LTBP4 Protects Against Renal Fibrosis via Mitochondrial and Vascular Impacts.

BACKGROUND: As a part of natural disease progression, acute kidney injury (AKI) can develop into chronic kidney disease via renal fibrosis and inflammation. LTBP4 (latent transforming growth factor beta binding protein 4) regulates transforming growth factor beta, which plays a role in renal fibrosis pathogenesis. We previously investigated the role of LTBP4 in chronic kidney disease. Here, we examined the role of LTBP4 in AKI. METHODS: LTBP4 expression was evaluated in human renal tissues, obtained from healthy individuals and patients with AKI, using immunohistochemistry. LTBP4 was knocked down in both C57BL/6 mice and human renal proximal tubular cell line HK-2. AKI was induced in mice and HK-2 cells using ischemia-reperfusion injury and hypoxia, respectively. Mitochondrial division inhibitor 1, an inhibitor of DRP1 (dynamin-related protein 1), was used to reduce mitochondrial fragmentation. Gene and protein expression were then examined to assess inflammation and fibrosis. The results of bioenergetic studies for mitochondrial function, oxidative stress, and angiogenesis were assessed. RESULTS: LTBP4 expression was upregulated in the renal tissues of patients with AKI. Ltbp4-knockdown mice showed increased renal tissue injury and mitochondrial fragmentation after ischemia-reperfusion injury, as well as increased inflammation, oxidative stress, and fibrosis, and decreased angiogenesis. in vitro studies using HK-2 cells revealed similar results. The energy profiles of Ltbp4-deficient mice and LTBP4-deficient HK-2 cells indicated decreased ATP production. LTBP4-deficient HK-2 cells exhibited decreased mitochondrial respiration and glycolysis. Human aortic endothelial cells and human umbilical vein endothelial cells exhibited decreased angiogenesis when treated with LTBP4-knockdown conditioned media. Mitochondrial division inhibitor 1 treatment ameliorated inflammation, oxidative stress, and fibrosis in mice and decreased inflammation and oxidative stress in HK-2 cells. CONCLUSIONS: Our study is the first to demonstrate that LTBP4 deficiency increases AKI severity, consequently leading to chronic kidney disease. Potential therapies focusing on LTBP4-associated angiogenesis and LTBP4-regulated DRP1-dependent mitochondrial division are relevant to renal injury.

Banff-based histologic chronicity index is associated with graft failure but has poor interobserver reproducibility.

BACKGROUND: Antibody-mediated rejection (AMR) often leads to chronic kidney allograft damage and is a critical cause of allograft failure. The Banff classification, used to diagnose AMR, has become complex and challenging for clinicians. A Banff-based histologic chronicity index (CI) was recently proposed as a simplified prognostic indicator. Its reliability and reproducibility have not been externally validated. METHODS: This study investigated 71 kidney allograft biopsies diagnosed with AMR. Interobserver reproducibility of the recently proposed CI and its components (cg, cv, ct, and ci) were assessed. The association between CI and allograft failure was analyzed, and CI cut-off values were evaluated by Cox proportional hazards regression and Kaplan-Meier estimator with log-rank test. RESULTS: The study confirmed the association of CI with allograft failure, but also revealed that the assessment of CI varied between pathologists, impacting its reproducibility as a prognostic tool. Only 49 (69.0%) of the biopsies showed complete agreement on the proposed cut-off value of CI < 4 or CI ≥ 4. Furthermore, this cut-off did not reliably stratify allograft failure. Notably, the cg score, which carries significant weight in the CI calculation, had the lowest agreement between observers (kappa = .281). CONCLUSIONS: While a simplified prognostic indicator for AMR is needed, this study highlights the limitations of CI, particularly its poor interobserver reproducibility. Our findings suggest that clinicians should interpret CI cautiously and consider establishing their own cut-off values. This study underscores the need to address interobserver reproducibility before CI can be widely adopted for AMR management.

Selective inhibition of HDAC6 promotes bladder cancer radiosensitization and mitigates the radiation-induced CXCL1 signalling.

BACKGROUND: Although trimodality therapy resecting tumours followed by chemoradiotherapy is emerged for muscle-invasive bladder cancer (MIBC), chemotherapy produces toxicities. Histone deacetylase inhibitors have been identified as an effective strategy to enhance cancer radiotherapy (RT). METHODS: We examined the role of HDAC6 and specific inhibition of HDAC6 on BC radiosensitivity by performing transcriptomic analysis and mechanism study. RESULTS: HDAC6 knockdown or HDAC6 inhibitor (HDAC6i) tubacin exerted a radiosensitizing effect, including decreased clonogenic survival, increased H3K9ac and α-tubulin acetylation, and accumulated γH2AX, which are similar to the effect of panobinostat, a pan-HDACi, on irradiated BC cells. Transcriptomics of shHDAC6-transduced T24 under irradiation showed that shHDAC6 counteracted RT-induced mRNA expression of CXCL1, SERPINE1, SDC1 and SDC2, which are linked to cell migration, angiogenesis and metastasis. Moreover, tubacin significantly suppressed RT-induced CXCL1 and radiation-enhanced invasion/migration, whereas panobinostat elevated RT-induced CXCL1 expression and invasion/migration abilities. This phenotype was significantly abrogated by anti-CXCL1 antibody, indicating the key regulator of CXCL1 contributing to BC malignancy. Immunohistochemical evaluation of tumours from urothelial carcinoma patients supported the correlation between high CXCL1 expression and reduced survival. CONCLUSION: Unlike pan-HDACi, the selective HDAC6i can enhance BC radiosensitization and effectively inhibit RT-induced oncogenic CXCL1-Snail-signalling, thus further advancing its therapeutic potential with RT.

ER ribosomal-binding protein 1 regulates blood pressure and potassium homeostasis by modulating intracellular renin trafficking.

BACKGROUND: Genome-wide association studies (GWASs) have linked RRBP1 (ribosomal-binding protein 1) genetic variants to atherosclerotic cardiovascular diseases and serum lipoprotein levels. However, how RRBP1 regulates blood pressure is unknown. METHODS: To identify genetic variants associated with blood pressure, we performed a genome-wide linkage analysis with regional fine mapping in the Stanford Asia-Pacific Program for Hypertension and Insulin Resistance (SAPPHIRe) cohort. We further investigated the role of the RRBP1 gene using a transgenic mouse model and a human cell model. RESULTS: In the SAPPHIRe cohort, we discovered that genetic variants of the RRBP1 gene were associated with blood pressure variation, which was confirmed by other GWASs for blood pressure. Rrbp1- knockout (KO) mice had lower blood pressure and were more likely to die suddenly from severe hyperkalemia caused by phenotypically hyporeninemic hypoaldosteronism than wild-type controls. The survival of Rrbp1-KO mice significantly decreased under high potassium intake due to lethal hyperkalemia-induced arrhythmia and persistent hypoaldosteronism, which could be rescued by fludrocortisone. An immunohistochemical study revealed renin accumulation in the juxtaglomerular cells of Rrbp1-KO mice. In the RRBP1-knockdown Calu-6 cells, a human renin-producing cell line, transmission electron and confocal microscopy revealed that renin was primarily retained in the endoplasmic reticulum and was unable to efficiently target the Golgi apparatus for secretion. CONCLUSIONS: RRBP1 deficiency in mice caused hyporeninemic hypoaldosteronism, resulting in lower blood pressure, severe hyperkalemia, and sudden cardiac death. In juxtaglomerular cells, deficiency of RRBP1 reduced renin intracellular trafficking from ER to Golgi apparatus. RRBP1 is a brand-new regulator of blood pressure and potassium homeostasis discovered in this study.

Pediatric glomerulopathy after COVID-19 vaccination: A case series and review of the literature.

BACKGROUND: Cases of glomerulopathy after COVID-19 vaccination have been reported in the adult population, while only a few cases have been reported in children and adolescents. For better understanding of this association in pediatric population, we aimed to describe clinical course of patients with glomerulopathy within 60 days of COVID-19 vaccination who were under followed up in the pediatric nephrology department of National Taiwan University Children's Hospital. METHODS: We reviewed the clinical characteristics, vaccine types, and outcomes of patients with newly diagnosed glomerular diseases or relapse of underlying glomerulopathy within 60 days after COVID-19 vaccination at our facility between January 2021 and July 2022. RESULTS: Thirteen pediatric patients were found to have newly diagnosed glomerular diseases or relapse from their underlying glomerulopathy after receiving their first, second, or third COVID-19 vaccines in our facility. Of the five pediatric patients with newly diagnosed glomerulopathy after vaccination, thin basement membrane nephropathy, idiopathic nephrotic syndrome, and hematuria have been identified. Seven patients had relapse episodes of underlying nephrotic syndrome and one patient with underlying isolated microscopic hematuria developed subnephrotic proteinuria after COVID-19 vaccination. All patients experienced remission or improvement with either immunosuppressive or conservative treatment during the follow-up period. CONCLUSIONS: This is the largest case series to date of pediatric glomerulopathy after COVID-19 vaccination. From our report, patients with either newly diagnosed or relapse of glomerulopathy after vaccination had good outcomes, and receiving vaccination to prevent COVID-19 infection or complications should be encouraged in pandemic era under close monitoring kidney manifestations.

End-to-end interstitial fibrosis assessment of kidney biopsies with a machine learning-based model.

BACKGROUND: The extent of interstitial fibrosis in the kidney not only correlates with renal function at the time of biopsy but also predicts future renal outcome. However, its assessment by pathologists lacks good agreement. The aim of this study is to construct a machine learning-based model that enables automatic and reliable assessment of interstitial fibrosis in human kidney biopsies. METHODS: Validated cortex, glomerulus and tubule segmentation algorithms were incorporated into a single model to assess the extent of interstitial fibrosis. The model performances were compared with expert renal pathologists and correlated with patients' renal functional data. RESULTS: Compared with human raters, the model had the best agreement [intraclass correlation coefficient (ICC) 0.90] to the reference in 50 test cases. The model also had a low mean bias and the narrowest 95% limits of agreement. The model was robust against colour variation on images obtained at different times, through different scanners, or from outside institutions with excellent ICCs of 0.92-0.97. The model showed significantly better test-retest reliability (ICC 0.98) than humans (ICC 0.76-0.94) and the amount of interstitial fibrosis inferred by the model strongly correlated with 405 patients' serum creatinine (r = 0.65-0.67) and estimated glomerular filtration rate (r = -0.74 to -0.76). CONCLUSIONS: This study demonstrated that a trained machine learning-based model can faithfully simulate the whole process of interstitial fibrosis assessment, which traditionally can only be carried out by renal pathologists. Our data suggested that such a model may provide more reliable results, thus enabling precision medicine.

Spectrum of cancer patients receiving renal biopsy.

BACKGROUND: The frontier of onco-nephrology, particularly renal complications of cancer and treatment, remains unexplored. We revisit the fundamental tool of diagnosing kidney disease, renal biopsy, in cancer patients with renal manifestation. METHODS: Patients who received renal biopsy from July 2015 to July 2019 were analyzed. Primary outcomes included end-stage renal disease (ESRD), mortality, and catastrophic outcome defined as either ESRD or mortality. A Cox proportional hazards model and Kaplan-Meier technique were used to assess the association with outcome measurements and survival analyses. Immunosuppression after renal biopsy and response to the treatment were evaluated. RESULTS: Among the 77 patients, the median age was 66 years (interquartile range [IQR] 59-73 years) and 46 (59.7%) were male. At the time of renal biopsy, 57 patients (74%) had various degrees of renal insufficiency. Tubulointerstitial damage score, quantified by renal pathology, were associated with higher hazards of ESRD (hazard ratio [HR], 1.77; 95% confidence interval [95% CI], 1.20 to 2.61; P = 0.004) and catastrophic outcome (HR, 1.30; 95% CI, 0.99 to 1.70; P = 0.058). The response rate to immunosuppression was lower in those diagnosed with tubulointerstitial nephritis (1 of 4 patients, 25%) than those with glomerulopathy (10 of 20 patients, 50%). CONCLUSION: Renal biopsy may improve diagnostic accuracy and assist in treatment guidance of cancer patients with renal manifestation. Renal biopsy should be encouraged with clinical indication. Collaboration between oncologists and nephrologists is of paramount importance to provide more comprehensive care for caner patients.

Distinguishing lupus lymphadenitis from Kikuchi disease based on clinicopathological features and C4d immunohistochemistry.

OBJECTIVES: Distinguishing Kikuchi disease (KD) from lupus lymphadenitis (LL) histologically is nearly impossible. We applied C4d immunohistochemical (IHC) stain to develop diagnostic tools. METHODS: We retrospectively investigated clinicopathological features and C4d IHC staining in an LL-enriched development cohort (19 LL and 81 KD specimens), proposed risk stratification criteria and trained machine learning models, and validated them in an external cohort (2 LL and 55 KD specimens). RESULTS: Clinically, we observed that LL was associated with an older average age (33 vs 25 years; P=0.005), higher proportion of biopsy sites other than the neck [4/19 (21%) vs 1/81 (1%); P=0.004], and higher proportion of generalized lymphadenopathy compared with KD [9/16 (56%) vs 7/31 (23%); P=0.028]. Histologically, LL involved a larger tissue area than KD did (P=0.006). LL specimens exhibited more frequent interfollicular pattern [5/19 (26%) vs 3/81 (4%); P=0.001] and plasma cell infiltrates (P=0.002), and less frequent histiocytic infiltrates in the necrotic area (P=0.030). Xanthomatous infiltrates were noted in 6/19 (32%) LL specimens. Immunohistochemically, C4d endothelial staining in the necrotic area [11/17 (65%) vs 2/62 (3%); P<10-7], and capillaries/venules [5/19 (26%) vs 7/81 (9%); P=0.048] and trabecular/hilar vessels [11/18 (61%) vs 8/81 (10%); P<10-4] in the viable area was more common in LL. During validation, both the risk stratification criteria and machine learning models were superior to conventional histological criteria. CONCLUSIONS: Integrating clinicopathological and C4d findings could distinguish LL from KD.

Two-year protocol biopsy after kidney transplantation in clinically stable recipients - a retrospective study.

The idea of protocol biopsy is to detect subclinical pathologies, including rejection, recurrent disease, or infection for early intervention and adjustment of immunosuppressants. Nevertheless, it is not adopted by most clinicians because of its low yield rate and uncertain long-term benefits. This retrospective study evaluated the impact of protocol biopsy on renal function and allograft survival. A two-year protocol biopsy was proposed for 190 stable patients; 68 of them accepted [protocol biopsy (PB) group], while 122 did not [nonprotocol biopsy (NPB) group]. The rejection diagnosis was made in 13 patients by protocol biopsy, and 11 of them had borderline rejection. In the following 5 years, graft survival was better in the PB group than in the NPB group (P = 0.0143). A total of 4 and 17 patients in the PB and NPB groups, respectively, had rejection events proven by indication biopsy. Renal function was better preserved in the PB group than in the NPB group (P = 0.0107) for patients with rejection events. Nevertheless, the survival benefit disappeared by a longer follow-up period (12-year, P = 0.2886). In conclusion, 2-year protocol biopsy detects subclinical pathological changes in rejection and preserves renal function by early intervention so as to prolong graft survival within 5 years.

PR-619, a General Inhibitor of Deubiquitylating Enzymes, Diminishes Cisplatin Resistance in Urothelial Carcinoma Cells through the Suppression of c-Myc: An In Vitro and In Vivo Study.

Cisplatin-based chemotherapy is the standard treatment for bladder urothelial carcinoma (UC). Most patients experience chemoresistance, the primary cause of treatment failure, which leads to disease relapse. The underlying mechanism of chemoresistance involves reduced apoptosis. In this study, we investigated the antitumor effect of the deubiquitylating enzyme inhibitor PR-619 in cisplatin-resistant bladder UC. Deubiquitinase (ubiquitin-specific protease 14 (USP14) and USP21) immunohistochemical staining demonstrated that deubiquitination is related to chemoresistance in patients with metastatic UC and may be a target for overcoming chemoresistance. Cytotoxicity and apoptosis were assessed using fluorescence-activated flow cytometry and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium assay, and PR-619 was found to enhance the cytotoxic and apoptotic effects of cisplatin in cisplatin-resistant T24/R cells. Mitigated cisplatin chemoresistance was associated with the concurrent suppression of c-Myc expression in T24/R cells. Moreover, the expression of c-Myc was upregulated in human bladder UC specimens from patients with chemoresistance. Experiments in a xenograft nude mouse model confirmed that PR-619 enhanced the antitumor effects of cisplatin. These results are promising for the development of therapeutic strategies to prevent UC chemoresistance through the combined use of chemotherapeutic agents/deubiquitination inhibitors (PR-619) by targeting the c-Myc pathway.

Prognostic factors for renal transplant graft survival in a retrospective cohort of 1000 cases: The role of desensitization therapy.

BACKGROUND: To review the results of renal transplantation after promulgation of the Human Organ Transplant Act in Taiwan in 1987, we conducted a retrospective study in the first 1000 cases performed in our hospital. Prognostic factors for graft survival were assessed with emphasis on the impact of donor-specific antibody (DSA). METHODS: Between January 1988 and April 2014, there were 1000 cases of renal transplantation performed in our hospital. Excluding 30 patients of ABO-incompatible transplantation, we reviewed 970 cases of ABO-compatible renal transplantation to analyze the prognostic factors for graft survival. The patients were grouped according to the dates of operations before (the Early group: 503 cases) and after (the Late group: 467 cases) the introduction of detection and desensitization of alloantibody in our hospital in 2004. RESULTS: The overall 5-year graft survival rate were 82.6%, which was significantly lower in the Early group (79.2%) than the Late group (86.3%) (p = 0.0012). The 1-year rejection-free survival was significantly lower in the Early group (78.3%) than the Late group (91.2%) (p = 0.0165). The difference between the two groups became insignificant when the time of observation extended beyond 12 months. In a multivariate regression model, we identified significant factors for poor graft survival, including HLA mismatches, delayed graft function with or without recovery, and antibody-mediate rejection (AMR). CONCLUSION: HLA mismatches, delayed graft function with or without recovery, and AMR were significant factors for poor graft survival. Detection and desensitization of DSA currently might be inadequate to improve the long-term outcome of renal transplantation.

The relationship of anti-phospholipase A2 receptor antibody and C5a complement with disease activity and short-term outcome in idiopathic membranous nephropathy.

BACKGROUND: The binding of anti-phospholipase A2 receptor (anti-PLA2R) antibody to podocyte and complement activation is the mechanisms of idiopathic membranous nephropathy (IMN). C5a, a complement activation end product, is a strong inflammatory cell stimulator and can influence the behavior of T cells and dendritic cells. This study examined the etiology-disease relationship and significance of auto-antibody and C5a with short-term remission. METHOD: Plasma anti-PLA2R antibody and C5a were measured with the blood samples that were collected when patients were admitted for renal biopsy. The deposition of IgA, IgG, IgM, C1q and C3c in glomerulus was graded according to immunofluorescence staining. The relationship of anti-PLA2R antibody with C5a, glomerular immunoglobulin and complement deposition was examined. Antibody and C5a levels as predictors of short-term remission were also examined. RESULTS: In 72 IMN patients, 50 patients had positive plasma anti-PLA2R antibody. The antibody had positive correlation to proteinuria. Patients with high grade IgG or C3c, but not IgA/IgM/C1q, deposition had higher anti-PLA2R antibody titers. C5a was increased in IMN patients, but had no correlation with anti-PLA2R antibody or proteinuria. The analysis revealed that C5a, not initial anti-PLA2R antibody, was a predictor associated with 12-month remission in patients receiving immunosuppression with multivariate-adjusted OR 0.74 (95% CI, 0.58-0.94, P = 0.01). CONCLUSION: This study provides indirect evidences of etiology-disease relationship of anti-PLA2R antibody in IMN patients. The role of C5a, a predictor of remission, in the disease course of MN and the influences on inflammatory cells in MN patients is worth to be clarified.

High Concentration of C5a-Induced Mitochondria-Dependent Apoptosis in Murine Kidney Endothelial Cells.

Patients with a relapse of idiopathic nephrotic syndrome have significantly increased levels of serum complement component 5a (C5a), and proteinuria has been noted in mice treated with C5a via changes in permeability of kidney endothelial cells (KECs) in established animal models. However, the apoptosis of KECs treated with high concentrations of C5a has also been observed. As mitochondrial damage is known to be important in cell apoptosis, the aim of this study was to examine the association between C5a-induced mouse KEC apoptosis and mitochondrial damage. Mouse KECs were isolated and treated with different concentrations of C5a. Cell viability assays showed that a high-concentration mouse recombinant protein C5a (rmC5a) treatment reduced mouse KEC growth. Cell cycle phase analysis, including apoptosis (sub-G1 phase) showed an increased percentage of the subG1 phase with a high-concentration rmC5a treatment. Cytochrome c and caspase 3/9 activities were significantly induced in the mouse KECs after a high-dose rmC5a (50 ng/mL) treatment, and this was rescued by pretreatment with the C5a receptor (C5aR) inhibitor (W-54011) and N-acetylcysteine (NAC). Reactive oxygen species (ROS) formation was detected in C5a-treated mouse KECs; however, W-54011 or NAC pretreatment inhibited high-dose rmC5a-induced ROS formation and also reduced cytochrome c release, apoptotic cell formation, and apoptotic DNA fragmentation. These factors determined the apoptosis of mouse KECs treated with high-dose C5a through C5aR and subsequently led to apoptosis via ROS regeneration and cytochrome c release. The results showed that high concentrations of C5a induced mouse KEC apoptosis via a C5aR/ROS/mitochondria-dependent pathway. These findings may shed light on the potential mechanism of glomerular sclerosis, a process in idiopathic nephrotic syndrome causing renal function impairment.

Histone Deacetylase Inhibitor, Trichostatin A, Synergistically Enhances Paclitaxel-Induced Cytotoxicity in Urothelial Carcinoma Cells by Suppressing the ERK Pathway.

Trichostatin A (TSA), an antifungal antibiotic derived from Streptomyces, inhibits mammalian histone deacetylases, and especially, selectively inhibits class I and II histone deacetylase (HDAC) families of enzymes. TSA reportedly elicits an antiproliferative response in multifarious tumors. This study investigated the antitumor effects of TSA alone and in combination with paclitaxel when applied to two high-grade urothelial carcinoma (UC) cell lines (BFTC-905 and BFTC-909). Fluorescence-activated cell sorting, flow cytometry, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium assay were used to assess TSA's cytotoxicity and effects on apoptosis induction. TSA induced synergistic cytotoxicity, when combined with paclitaxel (combination index < 1), resulted in concomitant suppression of paclitaxel-induced activation of phospho-extracellular signal-regulated kinase (ERK) 1/2. A xenograft nude mouse model confirmed that TSA enhances the antitumor effects of paclitaxel. These findings demonstrate that the administration of TSA in combination with paclitaxel elicits a synergistic cytotoxic response. The results of this study indicate that the chemoresistance of UC could be circumvented by combining HDAC inhibitors to target the ERK pathway.

Trifluoperazine, an Antipsychotic Drug, Effectively Reduces Drug Resistance in Cisplatin-Resistant Urothelial Carcinoma Cells via Suppressing Bcl-xL: An In Vitro and In Vivo Study.

Cisplatin-based chemotherapy is the primary treatment for metastatic bladder urothelial carcinoma (UC). Most patients inevitably encounter drug resistance and resultant disease relapse. Reduced apoptosis plays a critical role in chemoresistance. Trifluoperazine (TFP), an antipsychotic agent, has demonstrated antitumor effects on various cancers. This study investigated the efficacy of TFP in inhibiting cisplatin-resistant bladder UC and explored the underlying mechanism. Our results revealed that cisplatin-resistant UC cells (T24/R) upregulated the antiapoptotic factor, B-cell lymphoma-extra large (Bcl-xL). Knockdown of Bcl-xL by siRNA resensitized cisplatin-resistant cells to the cisplatin cytotoxic effect. TFP (10-45 µM) alone elicited dose-dependent cytotoxicity, apoptosis, and G0/G1 arrest on T24/R cells. Co-treatment of TFP potentiated cisplatin-induced cytotoxicity in T24/R cells. The phenomenon that TFP alleviated cisplatin resistance to T24/R was accompanied with concurrent suppression of Bcl-xL. In vivo models confirmed that TFP alone effectively suppressed the T24/R xenograft in nude mice. TFP co-treatment enhanced the antitumor effect of cisplatin on the T24/R xenograft. Our results demonstrated that TFP effectively inhibited cisplatin-resistant UCs and circumvented cisplatin resistance with concurrent Bcl-xL downregulation. These findings provide a promising insight to develop a therapeutic strategy for chemoresistant UCs.

MLN4924, a Protein Neddylation Inhibitor, Suppresses the Growth of Human Chondrosarcoma through Inhibiting Cell Proliferation and Inducing Endoplasmic Reticulum Stress-Related Apoptosis.

Chondrosarcoma, a heterogeneous malignant bone tumor, commonly produces cartilage matrix, which generally has no response to conventional therapies. Studies have reported that MLN4924, a NEDD8-activating enzyme inhibitor, achieves antitumor effects against numerous malignancies. In this study, the suppressive effects of MLN4924 on human chondrosarcoma cell lines were investigated using in vitro and in vivo assays, which involved measuring cell viability, cytotoxicity, apoptosis, proliferation, cell cycles, molecule-associated cell cycles, apoptosis, endoplasmic reticulum (ER) stress, and tumor growth in a xenograft mouse model. Our results demonstrated that MLN4924 significantly suppressed cell viability, exhibited cytotoxicity, and stimulated apoptosis through the activation of caspase-3 and caspase-7 in chondrosarcoma cell lines. Furthermore, MLN4924 significantly inhibited cell proliferation by diminishing the phosphorylation of histone H3 to cause G2/M cell cycle arrest. In addition, MLN4924 activated ER stress⁻related apoptosis by upregulating the phosphorylation of c-Jun N-terminal kinase (JNK), enhancing the expression of GRP78 and CCAAT-enhancer-binding protein homologous protein (CHOP, an inducer of endoplasmic ER stress⁻related apoptosis) and activating the cleavage of caspase-4. Moreover, MLN4924 considerably inhibited the growth of chondrosarcoma tumors in a xenograft mouse model. Finally, MLN4924-mediated antichondrosarcoma properties can be accompanied by the stimulation of ER stress⁻related apoptosis, implying that targeting neddylation by MLN4924 is a novel therapeutic strategy for treating chondrosarcoma.

Inhibition of Rho-associated kinase relieves C5a-induced proteinuria in murine nephrotic syndrome.

Childhood nephrotic syndrome is mainly caused by minimal change disease which is named because only subtle ultrastructural alteration could be observed at electron microscopic level in the pathological kidney. Glomerular podocytes are presumed to be the target cells whose protein sieving capability is compromised by a yet unidentified permeability perturbing factor. In a cohort of children with non-hereditary idiopathic nephrotic syndrome, we found the complement fragment C5a was elevated in their sera during active disease. Administration of recombinant C5a induced profound proteinuria and minimal change nephrotic syndrome in mice. Purified glomerular endothelial cells, instead of podocytes, were demonstrated to be responsible for the proteinuric effect elicited by C5a. Further studies depicted a signaling pathway involving Rho/Rho-associated kinase/myosin activation leading to endothelial cell contraction and cell adhesion complex breakdown. Significantly, application of Rho-associated kinase inhibitor, Y27632, prevented the protein leaking effects observed in both C5a-treated purified endothelial cells and mice. Taken together, our study identifies a previously unknown mechanism underlying nephrotic syndrome and provides a new insight toward identifying Rho-associated kinase inhibition as an alternative therapeutic option for nephrotic syndrome.

Repeated cycles of high-dose intravenous immunoglobulin and plasmapheresis for treatment of late antibody-mediated rejection of renal transplants.

BACKGROUND/PURPOSE: Intravenous immunoglobulin (IVIG) plays a central role in the treatment of antibody-mediated rejection (AMR) of renal allografts, but the treatment outcomes for late AMR (>6 months after transplantation) are poor. METHODS: We performed a retrospective study to assess the response patterns of IVIG-based (2 g/kg) desensitization for late AMR. Patients who received desensitization after the pathological diagnosis of late AMR positive for complement component C4d were grouped as the Desensitized Group and compared to a historical Control Group with complement component C4d positivity in retrospective stainings. RESULTS: The 10-year graft survival of the Desensitized Group (73.9%, n = 35) was significantly better than that of the historical Control Group (35.0%, n = 40) without desensitization. In the Desensitized Group, a subgroup of patients (D2 Subgroup, n = 11), who responded to desensitization initially but deteriorated later, was identified to benefit from repeated cycles of desensitization at 31.1 ± 20.9 months. Patients receiving only one cycle of desensitization were further grouped into D1-good (n = 10) and D1-poor (n = 14) based on their long-term renal function. The D2 Subgroup patients did not exhibit significant improvements in renal function compared to the D1-poor patients, until 30 months after IVIG-based desensitization, suggesting desensitization therapy has a working window of approximately 24 months. CONCLUSION: Repeated cycles of IVIG-based desensitization help stabilize long-term renal function in patients with persistent AMR.

Titanium nanoparticle inhalation induces renal fibrosis in mice via an oxidative stress upregulated transforming growth factor-ß pathway.

Titanium dioxide nanoparticles (Nano-TiO2) are gradually being used extensively in clinical settings, industry, and daily life. Accumulation studies showed that Nano-TiO2 exposure is able to cause injuries in various animal organs, including the lung, liver, spleen, and kidney. However, it remains unclear whether exposure of Nano-TiO2 by inhalation causes renal fibrosis. Here, we investigated the role of reactive oxygen species (ROS)/reactive nitrogen species (RNS) related signaling molecules in chronic renal damage after Nano-TiO2 inhalation in mice. Mice were treated with Nano-TiO2 (0.1, 0.25, and 0.5 mg/week) or microparticle-TiO2 (0.5 mg/week) by nonsurgical intratracheal instillation for 4 weeks. The results showed that Nano-TiO2 inhalation increased renal pathological changes in a dose-dependent manner. No renal pathological changes were observed in microparticle-TiO2-instilled mice. Nano-TiO2 (0.5 mg/week) possessed the ability to precipitate in the kidneys, determined by transmission electron microscopy and increased serum levels of blood urea nitrogen. The expressions of markers of ROS/RNS and renal fibrosis markers, including nitrotyrosine, inducible nitric oxide synthase, hypoxia inducible factor-1α (HIF-1α), heme oxygenase 1, transforming growth factor-ß (TGFß), and collagen I, determined by immunohistochemical staining were increased in the kidneys. Furthermore, Nano-TiO2-induced renal injury could be mitigated by iNOS inhibitor aminoguanidine and ROS scavenger N-acetylcysteine treatment in transcription level. The in vitro experiments showed that Nano-TiO2 significantly and dose-dependently increased the ROS production and the expressions of HIF-1α and TGFß in human renal proximal tubular cells, which could be reversed by N-acetylcysteine treatment. Taken together, these results suggest Nano-TiO2 inhalation might induce renal fibrosis through a ROS/RNS-related HIF-1α-upregulated TGF-ß signaling pathway.