Neuroprotective Effects of GV1001 in Animal Stroke Model and Neural Cells Subject to Oxygen-Glucose Deprivation/Reperfusion Injury

MicroRNA Regulation for Inflammasomes in High Glucose-Treated ARPE-19 Cells

Purpose

This study aimed to evaluate the expression of microRNAs (miRNAs) and inflammasomes in diabetes-induced retinal cells and to determine their role in the pathogenesis of diabetic retinopathy (DR).

Methods

To establish diabetes-induced cell models, ARPE-19 cells were treated with high glucose. The expression levels of five miRNAs (miR-185, miR-17, miR-20a, miR-15a, and miR-15b) were measured in high glucose-treated ARPE-19 cells using real-time quantitative polymerase chain reaction. Western blotting was performed to measure inflammasome expression in cellular models. miR-17 was selected as the target miRNA, and inflammasome expression was measured following the transfection of an miR-17 mimic into high glucose-treated ARPE-19 cells.

Results

In high glucose-treated ARPE-19 cells, miRNA expression was substantially downregulated, whereas that of inflammasome components was significantly increased. Following the transfection of the miR-17 mimic into high glucose-treated ARPE-19 cells, the levels of inflammasome components were significantly decreased.

Conclusions

This study investigated the relationship between miRNAs and inflammasomes in diabetes-induced cells using high glucose-treated ARPE-19 cells. These findings suggested that miR-17 suppresses inflammasomes, thereby reducing the subsequent inflammatory response and indicating that miRNAs and inflammasomes could serve as new therapeutic targets for DR.

Circular RNA circEfnb2 promotes cell injury after cerebral infarction by sponging miR-202-5p and regulating TRAF3 expression

BACKGROUND

Exogenous neural cell transplantation may be therapeutic for stroke, cerebral ischemic injury. Among other mechanisms, increasing findings indicated circular RNAs (circRNAs) regulate the pathogenesis progression of cerebral ischemia. Mmu_circ_0015034 (circEfnb2) was upregulated in focal cortical infarction established by middle cerebral artery occlusion (MCAO) in mice. Our study was designed to probe the molecular mechanism of circEfnb2 in the oxygen-glucose deprivation/reperfusion (OGD/R)-induced neuronal damage in cerebral ischemia.

METHODS

We established an in vitro OGD/R cell model. CircEfnb2 and microRNA-202-5p (miR-202-5p) levels were detected using real-time quantitative polymerase chain reaction (RT-qPCR). Lactate dehydrogenase (LDH), malondialdehyde (MDA), and reactive oxygen species (ROS) levels were assessed using specific kits. Tumor necrosis factor-α (TNF-α) and Interleukin-1β (IL-1β) levels were examined using an Enzyme-linked immunosorbent assay (ELISA). Flow cytometry analysis evaluated cell apoptosis. Protein levels of B-cell lymphoma-2 (Bcl-2), Bcl-2 related X protein (Bax), cleaved caspase 3, and Tumor necrosis factor receptor-associated factor 3 (TRAF3) were determined using Western blot assay.

RESULTS

Overall, circEfnb2 was highly expressed whereas miR-202-5p was decreased in OGD/R-treated mouse hippocampal neuronal HT22 cells compared to normal controls (both p > 0.05). From an in vitro functional perspective, circEfnb2 knockdown attenuated an OGD/R-triggered neuronal injury compared to controls (p > 0.05). Mechanically, circEfnb2 acted as a sponge of miR-202-5p; downregulation of miR-202-5p annulled the inhibitory roles of circEfnb2 silencing in an OGD/R-caused neuronal injury model. Our analysis showed that miR-202-5p directly targeted TRAF3 as enhanced TRAF3 abolished the effects of miR-202-5p in the OGD/R-induced neuronal injury. In vivo, lentivirus with a short hairpin (sh)-circEfnb2 inhibited cerebral injury, when injected into cerebral cortex in MCAO mice (p > 0.05).

CONCLUSION

Our results suggest that circEfnb2 deficiency may decrease OGD/R-induced HT22 cell damage by modulating the miR-202-5p/TRAF3 axis. This explanation may provide a new direction for cerebral infarction potential therapeutic targets.

GV1001 reduces neurodegeneration and prolongs lifespan in 3xTg-AD mouse model through anti-aging effects

GV1001, which mimics the activity of human telomerase reverse transcriptase, protects neural cells from amyloid beta (Aβ) toxicity and other stressors through extra-telomeric function, as noted in our prior in vitro studies. As per a recent phase II clinical trial, it improves cognitive function in patients with moderate to severe dementia. However, the underlying protective mechanisms remain unclear. This study aimed to investigate the effects of GV1001 on neurodegeneration, senescence, and survival in triple transgenic Alzheimer's disease (3xTg-AD) mice. GV1001 (1 mg/kg) was subcutaneously injected into old 3xTg-AD mice thrice a week until the endpoint for sacrifice, and survival was analysed. Magnetic resonance imaging (MRI) and Prussian blue staining (PBS) were performed to evaluate entry of GV1001 entrance into the brain. Diverse molecular studies were performed to investigate the effect of GV1001 on neurodegeneration and cellular senescence in AD model mice, with a particular focus on BACE, amyloid beta1-42 (Aβ1-42), phosphorylated tau, volume of dentate gyrus, β-galactosidase positive cells, telomere length, telomerase activity, and ageing-associated proteins. GV1001 crossed the blood-brain barrier, as confirmed by assessing the status of ferrocenecarboxylic acid-conjugated GV1001 using magnetic resonance imaging and PBS. GV1001 increased the survival of 3xTg-AD mice. It decreased BACE and Aβ1-42 levels, neurodegeneration (i.e., reduced CA1, CA3 and dentate gyrus volume, decreased levels of senescence-associated β-galactosidase positive cells, and increased telomere length and telomerase activity), and levels of ageing-associated proteins. We suggest that GV1001 exerts anti-ageing effects in 3xTg-AD mice by reducing neurodegeneration and senescence, which contributes to improved survival.

Exploring the Causal Relationship Between Telomere Biology and Alzheimer's Disease

Telomeres, also known as the "protective caps" of our chromosomes, shorten with each cell cycle due to the end replication problem. This process, termed telomere attrition, is associated with many age-related disorders, such as Alzheimer's disease (AD). Despite the numerous studies conducted in this field, the role of telomere attrition in the onset of the disease remains unclear. To investigate the causal relationship between short telomeres and AD, this review aims to highlight the primary factors that regulate telomere length and maintain its integrity, with an additional outlook on the role of oxidative stress, which is commonly associated with aging and molecular damage. Although some findings thus far might be contradictory, telomere attrition likely plays a crucial role in the progression of AD due to its close association with oxidative stress. The currently available treatments for AD are only symptomatic without affecting the progression of the disease. The components of telomere biology discussed in this paper have previously been studied as an alternative treatment option for several diseases and have exhibited promising in vitro and in vivo results. Hence, this should provide a basis for future research to develop a potential therapeutic strategy for AD. (Created with BioRender.com).