MiR-15b and miR-322 inhibit SETD3 expression to repress muscle cell differentiation

Targeting Crosstalk of Signaling Pathways among Muscles-Bone-Adipose Tissue: A Promising Therapeutic Approach for Sarcopenia

The aging process is associated with the development of a wide range of degenerative disorders in mammals. These diseases are characterized by a progressive decline in function at multiple levels, including the molecular, cellular, tissue, and organismal. Furthermore, it is responsible for various healthcare costs in developing and developed countries. Sarcopenia is the deterioration in the quality and functionality of muscles, which is extremely concerning as it manages many functions in the human body. This article reviews the molecular crosstalk involved in sarcopenia and the specific roles of many mediator molecules in establishing cross-talk between muscles, bone, and fatty tissues, eventually leading to sarcopenia. Besides, the involvement of various etiological factors, such as neurology, endocrinology, lifestyle, etc., makes it exceedingly difficult for clinicians to develop a coherent hypothesis that may lead to the well-organized management system required to battle this debilitating disease. The several hallmarks contributing to the progression of the disease is a vital question that needs to be addressed to ensure an efficient treatment for sarcopenia patients. Also, the intricate molecular mechanism involved in developing this disease requires more studies. The direct relationship of cellular senescence with aging is one of the pivotal issues contributing to disease pathophysiology. Some patented treatment strategies have been discussed, including drugs undergoing clinical trials and emerging options like miRNA and protein-enclosed extracellular vesicles. A clear understanding of the secretome, including the signaling pathways involved between muscles, bone, and fatty tissues, is extremely beneficial for developing novel therapeutics for curing sarcopenia.

An Updated Review on the Significance of DNA and Protein Methyltransferases and De-methylases in Human Diseases: From Molecular Mechanism to Novel Therapeutic Approaches

Epigenetic mechanisms are crucial in regulating gene expression. These mechanisms include DNA methylation and histone modifications, like methylation, acetylation, and phosphorylation. DNA methylation is associated with gene expression suppression; however, histone methylation can stimulate or repress gene expression depending on the methylation pattern of lysine or arginine residues on histones. These modifications are key factors in mediating the environmental effect on gene expression regulation. Therefore, their aberrant activity is associated with the development of various diseases. The current study aimed to review the significance of DNA and histone methyltransferases and demethylases in developing various conditions, like cardiovascular diseases, myopathies, diabetes, obesity, osteoporosis, cancer, aging, and central nervous system conditions. A better understanding of the epigenetic roles in developing diseases can pave the way for developing novel therapeutic approaches for affected patients.

miR-322 promotes the differentiation of embryonic stem cells into cardiomyocytes

Previous studies have shown that miR-322 regulates the functions of various stem cells. However, the role and mechanism of embryonic stem cell (ESCs) differentiation into cardiomyocytes remains unknown. Celf1 plays a vital role in stem cell differentiation and may be a potential target of miR-322 in ESCs' differentiation. We studied the function of miR-322An using mESCs transfected with lentivirus-mediated miR-322. RT-PCR results indicated that miR-322 increased NKX-2.5, MLC2V, and α-MHC mRNA expression, signifying that miR-322 might promote the differentiation of ESCs toward cardiomyocytes in vitro. The western blotting and immunofluorescence results confirmed this conclusion. In addition, the knockdown of miR-322 expression inhibited ESCs' differentiation toward cardiomyocytes in cultured ESCs in vitro. Western blotting results showed that miR-322 suppressed celf1 protein expression. Furthermore, Western blotting, RT-PCR, and immunofluorescence results showed that celf1 may inhibit ESCs' differentiation toward cardiomyocytes in vitro. Overall, the results indicate that miR-322 might promote ESCs' differentiation toward cardiomyocytes by regulating celf1 expression.

Circulating microRNA: Myocardium-derived prenatal biomarker of ventricular septal defects

Background: Recently, circulating microRNAs (miRNAs) from maternal blood and amniotic fluid have been used as biomarkers for ventricular septal defect (VSD) diagnosis. However, whether circulating miRNAs are associated with fetal myocardium remains unknown.

Methods: Dimethadione (DMO) induced a VSD rat model. The miRNA expression profiles of the myocardium, amniotic fluid and maternal serum were analyzed. Differentially expressed microRNAs (DE-microRNAs) were verified by qRT–PCR. The target gene of miR-1-3p was confirmed by dual luciferase reporter assays. Expression of amniotic fluid-derived DE-microRNAs was verified in clinical samples.

Results: MiRNAs were differentially expressed in VSD fetal rats and might be involved in cardiomyocyte differentiation and apoptosis. MiR-1-3p, miR-1b and miR-293-5p were downregulated in the myocardium and upregulated in amniotic fluid/maternal serum. The expression of amniotic fluid-derived DE-microRNAs (miR-1-3p, miR-206 and miR-184) was verified in clinical samples. Dual luciferase reporter assays confirmed that miR-1-3p directly targeted SLC8A1/NCX1.

Conclusion: MiR-1-3p, miR-1b and miR-293-5p are downregulated in VSD myocardium and upregulated in circulation and may be released into circulation by cardiomyocytes. MiR-1-3p targets SLC8A1/NCX1 and participates in myocardial apoptosis. MiR-1-3p upregulation in circulation is a direct and powerful indicator of fetal VSD and is expected to serve as a prenatal VSD diagnostic marker.

Stabilization of SETD3 by deubiquitinase USP27 enhances cell proliferation and hepatocellular carcinoma progression

The histone methyltransferase SETD3 plays critical roles in various biological events, and its dysregulation is often associated with human diseases including cancer. However, the underlying regulatory mechanism remains elusive. Here, we reported that ubiquitin-specific peptidase 27 (USP27) promotes tumor cell growth by specifically interacting with SETD3, negatively regulating its ubiquitination, and enhancing its stability. Inhibition of USP27 expression led to the downregulation of SETD3 protein level, the blockade of the cell proliferation and tumorigenesis of hepatocellular carcinoma (HCC) cells. In addition, we found that USP27 and SETD3 expression is positively correlated in HCC tissues. Notably, higher expression of USP27 and SETD3 predicts a worse survival in HCC patients. Collectively, these data elucidated that a USP27-dependent mechanism controls SETD3 protein levels and facilitates its oncogenic role in liver tumorigenesis.

Up-regulation of SETD3 may contribute to post-stroke depression in rat through negatively regulating VEGF expression

Post-stroke depression (PSD) is one of the most familiar complications of stroke, which refers to stroke patients who have varying degrees of depression (lasts for >2 weeks). SET domain-containing 3 (SETD3) is a conserved histone H3 methyltransferase, and the role of SETD3 in some diseases is increasingly being explored. However, the effects of SETD3 in PSD remain unclear. In this study, the PSD rat model was firstly constructed by Endothelin-1 injection combined with chronic unpredictable mild stress, and we discovered that SETD3 expression was up-regulated in PSD rat model. Additionally, SETD3 knockdown relieved the depressive symptom of PSD. Moreover, SETD3 knockdown promoted proliferation and differentiation of neural stem cells (NSCs). Due to the critical role of vascular endothelial growth factor (VEGF) in antidepressant and SETD3 can negatively regulate VEGF, we speculated that SETD3 may regulate PSD progression through VEGF. Our results demonstrated that SETD3 knockdown up-regulated VEGF expression. Furthermore, SETD3 modulated the proliferation and differentiation of NSCs through regulating VEGF expression. In conclusion, our study indicated that up-regulation of SETD3 contributed to PSD progression in rats through negatively regulating VEGF expression. The findings of this work suggest that SETD3 may be a promising target for treating PSD in the future.

Evaluation of muscle-specific and metabolism regulating microRNAs in a chronic swimming rat model

Making benefit from the epigenetic effects of environmental factors such as physical activity may result in a considerable improvement in the prevention of chronic civilization diseases. In our chronic swimming rat model, the expression levels of such microRNAs were characterized, that are involved in skeletal muscle differentiation, hypertrophy and fine-tuning of metabolism, which processes are influenced by chronic endurance training, contributing to the metabolic adaptation of skeletal muscle during physical activity. After chronic swimming, the level of miR-128a increased significantly in EDL muscles, which may influence metabolic adaptation and stress response as well. In SOL, the expression level of miR-15b and miR-451 decreased significantly after chronic swimming, which changes are opposite to their previously described increment in insulin resistant skeletal muscle. MiR-451 also targets PGC-1α mRNA, whiches expression level significantly increased in SOL muscles, resulting in enhanced biogenesis and oxidative capacity of mitochondria. In summary, the microRNA expression changes that were observed during our experiments suggest that chronic swim training contributes to a beneficial metabolic profile of skeletal muscle.

In Utero Fetal Weight in Pigs Is Regulated by microRNAs and Their Target Genes

Impaired skeletal muscle growth in utero can result in reduced birth weight and poor carcass quality in pigs. Recently, we showed the role of microRNAs (miRNAs) and their target genes in prenatal skeletal muscle development and pathogenesis of intrauterine growth restriction (IUGR). In this study, we performed an integrative miRNA-mRNA transcriptomic analysis in longissimus dorsi muscle (LDM) of pig fetuses at 63 days post conception (dpc) to identify miRNAs and genes correlated to fetal weight. We found 13 miRNAs in LDM significantly correlated to fetal weight, including miR-140, miR-186, miR-101, miR-15, miR-24, miR-29, miR-449, miR-27, miR-142, miR-99, miR-181, miR-199, and miR-210. The expression of these miRNAs decreased with an increase in fetal weight. We also identified 1315 genes significantly correlated to fetal weight at 63 dpc, of which 135 genes were negatively correlated as well as identified as potential targets of the above-listed 13 miRNAs. These miRNAs and their target genes enriched pathways and biological processes important for fetal growth, development, and metabolism. These results indicate that the transcriptomic profile of skeletal muscle can be used to predict fetal weight, and miRNAs correlated to fetal weight can serve as potential biomarkers of prenatal fetal health and growth.

Upregulation of PAIP1 promotes the gallbladder tumorigenesis through regulating PLK1 level

Background

Increasing evidence suggests that elevated expression of polyA-binding protein-interacting protein 1 (PAIP1) is associated with cancer development and progression. However, how PAIP1 promotes gallbladder cancer (GBC) is still unclear.

Methods

Two GBC tissue-derived cell lines, NOZ and GBC-SD cells, were used in this study. Assays of cell proliferation, colony formation, apoptosis, and xenograft tumor model were performed to examine the tumorigenic effects of PAIP1. Immunohistochemical (IHC) staining was used to examine the expression level of PAIP1 in both patient GBC tissues and mouse tumors. Microarray and bioinformatics analysis were used to explore the targets of PAIP1. Quantitative polymerase chain reaction (qPCR) and western blot analysis were used to validate PAIP1-mediated targets.

Results

We found that upregulated PAIP1 expression was correlated with GBC. Knockdown of PAIP1 in gallbladder cells alleviated cell proliferation, promoted apoptosis, and inhibited xenograft tumor growth. Gene microarray analysis showed that stable silencing of PAIP1 altered various gene expressions. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested that PAIP1 regulates cell cycle progression. Finally, we found that the PLK1 kinase, a key regulator of cell cycle, was regulated by PAIP1 at the transcriptional and protein levels. PLK1 level was positively correlated with PAIP1 level in both mouse tumors and GBC tissues. PAIP1 interacted with PLK1, and rescue of PAIP1 could recover PLK1 protein level and inhibit apoptosis.

Conclusions

Our data suggest that PAIP1 contributes to GBC progression likely through regulating PLK1 level. Since upregulated PAIP1 expression is positively associated with GBC, PAIP1 may act as a clinical prognostic biomarker of GBC.

miR-322/miR-503 clusters regulate defective myoblast differentiation in myotonic dystrophy RNA-toxic by targeting Celf1

Myotonic dystrophy (DM) is a genetic disorder featured by muscular dystrophy. It is caused by CUG expansion in the myotonic dystrophy protein kinase gene that leads to aberrant signaling and impaired myocyte differentiation. Many studies have shown that microRNAs are involved in the differentiation process of myoblasts. The purpose of this study was to investigate how the miR-322/miR-503 cluster regulates intracellular signaling to affect cell differentiation. The cell model of DM1 was employed by expressing GFP-CUG200 or CUGBP Elav-like family member 1 (Celf1) in myoblasts. Immunostaining of MF-20 was performed to examine myocyte differentiation. qRT-PCR and western blot were used to determine the levels of Celf1, MyoD, MyoG, Mef2c, miR-322/miR-503, and mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) signaling. Dual luciferase assay was performed to validate the interaction between miR-322/miR-503 and Celf1. CUG expansion in myoblasts impaired the cell differentiation, increased the Celf1 level, but it decreased the miR-322/miR-503 levels. miR-322/miR-503 mimics restored the impaired differentiation caused by CUG expansion, while miR-322/miR-503 inhibitors further suppressed. miR-322/miR-503 directly targeted Celf1 and negatively regulated its expression. Knockdown of Celf1 promoted myocyte differentiation. Further, miR-322/miR-503 mimics rescued the impaired differentiation of myocytes caused by CUG expansion or Celf1 overexpression through suppressing of MEK/ERK signaling. miR-322/miR-503 cluster recover the defective myocyte differentiation caused by RNA-toxic via targeting Celf1. Restoring miR-322/miR-503 levels could be an avenue for DM1 therapy.

Bone and Muscle Crosstalk in Aging

Osteoporosis and sarcopenia are two age-related diseases that affect the quality of life in the elderly. Initially, they were thought to be two independent diseases; however, recently, increasing basic and clinical data suggest that skeletal muscle and bone are both spatially and metabolically connected. The term "osteosarcopenia" is used to define a condition of synergy of low bone mineral density with muscle atrophy and hypofunction. Bone and muscle cells secrete several factors, such as cytokines, myokines, and osteokines, into the circulation to influence the biological and pathological activities in local and distant organs and cells. Recent studies reveal that extracellular vesicles containing microRNAs derived from senescent skeletal muscle and bone cells can also be transported and aid in regulating bone-muscle crosstalk. In this review, we summarize the age-related changes in the secretome and extracellular vesicle-microRNAs secreted by the muscle and bone, and discuss their interactions between muscle and bone cells during aging.

The methyltransferase SETD3-mediated histidine methylation: Biological functions and potential implications in cancers

SETD3 belongs to a family of SET-domain containing proteins. Recently, SETD3 was found as the first and so-far the only known metazoan histidine methyltransferase that catalyzes actin histidine 73 (His73) methylation, a pervasive modification which was discovered more than 50 years ago. In this review, we summarize some recent advances in SETD3 research, focusing on structural properties, substrate-recognition features, and physiological functions. We particularly highlight potential pathological relevance of SETD3 in human cancers and raise some questions to promote discussion about this novel histidine methyltransferase.

miR-322/-503 rescues myoblast defects in myotonic dystrophy type 1 cell model by targeting CUG repeats

Myotonic dystrophy type 1 (DM1) is the most common type of adult muscular dystrophy caused by the expanded triple-nucleotides (CUG) repeats. Myoblast in DM1 displayed many defects, including defective myoblast differentiation, ribonuclear foci, and aberrant alternative splicing. Despite many were revealed to function in DM1, microRNAs that regulated DM1 via directly targeting the expanded CUG repeats were rarely reported. Here we discovered that miR-322/-503 rescued myoblast defects in DM1 cell model by targeting the expanded CUG repeats. First, we studied the function of miR-322/-503 in normal C2C12 myoblast cells. Downregulation of miR-322/-503 significantly hindered the myoblast differentiation, while miR-322/-503 overexpression promoted the process. Next, we examined the role of miR-322/-503 in the DM1 C2C12 cell model. miR-322/-503 was downregulated in the differentiation of DM1 C2C12 cells. When we introduced ectopic miR-322/-503 expression into DM1 C2C12 cells, myoblast defects were almost fully rescued, marked by significant improvements of myoblast differentiation and repressions of ribonuclear foci formation and aberrant alternative splicing. Then we investigated the downstream mechanism of miR-322/-503 in DM1. Agreeing with our previous work, Celf1 was proven to be miR-322/-503′s target. Celf1 knockdown partially reproduced miR-322/-503′s function in rescuing DM1 C2C12 differentiation but was unable to repress ribonuclear foci, suggesting other targets of miR-322/-503 existed in the DM1 C2C12 cells. As the seed regions of miR-322 and miR-503 were complementary to the CUG repeats, we hypothesized that the CUG repeats were the target of miR-322/-503. Through expression tests, reporter assays, and colocalization staining, miR-322/-503 was proved to directly and specifically target the expanded CUG repeats in the DM1 cell model rather than the shorter ones in normal cells. Those results implied a potential therapeutic function of miR-322/-503 on DM1, which needed further investigations in the future.

Ablation of the miRNA Cluster 24 Has Profound Effects on Extracellular Matrix Protein Abundance in Cartilage

MicroRNAs (miRNAs) regulate cartilage differentiation and contribute to the onset and progression of joint degeneration. These small RNA molecules may affect extracellular matrix organization (ECM) in cartilage, but for only a few miRNAs has this role been defined in vivo. Previously, we showed that cartilage-specific genetic ablation of the Mirc24 cluster in mice leads to impaired cartilage development due to increased RAF/MEK/ERK pathway activation. Here, we studied the expression of the cluster in cartilage by LacZ reporter gene assays and determined its role for extracellular matrix homeostasis by proteome and immunoblot analysis. The cluster is expressed in prehypertrophic/hypertrophic chondrocytes of the growth plate and we now show that the cluster is also highly expressed in articular cartilage. Cartilage-specific loss of the cluster leads to increased proteoglycan 4 and matrix metallopeptidase 13 levels and decreased aggrecan and collagen X levels in epiphyseal cartilage. Interestingly, these changes are linked to a decrease in SRY-related HMG box-containing (SOX) transcription factors 6 and 9, which regulate ECM production in chondrocytes. Our data suggests that the Mirc24 cluster is important for ECM homoeostasis and the expression of transcriptional regulators of matrix production in cartilage.

MicroRNAs as potential therapeutic targets for muscle wasting during cancer cachexia

PURPOSE OF REVIEW

Muscle wasting in cancer cachexia remains an unmet clinical need due to lack of effective therapies associated with the complexity of the disease. Here, we discuss microRNAs, robust regulators of the expression of multiple genes, only recently characterized in cancer cachexia in humans and their therapeutic potential for muscle wasting.

RECENT FINDINGS

Changes in microRNAs in muscle of cancer patients have been demonstrated for the first time and these are associated with dysregulated signalling networks during muscle wasting. These data, together with studies in animal models, indicate that microRNAs are attractive therapeutic candidates for maintaining muscle mass, both during and following cancer treatment ultimately improving patient outcomes.

SUMMARY

Cancer cachexia is a complex metabolic condition associated with muscle wasting. Maintenance of muscle mass in cancer patients can improve their response to therapy and prognosis. microRNAs, which can act as oncogenes or tumour suppressors, are also dysregulated in muscle of cachexia patients. Studies in animal models of muscle wasting have demonstrated that microRNAs regulate muscle mass and strength. With more microRNA-based therapeutics in clinical trials and first RNA drugs approved, microRNAs present an attractive novel therapeutic avenue for maintaining muscle homeostasis in cachexia patients to improve their prognosis.

Altered miRNA and mRNA Expression in Sika Deer Skeletal Muscle with Age

Studies of the gene and miRNA expression profiles associated with the postnatal late growth, development, and aging of skeletal muscle are lacking in sika deer. To understand the molecular mechanisms of the growth and development of sika deer skeletal muscle, we used de novo RNA sequencing (RNA-seq) and microRNA sequencing (miRNA-seq) analyses to determine the differentially expressed (DE) unigenes and miRNAs from skeletal muscle tissues at 1, 3, 5, and 10 years in sika deer. A total of 51,716 unigenes, 171 known miRNAs, and 60 novel miRNAs were identified based on four mRNA and small RNA libraries. A total of 2,044 unigenes and 11 miRNAs were differentially expressed between adolescence and juvenile sika deer, 1,946 unigenes and 4 miRNAs were differentially expressed between adult and adolescent sika deer, and 2,209 unigenes and 1 miRNAs were differentially expressed between aged and adult sika deer. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that DE unigenes and miRNA were mainly related to energy and substance metabolism, processes that are closely associate with the growth, development, and aging of skeletal muscle. We also constructed mRNA–mRNA and miRNA–mRNA interaction networks related to the growth, development, and aging of skeletal muscle. The results show that mRNA (Myh1, Myh2, Myh7, ACTN3, etc.) and miRNAs (miR-133a, miR-133c, miR-192, miR-151-3p, etc.) may play important roles in muscle growth and development, and mRNA (WWP1, DEK, UCP3, FUS, etc.) and miRNAs (miR-17-5p, miR-378b, miR-199a-5p, miR-7, etc.) may have key roles in muscle aging. In this study, we determined the dynamic miRNA and unigenes transcriptome in muscle tissue for the first time in sika deer. The age-dependent miRNAs and unigenes identified will offer insights into the molecular mechanism underlying muscle development, growth, and maintenance and will also provide valuable information for sika deer genetic breeding.

Fetal malnutrition-induced catch up failure is caused by elevated levels of miR-322 in rats

If sufficient nutrition is not obtained during pregnancy, the fetus changes its endocrine system and metabolism to protect the brain, resulting in a loss of body size. The detailed mechanisms that determine the success or failure of growth catch-up are still unknown. Therefore, we investigated the mechanism by which catch-up growth failure occurs. The body weights of rat pups at birth from dams whose calorie intake during pregnancy was reduced by 40% were significantly lower than those of controls, and some offspring failed to catch up. Short-body-length and low-bodyweight rats showed blood IGF-1 levels and mRNA expression levels of IGF-1 and growth hormone receptor (GHR) in the liver that were lower than those in controls. The next generation offspring from low-bodyweight non-catch-up (LBW-NCG) rats had high expression of miR-322 and low expression of GHR and IGF-1. The expression of miR-322 showed a significant negative correlation with GHR expression and body length, and overexpression of miR-322 suppressed GHR expression. We found that insufficient intake of calories during pregnancy causes catch-up growth failure due to increased expression of miR-322 and decreased expression of GHR in the livers of offspring, and this effect is inherited by the next generation.

MicroRNA-30-3p Suppresses Inflammatory Factor-Induced Endothelial Cell Injury by Targeting TCF21

Atherosclerosis is one of the leading causes of mortality worldwide. Growing evidence suggested that miRNAs contributed to the progression of atherosclerosis. miR-30-5p was found involved in various diseases. However, the role of miR-30-5p in regulation of atherosclerosis is not known. Here, we aim to investigate the effects of miR-30-5p on regulating the progression of atherosclerosis. The expression levels of miR-30-5p in serum collected from atherosclerosis patients and normal healthy people were analyzed by qRT-PCR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway bioinformatics were carried out to reveal the possible signaling pathways involved in the mode of action of miR-30-5p. A potential target gene of miRNA-30-5p was searched and examined by a luciferase reporter assay. ELISA, Western blot, proliferation, and flow cytometry assays were performed to assess the biological functional role of miR-30-5p in vitro. Also, an in vitro monocyte-endothelial cell coculture model was used to study the functional role of miR-30-5p in atherosclerosis. We found that miR-30-5p was significantly decreased in serum samples from atherosclerosis patients compared with control subjects. GO and KEGG analysis results showed that miR-30-5p is highly associated with genetic profile of cardiovascular disease. TCF21 was verified as a target gene of miR-30-5p. Overexpression of miR-30-5p in THP-1 not only protected endothelial cell viability but also inhibited endothelial cell apoptosis, and similar results were observed in cells with that of TCF21 knocked down. Moreover, miR-30-5p decreased the expression levels of lactate dehydrogenase (LDH) and tumor necrosis factor-α (TNF-α) and reduced reactive oxygen species (ROS) accumulation. NF-κB and MAPK/p38 pathways played an indispensable role in the protection ability of miR-30-5p against atherosclerosis. Our results reveal that miR-30-5p suppresses the progression of atherosclerosis through targeting TCF21 in vitro. Therefore, the miR-30-5p-TCF21-MAPK/p38 signaling pathway may be a potential biomarker or therapeutic target in atherosclerosis.