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Background: Weight loss is reported with oral roflumilast, which is approved for chronic obstructive pulmonary disease (COPD). Recently, the drug has shown efficacy in psoriasis, a disease strongly linked to overweight/obesity., Objective: To describe the effects of oral roflumilast on body weight and cardio-metabolic parameters in patients with psoriasis., Methods: Posthoc analyses from the PSORRO study, where patients with moderate-to-severe plaque psoriasis were randomized 1:1 to oral roflumilast 500 μg once-daily or placebo for 12 weeks, followed by active, open-label treatment through week 24 in both groups. Changes in body weight, blood pressure, gastrointestinal symptoms, and laboratory tests were registered. No lifestyle or dietary interventions were applied., Results: Forty-six patients were randomized. Baseline characteristics across groups were comparable; mean weight was 103.6 kg. In patients receiving roflumilast, median weight change was -2.6% and -4% at week 12 and 24, respectively. Corresponding numbers were 0.0% and 1.3% in patients initially allocated to placebo. Reduced appetite was more frequent with active therapy. No changes in blood pressure or laboratory tests were observed., Limitations: Posthoc analyses and low numbers., Conclusion: Oral roflumilast induced weight loss and reduced appetite, which support the growing evidence of roflumilast as an attractive treatment alternative for patients with psoriasis., Competing Interests: Conflicts of interest Dr Meteran received research funding from ALK-Abelló and honoraria as consultant and/or speaker for ALK-Abelló, GSK, Novartis, AstraZeneca, Sanofi-Aventis Denmark, and Teva. Skov received research funding from Almirall, Bristol-Myers Squibb, AbbVie, Janssen Pharmaceuticals, Sanofi, and the LEO Foundation, and honoraria as consultant and/or speaker for AbbVie, Eli Lilly, Novartis, Pfizer, LEO Pharma, Janssen Cilag, UCB, Almirall, Bristol-Myers Squibb, Boehringer Ingelheim, Novo Nordisk, and Sanofi, and is an investigator for AbbVie, Pfizer, Sanofi, Janssen Cilag, Boehringer Ingelheim, Eli Lilly, Novartis, Galderma, and LEO Pharma. Dr Zachariae is a paid speaker for Eli Lilly, Novartis, CSL, and LEO Pharma and a consultant and/or advisory board member for AbbVie, Janssen Cilag, Novartis, Eli Lilly, LEO Pharma, UCB, Almirall, Takeda, Amgen, Galderma, and CSL. Dr Knop served on scientific advisory panels, has been part of speaker's bureaus, served as a consultant to and/or received research support from 89bio, Amgen, AstraZeneca, Bayer, Boehringer Ingelheim, Carmot Therapeutics, Eli Lilly, Gubra, Lupin, MedImmune, MSD/Merck, Mundipharma, Norgine, Novo Nordisk, Pharmacosmos, Sanofi, Structure Therapeutics, Zealand Pharma, and Zucara, and is a minority shareholder in Antag Therapeutics and co-owner of the weight loss clinic Medicinsk Vægttabsbehandling ApS. Dr Egeberg received research funding from Pfizer, Eli Lilly, Novartis, AbbVie, Boehringer Ingelheim, Almirall, and Janssen Pharmaceuticals, and consultant and/or speaker honoraria from AbbVie, Almirall, Boehringer Ingelheim, Bristol-Myers Squibb, Dermavant, Eli Lilly and Company, Galderma, Galápagos NV, Horizon Therapeutics, Janssen Pharmaceuticals, LEO Pharma, Mylan, Novartis, Pfizer, Samsung Bioepis Co, Ltd, UCB, and Union Therapeutics. Drs Gyldenløve, Sørensen, Fage, and Nielsen have no conflicts of interest to declare., (Copyright © 2024 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

The introduction of biologic agents for the treatment of psoriasis has revolutionized the current treatment landscape, targeting cytokines in the interleukin (IL)-23/IL-17 pathway and demonstrating strong efficacy and safety profiles in clinical trials. These agents however are costly, are associated with a risk of immunogenicity, and require administration by intravenous or subcutaneous injection, limiting their use among patients. Oral therapies, specifically small molecule and microbiome therapeutics, have the potential to be more convenient and cost-effective agents for patients and have been a focus of development in recent years, with few targeted oral medications available for the disease. In this manuscript, we review pipeline oral therapies for psoriasis identified through a search of ClinicalTrials.gov (30 June 2022-1 October 2023). Available preclinical and clinical trial data on each therapeutic agent are discussed. Small molecules under development include tumor necrosis factor inhibitors, IL-23 inhibitors, IL-17 inhibitors, phosphodiesterase-4 inhibitors, Janus kinase inhibitors, A3 adenosine receptor agonists, and sphingosine-1-phosphate receptor 1 agonists, several of which are entering phase III trials. Oral microbials have also demonstrated success in early phase studies. As new oral therapies emerge for the treatment of psoriasis, real-world data and comparative trials are needed to better inform their use among patients.

Background: Alzheimer disease (AD) and depression often cooccur, and inhibition of phosphodiesterase-4 (PDE4) has been shown to ameliorate neurodegenerative illness. Therefore, we explored whether PDE4 inhibitor rolipram might also improve the symptoms of comorbid AD and depression., Methods: APP/PS1/tau mice (10 months old) were treated with or without daily i.p. injections of rolipram for 10 days. The animal groups were compared in behavioral tests related to learning, memory, anxiety, and depression. Neurochemical measures were conducted to explore the underlying mechanism of rolipram., Results: Rolipram attenuated cognitive decline as well as anxiety- and depression-like behaviors. These benefits were attributed at least partly to the downregulation of amyloid-β, Amyloid precursor protein (APP), and Presenilin 1 (PS1); lower tau phosphorylation; greater neuronal survival; and normalized glial cell function following rolipram treatment. In addition, rolipram upregulated B-cell lymphoma-2 (Bcl-2) and downregulated Bcl-2-associated X protein (Bax) to reduce apoptosis; it also downregulated interleukin-1β, interleukin-6, and tumor necrosis factor-α to restrain neuroinflammation. Furthermore, rolipram increased cAMP, PKA, 26S proteasome, EPAC2, and phosphorylation of ERK1/2 while decreasing EPAC1., Conclusions: Rolipram may mitigate cognitive deficits and depression-like behavior by reducing amyloid-β pathology, tau phosphorylation, neuroinflammation, and apoptosis. These effects may be mediated by stimulating cAMP/PKA/26S and cAMP/exchange protein directly activated by cAMP (EPAC)/ERK signaling pathways. This study suggests that PDE4 inhibitor rolipram can be an effective target for treatment of comorbid AD and depression., (Published by Oxford University Press on behalf of CINP 2023.)

Background: Safe and effective long-term topical treatments for atopic dermatitis (AD) remain limited., Objective: In this phase 2a, single-center, intrapatient, and vehicle-controlled study, we examine the mechanism of action of crisaborole 2% ointment, a topical nonsteroidal PDE4 (phosphodiesterase-4) inhibitor, in a proteomic analysis of 40 adults with mild to moderate AD and 20 healthy subjects., Methods: Within the AD cohort, 2 target lesions were randomized in an intrapatient (1:1) manner to double-blind crisaborole/vehicle applied twice daily for 14 days. Punch biopsy specimens were collected for biomarker analysis at baseline from all participants, then from AD patients only at day 8 (optional) and day 15., Results: Compared to the vehicle, crisaborole significantly reversed dysregulation of the overall lesional proteome and of key markers and pathways (eg, Th2, Th17/Th22, and T-cell activation) associated with AD pathogenesis toward both nonlesional and normal skin. Significant clinical correlations were observed with markers associated with nociception and Th2, Th17, and neutrophilic activation., Limitations: Study limitations include predominance of white patients in the cohort, relatively short treatment time, and regimented administration of crisaborole., Conclusion: Our results demonstrate crisaborole-induced normalization of the AD proteome toward a nonlesional molecular phenotype and further support topical PDE4 inhibition in the treatment of mild to moderate AD., Competing Interests: Conflicts of interest Dr Bissonnette is an Advisory Board Member, Consultant, Speaker and/or Investigator for and received honoraria and/or grants from AbbVie, Almirall, Amgen, AnaptysBio, Arcutis, Bausch Health, Boehringer-Ingelheim, Bristol-Myers Squibb, Dermavant, Eli Lilly, Escalier, Janssen, Kyowa Kirin, LEO Pharma, Nimbus, Pfizer, Regeneron, Sienna, and UCB. He is also an employee and shareholder of Innovaderm Research. Dr Guttman-Yassky has served as a consultant for AbbVie, Amgen, Allergan, Asana Bioscience, Celgene, Concert, Dermira, DS Biopharma, Escalier, Galderma, Glenmark, Kyowa Kirin, LEO Pharmaceuticals, Lilly, Mitsubishi Tanabe, Novartis, Pfizer, Regeneron, Sanofi, and Union Therapeutics; a member of advisory boards of Allergan, Asana Bioscience, Celgene, DBV, Dermavant, Dermira, Escalier, Galderma, Glenmark, Kyowa Kirin, LEO Pharma, Lilly, Novartis, Pfizer, Regeneron, and Sanofi; and a recipient of research grants from AbbVie, AnaptysBio, AntibioTx, Asana Bioscience, Boehringer-Ingelheim, Celgene, DBV, Dermavant, DS Biopharma, Galderma, Glenmark, Innovaderm, Janssen Biotech, Kiniska Pharma, LEO Pharmaceuticals, Lilly, Medimmune, Sienna Biopharmaceuticals, Novan, Novartis, Ralexar, Regeneron, Pfizer, UCB, and Union Therapeutics. Dr Pavel is an employee of the Icahn School of Medicine at Mount Sinai and conducts research sponsored by Pfizer. Dr Werth is a full-time employee of and shareholder in Pfizer, Inc. Kim, Duca, Cheng, Carroll, Facheris, Estrada, Cha, Nocka, and Zhang have no conflicts of interest to declare., (Copyright © 2023 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Introduction: New non-steroidal topical agents are needed for the treatment of psoriasis. Roflumilast cream 0.3% is a once daily phosphodiesterase-4 inhibitor that was recently approved by the FDA for the treatment of plaque psoriasis in adolescents and adults. It is indicated for use on all body surfaces including intertriginous areas., Areas Covered: In this review, we summarize the current knowledge about roflumilast cream for the treatment of psoriasis, highlighting its efficacy and safety profile from published clinical trials. Roflumilast's mechanism of action and pharmacokinetic profile are also discussed., Expert Opinion: Positive results were reported across trials with 48% of patients treated with roflumilast achieving an Investigator Global Assessment score of clear or almost clear at 8 weeks in phase III studies. Most adverse events were mild or moderate in severity and few application-site reactions were reported among participants. Unique advantages of the cream are its success in treating intertriginous areas and its ability to reduce symptoms of itch, results of which may significantly improve quality of life for patients. In the future, real-world data and active comparator trials with existing non-steroidal agents are needed to better understand roflumilast's place in the current treatment landscape.

Background: Roflumilast is a targeted inhibitor of phosphodiesterase (PDE)-4 and has been approved for treatment of severe chronic obstructive pulmonary disease for more than a decade. Generic versions are available in the United States. PDE-4 is involved in the psoriasis pathogenesis, but the efficacy and safety of oral roflumilast in patients with psoriasis have not previously been studied., Methods: A company-independent, multicenter, randomized, double-blind, placebo-controlled trial (ClinicalTrials.govNCT04549870). Patients were randomized 1:1 to receive monotherapy with oral roflumilast 500 μg once daily or placebo. At week 12, placebo patients were switched to open-label roflumilast through week 24. The primary endpoint was a 75% or greater reduction from baseline in the psoriasis area and severity index (PASI75) at week 12., Findings: In all, 46 patients were randomized (roflumilast, n = 23; placebo, n = 23). At week 12, significantly more patients in the active arm achieved PASI75 (8 of 23 patients [35%]) vs. placebo (0 of 23 patients [0%], with a difference vs. placebo of 8 [35%] patients, 95% CI: 3 [13%]-13 [57%] patients) (p = 0.014). At week 24, 15 (65%), 10 (44%), 5 (22%), and 2 (9%) of patients treated with roflumilast from week 0 had PASI50, PASI75, PASI90, and PASI100 responses (key secondary endpoints), respectively. The most prevalent, drug-related adverse events in both treatment groups were transient gastrointestinal symptoms, weight-loss, headache, and insomnia. A total of three patients (roflumilast n = 2; placebo, n = 1) discontinued therapy due to adverse events., Interpretation: Oral roflumilast was efficacious and safe in treating moderate-to-severe plaque psoriasis over 24 weeks. With generic versions available, this drug may represent an inexpensive and convenient alternative to established systemic psoriasis treatments., Funding: Financial support was received from Herlev and Gentofte Hospital, University of Copenhagen, and independent grants from private foundations in Denmark. No pharmaceutical company, including the market authorization holder of roflumilast, was involved in the study at any point., Competing Interests: The Danish market authorization holder of roflumilast was informed prior to study initiation but did not provide any financial or in-kind support for the trial. None of the investigators hold any financial interest in the study drug. Mette Gyldenløve: Research funding from the Kgl. Hofbuntmager Aage Bang Foundation, the Danish Psoriasis Foundation, Fonden af familien Kjærsgaard, Sunds, the Simon Spies Foundation, and the CC. Klestrup og hustru Henriette Klestrups Mindelegat. Four-year postdoctoral stipend (2022–26) from Herlev and Gentofte Hospital, University of Copenhagen. Howraman Meteran: Research funding from Per Henriksens Fond, Danish Lung Association, and ALK-Abelló. Honoraria as consultant and/or speaker for ALK-Abelló, GSK, Novartis, AstraZeneca, Sanofi-Aventis Denmark, Airsonett AB, and Teva. Jennifer A. Sørensen: None. Simon Fage: Investigator for AbbVie, Galderma, UCB, Eli Lilly, Novartis, and LEO Pharma. Yiqiu Yao: None. Jesper Lindhardsen: None. Christoffer Nissen: None. Tanja Todberg: Investigator for Novartis, AbbVie, Dr. Wolff, Galderma, and Almirall. Simon F. Thomsen: Research funding from Janssen Pharmaceuticals, LEO Pharma, Novartis, Sanofi and UCB. Honoraria as consultant and/or speaker for Novartis, CSL, Sanofi, Union Therapeutics, LEO Pharma, Pfizer, Sanofi, and AstraZeneca. Lone Skov: Research funding from Almirall, Bristol-Myers Squibb, AbbVie, Janssen Pharmaceuticals, the Danish Psoriasis Foundation, the LEO Foundation, and the Kgl. Hofbundtmager Aage Bang Foundation. Honoraria as consultant and/or speaker for AbbVie, Eli Lilly, Novartis, Pfizer, LEO Pharma, Janssen Cilag, UCB, Almirall, Bristol-Myers Squibb, Boehringer Ingelheim, Novo, and Sanofi. Investigator for AbbVie, Pfizer, Sanofi, Janssen Cilag, Boehringer Ingelheim, Eli Lilly, Novartis, Galderma, and LEO Pharma. Claus Zachariae: Paid speaker for Eli Lilly, Novartis, CSL, and LEO Pharma. Consultant and/or advisory board member for AbbVie, Janssen Cilag, Novartis, Eli Lilly, LEO Pharma, UCB, Almirall, Takeda, Amgen, and CSL. Lars Iversen: Consultant and/or speaker honoraria from AbbVie, BMS, LEO Pharma, Novartis, UCB, Janssen Pharmaceuticals, Boehringer Ingelheim, and Regranion. Part-time employment at MC2 Therapeutics. Mia-Louise Nielsen: None. Alexander Egeberg: Research funding from the Danish Psoriasis Foundation, the Kgl. Hofbuntmager Aage Bang Foundation, the Simon Spies Foundation, Pfizer, Eli Lilly, Novartis, AbbVie, and Janssen Pharmaceuticals. Consultant and/or speaker honoraria from AbbVie, Almirall, Bristol-Myers Squibb, Dermavant, Eli Lilly and Company, Galderma, Galápagos NV, Horizon Therapeutics, Janssen Pharmaceuticals, LEO Pharma, Mylan, Novartis, Pfizer, Samsung Bioepis Co., Ltd., UCB, and Union Therapeutics., (© 2023 Published by Elsevier Ltd.)

Nephrotic syndrome (NS) is associated with kidney dysfunction and is an important cause of morbidity and mortality in industrialized countries. Here, we evaluated the effects of the phosphodiesterase-4 (PDE-4) inhibitors rolipram and roflumilast on a doxorubicin-induced NS model. Early-stage rolipram treatment preserved glomerular filtration barrier function, as indicated by reduced serum protein and albumin loss and the prevention of hypercholesterolemia. These effects were associated with reduced glomerular and tubular lesions and abrogated renal cell apoptosis. In addition, rolipram treatment reduced inflammation, which was characterized by a decrease in macrophage accumulation and reduced levels of CCL2 and TNF in the kidneys. Rolipram also reduced renal fibrosis, which was associated with decreased α-smooth muscle actin (α-SMA) area and increased metalloproteinase 9 (MMP9) activity in renal tissue. Late-stage rolipram or roflumilast treatment preserved glomerular filtration barrier function, as characterized by reduced serum albumin loss, decreased proteinuria, and the prevention of hypercholesterolemia. Importantly, only roflumilast treatment was associated with a reduction in glomerular and tubular lesions at this time point. In addition, both rolipram and roflumilast reduced renal tissue fibrosis and MMP9 activity in renal tissue., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Psoriasis is a multifactorial chronic autoimmune skin disorder, the exact cause of which is still under investigation. It is classified into different types displaying various histopathological features such as hyperproliferation, irregular parakeratosis and vascular infiltration of various immune cells with neutrophils in the epidermis. Over the past few decades, psoriasis pathogenesis has been thoroughly researched, leading to several advances in the treatment using small molecules and biologics. This review focuses on describing the role of various signaling pathways, including PDE-4, JAK-STAT, S1P, A 3 AR and NF-κB, in psoriasis pathogenesis and associated new molecules that are either recently approved or under clinical trials. This study has also addressed the relevance of employing nanotherapeutics to boost the efficacy of psoriasis treatment., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

As our understanding of the pathogenesis of psoriasis has evolved over the past two decades, so has the number of treatment options. The introduction of biologic agents targeting specific cytokines in the interleukin (IL)-23/IL-17 pathway has proven successful in promoting skin clearance among patients. However, their use is often limited owing to cost, parenteral administration, and possible reduced efficacy over time. Topical therapies have also seen limited advancement, with agents such as corticosteroids and vitamin D derivatives remaining the mainstay of treatment, despite side effects limiting their long-term use. New therapeutic agents are needed to improve disease management for patients. In this review, we summarize pipeline and recently approved therapies undergoing clinical trials for psoriasis during a 12-month search period (30 June 2021 to 30 June 2022) using ClinicalTrials.gov. New-generation biologics and oral small molecules in phase II or III development were included, and pivotal data identified through various search modalities (PubMed, conference presentations, etc.) evaluating each drug candidate will be discussed. Topical therapies will also be discussed in line with recent US Food and Drug Administration approvals. As new therapies continue to enter the treatment landscape, long-term data and comparative trials will be needed to better understand their place among existing therapeutic agents., (© 2022. The Author(s).)

Phosphodiesterase-4 (PDE4) is an important drug target for inflammatory diseases. Previously, we identified a series of novel PDE4 inhibitors derived from the natural Toddacoumalone, among which the hit compound 2 with a naphthyridine scaffold showed moderate potency with the IC 50 value of 400 nM. Based on the co-crystal structure of PDE4D-2, further structural optimizations and structure-activity relationship studies led to a highly potent PDE4 inhibitor 23a with the IC 50 value of 0.25 nM and excellent selectivity profiles over other PDEs (>4000-fold). The co-crystal structure of PDE4D-23a elucidated that 23a has strong interactions with the M and Q pocket of PDE4D. Importantly, compound 23a significantly inhibits the release of inflammatory cytokines TNF-α and IL-6 in lipopolysaccharide-stimulated RAW264.7 cells. Thus, compound 23a with a naphthyridine scaffold is a promising PDE4 inhibitor for the treatment of inflammatory diseases., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: The spinal phosphodiesterase-4 (PDE4) plays an important role in chronic pain. Inhibition of PDE4, an enzyme catalyzing the hydrolysis of cyclic adenosine monophosphate AMP (cAMP), produces potent antinociceptive activity. However, the antinociceptive mechanism remains largely unknown. Connexin43 (Cx43), a gap junction protein, has been shown to be involved in controlling pain transduction at the spinal level; restoration of Cx43 expression in spinal astrocytes to the normal levels reduces nerve injury-induced pain. Here, we evaluate the novel mechanisms involving spinal cAMP-Cx43 signaling by which PDE4 inhibitors produce antinociceptive activity., Methods: First, we determined the effect of PDE4 inhibitors rolipram and roflumilast on partial sciatic nerve ligation (PSNL)-induced mechanical hypersensitivity. Next, we observed the role of cAMP-Cx43 signaling in the effect of PDE4 inhibitors on PSNL-induced mechanical hypersensitivity., Results: Single or repeated, intraperitoneal or intrathecal administration of rolipram or roflumilast significantly reduced mechanical hypersensitivity in mice following PSNL. In addition, repeated intrathecal treatment with either of PDE4 inhibitors reduced PSNL-induced downregulation of cAMP and Cx43, and upregulation of proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β. Furthermore, the antinociceptive effects of PDE4 inhibitors were attenuated by the protein kinase A (PKA) inhibitor H89, TNF-α, or Cx43 antagonist carbenoxolone. Finally, PSNL-induced upregulation of PDE4B and PDE4D, especially the PDE4B subtype, was reduced by treatment with either of the PDE4 inhibitors., Conclusions: The results suggest that the antinociceptive effect of PDE4 inhibitors is contributed by increasing Cx43 expression via cAMP-PKA-cytokine signaling in the spinal dorsal horn., (© 2022 The Authors. CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

Purpose/aims: This study focused on delineating the possible effects of roflumilast (ROF), a selective phosphodiesterase 4 (PDE4) inhibitor, in rats with cecal ligation and puncture (CLP)-induced polymicrobial sepsis, and investigated whether ROF can act as a protective agent in sepsis-induced lung damage., Material and Methods: Four experimental groups were organized, each comprising eight rats: Control, Sepsis, Sepsis + ROF 0.5 mgkg -1 , and Sepsis + ROF 1 mgkg -1 groups. A polymicrobial sepsis model was induced in the rats by cecal ligation and puncture under anesthesia. Twelve hours after sepsis induction, the lungs were obtained for biochemical, molecular, and histopathological analyses., Results: In the sepsis group's lungs, the TNF-α, IL-1β, and IL-6 mRNA expression levels peaked in the sepsis group's lung tissues, and ROF significantly decreased these levels compared with the sepsis group dose-dependently. ROF also significantly decreased MDA levels in septic lungs and increased antioxidant parameters (SOD and GSH) compared with the sepsis group. Histopathological analysis results supported biochemical and molecular results., Conclusions: ROF, a PDE4 inhibitor, suppressed the expression levels of pro-inflammatory cytokines, alleviated lung damage (probably by blocking neutrophil infiltration), and increased the capacity of the antioxidant system.

Some evidence has demonstrated that both inflammation and immune cell dysregulation are coincident at late phase (post 24 h) of sepsis. The present study was designed to determine the pathological role of hyperinflammation and renal immune cells mobilization during late phase of sepsis induced acute kidney injury (S-AKI) and tests the pharmacological effects of PDE-4 inhibitor on these events. Sepsis was induced by cecal ligation puncture and renal function, oxidative-inflammatory stress biomarkers were assessed after 24 h. PDE-4 inhibitor was administered for 7 days prior to induction of S-AKI. Renal immune cells infiltration during sepsis was analyzed by H&E staining and papanicolaou staining method was used for detecting leukocytes and cast in urinary sediments, periodic acid schiff (PAS) staining was used for detection of brush border loss. AKI developed 24 h post sepsis insult as depicted by increase in serum creatinine, blood urea nitrogen (BUN), renal oxidative stress, and elevated inflammatory biomarkers levels. Moreover, septic rats displayed increased bacterial load, renal expression of phosphodiesterase-4B, 4D isoforms, enhanced vascular permeability, caspase-3 and myeloperoxidase activity, electrolyte imbalance, reduced Na + K + ATPase activity, declined cAMP levels, increased interstitial leukocyte infiltration, and leakage in urinary sediments along with histological alterations. Pre-treatment with roflumilast at high dose completely prevented the various AKI associated manifestations in septic rats. Renal hyper-inflammation and leukocyte infiltration was detected in late phase of S-AKI. Roflumilast pre-treatment resolved sepsis induced renal dysfunction and histological damage by suppressing late phase renal immune cells invasion and anti-inflammatory effects mediated by up-regulation of renal cAMP levels., (© 2021 Société Française de Pharmacologie et de Thérapeutique.)

The pleiotropic function of 3',5'-cyclic adenosine monophosphate (cAMP)-dependent pathways in health and disease led to the development of pharmacological phosphodiesterase inhibitors (PDE-I) to attenuate cAMP degradation. While there are many isotypes of PDE, a predominant role of PDE4 is to regulate fundamental functions, including endothelial and epithelial barrier stability, modulation of inflammatory responses and cognitive and/or mood functions. This makes the use of PDE4-I an interesting tool for various therapeutic approaches. However, due to the presence of PDE4 in many tissues, there is a significant danger for serious side effects. Based on this, the aim of this review is to provide a comprehensive overview of the approaches and effects of PDE4-I for different therapeutic applications. In summary, despite many obstacles to use of PDE4-I for different therapeutic approaches, the current data warrant future research to utilize the therapeutic potential of phosphodiesterase 4 inhibition.

Prostate cancer chemoresistance is a major therapeutic problem, and the underlying mechanism is not well understood and effective therapies to overcome this problem are not available. Phosphodiesterase-4 (PDE4), a main intracellular enzyme for cAMP hydrolysis, has been previously shown to involve in the early chemo-sensitive prostate cancer cell proliferation and progression, but its role in the more-advanced chemo-resistant prostate cancer is completely unknown. Here we found that the expression of PDE4 subtype, PDE4D, is highly elevated in the chemo-resistant prostate cancer cells (DU145-TxR and PC3-TxR) in comparison to the chemo-sensitive prostate cancer cells (DU145 and PC3). Inhibition of PDE4D with a potent and selective PDED4 inhibitor, Eggmanone, effectively decreases the invasion and proliferation as well as induces cell death of the chemo-resistant prostate cancer cells (DU145-TxR and PC3-TxR). These results were confirmed by siRNA knockdown of PDE4D. We and colleagues previously reported that Eggmanone can effectively blocked sonic Hedgehog signaling via PDE4D inhibition, and here our study suggests that that Eggmanone downregulated proliferation of the chemo-resistant prostate cancer cells via sonic Hedgehog signaling. In addition, Eggmanone treatment dose-dependently increases docetaxel cytotoxicity to DU145-TxR and PC3-TxR. As cancer stem cells (CSCs) are known to be implicated in cancer chemoresistance, we further examined Eggmanone impacts on CSC-like properties in the chemo-resistant prostate cancer cells. Our study shows that Eggmanone effectively down-regulates the expression of CSCs' marker genes Nanog and ABC sub-family G member 2 (ABCG2) and attenuates sphere formation in DU145-TxR and PC3-TxR cells. In summary, our work shows that Eggmanone effectively overcomes the chemoresistance of prostate cancer cells presumably through sonic Hedgehog signaling and targeting CSCs, suggesting that Eggmanone may serve as a novel agent for chemo-resistant prostate cancer.

ATP binding cassette (ABC) transporters are present in all three domains of life - Archaea, Bacteria, and Eukarya. The conserved nature is a testament to the importance of these transporters in regulating endogenous and exogenous substrates required for life to exist. In humans, 49 ABC transporters have been identified to date with broad expression in different lung cell types with multiple transporter family members contributing to lung health and disease. The ABC transporter most commonly known to be linked to lung pathology is ABCC7, also known as cystic fibrosis transmembrane conductance regulator - CFTR. Closely related to the CFTR genomic sequence is ABCC4/multi-drug resistance protein-4. Genomic proximity is shared with physical proximity, with ABCC4 and CFTR physically coupled in cell membrane microenvironments of epithelial cells to orchestrate functional consequences of cyclic-adenosine monophosphate (cAMP)-dependent second messenger signaling and extracellular transport of endogenous and exogenous substrates. The present concise review summarizes the emerging data defining a role of the (ABCC7/CFTR)-ABCC4 macromolecular complex in human airway epithelial cells as a physiologically important pathway capable of impacting endogenous and exogenous mediator transport and ion transport in both lung health and disease., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Phosphodiesterases (PDEs) are a heterogeneous superfamily of enzymes which catalyze the degradation of the intracellular second messengers cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Among PDEs, PDE4 is the most widely studied and characterized isoenzyme. PDE4 blocking can lead to increased levels of intracellular cAMP, which results in down-regulation of inflammatory responses by reducing the expression of tumor necrosis factor (TNF), interleukin (IL)-23, IL-17, interferon-γ, while increasing regulatory cytokines, such as IL-10. Therefore, PDE4 has been explored as a therapeutic target for the treatment of different chronic inflammatory conditions such as psoriatic arthritis (PsA) and inflammatory bowel disease (IBD). PsA shares clinical, genetic, and pathogenic features with IBD such as ulcerative colitis (UC) and Crohn's disease (CD), and enteropathic spondyloarthritis (eSpA) represent a frequent clinical evidence of the overlap between gut and joint diseases. Current therapeutic options in PsA patients and underlying UC are limited to synthetic immunosuppressants and anti-TNF. Apremilast is an oral PDE4 inhibitor approved for the treatment of active PsA patients with inadequate response to synthetic immunosuppressants. The efficacy and a good safety profile observed in randomized clinical trials with apremilast in PsA patients have been confirmed by few studies in a real-life scenario. In addition, apremilast led to significant improvement in clinical and endoscopic features in UC patients in a phase II RCT. By now there are no available data regarding its role in eSpA patients. In view of the above, the use of apremilast in eSpA patients is a route that deserves to be deepened.

McCune-Albright syndrome (MAS) is a mosaic disorder arising from gain-of-function mutations in the GNAS gene, which encodes the 3',5'-cyclic adenosine monophosphate (cAMP) pathway-associated G-protein, G s α. Clinical manifestations of MAS in a given individual, including fibrous dysplasia, are determined by the timing and location of the GNAS mutation during embryogenesis, the tissues involved, and the role of G s α in the affected tissues. The G s α mutation results in dysregulation of the cAMP signaling cascade, leading to upregulation of phosphodiesterase type 4 (PDE4), which catalyzes the hydrolysis of cAMP. Increased cAMP levels have been found in vitro in both animal models of fibrous dysplasia and in cultured cells from individuals with MAS but not in humans with fibrous dysplasia. PET imaging of PDE4 with 11 C-( R )-rolipram has been used successfully to study the in vivo activity of the cAMP cascade. To date, it remains unknown whether fibrous dysplasia and other symptoms of MAS, including neuropsychiatric impairments, are associated with increased PDE4 activity in humans. Methods: 11 C-( R )-rolipram whole-body and brain PET scans were performed on 6 individuals with MAS (3 for brain scans and 6 for whole-body scans) and 9 healthy controls (7 for brain scans and 6 for whole-body scans). Results: 11 C-( R )-rolipram binding correlated with known locations of fibrous dysplasia in the periphery of individuals with MAS; no uptake was observed in the bones of healthy controls. In peripheral organs and the brain, no difference in 11 C-( R )-rolipram uptake was noted between participants with MAS and healthy controls. Conclusion: This study is the first to find evidence for increased cAMP activity in areas of fibrous dysplasia in vivo. No differences in brain uptake between MAS participants and controls were detected-a finding that could be due to several reasons, including the limited anatomic resolution of PET. Nevertheless, the results confirm the usefulness of PET scans with 11 C-( R )-rolipram to indirectly measure increased cAMP pathway activation in human disease., (© 2020 by the Society of Nuclear Medicine and Molecular Imaging.)

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy typically associated with psoriasis (PsO). The pathogenesis is strictly related to the association among the presence of genetic risk alleles and innate and acquired immune response with dramatic consequences on bone remodeling. Clinically, PsA patients may present heterogenicity of articular and periarticular manifestations that may be associated with the presence of comorbidities making treatment decision challenging in patients management. The identification of patient-targeted therapies is still a critical issue. Actually, several biological and synthetic drugs are promising in terms of efficacy and safety profile. National and international treatment recommendations support clinicians in the decision of the best treatment, although they may have limits basically related to updates and different outcomes included in the clinical studies evaluated. The aim of this narrative review is therefore to give guidance for clinicians for PsA patients treatment. For this purpose, we evaluated evidence on biological therapies efficacy used for PsA treatment. Specifically, we reviewed data on biological therapies, Janus kinases (JAK) inhibitors, and drugs with a new mechanism of action that are part of the treatment pipeline. The concept of "switching" and "swapping" is also described, as well as data concerning special populations such as pregnant women and elderly patients., Competing Interests: The authors report no conflicts of interest in this work., (© 2020 Chimenti et al.)

The author provides a thorough review of the latest topical treatment approaches for atopic dermatitis. Some agents are currently available in the marketplace, while others are in development. Modes of action, including phosphodiesterase-4 inhibition, aryl hydrocarbon receptor activation, and Janus kinase inhibition are discussed. Emphasis is placed on therapeutic approaches related to modes of action, with clinical data included., Competing Interests: FUNDING:No funding was provided for this study. DISCLOSURES:Dr. Del Rosso, in relation to this subject area, is an advisor, research investigator, and/or speaker for Almirall, Anaptys Bio, Arcutis, Botanix, Dermavant, Dermira (Lilly), Encore, Galderma, Incyte, La Roche Posay, LEO Pharma, MC2, Menlo Therapeutics, Ortho Dermatologics (Bausch), Pfizer, Ralexar, Regeneron, Sanofi/Genzyme, Sonoma, and Sun Pharma. He is the sole author of this article and has not received any form of compensation related to writing or publishing this article from any pharmaceutical or device company or from any of their affiliated agencies., (Copyright © 2020. Matrix Medical Communications. All rights reserved.)

Introduction: In recent years, different studies regarding psoriatic arthritis (PsA) have shown the pathogenetic role of dysfunction of signaling pathways involving the phosphodiesterase-4 enzyme and transcription factors or enzymes belonging to the kinase (JAK)-signal family pathway. These also represent the target of several drugs known as targeted synthetic disease-modifying antirheumatic drugs (tsDMARDs)., Areas Covered: The authors performed a systematic literature search using the PubMed database, as well as through retrieving data from randomized controlled trials, their post-hoc analysis, and pooled data analysis on the efficacy and safety profile of the PDE4 inhibitor (PDE4i), apremilast, and the inhibitors of JAK (JAKis), tofacitinib, filgotinib, baricitinib, and upadacitinib, in PsA., Expert Opinion: In PsA, the PDE4i, apremilast, and the JAKi, tofacitinib, are effective across multiple clinical domains and have an acceptable tolerability profile, thus expanding the treatment options available for PsA patients. Apremilast and tofacitinib show several advantages mainly represented by their oral administration, a fast onset of action, and a short half-life. Data on tsDMARDs in PsA are still limited, and randomized trials and real-life studies are advocated.

Roflumilast is an inhibitor of phosphodiesterase-4 (PDE4) and can suppress the hydrolysis of cAMP in inflammatory cells, conferring anti-inflammatory effects. This study aimed to investigate the protective effects of roflumilast on hyperoxia-induced acute lung injury (HALI) in a rat model. Male Sprague-Dawley rats were randomly assigned into: control group; HALI group; 2.5 mg/kg roflumilast group; and 5 mg/kg roflumilast group. Rats were pressurized to 250 kPa with pure oxygen to induce lung injury. In the roflumilast groups, rats were orally administered with roflumilast at 2.5 or 5 mg/kg once before hyperoxia exposure and once daily for two days after exposure. Rats were sacrificed 72 hours after hyperoxia exposure. The lung tissues were collected for the detection of lung water content, inflammatory cytokines and NF-κB/p-NF-κB protein expression, and the bronchoalveolar lavage fluid was harvested for the measurement of protein concentration and lactate dehydrogenase activity. Results showed roflumilast at different doses could significantly reduce lung edema, improve lung pathology and reduce the expression of inflammatory cytokines in the lung. The protective effects seemed to be related to the dose of roflumilast. Our study indicates roflumilast has the potential as a medication for the treatment of HALI., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Background: Pulmonary air embolism (PAE)-induced acute lung injury (ALI) can be caused by massive air entry into the lung circulation. PAE can occur during diving, aviation, and some iatrogenic invasive procedures. PAE-induced ALI presents with severe inflammation, hypoxia, and pulmonary hypertension, and it is a serious complication resulting in significant morbidity and mortality. Phosphodiesterase-4 (PDE4) inhibitors can regulate inflammation and are therefore expected to have a therapeutic effect on ALI. However, the effect of the PDE4 inhibitor roflumilast on PAE-induced ALI is unknown., Methods: The PAE model was undertaken in isolated-perfused rat lungs. Four groups (n = 6 in each group) were defined as follows: control, PAE, PAE + roflumilast 2.5 mg/kg, and PAE + roflumilast 5 mg/kg. Induction of PAE-induced ALI was achieved via the infusion of 0.7 cc air through the pulmonary artery. Roflumilast was administered via perfusate. All groups were assessed for pulmonary microvascular permeability, lung histopathology changes, pulmonary edema (lung weight/body weight, lung wet/dry weight ratio), tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-6, IL-17, nuclear factor-kappa B (NF-κB), and inhibitor of NF-κB alpha (IκB-α)., Results: After the induction of air, PAE-induced ALI presented with pulmonary edema, pulmonary microvascular hyperpermeability, and lung inflammation with neutrophilic sequestration. The PAE-induced ALI also presented with increased expressions of IL-1β, IL-6, IL-8, IL-17, TNF-α, and NF-κB and decreased expression of IκB-α. The administration of roflumilast decreased pulmonary edema, inflammation, cytokines, NF-κB, and restored IκB-α level., Conclusions: PAE-induced ALI presents with lung inflammation with neutrophilic sequestration, pulmonary edema, hyperpermeability, increased cytokine levels, and activation of the NF-κB pathway. Roflumilast attenuates lung edema and inflammation and downregulates the NF-κB pathway and cytokines., (Copyright © 2019. Published by Elsevier Inc.)

Background: A novel topical phosphodiesterase-4 inhibitor E6005 shows potential as effective treatment option for atopic dermatitis (AD); however, systemic exposure may cause potentially undesirable adverse reactions. In this study, we evaluated the relationship between the systemic exposure of E6005 and clinical parameters including skin condition and the incidence of AEs in patients with AD. Methods: The association analysis used the clinical data obtained in a previously conducted clinical study with topical E6005 in adult patients with AD. To estimate associations with drug exposure, generalized estimating equation logistic regression models were used, along with clinical data and plasma concentrations of M11, the major metabolite of E6005 (as an indicator for E6005 exposure). Results: The metabolite M11 was detected in 62 of 221 plasma samples from 72 subjects. From association analysis, SCORAD-A obtained prior to E6005 treatment was identified as the clinical parameter influenced to M11 detection with statistical significance ( p  = .003). M11 detection was not clearly associated with the incidence of adverse events occurred. Conclusion: Exposure to topical E6005 is associated with the eczema-associated area, however, that is not distinctly associated with its adverse drug reactions occurred after drug applications possibly due to E6005's characteristics of tissue distribution.

Background: Chronic acrodermatitis continua of Hallopeau (ACH) is a rare form of pustular psoriasis predominantly affecting the distal phalanges of the fingers and toes. The disease manifests by pustular rash with marked infiltration, fissures, and often results into severe dystrophy of nail plates. ACH is refractory to most of psoriasis standard of care (SOC) therapies. Objective: The objective of this study is to assess the prospects of secukinumab therapy of ACH based on current clinical observation. Methods: We observed a female patient with ACH. Number of SOC treatments were applied in that case including local PUVA therapy, systemic retinoids, methotrexate, and biologic agents. Result: Secukinumab, a IL-17 inhibitor, demonstrated pronounced clinical effect in the case of ACH refractory to other SOC therapies. Conclusion: IL-17 inhibition provided by secukinumab was linked to clinically meaningful improvement in the heavily pretreated ACH. Further exploration and clinical studies may be important to provide more data on secukinumab effects in ACH., Competing Interests: The authors report no conflicts of interest in this work.

Many systemic therapies are under development for atopic dermatitis, many of which are injectable monoclonal antibodies that inhibit specific pathways involved in the pathogenesis of the disease. Most are currently under development, however, there are preliminary studies with subcutaneous omalizumab (IgE-directed therapy), and oral apremilast (phosphodiesterase-4 [PDE-4] inhibition. Further studies are needed with these agents. This article discusses various agents that address several potential therapeutic approaches, including IgE-directed therapy, anti-IL-31, anti-IL-5, anti-IL-22, PDE-4 inhibition, and thymic stromal lymphopoietin (TSLP)-directed therapy., Competing Interests: FUNDING:There was no funding related to the development, writing, or publication of this article. DISCLOSURES:Dr. Del Rosso is a consultant, researcher and/or speaker related to this subject area, for Almirall, AnaptysBio, Botanix, Dermavant, Dermira, Galderma, LaRoche Posay, Loreal, Leo Pharma, Pfizer, Ralexar, Regeneron, Sanofi-Genzyme, Valeant.

Phosphodiesterase type 4 (PDE4) inhibitors can prevent the breakdown of the second messenger cyclic adenosine monophosphate (cAMP) and improve cognitive performances in several animal models of cognition. However, the clinical development of PDE4 inhibitors has been seriously hampered by severe side effects, such as vomiting and nausea. In this study, we investigated the effect and mechanism of roflumilast, an FDA-approved PDE4 inhibitor for treatment of chronic obstructive pulmonary disease (COPD), on learning and memory abilities in the APP/PS1 mouse model of Alzheimer's disease (AD). APP/PS1 transgenic mice received 3 intragastric doses of roflumilast (0.1, 0.2 and 0.4 mg/kg) daily for 3 weeks followed by behavioral tests. Chronic administration of roflumilast significantly improved the learning and memory abilities of APP/PS1 transgenic mice in the novel object recognition task, Morris water maze, and the step-down passive avoidance task. In addition, roflumilast increased the cAMP, phosphorylated cAMP response-element binding protein (p-CREB) and brain-derived neurotrophic factor (BDNF) levels, and reduced the nuclear translocation of nuclear factor-kappa B (NF-κB) p65, and proinflammatory cytokine (IL-6, TNF-a and IL-1β) levels in the hippocampus of APP/PS1 transgenic mice. In conclusion, these findings suggest that roflumilast can enhance cognitive function in APP/PS1 transgenic mice, which may be related to its stimulation of the cAMP/CREB/BDNF pathway and anti-neuroinflammatory effects.

Extracorporeal circulation can be accompanied by increased vascular permeability leading to pathological fluid balance and organ dysfunction. The second messenger cAMP is involved in capillary permeability and maintains endothelial integrity. The aim of the present study was to evaluate the effect of phosphodiesterase-4 (PDE4) inhibition with rolipram on extracorporeal circulation-induced capillary leakage, microcirculatory dysfunction, and organ injury in rodents. Rats were randomly allocated to the following groups: sham ( n = 5), venoarterial extracorporeal circulation [extracorporeal life support (ECLS), n = 7], ECLS + rolipram ( n = 7), extracorporeal resuscitation (ECPR; n = 7), and ECPR + rolipram ( n = 7). In the groups that underwent ECPR, ECLS-based cardiopulmonary resuscitation (ECPR) was performed after the induction of hypoxic cardiac arrest. Upon return of spontaneous circulation, rolipram was administered intravenously. The mesenteric microcirculation was studied using intravital microscopy, and organ specimens were harvested upon completion of the study. ECLS and ECPR induced a proinflammatory response (cytokines IL-1β, IL-6, and TNF-α). Although PDE4 expression was upregulated in vascular tissue, PDE4 inhibition abrogated impaired microcirculation and capillary leak (albumin extravasation of the sham group: 1 ± 0.03-fold, ECLS group: 1.2 ± 0.05-fold, ECLS + rolipram group: 0.99 ± 0.04-fold, ECPR group: 1.6 ± 0.04-fold, and ECPR + rolipram group: 1.06 ± 0.02-fold from the sham group, P < 0.05). PDE4 inhibition led to stabilization of vascular cAMP levels but did not affect cytokine levels. Capillary leak was reduced, as demonstrated by the decrease of the systemic biomarkers soluble vascular-endothelial cadherin and activated complement 3. Histological analysis revealed reduced injury to the lungs and kidneys after PDE4 inhibition, with a significant decrease in systemic renal damage markers. Our findings demonstrate that extracorporeal circulation causes an inflammatory reaction associated with decreased vascular cAMP levels, increased vascular permeability, and impaired microcirculation. PDE4 inhibition proved to be capable of reducing these side effects in ECLS and ECPR, leading to reduced microcirculatory, renal, and pulmonary injury. NEW & NOTEWORTHY Various complications are common after extracorporeal circulation. Among these, endothelial injury may cause impaired microcirculation and capillary leak. Here, we report that phosphodiesterase-4 inhibition targeting endothelial cAMP is capable of reducing microvascular complications in a rodent model of extracorporeal resuscitation. Microcirculation and vascular permeability are influenced without targeting extracorporeal circulation-induced inflammation. Thus, pulmonary and renal organ protection may be conferred.

Crisaborole, a topical phosphodiesterase-4 (PDE4) inhibitor, is effective in patients with atopic dermatitis. As systemic PDE4 inhibition has also been used with success in psoriasis, clinical trials are underway to determine the utility of topical PDE4 inhibitors in these patients. However, there is no current literature documenting use of crisaborole for psoriasis. Here, we present two cases in which patients with psoriasis were treated successfully with crisaborole.

Phosphodiesterase-4 (PDE4), mainly present in immune cells, epithelial cells, and brain cells, manifests as an intracellular non-receptor enzyme that modulates inflammation and epithelial integrity. Inhibition of PDE4 is predicted to have diverse effects via the elevation of the level of cyclic adenosine monophosphate (cAMP) and the subsequent regulation of a wide array of genes and proteins. It has been identified that PDE4 is a promising therapeutic target for the treatment of diverse pulmonary, dermatological, and severe neurological diseases. Over the past decades, numerous PDE4 inhibitors have been designed and synthesized, among which roflumilast, apremilast, and crisaborole were approved for the treatment of inflammatory airway diseases, psoriatic arthritis, and atopic dermatitis, respectively. It is regrettable that the dramatic efficacies of a drug are often accompanied by adverse effects, such as nausea, emesis, and gastrointestinal reactions. However, substantial advances have been made to mitigate the adverse effects and obtain better benefit-to-risk ratio. This review highlights the dialectical role of PDE4 in drug discovery and the disquisitive details of certain PDE4 inhibitors to provide an overview of the topics that still need to be addressed in the future.

Phosphodiesterase-4 (PDE4) plays a fundamental role in a range of central nervous system (CNS) insults, however, the role of PDE4 in early brain injury (EBI) after subarachnoid hemorrhage (SAH) remains unclear. The current study was designed to investigate the role of PDE4 in EBI after SAH and explore the potential mechanism. The SAH model in Sprague-Dawley rat was established by endovascular perforation process. Rats were randomly divided into: sham group, SAH?+?vehicle group, SAH?+?rolipram (PDE4 inhibitor) group, SAH?+?rolipram?+?sirtinol (SIRT1 inhibitor) group and SAH?+?rolipram+MK2206 (Akt inhibitor) group. Mortality, SAH grades, neurological function, brain edema, immunofluorescence staining and western blotting were performed. Double fluorescence labeling staining indicated that PDE4 was located predominately in neurons after SAH. Rolipram reduced brain edema, improved neurological function in the rat model of SAH. Moreover, rolipram increased the expression of Sirtuin1 (SIRT1) and up-regulated the phosphorylation of Akt, which was accompanied by the reduction of neuronal apoptosis. Administration of sirtinol inhibited the phosphorylation of Akt. Moreover, all the beneficial effects of rolipram against SAH were abolished by both sirtinol and MK2206. These data indicated that PDE4 inhibition by rolipram protected rats against EBI after SAH via suppressing neuronal apoptosis through the SIRT1/Akt pathway. Rolipram might be an important therapeutic drug for SAH., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Selective inhibition of phosphodiesterase (PDE) 4B favorably suppresses the synthesis of inflammatory cytokines and subsequently arrest the development of atopic dermatitis via modulating the intracellular cAMP levels. Considering the side effects of corticosteroids, selective PDE4 inhibition could constitute an effective alternative therapy for the treatment of atopic dermatitis (AD). In this study, a series of novel catechol based compounds bearing pyrimidine as the core have been synthesized and screened for the PDE4 inhibitory properties. The PDE4 selectivity of the active compounds over other PDEs has been investigated. Compound 23 bearing pyrimidine core functionalized with catechol, pyridine and trifluoromethyl groups can effectively inhibit the PDE4B with IC 50 value in nanomolar range (IC 50  = 15 ± 0.4 nM). Compound 23 exhibited seven fold higher selectivity towards PDE4B over PDE4D. Molecular Docking study confirmed its stronger affinity towards catalytic domain of PDE4B. In-vivo analysis confirmed that compound 23 effectively alleviated the symptoms of atopic dermatitis in DNCB-treated Balb/c mice by suppressing the synthesis of inflammatory mediators such as TNF-α, and Ig-E. Taken together, this study suggested that compound 23 could be an effective PDE4 inhibitor for the potential treatment of AD., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Background: Long-term topical treatment is often required for atopic dermatitis (AD), a chronic inflammatory skin disease., Objective: To assess the long-term safety results from a multicenter, open-label, 48-week safety study (AD-303) of patients (N = 517) ≥2 years of age with mild to moderate AD who continued crisaborole treatment, a topical phosphodiesterase-4 inhibitor, after completing a 28-day phase 3 pivotal study (AD-301, AD-302)., Methods: Global disease severity was assessed in patients every 4 weeks, and if assessed as mild or greater, a 28-day treatment period with crisaborole applied twice daily was initiated. Adverse events (AEs), including treatment-emergent AEs (TEAEs), and serious AEs were analyzed., Results: During the pivotal studies and AD-303, 65% of patients reported ≥1 TEAE, most of which were mild (51.2%) or moderate (44.6%) and considered unrelated to treatment (93.1%). The frequency and severity of TEAEs were consistent. The most frequently reported treatment-related AEs (overall, 10.2%) were dermatitis atopic (3.1%), application-site pain (2.3%), and application-site infection (1.2%). Nine patients (1.7%) discontinued the long-term study because of TEAEs., Limitations: Long-term efficacy was not analyzed., Conclusion: Crisaborole ointment had a low frequency of treatment-related AEs over 48 weeks of treatment of patients with AD., (Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Combination therapy of PDE4 inhibitors and anticholinergics induces bronchoprotection in COPD. Mechanical forces that arise during bronchoconstriction may contribute to airway remodeling. Therefore, we investigated the impact of PDE4 inhibitors and anticholinergics on bronchoconstriction-induced remodeling. Because of the different mechanism of action of PDE4 inhibitors and anticholinergics, we hypothesized functional interactions of these two drug classes. Guinea pig precision-cut lung slices were preincubated with the PDE4 inhibitors CHF-6001 or roflumilast and/or the anticholinergics tiotropium or glycopyorrolate, followed by stimulation with methacholine (10 μM) or TGF-β 1 (2 ng/ml) for 48 h. The inhibitory effects on airway smooth muscle remodeling, airway contraction, and TGF-β release were investigated. Methacholine-induced protein expression of smooth muscle-myosin was fully inhibited by CHF-6001 (0.3-100 nM), whereas roflumilast (1 µM) had smaller effects. Tiotropium and glycopyrrolate fully inhibited methacholine-induced airway remodeling (0.1-30 nM). The combination of CHF-6001 and tiotropium or glycopyrrolate, in concentrations partially effective by themselves, fully inhibited methacholine-induced remodeling in combination. CHF-6001 did not affect airway closure and had limited effects on TGF-β 1 -induced remodeling, but rather, it inhibited methacholine-induced TGF-β release. The PDE4 inhibitor CHF-6001, and to a lesser extent roflumilast, and the LAMAs tiotropium and glycopyrrolate inhibit bronchoconstriction-induced remodeling. The combination of CHF-6001 and anticholinergics was more effective than the individual compounds. This cooperativity might be explained by the distinct mechanisms of action inhibiting TGF-β release and bronchoconstriction., (Copyright © 2017 the American Physiological Society.)

Phosphodiesterase-4 (PDE4) is an important drug target for treatment of inflammation-related diseases. Till now, natural PDE4 inhibitors are rare and their co-crystal structures with PDE4 are hardly available. In the present study, selaginpulvilins K and L (1 and 2), two novel fluorene derivatives, were isolated from a traditional Chinese medicine Selaginella pulvinata and exhibited remarkable inhibition against phosphodiesterase-4D (PDE4D) at IC 50 11nM and 90nM, respectively. Compound 1 also showed a good selectivity across PDE families with the selective fold ranging from 30 to 909. To understand the recognition mechanism of selaginpulvilins towards PDE4, the crystal structure of PDE4D bound with 1 was successfully determined by the X-ray diffraction method and presented an unusual binding mode in which the stretched skeleton of the inhibitor bound shallowly to the active site but had interactions with multi sub-pockets, such as Q, HC, M, and S, especially strong interaction with the metal region. Assisted with molecular modeling, the structure-activity relationship and the selectivity of selaginpulvilins were also well explored, which would facilitate the future rational inhibitor design or structural optimizations., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Postoperative cognitive dysfunction (POCD) is characterized by cognitive impairments in patients after surgery. Hippocampal neuroinflammation induced by surgery is highly associated with POCD. Phosphodiesterase-4 (PDE4) is an enzyme that specifically hydrolyses cyclic adenosine monophosphate (cAMP), which plays an important role during neuroinflammation and the process of learning and memory. However, the role of PDE4 in the development of POCD remains unclear. Male 14-month-old C57BL/6 mice received carotid artery exposure to mimic POCD. First, we evaluated cognitive performance by a Morris water maze (MWM) and fear conditioning system (FCS) test after surgery. The expression of PDE4 subtypes, pro-inflammatory cytokines, p-CREB and PSD95 as well as cAMP levels were investigated. Then, we used rolipram, a PDE4 inhibitor, to block the effects of PDE4. The cognitive performance of the mice and the expression of PDE4 subtypes, pro-inflammatory cytokines, p-CREB and PSD95 as well as cAMP levels were examined again. Mice displayed learning and memory impairment, overexpression of PDE4B and PDE4D, elevation of pro-inflammatory cytokines, and reduction in the expression of p-CREB, PSD95 and cAMP levels after surgery. The expression of PDE4B and PDE4D in the hippocampus decreased following blocking of PDE4 by rolipram. Meanwhile, rolipram attenuated the cognitive impairment and the elevation of pro-inflammatory cytokines induced by surgery. Moreover, rolipram reversed the reduction of p-CREB and PSD95. These results indicate that PDE4 subtype overexpression may be involved in the development of surgery-induced cognitive dysfunction in mice., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Thus far, phosphodiesterase-4 (PDE4) inhibitors have not been approved for application in Alzheimer's disease (AD) in a clinical setting due to severe side effects, such as nausea and vomiting. In this study, we investigated the effect of FFPM, a novel PDE4 inhibitor, on learning and memory abilities, as well as the underlying mechanism in the APP/PS1 mouse model of AD. Pharmacokinetic studies have revealed that FFPM efficiently permeates into the brain, and reached peak values in plasma 2 h after orally dosing. A 3-week treatment with FFPM, at doses of 0.25 mg/kg and 0.5 mg/kg, significantly improved the learning and memory abilities of APP/PS1 transgenic mice in the Morris water maze and the Step-down passive avoidance task. Interestingly, we found that while rolipram (0.5 mg/kg) reduced the duration of the α2 adrenergic receptor-mediated anesthesia induced by xylazine/ketamine, FFPM (0.5 mg/kg) or the vehicle did not have an evident effect. FFPM increased the cAMP, PKA and CREB phosphorylation and BDNF levels, and reduced the NF-κB p65, iNOS, TNF-α and IL-1β levels in the hippocampi of APP/PS1 trangenic mice, as observed by ELISA and Western blot analysis. Taken together, our data demonstrated that the reversal effect of FFPM on cognitive deficits in APP/PS1 transgenic mice might be related to stimulation of the cAMP/PKA/CREB/BDNF pathway and anti-inflammatory effects. Moreover, FFPM appears to have potential as an effective PDE4 inhibitor in AD treatment with little emetic potential., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

People in modern, affluent societies are living longer but also becoming increasingly overweight. With increased life expectancy comes increased risk of developing age-related cognitive decline and neurodegenerative diseases, such that an increasing proportion of life may be lived with cognitive impairment as age increases. Obesity is associated with poorer cognitive function in elderly subjects, and often leads to ill-health arising from various complications such as metabolic syndrome and type-2 diabetes mellitus. This chapter provides an overview of the effects of administering pan-phosphodiesterase-4 (PDE4) inhibitors to animal models of cognitive ageing, Alzheimer's disease, frontotemporal dementia, fragile X syndrome, obesity and diabetes. Inhibition of the PDE4B subtype specifically is discussed as an approach to avoid the emetic side effects of pan-PDE4 inhibitors, whilst retaining their therapeutic effects. Finally, the findings of rodent studies that employ genetic and pharmacological approaches to specifically target PDE4B are discussed in relation to the potential utility of PDE4B-selective inhibitors for the treatment of cognitive impairment and obesity-related metabolic diseases.

PsA is an immune-mediated chronic inflammatory disease that affects both skin and joints; it is a heterogeneous disease characterized by synovitis, enthesitis, dactylitis and spondylitis. The impact on patients and the burden of disease are substantial. For assessment of the disease, patient-reported outcomes are increasingly important. Conventional therapy consists of NSAIDs, local and systemic CSs, and synthetic and biological DMARDs. While MTX, LEF, SSZ and CYC are the synthetic drugs mainly used, TNF-α blocking agents have represented the majority of biologics used in the last decade (infliximab, etanercept, adalimumab, certolizumab and golimumab). Treat-to-target strategies have been used successfully in PsA. This review concentrates on new developments, mainly covering biologic agents with an IL-17 inhibitor (secukinumab) and an anti-IL-23 agent (ustekinumab), but also synthetic drugs, including a novel phosphodiesterase-4 inhibitor (apremilast) and a Janus kinase inhibitor (tofacitinib) that blocks mainly Jak3 and Jak1 and, to a lesser extent, Jak2. The efficacy of some of these new agents may be even better for the skin than for the joints., (© The Author 2016. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Uterine relaxation is crucial during preterm labor. Phosphodiesterase-4 (PDE-4) inhibitors have been proposed as tocolytics. Some thalidomide analogs are PDE-4 inhibitors. The aim of this study was to assess the uterus-relaxant properties of two thalidomide analogs, methyl 3-(4-nitrophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4NO2PDPMe) and methyl 3-(4-aminophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4APDPMe) and were compared to rolipram in functional studies of spontaneous phasic, K⁺-induced tonic, and Ca 2+ -induced contractions in isolated pregnant human myometrial tissues. The accumulation of cAMP was quantified in HeLa cells. The presence of PDE-4B2 and phosphorylated myosin light-chain (pMLC), in addition to the effect of thalidomide analogs on oxytocin-induced pMLC, were assessed in human uterine myometrial cells (UtSMCs). Thalidomide analogs had concentration-dependent inhibitory effects on spontaneous and tonic contractions and inhibited Ca 2+ -induced responses. Tonic contraction was equipotently inhibited by 4APDPMe and rolipram (IC 50 = 125 ± 13.72 and 98.45 ± 8.86 µM, respectively). Rolipram and the thalidomide analogs inhibited spontaneous and tonic contractions equieffectively. Both analogs increased cAMP accumulation in a concentration-dependent manner ( p < 0.05) and induced changes in the subcellular localization of oxytocin-induced pMLC in UtSMCs. The inhibitory effects of thalidomide analogs on the contractions of pregnant human myometrium tissue may be due to their PDE-4 inhibitory effect and novel mechanism as calcium-channel blockers.

Background: Roflumilast, a once-daily, selective phosphodiesterase-4 inhibitor, reduces the risk of COPD exacerbations in patients with severe COPD associated with chronic bronchitis and a history of exacerbations. The RE(2)SPOND study is examining whether roflumilast, when added to an inhaled corticosteroid/long-acting β2-agonist (ICS/LABA) fixed-dose combination (FDC), further reduces exacerbations. The methodology is described herein., Methods: In this Phase IV, multicenter, double-blind, placebo-controlled, parallel-group trial, participants were randomized 1:1 (stratified by long-acting muscarinic antagonist use) to receive roflumilast or placebo, plus ICS/LABA FDC, for 52 weeks. Eligible participants had severe COPD associated with chronic bronchitis, had two or more moderate-severe exacerbations within 12 months, and were receiving ICS/LABA FDC for ≥3 months. The primary efficacy measure is the rate of moderate or severe COPD exacerbations per participant per year. The secondary efficacy outcomes include mean change in prebronchodilator forced expiratory volume in 1 second (FEV1) over 52 weeks, rate of severe exacerbations, and rate of moderate, severe, or antibiotic-treated exacerbations. Additional assessments include spirometry, rescue medication use, the COPD assessment test, daily symptoms using the EXACT-Respiratory symptoms (E-RS) questionnaire, all-cause and COPD-related hospitalizations, and safety and pharmacokinetic measures., Results: Across 17 countries, 2,354 participants were randomized from September 2011 to October 2014. Enrollment goal was met in October 2014, and study completion occurred in June 2016., Conclusion: This study will further characterize the effects of roflumilast added to ICS/LABA on exacerbation rates, lung function, and health of severe-very severe COPD participants at risk of further exacerbations. The results will determine the clinical benefits of roflumilast combined with standard-of-care inhaled COPD treatment.

Phosphodiesterase-4 (PDE4) inhibitors prevent the breakdown of the second messenger cAMP and have been demonstrated to improve learning in several animal models of cognition. In this study, we explored the antioxidative effects of rolipram in Alzheimer's disease (AD) by using bilateral Aβ25-35 injection into the hippocampus of rats, which were used as an AD model. Rats received 3 intraperitoneal (i.p.) doses of rolipram (0.1, 0.5 and 1.25 mg/kg) daily after the injection of Aβ25-35 for 25 days. Chronic administration of rolipram prevented the memory impairments induced by Aβ25-35, as assessed using the passive avoidance test and the Morris water maze test. Furthermore, rolipram significantly reduced the oxidative stress induced by Aβ25-35, as evidenced by the decrease in the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and restored the reduced GSH levels and superoxide dismutase (SOD) activity. Moreover, western blotting and real-time reverse transcription polymerase chain reaction (RT-PCR) analysis showed that rolipram remarkably upregulated thioredoxin (Trx) and inhibited the inducible nitric oxide synthase/nitric oxide (iNOS/NO) pathway in the hippocampus. These results demonstrated that rolipram improved the learning and memory abilities in an Aβ25-35-induced AD rat model. The mechanism underlying these effects may be due to the noticeable antioxidative effects of rolipram.

Pneumococcal pneumonia is a leading cause of mortality worldwide. The inflammatory response to bacteria is necessary to control infection, but it may also contribute to tissue damage. Phosphodiesterase-4 inhibitors, such as rolipram (ROL), effectively reduce inflammation. Here, we examined the impact of ROL in a pneumococcal pneumonia murine model. Mice were infected intranasally with 10(5)-10(6) CFU of Streptococcus pneumoniae, treated with ROL in a prophylactic or therapeutic schedule in combination, or not, with the antibiotic ceftriaxone. Inflammation and bacteria counts were assessed, and ex vivo phagocytosis assays were performed. ROL treatment during S. pneumoniae infection decreased neutrophil recruitment into lungs and airways and reduced lung injury. Prophylactic ROL treatment also decreased cytokine levels in the airways. Although modulation of inflammation by ROL ameliorated pneumonia, bacteria burden was not reduced. On the other hand, antibiotic therapy reduced bacteria without reducing neutrophil infiltration, cytokine level, or lung injury. Combined ROL and ceftriaxone treatment decreased lethality rates and was more efficient in reducing inflammation, by increasing proresolving protein annexin A1 (AnxA1) expression, and bacterial burden by enhancing phagocytosis. Lack of AnxA1 increased inflammation and lethality induced by pneumococcal infection. These data show that immunomodulatory effects of phosphodiesterase-4 inhibitors are useful during severe pneumococcal pneumonia and suggest their potential benefit as adjunctive therapy during infectious diseases.

Phosphodiesterase-4 (PDE4) is an anti-inflammatory target for treatment of asthma and chronic obstructive pulmonary disease (COPD). Here, we report the isolation and characterization of 13 compounds (G1-G13) by bioassay-guided fractionation of the ethyl acetate extraction of Gaultheria yunnanensis (FRANCH.), one of which pentacyclic triterpene (G1) has never been reported. Four of them (G1, G2, G4, and G5) inhibit PDE4 with the IC50 values < 20 μM and G1 is the most potent ingredient with an IC50 of 245 nM and moderate selectivity over other PDE families. Molecular dynamics simulations suggest that G1 forms a hydrogen bond with Asn362, in addition to the hydrogen bond with Gln369 and π-π interactions with Phe372, which are commonly observed in the binding of most PDE4 inhibitors. The calculated binding free energies for the interactions of PDE4-G1 and PDE4-G2 are -19.4 and -18.8 kcal/mol, in consistence with the bioassay that G1 and G2 have IC50 of 245 nM and 542 nM, respectively. The modelling results of these active compounds may aid the rational design of novel PDE4 inhibitors as anti-inflammatory agents., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Phosphodiesterase-4 (PDE4) hydrolyses cyclic adenosine monophosphate (cAMP), a crucial secondary messenger for cellular adaptation to diverse external stimuli. The activity of PDE4 is tightly controlled by post-translational regulation, structure-based auto-regulation and locus specific 'compartmentalization' of PDE4 with its interactive proteins (signalsomes). Through these mechanisms, PDE4 regulates cAMP levels and shapes the cAMP signalling, directing signals from the diverse external stimuli to distinct microenvironments exquisitely. Derangement of the PDE4-cAMP signalling represents a pathophysiologically relevant pathway in metabolic disorders as demonstrated through a critical role in the processes including inflammation, disordered glucose and lipid metabolism, hepatic steatosis, abnormal lipolysis, suppressed thermogenic function and deranged neuroendocrine functions. A limited number of PDE4 inhibitors are currently undergoing clinical evaluation for treating disorders such as type 2 diabetes and non-alcoholic steatohepatitis. The discovery of novel PDE4 allosteric inhibitors and signalsome-based strategies targeting individual PDE4 variants may allow PDE4 isoform selective inhibition, which may offer safer strategies for chronic treatment of metabolic disorders., (© 2016 World Obesity.)

cAMP response element binding protein (CREB) signaling is involved in the heroin reward, but whether the CREB signaling is involved in the incubation of heroin-seeking remains unknown. Here we aim to explore the expression of p-CREB and the p-ERK, an upstream molecular of CREB, in the nucleus accumbens (NAc) in the incubation of heroin-seeking induced by cue after withdrawal. First, rats were trained to self-administer heroin for 14 days, and then assessed heroin-seeking induced by context cue (CC)or by conditioned cues (CS)after 1 or 14 d withdrawal. We found that the active responses induced by CC or CS was higher after 14 d withdrawal than that after 1 d withdrawal, and the extent increased was more significant by CS than that by CC. Meanwhile, the expression of p-ERK decreased significantly when rats exposed to the CS, and decreased more after 14 d withdrawal. In contrast, reduction of the expression of p-CREB was more obvious with exposure to CS after 14 d withdrawal. Furthermore, microinjection of rolipram into the NAc decreased the heroin-seeking behavior induced by CS after 14 d withdrawal, which was correlated to an enhancement in the expression of p-CREB in the NAc. These findings suggest that the inactivation of CREB and ERK may be involved in the incubation of heroin-seeking induced by cues after prolonged withdrawal., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Advances in molecular biology have provided the basis for development of new therapeutic approaches to psoriasis. New, more effective therapies target specific molecules in the inflammatory cascade involved in the pathogenesis of psoriasis.The biologic era of psoriasis therapy began with inhibitors of T-cell activation, tumor necrosis factor-α, and interleukin (IL)-12/23. Continued investigation has led to therapies and therapeutic candidates that target IL-17, IL-23, phosphodiesterase-4, and isomers of Janus kinase., (2014 by Frontline Medical Communications Inc.)

The phosphodiesterase-4 (PDE4) enzyme is a promising therapeutic target for several diseases. Our previous studies found resveratrol and moracin M to be natural PDE4 inhibitors. In the present study, three natural resveratrol analogs [pterostilbene, (E)-2',3,5',5-tetrahydroxystilbene (THSB), and oxyresveratrol] are structurally related to resveratrol and moracin M, but their inhibition and mechanism against PDE4 are still unclear. A combined method consisting of molecular docking, molecular dynamics (MD) simulations, binding free energy, and bioassay was performed to better understand their inhibitory mechanism. The binding pattern of pterostilbene demonstrates that it involves hydrophobic/aromatic interactions with Phe340 and Phe372, and forms hydrogen bond(s) with His160 and Gln369 in the active site pocket. The present work also reveals that oxyresveratrol and THSB can bind to PDE4D and exhibits less negative predicted binding free energies than pterostilbene, which was qualitatively validated by bioassay (IC50=96.6, 36.1, and 27.0μM, respectively). Additionally, a linear correlation (R(2)=0.953) is achieved for five PDE4D/ligand complexes between the predicted binding free energies and the experimental counterparts approximately estimated from their IC50 values (≈RT ln IC50). Our results imply that hydrophobic/aromatic forces are the primary factors in explaining the mechanism of inhibition by the three products. Results of the study help to understand the inhibitory mechanism of the three natural products, and thus help the discovery of novel PDE4 inhibitors from resveratrol, moracin M, and other natural products., (© 2013.)

Clinical stimulation of preterm infant breathing with methylxanthines like caffeine and theophylline can evoke seizures. It is unknown whether underlying neuronal hyperexcitability involves the rhythmogenic inspiratory active pre-Bötzinger complex (preBötC) in the brainstem or preBötC-driven motor networks. Inspiratory-related preBötC interneuronal plus spinal (cervical/phrenic) or cranial hypoglossal (XII) motoneuronal bursting was studied in newborn rat en bloc brainstem-spinal cords and brainstem slices, respectively. Non-respiratory bursting perturbed inspiratory cervical nerve activity in en bloc models at >0.25mM theophylline or caffeine. Rhythm in the exposed preBötC of transected en bloc preparations was less perturbed by 10mM theophylline than cervical root bursting which was more affected than phrenic nerve activity. In the preBötC of slices, even 10mM methylxanthine did not evoke seizure-like bursting whereas >1mM masked XII rhythm via large amplitude 1-10Hz oscillations. Blocking A-type γ-aminobutyric (GABAA) receptors evoked seizure-like cervical activity whereas in slices neither XII nor preBötC rhythm was disrupted. Methylxanthines (2.5-10mM), but not blockade of adenosine receptors, phosphodiesterase-4 or the sarcoplasmatic/endoplasmatic reticulum ATPase countered inspiratory depression by muscimol-evoked GABAA receptor activation that was associated with a hyperpolarization and input resistance decrease silencing preBötC neurons in slices. The latter blockers did neither affect preBötC or cranial/spinal motor network bursting nor evoke seizure-like activity or mask corresponding methylxanthine-evoked discharges. Our findings show that methylxanthine-evoked hyperexcitability originates from motor networks, leaving preBötC activity largely unaffected, and suggest that GABAA receptors contribute to methylxanthine-evoked seizure-like perturbation of spinal motoneurons whereas non-respiratory XII motoneuron oscillations are of different origin., (Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.)