MicroRNAs as Peripheral Biomarkers in Aging and Age-Related Diseases

The role of peripheral blood microRNAs in the pathogenesis and treatment response of age-related macular degeneration

Age-related macular degeneration is a leading cause of vision loss in aging populations, driven by complex interactions between genetic, environmental, and molecular factors. MicroRNAs have emerged as crucial regulators of cellular processes such as oxidative stress, inflammation, and angiogenesis, all of which contribute to AMD pathogenesis. This narrative review aims to summarize the involvement of peripheral blood microRNAs in the pathogenesis of AMD, focusing on key pathways such as oxidative stress, inflammation, and angiogenesis. Additionally, it explores their potential as biomarkers for predicting treatment response, particularly to anti-VEGF therapies. The potential of miRNAs as noninvasive biomarkers for early diagnosis and personalized treatment strategies is also explored, highlighting future directions for research.

Exploring Exosome-Based Approaches for Early Diagnosis and Treatment of Neurodegenerative Diseases

Neurodegenerative diseases (NDs), like Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and Amyotrophic Lateral Sclerosis (ALS), present an increasingly significant global health burden, primarily due to the lack of effective early diagnostic tools and treatments. Exosomes-nano-sized extracellular vesicles secreted by nearly all cell types-have emerged as promising candidates for both biomarkers and therapeutic agents in NDs. This review examines the biogenesis, molecular composition, and diverse functions of exosomes in NDs. Exosomes play a crucial role in mediating intercellular communication. They are capable of reflecting the biochemical state of their parent cells and have the ability to cross the blood-brain barrier (BBB). In doing so, they facilitate the propagation of pathological proteins, such as amyloid-beta (Aβ), tau, and alpha-synuclein (α-syn), while also enabling the targeted delivery of neuroprotective compounds. Recent advancements in exosome isolation and engineering have opened up new possibilities for diagnostic and therapeutic strategies. These range from the discovery of non-invasive biomarkers to innovative approaches in gene therapy and drug delivery systems. However, challenges related to standardization, safety, and long-term effects must be addressed before exosomes can be translated into clinical applications. This review highlights both the promising potential and the obstacles that must be overcome to leverage exosomes in the treatment of NDs and the transformation of personalized medicine.

The Hsa_circ_0105558/miR-182-5p/ATF6 Cascade Affects H2O2-Triggered Oxidative Damage and Apoptosis of Human Lens Epithelial Cells

Age-related cataract (ARC) is the prevalent cause of useful vision loss. Circular RNAs are related to ARC pathogenesis partly through their competing endogenous RNA (ceRNA) activity. Herein, we defined the action of hsa_circ_0105558 in hydrogen peroxide (H2O2)-driven apoptosis and oxidative damage in human lens epithelial SRA01/04 cells. Hsa_circ_0105558, microRNA (miR)-182-5p and activating transcription factor 6 (ATF6) were evaluated by a qRT-PCR or immunoblotting method. The hsa_circ_0105558/miR-182-5p and miR-182-5p/ATF6 relationships were predicted by bioinformatics analysis and confirmed by dual-luciferase reporter assay. Reactive oxygen species level, glutathione peroxidase level, superoxide dismutase activity, and malondialdehyde level were measured using the matched assay kits. Hsa_circ_0105558 was upregulated in human ARC lens and H2O2-exposed SRA01/04 cells. Suppression of hsa_circ_0105558 attenuated H2O2-driven SRA01/04 cell apoptosis and oxidative damage. Hsa_circ_0105558 targeted miR-182-5p, and reduced miR-182-5p expression reversed the influence of hsa_circ_0105558 depletion on H2O2-driven oxidative damage and apoptosis. ATF6 was a target of miR-182-5p, and miR-182-5p-driven downregulation of ATF6 regulated cell oxidative damage and apoptosis under H2O2 insult. Moreover, hsa_circ_0105558 functioned as a ceRNA to post-transcriptionally control ATF6 expression through miR-182-5p competition. Our study demonstrates that hsa_circ_0105558 modulates SRA01/04 cell oxidative damage and apoptosis under H2O2 insult through the miR-182-5p/ATF6 cascade.

Effects of Clinical Covariates on Serum miRNA Expression among Women without Ovarian Cancer

BACKGROUND

Serum miRNAs are potential biomarkers for ovarian cancer; however, many factors may influence miRNA expression. To understand potential confounders in miRNA analysis, we examined how sociodemographic factors and comorbidities, including known ovarian cancer risk factors, influence serum miRNA levels in women without ovarian cancer.

METHODS

Data from 1,576 women from the Mass General Brigham Biobank collected between 2012 and 2019, excluding subjects previously or subsequently diagnosed with ovarian cancer, were examined. Using a focused panel of 179 miRNA probes optimized for serum profiling, miRNA expression was measured by flow cytometry using the Abcam FirePlex assay and correlated with subjects' electronic medical records.

RESULTS

The study population broadly reflected the New England population. The median age of subjects was 49 years, 34% were current or prior smokers, 33% were obese (body mass index > 30 kg/m2), 49% were postmenopausal, and 11% had undergone prior bilateral oophorectomy. Significant differences in miRNA expression were observed among ovarian risk factors such as age, obesity, menopause, BRCA1 or BRCA2 germline mutations, or existence of breast cancer in family history. Additionally, miRNA expression was significantly altered by prior bilateral oophorectomy, hypertension, and hypercholesterolemia. Other variables, such as smoking; parity; age at menarche; hormonal replacement therapy; oral contraception; breast, endometrial, or colon cancer; and diabetes, were not associated with significant changes in the panel when corrected for multiple testing.

CONCLUSIONS

Serum miRNA expression patterns are significantly affected by patient demographics, exposure history, and medical comorbidities.

IMPACT

Understanding confounders in serum miRNA expression is important for refining clinical assays for cancer screening.

What Is the Impact of Obesity-Related Comorbidities on the Risk of Premature Aging in Patients with Severe Obesity?: A Cross-Sectional Study

Background and Objectives: The relationships between aging, chronic diseases, and obesity remain complex and poorly understood. This study aimed to investigate the impact of comorbidities on premature aging in individuals with severe obesity. Materials and Methods: This cross-sectional study included 99 bariatric patients with severe obesity (SG) and 30 healthy volunteers (HC). SG was further divided into subgroups based on comorbidity status. Various markers of biological aging, including interleukin-6 (IL-6), C-reactive protein (CRP), telomere length (TL), attention speed, executive functions, and metabolic age, were evaluated. Results: Both subgroups of patients with obesity presented elevated levels of IL-6 and CRP, shorter TLs, lower outcomes in executive functioning tests, and greater metabolic age than healthy subjects. However, no significant differences were observed between patients with obesity with and without comorbidities. This study highlighted the impact of BMI on increased inflammation and revealed that hypertension and inflammation are associated with cognitive decline. Conclusions: These findings suggest that obesity, regardless of comorbidities, contributes to premature aging. The presence of hypertension was linked to cognitive function decline, emphasizing the multifaceted implications of obesity for the aging process.

A review on gut microbiota and miRNA crosstalk: implications for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and progressive neuronal damage. Recent research has highlighted the significant roles of the gut microbiota and microRNAs (miRNAs) in the pathogenesis of AD. This review explores the intricate interaction between gut microbiota and miRNAs, emphasizing their combined impact on Alzheimer's progression. First, we discuss the bidirectional communication within the gut-brain axis and how gut dysbiosis contributes to neuroinflammation and neurodegeneration in AD. Changes in gut microbiota composition in Alzheimer's patients have been linked to inflammation, which exacerbates disease progression. Next, we delve into the biology of miRNAs, focusing on their roles in gene regulation, neurodevelopment, and neurodegeneration. Dysregulated miRNAs are implicated in AD pathogenesis, influencing key processes like inflammation, tau pathology, and amyloid deposition. We then examine how the gut microbiota modulates miRNA expression, particularly in the brain, potentially altering neuroinflammatory responses and synaptic plasticity. The interplay between gut microbiota and miRNAs also affects blood-brain barrier integrity, further contributing to Alzheimer's pathology. Lastly, we explore therapeutic strategies targeting this gut microbiota-miRNA axis, including probiotics, prebiotics, and dietary interventions, aiming to modulate miRNA expression and improve AD outcomes. While promising, challenges remain in fully elucidating these interactions and translating them into effective therapies. This review highlights the importance of understanding the gut microbiota-miRNA relationship in AD, offering potential pathways for novel therapeutic approaches aimed at mitigating the disease's progression.

MiRNA-501-3p and MiRNA-502-3p: A Promising Biomarker Panel for Alzheimer's Disease

INTRODUCTION

Alzheimer's disease (AD) lacks a less invasive and early detectable biomarker. Here, we investigated the biomarker potential of miR-501-3p and miR-502-3p using different AD sources.

METHODS

MiR-501-3p and miR-502-3p expressions were evaluated in AD CSF exosomes, serum exosomes, familial and sporadic AD fibroblasts and B-lymphocytes by qRT-PCR analysis. Further, miR-501-3p and miR-502-3p expressions were analyzed in APP, Tau cells and media exosomes.

RESULTS

MiR-501-3p and miR-502-3p expressions were significantly upregulated in AD CSF exosomes relative to controls. MiRNA levels were high in accordance with amyloid plaque and NFT density in multiple brain regions. Similarly, both miRNAs were elevated in AD and MCI serum exosomes compared to controls. MiR-502-3p expression was high in fAD and sAD B-lymphocytes. Finally, miR-501-3p and miR-502-3p expression were elevated intracellularly and secreted extracellularly in response to APP and Tau pathology.

DISCUSSION

These results suggest that miR-501-3p and miR-502-3p could be promising biomarkers for AD.

MicroRNA-502-3p modulates the GABA A subunits, synaptic proteins and mitochondrial morphology in hippocampal neurons

MicroRNA-502-3p (MiR-502-3p), a synapse enriched miRNA is considerably implicated in Alzheimer's disease (AD). Our previous study found the high expression level of miR-502-3p in AD synapses relative to controls. Further, miR-502-3p was found to modulate the GABAergic synapse function via modulating the GABA A receptor subunit α-1 (GABRA1) protein. The current study is attempted to examine the impact of miR-502-3p on other GABA subunit proteins, synaptic proteins, mitochondrial morphology and other hippocampal neuron genes. Mouse hippocampal neuronal (HT22) cells were transfected with miR-502-3p overexpression (OE) vector, miR-502-3p sponge (suppression) vector and scramble control vector. MiR-502-3p vectors transfection was confirmed by fluorescence microscopy. MiR-502-3p expression and GABRA1 expression was confirmed by qRT-PCR and miRNAScope in-situ hybridization. GABA A subunit and synaptic proteins were studied by immunoblotting analysis and mitochondrial morphology was analyzed by transmission electron microscopy (TEM) analysis. Further, Affymetrix gene array analysis was conducted in miR-502-3p overexpressed and suppressed cells. Our results observed that elevated miR-502-3p, negatively modulates the GABRA1 level. The levels of GABA A subunit and synaptic proteins were reduced by ectopic expression of miR-502-3p and increase by miR-502-3p suppression. The mitochondrial morphology was found to be improved in-terms of their number and length in miR-502-3p suppressed cells. Further, Gene array analysis unveiled the deregulation of several genes by miR-502-3p, which are associated with oxidative stress, immune response and synaptic function. These results provide new insights and an update to understand the biological roles of miR-502-3p in regulation of neuron function and synaptic activity.

Integrated Multi-Omics Analyses of Synaptosomes Revealed Synapse-Centered Novel Targets in Alzheimer's Disease

Synapse dysfunction is an early event in Alzheimer's disease (AD) caused by various factors such as Amyloid beta, p-tau, inflammation, and aging. However, the exact molecular mechanism of synapse dysfunction in AD is largely unknown. To understand this, we comprehensively analyzed the synaptosome fraction in postmortem brain samples from AD patients and cognitively normal individuals. We conducted high-throughput transcriptomic analyses to identify changes in microRNA (miRNA) and mRNA levels in synaptosomes extracted from the brains of both unaffected individuals and those with Alzheimer's disease (AD). Additionally, we performed mass spectrometry analysis of synaptosomal proteins in the same sample group. These analyses revealed significant differences in the levels of miRNAs, mRNAs, and proteins between the groups. To further understand the pathways or molecules involved, we used an integrated omics approach and studied the molecular interactions of deregulated synapse miRNAs, mRNAs, and proteins in the samples from individuals with AD and the control group, which demonstrated the impact of deregulated miRNAs on their target mRNAs and proteins. Furthermore, the DIABLO analysis highlighted complex relationships between mRNAs, miRNAs, and proteins that could be key in understanding the pathophysiology of AD. Our study identified synapse-centered novel candidates that could be critical in restoring synapse dysfunction in AD.

Effects of MicroRNAs and Long Non-coding RNAs on Beneficial Action of Exercise on Cognition in Degenerative Diseases: A Review

Recent research has exposed a growing body of proof underscoring the importance of microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) in maintaining the physical composition of neurons and influencing cognitive functioning in both standard and atypical circumstances. Extensive research has been conducted on the possible application of miRNAs and lncRNAs as biomarkers for various diseases, with a particular focus on brain disorders, as they possess remarkable durability in cell-free surroundings and can endure repeated freezing and thawing processes. It is intriguing to note that miRNAs and lncRNAs have the ability to function through paracrine mechanisms, thereby playing a role in communication between different organs. Recent research has proposed that the improvement of cognitive abilities through physical exercise in mentally healthy individuals is a valuable method for uncovering potential connections between miRNAs, or microRNAs, and lncRNAs, and human cognitive function. The process of cross-correlating data from disease models and patients with existing data will be crucial in identifying essential miRNAs and lncRNAs, which can potentially act as biomarkers or drug targets in the treatment of cognitive disorders. By combining this method with additional research in animal models, we can determine the function of these molecules and their potential impact on therapy. This article discusses the latest research about the primary miRNAs, lncRNAs, and their exosomes that are affected by physical activity in terms of human cognitive function.

Identification of differentially expressed miRNAs involved in vascular aging reveals pathways associated with the endocrine hormone regulation

Vascular aging refers to a series of processes where the elasticity of blood vessels diminishes, leading to stiffening, and deposition of fat components on the vessel walls, causing inflammation. Cardiovascular diseases, such as stroke and hypertension, play significant roles in morbidity and mortality rates among the elderly population. In this study, the Reactive Hyperemia Index (RHI) was measured to assess vascular endothelial function and aging-induced pathogenesis of vascular diseases in Korean subjects. We aimed to identify extracellular vesicle microRNAs (EV-miRNAs) with differential abundance between groups of individuals at the ends of a continuum in vascular aging acceleration, revealing miRNAs regulating genes in endocrine hormone regulation and tumor-related pathways. We also discovered that the principal component characterizing the global miRNA expression profile is significantly associated with clinical traits including cholesterol levels. Together, these data provide a foundation for understanding the role of miRNAs as modulators of longevity and for developing age-specific epigenetic biomarkers.

Engineering extracellular vesicles to transiently permeabilize the blood-brain barrier

BACKGROUND

Drug delivery to the brain is challenging due to the restrict permeability of the blood brain barrier (BBB). Recent studies indicate that BBB permeability increases over time during physiological aging likely due to factors (including extracellular vesicles (EVs)) that exist in the bloodstream. Therefore, inspiration can be taken from aging to develop new strategies for the transient opening of the BBB for drug delivery to the brain.

RESULTS

Here, we evaluated the impact of small EVs (sEVs) enriched with microRNAs (miRNAs) overexpressed during aging, with the capacity to interfere transiently with the BBB. Initially, we investigated whether the miRNAs were overexpressed in sEVs collected from plasma of aged individuals. Next, we evaluated the opening properties of the miRNA-enriched sEVs in a static or dynamic (under flow) human in vitro BBB model. Our results showed that miR-383-3p-enriched sEVs significantly increased BBB permeability in a reversible manner by decreasing the expression of claudin 5, an important tight junction protein of brain endothelial cells (BECs) of the BBB, mediated in part by the knockdown of activating transcription factor 4 (ATF4).

CONCLUSIONS

Our findings suggest that engineered sEVs have potential as a strategy for the temporary BBB opening, making it easier for drugs to reach the brain when injected into the bloodstream.

A Comprehensive Review of Membrane Transporters and MicroRNA Regulation in Alzheimer's Disease

Alzheimer's disease (AD) is a distressing neurodegenerative condition characterized by the accumulation of amyloid-beta (Aβ) plaques and tau tangles within the brain. The interconnectedness between membrane transporters (SLCs) and microRNAs (miRNAs) in AD pathogenesis has gained increasing attention. This review explores the localization, substrates, and functions of SLC transporters in the brain, emphasizing the roles of transporters for glutamate, glucose, nucleosides, and other essential compounds. The examination delves into the significance of SLCs in AD, their potential for drug development, and the intricate realm of miRNAs, encompassing their transcription, processing, functions, and regulation. MiRNAs have emerged as significant players in AD, including those associated with mitochondria and synapses. Furthermore, this review discusses the intriguing nexus of miRNAs targeting SLC transporters and their potential as therapeutic targets in AD. Finally, the review underscores the interaction between SLC transporters and miRNA regulation within the context of Alzheimer's disease, underscoring the need for further research in this area. This comprehensive review aims to shed light on the complex mechanisms underlying the causation of AD and provides insights into potential therapeutic approaches.

MicroRNA-455-3P as a peripheral biomarker and therapeutic target for mild cognitive impairment and Alzheimer's disease

MicroRNAs are small non-coding RNAs evolutionary conserved molecules. They regulate cellular processes, including RNA silencing, post-translational gene expression and neurodegeneration. MicroRNAs are involved with human diseases such as cancer, Alzheimer's disease (AD) and others. Interestingly, cerebrospinal fluids (CSF) and the blood of AD patients have altered expressions of many RNAs, which may serve as potential peripheral biomarkers. The intensive investigation from our lab revealed that microRNA-455-3 P (miR-455-3p) is a strong candidate as a potential biomarker and therapeutic target for AD. Several genes implicated in the pathogenesis of AD are directly targeted by miR-455-3p. Several years of our lab research revealed that miR-455-3p regulates important physiological processes associated with AD, such as the processing of the amyloid precursor protein (APP), TGF-β signaling, the regulation of oxidative stress, mitochondrial biogenesis, and synaptic damages. The expression of miR-455-3p in mild cognitive impaired subjects and AD patients pointed out its involvement in AD progression. Recently, our lab generated both transgenic and knockout mice for miR-455-3p. Interestingly miR-455-3p transgenic mice showed superior cognitive learning, improved memory and extended lifespan compared to age matched wild-type mice, whereas miR-455-3-p knockout mice showed cognitive decline and reduced lifespan. Information derived from mouse models further demonstrated the advantageous impact of miR-455-3p on dendritic growth, synaptogenesis, and mitochondrial biogenesis in preventing the onset and progression of AD. The identification of miR-455-3p as a biomarker was suggested by its presence in postmortem AD brains, B-lymphocytes, and fibroblasts. Our hypothesis that miR-455-3p could be a peripheral biomarker and therapeutic target for AD.

Epigenetic biomarkers in aging and longevity: Current and future application

The aging process has been one of the most necessary research fields in the current century, and knowing different theories of aging and the role of different genetic, epigenetic, molecular, and environmental modulating factors in increasing the knowledge of aging mechanisms and developing appropriate diagnostic, therapeutic, and preventive ways would be helpful. One of the most conserved signs of aging is epigenetic changes, including DNA methylation, histone modifications, chromatin remodeling, noncoding RNAs, and extracellular RNAs. Numerous biological processes and hallmarks are vital in aging development, but epigenomic alterations are especially notable because of their importance in gene regulation and cellular identity. The mounting evidence points to a possible interaction between age-related epigenomic alterations and other aging hallmarks, like genome instability. To extend a healthy lifespan and possibly reverse some facets of aging and aging-related diseases, it will be crucial to comprehend global and locus-specific epigenomic modifications and recognize corresponding regulators of health and longevity. In the current study, we will aim to discuss the role of epigenomic mechanisms in aging and the most recent developments in epigenetic diagnostic biomarkers, which have the potential to focus efforts on reversing the destructive signs of aging and extending the lifespan.

Machine and deep learning algorithms for classifying different types of dementia: A literature review

The cognitive impairment known as dementia affects millions of individuals throughout the globe. The use of machine learning (ML) and deep learning (DL) algorithms has shown great promise as a means of early identification and treatment of dementia. Dementias such as Alzheimer's Dementia, frontotemporal dementia, Lewy body dementia, and vascular dementia are all discussed in this article, along with a literature review on using ML algorithms in their diagnosis. Different ML algorithms, such as support vector machines, artificial neural networks, decision trees, and random forests, are compared and contrasted, along with their benefits and drawbacks. As discussed in this article, accurate ML models may be achieved by carefully considering feature selection and data preparation. We also discuss how ML algorithms can predict disease progression and patient responses to therapy. However, overreliance on ML and DL technologies should be avoided without further proof. It's important to note that these technologies are meant to assist in diagnosis but should not be used as the sole criteria for a final diagnosis. The research implies that ML algorithms may help increase the precision with which dementia is diagnosed, especially in its early stages. The efficacy of ML and DL algorithms in clinical contexts must be verified, and ethical issues around the use of personal data must be addressed, but this requires more study.

Unveiling the role of exosomes as cellular messengers in neurodegenerative diseases and their potential therapeutic implications

Exosomes are a subgroup of extracellular vesicles that function as transmitters, allowing cells to communicate more effectively with each other. However, exosomes may have both beneficial and harmful impacts on central nervous system disorders. Hence, the fundamental molecular mechanisms of the origin of illness and its progression are currently being investigated. The involvement of exosomes in the origin and propagation of neurodegenerative illness has been demonstrated recently. Exosomes provide a representation of the intracellular environment since they include various essential bioactive chemicals. The latest studies have demonstrated that exosomes transport several proteins. Additionally, these physiological vesicles are important in the regeneration of nervous tissue and the healing of neuronal lesions. They also offer a microenvironment to stimulate the conformational variation of concerning proteins for aggregation, resulting in neurodegenerative diseases. The biosynthesis, composition, and significance of exosomes as extracellular biomarkers in neurodegenerative disorders are discussed in this article, with a particular emphasis on their neuroprotective effects.

MiR-34a-HK1 signal axis retards bone marrow mesenchymal stem cell senescence via ameliorating glycolytic metabolism

BACKGROUND

Mesenchymal stem cells (MSCs) are one of the most widely studied adult stem cells, while MSC replicative senescence occurs with serial expansion in vitro. We determined whether miR-34a can regulate MSC senescence by directly targeting glycolytic key enzymes to influence glycolysis.

METHODS

Detected the effects of miR-34a on MSC senescence and glycolytic metabolism through gene manipulation. Bioinformatics prediction and luciferase reporter assay were applied to confirm that HK1 is a direct target of miR-34a. The underlying regulatory mechanism of miR-34a targeting HK1 in MSC senescence was further explored by a cellular function recovery experiment.

RESULTS

In the current study, we revealed that miR-34a over-expression exacerbated senescence-associated characteristics and impaired glycolytic metabolism. Then we identified hexokinase1 (HK1) as a direct target gene of miR-34a. And HK1 replenishment reversed MSC senescence and reinforced glycolysis. In addition, miR-34a-mediated MSC senescence and lower glycolytic levels were evidently rescued following the co-treatment with HK1 over-expression.

CONCLUSION

The miR-34a-HK1 signal axis can alleviate MSC senescence via enhancing glycolytic metabolism, which possibly provides a novel mechanism for MSC senescence and opens up new possibilities for delaying and suppressing the occurrence and development of aging and age-related diseases.

miRNA-142-3p aggravates hydrogen peroxide-induced human umbilical vein endothelial cell premature senescence by targeting SIRT1

Vascular endothelial cell premature senescence plays an important part in stroke. Many microRNAs (miRNAs) are known to be involved in the pathological process of vascular endothelial cell premature senescence. The present study aimed to investigate the mechanism of hydrogen peroxide (H2O2)-induced premature senescence in human umbilical vein endothelial cells (HUVECs) and effect of miR-142-3p on hydrogen peroxide (H2O2)-induced premature senescence. HUVECs were exposed to H2O2 to establish a model premature senescence in endothelial cells. CCK-8 assay was performed to detect cell viability. Senescence-associated β-galactosidase staining assay and senescence-related proteins p16 and p21 were used to detect changes in the degree of cell senescence. RT-qPCR and Western blot were conducted to measure mRNA and protein levels, respectively. The scratch wound-healing assay, transwell assay, and EdU assay were performed to evaluate the ability of migration and proliferation, respectively. miRNA-142-3p and silencing information regulator 2 related enzyme 1 (SIRT1) binding was verified using Targetscan software and a dual-luciferase assay. We found that miRNA-142-3p is abnormally up-regulated in HUVECs treated with H2O2. Functionally, miRNA-142-3p inhibition may mitigate the degree of HUVEC senescence and improve HUVEC migration and proliferation. Mechanistically, SIRT1 was validated to be targeted by miRNA-142-3p in HUVECs. Moreover, SIRT1 inhibition reversed the effects of miRNA-142-3p inhibition on senescent HUVECs exposed to H2O2. To our knowledge, this is the first study to show that miRNA-142-3p ameliorates H2O2-induced HUVECs premature senescence by targeting SIRT1 and may shed light on the role of the miR-142-3p/SIRT1 axis in stroke treatment.

CircMAP3K4 Suppresses H2O2-Induced Human Lens Epithelial Cell Injury by miR-630/ERCC6 Axis in Age-Related Cataract

BACKGROUND

Dysregulated circular RNAs (circRNAs) is involved in the pathogenesis of age-related cataract (ARC). Here, this study aimed to explore the function and mechanism of circMAP3K4 in ARC.

METHODS

Human lens epithelial cells were exposed to hydrogen peroxide (H2O2) for functional experiments. qRT-PCR and western blotting analyses were used for the expression detection of genes and proteins. Cell proliferation was tested using cell counting kit-8 and EdU. Flow cytometry was applied to analyze cell apoptosis and cell cycle. The oxidative stress was evaluated by detecting the production of malondialdehyde (MDA), reactive oxygen species (ROS), and superoxide dismutase (SOD). The target relationship between miR-630 and circMAP3K4 or Excision repair cross-complementing group 6 (ERCC6) was analyzed by dual-luciferase reporter assay and RIP assay.

RESULTS

CircMAP3K4 was lowly expressed in ARC patients and H2O2-induced HLECs. Functionally, forced expression of circMAP3K4 protected HLECs against H2O2-evoked proliferation inhibition, cell cycle arrest and the promotion of cell apoptosis and oxidative stress. Mechanistically, circMAP3K4 acted as a sponge for miR-630 to regulate the expression of its target ERCC6. MiR-630 was highly expressed while ERCC6 was lowly expressed in ARC patients and H2O2-induced HLECs. Up-regulation of miR-630 could reverse the protective effects of circMAP3K4 on HLECs under H2O2 treatment. In addition, inhibition of miR-630 suppressed H2O2-induced HLEC injury, which was abolished by ERCC6 silencing.

CONCLUSION

Forced expression of circMAP3K4 protected HLECs against H2O2-evoked apoptotic and oxidative injury via miR-630/ERCC6 axis, suggesting that circMAP3K4 may function as a potential therapeutic target for ARC.

Therapeutic effects of resveratrol on epigenetic mechanisms in age-related diseases: A comprehensive review

Recently, various studies have shown that epigenetic changes are associated with aging and age-related diseases. Both animal and human models have revealed that epigenetic processes are involved in aging mechanisms. These processes happen at multiple levels and include histone modification, DNA methylation, and changes in noncoding RNA expression. Consequently, changes in the organization of chromatin and DNA accessibility lead to the regulation of gene expression. With increasing awareness of the pivotal function of epigenetics in the aging process, researchers' attention has been drawn to how these epigenetic changes can be modified to prevent, stop, or reverse aging, senescence, and age-related diseases. Among various agents that can affect epigenetic, polyphenols are well-known phytochemicals found in fruits, vegetables, and plants. Polyphenols are found to modify epigenetic-related mechanisms in various diseases and conditions, such as metabolic disorders, obesity, neurodegenerative diseases, cancer, and cardiovascular diseases. Resveratrol (RSV) is a member of the stilbene subgroup of polyphenols which is derived from various plants, such as grapes, apples, and blueberries. Therefore, herein, we aim to summarize how RSV affects different epigenetic processes to change aging-related mechanisms. Furthermore, we discuss its roles in age-related diseases, such as Alzheimer's, Parkinson's, osteoporosis, and cardiovascular diseases.

Molecular detection of exosomal miRNAs of blood serum for prognosis of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer affecting people. The discovery of new, non-invasive, specific, and sensitive molecular biomarkers for CRC may assist in the diagnosis and support therapeutic decision making. Exosomal miRNAs have been demonstrated in carcinogenesis and CRC development, which makes these miRNAs strong biomarkers for CRC. Deep sequencing allows a robust high-throughput informatics investigation of the types and abundance of exosomal miRNAs. Thus, exosomal miRNAs can be efficiently examined as diagnostic biomarkers for disease screening. In the present study, a number of 660 mature miRNAs were detected in patients diagnosed with CRC at different stages. Of which, 29 miRNAs were differentially expressed in CRC patients compared with healthy controls. Twenty-nine miRNAs with high abundance levels were further selected for subsequent analysis. These miRNAs were either highly up-regulated (e.g., let-7a-5p, let-7c-5p, let-7f-5p, let-7d-3p, miR-423-5p, miR-3184-5p, and miR-584) or down-regulated (e.g., miR-30a-5p, miR-99-5p, miR-150-5p, miR-26-5p and miR-204-5p). These miRNAs influence critical genes in CRC, leading to either tumor growth or suppression. Most of the reported diagnostic exosomal miRNAs were shown to be circulating in blood serum. The latter is a novel miRNA that was found in exosomal profile of blood serum. Some of the predicted target genes of highly expressed miRNAs participate in several cancer pathways, including CRC pathway. These target genes include tumor suppressor genes, oncogenes and DNA repair genes. Main focus was given to multiple critical signaling cross-talking pathways including transforming growth factor β (TGFβ) signaling pathways that are directly linked to CRC. In conclusion, we recommend further analysis in order to experimentally confirm exact relationships between selected differentially expressed miRNAs and their predicted target genes and downstream functional consequences.

Serum Exosomal miRNA-125b and miRNA-451a are Potential Diagnostic Biomarker for Alzheimer's Diseases

Aim

To explore the diagnostic value of serum-derived exosomal miRNAs and predict the roles of their target genes in Alzheimer's disease (AD) based on the expression of miRNAs in AD patients.

Methods

We determined the relative concentration of exosomal miRNAs by High-throughput Second-generation Sequencing and real-time quantitative real-time PCR.

Results

71 AD patients and 71 ND subjects were collected. The study demonstrated that hsa-miR-125b-1-3p, hsa-miR-193a-5p, hsa-miR-378a-3p, hsa-miR-378i and hsa-miR-451a are differentially expressed in the serum-derived exosomes of AD patients compared with healthy subjects. According to ROC analysis, hsa-miR-125b-1-3p has an AUC of 0.765 in the AD group compared to the healthy group with a sensitivity and specificity of 82.1-67.7%, respectively. Enrichment analysis of its target genes showed that they were related to neuroactive ligand-receptor interactions, the PI3K-Akt signaling pathway, the Hippo signaling pathway and nervous system-related pathways. And, hsa-miR-451a had an AUC of 0.728 that differentiated the AD group from the healthy group with a sensitivity and specificity of 67.9% and 72.6%, respectively. Enrichment analysis of its target genes showed a relationship with cytokine-cytokine receptor interactions and the PI3K-Akt signaling pathway.

Conclusion

The dysregulation of serum exosomal microRNAs in patients with AD may promote the diagnosis of AD. The target genes of miRNAs may be involved in the occurrence and development of AD through various pathways.

Patient-derived neuron model: Capturing age-dependent adult-onset degenerative pathology in Huntington's disease

MicroRNAs play a crucial role in directly reprogramming (converting) human fibroblasts into neurons. Specifically, miR-9/9* and miR-124 (miR-9/9*-124) display neurogenic and cell fate-switching activities when ectopically expressed in human fibroblasts by erasing fibroblast identity and inducing a pan-neuronal state. These converted neurons maintain the biological age of the starting fibroblasts and thus provide a human neuron-based platform to study cellular properties in aged neurons and model adult-onset neurodegenerative disorders using patient-derived cells. Furthermore, the expression of striatal-enriched transcription factors in conjunction with miR-9/9*-124 guides the identity of medium spiny neurons (MSNs), the primary targets in Huntington's disease (HD). Converted MSNs from HD patient-derived fibroblasts (HD-MSNs) can replicate HD-related phenotypes including neurodegeneration associated with age-related declines in critical cellular functions such as autophagy. Here, we review the role of microRNAs in the direct conversion of patient-derived fibroblasts into MSNs and the practical application of converted HD-MSNs as a model for studying adult-onset neuropathology in HD. We provide valuable insights into age-related, cell-intrinsic changes contributing to neurodegeneration in HD-MSNs. Ultimately, we address a comprehensive understanding of the complex molecular landscape underlying HD pathology, offering potential avenues for therapeutic application.

Decreased plasma miR-140-3p is associated with coronary artery disease

Background

Although many circulating miRNAs (c-miRNAs) are associated with coronary artery disease (CAD), they are far from being the biomarker for CAD diagnosis or risk prediction. Therefore, novel c-miRNAs discovery and validation are still required, especially evaluating their prediction capacity.

Objectives

Identify novel CAD-related c-miRNAs and evaluate its risk prediction capacity for CAD. Methods: miRNAs associated with CAD were preliminarily investigated in three paired samples representing pre-CAD stage and CAD stage of three female individuals using the Applied Biosystems miRNA TaqMan® Low-Density Array (TLDA). Then, the candidate miRNAs were further verified in an independent case-control study including 129 CAD patients and 76 controls, and their potential practical value in prediction for CAD was evaluated using a machine learning (ML) algorithm. The accuracy of classification and prediction was assessed with the area under the receiver operating characteristic curve (AUC).

Results

TLDA analysis shows that miR-140-3p decreased significantly in CAD-stage (FC = -3.01, P = 0.007). Further study shows that miR-140-3p was significantly lower in CAD group [1.26 (0.68, 2.01)] than in control group [2.07 (1.19, 3.21)] (P < 0.001) and independently associated with CAD (P < 0.001). The addition of miR-140-3p to the variables including smoking history, HDL-c, and APOA1 improved the accuracy of classification by logistic regression and of prediction for CAD by ML models. The ML models built with miR-140-3p and HDL-c, respectively, had a similar prediction accuracy. The feature importance of miR-140-3p and HDL-c in the ML models was also similar. Decision curve analysis showed that miR-140-3p and HDL-c had almost identical net benefits.

Conclusion

Reduced levels of miR-140-3p is linked to CAD, and it is possible to use the plasma level of miR-140-3p as a means of evaluating the risk of CAD.

Analysis of the longitudinal stability of human plasma miRNAs and implications for disease biomarkers

There is great interest in developing clinical biomarker assays that can aid in non-invasive diagnosis and/or monitoring of human diseases, such as cancer, cardiovascular disease, and neurological diseases. Yet little is known about the longitudinal stability of miRNAs in human plasma. Here we assessed the intraindividual longitudinal stability of miRNAs in plasma from healthy human adults, and the impact of common factors (e.g., hemolysis, age) that may confound miRNA data. We collected blood by venipuncture biweekly over a 3-month period from 22 research participants who had fasted overnight, isolated total RNA, then performed miRNA qPCR. Filtering and normalization of the qPCR data revealed amplification of 134 miRNAs, 74 of which had high test-retest reliability and low percentage level drift, meaning they were stable in an individual over the 3-month time period. We also determined that, of nuisance factors, hemolysis and tobacco use have the greatest impact on miRNA levels and variance. These findings support that many miRNAs show intraindividual longitudinal stability in plasma from healthy human adults, including some reported as candidate biomarkers for Alzheimer's disease.

Unveiling the Role of Novel miRNA PC-5P-12969 in Alleviating Alzheimer's Disease

Background

The intricate and complex molecular mechanisms that underlie the progression of Alzheimer's disease (AD) have prompted a concerted and vigorous research endeavor aimed at uncovering potential avenues for therapeutic intervention.

Objective

This study aims to elucidate the role of miRNA PC-5P-12969 in the pathogenesis of AD.

Methods

We assessed the differential expression of miRNA PC-5P-12969 in postmortem AD brains, AD animal and cell models using real-time reverse-transcriptase RT-PCR, we also checked the gene and protein expression of GSK3α and APP.

Results

Our investigation revealed a notable upregulation of miRNA PC-5P-12969 in postmortem brains of AD patients, in transgenic mouse models of AD, and in mutant APP overexpressing-HT22 cells. Additionally, our findings indicate that overexpression of miRNA PC-5P-12969 exerts a protective effect on cell survival, while concurrently mitigating apoptotic cell death. Further-more, we established a robust and specific interaction between miRNA PC-5P-12969 and GSK3α. Our luciferase reporter assays provided confirmation of the binding between miRNA PC-5P-12969 and the 3'-UTR of the GSK3α gene. Manipulation of miRNA PC-5P-12969 levels in cellular models of AD yielded noteworthy alterations in the gene and protein expression levels of both GSK3α and APP. Remarkably, the manipulation of miRNA PC-5P-12969 levels yielded significant enhancements in mitochondrial respiration and ATP production, concurrently with a reduction in mitochondrial fragmentation, thus unveiling a potential regulatory role of miRNA PC-5P-12969 in these vital cellular processes.

Conclusions

In summary, this study sheds light on the crucial role of miRNA PC-5P-12969 and its direct interaction with GSK3α in the context of AD.

Factors affecting the GABAergic synapse function in Alzheimer's disease: Focus on microRNAs

Alzheimer's disease (AD) is a progressive neurological disease characterized by the loss of cognitive function, confusion, and memory deficit. Accumulation of abnormal proteins, amyloid beta (Aß), and phosphorylated Tau (p-tau) forms plaques and tangles that deteriorate synapse function, resulting in neurodegeneration and cognitive decline in AD. The human brain is composed of different types of neurons and/or synapses that are functionally defective in AD. The GABAergic synapse, the most abundant inhibitory neuron in the human brain was found to be dysfunctional in AD and contributes to disrupting neurological function. This study explored the types of GABA receptors associated with neurological dysfunction and various biological and environmental factors that cause GABAergic neuron dysfunction in AD, such as Aβ, p-tau, aging, sex, astrocytes, microglia, APOE, mental disorder, diet, physical activity, and sleep. Furthermore, we explored the role of microRNAs (miRNAs) in the regulation of GABAergic synapse function in neurological disorders and AD states. We also discuss the molecular mechanisms underlying GABAergic synapse dysfunction with a focus on miR-27b, miR-30a, miR-190a/b, miR-33, miR-51, miR-129-5p, miR-376-3p, miR-376c, miR-30b and miR-502-3p. The purpose of our article is to highlight the recent research on miRNAs affecting the regulation of GABAergic synapse function and factors that contribute to the progression of AD.

Potential roles of circulatory microRNAs in the onset and progression of renal and cardiac diseases: a focussed review for clinicians

The signalling mechanisms involving the kidney and heart are a niche of networks causing pathological conditions inducing inflammation, reactive oxidative species, cell apoptosis, and organ dysfunction during the onset of clinical complications. The clinical manifestation of the kidney and heart depends on various biochemical processes that influence organ dysfunction coexistence through circulatory networks, which hold utmost importance. The cells of both organs also influence remote communication, and evidence states that it may be explicitly by circulatory small noncoding RNAs, i.e. microRNAs (miRNAs). Recent developments target miRNAs as marker panels for disease diagnosis and prognosis. Circulatory miRNAs expressed in renal and cardiac disease can reveal relevant information about the niche of networks and gene transcription and regulated networks. In this review, we discuss the pertinent roles of identified circulatory miRNAs regulating signal transduction pathways critical in the onset of renal and cardiac disease, which can hold promising future targets for clinical diagnostic and prognostic purposes.

Downregulation of miR-144 blocked the proliferation and invasion of nerve cells in Hirschsprung disease by regulating Transcription Factor AP 4 (TFAP4)

BACKGROUND

Hirschsprung's disease (HSCR) is characterized by a dysfunction of enteric neural crest cells (ENCCs) proliferation, migration and premature apoptosis during embryonic development, resulting in aganglionic colon. Our aim is to explore the role of miR-144 with its target gene Transcription Factor AP 4 (TFAP4) in nerve cells in HSCR.

METHODS

The relative expression levels of miR-144 in HSCR colon samples were detected by quantitative real-time PCR (RT-qPCR). Western blot assays were conducted to investigate the TFAP4 protein expressing level. The interaction of miR-144 and TFAP4 was predicted with bioinformatics analysis and examined with luciferase reporter assays. Overexpression or knockdown of miR-144 and TFAP4 in 293T and SH-SY5Y cell lines was applied. Cell proliferation, migration and invasion were detected by CCK-8 assays, Transwell migration and invasion assays. Cell cycle and apoptosis was examined by flow cytometric analysis.

RESULTS

Downregulation of miR-144 and upregulation of TFAP4 were shown in HSCR. Luciferase reporter assay indicated that miR-144 reduced luciferase activity in 293T and SH-SY5Y transfected with TFAP4-WT-3UTR luciferase reporter and confirmed TFAP4 was the downstream target gene of miR-144. Data showed that miR-144 promoted the cell proliferation, migration and invasion of 293T and SH-SY5Y, while TFAP4 blocked the cell proliferation, migration and invasion. TFAP4 overexpression reversed the miR-144-mediated cell proliferation, migration and invasion of 293T and SH-SY5Y.

CONCLUSIONS

Downregulation of miR-144 blocked the cell proliferation and migration of nerve cells via targeting TFAP4 and contributed to the pathogenesis of HSCR. This provides an innovative and candidate target for treatment of HSCR.

The Role of miRNAs in the Development, Proliferation, and Progression of Endometrial Cancer

Endometrial cancer is one of the most common cancers in developing and developed countries. Although the detection of this cancer is high at the early stages, there is still a lack of markers to monitor the disease, its recurrence, and metastasis. MiRNAs are in charge of the post-transcriptional regulation of genes responsible for the most important biological processes, which is why they are increasingly used as biomarkers in many types of cancer. Many studies have demonstrated the influence of miRNAs on the processes related to carcinogenesis. The characteristics of miRNA expression profiles in endometrial cancer will allow their use as diagnostic and prognostic biomarkers. This paper focuses on the discussion of selected miRNAs based on the literature and their role in the development of endometrial cancer.

MiR-137 promotes TLR4/NF-κB pathway activity through targeting KDM4A, inhibits osteogenic differentiation of human bone marrow mesenchymal stem cells and aggravates osteoporosis

PURPOSE

As the global population ages rapidly, osteoporotic fractures have become an important public health problem. Previous studies have suggested that miR-137 is involved in the regulation of bone formation, but its specific regulatory mechanism remains unclear. In this study, we aimed to explore the expression, role, and regulatory mechanism of miR-137 in the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs).

METHODS

hBMSCs were induced into osteoblasts at first, and the expression level of miR-137 at different time points was detected. After knockdown and overexpression of miR-137, the effect of miR-137 on the osteogenic differentiation of hBMSCs was examined through alkaline phosphatase (ALP) staining and Alizarin Red staining. Western blotting was performed to detect the expression of runt-related transcription factor 2 (Runx2), osteocalcin (OCN), and toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway. Bioinformatics websites were used to predict the target binding sites for miR-137 and KDM4A, and the results were validated using luciferase reporter gene experiments. Moreover, the ALP activity, calcium nodule formation, and activation of Runx2, OCN, and TLR4/NF-κB pathways were observed after knockdown of KDM4A.

RESULTS

The expression of miR-137 decreased during osteogenic differentiation. Knockdown of miR-137 expression increased the osteogenic ability of hBMSCs, while overexpression of it weakened the ability. Through the activation of the TLR4/NF-κB pathway, miR-137 inhibited osteogenic differentiation. KDM4A was identified as a predicted target gene of miR-137. After knocking down KDM4A expression, the osteogenic ability of hBMSCs was diminished, and the TLR4/NF-κB pathway was activated. Furthermore, the osteogenic ability of hBMSCs was partially restored and the activation level of TLR4/NF-κB was reduced after miR-137 knockdown.

CONCLUSION

MiR-137 enhances the activity of the TLR4/NF-κB pathway by targeting KDM4A, thereby inhibiting the osteogenic differentiation of hBMSCs and exacerbating osteoporosis.

How can we modulate aging through nutrition and physical exercise? An epigenetic approach

The World Health Organization predicts that by 2050, 2.1 billion people worldwide will be over 60 years old, a drastic increase from only 1 billion in 2019. Considering these numbers, strategies to ensure an extended "healthspan" or healthy longevity are urgently needed. The present study approaches the promotion of healthspan from an epigenetic perspective. Epigenetic phenomena are modifiable in response to an individual's environmental exposures, and therefore link an individual's environment to their gene expression pattern. Epigenetic studies demonstrate that aging is associated with decondensation of the chromatin, leading to an altered heterochromatin structure, which promotes the accumulation of errors. In this review, we describe how aging impacts epigenetics and how nutrition and physical exercise can positively impact the aging process, from an epigenetic point of view. Canonical histones are replaced by histone variants, concomitant with an increase in histone post-translational modifications. A slight increase in DNA methylation at promoters has been observed, which represses transcription of previously active genes, in parallel with global genome hypomethylation. Aging is also associated with deregulation of gene expression - usually provided by non-coding RNAs - leading to both the repression of previously transcribed genes and to the transcription of previously repressed genes. Age-associated epigenetic events are less common in individuals with a healthy lifestyle, including balanced nutrition, caloric restriction and physical exercise. Healthy aging is associated with more tightly condensed chromatin, fewer PTMs and greater regulation by ncRNAs.

MicroRNAs in Age-Related Proteostasis and Stress Responses

Aging is associated with the accumulation of damaged and misfolded proteins through a decline in the protein homeostasis (proteostasis) machinery, leading to various age-associated protein misfolding diseases such as Huntington's or Parkinson's. The efficiency of cellular stress response pathways also weakens with age, further contributing to the failure to maintain proteostasis. MicroRNAs (miRNAs or miRs) are a class of small, non-coding RNAs (ncRNAs) that bind target messenger RNAs at their 3'UTR, resulting in the post-transcriptional repression of gene expression. From the discovery of aging roles for lin-4 in C. elegans, the role of numerous miRNAs in controlling the aging process has been uncovered in different organisms. Recent studies have also shown that miRNAs regulate different components of proteostasis machinery as well as cellular response pathways to proteotoxic stress, some of which are very important during aging or in age-related pathologies. Here, we present a review of these findings, highlighting the role of individual miRNAs in age-associated protein folding and degradation across different organisms. We also broadly summarize the relationships between miRNAs and organelle-specific stress response pathways during aging and in various age-associated diseases.

A Candidate microRNA Profile for Early Diagnosis of Sporadic Alzheimer’s Disease

Background: Late-onset or sporadic Alzheimer’s disease (sAD) is a neurodegenerative disease leading to cognitive impairment and memory loss. The underlying pathological changes take place several years prior to the appearance of the first clinical symptoms, however, the early diagnosis of sAD remains obscure. Objective: To identify changes in circulating microRNA (miR) expression in an effort to detect early biomarkers of underlying sAD pathology. Methods: A set of candidate miRs, earlier detected in biofluids from subjects at early stage of sAD, was linked to the proposed tau-driven adverse outcome pathway for memory loss. The relative expression of the selected miRs in serum of 12 cases (mild cognitive impairment, MCI) and 27 cognitively normal subjects, recruited within the ongoing Aiginition Longitudinal Biomarker Investigation Of Neurodegeneration (ALBION) study, was measured by RT-qPCR. Data on the protein levels of amyloid-β (Aβ42) and total/phosphorylated tau (t-tau/p-tau), in cerebrospinal fluid (CSF), and the cognitive z-scores of the participants were also retrieved. Results: Each doubling in relative expression of 13 miRs in serum changed the odds of either having MCI (versus control), or having pathological Aβ42 or pathological Aβ42 and tau (versus normal) proteins in their CSF, or was associated with the global composite z-score. Conclusion: These candidate human circulating miRs may be of great importance in early diagnosis of sAD. There is an urgent need for confirming these proposed early predictive biomarkers for sAD, contributing not only to societal but also to economic benefits.

Role of MicroRNA-502-3p in Human Diseases

MicroRNAs (miRNAs) are non-coding RNAs that play a major role in gene regulation in several diseases. MicroRNA-502-3p (MiR-502-3p) has been previously characterized in a variety of human diseases such as osteoporosis, diabetes, tuberculosis, cancers, and neurological disorders. Our studies recently explored the new role of miR-502-3p in regulating synapse function in Alzheimer’s disease (AD). AD is the most common cause of dementia in elderly individuals. Synapse is the initial target that is hit during AD progression. The most common causes of synapse dysfunction in AD are amyloid beta, hyperphosphorylated tau, and microglia activation. MiR-502-3p was found to be localized and overexpressed in the AD synapses. Overexpression of miR-502-3p was correlated with AD severity in terms of Braak stages. Studies have shown that miR-502-3p modulates the glutaminergic and GABAergic synapse function in AD. The current study’s emphasis is to discuss the in-depth roles of miR-502-3p in human diseases and AD and the future possibilities concerning miR-502-3p as a therapeutic for AD treatment.

Mitochondrial miRNA as epigenomic signatures: Visualizing aging-associated heart diseases through a new lens

Aging bears many hard knocks, but heart disorders earn a particular allusion, being the most widespread. Cardiovascular diseases (CVDs) are becoming the biggest concern to mankind due to sundry health conditions directly or indirectly related to heart-linked abnormalities. Scientists know that mitochondria play a critical role in the pathophysiology of cardiac diseases. Both environment and genetics play an essential role in modulating and controlling mitochondrial functions. Even a minor abnormality may prove detrimental to heart function. Advanced age combined with an unhealthy lifestyle can cause most cardiomyocytes to be replaced by fibrotic tissue which upsets the conducting system and leads to arrhythmias. An aging heart encounters far more heart-associated comorbidities than a young heart. Many state-of-the-art technologies and procedures are already being used to prevent and treat heart attacks worldwide. However, it remains a mystery when this heart bomb would explode because it lacks an alarm. This calls for a novel and effective strategy for timely diagnosis and a sure-fire treatment. This review article provides a comprehensive overture of prospective potentials of mitochondrial miRNAs that predict complicated and interconnected pathways concerning heart ailments and signature compilations of relevant miRNAs as biomarkers to plot the role of miRNAs in epigenomics. This article suggests that analysis of DNA methylation patterns in age-associated heart diseases may determine age-impelled biomarkers of heart disease.

Urinary Exosomes: A Promising Biomarker for Disease Diagnosis

Exosomes are nanoscale vesicles derived from endocytosis, formed by fusion of multivesicular bodies with membranes and secreted into the extracellular matrix or body fluids. Many studies have shown that exosomes can be present in a variety of biological fluids, such as plasma, urine, saliva, amniotic fluid, ascites, and sweat, and most types of cells can secrete exosomes. Exosomes play an important role in many aspects of human development, including immunity, cardiovascular diseases, neurodegenerative diseases, and neoplasia. Urine can be an alternative to blood or tissue samples as a potential source of disease biomarkers because of its simple, noninvasive, sufficient, and stable characteristics. Therefore, urinary exosomes have valuable potential for early screening, monitoring disease progression, prognosis, and treatment. The method for isolating urinary exosomes has been perfected, and exosome proteomics is widely used. Therefore, we review the potential use of urinary exosomes for disease diagnosis and summarize the related literature.

Intrahippocampal Inoculation of Aβ1-42 Peptide in Rat as a Model of Alzheimer's Disease Identified MicroRNA-146a-5p as Blood Marker with Anti-Inflammatory Function in Astrocyte Cells

Circulating microRNAs (miRNAs) have aroused a lot of interest as reliable blood diagnostic biomarkers of Alzheimer's disease (AD). Here, we investigated the panel of expressed blood miRNAs in response to aggregated Aβ_1-42 peptides infused in the hippocampus of adult rats to mimic events of the early onset of non-familial AD disorder. Aβ_1-42 peptides in the hippocampus led to cognitive impairments associated with an astrogliosis and downregulation of circulating miRNA-146a-5p, -29a-3p, -29c-3p, -125b-5p, and-191-5p. We established the kinetics of expression of selected miRNAs and found differences with those detected in the APP_swe/PS1_dE9 transgenic mouse model. Of note, miRNA-146a-5p was exclusively dysregulated in the Aβ-induced AD model. The treatment of primary astrocytes with Aβ_1-42 peptides led to miRNA-146a-5p upregulation though the activation of the NF-κB signaling pathway, which in turn downregulated IRAK-1 but not TRAF-6 expression. As a consequence, no induction of IL-1β, IL-6, or TNF-α was detected. Astrocytes treated with a miRNA-146-5p inhibitor rescued IRAK-1 and changed TRAF-6 steady-state levels that correlated with the induction of IL-6, IL-1β, and CXCL1 production, indicating that miRNA-146a-5p operates anti-inflammatory functions through a NF-κB pathway negative feedback loop. Overall, we report a panel of circulating miRNAs that correlated with Aβ_1-42 peptides' presence in the hippocampus and provide mechanistic insights into miRNA-146a-5p biological function in the development of the early stage of sporadic AD.

Stable Expression of dmiR-283 in the Brain Promises Positive Effects in Endurance Exercise on Sleep-Wake Behavior in Aging Drosophila

Sleep-wake stability is imbalanced with natural aging, and microRNAs (miRNAs) play important roles in cell proliferation, apoptosis, and aging; however, the biological functions of miRNAs in regulating aging-related sleep-wake behavior remain unexplored. This study varied the expression pattern of dmiR-283 in Drosophila and the result showed that the aging decline in sleep-wake behavior was caused by the accumulation of brain dmiR-283 expression, whereas the core clock genes cwo and Notch signaling pathway might be suppressed, which regulate the aging process. In addition, to identify exercise intervention programs of Drosophila that promote healthy aging, mir-283^SP/+ and Pdf > mir-283^SP flies were driven to perform endurance exercise for a duration of 3 weeks starting at 10 and 30 days, respectively. The results showed that exercise starting in youth leads to an enhanced amplitude of sleep-wake rhythms, stable periods, increased activity frequency upon awakening, and the suppression of aging brain dmiR-283 expression in mir-283^SP/+ middle-aged flies. Conversely, exercise performed when the brain dmiR-283 reached a certain accumulation level showed ineffective or negative effects. In conclusion, the accumulation of dmiR-283 expression in the brain induced an age-dependent decline in sleep-wake behavior. Endurance exercise commencing in youth counteracts the increase in dmiR-283 in the aging brain, which ameliorates the deterioration of sleep-wake behavior during aging.

An Update on Peripheral Blood Extracellular Vesicles as Biomarkers for Parkinson's Disease Diagnosis

Parkinson's disease (PD) is the world's second primary neurodegenerative disease, and the diagnosis and treatment of PD have become mainstream research. Over the past decades, several studies have identified potential biomarkers for diagnosing PD. Among them, extracellular vesicles (EVs) can carry specific biomarkers reflecting the physiological and pathological state of the body. Due to the blood-brain barrier (BBB) limitation, peripheral blood is limited in diagnosing neurodegenerative diseases. With the increasing research on EVs, their ability to pass through BBB indicated that peripheral blood could depict disease status like cerebrospinal fluid (CSF). Peripheral blood is a clinically available sample and has recently been widely used by researchers in various studies. In this review, we summarized previous studies on PD diagnosis biomarkers in peripheral blood EVs and evaluated their diagnostic value. Some EV surface markers were also described, which can extract EVs from specific cell origins. In addition, the combination of several biomarkers demonstrated good diagnostic performance in PD diagnosis compared with a single biomarker, suggesting the focus of future research.

Recent advances in the functional explorations of nuclear microRNAs

Approximately 22 nucleotide-long non-coding small RNAs (ncRNAs) play crucial roles in physiological and pathological activities, including microRNAs (miRNAs). Long ncRNAs often stay in the cytoplasm, modulating post-transcriptional gene expression. Briefly, miRNA binds with the target mRNA and builds a miRNA-induced silencing complex to silence the transcripts or prevent their translation. Interestingly, data from recent animal and plant studies suggested that mature miRNAs are present in the nucleus, where they regulate transcriptionally whether genes are activated or silenced. This significantly broadens the functional range of miRNAs. Here, we reviewed and summarized studies on the functions of nuclear miRNAs to better understand the modulatory networks associated with nuclear miRNAs.

Mir155 regulates osteogenesis and bone mass phenotype via targeting S1pr1 gene

MicroRNA-155 (miR155) is overexpressed in various inflammatory diseases and cancer, in which bone resorption and osteolysis are frequently observed. However, the role of miR155 on osteogenesis and bone mass phenotype is still unknown. Here, we report a low bone mass phenotype in the long bone of Mir155-Tg mice compared with wild-type mice. In contrast, Mir155-KO mice showed a high bone mass phenotype and protective effect against inflammation-induced bone loss. Mir155-KO mice showed robust bone regeneration in the ectopic and orthotopic model, but Mir155-Tg mice showed compromised bone regeneration compared with the wild-type mice. Similarly, the osteogenic differentiation potential of bone marrow stromal stem cells (BMSCs) from Mir155-KO mice was robust and Mir155-Tg was compromised compared with that of wild-type mice. Moreover, Mir155 knockdown in BMSCs from wild-type mice showed higher osteogenic differentiation potential, supporting the results from Mir155-KO mice. TargetScan analysis predicted sphingosine 1-phosphate receptor-1 (S1pr1) as a target gene of Mir155, which was further confirmed by luciferase assay and Mir155 knockdown. S1pr1 overexpression in BMSCs robustly promoted osteogenic differentiation without affecting cell viability and proliferation. Furthermore, osteoclastogenic differentiation of Mir155-Tg bone marrow-derived macrophages was inhibited compared with that of wild-type mice. Thus, Mir155 showed a catabolic effect on osteogenesis and bone mass phenotype via interaction with the S1pr1 gene, suggesting inhibition of Mir155 as a potential strategy for bone regeneration and bone defect healing.

Ageing at Molecular Level: Role of MicroRNAs

The progression of age triggers a vast number of diseases including cardiovascular, cancer, and neurodegenerative disorders. Regardless of our plentiful knowledge about age-related diseases, little is understood about molecular pathways that associate the ageing process with various diseases. Several cellular events like senescence, telomere dysfunction, alterations in protein processing, and regulation of gene expression are common between ageing and associated diseases. Accumulating information on the role of microRNAs (miRNAs) suggests targeting miRNAs can aid our understanding of the interplay between ageing and associated diseases. In the present chapter, we have attempted to explore the information available on the role of miRNAs in ageing of various tissues/organs and diseases and understand the molecular mechanism of ageing.

Clinical Ageing

Ageing is generally characterised by the declining ability to respond to stress, increasing homeostatic imbalance, and increased risk of ageing-associated diseases . Mechanistically, the lifelong accumulation of a wide range of molecular and cellular impairments leads to organismal senescence. The aging population poses a severe medical concern due to the burden it places on healthcare systems and the general public as well as the prevalence of diseases and impairments associated with old age. In this chapter, we discuss organ failure during ageing as well as ageing of the hypothalamic-pituitary-adrenal axis and drugs that can regulate it. A much-debated subject is about ageing and regeneration. With age, there is a gradual decline in the regenerative properties of most tissues. The goal of regenerative medicine is to restore cells, tissues, and structures that are lost or damaged after disease, injury, or ageing. The question arises as to whether this is due to the intrinsic ageing of stem cells or, rather, to the impairment of stem-cell function in the aged tissue environment. The risk of having a stroke event doubles each decade after the age of 55. Therefore, it is of great interest to develop neurorestorative therapies for stroke which occurs mostly in elderly people. Initial enthusiasm for stimulating restorative processes in the ischaemic brain with cell-based therapies has meanwhile converted into a more balanced view, recognising impediments related to survival, migration, differentiation, and integration of therapeutic cells in the hostile aged brain environment. Therefore, a current lack of understanding of the fate of transplanted cells means that the safety of cell therapy in stroke patients is still unproven. Another issue associated with ischaemic stroke is that patients at risk for these sequels of stroke are not duly diagnosed and treated due to the lack of reliable biomarkers. However, recently neurovascular unit-derived exosomes in response to Stroke and released into serum are new plasma genetic and proteomic biomarkers associated with ischaemic stroke. The second valid option, which is also more economical, is to invest in prevention.

Role of Autophagy in HIV-1 and Drug Abuse-Mediated Neuroinflammaging

Chronic low-grade inflammation remains an essential feature of HIV-1 infection under combined antiretroviral therapy (cART) and contributes to the accelerated cognitive defects and aging in HIV-1 infected populations, indicating cART limitations in suppressing viremia. Interestingly, ~50% of the HIV-1 infected population on cART that develops cognitive defects is complicated by drug abuse, involving the activation of cells in the central nervous system (CNS) and neurotoxin release, altogether leading to neuroinflammation. Neuroinflammation is the hallmark feature of many neurodegenerative disorders, including HIV-1-associated neurocognitive disorders (HAND). Impaired autophagy has been identified as one of the underlying mechanisms of HAND in treated HIV-1-infected people that also abuse drugs. Several lines of evidence suggest that autophagy regulates CNS cells' responses and maintains cellular hemostasis. The impairment of autophagy is associated with low-grade chronic inflammation and immune senescence, a known characteristic of pathological aging. Therefore, autophagy impairment due to CNS cells, such as neurons, microglia, astrocytes, and pericytes exposure to HIV-1/HIV-1 proteins, cART, and drug abuse could have combined toxicity, resulting in increased neuroinflammation, which ultimately leads to accelerated aging, referred to as neuroinflammaging. In this review, we focus on the potential role of autophagy in the mechanism of neuroinflammaging in the context of HIV-1 and drug abuse.

Understanding the Intricate Role of Exosomes in Pathogenesis of Alzheimer's Disease

Alzheimer's disease causes loss of memory and deterioration of mental abilities is utmost predominant neurodegenerative disease accounting 70-80% cases of dementia. The appearance of plaques of amyloid-β and neurofibrillary tangles in the brain post-mortems of Alzheimer's patients established them as key participants in the etiology of Alzheimer's disease. Exosomes exist as extracellular vesicles of nano-size which are present throughout the body. Exosomes are known to spread toxic hyperphosphorylated tau and amyloid-β between the cells and are linked to the loss of neurons by inducing apoptosis. Exosomes have progressed from cell trashcans to multifunctional organelles which are involved in various functions like internalisation and transmission of macromolecules such as lipids, proteins, and nucleic acids. This review covers current findings on relationship of exosomes in biogenesis and angiogenesis of Alzheimer's disease and functions of exosomes in the etiology of AD. Furthermore, the roles of exosomes in development, diagnosis, treatment, and its importance as therapeutic targets and biomarkers for Alzheimer's disease have also been highlighted.

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.

Forensic age estimation from human blood using age-related microRNAs and circular RNAs markers

Aging is a complicated process characterized by progressive and extensive changes in physiological homeostasis at the organismal, tissue, and cellular levels. In modern society, age estimation is essential in a large variety of legal rights and duties. Accumulating evidence suggests roles for microRNAs (miRNAs) and circular RNAs (circRNAs) in regulating numerous processes during aging. Here, we performed circRNA sequencing in two age groups and analyzed microarray data of 171 healthy subjects (17-104 years old) downloaded from Gene Expression Omnibus (GEO) and ArrayExpress databases with integrated bioinformatics methods. A total of 1,403 circular RNAs were differentially expressed between young and old groups, and 141 circular RNAs were expressed exclusively in elderly samples while 10 circular RNAs were expressed only in young subjects. Based on their expression pattern in these two groups, the circular RNAs were categorized into three classes: age-related expression between young and old, age-limited expression-young only, and age-limited expression-old only. Top five expressed circular RNAs among three classes and a total of 18 differentially expressed microRNAs screened from online databases were selected to validate using RT-qPCR tests. An independent set of 200 blood samples (20-80 years old) was used to develop age prediction models based on 15 age-related noncoding RNAs (11 microRNAs and 4 circular RNAs). Different machine learning algorithms for age prediction were applied, including regression tree, bagging, support vector regression (SVR), random forest regression (RFR), and XGBoost. Among them, random forest regression model performed best in both training set (mean absolute error = 3.68 years, r = 0.96) and testing set (MAE = 6.840 years, r = 0.77). Models using one single type of predictors, circular RNAs-only or microRNAs-only, result in bigger errors. Smaller prediction errors were shown in males than females when constructing models according to different-sex separately. Putative microRNA targets (430 genes) were enriched in the cellular senescence pathway and cell homeostasis and cell differentiation regulation, indirectly indicating that the microRNAs screened in our study were correlated with development and aging. This study demonstrates that the noncoding RNA aging clock has potential in predicting chronological age and will be an available biological marker in routine forensic investigation to predict the age of biological samples.