Nischarin attenuates apoptosis induced by oxidative stress in PC12 cells

Neuroprotective Effect of Abelmoschus manihot Flower Extracts against the H2O2-Induced Cytotoxicity, Oxidative Stress and Inflammation in PC12 Cells

The progression of neurodegenerative diseases is associated with oxidative stress and inflammatory responses. Abelmoschus manihot L. flower (AMf) has been shown to possess excellent antioxidant and anti-inflammatory activities. This study investigated the protective effect of ethanolic extract (AME), water extract (AMW) and supercritical extract (AMS) of AMf on PC12 neuronal cells under hydrogen peroxide (H2O2) stimulation. This study also explored the molecular mechanism underlying the protective effect of AME, which was the best among the three extracts. The experimental results showed that even at a concentration of 500 μg/mL, neither AME nor AMW showed toxic effects on PC12 cells, while AMS caused about 10% cell death. AME has the most protective effect on apoptosis of PC12 cells stimulated with 0.5 mM H2O2. This is evident by the finding when PC12 cells were treated with 500 μg/mL AME; the viability was restored from 58.7% to 80.6% in the Treatment mode (p < 0.001) and from 59.1% to 98.1% in the Prevention mode (p < 0.001). Under the stimulation of H2O2, AME significantly up-regulated the expression of antioxidant enzymes, such as catalase, glutathione peroxidase and superoxide dismutase; promoted the production of the intracellular antioxidant; reduced glutathione; and reduced ROS generation in PC12 cells. When the acute inflammation was induced under the H2O2 stimulation, AME significantly down-regulated the pro-inflammatory cytokines and mediators (e.g., TNF-α, IL-1β, IL-6, COX-2 and iNOS). AME pretreatment could also greatly promote the production of nucleotide excision repair (NER)-related proteins, which were down-regulated by H2O2. This finding indicates that AME could repair DNA damage caused by oxidative stress. Results from this study demonstrate that AME has the potential to delay the onset and progression of oxidative stress-induced neurodegenerative diseases.

Characterization of the Cellular Microenvironment and Novel Specific Biomarkers in Pterygia Using RNA Sequencing

With a worldwide prevalence of ~12%, pterygium is a common degenerative and environmentally triggered ocular surface disorder characterized by wing-shaped growth of conjunctival tissue onto the cornea that can lead to blindness if left untreated. This study characterizes the transcriptional profile and the cellular microenvironment of conjunctival pterygia and identifies novel pterygia-specific biomarkers. Formalin-fixed and paraffin-embedded pterygia as well as healthy conjunctival specimens were analyzed using MACE RNA sequencing (n = 8 each) and immunohistochemistry (pterygia n = 7, control n = 3). According to the bioinformatic cell type enrichment analysis using xCell, the cellular microenvironment of pterygia was characterized by an enrichment of myofibroblasts, T-lymphocytes and various antigen-presenting cells, including dendritic cells and macrophages. Differentially expressed genes that were increased in pterygia compared to control tissue were mainly involved in autophagy (including DCN, TMBIM6), cellular response to stress (including TPT1, DDX5) as well as fibroblast proliferation and epithelial to mesenchymal transition (including CTNNB1, TGFBR1, and FN1). Immunohistochemical analysis confirmed a significantly increased FN1 stromal immunoreactivity in pterygia when compared to control tissue. In addition, a variety of factors involved in apoptosis were significantly downregulated in pterygia, including LCN2, CTSD, and NISCH. Furthermore, 450 pterygia-specific biomarkers were identified by including transcriptional data of different ocular surface pathologies serving as controls (training group), which were then validated using transcriptional data of cultured human pterygium cells. Among the most pterygia-specific factors were transcripts such as AHNAK, RTN4, TPT1, FSTL1, and SPARC. Immunohistochemical validation of SPARC revealed a significantly increased stromal immunoreactivity in pterygia when compared to controls, most notably in vessels and intravascular vessel wall-adherent mononuclear cells. Taken together, the present study provides new insights into the cellular microenvironment and the transcriptional profile of pterygia, identifies new and specific biomarkers and in addition to fibrosis-related genes, uncovers autophagy, stress response and apoptosis modulation as pterygium-associated processes. These findings expand our understanding of the pathophysiology of pterygia, provide new diagnostic tools, and may enable new targeted therapeutic options for this common and sight-threatening ocular surface disease.

Transcription factor KLF15 inhibits the proliferation and migration of gastric cancer cells via regulating the TFAP2A-AS1/NISCH axis

BACKGROUND

Recently, overwhelming evidence supports that long noncoding RNAs (lncRNAs) play crucial roles in the occurrence and progression of tumors. However, the role and mechanism of lncRNA TFAP2A-AS1 in human gastric cancer (GC) remains unclear. Thus, the biological role and regulatory mechanisms of TFAP2A-AS1 in GC were explored.

METHODS

Quantitative real-time PCR (qPCR) was applied to detect gene expression. Western blot was used to measure protein expression. Cell proliferation and migration were determined by functional assays. Fluorescence in situ hybridization (FISH) assays were performed to determine the subcellular distribution of TFAP2A-AS1 in GC. Mechanism investigations were conducted to explore the downstream genes of TFAP2A-AS1 and the upstream transcription factor of TFAP2A-AS1 in GC cells.

RESULTS

TFAP2A-AS1 inhibits the proliferation and migration of GC cells. In the downstream regulation mechanism, miR-3657 was verified as the downstream gene of TFAP2A-AS1 and NISCH as the target of miR-3657. NISCH also suppresses cell proliferation and migration in GC. In the upstream regulation mechanism, transcription factor KLF15 positively mediates TFAP2A-AS1 to suppress GC cell proliferation and migration.

CONCLUSION

KLF15-mediated TFAP2A-AS1 hampers cell proliferation and migration in GC via miR-3657/NISCH axis.

Neuroprotective effect of apigenin against cerebral ischemia/reperfusion injury

Objective

The therapeutic efficacy of apigenin in PC12 cells and rats remains uncertain. The aim of this study was to investigate the neuroprotective effects of apigenin against cerebral ischemia/reperfusion injury, both in vitro and in vivo.

Methods

We first treated PC12 cells with cobalt chloride (CoCl₂) to create a model of oxidative stress injury. Cell viability was then determined using a multifunctional microplate reader. In addition, reactive oxygen species (ROS) levels, apoptosis, and mitochondrial membrane potentials (MMPs) were examined using high-content cytometer analysis. The efficacy of apigenin treatment was also analyzed in a rat middle cerebral artery occlusion (MCAO) model using TTC staining and neurological deficit scores.

Results

The half-inhibitory concentration of CoCl₂ was 1.2 mM. Pretreatment with 10 µg ⋅ mL⁻¹ apigenin significantly enhanced cell viability, reduced ROS levels, alleviated apoptosis, and improved MMP in PC12 cells with CoCl₂-induced injury in vitro. In addition, apigenin treatment in vivo significantly improved neurological deficit scores and reduced infarct areas in MCAO rats. These results suggest that the neuroprotective mechanisms of apigenin may be related to mitochondrial activation.

Conclusions

Apigenin had excellent neuroprotective effects for the treatment of cerebral ischemia/reperfusion injury in vitro and in vivo.

N‑linoleyltyrosine protects PC12 cells against oxidative damage via autophagy: Possible involvement of CB1 receptor regulation

Oxidative stress is one of the main pathogenic factors of neurodegenerative diseases. As the ligand of cannabinoid type 1 (CB1) and 2 (CB2) receptors, anandamide (AEA) exerts benign antioxidant activities. However, the instability of AEA results in low levels in vivo, which limit its further application. Based on the structure of AEA, N‑linoleyltyrosine (NITyr) was synthesized in our laboratory and was hypothesized to possess a similar function to that of AEA. To the best of our knowledge, the present study demonstrates for the first time, the activities and mechanisms of NITyr. NITyr treatment attenuated hydrogen peroxide (H2O2)‑induced cytotoxicity, with the most promiment effect observed at 1 µmol/l. Treatment with NITyr also suppressed the H2O2‑induced elevation of reactive oxygen species (ROS) and enhanced the expression of the autophagy‑related proteins, LC3‑II, beclin‑1, ATG 5 and ATG13. The autophagic inhibitor, 3‑methyladenine, reversed the effects of NITyr on ROS levels and cellular viability. Furthermore, AM251, a CB1 receptor antagonist, but not AM630 (a CB2 receptor antagonist), diminished the effects of NITyr on cell viability, ROS generation and autophagy‑related protein expression. However, NITyr increased the protein expression of both the CB1 and CB2 receptors. Therefore, NITyr was concluded to protect PC12 cells against H2O2‑induced oxidative injury by inducing autophagy, a process which may involve the CB1 receptor.

Neuroprotective Function of a Novel Hexapeptide QMDDQ from Shrimp via Activation of the PKA/CREB/BNDF Signaling Pathway and Its Structure-Activity Relationship

This study aimed to evaluate the neuroprotective function of shrimp-derived peptides QMDDQ and KMDDQ. Biochemical results revealed that both peptides exhibited neuroprotective effects by increasing acetylcholine (ACh) content and inhibiting acetylcholinesterase (AChE) activity in PC12 cells; QMDDQ was more active than KMDDQ. COSY-NOESY spectroscopic data showed that the superior neuroprotective function of QMDDQ might be attributed to its N-terminal glutamine as it exhibited an extended spatial conformation, facilitating its interactions with AChE. QMDDQ can promote the basic energy metabolism of cells more than KMDDQ. The peptides showed neuroprotective ability due to the activation of the antiapoptosis and PKA/CREB/BNDF signaling pathway. QMDDQ was selected to investigate its memory-enhancing activity in scopolamine-induced amnesic mice, revealing memory protection in mice, as it improved their performance in the Morris water maze experiment. In addition, QMDDQ increased ACh content (4.98 ± 0.51 μg/mg prot) and decreased AChE activity (4.72 ± 0.11 U/mg prot) in the mouse hippocampus. These data indicate the systemic mechanism through which naturally derived QMDDQ improved neuroprotection and memory ability.

The Emerging Role of lncRNAs in Spinal Cord Injury

Spinal cord injury (SCI) is a highly debilitating disease and is increasingly being recognized as an important global health priority. However, the mechanisms underlying SCI have not yet been fully elucidated, and effective therapies for SCI are lacking. Long noncoding RNAs (lncRNAs), which form a major class of noncoding RNAs, have emerged as novel targets for regulating several physiological functions and mediating numerous neurological diseases. Notably, gene expression profile analyses have demonstrated aberrant changes in lncRNA expression in rats or mice after traumatic or nontraumatic SCI. LncRNAs have been shown to be associated with multiple pathophysiological processes following SCI including inflammation, neural apoptosis, and oxidative stress. They also play a crucial role in the complications associated with SCI, such as neuropathic pain. At the same time, some lncRNAs have been found to be therapeutic targets for neural stem cell transplantation and hydrogen sulfide treatment aimed at alleviating SCI. Therefore, lncRNAs could be promising biomarkers for the diagnosis, treatment, and prognosis of SCI. However, further researches are required to clarify the therapeutic effects of lncRNAs on SCI and the mechanisms underlying these effects. In this study, we reviewed the current progress of the studies on the involvement of lncRNAs in SCI, with the aim of drawing attention towards their roles in this debilitating condition.