Medicine and Health Sciences Commons^™

Transport Of Ldl-Derived Cholesterol From The Npc1 Compartment To The Er Involves The Trans-Golgi Network And The Snare Protein Complex, Yasuomi Urano, Hiroshi Watanabe, Stephanie R. Murphy, Yohei Shibuya, Yong Geng, Andrew Peden, Catherine Chang, Ta Yuan Chang

Dartmouth Scholarship

Mammalian cells acquire cholesterol mainly from LDL. LDL enter the endosomes, allowing cholesteryl esters to be hydrolyzed by acid lipase. The hydrolyzed cholesterol (LDL-CHOL) enters the Niemann-Pick type C1 (NPC1)-containing endosomal compartment en route to various destinations. Whether the Golgi is involved in LDL-CHOL transport downstream of the NPC1 compartment has not been demonstrated. Using subcellular fractionation and immunoadsorption to enrich for specific membrane fractions, here we show that, when parental Chinese hamster ovary (CHO) cells are briefly exposed to (3)H-cholesteryl linoleate (CL) labeled-LDL, newly liberated (3)H-LDL-CHOL appears in membranes rich in trans-Golgi network (TGN) long before it becomes available …

A Cyclin D1/Microrna 17/20 Regulatory Feedback Loop In Control Of Breast Cancer Cell Proliferation., Zuoren Yu, Chenguang Wang, Min Wang, Zhiping Li, Mathew C Casimiro, Manran Liu, Kongming Wu, James Whittle, Xiaoming Ju, Terry Hyslop, Peter Mccue, Richard G Pestell

Kimmel Cancer Center Faculty Papers

Decreased expression of specific microRNAs (miRNAs) occurs in human tumors, which suggests a function for miRNAs in tumor suppression. Herein, levels of the miR-17-5p/miR-20a miRNA cluster were inversely correlated to cyclin D1 abundance in human breast tumors and cell lines. MiR-17/20 suppressed breast cancer cell proliferation and tumor colony formation by negatively regulating cyclin D1 translation via a conserved 3' untranslated region miRNA-binding site, thereby inhibiting serum-induced S phase entry. The cell cycle effect of miR-17/20 was abrogated by cyclin D1 siRNA and in cyclin D1-deficient breast cancer cells. Mammary epithelial cell-targeted cyclin D1 expression induced miR-17-5p and miR-20a expression …

Demyelinating And Nondemyelinating Strains Of Mouse Hepatitis Virus Differ In Their Neural Cell Tropism., Jayasri Das Sarma, Kathryn Iacono, Lilli Gard, Ryan Marek, Lawrence C. Kenyon, Michael Koval, Susan R. Weiss

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Some strains of mouse hepatitis virus (MHV) can induce chronic inflammatory demyelination in mice that mimics certain pathological features of multiple sclerosis. We have examined neural cell tropism of demyelinating and nondemyelinating strains of MHV in order to determine whether central nervous system (CNS) cell tropism plays a role in demyelination. Previous studies demonstrated that recombinant MHV strains, isogenic other than for the spike gene, differ in the extent of neurovirulence and the ability to induce demyelination. Here we demonstrate that these strains also differ in their abilities to infect a particular cell type(s) in the brain. Furthermore, there is …

A New Model For Hemoglobin Ingestion And Transport By The Human Malaria Parasite Plasmodium Falciparum., Michelle D Lazarus, Timothy G Schneider, Theodore F Taraschi

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

The current model for hemoglobin ingestion and transport by intraerythrocytic Plasmodium falciparum malaria parasites shares similarities with endocytosis. However, the model is largely hypothetical, and the mechanisms responsible for the ingestion and transport of host cell hemoglobin to the lysosome-like food vacuole (FV) of the parasite are poorly understood. Because actin dynamics play key roles in vesicle formation and transport in endocytosis, we used the actin-perturbing agents jasplakinolide and cytochalasin D to investigate the role of parasite actin in hemoglobin ingestion and transport to the FV. In addition, we tested the current hemoglobin trafficking model through extensive analysis of serial …

A Central Function For Perlecan In Skeletal Muscle And Cardiovascular Development, Jason J. Zoeller, Angela Mcquillan, John Whitelock, Shiu-Ying Ho, Renato V. Iozzo

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Perlecan's developmental functions are difficult to dissect in placental animals because perlecan disruption is embryonic lethal. In contrast to mammals, cardiovascular function is not essential for early zebrafish development because the embryos obtain adequate oxygen by diffusion. In this study, we use targeted protein depletion coupled with protein-based rescue experiments to investigate the involvement of perlecan and its C-terminal domain V/endorepellin in zebrafish development. The perlecan morphants show a severe myopathy characterized by abnormal actin filament orientation and disorganized sarcomeres, suggesting an involvement of perlecan in myopathies. In the perlecan morphants, primary intersegmental vessel sprouts, which develop through angiogenesis, fail …

Disruption Of C-Jun Reduces Cellular Migration And Invasion Through Inhibition Of C-Src And Hyperactivation Of Rock Ii Kinase., Xuanmao Jiao, Sanjay Katiyar, Manran Liu, Susette C Mueller, Michael P. Lisanti, Anping Li, Timothy G Pestell, Kongming Wu, Xiaoming Ju, Zhiping Li, Erwin F Wagner, Tatsuo Takeya, Chenguang Wang, Richard G Pestell

Kimmel Cancer Center Faculty Papers

The spread of metastatic tumors to different organs is associated with poor prognosis. The metastatic process requires migration and cellular invasion. The protooncogene c-jun encodes the founding member of the activator protein-1 family and is required for cellular proliferation and DNA synthesis in response to oncogenic signals and plays an essential role in chemical carcinogenesis. The role of c-Jun in cellular invasion remains to be defined. Genetic deletion of c-Jun in transgenic mice is embryonic lethal; therefore, transgenic mice encoding a c-Jun gene flanked by LoxP sites (c-jun(f/f)) were used. c-jun gene deletion reduced c-Src expression, hyperactivated ROCK II signaling, …

Gene Targeting In Adult Rhesus Macaque Fibroblasts, Daniel T. Meehan, Mary Ann Zink, Melissa Mahlen, Marilu Nelson, Warren G. Sanger, Shoukhrat M. Mitalipov, Don P. Wolf, Michel M. Ouellette, Robert B. Norgren

Journal Articles: Genetics, Cell Biology & Anatomy

BACKGROUND: Gene targeting in nonhuman primates has the potential to produce critical animal models for translational studies related to human diseases. Successful gene targeting in fibroblasts followed by somatic cell nuclear transfer (SCNT) has been achieved in several species of large mammals but not yet in primates. Our goal was to establish the protocols necessary to achieve gene targeting in primary culture of adult rhesus macaque fibroblasts as a first step in creating nonhuman primate models of genetic disease using nuclear transfer technology.

RESULTS: A primary culture of adult male fibroblasts was transfected with hTERT to overcome senescence and allow …

Temporal And Functional Profile Of The Transcriptional Regulatory Network In The Early Regenerative Response To Partial Hepatectomy In The Rat., Egle Juskeviciute, Rajanikanth Vadigepalli, Jan B Hoek

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: The goal of these studies was to characterize the transcriptional network regulating changes in gene expression in the remnant liver of the rat after 70% partial hepatectomy (PHx) during the early phase response including the transition of hepatocytes from the quiescent (G0) state and the onset of the G1 phase of the cell cycle. RESULTS: The transcriptome of remnant livers was monitored at 1, 2, 4, and 6 hours after PHx using cDNA microarrays. Differentially regulated genes were grouped into six clusters according their temporal expression profiles. Promoter regions of genes in these clusters were examined for shared transcription …

Transcriptional Regulatory Network Analysis During Epithelial-Mesenchymal Transformation Of Retinal Pigment Epithelium., Craig H Pratt, Rajanikanth Vadigepalli, Praveen Chakravarthula, Gregory E Gonye, Nancy J Philp, Gerald B Grunwald

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

PURPOSE: Phenotypic transformation of retinal pigment epithelial (RPE) cells contributes to the onset and progression of ocular proliferative disorders such as proliferative vitreoretinopathy (PVR). The formation of epiretinal membranes in PVR may involve an epithelial-mesenchymal transformation (EMT) of RPE cells as part of an aberrant wound healing response. While the underlying mechanism remains unclear, this likely involves changes in RPE cell gene expression under the control of specific transcription factors (TFs). Thus, the purpose of the present study was to identify TFs that may play a role in this process.

METHODS: Regulatory regions of genes that are differentially regulated during …

Elucidating A Normal Function Of Huntingtin By Functional And Microarray Analysis Of Huntingtin-Null Mouse Embryonic Fibroblasts., Hua Zhang, Sudipto Das, Quan-Zhen Li, Ioannis Dragatsis, Joyce Repa, Scott Zeitlin, György Hajnóczky, Ilya Bezprozvanny

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: The polyglutamine expansion in huntingtin (Htt) protein is a cause of Huntington's disease (HD). Htt is an essential gene as deletion of the mouse Htt gene homolog (Hdh) is embryonic lethal in mice. Therefore, in addition to elucidating the mechanisms responsible for polyQ-mediated pathology, it is also important to understand the normal function of Htt protein for both basic biology and for HD. RESULTS: To systematically search for a mouse Htt function, we took advantage of the Hdh +/- and Hdh-floxed mice and generated four mouse embryonic fibroblast (MEF) cells lines which contain a single copy of the Hdh …