Project description:Identification of tear fluid biomarkers may offer a non-invasive strategy for detecting diabetic patients with increased risk of developing diabetic retinopathy (DR) or increased disease progression, thus helping both improving diagnostic accuracy and understanding the pathophysiology of the disease. The goal of this study was to characterize the proteomic profile of human tear fluid and examine changes in proteins expression in different stages of diabetic retinopathy.
Project description:Diabetic retinopathy is one of the leading causes of blindness in diabetic patients. Emerging evidence suggests that retinal neurodegeneration is an early event in the pathogenesis of diabetic retinopathy, but the underlying causes of neuronal loss are unknown. To unravel potential mechanisms underlying early retinal neurodegeneration in diabetic retinopathy, a gene expression profiling study was undertaken to compare the gene expression in retinas of 8-week db/db diabetic mice with that of lean non-diabetic littermates. Retinas were obtained from 8-week db/db diabetic mice and age-matched lean non-diabetic controls. Total RNA was extracted and processed for being hybridized onto affymetrix DNA microarrays.
Project description:The goal of the study was to identify genes whose aberrant expression can contribute to diabetic retinopathy. We determined differential response in gene expression to high glucose in lymphoblastoid cell lines derived from matched type 1 diabetic individuals with and without retinopathy. Those genes exhibiting the largest difference in glucose response between diabetic subjects with and without retinopathy were assessed for association to diabetic retinopathy utilizing genotype data from a meta-genome-wide association study. All genetic variants associated with gene expression (expression QTLs; eQTLs) of the glucose response genes were tested for association with diabetic retinopathy. We detected an enrichment of the glucose response gene eQTLs among small association p-values for diabetic retinopathy. Among these, we identified FLCN as a susceptibility gene for diabetic retinopathy. Expression of FLCN in response to glucose is greater in individuals with diabetic retinopathy compared to diabetic individuals without retinopathy. Three large, independent cohorts of diabetic individuals revealed an enhanced association of FLCN eQTL to diabetic retinopathy. Mendelian randomization confirmed a direct positive effect of increased FLCN expression on retinopathy in diabetic individuals. Together, our studies integrating genetic association and gene expression implicate FLCN as a disease gene in diabetic retinopathy.
Project description:A sensitive assay to identify biomarkers that can accurately diagnose the onset of breast cancer using non-invasively collected clinical specimens is ideal for early detection. In this study, we have conducted a prospective sample collection and retrospective blinded validation (PRoBE design) to evaluate the performance and translational utilities of salivary transcriptomic and proteomic biomarkers for the non-invasive detection of breast cancer. The Affymetrix HG U133 Plus 2.0 Array and 2D-DIGE were used to profile transcriptomes and proteomes in saliva supernatants respectively. Significant variations of salivary transcriptomic and proteomic profiles were observed between breast cancer patients and healthy controls. Eleven transcriptomic biomarker candidates and two proteomic biomarker candidates were selected for a preclinical validation using an independent sample set. Transcriptomic biomarkers were validated by RT-qPCR and proteomic biomarkers were validated by quantitative protein immunoblot. Eight mRNA biomarkers and one protein biomarker have been validated for breast cancer detection, yielding ROC-plot AUC values between 0.665 and 0.959. This report provides proof of concept of salivary biomarkers for the non-invasive detection of breast cancer. The salivary biomarkersâ discriminatory power paves the way for a PRoBE-design definitive validation study. Keywords: Salivary biomarker, Breast cancer, Early detection, Salivary transcriptome, Salivary proteome This study, which was approved by the UCLA and Cedars-Sinai Medical Center Institutional Review Boards (#06-07-043 and #3870, respectively), started sample collection in February 2007. The sample collection followed the PRoBE principle (prospective specimen collection). The saliva bank for breast cancer project at the UCLA Dental Research Institute in collaboration with Cedars Sinai Medical Center has collected 200 saliva samples since 2007 with all subjects recruited from the Saul and Joyce Brandman Breast Cancer Center. Of these, 113 samples, including 41 breast cancer patients and 72 healthy control individuals, were selected for the discovery and validation phase of this study. Inclusion criteria of cancer patients consisted of a confirmed diagnosis of breast cancer. Exclusion criteria of cancer patients included therapy/surgery and/or a diagnosis of other malignancies within 5 years prior to saliva collection. Exclusion criteria of control patients included a diagnosis of any malignancies within 5 years prior to saliva collection. Written informed consents and questionnaire data sheets were obtained from all patients who agreed to serve as saliva donors. Unstimulated saliva samples were consistently collected, stabilized, and preserved as previously described. The sample supernatants were reserved at -80 C prior to assay. This study consisted of a discovery phase, followed by an independent preclinical validation phase. Of the 113 samples, 10 breast cancer samples and 10 healthy control samples were chosen for the discovery phase. All breast cancer cases are invasive ductal carcinoma (IDC), the most common type of breast cancer. Biomarkers identified from the discovery studies were first verified using the discovery sample set. An independent sample set, including 31 breast cancer patients and 62 healthy control subjects, was used for the biomarker validation phase.
Project description:The aim of this study was to identify proteomic alterations associated with functional dysregulation of the retina with diabetes that could eventually be used as surrogate endpoints in preclinical drug testing studies. A multi-modal approach of antibody (Luminex)-, electrophoresis (2-DIGE)-, and LC-MS (iTRAQ)-based quantitation methods was used to provide broad coverage of the retinal proteome. Transcriptional profiling through microarray analysis was also included to increase coverage and provide insight into potential regulation of protein expression changes at the mRNA level. The different technologies proved complementary, with limited coverage overlap between methods. Diabetes was induced in Sprague-Dawley male rats (Charles River Laboratories, Wilmington, MA) by intraperitoneal injection of 65 mg/kg streptozotocin (STZ) (Sigma-Aldrich, St. Louis, MO) in 10mM sodium citrate pH 4.5 vehicle. Control rats were injected with an equal dose of vehicle only. Rats had free access to food and water, and were maintained on a 12 hour light/dark cycle. Blood glucose level and body weight were measured 6 days post-STZ or vehicle injection, and biweekly throughout the experiment. Only rats with blood glucose levels >250 mg/dL at the time of the original test and throughout the experiment were included in the diabetic groups. At the time of retina harvest, rats were given a lethal dose of pentobarbital, 100 mg/kg, (Ovation Pharmaceuticals Inc., Deerfield, IL) by intraperitoneal injection and sacrificed by decapitation. Retinas were rapidly excised snap- frozen in liquid nitrogen for subsequent experimentation.
Project description:The aim of this study was to identify proteomic alterations associated with functional dysregulation of the retina with diabetes that could eventually be used as surrogate endpoints in preclinical drug testing studies. A multi-modal approach of antibody (Luminex)-, electrophoresis (2-DIGE)-, and LC-MS (iTRAQ)-based quantitation methods was used to provide broad coverage of the retinal proteome. Transcriptional profiling through microarray analysis was also included to increase coverage and provide insight into potential regulation of protein expression changes at the mRNA level. The different technologies proved complementary, with limited coverage overlap between methods.
Project description:Diabetic retinopathy (DR) is a common microvascular complication that may cause severe visual impairment and blindness in patients with type 2 diabetes mellitus (T2DM). Early detection of DR will provide opportunities for more treatment options and better control of disease progression. Effective biomarkers, which are not currently available, may improve clinical outcomes through precise diagnosis and prognosis. We sought to develop a non-invasive diagnostic approach for diabetic retinopathy among type 2 diabetes mellitus based on 5-hydroxymethylcytosines (5hmC), an emerging epigenetic marker, in circulating cell-free DNA (cfDNA)