MiR-21 is an Ngf-modulated microRNA that supports Ngf signaling and regulates neuronal degeneration in PC12 cells

MicroRNAs as potential biomarkers for diagnosis of schizophrenia and influence of antipsychotic treatment

ABSTRACT

Characterized by positive symptoms (such as changes in behavior or thoughts, including delusions and hallucinations), negative symptoms (such as apathy, anhedonia, and social withdrawal), and cognitive impairments, schizophrenia is a chronic, severe, and disabling mental disorder with late adolescence or early adulthood onset. Antipsychotics are the most commonly used drugs to treat schizophrenia, but those currently in use do not fully reverse all three types of symptoms characterizing this condition. Schizophrenia is frequently misdiagnosed, resulting in a delay of or inappropriate treatment. Abnormal expression of microRNAs is connected to brain development and disease and could provide novel biomarkers for the diagnosis and prognosis of schizophrenia. The recent studies reviewed included microRNA profiling in blood- and urine-based materials and nervous tissue materials. From the studies that had validated the preliminary findings, potential candidate biomarkers for schizophrenia in adults could be miR-22-3p, -30e-5p, -92a-3p, -148b-5p, -181a-3p, -181a-5p, -181b-5p, -199b-5p, -137 in whole blood, and miR-130b, -193a-3p in blood plasma. Antipsychotic treatment of schizophrenia patients was found to modulate the expression of certain microRNAs including miR-130b, -193a-3p, -132, -195, -30e, -432 in blood plasma. Further studies are warranted with adolescents and young adults having schizophrenia and consideration should be given to using animal models of the disorder to investigate the effect of suppressing or overexpressing specific microRNAs.

Nerve Growth Factor-Preconditioned Mesenchymal Stem Cell-Derived Exosome-Functionalized 3D-Printed Hierarchical Porous Scaffolds with Neuro-Promotive Properties for Enhancing Innervated Bone Regeneration

The essential role of the neural network in enhancing bone regeneration has often been overlooked in biomaterial design, leading to delayed or compromised bone healing. Engineered mesenchymal stem cells (MSCs)-derived exosomes are becoming increasingly recognized as potent cell-free agents for manipulating cellular behavior and improving therapeutic effectiveness. Herein, MSCs are stimulated with nerve growth factor (NGF) to regulate exosomal cargoes to improve neuro-promotive potential and facilitate innervated bone regeneration. In vitro cell experiments showed that the NGF-stimulated MSCs-derived exosomes (N-Exos) obviously improved the cellular function and neurotrophic effects of the neural cells, and consequently, the osteogenic potential of the osteo-reparative cells. Bioinformatic analysis by miRNA sequencing and pathway enrichment revealed that the beneficial effects of N-Exos may partly be ascribed to the NGF-elicited multicomponent exosomal miRNAs and the subsequent regulation and activation of the MAPK and PI3K-Akt signaling pathways. On this basis, N-Exos were delivered on the micropores of the 3D-printed hierarchical porous scaffold to accomplish the sustained release profile and extended bioavailability. In a rat model with a distal femoral defect, the N-Exos-functionalized hierarchical porous scaffold significantly induced neurovascular structure formation and innervated bone regeneration. This study provided a feasible strategy to modulate the functional cargoes of MSCs-derived exosomes to acquire desirable neuro-promotive and osteogenic potential. Furthermore, the developed N-Exos-functionalized hierarchical porous scaffold may represent a promising neurovascular-promotive bone reparative scaffold for clinical translation.

Possible role of miRNAs in pheochromocytoma pathology - Signaling pathways interaction

Pheochromocytoma (PCC) is a type of neuroendocrine tumor that originates from adrenal medulla or extra-adrenal chromaffin cells and results in the production of catecholamine. Paroxysmal hypertension and cardiovascular crises were among the clinical signs experienced by people with PCC. Five-year survival of advanced-stage PCC is just around 40% despite the identification of various molecular-level fundamentals implicated in these pathogenic pathways. MicroRNAs (miRNAs, miRs) are a type of short, non-coding RNA (ncRNA) that attach to the 3'-UTR of a target mRNA, causing translational inhibition or mRNA degradation. Evidence is mounting that miRNA dysregulation plays a role in the development, progression, and treatment of cancers like PCC. Hence, this study employs a comprehensive and expedited survey to elucidate the potential role of miRNAs in the development of PCC, surpassing their association with survival rates and treatment options in this particular malignancy.

Nerve Growth Factor (NGF) Encourages the Neuroinvasive Potential of Pancreatic Cancer Cells by Activating the Warburg Effect and Promoting Tumor Derived Exosomal miRNA-21 Expression

Background

It has been reported that signaling from the nerve growth factor (NGF) pathway associated with peripheral nerves is able to contribute to perineural invasion (PNI) of pancreatic cancer (PC). Nevertheless, the underlying mechanism by which NGF leads to PNI remained poorly understood.

Methods

Western blotting was employed to determine NGF level in PC and paracarcinoma tissues and in PC cell lines as well as pancreatic ductal epithelial cells. MiaPaCa-2 and CFPAC-1 cells were treated with 100 ng/ml of NGF or the NGF inhibitor Tanezumab for 24 h, CCK-8 and Transwell assays were employed to test cell proliferation, invasion, and migration, respectively. TrkA expression was knocked down in MiaPaCa-2 and dorsal root ganglion (DRG) cells treated with NGF to determine its effect on the Warburg effect. To reveal that the NGF-TrkA signaling pathway was closely associated with PC PNI, in vitro neuroinvasion model was established by using MiaPaCa-2 cells via coculturing DRG cells in Matrigel. Further, exosomes were extracted from PC cells and identified by examining the levels of specific markers for exosomes. Then RT-qPCR was applied to test miR-21-5p level in tumor derived exosomal (TDE-miR-21-5p). RIP assay was performed to validate NGF and miR-21 binding ability in MiaPaCa-2 cells. Rescue experiments were performed by using coprocessing of Tanezumab and miR-21-5p mimic on MiaPaCa-2 cells, followed by coculture with DRG cells. Subsequently, we used a model of neuroinvasion in nude mice to assess the effect of NGF in vivo on tumor nerve invasion as well as on nociceptive transmission.

Results

NGF level was preeminently higher in PC tissues and cell lines than in paracarcinoma tissues and normal pancreatic epithelial cell lines. NGF promoted MiaPaCa-2 and CFPAC-1 cell invasion and migration, while Tanezumab treatment showed the opposite results. Besides, NGF binding to TrkA receptors encouraged the intracellular Warburg effect in PC and DRG cells. TrkA blocking-up could restrain NGF induced PC cell migration and neural invasion. Mechanistically, NGF could upregulate TDE-miR-21-5p levels, and DRG cells took up TDE to activate the Warburg effect and stimulate nociceptor gene expression. miR-21-5p inhibitor could abolish the facilitative effect of NGF on PNI in MiaPaCa-2 cells. In vivo tumorigenesis experiments, Tanezumab markedly alleviated nerve invasion of PC cells as well as relieved nociceptive conduction in animal models.

Conclusions

These findings displayed that NGF/TrkA encouraged the neuroinvasive potential of PC cells by activating the Warburg effect in DRG cells through upregulation of TDE-miR-21-5p expression.

A Review of Molecular Interplay between Neurotrophins and miRNAs in Neuropsychological Disorders

Various neurotrophins (NTs), including nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4, promote cellular differentiation, survival, and maintenance, as well as synaptic plasticity, in the peripheral and central nervous system. The function of microRNAs (miRNAs) and other small non-coding RNAs, as regulators of gene expression, is pivotal for the appropriate control of cell growth and differentiation. There are positive and negative loops between NTs and miRNAs, which exert modulatory effects on different signaling pathways. The interplay between NTs and miRNAs plays a crucial role in the regulation of several physiological and pathological brain procedures. Emerging evidence suggests the diagnostic and therapeutic roles of the interactions between NTs and miRNAs in several neuropsychological disorders, including epilepsy, multiple sclerosis, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, schizophrenia, anxiety disorders, depression, post-traumatic stress disorder, bipolar disorder, and drug abuse. Here, we review current data regarding the regulatory interactions between NTs and miRNAs in neuropsychological disorders, for which novel diagnostic and/or therapeutic strategies are emerging. Targeting NTs-miRNAs interactions for diagnostic or therapeutic approaches needs to be validated by future clinical studies.

Urinary Levels of miR-491-5p and miR-592 as Potential Diagnostic Biomarkers in Female Aging Patients with OAB: A Pilot Study

Women with overactive bladder syndrome (OAB) have a lower urinary ratio of nerve growth factor (NGF) to its precursor (proNGF) compared to healthy controls. MicroRNAs related to NGF and proNGF metabolism and to their receptors may be present in urine and may possess diagnostic value. Urine and blood samples from 20 control and 20 OAB women (50–80 years) were obtained, together with validated questionnaires and other clinical parameters. The relative expression of urinary microRNAs was measured with RT-qPCR. MiR-491-5p, which negatively controls the translation of the matrix metalloproteinase-9 (MMP-9), the main enzyme degrading NGF, was significantly decreased in OAB. Similarly, miR-592, which represses p75NTR receptor synthesis, was down-regulated in OAB. Age, renal function and insulin resistance did not affect these results. ROC curves confirmed the high sensitivity of miR-491-5p and miR-592 for diagnosis. On the other hand, miRNAs involved in the expression of proNGF, of survival receptor TrkA and of markers of nerve integrity were similar between groups. The detection of miR-491-5p and miR-592 in urine could be a useful and non-invasive tool for the diagnosis of OAB syndrome in aging women.

How miRNAs Regulate Schwann Cells during Peripheral Nerve Regeneration-A Systemic Review

A growing body of studies indicate that small noncoding RNAs, especially microRNAs (miRNA), play a crucial role in response to peripheral nerve injuries. During Wallerian degeneration and regeneration processes, they orchestrate several pathways, in particular the MAPK, AKT, and EGR2 (KROX20) pathways. Certain miRNAs show specific expression profiles upon a nerve lesion correlating with the subsequent nerve regeneration stages such as dedifferentiation and with migration of Schwann cells, uptake of debris, neurite outgrowth and finally remyelination of regenerated axons. This review highlights (a) the specific expression profiles of miRNAs upon a nerve lesion and (b) how miRNAs regulate nerve regeneration by acting on distinct pathways and linked proteins. Shedding light on the role of miRNAs associated with peripheral nerve regeneration will help researchers to better understand the molecular mechanisms and deliver targets for precision medicine.

The effects of altered neurogenic microRNA levels and their involvement in the aggressiveness of periventricular glioblastoma

INTRODUCTION

Glioblastoma multiforme is the most common primary brain tumour, with the least favourable prognosis. Despite numerous studies and medical advances, it continues to be lethal, with an average life expectancy of 15 months after chemo-radiotherapy.

DEVELOPMENT

Recent research has addressed several factors associated with the diagnosis and prognosis of glioblastoma; one significant factor is tumour localisation, particularly the subventricular zone, which represents one of the most active neurogenic niches of the adult human brain. Glioblastomas in this area are generally more aggressive, resulting in unfavourable prognosis and a shorter life expectancy. Currently, the research into microRNAs (miRNA) has intensified, revealing different expression patterns under physiological and pathophysiological conditions. It has been reported that the expression levels of certain miRNAs, mainly those related to neurogenic processes, are dysregulated in oncogenic events, thus favouring gliomagenesis and greater tumour aggressiveness. This review discusses some of the most important miRNAs involved in subventricular neurogenic processes and their association with glioblastoma aggressiveness.

CONCLUSIONS

MiRNA regulation and function play an important role in the development and progression of glioblastoma; understanding the alterations of certain miRNAs involved in both differentiation and neural and glial maturation could help us to better understand the malignant characteristics of glioblastoma.

Current Therapies for Neonatal Hypoxic-Ischaemic and Infection-Sensitised Hypoxic-Ischaemic Brain Damage

Neonatal hypoxic-ischaemic brain damage is a leading cause of child mortality and morbidity, including cerebral palsy, epilepsy, and cognitive disabilities. The majority of neonatal hypoxic-ischaemic cases arise as a result of impaired cerebral perfusion to the foetus attributed to uterine, placental, or umbilical cord compromise prior to or during delivery. Bacterial infection is a factor contributing to the damage and is recorded in more than half of preterm births. Exposure to infection exacerbates neuronal hypoxic-ischaemic damage thus leading to a phenomenon called infection-sensitised hypoxic-ischaemic brain injury. Models of neonatal hypoxia-ischaemia (HI) have been developed in different animals. Both human and animal studies show that the developmental stage and the severity of the HI insult affect the selective regional vulnerability of the brain to damage, as well as the subsequent clinical manifestations. Therapeutic hypothermia (TH) is the only clinically approved treatment for neonatal HI. However, the number of HI infants needed to treat with TH for one to be saved from death or disability at age of 18-22 months, is approximately 6-7, which highlights the need for additional or alternative treatments to replace TH or increase its efficiency. In this review we discuss the mechanisms of HI injury to the immature brain and the new experimental treatments studied for neonatal HI and infection-sensitised neonatal HI.

Gypenoside XVII protects against spinal cord injury in mice by regulating the microRNA‑21‑mediated PTEN/AKT/mTOR pathway

Gypenoside XVII (GP‑17), one of the dominant active components of Gynostemma pentaphyllum, has been studied extensively and found to have a variety of pharmacological effects, including neuroprotective properties. However, the neuroprotective effects of GP‑17 against spinal cord injury (SCI), as well as its underlying mechanisms of action remain unknown. The present study aimed to investigate the effects of GP‑17 on motor recovery and histopathological changes following SCI and to elucidate the mechanisms underlying its neuroprotective effects in a mouse model of SCI. Motor recovery was evaluated using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. Spinal cord edema was detected by the wet/dry weight method. H&E staining was performed to examine the effect of GP‑17 on spinal cord damage. Inflammatory response production was assessed by ELISA. Candidate miRNAs were identified following the integrated analysis of the Gene Expression Omnibus (GEO) dataset GSE67515. Western blot analysis was also performed to detect the expression levels of associated proteins. The results revealed that GP‑17 treatment improved functional recovery, and suppressed neuronal apoptosis and the inflammatory response in the mouse model of SCI. Moreover, it was observed that miR‑21 expression was downregulated following SCI, whereas it was upregulated following the administration of GP‑17. The inhibition of miR‑21 eliminated the protective effects of GP‑17 on SCI‑induced neuronal apoptosis and the inflammatory response. In addition, phosphatase and tensin homologue (PTEN), a key molecule in the activation of the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, was identified as a target of miR‑21, and PTEN expression was downregulated by GP‑17 through miR‑21. Furthermore, the PTEN/AKT/mTOR pathway was inactivated by SCI, whereas it was re‑activated by GP‑17 through the regulation of miR‑21 in mice with SCI. On the whole, the findings of the present study suggest that GP‑17 plays a protective role in SCI via regulating the miR‑21/PTEN/AKT/mTOR pathway.

MicroRNAs: emerging driver of cancer perineural invasion

The perineural invasion (PNI), which refers to tumor cells encroaching on nerve, is a clinical feature frequently occurred in various malignant tumors, and responsible for postoperative recurrence, metastasis and decreased survival. The pathogenesis of PNI switches from 'low-resistance channel' hypothesis to 'mutual attraction' theory between peripheral nerves and tumor cells in perineural niche. Among various molecules in perineural niche, microRNA (miRNA) as an emerging modulator of PNI through generating RNA-induced silencing complex (RISC) to orchestrate oncogene and anti-oncogene has aroused a wide attention. This article systematically reviewed the role of microRNA in PNI, promising to identify new biomarkers and offer cancer therapeutic targets.

NGF and the Amyloid Precursor Protein in Alzheimer's Disease: From Molecular Players to Neuronal Circuits

Alzheimer's disease (AD), one of the most common causes of dementia in elderly people, is characterized by progressive impairment in cognitive function, early degeneration of basal forebrain cholinergic neurons (BFCNs), abnormal metabolism of the amyloid precursor protein (APP), amyloid beta-peptide (Aβ) depositions, and neurofibrillary tangles. According to the cholinergic hypothesis, dysfunction of acetylcholine-containing neurons in the basal forebrain contributes markedly to the cognitive decline observed in AD. In addition, the neurotrophic factor hypothesis posits that the loss nerve growth factor (NGF) signalling in AD may account for the vulnerability to atrophy of BFCNs and consequent impairment of cholinergic functions. Though acetylcholinesterase inhibitors provide only partial and symptomatic relief to AD patients, emerging data from in vivo magnetic resonance imaging (MRI) and positron emission tomography (PET) studies in mild cognitive impairment (MCI) and AD patients highlight the early involvement of BFCNs in MCI and the early phase of AD. These data support the cholinergic and neurotrophic hypotheses of AD and suggest new targets for AD therapy.Different mechanisms account for selective vulnerability of BFCNs to AD pathology, with regard to altered metabolism of APP and tau. In this review, we provide a general overview of the current knowledge of NGF and APP interplay, focusing on the role of APP in regulating NGF receptors trafficking/signalling and on the involvement of NGF in modulating phosphorylation of APP, which in turn controls APP intracellular trafficking and processing. Moreover, we highlight the consequences of APP interaction with p75NTR and TrkA receptor, which share the same binding site within the APP juxta-membrane domain. We underline the importance of insulin dysmetabolism in AD pathology, in the light of our recent data showing that overlapping intracellular signalling pathways stimulated by NGF or insulin can be compensatory. In particular, NGF-based signalling is able to ameliorates deficiencies in insulin signalling in the medial septum of 3×Tg-AD mice. Finally, we present an overview of NGF-regulated microRNAs (miRNAs). These small non-coding RNAs are involved in post-transcriptional regulation of gene expression , and we focus on a subset that are specifically deregulated in AD and thus potentially contribute to its pathology.

Dim Light at Night Induced Neurodegeneration and Ameliorative Effect of Curcumin

It is a well-known fact that following a proper routine light/dark or diurnal rhythm controls almost all biological processes. With the introduction of modern lighting and artificial illumination systems, continuous exposure to light at night may lead to the disruption of diurnal rhythm. However, the effect of light during the night on brain anatomy, physiology, and human body functions is less explored and poorly understood. In this study, we have evaluated the effect of exposure to dim light (5 lux) at night (dLAN) on Swiss Albino mice over a duration of three consecutive weeks. Results have revealed that exposure to dLAN led to an impairment of cognitive and non-cognitive behaviour, oxidative stress–mediated elevation of lipid peroxidation, and reduction of superoxide dismutase and catalase activity. It also led to the downregulation of hippocampal proteins (BDNF, Synapsin II and DCX) at both protein and mRNA level. Additionally, there was downregulation of CREB and SIRT1 mRNAs and neurodegeneration-associated miRNA21a-5p and miRNA34a-5p. The pyramidal and cortical neurons started showing pyknotic and chromatolysis characteristics. However, a dose of curcumin administered to the mice positively modulated these parameters in our experimental animals. We proposed the modulatory role of curcumin in addressing the deleterious effects of dLAN.

Astragalus saponin IV promotes osteogenic differentiation of bone marrow mesenchymal stem cells via miR-21/NGF/BMP2/Runx2 pathway

BACKGROUND

Astragalus saponin IV(AS- IV) extracted from tranditional Chinese medicine Radix Astragali Mongolici, which had been reported to have medicinal properties in treating several types of diseases. This study aimed at investigating the biological functions of AS-IV on bone marrow mesenchymal cells(BMSCs) differentiation, therefore, seeking for a better application of AS-IV on fracture or other orthopedic disorders.

METHODS

AS-IV was co-incubated with BMSCs in vitro to testify whether it can influence the proliferation and differentiation of BMSCs. Cell proliferation activity was detected by Cell Counting Kit-8 (CCK-8), while its differentiation promoting capibility was obtained by alkaline phosphatase (ALP) activity assay and Alizarin red S staining. Besides, differentiation protein markers of preosteoblast was detected by western blots. Neuron growth factor antagonists (NGFA) and microRNA-21 (miR-21) inhibitors were co incubated with AS-IV to search the regulatory pathways it activated in BMSCs.

RESULTS

AS-IV incubation boosted the proliferation of BMSCs, and accelerated the differentiating direction into preosteoblasts. Runx2, OPN, BMP2, OCN proteins were up regulated after AS- IV treatment. MiR-21/NGF/BMP2/Runx2 pathway can participate the biological effects of AS- IV on BMSCs.

CONCLUSION

AS- IV might be used as a therapeutic agent for bone fracture or other orthopedic disorders.

The effects of altered neurogenic microRNA levels and their involvement in the aggressiveness of periventricular glioblastoma

INTRODUCTION

Glioblastoma multiforme is the most common primary brain tumour, with the least favourable prognosis. Despite numerous studies and medical advances, it continues to be lethal, with an average life expectancy of 15 months after chemo-radiotherapy.

DEVELOPMENT

Recent research has addressed several factors associated with the diagnosis and prognosis of glioblastoma; one significant factor is tumour localisation, particularly the subventricular zone, which represents one of the most active neurogenic niches of the adult human brain. Glioblastomas in this area are generally more aggressive, resulting in unfavourable prognosis and a shorter life expectancy. Currently, the research into microRNAs (miRNA) has intensified, revealing different expression patterns under physiological and pathophysiological conditions. It has been reported that the expression levels of certain miRNAs, mainly those related to neurogenic processes, are dysregulated in oncogenic events, thus favouring gliomagenesis and greater tumour aggressiveness. This review discusses some of the most important miRNAs involved in subventricular neurogenic processes and their association with glioblastoma aggressiveness.

CONCLUSIONS

MiRNA regulation and function play an important role in the development and progression of glioblastoma; understanding the alterations of certain miRNAs involved in both differentiation and neural and glial maturation could help us to better understand the malignant characteristics of glioblastoma.

Podoplanin Gene Disruption in Mice Promotes in vivo Neural Progenitor Cells Proliferation, Selectively Impairs Dentate Gyrus Synaptic Depression and Induces Anxiety-Like Behaviors

Podoplanin (Pdpn), a brain-tumor-related glycoprotein identified in humans and animals, is endogenously expressed in several organs critical for life support such as kidney, lung, heart and brain. In the brain, Pdpn has been identified in proliferative nestin-positive adult neural progenitor cells and in neurons of the neurogenic hippocampal dentate gyrus (DG), a structure associated to anxiety, critical for learning and memory functions and severely damaged in people with Alzheimer's Disease (AD). The in vivo role of Pdpn in adult neurogenesis and anxiety-like behavior remained however unexplored. Using mice with disrupted Pdpn gene as a model organism and applying combined behavioral, molecular biological and electrophysiological assays, we here show that the absence of Pdpn selectively impairs long-term synaptic depression in the neurogenic DG without affecting the CA3-Schaffer's collateral-CA1 synapses. Pdpn deletion also enhanced the proliferative capacity of DG neural progenitor cells and diminished survival of differentiated neuronal cells in vitro. In addition, mice with podoplanin gene disruption showed increased anxiety-like behaviors in experimentally validated behavioral tests as compared to wild type littermate controls. Together, these findings broaden our knowledge on the molecular mechanisms influencing hippocampal synaptic plasticity and neurogenesis in vivo and reveal Pdpn as a novel molecular target for future studies addressing general anxiety disorder and synaptic depression-related memory dysfunctions.

Down-regulated miR-21 promotes learning-memory recovery after brain injury

BACKGROUND

MicroRNA is anendogenous non-coding single strand RNA which consists of 22 nt. It post-transcriptionally regulates gene expression and development. MicroRNA 21 plays an important role in repairing injured brain tissues. Thus, in this research, we explored the function of miR-21 in learning-memory recovery after brain injury.

METHOD

3 days old newborn SD rats were separated into three groups: Sham operation group (Sham), inflammation-sensitized hypoxic-ischemic brain injury (LPS+HI) group and miR-21 inhibitor group. 28 days later, the learning and memory capability was assayed by water maze. H&E staining and Nissl's staining were used to assay pathologic changes and TUNEL was used to assay neuron apoptosis in brain tissue.

RESULTS

Water maze assay showed that the capability of positioning navigation in the IH-HI group was worse than in the Sham group and miR-21 inhibition group, and the Sham group wass better than miR-21 group. Both of the comparisons had statistical significance (P < 0.05). H&E staining in the sham group showed that the neurons were arranged well in hippocampus. In LPS+HI group, some neurons in hippocampus had vacuolar degeneration and the neurons were not well arranged well. In the hippocampus of miR-21 inhibitor group, the neuron cell layers were decreased but the neurons were arranged better than in the LPS+HI group. Nissl's staining in LPS+HI group showed neuronal edema, neurons decreased, and Nissl's bodies decreased in the cytoplasm compared with the sham group. However, compared with the LPS+HI group, Nissl's staining in miR-21 inhibitor group showed that the neuronal edema was alleviated and neurons were better arranged. TUNEL assay showed that the apoptosis rate of LPS+HI group was higher than in the miR-21 inhibitor group and miR-21 inhibitor group was higher than the sham group.

CONCLUSION

Down-regulated miR-21 can alleviate LPS+HI injury in the brain.

MicroRNA in Brain pathology: Neurodegeneration the Other Side of the Brain Cancer

The mammalian brain is made up of billions of neurons and supporting cells (glial cells), intricately connected. Molecular perturbations often lead to neurodegeneration by progressive loss of structure and malfunction of neurons, including their death. On the other side, a combination of genetic and cellular factors in glial cells, and less frequently in neurons, drive oncogenic transformation. In both situations, microenvironmental niches influence the progression of diseases and therapeutic responses. Dynamic changes that occur in cellular transcriptomes during the progression of developmental lineages and pathogenesis are controlled through a variety of regulatory networks. These include epigenetic modifications, signaling pathways, and transcriptional and post-transcriptional mechanisms. One prominent component of the latter is small non-coding RNAs, including microRNAs, that control the vast majority of these networks including genes regulating neural stemness, differentiation, apoptosis, projection fates, migration and many others. These cellular processes are also profoundly dependent on the microenvironment, stemness niche, hypoxic microenvironment, and interactions with associated cells including endothelial and immune cells. Significantly, the brain of all other mammalian organs expresses the highest number of microRNAs, with an additional gain in expression in the early stage of neurodegeneration and loss in expression in oncogenesis. However, a mechanistic explanation of the concept of an apparent inverse correlation between the odds of cancer and neurodegenerative diseases is only weakly developed. In this review, we thus will discuss widespread de-regulation of microRNAome observed in these two major groups of brain pathologies. The deciphering of these intricacies is of importance, as therapeutic restoration of pre-pathological microRNA landscape in neurodegeneration must not lead to oncogenesis and vice versa. We thus focus on microRNAs engaged in cellular processes that are inversely regulated in these diseases. We also aim to define the difference in microRNA networks between pro-survival and pro-apoptotic signaling in the brain.

Bisphenol S Triggers the Migration and Invasion of Pheochromocytoma PC12 Cells via Estrogen-Related Receptor α

Pheochromocytoma (PCC) is a tumor of the adrenal medulla for which surgical resection is the only therapy approach. Risk factors responsible for the tumorigenesis and progression of PCC are not well illustrated. Our present study revealed that an industrial chemical, bisphenol S (BPS), can promote the migration and invasion of PCC PC12 cells, which was evidenced by the upregulation of fibronectin (FN) and matrix metalloproteinases (MMP-2 and MMP-9). The inhibitor of estrogen-related receptor α (ERRα), while not estrogen receptor α/β (ERα/β) or G protein-coupled estrogen receptor (GPER), can attenuate BPS-induced cell migration. Mechanically, BPS can increase the binding between ERRα and promoter of FN1 and then induce the expression of FN in PC12 cells. Further, BPS can induce the expression of miR-10b in PC12 cells via ERRα. The upregulated miR-10b inhibited the expression of KLF4, which can suppress the migration and invasion of cancer cells. BPS can trigger the mRNA and protein expression of ERRα in PC12 cells via a time-dependent manner. Collectively, our study revealed that nanomolar BPS can trigger the migration and invasion of PC12 cells via activation and upregulation of ERRα.

Emerging role of MicroRNAs in peripheral nerve system

Peripheral nerve injury is one of the most common clinical diseases. Although the regeneration of the peripheral nerve is better than that of the nerves of the central nervous system, because of its growth rate restrictions after damage. Hence, the outcome of repair after injury is not favorable. Small RNA, a type of non-coding RNA, has recently been gaining attention in neural injury. It is widely distributed in the nervous system in vivo and a significant change in the expression of small RNAs has been observed in a neural injury model. This suggests that MicroRNAs (miRNAs) may serve as a potential target for resolving the challenges of peripheral nerve repair. This review summarizes the current challenges in peripheral nerve injury repair, systematically expounds the mechanism of miRNAs in the process of nerve injury and repair and attempts to determine the possible treatment of peripheral nerve injury.

MiR-21 attenuates apoptosis-triggered by amyloid-β via modulating PDCD4/ PI3K/AKT/GSK-3β pathway in SH-SY5Y cells

Alzheimer's disease (AD) remains the most common neurodegenerative disease with amyloid beta (Aβ) formatted and accumulated. Recently, microRNAs have been identified as significant regulators in neurogenesis of the central nervous system (CNS). However, the biological role of miR-21 in AD remains unclear. The purpose of our study was to investigate the mechanism of miR-21 in AD. AD model was established using 20 μM Aβ_1-42 in SH-SY5Y cells. Aβ_1-42 can induce cell apoptosis via increasing Bax and decreasing Bcl-2 protein levels. Meanwhile, we observed that miR-21 was remarkably elevated by indicated Aβ_1-42 in vitro. Subsequently, miR-21 mimics were transfected into SH-SY5Y cells and it was found that miR-21 can inhibit cell apoptosis induced by Aβ_1-42. Programmed cell death protein 4 (PDCD4), an important tumor suppressor in various cancers has been reported to prevent AKT activation. The phosphatidylinositol 3-kinase (PI3K)/AKT/GSK-3β pathway can release a survival signal to protect from multiple injuries. Interestingly, it was found that PDCD4 was involved in miR-21-repressed cell apoptosis in AD models. miR-21 mimics can increase the PI3K, AKT and GSK-3β activity while PDCD4 ovexexpression inhibited their activity respectively. Moreover, knockdown of PDCD4 can rescue PI3K/AKT/GSK-3β pathway in SH-SY5Y cells. Taken these together, it was suggested by our data that miR-21 can exert protective roles in AD, which might be dependent on PDCD4/PI3K/AKT/GSK-3β signaling pathway in vitro.

A novel information diffusion method based on network consistency for identifying disease related microRNAs

The abnormal expression of miRNAs is directly related to the development of human diseases. Predicting the potential candidate miRNAs associated with diseases can contribute to the detection, diagnosis, treatment and prevention of human complex diseases. The effective inference of the calculation method of the relationship between miRNAs and diseases is an effective supplement to biological experiments. It is of great help in the prevention, treatment and prognosis of complex diseases. This paper proposes a novel information diffusion method based on network consistency (IDNC) for identifying disease related microRNAs. The model first synthesizes the miRNA family information and the miRNA function similarity to reconstruct the miRNA network, and reconstruct the disease network by using the known disease and miRNA-related information and the semantic score between diseases. Then the global similarity of the two networks is obtained by using the Laplacian score of graphs. The global similarity score is a measure of the similarity between diseases and miRNAs. The disease–miRNA relation network was reconstructed by integrating the global similarity relation. The network consistency diffusion seed is then obtained by combining the global similarity network with the reconstructed disease–miRNA association network. Thereafter, the stable diffusion spectrum is generated as the prediction score by using the restarted random walk algorithm. The AUC value obtained by performing the LOOCV in the gold benchmark dataset is 0.8814. The AUC value obtained by performing the LOOCV in the predictive dataset is 0.9512. Compared with other frontier methods, our method has higher accuracy, which is further illustrated by case studies of breast neoplasms and colon neoplasms to prove that IDNC is valuable.

The abnormal expression of miRNAs is directly related to the development of human diseases.

Prediction of potential drivers connecting different dysfunctional levels in lung adenocarcinoma via a protein-protein interaction network

Lung cancer is a serious disease that threatens an affected individual's life. Its pathogenesis has not yet to be fully described, thereby impeding the development of effective treatments and preventive measures. "Cancer driver" theory considers that tumor initiation can be associated with a number of specific mutations in genes called cancer driver genes. Four omics levels, namely, (1) methylation, (2) microRNA, (3) mutation, and (4) mRNA levels, are utilized to cluster cancer driver genes. In this study, the known dysfunctional genes of these four levels were used to identify novel driver genes of lung adenocarcinoma, a subtype of lung cancer. These genes could contribute to the initiation and progression of lung adenocarcinoma in at least two levels. First, random walk with restart algorithm was performed on a protein-protein interaction (PPI) network constructed with PPI information in STRING by using known dysfunctional genes as seed nodes for each level, thereby yielding four groups of possible genes. Second, these genes were further evaluated in a test strategy to exclude false positives and select the most important ones. Finally, after conducting an intersection operation in any two groups of genes, we obtained several inferred driver genes that contributed to the initiation of lung adenocarcinoma in at least two omics levels. Several genes from these groups could be confirmed according to recently published studies. The inferred genes reported in this study were also different from those described in a previous study, suggesting that they can be used as essential supplementary data for investigations on the initiation of lung adenocarcinoma. This article is part of a Special Issue entitled: Accelerating Precision Medicine through Genetic and Genomic Big Data Analysis edited by Yudong Cai & Tao Huang.

MicroRNA-21: Expression in oligodendrocytes and correlation with low myelin mRNAs in depression and alcoholism

MiR-21 is a microRNA implicated in cancer, development, and cardiovascular diseases and expressed in the central nervous system (CNS), especially after injury. However, the cellular expression of miR-21 in the adult CNS has not been clearly established either in mice or human subjects, while its alteration in psychiatric disorders is unknown. MiR-21 expression was characterized in reporter mice expressing β-galactosidase (LacZ) under the endogenous miR-21 promoter (miR-21/LacZ). Brain co-localization of miR-21/LacZ with specific neural markers was examined by double immunofluorescence in reporter mice, while extent of immunostaining for myelin basic protein and PDGFRα was determined in miR-21 knockout and wild-type mice. Levels of miR-21, and mRNAs of selected miR-21 targets, miR-21 regulator STAT3 and myelin-related proteins were measured by qRT-PCR in the white matter (WM) adjacent to the left postmortem orbitofrontal cortex (OFC) of human subjects with major depressive disorder (MDD), alcoholism, comorbid MDD plus alcoholism (MDA) and non-psychiatric control subjects. MiR-21/LacZ was highly expressed in cell bodies of WM and myelinated portions of gray matter (GM). Labeled cell bodies were identified as oligodendrocytes, while miR-21/LacZ was barely detectable in other cell types. MiR-21, as well as the mRNAs of several myelin-related proteins, were reduced in the WM of subjects with MDD and alcoholism. MiR-21 positively correlated with mRNA of myelin-related proteins and astrocytic GFAP. High expression of miR-21 in adult oligodendrocytes and the correlation of miR-21 decrease with mRNA of some myelin proteins, regulator STAT3, and oligodendrocyte-related transcription factors suggest an involvement of miR-21 in WM alterations in depression and alcoholism.

Intermittent hypoxia caused cognitive dysfunction relate to miRNAs dysregulation in hippocampus

Intermittent hypoxia (IH) is a characteristic pathophysiological change of obstructive sleep apnea (OSA), a commonly diagnosed chronic sleep disorder. With the process of OSA, patients will suffer from the nervous system damage and appear to multiple cognitive dysfunction. The mechanism that how IH causes cognitive impairment is still unknown. Both control and experimental rats were placed in conditions absence and presence of intermittent hypoxia (IH) for 8h a day for a week, two weeks and four weeks, and then followed by behavioral assessments with Morris Water Maze (MWM) test. The results showed that the escape latency of the tested animals to IH significantly increased the escape latency on the last four training days in comparison to the control group. Consistent with this, the expressions of apoptosis/anti-apoptosis proteins were both changed in the hippocampus. Then we utilized the miRNA microarray assay to investigate the level of miRNA expression in rat hippocampus which suffered from intermittent hypoxia. It is noteworthy that the expressions of miR-26b and miR-207 were consistently dysregulated in all the experimental groups post IH. And we utilized qRT-PCR methods to verify the microarray results. Our results showed that microarray based analysis of microRNA expression in rat hippocampus after IH has shown that some microRNAs such as miR-26b and miR-207 could be involved in the OSA-induced cognitive impairments.

Extraction and separation of lactate dehydrogenase inhibitors from Poria cocos (Schw.) Wolf based on a hyphenated technique and in vitro methods

Stroke is one of the most common diseases worldwide. Lactate dehydrogenase inhibitors are widely used in the treatment of ischemic stroke, with natural products considered a promising source of lactate dehydrogenase inhibitors. In this study, ultrafiltration liquid chromatography coupled with mass spectrometry was used for the screening and identification of lactate dehydrogenase inhibitors from Poria cocos. Five lactate dehydrogenase inhibitors were selected: dehydropachymic acid, pachymic acid, dehydrotrametenolic acid, trametenolic acid, and eburicoic acid. The inhibitors were extracted and isolated with purities of 96.75, 98.15, 97.25, 95.46, and 94.88%, respectively, by using a new "hyphenated" strategy of microwave-assisted extraction coupled with counter-current chromatography and centrifugal partition chromatography by a two-phase solvent system of n-hexane/ethyl acetate/ethanol/water at the volume ratio 0.965:1.000:0.936:0.826 v/v/v/v. The bioactivity of the isolated compounds was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay in PC12 cells. The results also showed that the hyphenated technique of microwave-assisted extraction coupled with counter-current chromatography and centrifugal partition chromatography was an efficient method for the continuous extraction and online isolation of chemical constituents from medicinal herbs. Furthermore, the research route based on the activity screening, extraction, separation, and activity verification of the compounds offered advantages of efficiency, orientation, and objectivity.

Role of Nerve Growth Factor (NGF) and miRNAs in Epithelial Ovarian Cancer

Ovarian cancer is the eighth most common cancer in women worldwide, and epithelial ovarian cancer (EOC) represents 90% of cases. Nerve growth factor (NGF) and its high affinity receptor tyrosine kinase A receptor (TRKA) have been associated with the development of several types of cancer, including EOC; both NGF and TRKA levels are elevated in this pathology. EOC presents high angiogenesis and several molecules have been reported to induce this process. NGF increases angiogenesis through its TRKA receptor on endothelial cells, and by indirectly inducing vascular endothelial growth factor expression. Other molecules controlled by NGF include ciclooxigenase-2, disintegrin and metalloproteinase domain-containing protein 17 (ADAM17) and calreticulin (CRT), proteins involved in crucial processes needed for EOC progression. These molecules could be modified through microRNA regulation, which could be regulated by NGF. MicroRNAs are the widest family of non-coding RNAs; they bind to 3'-UTR of mRNAs to inhibit their translation, to deadenilate or to degraded them. In EOC, a deregulation in microRNA expression has been described, including alterations of miR-200 family, cluster-17-92, and miR-23b, among others. Since the NGF-microRNA relationship in pathologies has not been studied, this review proposes that some microRNAs could be associated with NGF/TRKA activation, modifying protein levels needed for EOC progression.

A preliminary analysis of microRNA-21 expression alteration after antipsychotic treatment in patients with schizophrenia

Schizophrenia is a severe and debilitating psychiatric disorder of unknown etiology, and its diagnosis is essentially based on clinical symptoms. Despite growing evidence on the relation of altered expression of miRNAs and schizophrenia, most patients with schizophrenia usually had an extensive antipsychotic treatment history before miRNA expression profile analysis, and the pharmacological effects on miRNA expression are largely unknown. To overcome these impediments, miRNA microarray analysis was performed in peripheral blood mononuclear cells (PBMCs) obtained from patients with schizophrenia who were not on antipsychotic medication and healthy controls. Then, using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR), we verified the top 10 miRNAs with the highest fold-change values from microarray analysis in 82 patients with schizophrenia and 43 healthy controls, and nine miRNAs demonstrated significant differences in expression levels. Finally, we compared these nine miRNA profiles before and after antipsychotic treatment. Our results revealed that serum miR-21 expression decreased strikingly in patients after antipsychotic treatment. The change of miR-21 expression was negatively correlated with improvement of positive, general psychopathology, and aggressiveness symptoms. This study preliminarily analyzed the possible changes in circulating miRNAs expression in response to antipsychotic medication for schizophrenia, and the molecular mechanisms of this needs to be further explored.

Bladder overactivity involves overexpression of MicroRNA 132 and nerve growth factor

AIM

Here, we assessed the expression of non-protein coding microRNAs (miRs), nerve growth factor and inflammatory molecules in the rat model of acetic acid induced bladder overactivity.

MAIN METHODS

Under isoflurane anesthesia, adult female Sprague-Dawley rats were instilled for 30min with either saline or NGF antisense oligonucleotide complexed with liposomes. 24h later, treated rats were exposed to either intravesical infusion of saline or saline containing 0.25% acetic acid at the rate of 0.04mL/min for 2h under urethane anesthesia (1g/kg; s.c). After CMG, bladder was harvested to study expression of NGF, cytokines and 8 specific miRNAs involved in bladder dysfunctions. The role of miR-132 in bladder overactivity was independently assessed through bladder wall transfection of plasmid encoding miR-132.

KEY FINDINGS

NGF overexpression in bladder overactivity was associated with ~2-fold upregulation and downregulation of miR-132 and miR-221, respectively. Pretreatment with NGF antisense restored the expression of miR-221 and miR-132 to control levels and also reduced the expression of NGF and cytokines (MCP-1 and sICAM-1). There was insignificant alteration in the expression of miR-199a-5p, and expression of, miR-210, miR-212, miR-155, miR-134 and miR-206 remained similar across the experimental groups. Bladder wall transfection of miR-132 plasmid in absence of acetic acid exposure was able to independently induce bladder overactivity, bladder hypertrophy and upregulate the expression of NGF and other cytokines.

SIGNIFICANCE

Overall, our work sheds light on the role of miR-132 in bladder overactivity, bladder hypertrophy, NGF signaling and expression of inflammatory mediators. Findings demonstrate that aberrant expression of NGF and miR-132 is involved in voiding dysfunctions.

Differentiation Induces Dramatic Changes in miRNA Profile, Where Loss of Dicer Diverts Differentiating SH-SY5Y Cells Toward Senescence

MicroRNAs (miRNAs) are generated by endonuclease activity of Dicer, which also helps in loading of miRNAs to their target sequences. SH-SY5Y, a human neuroblastoma and a cellular model of neurodevelopment, consistently expresses genes related to neurodegenerative disorders at different biological levels (DNA, RNA, and proteins). Using SH-SY5Y cells, we have studied the role of Dicer and miRNAs in neuronal differentiation and explored involvement of P53, a master regulator of gene expression in differentiation-induced induction of miRNAs. Knocking down Dicer gene induced senescence in differentiating SH-SY5Y cells, which indicate the essential role of Dicer in brain development. Differentiation of SH-SY5Y cells by retinoic acid (RA) or RA + brain-derived neurotrophic factor (BDNF) induced dramatic changes in global miRNA expression. Fully differentiated SH-SY5Y cells (5-day RA followed by 3-day BDNF) significantly (p < 0.05 and atleast >3-fold change) upregulated and downregulated the expression of 77 and 17 miRNAs, respectively. Maximum increase was observed in the expression of miR-193-5p, miR-199a-5p, miR-192, miR-145, miR-28-5p, miR-29b, and miR-222 after RA exposure and miR-193-5p, miR-146a, miR-21, miR-199a-5p, miR-153, miR-29b, and miR-222 after RA + BDNF exposure in SH-SY5Y cells. Exploring the role of P53 in differentiating SH-SY5Y cells, we have observed that induction of miR-222, miR-192, and miR-145 is P53 dependent and expression of miR-193a-5p, miR-199a-5p, miR-146a, miR-21, miR-153, and miR-29b is P53 independent. In conclusion, decreased Dicer level enforces differentiating cells to senescence, and differentiating SH-SY5Y cells needs increased expression of P53 to cope up with changes in protein levels of mature neurons.

Traumatic brain injury increases levels of miR-21 in extracellular vesicles: implications for neuroinflammation

Traumatic brain injury (TBI) is an important health concern and effective treatment strategies remain elusive. Understanding the complex multicellular response to TBI may provide new avenues for intervention. In the context of TBI, cell–cell communication is critical. One relatively unexplored form of cell–cell communication in TBI is extracellular vesicles (EVs). These membrane‐bound vesicles can carry many different types of cargo between cells. Recently, miRNA in EVs have been shown to mediate neuroinflammation and neuronal injury. To explore the role of EV‐associated miRNA in TBI, we isolated EVs from the brain of injured mice and controls, purified RNA from brain EVs, and performed miRNA sequencing. We found that the expression of miR‐212 decreased, while miR‐21, miR‐146, miR‐7a, and miR‐7b were significantly increased with injury, with miR‐21 showing the largest change between conditions. The expression of miR‐21 in the brain was primarily localized to neurons near the lesion site. Interestingly, adjacent to these miR‐21‐expressing neurons were activated microglia. The concurrent increase in miR‐21 in EVs with the elevation of miR‐21 in neurons, suggests that miR‐21 is secreted from neurons as potential EV cargo. Thus, this study reveals a new potential mechanism of cell–cell communication not previously described in TBI.

An Antagomir to MicroRNA-106b-5p Ameliorates Cerebral Ischemia and Reperfusion Injury in Rats Via Inhibiting Apoptosis and Oxidative Stress

We previously observed that microRNA miR-106b-5p significantly increased in serum of patients with acute ischemic stroke. The present study was to determine whether miR-106b-5p antagomir can protect against cerebral ischemia/reperfusion (I/R) injury and elucidate its underlying mechanisms. Middle cerebral artery occlusion (MCAO) was operated on male Sprague Dawley rats. MiR-106b-5p antagomir significantly decreased neurological deficit scores, infarct volumes, and neuronal injury. Furthermore, miR-106b-5p antagomir markedly reduced malondialdehyde (MDA) content, restored superoxide dismutase (SOD) activity, increased the expression of myeloid cell leukemia-1 (Mcl-1) and B cell lymphoma-2 (Bcl-2), and decreased the expression of Bax in the ischemic cortex. In PC12 cells, miR-106b-5p inhibitor increased the Mcl-1 and Bcl-2 expression, which provided protection against glutamate-induced apoptosis and oxidative damage, as evidenced by decreased lactate dehydrogenase (LDH) release, and enhanced SOD activity. Notably, luciferase reported assay proved Mcl-1 was the target gene of miR-106b-5p. In conclusion, our data indicates that the neuroprotective effects of miR-106b-5p antagomir on cerebral I/R injury are associated with its inhibition of apoptosis and oxidative stress, suggesting a potential therapeutic target for ischemic stroke.

Elevated serum miR-93, miR-191, and miR-499 are noninvasive biomarkers for the presence and progression of traumatic brain injury

The levels of miR-93, miR-191, and miR-499 have been reported to be up-regulated in the tissues of experimental traumatic brain injury (TBI) rat models. However, the clinical diagnostic and prognostic values of the serum signatures of these 3 miRNAs in TBI remain unclear. The purpose of this study was to determine the expression levels of these 3 microRNAs (miRNAs) in the sera of TBI patients and to evaluate their relationships with the severity and clinical outcome of TBI. The serum levels of these miRNAs were assessed in TBI patients (n = 76) and healthy controls (n = 38) by quantitative reverse-transcription PCR. The severities and clinical outcomes of the TBI patients were evaluated with the Glasgow coma scale and the Glasgow outcome scale. The serum miR-93, miR-191, and miR-499 levels were significantly increased in the TBI patients compared with the controls at all examined time points, and these levels were significantly higher in the patients with severe TBI than in those with moderate or mild TBI (p < 0.05). The serum miR-93, miR-191, and miR-499 levels were significantly higher in the patients with a poor outcome than in those with a good outcome (p < 0.05). The AUCs of miR-93, miR-191, and miR-499 for distinguishing the TBI patients from the healthy controls were 1.000 (p < 0.001), 0.727 (p < 0.001) and 0.801 (p < 0.001), respectively. Interestingly, the AUCs of miR-93, miR-191, and miR-499 for distinguishing the mild TBI patients from the healthy controls were 1.000 (p < 0.001), 0.742 (p < 0.001) and 0.819 (p < 0.001), respectively. Taken together, these results indicate that miR-93, miR-191, and miR-499 are potentially valuable indicators of the diagnosis, severity, and prognosis of TBI. Our study showed that the serum levels of miR-93, miR-191, and miR-499 are all increased in traumatic brain injury (TBI) patients. Their serum levels are associated with TBI severity and outcome, which suggest that these miRNAs play important roles in the pathogenesis and progression of TBI. We think these findings should provide a new strategy for the diagnostic, prognostic, and treatment of TBI.

MiR-207/352 regulate lysosomal-associated membrane proteins and enzymes following ischemic stroke

The role of microRNAs (miRNAs) in lysosome-mediated neuronal death and survival following ischemic stroke remains unknown. Herein, using miRNA and mRNA gene expression profiling microarrays, we identified the differentially expressed 24 miRNAs and 494 genes in the cortical peri-infarct area, respectively. Integrating the miRNA targets and mRNA expression profiles, we found 47 genes of miRNA targets, including lysosomal-associated membrane protein 2 (LAMP2), Hexb, Bcl2, etc. MiR-207 and miR-352 were mainly downregulated after ischemic stroke, followed by a slight return to baseline during post-middle cerebral artery occlusion (MCAO) 1d to 7d. Furthermore, the luciferase reporter assay demonstrated that LAMP2 and Hexb were the direct targets of miR-207 and miR-352, respectively. After lateral ventricle injection with miR-207 agonist mimics, the neurological deficit scores and infarct volumes were attenuated, and the structure of mitochondria ridges was improved. In addition, miR-207 mimics could reduce the number of cellular lysosome and autophagosome, whereas increase the number of autophagic vacuoles, indicating miR-207 might affect the latter part of lysosomal-autophagy pathway and mitochondria-induced apoptosis. These results suggested that miR-207 and miR-352 were involved in lysosomal pathway for mediating ischemic injury and spontaneous recovery. MiR-207 mimics as potential target drugs could protect against autophagic cell death after ischemic stroke.

Association of miR-193b down-regulation and miR-196a up-regulation with clinicopathological features and prognosis in gastric cancer

Dysregulated expression of microRNAs (miRNAs) has been shown to be closely associated with tumor development, progression, and carcinogenesis. However, their clinical implications for gastric cancer remain elusive. To investigate the hypothesis that genome-wide alternations of miRNAs differentiate gastric cancer tissues from those matched adjacent non-tumor tissues (ANTTs), miRNA arrays were employed to examine miRNA expression profiles for the 5-pair discovery stage, and the quantitative real-time polymerase chain reaction (qRT- PCR) was applied to validate candidate miRNAs for 48-pair validation stage. Furthermore, the relationship between altered miRNA and clinicopathological features and prognosis of gastric cancer was explored. Among a total of 1,146 miRNAs analyzed, 16 miRNAs were found to be significantly different expressed in tissues from gastric cancer compared to ANTTs (p<0.05). qRT-PCR further confirmed the variation in expression of miR-193b and miR-196a in the validation stage. Down-expression of miR-193b was significantly correlated with Lauren type, differentiation, UICC stage, invasion, and metastasis of gastric cancer (p<0.05), while over-expression of miR-196a was significantly associated with poor differentiation (p=0.022). Moreover, binary logistic regression analysis demonstrated that the UICC stage was a significant risk factor for down-expression of miR-193b (adjusted OR=8.69; 95%CI=1.06-56.91; p=0.043). Additionally, Kaplan-Meier survival curves indicated that patients with a high fold-change of down-regulated miR-193b had a significantly shorter survival time (n=19; median survival=29 months) compared to patients with a low fold-change of down-regulated miR-193b (n=29; median survival=54 months) (p=0.001). Overall survival time of patients with a low fold-change of up-regulated miR- 196a (n=27; median survival=52 months) was significantly longer than that of patients with a high fold-change of up-regulated miR-196a (n=21; median survival=46 months) (p=0.003). Hence, miR-193b and miR-196a may be applied as novel and promising prognostic markers in gastric cancer.

MicroRNA-29c/PTEN pathway is involved in mice brain development and modulates neurite outgrowth in PC12 cells

Growing evidence indicates that microRNAs (miRNAs) are important mediators of brain development and neurite growth. However, the affected signaling mechanisms are not clearly clarified. In the present study, we confirm that miR-29c is expressed during mice brain development and increases neurite outgrowth via decreasing PTEN expression. We first screen the picked-out miR-29c up-regulated in PC12 cells induced by nerve growth factor (NGF). In silico analysis of possible miR-29c targets, VEGFA, MAPK3, PDGFB, and PTEN mRNA are proposed as relatively likely putative binding sites for miR-29c. Subsequently, we detect that miR-29c is involved in brain development and has a negative relationship with the expression of PTEN. Then, using luciferase reporter assay,we demonstrate that miR-29c could directly target to the 3'-UTR of PTEN mRNA and result in down-expression of PTEN. By infecting PC12 cells with lentiviral pLKO-miR-29c or control, we also find that increasing levels of miR-29c markedly increase Akt phosphorylation level, and thus, promote neurite outgrowth of PC12 cells. Together, our results identify that miR-29c is required for mice brain development and modulates neurite outgrowth in PC12 cells via targeting PTEN and has a promising therapeutic target for neural disease.

MicroRNA Profiling Response to Acupuncture Therapy in Spontaneously Hypertensive Rats

MicroRNAs (miRNAs) are a group of endogenous noncoding RNAs that play important roles in many biological processes. This study aimed to check if miRNAs were involved in the response to acupuncture in rats. Microarray analysis was performed to compare the miRNA expression profiles of medulla in spontaneously hypertensive rats (SHRs) treated with or without acupuncture. Our microarray analysis identified 222 differentially expressed miRNAs in the medulla of SHRs treated with acupuncture at taichong acupoint. Among these miRNAs, 23 miRNAs with a significant difference were found in acupuncture-treated SHRs compared to untreated rats. These 23 miRNAs could regulate 2963 target genes which were enriched in at least 14 pathways based on our bioinformatic analysis. miRNA-339, miR-223, and miR-145 were downregulated in the medulla of SHRs compared to normotensive rats. Notably, these miRNAs were upregulated to basal levels in the medulla of SHRs treated with acupuncture at taichong in comparison with SHRs receiving acupuncture at nonacupoint group or SHRs without any treatment. Our findings have revealed significant changes of a panel of selective miRNAs in hypertensive rats treated at taichong acupoint. These data provide insights into how acupuncture elicits beneficial effects on hypertension.

Altered microRNA Expression in Peripheral Blood Mononuclear Cells from Young Patients with Schizophrenia

Schizophrenia (SZ) is a debilitating psychotic disorder of unknown etiology, and the diagnosis is essentially based on clinical symptoms. So it is urgent to find an objective and feasible clinical diagnostic index for SZ. MicroRNA array was performed in peripheral blood mononuclear cells (PBMCs) obtained from young SZ patients and gender-, age-, and ethnicity-matched healthy controls. Then, real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to verify the top 10 microRNAs (miRNAs) with the highest fold change values in 55 SZ patients and 28 healthy controls, and 9 miRNAs demonstrate significant differences in expression levels (P < 0.01). Receiver operating characteristic (ROC) curve analysis showed that the combining area under the ROC curve (AUC) of the nine miRNAs was 0.973 (95 % confidence interval (CI): 0.945-1.000). miRNA target gene prediction and functional annotation analysis showed that there were significant enrichments in several gene ontology (GO) biological process and Kyoto encyclopedia of genes and genomes (KEGG) pathways associated with nervous system and brain functions, suggesting that the differentially expressed miRNAs may be involved in mechanism of SZ. We conclude that altered expression of miRNAs in PMBCs might be involved in young SZ pathogenesis and may serve as noninvasive biomarker for SZ diagnosis.

MicroRNA-29A/PTEN pathway modulates neurite outgrowth in PC12 cells

PTEN serves as an intrinsic brake on neurite outgrowth, but the regulatory mechanism that governs its action is not clear. In the present study, miR-29a was found to increase neurite outgrowth by decreasing PTEN expression. Results showed that miR-92a-1, miR-29a, miR-92b, and miR-29c expression levels increased during nerve growth factor (NGF)-induced differentiation of PC12 cells. Based on in silico analysis of possible miR-29a targets, PTEN mRNA may be a binding site for miR-29a. A protein expression assay and luciferase reporter assay showed that miR-29a could directly target the 3'-UTRs (untranslated regions) of PTEN mRNA and down-regulate the expression of PTEN. PC12 cells infected with lentiviral pLKO-miR-29a showed far higher levels of miR-29a and Akt phosphorylation level than those infected with control. This promoted neurite outgrowth of PC12 cells. Collectively, these results indicate that miR-29a is an important regulator of neurite outgrowth via targeting PTEN and that it may be a promising therapeutic target for neural disease.

Regulatory networks between neurotrophins and miRNAs in brain diseases and cancers

Neurotrophins are involved in many physiological and pathological processes in the nervous system. They regulate and modify signal transduction, transcription and translation in neurons. It is recently demonstrated that the neurotrophin expression is regulated by microRNAs (miRNAs), changing our views on neurotrophins and miRNAs. Generally, miRNAs regulate neurotrophins and their receptors in at least two ways: (1) miRNAs bind directly to the 3′ untranslated region (UTR) of isoform-specific mRNAs and post-transcriptionally regulate their expression; (2) miRNAs bind to the 3′ UTR of the regulatory factors of neurotrophins and regulate their expression. On the other hand, neurotrophins can regulate miRNAs. The results of BNDF research show that neurotrophins regulate miRNAs in at least three ways: (1) ERK stimulation enhances the activation of TRBP (HIV-1 TAR RNA-binding protein) and Dicer, leading to the upregulation of miRNA biogenesis; (2) ERK-dependent upregulation of Lin28a (RNA-binding proteins) blocks select miRNA biogenesis; (3) transcriptional regulation of miRNA expression through activation of transcription factors, including CREB and NF-κB. These regulatory processes integrate positive and negative regulatory loops in neurotrophin and miRNA signaling pathways, and also expand the function of neurotrophins and miRNAs. In this review, we summarize the current knowledge of the regulatory networks between neurotrophins and miRNAs in brain diseases and cancers, for which novel cutting edge therapeutic, delivery and diagnostic approaches are emerging.

MicroRNA-1 in Cardiac Diseases and Cancers

MicroRNAs (miRs) are endogenous ≈22-nt non-coding RNAs that participate in the regulation of gene expression at post-transcriptional level. MiR-1 is one of the muscle-specific miRs, aberrant expression of miR-1 plays important roles in many physiological and pathological processes. In this review, we focus on the recent studies about miR-1 in cardiac diseases and cancers. The findings indicate that miR-1 may be a novel, important biomarker, and a potential therapeutic target in cardiac diseases and cancers.

miR-21 is a negative modulator of T-cell activation

microRNAs (miRNAs) are a class of small non-coding RNAs acting as post-transcriptional regulators of gene expression and play fundamental roles in regulating immune response and autoimmunity. We show that memory T-lymphocytes express higher levels of miR-21 compared to naïve T-lymphocytes and that miR-21 expression is induced upon TCR engagement of naïve T-cells. We identify bona fide miR-21 targets by direct immuno-purification and profiling of AGO2-associated mRNAs in Jurkat cells over-expressing miR-21. Our analysis shows that, in T-lymphocytes, miR-21 targets genes are involved in signal transduction. Coherently, TCR signalling is dampened upon miR-21 over-expression in Jurkat cells, resulting in lower ERK phosphorylation, AP-1 activation and CD69 expression. Primary human lymphocytes in which we impaired miR-21 activity, display IFN-γ production enhancement and stronger activation in response to TCR engagement as assessed by CD69, OX40, CD25 and CD127 analysis. By intracellular staining of the endogenous protein in primary T-lymphocytes we validate three key regulators of lymphocyte activation as novel miR-21 targets. Our results highlight an unexpected function of miR-21 as a negative modulator of signal transduction downstream of TCR in T-lymphocytes.

Regulatory effects of intermittent noxious stimulation on spinal cord injury-sensitive microRNAs and their presumptive targets following spinal cord contusion

Uncontrollable nociceptive stimulation adversely affects recovery in spinally contused rats. Spinal cord injury (SCI) results in altered microRNA (miRNA) expression both at, and distal to the lesion site. We hypothesized that uncontrollable nociception further influences SCI-sensitive miRNAs and associated gene targets, potentially explaining the progression of maladaptive plasticity. Our data validated previously described sensitivity of miRNAs to SCI alone. Moreover, following SCI, intermittent noxious stimulation decreased expression of miR124 in dorsal spinal cord 24 h after stimulation and increased expression of miR129-2 in dorsal, and miR1 in ventral spinal cord at 7 days. We also found that brain-derived neurotrophic factor (BDNF) mRNA expression was significantly down-regulated 1 day after SCI alone, and significantly more so, after SCI followed by tailshock. Insulin-like growth factor-1 (IGF-1) mRNA expression was significantly increased at both 1 and 7 days post-SCI, and significantly more so, 7 days post-SCI with shock. MiR1 expression was positively and significantly correlated with IGF-1, but not BDNF mRNA expression. Further, stepwise linear regression analysis indicated that a significant proportion of the changes in BDNF and IGF-1 mRNA expression were explained by variance in two groups of miRNAs, implying co-regulation. Collectively, these data show that uncontrollable nociception which activates sensorimotor circuits distal to the injury site, influences SCI-miRNAs and target mRNAs within the lesion site. SCI-sensitive miRNAs may well mediate adverse consequences of uncontrolled sensorimotor activation on functional recovery. However, their sensitivity to distal sensory input also implicates these miRNAs as candidate targets for the management of SCI and neuropathic pain.