Gene transfer to the rat kidney in vivo and ex vivo using an adenovirus vector: factors influencing transgene expression.

BACKGROUND: The characteristics of adenovirus-mediated gene transfer into the kidney are not well examined. We studied the effects of contact time and temperature on adenovirus-mediated transgene expression in rat kidneys, using catheter-based in vivo gene transfer and a rat renal transplant model ex vivo. METHODS: An adenovirus vector containing the luciferase (Ad-Luc) or beta-galactosidase (Ad-LacZ) gene was introduced in vivo into the kidney via a renal artery catheter. Various contact times and temperatures were evaluated. Ex vivo, the renal graft was injected with Ad-Luc through the renal artery, chilled for 60 min and then transplanted. Luciferase expression was evaluated periodically by a non-invasive bioimaging system or histology. Cells expressing the LacZ gene were identified by immunoelectron microscopy. RESULTS: In in vivo gene transfer, successful transgene expression was achieved; however, its efficiency was independent of contact time or temperature. In ex vivo gene transfer, transgene expression in the renal graft peaked early and gradually decreased. Strong gene expression was observed in the recipients' livers. LacZ expression was detected in fibroblasts, parietal epithelial cells of Bowman's capsule, mesangial cells, podocytes and tubular cells. CONCLUSIONS: This study generated new information about in vivo and ex vivo gene transfer into the kidney, which would be useful for renal gene therapy.     

AKI Recovery Induced by Mesenchymal Stromal Cell-Derived Extracellular Vesicles Carrying MicroRNAs

Phenotypic changes induced by extracellular vesicles have been implicated in mesenchymal stromal cell–promoted recovery of AKI. MicroRNAs are potential candidates for cell reprogramming toward a proregenerative phenotype. The aim of this study was to evaluate whether microRNA deregulation inhibits the regenerative potential of mesenchymal stromal cells and derived extracellular vesicles in a model of glycerol-induced AKI in severe combined immunodeficient mice. We generated mesenchymal stromal cells depleted of Drosha to alter microRNA expression. Drosha-knockdown cells produced extracellular vesicles that did not differ from those of wild-type cells in quantity, surface molecule expression, and internalization within renal tubular epithelial cells. However, these vesicles showed global downregulation of microRNAs. Whereas wild-type mesenchymal stromal cells and derived vesicles administered intravenously induced morphologic and functional recovery in AKI, the Drosha-knockdown counterparts were ineffective. RNA sequencing analysis showed that kidney genes deregulated after injury were restored by treatment with mesenchymal stromal cells and derived vesicles but not with Drosha-knockdown cells and vesicles. Gene ontology analysis showed in AKI an association of downregulated genes with fatty acid metabolism and upregulated genes with inflammation, matrix-receptor interaction, and cell adhesion molecules. These alterations reverted after treatment with wild-type mesenchymal stromal cells and extracellular vesicles but not after treatment with the Drosha-knockdown counterparts. In conclusion, microRNA depletion in mesenchymal stromal cells and extracellular vesicles significantly reduced their intrinsic regenerative potential in AKI, suggesting a critical role of microRNAs in recovery after AKI.     

Urinary Tract Effects of HPSE2 Mutations

Urofacial syndrome (UFS) is an autosomal recessive congenital disease featuring grimacing and incomplete bladder emptying. Mutations of HPSE2, encoding heparanase 2, a heparanase 1 inhibitor, occur in UFS, but knowledge about the HPSE2 mutation spectrum is limited. Here, seven UFS kindreds with HPSE2 mutations are presented, including one with deleted asparagine 254, suggesting a role for this amino acid, which is conserved in vertebrate orthologs. HPSE2 mutations were absent in 23 non-neurogenic neurogenic bladder probands and, of 439 families with nonsyndromic vesicoureteric reflux, only one carried a putative pathogenic HPSE2 variant. Homozygous Hpse2 mutant mouse bladders contained urine more often than did wild-type organs, phenocopying human UFS. Pelvic ganglia neural cell bodies contained heparanase 1, heparanase 2, and leucine-rich repeats and immunoglobulin-like domains-2 (LRIG2), which is mutated in certain UFS families. In conclusion, heparanase 2 is an autonomic neural protein implicated in bladder emptying, but HPSE2 variants are uncommon in urinary diseases resembling UFS.     

Expression of ras gene family as result of compensatory renal growth in mice

Summary We have examined several gene expressions during the process of compensatory renal growth in mice following unilateral nephrectomy. On the 3rd, 5th and 7th days after operation in young mice (age: 5w), unilateral nephrectomy induced weight gain of the remaining kidney, but not in adults (age: 15w). It also induced maximum expression of c-H-ras and c-K-ras on the 3rd day in both young and adult mice, but there was no increase in N-ras in either. The expression levels of c-H-ras and c-K-ras were higher in young mice than in adults. However no expression of c-myc was detected at any point. Expression of metallothionein-I (MT-I) gene was detected during the first 12 h after unilateral nephrectomy both in the liver and the contralateral kidney. These data suggest that c-H-ras and c-K-ras gene expressions are in some way related to compensatory renal growth in mice and may be strongly related to hyperplasia in the contralateral kidney.     

Human renal allograft rejection: Immune mechanisms, molecular correlates and treatment strategies

Summary: Through the release of cytokines and cell-to-cell interactions, a diverse assembly of lymphocytes, including CD4+ cells, CD8+ cytotoxic T cells, antibody-forming B cells, and other pro-inflammatory leucocytes are recruited into the anti-allograft response. In this review, we discuss immune effector mechanisms, molecular correlates of rejection and therapeutic protocols. the recent expansion in our knowledge, coupled with the discovery and use of new immunosuppressants in the clinic, engenders optimism regarding management of allograft rejection, the most serious frequent complication in organ transplantation.     

Kidney function in adults born with unilateral renal agenesis or nephrectomized in childhood

We have evaluated the long-term prognosis in an unselected group of adult patients either uni-nephrectomized in childhood because of hydronephrosis or born with unilateral renal agenesis. Thirty-six patients aged 7–47 years were followed for 7–40 years. In 23 control subjects aged 20–47 years the glomerular filtration rate (GFR) and thep-aminohippuric acid clearance (C_PAH) did not change significantly with age. In patients with a single kidney the size of that kidney was larger and GFR and C_PAH were higher than single kidney values in control subjects. However, in patients with a single kidney since childhood the GFR and the C_PAH declined slowly but significantly during the follow-up period. Significant microalbuminuria occurred in 47% of the patients with a single kidney and was more frequent with a longer follow-up period. No patient had renal insufficiency or a marked increase in arterial blood pressure. We conclude that in patients with a single kidney since childhood the long-term prognosis is good, but the late decrease in GFR and increase in albumin excretion may indicate a moderate risk for premature renal damage.     

Relationship between premature ejaculation and genetic polymorphisms of the dopamine transporter gene (SLC6A3)

What’s known on the subject? and What does the study add? The process of ejaculation is highly influenced by genetic and neurobiological factors. Central dopaminergic drugs facilitate ejaculation. Genetic variation in SLC6A3 may alter the expression of dopamine transporter gene (DAT). This study evaluated the associations between genetic polymorphisms of the DAT and PE. A statistically significant association was observed between the presence of 9‐repeat allele and 9/10 genotype and PE. The presence of 7‐repeat allele had protective effect against PE.

OBJECTIVE

? To investigate the possible relationships between premature ejaculation (PE) polymorphisms in the dopamine transporter (DAT) gene (SLC6A3, DAT1), which has a polymorphic 40 base pair (40 bp) variable number of tandem repeats (VNTR) sequence in the 3′‐untranslated region (3′ VNTR).

PATIENTS AND METHODS

? Cohorts of 270 Iranian men with PE and 266 age‐matched healthy Iranian subjects were genotyped for the DAT1‐VNTR polymorphism.

RESULTS

? The 10‐repeat allele frequencies were similar in the control (90.2%) and patient groups (88.5%) (P = 0.8). ? A statistically significant association was observed between the presence of the nine‐repeat allele and PE (chi‐squared test = 4.346, odds ratio [OR] = 2.46, 95% confidence interval [CI] = 1.57–3.15, P = 0.026). ? The frequencies of the 9/10 genotype were also significantly higher in the PE patients than in normal controls (chi‐squared test = 4.466, OR = 2.47, 95% CI = 1.52–3.21, P = 0.028). The presence of the seven‐repeat allele had a protective effect against PE (chi‐squared test = 2.324, OR = 0.62, 95% CI = 0.47–0.89, P = 0.034).

CONCLUSIONS

? The findings of the present study suggest that DAT1‐VNTR polymorphisms resulting in higher dopamine concentrations were associated with vulnerability to PE. ? Further studies are needed to replicate these results and to evaluate the role of inconsistency in the DAT genes and how this affects the development of PE.     

Nephron Deficiency and Predisposition to Renal Injury in a Novel One-Kidney Genetic Model

Some studies have reported up to 40% of patients born with a single kidney develop hypertension, proteinuria, and in some cases renal failure. The increased susceptibility to renal injury may be due, in part, to reduced nephron numbers. Notably, children who undergo nephrectomy or adults who serve as kidney donors exhibit little difference in renal function compared with persons who have two kidneys. However, the difference in risk between being born with a single kidney versus being born with two kidneys and then undergoing nephrectomy are unclear. Animal models used previously to investigate this question are not ideal because they require invasive methods to model congenital solitary kidney. In this study, we describe a new genetic animal model, the heterogeneous stock-derived model of unilateral renal agenesis (HSRA) rat, which demonstrates 50%–75% spontaneous incidence of a single kidney. The HSRA model is characterized by reduced nephron number (more than would be expected by loss of one kidney), early kidney/glomerular hypertrophy, and progressive renal injury, which culminates in reduced renal function. Long-term studies of temporal relationships among BP, renal hemodynamics, and renal function demonstrate that spontaneous single-kidney HSRA rats are more likely than uninephrectomized normal littermates to exhibit renal impairment because of the combination of reduced nephron numbers and prolonged exposure to renal compensatory mechanisms (i.e., hyperfiltration). Future studies with this novel animal model may provide additional insight into the genetic contributions to kidney development and agenesis and the factors influencing susceptibility to renal injury in individuals with congenital solitary kidney.     

MicroRNA-17~92 Is Required for Nephrogenesis and Renal Function

Deletion of all microRNAs (miRNAs) in nephron progenitors leads to premature loss of these cells, but the roles of specific miRNAs in progenitors have not been identified. Deletions in the MIR17HG cluster (miR-17~92 in mice), detected in a subset of patients with Feingold syndrome, represent the first miRNA mutations to be associated with a developmental defect in humans. Although MIR17HG is expressed in the developing kidney, and patients with Feingold syndrome caused by MYCN mutations have renal anomalies, it remains unclear to what extent MIR17HG contributes to renal development and function. To define the role of miR-17~92, we generated mice with a conditional deletion of miR-17~92 in nephron progenitors and their derivatives. The nephron progenitor population was preserved in these mice; however, this deletion impaired progenitor cell proliferation and reduced the number of developing nephrons. Postnatally, mutant mice developed signs of renal disease, including albuminuria by 6 weeks and focal podocyte foot process effacement and glomerulosclerosis at 3 months. Taken together, these data support a role for this miRNA cluster in renal development, specifically in the regulation of nephron development, with subsequent consequences for renal function in adult mice.     

Renal agenesis: A meta-analysis of its prevalence and clinical characteristics based on 15 641 184 patients

Our objective was to analyse the newest relevant data on worldwide prevalence and associated symptoms of renal agenesis (RA). This meta-analysis builds on previous systematic reviews to include bilateral RA, its symptoms and data on gender, unilateral RA and anomaly location prevalence. Review of available data included records in English and other languages from PubMed, Embase, ScienceDirect, Web of Science, SciELO, BIOSIS, Current Content Connect Korean Journal Database and Russian Citation Index and Google. A total of 15 641 184 patients were analysed in relation to the prevalence of RA. The pooled prevalence of RA was 0.03% (95% CI: 0.03%–0.04%). Based on 500 subjects, a pooled prevalence of 47.96% (95% CI: 31.55%–64.58%) for unilateral and 52.04% (95% CI: 35.42%–68.45%) for bilateral RA has been set. Our study presents the newest generalized findings on bilateral RA. There appears to be universal disease and symptom prevalence with minor differences between world regions, although quality of future observational research should include genomic data. This will provide even further insight into the prognosis of various renal anomalies and their etiologies.     

The Future of Polycystic Kidney Disease Research—As Seen By the 12 Kaplan Awardees

Polycystic kidney disease (PKD) is one of the most common life-threatening genetic diseases. Jared J. Grantham, M.D., has done more than any other individual to promote PKD research around the world. However, despite decades of investigation there is still no approved therapy for PKD in the United States. In May 2014, the University of Kansas Medical Center hosted a symposium in Kansas City honoring the occasion of Dr. Grantham''s retirement and invited all the awardees of the Lillian Jean Kaplan International Prize for Advancement in the Understanding of Polycystic Kidney Disease to participate in a forward-thinking and interactive forum focused on future directions and innovations in PKD research. This article summarizes the contributions of the 12 Kaplan awardees and their vision for the future of PKD research.