MicroRNA-23a mediates post-transcriptional regulation of CXCL12 in bone marrow stromal cells

BMSC-derived exosomal miR-148b-3p attenuates OGD/R-induced HMC3 cell activation by targeting DLL4 and Notch1

Bone mesenchymal stem cell (BMSC)-derived exosome (BMSC-Exo) could be a treatment method for ischemic injury. In ischemic cerebrovascular disease (IC), microglia is pivotal in neuronal damage and remodeling. This study explores the mechanisms of BMSC-Exo miR-148b-3p in regulating oxygen-glucose deprivation/reoxygenation (OGD/R)-induced human microglial clone 3 (HMC3) cell activation. Transmission electron microscopy (TEM) and qNano were used to assess BMSC-Exo features. The functions of BMSC-Exo miR-148 b-3p in OGD/R-induced HMC3 cell activation were explored via MTT assay, flow cytometry, scratch, transwell, and enzyme-linked immunosorbent assay (ELISA) assays. A dual-luciferase reporter assay was performed to determine the relationship between miR-148b-3p and Delta-like ligand 4(DDL4) or neurogenic locus notch homolog protein 1 (Notch1). OGD/R decreased miR-148b-3p expression in HMC3 cells. After BMSC-Exo treatment, miR-148b-3p expression was upregulated, cell viability and migration were inhibited, cell cycles remained in the G0/G1 phase, and proinflammatory cytokines were decreased in OGD/R-induced HMC3 cells. More importantly, BMSC-Exo miR-148b-3p could further strengthen BMSC-Exo effects. DDL4 and Notch1 are direct targets of miR-148b-3p, respectively. Moreover, the knockdown of DLL4 or Notch1 could inhibit OGD/R-induced HMC3 cell activation. BMSC-Exo miR-148b-3p inhibited OGD/R-induced HMC3 cell activation via inhibiting DLL4 and Notch1 expression, which provided a new strategy for treating cerebral ischemia.

The Role of Non-Coding RNAs in Myelodysplastic Neoplasms

Myelodysplastic syndromes or neoplasms (MDS) are a heterogeneous group of myeloid clonal disorders characterized by peripheral blood cytopenias, blood and marrow cell dysplasia, and increased risk of evolution to acute myeloid leukemia (AML). Non-coding RNAs, especially microRNAs and long non-coding RNAs, serve as regulators of normal and malignant hematopoiesis and have been implicated in carcinogenesis. This review presents a comprehensive summary of the biology and role of non-coding RNAs, including the less studied circRNA, siRNA, piRNA, and snoRNA as potential prognostic and/or predictive biomarkers or therapeutic targets in MDS.

Dysregulated miRNAs network in the critical COVID-19: An important clue for uncontrolled immunothrombosis/thromboinflammation

Known as a pivotal immunohemostatic response, immunothrombosis is activated to restrict the diffusion of pathogens. This beneficial intravascular defensive mechanism represents the close interaction between the immune and coagulation systems. However, its uncontrolled form can be life-threatening to patients with the critical coronavirus disease 2019 (COVID-19). Hyperinflammation and ensuing cytokine storm underlie the activation of the coagulation system, something which results in the provocation of more immune-inflammatory responses by the thrombotic mediators. This vicious cycle causes grave clinical complications and higher risks of mortality. Classified as an evolutionarily conserved family of the small non-coding RNAs, microRNAs (miRNAs) serve as the fine-tuners of genes expression and play a key role in balancing the pro/anticoagulant and pro-/anti-inflammatory factors maintaining homeostasis. Therefore, any deviation from their optimal expression levels or efficient functions can lead to severe complications. Despite their extensive effects on the molecules and processes involved in uncontrolled immunothrombosis, some genetic agents and uncontrolled immunothrombosis-induced interfering factors (e.g., miRNA-single nucleotide polymorphysms (miR-SNPs), the complement system components, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, and reactive oxygen species (ROS)) have apparently disrupted their expressions/functions. This review study aims to give an overview of the role of miRNAs in the context of uncontrolled immunothrombosis/thromboinflammation accompanied by some presumptive interfering factors affecting their expressions/functions in the critical COVID-19. Detecting, monitoring, and resolving these interfering agents mafy facilitate the design and development of the novel miRNAs-based therapeutic approaches to the reduction of complications incidence and mortality in patients with the critical COVID-19.

Micro-RNAs: A safety net to protect hematopoietic stem cell self-renewal

The hematopoietic system is sustained over time by a small pool of hematopoietic stem cells (HSCs). They reside at the apex of a complex hierarchy composed of cells with progressively more restricted lineage potential, regenerative capacity, and with different proliferation characteristics. Like other somatic stem cells, HSCs are endowed with long-term self-renewal and multipotent differentiation ability, to sustain the high turnover of mature cells such as erythrocytes or granulocytes, and to rapidly respond to acute peripheral stresses including bleeding, infections, or inflammation. Maintenance of both attributes over time, and of the proper balance between these opposite features, is crucial to ensure the homeostasis of the hematopoietic system. Micro-RNAs (miRNAs) are short non-coding RNAs that regulate gene expression posttranscriptionally upon binding to specific mRNA targets. In the past 10 years they have emerged as important players for preserving the HSC pool by acting on several biological mechanisms, such as maintenance of the quiescent state while preserving proliferation ability, prevention of apoptosis, premature differentiation, lineage skewing, excessive expansion, or retention within the BM niche. miRNA-mediated posttranscriptional fine-tuning of all these processes constitutes a safety mechanism to protect HSCs, by complementing the action of transcription factors and of other regulators and avoiding unwanted expansion or aplasia. The current knowledge of miRNAs function in different aspects of HSC biology, including consequences of aberrant miRNA expression, will be reviewed; yet unsolved issues will be discussed. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.

Oncogenic KrasG12D Activation in the Nonhematopoietic Bone Marrow Microenvironment Causes Myelodysplastic Syndrome in Mice

The bone marrow microenvironment (BMME) is key player in regulation and maintenance of hematopoiesis. Oncogenic RAS mutations, causing constitutive activation of multiple tumor-promoting pathways, are frequently found in human cancer. So far in hematologic malignancies, RAS mutations have only been reported to occur in hematopoietic cells. In this study, we investigated the effect of oncogenic Kras expression in the BMME in a chimeric mouse model. We observed that an activating mutation of Kras in the nonhematopoietic system leads to a phenotype resembling myelodysplastic syndrome (MDS) characterized by peripheral cytopenia, marked dysplasia within the myeloid lineage as well as impaired proliferation and differentiation capacity of hematopoietic stem and progenitor cells. The phenotypic changes could be reverted when the BM was re-isolated and transferred into healthy recipients, indicating that the Kras^G12D -activation in the nonhematopoietic BMME was essential for the MDS phenotype. Gene expression analysis of sorted nonhematopoietic BM niche cells from Kras^G12D mice revealed upregulation of multiple inflammation-related genes including IL1-superfamily members (Il1α, Il1β, Il1f9) and the NLPR3 inflammasome. Thus, pro-inflammatory IL1-signaling in the BMME may contribute to MDS development. Our findings show that a single genetic change in the nonhematopoietic BMME can cause an MDS phenotype. Oncogenic Kras activation leads to pro-inflammatory signaling in the BMME which impairs HSPCs function. IMPLICATIONS: These findings may help to identify new therapeutic targets for MDS.

A Zika virus primary isolate induces neuroinflammation, compromises the blood-brain barrier and upregulates CXCL12 in adult macaques

Zika virus (ZIKV) is a flavivirus that can cause neuropathogenesis in adults and fetal neurologic malformation following the infection of pregnant women. We used a nonhuman primate model, the Indian-origin Rhesus macaque (IRM), to gain insight into virus-associated hallmarks of ZIKV-induced adult neuropathology. We find that the virus causes prevalent acute and chronic neuroinflammation and chronic disruption of the blood-brain barrier (BBB) in adult animals. ZIKV infection resulted in specific short- and long-term augmented expression of the chemokine CXCL12 in the central nervous system (CNS)of adult IRMs. Moreover, CXCL12 expression persists long after the initial viral infection is apparently cleared. CXCL12 plays a key role both in regulating lymphocyte trafficking through the BBB to the CNS and in mediating repair of damaged neural tissue including remyelination. Understanding how CXCL12 expression is controlled will likely be of central importance in the definition of ZIKV-associated neuropathology in adults.

Identification of Unique mRNA and miRNA Expression Patterns in Bone Marrow Hematopoietic Stem and Progenitor Cells After Trauma in Older Adults

Older adults have significantly worse morbidity and mortality after severe trauma than younger cohorts. The competency of the innate immune response decreases with advancing age, especially after an inflammatory insult. Subsequent poor outcomes after trauma are caused in part by dysfunctional leukocytes derived from the host's hematopoietic stem and progenitor cells (HSPCs). Our objective was to analyze the bone marrow (BM) HSPC transcriptomic [mRNA and microRNA (miR)] responses to trauma in older and younger adults. BM was collected intraoperatively <9 days after initial injury from trauma patients with non-mild injury [ISS ≥ 9] or with shock (lactate ≥ 2, base deficit ≥ 5, MAP ≤ 65) who underwent operative fixation of a pelvic or long bone fracture. Samples were also analyzed based on age (<55 years and ≥55 years), ISS score and transfusion in the first 24 h, and compared to age/sex-matched controls from non-cancer elective hip replacement or purchased healthy younger adult human BM aspirates. mRNA and miR expression patterns were calculated from lineage-negative enriched HSPCs. 924 genes were differentially expressed in older trauma subjects vs. age/sex-matched controls, while 654 genes were differentially expressed in younger subjects vs. age/sex-matched control. Only 68 transcriptomic changes were shared between the two groups. Subsequent analysis revealed upregulation of transcriptomic pathways related to quantity, function, differentiation, and proliferation of HSPCs in only the younger cohort. miR expression differences were also identified, many of which were associated with cell cycle regulation. In summary, differences in the BM HSPC mRNA and miR expression were identified between older and younger adult trauma subjects. These differences in gene and miR expression were related to pathways involved in HSPC production and differentiation. These differences could potentially explain why older adult patients have a suboptimal hematopoietic response to trauma. Although immunomodulation of HSPCs may be a necessary consideration to promote host protective immunity after host injury, the age related differences further highlight that patients may require an age-defined medical approach with interventions that are specific to their transcriptomic and biologic response. Also, targeting the older adult miRs may be possible for interventions in this patient population.

miR-23c regulates wound healing by targeting stromal cell-derived factor-1α (SDF-1α/CXCL12) among patients with diabetic foot ulcer

Diabetic Foot Ulcer (DFU) is the most common in patients who have diabetic peripheral neuropathy and angiopathy as well as a foot deformity. The delayed process of wound healing in diabetic condition is mainly due to reduced expression of the growth factors, persistent inflammatory response and endothelial dysfunction. Emerging evidence indicate that miRNAs play a crucial role in regulating angiogenesis, collectively called as "angiomiRs". The present study aimed to screen the expressions of angiomiRs particularly miR23 family and its association with the various angiogenic factors including SDF-1α in the tissue biopsies isolated from DFU patients. Among the 40 enrolled subjects for this study, 10 were subjected in each group as healthy controls, type 2 diabetic subjects (T2DM), T2DM subjects with uninfected DFU, and T2DM subjects with infected DFU. The expression of both the miR23 family such as hsa-miR-23a, hsa-miR-23b, hsa-miR-23c and angiogenic factors such as SDF-1α, HIF-1α, VEGF, eNOS were investigated in peripheral blood mononuclear cells and tissue biopsy samples using qPCR. We found that the angiogenic factor SDF-1α was significantly decreased in both the circulation and tissue biopsies of patients with T2DM and infected DFU. The SDF-1α at the 3'-untranslated region pairs with target miRNAs namely hsa-miR-23a-3p, hsa-miR-23b-3p and hsa-miR-23c as established using miRNA target prediction algorithm. Further, the tissue-specific expressions of miR-23a and miR-23b were found to be low whereas miR-23c was increased in patients with infected DFU. Moreover, correlation analysis showed that SDF-1α was found to have a significant inverse association with miR-23c. In conclusion, miR-23c may function as a new regulator to inhibit angiogenesis by targeting SDF-1α.

microRNA-23a contributes to asthma by targeting BCL2 in airway epithelial cells and CXCL12 in fibroblasts

The deregulated cross-talk between airway epithelial cells with subepithelial fibroblasts during inflammation drives the pathogenesis of asthma. Bioinformatics analysis and luciferase activity assay suggested that B cell lymphoma-2 (BCL2) and CXC ligand 12 (CXCL12) are potential targets of miR-23a. The aim of this study was to elucidate the effect of microRNA-23a (miR-23a) on BCL2, and CXCL12 in asthma. In E3 rats, miR-23a was upregulated in lung tissues after antigen-induced pulmonary inflammation during acute and chronic inflammation. Immunohistochemistry showed downregulation of BCL2 in the epithelium and of CXCL12 in subepithelial fibroblasts and smooth muscle cells. Treatment of isolated cells with miR-23a mimic or inhibitor modified the expression of BCL2 and of CXCL12 in the expected cell type-specific manner. Moreover, in epithelial cells, interleukin-4 upregulated miR-23a expression and thereby decreased the expression of BCL2, while increasing the caspase-3 expression, which was followed by apoptosis. In fibroblasts, the expression of miR-23a was increased by thymic stromal lymphopoietin (TSLP). Consequently, the CXCL12 expression was abrogated. The phosphorylation of CREB was also downregulated by TSLP through the action of miR-23a. This study describes a novel mechanism, where miR-23a is an important cell type-specific regulator for asthma-associated airway wall remodeling parameter. Thus, miR-23a may present a potential new target for the therapy of asthma.

Role of p53 mediated miR-23a/CXCL12 pathway in osteogenic differentiation of bone mesenchymal stem cells on nanostructured titanium surfaces

Titanium surface modification is widely established and has been proven to improve the osseointegration, but the molecular mechanism remains to be fully elucidated. MicroRNAs serve vital roles in the process of regulating osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). In this study, we report that miR-23a was significantly down-regulated in the osteogenic differentiation process of BMSCs on nanostructured titanium surfaces. Elevated miR-23a inhibited osteogenic differentiation of BMSCs, and decreased miR-23a enhanced this process. In addition, we also observed that CXCL12 was a direct target of miR-23a. Knockdown of CXCL12 inhibited nanotube Ti induced-osteogenic differentiation of BMSCs, similar to the effect of upregulation of miR-23a. Finally, p53 was decreased and it regulated miR-23a/CXCL12 axis during nanotube Ti induced-osteogenic differentiation of BMSCs. Therefore, our findings suggest that by targeting CXCL12, miR-23a serves a vital role in osteogenic differentiation of BMSCs cultured on nanostructured titanium surfaces, which may provide novel clinical treatments for osseointegration.

Prophylactic Zinc and Therapeutic Selenium Administration Increases the Antioxidant Enzyme Activity in the Rat Temporoparietal Cortex and Improves Memory after a Transient Hypoxia-Ischemia

In the cerebral hypoxia-ischemia rat model, the prophylactic administration of zinc can cause either cytotoxicity or preconditioning effect, whereas the therapeutic administration of selenium decreases the ischemic damage. Herein, we aimed to explore whether supplementation of low doses of prophylactic zinc and therapeutic selenium could protect from a transient hypoxic-ischemic event. We administrated zinc (0.2 mg/kg of body weight; ip) daily for 14 days before a 10 min common carotid artery occlusion (CCAO). After CCAO, we administrated sodium selenite (6 μg/kg of body weight; ip) daily for 7 days. In the temporoparietal cerebral cortex, we determined nitrites by the Griess method and lipid peroxidation by the Gerard-Monnier assay. qPCR was used to measure mRNA of nitric oxide synthases, antioxidant enzymes, chemokines, and their receptors. We measured the enzymatic activity of SOD and GPx and protein levels of chemokines and their receptors by ELISA. We evaluated long-term memory using the Morris-Water maze test. Our results showed that prophylactic administration of zinc caused a preconditioning effect, decreasing nitrosative/oxidative stress and increasing GPx and SOD expression and activity, as well as eNOS expression. The therapeutic administration of selenium maintained this preconditioning effect up to the late phase of hypoxia-ischemia. Ccl2, Ccr2, Cxcl12, and Cxcr4 were upregulated, and long-term memory was improved. Pyknotic cells were decreased suggesting prevention of neuronal cell death. Our results show that the prophylactic zinc and therapeutic selenium administration induces effective neuroprotection in the early and late phases after CCAO.

Altered expression of microRNA-23a in psoriatic arthritis modulates synovial fibroblast pro-inflammatory mechanisms via phosphodiesterase 4B

OBJECTIVES

To investigate the functional role of miR-23a in synovial fibroblasts (SFC) activation in psoriatic arthritis (PsA).

METHODS

Differential expression of the miR-23a-27a-24-2 cluster was identified by real-time quantitative PCR in PsA synovial tissue and peripheral blood mononuclear cells (PBMC) compared to osteoarthritis (OA) and correlated with disease activity. For regulation experiments, PsA synovial fibroblasts (SFC) were cultured with Toll-like receptor (TLR) ligands and pro-inflammatory cytokines. PsA SFC were transfected with a miR-23a inhibitor to assess the functional effect on migration, invasion and expression of pro-inflammatory meditators. The direct interaction between miR-23a and predicted target mRNA, phosphodiesterase 4B (PDE4B), was examined by luciferase reporter gene assay, with the expression and regulation confirmed by RT-PCR and western blot. A PDE4 inhibitor was used to analyse the function of PDE4B signalling in both miR-23a and Poly(I:C)-induced PsA SFC activation.

RESULTS

Synovial tissue expression of miR-23a was lower in PsA compared to OA and correlated inversely with disease activity and synovitis. TLR activation via Poly(I:C) and LPS, but not Pam3CSK4, significantly decreased miR-23a expression, with no significant effect observed in reponse to stimulation with pro-inflammatory cytokines. Decreased miR-23a expression enhanced PsA SFC migration, invasion and secretion of IL-6, IL-8, MCP-1, RANTES and VEGF. We identified PDE4B as a direct target of miR-23a and demonstrated enhanced mRNA and protein expression of PDE4B in anti-miR-23a transfected PsA SFC. Poly(I:C) and/or miR-23a-induced migration and enhanced cytokine expression was suppressed by the blockade of PDE4 signalling.

CONCLUSIONS

In PsA, dysregulated miR-23a expression contributes to synovial inflammation through enhanced SFC activation, via PDE4B signalling, and identifies a novel anti-inflammatory mechanism of PDE4 blockade.

miRNA-23a/CXCR4 regulates neuropathic pain via directly targeting TXNIP/NLRP3 inflammasome axis

BACKGROUND

Chemokine CXC receptor 4 (CXCR4) in spinal glial cells has been implicated in neuropathic pain. However, the regulatory cascades of CXCR4 in neuropathic pain remain elusive. Here, we investigated the functional regulatory role of miRNAs in the pain process and its interplay with CXCR4 and its downstream signaling.

METHODS

miRNAs and CXCR4 and its downstream signaling molecules were measured in the spinal cords of mice with sciatic nerve injury via partial sciatic nerve ligation (pSNL). Immunoblotting, immunofluorescence, immunoprecipitation, and mammal two-hybrid and behavioral tests were used to explore the downstream CXCR4-dependent signaling pathway.

RESULTS

CXCR4 expression increased in spinal glial cells of mice with pSNL-induced neuropathic pain. Blocking CXCR4 alleviated the pain behavior; contrarily, overexpressing CXCR4 induced pain hypersensitivity. MicroRNA-23a-3p (miR-23a) directly bounds to 3' UTR of CXCR4 mRNA. pSNL-induced neuropathic pain significantly reduced mRNA expression of miR-23a. Overexpression of miR-23a by intrathecal injection of miR-23a mimics or lentivirus reduced spinal CXCR4 and prevented pSNL-induced neuropathic pain. In contrast, knockdown of miR-23a by intrathecal injection of miR-23a inhibitor or lentivirus induced pain-like behavior, which was reduced by CXCR4 inhibition. Additionally, miR-23a knockdown or CXCR4 overexpression in naïve mice could increase the thioredoxin-interacting protein (TXNIP), which was associated with induction of NOD-like receptor protein 3 (NLRP3) inflammasome. Indeed, CXCR4 and TXNIP were co-expressed. The mammal two-hybrid assay revealed the direct interaction between CXCR4 and TXNIP, which was increased in the spinal cord of pSNL mice. In particular, inhibition of TXNIP reversed pain behavior elicited by pSNL, miR-23a knockdown, or CXCR4 overexpression. Moreover, miR-23a overexpression or CXCR4 knockdown inhibited the increase of TXNIP and NLRP3 inflammasome in pSNL mice.

CONCLUSIONS

miR-23a, by directly targeting CXCR4, regulates neuropathic pain via TXNIP/NLRP3 inflammasome axis in spinal glial cells. Epigenetic interventions against miR-23a, CXCR4, or TXNIP may potentially serve as novel therapeutic avenues in treating peripheral nerve injury-induced nociceptive hypersensitivity.

The miR-25-93-106b cluster regulates tumor metastasis and immune evasion via modulation of CXCL12 and PD-L1

The stromal microenvironment controls response to injury and inflammation, and is also an important determinant of cancer cell behavior. However, our understanding of its modulation by miRNA (miR) and their respective targets is still sparse. Here, we identified the miR-25-93-106b cluster and two new target genes as critical drivers for metastasis and immune evasion of cancer cells. Using miR-25-93-106b knockout mice or antagomiRs, we demonstrated regulation of the production of the chemoattractant CXCL12 controlling bone marrow metastasis. Moreover, we identified the immune checkpoint PD-L1 (CD274) as a novel miR-93/106b target playing a central role in diminishing tumor immunity. Eventually, upregulation of miR-93 and miR-106b via miR-mimics or treatment with an epigenetic reader domain (BET) inhibitor resulted in diminished expression of CXCL12 and PD-L1. These data suggest a potential new therapeutic rationale for use of BET inhibitors for dual targeting of cancers with strong immunosuppressive and metastatic phenotypes.

The common variants implicated in microstructural abnormality of first episode and drug-naïve patients with schizophrenia

Both post-mortem and neuroimaging studies have identified abnormal white matter (WM) microstructure in patients with schizophrenia. However, its genetic underpinnings and relevant biological pathways remain unclear. In order to unravel the genes and the pathways associated with abnormal WM microstructure in schizophrenia, we recruited 100 first-episode, drug-naïve patients with schizophrenia and 140 matched healthy controls to conduct genome-wide association analysis of fractional anisotropy (FA) value measured using diffusing tensor imaging (DTI), followed by multivariate association study and pathway enrichment analysis. The results showed that one intergenic SNP (rs11901793), which is 20 kb upstream of CXCR7 gene on chromosome 2, was associated with the total mean FA values with genome-wide significance (p = 4.37 × 10⁻⁸), and multivariate association analysis identified a strong association between one region-specific SNP (rs10509852), 400 kb upstream of SORCS1 gene on chromosome 10, and the global trait of abnormal WM microstructure (p = 1.89 × 10⁻⁷). Furthermore, one pathway that is involved in cell cycle regulation, REACTOME_CHROMOSOME _MAINTENANCE, was significantly enriched by the genes that were identified in our study (p = 1.54 × 10⁻¹⁷). In summary, our study provides suggestive evidence that abnormal WM microstructure in schizophrenia is associated with genes that are likely involved in diverse biological signals and cell-cycle regulation although further replication in a larger independent sample is needed.

MicroRNA-130a-3p suppresses cell viability, proliferation and invasion in nasopharyngeal carcinoma by inhibiting CXCL12

Incidence of nasopharyngeal carcinoma (NPC) has remained high worldwide, posing a serious health problem. MicroRNAs (miRNAs) are a family of about 20-23 nucleotides small non-coding molecules, which play a significant role in NPC. In this study, we explored the molecular mechanisms of miR-130a-3p in inhibiting viability, proliferation, migration and invasion of NPC cells by suppressing CXCL12. The relative expression of miR-130a-3p and CXCL12 mRNA expression in tissues and cells was measured by qRT-PCR. NPC cell line CNE-2Z was transfected with miR-130a-3p mimics, CXCL12 siRNA, cDNA-CXCL12 and negative control. Western Blot was performed to detect CXCL12 expression. The MTT assay was performed to study cell viability. The colony formation assay was done to test cell growth. Flow cytometry was conducted to analyze cell cycle and apoptosis. The Transwell assay was used to investigate cell migration and invasion. The results found that the up-regulation of miR-130a-3p or down-regulation of CXCL12 could inhibit viability, proliferation, migration and invasion of CNE-2Z cells. Luciferase-reporting system assay was performed to investigate miR-130a-3p could bind to the 3'UTR region of CXCL12 and the overexpression of miR-130a-3p could suppress CXCL12 expression. Collectively, our finding suggested demonstrated that miR-130a-3p could prohibit the progression of NPC by suppressing CXCL12, which might serve as potential therapeutic targets for NPC.

Downregulation of CXCL12 in mesenchymal stromal cells by TGFβ promotes breast cancer metastasis

Mesenchymal stromal cells (MSCs) are one of major components of the tumour microenvironment. Recent studies have shown that MSC tumour residence and their close interactions with inflammatory factors are important factors that affect tumour progression. Among tumour-associated inflammatory factors, transforming growth factor β (TGFβ) is regarded as a key determinant of malignancy. By employing a lung metastasis model of a murine breast cancer, we show here that the prometastatic effect of MSCs was dependent on their response to TGFβ. Interestingly, we found that MSC-produced CXCL12, an important chemokine in tumour metastasis, was markedly inhibited by TGFβ. Furthermore, silencing of CXCL12 in TGFβ-unresponsive MSCs restored their ability to promote tumour metastasis. We found that 4T1 breast cancer cells expressed high levels of CXCR7, but not of CXCR4, both of which are CXCL12 receptors. In presence of CXCL12, CXCR7 expression on tumour cells was decreased. Indeed, when CXCR7 was silenced in breast cancer cells, their metastatic ability was inhibited. Therefore, our data demonstrated that sustained expression of CXCL12 by MSCs in the primary tumour site inhibits metastasis through reduction of CXCR7, while, in the presence of TGFβ, this CXCL12 effect of MSCs on tumour cells is relieved. Importantly, elevated CXCR7 and depressed CXCL12 expression levels were prominent features of clinical breast cancer lesions and were related significantly with poor survival. Our findings reveal a novel mechanism of MSC effects on malignant cells through which crosstalk between MSCs and TGFβ regulates tumour metastasis.

Connexin's Connection in Breast Cancer Growth and Progression

Gap junctions are cell-to-cell junctions that are located in the basolateral surface of two adjoining cells. A gap junction channel is composed of a family of proteins called connexins. Gap junction channels maintain intercellular communication between two cells through the exchange of ions, small metabolites, and electrical signals. Gap junction channels or connexins are widespread in terms of their expression and function in maintaining the development, differentiation, and homeostasis of vertebrate tissues. Gap junction connexins play a major role in maintaining intercellular communication among different cell types of normal mammary gland for proper development and homeostasis. Connexins have also been implicated in the pathogenesis of breast cancer. Differential expression pattern of connexins and their gap junction dependent or independent functions provide pivotal cross talk of breast tumor cells with the surrounding stromal cell in the microenvironment. Substantial research from the last 20 years has accumulated ample evidences that allow us a better understanding of the roles that connexins play in the tumorigenesis of primary breast tumor and its metastatic progression. This review will summarize the knowledge about the connexins and gap junction activities in breast cancer highlighting the differential expression and functional dynamics of connexins in the pathogenesis of the disease.

A signature of 12 microRNAs is robustly associated with growth rate in a variety of CHO cell lines

As Chinese Hamster Ovary (CHO) cells are the cell line of choice for the production of human-like recombinant proteins, there is interest in genetic optimization of host cell lines to overcome certain limitations in their growth rate and protein secretion. At the same time, a detailed understanding of these processes could be used to advantage by identification of marker transcripts that characterize states of performance. In this context, microRNAs (miRNAs) that exhibit a robust correlation to the growth rate of CHO cells were determined by analyzing miRNA expression profiles in a comprehensive collection of 46 samples including CHO-K1, CHO-S and CHO-DUKXB11, which were adapted to various culture conditions, and analyzed in different growth stages using microarrays. By applying Spearman or Pearson correlation coefficient criteria of>|0.6|, miRNAs with high correlation to the overall growth, or growth rates observed in exponential, serum-free, and serum-free exponential phase were identified. An overlap of twelve miRNAs common for all sample sets was revealed, with nine positively and three negatively correlating miRNAs. The here identified panel of miRNAs can help to understand growth regulation in CHO cells and contains putative engineering targets as well as biomarkers for cell lines with advantageous growth characteristics.

The role of microRNA in myelodysplastic syndromes: beyond DNA methylation and histone modification

Myelodysplastic syndromes (MDS) are heterogeneous group of hematologic disorders of mostly elderly and based on distinct clinical phenotypes. Current paradigm of their pathogenesis relies on somatic gene mutations combined with the predisposing defective osteohematopoietic niche, but due to the breakout in epigenetic research scientific focus has steered toward two most common epigenetic modifications: methylation mechanisms and histone modification. At the same time, relatively few studies have been undertaken regarding the third epigenetic pathway - microRNAs - in MDS. The main aim of this review is to provide the basics of microRNA biology and function in oncogenesis, showing the complexity of mechanisms behind this single-stranded 22 nucleotides long RNA molecule, with further focus on its implication in MDS pathology and clinical context. By extensive literature search, we have shown enough evidence for their deregulation in MDS. However, few studies have addressed the issue on pathogenic events in MDS and its association with specific microRNAs. Preliminary research in clinical setting has shown the possible utility of microRNAs in terms of prognosis and therapy, although we are only beginning to understand various implications of microRNAs in MDS and further extensive research is warranted to answer multiple questions arising from interconnection of this epigenetic mechanism in MDS.

The functional role of microRNA in acute lymphoblastic leukemia: relevance for diagnosis, differential diagnosis, prognosis, and therapy

MicroRNAs (miRNAs), a new class of noncoding RNAs, which can hybridize to target messenger RNAs and regulate their expression posttranscriptionally, express differentially in distinct stages of lymphopoiesis and influence the direction of lymphoid precursor maturation. Hence, there is aberrant expression of miRNAs involved in malignant lymphopoiesis, and these aberrations can be used as signatures of acute lymphoblastic leukemia (ALL) with different subtypes. In addition, changes in the expression of several miRNAs may have functional relevance with leukemogenesis or drug resistance. As a result, the reversal of the expression of these miRNAs may alleviate the disease to some extent and improve clinical outcomes. However, among the studies of miRNAs, there are still some problems that need to be solved to understand the function of miRNAs in ALL more thoroughly.