Anatomy Commons^™

Connexin Overexpression Differentially Suppresses Glioma Growth And Contributes To The Bystander Effect Following Hsv-Thymidine Kinase Gene Therapy, T. Jiminez, W. Fox, C. Naus, J. Galipeau, Daniel Belliveau

Daniel J. Belliveau

Neoplastic transformation is frequently associated with a loss of gap junctional intercellular communication and reduced expression of connexins. The introduction of connexin genes into tumor cells reverses the proliferative characteristics of such cells. However, there is very little comparative information on the effects of different connexins on cancer cell growth. We hypothesized that Cx26, Cx32, or Cx43 would display differential growth suppression of C6 glioma cells and uniquely modulate the bystander effect following transduction of C6 cells with HSVtk followed by suicide gene therapy. The bystander phenomenon is the death of a greater number of tumor cells than are expressing …

Pka-Mediated Erk1/2 Inactivation And Hsp70 Gene Expression Following Exercise, C.W. Melling, Matthew Krause, Earl Noble

Jamie Melling

Exercise induces the expression of the cardioprotective protein, Hsp70, through the activation of its transcription factor HSF1. Recently, we reported that administration of a protein kinase A (PKA) inhibitor suppressed exercise-induced hsp70 gene expression, suggesting a role for PKA in the regulation of HSF1 activation in vivo. While the mechanism by which PKA regulates HSF1 is unclear, studies in vitro have reported that HSF1 is phosphorylated on two serine residues by mitogen activated protein kinases (MAPKs); ERK1/2 (ser307) and JNK/SAPK (ser363). As PKA is a regulator of these protein kinases, the current study examined the role of PKA in their …

Enhanced Neurite Outgrowth In Pc12 Cells Mediated By Connexin Hemichannels And Atp, Daniel Belliveau, M. Bani-Yagoub, R. Mcgirr, C. Naus, W. Rushlow

Daniel J. Belliveau

Gap junctions have traditionally been described as transmembrane channels that facilitate intercellular communication via the passage of small molecules. Connexins, the basic building blocks of gap junctions, are expressed in most mammalian tissues including the developing and adult central nervous system. During brain development, connexins are temporally and spatially regulated suggesting they play an important role in the proper formation of the central nervous system. In the current study, connexins 32 and 43 were overexpressed in PC12 cells to determine whether connexins are involved in neuronal differentiation. Both connexin 32 and 43 were appropriately trafficked to the cell membrane following …

Imaging Islets Labeled Wth Magnetic Nanoparticules At 1.5 Tesla, J.H. Tai, Paula Foster, Alma Rosales, Biao Feng, Craig Ha, Violetta Martinez, Soha Ramadan, Jonatan Snir, C.W. Melling, Savita Dhanvantari, Brian Rutt, David White

Jamie Melling

We have developed a magnetic resonance imaging (MRI) technique for imaging Feridex (superparamagnetic iron oxide [SPIO])-labeled islets of Langerhans using a standard clinical 1.5-Tesla (T) scanner and employing steady-state acquisition imaging sequence (3DFIESTA). Both porcine and rat islets were labeled with SPIO by a transfection technique using a combination of poly-l-lysine and electroporation. Electron microscopy demonstrated presence of SPIO particles within the individual islet cells, including beta-cells and particles trapped between cell membranes. Our labeling method produced a transfection rate of 860 pg to 3.4 ng iron per islet, dependent on the size of the islet. The labeling procedure did …

Castration Inhibits The Exercise-Induced Accumulation Of Hsp70 In Male Rodent Cardiac Muscle Tissue, Kevin Milne, David Thorp, C.W. Melling, Earl Noble

Jamie Melling

Intense exercise leads to accumulation of the inducible member of the 70-kDa family of heat shock proteins, Hsp70, in male, but not female, hearts. Estrogen is at least partially responsible for this difference. Because androgen receptors are expressed in the heart and castration leads to decreases in calcium regulatory proteins and altered cardiac function, testosterone (T) or its metabolites could also be involved. We hypothesized that removal of endogenous T production through castration would reduce cardiac Hsp70 accumulation after an acute exercise bout, whereas castrated animals supplemented with 5α-dihydrotestosterone (DHT) would show the intact male response. Fifty-four 8-wk-old male Sprague-Dawley …

Changes In Calcineurin Expression Induced In The Rat Brain By The Administration Of Antipsychotics, W. Rushlow, Y. Seah, Daniel Belliveau, N. Rajakumar

Daniel J. Belliveau

Calcineurin (CN) was recently identified as a susceptibility gene for schizophrenia as well as showing altered RNA expression levels in the post-mortem brains of individuals with schizophrenia. CN knockout mice show a number of behaviours associated with schizophrenia, including deficits in sensorimotor gating, suggesting a link between CN and psychosis. Concurrently, we found, using genome screening techniques, that antipsychotics alter CN expression levels. Therefore, western blotting, in situ hybridization, immunocytochemistry and phosphatase assays were employed to determine what effect antipsychotics have on CN. The results indicate that clozapine, risperidone and haloperidol cause substantial reductions in the A subunit of CN …

Nerve Growth Factor Increases Connexin43 Phosphorylation And Gap Junctional Intercellular Communication, P. Cushing, R. Bhalla, A. Johnson, W. Rushlow, S. Meakin, Daniel Belliveau

Daniel J. Belliveau

The function of gap junctions is regulated by the phosphorylation state of their connexin subunits. Numerous growth factors are known to regulate connexin phosphorylation; however, the effect of nerve growth factor on gap junction function is not understood. The phosphorylation of connexin subunits is a key event during many aspects of the lifecycle of a connexin, including open/close states, assembly/trafficking, and degradation, and thus affects the functionality of the channel. PC12 cells infected with connexin43 (Cx43) retrovirus were used as a neuronal model to characterize the signal transduction pathways activated by nerve growth factor (NGF) that potentially affect the functional …

Lateral Hypothalamic Signaling Mechanisms Underlying Feeding Stimulation: Differential Contributions Of Src Family Tyrosine Kinases To Feeding Triggered Either By Nmda Injection Or By Food Deprivation, Arshad Khan, Herman H. Cheung, Elizabeth R. Gillard, Jennifer A. Palarca, Derek S. Welsbie, James W. Gurd, B. Glenn Stanley

Arshad M. Khan, Ph.D.

No abstract provided.

Ampk Activation Is Not Critical In The Regulation Of Muscle Fa Uptake And Oxidation During Low-Intensity Muscle Contraction, Marcella Raney, Alice Yee, Mark Todd, Lorraine Turcotte

Marcella Raney

To determine the role of AMP-activated protein kinase (AMPK) activation on the regulation of fatty acid (FA) uptake and oxidation, we perfused rat hindquarters with 6 mM glucose, 10 μU/ml insulin, 550 μM palmitate, and [14C]palmitate during rest (R) or electrical stimulation (ES), inducing low-intensity (0.1 Hz) muscle contraction either with or without 2 mM 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR). AICAR treatment significantly increased glucose and FA uptake during R (P < 0.05) but had no effect on either variable during ES (P > 0.05). AICAR treatment significantly increased total FA oxidation (P < 0.05) during both R (0.38 ± 0.11 vs. 0.89 ± 0.1 nmol·min−1·g−1) and ES (0.73 ± 0.11 vs. 2.01 ± 0.1 nmol·min−1·g−1), which was paralleled in both conditions by a significant increase and significant decrease in AMPK and acetyl-CoA carboxylase (ACC) activity, respectively (P < 0.05). Low-intensity muscle contraction increased glucose uptake, FA uptake, and total FA oxidation (P < 0.05) despite no change in AMPK (950.5 ± 35.9 vs. 1,067.7 ± 58.8 nmol·min−1·g−1) or ACC (51.2 ± 6.7 vs. 55.7 ± 2.0 nmol·min−1·g−1) activity from R to ES (P > 0.05). When contraction and AICAR treatment were combined, the AICAR-induced increase in AMPK activity (34%) did not account for the synergistic increase in …

Spine Pathology And Disability At Lesbos, Greece, Anastasia Tsaliki

Dr Anastasia Tsaliki, PhD

No abstract provided.

Regulation Of Myocardial Hsp70 Gene Expression Following Exercise, C.W. Melling, David Thorp, Earl Noble

Jamie Melling

No abstract provided.

Intravenous 2-Deoxy-D-Glucose Injection Rapidly Elevates Levels Of The Phosphorylated Forms Of P44/42 Mitogen-Activated Protein Kinases (Extracellularly Regulated Kinases 1/2) In Rat Hypothalamic Parvicellular Paraventricular Neurons, Arshad Khan, Alan G. Watts

Arshad M. Khan, Ph.D.

No abstract provided.

Ζωϊκά Και Ανθρώπινα Οστά Στα Αρχαιολογικά Σύνολα. Προβληματική Και Διαχωρισμός, Anastasia Tsaliki

Dr Anastasia Tsaliki, PhD

No abstract provided.

"Vampiri" A Trani. Metti Un Masso Sul Morto Iapigio, Giacomo Annibaldis

Dr Anastasia Tsaliki, PhD

No abstract provided.

Retroviral Delivery Of Connexin Genes To Human Breast Tumor Cells Inhibits In Vivo Tumor Growth By A Mechanism That Is Independent Of Significant Gap Junctional Intercellular Communication, H. Qin, Q. Shao, H. Curtis, J. Galipeau, Daniel Belliveau, T. Wang, M. Alaoui-Jamali, D. Laird

Daniel J. Belliveau

The mechanism by which gap junction proteins, connexins, act as potent tumor suppressors remains poorly understood. In this study human breast tumor cells were found to exhibit diverse gap junction phenotypes including (a) undetectable Cx43 and no intercellular communication (HBL100); (b) low levels of Cx43 and sparse intercellular communication (MDA-MB-231); and (c) significant levels of Cx43 and moderate intercellular communication (Hs578T). Although retroviral delivery of Cx43 and Cx26 cDNAs to MDA-MB-231 cells did not achieve an expected substantial rescue of intercellular communication, overexpression of connexin genes did result in a dramatic suppression of tumor growth when connexin-expressing MDA-MB-231 cells were …

Methods For Volume Measurement In 3d Images, Kevin J. Black

Kevin J. Black, MD

Aggregated Dsred-Tagged Cx43 And Over-Expressed Cx43 Are Targeted To Lysosomes In Human Breast Cancer Cells, H. Qin, Q. Shao, Daniel Belliveau, D. Laird

Daniel J. Belliveau

To investigate if either wild-type or aggregated Cx43 is abnormally targeted to lysosomes in human breast tumor cells, we examined the fate of DsRed-tagged Cx43 and over-expressed Cx43 in communication-deficient HBL-100 and MDA-MB-231 cells. DsRed-tagged Cx43 was assembled into gap junctions in control normal rat kidney cells that express endogenous Cx43 but not in Cx43-negative HBL-100 cells. However, when HBL-100 cells were engineered to coexpress wild-type Cx43 a population of DsRed-tagged Cx43 was rescued and assembled into gap junctions. Co-expression of wild-type Cx26 failed to rescue the assembly of DsRed-tagged Cx43 into gap junctions. Immunolocalization studies revealed that DsRed-tagged Cx43 …

Viral Shedding And Biodistribution Of G207, A Multimutated, Conditionally Replicating Herpes Simplex Virus Type 1, After Intracerebral Inoculation In Aotus, T. Todo, F. Feigenbaum, S. Rabkin, F. Lakeman, J. Newsome, P. Johnson, E. Mitchell, Daniel Belliveau, J. Ostrove, R. Martuza

Daniel J. Belliveau

G207 is a multimutated, conditionally replicating herpes simplex virus type 1 (HSV-1) that is currently in clinical trial for patients with malignant glioma. G207 exhibits an efficient oncolytic activity in tumor cells, yet minimal toxicity in normal tissue when injected into the brains of HSV-susceptible mice or nonhuman primates. In this study, we evaluated the shedding and biodistribution of clinical-grade G207 after intracerebral inoculation (3 × 107 pfu) in four New World owl monkeys (Aotus nancymae). Using PCR analyses and viral cultures, neither infectious virus nor viral DNA was detected from tear, saliva, or vaginal secretion samples at any time …

N-Methyl-D-Aspartate Receptor Subunit Nr2b Is Widely Expressed Throughout The Rat Diencephalon: An Immunohistochemical Study, Arshad Khan, B. Glenn Stanley, Lisa Bozzetti, Christina Chin, Cyndi Stivers, Margarita Curras-Collazo

Arshad M. Khan, Ph.D.

No abstract provided.

Lateral Hypothalamic Nmda Receptor Subunits Nr2a And/Or Nr2b Mediate Eating: Immunochemical/Behavioral Evidence, Arshad Khan, Margarita C. Curras, Jennifer Dao, Faizi A. Jamal, Rishi K. Goel, Elizabeth R. Gillard, Stefany D. Wolfsohn, B. Glenn Stanley

Arshad M. Khan, Ph.D.

No abstract provided.

The Second Messenger Camp Elicits Eating By An Anatomically Specific Action In The Perifornical Hypothalamus, Elizabeth R. Gillard, Arshad M. Khan, Rickinder S. Grewal, Bara Mouradi, Stefany D. Wolfsohn, B. Glenn Stanley

Arshad M. Khan, Ph.D.

No abstract provided.

Autocrine Hepatocyte Growth Factor Provides A Local Mechanism For Promoting Axonal Growth, X. Yang, J. Toma, S. Bamji, Daniel Belliveau, J. Kohn, M. Park, F. Miller

Daniel J. Belliveau

In this report, we describe a novel local mechanism necessary for optimal axonal growth that involves hepatocyte growth factor (HGF). Sympathetic neurons of the superior cervical ganglion coexpress bioactive HGF and its receptor, the Met tyrosine kinase, both in vivo and in vitro. Exogenous HGF selectively promotes the growth but not survival of cultured sympathetic neurons; the magnitude of this growth effect is similar to that observed with exogenous NGF. Conversely, HGF antibodies that inhibit endogenous HGF decrease sympathetic neuron growth but have no effect on survival. This autocrine HGF is required locally by sympathetic axons for optimal growth, as …

Colocalization Of Calretinin And Calbindin-D28k With Oxytocin And Vasopressin In Rat Supraoptic Nucleus Neurons: A Quantitative Study, Seiji Miyata, Arshad Khan, Glenn I. Hatton

Arshad M. Khan, Ph.D.

No abstract provided.

Eating Induced By Perifornical Camp Is Behaviorally Selective And Involves Protein Kinase Activity, Elizabeth R. Gillard, Arshad M. Khan, Bara Mouradi, Omkar Nalamwar, B. Glenn Stanley

Arshad M. Khan, Ph.D.

No abstract provided.

Differential Expression Of Gap Junctions In Neurons And Astrocytes Dervied From P19 Embryonal Carcinoma Cells, Daniel Belliveau, J. Bechberger, K. Rodgers, C. Naus

Daniel J. Belliveau

The P19 embryonal carcinoma cell line represents a pluripotential stem cell that can differentiate along the neural or muscle cell lineage when exposed to different environments. Exposure to retinoic acid induces P19 cells to differentiate into neurons and astrocytes that express similar developmental markers as their embryonic counterparts. We examined the expression of gap junction genes during differentiation of these stem cells into neurons and astrocytes. Untreated P19 cells express at least two gap junction proteins, connexins 26 and 43. Connexin32 could not be detected in these cells. Treatment for 96 hr with 0.3 mM retinoic acid induced the P19 …

Blocking Nerve Growth Factor Binding To The P75 Neurotrophin Receptor On Sympathetic Neurons Transiently Reduces Trka Activation But Does Not Affect Neuronal Survival, C. Lachance, Daniel Belliveau, P. Barker

Daniel J. Belliveau

Nerve growth factor interacts with the trkA tyrosine kinase receptor and with the p75 neurotrophin receptor. It is clear that trkA mediates most, if not all, of the stereotypical responses of sympathetic neurons to nerve growth factor but the role of the p75 neurotrophin receptor is unclear. In this study, we have asked whether a functional interaction between p75 neurotrophin receptor and trkA exists in primary sympathetic neurons by disrupting nerve growth factor binding to p75 neurotrophin receptor. Acute assays reveal that blocking antibodies directed against p75 neurotrophin receptor reduce nerve growth factor-mediated trkA tyrosine phosphorylation and reduce the amount …

Transgenic Mice Expressing The Intracellular Domain Of The P75 Neurotrophin Receptor Undergo Neuronal Apoptosis, M. Majdan, C. Lachance, A. Gloster, R. Aloyz, C. Zeindler, S. Bamji, A. Bhakar, Daniel Belliveau, J. Fawcett, F. Miller, P. Barker

Daniel J. Belliveau

We have asked whether p75NTR may play a role in neuronal apoptosis by producing transgenic mice that express the p75NTR intracellular domain within peripheral and central neurons. These animals showed profound reductions in numbers of sympathetic and peripheral sensory neurons as well as cell loss in the neocortex, where there is normally little or no p75NTR expression. Developmental loss of facial motor neurons was not observed, but induced expression of the p75NTR intracellular domain within adult animals led to increased motor neuron death after axotomy. Biochemical analyses suggest that these effects were not attributable to a p75NTR-dependent reduction in trk …

Ngf And Neurotrophin-3 Both Activate Trka On Sympathetic Neurons But Differentially Regulate Survival And Neuritogenesis, Daniel Belliveau, I. Krivko, C. Lachance, J. Kohn, D. Rusakov, D. Kaplan, F. Miller

Daniel J. Belliveau

In this report we examine the biological and molecular basis of the control of sympathetic neuron differentiation and survival by NGF and neurotrophin-3 (NT-3). NT-3 is as efficient as NGF in mediating neuritogenesis and expression of growth-associated genes in NGF-dependent sympathetic neurons, but it is 20-40-fold less efficient in supporting their survival. Both NT-3 and NGF induce similar sustained, long-term activation of TrkA, while NGF is 10-fold more efficient than NT-3 in mediating acute, short-term TrkA activity. At similar acute levels of TrkA activation, NT-3 still mediates neuronal survival two- to threefold less well than NGF. However, a mutant NT-3 …

Adenovirus-Mediated Gene Transfer Of The Tumor Suppressor, P53, Induces Apoptosis In Postmitotic Neurons, R. Slack, Daniel Belliveau, M. Rosenberg, J. Atwal, H. Lochmuller, R. Aloyz, A. Haghighi, B. Lach, P. Seth, E. Cooper, F. Miller

Daniel J. Belliveau

Programmed cell death is an ongoing process in both the developing and the mature nervous system. The tumor suppressor gene, p53, can induce apoptosis in a number of different cell types. Recently, the enhanced expression of p53 has been observed during acute neurological disease. To determine whether p53 overexpression could influence neuronal survival, we used a recombinant adenovirus vector carrying wild type p53 to transduce postmitotic neurons. A control consisting of the same adenovirus vector background but carrying the lacZ reporter expression cassette was used to establish working parameters for the effective genetic manipulation of sympathetic neurons. We have found …

Cellular Localization Of Gap Junction Mrnas In Developing Rat Brain, Daniel Belliveau, C. Naus

Daniel J. Belliveau

We investigated the developmental expression and cellular resolution of connexin32 and 43 mRNA in the rat brain using in situ hybridization. Utilizing 35S-labelled probes, in situ hybridization was performed on sections of embryonic day 20 and postnatal days 3, 10, 15, 30 and adult brain. Connexin32 mRNA was first detected in brainstem nuclei at postnatal day 3 and in the midbrain at postnatal day 15. The level of this message continued to increase to postnatal day 30 where the level of message reached a plateau or slightly decreased by adulthood. The distribution of signal included the medial vestibular nucleus, dorsal …