The flavonoid dioclein reduces the production of pro-inflammatory mediators in vitro by inhibiting PDE4 activity and scavenging reactive oxygen species

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.

Ameliorative effect of phosphodiesterase 4 and 5 inhibitors in deoxycorticosterone acetate-salt hypertensive uni-nephrectomized KKAy mice

Diabetic nephropathy (DN) is a leading cause of end-stage renal disease (ESRD). Hypertension increases kidney stress, which deteriorates function, and leads to peripheral renal vascular resistance. Long-term hypoperfusion promotes interstitial fibrosis and glomerular sclerosis, resulting in nephrosclerosis. Although hypertension and DN are frequent ESRD complications, relevant animal models remain unavailable. We generated a deoxycorticosterone acetate (DOCA)-salt hypertensive uni-nephrectomized (UNx) KKA^y mouse model demonstrating hypertension, hyperglycemia, cardiac hypertrophy, kidney failure, increased urinary albumin creatinine ratio (UACR), and increased renal PDE4D and cardiac PDE5A mRNA levels. We hypothesized that the novel PDE4 selective inhibitor, compound A, and PDE5 inhibitor, sildenafil, exhibit nephroprotective, and cardioprotective effects in this new model. Compound A, sildenafil, and the angiotensin II receptor blocker, irbesartan, significantly reduced ventricular hypertrophy and pleural effusion volume. Meanwhile, compound A and sildenafil significantly suppressed the UACR, urinary kidney injury molecule-1, and monocyte chemoattractant protein-1 levels, as well as that of renal pro-fibrotic marker mRNAs, including collagen 1A1, fibronectin, and transforming growth factor-beta (TGF-β). Moreover, compound A significantly suppressed TGF-β-induced pro-fibrotic mRNA expression in vitro in all major kidney lesions, including within the glomerular mesangial region, podocytes, and epithelial region. Hence, PDE4 and PDE5 inhibitors may be promising treatments, in combination with irbesartan, for DN with hypertension as they demonstrate complementary mechanisms.

Animal Models of Inflammation for Screening of Anti-inflammatory Drugs: Implications for the Discovery and Development of Phytopharmaceuticals

Inflammation is one of the common events in the majority of acute as well as chronic debilitating diseases and represent a chief cause of morbidity in today's era of modern lifestyle. If unchecked, inflammation leads to development of rheumatoid arthritis, diabetes, cancer, Alzheimer's disease, and atherosclerosis along with pulmonary, autoimmune and cardiovascular diseases. Inflammation involves a complex network of many mediators, a variety of cells, and execution of multiple pathways. Current therapy for inflammatory diseases is limited to the steroidal and non-steroidal anti-inflammatory agents. The chronic use of these drugs is reported to cause severe adverse effects like gastrointestinal, cardiovascular, and renal abnormalities. There is a massive need to explore new anti-inflammatory agents with selective action and lesser toxicity. Plants and isolated phytoconstituents are promising and interesting sources of new anti-inflammatories. However, drug development from natural sources has been linked with hurdles like the complex nature of extracts, difficulties in isolation of pure phytoconstituents, and the yield of isolated compounds in minute quantities that is insufficient for subsequent lead development. Although various in-vivo and in-vitro models for anti-inflammatory drug development are available, judicious selection of appropriate animal models is a vital step in the early phase of drug development. Systematic evaluation of phytoconstituents can facilitate the identification and development of potential anti-inflammatory leads from natural sources. The present review describes various techniques of anti-inflammatory drug screening with its advantages and limitations, elaboration on biological targets of phytoconstituents in inflammation and biomarkers for the prediction of adverse effects of anti-inflammatory drugs. The systematic approach proposed through present article for anti-inflammatory drug screening can rationalize the identification of novel phytoconstituents at the initial stage of drug screening programs.

Small Molecules for Neural Stem Cell Induction

Generation of induced pluripotent stem cells (iPSCs) from other somatic cells has provided great hopes for transplantation therapies. However, these cells still cannot be used for clinical application due to the low reprogramming and differentiation efficiency beside the risk of mutagenesis and tumor formation. Compared to iPSCs, induced neural stem cells (iNSCs) are easier to terminally differentiate into neural cells and safe; thus, iNSCs hold more opportunities than iPSCs to treat neural diseases. On the other hand, recent studies have showed that small molecules (SMs) can dramatically improve the efficiency of reprogramming and SMs alone can even convert one kind of somatic cells into another, which is much safer and more effective than transcription factor-based methods. In this study, we provide a review of SMs that are generally used in recent neural stem cell induction studies, and discuss the main mechanisms and pathways of each SM.

Therapeutic potentials of natural compounds acting on cyclic nucleotide phosphodiesterase families

Intracellular cyclic AMP and/or cyclic GMP are characterized in the 1960th. These second messengers, hydrolysed specifically by cyclic nucleotide phosphodiesterase (PDE), play a major role in intracellular signalling. Natural products have been a rich source of drug discovery, Theophylline and Methylxanthine originated from tea leaves used for asthma treatment, whereas, Papaverine, a natural isoquinolein originated from Papaver somniferum traditionally used in impotency, altogether as caffeine where firstly described as PDE-inhibiting compounds. Since that time, the knowledge in PDE field has been drastically increased, allowing the design and development of new therapeutic drugs acting against different pathologies in the nanomolar range. During this period some natural compounds have been identified as PDE inhibitors and used in that context to investigate their therapeutic potential effects. The aim of this literature review is to point out the reported data and demonstrating the contribution of natural characterized molecules as PDE inhibitors in various pathologies that can open new fields of research for drug discovery, notably in epigenetic regulation.

Phosphodiesterase-4 inhibitors ameliorates cognitive deficits in deoxycorticosterone acetate induced hypertensive rats via cAMP/CREB signaling system

Phosphodiesterase-4 (PDE-4) inhibitors promote memory by blocking the degradation of cAMP. Existing evidence also shows that neuronal survival and plasticity are dependent on the phosphorylation of cAMP-response element-binding protein. In this regard, PDE-4 inhibitors have also been shown to reverse pharmacologically and genetically induced memory impairment in animal models. In the present study, the authors examined the effect of both rolipram and roflumilast (PDE-4 inhibitors) on the impairment of learning and memory observed in hypertensive rats. Deoxycorticosterone acetate (DOCA) salt hypertensive model was used to induce learning and memory deficits. The mRNA expression of different PDE-4 subtypes along with the protein levels of pCREB and BDNF in the hippocampus was quantified. Systolic blood pressure was significantly increased in DOCA salt hypertensive rats when compared to sham operated rats. This effect was reversed by clonidine, an α2 receptor agonist, while PDE-4 inhibitors did not. PDE-4 inhibitors significantly improved the time-induced memory deficits in object recognition task (ORT). In DOCA salt hypertensive rats, the gene expression of PDE-4B and PDE-4D was significantly increased. Furthermore, both pCREB and BDNF showed decreased levels of expression in hypertensive rats in comparison to sham operated rats. Repeated administration of PDE-4 inhibitors significantly decreased both PDE-4B and PDE-4D with an increase in the expression of pCREB and BDNF in hypersensitive rats. Also, rolipram, roflumilast and roflumilast N-oxide showed a linear increase in the plasma and brain concentrations after ORT. Our present findings suggested that PDE-4 inhibitors ameliorate hypertension-induced learning impairment via cAMP/CREB signaling that regulates BDNF expression downstream in the rat hippocampus.

Multitargeted protective effect of Abacopteris penangiana against carrageenan-induced chronic prostatitis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Abacopteris penangiana (Hook.) Ching (AP) is traditionally used in Chinese medicine to promote blood circulation, remove blood stasis and dampness and for the treatment of edema and inflammation. In order to further support and develop the traditional use of Abacopteris penangiana as Chinese folk medicine, the aim of this study is to investigate the protective effect of the total flavanol glycosides (TFA) from AP and its acid hydrolysate (AHT) on chronic non-bacterial prostatitis (CNP) by measuring the levels of oxidative stress and inflammatory responses in rats.

MATERIALS AND METHODS

First, the antioxidant and anti-inflammatory activities of AHT and TFA were investigated. Then the experimental chronic non-bacterial prostatitis was induced by carrageenan. The prostate index (PI) and prostate specific antigen (PSA) were determined. The activities of AHT and TFA on inhibiting free radicals and oxidative stress were investigated. Subsequently, the degree of chronic inflammatory cell infiltrates, acinar changes and interstitial fibrosis were evaluated by histopathological examination. In addition, the relative inflammatory factors, tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), cyclooxygenase-2 (COX-2), prostaglandin E2 (PEG2), transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) were measured. Finally, the prostatic expression of nuclear transcription factor-κB (NF-κB) was determined by immunohistochemistry and western blot analysis.

RESULTS

The whole results showed that AHT and TFA had strong antioxidant and anti-inflammatory activities. In CNP model, AHT and TFA successfully decreased PI and PSA. The activities of antioxidant enzymes in AHT or TFA group were enhanced. Additionally, a morphometric analysis of the prostate gland of AHT or TFA treated rats demonstrated a significant reduction in chronic inflammatory cell infiltrates and interstitial fibrosis compared to model group. The reduced values of TNF-α, IL-1β, COX-2, PEG2, inducible nitric oxide synthase (iNOS) and nitric oxide (NO) were observed both in AHT and TFA treated groups. Moreover, the levels of TGF-β1 and CTGF in AHT and TFA treated groups were significantly decreased along with the alleviation of the inflammatory state of the prostate gland. Besides, the prostatic expression of NF-κB was inhibited.

CONCLUSIONS

These results suggest that AHT and TFA have anti-prostatitis properties via inhibiting oxidative stress, NF-κB dependent pro-inflammatory cytokines, fibrosis-related factors and antinociceptive activity. Hence, AP represents a potential herb for the treatment of prostatitis.

Phosphodiesterase-4 inhibitor therapy for lung diseases

Phosphodiesterases (PDEs) are a superfamily of enzymes that catalyze the breakdown of cAMP and/or cyclic guanosine monophosphate (GMP) to their inactive form. PDE4 is the main selective cAMP-metabolizing enzyme in inflammatory and immune cells. Because PDE4 is highly expressed in leukocytes and other inflammatory cells involved in the pathogenesis of inflammatory lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD), inhibition of PDE4 has been predicted to have an antiinflammatory effect and thus therapeutic efficacy. The limited and inconsistent efficacy and side effects of the early compounds made their further development less desirable in asthma, given the excellent efficacy/tolerability ratio of inhaled steroids. The lack of effective antiinflammatory drug treatment for COPD has thus shifted the interest in development toward COPD. Roflumilast, the only PDE4 inhibitor that has reached the market because of the good efficacy/tolerability ratio, is recommended for patients with COPD with severe airflow limitation, symptoms of chronic bronchitis, and a history of exacerbations, whose disease is not adequately controlled by long-acting bronchodilators. Albeit safe, it maintains significant side effects (diarrhea, nausea, weight loss) that make it intolerable in some patients. Future developments of PDE4 inhibitors include extended indications of roflumilast (1) in patients with COPD, and (2) in other respiratory (e.g., asthma) and nonrespiratory chronic inflammatory/metabolic conditions (e.g., diabetes), as well as (3) the development of new molecules with PDE4 inhibitory properties with an improved efficacy/tolerability profile.

Pharmaceutical properties and toxicology of Dioclea grandiflora

CONTEXT

Since the beginning of civilization, herbal medicines have been an important source for human beings to treat their ailments. Despite the large number of synthetic remedies available in the market, the use of plants is seen as a great challenge in the search for new substances endowed with therapeutic properties. One example is Dioclea grandiflora Mart. ex Benth. (Leguminosae) employed in traditional medicine to treat prostate disorders and kidney stones.

OBJECTIVES

This work presents a brief overview of D. grandiflora, including a description of the plant, its chemical composition and pharmacological properties.

METHODS

This review gathers information available in the scientific literature compiled from databases such as Science Direct, PubMed, Dr. Dukes Phytochemical and Ethnobotany, Missouri Botanical Garden and The International Plant Names Index.

RESULTS

The information found in the literature showed that flavonoids are the major constituents of D. grandiflora that account for most of the pharmacological properties so far disclosed. Several studies have revealed that D. grandiflora possesses antinociceptive, cardiovascular, antioxidant and anti-inflammatory activities.

CONCLUSION

Research shows that D. grandiflora is a potential source of compounds pertaining medicinal applications. It provides an interesting subject in the search for new drugs of natural origin.

Phosphodiesterase 4-targeted treatments for autoimmune diseases

Advancements in phosphodiesterase (PDE)-targeted therapies have shown promise in recent years for treating patients with a variety of autoimmune diseases. This review summarizes the development of PDE4 inhibitors and the associated literature with a focus on treatments for autoimmune diseases. After the initial investigations of the prototypic PDE inhibitor, rolipram, more selective inhibitors targeting the PDE4 isozyme have been developed. With phase II and phase III clinical trials currently underway to evaluate the safety and efficacy of the latest generation of PDE4 inhibitors, namely apremilast, a new class of treatments may be around the corner for patients suffering from chronic, autoimmune diseases.