The role of miR-182 in regulating pineal CLOCK expression after hypoxia-ischemia brain injury in neonatal rats

Neuroprotective effects of miRNA-326 knockout in neonatal hypoxic-ischemic brain damage mice via the δ-opioid receptor

Hypoxic-ischemic brain damage (HIBD) in the perinatal period is an important cause of cerebral damage and long-term neurological sequelae, and can place much pressure on families and society. Our previous study demonstrated that miRNA-326 reduces neuronal apoptosis by up-regulating the δ-opioid receptor (DOR) under oxygen-glucose deprivation in vitro. In the present study, we aimed to explore the neuroprotective effects of the miRNA-326/DOR axis by inhibiting apoptosis in HIBD using neonatal miRNA-326 knockout mice. Neonatal C57BL/6 mice, neonatal miRNA-326 knockout mice, and neonatal miRNA-326 knockout mice intraperitoneally injected with the DOR inhibitor naltrindole were treated with hypoxic-ischemia (HI). Neurological deficit scores, magnetic resonance imaging, terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling, and Caspase-3, Bax, and B-cell lymphoma 2 (Bcl-2) expression were evaluated on day 2 after HI. Neurobehavioral analyses were performed on days 2 and 28 after HI. Additionally, the Morris water maze test was conducted on days 28. Compared with HI-treated neonatal C57BL/6 mice, HI-treated neonatal miRNA-326 knockout mice had higher neurological deficit scores, smaller cerebral infarction areas, and improved motor function, reaction ability, and long-term spatial learning and memory. These effects were likely the result of inhibiting apoptosis; the DOR inhibitor reversed these neuroprotective effects. Our findings indicate that miRNA-326 knockout plays a neuroprotective effect in neonatal HIBD by inhibiting apoptosis via the target gene DOR.

piRNAs in the human retina and retinal pigment epithelium reveal a potential role in intracellular trafficking and oxidative stress

Long considered active only in the germline, the PIWI/piRNA pathway is now known to play a significant role in somatic cells, especially neurons. In this study, piRNAs were profiled in the human retina and retinal pigment epithelium (RPE). Furthermore, RNA immunoprecipitation with HIWI2 (PIWIL4) in ARPE19 cells yielded 261 piRNAs, and the expression of selective piRNAs in donor eyes was assessed by qRT-PCR. Intriguingly, computational analysis revealed complete and partial seed sequence similarity between piR-hsa-26131 and the sensory organ specific miR-183/96/182 cluster. Furthermore, the expression of retina-enriched piR-hsa-26131 was positively correlated with miR-182 in HIWI2-silenced Y79 cells. In addition, the lnc-ZNF169 sequence matched with two miRNAs of the let-7 family, and piRNAs, piR-hsa-11361 and piR-hsa-11360, which could modulate the regulatory network of retinal differentiation. Interestingly, we annotated four enriched motifs among the piRNAs and found that the piRNAs containing CACAATG and CTCATCAKYG motifs were snoRNA-derived piRNAs, which are significantly associated with developmental functions. However, piRNAs consisting of ACCACTANACCAC and AKCACGYTCSC motifs were mainly tRNA-derived fragments linked to stress response and sensory perception. Additionally, co-expression network analysis revealed cell cycle control, intracellular transport and stress response as the important biological functions regulated by piRNAs in the retina. Moreover, loss of piRNAs in HIWI2 knockdown ARPE19 confirmed altered expression of targets implicated in intracellular transport, circadian clock, and retinal degeneration. Moreover, piRNAs were dysregulated under oxidative stress conditions, indicating their potential role in retinal pathology. Therefore, we postulate that piRNAs, miRNAs, and lncRNAs might have a functional interplay during retinal development and functions to regulate retinal homeostasis.

LncRNA-mir3471-limd1 regulatory network plays critical roles in HIBD

The purpose of this study was to identify the target genes of tcon_00044595, elucidate its activation site, and provide novel insights into the pathogenesis and treatment of neonatal hypoxic-ischemic brain damage (HIBD). Through homologous blast analysis, we identified predicted target sequences in the neighboring regions of the long non-coding RNA (lncRNA) tcon_00044595, suggesting that limd1 is its target gene. Starbase was utilized to identify potential candidate microRNAs associated with the lncRNA. The interaction between the candidate microRNAs and limd1 was investigated and validated using various experimental methods including in vitro cell culture, cell transfection, dual fluorescence reporter detection system, and real-time PCR. Homology alignment analysis revealed that the lncRNA tcon_00044595 exhibited a 246 bp homologous sequence at the 3' end of the adjacent limd1 gene, with a conservation rate of 68%. Analysis conducted on Starbase online identified three potential microRNA candidates: miR-3471, miR-883a-5p, and miR-214-3p. Intracellular expression of the limd1 gene was significantly down-regulated upon transfection with miR-3471, while the other two microRNAs did not produce noticeable effects. Luciferase reporter assays identified two interaction sites (UTR-1, UTR-2) between miR-3471 and the limd1 3'UTR, with UTR-1 exhibiting a strong influence. Further CCK8 assay indicated a protective role of miR-3471 during low oxygen stroke in HIBD. The potential regulatory relationship between lncRNA (tcon_00044595), miR-3471, and the target gene limd1 suggests their involvement in the occurrence and development of HIBD, providing new insights for investigating the underlying mechanisms and exploring targeted therapeutic approaches for HIBD.

Constraint therapy promotes motor cortex remodeling and functional improvement by regulating c-Jun/miR-182-5p/Nogo - A signals in hemiplegic cerebral palsy mice

BACKGROUND

Our previous study has confirmed that constraint-induced movement therapy (CIMT) could promote neural remodeling in hemiplegic cerebral palsy (HCP) mice through Nogo-A/NgR/RhoA/ROCK signaling, however, the upstream mechanism was still unclear. Therefore, the present study aimed to further explore the mechanism of CIMT regulating the expression of Nogo-A in HCP mice.

METHOD

HCP mice were well established through ligating the left common carotid artery of 7-day-old pups and being placed in a hypoxic box which was filled with a mixture of 8% oxygen and 92% nitrogen. CIMT intervention was conducted by taping to fix the entire arm of the contralateral side (left) to force the mice to use the affected limb (right). Bioinformatics prediction and luciferase experiment were performed to confirm that miR-182-5p was targeted with Nogo-A. The beam test and grip test were applied to examine the behavioral performance under the intervention of c-Jun and CIMT. Also, immunofluorescence, Golgi staining, and transmission electron microscopy were conducted to show that the lenti-expression of c-Jun could increases the expression of myelin, and downregulates the expression of Nogo-A under the CIMT on HCP mice.

RESULT

(1) The beam walking test and grip test experiment results showed that compared with the control group, the HCP + nCIMT group's forelimb grasping ability and balance coordination ability were decreased (P < 0.05). (2) The results of Golgi staining, and transmission electron microscopy showed that the thickness of myelin sheath and the density of dendritic spines in the HCP + nCIMT group were lower than those in the control group (P < 0.05). Compared with the HCP + nCIMT group, the cerebral cortex myelin sheath thickness, dendrite spine density and nerve filament expression were increased in HCP + CIMT group (P < 0.05). (3) Immunofluorescence staining showed that the expression of Nogo-A in the cerebral cortex of the HCP + nCIMT group was higher than that of the HCP + CIMT group (P < 0.05). Compared with the HCP + CIMT group, the expression of Nogo-A in the HCP + LC + CIMT group was decreased and, in the HCP, + SC + CIMT group was significantly increased (P < 0.05). Compared with the HCP + nCIMT group, the expression of c-Jun in the control, HCP + CIMT, HCP + LC + nCIMT and HCP + LC + CIMT groups was significantly increased, and in the HCP + SC + CIMT was decreased (P < 0.05). (4) Real-time quantitative polymerase chain reaction (RT-qPCR) results showed that the expression level of miR-182-5p in the HCP + LC + CIMT group was more increased than that in the HCP + nCIMT group (P < 0.05). The expression level of miR-182-5p in the HCP + LC + CIMT group was higher than that in the HCP + LC + nCIMT group and the HCP + SC + CIMT group (P < 0.05).

CONCLUSION

These data identified that CIMT might stimulate the remodeling of neurons and myelin in the motor cortex by partially inhibiting the c-Jun/miR-182-5p/Nogo-A pathway, thereby facilitating the grasping performance and balance function of HCP mice.

Dexmedetomidine suppresses hippocampal astrocyte pyroptosis in cerebral hypoxic-ischemic neonatal rats by upregulating microRNA-148a-3p to inactivate the STAT/JMJD3 axis

OBJECTIVE

Dexmedetomidine (DEX), a selective α2-adrenoceptor agonist, is an anesthetic and sedative agent and has been reported to confer neuroprotective effects after cerebral hypoxic ischemia (CHI). This study was undertaken to elucidate the mechanisms by which microRNA (miR)-148a-3p is involved in the neuroprotective effect of DEX on hypoxic-ischemic brain damage in neonatal rats.

METHODS

Neonatal rats were exposed to CHI conditions, a miR-148a-3p inhibitor, and DEX. Hippocampal astrocytes were isolated to construct an oxygen-glucose deprivation (OGD) model. qRT-PCR and western blot were utilized to inspect miR-148a-3p, STAT1, STAT3, JMJD3, cleaved-Caspase-1, ASC, NLRP3, GSDMD, and GSDMD-N expression in rats and astrocytes. TUNEL staining was employed to measure astrocyte apoptosis rate, immunofluorescence to inspect cleaved-Caspase-1 and ASC levels, and ELISA to determine IL-1β and IL-18 expression. The target genes of miR-148a-3p were predicted using online software and verified by a dual-luciferase reporter gene assay.

RESULTS

A prominent increase in astrocyte apoptosis rate and the expression of pyroptosis- and inflammation-related factors were found in rats with CHI and OGD-treated astrocytes. DEX suppressed astrocyte apoptosis rate and decreased expression of pyroptosis- and inflammation-related factors. Knockdown of miR-148a-3p facilitated astrocyte pyroptosis, indicating that DEX exerted its protective effect by upregulating miR-148a-3p. miR-148a-3p negatively mediated STAT to inactivate JMJD3. Overexpression of STAT1 and STAT3 facilitated pyroptosis in astrocytes, which was negated by the overexpression of miR-148a-3p.

CONCLUSION

DEX inhibited hippocampal astrocyte pyroptosis by upregulating miR-148a-3p to inactivate the STAT/JMJD3 axis, thereby alleviating cerebral damage in neonatal rats with CHI.

Deciphering clock genes as emerging targets against aging

The old people often suffer from circadian rhythm disturbances, which in turn accelerate aging. Many aging-related degenerative diseases such as Alzheimer's disease, Parkinson's disease, and osteoarthritis have an inextricable connection with circadian rhythm. In light of the predominant effects of clock genes on regulating circadian rhythm, we systematically present the elaborate network of roles that clock genes play in aging in this review. First, we briefly introduce the basic background regarding clock genes. Second, we systemically summarize the roles of clock genes in aging and aging-related degenerative diseases. Third, we discuss the relationship between clock genes polymorphisms and aging. In summary, this review is intended to clarify the indispensable roles of clock genes in aging and sheds light on developing clock genes as anti-aging targets.

2.4 GHz Electromagnetic Field Influences the Response of the Circadian Oscillator in the Colorectal Cancer Cell Line DLD1 to miR-34a-Mediated Regulation

Radiofrequency electromagnetic fields (RF-EMF) exert pleiotropic effects on biological processes including circadian rhythms. miR-34a is a small non-coding RNA whose expression is modulated by RF-EMF and has the capacity to regulate clock gene expression. However, interference between RF-EMF and miR-34a-mediated regulation of the circadian oscillator has not yet been elucidated. Therefore, the present study was designed to reveal if 24 h exposure to 2.4 GHz RF-EMF influences miR-34a-induced changes in clock gene expression, migration and proliferation in colorectal cancer cell line DLD1. The effect of up- or downregulation of miR-34a on DLD1 cells was evaluated using real-time PCR, the scratch assay test and the MTS test. Administration of miR-34a decreased the expression of per2, bmal1, sirtuin1 and survivin and inhibited proliferation and migration of DLD1 cells. When miR-34a-transfected DLD1 cells were exposed to 2.4 GHz RF-EMF, an increase in cry1 mRNA expression was observed. The inhibitory effect of miR-34a on per2 and survivin was weakened and abolished, respectively. The effect of miR-34a on proliferation and migration was eliminated by RF-EMF exposure. In conclusion, RF-EMF strongly influenced regulation mediated by the tumour suppressor miR-34a on the peripheral circadian oscillator in DLD1 cells.

A time to heal: microRNA and circadian dynamics in cutaneous wound repair

Many biological systems have evolved circadian rhythms based on the daily cycles of daylight and darkness on Earth. Such rhythms are synchronised or entrained to 24-h cycles, predominantly by light, and disruption of the normal circadian rhythms has been linked to elevation of multiple health risks. The skin serves as a protective barrier to prevent microbial infection and maintain homoeostasis of the underlying tissue and the whole organism. However, in chronic non-healing wounds such as diabetic foot ulcers (DFUs), pressure sores, venous and arterial ulcers, a variety of factors conspire to prevent wound repair. On the other hand, keloids and hypertrophic scars arise from overactive repair mechanisms that fail to cease in a timely fashion, leading to excessive production of extracellular matrix (ECM) components such as such as collagen. Recent years have seen huge increases in our understanding of the functions of microRNAs (miRNAs) in wound repair. Concomitantly, there has been growing recognition of miRNA roles in circadian processes, either as regulators or targets of clock activity or direct responders to external circadian stimuli. In addition, miRNAs are now known to function as intercellular signalling mediators through extracellular vesicles (EVs). In this review, we explore the intersection of mechanisms by which circadian and miRNA responses interact with each other in relation to wound repair in the skin, using keratinocytes, macrophages and fibroblasts as exemplars. We highlight areas for further investigation to support the development of translational insights to support circadian medicine in the context of these cells.

Mesenchymal stem cell-derived exosomal microRNA-182-5p alleviates myocardial ischemia/reperfusion injury by targeting GSDMD in mice

Recent evidence indicates that exosomes derived from mesenchymal stem cells (MSCs) confer protective effects against myocardial ischemia/reperfusion (I/R) injury. Exosomes are carriers of potentially protective endogenous molecules, including microRNAs (miRNAs/miRs). The current study set out to test the effects of transferring miR-182-5p from MSC-derived exosomes into myocardial cells on myocardial I/R injury. First, an I/R mouse model was developed by left anterior descending coronary artery occlusion, and myocardial cells were exposed to hypoxia/reoxygenation (H/R) for in vitro I/R model establishment. Loss- and gain-of-function experiments of miR-182-5p and GSDMD were conducted to explore the effects of miR-182-5p via MSC-derived exosomes on cell pyroptosis and viability. GSDMD was robustly expressed in I/R-injured myocardial tissues and H/R-exposed myocardial cells. GSDMD upregulation promoted H/R-induced myocardial cell pyroptosis and reduced viability, corresponding to increased lactate dehydrogenase release, reactive oxygen species production, and pyroptosis. A luciferase assay demonstrated GSDMD as a target of miR-182-5p. In addition, exosomal miR-182-5p was found to diminish GSDMD-dependent cell pyroptosis and inflammation induced by H/R. Furthermore, MSC-derived exosomes carrying miR-182-5p improved cardiac function and reduced myocardial infarction, accompanied with reduced inflammation and cell pyroptosis in vivo. Taken together, our findings suggest a cardioprotective effect of exosomal miR-182-5p against myocardial I/R injury, shedding light on an attractive therapeutic strategy.

MiR-375-3p mediates reduced pineal function in hypoxia-ischemia brain damage

The functional roles of microRNAs (miRNAs) have been studied in various diseases, including hypoxic-ischemic brain damage (HIBD). However, changes in the expression of miRNAs and the underlying mechanisms in the pineal gland during HIBD remain unknown. Based on the previous study by microRNA array, hundreds of miRNAs showed altered expression patterns in the pineal gland in a rat model of HIBD. MiR-375-3p was found to be significantly upregulated and abundant in the pineal gland. Further investigation in an in vitro HI model of pinealocytes showed that miRNA-375 exacerbated the damage to pineal function. After oxygen-glucose deprivation / reoxygenation (OGD/R), miR-375-3p expression increased, while aralkylamine N-acetyltransferase (AANAT) expression and melatonin (MT) secretion decreased. Overexpression of miRNA-375 in pinealocytes aggravated the influence of OGD/R on AANAT expression and MT secretion. Because miRNA-375 overexpression in pinealocytes induced decreased rasd1 mRNA and protein expression, rasd1 may mediate the effect of miR-375-3p on pineal function. Furthermore, miR-375-3p aggravated the cognitive impairment caused by HIBD in rats, as observed by Morris water maze test, and also affected emotion and circadian rhythm in HIBD-treated rats. Thus, miR-375-3p may be a key regulatory molecule in the pineal gland following HIBD, and targeting of miR-375-3p may represent a new strategy for the treatment of HIBD.

Timing without coding: How do long non-coding RNAs regulate circadian rhythms?

Long non-coding RNAs (lncRNAs) are a new class of regulatory RNAs that play important roles in disease development and a variety of biological processes. Recent studies have underscored the importance of lncRNAs in the circadian clock system and demonstrated that lncRNAs regulate core clock genes and the core clock machinery in mammals. In this review, we provide an overview of our current understanding of how lncRNAs regulate the circadian clock without coding a protein. We also offer additional insights into the challenges in understanding the functions of lncRNAs and other unresolved questions in the field. We do not cover other regulatory ncRNAs even though they also play important roles; readers are highly encouraged to refer to other excellent reviews on this topic.

A genome-wide microRNA screen identifies the microRNA-183/96/182 cluster as a modulator of circadian rhythms

The regulatory mechanisms of circadian rhythms have been studied primarily at the level of the transcription-translation feedback loops of protein-coding genes. Regulatory modules involving noncoding RNAs are less thoroughly understood. In particular, emerging evidence has revealed the important role of microRNAs (miRNAs) in maintaining the robustness of the circadian system. To identify miRNAs that have the potential to modulate circadian rhythms, we conducted a genome-wide miRNA screen using U2OS luciferase reporter cells. Among 989 miRNAs in the library, 120 changed the period length in a dose-dependent manner. We further validated the circadian regulatory function of an miRNA cluster, miR-183/96/182, both in vitro and in vivo. We found that all three members of this miRNA cluster can modulate circadian rhythms. Particularly, miR-96 directly targeted a core circadian clock gene, PER2. The knockout of the miR-183/96/182 cluster in mice showed tissue-specific effects on circadian parameters and altered circadian rhythms at the behavioral level. This study identified a large number of miRNAs, including the miR-183/96/182 cluster, as circadian modulators. We provide a resource for further understanding the role of miRNAs in the circadian network and highlight the importance of miRNAs as a genome-wide layer of circadian clock regulation.

Expression characteristics of pineal miRNAs at ovine different reproductive stages and the identification of miRNAs targeting the AANAT gene

Background

Many recent studies have shown that miRNAs play important roles in the regulation of animal reproduction, including seasonal reproduction. The pineal gland is a crucial hub in the regulation of seasonal reproduction. However, little is known about the expression characteristics of pineal miRNAs in different reproductive seasons (anestrus and breeding season). Therefore, the expression profiles and regulatory roles of ovine pineal miRNAs were investigated during different reproductive stages using Solexa sequencing technology and dual luciferase reporter assays.

Results

A total of 427 miRNAs were identified in the sheep pineal gland. Significant differences in miRNA expression were demonstrated between anestrus and the breeding season in terms of the frequency distributions of miRNA lengths, number of expressed miRNAs, and specifically and highly expressed miRNAs in each reproductive stage. KEGG analysis of the differentially expressed (DE) miRNAs between anestrus and the breeding season indicated that they are significantly enriched in pathways related to protein synthesis, secretion and uptake. Furthermore, transcriptome analysis revealed that many target genes of DE miRNAs in the ribosome pathway showed relatively low expression in the breeding season. On the other hand, analyses combining miRNA-gene expression data with target relationship validation in vitro implied that miR-89 may participate in the negative regulation of aralkylamine N-acetyltransferase (AANAT) mRNA expression by targeting its 3’UTR at a unique binding site.

Conclusions

Our results provide new insights into the expression characteristics of sheep pineal miRNAs at different reproductive stages and into the negative regulatory effects of pineal miRNAs on AANAT mRNA expression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07536-y.

Astrocyte-derived exosomes carry microRNA-17-5p to protect neonatal rats from hypoxic-ischemic brain damage via inhibiting BNIP-2 expression

Exosomes play critical roles in neurogenesis. This study aims to explore the mechanism of astrocyte-derived exosomes in neonatal rats with hypoxic-ischemic brain damage (HIBD). Astrocytes were collected and astrocyte-derived exosomes were isolated and identified. Neonatal rats were pre-treated with exosomes and then subjected to HIBD induction. Then the neurobehaviors, neuronal apoptosis, inflammation and oxidative stress in rat brain were measured. Differentially expressed microRNAs (miRNAs) in rat brain before and after HI procedure were analyzed. H19-7 cells were subjected to oxygen and glucose deprivation (OGD) for in vitro studies. Target relation between miR-17-5p and BNIP2 was identified. Gain- and loss-of functions of miR-17-5p and BNIP2 were conducted to identify their roles in viability, apoptosis, oxidative stress and inflammation of OGD-treated cells. Collectively, astrocyte-derived exosomes improved neurobehaviors, and reduced cerebral infarction, neuronal apoptosis, oxidative and inflammation in vivo and in vitro. The exosomes carried miR-17-5p bound to BNIP2 and negatively regulated BNIP2 expression in OGD-treated cells. Over-expression of miR-17-5p increased viability, and decreased OGD-induced apoptosis, oxidative stress and inflammation of H19-7 cells, which were reversed by over-expression of BNIP2. Taken together, the study suggested that astrocyte-derived exosomes could carry miR-17-5p to protect neonatal rats from HIBD via inhibiting BNIP-2 expression.

The role of pineal microRNA-325 in regulating circadian rhythms after neonatal hypoxic-ischemic brain damage

Circadian rhythm disorder is a common, but often neglected, consequence of neonatal hypoxic-ischemic brain damage (HIBD). However, the underlying molecular mechanisms remain largely unknown. We previously showed that, in a rat model of HIBD, up-regulation of microRNA-325 (miR-325) in the pineal gland is responsible for the suppression of Aanat, a key enzyme involved in melatonin synthesis and circadian rhythm regulation. To better understand the mechanism by which miR-325 affects circadian rhythms in neonates with HIBD, we compared clinical samples from neonates with HIBD and samples from healthy neonates recruited from the First Affiliated Hospital of Soochow University (Dushuhu Branch) in 2019. We found that circulating miR-325 levels correlated positively with the severity of sleep and circadian rhythm disorders in neonates with HIBD. Furthermore, a luciferase reporter gene assay revealed that LIM homeobox 3 (LHX3) is a novel downstream target of miR-325. In addition, in miR-325 knock-down mice, the transcription factor LHX3 exhibited an miR-325-dependent circadian pattern of expression in the pineal gland. We established a neonatal mouse model of HIBD by performing double-layer ligation of the left common carotid artery and exposing the pups to a low-oxygen environment for 2 hours. Lhx3 mRNA expression was significantly down-regulated in these mice and partially rescued in miR-325 knockout mice subjected to the same conditions. Finally, we showed that improvement in circadian rhythm-related behaviors in animals with HIBD was dependent on both miR-325 and LHX3. Taken together, our findings suggest that the miR-325-LHX3 axis is responsible for regulating circadian rhythms and provide novel insights into the identification of potential therapeutic targets for circadian rhythm disorders in patients with neonatal HIBD. The clinical trial was approved by Institutional Review Board of Children's Hospital of Soochow University (approval No. 2015028) on July 20, 2015. Animal experiments were approved by Animal Care and Use Committee, School of Medicine, Soochow University, China (approval No. XD-2016-1) on January 15, 2016.

Multi-Organ Dysfunction in Cerebral Palsy

Cerebral Palsy (CP) describes a heterogenous group of non-progressive disorders of posture or movement, causing activity limitation, due to a lesion in the developing brain. CP is an umbrella term for a heterogenous condition and is, therefore, descriptive rather than a diagnosis. Each case requires detailed consideration of etiology. Our understanding of the underlying cause of CP has developed significantly, with areas such as inflammation, epigenetics and genetic susceptibility to subsequent insults providing new insights. Alongside this, there has been increasing recognition of the multi-organ dysfunction (MOD) associated with CP, in particular in children with higher levels of motor impairment. Therefore, CP should not be seen as an unchanging disorder caused by a solitary insult but rather, as a condition which evolves over time. Assessment of multi-organ function may help to prevent complications in later childhood or adulthood. It may also contribute to an improved understanding of the etiology and thus may have an implication in prevention, interventional methods and therapies. MOD in CP has not yet been quantified and a scoring system may prove useful in allowing advanced clinical planning and follow-up of children with CP. Additionally, several biomarkers hold promise in assisting with long-term monitoring. Clinicians should be aware of the multi-system complications that are associated with CP and which may present significant diagnostic challenges given that many children with CP communicate non-verbally. A step-wise, logical, multi-system approach is required to ensure that the best care is provided to these children. This review summarizes multi-organ dysfunction in children with CP whilst highlighting emerging research and gaps in our knowledge. We identify some potential organ-specific biomarkers which may prove useful in developing guidelines for follow-up and management of these children throughout their lifespan.

TP53-induced glycolysis and apoptosis regulator alleviates hypoxia/ischemia-induced microglial pyroptosis and ischemic brain damage

Our previous studies have demonstrated that TP53-induced glycolysis and apoptosis regulator (TIGAR) can protect neurons after cerebral ischemia/reperfusion. However, the role of TIGAR in neonatal hypoxic-ischemic brain damage (HIBD) remains unknown. In the present study, 7-day-old Sprague-Dawley rat models of HIBD were established by permanent occlusion of the left common carotid artery followed by 2-hour hypoxia. At 6 days before induction of HIBD, a lentiviral vector containing short hairpin RNA of either TIGAR or gasdermin D (LV-sh_TIGAR or LV-sh_GSDMD) was injected into the left lateral ventricle and striatum. Highly aggressively proliferating immortalized (HAPI) microglial cell models of in vitro HIBD were established by 2-hour oxygen/glucose deprivation followed by 24-hour reoxygenation. Three days before in vitro HIBD induction, HAPI microglial cells were transfected with LV-sh_TIGAR or LV-sh_GSDMD. Our results showed that TIGAR expression was increased in the neonatal rat cortex after HIBD and in HAPI microglial cells after oxygen/glucose deprivation/reoxygenation. Lentivirus-mediated TIGAR knockdown in rats markedly worsened pyroptosis and brain damage after hypoxia/ischemia in vivo and in vitro. Application of exogenous nicotinamide adenine dinucleotide phosphate (NADPH) increased the NADPH level and the glutathione/oxidized glutathione ratio and decreased reactive oxygen species levels in HAPI microglial cells after oxygen/glucose deprivation/reoxygenation. Additionally, exogenous NADPH blocked the effects of TIGAR knockdown in neonatal HIBD in vivo and in vitro. These findings show that TIGAR can inhibit microglial pyroptosis and play a protective role in neonatal HIBD. The study was approved by the Animal Ethics Committee of Soochow University of China (approval No. 2017LW003) in 2017.

Identifying daily changes in circRNAs and circRNA-associated-ceRNA networks in the rat pineal gland

Circular RNAs (circRNAs) are a new class of covalently closed circular RNA molecules that are involved in many biological processes. However, information about circRNAs in the pineal gland, particularly that of rats, is limited. To establish resources for the study of the rat pineal gland, we performed transcriptome analysis of the pineal glands during the day and night. In this study, 1413 circRNAs and 1989 miRNAs were identified in the pineal gland of rats during the night and day using the Illumina platform. Forty differentially expressed circRNAs and 93 differentially expressed miRNAs were obtained, among which 20 circRNAs and 37 miRNAs were significantly upregulated during the day and 20 circRNAs and 56 miRNAs were significantly upregulated during the night. As circRNAs have been reported to work as miRNA sponges, we predicted 15940 interactions among 40 circRNAs, 93 miRNAs and 400 mRNAs with differential diurnal expression using miRanda and TargetScan to build a ceRNA regulatory network in the rat pineal gland. The diurnal expression profile of circRNAs in the rat pineal gland may provide additional information about the role of circRNAs in regulating changes in melatonin circadian rhythms. The analyzed data reported in this study will be an important resource for future studies to elucidate the altered physiology of circRNAs in diurnal rhythms.

Micro RNAs and the biological clock: a target for diseases associated with a loss of circadian regulation

Background

Circadian clocks are self-sustaining oscillators that coordinate behavior and physiology over a 24 hour period, achieving time-dependent homeostasis with the external environment. The molecular clocks driving circadian rhythmic changes are based on intertwined transcriptional/translational feedback loops that combine with a range of environmental and metabolic stimuli to generate daily internal programing. Understanding how biological rhythms are generated throughout the body and the reasons for their dysregulation can provide avenues for temporally directed therapeutics.

Summary

In recent years, microRNAs have been shown to play important roles in the regulation of the circadian clock, particularly in Drosophila, but also in some small animal and human studies. This review will summarize our current understanding of the role of miRNAs during clock regulation, with a particular focus on the control of clock regulated gene expression.

Developmental stage-specific A-to-I editing pattern in the postnatal pineal gland of pigs (Sus scrofa)

Background

RNA editing is a widespread post-transcriptional modification mechanism in mammalian genomes. Although many editing sites have been identified in domestic pigs (Sus scrofa), little is known about the characteristics and dynamic regulation of RNA editing in the pineal gland (PG), a small neuroendocrine gland that synthesizes and secretes melatonin, which is primarily responsible to modulate sleep patterns.

Results

This study analyzed the expression of adenosine-to-inosine (A-to-I) editing regulators and profiled the first dynamic A-to-I RNA editome during postnatal PG development. The results identified ADAR1 as the most abundantly expressed ADAR enzyme, which was down-regulated during postnatal PG development. Furthermore, 47,284 high-confidence RNA editing sites were identified, the majority of which (93.6%) were of the canonical A-to-I editing type, followed by C-to-T editing. Analysis of its characteristics showed that the A-to-I editing sites mostly localized in SINE retrotransposons PRE-1/Pre0_SS. Moreover, a strong deficiency and preference for guanine nucleotides at positions of one base upstream or downstream were found, respectively. The overall editing level at the puberty stage was higher than at both infancy and adulthood stages. Additionally, genome-wide RNA editing was found to exhibit a dynamic stage-specific fashion (postnatally). Genes that underwent developmental changes in RNA editing were associated with catabolic processes as well as protein localization and transport functions, implying that RNA editing might be responsible for the molecular machineries of the postnatal developing PG. Remarkably, RNA editing in 3'-UTRs might regulate gene expression by influencing miRNA binding during PG development.

Conclusions

This study profiles the first comprehensive developmental RNA editome in the pig PG, which contributes to the understanding of the importance of post-transcriptionally mediated regulation during mammalian postnatal PG development. Moreover, this study widely extends RNA editome resources in mammals.

MicroRNA: A Key Player for the Interplay of Circadian Rhythm Abnormalities, Sleep Disorders and Neurodegenerative Diseases

Circadian rhythms are endogenous 24-h oscillators that regulate the sleep/wake cycles and the timing of biological systems to optimize physiology and behavior for the environmental day/night cycles. The systems are basically generated by transcription-translation feedback loops combined with post-transcriptional and post-translational modification. Recently, evidence is emerging that additional non-coding RNA-based mechanisms are also required to maintain proper clock function. MicroRNA is an especially important factor that plays critical roles in regulating circadian rhythm as well as many other physiological functions. Circadian misalignment not only disturbs the sleep/wake cycle and rhythmic physiological activity but also contributes to the development of various diseases, such as sleep disorders and neurodegenerative diseases. The patient with neurodegenerative diseases often experiences profound disruptions in their circadian rhythms and/or sleep/wake cycles. In addition, a growing body of recent evidence implicates sleep disorders as an early symptom of neurodegenerative diseases, and also suggests that abnormalities in the circadian system lead to the onset and expression of neurodegenerative diseases. The genetic mutations which cause the pathogenesis of familial neurodegenerative diseases have been well studied; however, with the exception of Huntington's disease, the majority of neurodegenerative diseases are sporadic. Interestingly, the dysfunction of microRNA is increasingly recognized as a cause of sporadic neurodegenerative diseases through the deregulated genes related to the pathogenesis of neurodegenerative disease, some of which are the causative genes of familial neurodegenerative diseases. Here we review the interplay of circadian rhythm disruption, sleep disorders and neurodegenerative disease, and its relation to microRNA, a key regulator of cellular processes.

Study of the modulatory mechanism of the miR-182-Clock axis in circadian rhythm disturbance after hypoxic–ischemic brain damage

Hypoxic–ischemic encephalopathy (HIE) in neonates can lead to severe chronic neurological deficit, including mental retardation, epilepsy, and sleep–wake cycle (SWC) disorder. Among these defects, little is known about the molecular mechanism of circadian rhythm disorder after HIE. Therefore, further study of sleep problems and its mechanism in HIE children will provide new ideas for clinical treatment of HIE children. For pediatric patients with cerebral ischemia, somnipathy often occurs due to visual and airway abnormalities. From May 2010 to August 2013, 128 newborns with history of HIE were followed up. Meanwhile, 88 normal full-term newborns in the same period were taken as the control group. The clinical data of the patients were collected and the sleep status was assessed by questionnaire. To establish the hypoxic–ischemic brain injury model of neonatal rats and analyze the mechanism of mir-182 in the circadian rhythm disorder caused by pineal function injury. The core clock genes during the regulation of the circadian clock were explored by bioinformatics methods. Patients’ sleep quality was affected by the circadian rhythm and respiratory problems; the pineal gland can regulate the core clock genes in the circadian clock during regulation. miR-182 was highly expressed in the pineal gland after hypoxic–ischemic brain damage (HIBD). Children with mild and moderate HIE showed significant sleep disorders in varying degrees, which provided a clinical basis for improving the long-term prognosis of children with HIE through targeted treatment of sleep disorders. MiR-182 is highly expressed in the pineal gland and is related to the expression of CLOCK protein. CLOCK gene is the target gene of miR-182, which provides a new target for the treatment of rhythm disorder related to the damage of pineal function caused by HIBD.

MicroRNA-9 mediated the protective effect of ferulic acid on hypoxic-ischemic brain damage in neonatal rats

Neonatal hypoxic-ischemic brain damage (HIBD) is prone to cognitive and memory impairments, and there is no effective clinical treatment until now. Ferulic acid (FA) is found within members of the genus Angelica, reportedly shows protective effects on neuronal damage. However, the protective effects of FA on HIBD remains unclear. In this study, using the Morris water maze task, we herein found that the impairment of spatial memory formation in adult rats exposed to HIBD was significantly reversed by FA treatment and the administration of LNA-miR-9. The expression of miRNA-9 was detected by RT-PCR analyses, and the results shown that miRNA-9 was significantly increased in the hippocampus of neonatal rats following HIBD and in the PC12 cells following hypoxic-ischemic injury, while FA and LNA-miR-9 both inhibited the expression of miRNA-9, suggesting that the therapeutic effect of FA was mainly attributed to the inhibition of miRNA-9 expression. Indeed, the silencing of miR-9 by LNA-miR-9 or FA similarly attenuated neuronal damage and cerebral atrophy in the rat hippocampus after HIBD, which was consistent with the restored expression levels of brain-derived neurotrophic factor (BDNF). Therefore, our findings indicate that FA treatment may protect against neuronal death through the inhibition of miRNA-9 induction in the rat hippocampus following hypoxic-ischemic damage.

The role of a lncRNA (TCONS_00044595) in regulating pineal CLOCK expression after neonatal hypoxia-ischemia brain injury

A common, yet often neglectable, feature of neonatal hypoxic-ischemic brain damage (HIBD) is circadian rhythm disorders resulted from pineal gland dysfunction. Our previous work demonstrated that miRNAs play an important role in regulating key circadian genes in the pineal gland post HIBD [5,21]. In current study, we sought out to extend our investigation by profiling expression changes of pineal long non-coding RNAs (lncRNAs) upon neonatal HIBD using RNA-Seq. After validating lncRNA changes, we showed that one lncRNA: TCONS_00044595 is highly enriched in the pineal gland and exhibits a circadian expression pattern. Next, we performed bioinformatic analysis to predict the lncRNA-miRNA regulatory network and identified 168 miRNAs that potentially targetlncRNA TCONS_00044595. We further validated the bona fide interaction between one candidate miRNA: miR-182, a known factor to regulate pineal Clock expression, and lncRNA TCONS_00044595. Finally, we showed that suppression of lncRNA TCONS_00044595 alleviated the CLOCK activation both in the cultured pinealocytes under OGD conditions and in the pineal gland post HIBD in vivo. Our study thus shed light into novel mechanisms of pathophysiology of pineal dysfunction post neonatal HIBD.

lncRNA NEAT1 Binds to MiR-339-5p to Increase HOXA1 and Alleviate Ischemic Brain Damage in Neonatal Mice

Hypoxic-ischemic brain damage (HIBD) is a major cause of fatality and morbidity in neonates. However, current treatment approaches to alleviate HIBD are not effective. Various studies have highlighted the role of microRNAs (miRNAs) in various biological functions in multiple diseases. This study investigated the role of miR-339-5p in HIBD progression. Neonatal HIBD mouse model was induced by ligation of the right common carotid artery. Neuronal cell model exposed to oxygen-glucose deprivation (OGD) was also established. The miR-339-5p expression in mouse brain tissues and neuronal cells was quantified, and the effects of miR-339-5p on neuronal cell activity and apoptosis induced by hypoxia-ischemia were explored. The overexpression or knockdown of long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in hippocampal neurons was used to determine the effect of lncRNA NEAT1 on the expression of miR-339-5p and homeobox A1 (HOXA1) and apoptosis. Short hairpin RNA targeting lncRNA NEAT1 and miR-339-5p antagomir were used in neonatal HIBD mice to identify their roles in HIBD. Our results revealed that miR-339-5p was downregulated in neonatal HIBD mice and neuronal cells exposed to OGD. Downregulated miR-339-5p promoted neuronal cell viability and suppressed apoptosis during hypoxia-ischemia. Moreover, lncRNA NEAT1 competitively bound to miR-339-5p to increase HOXA1 expression and inhibited neuronal cell apoptosis under hypoxic-ischemic conditions. The key observations of the current study present evidence demonstrating that lncRNA NEAT1 upregulated HOXA1 to alleviate HIBD in mice by binding to miR-339-5p.

microRNA-182 Negatively Influences the Neuroprotective Effect of Apelin Against Neuronal Injury in Epilepsy

PURPOSE

To explore the neuroprotective effects and mechanisms of Apelin (APLN), and to study the regulation of APLN expression by microRNA (miRNA) in epilepsy.

MATERIALS AND METHODS

In vitro and in vivo epileptic models were established with hippocampal neurons and Wistar rats. Apoptosis of neurons was identified by flow cytometry. Western blotting was used to detect the expression of proteins, and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to analyze the expression of miRNA and messenger RNA (mRNA). Bioinformatics software was used to predict target genes of miRNA, which were confirmed by dual-luciferase reporter gene system and functional experiments.

RESULTS

Our study demonstrated protective effects of APLN against neuronal death in epilepsy both in vitro and in vivo. The underlying mechanisms involved are inhibiting the expression of metabotropic glutamate receptor 1 (mGluR1), Bax, and caspase-3; promoting the expression of Bcl-2; and increasing phosphorylated-AKT (p-AKT) levels in neurons. For the first time, we found that miR-182 could negatively regulate both transcriptional and translational levels of APLN, and that the up-regulation of miR-182 inhibited the expression of APLN and Bcl-2, and promoted the expression of Bax and caspase-3.

CONCLUSION

APLN could protect the neurons from injury in epilepsy by regulating the expression of apoptosis-associated proteins and mGluR1 and increasing p-AKT levels, which were attenuated by miR-182. Hence, miR-182/APLN may be potential targets for epilepsy control and treatment.

The role of microglia mediated pyroptosis in neonatal hypoxic-ischemic brain damage

Neonatal hypoxic-ischemic encephalopathy (HIE) often leads to neonatal death or severe, irreversible neurological deficits. Pathologically, the occurrence of massive cell death and subsequent inflammation suggested that pyroptosis, an inflammation associated programed cell death, might play a role in HIE. Here, by measuring changes of key molecules in pyroptosis pathway in HIE patients, we discovered that their elevation levels tightly correlate with the severity of HIE. Next, we demonstrated that application of MCC950, a small molecule to inhibit NLRP3 inflammasome and thus pyroptosis, substantially alleviated pyroptosis and the injury severity in rats with neonatal hypoxic-ischemic brain damage (HIBD). Mechanistically, we showed that NLRP-3/caspase-1/GSDMD axis is required for microglia pyroptosis and activation. Our data demonstrated that microglia mediated pyroptosis played a crucial role in neonatal HIE, which shed lights into the development of intervention avenues targeting pyroptosis to treat HIE and traumatic brain injuries.

MicroRNA-204 may participate in the pathogenesis of hypoxic-ischemic encephalopathy through targeting KLLN

Hypoxic-ischemic encephalopathy (HIE) is a common neonatal disease that can lead to high neonatal mortality rates. Previous studies have indicated that microRNAs (miRs) may be involved in the pathogenesis of HIE; however, the specific mechanisms underlying their involvement require further investigation. The aim of the present study was to investigate the roles of miR-204 and its target gene killin p53 regulated DNA replication inhibitor (KLLN) in HIE using rat HIE models. Brain injury was induced by surgery and incubation of hypoxic incubator brain using 10-day-old pup rats. On day 3, rats were sacrificed, and the infarct size of the brain was determined using a tetrazolium chloride assay. Terminal deoxynucleotidyl transferase UTP nick-end labeling staining was performed to detect the cell death rate in the brain tissue. Following this, the brain tissues were collected, and reverse transcription-quantitative polymerase chain reaction, western blot analysis and immunohistochemistry assays were performed to examine the expression levels of miR-204 and KLLN. Furthermore, neurons were cultured and transfected with miR-204 inhibitors or mimics, and the effect of miR-204 on the proliferation and apoptosis of neurons was examined using MTT and flow cytometric assays. Finally, a dual-luciferase reporter assay was performed to confirm whether KLLN is a direct target of miR-204. The expression of miR-204 was significantly downregulated and the expression of KLLN was significantly increased in the brain tissue of HIE rats (P<0.001). In addition, the transfection with miR-204 inhibitors significantly decreased the proliferation rates and significantly increased the apoptosis rate of neurons; however, transfection with miR-204 mimics prompted the opposite results. The dual-luciferase reporter assay also confirmed that KLLN is a direct target of miR-204. Taken together, the results of the present study demonstrated that miR-204 was downregulated in HIE and that miR-204 may serve important roles in the pathogenesis of HIE through targeting KLLN.

Identification and functional analysis of microRNAs in rats following focal cerebral ischemia injury

MicroRNA sequencing (miRNA‑seq) was performed in the present study to investigate miRNA expression profiles in infarcted brain areas following focal cerebral ischemia induced by middle cerebral artery occlusion in rats. In total, 20 miRNAs were identified to be upregulated and 17 to be downregulated in the infarct area. The expression levels of six differentially expressed miRNAs (DEmiRs), miR‑211‑5p, miR‑183‑5p, miR‑10b‑3p, miR‑182, miR‑217‑5p and miR‑96‑5p, were examined by reverse transcription‑​quantitative polymerase chain reaction. Subsequently, a miRNA‑mRNA network was constructed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to investigate the functions of the mRNAs targeted by these DEmiRs. The present study aimed to investigate the association between miRNAs and cerebral ischemia to provide potential insight into the molecular mechanisms underlying ischemic stroke.

Association of miR-182 expression in amniotic fluid with intrauterine infection and brain injury in premature infants

Changes of micro-ribonucleic acid-182 (miR-182) level in cases of intrauterine infection were investigated to explore the association between miR-182 level change and brain injury in premature infants. A total of 257 preterm infants born in obstetrics department of Jinan Maternity and Child Care Hospital from February 2015 to February 2017 were enrolled in this study. These preterm infants were divided into infected group (n=113) and uninfected group (n=144) based on pathological diagnosis results. Quantitative polymerase chain reaction (qPCR) was employed to detect miR-182 level in amniotic fluid. Bregmatic sagittal and coronal plus lateral fontanel craniocerebral ultrasound, craniocerebral computed tomography (CT) and craniocerebral magnetic resonance imaging examinations were conducted in these preterm infants within one week after birth, and the results were recorded. The relationship between intrauterine infection and brain injury in premature infants was analyzed, and the association of miR-182 level with brain injury was explored. According to pathological diagnoses, brain injury was found in 61 of 113 infants in the infected group, with an incidence rate of 54.0%; and 28 of 144 infants in uninfected group, with an incidence rate of 19.4%; among them, 3 had placental infection caused by intrauterine infection in pregnant women, and all preterm infants had brain damage. Risk value of brain injury in premature infants due to intrauterine infection was hazard ratio (HR) = 2.2611, χ2=33.798, P<0.02. Infected group had a higher miR-182 level in comparison with uninfected group, and the difference in miR-182 level between infected group and uninfected group was statistically significant (P<0.05). Intrauterine infection can lead to an increase in miR-182 level; growth in miR-182 level is closely related to brain injury in premature infants.

MiR-182 alleviates the development of cyanotic congenital heart disease by suppressing HES1

miRNAs have been pointed to play critical roles in the protection and development of cyanotic congenital heart disease (CHD). MiR-182 is found to be associated with multiple heart diseases. However, little is known about the function and underlying mechanisms of miR-182 on cyanotic CHD. Here, H9c2 cells were exposed to hypoxia to construct the model of cyanotic CHD in vitro. qRT-PCR assay revealed that miR-182 expression was downregulated in serum samples from patients with cyanotic CHD and hypoxia-induced cardiomyocytes. Gain- and loss-of-function demonstrated that miR-182 overexpression promoted cell proliferation and suppressed apoptosis in hypoxia-induced H9c2 cells, while miR-182 knockdown repressed cell proliferation and promoted apoptosis. Dual-luciferase reporter assay verified that HES1 was a direct target of miR-182, and miR-182 repressed HES1 expression by binding to its 3'-UTR. Moreover, miR-182-mediated regulatory effect on cell proliferation and apoptosis was reversed by the restoration of HES1 expression. In conclusion, our study demonstrated that miR-182 exerted protection effect through suppressing HES1 in hypoxia-induced cardiomyocytes, highlighting its role as a potential therapeutic strategy for cyanotic CHD.

Salidroside protects hypoxia-induced injury by up-regulation of miR-210 in rat neural stem cells

Neonatal brain hypoxia is a disease that affects the nervous system in children. Salidroside is a compound that has an anti-hypoxic effect, but the mechanism of salidroside in neonatal cerebral hypoxia is unclear. Hence, we investigated the regulatory effect and mechanism of salidroside on hypoxic-induced injury of neural stem cells (NSCs). NSCs derived from embryo 14 Sprague-Dawley rats were treated by hypoxia, followed by the treatment of 0.8 mM salidroside. The expression levels of miR-210 and BTG3 in NSCs were altered by transfection. Cell viability and apoptosis were examined by CCK-8 and flow cytometry analysis. qRT-PCR and Western blot were performed to assess the expression changes of miR-210, BTG3, apoptosis-related factors and core factors in PI3K/AKT/mTOR pathway. We found that hypoxia induced an apoptosis-dependent death in NSCs. Salidroside exerted bFGF-like effect, as it alleviated hypoxia-induced viability impairment and apoptosis in NSCs. Further studies showed that hypoxia plus salidroside elevated miR-210 expression, and the protective actions of salidroside on hypoxia-modulated death in NSCs were attenuated by miR-210 suppression, while were enhanced by miR-210 overexpression. Besides, BTG3 was negatively regulated by miR-210. Overexpression of BTG3 inhibited the activation of PI3K/AKT/mTOR signaling pathway; of contrast, suppression of BTG3 promoted it. To conclude, this study provide in vitro evidence that salidroside protected NSCs against hypoxia-induced injury by up-regulation of miR-210, which in turn inhibited the expression of BTG3 and activated PI3K/AKT/mTOR signaling pathway.

Neuroprotection afforded by circadian regulation of intracellular glutathione levels: A key role for miRNAs

Circadian rhythms are approximately 24-h oscillations of physiological and behavioral processes that allow us to adapt to daily environmental cycles. Like many other biological functions, cellular redox status and antioxidative defense systems display circadian rhythmicity. In the central nervous system (CNS), glutathione (GSH) is a critical antioxidant because the CNS is extremely vulnerable to oxidative stress; oxidative stress, in turn, causes several fatal diseases, including neurodegenerative diseases. It has long been known that GSH level shows circadian rhythm, although the mechanism underlying GSH rhythm production has not been well-studied. Several lines of recent evidence indicate that the expression of antioxidant genes involved in GSH homeostasis as well as circadian clock genes are regulated by post-transcriptional regulator microRNA (miRNA), indicating that miRNA plays a key role in generating GSH rhythm. Interestingly, several reports have shown that alterations of miRNA expression as well as circadian rhythm have been known to link with various diseases related to oxidative stress. A growing body of evidence implicates a strong correlation between antioxidative defense, circadian rhythm and miRNA function, therefore, their dysfunctions could cause numerous diseases. It is hoped that continued elucidation of the antioxidative defense systems controlled by novel miRNA regulation under circadian control will advance the development of therapeutics for the diseases caused by oxidative stress.

A causal relationship between the neurotherapeutic effects of miR182/7a and decreased expression of PRDM5

BACKGROUND

Spinal cord injury (SCI) is terrible damage resulting in the deficiencies and necrosis of neurology and causes infinite inconvenience to sufferers. The therapy of SCI still meets a larger number of problems. Therefore, the underlying mechanism and novel therapy of acute SCI (ASCI) are urgent to explore.

MATERIALS AND METHODS

The SCI model was established in rats. The expression of miR-182/miR-7a and PRDM5 at mRNA level was detected by quantitative real-time PCR and the protein expression of PRDM5 and c-caspase 3 was assessed by western blotting assays. The apoptosis of spinal cord neurons (SCN) was assessed on flow cytometry. The transfection of cells was performed by Lipofectamine 2000 kit. The relationship between PRDM5 and miR-182/miR-7a was examined by Luciferase assay.

RESULTS

The expression of PRDM5 was up-regulated at either mRNA (2.212 folds) or protein level after SCI in rats, and knockdown of PRDM5 in SCN declined the c-caspase3 expression. In addition, the expression of miR-182 and miR-7a was decreased by 44.6% and 39.3% after SCI in rats. Moreover, the expression of miR-182 and miR-7a were negatively correlated with the level of PRDM5 expression, and the expression of PRDM5 was inhibited due to the increase of miR-182 and/or miR-7a expression. Moreover, both miR-182 and miR-7a could regulate PRDM5 to control SCN apoptosis. According to the BBB score increased 2 folds, the intrathecal injection of miR-182 and miR-7a improved the neurological function of rats.

CONCLUSION

Inhibition of PRDM5 which was apparently negative correlation with miR-182 and miR-7a could suppress the neurons apoptosis to attenuate acute spinal cord injury in rats.

Up-regulation of miR-325-3p suppresses pineal aralkylamine N-acetyltransferase (Aanat) after neonatal hypoxia-ischemia brain injury in rats

Survivors of hypoxic-ischemic brain damage (HIBD), besides impairment of psychomotor development, often develop circadian rhythm disorders, although the underlying mechanisms are largely unknown. Here, we first verified that mRNA and protein expression of pineal aralkylamine N-acetyltransferase (Aanat), a key regulator for melatonin (MT) synthesis, along with MT, were severely impaired after HIBD. In addition, we demonstrated that neonatal HIBD disrupted the circadian rhythmicity of locomotor activities in juvenile rats. Based on bioinformatics analysis of a high throughput screening of miRNA expression changes after HIBD (Ding et al., 2015), we identified one microRNA, miR-325-3p, as a potential candidate responsible for the down regulation of Aanat after HIBD. Luciferase reporter assays demonstrated a specific interaction between miR-325-3p and Aanat mRNA 3'-UTR. miR-325-3p blocked norepinephrine (NE) induced Aanat activation in cultured pinealocytes. In addition, miR-325-3p inhibition partially rescued Aanat induction by NE, which was significantly reduced under oxygen glucose deprivation. By elucidating the role of pineal miR-325-3p on Aanat expression upon injury, our study provides new insights into the pathophysiological mechanisms of circadian dysfunction and potential therapeutic targets after HIBD.

Genetic background-dependent effects of murine micro RNAs on circadian clock function

MicroRNAs (miRs) are important regulators of a wide range of biological processes. Antagomir studies suggest an implication of miR-132 in the functionality of the mammalian circadian clock. miR-212 and miR-132 are tandemly processed from the same transcript and share the same seed region. We found the clock modulator miR-132 and miR-212 to be expressed rhythmically in the central circadian clock. Consequently, mRNAs implicated in circadian functions may likely be targeted by both miRs. To further characterize the circadian role we generated mice with stable deletion of the miR-132/212 locus and compared the circadian behavior of mutant and wild-type control animals on two genetic backgrounds frequently used in chronobiological research, C57BL/6N and 129/Sv. Surprisingly, the wheel-running activity phenotype of miR mutant mice was highly background specific. A prolonged circadian free-running period in constant darkness was found in 129/Sv, but not in C57BL/6N miR-132/212 knockout mice. In contrast, in C57BL/6N, but not in 129/Sv miRNA-132/212 knockout mice a lengthened free-running period was observed in constant light conditions. Furthermore, miR-132/212 knockout mice on 129/Sv background exhibited enhanced photic phase shifts of locomotor activity accompanied by reduced light induction of Period gene transcription in the SCN. This phenotype was absent in miRNA-132/212 knockout mice on a C57BL/6N background. Together, our results reveal a strain and light regimen-specific function of miR-132/212 in the circadian clock machinery suggesting that miR-132 and miR-212 act as background-dependent circadian rhythm modulators.

MicroRNA-182 Regulates Neurite Outgrowth Involving the PTEN/AKT Pathway

MicroRNAs are implicated in neuronal development and maturation. Neuronal maturation, including axon outgrowth and dendrite tree formation, is regulated by complex mechanisms and related to several neurodevelopmental disorders. We demonstrated that one neuron-enriched microRNA, microRNA-182 (miR-182), played a significant role in regulating neuronal axon outgrowth and dendrite tree formation. Overexpression of miR-182 promoted axon outgrowth and complexity of the dendrite tree while also increasing the expression of neurofilament-M and neurofilament-L, which provide structural support for neurite outgrowth. However, a reduction of miR-182 inhibited neurite outgrowth. Furthermore, we showed that miR-182 activated the AKT pathway by increasing AKT phosphorylation on S473 and T308 and inhibiting PTEN activity by increasing phosphorylation on S380. Inhibition of AKT activity with the PI3-K inhibitor LY294002 could downregulate AKT and PTEN phosphorylation and suppress axon outgrowth. In addition, we showed that BCAT2 might be the target of miR-182 that takes part in the regulation of neuronal maturation; blockage of endogenous BCAT2 promotes axon outgrowth and AKT activity. These observations indicate that miR-182 regulates axon outgrowth and dendrite maturation involving activation of the PTEN/AKT pathway.

Systems Biology-Derived Discoveries of Intrinsic Clocks

A systems approach to studying biology uses a variety of mathematical, computational, and engineering tools to holistically understand and model properties of cells, tissues, and organisms. Building from early biochemical, genetic, and physiological studies, systems biology became established through the development of genome-wide methods, high-throughput procedures, modern computational processing power, and bioinformatics. Here, we highlight a variety of systems approaches to the study of biological rhythms that occur with a 24-h period-circadian rhythms. We review how systems methods have helped to elucidate complex behaviors of the circadian clock including temperature compensation, rhythmicity, and robustness. Finally, we explain the contribution of systems biology to the transcription-translation feedback loop and posttranslational oscillator models of circadian rhythms and describe new technologies and "-omics" approaches to understand circadian timekeeping and neurophysiology.

Distinctive sleep problems in children with perinatal moderate or mild hypoxic-ischemia

Extensive studies focus on the cognitive and motor impairments after perinatal hypoxic-ischemia (HI). Sleep problems, although reported to be associated with cerebral palsy (CP), are often overlooked in non-severe HI patients. Here, by investigating the sleep qualities of children with different degrees of HI, we discovered that sleep initiation and maintenance, sleep-related breathing problems, or circadian rhythmic issues were highly associated with children of moderate or mild HI, respectively. Follow-up MRI studies in 2-year old patients showed that periventricular white matter lesions including periventricular leukomalacia (PVL) were prevalent in moderate, but not mild, HI children. In contrast, the occurrence of pineal cysts had a high risk in children with mild HI. Our study provides novel insights into the mechanisms of distinctive sleep problems associated with children of different degrees of HI, and therefore sheds light on the studies of targeted therapeutic treatments for sleep disorders in children who suffer from HI.