Screening the expression of several miRNAs from TaqMan Low Density Array in traumatic brain injury: miR-219a-5p regulates neuronal apoptosis by modulating CCNA2 and CACUL1

Folate-modified liposomes mediate the co-delivery of cisplatin with miR-219a-5p for the targeted treatment of cisplatin-resistant lung cancer

Cisplatin (DDP) resistance, often leading to first-line chemotherapy failure in non-small cell lung cancer (NSCLC), poses a significant challenge. MiR-219a-5p has been reported to enhance the sensitivity of human NSCLC to DDP. However, free miR-219a-5p is prone to degradation by nucleases in the bloodstream, rendering it unstable. In light of this, our study developed an efficient nanodrug delivery system that achieved targeted delivery of DDP and miR-219a-5p by modifying liposomes with folate (FA). Based on the results of material characterization, we successfully constructed a well-dispersed and uniformly sized (approximately 135.8 nm) Lipo@DDP@miR-219a-5p@FA nanodrug. Agarose gel electrophoresis experiments demonstrated that Lipo@DDP@miR-219a-5p@FA exhibited good stability in serum, effectively protecting miR-219a-5p from degradation. Immunofluorescence and flow cytometry experiments revealed that, due to FA modification, Lipo@DDP@miR-219a-5p@FA could specifically bind to FA receptors on the surface of tumor cells (A549), thus enhancing drug internalization efficiency. Safety evaluations conducted in vitro demonstrated that Lipo@DDP@miR-219a-5p@FA exhibited no significant toxicity to non-cancer cells (BEAS-2B) and displayed excellent blood compatibility. Cellular functional experiments, apoptosis assays, and western blot demonstrated that Lipo@DDP@miR-219a-5p@FA effectively reversed DDP resistance in A549 cells, inhibited cell proliferation and migration, and further promoted apoptosis. In summary, the Lipo@DDP@miR-219a-5p@FA nanodrug, through specific targeting of cancer cells and reducing their resistance to DDP, significantly enhanced the anti-NSCLC effects of DDP in vitro, providing a promising therapeutic option for the clinical treatment of NSCLC.

Non-Coding RNAs in Human Cancer and Other Diseases: Overview of the Diagnostic Potential

Non-coding RNAs (ncRNAs) are abundant single-stranded RNA molecules in human cells, involved in various cellular processes ranging from DNA replication and mRNA translation regulation to genome stability defense. MicroRNAs are multifunctional ncRNA molecules of 18-24 nt in length, involved in gene silencing through base-pair complementary binding to target mRNA transcripts. piwi-interacting RNAs are an animal-specific class of small ncRNAs sized 26-31 nt, responsible for the defense of genome stability via the epigenetic and post-transcriptional silencing of transposable elements. Long non-coding RNAs are ncRNA molecules defined as transcripts of more than 200 nucleotides, their function depending on localization, and varying from the regulation of cell differentiation and development to the regulation of telomere-specific heterochromatin modifications. The current review provides recent data on the several forms of small and long non-coding RNA's potential to act as diagnostic, prognostic or therapeutic target for various human diseases.

MicroRNAs as Potential Biomarkers of Post-Traumatic Epileptogenesis: A Systematic Review

Structural or post-traumatic epilepsy often develops after brain tissue damage caused by traumatic brain injury, stroke, infectious diseases of the brain, etc. Most often, between the initiating event and epilepsy, there is a period without seizures-a latent period. At this time, the process of restructuring of neural networks begins, leading to the formation of epileptiform activity, called epileptogenesis. The prediction of the development of the epileptogenic process is currently an urgent and difficult task. MicroRNAs are inexpensive and minimally invasive biomarkers of biological and pathological processes. The aim of this study is to evaluate the predictive ability of microRNAs to detect the risk of epileptogenesis. In this study, we conducted a systematic search on the MDPI, PubMed, ScienceDirect, and Web of Science platforms. We analyzed publications that studied the aberrant expression of circulating microRNAs in epilepsy, traumatic brain injury, and ischemic stroke in order to search for microRNAs-potential biomarkers for predicting epileptogenesis. Thus, 31 manuscripts examining biomarkers of epilepsy, 19 manuscripts examining biomarkers of traumatic brain injury, and 48 manuscripts examining biomarkers of ischemic stroke based on circulating miRNAs were analyzed. Three miRNAs were studied: miR-21, miR-181a, and miR-155. The findings showed that miR-21 and miR-155 are associated with cell proliferation and apoptosis, and miR-181a is associated with protein modifications. These miRNAs are not strictly specific, but they are involved in processes that may be indirectly associated with epileptogenesis. Also, these microRNAs may be of interest when they are studied in a cohort with each other and with other microRNAs. To further study the microRNA-based biomarkers of epileptogenesis, many factors must be taken into account: the time of sampling, the type of biological fluid, and other nuances. Currently, there is a need for more in-depth and prolonged studies of epileptogenesis.

Non-coding RNAs and Exosomal Non-coding RNAs in Traumatic Brain Injury: the Small Player with Big Actions

Nowadays, there is an increasing concern regarding traumatic brain injury (TBI) worldwide since substantial morbidity is observed after it, and the long-term consequences that are not yet fully recognized. A number of cellular pathways related to the secondary injury in brain have been identified, including free radical production (owing to mitochondrial dysfunction), excitotoxicity (regulated by excitatory neurotransmitters), apoptosis, and neuroinflammatory responses (as a result of activation of the immune system and central nervous system). In this context, non-coding RNAs (ncRNAs) maintain a fundamental contribution to post-transcriptional regulation. It has been shown that mammalian brains express high levels of ncRNAs that are involved in several brain physiological processes. Furthermore, altered levels of ncRNA expression have been found in those with traumatic as well non-traumatic brain injuries. The current review highlights the primary molecular mechanisms participated in TBI that describes the latest and novel results about changes and role of ncRNAs in TBI in both clinical and experimental research.

Traumatic MicroRNAs: Deconvolving the Signal After Severe Traumatic Brain Injury

History of traumatic brain injury (TBI) represents a significant risk factor for development of dementia and neurodegenerative disorders in later life. While histopathological sequelae and neurological diagnostics of TBI are well defined, the molecular events linking the post-TBI signaling and neurodegenerative cascades remain unknown. It is not only due to the brain's inaccessibility to direct molecular analysis but also due to the lack of well-defined and highly informative peripheral biomarkers. MicroRNAs (miRNAs) in blood are promising candidates to address this gap. Using integrative bioinformatics pipeline including miRNA:target identification, pathway enrichment, and protein-protein interactions analysis we identified set of genes, interacting proteins, and pathways that are connected to previously reported peripheral miRNAs, deregulated following severe traumatic brain injury (sTBI) in humans. This meta-analysis revealed a spectrum of genes closely related to critical biological processes, such as neuroregeneration including axon guidance and neurite outgrowth, neurotransmission, inflammation, proliferation, apoptosis, cell adhesion, and response to DNA damage. More importantly, we have identified molecular pathways associated with neurodegenerative conditions, including Alzheimer's and Parkinson's diseases, based on purely peripheral markers. The pathway signature after acute sTBI is similar to the one observed in chronic neurodegenerative conditions, which implicates a link between the post-sTBI signaling and neurodegeneration. Identified key hub interacting proteins represent a group of novel candidates for potential therapeutic targets or biomarkers.

An Overview on the Use of miRNAs as Possible Forensic Biomarkers for the Diagnosis of Traumatic Brain Injury

Determining the cause of death is one of the main goals of forensic pathology. However, conditions can occur in which common approaches—external inspection, autopsy, histology, etc.—might not be conclusive. With the advancement of molecular biology, several investigative techniques have been developed over the years, and the application as approaches complementary to routine procedures has proved useful in these cases. In this context, microRNA (miRNA) profiling has attracted increasing interest due to these molecules’ ability to regulate physiological and pathological processes. The evidence of differential miRNA expression in both animal models and human samples of traumatic brain injury (TBI) has laid the basis for comprehension of the underlying pathophysiological mechanisms, thus allowing us to identify some of them as possible TBI diagnostic biomarkers. The present narrative review aims to explore the primary miRNAs involved in the mechanisms underlying TBI, which could be considered for future evaluation as possible markers in a post mortem setting.

Real-Time PCR Quantification of 87 miRNAs from Cerebrospinal Fluid: miRNA Dynamics and Association with Extracellular Vesicles after Severe Traumatic Brain Injury

Severe traumatic brain injury (sTBI) is an intracranial damage triggered by external force, most commonly due to falls and traffic accidents. The initial brain injury can progress into a secondary injury involving numerous pathophysiological processes. The resulting sTBI dynamics makes the treatment challenging and prompts the improved understanding of underlying intracranial processes. Here, we analysed how extracellular microRNAs (miRNAs) are affected by sTBI. We collected thirty-five cerebrospinal fluids (CSF) from five sTBI patients during twelve days (d) after the injury and combined them into d1-2, d3-4, d5-6 and d7-12 CSF pools. After miRNA isolation and cDNA synthesis with added quantification spike-ins, we applied a real-time PCR-array targeting 87 miRNAs. We detected all of the targeted miRNAs, with totals ranging from several nanograms to less than a femtogram, with the highest levels found at d1-2 followed by decreasing levels in later CSF pools. The most abundant miRNAs were miR-451a, miR-16-5p, miR-144-3p, miR-20a-5p, let-7b-5p, miR-15a-5p, and miR-21-5p. After separating CSF by size-exclusion chromatography, most miRNAs were associated with free proteins, while miR-142-3p, miR-204-5p, and miR-223-3p were identified as the cargo of CD81-enriched extracellular vesicles, as characterised by immunodetection and tunable resistive pulse sensing. Our results indicate that miRNAs might be informative about both brain tissue damage and recovery after sTBI.

Circulating Extracellular Vesicles and Particles Derived From Adipocytes: The Potential Role in Spreading MicroRNAs Associated With Cellular Senescence

Aging is associated with adipose tissue dysfunction and is recognized as a risk factor for shortened life span. Considering that in vitro findings have shown the involvement of microRNA in extracellular vesicles and particles (EVPs) on senescence, we hypothesized that circulating EVPs derived from adipocytes can be involved in the aging process via their microRNA cargo. We aimed to determine the microRNA profiles of circulating EVPs derived from adipocytes (FABP4+) from aged and young adult animals and to perform in silico prediction of their downstream signaling effects. Plasma was obtained from Wistar rats (3 and 21 months old), and adipocyte-derived EVPs were isolated using the commercially available kit. Fatty acid-binding protein 4 (FABP4) was used for adipocyte-derived EVPs isolation; microRNA isolation and microarray expression analysis were performed. The analysis revealed 728 miRNAs, 32 were differentially between groups (p < 0.05; fold change ≥ |1.1|), of which 15 miRNAs were upregulated and 17 were downregulated in circulating EVPs from aged animals compared to young adults. A conservative filter was applied, and 18 microRNAs had experimentally validated and highly conserved predicted mRNA targets, with a total of 2,228 mRNAs. Canonical pathways, disease and functions, and upstream regulator analyses were performed using IPA-QIAGEN, allowing a global and interconnected evaluation. IPA categories impacted negatively were cell cycle, cellular development, cellular growth and proliferation, and tissue development, while those impacted positively were “digestive system cancer” and “endocrine gland tumor.” Interestingly, the upregulated miR-15-5p targets several cyclins, such as CCND1 and CCND2, and miR-24-3p seems to target CDK4 (cyclin-dependent kinase 4); then potentially inhibiting their expression, both miRNAs can induce a negative regulation of cell cycle progression. In contrast, silencing of negative cell cycle checkpoint regulators, such as p21 and p16, can be predicted, which can induce impairment in response to genotoxic stressors. In addition, predicted targets, such as SMAD family members, seem to be involved in the positive control of digestive and endocrine tumors. Taken together, this exploratory study indicates that miRNA signature in circulating adipocyte-derived EVPs may be involved with the double-edged sword of cellular senescence, including irreversible proliferation arrest and tissue-dependent cancer, and seems to be suitable for further validation and confirmatory studies.

Serum MicroRNA Expression Patterns in Subjects After the 5-km Exercise Are Strongly Associated With Cardiovascular Adaptation

Circulating microRNAs (miRNAs) have been reported dysregulated during exercise. However, the changes of specific serum miRNAs during the 5-km run test with intensity of 51–52% maximum oxygen uptake (V̇O₂max) and their association with traditional cardiovascular-related indicators remain well-characterized. Levels of miR-1, miR-21, miR-146a, miR-155, miR-181, and miR-210 were detected in 120 young subjects before and after the exercise training by quantitative reverse-transcription PCR (RT-qPCR). Besides, the levels of cardiac troponin I (cTNI), myoglobin (Myo), creatine kinase (CK), creatine kinase-MB (CK-MB), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), ischemia-modified albumin (IMA), interleukin-6 (IL-6), and C-reactive protein (CRP) were measured and the correlation between levels of serum miRNAs and biochemical parameters was also analyzed. Compared with resting state, the serum levels of miR-1, miR-146a, miR-155, miR-181, and miR-210 were significantly increased after exercise training. Serum levels of miR-146a, miR-155, and miR-210 after exercise training were positively correlated with Myo, CK-MB, and LDH, respectively, while miR-1, miR-146a, miR-181, and miR-155 were positively correlated with the levels of IL-6. Additionally, all the five miRNAs were negatively correlated with IMA levels. The multivariate logistic regression analysis showed that high levels of miR-146a, AST, LDH, and IL-6 in serum were risk factors, while low IMA contents were a protective factor for cardiovascular adaptation during exercise. In conclusion, the dynamic changes of miRNAs under the condition of the 5-km continuous running contribute to the adaptive regulation of the cardiovascular function of the body.

The Clinical Use of Serum Biomarkers in Traumatic Brain Injury: A Systematic Review Stratified by Injury Severity

BACKGROUND

Serum biomarkers have gained significant popularity as an adjunctive measure in the evaluation and prognostication of traumatic brain injury (TBI). However, a concise and clinically oriented report of the major markers in function of TBI severity is lacking. This systematic review aims to report current data on the diagnostic and prognostic utility of blood-based biomarkers across the spectrum of TBI.

METHODS

A literature search of the PubMed/Medline electronic database was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We excluded systematic reviews and meta-analyses that did not provide novel data. The American College of Cardiology/American Heart Association criteria were used to assess levels of evidence.

RESULTS

An initial 1463 studies were identified. In total, 115 full-text articles reporting on 94 distinct biomarkers met the inclusion criteria. Glasgow Coma Scale scores, computed tomography/magnetic resonance imaging abnormalities, and injury severity scores were the most used clinical diagnostic variables. Glasgow Outcome Scores and 1-, 3-, and 6-month mortality were the most used clinical prognostic variables. Several biomarkers significantly correlated with these variables and had statistically significant different levels in TBI subjects when compared with healthy, orthopedic, and polytrauma controls. The biomarkers also displayed significant variability across mild, moderate, and severe TBI categories, as well as in concussion cases.

CONCLUSIONS

This review summarizes existing high-quality evidence that supports the use of severity-specific biomarkers in the diagnostic and prognostic evaluation of TBI. These data can be used as a launching platform for the validation of upcoming clinical studies.

Selenium-deficient diet induces necroptosis in the pig brain by activating TNFR1 via mir-29a-3p

Selenium (Se) deficiency is one of the crucial factors related to nervous system disease and necroptosis. MicroRNAs (miRNAs) play vital roles in regulating necroptosis. However, the mechanism of Se deficiency-induced necroptosis in the pig brain tissue and the role that miRNAs play in this process are unclear. Therefore, in this study, in vitro and pig models of Se deficiency were replicated, and electron microscopy, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot assays were performed. The results showed that brain cells typically undergo necrotic changes, and that Se deficiency suppresses mir-29a-3p, which increases the levels of TNFRSF1A (TNFR1). Subsequently, a distinct increase in the necroptosis markers (RIPK1, RIPK3, and MLKL) and an evident decrease in caspase 8 was observed. And the expression of 10 selenoproteins was decreased. Moreover, the in vitro experiments showed that the expression of mir-29a-3p decreased as the Se content in the medium decreased and the application of an mir-29a-3p inhibitor increased the number of necrotic cells and the accumulation of ROS, and these effects were inhibited by necrostatin-1 (Nec-1) and N-acetyl-cysteine (NAC), respectively. Taken together, we proved that Se deficiency induced necroptosis both in vitro and in vivo through the targeted regulation of TNFR1 by mir-29a-3p in the pig brain.

Biomarkers for posttraumatic epilepsy

A biomarker is a characteristic that can be objectively measured as an indicator of normal biologic processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions. Biomarker modalities include molecular, histologic, radiographic, or physiologic characteristics. To improve the understanding and use of biomarker terminology in biomedical research, clinical practice, and medical product development, the Food and Drug Administration (FDA)-National Institutes of Health (NIH) Joint Leadership Council developed the BEST Resource (Biomarkers, EndpointS, and other Tools). The seven BEST biomarker categories include the following: (a) susceptibility/risk biomarkers, (b) diagnostic biomarkers, (c) monitoring biomarkers, (d) prognostic biomarkers, (e) predictive biomarkers, (f) pharmacodynamic/response biomarkers, and (g) safety biomarkers. We hypothesize some potential overlap between the reported biomarkers of traumatic brain injury (TBI), epilepsy, and posttraumatic epilepsy (PTE). Here, we tested this hypothesis by reviewing studies focusing on biomarker discovery for posttraumatic epileptogenesis and epilepsy. The biomarker modalities reviewed here include plasma/serum and cerebrospinal fluid molecular biomarkers, imaging biomarkers, and electrophysiologic biomarkers. Most of the reported biomarkers have an area under the receiver operating characteristic curve greater than 0.800, suggesting both high sensitivity and high specificity. Our results revealed little overlap in the biomarker candidates between TBI, epilepsy, and PTE. In addition to using single parameters as biomarkers, machine learning approaches have highlighted the potential for utilizing patterns of markers as biomarkers. Although published data suggest the possibility of identifying biomarkers for PTE, we are still in the early phase of the development curve. Many of the seven biomarker categories lack PTE-related biomarkers. Thus, further exploration using proper, statistically powered, and standardized study designs with validation cohorts, and by developing and applying novel analytical methods, is needed for PTE biomarker discovery.

N6-methyladenosine RNA modification: A promising regulator in central nervous system injury

In addition to DNA methylation, reversible epigenetic modification occurring in RNA has been discovered recently. The most abundant type of RNA methylation is N6-methyladenosine (m6A) modification, which is dynamically regulated by methylases ("writers"), demethylases ("erasers") and m6A-binding proteins ("readers"). As an essential posttranscriptional regulator, m6A can control mRNA splicing, processing, stability, export and translation. Recent studies have revealed that m6A modification has the strongest tissue specificity for brain tissue and plays crucial roles in central nervous system (CNS) injures by affecting its downstream target genes or non-coding RNAs. This review focuses on the expression and function of m6A regulatory proteins in CNS trauma in vitro and in vivo. We also highlight the latest insights into the molecular mechanisms of pathological damage in the CNS. Understanding m6A dynamics, functions, and machinery will yield an opportunity for designing and developing novel therapeutic agents for CNS injuries.

circMTO1 sponges microRNA-219a-5p to enhance gallbladder cancer progression via the TGF-β/Smad and EGFR pathways

Circular mitochondrial translation optimization 1 homologue (circMTO1) has been reported to regulate the tumorigenesis of different types of cancer; however, the role of circMTO1 in gallbladder cancer (GBC) remains unknown. The present study aimed to identify the potential miRNAs and target genes of circMTO1 during GBC progression, and clarify the regulatory mechanism between circMTO1 and miRNAs or target genes. The present study performed MTT and Transwell assays, and Annexin V staining to assess cell viability, migration and apoptosis, respectively. In addition, a lymphatic vessel formation assay was performed to assess tube formation of human dermal lymphatic endothelial cells (HDLECs), and GBC-SD and NOZ cells. The results demonstrated that circMTO1 knockdown significantly attenuated the viability and migration of GBC cells and tube formation of HDLECs, and promoted apoptosis, indicating a tumor-promoting role of circMTO1. In addition, transfection with microRNA (miRNA/miR)-219a-5p inhibitor rescued short hairpin RNA-circMTO1-inhibited tumorigenesis of GBC cells, suggesting that miR-219a-5p acts as a downstream effector for circMTO1. Mechanistically, transfection with miR-219a-5p mimic suppressed the expression levels of Smad2/4 and epidermal growth factor receptor. Analysis of The Cancer Genome Atlas datasets revealed that circMTO1 expression was associated with overall survival and the stage of patients with GBC. Taken together, the results of the present study provide novel insight for the role of circMTO1-induced GBC tumorigenesis via regulation of miR-219a-5p expression.

Plasma miR-9-3p and miR-136-3p as Potential Novel Diagnostic Biomarkers for Experimental and Human Mild Traumatic Brain Injury

Noninvasive, affordable circulating biomarkers for difficult-to-diagnose mild traumatic brain injury (mTBI) are an unmet medical need. Although blood microRNA (miRNA) levels are reportedly altered after traumatic brain injury (TBI), their diagnostic potential for mTBI remains inconclusive. We hypothesized that acutely altered plasma miRNAs could serve as diagnostic biomarkers both in the lateral fluid percussion injury (FPI) model and clinical mTBI. We performed plasma small RNA-sequencing from adult male Sprague-Dawley rats (n = 31) at 2 days post-TBI, followed by polymerase chain reaction (PCR)-based validation of selected candidates. miR-9a-3p, miR-136-3p, and miR-434-3p were identified as the most promising candidates at 2 days after lateral FPI. Digital droplet PCR (ddPCR) revealed 4.2-, 2.8-, and 4.6-fold elevations in miR-9a-3p, miR-136-3p, and miR-434-3p levels (p < 0.01 for all), respectively, distinguishing rats with mTBI from naïve rats with 100% sensitivity and specificity. DdPCR further identified a subpopulation of mTBI patients with plasma miR-9-3p (n = 7/15) and miR-136-3p (n = 5/15) levels higher than one standard deviation above the control mean at <2 days postinjury. In sTBI patients, plasma miR-9-3p levels were 6.5- and 9.2-fold in comparison to the mTBI and control groups, respectively. Thus, plasma miR-9-3p and miR-136-3p were identified as promising biomarker candidates for mTBI requiring further evaluation in a larger patient population.

miR-142-3p Expression Is Predictive for Severe Traumatic Brain Injury (TBI) in Trauma Patients

BACKGROUND

Predictive biomarkers in biofluids are the most commonly used diagnostic method, but established markers in trauma diagnostics lack accuracy. This study investigates promising microRNAs (miRNA) released from affected tissue after severe trauma that have predictive values for the effects of the injury.

METHODS

A retrospective analysis of prospectively collected data and blood samples of n = 33 trauma patients (ISS ≥ 16) is provided. Levels of miR-9-5p, -124-3p, -142-3p, -219a-5p, -338-3p and -423-3p in severely injured patients (PT) without traumatic brain injury (TBI) or with severe TBI (PT + TBI) and patients with isolated TBI (isTBI) were measured within 6 h after trauma.

RESULTS

The highest miR-423-3p expression was detected in patients with severe isTBI, followed by patients with PT + TBI, and lowest levels were found in PT patients without TBI (2^-∆∆Ct, p = 0.009). A positive correlation between miR-423-3p level and increasing AIS_head (p = 0.001) and risk of mortality (RISC II, p = 0.062) in trauma patients (n = 33) was found. ROC analysis of miR-423-3p levels revealed them as statistically significant to predict the severity of brain injury in trauma patients (p = 0.006). miR-124-3p was only found in patients with severe TBI, miR-338-3p was shown in all trauma groups. miR-9-5p, miR-142-3p and miR-219a-5p could not be detected in any of the four groups.

CONCLUSION

miR-423-3p expression is significantly elevated after isolated traumatic brain injury and predictable for severe TBI in the first hours after trauma. miR-423-3p could represent a promising new biomarker to identify severe isolated TBI.

Regulatory noncoding RNAs and the major histocompatibility complex

The Major Histocompatibility Complex (MHC) is a 4 Mbp genomic region located on the short arm of chromosome 6. The MHC region contains many key immune-related genes such as Human Leukocyte Antigens (HLAs). There has been a growing realization that, apart from MHC encoded proteins, RNAs derived from noncoding regions of the MHC-specifically microRNAs (miRNAs) and long noncoding RNAs (lncRNAs)-play a significant role in cellular regulation. Furthermore, regulatory noncoding RNAs (ncRNAs) derived from other parts of the genome fine-tune the expression of many immune-related MHC proteins. Although the field of ncRNAs of the MHC is a research area that is still in its infancy, ncRNA regulation of MHC genes has already been shown to be vital for immune function, healthy pregnancy and cellular homeostasis. Dysregulation of this intricate network of ncRNAs can lead to serious perturbations in homeostasis and subsequent disease.

Bioinformatic analysis of brain-specific miRNAs for identification of candidate traumatic brain injury blood biomarkers

BACKGROUND

Detection of brain-specific miRNAs in the peripheral blood could serve as a surrogate marker of traumatic brain injury (TBI). Here, we systematically identified brain-enriched miRNAs, and tested their utility as TBI biomarkers in the acute phase of care.

METHODS

Publically available microarray data generated from 29 postmortem human tissues were used to rank 1,364 miRNAs in terms of their degree of brain-specific expression. Levels of the top six ranked miRNAs were then prospectively measured in serum samples collected from 10 Patients with TBI at hospital admission, as well as from 10 controls.

RESULTS

The top six miRNAs identified in our analysis (miR-124-3p, miR-219a-5p, miR-9-5p, miR-9-3p, miR-137, and miR-128-3p) were enriched 70 to 320-fold in brain relative to other tissues, and exhibited dramatically greater brain specificity compared to several miRNAs previously proposed as biomarkers. Furthermore, their levels were elevated in serum from patients with TBI compared to controls, and could collectively discriminate between groups with 90% sensitivity and 100% specificity. Interestingly, subsequent informatic pathway analysis revealed that their target transcripts were enriched for components of signaling pathways active in peripheral organs involved in common post-TBI complications.

CONCLUSIONS

The six candidate miRNAs identified in this preliminary study have promise as blood biomarkers of TBI, and could also be molecular contributors to systemic physiologic changes commonly observed post-injury.

Upregulation of miR-219a-5p Decreases Cerebral Ischemia/Reperfusion Injury In Vitro by Targeting Pde4d

BACKGROUND

Ischemic stroke is the leading cause of disability and death globally. Micro-RNAs (miRNAs) have been reported to play important roles in the development and pathogenesis of the nervous system. However, the exact function and mechanism of miRNAs have not been fully elucidated about brain damage caused by cerebral ischemia/reperfusion (I/R).

METHODS

In this study, we explored the neuroprotective effects of miR-219a-5p on brain using an in vitro ischemia model (mouse neuroblastoma N2a cells treated with oxyglucose deprivation and reperfusion), and in vivo cerebral I/R model in mice. Western blot assay and Reverse Transcription-Polymerase Chain Reaction were used to check the expression of molecules involved. Flow cytometry and cholecystokinin were used to examine cell apoptosis, respectively.

RESULTS

Our research shows that miR-219a-5p gradually decreases in cerebral I/R models in vivo and in vitro. In vitro I/R, we find that miR-219a-5p mimics provided evidently protection for cerebral I/R damage, as shown by increased cell viability and decreased the release of LDH and cell apoptosis. Mechanically, our findings indicate that miR-219a-5p binds to cAMP specific 3', 5'-cyclic phosphodiesterase 4D (PDE4D) mRNA in the 3'-UTR region, which subsequently leads to a decrease in Pde4d expression in I/R N2a cells.

CONCLUSIONS

Our results provide new ideas for the study of the mechanism of cerebral ischemia/reperfusion injury, and lay the foundation for further research on the treatment of brain I/R injury. Upregulation of miR-219a-5p decreases cerebral ischemia/reperfusion injury by targeting Pde4d in vitro.

The many (sur)faces of B cells

This issue of the Biomedical Journal is dedicated to the latest findings concerning the complex development and functions of B lymphocytes, including their origins during embryogenesis, their meticulous control by the CD22 receptor and different types of T cells, as well as the immunosuppressive abilities of certain B cell subsets. Furthermore, we learn about the complicated genetic background of a rare cardiac disease, the surgical outcomes of pure conus medullaris syndrome and occurrences of tuberculous spondylitis after percutaneous vertebroplasty. Finally, we discover that brain waves could very well be used for biometric authentication and that diffusion imaging displays good reproducibility through a spectrum of spatial resolutions.