Clinical Implication of Phosphodiesterase-4-Inhibition

Pharmacological potential of cyclic nucleotide signaling in immunity

Cyclic nucleotides are important signaling molecules that play many critical physiological roles including controlling cell fate and development, regulation of metabolic processes, and responding to changes in the environment. Cyclic nucleotides are also pivotal regulators in immune signaling, orchestrating intricate processes that maintain homeostasis and defend against pathogenic threats. This review provides a comprehensive examination of the pharmacological potential of cyclic nucleotide signaling pathways within the realm of immunity. Beginning with an overview of the fundamental roles of cAMP and cGMP as ubiquitous second messengers, this review delves into the complexities of their involvement in immune responses. Special attention is given to the challenges associated with modulating these signaling pathways for therapeutic purposes, emphasizing the necessity for achieving cell-type specificity to avert unintended consequences. A major focus of the review is on the recent paradigm-shifting discoveries regarding specialized cyclic nucleotide signals in the innate immune system, notably the cGAS-STING pathway. The significance of cyclic dinucleotides, exemplified by 2'3'-cGAMP, in controlling immune responses against pathogens and cancer, is explored. The evolutionarily conserved nature of cyclic dinucleotides as antiviral agents, spanning across diverse organisms, underscores their potential as targets for innovative immunotherapies. Findings from the last several years have revealed a striking diversity of novel bacterial cyclic nucleotide second messengers which are involved in antiviral responses. Knowledge of the existence and precise identity of these molecules coupled with accurate descriptions of their associated immune defense pathways will be essential to the future development of novel antibacterial therapeutic strategies. The insights presented herein may help researchers navigate the evolving landscape of immunopharmacology as it pertains to cyclic nucleotides and point toward new avenues or lines of thinking about development of therapeutics against the pathways they regulate.

PDE4D and miR-203 are promising biomarkers for canine atopic dermatitis

BACKGROUND

Canine atopic dermatitis (CAD) is a common genetically predisposed, inflammatory, and pruritic skin disorder that affects dogs globally. To date, there are no specific biomarkers available to diagnose CAD, and the current diagnosis is based on a combination of criteria including patient history, clinical signs, and exclusion of other relevant differential diagnoses.

METHODS AND RESULTS

We examined the gene expression of phosphodiesterase 4D (PDE4D) in peripheral blood mononuclear cells (PBMCs), as well as miR-203 and miR-483 in plasma, in three groups: healthy dogs, CAD dogs, and other inflammatory pruritic skin diseases (OIPSD) such as pemphigus foliaceus, scabies, cutaneous lymphoma, and dermatophytosis. Our results showed that PDE4D gene expression in the CAD group is statistically higher compared to those in the healthy and OIPSD groups, suggesting PDE4D may be a specific marker for CAD. Nevertheless, no correlation was found between PDE4D gene expression levels and the lesion severity gauged by CAD severity index-4 (CADESI-4). We also showed that miR-203 is a generic marker for clinical dermatitis and differentiates both CAD and OIPSD inflammatory conditions from healthy controls.

CONCLUSIONS

We show that PDE4D is a potential marker to differentiate CAD from non-atopic healthy and OIPSD while miR-203 may be a potential marker for general dermatologic inflammation. Future study of PDE4D and miR-203 on a larger scale is warranted.

Topical Application of a PDE4 Inhibitor Ameliorates Atopic Dermatitis through Inhibition of Basophil IL-4 Production

Phosphodiesterase 4 inhibitors have been approved for the treatment of atopic dermatitis. However, the cellular and molecular mechanisms underlying their therapeutic effect remain to be fully elucidated. In this study, we addressed this unsolved issue by analyzing the action of difamilast, a novel phosphodiesterase 4 inhibitor, on an oxazolone-induced skin allergic inflammation commonly used as a mouse model of atopic dermatitis. Topical application of difamilast ameliorated skin inflammation in association with reduced IL-4 expression even when the treatment commenced 4 days after the initiation of oxazolone challenge, showing its therapeutic effect on atopic dermatitis. IL-4-deficient mice displayed milder skin inflammation than did wild-type mice, and the difamilast treatment had little or no further therapeutic effect. This was also the case in mice depleted of basophils, predominant producers of IL-4 in the skin lesion, suggesting that difamilast may act on basophils. Notably, basophils accumulating in the skin lesion showed highly upregulated expression of Pde4b encoding the B subtype of the phosphodiesterase 4 family. Difamilast suppressed IL-4 production from basophils activated in vitro, at least in part, through inhibition of ERK phosphorylation. Taken together, difamilast appeared to ameliorate atopic dermatitis inflammation through the suppression of basophil IL-4 production in the skin lesion.

Combined PDE4+MEK inhibition shows antiproliferative effects in NRASQ61 mutated melanoma preclinical models

Upregulation of phosphodiesterase type 4 (PDE4) has been associated with worse prognosis in several cancers. In melanomas harboring NRAS mutations, PDE4 upregulation has been shown to trigger a switch in signaling from BRAF to RAF1 which leads to mitogen-activated protein kinase pathway activation. Previous in vitro evidence showed that PDE4 inhibition induced death in NRASQ61mut melanoma cells and such a strategy may thus be a relevant therapeutic option in those cases with no molecular targeted therapies approved to date. In this study, we generated patient-derived xenografts (PDX) from two NRASQ61mut melanoma lesions. We performed ex vivo histoculture drug response assays and in vivo experiments. A significant ex vivo inhibition of proliferation with the combination of roflumilast+cobimetinib was observed compared to dimethyl sulfoxide control in both models (51 and 67%). This antiproliferative effect was confirmed in vivo for PDX-1 with a 56% inhibition of tumor growth. To decipher molecular mechanisms underlying this effect, we performed transcriptomic analyses and revealed a decrease in MKI67, RAF1 and CCND1 expression under bitherapy. Our findings strengthen the therapeutic interest of PDE4 inhibitors and support further experiments to evaluate this approach in metastatic melanoma.

Targeting PDE4A for therapeutic potential: exploiting drug repurposing approach through virtual screening and molecular dynamics

cAMP-specific 3',5'-cyclic phosphodiesterase 4 A (PDE4A) holds a pivotal role in modulating intracellular levels of cyclic adenosine monophosphate (cAMP). Targeting PDE4A with novel therapeutic agents shows promise in addressing neurological disorders (e.g. Alzheimer's and Parkinson's diseases), mood disorders (depression, anxiety), inflammatory conditions (asthma, chronic obstructive pulmonary disease), and even cancer. In this study, we present a comprehensive approach that integrates virtual screening and molecular dynamics (MD) simulations to identify potential inhibitors of PDE4A from the existing pool of FDA-approved drugs. The initial compound selection was conducted focusing on binding affinity scores, which led to the identification of several high-affinity compounds with potential PDE4A binding properties. From the refined selection process, two promising compounds, Fluspirilene and Dihydroergocristine, emerged as strong candidates, displaying substantial affinity and specificity for the PDE4A binding site. Interaction analysis provided robust evidence of their binding capabilities. To gain deeper insights into the dynamic behavior of Fluspirilene and Dihydroergocristine in complex with PDE4A, we conducted 300 ns MD simulations, principal components analysis (PCA), and free energy landscape (FEL) analysis. These analyses revealed that Fluspirilene and Dihydroergocristine binding stabilized the PDE4A structure and induced minimal conformational changes, highlighting their potential as potent binders. In conclusion, our study systematically explores repurposing existing FDA-approved drugs as PDE4A inhibitors through a comprehensive virtual screening pipeline. The identified compounds, Fluspirilene and Dihydroergocristine, exhibit a strong affinity for PDE4A, displaying characteristics that support their suitability for further development as potential therapeutic agents for conditions associated with PDE4A dysfunction.Communicated by Ramaswamy H. Sarma.

Comorbidities in COPD: Current and Future Treatment Challenges

Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition, primarily characterized by the presence of a limited airflow, due to abnormalities of the airways and/or alveoli, that often coexists with other chronic diseases such as lung cancer, cardiovascular diseases, and metabolic disorders. Comorbidities are known to pose a challenge in the assessment and effective management of COPD and are also acknowledged to have an important health and economic burden. Local and systemic inflammation have been proposed as having a potential role in explaining the association between COPD and these comorbidities. Considering that the number of patients with COPD is expected to rise, understanding the mechanisms linking COPD with its comorbidities may help to identify new targets for therapeutic purposes based on multi-dimensional assessments.

PDE4 Phosphodiesterases in Cardiovascular Diseases: Key Pathophysiological Players and Potential Therapeutic Targets

3',5'-cyclic adenosine monophosphate (cAMP) is a second messenger critically involved in the control of a myriad of processes with significant implications for vascular and cardiac cell function. The temporal and spatial compartmentalization of cAMP is governed by the activity of phosphodiesterases (PDEs), a superfamily of enzymes responsible for the hydrolysis of cyclic nucleotides. Through the fine-tuning of cAMP signaling, PDE4 enzymes could play an important role in cardiac hypertrophy and arrhythmogenesis, while it decisively influences vascular homeostasis through the control of vascular smooth muscle cell proliferation, migration, differentiation and contraction, as well as regulating endothelial permeability, angiogenesis, monocyte/macrophage activation and cardiomyocyte function. This review summarizes the current knowledge and recent advances in understanding the contribution of the PDE4 subfamily to cardiovascular function and underscores the intricate challenges associated with targeting PDE4 enzymes as a therapeutic strategy for the management of cardiovascular diseases.

Stasis Dermatitis: The Burden of Disease, Diagnosis, and Treatment

Stasis dermatitis (SD), an inflammatory dermatosis occurring on the lower extremities, is a cutaneous manifestation of chronic venous insufficiency (CVI). SD is associated with a significant burden of disease. Symptoms such as pain, swelling, and itching can be debilitating for patients, leading to poor sleep, loss of mobility, and the inability to perform daily activities, and can interfere with work and leisure activities. Moreover, SD is a progressive disease with serious secondary complications such as ulcerations, which increase the patients' morbidity, reduce their quality of life, and increase health care burden. Challenges in diagnosing patients may have both short- and long-term sequalae for the patients due to unnecessary treatment and management. In addition, misdiagnosis may result in hospitalizations, placing additional burden on health care professionals in terms of time and financial burden on the health care system. Compression therapy and leg elevation represent the mainstay of treatment for CVI; however, it is also difficult to self-manage, which places a substantial burden on patients and caregivers. Moreover, compression therapy may cause discomfort and exacerbate itching. Subsequent nonadherence may result in disease progression that places additional burden on the physicians who manage these patients and the health care system in terms of resources required and costs incurred. A large proportion of patients with SD develop allergic contact dermatitis because of innate immune signals and altered skin barrier predisposing to sensitization to topical prescriptions, over-the-counter medications, and compression devices used to treat SD. Other than topical corticosteroids, there are no approved pharmacological options to treat inflammation in SD.

Novel pharmacological approaches in abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a severe vascular disease and a major public health issue with an unmet medical need for therapy. This disease is featured by a progressive dilation of the abdominal aorta, boosted by atherosclerosis, ageing, and smoking as major risk factors. Aneurysm growth increases the risk of aortic rupture, a life-threatening emergency with high mortality rates. Despite the increasing progress in our knowledge about the etiopathology of AAA, an effective pharmacological treatment against this disorder remains elusive and surgical repair is still the unique available therapeutic approach for high-risk patients. Meanwhile, there is no medical alternative for patients with small aneurysms but close surveillance. Clinical trials assessing the efficacy of antihypertensive agents, statins, doxycycline, or anti-platelet drugs, among others, failed to demonstrate a clear benefit limiting AAA growth, while data from ongoing clinical trials addressing the benefit of metformin on aneurysm progression are eagerly awaited. Recent preclinical studies have postulated new therapeutic targets and pharmacological strategies paving the way for the implementation of future clinical studies exploring these novel therapeutic strategies. This review summarises some of the most relevant clinical and preclinical studies in search of new therapeutic approaches for AAA.

Prostaglandin E2 (PGE2) and Roflumilast Involvement in IPF Progression

The ECM propagates processes in idiopathic pulmonary fibrosis (IPF), leading to progressive lung scarring. We established an IPF-conditioned matrix (IPF-CM) system as a platform for testing drug candidates. Here, we tested the involvement of a PGE2 and PDE4 inhibitor, Roflumilast, in the IPF-CM system. Primary normal/IPF tissue-derived human lung fibroblasts (N/IPF-HLFs) were cultured on Matrigel and then removed to create the IPF-CM. N-HLFs were exposed to the IPF-CM/N-CM with/without PGE2 (1 nM) and Roflumilast (1 µM) for 24 h. The effect of the IPF-CM on cell phenotype and pro-fibrotic gene expression was tested. In addition, electronic records of 107 patients with up to 15-year follow-up were retrospectively reviewed. Patients were defined as slow/rapid progressors using forced vital capacity (FVC) annual decline. Medication exposure was examined. N-HLFs cultured on IPF-CM were arranged in large aggregates as a result of increased proliferation, migration and differentiation. A PGE2 and Roflumilast combination blocked the large aggregate formation induced by the IPF-CM (p < 0.001) as well as cell migration, proliferation, and pro-fibrotic gene expression. A review of patient records showed that significantly more slow-progressing patients were exposed to NSAIDs (p = 0.003). PGE2/PDE4 signaling may be involved in IPF progression. These findings should be further studied.

cAMP: A master regulator of cadherin-mediated binding in endothelium, epithelium and myocardium

Regulation of cadherin-mediated cell adhesion is crucial not only for maintaining tissue integrity and barrier function in the endothelium and epithelium but also for electromechanical coupling within the myocardium. Therefore, loss of cadherin-mediated adhesion causes various disorders, including vascular inflammation and desmosome-related diseases such as the autoimmune blistering skin dermatosis pemphigus and arrhythmogenic cardiomyopathy. Mechanisms regulating cadherin-mediated binding contribute to the pathogenesis of diseases and may also be used as therapeutic targets. Over the last 30 years, cyclic adenosine 3',5'-monophosphate (cAMP) has emerged as one of the master regulators of cell adhesion in endothelium and, more recently, also in epithelial cells as well as in cardiomyocytes. A broad spectrum of experimental models from vascular physiology and cell biology applied by different generations of researchers provided evidence that not only cadherins of endothelial adherens junctions (AJ) but also desmosomal contacts in keratinocytes and the cardiomyocyte intercalated discs are central targets in this scenario. The molecular mechanisms involve protein kinase A- and exchange protein directly activated by cAMP-mediated regulation of Rho family GTPases and S665 phosphorylation of the AJ and desmosome adaptor protein plakoglobin. In line with this, phosphodiesterase 4 inhibitors such as apremilast have been proposed as a therapeutic strategy to stabilize cadherin-mediated adhesion in pemphigus and may also be effective to treat other disorders where cadherin-mediated binding is compromised.

Pretreatment with tadalafil attenuates cardiotoxicity induced by combretastatin A4 disodium phosphate in rats

Combretastatin A4 disodium phosphate (CA4DP) is a prodrug of combretastatin A4 (CA4), a microtubule-disassembling agent that exhibits antitumor effects by inhibiting tumor cell proliferation and inducing morphological changes and apoptosis in vascular endothelial cells in tumors. However, cardiotoxicity induced by ischemia and hypertension is a severe adverse event. In this study, we focused on the fact that phosphodiesterase (PDE) 5 inhibitors dilate the heart and peripheral blood vessels and aimed to investigate whether co-administration of tadalafil, a PDE5 inhibitor, can attenuate cardiotoxicity without altering the antitumor effect of CA4DP. To investigate cardiotoxicity, CA4DP and/or tadalafil were administered to rats, and blood pressure, echocardiography, histopathology, and cGMP concentration in the myocardium were examined. Administration of CA4DP increased systolic blood pressure, decreased cardiac function, lowered cGMP levels in the myocardium, and led to necrosis of myocardial cells. Co-administration of tadalafil attenuated these CA4DP-induced changes. To investigate the antitumor effect, canine mammary carcinoma cell lines (CHMp-13a) and human umbilical vein endothelial cells were cultured with CA4 and/or tadalafil, and cell proliferation and endothelial vascular tube disruption were examined. CHMp-13a cells were transplanted into nude mice and treated with CA4DP and/or tadalafil. CA4-induced inhibition of cell proliferation and disruption of the endothelial vascular tube were not affected by co-treatment with tadalafil, and the antitumor effects of CA4DP in xenograft mice were not reduced by co-administration of tadalafil. These results revealed that myocardial damage induced by CA4DP was attenuated by co-administration of tadalafil while maintaining antitumor efficacy.

PDE4 inhibitors for disease therapy: advances and future perspective

The PDE4 enzyme family is specifically responsible for hydrolyzing cAMP and plays a vital role in regulating the balance of second messengers. As a crucial regulator in signal transduction, PDE4 has displayed promising pharmacological targets in a variety of diseases, for which its inhibitors have been used as a therapeutic strategy. This review provides a comprehensive summary of the development of PDE4 inhibitors in the past few years, along with the structure, clinical and research progress of multiple inhibitors of PDE4, focusing on the research and development strategies of PDE4 inhibitors. We hope our analysis will provide a significant reference for the future development of new PDE4 inhibitors.

Roflumilast ameliorates ovariectomy-induced depressive-like behavior in rats via activation of AMPK/mTOR/ULK1-dependent autophagy pathway

AIMS

Roflumilast, a well-known phosphodiesterase-4 (PDE-4) inhibitor, possess an anti-inflammatory activity with approved indications in chronic obstructive pulmonary disease. This study aimed to evaluate the neuroprotective role of roflumilast in ovariectomy (OVX)-induced depressive-like behavior in female rats and to shed light on a potential autophagy enhancing effect.

MAIN METHODS

Rats were randomly divided into four groups: sham, OVX, OVX + roflumilast (1 mg/kg, p.o), and OVX + roflumilast + chloroquine (CQ) (50 mg/kg, i.p). Drugs were administered for 4 weeks starting 2 weeks after OVX.

KEY FINDINGS

Roflumilast improved the depressive-like behaviors observed in OVX rats as evidenced by decreasing both forced swimming and open field immobility times while, increasing % sucrose preference and number of open field crossed squares. Histopathological analysis provides further evidence of roflumilast's beneficial effects, demonstrating that roflumilast ameliorated the neuronal damage caused by OVX. Roflumilast antidepressant potential was mediated via restoring hippocampal cAMP and BDNF levels as well as down-regulating PDE4 expression. Moreover, roflumilast revealed anti-inflammatory and anti-apoptotic effects via hindering TNF-α level and diminishing Bax/Bcl2 ratio. Roflumilast restored the autophagic function via up-regulation of p-AMPK, p-ULK1, Beclin-1 and LC3II/I expression, along with downregulation of P62 level and p-mTOR protein expression. The autophagy inhibitor CQ was used to demonstrate the suggested pathway.

SIGNIFICANCE

The present study revealed that roflumilast showed an anti-depressant activity in OVX female rats via turning on AMPK/mTOR/ULK1-dependent autophagy pathway; and neurotrophic, anti-inflammatory, and anti-apoptotic activities. Roflumilast could offer a more secure alternative to hormone replacement therapy for postmenopausal depression treatment.

Artesunate inhibits PDE4 leading to intracellular cAMP accumulation, reduced ERK/MAPK signaling, and blockade of influenza A virus vRNP nuclear export

Influenza A viruses (IAV) have been a major cause of mortality. Given the potential for future deadly pandemics, effective drugs are needed for the treatment of severe influenzas, such as those caused by H5N1 IAV. The anti-malaria drugs artemisinin and its derivates, including artesunate (AS), have been reported to have broad antiviral activities. Here, we showed AS's antiviral activity against H5N1, H1N1, H3N2 and oseltamivir-resistant influenza A(H1N1)virus in vitro. Moreover, we showed that AS treatment significantly protected mice from lethal challenges with H1N1 and H5N1 IAV. Strikingly, the combination of AS and peramivir treatment significantly improved survival outcomes compared to their monotherapy with either AS or peramivir. Furthermore, we demonstrated mechanistically that AS affected the later stages of IAV replication and limited nuclear export of viral ribonucleoprotein (vRNP) complexes. In A549 cells, we demonstrated for the first time that AS treatment induced cAMP accumulation via inhibiting PDE4, and consequently reduced ERK phosphorylation and blocked IAV vRNP export, and thus suppressed IAV replication. These AS's effects were reversed by the pre-treatment with a cAMP inhibitor SQ22536. Our findings suggest that AS could serve as a novel IAV inhibitor by interfering vRNP nuclear export to prevent and treat IAV infection.

Narrative Review of the Pathogenesis of Stasis Dermatitis: An Inflammatory Skin Manifestation of Venous Hypertension

INTRODUCTION

Stasis dermatitis (SD), also known as venous dermatitis, is a form of inflammatory dermatitis of the lower extremities that typically occurs in older individuals and represents a cutaneous manifestation of venous hypertension. Venous hypertension (also known as sustained ambulatory venous pressure) is most often due to retrograde blood flow, which occurs due to calf muscle pump failure. This failure is most commonly secondary to incompetent venous valves, valve destruction, or obstruction of the venous system. Many of the common symptoms associated with SD are caused by inflammatory processes.

METHODS

This review summarizes the pathogenesis and key role of inflammation in SD by reviewing inflammatory biomarkers associated with SD. The literature was selected though a high-level PubMed search focusing on keywords relating to inflammation associated with SD.

RESULTS

Venous reflux at the lower extremities causes venous hypertension, which leads to chronic venous insufficiency. High venous pressure due to venous hypertension promotes the local accumulation and extravasation of inflammatory cells across the vascular endothelium. Leukocyte trapping in the microcirculation and perivascular space is associated with trophic skin changes. Cell adhesion molecules are linked with the perpetuated influx of activated leukocytes into inflammatory sites. Here, inflammatory cells may influence the remodeling of the extracellular matrix by inducing the secretion of proteinases such as matrix metalloproteinases (MMPs). The increased expression of MMPs is associated with the formation of venous leg ulcers and lesions. Phosphodiesterase 4 activity has also been shown to be elevated in individuals with inflammatory dermatoses compared to healthy individuals.

DISCUSSION

Because inflammation is a key driver of the signs and symptoms of SD, several of the highlighted biomarkers of inflammation represent potential opportunities to target and interrupt molecular pathways of cutaneous inflammation and, therefore, remediate the signs and symptoms of SD.

CONCLUSION

Understanding the pathogenesis of SD may help clinicians identify drivers of inflammation to use as potential targets for the development of new treatment options.

Recent advances of Phosphodiesterase 4B in cancer

INTRODUCTION

Phosphodiesterase 4B (PDE4B) is a crucial enzyme in the phosphodiesterases (PDEs), acting as a regulator of cyclic adenosine monophosphate (cAMP). It is involved in cancer process through PDE4B/cAMP signaling pathway. Cancer occurs and develops with the regulation of PDE4B in the body, suggesting that PDE4B is a promising therapeutic target.

AREAS COVERED

This review covereed the function and mechanism of PDE4B in cancer. We summarized the possible clinical applications of PDE4B, and highlighted the possible ways to develop clinical applications of PDE4B inhibitors. We also discussed some common PDEs inhibitors, and expected the development of combined targeting PDE4B and other PDEs drugs in the future.

EXPERT OPINION

The existing research and clinical data can strongly prove the role of PDE4B in cancer. PDE4B inhibition can effectively increase cell apoptosis, inhibit cell proliferation, transformation, migration, etc., indicating that PDE4B inhibition can effectively inhibit the development of cancer. Other PDEs may antagonize or coordinate this effect. As for the further study on the relationship between PDE4B and other PDEs in cancer, it is still a challenge to develop multi-targeted PDEs inhibitors.

Intermittent treatment with Apremilast, a phosphodiesterase-4 inhibitor, ameliorates Alzheimer's-like pathology and symptoms through multiple targeting actions in aged T2D rats

BACKGROUND

Apremilast (Apre), a novel phosphodiesterase-4 (PDE4) inhibitor, has been shown to have anti-inflammatory, immunomodulator, neuroprotective and senolytic properties, therefore, Apre like other PDE4 inhibitors may be a promising candidate for treatment of Alzheimer's disease (AD).

OBJECTIVE

To evaluate the effectiveness of Apre on Alzheimer's like pathology and symptoms in an animal model.

METHODS

The effects of Apre and cilostazol, a reference drug, on the behavioral, biochemical, and pathological features of Alzheimer's disease induced by a high-fat/high-fructose diet combined with low-dose streptozotocin (HF/HFr/l-STZ) were investigated.

RESULT

Apre 5 mg/kg IP/day for 3 consecutive days per week for 8 weeks attenuated memory and learning deficits tested by novel object recognition, Morris water maze and passive avoidance tests. Apre treatment significantly decreased the number of degenerating cells, and abnormal suppression of gene expression of AMPA and NMDA receptor subunits in the cortex and hippocampus of the AD rat model compared to rats that received vehicle. A significant decrease in elevated levels of hippocampal amyloid beta, tau-positive cell count, cholinesterase activity, and hippocampal caspase-3, a biomarker of neurodegeneration, was also observed after treatment with Apre in AD rats compared to rats that received placebo. Furthermore, a significant decrease in pro-inflammatory cytokines, oxidative stress, insulin resistance and GSK-3 was demonstrated in AD aged rats treated by Apre.

CONCLUSION

Our findings demonstrate that intermittent treatment with Apre can enhance cognitive function in HF/HFr/l-STZ rats which may be related to decreased pro-inflammatory cytokines, oxidative stress, insulin resistance and GSK-3β.

Pharmacological Management of Obesity in Patients with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age. A substantial proportion of patients with PCOS are either overweight or obese, and excess body weight aggravates the hormonal, reproductive and metabolic manifestations of PCOS. In recent years, several studies evaluated the role of various pharmacological agents in the management of obesity in this population. Most reports assessed glucagon-like peptide-1 receptor agonists and showed a substantial reduction in body weight. More limited data suggest that sodium-glucose cotransporter-2 inhibitors and phosphodiesterase-4 inhibitors might also be effective in the management of obesity in these patients. In the present review, we discuss the current evidence on the safety and efficacy of these agents in overweight and obese patients with PCOS.

Stasis Dermatitis: An Overview of Its Clinical Presentation, Pathogenesis, and Management

Stasis dermatitis is a chronic inflammatory skin disease of the lower extremities. It typically occurs in older individuals and is the cutaneous manifestation of venous hypertension caused by venous reflux. Such retrograde venous blood flow is the result of incompetent venous valves, valve destruction, or venous obstruction. Stasis dermatitis is eczematous. The associated impairment of venous valves may cause swelling of the legs, leading to serious conditions including venous ulcerations. Diagnosis can be challenging because of its clinical resemblance to other skin conditions and poor clinical recognition by physicians. The cornerstones of stasis dermatitis treatment are compression therapy to ameliorate pain and swelling, topical treatments to alleviate secondary skin changes, and interventional treatment options to correct the underlying causes of venous reflux. Given the central role of inflammation of the lower extremities in driving the cutaneous changes characteristic of stasis dermatitis, new therapeutic approaches that target the inflammation are under clinical evaluation in patients with stasis dermatitis.

The regulatory role of PDE4B in the progression of inflammatory function study

Inflammation is a response of the body to external stimuli (eg. chemical irritants, bacteria, viruses, etc.), and when the stimuli are persistent, they tend to trigger chronic inflammation. The presence of chronic inflammation is an important component of the tumor microenvironment produced by a variety of inflammatory cells (eg. macrophages, neutrophils, leukocytes, etc.). The relationship between chronic inflammation and cancer development has been widely accepted, and chronic inflammation has been associated with the development of many cancers, including chronic bronchitis and lung cancer, cystitis inducing bladder cancer. Moreover, chronic colorectitis is more likely to develop into colorectal cancer. Therefore, the specific relationship and cellular mechanisms between inflammation and cancer are a hot topic of research. Recent studies have identified phosphodiesterase 4B (PDE4B), a member of the phosphodiesterase (PDEs) protein family, as a major cyclic AMP (cAMP) metabolizing enzyme in inflammatory cells, and the therapeutic role of PDE4B as chronic inflammation, cancer. In this review, we will present the tumors associated with chronic inflammation, and PDE4B potential clinical application.

The Complexity and Multiplicity of the Specific cAMP Phosphodiesterase Family: PDE4, Open New Adapted Therapeutic Approaches

Cyclic nucleotides (cAMP, cGMP) play a major role in normal and pathologic signaling. Beyond receptors, cyclic nucleotide phosphodiesterases; (PDEs) rapidly convert the cyclic nucleotide in its respective 5′-nucleotide to control intracellular cAMP and/or cGMP levels to maintain a normal physiological state. However, in many pathologies, dysregulations of various PDEs (PDE1-PDE11) contribute mainly to organs and tissue failures related to uncontrolled phosphorylation cascade. Among these, PDE4 represents the greatest family, since it is constituted by 4 genes with multiple variants differently distributed at tissue, cellular and subcellular levels, allowing different fine-tuned regulations. Since the 1980s, pharmaceutical companies have developed PDE4 inhibitors (PDE4-I) to overcome cardiovascular diseases. Since, they have encountered many undesired problems, (emesis), they focused their research on other PDEs. Today, increases in the knowledge of complex PDE4 regulations in various tissues and pathologies, and the evolution in drug design, resulted in a renewal of PDE4-I development. The present review describes the recent PDE4-I development targeting cardiovascular diseases, obesity, diabetes, ulcerative colitis, and Crohn’s disease, malignancies, fatty liver disease, osteoporosis, depression, as well as COVID-19. Today, the direct therapeutic approach of PDE4 is extended by developing allosteric inhibitors and protein/protein interactions allowing to act on the PDE interactome.

More than a random association between chronic obstructive pulmonary disease and psoriatic arthritis: shared pathogenic features and implications for treatment

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic inflammatory condition characterized by skin and joints involvement, and with a great burden of comorbidity that could affect the choice of treatment. Chronic obstructive pulmonary disease (COPD) is one of the primary causes of morbidity and mortality. Medical therapy can improve symptoms and the frequency and severity of exacerbations. A variety of evidence showed an increasing association between COPD and PsA.

AREAS COVERED

Psoriatic disease and COPD appear to have a possible pathophysiologic link. The inhibition of intracellular molecules responsible for pro-inflammatory responses could be a therapeutic approach for both psoriatic diseases and COPD. Inhibitors of phosphodiesterase 4 (PDE-4) were developed to treat chronic inflammatory conditions such as psoriasis, PsA and COPD. Roflumilast has been used to treat COPD and asthma, while Apremilast to treat psoriasis and PsA. Given the efficacy and safety of these treatments, we can speculate that blocking PDE-4 might also provide clinical benefits in patients with co-existing COPD and PsA.

EXPERT OPINION

This hypothesis could offer the opportunity to screen patients for both diseases. Furthermore, this approach would increase the involvement of other specialists in the management of PsA, and it would improve the use of a tailored treatment for each patient.