Activity of apremilast in a patient with severe pemphigus vulgaris: case report.

Introduction: Although the treatment for pemphigus vulgaris (PV) has been revolutionized by the use of rituximab combined with corticosteroids, new effective therapies with a better safety profile are needed. Observation: A 67-year-old woman was diagnosed with severe mucosal PV, which was initially misdiagnosed as atypical Behçet's disease. Following an unsuccessful colchicine treatment, significant improvement was observed upon the introduction of apremilast: reduced pain, fewer lesions, and a stabilized weight. The discontinuation of apremilast led to a rapid relapse. Retrospective analysis through anti-Dsg3 ELISA indicated a gradual decrease in antibody levels during the apremilast treatment. Discussion: Apremilast, a phosphodiesterase 4 inhibitor approved for psoriasis and Behçet's disease's related oral ulcers treatment, demonstrated its efficacy in this PV case. This is the second case report highlighting the effectiveness of apremilast for PV treatment. Apremilast's ability to upregulate cyclic adenosine monophosphate (cAMP) levels appears to contribute to the stabilization of keratinocyte adhesion. Conclusion: Apremilast may be a promising therapeutic option for the treatment of pemphigus, with an innovative mechanism of action, no induced immunosuppression, and good tolerance. It could be a good alternative to steroids, in the treatment regimen of steroids combined with rituximab.

Management of Keloid-Associated Pruritus With Topical Crisaborole 2% Ointment: A Case Report.

Introduction: The pathophysiology of keloid formation is poorly understood, and current treatments, including intralesional corticosteroids, cryotherapy, and surgery, are often associated with high resistance to treatment and recurrence. The multifactorial pathogenesis of keloid formation suggests that aberrant inflammatory cytokine signaling associated with keratinocyte dysregulation may contribute to keloid-associated pruritus. Case Presentation: In this paper, we report 2 cases of keloid-associated pruritus that were successfully treated with topical crisaborole 2% ointment, a phosphodiesterase 4 (PDE4) inhibitor. Both patients had previously undergone multiple unsuccessful treatments before being treated with crisaborole 2% ointment. In both cases, the patients experienced complete relief of pruritus with no significant change in keloid size, thickness, or appearance. Conclusion: We propose that PDE4 inhibitors, such as crisaborole, may be an effective therapy for keloid- associated pruritus.

PDE4 inhibitors: potential protective effects in inflammation and vascular diseases.

Phosphodiesterase 4 (PDE4) inhibitors are effective therapeutic agents for various inflammatory diseases. Roflumilast, apremilast, and crisaborole have been developed and approved for the treatment of chronic obstructive pulmonary disease psoriatic arthritis, and atopic dermatitis. Inflammation underlies many vascular diseases, yet the role of PDE4 inhibitors in these diseases remains inadequately explored. This review elucidates the clinical applications and anti-inflammatory mechanisms of PDE4 inhibitors, as well as their potential protective effects on vascular diseases. Additionally, strategies to mitigate the adverse reactions of PDE4 inhibitors are discussed. This article emphasizes the need for further exploration of the therapeutic potential and clinical applications of PDE4 inhibitors in vascular diseases.

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Phosphodiesterase (PDE) hydrolyze cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), and involve in the regulation of cellular physiological processes and neurological functions, including neuronal plasticity, synaptogenesis, synaptic transmission, memory formation and cognitive function by catalyzing the hydrolysis of intracellular cAMP and cGMP. A large number of basic and clinical studies have shown that PDE4 inhibitors block or ameliorate the occurrence and development of central nervous system (CNS) diseases by inhibiting cAMP hydrolysis, increasing cAMP content and enhancing its downstream effects. PDE4 inhibitors have long-term potentiation effect, which can enhance phosphorylation of cAMP response element binding protein (CREB) and upregulate expression of memory related Arc genes in hippocampal neurons, thereby improving cognitive impairment and Alzheimer's disease-like symptoms; and also resist the occurrence and development of Parkinson's disease by reducing the cytotoxicity induced by α-syn and increasing the effect of miR-124-3p on cell activity. Alteration of PDE4 activity is the molecular basis of psychosis and cognitive disorders, therefore it is considered as one of the therapeutic targets for schizophrenia. PDE4 inhibitors play a role in depression; Autism spectrum and Huntington's disease by inhibiting the advanced glycation end product receptor (RAGE), TLR4 and NLRP3 pathways in the hippocampus, reducing the activation of microglia and the production of interleukin-1ß, down-regulating HMGB1/RAGE signaling pathway and inhibiting inflammatory factors and Increase the nociception threshold. PDE4 inhibitors might be used in treatment of fragile X syndrome by regulating the level of cAMP and affecting the expression of fragile X mental retardation protein (FMRP). PDE4 inhibitors can also promote the differentiation of oligodendrocyte progenitor cells and enhance myelination, which has potential in the treatment of multiple sclerosis. PDE4 also related to Bipolar disorder which may be one of the therapeutic targets. At present, several PDE4 inhibitors are on clinical trials for treatment of CNS diseases. This article reviews and discusses the progress on basic researches and clinical trials of PDE4 inhibitors in CNS diseases, providing reference for the prevention and treatment of CNS diseases and the development of new drugs.

2% Crisaborole Ointment for the Treatment of Chronic Cheilitis Caused by Lip Tattoos.

The increasing popularity of tattoo art, including facial cosmetic tattoos, has led to a growing societal acceptance of tattoos. However, complications such as lip inflammation following cosmetic lip tattoos remain a concern. This article presents the case of a 47-year-old Asian woman who experienced recurrent lip swelling, purulent discharge, and scarring after receiving lip tattoos. Despite previous treatment with corticosteroid injections yielding unsatisfactory results, the patient showed significant improvement with topical application of 2% Crisaborole, a phosphodiesterase-4 inhibitor. Crisaborole modulates intracellular cyclic adenosine monophosphate levels, thereby reducing tissue inflammation and swelling associated with chronic cheilitis. Additionally, pulse laser therapy was effective in addressing residual tattoo pigment and scar tissue. This case highlights the therapeutic challenges of managing chronic inflammatory diseases of the lips secondary to cosmetic tattoos and introduces Crisaborole as a promising treatment option, offering insights for managing similar conditions in the future.

Amelioration of functional and histopathological consequences after spinal cord injury through phosphodiesterase 4D (PDE4D) inhibition.

Spinal cord injury (SCI) is a life-changing event that severely impacts the patient's quality of life. Modulating neuroinflammation, which exacerbates the primary injury, and stimulating neuro-regenerative repair mechanisms are key strategies to improve functional recovery. Cyclic adenosine monophosphate (cAMP) is a second messenger crucially involved in both processes. Following SCI, intracellular levels of cAMP are known to decrease over time. Therefore, preventing cAMP degradation represents a promising strategy to suppress inflammation while stimulating regeneration. Intracellular cAMP levels are controlled by its hydrolyzing enzymes phosphodiesterases (PDEs). The PDE4 family is most abundantly expressed in the central nervous system (CNS) and its inhibition has been shown to be therapeutically relevant for managing SCI pathology. Unfortunately, the use of full PDE4 inhibitors at therapeutic doses is associated with severe emetic side effects, hampering their translation toward clinical applications. Therefore, in this study, we evaluated the effect of inhibiting specific PDE4 subtypes (PDE4B and PDE4D) on inflammatory and regenerative processes following SCI, as inhibitors selective for these subtypes have been demonstrated to be well-tolerated. We reveal that administration of the PDE4D inhibitor Gebr32a, even when starting 2 dpi, but not the PDE4B inhibitor A33, improved functional as well as histopathological outcomes after SCI, comparable to results obtained with the full PDE4 inhibitor roflumilast. Furthermore, using a luminescent human iPSC-derived neurospheroid model, we show that PDE4D inhibition stabilizes neural viability by preventing apoptosis and stimulating neuronal differentiation. These findings strongly suggest that specific PDE4D inhibition offers a novel therapeutic approach for SCI.

Inhibition of phosphodiesterase 4 attenuates aquaporin 4 expression and astrocyte swelling following cerebral ischemia/reperfusion injury.

We have previously shown that phosphodiesterase 4 (PDE4) inhibition protects against neuronal injury in rats following middle cerebral artery occlusion/reperfusion (MCAO/R). However, the effects of PDE4 on brain edema and astrocyte swelling are unknown. In this study, we showed that inhibition of PDE4 by Roflumilast (Roflu) reduced brain edema and brain water content in rats subjected to MCAO/R. Roflu decreased the expression of aquaporin 4 (AQP4), while the levels of phosphorylated protein kinase B (Akt) and forkhead box O3a (FoxO3a) were increased. In addition, Roflu reduced cell volume and the expression of AQP4 in primary astrocytes undergoing oxygen and glucose deprivation/reoxygenation (OGD/R). Consistently, PDE4B knockdown showed similar effects as PDE4 inhibition; and PDE4B overexpression rescued the inhibitory role of PDE4B knockdown on AQP4 expression. We then found that the effects of Roflu on the expression of AQP4 and cell volume were blocked by the Akt inhibitor MK2206. Since neuroinflammation and astrocyte activation are the common events that are observed in stroke, we treated primary astrocytes with interleukin-1ß (IL-1ß). Astrocytes treated with IL-1ß showed decreased AQP4 and phosphorylated Akt and FoxO3a. Roflu significantly reduced AQP4 expression, which was accompanied by increased phosphorylation of Akt and FoxO3a. Furthermore, overexpression of FoxO3a partly reversed the effect of Roflu on AQP4 expression. Our findings suggest that PDE4 inhibition limits ischemia-induced brain edema and astrocyte swelling via the Akt/FoxO3a/AQP4 pathway. PDE4 is a promising target for the intervention of brain edema after cerebral ischemia.

Low PDE4A expression promoted the progression of ovarian cancer by inducing Snail nuclear translocation.

Widespread metastasis is the primary reason for the high mortality associated with ovarian cancer (OC), and effective targeted therapy for tumor aggressiveness is still insufficient in clinical practice. Therefore, it is urgent to find new targets to improve prognosis of patients. PDE4A is a cyclic nucleotide phosphodiesterase that plays a crucial role in the occurrence and development in various malignancies. Our study firstly reported the function of PDE4A in OC. Expression of PDE4A was validated through bioinformatics analysis, RT-qPCR, Western blot, and immunohistochemistry. Additionally, its impact on cell growth and motility was assessed via in vitro and in vivo experiments. PDE4A was downregulated in OC tissues compared with normal tissues and low PDE4A expression was correlated with poor clinical outcomes in OC patients. The knockdown of PDE4A significantly promoted the proliferation, migration and invasion of OC cells while overexpression of PDE4A resulted in the opposite effect. Furthermore, smaller and fewer tumor metastatic foci were observed in mice bearing PDE4A-overexpressing OVCAR3 cells. Mechanistically, downregulation of PDE4A expression can induce epithelial-mesenchymal transition (EMT) and nuclear translocation of Snail, which suggests that PDE4A plays a pivotal role in suppressing OC progression. Notably, Rolipram, the PDE4 inhibitor, mirrored the effects observed with PDE4A deletion. In summary, the downregulation of PDE4A appears to facilitate OC progression by modulating the Snail/EMT pathway, underscoring the potential of PDE4A as a therapeutic target against ovarian cancer metastasis.

Structural optimization of Moracin M as novel selective phosphodiesterase 4 inhibitors for the treatment of idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and high mortality lung disease. Although the antifibrotic drugs pirfenidone and nintedanib could slow the rate of lung function decline, the usual course of the condition is inexorably to respiratory failure and death. Therefore, new approaches and novel therapeutic drugs for the treatment of IPF are urgently needed. And the selective PDE4 inhibitor has in vivo and in vitro anti-fibrotic effects in IPF models. But the clinical application of most PDE4 inhibitors are limited by their unexpected and severe side effects such as nausea, vomiting, and diarrhea. Herein, structure-based optimizations of the natural product Moracin M resulted in a novel a novel series of 2-arylbenzofurans as potent PDE4 inhibitors. The most potent inhibitor L13 has an IC50 of 36 ± 7 nM with remarkable selectivity across the PDE families and administration of L13·citrate (10.0 mg/kg) exhibited comparable anti-pulmonary fibrosis effects to pirfenidone (300 mg/kg) in a bleomycin-induced IPF mice model, indicate that L13 is a potential lead for the treatment of IPF.

Topical Prescription Management.

With recent advances in topical therapies for atopic dermatitis (AD), steroid-sparing options like calcineurin inhibitors, Janus kinase (JAK) inhibitors, and phosphodiesterase-4 (PDE-4) inhibitors are becoming mainstays in therapy, underscoring the importance of careful selection and usage of topical corticosteroids (TCSs) to minimize side effects. Alongside the necessity of emollient use, these steroid-sparing alternatives offer rapid itch relief and efficacy in improving disease severity. While TCSs still hold a prominent role in AD management, promising novel topical treatments like tapinarof and live biotherapeutics to modulate the skin microbiome are also discussed. Overall, the recent addition of novel topical therapies offers diverse options for AD management and underscores the importance of topical treatments in the management of AD.

Efficacy and Safety of Crisaborole Ointment 2% in Chinese Patients Aged ≥ 2 Years with Mild to Moderate Atopic Dermatitis.

INTRODUCTION: Atopic dermatitis (AD) is a chronic immuno-inflammatory skin disease. Crisaborole ointment, 2%, is a nonsteroidal phosphodiesterase 4 inhibitor approved for the treatment of mild to moderate AD. This post hoc analysis assesses the efficacy and safety of crisaborole in Chinese patients aged ≥ 2 years with mild to moderate AD. METHODS: We evaluated the efficacy and safety of crisaborole in Chinese patients from the vehicle-controlled, phase 3 CrisADe CLEAR study. Patients were randomly assigned 2:1 to receive crisaborole or vehicle twice daily, respectively, for 28 days. The primary endpoint was percent change from baseline in Eczema Area and Severity Index (EASI) total score at day 29. Key secondary endpoints were improvement in Investigator's Static Global Assessment (ISGA), ISGA success, and change from baseline in weekly average Peak Pruritus Numerical Rating Scale (PP-NRS) score. Adverse events were documented. RESULTS: Of 391 patients in the overall study, 237 were from China, 157 assigned to crisaborole and 80 assigned to vehicle. A greater reduction in percent change from baseline in EASI total score at day 29 was shown in the crisaborole vs. vehicle group (least squares mean [LSM]: -66.34 [95% (confidence interval) CI -71.55 to -61.12] vs. -50.18 [95% CI -58.02 to -42.34]). Response rates for achievement of ISGA improvement (43.2% [95% CI 35.4-51.1] vs. 33.4% [95% CI 22.5-44.2]) and ISGA success (31.7% [95% CI 24.3-39.0] vs. 21.5% [95% CI 12.1-30.9]) at day 29 were higher in the crisaborole vs. vehicle group. A greater reduction in change from baseline in weekly average PP-NRS score at week 4 was observed in the crisaborole vs. vehicle group (LSM: -1.98 [95% CI -2.34 to -1.62] vs. -1.08 [95% CI -1.63 to -0.53]). No new safety signals were observed. CONCLUSION: Crisaborole was effective and well tolerated in Chinese patients aged ≥ 2 years with mild to moderate AD. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04360187.

Advancing Treatment in Atopic Dermatitis: A Comprehensive Review of Clinical Efficacy, Safety, and Comparative Insights Into Corticosteroids, Calcineurin Inhibitors, and Phosphodiesterase-4 Inhibitors as Topical Therapies.

Atopic dermatitis (AD) is a pervasive and multifaceted dermatological disorder causing daily distress to afflicted individuals worldwide. This comprehensive review synthesizes the historical and contemporary advancements in therapeutic strategies, offering a critical analysis of their efficacy, safety profiles, and adaptability. The enduring role of topical corticosteroids in managing AD is examined, acknowledging their potent anti-inflammatory properties alongside their potential adverse side effects, particularly in extended usage. The article explores the utilization of topical calcineurin inhibitors like tacrolimus and pimecrolimus, highlighting their novel anti-inflammatory pathways while also scrutinizing concerns over potential malignancies that relegate them to second-line therapy. The present investigation features the emergence of crisaborole, a phosphodiesterase four inhibitor. Its innovative mode of action, benign safety profile, and applicability to mild and moderate AD are thoroughly evaluated. The review also includes challenges, particularly cost considerations, which constrain accessibility and necessitate nuanced implementation in therapeutic regimens. This study underscores the need for persistent investigation, teamwork, and innovations in managing AD. In this regard, AD requires a united approach between clinicians, researchers, affected individuals, and policymakers to refine patient-focused treatment and develop precise, economical strategies to address this chronic and frequently life-altering health condition.

Endothelial phosphodiesterase 4B inactivation ameliorates endothelial-to-mesenchymal transition and pulmonary hypertension.

Pulmonary hypertension (PH) is a fatal disorder characterized by pulmonary vascular remodeling and obstruction. The phosphodiesterase 4 (PDE4) family hydrolyzes cyclic AMP (cAMP) and is comprised of four subtypes (PDE4A-D). Previous studies have shown the beneficial effects of pan-PDE4 inhibitors in rodent PH; however, this class of drugs is associated with side effects owing to the broad inhibition of all four PDE4 isozymes. Here, we demonstrate that PDE4B is the predominant PDE isozyme in lungs and that it was upregulated in rodent and human PH lung tissues. We also confirmed that PDE4B is mainly expressed in the lung endothelial cells (ECs). Evaluation of PH in Pde4b wild type and knockout mice confirmed that Pde4b is important for the vascular remodeling associated with PH. In vivo EC lineage tracing demonstrated that Pde4b induces PH development by driving endothelial-to-mesenchymal transition (EndMT), and mechanistic studies showed that Pde4b regulates EndMT by antagonizing the cAMP-dependent PKA-CREB-BMPRII axis. Finally, treating PH rats with a PDE4B-specific inhibitor validated that PDE4B inhibition has a significant pharmacological effect in the alleviation of PH. Collectively, our findings indicate a critical role for PDE4B in EndMT and PH, prompting further studies of PDE4B-specific inhibitors as a therapeutic strategy for PH.

Targeting phosphodiesterase 4 as a potential therapy for Parkinson's disease: a review.

Phosphodiesterases (PDEs) have become a promising therapeutic target for various disorders. PDEs are a vast and diversified family of enzymes that degrade cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which have several biochemical and physiological functions. Phosphodiesterase 4 (PDE4) is the most abundant PDE in the central nervous system (CNS) and is extensively expressed in the mammalian brain, where it catalyzes the hydrolysis of intracellular cAMP. An alteration in the balance of PDE4 and cAMP results in the dysregulation of different biological mechanisms involved in neurodegenerative diseases. By inhibiting PDE4 with drugs, the levels of cAMP inside the cells could be stabilized, which may improve the symptoms of mental and neurological disorders such as memory loss, depression, and Parkinson's disease (PD). Though numerous studies have shown that phosphodiesterase 4 inhibitors (PDE4Is) are beneficial in PD, there are presently no approved PDE4I drugs for PD. This review presents an overview of PDE4Is and their effects on PD, their possible underlying mechanism in the restoration/protection of dopaminergic cell death, which holds promise for developing PDE4Is as a treatment strategy for PD. Methods on how these drugs could be effectively delivered to develop as a promising treatment for PD have been suggested.

A phosphodiesterase 4 (PDE4) inhibitor, amlexanox, reduces neuroinflammation and neuronal death after pilocarpine-induced seizure.

Epilepsy, a complex neurological disorder, is characterized by recurrent seizures caused by aberrant electrical activity in the brain. Central to this study is the role of lysosomal dysfunction in epilepsy, which can lead to the accumulation of toxic substrates and impaired autophagy in neurons. Our focus is on phosphodiesterase-4 (PDE4), an enzyme that plays a crucial role in regulating intracellular cyclic adenosine monophosphate (cAMP) levels by converting it into adenosine monophosphate (AMP). In pathological states, including epilepsy, increased PDE4 activity contributes to a decrease in cAMP levels, which may exacerbate neuroinflammatory responses. We hypothesized that amlexanox, an anti-inflammatory drug and non-selective PDE4 inhibitor, could offer neuroprotection by addressing lysosomal dysfunction and mitigating neuroinflammation, ultimately preventing neuronal death in epileptic conditions. Our research utilized a pilocarpine-induced epilepsy animal model to investigate amlexanox's potential benefits. Administered intraperitoneally at a dose of 100 â€‹mg/kg daily following the onset of a seizure, we monitored its effects on lysosomal function, inflammation, neuronal death, and cognitive performance in the brain. Tissue samples from various brain regions were collected at predetermined intervals for a comprehensive analysis. The study's results were significant. Amlexanox effectively improved lysosomal function, which we attribute to the modulation of zinc's influx into the lysosomes, subsequently enhancing autophagic processes and decreasing the release of inflammatory factors. Notably, this led to the attenuation of neuronal death in the hippocampal region. Additionally, cognitive function, assessed through the modified neurological severity score (mNSS) and the Barnes maze test, showed substantial improvements after treatment with amlexanox. These promising outcomes indicate that amlexanox has potential as a therapeutic agent in the treatment of epilepsy and related brain disorders. Its ability to combat lysosomal dysfunction and neuroinflammation positions it as a potential neuroprotective intervention. While these findings are encouraging, further research and clinical trials are essential to fully explore and validate the therapeutic efficacy of amlexanox in epilepsy management.

A proof of concept phase II study with the PDE-4 inhibitor roflumilast in patients with mild cognitive impairment or mild Alzheimer's disease dementia (ROMEMA): study protocol of a double-blind, randomized, placebo-controlled, between-subjects trial.

BACKGROUND: Research into the neurobiological underpinnings of learning and memory has demonstrated the cognitive-enhancing effects associated with diverse classes of phosphodiesterase (PDE) inhibitors. Specific PDE inhibitors have been identified to improve neuronal communication through selective inhibition of PDE activity. Roflumilast, a PDE4 inhibitor, has demonstrated efficacy in enhancing episodic memory in healthy adults and elderly participants with pronounced memory impairment, indicative of amnestic mild cognitive impairment (aMCI). In alignment with these findings, the present protocol aims to provide a proof of concept phase II of the potential of roflumilast to aid patients diagnosed with (a)MCI or mild Alzheimer's disease (AD) dementia. METHODS: The study will be conducted according to a double-blind, randomized placebo-controlled, between-subjects design. Participants with (a)MCI and mild AD dementia will be recruited through the Memory Clinic at the Maastricht University Medical Centre + (MUMC +) in Maastricht, the Netherlands, alongside outreach through regional hospitals, and social media. The study will have three arms: placebo, 50 µg roflumilast, and 100 µg roflumilast, with a treatment duration of 24 weeks. The primary outcome measure will focus on the assessment of episodic memory, as evaluated through participants' performance on the 15-word Verbal Learning Task (VLT). Our secondary objectives are multifaceted, including an exploration of various cognitive domains. In addition, insights into the well-being and daily functioning of participants will be investigated through interviews with both the participants and their (informal) caregivers, we are interested in the well-being and daily functioning of the participants. DISCUSSION: The outcomes of the present study aim to elucidate the significance of the PDE4 inhibition mechanism as a prospective therapeutic target for enhancing cognitive function in individuals with (a)MCI and mild AD dementia. Identifying positive effects within these patient cohorts could extend the relevance of this treatment to encompass a broader spectrum of neurological disorders. TRIAL REGISTRATION: The Medical Ethics Committee of MUMC + granted ethics approval for the 4th version of the protocol on September 10th, 2020. The trial was registered at the European Drug Regulatory Affairs Clinical Trials (EudraCT) registered on the 19th of December 2019 ( https://www.clinicaltrialsregister.eu/ctr-search/trial/2019-004959-36/NL ) and ClinicalTrial.gov (NCT04658654, https://clinicaltrials.gov/study/NCT04658654?intr=roflumilast&cond=mci&rank=1 ) on the 8th of December 2020. The Central Committee on Research Involving Human Subjects (CCMO) granted approval on the 30th of September 2020.

Ribociclib leverages phosphodiesterase 4 inhibition in the treatment of neutrophilic inflammation and acute respiratory distress syndrome.

INTRODUCTION: Overwhelming neutrophil activation and oxidative stress significantly contribute to acute respiratory distress syndrome (ARDS) pathogenesis. However, the potential of repurposing ribociclib, a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor used clinically in cancer treatment, for treating neutrophilic ARDS remains uncertain. This study illustrated the ability and underlying mechanism of ribociclib for treating ARDS and neutrophilic inflammation. METHODS: Primary human neutrophils were used to determine the therapeutic effects of ribociclib on respiratory bursts, chemotactic responses, and inflammatory signaling. In vitro and silico analyses were performed to determine the underlying molecular mechanisms. The potential of ribociclib repurposing was evaluated using an in vivo ARDS model in lipopolysaccharide (LPS)-primed mice. RESULTS: We found that treatment using ribociclib markedly limited overabundant oxidative stress (reactive oxygen species [ROS]) production and chemotactic responses (integrin levels and adhesion) in activated human neutrophils. Ribociclib was also shown to act as a selective inhibitor of phosphodiesterase 4 (PDE4), thereby promoting the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway, leading to the inhibition of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) phosphorylation, and calcium influx. Notably, prophylactic administration and post-treatment with ribociclib ameliorated neutrophil infiltration, lung inflammation, accumulation of oxidative stress, pulmonary destruction, and mortality in mice with LPS-induced ARDS. CONCLUSION: We demonstrated for the first time that ribociclib serves as a novel PDE4 inhibitor for treating neutrophilic inflammation and ARDS. The repurposing ribociclib and targeting neutrophilic PDE4 offer a potential off-label alternative for treating lung lesions and other inflammatory conditions.

Elevated PDE4C level serves as a candidate diagnostic biomarker and correlates with poor survival in thyroid carcinoma.

Thyroid carcinoma (THCA) is the most common endocrine cancer. Phosphodiesterase (PDE) 4 enzyme family, as specific regulator of cyclic adenosine monophosphate, may play a important role in THCA. However, few studies on PDE4 enzyme family in THCA have been reported yet. Therefore, this study aimed to systematically analyze the changes of PDE4 enzyme family in THCA, and look for potential target for THCA therapy. We systematically analyzed the expression differences, prognostic value, genetic alteration, methylation modification, and the correlation with tumor immune microenvironment of PDE4 family in THCA using several public databases, including TCGA, GEO, GSCA, TNMplot, cBioPortal, DiseaseMeth and TIMER. Besides, functional enrichment analysis and protein-protein interaction (PPI) network of PDE4 family was investigated using Metascape and STRING databases. The expression levels of PDE4A, PDE4B and PDE4D were down-regulated in THCA patients at different cancer stages, while the expression level of PDE4C was significantly up-regulated. Moreover, THCA patients with higher PDE4C expression had shorter progress free survival compared with those with lower PDE4C expression. The low genomic alteration frequencies and mildly increased methylation levels of PDE4 family were found in THCA patients. Except for PDE4A, the expression levels of PDE4B, PDE4C and PDE4D could affect many immune cells infiltration during THCA progression. Four PDE4 subtypes were all enriched in cAMP catabolic process. Nevertheless, PDE4C was not enriched in the cAMP binding signal pathway, and PDE4B was not enriched in the G alphas signaling events. Notably, PDE4C participated in cAMP metabolic process by regulating adenylate cyclases (ADCYs), which involved ADCY1, ADCY5, ADCY6, ADCY8 and ADCY9. The findings of this study provide a partial basis for the role of PDE4 family in the occurrence and development of THCA. In addition, this study also suggested that PDE4C might be a potential prognostic marker of THCA, which could serve as a reference for future basic and clinical research.

Effects of oral roflumilast therapy on body weight and cardiometabolic parameters in patients with psoriasis - results from a randomized controlled trial (PSORRO).

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.

The Dosing Strategy to Improve Adherence to Roflumilast in Treatment for Chronic Obstructive Lung Disease: A Systemic Review and Meta-Analysis.

Background: The clinical efficacy of roflumilast, an oral phosphodiesterase-4 inhibitor, has been demonstrated in patients with severe chronic obstructive pulmonary disease (COPD). However, roflumilast has shown frequent adverse drug reactions (ADRs). This study was performed to investigate the dosing strategy that will improve adherence to roflumilast in COPD. Methods: We conducted a systematic review and meta-analysis using PubMed, Embase, and Cochrane Central Register. The dosing strategy for roflumilast was classified into a dose-escalation group and a low-dose group. We investigated clinical outcomes according to dosing strategy. Results: Five clinical trials involving 2424 patients were included. Both the dose-escalation and the low-dose groups showed a decrease in discontinuation rate compared to the standard dosing group for roflumilast (risk ratio [RR], 0.81; 95% confidence interval [CI], 0.67-0.97; P = 0.02 and RR, 0.62; 95% CI, 0.48-0.80; P < 0.01, respectively). In the two strategies, the pooled proportions of discontinuation were 27.9% and 11.7%, respectively. Although the pooled proportion of any ADR was not statistically decreased in the two strategies, diarrhea was significantly reduced in the low-dose group compared to the standard group (RR, 0.58; 95% CI, 0.42-0.82; P < 0.01). The pooled incidence of acute exacerbations was similar between the low-dose and the standard groups (22.9% and 20.1%, respectively; P = 0.27). Conclusion: Our findings show that the two alternative dosing strategies might have the benefit of improving adherence to roflumilast in COPD. Further large-scale trials are required to support our findings.