Neuroprotective effects of Tiaogeng decoction against H2O2-induced oxidative injury and apoptosis in PC12 cells via Nrf2 and JNK signaling pathways

Inhibition of JNK transcription via the Nrf2/Keap1a pathway to resist microcystin-induced oxidative stress and apoptosis in freshwater mussels Cristaria plicata

With global warming and increasing eutrophication of water bodies, a variety of algal toxins, including microcystin (MC), released into water by cyanobacterial blooms pose a serious threat to the survival of aquatic organisms. To investigate the mechanism of the Nrf2/Keap1a pathway on resisting MC-induced oxidative stress and apoptosis in Cristata plicata, we cloned the full-length cDNA of CpBcl-2. The cDNA full-length of CpBcl-2 was 760 bp, encoded a 177 amino acid peptide, and contained a highly conserved Bcl-2-like superfamily domain. MC stimulation increased the expression and activity levels of related antioxidant enzymes. After CpNrf2 knockdown, the transcription levels of NAD(P)H quinone redox Enzyme-1 (NQO1) and related antioxidant enzymes activity in the gills and kidney of C. plicata were significantly down-regulated upon MC stress, but that was significantly upregulated after knockdown of CpKeap1a. Additionally, Upon MC stress, the mRNA levels of CpBcl-2 were increased in the gills and kidney after knockdown of CpNrf2 at 24 h, and that of CpBcl-2 were decreased at 72 and 96 h in the CpKeap1a-siRNA+MC group. Moreover, MC stimulation significantly inhibited CpJNK expression in the gills and kidney, but which regulated the Nrf2/Keap1a pathway in C. plicata. However, the JNK inhibitor SP600125 promoted the expression of CpNrf2 and related enzymes with antioxidant response element (ARE-driven enzyme) in the gills and kidney. Then, we speculated that CpKeap1a was a negative regulator of CpNrf2, and C. plicata resisted MC-induced oxidative damage and apoptosis by inhibiting JNK transcription via the Nrf2/Keap1a pathway.

Recent advances in reactive oxygen species scavenging nanomaterials for wound healing

Reactive oxygen species play a crucial role in cell signaling pathways during wound healing phases. Treatment strategies to balance the redox level in the deep wound tissue are emerging for wound management. In recent years, reactive oxygen species scavenging agents including natural antioxidants, reactive oxygen species (ROS) scavenging nanozymes, and antioxidant delivery systems have been widely employed to inhibit oxidative stress and promote skin regeneration. Here, the importance of reactive oxygen species in different wound healing phases is critically analyzed. Various cutting-edge bioactive ROS nanoscavengers and antioxidant delivery platforms are discussed. This review also highlights the future directions for wound therapies via reactive oxygen species scavenging. This comprehensive review offers a map of the research on ROS scavengers with redox balancing mechanisms of action in the wound healing process, which benefits development and clinical applications of next-generation ROS scavenging-based nanomaterials in skin regeneration.

A Novel Quercetin Encapsulated Glucose Modified Liposome and Its Brain-Target Antioxidative Neuroprotection Effects

Neurodegenerative diseases (NDDs) are mainly induced by oxidative stress which produces excessive reactive oxygen species (ROS). Quercetin (QU) is a potent antioxidant with some effects on NDDs. This study prepared and characterized a novel glucose-modified QU liposome (QU-Glu-Lip), aiming not only to overcome QU's poor water solubility and bioavailability but also to deliver more QU to brain tissue to enhance its neuroprotective effect. QU-Glu-Lip possessed encapsulation efficiency (EE) of 89.9%, homogenous particle sizes (116-124 nm), small PDI value (<0.3), zeta value -1.363 ± 0.437 mV, proper pH and salt stability, and proper cytotoxicity. The glucose-modified liposome penetrated the blood-brain barrier (BBB) mediated via the glucose transporter 1 (GLUT1) and was taken by neuronal cells more efficiently than liposome without glucose, according to bEnd.3 and PC12 cell tests. QU-Glu-Lip attenuated H2O2-induced oxidative damage to PC12 with higher cell viability (88.42%) and lower intracellular ROS compared to that of QU. QU-Glu-Lip had higher brain target ability and delivered more QU to neuronal cells, effectively exerting the antioxidative neuroprotection effect. There is potential for the QU-Glu-Lip application for more effective treatment of NDDs.

Piceatannol protects rat neuron cells from oxygen-glucose deprivation reperfusion injury via regulation of GSK-3β/Nrf2 signaling pathway

OBJECTIVE

To investigate the effect and mechanism of piceatannol on cerebral ischemia-reperfusion injury.

METHODS

The oxygen-glucose deprivation reperfusion (OGD/R) model was constructed in primary cultured suckling rat cortical neuron cells. After 2 h of oxygen-glucose deprivation, the cells were treated with piceatannol for 24 h. The cell survival rate was detected by MTT assay, and the degree of cell damage was detected by intracellular lactate dehydrogenase (LDH) release assay. The activity of superoxide dismutase (SOD) and the content of adenosine triphosphate (ATP) were detected by colorimetric method. The content of reactive oxygen species (ROS) was detected by flow cytometry or observed with inverted fluorescence microscope. The ultrastructure of mitochondria was observed with transmission electron microscopy. Western blotting was used to detect the phosphorylation levels of protein kinase B (AKT) and glycogen synthase kinase (GSK)-3β. Immunofluorescence staining was used to observe the nuclear localization of nuclear factor-erythroid 2-related factor (Nrf) 2. After OGD/R neuron cells were pretreated with Nrf2 inhibitor ML385 for 24 h, the effect of Nrf2 on the improvement of cell activity and antioxidant activity of piceatannol were investigated. Western blotting was used to detect the protein expression levels of Nrf2, heme oxygenase (HO) 1 and NADPH quinone oxidoreductase (NQO) 1.

RESULTS

Piceatannol significantly increased the survival rate of OGD/R neurons, decreased LDH release and reactive oxygen species content, increased SOD activity, ameliorated mitochondrial ultrastructural damage, increased mitochondrial membrane potential and ATP level (all P<0.05), increased phosphorylation of AKT and GSK-3β protein, up-regulated the expression of Nrf2, HO-1 and NQO1 protein, increased the nuclear-to-plasma ratio of Nrf2, and promoted the nuclear transfer of Nrf2 (all P<0.05). ML385 could significantly reverse the rescue effect of paclitaxel on the model cells and the regulatory activities of SOD, ROS and LDH (all P<0.05).

CONCLUSION

Piceatannol can regulate Nrf2 by activating GSK-3β signaling pathway, promote its nuclear translocation, exert corresponding antioxidant effect, and protect mitochondrial structure and function in rat neuron cells.

Delavatine A attenuates OGD/R-caused PC12 cell injury and apoptosis through suppressing the MKK7/JNK signaling pathway

Delavatine A (DA) is an unusual isoquinoline alkaloid with a novel skeleton isolated from Chinese folk medicine Incarvillea delavayi. Studies conducted in our lab have demonstrated that DA has potential anti-inflammatory activity in LPS-treated BV-2 cells. DA, however, has not been studied for its protective effect on neuronal cells yet. Thus, to explore whether DA can protect neurons, oxygen and glucose deprivation/reperfusion (OGD/R)-injured PC12 cell and middle cerebral artery occlusion/reperfusion (MCAO/R) rat model were used to assess the protective efficacy of DA against OGD/R damaged PC12 cells and MCAO/R injured rats. Our results demonstrated that DA pretreatment (0.31-2.5 μM) dose-dependently increased cell survival and mitochondrial membrane potential (MMP), whereas it lowered the leakage of lactate dehydrogenase (LDH), intracellular cumulation of Ca²⁺, and overproduction of reactive oxygen species (ROS), and inhibited the apoptosis rate in OGD/R-injured PC12 cells. Western blot demonstrated that DA pretreatment lowered the expression of apoptotic proteins and repressed the activation of the MKK7/JNK pathway. It was also found that the neuroprotective efficacy of DA was significantly reversed by co-treatment with the JNK agonist anisomycin, suggesting that DA reduced PC12 cell injury and apoptosis by suppressing the MKK7/JNK pathway. Furthermore, DA oral administration greatly alleviated the neurological dysfunction and reduced the infarct volume of MCAO/R rats. Taken together, DA could ameliorate OGD/R-caused PC12 cell injury and improve brain ischemia/reperfusion (I/R) damage in MCAO/R rats, and its neuroprotection might be attributed to suppressing the MKK7/JNK signaling pathway.

Thermosensitive Hydrogel Incorporating Prussian Blue Nanoparticles Promotes Diabetic Wound Healing via ROS Scavenging and Mitochondrial Function Restoration

Diabetic foot ulcer is a serious complication in diabetes patients, imposing a serious physical and economic burden to patients and to the healthcare system as a whole. Oxidative stress is thought to be a key driver of the pathogenesis of such ulcers. However, no antioxidant drugs have received clinical approval to date, underscoring the need for the further development of such medications. Hydrogels can be applied directly to the wound site, wherein they function to prevent infection and maintain local moisture concentrations, in addition to serving as a reservoir for the delivery of a range of therapeutic compounds with the potential to expedite wound healing in a synergistic manner. Herein, we synthesized Prussian blue nanoparticles (PBNPs) capable of efficiently scavenging reactive oxygen species (ROS) owing to their ability to mimic the activity of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD). In the context of in vitro oxidative stress, these PBNPs were able to protect against cytotoxicity, protect mitochondria from oxidative stress-related damage, and restore nuclear factor erythroid 2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) pathway activity. To expand on these results in an in vivo context, we prepared a thermosensitive poly (d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (PDLLA-PEG-PDLLA) hydrogel (PLEL)-based wound dressing in which PBNPs had been homogenously incorporated, and we then used this dressing as a platform for controlled PBNP release. The resultant PBNPs@PLEL wound dressing was able to improve diabetic wound healing, decrease ROS production, promote angiogenesis, and reduce pro-inflammatory interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels within diabetic wounds. Overall, our results suggest that this PBNPs@PLEL platform holds great promise as a treatment for diabetic foot ulcers.