Identification of renal cyst cells of type I Nephronophthisis by single-nucleus RNA sequencing.

Background: Nephronophthisis (NPH) is the most common genetic cause of end-stage renal disease (ESRD) in childhood, and NPHP1 is the major pathogenic gene. Cyst formation at the corticomedullary junction is a pathological feature of NPH, but the mechanism underlying cystogenesis is not well understood. The isolation and identification of cystic cell subpopulation could help to identify their origins and provide vital clues to the mechanisms underlying cystogenesis in NPH. Methods: Single-nucleus RNA sequencing (snRNA-seq) was performed to produce an atlas of NPHP1 renal cells. Kidney samples were collected from WT (Nphp1 +/+) mice and NPHP1 (Nphp1 del2-20/del2-20) model mice. Results: A comprehensive atlas of the renal cellular landscape in NPHP1 was generated, consisting of 14 basic renal cell types as well as a subpopulation of DCT cells that was overrepresented in NPHP1 kidneys compared to WT kidneys. GO analysis revealed significant downregulation of genes associated with tubular development and kidney morphogenesis in this subpopulation. Furthermore, the reconstruction of differentiation trajectories of individual cells within this subpopulation confirmed that a specific group of cells in NPHP1 mice become arrested at an early stage of differentiation and proliferate to form cysts. We demonstrate that Niban1 is a specific molecular marker of cystic cells in both mice and human NPHP1. Conclusion: In summary, we report a novel subpopulation of DCT cells, marked by Niban1, that are classified as cystic cells in the NPHP1 mice kidney. These results offer fresh insights into the cellular and molecular basis of cystogenesis in NPH.

Reducing GEF-H1 Expression Inhibits Renal Cyst Formation, Inflammation, and Fibrosis via RhoA Signaling in Nephronophthisis.

Nephronophthisis (NPHP) is the most prevalent monogenic disease leading to end-stage renal failure in childhood. RhoA activation is involved in NPHP pathogenesis. This study explored the role of the RhoA activator guanine nucleotide exchange factor (GEF)-H1 in NPHP pathogenesis. We analyzed the expression and distribution of GEF-H1 in NPHP1 knockout (NPHP1KO) mice using Western blotting and immunofluorescence, followed by GEF-H1 knockdown. Immunofluorescence and renal histology were used to examine the cysts, inflammation, and fibrosis. A RhoA GTPase activation assay and Western blotting were used to detect the expression of downstream GTP-RhoA and p-MLC2, respectively. In NPHP1 knockdown (NPHP1KD) human kidney proximal tubular cells (HK2 cells), we detected the expressions of E-cadherin and α-smooth muscle actin (α-SMA). In vivo, increased expression and redistribution of GEF-H1, and higher levels of GTP-RhoA and p-MLC2 in renal tissue of NPHP1KO mice were observed, together with renal cysts, fibrosis, and inflammation. These changes were alleviated by GEF-H1 knockdown. In vitro, the expression of GEF-H1 and activation of RhoA were also increased, with increased expression of α-SMA and decreased E-cadherin. GEF-H1 knockdown reversed these changes in NPHP1KD HK2 cells. Thus, the GEF-H1/RhoA/MLC2 axis is activated in NPHP1 defects and may play a pivotal role in NPHP pathogenesis.

[Analysis of SALL1 gene variant in a boy with Townes-Brocks syndrome without anal atresia].

OBJECTIVE: To explore the genetic basis for a child presented with renal failure and multi-cystic dysplastic kidney without anal atresia. METHODS: Peripheral blood sample of the child and his parents were collected and subjected to whole exome sequencing. Candidate variant was verified by Sanger sequencing. RESULTS: The 40-day-old infant had presented with vomiting brown matter in a 7 days neonate and was transferred for kidney failure. Clinical examination has discovered renal failure, polycystic renal dysplasia, congenital hypothyroidism, bilateral thumb polydactyly, sensorineural hearing loss and preauricular dermatophyte. Genetic testing revealed that he has harbored a previously unreported c.824delT, p.L275Yfs*10 frameshift variant of SALL1 gene, which was confirmed by Sanger sequencing as de novo. CONCLUSION: The patient was diagnosed with Townes-Brocks syndrome due to the novel de novo variant of SALL1 gene. Townes-Brocks syndrome without anal atresia is rare. Above finding has also enriched the mutational spectrum of the SALL1 gene.

Overexpression of smad7 inhibits the TGF-ß/Smad signaling pathway and EMT in NPHP1-defective MDCK cells.

BACKGROUND: Nephronophthisis (NPHP) is a kind of ciliopathy. Interstitial fibrosis occurs at the early stage of the disease. TGF-ß/Smad is a key signaling pathway in regulating interstitial fibrosis and epithelial-mesenchymal transition (EMT). In this study, we explored the activation of the TGF-ß/Smad signaling pathway and EMT in NPHP1-defective MDCK cells to further understand the pathogenesis of NPHP. METHODS: NPHP1-knockdown (NPHP1KD) MDCK cells were constructed by recombinant lentiviral short hairpin RNA, and NPHP1-knockout (NPHP1KO) MDCK cells were constructed by using the CRISPR/Cas9 technique. The morphology and migration ability were observed under a microscope. Western blotting was used to detect the expression of E-cadherin, ß-catenin, α-smooth muscle actin (α-SMA), fibroblast-specific protein-1(FSP1), TGF-ß1, Smad2, Smad3, p-Smad3, Smad4 and Smad7. The localization of Smad3 was determined by immunofluorescence assay. RESULTS: NPHP1KD and NPHP1KO MDCK cells were spindle-shaped and presented EMT-like changes. E-cadherin and ß-catenin expression decreased, while α-SMA and FSP1 expression increased; the TGF-ß/Smad signaling pathway was activated, Smad2, Smad3, p-Smad3 and Smad4 expression increased, Smad3 translocated to nuclear and Smad7 expression decreased compared with those in wild type MDCK cells. Overexpression of Smad7 reversed these changes to different degrees. CONCLUSIONS: Our results indicate that NPHP1 defects induce the activation of the TGF-ß/Smad signaling pathway and EMT in MDCK cells. These factors may be implicated in the pathogenesis of interstitial fibrosis in NPHP.

An Nphp1 knockout mouse model targeting exon 2-20 demonstrates characteristic phenotypes of human nephronophthisis.

Nephronophthisis (NPH) is the most prevalent monogenetic disorder leading to end-stage renal failure (ESRD) in childhood. Mutations in Nphp1, encoding a cilia-localized protein, account for the majority of NPH cases. Despite its identification many years ago, Nphp1 deletions targeting exon 4 or exon 20 have not reproduced the histological features of human NPH in murine models. In this study, we deleted exon 2-20 of Nphp1 by CRISPR/Cas9 gene editing to create a near-total knockout (KO) mouse model (Nphp1del2-20/del2-20). Nphp1del2-20/del2-20 mice faithfully reproduced the renal and extrarenal phenotypes associated with human NPH, including renal cyst development, tubular basement membrane thickening, retinal degeneration and abnormal spermatogenesis. Importantly, Nphp1 re-expression using an adenoviral-associated-virus-9 vector could partially rescue both renal and retinal phenotypes in Nphp1del2-20/del2-20 mice. Our results reported the first relevant Nphp1 mouse model with renal phenotypes for human disease. It will be a valuable model for future studies of Nphp1 function and to develop novel treatments for this common childhood disease.

Cyclosporine A relieved proteinuria and hypoproteinemia in DGKE nephropathy.

BACKGROUND: The DGKE gene encodes the diacylglycerol kinase epsilon (DGKε). Loss-of-function mutations of DGKE caused a group of rare renal diseases, which are called DGKE nephropathy. We report the clinical manifestations and therapeutic effects of a patient diagnosed with DGKE nephropathy. CASE REPORT: The patient's initial symptoms were fever, diarrhea, eyelid edema, acute anemia, acute thrombocytopenia, an elevation of plasm D-dimer, proteinuria, microscopic hematuria, without oliguria or renal insufficiency at the age of 7.6 months. Hemolytic uremic syndrome was diagnosed. His proteinuria and hematuria turned out negative 2 months later. Proteinuria was noticed again at the age of 5.5-year old when he was brought to the hospital because of failure to thrive. Since then, he had been noticed with persistent proteinuria. RESULTS: Genetic analysis revealed 2 novel heterozygous mutations on DGKE of the patient. Renal pathology mimicked membrane proliferative glomerulonephritis (MPGN). CONCLUSIONS: After a 5-month treatment of cyclosporine A (CsA), proteinuria and hypoproteinemia have relieved apparently. We also observed an improvement of his growth.

COQ2 mutation associated isolated nephropathy in two siblings from a Chinese pedigree.

BACKGROUD: Coenzyme Q10 (CoQ10) is involved in the biosynthesis of adenosine triphosphate (ATP), and is most abundant in the mitochondrial membrane. The primary CoQ10 deficiency caused by COQ2 defect is mostly manifested as encephalopathy, encephalopathy with nephropathy, and rarely as an isolated nephrotic syndrome. METHODS: Clinical and pathological data and peripheral blood samples of 2 siblings with steroid-resistant nephrotic syndrome (SRNS) and their family members of a Chinese pedigree were collected. DNA was extracted and subjected to next-generation sequencing of target genes of hereditary nephropathy. RESULTS: Compound heterozygous mutations of COQ2 (c.1058A > G, p.Y353C, paternal and c.973A > G, p.T325A, maternal)were identified in both siblings of the pedigree. Mutation of p.Y353C was novel. The proband was a girl, who presented with SRNS at the age of 7 months. CoQ10 was administered after the gene sequencing results came out. Proteinuria decreased gradually to 1+, occasionally negative. The child was normal in growth and intelligence. She is now 4 years old. The second patient was her elder brother. He was found to have SRNS at the age of 2 years old. Renal pathology indicated focal segmental glomerulosclerosis (FSGS). Electronic microcopy revealed that a large quantity of mitochondria with normal contour was accumulated within the podocytes. Both patients were in normal intelligence without convulsion. CONCLUSION: The 2 cases harboring COQ2compound heterozygous mutations presented with isolated SRNS, with a renal pathology of FSGS and a large quantity of mitochondria with normal contour accumulated within the podocytes. CoQ10 was efficacy in eliminating proteinuria.

Clinical and pathological features and varied mutational spectra of pathogenic genes in 55 Chinese patients with nephronophthisis.

BACKGROUND: Nephronophthisis (NPHP) is the most common genetic cause of end-stage renal disease (ESRD) in children. This study was performed to explore the pathogenic gene mutations and clinical and pathological features of Chinese patients with NPHP. METHODS: Patients for whom causative mutations were not identified in our previous study, as well as those recruited later, were subjected to whole-exome next-generation sequencing (NGS) or the exome of 63 primary cilia disease genes. RESULTS: We recruited 55 patients (27 boys and 28 girls) from 48 families, mainly from South China. We subjected 35 patients to NGS. Disease-causing mutations were revealed in seven more families (nine patients) by NGS. In total, disease-causing mutations were identified in 25 patients from 19 families, accounting for 39.6% (19/48) of all families, and novel mutation rate was 77.8% (35/45). NPHP1 and NPHP3 mutations were identified in 14.6% (7/48) and 12.5% (6/48) of all families, respectively. The patient with CEP83 mutations presented with prominent glomerular cysts and glomeruli dysplasia without extrarenal involvement. CONCLUSION: A high novel mutation rate was identified, and disease-causing mutations of NPHP3 prevailed in this group of Chinese NPHP patients. This is the second report of a patient with CEP83 mutations.

Two Chinese nephronophthisis pedigrees harbored a compound heterozygous deletion with a point mutation in NPHP1.

NPHP1 is the most prevalent genetic factor in the development of juvenile nephronophthisis (NPHP). In our previous study, NPHP1 homozygous point mutations were detected by Sanger sequencing in three cases from two nonconsanguineous pedigrees. However, mutant sites were detected in only one parent from each respective pedigree. To investigate whether other disease-causing mutations were present, targeted exome sequencing (TES) of 63 ciliopathy genes was performed in the probands of the two pedigrees. In addition to the previously detected point mutations, a complete heterozygous deletion of NPHP1 (1-20 exons) in the other allele was found in each of the three patients. The deletions were inherited from one parent of each pedigree. These is the first report of Chinese NPHP patients harboring a complete heterozygous deletion of NPHP1 in one allele and a point mutation in the other one. The study demonstrated that TES is helpful in identifying complicated mutations in patients with NPHP.

[Clinical and pathological features and the misdiagnosis of childhood Alport syndrome: a retrospective analysis of 91 cases].

OBJECTIVE: To explore the clinical and pathological features and the diagnosis of childhood Alport syndrome (AS). METHODS: A retrospective analysis was performed on clinical data of 91 children with AS. RESULTS: Hematuria was observed in all 91 patients, of whom 86 were accompanied with proteinuria. Sixty-one children with X-Linked AS (XL-AS) had positive family history. Renal biopsy was performed on 82 children. Mild to moderate mesangial proliferation was observed in 74 cases. Small amounts of immune complexes deposits in the glomerular mesangial area were observed in 48 cases. Glomerular basement membrane (GBM) attenuation, thickening and layering were observed in 53 cases by electron microscopy (EM). In 63 cases receiving renal tissue type IV collagen α3 and α5 chain immunofluorescence detection, 58 were diagnosed with AS, including 53 cases of XL-AS and 5 cases of autosomal recessive AS. In 91 cases of AS, 58 were diagnosed as AS by renal tissue type IV collagen α3 and α5 chain immunofluorescence, 21 were diagnosed by EM, one was diagnosed by skin biopsy, and 12 were diagnosed by gene detection. Six novel mutations of COL4A5 gene were found. Forty-five cases were misdiagnosed before the diagnosis of AS. Forty-one of the 45 cases received steroids and/or immunosuppressant therapy. CONCLUSIONS: The clinical manifestations and pathological changes are not specific in children with AS, resulting in a higher rate of misdiagnosis. Typical lesions of GBM under EM are only observed in a part of patients. There is a high novel mutation rate of COL4A5 in the detected AS children.

WT1 mutation-associated nephropathy: a single-center experience
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This study explored Wilms' tumor 1 (WT1) mutations in children with, or suspected of having, steroid-resistant nephrotic syndrome (SRNS), referred to or treated in our hospital in the past 6 years as well as the correlation between genotype and phenotype in WT1 mutation-associated nephropathy in Chinese patients. In total, 76 patients participated in the study. WT1 mutations were identified in 15 patients, 5 of whom harbored splice-site mutations in intron 9. Four of these 5 patients exhibited early onset of nephropathy and rapid deterioration of renal function. Missense mutations were detected in 8 patients, 4 of whom harbored hot-site mutations and had early-onset proteinuria. Of these 4 patients, rapid progression to end-stage renal disease was only observed in 1. Nonsense mutations were identified in 2 patients; both had a large number of immature glomeruli in the kidney cortex. Calcineurin inhibitors (CNI) were administered in 8 patients. Two patients with missense mutations and 1 patient with a nonsense mutation achieved complete remission. Two patients with missense mutations and 2 with splice-site mutations showed an improvement. One patient with a splice-site mutation showed no changes. In conclusion, a high WT1 mutation rate was observed in this group of SRNS patients. Patients with splice-site mutations experienced a rapid disease progression, and patients harboring nonsense mutations showed a prominent glomerular developmental delay. CNI therapy was effective in patients with WT1 missense mutations and nonsense mutations.
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Increased incidence of osteoarthritis of knee joint after ACL reconstruction with bone-patellar tendon-bone autografts than hamstring autografts: a meta-analysis of 1,443 patients at a minimum of 5 years.

PURPOSE: The objective of this study was to evaluate the effectiveness of BPTB autografts versus HT autografts at a minimum of 5 years after anterior cruciate ligament (ACL) reconstruction. METHODS: A systematical search of literature was performed in PubMed, Embase and the Cochrane library to identify published randomized controlled trials (RCT) or prospective cohort studies (PCS) relevant to ACL reconstruction comparing BPTB and HT autografts. The results of the eligible studies were analysed in terms of objective International Knee Documentation Committee (IKDC) scores, return to preinjury activity level, KT-1000, Lachman test, pivot shift test, anterior knee pain, kneeling pain, extension loss, and flexion loss, graft failure and radiographic outcomes. Study quality was assessed by using the Coleman methodology score for included studies. Two reviewers independently assessed each study for quality and extracted data. Subgroup analysis of the primary outcomes was conducted according to the type of study design (RCT or PCS). RESULTS: Twelve RCTs, two PCS including 1,443 patients comparing hamstring and patellar tendon autografts were identified. The results of the meta-analysis showed that there were no significant differences between BPTB and HT in terms of objective IKDC score (P = 0.83), return to preinjury activity (P = 0.69), KT-1000 (P = 0.12), Lachman test (P = 0.76), pivot shift test (P = 0.11), extension deficit (P = 0.09), flexion deficit (P = 0.71) and graft failure (P = 0.22). However, outcomes in favour of HT autografts were found in terms of anterior knee pain (P = 0.0001) and kneeling pain (P = 0.001). Radiographic evidence of osteoarthritis (OA) showed that incidence of OA was significantly higher in BPTB groups compared with HT groups based on IKDC system. These findings were still robust during the sensitivity analysis. Results from subgroup analysis of the primary outcomes were consistent with the overall analysis. CONCLUSION: Meta-analysis of prospective trials did not detect any significant differences in clinical results, as evidenced by the objective IKDC score, return to preinjury activity level, KT-1000, Lachman test, pivot shift test, extension loss, flexion loss and graft failure. However, the meta-analysis revealed that ACL reconstruction with BPTB autografts resulted in increased anterior knee pain and kneeling pain compared with hamstring autografts. Increased incidence of OA was found after ACL reconstruction at a minimum of 5 years in BPTB group compared with HT autografts. This result should be cautiously interpreted. More high-quality RCT with strictly specified inclusion criteria are highly required before drawing a reliable conclusion.

[Establishment of a rat model of acute liver failure by a modified 90% bloodless hepatectomy and by D-galactosamine and lipopolysaccharide injection].

OBJECTIVE: To compare the effects of different approaches to establishing rat models of acute liver failure (ALF). METHODS: Sixty-eight Sprague-Dawley rats were randomly divided into 3 groups for establishing ALF models using 3 different approaches, namely conventional hepatectomy for resecting 90% liver tissue as described by Higgins and Anderson, modified bloodless hepatectomy for resecting 90% liver tissue, and intraperitoneal injections of 700 mg/kg D-galactosamine (D-gal) and 5 µg/kg lipopolysaccharide (LPS). The mortality of the rats due to postoperative bleeding and survival rate at 7 days after the surgery were recorded. The levels of alanine aminotransferase (ALT), total bilimbin (Tbil), albumin (ALB), NH3, glucose (Glu) and prothrombin time (PT) were monitored, and histopathologies of the liver were examined at 24 and 72 h after the surgery. RESULTS: The mortality rate due to postoperative bleeding was higher in conventional hepatectomy group than in the modified surgical group (15% vs 0). The survival rate at 7 days was 25%, 0%, 15% in conventional surgical group, modified surgical group and drug injection group, respectively. In the latter two groups, significant changes of ALT, Tbil, ALB, NH3, Glu, and PT were recorded at 24 and 72 h after the modeling (P<0.05), and these changes were the most obvious at 24 h in modified surgical group and at 72 h in the drug injection group; ALB in both groups declined to the lowest at 7 days and then increased gradually. Liver cell degeneration and necrosis were found in modified surgical group and drug injection group at 24 h and 72 h after the modeling. CONCLUSION: Both the modified 90% bloodless hepatectomy and injections of D-gal and LPS can be used to establish ideal rat models of ALF to suit different ALF-related researches.