Selenium nanoparticles alleviate renal ischemia/reperfusion injury by inhibiting ferritinophagy via the XBP1/NCOA4 pathway.

Acute kidney injury (AKI) is closely related to lysosomal dysfunction and ferroptosis in renal tubular epithelial cells (TECs), for which effective treatments are urgently needed. Although selenium nanoparticles (SeNPs) have emerged as promising candidates for AKI therapy, their underlying mechanisms have not been fully elucidated. Here, we investigated the effect of SeNPs on hypoxia/reoxygenation (H/R)-induced ferroptosis and lysosomal dysfunction in TECs in vitro and evaluated their efficacy in a murine model of ischemia/reperfusion (I/R)-AKI. We observed that H/R-induced ferroptosis was accompanied by lysosomal Fe2+ accumulation and dysfunction in TECs, which was ameliorated by SeNPs administration. Furthermore, SeNPs protected C57BL/6 mice against I/R-induced inflammation and ferroptosis. Mechanistically, we found that lysosomal Fe2+ accumulation and ferroptosis were associated with the excessive activation of NCOA4-mediated ferritinophagy, a process mitigated by SeNPs through the upregulation of X-box binding protein 1 (XBP1). Downregulation of XBP1 promoted ferritinophagy and partially counteracted the protective effects of SeNPs on ferroptosis inhibition in TECs. Overall, our findings revealed a novel role for SeNPs in modulating ferritinophagy, thereby improving lysosomal function and attenuating ferroptosis of TECs in I/R-AKI. These results provide evidence for the potential application of SeNPs as therapeutic agents for the prevention and treatment of AKI.

Association between dialysis effluent leukocyte count after initial antibiotic treatment and outcomes of patients with peritoneal dialysis-associated peritonitis: a retrospective study.

BACKGROUND: Among patients with peritoneal dialysis-associated peritonitis (PDAP), It has been regarded as an indicator of deterioration of clinical condition that peritoneal dialysis effluent leukocyte count (PDELC) cannot be restored to normal after initial antibiotic therapy. However, the precise relationship between PDELC on day 5 and the clinical outcomes of PDAP episodes remains uncertain. AIMS: To explore the association between PDELC on day 5 and clinical outcomes of PDAP episodes. METHODS: This retrospective study was based on the medical chart database of the Affiliated Hospital of Guangdong Medical University. Multivariable regressions were used to evaluate the association between PDELC on day 5 and 60-day mortality, half-year mortality, treatment failure, and the length of stay in hospital with adjustment for confounding factors. RESULTS: A total of 549 PDAP episodes in 309 patients were enrolled. The total 60-day mortality, half-year mortality, and rate of treatment failure was 6.0%, 9.8%, and 14.2%, respectively. Compared with patients with normal PDELC, those with PDELC ≥2000 × 106/L on day 5 had significantly higher 60-day mortality (31.1% vs 2.7%), half-year mortality (35.6% vs 5.6%), and treatment failure (46.7% vs 5.7%). In multivariate adjusted regression, the ORs (95%CI) were 6.99 (2.33, 20.92; p = 0.001), 4.97(1.93, 12.77; p = 0.001), and 5.77 (2.07, 16.11; p = 0.001), respectively. Patients with PDELC were 100-2000 × 106/L on day 5 had a higher rate of treatment failure than those with normal PDELC (26.9% vs 5.7%) (OR = 3.03, 95%CI 1.42, 6.46; p = 0.004). After sensitivity analysis, the results remained robust. CONCLUSIONS: Among patients with PDAP, increased PDELC on day 5 was associated with a greater risk of 60-day mortality, half-year mortality, and treatment failure.

Effect of Lacking ZKSCAN3 on Autophagy, Lysosomal Biogenesis and Senescence.

Transcription factors can affect autophagy activity by promoting or inhibiting the expression of autophagic and lysosomal genes. As a member of the zinc finger family DNA-binding proteins, ZKSCAN3 has been reported to function as a transcriptional repressor of autophagy, silencing of which can induce autophagy and promote lysosomal biogenesis in cancer cells. However, studies in Zkscan3 knockout mice showed that the deficiency of ZKSCAN3 did not induce autophagy or increase lysosomal biogenesis. In order to further explore the role of ZKSCAN3 in the transcriptional regulation of autophagic genes in human cancer and non-cancer cells, we generated ZKSCAN3 knockout HK-2 (non-cancer) and Hela (cancer) cells via the CRISPR/Cas9 system and analyzed the differences in gene expression between ZKSCAN3 deleted cells and non-deleted cells through fluorescence quantitative PCR, western blot and transcriptome sequencing, with special attention to the differences in expression of autophagic and lysosomal genes. We found that ZKSCAN3 may be a cancer-related gene involved in cancer progression, but not an essential transcriptional repressor of autophagic or lysosomal genes, as the lacking of ZKSCAN3 cannot significantly promote the expression of autophagic and lysosomal genes.

Efficacy and safety of sequential immunosuppressive treatment for severe IgA nephropathy: A retrospective study.

Background: This study compared the efficacy and safety of sequential immunosuppressive therapy in patients with non-end-stage IgA nephropathy (IgAN) with Lee's classification of IV ∼ V and provided evidence for the use of immunotherapy in patients with severe IgAN. Methods: We retrospectively analyzed the clinical data of patients with Lee's IV ∼ V non-end-stage IgA nephropathy. Results: 436 patients were diagnosed with IgAN, and 98 patients who met the inclusion criteria were included in this retrospective study. Of these, 17 were in the supportive care group, 20 in the P group (prednisone-only), 35 in P + CTX group (the prednisone combined with cyclophosphamide followed by mycophenolate mofetil), and 26 in the P + MMF group (prednisone combined with mycophenolate mofetil). The four groups showed differences in the segmental glomerulosclerosis score and the proportion of patients with Lee's grade IV (p < 0.05), but no differences in other indicators. Compared with the baseline values, urine protein-to-creatinine ratio (PCR) significantly decreased and serum albumin increased (p < 0.05), but there was no significant difference between the groups. The estimated Glomerular Filtration Rate (eGFR) of the P, P + MMF, and P + CTX groups were higher than that of the supportive care group at the 6th and 24th month after treatment (all p < 0.05). At the 24th month, the eGFR in the P + CTX group was higher than that in the P + MMF group (p < 0.05). The effective remission rate of the P + CTX group was higher than that of the supportive care group (p < 0.05). At 12 months, the effective remission rate of the P group was higher than that of the supportive care group (p < 0.05). At the 24th month, there was no significant difference in the effective remission rates among the three groups (P, P + MMF, and P + CTX). Nine patients with severe IgA nephropathy reached the endpoint. Conclusion: This study showed that immunosuppressive therapy insevere IgAN patient scan effectively reduce urinary protein, increase albumin, and protect renal function in the early stages of IgAN. P + CTX is the most commonly used, which has a high effective remission rate of urine protein and a low incidence of end-point events.

Podocytes are likely the therapeutic target of IgA nephropathy with isolated hematuria: Evidence from repeat renal biopsy.

Background: The present study aimed to prove the progression of immunoglobulin A nephropathy (IgAN) patients with isolated hematuria based on repeat renal biopsy data for the first time. Methods: 29 IgAN patients with isolated hematuria who received repeat renal biopsies were analyzed retrospectively, while 29 non-isolated hematuria IgAN patients with similar age and background were randomly selected as the control group. Clinical parameters were collected at the time of biopsy. The treatment strategies (conservative treatment with RASS blocker or immunosuppressive treatment) were choosen according to the pathological results at the first renal biopsy. The activity and chronicity indexes of renal lesions were evaluated. Markers of cell inflammation and proliferation were tseted by immunochemistry. The ultrastructure of podocytes was observed by transmission electron microscopy (TEM). Podocyte and oxidative stress marker (NPHS2 and 4-HNE) were detected by immunofluorescence. Results: The IgAN patients with isolated hematuria had better clinical indicators than those with no-isolated hematuria, such as better renal function, higher albumin and lower uric acid. The interval between two biopsies in IgAN patients with isolated hematuria was 630 (interquartile range, 409.5-1,171) days. The hematuria of the patients decreased significantly from 30 (IQR, 4.00-35.00) RBC/ul in the first biopsy to 11 (IQR, 2.50-30.00) RBC/ul in the repeated biopsy (p < 0.05). The level of triglyceride decreased significantly (p < 0.05). The other clinical indicators were not statistically significant (p > 0.05). Deposits of IgA and C3 in the glomerulus were persistent. The activity index decreased, especially cellular crescent formation, while the chronicity index increased. The ultrastructure of podocytes was improved after treatment. The oxidative stress products of podocytes reduced after treatment. Conclusion: Although the clinical indicators of the IgAN patients with isolated hematuria were in the normal range, various acute and chronic pathological changes have occurred, and irreversible chronic changes have been progressing. Cell inflammation and proliferation persisted. Oxidative stress of podocytes was likely to be the therapeutic target. This study provided a strong basis for the progress of IgAN with isolated hematuria through pathological changes before and after treatment. This study will help clinicians recognize the harm of hematuria, change the traditional treatment concept, and help such patients get early treatment.

hUC-MSC transplantation therapy effects on lupus-prone MRL/lpr mice at early disease stages.

BACKGROUND: The efficacy of human umbilical cord mesenchymal stem cell (hUC-MSC) transplantation in treating systemic lupus erythematosus (SLE) has been confirmed by small-scale clinical trials. However, these trials focused on severe or refractory SLE, while few studies focused on mild SLE. Therefore, this study focused on the therapeutic effects of hUC-MSC transplantation in early-stage or mild MRL/lpr lupus model mice. METHODS: Commercially available hUC-MSCs were transplanted into 8-week-old MRL/lpr mice by tail vein injection. Flow cytometry was used to analyze B cells and their subsets in the peripheral blood. Further, plasma inflammatory factors, autoantibodies, and plasma biochemical indices were detected using protein chip technology and ELISA kits. In addition, pathological staining and immunofluorescence were performed to detect kidney injury in mice. RESULTS: hUC-MSC transplantation did not affect the mice's body weight, and both middle and high dose hUC-MSC transplantation (MD and HD group) actually reduced spleen weight. hUC-MSC transplantation significantly decreased the proportion of plasmablasts (PB), IgG1- PB, IgG1+ PB, IgG1+ memory B (MB) cells, IgG1+ DN MB, and IgG1+ SP MB cells. The hUC-MSC transplantation had significantly reduced plasma levels of inflammatory factors, such as TNF-α, IFN-γ, IL-6, and IL-13. Pathological staining showed that the infiltration of glomerular inflammatory cells was significantly reduced and that the level of glomerular fibrosis was significantly alleviated in hUC-MSC-transplanted mice. Immunofluorescence assays showed that the deposition of IgG and IgM antibodies in the kidneys of hUC-MSC-transplanted mice was significantly lower than in the control. CONCLUSION: hUC-MSC transplantation could inhibit the proliferation and differentiation of peripheral blood B cells in the early-stage of MRL/lpr mice, thereby alleviating the plasma inflammatory environment in mice, leading to kidney injury remission. The study provides a new and feasible strategy for SLE treatment.

Disrupted Alpha-Ketoglutarate Homeostasis: Understanding Kidney Diseases from the View of Metabolism and Beyond.

Alpha-ketoglutarate (AKG) is a key intermediate of various metabolic pathways including tricarboxylic acid (TCA) cycle, anabolic and catabolic reactions of amino acids, and collagen biosynthesis. Meanwhile, AKG also participates in multiple signaling pathways related to cellular redox regulation, epigenetic processes, and inflammation response. Emerging evidence has shown that kidney diseases like diabetic nephropathy and renal ischemia/reperfusion injury are associated with metabolic disorders. In consistence with metabolic role of AKG, further metabolomics study demonstrated a dysregulated AKG level in kidney diseases. Intriguingly, earlier studies during the years of 1980s and 1990s indicated that AKG may benefit wound healing and surgery recovery. Recently, interests on AKG are arising again due to its protective roles on healthy ageing, which may shed light on developing novel therapeutic strategies against age-related diseases including renal diseases. This review will summarize the physiological and pathological properties of AKG, as well as the underlying molecular mechanisms, with a special emphasis on kidney diseases.

Regulation of Mitochondrial Homeostasis and Nrf2 in Kidney Disease: Timing Is Critical.

Abnormal regulation of mitochondrial homeostasis plays a critical role in the progression of renal disease. Recent studies have shown that activation of nuclear factor erythroid 2-related factor 2 (Nrf2) has time-dependent protective effects, which can be explained by the differing regulation of mitochondrial homeostasis during the various stages of kidney disease. In this review, we summarize the mechanisms whereby mitochondrial homeostasis is regulated and the nature of the dysregulation of mitochondrial homeostasis in renal disease. In addition, we summarize the dual roles of Nrf2 in kidney disease by discussing the studies that have shown the importance of the timing of its activation in the regulation of mitochondrial homeostasis. This should provide a theoretical basis for therapeutic strategies aimed at activating Nrf2 in kidney disease.

Epithelial-mesenchymal transdifferentiation of renal tubular epithelial cells induced by urinary proteins requires the activation of PKC-α and ßI isozymes.

Proteinuria is a common feature for almost all glomerular diseases and reflects the severity of the glomerular lesion. The presence of a large amount of proteins in tubular fluid, however, may also contribute to the development of RIF (renal interstitial fibrosis). Endocytosis of albumin in proximal tubular cells triggers PKC (protein kinase C)-dependent generation of reactive oxygen species and secretion of chemokines. As a family including 12 isozymes, which PKC isozymes participate in RIF is still unclear. EMT (epithelial-mesenchymal transdifferentiation) of RTECs (renal tubular epithelial cells) plays a crucial role in the progress of RIF induced by proteinuria. In the present study, we investigated the role of classical PKC isozymes in the proteinuria-induced EMT of RTECs. Employing immunochemical staining, we found that PKC-α, -ßI and -ßII were expressed in glomerulus and in RTECs in both normal and diseased renal tissues, while PKC-γ was only expressed in podocytes in the glomerulus. Treatment of HK-2 cells with extracted urinary proteins resulted in EMT, as evidenced by morphological changes, decreased E-cadherin expression, increased α-SMA (α-smooth muscle actin) expression, as well as production of type I collagen and fibronectin. Western blot analysis of PKC isozymes in the cytosolic compared with membrane fraction revealed translocation of PKC-α and -ßI, but not PKC-ßII, in HK-2 cells undergoing EMT. Pretreatment with selective PKC-α inhibitor G-6976 or PKC-ß inhibitor significantly attenuated EMT induced by urinary proteins. In summary, the present study suggested that PKC-α and -ßI play critical roles in the EMT of RTECs in response to urinary proteins.

High-Fat Diet-Induced Renal Proximal Tubular Inflammatory Injury: Emerging Risk Factor of Chronic Kidney Disease.

Nowadays, with the improvements in living standards and changes in living habits, high-fat diet (HFD) has become much more common in the populations worldwide. Recent studies have shown that HFD could induce lipid accumulation, and structural and functional abnormalities, accompanied by the release of large amounts of pro-inflammatory cytokines, in proximal tubular epithelial cells (PTECs). These findings indicate that, as an emerging risk factor, PTEC injury-induced by HFD may be closely related to inflammation; however, the potential mechanisms underlying this phenomenon is still not well-known, but may involve the several inflammatory pathways, including oxidative stress-related signaling pathways, mitochondrial dysfunction, the myeloid differentiation factor 2/Toll like receptor 4 (MD2/TLR4) signaling pathway, the ERK1/2-kidney injury molecule 1 (KIM-1)-related pathway, and nuclear factor-κB (NF-κB) activation, etc., and the detailed molecular mechanisms underlying these pathways still need further investigated in the future. Based on lipid abnormalities-induced inflammation is closely related to the development and progression of chronic kidney disease (CKD), to summarize the potential mechanisms underlying HFD-induced renal proximal tubular inflammatory injury, may provide novel approaches for CKD treatment.

Thiazolidinedione attenuate proteinuria and glomerulosclerosis in Adriamycin-induced nephropathy rats via slit diaphragm protection.

AIM: The slit diaphragm (SD) of podocyte impairment contributes to massive proteinuria and progressive glomerulosclerosis in many human glomerular diseases. The aim of the study was to determine if thiazolidinedione (TZD) reduce proteinuria and glomerulosclerosis in focal segmental glomerulosclerosis (FSGS) by preserving the structure and function of SD. METHODS: Adriamycin-induced FSGS rat models were employed. Urinary protein content was measured dynamically during the experiment. Additional biochemical parameters in serum samples were measured after the animals were killed. Glomerular sclerosis index (SI) and podocyte foot processes fusion rate (PFR) were evaluated. The protein and mRNA expressing levels of nephrin, podocin and CD2-associated protein (CD2AP) in glomeruli were assessed by immunohistochemistry and real-time quantitative polymerase chain reaction, respectively. The density of podocytes was also evaluated after anti-Wilms' tumour-1 immunohistochemical staining. RESULTS: Rosiglitazone treatment partially reduced proteinuria, but did not significantly affect the serum levels of triglyceride, cholesterol, albumin, glucose, urea nitrogen and creatinine in Adriamycin-induced FSGS rats. Glomerular SI and podocyte foot PFR were significantly attenuated by rosiglitazone treatment. Rosiglitazone prevented the reduction of nephrin, podocin and CD2AP protein expression induced by Adriamycin, however, the mRNA expression levels of these SD-related markers did not change significantly. Rosiglitazone therapy did not reverse Adriamycin-mediated reduction of the density of podocytes. CONCLUSIONS: The study data suggest that TZD are promising therapeutic agents on FSGS, and the mechanism may be mediated in part by directly protecting the structure and function of SD.

IgA nephropathy patients with partial crescent formation benefit from immunosuppressants: evidence from repeat renal biopsy.

BACKGROUND: Crescent formation is a serious pathological change in the IgA nephropathy (IgAN) which is believed to be primarily mediated by a mixture of parietal epithelial cells, macrophages, and myofibroblasts. It was recommended that IgAN patients with rapid renal hypofunction with a crescent body >50% should begin treatment with corticosteroids combined with cyclophosphamide. However, for patients with partial crescent formation, whether immunosuppressive therapy is necessary is a contested topic. MATERIALS AND METHODS: Data from IgAN patients with partial crescent formation who underwent repeat renal biopsy were retrospectively analyzed. RESULTS: From the first to the second renal biopsy, the mean hemoglobin level and albumin level increased significantly (P < 0.05), and uric acid and triglyceride levels decreased significantly (P < 0.05). Also, the 24-hour urinary protein excretion decreased significantly (P < 0.001), but no differences in blood pressure, creatinine level, or estimated glomerular filtration rate. For pathological indices, there were no differences in fluorescence intensity of IgA or C3 deposition (P > 0.05), but the mesangial cell proliferation decreased significantly (P < 0.05), and the proportions of global glomerulosclerosis and tubulointerstitial fibrosis increased significantly (P < 0.05, respectively). In addition, a decreased tendency in the proportion of crescent formation was observed in the second renal biopsy. CONCLUSIONS: Immunosuppressive therapy for IgAN patients with partial crescent formation can reduce proteinuria, stabilize renal function, improve anemia, and mitigate acute kidney injury in the short term.

The expression of renal Epstein-Barr virus markers in patients with lupus nephritis.

The aim of this study was to investigate the role of renal Epstein-Barr virus (EBV) infection in the pathogenesis of lupus nephritis (LN). A total of 58 renal tissue samples from patients with LN, seven normal renal tissue samples from patients with non-glomerular hematuria and 37 renal tissue samples from patients with minimal change nephropathy were collected. The expression of EBV-latent membrane protein-1 (EBV-LMP1) and EBV-encoded RNA 1 (EBER-1) in the renal tissue was examined by immunohistochemistry (IHC) and in situ hybridization (ISH), respectively. The sera levels of anti-nuclear antibody as well as antibodies to extractable nuclear antigen in patients with LN were also measured. An equivalence test showed that the results from the IHC and the ISH analyses had strong agreement. The positive rates of renal EBER-1 and EBV-LMP1 in the LN patients were significantly higher than those of the normal and minimal change nephropathy patients (P<0.001), while no significant difference was identified between those of the normal and minimal change nephropathy groups (P>0.05). The positive rates of EBV-LMP1 and EBER-1 in the renal tissues of patients with LN were not determined to be significantly different between the relapse (immunosuppressant-treated) and initial onset (non-treated) patients, between the patients with and without concurrent infection, and among the patients with different age ranges (P>0.05). The proportion of LN patients positive for anti-Sm antibody was significantly higher in the renal EBV-positive group than in the EBV-negative group (P<0.05), while the proportions of LN patients positive for the other autoantibodies that were examined were not identified to be significantly different between these two groups (P>0.05). The present study shows that renal EBV infection may contribute to the pathogenesis of LN by inducing anti-Sm antibody production.