GEN1 as a risk factor for human congenital anomalies of the kidney and urinary tract.

BACKGROUND: Congenital anomalies of the kidney and urinary tract (CAKUT) are prevalent birth defects. Although pathogenic CAKUT genes are known, they are insufficient to reveal the causes for all patients. Our previous studies indicated GEN1 as a pathogenic gene of CAKUT in mice, and this study further investigated the correlation between GEN1 and human CAKUT. METHODS: In this study, DNA from 910 individuals with CAKUT was collected; 26 GEN1 rare variants were identified, and two GEN1 (missense) variants in a non-CAKUT group were found. Mainly due to the stability results of the predicted mutant on the website, in vitro, 10 variants (eight CAKUT, two non-CAKUT) were selected to verify mutant protein stability. In addition, mainly based on the division of the mutation site located in the functional region of the GEN1 protein, 8 variants (six CAKUT, two non-CAKUT) were selected to verify enzymatic hydrolysis, and the splice variant GEN1 (c.1071 + 3(IVS10) A > G) was selected to verify shear ability. Based on the results of in vitro experiments and higher frequency, three sites with the most significant functional change were selected to build mouse models. RESULTS: Protein stability changed in six variants in the CAKUT group. Based on electrophoretic mobility shift assay of eight variants (six CAKUT, two non-CAKUT), the enzymatic hydrolysis and DNA-binding abilities of mutant proteins were impaired in the CAKUT group. The most serious functional damage was observed in the Gen1 variant that produced a truncated protein. A mini-gene splicing assay showed that the variant GEN1 (c.1071 + 3(IVS10) A > G) in the CAKUT group significantly affected splicing function. An abnormal exon10 was detected in the mini-gene splicing assay. Point-mutant mouse strains were constructed (Gen1: c.1068 + 3 A > G, p.R400X, and p.T105R) based on the variant frequency in the CAKUT group and functional impairment in vitro study and CAKUT phenotypes were replicated in each. CONCLUSION: Overall, our findings indicated GEN1 as a risk factor for human CAKUT.

Floating-gate memristor based on a MoS2/h-BN/AuNPs mixed-dimensional heterostructure.

Memristors have recently received substantial attention because of its promising and unique application scenes emerging in neuromorphic computing which can achieve gains in computation speed by mimicking the topology of brains in electronic circuits. Traditional memristors made of bulk MoO3 and HfO2, etc. suffer from low switching ratio, short durability and poor stability. In this work, a floating-gate memristor is developed based on a mixed-dimensional heterostructure which is comprised of two-dimensional (2D) molybdenum disulfide (MoS2) and 0-dimensional (0D) Au nanoparticles (AuNPs) separated by an insulating hexagonal boron nitride (h-BN) layer, hereafter, MoS2/h-BN/AuNPs. We find that under the modulation of back-gate voltages, the MoS2/h-BN/AuNPs device operates reliably between a high resistance state (HRS) and a low resistance state (LRS) and that it shows multiple stable LRS states, demonstrating high potential of our memristor in application of multibit storage. The modulation effect can be attributed to the electron quantum tunneling between the AuNPs charge-trapping layer and MoS2 channel. Our memristor exhibits excellent durability and stability: the HRS and LRS remain more than 104 s without obvious degradation and the on/off ratio retains > 104 after more than 3000 switching cycles. We also demonstrate frequency-dependent memory properties upon electrical and optical pulse stimuli.

The value of bioimpedance analysis in the assessment of hydration and nutritional status in children on chronic peritoneal dialysis.

Bioimpedance analysis (BIA)-body composition monitoring (BCM) has been used to evaluate the hydration and nutritional status of adults and children on dialysis. However, its clinical application still has challenges, so further exploration is valuable. We used BIA-BCM to evaluate the hydration and nutritional status of children undergoing chronic peritoneal dialysis from 1 July 2021 to 31 December 2022 in the Children's Hospital of Fudan University to explore the clinical value of this method. A total of 84 children on chronic peritoneal dialysis (PD) were included. In the PD group, 16 (19.05%) and 31 (36.90%) had mild and severe overhydration (OH), respectively; 41.27% (26/63) had a low lean tissue index (LTI). In the PD group, patients with relative OH (Re-OH) > 5.6% had significantly higher systolic blood pressure (SBP) and SBP z score (SBPz). Patients with LTI > 12% had significantly higher body mass index (BMI) and BMI z score (BMIz). Canonical correlation analysis indicated a linear relationship (ρ = 0.708) between BIA-BCM hydration and the clinical hydration indicator and a linear relationship (ρ = 0.995) between the BIA-BCM nutritional indicator and the clinical nutritional indicator. A total of 56% of children on chronic peritoneal dialysis had OH, and 41% had a low LTI. In PD patients, SBP and SBPz were correlated with BIA-BCM Re-OH, and BMI and BMIz were correlated with BIA-BCM LTI. BIA-BCM indicators have good clinical value in evaluating hydration and nutrition.

Clinical characteristics of patients with prenatal hydronephrosis in early postnatal period: a single center retrospective study.

BACKGROUND: The study aims to investigate the clinical characteristics of early postnatal period in children with prenatal hydronephrosis (HN) in our single center for 8 years. STUDY DESIGN: The clinical data of 1137 children with prenatal HN from 2012 to 2020 were retrospectively analyzed in our center. Variables of our study mainly included different malformations and urinary tract dilation (UTD) classification, and main outcomes were recurrent hospitalization, urinary tract infection (UTI), jaundice, and surgery. RESULTS: Among the 1137 children with prenatal HN in our center, 188 cases (16.5%) were followed-up in early postnatal period, and 110 cases (58.5%) were found malformations. The incidence of recurrent hospitalization (29.8%) and UTI (72.5%) were higher in malformation, but the incidence of jaundice (46.2%) was higher in non-malformation(P < 0.001). Furthermore, UTI and jaundice were higher in vesicoureteral reflux (VUR) than those in uretero-pelvic junction obstruction (UPJO) (P < 0.05). Meanwhile, Children with UTD P2 and UTD P3 were prone to recurrent UTI, but UTD P0 was prone to jaundice (P < 0.001). In addition, 30 cases (16.0%) of surgery were all with malformations, and the surgical rates of UTD P2 and UTD P3 were higher than those of UTD P0 and UTD P1 (P < 0.001). Lastly, we concluded that the first follow-up should be less than 7 days, the first assessment should be 2 months, and the follow up should be at least once every 3 months. CONCLUSION: Children with prenatal HN have been found many malformations in early postnatal period, and with high-grade UTD were more prone to recurrent UTI, even to surgery. So, prenatal HN with malformations and high-grade UTD should be followed up in early postnatal period regularly.

PPARα agonist exerts protective effects in podocyte injury via inhibition of the ANGPTL3 pathway.

Peroxisome proliferator-activated receptor α (PPARα) activation has been reported to exert protective effects on podocytes, whereas angiopoietin-like 3 (ANGPTL3) has been shown to exert significant pathogenic effects on these cells. This study aimed to investigate the link between the protective effects of PPARα activation and the pathogenic effects of ANGPTL3 in podocytes. Both PPARα and ANGPTL3 were expressed in cultured podocytes. PPARα mRNA and protein levels decreased whereas ANGPTL3 mRNA and protein levels increased in a time-dependent manner in podocytes treated with puromycin aminonucleoside (PAN). Gemfibrozil, a pharmacological agonist of PPARα, increased PPARα levels and activity in podocytes. The drug also decreased ANGPTL3 levels by potentially weakening ANGPTL3 promoter activity in both normal and PAN-treated podocytes. Furthermore, gemfibrozil significantly decreased PAN-induced apoptosis and F-actin rearrangement. Primary podocytes from Angptl3-knockout mice were cultured. There was no significant difference between Angptl3-/- podocytes treated with or without gemfibrozil in the lamellipodia numbers after PAN treatment. The results suggested that the protective effects of gemfibrozil on podocytes were not exerted following knockout of the Angptl3 gene. This study identified a novel mechanism of the PPARα agonist gemfibrozil that exerts its protective effects by inhibiting PAN-induced apoptosis and cytoskeleton rearrangements through inhibition of ANGPTL3 expression.

Reduction in peritonitis rates: 18-year results from the most active pediatric peritoneal dialysis center in China.

BACKGROUND: Most of the available epidemiological data on peritonitis have been derived from developed countries. Limited data from China have been reported. METHODS: An 18-year (2001-2018) peritoneal dialysis (PD) program at the Children's Hospital of Fudan University was described, and data on peritonitis were retrospectively analyzed. RESULTS: Since 2001, a program with a comprehensive PD care bundle has been developed, and 283 patients (53.7% male, median age 9.3 years) were enrolled between 2001 and 2018. Among these patients, 117 peritonitis episodes occurred in 68 (24.0%) patients over 4896 patient-months. The peritonitis rate decreased 20-fold from 2.2 episodes per patient-year in 2003 to 0.11 episodes in 2018. The culture-negative rate decreased from 68.7% during 2001-2006 to 18.5% during 2013-2018, and the proportion of gram-negative and fungal infections increased significantly from 6.6 to 33.8% and 0 to 9.2%, respectively (p < 0.001). Short stature as height ≤ - 2 SD (OR 2.35, 95% CI 1.30-4.24, p = 0.005) and PD duration ≥ 1 year (OR 3.38, 95% CI 1.76-6.49, p < 0.001) were independently associated with a higher risk of developing peritonitis. Of the 117 peritonitis episodes, 9.4% required permanent removal of the catheter, among which half were fungal infections. Patients with peritonitis had a higher risk for PD technique failure (p = 0.006), but there was no difference in estimated patient survival rates and no patient death due to peritonitis. CONCLUSIONS: With the successful development of the PD program and care bundles per the International Society of Pediatric Dialysis (ISPD) guidelines, peritonitis rates have been tremendously reduced in the most active pediatric PD center in China. Growth deficits and a long PD duration were risk factors for developing peritonitis, requiring further close monitoring for a better outcome. A higher resolution version of the Graphical abstract is available as Supplementary information.

Comparative proteomic analysis of children FSGS FFPE tissues.

BACKGROUND: In children, focal segmental glomerulosclerosis (FSGS) is the main cause of steroid resistant nephrotic syndrome (SRNS). To identify specific candidates and the mechanism of steroid resistance, we examined the formalin-fixed paraffin embedded (FFPE) renal tissue protein profiles via liquid chromatography tandem mass spectrometry (LC-MS/MS). METHODS: Renal biopsies from seven steroid-sensitive (SS) and eleven steroid-resistant (SR) children FSGS patients were obtained. We examined the formalin-fixed paraffin embedded (FFPE) renal tissue protein profiles via liquid chromatography tandem mass spectrometry (LC-MS/MS). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and Gene Ontology (GO) analysis, as well as the construction of protein-protein interaction (PPI) network were performed. Two proteins were further valiadated by immunohistochemistry staining in FSGS patients and mice models. RESULTS: In total, we quantified more than 4000 proteins, of which 325 were found to be differentially expressed proteins (DEPs) between the SS and SR group (foldchange ≥2, P<0.05). The results of GO revealed that the most significant up-regulated proteins were primarily related to protein transportation, regulation of the complement activation process and cytolysis. Moreover, clustering analysis showed differences in the pathways (lysosome, terminal pathway of complement) between the two groups. Among these potential candidates, validation analyses for LAMP1 and ACSL4 were conducted. LAMP1 was observed to have a higher expression in glomerulus, while ACSL4 was expressed more in tubular epithelial cells. CONCLUSIONS: In this study, the potential mechanism and candidates related to steroid resistance in children FSGS patients were identified. It could be helpful in identifying potential therapeutic targets and predicting outcomes with these proteomic changes for children FSGS patients.

A Therapeutic Play Program for Children Undergoing Kidney Biopsy With Local Anesthesia: Construction and Feasibility Evaluation.

PURPOSE: To construct a therapeutic play program for children undergoing preparation for kidney biopsy under local anesthesia and explore the feasibility of the program from stakeholders' perspectives. DESIGN: The program was constructed by a multidisciplinary team and the feasibility and acceptability of the program were explored by a descriptive qualitative study. METHODS: Based on Lazarus & Folkman's stress-coping model and Piaget's theory of play, and using on-site participatory field observation, a multidisciplinary team constructed a therapeutic play program for children undergoing kidney biopsy under local anesthesia. The feasibility and acceptability of the program were evaluated by interviewing children, their caregivers, and physicians. FINDINGS: The main tools constructed for the intervention were a 15-page picture book titled Kidney Biopsy Treasure Hunt and a homemade kidney biopsy play package. The therapeutic play intervention for kidney biopsy under local anesthesia was led by nurses and followed the steps of kidney biopsy, using the picture book, and group play simulation. Through informed in-depth interviews with 10 children and their caregivers, we showed that the therapeutic play program materials were accessible, clinically feasible, and necessary for kidney biopsy under local anesthesia in children. The children and their caregivers had high acceptance of the content of the picture book, the format of the play, and high satisfaction with the overall program. CONCLUSIONS: The therapeutic play program we constructed for children undergoing kidney biopsy with local anesthesia was simple, feasible, and well accepted in the clinical setting.

Diagnostic and clinical utility of genetic testing in children with kidney failure.

BACKGROUND: Genetic kidney disease is well established as an important cause of pediatric kidney failure, and genetic testing might increase diagnostic accuracy, but evidence is limited. This study was conducted to determine the diagnostic yield and clinical impact of genetic testing for children with kidney failure. METHODS: Patients who were diagnosed with kidney failure before 19 years of age at Children's Hospital of Fudan University from 2009 to 2018 and received next-generation sequencing (NGS) were enrolled. The results for likely pathogenic variants in genes known to cause chronic kidney disease (CKD) were analyzed. RESULTS: A molecular diagnosis was identified in 39.9% (75/188) of children with kidney failure. Specific subtype of clinical category was discerned in 54 (72.0%) patients, kidney disease was reclassified in 7 (9.3%) patients, the unknown etiology of 5 (6.7%) patients was molecularly diagnosed, and the clinical diagnoses of the other 9 (12.0%) patients were confirmed. In addition, genetic diagnosis was considered to have contributed to clinical management, including negating the need for kidney biopsy (26/75, 34.7%), avoiding immunosuppressive therapy (24/75, 32.0%), changing surveillance (48/75, 64.0%), guiding specific treatment (21/75, 28.0%), and guiding peri-transplant management and options for kidney transplantation (12/75, 16.0%). Furthermore, cascade testing was subsequently offered to 34.7% (26/75) of families. CONCLUSIONS: Genetic testing identified a molecular diagnosis in nearly 40% of children with kidney failure. Our results confirm that in children with kidney failure, genetic testing can not only establish a specific molecular diagnosis, but has a significant impact on clinical management.

Pediatric kidney transplantation in China: an analysis from the IPNA Global Kidney Replacement Therapy Registry.

BACKGROUND: The International Pediatric Nephrology Association (IPNA) Global Kidney Replacement Therapy (KRT) Registry was established to evaluate the incidence and outcomes of kidney replacement therapy (dialysis and transplantation) provided to children worldwide. Analysis of registry data for separate regions is feasible. METHODS: Three centers located in Shanghai, Guangzhou, and Zhengzhou, which have the greatest number of pediatric kidney transplantation cases in China, participated in this analysis of transplant data. Data were registered by each center for patients under the age of 19 years who received a single-organ kidney transplant for the first time between 2011 and 2018. RESULTS: In total, 415 patients (59.8% male) aged 1.4-18.7 (median 12.1) years were followed for 0.3-97.1 (median 27.7) months. The number of kidney transplants increased from a total of 129 during 2011-2014 to 286 cases during 2015-2018. 85.8% of patients received the transplanted kidney from a pediatric (age < 19 years) donor, and deceased donors accounted for 94% of all donors. 8.0% of grafts were lost. One and 5-year patient survival rates were 97.6% and 95.5%, respectively. The major cause of death was infection (7/14). Similar graft and patient survival rates were observed for organs from pediatric and adult donors in 6-11 and 12-18 year recipient age groups, whereas recipients < 6 years showed inferior patient and graft survival. CONCLUSIONS: Pediatric kidney transplantation shows favorable short-term and medium-term outcomes in China. Our experience supports use of pediatric donors in pediatric kidney transplantation, but attention directed to the outcome of recipients aged under 6 is necessary. Graphical abstract.

Intrauterine low-protein diet aggravates developmental abnormalities of the urinary system via the Akt/Creb3 pathway in Robo2 mutant mice.

The offspring of Robo2 mutant mice usually present with variable phenotypes of congenital anomalies of the kidney and urinary tract (CAKUT). An intrauterine low-protein diet can also cause CAKUT in offspring, dominated by the duplicated collecting system phenotype. A single genetic or environment factor can only partially explain the pathogenesis of CAKUT. The present study aimed to establish an intrauterine low-protein diet roundabout 2 (Robo2) mutant mouse model and found that the intrauterine low-protein diet led to significantly increased CAKUT phenotypes in Robo2PB/+ mice offspring, dominant by a duplicated collecting system. At the same time, more ectopic and lower located ureteric buds (UBs) were observed in the intrauterine low-protein diet-fed Robo2 mutant mouse model, and the number of UB branches was reduced in the serum-free culture. During UB protrusion, intrauterine low-protein diet reduced the expression of Slit2/Robo2 in Robo2 mutant mice and affected the expression of glial cell-derived neurotrophic factor/Ret, which is a key molecule for metanephric development, with increasing phospho-Akt and phospho-cAMP responsive element-binding protein 3 activity and a reduction of apoptotic cells in embryonic day 11.5 UB tissues. The mechanism by which an intrauterine low-protein diet aggravates CAKUT in Robo2 mutant mice may be related to the disruption of Akt/cAMP responsive element-binding protein 3 signaling and a reduction in apoptosis in UB tissue.

IPDN-China promotes the development of pediatric dialysis in China.

BACKGROUND: In mainland China, dialysis for children with end-stage renal disease (ESRD) was not introduced until the 1980s. To describe the development of pediatric dialysis in different regions of China, a national pediatric dialysis network, namely, International Pediatric Dialysis Network-China (IPDN-China) ( www.pedpd.org.cn ), was launched in 2012. METHODS: Original and updated information from the renal centers registered with the IPDN-China was collected between 2012 and 2016 from two sources, namely, the registry and the survey, and demographic features were analyzed. RESULTS: Due to promotion by the IPDN-China, the number of registered renal centers increased from 12 to 39 between 2012 and 2016, with a significant increase in the coverage of the Chinese administrative divisions (from 26.5 to 67.6%) (p < 0.01); and the coverage of the pediatric (0~14 years old) population increased to nearly 90% in 2016. The distribution of renal centers indicated that East China had the highest average number of registered centers per million population (pmp) 0~14-year-old age group. Seventeen relatively large dialysis centers were distributed across 14 divisions. Various modalities of renal replacement therapy (RRT) were available in most centers. The IPDN-China has promoted collaborations between dieticians, psychologists, and social workers on dialysis teams to provide better service to children with ESRD and their families. The proportion of centers with all three types of paramedic support (i.e., dieticians, psychologists, and social workers) as well as the proportion of centers with a partial paramedic team significantly increased between 2012 (25.0%) and 2016 (69.2%) (p < 0.05). In terms of the point prevalent cases of patients (aged < 18 years), data from the survey of 39 registered centers revealed that the number of children with ESRD who were on RRT was 578 (49% received a kidney transplant) at the end of 2016, which was more than that reported in previous surveys. Data from the registry showed that 349 dialysis patients had been enrolled as of the end of 2016. The median age at RRT start was 9.5 years, and the leading cause of ESRD was congenital abnormalities of the kidney and urinary tract (CAKUT). CONCLUSIONS: The IPDN-China has helped to promote the development of pediatric dialysis for ESRD in China by improving the organization of care for dialysis patients and increasing the availability and the quality of RRT for patients who need it. To improve knowledge about the epidemiology and outcomes of pediatric RRT around the country, a sustained effort needs to be made by the IPDN-China to increase the enrollment of dialysis patients and increase the number of registered centers in the future.

Money matters: a multicenter cross-sectional study of depressive symptoms among the caregivers of children on peritoneal dialysis in Mainland China.

BACKGROUND: The caregivers of children on peritoneal dialysis face heavy care burdens and may have a high risk of depression. This study aimed to describe the prevalence and severity of depression and identify its related demographic and socioeconomic factors in the caregivers of children on peritoneal dialysis in China. METHODS: A multicenter cross-sectional study was conducted in four pediatric dialysis centers in four tertiary children's hospitals in mainland China. Primary caregivers of children with end-stage kidney disease and currently on peritoneal dialysis were screened and recruited from December 2018 to July 2019. A self-developed questionnaire and the Self-Rating Depression Scale (SDS) were administered to the participants by a trained nurse in each center. The chi-square test or Fisher's exact test, one-way ANOVA, and the Mann-Whitney U test were used to compare the prevalence of depressive symptoms by demographic features. A multivariate logistic regression analysis was used to identify factors related to depressive symptoms in caregivers of children on peritoneal dialysis. RESULTS: One hundred twenty-one caregivers were included in the data analysis. The mean age of the caregivers was 40.1 ± 8.1 years. More than 75% of the participants were female, married, and unemployed. The overall prevalence of depressive symptoms was 59%. In total, 46 (38%), 20 (17%) and 5 (4%) caregivers reported mild, moderate, and severe depressive symptoms, respectively. In the univariate analysis, caregivers with an average household income per month under 4000 RMB and caregivers of children undergoing laparoscopic surgery had a higher prevalence of depressive symptoms. Characteristics such as treatment center, duration on PD, PD modalities, and history of peritonitis episodes showed no difference in terms of the prevalence of depressive symptoms. The multivariate logistic regression analysis demonstrated that an average household income per month under 4000 RMB was the associated factor for caregivers' depressive symptoms. CONCLUSIONS: The caregivers of children on peritoneal dialysis in mainland China were socially vulnerable and experienced depression. Those who had a higher average household income were less vulnerable to depression.

Intrauterine low-protein diet disturbs metanephric gene expression and induces urinary tract developmental abnormalities in mice.

Intrauterine low-protein diet can affect kidney development and hence final nephron number. In this study, we reported that intrauterine low-protein diet can cause congenital anomalies of the kidney and urinary tract (CAKUT) phenotypes, which was dominated by the duplicated collecting system phenotype. At the same time, ectopic ureteric buds were increased under intrauterine low-protein diet and the number of UB branches was reduced in the serum-free culture. Intrauterine low-protein diet can change metanephric gene expression. Slit2/Robo2 and Spry1 expression levels were decreased, Ret expression was increased, and downstream p-Akt activity enhanced with apoptosis abnormal in ureteric bud tissue, which may be the mechanisms that intrauterine low-protein diet causes increased incidence of CAKUT in offspring. Thus, we showed correlation between intrauterine low-protein diet and CAKUT in offspring.

Anti-proteinuria effect of antibody against ANGPTL3 coil-coiled domain on adriamycin-induced nephropathy in mice.

Proteinuria is an important marker and is closely related to the progressive decline of renal function. Our previous research showed that angiopoietin-like-3 (ANGPTL3) plays a crucial role in proteinuria. In this study, we prepared an antibody against ANGPTL3 coil-coiled domain (ANGPTL3-CCD) and investigated the protective effect of anti-ANGPTL3-CCD antibody in mice with adriamycin-induced nephropathy. Nephropathy was established by adriamycin injection at a dose of 25 mg per kg in 8-12 week-old male mice in the ADR group. Blockade of ANGPTL3 by anti-ANGPTL3-CCD antibody (20 mg per kg) was performed every three days nine times after adriamycin injection in the ADR plus anti-angptl3-antibody group. The anti-ANGPTL3-CCD antibody can specifically recognize ANGPTL3. After anti-ANGPTL3-CCD antibody intervention, the urinary protein level in the ADR plus anti-angptl3-antibody group was significantly lower than that in the ADR group. Serum albumin was higher and triglyceride and total cholesterol were lower in the ADR plus anti-angptl3-antibody group than in the ADR group. The levels of serum creatinine did not significantly differ among the groups. Focal sclerotic glomeruli and podocyte foot processes extensive fusion were found in the renal tissue of the ADR group, whereas no sclerotic glomeruli and only partial fusion were found in the ADR plus anti-angptl3-antibody group. This study demonstrated that the anti-ANGPTL3-CCD antibody ameliorated proteinuria and podocyte dysfunction in adriamycin-induced nephropathy in mice.

Gene mutation and clinical analysis of nephronophthisis diagnosed using whole exome sequencing: Experience from China
.

OBJECTIVE: Nephronophthisis (NPH) is an autosomal recessive cystic kidney disease. Its onset is obscure, and its early clinical manifestations and pathological changes lack specificity, which makes clinical diagnosis difficult. At present, as many as 90 genetic alterations can result in NPH, which exhibits significant genetic heterogeneity. Therefore, high-throughput sequencing technology provides an effective method to identify and characterize novel NPH pathogenic genes when compared to Sanger sequencing. This study summarizes the gene mutations and clinical data of whole exome sequencing, which was used to diagnose 5 NPH patients to improve the understanding of the causative genes and clinical phenotypes of NPH. MATERIALS AND METHODS: The clinical manifestations, laboratory examination indexes, and imaging data of 5 patients of NPH were reported. Whole exome sequencing was performed in 5 children, and the causative genes and mutation sites were analyzed by bioinformatics and genetics. The mutation sites were verified in children and their parents using Sanger direct sequencing. RESULTS: Among the 5 patients (3 male and 2 female), 2 patients had infantile NPH, and 3 patients had juvenile NPH. The 2 infantile NPH patients were characterized by the onset of liver dysfunction accompanied by hypertension and left ventricular change, and the renal function progressed to end-stage renal disease (ESRD) after 7 months and 9 months, respectively. The 2 cases of infantile NPH had NPHP3 mutations, with one carrying compound heterozygous mutations (c.1358A>G, c.2369A>G) and the other simultaneously carrying a c.1174C>T IVS26-3A>G cleavage site mutation from the father and a nonsense mutation (p.392R>X, 939) from the mother. The 2 juvenile NPH children had entered ESRD at the onset of the disease, including 1 patient with Joubert syndrome. The 2 patients with juvenile NPH had frameshift mutations (c.1583 to 1596: deletion) and homozygous point mutations (7 c.640G>T) of the NPHP1 gene. In addition, another patient with frequent urination and nocturia resulting in stage CKD3 renal function had a complex heterozygous mutation of the NPHP2 gene (c.2686G>A, c.1943A>G). The urine A1MU/creatinine and urinary transferrin increased in all 5 patients without hematuria. CONCLUSION: Whole exome sequencing identified the causative genes of NPH in 5 children. In NPH children with NPHP3 gene mutations, renal functional damage was characterized by early onset and rapid progression to ESRD, often accompanied by liver dysfunction and hypertension.

Angiopoietin-like-3 knockout protects against glomerulosclerosis in murine adriamycin-induced nephropathy by attenuating podocyte loss.

BACKGROUND: Angiopoietin-like-3 (Angptl3) knockout is known for its protective effects on podocyte injury and proteinuria in the early stage of adriamycin (ADR) nephropathy. The current study re-evaluated the renoprotective effect of Angptl3 knockout in chronic ADR nephropathy and attempted to explore the mechanism underlying the effect associated with Angptl3 knockout in glomerulosclerosis. METHODS: B6; 129S5 mice were injected with ADR to induce nephropathy. Kidney structure and serum and urine parameters were observed during long-term follow-up. Cultured primary mouse podocytes were exposed to ADR and analyzed for the expression of some relative proteins. Podocyte loss was analyzed in both in vivo and in vitro experiments. RESULTS: Angptl3 knockout attenuated proteinuria and hypoproteinemia, protected renal structure and function, and improved the survival of mice over the whole process of ADR nephropathy. Furthermore, Angptl3 knockout reduced the numbers of the detached and apoptotic cells in the renal tissue and alleviated podocyte loss in mice with ADR chronic nephropathy, thereby, delaying the glomerulosclerosis formation. Additional results in vitro showed that Angptl3 knockout attenuated ADR-induced primary podocyte loss, including podocyte detachment and apoptosis. CONCLUSION: In addition to serving a renoprotective role in the early stage of ADR nephropathy, Angptl3 knockout contributed to disease amelioration throughout the ADR nephropathy process. Angptl3 knockout effectively delayed glomerulosclerosis formation by attenuating podocyte loss through rescuing podocytes from detachment and apoptosis. Angptl3 antagonists or inhibitors might have therapeutic potential in the occurrence and progression of nephropathy.

pH-mediated upregulation of AQP1 gene expression through the Spi-B transcription factor.

BACKGROUND: Bicarbonate-based peritoneal dialysis (PD) fluids enhance the migratory capacity and damage-repair ability of human peritoneal mesothelial cells by upregulating AQP1. However, little is known about the underlying molecular mechanisms. RESULTS: Here we used HEK-293T cells to investigate the effect of pH on AQP1 gene transcription levels. We found that AQP1 mRNA levels increases with pH. Transfection of HEK-293T cells with luciferase reporter vectors containing different regions of the AQP1 promoter identified an upstream region in the AQP1 gene between - 2200 and - 2300 bp as an enhancer required for pH-mediated regulation of AQP1 expression. Site-directed mutagenesis of this specific promoter region revealed a critical region between - 2257 and - 2251 bp, and gene knock-down experiments and ChIP assays suggested that the Spi-B transcription factor SPIB is involved in pH-mediated regulation of AQP1 expression. CONCLUSIONS: We identified an upstream region in the AQP1 gene and the transcription factor SPIB that are critically involved in pH-mediated regulation of AQP1 expression. These findings provide the basis for further studies on the pH- and buffer-dependent effects of PD fluids on peritoneal membrane integrity and function.

Gene mutation analysis in 12 Chinese children with congenital nephrotic syndrome.

BACKGROUND: Congenital nephrotic syndrome (CNS) is characterised by increased proteinuria, hypoproteinemia, and edema beginning in the first 3 months of life. Recently, molecular genetic studies have identified several genes involved in the pathogenesis of CNS. A systematic investigation of the genes for CNS in China has never been performed; therefore, we conducted a mutational analysis in 12 children with CNS,with the children coming from 10 provinces and autonomous regions in China. METHODS: Twelve children with CNS were enrolled from 2009 to 2016. A mutational analysis was performed in six children by Sanger sequencing in eight genes (NPHS1, NPHS2, PLCE1, WT1, LAMB2, LMXIB, COQ6 and COQ2) before 2014, and whole-exome sequencing was used from 2014 to 2016 in another six children. Significant variants that were detected by next generation sequencing were confirmed by conventional Sanger sequencing in the patients' families. RESULTS: Of the 12 children, eight patients had a compound heterozygous NPHS1 mutation, one patient had a de novo mutation in the WT1 gene, and another patient with extrarenal symptoms had a homozygous mutation in the COQ6 gene. No mutations were detected in genes NPHS2, PLCE1, LAMB2, LMXIB, and COQ2 in the 12 patients. CONCLUSIONS: This study demonstrates that the majority of CNS cases (67%, 8/12 patients) are caused by genetic defects, and the NPHS1 mutation is the most common cause of CNS in Chinese patients. A mutational analysis of NPHS1 should be recommended in Chinese patients with CNS in all exons of NPHS1 and in the intron-exon boundaries.

Clinical and genetic analysis of distal renal tubular acidosis in three Chinese children.

OBJECTIVE: Primary distal renal tubular acidosis (dRTA) is a rare genetic disease characterized by distal tubular dysfunction leading to metabolic acidosis and alkaline urine. Growth retardation is a major concern in these children. The disease is caused by defects in at least three genes (SLC4A1, ATP6V0A4, and ATP6V1B1) involved in urinary distal acidification. Several series of dRTA patients from different ethnic backgrounds have been genetically studied, but genetic studies regarding Chinese population is rare. Our aim was to investigate the clinical features and genetic basis of primary dRTA in Chinese children. METHODS: Three unrelated patients with dRTA participated in our study. Next-generation sequencing was performed, and the findings were validated using the Sanger sequencing method. RESULTS: All patients exhibited hyperchloraemic metabolic acidosis, abnormally high urine pH, hypokalemia, and nephrocalcinosis. Growth retardation was observed in all patients. During the follow-up (range 1-4 years), alkali replacement therapy corrected the systemic metabolic acidosis, and two patients demonstrated normal growth. rhGH therapy was administered to patient-3 at the age of 6 years, and his growth rate was significantly improved (growth velocity 9.6 cm/yr). In total, 5 mutations were identified in our cohort of three patients, and four mutations were novel. CONCLUSIONS: We report the clinical and molecular characteristics of dRTA patients from China. The four novel mutations detected in our study extend the spectrum of gene mutations associated with primary dRTA. Furthermore, our study confirms the effect of early treatment in improving growth for dRTA patient and provides insight into the effects of rhGH on dRTA patients who were diagnosed late and exhibiting a persistent growth delay despite appropriate therapy.