Let-7/miR-98 regulate Fas and Fas-mediated apoptosis

Let-7i enhances anti-tumour immunity and suppresses ovarian tumour growth

Cancer immunotherapy has seen significant success in the last decade for cancer management by enhancing endogenous cancer immunity. However, immunotherapies developed thus far have seen limited success in the majority of high-grade serous carcinoma (HGSC) ovarian cancer patients. This is largely due to the highly immunosuppressive tumour microenvironment of HGSC and late-stage identification. Thus, novel treatment interventions are needed to overcome this immunosuppression and complement existing immunotherapies. Here, we have identified through analysis of > 600 human HGSC tumours a critical role for Let-7i in modulating the tumoural immune network. Tumoural expression of Let-7i had high positive correlation with anti-cancer immune signatures in HGSC patients. Confirming this role, enforced Let-7i expression in murine HGSC tumours resulted in a significant decrease in tumour burden with a significant increase in tumour T cell numbers in tumours. In concert with the improved tumoural immunity, Let-7i treatment also significantly increased CD86 expression in antigen presenting cells (APCs) in the draining lymph nodes, indicating enhanced APC activity. Collectively, our findings highlight an important role of Let-7i in anti-tumour immunity and its potential use for inducing an anti-tumour effect in HGSC.

Expression of Circulating let-7e and miR-126 May Predict Clinical Remission in Patients With Crohn's Disease Treated With Anti-TNF-α Biologics

BACKGROUND

The identification of new biomarkers predictive of response to antitumor necrosis factor alpha (anti-TNF-α) monoclonal antibodies remains an unmet medical need in Crohn's disease (CD) because a high percentage of patients show no clinical improvement after treatment or can lose response over time. MicroRNAs (miRNAs) can regulate inflammatory and immunological responses and were found to play a role in CD.

METHODS

Baseline serum samples from 37 CD patients previously treated with infliximab or adalimumab, as per clinical practice, were obtained from the serum library at the Gastroenterology Unit of the University Hospital of Pisa, Italy. Patients were categorized as responders or nonresponders based on the following treatment outcomes: clinical remission at weeks 14 and 54 and endoscopic remission at week 54. The expression levels of a panel of selected miRNAs were analyzed by real-time polymerase chain reaction. Comparisons of miRNA expression between responders and nonresponders and statistical analyses were performed by MedCalc and GraphPad Prism software. Receiver operating characteristic curve analyses were calculated to evaluate the predictive performance of potential biomarkers.

RESULTS

Patients in clinical remission at week 14 had a lower let-7e expression, whereas those in clinical remission at week 54 had lower levels of circulating miR-126 than nonresponders. The receiver operating characteristic curve analysis identified optimal cutoff values with assay sensitivity and specificity of 92.9% and 61.1%, for let-7e, and 62.5% and 83.3%, for miR-126, respectively.

CONCLUSION

These results provide evidence that expression levels of circulating let-7e and miR-126 at baseline may predict clinical remission in CD patients treated with anti-TNF-α biologics.

Let-7 suppresses liver fibrosis by inhibiting hepatocyte apoptosis and TGF-β production

OBJECTIVE

FAS-mediated apoptosis of hepatocytes and aberrant TGF-β signaling are major drivers of liver fibrosis. Decreased miRNA let-7 expression in the livers of patients and animals with fibrosis suggests a mechanistic link of let-7 to hepatic fibrogenesis.

METHODS

Using transient transfection we tested the effects of let-7 overexpression and TET3 siRNA knockdown on FAS and TGF-β1 expression and FAS-mediated apoptosis in human and mouse primary hepatocytes. We assessed the therapeutic activity of let-7 miRNA delivered via adeno-associated viral vectors in mouse models of carbon tetrachloride (CCl4)-induced and bile duct ligation (BDL)-induced liver fibrosis.

RESULTS

Let-7 decreased TGF-β1 production from hepatocytes through a negative feedback loop involving TET3. On the other hand, let-7 post-transcriptionally inhibits FAS expression, thereby suppressing hepatocyte apoptosis. Hepatic-specific delivery of let-7 miRNA mitigated liver fibrosis in both CCl4 and BDL mouse models.

CONCLUSIONS

Let-7 is a crucial node in the signaling networks that govern liver fibrosis progression. Let-7 and/or its derivatives may be used as therapeutic agents for liver fibrosis.

Chronic delta-9-tetrahydrocannabinol (THC) treatment counteracts SIV-induced modulation of proinflammatory microRNA cargo in basal ganglia-derived extracellular vesicles

BACKGROUND

Early invasion of the central nervous system (CNS) by human immunodeficiency virus (HIV) (Gray et al. in Brain Pathol 6:1-15, 1996; An et al. in Ann Neurol 40:611-6172, 1996), results in neuroinflammation, potentially through extracellular vesicles (EVs) and their micro RNAs (miRNA) cargoes (Sharma et al. in FASEB J 32:5174-5185, 2018; Hu et al. in Cell Death Dis 3:e381, 2012). Although the basal ganglia (BG) is a major target and reservoir of HIV in the CNS (Chaganti et al. in Aids 33:1843-1852, 2019; Mintzopoulos et al. in Magn Reson Med 81:2896-2904, 2019), whether BG produces EVs and the effect of HIV and/or the phytocannabinoid-delta-9-tetrahydrocannabinol (THC) on BG-EVs and HIV neuropathogenesis remain unknown.

METHODS

We used the simian immunodeficiency virus (SIV) model of HIV and THC treatment in rhesus macaques (Molina et al. in AIDS Res Hum Retroviruses 27:585-592, 2011) to demonstrate for the first time that BG contains EVs (BG-EVs), and that BG-EVs cargo and function are modulated by SIV and THC. We also used primary astrocytes from the brains of wild type (WT) and CX3CR1+/GFP mice to investigate the significance of BG-EVs in CNS cells.

RESULTS

Significant changes in BG-EV-associated miRNA specific to SIV infection and THC treatment were observed. BG-EVs from SIV-infected rhesus macaques (SIV EVs) contained 11 significantly downregulated miRNAs. Remarkably, intervention with THC led to significant upregulation of 37 miRNAs in BG-EVs (SIV-THC EVs). Most of these miRNAs are predicted to regulate pathways related to inflammation/immune regulation, TLR signaling, Neurotrophin TRK receptor signaling, and cell death/response. BG-EVs activated WT and CX3CR1+/GFP astrocytes and altered the expression of CD40, TNFα, MMP-2, and MMP-2 gene products in primary mouse astrocytes in an EV and CX3CR1 dependent manners.

CONCLUSIONS

Our findings reveal a role for BG-EVs as a vehicle with potential to disseminate HIV- and THC-induced changes within the CNS.

Let-7a mimic transfection reduces chemotherapy-induced damage in a mouse ovarian transplantation model

Pharmacological approaches offer a non-invasive and promising option for fertility preservation in young female cancer patients undergoing gonadotoxic therapy. The GnRH-agonists are the only clinically available drugs in this indication, but their use and mechanisms of protection are still controversial. Recently, we have investigated new targeted drugs based on microRNA (miRNA) replacement therapy, and have identified the let-7a miRNA as candidate for fertility preservation strategies. Here, the effect of let-7a replacement during chemotherapy exposure on follicular growth and oocyte maturation capacity was investigated using a mouse ovarian-kidney transplantation model. Newborn mouse ovaries were cultured under different conditions; control, chemotherapy exposure (4-hydroperoxycyclophosphamide, 4-HC), and co-treatment with 4-HC and let-7a mimic transfection (4-HC + let-7a). The ovaries were then transplanted under the kidney capsule of recipient mice and follicular growth, survival, and oocyte in vitro maturation were assessed after 3 weeks. The results showed that the follicular pool was highest in the control group but higher in the 4-HC + let-7a group than the 4-HC group. DNA-damage/apoptosis ratios were higher in all 4-HC-exposed groups compared to control but were reduced in the 4-HC + let-7a group. In addition, the post-transplantation oocyte in vitro maturation rate was higher in the 4-HC + let-7a group compared to the 4-HC group, suggesting better oocyte quality. These results provide new information regarding the beneficial effects of let-7a replacement against chemotherapy-induced ovarian damage and open new perspectives for future in vivo applications.

Plasma miRNA Profile of Crohn's Disease and Rheumatoid Arthritis Patients

Crohn's disease (CD) and rheumatoid arthritis (RA) are immune mediated inflammatory diseases. Several studies indicate a role for microRNAs (miRNAs) in the pathogenesis of a variety of autoimmune diseases, including CD and RA. Our study's goal was to investigate circulating miRNAs in CD and RA patients to identify potential new biomarkers for early detection and personalized therapeutic approaches for autoimmune diseases. For this study, subjects with CD (n = 7), RA (n = 8) and healthy controls (n = 7) were recruited, and plasma was collected for miRNA sequencing. Comparison of the expression patterns of miRNAs between CD and healthy patients identified 99 differentially expressed miRNAs. Out of these miRNAs, 4 were down regulated, while 95 were up regulated. Comparison of miRNAs between RA and healthy patients identified 57 differentially expressed miRNAs. Out of those, 12 were down regulated, while 45 were up regulated. For all the miRNAs down regulated in CD and RA patients, 420 GO terms for biological processes were similarly regulated between both groups. Therefore, the identification of new plasma miRNAs allows the emergence of new biomarkers that can assist in the diagnosis and treatment of CD and RA.

MicroRNA-98 ameliorates doxorubicin-induced cardiotoxicity via regulating caspase-8 dependent Fas/RIP3 pathway

Cardiotoxicity is one of the primary limitations in the clinical use of the anticancer drug doxorubicin (DOX). However, the role of microRNAs (miRNAs) in DOX-induced cardiomyocyte death has not yet been covered. To investigate this, we observed a significant increase in miR-98 expression in neonatal rat ventricular myocytes after DOX treatment, and MTT, LIVE/Dead and Viability/Cytotoxicity staining showed that miR-98 mimic inhibited DOX-induced cell death. This was also confirmed by Flow cytometry and Annexin V-FITC/PI staining. Interestingly, the protein expression of caspase-8 was upregulated by miR-98 mimics during this process, whereas Fas and RIP3 were downregulated. In addition, the effect of miR-98 against the expression of Fas and RIP3 were restored by the specific caspase-8 inhibitor Z-IETD-FMK. Thus, we demonstrate that miR-98 protects cardiomyocytes from DOX-induced injury by regulating the caspase-8-dependent Fas/RIP3 pathway. Our findings enhance understanding of the therapeutic role of miRNAs in the treatment of DOX-induced cardiotoxicity.

The role of miRNAs in MDMX-p53 interplay

MicroRNAs (miRNAs) are endogenous noncoding RNAs of 19-24 nucleotides in length and are tightly related to tumorigenesis and progression. Recent studies have demonstrated that the tumor suppressor p53 and its negative controller MDMX are regulated by miRNAs in different ways. Some miRNAs directly target p53 and regulate its expression and function, whereas some miRNAs target MDMX and regulate p53's activity indirectly. The overexpression of several miRNAs can restore the activity of p53 by negatively regulating MDMX in cancer cells. Therefore, a better understanding of the miRNAs-MDMX-p53 network will put forward potential research directions for developing anticancer therapeutics. In the present review, we mainly focus on the regulatory effects of miRNAs on the MDMX-p53 interplay as well as the role of the miRNAs-MDMX-p53 network in human cancer.

The role of RNA-binding and ribosomal proteins as specific RNA translation regulators in cellular differentiation and carcinogenesis

Tight control of mRNA expression is required for cell differentiation; imbalanced regulation may lead to developmental disorders and cancer. The activity of the translational machinery (including ribosomes and translation factors) regulates the rate (slow or fast) of translation of encoded proteins, and the quality of these proteins highly depends on which mRNAs are available for translation. Specific RNA-binding and ribosomal proteins seem to play a key role in controlling gene expression to determine the differentiation fate of the cell. This demonstrates the important role of RNA-binding proteins, specific ribosome-binding proteins and microRNAs as key molecules in controlling the specific proteins required for the differentiation or dedifferentiation of cells. This delicate balance between specific proteins (in terms of quality and availability) and post-translational modifications occurring in the cytoplasm is crucial for cell differentiation, dedifferentiation and oncogenic potential. In this review, we report how defects in the regulation of mRNA translation can be dependent on specific proteins and can induce an imbalance between differentiation and dedifferentiation in cell fate determination.

MicroRNA-98 reduces nerve growth factor expression in nicotine-induced airway remodeling

Evolving evidence suggests that nicotine may contribute to impaired asthma control by stimulating expression of nerve growth factor (NGF), a neurotrophin associated with airway remodeling and airway hyperresponsiveness. We explored the hypothesis that nicotine increases NGF by reducing lung fibroblast (LF) microRNA-98 (miR-98) and PPARγ levels, thus promoting airway remodeling. Levels of NGF, miR-98, PPARγ, fibronectin 1 (FN1), endothelin-1 (EDN1, herein referred to as ET-1), and collagen (COL1A1 and COL3A1) were measured in human LFs isolated from smoking donors, in mouse primary LFs exposed to nicotine (50 μg/ml), and in whole lung homogenates from mice chronically exposed to nicotine (100 μg/ml) in the drinking water. In selected studies, these pathways were manipulated in LFs with miR-98 inhibitor (anti-miR-98), miR-98 overexpression (miR-98 mimic), or the PPARγ agonist rosiglitazone. Compared with unexposed controls, nicotine increased NGF, FN1, ET-1, COL1A1, and COL3A1 expression in human and mouse LFs and mouse lung homogenates. In contrast, nicotine reduced miR-98 levels in LFs in vitro and in lung homogenates in vivo Treatment with anti-miR-98 alone was sufficient to recapitulate increases in NGF, FN1, and ET-1, whereas treatment with a miR-98 mimic significantly suppressed luciferase expression in cells transfected with a luciferase reporter linked to the putative seed sequence in the NGF 3'UTR and also abrogated nicotine-induced increases in NGF, FN1, and ET-1 in LFs. Similarly, rosiglitazone increased miR-98 and reversed nicotine-induced increases in NGF, FN1, and ET-1. Taken together, these findings demonstrate that nicotine-induced increases in NGF and other markers of airway remodeling are negatively regulated by miR-98.

RiPerC Attenuates Cerebral Ischemia Injury through Regulation of miR-98/PIK3IP1/PI3K/AKT Signaling Pathway

Background

Cerebral ischemic stroke is a refractory disease which seriously endangers human health. Remote ischemic perconditioning (RiPerC) by which the sublethal ischemic stimulus is administered during the ischemic event is beneficial after an acute stroke. However, the regulatory mechanism of RiPerC that relieves cerebral ischemic injury is still not completely clear.

Methods

In the present study, we investigated the regulatory mechanism of RiPerC in a rat model of ischemia induced by the middle cerebral artery occlusion (MCAO). Forty-eight adult male Sprague-Dawley (SD) rats were injected intracerebroventricularly with miR-98 agomir, miR-98 antagomir, or their negative controls (agomir-NC, antagomir-NC) 2 h before MCAO or MCAO+RiPerC followed by animal behavior tests and infraction volume measurement at 24 h after MCAO. The expression of miR-98, PIK3IP1, and tight junction proteins in rat hippocampus and cerebral cortex tissues was detected by quantitative polymerase chain reaction (qPCR) and Western blot (WB). Enzyme-linked immunosorbent assay (ELISA) was used to assess the IL-1β, IL-6, and TNF-α levels in the rat serum.

Results

The results showed that in MCAO group, the expression of PIK3IP1 was upregulated, but decreased after RiPerC treatment. Then, we found that PIK3IP1 was a potential target of miR-98. Treatment with miR-98 agomir decreased the infraction volume, reduced brain edema, and improved neurological functions compared to control rats. But treating with miR-98 antagomir in RiPerC group, the protective effect on cerebral ischemia injury was canceled.

Conclusion

Our finding indicated that RiPerC inhibited the MCAO-induced expression of PIK3IP1 through upregulated miR-98, thereby reducing the apoptosis induced by PIK3IP1 through the PI3K/AKT signaling pathway, thus reducing the cerebral ischemia-reperfusion injury.

Ischemia/reperfusion injured intestinal epithelial cells cause cortical neuron death by releasing exosomal microRNAs associated with apoptosis, necroptosis, and pyroptosis

To date, there is no good evidence that intestine epithelial cells (IEC) affected by ischemia/reperfusion (I/R) injury are able to cause cortical neuron injury directly. Additionally, it remains unclear whether the neuronal damage caused by I/R injured IEC can be affected by therapeutic hypothermia (TH, 32 °C). To address these questions, we performed an oxygen–glucose deprivation (OGD) affected IEC-6-primary cortical neuron coculture system under normothermia (37 °C) or TH (32 °C) conditions. It was found that OGD caused hyperpermeability in IEC-6 cell monolayers. OGD-preconditioned IEC-6 cells caused cortical neuronal death (e.g., decreased cell viability), synaptotoxicity, and neuronal apoptosis (evidenced by increased caspase-3 expression and the number of TUNEL-positive cells), necroptosis (evidenced by increased receptor-interacting serine/threonine-protein kinase-1 [RIPK1], RIPK3 and mixed lineage kinase domain-like pseudokinase [MLKL] expression), and pyroptosis (evidenced by an increase in caspase-1, gasdermin D [GSDMD], IL-1β, IL-18, the apoptosis-associated speck-like protein containing a caspase recruitment domain [ASC], and nucleotide oligomerization domain [NOD]-like receptor [NLRP]-1 expression). TH did not affect the intestinal epithelial hyperpermeability but did attenuate OGD-induced neuronal death and synaptotoxicity. We also performed quantitative real-time PCR to quantify the genes encoding 84 exosomal microRNAs in the medium of the control-IEC-6, the control-neuron, the OGD-IEC-6 at 37 °C, the OGD-IEC-6 at 32 °C, the neuron cocultured with OGD-IEC-6 at 37 °C, and the neurons cocultured with OGD-IEC-6 at 32 °C. We found that the control IEC-6 cell s or cortical neurons are able to secrete a basal level of exosomal miRNAs in their medium. OGD significantly up-regulated the basal level of each parameter for IEC-6 cells. As compared to those of the OGD-IEC-6 cells or the control neurons, the OGD-IEC-6 cocultured neurons had significantly higher levels of 19 exosomal miRNAs related to apoptosis, necroptosis, and/or pyroptosis events. Our results identify that I/R injured intestinal epithelium cells can induce cortical neuron death via releasing paracrine mediators such as exosomal miRNAs associated with apoptosis, necroptosis, and/or pyroptosis, which can be counteracted by TH.

Hyperglycemia-related FAS gene and hsa-let-7b-5p as markers of poor outcomes for ischaemic stroke

BACKGROUND AND PURPOSE

Hyperglycemia in acute stroke leads to poor neurological outcomes. The role of microRNA (miRNA) in hyperglycemia-associated genes can provide new avenues for stroke prognostic applications. We aimed to identify novel genes and their regulated miRNAs that are associated with hyperglycemia-induced unfavorable stroke outcomes and further validated in the plasma exosome. Moreover, we intended to evaluate the prognostic ability of miRNA-messenger RNA (mRNA) biomarkers in addition to using traditional risk factors.

METHODS

After the integration analysis of small RNA sequencing and mRNA polymerase chain reaction array, two mRNAs and six miRNAs were selected for validation in middle cerebral artery occlusion animal models and ischaemic stroke patients. Receiver operator characteristic analysis was used to determine the performance of mRNA and miRNA expression.

RESULTS

The increased Fas expression was associated with hyperglycemia after acute stroke onset in animal and human studies. In addition, Fas gene level was significantly higher in patients with an unfavorable outcome when compared with patients with a favorable outcome. The expression of Fas and miRNA hsa-let-7b-5p in addition to traditional risk factors could increase the discrimination and predictive ability for poor prognosis. The higher exosomal Fas was further observed among patients with an unfavorable outcome, suggesting Fas signal transporting through exosome in the circulation system.

CONCLUSIONS

Combined analyses of Fas and has-let-7b-5p expression in addition to traditional risk factors are favorable prognostic biomarkers for predicting poor neurological outcomes at 3 months after stroke onset in ischaemic stroke patients. Additional studies are required to address the precise role of the apoptosis pathway in unfavorable hyperglycemia-induced stroke outcomes.

Circulating miRNAs as Potential Biomarkers in Myasthenia Gravis: Tools for Personalized Medicine

Myasthenia gravis (MG) is an autoimmune disease caused by antibodies which attack receptors at the neuromuscular junction. One of the main difficulties in predicting the clinical course of MG is the heterogeneity of the disease, where disease progression differs greatly depending on the subgroup that the patient is classified into. MG subgroups are classified according to: age of onset [early-onset MG (EOMG; onset ≤ 50 years) versus late-onset MG (LOMG; onset > 50 years]; the presence of a thymoma (thymoma-associated MG); antibody subtype [acetylcholine receptor antibody seropositive (AChR+) and muscle-specific tyrosine kinase antibody seropositive (MuSK+)]; as well as clinical subtypes (ocular versus generalized MG). The diagnostic tests for MG, such as antibody titers, neurophysiological tests, and objective clinical fatigue score, do not necessarily reflect disease progression. Hence, there is a great need for reliable objective biomarkers in MG to follow the disease course as well as the individualized response to therapy toward personalized medicine. In this regard, circulating microRNAs (miRNAs) have emerged as promising potential biomarkers due to their accessibility in body fluids and unique profiles in different diseases, including autoimmune disorders. Several studies on circulating miRNAs in MG subtypes have revealed specific miRNA profiles in patients’ sera. In generalized AChR+ EOMG, miR-150-5p and miR-21-5p are the most elevated miRNAs, with lower levels observed upon treatment with immunosuppression and thymectomy. In AChR+ generalized LOMG, the miR-150-5p, miR-21-5p, and miR-30e-5p levels are elevated and decrease in accordance with the clinical response after immunosuppression. In ocular MG, higher levels of miR-30e-5p discriminate patients who will later generalize from those remaining ocular. In contrast, in MuSK+ MG, the levels of the let-7 miRNA family members are elevated. Studies of circulating miRNA profiles in Lrp4 or agrin antibody-seropositive MG are still lacking. This review summarizes the present knowledge of circulating miRNAs in different subgroups of MG.

MicroRNA let-7g-5p alleviates murine collagen-induced arthritis by inhibiting Th17 cell differentiation

Rheumatoid arthritis (RA) is a chronic and systemic autoimmune disease with complicated pathogenesis. IL-17-producing T helper cells (Th17) are important players in the RA process. Despite numerous researches have proven that microRNAs (miRNAs) are crucial to regulate autoimmune diseases including RA, the effect of miRNAs on Th17 cell differentiation and function in the RA progress is not clear. Here, our results showed that the expression of miRNA let-7g-5p was substantially lower in RA patients and CIA mice compared with healthy controls, accompanied by the increased Th17 cell population. Furthermore, the inhibition of let-7g-5p on Th17 cell differentiation and function were verified in vitro. Notably, the disease severity in CIA mice was significantly alleviated after the treatment of let-7g-5p mimics. In addition, let-7g-5p mimics treatment markedly down-regulated the frequency of Th17 cells in CIA mice. Taken together, our findings indicate that let-7g-5p can ameliorate CIA through blocking the differentiation of Th17 cells, which may be a novel strategy to treat autoimmune diseases such as RA.

Functions and mechanism of noncoding RNA in the somatic cells of the testis

ncRNAs are involved in numerous biological processes by regulating gene expression and cell stability. Studies have shown that ncRNAs also contribute to spermatogenesis. Leydig cells (LCs) and Sertoli cells (SCs) are somatic cells of the testis that support spermatogenesis and are vital to male fertility. In this review, we summarized the findings from studies on ncRNAs in SCs and LCs. In SCs, ncRNAs play key roles in phagocytosis, immunoprotection and development of SCs. In LCs, ncRNAs are involved in steroidogenesis, in particular production of testosterone as well as development of LCs. Here, we discuss the possible target genes and functions of ncRNAs in both types of cells. These ncRNAs regulate the expression of target genes or mRNA coding sequence regions, resulting in a chain reaction that influences cell function. In addition, microRNAs, lncRNAs, piRNA-like RNAs (pilRNAs) and natural antisense transcripts (NATs) are discussed in this review. In summary, we suggest that these ncRNAs might act in coordination to control spermatogenesis and maintain the environmental homeostasis of the testis.

Role of MicroRNAs in Parkinson's Disease

Parkinson's disease (PD) is a disabling neurodegenerative disease that manifests with resting tremor, bradykinesia, rigidity and postural instability. Since the discovery of microRNAs (miRNAs) in 1993, miRNAs have been shown to be important biological molecules involved in diverse processes to maintain normal cellular functions. Over the past decade, many studies have reported dysregulation of miRNA expressions in PD. Here, we identified 15 miRNAs from 34 reported screening studies that demonstrated dysregulation in the brain and/or neuronal models, cerebrospinal fluid (CSF) and blood. Specific miRNAs-of-interest that have been implicated in PD pathogenesis include miR-30, miR-29, let-7, miR-485 and miR-26. However, there are several challenges and limitations in drawing definitive conclusions due to the small sample size in clinical studies, varied laboratory techniques and methodologies and their incomplete penetrance of the blood-brain barrier. Developing an optimal delivery system and unravelling druggable targets of miRNAs in both experimental and human models and clinical validation of the results may pave way for novel therapeutics in PD.

Sheng Mai San protects H9C2 cells against hyperglycemia-induced apoptosis

BACKGROUND

Sheng Mai San (SMS) has been proven to exhibit cardio-protective effects. This study aimed to explore the molecular mechanisms of SMS on hyperglycaemia (HG)-induced apoptosis in H9C2 cells.

METHODS

HG-induced H9C2 cells were established as the experimental model, and then treated with SMS at 25, 50, and 100 μg/mL. H9C2 cell viability and apoptosis were quantified using MTT and Annexin V-FITC assays, respectively. Furthermore, Bcl-2/Bax signalling pathway protein expression and Fas and FasL gene expression levels were quantified using western blotting and RT-PCR, respectively.

RESULTS

SMS treatments at 25, 50, 100 μg/mL significantly improved H9C2 cell viability and inhibited H9C2 cell apoptosis (p < 0.05). Compared to the HG group, SMS treatment at 25, 50, and 100 μg/mL significantly downregulated p53 and Bax expression and upregulated Bcl-2 expression (p < 0.05). Moreover, SMS treatment at 100 μg/mL significantly downregulated Fas and FasL expression level (p < 0.05) when compared to the HG group.

CONCLUSION

SMS protects H9C2 cells from HG-induced apoptosis probably by downregulating p53 expression and upregulating the Bcl-2/Bax ratio. It may also be associated with the inhibition of the Fas/FasL signalling pathway.

Serum miRNAs are potential biomarkers for the detection of disc degeneration, among which miR-26a-5p suppresses Smad1 to regulate disc homeostasis

Disc degeneration is a common clinical condition in which damaged discs cause chronic pain; however, a laboratory diagnosis method for its detection is not available. As circulating miRNAs have potential as biomarkers, their application in disc degeneration has not been explored. Here, we prepared serum miRNAs from a mouse disc degeneration model and performed miRNA‐Seq and quantitative PCR to characterize disc degeneration–associated miRNAs. We identified three miRNAs, including miR‐26a‐5p, miR‐122‐5p and miR‐215‐5p, undergoing perturbation during the pathogenesis of disc degeneration. Specifically, the levels of miR‐26a‐5p in the serum demonstrated steady increases in the model of disc degeneration, compared with those in the pre‐injury samples of younger age or compared with normal controls of the same age but without disc degeneration, whereas the miRNAs miR‐122‐5p and miR‐215‐5p exhibited lower expression in post‐injury samples than in their counterparts without the surgery. Moreover, we found that miR‐26a‐5p targets Smad1 expression, and Smad1 negatively regulates Vegfa expression in disc cells, and thus, miR‐26a‐5p promotes disc degeneration. In summary, we established a method that consistently profiles circulating miRNAs and identified multiple miRNAs as promising biomarkers for disc degeneration, among which miR‐26a‐5p enhances VEGF expression during disc degeneration through targeting Smad1 signalling.

Expression profile of Let-7s in peripheral blood mononuclear cells of normal and severe preeclampsia pregnant women

HEADINGS AIM

We aimed to investigate if the let-7 s expression level in the serum of peripheral blood from pregnant women with severe pre-eclampsia and normal pregnant women is related to the incidence of severe pre-eclampsia.

METHODS

Total RNA was extracted from collected peripheral blood mononuclear cells from 20 or over weeks pregnant women diagnosed with severe pre-eclampsia (age: 31.57 ± 4.94) and normal pregnant women (age: 29.75 ± 4.6) respectively, followed by real-time PCR to examine the expression of let-7 s. Correlation between let-7 s expression level and maternal age or body mass index of the normal pregnant women were also analyzed using SPSS21.0 software.

RESULTS

Let-7a and let-7 g were significantly increased in pregnant women with severe pre-eclampsia by 4.67 fold and 2.37 fold respectively compared to the normal pregnant women, whereas there was no significant difference in let-7b and let-7i. Moreover, there was no correlation between maternal age or body mass index and the expression level of let-7a, let-7b, let-7 g, and let-7i.

CONCLUSIONS

In conclusion, let-7a and let-7 g were significantly increased in the PBMCs of severe pre-eclampsia women compared to normal controls. Moreover, their expression level was not correlated to the maternal age or body mass of patients. Our data indicated that let-7a and let-7 g may be considered as predictive markers for SPE.

Survival of Naïve T Cells Requires the Expression of Let-7 miRNAs

Maintaining the diversity and constant numbers of naïve T cells throughout the organism's lifetime is necessary for efficient immune responses. Naïve T cell homeostasis, which consists of prolonged survival, occasional proliferation and enforcement of quiescence, is tightly regulated by multiple signaling pathways which are in turn controlled by various transcription factors. However, full understanding of the molecular mechanisms underlying the maintenance of the peripheral T cell pool has not been achieved. In the present study, we demonstrate that T cell-specific deficiency in let-7 miRNAs results in peripheral T cell lymphopenia resembling that of Dicer1 knockout mice. Deletion of let-7 leads to profound T cell apoptosis while overexpression prevents it. We further show that in the absence of let-7, T cells cannot sustain optimal levels of the pro-survival factor Bcl2 in spite of the intact IL-7 signaling, and re-expression of Bcl2 in let-7 deficient T cells completely rescues the survival defect. Thus, we have uncovered a novel let-7-dependent mechanism of post-transcriptional regulation of naïve T cell survival in vivo.

Wide Profiling of Circulating MicroRNAs in Spinocerebellar Ataxia Type 7

Spinocerebellar ataxia type 7 (SCA7), a neurodegenerative disease characterized by cerebellar ataxia and retinal degeneration, is caused by a CAG repeat expansion in the ATXN7 gene coding region. Disease onset and progression are highly variable between patients, thus identification of specific/sensitive biomarkers that can improve the monitoring of disease progression is an immediate need. Because altered expression of circulating microRNAs (miRNAs) has been shown in various neurological diseases, they could be useful biomarkers for SCA7. In this study, we showed, to our knowledge for the first time, the expression profile of circulating miRNAs in SCA7. Using the TaqMan profiling low density array (TLDA), we found 71 differentially expressed miRNAs in the plasma of SCA7 patients, compared with healthy controls. The reliability of TLDA data was validated independently by quantitative real-time polymerase chain reaction in an independent cohort of patients and controls. We identified four validated miRNAs that possesses the diagnostic value to discriminate between healthy controls and patients (hsa-let-7a-5p, hsa-let7e-5p, hsa-miR-18a-5p, and hsa-miR-30b-5p). The target genes of these four miRNAs were significantly enriched in cellular processes that are relevant to central nervous system function, including Fas-mediated cell-death, heparansulfate biosynthesis, and soluble-N-ethylmaleimide-sensitive factor activating protein receptor pathways. Finally, we identify a signature of four miRNAs associated with disease severity that discriminate between early onset and adult onset, highlighting their potential utility to surveillance disease progression. In summary, circulating miRNAs might provide accessible biomarkers for disease stage and progression and help to identify novel cellular processes involved in SCA7.

MicroRNA‑98/PTEN/AKT pathway inhibits cell proliferation and malignant progression of hypopharyngeal carcinoma by MTDH

Laryngeal carcinoma is one of the most common tumors concerning otorhinolaryngology head and neck surgery, however, the pathogenesis of laryngeal carcinoma remains unclear. MicroRNAs (miRNAs) have been reported to play vital roles in the pathogenesis of laryngeal carcinoma Herein, the present study was designed to explore the function and mechanism of miRNA-98 in hypopharyngeal carcinoma. In brief, qRT-PCR, MTT assay, western blot analysis, Transwell assay and luciferase reporter assay were performed. Based on the results, miRNA-98 expression was downregulated in patients with hypopharyngeal carcinoma. Downregulation of miRNA-98 promoted cell growth and migration, and decreased the apoptotic rate of hypopharyngeal carcinoma cells. Overexpression of miRNA-98 increased the apoptotic rate, and inhibited cell growth and migration of hypopharyngeal carcinoma cells. Moreover, luciferase reporter assays revealed that MTDH is a direct target of miRNA-98 and overexpression of miRNA-98 induced the protein expression of PTEN and suppressed that of PI3K and p-Akt. si-MTDH attenuated the anticancer effects of miRNA-98 on hypopharyngeal carcinoma via the PTEN/AKT pathway. To the best of our knowledge, the present study confirmed for the first time that miRNA-98 inhibits hypopharyngeal carcinoma cell proliferation and induces apoptosis via the PTEN/AKT pathway by MTDH.

MicroRNA-98-5p ameliorates oxygen-glucose deprivation/reoxygenation (OGD/R)-induced neuronal injury by inhibiting Bach1 and promoting Nrf2/ARE signaling

MicroRNA-98-5p (miR-98-5p) is a stress-related microRNA (miRNA) that plays an important role in regulating cell survival, apoptosis, and oxidative stress in multiple cell types and diseases. However, little is known about the role of miR-98-5p in cerebral ischemia/reperfusion injury. In this study, we investigated the role and mechanism of miR-98-5p in regulating neuronal injury induced by oxygen-glucose deprivation/reoxygenation (OGD/R), an in vitro model of cerebral ischemia/reperfusion injury. We found that miR-98 expression was significantly altered in neurons in response to OGD/R treatment. Functional experiments showed that overexpression of miR-98-5p inhibited OGD/R-induced apoptosis and reactive oxygen species (ROS) production in neurons, whereas inhibition of miR-98-5p showed the opposite effect. Interestingly, bioinformatics analysis predicted that BTB and CNC homology 1 (Bach1) was a potential target gene of miR-98-5p, that was verified by dual-luciferase reporter assay. Moreover, overexpression of miR-98-5p inhibited Bach1 expression while suppression of miR-98-5p promoted Bach1 expression in neurons. Notably, miR-98-5p was shown to regulate the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the activity of the antioxidant response element (ARE). However, overexpression of Bach1 or silencing of Nrf2 significantly abolished the miR-98-5p-mediated neuroprotective effect. Overall, these results demonstrate that miR-98-5p ameliorates OGD/R-induced neuronal injury in vitro through targeting to promote activation of Nrf2/ARE signaling. Our study suggests that miR-98-5p may play a potential role in cerebral ischemia/reperfusion injury and represents a potential therapeutic target for neuroprotection.

MicroRNA let-7c-5p Suppressed Lipopolysaccharide-Induced Dental Pulp Inflammation by Inhibiting Dentin Matrix Protein-1-Mediated Nuclear Factor kappa B (NF-κB) Pathway In Vitro and In Vivo

Background

Let-7c-5p is down-regulated in dental pulp tissues in inflammatory disorders. The microRNA (miR) molecule shows an anti-inflammation potential due to its direct regulation of dentin matrix protein-1 (DMP1), which promotes inflammation changes in dental pulp tissues. In the present study, the effect of let-7c-5p on lipopolysaccharide (LPS)-induced pulpitis was detected and the associated mechanism was explored.

Material/Methods

Dental pulp stem cells (DPSCs) were isolated from rat dental tissues, infected with let-7c-5p lentivirus particles, and subjected to LPS administration to induce inflammation. Then, the effect of let-7c-5p overexpression on LPS-induced impairments on DPSCs were detected and the mechanism was explained by focusing on the DMP1 expression and NF-κB pathway. The role of DMP1 in the anti-inflammation effect of let-7c-5p was assessed by incubating let-7c-5p-expressed DPSCs with DMP1 protein. The results of in vitro assays were verified in LPS-induced rat pulpitis models.

Results

LPS administration increased the production of IL-1β and TNF-α and decreased DPSCs viability by increasing the expression of DMP1 and activating NF-κB pathway. However, the induced expression of let-7c-5p relieved DPSCs from LPS-induced inflammation and suppressed DMP1 as well as NF-κB pathway. The incubation of let-7c-5p-expressed DPSCs with DMP1 protein blocked the effect of let-7c-5p. In in vivo experiments, the injection of let-7c-5p attenuated LPS-induced pulpitis by inhibiting DMP1-mediated NF-κB pathway.

Conclusions

Findings outlined in the current study demonstrated the dental pulp protecting function of let-7c-5p during LPS-induced inflammation, which was exerted by inhibiting the DMP1-mediated NF-κB pathway.

Role of MiR-98 and Its Underlying Mechanisms in Systemic Lupus Erythematosus

Objective.

T-lymphocyte apoptosis plays a critical role in the pathogenesis of systemic lupus erythematosus (SLE). However, the underlying regulatory mechanisms of apoptosis in SLE remain unclear. The aim of this study was to explore the role of miR-98 in SLE and its underlying mechanisms.

Methods.

Western blotting and quantitative reverse transcription PCR (qRT-PCR) were used to analyze miR-98 and Fas expression. Luciferase reporter assays were performed to identify miR-98 targets. To modify miRNA levels, miR-98 mimics and inhibitor were transfected into cells. A lentiviral construct was used to overexpress the level of Fas in SLE CD4+ T cells. Gene and protein expression were determined by qRT-PCR and Western blotting. Apoptosis levels were evaluated by annexin V staining and flow cytometry.

Results.

Compared to those of healthy donors, miR-98 was downregulated in SLE CD4+ T cells, whereas Fas mRNA and protein expression were upregulated. Upregulation of miR-98 by mimic transfection protected Jurkat cells against Fas-mediated apoptosis at both mRNA and protein levels, while miR-98 inhibitor induced the completely opposite effect. Luciferase reporter assays demonstrated that miR-98 directly targeted Fas mRNA. Further, miR-98 inhibitor induced apoptosis in primary healthy CD4+ T cells through the Fas-caspase axis, while upregulation of miR-98 in SLE CD4+ T cells led to the opposite effect.

Conclusion.

The current study revealed that downregulation of miR-98 induces apoptosis by modulating the Fas-mediated apoptotic signaling pathway in SLE CD4+ T cells. These results suggest that miR-98 might serve as a potential target for SLE treatment.

Expression profiles and function analysis of microRNAs in postovulatory aging mouse oocytes

In this study, microRNA (miRNA) profiles in postovulatory aging mouse oocytes were analyzed by microarray screening and RT-qPCR. Hierarchical cluster analysis on the microarray data and KEGG pathway enrichment analysis on the mRNAs targeted by differentially expressed (DE) miRNAs between two adjacent egg-ages suggest that while only a mild alteration in miRNA expression occurred from 13 to 18 h, a great change took place from 18 to 24 h post hCG injection. Theoretical exploration on functions of the predicted target genes suggest that KEGG pathways enriched by 13-18 h DE miRNAs are correlated with early events of oocyte aging while pathways most enriched by 18-24 h or 24-30 h DE miRNAs are correlated with the late symptoms of aged oocytes. Experimental verification on functions of the key proteins predicted by the KEGG analysis and injection of miR-98 mimics or inhibitors further confirmed that miRNAs played stimulatory/inhibitory roles in postovulatory oocyte aging. In conclusion, marked changes in miRNA expression are associated with significant alterations in function and morphology of postovulatory aging oocytes.

The dynamic changes of main cell types in the microenvironment of sciatic nerves following sciatic nerve injury and the influence of let-7 on their distribution

Schwann cells (SCs), fibroblasts and macrophages are the main cells in the peripheral nerve stumps.

Circulating microRNAs as potential biomarkers in myasthenia gravis patients

MicroRNAs (miRNAs) are small noncoding RNA molecules that bind to specific mRNA targets and regulate a wide range of important biological processes within cells. Circulating miRNAs are released into the extracellular space and can be measured in most biofluids, including blood serum and plasma. Recently, circulating miRNAs have emerged as easily accessible markers in various body fluids with different profiles and quantities specific for different human disorders, including autoimmune diseases. In myasthenia gravis (MG), diagnostic tests such as titers of serum autoantibodies specific for either the acetylcholine receptor (AChR⁺ ) or muscle-specific tyrosine kinase (MuSK⁺ ) do not necessarily reflect disease progression, and there is a great need for reliable objective biomarkers to monitor the disease course and therapeutic response. Recent studies in AChR⁺ MG revealed elevated levels of the immuno-miRNAs miR-150-5p and miR-21-5p. Of particular importance, levels of miR-150-5p were lower in immunosuppressed patients and in patients with clinical improvement following thymectomy. In MuSK⁺ MG, another profile of circulating miRNAs was found, including upregulation of the let-7 family of miRNAs. Here, we summarize the potential role of circulating miRNAs as biomarkers in general and in MG, and highlight important considerations for the analysis of circulating miRNA.

MicroRNA-98 negatively regulates myocardial infarction-induced apoptosis by down-regulating Fas and caspase-3

Acute myocardial infarction (MI) is the leading cause of sudden death worldwide. MicroRNAs (miRs) is a novel class of regulators of cardiovascular diseases such as MI. This study aimed to explore the role of miR-98 in MI and its underlying mechanisms. We found that miR-98 was downregulated both in infarcted and ischemic myocardium of MI mice as well as H₂O₂-treated neonatal rat ventricular myocytes (NRVCs). miR-98 overexpression remarkably increased cell viability and inhibited apoptosis of H₂O₂-treated NRVCs. Meanwhile, overexpression of miR-98 reversed H₂O₂-induced Bcl-2 downregulation and Bax elevation and significantly reduced JC-1 monomeric cells. Meanwhile, miR-98 overexpression attenuated the upregulation of Fas and caspase-3 in H₂O₂-treated cardiomyocytes at the mRNA and protein levels. Dual-luciferase reporter assay showed that miR-98 directly targeted to Fas 3'-UTR. Furthermore, MI mice injected with miR-98-agomir had a significant reduction of apoptotic cells, the serum LDH levels, myocardial caspase-3 activity, Fas and caspase-3 expression in heart tissues. Administration of miR-98-agomir also showed decreased infarct size and improved cardiac function. Collectively, miR-98 is downregulated in the MI heart and NRVCs in response to H₂O₂ stress, and miR-98 overexpression protects cardiomyocytes against apoptosis. Anti-apoptotic effects of miR-98 are associated with regulation of Fas/Caspase-3 apoptotic signal pathway.

The functional consequences and prognostic value of dosage sensitivity in ovarian cancer

Copy number alteration (CNA) represents an important class of genetic variations that may contribute to tumorigenesis, tumor growth and metastatic spread. CNA can directly affect the expression of genes within the CNA regions; however, genes within the CNA regions exhibit heterogeneity in gene dosage sensitivity. In this study, a computational framework was built to identify 1170 dosage-sensitive genes (DSGs) and 1215 dosage-resistant genes (DRGs) that were related to ovarian serous cystadenocarcinoma (OV) through the association between CNA and gene expression. To analyze the different functions of the genes within the two groups, the functional annotation results indicated that DRGs were involved in cancer-related processes like immune response, cell death and apoptosis, while DSGs were enriched in essential processes like the cell cycle and the DNA metabolic process. Meanwhile, two three-dimensional regulatory networks for differentially expressed miRNAs, differentially expressed transcription factors (TFs) and DSGs or DRGs were constructed based on feed-forward loops. We identified key regulators (such as miR-16-5p, miR-98-5p, MYB and HOXA5) and cancer prognosis-related network motifs (such as miR-98-5p-HOXA5-TP53 and miR-16-5p-MYB-IGF1R) after the analysis of network topological features. Our results lead us to speculate that these genes and associated regulators may be potential mechanistic biomarkers for tumorigenesis and progression of cancer. Research on the network characteristics and the role of feed-forward loops in OV tumorigenesis and development could lead to feasible suggestions for the prevention and early diagnosis of OV, which will shed light on understanding the functional mechanism of CNA in cancer.

Curcumin Inhibits LIN-28A through the Activation of miRNA-98 in the Lung Cancer Cell Line A549

Metastasis is common in lung cancer and is associated with poor clinical outcomes and increased mortality. Curcumin is a natural anti-cancer agent that inhibits the metastasis of various cancers by modulating the expression of micro (mi) RNAs such as miR-98, which acts as a tumor suppressor. This study investigated the effect of curcumin on miR-98 expression and in vitro cell line growth and invasiveness in lung cancer. Curcumin treatment enhanced the expression of miR-98 and reduced that of the miR-98 target gene LIN28A as well as matrix metalloproteinase (MMP) 2 and MMP9 in vitro and in vivo. MiR-98 overexpression suppressed lung cancer cell migration and invasion by inhibiting LIN28A-induced MMP2 and MMP9 expression. Meanwhile, LIN28A level was downregulated by overexpression of miR-98 mimic. Induction of miR-98 by curcumin treatment suppressed MMP2 and MMP9 by targeting LIN28A. These findings provide insight into the mechanisms by which curcumin suppresses lung cancer cell line growth in vitro and in vivo and invasiveness in vitro.

Chlamydia preserves the mitochondrial network necessary for replication via microRNA-dependent inhibition of fission

Chlamydiae are intracellular pathogens that depend on the host for their survival and development. Chowdhury et al. demonstrate that Chlamydia trachomatis infection can prevent mitochondrial fission in primary cells by reducing DRP1 abundance via miR-30c–dependent inhibition of p53.

Obligate intracellular bacteria such as Chlamydia trachomatis depend on metabolites of the host cell and thus protect their sole replication niche by interfering with the host cells’ stress response. Here, we investigated the involvement of host microRNAs (miRNAs) in maintaining the viability of C. trachomatis–infected primary human cells. We identified miR-30c-5p as a prominently up-regulated miRNA required for the stable down-regulation of p53, a major suppressor of metabolite supply in C. trachomatis–infected cells. Loss of miR-30c-5p led to the up-regulation of Drp1, a mitochondrial fission regulator and a target gene of p53, which, in turn, severely affected chlamydial growth and had a marked effect on the mitochondrial network. Drp1-induced mitochondrial fragmentation prevented replication of C. trachomatis even in p53-deficient cells. Additionally, Chlamydia maintain mitochondrial integrity during reactive oxygen species–induced stress that occurs naturally during infection. We show that C. trachomatis require mitochondrial ATP for normal development and hence postulate that they preserve mitochondrial integrity through a miR-30c-5p–dependent inhibition of Drp1-mediated mitochondrial fission.

Tissue MicroRNA profiles as diagnostic and prognostic biomarkers in patients with resectable pancreatic ductal adenocarcinoma and periampullary cancers

Background

The aim of this study was to validate previously described diagnostic and prognostic microRNA expression profiles in tissue samples from patients with pancreatic cancer and other periampullary cancers.

Methods

Expression of 46 selected microRNAs was studied in formalin-fixed paraffin-embedded tissue from patients with resected pancreatic ductal adenocarcinoma (n = 165), ampullary cancer (n=59), duodenal cancer (n = 6), distal common bile duct cancer (n = 21), and gastric cancer (n = 20); chronic pancreatitis (n = 39); and normal pancreas (n = 35). The microRNAs were analyzed by PCR using the Fluidigm platform.

Results

Twenty-two microRNAs were significantly differently expressed in patients with pancreatic cancer when compared to healthy controls and chronic pancreatitis patients; 17 miRNAs were upregulated (miR-21-5p, −23a-3p, −31-5p, −34c-5p, −93-3p, −135b-3p, −155-5p, −186-5p, −196b-5p, −203, −205-5p, −210, −222-3p, −451, −492, −614, and miR-622) and 5 were downregulated (miR-122-5p, −130b-3p, −216b, −217, and miR-375). MicroRNAs were grouped into diagnostic indices of varying complexity. Ten microRNAs associated with prognosis were identified (let-7 g, miR-29a-5p, −34a-5p, −125a-3p, −146a-5p, −187, −205-5p, −212-3p, −222-5p, and miR-450b-5p). Prognostic indices based on differences in expression of 2 different microRNAs were constructed for pancreatic and ampullary cancer combined and separately (30, 5, and 21 indices).

Conclusion

The study confirms that pancreatic cancer tissue has a microRNA expression profile that is different from that of other periampullary cancers, chronic pancreatitis, and normal pancreas. We identified prognostic microRNAs and microRNA indices that were associated with shorter overall survival in patients with radically resected pancreatic cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s40364-017-0087-6) contains supplementary material, which is available to authorized users.

Functional changes in mRNA expression and alternative pre-mRNA splicing associated with the effects of nutrition on apoptosis and spermatogenesis in the adult testis

Background

The effects of nutrition on testis mass in the sexually mature male have long been known, however, the cellular and molecular processes of the testis response to nutrition was not fully understood.

Methods

We tested whether the defects in spermatogenesis and increases in germ cell apoptosis in the testis that are induced by under-nutrition are associated with changes in mRNA expression and pre-mRNA alternative splicing using groups of 8 male sheep fed for a 10% increase or 10% decrease in body mass over 65 days.

Results

We identified 2,243 mRNAs, including TP53 and Claudin 11, that were differentially expressed in testis from underfed and well-fed sheep (FDR < 0.1), and found that their expression changed in parallel with variations in germ cell numbers, testis size, and spermatogenesis. Furthermore, pairs of 269 mRNAs and 48 miRNAs were identified on the basis of target prediction. The regulatory effect of miRNAs on mRNA expression, in combination with functional analysis, suggests that these miRNAs are involved in abnormal reproductive morphology, apoptosis and male infertility. Nutrition did not affect the total number of alternative splicing events, but affected 206 alternative splicing events. A total of 159 genes, including CREM, SPATA6, and DDX4, were differentially spliced between dietary treatments, with functions related to RNA splicing and spermatogenesis. In addition, three gene modules were positively correlated with spermatogenesis-related phenotypic traits and negatively related to apoptosis-related phenotypic traits. Among these gene modules, seven (CFLAR, PTPRC, F2R, MAP3K1, EPHA7, APP, BCAP31) were also differentially expressed between nutritional treatments, indicating their potential as markers of spermatogenesis or apoptosis.

Conclusions

Our findings on significant changes in mRNAs and pre-mRNA alternative splicing under-nutrition suggest that they may partly explain the disruption of spermatogenesis and the increase germ cell apoptosis. However, more research is required to verify their causal effects in regulating spermatogenesis and germ cell apoptosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-3385-8) contains supplementary material, which is available to authorized users.

Knockdown of MicroRNA Let-7a Improves the Functionality of Bone Marrow-Derived Mesenchymal Stem Cells in Immunotherapy

Bone marrow-derived mesenchymal stem cells (MSCs) have been recently used in clinical treatment of inflammatory diseases. Practical strategies improving the immunosuppressive property of MSCs are urgently needed for MSC immunotherapy. In this study, we aimed to develop a microRNA-based strategy to improve MSC immunotherapy. Bioinformatic analysis revealed that let-7a targeted the 3' UTR of mRNA of Fas and FasL, both of which are essential for MSCs to induce T cell apoptosis. Knockdown of let-7a by specific inhibitor doubled Fas and Fas ligand (FasL) protein levels in MSCs. Because Fas attracts T cell migration and FasL induces T cell apoptosis, knockdown of let-7a significantly promoted MSC-induced T cell migration and apoptosis in vitro and in vivo. Importantly, MSCs knocked down of let-7a were more efficient to reduce the mortality, prevent the weight loss, suppress the inflammation reaction, and alleviate the tissue lesion of experimental colitis and graft-versus-host disease (GVHD) mouse models. In conclusion, knockdown of let-7a significantly improved the therapeutic effect of MSC cytotherapy on inflammatory bowel diseases and GVHD. With high safety and convenience, knockdown of let-7a is a potential strategy to improve MSC therapy for inflammatory diseases in clinic.

Differentially expressed miRNAs in oxygen‑induced retinopathy newborn mouse models

The present study aimed to identify microRNAs (miRNAs) involved in regulating retinal neovascularization and retinopathy of prematurity (ROP). A total of 80 healthy C57BL/6 neonatal mice were randomly divided into the oxygen-induced retinopathy (OIR) group (n=40), in which 7-day-old mice were maintained in 75% oxygen conditions for 5 days, or the control group (n=40). Following collection of retinal tissue, retinal angiography and hematoxylin and eosin (H&E) staining were performed. Total RNA was also extracted from retinal tissue, and miRNA microarrays and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were performed to identify differentially expressed miRNAs in the two groups. Retinal angiography and H&E staining revealed damage to retinas in the OIR group. Compared with the control group, 67 miRNAs were differentially expressed in the OIR group, of which 34 were upregulated and 33 were downregulated. Of these differentially expressed miRNAs, 32 exhibited a fold change ≥2, of which 21 were upregulated and 11 were downregulated. The results of RT-qPCR for miR-130a-3p and miR-5107-5p were in accordance with those of the miRNA microarray. The newly identified miRNAs may be important in the development of ROP, and may provide a basis for future research into the mechanisms of ROP.

MicroRNA-98 regulates osteogenic differentiation of human bone mesenchymal stromal cells by targeting BMP2

To study the effects of microRNA‐98 (miR‐98) on human bone mesenchymal stromal cells (hBMSCs). The patients undergoing hip arthroplasty were selected by inclusion/exclusion criteria for this study. The extracted hBMSCs were detected of osteogenic differentiation by alizarin red S staining, and of cell phenotype by flow cytometry. Bioinformatics, dual luciferase report, western blotting, RT‐PCR and immunoblotting were used in our study. The hBMSCs were divided into miR‐98 mimics, miR‐98 negative control (NC), miR‐98 inhibitors, Mock and miR‐98 inhibitors + siBMP2 groups. Human bone mesenchymal stromal cells were extracted and purified in vitro and had specific cytological morphology, surface markers and abilities of self‐renewal and differentiation. Compared with the NC group and Mock group, the miR‐98 mimics group showed increased miR‐98 level while the miR‐98 inhibitors group decreased miR‐98 level (both P < 0.01). Dual luciferase reporter showed BMP2 was the target gene of miR‐98. The levels of mRNA and protein expression of BMP2, protein expression of RUNX2, alkaline phosphatase activity and osteocalcin content significantly decreased in the miR‐98 mimics group while increased in the miR‐98 inhibitors group and showed no changes in the NC group and Mock group (all P < 0.05). The miR‐98 mimics group showed obviously declined stained red particles and the miR‐98 inhibitors group showed opposite result. After lowering the expression of miR‐98, osteogenic differentiation ability of hBMSCs rose, which was weakened by the transfection with siBMP2. miR‐98 may regulate osteogenic differentiation of hBMSCs by targeting BMP2.

From cell biology to immunology: Controlling metastatic progression of cancer via microRNA regulatory networks

Recently, the study of microRNAs has expanded our knowledge of the fundamental processes of cancer biology and the underlying mechanisms behind tumor metastasis. Extensive research in the fields of microRNA and its novel mechanisms of actions against various cancers has more recently led to the trial of a first cancer-targeted microRNA drug, MRX34. Yet, these microRNAs are mostly being studied and clinically trialed solely based on the understanding of their cell biologic effects, thus, neglecting the important immunologic effects that are sometimes opposite of the cell biologic effects. Here, we summarize both the cell biologic and immunologic effects of various microRNAs and discuss the importance of considering both effects before using them in clinical settings. We stress the importance of understanding the miRNA's effect on cancer metastasis from a "systems" perspective before developing a miRNA-targeted therapeutic in treating cancer metastasis.

Differences in the expression of microRNAs and their predicted gene targets between cauda epididymal and ejaculated boar sperm

Mammalian spermatozoa gradually mature and acquire fertility during the transition from the testis to the caput and cauda epididymis, after which they are stored at the tail of the epididymis and the ampulla of vas deferens. During ejaculation, mixing of spermatozoa with the secretions of accessory sex glands leads to their dilution and changes in their function. Although remarkable progress has been made toward the understanding of changes in spermatozoa biochemistry and function before and after ejaculation, it is unknown whether microRNAs (miRNAs) are involved in regulating the function of spermatozoa during the transition between the cauda epididymis and ejaculation. In this study, 48 miRNAs were selected for analysis on the basis of their potential involvement in spermatogenesis, sperm maturation, and quality parameters markers. The differential expression levels of these 48 miRNAs between the caudal epididymis and fresh ejaculates of boar spermatozoa were determined. We found that 15 miRNAs were significantly differentially expressed (eight downregulated and seven upregulated) between boar cauda epididymal and fresh spermatozoa. Five miRNAs hypothesized to be involved in sperm apoptosis were further tested to demonstrate their influence over the expression of their target mRNAs using quantitative reverse-transcription polymerase chain reaction. Together, our findings suggest that these differentially expressed miRNAs are associated with the functional regulation of spermatozoa between cauda epididymis and ejaculation.

MicroRNA: Small RNA mediators of the brains genomic response to environmental stress

The developmental processes that establish the synaptic architecture of the brain while retaining capacity for activity-dependent remodeling, are complex and involve a combination of genetic and epigenetic influences. Dysregulation of these processes can lead to problems with neural circuitry which manifest in humans as a range of neurodevelopmental syndromes, such as schizophrenia, bipolar disorder and fragile X mental retardation. Recent studies suggest that prenatal, postnatal and intergenerational environmental factors play an important role in the aetiology of stress-related psychopathology. A number of these disorders have been shown to display epigenetic changes in the postmortem brain that reflect early life experience. These changes affect the regulation of gene expression though chromatin remodeling (transcriptional) and post-transcriptional influences, especially small noncoding microRNA (miRNA). These dynamic and influential molecules appear to play an important function in both brain development and its adaption to stress. In this review, we examine the role of miRNA in mediating the brain's response to both prenatal and postnatal environmental perturbations and explore how stress- induced alterations in miRNA expression can regulate the stress response via modulation of the immune system. Given the close relationship between environmental stress, miRNA, and brain development/function, we assert that miRNA hold a significant position at the molecular crossroads between neural development and adaptations to environmental stress. A greater understanding of the dynamics that mediate an individual's predisposition to stress-induced neuropathology has major human health benefits and is an important area of research.

MicroRNA expression profiling in children with different asthma phenotypes

An improved understanding of the molecular mechanisms in asthma through exploring the role of microRNAs may offer promise to reveal new approaches for primary prevention and identification of new therapeutic targets in childhood asthma. The primary goal of this study is to identify the microRNAs that play a role in the pathogenesis of asthma in pediatric age group. The secondary goal is to analyze these microRNAs according to the asthma phenotype, atopic status, and severity of the disease exacerbation. To our knowledge, this is the first research project in the literature which studies the relationship between microRNA expression and the severity of childhood asthma. One hundred children between 6 and 18 years old with a diagnosis of asthma, and 100 age-matched healthy children were enrolled in this study, and the analyses of microRNA expression profiles were performed in the Medical Genetics Laboratories of Ege University between November 2009 and June 2010. The expression of 10 microRNAs were shown to be higher in patients with more severe asthma, and the expression of these microRNAs were also found to be higher in patients who present with more severe acute asthma exacerbation symptoms (P < 0.001). Also, five microRNAs were found to be expressed more than twofold in allergic patients when compared to non-allergic participants (P <0.001). Asthma is one of the best examples of complex genetic diseases, and further studies, which will investigate the relationship between these microRNA's and their target genes, are needed to learn more about the specific roles of microRNAs in respiratory diseases. Pediatr Pulmonol. 2016;51:582-587. © 2015 Wiley Periodicals, Inc.

HIV-1 Infection-Induced Suppression of the Let-7i/IL-2 Axis Contributes to CD4(+) T Cell Death

The mechanisms underlying HIV-1-mediated CD4⁺ T cell depletion are highly complicated. Interleukin-2 (IL-2) is a key cytokine that maintains the survival and proliferation of activated CD4⁺ T cells. IL-2 levels are disturbed during HIV-1 infection, but the underlying mechanism(s) requires further investigation. We have reported that cellular microRNA (miRNA) let-7i upregulates IL-2 expression by targeting the promoter TATA-box region, which functions as a positive regulator. In this study, we found that HIV-1 infection decreases the expression of let-7i in CD4⁺ T cells by attenuating its promoter activity. The reduced let-7i miRNA expression led to a decline in IL-2 levels. A let-7i mimic increased IL-2 expression and subsequently enhanced the resistance of CD4⁺ T cells to HIV-1-induced apoptosis. By contrast, the blockage of let-7i with a specific inhibitor resulted in elevated CD4⁺ T cell apoptosis during HIV-1 infection. Furthermore, by knocking down the expression of IL-2, we found that the let-7i-mediated CD4⁺ T cell resistance to apoptosis during HIV-1 infection was dependent on IL-2 signaling rather than an alternative CD95-mediated cell-death pathway. Taken together, our findings reveal a novel pathway for HIV-1-induced dysregulation of IL-2 cytokines and depletion of CD4⁺ T-lymphocytes.

Peroxisome Proliferator-Activated Receptor γ and microRNA 98 in Hypoxia-Induced Endothelin-1 Signaling

Endothelin-1 (ET-1) plays a critical role in endothelial dysfunction and contributes to the pathogenesis of pulmonary hypertension (PH). We hypothesized that peroxisome proliferator-activated receptor γ (PPARγ) stimulates microRNAs that inhibit ET-1 and pulmonary artery endothelial cell (PAEC) proliferation. The objective of this study was to clarify molecular mechanisms by which PPARγ regulates ET-1 expression in vitro and in vivo. In PAECs isolated from patients with pulmonary arterial hypertension, microRNA (miR)-98 expression was reduced, and ET-1 protein levels and proliferation were increased. Similarly, hypoxia reduced miR-98 and increased ET-1 levels and PAEC proliferation in vitro. In vivo, hypoxia reduced miR-98 expression and increased ET-1 and proliferating cell nuclear antigen (PCNA) levels in mouse lung, derangements that were aggravated by treatment with the vascular endothelial growth factor receptor antagonist Sugen5416. Reporter assays confirmed that miR-98 binds directly to the ET-1 3'-untranslated region. Compared with littermate control mice, miR-98 levels were reduced and ET-1 and PCNA expression were increased in lungs from endothelial-targeted PPARγ knockout mice, whereas miR-98 levels were increased and ET-1 and PCNA expression was reduced in lungs from endothelial-targeted PPARγ-overexpression mice. Gain or loss of PPARγ function in PAECs in vitro confirmed that alterations in PPARγ were sufficient to regulate miR-98, ET-1, and PCNA expression. Finally, PPARγ activation with rosiglitazone regimens that attenuated hypoxia-induced PH in vivo and human PAEC proliferation in vitro restored miR-98 levels. The results of this study show that PPARγ regulates miR-98 to modulate ET-1 expression and PAEC proliferation. These results further clarify molecular mechanisms by which PPARγ participates in PH pathogenesis and therapy.

A Novel Method to Detect Functional microRNA Regulatory Modules by Bicliques Merging

MicroRNAs (miRNAs) are post-transcriptional regulators that repress the expression of their targets. They are known to work cooperatively with genes and play important roles in numerous cellular processes. Identification of miRNA regulatory modules (MRMs) would aid deciphering the combinatorial effects derived from the many-to-many regulatory relationships in complex cellular systems. Here, we develop an effective method called BiCliques Merging (BCM) to predict MRMs based on bicliques merging. By integrating the miRNA/mRNA expression profiles from The Cancer Genome Atlas (TCGA) with the computational target predictions, we construct a weighted miRNA regulatory network for module discovery. The maximal bicliques detected in the network are statistically evaluated and filtered accordingly. We then employed a greedy-based strategy to iteratively merge the remaining bicliques according to their overlaps together with edge weights and the gene-gene interactions. Comparing with existing methods on two cancer datasets from TCGA, we showed that the modules identified by our method are more densely connected and functionally enriched. Moreover, our predicted modules are more enriched for miRNA families and the miRNA-mRNA pairs within the modules are more negatively correlated. Finally, several potential prognostic modules are revealed by Kaplan-Meier survival analysis and breast cancer subtype analysis.

AVAILABILITY

BCM is implemented in Java and available for download in the supplementary materials, which can be found on the Computer Society Digital Library at http://doi.ieeecomputersociety.org/10.1109/ TCBB.2015.2462370.