A dynamic online nomogram for predicting renal outcomes of idiopathic membranous nephropathy.

BACKGROUND: Because spontaneous remission is common in IMN, and there are adverse effects of immunosuppressive therapy, it is important to assess the risk of progressive loss of renal function before deciding whether and when to initiate immunosuppressive therapy. Therefore, this study aimed to establish a risk prediction model to predict patient prognosis and treatment response to help clinicians evaluate patient prognosis and decide on the best treatment regimen. METHODS: From September 2019 to December 2020, a total of 232 newly diagnosed IMN patients from three hospitals in Liaoning Province were enrolled. Logistic regression analysis selected the risk factors affecting the prognosis, and a dynamic online nomogram prognostic model was constructed based on extreme gradient boost, random forest, logistic regression machine learning algorithms. Receiver operating characteristic and calibration curves and decision curve analysis were utilized to assess the performance and clinical utility of the developed model. RESULTS: A total of 130 patients were in the training cohort and 102 patients in the validation cohort. Logistic regression analysis identified four risk factors: course ≥ 6 months, UTP, D-dimer and sPLA2R-Ab. The random forest algorithm showed the best performance with the highest AUROC (0.869). The nomogram had excellent discrimination ability, calibration ability and clinical practicability in both the training cohort and the validation cohort. CONCLUSIONS: The dynamic online nomogram model can effectively assess the prognosis and treatment response of IMN patients. This will help clinicians assess the patient's prognosis more accurately, communicate with the patient in advance, and jointly select the most appropriate treatment plan.

Cut-off values of haemoglobin and clinical outcomes in incident peritoneal dialysis: the PDTAP study.

BACKGROUND: To explore the cut-off values of haemoglobin (Hb) on adverse clinical outcomes in incident peritoneal dialysis (PD) patients based on a national-level database. METHODS: The observational cohort study was from the Peritoneal Dialysis Telemedicine-assisted Platform (PDTAP) dataset. The primary outcomes were all-cause mortality, major adverse cardiovascular events (MACE) and modified MACE (MACE+). The secondary outcomes were the occurrences of hospitalization, first-episode peritonitis and permanent transfer to haemodialysis (HD). RESULTS: A total of 2591 PD patients were enrolled between June 2016 and April 2019 and followed up until December 2020. Baseline and time-averaged Hb <100 g/l were associated with all-cause mortality, MACE, MACE+ and hospitalizations. After multivariable adjustments, only time-averaged Hb <100 g/l significantly predicted a higher risk for all-cause mortality {hazard ratio [HR] 1.83 [95% confidence interval (CI) 1.19-281], P = .006}, MACE [HR 1.99 (95% CI 1.16-3.40), P = .012] and MACE+ [HR 1.77 (95% CI 1.15-2.73), P = .010] in the total cohort. No associations between Hb and hospitalizations, transfer to HD and first-episode peritonitis were observed. Among patients with Hb ≥100 g/l at baseline, younger age, female, use of iron supplementation, lower values of serum albumin and renal Kt/V independently predicted the incidence of Hb <100 g/l during the follow-up. CONCLUSION: This study provided real-world evidence on the cut-off value of Hb for predicting poorer outcomes through a nation-level prospective PD cohort.

LMCD1 is involved in tubulointerstitial inflammation in the early phase of renal fibrosis by promoting NFATc1-mediated NLRP3 activation.

Prolonged renal inflammation contributes to fibrosis, which may eventually lead to irreversible chronic kidney disease. Our previous work demonstrated that LIM and cysteine-rich domain 1 (LMCD1) are associated with renal interstitial fibrosis in a 21-day unilateral ureteral obstruction (21UUO) mouse model. Interestingly, based on the gene expression omnibus database, we found that LMCD1 is enhanced in the mouse kidney as early as 5, 7, and 10 days following unilateral ureteral obstruction (UUO), suggesting that LMCD1 may exert its function in an earlier phase. To validate this conjecture, a 7UUO mouse model and a tumor necrosis factor-α (TNF-α)-stimulated HK-2 cell model were established, followed by injection of adenovirus vectors carrying short hairpin RNA targeting LMCD1. LMCD1 silencing ameliorated renal collagen deposition and reduced the expression of profibrotic factors in the 7UUO model. LMCD1 silencing alleviated tubulointerstitial inflammation by mitigating F4/80+ cell infiltration, monocyte chemoattractant protein-1 release and nuclear factor-κB activation. In addition, LMCD1 silencing suppressed NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation and nuclear factor of activated T cells 1 (NFATc1) nuclear translocation. Consistent results were obtained in TNF-α-stimulated HK-2 cells in vitro. Mechanistically, the transcriptional coactivator LMCD1 cooperates with the transcription factor NFATc1 to increase NLRP3 expression. Collectively, these findings suggest that LMCD1 participates in tubulointerstitial inflammation via an LMCD1-NFATc1/NLRP3 mechanism. LMCD1 may therefore become a potential target for the control of renal inflammation and fibrosis.

LIM and Cysteine-Rich Domains 1 Promotes Transforming Growth Factor ß1-Induced Epithelial-Mesenchymal Transition in Human Kidney 2 Cells.

Renal fibrosis is the major pathologic manifestation of chronic kidney disease (CKD). LIM and cysteine-rich domains 1 (LMCD1) is upregulated in the kidney tissue from patients with CKD and the transforming growth factor ß1 (TGF-ß1)-treated human renal tubular epithelial cell line human kidney 2 (HK-2) (Gene Expression Omnibus: GSE66494 and GSE23338). Previously, we have demonstrated that the knockdown of LMCD1 ameliorated renal fibrosis in mice by blocking the activation of the extracellular signal-regulated kinase pathway. In this study, we sought to further investigate whether LMCD1 affects TGF-ß1-induced epithelial-mesenchymal transition (EMT) of kidney tubular epithelial cells and its potential role in the TGF-ß1/Smad signaling pathway. First, we confirmed that LMCD1 expression was increased in the fibrotic kidneys of patients with CKD compared with that in normal kidneys and that LMCD1 was predominantly localized in the renal tubules. LMCD1 and mesenchymal markers were upregulated in obstructed kidney tissues of mice at 21 days after unilateral ureteral obstruction surgery compared with the tissues in sham mice. Next, we demonstrated that TGF-ß1 significantly increased LMCD1 expression through Smad-mediated transcription in HK-2 cells in vitro. In turn, LMCD1 acted as a transcriptional coactivator of E2F transcription factor 1 to promote the transcription of TGF-ß1. Moreover, TGF-ß1 increased the interaction between LMCD1 and Smad ubiquitination regulatory factor 2 (Smurf2) and accelerated Smurf2-mediated LMCD1 degradation via the ubiquitination system. The knockdown of LMCD1 inhibited TGF-ß1-induced EMT in both HK-2 cells and unilateral ureteral obstruction mice. Our results indicate a positive feedback loop between TGF-ß1 and LMCD1 for EMT induction in HK-2 cells and that Smurf2 acts as a negative regulator in this process by accelerating LMCD1 degradation.

Telemedicine and Clinical Outcomes in Peritoneal Dialysis: A Propensity-Matched Study.

INTRODUCTION: Telemedicine (TM) has shown to provide potential benefits on clinical outcomes in patients with chronic kidney disease but limited evidences published in the peritoneal dialysis (PD) population. This study aimed to explore the long-term effects of TM on the mortality and technique failure. METHODS: The Peritoneal Dialysis Telemedicine-assisted Platform Cohort Study (PDTAP Study) was conducted prospectively in 27 hospitals in China since 2016. Patient and practice data were collected through the doctor-end of the TM app (Manburs) for all participants. TM including self-monitoring records, on-line education materials, and real-time physician-patient contact was only performed for the patient-end users of the Manburs. The primary outcome was all-cause mortality. The secondary outcomes were cause-specific mortality and all-cause and cause-specific permanent transfer to hemodialysis. RESULTS: A total of 7,539 PD patients were enrolled between June 2016 and April 2019, with follow-up till December 2020. Patients were divided into two cohorts: TM group (39.1%) and non-TM group (60.9%). A propensity score was used to create 2,160 matched pairs in which the baseline covariates were well-balanced. There were significantly lower risks of all-cause mortality (HR 0.59 [0.51, 0.67], p < 0.001), CVD mortality (HR 0.59 [0.49, 0.70], p < 0.001), all-cause transfer to hemodialysis (0.57 [0.48, 0.67], p < 0.001), transfer to hemodialysis from PD-related infection (0.67 [0.51, 0.88], p = 0.003), severe fluid overload (0.40 [0.30, 0.55], p < 0.001), inadequate solute clearance (0.49 [0.26, 0.92], p = 0.026), and catheter-related noninfectious complications (0.41 [0.17, 0.97], p = 0.041) in the TM group compared with the non-TM group. CONCLUSION: This study indicated real-world associations between TM usage and reduction in patient survival and technique survival through a multicenter prospective cohort.

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.

Late-Onset Bartter Syndrome Type II Due to a Novel Compound Heterozygous Mutation in KCNJ1 Gene: A Case Report and Literature Review.

Background: Bartter syndrome (BS) type II is a rare autosomal recessive renal tubular disorder caused by mutations in the KCNJ1 gene, which encodes the apical renal outer medullary potassium (ROMK) channel in the thick ascending limb (TAL) of Henle's loop. BS type II is typically considered as a disorder of infancy and seldom seen in adults. Case Presentation: A 34-year-old woman was admitted with generalized body numbness and hand convulsions, without growth retardation. Laboratory tests revealed hypokalemic metabolic alkalosis, hyperreninemic hyperaldosteronism, and nephrocalcinosis. She was misdiagnosed during the initial diagnosis process and was finally diagnosed with late-onset BS type II via genetic testing through next-generation sequencing combined with Sanger sequencing. A novel compound heterozygous p.Leu207Ile/p. Cys308Arg variant in exon 5 of the KCNJ1 gene from her parents was identified and speculated to be a potential pathogenic gene variation. Conclusion: We report a case of late-onset BS type II with a novel compound heterozygous mutation in KCNJ1. Both variants are novel and have never been reported. Our report will have a significant impact on the diagnosis of BS in other patients without typical clinical presentations and emphasizes the importance of genetic investigation.

Suppression of LMCD1 ameliorates renal fibrosis by blocking the activation of ERK pathway.

Tubulointerstitial fibrosis is a common pathway of chronic kidney disease (CKD) and is closely related to the progression of CKD. LMCD1, acting as an intermediary, has been reported to play a role in cardiac fibrosis. However, its role in renal fibrosis is yet to be deciphered. Based on the GEO database, we found the expression of LMCD1 is increased in kidney tissues of CKD patients and in human proximal tubular epithelial (HK-2) cells treated with transforming growth factor-ß1 (TGF-ß1), suggesting that LMCD1 may be involved in tubulointerstitial fibrosis. Herein, we investigated the role of LMCD1 in mice with unilateral ureteral obstruction (UUO) and in TGF-ß1-stimulated HK-2 cells. In the UUO model, the expression of LMCD1 was upregulated. UUO-induced renal histopathological changes were mitigated by knockdown of LMCD1. LMCD1 silence alleviated renal interstitial fibrosis in UUO mice by decreasing the expression of TGF-ß1, fibronectin, collagen I, and collagen III. LMCD1 deficiency suppressed cell apoptosis in kidney to prevent UUO-triggered renal injury. Furthermore, LMCD1 deficiency blocked the activation of ERK signaling in UUO mice. In vitro, LMCD1 was upregulated in HK-2 cells after TGF-ß1 stimulation. LMCD1 silence abrogated TGF-ß1-mediated upregulation of fibrotic genes. Treatment of HK-2 cells with ERK-specific inhibitor SCH772984 and agonist TPA validated LMCD1 exerted its function via activating ERK signaling. Together, our findings suggest that inhibition of LMCD1 protects against renal interstitial fibrosis by impeding ERK activation.

The Peritoneal Dialysis Telemedicine-assisted Platform Cohort (PDTAP) Study: Design and methods.

OBJECTIVES: The primary objective of the Peritoneal Dialysis Telemedicine-assisted Platform Cohort (PDTAP) Study is to explore potential predictors and their effects on patient survival, technique survival, and the occurrence of infectious and noninfectious complications. DESIGN: The PDTAP study is a national-level cohort study in China. A newly developed PD telemedicine application provided a unique and convenient way to collect multicenter, structured data across units. SETTING: The PDTAP study was underway in 27 hospitals from 14 provinces located at 7 geographical regions (northwest, northeast, north, central, southwest, southeast, and south) in China. PARTICIPANTS: Our study aims to enroll at least 7000 adult patients with end-stage renal disease receiving PD. METHODS: Approval has been obtained through the ethics committees of all hospitals. All participants signed the informed consent form after the center had received ethics board approval in accordance with the Declaration of Helsinki. MAIN OUTCOME MEASURES: Patient survival, technique survival, hospitalization, and the occurrence of infectious and noninfectious complications. CONCLUSIONS: The PDTAP study aims to explore potential predictors and their effects on patient survival, technique survival, and infectious and noninfectious complications using a newly developed PD telemedicine system to collect multicenter, structured data in real-world practice. Substantial and transformable findings in relation to PD practices were expected. This study also developed a national-level infrastructure for further collaboration and ancillary investigation.

Immunoglobulin a nephropathy as the first clinical presentation of Wilson disease: a case report and literature review.

BACKGROUND: Wilson disease (WD) is a rare genetic disorder of copper metabolism. Differences in copper tissue accumulation lead to various clinical manifestations, including some atypical presentations. The complex clinical features of WD make diagnosis challenging, delaying the best chance for treatment. CASE PRESENTATION: We report a case of a 26-year-old man with nephritis-range proteinuria and elevated serum creatinine. The renal pathology indicated immunoglobulin A (IgA) nephropathy and tubular injury, which was inconsistent with glomerular lesions. Cirrhosis was also detected by imaging examination. Considering both kidney injury and liver damage, WD was suspected. Based on results showing abnormal copper metabolism, corneal Kayser-Fleischer rings, and genetic disorders in the ATP7B gene, the patient was finally diagnosed with WD. After treatment with oral penicillamine, zinc sulfate and losartan, the patient showed alleviation of both WD and nephropathy after 3 years of follow-up. He maintained a good quality of daily life. CONCLUSION: This case highlights that unexplained neurological and liver symptoms in patients with IgA nephropathy can be clues for WD.

Periostin contributes to renal and cardiac dysfunction in rats with chronic kidney disease: Reduction of PPARα.

POSTN knockdown inhibits the formation of NLRP3 inflammasome in rat myocardium.Periostin (POSTN), an extracellular matrix protein, and peroxisome proliferator-activated receptor alpha (PPARα), a ligand-activated nuclear transcription factor, are reported to be involved in renal and cardiac dysfunction associated with chronic kidney disease (CKD), respectively. This study is performed to investigate how POSTN-PPARα axis affects the progress of CKD. In vivo, adenovirus particles containing POSTN short hairpin RNA (Ad-shPOSTN) were intravenously given to Sprague Dawley rats following 5/6 nephrectomy. The effects of Ad-shPOSTN on CKD and CKD-associated cardiovascular disease were evaluated. In vitro, NRK-52E renal tubular epithelial cells were infected with Ad-shPOSTN or Ad-POSTN (overexpression) to explore whether POSTN affected collagen deposition by regulating PPARα. We found that POSTN expression was upregulated, while PPARα was downregulated in the injured renal and left ventricular tissues of nephrectomized rats. Ad-shPOSTN improved renal function, prevented cardiac dysfunction, and attenuated organ fibrosis in nephrectomized rats. The expression levels of renal and myocardial PPARα were increased following Ad-shPOSTN administration. Furthermore, POSTN silencing suppressed the formation of NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome in the myocardium: the levels of NLRP3, anti-apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), cleaved caspase 1, mature interleukin (IL)-1ß and IL-18 were reduced. In NRK-52E cells, forced overexpression of POSTN directly inhibited PPARα expression and induced collagen deposition. WY14643, a PPARα agonist, suppressed POSTN-induced collagen deposition. In summary, our study demonstrates that POSTN negatively regulates PPARα expression. Targeting POSTN-PPARα axis may present a novel protective intervention to alleviate CKD and CKD-associated cardiac dysfunction.

Gut microbial metabolite TMAO contributes to renal dysfunction in a mouse model of diet-induced obesity.

Emerging evidence shows that obesity induces renal injury and is an independent risk factor for the development of chronic kidney disease (CKD), even without diabetes or hyperglycemia. Although multiple metabolic factors have been suggested to account for obesity-associated renal injury, the precious underlying mechanisms are not completely understood. Recent study shows that increased trimethylamine N-Oxide (TMAO), a gut microbiota-generated metabolite, directly contributes to renal interstitial fibrosis and dysfunction. Circulating TMAO is elevated in high-fat diets (HFD)-induced obese animals. Here we tested the hypothesis that elevated TMAO might play a contributory role in the development of renal dysfunction in a mouse model of HFD-induced obesity that mimics human obesity syndrome. Male C57BL/6 mice received either a low-fat diet (LFD) or a HFD, without or with 3,3-Dimethyl-1-butanol (DMB, a trimethylamine formation inhibitor) for 16 weeks. Compared with mice fed a LFD, mice fed a HFD developed obesity and metabolic disorders, and exhibited significantly elevated plasma TMAO levels at the end of the experiment. Molecular and morphological studies revealed that renal interstitial fibrosis, phosphorylation of SMAD3 (a key regulator of renal fibrosis), expression of kidney injury molecule-1 and plasma cystatin C were significantly increased in mice fed a HFD, compared with mice fed a LFD. Additionally, expression of NADPH oxidase-4 and pro-inflammatory cytokines tumor necrosis factor-α and interleukin-1 ß was also augmented in mice fed a HFD as compared to mice fed a LFD. These molecular and morphological alterations observed in mice fed a HFD were prevented by concomitant treatment with DMB, which reduced plasma TMAO levels. Furthermore, elevated circulating TMAO levels were positively correlated with increased renal interstitial fibrosis and expression of kidney injury molecule-1. Notable, there was no difference in blood pressure among groups, and DMB treatment had no effects on body weight and metabolic parameters. These data suggest that HFD-induced obesity leads to elevations in gut microbiota-generated metabolite TMAO in the circulation, which contributes to renal interstitial fibrosis and dysfunction by promoting renal oxidative stress and inflammation. These findings may provide new insights into the mechanisms underlying obesity-associated CKD. Targeting TMAO may be a novel strategy for prevention and treatment of CKD in patients with obesity.

Hepatitis B Virus X Protein Reduces Podocyte Adhesion via Downregulation of α3ß1 Integrin.

BACKGROUND/AIMS: Hepatitis B virus (HBV)-associated glomerulonephritis (HBV-GN) is characterized by a reduced number of podocytes due to apoptosis and shedding from the basement membrane. However, the pathological mechanism of HBV-GN is unclear. We previously showed that hepatitis B virus X protein (HBx) promotes apoptosis in tubular epithelial cells. In this study, we transfected podocytes with HBx and examined the effects on adhesion and apoptosis of these cells. METHODS: Podocytes were transfected with pc-DNA3.1 (+)-HBx. One control group was not transfected and another control group was transfected with empty plasmids. Podocyte adhesion was assessed by a fluorescence assay, apoptosis was measured by flow cytometry and fluorescence microscopy, and expression of α3ß1 integrin was determined by western blotting and the reverse transcription polymerase chain reaction (RT-PCR). Activity of caspase-8 was measured by a spectrophotometric assay. RESULTS: Relative to controls, podocytes with pc-DNA3.1(+)-HBx had reduced cell adhesion, increased apoptosis, reduced expression of α3ß1 integrin, and increased caspase-8 activity. ß1 integrin blockage reduced podocyte adhesion, but increased apoptosis and caspase-8 activity. Treatment of transfected podocytes with a caspase-8 inhibitor (Z-IETD-FMK) had no effect on the HBx-mediated integrin downregulation and reduced podocyte adhesion, suggesting that α3ß1 integrin downregulaton is sufficient to alter cell adhesion. CONCLUSIONS: Our in vitro results indicate that HBx reduced podocyte adhesion and expression of α3ß1 integrin, and increased apoptosis. Moreover, HBx-mediated downregulation of α3ß1 integrin expression is sufficient to reduce podocyte adhesion. HBx-induced apoptosis of podocytes may contribute to HBV-GN.

Hepatitis B Virus X Protein Modulates Apoptosis in NRK-52E Cells and Activates Fas/FasL Through the MLK3-MKK7-JNK3 Signaling Pathway.

BACKGROUND/AIMS: The hepatitis B virus X protein (HBx) contributes to HBV-induced injury of renal tubular cells and induces apoptosis via Fas/FasL up-regulation. However, the mechanism of Fas/FasL activation is unknown. Recent studies indicated that HBx induction of apoptosis in hepatic cells depends on activating the MLK3-MKK7-JNKs signaling module, which then up-regulates FasL expression. In this study, we used NRK-52E cells transfected an HBx expression vector to examine the role of the MLK3-MKK7-JNKs signaling pathway on HBx-induced renal tubular cell injury. METHODS: NRK-52E cells were transfected with pc-DNA3.1(+)-HBx to establish an HBx over-expression model, and with pc-DNA3.1(+)-HBx and pSilencer3.1-shHBx to establish an HBx low expression model. One control group was not transfected and another control group was transfected with an empty plasmid. Cell proliferation was determined by the formazan dye method (Cell Counting Kit-8) and apoptosis was measured by flow cytometry and fluorescence microscopy. Western blotting was used to measure the expression of Fas, FasL, and MLK3-MKK7-JNKs signaling pathway-related proteins. The activity of caspase-8 was measured by spectrophotometry. RESULTS: Transfection of NRK-52E cells with pc-DNA3.1(+)-HBx inhibited cell proliferation and increased apoptosis and caspase-8 activity. The expression of Fas, FasL, and MLK3-MKK7-JNKs signaling pathway-related proteins were also greater in the pc-DNA3.1(+)-HBx group, but lower in RNAi group. Furthermore, the activity of MLK3-MKK7-JNKs signaling pathway, expression of Fas/FasL, and apoptosis were significantly lower in the pc-DNA3.1(+)-HBx group when treated with K252a, a known inhibitor of MLK3. CONCLUSIONS: Our results show that HBx induces apoptosis in NRK-52E cells and activates Fas/FasL via the MLK3-MKK7-JNK3-c-Jun signaling pathway.

C-terminal sequence of amyloid-resistant type F apolipoprotein A-II inhibits amyloid fibril formation of apolipoprotein A-II in mice.

In murine senile amyloidosis, misfolded serum apolipoprotein (apo) A-II deposits as amyloid fibrils (AApoAII) in a process associated with aging. Mouse strains carrying type C apoA-II (APOA2C) protein exhibit a high incidence of severe systemic amyloidosis. Previously, we showed that N- and C-terminal sequences of apoA-II protein are critical for polymerization into amyloid fibrils in vitro. Here, we demonstrate that congenic mouse strains carrying type F apoA-II (APOA2F) protein, which contains four amino acid substitutions in the amyloidogenic regions of APOA2C, were absolutely resistant to amyloidosis, even after induction of amyloidosis by injection of AApoAII. In vitro fibril formation tests showed that N- and C-terminal APOA2F peptides did not polymerize into amyloid fibrils. Moreover, a C-terminal APOA2F peptide was a strong inhibitor of nucleation and extension of amyloid fibrils during polymerization. Importantly, after the induction of amyloidosis, we succeeded in suppressing amyloid deposition in senile amyloidosis-susceptible mice by treatment with the C-terminal APOA2F peptide. We suggest that the C-terminal APOA2F peptide might inhibit further extension of amyloid fibrils by blocking the active ends of nuclei (seeds). We present a previously unidentified model system for investigating inhibitory mechanisms against amyloidosis in vivo and in vitro and believe that this system will be useful for the development of novel therapies.

HSF1 Relieves Amyloid-ß-Induced Cardiomyocytes Apoptosis.

Accumulation of amyloid-ß in organs results in a series of diseases. Heat shock transcription factor 1 (HSF1) is the master regulator of genes encoding molecular chaperones and attenuates apoptosis induced by multiple factors. However, the role of HSF1 on amyloid-ß-induced apoptosis is still unknown. The present study was aimed to explore the function of HSF1 in amyloid-ß-induced cardiomyocytes apoptosis. TUNEL assay and flow cytometry analysis were used to detect cell apoptosis. Phalloidin staining was used to detect cytoskeleton injury. Changes in expression levels of proteins involved in apoptosis and endoplasmic reticulum stress were measured by Western blot. In our study, amyloid-ß was found to promote apoptosis, impair cytoskeleton, and induce endoplasmic reticulum stress in isolated cardiomyocytes. However, these damaging effects of amyloid-ß can be relieved by over-expression of HSF1, and the protective role of HSF1 might be associated with the regulation of HSPs expressions. Results of our study suggest that over-expression of HSF1 might become a promising gene therapeutic for the treatment of heart diseases associated with amyloid-ß accumulation.

The toxicity mechanisms of action of Aß25-35 in isolated rat cardiac myocytes.

ß-Amyloid (Aß) is deposited in neurons and vascular cells of the brain and is characterized as a pathologic feature of Alzheimer's disease (AD). Recently studies have reported that there is an association between cardiovascular risk factors and AD, however the mechanism of this association is still uncertain. In this study we observed Aß had an effect on cardiovascular cells. We represent as a major discovery that Aß25-35 had toxicity on isolated rat cardiac myocytes by impacting the cytoskeleton assembly and causing ER stress, ultimately contributing to the apoptosis of the myocytes. Importantly, the activation of ER stress and subsequent cellular dysfunction and apoptosis by Aß25-35 was regulated by the MAPK pathway, which could be prevented by inhibition of p38 via pharmacological inhibitors. It was noteworthy that Aß25-35 played a critical role in cardiac myocytes, suggesting that Alzheimer's disease (AD) had a relation with the heart and understanding of these associations in future will help search for effective treatment strategies.

Losartan attenuates renal interstitial fibrosis and tubular cell apoptosis in a rat model of obstructive nephropathy.

Ureteral obstruction leads to renal injury and progresses to irreversible renal fibrosis, with tubular cell atrophy and apoptosis. There is conflicting evidence concerning whether losartan (an angiotensin II type I receptor antagonist) mitigates renal interstitial fibrosis and renal tubular epithelial cell apoptosis following unilateral ureteral obstruction (UUO) in animal models. The aim of this study was to investigate the effect and mechanism of losartan on renal tubular cell apoptosis and renal fibrosis in a rat model of UUO. The rats were subjected to UUO by ureteral ligation and were treated with dimethyl sulfoxide (control) or losartan. The controls underwent sham surgery. The renal tissues were collected 3, 5, 7 and 14 days after surgery for measurement of various indicators of renal fibrosis. UUO increased the expression levels of α­smooth muscle actin and collagen I, and the extent of renal tubular fibrosis and apoptosis in a time­dependent manner. Losartan treatment partially attenuated these responses. Progression of renal interstitial fibrosis was accompanied by phosphorylation of signal transducer and activator of transcription 3 (STAT3) and altered the expression levels of two apoptosis­related proteins (Bax and Bcl2). Losartan treatment also partially attenuated these responses. The results indicated that losartan attenuated renal fibrosis and renal tubular cell apoptosis in a rat model of UUO. This effect appeared to be mediated by partial blockage of STAT3 phosphorylation.

Effects of mesenchymal stem cells transplanted at different time points in a rat remnant kidney model.

AIMS: The optimal time for mesenchymal stem cell (MSCs) transplantation remains an unresolved issue. We compared the effects of MSCs on a rat remnant kidney model. METHODS: Male Sprague-Dawley rats were randomly divided and treated with a corresponding reagent at 4, 8, 12 and 16 weeks, respectively. A remnant kidney model was established and MSCs were injected into rats. The migration of MSCs was then assessed by using cell-tracking experiments. Renal function and histological analyses were performed 4 weeks after MSC transplantation. Immunohistochemistry, Western blotting and real-time polymerase chain reaction were used to detect the TGF-ß1 and α-SMA levels. RESULTS: Four weeks after MSC injection, MSCs were found to migrate to the injured kidney. Significant histological damage improvement was observed after the treatment of MSCs at 4 and 8 weeks. The functional benefits of MSC treatment were observed in the 5/6 nephrectomy (Nx) + MSC group and the benefits were significantly higher at 4 and 8 weeks than at other time points (p < 0.05). Meanwhile, serum creatinine and urea levels as well as glomerular sclerosis and tubulointerstitial injury indexes were decreased at 4 and 8 weeks. Compared with the 5/6 Nx + PBS group, TGF-ß1 and α-SMA levels were decreased in the 5/6 Nx + MSC group. CONCLUSION: These data can be used to optimize the MSC transplantation time point as a therapeutic modality.

HBx inhibits proliferation and induces apoptosis via Fas/FasL upregulation in rat renal tubular epithelial cells.

BACKGROUND: The hepatitis B virus X protein (HBx) regulates numerous signaling pathways, including those that modulate apoptosis. However, previous research has indicated different effect of HBx on apoptosis, possibly because of differences in the experimental conditions and cell types. The purpose of this study was to investigate the mechanism of HBx-induced apoptosis of rat renal tubular epithelial (NRK-52E) cells. METHODS: An HBx expression vector (pc-DNA3.1(+)-HBx) was used to transfect NRK-52E cells to establish an HBx overexpression model. One control group was not transfected and the other control group was transfected with plasmid lacking the HBx-encoding insert. Cell proliferation was measured using the MTT assay, and the rate of apoptosis was determined by flow cytometry and fluorescence microscopy. The expressions of Fas, FasL, Bcl-2 and Bax were determined by Western blotting and reverse transcription polymerase chain reaction, and the activity of caspase-8 was measured by spectrophotometry.
 RESULTS: Transfection of NRK-52E cells with pc-DNA3.1(+)-HBx led to inhibition of proliferation and increased apoptosis relative to the controls. Transfected cells had increased mRNA and protein expression of Fas, FasL and Bax and decreased mRNA and protein expression of Bcl-2 relative to the controls. In addition, transfected cells had increased caspase-8 activity relative to the controls. CONCLUSIONS: Our results suggest that HBx induces apoptosis in NRK-52E cells, at least in part through activation of the Fas/FasL pathway. The activation of caspase-8 appears to mediate the induction of apoptosis.