MiR-216a-5p ameliorates learning-memory deficits and neuroinflammatory response of Alzheimer's disease mice via regulation of HMGB1/NF-κB signaling

Ginsenoside Rg3 induces mesangial cells proliferation and attenuates apoptosis by miR-216a-5p/MAPK pathway in diabetic kidney disease

BACKGROUND

Ginsenoside Rg3 is an active saponin isolated from ginseng, which can reduce renal inflammation. However, the role and mechanism of Rg3 in diabetic kidney disease (DKD) are far from being studied.

METHODS

The effects of Rg3 and miR-216a-5p on the proliferation, apoptosis, and MAPK pathway in high glucose (HG)-induced SV40 MES 13 were monitored by CCK-8, TUNEL staining, and western blot.

RESULTS

Rg3 treatment could accelerate proliferation and suppress apoptosis in HG-induced SV40 MES. Moreover, miR-216a-5p inhibition also could alleviate renal injury, prevent apoptosis, and activate the MAPK pathway in kidney tissues of diabetic model mice.

CONCLUSION

Rg3 could attenuate DKD progression by downregulating miR-216a-5p, suggesting Rg3 and miR-216a-5p might be the potential drug and molecular targets for DKD therapy.

NcRNAs: A synergistically antiapoptosis therapeutic tool in Alzheimer's disease

AIMS

The aim of this review is to systematically summarize and analyze the noncoding RNAs (ncRNAs), especially microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), in the cell apoptosis among Alzheimer's disease (AD) in recent years to demonstrate their value in the diagnosis and treatment of AD.

METHODS

We systematically summarized in vitro and in vivo studies focusing on the ncRNAs in the regulation of cell apoptosis among AD in PubMed, ScienceDirect, and Google Scholar.

RESULTS

We discover three patterns of ncRNAs (including 'miRNA-mRNA', 'lncRNA-miRNA-mRNA', and 'circRNA-miRNA-mRNA') form the ncRNA-based regulatory networks in regulating cell apoptosis in AD.

CONCLUSIONS

This review provides a future diagnosis and treatment strategy for AD patients based on ncRNAs.

Age-Dependent and Aβ-Induced Dynamic Changes in the Subcellular Localization of HMGB1 in Neurons and Microglia in the Brains of an Animal Model of Alzheimer's Disease

HMGB1 is a prototypical danger-associated molecular pattern (DAMP) molecule that co-localizes with amyloid beta (Aβ) in the brains of patients with Alzheimer's disease. HMGB1 levels are significantly higher in the cerebrospinal fluid of patients. However, the cellular and subcellular distribution of HMGB1 in relation to the pathology of Alzheimer's disease has not yet been studied in detail. Here, we investigated whether HMGB1 protein levels in brain tissue homogenates (frontal cortex and striatum) and sera from Tg-APP/PS1 mice, along with its cellular and subcellular localization in those regions, differed. Total HMGB1 levels were increased in the frontal cortices of aged wildtype (7.5 M) mice compared to young (3.5 M) mice, whereas total HMGB1 levels in the frontal cortices of Tg-APP/PS1 mice (7.5 M) were significantly lower than those in age-matched wildtype mice. In contrast, total serum HMGB1 levels were enhanced in aged wildtype (7.5 M) mice and Tg-APP/PS1 mice (7.5 M). Further analysis indicated that nuclear HMGB1 levels in the frontal cortices of Tg-APP/PS1 mice were significantly reduced compared to those in age-matched wildtype controls, and cytosolic HMGB1 levels were also significantly decreased. Triple-fluorescence immunohistochemical analysis indicated that HMGB1 appeared as a ring shape in the cytoplasm of most neurons and microglia in the frontal cortices of 9.5 M Tg-APP/PS1 mice, indicating that nuclear HMGB1 is reduced by aging and in Tg-APP/PS1 mice. Consistent with these observations, Aβ treatment of both primary cortical neuron and primary microglial cultures increased HMGB1 secretion in the media, in an Aβ-dose-dependent manner. Our results indicate that nuclear HMGB1 might be translocated from the nucleus to the cytoplasm in both neurons and microglia in the brains of Tg-APP/PS1 mice, and that it may subsequently be secreted extracellularly.

Mechanism and Therapeutic Prospect of miRNAs in Neurodegenerative Diseases

MicroRNAs (miRNAs) are the smallest class of noncoding RNAs, which widely exist in animals and plants. They can inhibit translation or overexpression by combining with mRNA and participate in posttranscriptional regulation of genes, resulting in reduced expression of target proteins, affecting the development, growth, aging, metabolism, and other physiological and pathological processes of animals and plants. It is a powerful negative regulator of gene expression. It mediates the information exchange between different cellular pathways in cellular homeostasis and stress response and regulates the differentiation, plasticity, and neurotransmission of neurons. In neurodegenerative diseases, in addition to the complex interactions between genetic susceptibility and environmental factors, miRNAs can serve as a promising diagnostic tool for diseases. They can also increase or reduce neuronal damage by regulating the body's signaling pathways, immune system, stem cells, gut microbiota, etc. They can not only affect the occurrence of diseases and exacerbate disease progression but also promote neuronal repair and reduce apoptosis, to prevent and slow down the development of diseases. This article reviews the research progress of miRNAs on the mechanism and treatment of neurodegenerative diseases in the nervous system. This trial is registered with NCT01819545, NCT02129452, NCT04120493, NCT04840823, NCT02253732, NCT02045056, NCT03388242, NCT01992029, NCT04961450, NCT03088839, NCT04137926, NCT02283073, NCT04509271, NCT02859428, and NCT05243017.

Bone marrow mesenchymal stem cell exosomes-derived microRNA-216a-5p on locomotor performance, neuronal injury, and microglia inflammation in spinal cord injury

Background: MicroRNA-216a-5p (miR-216a-5p) mediates inflammatory responses and neuronal injury to participate in the pathology of spinal cord injury (SCI). This study intended to explore the engagement of bone marrow mesenchymal stem cell exosomes (BMSC-Exo)-derived miR-216a-5p in locomotor performance, neuronal injury, and microglia-mediated inflammation in SCI rats. Methods: Rat BMSC or BMSC-Exo was injected into SCI rats. GW4869 treatment was adopted to suppress the exosome secretion from BMSC. Subsequently, miR-216a-5p-overexpressed BMSC-Exo (BMSC-miR-Exo) or negative-control-overexpressed BMSC-Exo (BMSC-NC-Exo) were injected into SCI rats. Results: The injection of BMSC or BMSC-Exo enhanced locomotor performance reflected by Basso, Beattie & Bresnahan score (p < 0.001), and neuronal viability reflected by NeuN+ cells (p < 0.01), but attenuated neuronal apoptosis reflected by TUNEL positive rate, cleaved-caspase-3 expression, and B-cell leukemia/lymphoma-2 expression (p < 0.05). Additionally, the injection of BMSC or BMSC-Exo suppressed microglia M1 polarization-mediated inflammation reflected by IBA1+iNOS+ cells, tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 (p < 0.01). Notably, the effect of BMSC on the above functions was retarded by the GW4869 treatment (most p < 0.05). Subsequently, the injection of BMSC-miR-Exo further improved locomotor performance (p < 0.05), while inhibiting neuronal apoptosis (p < 0.05) and microglia M1 polarization-mediated inflammation (p < 0.05) compared to BMSC-NC-Exo. Interestingly, the injection of BMSC-miR-Exo reduced toll-like receptor 4 (TLR4) (p < 0.01), myeloid differentiation factor 88 (p < 0.05), and nuclear factor kappa B (NF-κB) (p < 0.05) expressions versus BMSC-NC-Exo. Conclusion: BMSC-Exo-derived miR-216a-5p enhances functional recovery by attenuating neuronal injury and microglia-mediated inflammation in SCI, which may be attributable to its inhibition of the TLR4/NF-κB pathway.

Brain alarm by self-extracellular nucleic acids: from neuroinflammation to neurodegeneration

Neurological disorders such as stroke, multiple sclerosis, as well as the neurodegenerative diseases Parkinson's or Alzheimer's disease are accompanied or even powered by danger associated molecular patterns (DAMPs), defined as endogenous molecules released from stressed or damaged tissue. Besides protein-related DAMPs or "alarmins", numerous nucleic acid DAMPs exist in body fluids, such as cell-free nuclear and mitochondrial DNA as well as different species of extracellular RNA, collectively termed as self-extracellular nucleic acids (SENAs). Among these, microRNA, long non-coding RNAs, circular RNAs and extracellular ribosomal RNA constitute the majority of RNA-based DAMPs. Upon tissue injury, necrosis or apoptosis, such SENAs are released from neuronal, immune and other cells predominantly in association with extracellular vesicles and may be translocated to target cells where they can induce intracellular regulatory pathways in gene transcription and translation. The majority of SENA-induced signaling reactions in the brain appear to be related to neuroinflammatory processes, often causally associated with the onset or progression of the respective disease. In this review, the impact of the diverse types of SENAs on neuroinflammatory and neurodegenerative diseases will be discussed. Based on the accumulating knowledge in this field, several specific antagonistic approaches are presented that could serve as therapeutic interventions to lower the pathological outcome of the indicated brain disorders.

MiR-181c-5p ameliorates learning and memory in sleep-deprived mice via HMGB1/TLR4/NF-κB pathway

Sleep deprivation (SD) can lead to cognitive impairment caused by neuroinflammation. MiR-181c-5p/HMGB1 axis plays a part in anti-inflammation effects. However, the mechanism that miR-181c-5p facilitates learning and memory in SD mice remains unclear. So we investigated the role of miR-181c-5p in learning and memory impairment induced by SD. We overexpressed miR-181c-5p in the mice hippocampus by injecting lentivirus vector-miR-181c-5p (LV-miR-181c-5p) particles. Mice were divided into four groups: control (Ctrl), SD, SD + miR-181c-5p and SD + vector. We found that mice in the third group showed ameliorated learning and memory compared with the fourth group. The content of ionized calcium binding adaptor molecule 1 (IBA-1) in the third group was decreased compared with the fourth group. Moreover, the expression levels of HMGB1, TLR4 and p-NF-κB in the hippocampus of overexpressed miR-181c-5p mice were reduced. In total, miR-181c-5p ameliorated learning and memory in SD mice via the HMGB1/TLR4/NF-κB pathway.

Dysregulation of Serum MicroRNA after Intracerebral Hemorrhage in Aged Mice

Stroke is one of the most common diseases that leads to brain injury and mortality in patients, and intracerebral hemorrhage (ICH) is the most devastating subtype of stroke. Though the prevalence of ICH increases with aging, the effect of aging on the pathophysiology of ICH remains largely understudied. Moreover, there is no effective treatment for ICH. Recent studies have demonstrated the potential of circulating microRNAs as non-invasive diagnostic and prognostic biomarkers in various pathological conditions. While many studies have identified microRNAs that play roles in the pathophysiology of brain injury, few demonstrated their functions and roles after ICH. Given this significant knowledge gap, the present study aims to identify microRNAs that could serve as potential biomarkers of ICH in the elderly. To this end, sham or ICH was induced in aged C57BL/6 mice (18–24 months), and 24 h post-ICH, serum microRNAs were isolated, and expressions were analyzed. We identified 28 significantly dysregulated microRNAs between ICH and sham groups, suggesting their potential to serve as blood biomarkers of acute ICH. Among those microRNAs, based on the current literature, miR-124-3p, miR-137-5p, miR-138-5p, miR-219a-2-3p, miR-135a-5p, miR-541-5p, and miR-770-3p may serve as the most promising blood biomarker candidates of ICH, warranting further investigation.

Recent Advances in the Roles of MicroRNA and MicroRNA-Based Diagnosis in Neurodegenerative Diseases

Neurodegenerative diseases manifest as progressive loss of neuronal structures and their myelin sheaths and lead to substantial morbidity and mortality, especially in the elderly. Despite extensive research, there are few effective treatment options for the diseases. MicroRNAs have been shown to be involved in the developmental processes of the central nervous system. Mounting evidence suggest they play an important role in the development of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. However, there are few reviews regarding the roles of miRNAs in neurodegenerative diseases. This review summarizes the recent developments in the roles of microRNAs in neurodegenerative diseases and presents the application of microRNA-based methods in the early diagnosis of these diseases.

Potential of nobiletin against Alzheimer's disease through inhibiting neuroinflammation

OBJECTIVE

This study aimed to explore the mechanism of Nobiletin attenuating Alzheimer's disease (AD) by inhibiting neuroinflammation.

METHODS

The expression of inflammatory cytokines and HMGB-1 in serum of AD patients were examined. Microglia (MGs) were treated with different doses of Nobiletin before LPS and Nigericin induction. Cell viability and apoptosis were determined by CCK-8 and TUNEL assays, respectively. APP/PS1 mice were gavaged with Nobiletin, and Morris water maze (MWM) was established to record swimming speed, escape latency, the number of platform crossings, and time spent in the platform quadrant. MGs activation in brain tissues was evaluated by immunofluorescence. The expression of pyroptosis-related proteins, inflammatory cytokines, and HMGB-1 was determined in the hippocampus and MGs.

RESULTS

The levels of inflammatory cytokines and HMGB-1 were high in serum of AD patients. Treatment with different concentrations of Nobiletin prominently enhanced cell viability and reduced apoptosis and the expression of inflammatory cytokine and pyroptosis-related proteins in LPS + Nigericin-induced MGs. Gavage of different doses of Nobiletin into APP/PS1 mice shortened the escape latency in mice, diminished MGs activation in brain tissues, and remarkably elevated the number of platform crossings and the time spent in the platform quadrant without obvious change in swimming speed, suggesting that Nobiletin improved the spatial learning and memory abilities in APP/PS1 mice. The expression of pyroptosis-related proteins, HMGB-1, and inflammatory cytokines was decreased dramatically by Nobiletin in the hippocampus of APP/PS1 mice.

CONCLUSIONS

Nobiletin can inhibit neuroinflammation by inhibiting HMGB-1, pyroptosis-related proteins, and inflammatory cytokines, thus mitigating AD.

Glycyrrhizic Acid Attenuates the Inflammatory Response After Spinal Cord Injury by Inhibiting High Mobility Group Box-1 Protein Through the p38/Jun N-Terminal Kinase Signaling Pathway

BACKGROUND

Neuroinflammation is an important secondary aggravating factor in spinal cord injury (SCI). Inhibition of the inflammatory response is critical for SCI treatment. Glycyrrhizic acid (GA) is an anti-inflammatory drug, but its utility for SCI is unclear. This study aimed to evaluate the effects of GA on inflammation after SCI and the underlying mechanism.

METHODS

Cell counting kit-8 assays were performed to assess the viability of highly aggressively proliferating immortalized cells that had been treated with lipopolysaccharide (LPS) and/or GA. Reverse transcription quantitative polymerase chain reaction and Western blotting were performed to assess expression of high mobility group box-1 protein (HMGB1), ionized calcium binding adaptor molecule 1, and inflammatory factors in vitro and in vivo. GA (100 mg/kg) was intraperitoneally injected into rats. Anti-inflammatory effects of GA were analyzed in SCI tissues. p38/Jun N-terminal kinase signaling pathway proteins were analyzed by Western blotting.

RESULTS

Cell counting kit-8 assay results showed that treatment with 100 ng/mL LPS for 12 hours was optimal. After LPS treatment, highly aggressively proliferating immortalized cells were activated; messenger RNA expression levels of HMGB1 and inflammatory factors were increased. GA significantly inhibited LPS-induced HMGB1 expression and inflammatory responses, as determined by reverse transcription quantitative polymerase chain reaction and Western blotting. Transfection with an HMGB1-overexpression plasmid reversed the anti-inflammatory effects of GA. In addition, intraperitoneal injection of GA (100 mg/kg) into rats for 3 days significantly reduced expression levels of HMGB1 and inflammatory factors after SCI in vivo. GA reduced phosphorylation, but not levels, of p38 and Jun N-terminal kinase proteins.

CONCLUSIONS

GA attenuates the inflammatory response after SCI by inhibiting HMGB1 through the p38/JNK signaling pathway and thus has therapeutic potential for SCI.