Skip to content
Home
Robert S. Freeman, Ph.D.

Robert S. Freeman, Ph.D.

Looking for more Information?

Visit my lab website to learn more about my research, collaborators, latest news, etc.

Visit Research Lab Website

About Me

Faculty Appointments

Professor (Part-Time) - Department of Pharmacology and Physiology (SMD)

Credentials

Post-doctoral Training & Residency

Washington University School of Medicine, Department of Molecular Biology and Pharmacology. Mentor: Eugene M. Johnson, Ph.D. 1991 - 1994

Education

PhD | Univ of Cal San Diego. Biochemistry. 1991

BS | University of Delaware. Chemistry. 1985

Awards

Alumni Award for Excellence in Graduate Education. 2008

Paul Stark Professorship in Pharmacology. 1996 - 2000

NRSA Postdoctoral Fellowship. 1992 - 1994

Research

During development of the nervous system, as many as half of all neurons generated are ultimately eliminated by a process known as programmed cell death. Much of this cell death occurs as newly differentiated neurons compete for limiting amounts of survival-promoting 'neurotrophic' factors. Though...
During development of the nervous system, as many as half of all neurons generated are ultimately eliminated by a process known as programmed cell death. Much of this cell death occurs as newly differentiated neurons compete for limiting amounts of survival-promoting 'neurotrophic' factors. Though counterintuitive, the selective death of neurons at specific times during development is critical for sculpting a properly wired nervous system. While programmed cell death is essential for normal development, too much or too little cell death later in life is a confounding factor in diseases ranging from Alzheimer's disease and stroke to brain cancer. Research in the Freeman laboratory is aimed at characterizing the mechanisms that regulate cell death in the mammalian nervous system. More specifically, we aim to identify and understand the critical cell signaling events that, if left unchecked, commit a neuron to die.

Our basic approach involves comparing gene expression and protein function in neurons before and after exposure to a death-inducing stimulus. For example, to study programmed cell death during development, we use a model in which neurons are deprived of the neurotrophic factor nerve growth factor. Using this model, we have discovered new roles during cell death for two proline-modifying enzymes, the prolyl hydroxylase EGLN3 and the peptidyl-prolyl isomerase PIN1. Using techniques and approaches from cell and molecular biology, genetics, and biochemistry, we are (1) determining the effects of knocking out these proteins on cell death during development and disease, (2) identifying their biochemical targets and substrates, and (3) characterizing the pathways that regulate their function in dying neurons.

A second interest of the laboratory concerns the mechanisms by which oxygen availability regulates the survival of developing neurons. Prenatal or perinatal hypoxia and hypoxia-ischemia are important causes of neonatal brain injury and abnormal brain development. To better understand these processes, we are investigating the regulation and function of the hypoxia-inducible factor (HIF) family of transcription factors in neurons exposed to different oxygen tensions. Ultimately, our research efforts are driven by the prospect that the mechanisms we uncover may ultimately contribute to the development of new therapies for cell death-related diseases and disorders of the nervous system.

Publications

Journal Articles

Acidosis induces antimicrobial peptide expression and resistance to uropathogenic infection in kidney collecting duct cells via HIF-1?.

Peng H, Purkerson JM, Freeman RS, Schwaderer AL, Schwartz GJ

American journal of physiology. Renal physiology.. 2020 February 1318 (2):F468-F474. Epub 12/16/2019.

Dual phosphorylation of Ric-8A enhances its ability to mediate G protein ? subunit folding and to stimulate guanine nucleotide exchange.

Papasergi-Scott MM, Stoveken HM, MacConnachie L, Chan PY, Gabay M, Wong D, Freeman RS, Beg AA, Tall GG

Science signaling.. 2018 May 2911 (532)Epub 05/29/2018.

The Mixed-Lineage Kinase Inhibitor URMC-099 Protects Hippocampal Synapses in Experimental Autoimmune Encephalomyelitis.

Bellizzi MJ, Hammond JW, Li H, Gantz Marker, Marker DF, Freeman RS, Gelbard HA

eNeuro.. 2018 5 (6)Epub 12/03/2018.

JNK2 and JNK3 are major regulators of axonal injury-induced retinal ganglion cell death.

Fernandes KA, Harder JM, Fornarola LB, Freeman RS, Clark AF, Pang IH, John SW, Libby RT

Neurobiology of disease.. 2012 May 46 (2):393-401. Epub 02/14/2012.

Protein S blocks the extrinsic apoptotic cascade in tissue plasminogen activator/N-methyl D-aspartate-treated neurons via Tyro3-Akt-FKHRL1 signaling pathway.

Guo H, Barrett TM, Zhong Z, Fernandez JA, Griffin JH, Freeman RS, Zlokovic BV

Molecular neurodegeneration.. 2011 February 36 :13. Epub 02/03/2011.

Protein S protects neurons from excitotoxic injury by activating the TAM receptor Tyro3-phosphatidylinositol 3-kinase-Akt pathway through its sex hormone-binding globulin-like region.

Zhong Z, Wang Y, Guo H, Sagare A, Fernández JA, Bell RD, Barrett TM, Griffin JH, Freeman RS, Zlokovic BV

The Journal of neuroscience : the official journal of the Society for Neuroscience.. 2010 November 1730 (46):15521-34. Epub 1900 01 01.

Oxygen-regulated beta(2)-adrenergic receptor hydroxylation by EGLN3 and ubiquitylation by pVHL.

Xie L, Xiao K, Whalen EJ, Forrester MT, Freeman RS, Fong G, Gygi SP, Lefkowitz RJ, Stamler JS

Science signaling.. 2009 July 72 (78):ra33. Epub 07/07/2009.

Prolyl hydroxylase inhibitors depend on extracellular glucose and hypoxia-inducible factor (HIF)-2alpha to inhibit cell death caused by nerve growth factor (NGF) deprivation: evidence that HIF-2alpha has a role in NGF-promoted survival of sympathetic neurons.

Lomb DJ, Desouza LA, Franklin JL, Freeman RS

Molecular pharmacology.. 2009 May 75 (5):1198-209. Epub 02/09/2009.

The von Hippel-Lindau protein sensitizes renal carcinoma cells to apoptotic stimuli through stabilization of BIM(EL).

Guo Y, Schoell MC, Freeman RS

Oncogene.. 2009 April 2328 (16):1864-74. Epub 03/23/2009.

Small molecule activation of adaptive gene expression: tilorone or its analogs are novel potent activators of hypoxia inducible factor-1 that provide prophylaxis against stroke and spinal cord injury.

Ratan RR, Siddiq A, Aminova L, Langley B, McConoughey S, Karpisheva K, Lee HH, Carmichael T, Kornblum H, Coppola G, Geschwind DH, Hoke A, Smirnova N, Rink C, Roy S, Sen C, Beattie MS, Hart RP, Grumet M, Sun D, Freeman RS, Semenza GL, Gazaryan I

Annals of the New York Academy of Sciences.. 2008 December 1147 :383-94. Epub 1900 01 01.

Pin1 promotes cell death in NGF-dependent neurons through a mechanism requiring c-Jun activity.

Barone MC, Desouza LA, Freeman RS

Journal of neurochemistry.. 2008 July 106 (2):734-45. Epub 04/14/2008.

Prolyl hydroxylase inhibitors delay neuronal cell death caused by trophic factor deprivation.

Lomb DJ, Straub JA, Freeman RS

Journal of neurochemistry.. 2007 December 103 (5):1897-906. Epub 08/30/2007.

EGLN3 prolyl hydroxylase regulates skeletal muscle differentiation and myogenin protein stability.

Fu J, Menzies K, Freeman RS, Taubman MB

The Journal of biological chemistry.. 2007 April 27282 (17):12410-8. Epub 03/06/2007.

A shortcut to mitochondrial signaling and pathology: a commentary on "Nonenzymatic formation of succinate in mitochondria under oxidative stress".

Brookes PS, Freeman RS, Barone MC

Free radical biology & medicine.. 2006 July 141 (1):41-5. Epub 04/01/2006.

Neuronal apoptosis linked to EglN3 prolyl hydroxylase and familial pheochromocytoma genes: developmental culling and cancer.

Lee S, Nakamura E, Yang H, Wei W, Linggi MS, Sajan MP, Farese RV, Freeman RS, Carter BD, Kaelin WG, Schlisio S

Cancer cell.. 2005 August 8 (2):155-67. Epub 1900 01 01.

Expression and secretion of chemotactic cytokines IL-8 and MCP-1 by human endothelial cells after Rickettsia rickettsii infection: regulation by nuclear transcription factor NF-kappaB.

Clifton DR, Rydkina E, Huyck H, Pryhuber G, Freeman RS, Silverman DJ, Sahni SK

International journal of medical microbiology : IJMM.. 2005 August 295 (4):267-78. Epub 1900 01 01.

Inhibition of NGF deprivation-induced death by low oxygen involves suppression of BIMEL and activation of HIF-1.

Xie L, Johnson RS, Freeman RS

The Journal of cell biology.. 2005 March 14168 (6):911-20. Epub 1900 01 01.

Targeting hypoxia-inducible factor (HIF) as a therapeutic strategy for CNS disorders.

Freeman RS, Barone MC

Current drug targets. CNS and neurological disorders. 2005 February 4 (1):85-92. Epub 1900 01 01.

NF-kappaB activation during Rickettsia rickettsii infection of endothelial cells involves the activation of catalytic IkappaB kinases IKKalpha and IKKbeta and phosphorylation-proteolysis of the inhibitor protein IkappaBalpha.

Clifton DR, Rydkina E, Freeman RS, Sahni SK

Infection and immunity.. 2005 January 73 (1):155-65. Epub 1900 01 01.

Apoptosis signaling by the novel compound 3-Cl-AHPC involves increased EGFR proteolysis and accompanying decreased phosphatidylinositol 3-kinase and AKT kinase activities.

Farhana L, Dawson MI, Huang Y, Zhang Y, Rishi AK, Reddy KB, Freeman RS, Fontana JA

Oncogene.. 2004 March 1123 (10):1874-84. Epub 1900 01 01.

NGF deprivation-induced gene expression: after ten years, where do we stand?

Freeman RS, Burch RL, Crowder RJ, Lomb DJ, Schoell MC, Straub JA, Xie L

Progress in brain research.. 2004 146 :111-26. Epub 1900 01 01.

Cytosine arabinoside rapidly activates Bax-dependent apoptosis and a delayed Bax-independent death pathway in sympathetic neurons.

Besirli CG, Deckwerth TL, Crowder RJ, Freeman RS, Johnson EM

Cell death and differentiation.. 2003 September 10 (9):1045-58. Epub 1900 01 01.

SM-20, EGL-9, and the EGLN family of hypoxia-inducible factor prolyl hydroxylases.

Freeman RS, Hasbani DM, Lipscomb EA, Straub JA, Xie L

Molecules and cells.. 2003 August 3116 (1):1-12. Epub 1900 01 01.

Induction of SM-20 in PC12 cells leads to increased cytochrome c levels, accumulation of cytochrome c in the cytosol, and caspase-dependent cell death.

Straub JA, Lipscomb EA, Yoshida ES, Freeman RS

Journal of neurochemistry.. 2003 April 85 (2):318-28. Epub 1900 01 01.

Angiotensin II's antiproliferative effects mediated through AT2-receptors depend on down-regulation of SM-20.

Wolf G, Harendza S, Schroeder R, Wenzel U, Zahner G, Butzmann U, Freeman RS, Stahl RA

Laboratory investigation; a journal of technical methods and pathology.. 2002 October 82 (10):1305-17. Epub 1900 01 01.

Analysis of the NF-kappa B and PI 3-kinase/Akt survival pathways in nerve growth factor-dependent neurons.

Sarmiere PD, Freeman RS

Molecular and cellular neurosciences.. 2001 September 18 (3):320-31. Epub 1900 01 01.

SM-20 is a novel mitochondrial protein that causes caspase-dependent cell death in nerve growth factor-dependent neurons.

Lipscomb EA, Sarmiere PD, Freeman RS

The Journal of biological chemistry.. 2001 February 16276 (7):5085-92. Epub 11/01/2000.

Glycogen synthase kinase-3 beta activity is critical for neuronal death caused by inhibiting phosphatidylinositol 3-kinase or Akt but not for death caused by nerve growth factor withdrawal.

Crowder RJ, Freeman RS

The Journal of biological chemistry.. 2000 November 3275 (44):34266-71. Epub 1900 01 01.

The survival of sympathetic neurons promoted by potassium depolarization, but not by cyclic AMP, requires phosphatidylinositol 3-kinase and Akt.

Crowder RJ, Freeman RS

Journal of neurochemistry.. 1999 August 73 (2):466-75. Epub 1900 01 01.

Expression of the SM-20 gene promotes death in nerve growth factor-dependent sympathetic neurons.

Lipscomb EA, Sarmiere PD, Crowder RJ, Freeman RS

Journal of neurochemistry.. 1999 July 73 (1):429-32. Epub 1900 01 01.

Nerve growth factor-dependent activation of NF-kappaB contributes to survival of sympathetic neurons.

Maggirwar SB, Sarmiere PD, Dewhurst S, Freeman RS

The Journal of neuroscience : the official journal of the Society for Neuroscience.. 1998 December 1518 (24):10356-65. Epub 1900 01 01.

Phosphatidylinositol 3-kinase and Akt protein kinase are necessary and sufficient for the survival of nerve growth factor-dependent sympathetic neurons.

Crowder RJ, Freeman RS

The Journal of neuroscience : the official journal of the Society for Neuroscience.. 1998 April 1518 (8):2933-43. Epub 1900 01 01.

Altered gene expression in neurons during programmed cell death: identification of c-jun as necessary for neuronal apoptosis.

Estus S, Zaks WJ, Freeman RS, Gruda M, Bravo R, Johnson EM

The Journal of cell biology.. 1994 December 127 (6 Pt 1):1717-27. Epub 1900 01 01.

Analysis of cell cycle-related gene expression in postmitotic neurons: selective induction of Cyclin D1 during programmed cell death.

Freeman RS, Estus S, Johnson EM

Neuron.. 1994 February 12 (2):343-55. Epub 1900 01 01.

NGF deprivation and neuronal degeneration trigger altered beta-amyloid precursor protein gene expression in the rat superior cervical ganglia in vivo and in vitro.

Smith CJ, Johnson EM, Osborne P, Freeman RS, Neveu I, Brachet P

Brain research. Molecular brain research.. 1993 March 17 (3-4):328-34. Epub 1900 01 01.

Cell death genes in invertebrates and (maybe) vertebrates.

Freeman RS, Estus S, Horigome K, Johnson EM

Current opinion in neurobiology.. 1993 February 3 (1):25-31. Epub 1900 01 01.

Phosphorylation of conserved serine residues does not regulate the ability of mosxe protein kinase to induce oocyte maturation or function as cytostatic factor.

Freeman RS, Meyer AN, Li J, Donoghue DJ

The Journal of cell biology.. 1992 February 116 (3):725-35. Epub 1900 01 01.

Protein kinases and protooncogenes: biochemical regulators of the eukaryotic cell cycle.

Freeman RS, Donoghue DJ

Biochemistry.. 1991 March 530 (9):2293-302. Epub 1900 01 01.

Meiotic induction by Xenopus cyclin B is accelerated by coexpression with mosXe.

Freeman RS, Ballantyne SM, Donoghue DJ

Molecular and cellular biology.. 1991 March 11 (3):1713-7. Epub 1900 01 01.

Effects of the v-mos oncogene on Xenopus development: meiotic induction in oocytes and mitotic arrest in cleaving embryos.

Freeman RS, Kanki JP, Ballantyne SM, Pickham KM, Donoghue DJ

The Journal of cell biology.. 1990 August 111 (2):533-41. Epub 1900 01 01.

Transforming mutant v-mos protein kinases that are deficient in in vitro autophosphorylation.

Freeman RS, Donoghue DJ

Molecular and cellular biology.. 1989 September 9 (9):4087-90. Epub 1900 01 01.

Xenopus homolog of the mos protooncogene transforms mammalian fibroblasts and induces maturation of Xenopus oocytes.

Freeman RS, Pickham KM, Kanki JP, Lee BA, Pena SV, Donoghue DJ

Proceedings of the National Academy of Sciences of the United States of America.. 1989 August 86 (15):5805-9. Epub 1900 01 01.

Books

Cell Death in Diseases of the Nervous System (1998)

Chapter: The cell cycle and neuronal cell death

Neuronal Cell Death and Repair (1993)

Chapter: Molecular mechanism of programmed cell death in the developing nervous system