miR-29c induction contributes to downregulation of vascular extracellular matrix proteins by glucocorticoids

The molecular mechanisms in prenatal drug exposure-induced fetal programmed adult cardiovascular disease

The "developmental origins of health and disease" (DOHaD) hypothesis posits that early-life environmental exposures have a lasting impact on individual's health and permanently shape growth, structure, and metabolism. This reprogramming, which results from fetal stress, is believed to contribute to the development of adulthood cardiovascular diseases such as hypertension, coronary artery disease, heart failure, and increased susceptibility to ischemic injuries. Recent studies have shown that prenatal exposure to drugs, such as glucocorticoids, antibiotics, antidepressants, antiepileptics, and other toxins, increases the risk of adult-onset cardiovascular diseases. In addition, observational and animal experimental studies have demonstrated the association between prenatal drug exposure and the programming of cardiovascular disease in the offspring. The molecular mechanisms underlying these effects are still being explored but are thought to involve metabolism dysregulation. This review summarizes the current evidence on the relationship between prenatal drug exposure and the risk of adult cardiovascular disorders. Additionally, we present the latest insights into the molecular mechanisms that lead to programmed cardiovascular phenotypes after prenatal drug exposure.

Emerging mechanisms of elastin transcriptional regulation

Elastin provides recoil to tissues that stretch such as the lung, blood vessels, and skin. It is deposited in a brief window starting in the prenatal period and extending to adolescence in vertebrates, and then slowly turns over. Elastin insufficiency is seen in conditions such as Williams-Beuren syndrome and elastin-related supravalvar aortic stenosis, which are associated with a range of vascular and connective tissue manifestations. Regulation of the elastin (ELN) gene occurs at multiple levels including promoter activation/inhibition, mRNA stability, interaction with microRNAs, and alternative splicing. However, these mechanisms are incompletely understood. Better understanding of the processes controlling ELN gene expression may improve medicine's ability to intervene in these rare conditions, as well as to replace age-associated losses by re-initiating elastin production. This review describes what is known about the ELN gene promoter structure, transcriptional regulation by cytokines and transcription factors, and posttranscriptional regulation via mRNA stability and micro-RNA and highlights new approaches that may influence regenerative medicine.

Experimental Manipulation of Corticosterone Does Not Affect Venom Composition or Functional Activity in Free-Ranging Rattlesnakes

AbstractVenom is an integral feeding trait in many animal species. Although venom often varies ontogenetically, little is known about the proximate physiological mediators of venom variation within individuals. The glucocorticoid hormone corticosterone (CORT) can alter the transcription and activation of proteins, including homologues of snake venom components such as snake venom metalloproteinases (SVMPs) and phospholipase A₂ (PLA₂). CORT is endogenously produced by snakes, varies seasonally and also in response to stress, and is a candidate endogenous mediator of changes in venom composition and functional activity. Here, we tested the hypothesis that CORT induces changes in snake venom by sampling the venom of wild adult rattlesnakes before and after they were treated with either empty (control) or CORT-filled (treatment) Silastic implants. We measured longitudinal changes in whole-venom composition, whole-venom total protein content, and enzymatic activity of SVMP and PLA₂ components of venom. We also assessed the within-individual repeatability of venom components. Despite successfully elevating plasma CORT in the treatment group, we found no effect of CORT treatment or average plasma CORT level on any venom variables measured. Except for total protein content, venom components were highly repeatable within individuals ([Formula: see text]). Our results indicate that the effects of CORT, a hormone commonly associated with stress and metabolic functions, in adult rattlesnake venom are negligible. Our findings bode well for venom researchers and biomedical applications that rely on the consistency of venoms produced from potentially stressed individuals and provide an experimental framework for future studies of proximate mediators of venom variation across an individual's life span.

Non-coding RNAs modulate function of extracellular matrix proteins

The extracellular matrix (ECM) creates a multifaceted system for the interaction of diverse structural proteins, matricellular molecules, proteoglycans, hyaluronan, and various glycoproteins that collaborate and bind with each other to produce a bioactive polymer. Alterations in the composition and configuration of ECM elements influence the cellular phenotype, thus participating in the pathogenesis of several human disorders. Recent studies indicate the crucial roles of non-coding RNAs in the modulation of ECM. Several miRNAs such as miR-21, miR-26, miR-19, miR-140, miR-29, miR-30, miR-133 have been dysregulated in disorders that are associated with disruption or breakdown of the ECM. Moreover, expression of MALAT1, PVT1, SRA1, n379519, RMRP, PFL, TUG1, TM1P3, FAS-AS1, PART1, XIST, and expression of other lncRNAs is altered in disorders associated with the modification of ECM components. In the current review, we discuss the role of lncRNAs and miRNAs in the modification of ECM and their relevance with the pathophysiology of human disorders such as cardiac/ lung fibrosis, cardiomyopathy, heart failure, asthma, osteoarthritis, and cancers.

Maternal Undernutrition Modulates Neonatal Rat Cerebrovascular Structure, Function, and Vulnerability to Mild Hypoxic-Ischemic Injury via Corticosteroid-Dependent and -Independent Mechanisms

The present study explored the hypothesis that an adverse intrauterine environment caused by maternal undernutrition (MUN) acted through corticosteroid-dependent and -independent mechanisms to program lasting functional changes in the neonatal cerebrovasculature and vulnerability to mild hypoxic-ischemic (HI) injury. From day 10 of gestation until term, MUN and MUN-metyrapone (MUN-MET) group rats consumed a diet restricted to 50% of calories consumed by a pair-fed control; and on gestational day 11 through term, MUN-MET groups received drinking water containing MET (0.5 mg/mL), a corticosteroid synthesis inhibitor. P9/P10 pups underwent unilateral carotid ligation followed 24 h later by 1.5 h exposure to 8% oxygen (HI treatment). An ELISA quantified MUN-, MET-, and HI-induced changes in circulating levels of corticosterone. In P11/P12 pups, MUN programming promoted contractile differentiation in cerebrovascular smooth muscle as determined by confocal microscopy, modulated calcium-dependent contractility as revealed by cerebral artery myography, enhanced vasogenic edema formation as indicated by T2 MRI, and worsened neurobehavior MUN unmasked HI-induced improvements in open-field locomotion and in edema resolution, alterations in calcium-dependent contractility and promotion of contractile differentiation. Overall, MUN imposed multiple interdependent effects on cerebrovascular smooth muscle differentiation, contractility, edema formation, flow-metabolism coupling and neurobehavior through pathways that both required, and were independent of, gestational corticosteroids. In light of growing global patterns of food insecurity, the present study emphasizes that infants born from undernourished mothers may experience greater risk for developing neonatal cerebral edema and sensorimotor impairments possibly through programmed changes in neonatal cerebrovascular function.

Functional role of the long noncoding RNA X-inactive specific transcript in leiomyoma pathogenesis

OBJECTIVE

To determine the expression and functional roles of a long noncoding RNA (lncRNA) X-inactive specific transcript (XIST) in leiomyoma.

DESIGN

Experimental study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing hysterectomy for leiomyoma.

INTERVENTION(S)

Overexpression and underexpression of XIST; blockade of specific protein 1 (SP1).

MAIN OUTCOME MEASURE(S)

Expression of XIST in leiomyoma and its effects on microRNA 29c (miR-29c), miR-200c, and their targets.

RESULT(S)

Leiomyoma expressed statistically significantly more XIST as compared with matched myometrium, independent of race/ethnicity and menstrual cycle phase. By use of a three-dimensional spheroid culture system, we found reduced XIST levels in leiomyoma smooth muscle cells (LSMC) after treatment with 17β-estradiol, progesterone, and their combination. The expression of XIST was down-regulated by treatment with the SP1-inhibitor mithramycin A and SP1 small interfering RNA. Knockdown of XIST resulted in inhibition of cell proliferation, up-regulation of miR-29c and miR-200c, and a concomitant inhibition of the target genes of these miRNAs, namely collagen type I (COL1A1), collagen type III (COL3A1), and fibronectin (FN1). By contrast, overexpression of XIST in myometrium smooth muscle cells repressed miR-29c and miR-200c, and induced COL1A1, COL3A1, and FN1 levels. By use of RNA immunoprecipitation analysis we confirmed XIST has sponge activity over miR-29c and miR-200c, which is more pronounced in leiomyoma as compared with myometrium.

CONCLUSION(S)

Our data demonstrate that increased expression of XIST in leiomyoma results in reduced expression of miR-29c and miR-200c with a consequent up-regulation of the genes targeted by these microRNAs including COL1A1, COL3A1, and FN1, which play key roles in extracellular matrix accumulation associated with fibroids.

Prospective of extracellular matrix and drug correlations in disease management

The extracellular matrix (ECM) comprises of many structural molecules that constitute the extracellular environment. ECM molecules are characterized by specific features like diversity, complexity and signaling, which are also results of improvement or development of disease mediated by some physiological changes. Several drugs have also been used to manage diseases and they have been reported to modulate ECM assembly, including physiological changes, beyond their primary targets and ECM metabolism. This review highlights the alteration of ECM environment for diseases and effect of different classes of drugs like nonsteroidal anti-inflammatory drugs, immune suppressant drug, steroids on ECM or its components. Thus, it is summarized from previously conducted researches that diseases can be managed by targeting specific components of ECM which are involved in the pathophysiology of diseases. Moreover, the drug delivery focused on targeting the ECM components also has the potential for the discovery of targeted and site specific release of drugs. Therefore, ECM or its components could be future targets for the development of new drugs for controlling various disease conditions including neurodegenerative diseases and cancers.

Mechanism underlying increased cardiac extracellular matrix deposition in perinatal nicotine-exposed offspring

Although increased predisposition to cardiac fibrosis and cardiac dysfunction has been demonstrated in the perinatally nicotine-exposed heart, the underlying mechanisms remain unclear. With the use of a well-established rat model and cultured primary neonatal rat cardiac fibroblasts, the effect of perinatal nicotine exposure on offspring heart extracellular matrix deposition and the likely underlying mechanisms were investigated. Perinatal nicotine exposure resulted in increased collagen type I (COL1A1) and III (COL3A1) deposition along with a decrease in miR-29 family and an increase in long noncoding RNA myocardial infarction-associated transcript (MIAT) levels in offspring heart. Nicotine treatment of isolated primary neonatal rat cardiac fibroblasts suggested that these effects were mediated via nicotinic acetylcholine receptors including α7 and the induced collagens accumulation was reversed by a gain-of function of miR-29 family. Knockdown of MIAT resulted in increased miR-29 family and decreased COL1A1 and COL3A1 levels, suggesting nicotine-mediated MIAT induction as the underlying mechanism for nicotine-induced collagen deposition. Luciferase reporter assay and RNA immunoprecipitation studies showed an intense physical interaction between MIAT, miR-29 family, and argonaute 2, corroborating the mechanistic link between perinatal nicotine exposure and increased extracellular matrix deposition. Overall, perinatal nicotine exposure resulted in lower miR-29 family levels in offspring heart, while it elevated cardiac MIAT and collagen type I and III levels. These findings provide mechanistic basis for cardiac dysfunction in perinatal nicotine-exposed offspring and offer multiple novel potential therapeutic targets.NEW & NOTEWORTHY Using an established rat model and cultured primary neonatal cardiac fibroblasts, we show that nicotine mediated MIAT induction as the underlying mechanism for the excessive cardiac collagen deposition. These observations provide mechanistic basis for the increased predisposition to cardiac dysfunction following perinatal cigarette/nicotine exposure and offer novel potential therapeutic targets.

Cross-talk between miR-29c and transforming growth factor-β3 is mediated by an epigenetic mechanism in leiomyoma

OBJECTIVE

To determine the expression of miR-29c and its target gene transforming growth factor-β3 (TGF-β3) in leiomyoma and the mechanisms of their reciprocal regulation.

DESIGN

Experimental study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing hysterectomy for leiomyoma.

INTERVENTION(S)

Overexpression and underexpression of miR-29c; blockade of DNA methyltransferase 1 (DNMT1).

MAIN OUTCOME MEASURE(S)

The miR-29c and its target gene TGF-β3 in leiomyoma and the effects of TGF-β3 and blockade of DNMT1 on miR-29c expression.

RESULT(S)

Leiomyoma expressed significantly lower levels of miR-29c, but higher expression of TGF-β3 compared with matched myometrium. The expression of TGF-β3 and miR-29c were independent of race/ethnicity. Using 3' untranslated region luciferase reporter assay we confirmed that TGF-β3 is a direct target of miR-29c in leiomyoma smooth muscle cells (LSMCs). Gain-of-function of miR-29c in LSMCs inhibited the expression of TGF-β3 at protein and messenger RNA levels, whereas loss-of-function of miR-29c had the opposite effect. Treatment of LSMCs with TGF-β3 inhibited the expression of miR-29c, whereas it stimulated DNMT1 expression. Knockdown of DNMT1 through transfection with small interfering RNA significantly decreased the expression of TGF-β3, and induced miR-29c expression. Knockdown of DNMT1 also attenuated the inhibitory effect of TGF-β3 on miR-29c expression. Furthermore, we demonstrated that TGF-β3 increased the methylation level of miR-29c promoter in LSMCs.

CONCLUSION(S)

There is an inverse relationship in the expression of TGF-β3 and miR-29c in leiomyoma. The TGF-β3 is a direct target of miR-29c and inhibits the expression of miR-29c through an epigenetic mechanism. The cross-talk between miR-29c and TGF-β3 provides a feed forward mechanism of fibrosis in leiomyoma.

The Transcription Factor-microRNA Regulatory Network during hESC-chondrogenesis

Human embryonic stem cells (ESCs) offer a promising therapeutic approach for osteoarthritis (OA). The unlimited source of cells capable of differentiating to chondrocytes has potential for repairing damaged cartilage or to generate disease models via gene editing. However their use is limited by the efficiency of chondrogenic differentiation. An improved understanding of the transcriptional and post-transcriptional regulation of chondrogenesis will enable us to improve hESC chondrogenic differentiation protocols. Small RNA-seq and whole transcriptome sequencing was performed on distinct stages of hESC-directed chondrogenesis. This revealed significant changes in the expression of several microRNAs including upregulation of known cartilage associated microRNAs and those transcribed from the Hox complexes, and the downregulation of pluripotency associated microRNAs. Integration of miRomes and transcriptomes generated during hESC-directed chondrogenesis identified key functionally related clusters of co-expressed microRNAs and protein coding genes, associated with pluripotency, primitive streak, limb development and extracellular matrix. Analysis identified regulators of hESC-directed chondrogenesis such as miR-29c-3p with 10 of its established targets identified as co-regulated 'ECM organisation' genes and miR-22-3p which is highly co-expressed with ECM genes and may regulate these genes indirectly by targeting the chondrogenic regulators SP1 and HDAC4. We identified several upregulated transcription factors including HOXA9/A10/D13 involved in limb patterning and RELA, JUN and NFAT5, which have targets enriched with ECM associated genes. We have developed an unbiased approach for integrating transcriptome and miRome using protein-protein interactions, transcription factor regulation and miRNA target interactions and identified key regulatory networks prominent in hESC chondrogenesis.

Prenatal metyrapone treatment modulates neonatal cerebrovascular structure, function, and vulnerability to mild hypoxic-ischemic injury

This study explored the hypothesis that late gestational reduction of corticosteroids transforms the cerebrovasculature and modulates postnatal vulnerability to mild hypoxic-ischemic (HI) injury. Four groups of Sprague-Dawley neonates were studied: 1) Sham-Control, 2) Sham-MET, 3) HI-Control, and 4) HI-MET. Metyrapone (MET), a corticosteroid synthesis inhibitor, was administered via drinking water from gestational day 11 to term. In Shams, MET administration 1) decreased reactivity of the hypothalamic-pituitary-adrenal (HPA) axis to surgical trauma in postnatal day 9 (P9) pups by 37%, 2) promoted cerebrovascular contractile differentiation in middle cerebral arteries (MCAs), 3) decreased compliance ≤46% and increased depolarization-induced calcium mobilization in MCAs by 28%, 4) mildly increased hemispheric cerebral edema by 5%, decreased neuronal degeneration by 66%, and increased astroglial and microglial activation by 10- and 4-fold, respectively, and 5) increased righting reflex times by 29%. Regarding HI, metyrapone-induced fetal transformation 1) diminished reactivity of the HPA axis to HI-induced stress in P9/P10 pups, 2) enhanced HI-induced contractile dedifferentiation in MCAs, 3) lessened the effects of HI on MCA compliance and calcium mobilization, 4) decreased HI-induced neuronal injury but unmasked regional HI-induced depression of microglial activation, and 5) attenuated the negative effects of HI on open-field exploration but enhanced the detrimental effects of HI on negative geotaxis responses by 79%. Overall, corticosteroids during gestation appear essential for normal cerebrovascular development and glial quiescence but induce persistent changes that in neonates manifest beneficially as preservation of postischemic contractile differentiation but detrimentally as worsened ischemic cerebrovascular compliance, increased ischemic neuronal injury, and compromised neurobehavior.

miR-29b Reverses T helper 1 cells/T helper 2 cells Imbalance and Alleviates Airway Eosinophils Recruitment in OVA-Induced Murine Asthma by Targeting Inducible Co-Stimulator

Asthma is a complex chronic disease and the pathogenesis is still not entirely clear. In this study, we aimed to clarify the role and mechanism of miR-29b in the development of asthma. We observed that miR-29b levels were decreased in the lung and spleen of OVA-induced asthmatic mice. Reverse transcription-quantitative polymerase chain reaction and flow cytometry demonstrated that the inducible co-stimulator (ICOS) expression at mRNA and protein levels was elevated in the lung of asthmatic mice, and miR-29b expression in the lung of asthmatic mice was negatively associated with ICOS mRNA levels by Pearson Correlation analysis. Additional, flow cytometry showed that the percentage of CD4+ICOS+ T cells in the lung and spleen was regulated by miR-29b, and dual luciferase reporter assay confirmed ICOS was a target gene of miR-29b. Furthermore, miR-29b overexpression in asthmatic mice was induced with miR-29b agomir by intranasal administration; miR-29b alleviated total inflammatory cell infiltration and CCL24 levels, decreased IL-5 levels in bronchoalveolar lavage fluid and serum, and upregulated IFN-γ expression in serum. This study demonstrates that miR-29b targets ICOS, thereby reverses the imbalance of T helper 1 cells (Th1)/Th2 responses and decreases eosinophils recruitment in the airway, which are key features of allergic airway inflammation. Therefore, miR-29b might be an attractive candidate target for asthma treatment.

The role of microRNAs in the involvement of vascular smooth muscle cells in the development of atherosclerosis

MicroRNAs (miRNAs) are a class of nonprotein-encoding RNAs of ~22 nucleotides in length that bind to or complement each other with a target gene messenger RNA (mRNA) to promote mRNA degradation or inhibit translation of the target mRNA. The protein required [such as Toll-like receptor (TLR) proteins] is controlled at an optimal level. By affecting protein translation, miRNAs have become powerful regulators of biological processes, including development, differentiation, cell proliferation, and apoptosis. MiRNAs are involved in the regulation of proliferation, migration, and apoptosis of vascular smooth muscle cells (VSMCs), thereby affecting the formation of atherosclerosis (AS). In recent years, the role and mechanism of miRNAs involved in AS development in VSMCs have been studied extensively. In the current study, the results and progress in miRNA research are reviewed.

Rab7‑mediated autophagy regulates phenotypic transformation and behavior of smooth muscle cells via the Ras/Raf/MEK/ERK signaling pathway in human aortic dissection

Autophagy regulates the metabolism, survival and function of numerous types of cell, including cells that comprise the cardiovascular system. The dysfunction of autophagy has been demonstrated in atherosclerosis, restenotic lesions and hypertensive vessels. As a member of the Ras GTPase superfamily, Rab7 serves a significant role in the regulation of autophagy. The present study evaluated how Rab7 affects the proliferation and invasion, and phenotypic transformations of aortic dissection (AD) smooth muscle cells (SMCs) via autophagy. Rab7 was overexpressed in AD tissues and the percentage of synthetic human aortic SMCs (HASMCs) was higher in AD tissues compared with NAD tissues. Downregulation of Rab7 decreased cell growth, reduced the number of invasive cells and decreased the percentage cells in the G1 phase. Autophagy of HASMCs was inhibited following Rab7 knockdown. Inhibition of autophagy with 3‑methyladenine or Rab7 knockdown suppressed the phenotypic conversion of contractile to synthetic HASMCs. The action of Rab7 may be mediated by inhibiting the Ras/Raf/mitogen‑activated protein kinase (MAPK) kinase (MEK)/extracellular signal related kinase (ERK) signaling pathway. In conclusion, the results revealed that Rab7‑mediated autophagy regulated the behavior of SMCs and the phenotypic transformations in AD via activation of the Ras/Raf/MEK/ERK signaling pathway. The findings of the present study may improve understanding of the role Rab7 in the molecular etiology of AD and suggests the application of Rab7 as a novel therapeutic target in the treatment of human AD.

Chronic psychological stress impairs germinal center response by repressing miR-155

Germinal centers (GC) are vital to adaptive immunity. BCL6 and miR-155 are implicated in control of GC reaction and lymphomagenesis. FBXO11 causes BCL6 degradation through ubiquitination in B-cell lymphomas. Chronic psychological stress is known to drive immunosuppression. Corticosterone (CORT) is an adrenal hormone expressed in response to stress and can similarly impair immune functions. However, whether GC formation is disrupted by chronic psychological stress and its molecular mechanism remain to be elucidated. To address this issue, we established a GC formation model in vivo, and a GC B cell differentiation model in vitro. Comparing Naive B cells to GC B cells in vivo and in vitro, the differences of BCL6 and FBXO11 mRNA do not match the changes at the protein level and miR-155 levels that were observed. Next we demonstrated that CORT increase, induced by chronic psychological stress, reduced GC response, IgG1 antibody production and miR-155 level in vivo. The effect of chronic psychological stress can be blocked by a glucocorticoid receptor (GR) antagonist. Similarly, impaired GC B cell generation and isotope class switching were observed. Furthermore, we found that miR-155 and BCL6 expression were downregulated, but FBXO11 expression was upregulated in GC B cells treated with CORT in vitro. In addition, we demonstrated that miR-155 directly down-regulated FBXO11 expression by binding to its 3́-untranslated region. The subsequent overexpression of miR-155 significantly blocked the stress-induced impairment of GC response, due to changes in FBXO11 and BCL6 expression, as well as increased apoptosis in B cells both in vivo and in vitro. Our findings suggest perturbation of GC reaction may play a role in chronic psychological stress-induced immunosuppression through a glucocorticoid pathway, and miR-155-mediated post-transcriptional regulation of FBXO11 and BCL6 expression may contribute to the impaired GC response.

Identification of Cardiomyopathy-Associated Circulating miRNA Biomarkers in Muscular Dystrophy Female Carriers Using a Complementary Cardiac Imaging and Plasma Profiling Approach

Background: Different from males with Duchenne/Becker muscular dystrophy (DMD/BMD) in whom overt myopathy is the rule, muscular dystrophy (MD) female carriers are mostly free of skeletal muscle symptoms. However, similar to MD males, these females are also prone to cardiomyopathy. Since circulating microRNAs (miRNAs) have been proposed as diagnostic biomarkers for various cardiovascular diseases, the aim of the current study was to identify specific circulating miRNAs in the plasma of female DMD/BMD carriers that may allow an early and accurate diagnosis of cardiac involvement in these cases.

Methods: Twenty-nine female MD carriers and 24 age-matched healthy female controls were prospectively enrolled. All MD carriers and controls underwent comprehensive cardiovascular magnetic resonance (CMR) studies as well as venous blood sampling on the same day.

Results: An impaired left ventricular (LV) systolic function was detected in 4 (14%) MD carriers while late gadolinium enhancement (LGE) indicative of myocardial fibrosis was present in 13 female patients (45%)—with an exclusively non-ischemic pattern. Among the circulating miRNAs examined, six were significantly up-regulated in MD carriers compared to female controls: miR-206 (103-fold increase, p < 0.0001), miR-222 (41-fold, p < 0.0001), miR-26a (fourfold, p = 0.029), miR-342 (27-fold, p < 0.0001), miR-378a-3p (minimum 3,600-fold; almost undetectable in controls, p = 0.013), miR-378a-5p (64-fold, p < 0.0001); only two miRNAs were substantially down-regulated in MD carriers: miR-144 (p < 0.0001) and miR-29a (p = 0.002) (both undetectable in carriers). A significant down-regulation of the miR-29c (<0.001-fold, p = 0.006) was observed in MD carriers with abnormal CMR findings (comprising functional and/or structural abnormalities) compared to those with normal CMR examinations. Univariable analyses regarding the presence of abnormal CMR findings resulted in four significant variables: LV end-diastolic volume index (EDVi), LV end-systolic volume index (ESVi), an elevated plasma creatine kinase (CK), and decreased serum miR-29c levels. In subsequent multivariable analysis, the only independent predictor for an abnormal CMR among MD carriers was circulating miR-29c (OR 0.99, 95% CI 0.98–0.99, p = 0.037). Moreover, an elevated CK and/or a downregulated miR-29c level (<0.05 × 10^-3) resulted in an improved AUC value of 0.79 (0.62–0.97, p = 0.007) (79, 80 and 80%, sensitivity, specificity and overall accuracy) for the CMR-based diagnosis of cardiomyopathy in MD carriers when compared to using the two parameters individually.

Conclusion: In female MD carriers, down-regulation of circulating miR-29c relates to the presence of functional and/or structural cardiac abnormalities (as detected by CMR) and appears to be a promising novel biomarker—in addition to conventional CK plasma levels—for an early diagnosis of cardiomyopathy.

Fetal Cerebrovascular Maturation: Effects of Hypoxia

The human cerebral vasculature originates in the fourth week of gestation and continues to expand and diversify well into the first few years of postnatal life. A key feature of this growth is smooth muscle differentiation, whereby smooth muscle cells within cerebral arteries transform from migratory to proliferative to synthetic and finally to contractile phenotypes. These phenotypic transformations can be reversed by pathophysiological perturbations such as hypoxia, which causes loss of contractile capacity in immature cerebral arteries. In turn, loss of contractility affects all whole-brain cerebrovascular responses, including those involved in flow-metabolism coupling, vasodilatory responses to acute hypoxia and hypercapnia, cerebral autoregulation, and reactivity to activation of perivascular nerves. Future strategies to minimize cerebral injury following hypoxia-ischemic insults in the immature brain might benefit by targeting treatments to preserve and promote contractile differentiation in the fetal cerebrovasculature. This could potentially be achieved through inhibition of receptor tyrosine kinase-mediated growth factors, such as vascular endothelial growth factor and platelet-derived growth factor, which are mobilized by hypoxic and ischemic injury and which facilitate contractile dedifferentiation. Interruption of the effects of other vascular mitogens, such as endothelin and angiotensin-II, and even some miRNA species, also could be beneficial. Future experimental work that addresses these possibilities offers promise to improve current clinical management of neonates who have suffered and survived hypoxic, ischemic, asphyxic, or inflammatory cerebrovascular insults.

Role of miR-29 in mediating offspring lung phenotype in a rodent model of intrauterine growth restriction

Considerable epidemiological and experimental evidence supports the concept that the adult chronic lung disease (CLD), is due, at least in part, to aberrations in early lung development in response to an abnormal intrauterine environment; however, the underlying molecular mechanisms remain unknown. We used a well-established rat model of maternal undernutrition (MUN) during pregnancy that results in offspring intrauterine growth restriction (IUGR) and adult CLD to test the hypothesis that in response to MUN, excess maternal glucocorticoids (GCs) program offspring lung development to a CLD phenotype by altering microRNA (miR)-29 expression, which is a key miR in regulating extracellular matrix (ECM) deposition during development and injury-repair. At postnatal day 21 and 5 mo, compared with the control offspring lung, MUN offspring lung miR-29 expression was significantly decreased in conjunction with an elevated expression of multiple downstream target ECM proteins [collagen (COL)1A1, COL3A1, COL4A5, and elastin], at both mRNA and protein levels. Importantly, MUN-induced changes in miR-29 and target gene expressions were at least partially blocked in the lungs of offspring of MUN dams treated with metyrapone, a selective GC synthesis inhibitor. Furthermore, dexamethasone treatment of cultured fetal rat lung fibroblasts significantly induced miR-29 expression along with the suppression of target ECM proteins. These data, along with the previously known role of miR-29 in regulating ECM deposition in vascular tissue in the MUN offspring, suggest miR-29 to be a common mechanistic denominator for the vascular and pulmonary phenotypes in the IUGR offspring, providing a novel potential therapeutic target.

The role of miR-29c/B7-H3 axis in children with allergic asthma

Background

MicroRNAs play roles in the pathogenesis of bronchial asthma. However, the mechanism of miR-29c in allergic asthma remains unclear. This study is to elucidate the regulation of Th cell differentiation by miR-29c in mononuclear macrophages.

Methods

A total of 52 children with asthma exacerbation and 26 children as controls were enrolled in the study. CD14⁺ monocytes were isolated from the peripheral blood. Differential expressions of microRNAs were evaluated using microarray analysis and miR-29c expression in monocytes was determined by qRT-PCR. The plasma B7-H3 was determined by ELISA. Transfection studies and luciferase reporter assay were performed to confirm target gene of miR-29c and its function.

Results

Compared to controls, 88 miRNAs in blood monocytes were up-regulated and 41 miRNAs down-regulated including miR-29c in asthma children. Children with asthma exacerbation had significantly lower level of miR-29c and higher level of plasma B7-H3 compared to controls (both P < 0.05). Functional studies based on luciferase reporter assay and immunofluorescence staining suggest that B7-H3 is the direct target of miR-29c and transfection anti-miR-29c into macrophages could enhance ROR-γt and GATA-3 expression in co-cultured CD4⁺ T cells and increase levels of IL-4 and IL-17 in supernatants.

Conclusion

The axis of miR-29c/B7-H3 plays an important role in children with asthma through regulating Th2/Th17 cell differentiation and may provide new targets for treatment of asthma.

Can Hyaluronidase Be an Alternative Postoperative Anti-edema Agent to Dexamethasone? Preliminary Results of an Animal Study

PURPOSE

Recombinant human hyaluronidase (rHuPH20) is widely used as a spreading factor, which enhances the absorption of subcutaneously injected medicines. The anti-inflammatory and anti-edema effects of the enzyme were demonstrated in previous studies. In the present study, the anti-edema effect of rHuPH20 was compared with that of dexamethasone in a traumatic rat paw edema model.

MATERIALS AND METHODS

Twenty-four Sprague-Dawley rats (weight 200 to 450 g) were divided into 3 groups: control (group 1), rHuPH20 (group 2), and dexamethasone (group 3). Traumatic edema was induced in the right hind paws of the rats using Feeney's weight-drop model. After edema induction, 0.4 mL of rHuPH20 (100 U/kg = 0.88 μg/kg dose) and 0.4 mL of dexamethasone (0.5 mg/kg dose) were injected into the right hind paws of the rats in groups 2 and 3. The paw volumes were measured before edema induction and at 3, 6, 12, 24, 48, and 72 hours after induction using a plethysmometer. The Mann-Whitney U test was used for the statistical analyses. Probabilities < .05 were accepted as statistically significant.

RESULTS

The between percentage change in the edema mean values of groups 1 and 3 showed no significant difference at all time points; however, group 2 showed significantly less change in the edema mean values at 3, 6, 12, 24, and 48 hours after edema induction (P < .05) compared with group 1. The change in the edema mean value for group 2 was significantly less than that for group 3 at 3, 6, 12, 24, and 48 hours after edema induction (P < .05).

CONCLUSIONS

Local rHuPH20 injection more effectively reduced the edema that was induced traumatically in rat paws than did dexamethasone. However, further clinical studies are needed regarding the use of rHuPH20 as a postoperative anti-edema agent in place of dexamethasone.

High-Throughput Sequencing of microRNAs in Glucocorticoid Sensitive Paediatric Inflammatory Bowel Disease Patients

The aim of this research was the identification of novel pharmacogenomic biomarkers for better understanding the complex gene regulation mechanisms underpinning glucocorticoid (GC) action in paediatric inflammatory bowel disease (IBD). This goal was achieved by evaluating high-throughput microRNA (miRNA) profiles during GC treatment, integrated with the assessment of expression changes in GC receptor (GR) heterocomplex genes. Furthermore, we tested the hypothesis that differentially expressed miRNAs could be directly regulated by GCs through investigating the presence of GC responsive elements (GREs) in their gene promoters. Ten IBD paediatric patients responding to GCs were enrolled. Peripheral blood was obtained at diagnosis (T0) and after four weeks of steroid treatment (T4). MicroRNA profiles were analyzed using next generation sequencing, and selected significantly differentially expressed miRNAs were validated by quantitative reverse transcription-polymerase chain reaction. In detail, 18 miRNAs were differentially expressed from T0 to T4, 16 of which were upregulated and 2 of which were downregulated. Out of these, three miRNAs (miR-144, miR-142, and miR-96) could putatively recognize the 3’UTR of the GR gene and three miRNAs (miR-363, miR-96, miR-142) contained GREs sequences, thereby potentially enabling direct regulation by the GR. In conclusion, we identified miRNAs differently expressed during GC treatment and miRNAs which could be directly regulated by GCs in blood cells of young IBD patients. These results could represent a first step towards their translation as pharmacogenomic biomarkers.

Next-generation sequencing reveals differentially expressed small noncoding RNAs in uterine leiomyoma

OBJECTIVE

To determine the expression profile of small noncoding RNAs (sncRNAs) in leiomyoma, which has not been investigated to date.

DESIGN

Laboratory-based investigation.

SETTING

Academic center.

PATIENT(S)

Women undergoing hysterectomy for benign indications.

INTERVENTION(S)

Next-generation sequencing and screening of an sncRNA database with confirmatory analysis by quantitative reverse-transcription polymerase chain reaction (qRT-PCR).

MAIN OUTCOME MEASURE(S)

Expression profile of sncRNAs in leiomyoma and matched myometrium.

RESULT(S)

Screening our previously determined RNA sequencing data with the sncRNA database resulted in identification of 15 small nuclear (sn) RNAs, 284 small nucleolar (sno) RNAs, 98 Piwi-interacting (pi) RNAs, 152 transfer (t) RNAs, and 45 ribosomal (r) RNAs, of which 15 snoRNAs, 24 piRNAs, 7 tRNAs, and 6 rRNAs were differentially expressed at a 1.5-fold change cutoff in leiomyoma compared with myometrium. We selected 5 snoRNAs, 4 piRNAs, 1 tRNA, and 1 rRNA that were differentially expressed and confirmed their expression in paired tissues (n = 20) from both phases of the menstrual cycle with the use of qRT-PCR. The results indicated up-regulation of the snoRNAs (SNORD30, SNORD27, SNORA16A, SNORD46, and SNORD56) and down-regulation of the piRNAs (piR-1311, piR-16677, piR-20365, piR-4153), tRNA (TRG-GCC5-1), and rRNA (RNA5SP202) expression in leiomyoma compared with myometrium (P<.05). The pattern of expression of these sncRNAs was similar to RNA sequencing analysis, with no menstrual cycle-dependent differences detected except for SNORD30. Because Argonaute 2 (AGO2) is required for sncRNA-mediated gene silencing, we determined its expression and found greater abundance in leiomyoma.

CONCLUSION(S)

Our results provide the first evidence for the differential expression of additional classes of sncRNAs and AGO2 in leiomyoma, implicating their roles as a gene regulatory mechanism.

Regulation of Cell Cycle Regulatory Proteins by MicroRNAs in Uterine Leiomyoma

The objective of this study was to determine whether miR-93, miR-29c, and miR-200c, which we previously reported to be downregulated in leiomyomas, target cell cycle regulatory proteins that influence cell proliferation. Based on TargetScan algorithm 3 cell cycle regulatory proteins namely, E2F transcription factor 1 (E2F1), Cyclin D1 (CCND1) and CDK2 which were predicted to be targets of these miRNAs were  further analyzed. In 30 hysterectomy specimens, we found the expression of E2F1 and CCND1 messenger RNA (mRNA) was increased in leiomyoma as compared to matched myometrium, with no significant changes in CDK2 mRNA levels. There was a significant increase in the abundance of all 3 proteins in leiomyoma in comparison with matched myometrium. Using luciferase reporter assay, we demonstrated E2F1 and CCND1 are targets of miR-93 and CDK2 is a target of miR-29c and miR-200c. We confirmed these findings through transfection studies in which transfection of primary leiomyoma cells with miR-93 resulted in a significant decrease in the expression of E2F1 and CCND1 mRNA and protein levels, whereas knockdown of miR-93 had the opposite effect. Similarly, overexpression of miR-29c and miR-200c in leiomyoma cells inhibited the expression of CDK2 protein and mRNA, whereas knockdown of this microRNAs (miRNA) had the opposite effect. Transfection of miR-29c, miR-200c, and miR-93 in primary leiomyoma cells resulted in a time-dependent inhibition of cell proliferation and cell motility. These results collectively indicate that the 3 miRNAs known to be downregulated in fibroid tumors are critical in regulation of cell proliferation because of their effects on 3 key cell cycle regulatory proteins, which are overexpressed in uterine leiomyomas.

Post-Transcriptional Control of Tropoelastin in Aortic Smooth Muscle Cells Affects Aortic Dissection Onset

Aortic dissection (AD) is a catastrophic disease with high mortality and morbidity, characterized with fragmentation of elastin and loss of smooth muscle cells. Although AD has been largely attributable to polymorphisms defect in the elastin-coding gene, tropoelastin (TE), other undermined factors also appear to play roles in AD onset. Here, we investigated the effects of post-transcriptional control of TE by microRNAs (miRNAs) on elastin levels in aortic smooth muscle cells (ASMC). We found that miR-144-3p is a miRNA that targets TE mRNA in both human and mouse. Bioinformatics analyses and dual luciferase reporter assay showed that miR-144-3p inhibited protein translation of TE, through binding to the 3'-UTR of the TE mRNA. Interestingly, higher miR-144-3p levels and lower TE were detected in the ASMC obtained from AD patients, compared to those from non-AD controls. In a mouse model for human AD, infusion of adeno-associated viruses (serotype 6) carrying antisense for miR-144-3p (as-miR-144-3p) under CAG promoter significantly reduced the incidence and severity of AD, seemingly through enhancement of TE levels in ASMC. Thus, our data suggest an essential role of miR-144-3p on the pathogenesis of AD.

Hypoxia-inducible factor 1a induces phenotype switch of human aortic vascular smooth muscle cell through PI3K/AKT/AEG-1 signaling

To date, hypoxia-inducible factor 1a (HIF-1a) and astrocyte elevated gene-1 (AEG-1) have been involved in the proliferation, migration and morphological changes of vascular smooth muscle cells. However, the potential relationship of HIF-1a-AEG-1 pathway in human aortic smooth muscle cell (HASMC) has not been reported. In the present study, in-vitro assays were utilized to explore the potential impact of HIF-1a-AEG-1 signaling on HASMC phenotype. Here, we found that HIF-1a expression was up-regulated in the media of thoracic aortic dissection tissues as compared with normal aortic tissues, and was associated with increased apoptotic SMCs and decreased AEG-1 expression. Mechanically, hypoxia promoted the expression of HIF-1a by PI3K-AKT pathway in HASMCs; HIF-1a further suppressed the expressions of AEG-1, a-SMA and SM22a, and promoted osteopontin (OPN) expression. Functionally, HIF-1a inhibited the proliferation and migration of HASMCs. However, si-HIF-1a or Akt inhibitor abrogated HIF-1a-mediated related expressions and biological effects above. In conclusion, HIF-1a induces HASMC phenotype switch, and closely related to PI3K/AKT and AEG-1 signaling, which may provide new avenues for the prevention and treatment of aortic dissection diseases.

A single-nucleotide polymorphism in MMP9 is associated with decreased risk of steroid-induced osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a common hip joint disease, and steroid-induced ONFH accounts for a large number of cases. Here, we examined eight previously-identified single-nucleotide polymorphisms (SNPs) in the MPP2 and MPP9 genes of 285 steroid-induced ONFH patients and 507 healthy controls from northern China to determine whether these SNPs were associated with the risk of developing steroid-induced ONFH. Chi-squared tests and genetic model and haplotype analyses were used to evaluate associations. The rs2274755 SNP in MMP9 was associated with a decreased risk of steroid-induced ONFH in the allele, dominant, and additive models. Additionally, the “CGC” MMP9 haplotype was associated with a 0.69-fold decrease in the risk of steroid-induced ONFH. Although additional, larger population-based studies are needed to confirm these findings, our results reveal for the first time an association between a MMP9 SNP at the rs2274755 locus and a decreased risk of steroid-induced ONFH in a northern Chinese population.

Species-specific regulation of angiogenesis by glucocorticoids reveals contrasting effects on inflammatory and angiogenic pathways

Glucocorticoids are potent inhibitors of angiogenesis in the rodent in vivo and in vitro but the mechanism by which this occurs has not been determined. Administration of glucocorticoids is used to treat a number of conditions in horses but the angiogenic response of equine vessels to glucocorticoids and, therefore, the potential role of glucocorticoids in pathogenesis and treatment of equine disease, is unknown. This study addressed the hypothesis that glucocorticoids would be angiostatic both in equine and murine blood vessels.The mouse aortic ring model of angiogenesis was adapted to assess the effects of cortisol in equine vessels. Vessel rings were cultured under basal conditions or exposed to: foetal bovine serum (FBS; 3%); cortisol (600 nM), cortisol (600nM) plus FBS (3%), cortisol (600nM) plus either the glucocorticoid receptor antagonist RU486 or the mineralocorticoid receptor antagonist spironolactone. In murine aortae cortisol inhibited and FBS stimulated new vessel growth. In contrast, in equine blood vessels FBS alone had no effect but cortisol alone, or in combination with FBS, dramatically increased new vessel growth compared with controls. This effect was blocked by glucocorticoid receptor antagonism but not by mineralocorticoid antagonism. The transcriptomes of murine and equine angiogenesis demonstrated cortisol-induced down-regulation of inflammatory pathways in both species but up-regulation of pro-angiogenic pathways selectively in the horse. Genes up-regulated in the horse and down-regulated in mice were associated with the extracellular matrix. These data call into question our understanding of glucocorticoids as angiostatic in every species and may be of clinical relevance in the horse.

Upregulated miR-29c suppresses silica-induced lung fibrosis through the Wnt/β-catenin pathway in mice

Silicosis is an irreversible lung disease resulting from long-term inhalation of occupational dust containing silicon dioxide. However, the pathogenesis of silicosis has not been clearly understood yet. Accumulating evidence suggests that miR-29 may have a significant anti-fibrotic capacity, meanwhile it may relate to Wnt/β-catenin pathway. The purpose of this study was to discuss the role of miR-29 in the progression of silicosis. A lentiviral vector was constructed, named Lv-miR-29c, which was overexpressing miR-29c. In vivo, intratracheal treatment with Lv-miR-29c significantly increased expression of miR-29c, and reduced expression of β-catenin, matrix metalloproteinase (MMP)-2, and MMP-9 in the lung and levels of transforming growth factor-beta 1 (TGF-β1) and interleukin-6 (IL-6) in bronchoalveolar lavage fluid, and notably attenuated pulmonary fibrosis as evidenced by hydroxyproline content in silica-administered mice. These results indicated that miR-29c inhibited the development of silica-induced lung fibrosis. Thus, miR-29c may be a candidate target for silicosis treatment via its regulation of the Wnt/β-catenin pathway.

Vascular Smooth Muscle Cells and Arterial Stiffening: Relevance in Development, Aging, and Disease

The cushioning function of large arteries encompasses distension during systole and recoil during diastole which transforms pulsatile flow into a steady flow in the microcirculation. Arterial stiffness, the inverse of distensibility, has been implicated in various etiologies of chronic common and monogenic cardiovascular diseases and is a major cause of morbidity and mortality globally. The first components that contribute to arterial stiffening are extracellular matrix (ECM) proteins that support the mechanical load, while the second important components are vascular smooth muscle cells (VSMCs), which not only regulate actomyosin interactions for contraction but mediate also mechanotransduction in cell-ECM homeostasis. Eventually, VSMC plasticity and signaling in both conductance and resistance arteries are highly relevant to the physiology of normal and early vascular aging. This review summarizes current concepts of central pressure and tensile pulsatile circumferential stress as key mechanical determinants of arterial wall remodeling, cell-ECM interactions depending mainly on the architecture of cytoskeletal proteins and focal adhesion, the large/small arteries cross-talk that gives rise to target organ damage, and inflammatory pathways leading to calcification or atherosclerosis. We further speculate on the contribution of cellular stiffness along the arterial tree to vascular wall stiffness. In addition, this review provides the latest advances in the identification of gene variants affecting arterial stiffening. Now that important hemodynamic and molecular mechanisms of arterial stiffness have been elucidated, and the complex interplay between ECM, cells, and sensors identified, further research should study their potential to halt or to reverse the development of arterial stiffness.

Pentablock copolymer dexamethasone nanoformulations elevate MYOC: in vitro liberation, activity and safety in human trabecular meshwork cells

AIM

The aim of this study is to examine the elevation of MYOC in long-term treatment of human trabecular meshwork (HTM) cells using dexamethasone (DEX) encapsulated pentablock (PB) copolymer-based nanoparticles (NPs) (DEX-PB-NPs).

MATERIALS & METHODS

PB copolymers and DEX-PB-NPs were synthesized and characterized using nuclear magnetic resonance, gel permeation chromatography, and X-ray diffraction analyses. MYOC levels secreted from HTM cells were measured by western blot (WB) analysis.

RESULTS

DEX-PB-NPs were formulated in the size range of 109 ± 3.77 nm (n = 3). A long term DEX release from the NPs was observed over three months. Cell viability and cytotoxicity were not affected up to 12 weeks of treatment with PB-copolymer or DEX-PB-NPs. WB data from five HTM cell strains showed that MYOC levels increased by 5.2 ± 1.3, 7.4 ± 4.3, and 2.8 ± 1.1-fold in the presence of DEX-PB-NPs compared with 9.2 ± 3.8, 2.2 ± 0.5, and 1.5 ± 0.3-fold at 4, 8 and 12 weeks in control-DEX treatment group, respectively (n = 5). Based on the decline in MYOC levels after withdrawal of DEX from control wells, DEX-PB-NPs released the DEX for at least 10 weeks.

CONCLUSION

The treatment of HTM cells using DEX-PB-NPs were analyzed in this study. The in vitro cell-based system developed here is a valuable tool for determining the safety and effects of steroids released from polymeric NPs.

The Role of c-SKI in Regulation of TGFβ-Induced Human Cardiac Fibroblast Proliferation and ECM Protein Expression

Cardiac fibrosis is characterized by over-deposition of extracellular matrix (ECM) proteins and over-proliferation of cardiac fibroblast, and contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. Transforming growth factor β 1 (TGFβ1) is as an essential inducing factor of cardiac fibrosis. C-Ski protein has been identified as an inhibitory regulator of TGFβ signaling. In the present study, we revealed the repressive effect of c-Ski on TGFβ1-induced human cardiac fibroblast (HCFB) proliferation and ECM protein increase (Collagen I and α-SMA). Moreover, miR-155 and miR-17 could inhibit SKI mRNA expression by direct binding to the 3'UTR of SKI, so as to reduce c-Ski protein level. Either miR-155 inhibition or miR-17 inhibition could reverse TGFβ1-induced HCFB proliferation and ECM protein increase. Taken together, we provided a potential therapy to treat cardiac fibrosis by inhibiting miR-155/miR-17 so as to restore the repressive effect of c-Ski on TGFβ1 signaling. J. Cell. Biochem. 118: 1911-1920, 2017. © 2017 Wiley Periodicals, Inc.

Tranilast Inhibits Genes Functionally Involved in Cell Proliferation, Fibrosis, and Epigenetic Regulation and Epigenetically Induces miR-29c Expression in Leiomyoma Cells

Tranilast (N-3,4-dimethoxycinnamoyl anthranilic acid) is an antiallergic agent with inhibitory effects on cell proliferation and extracellular matrix production. Here we assess the effect of tranilast on the expression of miR-29c and genes functionally involved in cell proliferation, fibrosis, and epigenetic regulation in isolated leiomyoma smooth muscle cells (LSMC). Tranilast significantly inhibited the rate of LSMC proliferation, which was associated with downregulation of cell cycle progression genes cyclin D1 (CCND1) and cyclin-dependent kinase 2 (CDK2) expression at messenger RNA and protein levels ( P < .05). Tranilast also suppressed the expression of collagen type I (COL1), collagen type III alpha 1 chain (COL3A1), the profibrotic cytokine, transforming growth factor β-3 (TGF-β3), DNA (cytosine-5)-methyltransferase 1 (DNMT1), and enhancer of zeste homolog 2 (EZH2), which regulate epigenetic status of gene promoters ( P < .05). Tranilast also significantly induced the expression of cellular and secreted miR-29c through downregulation of methylation status of miR-29c promoter ( P < .05). In addition, tranilast suppressed the activity of luciferase reporter containing 3'UTR of COL3A1 and CDK2, which are downstream targets of miR-29c ( P < .05). Knockdown of miR-29c expression attenuated the inhibitory effects of tranilast on COL3A1 and CDK2 protein expression ( P < .05). Collectively, these findings suggest that tranilast could have therapeutic potential as an inhibitory agent for leiomyoma growth and its associated symptoms.

Differential response and withdrawal profile of glucocorticoid-treated human trabecular meshwork cells

The goal of the study was to examine secreted protein response and withdrawal profiles from cultured human trabecular meshwork (HTM) cells following short- and long-term glucocorticoid treatment. Primary cultures of five human HTM cell strains isolated from 5 different individual donor eyes were tested. Confluent HTM cells were differentiated in culture media containing 1% FBS for at least one week, and then treated with Dexamethasone (Dex, 100 nM) 3 times/week for 1 or 4 weeks. Cell culture supernatants were collected 3 times per week for 8 weeks. Secretion profiles of myocilin (MYOC), matrix metalloproteinase-2 (MMP2) and fibronectin (FN) were determined by Western blot analysis and MMP2 activity by zymography. Dex treatment reduced MMP2 expression and activity, returning to normal levels shortly after Dex withdrawal in 5 HTM cell strains. All five cell strains significantly upregulated MYOC in response to Dex treatment by an average of 17-fold, but recovery to basal levels after Dex withdrawal took vastly different periods of time depending on cell strain and treatment duration. Dex treatment significantly increased FN secretion in all strains but one, which decreased FN secretion in the presence of Dex. Interestingly, secretion of FN and MYOC negatively correlated during a 4 week recovery period following 4 weeks of Dex treatment. Taken together, the time course and magnitude of response and recovery for three different secreted, extracellular matrix-associated proteins varied greatly between HTM cell strains, which may underlie susceptibility to glucocorticoid-induced ocular hypertension.

MicroRNAs 29b and 181a down-regulate the expression of the norepinephrine transporter and glucocorticoid receptors in PC12 cells

MicroRNAs are short non-coding RNAs that provide global regulation of gene expression at the post-transcriptional level. Such regulation has been found to play a role in stress-induced epigenetic responses in the brain. The norepinephrine transporter (NET) and glucocorticoid receptors are closely related to the homeostatic integration and regulation after stress. Our previous studies demonstrated that NET mRNA and protein levels in rats are regulated by chronic stress and by administration of corticosterone, which is mediated through glucocorticoid receptors. Whether miRNAs are intermediaries in the regulation of these proteins remains to be elucidated. This study was undertaken to determine possible regulatory effects of miRNAs on the expression of NET and glucocorticoid receptors in the noradrenergic neuronal cell line. Using computational target prediction, we identified several candidate miRNAs potentially targeting NET and glucocorticoid receptors. Western blot results showed that over-expression of miR-181a and miR-29b significantly repressed protein levels of NET, which is accompanied by a reduced [³ H] norepinephrine uptake, and glucocorticoid receptors in PC12 cells. Luciferase reporter assays verified that both miR-181a and miR-29b bind the 3'UTR of mRNA of NET and glucocorticoid receptors. Furthermore, exposure of PC12 cells to corticosterone markedly reduced the endogenous levels of miR-29b, which was not reversed by the application of glucocorticoid receptor antagonist mifepristone. These observations indicate that miR-181a and miR-29b can function as the negative regulators of NET and glucocorticoid receptor translation in vitro. This regulatory effect may be related to stress-induced up-regulation of the noradrenergic phenotype, a phenomenon observed in stress models and depressive patients. This study demonstrated that miR-29b and miR-181a, two short non-coding RNAs that provide global regulation of gene expression, markedly repressed protein levels of norepinephrine (NE) transporter and glucocorticoid receptor (GR), as well as NE uptake by binding the 3'UTR of their mRNAs in PC12 cells. Also, exposure of cells to corticosterone significantly reduced miR-29b levels through a GR-independent way.

Mechanisms underlying aberrant expression of miR-29c in uterine leiomyoma

OBJECTIVE

To determine the expression of miR-29c and its target genes in leiomyoma and the role of NF-κB, specific protein 1 (SP1), and DNA methylation in its regulation.

DESIGN

Experimental study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing hysterectomy for leiomyoma.

INTERVENTION(S)

Over- and underexpression of miR-29c; blockade of transcription factors.

MAIN OUTCOME MEASURE(S)

MiR-29c and its target gene levels in leiomyoma and the effects of blockade of transcription factors on miR-29c expression.

RESULT(S)

Leiomyoma as compared with myometrium expressed significantly lower levels of miR-29c, with an inverse relationship with expression of its targets, COL3A1 and DNMT3A. Gain of function of miR-29c inhibited the expression of COL3A1 and DNMT3A at protein and mRNA levels, secreted COL3A1, and rate of cell proliferation. Loss of function of miR-29c had the opposite effect. E2, P, and their combination inhibited miR-29c in leiomyoma smooth muscle cells (LSMC). Phosphorylated NF-κB (p65) and SP1 protein expression were significantly increased in leiomyoma. SiRNA knockdown of SP1 and DNMT3A or their specific inhibitors significantly increased the expression of miR-29c, accompanied by the inhibition of cellular and secreted COL3A1 in siRNA-treated cells. Knockdown of p65 also induced miR-29c expression but had no effect on COL3A1 expression.

CONCLUSION(S)

MiR-29c expression is suppressed in leiomyoma, resulting in an increase in expression of its targets COL3A1 and DNMT3A. The suppression of miR-29c in LSMC is primarily mediated by SP1, NF-κB signaling, and epigenetic modification. Collectively, these results indicate a significant role for miR-29c in leiomyoma pathogenesis.