ABSTRACT
BACKGROUND: Pemphigus herpetiformis (PH) is a rare clinical subtype of pemphigus with the presence of urticarial plaques, severe pruritus, rare acantholysis and eosinophilic spongiosis. OBJECTIVES: The aim of this study was to investigate the influence of IL-31 and pro-inflammatory cytokines/chemokines in the pathogenesis of PH. METHODS: Twenty-five patients with PH and three groups: pemphigus foliaceus (PF = 14), pemphigus vulgaris (PV = 15) and healthy controls (HC = 20) were selected for this study. The groups were analysed by immunohistochemistry utilizing IL-31, IL-31RA, IL-4, IL-17 and TNF-α antibodies. Serum levels of IL-4, IL-13, TNF, CXCL8, CCL5 and CCL2 were evaluated by cytometric bead array. RESULTS: Analysis of IL-31 family of PH patients revealed the following findings: (i) Enhanced in situ expression of IL-31 in PH samples, compared to PF and to PV (epidermis); (ii) Cutaneous IL-31RA expression in PH samples was higher than in PF, PV and HC groups (epidermis and dermis); (iii) PF patients that evolved to PH showed significant increased IL-31RA epidermal expression during the PH phase. Profile of pro-inflammatory cytokines (IL-4, IL-17 and TNF-α) in PH patients' skin exhibited: (i) Enhanced IL-4 expression, when compared to patients with PF (epidermis and dermis) and with PV (epidermis); (ii) Augmented IL-17 expression than PF and PV patients (epidermis); (iii) Augmented expression of TNF-α when compared to PF at the epidermal level. Evaluation of circulating cytokines and chemokines showed higher levels of CXCL8 and CCL2 in PH sera compared to HC group. CONCLUSIONS: IL-31 and IL-31RA, cytokines related to pruritus, and pro-inflammatory chemokines (CXCL8 and CCL2) seem to exert a role in the pathogenesis of PH. These findings support future studies to clarify the role of IL-31 pathway as a potential therapeutic target for patients with PH.
Subject(s)
Autoimmune Diseases , Pemphigus , Acantholysis , Chemokine CCL2 , Cytokines , Humans , Interleukin-13Subject(s)
Pemphigus/metabolism , Receptors, Adrenergic, beta-1/metabolism , Receptors, Adrenergic, beta-2/metabolism , Receptors, Adrenergic, beta-3/metabolism , Case-Control Studies , Dermatitis, Exfoliative/etiology , Dermatitis, Exfoliative/metabolism , Epidermis/metabolism , Humans , Keratinocytes/metabolism , Pemphigus/complicationsABSTRACT
BACKGROUND: Erythroderma is a severe manifestation of pemphigus foliaceus (PF), a blistering disease mediated by IgG autoantibodies against desmoglein 1. Increasing evidence supports the contribution of angiogenic mediators in the pathogenesis of erythroderma. OBJECTIVE: To evaluate the in situ expression of vascular endothelial growth factor (VEGF) and endoglin in patients with PF with erythroderma. METHODS: Formalin-fixed paraffin-embedded skin samples obtained from patients with erythrodermic PF (n = 19; 12 patients with endemic PF), non-erythrodermic PF (n = 17), pemphigus vulgaris (PV; n = 10), psoriasis (n = 10) and healthy individuals (HI; n = 10) were processed in an automated immunohistochemistry platform utilizing anti-VEGF and anti-endoglin as primary antibodies. Reactivity was evaluated both manually (0 = negative; 1+ = mild; 2+ = intense) and through an automated microvessel analysis algorithm. RESULTS: Vascular endothelial growth factor expression in erythrodermic PF was higher than in non-erythrodermic PF (P = 0.034) and in HI (P = 0.004), and similar to psoriasis (P = 0.667) and PV (P = 0.667). In non-erythrodermic PF, VEGF positivity was similar to HI (P = 0.247), and lower than psoriasis (P = 0.049) and PV (P = 0.049). Both erythrodermic and non-erythrodermic PF presented similar endoglin expression (P = 0.700). In addition, endoglin positivity during erythrodermic PF was similar to psoriasis (P = 0.133) and lower than PV (P = 0.0009). Increased expression of in situVEGF suggests that healing processes are triggered in response to tissue damage led by autoantibodies in PF, especially during erythroderma. Reduced endoglin positivity suggests that an unbalanced angiogenesis may occur during erythrodermic PF. Further studies may help to confirm if the regulation of VEGF and endoglin expression in patients with PF can contribute to control the healing process and enable disease remission. CONCLUSION: Overexpression of VEGF in erythrodermic PF as well as in PV and psoriasis points out a dysregulated repair process in severe forms of these diseases and suggests VEGF and endoglin could act as prognostic markers and future therapeutic targets to enable proper healing in PF.
Subject(s)
Endoglin/metabolism , Pemphigus/pathology , Psoriasis/pathology , Vascular Endothelial Growth Factor A/metabolism , Adult , Aged , Biomarkers/metabolism , Biopsy, Needle , Case-Control Studies , Dermatitis, Exfoliative/metabolism , Dermatitis, Exfoliative/parasitology , Disease Progression , Female , Humans , Immunohistochemistry , Male , Middle Aged , Pemphigus/metabolism , Predictive Value of Tests , Prognosis , Psoriasis/metabolism , Reference Values , Retrospective Studies , Tissue EmbeddingABSTRACT
Chemical genetics has arisen as a powerful approach for identifying novel anti-cancer agents. However, a major bottleneck of this approach is identifying the targets of lead compounds that arise from screens. Here, we coupled the synthesis and screening of fragment-based cysteine-reactive covalent ligands with activity-based protein profiling (ABPP) chemoproteomic approaches to identify compounds that impair colorectal cancer pathogenicity and map the druggable hotspots targeted by these hits. Through this coupled approach, we discovered a cysteine-reactive acrylamide DKM 3-30 that significantly impaired colorectal cancer cell pathogenicity through targeting C1101 on reticulon 4 (RTN4). While little is known about the role of RTN4 in colorectal cancer, this protein has been established as a critical mediator of endoplasmic reticulum tubular network formation. We show here that covalent modification of C1101 on RTN4 by DKM 3-30 or genetic knockdown of RTN4 impairs endoplasmic reticulum and nuclear envelope morphology as well as colorectal cancer pathogenicity. We thus put forth RTN4 as a potential novel colorectal cancer therapeutic target and reveal a unique druggable hotspot within RTN4 that can be targeted by covalent ligands to impair colorectal cancer pathogenicity. Our results underscore the utility of coupling the screening of fragment-based covalent ligands with isoTOP-ABPP platforms for mining the proteome for novel druggable nodes that can be targeted for cancer therapy.
Subject(s)
Acrylamide/pharmacology , Antineoplastic Agents/pharmacology , Colorectal Neoplasms/drug therapy , Cysteine/chemistry , Endoplasmic Reticulum/drug effects , Nogo Proteins/antagonists & inhibitors , Proteomics , Acrylamide/chemistry , Antineoplastic Agents/chemistry , Colorectal Neoplasms/metabolism , Colorectal Neoplasms/pathology , Endoplasmic Reticulum/metabolism , Humans , Ligands , Nogo Proteins/genetics , Nogo Proteins/metabolism , Nuclear Envelope/drug effects , Nuclear Envelope/metabolismABSTRACT
BACKGROUND: Erythroderma is a clinical skin syndrome shared by patients with cutaneous disorders of distinct aetiologies as a result of the combined actions of chemokines, adhesion molecules, and cytokines, such as vascular endothelial growth factor (VEGF). OBJECTIVE: To evaluate the profile of serum levels of VEGF and soluble vascular endothelial growth factor receptor 1 (sVEGFR-1) in pemphigus foliaceus (PF) patients with erythroderma. METHODS: We conducted a retrospective study, which included (i) a chart review of all PF patients from the Autoimmune Blistering Clinic, University of Sao Paulo, Brazil, from January 1991 to December 2014, together with an evaluation of demographic variables, hospitalization duration and complications and (ii) analysis of the circulating VEGF and sVEGFR-1 levels in PF patients with erythroderma by ELISA. The controls included patients with pemphigus vulgaris or psoriasis. RESULTS: We observed higher serum VEGF levels in PF patients during erythroderma than during the non-erythrodermic phase. PF patients showed increased serum levels of sVEGFR-1 during the erythrodermic phase in comparison to controls. Interestingly, the sVEGFR-1 and antidesmoglein-1 levels were positively correlated during the non-erythrodermic period. CONCLUSION: Erythroderma, which represents one clinical form of PF, implies more severe outcomes. The circulating levels of VEGF, a potent endothelial activator, are increased in PF patients with erythroderma; this result suggests the contribution of the blood vessel endothelium to the pathogenesis of this clinical syndrome. Interestingly, our findings showed a positive correlation between the sVEGFR-1 and antidesmoglein-1 antibody levels, indicating a suppressive response to VEGF augmentation during the erythrodermic phase of PF.
Subject(s)
Dermatitis, Exfoliative/complications , Pemphigus/blood , Vascular Endothelial Growth Factor A/blood , Adult , Female , Humans , Male , Middle Aged , Pemphigus/complicationsABSTRACT
PurposeTo investigate the prevalence of microcystic macular edema (MME) in patients with glaucoma and the relationship between glaucomatous visual field defects and MME.Patients and methodsWe analyzed 636 eyes of 341 glaucoma patients who underwent spectral domain optical coherence tomography (SD-OCT). MME was defined as vacuoles observed in the inner nuclear layer (INL) on SD-OCT. Quantitative assessment of MME area was performed using en-face imaging obtained swept-source OCT (SS-OCT) and Adobe Photoshop CS6 Extended software. These values were compared with the visual field results with the Humphrey field analyzer.ResultsMME was observed in 1.6% of eyes. The visual field mean deviation (MD), pattern standard deviation (PSD) and visual acuity was significantly worse (P= 0.023, P=0.037, and P=0.018, respectively) in eyes with MME. The average MME area was 2.38±1.43%. There was no significant correlation between visual field deficits and MME area.ConclusionsThe MME detection rate based on general inspection was 1.6%. MME in glaucomatous eyes were associated with worse MD, PSD, and visual acuity. Further research is needed to increase the number of cases to allow for more detailed analysis.
Subject(s)
Glaucoma/diagnosis , Macular Edema/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Glaucoma/epidemiology , Humans , Intraocular Pressure/physiology , Macular Edema/epidemiology , Male , Middle Aged , Nerve Fibers/pathology , Prevalence , Retinal Ganglion Cells/pathology , Tomography, Optical Coherence , Tonometry, Ocular , Vacuoles/pathology , Vision Disorders/diagnosis , Visual Acuity/physiology , Visual FieldsABSTRACT
During tactile perception, long-range intracortical top-down axonal projections are essential for processing sensory information. Whether these projections regulate sleep-dependent long-term memory consolidation is unknown. We altered top-down inputs from higher-order cortex to sensory cortex during sleep and examined the consolidation of memories acquired earlier during awake texture perception. Mice learned novel textures and consolidated them during sleep. Within the first hour of non-rapid eye movement (NREM) sleep, optogenetic inhibition of top-down projecting axons from secondary motor cortex (M2) to primary somatosensory cortex (S1) impaired sleep-dependent reactivation of S1 neurons and memory consolidation. In NREM sleep and sleep-deprivation states, closed-loop asynchronous or synchronous M2-S1 coactivation, respectively, reduced or prolonged memory retention. Top-down cortical information flow in NREM sleep is thus required for perceptual memory consolidation.
Subject(s)
Memory Consolidation/physiology , Sleep, REM/physiology , Animals , Axons/physiology , Channelrhodopsins , Mice , Mice, Transgenic , Optogenetics , Perception , Recognition, Psychology , Sensorimotor Cortex/physiologyABSTRACT
Bordetella avium is a Gram negative upper respiratory tract pathogen of birds. B. avium infection of commercially raised turkeys is an agriculturally significant problem. Here we describe the functional analysis of the first characterized B. avium autotransporter protein, Baa1. Autotransporters comprise a large family of proteins found in all groups of Gram negative bacteria. Although not unique to pathogenic bacteria, autotransporters have been shown to perform a variety of functions implicated in virulence. To test the hypothesis that Baa1 is a B. avium virulence factor, unmarked baa1 deletion mutants (Δbaa1) were created and tested phenotypically. It was found that baa1 mutants have wild-type levels of serum sensitivity and infectivity, yet significantly lower levels of turkey tracheal cell attachment in vitro. Likewise, semi-purified recombinant His-tagged Baa1, expressed in Escherichia coli, was shown to bind specifically to turkey tracheal cells via western blot analysis. Taken together, we conclude that Baa1 acts as a host cell attachment factor and thus plays a role B. avium virulence.
Subject(s)
Bacterial Adhesion , Bacterial Proteins/metabolism , Bordetella Infections/veterinary , Bordetella avium/physiology , Poultry Diseases/microbiology , Animals , Bacterial Proteins/genetics , Bordetella Infections/microbiology , Bordetella avium/genetics , Bordetella avium/pathogenicity , Turkeys , VirulenceABSTRACT
Randomized trials of chemoradiation for esophageal cancer have included very few patients age > or = 75. In this retrospective study, we describe the outcomes and toxicity of full-dose chemoradiation in elderly patients with esophageal cancer. Patients, age > or = 75, treated with full-dose chemoradiation for esophageal carcinoma from 2002 to 2008 were retrospectively reviewed. Thirty-four patients were identified with a median age of 79.5 (range 75-89). The median Eastern Cooperative Oncology Group performance status was 1 (range 0-3) and the median Adult Comorbidity Evaluation-27 score was 1 (range 0-3). Twenty-eight patients received definitive and six received neoadjuvant chemoradiation. The median radiation dose delivered was 50.4 Gray (range 3.6-68.4 Gray). Platinum-based chemotherapy was used in 79.4% of patients. Fifty percent of the patients completed all planned radiation therapy (RT) and chemotherapy; 85.3% completed RT. Acute toxicity > or = grade 4 occurred in 38.2% of patients, and 70.6% of the patients required hospitalization, emergency department visit, and/or RT break. Median follow-up was 14.5 months among 7 survivors, and median survival was 12.0 months (95% confidence interval [CI]: 9.7 to 24.1 months). The actuarial overall survival at 2 years was 29.7% (95% CI: 16.6 to 52.6%). There were four treatment-related deaths. The median time to any recurrence was 10.4 months. Nineteen patients had a local and/or distant recurrence. In conclusion, elderly patients experienced substantial morbidity from chemoradiation, and long-term survival was low. Future efforts to improve treatment tolerability in the elderly are needed.
Subject(s)
Esophageal Neoplasms/drug therapy , Esophageal Neoplasms/radiotherapy , Aged , Aged, 80 and over , Combined Modality Therapy , Female , Humans , Male , Radiation Dosage , Radiotherapy/adverse effects , Retrospective StudiesABSTRACT
BACKGROUND: Nuclear fluorescence in keratinocytes is an occasional phenomenon, often present in autoimmune diseases, especially in connective-tissue disease (CTD); however, its clinical significance remains unclear. AIM: To investigate the profile of patients with positive nuclear staining on direct immunofluorescence (DIF) of skin samples. METHODS: A retrospective analysis of 28 patient records from our immunodermatology laboratory was performed between May 2003 and June 2006. Inclusion criteria were the presence of autoantibodies (IgG, IgA or IgM) or complement (C3) binding keratinocyte nuclei on DIF. RESULTS: The most prevalent diseases related to the nuclear keratinocyte DIF staining were systemic lupus erythematosus (n = 9), mixed CTD (n = 3), overlap syndrome (n = 3), Sjögren's syndrome (n = 1), and CREST (calcinosis, Raynaud's phenomenon, oesophageal dysmotility, sclerodactyly and telangiectasia) syndrome (n = 1). Serum antinuclear antibody (ANA) was positive in 20 of 28 patients, with titres varying from 1 : 160 to 1 : 1280. Of the 20 patients with positive anti-nuclear antibodies (ANA), 17 were positive for anti-extractable nuclear antigen antibodies, 12 had anti-SSA/Ro, 11 had anti-SSB/La and 8 had anti-ribonucleoprotein. Eight patients were negative for ANA. Positive predictive value of in vivo ANA for systemic CTDs was 75%. CONCLUSION: The present data suggest that in vivo ANA evaluation is an additional and feasible auxiliary tool for diagnosing CTDs.
Subject(s)
Antibodies, Antinuclear/analysis , Connective Tissue Diseases/diagnosis , Epidermis/immunology , Adolescent , Adult , Aged , Biomarkers/analysis , Cell Nucleus/immunology , Connective Tissue Diseases/immunology , Feasibility Studies , Female , Fluorescent Antibody Technique, Direct/methods , Humans , Keratinocytes/immunology , Male , Middle Aged , Retrospective Studies , Young AdultABSTRACT
SHP-2 protein tyrosine phosphatase plays an important role in activation of the RAS-dependent signaling. Gain-of-function mutations in the PTPN11 gene, which encodes SHP-2, have been found in the leukemia-prone developmental disorder Noonan syndrome as well as sporadic childhood leukemias, indicating that SHP-2 is a bona fide human oncoprotein. However, the role of SHP-2 mutations in non-hematological malignancies remains obscure. Here, we screened for PTPN11 mutations in primary solid tumors and identified a 1520C>A mutation that causes threonine-507 to lysine (T507K) substitution in the phosphatase domain of SHP-2 in a case of hepatocellular carcinoma. T507K SHP-2 exhibited altered substrate specificity with slightly elevated basal phosphatase activity. Upon expression in NIH3T3 cells, T507K SHP-2 induced transformed foci, which was not observed with wild type, Noonan-specific or leukemia-specific SHP-2. Furthermore, NIH3T3 cells transformed by T507K SHP-2 showed anchorage-independent growth and developed tumors in nude mice. These results indicate that quantitative and/or qualitative alteration in phosphatase activity determines the transforming potential as well as target cell/tissue spectrum of individual SHP-2 mutants as oncoproteins. Although rare in solid tumors, the identified T507K SHP-2 represents a distinct class of SHP-2 mutants with oncogenic RAS-like transforming activity, which could contribute to the development of solid tumors.
Subject(s)
Cell Transformation, Neoplastic , Liver Neoplasms/genetics , Liver Neoplasms/metabolism , Mutation , Protein Tyrosine Phosphatase, Non-Receptor Type 11/genetics , Protein Tyrosine Phosphatase, Non-Receptor Type 11/metabolism , ras Proteins/metabolism , Aged , Aged, 80 and over , Animals , Carcinoma, Hepatocellular/pathology , Cell Line, Tumor , Female , Humans , Male , Mice , Mice, Nude , Middle Aged , NIH 3T3 CellsABSTRACT
BACKGROUND AND STUDY AIM: Fistula occlusion is not achieved in some fistulas with complex branches. To obtain early fistula closure in such cases, we insert a double-lumen catheter into each fistula branch, with the aid of a guide wire positioned using a small-caliber endoscope, and attempt selective infusion of fibrin glue. PATIENTS AND METHODS: Following removal of foreign bodies and necrotic granulation, we applied the selective occlusion method under fistuloscopic control to seven intractable external fistulas with complex branches, in which fistula closure had not been obtained by a simple occlusion method (SOM). All the fistulas were complex with more than two branches. RESULTS: Fistula occlusion was obtained within 2 weeks in six of the seven patients, and there has been no sign of recurrence over a follow-up period of 4 - 59 months (average 29.8 months). CONCLUSION: Selective occlusion under fistuloscopy is highly effective for intractable external fistulas with complex branches.
Subject(s)
Endoscopy, Gastrointestinal , Fibrin Tissue Adhesive/administration & dosage , Fistula/therapy , Postoperative Complications/therapy , Tissue Adhesives/administration & dosage , Digestive System Surgical Procedures , HumansABSTRACT
From the aquatic bacterium Rhodococcus equi strain S(420), we isolated a substance that strongly binds to influenza viruses. Structural analyses revealed that it is a unique type of phosphatidylinositol (PtdIns) bearing a branched-chain fatty acid (14-methyloctadecanoic acid). In a TLC/virus-binding immunostaining assay, this PtdIns bound to all subtypes of hemagglutinin (HA) of influenza A viruses tested, isolated from humans, ducks and swine, and also to human influenza B viruses. Furthermore, the PtdIns significantly prevented the infection of MDCK cells by influenza viruses, and also inhibited the virus-mediated hemagglutination and low pH-induced hemolysis of human erythrocytes, which represents the fusogenic activities of the viral HA. We also used purified hemagglutinin instead of virions to examine the interaction between viral HA and PtdIns, showing that the PtdIns binds to hemagglutinin. These findings indicate that the inhibitory mechanism of PtdIns on the influenza virus infection may be through its binding to viral HA spikes and host cell endosomal/lysosomal membranes, which are mediated by the function of viral HA.
Subject(s)
Hemagglutinins, Viral/metabolism , Influenza A virus/metabolism , Influenza, Human/prevention & control , Phosphatidylinositols/metabolism , Phosphatidylinositols/pharmacology , Rhodococcus equi , Animals , Binding Sites/physiology , Cells, Cultured , Dogs , Ducks , Fatty Acids/chemistry , Hemagglutination/drug effects , Hemolysis/drug effects , Humans , Influenza B virus/chemistry , Kidney/cytology , Orthomyxoviridae/metabolism , Phosphatidylinositols/isolation & purification , SwineABSTRACT
The majority of influenza A viruses isolated from wild birds, but not humans, can replicate in the duck intestinal tract. Here we demonstrate that all duck isolates tested universally retain sialidase activities under low pH conditions independent of their neuraminidase (NA) subtypes. In contrast, the sialidase activities of most isolates from humans and pigs practically disappear below pH 4.5, with the exception of four human pandemic viruses isolated in 1957 and 1968. Sequence comparisons among duck, human, and swine N2 NA subtypes indicate that amino acids at positions 153, 253, 307, 329, 344, 347, 356, 368, 390, and 431 may be associated with the low pH stability of duck and human pandemic N2 NAs. This finding suggests that the low pH stability of duck influenza A virus NA may be a critical factor for replication in the intestinal tract through the digestive tract of ducks, and that the properties of NAs are important for understanding the epidemiology of the influenza virus.
Subject(s)
Influenza A virus/enzymology , Influenza, Human/virology , Neuraminidase/metabolism , Animals , Ducks , Enzyme Stability , Humans , Hydrogen-Ion Concentration , Influenza A virus/physiology , Influenza, Human/transmission , Phylogeny , Sequence Analysis , SwineABSTRACT
Using the cholera toxin B subunit (CTB) that specifically binds to ganglioside GM1a on the plasma membrane, we investigated intracellular signaling mediated by endogenous GM1a involved in neuronal differentiation of PC12 cells. The treatment with CTB induced morphological alternations of PC12 cells, such as augmentation of the cell body, neurite extension, and branched spikes of tips of neurites. The neurite extension induced with CTB was strongly suppressed by the pretreatment of tyrosine kinase inhibitors in a dose-dependent manner. Western blotting analysis showed that CTB induced tyrosine phosphorylation of several cellular proteins with molecular masses around 120, 70, and 45-40 kDa in PC12 cells. Some of the proteins identified were extracellular-signal regulated kinase (ERKs) (ERK1 and ERK2). The peak activation of ERKs lasted for 60-90 min and gradually decreased thereafter. Immunoprecipitation analysis demonstrated that the intracellular events induced with CTB are not related with the activation of Trk proteins, suggesting that signals evoked by ligation of endogenous GM1a are unique and distinct from those induced with exogenous GM1a. Although the presence of a tyrosine kinase inhibitor, genistein, at a concentration of 10 microM diminished the neurite extension of PC12 cells induced with CTB, ERK activation was still observed. However, pretreatment with a MEK inhibitor, PD98059, abolished the activation of ERKs induced with CTB in a dose-dependent manner and only attenuated the morphological alternations of PC12 cells. Considered together, we concluded that tyrosine phosphorylation induced with CTB was responsible for neuron-like differentiation of PC12 cells and that the MEK-ERK cascade is part of the biological signals mediated by endogenous ganglioside GM1a on PC12 cells.
Subject(s)
Cell Differentiation , G(M1) Ganglioside/metabolism , Neurons/cytology , Neurons/metabolism , Phosphotyrosine/metabolism , Receptor, trkA/metabolism , Animals , Blotting, Western , Cell Differentiation/drug effects , Cell Size/drug effects , Cholera Toxin/metabolism , Cholera Toxin/pharmacology , Chromatography, Thin Layer , Enzyme Activation/drug effects , Flavonoids/pharmacology , Genistein/pharmacology , MAP Kinase Signaling System/drug effects , Membrane Glycoproteins/metabolism , Microscopy, Fluorescence , Mitogen-Activated Protein Kinases/metabolism , Molecular Weight , Neurites/drug effects , Neurons/drug effects , PC12 Cells , Phosphorylation/drug effects , Precipitin Tests , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/metabolism , Rats , Receptor, trkA/antagonists & inhibitorsABSTRACT
Eleven novel analogs of 2-deoxy-2,3-didehydro-N-acetylneuraminic acid (Neu5Ac2en) modified at the C-4 and C-9 positions were designed and tested for their ability to inhibit sialidase of human parainfluenza virus type 1 (hPIV-1). The analogs modified by the cyanomethyl, amidinomethyl, and thiocarbamoylmethyl groups at the C-4 position exhibited potent inhibition against hPIV-1 sialidase compared with Neu5Ac2en. The most effective compound was thiocarbamoylmethyl analog (4-O-thiocarbamoylmethyl-Neu5Ac2en). The activity of 4-O-thiocarbamoylmethyl-Neu5Ac2en causing 50% enzyme inhibition at a concentration of approximately 1.0x10(-5) M was 30-fold larger than Neu5Ac2en. While, the analogs of Neu5Ac2en modified by the azido and N-acetyl groups at the C-9 showed a decrease in inhibition of sialidase compared with the 9-hydroxy analogs. In addition, 4-O-thiocarbamoylmethyl-Neu5Ac2en strongly inhibited hPIV-1 infections of Lewis lung carcinoma-monkey kidney cells in comparison with Neu5Ac2en. The present findings would provide useful information for the development of anti-human parainfluenza virus compounds.
Subject(s)
Antiviral Agents/chemistry , Antiviral Agents/pharmacology , N-Acetylneuraminic Acid/chemistry , N-Acetylneuraminic Acid/pharmacology , Neuraminidase/antagonists & inhibitors , Parainfluenza Virus 1, Human/enzymology , Animals , Haplorhini , Humans , Kinetics , Magnetic Resonance Spectroscopy , N-Acetylneuraminic Acid/analogs & derivatives , Neuraminidase/metabolism , Parainfluenza Virus 1, Human/drug effects , Parainfluenza Virus 1, Human/physiology , Structure-Activity Relationship , Tumor Cells, CulturedABSTRACT
BACKGROUND: Understanding the molecular mechanisms of complex cellular processes requires unbiased means to identify and to alter conditionally gene products that function in a pathway of interest. Although random mutagenesis and screening (forward genetics) provide a useful means to this end, the complexity of the genome, long generation time and redundancy of gene function have limited their use with mammalian systems. We sought to develop an analogous process using small molecules to modulate conditionally the function of proteins. We hoped to identify simultaneously small molecules that may serve as leads for the development of therapeutically useful agents. RESULTS: We report the results of a high-throughput, phenotype-based screen for identifying cell-permeable small molecules that affect mitosis of mammalian cells. The predominant class of compounds that emerged directly alters the stability of microtubules in the mitotic spindle. Although many of these compounds show the colchicine-like property of destabilizing microtubules, one member shows the taxol-like property of stabilizing microtubules. Another class of compounds alters chromosome segregation by novel mechanisms that do not involve direct interactions with microtubules. CONCLUSIONS: The identification of structurally diverse small molecules that affect the mammalian mitotic machinery from a large library of synthetic compounds illustrates the use of chemical genetics in dissecting an essential cellular pathway. This screen identified five compounds that affect mitosis without directly targeting microtubules. Understanding the mechanism of action of these compounds, along with future screening efforts, promises to help elucidate the molecular mechanisms involved in chromosome segregation during mitosis.