Discovery of 7-alkoxybenzofurans as PDE4 inhibitors with hepatoprotective activity in D-GalN/LPS-induced hepatic sepsis.

Sepsis can quickly result in fatality for critically ill individuals, while liver damage can expedite the progression of sepsis, necessitating the exploration of new strategies for treating hepatic sepsis. PDE4 has been identified as a potential target for the treatment of liver damage. The scaffold hopping of lead compounds FCPR16 and Z19153 led to the discovery of a novel 7-methoxybenzofuran PDE4 inhibitor 4e, demonstrating better PDE4B (IC50 = 10.0 nM) and PDE4D (IC50 = 15.2 nM) inhibitor activity as a potential anti-hepatic sepsis drug in this study. Compared with FCPR16 and Z19153, 4e displayed improved oral bioavailability (F = 66 %) and longer half-life (t1/2 = 2.0 h) in SD rats, which means it can be more easily administered and has a longer-lasting effect. In the D-GalN/LPS-induced liver injury model, 4e exhibited excellent hepatoprotective activity against hepatic sepsis by decreasing ALT and AST levels and inflammatory infiltrating areas.

A Pair of Epimers of Lignan Alleviate Neuroinflammatory Effects by Modulating iNOS/COX-2 and MAPK/NF-κB Signaling Pathways.

Neuroinflammation is a causative factor in neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis. Previous studies have shown that Artemisia mongolica has anti-inflammatory properties. Aschantin (AM3) has been shown to have anti-inflammatory effects. However, the mechanism of AM3 and its epimer epi-aschantin (AM2) remains controversial. Therefore, the present study explored the mechanism of neuroinflammation by AM2 and AM3 and attempted to reveal the relationship between the structure of AM2 and AM3 and anti-neuroinflammatory activity. We isolated for the first time 12 lignans from A. mongolica that inhibited NO content at 10 µM in LPS-stimulated BV2 cells. Among them, epi-aschantin (AM2) and Aschantin (AM3) showed significant inhibition in NO screening. With further studies, we found that both AM2 and AM3 effectively inhibited the overproduction of NO, PGE2, IL-6, TNF-α and MCP-1, as well as the overexpression of COX-2 and iNOS. Mechanistic studies have shown AM2 and AM3 significantly inhibited the phosphorylation of ERK, JNK and P-38 in the MAPK signaling pathway and p-IκBα,p-p65 and blocked p65 entry into the nucleus. The results suggested that the pair of epimers (AM2 and AM3) can be used as potential therapeutic agents in the treatment of various brain disorders and that structural differences do not differ in anti-neuroinflammatory effects.

Four undescribed sesquiterpenes from Artemisia mongolica and their anti-inflammatory activity.

Four undescribed sesquiterpene compounds (1-4) and six known compounds (5-10) were isolated from A. mongolica. Furthermore, compound 5 was a new natural product previously synthesized. The LPS-stimulated BV2 cells were used as a model to evaluate the anti-inflammatory activity of the isolated compounds, among them, compounds 2, 3 and 4 showed significant inhibition of NO levels with IC50 values of 27.48, 27.39 and 24.96 µM, respectively.

Inhibition of PDE4 Attenuates TNF-α-Triggered Cell Death Through Suppressing NF-κB and JNK Activation in HT-22 Neuronal Cells.

Tumor necrosis factor-α (TNF-α) is a critical pro-inflammatory cytokine regulating neuroinflammation. At high concentrations, it is toxic to neurons, and such damage is positively correlated with acute and chronic neurological diseases. Our previous studies showed that inhibition of phosphodiesterase 4 (PDE4) attenuated the production of TNF-α induced by lipopolysaccharides in microglial cells. However, whether PDE4 inhibition can block the neurotoxic effects of TNF-α in neuronal cells is unknown. In this study, we investigated the protective effects of FCPR16, a novel PDE4 inhibitor, against TNF-α-induced cellular apoptosis in HT-22 hippocampal neuronal cells. We demonstrated that FCPR16 dose-dependently increased the viability of HT-22 cells exposed to TNF-α insult. Propidium iodide/calcein staining and flow cytometry analysis showed that FCPR16 decreased cell apoptosis triggered by TNF-α. Western blot analysis showed that FCPR16 decreased the level of cleaved caspase 3 and caspase 8, but had no effect on caspase 9. Mechanistically, FCPR16 blocked the TNF-α-induced phosphorylation of c-Jun N-terminal kinase (JNK) in HT-22 cells, and inhibition of JNK showed a similar protective effect as FCPR16. Furthermore, FCPR16 decreased the translocation of nuclear factor-κB (NF-κB) p65 from the cytosol into the nucleus. In addition, FCPR16 decreased the expression of inducible nitric oxide synthase and the production of reactive oxygen species in HT-22 cells exposed to TNF-α. Moreover, knockdown of PDE4B by specific small interfering RNA reduced the apoptosis of HT-22 cells treated with TNF-α. Taken together, our findings suggest that FCPR16 promotes the survival of neuronal cells exposed to TNF-α by suppressing the activation of JNK and NF-κB.

Inhibition of PDE4 by FCPR16 induces AMPK-dependent autophagy and confers neuroprotection in SH-SY5Y cells and neurons exposed to MPP+-induced oxidative insult.

The etiology of Parkinson's disease (PD) is generally not well understood, but it is believed to involve excessive oxidative insult. Hence, identifying therapeutic targets and compounds that exhibit protective effects against oxidative damage is a reasonable strategy to slow down the progression of PD. FCPR16 is a novel phosphodiesterase 4 inhibitor with little emetic potential. Our previous studies showed that FCPR16 was able to block 1-Methyl-4-phenylpyridine (MPP+)-induced oxidative damage in SH-SY5Y cells and neurons. However, the detailed mechanism of this is unknown. Here, we found that FCPR16 triggered autophagy in SH-SY5Y cells, as evidenced by an increased level of microtubule-associated protein 1 light chain 3 II (LC3-II) and decreased p62. Inhibition of autophagy by 3-MA or chloroquine decreased the effect of FCPR16 on the accumulation of autophagic vacuoles and the fluorescence signal of lysosomes. In SH-SY5Y cells treated with MPP+, we found that FCPR16 increased the level of LC3-II, and 3-MA attenuated the protective effect of FCPR16 against MPP+-induced toxicity. Treatment of SH-SY5Y cells with FCPR16 prevented MPP+-induced production of reactive oxygen species (ROS) and the decline of mitochondrial membrane potential (Δψm). Importantly, we also found that FCPR16 phosphorylated and thus activated AMP-activated protein kinase (AMPK) in SH-SY5Y cells treated with MPP+. In contrast, blockade of the AMPK pathway with compound C blocked the role of FCPR16 in autophagy enhancement. Similarly, the roles of FCPR16 in the production of ROS, decline of Δψm, and neuroprotection were blocked by compound C as well. Similar results were consistently obtained in primary cultured neurons. Taken together, these results suggest that FCPR16 is effective in protecting SH-SY5Y cells and neurons against oxidative stress via AMPK-dependent autophagy. Our findings indicate the potential application of FCPR16 in PD treatment.

FCPR03, a novel phosphodiesterase 4 inhibitor, alleviates cerebral ischemia/reperfusion injury through activation of the AKT/GSK3ß/ ß-catenin signaling pathway.

Inhibition of phosphodiesterase 4 (PDE4) is a promising strategy for the treatment of ischemic stroke. However, the side effects of nausea and vomiting from the current PDE4 inhibitors have limited their clinical applications. FCPR03 is a novel PDE4 inhibitor with little emetic potential. This study aimed to investigate the effects of FCPR03 on neuronal injury after cerebral ischemia/reperfusion and the underlying signaling pathway. The effects of FCPR03 on cellular apoptosis, intracellular accumulation of reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) were evaluated in HT-22 neuronal cells and cortical neurons exposed to oxygen-glucose deprivation (OGD). The impact of FCPR03 on brain injury, neurological scores and behavioral performance was investigated in rats subjected to middle cerebral artery occlusion (MCAO). The protein kinase B (AKT) inhibitor MK-2206 and ß-catenin siRNA were used to investigate the underlying pathways. FCPR03 dose-dependently protected against OGD-induced cellular apoptosis in both HT-22 cells and cortical neurons. The levels of MMP and ROS were also restored by FCPR03. FCPR03 increased the levels of phosphorylated AKT, glycogen synthase kinase-3ß (GSK3ß), and ß-catenin. Interestingly, the role of FCPR03 was reversed by MK-2206 and ß-catenin siRNA. Consistently, FCPR03 reduced the infarct volume and improved neurobehavioral outcomes in rats following MCAO. Moreover, FCPR03 increased the levels of phosphorylated AKT, GSK3ß and ß-catenin within the ischemic penumbra of rats following cerebral ischemia-reperfusion. Taken together, FCPR03 has therapeutic potential in cerebral ischemia-reperfusion. The neuroprotective effects of FCPR03 are mediated through activation of the AKT/GSK3ß/ß-catenin pathway.