Mechanical stretch up-regulates microRNA-26a and induces human airway smooth muscle hypertrophy by suppressing glycogen synthase kinase-3β

Three-Dimensional Mechanical Microenvironment Rescued the Decline of Osteogenic Differentiation of Old Human Jaw Bone Marrow Mesenchymal Stem Cells

Resorption and atrophy of the alveolar bone, as two consequences of osteoporosis that remarkably complicate the orthodontic and prosthodontic treatments, contribute to the differentiated biological features and force-induced response of jaw bone marrow-derived mesenchymal stem cells (JBMSCs) in elderly patients. We isolated and cultured JBMSCs from adolescent and adult patients and then simulated the loading of orthodontic tension stress by constructing an in vitro three-dimensional (3D) stress loading model. The decline in osteogenic differentiation of aged JBMSCs was reversed by tensile stress stimulation. It is interesting to note that tension stimulation had a stronger effect on the osteogenic differentiation of elderly JBMSCs compared to the young ones, indicating a possible mechanism of aging rescue. High-throughput sequencing of microRNA (miRNAs) was subsequently performed before and after tension stimulation in all JBMSCs, followed by the comprehensive comparison of mechanically responsive miRNAs in the 3D strain microenvironment. The results suggested a significant reduction in the expression of miR-210-3p and miR-214-3p triggered by the 3D strain microenvironment in old-JBMSCs. Bioinformatic analysis indicated that both miRNAs participate in the regulation of critical pathways of aging and cellular senescence. Taken together, this study demonstrated that the 3D strain microenvironment efficiently rescued the cellular senescence of old-JBMSCs via modulating specific miRNAs, which provides a novel strategy for coordinating periodontal bone loss and regeneration of the elderly.

Role of mechanoregulation in mast cell-mediated immune inflammation of the smooth muscle in the pathophysiology of esophageal motility disorders

Major esophageal disorders involve obstructive transport of bolus to the stomach, causing symptoms of dysphagia and impaired clearing of the refluxed gastric contents. These may occur due to mechanical constriction of the esophageal lumen or loss of relaxation associated with deglutitive inhibition, as in achalasia-like disorders. Recently, immune inflammation has been identified as an important cause of esophageal strictures and the loss of inhibitory neurotransmission. These disorders are also associated with smooth muscle hypertrophy and hypercontractility, whose cause is unknown. This review investigated immune inflammation in the causation of smooth muscle changes in obstructive esophageal bolus transport. Findings suggest that smooth muscle hypertrophy occurs above the obstruction and is due to mechanical stress on the smooth muscles. The mechanostressed smooth muscles release cytokines and other molecules that may recruit and microlocalize mast cells to smooth muscle bundles, so that their products may have a close bidirectional effect on each other. Acting in a paracrine fashion, the inflammatory cytokines induce genetic and epigenetic changes in the smooth muscles, leading to smooth muscle hypercontractility, hypertrophy, and impaired relaxation. These changes may worsen difficulty in the esophageal transport. Immune processes differ in the first phase of obstructive bolus transport, and the second phase of muscle hypertrophy and hypercontractility. Moreover, changes in the type of mechanical stress may change immune response and effect on smooth muscles. Understanding immune signaling in causes of obstructive bolus transport, type of mechanical stress, and associated smooth muscle changes may help pathophysiology-based prevention and targeted treatment of esophageal motility disorders.NEW & NOTEWORTHY Esophageal disorders such as esophageal stricture or achalasia, and diffuse esophageal spasm are associated with smooth muscle hypertrophy and hypercontractility, above the obstruction, yet the cause of such changes is unknown. This review suggests that smooth muscle obstructive disorders may cause mechanical stress on smooth muscle, which then secretes chemicals that recruit, microlocalize, and activate mast cells to initiate immune inflammation, producing functional and structural changes in smooth muscles. Understanding the immune signaling in these changes may help pathophysiology-based prevention and targeted treatment of esophageal motility disorders.

Challenges and promise of targeting miRNA in rheumatic diseases: a computational approach to identify miRNA association with cell types, cytokines, and disease mechanisms

MicroRNAs (miRNAs) are small non-coding RNAs that alter the expression of target genes at the post-transcriptional level, influencing diverse outcomes in metabolism, cell differentiation, proliferation, cell survival, and cell death. Dysregulated miRNA expression is implicated in various rheumatic conditions, including ankylosing spondylitis (AS), gout, juvenile idiopathic arthritis (JIA), osteoarthritis (OA), psoriatic arthritis, rheumatoid arthritis (RA), Sjogren's syndrome, systemic lupus erythematosus (SLE) and systemic sclerosis. For this review, we used an open-source programming language- PowerShell, to scan the massive number of existing primary research publications on PubMed on miRNAs in these nine diseases to identify and count unique co-occurrences of individual miRNAs and the disease name. These counts were used to rank the top seven most relevant immuno-miRs based on their research volume in each rheumatic disease. Individual miRNAs were also screened for publication with the names of immune cells, cytokines, and pathological processes involved in rheumatic diseases. These occurrences were tabulated into matrices to identify hotspots for research relevance. Based on this information, we summarize the basic and clinical findings for the top three miRNAs - miR-146, miR-155, and miR-21 - whose relevance spans across multiple rheumatic diseases. Furthermore, we highlight some unique miRNAs for each disease and why some rheumatic conditions lack research in this emerging epigenetics field. With the overwhelming number of publications on miRNAs in rheumatic diseases, this review serves as a 'relevance finder' to guide researchers in selecting miRNAs based on the compiled existing knowledge of their involvement in disease pathogenesis. This approach applies to other disease contexts with the end goal of developing miRNA-based therapeutics.

MicroRNAs (miRNAs) role in hypertension: pathogenesis and promising therapeutics

Background

MicroRNAs (miRNAs) are small, non-coding RNA molecules that play a crucial role in regulating various cellular processes, including cell proliferation, differentiation, apoptosis, and disease development. Recent studies have highlighted the importance of miRNAs in the development and progression of essential hypertension, a common form of high blood pressure that affects millions of individuals worldwide. The molecular mechanisms by which miRNAs regulate hypertension are complex and multifaceted. MiRNAs target the 3' untranslated regions of mRNA molecules, thereby regulating the synthesis of specific proteins involved in cardiovascular function. For instance, miRNAs are known to regulate the expression of genes involved in blood vessel tone, cardiac function, and inflammation. The growing body of research on miRNAs in hypertension has highlighted their potential as therapeutic targets for managing this condition. Studies have shown that miRNA-based therapies can modulate the expression of key genes involved in hypertension, leading to improvements in blood pressure and cardiovascular function. However, more research is needed to fully understand the mechanisms of miRNA-mediated hypertension and to develop effective therapeutic strategies.

Conclusions

In summary, this review highlights the current understanding of the role of miRNAs in essential hypertension, including their molecular mechanisms and potential therapeutic applications. Further research is needed to fully understand the impact of miRNAs on hypertension and to develop new treatments for this common and debilitating condition.

Reappraisal of the Concept of Accelerated Aging in Neurodegeneration and Beyond

BACKGROUND

Genetic and epigenetic changes, oxidative stress and inflammation influence the rate of aging, which diseases, lifestyle and environmental factors can further accelerate. In accelerated aging (AA), the biological age exceeds the chronological age.

OBJECTIVE

The objective of this study is to reappraise the AA concept critically, considering its weaknesses and limitations.

METHODS

We reviewed more than 300 recent articles dealing with the physiology of brain aging and neurodegeneration pathophysiology.

RESULTS

(1) Application of the AA concept to individual organs outside the brain is challenging as organs of different systems age at different rates. (2) There is a need to consider the deceleration of aging due to the potential use of the individual structure-functional reserves. The latter can be restored by pharmacological and/or cognitive therapy, environment, etc. (3) The AA concept lacks both standardised terminology and methodology. (4) Changes in specific molecular biomarkers (MBM) reflect aging-related processes; however, numerous MBM candidates should be validated to consolidate the AA theory. (5) The exact nature of many potential causal factors, biological outcomes and interactions between the former and the latter remain largely unclear.

CONCLUSIONS

Although AA is commonly recognised as a perspective theory, it still suffers from a number of gaps and limitations that assume the necessity for an updated AA concept.

Noncoding RNAs in asthmatic airway smooth muscle cells

Asthma is a complex and heterogeneous airway disease caused by genetic, environmental and epigenetic factors treated with hormones and biologics. Irreversible pathological changes to airway smooth muscle cells (ASMCs) such as hyperplasia and hypertrophy can occur in asthmatic patients. Determining the mechanisms responsible is vital for preventing such changes. In recent years, noncoding RNAs (ncRNAs), especially microRNAs, long noncoding RNAs and circular RNAs, have been found to be associated with abnormalities of the ASMCs. This review highlights recent ncRNA research into ASMC pathologies. We present a schematic that illustrates the role of ncRNAs in pathophysiological changes to ASMCs that may be useful in future research in diagnostic and treatment strategies for patients with asthma.

Mechanical Ventilation-Related High Stretch Mainly Induces Endoplasmic Reticulum Stress and Thus Mediates Inflammation Response in Cultured Human Primary Airway Smooth Muscle Cells

Ventilator-induced lung injury (VILI) occurs in mechanically ventilated patients of respiratory disease and is typically characterized by airway inflammation. However, recent studies increasingly indicate that a major cause of VILI may be the excessive mechanical loading such as high stretch (>10% strain) on airway smooth muscle cells (ASMCs) due to mechanical ventilation (MV). Although ASMCs are the primary mechanosensitive cells in airways and contribute to various airway inflammation diseases, it is still unclear how they respond to high stretch and what mediates such a response. Therefore, we used whole genome-wide mRNA-sequencing (mRNA-Seq), bioinformatics, and functional identification to systematically analyze the mRNA expression profiles and signaling pathway enrichment of cultured human ASMCs exposed to high stretch (13% strain), aiming to screen the susceptible signaling pathway through which cells respond to high stretch. The data revealed that in response to high stretch, 111 mRNAs with count ≥100 in ASMCs were significantly differentially expressed (defined as DE-mRNAs). These DE-mRNAs are mainly enriched in endoplasmic reticulum (ER) stress-related signaling pathways. ER stress inhibitor (TUDCA) abolished high-stretch-enhanced mRNA expression of genes associated with ER stress, downstream inflammation signaling, and major inflammatory cytokines. These results demonstrate in a data-driven approach that in ASMCs, high stretch mainly induced ER stress and activated ER stress-related signaling and downstream inflammation response. Therefore, it suggests that ER stress and related signaling pathways in ASMCs may be potential targets for timely diagnosis and intervention of MV-related pulmonary airway diseases such as VILI.

Life Course of Asthma

Asthma is a heterogeneous chronic airway disease that can vary over a lifetime. Although broad categories of asthma by severity and type have been constructed, there remains a tremendous opportunity to discover an approach to managing asthma with additional factors in mind. Many in the field have suggested and are pursuing a novel paradigm shift in how asthma might be better managed, considering the life course of exposures, management priorities, and predicted trajectory of lung function growth. This approach will require a more holistic view of prenatal, postnatal, adolescence, hormonal and gender aspects, and the aging process. In addition, the environment, externally and internally, including in one's genetic code and epigenetic changes, are factors that affect how asthma progresses or becomes more stable in individuals. This chapter focuses on the various influences that may, to differing degrees, affect people with asthma, which can develop at any time in their lives. Shifting the paradigm of thought and strategies for care and advocating for public policies and health delivery that focus on this philosophy is paramount to advance asthma care for all.

Unraveling the Mechanobiology Underlying Traumatic Brain Injury with Advanced Technologies and Biomaterials

Traumatic brain injury (TBI) is a worldwide health and socioeconomic problem, associated with prolonged and complex neurological aftermaths, including a variety of functional deficits and neurodegenerative disorders. Research on the long-term effects has highlighted that TBI shall be regarded as a chronic health condition. The initiation and exacerbation of TBI involve a series of mechanical stimulations and perturbations, accompanied by mechanotransduction events within the brain tissues. Mechanobiology thus offers a unique perspective and likely promising approach to unravel the underlying molecular and biochemical mechanisms leading to neural cells dysfunction after TBI, which may contribute to the discovery of novel targets for future clinical treatment. This article investigates TBI and the subsequent brain dysfunction from a lens of neuromechanobiology. Following an introduction, the mechanobiological insights are examined into the molecular pathology of TBI, and then an overview is given of the latest research technologies to explore neuromechanobiology, with particular focus on microfluidics and biomaterials. Challenges and prospects in the current field are also discussed. Through this article, it is hoped that extensive technical innovation in biomedical devices and materials can be encouraged to advance the field of neuromechanobiology, paving potential ways for the research and rehabilitation of neurotrauma and neurological diseases.

Dietary dimethylglycine sodium salt supplementation alleviates redox status imbalance and intestinal dysfunction in weaned piglets with intrauterine growth restriction

There are few studies on the mechanism of redox status imbalance and intestinal dysfunction in intrauterine growth restricted (IUGR) newborn piglets. Here, we investigated the mechanism of jejunum dysfunction in weaned piglets with IUGR and the mechanism through which dimethylglycine sodium salt (DMG-Na) supplementation improving the imbalance of their redox status. In this work, a total of 10 normal birth weight (NBW) newborn piglets and 20 IUGR newborn piglets were obtained. After weaning at 21 d, they were assigned to 3 groups (n = 10/group): NBW weaned piglets fed standard basal diets (NBWC); one IUGR weaned piglets fed standard basal diets (IUGRC); another IUGR weaned piglets from the same litter fed standard basal diets plus 0.1% DMG-Na (IUGRD). The piglets in these 3 groups were sacrificed at 49 d of age, and the blood and jejunum samples were collected immediately. The growth performance values in the IUGRC group were lower (P < 0.05) than those in the NBWC group. Jejunum histomorphological parameters, inflammatory cytokines, and digestive enzyme activity as well as serum immunoglobulin were lower (P < 0.05) in the IUGRC group than those in the NBWC group. Compared with these in the NBWC group, the redox status of serum, jejunum, and mitochondria and the expression levels of jejunum redox status-related, cell adhesion-related, and mitochondrial function-related genes and proteins were suppressed in the IUGRC group (P < 0.05). However, compared with those in the IUGRC group, the growth performance values, jejunum histomorphological parameters, inflammatory cytokines, digestive enzyme activity, serum immunoglobulin, redox status of serum, jejunum, and mitochondria, and the expression levels of jejunum redox status-related, cell adhesion-related, and mitochondrial function-related genes and proteins were improved (P < 0.05) in the IUGRD group. In conclusion, dietary DMG-Na supplementation alleviates redox status imbalance and intestinal dysfunction in IUGR weaned piglets mainly by activating the sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptorγcoactivator-1α (PGC1α) pathway, thereby improving their unfavorable body state.

Epigenetic regulation of immune function in asthma

Asthma is a common complex respiratory disease characterized by chronic airway inflammation and partially reversible airflow obstruction resulting from genetic and environmental determinants. Because epigenetic marks influence gene expression and can be modified by both environmental exposures and genetic variation, they are increasingly recognized as relevant to the pathogenesis of asthma and may be a key link between environmental exposures and asthma susceptibility. Unlike changes to DNA sequence, epigenetic signatures are dynamic and reversible, creating an opportunity for not only therapeutic targets but may serve as biomarkers to follow disease course and identify molecular subtypes in heterogeneous diseases such as asthma. In this review, we will examine the relationship between asthma and 3 key epigenetic processes that modify gene expression: DNA methylation, modification of histone tails, and noncoding RNAs. In addition to presenting a comprehensive assessment of the existing epigenetic studies focusing on immune regulation in asthma, we will discuss future directions for epigenetic investigation in allergic airway disease.

Formation of Blood Neutrophil Extracellular Traps Increases the Mastitis Risk of Dairy Cows During the Transition Period

The current study was conducted to analyze the functions of blood neutrophils in transition cows and their association with postpartum mastitis risk as indicated by somatic cell counts (SCCs) in milk. Seventy-six healthy Holstein dairy cows were monitored from Week 4 prepartum to Week 4 postpartum. Five dairy cows with low SCCs (38 ± 6.0 × 10³/mL) and five with high SCCs (3,753 ± 570.0 × 10³/mL) were selected based on milk SCCs during the first three weeks of lactation. At Week 1 pre- and postpartum, serum samples were obtained from each cow to measure neutrophil extracellular trap (NET)-related variables, and blood neutrophils were collected for transcriptome analysis by RNA sequencing. The serum concentration of NETs was significantly higher (P < 0.05) in cows with high SCCs than in cows with low SCCs (36.5 ± 2.92 vs. 18.4 ± 1.73 ng/mL). The transcriptomic analysis revealed that the transcriptome differences in neutrophils between high- and low-SCC cows were mainly in cell cycle-related pathways (42.6%), including the cell cycle, DNA damage, and chromosomal conformation, at Week 1 prepartum. The hub genes of these pathways were mainly involved in both the cell cycle and NETosis. These results indicated that the formation of NETs in the blood of transition dairy cows was different between cows with low and high SCCs, which may be used as a potential indicator for the prognosis of postpartum mastitis risk and management strategies of perinatal dairy cows.

MicroRNAs in the pathophysiology of Alzheimer's disease and Parkinson's disease: an overview

Neurodegenerative diseases are characterized by a progressive loss of neurons of the central nervous system (CNS) and serve as a major cause of morbidity, mortality and functional dependence especially among the elderly. Despite extensive research and development efforts, the success rate of clinical pipelines has been very limited. However, microRNAs (miRs) have been proved to be of crucial importance in regulating intracellular pathways for various pathologic conditions including those of a neurodegenerative nature. There is ample evidence of altered levels of various miRs in clinical samples of Alzheimer's disease and Parkinson's disease patients with potentially major clinical implications. In the current review, we aim to summarize the relevant literature on the role of miRs in the pathophysiology of Alzheimer's disease (AD) and Parkinson's disease (PD) as the two globally predominant neurodegenerative conditions.

Emerging Roles of Non-Coding RNAs in Childhood Asthma

Asthma is a chronic airway inflammatory disease in children characterized by airway inflammation, airway hyperresponsiveness and airway remodeling. Childhood asthma is usually associated with allergy and atopy, unlike adult asthma, which is commonly associated with obesity, smoking, etc. The pathogenesis and diagnosis of childhood asthma also remains more challenging than adult asthma, such as many diseases showing similar symptoms may coexist and be confused with asthma. In terms of the treatment, although most childhood asthma can potentially be self-managed and controlled with drugs, approximately 5-10% of children suffer from severe uncontrolled asthma, which carries significant health and socioeconomic burdens. Therefore, it is necessary to explore the pathogenesis of childhood asthma from a new perspective. Studies have revealed that non-coding RNAs (ncRNAs) are involved in the regulation of respiratory diseases. In addition, altered expression of ncRNAs in blood, and in condensate of sputum or exhalation affects the progression of asthma via regulating immune response. In this review, we outline the regulation and pathogenesis of asthma and summarize the role of ncRNAs in childhood asthma. We also hold promise that ncRNAs may be used for the development of biomarkers and support a new therapeutic strategy for childhood asthma.

Emerging Advances of Non-coding RNAs and Competitive Endogenous RNA Regulatory Networks in Asthma

Asthma is a chronic inflammatory disease characterized by airway remodeling and bronchial hyperresponsiveness. A variety of effector cells and cytokines jointly stimulate the occurrence of inflammatory response in asthma. Although the pathogenesis of asthma is not entirely clear, the possible roles of non-coding RNAs (ncRNAs) have been recently demonstrated. NcRNAs are non-protein-coding RNA molecules, such as circular RNAs (circRNAs), long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), which are involved in the regulation of a variety of biological processes. Mounting studies have shown that ncRNAs play pivotal roles in the occurrence and progression of asthma via competing endogenous RNA (ceRNA) regulatory networks. However, the specific mechanism and clinical application of ncRNAs and ceRNA regulatory networks in asthma have not been fully elucidated, which are worthy of further investigation. This paper comprehensively summarized the current progress on the roles of miRNAs, lncRNAs, circRNAs, and ceRNA regulatory networks in asthma, which can provide a better understanding for the disease pathogenesis and is helpful for identifying novel biomarkers for asthma.

Silencing of miR-10b-5p alleviates the mechanical stretch-induced proliferation of HASMCs

MicroRNAs (miRNAs) are important mediators to human airway smooth muscle cells (HASMCs) phenotype remodeling and airway diseases. MicroRNA-10b-5p (miR-10b-5p) has been extensively studied in different fields. This study set out to probe into the effect of miR-10b-5p in cyclic mechanical stretch-induced apoptosis in HASMCs. The results showed that after 15 % deformation, 0.5 s stretching and 0.5 s cyclic mechanical stretching relaxation (0.5 Hz) occurred to HASMCs, miR-10b-5p showed up-regulation without inducing significant apoptosis. Moreover, the mRNA and protein expressions of FLT1 were reduced. Then, dual-luciferase reporter assay verified that FLT1 was targeted by miR-10b-5p, and miR-10b-5p silencing increased FLT1 expression, leading to a prolonged arrest of stretch-treated HASMCs at the G1/S stage, and increased cell apoptosis compared with control group. Furthermore, the activity of Caspase-3 was reinforced, and the ratio of Bcl-2 to Bax was markedly reduced after miR-10b-5p silencing. The current study proved that expression levels of p-PI3K and p-Akt in stretch-treated HASMCs of the inhibition group were significantly inhibited in comparison to those of the controls. The effects of miR-10b-5p overexpression are opposite to that of inhibition of miR-10b-5p in stretched HASMCs. In conclusion, this study showed that miR-10b-5p silencing could weaken the hypertrophy of HASMCs. MiR-10b-5p negatively regulated FLT1 expression, but positively regulated the PI3K/Akt pathway in HASMCs. By referring to other previous studies, we concluded that miR-10b-5p might be a potent target in the treatment of airway diseases.

Long noncoding RNA LINC-PINT retards the abnormal growth of airway smooth muscle cells via regulating the microRNA-26a-5p/PTEN axis in asthma

BACKGROUND

Asthma is a chronic respiratory disease worldwide. This study aimed to explore the functions of the long noncoding RNA LINC-PINT (LINC-PINT) in asthma and to determine its underlying molecular mechanisms.

METHODS

Rat asthma model was established with ovalbumin sensitization and challenge. The serum level of IgE, airway hyperresponsiveness (AHR), airway inflammation, and pathological changes of lung were evaluated. Airway smooth muscle cells (ASMCs) were stimulated with platelet-derived growth factor-BB (PDGF-BB) to mimic the asthma-like condition at cellular level. QRT-PCR was performed to detect the expression of LINC-PINT, microRNA-26a-5p (miR-26a-5p), and PTEN. MTT and transwell assays were performed to measure the viability and migration of ASMCs. The protein expression of airway remodelling marker MMP-1 and MMP-9 was measured by western blot. The interactions among LINC-PINT, miR-26a-5p, and PTEN were determined by dual-luciferase reporter assay.

RESULTS

The expression of LINC-PINT and PTEN was decreased, while miR-26a-5p expression was increased in PDGF-BB-stimulated ASMCs. In vivo, overexpression of LINC-PINT decreased the serum level of IgE, AHR, airway inflammation, and pathological changes of lung in asthma rat model. In vitro, up-regulation of LINC-PINT decreased the viability, migration, and MMP-1 and MMP-9 protein expression in PDGF-BB-stimulated ASMCs. Dual-luciferase reporter assay determined that LINC-PINT targeted miR-26a-5p, and miR-26a-5p targeted PTEN in ASMCs. Feedback approaches confirmed that miR-26a-5p up-regulation or PTEN down-regulation reversed the suppressive effect of LINC-PINT overexpression on the abnormal growth of ASMCs.

CONCLUSIONS

LINC-PINT overexpression retarded the abnormal growth of ASMCs by regulating the miR-26a-5p/PTEN axis, offering a potential therapeutic target for asthma.

Dietary dimethylglycine sodium salt supplementation improves growth performance, redox status, and skeletal muscle function of intrauterine growth-restricted weaned piglets

Few studies have focused on the role of dimethylglycine sodium (DMG-Na) salt in protecting the redox status of skeletal muscle, although it is reported to be beneficial in animal husbandry. This study investigated the beneficial effects of DMG-Na salt on the growth performance, longissimus dorsi muscle (LM) redox status, and mitochondrial function in weaning piglets that were intrauterine growth restricted (IUGR). Ten normal birth weight (NBW) newborn piglets (1.53 ± 0.04 kg) and 20 IUGR newborn piglets (0.76 ± 0.06 kg) from 10 sows were obtained. All piglets were weaned at 21 d of age and allocated to the three groups with 10 replicates per group: NBW weaned piglets fed a common basal diet (N); IUGR weaned piglets fed a common basal diet (I); IUGR weaned piglets fed a common basal diet supplemented with 0.1% DMG-Na (ID). They were slaughtered at 49 d of age to collect the serum and LM samples. Compared with the N group, the growth performance, LM structure, serum, and, within the LM, mitochondrial redox status, mitochondrial respiratory chain complex activity, energy metabolites, redox status-related, cell adhesion-related, and mitochondrial function-related gene expression, and protein expression deteriorated in group I (P < 0.05). The ID group showed improved growth performance, LM structure, serum, and, within the LM, mitochondrial redox status, mitochondrial respiratory chain complex activity, energy metabolites, redox status-related, cell adhesion-related, and mitochondrial function-related gene expression, and protein expression compared with those in the I group (P < 0.05). The above results indicated that the DMG-Na salt treatment could improve the LM redox status and mitochondrial function in IUGR weaned piglets via the nuclear factor erythroid 2-related factor 2/sirtuin 1/peroxisome proliferator-activated receptorγcoactivator-1α network, thus improving their growth performance.

Megarectum: systematic histopathological evaluation of 35 patients and new common pathways in chronic rectal dilatation

AIMS

Megarectum is well described in the surgical literature but few contemporary pathological studies have been undertaken. There is uncertainty whether 'idiopathic' megarectum is a primary neuromuscular disorder or whether chronic dilatation leads to previously reported and unreported pathological changes. We sought to answer this question.

METHODS

Systematic histopathological evaluation (in accord with international guidance) of 35 consecutive patients undergoing rectal excision surgery for megarectum (primary: n=24) or megarectum following surgical correction of anorectal malformation (secondary: n=11) in a UK university hospital with adult/paediatric surgical and gastrointestinal neuropathology expertise.

RESULTS

We confirmed some previously reported observations, notably hypertrophy of the muscularis propria (27 of 35, 77.1% of patients) and extensive fibrosis (30 of 35, 85.7% of patients). We also observed unique and previously unreported features including elastosis (19 of 33, 57.6%) and the presence of polyglucosan bodies (15 of 32, 46.9% of patients). In contrast to previous literature, few patients had any strong evidence of specific forms of visceral neuropathy (5 of 35, including 3 plexus duplications) or myopathy (6 of 35, including 3 muscle duplications). All major pathological findings were common to both primary and secondary forms of the disease, implying that these may be a response to chronic rectal distension rather than of primary aetiology.

CONCLUSIONS

In the largest case series reported to date, we challenge the current perception of idiopathic megarectum as a primary neuromuscular disease and propose a cellular pathway model for the features present. The severe morphological changes account for some of the irreversibility of the condition and reinforce the need to prevent ongoing rectal distension when first identified.

An Up-Date of the Muscle Strengthening Exercise Effectiveness in Postmenopausal Women with Osteoporosis: A Qualitative Systematic Review

BACKGROUND

Osteoporosis (OP) is a systemic disease that is characterized by decreased bone density and quality. Purpose: The purpose of this systematic review was to determine the effects of muscle strengthening exercise in postmenopausal women with OP. Methods: A literature search was conducted systematically in MEDLINE, CINAHL, EMBASE databases for human studies up to 31 March 2021. Two researchers screened the articles against predefined inclusion criteria; a third resolved discrepancies. Articles were included if they assessed the effects of muscle strengthening exercise in postmenopausal women with OP. The protocol for this systematic review was registered on PROSPERO (CRD42021207917) and a qualitative systematic review was carried out following the PRISMA statement. Methodological quality was evaluated through the scientific validity scales PEDro. Finally, RTCs and NRCTs risk of bias was assessed with the Cochrane risk of bias tool (Risk of Bias-ROB 2.0) and ROBINS-1, respectively. Results: A total of 16 studies (1028 subjects) that met the different eligibility criteria previously established were selected. There is evidence of good methodological quality and a low to moderate risk of bias that supports that muscle strengthening exercise alone or in combination with other therapeutic modalities improves BMD (9, n = 401) in proximal femur and lumbar vertebra body, muscle strength (10, n = 558), balance (4, n = 159), functionality (7, n = 617), and quality of life (5, n = 291).

CONCLUSIONS

Exercise programs focused on muscle strengthening have benefits for all variables studied in postmenopausal women with OP.

miRNAs and Leukotrienes in Respiratory Syncytial Virus Infection

MicroRNAs (miRNAs) are small, non-coding RNAs that regulate posttranscription by binding to 3'-untranslated regions of target mRNAs. Recent functional studies have elucidated mechanisms that miRNAs regulate leukotriene synthesis by perturbing arachidonic acid metabolism. Both microarrays and high-throughput sequencing revealed distinct differential expression of miRNAs in children with respiratory syncytial virus (RSV) infection compared with healthy controls. Abnormal miRNA expression may contribute to higher leukotriene levels, which is associated with airway hyperreactivity. Targeting miRNAs may benefit to restore the homeostasis of inflammatory reaction and provide new strategies to alleviate airway hyperreactivity induced by RSV. In this article, we provide an overview of the current knowledge about miRNAs modulating leukotrienes through regulation of arachidonic acid metabolism with a special focus on miRNAs aberrantly expressed in children with RSV infection.

Borneol inhibits CD4 + T cells proliferation by down-regulating miR-26a and miR-142-3p to attenuate asthma

BACKGROUND

Asthma is a chronic airway inflammatory disease caused by a variety of cytokines and signaling pathways closely related to immunoregulation. Corticosteroids are the most widely used drug in the asthma treatment. However, the use of corticosteroids could cause topical side effects. So, it's important to find new drugs for asthma treatment. Our study aims to explore the pharmacological effect of borneol on asthma and its underlying mechanism.

METHODS

We constructed the OVA-induced asthma model to investigate the effect of borneol on asthma in mice. HE and PAS staining was used to detect the effect of borneol on pathological change of mice with asthma. Inflammatory cytokines were measured by ELISA. qRT-PCR was used to explore the effect of borneol on microRNAs expression. Cell proliferation of CD4 + T cells was detected by CCK-8 assay and flow cytometry. Western blot was used to detect pten expression and Akt activation.

RESULTS

We found that borneol significantly alleviated asthma progression in mice. Borneol inhibited CD4 + T cells infiltration in vivo and proliferation in vitro by downregulating miR-26a and miR-142-3p. miR-26a and miR-142-3p promoted CD4 + T cells proliferation in vitro through targeting Pten. Overexpression of miR-26a and miR-142-3p abolished the effect of borneol in vivo.

CONCLUSION

In a word, these findings suggested that borneol attenuated asthma in mice by decreasing the CD4 + T cells infiltration. The molecular mechanism of borneol was dependent on the downregulation of miR-26a and miR-142-3p to upregulate the Pten expression.

miR-26 family and its target genes in tumorigenesis and development

The microRNA-26 family, including miR-26a, miR-26b, miR-1297 and miR-4465, is a group of broadly conserved small RNAs with identical sequences at the seed region. The expression of miR-26 could be induced by hypoxia via a HIF-dependent mechanism, and up-regulated during multiple cell differentiation. Accumulating studies have demonstrated that miR-26 family members could be detected in many different kinds of tumors, and their validated target genes are involved in cell metabolism, proliferation, differentiation, apoptosis, invasion and metastasis. The expression of miR-26 might be a potentially valuable biomarker and a new target for cancer therapy. In this review, miR-26 family and its target genes in tumorigenesis and development will be summarized as follows.

Transcriptomic profile of semitendinosus muscle of bulls of different breed and performance

The aim of the study was to compare the transcriptomic profiles of fully differentiated skeletal muscle derived from bulls belonging to different breeds of varying performance. Microarray analyses were performed to determine the differences in the expression profiles of genes between semitendinosus muscles of 15-month-old beef-breed bulls (Limousin—LIM and Hereford—HER) and dairy-breed bulls (Holstein Friesian—HF). These analyses allowed for the identification of those genes the expression of which is similar and characteristic of fully differentiated muscle in beef breeds, but differs in skeletal muscle of a typical dairy breed. The analysis revealed 463 transcripts showing similar expression in the semitendinosus muscle of beef breeds (LIM/HER), in comparison with the dairy breed (HF). Among the identified genes, 227 were upregulated and 236 were downregulated in beef breeds. The ontological analyses revealed that the largest group of genes similarly expressed in LIM and HER was involved in the processes of protein metabolism and development of muscle organ. In beef breeds, some genes involved in protein synthesis and proteolysis showed an upregulation, including ctsd, ctsf, fhl2, fhl3, fst, sirt1, and trim63, whereas some were downregulated, including bmpr1a, bmpr2, mstn, smad2, hspa8, gsk3β, and tgfβ2. The expression of the chosen genes was confirmed by RT-qPCR technique. Thus, it can be assumed that the identified genes involved in the regulation of growth and development of muscle tissue and the processes of protein metabolism in the examined cattle breeds may be responsible for the greater gain of muscle mass in beef-breed bulls.

Muscle-specific sirtuin1 gain-of-function ameliorates skeletal muscle atrophy in a pre-clinical mouse model of cerebral ischemic stroke

Stroke causes severe long-term disability in patients due to the induction of skeletal muscle atrophy and weakness, but the molecular mechanisms remain elusive. Using a preclinical mouse model of cerebral ischemic stroke, we show that stroke robustly induced atrophy and significantly decreased SirT1 gene expression in the PTA (paralytic tibialis anterior) muscle. Muscle-specific SirT1 gain-of-function mice are resistant to stroke-induced muscle atrophy and this protective effect requires its deacetylase activity. Although SirT1 counteracts the stroke-induced up-regulation of atrogin1, MuRF1 and ZNF216 genes, we found a mechanism that regulates the ZNF216 gene transcription in post-stroke muscle. Stroke increased the expression of the ZNF216 gene in PTA muscle by activating PARP-1, which binds on the ZNF216 promoter. The SirT1 gain-of-function or SirT1 activator, resveratrol, reversed the PARP-1-mediated up-regulation of ZNF216 expression at the promoter level, suggesting a contradicted role for SirT1 and PARP-1 in the regulation of ZNF216 gene. Overall, our study for the first-time demonstrated that (a) stroke causes muscle atrophy, in part, through the SirT1/PARP-1/ZNF216 signaling mechanism; (b) SirT1 can block muscle atrophy in response to different types of atrophic signals via different signaling mechanisms; and (c) SirT1 is a critical regulator of post-stroke muscle mass.

A Network of Sputum MicroRNAs Is Associated with Neutrophilic Airway Inflammation in Asthma

Rationale: MicroRNAs are potent regulators of biologic systems that are critical to tissue homeostasis. Individual microRNAs have been identified in airway samples. However, a systems analysis of the microRNA-mRNA networks present in the sputum that contribute to airway inflammation in asthma has not been published.Objectives: Identify microRNA and mRNA networks in the sputum of patients with asthma.Methods: We conducted a genome-wide analysis of microRNA and mRNA in the sputum from patients with asthma and correlated expression with clinical phenotypes. Weighted gene correlation network analysis was implemented to identify microRNA networks (modules) that significantly correlate with clinical features of asthma and mRNA expression networks. MicroRNA expression in peripheral blood neutrophils and lymphocytes and in situ hybridization of the sputum were used to identify the cellular sources of microRNAs. MicroRNA expression obtained before and after ozone exposure was also used to identify changes associated with neutrophil counts in the airway.Measurements and Main Results: Six microRNA modules were associated with clinical features of asthma. A single module (nely) was associated with a history of hospitalizations, lung function impairment, and numbers of neutrophils and lymphocytes in the sputum. Of the 12 microRNAs in the nely module, hsa-miR-223-3p was the highest expressed microRNA in neutrophils and was associated with increased neutrophil counts in the sputum in response to ozone exposure. Multiple microRNAs in the nely module correlated with two mRNA modules enriched for TLR (Toll-like receptor) and T-helper cell type 17 (Th17) signaling and endoplasmic reticulum stress. hsa-miR-223-3p was a key regulator of the TLR and Th17 pathways in the sputum of subjects with asthma.Conclusions: This study of sputum microRNA and mRNA expression from patients with asthma demonstrates the existence of microRNA networks and genes that are associated with features of asthma severity. Among these, hsa-miR-223-3p, a neutrophil-derived microRNA, regulates TLR/Th17 signaling and endoplasmic reticulum stress.

Transcriptome Analysis of Skeletal Muscle Reveals Altered Proteolytic and Neuromuscular Junction Associated Gene Expressions in a Mouse Model of Cerebral Ischemic Stroke

Stroke is a leading cause of mortality and long-term disability in patients worldwide. Skeletal muscle is the primary systemic target organ of stroke that induces muscle wasting and weakness, which predominantly contribute to functional disability in stroke patients. Currently, no pharmacological drug is available to treat post-stroke muscle morbidities as the mechanisms underlying post-stroke muscle wasting remain poorly understood. To understand the stroke-mediated molecular changes occurring at the transcriptional level in skeletal muscle, the gene expression profiles and enrichment pathways were explored in a mouse model of cerebral ischemic stroke via high-throughput RNA sequencing and extensive bioinformatic analyses. RNA-seq revealed that the elevated muscle atrophy observed in response to stroke was associated with the altered expression of genes involved in proteolysis, cell cycle, extracellular matrix remodeling, and the neuromuscular junction (NMJ). These data suggest that stroke primarily targets muscle protein degradation and NMJ pathway proteins to induce muscle atrophy. Collectively, we for the first time have found a novel genome-wide transcriptome signature of post-stroke skeletal muscle in mice. Our study will provide critical information to further elucidate specific gene(s) and pathway(s) that can be targeted to mitigate accountable for post-stroke muscle atrophy and related weakness.

Expression Level of MiRNA-126 in Serum Exosomes of Allergic Asthma Patients and Lung Tissues of Asthmatic Mice

BACKGROUND

To investigate MiRNA-126 amounts in serum exosomes from allergic asthma patients as well as lung tissues of asthmatic mice, evaluating the expression of its target gene DNMT1 in mouse specimens.

METHODS

MiRNA-126 amounts in serum exosomes from asthmatic patients were detected by real-time PCR. The mouse model of allergic asthma was established by OVA-sensitization, and allergic symptoms were recorded; serum IL-4 and sIgE level evaluation (ELISA), broncho alveolar lavage fluid (BALF) cell count and H&E staining were performed to assess airway inflammation. MiRNA-126 and DNMT1 levels in the lung of asthmatic and control mice were detected by real-time PCR; DNMT1 protein levels were detected by immunoblot.

RESULTS

MiRNA-126 amounts in peripheral blood exosomes from patients with allergic asthma were significantly higher than that of healthy volunteers (P<0.05). The frequencies of scratching of both sides of the nose and sneezing were elevated within 10 min of excitation in asthmatic rats compared with controls. Meanwhile, OVA-sIgE and IL-4 levels were significantly higher in asthmatic animals than controls (P<0.05). In the asthma group, narrowed bronchial lumen and thickened wall were observed, and bronchial and peripheral vessels showed overt inflammatory cell infiltration. Eosinophil, neutrophil and mast cell amounts in the BALF of asthmatic mice were significantly higher than control values. Furthermore, lung miRNA-126 expression in asthmatic mice was significantly higher than that of controls. Finally, DNMT1 mRNA and protein levels were significantly lower in asthmatic animals compared with controls (P < 0.01).

CONCLUSION

MiRNA-126 is highly expressed in serum exosomes from allergic asthma patients and lung tissues of asthmatic mice, suggesting that it may be involved in the pathogenesis of bronchial asthma.

Pancreatic β cell microRNA-26a alleviates type 2 diabetes by improving peripheral insulin sensitivity and preserving β cell function

Type 2 diabetes (T2D) is characterized by insulin resistance along with pancreatic β cell failure. β cell factors are traditionally thought to control glucose homeostasis by modulating insulin levels, not insulin sensitivity. Exosomes are emerging as new regulators of intercellular communication. However, the role of β-cell–derived exosomes in metabolic homeostasis is poorly understood. Here, we report that microRNA-26a (miR-26a) in β cells not only modulates insulin secretion and β cell replication in an autocrine manner but also regulates peripheral insulin sensitivity in a paracrine manner through circulating exosomes. MiR-26a is reduced in serum exosomes of overweight humans and is inversely correlated with clinical features of T2D. Moreover, miR-26a is down-regulated in serum exosomes and islets of obese mice. Using miR-26a knockin and knockout mouse models, we showed that miR-26a in β cells alleviates obesity-induced insulin resistance and hyperinsulinemia. Mechanistically, miR-26a in β cells enhances peripheral insulin sensitivity via exosomes. Meanwhile, miR-26a prevents hyperinsulinemia through targeting several critical regulators of insulin secretion and β cell proliferation. These findings provide a new paradigm for the far-reaching systemic functions of β cells and offer opportunities for the treatment of T2D.

A study using mouse models and human samples reveals a previously unknown role for pancreatic β-cell regulators in glucose homeostasis, in which β cell miR-26a not only modulates insulin secretion and β cell replication in an autocrine manner but also regulates peripheral insulin sensitivity in a paracrine manner through circulating exosomes.

A novel inhibitory role of microRNA-224 in particulate matter 2.5-induced asthmatic mice by inhibiting TLR2

Epidemiological studies have shown that elevated concentrations of particulate matter 2.5 (PM2.5) correlate with increased incidence of asthma. Studies have highlighted the implication of microRNAs (miRNAs) in asthmatic response. Here, the objective of this study is to explore the effect of miR-224 on PM2.5-induced asthmatic mice. Ovalbumin (OVA) was utilized to establish asthmatic mouse models, which were then exposed to PM2.5, followed by miR-224 expression detection. Next, lesions and collagen deposition area in lung tissue, ratio Treg/Th17, the expression of TLR4 and MYD88, inflammation, eosinophils (EOS) and airway remodelling were evaluated in OVA mice after injection with miR-224 agomir. Following isolation of mouse primary bronchial epithelial cells, miR-224 mimic and TLR2/TLR4 inhibitor were introduced to assess inflammation and the expression of TGF-β, MMP9, TIMP-1, Foxp3, RORγt, TLR2, TLR4 and MYD88. After exposure to PM2.5, lesions and collagen deposition were promoted in lung tissues, inflammation and EOS were increased in bronchoalveolar lavage fluid (BALF), and airway remodelling was enhanced in OVA mice. miR-224 was down-regulated, whereas TLR2/TLR4/MYD88 was up-regulated in OVA mice after treatment with PM2.5, accompanied by Treg/Th17 immune imbalance. Of note, bioinformatic prediction and dual luciferase reporter gene assay confirmed that TLR2 was a target gene of miR-224. Overexpressed miR-224 reduced expression of TGF-β, MMP9, TIMP-1 and RORγt and inflammation but increased Foxp3 expression in bronchial epithelial cells through down-regulating TLR2. In summary, overexpressed miR-224 suppressed airway epithelial cell inflammation and airway remodelling in PM2.5-induced asthmatic mice through decreasing TLR2 expression.

Exogenous miR-26a suppresses muscle wasting and renal fibrosis in obstructive kidney disease

Kidney fibrosis occurs in almost every type of chronic kidney disease. We found that microRNA (miR)-26a was decreased in the kidney, muscle, and exosomes of unilateral ureteral obstruction (UUO) mice. We hypothesized that exogenous miR-26 could suppresses renal fibrosis and muscle wasting in obstructive kidney disease. For this purpose, we generated exosomes that encapsulated miR-26, then injected these into skeletal muscle of UUO mice. The expression of miR-26a was elevated in serum exosomes from UUO mice following exosome-miR-26a injection. In these mice, muscle wasting has been ameliorated as evidenced by increased muscle weights. In addition, a muscle atrophy marker, myostatin, is increased in UUO muscle; provision of miR-26a abolished this increase. We detected a remote effect of exosomes containing miR-26a in UUO-induced renal fibrosis. The intervention of miR-26a attenuated UUO-induced renal fibrosis as determined by immunohistological assessment of α-smooth muscle actin and Masson's trichrome staining. Furthermore, exogenous miR-26a decreased the protein levels of 2 profibrosis proteins, connective tissue growth factor (CTGF) and TGF-β1, in UUO kidney. Our data showed that exosomes containing miR-26a prevented muscle atrophy by inhibiting the transcription factor forkhead box O1. Likewise, the exosome-carried miR-26a limited renal fibrosis by directly suppressing CTGF. Our findings provide an experimental basis for exosome-mediated therapy of muscle atrophy and renal fibrosis.-Zhang, A., Wang, H., Wang, B., Yuan, Y., Klein, J. D., Wang, X. H. Exogenous miR-26a suppresses muscle wasting and renal fibrosis in obstructive kidney disease.

Epigenetics in Asthma

PURPOSE OF REVIEW

Asthma is one of the most common chronic respiratory diseases linked with increased morbidity and healthcare utilization. The underlying pathophysiological processes and causal relationships of asthma with epigenetic mechanisms are partially understood. Here we review human studies of epigenetic mechanisms in asthma, with a special focus on DNA methylation.

RECENT FINDINGS

Epigenetic studies of childhood asthma have identified specific methylation signatures associated with allergic inflammation in the airway and immune cells, demonstrating a regulatory role for methylation in asthma pathogenesis. Despite these novel findings, additional research in the role of epigenetic mechanisms underlying asthma endotypes is needed. Similarly, studies of histone modifications are also lacking in asthma. Future studies of epigenetic mechanisms in asthma will benefit from data integration in well phenotyped cohorts. This review provides an overview of the current literature on epigenetic studies in human asthma, with special emphasis on methylation and childhood asthma.

Consistent Biomarkers and Related Pathogenesis Underlying Asthma Revealed by Systems Biology Approach

Asthma is a common chronic airway disease worldwide. Due to its clinical and genetic heterogeneity, the cellular and molecular processes in asthma are highly complex and relatively unknown. To discover novel biomarkers and the molecular mechanisms underlying asthma, several studies have been conducted by focusing on gene expression patterns in epithelium through microarray analysis. However, few robust specific biomarkers were identified and some inconsistent results were observed. Therefore, it is imperative to conduct a robust analysis to solve these problems. Herein, an integrated gene expression analysis of ten independent, publicly available microarray data of bronchial epithelial cells from 348 asthmatic patients and 208 healthy controls was performed. As a result, 78 up- and 75 down-regulated genes were identified in bronchial epithelium of asthmatics. Comprehensive functional enrichment and pathway analysis revealed that response to chemical stimulus, extracellular region, pathways in cancer, and arachidonic acid metabolism were the four most significantly enriched terms. In the protein-protein interaction network, three main communities associated with cytoskeleton, response to lipid, and regulation of response to stimulus were established, and the most highly ranked 6 hub genes (up-regulated CD44, KRT6A, CEACAM5, SERPINB2, and down-regulated LTF and MUC5B) were identified and should be considered as new biomarkers. Pathway cross-talk analysis highlights that signaling pathways mediated by IL-4/13 and transcription factor HIF-1α and FOXA1 play crucial roles in the pathogenesis of asthma. Interestingly, three chemicals, polyphenol catechin, antibiotic lomefloxacin, and natural alkaloid boldine, were predicted and may be potential drugs for asthma treatment. Taken together, our findings shed new light on the common molecular pathogenesis mechanisms of asthma and provide theoretical support for further clinical therapeutic studies.

MicroRNA-221 is overexpressed in the equine asthmatic airway smooth muscle and modulates smooth muscle cell proliferation

Airway wall remodeling, including hyperplasia and hypertrophy of smooth muscle (ASM) cells leading to an increased smooth muscle mass, is considered central to asthma. However, molecular pathways responsible for ASM remodeling remain poorly understood. MicroRNAs (miRNAs) have emerged as key regulators of inflammatory and repair processes affecting the lungs and can downregulate protein expression by inhibiting target mRNA translation. We therefore hypothesized that miRNAs are involved in ASM remodeling in asthma by modulating ASM proliferation. We have analyzed the expression of miRNAs in bronchial smooth muscle from asthmatic horses during disease exacerbation and remission and from controls. Their involvement in ASM cell proliferation was then studied. Our results shown that miR-26a, miR-133, and miR-221 were upregulated in ASM from horses with asthma exacerbation compared with asthma remission and controls. MiR-221 induced cell hyperproliferation and reduced the expression of contractile gene markers in ASM cells. These changes were associated with the decreased mRNA expression of cell cycle regulatory genes (p53, p21, and p27). In conclusion, we demonstrated for the first time an upregulation of miR-221 in asthmatic airway smooth muscle and confirm the involvement of miR-221 in ASM cell proliferation by regulation of the cell cycle arrest genes. Targeting miR-221 network genes may represent a novel approach for the treatment of ASM remodeling in asthma.

Mechanosensitive MiRs regulated by anabolic and catabolic loading of human cartilage

OBJECTIVE

Elucidation of whether miRs are involved in mechanotransduction pathways by which cartilage is maintained or disturbed has a particular importance in our understanding of osteoarthritis (OA) pathophysiology. The aim was to investigate whether mechanical loading influences global miR-expression in human chondrocytes and to identify mechanosensitive miRs responding to beneficial and non-beneficial loading regimes as potential to obtain valuable diagnostic or therapeutic targets to advance OA-treatment.

METHOD

Mature tissue-engineered human cartilage was subjected to two distinct loading regimes either stimulating or suppressing proteoglycan-synthesis, before global miR microarray analysis. Promising candidate miRs were selected, re-evaluated by qRT-PCR and tested for expression in human healthy vs OA cartilage samples.

RESULTS

After anabolic loading, miR microarray profiling revealed minor changes in miR-expression while catabolic stimulation produced a significant regulation of 80 miRs with a clear separation of control and compressed samples by hierarchical clustering. Cross-testing of selected miRs revealed that miR-221, miR-6872-3p, miR-6723-5p were upregulated by both loading conditions while others (miR-199b-5p, miR-1229-5p, miR-1275, miR-4459, miR-6891-5p, miR-7150) responded specifically after catabolic loading. Mechanosensitivity of miR-221 correlated with pERK1/2-activation induced by both loading conditions. The miR-response to loading was transient and a constitutive deregulation of mechano-miRs in OA vs healthy articular cartilage was not observed.

CONCLUSIONS

MiRs with broader vs narrower mechanosensitivity were discovered and the first group of mechanosensitive miRs characteristic for non-beneficial loading was defined that may shape the proteome differentially when cartilage tissue is disturbed. The findings prompt future investigations into miR-relevance for mechano-responsive pathways and the corresponding miR-target molecules.

Neuroepigenetics and Alzheimer's Disease: An Update

Epigenetics is the study of changes in gene expression which may be triggered by both genetic and environmental factors, and independent from changes to the underlying DNA sequence-a change in phenotype without a change in genotype-which in turn affects how cells read genes. Epigenetic changes represent a regular and natural occurrence but can be influenced also by factors such as age, environment, and disease state. Epigenetic modifications can manifest themselves not only as the manner in which cells terminally differentiate, but can have also deleterious effects, resulting in diseases such as cancer. At least three systems including DNA methylation, histone modification, and non-coding RNA (ncRNA)-associated gene silencing are thought to initiate and sustain epigenetic change. For example, in Alzheimer's disease (AD), both genetic and non-genetic factors contribute to disease etiopathology. While over 250 gene mutations have been related to familial AD, less than 5% of AD cases are explained by known disease genes. More than likely, non-genetic factors, probably triggered by environmental factors, are causative factors of late-onset AD. AD is associated with dysregulation of DNA methylation, histone modifications, and ncRNAs. Among the classes of ncRNA, microRNAs (miRNAs) have a well-established regulatory relevance. MicroRNAs are highly expressed in CNS neurons, where they play a major role in neuron differentiation, synaptogenesis, and plasticity. MicroRNAs impact higher cognitive functions, as their functional impairment is involved in the etiology of neurological diseases, including AD. Alterations in the miRNA network contribute to AD disease processes, e.g., in the regulation of amyloid peptides, tau, lipid metabolism, and neuroinflammation. MicroRNAs, both as biomarkers for AD and therapeutic targets, are in the early stages of exploration. In addition, emerging data suggest that altered transcription of long ncRNAs, endogenous, ncRNAs longer than 200 nucleotides, may be involved in an elevated risk for AD.

MicroRNA expression profile is altered in the upper airway skeletal muscle tissue of patients with obstructive sleep apnea-hypopnea syndrome

Objective

To investigate the involvement of microRNAs (miRNAs) in the pathogenesis of obstructive sleep apnea-hypopnea syndrome (OSAHS).

Methods

In this study, we investigated miRNA profiles in the upper airway (UA) skeletal muscles of four patients with OSAHS and four matched controls using the miRCURY miRNA array. In another cohort of 12 OSAHS cases and 7 controls, the mRNA expression levels of interleukin (IL)-6 and Lin-28 homolog A (Lin28A), targets of the downregulated let-7 family members, were measured by real-time quantitative-PCR. The potential targets of the miRNAs were predicted by miRNA target prediction databases miRanda, Microcosm, and Targetscan.

Results

The array identified 370 differentially expressed miRNAs, of which 181 were upregulated and 189 were downregulated in OSAHS patients (based on a fold-change >2.0 and p < 0.05). Upregulation of IL-6 and Lin28A was validated by quantitative reverse transcription PCR. The 612 targets predicted by all three algorithms were subjected to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The results revealed perturbations in signaling pathways and cellular functions.

Conclusion

This study demonstrated profoundly altered miRNA expression profiles in upper airway muscular tissues of patients with OSAHS, which might contribute to the formation and development of OSAHS.

Role of TRPC1 channels in pressure-mediated activation of airway remodeling

BACKGROUND

Bronchoconstriction and cough, a characteristic of the asthmatic response, leads to development of compressive stresses in the airway wall. We hypothesized that progressively pathological high mechanical stress could act on mechanosensitive cation channels, such as transient receptor potential channel 1 (TRPC1) and then contributes to airway remodeling.

METHODS

We imitate the pathological airway pressure in vitro using cyclic stretch at 10 and 15% elongation. Ca2+ imaging was applied to measure the activity of TRPC1 after bronchial epithelial cells exposed to cyclic stretch for 0, 0.5, 1, 1.5, 2, 2.5 h. To further clarify the function of channnel TRPC1 in the process of mechano-transduction in airway remodeling, the experiment in vivo was implemented. The TRPC1 siRNA and budesonide were applied separately to asthmatic models. The morphological changes were measured by HE and Massion method. The expression levels of TRPC1 were evaluated by real-time PCR, western blot and immunohistochemistry. The protein expression level of IL-13, TGF-β1 and MMP-9 in BALF were measured by ELISA.

RESULTS

The result showed that cyclic stretch for 15% elongation at 1.5 h could maximize the activity of TRPC1 channel. This influx in Ca2+ was blocked by TRPC1 siRNA. Higher TRPC1 expression was observed in the bronchial epithelial layer of ovalbumin induced asthmatic models. The knockdown of TRPC1 with TRPC1 siRNA was associated with a hampered airway remodeling process, such as decreased bronchial wall thickness and smooth muscle hypertrophy/hyperplasia, a decreased ECM deposition area and inflammation infiltration around airway wall. Meantime, expression of IL-13, TGF-β1 and MMP-9 in OVA+TRPC1 siRNA also showed reduced level. TRPC1 intervention treatment showed similar anti-remodeling therapeutic effect with budesonide.

CONCLUSIONS

These results demonstrate that most TRPC1 channels expressed in bronchial epithelial cells mediate the mechanotransduction mechanism. TRPC1 inducing abnormal Ca2+ signal mediates receptor-stimulated and mechanical stimulus-induced airway remodeling. The inhibition of TRPC1 channel could produce similar therapeutic effect as glucocortisteroid to curb the development of asthmatic airway remodeling.

Pressure suppresses hepatocellular glycogen synthesis through activating the p53/Pten pathway

Portal hypertension is the primary cause of complications in patients with chronic liver diseases, and markedly impacts metabolism within the nervous system. Until recently, the role of portal hypertension in hepatocellular metabolism was unclear. The present study demonstrated that an increase in extracellular pressure significantly decreased hepatocellular glycogen concentrations in HepG2 and HL-7702 cells. In addition, it reduced glycogen synthase activity, by inhibiting the phosphorylation of glycogen synthase 1. RNA-seq analysis revealed that mechanical pressure suppressed glycogen synthesis by activating the p53/phosphatase and tensin homolog pathway, further suppressing glycogen synthase activity. The present study revealed an association between mechanical pressure and hepatocellular glycogen metabolism, and identified the regulatory mechanism of glycogen synthesis under pressure.

MicroRNA-26a/Death-Associated Protein Kinase 1 Signaling Induces Synucleinopathy and Dopaminergic Neuron Degeneration in Parkinson's Disease

BACKGROUND

Death-associated protein kinase 1 (DAPK1) is a widely distributed serine/threonine kinase that is critical for cell death in multiple neurological disorders, including Alzheimer's disease and stroke. However, little is known about the role of DAPK1 in the pathogenesis of Parkinson's disease (PD), the second most common neurodegenerative disorder.

METHODS

We used Western blot and immunohistochemistry to evaluate the alteration of DAPK1. Quantitative polymerase chain reaction and fluorescence in situ hybridization were used to analyze the expression of microRNAs in PD mice and patients with PD. Rotarod, open field, and pole tests were used to evaluate the locomotor ability. Immunofluorescence, Western blot, and filter traps were used to evaluate synucleinopathy in PD mice.

RESULTS

We found that DAPK1 is posttranscriptionally upregulated by a reduction in microRNA-26a (miR-26a) caused by a loss of the transcription factor CCAAT enhancer-binding protein alpha. The overexpression of DAPK1 in PD mice is positively correlated with neuronal synucleinopathy. Suppressing miR-26a or upregulating DAPK1 results in synucleinopathy, dopaminergic neuron cell death, and motor disabilities in wild-type mice. In contrast, genetic deletion of DAPK1 in dopaminergic neurons by crossing DAT-Cre mice with DAPK1 floxed mice effectively rescues the abnormalities in mice with chronic MPTP treatment. We further showed that DAPK1 overexpression promotes PD-like phenotypes by direct phosphorylation of α-synuclein at the serine 129 site. Correspondingly, a cell-permeable competing peptide that blocks the phosphorylation of α-synuclein prevents motor disorders, synucleinopathy, and dopaminergic neuron loss in the MPTP mice.

CONCLUSIONS

miR-26a/DAPK1 signaling cascades are essential in the formation of the molecular and cellular pathologies in PD.

The Effect of Exercise on the Prevention of Osteoporosis and Bone Angiogenesis

Physical activity or appropriate exercise prevents the development of osteoporosis. However, the exact mechanism remains unclear although it is well accepted that exercise or mechanical loading regulates the hormones, cytokines, signaling pathways, and noncoding RNAs in bone. Accumulating evidence has shown that bone is a highly vascularized tissue, and dysregulation of vasculature is associated with many bone diseases such as osteoporosis or osteoarthritis. In addition, exercise or mechanical loading regulates bone vascularization in bone microenvironment via the modulation of angiogenic mediators, which play a crucial role in maintaining skeletal health. This review discusses the effects of exercise and its underlying mechanisms for osteoporosis prevention, as well as an angiogenic and osteogenic coupling in response to exercise.

Epigenetic Modulation on Tau Phosphorylation in Alzheimer's Disease

Tau hyperphosphorylation is a typical pathological change in Alzheimer's disease (AD) and is involved in the early onset and progression of AD. Epigenetic modification refers to heritable alterations in gene expression that are not caused by direct changes in the DNA sequence of the gene. Epigenetic modifications, such as noncoding RNA regulation, DNA methylation, and histone modification, can directly or indirectly affect the regulation of tau phosphorylation, thereby participating in AD development and progression. This review summarizes the current research progress on the mechanisms of epigenetic modification associated with tau phosphorylation.

miR-26a Limits Muscle Wasting and Cardiac Fibrosis through Exosome-Mediated microRNA Transfer in Chronic Kidney Disease

Uremic cardiomyopathy and muscle atrophy are associated with insulin resistance and contribute to chronic kidney disease (CKD)-induced morbidity and mortality. We hypothesized that restoration of miR-26a levels would enhance exosome-mediated microRNA transfer to improve muscle wasting and cardiomyopathy that occur in CKD.

Methods: Using next generation sequencing and qPCR, we found that CKD mice had a decreased level of miR-26a in heart and skeletal muscle. We engineered an exosome vector that contained Lamp2b, an exosomal membrane protein gene fused with a muscle-specific surface peptide that targets muscle delivery. We transfected this vector into muscle satellite cells and then transduced these cells with adenovirus that expresses miR-26a to produce exosomes encapsulated miR-26a (Exo/miR-26a). Exo/miR-26a was injected once per week for 8 weeks into the tibialis anterior (TA) muscle of 5/6 nephrectomized CKD mice.

Results: Treatment with Exo/miR-26a resulted in increased expression of miR-26a in skeletal muscle and heart. Overexpression of miR-26a increased the skeletal muscle cross-sectional area, decreased the upregulation of FBXO32/atrogin-1 and TRIM63/MuRF1 and depressed cardiac fibrosis lesions. In the hearts of CKD mice, FoxO1 was activated, and connective tissue growth factor, fibronectin and collagen type I alpha 1 were increased. These responses were blunted by injection of Exo/miR-26a. Echocardiograms showed that cardiac function was improved in CKD mice treated with Exo/miR-26a.

Conclusion: Overexpression of miR-26a in muscle prevented CKD-induced muscle wasting and attenuated cardiomyopathy via exosome-mediated miR-26a transfer. These results suggest possible therapeutic strategies for using exosome delivery of miR-26a to treat complications of CKD.

TGF-β1 induces airway smooth muscle cell proliferation and remodeling in asthmatic mice by up-regulating miR-181a and suppressing PTEN

Several studies have shown that transforming growth factor β1 (TGF-β1) plays a crucial role in remodeling and proliferation of airway smooth muscle cells (ASMCs). However, its molecular mechanism needs to be further studied. TGF-β1 can up-regulate the level of miR-181a in multiple cells, while miR-181a is expressed in asthma. We asked whether TGF-β1 plays a role in asthma through regulation of miR-181a. For this purpose, ASMCs were stimulated with TGF-β1 and the expression level of miR-181a and extracellular matrix (ECM) protein were measured by quantitative real time polymerase chain reaction (qRT-PCR) and western blotting. The cell proliferation and migration ability of TGF-β1-induced ASMCs were detected by Cell Counting Kit-8 (CCK-8) and transwell method, respectively. Luciferase assay was used to verify whether PTEN is a direct target of miR-181a in ASMCs. miR-181a expression level was increased in TGF-β1-induced ASMCs and miR-181a could inhibit the cell proliferation, migration, and excessive secretion of ECM. The results of the luciferase assay showed that miR-181a plays a role in TGF-β1-induced ASMCs targeting PTEN and the results of western blotting indicated that TGF-β1 could activate Akt/mTOR signaling pathway by up-regulating miR-181a and down-regulating siPTEN. In conclusion, TGF-β1 may induce airway smooth muscle cell proliferation and airway remodeling of asthma by up-regulating miR-181a and suppressing PTEN, and miR-181a inhibitor may function as an inhibitor of ASMCs proliferation through inactivation of the Akt/mTOR pathway.

Lentivirus‑mediated microRNA‑26a overexpression in bone mesenchymal stem cells facilitates bone regeneration in bone defects of calvaria in mice

Repair of bone defects presents a serious clinical challenge as it is difficult to restore bone function and regenerate bone loss. In the present study, the effects of lentivirus-mediated transfection of bone marrow mesenchymal stem cells (BMSCs) with microRNA (miR)-26a on bone regeneration were investigated in a mouse bone defect repair model. Marker of proliferation Ki67 (Ki67) staining was employed to detect the cell proliferation capacity and alkaline phosphatase (ALP) staining was used to investigate osteogenic differentiation. A mouse model of cranial bone defects was established. β-tricalcium phosphate biomaterials co-cultured with the transfected BMSCs were implanted into the defect areas of mouse models. Micro-computed tomography, and hematoxylin and eosin and toluidine blue staining, were used to detect bone regeneration in the defect areas and the degradation of scaffolds. miR-26a expression, and the mRNA and protein expression of osteogenesis-associated cytokines, were detected using reverse transcription-quantitative polymerase chain reaction and western blot analysis. Separated and cultured BMSCs highly expressed CD29 and CD105, but not CD34 and CD45, as determined by flow cytometry. miR-26a expression and the positive cell rate of Ki67 and ALP staining in BMSCs transfected with pLVTHM-miR-26a were increased. The BMSC and negative control-transfected BMSC groups exhibited increased bone regeneration in the defect areas, increased bone volume of newly formed bones, and elevated mRNA and protein expression of runt-related transcription factor 2 (Runx2) and osteocalcin (OC), compared with the blank group. However, the miR-26a-transfected BMSC group exhibited further increases in bone regeneration and the volume of newly formed bones, and further elevations of the mRNA and protein expression levels of Runx2 and OC. The present findings demonstrated that lentivirus-mediated modification of BMSCs enhanced bone regeneration during the repair of cranial bone defects in mice.