Search Results (67)

Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disorder characterized by immune dysregulation and epidermal barrier dysfunction. Advances in understanding the interplay of genetic predisposition, cytokine signaling, and environmental triggers have led to the emergence of targeted therapies. Although biologic agents such as dupilumab, tralokinumab, and lebrikizumab have revolutionized AD management, their high costs, injectable administration, and limited global accessibility highlight the need for alternative options. Small molecule therapies are gaining momentum as they target intracellular pathways central to AD pathogenesis and offer oral or topical administration routes. This review provides a comprehensive analysis of key agents including Janus kinase (JAK) inhibitors (upadacitinib, abrocitinib, baricitinib, ruxolitinib, delgocitinib), phosphodiesterase 4 (PDE4) inhibitors (crisaborole, difamilast, roflumilast, apremilast), as well as STAT6 degraders (KT621, NX3911), aryl hydrocarbon receptor modulators, histamine H4 receptor antagonists (adriforant, izuforant), and sphingosine-1-phosphate receptor modulators (etrasimod, BMS-986166). We summarize their mechanisms of action, pharmacological profiles, and pivotal clinical trial data, emphasizing their potential to address unmet therapeutic needs. Finally, we discuss safety concerns, long-term tolerability, and future directions for integrating small molecule therapies into precision treatment strategies for moderate-to-severe AD. Full article

We report here two new series of designed PDE4 inhibitors, the first one showing the quinoline scaffold recently investigated by us through a fragment-based drug design strategy, and the second consisting of pyrazolo [1′,5′:1,6]pyrimido[4,5-d]pyridazine derivatives. Both the new series were subjected to biological studies to assess their inhibitory effect on PDE4 enzymes, supported by molecular modelling experiments, to rationalize the different activities recorded in the in vitro tests. Interesting results were achieved for two compounds belonging to the tricyclic series, namely 10a and 10e, exhibiting IC₅₀ = 62 and 175.5 nM, respectively. These results could represent the starting point for further studies with the aim of developing new and effective PDE4 inhibitors for biomedical investigations. Full article

Background: Signaling pathways like those depending on cAMP/PKA, calcium/calmodulin/CaMK, MEK-1/MAPK or PI3K/Akt have been described to modulate suprachiasmatic nucleus (SCN) neuronal signaling via influencing transcription factors like CREB. Here, we analyzed the effect of cyclic nucleotide phosphodiesterase inhibitors and structurally similar substances commonly used as autophagy modulators on a cell line stably expressing a cyclic nucleotide element-driven luciferase reporter. Methods: We used an SCN cell line stably transfected with a CRE-luciferase reporter (SCNCRE) to evaluate signaling and vitality responses to various isoform-selective PDE inhibitors and autophagy modulators to evaluate the mechanism of action of the latter. Results: In this study the different impacts of common PDE inhibitors and autophagy modulators on CRE-luciferase activity applied alone and in combination with known CRE-luciferase activating agents showed that (1) PDE3, 4 and 5 are present in SCNCRE cells, with (2) PDE3 being the most active and (3) the autophagy inhibitor 3-Methyladenin (3-MA) displaying PDE inhibitor-like behavior. Conclusions: Experiments provide evidence that, in addition to the extracellular signaling pathways components shown before to be involved in CRE-luciferase activity regulation like cAMP analogs, adenylate cyclase activators and beta-adrenoceptor agonists, cyclic nucleotide metabolism as realized by phosphodiesterase activity, or molecule/agents influencing processes like autophagy or inflammation, modulate transcriptional CRE-dependent activity in these cells. Specifically, we provide evidence that the autophagy inhibitor 3-MA, given that PDEs are expressed, may also act as a PDE inhibitor and inducer of CRE-mediated transcriptional activity. Full article

Background: The European League Against Rheumatism (EULAR), in collaboration with the European Scleroderma Trial and Research group (EUSTAR), published the first set of treatment recommendations for systemic sclerosis (SSc) in 2009, with subsequent updates in 2016 and 2023. Objectives: This study aimed to evaluate how rheumatologists’ clinical approaches to the treatment of SSc evolved following the 2016 update of the clinical management guidelines. Methods: Medication use for SSc was analyzed in a cohort of 378 patients. The patients were stratified based on enrollment before (233 patients) and after (145 patients) the guideline update, and medication usage was compared between the two groups. Results: Although all patients presented with Raynaud’s phenomenon (RP), only 35% received calcium channel blockers. Medications such as iloprost, phosphodiesterase type 5 (PDE-5) inhibitors, fluoxetine, and bosentan, recommended for the treatment of RP and digital ulcers, were not approved for SSc by the Republic Health Insurance Fund. Treatment for pulmonary arterial hypertension (PAH) was administered to only 16 patients (4.2%), including 2 who received bosentan, 10 who received PDE-5 inhibitors, and 4 who were treated with riociguat. The use of PDE-5 inhibitors increased following the 2016 update of the guidelines. Cyclophosphamide was consistently prescribed for interstitial lung disease (ILD), with an increased frequency observed after the guideline update. No significant differences were observed in the use of methotrexate for skin involvement, ACE inhibitors for scleroderma renal crisis, or antibiotics for gastrointestinal symptoms. Proton pump inhibitors (PPIs) were prescribed to 87.3% of patients with gastrointestinal involvement, with an increase in use of both PPIs and prokinetic agents following the guideline update. Conclusions: Rheumatologists’ adherence to the EULAR/EUSTAR guidelines varied considerably, with 25% to 100% of eligible patients receiving the recommended treatments. Concordance improved in the management of PAH, ILD, and gastrointestinal involvement after the 2016 guideline update. Full article

In endothelial cells, high-dose irradiation induces numerous dysfunctions including alteration in junctional proteins such as VE-Cadherin, apoptosis and enhanced adhesiveness linked to overexpression of adhesion molecules like Intercellular Adhesion Molecule 1 (ICAM-1). Such endothelial dysfunctions can lead to altered tissue perfusion, development of tissue inflammation through increased endothelial permeability, and ultimately organ damage. As intracellular cyclic AMP (cAMP) levels are known to control intercellular junctions or apoptosis in the endothelium, we investigated here the effect of the Phosphodiesterase 4 inhibitor Roflumilast, a drug increasing cAMP levels, on irradiation-induced endothelial dysfunctions in human pulmonary microvascular endothelial cells (HPMECs). Using continuous impedance measurements in confluent endothelial cell monolayers, Roflumilast was found to rapidly reinforce the endothelial barrier and to prevent irradiation-induced barrier disruption. In accordance, irradiation-induced alteration in membrane VE-Cadherin-composed adherens junctions was prevented by Roflumilast treatment after irradiation, which was correlated with its protective effect of the actin cytoskeleton. Post-irradiation treatment with Roflumilast also protected HPMECs from irradiation-induced late apoptosis, but was without effect on irradiation-induced ICAM-1 overexpression. Overall, our results indicate that the beneficial effects of Roflumilast after irradiation are linked to the strengthening/protection of the endothelial barrier and reduced apoptosis, suggesting that this medicine may be useful for the treatment of endothelial damages after exposure to a high dose of radiation. Full article

Phosphodiesterase 4 (PDE4) serves as a crucial regulator of cyclic adenosine monophosphate (cAMP) signaling and has been identified as a significant therapeutic target for inflammatory and metabolic disorders impacting the gastrointestinal (GI) tract and liver. Although pan-PDE4 inhibitors hold therapeutic promise, their clinical use has been constrained by dose-dependent adverse effects. Recent progress in the development of isoform-specific PDE4 inhibitors, such as those selective for PDE4B/D, alongside targeted delivery systems like liver-targeting nanoparticles and probiotic-derived vesicles, is reshaping the therapeutic landscape. This review consolidates the latest insights into PDE4 biology, highlighting how the structural characterization of isoforms informs drug design. We conduct a critical evaluation of preclinical and clinical data across various diseases, including inflammatory bowel diseases (IBDs), alcoholic liver disease, nonalcoholic fatty liver disease (NAFLD), liver fibrosis, and digestive tract tumors, with an emphasis on mechanisms extending beyond cAMP modulation, such as microbiota remodeling and immune reprogramming. Additionally, we address challenges in clinical translation, including biomarker discovery and the heterogeneity of trial outcomes, and propose a roadmap for future research directions. Full article

Phosphodiesterase 4 (PDE4) is a key regulator of cyclic adenosine monophosphate (cAMP) signalling in cardiomyocytes, controlling contractility, calcium handling, and hypertrophic responses. PDE4 provides spatial and temporal precision to cAMP signalling, particularly under β-adrenergic stimulation, through its compartmentalised activity in subcellular nanodomains, including the sarcoplasmic reticulum, plasma membrane and nuclear envelope. This review highlights the cardiac PDE4 isoforms PDE4A, PDE4B and PDE4D, focusing on their distinct localisation and contributions to cardiac physiology and pathophysiology, particularly in heart failure and arrhythmias. Although PDE4 plays a smaller role in overall cAMP hydrolysis in human hearts than in rodents, its compartmentalised function remains critical. Recent therapeutic advances have shifted from pan-PDE4 inhibitors to isoform-specific approaches to enhance efficacy while minimising systemic toxicity. We discuss the potential of selective PDE4 modulators, gene therapies and combination strategies in restoring cAMP compartmentation and preventing maladaptive cardiac remodelling. By integrating rodent and human studies, this review underscores the translational challenges and therapeutic opportunities surrounding PDE4, positioning it as both a key regulator of cardiac signalling and a promising target for heart failure therapies. Full article

Silicosis is an interstitial lung disease (ILD) caused by prolonged inhalation of silica particles. Acute lung injury (ALI) is a critical clinical syndrome involving bilateral lung infiltration and acute hypoxic respiratory failure. However, there is currently no effective treatment for these two diseases. Previous research has established that cyclic adenosine monophosphate (cAMP) is pivotal in the pathogenesis of silicosis and acute lung injury. Phosphodiesterase 4 (PDE4) is a hydrolase enzyme of cAMP, and BI 1015550, as an inhibitor of PDE4B, is expected to be a candidate drug for treating both. BI 1015550 has shown certain anti-inflammatory and anti-fibrotic properties in systemic sclerosis-associated interstitial lung disease (SSc-ILD) and idiopathic pulmonary fibrosis (IPF), but there is a lack of research on silicosis and acute lung injury. In this research, we successfully synthesized BI 1015550 autonomously and demonstrated that it could significantly improve lung fibrosis and inflammation in a silica-induced silicosis mouse model. Furthermore, we found that BI 1015550 could also alleviate lung inflammation in a Lipopolysaccharide (LPS)-induced acute lung injury mouse model. The mechanism of action may involve the regulation of cAMP-related signaling pathways. Full article

Phosphodiesterase 4 (PDE4) catalyzes cyclic adenosine monophosphate (cAMP) hydrolysis, playing a crucial role in the cAMP signaling pathway. cAMP is a secondary messenger involved in numerous physiological functions, such as inflammatory responses, immune responses, neural activity, learning, and memory. PDE4 inhibition is important for controlling anti-inflammatory and neuroprotective effects. In this review, we provide a comprehensive overview of the molecular functions and properties of human PDE4s. The study presents detailed sequence information for the PDE4 isoforms and the structural properties of the catalytic domain in members of the PDE4 family. We also review the inhibitory effects of the PDE4 inhibitors roflumilast and cilomilast related to respiratory diseases in PDE4. The crystal structures of PDE4 in complex with roflumilast and cilomilast are also analyzed. This review provides useful information for the future design of novel PDE4 inhibitors. Full article

Background/Objectives: Complex regional pain syndrome (CRPS) is characterized by severe pain and reduced functionality, which can significantly affect an individual’s quality of life. The current treatment of CRPS is challenging. However, recent advances in diagnostic and treatment methods show promise for improving patient outcomes. This review aims to place the question of CRPS in a broader context and highlight the objectives of the research for future directions in the management of CRPS. Methods: This study involved a comprehensive literature review. Results: Research has identified three primary pathophysiological pathways that may explain the clinical variability observed in CRPS: inflammatory mechanisms, vasomotor dysfunction, and maladaptive neuroplasticity. Investigations into these pathways have spurred the development of novel diagnostic and treatment strategies focused on N-Methyl-D-aspartate Receptor Antagonists (NMDA), Toll-like receptor 4 (TLR-4), α1 and α2 adrenoreceptors, as well as the identification of microRNA (miRNA) biomarkers. Treatment methods being explored include immune and glial-modulating agents, intravenous immunoglobulin (IVIG) therapy, plasma exchange therapy, and neuromodulation techniques. Additionally, there is ongoing debate regarding the efficacy of other treatments, such as free radical scavengers, alpha-lipoic acid (ALA), dimethyl fumarate (DMF), adenosine monophosphate-activated protein kinase (AMPK) activators such as metformin, and phosphodiesterase-5 inhibitors such as tadalafil. Conclusions: The controversies surrounding the mechanisms, diagnosis, and treatment of CRPS have prompted researchers to investigate new approaches aimed at enhancing understanding and management of the condition, with the goal of alleviating symptoms and reducing associated disabilities. Full article

Background/Objectives Studies in rodents indicate that disruptions in both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) signaling pathways are involved in the development of hyperactive behavior. We examined whether vinpocetine, a phosphodiesterase type 1 inhibitor that enhances brain cAMP and cGMP levels, could mitigate locomotor hyperactivity in mice exposed to lead during early development. Methods Swiss mice were exposed to 90 ppm of lead in their drinking water throughout gestation and the first ten postnatal days. At postnatal day 10 (PN10), blood lead levels (BLLs) were about 30 µg/dL. At PN30, animals either received vinpocetine (20 mg/kg, i.p.) or a vehicle 4 h before the evaluation of locomotor activity in the open field. Results Lead-exposed males did not display differences in locomotor activity compared to controls, while lead-exposed females showed a significant increase in locomotion. Vinpocetine treatment significantly reversed the lead-induced hyperactivity in females. Conclusions These findings suggest that the cAMP and cGMP signaling pathways play a role in the hyperactivity induced by lead exposure. Full article

Cognitive disorders and psychiatric pathologies, particularly Alzheimer’s disease (AD) and Major depressive disorder (MDD), represent a considerable health burden, impacting millions of people in the United States and worldwide. Notably, comorbidities of MDD and anxiety are prevalent in the early stages of mild cognitive impairment (MCI), which is the preceding phase of Alzheimer’s disease and related dementia (ADRD). The symptoms of MDD and anxiety affect up to 80% of individuals in the advanced stages of the neurodegenerative conditions. Despite overlapping clinical manifestations, the pathogenesis of AD/ADRD and MDD remains inadequately elucidated. Until now, dozens of drugs for treating AD/ADRD have failed in clinical trials because they have not proven beneficial in reversing or preventing the progression of these neuropsychiatric indications. This underscores the need to identify new drug targets that could reverse neuropsychiatric symptoms and delay the progress of AD/ADRD. In this context, phosphodiesterase 4 (PDE4) arises as a primary enzyme in the modulation of cognition and mood disorders, particularly through its enzymatic action on cyclic adenosine monophosphate (cAMP) and its downstream anti-inflammatory pathways. Despite the considerable cognitive and antidepressant potential of PDE4 inhibitors, their translation into clinical practice is hampered by profound side effects. Recent studies have focused on the effects of PDE4 and its subtype-selective isoform inhibitors, aiming to delineate their precise mechanistic contributions to neuropsychiatric symptoms with greater specificity. This review aims to analyze the current advances regarding PDE4 inhibition—specifically the selective targeting of its isoforms and elucidate the therapeutic implications of enhanced cAMP signaling and the consequent anti-inflammatory responses in ameliorating the symptomatology associated with AD and ADRD. Full article

Tyrosyl-DNA phosphodiesterases 1 and 2 (TDP1 and TDP2) are important DNA repair enzymes that remove various adducts from the 3′- and 5′-ends of DNA, respectively. The suppression of the activity of these enzymes is considered as a promising adjuvant therapy for oncological diseases in combination with topoisomerase inhibitors. The simultaneous inhibition of TDP1 and TDP2 may result in greater antitumor effects, as these enzymes can mimic each other’s functions. We have previously shown that usnic acid-based sulfides can act as dual inhibitors, with TDP1 activity in the low micromolar range and their TDP2 at 1 mM. The oxidation of their sulfide moieties to sulfoxides led to an order of magnitude decrease in their cytotoxicity potential, while their TDP1 and TDP2 activity was preserved. In this work, we synthesized new series of usnic acid-based sulfides and their oxidized analogues, i.e., sulfoxides and sulfones, to systematically study these irregularities. The new compounds inhibit TDP1 with IC₅₀ values (the concentration of inhibitor required to reduce enzyme activity by half) in the 0.33–25 μM range. Most sulfides and some sulfoxides and sulfones inhibit TDP2 with an IC₅₀ = 138−421 μM. In addition, the most active compounds synergized (×4) with topotecan on the HeLa cell line as well as causing dose-dependent DNA damage, as confirmed by Comet assay. Sulfides with the 6-methylbenzoimidazol-2-yl substituent (8f, IC₅₀ = 0.33/138 μM, TDP1/2) and sulfones containing a pyridine-2-yl fragment (12k, IC₅₀ = 2/228 μM, TDP1/2) are the most potent derivatives and, therefore, are promising for further development. Full article

Pharmacological treatment of diabetes mellitus-induced erectile dysfunction (DMED) has become increasingly challenging due to the limited efficacy of phosphodiesterase type 5 inhibitors (PDE5i). As the global prevalence of DM continues, there is a critical need for novel therapeutic strategies to address DMED. In our previous studies, we found that Glutathione peroxidase 4 (GPX4), a ferroptosis inhibitor, can ameliorate DMED in diabetic rats. However, the specific role of GPX4 in corpus cavernosum smooth muscle cells (CCSMCs) and its regulatory mechanisms remain unclear. In this study, we established primary cultures of CCSMCs and systematically analyzed the role of GPX4 under high-glucose conditions. To further elucidate the upstream regulatory pathways of GPX4, we employed immunoprecipitation coupled with mass spectrometry (IP-MS) to identify potential interacting proteins. Additionally, co-immunoprecipitation (Co-IP) and cycloheximide (CHX) chase assays were conducted to explore the regulatory dynamics and post-translational stability of GPX4. Under high-glucose conditions, the expression of GPX4 in CCSMCs is significantly downregulated, leading to an increase in intracellular oxidative stress and heightened levels of ferroptosis, accompanied by dysfunction in smooth muscle cell relaxation. Furthermore, the CHX chase assay revealed that high glucose accelerates GPX4 protein degradation via the ubiquitin–proteasome pathway. Subsequent IP-MS identified NEDD4, an E3 ubiquitin ligase, as a potential interacting partner of GPX4. Further validation demonstrated that NEDD4 modulates the ubiquitination process of GPX4, thereby influencing its stability and expression. In conclusion, we identified NEDD4 as a key regulator of GPX4 stability through ubiquitin-mediated proteasomal degradation. These findings suggest potential therapeutic strategies targeting the NEDD4-GPX4 axis to alleviate DMED pathology. Full article

Background: Diffuse large B-cell lymphoma (DLBCL) is a common and often fatal malignancy. The standard-of-care immunochemotherapy, R-CHOP, cures only about 60% of DLBCL patients. Improving this cure rate will likely require the effective translation of basic biology knowledge into clinical activities. We previously identified the cyclic-AMP/phosphodiesterase 4 (PDE4) axis as an important modulator of lymphomagenic processes. We also showed that the FDA-approved PDE4 inhibitor roflumilast can suppress B-cell receptor (BCR) signals, phosphoinositide 3-kinase (PI3K) activity and angiogenesis. These data suggested that combining roflumilast with R-CHOP may be beneficial in DLBCL. Methods: We conducted a single-center, single-arm, open-label, phase 1 study of roflumilast in combination with the standard of care, R-CHOP (Ro+R-CHOP), in pathologically proven, treatment-naïve, high-risk DLBCL patients. Results: Ro+R-CHOP was safe, and at a median follow-up time of 44 months, 70% of patients were alive and disease free (median OS not reached, PFS 44% (95% CI, 21–92). In this pilot series, we found that the addition of roflumilast suppressed PI3K activity in peripheral blood mononuclear cells, and VEGF-A secretion in the urine. We also encountered preliminary evidence to suggest that the Ro+R-CHOP combination may be particularly beneficial to patients diagnosed with high-risk genetic subtypes of DLBCL, namely MCD and A53. Conclusions: These initial findings suggest that roflumilast may be an alternative agent able to inhibit BCR/PI3K activity and angiogenesis in DLBCL, and that the testing of Ro+R-CHOP in a larger series of genetically characterized tumors is warranted. This study was registered at ClinicalTrials.gov, number NCT03458546. Full article