Publications by authors named "Katherine Figueroa"

18 Publications

  • Page 1 of 1

Precision Tracing of Household Dengue Spread Using Inter- and Intra-Host Viral Variation Data, Kamphaeng Phet, Thailand.

Emerg Infect Dis 2021 06;27(6):1637-1644

Dengue control approaches are best informed by granular spatial epidemiology of these viruses, yet reconstruction of inter- and intra-household transmissions is limited when analyzing case count, serologic, or genomic consensus sequence data. To determine viral spread on a finer spatial scale, we extended phylogenomic discrete trait analyses to reconstructions of house-to-house transmissions within a prospective cluster study in Kamphaeng Phet, Thailand. For additional resolution and transmission confirmation, we mapped dengue intra-host single nucleotide variants on the taxa of these time-scaled phylogenies. This approach confirmed 19 household transmissions and revealed that dengue disperses an average of 70 m per day between households in these communities. We describe an evolutionary biology framework for the resolution of dengue transmissions that cannot be differentiated based on epidemiologic and consensus genome data alone. This framework can be used as a public health tool to inform control approaches and enable precise tracing of dengue transmissions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3201/eid2706.204323DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8153871PMC
June 2021

Disruption of the cholinergic anti-inflammatory response by R5-tropic HIV-1 protein gp120.

J Biol Chem 2021 Jan-Jun;296:100618. Epub 2021 Mar 31.

Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico, USA; Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico, USA; Institute of Neurobiology, University of Puerto Rico Medical Science Campus, San Juan, Puerto Rico, USA; Molecular Sciences Research Center, University of Puerto Rico, San Juan, Puerto Rico, USA. Electronic address:

Despite current pharmacological intervention strategies, patients with HIV still suffer from chronic inflammation. The nicotinic acetylcholine receptors (nAChRs) are widely distributed throughout the nervous and immune systems. In macrophages, activation of alpha7-nAChR (α7-nAChR) controls inflammatory processes through the cholinergic anti-inflammatory response (CAR). Given that this innate immune response controls inflammation and α7-nAChR plays a critical role in the regulation of systemic inflammation, we investigated the effects of an R5-tropic HIV soluble component, gp120, on the CAR functioning. We previously demonstrated that X4-tropic HIV-1 gp120 disrupts the CAR as well as inducing upregulation of the α7-nAChR in vitro in monocyte-derived macrophages (MDMs), which correlates with the upregulation observed in monocytes, T-lymphocytes, and MDMs recovered from HIV-infected people. We demonstrate here using imaging and molecular assays that the R5-tropic HIV-1 glycoprotein gp120 upregulates the α7-nAChR in MDMs dependent on CD4 and/or CCR5 activation. This upregulation was also dependent on MEK1 since its inhibition attenuates the upregulation of α7-nAChR induced by gp120 and was concomitant with an increase in basal calcium levels, which did not result in apoptosis. Moreover, the CAR was determined to be disrupted, since α7-nAChR activation in MDMs did not reduce the production of the proinflammatory cytokines IL-6, GRO-α, or I-309. Furthermore, a partial antagonist of α7-nAChR, bupropion, rescued IL-6 but not GRO-α or I-309 production. Together, these results demonstrate that gp120 disrupts the CAR in MDMs. Other medications targeting the α7-nAChR need to be tested to reactivate the CAR to ameliorate inflammation in HIV-infected subjects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jbc.2021.100618DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8102909PMC
March 2021

DNA spike-ins enable confident interpretation of SARS-CoV-2 genomic data from amplicon-based sequencing.

bioRxiv 2021 Mar 16. Epub 2021 Mar 16.

The rapid global spread and continued evolution of SARS-CoV-2 has highlighted an unprecedented need for viral genomic surveillance and clinical viral sequencing. Amplicon-based sequencing methods provide a sensitive, low-cost and rapid approach but suffer a high potential for contamination, which can undermine lab processes and results. This challenge will only increase with expanding global production of sequences by diverse research groups for epidemiological and clinical interpretation. We present an approach which uses synthetic DNA spike-ins (SDSIs) to track samples and detect inter-sample contamination through a sequencing workflow. Applying this approach to the ARTIC Consortium's amplicon design, we define a series of best practices for Illumina-based sequencing and provide a detailed characterization of approaches to increase sensitivity for low-viral load samples incorporating the SDSIs. We demonstrate the utility and efficiency of the SDSI method amidst a real-time investigation of a suspected hospital cluster of SARS-CoV-2 cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1101/2021.03.16.435654DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7987014PMC
March 2021

The evolution of dengue-2 viruses in Malindi, Kenya and greater East Africa: Epidemiological and immunological implications.

Infect Genet Evol 2021 Jun 6;90:104617. Epub 2020 Nov 6.

Basic Science Laboratory, US Army Medical Research Directorate - Africa (USAMRD-A), Kisumu, Kenya.

Kenya experiences a substantial burden of dengue, yet there are very few DENV-2 sequence data available from this country and indeed the entire continent of Africa. We therefore undertook whole genome sequencing and evolutionary analysis of fourteen dengue virus (DENV)-2 strains sampled from Malindi sub-County Hospital during the 2017 DENV-2 outbreak in the Kenyan coast. We further performed an extended East African phylogenetic analysis, which leveraged 26 complete African env genes. Maximum likelihood analysis showed that the 2017 outbreak was due to the Cosmopolitan genotype, indicating that this has been the only confirmed human DENV-2 genotype circulating in Africa to date. Phylogeographic analyses indicated transmission of DENV-2 viruses between East Africa and South/South-West Asia. Time-scaled genealogies show that DENV-2 viruses shows spatial structure at the country level in Kenya, with a time-to-most-common-recent ancestor analysis indicating that these DENV-2 strains were circulating for up to 5.38 years in Kenya before detection in the 2017 Malindi outbreak. Selection pressure analyses indicated sampled Kenyan DENV strains uniquely being under positive selection at 6 sites, predominantly across the non-structural genes, and epitope prediction analyses showed that one of these sites corresponds to a putative predicted MHC-I CD8+ DENV-2 Cosmopolitan virus epitope only evident in a sampled Kenyan virus. Taken together, our findings indicate that the 2017 Malindi DENV-2 outbreak arose from a strain which had circulated for several years in Kenya before recent detection, has experienced diversifying selection pressure, and may contain new putative immunogens relevant to vaccine design. These findings prompt further genomic epidemiology studies in this and other Kenyan locations to further elucidate the transmission dynamics of DENV in this region.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.meegid.2020.104617DOI Listing
June 2021

The origins of dengue and chikungunya viruses in Ecuador following increased migration from Venezuela and Colombia.

BMC Evol Biol 2020 02 19;20(1):31. Epub 2020 Feb 19.

Viral Diseases Branch, Walter Reed Army institute of Research, Silver Spring, MD, USA.

Background: In recent years, Ecuador and other South American countries have experienced an increase in arboviral diseases. A rise in dengue infections was followed by introductions of chikungunya and Zika, two viruses never before seen in many of these areas. Furthermore, the latest socioeconomic and political instability in Venezuela and the mass migration of its population into the neighboring countries has given rise to concerns of infectious disease spillover and escalation of arboviral spread in the region.

Results: We performed phylogeographic analyses of dengue (DENV) and chikungunya (CHIKV) virus genomes sampled from a surveillance site in Ecuador in 2014-2015, along with genomes from the surrounding countries. Our results revealed at least two introductions of DENV, in 2011 and late 2013, that initially originated from Venezuela and/or Colombia. The introductions were subsequent to increases in the influx of Venezuelan and Colombian citizens into Ecuador, which in 2013 were 343% and 214% higher than in 2009, respectively. However, we show that Venezuela has historically been an important source of DENV dispersal in this region, even before the massive exodus of its population, suggesting already established paths of viral distribution. Like DENV, CHIKV was introduced into Ecuador at multiple time points in 2013-2014, but unlike DENV, these introductions were associated with the Caribbean. Our findings indicated no direct CHIKV connection between Ecuador, Colombia, and Venezuela as of 2015, suggesting that CHIKV was, at this point, not following the paths of DENV spread.

Conclusion: Our results reveal that Ecuador is vulnerable to arbovirus import from many geographic locations, emphasizing the need of continued surveillance and more diversified prevention strategies. Importantly, increase in human movement along established paths of viral dissemination, combined with regional outbreaks and epidemics, may facilitate viral spread and lead to novel virus introductions. Thus, strengthening infectious disease surveillance and control along migration routes and improving access to healthcare for the vulnerable populations is of utmost importance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12862-020-1596-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7031975PMC
February 2020

Global Outbreaks and Origins of a Chikungunya Virus Variant Carrying Mutations Which May Increase Fitness for : Revelations from the 2016 Mandera, Kenya Outbreak.

Am J Trop Med Hyg 2019 05;100(5):1249-1257

United States Army Medical Research Directorate - Kenya, Nairobi, Kenya.

In 2016, a chikungunya virus (CHIKV) outbreak was reported in Mandera, Kenya. This was the first major CHIKV outbreak in the country since the global reemergence of this virus in Kenya in 2004. We collected samples and sequenced viral genomes from this outbreak. All Kenyan genomes contained two mutations, E1:K211E and E2:V264A, recently reported to have an association with increased infectivity, dissemination, and transmission in the vector. Phylogeographic inference of temporal and spatial virus relationships showed that this variant emerged within the East, Central, and South African lineage between 2005 and 2008, most probably in India. It was also in India where the first large outbreak caused by this virus appeared, in New Delhi, 2010. More importantly, our results also showed that this variant is no longer contained to India. We found it present in several major outbreaks, including the 2016 outbreaks in Pakistan and Kenya, and the 2017 outbreak in Bangladesh. Thus, this variant may have a capability of driving large CHIKV outbreaks in different regions of the world. Our results point to the importance of continued genomic-based surveillance and prompt urgent vector competence studies to assess the level of vector susceptibility and virus transmission, and the impact this might have on this variant's epidemic potential and global spread.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4269/ajtmh.18-0980DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6493958PMC
May 2019

Metagenomic Analysis Reveals Three Novel and Prevalent Mosquito Viruses from a Single Pool of Collected in the Republic of Korea.

Viruses 2019 03 5;11(3). Epub 2019 Mar 5.

Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.

Arboviruses continue to be a significant global health concern. The unbiased metagenomic analyses of mosquito-borne and mosquito-specific viruses are useful to understand viral diversity and for the surveillance of pathogens of medical and veterinary importance. Metagenomic analysis was conducted on 6368 mosquitoes (736 pools), covering 16 species from 18 locations throughout the Republic of Korea (ROK) in 2016. In this report, we describe three viruses detected in a single pool of collected at Yongsan U.S. Army Garrison, located in a densely populated district of Seoul, the ROK. The three novel viruses, designated as Yongsan bunyavirus 1 (YBV1), Yongsan picorna-like virus 3 (YPLV3) and Yongsan sobemo-like virus 1 (YSLV1), share sequence and structural characteristics with members belonging to the family , order , and family , with shared RNA-dependent RNA polymerase (RdRp) amino acid identities of 40%, 42% and 86%, respectively. The real-time reverse transcription and polymerase chain reaction (RT-PCR) of 3493 (257 pools) showed a high prevalence of YBV1 and YSLV1 viruses, which were present in 65% and 62% of tested pools, respectively. This study highlighted the utility of a metagenomic sequencing approach for arbovirus discovery and for a better understanding of the virome of potential medically relevant vectors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/v11030222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6466275PMC
March 2019

JNJ-26070109 [(R)4-bromo-N-[1-(2,4-difluoro-phenyl)-ethyl]-2-(quinoxaline-5-sulfonylamino)-benzamide]: a novel, potent, and selective cholecystokinin 2 receptor antagonist with good oral bioavailability.

J Pharmacol Exp Ther 2011 Jul 14;338(1):328-36. Epub 2011 Apr 14.

Johnson & Johnson Pharmaceutical Research & Development, LLC San Diego, California 92101, USA.

JNJ-26070109 [(R)4-bromo-N-[1-(2,4-difluoro-phenyl)-ethyl]-2-(quinoxaline-5-sulfonylamino)-benzamide] is a representative of a new chemical class of competitive antagonists of cholecystokinin 2 (CCK2) receptors. In this study, the primary in vitro pharmacology of JNJ-26070109 was evaluated along with the pharmacokinetic and pharmacodynamic properties of this compound in rat and canine models of gastric acid secretion. JNJ-26070109 expressed high affinity for human (pK(I) = 8.49 ± 0.13), rat (pK(I) = 7.99 ± 0.08), and dog (pK(I) = 7.70 ± 0.14) CCK2 receptors. The selectivity of JNJ-26070109 at the CCK2 receptor versus the CCK1 receptor was species-dependent, with the greatest degree of selectivity (>1200-fold) measured at the human isoforms of the CCK1 receptor (selectivity at CCK2 versus CCK1 receptors: human, ∼1222-fold; rat, ∼324-fold; dog ∼336-fold). JNJ-26070109 behaved as a surmountable, competitive, antagonist of human CCK2 receptors in a calcium mobilization assay (pK(B) = 8.53 ± 0.05) and in pentagastrin-stimulated gastric acid secretion in the isolated, lumen-perfused, mouse stomach assay (pK(B) = 8.19 ± 0.13). The pharmacokinetic profile of this compound was determined in vivo in rats and dogs. JNJ-26070109 was shown to have high oral bioavailability (%F rat = 73 ± 16; %F dog = 92 ± 12) with half lives of 1.8 ± 0.3 and 1.2 ± 0.1 h in rat and dog, respectively. The pharmacodynamic properties of this compound were investigated using two in vivo models. In conscious rat and dog chronic gastric fistula models of pentagastrin-stimulated acid secretion, JNJ-26070109 had oral EC(50) values of 1.5 and 0.26 μM, respectively. Overall, we have demonstrated that JNJ-26070109 is a high-affinity, selective CCK2 receptor antagonist with good pharmacokinetic properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1124/jpet.110.178483DOI Listing
July 2011

One hundred years of histamine research.

Adv Exp Med Biol 2010 ;709:1-9

Johnson & Johnson Pharmaceutical Research and Development L.L.C., Merryfield Row, San Diego, California, USA.

In this introductory chapter, we revisit some of the landmarks in the history of histamine research. Since histamine was first synthesized (1907) and isolated as a bacterial contaminant of an extract of ergot (1910), the elucidation of its role in health and disease and its molecular mechanism of action have been continuous, reflecting the application of advances in scientific knowledge, technology and therapeutics over the last 100 years. It appears that the research will continue indefinitely as the nature of the problem is inherently fractal. First, there was a single chemical entity, described in terms of state-of-the-art, two-dimensional projections of structures introduced by Fischer in 1891, and an idea that such potent chemicals produced their effects on biological systems as a consequence of an exquisite interaction with a receptive substance, the revolutionary concept of Langley (1905). Today, we recognize four receptor subtypes with multiple activation states and multiple coupling to intracellular effector systems, so that we are no longer able to reliably and in all instances classify compounds interacting with the histamine receptors simply as agonists or antagonists. The complexity is potentially overwhelming, but the promise of value to patients beyond that already provided by the first approved generations of histamine receptor blockers is a compelling driver.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/978-1-4419-8056-4_1DOI Listing
July 2011

5-Hydroxytryptamine receptor assays.

Curr Protoc Pharmacol 2009 Sep;Chapter 4:Unit4.19

Johnson & Johnson PRD, La Jolla, California, USA.

5-Hydroxytryptamine (5-HT) receptors, by virtue of their broad expression pattern in peripheral and central tissues, regulate diverse physiological and behavioral responses through the activation of fourteen molecularly distinct receptor subtypes. The tissue-specific distribution of these receptors confers specificity for the actions of serotonin and highlights the therapeutic potential of serotonin receptor modulators. To better assess this therapeutic potential, it is useful to characterize serotonergic agonists and antagonists in physiologically relevant organ systems. Provided in this unit are twelve tissue bath assays using vascular and smooth muscle tissues isolated from guinea-pig, rat, and rabbit. These tests make possible the analyses of compounds at nine serotonin receptor subtypes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/0471141755.ph0419s46DOI Listing
September 2009

Profiling of dynamically changed gene expression in dorsal root ganglia post peripheral nerve injury and a critical role of injury-induced glial fibrillary acidic protein in maintenance of pain behaviors [corrected].

Pain 2009 May;143(1-2):114-22

Department of Anesthesiology & Perioperative Care, School of Medicine, University of California Irvine, Irvine, CA 92697, USA.

To explore cellular changes in sensory neurons after nerve injury and to identify potential target genes contributing to different stages of neuropathic pain development, we used Affymetrix oligo arrays to profile gene expression patterns in L5/6 dorsal root ganglia (DRG) from the neuropathic pain model of left L5/6 spinal nerve ligation at different stages of neuropathic pain development. Our data indicated that nerve injury induced changes in expression of genes with similar biological functions in a temporal specific manner that correlates with particular stages of neuropathic pain development, indicating dynamic neuroplasticity in the DRG in response to peripheral nerve injury and during neuropathic pain development. Data from post-array validation indicated that there was a temporal correlation between injury-induced expression of the glial fibrillary acidic protein (GFAP), a marker for activated astrocytes, and neuropathic pain development. Spinal nerve ligation injury in GFAP knockout mice resulted in neuropathic pain states with similar onset, but a shortened duration compared with that in age, and gender-matched wild-type littermates. Intrathecal GFAP antisense oligonucleotide treatment in injured rats with neuropathic pain states reversed injury-induced behavioral hypersensitivity and GFAP upregulation in DRG and spinal cord. Together, these findings indicate that injury-induced GFAP upregulation not only serves as a marker for astrocyte activation, but it may also play a critical, but yet identified, role in the maintenance of neuropathic pain states.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.pain.2009.02.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2743568PMC
May 2009

Selectivity of agonists for the active state of M1 to M4 muscarinic receptor subtypes.

J Pharmacol Exp Ther 2009 Jan 29;328(1):331-42. Epub 2008 Sep 29.

Department of Pharmacology, University of California, Irvine, California 92697-4625, USA.

We measured the intrinsic relative activity (RA(i)) of muscarinic agonists to detect possible selectivity for receptor subtypes and signaling pathways. RA(i) is a relative measure of the microscopic affinity constant of an agonist for the active state of a GPCR expressed relative to that of a standard agonist. First, we estimated RA(i) values for a panel of agonists acting at the M(4) muscarinic receptor coupled to three distinct G-protein pathways: G(i) inhibition of cAMP accumulation, G(s) stimulation of cAMP accumulation, and G alpha(15) stimulation of phosphoinositide hydrolysis. Our results show similar RA(i) values for each agonist, suggesting that the same active state of the M(4) receptor triggers the activation of the three G proteins. We also estimated RA(i) values for agonists across M(1) to M(4) muscarinic subtypes stably transfected in Chinese hamster ovary cells. Our results show selectivity of McN-A-343 [4-I-[3-chlorophenyl]carbamoyloxy)-2-butynyltrimethylammnonium chloride] for the M(1) and M(4) subtypes and selectivity of pilocarpine for the M(1) and M(3) subtypes. The other agonists tested lacked marked selectivity among M(1) to M(4) receptors. Finally, we estimated RA(i) values from published literature on M(1), M(2), and M(3) muscarinic responses and obtained results consistent with our own studies. Our results show that the RA(i) estimate is a useful receptor-dependent measure of agonist activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1124/jpet.108.145219DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2644050PMC
January 2009

Use of acetylcholine mustard to study allosteric interactions at the M(2) muscarinic receptor.

J Pharmacol Exp Ther 2008 Nov 5;327(2):518-28. Epub 2008 Aug 5.

Department of Pharmacology, School of Medicine, University of California, Irvine, Irvine, CA 92697-4625, USA.

We explored the interaction of a nitrogen mustard derivative of acetylcholine with the human M(2) muscarinic receptor expressed in Chinese hamster ovary cells using the muscarinic radioligand, [3H]N-methylscopolamine (NMS). Acetylcholine mustard caused a concentration-dependent, first-order loss of [3H]NMS binding at 37 degrees C, with the half-maximal rate constant occurring at 24 microM and a maximal rate constant of 0.16 min(-1). We examined the effects of various ligands on the rate of alkylation of M(2) receptors by acetylcholine mustard. N-methylscopolamine and 4-(trimethylamino)-2-butynyl-(3-chlorophenyl)carbamate (McN-A-343) competitively slowed the rate of alkylation, whereas the inhibition by gallamine reached a plateau at high concentrations, indicating allosteric inhibition. In contrast, 17-beta-hydroxy-17-alpha-ethynyl-5-alpha-androstano[3,2-beta]-pyrimido[1,2-alpha]benzimidazole (WIN 51708) had no effect. We also measured the inhibition of [3H]NMS binding by acetylcholine mustard at 0 degrees C, conditions under which there is little or no detectable covalent binding. In these experiments, the dissociation constant of the aziridinium ion of acetylcholine mustard was estimated to be 12.3 microM. In contrast, the parent mustard and alcoholic hydrolysis product of acetylcholine mustard were without effect. Our results show that measurement of the effects of ligands on the rate of inactivation of the orthosteric site by a small site-directed electrophile is a powerful method for discriminating competitive inhibition from allosterism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1124/jpet.108.141234DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2677819PMC
November 2008

Injury discharges regulate calcium channel alpha-2-delta-1 subunit upregulation in the dorsal horn that contributes to initiation of neuropathic pain.

Pain 2008 Oct 20;139(2):358-366. Epub 2008 Jun 20.

Department of Pharmacology, University of California Irvine, Irvine, CA 92697, USA Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555, USA Department of Anesthesiology, University of California Irvine, Irvine, CA 92697, USA.

Previous studies have shown that peripheral nerve injury in rats induces increased expression of the voltage gated calcium channel (VGCC) alpha-2-delta-1 subunit (Ca v alpha2 delta1) in spinal dorsal horn and sensory neurons in dorsal root ganglia (DRG) that correlates to established neuropathic pain states. To determine if injury discharges trigger Ca v alpha2 delta1 induction that contributes to neuropathic pain initiation, we examined allodynia onset and Ca v alpha2 delta1 levels in DRG and spinal dorsal horn of spinal nerve ligated rats after blocking injury induced neural activity with a local brief application of lidocaine on spinal nerves before the ligation. The lidocaine pretreatment blocked ligation-induced discharges in a dose-dependent manner. Similar pretreatment with the effective concentration of lidocaine diminished injury-induced increases of the Ca v alpha2 delta1 in DRG and abolished that in spinal dorsal horn specifically, and resulted in a delayed onset of tactile allodynia post-injury. Both dorsal horn Ca v alpha2 delta1 upregulation and tactile allodynia in the lidocaine pretreated rats returned to levels similar to that in saline pretreated controls 2 weeks post the ligation injury. In addition, preemptive intrathecal Ca v alpha2 delta1 antisense treatments blocked concurrently injury-induced allodynia onset and Ca v alpha2 delta1 upregulation in dorsal spinal cord. These findings indicate that injury induced discharges regulate Ca v alpha2 delta1 expression in the spinal dorsal horn that is critical for neuropathic allodynia initiation. Thus, preemptive blockade of injury-induced neural activity or Ca v alpha2 delta1 upregulation may be a beneficial option in neuropathic pain management.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.pain.2008.05.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2613852PMC
October 2008

3-[5-(3,4-Dichloro-phenyl)-1-(4-methoxy-phenyl)-1H-pyrazol-3-yl]-2-m-tolyl-propionate (JNJ-17156516), a novel, potent, and selective cholecystokinin 1 receptor antagonist: in vitro and in vivo pharmacological comparison with dexloxiglumide.

J Pharmacol Exp Ther 2007 Nov 7;323(2):562-9. Epub 2007 Aug 7.

Johnson & Johnson Pharmaceutical Research & Development L.L.C., San Diego, California 92121, USA.

3-[5-(3,4-Dichloro-phenyl)-1-(4-methoxy-phenyl)-1H-pyrazol-3-yl]-2-m-tolyl-propionate (JNJ-17156516) is a novel, potent, and selective cholecystokinin (CCK)1-receptor antagonist. In this study, the pharmacology of JNJ-17156516 was investigated both in vitro and in vivo, and the pharmacokinetic profile was evaluated in rats. JNJ-17156516 expressed high-affinity at the cloned human (pK(I) = 7.96 +/- 0.11), rat (pK(I) = 8.02 +/- 0.11), and canine (pK(I) = 7.98 +/- 0.04) CCK1 receptors, and it was also highly selective for the CCK1 receptor compared with the CCK2 receptor across the same species ( approximately 160-, approximately 230-, and approximately 75-fold, respectively). The high affinity of JNJ-17156516 at CCK1 receptors in vitro was confirmed in radioligand binding studies on fresh human gallbladder tissue (pK(I) = 8.22 +/- 0.05). In a functional in vitro assay of guinea pig gallbladder contraction, JNJ-17156516 behaved as a competitive antagonist, with a pK(B) value of 8.00 +/- 0.07. In vivo, JNJ-17156516 produced a parallel, rightward shift in the CCK-8S-evoked contraction of the guinea pig gallbladder. The dose required to shift the CCK-8S dose-response curve was 240 nmol kg(-1) i.v. In the anesthetized rat, JNJ-17156516 produced a dose-related decrease in the number of duodenal contractions evoked by infusion of CCK-8S, with an ED(50) = 484 nmol kg(-1). Pharmacokinetic analysis of JNJ-17156516 in rats, revealed that JNJ-17156516 had a half-life of 3.0 +/- 0.5 h and a very high bioavailability (108 +/- 10%) in this species. Overall, we have demonstrated that JNJ-17156516 is a high-affinity selective human CCK1 receptor antagonist with good pharmacokinetic properties in rats.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1124/jpet.107.124578DOI Listing
November 2007

Estimation of agonist activity at G protein-coupled receptors: analysis of M2 muscarinic receptor signaling through Gi/o,Gs, and G15.

J Pharmacol Exp Ther 2007 Jun 28;321(3):1193-207. Epub 2007 Mar 28.

Department of Physical Sciences, Chapman University, Orange, California, USA.

We developed novel methods for analyzing the concentration-response curve of an agonist to estimate the product of observed affinity and intrinsic efficacy, expressed relative to that of a standard agonist. This parameter, termed intrinsic relative activity (RA(i)), is most applicable for the analysis of responses at G protein-coupled receptors. RA(i) is equivalent to the potency ratios that agonists would exhibit in a hypothetical, highly sensitive assay in which all agonists behave as full agonists, even those with little intrinsic efficacy. We investigated muscarinic responses at the M(2) receptor, including stimulation of phosphoinositide hydrolysis through G(alpha15) in HEK 293T cells, inhibition of cAMP accumulation through G(i) in Chinese hamster ovary (CHO) cells, and stimulation of cAMP accumulation through G(s) in CHO cells treated with pertussis toxin. The RA(i) values of carbachol, oxotremorine-M, and the enantiomers of aceclidine were approximately the same in the three assay systems. In contrast, the activity of 4-[[N-[3-chlorophenyl]carbamoy]oxy-2-butynyl]trimethylammonium chloride (McN-A-343) was approximately 10-fold greater at M(2) receptors coupled to G(alpha15) in HEK 293T cells compared with M(2) receptors coupled to G(i) in the same cells or in CHO cells. Our results show that the RA(i) estimate is a useful measure for quantifying agonist activity across different assay systems and for detecting agonist directed signaling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1124/jpet.107.120857DOI Listing
June 2007

Species-dependent smooth muscle contraction to Neuromedin U and determination of the receptor subtypes mediating contraction using NMU1 receptor knockout mice.

Br J Pharmacol 2006 Apr;147(8):886-96

Johnson & Johnson Pharmaceutical Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA 92121, USA.

The peptide ligand neuromedin U (NMU) has been implicated in an array of biological activities, including contraction of uterine, intestinal and urinary bladder smooth muscle. However, many of these responses appear to be species-specific. This study was undertaken to fully elucidate the range of smooth muscle-stimulating effects of NMU in rats, mice and guinea-pigs, and to examine the extent of the species differences. In addition, the NMU1 receptor knockout mouse was used to determine which receptor subtype mediates the contractile responses generated by NMU in the mouse. A range of isolated organ in vitro bioassays were carried out, which were chosen to re-confirm previous literature reports (uterine and stomach fundus contraction) and also to explore potentially novel smooth muscle responses to NMU. This investigation uncovered a number of previously unidentified NMU-mediated responses: contraction of rat lower esophageal sphinster (LES), rat ileum, mouse gallbladder, enhancement of electrically evoked contractions in rat and mouse vas deferens, and a considerable degree of cross-species differences. Studies using the NMU1 receptor knockout mice revealed that in the mouse fundus and gallbladder assays the NMU contractile response was mediated entirely through the NMU1 receptor subtype, whereas, in assays of mouse uterus and vas deferens, the response to NMU was unchanged in the NMU1 receptor knockout mouse, suggesting that the NMU response may be mediated through the NMU2 receptor subtype. NMU receptor subtype-selective antagonists are required to further elucidate the role of the individual receptor subtypes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/sj.bjp.0706677DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1760708PMC
April 2006

Prevention of bone loss in renal transplant recipients: a prospective, randomized trial of intravenous pamidronate.

J Am Soc Nephrol 2003 Oct;14(10):2669-76

Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10467, USA.

Renal transplant recipients are at risk of developing bone abnormalities that result in bone loss and bone fractures. These are related to underlying renal osteodystrophy, hypophosphatemia, and immunosuppressive treatment regimen. Although bisphosphonates are useful in ameliorating bone mineral loss after transplantation, it is not known whether their use in renal transplant patients leads to excessive suppression of bone turnover and increased incidence of adynamic bone disease. A randomized, prospective, controlled, clinical trial was conducted using the bisphosphonate pamidronate intravenously in patients with new renal transplants. Treatment subjects (PAM) received pamidronate with vitamin D and calcium at baseline and at months 1, 2, 3, and 6. Control (CON) subjects received vitamin D and calcium only. During months 6 to 12, the subjects were observed without pamidronate treatment. Biochemical parameters of bone turnover were obtained monthly and, bone mineral density (BMD) was obtained at baseline and months 6 and 12. Bone biopsies for mineralized bone histology were obtained at baseline and at 6 mo in a subgroup of subjects who underwent scheduled living donor transplantation. PAM preserved bone mass at 6 and 12 mo as measured by bone densitometry and histomorphometry. CON had decreased vertebral BMD at 6 and 12 mo (4.8 +/- 0.08 and 6.1 +/- 0.09%, respectively). Biochemical parameters of bone turnover were similar in both groups at 6 and 12 mo. Bone histology revealed low turnover bone disease in 50% of the patients at baseline. At 6 mo, all of PAM had adynamic bone disease, whereas 50% of CON continued to have or developed decreased bone turnover. Pamidronate preserved vertebral BMD during treatment and 6 mo after cessation of treatment. Pamidronate treatment was associated with development of adynamic bone histology. Whether an improved BMD with adynamic bone histology is useful in maintaining long-term bone health in renal transplant recipients requires further study.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/01.asn.0000087092.53894.80DOI Listing
October 2003
-->