2019

Permanent URI for this collectionhttps://hdl.handle.net/1807/92944

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Eukaryotic initiation factor 5B (eIF5B) regulates temozolomide-mediated apoptosis in brain tumour stem cells (BTSCs)
(Canadian Science Publishing, 2019-10-24) Ross, Joseph A.; Ahn, Bo Young; King, Jennifer; Bressler, Kamiko R.; Senger, Donna L.; Thakor, Nehal
Glioblastoma multiforme (GBM) is among the deadliest cancers, owing in part to complex inter- and intra-tumor heterogeneity and the presence of a population of stem-like cells called brain tumour stem cells (BTSCs/BTICs). These cancer stem cells survive treatment and confer resistance to the current therapies — namely, radiation and the chemotherapeutic, temozolomide (TMZ). TMZ induces cell death by alkylating DNA, and BTSCs resist this mechanism via a robust DNA damage response. Hence, recent studies aimed to sensitize BTSCs to TMZ using combination therapy, such as inhibition of DNA repair machinery. We have previously demonstrated in established GBM cell lines that eukaryotic initiation factor 5B (eIF5B) promotes the translation of pro-survival and anti-apoptotic proteins. Consequently, silencing eIF5B sensitizes these cells to TRAIL-induced apoptosis. However, established cell lines do not always recapitulate the features of human glioma. Therefore, we investigated this mechanism in patient-derived BTSCs. We show that silencing eIF5B leads to increased TMZ sensitivity in two BTSC lines: BT25 and BT48. Depletion of eIF5B decreases the levels of anti-apoptotic proteins in BT48 and sensitizes these cells to TMZ-induced activation of caspase-3, cleavage of PARP, and apoptosis. We suggest that eIF5B represents a rational target to sensitize GBM tumors to the current standard-of-care.
MiR-448 targets BLC2 and inhibits the growth of pituitary adenoma cells
(Canadian Science Publishing, 2019-12-16) He, Chao; Yang, Jun; Ding, Jiawang; Li, Song; Wu, Hui; Zhou, Fei; Teng, Lin; Yang, Jian
There is an increasing body of evidence indicating the important roles of miRNAs in the progression of pituitary adenoma. Recent studies have shown decreased expression and tumor suppressive function of miR-448 in cancers; however, the clinical significance of miR-448 in pituitary adenoma has remained largely unknown. In our study, we found that miR-448 was down-regulated in pituitary adenoma tissues and cell lines. Overexpression of miR-448 significantly inhibited the proliferation and migration of pituitary adenoma cells. Increased cell apoptosis was also observed with overexpression of miR-448. To further understand the mechanisms behind the regulation of pituitary adenoma by miR-448 in, the targets of miR-448 were predicted using the bioinformatics tools. B cell lymphoma 2 (BCL2) was identified as a target of miR-448. MiR-448 bound the 3′-untranslated region (UTR) of BCL2 and inhibited the expression of BCL2 in pituitary adenoma cells. There was a consistent and significantly negative correlation between the level of miR-448 and BCL2 in pituitary adenoma tissues. When BCL2 was highly expressed, the inhibitory impact of miR-448 on the proliferation and apoptosis of pituitary adenoma cells was significantly inhibited. Collectively, our findings emphasize the significance of the miR-448–BCL2 axis in the development of pituitary adenoma, highlighting the potential therapeutic significance of miR-448 in pituitary adenoma.
MiR-539 inhibited the malignant behaviors of breast cancer cells by targeting SP1
(Canadian Science Publishing, 2019-07-18) Cai, Fenglin; Chen, Luhong; Sun, Yuting; He, Chunlan; Fu, Deyuan; Tang, Jinhai
The aberrant expression of microRNAs (miRNAs) is involved in the initiation and progression of human cancers. In our study, we found that miR-539 was down-regulated in breast cancer tissues and cell lines. Decreased expression of miR-539 was significantly associated with lymph node metastasis in patients with breast cancer. Overexpression of miR-539 inhibited the proliferation and promoted apoptosis of breast cancer cells. Moreover, highly expressed miR-539 significantly suppressed the epithelial–mesenchymal transition (EMT) and sensitized cells to cisplatin treatment. Mechanistically, miR-539 was found to target the specificity protein 1 (SP1) and down-regulated the expression of SP1 in breast cancer cells. Knockdown of miR-539 consistently increased the expression of SP1. The expression of miR-539 in breast cancer tissues was negatively correlated with the expression of SP1. Restoration of SP1 significantly attenuated the inhibitory effect of miR-539 on the proliferation of breast cancer cells. Taken together, our results indicate that miR-539 has a tumor suppressive role in breast cancer via targeting SP1, suggesting miR-539 as a promising target for the diagnosis of breast cancer.
Inhibition of brain-type glycogen phosphorylase ameliorates high glucose-induced cardiomyocyte apoptosis via Akt-HIF-1α activation
(Canadian Science Publishing, 2019-12-16) Wu, Xuehan; Huang, Weilu; Quan, Minxue; Chen, Yongqi; Tu, Jiaxin; Zhou, Jialu; Xin, Hong-Bo; Qian, Yisong
Brain-type glycogen phosphorylase (pygb) is one of the rate-limiting enzymes in glycogenolysis that plays a crucial role in the pathogenesis of type 2 diabetes mellitus. Here we investigated the role of pygb in high-glucose (HG)-induced cardiomyocyte apoptosis and explored the underlying mechanisms, by using the specific pygb inhibitors or pygb siRNA. Our results show that inhibition of pygb significantly attenuates cell apoptosis and oxidative stress induced by HG in H9c2 cardiomyocytes. Inhibition of pygb improved glucose metabolism in cardiacmyocytes, as evidenced by increased glycogen content, glucose consumption, and glucose transport. Mechanistically, pygb inhibition activates the Akt–GSK-3β signaling pathway and suppresses the activation of NF-κB in H9c2 cells exposed to HG. Additionally, pygb inhibition promotes the expression and the translocation of hypoxia-inducible factor-1α (HIF-1α) after HG stimulation. However, the changes in glucose metabolism and HIF-1α activation mediated by pygb inhibition are significantly reversed in the presence of the Akt inhibitor MK2206. In conclusion, this study found that inhibition of pygb prevents HG-induced cardiomyocyte apoptosis via activation of Akt–HIF-α.
PLOD2 promotes aerobic glycolysis and cell progression in colorectal cancer by upregulating HK2
(Canadian Science Publishing, 2019-10-24) Du, Wenwu; Liu, Ning; Zhang, Yafeng; Liu, Xi; Yang, Yuanhong; Chen, Wei; He, Yi
The purpose of the current study is to characterize the expression of procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), a membrane-bound homodimeric enzyme that specifically hydroxylates lysine in the telopeptide of procollagens, and assess the clinical significance of PLOD2 in colorectal cancer (CRC). Our results showed that PLOD2 was highly expressed in CRC tumor tissues samples and cell lines both in mRNA and protein level. Next, we found that PLOD2 was positively correlated with Grade (p=0.001), T stage (p=0.001), N stage (p
Active vitamin D activates chondrocyte autophagy to reduce osteoarthritis via mediating the AMPK–mTOR signaling pathway
(Canadian Science Publishing, 2019-11-24) Kong, Chunyu; Wang, Changlei; Shi, Yuquan; Yan, Lei; Xu, Junhua; Qi, Wufang
Osteoarthritis (OA) is a common joint degenerative disease. Vitamin D (VD) is essential for bone health. We hypothesized that active VD could be used as a therapeutic treatment for OA. Low serum levels of 25-hydroxyvitamin D [25(OH)D] have been found in patients with OA, and thus the serum level of VD could be diagnostic of OA. To test this, we established a mouse model of OA. The results from staining with hematoxylin–eosin and Safranin O – Fast Green indicated that active VD reduced the symptoms of OA in mice. The results from Western blotting indicated that treatment with VD increased the activity of the p-AMPK–AMPK signaling pathway and decreased the p-mTOR–mTOR pathway; it also increased the ratio of LC3II:LC3I antibodies and the protein expression levels of Beclin-1, but decreased the level of p62. Further, treatment with VD reduced the levels of tumor necrosis factor-α and interleukin-6 both in cartilage tissues and in chondrocytes. Administration of the AMPK inhibitor compound C and autophagy inhibitor 3-methyladenine (3-MA) reversed these changes following VD treatment. In addition, the results from transfection with mRFP-GFP-LC3 indicated that active VD led to autophagosome aggregation in OA chondrocytes. 3-MA inhibited cell autophagy and promoted inflammation in OA. This study provides evidence that active VD activate chondrocyte autophagy to reduce OA inflammation via activating the AMPK–mTOR signaling pathway. Treatment with active VD could be a novel therapeutic option for OA.
Homogeneity and heterogeneity of biological characteristics in mesenchymal stem cells from human umbilical cords and exfoliated deciduous teeth
(Canadian Science Publishing, 2019-11-27) Yang, Chao; Chen, Yu; Zhong, Liwu; You, Min; Yan, Zhiling; Luo, Maowen; Zhang, Bo; Yang, Benyanzi; Chen, Qiang
Mesenchymal stem cells (MSCs) have proven powerful potential for cell-based therapy both in regenerative medicine and disease treatment. Human umbilical cords and exfoliated deciduous teeth are the main sources of MSCs with no donor injury or ethical issues. The goal of this study was to investigate the differences in the biological characteristics of human umbilical cord mesenchymal stem cells (UCMSCs) and stem cells from human exfoliated deciduous teeth (SHEDs). UCMSCs and SHEDs were identified by flow cytometry. The proliferation, differentiation, migration, chemotaxis, paracrine, immunomodulatory, neurite growth-promoting capabilities, and acetaldehyde dehydrogenase (ALDH) activity were comparatively studied between these two MSCs in vitro. The results showed that both SHEDs and UCMSCs expressed cell surface markers characteristic of MSCs. Furthermore, SHEDs exhibited better capacity for proliferation, migration, promotion of neurite growth, and chondrogenic differentiation. Meanwhile, UCMSCs showed more outstanding adipogenic differentiation and chemotaxy. Additionally, there were no significant differences in osteogenic differentiation, immunomodulatory capacity, and the proportion of ALDHBright compartment. Our findings indicate that although both UCMSCs and SHEDs are mesenchymal stem cells and presented some similar biological characteristics, they also have differences in many aspects, which might be helpful for developing future clinical cellular therapies.
Circ_KATNAL1 regulates prostate cancer cell growth and invasiveness through the miR-145-3p/WISP1 pathway
(Canadian Science Publishing, 2019-11-27) Zheng, Yu; Chen, Chao-jiang; Lin, Zhuo-yuan; Li, Jian-xin; Liu, Jie; Lin, Fu-jun; Zhou, Xing
Prostate cancer (PCa) is the second leading cause of death in men, and current studies have shown that circular RNAs (circRNAs) play important roles in its occurrence and development. Detection of circRNAs in PCa cells showed that circ_KATNAL1 is down-regulated, mainly located in the cytoplasm, and contains multiple binding sites of miR-145-3p, which is an anticancer miRNA. RNA immunoprecipitation with anti-AGO2 antibody, RNA pull-down assays with biotin-labeled circ_KATNAL1 probe or an miR-145-3p mimic, and dual luciferase reporter gene assays confirmed that circ_KATNAL1 binds directly to miR-145-3p in cells, and that WISP1, which is highly expressed in many types of tumors, is an important target gene of miR-145-3p. Circ_KATNAL1 and miR-145-3p promote each other’s expression, and down-regulate the expression of the target gene WISP1. Both circ_KATNAL1 and miR-145-3p inhibit cell proliferation, invasiveness, and migration, down-regulate the expression of MMP-2 and MMP-9, promote cell apoptosis and the activation of caspase-3, caspase-8, caspase-9, and PARP, whereas WISP1 has the opposite effect, and the above-mentioned functions of circ_KATNAL1 were achieved through the miR-145-3p/WISP1 pathway. Therefore, circ_KATNAL1 plays an anticancer role in PCa cells through the miR-145-3p/WISP1 pathway, which could be an important target for the diagnosis and treatment of PCa.
Glycerol kinase enhances hepatic lipid metabolism by repressing nuclear receptor subfamily 4 group A1 in the nucleus
(Canadian Science Publishing, 2019-10-31) Miao, Lili; Su, Fei; Yang, Yongsheng; Liu, Yue; Wang, Lei; Zhan, Yiqun; Yin, Ronghua; Yu, Miao; Li, Changyan; Yang, Xiaoming; Ge, Changhui
Glycerol kinase (GYK) plays a critical role in hepatic metabolism by converting glycerol to glycerol 3-phosphate in an ATP-dependent reaction. GYK isoform b is the only glycerol kinase present in whole cells, and has a non-enzymatic moonlighting function in the nucleus. GYK isoform b acts as a co-regulator of nuclear receptor subfamily 4 group A1 (NR4A1) and participates in the regulation of hepatic glucose metabolism by protein–protein interaction with NR4A1. Herein, GYK expression was found to upregulate the expression of NR4A1-mediated lipid metabolism-related genes (SREBP1C, FASN, ACACA, and GPAM) in HEK293T and L02 cells, and in mouse in vivo studies. GYK expression increased blood levels of cholesterol, triglyceride, and high-density lipoprotein cholesterol, but not low-density lipoprotein cholesterol levels. It enhanced the transcriptional activity of Nr4a1 target genes by negatively cooperating with NR4A1 and its enzymatic activity or by other undefined moonlighting functions. This enhancement was observed in both normal and diabetic mice. We also found a feed-forward regulation loop between GYK and NR4A1, serving as part of a GYK-NR4A1 regulatory mechanism in hepatic metabolism. Thus, GYK regulates the effect of NR4A1 on hepatic lipid metabolism in normal and diabetic mice, partially through the cooperation of GYK and NR4A1.
Protective effect of nitronyl nitroxide against hypoxia induced damage in PC12 cells
(Canadian Science Publishing, 2019-11-04) Luo, Hongbo; Sun, Wei; Shao, Jin; Ma, Huiping; Jia, Zhengping; Jing, Linlin
Hypoxia induces cellular oxidative stress that is associated with neurodegenerative diseases. HPN (4′-hydroxyl-2-substituted phenyl nitronyl nitroxide), a stable nitronyl nitroxide, has excellent free radical scavenging properties. The purpose of this study was to investigate the protective effects of HPN on hypoxia-induced damage in PC12 cells. It was shown that HPN significantly attenuated hypoxia-induced loss of cell viability, release of lactate dehydrogenase (LDH), and morphological changes in PC12 cells. Moreover, hypoxic PC12 cells had increased levels of reactive oxygen species (ROS), malondialdehyde (MDA), and expression of HIF-1α and VEGF, but had reduced levels of superoxide dismutase (SOD) and catalase (CAT), and HPN reversed these changes. HPN also inhibited hypoxia-induced cell apoptosis via suppressing the expression of Bax, cytochrome c, and caspase-3, and inducing the expression of Bcl-2. These results indicate that the protective effects of HPN on hypoxia-induced damage in PC12 cells is associated with the suppression of hypoxia-induced oxidative stress and cell apoptosis. HPN could be a promising candidate for the development of a novel neuroprotective agent.
Connecting proteins: shareable tools for reproducible interaction mapping
(Canadian Science Publishing, 2019-09-30) Gingras, Anne-Claude
A summary of the Jeanne Manery Fisher Memorial Lecture presented at the CSMB meeting in Montreal, June 2019.
PML isoform expression and DNA break location relative to PML nuclear bodies impacts the efficiency of homologous recombination
(Canadian Science Publishing, 2019-10-24) Attwood, Kathleen M.; Salsman, Jayme; Chung, Dudley; Mathavarajah, Sabateeshan; Van Iderstine, Carter; Dellaire, Graham
Promyelocytic leukemia nuclear bodies (PML NBs) are nuclear subdomains that respond to genotoxic stress by increasing in number via changes in chromatin structure. However, the role of the PML protein and PML NBs in specific mechanisms of DNA repair has not been fully characterized. Here, we have directly examined the role of PML in homologous recombination (HR) using I-SceI extrachromosomal and chromosome-based homology-directed repair (HDR) assays, and in HDR by CRISPR/Cas9-mediated gene editing. We determined that PML loss can inhibit HR in an extrachromosomal HDR assay but had less of an effect on CRISPR/Cas9-mediated chromosomal HDR. Overexpression of PML also inhibited both CRISPR HDR and I-SceI-induced HDR using a chromosomal reporter, and in an isoform specific-manner. However, the impact of PML overexpression on the chromosomal HDR reporter was dependent on the intra-nuclear chromosomal positioning of the reporter. Specifically, HDR at the TAP1 gene locus, which is associated with PML NBs, was reduced compared to a locus not associated with a PML NB; yet, HDR could be reduced at the non-PML NB-associated locus by PML overexpression. Thus, both loss and overexpression of PML isoforms can inhibit HDR, and proximity of a chromosomal break to a PML NB can impact HDR efficiency.
miR-140-5p targeted FGF9 and inhibited the cell growth of laryngeal squamous cell carcinoma
(Canadian Science Publishing, 2019-02-05) Wang, Ying; Huang, Qingli; Li, Faping
Increasing evidence has suggested that microRNAs (miRNAs) play critical roles in the initiation and development of cancers. Here, we found that miR-140-5p was significantly downregulated in both laryngeal squamous cell carcinoma (LSCC) tissues and cell lines. Decreased expression of miR-140-5p was significantly associated with the metastasis of LSCC. Overexpression of miR-140-5p inhibited proliferation and induced apoptosis of LSCC cells. Mechanistically, the fibroblast growth factor 9 (FGF9) was identified as the target of miR-140-5p. miR-140-5p bound the 3′-untranslated region (3′-UTR) of FGF9 and suppressed the expression of FGF9 in LSCC cells. Additionally, the level of FGF9 was upregulated in LSCC tissues and negatively correlated with the expression of miR-140-5p. Restoration of FGF9 attenuated the suppressive role of miR-140-5p in regulating the growth of LSCC cells. Collectively, these results indicated that the tumor suppressive function of miR-140-5p in LSCC was partially exercised by modulating the expression of FGF9.
Subcellular fractionation of frozen skeletal muscle samples
(Canadian Science Publishing, 2019-09-27) Firmino Dias, Pedro Rafael; Gandra, Paulo Guimares; Brenzikofer, Ren; Macedo, Denise Vaz
Cell fractionation can be used to determine the localization and trafficking of proteins between cellular compartments such as cytosol, mitochondria and nuclei. Subcellular fractionation is usually performed immediately after tissue dissection since freezing may fragment cell membranes and induce organellar cross-contamination. Mitochondria are especially sensitive to freezing/thawing and mechanical homogenization. We proposed a protocol to improve soluble proteins retention in the mitochondrial fraction obtained from small amounts of frozen skeletal muscle. Fifty-milligram of red portion of gastrocnemius muscle from Wistar rats were immediately processed or frozen in liquid nitrogen and stored at −80C for further processing. We compared the enrichment of subcellular fractions from frozen/fresh samples obtained with the modified protocol with those obtained by standard fractionation. Western blot analyses of marker proteins for cytosolic (alpha-tubulin), mitochondrial (VDAC1), and nuclear (histone-H3) fractions indicated that all procedures resulted in enriched subcellular fractions with minimal organellar cross-contamination. Notably, the activity of the soluble protein citrate synthase was higher in mitochondrial fractions obtained with the modified protocol from frozen/fresh samples compared to the standard protocol. Therefore, our protocol improved the retention of soluble proteins in the mitochondrial fraction and may be suitable for subcellular fractionation of small amounts of frozen skeletal muscle samples.
MiR-126 targets IL-17A to enhance proliferation and inhibit apoptosis in high-glucose-induced human retinal endothelial cells
(Canadian Science Publishing, 2019-08-13) Chen, Xiujuan; Yu, Xuequn; Li, Xinxiang; Li, Li; Li, Fang; Guo, Ting; Guan, Cuihong; Miao, Liping; Cao, Guoping
Diabetic retinopathy (DR) is a common complication of diabetes mellitus (DM), which results in vision loss. The present study aimed to explore the role of miR-126 in high-glucose-induced human retinal endothelial cells (HRECs) and its underlying molecular mechanism. The results showed that expression of miR-126 and interleukin-17A (IL-17A) in high-glucose-induced HRECs was downregulated and upregulated, respectively. Functionally, overexpression of miR-126 promoted proliferation and suppressed apoptosis in high-glucose-induced HRECs, while IL-17A reversed the effects induced by miR-126. However, overexpression of IL-17A inhibited the proliferation and induced apoptosis, while knockdown of IL-17A accelerated the proliferation and repressed apoptosis. In addition, miR-126 repressed the expression of IL-17A, Bax, and caspase-3,while promotingthe expression of survivin and phosphorylation of PI3K and AKT;restoration of IL-17A rescued these effects. Furthermore, IL-17A was identified as a target of miR-126. Altogether, miR-126 enhances proliferation and inhibits apoptosis in high-glucose-induced HRECs by activating the PI3K/AKT pathway, increasing survivinand decreasing Bax and caspase-3 expression by targeting IL-17A, suggesting that miR-126 may be a novel target for preventing DR.
MicroRNA-1298-5p inhibits cell proliferation and invasion of bladder cancer via downregulating connexin 43
(Canadian Science Publishing, 2019-09-10) Li, Gang; Sun, Longfeng; Mu, Zhongyi; Liu, Shibo; Qu, Hongchen; Xie, Qingpeng; Hu, Bin
MicroRNA (miR)-1298 is widely down-regulated in a variety of malignant tumors, which facilitates cell proliferation, invasiveness, and migration. However, the specific biological function of miR-1298 in bladder cancer (BC) is still unknown. Connexin 43 (Cx43) is often up-regulated in tumors. Identifying miRNAs that target Cx43 in the setting of BC will help to develop Cx43-based therapies for BC. In this study, the results demonstrated that the expression levels of miR-1298 and Cx43 were significantly down-regulated and up-regulated, respectively, in BC tissues. Overexpression of miR-1298 inhibited cell proliferation, migration, and invasiveness in two BC cell lines as determined using MTT assays, cell cycle assays, colony formation assays, Transwell assays, gelatin zymography, and Western blot. In addition, we found that miR-1298 decreased Cx43 expression by directly targeting the 3′-UTR. Further, we observed that the promotion of BC cell proliferation, migration, and invasiveness from Cx43 on could be partially attenuated by overexpressing miR-1298. Moreover, the protein expression of p-ERK was ameliorated after transfection with overexpressed-miR-1298. Knockdown of Cx43 reversed the promotion of cell migration and invasiveness due to decreased expression of miR-1298. All of the data from our study indicate that miR-1298 could be a diagnostic marker of BC and a potential therapeutic agent via inhibiting Cx43.
Extracellular pyruvate kinase M2 facilitates cell migration by upregulating claudin-1 expression in colon cancer cells
(Canadian Science Publishing, 2019-09-04) Kim, Hyunju; Kim, Seong Ho; Hwang, Dohyeon; An, Jinsu; Chung, Hak Suk; Yang, Eun Gyeong; Kim, So Yeon
Extensive studies have been reported the non-canonical functions of pyruvate kinase M2 (PKM2) as kinase, transcriptional regulator and even cell-to-cell communicator, emphasizing its importance in various signaling pathways. However, the role of secreted PKM2 in cancer progression and its signaling pathway is yet to be elucidated. In this study, we found that extracellular PKM2 enhanced the migration of low-metastatic, benign colon cancer cells by upregulating claudin-1 expression and internalizing it to the cytoplasm and nucleus. Knock down of claudin-1 significantly reduced extracellular PKM2-induced cell migration. Inhibition of either protein kinase C (PKC) or epidermal growth factor receptor (EGFR) resulted in a reduction of extracellular PKM2 mediated claudin-1 expression, suggesting EGFR-PKC-claudin-1 as a signaling pathway in the extracellular PKM2-mediated tumorigenesis of colon cancer cells.
Genes responsive to rapamycin and serum deprivation are clustered on chromosomes and undergo reorganization within local chromatin environments.
(Canadian Science Publishing, 2019-07-10) Belak, Zachery R.; Pickering, Joshua A.; Gillespie, Zoe E; Audette, Gerald F.; Eramian, Mark; Mitchell, Jennifer A; Bridger, Joanna M.; Kusalik, Anthony; Eskiw, Christopher H.
We previously demonstrated that genome reorganization, through chromosome territory repositioning, occurred concurrently with significant changes in gene expression in normal primary human fibroblasts treated with the drug rapamycin, or stimulated into quiescence. Although these events occurred concomitantly, it is unclear how specific changes in gene expression relate to reorganization of the genome at higher resolution. Using computational analyses, genome organization assays and microscopy, the relationship between chromosome territory positioning and gene expression was investigated. We determined that despite relocation of chromosome territories, there was no substantial bias in the proportion of genes changing expression on any one chromosome, including chromosomes 10 and 18. Computational analyses identified that clusters of serum deprivation and rapamycin-responsive genes along the linear extent of chromosomes. Chromosome conformation capture (3C) analysis demonstrated the strengthening or loss of specific long-range chromatin interactions in response to rapamycin and quiescence induction, including a cluster of genes containing Interleukin-8 and several chemokine genes on chromosome 4. We further observed that the LIF gene, which is highly induced upon rapamycin treatment, strengthened interactions with up- and down-stream intergenic regions. Our findings indicate that the re-positioning of chromosome territories in response to cell stimuli, this does not reflect gene expression changes occurring within physically clustered groups of genes.
MicroRNA profiling of human myeloid angiogenic cells derived from peripheral blood mononuclear cells
(Canadian Science Publishing, 2019-07-30) Zhang, Qiuwang; Cannavicci, Anthony; Dai, Si-Cheng; Wang, Chenxi; Kutryk, Michael J
Human myeloid angiogenic cells (MACs), also termed early endothelial progenitor cells, play an important role in neovascularization and vascular repair. MicroRNAs (miRNAs) are a class of naturally occurring, noncoding, short (∼22 nucleotides), single-stranded RNAs that regulate gene expression post-transcriptionally. MiRNAs have been shown to regulate MAC function. A miRNA signature of MACs was described approximately a decade ago, and many new miRNAs have been discovered in recent years. In this study, we aimed to provide an up-to-date miRNA signature for human MACs. MACs were obtained by culture of human peripheral blood mononuclear cells in endothelial medium for 7 days. Using qPCR array analysis we identified 72 highly expressed miRNAs (CT value < 30) in human MACs. RT–qPCR quantification of select miRNAs revealed a strong correlation between the CT values detected by the array analysis and RT–qPCR, suggesting the miRNA signature generated by the qPCR array assay is accurate and reliable. Experimentally validated target genes of the 10 most highly expressed miRNAs were retrieved. Only a few of the targets and their respective miRNAs have been studied for their role in MAC biology. Our study therefore provides a valuable repository of miRNAs for future exploration of miRNA function in MACs.
MicroRNA-24 alleviates isoflurane-induced neurotoxicity in rat hippocampus via attenuation of oxidative stress
(Canadian Science Publishing, 2019-08-23) Li, Na; Yue, Linli; Wang, Jun; Wan, Zhenzhen; Bu, Wenhao
Several miRNAs have been recently suggested as potential therapeutic targets for anesthesia-related diseases. This study was carried out to explore the biological roles of miR-24 in isoflurane-treated rat hippocampal neurons. Isoflurane was used to induce neurotoxicity in a rat model. Gain- and loss-of-function of miR-24 was performed, and the size and Ca2+ permeability of mitochondria, as well as cell proliferation and apoptosis, and levels of oxidative-stress-related factors were measured both in vivo and in vitro. Dual luciferase reporter gene assays were used to identify the target relationship between miR-24 and p27kip1. In this study, isoflurane treatment decreased miR-24 expression, after which, levels of neuron apoptosis and oxidative-stress-related factors were elevated and neuron viability was reduced. Over-expression of miR-24 inhibited oxidative damage and neuronal apoptosis in hippocampal tissues, and suppressed the size and Ca2+ permeability of mitochondria of hippocampal neurons. miR-24 enhanced the viability of rat hippocampal neurons by targeting p27kip1. To conclude, this study demonstrated that miR-24 attenuates isoflurane-induced neurotoxicity in rat hippocampus via its antioxidative properties and inhibiting p27kip1 expression.

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