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Background: In the past 5 years, type 2 diabetes practice guidelines have shifted to prioritize agents with cardiovascular (CV) and renal benefit. This study assessed whether real-world medication use has changed in line with these evolving guidelines. Methods: We retrospectively examined the treatment patterns (12 months pre and post) of people with T2D (PwT2D) who initiated basal insulin (BI) in either 2015 (cohort 1) , 2017 (cohort 2) , or 2019 (cohort 3) using IBM® MarketScan® Databases. Between-group differences were analyzed via t-test or chi-square as appropriate. Results: In the study period, 6,396,441 PwT2D were identified. The number of PwT2D initiating BI was 17,801/948,805 (1.88%) in 2015 vs. 10,870/622,455 (1.75%) in 2019 and a progressively larger share of BI initiators had prior GLP-1RA use (14.8% in cohort 1 vs. 25.2% in cohort 3; p < 0.001) or SGLT-2i use (11.4% in cohort 1 vs. 20.5% in cohort 3; p < 0.001) . Furthermore, in patients without prior GLP-1RA, SGLT-2i, or bolus use who initiated GLP-1RA or SGLT-2i in the first year of BI, time to first GLP-1RA (132.4 days in cohort 1 vs. 120.5 days in cohort 3; p = 0.02) or SGLT-2i (131.5 days in cohort 1 vs. 113.3 days in cohort 3; p = 0.002) decreased. Conclusions: Real-world data suggests growing and earlier use of GLP-1RA and SGLT-2i among BI users, and a growing proportion of PwT2D on BI-GLP-1RA combination treatment, in line with changing practice guidelines. Disclosure D. Schapiro: Employee; Eli Lilly and Company. A. Meeks: Employee; Eli Lilly and Company. D. Liu: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. F. Gelsey: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. R. Juneja: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. M. Perez-nieves: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. A. Huang: None. Funding Eli Lilly and Company

Background: HbA1c is a primary measure of glycemic control and managing HbA1c may help reduce the risk of complications. This study aimed to describe trends in HbA1c by insulin regimen. Methods: This was a retrospective analysis of cross-sectional surveys collected from the National Health and Nutrition Examination Survey between 2009-2018. Mean HbA1c and proportion achieving guideline- and HCP-recommended (i.e. personalized) HbA1c targets were evaluated in aggregate and over time in adults (18-64 years) with type 1 (T1DM) or type 2 (T2DM) diabetes using mealtime insulin (MTI) or basal insulin only. Trends over time between 2009-2018 were evaluated after adjusting for age, gender, race/ethnicity. The analysis included the strata, clusters, and weighting of the complex survey design. Results: From 2009-2018, 26.1% of people with T1DM (weighted n=891,194; mean HbA1c [SE] 7.9% [0.2]) , 24.8% with T2DM MTI (weighted n=1,591,183; mean HbA1c [SE] 8.6% [0.2]) , and 11.2% with T2DM basal only (weighted n=1,087,895; mean HbA1c [SE] 8.6% [0.2]) achieved the ADA recommended HbA1c goal of Conclusions: Across all insulin regimens based off the most recent NHANES data, ∼75-90% of individuals are not achieving ADA-recommended or personalized HbA1c goals. Emerging treatment tools (e.g. new technologies, advanced insulins, and time in range metrics) may facilitate improved diabetes outcomes. Disclosure E.R.Hankosky: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. D.Schapiro: Employee; Eli Lilly and Company. K.B.Gunn: Employee; Eli Lilly and Company. E.Lubelczyk: Employee; Eli Lilly and Company. J.Mitroi: None. D.R.Nelson: Employee; Eli Lilly and Company. Funding Eli Lilly and Company

Limited US real-world evidence exists on the effect of substantial changes in weight on HbA1c among people with T2D. People with T2D were identified from 2010-2018 in the IQVIA Ambulatory EMR database. The date of the first observed weight value was defined as the index date and patients were required to have an additional weight value at 1 year (±90 days) post-index date. Patients were stratified by weight change between index and 1 year post-index date. HbA1c was evaluated at index, 6 months, and 1 year post-index date. Of the 1,061,354 patients evaluated, 20.2% gained weight, 53.9% had no weight change, and 10.6% lost 3-5%, 10.7% lost 5-10%, 2.8% lost 10-15%, and 1.7% lost ≥15% of their weight at the index date (i.e., index weight) at 1 year of follow-up. Of note, patients with the largest weight loss had the highest index weight (range: 203.7lb in patients with weight gain to 245.9lb in patients with ≥15% weight loss) . Mean index HbA1c was similar across subgroups as was the percent of patients with index HbA1c In summary, HbA1c reduction was greater with increasing amount of weight lost during the one year of follow-up. Patients with weight loss ≥15% reduced HbA1c by an average of 1.2% of the index value at 1 year of follow-up. Disclosure S.Shinde: None. V.Thieu: None. A.Kwan: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. K.F.Houghton: None. D.Schapiro: Employee; Eli Lilly and Company. J.Meyers: Other Relationship; Eli Lilly and Company.

Background Although studies have identified >55 genes as causing steroid-resistant nephrotic syndrome (SRNS) and localized its pathogenesis to glomerular podocytes, the disease mechanisms of SRNS remain largely enigmatic. We recently reported that individuals with mutations in COQ6, a coenzyme Q (also called CoQ 10 , CoQ, or ubiquinone) biosynthesis pathway enzyme, develop SRNS with sensorineural deafness, and demonstrated the beneficial effect of CoQ for maintenace of kidney function. Methods To study COQ6 function in podocytes, we generated a podocyte-specific Coq6 knockout mouse ( Coq6 podKO ) model and a transient siRNA-based COQ6 knockdown in a human podocyte cell line. Mice were monitored for development of proteinuria and assessed for development of glomerular sclerosis. Using a podocyte migration assay, we compared motility in COQ6 knockdown podocytes and control podocytes. We also randomly assigned 5-month-old Coq6 podKO mice and controls to receive no treatment or 2,4-dihydroxybenzoic acid (2,4-diHB), an analog of a CoQ precursor molecule that is classified as a food additive by health authorities in Europe and the United States. Results Abrogation of Coq6 in mouse podocytes caused FSGS and proteinuria (>46-fold increases in albuminuria). In vitro studies revealed an impaired podocyte migration rate in COQ6 knockdown human podocytes. Treating Coq6 podKO mice or cells with 2,4-diHB prevented renal dysfunction and reversed podocyte migration rate impairment. Survival of Coq6 podKO mice given 2,4diHB was comparable to that of control mice and significantly higher than that of untreated Coq6 podKO mice, half of which died by 10 months of age. Conclusions These findings reveal a potential novel treatment strategy for those cases of human nephrotic syndrome that are caused by a primary dysfunction in the CoQ 10 biosynthesis pathway.

Item does not contain fulltext Steroid-resistant nephrotic syndrome (SRNS) almost invariably progresses to end-stage renal disease. Although more than 50 monogenic causes of SRNS have been described, a large proportion of SRNS remains unexplained. Recently, it was discovered that mutations of NUP93 and NUP205, encoding 2 proteins of the inner ring subunit of the nuclear pore complex (NPC), cause SRNS. Here, we describe mutations in genes encoding 4 components of the outer rings of the NPC, namely NUP107, NUP85, NUP133, and NUP160, in 13 families with SRNS. Using coimmunoprecipitation experiments, we showed that certain pathogenic alleles weakened the interaction between neighboring NPC subunits. We demonstrated that morpholino knockdown of nup107, nup85, or nup133 in Xenopus disrupted glomerulogenesis. Re-expression of WT mRNA, but not of mRNA reflecting mutations from SRNS patients, mitigated this phenotype. We furthermore found that CRISPR/Cas9 knockout of NUP107, NUP85, or NUP133 in podocytes activated Cdc42, an important effector of SRNS pathogenesis. CRISPR/Cas9 knockout of nup107 or nup85 in zebrafish caused developmental anomalies and early lethality. In contrast, an in-frame mutation of nup107 did not affect survival, thus mimicking the allelic effects seen in humans. In conclusion, we discovered here that mutations in 4 genes encoding components of the outer ring subunits of the NPC cause SRNS and thereby provide further evidence that specific hypomorphic mutations in these essential genes cause a distinct, organ-specific phenotype.

Galloway-Mowat syndrome (GAMOS) is a phenotypically heterogeneous disorder characterized by neurodevelopmental defects combined with renal-glomerular disease, manifesting with proteinuria. To identify additional monogenic disease causes, we here performed whole exome sequencing (WES), linkage analysis, and homozygosity mapping in three affected siblings of an Indian family with GAMOS. Applying established criteria for variant filtering, we identify a novel homozygous splice site mutation in the gene WDR4 as the likely disease-causing mutation in this family. In line with previous reports, we observe growth deficiency, microcephaly, developmental delay, and intellectual disability as phenotypic features resulting from WDR4 mutations. However, the newly identified allele additionally gives rise to proteinuria and nephrotic syndrome, a phenotype that was never reported in patients with WDR4 mutations. Our data thus expand the phenotypic spectrum of WDR4 mutations by demonstrating that, depending on the specific mutated allele, a renal phenotype may be present. This finding suggests that GAMOS may occupy a phenotypic spectrum with other microcephalic diseases. Furthermore, WDR4 is an additional example of a gene that encodes a tRNA modifying enzyme and gives rise to GAMOS, if mutated. Our findings thereby support the recent observation that, like neurons, podocytes of the renal glomerulus are particularly vulnerable to cellular defects resulting from altered tRNA modifications.

Background Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of CKD. The discovery of monogenic causes of SRNS has revealed specific pathogenetic pathways, but these monogenic causes do not explain all cases of SRNS. Methods To identify novel monogenic causes of SRNS, we screened 665 patients by whole-exome sequencing. We then evaluated the in vitro functional significance of two genes and the mutations therein that we discovered through this sequencing and conducted complementary studies in podocyte-like Drosophila nephrocytes. Results We identified conserved, homozygous missense mutations of GAPVD1 in two families with early-onset NS and a homozygous missense mutation of ANKFY1 in two siblings with SRNS. GAPVD1 and ANKFY1 interact with the endosomal regulator RAB5. Coimmunoprecipitation assays indicated interaction between GAPVD1 and ANKFY1 proteins, which also colocalized when expressed in HEK293T cells. Silencing either protein diminished the podocyte migration rate. Compared with wild-type GAPVD1 and ANKFY1, the mutated proteins produced upon ectopic expression of GAPVD1 or ANKFY1 bearing the patient-derived mutations exhibited altered binding affinity for active RAB5 and reduced ability to rescue the knockout-induced defect in podocyte migration. Coimmunoprecipitation assays further demonstrated a physical interaction between nephrin and GAPVD1, and immunofluorescence revealed partial colocalization of these proteins in rat glomeruli. The patient-derived GAPVD1 mutations reduced nephrin-GAPVD1 binding affinity. In Drosophila , silencing Gapvd1 impaired endocytosis and caused mistrafficking of the nephrin ortholog. Conclusions Mutations in GAPVD1 and probably in ANKFY1 are novel monogenic causes of NS. The discovery of these genes implicates RAB5 regulation in the pathogenesis of human NS.

Background Alport syndrome (AS) and atypical hemolytic-uremic syndrome (aHUS) are rare forms of chronic kidney disease (CKD) that can lead to a severe decline of renal function. Steroid-resistant nephrotic syndrome (SRNS) is more common than AS and aHUS and causes 10% of childhood-onset CKD. In recent years, multiple monogenic causes of AS, aHUS and SRNS have been identified, but their relative prevalence has yet to be studied together in a typical pediatric cohort of children with proteinuria and hematuria. We hypothesized that identification of causative mutations by whole exome sequencing (WES) in known monogenic nephritis and nephrosis genes would allow distinguishing nephritis from nephrosis in a typical pediatric group of patients with both proteinuria and hematuria at any level. Methods We therefore conducted an exon sequencing (WES) analysis for 11 AS, aHUS and thrombotic thrombocytopenic purpura-causing genes in an international cohort of 371 patients from 362 families presenting with both proteinuria and hematuria before age 25 years. In parallel, we conducted either WES or high-throughput exon sequencing for 23 SRNS-causing genes in all patients. Results We detected pathogenic mutations in 18 of the 34 genes analyzed, leading to a molecular diagnosis in 14.1% of families (51 of 362). Disease-causing mutations were detected in 3 AS-causing genes (4.7%), 3 aHUS-causing genes (1.4%) and 12 NS-causing genes (8.0%). We observed a much higher mutation detection rate for monogenic forms of CKD in consanguineous families (35.7% versus 10.1%). Conclusions We present the first estimate of relative frequency of inherited AS, aHUS and NS in a typical pediatric cohort with proteinuria and hematuria. Important therapeutic and preventative measures may result from mutational analysis in individuals with proteinuria and hematuria.

Item does not contain fulltext BACKGROUND: Nephrotic syndrome (NS), a chronic kidney disease, is characterized by significant loss of protein in the urine causing hypoalbuminemia and edema. In general, approximately 15% of childhood-onset cases do not respond to steroid therapy and are classified as steroid-resistant NS (SRNS). In approximately 30% of cases with SRNS, a causative mutation can be detected in one of 44 monogenic SRNS genes. The gene LAMA5 encodes laminin-alpha5, an essential component of the glomerular basement membrane. Mice with a hypomorphic mutation in the orthologous gene Lama5 develop proteinuria and hematuria. METHODS: To identify additional monogenic causes of NS, we performed whole exome sequencing in 300 families with pediatric NS. In consanguineous families we applied homozygosity mapping to identify genomic candidate loci for the underlying recessive mutation. RESULTS: In three families, in whom mutations in known NS genes were excluded, but in whom a recessive, monogenic cause of NS was strongly suspected based on pedigree information, we identified homozygous variants of unknown significance (VUS) in the gene LAMA5. While all affected individuals had nonsyndromic NS with an early onset of disease, their clinical outcome and response to immunosuppressive therapy differed notably. CONCLUSION: We here identify recessive VUS in the gene LAMA5 in patients with partially treatment-responsive NS. More data will be needed to determine the impact of these VUS in disease management. However, familial occurrence of disease, data from genetic mapping and a mouse model that recapitulates the NS phenotypes suggest that these genetic variants may be inherited factors that contribute to the development of NS in pediatric patients.

The incidence of nephrolithiasis continues to rise. Previously, we showed that a monogenic cause could be detected in 11.4% of individuals with adult-onset nephrolithiasis or nephrocalcinosis and in 16.7-20.8% of individuals with onset before 18 years of age, using gene panel sequencing of 30 genes known to cause nephrolithiasis/nephrocalcinosis. To overcome the limitations of panel sequencing, we utilized whole exome sequencing in 51 families, who presented before age 25 years with at least one renal stone or with a renal ultrasound finding of nephrocalcinosis to identify the underlying molecular genetic cause of disease. In 15 of 51 families, we detected a monogenic causative mutation by whole exome sequencing. A mutation in seven recessive genes ( AGXT, ATP6V1B1, CLDN16, CLDN19, GRHPR, SLC3A1, SLC12A1 ), in one dominant gene ( SLC9A3R1 ), and in one gene ( SLC34A1 ) with both recessive and dominant inheritance was detected. Seven of the 19 different mutations were not previously described as disease-causing. In one family, a causative mutation in one of 117 genes that may represent phenocopies of nephrolithiasis-causing genes was detected. In nine of 15 families, the genetic diagnosis may have specific implications for stone management and prevention. Several factors that correlated with the higher detection rate in our cohort were younger age at onset of nephrolithiasis/nephrocalcinosis, presence of multiple affected members in a family, and presence of consanguinity. Thus, we established whole exome sequencing as an efficient approach toward a molecular genetic diagnosis in individuals with nephrolithiasis/nephrocalcinosis who manifest before age 25 years.

Item does not contain fulltext BACKGROUND: Congenital anomalies of the kidney and urinary tract (CAKUT) are the most prevalent cause of kidney disease in the first three decades of life. Previous gene panel studies showed monogenic causation in up to 12% of patients with CAKUT. METHODS: We applied whole-exome sequencing to analyze the genotypes of individuals from 232 families with CAKUT, evaluating for mutations in single genes known to cause human CAKUT and genes known to cause CAKUT in mice. In consanguineous or multiplex families, we additionally performed a search for novel monogenic causes of CAKUT. RESULTS: In 29 families (13%), we detected a causative mutation in a known gene for isolated or syndromic CAKUT that sufficiently explained the patient's CAKUT phenotype. In three families (1%), we detected a mutation in a gene reported to cause a phenocopy of CAKUT. In 15 of 155 families with isolated CAKUT, we detected deleterious mutations in syndromic CAKUT genes. Our additional search for novel monogenic causes of CAKUT in consanguineous and multiplex families revealed a potential single, novel monogenic CAKUT gene in 19 of 232 families (8%). CONCLUSIONS: We identified monogenic mutations in a known human CAKUT gene or CAKUT phenocopy gene as the cause of disease in 14% of the CAKUT families in this study. Whole-exome sequencing provides an etiologic diagnosis in a high fraction of patients with CAKUT and will provide a new basis for the mechanistic understanding of CAKUT. 01 september 2018

Background and objectives Steroid-resistant nephrotic syndrome overwhelmingly progresses to ESRD. More than 30 monogenic genes have been identified to cause steroid-resistant nephrotic syndrome. We previously detected causative mutations using targeted panel sequencing in 30% of patients with steroid-resistant nephrotic syndrome. Panel sequencing has a number of limitations when compared with whole exome sequencing. We employed whole exome sequencing to detect monogenic causes of steroid-resistant nephrotic syndrome in an international cohort of 300 families. Design, setting, participants, & measurements Three hundred thirty-five individuals with steroid-resistant nephrotic syndrome from 300 families were recruited from April of 1998 to June of 2016. Age of onset was restricted to Results In 74 of 300 families (25%), we identified a causative mutation in one of 20 genes known to cause steroid-resistant nephrotic syndrome. In 11 families (3.7%), we detected a mutation in a gene that causes a phenocopy of steroid-resistant nephrotic syndrome. This is consistent with our previously published identification of mutations using a panel approach. We detected a causative mutation in a known steroid-resistant nephrotic syndrome gene in 38% of consanguineous families and in 13% of nonconsanguineous families, and 48% of children with congenital nephrotic syndrome. A total of 68 different mutations were detected in 20 of 33 steroid-resistant nephrotic syndrome genes. Fifteen of these mutations were novel. NPHS1, PLCE1, NPHS2, and SMARCAL1 were the most common genes in which we detected a mutation. In another 28% of families, we detected mutations in one or more candidate genes for steroid-resistant nephrotic syndrome. Conclusions Whole exome sequencing is a sensitive approach toward diagnosis of monogenic causes of steroid-resistant nephrotic syndrome. A molecular genetic diagnosis of steroid-resistant nephrotic syndrome may have important consequences for the management of treatment and kidney transplantation in steroid-resistant nephrotic syndrome.

Steroid-resistant nephrotic syndrome (SRNS) is the second most frequent cause of end-stage renal disease (ESRD) among patients manifesting at under 25 years of age. We performed mutation analysis using a high-throughput PCR-based microfluidic technology in 24 single-gene causes of SRNS in a cohort of 72 families, who presented with SRNS before the age of 25 years. Within an 18-month interval, we obtained DNA samples, pedigree information, and clinical information from 77 consecutive children with SRNS from 72 different families seen at Boston Children’s Hospital (BCH). Mutation analysis was completed by combining high-throughput multiplex PCR with next-generation sequencing. We analyzed the sequences of 18 recessive and 6 dominant genes of SRNS in all 72 families for disease-causing variants. We identified the disease-causing mutation in 8 out of 72 (11.1%) families. Mutations were detected in the six genes: NPHS1 (2 out of 72), WT1 (2 out of 72), NPHS2, MYO1E, TRPC6, and INF2. Median age at onset was 4.1 years in patients without a mutation (range 0.5–18.8), and 3.2 years in those in whom the causative mutation was detected (range 0.1–14.3). Mutations in dominant genes presented with a median onset of 4.5 years (range 3.2–14.3). Mutations in recessive genes presented with a median onset of 0.5 years (range 0.1–3.2). Our molecular genetic diagnostic study identified underlying monogenic causes of steroid-resistant nephrotic syndrome in ~11% of patients with SRNS using a cost-effective technique. We delineated some of the therapeutic, diagnostic, and prognostic implications. Our study confirms that genetic testing is indicated in pediatric patients with SRNS.

Background Mutations in ADCK4 (aarF domain containing kinase 4) generally manifest as steroid-resistant nephrotic syndrome and induce coenzyme Q10 (CoQ10) deficiency. However, the molecular mechanisms underlying steroid-resistant nephrotic syndrome resulting from ADCK4 mutations are not well understood, largely because the function of ADCK4 remains unknown. Methods To elucidate the ADCK4's function in podocytes, we generated a podocyte-specific, Adck4-knockout mouse model and a human podocyte cell line featuring knockout of ADCK4. These knockout mice and podocytes were then treated with 2,4-dihydroxybenzoic acid (2,4-diHB), a CoQ10 precursor analogue, or with a vehicle only. We also performed proteomic mass spectrometry analysis to further elucidate ADCK4's function. Results Absence of Adck4 in mouse podocytes caused FSGS and albuminuria, recapitulating features of nephrotic syndrome caused by ADCK4 mutations. In vitro studies revealed that ADCK4-knockout podocytes had significantly reduced CoQ10 concentration, respiratory chain activity, and mitochondrial potential, and subsequently displayed an increase in the number of dysmorphic mitochondria. However, treatment of 3-month-old knockout mice or ADCK4-knockout cells with 2,4-diHB prevented the development of renal dysfunction and reversed mitochondrial dysfunction in podocytes. Moreover, ADCK4 interacted with mitochondrial proteins such as COQ5, as well as cytoplasmic proteins such as myosin and heat shock proteins. Thus, ADCK4 knockout decreased the COQ complex level, but overexpression of ADCK4 in ADCK4-knockout podocytes transfected with wild-type ADCK4 rescued the COQ5 level. Conclusions Our study shows that ADCK4 is required for CoQ10 biosynthesis and mitochondrial function in podocytes, and suggests that ADCK4 in podocytes stabilizes proteins in complex Q in podocytes. Our study also suggests a potential treatment strategy for nephrotic syndrome resulting from ADCK4 mutations.

ADCK4mutations usually manifest as steroid-resistant nephrotic syndrome, and cause coenzyme Q10(CoQ10) deficiency. However, the function of ADCK4 remains obscure. We investigated ADCK4 function using mouse and cell models. Podocyte-specificAdck4deletion in mice significantly reduced survival and caused severe focal segmental glomerular sclerosis with extensive interstitial fibrosis and tubular atrophy, which were prevented by treatment with 2,4-dihydroxybenzoic acid (2,4-diHB), an analog of CoQ10precursor molecule. ADCK4 knockout podocytes exhibited significantly decreased CoQ10level, respiratory chain activity, mitochondrial potential, and dysmorphic mitochondria with loss of cristae formation, which were rescued by 2,4-diHB treatment, thus attributing these phenotypes to decreased CoQ10levels. ADCK4 interacted with mitochondrial proteins including COQ5, and also cytoplasmic proteins including myosin and heat shock proteins. ADCK4 knockout decreased COQ complex levels, and the COQ5 level was rescued by ADCK4 overexpression in ADCK4 knockout podocytes. Overall, ADCK4 is required for CoQ10biosynthesis and mitochondrial function in podocytes.

Nephronophthisis-related ciliopathies (NPHP-RCs) are a group of inherited diseases that are associated with defects in primary cilium structure and function. To identify genes mutated in NPHP-RC, we performed homozygosity mapping and whole-exome sequencing for >100 individuals, some of whom were single affected individuals born to consanguineous parents and some of whom were siblings of indexes who were also affected by NPHP-RC. We then performed high-throughput exon sequencing in a worldwide cohort of 800 additional families affected by NPHP-RC. We identified two ADAMTS9 mutations (c.4575_4576del [p.Gln1525Hisfs(∗)60] and c.194C>G [p.Thr65Arg]) that appear to cause NPHP-RC. Although ADAMTS9 is known to be a secreted extracellular metalloproteinase, we found that ADAMTS9 localized near the basal bodies of primary cilia in the cytoplasm. Heterologously expressed wild-type ADAMTS9, in contrast to mutant proteins detected in individuals with NPHP-RC, localized to the vicinity of the basal body. Loss of ADAMTS9 resulted in shortened cilia and defective sonic hedgehog signaling. Knockout of Adamts9 in IMCD3 cells, followed by spheroid induction, resulted in defective lumen formation, which was rescued by an overexpression of wild-type, but not of mutant, ADAMTS9. Knockdown of adamts9 in zebrafish recapitulated NPHP-RC phenotypes, including renal cysts and hydrocephalus. These findings suggest that the identified mutations in ADAMTS9 cause NPHP-RC and that ADAMTS9 is required for the formation and function of primary cilia.

BACKGROUND: Although studies have identified >55 genes as causing steroid-resistant nephrotic syndrome (SRNS) and localized its pathogenesis to glomerular podocytes, the disease mechanisms of SRNS remain largely enigmatic. We recently reported that individuals with mutations in COQ6, a coenzyme Q (also called CoQ(10), CoQ, or ubiquinone) biosynthesis pathway enzyme, develop SRNS with sensorineural deafness, and demonstrated the beneficial effect of CoQ for maintenace of kidney function. METHODS: To study COQ6 function in podocytes, we generated a podocyte-specific Coq6 knockout mouse (Coq6(podKO)) model and a transient siRNA-based COQ6 knockdown in a human podocyte cell line. Mice were monitored for development of proteinuria and assessed for development of glomerular sclerosis. Using a podocyte migration assay, we compared motility in COQ6 knockdown podocytes and control podocytes. We also randomly assigned 5-month-old Coq6(podKO) mice and controls to receive no treatment or 2,4-dihydroxybenzoic acid (2,4-diHB), an analog of a CoQ precursor molecule that is classified as a food additive by health authorities in Europe and the United States. RESULTS: Abrogation of Coq6 in mouse podocytes caused FSGS and proteinuria (>46-fold increases in albuminuria). In vitro studies revealed an impaired podocyte migration rate in COQ6 knockdown human podocytes. Treating Coq6(podKO) mice or cells with 2,4-diHB prevented renal dysfunction and reversed podocyte migration rate impairment. Survival of Coq6(podKO) mice given 2,4diHB was comparable to that of control mice and significantly higher than that of untreated Coq6(podKO) mice, half of which died by 10 months of age. CONCLUSIONS: These findings reveal a potential novel treatment strategy for those cases of human nephrotic syndrome that are caused by a primary dysfunction in the CoQ(10) biosynthesis pathway.

Galloway-Mowat syndrome (GAMOS) is a severe autosomal-recessive disease characterized by the combination of early-onset steroid-resistant nephrotic syndrome (SRNS) and microcephaly with brain anomalies. To date, mutations of WDR73 are the only known monogenic cause of GAMOS and in most affected individuals the molecular diagnosis remains elusive. We here identify recessive mutations of OSGEP, TP53RK, TPRKB, or LAGE3, encoding the 4 subunits of the KEOPS complex in 33 individuals of 30 families with GAMOS. CRISPR/Cas9 knockout in zebrafish and mice recapitulates the human phenotype of microcephaly and results in early lethality. Knockdown of OSGEP, TP53RK, or TPRKB inhibits cell proliferation, which human mutations fail to rescue, and knockdown of either gene activates DNA damage response signaling and induces apoptosis. OSGEP and TP53RK molecularly interact and co-localize with the actin-regulating ARP2/3 complex. Furthermore, knockdown of OSGEP and TP53RK induces defects of the actin cytoskeleton and reduces migration rate of human podocytes, an established intermediate phenotype of SRNS. We thus identify 4 novel monogenic causes of GAMOS, describe the first link between KEOPS function and human disease, and delineate potential pathogenic mechanisms.

Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease cases. A mutation in 1 of over 40 monogenic genes can be detected in approximately 30% of individuals with SRNS whose symptoms manifest before 25 years of age. However, in many patients, the genetic etiology remains unknown. Here, we have performed whole exome sequencing to identify recessive causes of SRNS. In 7 families with SRNS and facultative ichthyosis, adrenal insufficiency, immunodeficiency, and neurological defects, we identified 9 different recessive mutations in SGPL1, which encodes sphingosine-1-phosphate (S1P) lyase. All mutations resulted in reduced or absent SGPL1 protein and/or enzyme activity. Overexpression of cDNA representing SGPL1 mutations resulted in subcellular mislocalization of SGPL1. Furthermore, expression of WT human SGPL1 rescued growth of SGPL1-deficient dpl1. yeast strains, whereas expression of disease-associated variants did not. Immunofluorescence revealed SGPL1 expression in mouse podocytes and mesangial cells. Knockdown of Sgpl1 in rat mesangial cells inhibited cell migration, which was partially rescued by VPC23109, an S1P receptor antagonist. In Drosophila, Sply mutants, which lack SGPL1, displayed a phenotype reminiscent of nephrotic syndrome in nephrocytes. WT Sply, but not the disease-associated variants, rescued this phenotype. Together, these results indicate that SGPL1 mutations cause a syndromic form of SRNS.

PubMed ID: 29058690, Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of chronic kidney disease. Here, we identified recessive mutations in the gene encoding the actin-binding protein advillin (AVIL) in 3 unrelated families with SRNS. While all AVIL mutations resulted in a marked loss of its actin-bundling ability, truncation of AVIL also disrupted colocalization with F-actin, thereby leading to impaired actin binding and severing. Additionally, AVIL colocalized and interacted with the phospholipase enzyme PLCE1 and with the ARP2/3 actin-modulating complex. Knockdown of AVIL in human podocytes reduced actin stress fibers at the cell periphery, prevented recruitment of PLCE1 to the ARP3-rich lamellipodia, blocked EGF-induced generation of diacylglycerol (DAG) by PLCE1, and attenuated the podocyte migration rate (PMR). These effects were reversed by overexpression of WT AVIL but not by overexpression of any of the 3 patient-derived AVIL mutants. The PMR was increased by overexpression of WT Avil or PLCE1, or by EGF stimulation; however, this increased PMR was ameliorated by inhibition of the ARP2/3 complex, indicating that ARP-dependent lamellipodia formation occurs downstream of AVIL and PLCE1 function. Together, these results delineate a comprehensive pathogenic axis of SRNS that integrates loss of AVIL function with alterations in the action of PLCE1, an established SRNS protein., VE 196/1-1, HE 7456/1-1, Jo 1324/1-1 U.S. Public Health Service: DK-56338 National Institutes of Health: DK076683 National Institute of Diabetes and Digestive and Kidney Diseases: DK-98120 National Research Foundation of Korea, NRF: 2015R1D1A1A01056685 Department of Science and Technology, Government of Kerala NAS LPDS-2015-07 Fudan University, We are grateful to the families and study participants for their contributions. We thank the Yale Center for Mendelian Genomics (U54HG006504) for WES analysis. FH is a William E. Harmon Professor of Pediatrics. This research was supported by the NIH (DK076683, to FH); the Young Scholars Program of Children’s Hospital of Fudan University (to JR); Basic Science Research Program through the National Research Foundation of Korea 2015R1D1A1A01056685 (to HYG); DFG fellowships (VE 196/1-1, to ATvdV; Jo 1324/1-1, to TJS; and HE 7456/1-1, to TH); the German National Academy of Sciences Leopoldina (LPDS-2015-07, to EW); the Egyptian Group for Orphan Renal Diseases (EGORD) (to NAS); the Department of Science and Technology, Government of India (DST-SERB, to MAJ); the National Institute of Diabetes and Digestive and Kidney Diseases (DK-98120, to SK); and the Public Health Service (DK-56338, to SK).

A modern approach of conjugate problem formulation currently widely used in heat transfer theory and applications is applied to simulate combustion–acoustic interaction process. The term conjugate corresponds to problems when solution domain consists of two or more subdomains with different properties and/or with phenomena described by different type of differential equations. In heat transfer, such subdomains are usually a fluid and a body or two fluids separated by solid. Similarly in combustion, such subdomains are fresh and burnt gases divided by a flame. As an example, the effect of flame location and burnt/fresh gases temperature ratio on combustion stability is investigated. It is assumed that forced oscillations are imposed on an existing in a tube flow, and stability of final oscillations at different flame locations and temperature ratios is studied. The well-known simple one-dimensional approach is improved using a physically founded, more reliable combustion model and an alternative method of solution based on strict mathematical formulation as a boundary-value problem similar to that applied in conjugate heat transfer theory. The mathematical development leads to a system of two integro-differential equations determining final velocity and pressure amplitudes at the flame. Analysis of an exact solution of this system gives the domains of similarity parameter defining time lags of the imposed forced oscillations that theoretically provide stability of the final oscillations. The stability pattern shows that the value of time lag decreases with increasing both parameters flame distance from the tube entrance and burnt/fresh temperature ratio.

Nucleoporins are essential components of the nuclear pore complex (NPC). Only a few diseases have been attributed to NPC dysfunction. Steroid-resistant nephrotic syndrome (SRNS), a frequent cause of chronic kidney disease, is caused by dysfunction of glomerular podocytes. Here we identify in eight families with SRNS mutations in NUP93, its interaction partner NUP205 or XPO5 (encoding exportin 5) as hitherto unrecognized monogenic causes of SRNS. NUP93 mutations caused disrupted NPC assembly. NUP93 knockdown reduced the presence of NUP205 in the NPC, and, reciprocally, a NUP205 alteration abrogated NUP93 interaction. We demonstrate that NUP93 and exportin 5 interact with the signaling protein SMAD4 and that NUP93 mutations abrogated interaction with SMAD4. Notably, NUP93 mutations interfered with BMP7-induced SMAD transcriptional reporter activity. We hereby demonstrate that mutations of NUP genes cause a distinct renal disease and identify aberrant SMAD signaling as a new disease mechanism of SRNS, opening a potential new avenue for treatment.