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Chun J, Brinkmann V. A mechanistically novel, first oral therapy for multiple sclerosis: the development of fingolimod (FTY720, Gilenya). DISCOVERY MEDICINE 2011; 12:213-28. [PMID: 21955849 PMCID: PMC3694567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Multiple sclerosis (MS) is a chronic autoimmune disorder affecting the central nervous system (CNS) through demyelination and neurodegeneration. Until recently, major therapeutic treatments have relied on agents requiring injection delivery. In September 2010, fingolimod/FTY720 (Gilenya, Novartis) was approved by the FDA as the first oral treatment for relapsing forms of MS. Fingolimod is a novel compound produced by chemical modification of a fungal precursor. Its active metabolite, formed by in vivo phosphorylation, modulates sphingosine 1-phosphate (S1P) receptors that are a subset of a larger family of cell-surface, G protein-coupled receptors (GPCRs) mediating the effects of bioactive lipids known as lysophospholipids. Fingolimod's mechanism of action in MS is not completely understood; however, its relevant biology indicates a fundamentally different mechanism compared to all previously approved MS therapies, with evolving research supporting both immunological and nervous system activities. This duality may herald a paradigm shift in the treatment of MS and other neurological disorders.
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Gennero I, Laurencin-Dalicieux S, Conte-Auriol F, Briand-Mésange F, Laurencin D, Rue J, Beton N, Malet N, Mus M, Tokumura A, Bourin P, Vico L, Brunel G, Oreffo ROC, Chun J, Salles JP. Absence of the lysophosphatidic acid receptor LPA1 results in abnormal bone development and decreased bone mass. Bone 2011; 49:395-403. [PMID: 21569876 PMCID: PMC3697734 DOI: 10.1016/j.bone.2011.04.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 04/07/2011] [Accepted: 04/20/2011] [Indexed: 11/18/2022]
Abstract
Lysophosphatidic acid (LPA) is a lipid mediator that acts in paracrine systems via interaction with a subset of G protein-coupled receptors (GPCRs). LPA promotes cell growth and differentiation, and has been shown to be implicated in a variety of developmental and pathophysiological processes. At least 6 LPA GPCRs have been identified to date: LPA1-LPA6. Several studies have suggested that local production of LPA by tissues and cells contributes to paracrine regulation, and a complex interplay between LPA and its receptors, LPA1 and LPA4, is believed to be involved in the regulation of bone cell activity. In particular, LPA1 may activate both osteoblasts and osteoclasts. However, its role has not as yet been examined with regard to the overall status of bone in vivo. We attempted to clarify this role by defining the bone phenotype of LPA1((-/-)) mice. These mice demonstrated significant bone defects and low bone mass, indicating that LPA1 plays an important role in osteogenesis. The LPA1((-/-)) mice also presented growth and sternal and costal abnormalities, which highlights the specific roles of LPA1 during bone development. Microcomputed tomography and histological analysis demonstrated osteoporosis in the trabecular and cortical bone of LPA1((-/-)) mice. Finally, bone marrow mesenchymal progenitors from these mice displayed decreased osteoblastic differentiation. These results suggest that LPA1 strongly influences bone development both qualitatively and quantitatively and that, in vivo, its absence results in decreased osteogenesis with no clear modification of osteoclasis. They open perspectives for a better understanding of the role of the LPA/LPA1 paracrine pathway in bone pathophysiology.
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Trimbuch T, Beed P, Vogt J, Schuchmann S, Maier N, Kintscher M, Breustedt J, Schuelke M, Streu N, Kieselmann O, Brunk I, Laube G, Strauss U, Battefeld A, Wende H, Birchmeier C, Wiese S, Sendtner M, Kawabe H, Kishimoto-Suga M, Brose N, Baumgart J, Geist B, Aoki J, Savaskan N, Bräuer A, Chun J, Ninnemann O, Schmitz D, Nitsch R. Synaptic PRG-1 Modulates Excitatory Transmission via Lipid Phosphate-Mediated Signaling. Cell 2011. [DOI: 10.1016/j.cell.2011.08.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Zhao J, He D, Su Y, Berdyshev E, Chun J, Natarajan V, Zhao Y. Lysophosphatidic acid receptor 1 modulates lipopolysaccharide-induced inflammation in alveolar epithelial cells and murine lungs. Am J Physiol Lung Cell Mol Physiol 2011; 301:L547-56. [PMID: 21821728 DOI: 10.1152/ajplung.00058.2011] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Lysophosphatidic acid (LPA), a bioactive phospholipid, plays an important role in lung inflammation by inducing the release of chemokines and lipid mediators. Our previous studies have shown that LPA induces the secretion of interleukin-8 and prostaglandin E(2) in lung epithelial cells. Here, we demonstrate that LPA receptors contribute to lipopolysaccharide (LPS)-induced inflammation. Pretreatment with LPA receptor antagonist Ki16425 or downregulation of LPA receptor 1 (LPA(1)) by small-interfering RNA (siRNA) attenuated LPS-induced phosphorylation of p38 MAPK, I-κB kinase, and I-κB in MLE12 epithelial cells. In addition, the blocking of LPA(1) also suppressed LPS-induced IL-6 production. Furthermore, LPS treatment promoted interaction between LPA(1) and CD14, a LPS coreceptor, in a time- and dose-dependent manner. Disruption of lipid rafts attenuated the interaction between LPA(1) and CD14. Mice challenged with LPS increased plasma LPA levels and enhanced expression of LPA receptors in lung tissues. To further investigate the role of LPA receptors in LPS-induced inflammation, wild-type, or LPA(1)-deficient mice, or wild-type mice pretreated with Ki16425 were intratracheally challenged with LPS for 24 h. Knock down or inhibition of LPA(1) decreased LPS-induced IL-6 release in bronchoalveolar lavage (BAL) fluids and infiltration of cells into alveolar space compared with wild-type mice. However, no significant differences in total protein concentration in BAL fluids were observed. These results showed that knock down or inhibition of LPA(1) offered significant protection against LPS-induced lung inflammation but not against pulmonary leak as observed in the murine model for lung injury.
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Castelino FV, Seiders J, Bain G, Brooks SF, King CD, Swaney JS, Lorrain DS, Chun J, Luster AD, Tager AM. Amelioration of dermal fibrosis by genetic deletion or pharmacologic antagonism of lysophosphatidic acid receptor 1 in a mouse model of scleroderma. ACTA ACUST UNITED AC 2011; 63:1405-15. [PMID: 21305523 DOI: 10.1002/art.30262] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Scleroderma (systemic sclerosis [SSc]), is characterized by progressive multiorgan fibrosis. We recently implicated lysophosphatidic acid (LPA) in the pathogenesis of pulmonary fibrosis. The purpose of the present study was to investigate the roles of LPA and two of its receptors, LPA₁ and LPA₂, in dermal fibrosis in a mouse model of SSc. METHODS Wild type (WT), and LPA₁-knockout (KO) and LPA₂-KO mice were injected subcutaneously with bleomycin or phosphate buffered saline (PBS) once daily for 28 days. Dermal thickness, collagen content, and numbers of cells positive for α-smooth muscle actin (α-SMA) or phospho-Smad2 were determined in bleomycin-injected and PBS-injected skin. In separate experiments, a novel selective LPA₁ antagonist AM095 or vehicle alone was administered by oral gavage to C57BL/6 mice that were challenged with 28 daily injections of bleomycin or PBS. AM095 or vehicle treatments were initiated concurrently with, or 7 or 14 days after, the initiation of bleomycin and PBS injections and continued to the end of the experiments. Dermal thickness and collagen content were determined in injected skin. RESULTS The LPA₁ -KO mice were markedly resistant to bleomycin-induced increases in dermal thickness and collagen content, whereas the LPA₂-KO mice were as susceptible as the WT mice. Bleomycin-induced increases in dermal α-SMA+ and phospho-Smad2+ cells were abrogated in LPA₁-KO mice. Pharmacologic antagonism of LPA₁ with AM095 significantly attenuated bleomycin-induced dermal fibrosis when administered according to either a preventive regimen or two therapeutic regimens. CONCLUSION These results suggest that LPA/LPA₁ pathway inhibition has the potential to be an effective new therapeutic strategy for SSc, and that LPA₁ is an attractive pharmacologic target in dermal fibrosis.
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Cohen JA, Chun J. Mechanisms of fingolimod's efficacy and adverse effects in multiple sclerosis. Ann Neurol 2011; 69:759-77. [PMID: 21520239 DOI: 10.1002/ana.22426] [Citation(s) in RCA: 280] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Until recently, all approved multiple sclerosis (MS) disease treatments were administered parenterally. Oral fingolimod was approved in September 2010 by the US Food and Drug Administration to reduce relapses and disability progression in relapsing forms of MS. In the clinical trials that led to approval, fingolimod reduced not only acute relapses and magnetic resonance imaging lesion activity but also disability progression and brain volume loss, suggesting preservation of tissue. Fingolimod's mechanism of action in MS is not known with certainty. Its active form, fingolimod-phosphate (fingolimod-P), is a sphingosine 1-phosphate receptor (S1PR) modulator that inhibits egress of lymphocytes from lymph nodes and their recirculation, potentially reducing trafficking of pathogenic cells into the central nervous system (CNS). Fingolimod also readily penetrates the CNS, and fingolimod-P formed in situ may have direct effects on neural cells. Fingolimod potently inhibits the MS animal model, experimental autoimmune encephalomyelitis, but is ineffective in mice with selective deficiency of the S1P₁ S1PR subtype on astrocytes despite normal expression in the immune compartment. These findings suggest that S1PR modulation by fingolimod in both the immune system and CNS, producing a combination of beneficial anti-inflammatory and possibly neuroprotective/reparative effects, may contribute to its efficacy in MS. In clinical trials, fingolimod was generally safe and well tolerated. Its interaction with S1PRs in a variety of tissues largely accounts for the reported adverse effects, which were seen more frequently with doses 2.5 to 10x the approved 0.5 mg dose. Fingolimod's unique mechanism of action distinguishes it from all other currently approved MS therapies.
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Zhou Z, Subramanian P, Sevilmis G, Globke B, Soehnlein O, Karshovska E, Megens R, Heyll K, Chun J, Saulnier-Blache JS, Reinholz M, van Zandvoort M, Weber C, Schober A. Lipoprotein-derived lysophosphatidic acid promotes atherosclerosis by releasing CXCL1 from the endothelium. Cell Metab 2011; 13:592-600. [PMID: 21531341 DOI: 10.1016/j.cmet.2011.02.016] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 12/19/2010] [Accepted: 02/28/2011] [Indexed: 11/16/2022]
Abstract
Oxidatively modified low-density lipoprotein (oxLDL) plays a key role in the initiation of atherosclerosis by increasing monocyte adhesion. The mechanism that is responsible for the oxLDL-induced atherogenic monocyte recruitment in vivo, however, still remains unknown. Oxidation of LDL generates lysophosphatidylcholine, which is the main substrate for the lysophosphatidic acid (LPA) generating enzyme autotaxin. We show that oxLDL requires endothelial LPA receptors and autotaxin to elicit CXCL1-dependent arterial monocyte adhesion. Unsaturated LPA releases endothelial CXCL1, which is subsequently immobilized on the cell surface and mediates LPA-induced monocyte adhesion. Local and systemic application of LPA accelerates the progression of atherosclerosis in mice. Blocking the LPA receptors LPA(1) and LPA(3) reduced hyperlipidemia-induced arterial leukocyte arrest and atherosclerosis in the presence of functional CXCL1. Thus, atherogenic monocyte recruitment mediated by hyperlipidemia and modified LDL crucially depends on LPA, which triggers endothelial deposition of CXCL1, revealing LPA signaling as a target for cardiovascular disease treatments.
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Zhao C, Sardella A, Chun J, Poubelle PE, Fernandes MJ, Bourgoin SG. TNF-alpha promotes LPA1- and LPA3-mediated recruitment of leukocytes in vivo through CXCR2 ligand chemokines. J Lipid Res 2011; 52:1307-18. [PMID: 21521824 DOI: 10.1194/jlr.m008045] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Lysophosphatidic acid (LPA) is a bioactive lysophospholipid present in low concentrations in serum and biological fluids but in high concentrations at sites of inflammation. LPA evokes a variety of cellular responses via binding to and activation of its specific G protein-coupled receptors (GPCR), namely LPA(1-6). Even though LPA is a chemoattractant for inflammatory cells in vitro, such a role for LPA in vivo remains largely unexplored. In the present study, we used the murine air pouch model to study LPA-mediated leukocyte recruitment in vivo using selective LPA receptor agonist/antagonist and LPA(3)-deficient mice. We report that 1) LPA injection into the air pouch induced leukocyte recruitment and that both LPA(1) and LPA(3) were involved in this process; 2) LPA stimulated the release of the pro-inflammatory chemokines keratinocyte-derived chemokine (KC) and interferon-inducible protein-10 (IP-10) in the air pouch; 3) tumor necrosis factor-α (TNF-α) injected into the air pouch prior to LPA strongly potentiated LPA-mediated secretion of cytokines/chemokines, including KC, IL-6, and IP-10, which preceded the enhanced leukocyte influx; and 4) blocking CXCR2 significantly reduced leukocyte infiltration. We suggest that LPA, via LPA(1) and LPA(3) receptors, may play a significant role in inducing and/or sustaining the massive infiltration of leukocytes during inflammation.
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Hopson KP, Truelove J, Chun J, Wang Y, Waeber C. S1P activates store-operated calcium entry via receptor- and non-receptor-mediated pathways in vascular smooth muscle cells. Am J Physiol Cell Physiol 2011; 300:C919-26. [PMID: 21270296 PMCID: PMC3074633 DOI: 10.1152/ajpcell.00350.2010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 01/24/2011] [Indexed: 10/18/2022]
Abstract
Sphingosine-1-phosphate (S1P) has been shown to modulate intracellular Ca(2+) through both G protein-coupled receptors and intracellular second messenger pathways. The precise mechanism by which S1P activates store-operated calcium entry (SOCE) in vascular smooth muscle cells (VSMCs) has not been fully characterized. Because sphingolipids and Ca(2+) modulate proliferation and constriction in VSMCs, characterizing the connection between S1P and SOCE may provide novel therapeutic targets for vascular diseases. We found that S1P triggered STIM1 puncta formation and SOCE in VSMCs. S1P-activated SOCE was inhibited by 2-aminoethoxydiphenyl borate (2-APB), diethylstilbestrol (DES), and gadolinium (Gd(3+)). SOCE was observed in VSMCs lacking either S1P(2) or S1P(3) receptors, suggesting that S1P acts via multiple signaling pathways. Indeed, both extracellular and intracellular S1P application increased the total internal reflection fluorescence signal in VSMCs cells transfected with STIM1-yellow fluorescent protein in a 2-APB-sensitive manner. These data, and the fact that 2-APB, DES, and Gd(3+) all inhibited S1P-induced cerebral artery constriction, suggest that SOCE modulates S1P-induced vasoconstriction in vivo. Finally, S1P-induced SOCE was larger in proliferative than in contractile VSMCs, correlating with increases in STIM1, Orai1, S1P(1), and S1P(3) receptor mRNA. These data demonstrate that S1P can act through both receptors and a novel intracellular pathway to activate SOCE. Because S1P-induced SOCE contributes to vessel constriction and is increased in proliferative VSMCs, it is likely that S1P/SOCE signaling in proliferative VSMCs may play a role in vascular dysfunction such as atherosclerosis and diabetes.
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Soliven B, Miron V, Chun J. The neurobiology of sphingosine 1-phosphate signaling and sphingosine 1-phosphate receptor modulators. Neurology 2011; 76:S9-14. [PMID: 21339490 DOI: 10.1212/wnl.0b013e31820d9507] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Sphingosine 1-phosphate receptors (S1PRs) are G protein-coupled receptors expressed by many cell types, including immune and neural cells. These receptors are promising targets for immunomodulatory and possibly neuromodulatory therapies. Fingolimod (FTY720) is a sphingosine analog that, when phosphorylated, becomes a prototypical S1PR modulator. It has recently been approved as the first oral treatment for relapsing forms of multiple sclerosis in some countries. Fingolimod has documented effects on lymphocyte egress, selectively retaining lymphocytes within the lymph nodes. In addition, fingolimod can enter the CNS and can act on S1PRs expressed by most neural lineages. In this article, we discuss recent results supporting the concept that S1PR modulators may exert neuroprotective and regenerative actions in the CNS as well as having anti-inflammatory effects.
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Abstract
Human pluripotent stem cells (PSCs) hold promise for treating a multitude of diseases. These fascinating cells are unique in their ability to both self-renew and differentiate into cells from all three germ layers. However, PSCs, as well as other cultured cells, are prone to genetic instability. Given the possibility that these cells may one day be used clinically, identifying, and perhaps preventing, genetic instability is of particular concern for human PSC researchers. One type of genetic alteration that has been observed in PSCs is aneuploidy. Aneuploidy is defined as any divergence from the normal diploid number of chromosomes. So for human cells, any cell with more or less than 46 chromosomes would be considered aneuploid. Interestingly, there is a tendency for human PSCs, regardless of culture conditions, to gain specific chromosomes. In particular, gains of chromosomes 12, 17, 1, and X have been reported from labs all over the world. Since gains of these specific chromosomes are by far the most common aneuploidy seen in human PSCs, it is relatively easy and inexpensive to screen for these using fluorescent in situ hybridization (FISH). Here we will describe a cytogenetic method for screening human PSCs using FISH.
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Checka C, Chun J, Schnabel F, Guth A, Axelrod D, Roses D. Abstract P2-01-02: The Incidence of Mammographically-Occult Breast Cancer in Women Older than Seventy Years. Cancer Res 2010. [DOI: 10.1158/0008-5472.sabcs10-p2-01-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Mammographic density generally decreases over time, which increases the sensitivity of screening mammography. However a significant proportion of older women have persistently dense breast tissue. This raises the question of how best to screen older women, particularly those with mammographically dense tissue or other risk factors. Little information exists about the accuracy of screening mammography in women older than seventy years. Additionally, the frequency of older women with mammographically-occult breast cancer is also unknown. The purpose of this study was to report the incidence of mammographicallyoccult breast cancer in women older than seventy and to describe the clinical factors that may be associated with this presentation.
Methods:
A retrospective chart review was conducted of women older than seventy diagnosed with breast cancer (intraductal carcinoma, invasive ductal carcinoma and invasive lobular carcinoma) at NYU Langone Medical Center from 2002-2009. Data collected included age, presentation, stage, mammographic density, BI-RADS results, breast ultrasound (US) and MRI results, and risk factors. Breast density was categorized according to BI-RADS definitions: 1. predominantly fatty, 2. scattered fibroglandular elements, 3. heterogeneously dense, or 4. extremely dense. Descriptive analyses were applied.
Results: A total of 401 women older than seventy years were diagnosed with breast cancer at our institution. A cohort of 20 (5%) had mammographically occult disease. The median age was 77 years (range 71 to 89 yrs). Of the 20 mammographically occult cases, the majority (75%) were detected as a palpable mass, one was detected by screening US and four were detected by screening MRI. The majority of the cohort (65%) had been screened regularly with mammography prior to diagnosis. When we examined mammographic density, 60% had heterogeneously dense or extremely dense tissue. Nineteen out of twenty were diagnosed with early stage disease. There were 4 cases of DCIS, 10 (50%) were stage 1, and 5 (25%) were stage 2. Seven (35%) had invasive lobular carcinoma on final histopathology. Nine (45%) patients also had an antecedent history of breast cancer; 4 had ipsilateral recurrences and 5 had contralateral new primaries. Only 4 (20%) had a history of HRT use and 7 (35%) had a family history of breast cancer.
Discussion: A meaningful proportion of women older than age seventy diagnosed with breast cancer at our institution had mammographicallyoccult disease. A majority (60%) of these patients had heterogeneously dense or extremely dense breast tissue, potentially limiting the sensitivity of mammographic screening in this cohort. In previous work, we evaluated a large number of screening mammograms and reported an incidence of 37% dense breast tissue in women of the same age group. This suggests that increased mammographic density, even in older women, may increase the potential for mammographically occult breast cancer. Particularly for women with increased risk based on a personal or family history of breast cancer, the addition of other imaging modalities may be of value in the presence of mammographically dense tissue regardless of patient age.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-01-02.
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Westra JW, Rivera RR, Bushman DM, Yung YC, Peterson SE, Barral S, Chun J. Neuronal DNA content variation (DCV) with regional and individual differences in the human brain. J Comp Neurol 2010; 518:3981-4000. [PMID: 20737596 DOI: 10.1002/cne.22436] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is widely assumed that the human brain contains genetically identical cells through which postgenomic mechanisms contribute to its enormous diversity and complexity. The relatively recent identification of neural cells throughout the neuraxis showing somatically generated mosaic aneuploidy indicates that the vertebrate brain can be genomically heterogeneous (Rehen et al. [2001] Proc. Natl. Acad. Sci. U. S. A. 98:13361-13366; Rehen et al. [2005] J. Neurosci. 25:2176-2180; Yurov et al. [2007] PLoS ONE:e558; Westra et al. [2008] J. Comp. Neurol. 507:1944-1951). The extent of human neural aneuploidy is currently unknown because of technically limited sample sizes, but is reported to be small (Iourov et al. [2006] Int. Rev. Cytol. 249:143-191). During efforts to interrogate larger cell populations by using DNA content analyses, a surprising result was obtained: human frontal cortex brain cells were found to display "DNA content variation (DCV)" characterized by an increased range of DNA content both in cell populations and within single cells. On average, DNA content increased by approximately 250 megabases, often representing a substantial fraction of cells within a given sample. DCV within individual human brains showed regional variation, with increased prevalence in the frontal cortex and less variation in the cerebellum. Further, DCV varied between individual brains. These results identify DCV as a new feature of the human brain, encompassing and further extending genomic alterations produced by aneuploidy, which may contribute to neural diversity in normal and pathophysiological states, altered functions of normal and disease-linked genes, and differences among individuals.
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Chun J, Hla T, Lynch KR, Spiegel S, Moolenaar WH. International Union of Basic and Clinical Pharmacology. LXXVIII. Lysophospholipid receptor nomenclature. Pharmacol Rev 2010; 62:579-87. [PMID: 21079037 PMCID: PMC2993255 DOI: 10.1124/pr.110.003111] [Citation(s) in RCA: 246] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Lysophospholipids are cell membrane-derived lipids that include both glycerophospholipids such as lysophosphatidic acid (LPA) and sphingoid lipids such as sphingosine 1-phosphate (S1P). These and related molecules can function in vertebrates as extracellular signals by binding and activating G protein-coupled receptors. There are currently five LPA receptors, along with a proposed sixth (LPA₁-LPA₆), and five S1P receptors (S1P₁-S1P₅). A remarkably diverse biology and pathophysiology has emerged since the last review, driven by cloned receptors and targeted gene deletion ("knockout") studies in mice, which implicate receptor-mediated lysophospholipid signaling in most organ systems and multiple disease processes. The entry of various lysophospholipid receptor modulatory compounds into humans through clinical trials is ongoing and may lead to new medicines that are based on this signaling system. This review incorporates IUPHAR Nomenclature Committee guidelines in updating the nomenclature for lysophospholipid receptors ( http://www.iuphar-db.org/DATABASE/FamilyMenuForward?familyId=36).
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Nagai J, Uchida H, Matsushita Y, Yano R, Ueda M, Niwa M, Aoki J, Chun J, Ueda H. Autotaxin and lysophosphatidic acid1 receptor-mediated demyelination of dorsal root fibers by sciatic nerve injury and intrathecal lysophosphatidylcholine. Mol Pain 2010; 6:78. [PMID: 21062487 PMCID: PMC2989310 DOI: 10.1186/1744-8069-6-78] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 11/09/2010] [Indexed: 12/15/2022] Open
Abstract
Background Although neuropathic pain is frequently observed in demyelinating diseases such as Guillain-Barré syndrome and multiple sclerosis, the molecular basis for the relationship between demyelination and neuropathic pain behaviors is poorly understood. Previously, we found that lysophosphatidic acid receptor (LPA1) signaling initiates sciatic nerve injury-induced neuropathic pain and demyelination. Results In the present study, we have demonstrated that sciatic nerve injury induces marked demyelination accompanied by myelin-associated glycoprotein (MAG) down-regulation and damage of Schwann cell partitioning of C-fiber-containing Remak bundles in the sciatic nerve and dorsal root, but not in the spinal nerve. Demyelination, MAG down-regulation and Remak bundle damage in the dorsal root were abolished in LPA1 receptor-deficient (Lpar1-/-) mice, but these alterations were not observed in sciatic nerve. However, LPA-induced demyelination in ex vivo experiments was observed in the sciatic nerve, spinal nerve and dorsal root, all which express LPA1 transcript and protein. Nerve injury-induced dorsal root demyelination was markedly attenuated in mice heterozygous for autotaxin (atx+/-), which converts lysophosphatidylcholine (LPC) to LPA. Although the addition of LPC to ex vivo cultures of dorsal root fibers in the presence of recombinant ATX caused potent demyelination, it had no significant effect in the absence of ATX. On the other hand, intrathecal injection of LPC caused potent dorsal root demyelination, which was markedly attenuated or abolished in atx+/- or Lpar1-/- mice. Conclusions These results suggest that LPA, which is converted from LPC by ATX, activates LPA1 receptors and induces dorsal root demyelination following nerve injury, which causes neuropathic pain.
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Lin S, Lee SJ, Shim H, Chun J, Yun CC. The absence of LPA receptor 2 reduces the tumorigenesis by ApcMin mutation in the intestine. Am J Physiol Gastrointest Liver Physiol 2010; 299:G1128-38. [PMID: 20724530 PMCID: PMC2993170 DOI: 10.1152/ajpgi.00321.2010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Lysophosphatidic acid (LPA) is a lipid mediator that mediates several effects that promote cancer progress. The LPA receptor type 2 (LPA(2)) expression is often elevated in several types of cancers, including colorectal cancer (CRC). In this study, we investigated the role of LPA(2) in the development of intestinal adenomas by comparing Apc(Min/+) mice with Apc(Min/+)/Lpar2(-/-) mice. There were 50% fewer intestinal adenomas in Apc(Min/+)/Lpar2(-/-) mice than Apc(Min/+) mice. Smaller-size adenomas (<1 mm) were found at higher frequencies in Apc(Min/+)/Lpar2(-/-) mice compared with Apc(Min/+) mice at the two age groups examined. The expression level of LPA(2) correlated with increased size of intestinal adenomas. Reduced tumor multiplicity and size in Apc(Min/+)/Lpar2(-/-) mice correlated with decreased proliferation of intestinal epithelial cells. Apc(Min/+)/Lpar2(-/-) mice showed an increased level of apoptosis, suggesting that LPA(2)-mediated signaling stimulates intestinal tumor development and progress by regulating both cell proliferation and survival. In addition, the expression levels of Krüpple-like factor 5 (KLF5), β-catenin, cyclin D1, c-Myc, and hypoxia-inducible factor-1α (HIF-1α) were significantly altered in Apc(Min/+)/Lpar2(-/-) mice compared with Apc(Min/+) mice. In vitro studies using HCT116 cells showed that LPA induced cyclin D1, c-Myc, and HIF-1α expression, which was attenuated by knockdown of LPA(2). In summary, intestinal tumor initiated by Apc mutations is altered by LPA(2)-mediated signaling, which regulates tumor growth and survival by altering multiple targets.
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Lee CW, Choi JW, Chun J. Neurological S1P signaling as an emerging mechanism of action of oral FTY720 (fingolimod) in multiple sclerosis. Arch Pharm Res 2010; 33:1567-74. [PMID: 21052934 DOI: 10.1007/s12272-010-1008-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2010] [Revised: 08/23/2010] [Accepted: 08/24/2010] [Indexed: 12/01/2022]
Abstract
FTY720 (fingolimod, Novartis) is a promising investigational drug for relapsing forms of multiple sclerosis (MS), an autoimmune and neurodegenerative disorder of the central nervous system. It is currently under FDA review in the United States, and could represent the first approved oral treatment for MS. Extensive, ongoing clinical trials in Phase II/III have supported both the efficacy and safety of FTY720. FTY720 itself is not bioactive, but when phosphorylated (FTY720-P) by sphingosine kinase 2, it becomes active through modulation of 4 of the 5 known G protein-coupled sphingosine 1-phosphate (S1P) receptors. The mechanism of action (MOA) is thought to be immunological, where FTY720 alters lymphocyte trafficking via S1P1. However, MOA for FTY720 in MS may also involve a direct, neurological action within the central nervous system in view of documented S1P receptor-mediated signaling influences in the brain, and this review considers observations that support an emerging neurological MOA.
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Noguchi K, Chun J. Roles for lysophospholipid S1P receptors in multiple sclerosis. Crit Rev Biochem Mol Biol 2010; 46:2-10. [DOI: 10.3109/10409238.2010.522975] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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195
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Diao H, Aplin JD, Xiao S, Chun J, Li Z, Chen S, Ye X. Altered spatiotemporal expression of collagen types I, III, IV, and VI in Lpar3-deficient peri-implantation mouse uterus. Biol Reprod 2010; 84:255-65. [PMID: 20864640 DOI: 10.1095/biolreprod.110.086942] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Lpar3 is upregulated in the preimplantation uterus, and deletion of Lpar3 leads to delayed uterine receptivity in mice. Microarray analysis revealed that there was higher expression of Col3a1 and Col6a3 in the Preimplantation Day 3.5 Lpar3(-/-) uterus compared to Day 3.5 wild-type (WT) uterus. Since extracellular matrix (ECM) remodeling is indispensable during embryo implantation, and dynamic spatiotemporal alteration of specific collagen types is part of this process, this study aimed to characterize the expression of four main uterine collagen types: fibril-forming collagen (COL) I and COL III, basement membrane COL IV, and microfibrillar COL VI in the peri-implantation WT and Lpar3(-/-) uterus. An observed delay of COL III and COL VI clearance in the Lpar3(-/-) uterus may be associated with higher preimplantation expression of Col3a1 and Col6a3. There was also delayed clearance of COL I and delayed deposition of COL IV in the decidual zone in the Lpar3(-/-) uterus. These changes were different from the effects of 17beta-estradiol and progesterone on uterine collagen expression in ovariectomized WT uterus, indicating that the altered collagen expression in Lpar3(-/-) uterus is unlikely to be a result of alterations in ovarian hormones. Decreased expression of several genes encoding matrix-degrading metallo- and serine proteinases was observed in the Lpar3(-/-) uterus. These results demonstrate that pathways downstream of LPA3 are involved in the dynamic remodeling of ECM in the peri-implantation uterus.
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196
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Yoon HJ, Chun J, Kim JH, Kang SS, Na DJ. Gardnerella vaginalis septicaemia with pyelonephritis, infective endocarditis and septic emboli in the kidney and brain of an adult male. Int J STD AIDS 2010; 21:653-7. [DOI: 10.1258/ijsa.2010.009574] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Gardnerella vaginalis is typically associated with bacterial vaginosis in women. However, balanitis, urethritis, urinary tract infections and asymptomatic bacteraemia have also been described in men. Here we report a case of G. vaginalis septicaemia with infective endocarditis and septic emboli in the kidney and brain of an adult male.
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197
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Labeda DP, Goodfellow M, Chun J, Zhi XY, Li WJ. Reassessment of the systematics of the suborder Pseudonocardineae: transfer of the genera within the family Actinosynnemataceae Labeda and Kroppenstedt 2000 emend. Zhi et al. 2009 into an emended family Pseudonocardiaceae Embley et al. 1989 emend. Zhi et al. 2009. Int J Syst Evol Microbiol 2010; 61:1259-1264. [PMID: 20601483 DOI: 10.1099/ijs.0.024984-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The taxonomic status of the families Actinosynnemataceae and Pseudonocardiaceae was assessed based on 16S rRNA gene sequence data available for the 151 taxa with validly published names, as well as chemotaxonomic and morphological properties available from the literature. 16S rRNA gene sequences for the type strains of all taxa within the suborder Pseudonocardineae were subjected to phylogenetic analyses using different algorithms in arb and phylip. The description of many new genera and species within the suborder Pseudonocardineae since the family Actinosynnemataceae was proposed in 2000 has resulted in a markedly different distribution of chemotaxonomic markers within the suborder from that observed at that time. For instance, it is noted that species of the genera Actinokineospora and Allokutzneria contain arabinose in whole-cell hydrolysates, which is not observed in the other genera within the Actinosynnemataceae, and that there are many genera within the family Pseudonocardiaceae as currently described that do not contain arabinose. Phylogenetic analyses of 16S rRNA gene sequences for all taxa within the suborder do not provide any statistical support for the family Actinosynnemataceae, nor are signature nucleotides found that support its continued differentiation from the family Pseudonocardiaceae. The description of the family Pseudonocardiaceae is therefore emended to include the genera previously classified within the family Actinosynnemataceae and the description of the suborder Pseudonocardineae is also emended to reflect this reclassification.
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198
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Chun J, Kim W, Kim BG, Lee KL, Suh KS, Yi NJ, Park KU, Kim YJ, Yoon JH, Lee HS. High viremia, prolonged Lamivudine therapy and recurrent hepatocellular carcinoma predict posttransplant hepatitis B recurrence. Am J Transplant 2010; 10:1649-59. [PMID: 20642687 DOI: 10.1111/j.1600-6143.2010.03162.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Hepatitis B virus (HBV) recurrence following orthotopic liver transplantation (OLT) is generally preventable by prophylaxis with hepatitis B immunoglobulin (HBIG) and lamivudine (LAM). However, HBV recurrence sometimes develops despite prophylaxis. This study assessed posttransplant outcomes and identified predictors of HBV recurrence. We analyzed the outcomes of 209 consecutive patients positive for hepatitis B surface antigen who underwent OLT, who received either combination prophylaxis with HBIG and LAM (89.0%) or HBIG monoprophylaxis (11.0%). The median follow-up was 36.8 months (range, 1.0-84.4). Posttransplant HBV recurrence occurred in 22 patients (10.5%), including 13 patients with drug-resistant mutations. HBV recurrence was observed in six patients after hepatocellular carcinoma (HCC) recurrence. Independent predictors of HBV recurrence were recurrent HCC (p < 0.001), LAM therapy >1.5 years (p = 0.001) and high HBV DNA titers (> or =10(5) copies/mL) at OLT (p = 0.036). In conclusion, high viremia at OLT and prolonged exposure to LAM should be further stressed as main predictors of HBV recurrence.
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199
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Xie W, Uchida H, Nagai J, Ueda M, Chun J, Ueda H. Calpain-mediated down-regulation of myelin-associated glycoprotein in lysophosphatidic acid-induced neuropathic pain. J Neurochem 2010; 113:1002-11. [PMID: 20420580 DOI: 10.1111/j.1471-4159.2010.06664.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lysophosphatidic acid receptor (LPA(1)) signaling initiates neuropathic pain through demyelination of the dorsal root (DR). Although LPA is found to cause down-regulation of myelin proteins underlying demyelination, the detailed mechanism remains to be determined. In the present study, we found that a single intrathecal injection of LPA evoked a dose- and time-dependent down-regulation of myelin-associated glycoprotein (MAG) in the DR through LPA(1) receptor. A similar event was also observed in ex vivo DR cultures. Interestingly, LPA-induced down-regulation of MAG was significantly inhibited by calpain inhibitors (calpain inhibitor X, E-64 and E-64d) and LPA markedly induced calpain activation in the DR. The pre-treatment with calpain inhibitors attenuated LPA-induced neuropathic pain behaviors such as hyperalgesia and allodynia. Moreover, we found that sciatic nerve injury activates calpain activity in the DR in a LPA(1) receptor-dependent manner. The E-64d treatments significantly blocked nerve injury-induced MAG down-regulation and neuropathic pain. However, there was no significant calpain activation in the DR by complete Freund's adjuvant treatment, and E-64d failed to show anti-hyperalgesic effects in this inflammation model. The present study provides strong evidence that LPA-induced calpain activation plays a crucial role in the manifestation of neuropathic pain through MAG down-regulation in the DR.
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200
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Kim E, Cheong HS, Bae JS, Chun J, Park TJ, Lee K, Yun Y, Shin HD. Identification of genetic polymorphisms in bovine mitochondrial deoxyribonucleic acid. J Anim Sci 2010; 88:2551-5. [PMID: 20418455 DOI: 10.2527/jas.2009-2235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In this study, the intent was to identify genetic polymorphisms of mitochondrial (mt) DNA in Korean cattle (Bos taurus coreana) and to analyze the genetic relationship between Korean cattle and other breeds. Whole mtDNA genomes (16,338 bp) of 26 animals (16 Korean cattle and 10 Holsteins) were directly sequenced. Multiple alignments, including 26 whole-mtDNA sequences obtained by direct sequencing and 10 mtDNA sequences from a public database (National Center for Biotechnology Information), revealed 393 mtDNA polymorphisms (382 SNP, 3 heteroplasmies, and 8 insertion-deletion polymorphisms). Estimated gene diversity of mtDNA was 0.00198 among these 36 animals. Phylogenic analysis with mtDNA polymorphisms revealed a distinct genetic difference between Bos taurus (Korean, Japanese Black, Holstein, and Fleckvieh breeds) and Bos indicus (Nellore and Zwergzebu breeds). The genetic information regarding mtDNA polymorphisms identified in this study would be useful for further investigation of mtDNA in other breeds.
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