Brain Derived Neurotrophic Factor: A Foray Into Predicting Neonatal Outcomes In Premature Infants

The need to accurately predict the ability of a prematurely born infant to recover from hypoxia induced damage associated with prematurity is rooted in our need to develop better interventions, with fewer side-effects, with which to treat these complicated patients. Previous work done in murine models mimicking hypoxia induced damage and its neurological sequelae have suggested hypoxia induced factor-1alpha; (HIF-1alpha), and its downstream effector molecules, brain derived neurotrophic factor (BDNF) and stromal derived factor-1 (SDF-1), may play an integral role in protecting the developing brain from the deleterious effects of low O2. Moreover, a number of single nucleotide polymorphisms (SNPs) have been identified, which affect the expression of these proteins on an individual basis. To that end, we hypothesized that BDNF expression levels gathered from venous cord blood, and genetic analysis for the presence of the rs6265 and rs1801157 SNPs in the BDNF and SDF-1 genes could be used as biochemical and genetic biomarkers to predict short term neonatal outcomes in premature infants born at Yale New Haven Hospital. BDNF levels, determined by quantitative ELISA in 23 patients, and the presence of SNPs, determined in duplicate by restriction fragment length polymorphism assay and Sanger sequencing in 53 patients, were correlated with the development of a variety of neonatal outcomes. Our results indicated that although not statistically significant, the development of bronchopulmonary dysplasia, necrtotizing enterocolitis, and early onset neonatal sepsis (EONS) trended towards an association with lower cord blood BDNF levels (p-values \u3c0.10). Likewise, the presence of the rs6265 SNP appeared to be protective against the development of culture positive EONS (p \u3c 0.08), while the presence of rs1801157 SNP appeared to be protective against the development of clinical EONS. Taken together, these data suggest that while cord blood BDNF levels and the presence of the rs6265 and rs1801157 SNPs show potential as useful molecular and genetic biomarkers for predicting outcomes of premature infants, the association between these factors and neonatal outcomes is not strong enough for the number of patients examined in this study to provide conclusive results of the utility of these biomarkers in guiding clinical decision making. Consequently, further research of these, and other, biomarkers is necessary to better elucidate their usefulness

Networks of intergenic long-range enhancers and snpRNAs drive castration-resistant phenotype of prostate cancer and contribute to pathogenesis of multiple common human disorders

Biological and mechanistic relevance of intergenic disease-associated genetic loci (IDAGL) containing highly statistically significant disease-linked SNPs remains unknown. Here we present the experimental and clinical evidence revealing important role of IDAGL in human diseases. Targeted RT-PCR screen coupled with sequencing of purified PCR products detects widespread transcription at multiple intergenic disease-associated genomic loci (IDAGL) and identifies 96 small non-coding trans-regulatory RNAs of ~ 100-300 nt in length containing SNPs associated with 21 common human disorders (snpRNAs). Functionality of snpRNAs is supported by multiple independent lines of experimental evidence demonstrating their cell-type-specific expression and evolutionary conservation of sequences, genomic coordinates, and biological effects. Analysis of chromatin state signatures, expression profiling experiments using microarray and Q-PCR technologies, and luciferase reporter assays indicate that many IDAGL are Polycomb-regulated long-range enhancers. Expression of snpRNAs in human and mouse cells markedly affects cellular behavior and induces allele-specific clinically-relevant phenotypic changes: NLRP1-locus snpRNAs exert regulatory effects on monocyte/macrophage trans-differentiation, induce prostate cancer (PC) susceptibility snpRNAs, and transform low-malignancy hormone-dependent human PC cells into highly malignant androgen-independent PC. Q-PCR analysis and luciferase reporter assays demonstrate that snpRNA sequences represent allele-specific “decoy” targets of microRNAs which function as SNP-allele-specific modifiers of microRNA expression and activity. We demonstrate that trans-acting RNA molecules facilitating androgen depletion-independent growth (ADIG) in vitro and castration-resistant (CR) phenotype in vivo of PC contain intergenic 8q24-locus SNP variants which were recently linked with increased risk of developing PC. Expression level of 8q24-locus PC susceptibility snpRNAs is regulated by NLRP1-locus snpRNAs, which are transcribed from the intergenic long-range enhancer sequence located in 17p13 region at ~ 30 kb distance from the NLRP1 gene. Q-PCR analysis of clinical PC samples reveals markedly increased snpRNA expression levels in tumor tissues compared to the adjacent normal prostate [122-fold and 45-fold in Gleason 7 tumors (p = 0.03); 370-fold and 127-fold in Gleason 8 tumors (p = 0.0001); for NLRP1-locus and 8q24-locus SnpRNAs, respectively]. Highly concordant expression profiles of the NLRP1-locus snpRNAs and 8q24 CR-locus snpRNAs (r = 0.896; p < 0.0001) in clinical PC samples and experimental evidence of trans-regulatory effects of NLRP1-locus snpRNAs on expression of 8q24-locus SnpRNAs indicate that ADIG and CR phenotype of human PC cells can be triggered by RNA molecules transcribed from the NLRP1-locus intergenic enhancer and down-stream activation of the 8q24-locus snpRNAs. Our results define the intergenic NLRP1 and 8q24 regions as regulatory loci of ADIG and CR phenotype of human PC, reveal previously unknown molecular links between the innate immunity/inflammasome system and development of hormone-independent PC, and identify novel diagnostic and therapeutic targets exploration of which should be highly beneficial for clinical management of PC

Analysis of PDGF-AB and -BB in serum of intact and ovariectomized (OVX) pigs

Abstract only availablePrevious studies in our group demonstrated that terminal microvascular networks in dura mater of ovariectomized (OVX) pigs undergo significant remodeling characterized by a decrease in microvessel density, capillary rarefaction, and increase in blood vessel permeability. It was postulated that post OVX vascular remodeling is estrogen-dependent and could involve changes in expression levels of relevant growth factors and receptors on both systemic and local levels. Comparison of 41 relevant growth factors and receptors in serum of intact female and OVX animals using antibody array revealed most robust changes in the expression levels of platelet-derived growth factors (PDGF) -AB and -BB, both of which are potent regulators of growth and survival in a vascular tissue. To corroborate the data from the antibody array, we conducted SDS-Page and Western blot analysis using monoclonal antibody directed against B chain of PDGF, which recognizes both PDGF-AB and PDGF-BB. The Western blot analysis revealed several species of PDGF-AB and BB possibly existing in porcine serum, notably p24, p36 and p54, which are consistent with differing stages of posttranslational processing and maturation of PDGF. Densitometry analysis confirmed antibody array results showing significant decrease in PDGF-AB and PDGF-BB expression levels in post OVX animals compared to intact female swine. Our ongoing experiments aim at isolating and verifying specific bands, and analysis of the expression levels and autophosphorylation of PDGF receptors alpha and beta in different vascular compartments.Molecular Imaging Progra

Systemic and local changes in PDGF system associated with post ovariectomy microvascular remodeling in pigs [abstract]

Abstract only availablePrevious studies in our group demonstrated that terminal microvascular networks in dura mater of ovariectomized (OVX) pigs undergo significant remodeling characterized by a decrease in microvessel density, capillary rarefaction, and increase in blood vessel permeability. It was postulated that post OVX vascular remodeling is estrogen-dependent and could involve changes in the expression of relevant growth factors and receptors on both systemic and local levels. Systemically, comparison of growth factors and receptors in serum of intact female (IF) and OVX pigs using antibody array revealed most robust changes in expression levels of platelet-derived growth factors (PDGF) -AB and -BB, both of which are potent regulators of growth and survival in vascular tissue. These results were corroborated by Western blot analysis using monoclonal antibody directed against the B chain of PDGF, which recognizes both PDGF-AB and -BB. Densitometry analysis confirmed antibody array results showing a significant decrease in PDGF-AB and -BB expression levels in post OVX animals compared to IF swine. Lower levels of circulating PDGF could translate into a weakened response of systemic repair mechanisms during vascular damage in OVX animals. On a tissue level, however, two months post OVX there was a significant increase in local PDGF expression in OVX animals compared to IF swine accompanied by a corresponding increase in phosphorylation of PDGF receptor alpha. Our current hypothesis is that hypoxic stromal responses, triggered by initial microvessel loss in OVX animals, activate PDGF/VEGF system in an attempt to restore microvasculature via angiogenic processes. Ongoing studies are aimed at identifying other factors and pathways involved in the regulation of post OVX vascular remodeling.Life Sciences Undergraduate Research Opportunity Progra

Fermat Principle in Finsler Spacetimes

It is shown that, on a manifold with a Finsler metric of Lorentzian signature, the lightlike geodesics satisfy the following variational principle. Among all lightlike curves from a point (emission event) to a timelike curve (worldline of receiver), the lightlike geodesics make the arrival time stationary. Here ``arrival time'' refers to a parametrization of the timelike curve. This variational principle can be applied (i) to the vacuum light rays in an alternative spacetime theory, based on Finsler geometry, and (ii) to light rays in an anisotropic non-dispersive medium with a general-relativistic spacetime as background.Comment: 18 pages, submitted to Gen. Rel. Gra

Least action principle for envelope functions in abrupt heterostructures

We apply the envelope function approach to abrupt heterostructures starting with the least action principle for the microscopic wave function. The interface is treated nonperturbatively, and our approach is applicable to mismatched heterostructure. We obtain the interface connection rules for the multiband envelope function and the short-range interface terms which consist of two physically distinct contributions. The first one depends only on the structure of the interface, and the second one is completely determined by the bulk parameters. We discover new structure inversion asymmetry terms and new magnetic energy terms important in spintronic applications.Comment: 4 pages, 1 figur

Corneal Injury Is Associated With Stromal and Vascular Alterations Within Cranial Dura Mater

The cornea and cranial dura mater share sensory innervation. This link raises the possibility that pathological impulses mediated by corneal injury may be transmitted to the cranial dura, trigger dural perivascular/connective tissue nociceptor responses, and induce vascular and stromal alterations affecting dura mater blood and lymphatic vessel functionality. In this study, using a mouse model, we demonstrate for the first time that two weeks after the initial insult, alkaline injury to the cornea leads to remote pathological changes within the coronal suture area of the dura mater. Specifically, we detected significant pro-fibrotic changes in the dural stroma, as well as vascular remodeling characterized by alterations in vascular smooth muscle cell (VSMC) morphology, reduced blood vessel VSMC coverage, endothelial cell expression of the fibroblast specific protein 1, and significant increase in the number of podoplanin-positive lymphatic sprouts. Intriguingly, the deficiency of a major extracellular matrix component, small leucine-rich proteoglycan decorin, modifies both the direction and the extent of these changes. As the dura mater is the most important route for the brain metabolic clearance, these results are of clinical relevance and provide a much-needed link explaining the association between ophthalmic conditions and the development of neurodegenerative diseases