Panaxynol protects cortical neurons from ischemia-like injury by up-regulation of HIF-1α expression and inhibition of apoptotic cascade

Molecular mechanism of Chang Shen Hua volatile oil modulating brain cAMP-PKA-CREB pathway to improve depression-like behavior in rats

BACKGROUND

Depression is a common and complex mental illness that manifests as persistent episodes of sadness, loss of interest, and decreased energy, which might lead to self-harm and suicide in severe cases. Reportedly, depression affects 3.8 % of the world's population and has been listed as one of the major global public health concerns. In recent years, aromatherapy has been widely used as an alternative and complementary therapy in the prevention and treatment of depression; people can relieve anxiety and depression by sniffing plant aromatic essential oils. Acorus tatarinowii and Panax ginseng essential oils in Chang Shen Hua volatile oil (CSHVO) are derived from Acorus tatarinowii and Panax ginseng, respectively, the main medicines in the famous Chinese medicine prescription Kai Xin San (KXS), Then, these oils are combined with the essential oil of Albizia julibrissin flower to form a new Chinese medicine inhalation preparation, CSHVO. KXS has been widely used in the treatment of depression; however, whether CSHVO can ameliorate depression-like behavior, its pharmacological effects, and the underlying mechanisms of action are yet to be elucidated.

STUDY DESIGN AND METHODS

A rat model of chronic and unpredictable mild stimulation (CUMS) combined with orphan rearing was treated with CSHVO for 4 weeks. Using behavioral tests (sucrose preference, force swimming, tail suspension, and open field), the depression-like degree was evaluated. Concurrently, brain homogenate and serum biochemistry were analyzed to assess the changes in the neurotransmitters and inflammatory and neurotrophic factors. Furthermore, tissue samples were collected for histological and protein analyses. In addition, network pharmacology and molecular docking analyses of the major active compounds, potential therapeutic targets, and intervention pathways predicted a role of CSHVO in depression relief. Subsequently, these predictions were confirmed by in vitro experiments using a corticosterone (CORT)-induced PC12 cell damage model.

RESULTS

CSHVO inhalation can effectively improve the weight and depression-like behavior of depressed rats and regulate the expression of inflammatory factors and neurotransmitters. Hematoxylin-eosin, Nissl, and immunofluorescence staining indicated that compared to the model group, the pathological damage to the brain tissues of rats in the CSHVO groups was improved. The network pharmacological analysis revealed that 144 CSHVO active compounds mediate 71 targets relevant to depression treatment, most of which are rich in the cAMP signaling and inflammatory cytokine pathways. Protein-protein interaction analysis showed that TNF, IL6, and AKT are the core anti-depressive targets of CSHVO. Molecular docking analysis showed an adequate binding between the active ingredients and the key targets. In vitro experiments showed that compared to the model group, the survival rate of PC12 cells induced by CSHVO intervention was increased, the apoptosis rate was decreased, and the expression of inflammatory cytokines in the cell supernatant was improved. Western blot analysis and immunofluorescence staining confirmed that CSHVO regulates PC12 cells in the CORT model through the cAMP-PKA-CREB signaling pathway, and pretreatment with PKA blocker H89 eliminates the protective effect of CSHVO on CORT-induced PC12 cells.

CONCLUSIONS

CSHVO improves CORT-induced injury in the PC12 cell model and CUMS combined with orphan rearing-induced depression model in rats. The antidepressant mechanism of CSHVO is associated with the modulation of the cAMP-PKA-CREB signaling pathway.

Panaxynol ameliorates cardiac ischemia/reperfusion injury by suppressing NLRP3-induced pyroptosis and apoptosis via HMGB1/TLR4/NF-κB axis

BACKGROUND AND PURPOSE

Panaxynol (PNN) is a common natural minor component in Umbelliferae plants. Many clinical studies have shown that PNN exhibits nutritional value and anti-inflammatory and other pharmacological activities. However, whether PNN can mediate cardiac ischemia/reperfusion injury (IRI) remains unclear. Here, we aimed to determine the potential effects of PNN on myocardial IRI.

METHODS

Myocardial IRI was stimulated in a mouse IRI model, and neonatal rat ventricle myocytes (NRVMs) were exposed to hypoxia/reoxygenation to construct in an vitro model. Myocardial infarction size, myocardial tissue injury, myocardial apoptotic index, hemodynamic monitoring, pyroptosis-related proteins, cardiac enzyme activities and inflammatory responses were examined to assess myocardial injury.

RESULTS

It was found that PNN administration markedly reduced myocardial infarct size and apoptosis, suppressed myocardial damage and cell pyroptosis, attenuated pro-inflammatory cytokines and neutrophil infiltration via NLRP3 inhibitor. More importantly, PNN treatment remarkably decreased the expression of TLR4/NF-κB pathway-associated proteins and NLRP3-related pyroptosis proteins by HMGB1 inhibitor. PNN also enhanced cell viability, reduced cardiac enzyme activities, suppressed apoptosis and attenuated inflammation in the isolated NRVMs. Furthermore, vitro studies indicated that MCC950 (a NLRP3 inhibitor) increased the anti-inflammatory and anti-apoptotic effects of PNN on NRVMs via HMGB1/TLR4 pathway.

CONCLUSION

To sum up, our results demonstrate that PNN exhibits a cardioprotective effect by modulating heart IRI-induced apoptosis and pyroptosis via HMGB1/TLR4/NF-κB pathway, thereby inhibiting NLRP3 inflammasome stimulation.

Panaxynol induces fibroblast-like synovial cell apoptosis, inhibits proliferation and invasion through TLR4/NF-κB pathway to alleviate rheumatoid arthritis

BACKGROUND AND PURPOSE

Panaxynol (PAL, PubChem CID: 5281149) is a common natural minor component in Umbelliferae plants, such as Radix Saposhnikoviae Divaricatae. Modern pharmacology studies show that PAL has nutritional value and anti-inflammatory and other pharmaceutical activities. Therefore, the scientific hypothesis of PAL in the treatment of rheumatoid arthritis was put forward, and the hypothesis was further verified by Fibroblast-like synovial cells (RA-FLS) and Collagen Induced Arthritis (CIA) rats models.

EXPERIMENTAL METHOD

CIA method was used to establish a rat arthritis model. After extracting RA-FLS, flow cytometry and immunofluorescence were used to explore the effect of PAL on the apoptosis and proliferation of RA-FLS. Wound healing and transwell experiment explored the effect of PAL on the migration and invasion of RA-FLS. Western blot analysis explored the inner mechanism of the effect of PAL on RA-FLS. At the same time, it also explored the role of PAL in CIA rats, including pathological section detection and western blot analysis.

MAIN RESULTS

PAL can promote the apoptosis and inhibit the proliferation, migration and invasion of RA-FLS. PAL can also reduce joint swelling in CIA rats, reduce pannus formation and inflammatory infiltration in the joints. Western blot analysis showed that PAL mainly played a role through the TLR4/NF-κB signaling pathway.

CONCLUSION

The results of in vivo and in vitro experiments show that PAL can effectively alleviate the condition of RA, and may be a potential drug for the treatment of RA.

Panaxynol attenuates CUMS-induced anxiety and depressive-like behaviors via regulating neurotransmitters, synapses and the HPA axis in mice

Panaxynol (PAL, also called falcarinol) is widely found in plants of the Umbelliferae family, among which carrots are rich in PAL, so it is proved to be edible. PAL has neuroprotective effects and other pharmacological activities. This study aimed to explore the effects and mechanisms of action of PAL on chronic unpredictable mild stress (CUMS)-induced anxiety and depression in mice. The effects of PAL on behavioral activities in mice were first assessed by a CUMS-induced depression model. The secretion levels of monoamine neurotransmitters and hypothalamic-pituitary-adrenal (HPA) axis-related hormones were measured by ELISA. Western blotting was used to analyze the expression of glucocorticoid receptor (GR), glutamate receptor 1 (GluR1) and synapse-associated protein in the hippocampus. The behavioral experiment results showed that PAL can improve exploratory behavior and activities in mice. Meanwhile, PAL can significantly activate the release of 5-HT/5-HIAA and DA/HVA in the hippocampus. It inhibits the expression of adrenocorticotropic hormone (ACTH), corticosterone (CORT) and corticotrophin-releasing hormone (CRH) in serum and the hypothalamus. The contents of GR, glutamate receptor 1 (GluR1), postsynaptic density-95 (PSD95) and synapsin I protein in the hippocampus significantly increased. Studies have found that PAL can inhibit the hyperfunction of the HPA axis, which may be achieved by regulating HPA axis hormones and GR. Meanwhile, PAL promotes the release of 5-HT and DA in the hippocampus and improves synaptic plasticity in the hippocampus, allowing neurotransmitters to function more effectively. Therefore, PAL may improve anxiety and depression-like effects in mice through the abovementioned effects.

Panaxynol, a bioactive component of American ginseng, targets macrophages and suppresses colitis in mice

Ulcerative colitis has a significant impact on the quality of life for the patients, and can substantially increase the risk of colon cancer in patients suffering long-term. Conventional treatments provide only modest relief paired with a high risk of side effects, while complementary and alternative medicines can offer safe and effective options. Over the past decade, we have shown that both American ginseng and its hexane fraction (HAG) have anti-oxidant and anti-inflammatory properties that can suppress mouse colitis and prevent colitis-associated colon cancer. With the goal of isolating a single active compound, we further fractionated HAG, and found the most abundant molecule in this fraction was the polyacetylene, panaxynol (PA). After isolating and characterizing PA, we tested the efficacy of PA in the treatment and prevention of colitis in mice and studied the mechanism of action. We demonstrate here that PA effectively treats colitis in a Dextran Sulfate Sodium mouse model by targeting macrophages for DNA damage and apoptosis. This study provides additional mechanistic evidence that American ginseng can be used for conventional treatment of colitis and other diseases associated with macrophage dysfunction.

Panaxynol from Saposhnikovia diviaricata exhibits a hepatoprotective effect against lipopolysaccharide + D-Gal N induced acute liver injury by inhibiting Nf-κB/IκB-α and activating Nrf2/HO-1 signaling pathways

We investigated the mechanism of action of panaxynol (PAL) extract from the root of Saposhnikovia diviaricata (Turcz.) Schischk for treating acute liver injury caused by lipopolysaccharide (LPS) and D-galactosamine (D-Gal N) in mice. A mouse model of acute liver failure induced by LPS/D-Gal N was established. Mice were divided randomly into three equal groups: control group, LPS/D-Gal N group and PAL group. After seven days of continuous PAL administration, all animals except controls were injected with 50 μg/kg LPS and 800 mg/kg D-Gal N; blood and liver samples were collected after 8 h. Compared to the LPS/D-Gal N group, the levels of catalase, glutathione and superoxide dismutase were increased in the liver of the PAL group. The inflammatory response index indicated that PAL attenuated LPS/D Gal N-induced liver pathological injury and decreased levels of hepatic malondialdehyde, serum alanine aminotransferase, aspartate transaminase, tumor necrosis factor-α, and interleukins 1β and 6. PAL also inhibited LPS/D-Gal N induced nuclear factor-kappa B (Nf-κB), inhibitor kappa B-α (IκB-α) activation, and up-regulated Nrf2 and heme oxygenase-1 (HO-1) expression. PAL can prevent LPS/D-Gal N induced acute liver injury by activating Nrf2/HO-1 to stimulate antioxidant defense and inhibit the IkB-α/NF-κB signaling pathway.

Molecular mechanism of panaxydol on promoting axonal growth in PC12 cells

Nerve growth factor (NGF) promotes axonal growth in PC12 cells primarily by regulating the RTK-RAS-MEK-ERK pathway. Panaxydol, a polyacetylene isolated from Panax notoginseng, can mimic the effects of NGF. Panaxydol promotes neurite outgrowth in PC12 cells, but its molecular mechanism remains unclear. Indeed, although alkynol compounds such as panaxydol can increase intracellular cyclic adenosine 3',5'-monophosphate (cAMP) levels and the ERK inhibitor U0126 inhibits alkynol-induced axonal growth, how pathways downstream of cAMP activate ERK have not been investigated. This study observed the molecular mechanism of panaxydol-, NGF- and forskolin-induced PC12 cell axon growth using specific signaling pathway inhibitors. The results demonstrated that although the RTK inhibitor SU5416 obviously inhibited the growth-promoting effect of NGF, it could not inhibit the promoting effect of panaxydol on axonal growth of PC12 cells. The adenylate cyclase inhibitor SQ22536 and cAMP-dependent protein kinase inhibitor RpcAMPS could suppress the promoting effect of forskolin and panaxydol on axonal growth. The ERK inhibitor U0126 inhibited axonal growth induced by all three factors. However, the PKA inhibitor H89 inhibited the promoting effect of forskolin on axonal growth but could not suppress the promoting effect of panaxydol. A western blot assay was used to determine the effects of stimulating factors and inhibitors on ERK phosphorylation levels. The results revealed that NGF activates the ERK pathway through tyrosine receptors to induce axonal growth of PC12 cells. In contrast, panaxydol and forskolin increased cellular cAMP levels and were inhibited by adenylyl cyclase inhibitors. The protein kinase A inhibitor H89 completely inhibited forskolin-induced axonal outgrowth and ERK phosphorylation, but could not inhibit panaxydol-induced axonal growth and ERK phosphorylation. These results indicated that panaxydol promoted axonal growth of PC12 cells through different pathways downstream of cAMP. Considering that exchange protein directly activated by cAMP 1 (Epac1) plays an important role in mediating cAMP signaling pathways, RNA interference experiments targeting the Epac1 gene were employed. The results verified that Epac1 could mediate the axonal growth signaling pathway induced by panaxydol. These findings suggest that compared with NGF and forskolin, panaxydol elicits axonal growth through the cAMP-Epac1-Rap1-MEK-ERK-CREB pathway, which is independent of PKA.

Electroacupuncture Pretreatment Attenuates Cerebral Ischemic Injury via Notch Pathway-Mediated Up-Regulation of Hypoxia Inducible Factor-1α in Rats

We have reported electroacupuncture (EA) pretreatment induced the tolerance against focal cerebral ischemia through activation of canonical Notch pathway. However, the underlying mechanisms have not been fully understood. Evidences suggest that up-regulation of hypoxia inducible factor-1α (HIF-1α) contributes to neuroprotection against ischemia which could interact with Notch signaling pathway in this process. Therefore, the current study is to test that up-regulation of HIF-1α associated with Notch pathway contributes to the neuroprotection of EA pretreatment. Sprague–Dawley rats were treated with EA at the acupoint “Baihui (GV 20)” 30 min per day for successive 5 days before MCAO. HIF-1α levels were measured before and after reperfusion. Then, HIF-1α antagonist 2ME2 and γ-secretase inhibitor MW167 were used. Neurologic deficit scores, infarction volumes, neuronal apoptosis, and Bcl2/Bax were evaluated. HIF-1α and Notch1 intracellular domain (NICD) were assessed. The results showed EA pretreatment enhanced the neuronal expression of HIF-1α, reduced infarct volume, improved neurological outcome, inhibited neuronal apoptosis, up-regulated expression of Bcl-2, and down-regulated expression of Bax after reperfusion in the penumbra, while the beneficial effects were attenuated by 2ME2. Furthermore, intraventricular injection with MW167 efficiently suppressed both up-regulation of NICD and HIF-1α after reperfusion. However, administration with 2ME2 could only decrease the expression of HIF-1α in the penumbra. In conclusion, EA pretreatment exerts neuroprotection against ischemic injury through Notch pathway-mediated up-regulation of HIF-1α.

Biosynthesis of panaxynol and panaxydol in Panax ginseng

The natural formation of the bioactive C17-polyacetylenes (-)-(R)-panaxynol and panaxydol was analyzed by 13C-labeling experiments. For this purpose, plants of Panax ginseng were supplied with 13CO2 under field conditions or, alternatively, sterile root cultures of P. ginseng were supplemented with [U-13C6]glucose. The polyynes were isolated from the labeled roots or hairy root cultures, respectively, and analyzed by quantitative NMR spectroscopy. The same mixtures of eight doubly 13C-labeled isotopologues and one single labeled isotopologue were observed in the C17-polyacetylenes obtained from the two experiments. The polyketide-type labeling pattern is in line with the biosynthetic origin of the compounds via decarboxylation of fatty acids, probably of crepenynic acid. The 13C-study now provides experimental evidence for the biosynthesis of panaxynol and related polyacetylenes in P. ginseng under in planta conditions as well as in root cultures. The data also show that 13CO2 experiments under field conditions are useful to elucidate the biosynthetic pathways of metabolites, including those from roots.

Synthesis and biological evaluation of (--)-linarinic acid derivatives as neuroprotective agents against OGD-induced cell damage

A series of novel (-)-1,2,3,9-tetrahydropyrrolo[2,1-b]quinazoline-1-carboxylic acid derivatives were designed and synthesized. All of the prepared compounds were screened for their neuroprotective effects using an in vitro oxygen glucose deprivation (OGD) model of ischemic stroke. Some of the target compounds exhibited moderate to excellent protective potency. In particular, compounds 9d, 9e, 9g, and 9h showed significant protective effects in the SH-SY(5) Y cell line at all three concentrations tested.