lipocalin (NGAL) and BUN levels compared to Nrf2-WT mice. Masson's trichrome staining and expression of fibrosis-associated proteins revealed that more severe renal fibrosis occurred in Nrf2-KO than that in Nrf2-WT mice. Renal Cd content in the Nrf2-KO mice exposed to 200 ppm Cd was lower than that in Nrf2-WT mice, which might be a consequence of the severe renal fibrosis in the Nrf2-KO mice. Mechanistic studies showed that Nrf2-KO mice exhibited higher levels of oxidative damage, lower antioxidant levels, and more regulated cell death, apoptosis in particular, than those in Nrf2-WT mice caused by Cd exposure. In conclusion, Nrf2-KO mice were more prone to develop renal fibrosis induced by chronic Cd exposure, partially due to a weakened antioxidant, detoxification capacity and increased oxidative damage.

N6-methyladenine RNA Methylation Epigenetic Modification and Kidney Diseases.

RNA methylation modification is a rapidly developing field in epigenetics. N6-methyladensine (m6A) is the most common internal modification in eukaryotic mRNA. m6A group regulates RNA splicing, stability, translocation, and translation. Enzymes catalyzing this process were termed as writers, erasers, and readers. Recent studies have focused on exploring the role of RNA methylation in human diseases. RNA methylation modifications, particularly m6A, play important roles in the pathogenesis of kidney diseases. In this review, we provide a brief description of m6A and summarize the impact of m6A on acute and chronic kidney disease (CKD) and possible future study directions for this research.

IL-18 deficiency ameliorates the progression from AKI to CKD.

Inflammation is an important factor in the progression from acute kidney injury (AKI) to chronic kidney disease (CKD). The role of interleukin (IL)-18 in this progression has not been examined. We aimed to clarify whether and how IL-18 limits this progression. In a folic acid induced renal injury mouse model, we studied the time course of kidney injury and renal IL-18 expression. In wild-type mice following injection, renal IL-18 expression increased. In parallel, we characterized other processes, including at day 2, renal tubular necroptosis assessed by receptor-interacting serine/threonine-protein kinase1 (RIPK1) and RIPK3; at day 14, transdifferentiation (assessed by transforming growth factor ß1, vimentin and E-cadherin); and at day 30, fibrosis (assessed by collagen 1). In IL-18 knockout mice given folate, compared to wild-type mice, tubular damage and necroptosis, transdifferentiation, and renal fibrosis were attenuated. Importantly, IL-18 deletion decreased numbers of renal M1 macrophages and M1 macrophage cytokine levels at day 14, and reduced M2 macrophages numbers and macrophage cytokine expression at day 30. In HK-2 cells, IL-18 knockdown attenuated necroptosis, transdifferentiating and fibrosis.In patients with tubulointerstitial nephritis, IL-18 protein expression was increased on renal biopsies using immunohistochemistry. We conclude that genetic IL-18 deficiency ameliorates renal tubular damage, necroptosis, cell transdifferentiation, and fibrosis. The renoprotective role of IL-18 deletion in the progression from AKI to fibrosis may be mediated by reducing a switch in predominance from M1 to profibrotic M2 macrophages during the process of kidney repair.

circMTND5 Participates in Renal Mitochondrial Injury and Fibrosis by Sponging MIR6812 in Lupus Nephritis.

Recent studies have focused on nuclear-encoded circular RNAs (circRNAs) in kidney diseases, but little is known about mitochondrial circRNAs. Differentially expressed circRNAs were analyzed by RNA deep sequencing from lupus nephritis (LN) biopsies and normal human kidneys. In LN renal biopsies, the most downregulated circRNA was circMTND5, which is encoded in the mitochondrial genome. We quantitated circMTND5 by qPCR and localized by fluorescence in situ hybridization (FISH). Mitochondrial abnormalities were identified by electron microscopy. The expression of mitochondrial genes was decreased, and the expression of profibrotic genes was increased on qPCR and immunostaining. RNA binding sites for MIR6812 and circMTND5 were predicted. MIR6812 expression was increased by FISH and qPCR. In HK-2 cells and its mitochondrial fraction, the role of circMTND5 sponging MIR6812 was assessed by their colocalization in mitochondria on FISH, RNA immunoprecipitation, and RNA pulldown coupled with luciferase reporter assay. circMTND5 knockdown upregulated MIR6812, decreased mitochondrial functional gene expression, and increased profibrotic gene expression. Overexpression of circMTND5 reversed these effects in hTGF-ß stimulated HK-2 cells. Similar effects were observed in HK-2 cells with overexpression and with knockdown of MIR6812. We conclude that circMTND5 alleviates renal mitochondrial injury and kidney fibrosis by sponging MIR6812 in LN.

LNA-anti-miR-150 alleviates renal interstitial fibrosis by reducing pro-inflammatory M1/M2 macrophage polarization.

Renal interstitial fibrosis (RIF) is a common pathological feature contributing to chronic injury and maladaptive repair following acute kidney injury. Currently, there is no effective therapy for RIF. We have reported that locked nuclear acid (LNA)-anti-miR-150 antagonizes pro-fibrotic pathways in human renal tubular cells by regulating the suppressor of cytokine signal 1 (SOCS1)/Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. In the present study, we aimed to clarify whether LNA-anti-miR-150 attenuates folic acid-induced RIF mice by regulating this pathway and by reducing pro-inflammatory M1/M2 macrophage polarization. We found that renal miR-150 was upregulated in folic acid-induced RIF mice at day 30 after injection. LNA-anti-miR-150 alleviated the degree of RIF, as shown by periodic acid-Schiff and Masson staining and by the expression of pro-fibrotic proteins, including alpha-smooth muscle actin and fibronectin. In RIF mice, SOCS1 was downregulated, and p-JAK1 and p-STAT1 were upregulated. LNA-anti-miR-150 reversed the changes in renal SOCS1, p-JAK1, and p-STAT1 expression. In addition, renal infiltration of total macrophages, pro-inflammatory M1 and M2 macrophages as well as their secreted cytokines were increased in RIF mice compared to control mice. Importantly, in folic acid-induced RIF mice, LNA-anti-miR-150 attenuated the renal infiltration of total macrophages and pro-inflammatory subsets, including M1 macrophages expressing CD11c and M2 macrophages expressing CD206. We conclude that the anti-renal fibrotic role of LNA-anti-miR-150 in folic acid-induced RIF mice may be mediated by reducing pro-inflammatory M1 and M2 macrophage polarization via the SOCS1/JAK1/STAT1 pathway.

Emerging Role of Circular RNAs in Kidney Diseases in Nephrology.

BACKGROUND: Circular RNAs (circRNAs) have been identified to be involved in a variety of human diseases such as cancers, cardiovascular diseases, and autoimmune diseases. In recent years, the role of circRNAs in the development of kidney diseases in nephrology has been gradually recognized. OBJECTIVE: We updated and described the current status of circRNAs in kidney diseases in nephrology. We particularly focused on the roles and mechanisms of circRNAs in systemic lupus erythematosus and lupus nephritis. METHODS: We summarized recent reports published on PubMed, Web of Science, Scopus, Scielo databases using keywords circRNAs, kidney diseases or renal diseases, or systemic lupus erythematosus. RESULTS: Studies of circRNAs in certain kidney diseases, such as acute kidney injury, focal segmental glomerulosclerosis, idiopathic membranous nephropathy, IgA nephropathy, diabetic nephropathy, hypertensive renal damage, and particular lupus nephritis address the function and pathogenesis of circRNAs. Mechanisms of circRNAs in the above human kidney diseases so far have focused on the role of sponging microRNAs and regulating the expression of target genes. Moreover, circRNAs have been detected in blood, urine, and kidney tissue samples. These results suggest that circRNAs can serve as biomarkers for the diagnosis and monitoring of the progression of kidney diseases. CONCLUSION: CircRNAs play important roles in the pathogenesis, diagnosis, and treatment of kidney diseases emphasizing lupus nephritis in nephrology.

Co-occurrence of IgA nephropathy and IgG4-Tubulointersitial nephritis effectively treated with tacrolimus: a case report.

BACKGROUND: Cases of concurrent immunoglobulin A nephropathy (IgAN) and IgG4-related tubulointerstitial nephritis (IgG4-TIN) are rare and previous case reports have lacked important data. KDIGO suggests a treatment with systemic glucocorticoids in IgAN patients. Glucocorticoids are recommended as the first-line therapy for IgG4-TIN. The use of tacrolimus as a long-term maintenance treatment has not been described. We report the case of a man who developed IgAN and IgG4-TIN without abnormalities in extra-renal tissue, without renal function abnormalities or impairment as well, and was treated by tacrolimus as a long-term maintenance during 45 months follow-up. CASE PRESENTATION: A 56-year-old Chinese man first presented to our hospital with the chief complaint of foamy urine for 1 year and hematuria for 3 months, with a medical history of hypertension. Testing revealed a notable increase in serum IgG4 level without abnormalities in renal function or imaging, or in dysfunction other organs. Renal biopsy showed mesangial extracellular matrix proliferation, increased mesangial cell numbers and infiltration of plasma cells. Immunofluorescence showed mesangial positivity for IgA and C3. Immunohistochemistry staining showed widespread IgG4 and increased CD38 and CD138 expression. Electron microscopy showed immune complexes located on the tubular basement membrane. He was diagnosed with IgAN and IgG4-TIN. He received glucocorticoids, leflunomide and tacrolimus to induce remission. He was given tacrolimus as long-term maintenance treatment. When tacrolimus was temporarily withdrawn, proteinuria recurred. After resuming tacrolimus therapy, he again entered complete remission. After 45 months of therapy, he remains in complete remission and the serum IgG4 level is normal. CONCLUSIONS: The finding of concurrent IgAN and IgG4-TIN without abnormalities in renal function, imaging or extra-renal tissue is rare and their coexistence may be coincidental. Long-term treatment with tacrolimus proved effective and he has remained in remission during 45 months follow-up.

Nrf2 deficiency aggravates the kidney injury induced by subacute cadmium exposure in mice.

Cadmium (Cd) is a heavy metal pollutant that adversely effects the kidney. Oxidative stress and inflammation are likely major mechanisms of Cd-induced kidney injury. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is crucial in regulating antioxidant and inflammatory responses. To investigate the role of Nrf2 in the development of subacute Cd-induced renal injury, we utilized Nrf2 knockout (Nrf2-KO) and control mice (Nrf2-WT) which were given cadmium chloride (CdCl2, 1 or 2 mg/kg i.p.) once daily for 7 days. While subacute CdCl2 exposure induced kidney injury in a dose-dependent manner, after the higher Cd dosage exposure, Nrf2-KO mice showed elevated blood urea nitrogen (BUN) and urinary neutrophil gelatinase-associated lipocalin (NGAL) levels compared to control. In line with the findings, the renal tubule injury caused by 2 mg Cd/kg, but not lower dosage, in Nrf2-KO mice determined by Periodic acid-Schiff staining was more serious than that in control mice. Further mechanistic studies showed that Nrf2-KO mice had more apoptotic cells and severe oxidative stress and inflammation in the renal tubules in response to Cd exposures. Although there were no significant differences in Cd contents of tissues between Cd-exposed Nrf2-WT and Nrf2-KO mice, the mRNA expression of Nrf2 downstream genes, including heme oxygenase 1 and metallothionein 1, were significantly less induced by Cd exposures in the kidney of Nrf2-KO compared with Nrf2-WT mice. In conclusion, Nrf2-deficient mice are more sensitive to kidney injury induced by subacute Cd exposure due to a muted antioxidant response, as well as a likely diminished production of specific Cd detoxification metallothioneins.

circHIPK3 Exacerbates Folic Acid-Induced Renal Tubulointerstitial Fibrosis by Sponging miR-30a.

Renal tubulointerstitial fibrosis is a common pathological feature of progressive chronic kidney disease (CKD), and current treatment has limited efficacy. The circular RNA circHIPK3 is reported to participate in the pathogenesis of various human diseases. However, the role of circHIPK3 in renal fibrosis has not been examined. In this study, we aimed to determine whether and how circHIPK3 might participate in the pathogenesis of renal fibrosis. Mice received a peritoneal injection of folic acid (250 mg/kg). Of note, 30 days later, renal fibrosis was present on periodic acid-Schiff (PAS) and Masson staining, and mRNA and protein of profibrotic genes encoding fibronectin (FN) and collagen 1 (COL1) were increased. Renal circHIPK3 was upregulated, while miR-30a was downregulated, assessed by quantitative PCR (qPCR) and fluorescence in situ hybridization (FISH). The expression of transforming growth factor beta-1 (TGF-ß1) was increased by qPCR analysis, immunoblotting, and immunofluorescence. Renal circHIPK3 negatively correlated with miR-30a, and kidney miR-30a negatively correlated with TGF-ß1. Target Scan and miRanda algorithms predicted three perfect binding sites between circHIPK3 and miR-30a. We found that circHIPK3, miR-30a, and TGF-ß1 colocalized in the cytoplasm of human tubular epithelial cells (HK-2 cells) on FISH and immunofluorescence staining. We transfected circHIPK3 and a scrambled RNA into HK-2 cells; miR-30a was downregulated, and the profibrotic genes such as TGF-ß1, FN, and COL1 were upregulated and assessed by qPCR, immunoblotting, and immunofluorescence staining. Third, the upregulation of circHIPK3, downregulation of miR-30a, and overproduction of profibrotic FN and COL1 were also observed in HK-2 cells exposed to TGF-ß1. Finally, renal biopsies from patients with chronic tubulointerstitial nephritis manifested similar expression patterns of circHIPK3, miR-30a, and profibrotic proteins, such as TGF-ß1, FN, and COL1 as observed in the experimental model. A feed-forward cycle was observed among circHIPK3, miR-30a, and TGF-ß1. Our results suggest that circHIPK3 may contribute to progressive renal fibrosis by sponging miR-30a. circHIPK3 may be a novel therapeutic target for slowing CKD progression.

miR-150-Based RNA Interference Attenuates Tubulointerstitial Fibrosis through the SOCS1/JAK/STAT Pathway In Vivo and In Vitro.

We investigated whether microRNA-150 (miR-150)-based RNA interference (RNAi) ameliorates tubular injury and tubulointerstitial fibrosis. Mice injected with folic acid developed tubulointerstitial fibrosis at day 30. miR-150 levels were increased at day 7 and peaked at day 30. At day 30, protein levels of α-smooth muscle actin, fibronectin (FN), and collagen 1 (COL-1) were increased, while suppressor of cytokine signal 1 (SOCS1) was decreased. Kidneys manifested increased macrophage numbers and increased expression of potential mediators: interferon-γ, interleukin-6, and tumor necrosis factor-α. Locked nucleic acid-anti-miR-150, started prior to or after tubular injury and administered twice weekly for 4 weeks, reversed renal inflammation and fibrosis. In HK-2 cells, co-culture with macrophages increased miR-150 expression and decreased SOCS1. Janus kinase (JAK) and signal transducer and activators of transcription (STAT) pathway-related proteins p-JAK1, p-JAK2, p-STAT1, p-STAT3, and pro-fibrotic genes encoding α-smooth muscle actin, FN, and COL-1 were all upregulated. The miR-150 antagonist reversed these transcriptional changes. Lastly, in renal biopsies from patients with chronic interstitial fibrosis, renal miR-150, and pro-fibrotic gene expression and macrophage numbers were increased, while SOCS1 expression was decreased. In conclusion, miR-150-based RNAi is as a potential novel therapeutic agent for tubulointerstitial fibrosis, suppressing the SOCS1/JAK/STAT pathway and reducing macrophage influx.

CircZNF609 is involved in the pathogenesis of focal segmental glomerulosclerosis by sponging miR-615-5p.

As a set of distinct syndromes, focal segmental glomerulosclerosis (FSGS) is the most common cause of adult nephrotic syndrome with diverse mechanisms. We recently found that expression of the circular RNA circZNF609 is increased in renal biopsies of lupus nephritis patients. In the present study, we aimed to determine whether circZNF609 participates in the pathogenesis of FSGS in mice given Adriamycin. In FSGS mice, circZNF609 was upregulated while miR-615-5p was downregulated in FSGS mice analyzed by qPCR and fluorescence in situ hybridization (FISH). Expression of podocyte proteins Wilms tumor 1 (WT1) and podocin were decreased, while expression of collagen 1 (COL1) and transforming growth factor-beta1 (TGF-ß1) were increased on Western blotting. Renal circZNF609 levels were positively correlated and miR-615-5p levels were negatively correlated with the degree of podocyte injury and renal fibrosis. Importantly, circZNF609 and miR-615-5p co-localized to glomeruli and tubules on FISH. Perfect match seeds were found between circZNF609 and miR-615-5p and COL1 mRNA, leading us to explore mechanisms of circZNF609 in bovine serum albumin (BSA) stimulating HK-2 cells, which model the toxicity of proteinuria on tubular cells. In vitro studies, circZNF609 increased and miR-615-5p decreased after BSA treatment and were negatively correlated with each other. COL1 and TGF-ß1 were both upregulated and negatively correlated with miR-615-5p. Lastly, circZNF609 expression increased in glomeruli and tubules of FSGS patient renal biopsies. We conclude that circZNF609 may play an important role in FSGS by sponging miR-615-5p.

miR-150 inhibitor ameliorates adriamycin-induced focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is the most common cause of adult nephrotic syndrome in USA. Its mechanisms remain unclear and the effective treatment lacks. We previously reported that upregulation of microRNA (miR)-150 in human podocytes increases profibrotic proteins and decreases anti-fibrotic suppressor of cytokine signaling 1 (SOCS1). We aimed to clarify whether miR-150 inhibitor can ameliorate glomerular injury and to identify its corresponding mechanisms in adriamycin-induced FSGS mice. We found that renal miR-150 increased in adriamycin-induced FSGS mice and FAM-labeled locked nucleic acid-anti-miR-150 (LNA-anti-miR-150) was absorbed by the animal kidneys 6 h after subcutaneous injection. The administration of LNA-anti-miR-150 (2 mg/kg BW twice weekly for 6 w) inhibited renal miR-150 levels without systemic toxicity. With renal miR-150 inhibition, proteinuria, hypoalbuminemia, and hyperlipemia were ameliorated in FSGS mice compared to the scrambled LNA. Meanwhile, the elevated profibrotic proteins and proinflammatory cytokines, decreased antifibrotic SOCS1, and the filtration of T cells in FSGS mice were reverted by LNA-anti-miR-150. Finally, we found that miR-150 most located on podocytes in renal biopsies of FSGS patients. We conclude that LNA-anti-miR-150 might be a novel promising therapeutic agent for FSGS. The renal protective mechanisms might be mediated by anti-fibrosis and anti-inflammation as well as reducing infiltration of T cells in the kidney.

LNA-anti-miR-150 ameliorated kidney injury of lupus nephritis by inhibiting renal fibrosis and macrophage infiltration.

BACKGROUND: The prevalence of lupus nephritis (LN) remains high despite various emerging monoclonal antibodies against with targeting systemic lupus erythematosus (SLE). Renal fibrosis is the main feature of late stage LN, and novel therapeutic agents are still needed. We previously reported that microRNA (miR)-150 increases in renal biopsies of American LN patients and that miR-150 agonist promotes fibrosis in cultured kidney cells. Presently, we aim to verify whether locked nucleic acid (LNA)-anti-miR-150 can ameliorate LN in mice and to investigate its corresponding mechanisms. METHODS: We first observed natural history and renal miR-150 expression in female Fcgr2b-/- mice of a spontaneously developed LN model. We then verified miR-150 renal absorption and determined the dose of the suppressed miR-150 by subcutaneous injection of LNA-anti-miR-150 (2 and 4 mg/kg). Thirdly, we investigated the therapeutic effects of LNA-anti-miR-150 (2 mg/kg for 8 weeks) on LN mice and the corresponding mechanisms by studying fibrosis-related genes, cytokines, and kidney resident macrophages. Lastly, we detected the expression of renal miR-150 and the mechanism-associated factors in renal biopsies from new onset untreated LN patients. RESULTS: Fcgr2b-/- mice developed SLE indicated by positive serum autoantibodies at age 19 weeks and LN demonstrated by proteinuria at age 32 weeks. Renal miR-150 was overexpressed in LN mice compared to wild type mice. FAM-labeled LNA-anti-miR-150 was absorbed by both glomeruli and renal tubules. LNA-anti-miR-150 suppressed the elevated renal miR-150 levels in LN mice compared to the scrambled LNA without systemic toxicity. Meanwhile, serum double strand-DNA antibody, proteinuria, and kidney injury were ameliorated. Importantly, the elevated renal pro-fibrotic genes (transforming growth factor-ß1, α-smooth muscle antibody, and fibronectin) and decreased anti-fibrotic gene suppressor of cytokine signal 1 were both reversed. Renal pro-inflammatory cytokines (interferon-γ, interleukin-6, and tumor necrosis factor-α) and macrophages were also decreased. In addition, the changes of renal miR-150 and associated proteins shown in LN mice were also seen in human subjects. CONCLUSIONS: LNA-anti-miR-150 may be a promising novel therapeutic agent for LN in addition to the current emerging monoclonal antibodies, and its renal protective mechanism may be mediated by anti-fibrosis and anti-inflammation as well as reduction of the infiltrated kidney resident macrophages.

Co-occurrence of PLA2R-positive membranous nephropathy without crescents, and PR3-positive eosinophilic granulomatosis with polyangiitis
.

Primary membranous nephropathy (PMN) is a common cause of adult nephrotic syndrome, most commonly associated with autoantibodies against M-type phospholipase A2 receptor (PLA2R). Eosinophilic granulomatosis with polyangiitis (EGPA), previously known as Churg-Strauss syndrome, is a rare disorder characterized by asthma, eosinophilia, and multiorgan vasculitis. Here, we report the case of an adult who presented with typical nephrotic syndrome. Renal biopsy revealed PLA2R-positive PMN without crescents. He had a history of asthma, eczema, and eosinophilia, and testing revealed positive serological proteinase 3 (PR3) and antineutrophil cytoplasmic antibody (ANCA). Further skin and bone marrow biopsy revealed histologic eosinophilic infiltration, and a diagnosis of EGPA was made. The renal biopsy revealed a few eosinophils in glomerular capillary lumen and tubulointerstitial. Treatment with a glucocorticoid and cyclophosphamide was initiated. At 32 months after completing therapy, the patient was in complete clinical remission, and the PR3-ANCA result was negative.

circHLA-C Plays an Important Role in Lupus Nephritis by Sponging miR-150.

Circular RNAs (circRNAs) participate in the pathogenesis of various diseases by sponging microRNAs (miRs). However, the roles of circRNAs remain unreported in glomerular diseases. We previously reported that miR-150 positively correlated with renal chronicity index in patients with lupus nephritis (LN). We aimed to investigate renal circRNA profiling and the interaction between circRNAs and miR-150 in LN patients. Six renal biopsies from untreated female patients with LN class IV and five normal kidney tissues from urology patients were used for circRNA sequencing. 171 circRNAs with 2-fold differential expression were identified in LN compared with normal control. Ten selected circRNAs were validated by real-time qPCR, and seven circRNAs showed the same significant increases as the sequencing results. circHLA-C positively correlated with proteinuria (R = 0.92, p < 0.01), serum creatinine (R = 0.76, p = 0.08), renal activity index (R = 0.88, p < 0.05), and crescentic glomeruli (R = 0.93, p < 0.01). Renal circHLA-C increased 2.72-fold, and miR-150 decreased 66% in LN compared with normal control (p < 0.05). Bio-informatic analysis predicted miR-150 was regulated by circHLA-C and displayed one perfect match seed between circHLA-C and miR-150. The renal miR-150 showed a tendency of negative correlation with circHLA-C in LN patients. In conclusion, circHLA-C may play an important role in the pathogenesis of lupus nephritis by sponging miR-150.

Nrf2 deficiency promotes the progression from acute tubular damage to chronic renal fibrosis following unilateral ureteral obstruction.

Background: Nuclear factor erythroid 2-related factor 2 (Nrf2) is a central mediator of cellular responses to oxidative stress. We hypothesized that Nrf2 modulates progression from acute tubular damage to renal fibrosis. We asked whether Nrf2 deletion increases renal injury in mice following unilateral ureteral obstruction (UUO). Methods: We explored the time course of renal injury and Nrf2 expression in Nrf2+/+ mice following UUO. We compared Nrf2+/+ and Nrf2-/- mice following UUO in tubular damage, transdifferentiation [vimentin, proliferating cell nuclear antigen (PCNA)], fibrosis [fibronectin, α-smooth muscle actin (SMA)], antioxidative and inflammatory responses. We studied Nrf2 in renal biopsies of patients with acute, subacute and chronic tubulointerstitial nephritis (TIN). Results: In Nrf2+/+ mice, renal Nrf2 expression and Nrf2-regulated glutamate-cysteine ligase catalytic (Gclc) and heme oxygenase-1 (Ho-1) were elevated, and renal injury occurred between 2 and 14 days after UUO. On Day 2 following UUO, in Nrf2-/- mice compared with Nrf2+/+ mice, tubular damage, apoptotic cell numbers, cleaved caspase3 and cleaved-poly ADP-ribose polymerase were increased. On Day 5, protein levels of vimentin and PCNA and the co-expressed cells of both proteins were increased. On Day 14, fibronectin and α-SMA protein levels were increased. Nrf2 deletion decreased expression of antioxidative genes (Gclc and Ho-1) and increased expression of inflammatory response genes (Tgfß, Tnf, IL-6, IL-1ß and F4/80). Finally, Nrf2 expression was upregulated in renal biopsies of patients with TIN. Conclusions: Following UUO, Nrf2 deficiency increased tubular damage, transdifferentiation, fibrosis and inflammatory response while decreasing antioxidative responses. The renal protective role of Nrf2 in the development of tubulointerstitial fibrosis in UUO may be mediated by antioxidative and anti-inflammatory pathways.

Pathogenesis of antimicrobial peptides LL-37 and CpG-ODN in ANCA associated vasculitis.

OBJECTIVES: Anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) are a group of systemic autoimmune disorders characterized by necrotizing inflammation of small- to medium-sized blood vessels. The pathogenesis of patients with AAV are still in investigation. In this study, we explored the involvement of LL-37 and nucleic acids in AAV. METHODS: 15 patients with AAV diagnosed according to the Chapel Hill definition between October 2014 and July 2015 in the department of Nephrology of Huangdao, affiliated Hospital of Qingdao University were enrolled. 16 patients with chronic bronchitis (CB) were selected  as disease control group. 15 cases of healthy people from Medical Healthy Center were as healthy control group. Peripheral blood mononuclear cells (PBMCs) were collected from these groups and stimulated by LL-37and (or) two types of CpG-ODN for 7 days. The IFN-α and ANCA in vitro were measured by ELISA. The serum IFN-α, LL-37 and ANCA were measured also. RESULTS: The serum level of IFN-α in AAV group was much higher than that in CB group (692.13 ± 407.28 vs 397.07 ± 211.62 pg/ml, p = 0.019), and that in healthy control group (692.13 ± 407.28 vs 251.54 ± 190.46 pg/ml, p < 0.001). The serum level of LL-37 in AAV group was much higher than that in CB group (101.18 ± 66.59 vs 40.23 ± 13.51 ng/ml, p < 0.001, and that in healthy control group (101.18 ± 66.59 vs 27.80 ± 16.86 ng/ml, p < 0.001). Also the level of IFN-α showed a significant positive relationship with ANCA in AAV group both in serum and in supernatant of cultured PBMCs stimulated by LL-37 and (or) CpG-ODN (r = 0.783, p = 0.001; r = 0.575, p = 0.064; r = 0.649, p = 0.031; r = 0.806, p = 0.003). In patients with AAV, the supernatant levels of IFN-α in cultured PBMCs stimulated by LL-37 and (or) CpG-ODN were higher than that without stimulating factor (p < 0.05). The supernatant level of IFN-α in cultured PBMC stimulated by LL-37 alone was lower than that stimulated by CpGA alone (699.57 ± 476.26 vs 2342.63 ± 2025.11 pg/ml, p = 0.001). But the supernatant level of IFN-α in cultured PBMCs stimulated by LL-37 alone was higher than in that stimulated by CpGB alone (699.57 ± 476.26 vs 153.35 ± 78.08 pg/ml, p < 0.001). The supernatant level of IFN-α in cultured PBMCs stimulated by both LL-37 and CpG-ODN was higher than that stimulated by LL-37 or CpG-ODN alone (2550.57 ± 2217.41 vs 699.57 ± 476.26 pg/ml, p = 0.003; 2550.57 ± 2217.41 vs 153.35 ± 78.08 pg/ml, p = 0.001; 2660.95 ± 391.31 vs 699.57 ± 476.26 pg/ml, p < 0.001; 2660.95 ± 391.31 vs 153.35 ± 78.08 pg/ml, p < 0.001). Either it is stimulated by LL-37 or CpG-ODN or both, the supernatant level of IFN-α in cultured PBMCs in AAV patients was the highest, that in healthy controls was the lowest. Either stimulated by LL-37 or CPG-ODN, or both, the levels of ANCA production in vitro in AAV groups were statistically significantly higher than those in CB group and healthy control group. CONCLUSIONS: There were higher serum levels of LL-37 and IFN-α in patients with AAV. IFN-α could reach a higher level stimulated by LL-37 and nucleic acids both of which are related to infection. Patients with AAV have ANCA-producing B lymphocytes in the circulation even in remission stage. Infections could induce the relapse of AAV.