Total abdominal irradiation exposure impairs cognitive function involving miR-34a-5p/BDNF axis

Radio-miRs: a comprehensive view of radioresistance-related microRNAs

Radiotherapy is a key treatment option for a wide variety of human tumors, employed either alone or alongside with other therapeutic interventions. Radiotherapy uses high-energy particles to destroy tumor cells, blocking their ability to divide and proliferate. The effectiveness of radiotherapy is due to genetic and epigenetic factors that determine how tumor cells respond to ionizing radiation. These factors contribute to the establishment of resistance to radiotherapy, which increases the risk of poor clinical prognosis of patients. Although the mechanisms by which tumor cells induce radioresistance are unclear, evidence points out several contributing factors including the overexpression of DNA repair systems, increased levels of reactive oxygen species, alterations in the tumor microenvironment, and enrichment of cancer stem cell populations. In this context, dysregulation of microRNAs or miRNAs, critical regulators of gene expression, may influence how tumors respond to radiation. There is increasing evidence that miRNAs may act as sensitizers or enhancers of radioresistance, regulating key processes such as the DNA damage response and the cell death signaling pathway. Furthermore, expression and activity of miRNAs have shown informative value in overcoming radiotherapy and long-term radiotoxicity, revealing their potential as biomarkers. In this review, we will discuss the molecular mechanisms associated with the response to radiotherapy and highlight the central role of miRNAs in regulating the molecular mechanisms responsible for cellular radioresistance. We will also review radio-miRs, radiotherapy-related miRNAs, either as sensitizers or enhancers of radioresistance that hold promise as biomarkers or pharmacological targets to sensitize radioresistant cells.

BDNF Modulation by microRNAs: An Update on the Experimental Evidence

MicroRNAs can interfere with protein function by suppressing their messenger RNA translation or the synthesis of its related factors. The function of brain-derived neurotrophic factor (BDNF) is essential to the proper formation and function of the nervous system and is seen to be regulated by many microRNAs. However, understanding how microRNAs influence BDNF actions within cells requires a wider comprehension of their integrative regulatory mechanisms. Aim: In this literature review, we have synthesized the evidence of microRNA regulation on BDNF in cells and tissues, and provided an analytical discussion about direct and indirect mechanisms that appeared to be involved in BDNF regulation by microRNAs. Methods: Searches were conducted on PubMed.gov using the terms "BDNF" AND "MicroRNA" and "brain-derived neurotrophic factor" AND "MicroRNA", updated on 1 September 2023. Papers without open access were requested from the authors. One hundred and seventy-one papers were included for review and discussion. Results and Discussion: The local regulation of BDNF by microRNAs involves a complex interaction between a series of microRNAs with target proteins that can either inhibit or enhance BDNF expression, at the core of cell metabolism. Therefore, understanding this homeostatic balance provides resources for the future development of vector-delivery-based therapies for the neuroprotective effects of BDNF.

Pelvic irradiation induces behavioural and neuronal damage through gut dysbiosis in a rat model

Radiation exposure can cause gut dysbiosis and there is a positive correlation between gut microbial imbalance and radiation-induced side effects in cancer patients. However, the influence of radiation on the gut-brain axis (GBA) and its neurological consequences are not well understood. Therefore, this study aimed to investigate the impact of pelvic irradiation on gut microbiota and the brain. Sprague Dawley rats were irradiated with a single dose of 6 Gy, and faecal samples were collected at different time points (7 and 12-days post-irradiation) for microbial analysis. Behavioural, histological, and gene expression analysis were performed to assess the effect of microbial dysbiosis on the brain. The findings indicated alterations in microbial diversity, disrupted intestinal morphology and integrity, neuronal death-related brain changes, neuroinflammation and reduced locomotor activity. Hippocampal gene expression analysis also showed a reduced expression of neural plasticity-related genes. Overall, this study demonstrated that pelvic irradiation affects gut microbiota, intestinal morphology, integrity, brain neuronal maturation, neural plasticity gene expression, and behaviour.

Marasmius androsaceus mitigates depression-exacerbated intestinal radiation injuries through reprogramming hippocampal miRNA expression

INTRODUCTION

Cancer patients commonly experience high levels of psychological stress, which poses significant risks to their well-being. Radiotherapy is a primary treatment modality for cancer; however, it often leads to intestinal injuries in these patients. Nevertheless, the impact of mental stress on radiotherapy-intertwined complications remains unclear.

METHODS

To induce intestinal injury, we employed total abdominal irradiation in our experimental model. We conducted high-throughput sequencing to analyze the expression profile of miRNAs in the hippocampus.

RESULTS

We observed that mice with depression exhibited more severe intestinal injuries following total abdominal irradiation. Remarkably, oral administration of Marasmius androsaceus not only alleviated the depressive phenotype but also mitigated radiation-induced intestinal toxicity. Notably, this radioprotective effect was not observed in mice without depression. Depression disrupted the hippocampal miRNA expression profile in mice subjected to local irradiation of the abdomen, leading to the accumulation of miR-139-5p and miR-184-3p in the hippocampus, serum, and small intestine tissues. However, treatment with Marasmius androsaceus reprogrammed the miRNA expression signature in mice with depression. Furthermore, intravenous injection of antagomirs targeting miR-139-5p and miR-184-3p ameliorated depression, up-regulated Spn expression, reduced radiation enteritis, and improved the integrity of the small intestine in irradiated mice.

CONCLUSION

Our findings demonstrate the efficacy of Marasmius androsaceus, a small mushroom, in alleviating depression-aggravated intestinal toxicity following radiotherapy by reprogramming hippocampal miRNA expression.

Sexually dimorphic extracellular vesicle responses after chronic spinal cord injury are associated with neuroinflammation and neurodegeneration in the aged brain

BACKGROUND

Medical advances have made it increasingly possible for spinal cord injury (SCI) survivors to survive decades after the insult. But how SCI affects aging changes and aging impacts the injury process have received limited attention. Extracellular vesicles (EVs) are recognized as critical mediators of neuroinflammation after CNS injury, including at a distance from the lesion site. We have previously shown that SCI in young male mice leads to robust changes in plasma EV count and microRNA (miR) content. Here, our goal was to investigate the impact of biological sex and aging on EVs and brain after SCI.

METHODS

Young adult age-matched male and female C57BL/6 mice were subjected to SCI. At 19 months post-injury, total plasma EVs were isolated by ultracentrifugation and characterized by nanoparticle tracking analysis (NTA). EVs miR cargo was examined using the Fireplex® assay. The transcriptional changes in the brain were assessed by a NanoString nCounter Neuropathology panel and validated by Western blot (WB) and flow cytometry (FC). A battery of behavioral tests was performed for assessment of neurological function.

RESULTS

Transcriptomic changes showed a high number of changes between sham and those with SCI. Sex-specific changes were found in transcription networks related to disease association, activated microglia, and vesicle trafficking. FC showed higher microglia and myeloid counts in the injured tissue of SCI/Female compared to their male counterparts, along with higher microglial production of ROS in both injured site and the brain. In the latter, increased levels of TNF and mitochondrial membrane potential were seen in microglia from SCI/Female. WB and NTA revealed that EV markers are elevated in the plasma of SCI/Male. Particle concentration in the cortex increased after injury, with SCI/Female showing higher counts than SCI/Male. EVs cargo analysis revealed changes in miR content related to injury and sex. Behavioral testing confirmed impairment of cognition and depression at chronic time points after SCI in both sexes, without significant differences between males and females.

CONCLUSIONS

Our study is the first to show sexually dimorphic changes in brain after very long-term SCI and supports a potential sex-dependent EV-mediated mechanism that contributes to SCI-induced brain changes.

Advances in the study of the molecular biological mechanisms of radiation-induced brain injury

Radiation therapy is one of the most commonly used treatments for head and neck cancers, but it often leads to radiation-induced brain injury. Patients with radiation-induced brain injury have a poorer quality of life, and no effective treatments are available. The pathogenesis of this condition is unknown. This review summarizes the molecular biological mechanism of radiation-induced brain injury and provides research directions for future studies. The molecular mechanisms of radiation-induced brain injury are diverse and complex. Radiation-induced chronic neuroinflammation, destruction of the blood-brain barrier, oxidative stress, neuronal damage, and physiopathological responses caused by specific exosome secretion lead to radiation-induced brain injury.

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

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

Cadmium induces ferroptosis and apoptosis by modulating miR-34a-5p/Sirt1axis in PC12 cells

Cadmium (Cd) is a potent neurotoxic metal present in the environment and food. In this study, CdCl₂ (2 or 4 μM) induced cytotoxicity and neurotoxicity in PC12 cells, causing decreases in cell viability and NEP protein expression and increase in p-tau protein expression. For the first time, CdCl₂ -initiated injury was found to result from the induction of not only apoptosis but also ferroptosis, as evidenced by the increased iron content, ROS production, and mitochondrial membrane potential along with changes in the expressions of iron death-related genes (FTH1, GPX4, ASCL4, PTGS2, and NOX1) and levels of caspase9, Bax, and Bcl-2 proteins. The molecular mechanisms leading to apoptosis and ferroptosis at least included the participation of the miR-34a-5p/Sirt1 axis, in which miR-34a-5p promoted CdCl₂ -induced neurotoxicity through targeting Sirt1. Knocking out miR-34a-5p attenuated CdCl₂ -induced damage of PC12 cells, cytotoxicity and neurotoxicity. This research provides the underlying molecular mechanisms of CdCl₂ -induced damage and asserts the role of miRNAs as critical regulators.

The G to A transformation of rs4702 polymorphism in 3'UTR of FURIN reduced the risk of radiotherapy-induced cognitive impairment in glioma patients

The G allele of rs4702 polymorphism has been reported to reduce the production of mature BDNF and FURIN, both of which were closely associated with cognitive functions. Real‐time PCR, ELISA and luciferase assay were performed to explore the interactions between miR‐338‐3p, FURIN and BDNF. T‐RFLP was used to assess the intestinal flora in the stool samples of glioma patients after radiotherapy. We grouped the 106 glioma patients recruited according to the rs4702 polymorphism. The results showed no obvious correlation between rs4702 polymorphism and the expression of miR‐338‐3p. However, rs4702‐A was associated with increased expression of FURIN and BDNF in the serum and PBMC of glioma patients after radiotherapy. Besides, the study found that rs4702‐A was remarkably associated with increased enterotype I and decreased enterotype III in the stool of glioma patients after radiotherapy. Rs4702‐A was also proved to be closely associated with increased MMSE, role functioning and social functioning at three months after radiotherapy. Furthermore, miR‐338‐3p repressed the expression of FURIN‐G. Compared with G allele, the presence of A allele of rs4702 polymorphism in FURIN could obstruct the suppressive effect of miR‐338‐3p upon the expression of FURIN and BDNF in intestinal flora. Therefore, the carriers of A allele will be challenged with less risk of radiotherapy‐induced cognitive impairment.

Early Life Irradiation-Induced Hypoplasia and Impairment of Neurogenesis in the Dentate Gyrus and Adult Depression Are Mediated by MicroRNA- 34a-5p/T-Cell Intracytoplasmic Antigen-1 Pathway

Early life radiation exposure causes abnormal brain development, leading to adult depression. However, few studies have been conducted to explore pre- or post-natal irradiation-induced depression-related neuropathological changes. Relevant molecular mechanisms are also poorly understood. We induced adult depression by irradiation of mice at postnatal day 3 (P3) to reveal hippocampal neuropathological changes and investigate their molecular mechanism, focusing on MicroRNA (miR) and its target mRNA and protein. P3 mice were irradiated by γ-rays with 5Gy, and euthanized at 1, 7 and 120 days after irradiation. A behavioral test was conducted before the animals were euthanized at 120 days after irradiation. The animal brains were used for different studies including immunohistochemistry, CAP-miRSeq, Real-Time Quantitative Reverse Transcription PCR (qRT-PCR) and western blotting. The interaction of miR-34a-5p and its target T-cell intracytoplasmic antigen-1 (Tia1) was confirmed by luciferase reporter assay. Overexpression of Tia1 in a neural stem cell (NSC) model was used to further validate findings from the mouse model. Irradiation with 5 Gy at P3 induced depression in adult mice. Animal hippocampal pathological changes included hypoplasia of the infrapyramidal blade of the stratum granulosum, aberrant and impaired cell division, and neurogenesis in the dentate gyrus. At the molecular level, upregulation of miR-34a-5p and downregulation of Tia1 mRNA were observed in both animal and neural stem cell models. The luciferase reporter assay and gene transfection studies further confirmed a direct interaction between miR-43a-5p and Tia1. Our results indicate that the early life γ-radiation-activated miR-43a-5p/Tia1 pathway is involved in the pathogenesis of adult depression. This novel finding may provide a new therapeutic target by inhibiting the miR-43a-5p/Tia1 pathway to prevent radiation-induced pathogenesis of depression.

Exploring Hyperoxia Effects in Cancer-From Perioperative Clinical Data to Potential Molecular Mechanisms

Increased inspiratory oxygen concentration is constantly used during the perioperative period of cancer patients to prevent the potential development of hypoxemia and to provide an adequate oxygen transport to the organs, tissues and cells. Although the primary tumours are surgically removed, the effects of perioperative hyperoxia exposure on distal micro-metastases and on circulating cancer cells can potentially play a role in cancer progression or recurrence. In clinical trials, hyperoxia seems to increase the rate of postoperative complications and, by delaying postoperative recovery, it can alter the return to intended oncological treatment. The effects of supplemental oxygen on the long-term mortality of surgical cancer patients offer, at this point, conflicting results. In experimental studies, hyperoxia effects on cancer biology were explored following multiple pathways. In cancer cell cultures and animal models, hyperoxia increases the production of reactive oxygen species (ROS) and increases the oxidative stress. These can be followed by the induction of the expression of Brain-derived neurotrophic factor (BDNF) and other molecules involved in angiogenesis and by the promotion of various degrees of epithelial mesenchymal transition (EMT).

Analysis of the Applicability of microRNAs in Peripheral Blood Leukocytes as Biomarkers of Sensitivity and Exposure to Fractionated Radiotherapy towards Breast Cancer

Biomarkers for predicting individual response to radiation and for dose verification are needed to improve radiotherapy. A biomarker should optimally show signal fidelity, meaning that its level is stable and proportional to the absorbed dose. miRNA levels in human blood serum were suggested as promising biomarkers. The aim of the present investigation was to test the miRNA biomarker in leukocytes of breast cancer patients undergoing external beam radiotherapy. Leukocytes were isolated from blood samples collected prior to exposure (control); on the day when a total dose of 2 Gy, 10 Gy, or 20 Gy was reached; and one month after therapy ended (46-50 Gy in total). RNA sequencing was performed and univariate analysis was used to analyse the effect of the radiation dose on the expression of single miRNAs. To check if combinations of miRNAs can predict absorbed dose, a multinomial logistic regression model was built using a training set from eight patients (representing 40 samples) and a validation set with samples from the remaining eight patients (15 samples). Finally, Broadside, an explorative interaction mining tool, was used to extract sets of interacting miRNAs. The most prominently increased miRNA was miR-744-5p, followed by miR-4461, miR-34a-5p, miR-6513-5p, miR-1246, and miR-454-3p. Decreased miRNAs were miR-3065-3p, miR-103a-2-5p, miR-30b-3p, and miR-5690. Generally, most miRNAs showed a relatively strong inter-individual variability and different temporal patterns over the course of radiotherapy. In conclusion, miR-744-5p shows promise as a stable miRNA marker, but most tested miRNAs displayed individual signal variability which, at least in this setting, may exclude them as sensitive biomarkers of radiation response.

Extracellular vesicle-derived miRNA as a novel regulatory system for bi-directional communication in gut-brain-microbiota axis

The gut-brain-microbiota axis (GBMAx) coordinates bidirectional communication between the gut and brain, and is increasingly recognized as playing a central role in physiology and disease. MicroRNAs are important intracellular components secreted by extracellular vesicles (EVs), which act as vital mediators of intercellular and interspecies communication. This review will present current advances in EV-derived microRNAs and their potential functional link with GBMAx. We propose that EV-derived microRNAs comprise a novel regulatory system for GBMAx, and a potential novel therapeutic target for modifying GBMAx in clinical therapy.

MicroRNA: a novel implication for damage and protection against ionizing radiation

Ionizing radiation (IR) is a form of high energy. It poses a serious threat to organisms, but radiotherapy is a key therapeutic strategy for various cancers. It is significant to reduce radiation injury but maximize the effect of radiotherapy. MicroRNAs (miRNAs) are posttranscriptionally regulatory factors involved in cellular radioresponse. In this review, we show how miRNAs regulate important genes on cellular response to IR-induced damage and how miRNAs participate in IR-induced carcinogenesis. Additionally, we summarize the experimental and clinical evidence for miRNA involvement in radiotherapy and discuss their potential for improvement of radiotherapy. Finally, we highlight the role that miRNAs play in accident exposure to IR or radiotherapy as predictive biomarker. miRNA therapeutics have shown great perspective in radiobiology; miRNA may become a novel strategy for damage and protection against IR.

Neuronal Development-Related miRNAs as Biomarkers for Alzheimer's Disease, Depression, Schizophrenia and Ionizing Radiation Exposure

Radiation exposure may induce Alzheimer's disease (AD), depression or schizophrenia. A number of experimental and clinical studies suggest the involvement of miRNA in the development of these diseases, and also in the neuropathological changes after brain radiation exposure. The current literature review indicated the involvement of 65 miRNAs in neuronal development in the brain. In the brain tissue, blood, or cerebral spinal fluid (CSF), 11, 55, or 28 miRNAs are involved in the development of AD respectively, 89, 50, 19 miRNAs in depression, and 102, 35, 8 miRNAs in schizophrenia. We compared miRNAs regulating neuronal development to those involved in the genesis of AD, depression and schizophrenia and also those driving radiation-induced brain neuropathological changes by reviewing the available data. We found that 3, 11, or 8 neuronal developmentrelated miRNAs from the brain tissue, 13, 16 or 14 miRNAs from the blood of patient with AD, depression and schizophrenia respectively were also involved in radiation-induced brain pathological changes, suggesting a possibly specific involvement of these miRNAs in radiation-induced development of AD, depression and schizophrenia respectively. On the other hand, we noted that radiationinduced changes of two miRNAs, i.e., miR-132, miR-29 in the brain tissue, three miRNAs, i.e., miR- 29c-5p, miR-106b-5p, miR-34a-5p in the blood were also involved in the development of AD, depression and schizophrenia, thereby suggesting that these miRNAs may be involved in the common brain neuropathological changes, such as impairment of neurogenesis and reduced learning memory ability observed in these three diseases and also after radiation exposure.

Epigenetic Regulation of the Hippocampus, with Special Reference to Radiation Exposure

The hippocampus is crucial in learning, memory and emotion processing, and is involved in the development of different neurological and neuropsychological disorders. Several epigenetic factors, including DNA methylation, histone modifications and non-coding RNAs, have been shown to regulate the development and function of the hippocampus, and the alteration of epigenetic regulation may play important roles in the development of neurocognitive and neurodegenerative diseases. This review summarizes the epigenetic modifications of various cell types and processes within the hippocampus and their resulting effects on cognition, memory and overall hippocampal function. In addition, the effects of exposure to radiation that may induce a myriad of epigenetic changes in the hippocampus are reviewed. By assessing and evaluating the current literature, we hope to prompt a more thorough understanding of the molecular mechanisms that underlie radiation-induced epigenetic changes, an area which can be further explored.

Psychological, educational, and social late effects in adolescent survivors of Wilms tumor: A report from the Childhood Cancer Survivor Study

OBJECTIVE

To delineate the impact of treatment exposures and chronic health conditions on psychological, educational, and social outcomes in adolescent survivors of Wilms tumor.

METHODS

Parent reports from the Childhood Cancer Survivor Study were analyzed for 666 adolescent survivors of Wilms tumor and 698 adolescent siblings. Adjusting for race and household income, survivors were compared to siblings on the Behavior Problems Index and educational outcomes. Multivariable modified Poisson regression estimated relative risks (RR) for therapeutic exposures and chronic health conditions (CTCAE 4.03 graded) among survivors, adjusting for sex, race, income, and age at diagnosis.

RESULTS

Compared to siblings, adolescent survivors of Wilms tumor were more likely to take psychoactive medication (9.4% vs. 5.1%, p < 0.001) and utilize special education services (25.5% vs. 12.6%, p < 0.001) but did not differ significantly in emotional and behavioral problems. Survivors were less likely to be friendless (7.2% vs. 10.1%, p = 0.04) but were more likely to have difficulty getting along with friends (14.5% vs. 7.8%, p < 0.001). Among survivors, use of special education services was associated with abdomen plus chest radiation (RR = 1.98, CI:1.18-3.34). Those with grade 2-4 cardiovascular conditions had higher risk for anxiety/depression (RR = 1.95, CI:1.19-3.19), headstrong behaviors (RR = 1.91, CI:1.26-2.89), and inattention (RR = 1.56, CI:1.02-2.40).

CONCLUSIONS

Adolescent survivors of Wilms tumor were similar to siblings with respect to mental health concerns overall but were more likely to require special education. Monitoring of psychosocial and academic problems through adolescence is warranted, especially among those treated with radiation to the abdomen plus chest or with cardiac conditions.

The roles of the gut microbiota-miRNA interaction in the host pathophysiology

The gut microbiota regulates the biological processes of organisms acting like ‘another’ genome, affecting the health and disease of the host. MicroRNAs, as important physiological regulators, have been found to be involved in health and disease. Recently, the gut microbiota has been reported to affect host health by regulating host miRNAs. For example, Fusobacterium nucleatum could aggravate chemoresistance of colorectal cancer by decreasing the expression of miR-18a* and miR-4802. What’s more, miRNAs can shape the gut microbiota composition, ultimately affecting the host's physiology and disease. miR-515-5p and miR-1226-5p could promote the growth of Fusobacterium nucleatum (Fn) and Escherichia coli (E.coli), which have been reported to drive colorectal cancer. Here, we will review current findings of the interactions between the gut microbiota and microRNAs and discuss how the gut microbiota–microRNA interactions affect host pathophysiology including intestinal, neurological, cardiovascular, and immune health and diseases.

Predictive value and changes of miR-34a after concurrent chemoradiotherapy and its association with cognitive function in patients with nasopharyngeal carcinoma

This study explored the changes and predictive value of miR-34a in nasopharyngeal carcinoma (NPC) after concurrent chemoradiotherapy (CCRT), and its association with cognitive function. Fifty NPC patients admitted to Shunde Hospital, and another fifty healthy individuals were assigned into treated group and control group, respectively. Patients in the treated group received 3 courses of CCRT. The relative expression of miR-34a in the two groups was detected, and the cognitive function of patients was assessed. Diagnostic and predictive values of miR-34a in advanced NPC were analyzed. The expression of miR-34a in the control group was significantly higher than that in the treated group (t=13.364, P<0.001), with an area under the curve (AUC) of 0.979. The expression of miR-34a was significantly upregulated after treatment (t=4.559, P<0.001). After treatment, there were 32 complete remission (CR) patients and 18 partial remission (PR) patients. According to efficacy, CR patients were classified as significant group and PR patients as general group. The expression of miR-34a in the significant group was higher than that in the general group before treatment (t=4.704, P<0.001), with an AUC of 0.852. The Montreal Cognitive Assessment (MoCA) score was significantly decreased after treatment (t=13.042, P<0.001). The expression of miR-34a was positively correlated with the MoCA score after treatment, that is, MoCA score gradually increased with the upregulation of miR-34a expression (r=0.379, P=0.006). There is a positive correlation between miR-34a and cognitive function of patients. Moreover, the expression of miR-34a can be used as a potential predictor of the efficacy of CCRT in patients with NPC.

miR-34a induces spine damages via inhibiting synaptotagmin-1 in depression

MicroRNAs (miRNAs) are noncoding RNAs that participate in the pathophysiology of depression by targeting many functional genes. As shown in our previous study, chronic stress up-regulates miR-34a in the hippocampus. However, little is known about the mechanism by which miR-34a regulates the process of depression or its functions as an antidepressant by regulating its targets. In the present study, the dynamic alterations in miR-34a expression and the mechanism underlying miR-34a regulation were assessed after the administration of the antidepressant fluoxetine to mice exposed to chronic stress. In addition, the effects of miR-34a inhibition on mice were directly evaluated. Both lipopolysaccharide (LPS) and corticosterone treatment caused depression-like symptoms and increased miR-34a expression. Additionally, the expression of miR-34a, which was regulated by tropomyosin receptor kinase B (TrkB)/MEK1/ERK signaling, was consistent with the onset of action of fluoxetine. A luciferase reporter assay identified synaptotagmin-1 and Bcl-2 as the targets of miR-34a. Moreover, a miR-34a antagomir exerted antidepressant-like effects, activated TrkB/MEK1/ERK signaling and improved spine morphology in the hippocampus. In conclusion, hippocampal miR-34a overexpression was a typical feature in depression-like animals, and miR-34a downregulation exerts antidepressant-like effects by restoring the spine morphology through its target synaptotagmin-1.

•

LPS and corticosterone cause depression and miR-34a overexpression.

•

Fluoxetine affects miR-34a in a dynamic alteration in chronic stress.

•

Inhibition of TrkB and ERK signaling upregulates the expression of miR-34a.

•

Synaptotagmin-1 and Bcl-2 are the targets of miR-34a.

•

Inhibition of miR-34a improves spinal morphology.

Gut Microbiota Metabolite Fights Against Dietary Polysorbate 80-Aggravated Radiation Enteritis

Radiation therapy is a cornerstone of modern management methods for malignancies but is accompanied by diverse side effects. In the present study, we showed that food additives such as polysorbate 80 (P80) exacerbate irradiation-induced gastrointestinal (GI) tract toxicity. A 16S ribosomal RNA high-throughput sequencing analysis indicated that P80 consumption altered the abundance and composition of the gut microbiota, leading to severe radiation-induced GI tract injury. Mice harboring fecal microbes from P80-treated mice were highly susceptible to irradiation, and antibiotics-challenged mice also represented more sensitive to radiation following P80 treatment. Importantly, butyrate, a major metabolite of enteric microbial fermentation of dietary fibers, exhibited beneficial effects against P80 consumption-aggravated intestinal toxicity via the activation of G-protein-coupled receptors (GPCRs) and maintenance of the intestinal bacterial composition in irradiated animals. Moreover, butyrate had broad therapeutic effects on common radiation-induced injury. Collectively, our findings demonstrate that P80 are potential risk factors for cancer patients during radiotherapy and indicate that butyrate might be employed as a therapeutic option to mitigate the complications associated with radiotherapy.

Interactions between the MicroRNAs and Microbiota in Cancer Development: Roles and Therapeutic Opportunities

The human microbiota is made up of the fungi, bacteria, protozoa and viruses cohabiting within the human body. An altered microbiota can provoke diseases such as cancer. The mechanisms by which a modified microbiota can intervene in the onset and progression of neoplastic diseases are manifold. For instance, these include the effects on the immune system and the onset of obesity. A different mechanism seems to be constituted by the continuous and bidirectional relationships existing between microbiota and miRNAs. MiRNAs emerged as a novel group of small endogenous non-coding RNAs from that control gene expression. Several works seem to confirm the presence of a close connection between microbiota and miRNAs. Although the main literature data concern the correlations between microbiota, miRNAs and colon cancer, several researches have revealed the presence of connections with other types of tumour, including the ovarian tumour, cervical carcinoma, hepatic carcinoma, neoplastic pathologies of the central nervous system and the possible implication of the microbiota-miRNAs system on the response to the treatment of neoplastic pathologies. In this review, we summarise the physiological and pathological functions of the microbiota on cancer onset by governing miRNA production. A better knowledge of the bidirectional relationships existing between microbiota and miRNAs could provide new markers for the diagnosis, staging and monitoring of cancer and seems to be a promising approach for antagomir-guided approaches as therapeutic agents.

Circulating microRNAs as Biomarkers of Radiation Exposure: A Systematic Review and Meta-Analysis

PURPOSE

MicroRNAs (miRNAs) were hypothesized to be robust and easily measured biomarkers of radiation exposure, which has led to multiple studies in various clinical and experimental scenarios. We sought to identify evolutionary conserved, radiation-induced circulating miRNAs through a multispecies, integrative systematic review and meta-analysis of miRNAs in radiation.

METHODS AND MATERIALS

The systematic review was registered in the PROSPERO database (ID: 81701). We downloaded a list of studies with the query: (circulating OR plasma OR serum) AND (miRNA or microRNA) AND (radiat* OR radiotherapy OR irradiati*) from MEDLINE (103 studies), EMBASE (364 studies), and Cochrane Database of Systematic Reviews (0 studies). After deleting 116 duplicates, the remaining 351 abstracts were reviewed. Inclusion criteria were experimental study; human, mice, rat or nonhuman primate study; and serum or plasma miRNA expression measured before and after radiation exposure.

RESULTS

The screening procedure yielded 62 research studies. After verification, 30 articles contained data on miRNA expression change after irradiation. Thus, we obtained a database of 131 miRNAs from 96 pairwise post-/preirradiation comparisons reporting 2508 fold changes (FCs) of circulating miRNAs. The meta-analysis showed 28 miRNAs with significant radiation-induced change of their expression in the serum. In metaregression analysis, 7 miRNAs-miR-150 (FC = 0.40; 95% confidence interval [CI], 0.35-0.45), miR-29a (FC = 0.87; 95% CI, 0.79-0.96), miR-29b (FC = 0.85; 95% CI, 0.76-0.96), miR-30c (FC = 1.19; 95% CI, 1.09-1.30), miR-200b (FC = 1.34; 95% CI, 1.21-1.48), miR-320a (FC = 1.13; 95% CI, 1.05-1.23), and miR-30a (FC = 1.18; 95% CI, 1.07-1.30)-significantly correlated with either total or fraction dose of radiation. Additionally, miR-150, miR-320a, miR-200b, and miR-30c correlated significantly with time elapsed since irradiation.

CONCLUSIONS

Circulating miRNAs reflect the impact of ionizing radiation irrespective of the studied species, often in a dose-dependent manner. This makes circulating miRNAs promising biomarkers of radiation exposure.

Cranial irradiation in juvenile mice leads to early and sustained defects in the stem and progenitor cell pools and late cognitive impairments

Cranial irradiation is used in combination with other therapies as a treatment for brain tumours and is thought to contribute to long-term cognitive deficits. Several rodent models have demonstrated that these cognitive deficits may be correlated with damage to neural progenitor cells in the subventricular zone (SVZ) and dentate gyrus (DG), the two neurogenic niches of the brain. Studies in rodent models typically assess the proliferating progenitor population, but rarely investigate the effect of cranial irradiation on the neural stem cell pool. Further, few studies evaluate the effects in juveniles, an age when children typically receive this treatment. Herein, we examine the cellular and behavioural effects of juvenile cranial irradiation on stem and progenitor populations in the two neurogenic regions of the brain and assess cognitive outcomes. We found regionally distinct effects of cranial irradiation in the juvenile brain. In the SVZ, we observed a defect in the stem cell pool and a concomitant decrease in proliferating cells that were maintained for at least one week. In the DG, a similar defect in the stem cell pool and proliferating cells was observed and persisted in the stem cell population. Finally, we demonstrated that cranial irradiation resulted in late cognitive deficits. This study demonstrates that juvenile cranial irradiation leads to regionally distinct defects in the stem and progenitor populations, and late cognitive deficits, which may be important factors in determining therapeutic targets and timing of interventions following cranial irradiation.

Sexual Dimorphism of Gut Microbiota Dictates Therapeutics Efficacy of Radiation Injuries

Accidental or iatrogenic ionizing radiation exposure precipitates acute and chronic radiation injuries. The traditional paradigm of mitigating radiotherapy-associated adverse side effects has ignored the gender-specific dimorphism of patients' divergent responses. Here, the effects of sexual dimorphism on curative efficiencies of therapeutic agents is examined in murine models of irradiation injury. Oral gavage of simvastatin ameliorates radiation-induced hematopoietic injury and gastrointestinal tract dysfunction in male mice, but adversely deteriorates these radiation syndromes in female animals. In a sharp contrast, feeding animals with high-fat diet (HFD) elicites explicitly contrary results. High-throughput sequencing of microbial 16S rRNA, host miRNA, and mRNA shows that simvastatin or HFD administration preventes radiation-altered enteric bacterial taxonomic structure, preserves miRNA expression profile, and reprogrammes the spectrum of mRNA expression in small intestines of male or female mice, respectively. Notably, faecal microbiota transplantation of gut microbes from opposite sexual donors abrogates the curative effects of simvastatin or HFD in respective genders of animals. Together, these findings demonstrate that curative efficiencies of therapeutic strategies mitigating radiation toxicity might be dependent on the gender of patients, thus simvastatin or HFD might be specifically useful for fighting against radiation toxicity in a sex-dependent fashion partly based on sex-distinct gut microbiota composition in preclinical settings.

Dietary Modulation of Intestinal Microbiota: Future Opportunities in Experimental Autoimmune Encephalomyelitis and Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease that affects the functioning of the central nervous system (CNS). Recent studies on MS and its animal model, experimental autoimmune encephalomyelitis (EAE), have shown that the composition and abundance of microbes in the intestinal microbiota are an environmental risk factor for the development of MS and EAE. Changes in certain microbial populations in the gastrointestinal tract can cause MS in humans, but MS inflammation can be reduced or even prevented by introducing other commensal microbes that produce beneficial metabolites. Other risk factors for MS include the presence of an altered gut physiology and the interaction between the intestinal microbiota and the immune system. Metabolites including short-chain fatty acids (SCFAs), such as butyrate, are the primary signaling molecules produced by the intestinal microbiota that interact with the host immune system, suggesting an association between MS pathophysiology and gut microbiota. In addition, several host microRNAs present in the gut have been found to interact with the intestinal microbial community, these interactions may indirectly affect the neurological system. Increasing evidence has shown that regulation of the intestinal microbiota is an important approach for reducing MS inflammation. Thus, here we review the use of diet to alter the gut microbiota and its application in the treatment and prevention of MS.

The intestinal microbiome and its relevance for functionality in older persons

PURPOSE OF REVIEW

This article summarizes the advances of research on the role of the intestinal microbiota in influencing sarcopenia, frailty, and cognitive dysfunction in older individuals, and thus its relevance for healthy active ageing.

RECENT FINDINGS

Age-related alterations of intestinal microbiota composition may negatively influence muscle protein synthesis and function by promoting chronic systemic inflammation, insulin resistance, oxidative stress, and reducing nutrient bioavailability. However, this 'gut-muscle axis' hypothesis is not supported by human data to date. Some observational studies have instead demonstrated that, in older individuals, frailty and Alzheimer-type dementia are associated with fecal microbiota dysbiosis, that is, reduced biodiversity and overexpression of pathobionts. The main possible mechanisms of the 'gut-brain axis' in cognitive function modulation include effects on neurotransmission, neuroinflammation, and amyloid deposition. Conversely, longevity in good health may be associated with the maintenance of a fecal microbiota composition similar to that of healthy young adults. However, the role of gut microbiota as an independent modulator of frailty and cognition still remains uncertain, being influenced by several physiological factors, including diet and exercise.

SUMMARY

The intestinal microbiome composition represents a possible determinant of functional performance in older people, and a promising target for antiaging therapeutic interventions.

Gut microbiota, cognitive frailty and dementia in older individuals: a systematic review

Cognitive frailty, defined as the coexistence of mild cognitive impairment symptoms and physical frailty phenotype in older persons, is increasingly considered the main geriatric condition predisposing to dementia. Recent studies have demonstrated that gut microbiota may be involved in frailty physiopathology by promoting chronic inflammation and anabolic resistance. The contribution of gut microbiota to the development of cognitive impairment and dementia is less defined, even though the concept of "gut-brain axis" has been well demonstrated for other neuropsychiatric disorders. The aim of this systematic review was to summarize the current state-of-the-art literature on the gut microbiota alterations associated with cognitive frailty, mild cognitive impairment and dementia and elucidate the effects of pre- or probiotic administration on cognitive symptom modulation in animal models of aging and human beings. We identified 47 papers with original data (31 from animal studies and 16 from human studies) suitable for inclusion according to our aims. We concluded that several observational and intervention studies performed in animal models of dementia (mainly Alzheimer's disease) support the concept of a gut-brain regulation of cognitive symptoms. Modulation of vagal activity and bacterial synthesis of substances active on host neural metabolism, inflammation and amyloid deposition are the main mechanisms involved in this physiopathologic link. Conversely, there is a substantial lack of human data, both from observational and intervention studies, preventing to formulate any clinical recommendation on this topic. Gut microbiota modulation of cognitive function represents, however, a promising area of research for identifying novel preventive and treatment strategies against dementia.

Origination, change, and modulation of geriatric disease-related gut microbiota during life

The age-related changes in the diversity and composition of the gut microbiota are well described in recent studies. These changes have been suggested to be influenced by age-associated weakening of the immune system and low-grade chronic inflammation, resulting in numerous age-associated pathological conditions. Gut microbiota homeostasis is important throughout the life of the host by providing vital functions to regulate various immunological functions and homeostasis. Based on published results, we summarize the relationship between the gut microbiota and aging-related diseases, especially Parkinson's disease, immunosenescence, rheumatoid arthritis, bone loss, and metabolic syndrome. The change in composition of the gut microbiota and gut ecosystem during life and its influence on the host immunologic and metabolic phenotype are also analyzed to determine factors that affect aging-related diseases. Approaches to maintain host health and prevent or cure geriatric diseases are also discussed.

Circular RNA expression profiles in hippocampus from mice with perinatal glyphosate exposure

Glyphosate is the active ingredient in numerous herbicide formulations. The roles of glyphosate in embryo-toxicity and neurotoxicity have been reported in human and animal models. Recently, several studies have reported evidence linking neurodevelopmental disorders (NDDs) with gestational glyphosate exposure. However, the role of glyphosate in neuronal development is still not fully understood. Our previous study found that perinatal glyphosate exposure resulted in differential microRNA expression in the prefrontal cortex of mouse offspring. However, the mechanism of glyphosate-induced neurotoxicity in the developing brain is still not fully understood. Considering the pivotal role of Circular RNAs (circRNAs) in the regulation of gene expression, a circRNA microarray method was used in this study to investigate circRNA expression changes in the hippocampus of mice with perinatal glyphosate exposure. The circRNA microarrays revealed that 663 circRNAs were significantly altered in the perinatal glyphosate exposure group compared with the control group. Among them, 330 were significantly upregulated, and the other 333 were downregulated. Furthermore, the relative expression levels of mmu-circRNA-014015, mmu-circRNA-28128 and mmu-circRNA-29837 were verified using quantitative real-time polymerase chain reaction (qRT-PCR). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses demonstrated that stress-associated steroid metabolism pathways, such as aldosterone synthesis and secretion pathways, may be involved in the neurotoxicity of glyphosate. These results showed that circRNAs are aberrantly expressed in the hippocampus of mice with perinatal glyphosate exposure and play potential roles in glyphosate-induced neurotoxicity.

Aerobic exercise relieved vascular cognitive impairment via NF-κB/miR-503/BDNF pathway

OBJECTIVE

To investigate the mechanism of aerobic exercise in the relief of vascular cognitive impairment (VCI).

MATERIALS AND METHODS

Latency of Water Maze test was measured at sham, 2VO, 2VO+EX groups. miR-503 and BDNF mRNA levels were detected by quantitative real-time PCR. Protein levels of NF-κB and BDNF were detected by Western blot. Hippocampal neuron cell apoptosis was detected by flow cytometry. Luciferase reporter assay was conducted to investigate the effect of miR-503 on BDNF.

RESULTS

Latency of Water Maze test in 2VO group was longer than Sham group, while exercise shortened the latency. The expressions of NF-κB and miR-503 in 2VO group were higher than Sham group, while exercise downregulated the expressions. BDNF level in 2VO group were downregulated than Sham group, while exercise upregulated the levels. We also found NF-κB, miR-503 levels were upregulated and BDNF level was downregulated in OGD-treated hippocampal neuron cells. In addition, OGD increased the expression of NF-κB and miR-503, and the expression of miR-503 was downregulated when treated with NF-κB inhibitor (PDTC). Moreover, we confirmed BDNF was a direct target of miR-503. OGD decreased the expression of BDNF, while miR-503 inhibitor reversed this effect. And we proved OGD induced cell apoptosis via NF-κB/miR-503/BDNF. Finally, in rats injected with miR-503 inhibitor, latency of Water Maze test was shortened, miR-503 expression was downregulated, and BDNF level was upregulated. While in rats injected with miR-503 mimic, the results were the opposite.

CONCLUSION

Aerobic exercise relieved VCI via NF-κB/miR-503/BDNF pathway.

Gut microbiota modulates alcohol withdrawal-induced anxiety in mice

Excessive alcohol consumption remains a major public health problem that affects millions of people worldwide. Accumulative experimental evidence has suggested an important involvement of gut microbiota in the modulation of host's immunological and neurological functions. However, it is previously unknown whether enteric microbiota is implicated in the formation of alcohol withdrawal-induced anxiety. Using a murine model of chronic alcoholism and withdrawal, we examined the impact of alcohol consumption on the possible alterations of gut microbiota as well as alcohol withdrawal-induced anxiety and behavior changes. The 16S rRNA sequencing revealed that alcohol consumption did not alter the abundance of bacteria, but markedly changed the composition of gut microbiota. Moreover, the transplantation of enteric microbes from alcohol-fed mice to normal healthy controls remarkably shaped the composition of gut bacteria, and elicited behavioral signs of alcohol withdrawal-induced anxiety. Using quantitative real-time polymerase chain reaction, we further confirmed that the expression of genes implicated in alcohol addiction, BDNF, CRHR1 and OPRM1, was also altered by transplantation of gut microbes from alcohol-exposed donors. Collectively, our findings suggested a possibility that the alterations of gut microbiota composition might contribute to the development of alcohol withdrawal-induced anxiety, and reveal potentially new etiologies for treating alcohol addiction.