Richard A Mumford

Publications (31)79.5 Total impact

• Article: Aα-Val360: A Marker of Neutrophil Elastase and COPD Disease Activity.

  Richard I Carter, Michael J Ungurs, Richard A Mumford, Robert A Stockley
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  ABSTRACT: The FEV1 is currently the most widely used marker of COPD disease severity, however, it is a poor surrogate of the emphysematous component and the underlying pathophysiological mechanism and therefore new markers are urgently needed. Neutrophil elastase (NE) is likely to play a key pathophysiological role in COPD and the current study explores a marker of NE activity as a potential indicator of COPD disease activity.Aα-Val(360) was measured in 81 subjects with a clinical diagnosis of COPD, in the stable state and also at presentation with an acute exacerbation, and comparisons were made with lung function tests and CT imaging. The relationship of Aα-Val(360 )with disease progression was also assessed in 40 of the subjects over a 4 year period.Baseline Aα-Val(360 )related to physiological and radiological markers of disease severity, was higher at presentation with an acute exacerbation than in the stable state and (at least partly) related to disease progression over the subsequent 4 years.We demonstrate that Aα-Val(360 )is a marker of cross-sectional COPD disease severity and possibly disease progression, and represents a new concept of specific biomarkers. This study therefore reports the first in vivo data to support the pathophysiological role of NE in COPD.
  European Respiratory Journal 04/2012; · 5.89 Impact Factor
• Article: The fibrinogen cleavage product Aα-Val360, a specific marker of neutrophil elastase activity in vivo.

  Richard I Carter, Richard A Mumford, Kelly M Treonze, Paul E Finke, Phillip Davies, Qian Si, John L Humes, Asger Dirksen, Eeva Piitulainen, Ali Ahmad, Robert A Stockley
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  ABSTRACT: Alpha-1-antitrypsin (A1AT) deficiency is the only recognised genetic risk factor for chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality worldwide. Since A1AT is the major inhibitor of neutrophil elastase (NE), this enzyme has become widely implicated in the pathogenesis of COPD in general; however, there is currently no specific biomarker for its pre-inhibition activity. Such a biomarker should be a measure of elastase-specific COPD disease activity with the potential to assess early targeted therapeutic intervention, in contrast to traditional and non-specific disease severity markers such as forced expiratory volume in 1 s. In pilot studies, plasma Aα-Val(360) and markers of neutrophil activation were measured in 95 subjects with a range of A1AT concentrations. Aα-Val(360) and sputum elastase activity were also measured in a further seven PiZ A1AT-deficient subjects over the course of an acute exacerbation. Finally, Aα-Val(360) was measured in plasma from subjects randomised to receive A1AT replacement or placebo in the EXACTLE trial. The plasma concentrations of Aα-Val(360) and A1AT related exponentially, consistent with previous theoretical and in vitro experimental data. L-233 (an intracellular NE inhibitor) blocked generation of Aα-Val(360) and subsequent A1AT/NE complex formation. Aα-Val(360) was related to the spirometric severity of lung disease in A1AT deficiency, to sputum elastase activity in acute exacerbations and was decreased in subjects receiving A1AT replacement therapy (while remaining constant in those receiving placebo). Aα-Val(360) represents the first specific footprint of pre-inhibition NE activity and is a potential biomarker of disease activity and progression in subjects with elastase-dependent COPD. The EXACTLE study was registered in ClinicalTrials.gov as 'Antitrypsin (AAT) to Treat Emphysema in AAT-Deficient Patients'; ClinicalTrials.gov Identifier: NCT00263887.
  Thorax 05/2011; 66(8):686-91. · 6.84 Impact Factor
• Article: Heterocycle-substituted proline dipeptides as potent VLA-4 antagonists.

  Thomas S Reger, Jasmine Zunic, Nicholas Stock, Bowei Wang, Nicholas D Smith, Benito Munoz, Mitchell D Green, Michael F Gardner, Joyce P James, Weichao Chen, Kenneth Alves, Qian Si, Kelly M Treonze, Russell B Lingham, Richard A Mumford
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  ABSTRACT: A variety of N-linked tertiary amines and heteroarylamines were examined at the 4-position of sulfonylated proline dipeptides in order to improve VLA-4 receptor off-rates and overcome the issue of CYP3A4 time-dependent inhibition of ester prodrugs. A tight-binding inhibitor 5j with a long off-rate provided sustained receptor occupancy despite poor oral pharmacokinetics.
  Bioorganic & medicinal chemistry letters 12/2009; 20(3):1173-6. · 2.65 Impact Factor
• Article: Discovery of N-{N-[(3-cyanobenzene) sulfonyl]-4(R)-(3,3-difluoropiperidin-1-yl)-(l)-prolyl}-4-[(3',5'-dichloro-isonicotinoyl) amino]-(l)-phenylalanine (MK-0617), a highly potent and orally active VLA-4 antagonist.

  Shankar Venkatraman, Alec D Lebsack, Kenneth Alves, Michael F Gardner, Joyce James, Russell B Lingham, Salony Maniar, Richard A Mumford, Qian Si, Nicholas Stock, Kelly M Treonze, Bowei Wang, Jasmine Zunic, Benito Munoz
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  ABSTRACT: A series of prolyl-N-isonicotinoyl-(L)-4-aminophenylalanine derivatives substituted at the proline 4-position with cyclic amines was evaluated as VLA-4 antagonists. The ring size and presence or absence of fluorine affected potency and receptor occupancy. The analog with 3,3-difluoropiperidine at the proline 4-position (13) was the most potent compound and had very good duration of receptor occupancy in vitro. The ethyl ester prodrug of 13 demonstrated excellent receptor occupancy after oral dosing in rats.
  Bioorganic & medicinal chemistry letters 08/2009; 19(19):5803-6. · 2.65 Impact Factor
• Article: Discovery of N-{N-[(3-cyanophenyl)sulfonyl]-4(R)-cyclobutylamino-(L)-prolyl}-4-[(3',5'-dichloroisonicotinoyl) amino]-(L)-phenylalanine (MK-0668), an extremely potent and orally active antagonist of very late antigen-4.

  Linus S Lin, Thomas Lanza, James P Jewell, Ping Liu, Carrie Jones, Gerard R Kieczykowski, Kelly Treonze, Qian Si, Salony Manior, Gloria Koo, [......], Junying Wang, Anne Schuelke, James Pivnichny, Regina Wang, Conrad Raab, Stella Vincent, Philip Davies, Malcolm Maccoss, Richard A Mumford, William K Hagmann
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  ABSTRACT: Extremely potent very late antigen-4 (VLA-4) antagonists with picomolar, whole blood activity and slow dissociation rates were discovered by incorporating an amino substituent on the proline fragment of the initial lead structure. This level of potency against the unactivated form of VLA-4 was shown to be sufficient to overcome the poor pharmacokinetic profiles typical of this class of VLA-4 antagonists, and sustained activity as measured by receptor occupancy was achieved in preclinical species after oral dosing.
  Journal of Medicinal Chemistry 06/2009; 52(11):3449-52. · 4.80 Impact Factor
• Article: Characterization of alpha(4)beta(1) (CD49d/CD29) on equine leukocytes: potential utility of a potent alpha(4)beta(1) (CD49d/CD29) receptor antagonist in the treatment of equine heaves (recurrent airway obstruction).

  Kelly M Treonze, Kenneth Alves, Paul Fischer, William K Hagmann, Donald Hora, Alison Kulick, Ken Vakerich, Nicholas D Smith, Russell B Lingham, Salony Maniar, [......], Jasmine Zunic, Benito Munoz, Peppi Prasit, Donald Nicholson, Qian Si, Keith Judd, Susan Nicolich, Patricia Kellerhouse, Donald Thompson, Richard A Mumford
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  ABSTRACT: The purpose of this study was to characterize the alpha(4)beta(1) receptor (CD49d/CD29, very late antigen-4, VLA-4) on circulating equine leukocytes and to evaluate the intrinsic potency of an alpha(4)beta(1) receptor antagonist (Compound B) in the horse. Ultimately, these studies would allow us to determine the suitability of treating recurrent airway obstruction (RAO; heaves) affected horses by blocking the cellular recruitment of lymphocytes and neutrophils into the lung. The data demonstrates the alpha(4)beta(1) integrin is present on horse lymphocytes and neutrophils (fluorescence-assisted cell sorter, FACS) and can bind low molecular weight alpha(4)beta(1) antagonists (Compounds A and B) with high affinity. K(D) values for the binding of Compound A to non-activated alpha(4)beta(1) on isolated horse PBMCs (peripheral blood mononuclear cells) and activated neutrophils were 17 pM and 27 pM, respectively. Compound B was identified as a suitable antagonist for performing a series of in vivo experiments. Compound B was found to possess excellent potency in horse whole blood, possessing IC(50) and IC(90) values of 39 pM and 172 pM, respectively. This represents a 3.9-fold molar excess of drug over the alpha(4)beta(1) concentration in blood. Following oral administration of Compound B (5 mg/kg) to beagle dogs and rhesus monkeys, rapid and sustained alpha(4)beta(1) receptor occupancy (>80%) was achieved and maintained for a period of 24 h. When Compound B was administered intravenously to the horse, by either a slow or rapid infusion at a dose of 0.3 mg/kg, receptor blockade of >80% was observed out to 24 h with a concomitant leukocytosis. We believe that Compound B possesses suitable intrinsic and pharmacological properties to be evaluated clinically in horses affected by RAO.
  Veterinary Immunology and Immunopathology 02/2009; 130(1-2):79-87. · 2.08 Impact Factor
• Article: Constraining the amide bond in N-sulfonylated dipeptide VLA-4 antagonists.

  Linda L Chang, Ginger X Yang, Ermengilda McCauley, Richard A Mumford, John A Schmidt, William K Hagmann
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  ABSTRACT: The integrin VLA-4 is implicated in several inflammatory disease states. In search of non-peptidic antagonists of VLA-4, rotational constraints were imposed on the amide bond of prototypical N-sulfonylated dipeptide VLA-4 antagonists. By judicious structural modification of the side chains, trisubstituted imidazoles with moderate binding potencies were obtained, for example, 19, VLA-4 IC(50)=237 nM.
  Bioorganic & medicinal chemistry letters 04/2008; 18(5):1688-91. · 2.65 Impact Factor
• Article: Influence of acid surrogates toward potency of VLA-4 antagonist.

  Shankar Venkatraman, Jongwon Lim, Merryl Cramer, Michael F Gardner, Joyce James, Kenneth Alves, Russell B Lingham, Richard A Mumford, Benito Munoz
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  ABSTRACT: A series of VLA-4 antagonist were synthesized wherein carboxylic acid was replaced by various acid surrogates. The effect of these acid surrogates toward potency was evaluated in a binding assay. A number of acid surrogates were potent antagonist of VLA-4, albeit significantly less potent than the corresponding carboxylic acid. Heterocyclic acid surrogate, oxadiazolidinone 3, demonstrated an improved pharmacokinetic property when dosed intravenously.
  Bioorganic & Medicinal Chemistry Letters 10/2005; 15(18):4053-6. · 2.55 Impact Factor
• Article: Bicyclic amidine inhibitors of nitric oxide synthase: discovery of perhydro-iminopyrindine and perhydro-iminoquinoline as potent, orally active inhibitors of inducible nitric oxide synthase.

  Ravindra N Guthikonda, Shrenik K Shah, Stephen G Pacholok, John L Humes, Richard A Mumford, Stephan K Grant, Renee M Chabin, Barbara G Green, Nancy Tsou, Richard Ball, Daniel S Fletcher, Silvi Luell, D Euan MacIntyre, Malcolm Maccoss
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  ABSTRACT: Syntheses and nitric oxide synthase inhibitory activity of cyclic amidines containing 5,6- 6,6- and 7,6-fused systems are described. X-ray structure determination facilitated the assignment of the stereochemistry of the most active compounds perhydro-2-iminoisoquinoline (8a) and perhydro-2-iminopyrindine (10a). Both 8a and 10a are very potent inhibitors of iNOS, with excellent selectivity over eNOS and they are orally active in rats with long duration suitable for once or twice a day dosing.
  Bioorganic & Medicinal Chemistry Letters 05/2005; 15(8):1997-2001. · 2.55 Impact Factor
• Article: Bioisosteric replacement of anilide with benzoxazole: potent and orally bioavailable antagonists of VLA-4.

  Linus S Lin, Thomas J Lanza, Laurie A Castonguay, Theodore Kamenecka, Ermenegilda McCauley, Gail Van Riper, Linda A Egger, Richard A Mumford, Xinchun Tong, Malcolm MacCoss, John A Schmidt, William K Hagmann
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  ABSTRACT: We have designed and synthesized a series of heterocyclic bioisosteres for an anilide based on molecular modeling. Excellent potency was retained in the benzoxazole and the benzimidazole derivatives, where a hydrogen bond acceptor is appropriately positioned to mimic the amide bond oxygen. The deletion of the hydrogen bond donor (N-H) led to improved lipophilicity and bioavailability. In the process, 9a was identified as a potent, specific, and bioavailable VLA-4 antagonist, while 9c was found to be a potent and bioavailable dual antagonist of VLA-4 and alpha(4)beta(7).
  Bioorganic & Medicinal Chemistry Letters 06/2004; 14(9):2331-4. · 2.55 Impact Factor
• Article: Amidines as amide bond replacements in VLA-4 antagonists.

  Theodore M Kamenecka, You-Jung Park, Linus S Lin, Stephen de Laszlo, Ermengilda D McCauley, Gail Van Riper, Linda Egger, Usha Kidambi, Richard A Mumford, Sharon Tong, Wei Tang, Adria Colletti, Yohannes Teffera, Ralph Stearns, Malcolm MacCoss, John A Schmidt, William K Hagmann
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  ABSTRACT: VLA-4 (alpha(4)beta(1), very late activating antigen-4), a key cell surface integrin plays an important role in inflammation by promoting leukocyte attachment and extravasation from the vasculature into the peripheral tissues. As such, VLA-4 antagonists may be useful in the treatment, prevention, and suppression of diseases where cell adhesion and migration are important such as asthma, rheumatoid arthritis, and multiple sclerosis. Herein, we report on the discovery, synthesis, and biological evaluation of amidines as small molecule antagonists of VLA-4.
  Bioorganic & Medicinal Chemistry Letters 06/2004; 14(9):2323-6. · 2.55 Impact Factor
• Article: A small molecule alpha4beta1/alpha4beta7 antagonist differentiates between the low-affinity states of alpha4beta1 and alpha4beta7: characterization of divalent cation dependence.

  Linda A Egger, Jin Cao, Christine McCallum, Usha Kidambi, Gail Van Riper, Ermengilda McCauley, Richard A Mumford, Thomas J Lanza, Linus S Lin, Stephen E de Laszlo, [......], Conrad E Raab, Mike A Wallace, Allen N Jones, William K Hagmann, John A Schmidt, R Blake Pepinsky, Daniel M Scott, Wen-Cherng Lee, Mark A Cornebise, Patricia A Detmers
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  ABSTRACT: An alpha4beta1/alpha4beta7 dual antagonist, 35S-compound 1, was used as a model ligand to study the effect of divalent cations on the activation state and ligand binding properties of alpha4 integrins. In the presence of 1 mM each Ca2+/Mg2+, 35S-compound 1 bound to several cell lines expressing both alpha4beta1 and alpha4beta7, but 2S-[(1-benzenesulfonyl-pyrrolidine-2S-carbonyl)-amino]-4-[4-methyl-2S-(methyl-[2-[4-(3-o-tolyl-ureido)-phenyl]-acetyl]-amino) pentanoylamino]-butyric acid (BIO7662), a specific alpha4beta1 antagonist, completely inhibited 35S-compound 1 binding, suggesting that alpha4beta1 was responsible for the observed binding. 35S-Compound 1 bound RPMI-8866 cells expressing predominantly alpha4beta7 with a KD of 1.9 nM in the presence of 1 mM Mn2+, and binding was inhibited only 29% by BIO7662, suggesting that the probe is a potent antagonist of activated alpha4beta7. With Ca2+/Mg2+, 35S-compound 1 bound Jurkat cells expressing primarily alpha4beta1 with a KD of 18 nM. In contrast, the binding of 35S-compound 1 to Mn2+-activated Jurkat cells occurred slowly, reaching equilibrium by 60 min, and failed to dissociate within another 60 min. The ability of four alpha4beta1/alpha4beta7 antagonists to block binding of activated alpha4beta1 or alpha4beta7 to vascular cell adhesion molecule-1 or mucosal addressin cell adhesion molecule-1, respectively, or to 35S-compound 1 was measured, and a similar rank order of potency was observed for native ligand and probe. Inhibition of 35S-compound 1 binding to alpha4beta1 in Ca2+/Mg2+ was used to identify nonselective antagonists among these four. These studies demonstrate that alpha4beta1 and alpha4beta7 have distinct binding properties for the same ligand, and binding parameters are dependent on the state of integrin activation in response to different divalent cations.
  Journal of Pharmacology and Experimental Therapeutics 10/2003; 306(3):903-13. · 3.83 Impact Factor
• Article: N-isonicotinoyl-(L)-4-aminophenylalanine derivatives as tight binding VLA-4 antagonists.

  George A Doherty, Ginger X Yang, Edite Borges, Sharon Tong, Ermengilda D McCauley, Kelly M Treonz, Gail Van Riper, Stephen Pacholok, Qian Si, Gloria C Koo, Kashmira Shah, Richard A Mumford, William K Hagmann
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  ABSTRACT: A series of isonicotinoyl-(L)-aminophenylalanine derivatives was prepared and evaluated as VLA-4 antagonists. These compounds exhibit subnanomolar binding affinity to VLA-4 and significant off-rates. The interplay between off-rate, protein binding and pharmacokinetics is discussed.
  Bioorganic & Medicinal Chemistry Letters 07/2003; 13(11):1891-5. · 2.55 Impact Factor
• Article: N-(3-phenylsulfonyl-3-piperidinoyl)-phenylalanine derivatives as potent, selective VLA-4 antagonists.

  Clare E Gutteridge, Stephen E de Laszlo, Theodore M Kamenecka, Ermengilda McCauley, Gail van Riper, Richard A Mumford, Usha Kidambi, Linda A Egger, Sharon Tong, William K Hagmann
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  ABSTRACT: The SAR of 1-sulfonyl-cyclopentyl carboxylic acid amides, ligands for the VLA-4 integrin, was investigated. This effort resulted in the identification of N-(3-phenylsulfonyl-3-piperidinoyl)-(L)-4-(2',6'-dimethoxyphenyl)phenylalanine 52 as a potent, selective VLA-4 antagonist (IC(50)=90 pM). Expansion of the SAR demonstrated that this structural unit can be used to identify a diverse series of sub-nanomolar antagonists.
  Bioorganic & Medicinal Chemistry Letters 04/2003; 13(5):885-90. · 2.55 Impact Factor
• Article: Substituted 3-amino biaryl propionic acids as potent VLA-4 antagonists.

  Ihor E Kopka, Linus S Lin, Richard A Mumford, Thomas Lanza, Plato A Magriotis, David Young, Stephen E DeLaszlo, Malcolm MacCoss, Sander G Mills, Gail Van Riper, [......], Linda A Egger, Usha Kidambi, Ralph Stearns, Adria Colletti, Yohannes Teffera, Sharon Tong, Karen Owens, Dorothy Levorse, John A Schmidt, William K Hagmann
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  ABSTRACT: A series of substituted N-(3,5-dichlorobenzenesulfonyl)-(L)-prolyl- and (L)-azetidyl-beta-biaryl beta-alanine derivatives was prepared as selective and potent VLA-4 antagonists. The 2,6-dioxygenated biaryl substitution pattern is important for optimizing potency. Oral bioavailability was variable and may be a result of binding to circulating plasma proteins.
  Bioorganic & Medicinal Chemistry Letters 10/2002; 12(17):2415-8. · 2.55 Impact Factor
• Article: N-aryl-prolyl-dipeptides as potent antagonists of VLA-4.

  Theodore M Kamenecka, Thomas Lanza, Stephen E de Laszlo, Bing Li, Ermengilda D McCauley, Gail Van Riper, Linda A Egger, Usha Kidambi, Richard A Mumford, Sharon Tong, Malcolm MacCoss, John A Schmidt, William K Hagmann
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  ABSTRACT: The design, synthesis, and biological evaluation of N-arylprolyl-dipeptide derivatives as small molecule VLA-4 antagonists is described. Potency against VLA-4 and alpha(4)beta(7) and rat pharmacokinetic evaluation revealed some advantages over the related N-(arylsulfonyl)-prolyl-dipeptide analogues.
  Bioorganic & Medicinal Chemistry Letters 09/2002; 12(16):2205-8. · 2.55 Impact Factor
• Article: N-(arylacetyl)-biphenylalanines as potent VLA-4 antagonists.

  Bing Li, Stephen E de Laszlo, Theodore M Kamenecka, Ihor E Kopka, Philippe L Durette, Thomas Lanza, Malcolm MacCoss, Sharon Tong, Richard A Mumford, Ermengilda D McCauley, Gail Van Riper, John A Schmidt, William K Hagmann
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  ABSTRACT: A series of potent N-(aralkyl-, arylcycloalkyl-, and heteroaryl-acyl)-4-biphenylalanine VLA-4 antagonists was prepared by rapid analogue methods using solid-phase chemistry. Further optimization led to several highly potent compounds (IC(50) <1 nM). Evaluation of rat pharmacokinetic revealed generally high clearance.
  Bioorganic & Medicinal Chemistry Letters 08/2002; 12(16):2141-4. · 2.55 Impact Factor
• Article: Alpha(4)beta(7)/alpha(4)beta(1) dual integrin antagonists block alpha(4)beta(7)-dependent adhesion under shear flow.

  Linda A Egger, Usha Kidambi, Jin Cao, Gail Van Riper, Ermengilda McCauley, Richard A Mumford, Suzanne Amo, Russell Lingham, Thomas Lanza, Linus S Lin, [......], David N Young, Ihor E Kopka, Sharon Tong, Bill Pikounis, Evelyn Benson, Sarah Warwood, Robert F Bargatze, William K Hagmann, John A Schmidt, Patricia A Detmers
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  ABSTRACT: The alpha(4) integrin, alpha(4)beta(7), plays an important role in recruiting circulating lymphocytes to the gastrointestinal tract, where its ligand mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is preferentially expressed on high endothelial venules (HEVs). Dual antagonists of alpha(4)beta(1) and alpha(4)beta(7), N-(2,6-dichlorobenzoyl)-(L)-4-(2',6'-bis-methoxyphenyl)phenylalanine (TR14035) and N-(N-[(3,5-dichlorobenzene)sulfonyl]-2-(R)-methylpropyl)-(D)-phenylalanine (compound 1), were tested for their ability to block the binding of alpha(4)beta(7)-expressing cells to soluble ligand in suspension and under in vitro and in vivo shear flow. Compound 1 and TR14035 blocked the binding of human alpha(4)beta(7) to an (125)I-MAdCAM-Ig fusion protein with IC(50) values of 2.93 and 0.75 nM, respectively. Both compounds inhibited binding of soluble ligands to alpha(4)beta(1) or alpha(4)beta(7) on cells of human or rodent origin with similar potency. Under shear flow in vitro, TR14035 and compound 1 blocked binding of human alpha(4)beta(7)-expressing RPMI-8866 cells or murine mesenteric lymph node lymphocytes to MAdCAM-Ig with IC(50) values of 0.1 and 1 microM, respectively. Intravital microscopy was used to quantitate alpha(4)-dependent adhesion of fluorescent murine lymphocytes in Peyer's patch HEVs. When cells were prestimulated with 2 mM Mn(2+) to activate alpha(4)beta(7) binding to ligand, anti-alpha(4) monoclonal antibody (mAb) [10 mg/kg (mpk) i.v.] blocked adhesion by 95%, and anti-beta(1) mAb did not block adhesion, demonstrating that this interaction was dependent on alpha(4)beta(7). TR14035 blocked adhesion to HEVs [ED(50) of 0.01-0.1 mpk i.v.], and compound 1 blocked adhesion by 47% at 10 mpk i.v. Thus, alpha(4)beta(7)/alpha(4)beta(1) antagonists blocked alpha(4)beta(7)-dependent adhesion of lymphocytes to HEVs under both in vitro and in vivo shear flow.
  Journal of Pharmacology and Experimental Therapeutics 08/2002; 302(1):153-62. · 3.83 Impact Factor
• Article: Comparative assessment of the ligand and metal ion binding properties of integrins alpha9beta1 and alpha4beta1.

  R Blake Pepinsky, Richard A Mumford, Ling Ling Chen, Diane Leone, Suzanne E Amo, Gail Van Riper, Adrian Whitty, Brian Dolinski, Roy R Lobb, Dennis C Dean, Linda L Chang, Conrad E Raab, Qian Si, William K Hagmann, Russell B Lingham
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  ABSTRACT: Integrins alpha9beta1 and alpha4beta1 form a distinct structural class, but while alpha4beta1 has been subjected to extensive study, alpha9beta1 remains poorly characterized. We have used the small molecule N-(benzenesulfonyl)-(L)-prolyl-(L)-O-(1-pyrrolidinylcarbonyl)tyrosine (3) to investigate the biochemical properties of alpha9beta1 and directly compare these properties with those of alpha4beta1. Compound 3 has a high affinity for both integrins with K(D) values of < or =3 and 180 pM for alpha9beta1 in 1 mM Mn2+ (activating) and 1 mM Ca2+ and 1 mM Mg2+ (nonactivating) conditions and < or =5 and 730 pM for alpha4beta1 under the corresponding conditions. Ca2+ treatment promoted the binding of 3 to both integrins (EC50 = 30 microM Ca2+ in both cases). Compound 3 binding to both integrins was also stimulated by the addition of the activating monoclonal antibody TS2/16. These findings indicate that the mechanisms by which metal ions and TS2/16 regulate ligand binding to alpha9beta1 and alpha4beta1 are similar. The binding of 3 to both integrins induced the mAb 9EG7 LIBS epitope, a property consistent with occupancy of the receptor's ligand binding site by 3. But whereas EGTA treatment inhibited the binding of 9EG7 to alpha4beta1, it stimulated the binding of 9EG7 to alpha9beta1. The 9EG7 and TS2/16 effects point to contributions of the beta1-chains on binding. Cross-linking data revealed that the integrin alpha-chains are also involved in binding the small molecule, as stable linkages were observed on both the alpha9 chain of alpha9beta1 and the alpha4 chain of alpha4beta1. Extensive structure-activity analyses with natural and synthetic ligands indicate distinct features of the ligand binding pockets. Most notable was the estimated >1000-fold difference in the affinity of the integrins for VCAM-1, which binds alpha4beta1with an apparent K(D) of 10 nM and alpha9beta1 with an apparent K(D) of >10 microM. Differences were also seen in the binding of alpha9beta1 and alpha4beta1 to osteopontin. Compound 3 competed effectively for the binding of VCAM-1 and osteopontin to both integrins. While these studies show many similarities in the biochemical properties of alpha9beta1 and alpha4beta1, they identify important differences in their structure and function that can be exploited in the design of selective alpha9beta1 and alpha4beta1 inhibitors.
  Biochemistry 07/2002; 41(22):7125-41. · 3.42 Impact Factor
• Article: N-Tetrahydrofuroyl-(L)-phenylalanine derivatives as potent VLA-4 antagonists.

  Ginger X Yang, Linda L Chang, Quang Truong, George A Doherty, Plato A Magriotis, Stephen E de Laszlo, Bing Li, Malcolm MacCoss, Usha Kidambi, Linda A Egger, Ermengilda McCauley, Gail Van Riper, Richard A Mumford, John A Schmidt, William K Hagmann
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  ABSTRACT: Given the proposed involvement of VLA-4 in inflammatory processes, a program to identify orally active VLA-4 antagonists was initiated. Herein, we report the discovery of a N-tetrahydrofuroyl-(L)-phenylalanine derivative (17) and related analogues as potent VLA-4 antagonists with good oral bioavailability.
  Bioorganic & Medicinal Chemistry Letters 07/2002; 12(11):1497-500. · 2.55 Impact Factor