Life Sciences Commons^™

Expression Of Phosphodiesterase 6 (Pde6) In Human Breast Cancer Cells, Hongli Dong, Kevin P. Claffey, Stefan Brocke, Paul M. Epstein

UCHC Articles - Research

Considerable epidemiological evidence demonstrates a positive association between artificial light at night (LAN) levels and incidence rates of breast cancer, suggesting that exposure to LAN is a risk factor for breast cancer. There is a 30-50% higher risk of breast cancer in the highest LAN exposed countries compared to the lowest LAN countries, and studies showing higher incidence of breast cancer among shift workers exposed to more LAN have led the International Agency for Research on Cancer to classify shift work as a probable human carcinogen. Nevertheless, the means by which light can affect breast cancer is still unknown. In …

One-Day Treatment Of Small Molecule 8-Bromo-Cyclic Amp Analogue Induces Cell-Based Vegf Production For In Vitro Angiogenesis And Osteoblastic Differentiation, Kevin W.-H. Lo, Ho Man Kan, Keith A. Gagnon, Cato T. Laurencin

UCHC Articles - Research

Small molecule based regenerative engineering is emerging as a promising strategy for regenerating bone tissue. Small molecule cAMP analogues have been proposed as novel biofactors for bone repair and regeneration, and while promising, the effect that these small molecules have on angiogenesis, a critical requirement for successful bone regeneration, is still unclear. Our previous research demonstrated that the small molecule cAMP analogue 8-bromoadenosine-3’,5’-cyclic monophosphate (8-Br-cAMP) was able to promote initial osteoblast adhesion on a polymeric scaffold via cAMP signaling cascades. Here, we report that 8-Br-cAMP is capable of inducing in vitro cell-based VEGF production for angiogenesis promotion. We first demonstrated …

Preosteocytes/Osteocytes Have The Potential To Dedifferentiate Becoming A Source Of Osteoblasts, Elena Torreggiani, Brya G. Matthews, Slavica Pejda, Igor Matic, Danka Grcevic, Mark C. Horowitz, Ivo Kalajzic

UCHC Articles - Research

Presently there is no clear evidence for the ability of mature osteogenic lineage cells to dedifferentiate. In order to identify and trace mature osteogenic lineage cells, we have utilized transgenic mouse models in which the dentin matrix protein 1 (Dmp1) promoter drives expression of GFP (active marker) or Cre recombinase (historic label) in preosteocytes/osteocytes. In long bone chip outgrowth cultures, in which cells on the bone surface were enzymatically removed, cells with previous activity of the Dmp1 promoter migrated onto plastic and down-regulated Dmp1-GFP expression. Dmp1Cre-labeled cells from these cultures had the potential to re-differentiate into the osteogenic lineage, while …

Osterix-Cre Labeled Progenitor Cells Contribute To The Formation And Maintenance Of The Bone Marrow Stroma, Yaling Liu, Sara Strecker, Liping Wang, Mark S. Kronenberg, Wen Wang, David W. Rowe, Peter F. Maye

UCHC Articles - Research

We have carried out fate mapping studies using Osterix-EGFPCre and Osterix-CreERt animal models and found Cre reporter expression in many different cell types that make up the bone marrow stroma. Constitutive fate mapping resulted in the labeling of different cellular components located throughout the bone marrow, whereas temporal fate mapping at E14.5 resulted in the labeling of cells within a region of the bone marrow. The identity of cell types marked by constitutive and temporal fate mapping included osteoblasts, adipocytes, vascular smooth muscle, perineural, and stromal cells. Prolonged tracing of embryonic precursors labeled at E14.5dpc revealed the continued …

Utilization Of Transgenic Models In Evaluation Of Osteogenic Differentiation Of Embryonic Stem Cells, Dario Repic, Elena Torreggiani, Tiziana Franceschetti, Brya G. Matthews, Alexander C. Lichtler, Ivo Kalajzic

UCHC Articles - Research

Previous studies reported that embryonic stem cells (ESCs) can be induced to differentiate into cells showing a mature osteoblastic phenotype by culturing them under osteo-inductive conditions. It is probable that osteogenic differentiation requires that ESCs undergo differentiation through an intermediary step involving a mesenchymal lineage precursor. Based on our previous studies indicating that adult mesenchymal progenitor cells express αSMA, we have generated ESCs from transgenic mice in which an αSMA promoter directs the expression of red fluorescent protein (RFP) to mesenchymal progenitor cells. To track the transition of ESC-derived MSCs into mature osteoblasts, we have utilized a bone-specific fragment of …

Ptpn11 Deletion In A Novel Cartilage Cell Causes Metachondromatosis By Activating Hedgehog Signaling, Qian Wu

UCHC Articles - Research

SHP2, encoded by PTPN11, is required for survival, proliferation and differentiation of various cell types^1,2. Germ line activating mutations in PTPN11 cause Noonan Syndrome, while somatic PTPN11 mutations cause childhood myeloproliferative disease and contribute to some solid tumors. Recently, heterozygous inactivating mutations in PTPN11 were found in metachondromatosis, a rare inherited disorder featuring multiple exostoses, endochondromas, joint destruction and bony deformities^3,4. The detailed pathogenesis of this disorder has remained unclear. Here, we used a conditional knockout allele (Ptpn11^fl) and Cre recombinase (Cre) transgenic mice to delete Ptpn11 specifically in …

The Transcriptomics To Proteomics Of Hair Cell Regeneration: Looking For A Hair Cell In A Haystack, Gopinath Rajadinakaran

UCHC Articles - Research

Mature mammals exhibit very limited capacity for regeneration of auditory hair cells, while all non-mammalian vertebrates examined can regenerate them. In an effort to find therapeutic targets for deafness and balance disorders, scientists have examined gene expression patterns in auditory tissues under different developmental and experimental conditions. Microarray technology has allowed the large-scale study of gene expression profiles (transcriptomics) at whole-genome levels, but since mRNA expression does not necessarily correlate with protein expression, other methods, such as microRNA analysis and proteomics, are needed to better understand the process of hair cell regeneration. These technologies and some of the results of …

Subtelomeric Hotspots Of Aberrant 5-Hydroxymethylcytosine-Mediated Epigenetic Modifications During Reprogramming To Pluripotency, Stormy J. Chamberlain, I-Ping Chen

UCHC Articles - Research

Mammalian somatic cells can be directly reprogrammed into induced pluripotent stem cells (iPSCs) by introducing defined sets of transcription factors. Somatic cell reprogramming involves epigenomic reconfiguration, conferring iPSCs with characteristics similar to embryonic stem cells (ESCs). Human ES cells contain 5-hydroxymethylcytosine (5hmC), which is generated through the oxidation of 5-methylcytosine by the TET enzyme family. Here we show that 5hmC levels increase significantly during reprogramming to human iPSCs mainly due to TET1 activation, and this hydroxymethylation change is critical for optimal epigenetic reprogramming, but does not compromise primed pluripotency. Compared with hES cells, we find iPS cells tend to form …

Mmp-3 Mediates Psychosine-Induced Globoid Cell Formation: Implications For Leukodystrophy Pathology, Kumiko Ijichi, Graham D. Brown, Craig S. Moore, Paige N. Winokur, Roberto Pagarigan, Stephen J. Crocker

UCHC Articles - Research

Globoid cell leukodystrophy (GLD) or Krabbe disease, is a fatal demyelinating disease attributed to mutations in the galactocerebrosidase (GALC) gene. Loss of function mutations in GALC result in accumulation of the glycolipid intermediate, galactosylsphingosine (psychosine). Due to the cytotoxicity of psychosine, it has been hypothesized that accumulated psychosine underlie the pathophysiology of GLD. However, the cellular mechanisms of GLD pathophysiology remain unclear. Globoid cells, multinucleated microglia/macrophages in the central nervous system (CNS), are a defining characteristic of GLD. Here we report that exposure of primary glial cultures to psychosine induces the expression and the production of matrix metalloproteinase …

In Vitro Characterization Of Avian Influenza Virus Isolates With A Truncated Ns1 Gene Segment, Aaron Dick

Honors Scholar Theses

Avian Influenza Virus represents a significant threat to the world poultry population, and is a potential threat to humans due to the possibility of cross-species AIV infection. Our approach is to characterize a number of avian virus populations with respect to their content of biologically active particles that include hemagglutinating particles (HAP), plaque forming particles (PFP), interferon inducing particles (IFP), interferon induction-suppressing particles (ISP), defective-interfering particles (DIP), cell-killing particles (CKP) and non-infectious cell killing particles (niCKP) using unique in vitro assays developed for avian influenza virus in the Marcus-Sekellick Laboratory. Specifically, we will use a strain of Avian influenza virus, …

The Sh2 Domain Interaction Landscape, Kazuya Machida, Christopher M. Thompson, Bruce J. Mayer

UCHC Articles - Research

Members of the SH2 domain family modulate signal transduction by binding to short peptides containing phosphorylated tyrosines. Each domain displays a distinct preference for the sequence context of the phosphorylated residue. We have developed a new high-density peptide chip technology that allows probing the affinity of most SH2 domains for a large fraction of the entire complement of tyrosine phosphopeptides in the human proteome. Using this technique we have experimentally identified thousands of putative SH2- peptide interactions for more than 70 different SH2 domains. By integrating this rich data set with orthogonal context-specific information, we have assembled an SH2 mediated …

Computationally Designed Peptide Inhibitors Against The Ubiquitin E3 Ligase Scf Fbx4, Bing Hao

UCHC Articles - Research

Telomerase is a reverse transcriptase that maintains telomere length. Telomerase activity is suppressed in somatic cells such that telomere attrition triggers replicative senescence or apop-tosis. In cancer cells, telomerase is up-regulated or reactivated, effectively making the cell immortal. Previous studies have shown that telomerase activity positively correlates with unfavorable cancer prognosis. Since it was discovered that activation of telomerase is a rate-limiting step in carcinogenesis, telomerase has gained much interest as a drug target. Both screening and structure-based methods have been extensively employed to identify small molecule leads that can selectively disrupt telomerase activity. Strategies commonly used to target telomerase …

Resistive-Pulse Measurements With Nanopipettes: Detection Of Au Nanoparticles And Nanoparticle-Bound Anti-Peanut Igy†, Vigneshwaran Mani, Naimish Sardesai, James F. Rusling

UCHC Articles - Research

Solid-state nanopores have been widely employed in sensing applications from Coulter counters to DNA sequencing devices. The analytical signal in such experiments is the change in ionic current flowing through the orifice caused by the large molecule or nanoparticle translocation through the pore. Conceptually similar nanopipette-based sensors can offer several advantages including the ease of fabrication and small physical size essential for local measurements and experiments in small spaces. This paper describes the first evaluation of nanopipettes with well characterized geometry for resistive-pulse sensing of Au nanoparticles (AuNP), nanoparticles coated with an allergen epitope peptide layer, and AuNP–peptide particles with …

Preconditioning Induces Sustained Neuroprotection By Down Regulation Of Ampk, Louise D. Mccullough, Venugopal Reddy Venna, Jun Li, Sharon E. Benashski, Sami Tarabishy

UCHC Articles - Research

Abstract Background and Purpose—Ischemic preconditioning (IPC) induces endogenous neuroprotection from a subsequent ischemic injury. IPC involves down-regulation of metabolic pathways. As Adenosine 5′-monophosphate-activated protein kinase (AMPK) is a critical sensor of energy balance and plays a major role in cellular metabolism, its role in IPC was investigated.

Methods—A brief 3 minute middle cerebral artery occlusion (MCAO) was employed to induce IPC in male mice 72 hours prior to 90 minute MCAO. Levels of AMPK and pAMPK, the active form of the kinase, were assessed after IPC. A pharmacological activator or inhibitor of AMPK was utilized to determine the …

Computational Analysis Of Rho Gtpase Cycling, Cibele Vieira Falkenberg, Leslie M. Loew

UCHC Articles - Research

The Rho family of GTPases control actin organization during diverse cellular responses (migration, cytokinesis and endocytosis). Although the primary members of this family (RhoA, Rac and Cdc42) have different downstream effects on actin remodeling, the basic mechanism involves targeting to the plasma membrane and activation by GTP binding. Our hypothesis is that the details of GTPase cycling between membrane and cytosol are key to the differential upstream regulation of these biochemical switches. Accordingly, we developed a modeling framework to analyze experimental data for these systems. This analysis can reveal details of GDI-mediated cycling and help distinguish between GDI-dependent and -independent …

Retrospective Study Of Microorganisms Associated With Vascular Access Infections In Hemodialysis Patients, Andre A. Kaplan, Richard S. Feinn, Rajesh V. Lalla

UCHC Articles - Research

Objective

To assess microorganisms associated with vascular access-associated infections (VAIs) in hemodialysis patients, with respect to possible origin from the mouth.

Study Design

A retrospective and comparative analysis of the microbes associated with VAI in hemodialysis patients treated during a 10-year period was performed using the Human Oral Microbiome Database (HOMD).

Results

Of 218 patient records identified, 65 patients collectively experienced 115 VAI episodes. The most common microorganisms involved were Staphylococcus aureus (49.6% of infections), Staphylococcus epidermidis (10.4%), Serratia marcescens (10.4%), Pseudomonas aeruginosa (9.6%), and Enterococcus faecalis / fecum (8.7%). None of these was found in 1% or more of …

Copper Signaling In The Mammalian Nervous System: Synaptic Effects, Eric D. Gaier, Betty A. Eipper, Richard E. Mains

UCHC Articles - Research

Copper (Cu) is an essential metal present at high levels in the CNS. Its role as a co-factor in mitochondrial ATP production and in other essential cuproenzymes is well defined. Menkes and Wilson’s diseases are severe neurodegenerative conditions that demonstrate the importance of Cu transport into the secretory pathway. Brain levels of Cu, which is almost entirely protein bound, exceed extracellular levels by more than a hundred-fold. Cu stored in the secretory pathway is released in a Ca²⁺-dependent manner and can transiently reach concentrations over 100 µM at synapses. The ability of low µM levels of Cu to …