MiRNA-137-mediated modulation of mitochondrial dynamics regulates human neural stem cell fate

Pleiotrophin inhibited chondrogenic differentiation potential of dental pulp stem cells

OBJECTIVE

Studies have shown that the levels of pleiotrophin (PTN) are greatly elevated in the synovial fluid and cartilage in osteoarthritis. Therefore, the purpose of this study was to investigate the effect and mechanism of PTN on the chondrogenic differentiation of DPSCs in inflammatory and normal microenvironments.

MATERIALS AND METHODS

A lentiviral vector was used to deplete or overexpress PTN in DPSCs. The inflammatory microenvironment was simulated in vitro by the addition of IL-1β to the culture medium. The chondrogenic differentiation potential was assessed using Alcian Blue staining and the main chondrogenic markers. A dual-luciferase reporter assay was used to explore the relationship between miR-137 and PTN.

RESULTS

The results showed that 0.1 ng/mL IL-1β treatment during chondrogenic induction greatly impaired the chondrogenic differentiation of DPSCs. Supplementation with PTN and PTN overexpression inhibited chondrogenic differentiation of DPSCs, while PTN depletion promoted chondrogenic differentiation. MiR-137 negatively regulated the expression of PTN by binding to the 3'UTR of its mRNA. Moreover, miR-137 promoted chondrogenic differentiation of DPSCs in normal and inflammatory microenvironments.

CONCLUSION

Our results suggest that PTN may play an inhibitory role in the chondrogenic differentiation of DPSCs in normal and inflammatory microenvironments, which is regulated by miR-137.

Repeated Ketamine Anesthesia during the Neonatal Period Impairs Hippocampal Neurogenesis and Long-Term Neurocognitive Function by Inhibiting Mfn2-Mediated Mitochondrial Fusion in Neural Stem Cells

The mechanism of ketamine-induced neurotoxicity development remains elusive. Mitochondrial fusion/fission dynamics play a critical role in regulating neurogenesis. Therefore, this study was aimed to evaluate whether mitochondrial dynamics were involved in ketamine-induced impairment of neurogenesis in neonatal rats and long-term synaptic plasticity dysfunction. In the in vivo study, postnatal day 7 (PND-7) rats received intraperitoneal (i.p.) injection of 40 mg/kg ketamine for four consecutive times at 1 h intervals. The present findings revealed that ketamine induced mitochondrial fusion dysfunction in hippocampal neural stem cells (NSCs) by downregulating Mitofusin 2 (Mfn2) expression. In the in vitro study, ketamine treatment at 100 μM for 6 h significantly decreased the Mfn2 expression, and increased ROS generation, decreased mitochondrial membrane potential and ATP levels in cultured hippocampal NSCs. For the interventional study, lentivirus (LV) overexpressing Mfn2 (LV-Mfn2) or control LV vehicle was microinjected into the hippocampal dentate gyrus (DG) 4 days before ketamine administration. Targeted Mfn2 overexpression in the DG region could restore mitochondrial fusion in NSCs and reverse the inhibitory effect of ketamine on NSC proliferation and its faciliatory effect on neuronal differentiation. In addition, synaptic plasticity was evaluated by transmission electron microscopy, Golgi-Cox staining and long-term potentiation (LTP) recordings at 24 h after the end of the behavioral test. Preconditioning with LV-Mfn2 improved long-term cognitive dysfunction after repeated neonatal ketamine exposure by reversing the inhibitory effect of ketamine on synaptic plasticity in the hippocampal DG. The present findings demonstrated that Mfn2-mediated mitochondrial fusion dysfunction plays a critical role in the impairment of long-term neurocognitive function and synaptic plasticity caused by repeated neonatal ketamine exposure by interfering with hippocampal neurogenesis. Thus, Mfn2 might be a novel therapeutic target for the prevention of the developmental neurotoxicity of ketamine.

A landscape of mouse mitochondrial small non-coding RNAs

Small non-coding RNAs (ncRNAs), particularly miRNAs, play key roles in a plethora of biological processes both in health and disease. Although largely operative in the cytoplasm, emerging data indicate their shuttling in different subcellular compartments. Given the central role of mitochondria in cellular homeostasis, here we systematically profiled their small ncRNAs content across mouse tissues that largely rely on mitochondria functioning. The ubiquitous presence of piRNAs in mitochondria (mitopiRNA) of somatic tissues is reported for the first time, supporting the idea of a strong and general connection between mitochondria biology and piRNA pathways. Then, we found groups of tissue-shared and tissue-specific mitochondrial miRNAs (mitomiRs), potentially related to the "basic" or "cell context dependent" biology of mitochondria. Overall, this large data platform will be useful to deepen the knowledge about small ncRNAs processing and their governed regulatory networks contributing to mitochondria functions.

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.

Early-Stage Application of Agomir-137 Promotes Locomotor Recovery in a Mouse Model of Motor Cortex Injury

Traumatic brain injury (TBI) is a significant risk factor for neurodegenerative disorders, and patients often experience varying degrees of motor impairment. MiR-137, a broadly conserved and brain-enriched miRNA, is a key regulator in neural development and in various neurological diseases. Following TBI, the expression of miR-137 is dramatically downregulated. However, whether miR-137 is a therapeutic target for TBI still remains unknown. Here, for the first time, we demonstrate that intranasal administration of miR-137 agomir (a mimic) in the early stage (0-7 days) of TBI effectively inhibits glial scar formation and improves neuronal survival, while early-stage administration of miR-137 antagomir (an inhibitor) deteriorates motor impairment. This study elucidates the therapeutic potential of miR-137 mimics in improving locomotor recovery following motor cortex injury.

Therapeutic potential for KCC2-targeted neurological diseases

Patients with neurological diseases, such as schizophrenia, tend to show low K+-Cl- co-transporter 2 (KCC2) levels in the brain. The cause of these diseases has been associated with stress and neuroinflammation. However, since the pathogenesis of these diseases is not yet fully investigated, drug therapy is still limited to symptomatic therapy. Targeting KCC2, which is mainly expressed in the brain, seems to be an appropriate approach in the treatment of these diseases. In this review, we aimed to discuss about stress and inflammation, KCC2 and Gamma-aminobutyric acid (GABA) function, diseases which decrease the KCC2 levels in the brain, factors that regulate KCC2 activity, and the possibility to overcome neuronal dysfunction targeting KCC2. We also aimed to discuss the relationships between neurological diseases and LPS caused by Porphyromonas gingivalis (P. g), which is a type of oral bacterium. Clinical trials on oxytocin, sirtuin 1 (SIRT1) activator, and transient receptor potential cation channel subfamily V Member 1 activator have been conducted to develop effective treatment methods. We believe that KCC2 modulators that regulate mitochondria, such as oxytocin, glycogen synthase kinase 3β (GSK3β), and SIRT1, can be potential targets for neurological diseases.

Does exercise influence skeletal muscle by modulating mitochondrial functions via regulating MicroRNAs? A systematic review

BACKGROUND

Sarcopenia is the accelerated loss of muscle mass, strength and function. Mitochondrial dysfunction was related to the progression of sarcopenia; meanwhile, microRNAs were regarded as core roles in regulating mitochondrial function. Physical exercise is a well-accepted approach to attenuate sarcopenia, yet very few studies depict the molecular mechanisms. The aim of this systematic review is to explore the potential relationships among physical exercise, mitochondrial function, and microRNAs, which may give new insight for retarding sarcopenia.

METHODS

A systematic literature search was performed in PubMed, Embase and Web of Science. The keywords were combined as "(microRNA OR miR) AND mitochondri* AND muscle AND exercise" and searched in all fields. PRISMA guidelines were followed. Information was extracted from the included studies for review.

RESULTS

In this review, 18 preclinical studies and 5 clinical studies were included. Most of the included studies suggested that effective physical exercise had positive effects on mitochondrial functions by regulating microRNAs. The results showed that 12 microRNAs improved mitochondrial functions, while 18 microRNAs suppressed them. Meanwhile, the results showed that 5 microRNAs improved muscle performance.

CONCLUSIONS

This systematic review provides an up-to-date sequential overview and highlights the potential relationship among exercise, mitochondrial function, and microRNAs in muscle. Meanwhile, evidence revealed that physical exercise can improve muscle performance by up-regulating mitochondrial functions, especially mitochondrial biogenesis, through modulating microRNAs.

miR-153-3p suppresses the differentiation and proliferation of neural stem cells via targeting GPR55

Alzheimer's disease is the most frequent neurodegenerative disease and is characterized by progressive cognitive impairment and decline. NSCs (neural stem cells) serve as beneficial and promising adjuncts to treat Alzheimer's disease. This study aimed to determine the role of miR-153-3p expression in NSC differentiation and proliferation. We illustrated that miR-153-3p was decreased and GPR55 was upregulated during NSC differentiation. IL-1β can induce miR-153-3p expression. Luciferase reporter analysis noted that elevated expression of miR-153-3p significantly inhibited the luciferase value of the WT reporter plasmid but did not change the luciferase value of the mut reporter plasmid. Ectopic miR-153-3p expression suppressed GPR55 expression in NSCs and identified GPR55 as a direct target gene of miR-153-3p. Ectopic expression of miR-153-3p inhibited NSC growth and differentiation into astrocytes and neurons. Elevated expression of miR-153-3p induced the release of proinflammatory cytokines, such as TNF-α, IL-1β and IL-6, in NSCs. Furthermore, miR-153-3p inhibited NSC differentiation and proliferation by targeting GPR55 expression. These data suggested that miR-153-3p may act as a clinical target for the therapeutics of neurodegenerative diseases.

Exosome-derived circKIF20B suppresses gefitinib resistance and cell proliferation in non-small cell lung cancer

BACKGROUND

The gefitinib resistance mechanism in non-small cell lung cancer (NSCLC) remains unclear, albeit exosomal circular RNA (circRNA) is known to possibly play a vital role in it.

METHODS

We employed high-throughput sequencing techniques to detect the expressions of exosomal circRNA both in gefitinib-resistant and gefitinib-sensitive cells in this study. The circKIF20B expression was determined in serum exosomes and tissues of patients by qRT-PCR. The structure, stability, and intracellular localization of circKIF20B were verified by Sanger sequencing, Ribonuclease R (RNase R)/actinomycin D (ACTD) treatments, and Fluorescence in situ hybridization (FISH). The functions of circKIF20B were investigated by 5-Ethynyl-20-deoxyuridine (EdU), flow cytometry, Cell Counting Kit-8 (CCK-8), oxygen consumption rate (OCR), and xenograft model. Co-culture experiments were performed to explore the potential ability of exosomal circKIF20B in treating gefitinib resistance. The downstream targets of circKIF20B were determined by luciferase assay, RNA pulldown, and RNA immunoprecipitation (RIP).

RESULTS

We found that circKIF20B was poorly expressed in the serum exosomes of gefitinib-resistant patients (n = 24) and the tumor tissues of patients with NSCLC (n = 85). CircKIF20B was negatively correlated with tumor size and tumor stage. Decreasing circKIF20B was found to promote gefitinib resistance by accelerating the cell cycle, inhibiting apoptosis, and enhancing mitochondrial oxidative phosphorylation (OXPHOS), whereas increasing circKIF20B was found to restore gefitinib sensitivity. Mechanistically, circKIF20B is bound to miR-615-3p for regulating the MEF2A and then altering the cell cycle, apoptosis, and mitochondrial OXPHOS. Overexpressing circKIF20B parental cells can restore sensitivity to gefitinib in the recipient cells by upregulating the exosomal circKIF20B expression.

CONCLUSIONS

This study revealed a novel mechanism of circKIF20B/miR-615-3p/MEF2A signaling axis involving progression of gefitinib resistance in NSCLC. Exosomal circKIF20B is expected to be an easily accessible and alternative liquid biopsy candidate and potential therapeutic target in gefitinib-resistant NSCLC. The schematic diagram of mechanism in this study. Exosomal circKIF20B inhibits gefitinib resistance and cell proliferation by arresting the cell cycle, promoting apoptosis, and reducing OXPHOS via circKIF20B/miR-615-3p/MEF2A axis in NSCLC.

Understanding the Roles and Regulation of Mitochondrial microRNAs (MitomiRs) in Neurodegenerative Diseases: Current Status and Advances

MicroRNAs (miRNA) are a class of small non-coding RNA, roughly 21 - 22 nucleotides in length, which are master gene regulators. These miRNAs bind to the mRNA's 3' - untranslated region and regulate post-transcriptional gene regulation, thereby influencing various physiological and cellular processes. Another class of miRNAs known as mitochondrial miRNA (MitomiRs) has been found to either originate from the mitochondrial genome or be translocated directly into the mitochondria. Although the role of nuclear DNA encoded miRNA in the progression of various neurological diseases such as Parkinson's disease, Alzheimer's disease, Huntington's disease, etc. is well known, accumulating evidence suggests the possible role of deregulated mitomiRs in the progression of various neurodegenerative diseases with unknown mechanism. We have attempted to outline the current state of mitomiRs role in controlling mitochondrial gene expression and function through this review, paying particular attention to their contribution to neurological processes, their etiology, and their potential therapeutic use.

miR-6216 Regulates Neural Stem Cell Proliferation by Targeting RAB6B

Neural stem cells (NSCs) are a class of self-renewing, multipotent and undifferentiated progenitor cells that retain the capacity to both glial and neuronal lineages. MicroRNAs (miRNAs) are small non-coding RNAs that play an important role in stem cell fate determination and self-renewal. Our previous RNA-seq data indicated that the expression of miR-6216 was decreased in denervated hippocampal exosomes compared with normal. However, whether miR-6216 participates in regulating NSC function remains to be elucidated. In this study, we demonstrated that miR-6216 negatively regulates RAB6B expression. Forced overexpression of miR-6216 inhibited NSC proliferation, and overexpression of RAB6B promoted NSC proliferation. These findings suggest that miR-6216 played an important role in regulating NSC proliferation via targeting RAB6B, and improve the understanding of the miRNA-mRNA regulatory network that affects NSC proliferation.

Non-coding RNAs regulating mitochondrial function in cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of disease-related death worldwide and a significant obstacle to improving patients' health and lives. Mitochondria are core organelles for the maintenance of myocardial tissue homeostasis, and their impairment and dysfunction are considered major contributors to the pathogenesis of various CVDs, such as hypertension, myocardial infarction, and heart failure. However, the exact roles of mitochondrial dysfunction involved in CVD pathogenesis remain not fully understood. Non-coding RNAs (ncRNAs), particularly microRNAs, long non-coding RNAs, and circular RNAs, have been shown to be crucial regulators in the initiation and development of CVDs. They can participate in CVD progression by impacting mitochondria and regulating mitochondrial function-related genes and signaling pathways. Some ncRNAs also exhibit great potential as diagnostic and/or prognostic biomarkers as well as therapeutic targets for CVD patients. In this review, we mainly focus on the underlying mechanisms of ncRNAs involved in the regulation of mitochondrial functions and their role in CVD progression. We also highlight their clinical implications as biomarkers for diagnosis and prognosis in CVD treatment. The information reviewed herein could be extremely beneficial to the development of ncRNA-based therapeutic strategies for CVD patients.

Emerging evidence on the effects of plant-derived microRNAs in colorectal cancer: a review

Food nutrition and human health are still interesting international issues. Early detection, risk assessment and diet are vital to mitigate the load of intestinal diseases and enhance the quality of life. Plant-derived microRNAs could be transferred to mammalian organisms by cross-kingdom regulation which adjusts relevant target genes for their participation in the process of carcinogenesis. But the mechanism of plant-derived microRNAs in colorectal cancer is still unclear. This review aims to summarize the current pathways of plant-derived microRNAs in colorectal cancer including intestinal bacteria, the tumor microenvironment, plant active substances and protein, discuss the direct or indirect effects of plant-derived microRNAs on the occurrence and/or progression of colorectal cancer and explain why plant-derived microRNAs can be used as a potential anti-cancer agent. Moreover, the drawbacks of plant-derived microRNAs are also discussed in terms of both edible plants and synthetic delivery vectors for RNAi interference technology for human disease treatment. This review will provide a potential way for plant-derived microRNAs to target colorectal cancer.

Non-Coding RNAs in the Regulation of Hippocampal Neurogenesis and Potential Treatment Targets for Related Disorders

Non-coding RNAs (ncRNAs), including miRNAs, lncRNAs, circRNAs, and piRNAs, do not encode proteins. Nonetheless, they have critical roles in a variety of cellular activities-such as development, neurogenesis, degeneration, and the response to injury to the nervous system-via protein translation, RNA splicing, gene activation, silencing, modifications, and editing; thus, they may serve as potential targets for disease treatment. The activity of adult neural stem cells (NSCs) in the subgranular zone of the hippocampal dentate gyrus critically influences hippocampal function, including learning, memory, and emotion. ncRNAs have been shown to be involved in the regulation of hippocampal neurogenesis, including proliferation, differentiation, and migration of NSCs and synapse formation. The interaction among ncRNAs is complex and diverse and has become a major topic within the life science. This review outlines advances in research on the roles of ncRNAs in modulating NSC bioactivity in the hippocampus and discusses their potential applications in the treatment of illnesses affecting the hippocampus.

It takes two to tango: Widening our understanding of the onset of schizophrenia from a neuro-angiogenic perspective

Schizophrenia is a chronic debilitating mental disorder characterized by perturbations in thinking, perception, and behavior, along with brain connectivity deficiencies, neurotransmitter dysfunctions, and loss of gray brain matter. To date, schizophrenia has no cure and pharmacological treatments are only partially efficacious, with about 30% of patients describing little to no improvement after treatment. As in most neurological disorders, the main descriptions of schizophrenia physiopathology have been focused on neural network deficiencies. However, to sustain proper neural activity in the brain, another, no less important network is operating: the vast, complex and fascinating vascular network. Increasing research has characterized schizophrenia as a systemic disease where vascular involvement is important. Several neuro-angiogenic pathway disturbances have been related to schizophrenia. Alterations, ranging from genetic polymorphisms, mRNA, and protein alterations to microRNA and abnormal metabolite processing, have been evaluated in plasma, post-mortem brain, animal models, and patient-derived induced pluripotent stem cell (hiPSC) models. During embryonic brain development, the coordinated formation of blood vessels parallels neuro/gliogenesis and results in the structuration of the neurovascular niche, which brings together physical and molecular signals from both systems conforming to the Blood-Brain barrier. In this review, we offer an upfront perspective on distinctive angiogenic and neurogenic signaling pathways that might be involved in the biological causality of schizophrenia. We analyze the role of pivotal angiogenic-related pathways such as Vascular Endothelial Growth Factor and HIF signaling related to hypoxia and oxidative stress events; classic developmental pathways such as the NOTCH pathway, metabolic pathways such as the mTOR/AKT cascade; emerging neuroinflammation, and neurodegenerative processes such as UPR, and also discuss non-canonic angiogenic/axonal guidance factor signaling. Considering that all of the mentioned above pathways converge at the Blood-Brain barrier, reported neurovascular alterations could have deleterious repercussions on overall brain functioning in schizophrenia.

Drp1 Regulated Mitochondrial Hypofission Promotes the Invasion and Proliferation of Growth Hormone-Secreting Pituitary Adenomas via Activating STAT3

The invasiveness and high proliferation rate of growth hormone-secreting pituitary adenomas (GHPAs) are closely related to poor prognosis in patients. We previously reported that abnormal glycolysis participates in this process; however, the role of mitochondria in the invasion and proliferation of GHPAs remains unknown. In the current study, stereological methods were first used to quantitatively calculate the number and morphology of mitochondria. The results revealed that the numbers, volumes and membrane areas of mitochondria were decreased in invasive GHPAs (IGHPAs) samples compared to noninvasive GHPAs (NIGHPAs) samples. Furthermore, significantly downregulated mRNA and protein levels of dynamin-related protein 1 (Drp1) were detected in IGHPAs, but no notable changes in fusion related molecules (Mfn1, Mfn2 and OPA1) were detected, suggesting that the abnormal mitochondrial dynamics in IGHPAs are characterized by hypofission. Mitochondrial hypofission caused by Mdivi-1, a specific Drp1 inhibitor, enhanced the invasion and proliferation of GH3 cell lines and primary cells from patients with GHPAs in vitro and in vivo, while overexpression of Drp1 reversed these processes. Mechanistically, mitochondrial hypofission might activate signal transducer and activator of transcription 3 (STAT3). Specifically, elevated nuclear pSTAT3^Y705 may promote GH3 cell invasion by upregulating the activity of matrix metalloproteinase 2/9, and elevated mitochondrial pSTAT3^S727 may promote GH3 cell proliferation by inhibiting the mitochondria-dependent apoptotic pathway. Taken together, our findings suggest that mitochondrial hypofission induced by Drp1 might strengthen the invasion and proliferation of GHPA tumor cells by activating STAT3, providing us with a new perspective on how mitochondria regulate the development of IGHPAs.

Beyond AOPs: A Mechanistic Evaluation of NAMs in DART Testing

New Approach Methodologies (NAMs) promise to offer a unique opportunity to enable human-relevant safety decisions to be made without the need for animal testing in the context of exposure-driven Next Generation Risk Assessment (NGRA). Protecting human health against the potential effects a chemical may have on embryo-foetal development and/or aspects of reproductive biology using NGRA is particularly challenging. These are not single endpoint or health effects and risk assessments have traditionally relied on data from Developmental and Reproductive Toxicity (DART) tests in animals. There are numerous Adverse Outcome Pathways (AOPs) that can lead to DART, which means defining and developing strict testing strategies for every AOP, to predict apical outcomes, is neither a tenable goal nor a necessity to ensure NAM-based safety assessments are fit-for-purpose. Instead, a pragmatic approach is needed that uses the available knowledge and data to ensure NAM-based exposure-led safety assessments are sufficiently protective. To this end, the mechanistic and biological coverage of existing NAMs for DART were assessed and gaps to be addressed were identified, allowing the development of an approach that relies on generating data relevant to the overall mechanisms involved in human reproduction and embryo-foetal development. Using the knowledge of cellular processes and signalling pathways underlying the key stages in reproduction and development, we have developed a broad outline of endpoints informative of DART. When the existing NAMs were compared against this outline to determine whether they provide comprehensive coverage when integrated in a framework, we found them to generally cover the reproductive and developmental processes underlying the traditionally evaluated apical endpoint studies. The application of this safety assessment framework is illustrated using an exposure-led case study.

Mitochondrial Function Differences between Tumor Tissue of Human Metastatic and Premetastatic CRC

Simple Summary

Metastasis is an important cause of death from colorectal cancer (CRC). Mitochondria, which are important organelles of cells, play a key role in the metastatic transformation of cancer cells. We aimed to evaluate the adaptations associated with mitochondrial function in tumor tissues from advanced stages of human CRC and whether they could ultimately be used as a therapeutic target in metastatic CRC. We have compared the mitochondrial functionality parameters in tumor tissue samples and the normal adjacent tissue of advanced CRC patients with no radio- or chemotherapy treatment before surgery. Notable differences in mitochondrial functionality were detected between the samples of adjacent tissue versus tumor tissue from metastatic CRC patients. These findings suggest a shift in the mitochondrial function profile occurring in tumor tissue once the metastatic stage has been reached. These changes contribute to promote and maintain the metastatic phenotype, with evidence of mitochondrial function impairment in tumor tissue in the metastatic stage samples.

Abstract

Most colorectal cancer (CRC) patients die as a consequence of metastasis. Mitochondrial dysfunction could enhance cancer development and metastatic progression. We aimed to evaluate the adaptations associated with mitochondrial function in tumor tissues from stages III and IV of human CRC and whether they could ultimately be used as a therapeutic target in metastatic colorectal cancer (mCRC). We analyzed the protein levels by Western blotting and the enzymatic activities of proteins involved in mitochondrial function, as well as the amount of mitochondrial DNA (mtDNA), by real-time PCR, analyzing samples of non-tumor adjacent tissue and tumor tissue from stages III and IV CRC patients without radio- or chemotherapy treatment prior to surgery. Our data indicate that the tumor tissue of pre-metastatic stage III CRC exhibited an oxidant metabolic profile very similar to the samples of non-tumor adjacent tissue of both stages. Notable differences in the protein expression levels of ATPase, IDH2, LDHA, and SIRT1, as well as mtDNA amount, were detected between the samples of non-tumor adjacent tissue and tumor tissue from metastatic CRC patients. These findings suggest a shift in the oxidative metabolic profile that takes place in the tumor tissue once the metastatic stage has been reached. Tumor tissue oxidative metabolism contributes to promote and maintain the metastatic phenotype, with evidence of mitochondrial function impairment in stage IV tumor tissue.

The regulatory roles of microRNAs toward pathogenesis and treatments in Huntington's disease

Huntington's disease (HD) is one of neurodegenerative diseases, and is defined as a monogenetic disease due to the mutation of Huntingtin gene. This disease affects several cellular functions in neurons, and further influences motor and cognitive ability, leading to the suffering of devastating symptoms in HD patients. MicroRNA (miRNA) is a non-coding RNA, and is responsible for gene regulation at post-transcriptional levels in cells. Since one miRNA targets to several downstream genes, it may regulate different pathways simultaneously. As a result, it raises a potential therapy for different diseases using miRNAs, especially for inherited diseases. In this review, we will not only introduce the update information of HD and miRNA, but also discuss the development of potential miRNA-based therapy in HD. With the understanding toward the progression of miRNA studies in HD, we anticipate it may provide an insight to treat this devastating disease, even applying to other genetic diseases.

New insights into mitophagy and stem cells

Mitophagy is a specific autophagic phenomenon in which damaged or redundant mitochondria are selectively cleared by autophagic lysosomes. A decrease in mitophagy can accelerate the aging process. Mitophagy is related to health and longevity and is the key to protecting stem cells from metabolic stress damage. Mitophagy decreases the metabolic level of stem cells by clearing active mitochondria, so mitophagy is becoming increasingly necessary to maintain the regenerative capacity of old stem cells. Stem cell senescence is the core problem of tissue aging, and tissue aging occurs not only in stem cells but also in transport amplifying cell chambers and the stem cell environment. The loss of the autophagic ability of stem cells can cause the accumulation of mitochondria and the activation of the metabolic state as well as damage the self-renewal ability and regeneration potential of stem cells. However, the claim remains controversial. Mitophagy is an important survival strategy against nutrient deficiency and starvation, and mitochondrial function and integrity may affect the viability, proliferation and differentiation potential, and longevity of normal stem cells. Mitophagy can affect the health and longevity of the human body, so the number of studies in this field has increased, but the mechanism by which mitophagy participates in stem cell development is still not fully understood. This review describes the potential significance of mitophagy in stem cell developmental processes, such as self-renewal, differentiation and aging. Through this work, we discovered the role and mechanism of mitophagy in different types of stem cells, identified novel targets for killing cancer stem cells and curing cancer, and provided new insights for future research in this field.

MicroRNAs mediated regulation of glutathione peroxidase 7 expression and its changes during adipogenesis

Glutathione peroxidase 7 (GPx7) acts as an intracellular stress sensor/transmitter and plays an important role in adipocyte differentiation and the prevention of obesity related pathologies. For this reason, finding the regulatory mechanisms that control GPx7 expression is of great importance. As microRNAs (miRNAs) could participate in the regulation of GPx7 expression, we studied the inhibition of GPx7 expression by four selected miRNAs with relation to obesity and adipogenesis. The effect of the transfection of selected miRNAs mimics on GPx7 expression was tested in three cell models (HEK293, SW480, AT-MSC). The interaction of selected miRNAs with the 3'UTR of GPx7 was followed up on using a luciferase gene reporter assay. In addition, the levels of GPx7 and selected miRNAs in adipose tissue mesenchymal stem cells (AT-MSC) and mature adipocytes from four human donors were compared, with the changes in these levels during adipogenesis analyzed. Our results show for the first time that miR-137 and miR-29b bind to the 3'UTR region of GPx7 and inhibit the expression of this enzyme at the mRNA and protein level in all the human cells tested. However, no negative correlation between miR-137 nor miR-29b level and GPx7 was observed during adipogenesis. Despite the confirmed inhibition of GPx7 expression by miR-137 and miR-29b, the action of these two molecules in adipogenesis and mature adipocytes must be accompanied by other regulators.

Oxidative-Signaling in Neural Stem Cell-Mediated Plasticity: Implications for Neurodegenerative Diseases

The adult mammalian brain is capable of generating new neurons from existing neural stem cells (NSCs) in a process called adult neurogenesis. This process, which is critical for sustaining cognition and mental health in the mature brain, can be severely hampered with ageing and different neurological disorders. Recently, it is believed that the beneficial effects of NSCs in the injured brain relies not only on their potential to differentiate and integrate into the preexisting network, but also on their secreted molecules. In fact, further insight into adult NSC function is being gained, pointing to these cells as powerful endogenous "factories" that produce and secrete a large range of bioactive molecules with therapeutic properties. Beyond anti-inflammatory, neurogenic and neurotrophic effects, NSC-derived secretome has antioxidant proprieties that prevent mitochondrial dysfunction and rescue recipient cells from oxidative damage. This is particularly important in neurodegenerative contexts, where oxidative stress and mitochondrial dysfunction play a significant role. In this review, we discuss the current knowledge and the therapeutic opportunities of NSC secretome for neurodegenerative diseases with a particular focus on mitochondria and its oxidative state.

miR-509-5p anti-infection response for mycoplasma pneumonia in sheep by targeting NF-κB pathway

MicroRNAs play a key role in Mannan-binding lectin-mediated resistance to Mycoplasma ovipneumoniae pneumonia, by regulating the translation of mRNAs of target genes, thereby regulating the immune response. Additionally, TRAF6 is a key molecule in Toll-like receptor signal transduction, which mediates inflammation and apoptosis signaling pathways and is widely involved in inflammation and immune response. While the molecular regulation mechanism has not been reported. In this study, we screened differentially expressed miRNAs and genes of Anti-infection for M. pneumonia on Sheep, through relevant bioinformatics analysis. Further, the effect of differential expression of NF-κB signaling pathway related genes on the molecular mechanism of M. pneumonia was detected. We used miRNA-mRNA integrated analysed, the target gene TRAF6 of miR-509-5p was selected. TRAF6 dual luciferase reporter vector was co-transfected into HEK 293T cells and primary sheep respiratory mucosal epithelial cells to detect changes in luciferase activity. qRT-PCR was used to analyze the effect of miR-509-5p on the expression and regulation of TRAF6 and other genes related to the NF-κB signaling pathway. The result confirmed that TRAF6 was a target gene of miR-509-5p. Compared with miR-509-5p-NC group, the luciferase activity of miR-509-5p group was significantly down-regulated (P < 0.01). Further, in sheep respiratory mucosal epithelial cells, miR-509-5p mimic could significantly down-regulate the fold change value of TRAF6 (P < 0.01). On the contrary, miR-509-5p-inhibitor up-regulated the fold change value of TRAF6 (P < 0.05). Interestingly, the expression levels of other genes were different. Among them, miR-509-5p mimic significantly up-regulated TLR4 and IRAK4 (P < 0.05), significantly down-regulated TAK1 (P < 0.05) and NF-κB (P < 0.01). miR-509-5p-inhibitor significantly up-regulated NF-κB (P < 0.05) and TAK1 (P < 0.01). miR-509-5p targets TRAF6 to affect the expression of downstream genes, which negatively regulates the NF-κB pathway, thereby affecting the inflammatory response.

Identification of the Competing Endogenous RNA Networks in Oxidative Stress Injury of Melanocytes

Competing endogenous RNAs (ceRNAs), including long noncoding RNA (lncRNA), circular RNA (circRNA), pseudogenes, synthetic miRNA inhibitors, etc. are classes of RNAs that can compete and interact with each other within an organism. There are regions in these RNAs that can be bound by messenger-RNA-interfering complementary RNA (microRNA), called microRNA response elements (MREs). These RNAs compete with each other to combine complementary microRNAs and MREs to form ceRNA regulatory mechanisms and participate in the regulation of many biological processes. The oxidative stress injury of melanocytes is one of the crucial mechanisms of vitiligo. However, it is unclear whether the ceRNA regulation mechanism is involved in the oxidative stress injury of melanocytes. The purpose of this study is to explore the changes of messenger RNA (mRNA), lncRNAs, and circRNAs in melanocytes under oxidative stress and to identify the key ceRNA regulatory networks. Compared with the normal cells, the chip detection of ceRNA expression profile showed that the expression of 491 mRNAs, 865 lncRNAs, and 1161 circRNAs were altered more than fivefold during the oxidative stress injury of melanocytes. The oxidative stress-related genes (SOD2, PTGS2, DHFR, HMOX1, FOSL1, and PARP1), cell cycle-related genes (CDK1, CCNB1, CCNA2, OIP5, and MK167), and apoptosis-related gene (BIRC5) were identified in the formation of ceRNA regulation networks with lncRNAs and circRNAs, which shares the common MREs. Further verification found that LNCV6_120941_PI430048170 or hsa_circ_0048910 might regulate the expression of SOD2 by sponging hsa-miR-4755-3p, LNCV6_119109_PI430048170, or hsa_circ_0048909 might regulate the expression of HMOX1 by sponging hsa-miR-6721-5p in the oxidative stress injury of melanocytes. In conclusion, complex changes of the ceRNA regulatory network in the oxidative stress response of melanocytes are evident. Oxidative stress may mediate melanocyte injury through the ceRNA regulation mechanism and induce the pathogenesis of vitiligo.

The role of Nrf2 in neural stem/progenitors cells: From maintaining stemness and self-renewal to promoting differentiation capability and facilitating therapeutic application in neurodegenerative disease

Neurodegenerative diseases (NDs) cause progressive loss of neurons in nervous system. NDs are categorized as acute NDs such as stroke and head injury, besides chronic NDs including Alzheimer's, Parkinson's, Huntington's diseases, Friedreich's Ataxia, Multiple Sclerosis. The exact etiology of NDs is not understood but oxidative stress, inflammation and synaptic dysfunction are main hallmarks. Oxidative stress leads to free radical attack on neural cells which contributes to protein misfolding, glia cell activation, mitochondrial dysfunction, impairment of DNA repair system and subsequently cellular death. Neural stem cells (NSCs) support adult neurogenesis in nervous system during injuries which is limited to certain regions in brain. NSCs can differentiate into the neurons, astrocytes or oligodendrocytes. Impaired neurogenesis and inadequate induction of neurogenesis are the main obstacles in treatment of NDs. Protection of neural cells from oxidative damages and supporting neurogenesis are promising strategies to treat NDs. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a transcriptional master regulator that maintains the redox homeostasis in cells by provoking expression of antioxidant, anti-inflammatory and cytoprotective genes. Nrf2 can strongly influence the NSCs function and fate determination by reducing levels of reactive oxygen species in benefit of NSC survival and neurogenesis. In this review we will summarize the role of Nrf2 in NSC function, and exogenous and endogenous therapeutic strategies in treatment of NDs.

Extracellular Vesicles Loaded miRNAs as Potential Modulators Shared Between Glioblastoma, and Parkinson's and Alzheimer's Diseases

Glioblastoma (GBM) is the deadliest brain tumor. Its poor prognosis is due to cell heterogeneity, invasiveness, and high vascularization that impede an efficient therapeutic approach. In the past few years, several molecular links connecting GBM to neurodegenerative diseases (NDDs) were identified at preclinical and clinical level. In particular, giving the increasing critical role that epigenetic alterations play in both GBM and NDDs, we deeply analyzed the role of miRNAs, small non-coding RNAs acting epigenetic modulators in several key biological processes. Specific miRNAs, transported by extracellular vesicles (EVs), act as intercellular communication signals in both diseases. In this way, miRNA-loaded EVs modulate GBM tumorigenesis, as they spread oncogenic signaling within brain parenchyma, and control the aggregation of neurotoxic protein (Tau, Aβ-amyloid peptide, and α-synuclein) in NDDs. In this review, we highlight the most promising miRNAs linking GBM and NDDs playing a significant pathogenic role in both diseases.

miR-137: A Novel Therapeutic Target for Human Glioma

MicroRNA (miR)-137 is highly expressed in the brain and plays a crucial role in the development and prognosis of glioma. In this review, we aim to summarize the latest findings regarding miR-137 in glioma cell apoptosis, proliferation, migration, invasion, angiogenesis, drug resistance, and cancer treatment. In addition, we focus on the identified miR-137 targets and pathways in the occurrence and development of glioma. Finally, future implications for the diagnostic and therapeutic potential of miR-137 in glioma were discussed.

MiRNA-137-mediated modulation of mitochondrial dynamics regulates human neural stem cell fate

The role of miRNAs in determining human neural stem cell (NSC) fate remains elusive despite their high expression in the developing nervous system. In this study, we investigate the role of miR‐137, a brain‐enriched miRNA, in determining the fate of human induced pluripotent stem cells‐derived NSCs (hiNSCs). We show that ectopic expression of miR‐137 in hiNSCs reduces proliferation and accelerates neuronal differentiation and migration. TargetScan and MicroT‐CDS predict myocyte enhancer factor‐2A (MEF2A), a transcription factor that regulates peroxisome proliferator‐activated receptor‐gamma coactivator (PGC1α) transcription, as a target of miR‐137. Using a reporter assay, we validate MEF2A as a downstream target of miR‐137. Our results indicate that reduced levels of MEF2A reduce the transcription of PGC1α, which in turn impacts mitochondrial dynamics. Notably, miR‐137 accelerates mitochondrial biogenesis in a PGC1α independent manner by upregulating nuclear factor erythroid 2 (NFE2)‐related factor 2 (NRF2) and transcription factor A of mitochondria (TFAM). In addition, miR‐137 modulates mitochondrial dynamics by inducing mitochondrial fusion and fission events, resulting in increased mitochondrial content and activation of oxidative phosphorylation (OXPHOS) and oxygen consumption rate. Pluripotency transcription factors OCT4 and SOX2 are known to have binding sites in the promoter region of miR‐137 gene. Ectopic expression of miR‐137 elevates the expression levels of OCT4 and SOX2 in hiNSCs which establishes a feed‐forward self‐regulatory loop between miR‐137 and OCT4/SOX2. Our study provides novel molecular insights into NSC fate determination by miR‐137.