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1.
Environ Microbiol ; 18(11): 4144-4152, 2016 11.
Article in English | MEDLINE | ID: mdl-27491006

ABSTRACT

The co-evolution of bacterial plant pathogens and their hosts is a complex and dynamic process. Host resistance imposes stress on invading pathogens that can lead to changes in the bacterial genome enabling the pathogen to escape host resistance. We have observed this phenomenon with the plant pathogen Pseudomonas syringae pv. phaseolicola where isolates that have lost the genomic island PPHGI-1 carrying the effector gene avrPphB from its chromosome are infective against previously resistant plant hosts. However, we have never observed island extinction from the pathogen population within a host suggesting the island is maintained. Here, we present a mathematical model which predicts different possible fates for the island in the population; one outcome indicated that PPHGI-1 would be maintained at low frequency in the population long term, if it confers a fitness benefit. We empirically tested this prediction and determined that PPHGI-1 frequency in the bacterial population drops to a low but consistently detectable level during host resistance. Once PPHGI-1-carrying cells encounter a susceptible host, they rapidly increase in the population in a negative frequency-dependent manner. Importantly, our data show that mobile genetic elements can persist within the bacterial population and increase in frequency under favourable conditions.


Subject(s)
Genomic Islands , Plant Diseases/microbiology , Pseudomonas syringae/genetics , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Plants/microbiology , Pseudomonas syringae/growth & development , Pseudomonas syringae/metabolism
2.
Pharmaceutics ; 15(7)2023 Jul 03.
Article in English | MEDLINE | ID: mdl-37514055

ABSTRACT

Infection with Fasciola hepatica (liver fluke) causes fasciolosis (or fascioliasis) and poses a considerable economic as well as welfare burden to both the agricultural and animal health sectors. Here, we explore the ex vivo anthelmintic potential of synthetic derivatives of hederagenin, isolated in bulk from Hedera helix. Thirty-six compounds were initially screened against F. hepatica newly excysted juveniles (NEJs) of the Italian strain. Eleven of these compounds were active against NEJs and were selected for further study, using adult F. hepatica derived from a local abattoir (provenance unknown). From these eleven compounds, six demonstrated activity and were further assessed against immature liver flukes of the Italian strain. Subsequently, the most active compounds (n = 5) were further evaluated in ex vivo dose response experiments against adult Italian strain liver flukes. Overall, MC042 was identified as the most active molecule and the EC50 obtained from immature and adult liver fluke assays (at 24 h post co-culture) are estimated as 1.07 µM and 13.02 µM, respectively. When compared to the in vitro cytotoxicity of MDBK bovine cell line, MC042 demonstrated the highest anthelmintic selectivity (44.37 for immature and 3.64 for adult flukes). These data indicate that modified hederagenins display properties suitable for further investigations as candidate flukicides.

3.
Vet Parasitol ; 309: 109766, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35926239

ABSTRACT

Control of liver fluke infections remains a significant challenge in the livestock sector due to widespread distribution of drug resistant parasite populations. In particular, increasing prevalence and economic losses due to infection with Fasciola hepatica is a direct result of drug resistance to the gold standard flukicide, triclabendazole. Sustainable control of this significant zoonotic pathogen, therefore, urgently requires the identification of new anthelmintics. Plants represent a source of molecules with potential flukicidal effects and, amongst their secondary metabolites, the diterpenoid abietic acids can be isolated in large quantities. In this study, nineteen (19) chemically modified abietic acid analogues (MC_X) were first evaluated for their anthelmintic activities against F. hepatica newly excysted juveniles (NEJs, from the laboratory-derived Italian strain); from this, 6 analogues were secondly evaluated for their anthelmintic activities against adult wild strain flukes. One analogue, MC010, was progressed further against 8-week immature- and 12-week mature Italian strain flukes. Here, MC010 demonstrated moderate activity against both of these intra-mammalian fluke stages (with an adult fluke EC50 = 12.97 µM at 72 h post culture). Overt mammalian cell toxicity of MC010 was inferred from the Madin-Darby bovine kidney (MDBK) cell line (CC50 = 17.52 µM at 24 h post culture) and demonstrated that medicinal chemistry improvements are necessary before abietic acid analogues could be considered as potential anthelmintics against liver fluke pathogens.


Subject(s)
Anthelmintics , Cattle Diseases , Fasciola hepatica , Fascioliasis , Abietanes/metabolism , Abietanes/pharmacology , Abietanes/therapeutic use , Animals , Anthelmintics/therapeutic use , Benzimidazoles/pharmacology , Cattle , Cattle Diseases/drug therapy , Fascioliasis/drug therapy , Fascioliasis/parasitology , Fascioliasis/veterinary , Mammals , Triclabendazole/pharmacology
4.
Mol Metab ; 60: 101487, 2022 06.
Article in English | MEDLINE | ID: mdl-35378329

ABSTRACT

OBJECTIVE: Fibrotic organ responses have recently been identified as long-term complications in diabetes. Indeed, insulin resistance and aberrant hepatic lipid accumulation represent driving features of progressive non-alcoholic fatty liver disease (NAFLD), ranging from simple steatosis and non-alcoholic steatohepatitis (NASH) to fibrosis. Effective pharmacological regimens to stop progressive liver disease are still lacking to-date. METHODS: Based on our previous discovery of transforming growth factor beta-like stimulated clone (TSC)22D4 as a key driver of insulin resistance and glucose intolerance in obesity and type 2 diabetes, we generated a TSC22D4-hepatocyte specific knockout line (TSC22D4-HepaKO) and exposed mice to control or NASH diet models. Mechanistic insights were generated by metabolic phenotyping and single-nuclei RNA sequencing. RESULTS: Hepatic TSC22D4 expression was significantly correlated with markers of liver disease progression and fibrosis in both murine and human livers. Indeed, hepatic TSC22D4 levels were elevated in human NASH patients as well as in several murine NASH models. Specific genetic deletion of TSC22D4 in hepatocytes led to reduced liver lipid accumulation, improvements in steatosis and inflammation scores and decreased apoptosis in mice fed a lipogenic MCD diet. Single-nuclei RNA sequencing revealed a distinct TSC22D4-dependent gene signature identifying an upregulation of mitochondrial-related processes in hepatocytes upon loss of TSC22D4. An enrichment of genes involved in the TCA cycle, mitochondrial organization, and triglyceride metabolism underscored the hepatocyte-protective phenotype and overall decreased liver damage as seen in mouse models of hepatocyte-selective TSC22D4 loss-of-function. CONCLUSIONS: Together, our data uncover a new connection between targeted depletion of TSC22D4 and intrinsic metabolic processes in progressive liver disease. Hepatocyte-specific reduction of TSC22D4 improves hepatic steatosis and promotes hepatocyte survival via mitochondrial-related mechanisms thus paving the way for targeted therapies.


Subject(s)
Diabetes Mellitus, Type 2 , Insulin Resistance , Non-alcoholic Fatty Liver Disease , Animals , Diabetes Mellitus, Type 2/metabolism , Fibrosis , Hepatocytes/metabolism , Humans , Lipids , Mice , Mice, Inbred C57BL , Mitochondria/metabolism , Non-alcoholic Fatty Liver Disease/metabolism , Transcription Factors/metabolism
5.
J Pharmacol Exp Ther ; 336(2): 468-78, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21036913

ABSTRACT

Nitric oxide (NO) derived from neuronal nitric-oxide synthase (nNOS) and inducible nitric-oxide synthase (iNOS) plays a key role in various pain and inflammatory states. KLYP961 (4-((2-cyclobutyl-1H-imidazo[4,5-b]pyrazin-1-yl)methyl)-7,8-difluoroquinolin-2(1H)-one) inhibits the dimerization, and hence the enzymatic activity of human, primate, and murine iNOS and nNOS (IC(50) values 50-400 nM), with marked selectivity against endothelial nitric-oxide synthase (IC(50) >15,000 nM). It has ideal drug like-properties, including excellent rodent and primate pharmacokinetics coupled with a minimal off-target activity profile. In mice, KLYP961 attenuated endotoxin-evoked increases in plasma nitrates, a surrogate marker of iNOS activity in vivo, in a sustained manner (ED(50) 1 mg/kg p.o.). KLYP961 attenuated pain behaviors in a mouse formalin model (ED(50) 13 mg/kg p.o.), cold allodynia in the chronic constriction injury model (ED(50) 25 mg/kg p.o.), or tactile allodynia in the spinal nerve ligation model (ED(50) 30 mg/kg p.o.) with similar efficacy, but superior potency relative to gabapentin, pregabalin, or duloxetine. Unlike morphine, the antiallodynic activity of KLYP961 did not diminish upon repeated dosing. KLYP961 also attenuated carrageenin-induced edema and inflammatory hyperalgesia and writhing response elicited by phenylbenzoquinone with efficacy and potency similar to those of celecoxib. In contrast to gabapentin, KLYP961 did not impair motor coordination at doses as high as 1000 mg/kg p.o. KLYP961 also attenuated capsaicin-induced thermal allodynia in rhesus primates in a dose-related manner with a minimal effective dose (≤ 10 mg/kg p.o.) and a greater potency than gabapentin. In summary, KLYP961 represents an ideal tool with which to probe the physiological role of NO derived from iNOS and nNOS in human pain and inflammatory states.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Enzyme Inhibitors/pharmacology , Fluoroquinolones/pharmacology , Nitric Oxide Synthase Type II/antagonists & inhibitors , Nitric Oxide Synthase Type I/antagonists & inhibitors , Pyrazines/pharmacology , Analgesics/pharmacology , Animals , Cells, Cultured , Cytochrome P-450 Enzyme Inhibitors , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/toxicity , Fluoroquinolones/pharmacokinetics , Fluoroquinolones/toxicity , Gastrointestinal Transit/drug effects , Humans , Macaca mulatta , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Motor Activity/drug effects , Protein Multimerization , Pyrazines/pharmacokinetics , Pyrazines/toxicity
6.
Environ Sci Pollut Res Int ; 28(39): 55634-55642, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34142320

ABSTRACT

The present study was conducted to assess the effect of toxicity of cadmium (Cd) on growth, tolerance index (TI), antioxidant activities, and malondialdehyde (MDA) content in two contrasting wild castor accessions (16-024 and S2-4) via hydroponic experiment (0 and 100 mg/L Cd). The results showed that Cd significantly reduced the growth rate, seedling height, root length, and shoot length of the castor accessions compared to the control, with the Cd effect being more severe in S2-4 than in 16-024. In addition, biomass response including the root and shoot fresh weight and root dry weight decreased in both accessions compared to the control. Compared to the control group, the shoot dry weight of accession S2-4 declined by 21.7%, whereas there was no change in 16-024, suggesting a level of tolerance in 16-024. Analysis of TI on all the growth parameters and biomass content revealed that accession 16-024 was highly tolerant to Cd stress than S2-4. The results further revealed that the expression of the antioxidant enzymes, viz., superoxide dismutase (SOD), catalase (CAT), non-enzymatic antioxidant, glutathione, and MDA content, was influenced by genotype. S2-4 exhibited a higher antioxidant activity (SOD, CAT) and lipid peroxidation activity than 16-024, indicative of oxidative damage from Cd stress.


Subject(s)
Cadmium , Ricinus , Antioxidants , Cadmium/toxicity , Lipid Peroxidation
7.
Nano Lett ; 9(5): 1937-43, 2009 May.
Article in English | MEDLINE | ID: mdl-19354278

ABSTRACT

The unique electronic properties of single-walled carbon nanotubes (SWNTs) make them promising candidates for next generation electronics, particularly in systems that demand high frequency (e.g., radio frequency, RF) operation. Transistors that incorporate perfectly aligned, parallel arrays of SWNTs avoid the practical limitations of devices that use individual tubes, and they also enable comprehensive experimental and theoretical evaluation of the intrinsic properties. Thus, devices consisting of arrays represent a practical route to use of SWNTs for RF devices and circuits. The results presented here reveal many aspects of device operation in such array layouts, including full compatibility with conventional small signal models of RF response. Submicrometer channel length devices show unity current gain (f(t)) and unity power gain frequencies (f(max)) as high as approximately 5 and approximately 9 GHz, respectively, with measured scattering parameters (S-parameters) that agree quantitatively with calculation. The small signal models of the devices provide the essential intrinsic parameters: saturation velocities of 1.2 x 10(7) cm/s and intrinsic values of f(t) of approximately 30 GHz for a gate length of 700 nm, increasing with decreasing length. The results provide clear insights into the challenges and opportunities of SWNT arrays for applications in RF electronics.

8.
J Med Chem ; 63(21): 12992-13012, 2020 11 12.
Article in English | MEDLINE | ID: mdl-33119286

ABSTRACT

Ionizable cationic lipids are critical components involved in nanoparticle formulations, which are utilized in delivery platforms for RNA therapeutics. While general criteria regarding lipophilicity and measured pKa in formulation are understood to have impacts on utility in vivo, greater granularity with respect to the impacts of the structure on calculated and measured physicochemical parameters and the subsequent performance of those ionizable cationic lipids in in vivo studies would be beneficial. Herein, we describe structural alterations made within a lipid class exemplified by 4, which allow us to tune calculated and measured physicochemical parameters for improved performance, resulting in substantial improvements versus the state of the art at the outset of these studies, resulting in good in vivo activity within a range of measured basicity (pKa = 6.0-6.6) and lipophilicity (cLogD = 10-14).


Subject(s)
Lipids/chemistry , RNA, Small Interfering/metabolism , Transfection/methods , Animals , Cations/chemistry , Factor VII/antagonists & inhibitors , Factor VII/genetics , Factor VII/metabolism , Female , Humans , Kinetics , Lipids/chemical synthesis , Mice , Nanoparticles/chemistry , Particle Size , RNA Interference , RNA Stability , RNA, Small Interfering/blood , Structure-Activity Relationship
9.
Mol Pharmacol ; 76(1): 153-62, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19364813

ABSTRACT

Nitric-oxide synthases (NOS) generate nitric oxide (NO) through the oxidation of l-arginine. Inappropriate or excessive production of NO by NOS is associated with the pathophysiology of various disease states. Efforts to treat these disorders by developing arginine mimetic, substrate-competitive NOS inhibitors as drugs have met with little success. Small-molecule-mediated inhibition of NOS dimerization represents an intriguing alternative to substrate-competitive inhibition. An ultra-high-throughput cell-based screen of 880,000 small molecules identified a novel quinolinone with inducible NOS (iNOS) inhibitory activity. Exploratory chemistry based on this initial screening hit resulted in the synthesis of KLYP956, which inhibits iNOS at low nanomolar concentrations. The iNOS inhibitory potency of KLYP956 is insensitive to changes in concentrations of the substrate arginine, or the cofactor tetrahydrobiopterin. Mechanistic analysis suggests that KLYP956 binds the oxygenase domain in the vicinity of the active site heme and inhibits iNOS and neuronal NOS (nNOS) by preventing the formation of enzymatically active dimers. Oral administration of KLYP956 [N-(3-chlorophenyl)-N-((8-fluoro-2-oxo-1,2-dihydroquinolin-4-yl)methyl)-4-methylthiazole-5-carboxamide] inhibits iNOS activity in a murine model of endotoxemia and blocks pain behaviors in a formalin model of nociception. KLYP956 thus represents the first nonimidazole-based inhibitor of iNOS and nNOS dimerization and provides a novel pharmaceutical alternative to previously described substrate competitive inhibitors.


Subject(s)
Enzyme Inhibitors/pharmacology , Fluoroquinolones/pharmacology , Nitric Oxide Synthase/antagonists & inhibitors , Thiazoles/pharmacology , Administration, Oral , Animals , Cells, Cultured , Dimerization , Humans , Mice , Nitric Oxide/biosynthesis , Nitric Oxide Synthase/chemistry , Nitric Oxide Synthase Type I/chemistry , Nitric Oxide Synthase Type II/chemistry , Pain/drug therapy , Species Specificity
10.
Mol Cancer Ther ; 7(6): 1494-505, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18566220

ABSTRACT

Histone deacetylase inhibitors have emerged as promising anticancer drugs. Using an unbiased ultrahigh throughput screening system, a novel mercaptoketone-based histone deacetylase inhibitor series was identified that was optimized to the lead compound, KD5170. KD5170 inhibited the proliferation of myeloma cell lines and the viability of CD138(+) primary myeloma cells by induction of apoptosis, accompanied by an increase of acetylation of histones and activation of caspase-3, caspase-8, and caspase-9. Treatment with KD5170 caused a loss of mitochondrial membrane potential resulting in release of apoptogenic factors such as cytochrome c, Smac, and apoptosis-inducing factor. Furthermore, KD5170 induced oxidative stress and oxidative DNA damage in myeloma cells as evidenced by the up-regulation of heme oxygenase-1 and H2A.X phosphorylation. Combination of KD5170 with proteasome inhibitor bortezomib or tumor necrosis factor-related apoptosis-inducing ligand synergistically enhanced the antimyeloma activity. We further found that resistance of myeloma cells to KD5170 was associated with activation of the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway under treatment with KD5170. Pretreatment with the mitogen-activated protein kinase inhibitor U0126 restored sensitivity to KD5170, suggesting that the combination of KD5170 with U0126 could overcome drug resistance. Growth of myeloma tumor xenografts in KD5170-treated nude mice was significantly inhibited and survival was prolonged. Histone acetylation was increased in spleen and tumor tissues of animals treated with KD5170. Our data indicate that KD5170 has potent antimyeloma activity in vitro and in vivo, which is mediated by DNA damage and mitochondrial signaling and subsequent induction of apoptosis.


Subject(s)
DNA Damage , Enzyme Inhibitors/pharmacology , Histone Deacetylase Inhibitors , Ketones/pharmacology , Mitochondria/metabolism , Multiple Myeloma/enzymology , Pyridines/pharmacology , Signal Transduction/drug effects , Sulfonamides/pharmacology , Acetylation/drug effects , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Apoptosis Regulatory Proteins/metabolism , Boronic Acids/pharmacology , Bortezomib , Caspases/metabolism , Cell Line, Tumor , Drug Resistance, Neoplasm/drug effects , Drug Synergism , Enzyme Activation/drug effects , Enzyme Inhibitors/chemistry , Histones/metabolism , Humans , Ketones/chemistry , Membrane Potential, Mitochondrial/drug effects , Mice , Mitochondria/drug effects , Oxidative Stress/drug effects , Protein Transport/drug effects , Pyrazines/pharmacology , Pyridines/chemistry , Sulfonamides/chemistry , TNF-Related Apoptosis-Inducing Ligand/pharmacology , Xenograft Model Antitumor Assays , bcl-2-Associated X Protein/metabolism
11.
Mol Cancer Ther ; 7(5): 1054-65, 2008 May.
Article in English | MEDLINE | ID: mdl-18483295

ABSTRACT

Histone deacetylase (HDAC) inhibitors have garnered significant attention as cancer drugs. These therapeutic agents have recently been clinically validated with the market approval of vorinostat (SAHA, Zolinza) for treatment of cutaneous T-cell lymphoma. Like vorinostat, most of the small-molecule HDAC inhibitors in clinical development are hydroxamic acids, whose inhibitory activity stems from their ability to coordinate the catalytic Zn2+ in the active site of HDACs. We sought to identify novel, nonhydroxamate-based HDAC inhibitors with potentially distinct pharmaceutical properties via an ultra-high throughput small molecule biochemical screen against the HDAC activity in a HeLa cell nuclear extract. An alpha-mercaptoketone series was identified and chemically optimized. The lead compound, KD5170, exhibits HDAC inhibitory activity with an IC50 of 0.045 micromol/L in the screening biochemical assay and an EC50 of 0.025 micromol/L in HeLa cell-based assays that monitor histone H3 acetylation. KD5170 also exhibits broad spectrum classes I and II HDAC inhibition in assays using purified recombinant human isoforms. KD5170 shows significant antiproliferative activity against a variety of human tumor cell lines, including the NCI-60 panel. Significant tumor growth inhibition was observed after p.o. dosing in human HCT-116 (colorectal cancer), NCI-H460 (non-small cell lung carcinoma), and PC-3 (prostate cancer) s.c. xenografts in nude mice. In addition, a significant increase in antitumor activity and time to end-point occurred when KD5170 was combined with docetaxel in xenografts of the PC-3 prostate cancer cell line. The biological and pharmaceutical profile of KD5170 supports its continued preclinical and clinical development as a broad spectrum anticancer agent.


Subject(s)
Antineoplastic Agents/pharmacology , Enzyme Inhibitors/pharmacology , Histone Deacetylase Inhibitors , Pyridines/pharmacology , Sulfonamides/pharmacology , Animals , Cell Line, Tumor , Colorectal Neoplasms/drug therapy , Drug Screening Assays, Antitumor , Female , Humans , Inhibitory Concentration 50 , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Prostatic Neoplasms/drug therapy , Xenograft Model Antitumor Assays
12.
Bioorg Med Chem Lett ; 18(23): 6093-6, 2008 Dec 01.
Article in English | MEDLINE | ID: mdl-18954983

ABSTRACT

We report the identification of KD5170, a potent mercaptoketone-based Class I and II-histone deacetylase inhibitor that demonstrates broad spectrum cytotoxic activity against a range of human tumor-derived cell lines. KD5170 exhibits robust and sustained histone H3 hyperacetylation in HCT-116 xenograft tumors following single oral or i.v. dose and inhibition of tumor growth following chronic dosing.


Subject(s)
Antineoplastic Agents/pharmacology , Enzyme Inhibitors/pharmacology , Histone Deacetylase Inhibitors , Prodrugs/pharmacology , Pyridines/pharmacology , Sulfonamides/pharmacology , Animals , Antineoplastic Agents/chemistry , Cell Line, Tumor , Drug Screening Assays, Antitumor , HCT116 Cells , Humans , Inhibitory Concentration 50 , Mice , Mice, Nude , Molecular Structure , Prodrugs/chemistry , Pyridines/chemistry , Structure-Activity Relationship , Sulfonamides/chemistry , Xenograft Model Antitumor Assays
13.
Neuro Oncol ; 19(3): 372-382, 2017 03 01.
Article in English | MEDLINE | ID: mdl-27765835

ABSTRACT

Background: Previously we showed therapeutic efficacy of unprotected miR-124 in preclinical murine models of glioblastoma, including in heterogeneous genetically engineered murine models by exploiting the immune system and thereby negating the need for direct tumor delivery. Although these data were promising, to implement clinical trials, we required a scalable formulation that afforded protection against circulatory RNases. Methods: We devised lipid nanoparticles that encapsulate and protect the miRs from degradation and provide enhanced delivery into the immune cell compartment and tested in vivo antitumor effects. Results: Treatment with nanoparticle-encapsulated miR-124, LUNAR-301, demonstrated a median survival exceeding 70 days, with an associated reversal of tumor-mediated immunosuppression and induction of immune memory. In both canine and murine models, the safety profile of LUNAR-301 was favorable. Conclusions: For the first time, we show that nanoparticles can direct a therapeutic response by targeting intracellular immune pathways. Although shown in the context of gliomas, this therapeutic approach would be applicable to other malignancies.


Subject(s)
Brain Neoplasms/therapy , Glioma/therapy , Immune Tolerance/genetics , Lipids/chemistry , MicroRNAs/genetics , Nanoparticles/administration & dosage , Animals , Brain Neoplasms/genetics , Brain Neoplasms/immunology , Dogs , Glioma/genetics , Glioma/immunology , Humans , Immunologic Memory/genetics , Mice , Mice, Inbred C57BL , MicroRNAs/administration & dosage , Nanoparticles/chemistry , Tumor Cells, Cultured , Xenograft Model Antitumor Assays
14.
J Med Chem ; 53(21): 7739-55, 2010 Nov 11.
Article in English | MEDLINE | ID: mdl-20931971

ABSTRACT

Three isoforms of nitric oxide synthase (NOS), dimeric enzymes that catalyze the formation of nitric oxide (NO) from arginine, have been identified. Inappropriate or excessive NO produced by iNOS and/or nNOS is associated with inflammatory and neuropathic pain. Previously, we described the identification of a series of amide-quinolinone iNOS dimerization inhibitors that although potent, suffered from high clearance and limited exposure in vivo. By conformationally restricting the amide of this progenitor series, we describe the identification of a novel series of benzimidazole-quinolinone dual iNOS/nNOS inhibitors with low clearance and sustained exposure in vivo. Compounds were triaged utilizing an LPS challenge assay coupled with mouse and rhesus pharmacokinetics and led to the identification of 4,7-imidazopyrazine 42 as the lead compound. 42 (KD7332) (J. Med. Chem. 2009, 52, 3047 - 3062) was confirmed as an iNOS dimerization inhibitor and was efficacious in the mouse formalin model of nociception and Chung model of neuropathic pain, without showing tolerance after repeat dosing. Further 42 did not affect motor coordination up to doses of 1000 mg/kg, demonstrating a wide therapeutic margin.


Subject(s)
Analgesics/chemical synthesis , Fluoroquinolones/chemical synthesis , Nitric Oxide Synthase Type II/antagonists & inhibitors , Nitric Oxide Synthase Type I/antagonists & inhibitors , Pain/drug therapy , Pyrazines/chemical synthesis , Administration, Oral , Analgesics/chemistry , Analgesics/pharmacology , Animals , Cell Line , Drug Tolerance , Fluoroquinolones/chemistry , Fluoroquinolones/pharmacology , Humans , In Vitro Techniques , Mice , Microsomes, Liver/metabolism , Pain/etiology , Pain Measurement , Peripheral Nervous System Diseases/drug therapy , Peripheral Nervous System Diseases/etiology , Protein Multimerization , Pyrazines/chemistry , Pyrazines/pharmacology , Rotarod Performance Test , Structure-Activity Relationship
15.
J Med Chem ; 52(9): 3047-62, 2009 May 14.
Article in English | MEDLINE | ID: mdl-19374401

ABSTRACT

There are three isoforms of dimeric nitric oxide synthases (NOS) that convert arginine to citrulline and nitric oxide. Inducible NOS is implicated in numerous inflammatory diseases and, more recently, in neuropathic pain states. The majority of existing NOS inhibitors are either based on the structure of arginine or are substrate competitive. We describe the identification from an ultra high-throughput screen of a novel series of quinolinone small molecule, nonarginine iNOS dimerization inhibitors. SAR studies on the screening hit, coupled with an in vivo lipopolysaccharide (LPS) challenge assay measuring plasma nitrates and drug levels, rapidly led to the identification of compounds 12 and 42--potent inhibitors of the human and mouse iNOS enzyme that were highly selective over endothelial NOS (eNOS). Following oral dosing, compounds 12 and 42 gave a statistical reduction in pain behaviors in the mouse formalin model, while 12 also statistically reduced neuropathic pain behaviors in the chronic constriction injury (Bennett) model.


Subject(s)
Drug Discovery , Fluoroquinolones/administration & dosage , Fluoroquinolones/pharmacology , Nitric Oxide Synthase Type II/antagonists & inhibitors , Pain/drug therapy , Protein Multimerization/drug effects , Pyrazines/administration & dosage , Pyrazines/pharmacology , Quinolones/administration & dosage , Quinolones/pharmacology , Administration, Oral , Animals , Cell Line , Constriction, Pathologic/chemically induced , Constriction, Pathologic/drug therapy , Disease Models, Animal , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Fluoroquinolones/chemistry , Fluoroquinolones/therapeutic use , Formaldehyde/toxicity , Humans , Inhibitory Concentration 50 , Lipopolysaccharides/toxicity , Mice , Nitric Oxide Synthase Type II/chemistry , Nitric Oxide Synthase Type II/metabolism , Protein Structure, Quaternary , Pyrazines/chemistry , Pyrazines/therapeutic use , Quinolones/chemistry , Quinolones/therapeutic use , Structure-Activity Relationship , Substrate Specificity
16.
J Med Chem ; 52(14): 4173-91, 2009 Jul 23.
Article in English | MEDLINE | ID: mdl-19552437

ABSTRACT

Evidence suggests that corticotropin-releasing factor-1 (CRF(1)) receptor antagonists may offer therapeutic potential for the treatment of diseases associated with elevated levels of CRF such as anxiety and depression. A pyrazinone-based chemotype of CRF(1) receptor antagonists was discovered. Structure-activity relationship studies led to the identification of numerous potent analogues including 12p, a highly potent and selective CRF(1) receptor antagonist with an IC(50) value of 0.26 nM. The pharmacokinetic properties of 12p were assessed in rats and Cynomolgus monkeys. Compound 12p was efficacious in the defensive withdrawal test (an animal model of anxiety) in rats. The synthesis, structure-activity relationships and in vivo properties of compounds within the pyrazinone chemotype are described.


Subject(s)
Pyrazines/chemistry , Pyrazines/pharmacology , Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors , Animals , Cell Line, Tumor , Humans , Macaca fascicularis , Male , Pyrazines/chemical synthesis , Pyrazines/pharmacokinetics , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship
17.
Int J Dermatol ; 45(3): 314-5, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16533238

ABSTRACT

A 41-year-old white female with a past medical history of hypothyroidism and alopecia universalis presented on January 24, 2002 with a recently changing mole. She indicated changes in size and color of the superior aspect of a mole that had been present for more than 8 years. She had approximately 20 lifetime peeling sunburns due to being a lifeguard. No family or previous personal history of skin cancers, including melanoma or atypical nevi, was reported. Her history of alopecia universalis began 12 years previously and has partially resolved with remaining patchy alopecia of the scalp and eyebrows. On diagnosis of alopecia universalis, she was initially treated with oral prednisone for 1 year and topical minoxidil for 3 months. Currently, she is not being treated for this condition. She denied other previous skin conditions. She had a surgical history of tonsillectomy at the age of 7 years. Her current medication includes levothyroxine (0.015 microg) for hypothyroidism diagnosed 12 years previously. She reported no known drug allergies. During the initial physical examination, she presented with phototype II skin with two adjacent pigmented lesions on her left foot within a 1.3 cm square. The first lesion on the left posterior distal heel was an irregular, brown-black, 0.5 x 0.6 cm macule. The second lesion, on the left posterior proximal heel, was an irregular, brown, speckled, 0.3 x 0.4 cm macule (Fig. 1). The patient had ophiasis of the scalp and total alopecia of the bilateral eyebrows. In keeping with the patient's wishes, alopecia lesions were not biopsied and clinical photographs of the alopecia are not included in this article. Two 3 mm punch biopsies were performed within each lesion. The left posterior proximal lesion showed malignant melanoma, with a Breslow depth of 0.4 mm, anatomic level II, marked lymphocytic response and partial regression (Fig. 2). The left posterior distal lesion showed malignant melanoma in situ, arising in a lentiginous compound nevus, with architectural disorder and cytological atypia. These two lesions were concluded to be one lesion with clinical regression. She underwent local excision with 1-cm margins and sentinel lymph node biopsy owing to the presence of regression, which showed no evidence of metastatic melanoma. Lactate dehydrogenase and chest X-ray were within normal limits. The alopecia areas were not biopsied previously or at that time.


Subject(s)
Alopecia Areata/complications , Melanoma/pathology , Skin Neoplasms/pathology , Skin/pathology , Adult , Biopsy , Female , Humans , Hypothyroidism/complications , Melanoma/surgery , Remission, Spontaneous , Sentinel Lymph Node Biopsy , Skin Neoplasms/surgery
18.
Bioorg Med Chem Lett ; 15(9): 2259-63, 2005 May 02.
Article in English | MEDLINE | ID: mdl-15837305

ABSTRACT

Interest in water soluble COX-2 inhibitors that can be administered intravenously led to the development of novel pro-drugs of a furanone based COX-2 inhibitor 2. Transforming the lactone moiety of the furanone to an imidate or an ortho-ester with a hydrophilic, endogenous appendage resulted in water soluble pro-drugs that converted to the parent drug in vivo.


Subject(s)
Cyclooxygenase Inhibitors/chemical synthesis , Lactones/chemical synthesis , Prodrugs/chemical synthesis , Prostaglandin-Endoperoxide Synthases/metabolism , Cyclooxygenase 2 , Cyclooxygenase 2 Inhibitors , Cyclooxygenase Inhibitors/chemistry , Cyclooxygenase Inhibitors/pharmacology , Esters , Furans , Imides , Indicators and Reagents , Lactones/chemistry , Lactones/pharmacology , Models, Molecular , Molecular Structure , Prodrugs/chemistry , Prodrugs/pharmacology , Solubility
20.
Gynecol Oncol ; 90(1): 200-3, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12821365

ABSTRACT

BACKGROUND: While acute gastric dilation is a postoperative complication familiar to most surgeons, massive dilatation with necrosis and rupture is a very rare event. We performed a computer search in the MEDLINE database for the years 1966-2001 for articles published in any language using the key words gastric dilation, gastric necrosis, intestinal obstruction, and gynecologic surgery. Our search yielded no reports of massive gastric dilation and ischemic necrosis from a small bowel obstruction following gynecologic surgery. CASE: A 76-year-old woman developed massive gastric dilatation with ischemic necrosis associated with small bowel obstruction following gynecologic surgery for benign disease. CONCLUSION: Gynecologists should be aware of the entity. Early diagnosis and treatment are essential to minimize morbidity and mortality.


Subject(s)
Gastric Dilatation/complications , Gynecologic Surgical Procedures/adverse effects , Intestinal Obstruction/complications , Stomach/pathology , Aged , Female , Gastric Dilatation/pathology , Humans , Necrosis
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