Neuroprotective effect of lignans extracted from Eucommia ulmoides Oliv. on glaucoma-related neurodegeneration

AMPK and metabolic disorders: The opposite roles of dietary bioactive components and food contaminants

AMPK is a key player in a variety of metabolic and physiological processes, which might be considered one of the most promising targets for both prevention and treatment of metabolic syndrome and its associated diseases. Many dietary components and contaminants have been recently demonstrated to prevent or promote the development these diseases via AMPK-mediated pathways. AMPK can be activated by diverse phytochemical substances such as EGCG, chicoric acid, tomatidine, and others, all of which have been found to contribute to preventing or ameliorating chronic disorders. On the other hand, recent studies have found that metabolic disruptions induced by pesticides such as 1,3-Dichloro-2-propanol, imidacloprid, permethrin, are attributed to the inactivation of AMPK. This review may contribute to the development of functional foods for treatment of metabolic syndrome and associated diseases through modulating AMPK pathway.

Mechanism of cell death pathways in status epilepticus and related therapeutic agents

The most severe form of epilepsy, status epilepticus (SE), causes brain damage and results in the development of recurring seizures. Currently, the management of SE remains a clinical challenge because patients do not respond adequately to conventional treatments. Evidence suggests that neural cell death worsens the occurrence and progression of SE. The main forms of cell death are apoptosis, necroptosis, pyroptosis, and ferroptosis. Herein, these mechanisms of neuronal death in relation to SE and the alleviation of SE by potential modulators that target neuronal death have been reviewed. An understanding of these pathways and their possible roles in SE may assist in the development of SE therapies and in the discovery of new agents.

Traditional application and modern pharmacological research of Eucommia ulmoides Oliv

As a Traditional Chinese Medicine, Eucommia ulmoides Oliv. has been used for the treatment of various diseases since ancient times, involving lumbar pain, knee pain, osteoporosis, hepatoprotection, paralysis, intestinal haemorrhoids, vaginal bleeding, abortion, spermatorrhoea, foot fungus, anti-aging etc. With the developing discovery of E. ulmoides extracts and its active components in various pharmacological activities, E. ulmoides has gained more and more attention. Up to now, E. ulmoides has been revealed to show remarkable therapeutic effects on hypertension, hyperglycemia, diabetes, obesity, osteoporosis, Parkinson's disease, Alzheimer's disease, sexual dysfunction. E. ulmoides has also been reported to possess antioxidant, anti-inflammatory, neuroprotective, anti-fatigue, anti-aging, anti-cancer and immunoregulation activities etc. Along these lines, this review summarizes the traditional application and modern pharmacological research of E. ulmoides, providing novel insights of E. ulmoides in the treatment of various diseases.

Carboxymethylated chitosan alleviated oxidative stress injury in retinal ganglion cells via IncRNA-THOR/IGF2BP1 axis

BACKGROUND

Glaucoma is an advanced nerve disorder described by the deterioration of axon and RGCs. CMCS has been previously used as an anti-apoptotic and anti-oxidant agent.

OBJECTIVE

The current study aimed to explore the protective impact of CMCS against H2O2-induced injury in glaucoma in vitro.

METHODS

The relative expression of lncRNA THOR and the protein expression of IGF2BP1 in H2O2-induced RGC-5 cells were detected by RT-PCR and western blot methods respectively. The cell viability was measured using MTT assay while apoptosis rate was measured by flow cytometry. Moreover, ROS level was measured using ROS assay kit. Furthermore, the relations between THOR and IGF2BP1 were determined by using RNA pull-down.

RESULTS

The expression of THOR was reduced in H2O2-induced RGCs. Also, RGCs viability was inhibited while the level of ROS and cell apoptosis were enhanced. CMCS treatment considerably enhanced the expression of THOR and IGF2BP1 protein and cell viability but reduced ROS level and cell apoptosis. Moreover, IGF2BP1 protein was positively regulated by lncRNA THOR. CMCS protected the RGCs from oxidative stress via regulating lncRNA THOR/IGF2BP1.

CONCLUSION

CMCS enhanced the cell viability and reduced the cell apoptosis and ROS level and protected RGCs from oxidative stress via lncRNATHOR/IGF2BP1 pathway, potentially suggesting a new therapeutic strategy for the treatment of glaucoma.

Inhibition of Protein Kinase R by C16 Protects the Retinal Ganglion Cells from Hypoxia-induced Oxidative Stress, Inflammation, and Apoptosis

AIM/PURPOSE

Individually, hypoxia and protein kinase R (PKR) induce retinal ganglion cells (RGCs) damage by aggravating reactive oxygen species (ROS), oxidative stress, inflammation, and apoptosis. However, it is still not established in hypoxia mediates such damaging effect by modulating PKR. This study investigated the expression and activation of PKR in hypoxic RGCs and tested if suppression of PKR by C16 is protective.

MATERIALS AND METHODS

Isolated RGCs were under normoxic or hypoxic conditions for 12 h. In some cases, hypoxic cells were pre-treated with C16, a PKR inhibitor, or n-acetyl cysteine (NAC) a glutathione (GSH) precursor for 1 h and then exposed to hypoxia for the next 12 h.

RESULTS

Hypoxia increased cell death, lactate dehydrogenase (LDH) levels, and levels of single-stranded DNA (ssDNA). It also increased levels of ROS, the activity of the nuclear factor-kappa beta (NF-κB), JNK, and p38 MAPK, expression of Bax, p53, and cleaved caspase-3, levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and cytoplasmic levels of cytochrome-c. It concomitantly suppressed levels of GSH and Bcl-2. All these events were associated with increased phosphorylation (activation) of PKR and its target eukaryotic initiation factor 2 (eIF2). Pre-incubating the cells with NAC completely prevented all these effects in hypoxic cells. Similar protective effects without affecting levels of ROS and GSH levels were also seen in hypoxic cells pre-treated with C16.

CONCLUSION

Hypoxia induces oxidative stress, inflammation, and apoptosis in the RGCs mainly by ROS induced activation of PKR, whereas scavenging ROS by NAC or suppressing PKR by C16 is a novel protective mechanism.

Propofol enhanced the cell sensitivity to paclitaxel (PTX) in prostatic cancer (PC) through modulation of HOTAIR

BACKGROUND

PTX is widely used in cancer treatments.

OBJECTIVE

In this paper, we explored the role and potential molecular mechanism of propofol in regulating PTX sensitivity in PC cells.

METHODS

Prostatic cancer cell line PC3 was treated using different concentrations of PTX (10 nM, 50 nM), propofol (150 μM, 300 μM) or transfected with overexpressed HOTAIR plasmid. HOTAIR expression was analyzed by RT-qPCR. Apoptosis of PC3 cells was observed by flow cytometry method while cell viability was evaluated by CCK-8. Moreover, apoptosis-related genes, Bcl-2 and Bax were detected by Western blot methods. E-cadherin, N-cadherin and Vimentin protein concentrations were monitored by ELISA.

RESULTS

PTX significantly increased apoptosis of PC3 cells and reduced cell viability in a dose-dependent manner. Moreover, Protein expression of Bcl-2 was obviously inhibited while Bax protein expression level was provoked. Furthermore, E-cadherin protein concentration increased while N-cadherin and Vimentin decreased due to increasing PTX treatments. HOTAIR expression dropped due to PTX treatment while overexpression of HOTAIR induced cell viability, EMT and deterred apoptosis. Propofol ignited the PTX function while upregulation of HOTAIR partially reversed this.

CONCLUSION

Propofol enhanced paclitaxel sensitivity in prostatic cancer cells through modulation of HOTAIR in vitro.

Antioxidants for the Treatment of Retinal Disease: Summary of Recent Evidence

Retinal tissue is prone to oxidant burden and oxidative stress secondary to the generation of reactive oxygen species from high metabolic demand. The formation of reactive oxygen species occurs primarily from the mitochondrial respiratory chain as well as several enzymatic and oxidation reactions that occur in the neurosensory retina and retinal pigment epithelium. This oxidative stress has been implicated in the pathogenesis of several retinal diseases and the role of antioxidants as a therapeutic treatment shows promise in slowing the progression of certain diseases. The aim of this narrative review is to describe the mechanisms of retinal oxidative stress and summarize the current available evidence for antioxidants as a treatment for vitreoretinal disorders.

Phenolic compounds: current industrial applications, limitations and future challenges

Phenolic compounds are natural bioactive molecules found mainly in plant tissues that have shown interesting bioactivities, such as antioxidant, antimicrobial, anti-inflammatory, and antiproliferative activities, among others, which has led to great interest in their use by several industries. However, despite the large number of scientific studies on this topic, some issues still need to be studied and solved, such as the understanding of the main actions of these compounds in organisms. Besides their large potential applicability in industry, phenolic compounds still face some issues making it necessary to develop strategies to improve bioavailability, sustainable technologies of extraction and refinement, and stability procedures to increase the range of applicability. This review focuses on the most recent advances in the applications of phenolic compounds in different technological and medicinal areas. In addition, techniques to improve their sustainable resourcing, stability and bioavailability will be presented and discussed.

Augmented Buyang Huanwu Decoction facilitates axonal regeneration after peripheral nerve transection through the regulation of inflammatory cytokine production

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal formulation Buyang Huanwu Decoction (BYHWD) has been used to treat cardiovascular disorders including cerebral ischemia. Recent studies showed its effects on promoting axonal regeneration after nerve injury. However, compositional reformulation supplemented with herbal components that regulates inflammation may increase its efficacy for nerve repair.

AIM OF THE STUDY

We prepared a new herbal decoction by adding selected herbal components to BYHWD (augmented BYHWD; ABHD) and investigated the effect of ABHD on the production of inflammatory cytokines and axonal regeneration using an animal model of nerve transection and coaptation (NTC).

MATERIALS AND METHODS

A rat model of NTC was performed on the sciatic nerve. The sciatic nerve and dorsal root ganglion (DRG) were isolated and used for immunofluorescence staining and western blot analysis. DRG tissue was also used to prepare primary neuron culture and the length of neurites was analyzed. Sensorimotor nerve activities were assessed by rotarod and von Frey tests.

RESULTS

Three herbal components that facilitated neurite outgrowth were chosen to formulate ABHD. ABHD administration into the sciatic nerve 1 week or 3 months after NTC facilitated axonal regeneration. Cell division cycle 2 (Cdc2) and brain-derived neurotrophic factor (BDNF) proteins were induced from the reconnected distal portion of the sciatic nerve and the levels were further elevated by in vivo administration of ABHD. Phospho-Erk1/2 level was increased by ABHD treatment as well, implying its role in mediating retrograde transport of BDNF signals into the neuronal cell body. Production of inflammatory cytokines IL-1β and TNF-α was induced in the reconnected nerve but attenuated by ABHD treatment. Behavioral tests revealed that ABHD treatment improved functional recovery of sensorimotor activities.

CONCLUSIONS

A newly formulated ABHD is effective at regulating the production of inflammatory cytokines and promoting axonal regeneration after nerve transection and may be considered to develop therapeutic strategies for peripheral nerve injury disorders.

Chlorogenic acid protects PC12 cells against corticosterone-induced neurotoxicity related to inhibition of autophagy and apoptosis

BACKGROUND

There are evidences that chlorogenic acid (CGA) has antidepressant effects, however the underlying molecular mechanism has not been well understood. The aim of the study was to explore the neuroprotective effect of CGA on corticosterone (CORT)-induced PC 12 cells and its mechanism, especially the autophagy pathway.

METHODS

PC12 cells were incubated with CORT (0, 100, 200, 400 or 800 μM) for 24 h, cell viability was measured by MTT assay. PC12 cells were cultured with 400 μM of CORT in the absence or presence of CGA (25 μg/ml) for 24 h, morphologies and specific marker of autophagosome were observed by transmission electron microscope (TEM) and confocal immunofluorescence microscopy, respectively. In addition, PC12 cells were treated with different doses of CGA (0, 6.25, 12.5, 25 or 50 μg/ml) with or without CORT (400 μM) for 24 h, cell viability and changes in the morphology were observed, and further analysis of apoptotic and autophagic proteins, and expression of AKT/mTOR signaling pathway were carried out by Western blot. Specific inhibitors of autophagy 3-Methyladenine (3-MA) and chloroquine (CQ) were added to the PC12 cells cultures to explore the potential role of autophagy in CORT-induced neuronal cell apoptosis.

RESULTS

Besides decreasing PC12 cell activity, CORT could also induce autophagy and apoptosis of PC12 cells, while CGA could reverse these effects. In addition, CGA treatment regulated AKT/mTOR signaling pathway in PC12 cells. CGA, similar to 3-MA and QC, significantly inhibited CORT-induced apoptosis in PC12 cells.

CONCLUSIONS

Our results provide a new molecular mechanism for the treatment of CORT-induced neurotoxicity by CGA, and suggest CGA may be a potential substance which is can alleviate depression.

Ethnobotany, Phytochemistry and Pharmacological Properties of Eucommia ulmoides: A Review

Eucommia ulmoides Oliver, a single species of Eucommia genus belonging to the Eucommiaceae family, is an endemic in China and has been used in traditional Chinese medicine for nearly two thousand years. Records from different historical periods highlight E. ulmoides and its officinal botanical parts, usefulness in adaptation to disease and its central role in Chinese medicine theory. There are also historical collection documents for minorities in China. Tearing the leaves, bark and fruit produces strands of latex; a description of E. ulmoides’s morphological features is recorded in this paper. This review summarizes 204 natural compounds isolated from this plant, which are divided into seven categories: lignans, iridoids, flavonoids, phenols, steroids, terpenes and others. These components possess wide-ranging pharmacological efficacies, such as antihypertensive, antihyperglycemic, antihyperlipidemia, anti-oxidative, anti-osteoporosis, antitumor, immunomodulatory and neuroprotective activities. This review aims to provide a reference for extensive researches of E. ulmoides crude drugs, especially for quality control, biosynthesis and structure modification of active ingredients and pharmacological mechanism.

Reactive Oxygen Species-Mediated Damage of Retinal Neurons: Drug Development Targets for Therapies of Chronic Neurodegeneration of the Retina

The significance of oxidative stress in the development of chronic neurodegenerative diseases of the retina has become increasingly apparent in recent years. Reactive oxygen species (ROS) are free radicals produced at low levels as a result of normal cellular metabolism that are ultimately metabolized and detoxified by endogenous and exogenous mechanisms. In the presence of oxidative cellular stress, ROS are produced in excess, resulting in cellular injury and death and ultimately leading to tissue and organ dysfunction. Recent studies have investigated the role of excess ROS in the pathogenesis and development of chronic neurodegenerative diseases of the retina including glaucoma, diabetic retinopathy, and age-related macular degeneration. Findings from these studies are promising insofar as they provide clear rationales for innovative treatment and prevention strategies of these prevalent and disabling diseases where currently therapeutic options are limited. Here, we briefly outline recent developments that have contributed to our understanding of the role of ROS in the pathogenesis of chronic neurodegenerative diseases of the retina. We then examine and analyze the peer-reviewed evidence in support of ROS as targets for therapy development in the area of chronic neurodegeneration of the retina.

Eucommia ulmoides Oliver: A Potential Feedstock for Bioactive Products

Eucommia ulmoides Oliver (EUO), a traditional Chinese herb, contains a variety of bioactive chemicals, including lignans, iridoids, phenolics, steroids, terpenoids, flavonoids, etc. These bioactive chemicals possess the effective function in nourishing the liver and kidneys and regulating blood pressure. The composition of bioactive chemicals extracted from EUO vary in the different functional parts (leaves, seeds, bark, and staminate flower) and planting models. The bioactive parts of EUO are widely used as raw materials for medicine and food, powdery extracts, herbal formulations, and tinctures. These capabilities hold potential for future development and commercial exploitation of the bioactive products from EUO.

The Protective Effect of Aucubin from Eucommia ulmoides Against Status Epilepticus by Inducing Autophagy and Inhibiting Necroptosis

Eucommia ulmoides Oliv. is a famous traditional Chinese medicine which exhibits anti-oxidative stress ability and neuro-protective effects. Aucubin is the predominant component of Eucommia ulmoides Oliv. Our present study is intended to investigate aucubin's potential protective effects on neurons against epilepsy in the hippocampus by establishing the lithium-pilocarpine induced status epilepticus (SE) rat model in vivo. Aucubin (at a low dose and a high dose of 5[Formula: see text]mg/kg and 10[Formula: see text]mg/kg, respectively) was administered through gavage for two weeks before lithium-pilocarpine injection. Rats were sacrificed at 4, 24 and 72[Formula: see text]h after SE induction. Pretreatment with both low-dose and high-dose aucubin significantly reduced the number of death neurons ([Formula: see text]) and increased the number of surviving neurons ([Formula: see text]) in DG, Hilus, CA1 and CA3 hippocampal regions post SE. Meanwhile, it significantly inhibited necroptosis proteins (MLKL and RIP-1) ([Formula: see text] or [Formula: see text]) and enhanced autophagy protein (Beclin-1 and LC3BII/LC3BI) prevalence in the hippocampus ([Formula: see text] or [Formula: see text]). In conclusion, aucubin appeared to ameliorate damages in lithium-pilocarpine induced SE in hippocampus, reduce the number of apoptotic neurons, and increased the number of survival neurons by inducing autophagy and inhibiting necroptosis. These original findings might provide an important basis for the further investigation of the therapeutic role of aucubin in treatment or prevention of epilepsy-related neuronal damages.