MicroRNA 429 Regulates Mucin Gene Expression and Secretion in Murine Model of Colitis

MicroRNA 429 regulates MMPs expression by modulating TIMP2 expression in colon cancer cells and inflammatory colitis

BACKGROUND

In a previous study, we found that the expression of microRNA 429 (MIR429) was decreased in dextran sodium sulfate (DSS)-induced mouse colitis tissues.

OBJECTIVE

In this study, we aimed to investigate the interaction of MIR429 with TIMP metallopeptidase inhibitor 2 (TIMP2), one of its candidate target genes, in human colorectal cancer (CRC) cells and DSS-induced mouse colitis tissues.

METHODS

A luciferase reporter system was used to confirm the effect of MIR429 on TIMP2 expression. The expression levels of MIR429 and target genes in cells or tissues were evaluated through quantitative RT-PCR, western blotting, or immunohistochemistry.

RESULTS

We found that the expression level of MIR429 was downregulated in human CRC tissues, and also showed that TIMP2 is a direct target gene of MIR429 in CRC cell lines. Furthermore, MIR429 regulate TIMP2-mediated matrix metallopeptidases (MMPs) expression in CRC cells. We also generated cell lines stably expressing MIR429 in CRC cell lines and showed that MIR429 regulates the expression of MMPs by mediating TIMP2 expression. In addition to human CRC tissues, we found that TIMP2 was highly expressed in mouse colitis tissues and human ulcerative colitis (UC) tissues.

CONCLUSIONS

Our findings suggest that the expression of endogenous MIR429 was reduced in human CRC tissues and colitis, leading to upregulation of its target gene TIMP2. The upregulation of TIMP2 by decreased MIR429 expression in CRC tissues and inflamed tissues suggests that it may affect extracellular matrix (ECM) remodeling through downregulation of MMPs. Therefore, MIR429 may have therapeutic value for human CRC and colitis.

Emerging role of microRNAs as regulators of protein kinase C substrate MARCKS and MARCKSL1 in cancer

MicroRNAs (miRNAs) have emerged as pivotal regulators of gene expression, playing essential roles in diverse cellular processes, including the development and progression of cancer. Among the numerous proteins influenced by miRNAs, the MARCKS/MARCKSL1 protein, a key regulator of cellular cytoskeletal dynamics and membrane-cytosol communication, has garnered significant attention due to its multifaceted involvement in various cancer-related processes, including cell migration, invasion, metastasis, and drug resistance. Motivated by the encouraging early clinical success of peptides targeting MARCKS in several pathological conditions, this review article delves into the intricate interplay between miRNAs and the MARCKS protein in cancer. Herein, we have highlighted the latest findings on specific miRNAs that modulate MARCKS/MARCKSL1 expression, providing a comprehensive overview of their roles in different cancer types. We have underscored the need for in-depth investigations into the therapeutic feasibility of targeting the miRNA-MARCKS axis in cancer, taking cues from the successes witnessed in related fields. Unlocking the full potential of miRNA-mediated MARCKS regulation could pave the way for innovative and effective therapeutic interventions against various cancer types.

MicroRNA-200 Loaded Lipid Nanoparticles Promote Intestinal Epithelium Regeneration in Canonical MicroRNA-Deficient Mice

Intestinal epithelium undergoes regeneration after injuries, and the disruption of this process can lead to inflammatory bowel disease and tumorigenesis. Intestinal stem cells (ISCs) residing in the crypts are crucial for maintaining the intestinal epithelium's homeostasis and promoting regeneration upon injury. However, the precise role of DGCR8, a critical component in microRNA (miRNA) biogenesis, in intestinal regeneration remains poorly understood. In this study, we provide compelling evidence demonstrating the indispensable role of epithelial miRNAs in the regeneration of the intestine in mice subjected to 5-FU or irradiation-induced injury. Through a comprehensive pooled screen of miRNA function in Dgcr8-deficient organoids, we observe that the loss of the miR-200 family leads to the hyperactivation of the p53 pathway, thereby reducing ISCs and impairing epithelial regeneration. Notably, downregulation of the miR-200 family and hyperactivation of the p53 pathway are verified in colonic tissues from patients with active ulcerative colitis (UC). Most importantly, the transient supply of miR-200 through the oral delivery of lipid nanoparticles (LNPs) carrying miR-200 restores ISCs and promotes intestinal regeneration in mice following acute injury. Our study implies the miR-200/p53 pathway as a promising therapeutic target for active UC patients with diminished levels of the miR-200 family. Furthermore, our findings suggest that the clinical application of LNP-miRNAs could enhance the efficacy, safety, and acceptability of existing therapeutic modalities for intestinal diseases.

MicroRNA 452 regulates SHC1 expression in human colorectal cancer and colitis

BACKGROUND

Human microRNA 452 (MIR452) has been linked to both colorectal cancer (CRC) tissues and dextran sulfate sodium (DSS)-induced colitis.

OBJECTIVE

We analyzed the correlation between MIR452 and its putative target gene in human CRC cells and in mouse colitis tissues.

METHODS

Luciferase reporter assay confirmed that Src homologous and collagen adaptor protein 1 (SHC1) is a direct target of MIR452. Furthermore, the expression of proteins or mRNA was assessed by immunohistochemical analysis, Western blot, or quantitative RT-PCR (qRT-PCR).

RESULTS

We found that MIR452 has a potential binding site at 3'-UTR of SHC1. Likewise, MIR452 or siSHC1 transfection dramatically reduced the level of cellular SHC1 in CRC cells. The expression of SHC1 was frequently downregulated in both human CRC tissues and mouse colitis tissues. In CRC cells, we demonstrated that MIR452 regulated the expression of genes involved in the SHC1-mediated KRAS-MAPK signal transduction pathways.

CONCLUSION

These findings suggest a potential defense mechanism in which MIR452 regulation of the adaptor protein SHC1 maintains cellular homeostasis during carcinogenesis or chronic inflammation. Therefore, MIR452 may have therapeutic value for human early-stage CRC and colitis.

A comprehensive review on RNA interference-mediated targeting of interleukins and its potential therapeutic implications in colon cancer

Colon cancer is the world's fourth leading cause of death. It is cancer of the latter part of the large intestine, i.e. the colon. Chronic inflammation over a long period also leads to the development of cancer. Cancer in the colon region is arduous to diagnose and is detected at a later stage when it metastasizes to other parts of the body like the liver, lungs, peritoneum, etc. Colon cancer is a great example of solid tumours associated with chronic inflammation. Although conventional therapies are effective, they lose their effectiveness beyond a certain point. Relapse of the disease occurs frequently. RNA interference (RNAi) is emerging as a great tool to specifically attack the cancer cells of a target site like the colon. RNAi deals with epigenetic changes made in the defective cells which ultimately leads to their death without harming the healthy cells. In this review, two types of epigenetic modulators have been considered, namely siRNA and miRNA, and their effect on interleukins. Interleukins, a class of cytokines, are major inflammatory responses of the body that are released by immune cells like leukocytes and macrophages. Some of these interleukins are pro-inflammatory, thereby promoting inflammation which eventually causes cancer. RNAi can prevent colon cancer by inhibiting pro-inflammatory interleukins.

miRNA effects on gut homeostasis: therapeutic implications for inflammatory bowel disease

Inflammatory bowel disease (IBD) spans a range of chronic conditions affecting the gastrointestinal (GI) tract, which are marked by intermittent flare-ups and remissions. IBD results from microbial dysbiosis or a defective mucosal barrier in the gut that triggers an inappropriate immune response in a genetically susceptible person, altering the immune-microbiome axis. In this review, we discuss the regulatory roles of miRNAs, small noncoding RNAs with gene regulatory functions, in the stability and maintenance of the gut immune-microbiome axis, and detail the challenges and recent advances in the use of miRNAs as putative therapeutic agents for treating IBD.

Construction of ceRNA Network to Reveal Potential Biomarkers in Crohn's Disease and Validation in a TNBS Induced Mice Model

Purpose

We aimed to construct a competing endogenous RNA (ceRNA) network and explore the potential biomarkers in Crohn's disease (CD) via bioinformatics analysis. Validation of candidate biomarkers in a 2,4,6-trinitrobenzene sulfonic acid (TNBS) induced experimental colitis model and ceRNA network in an HCT116 cell line was also an aim, along with purposing to reveal the pathogenesis of CD.

Methods

GSE102134 and GSE67106 datasets were obtained and used to screen the differentially expressed genes. WCGNA was applied to identify the relative model to construct the ceRNA network. Furthermore, the relationship between candidate gene and immune infiltration was investigated. Then, the expression of potential biomarkers was validated via qRT-PCR in a TNBS induced experimental colitis model. Finally, the ceRNA network was confirmed by RNAi experiments in an HCT116 cell line.

Results

The ceRNA network, consisting of four lncRNAs, four miRNAs, and eight mRNAs, was constructed and the ROC analysis showed four mRNAs (PTGS2, LPL, STAT1, and TRIB2) had high diagnostic accuracy (AUC>0.9). In addition, upregulated PTGS2 was positively correlated with immune cell infiltration, including Natural killer cells, exhausted T-cells, monocytes, and Dendritic cells. The outcome of this TNBS induced experimental colitis model verified that the expression of PTGS2 and mir-429 was consistent with results of previous bioinformatics analysis. Furthermore, the predicted ceRNA network MIR3142HG/mir-429/PTGS2 were validated via RNA interference. Knockout of MIR3142HG decreased the mRNA level of PTGS2, whereas inhibition of mir-429 increased the mRNA level of PTGS2 in the HCT116 cell line.

Conclusion

The exploration of the ceRNA network in this work might contribute to understanding the pathogenesis of CD. The constructed MIR3142HG/mir-429/PTGS2 ceRNA network may play a role in CD, and PTGS2 can be a potential immune-related biomarker in CD.

MicroRNAs expression influence in ulcerative colitis and Crohn's disease: A pilot study for the identification of diagnostic biomarkers

BACKGROUND

Inflammatory bowel disease (IBD) comprises two distinct diseases, Crohn’s disease (CD) and ulcerative colitis (UC), both of which are chronic, relapsing inflammatory disorders of the gastrointestinal tract with a mostly unknown etiology. The incidence and prevalence of IBD are continually increasing, indicating the need for further studies to investigate the genetic determinants of these diseases. Since microRNAs (miRNAs) regulate protein translation via complementary binding to mRNA, discovering differentially expressed miRNAs (DE) in UC or CD patients could be important for diagnostic biomarker identification, assisting in the appropriate disease differentiation progressing the understanding of IBD pathogenesis.

AIM

To determine the miRNA expression profile in UC and CD patients and the potential pathophysiological contributions of differentially expressed miRNA.

METHODS

A total of 20 formalin-fixed paraffin-embedded colonic samples were collected from the Pathology Department of Botucatu Medical School at São Paulo State University (Unesp). The diagnosis of UC or CD was based on clinical, endoscopic, radiologic, and histological criteria and confirmed by histopathological analysis at the time of selection. The TaqMan™ Array Human MicroRNA A+B Cards Set v3.0 (Applied Biosystems™) platform was used to analyze 754 miRNAs. Targets of DE-miRNAs were predicted using miRNA Data Integration Portal (mirDIP) and the miRNA Target Interaction database (MiRTarBase). All statistical analyses were conducted using GraphPad Prism software. Parametric and nonparametric data were analyzed using t-tests and Mann-Whitney U tests, respectively.

RESULTS

The results showed that of the 754 miRNAs that were initially evaluated, 643 miRNAs were found to be expressed in at least five of the patients who were diagnosed with either CD or UC; the remaining 111 miRNAs were not considered to be expressed in these patients. The expression levels of 28 miRNAs were significantly different between the CD and UC patients (P ≤ 0.05); 13 miRNAs demonstrated a fold-change in expression level greater than 1. Five miRNAs with a downregulated expression were selected for enrichment analysis. The miRNAs whose expression levels were significantly lower in UC patients than in CD patients were enriched in certain signaling pathways that were mostly correlated with cancer-related processes and respective biomarkers.

CONCLUSION

MiRNAs could be used to differentiate UC from CD, and differently expressed miRNAs could help explain the distinct pathophysiology of each disease.

The Impact of MicroRNAs during Inflammatory Bowel Disease: Effects on the Mucus Layer and Intercellular Junctions for Gut Permeability

Research on inflammatory bowel disease (IBD) has produced mounting evidence for the modulation of microRNAs (miRNAs) during pathogenesis. MiRNAs are small, non-coding RNAs that interfere with the translation of mRNAs. Their high stability in free circulation at various regions of the body allows researchers to utilise miRNAs as biomarkers and as a focus for potential treatments of IBD. Yet, their distinct regulatory roles at the gut epithelial barrier remain elusive due to the fact that there are several external and cellular factors contributing to gut permeability. This review focuses on how miRNAs may compromise two components of the gut epithelium that together form the initial physical barrier: the mucus layer and the intercellular epithelial junctions. Here, we summarise the impact of miRNAs on goblet cell secretion and mucin structure, along with the proper function of various junctional proteins involved in paracellular transport, cell adhesion and communication. Knowledge of how this elaborate network of cells at the gut epithelial barrier becomes compromised as a result of dysregulated miRNA expression, thereby contributing to the development of IBD, will support the generation of miRNA-associated biomarker panels and therapeutic strategies that detect and ameliorate gut permeability.

Transcriptomic Characterization of Cow, Donkey and Goat Milk Extracellular Vesicles Reveals Their Anti-Inflammatory and Immunomodulatory Potential

Milk extracellular vesicles (mEVs) seem to be one of the main maternal messages delivery systems. Extracellular vesicles (EVs) are micro/nano-sized membrane-bound structures enclosing signaling molecules and thus acting as signal mediators between distant cells and/or tissues, exerting biological effects such as immune modulation and pro-regenerative activity. Milk is also a unique, scalable, and reliable source of EVs. Our aim was to characterize the RNA content of cow, donkey, and goat mEVs through transcriptomic analysis of mRNA and small RNA libraries. Over 10,000 transcripts and 2000 small RNAs were expressed in mEVs of each species. Among the most represented transcripts, 110 mRNAs were common between the species with cow acting as the most divergent. The most represented small RNA class was miRNA in all the species, with 10 shared miRNAs having high impact on the immune regulatory function. Functional analysis for the most abundant mRNAs shows epigenetic functions such as histone modification, telomere maintenance, and chromatin remodeling for cow; lipid catabolism, oxidative stress, and vitamin metabolism for donkey; and terms related to chemokine receptor interaction, leukocytes migration, and transcriptional regulation in response to stress for goat. For miRNA targets, shared terms emerged as the main functions for all the species: immunity modulation, protein synthesis, cellular cycle regulation, transmembrane exchanges, and ion channels. Moreover, donkey and goat showed additional terms related to epigenetic modification and DNA maintenance. Our results showed a potential mEVs immune regulatory purpose through their RNA cargo, although in vivo validation studies are necessary.

The myristoylated alanine-rich C-kinase substrates (MARCKS): A membrane-anchored mediator of the cell function

The myristoylated alanine-rich C-kinase substrate (MARCKS) and the MARCKS-related protein (MARCKSL1) are ubiquitous, highly conserved membrane-associated proteins involved in the structural modulation of the actin cytoskeleton, chemotaxis, motility, cell adhesion, phagocytosis, and exocytosis. MARCKS includes an N-terminal myristoylated domain for membrane binding, a highly conserved MARCKS Homology 2 (MH2) domain, and an effector domain (which is the phosphorylation site). MARCKS can sequester phosphatidylinositol-4, 5-diphosphate (PIP2) at lipid rafts in the plasma membrane of quiescent cells, an action reversed by protein kinase C (PKC), ultimately modulating the immune function. Being expressed mostly in innate immune cells, MARCKS promotes the inflammation-driven migration and adhesion of cells and the secretion of cytokines such as tumor necrosis factor (TNF). From a clinical point of view, MARCKS is overexpressed in patients with schizophrenia and bipolar disorders, while the brain level of MARCKS phosphorylation is associated with Alzheimer's disease. Furthermore, MARCKS is associated with the development and progression of numerous types of cancers. Data in autoimmune diseases are limited to rheumatoid arthritis models in which a connection between MARCKS and the JAK-STAT pathway is mediated by miRNAs. We provide a comprehensive overview of the structure of MARCKS, its molecular characteristics and functions from a biological and pathogenetic standpoint, and will discuss the clinical implications of this pathway.

MicroRNA 452 regulates IL20RA-mediated JAK1/STAT3 pathway in inflammatory colitis and colorectal cancer

OBJECTIVE

MicroRNAs are a class of small, non-coding RNAs that play a key role in several biological and molecular processes, including tumorigenesis. We previously identified that MIR452 is upregulated in both colorectal cancer (CRC) and colitis. However, the functional mechanisms of MIR452 and its target genes in CRC and colitis are not well understood. So, we hypothesize that MIR452 can influence CRC and DSS-induced colitis model through the regulation of IL20RA and its downstream JAK-STATs signaling pathway.

METHODS

We used a luciferase reporter assay to confirm the effect of MIR452 on IL20RA expression. The protein and mRNA expression of a target gene and its associated molecules were measured by western blot, quantitative RT-PCR, and immunohistochemistry.

RESULTS

We found that the IL20RA was a direct target gene of MIR452. Overexpression of MIR452 in CRC cell lines significantly decreased IL20RA and its downstream Janus kinase 1 (JAK1), Signal transducer and activator of transcription 1 (STAT1) and STAT3. Knockdown of IL20RA in CRC cell lines by IL20RA gene silencing also decreased the expression of IL20RA, JAK1, and STAT3, but not of STAT1.

CONCLUSION

Our results suggest that MIR452 regulates STAT3 through the IL20RA-mediated JAK1 pathway, but not STAT1. Overall, MIR452 acts as tumor suppressor in human CRC and in a mouse colitis model. These findings suggest that MIR452 is a promising therapeutic target in the treatment of cancer and colitis.

Role of Goblet Cells in Intestinal Barrier and Mucosal Immunity

Goblet cells and the mucus they secrete serve as an important barrier, preventing pathogens from invading the mucosa to cause intestinal inflammation. The perspective regarding goblet cells and mucus has changed, with current evidence suggesting that they are not passive but play a positive role in maintaining intestinal tract immunity and mucosal homeostasis. Goblet cells could obtain luminal antigens, presenting them to the underlying antigen-presenting cells (APCs) that induces adaptive immune responses. Various immunomodulatory factors can promote the differentiation and maturation of goblet cells, and the secretion of mucin. The abnormal proliferation and differentiation of goblet cells, as well as the deficiency synthesis and secretion of mucins, result in intestinal mucosal barrier dysfunction. This review provides an extensive outline of the signaling pathways that regulate goblet cell proliferation and differentiation and control mucins synthesis and secretion to elucidate how altering these pathways affects goblet functionality. Furthermore, the interaction between mucins and goblet cells in intestinal mucosal immunology is described. Therefore, the contribution of goblet cells and mucus in promoting gut defense and homeostasis is illustrated, while clarifying the regulatory mechanisms involved may allow the development of new therapeutic strategies for intestinal disorders.

Clinical significance of a microRNA signature for the identification and predicting prognosis in colorectal cancers with mucinous differentiation

Accumulating evidence supports the fact that the mere presence of mucinous differentiation in colorectal cancer (CRC), rather than its proportion, is a more accurate representative of a particular CRC subtype with distinct clinical and molecular features. In addition, the prognostic significance of the mucinous carcinoma (MC) subtype remains poorly understood and biomarkers have been barely explored in this disease. Herein, we have performed a systematic and comprehensive analysis in MCs and non-MCs and identified a panel of microRNAs (miRNAs) that are differentially expressed between these two subtypes of CRC. Next, we interrogated their clinical significance and demonstrated their robust diagnostic and prognostic clinical ability in CRCs with mucinous differentiation. Finally, we established an integrative risk-assessment model by combining the miRNA-based risk scores together with TNM staging, which was a superior predictor of prognosis in mucinous CRC patients. Collectively, we report a novel miRNA biomarker panel for the identification and predicting survival in CRC patients with mucinous differentiation.

GLIDE: combining local methods and diffusion state embeddings to predict missing interactions in biological networks

Motivation

One of the core problems in the analysis of biological networks is the link prediction problem. In particular, existing interactions networks are noisy and incomplete snapshots of the true network, with many true links missing because those interactions have not yet been experimentally observed. Methods to predict missing links have been more extensively studied for social than for biological networks; it was recently argued that there is some special structure in protein–protein interaction (PPI) network data that might mean that alternate methods may outperform the best methods for social networks. Based on a generalization of the diffusion state distance, we design a new embedding-based link prediction method called global and local integrated diffusion embedding (GLIDE). GLIDE is designed to effectively capture global network structure, combined with alternative network type-specific customized measures that capture local network structure. We test GLIDE on a collection of three recently curated human biological networks derived from the 2016 DREAM disease module identification challenge as well as a classical version of the yeast PPI network in rigorous cross validation experiments.

Results

We indeed find that different local network structure is dominant in different types of biological networks. We find that the simple local network measures are dominant in the highly connected network core between hub genes, but that GLIDE’s global embedding measure adds value in the rest of the network. For example, we make GLIDE-based link predictions from genes known to be involved in Crohn’s disease, to genes that are not known to have an association, and make some new predictions, finding support in other network data and the literature.

Availability and implementation

GLIDE can be downloaded at https://bitbucket.org/kap_devkota/glide.

Supplementary information

Supplementary data are available at Bioinformatics online.

MicroRNA 452 regulates ASB8, NOL8, and CDR2 expression in colorectal cancer cells

BACKGROUND

MicroRNAs play important roles in the pathogenesis of human diseases by regulating target gene expression in specific cells or tissues. Previously, we identified microRNA 452 (MIR452), which was specifically up-regulated in early stage human colorectal cancer (CRC) tissue.

OBJECTIVE

The current study aims to identify and verify the target genes of MIR452 associated with CRC.

METHODS

A luciferase reporter system was used to confirm the effect of MIR452 on ASB8, NOL8, and CDR2 expression. The expression levels of MIR452 and the target genes were evaluated by quantitative RT-PCR (qRT-PCR) and western blotting.

RESULTS

We verified the association between MIR452 and three genes, ASB8, NOL8, and CDR2, and showed that their transcripts were down-regulated by MIR452. Up-regulated MIR452 also down-regulated ASB8, NOL8, and CDR2 mRNA and protein levels in CRC cells. CDR2 protein expression was decreased in CRC tissues compared to adjacent non-tumor tissues.

CONCLUSIONS

These results suggest that ASB8, NOL8, and CDR2 were target genes of MIR452 in CRC cells and that up-regulated MIR452 in CRC tissue regulated ASB8, NOL8, and CDR2 expression during colorectal carcinogenesis.

Reduced microRNA 375 in colorectal cancer upregulates metadherin-mediated signaling

BACKGROUND

The human microRNA 375 (MIR375) is significantly downregulated in human colorectal cancer (CRC) and we have previously shown that MIR375 is a CRC-associated miRNA. The metadherin (MTDH) is a candidate target gene of MIR375.

AIM

To investigate the interaction and function between MIR375 and MTDH in human CRC.

METHODS

A luciferase reporter system was used to confirm the effect of MIR375 on MTDH expression. The expression levels of MIR375 and the target genes were evaluated by quantitative RT-PCR (qRT-PCR), western blotting, or immunohistochemistry.

RESULTS

MTDH expression was found to be upregulated in human CRC tissues compared to that in healthy controls. We show that MIR375 regulates the expression of many genes involved in the MTDH-mediated signal transduction pathways [BRAF-MAPK and phosphatidylinositol-4,5-biphosphate-3-kinase catalytic subunit alpha (PIK3CA)-AKT] in CRC cells. Upregulated MTDH expression levels were found to inhibit NF-κB inhibitor alpha, which further upregulated NFKB1 and RELA expression in CRC cells.

CONCLUSION

Our findings suggest that suppressing MIR375 expression in CRC regulates cell proliferation and angiogenesis by increasing MTDH expression. Thus, MIR375 may be of therapeutic value in treating human CRC.

MARCKS and Lung Disease

MARCKS (myristoylated alanine-rich C kinase substrate) is a prominent PKC substrate expressed in all eukaryotic cells. It is known to bind to and cross-link actin filaments, to serve as a bridge between Ca²⁺/calmodulin and PKC signaling, and to sequester the signaling molecule phosphatidylinositol 4,5-bisphosphate in the plasma membrane. Since the mid-1980s, this evolutionarily conserved and ubiquitously expressed protein has been associated with regulating cellular events that require dynamic actin reorganization, including cellular adhesion, migration, and exocytosis. More recently, translational studies have implicated MARCKS in the pathophysiology of a number of airway diseases, including chronic obstructive pulmonary disease, asthma, lung cancer, and acute lung injury/acute respiratory distress syndrome. This article summarizes the structure and cellular function of MARCKS (also including MARCKS family proteins and MARCKSL1 [MARCKS-like protein 1]). Evidence for MARCKS's role in several lung diseases is discussed, as are the technological innovations that took MARCKS-targeting strategies from theoretical to therapeutic. Descriptions and updates derived from ongoing clinical trials that are investigating inhalation of a MARCKS-targeting peptide as therapy for patients with chronic bronchitis, lung cancer, and ARDS are provided.

MicroRNA 452 Regulates Cell Proliferation, Cell Migration, and Angiogenesis in Colorectal Cancer by Suppressing VEGFA Expression

The human microRNA 452 (MIR452) was identified as a colorectal cancer (CRC)-associated micro RNA (miRNA) by miRNA expression profiling of human CRC tissues versus normal colorectal tissues. It was significantly up-regulated in human CRC tissues. However, the functional mechanisms of MIR452 and its target genes in CRC remain unclear. We identified 27 putative MIR452 target genes, and found that the vascular endothelial growth factor A (VEGFA) was a direct target gene of MIR452. Both cellular and extracellular VEGFA levels were significantly downregulated in CRC cells upon their transfection with MIR452 or siVEGFA. VEGFA expression was frequently downregulated in human CRC tissues in comparison with that in their healthy counterparts. We showed that MIR452 regulated the expression of genes in the VEGFA-mediated signal transduction pathways vascular endothelial growth factor receptor 1 (VEGFR2)-mitogen-activated protein kinase (MAPK) and VEGFR2-SRC proto-oncogene non-receptor tyrosine kinase (SRC) in CRC cells. Immunohistological analyses of xenografted MIR452-overexpressing CRC cells in mice showed that MIR452 regulated cell proliferation and angiogenesis. Furthermore, aortic ring angiogenesis assay in rats clearly showed that the number of microvessels formed was significantly reduced by MIR452 transfection. Our findings suggest that MIR452 regulates cell proliferation, cell migration, and angiogenesis by suppressing VEGFA expression in early CRC progression; therefore, MIR452 may have therapeutic value in relation to human CRC.

Systematic large-scale meta-analysis identifies miRNA-429/200a/b and miRNA-141/200c clusters as biomarkers for necrotizing enterocolitis in newborn

Necrotizing enterocolitis (NEC) is a critical neonatal disease with a high mortality. The possibility that miRNAs may play an important role in NEC has raised great attention. Hence, the present study identified biomarkers that affected NEC in newborn progression through miRNA and gene expression profile analysis. miRNA chip GSE68054 and gene chip GSE46619 of NEC in newborn were analyzed to screen out differentially expressed miRNA and differentially expressed genes (DEGs). Next, target genes of differentially expressed miRNA were predicted, and differentially expressed miRNA-DEG regulatory network was constructed to select key miRNAs. After gene ontology and kyoto encyclopedia of genes and genomes enrichment analysis on target genes of key miRNAs, the target genes enriched in pathways were extracted to establish differentially expressed miRNA-DEG-disease gene network for gene interaction analysis. Targetting relationship between miRNAs and target genes was verified. A total of 15 miRNAs were differentially expressed in NEC in newborn, amongst which miR-429/200a/b and miR-141/200c clusters were poorly expressed and might play a significant role in NEC in newborn. Besides, target genes of miR-429/200a/b and miR-141/200c clusters were enriched in 11 signaling pathways. Vascular endothelial growth factor (VEGFA), E-selectin (SELE), kinase insert domain receptor (KDR), fms-related tyrosine kinase 1 (FLT1), and hepatocyte growth factor (HGF) were highly expressed in NEC in newborn, which were negatively regulated by miR-429/200a/b and miR-141/200c clusters and shared close association with disease genes. miR-429/200a/b and miR-141/200c clusters are poorly expressed while their target genes (VEGFA, SELE, KDR, FLT1, and HGF) are highly expressed in NEC in newborn, which might be identified as important biomarkers for this disease.

Infectious Threats, the Intestinal Barrier, and Its Trojan Horse: Dysbiosis

The ecosystem of the gut microbiota consists of diverse intestinal species with multiple metabolic and immunologic activities and it is closely connected with the intestinal epithelia and mucosal immune response, with which it builds a complex barrier against intestinal pathogenic bacteria. The microbiota ensures the integrity of the gut barrier through multiple mechanisms, either by releasing antibacterial molecules (bacteriocins) and anti-inflammatory short-chain fatty acids or by activating essential cell receptors for the immune response. Experimental studies have confirmed the role of the intestinal microbiota in the epigenetic modulation of the gut barrier through posttranslational histone modifications and regulatory mechanisms induced by epithelial miRNA in the epithelial lumen. Any quantitative or functional changes of the intestinal microbiota, referred to as dysbiosis, alter the immune response, decrease epithelial permeability and destabilize intestinal homeostasis. Consequently, the overgrowth of pathobionts (Staphylococcus, Pseudomonas, and Escherichia coli) favors intestinal translocations with Gram negative bacteria or their endotoxins and could trigger sepsis, septic shock, secondary peritonitis, or various intestinal infections. Intestinal infections also induce epithelial lesions and perpetuate the risk of bacterial translocation and dysbiosis through epithelial ischemia and pro-inflammatory cytokines. Furthermore, the decline of protective anaerobic bacteria (Bifidobacterium and Lactobacillus) and inadequate release of immune modulators (such as butyrate) affects the release of antimicrobial peptides, de-represses microbial virulence factors and alters the innate immune response. As a result, intestinal germs modulate liver pathology and represent a common etiology of infections in HIV immunosuppressed patients. Antibiotic and antiretroviral treatments also promote intestinal dysbiosis, followed by the selection of resistant germs which could later become a source of infections. The current article addresses the strong correlations between the intestinal barrier and the microbiota and discusses the role of dysbiosis in destabilizing the intestinal barrier and promoting infectious diseases.

MicroRNA 429 regulates the expression of CHMP5 in the inflammatory colitis and colorectal cancer cells

OBJECTIVE AND DESIGN

MicroRNAs (miRNAs) play an important role in the pathogenesis of human diseases by regulating the expression of target genes in specific cells or tissues. In this study, we analyzed the association between the MIR429 and its target gene, charged multivesicular body protein 5 (CHMP5), in human colon cancer cells and in a DSS-induced colitis mouse model.

MATERIALS AND METHODS

A luciferase reporter system was used to confirm the effect of MIR429 on CHMP5 expression. Protein or mRNA expression of the target gene and associated molecules were measured by Western blot or quantitative RT-PCR (qRT-PCR), respectively. Flow cytometry was used to compare cell viability or cell cycle progression.

RESULTS

CHMP5 mRNA and protein expression was directly down-regulated by MIR429. We found that MIR429 inhibited colon cancer cell growth and cell cycle progression, and CHMP5 was overexpressed in the DSS-induced colitis mouse model and human ulcerative colitis (UC) tissues.

CONCLUSIONS

Our findings show that CHMP5 is a direct target of MIR429 in human colon cancer cell lines and suggest that CHMP5 up-regulation as a result of reduced MIR429 expression in DSS-induced mice colitis tissues and human UC tissues may restrict apoptosis and promote cell proliferation.

Loss of MicroRNA-21 Influences the Gut Microbiota, Causing Reduced Susceptibility in a Murine Model of Colitis

BACKGROUND AND AIMS

microRNAs regulate gene expression and influence the pathogenesis of human diseases. The present study investigated the role of microRNA-21 [miR-21] in the pathogenesis of intestinal inflammation, because miR-21 is highly expressed in inflammatory bowel disease. Inflammatory bowel disease is associated with intestinal barrier dysfunction and an altered gut microbiota. Recent studies have demonstrated that host microRNAs can shape the microbiota. Thus, we determined the influence of miR-21 on the gut microbiota and observed the subsequent impact in a dextran sodium sulphate [DSS]-induced colitis model.

METHODS

The influence of miR-21 on the gut microbiota and inflammation was assessed in wild-type [WT] and miR-21-/- mice, in co-housed mice, following antibiotic depletion of the microbiota, or by colonization of germ-free [GF] mice with fecal homogenate, prior to DSS administration. We carried out 16S rRNA sequencing on WT and miR-21-/- mice to dissect potential differences in the gut microbiota.

RESULTS

miR-21-/- mice have reduced susceptibility to DSS-induced colitis compared with WT mice. Co-housing conferred some protection to WT mice, while GF mice colonized with fecal homogenate from miR-21-/- were protected from DSS colitis compared with those colonized with WT homogenate. Further supporting a role for the microbiota in the observed phenotype, the protection afforded by miR-21 depletion was lost when mice were pre-treated with antibiotics. The 16S rRNA sequencing revealed significant differences in the composition of WT and miR-21-/- intestinal microbiota.

CONCLUSIONS

These findings suggest that miR-21 influences the pathogenesis of intestinal inflammation by causing propagation of a disrupted gut microbiota.

MicroRNAs in intestinal barrier function, inflammatory bowel disease and related cancers-their effects and therapeutic potentials

The initiation and development or inflammatory bowel disease (IBD) and associated colorectal cancers, have been linked to inflammation. MicroRNAs are non-coding regulators of gene expression that have gained great attention due to their capability to regulate the expression of a number of target transcripts. It is now generally admitted that microRNAs are instrumental in gut pathologies, in particular through their targeting of transcripts encoding proteins of the intestinal barrier (IB) and their regulators. Intense research is conducted to identify microRNAs susceptible to be used as biomarkers and to design new therapeutic approaches based upon using synthetic microRNA mimics and inhibitors as well as finding new drugs capable to restore or modify microRNA expression in the context of gut pathologies.

MicroRNA 375 regulates proliferation and migration of colon cancer cells by suppressing the CTGF-EGFR signaling pathway

MicroRNA 375 (MIR375) is significantly down regulated in human colorectal cancer (CRC) tissues; we have previously identified MIR375 as a colon cancer associated microRNA (miRNA). We identified putative MIR375 target genes by comparing the mRNA microarray analysis data of MIR375-overexpressing cells with the candidate MIR375 target genes predicted by public bioinformatic tools. We investigated that the connective tissue growth factor (CTGF) is a direct target gene of MIR375. Expression of CTGF, a ligand of epidermal growth factor receptor (EGFR), was markedly enhanced in human CRC tissues in comparison with the corresponding normal colon tissues. We demonstrated that the expression levels of molecules in EGFR signaling pathways were regulated by MIR375 in colorectal cells. Using immunohistochemistry and the xenograft of MIR375-overexpressing colorectal cells in mice, we showed that MIR375 regulates cell growth and proliferation, angiogenesis, cell migration, cell cycle arrest, apoptosis, and necrosis in colon cells. Furthermore, results of MIR375 overexpression and cetuximab treatment indicated that the apoptosis and necrosis in colon cells were synergistically enhanced. Our results suggest that the down-regulation of MIR375 modulates EGFR signaling pathways in human colorectal cells and tissues by increasing CTGF expression; therefore, MIR375 may have a therapeutic value in relation to human CRC.