Transplantation of Exercise-Induced Extracellular Vesicles as a Promising Therapeutic Approach in Ischemic Stroke.

Clinical evidence affirms physical exercise is effective in preventive and rehabilitation approaches for ischemic stroke. This sustainable efficacy is independent of cardiovascular risk factors and associates substantial reprogramming in circulating extracellular vesicles (EVs). The intricate journey of pluripotent exercise-induced EVs from parental cells to the whole-body and infiltration to cerebrovascular entity offers several mechanisms to reduce stroke incidence and injury or accelerate the subsequent recovery. This review delineates the potential roles of EVs as prospective effectors of exercise. The candidate miRNA and peptide cargo of exercise-induced EVs with both atheroprotective and neuroprotective characteristics are discussed, along with their presumed targets and pathway interactions. The existing literature provides solid ground to hypothesize that the rich vesicles link exercise to stroke prevention and rehabilitation. However, there are several open questions about the exercise stressors which may optimally regulate EVs kinetic and boost brain mitochondrial adaptations. This review represents a novel perspective on achieving brain fitness against stroke through transplantation of multi-potential EVs generated by multi-parental cells, which is exceptionally reachable in an exercising body.

Short-term effects of electronic cigarettes on cerebrovascular function: A time course study.

NEW FINDINGS: What is the central question of this study? Acute exposure to electronic cigarettes (Ecigs) triggers abnormal vascular responses in systemic arteries; however, effects on cerebral vessels are poorly understood and time for recovery is not known. We hypothesized that exposure to cigarettes or Ecigs would trigger rapid (<4 h) impairment of the middle cerebral artery (MCA) but that this would resolve by 24 h. What is the main finding and its importance? Cigarettes and Ecigs caused similar degree and duration of MCA impairment. We find it takes ~72 hours after exposure for MCA function to return to normal. This suggests that Ecig use is likely to produce similar adverse vascular health outcomes to those seen with cigarette smoke. ABSTRACT: Temporal influences of electronic cigarettes (Ecigs) on blood vessels are poorly understood. In this study, we evaluated a single episode of cigarette versus Ecig exposure on middle cerebral artery (MCA) reactivity and determined how long after the exposure MCA responses took to return to normal. We hypothesized that cigarette and Ecig exposure would induce rapid (<4 h) reduction in MCA endothelial function and would resolve within 24 h. Sprague-Dawley rats (4 months old) were exposed to either air (n = 5), traditional cigarettes (20 puffs, n = 16) or Ecigs (20-puff group, n = 16; or 60-puff group, n = 12). Thereafter, the cigarette and Ecig groups were randomly assigned for postexposure vessel myography testing on day 0 (D0, 1-4 h postexposure), day 1 (D1, 24-28 h postexposure), day 2 (D2, 48-52 h postexposure) and day 3 (72-76 h postexposure). The greatest effect on endothelium-dependent dilatation was observed within 24 h of exposure (∼50% decline between D0 and D1) for both cigarette and Ecig groups, and impairment persisted with all groups for up to 3 days. Changes in endothelium-independent dilatation responses were less severe (∼27%) and shorter lived (recovering by D2) compared with endothelium-dependent dilatation responses. Vasoconstriction in response to serotonin (5-HT) was similar to endothelium-independent dilatation, with greatest impairment (∼45% for all exposure groups) at D0-D1, returning to normal by D2. These data show that exposure to cigarettes and Ecigs triggers a similar level/duration of cerebrovascular dysfunction after a single exposure. The finding that Ecig (without nicotine) and cigarette (with nicotine) exposure produce the same effects suggesting that nicotine is not likely to be triggering MCA dysfunction, and that vaping (with/without nicotine) has potential to produce the same vascular harm and/or disease as smoking.

Dysphoric Milk Ejection Reflex: The Psychoneurobiology of the Breastfeeding Experience.

Breastfeeding, given its biochemical and physiological basis, is known for its many benefits for both the lactating mother and the infant. Among the many challenges new breastfeeding mothers experience is the feeling of aversion in response to their newborn's suckling which has been termed dysphoric milk-ejection reflex (D-MER). Characterized by intense feelings of dysphoria which may eventually interfere with the mother's ability to breastfeed regularly, evidence suggests both the neurobiological and psychological basis of D-MER in an attempt to explain its complexity. Biologically, breastfeeding is expressed by the intracerebral release of oxytocin, an increased expression of oxytocin receptors in specific brain regions, increased mesocorticolimbic reward region activation, the secretion of prolactin and possibly the inhibition of dopamine. Hence, different theories explain D-MER in terms of disrupted neurotransmitter and hormonal activity. Breastfeeding has also proven to influence mood and stress reactivity in nursing mothers with a potential link with postpartum depression. Psychological theories attempt to explain D-MER from a sociopsychosexual lense shedding light on the significance of mother-infant attachment, the sexualization of the female body and the motherhood experience as a developmental stage in a woman's lifespan. The aim of this review is to provide a literature update of D-MER incorporating both neurobiological and psychological theories calling for raising awareness about the complexity of breastfeeding and for the need for mother-centered interventions for the management of D-MER and other postpartum-specific conditions.

Molecular Analysis of ZNF71 KRAB in Non-Small-Cell Lung Cancer.

Our previous study found that zinc finger protein 71 (ZNF71) mRNA expression was associated with chemosensitivity and its protein expression was prognostic of non-small-cell lung cancer (NSCLC). The Krüppel associated box (KRAB) transcriptional repression domain is commonly present in human zinc finger proteins, which are linked to imprinting, silencing of repetitive elements, proliferation, apoptosis, and cancer. This study revealed that ZNF71 KRAB had a significantly higher expression than the ZNF71 KRAB-less isoform in NSCLC tumors (n = 197) and cell lines (n = 117). Patients with higher ZNF71 KRAB expression had a significantly worse survival outcome than patients with lower ZNF71 KRAB expression (log-rank p = 0.04; hazard ratio (HR): 1.686 [1.026, 2.771]), whereas ZNF71 overall and KRAB-less expression levels were not prognostic in the same patient cohort. ZNF71 KRAB expression was associated with epithelial-to-mesenchymal transition (EMT) in both patient tumors and cell lines. ZNF71 KRAB was overexpressed in NSCLC cell lines resistant to docetaxel and paclitaxel treatment compared to chemo-sensitive cell lines, consistent with its association with poor prognosis in patients. Therefore, ZNF71 KRAB isoform is a more effective prognostic factor than ZNF71 overall and KRAB-less expression for NSCLC. Functional analysis using CRISPR-Cas9 and RNA interference (RNAi) screening data indicated that a knockdown/knockout of ZNF71 did not significantly affect NSCLC cell proliferation in vitro.

Intermittent Lipopolysaccharide Exposure Significantly Increases Cortical Infarct Size and Impairs Autophagy.

Globally, stroke is a leading cause of death and disability. Traditional risk factors like hypertension, diabetes, and obesity do not fully account for all stroke cases. Recent infection is regarded as changes in systemic immune signaling, which can increase thrombosis formation and other stroke risk factors. We have previously shown that administration of lipopolysaccharide (LPS) 30-minutes prior to stroke increases in infarct volume. In the current study, we found that animals intermittently exposed to LPS have larger cortical infarcts when compared to saline controls. To elucidate the mechanism behind this phenomenon, several avenues were investigated. We observed significant upregulation of tumor necrosis factor-alpha (TNF-α) mRNA, especially in the ipsilateral hemisphere of both saline and LPS exposed groups compared to sham surgery animals. We also observed significant reductions in expression of genes involved in autophagy in the ipsilateral hemisphere of LPS stroke animals. In addition, we assessed DNA methylation of autophagy genes and observed a significant increase in the ipsilateral hemisphere of LPS stroke animals. Intermittent exposure to LPS increases cortical infarct volume, downregulates autophagy genes, and induces hypermethylation of the corresponding CpG islands. These data suggest that intermittent immune activation may deregulate epigenetic mechanisms and promote neuropathological outcomes after stroke.

Disruption of metabolic, sleep, and sensorimotor functional outcomes in a female transgenic mouse model of Alzheimer's disease.

Alzheimer's Disease (AD) is the most prevalent form of dementia globally, and the number of individuals with AD diagnosis is expected to double by 2050. Numerous preclinical AD studies have shown that AD neuropathology accompanies alteration in learning and memory. However, less attention has been given to alterations in metabolism, sleep, and sensorimotor functional outcomes during AD pathogenesis. The objective of this study was to elucidate the extent to which metabolic activity, sleep-wake cycle, and sensorimotor function is impaired in APPSwDI/Nos2-/- (CVN-AD) transgenic mice. Female mice were used in this study because AD is more prevalent in women compared to men. We hypothesized that the presence of AD neuropathology in CVN-AD mice would accompany alterations in metabolic activity, sleep, and sensorimotor function. Our results showed that CVN-AD mice had significantly decreased energy expenditure compared to wild-type (WT) mice. An examination of associated functional outcome parameters showed that sleep activity was elevated during the awake (dark) cycle and as well as an overall decrease in spontaneous locomotor activity. An additional functional parameter, the nociceptive response to thermal stimuli, was also impaired in CVN-AD mice. Collectively, our results demonstrate CVN-AD mice exhibit alterations in functional parameters that resemble human-AD clinical progression.

Medroxyprogesterone Acetate Impairs Amyloid Beta Degradation in a Matrix Metalloproteinase-9 Dependent Manner.

Despite the extensive use of hormonal methods as either contraception or menopausal hormone therapy (HT), there is very little known about the potential effects of these compounds on the cellular processes of the brain. Medroxyprogesterone Acetate (MPA) is a progestogen used globally in the hormonal contraceptive, Depo Provera, by women in their reproductive prime and is a major compound found in HT formulations used by menopausal women. MPA promotes changes in the circulating levels of matrix metalloproteinases (MMPs), such as MMP-9, in the endometrium, yet limited literature studying the effects of MPA on neurons and astroglia cells has been conducted. Additionally, the dysregulation of MMPs has been implicated in the pathology of Alzheimer's disease (AD), where inhibiting the secretion of MMP-9 from astroglia reduces the proteolytic degradation of amyloid-beta. Thus, we hypothesize that exposure to MPA disrupts proteolytic degradation of amyloid-beta through the downregulation of MMP-9 expression and subsequent secretion. To assess the effect of progestins on MMP-9 and amyloid-beta, in vitro, C6 rat glial cells were exposed to MPA for 48 h and then the enzymatic, secretory, and amyloid-beta degrading capacity of MMP-9 was assessed from the conditioned culture medium. We found that MPA treatment inhibited transcription of MMP-9, which resulted in a subsequent decrease in the production and secretion of MMP-9 protein, in part through the glucocorticoid receptor. Additionally, we investigated the consequences of amyloid beta-degrading activity and found that MPA treatment decreased proteolytic degradation of amyloid-beta. Our results suggest MPA suppresses amyloid-beta degradation in an MMP-9-dependent manner, in vitro, and potentially compromises the clearance of amyloid-beta in vivo.

Loss of tissue-nonspecific alkaline phosphatase (TNAP) enzyme activity in cerebral microvessels is coupled to persistent neuroinflammation and behavioral deficits in late sepsis.

Sepsis is a host response to systemic inflammation and infection that may lead to multi-organ dysfunction and eventual death. While acute brain dysfunction is common among all sepsis patients, chronic neurological impairment is prevalent among sepsis survivors. The brain microvasculature has emerged as a major determinant of sepsis-associated brain dysfunction, yet the mechanisms that underlie its associated neuroimmune perturbations and behavioral deficits are not well understood. An emerging body of data suggests that inhibition of tissue-nonspecific alkaline phosphatase (TNAP) enzyme activity in cerebral microvessels may be associated with changes in endothelial cell barrier integrity. The objective of this study was to elucidate the connection between alterations in cerebrovascular TNAP enzyme activity and brain microvascular dysfunction in late sepsis. We hypothesized that the disruption of TNAP enzymatic activity in cerebral microvessels would be coupled to the sustained loss of brain microvascular integrity, elevated neuroinflammatory responses, and behavioral deficits. Male mice were subjected to cecal ligation and puncture (CLP), a model of experimental sepsis, and assessed up to seven days post-sepsis. All mice were observed daily for sickness behavior and underwent behavioral testing. Our results showed a significant decrease in brain microvascular TNAP enzyme activity in the somatosensory cortex and spinal cord of septic mice but not in the CA1 and CA3 hippocampal regions. Furthermore, we showed that loss of cerebrovascular TNAP enzyme activity was coupled to a loss of claudin-5 and increased perivascular IgG infiltration in the somatosensory cortex. Analyses of whole brain myeloid and T-lymphoid cell populations also revealed a persistent elevation of infiltrating leukocytes, which included both neutrophil and monocyte myeloid derived suppressor cells (MDSCs). Regional analyses of the somatosensory cortex, hippocampus, and spinal cord revealed significant astrogliosis and microgliosis in the cortex and spinal cord of septic mice that was accompanied by significant microgliosis in the CA1 and CA3 hippocampal regions. Assessment of behavioral deficits revealed no changes in learning and memory or evoked locomotion. However, the hot plate test uncovered a novel anti-nociceptive phenotype in our septic mice, and we speculate that this phenotype may be a consequence of sustained GFAP astrogliosis and loss of TNAP activity in the somatosensory cortex and spinal cord of septic mice. Taken together, these results demonstrate that the loss of TNAP enzyme activity in cerebral microvessels during late sepsis is coupled to sustained neuroimmune dysfunction which may underlie, in part, the chronic neurological impairments observed in sepsis survivors.

Systemic inhibition of tissue-nonspecific alkaline phosphatase alters the brain-immune axis in experimental sepsis.

Tissue-nonspecific alkaline phosphatase (TNAP) is a ubiquitous enzyme present in many cells and tissues, including the central nervous system. Yet its functions at the brain-immune axis remain unclear. The goal of this study was to use a novel small molecular inhibitor of TNAP, SBI-425, to interrogate the function of TNAP in neuroimmune disorders. Following intraperitoneal (IP) administration of SBI-425, mass spectrometry analysis revealed that the SBI-425 does not cross the blood-brain barrier (BBB) in healthy mice. To elucidate the role of TNAP at the brain-immune axis, mice were subjected to experimental sepsis and received either vehicle or SBI-425 (25 mg/kg, IP) daily for 7 days. While SBI-425 administration did not affect clinical severity outcomes, we found that SBI-425 administration suppressed CD4 + Foxp3+ CD25- and CD8 + Foxp3+ CD25- splenocyte T-cell populations compared to controls. Further evaluation of SBI-425's effects in the brain revealed that TNAP activity was suppressed in the brain parenchyma of SBI-425-treated mice compared to controls. When primary brain endothelial cells were treated with a proinflammatory stimulus the addition of SBI-425 treatment potentiated the loss of barrier function in BBB endothelial cells. To further demonstrate a protective role for TNAP at endothelial barriers within this axis, transgenic mice with a conditional overexpression of TNAP were subjected to experimental sepsis and found to have increased survival and decreased clinical severity scores compared to controls. Taken together, these results demonstrate a novel role for TNAP activity in shaping the dynamic interactions within the brain-immune axis.

Caspase-11 Mediates Neutrophil Chemotaxis and Extracellular Trap Formation During Acute Gouty Arthritis Through Alteration of Cofilin Phosphorylation.

Gout is characterized by attacks of arthritis with hyperuricemia and monosodium urate (MSU) crystal-induced inflammation within joints. Innate immune responses are the primary drivers for tissue destruction and inflammation in gout. MSU crystals engage the Nlrp3 inflammasome, leading to the activation of caspase-1 and production of IL-1ß and IL-18 within gout-affected joints, promoting the influx of neutrophils and monocytes. Here, we show that caspase-11-/- mice and their derived macrophages produce significantly reduced levels of gout-specific cytokines including IL-1ß, TNFα, IL-6, and KC, while others like IFNγ and IL-12p70 are not altered. IL-1ß induces the expression of caspase-11 in an IL-1 receptor-dependent manner in macrophages contributing to the priming of macrophages during sterile inflammation. The absence of caspase-11 reduced the ability of macrophages and neutrophils to migrate in response to exogenously injected KC in vivo. Notably, in vitro, caspase-11-/- neutrophils displayed random migration in response to a KC gradient when compared to their WT counterparts. This phenotype was associated with altered cofilin phosphorylation. Unlike their wild-type counterparts, caspase-11-/- neutrophils also failed to produce neutrophil extracellular traps (NETs) when treated with MSU. Together, this is the first report demonstrating that caspase-11 promotes neutrophil directional trafficking and function in an acute model of gout. Caspase-11 also governs the production of inflammasome-dependent and -independent cytokines from macrophages. Our results offer new, previously unrecognized functions for caspase-11 in macrophages and neutrophils that may apply to other neutrophil-mediated disease conditions besides gout.

Constitutive AKT Activity Predisposes Lung Fibrosis by Regulating Macrophage, Myofibroblast and Fibrocyte Recruitment and Changes in Autophagy.

The etiology and pathogenesis of pulmonary fibrosis is poorly understood. We and others reported that M-CSF/CSF-1, M-CSF-R and downstream AKT activation plays an important role in lung fibrosis in mice models and in IPF patients. To understand potential molecular pathways used by M-CSF-R activation to direct lung fibrosis, we used a novel transgenic mouse model that expresses a constitutively-active form of AKT, myristoylated AKT (Myr-Akt), driven by the c-fms (M-CSF-R) promoter. We were particularly interested in the basal immune state of the lungs of these Myr-Akt mice to assess M-CSF-R-related priming for lung fibrosis. In support of a priming effect, macrophages isolated from the lungs of unchallenged Myr-Akt mice displayed an M2-tropism, enhanced co-expression of M-CSF-R and α-SMA, reduced autophagy reflected by reduced expression of the key autophagy genes Beclin-1, MAP1-Lc3a(Lc3a), and MAP1-Lc3b(Lc3b), and increased p62/STSQM1 expression compared with littermate WT mice. Furthermore, Myr-Akt mice had more basal circulating fibrocytes than WT mice. Lastly, upon bleomycin challenge, Myr-Akt mice showed enhanced collagen deposition, increased F4/80+ and CD45+ cells, reduced autophagy genes Beclin-1, Lc3a, and Lc3b expression, and a shorter life-span than WT littermates. These data provide support that M-CSF-R/AKT activation may have a priming effect which can predispose lung tissue to pulmonary fibrosis.

Circulating extracellular vesicle content reveals de novo DNA methyltransferase expression as a molecular method to predict septic shock.

Extracellular vesicles (EVs) are mRNA-containing cell fragments shed into circulation during pathophysiological events. DNA methyltransferases (DNMT1, DNMT3A, and DNMT3B) regulate gene expression by modifying DNA methylation and altering transcription. Sepsis is a systemic insult resulting in vascular dysfunction, which can lead to shock and death. We analysed plasma from ICU patients for circulating EV numbers, defined as particles isolated from 1 mL plasma at 21,000xg, and DNMTs mRNA content as prognostic markers of septic shock. Compared to plasma from critically ill patients with or without sepsis, plasma from septic shock patients contained more EVs per mL, expressed as total DNMTs mRNAs over 5 days, and more individual DNMT mRNAs at each day. A comparison of EV-DNMT1 (maintenance methylation) with EV-DNMT3A+DNMT3B (de novo methylation) expression correlated highly with severity, and EVs from septic shock patients carried more total DNMT mRNAs and more DNMT3A+DNMT3B mRNAs than control or sepsis EVs. Total plasma EVs also correlated with sepsis severity. EV-DNMT mRNAs load, when coupled with total plasma EV number, may be a novel method to diagnose septic shock upon ICU admittance and offer opportunities to more precisely intervene with standard therapy or other targeted interventions to regulate EV release and/or specific DNMT activity.

Methylomic correlates of autophagy activity in cystic fibrosis.

Autophagy is a highly regulated, biological process that provides energy during periods of stress and starvation. This conserved process also acts as a defense mechanism and clears microbes from the host cell. Autophagy is impaired in Cystic Fibrosis (CF) patients and CF mice, as their cells exhibit low expression levels of essential autophagy molecules. The genetic disorder in CF is due to mutations in the cystic fibrosis transmembrane conductance regulator (cftr) gene that encodes for a chloride channel. CF patients are particularly prone to infection by pathogens that are otherwise cleared by autophagy in healthy immune cells including Burkholderia cenocepacia (B. cenocepacia). The objective of this study is to determine the mechanism underlying weak autophagic activity in CF macrophages and find therapeutic targets to correct it. Using reduced representation bisulfite sequencing (RRBS) to determine DNA methylation profile, we found that the promoter regions of Atg12 in CF macrophages are significantly more methylated than in the wild-type (WT) immune cells, accompanied by low protein expression. The natural product epigallocatechin-3-gallate (EGCG) significantly reduced the methylation of Atg12 promoter improving its expression. Accordingly, EGCG restricted B. cenocepacia replication within CF mice and their derived macrophages by improving autophagy and preventing dissemination. In addition, EGCG improved the function of CFTR protein. Altogether, utilizing RRBS for the first time in the CF field revealed a previously unrecognized mechanism for reduced autophagic activity in CF. Our data also offers a mechanism by which EGCG exerts its positive effects in CF.

The expression of Mirc1/Mir17-92 cluster in sputum samples correlates with pulmonary exacerbations in cystic fibrosis patients.

INTRODUCTION: Cystic fibrosis (CF) is a multi-organ disorder characterized by chronic sino-pulmonary infections and inflammation. Many patients with CF suffer from repeated pulmonary exacerbations that are predictors of worsened long-term morbidity and mortality. There are no reliable markers that associate with the onset or progression of an exacerbation or pulmonary deterioration. Previously, we found that the Mirc1/Mir17-92a cluster which is comprised of 6 microRNAs (Mirs) is highly expressed in CF mice and negatively regulates autophagy which in turn improves CF transmembrane conductance regulator (CFTR) function. Therefore, here we sought to examine the expression of individual Mirs within the Mirc1/Mir17-92 cluster in human cells and biological fluids and determine their role as biomarkers of pulmonary exacerbations and response to treatment. METHODS: Mirc1/Mir17-92 cluster expression was measured in human CF and non-CF plasma, blood-derived neutrophils, and sputum samples. Values were correlated with pulmonary function, exacerbations and use of CFTR modulators. RESULTS: Mirc1/Mir17-92 cluster expression was not significantly elevated in CF neutrophils nor plasma when compared to the non-CF cohort. Cluster expression in CF sputum was significantly higher than its expression in plasma. Elevated CF sputum Mirc1/Mir17-92 cluster expression positively correlated with pulmonary exacerbations and negatively correlated with lung function. Patients with CF undergoing treatment with the CFTR modulator Ivacaftor/Lumacaftor did not demonstrate significant change in the expression Mirc1/Mir17-92 cluster after six months of treatment. CONCLUSIONS: Mirc1/Mir17-92 cluster expression is a promising biomarker of respiratory status in patients with CF including pulmonary exacerbation.

Of mice and men: correlations between microRNA-17∼92 cluster expression and promoter methylation in severe bronchopulmonary dysplasia.

We previously demonstrated that decreased miR-17∼92 cluster expression was 1) present in lungs from human infants who died with bronchopulmonary dysplasia (BPD); 2) inversely correlated with DNA methyltransferase (DNMT) expression and promoter methylation; and 3) correlated with a subsequent diagnosis of BPD at 36 wk gestational age. We tested the hypothesis that plasma miR-17 levels would be lowest in infants who ultimately develop severe BPD. Secondly, we utilized our well-characterized murine model of severe BPD that combines perinatal inflammation with postnatal hyperoxia to test the hypothesis that alterations in lung miR-17∼92, DNMT, and promoter methylation in our model would mirror our findings in tissues from premature human infants. Plasma was obtained during the first 5 days of life from premature infants born ≤32 wk gestation. Lung tissues were harvested from mice exposed to maternal inflammation and neonatal hyperoxia for 14 days after birth. miR-17∼92 cluster expression and DNA methyltransferase expression were measured by qRT-PCR, and promoter methylation was assessed by Methyl-Profiler assay. Plasma miR-17 levels are significantly lower in the first week of life in human infants who develop severe BPD compared with mild or moderate BPD. Data from our severe BPD murine model reveal that lung miR-17∼92 cluster expression is significantly attenuated, and levels inversely correlated with DNMT expression and miR-17∼92 cluster promoter methylation. Collectively, our data support a plausible role for epigenetically altered miR-17∼92 cluster in the pathogenesis of severe BPD.

Elevated Mirc1/Mir17-92 cluster expression negatively regulates autophagy and CFTR (cystic fibrosis transmembrane conductance regulator) function in CF macrophages.

Cystic fibrosis (CF) is a fatal, genetic disorder that critically affects the lungs and is directly caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, resulting in defective CFTR function. Macroautophagy/autophagy is a highly regulated biological process that provides energy during periods of stress and starvation. Autophagy clears pathogens and dysfunctional protein aggregates within macrophages. However, this process is impaired in CF patients and CF mice, as their macrophages exhibit limited autophagy activity. The study of microRNAs (Mirs), and other noncoding RNAs, continues to offer new therapeutic targets. The objective of this study was to elucidate the role of Mirs in dysregulated autophagy-related genes in CF macrophages, and then target them to restore this host-defense function and improve CFTR channel function. We identified the Mirc1/Mir17-92 cluster as a potential negative regulator of autophagy as CF macrophages exhibit decreased autophagy protein expression and increased cluster expression when compared to wild-type (WT) counterparts. The absence or reduced expression of the cluster increases autophagy protein expression, suggesting the canonical inverse relationship between Mirc1/Mir17-92 and autophagy gene expression. An in silico study for targets of Mirs that comprise the cluster suggested that the majority of the Mirs target autophagy mRNAs. Those targets were validated by luciferase assays. Notably, the ability of macrophages expressing mutant F508del CFTR to transport halide through their membranes is compromised and can be restored by downregulation of these inherently elevated Mirs, via restoration of autophagy. In vivo, downregulation of Mir17 and Mir20a partially restored autophagy expression and hence improved the clearance of Burkholderia cenocepacia. Thus, these data advance our understanding of mechanisms underlying the pathobiology of CF and provide a new therapeutic platform for restoring CFTR function and autophagy in patients with CF.

Aging is associated with hypermethylation of autophagy genes in macrophages.

Autophagy is a biological process characterized by self-digestion and involves induction of autophagosome formation, leading to degradation of autophagic cargo. Aging is associated with the reduction of autophagy activity leading to neurodegenerative disorders, chronic inflammation, and susceptibility to infection; however, the underlying mechanism is unclear. DNA methylation by DNA methyltransferases reduces the expression of corresponding genes. Since macrophages are major players in inflammation and defense against infection we determined the differences in methylation of autophagy genes in macrophages derived from young and aged mice. We found that promoter regions of Atg5 and LC3B are hypermethylated in macrophages from aged mice and this is accompanied by low gene expression. Treatment of aged mice and their derived macrophages with methyltransferase inhibitor (2)-epigallocatechin-3-gallate (EGCG) or specific DNA methyltransferase 2 (DNMT2) siRNA restored the expression of Atg5 and LC3 in vivo and in vitro. Our study builds a foundation for the development of novel therapeutics aimed to improve autophagy in the elderly population and suggests a role for DNMT2 in DNA methylation activities.

Attenuation of miR-17∼92 Cluster in Bronchopulmonary Dysplasia.

RATIONALE: Bronchopulmonary dysplasia remains a significant cause of neonatal morbidity; however, the identification of novel targets to predict or prevent the development of bronchopulmonary dysplasia remains elusive. Proper microRNA (miR)-17∼92 cluster is necessary for normal lung development, and alterations in expression are reported in other pulmonary diseases. The overall hypothesis for our work is that altered miR-17∼92 cluster expression contributes to the molecular pathogenesis of bronchopulmonary dysplasia. OBJECTIVES: The current studies tested the hypothesis that alterations in miR-17∼92 cluster and DNA methyltransferase expression are present in bronchopulmonary dysplasia. METHODS: miR-17∼92 cluster expression, promoter methylation, and DNA methyltransferase expression were determined in autopsy lung samples obtained from premature infants who died with bronchopulmonary dysplasia, or from term/near-term infants who died from nonrespiratory causes. Expression of miR-17∼92 cluster members miR-17 and -19b was measured in plasma samples collected in the first week of life from a separate cohort of preterm infants at a second institution in whom bronchopulmonary dysplasia was diagnosed subsequently. MEASUREMENTS AND MAIN RESULTS: Autopsy tissue data indicated that miR-17∼92 expression is significantly lower in bronchopulmonary dysplasia lungs and is inversely correlated with promoter methylation and DNA methyltransferase expression when compared with that of control subjects without bronchopulmonary dysplasia. Plasma sample analyses indicated that miR-17 and -19b expression was decreased in infants who subsequently developed bronchopulmonary dysplasia. CONCLUSIONS: Our data are the first to demonstrate altered expression of the miR-17∼92 cluster in bronchopulmonary dysplasia. The consistency between our autopsy and plasma findings further support our working hypothesis that the miR-17∼92 cluster contributes to the molecular pathogenesis of bronchopulmonary dysplasia.

MicroRNA-133a engineered mesenchymal stem cells augment cardiac function and cell survival in the infarct heart.

: Cardiovascular disease is the number 1 cause of morbidity and mortality in the United States. The most common manifestation of cardiovascular disease is myocardial infarction (MI), which can ultimately lead to congestive heart failure. Cell therapy (cardiomyoplasty) is a new potential therapeutic treatment alternative for the damaged heart. Recent preclinical and clinical studies have shown that mesenchymal stem cells (MSCs) are a promising cell type for cardiomyoplasty applications. However, a major limitation is the poor survival rate of transplanted stem cells in the infarcted heart. miR-133a is an abundantly expressed microRNA (miRNA) in the cardiac muscle and is downregulated in patients with MI. We hypothesized that reprogramming MSCs using miRNA mimics (double-stranded oligonucleotides) will improve survival of stem cells in the damaged heart. MSCs were transfected with miR-133a mimic and antagomirs, and the levels of miR-133a were measured by quantitative real-time polymerase chain reaction. Rat hearts were subjected to MI and MSCs transfected with miR-133a mimic or antagomir were implanted in the ischemic hearts. Four weeks after MI, cardiac function, cardiac fibrosis, miR-133a levels, and apoptosis-related genes (Apaf-1, Caspase-9, and Caspase-3) were measured in the heart. We found that transfecting MSCs with miR-133a mimic improves survival of MSCs as determined by the MTT assay. Similarly, transplantation of miR-133a mimic transfected MSCs in rat hearts subjected to MI led to a significant increase in cell engraftment, cardiac function, and decreased fibrosis when compared with MSCs only or MI groups. At the molecular level, quantitative real-time polymerase chain reaction data demonstrated a significant decrease in expression of the proapoptotic genes; Apaf-1, caspase-9, and caspase-3 in the miR-133a mimic transplanted group. Furthermore, luciferase reporter assay confirmed that miR-133a is a direct target for Apaf-1. Overall, bioengineering of stem cells through miRNAs manipulation could potentially improve the therapeutic outcome of patients undergoing stem cell transplantation for MI.

MicroRNA 17-92 cluster mediates ETS1 and ETS2-dependent RAS-oncogenic transformation.

The ETS-family transcription factors Ets1 and Ets2 are evolutionarily conserved effectors of the RAS/ERK signaling pathway, but their function in Ras cellular transformation and biology remains unclear. Taking advantage of Ets1 and Ets2 mouse models to generate Ets1/Ets2 double knockout mouse embryonic fibroblasts, we demonstrate that deletion of both Ets1 and Ets2 was necessary to inhibit HrasG12V induced transformation both in vitro and in vivo. HrasG12V expression in mouse embryonic fibroblasts increased ETS1 and ETS2 expression and binding to cis-regulatory elements on the c-Myc proximal promoter, and consequently induced a robust increase in MYC expression. The expression of the oncogenic microRNA 17-92 cluster was increased in HrasG12V transformed cells, but was significantly reduced when ETS1 and ETS2 were absent. MYC and ETS1 or ETS2 collaborated to increase expression of the oncogenic microRNA 17-92 cluster in HrasG12V transformed cells. Enforced expression of exogenous MYC or microRNA 17-92 rescued HrasG12V transformation in Ets1/Ets2-null cells, revealing a direct function for MYC and microRNA 17-92 in ETS1/ETS2-dependent HrasG12V transformation.