A genome-wide DNA microsatellite association screen to identify chromosomal regions harboring candidate genes in diabetic nephropathy

In an effort to accelerate the identification of susceptibility genes in diabetic nephropathy, the first genome-wide fluorescence-based DNA microsatellite (n=6000) association screen was performed, using pools of genomic DNA derived from Irish patients with (cases; n=200) and without (controls; n=200) type 1 diabetic nephropathy. Allele image profiles were generated for 5353 (89.2%) microsatellite markers for both case and control pools. Allele counts (estimated from allele image profiles) were compared in case versus control groups, and empirical P values were generated. Markers then were ranked on the basis of their empirical P values (lowest to highest). Repeat PCR amplification and electrophoresis of pooled samples were performed systematically on ranked markers until the 50 most associated markers with consistent results were identified. DNA samples that composed the pools then were genotyped individually for these markers. Two markers on chromosome 10, D10S558 (Pcorrected=0.005) and D10S1435 (Pcorrected=0.016), revealed statistically significant associations with diabetic nephropathy. An additional four markers (D6S281, D4S2937, D2S291, and D17S515) also are worthy of further investigation. Relevant functional candidate genes have been identified in the vicinity of these markers, demonstrating the feasibility of low-resolution genome-wide microsatellite association screening to identify possible candidate genes for diabetic nephropathy.     

Systems biology-based approaches to summarize and identify novel genes and pathways associated with acute and chronic postsurgical pain

Study objectiveTo employ systems biology–based machine learning to identify biologic processes over-represented with genetic variants (gene enrichment) implicated in post-surgical pain.DesignInformed systems biology based integrative computational analyses.SettingPediatric research and teaching institution.InterventionsPubmed search (01/01/2001–10/31/2017) was performed to identify “training” genes associated with postoperative pain in humans. Candidate genes were identified and prioritized using Toppgene suite, based on functional enrichment using several gene ontology annotations, and curated gene sets associated with mouse phenotype–knockout studies.MeasurementsComputationally top-ranked candidate genes and literature-curated genes were included in pathway enrichment analyses. Hierarchical clustering was used to visualize select functional enrichment results between the two phenotypes.Main resultsLiterature review identified 38 training genes associated with postoperative pain and 31 with CPSP. We identified 2610 prioritized novel candidate genes likely associated with acute and chronic postsurgical pain, the top 10th percentile jointly enriched (p 0.05; Benjamini-Hochberg correction) several pathways, topmost being cAMP response element-binding protein and ion channel pathways. Heat maps demonstrated enrichment of inflammatory/drug metabolism processes in acute postoperative pain and immune mechanisms in CPSP.ConclusionHigh interindividual variability in pain responses immediately after surgery and risk for CPSP suggests genetic susceptibility. Lack of large homogenous sample sizes have led to underpowered genetic association studies. Systems biology can be leveraged to integrate genetic-level data with biologic processes to generate prioritized candidate gene lists and understand novel biological pathways involved in acute postoperative pain and CPSP. Such data would be key to informing future polygenic studies with targeted genome wide profiling. This study demonstrates the utility of functional annotation - based prioritization and enrichment approaches and identifies novel genes and unique/shared biological processes involved in acute and chronic postoperative pain. Results provide framework for future targeted genetic profiling of CPSP risk, to enable preventive and therapeutic approaches.     

LRP4 association to bone properties and fracture and interaction with genes in the Wnt- and BMP signaling pathways

Osteoporosis is a common complex disorder in postmenopausal women leading to changes in the micro-architecture of bone and increased risk of fracture. Members of the low-density lipoprotein receptor-related protein (LRP) gene family regulates the development and physiology of bone through the Wnt/β-catenin (Wnt) pathway that in turn cross-talks with the bone morphogenetic protein (BMP) pathway. In two cohorts of Swedish women: OPRA (n=1002; age 75 years) and PEAK-25 (n=1005; age 25 years), eleven single nucleotide polymorphisms (SNPs) from Wnt pathway genes (LRP4; LRP5; G protein-coupled receptor 177, GPR177) were analyzed for association with Bone Mineral Density (BMD), rate of bone loss, hip geometry, quantitative ultrasound and fracture. Additionally, interaction of LRP4 with LRP5, GPR177 and BMP2 were analyzed. LRP4 (rs6485702) was associated with higher total body (TB) and lumbar spine (LS) BMD in the PEAK-25 cohort (p=0.006 and 0.005 respectively), and interaction was observed with LRP5 (p=0.007) and BMP2 (p=0.004) for TB BMD. LRP4 also showed significant interaction with LRP5 for femoral neck (FN) and LS BMD in this cohort. In the OPRA cohort, LRP4 polymorphisms were associated with significantly lower fracture incidence overall (p=0.008-0.001) and fewer hip fractures (rs3816614, p=0.006). Significant interaction in the OPRA cohort was observed for LRP4 with BMP2 and GPR177 for FN BMD as well as for rate of bone loss at TB and FN (p=0.007-0.0001). In conclusion, LRP4 and interaction between LRP4 and genes in the Wnt and BMP signaling pathways modulate bone phenotypes including peak bone mass and fracture, the clinical endpoint of osteoporosis.     

进展期胃癌SOX新辅助化疗敏感性相关基因及信号通路的生物信息学分析

目的:探讨与进展期胃癌对替吉奥胶囊联合奥沙利铂(SOX)新辅助化疗敏感性有关的基因及信号通路。方法:收集15例III期胃癌患者术后标本,其中6例SOX新辅助化疗后缓解(缓解组)、6例SOX新辅助化疗后未缓解(未缓解组),3例未行新辅助化疗(未化疗组),在用高通量基因芯片法检测各组标本基因表达谱后,以DNA损伤修复和叶酸代谢方面为重点分析对象,用系统性生物信息学技术筛选出差异基因,并通过KEGG来解释每个差异表达基因所在通路。结果:3组标本的基因表达谱存在明显差异。缓解组与未缓解组间的差异基因主要集中在细胞因子相互作用和NK细胞介导的细胞毒性作用通路上。与未缓解组比较,缓解组与DNA损伤修复相关的3个基因(HUS1、RECQL5、XRCC4)明显上调和1个基因(GADD45G)明显下调;3组间在叶酸代谢方面未找到任何差异基因。结论:影响进展期胃癌SOX新辅助化疗敏感性的基因可能与免疫信号传导有关,相关的基因检测对评估胃癌SOX新辅助化疗效果有一定的意义。     

Keloid fibroblast responsiveness to epidermal growth factor and activation of downstream intracellular signaling pathways.

Keloids, which overgrow the boundaries of the original injury, represent aberrations in the fundamental process of wound healing that include over-abundant cell in-migration, cell proliferation, and inflammation, as well as increased extracellular matrix synthesis and defective remodeling. To understand the key events that result in the formation of these abnormal scars would open new avenues for better understanding of excessive repair, and might provide new therapeutic options. We examined epidermal growth factor receptor (EGFR)-induced cell motility in keloid fibroblasts, as this receptor initiates cell migration during normal wound repair. We show that keloid fibroblasts respond to EGF-induced cell migration but the response is somewhat diminished compared to normal adult fibroblasts (approximately 30% reduced); the mitogenic response was similarly blunted (approximately 5% reduced). Keloid fibroblasts express near normal levels of EGFR (82%), but show a much more attenuated activation of EGFR itself and the motility-associated phospholipase C-gamma. This was reflected in part by rapid loss of EGFR upon exposure to EGF. Interestingly, while extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK-MAPK) activation was relatively robust in keloid fibroblasts, the downstream triggering of the motility-associated calpain activity was blunted. This was reflected by high cell-substratum adhesiveness in the keloid fibroblasts. Thus, the blunted migratory response to EGF noted in keloid fibroblasts appears due to limited activation of two important biochemical switches for cell motility.     

A patient with Bartter syndrome accompanying severe growth hormone deficiency and focal segmental glomerulosclerosis

Bartter syndrome is a rare autosomal recessive, salt-losing disorder characterized by hypokalemic hypochloremic metabolic alkalosis. A 10-year-old boy had severe growth retardation (height standard deviation score −8.15). He had a thin, triangular face, prominent ears and forehead, and big eyes. Megacystis, bilateral hydroureteronephrosis, and residual urine were detected in ultrasonography, but there was no vesicoureteral reflux. Lumbosacral magnetic resonance (MR) showed posterior disc bulging at L4–5. Serum sodium and chloride levels were normal, but mild hypokalemia was overlooked initially. During follow-up, hypokalemic hypochloremic metabolic alkalosis developed, with high urinary chloride and potassium excretion (52 and 43 mEq/L, respectively). The patient, with renal salt loss, was thought to have classic Bartter syndrome due to absence of nephrocalcinosis, presence of persistent hypercalciuria and sensorineural deafness, and presence of relatively mild clinical and laboratory findings, except polyuria initially. The child was treated with indomethacin, spironolactone, and oral potassium in addition to growth hormone (GH). During treatment, he had considerable increase in weight and height compared with the period of GH therapy only. We present this case because, although growth retardation is a major feature of Bartter syndrome, associated GH deficiency is rarely reported in the literature. Diagnosis of Bartter syndrome was made later, as our patient was followed for megacystis and megaureter secondary to the neurogenic bladder and GH deficiency initially; and proteinuria associated with focal segmental glomerulosclerosis responded to treatment for Bartter syndrome.     

Clarification of signaling pathways mediated by insulin and insulin-like growth factor I receptors in fibroblasts from patients with specific defect in insulin receptor

Receptor binding and biological action of insulin and insulin-like growth factor I (IGF-I) were studied in fibroblasts from a patient with leprechaunism and a patient with type A syndrome of insulin resistance. Insulin binding was reduced to 18.8 and 27.7% of control value, respectively. In contrast, IGF-I binding was normal in both patients. In competitive binding studies, IGF-I had 0.2% of the ability of insulin to compete with 125I-labeled insulin binding, and insulin had 0.1% of the ability of IGF-I to compete with 125I-labeled IGF-I binding in control subjects and patient fibroblasts. The dose-response curves of insulin stimulation assessed by glucose incorporation and alpha-aminoisobutyric acid uptake showed normal responsiveness, and ED50 was significantly shifted to the right in fibroblasts from both patients. However, normal responsiveness and sensitivity were observed in thymidine incorporation studies. For IGF-I, dose-response curves of glucose incorporation, alpha-aminoisobutyric acid uptake, and thymidine incorporation were all normal in both patients. These results indicate that 1) the defect is specific to the insulin-receptor binding in these patients, 2) insulin and IGF-I activate glucose incorporation and alpha-aminoisobutyric acid uptake mainly through their own specific receptors, but 3) the IGF-I receptor appears to have a more important role in stimulating thymidine incorporation than the insulin receptor in physiological condition or, alternatively, an unknown postreceptor process with cascade signal transmission may overcome the decreased insulin-receptor binding to produce a normal dose-response curve.     

A novel CLCN5 mutation in a boy with Bartter-like syndrome and partial growth hormone deficiency

Dent disease is an X-linked recessive disorder affecting the proximal tubule and is characterized by low-molecular-weight proteinuria (LMWP), hypercalciuria, nephrocalcinosis/nephrolithiasis with a variable number of features of Fanconi syndrome. It is most often associated with mutations in CLCN5, which encodes the endosomal electrogenic chloride/proton exchanger ClC-5. Renal acidification abnormalities are only rarely seen in Dent disease, whereas the hypokalemic metabolic alkalosis associated with hyperreninemic hyperaldosteronism (Bartter-like syndrome) has been reported in only one patient so far. We report on a 5-year-old boy with Dent disease caused by mutation in CLCN5 gene, c.1073G>A, who presented with hypokalemic metabolic alkalosis and hyperreninemic hyperaldosteronism persisting over the entire follow-up. No mutations were found in NKCC2, ROMK, NCCT, or ClC-Kb genes. In addition, the patient exhibited growth failure associated with partial growth hormone (GH) deficiency. Coexistence of Bartter-like syndrome features with LMWP should prompt a clinician to search for Dent disease. The Bartter syndrome phenotype seen in Dent disease patients may represent a distinct form of Bartter syndrome, the exact mechanism of which has yet to be fully elucidated. Growth delay that persists in spite of appropriate therapy should raise suspicion of other causes, such as GH deficiency.     

Low bone mineral density in adults with previous hypothalamic-pituitary tumors: Correlations with serum growth hormone responses to GH-releasing hormone,insulin-like growth factor I,and IGF binding protein 3

Summary The adverse consequences of growth hormone (GH) deficiency (GHD) on bone growth in children is well described. Whether adult GHD is associated with bone loss is unknown. We evaluated 14 patients with hypothalamicpituitary tumors (HPT) acquired during adulthood (5 men, 9 women; age=48.1±4.6 years; BMI=28.8±1.7) and 14 age-, sex-, and weight-matched controls. Nine HPT patients were receiving gonadal steroid replacement therapy for a mean of 11 years. All subjects had basal IGF-I and IGFBP-3 levels prior to testing with GH-releasing hormone [1 g/kg IV bolus; responses expressed as maximum percentage increase above baseline (PERGH)]. Bone mineral density (BMD) of the spine, hip, and total body were measured by dual-energy X-ray absorptiometry. Mean BMD Z-scores of the HPT patients were significantly lower in the femoral neck, Ward's triangle, and trochanter than in controls (all P<0.05). Mean total body BMD (g/cm²) was also lower in the patient group (1.04±0.03 versus 1.13±0.03, P<0.05). For the subgroup of HPT patients receiving conventional gonadal steroids, mean BMD Z-scores of the lumbar spine also were significantly lower than controls (-1.84±0.43 versus -0.57±0.46, P<0.05). PERGH and IGF-l were correlated with Z-scores of the femoral neck (r=0.47, P<0.01; r=0.45, P<0.01) and Ward's triangle (r=0.47, P<0.01; r=0.41, P<0.05). These results indicate that adults with previous HPTs have significantly lower spine and hip BMD compared with healthy controls, regardless of gonadal steroid therapy, and that this premature bone loss is associated with relative GHD. IGF-I and PERGH measurements might be useful markers to identify such patients at risk for reduced BMD.     

Bone size and density measurements in prepubertal children with Turner syndrome prior to growth hormone therapy

Summary  

Using computed tomography (CT), we found the decreases in bone size of vertebrae and femur, cortical bone area (CBA) of femur and bone density (BD) of vertebrae in prepubertal female with Turner syndrome (TS) compared to those of controls.     

Renal size and function in patients with neuropathic bladder due to myelomeningocele: the role of growth hormone

PURPOSE: Patients with spina bifida have smaller kidneys than healthy individuals. We evaluated the correlation between small size and decreased renal function, and the possible role of growth hormone deficiency. MATERIALS AND METHODS: A total of 54 patients (mean age 11.5 years, median 11, standard deviation +/- 4.52) were healthy except for neuropathic bladder due to spina bifida. Renal function was evaluated with mercaptoacetyltriglycine renal scintigraphy and creatinine clearance. Renal anatomy was evaluated with renal ultrasound and voiding cystourethrography. Serum insulin-like growth factor-1 (IGF-1) levels were measured in all patients with immunoradiometric assay. Renal measurements in our patients were compared using the Sutherland nomogram. RESULTS: A total of 22 patients (41%) had smaller kidneys than normal subjects and 31 appeared to have creatinine clearance values lower than 120 ml per minute per 1.73 m2. The statistical comparison between kidney size and creatinine clearance was significant (p <0.05, r = 0.381). Scintigraphic data showed total effective renal plasma flow less than 568 ml per minute per 1.73 m2 body surface area (normal mean value for age). Comparison between effective renal plasma flow and creatinine clearance was significant (p <0.05, r = 0.31). Serum levels of IGF-1 were normal for age in all patients (mean 332.06 ng/ml, median 303.4, range 39.4 to 732.3). CONCLUSIONS: The kidneys are smaller in patients with spina bifida than in healthy subjects when compared using the Sutherland nomogram. There is a significant correlation between smaller renal length and decreased renal function in all patients, even in those who are healthy except for neurogenic bladder secondary to spina bifida. IGF-1 levels were normal for age, and, therefore, these patients had no growth hormone deficiency. These findings call into question the hypothesis that growth hormone deficiency contributes to smaller kidney size. Other hypotheses can be suggested, such as a defect of embryological growth secondary to malformation, or the result of a defect in homocysteine-methionine metabolism.     

Response of insulin, glucagon and growth hormone to arginine infusion in patients with chronic renal failure.

To determine whether glucose intolerance in patients with chronic renal failure could improve by hemodialysis, the effects of arginine infusion on the concentration of blood sugar, insulin, glucagon, growth hormone were examined in healthy volunteers, undialyzed and dialyzed patients with chronic renal failure. Plasma concentrations of sugar and hormones in undialyzed and dialyzed patients responded similarly to arginine infusion. While blood samples were collected at 30, 45, 60, 90, 120 and 180 min after beginning infusion of arginine, the concentrations of sugar and hormones in both patients had no statistically significant differences. However, plasma concentrations of growth hormone in both patients 180 min after beginning of arginine infusion gave statistically significant differences. In the present study, the results suggest that hemodialysis might not improve the glucose tolerance in the patients with chronic renal failure.     

Polymorphisms in genes related to activation or detoxification of carcinogens might interact with smoking to increase renal cancer risk: results from The Netherlands Cohort Study on diet and cancer

Metabolic gene polymorphisms have previously been suggested as risk factors for renal cell carcinoma (RCC). These polymorphisms are involved in activation or detoxification of carcinogens in cigarette smoke which is another RCC risk factor. We evaluated gene–environment interactions between CYP1A1, GSTμ1 and smoking in a large population-based RCC case group. The Netherlands Cohort Study on diet and cancer (NLCS) comprises 120,852 persons who completed a questionnaire on smoking and other risk factors at baseline. After 11.3 years of follow-up, 337 incident RCC cases were identified. DNA was collected for 245 cases. In a case-only analysis, interaction-odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using logistic regression. We observed a moderate, not statistically significant, interaction between current smoking and CYP1A1*2C (OR 1.42; 95% CI 0.70–2.89) and GSTμ1 null (OR 1.35; 95% CI 0.65–2.79). For current smokers with both a variant (heterozygous or homozygous) in CYP1A1 and GSTμ1 null, risk was also increased (OR 1.63; 95% CI 0.63–4.24). No interaction was observed between ever smokers, smoking duration (increments of 10 smoking years) or amount (increments of 5 cigarettes/day) and CYP1A or GSTμ1. Our results show a modest trend towards a statistically significant gene–environment interaction between CYP1A1, GSTμ1 and smoking in RCC. This could indicate that RCC risk among smokers might be more increased with the CYP1A1*2C genotype, GSTμ1 null, or both a CYP1A1 variant and GSTμ1 null. The Dutch Kidney Foundation (grant number C99.1863) and the Netherlands Cancer Society financially supported this study.     

Potentiation of the inhibitory effect of growth hormone-releasing hormone antagonists on PC-3 human prostate cancer by bombesin antagonists indicative of interference with both IGF and EGF pathways

BACKGROUND: In view of the involvement of various neuropeptides and growth factors in the progression of androgen-independent prostate cancer, we investigated the effects of antagonists of growth hormone-releasing hormone (GHRH) alone or in combination with an antagonist of bombesin/gastrin-releasing peptide (BN/GRP) on PC-3 human prostate cancers. METHODS: Nude mice implanted with PC-3 tumors received GHRH antagonists MZ-5-156 or JV-1-38, each at 20 microgram/day s.c. In experiment 2, treatment consisted of daily injections of JV-1-38 (20 microgram), BN/GRP antagonist RC-3940-II (10 microgram), or a combination of JV-1-38 and RC-3940-II. Serum IGF-I levels, expression of mRNA for IGF-II, and characteristics of BN/GRP and EGF receptors in tumor tissue were investigated. RESULTS: JV-1-38 induced a greater inhibition of tumor growth and suppression of IGF-II mRNA than MZ-5-156, both compounds causing a similar decrease in serum IGF-I. In experiment 2, JV-1-38 and RC-3940-II produced a comparable reduction in tumor volume (65% and 61%, respectively), but a combination of both antagonists augmented tumor inhibition to 75%. Combined treatment with JV-1-38 and RC-3940-II also led to a greater suppression of IGF-II mRNA (92%), as compared with JV-1-38 (72%) or RC-3940-II (77%). Serum IGF-I concentration was lowered only in mice treated with JV-1-38, while the downregulation of BN/GRP and EGF receptors was specific for groups receiving RC-3940-II. CONCLUSIONS: The inhibitory effects of GHRH antagonists on PC-3 human androgen-independent prostate cancer can be potentiated by concomitant use of BN/GRP antagonists. The combination of both types of analogs apparently interferes with both IGF and bombesin/EGF pathways, and might be clinically useful for the management of androgen-independent prostate cancer.