Dataset Information

Cyclic nucleotide phosphodiesterase isoforms in human basophils and mast cells.

ABSTRACT: Cyclic nucleotide phosphodiesterase (PDE) exists as multiple molecular forms. Of the 11 families of PDE identified so far, PDE4, a cAMP-specific PDE, has been identified as the major isoform regulating inflammatory activity. The principle aim of the present study was to determine whether human basophils and human lung mast cells express PDE4. Four sub-classes of PDE4 (A, B, C, and D) have been identified and expression of these was determined by RT-CPR and by western blotting. In basophils, prominent expression of mRNA for PDE4A and PDE4D was observed whereas little if any expression of PDE4B and PDE4C was detected. These findings were paralleled by immunoblotting experiments as human basophils were found to express PDE4A and PDE4D with little evidence for the presence of either PDE4B or PDE4C. By contrast, human lung mast cells expressed very little, if any, mRNA for PDE4 sub-classes although, in some preparations, some modest levels of mRNA for PDE4D were detected. However, there was no evidence, at the protein level, that mast cells express PE4. Overall, these data indicate that basophils express PDE4 (4A and 4D) whereas human lung mast cells do not.

SUBMITTER: Eskandari N

PROVIDER: S-EPMC5806836 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Cyclic nucleotide phosphodiesterase isoforms in human basophils and mast cells.

Eskandari Nahid N Tashrifi Fatemeh F Bastan Reza R Andalib Alrieza A Yousefi Zahra Z Peachell Peter T PT

International journal of immunopathology and pharmacology 20160118 4

Cyclic nucleotide phosphodiesterase (PDE) exists as multiple molecular forms. Of the 11 families of PDE identified so far, PDE4, a cAMP-specific PDE, has been identified as the major isoform regulating inflammatory activity. The principle aim of the present study was to determine whether human basophils and human lung mast cells express PDE4. Four sub-classes of PDE4 (A, B, C, and D) have been identified and expression of these was determined by RT-CPR and by western blotting. In basophils, prom ...[more]

PMID: 26781461

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Project description:Basophil granulocytes and mast cells are recognized for their roles in immunity and are central effectors of diverse immunological disorders. Despite their similarities, there is emerging evidence for non-redundant roles of the circulating yet scarce basophils and tissue-resident mast cells, respectively. Because of their importance in allergic pathogenesis, specific induction of apoptosis in basophils and mast cells may represent an interesting novel treatment strategy. The pro-inflammatory cytokine interleukin-3 serves as a key factor for basophil and mouse mast cell survival. Interleukin-3 increases the expression of anti-apoptotic BCL-2 family members, such as BCL-2, BCL-XL or MCL-1; however, little is known how strongly these individual proteins contribute to basophil survival. Here, we were applying small molecule inhibitors called BH3 mimetics, some of which show remarkable success in cancer treatments, to neutralize the function of anti-apoptotic BCL-2 family members. We observed that expression levels of anti-apoptotic BCL-2 proteins do not necessarily correlate with their respective importance for basophil survival. Whereas naive in vitro-differentiated mouse basophils efficiently died upon BCL-2 or BCL-XL inhibition, interleukin-3 priming rendered the cells highly resistant toward apoptosis, and this could only be overcome upon combined targeting of BCL-2 and BCL-XL. Of note, human basophils differed from mouse basophils as they depended on BCL-2 and MCL-1, but not on BCL-XL, for their survival at steady state. On the other hand, and in contrast to mouse basophils, MCL-1 proved critical in mediating survival of interleukin-3 stimulated mouse mast cells, whereas BCL-XL seemed dispensable. Taken together, our results indicate that by choosing the right combination of BH3 mimetic compounds, basophils and mast cells can be efficiently killed, even after stimulation with potent pro-survival cytokines such as interleukin-3. Because of the tolerable side effects of BH3 mimetics, targeting basophils or mast cells for apoptosis opens interesting possibilities for novel treatment approaches.

Project description:Phosphodiesterase 3A (PDE3A) is a major regulator of cAMP in cardiomyocytes. PDE3 inhibitors are used for acute treatment of congestive heart failure, but are associated with increased incidence of arrhythmias and sudden death with long-term use. We previously reported that chronic PDE3A downregulation or inhibition induced myocyte apoptosis in vitro. However, the cardiac protective effect of PDE3A has not been demonstrated in vivo in disease models. In this study, we examined the role of PDE3A in regulating myocardial function and survival in vivo using genetically engineered transgenic mice with myocardial overexpression of the PDE3A1 isozyme (TG). TG mice have reduced cardiac function characterized by reduced heart rate and ejection fraction (52.5±7.8% vs. 83.9±4.7%) as well as compensatory expansion of left ventricular diameter (4.19±0.19mm vs. 3.10±0.18mm). However, there was no maladaptive increase of fibrosis and apoptosis in TG hearts compared to wild type (WT) hearts, and the survival rates also remained the same. The diminution of cardiac contractile function is very likely attributed to a decrease in beta-adrenergic receptor (β-AR) response in TG mice. Importantly, the myocardial infarct size (4.0±1.8% vs. 24.6±3.8%) and apoptotic cell number (1.3±1.0% vs. 5.6±1.5%) induced by ischemia/reperfusion (I/R) injury were significantly attenuated in TG mice. This was associated with decreased expression of inducible cAMP early repressor (ICER) and increased expression of anti-apoptotic protein BCL-2. To further verify the anti-apoptotic effects of PDE3A1, we performed in vitro apoptosis study in isolated adult TG and WT cardiomyocytes. We found that the apoptotic rates stimulated by hypoxia/reoxygenation or H2O2 were indeed significantly reduced in TG myocytes, and the differences between TG and WT myocytes were completely reversed in the presence of the PDE3 inhibitor milrinone. These together indicate that PDE3A1 negatively regulates β-AR signaling and protects against I/R injury by inhibiting cardiomyocyte apoptosis.

Dataset Information

Cyclic nucleotide phosphodiesterase isoforms in human basophils and mast cells.

Publications

Cyclic nucleotide phosphodiesterase isoforms in human basophils and mast cells.

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