Phosphodiestrase-1 and 4 inhibitors ameliorate liver fibrosis in rats: Modulation of cAMP/CREB/TLR4 inflammatory and fibrogenic pathways

Rationale for phosphodiesterase-4 inhibition as a treatment strategy for interstitial lung diseases associated with rheumatic diseases

Interstitial lung disease (ILD) associated with rheumatoid arthritis or with connective tissue diseases such as systemic sclerosis can be collectively named systemic autoimmune rheumatic disease-associated ILDs (SARD-ILDs) or rheumatic musculoskeletal disorder-associated ILDs. SARD-ILDs result in substantial morbidity and mortality, and there is a high medical need for effective therapies that target both fibrotic and inflammatory pathways in SARD-ILD. Phosphodiesterase 4 (PDE4) hydrolyses cyclic AMP, which regulates multiple pathways involved in inflammatory processes. PDE4 is overexpressed in peripheral blood monocytes from patients with inflammatory diseases. However, clinical data on pan-PDE4 inhibition in fibrotic conditions are lacking. The PDE4B subtype is highly expressed in the brain, lungs, heart, skeletal muscle and immune cells. As such, inhibition of PDE4B may be a novel approach for fibrosing ILDs such as idiopathic pulmonary fibrosis (IPF) and SARD-ILD. Preclinical data for PDE4B inhibition have provided initial evidence of both anti-inflammatory and antifibrotic activity, with reduced potential for gastrointestinal toxicity compared with pan-PDE4 inhibitors. In a proof-of-concept phase II trial in patients with IPF, nerandomilast (BI 1015550), the only PDE4B inhibitor currently in clinical development, prevented a decline in lung function over 12 weeks compared with placebo. The potential clinical benefit of PDE4B inhibition is now being investigated in the phase III setting, with two trials evaluating nerandomilast in patients with IPF (FIBRONEER-IPF) or with progressive pulmonary fibrosis other than IPF (FIBRONEER-ILD). Here, we review the preclinical and clinical data that provide rationale for PDE4B inhibition as a treatment strategy in patients with SARD-ILD.

Roflumilast ameliorates GAN diet-induced non-alcoholic fatty liver disease by reducing hepatic steatosis and fibrosis in ob/ob mice

Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent progressive liver disease. Currently, there is only one drug for NAFLD treatment, and the options are limited. Phosphodiesterase-4 (PDE-4) inhibitors have potential in treating NAFLD. Therefore, this study aims to investigate the effect of roflumilast on NAFLD. Here, we fed ob/ob mice to induce the NAFLD model by GAN diet. Roflumilast (1 mg/kg) was administered orally once daily. Semaglutide (20 nmol/kg), used as a positive control, was injected subcutaneously once daily. Our findings showed that roflumilast has beneficial effects on NAFLD. Roflumilast prevented body weight gain and improved lipid metabolism in ob/ob-GAN NAFLD mice. In addition, roflumilast decreased hepatic steatosis by down-regulating the expression of hepatic fatty acid synthesis genes (SREBP1c, FASN, and CD36) and improving oxidative stress. Roflumilast not only reduced liver injury by decreasing serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, but also ameliorated hepatic inflammation by reducing the gene expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6). Roflumilast lessened liver fibrosis by inhibiting the expression of fibrosis mRNA (TGFβ1, α-SMA, COL1a1, and TIMP-1). Collectively, roflumilast could ameliorate NAFLD, especially in reducing hepatic steatosis and fibrosis. Our findings suggested a PDE-4 inhibitor roflumilast could be a potential drug for NAFLD.

The circAno6/miR-296-3p/TLR4 signaling axis mediates the inflammatory response to induce the activation of hepatic stellate cells

BACKGROUND

Circular RNA (circRNA) is a novel functional non-coding RNA(ncRNA) that plays a role in the occurrence and development of multiple human liver diseases, including liver fibrosis (LF). LF is a reversible repair response after liver injury, and the activation of hepatic stellate cells (HSCs) is the core event. However, the regulatory mechanisms by which circRNAs induce the activation of HSCs in LF are still poorly understood. The circAno6/miR-296-3p/toll-like receptor 4 (TLR4) signaling axis that mediates the inflammatory response and causes the activation of HSCs was investigated in this study.

METHODS

First, a circAno6 overexpression plasmid and small interfering RNA were transfected into cells to determine whether circAno6 can affect the function of HSCs. Second, real-time quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), western blotting (WB) and immunofluorescence (IF) were used to detect the effects of circAno6 plasmid/siRNA transfection on HSC activation indices, inflammatory markers and the circAno6/miR-296-3p/TLR4 signaling axis. The subcellular position of circAno6 was then examined by nucleo-cytoplasmic separation and fluorescence in situ hybridization (FISH). Finally, a luciferase reporter gene assay was used to identify the relationship between circAno6 and miR-296-3p as well as the relationship between miR-296-3p and TLR4.

RESULTS

CircAno6 was considerably upregulated in HSCs and positively correlated with cell proliferation and alpha-smooth muscle actin (α-SMA), collagen I, NOD-likereceptorthermalproteindomainassociatedprotein 3 (NLRP3), interleukin-1β (IL-1β) and interleukin-18 (IL-18) expression. Overexpression of circAno6 increased the inflammatory response and induced HSC activation, whereas interference resulted in the opposite effects. FISH experiments revealed the localization of circAno6 in the cytoplasm. Then, a double luciferase reporter assay confirmed that miR-296-3p significantly inhibited luciferase activity in the circAno6-WT and TLR4-WT groups.

CONCLUSION

This study suggests that circAno6 and miR-296-3p/TLR4 may form a regulatory axis and regulate the inflammatory response, which in turn induces HSC activation. Targeting circAno6 may be a potential therapeutic strategy to treat LF.

Vinpocetine and Lactobacillus improve fatty liver in rats: role of adiponectin and gut microbiome

Therapeutics that interfere with the damage/pathogen-associated molecular patterns (DAMPs/PAMPs) have evolved as promising candidates for hepatic inflammation like that occurring in non-alcoholic fatty liver disease (NAFLD). In the current study, we examined the therapeutic impact of the phosphodiesterase-1 inhibitor vinpocetine (Vinpo), alone or when combined with Lactobacillus, on hepatic abnormalities caused by a 13-week high-fat diet (HFD) and diabetes in rats. The results show that Vinpo (10 and 20 mg/kg/day) dose-dependently curbed HFD-induced elevation of liver injury parameters in serum (ALT, AST) and tissue histopathology. These effects were concordant with Vinpo's potential to ameliorate HFD-induced fibrosis (Histological fibrosis score, hydroxyproline, TGF-β1) and oxidative stress (MDA, NOx) alongside restoring the antioxidant-related parameters (GSH, SOD, Nrf-2, HO-1) in the liver. Mechanistically, Vinpo attenuated the hepatocellular release of DAMPs like high mobility group box (HMGB)1 alongside lowering the overactivation of the pattern recognition receptors including, toll-like receptor (TLR)4 and receptor for advanced glycation end-products (RAGE). Consequently, there was less activation of the transcription factor nuclear factor-kappa B that lowered production of the proinflammatory cytokines TNF-α and IL-6 in Vinpo-treated HFD/diabetes rats. Compared to Vinpo treatment alone, Lactobacillus probiotics as adjunctive therapy with Vinpo significantly improved the disease-associated inflammation and oxidative stress injury, as well as the insulin resistance and lipid profile abnormalities via enhancing the restoration of the symbiotic microbiota. In conclusion, combining Vinpo and Lactobacillus probiotics may be a successful approach for limiting NAFLD in humans.

Nonsurgical therapy for lumbar spinal stenosis caused by ligamentum flavum hypertrophy: A review

Lumbar spinal stenosis (LSS) can cause a range of cauda equina symptoms, including lower back and leg pain, numbness, and intermittent claudication. This disease affects approximately 103 million people worldwide, particularly the elderly, and can seriously compromise their health and well-being. Ligamentum flavum hypertrophy (LFH) is one of the main contributing factors to this disease. Surgical treatment is currently recommended for LSS caused by LFH. For patients who do not meet the criteria for surgery, symptom relief can be achieved by using oral nonsteroidal anti-inflammatory drugs (NSAIDs) and epidural steroid injections. Exercise therapy and needle knife can also help to reduce the effects of mechanical stress. However, the effectiveness of these methods varies, and targeting the delay in LF hypertrophy is challenging. Therefore, further research and development of new drugs is necessary to address this issue. Several new drugs, including cyclopamine and N-acetyl-l-cysteine, are currently undergoing testing and may serve as new treatments for LSS caused by LFH.

Design, Synthesis, and Evaluation of Dihydropyrimidine Derivatives as Selective PDE1 Inhibitors for the Treatment of Liver Fibrosis

Liver fibrosis is a common pathological feature of most chronic liver diseases with no effective drugs available. Phosphodiesterase 1 (PDE1), a subfamily of the PDE super enzyme, might work as a potent target for liver fibrosis by regulating the concentration of cAMP and cGMP. However, there are few PDE1 selective inhibitors, and none has been investigated for liver fibrosis treatment yet. Herein, compound AG-205/1186117 with the dihydropyrimidine scaffold was selected as the hit by virtual screening. A hit-to-lead structural modification led to a series of dihydropyrimidine derivatives. Lead 13h exhibited the IC50 of 10 nM against PDE1, high selectivity over other PDEs, as well as good safety properties. Administration of 13h exerted significant anti-liver fibrotic effects in bile duct ligation-induced fibrosis rats, which also prevented TGF-β-induced myofibroblast differentiation in vitro, confirming that PDE1 could work as a potential target for liver fibrosis.

Regulatory pathways and therapeutic potential of PDE4 in liver pathophysiology

Phosphodiesterase 4 (PDE4), crucial in regulating the cyclic adenosine monophosphate (cAMP) signaling pathway, significantly impacts liver pathophysiology. This article highlights the comprehensive effects of PDE4 on liver health and disease, and its potential as a therapeutic agent. PDE4's role in degrading cAMP disrupts intracellular signaling, increasing pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). This contributes to liver inflammation in conditions such as hepatitis and non-alcoholic steatohepatitis (NASH). Additionally, PDE4 is a key factor in liver fibrosis, characterized by excessive extracellular matrix deposition. Inhibiting PDE4 shows promise in reducing liver fibrosis by decreasing the activation of hepatic stellate cells, which is pivotal in fibrogenesis. PDE4 also influences hepatocyte apoptosis a common feature of liver diseases. PDE4 inhibitors protect against hepatocyte apoptosis by raising intracellular cAMP levels, thus activating anti-apoptotic pathways. This suggests potential in targeting PDE4 to prevent hepatocyte loss. Moreover, PDE4 regulates hepatic glucose production and lipid metabolism, essential for liver function. Altering cAMP levels through PDE4 affects enzymes in these metabolic pathways, making PDE4 a target for metabolic disorders like type 2 diabetes and non-alcoholic fatty liver disease (NAFLD). Since PDE4 plays a multifaceted role in liver pathophysiology, influencing PDE4's mechanisms in liver diseases could lead to novel therapeutic strategies. Still, extensive research is required to explore the molecular mechanisms and clinical potential of targeting PDE4 in liver pathologies.

The Protective Effect of Roflumilast Against Acute Hepatotoxicity Caused by Methotrexate in Wistar Rats: In vivo Evaluation

Introduction

Methotrexate (MTX) is one of the most widely used drugs in cancer chemotherapy and treating rheumatoid arthritis. The hepatotoxicity of MTX is one of its major side effects. Roflumilast (ROF) has been recognized to have antioxidant and anti-inflammatory activity in in-vivo and in-vitro models. The present study aimed to explore the potential protective effects of roflumilast against MTX-induced liver toxicity in male Wistar rats.

Methods

High dose of 5 mg/kg for 4 consecutive days subcutaneous (S.C) injection of methotrexate for induction of acute liver injury. A total of 24 Wistar rats, rats were used in four different groups. The NS injections were given S.C to the control group once a day for 4 consecutive days. SC injections of MTX (5 mg/kg) were given to the MTX group daily for four days. At 5 mg/kg once daily for four days, the roflumilast group was given daily oral roflumilast. An injection of MTX and oral roflumilast were given to the MTX + roflumilast group once daily for four consecutive days.

Results

Administration of high dose MTX (5 mg/kg) today 4 produced a significant decrease in hepatic glutathione (GSH) levels and a significant increase in ALT and AST liver enzymes, hepatic malondialdehyde (MDA), tumor suppressor protein (p53), interleukin 6, interleukin 1 levels compared to the control group. Treatment with roflumilast for 4 days significantly attenuated unfavorable changes in these parameters. According to histopathological findings, Roflumilast significantly reduced MTX-induced inflammation and degeneration in the liver. In conclusion, the findings indicate that roflumilast may have a potential therapeutic benefit in treating rats with MTX-induced liver toxicity by mitigating its effects.

Purpose

The aim of this study is to investigate the potential protective effects of roflumilast against MTX-induced liver toxicity in Wistar rats.

A study of roflumilast treatment on functional and structural changes in hippocampus in depressed Adult male Wistar rats

Depression is a common stress disability disorder that affects higher mental functions including emotion, cognition, and behavior. It may be mediated by inflammatory cytokines that interfere with neuroendocrine function, and synaptic plasticity. Therefore, reductions in inflammation might contribute to treatment response. The current study aims to evaluate the role of Protein Kinase (PKA)- cAMP response element-binding protein (CREB)- brain derived neurotropic factor (BDNF) signaling pathway in depression and the effects of roflumilast (PDE4 inhibitor) as potential antidepressant on the activity of the PKA-CREB-BDNF signaling pathway, histology, and pro-inflammatory cytokine production. Forty Adult male Wistar rats were divided into 4 groups: Control group, Positive Control group: similar to the controls but received Roflumilast (3 mg / kg / day) by oral gavage for the last 4 weeks of the experiment, Depressed group which were exposed to chronic stress for 6 weeks, and Roflumilast-treated group which were exposed to chronic stress for 6 weeks and treated by Roflumilast (3 mg / kg / day) by oral gavage for the last 4 weeks of the experiment. The depressed group showed significant increase in immobility time with significant decrease in swimming and struggling times, significant decrease in hippocampal PKA, CERB, BDNF, Dopamine, Cortisone, and Superoxide dismutase while hippocampal Phosphodiesterase-E4, Interleukin-6, and Malondialdhyde levels were significantly elevated. These findings were significantly reversed upon Roflumilast treatment. Therefore, it could be concluded that depression is a neurodegenerative inflammatory disease and oxidative stress plays a key role in depression. Roflumilast treatment attenuated the depression behavior in rats denoting its neuroprotective, and anti-inflammatory effects.

Molecular mechanisms mediate roflumilast protective effect against isoprenaline-induced myocardial injury

BACKGROUND

Myocardial necrosis is one of the most common cardiac and pathological diseases. Unfortunately, using the available medical treatment is not sufficient to rescue the myocardium. So that, we aimed in our model to study the possible cardioprotective effect of roflumilast (ROF) in an experimental model of induced myocardial injury using a toxic dose of isoprenaline (ISO) and detecting the role of vascular endothelial growth factor/endothelial nitric oxide synthase (VEGF/eNOS) and cyclic guanosine monophosphate/cyclic adenosine monophosphate/ sirtuin1 (cGMP/cAMP/SIRT1) signaling cascade.

MATERIALS AND METHODS

Animals were divided into five groups; control, ISO given group (150 mg/kg) i.p. on the 4th and 5th day, 3 ROF co-administered groups in different doses (0.25, 0.5, 1 mg/kg/day) for 5 days.

RESULTS

Our data revealed that ISO could induce cardiac toxicity as manifested by significant increases in troponin I, creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), malondialdehyde (MDA), tumor necrosis factor alpha (TNFα), and cleaved caspase-3 with toxic histopathological changes. Meanwhile, there were significant decreases in reduced glutathione (GSH), total antioxidant capacity (TAC), VEGF, eNOS, cGMP, cAMP and SIRT1. However, co-administration of ROF showed significant improvement and normalization of ISO induced cardiac damage.

CONCLUSION

We concluded that ROF successfully reduced ISO induced myocardial injury and this could be attributed to modulation of PDE4, VEGF/eNOS and cGMP/cAMP/SIRT1 signaling pathways with antioxidant, anti-inflammatory, and anti-apoptotic properties.

Decoding clinical and molecular pathways of liver dysfunction in Psoriatic Arthritis: Impact of cumulative methotrexate doses

BACKGROUND

The occurrence of liver abnormalities in Psoriatic Arthritis (PsA) has gained significant recognition. Identifying key factors at the clinical and molecular level can help to detect high-risk patients for non-alcoholic fatty liver disease in PsA.

OBJECTIVES

to investigate the influence of PsA and cumulative doses of methotrexate on liver function through comprehensive in vivo and in vitro investigations.

METHODS

A cross-sectional study involving 387 subjects was conducted, 200 patients with PsA, 87 NAFLD-non-PsA patients, and 100 healthy donors (HDs), age and sex-matched. Additionally, a retrospective longitudinal study was carried out, including 83 PsA patients since initiation with methotrexate. Detailed clinical, and laboratory parameters along with liver disease risk were analyzed. In vitro, experiments with hepatocyte cell line (HEPG2) were conducted.

RESULTS

PsA patients present increased liver disease risk associated with the presence of cardiometabolic comorbidities, inflammatory markers, onychopathy, and psoriasis. The treatment with PsA serum on hepatocytes encompassed inflammatory, fibrotic, cell stress, and apoptotic processes. At the molecular level, methotrexate impacts liver biology, although the cumulative doses did not affect those alterations, causing any potential damage to liver function at the clinical level. Finally, anti-PDE-4 or anti-JAK decreased the inflammatory profile induced by PsA serum on hepatocytes.

CONCLUSION

1)This study identifies the complex link between liver disease risk, comorbidities, and disease-specific features in PsA patients. 2)Methotrexate dose in PsA patients had no significant effect on liver parameters, confirmed by hepatocyte in vitro studies. 3)Anti-PDE-4 and anti-JAK therapies show promise in reducing PsA serum-induced hepatocyte activation, potentially aiding liver complication management.

WITHDRAWN: Vinpocetine and Lactobacillus improve fatty liver in rats via modulating the oxidative stress, inflammation, adiponectin and gut microbiome

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Identification of Novel Quinolin-2(1H)-ones as Phosphodiesterase 1 Inhibitors for the Treatment of Inflammatory Bowel Disease

Phosphodiesterase 1 (PDE1) is a subfamily of PDE super enzyme families that can hydrolyze cyclic adenosine monophosphate and cyclic guanosine monophosphate simultaneously. Currently, the number of PDE1 inhibitors is relatively few, significantly limiting their application. Herein, a novel series of quinolin-2(1H)-ones were designed rationally, leading to compound 10c with an IC50 of 15 nM against PDE1C, high selectivity across other PDEs, and remarkable safety properties. Furthermore, we used the lead compound 10c as a chemical tool to explore whether PDE1 could work as a novel potential target for the treatment of inflammatory bowel disease (IBD), a disease which is a chronic, relapsing disorder of the gastrointestinal tract inflammation lacking effective treatment. Our results showed that administration of 10c exerted significant anti-IBD effects in the dextran sodium sulfate-induced mice model and alleviated the inflammatory response, indicating that PDE1 could work as a potent target for IBD.

Modulatory effect of rupatadine on mesenchymal stem cell-derived exosomes in hepatic fibrosis in rats: A potential role for miR-200a

AIMS

Mesenchymal stem cell-derived exosomes (MSC-EXOs) have emerged as a promising approach in regenerative medicine for management of different diseases. However, the maintenance of their efficacy after in vivo transplantation is still a major concern. The present investigation aimed to assess the modulatory effect of rupatadine (RUP) on MSC-EXOs in diethylnitrosamine (DEN)-induced liver fibrosis (LF), and to explore the possible underlying mechanism.

MAIN METHODS

LF was induced in rats by i.p. injection of DEN (100 mg/kg) once per week for 6 successive weeks. Rats were then treated with RUP (4 mg/kg/day, p.o.) for 4 weeks with or without a single i.v. administration of MSC-EXOs. At the end of the experiment, animals were euthanized and serum and liver were separated for biochemical, and histological measurements.

KEY FINDINGS

The combined MSC-EXOs/RUP therapy provided an additional improvement towards inhibition of DEN-induced LF compared to MSC-EXOs group alone. These outcomes could be mediated through antioxidant, anti-inflammatory, and anti-fibrotic effects of RUP which created a more favorable environment for MSC-EXOs homing, and action. This in turn would enhance more effectively miR-200a expression which reduced oxidative stress, inflammation, necroptosis pathway, and subsequently fibrosis as revealed by turning off TGF-β1/α-SMA expression, and hedgehog axis.

SIGNIFICANCE

The present findings reveal that RUP enhanced the anti-fibrotic efficacy of MSC-EXOs when used as a combined therapy. This was revealed through attenuation of PAF/RIPK3/MLKL/HMGB1, and TGF-β1/hedgehog signaling pathways with a significant role for miR-200a.

p-CREB and p-DARPP-32 orchestrating the modulatory role of cAMP/PKA signaling pathway enhanced by Roflumilast in rotenone-induced Parkinson's disease in rats

Recently, phosphodiesterases (PDEs) have gained great attention due to their implication in Parkinson's disease (PD) pathogenesis. Noteworthy, the PDE4 enzyme is highly expressed in the striatum and selectively degrades cyclic adenosine monophosphate (cAMP). The cAMP was shown to play a vital role in dopamine (DA) signaling besides maintaining the plasticity of dopaminergic neurons as well as protecting them from inflammation and oxidative stress-mediated death. Thus, PDE4 inhibition could be a promising strategy for treating PD. Accordingly, the present study investigated the neuroprotective efficacy of roflumilast, a PDE4 inhibitor, in abolishing neurodegeneration in the rotenone-induced PD model. Rotenone (1.5 mg/kg, s.c) was delivered via 11 injections on matching days. Roflumilast treatment (0.5 mg/kg, p.o) was given daily after the fifth rotenone injection. Roflumilast significantly reversed rotenone's adverse effects, as it enhanced trophic factors expression and abrogated inflammation as well as oxidative stress. Thus, promoting dopaminergic neuronal plasticity and survival, as well as restoring striatal DA level and function, which resulted in enhanced motor performance. The beneficial effect of roflumilast was mediated through inhibition of striatal PDE4 with consequent activation of cAMP-dependent protein kinase A (PKA) signaling pathways, including the cAMP response element-binding protein (CREB) pathway and dopamine and cAMP-regulated phosphoprotein 32,000 (DARPP-32) pathway that is essential for maintaining dopaminergic function. Therefore, the present work sheds light on the substantial neuroprotective potential of roflumilast in treating PD through the activation of the cAMP/PKA cascade.

A novel mechanistic approach for the anti-fibrotic potential of rupatadine in rat liver via amendment of PAF/NF-ĸB p65/TGF-β1 and hedgehog/HIF-1α/VEGF trajectories

Hepatic fibrosis is one of the major worldwide health concerns which requires tremendous research due to the limited outcomes of the current therapies. The present study was designed to assess, for the first time, the potential therapeutic effect of rupatadine (RUP) in diethylnitrosamine (DEN)-induced liver fibrosis and to explore its possible mechanistic actions. For the induction of hepatic fibrosis, rats were treated with DEN (100 mg/kg, i.p.) once weekly for 6 consecutive weeks, and on the 6th week, RUP (4 mg/kg/day, p.o.) was administered for 4 weeks. Treatment with RUP ameliorated changes in body weights, liver indices, liver function enzymes, and histopathological alterations induced by DEN. Besides, RUP amended oxidative stress, which led to the inhibition of PAF/NF-κB p65-induced inflammation, and, subsequently, prevention of TGF-β1 elevation and HSCs activation as indicated by reduced α-SMA expression and collagen deposition. Moreover, RUP exerted significant anti-fibrotic and anti-angiogenic effects by suppressing Hh and HIF-1α/VEGF signaling pathways. Our results highlight, for the first time, a promising anti-fibrotic potential of RUP in rat liver. The molecular mechanisms underlying this effect involve the attenuation of PAF/NF-κB p65/TGF-β1 and Hh pathways and, subsequently, the pathological angiogenesis (HIF-1α/VEGF).

The role of inflammation in cadmium nephrotoxicity: NF-κB comes into view

Kidney diseases are major health problem and understanding the underlined mechanisms that lead to kidney diseases are critical research points with a marked potential impact on health. Cadmium (Cd) is a heavy metal that occurs naturally and can be found in contaminated food. Kidneys are the most susceptible organ to heavy metal intoxication as it is the main route of waste excretion. The harmful effects of Cd were previously well proved. Cd induces inflammatory responses, oxidative injury, mitochondrial dysfunction and disturbs Ca²⁺ homeostasis. The nuclear factor-kappa B (NF-κB) is a cellular transcription factor that regulates inflammation and controls the expression of many inflammatory cytokines. Therefore, great therapeutic benefits can be attained from NF-κB inhibition. In this review we focused on certain compounds including cytochalasin D, mangiferin, N-acetylcysteine, pyrrolidine dithiocarbamate, roflumilast, rosmarinic acid, sildenafil, sinapic acid, telmisartan and wogonin and certain plants as Astragalus Polysaccharide, Ginkgo Biloba and Thymus serrulatus that potently inhibit NF-κB and effectively counteracted Cd-associated renal intoxication. In conclusion, the proposed NF-κB involvement in Cd-renal intoxication clarified the underlined inflammation associated with Cd-nephropathy and the beneficial effects of NF-κB inhibitors that make them the potential to substantially optimize treatment protocols for Cd-renal intoxication.

BI 1015550 is a PDE4B Inhibitor and a Clinical Drug Candidate for the Oral Treatment of Idiopathic Pulmonary Fibrosis

The anti-inflammatory and immunomodulatory abilities of oral selective phosphodiesterase 4 (PDE4) inhibitors enabled the approval of roflumilast and apremilast for use in chronic obstructive pulmonary disease and psoriasis/psoriatic arthritis, respectively. However, the antifibrotic potential of PDE4 inhibitors has not yet been explored clinically. BI 1015550 is a novel PDE4 inhibitor showing a preferential enzymatic inhibition of PDE4B. In vitro, BI 1015550 inhibits lipopolysaccharide (LPS)-induced tumor necrosis factor-α (TNF-α) and phytohemagglutinin-induced interleukin-2 synthesis in human peripheral blood mononuclear cells, as well as LPS-induced TNF-α synthesis in human and rat whole blood. In vivo, oral BI 1015550 shows potent anti-inflammatory activity in mice by inhibiting LPS-induced TNF-α synthesis ex vivo and in Suncus murinus by inhibiting neutrophil influx into bronchoalveolar lavage fluid stimulated by nebulized LPS. In Suncus murinus, PDE4 inhibitors induce emesis, a well-known gastrointestinal side effect limiting the use of PDE4 inhibitors in humans, and the therapeutic ratio of BI 1015550 appeared to be substantially improved compared with roflumilast. Oral BI 1015550 was also tested in two well-known mouse models of lung fibrosis (induced by either bleomycin or silica) under therapeutic conditions, and appeared to be effective by modulating various model-specific parameters. To better understand the antifibrotic potential of BI 1015550 in vivo, its direct effect on human fibroblasts from patients with idiopathic pulmonary fibrosis (IPF) was investigated in vitro. BI 1015550 inhibited transforming growth factor-β-stimulated myofibroblast transformation and the mRNA expression of various extracellular matrix proteins, as well as basic fibroblast growth factor plus interleukin-1β-induced cell proliferation. Nintedanib overall was unremarkable in these assays, but interestingly, the inhibition of proliferation was synergistic when it was combined with BI 1015550, leading to a roughly 10-fold shift of the concentration–response curve to the left. In summary, the unique preferential inhibition of PDE4B by BI 1015550 and its anticipated improved tolerability in humans, plus its anti-inflammatory and antifibrotic potential, suggest BI 1015550 to be a promising oral clinical candidate for the treatment of IPF and other fibro-proliferative diseases.

Novel Liposomal Rolipram Formulation for Clinical Application to Reduce Emesis

Introduction

The phosphodiesterase 4 (PDE4) inhibitor, rolipram, has beneficial effects on tissue inflammation, injury and fibrosis, including in the liver. Since rolipram elicits significant CNS side-effects in humans (ie, nausea and emesis), our group developed a fusogenic lipid vesicle (FLV) drug delivery system that targets the liver to avoid adverse events. We evaluated whether this novel liposomal rolipram formulation reduces emesis.

Methods

C57Bl/6J male mice were used to compare the effect of three doses of free and FLV-delivered (FLVs-Rol) rolipram in a behavioral correlate model of rolipram-induced emesis. Tissue rolipram and rolipram metabolite levels were measured using LC-MS/MS. The effect of FLVs-Rol on brain and liver PDE4 activities was evaluated.

Results

Low and moderate doses of free rolipram significantly reduced anesthesia duration, while the same doses of FLVs-Rol had no effect. However, the onset and duration of adverse effects (shortening of anesthesia period) elicited by a high dose of rolipram was not ameliorated by FLVs-Rol. Post-mortem analysis of brain and liver tissues demonstrated that FLVs affected the rate of rolipram uptake by liver and brain. Lastly, administration of a moderate dose of FLVs-Rol attenuated endotoxin induced PDE4 activity in the liver with negligible effect on the brain.

Discussion

The findings that the low and moderate doses of FLVs-Rol did not shorten the anesthesia duration time suggest that FLV delivery prevented critical levels of drug from crossing the blood-brain barrier (BBB) to elicit CNS side-effects. However, the inability of high dose FLVs-Rol to prevent CNS side-effects indicates that there was sufficient unencapsulated rolipram to cross the BBB and shorten anesthesia duration. Notably, a moderate dose of FLVs-Rol was able to decrease PDE4 activity in the liver without affecting the brain. Taken together, FLVs-Rol has a strong potential for clinical application for the treatment of liver disease without side effects.

Indole-Based Small Molecules as Potential Therapeutic Agents for the Treatment of Fibrosis

Indole alkaloids are widely distributed in nature and have been particularly studied because of their diverse biological activities, such as anti-inflammatory, anti-tumor, anti-bacterial, and anti-oxidant activities. Many kinds of indole alkaloids have been applied to clinical practice, proving that indole alkaloids are beneficial scaffolds and occupy a crucial position in the development of novel agents. Fibrosis is an end-stage pathological condition of most chronic inflammatory diseases and is characterized by excessive deposition of fibrous connective tissue components, ultimately resulting in organ dysfunction and even failure with significant morbidity and mortality. Indole alkaloids and indole derivatives can alleviate pulmonary, myocardial, renal, liver, and islet fibrosis through the suppression of inflammatory response, oxidative stress, TGF-β/Smad pathway, and other signaling pathways. Natural indole alkaloids, such as isorhynchophylline, evodiamine, conophylline, indirubin, rutaecarpine, yohimbine, and vincristine, are reportedly effective in organ fibrosis treatment. In brief, indole alkaloids with a wide range of pharmacological bioactivities are important candidate drugs for organ fibrosis treatment. The present review discusses the potential of natural indole alkaloids, semi-synthetic indole alkaloids, synthetic indole derivatives, and indole-contained metabolites in organ fibrosis treatment.

PDE1 inhibitors: a review of the recent patent literature (2008-present)

INTRODUCTION

: PDE1 has been demonstrated to be a potential drug target for a variety of diseases, such as Alzheimer's disease and cardiovascular disease. In the past decades, numerous PDE1 inhibitors with structural diversities have been developed and patented by pharmaceutical companies, providing drug candidates for exploring novel disease indications of PDE1.

AREA COVERED

: This review aims to provide an overview of PDE1 inhibitors reported in patents from 2008 to present.

EXPERT OPINION

: Among current PDE1 inhibitors, only a few of them showed high selectivity over other PDEs, which might cause severe side effects in clinic. The development of highly selective PDE1 inhibitors is still the "top priority" in the following research. The selective recognition mechanism of PDE1 with inhibitors should be further elucidated by X-ray crystallography in order to provide evidences for the rational design of selective PDE1 inhibitors. In addition, PDE1 inhibitors should be applied in the different clinical indications beyond CNS diseases.

Phosphodiesterase inhibitor, Vinpocetine, guards against doxorubicin induced cardiotoxicity via modulation of HIF/VEGF and cGMP/cAMP/SIRT signaling pathways

Purpose: Doxorubicin (DOX) is a widely used chemotherapeutic agent complicated with cardiotoxic adverse effects. Up till now, there are no researches discussing the role of vinpocetine (VIN) in DOX cardiotoxicity. Thus, the aim of our work was to study this effect and explore the different involved mechanisms.

Methods:

50 male Wistar albino rats were subjected to DOX toxicity via administration of single i.p. Dose (15 mg/kg) on the 4th day with or without co-administration of VIN (10, 20, 30 mg/kg/day) orally for 5 days.

Results:

Our data revealed that VIN succeeded in protecting the heart against DOX induced damage as manifested by significant decrease of cardiac enzymes, hypoxia inducible factor alpha (HIF-1α), vascular endothelial growth factor-A (VEGF-A), tissue malondialdehyde (MDA), tumor necrosis factor alpha (TNF-α) and caspase3 levels. Furthermore, VIN given group showed marked improvement of the histopathological changes of cardiac injury, total antioxidant capacity (TAC), elevation of reduced glutathione (GSH), cyclic guanosine monophosphate (cGMP), cyclic adenosine monophosphate (cAMP) and sirtuin-1 (SIRT-1).

Conclusion:

We concluded that VIN could ameliorate DOX induced cardiac damage and this effect may be attributed to modulation of HIF/VEGF signaling pathway, up-regulation of cGMP/cAMP/SIRT pathway, inhibition of phosphodiesterase enzyme, besides its anti-apoptotic, anti-inflammatory, and anti-oxidant properties.

Arecoline Enhances Phosphodiesterase 4A Activity to Promote Transforming Growth Factor-β-Induced Buccal Mucosal Fibroblast Activation via cAMP-Epac1 Signaling Pathway

Chewing areca nut (betel quid) is strongly associated with oral submucous fibrosis (OSF), a pre-cancerous lesion. Among the areca alkaloids, arecoline is the main agent responsible for fibroblast proliferation; however, the specific molecular mechanism of arecoline affecting the OSF remains unclear. The present study revealed that arecoline treatment significantly enhanced Transforming growth factor-β (TGF-β)-induced buccal mucosal fibroblast (BMF) activation and fibrotic changes. Arecoline interacts with phosphodiesterase 4A (PDE4A) to exert its effects through modulating PDE4A activity but not PDE4A expression. PDE4A silence reversed the effects of arecoline on TGF-β-induced BMFs activation and fibrotic changes. Moreover, the exchange protein directly activated by cAMP 1 (Epac1)-selective Cyclic adenosine 3′,5′-monophosphate (cAMP) analog (8-Me-cAMP) but not the protein kinase A (PKA)-selective cAMP analog (N6-cAMP) remarkably suppressed α-smooth muscle actin(α-SMA) and Collagen Type I Alpha 1 Chain (Col1A1) protein levels in response to TGF-β1 and arecoline co-treatment, indicating that cAMP-Epac1 but not cAMP-PKA signaling is involved in arecoline functions on TGF-β1-induced BMFs activation. In conclusion, arecoline promotes TGF-β1-induced BMFs activation through enhancing PDE4A activity and the cAMP-Epac1 signaling pathway during OSF. This novel mechanism might provide more powerful strategies for OSF treatment, requiring further in vivo and clinical investigation.

Cytoskeleton Reorganization in EndMT-The Role in Cancer and Fibrotic Diseases

Chronic inflammation promotes endothelial plasticity, leading to the development of several diseases, including fibrosis and cancer in numerous organs. The basis of those processes is a phenomenon called the endothelial–mesenchymal transition (EndMT), which results in the delamination of tightly connected endothelial cells that acquire a mesenchymal phenotype. EndMT-derived cells, known as the myofibroblasts or cancer-associated fibroblasts (CAFs), are characterized by the loss of cell–cell junctions, loss of endothelial markers, and gain in mesenchymal ones. As a result, the endothelium ceases its primary ability to maintain patent and functional capillaries and induce new blood vessels. At the same time, it acquires the migration and invasion potential typical of mesenchymal cells. The observed modulation of cell shape, increasedcell movement, and invasion abilities are connected with cytoskeleton reorganization. This paper focuses on the review of current knowledge about the molecular pathways involved in the modulation of each cytoskeleton element (microfilaments, microtubule, and intermediate filaments) during EndMT and their role as the potential targets for cancer and fibrosis treatment.

Rolipram plays an anti-fibrotic effect in ligamentum flavum fibroblasts by inhibiting the activation of ERK1/2

Background

Fibrosis is an important factor and process of ligamentum flavum hypertrophy. The expression of phosphodiesterase family (PDE) is related to inflammation and fibrosis. This article studied the expression of PDE in hypertrophic ligamentum flavum fibroblasts and investigated whether inhibition of PDE4 activity can play an anti-fibrotic effect.

Methods

Samples of clinical hypertrophic ligamentum flavum were collected and patients with lumbar disc herniations as a control group. The collagenase digestion method is used to separate fibroblasts. qPCR is used to detect the expression of PDE subtypes, type I collagen (Col I), type III collagen (Col III), fibronectin (FN1) and transforming growth factor β1 (TGF-β1). Recombinant TGF-β1 was used to stimulate fibroblasts to make a fibrotic cell model and treated with Rolipram. The morphology of the cells treated with drugs was observed by Sirius Red staining. Scratch the cells to observe their migration and proliferation. WB detects the expression of the above-mentioned multiple fibrotic proteins after drug treatment. Finally, combined with a variety of signaling pathway drugs, the signaling mechanism was studied.

Results

Multiple PDE subtypes were expressed in ligamentum flavum fibroblasts. The expression of PDE4A and 4B was significantly up-regulated in the hypertrophic group. Using Rolipram to inhibit PDE4 activity, the expression of Col I and TGF-β1 in the hypertrophic group was inhibited. Col I recovered to the level of the control group. TGF-β1 was significantly inhibited, which was lower than the control group. Recombinant TGF-β1 stimulated fibroblasts to increase the expression of Col I/III, FN1 and TGF-β1, which was blocked by Rolipram. Rolipram restored the increased expression of p-ERK1/2 stimulated by TGF-β1.

Conclusion

The expressions of PDE4A and 4B in the hypertrophic ligamentum flavum are increased, suggesting that it is related to the hypertrophy of the ligamentum flavum. Rolipram has a good anti-fibrosis effect after inhibiting the activity of PDE4. This is related to blocking the function of TGF-β1, specifically by restoring normal ERK1/2 signal.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04712-9.

Therapeutic targets, novel drugs, and delivery systems for diabetes associated NAFLD and liver fibrosis

Type 2 diabetes mellitus (T2DM) associated non-alcoholic fatty liver disease (NAFLD) is the fourth-leading cause of death. Hyperglycemia induces various complications, including nephropathy, cirrhosis and eventually hepatocellular carcinoma (HCC). There are several etiological factors leading to liver disease development, which involve insulin resistance and oxidative stress. Free fatty acid (FFA) accumulation in the liver exerts oxidative and endoplasmic reticulum (ER) stresses. Hepatocyte injury induces release of inflammatory cytokines from Kupffer cells (KCs), which are responsible for activating hepatic stellate cells (HSCs). In this review, we will discuss various molecular targets for treating chronic liver diseases, including homeostasis of FFA, lipid metabolism, and decrease in hepatocyte apoptosis, role of growth factors, and regulation of epithelial-to-mesenchymal transition (EMT) and HSC activation. This review will also critically assess different strategies to enhance drug delivery to different cell types. Targeting nanocarriers to specific liver cell types have the potential to increase efficacy and suppress off-target effects.

Enhanced anticancer activity by the combination of vinpocetine and sorafenib via PI3K/AKT/GSK-3β signaling axis in hepatocellular carcinoma cells

Vinpocetine is widely used to treat cerebrovascular diseases. However, the effect of vinpocetine to treat hepatocellular carcinoma (HCC) has not been investigated. In this study, we revealed that vinpocetine was associated with antiproliferative activity in HCC cells, but induced cytoprotective autophagy, which restricted its antitumor activity. Autophagy inhibitors improved the antiproliferative activity of vinpocetine in HCC cells. Sorafenib is effective to treat advanced HCC, but the effect of autophagy induced by sorafenib is indistinct. We demonstrated vinpocetine plus sorafenib suppressed the cytoprotective autophagy activated by vinpocetine in HCC cells and significantly induced apoptosis and suppressed cell proliferation in HCC cells. In addition, vinpocetine plus sorafenib activates glycogen synthase kinase 3β (GSK-3β) and subsequently inhibits cytoprotective autophagy induced by vinpocetine in HCC cells. Meanwhile, overexpression of GSK-3β was efficient to increase the apoptosis induced by vinpocetine plus sorafenib in HCC cells. Our study revealed that vinpocetine plus sorafenib could suppress the cytoprotective autophagy induced by vinpocetine and subsequently show synergistically anti-HCC activity via activating GSK-3β and the combination of vinpocetine and sorafenib might reverse sorafenib resistance via the PI3K/protein kinase B/GSK-3β signaling axis. Thus, vinpocetine may be a potential candidate for sorafenib sensitization and HCC treatment, and our results may help to elucidate more effective therapeutic options for HCC patients with sorafenib resistance.

Discovery of Potent Phosphodiesterase-9 Inhibitors for the Treatment of Hepatic Fibrosis

Hepatic fibrosis commonly exists in chronic liver disease and would eventually develop to cirrhosis and liver cancer with high fatality. Phosphodiesterase-9 (PDE9) has attracted profound attention as a drug target because of its highest binding affinity among phosphodiesterases (PDEs) with cyclic guanosine monophosphate. However, no published study has reported PDE9 inhibitors as potential agents against hepatic fibrosis yet. Herein, structural modification from a starting hit LL01 led to lead 4a, which exhibited an IC₅₀ value of 7.3 nM against PDE9, excellent selectivity against other PDE subfamilies, and remarkable microsomal stability. The cocrystal structure of PDE9 with 4a revealed an important residue, Phe441, capable of improving the selectivity of PDE9 inhibitors. Administration of 4a exerted a significant antifibrotic effect in bile duct-ligation-induced rats with hepatic fibrosis and transforming growth factor-β-induced fibrogenesis. This therapeutic effect was indeed achieved by selectively inhibiting PDE9 rather than other PDE isoforms, identifying PDE9 inhibitors as potential agents against hepatic fibrosis.

Evodiamine Enhanced the Anti-Inflammation Effect of Clindamycin in the BEAS-2B Cells Infected with H5N1 and Pneumoniae D39 Through CREB-C/EBPβ Signaling Pathway

Pneumonia is a pulmonary disease among children. Evodiamine, a traditional Chinese medicine, is known for anti-inflammatory effect. This study aimed to investigate the impact of evodiamine on severe pneumonia-like cells and the underlying mechanism involved. H5N1 and pneumoniae D39 was used to induce severe pneumonia-like conditions in BEAS-2B cells. The cell viability in BEAS-2B cells after treatments with 0, 20, 40, 60, 80, and 100 μM evodiamine was examined using MTT assays. The protein concentrations of inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β, and Toll-like receptors (TLRs) were measured by enzyme-linked immunosorbent assay methods and the protein and mRNA changes in C/EBPβ/CREB were measured using Real Time-quantitative polymerase chain reaction and Western blot methods. Our results revealed that Evodiamine significantly decreased TNF-α, IL-6, and IL-1β in BEAS-2B cells. Moreover, evodiamine markedly reduced TLR2,3,4 protein expression and the phosphorylated protein of C/EBPβ and CREB. Besides, evodiamine combined with clindamycin exerted more significant effects than clindamycin alone. Taken together, our results demonstrated that evodiamine enhanced the anti-inflammation effect of clindamycin in the BEAS-2B cells infected with H5N1 and pneumoniae D39 through CREB-C/EBPβ signaling pathway.

Roflumilast Ameliorates Isoflurane-Induced Inflammation in Astrocytes via the CREB/BDNF Signaling Pathway

Background and purpose: Astrocyte-mediated neuroinflammation plays an important role in anesthetic isoflurane-induced cognitive impairment. Roflumilast, a selective inhibitor of phosphodiesterase-4 (PDE-4) used for the treatment of chronic obstructive pulmonary disease (COPD), has displayed a wide range of anti-inflammatory capacity in different types of cells and tissues. In the current study, we aimed to investigate whether roflumilast possesses a protective effect against isoflurane-induced insults in mouse primary astrocytes. Methods: Primary astrocytes were isolated from the cerebral cortices of immature rats. The production of NO was determined using DAF-FM DA staining assay. QRT-PCR and western blot were used to evaluate the expression levels of iNOS, COX-2, and BDNF in the astrocytes treated with different therapies. The gene expressions and concentrations of IL-6 and MCP-1 released by the astrocytes were detected using qRT-PCR and ELISA, respectively. The expression levels of phosphorylated CREB and PGE₂ were determined using western blot and ELISA, respectively. H89 was introduced to evaluate the function of CREB. Recombinant human BDNF and ANA-12 were used to verify the role of BDNF. Results: The upregulated iNOS, excessive production of NO, IL-6, and MCP-1, and activated COX-2/PGE₂ signaling pathways in the astrocytes induced by isoflurane were significantly reversed by the introduction of roflumilast, in a dose-dependent manner. Subsequently, we found that BDNF could be upregulated by roflumilast, which was verified to be related to the activation of CREB and blocked by H89 (a CREB inhibitor). In addition, the COX-2/PGE₂ signaling pathway activated by isoflurane can be inactivated by recombinant human BDNF. Finally, the regulatory effect of roflumilast against the isoflurane-activated COX-2/PGE₂ signaling pathway was significantly blocked by ANA-12, which is a BDNF inhibitor. Conclusion: Roflumilast might ameliorate isoflurane-induced inflammation in astrocytes via the CREB/BDNF signaling pathway.

Inhibition of PDE1-B by Vinpocetine Regulates Microglial Exosomes and Polarization Through Enhancing Autophagic Flux for Neuroprotection Against Ischemic Stroke

Exosomes contribute to cell–cell communications. Emerging evidence has shown that microglial exosomes may play crucial role in regulation of neuronal functions under ischemic conditions. However, the underlying mechanisms of microglia-derived exosome biosynthesis are largely unknown. Herein, we reported that the microglial PDE1-B expression was progressively elevated in the peri-infarct region after focal middle cerebral artery occlusion. By an oxygen-glucose-deprivation (OGD) ischemic model in cells, we found that inhibition of PDE1-B by vinpocetine in the microglial cells promoted M2 and inhibited M1 phenotype. In addition, knockdown or inhibition of PDE1-B significantly enhanced the autophagic flux in BV2 cells, and vinpocetine-mediated suppression of M1 phenotype was dependent on autophagy in ischemic conditions. Co-culture of BV2 cells and neurons revealed that vinpocetine-treated BV2 cells alleviated OGD-induced neuronal damage, and treatment of BV2 cells with 3-MA abolished the observed effects of vinpocetine. We further demonstrated that ischemia and vinpocetine treatment significantly altered microglial exosome biogenesis and release, which could be taken up by recipient neurons and regulated neuronal damage. Finally, we showed that the isolated exosome per se from conditioned BV2 cells is sufficient to regulate cortical neuronal survival in vivo. Taken together, these results revealed a novel microglia-neuron interaction mediated by microglia-derived exosomes under ischemic conditions. Our findings further suggest that PDE1-B regulates autophagic flux and exosome biogenesis in microglia which plays a crucial role in neuronal survival under cerebral ischemic conditions.

Vinpocetine attenuates thioacetamide-induced liver fibrosis in rats

Liver fibrosis is associated with increased mortality and morbidity. However, there is not effective treatment so far. Vinpocetine (Vinpo) is a synthetic derivative of vinca alkaloid vincamine. Limited previous reports have shown some beneficial effects of Vinpo in different organ fibrosis, but the ability of Vinpo to inhibit liver fibrosis induced by thioacetamide (TAA) has not been reported, that is why we investigate the potential ability of this vinca alkaloid derivative to attenuate liver fibrosis. Hepatic fibrosis was induced in male Sprague Dawley rats by TAA (200 mg/kg; ip; 3 times/week) for 6 weeks. Daily treatments with Vinpo (10-20 mg/kg/day; orally) ameliorated TAA-induced hepatic oxidative stress and histopathological damage as indicated by a decrease in liver injury markers, LDH, hepatic MDA, and NOx levels, as well as increase anti-oxidative parameters. Besides, the anti-fibrotic efficacy of Vinpo was confirmed by decreasing hydroxyproline, and α-SMA. Also, the anti-inflammatory effect of Vinpo was explored by decreasing IL-6 and TNF-α levels. Our novel findings were that Vinpo decreased VEGF/Ki-67 expression in the liver confirming its effect on angiogenesis and proliferation. These findings reveal the anti-fibrotic effect of Vinpo against TAA-induced liver fibrosis in rats, and suggest the modulation of oxidative stress, inflammation, angiogenesis and proliferation as mechanistic cassette underlines this effect.

Integrative microRNA and mRNA expression profiling in acute aristolochic acid nephropathy in mice

In acute aristolochic acid nephropathy (AAN), aristolochic acid (AA) induces renal injury and tubulointerstitial fibrosis. However, the roles of microRNAs (miRNAs/miRs) and mRNAs involved in AAN are not clearly understood. The aim of the present study was to examine AA‑induced genome‑wide differentially expressed (DE) miRNAs and DE mRNAs using deep sequencing in mouse kidneys, and to analyze their regulatory networks. In the present self‑controlled study, mice were treated with 5 mg/kg/day AA for 5 days, following unilateral nephrectomy. AA‑induced renal injury and tubulointerstitial fibrosis were detected using hematoxylin and eosin staining and Masson's trichrome staining in the mouse kidneys. A total of 82 DE miRNAs and 4,605 DE mRNAs were identified between the AA‑treated group and the self‑control group. Of these DE miRNAs and mRNAs, some were validated using reverse transcription‑quantitative PCR. Expression levels of the profibrotic miR‑21, miR‑433 and miR‑132 families were significantly increased, whereas expression levels of the anti‑fibrotic miR‑122‑5p and let‑7a‑1‑3p were significantly decreased. Functions and signaling pathways associated with the DE miRNAs and mRNAs were analyzed using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG). A total of 767 DE pairs (in opposing directions) of miRNAs and their mRNA targets were identified. Among these, regulatory networks of miRNAs and mRNAs were analyzed using KEGG to identify enriched signaling pathways and extracellular matrix‑associated pathways. In conclusion, the present study identified genome‑wide DE miRNAs and mRNAs in the kidneys of AA‑treated mice, as well as their regulatory pairs and signaling networks. The present results may improve the understanding of the role of DE miRNAs and their mRNA targets in the pathophysiology of acute AAN.

Anti-apoptotic effect of vinpocetine on cisplatin-induced hepatotoxicity in mice: The role of Annexin-V, Caspase-3, and Bax

Hepatic damage is one of the most common complications related to cisplatin (Cis) use. Recently, liver protection lines are being discovered to avoid hepatic cell death as a result of oxidative, inflammatory, and apoptotic disturbance. Limited data reported the hepatoprotective effect of vinpocetine (Vin) in acute liver injury models. This study was designed to determine the potential protective effect of Vin (10-30 mg/kg, orally) against Cis-induced liver injury (10 mg/kg, IP) in mice. Vin administration for 1 week before Cis injection until the end of the experiment. On the 6th day after Cis injection, mice were anesthetized, blood and tissue samples were collected. Hepatic function, histological changes, oxidative stress, inflammation, and apoptotic markers were investigated. Vin administration ameliorated liver injury as indicated by decreased liver injury parameters; serum aminotransferases, ALK-P, GGT, and bilirubin, restored the anti-oxidant status by decrease MDA and NO_x , and increased GSH and SOD, inhibited inflammation (IL-6, TNF-α, NFκB-p65, and iNOS) and apoptosis (Annexin-V, Bax, and Caspase-3) parameters. Vin confers dose-dependent protection against Cis-induced liver injury. The hepatoprotective effect of Vin involved anti-oxidative, anti-inflammatory, and anti-apoptotic activities.

Phosphodiesterase Inhibitors for Alzheimer's Disease: A Systematic Review of Clinical Trials and Epidemiology with a Mechanistic Rationale

BACKGROUND

Preclinical studies, clinical trials, and reviews suggest increasing 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP) with phosphodiesterase inhibitors is disease-modifying in Alzheimer's disease (AD). cAMP/protein kinase A (PKA) and cGMP/protein kinase G (PKG) signaling are disrupted in AD. cAMP/PKA and cGMP/PKG activate cAMP response element binding protein (CREB). CREB binds mitochondrial and nuclear DNA, inducing synaptogenesis, memory, and neuronal survival gene (e.g., brain-derived neurotrophic factor) and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α). cAMP/PKA and cGMP/PKG activate Sirtuin-1, which activates PGC1α. PGC1α induces mitochondrial biogenesis and antioxidant genes (e.g.,Nrf2) and represses BACE1. cAMP and cGMP inhibit BACE1-inducing NFκB and tau-phosphorylating GSK3β.

OBJECTIVE AND METHODS

We review efficacy-testing clinical trials, epidemiology, and meta-analyses to critically investigate whether phosphodiesteraseinhibitors prevent or treat AD.

RESULTS

Caffeine and cilostazol may lower AD risk. Denbufylline and sildenafil clinical trials are promising but preliminary and inconclusive. PF-04447943 and BI 409,306 are ineffective. Vinpocetine, cilostazol, and nicergoline trials are mixed. Deprenyl/selegiline trials show only short-term benefits. Broad-spectrum phosphodiesterase inhibitor propentofylline has been shown in five phase III trials to improve cognition, dementia severity, activities of daily living, and global assessment in mild-to-moderate AD patients on multiple scales, including the ADAS-Cogand the CIBIC-Plus in an 18-month phase III clinical trial. However, two books claimed based on a MedScape article an 18-month phase III trial failed, so propentofylline was discontinued. Now, propentofylline is used to treat canine cognitive dysfunction, which, like AD, involves age-associated wild-type Aβ deposition.

CONCLUSION

Phosphodiesterase inhibitors may prevent and treat AD.

Crocin attenuates cisplatin-induced hepatotoxicity via TLR4/NF-κBp50 signaling and BAMBI modulation of TGF-β activity: Involvement of miRNA-9 and miRNA-29

TLR4-induced mitigation of the BMP down-regulation and activin membrane bound inhibitor (BAMBI) and the consequent enhancement of the transforming growth factor-beta (TGF-β) profibrogenic signaling has not yet been studied in cisplatin (CIS)-induced hepatotoxicity. miRNA-9 and29 have been previously reported to modulate TLR4 signaling via either tempering the expression of nuclear factor kappa-B p50 (NF-κB p50) or downregulation of extracellular matrix genes respectively. Hence we aimed to investigate the involvement of TLR4-induced modulation of TGF-β receptor 1 (TGF-βR1) signaling as well as the implication of miRNA-9 and 29 in CIS-induced hepatotoxicity. Moreover, we examined the ability of the phytochemical; crocin (CROC); to interact with either TLR4 or TGF-βR1 through a molecular docking study and subsequently explore its capability to attenuate CIS-induced hepatotoxicity. CROC pretreatment ameliorated the CIS-induced enhancement of TLR4 and TGF-β signaling and enhanced the expression of BAMBI, miRNA-9 and 29. Accordingly, it may be assumed that the protective effect of CROC against CIS-induce hepatotoxicity is mediated via the crosstalk of TLR4/NF-κBp50 signaling and BAMBI modulation of TGF-β1 activity in addition to the up-regulation of miRNA-9 and 29. These findings came in alignment with our molecular docking results; emphasizing the molecular antagonistic activity of CROC in both TLR4 and TGF-βR1.

Role of vinpocetine in ischemic stroke and poststroke outcomes: A critical review

Vinpocetine (VPN) is a synthetic ethyl-ester derivative of the alkaloid apovincamine from Vinca minor leaves. VPN is a selective inhibitor of phosphodiesterase type 1 (PDE1) that has potential neurological effects through inhibition of voltage-gated sodium channel and reduction of neuronal calcium influx. VPN has noteworthy antioxidant, anti-inflammatory, and anti-apoptotic effects with inhibitory effect on glial and astrocyte cells during and following ischemic stroke (IS). VPN is effective as adjuvant therapy in the management of epilepsy; it reduces seizure frequency by 50% in a dose of 2 mg/kg/day. VPN improves psychomotor performances through modulation of brain monoamine pathway mainly on dopamine and serotonin, which play an integral role in attenuation of depressive symptoms. VPN recover cognitive functions and spatial memory through inhibition of hippocampal and cortical PDE1 with augmentation of cyclic adenosin monophosphate and cyclic guanosin monophosphate ratio, enhancement of cholinergic neurotransmission, and inhibition of neuronal inflammatory mediators. Therefore, VPN is an effective agent in the management of IS and plays an integral role in the prevention and attenuation of poststroke epilepsy, depression, and cognitive deficit through direct cAMP/cGMP-dependent pathway or indirectly through anti-inflammatory and antioxidant effects.