Health Related Quality of Life in Patients with Pulmonary Tuberculosis

Tuberculosis (TB) is one of the major public health issues in many developing nations especially in Bangladesh. Though most focus is being directed towards mortality and incidence rate, the changes in morbidity and other health status parameters are not been well considered. The aim of the study was a comprehensive assessment of patients with pulmonary tuberculosis by measuring patient's quality of life which may lead to better outcome in patients' health, infection surveillance and prevention programs. This prospective study was conducted in the department of Respiratory and Internal Medicine, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from September 2015 to March 2017. The quality of life scores of 61 smear positive pulmonary tuberculosis cases were measured by validated Bangla version of SF-36 questionnaire before or at the starting of treatment, after the initial phase and at the end of treatment. Then the score was compared with those of 75 healthy matched controls. The changes of the quality of life with the stage of treatment and with socio-demographic variables were assessed. Before treatment, all domains of HRQoL of the pulmonary TB patients were significantly lower than those of the control group (p<0.001). At the end of six-month treatment period, HRQoL of the pulmonary TB patient had significantly increased compared to before treatment (p<0.001). There was no significant difference of scores after six months of treatment with that of control (p>0.05). The lowest score in tuberculosis patients was related to general health perception and vitality. Patients with low socio economic status, low educational level, prolonged disease duration and increased number of symptoms had lower HRQoL scores.

Etiological Evaluation of Patients with Lymphadenopathy by Clinical, Histopathological and Microbiological Assessment

Lymph node enlargement is a common presenting complaint in outpatient and inpatient department. The present observational cross sectional study was conducted in department of Internal Medicine, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh during the period from December 2014 to May 2016 to evaluate etiologies of significant lymphadenopathy by clinical, histopathological and microbiological assessment. Biopsy/FNA materials of 177 patients of 18-75 years age range with significant lymphadenopathy were sent for histopathology/cytology, Gram stain & culture, AFB stain & culture and Gene Xpert. Among them, 102(57.62%) were granulomatous lymphadenitis, 52(29.38%) were lymphoma, 12(6.78%) reactive lymphadenitis, 7(3.95%) metastatic malignancy, 2(1.13%) atypical lymphoid hyperplasia, 1(0.57%) myeloid sarcoma and 1(0.57%) chronic sialadenitis. Growth of MTB was on 23(22.55%) cases; among 102 granulomatous lymphadenitis and Gene Xpert was positive in 73(71.56%) cases with 100% Rif. sensitive. Gene Xpert is an important tool for diagnosis of tuberculous lymphadenitis. Time of symptoms to diagnosis of most of the TBL patients was within 2-8 months.

Serum Zinc Concentrations in Patients with Pulmonary Tuberculosis

Bangladesh is a tuberculosis (TB) burden country. It is one of the most important causes of mortality and morbidity and a major barrier of social and economic development. Zinc is a major trace element and an essential component of the body immune system. It's an important determinant of resistance to infection by maintaining cell mediated immunity. This analytical case control study was conducted in the Department of Internal Medicine, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh to see the association of serum zinc concentrations with pulmonary tuberculosis (PTB) in adult population (18-60 years) from January 2015 to January 2016. Freshly diagnosed PTB patients before initiating anti-TB chemotherapy as cases (N=43) and TB negative subjects as controls (N=48) were included conveniently in this study with a rigid selection criteria. Serum zinc concentrations were estimated by using atomic absorption spectrophotometer. The mean±SD age and BMI of the case group and control group were 33.30±14.71 and 32.69±11.60 years, 19.88±2.31 and 22.08±2.80 kg/m2 respectively. The concentrations of serum zinc were significantly lower (P=0.01) in PTB group (840.9±230.0 μgm/l) compared with the control group (965.6±219.9 μgm/l). There was marked variation of mean±SD serum zinc concentrations between male (1008.95±246.16 μgm/l) and female (937.24±200.35 μgm/l) in control group (P=0.182) though the variation is minimal in PTB group (P=0.724). The serum zinc concentrations showed positive correlation with BMI (P=0.642) but negative correlation with age (P=0.023) in both case and control. The lower serum zinc concentrations (12.06%) in PTB patients indicate relative immune deficiency. Routine assessment of serum zinc concentration of PTB patients should be considered and further outcome should be assessed with zinc supplementation.

Inducing pluripotency in vitro: recent advances and highlights in induced pluripotent stem cells generation and pluripotency reprogramming

Induced pluripotent stem cells (iPSCs) are considered patient-specific counterparts of embryonic stem cells as they originate from somatic cells after forced expression of pluripotency reprogramming factors Oct4, Sox2, Klf4 and c-Myc. iPSCs offer unprecedented opportunity for personalized cell therapies in regenerative medicine. In recent years, iPSC technology has undergone substantial improvement to overcome slow and inefficient reprogramming protocols, and to ensure clinical-grade iPSCs and their functional derivatives. Recent developments in iPSC technology include better reprogramming methods employing novel delivery systems such as non-integrating viral and non-viral vectors, and characterization of alternative reprogramming factors. Concurrently, small chemical molecules (inhibitors of specific signalling or epigenetic regulators) have become crucial to iPSC reprogramming; they have the ability to replace putative reprogramming factors and boost reprogramming processes. Moreover, common dietary supplements, such as vitamin C and antioxidants, when introduced into reprogramming media, have been found to improve genomic and epigenomic profiles of iPSCs. In this article, we review the most recent advances in the iPSC field and potent application of iPSCs, in terms of cell therapy and tissue engineering.

Chronic calcific pancreatitis and pancreatic cancer

An observational cross-sectional study of 50 cases of chronic calcific pancreatitis patients was conducted in Bangabandhu Sheikh Mujib Medical University (BSMMU) and some other tertiary level hospitals of Dhaka city from August 2008 to July 2010. Patients required laparotomy for different modalities of surgical treatment to manage chronic calcific pancreatitis were included in the study. Biopsy was taken from panceatic duct containing stone during laparotomy to determine the histopathological changes. Among 50 cases female predominance was observed. Male, female ratio was 2:3. Majority (62%) patients were in 20 to 40 years age group. Female presented earlier than male (20-30 years and 30-40 years respectively). All patients complained recurrent attack of epigastric pain. Other presentations were diabetes (74%), malnutrition and weight loss (56%), steatorrhoea (24%) and jaundice (12%). Adenocarcinoma was found in 3(6%) patients (2 male and 1 female) and rests were chronic pancreatitis. Several studies showed the association between chronic calcific pancreatitis and pancreatic cancer. Further large scale study is required to find out the national incidence level.

Induction of lysosomal and plasma membrane-bound sialidases in human T-cells via T-cell receptor

Among the three isoenzymes of neuraminidase (Neu) or sialidase, Neu-1 has been suggested to be induced by cell activation and to be involved in IL (interleukin)-4 biosynthesis in murine T-cells. In the present study, we found that antigen-induced airway eosinophilia, a typical response dependent on Th2 (T-helper cell type 2) cytokines, as well as mRNA expression of Th2 cytokines, including IL-4, are suppressed in Neu-1-deficient mice, thereby demonstrating the in vivo role of murine Neu-1 in regulation of Th2 cytokines. To elucidate the roles of various sialidases in human T-cell activation, we investigated their tissue distribution, gene induction and function. Neu-1 is the predominant isoenzyme at the mRNA level in most tissues and cells in both mice and humans, including T-cells. T-cells also have significant levels of Neu-3 mRNAs, albeit much lower than those of Neu-1, whereas the levels of Neu-2 mRNAs are minimal. In human T-cells, both Neu-1 and Neu-3 mRNAs are significantly induced by T-cell-receptor stimulation, as is sialidase activity against 4-methylumbelliferyl- N -acetylneuramic acid (a substrate for both Neu-1 and Neu-3) and the ganglioside G(D1a) [NeuAcalpha2-3Galbeta1-3GalNAcbeta1-4(NeuAcalpha2-3)Galbeta1-4Glcbeta1-cer] (a substrate for Neu-3, but not for Neu-1). The expression of the two sialidase genes may be under differential regulation. Western blot analysis and enzymic comparison with recombinant sialidases have revealed that Neu-3 is induced as a major isoform in activated cells. The induction of Neu-1 and Neu-3 in T-cells is unique. In human monocytes and neutrophils stimulated with various agents, the only observation of sialidase induction has been by IL-1 in neutrophils. Functionally, a major difference has been observed in Jurkat T-cell lines over-expressing Neu-1- and Neu-3. Upon T-cell receptor stimulation, IL-2, interferon-gamma, IL-4 and IL-13 are induced in the Neu-1 line, whereas in the Neu-3 line the same cytokines are induced, with the exception of IL-4. Taken together, these results suggest an important immunoregulatory role for both Neu-1 and Neu-3 in humans.

Differential inhibitor sensitivity between human recombinant and native photoreceptor cGMP-phosphodiesterases (PDE6s)

Human photoreceptor cGMP-phosphodiesterases (PDE6s) are important reagents in PDE inhibitor discovery. However, recombinant human PDE6s have not been expressed, and isolation of native human PDE6s is highly difficult. In this study, the catalytic subunit(s) of human rod and cone PDE6s (PDE6alphabeta and PDE6alpha', respectively) were co-expressed or expressed separately as catalytically active enzymes. Sildenafil inhibited both the recombinant PDE6s in a dose-dependent manner with Ki values of 94 and 98 nM, respectively. These Ki values were four-fold higher than that (25 nM) of a human native PDE6 preparation. Similarly, 3-isobutyl-1-methylxanthine (IBMX)'s Ki values for the recombinant PDE6s were five- to eight-fold higher than that of the native enzyme. However, E4021 and zaprinast exhibited much (30-80-fold) lower potencies for the recombinant PDE6s than for the native enzyme. Additional PDE5 inhibitors representing other structural classes and possessing different selectivity against native PDE6 also showed different potencies against the recombinant and native PDE6s. In particular, one class of xanthine analogues exhibited significantly (5-15-fold) higher potencies for the recombinant PDE6s than for the native enzyme. Our data demonstrates that the recombinant and native PDE6s exhibit differential sensitivity to inhibitors, and cautions the use of recombinant catalytic subunits of PDE6 in drug discovery or in structural/functional studies.

The role of neutrophils in LPS-induced changes in pulmonary function in conscious rats

We have previously reported on a model of lipopolysaccharide (LPS)-induced pulmonary inflammation in rats, where LPS-challenged animals develop a significant pulmonary neutrophilia and mucus hypersecretion. In the current studies, we utilized whole body plethysmography and computer assisted data acquisition to examine changes in pulmonary parameters, e.g. frequency (f) tidal volume and Penh as a measure of bronchoconstriction, due to LPS-challenge in conscious rats. Compared to saline challenge, LPS-challenged rats displayed a significant increase in (f) which began within 30 min, peaked by 2 h and remained elevated up to 24 h. Mirroring this increase in (f) was a decrease in the observed tidal volume of LPS-challenged rats. Additionally, compared to saline challenge, LPS-challenge provoked a significant and spontaneous bronchoconstriction, as measured by Penh, 2 h after challenge. In order to further understand these observed LPS-induced pulmonary changes, we utilized two classes of pulmonary obstructive disease standards, namely, bronchodilators and anti-inflammatory agents, and examined their ability to affect the spontaneous bronchoconstriction and the increase in (f) seen at two discrete time points, i.e. 2 and 24 h after LPS-challenge. While ineffective on either the 2 h increase in (f) or the LPS-induced inflammation, animals pretreated with salbutamol (10 mg/kg, p.o.) were protected from the increase in (f) seen at the 24 h time point after LPS-challenge. In contrast, when animals were pretreated with theophylline (10 mg/kg, p.o.) no effect on the LPS-induced pulmonary inflammation or increase in (f) was noted. Meanwhile, in animals pretreated with either betamethasone (3 mg/kg, p.o.) or SB207499 (10 mg/kg, p.o.), a PDE4 inhibitor, doses previously shown to block the LPS-induced neutrophilic inflammation, the persistent increase in (f) seen at 24 h was attenuated, but neither compound was able to attenuate either the increase in (f) or the spontaneous bronchoconstriction seen at 2 h. In summary, the intra-tracheal LPS-challenge of rats results in pulmonary inflammation and dysfunction, which is similar to that seen in COPD patients. We conclude that the early increase in (f) and bronchoconstriction are not dependent upon airway inflammation, but airway inflammation most likely contributes to the persistent increase in (f) seen at 24 h.

Identification and characterization of a new human type 9 cGMP-specific phosphodiesterase splice variant (PDE9A5). Differential tissue distribution and subcellular localization of PDE9A variants

Previously, four splice variants of human cGMP-specific phosphodiesterase (PDE) 9A (PDEs 9A1, 9A2, 9A3 and 9A4) have been identified. In this study, we have cloned a cDNA representing a new human PDE9A variant (PDE9A5). PDE9A5 encodes a protein of 492 amino acids, smaller than PDEs 9A1 and 9A2 but larger than PDEs 9A3 and 9A4. The exon structure of PDE9A5 is different from those of PDEs 9A1, 9A2, 9A3 and 9A4 in that, of the 20 exons of PDE9A gene, it lacks exons 2 and 5. PDE9A5 has been characterized in comparison with PDE9A1, the longest PDE9A variant. PDEs 9A5 and 9A1 have similar enzymatic properties. They both have a high affinity for cGMP with similar Km values (0.39 and 0.25 microM, respectively), although they have slightly different Vmax values (2.55 and 0.96 micromol/min/mg, respectively). They exhibit very similar divalent metal ion dependency and inhibitor sensitivity. Real-time quantitative PCR analysis shows that PDEs 9A5 and 9A1 exhibit differential tissue distribution. They are highly expressed in immune tissues (spleen, lymph node and thymus) and are more abundant in T cells than in B cells, neutrophils and monocytes. When transiently expressed in HEK293 cells, PDEs 9A5 and 9A1 proteins exhibit differential subcellular localization. PDE9A5 localizes exclusively in the cytoplasm, whereas PDE9A1 localizes in the nucleus only. The nuclear localization of PDE9A1 is dependent on a unique pat7 motif. By Western blot analysis, native PDE9A1 is detectable in the nucleus but not in the cytoplasm of T cells. Thus, to our knowledge, PDE9A1 is the only PDE isoform found to localize exclusively in the nucleus. We speculate that the physiological role of the PDE9A diversity may be imparting cGMP-metabolizing ability to specific cellular compartments in appropriate tissues.

Human ADAM33: protein maturation and localization

ADAM33 (a disintegrin and metalloprotease) was recently found to be a novel asthma susceptibility gene. Domain-specific antibodies were used to study its expression and processing. When the pro-domain and catalytic domain were expressed by a stable-transfected cell line, the pro-domain was removed by cleavage within a putative furin cleavage site. The catalytic domain was active in an alpha(2)-macroglobulin complex formation assay and mutation of the catalytic site glutamic acid (E346A) eliminated activity. In transient transfections using the full-length protein, a pro-form and mature form were detectable and alternate glycosylation was demonstrated at sites within the catalytic domain. ADAM33 was detected on the cell surface, with the majority of protein detected intracellularly. The E346A mutation had no significant effect on protein processing. Endogenous ADAM33 was detected in bronchus tissue, bronchial smooth muscle cells, and MRC-5 fibroblasts, consistent with a role in the pathophysiology of asthma.

Identification of full, partial and inverse CC chemokine receptor 3 agonists using [35S]GTPgammaS binding

Study of the CC chemokine receptor 3 (CCR3) has been limited to using radiolabeled agonist chemokines. A small molecule CCR3 antagonist, 2-[(6-amino-2-benzothiazolyl)thio]-N-[1-[(3,4-dichlorylphenyl)methyl]-4-piperidinyl]acetamide, Banyu (I), was tritiated and used for pharmacological studies. Banyu (I) has a K(d) of 5.0+/-0.4 and 4.3+/-1.8 nM on human CCR3 transfectants and eosinophils, and noncompetitively inhibits [125I]eotaxin binding and eotaxin-induced [35S]guanosine-5'-O-(3-thiotriphosphate) ([35S]GTPgammaS) binding. The proportion of [125I]eotaxin: [3H]Banyu (I) binding sites in eosinophils or transfectants was 35% or 13%, although both binding sites were overexpressed in transfectants. CCR3 spontaneously couples to G-proteins in CCR3 transfectants, demonstrated by changes in basal and eotaxin-induced [35S]GTPgammaS binding under reduced NaCl and GDP concentrations. Consequently, Banyu (I) was identified as an inverse agonist. In contrast, CCL18 and I-TAC (interferon-inducible T cell alpha-chemoattractant) were neutral antagonists, inhibiting eotaxin-induced [35S]GTPgammaS binding, with minimal effect on basal coupling of CCR3 to G proteins. Eotaxin, eotaxin-2 and monocyte chemoattractant protein (MCP)-4 are full agonists inducing [35S]GTPgammaS binding; eotaxin-3, MCP-3, RANTES (regulated on activation normal T cell expressed and secreted), vMIP-I (Kaposi's sarcoma-associated herpesvirus macrophage inflammatory protein-) and vMIP-II are partial agonists, indicating that this is a sensitive method to quantitate agonist efficacy.

Pharmacology of N-(3,5-dichloro-1-oxido-4-pyridinyl)-8-methoxy-2-(trifluoromethyl)-5-quinoline carboxamide (SCH 351591), a novel, orally active phosphodiesterase 4 inhibitor

N-(3,5-Dichloro-1-oxido-4-pyridinyl)-8-methoxy-2-(trifluoromethyl)-5-quinoline carboxamide (SCH 351591) has been identified as a potent (IC(50) = 58 nM) and highly selective type 4 phosphodiesterase (PDE4) inhibitor with oral bioactivity in several animal models of lung inflammation. N-(3,5-Dichloro-4-pyridinyl)-8-methoxy-2-(trifluoromethyl)-5-quinoline carboxamide (SCH 365351), the only significant in vivo metabolite, is also a potent and highly selective PDE4 inhibitor (IC(50) = 20 nM). Both SCH 351591 and SCH 365351 inhibited cytokine production in human blood mononuclear cell preparations. Oral SCH 351591 significantly attenuated allergen-induced eosinophilia and airway hyperreactivity in allergic guinea pigs at doses as low as 1 mg/kg. In this model, oral SCH 365351 showed similar potency. When SCH 351591 was administered orally to allergic cynomolgus monkeys at 3 mg/kg, Ascaris suum-induced lung eosinophilia was blocked. Hyperventilation-induced bronchospasm in nonallergic guinea pigs, a model for exercise-induced asthma, was also suppressed significantly by oral SCH 351591 at 0.3 mg/kg. Cilomilast (SB 207499; Ariflo), a PDE4 inhibitor currently being developed for asthma and chronic obstructive pulmonary disease (COPD), was 10- to 30-fold less potent than SCH 351591 at inhibiting guinea pig lung eosinophilia and hyperventilation-induced bronchospasm. In a ferret model of emesis, maximum nonemetic oral doses of SCH 351591 and cilomilast were 5 and 1 mg/kg, respectively. Comparison of plasma levels at these nonemetic doses in ferrets to those at doses inhibiting hyperventilation-induced bronchospasm in guinea pigs gave a therapeutic ratio of 16 for SCH 351591 and 4 for cilomilast. Thus, SCH 351591 exhibits a promising preclinical profile as a treatment for asthma and COPD.

Human phosphodiesterase 8A splice variants: cloning, gene organization, and tissue distribution

We have cloned cDNAs representing five full-length human phosphodiesterase (PDE) 8A splice variants (PDE8As 1-5) from testis and T cells. PDE8A1 encodes a hydrophilic protein of 829 amino acids, containing an N-terminal REC domain, a PAS domain, and a C-terminal catalytic domain. PDE8A2 encodes a protein of 783 amino acids, identical to PDE8A1 but lacking the PAS domain. PDE8A3 encodes a shorter protein equivalent to the C-terminal 449 amino acids of PDE8A1, containing the catalytic but not the REC and PAS domains. PDE8A4 and PDE8A5, though different from each other at the nucleotide level, encode an identical protein equivalent to the C-terminal 582 amino acids of PDE8A1, including half of the PAS domain. The PDE8A gene is revealed to contain 23 exons, and its exon-intron boundaries have been defined. In addition, we have mapped a common transcription initiation site, and further determined the upstream 5'-flanking sequence of 1740 bp containing the putative promoter. Compared to PDE8A1, PDE8As 2-5 appear to be expressed in much lower abundance. Among various tissues and organs, PDE8A1 and PDE8A2 are expressed at various levels.

Characterization of human, dog and rabbit corpus cavernosum type 5 phosphodiesterases

Human, dog and rabbit corpus cavernosum type 5 phosphodiesterases (PDE5) were isolated and their characteristics were compared. The three enzymes showed Km values of 0.8, 2.1 and 2.3 uM, respectively. They exhibited similar pH-dependence with optimal pH being 7.5. They required Mg++ for activity and the activity was suppressed by high concentrations of Zn++ (0.1-1 mM). Sildenafil potently inhibited the three enzymes with IC50 values of 3.6, 1.7 and 3.0 nM, respectively. Dipyridamole and IBMX (3-isobutyl-1-methylxanthine) each also inhibited the three enzymes with similar, albeit lower, potencies (IC50 about 1.1 and 5.7 uM, respectively). However, zaprinast exhibited a significantly higher potency against the rabbit enzyme (IC50 53 nM) than against the human and dog PDE5s (IC5s 332 and 217 nM, respectively). Thus, the corpus cavernosum PDE5s are very similar among the various species with the only significant difference being their sensitivity to zaprinast. Human platelet PDE5 was also characterized by comparison with the corpus cavernosum enzyme. The platelet enzyme exhibited a Km, pH-, Mg++- and Zn++-dependence, and sensitivity to sildenafil and zaprinast very similar to those of the corpus cavernosum PDE5. However, compared with corpus cavernosum PDE5, the platelet enzyme exhibited higher sensitivity to dipyridamole and IBMX (IC50 0.46 and 1.8 uM, respectively). This study shows that despite similar kinetics and enzymatic properties, corpus cavernosum PDE5s from different species, and corpus cavernosum and platelet PDE5s, can have differential sensitivity to pharmacological inhibitors.

Cloning, characterization, and tissue distribution of mouse phosphodiesterase 7A1

We have cloned a cDNA representing mouse phosphodiesterases (PDE) 7A1. The open reading frame encodes a protein of 482 amino acids with a predicted molecular mass of 55417. Like human PDE7A variants, mouse PDE7A1 and A2 are 5' splice variants from a common gene. The distinct N-terminal sequence of mouse PDE7A1 is highly homologous to the corresponding sequence of human PDE7A1 with a similarity of 98% but not to that of mouse PDE7A2 (with a similarity of 12%), and is more hydrophilic than that of mouse PDE7A2. Mouse PDE7A1 expressed in SF9 cells has been compared with human PDE7A1 under identical conditions. Mouse PDE7A1 has a Km for cAMP of 0.2 microM, an optimal pH of 7.5, an IC(50) value of 14 microM for 3-isobutyl-1-methylxanthine (IBMX), and is dependent on Mg(2+) for activity. All these characteristics are very similar to those of human PDE7A1. In mice, PDE7A1 is expressed in tissues of the immune system (lymph node, thymus, spleen, and blood leukocyte), testis, brain, kidney and lung but not in skeletal muscle, heart, embryo, or liver, while PDE7A2 is expressed in skeletal muscle, heart, embryo, and kidney, but not in the other tissues. This tissue distribution profile is very similar to that in humans, and hence suggests that PDE7A1 and 7A2 might play a similar role in different species.

Receptor reserve analysis of the human CCR3 receptor in eosinophils and CCR3-transfected cells

A novel pharmacological study of CCR3 receptor reserve in a CCR3-transfected cell (CREM3) and human eosinophils was done; functional responses measured were increases in intracellular calcium and chemotaxis. Eotaxin, eotaxin-2, monocyte chemoattractant protein-4 (MCP-4), RANTES, and MCP-3 induced similar maximal eosinophil chemotaxis, whereas MCP-3 and RANTES induced submaximal calcium responses in eosinophils compared to eotaxin, MCP-4, and eotaxin-2. This suggested a receptor reserve in the chemotaxis response. Receptor reserve was quantitated for eotaxin. Occupancy of all CCR3 receptors was required for a maximal calcium response in both CREM3 and eosinophils (reserve = 1.0 or 0.17, respectively); the stimulus-calcium response relationship was linear, indicating no receptor reserve. In contrast, in eosinophils a large receptor reserve (6.5) was found for chemotaxis, where occupancy of 15% receptors drove half-maximal responses. These studies indicate that CCR3 interacts with G-proteins that are poorly coupled to the calcium response, whereas coupling efficiency and/or amplification to the chemotaxis apparatus in human eosinophils is significantly greater.

Mapping and characterization of the epitope(s) of Sch 55700, a humanized mAb, that inhibits human IL-5

mAb against human IL-5 inhibit pulmonary eosinophilia, tissue damage and airway hyper-reactivity in allergic animal models. Sch 55700 is a humanized, neutralizing anti-IL-5 antibody. To better understand the molecular mechanism by which Sch 55700 blocks IL-5 bioactivity, we have mapped its epitope by scanning IL-5 with synthetic peptides. Those peptides containing a region, ERRRV, corresponding to amino acids 89-93 of IL-5 specifically interact with both Sch 55700 and its parental rat IgG, 39D10. Among the five residues of this region, all three arginine residues were particularly critical for interaction of these peptides with Sch 55700. We further characterized this region by alanine scanning using site-directed mutagenesis. Examination of COS-expressed IL-5 mutants by Western blot showed that single mutations of E(89), R(90), R(91) or R(92) to alanine caused a loss of IL-5 binding to both Sch 55700 and 39D10. We further demonstrated in surface plasmon resonance studies using a BIAcore biosenosor that E(89), R(90) or R(91) are involved in the interaction between IL-5 and its receptor alpha subunit. Based upon the findings here and previously reported structures of the IL-5 and 39D10 variable region, we propose a model suggesting that the molecular interactions between the IL-5 and Sch 55700 mainly involve several ion pair interactions. We conclude that Sch 55700 occupies a region, ERRR, on IL-5 that is essential for its interaction with the receptor and thereby blocks IL-5 bioactivity.

The assignment of chemokine-chemokine receptor pairs: TARC and MIP-1 beta are not ligands for human CC-chemokine receptor 8

Identification of chemokine receptors and their associated ligands is crucial to the understanding of most immune reactions. Three human chemokines [I-309, thymus and activation-regulated chemokine (TARC) and macrophage inflammatory protein-1beta (MIP-1beta)] have been reported to be ligands for CC-chemokine receptor 8 (CCR8). In this report, we present evidence that TARC and MIP-1beta did not bind to or induce chemotaxis through CCR8 on a stable transfected cell line (1D-21) and did not bind to CCR8 on in vitro differentiated human CD4(+) Th(2) cell cultures. Also, I-309-dependent calcium mobilization in 1D-21 cells and in Th(2) cells was desensitized by I-309 but not by MIP-1beta or TARC. These results provide strong evidence that, at physiologically relevant concentrations, I-309 is the only known human ligand for CCR8. These data also provide a framework for suggesting minimum requirements for the assignment of chemokine receptor-ligand pairs.

The profiles of human and primate [3H]Nalpha-methylhistamine binding differ from that of rodents

Characterization of the histamine H3 receptor in rodent species has been extensive but limited characterization has been done with primate or human tissue. We have characterized the binding of [3H]Nalpha-methylhistamine to cynomolgus monkey and human brain membranes to determine whether there are any significant differences among species' pharmacology. In monkey, [3H]Nalpha-methylhistamine bound, in a guanine nucleotide-sensitive fashion, to an apparently homogeneous class of sites at equilibrium (K(D) = 1.4 nM, Bmax = 34 fmol/mg protein). The profile of binding was broadly similar to that of rodents, with a couple of significant differences. Most notably, the potency of the histamine H3-receptor-specific antagonist thioperamide (Ki = 240 nM) was substantially less than reported for rodents and under assay conditions that yield a two-site curve fit in rodents only a single class of thioperamide binding sites was detected in monkey. Burimamide, however, yielded a two-site curve fit (KiH = 6.7 nM, KiL = 1100 nM) independent of the presence of sodium in the assay, as it does in rodents. Characterization of the human brain histamine H3 receptor showed that it was similar to the monkey and not rodent receptor. Our findings indicate that differences between primate and rodent histamine H3 receptors of potentially serious importance for the discovery of antagonists active in humans do exist.

Conformational considerations in the design of dual antagonists of platelet-activating factor (PAF) and histamine

Following the discovery of the first dual antagonist of platelet-activating factor (PAF) and histamine, 1-acetyl-4-(8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin- 11-ylidene)piperidine, Sch 37370, 1, a related series of structures, exemplified by (+/-)-1-acetyl-4-(8-chloro-5,6-dihydro-11H-benzo[5,6]-cyclohepta[1,2-b] pyridin-11-yl)piperazine, Sch 40338, 2, were prepared. Interestingly, the compounds exhibited a parallel structure antiallergy activity relationship, suggesting that the two series may adopt a common conformation at the PAF receptor. Conformational analysis led to a proposal for this bioactive conformation accessible to both series. The synthesis of novel conformationally constrained analogues that might mimic the proposed bioactive conformation of these compounds, and the evaluation of their in vitro antiallergy activity form the subject matter of this report.

Phosphodiesterase 4B2 is the predominant phosphodiesterase species and undergoes differential regulation of gene expression in human monocytes and neutrophils

The type 4 phosphodiesterase (PDE4) is the predominant PDE isozyme in various leukocytes and plays a key role in the regulation of inflammatory cell activation. There are four PDE4 subtypes (A, B, C, and D), and within each subtype, there are multiple variants. Very recently, we found in monocytes that PDE4B gene expression is selectively induced by lipopolysaccharide (LPS) and that the induction is inhibited by interleukin (IL)-10 and IL-4. In this study, we show that the PDE4B gene is constitutively expressed in neutrophils and that this expression remains unaffected by LPS or IL-10. PDE4B is the predominant subtype in neutrophils and in unstimulated or LPS-stimulated monocytes, and in these cells, the PDE4B2 variant is the only detectable molecular species of PDE4B. Therefore, PDE4B2 is the predominant PDE isoform in human neutrophils and monocytes, and its expression is regulated differently by these two cell types. Furthermore, leukocytes are the most dominant source of PDE4B2, suggesting that PDE4B2 is a relatively specific target for discovering anti-inflammatory drugs.

Effects of cyclosporin A and dinactin on T-cell proliferation, interleukin-5 production, and murine pulmonary inflammation

We compared the effects of cyclosporin A (CSA) and a macrotetrolide antibiotic, dinactin, on human T-cell proliferation and cytokine production induced by stimulation of the T-cell receptor alone (monoclonal antibody [mAb] directed against CD3) or in combination with costimulatory signals (mAbs directed against CD3 and CD28). These agents were also examined in a murine model of interleukin (IL)-5-mediated pulmonary inflammation. Dinactin inhibited T-cell proliferation induced by IL-2, by mAb to CD3, and by mAbs to CD3 plus alpha-CD28 with identical dose-response curves (IC50 = 10-20 ng/ml). Dinactin inhibited cytokine production with IC50 values of 10 ng/ml for IL-4 and IL-5 and 30 or 60 ng/ml for interferon-gamma or IL-2, respectively. Unlike CSA, exogenous IL-2 did not alter the dinactin-mediated effects on T cells, and nuclear run-on and steady-state messenger RNA (mRNA) analysis showed that dinactin inhibited cytokine production through a post-transcriptional mechanism. CSA selectively blocked T-cell receptor-induced T-cell proliferation and cytokine production (IC50 = 10 ng/ml). Under costimulatory conditions, IL-5 synthesis was only minimally inhibited by high concentrations of CSA, and at CSA concentrations of less than 125 ng/ml, IL-5 was significantly increased above control values. Dinactin and CSA reduced pulmonary eosinophilia when administered within 1 d of airway antigen challenge. Of the cytokine mRNAs examined in the lungs of CSA-pretreated, antigen-challenged mice, IL-5 mRNA levels were the least reduced, paralleling the resistance of IL-5 to CSA observed in vitro and suggesting a role for CD28 in the in vivo induction of IL-5.

A scintillation proximity assay for human interleukin-5 (hIL-5) high-affinity binding in insect cells coexpressing hIL-5 receptor alpha and beta subunits

The high-affinity receptor for human interleukin-5 (hIL-5) is composed of alpha and beta subunits. A baculovirus expression system was established in Sf9 cells capable of expressing hIL-5 receptor alpha and beta subunits simultaneously. By using wheat germ agglutinin (WGA)-coated scintillation proximity assay (SPA) beads to capture 125I-labeled hIL-5-bound Sf9 cells, a SPA was developed and used to measure hIL-5 high-affinity binding. The hIL-5 receptors expressed in the Sf9 cells represented a single class of high-affinity binding sites with a dissociation constant (Kd) of 0. 24 nM and a density of 2.95 x 10(5) sites/cell. This is the first study in which the high-affinity Kd value similar to that for hIL-5 binding to human eosinophils was achieved using a recombinant expression system. The SPA compared favorably with the filter binding assay with regard to various binding parameters. We also found that several lectins, when coated on SPA beads, were even more effective than WGA-coated SPA beads for capturing the insect cells. We conclude that the baculovirus expression system was highly efficient in producing the high-affinity hIL-5 receptors and that the SPA was a simple and sensitive assay that could be readily adapted into a high-throughput screening format. The SPA described here could be a prototype for binding assays for other multimeric receptors.

Effects of chronic anti-interleukin-5 monoclonal antibody treatment in a murine model of pulmonary inflammation

The maturation of eosinophils in bone marrow, their migration to pulmonary tissue, and their subsequent degranulation and release of toxic granule proteins contributes to the pathophysiology observed in asthma. Interleukin-5 (IL-5) is essential for these processes to occur. Therefore, much emphasis has been placed on attempts to inhibit the production or activity of IL-5 in order to attenuate the inflammatory aspect of asthma. In this report, the immunological consequences of long-term exposure to an antibody recognizing IL-5 (TRFK-5) were studied in a murine pulmonary inflammation model. A single dose of TRFK-5 (1 mg/ kg, intraperitoneally) reversibly inhibited antigen-dependent lung eosinophilia in mice for at least 12 wk and inhibited the release of eosinophils from bone marrow for at least 8 wk. Normal responses to aerosol challenge were attained after 24 wk. In mice treated acutely with antibody (2 h before challenge), 50% inhibition of pulmonary eosinophilia occurred when 0. 06 mg/kg TRFK-5 was administered (intraperitoneally; ED50), resulting in 230 ng/ml (IC50) in serum. In mice treated with one dose of TRFK-5 (1 mg/kg) and rested before challenge, the antibody exhibited a half-life of 2.4 wk. After 18 to 19 wk, antigen challenge-induced eosinophilia was inhibited by 50% and serum levels of TRFK-5 were 25 ng/ml. TRFK-5 remaining in mice 8 wk after a single injection of TRFK-5 was sufficient to inhibit at least 50% of the eosinophilia induced in blood 3 h after injection of recombinant murine IL-5 (10 microg/kg, intravenously). To assess the biologic effect of long-term exposure of mice to antibody, several parameters of immune-cell function were measured. Throughout the extended period of activity of TRFK-5 (>/= 12 wk) there were no gross effects on antigen-dependent increases in T-cell recruitment into bronchoalveolar fluid (BALF), in IL-4 and IL-5 steady-state mRNA levels in lung tissue, or in immunoglobulin E (IgE) and IgG levels in serum. There was a small increase in IL-5 steady-state mRNA production in TRFK-5-treated mice after 2 h or 2 wk, but this was not observed at other times examined. In untreated mice, IL-5 steady-state mRNA production in response to antigen challenge decreased > 6-fold with age, although at all time points there was an increase in mRNA levels following challenge. Therefore, at later times, 25 ng/ml rather than 230 ng/ml of TRFK-5 inhibited BALF eosinophilia, probably because of reduced IL-5 levels. Twenty-four weeks after treatment with TRFK-5, when challenge-induced eosinophilia was restored, there was an excess of CD4(+) T cells in BALF from challenged mice. However, these T cells had no measurable effects on other responses to challenge, including cytokine production, B-cell accumulation, and immunoglobulin production in serum. Thus, the biologic duration of TRFK-5 was several months, and its activity was due to the presence of antibody above a therapeutic threshold rather than to any profound effect on the immune system.

Phosphodiesterase 4B gene transcription is activated by lipopolysaccharide and inhibited by interleukin-10 in human monocytes

There are four different genes encoding the cAMP-specific phosphodiesterase (PDE4) isozymes (A, B, C, and D). cAMP has been the only agent known to induce PDE4 gene expression. In the present study, we demonstrate, for the first time, that lipopolysaccharide (LPS) significantly and selectively stimulated PDE4B mRNA production in human monocytes. The LPS stimulation occurred very rapidly (in 30-45 min) and in a dose-dependent manner (0.01-100 ng/ml). We also demonstrate that LPS induction of PDE4B mRNA expression was inhibited strongly by interleukin (IL)-10. The inhibition with IL-10 was dose-dependent (0.1-10 ng/ml). IL-4 also inhibited the LPS induction, but to a lesser extent than IL-10. PDE4B mRNA expression was also stimulated by dibutyryl-cAMP. Interestingly, unlike LPS induction, the dibutyryl-cAMP induction of PDE4B mRNA expression was not inhibited by IL-10. By performing nuclear run-on and mRNA stability assays, we demonstrate further that IL-10 inhibited LPS-stimulated PDE4B mRNA synthesis by abolishing the gene transcription rather than by enhancing mRNA degradation. The present study suggests that PDE4B, as the only LPS-inducible PDE4 subtype, may be an appropriate target for discovering anti-inflammatory drugs.

Dual antagonists of platelet activating factor and histamine. 3. Synthesis, biological activity and conformational implications of substituted N-acyl-bis-arylcycloheptapiperazines

A series of N-acyl-4-(5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin- 11-ylidene)piperazines is described that are dual antagonists of PAF and histamine. The structural requirements for activity in this series parallel those of their previously reported piperidinylidene counterparts. Whereas their global minimum energy conformations are different for both series of compounds, computer assisted molecular modeling suggests that a common bioactive conformation is possible.

Characterization of the mouse interleukin-5 promoter in a mouse TH2 T cell clone

The proximal mouse IL-5 promoter was examined using a mouse TH2 clone stimulated through the T cell receptor using anti-CD3 monoclonal antibody. DNase I protection defined four protein binding regions [IL-5RE-A, -69/-45; -B, (-90/-76); -C, (-154/-130); and -D (-176/-157)]. Stimulation-dependent binding, which was seen in the IL-5RE-B, -D regions and the 5' end of tIL-5RE-A, did not require new protein synthesis inhibitor during cell activation. EMSA using probes targeted to the IL-5RE-B, -C, -D regions demonstrated the multimeric nature of the bound proteins. By transfection analysis using a series of truncated IL-5 promoter-luciferase constructs, IL-5RE-C and -D contributed little to constitutive or inducible activity. The CLE0 site in the IL-5RE-A region contributed to full transcriptional activity but was not sufficient to mediate full activity. Full stimulation-dependent activity required the IL-5RE-B region and/or the GATA site (-70/-60).

Interleukin-5 mRNA stability in human T cells is regulated differently than interleukin-2, interleukin-3, interleukin-4, granulocyte/macrophage colony-stimulating factor, and interferon-gamma

Interleukin-5 (IL-5) transcriptional activation and mRNA stability were investigated in a human TH0 T-cell clone (SP-B21) and in nonclonal CD4 TH2 cells, differentiated in vitro from peripheral blood T cells. Cells were stimulated with alpha-CD3 monoclonal antibody (mAb) with and without alpha-CD28 mAb. Comparison to other cytokine genes revealed aspects of mRNA regulation unique to IL-5. The half-life (t1/2) of IL-5 mRNA, determined by addition of actinomycin D (ActinoD) or cyclosporin A (CSA) was longer (by >= 2 h) than that of IL-2, IL-3, IL-4, interferon-gamma, or granulocyte/macrophage colony-stimulating factor. With the exception of IL-5, t1/2 values were significantly shorter with CSA as the transcriptional inhibitor than with ActinoD. The t1/2 value of IL-5 mRNA, but not the other cytokine transcripts, determined with either ActinoD or CSA, was longer than predicted from the kinetics of steady-state mRNA decline. Co-stimulation of both cell types with alpha-CD28 mAb increased the stability of cytokine transcripts weakly, and IL-5 remained the most stable transcript. Thus, the degradation pathway that targets IL-5 is distinct from the other cytokine transcripts measured and involves proteins whose transcription is blocked by ActinoD and CSA. From examination of the levels of transcription initiation (nuclear run-on assay) and steady-state mRNA attained in cultures stimulated in the presence of the protein synthesis inhibitor, cycloheximide, only IL-5 transcription initiation had an absolute dependency on new protein synthesis.

Selective Inhibition of IL-5 Receptor α-Chain Gene Transcription by IL-5, IL-3, and Granulocyte-Macrophage Colony-Stimulating Factor in Human Blood Eosinophils

High affinity receptor for IL-5 (IL-5R), a predominant eosinophil maturation factor, is composed of an IL-5-binding α-chain (IL-5Rα) and a signal-transducing β-chain that is shared by IL-3 and granulocyte-macrophage CSF (GM-CSF) receptors (IL-3R and GM-CSFR). By Northern blot analysis of mRNAs obtained from normal human blood eosinophils, we show in this report that the hematopoietic cytokines IL-5, IL-3, and GM-CSF down-regulate IL-5Rα mRNA while up-regulating α-chain mRNAs for both IL-3R and GM-CSFR as well as the β-chain mRNA. More detailed characterization reveals that the down-regulation of IL-5Rα mRNA is specific to IL-3, IL-5, and GM-CSF; occurs very rapidly (reaching maximum inhibition within 2 h); is cytokine dose dependent; and does not require protein synthesis. Nuclear run-on and mRNA stability experiments demonstrate that cytokine-induced inhibition of IL-5Rα mRNA accumulation occurs at the level of IL-5Rα gene transcription, whereas enhanced accumulation of mRNAs for IL-3Rα and the β-chain results from reduced mRNA degradation. We suggest from these experiments that in human blood eosinophils, IL-5Rα gene transcription and IL-5Rα mRNA metabolism can be regulated by mechanisms that are distinct from those used for IL-3Rα and GM-CSFRα.

Selective inhibition of IL-5 receptor alpha-chain gene transcription by IL-5, IL-3, and granulocyte-macrophage colony-stimulating factor in human blood eosinophils

High affinity receptor for IL-5 (IL-5R), a predominant eosinophil maturation factor, is composed of an IL-5-binding alpha-chain (IL-5R alpha) and a signal-transducing beta-chain that is shared by IL-3 and granulocyte-macrophage CSF (GM-CSF) receptors (IL-3R and GM-CSFR). By Northern blot analysis of mRNAs obtained from normal human blood eosinophils, we show in this report that the hematopoietic cytokines IL-5, IL-3, and GM-CSF down-regulate IL-5R alpha mRNA while up-regulating alpha-chain mRNAs for both IL-3R and GM-CSFR as well as the beta-chain mRNA. More detailed characterization reveals that the down-regulation of IL-5R alpha mRNA is specific to IL-3, IL-5, and GM-CSF; occurs very rapidly (reaching maximum inhibition within 2 h); is cytokine dose dependent; and does not require protein synthesis. Nuclear run-on and mRNA stability experiments demonstrate that cytokine-induced inhibition of IL-5R alpha mRNA accumulation occurs at the level of IL-5R alpha gene transcription, whereas enhanced accumulation of mRNAs for IL-3R alpha and the beta-chain results from reduced mRNA degradation. We suggest from these experiments that in human blood eosinophils, IL-5R alpha gene transcription and IL-5R alpha mRNA metabolism can be regulated by mechanisms that are distinct from those used for IL-3R alpha and GM-CSFR alpha.

Evidence for multiple promoters of the human IL-5 receptor alpha subunit gene: a novel 6-base pair element determines cell-specific promoter function

In addition to a previously characterized promoter (P1), we now show the existence of a second promoter for the human IL-5Ralpha gene. Initially, a genomic region (P2) 5' upstream of human IL-5Ralpha exon 2 was cloned by an inverted PCR. The transcriptional start site was then mapped to a deoxycytidine (C) residue within P2 by analyzing cellular mRNA with both the 5' rapid amplification of cDNA end-PCR and S1 nuclease protection assays. Transfection of eosinophilic HL-60 cells with reporter gene constructs in which either P1 or P2 was linked to the bacterial chloramphenicol acetyltransferase (CAT) gene resulted in CAT expression; little or no CAT expression occurred in other myeloid and nonmyeloid cell lines. Deletion studies showed that a 66-bp region, ranging from -31 to +35, was sufficient to promote CAT expression in eosinophilic HL-60 cells. Analysis of linker-scanning mutants identified a novel 6-bp element (5' CTAATT 3') spanning -19 to -14 that was essential for P2 promoter activity. In electrophoretic mobility shift assays, a P2 region from -31 to +1 containing the unique 6-bp element, when used as a probe, formed a complex with a protein(s) that was found only in the eosinophilic cell line. This binding activity was lost upon replacement of the 6-bp element with a 6-bp linker, suggesting that this element likely serves as the binding site for an eosinophilic HL-60 cell-specific transcription factor(s). Together, these data suggest an important role for P2 promoter in the regulation of eosinophil-specific expression of the human IL-5 receptor alpha gene.

Evidence for multiple promoters of the human IL-5 receptor alpha subunit gene: a novel 6-base pair element determines cell-specific promoter function

In addition to a previously characterized promoter (P1), we now show the existence of a second promoter for the human IL-5Ralpha gene. Initially, a genomic region (P2) 5' upstream of human IL-5Ralpha exon 2 was cloned by an inverted PCR. The transcriptional start site was then mapped to a deoxycytidine (C) residue within P2 by analyzing cellular mRNA with both the 5' rapid amplification of cDNA end-PCR and S1 nuclease protection assays. Transfection of eosinophilic HL-60 cells with reporter gene constructs in which either P1 or P2 was linked to the bacterial chloramphenicol acetyltransferase (CAT) gene resulted in CAT expression; little or no CAT expression occurred in other myeloid and nonmyeloid cell lines. Deletion studies showed that a 66-bp region, ranging from -31 to +35, was sufficient to promote CAT expression in eosinophilic HL-60 cells. Analysis of linker-scanning mutants identified a novel 6-bp element (5' CTAATT 3') spanning -19 to -14 that was essential for P2 promoter activity. In electrophoretic mobility shift assays, a P2 region from -31 to +1 containing the unique 6-bp element, when used as a probe, formed a complex with a protein(s) that was found only in the eosinophilic cell line. This binding activity was lost upon replacement of the 6-bp element with a 6-bp linker, suggesting that this element likely serves as the binding site for an eosinophilic HL-60 cell-specific transcription factor(s). Together, these data suggest an important role for P2 promoter in the regulation of eosinophil-specific expression of the human IL-5 receptor alpha gene.

Tomoxiprole selectively inhibits cyclooxygenase-2

Tomoxiprole is a nonsteroidal anti-inflammatory compound that was reported to have low ulcerogenic potential, a quality that would be expected of a cyclooxygenase-2-selective inhibitor, and, in fact, we find it is selective for this isozyme. In stably transfected COS cells, the compound inhibits recombinant human cyclooxygenase-2 (IC50 = 7 nM) more potently than recombinant cyclooxygenase-1 (IC50 = 240 nM), and similar results are obtained with partially pure ovine enzyme preparations. The compound is thus a very potent as well as selective inhibitor of cyclooxygenase-2. As is true of some other cyclooxygenase-2-selective inhibitors, tomoxiprole inhibition of cyclooxygenase-2 but not cyclooxygenase-1 is time-dependent.

Airway eosinophils, T cells, Th2-type cytokine mRNA, and hyperreactivity in response to aerosol challenge of allergic mice with previously established pulmonary inflammation

Asthma is characterized by acute episodes of nonspecific airway hyperreactivity and chronic pulmonary inflammation exacerbated by stimuli including allergen exposure. In order to reproduce the physiologic and immunologic responses that occur in asthmatic patients, we have characterized a model of antigen-induced inflammation in which allergic mice (B6D2F1) that had been challenged once with aerosolized ovalbumin and had developed a pulmonary cellular infiltrate were rechallenged 1 wk later. Pulmonary inflammation in rechallenged mice was substantially greater than that in single-challenged mice. Eosinophils and activated-memory T cells (CD44+, CD45RBlo) in bronchoalveolar lavage (BAL) fluid accumulated to higher levels and with faster kinetics in response to the second challenge than in response to the first challenge. Eosinophils in lung tissue also accumulated to higher levels but with similar kinetics in response to the second challenge than in response to the first challenge. Similarly, interleukin (IL)-4 and IL-5 steady-state mRNA levels in lung tissue increased after the second challenge and were higher than those measured after a single challenge. Furthermore, treatment of mice with an anti-IL-5 monoclonal antibody 2 h prior to rechallenge inhibited antigen induced eosinophil accumulation in the lungs. In mice challenged twice, peak in vivo bronchoconstrictor responsiveness to acetylcholine was increased following the second challenge compared with that observed following the initial challenge. In contrast, ex vivo tracheal smooth muscle contractile responsiveness to acetylcholine was not altered. Although mucus accumulation and epithelial damage in pulmonary tissue were evident in mice challenged twice, these parameters were slightly reduced compared with those seen at similar times in mice challenged once. Therefore, although these mice exhibit only slight bronchial epithelial damage, the presence of significant inflammation and airway hyperreactivity to acetylcholine as well as slightly increased baseline reactivity demonstrate important similarities with the pathophysiology of asthma.

The inhibitory effects of topically active glucocorticoids on IL-4, IL-5, and interferon-gamma production by cultured primary CD4+ T cells

This study was conducted to directly compare the in vitro efficacy and potency of several glucocorticoids in inhibiting T-cell cytokine production. The glucocorticoids tested were fluticasone propionate, budesonide, triamcinolone acetonide, and beclomethasone dipropionate, which are currently inhaled therapies for the treatment of allergic airway disease. Also used were betamethasone phosphate and the newly developed mometasone furorate. With a novel cell culture system, purified peripheral blood CD4+ T cells from normal donors were stimulated with immobilized anti-CD3 and soluble anti-CD28 monoclonal antibodies to induce high levels of IL-4, IL-5, and interferon-gamma. By cell sorting, it was found that the IL-5 produced originated from memory cells, whereas both memory and naive cells produced interferon-gamma. Mometasone and fluticasone inhibited IL-5 and IL-4 similarly (mometasone IL-5 inhibitory concentration of 50% = 0.27 +/- 0.1 nmol/L and IL-4 = 0.19 +/- 0.08 nmol/L). For both cytokines, the results indicate that mometasone and fluticasone were more potent than beclomethasone, triamcinolone, budesonide, and betamethasone. Of clinical importance is the finding that all steroids demonstrated less efficacy versus interferon-gamma than IL-4 and IL-5. Glucocorticoid reduction of Th2 cytokines with lesser effects on interferon-gamma would serve to reverse the exaggerated Th2 response that contributes to pathophysiology observed in allergic disease. Therefore the use of topically active glucocorticoids with low systemic bioactivity for the treatment of allergic inflammation may be particularly effective in modulating the cytokine activity that is an important component of the allergic response.

Identification of transcription factor binding sites important in the regulation of the human interleukin-5 gene

This study identifies three regions of the human interleukin (IL)-5 promoter involved in binding nuclear factors from activated T cells. DNase I footprinting and mobility shift assays with nuclear proteins from the human T cell clone, SP-B21, demonstrated protein interactions with each of these response elements (REs), located between positions -79 and -45 (RE-I), -123 and -92 (RE-II), and -170 and -130 (RE-III). Two of these regions, RE-II and RE-III, have not previously been described to regulate IL-5 expression in T cells. The RE-II site was shown to be critical for inducible IL-5 promoter activity in transient transfection assays in D10.G4.1 T cells, while the RE-III site functions as a negative regulatory element. The activity of the RE-II site was specifically inhibited by cyclosporin A, and transfection assays with IL-5 constructs containing mutations in the RE-II site showed greatly reduced reporter gene activity. We have defined the sequence involved in stimulation-dependent transcription and have identified constitutive as well as inducible DNA-binding protein complexes that bind to RE-II. Antibodies against at least two members of the nuclear factor of activated T cells (NFAT) family of transcription factors are capable of binding to the IL-5 RE-II complexes, although they can be distinguished from previously identified NFAT-specific complexes by several characteristics.

Expression, purification, and characterization of human cAMP-specific phosphodiesterase (PDE4) subtypes A, B, C, and D

Although four members (A, B, C, and D) of the cAMP-specific phosphodiesterase (PDE4) family have been cloned by different groups, no study comparing the characteristics of purified human PDE4 subtypes has been published. In this study, we have expressed human PDE4 A, B, C, and D in insect (SF9) cells by using the baculovirus expression system, purified the expressed proteins, and compared their characteristics. The recombinant PDE4 subtypes all showed catalytic activity for cAMP with a K(m) of 1-5 microM. V(max) values differed significantly among these subtypes with the following order: C > B > A > D. PDE4 A, B, C, and D showed a very similar Mg2+ dependence profile. PDE4 B and C showed similar pH profiles with the optimal pH being 8.0. The pH profiles of PDE4 A and D were very different from each other and from those of B and C, with the optimal pH being 6.5 and 7.5, respectively. Furthermore, although PDE4 A, B, C, and D were all inhibited by the standard PDE4 inhibitors rolipram, Ro20-1724, and etazolate, the inhibitory potency varied. Thus, by several criteria including kinetics, pH dependency, and inhibitor sensitivity, various PDE4 subtypes differ significantly from one another.

T cells are the predominant source of interleukin-5 but not interleukin-4 mRNA expression in the lungs of antigen-challenged allergic mice

Pulmonary inflammation is characterized by the accumulation of eosinophils and other leukocytes in the lungs of individuals challenged with antigen. Cytokines released by the Th2 lymphocyte subset, especially interleukin-4 (IL-4) and interleukin-5 (IL-5), are also present and thought to play an important role in this process. Previously, we used a model of aerosolized antigen challenge of sensitized mice to show that T cells were necessary for the accumulation of eosinophils and the production of cytokine steady-state messenger ribonucleic acid (mRNA). T cells were isolated from lung tissue at a time (4 h) when high levels of IL-4 and IL-5 mRNAs had accumulated, and from bronchoalveolar lavage fluid (BALF) and lung tissue at a later time (24 h), when inflammation could be detected by lavage. Lung-derived lymphocytes from sensitized challenged mice consisted of approximately 40% Thyl+ T cells (20% CD4+, 13% CD8+, and 6% CD4+/CD8+) and 30% B220+ B cells. Both BALF- and lung-derived T lymphocytes exhibited a similar activated/memory phenotype (CD44+ CD45RBlo), although lung tissue also contained less differentiated cells (CD44+ CD45RBhi). Thyl+ BALF cells isolated by magnetic bead-mediated separation accounted for approximately 88% of the IL-5 mRNA, 21% of the interferon-gamma (IFN-gamma) mRNA, and < 2% of the IL-4 mRNA detected in unseparated samples by reverse transcriptase-polymerase chain reaction (RT-PCR). Thyl+ T cells from lung tissue accounted for approximately 98% and 89% of IL-5 mRNA, 56% and 80% of IFN-gamma mRNA, and 23% and 40% of IL-4 mRNA at 4 h and 24 h after challenge, respectively. These experiments demonstrate that isolated T cells from BALF and lung are responsible for most of the IL-5 mRNA, but not all of the IFN-gamma or IL-4 mRNAs, detected in this model. These results are consistent with human studies indicating T cells as the major source of IL-5 mRNA in the lungs of asthmatic patients.

Transcription of the murine interleukin 5 gene is regulated by multiple promoter elements

Cis-acting regions in the 5'-flank of the mouse interleukin 5 (IL-5) gene involved in the specific and inducible regulation of IL-5 transcription in an untransformed mouse T cell clone, D10.G4.1, have been identified. Transient transfection assays with a series of deletion IL-5 promoter reporter constructs indicate that multiple regulatory elements in the 5'-flanking region of the IL-5 promoter play a role in regulating IL-5 transcription in Th2 cells. Negatively acting elements, NRE I and NRE II, map to the regions between positions -431 and -392 and positions -300 and -261. A positive regulatory element has been mapped to the region between positions -224 and -81. The activity of these elements is dependent on activation of the cells. A 40-bp sequence within this region, termed the IL-5 PRE, has been shown to bind at least two specific nuclear protein complexes from unstimulated and stimulated D10.G4.1 cells. An additional protein complex specific for this site has been identified in nuclear fractions from cells stimulated in the presence of the protein synthesis inhibitor, cycloheximide. Proteins that bind to these elements are likely to be important inducible and specific factors essential for control of IL-5 transcription in response to T cell receptor-mediated signaling events.

Interferon-alpha down-regulates the interleukin-6 receptor in a human multiple myeloma cell line, U266

The effects of interferon-alpha (IFN-alpha) on the interleukin-6 (IL-6) receptor in a multiple myeloma cell line, U266, have been examined. IFN-alpha inhibits [3H]thymidine incorporation in U266 cells in a time- and dose-dependent manner. Furthermore, IFN-alpha inhibits the ability of IL-6 to induce increases in [3H]thymidine incorporation. While IFN-alpha suppresses the ability of 125I-IL-6 to bind to the IL-6 receptor on U266 cells, this effect is not due to competition of IFN-alpha with IL-6 for the IL-6 receptor. Although IFN-alpha induces IL-6 synthesis in the U266 cell, inhibition of IL-6 binding occurs when IL-6 synthesis is minimal. Furthermore, after pretreatment of U266 cells with neutralizing anti-IL-6 antibodies, IFN-alpha still inhibits 125I-IL-6 binding. These data suggest that IFN-alpha inhibition of 125I-IL-6 binding does not involve IL-6 synthesis. IFN-alpha reduces 125I-IL-6 binding without affecting its affinity, suggesting that IFN-alpha inhibits IL-6 receptor expression. Although pretreatment with cycloheximide inhibits 125I-IL-6 binding, IFN-alpha does not cause a selective decrease in the levels of gp130 or IL-6 receptor mRNA at times when 125I-IL-6 binding is inhibited. These observations indicate that IFN-alpha lowers IL-6 receptor density on U266 cells by mechanisms other than competitive binding or lowering IL-6 receptor mRNA production. Receptor down-regulation may be a mechanism of IFN-alpha-induced inhibition of growth in U266 cells.

Relationship of phospholipase C- and phospholipase D-mediated phospholipid remodeling pathways to respiratory burst activation in human neutrophils stimulated by Candida albicans hyphae

Neutrophil (PMN) oxidant release, a key component of defenses against disseminated candidiasis, was preceded by oxidant generation after stimulation by Candida albicans hyphae. Opsonized or unopsonized hyphae triggered phospholipase D (PLD) activation within 5 or 30 s, respectively, forming 1-O-alkyl-phosphatidic acid (alkyl-PA) or 1-O-alkyl-phosphatidyl-ethanol in the presence of ethanol. Ethanol, which competitively lowers phosphatidic acid (PA) production, caused dose-dependent inhibition of superoxide (O2-) generation after hyphal stimulation but altered neither baseline-unstimulated O2- production nor responses to phorbol myristate acetate. PA rises evoked by unopsonized hyphae began 2 min before significant O2- release, also preceding both phospholipase C activation and cytosolic Ca2+ rises. Diacylglycerol (DAG) rose in two distinct phases after stimulation by opsonized or unopsonized hyphae, peaking briefly after 60 or 120 s, respectively, followed by prolonged secondary rises. Initial DAG rises preceded inositol triphosphate elevations evoked by unopsonized hyphae. Though PA rose before DAG, no dephosphorylation of PA to form 1-O-alkyl-DAG was noted. Propranalol, which increases PA accumulation by inhibiting PA phosphohydrolase, lowered PMN O2- responses to hyphae. Early DAG rises temporally overlapped respiratory burst initiation but PMN responses to hyphae were unchanged by a DAG kinase inhibitor, R59022, which blocks phosphorylation of DAG to PA and enhances DAG accumulation. Thus, neither PA nor DAG accumulation individually accounted for triggering PMN O2- responses to hyphae. PLD activation and PA production may facilitate PMN fungicidal responses to hyphae but play an indirect role in initiating the respiratory burst.

Interleukin (IL)-10 inhibits nuclear factor kappa B (NF kappa B) activation in human monocytes. IL-10 and IL-4 suppress cytokine synthesis by different mechanisms

Our previous studies in human monocytes have demonstrated that interleukin (IL)-10 inhibits lipopolysaccharide (LPS)-stimulated production of inflammatory cytokines, IL-1 beta, IL-6, IL-8, and tumor necrosis factor (TNF)-alpha by blocking gene transcription. Using electrophoretic mobility shift assays (EMSA), we now show that, in monocytes stimulated with LPS or TNF alpha, IL-10 inhibits nuclear stimulation of nuclear factor kappa B (NF kappa B), a transcription factor involved in the expression of inflammatory cytokine genes. Several other transcription factors including NF-IL-6, AP-1, AP-2, GR, CREB, Oct-1, and Sp-1 are not affected by IL-10. This selective inhibition by IL-10 of NF kappa B activation occurs rapidly and in a dose-dependent manner and correlates well with IL-10's cytokine synthesis inhibitory activity in terms of both kinetics and dose responsiveness. Furthermore, compounds such as tosylphenylalanyl chloromethyl ketone and pyrrolidinedithiocarbamate that are known to selectively inhibit NF kappa B activation block cytokine gene transcription in LPS-stimulated monocytes. Taken together, these results suggest that inhibition of NF kappa B activation may be an important mechanism for IL-10 suppression of cytokine gene transcription in human monocytes. IL-4, another cytokine that inhibits cytokine mRNA accumulation in monocytes, shows little inhibitory effect on LPS-induced NF kappa B activation. Further examination reveals that, unlike IL-10, IL-4 enhances mRNA degradation and does not suppress cytokine gene transcription. These data indicate that IL-10 and IL-4 inhibit cytokine production by different mechanisms.

IL-10 inhibits transcription of cytokine genes in human peripheral blood mononuclear cells

Upon addition of LPS to human PBMCs, IL-1 beta, IL-6, and TNF-alpha were released in the culture media in a time-dependent manner. Cytokine release began 2 h after LPS addition and maximal release of all three cytokines was observed between 6 and 8 h. Northern analysis revealed that, for each cytokine, mRNA accumulation preceded protein release. When added either 2 h before or at the same time as LPS, IL-10 inhibited both the cytokine release and mRNA accumulation almost completely. Similar inhibition was observed when IL-10 was added 2 h after LPS, a time point that coincided with the onset of the rapid burst of cytokine mRNA accumulation. The inhibitory activity of IL-10 was abrogated by cycloheximide, suggesting an involvement of newly synthesized proteins in IL-10 action. By using nuclear run-on transcription assays, we have found that IL-10 inhibited transcription of all three cytokine genes in LPS-stimulated PBMCs. In contrast, IL-10 moderately enhanced degradation of IL-6 mRNA, but not of mRNAs for IL-1 beta and TNF-alpha. Thus, the present study provides the first evidence that, in human PBMCs, IL-10 inhibits cytokine synthesis by acting mainly at the level of cytokine gene transcription.

IL-10 inhibits transcription of cytokine genes in human peripheral blood mononuclear cells

Upon addition of LPS to human PBMCs, IL-1 beta, IL-6, and TNF-alpha were released in the culture media in a time-dependent manner. Cytokine release began 2 h after LPS addition and maximal release of all three cytokines was observed between 6 and 8 h. Northern analysis revealed that, for each cytokine, mRNA accumulation preceded protein release. When added either 2 h before or at the same time as LPS, IL-10 inhibited both the cytokine release and mRNA accumulation almost completely. Similar inhibition was observed when IL-10 was added 2 h after LPS, a time point that coincided with the onset of the rapid burst of cytokine mRNA accumulation. The inhibitory activity of IL-10 was abrogated by cycloheximide, suggesting an involvement of newly synthesized proteins in IL-10 action. By using nuclear run-on transcription assays, we have found that IL-10 inhibited transcription of all three cytokine genes in LPS-stimulated PBMCs. In contrast, IL-10 moderately enhanced degradation of IL-6 mRNA, but not of mRNAs for IL-1 beta and TNF-alpha. Thus, the present study provides the first evidence that, in human PBMCs, IL-10 inhibits cytokine synthesis by acting mainly at the level of cytokine gene transcription.

Interleukin-10 inhibits interleukin-8 production in human neutrophils

In highly purified human polymorphonuclear leukocyte (PMN) preparations containing less than 0.1% contaminating monocytes, significant amounts of interleukin-8 (IL-8) and small amounts of IL-1 alpha, IL-1 beta, and tumor necrosis factor-alpha (TNF-alpha) were produced by lipopolysaccharide (LPS) stimulation. Contrary to published reports, IL-6 production could not be detected. IL-10 inhibited the production of IL-1 alpha, IL-1 beta, IL-8, and TNF-alpha in LPS-stimulated PMNs, as it did in human blood mononuclear cell (MNC) preparations enriched in monocytes. Subsequent investigation of cytokine synthesis inhibitory effect of IL-10 on PMNs was focused on IL-8. IL-10 inhibited IL-8 synthesis in a dose-dependent manner and, in this regard, it was more potent than IL-4 and transforming growth factor-beta 1 (TGF-B1). In both MNCs and PMNs, degradation of LPS-induced IL-8 mRNA was enhanced by IL-10. Furthermore, as determined by nuclear run-on assays, IL-10 inhibited LPS-induced transcription of IL-8 gene in MNCs. However, in PMNs, run-on assays could not reliably detect IL-8 gene transcription. These results provide the first evidence that the human peripheral neutrophil is a target for inhibition of cytokine synthesis by IL-10, and that IL-10 acts by affecting both gene transcription and mRNA stability.

Phospholipase C and phospholipase D are activated independently of each other in chemotactic peptide-stimulated human neutrophils

When cytochalasin B-treated neutrophils were stimulated with fMet-Leu-Phe (fMLP) in the presence of Ca2+, phospholipase C (PLC) activity, as measured by inositol-1,4,5-triphosphate (IP3) formation, preceded phospholipase D (PLD)-catalyzed breakdown of choline-containing phosphoglycerides to form choline and diradyl-sn-glycero-3-phosphate (phosphatidic acid), suggesting a possible link between PLC and PLD. However, in the absence of cytochalasin B or extracellular Ca2+, PLC was fully activated by fMLP with minimal activation of PLD, indicating that PLC activation alone is not sufficient for PLD activation. Full activation of PLD by fMLP required the simultaneous presence of both Ca2+ and cytochalasin B, a condition that caused no further enhancement of PLC. This result suggests that PLD products are not involved in the regulation of PLC activation. Furthermore, under conditions of complete inhibition of PLC by phorbol 12-myristate 13-acetate (PMA), there was no inhibition of PLD, showing that fMLP can activate PLD in the absence of PLC. Treatment of intact neutrophils with pertussis toxin inhibited both PLC and PLD, with PLC inhibition occurring at lower concentrations that PLD inhibition. These differential effects of pertussis toxin and the observed lack of inhibition of fMLP-stimulated PLD by PMA, which is believed to inactivate G-proteins involved in PLC activation, imply that PLC and PLD are linked to fMLP receptors through distinct G-proteins. Taken together, these observations suggest that, in fMLP-stimulated neutrophils, PLC and PLD are activated through independent mechanisms.

Phospholipase D and cell signaling

Phospholipase D, which hydrolyzes phospholipids (primarily phosphatidylcholine) to generate phosphatidic acid, has emerged as a critical component in cellular signal transduction. Research during the past year has confirmed and extended the view that phosphatidic acid and its dephosphorylated product, sn-1,2-diacylglycerol, are important intracellular second messengers and that the coupling of phospholipase D to specific receptors occurs through multiple mechanisms involving protein kinase C, protein tyrosine kinase, Ca2+ and GTP-binding proteins.

Differential plasma duration of antiplatelet-activating factor and antihistamine activities of oral Sch 37370 in humans

Preclinical studies have established that Sch 37370 (1-acetyl-4-(8-chloro-5,6-dihydro-11H-benzo[5,6]-cyclohepta [1,2-b]pyridin-11-ylidene)piperidine) is an orally active antagonist of platelet-activating factor (PAF) and histamine H1-receptors with potential therapeutic use in the treatment of asthma. To evaluate the efficacy and duration of anti-PAF and antihistamine actions of oral Sch 37370 in humans, a single dose (5 mg/kg) of Sch 37370 was given orally to each of 10 male subjects in a placebo-controlled, double-blind crossover study. Blood samples were drawn before and at various times (2 to 48 hours) after Sch 37370 or placebo. Plasma samples were analyzed for Sch 37370 by a gas chromatographic method, for the anti-PAF activity by measuring the aggregation of platelets stimulated with PAF, and for the antihistamine activity by measuring displacement of [3H]pyrilamine from rat brain membrane binding sites. The plasma anti-PAF activity declined from high levels at 2 hours to barely detectable levels at 24 hours; however, significant activity was still present at 12 hours. The plasma levels of Sch 37370 closely paralleled the anti-PAF profile. The plasma antihistamine activity reached a maximum within 2 to 8 hours and declined thereafter. However, 48 hours after Sch 37370, the antihistamine activity was still present at a significant level in most subjects. It is concluded that, in humans, oral Sch 37370 antagonizes both PAF and histamine with plasma antihistamine activity lasting longer than plasma anti-PAF activity.

Discovery and preliminary pharmacology of Sch 37370, a dual antagonist of PAF and histamine

From a series of amide analogs of the histamine H1 antagonist, azatadine, a potent, orally active, dual platelet-activating factor (PAF) and histamine antagonist, Sch 37370, namely 1-acetyl-4-(8-chloro-5,6-dihydro-11H-benzo- [5,6]cyclohepta[1,2-b]pyridin-11-ylidine)piperidine, was discovered. Sch 37370 selectively inhibits PAF-induced aggregation of human platelets in vitro (IC50 = 0.6 microM), and in vivo inhibits PAF- and histamine-induced bronchospasm in guinea pigs with ED50 values of 6.0 and 2.4 mg/kg p.o., respectively. Sch 37370 is expected to be more efficacious than single mediator antagonists in allergic diseases, such as asthma.

Wheat germ agglutinin and other selected lectins increase synthesis of decay-accelerating factor in human endothelial cells

Decay accelerating factor (DAF) is a cell-surface phosphatidylinositol-anchored protein that protects the cell from inadvertent complement attack by binding to and inactivating C3 and C5 convertases. We have measured DAF on human umbilical vein endothelial cells (HUVEC) by immunoradiometric assay after its removal by phosphatidylinositol-specific phospholipase C or Nonidet P-40 detergent extraction and have previously demonstrated that DAF synthesis can be stimulated by phorbol ester activation of protein kinase C. We now report that although stimulation (4-48 h) of HUVEC with various cytokines, including TNF, IL-1, and IFN-gamma, did not alter DAF levels, wheat germ agglutinin (WGA) (5-50 micrograms/ml), a lectin specific for binding N-acetyl neuraminic acid and N-acetyl glucosamine residues, increased DAF levels fivefold when incubated with HUVEC for 12 to 24 h. The lectins Con A and PHA also stimulated DAF expression twofold, whereas a number of others including Ulex europaeus, Bandeiraea simplicifolia lectin I, and Ricinus communis agglutinin I, which bind to endothelial cells, were inactive. The increase in DAF by WGA was inhibited by N-acetyl glucosamine (10-50 mM) but by neither N-acetyl neuraminic acid nor removal of surface N-acetyl neuraminic acid with neuraminidase. However, succinylated WGA, which has unaltered affinity for N-acetyl glucosamine but not longer binds N-acetyl neuraminic acid, was inactive. These data suggest that the binding of WGA to sugar residues alone is not sufficient to trigger DAF expression and that occupation of additional, specific sites are required. The increase in DAF levels on HUVEC was blocked by inhibitors of RNA and protein synthesis. We conclude that continuous occupation by WGA of specific binding sites on HUVEC triggers events leading to DAF synthesis. This unique, long term stimulation of endothelial cells by lectins may be relevant to cell:cell interactions at the endothelium.