The role of liver receptor homologue-­1 (LRH-­1) in colorectal cancer

The development of colorectal cancer (CRC) occurs sequentially through the accumulation of genetic changes, or mutations, resulting in unrestrained cellular proliferation and survival. The genetic changes leading to CRC are well defined, with aberrant activation of the Wnt signalling pathway and loss of the tumour suppressor p53 playing key roles. This project aimed to investigate the role of the orphan nuclear receptor liver receptor homologue-1 (LRH-1) in the development of CRC. Previous work in this laboratory identified LRH-1 as an important mediator of the estrogen response in breast cancer cells. LRH-1 has also been implicated in the development of CRC, where it promotes cell cycle progression and synergises with β-catenin. Here I provide evidence for novel mutations in the DNA binding domain of LRH-1 in CRC. I found that CRC-associated LRH-1 mutations affect its ability to bind LRH-1 response elements. To better define the mechanisms of LRH-1 action in CRC, gene expression microarray analyses were performed in two CRC cell lines following siRNA-mediated LRH-1 knockdown. Several previously undescribed candidate LRH-1-regulated genes were identified and validated. While I found no evidence for crosstalk between LRH-1 and the Wnt pathway in the CRC cell lines examined, pathway analyses coupled to gene expression profiling suggested a role for LRH-1 in p53 signalling. LRH-1 silencing was shown to be associated with growth inhibition and up-regulation of the cell cycle inhibitor p21 in CRC cells. This occurs in a p53-dependent manner and was not observed in cell lines where p53 is mutated or deleted. I further demonstrated LRH-1-mediated modulation of p53 activity at the p21 promoter. Collectively, this work demonstrates a novel role for LRH-1 in the suppression of p53 signalling in CRC tumours that retain wild-type p53, and identifies LRH-1 as an important prospective target for treatment of these tumours.Open Acces

Association Between APOL1 Genotypes and Risk of Cardiovascular Disease in MESA (Multi-Ethnic Study of Atherosclerosis).

BACKGROUND:APOL1 genetic variants confer an increased risk for kidney disease. Their associations with cardiovascular disease (CVD) are less certain. We aimed to compare the prevalence of subclinical CVD and incidence of atherosclerotic CVD and heart failure by APOL1 genotypes among self-identified black participants of MESA (Multi-Ethnic Study of Atherosclerosis). METHODS AND RESULTS:Cross-sectional associations of APOL1 genotypes (high-risk=2 alleles; low-risk=0 or 1 allele) with coronary artery calcification, carotid-intimal media thickness, and left ventricular mass were evaluated using logistic and linear regression. Longitudinal associations of APOL1 genotypes with incident myocardial infarction, stroke, coronary heart disease, and congestive heart failure were examined using Cox regression. We adjusted for African ancestry, age, and sex. We also evaluated whether hypertension or kidney function markers explained the observed associations. Among 1746 participants with APOL1 genotyping (mean age 62 years, 55% women, mean cystatin C-based estimated glomerular filtration rate 89 mL/min per 1.73 m2, 12% with albuminuria), 12% had the high-risk genotypes. We found no difference in prevalence or severity of coronary artery calcification, carotid-intimal media thickness, or left ventricular mass by APOL1 genotypes. The APOL1 high-risk group was 82% more likely to develop incident heart failure compared with the low-risk group (95% confidence interval, 1.01-3.28). Adjusting for hypertension (hazard ratio, 1.80; 95% confidence interval, 1.00-3.24) but not markers of kidney function (hazard ratio, 1.86; 95% confidence interval, 1.03-3.35) slightly attenuated this association. The APOL1 high-risk genotypes were not significantly associated with other clinical CVD outcomes. CONCLUSIONS:Among blacks without baseline CVD, the APOL1 high-risk variants may be associated with increased risk for incident heart failure but not subclinical CVD or incident clinical atherosclerotic CVD

Mapping functional transcription factor networks from gene expression data

A critical step in understanding how a genome functions is determining which transcription factors (TFs) regulate each gene. Accordingly, extensive effort has been devoted to mapping TF networks. In Saccharomyces cerevisiae, protein–DNA interactions have been identified for most TFs by ChIP-chip, and expression profiling has been done on strains deleted for most TFs. These studies revealed that there is little overlap between the genes whose promoters are bound by a TF and those whose expression changes when the TF is deleted, leaving us without a definitive TF network for any eukaryote and without an efficient method for mapping functional TF networks. This paper describes NetProphet, a novel algorithm that improves the efficiency of network mapping from gene expression data. NetProphet exploits a fundamental observation about the nature of TF networks: The response to disrupting or overexpressing a TF is strongest on its direct targets and dissipates rapidly as it propagates through the network. Using S. cerevisiae data, we show that NetProphet can predict thousands of direct, functional regulatory interactions, using only gene expression data. The targets that NetProphet predicts for a TF are at least as likely to have sites matching the TF's binding specificity as the targets implicated by ChIP. Unlike most ChIP targets, the NetProphet targets also show evidence of functional regulation. This suggests a surprising conclusion: The best way to begin mapping direct, functional TF-promoter interactions may not be by measuring binding. We also show that NetProphet yields new insights into the functions of several yeast TFs, including a well-studied TF, Cbf1, and a completely unstudied TF, Eds1

Persistent expression of chemokine and chemokine receptor RNAs at primary and latent sites of herpes simplex virus 1 infection

Inflammatory cytokines and infiltrating T cells are readily detected in herpes simplex virus (HSV) infected mouse cornea and trigeminal ganglia (TG) during the acute phase of infection, and certain cytokines continue to be expressed at lower levels in infected TG during the subsequent latent phase. Recent results have shown that HSV infection activates Toll-like receptor signaling. Thus, we hypothesized that chemokines may be broadly expressed at both primary sites and latent sites of HSV infection for prolonged periods of time. Real-time reverse transcriptase-polymrease chain reaction (RT-PCR) to quantify expression levels of transcripts encoding chemokines and their receptors in cornea and TG following corneal infection. RNAs encoding the inflammatory-type chemokine receptors CCR1, CCR2, CCR5, and CXCR3, which are highly expressed on activated T cells, macrophages and most immature dendritic cells (DC), and the more broadly expressed CCR7, were highly expressed and strongly induced in infected cornea and TG at 3 and 10 days postinfection (dpi). Elevated levels of these RNAs persisted in both cornea and TG during the latent phase at 30 dpi. RNAs for the broadly expressed CXCR4 receptor was induced at 30 dpi but less so at 3 and 10 dpi in both cornea and TG. Transcripts for CCR3 and CCR6, receptors that are not highly expressed on activated T cells or macrophages, also appeared to be induced during acute and latent phases; however, their very low expression levels were near the limit of our detection. RNAs encoding the CCR1 and CCR5 chemokine ligands MIP-1α, MIP-1β and RANTES, and the CCR2 ligand MCP-1 were also strongly induced and persisted in cornea and TG during the latent phase. These and other recent results argue that HSV antigens or DNA can stimulate expression of chemokines, perhaps through activation of Toll-like receptors, for long periods of time at both primary and latent sites of HSV infection. These chemokines recruit activated T cells and other immune cells, including DC, that express chemokine receptors to primary and secondary sites of infection. Prolonged activation of chemokine expression could provide mechanistic explanations for certain aspects of HSV biology and pathogenesis

The Association of Chronic Kidney Disease and Metabolic Syndrome with Incident Cardiovascular Events: Multiethnic Study of Atherosclerosis

Background. There is an association between chronic kidney disease (CKD) and metabolic syndrome (MetS). We examined the joint association of CKD and MetS with incident cardiovascular (CVD) events in the Multiethnic Study of Atherosclerosis (MESA) cohort. Methods. We analyzed 2,283 Caucasians, 363 Chinese, 1,449 African-Americans, and 1,068 Hispanics in the MESA cohort. CKD was defined by cystatin C estimated glomerular filtration rate ≤ 60 mL/min/1.73 m2 and MetS was defined by NCEP criteria. Cox proportional regression adjusting for age, ethnicity, gender, study site, education, income, smoking, alcohol use, physical activity, and total and LDL cholesterol was performed to assess the joint association of CKD and MetS with incident CVD events. Participants were divided into four groups by presence of CKD and/or MetS and compared to the group without CKD and MetS (CKD−/MetS−). Tests for additive and multiplicative interactions between CKD and MetS and prediction of incident CVD were performed. Results. During follow-up period of 5.5 years, 283 participants developed CVD. Multivariate Cox regression analysis demonstrated that CKD and MetS were independent predictors of CVD (hazard ratio, 2.02 for CKD, and 2.55 for MetS). When participants were compared to the CKD−/MetS− group, adjusted HR for the CKD+/MetS+ group was 5.56 (95% CI 3.72–8.12). There was no multiplicative interaction between CKD and MetS (P=0.2); however, there was presence of additive interaction. The relative excess risk for additive interaction (RERI) was 2.73, P=0.2, and the attributable portion (AP) was 0.49 (0.24–0.74). Conclusion. Our findings illustrate that the combination of CKD and MetS is a strong predictor of incident clinical cardiovascular events due to presence of additive interaction between CKD and MetS

Outcomes of Albumin Use in the Treatment of Acute Hepatorenal Disorders: A Single Center Experience

Intravenous albumin is recommended for hepatorenal disorders (HRD), but individuals who do not recover renal function may be at a high risk for pulmonary edema. We reviewed outcomes by the amount of albumin infused in 93 patients not receiving dialysis at admission but being treated with intravenous albumin for acute HRD at our institution. Absence of renal recovery was defined as no decrease in serum creatinine and requirement of dialysis during hospitalization, and partial renal recovery was defined as a decrease in serum creatinine but not to prehospitalization levels. Associations of clinical factors including total albumin infused, presence of renal recovery, and oliguria with the development of pulmonary edema during hospitalization were determined using logistic regression. Of the 93 patients, 20 patients had complete renal recovery, 17 patients had partial renal recovery, and 56 patients showed no renal recovery. Most patients received 300–600 g of albumin. Overall, 47.3% of patients developed pulmonary edema (n=44), but the risk was 75% in patients with oliguria on presentation and no renal recovery versus 17% in those with no oliguria and complete renal recovery (P<0.001). In the logistic regression model, oliguria (3.32; 95% confidence interval [CI]: 1.12, 9.81) and no renal recovery (3.38; 95% CI: 1.24, 9.16) were each associated with higher odds of pulmonary edema after adjustment for covariates. No association was noted between total albumin infused and pulmonary edema. In summary, absence of renal recovery and oliguria in patients with HRD receiving intravenous albumin is associated with a higher risk of pulmonary edema

Anti-Mullerian hormone inhibits initiation of primordial follicle growth in the mouse ovary

Recruitment of primordial follicles is essential for female fertility; however, the exact mechanisms regulating this process are largely unknown. Earlier studies using anti-Mullerian hormone (AMH)-deficient mice suggested that AMH is involved in the regulation of primordial follicle recruitment. We tested this hypothesis in a neonatal ovary culture system, in which ovaries from 2-d-old C57Bl/6J mice were cultured for 2 or 4 d in the absence or presence of AMH. Ovaries from 2-d-old mice contain multiple primordial follicles, some naked oocytes, and no follicles at later stages of development. We observed that in the cultured ovaries, either nontreated or AMH-treated, follicular development progressed to the same extent as in in vivo ovaries of comparable age, confirming the validity of our culture system. However, in the presence of AMH, cultured ovaries contained 40% fewer growing follicles compared with control ovaries. A similar reduction was found after 4 d of culture. Consistent with these findings, we noted lower inhibin alpha-subunit expression in AMH-treated ovaries compared with untreated ovaries. In contrast, expression of AMH ligand type II receptor and the expression of oocyte markers growth and differentiation factor 9 and zona pellucida protein 3 were not influenced by AMH. Based on the results, we suggest that AMH inhibits initiation of primordial follicle growth and therefore functions as an inhibitory growth factor in the ovary during these early stages of folliculogenesis

Vitamin D Levels are Associated with Liver Disease Severity in Patients with Cirrhosis

Vitamin D deficiency is common in advanced liver disease but its clinical significance remains controversial. The aim of this study was to examine the correlation of 25-hydryoxyvitamin D levels with liver disease severity and calcium levels in adults with cirrhosis. This cross-sectional study included 180 adults with cirrhosis enrolled in a clinical cohort study at a single university hospital. The mean age was 58.8 (±9.2) years, and cirrhosis was attributed to alcohol use in 27.2%, hepatitis C in 35.0%, non-alcoholic steatohepatitis in 27.2%, and both alcohol and hepatitis C in 10.6%. The median model for end-stage liver disease-sodium (MELD-Na) score was 12.0 (interquartile range 9.0–16.0), and mean serum albumin levels were 3.4 (±0.7) gm/dl. Median serum 25-hydroxyvitamin D levels were 28.0 (interquartile range 20–38) ng/mL, with 16 patients (8.9%) having levels <12 ng/ml and 43 (23.9%) with 25(OH)D levels <20 ng/ml. No correlation was noted between levels of 25-hydroxyvitamin D and albumin-corrected calcium in the total group and in groups stratified by vitamin D supplementation. In contrast, both serum albumin (r = 0.32; P < 0.001) and MELD-Na scores were significantly correlated with 25-hydroxyvitamin D levels (r = –0.29; P < 0.001). Correlations between 25-hydroxyvitamin D levels and serum albumin (r = −0.39; P < 0.001) and MELD-Na scores did not change substantially after excluding 67 patients receiving vitamin D supplementation (r = −0.33; P = 0.009). In conclusion, total 25-hydroxyvitamin D levels correlate inversely with liver disease severity in adults with cirrhosis

KDOQI US Commentary on the 2017 ACC/AHA Hypertension Guideline

Hypertension is a modifiable risk factor for cardiovascular morbidity and mortality and reduction of elevated blood pressure (BP) remains an important intervention for slowing kidney disease progression. Over the past decade, the most appropriate BP target for initiation and titration of BP-lowering medications has been an area of intense research and debate within the clinical community. In 2017, the American College of Cardiology and the American Heart Association (ACC/AHA) in conjunction with several other professional societies released new hypertension guidelines based on data from a systematic review of clinical trials and observational data. While many of the recommendations in the ACC/AHA hypertension guideline are relevant to nephrology practice, BP targets and management strategies for patients receiving dialysis are not discussed. This Kidney Disease Outcomes Quality Initiative (KDOQI) commentary focuses largely on recommendations from the ACC/AHA hypertension guidelines that are pertinent to individuals at risk of chronic kidney disease or with non–dialysis-dependent chronic kidney disease. This KDOQI commentary also includes a brief discussion of the consensus statement regarding hypertension diagnosis and management for adults receiving maintenance dialysis published by the European Renal and Cardiovascular Medicine Working Group of the European Renal Association–European Dialysis and Transplant Association (ERA-EDTA) and the Hypertension and the Kidney working group of the European Society of Hypertension. Overall, we support the vast majority of the ACC/AHA recommendations and highlight select areas in which best diagnosis and treatment options remain controversial