Publications by authors named "Virginia M Goettl"

18 Publications

  • Page 1 of 1

Preclinical efficacy for a novel tyrosine kinase inhibitor, ArQule 531 against acute myeloid leukemia.

J Hematol Oncol 2020 01 28;13(1). Epub 2020 Jan 28.

Division of Hematology, Department of Internal Medicine, Comprehensive Cancer Center, The Ohio State University, Columbus, 455 Wiseman Hall, 400 West 12th Avenue, Columbus, OH, 43210, USA.

Background: Acute myeloid leukemia (AML) is the most common type of adult leukemia. Several studies have demonstrated that oncogenesis in AML is enhanced by kinase signaling pathways such as Src family kinases (SFK) including Src and Lyn, spleen tyrosine kinase (SYK), and bruton's tyrosine kinase (BTK). Recently, the multi-kinase inhibitor ArQule 531 (ARQ 531) has demonstrated potent inhibition of SFK and BTK that translated to improved pre-clinical in vivo activity as compared with the irreversible BTK inhibitor ibrutinib in chronic lymphocytic leukemia (CLL) models. Given the superior activity of ARQ 531 in CLL, and recognition that this molecule has a broad kinase inhibition profile, we pursued its application in pre-clinical models of AML.

Methods: The potency of ARQ 531 was examined in vitro using FLT3 wild type and mutated (ITD) AML cell lines and primary samples. The modulation of pro-survival kinases following ARQ 531 treatment was determined using AML cell lines. The effect of SYK expression on ARQ 531 potency was evaluated using a SYK overexpressing cell line (Ba/F3 murine cells) constitutively expressing FLT3-ITD. Finally, the in vivo activity of ARQ 531 was evaluated using MOLM-13 disseminated xenograft model.

Results: Our data demonstrate that ARQ 531 treatment has anti-proliferative activity in vitro and impairs colony formation in AML cell lines and primary AML cells independent of the presence of a FLT3 ITD mutation. We demonstrate decreased phosphorylation of oncogenic kinases targeted by ARQ 531, including SFK (Tyr416), BTK, and fms-related tyrosine kinase 3 (FLT3), ultimately leading to changes in down-stream targets including SYK, STAT5a, and ERK1/2. Based upon in vitro drug synergy data, we examined ARQ 531 in the MOLM-13 AML xenograft model alone and in combination with venetoclax. Despite ARQ 531 having a less favorable pharmacokinetics profile in rodents, we demonstrate modest single agent in vivo activity and synergy with venetoclax.

Conclusions: Our data support consideration of the application of ARQ 531 in combination trials for AML targeting higher drug concentrations in vivo.
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http://dx.doi.org/10.1186/s13045-019-0821-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6988309PMC
January 2020

Eμ-TCL1xMyc: A Novel Mouse Model for Concurrent CLL and B-Cell Lymphoma.

Clin Cancer Res 2019 10 11;25(20):6260-6273. Epub 2019 Jul 11.

Division of Hematology, The Ohio State University, Columbus, Ohio.

Purpose: Aberrant Myc expression is a major factor in the pathogenesis of aggressive lymphoma, and these lymphomas, while clinically heterogeneous, often are resistant to currently available treatments and have poor survival. Myc expression can also be seen in aggressive lymphomas that are observed in the context of CLL, and we sought to develop a mouse model that could be used to study therapeutic strategies for aggressive lymphoma in the context of CLL.

Experimental Design: We crossed the Eμ-TCL1 mouse model with the Eμ-Myc mouse model to investigate the clinical phenotype associated with B-cell-restricted expression of these oncogenes. The resulting malignancy was then extensively characterized, from both a clinical and biologic perspective.

Results: Eμ-TCL1xMyc mice uniformly developed highly aggressive lymphoid disease with histologically, immunophenotypically, and molecularly distinct concurrent CLL and B-cell lymphoma, leading to a significantly reduced lifespan. Injection of cells from diseased Eμ-TCL1xMyc into WT mice established a disease similar to that in the double-transgenic mice. Both Eμ-TCL1xMyc mice and mice with disease after adoptive transfer failed to respond to ibrutinib. Effective and durable disease control was, however, observed by selective inhibition of nuclear export protein exportin-1 (XPO1) using a compound currently in clinical development for relapsed/refractory malignancies, including CLL and lymphoma.

Conclusions: The Eμ-TCL1xMyc mouse is a new preclinical tool for testing experimental drugs for aggressive B-cell lymphoma, including in the context of CLL.
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http://dx.doi.org/10.1158/1078-0432.CCR-19-0273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6801062PMC
October 2019

Selective targeting of NAMPT by KPT-9274 in acute myeloid leukemia.

Blood Adv 2019 02;3(3):242-255

Division of Hematology.

Treatment options for acute myeloid leukemia (AML) remain extremely limited and associated with significant toxicity. Nicotinamide phosphoribosyltransferase (NAMPT) is involved in the generation of NAD and a potential therapeutic target in AML. We evaluated the effect of KPT-9274, a p21-activated kinase 4/NAMPT inhibitor that possesses a unique NAMPT-binding profile based on in silico modeling compared with earlier compounds pursued against this target. KPT-9274 elicited loss of mitochondrial respiration and glycolysis and induced apoptosis in AML subtypes independent of mutations and genomic abnormalities. These actions occurred mainly through the depletion of NAD, whereas genetic knockdown of p21-activated kinase 4 did not induce cytotoxicity in AML cell lines or influence the cytotoxic effect of KPT-9274. KPT-9274 exposure reduced colony formation, increased blast differentiation, and diminished the frequency of leukemia-initiating cells from primary AML samples; KPT-9274 was minimally cytotoxic toward normal hematopoietic or immune cells. In addition, KPT-9274 improved overall survival in vivo in 2 different mouse models of AML and reduced tumor development in a patient-derived xenograft model of AML. Overall, KPT-9274 exhibited broad preclinical activity across a variety of AML subtypes and warrants further investigation as a potential therapeutic agent for AML.
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http://dx.doi.org/10.1182/bloodadvances.2018024182DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6373756PMC
February 2019

The BTK Inhibitor ARQ 531 Targets Ibrutinib-Resistant CLL and Richter Transformation.

Cancer Discov 2018 10 9;8(10):1300-1315. Epub 2018 Aug 9.

Department of Internal Medicine, Division of Hematology, Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.

Targeted inhibition of Bruton tyrosine kinase (BTK) with the irreversible inhibitor ibrutinib has improved outcomes for patients with hematologic malignancies, including chronic lymphocytic leukemia (CLL). Here, we describe preclinical investigations of ARQ 531, a potent, reversible inhibitor of BTK with additional activity against Src family kinases and kinases related to ERK signaling. We hypothesized that targeting additional kinases would improve global inhibition of signaling pathways, producing more robust responses. treatment of patient CLL cells with ARQ 531 decreases BTK-mediated functions including B-cell receptor (BCR) signaling, viability, migration, CD40 and CD86 expression, and NF-κB gene transcription. , ARQ 531 was found to increase survival over ibrutinib in a murine Eμ-TCL1 engraftment model of CLL and a murine Eμ-MYC/TCL1 engraftment model resembling Richter transformation. Additionally, ARQ 531 inhibits CLL cell survival and suppresses BCR-mediated activation of C481S BTK and PLCγ2 mutants, which facilitate clinical resistance to ibrutinib. This study characterizes a rationally designed kinase inhibitor with efficacy in models recapitulating the most common mechanisms of acquired resistance to ibrutinib. Reversible BTK inhibition is a promising strategy to combat progressive CLL, and multikinase inhibition demonstrates superior efficacy to targeted ibrutinib therapy in the setting of Richter transformation. .
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http://dx.doi.org/10.1158/2159-8290.CD-17-1409DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6261467PMC
October 2018

BRD4 Profiling Identifies Critical Chronic Lymphocytic Leukemia Oncogenic Circuits and Reveals Sensitivity to PLX51107, a Novel Structurally Distinct BET Inhibitor.

Cancer Discov 2018 04 31;8(4):458-477. Epub 2018 Jan 31.

Division of Hematology, Department of Medicine, The Ohio State University, Columbus, Ohio.

Bromodomain and extra-terminal (BET) family proteins are key regulators of gene expression in cancer. Herein, we utilize BRD4 profiling to identify critical pathways involved in pathogenesis of chronic lymphocytic leukemia (CLL). BRD4 is overexpressed in CLL and is enriched proximal to genes upregulated or expressed in CLL with known functions in disease pathogenesis and progression. These genes, including key members of the B-cell receptor (BCR) signaling pathway, provide a rationale for this therapeutic approach to identify new targets in alternative types of cancer. Additionally, we describe PLX51107, a structurally distinct BET inhibitor with novel and pharmacologic properties that emulates or exceeds the efficacy of BCR signaling agents in preclinical models of CLL. Herein, the discovery of the involvement of BRD4 in the core CLL transcriptional program provides a compelling rationale for clinical investigation of PLX51107 as epigenetic therapy in CLL and application of BRD4 profiling in other cancers. To date, functional studies of BRD4 in CLL are lacking. Through integrated genomic, functional, and pharmacologic analyses, we uncover the existence of BRD4-regulated core CLL transcriptional programs and present preclinical proof-of-concept studies validating BET inhibition as an epigenetic approach to target BCR signaling in CLL. .
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http://dx.doi.org/10.1158/2159-8290.CD-17-0902DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5882533PMC
April 2018

Bruton's tyrosine kinase (BTK) function is important to the development and expansion of chronic lymphocytic leukemia (CLL).

Blood 2014 Feb 5;123(8):1207-13. Epub 2013 Dec 5.

Division of Hematology, Department of Internal Medicine and Comprehensive Cancer Center, The Ohio State University, Columbus, OH;

Chronic lymphocytic leukemia (CLL) is characterized by constitutive activation of the B-cell receptor (BCR) signaling pathway, but variable responsiveness of the BCR to antigen ligation. Bruton's tyrosine kinase (BTK) shows constitutive activity in CLL and is the target of irreversible inhibition by ibrutinib, an orally bioavailable kinase inhibitor that has shown outstanding activity in CLL. Early clinical results in CLL with other reversible and irreversible BTK inhibitors have been less promising, however, raising the question of whether BTK kinase activity is an important target of ibrutinib and also in CLL. To determine the role of BTK in CLL, we used patient samples and the Eμ-TCL1 (TCL1) transgenic mouse model of CLL, which results in spontaneous leukemia development. Inhibition of BTK in primary human CLL cells by small interfering RNA promotes apoptosis. Inhibition of BTK kinase activity through either targeted genetic inactivation or ibrutinib in the TCL1 mouse significantly delays the development of CLL, demonstrating that BTK is a critical kinase for CLL development and expansion and thus an important target of ibrutinib. Collectively, our data confirm the importance of kinase-functional BTK in CLL.
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http://dx.doi.org/10.1182/blood-2013-07-515361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3931190PMC
February 2014

Oral administration of a small molecule targeted to block proNGF binding to p75 promotes myelin sparing and functional recovery after spinal cord injury.

J Neurosci 2013 Jan;33(2):397-410

Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.

The lack of effective therapies for spinal cord injury points to the need for identifying novel targets for therapeutic intervention. Here we report that a small molecule, LM11A-31, developed to block proNGF-p75 interaction and p75-mediated cell death crosses the blood-brain barrier efficiently when delivered orally. Administered starting 4 h postinjury, LM11A-31 promotes functional recovery without causing any toxicity or increased pain in a mouse model of spinal contusion injury. In both weight-bearing open-field tests and nonweight-bearing swim tests, LM11A-31 was effective in improving motor function and coordination. Such functional improvement correlated with a >50% increase in the number of surviving oligodendrocytes and myelinated axons. We also demonstrate that LM11A-31 indeed inhibits proNGF-p75 interaction in vivo, thereby curtailing the JNK3-mediated apoptotic cascade. These results thus highlight p75 as a novel therapeutic target for an orally delivered treatment for spinal cord injury.
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http://dx.doi.org/10.1523/JNEUROSCI.0399-12.2013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3710149PMC
January 2013

17-DMAG targets the nuclear factor-kappaB family of proteins to induce apoptosis in chronic lymphocytic leukemia: clinical implications of HSP90 inhibition.

Blood 2010 Jul 29;116(1):45-53. Epub 2010 Mar 29.

Department of Internal Medicine, Division of Hematology and Oncology, Comprehensive Cancer Center at the Ohio State University, 410West 12th Avenue, Columbus, OH 43210, USA.

The HSP90 client chaperone interaction stabilizes several important enzymes and antiapoptotic proteins, and pharmacologic inhibition of HSP90 results in rapid client protein degradation. Therefore, HSP90 inhibition is an attractive therapeutic approach when this protein is active, a phenotype commonly observed in transformed but not normal cells. However, preclinical studies with HSP90 inhibitors such as 17-AAG demonstrated depletion of only a subset of client proteins and very modest tumor cytotoxicity in chronic lymphocytic leukemia (CLL) cells. Herein, we describe another HSP90 inhibitor, 17-DMAG, which is cytotoxic to CLL but not normal lymphocytes. Treatment with 17-DMAG leads to depletion of the HSP90 client protein IKK, resulting in diminished NF-kappaB p50/p65 DNA binding, decreased NF-kappaB target gene transcription, and caspase-dependent apoptosis. Furthermore, treatment with 17-DMAG significantly decreased the white blood cell count and prolonged the survival in a TCL1-SCID transplant mouse model. The ability of 17-DMAG to function as an NF-kappaB inhibitor is of great interest clinically, as few currently available CLL drugs target this transcription factor. Therefore, the effect of 17-DMAG on NF-kappaB signaling pathways represents a novel therapy warranting further clinical pursuit in this and other B-cell lymphoproliferative disorders.
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http://dx.doi.org/10.1182/blood-2010-01-263756DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2904580PMC
July 2010

The novel plant-derived agent silvestrol has B-cell selective activity in chronic lymphocytic leukemia and acute lymphoblastic leukemia in vitro and in vivo.

Blood 2009 May 3;113(19):4656-66. Epub 2009 Feb 3.

Department of Internal Medicine, The Ohio State University, Columbus, OH, USA.

Therapeutic options for advanced B-cell acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia (CLL) are limited. Available treatments can also deplete T lymphocytes, leaving patients at risk of life-threatening infections. In the National Cancer Institute cell line screen, the structurally unique natural product silvestrol produces an unusual pattern of cytotoxicity that suggests activity in leukemia and selectivity for B cells. We investigated silvestrol efficacy using primary human B-leukemia cells, established B-leukemia cell lines, and animal models. In CLL cells, silvestrol LC(50) (concentration lethal to 50%) is 6.9 nM at 72 hours. At this concentration, there is no difference in sensitivity of cells from patients with or without the del(17p13.1) abnormality. In isolated cells and whole blood, silvestrol is more cytotoxic toward B cells than T cells. Silvestrol causes early reduction in Mcl-1 expression due to translational inhibition with subsequent mitochondrial damage, as evidenced by reactive oxygen species generation and membrane depolarization. In vivo, silvestrol causes significant B-cell reduction in Emu-Tcl-1 transgenic mice and significantly extends survival of 697 xenograft severe combined immunodeficient (SCID) mice without discernible toxicity. These data indicate silvestrol has efficacy against B cells in vitro and in vivo and identify translational inhibition as a potential therapeutic target in B-cell leukemias.
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http://dx.doi.org/10.1182/blood-2008-09-175430DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2680369PMC
May 2009

Reciprocal regulation of nuclear factor kappa B and its inhibitor ZAS3 after peripheral nerve injury.

BMC Neurosci 2006 Jan 12;7. Epub 2006 Jan 12.

Department of Molecular and Cellular Biochemistry, Ohio State University, OH 43210, USA.

Background: NF-kappaB binds to the kappaB motif to regulate transcription of genes involved in growth, immunity and inflammation, and plays a pivotal role in the production of pro-inflammatory cytokines after nerve injuries. The zinc finger protein ZAS3 also binds to the kappaB or similar motif. In addition to competition for common DNA sites, in vitro experiments have shown that ZAS3 can inhibit NF-kappaB via the association with TRAF2 to inhibit the nuclear translocation of NF-kappaB. However, the physiological significance of the ZAS3-mediated inhibition of NF-kappaB has not been demonstrated. The purpose of this study is to characterize ZAS3 proteins in nervous tissues and to use spinal nerve ligation, a neuropathic pain model, to demonstrate a functional relationship between ZAS3 and NF-kappaB.

Results: Immunohistochemical experiments show that ZAS3 is expressed in specific regions of the central and peripheral nervous system. Abundant ZAS3 expression is found in the trigeminal ganglion, hippocampal formation, dorsal root ganglia, and motoneurons. Low levels of ZAS3 expressions are also found in the cerebral cortex and in the grey matter of the spinal cord. In those nervous tissues, ZAS3 is expressed mainly in the cell bodies of neurons and astrocytes. Together with results of Western blot analyses, the data suggest that ZAS3 protein isoforms with differential cellular distribution are produced in a cell-specific manner. Further, neuropathic pain confirmed by persistent mechanical allodynia was manifested in rats seven days after L5 and L6 lumbar spinal nerve ligation. Changes in gene expression, including a decrease in ZAS3 and an increase in the p65 subunit of NF-kappaB were observed in dorsal root ganglion ipsilateral to the ligation when compared to the contralateral side.

Conclusion: ZAS3 is expressed in nervous tissues involved in cognitive function and pain modulation. The down-regulation of ZAS3 after peripheral nerve injury may lead to activation of NF-kappaB, allowing Wallerian regeneration and induction of NF-kappaB-dependent gene expression, including pro-inflammatory cytokines. We propose that reciprocal changes in the expression of ZAS3 and NF-kappaB might generate neuropathic pain after peripheral nerve injury.
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http://dx.doi.org/10.1186/1471-2202-7-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1361774PMC
January 2006

Anti-fibroblast growth factor-2 antibodies attenuate mechanical allodynia in a rat model of neuropathic pain.

J Mol Neurosci 2005 ;27(3):315-24

Department of Internal Medicine, The Ohio State University, Columbus, OH, USA.

Peripheral nerve injury leads to the activation of spinal cord astrocytes, which contribute to maintaining neuropathic (NP) pain behavior. Fibroblast growth factor-2 (FGF-2), a neurotrophic and gliogenic factor, is upregulated by spinal cord astrocytes in response to ligation of spinal nerves L5 and L6 (spinal nerve ligation [SpNL]). To evaluate the contribution of spinal astroglial FGF-2 to mechanical allodynia following SpNL, neutralizing antibodies to FGF-2 were injected intrathecally. Administration of 18 microg of anti-FGF-2 antibodies attenuated mechanical allodynia at day 21 after SpNL and reduced FGF-2 and glial acidic fibrillary protein mRNA expression and immunoreactivity in the L5 spinal cord segment of rats with SpNL. These results suggest that endogenous astroglial FGF-2 contributes to maintaining NP tactile allodynia associated with reactivity of spinal cord astrocytes and that inhibition of spinal FGF-2 ameliorates NP pain signs.
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http://dx.doi.org/10.1385/JMN:27:3:315DOI Listing
February 2006

Glutamate uptake is attenuated in spinal deep dorsal and ventral horn in the rat spinal nerve ligation model.

Brain Res 2005 Apr;1041(1):38-47

Department of Physiology and Cell Biology, 304 Hamilton Hall, 1645 Neil Avenue, The Ohio State University, Columbus, OH 43210, USA.

Alteration of glutamatergic (GLU) neurotransmission within the spinal cord contributes to hyperalgesic and allodynic responses following nerve injury. In particular, changes in expression and efficacy of glutamate transporters have been reported. Excitatory, pain transmitting primary afferent neurons utilizing glutamate as an excitatory neurotransmitter project to both superficial (I-II) and deep (III-V) laminae of the dorsal horn. These experiments were designed to examine changes in glutamate uptake occurring concomitantly within the spinal deep dorsal and ventral horn in situ after experimentally induced neuropathic pain. In vivo voltammetry, using microelectrode arrays configured for enzyme-based detection of GLU were employed. Sprague-Dawley rats had either sham surgery or tight ligation of L5 and L6 spinal nerves (SNL). Four to six weeks later, the L4-L6 spinal cord of chloral hydrate-anesthetized animals was exposed, and ceramic-based glutamate microelectrodes equipped with glass micropipettes 50 microm from the recording surfaces were placed stereotaxically at sites within the spinal cord. Pressure ejection of GLU into the ipsilateral L5-L6 spinal cord resulted in a 72% reduction of GLU uptake in SNL rats compared to sham controls in the ipsilateral L5-L6 deep dorsal horn and a 96% reduction in the ventral horn. In contrast, in the same animals, the contralateral L5-L6 or the ipsilateral L4 spinal cord showed no change in glutamate uptake. The data suggest that spinal nerve ligation produced attenuated glutamate uptake activity extending into the deep dorsal and ventral horn. The study suggests that plasticity related to spinal nerve injury produces widespread alteration in glutamate transporter function that may contribute to the pathophysiology of neuropathic pain.
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http://dx.doi.org/10.1016/j.brainres.2005.01.088DOI Listing
April 2005

Proteomic identification of brainstem cytosolic proteins in a neuropathic pain model.

Brain Res Mol Brain Res 2004 Sep;128(2):193-200

Neuroproteomic Center, Department of Neurobiology, Duke University Medical Center, Durham, NC, USA.

Neuropathic pain involves co-regulation of many genes and their translational products in both peripheral and central nervous system. We used proteomics approaches to investigate expressional changes in cytosolic protein levels in rat brainstem tissues following ligation of lumbar 5 and 6 (L5, L6) spinal nerves, which generates a model of peripheral neuropathic pain (NP). Proteins from brainstem tissue homogenates of NP and SHAM animals were fractionated by two-dimensional (2-DE) gel electrophoresis to produce a high-resolution map of the brainstem soluble proteins. Proteins showing altered expression levels between NP and SHAM were selected. Isolated proteins were in-gel trypsin-digested and the resulting peptides were analyzed by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. Using the mass spectrometric data, we were able to identify 17 proteins of interest through searches of the Swiss-Prot and NCBi nonredundant protein sequence database. Several of the identified proteins, including fatty acid binding protein-brain (FABP-B), major histocompatibility complex (MHC) class 1, T-cell receptor (TCR) alpha chain, and interleukin-1 (IL-1), showed significantly higher levels in the NP rat brainstem. Proteomic analysis has identified several proteins with differential expression levels in NP as compared to SHAM. However, the function of the proteins identified is postulated; therefore, further experiments are required to determine the true role of each protein in NP.
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http://dx.doi.org/10.1016/j.molbrainres.2004.06.037DOI Listing
September 2004

Differential change in mRNA expression of p75 and Trk neurotrophin receptors in nucleus gracilis after spinal nerve ligation in the rat.

Exp Neurol 2004 Jun;187(2):533-6

Division of Rheumatology, Immunology and Allergy, Department of Internal Medicine, S-2056 William H. Davis Medical Research Center, The Ohio State University College of Medicine and Public Health, Columbus, OH 43210, USA.

In peripheral neuropathy (PN), dorsal column (DC) fibers that synapse in the nucleus gracilis (NuGr) mediate expression of mechanical allodynia and have increased expression of brain-derived neurotrophic factor (BDNF). Neurotrophins (NTs) are implicated in pathology or repair in PN. To assess NTs in the NuGr in PN, mRNA expression of BDNF, nerve growth factor (NGF), and NT receptors TrkA, TrkB, and p75 was determined 1 week after ligation of L5 and L6 spinal nerves (SNL). Laser capture microdissection was used to collect NuGr tissue followed by reverse-transcription (RT)-PCR. TrkA, TrkB, and NGF mRNA levels decreased, whereas p75 mRNA increased, in ipsilateral SNL NuGr compared with SHAM; BDNF was undetectable. Decreased Trk mRNA may result in decreased NT activity in the NuGr. The p75 receptor influences Trk activity and cell survival, thus its role in PN warrants further investigation.
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http://dx.doi.org/10.1016/j.expneurol.2004.03.011DOI Listing
June 2004

Sciatic nerve axotomy in aged rats: response of motoneurons and the effect of GM1 ganglioside treatment.

Brain Res 2003 Apr;968(1):44-53

Department of Pharmacology, The Ohio State University College of Medicine and Public Health, 43210, Columbus, OH, USA.

The number, size, and staining intensity of choline acetyltransferase (ChAT)-immunopositive cells in the retrodorsal lateral nucleus (RDLN) of the spinal cord were studied in young (3-5 months old) and aged (22-24 months old) rats following left sciatic nerve distal transection (axotomy) and treatment with GM1 ganglioside. The cell size and the ChAT immunostaining density were decreased in the RDLN of non-manipulated as well as in the contralateral intact side of axotomized aged rats. Axotomy had no effect on the number of RDLN motoneurons in both aged and young rats. In the young rats, there was a decrease in the size of motoneurons 7 days post-axotomy and a partial spontaneous recovery occurred by 21 days. Axotomy did not reduce further the size of aged motoneurons, however. The ChAT staining intensity of the axotomized RDLN declined in both age groups after 7 days, and there was spontaneous near normal recovery by 21 days. In the aged rats, GM1 administration for 7 days corrected the cell size and ChAT immunoreactivity of the contralateral intact RDLN. With regard to axotomized RDLN neurons, 7 days of GM1 restored the cell size but not the ChAT immunostaining in young animals. The same treatment schedule, however, corrected both cell size and staining in aged rats. Administration of GM1 for 21 days had no further effect on the morphometric parameters of the axotomized motoneurons in aged rats, but slightly enhanced the recovery of ChAT immunostaining in young rats. Thus, it appears that GM1 facilitates the phenotypic recovery of RDLN motoneurons during aging and after axotomy.
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http://dx.doi.org/10.1016/s0006-8993(02)04247-6DOI Listing
April 2003

Upregulation of FGF-2 in reactive spinal cord astrocytes following unilateral lumbar spinal nerve ligation.

Exp Brain Res 2003 Feb 26;148(3):366-76. Epub 2002 Nov 26.

Department of Internal Medicine, The Ohio State University, William H. Davis Medical Research Center, 480 W. 9th Avenue, Columbus, OH 43210, USA.

Spinal nerve ligation results in dramatic changes in spinal cord primary C-afferent fibers, which include atrophy with an accompanied decrease in calcitonin-gene-related peptide (CGRP). These changes parallel the activation of astrocytes, which have been implicated in the ensuing neuropathic pain states. As part of an effort to elucidate the role of the downstream effectors of astrocyte reactivity in the context of allodynia, the expression of fibroblast growth factor-2 (FGF-2) was examined following tight ligation of L5 and L6 spinal nerves. FGF-2 is a pleiotropic cytokine that is synthesized and secreted by neurons and astrocytes. FGF-2 immunoreactivity was increased in ipsilateral dorsal horn reactive astrocytes at 1 and 3 weeks following nerve ligation. Semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) of laser-captured dorsal spinal cord sections revealed an increase in FGF-2 mRNA in the dorsal horn ipsilateral to nerve injury compared to contralateral and SHAM. Furthermore, an increase in FGF-2 mRNA in ispilateral dorsal root ganglia (DRG) was seen by in situ hybridization. These results demonstrate that, in response to ligation-induced injury of sensory neurons, FGF-2 is upregulated in both DRG neurons and in spinal cord astrocytes, suggesting neurotrophic functions of this growth factor following peripheral nerve lesion and possibly in astrocyte-related maintenance of pain states.
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http://dx.doi.org/10.1007/s00221-002-1286-3DOI Listing
February 2003

Reduced basal release of serotonin from the ventrobasal thalamus of the rat in a model of neuropathic pain.

Pain 2002 Sep;99(1-2):359-66

Department of Physiology and Cell Biology, College of Medicine and Public Health, The Ohio State University, 304 Hamilton Hall, 1645 Neil Avenue, College of Medicine and Public Health, Columbus, OH 43210, USA.

Drugs that inhibit reuptake of monoamines are frequently used to treat pain syndromes, e.g. neuropathy or fibromyalgia, where mechanical allodynia is present. Several lines of evidence suggest the involvement of supraspinal sites of action of these drugs. However, a direct study of supraspinal serotonin (5-HT) or norepinephrine (NE) release in an animal model in which allodynia is expressed, e.g. neuropathy, has not been done. The ventrobasal (VB) thalamus and the hypothalamus are major supraspinal projection regions for spinal neurons that transmit nociceptive information and are innervated by monoaminergic fibers. This study determined if peripheral neuropathy would induce changes in extracellular monoamines in VB thalamus and hypothalamus. Male Sprague-Dawley rats had spinal nerve roots L5 and L6 tightly ligated (neuropathic rats; NP) or sham (SHAM) surgery; contralateral and ipsilateral VB thalamus and contralateral hypothalamus were dialyzed with modified artificial cerebral spinal fluid (aCSF), with and without fluoxetine. NP rats had significantly decreased 5-HT content in dialysates of the contralateral VB thalamus compared with SHAM rats with (82% decrease) or without (63% decrease) fluoxetine in the perfusion medium over the 180 min of the study. There were no differences in the ipsilateral VB thalamus. In contrast, release of 5-HT was unchanged in the hypothalamic dialysates of SHAM vs. NP rats. NE release was not different in dialysates of either the VB thalamus or hypothalamus of SHAM vs. NP rats. Synthesis of 5-HT, as assessed by accumulation of 5-hydroxytrytophan after treatment with an L-amino acid decarboxylase inhibitor, was not different between NP and SHAM rats in VB thalamic and hypothalamic brain tissue. This study is the first to demonstrate changes in monoamine release supraspinally in NP rats. The differential effect between VB thalamus and hypothalamus suggests that a terminal field change may be involved. Putative mechanisms for mediating this change include alterations of GABA-ergic systems and/or plasticity related to alterations in N-methyl-D-aspartate receptor activation and nitric oxide release related to afferent hyperactivity induced by neuropathic pain.
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http://dx.doi.org/10.1016/s0304-3959(02)00209-9DOI Listing
September 2002