The relationship and diagnostic efficacy of N-terminal propeptide type III collagen in pathological changes associated with non-alcoholic steatohepatitis.

OBJECTIVE: This study delves into the role of N-terminal propeptide type III collagen (PIIINP) in the diagnosis and management of liver pathological changes associated with non-alcoholic steatohepatitis (NASH). PATIENTS AND METHODS: We collected baseline information, pathological data, and serum PIIINP levels of 168 patients diagnosed with non-alcoholic fatty liver disease (NAFLD) via ultrasound imaging in our hospital. Based on the non-alcoholic fatty liver disease activity score (NAS), patients with different NAFLD patterns were divided into a Definite NASH group and a Not/borderline group. Differences in PIIINP levels and pathological features between the two groups were compared and analyzed. The diagnostic value of PIIINP for NASH was evaluated using the receiver operating characteristic (ROC) curve. RESULTS: Patients with NASH exhibited significantly higher values of homeostatic model assessment for insulin resistance (HOMA-IR), fibrosis biomarker fibrosis-4 (FIB-4), aminotransferase-to-platelet ratio index (APRI), and serum PIIINP levels than those classified as Not/borderline. A marked increase in the serum concentrations of PIIINP was observed with the severity of fatty degeneration, lobular inflammation, and hepatocellular ballooning. The AUC of PIIINP for diagnosing definite NASH was 0.766 (95% CI: 0.694, 0.839), APRI was 0.634 (95% CI: 0.549, 0.718), and FIB-4 was 0.621 (95% CI: 0.534, 0.708). The AUC of PIIINP for diagnosing definite NASH was significantly higher than that of APRI and FIB-4 (all p<0.05). Utilizing the predetermined threshold values for diagnostic parameters, the PIIINP measure demonstrated a sensitivity of 71.6% and a specificity of 73.6% in diagnosing definitive NASH when its value exceeded 7.72 ng/dL. This yielded a Youden index of 0.45. Similarly, when the APRI measure exceeded 0.21, it exhibited a sensitivity of 60.5% and a specificity of 63.2%, resulting in a Youden index of 0.24. Moreover, when the FIB-4 index surpassed 0.26, it showed a sensitivity of 46.9% and a specificity of 79.3%, culminating in a Youden index of 0.26. CONCLUSIONS: NASH patients in this study exhibited significantly elevated PIIINP serum levels, which were closely associated with hepatocyte pathological changes. PIIINP demonstrated superior competence in diagnosing NASH than APRI and FIB-4 and thus offers a viable alternative for the clinical diagnosis of NASH.

[Influential factors related to osteoradionecrosis of the mandible in oral and maxillofacial cancer patients following radiotherapy].

Objective: To identify risk factors associated with mandibular osteoradionecrosis (ORN) in oral and maxillofacial cancer patients following radiotherapty and to provide scientific basis for the etiological research and clinical prevention of mandibular ORN. Methods: A retrospective study was conducted in patients with oral and maxillofacial-head and neck cancer during the period from January 2013 to December 2015. Influential factors related to mandibular ORN were screened by single factor analysis, Lasso and Logistic regression analysis. Results: A total of 757 patients were analyzed, and the total incidence of mandibular ORN was 12.0%(91/757). There were 443 males and 314 females, aged (51.8±13.7) years. Thirty-five related factors were screened to 28 by single factor analysis. It was determined by Lasso regression analysis that, radiation doses (OR=1.135, P=0.034, 95%CI: 1.089-1.232), T classification (OR=2.586, P=0.001, 95%CI: 1.482-4.512), mandibular surgery (OR=9.101, P<0.001, 95%CI: 2.796-29.630), periodontitis (OR=6.089, P<0.001, 95%CI: 2.708-13.693), diabetes (OR=4.467, P=0.002, 95%CI: 1.705-11.704), tooth extraction after radiotherapy (OR=3.228, P=0.001, 95%CI: 1.640-6.350), dental caries (OR=2.911, P=0.009, 95%CI: 1.300-6.516), periapical periodontitis (OR=2.726, P=0.016, 95%CI: 1.209-6.145), smoking (OR=4.438, P=0.002, 95%CI: 1.702-11.571) and unilateral/bilateral radiotherapy (OR=2.225, P=0.028, 95%CI: 1.090-4.545) were significantly associated with developing mandibular ORN. Conclusions: Ten main risk factors for mandibular ORN were identified through the single center, large sample, retrospective analysis, which has a certain value for clinical prevention of mandibular ORN. Prospective, randomized controlled trials and long-term follow-up are still needed.

Silencing of miR-330-5p stimulates osteogenesis in bone marrow mesenchymal stem cells and inhibits bone loss in osteoporosis by activating Bgn-mediated BMP/Smad pathway.

OBJECTIVE: To illustrate the role of micro ribonucleic acid (miR)-330-5p in regulating osteogenesis through biglycan (Bgn)-mediated bone morphogenetic protein (BMP)/Smad pathway. MATERIALS AND METHODS: A mouse model of osteoporosis (OP) was established by ovariectomy (OVX). BMD and miR-330-5p levels in mice undergoing sham operation or OVX were determined. BMD and BV/TV in OP mice with in vivo knockdown of miR-330-5p were measured by Micro-CT. After silencing of miR-330-5p in mouse primary bone marrow stromal cells (BMSCs), expression changes in osteogenesis-associated genes, ALP activity, and mineralization ability were assessed. Subsequently, the interaction between miR-330-5p and Bgn was examined by Dual-Luciferase reporter gene assay and Western blotting. Then, Bgn levels in BMSCs undergoing osteogenesis at different time points were measured. At last, the regulatory effects of miR-330-5p/Bgn axis on the BMP/Smad pathway, ALP activity, and mineralization ability in BMSCs were evaluated. RESULTS: BMD was decreased and miR-330-5p was upregulated in OP mice. OP mice with in vivo knockdown of miNA-330-5p presented higher BMD and BV/TV than controls. Transfection with miR-330-5p inhibitor upregulated osteogenesis-associated genes, ALP activity, and mineralization ability in BMSCs. Bgn was time-dependently upregulated in BMSCs undergoing osteogenesis, which was indicated to be the target gene of miR-330-5p. Besides, Bgn level was negatively regulated by miR-330-5p. Importantly, Bgn was able to reverse the regulatory effects of miR-330-5p on the BMP/Smad pathway, ALP activity, and mineralization ability in BMSCs. CONCLUSIONS: Knockdown of miR-330-5p facilitates osteogenesis in BMSCs through the Bgn-induced BMP/Smad pathway, thus alleviating the progression of OP.

[Construction and analysis of competitive endogenous RNA regulatory network related to gastric cancer].

Objective: To construct the competitive endogenous RNA (ceRNA) network related to gastric cancer and explore the molecular mechanism. Methods: The expression profiles of lncRNA, miRNA and mRNA in gastric cancer and paracancer tissues were analyzed by biochip technology, edgeR package in R software was used to filtrate differential expression genes (multiple change of >1.5 times, P<0.05) and volcano map was drawn. Based on the online miRNA-lncRNA prediction tool lncBase database and the miRNA Target gene prediction database (miRTarBase, target-scan, miRDB, starBase), the relationship between miRNA, lncRNA and mRNA was predicted. Cytoscape software was used to construct lncRNA-miRNA-mRNA ceRNA network and key genes (hub genes) were identified based on cytohubba calculation of degree score of each node. Then Hub genes related to the prognosis of gastric cancer were verified in the TCGA database. The GO and KEGG enrichment analysis of differentially expressed mRNA was performed using the online biological information annotation database DAVID, P<0.05 and false discovery rate (FDR)<0.05 were used as cut-off criteria. R software was used to download the RNA sequencing data and mirna-seq data of gastric cancer and adjacent tissues in TCGA database, edgeR package was used to screen out differentially expressed mRNA, miRNA and lncRNA, and some differentially expressed genes in our data were verified. In OncoLnc database, STAD project of TCGA data was selected and hub gene was input. Patients were divided into two groups based on the median value for hub genes and Kaplan-meier analysis was performed. Results: The differentially expressed 766 mRNA, 110 lncRNA and 10 miRNA were screened out, among them 90 mRNA, 4 lncRNA and 6 miRNA were used to construct the ceRNA network, and 2 of the 20 hub genes were related to the prognosis of patients. MLK7-AS1, SPP1, SULF1, hsa-miR-1307-3p were upregulated in gastric cancer tissues from our biochip, while MT2A, MT1X were downregulated, which were consistent with the results of TCGA gastric cancer database. The differentially expressed mRNAs were significantly enriched in the biological process (BP) and the mineral absorption pathway. CHST1 was negatively correlated while miR-183-5p was positively corelated with the survival of patients. Conclusion: The establishment of ceRNA network for gastric cancer is conducive to further understanding of the molecular biological mechanism. CHST1 and miR-183-5p can be used as prognostic factors of gastric cancer.

[Trend in proportion and clinicopathological characteristics of young women with stage â a2 to â ¡a2 cervical cancer].

Objective: To analyze the 13 years trend in proportion, risks factors and clinicopathological characteristics of young women with stage Ⅰa2 to Ⅱa2 cervical cancer by using multi-center data of cervical cancer in China. Methods: The clinicopathological data of 46 313 patients with cervical cancer treated from 37 hospitals in China were obtained from January 2004 to December 2016. Using clinical and pathologic data, each patient's stage was reclassified by the 2018 International Federation of Gynecology and Obstetrics (FIGO) staging system. A total of 19 041 patients were selected according to the following criteria: FIGO stage Ⅰa2 to Ⅱa2, underwent type B or C radical hysterectomy and pelvic lymphadenectomy. All the patients were divided into two groups: the study group of 1 888 patients aged 35 years or younger and the control group of 17 153 patients aged over 35 years. The 13 years trend in proportion of young women with stage Ⅰa2 to Ⅱa2 cervical cancer, risks factors and clinicopathological characteristics of two groups were retrospectively analyzed. Results: (1) The total number of hospitalized patients with stage Ⅰa2 to Ⅱa2 cervical cancer increased annually. However, a downward trend of patients aged 35 years or younger was observed (P<0.01) . The constituent ratio of patients aged 35 years or younger was significantly greater during 2004-2010 than that during 2011-2016 [12.6% (820/6 484) and 8.5% (1 068/12 557) , respectively; χ(2)=82.101, P<0.01]. (2) Compared with patients aged over 35 years, patients aged 35 years or younger had an earlier age at menarche, a later age at marriage, lesser gravida and parity (all P<0.01). The positive rate of high-risk HPV infection was not statistically different between two groups (all P>0.05). (3) The proportions of stage Ⅰ, exophytic type and non-squamous histological type in patients aged 35 years or younger were clearly higher than those in patients aged over 35 years (83.4% vs 68.5%, P<0.01; 63.2% vs 56.2%, P<0.01; 13.9% vs 12.0%, P<0.05, respectively). Whereas the poor differentiation ratios of the two groups had no statistical significance (P>0.05). (4) As for the postoperative pathological risk factors, the rate of surgical margin involvement in patients aged 35 years or younger was lower than that aged over 35 years (1.1% vs 1.8%, P<0.05), and the rate of depth of stromal invasion >1/2 in patients aged 35 years or younger was lower than that in patients aged over 35 years (40.1% vs 50.9%, P<0.01). In addition, there were no significant difference in parametrial margin involvement, tumor size and lymph vascular space invasion between two groups (all P>0.05). Conclusions: The trend in proportion among hospitalized patients for stage Ⅰa2 to Ⅱa2 cervical cancer in young women is decreasing yearly. Compared with cervical cancer in middle-aged and elderly women, cervical cancer in young women have an earlier age at menarche, a higher proportion of stage Ⅰ patients and non-squamous histological type. In terms of the postoperative pathological risk factors, the rate of surgical margin involvement and depth of stromal invasion >1/2 in young women with cervical cancer are lower than in middle-aged and elderly women.

Correction: USP17 mediates macrophage-promoted inflammation and stemness in lung cancer cells by regulating TRAF2/TRAF3 complex formation.

A correction to this paper has been published and can be accessed via a link at the top of the paper.

Synergistic effect of phosphodiesterase 4 inhibitor and serum on migration of endotoxin-stimulated macrophages.

Macrophage migration is an essential step in host defense against infection and wound healing. Elevation of cAMP by inhibiting phosphodiesterase 4 (PDE4), enzymes that specifically degrade cAMP, is known to suppress various inflammatory responses in activated macrophages, but the role of PDE4 in macrophage migration is poorly understood. Here we show that the migration of Raw 264.7 macrophages stimulated with LPS was markedly and dose-dependently induced by the PDE4 inhibitor rolipram as assessed by scratch wound healing assay. Additionally, this response required the involvement of serum in the culture medium as serum starvation abrogated the effect. Further analysis revealed that rolipram and serum exhibited synergistic effect on the migration, and the influence of serum was independent of PDE4 mRNA expression in LPS-stimulated macrophages. Moreover, the enhanced migration by rolipram was mediated by activating cAMP/exchange proteins directly activated by cAMP (Epac) signaling, presumably via interaction with LPS/TLR4 signaling with the participation of unknown serum components. These results suggest that PDE4 inhibitors, together with serum components, may serve as positive regulators of macrophage recruitment for more efficient pathogen clearance and wound repair.

[The influence of Thymidine Phosphorylase genetic variation on clinical outcomes and safety of colorectal cancer patients received adjuvant chemotherapy after R0 resection].

Objective: To study the association between Thymidine Phosphorylase (TYMP) genetic variation and clinical outcomes and safety of postoperative colorectal cancer (CRC) patients. Methods: A total of 235 patients with colorectal cancer underwent surgical treatment were included in this retrospective analysis. Peripheral blood and the postoperative tissue specimen of the CRC patients were collected for the genotyping of polymorphism and TYMP mRNA expression, respectively. The correlation between polymorphism and clinical outcomes and safety of postoperative CRC patients were analysed. Results: Located in the upstream, 5633C>T was of clinical significance. The prevalence of 5633C>T in TYMP among the CRC patients were as follows: CC genotype 149 cases (63.40%), CT genotype 73 cases (31.06%), TT genotype 13 cases (5.54%), minor allele frequency of 5633C>T is 0.21. The distribution of three genotypes was in accordance with Hardy-Weinberg Equilibrium (P=0.313). CT genotype and TT genotype patients were merged in the comparison of prognosis. The survival analysis of patients with different genotypes found that the median Overall Survival (OS) of CT/TT genotype and CC genotype were 5.8 and 4.5 year, which was statistically significant (P=0.009). Adjusted in multivariate Cox regression analysis, CT/TT genotype was an independent favorable factor for OS (HR=0.67, P=0.015). Additionally, of the 87 postoperative tissue specimens, the results showed that the expression of TYMP in cancer tissues of the patients with CT or TT genotypes were significantly higher than those of the wild type CC genotype patients (P=0.019). And the safety analysis showed that the incidence of grade 3 hand-foot syndrome among CT/TT genotype patients were higher than that of CC genotype patients (33.72% vs 20.13%, OR=1.68, P=0.021). Conclusion: The polymorphism 5633C>T of TYMP may impact the prognosis of CRC patients received adjuvant chemotherapy by influencing the mRNA expression of TYMP.

USP17 mediates macrophage-promoted inflammation and stemness in lung cancer cells by regulating TRAF2/TRAF3 complex formation.

Macrophage accumulation and inflammation in the lung owing to stresses and diseases is a cause of lung cancer development. However, molecular mechanisms underlying the interaction between macrophages and cancer cells, which drive inflammation and stemness in cancers, are poorly understood. In this study, we investigated the expression of ubiquitin-specific peptidase 17 (USP17) in lung cancers, and role of elevated USP17 in the interaction between macrophages and lung cancer cells. USP17 expression in lung cancers was associated with poor prognosis, macrophage, and inflammatory marker expressions. Macrophages promoted USP17 expression in cancer cells. TNFR-associated factor (TRAF) 2-binding and TRAF3-binding motifs were identified in USP17, through which it interacted with and disrupted the TRAF2/TRAF3 complex. This stabilized its client proteins, enhanced inflammation and stemness in cancer cells, and promoted macrophage recruitment. In different animal studies, co-injection of macrophages with cancer cells promoted USP17 expression in tumors and tumor growth. Conversely, depletion of macrophages in host animals by clodronate liposomes reduced USP17 expression and tumor growth. In addition, overexpression of USP17 in cancer cells promoted tumor growth and inflammation-associated and stemness-associated gene expressions in tumors. These results suggested that USP17 drives a positive-feedback interaction between macrophages and cancer cells to enhance inflammation and stemness in cancer cells, and promotes lung cancer growth.

Involvement of M1 Macrophage Polarization in Endosomal Toll-Like Receptors Activated Psoriatic Inflammation.

Psoriasis is a chronic inflammatory skin disorder that affects ~2%-3% of the worldwide population. Inappropriate and excessive activation of endosomal Toll-like receptors 7, 8, and 9 (TLRs 7-9) at the psoriatic site has been shown to play a pathogenic role in the onset of psoriasis. Macrophage is a major inflammatory cell type that can be differentiated into phenotypes M1 and M2. M1 macrophages produce proinflammatory cytokines, and M2 macrophages produce anti-inflammatory cytokines. The balance between these two types of macrophages determines the progression of various inflammatory diseases; however, whether macrophage polarization plays a role in psoriatic inflammation activated by endosomal TLRs has not been investigated. In this study, we investigated the function and mechanism of macrophages related to the pathogenic role of TLRs 7-9 in the progression of psoriasis. Analysis of clinical data in database revealed significantly increased expression of macrophage markers and inflammatory cytokines in psoriatic tissues over those in normal tissues. In animal studies, depletion of macrophages in mice ameliorated imiquimod, a TLR 7 agonist-induced psoriatic response. Imiquimod induced expression of genes and cytokines that are signature of M1 macrophage in the psoriatic lesions. In addition, treatment with this TLR 7 agonist shifted macrophages in the psoriatic lesions to a higher M1/M2 ratio. Both of the exogenous and endogenous TLR 7-9 ligands activated M1 macrophage polarization. M1 macrophages expressed higher levels of proinflammatory cytokines and TLRs 7-9 than M2 macrophages. These results suggest that by rendering macrophages into a more inflammatory status and capable of response to their ligands in the psoriatic sites, TLR 7-9 activation drives them to participate in endosomal TLR-activated psoriatic inflammation, resulting in an amplified inflammatory response. Our results also suggest that blocking M1 macrophage polarization could be a strategy which enables inhibition of psoriatic inflammation activated by these TLRs.

Phosphodiesterase 4B negatively regulates endotoxin-activated interleukin-1 receptor antagonist responses in macrophages.

Activation of TLR4 by lipopolysaccharide (LPS) induces both pro-inflammatory and anti-inflammatory cytokine production in macrophages. Type 4 phosphodiesterases (PDE4) are key cAMP-hydrolyzing enzymes, and PDE4 inhibitors are considered as immunosuppressors to various inflammatory responses. We demonstrate here that PDE4 inhibitors enhance the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1Ra) secretion in LPS-activated mouse peritoneal macrophages, and this response was regulated at the transcriptional level rather than an increased IL-1Ra mRNA stability. Studies with PDE4-deficient macrophages revealed that the IL-1Ra upregulation elicited by LPS alone is PKA-independent, whereas the rolipram-enhanced response was mediated by inhibition of only PDE4B, one of the three PDE4 isoforms expressed in macrophages, and it requires PKA but not Epac activity. However, both pathways activate CREB to induce IL-1Ra expression. PDE4B ablation also promoted STAT3 phosphorylation (Tyr705) to LPS stimulation, but this STAT3 activation is not entirely responsible for the IL-1Ra upregulation in PDE4B-deficient macrophages. In a model of LPS-induced sepsis, only PDE4B-deficient mice displayed an increased circulating IL-1Ra, suggesting a protective role of PDE4B inactivation in vivo. These findings demonstrate that PDE4B negatively modulates anti-inflammatory cytokine expression in innate immune cells, and selectively targeting PDE4B should retain the therapeutic benefits of nonselective PDE4 inhibitors.

Phosphodiesterase 4 and its inhibitors in inflammatory diseases.

Type 4 cyclic nucleotide phosphodiesterases (PDE4) are a family of low km 3',5'-cyclic adenosine monophosphate (cAMP)-specific phosphodiesterases including at least 20 isozymes encoded by four genes (PDE4A, PDE4B, PDE4C, and PDE4D) in mammals. Each PDE4 gene plays a special, nonredundant role in the control of cell function even though the four subfamilies share the highly conserved catalytic domain and upstream conserved region (UCR) 1 and UCR2 motifs of the regulatory domain. By their wide tissue distribution as well as differential expression and regulation among various cell types, PDE4s are viewed as critical regulators of intracellular cAMP levels, cAMP signaling, and signal compartmentalization. By increasing cAMP levels, PDE4 inhibitors show a broad spectrum of anti-inflammatory effects in almost all inflammatory cells. Many PDE4 inhibitors have been evaluated in clinical trials for various inflammatory conditions. Developed inhibitors, including the recently approved and marketed roflumilast, have considerable efficacy, but they also have adverse effects such as nausea and emesis which limit their dosing and subsequently their immunomodulatory activity. Thus, the development of PDE4 inhibitors with improved therapeutic indexes has been a major focus of pharmaceutical research for the treatment of chronic inflammatory diseases. Recent PDE4 gene knockout studies strongly suggest that PDE4 inhibitors with PDE4B selectivity may retain the anti-inflammatory effects while limiting side effects. Development of PDE4 inhibitors with different delivery routes, such as topical application and inhalation, is also a promising approach for the treatment of pulmonary inflammatory conditions and dermatitis. This review includes a brief overview of the domain structure and function of PDE4 isozymes, the role of PDE4s in inflammatory cell responses, and the potential therapeutic utility of PDE4 inhibitors in inflammatory diseases.

Critical role of PDE4D in beta2-adrenoceptor-dependent cAMP signaling in mouse embryonic fibroblasts.

One of the defining properties of beta2-adrenergic receptor (beta(2)AR) signaling is the transient and rapidly reversed accumulation of cAMP. Here we have investigated the contribution of different PDE4 proteins to the generation of this transient response. To this aim, mouse embryonic fibroblasts deficient in PDE4A, PDE4B, or PDE4D were generated, and the regulation of PDE activity, the accumulation of cAMP, and CREB phosphorylation in response to isoproterenol were monitored. Ablation of PDE4D, but not PDE4A or PDE4B, had a major effect on the beta-agonist-induced PDE activation, with only a minimal increase in PDE activity being retained in PDE4D knock-out (KO) cells. Accumulation of cAMP was markedly enhanced, and the kinetics of cAMP accumulation were altered in their properties in PDE4DKO but not PDE4BKO cells. Modest effects were observed in PDE4AKO mouse embryonic fibroblasts. The return to basal levels of both cAMP accumulation and CREB phosphorylation was greatly delayed in the PDE4DKO cells, suggesting that PDE4D is critical for dissipation of the beta2AR stimulus. This effect of PDE4D ablation was in large part due to inactivation of a negative feedback mechanism consisting of the PKA-mediated activation of PDE4D in response to elevated cAMP levels, as indicated by experiments using the cAMP-dependent protein kinase inhibitors H89 and PKI. Finally, PDE4D ablation affected the kinetics of beta2AR desensitization as well as the interaction of the receptor with Galphai. These findings demonstrate that PDE4D plays a major role in shaping the beta2AR signal.

Phosphodiesterase 4D deficiency in the ryanodine-receptor complex promotes heart failure and arrhythmias.

Phosphodiesterases (PDEs) regulate the local concentration of 3',5' cyclic adenosine monophosphate (cAMP) within cells. cAMP activates the cAMP-dependent protein kinase (PKA). In patients, PDE inhibitors have been linked to heart failure and cardiac arrhythmias, although the mechanisms are not understood. We show that PDE4D gene inactivation in mice results in a progressive cardiomyopathy, accelerated heart failure after myocardial infarction, and cardiac arrhythmias. The phosphodiesterase 4D3 (PDE4D3) was found in the cardiac ryanodine receptor (RyR2)/calcium-release-channel complex (required for excitation-contraction [EC] coupling in heart muscle). PDE4D3 levels in the RyR2 complex were reduced in failing human hearts, contributing to PKA-hyperphosphorylated, "leaky" RyR2 channels that promote cardiac dysfunction and arrhythmias. Cardiac arrhythmias and dysfunction associated with PDE4 inhibition or deficiency were suppressed in mice harboring RyR2 that cannot be PKA phosphorylated. These data suggest that reduced PDE4D activity causes defective RyR2-channel function associated with heart failure and arrhythmias.

Specific role of phosphodiesterase 4B in lipopolysaccharide-induced signaling in mouse macrophages.

Cyclic nucleotide signaling functions as a negative modulator of inflammatory cell responses, and type 4 phosphodiesterases (PDE4) are important regulators of this pathway. In this study, we provide evidence that only one of the three PDE4 genes expressed in mouse peritoneal macrophages is involved in the control of TLR signaling. In these cells, LPS stimulation of TLR caused a major up-regulation of PDE4B but not the paralogs PDE4A or PDE4D. Only ablation of PDE4B impacted LPS signaling and TNF-alpha production. TNF-alpha mRNA and protein were decreased by >50% in PDE4B-/-, but not in PDE4A-/- or PDE4D-/- macrophages. The PDE4 selective inhibitors rolipram and roflumilast had no additional inhibitory effect in macrophages deficient in PDE4B, but suppressed the TNF-alpha response in the other PDE4 null cells. The inhibition of TNF-alpha production that follows either genetic ablation or acute inhibition of PDE4B is cAMP-dependent and requires protein kinase A activity. However, no global changes in cAMP concentration were observed in the PDE4B-/- macrophages. Moreover, ablation of PDE4B protected mice from LPS-induced shock, suggesting that altered TLR signaling is retained in vivo. These findings demonstrate the highly specialized function of PDE4B in macrophages and its critical role in LPS signaling. Moreover, they provide proof of concept that a PDE4 inhibitor with subtype selectivity retains useful pharmacological effects.

Phosphodiesterase 4D is required for beta2 adrenoceptor subtype-specific signaling in cardiac myocytes.

beta adrenoceptor (betaAR) signaling is finely regulated to mediate the sympathetic nervous system control of cardiovascular function. In neonatal cardiac myocytes, beta1AR activates the conventional Gs/cAMP pathway, whereas beta2AR sequentially activates both the Gs and Gi pathways to regulate the myocyte contraction rate. Here, we show that phosphodiesterase 4D (PDE4D) selectively impacts signaling by beta2AR in neonatal cardiac myocytes, while having little or no effect on beta1AR signaling. Although beta2AR activation leads to an increase in cAMP production, the cAMP generated does not have access to the protein kinase A-dependent signaling pathways by which the beta1AR regulates the contraction rate. However, this restricted access is lost in the presence of PDE4 inhibitors or after ablation of PDE4D. These results not only suggest that PDE4D is an integral component of the beta2AR signaling complex, but also underscore the critical role of subcellular cAMP regulation in the complex control of receptor signaling. They also illustrate a mechanism for fine-tuned betaAR subtype signaling specificity and intensity in the cardiac system.

Nonredundant function of phosphodiesterases 4D and 4B in neutrophil recruitment to the site of inflammation.

Neutrophils have been implicated in the pathogenesis of many inflammatory lung diseases, including chronic obstructive pulmonary disease and asthma. With this study, we investigated how disruption of cAMP signaling impacts the function of neutrophil recruitment to the lung. Four genes code for type 4 phosphodiesterases (PDE4s), enzymes critical for regulation of cAMP levels and cell signaling. Ablation of two of these genes, PDE4B and PDE4D, but not PDE4A, has profound effects on neutrophil function. In a paradigm of mouse lung injury induced by endotoxin inhalation, the number of neutrophils recovered in the bronchoalveolar lavage was markedly decreased in PDE4D(-/-) and PDE4B(-/-) mice 4 and 24 h after exposure to LPS. Acute PDE4 inhibition with rolipram had additional inhibitory effects on neutrophil migration in PDE4B(-/-) and, to a lesser extent, PDE4D(-/-) mice. This decreased neutrophil recruitment occurred without major changes in chemokine accumulation in bronchoalveolar lavage, suggesting a dysfunction intrinsic to neutrophils. This hypothesis was confirmed by investigating the expression of adhesion molecules on the surface of neutrophils and chemotaxis in vitro. CD18 expression was decreased after ablation of both PDE4B and PDE4D, whereas CD11 expression was not significantly affected. Chemotaxis in response to KC and macrophage inflammatory protein-2 was markedly reduced in PDE4B(-/-) and PDE4D(-/-) neutrophils. The effect of PDE4 ablation on chemotaxis was comparable, but not additive, to the effects of acute PDE4 inhibition with rolipram. These data demonstrate that PDE4B and PDE4D play complementary, but not redundant, roles in the control of neutrophil function.

EGF-like growth factors as mediators of LH action in the ovulatory follicle.

Before ovulation in mammals, a cascade of events resembling an inflammatory and/or tissue remodeling process is triggered by luteinizing hormone (LH) in the ovarian follicle. Many LH effects, however, are thought to be indirect because of the restricted expression of its receptor. Here, we demonstrate that LH stimulation induces the transient and sequential expression of the epidermal growth factor (EGF) family members amphiregulin, epiregulin, and beta-cellulin. Incubation of follicles with these growth factors recapitulates the morphological and biochemical events triggered by LH, including cumulus expansion and oocyte maturation. Thus, these EGF-related growth factors are paracrine mediators that propagate the LH signal throughout the follicle.

PDE4D plays a critical role in the control of airway smooth muscle contraction.

The airways of mice deficient in the cAMP phosphodiesterase PDE4D gene are refractory to muscarinic cholinergic stimulation. This study was undertaken to determine whether altered smooth muscle contractility causes the PDE4D-/- phenotype. A major disruption in contractility was observed in isolated PDE4D-/- tracheas, with a 60% reduction in maximal tension and a fivefold decrease in sensitivity to muscarinic cholinergic agonists. Conversely, responses to KCl or arginine vasopressin were unaffected. PDE4D is the predominant PDE4 form in tracheal extracts and PDE4D mRNA is expressed in smooth muscle where muscarinic binding sites are most abundant. Cyclic AMP accumulation in response to acute G(s)alpha-coupled receptor stimulation was increased up to fourfold in the airway of PDE4D-/- mice when compared with wild-type. This increase in cAMP was associated with an increased sensitivity to PGE2-induced relaxation of the PDE4D-/-tracheas. Furthermore, a blockade of prostanoid accumulation in PDE4D-/- tracheas restored the response to muscarinic cholinergic stimulation in vitro and in vivo. These results demonstrate that PDE4D plays a key role in balancing relaxant and contracting cues in airway smooth muscle, suggesting that natural mutations in the PDE4D gene have profound effects on airway tone.