MicroRNA-29与糖尿病及其并发症

小分子RNA(miR)是近年发现的一类广泛存在于动植物中的小分子非编码RNA,它通过抑制靶目标的转录或直接将其降解而发挥作用.miR-29是新近发现的与糖尿病及其并发症有密切关系的一类小分子RNA.研究发现,miR-29可直接参与糖尿病的基本病理生理过程,如参与胰岛素相关信号通路.同时也参与肾脏纤维化、视网膜神经元凋亡等过程,从而在糖尿病肾病、糖尿病视网膜病变等糖尿病并发症的发生中起重要作用.     

Berberine promotes ischemia-induced angiogenesis in mice heart via upregulation of microRNA-29b

Background: Berberine has several preventive effects on cardiovascular diseases. Increased expression of miR-29b has been reported to attenuate cardiac remodeling after myocardial infarction (MI). We hypothesized that berberine via an miR-29b-dependent mechanism promotes angiogenesis and improves heart functions in mice after MI.

Methods: The MI model was established in mice by ligation of left anterior descending coronary artery. The expression of miR-29b was examined by RT-qPCR. Angiogenesis was assessed by immunohistochemistry.

Results: Berberine increased miR-29b expression and promoted cell proliferations and migrations in cultured endothelial cells, which were abolished by miR-29b antagomir or AMP-activated protein kinase inhibitor compound C. In mice following MI, administration of berberine significantly increased miR-29b expressional level, promoted angiogenesis, reduced infarct size, and improved heart functions after 14 postoperative days. Importantly, these in vivo effects of berberine were ablated by antagonism of miR-29b.

Conclusion: Berberine via upregulation of miR-29b promotes ischemia-induced angiogenesis and improves heart functions.     

MicroRNA-29a对血管平滑肌细胞增殖和迁移的影响

目的 研究MicroRNA-29 a对血管平滑肌细胞(VSMC)增殖和迁移的影响并探讨其可能机制.方法 通过MTT法和划痕法分别观察microRNA-29a对VSMCs活力和迁移能力的影响;通过Realtime-PCR和Western印迹检测分别观察micro-RNA-29 a对MMP-9、MMP-2和PCNA表达的影响.结果 与阴性对照组和空白对照组相比较,MicroRNA-29 a反义寡核苷酸组VSMC体外增殖能力和迁移能力明显被抑制(P＜0.05);Realtime-PCR和Western印迹检测发现与阴性对照组和空白对照组相比较,MicroRNA-29 a反义寡核苷酸组MMP-9、MMP-2和PCNA表达明显降低.结论 microRNA-29a可以影响VSMC增殖和迁移,其机制可能是通过调节MMP-9、MMP-2和PCNA的表达来得以实现的.     

DNA甲基转移酶3b和microRNA-29b在胰腺癌细胞株中的表达及其相关性

目的 明确胰腺癌细胞株甲基转移酶( DNMT)3b和microRNA-29b(miR-29b)的表达,分析两者的相关性.方法 应用实时定量PCR法检测人胰腺癌细胞株PANC1、BxPC3、CFPAC、AsPC-1、Capan-2的DNMT3b mRNA和miR-29b表达.采用Pearson直线相关分析法分析两者表达量的相关性.结果 PANC1、BxPC3、CFPAC、AsPC-1、Capan-2的DNMT3b mRNA相对表达量分别为0.497±0.184、0.420±0.168、0.439±0.217、0.122 ±0.111和0.731±0.387;miR-29b的相对表达量分别为0.745±0.596、0.464±0.430、0.797±1.000、1.836±1.623和0.216 ±0.335,DNMT3b mRNA的表达量和miR-29b的表达量呈负相关关系(r=-0.922,P=0.026).结论 DNMT3b和miR-29b均参与了胰腺癌的发生发展,两者呈负相关关系.     

Restoring control

PURPOSE: Anal incontinence is a socially disabling problem affecting 1 to 2 percent of the population. Anal sphincter replacement is a treatment option if the problem is severe and not amenable to direct repair. The artificial bowel sphincter is an innovative approach. We report the technique for placement and the outcomes which have occurred in an initial series of 13 patients. METHODS: The Acticon Neosphincter® artificial bowel sphincter consists of an inflatable cuff of silicone elastomer placed around the anal canal and connected to a pressure-regulating balloon in the iliac fossavia a control pump placed in the labium or scrotum. Thirteen patients with severe anal incontinence not amenable to other methods were treated. Causes of incontinence included obstetric damage in eight patients, surgical damage in two patients, imperforate anus in two patients, and spina bifida in one patient. RESULTS: Surgical placement of the device was straightforward, mean operating time was 65 minutes, and median length of stay was 3.6 days. One infection of the perineal wound occurred in the early postoperative period necessitating removal of the device. In two further patients the artificial bowel sphincter was removed because of late infection in one at seven months and because of erosion through the skin in another at three months. The artificial bowel sphincter has been activated in ten patients resulting in full continence to solids and liquids except in one patient with postvagotomy diarrhea who had some leakage of liquids during episodes of diarrhea. The mean (± standard deviation) continence score (Cleveland Clinic system; maximal incontinence = 20) changed from 18.7 ± 1.6 preoperatively to 2.1 ± 2.6 after activation (P<0.0001). Quality of life measured using a continence-specific series of up to 39 questions changed from 77 ± 16 percent of maximal reduction of quality preoperatively to 12 ± 19 percent postoperatively (P<0.001). CONCLUSIONS: The artificial bowel sphincter can be placed without technical difficulty and with low morbidity. Preliminary experience shows full restoration of continence in most patients and ease of use. Longer follow-up is needed to determine the extent of problems with infection, erosion, and mechanical failure.Read at The American Society of Colon and Rectal Surgeons' 100th Anniversary and Tripartite Meeting, Washington, D.C., May 1 to 6, 1999.     

MicroRNA-29a and microRNA-142-3p are regulators of myeloid differentiation and acute myeloid leukemia

Although microRNAs (miRNAs) are increasingly linked to various physiologic processes, including hematopoiesis, their function in the myeloid development is poorly understood. We detected up-regulation of miR-29a and miR-142-3p during myeloid differentiation in leukemia cell lines and CD34(+) hematopoietic stem/progenitor cells. By gain-of-function and loss-of-function experiments, we demonstrated that both miRNAs promote the phorbol 12-myristate 13-acetate-induced monocytic and all-trans-retinoic acid-induced granulocytic differentiation of HL-60, THP-1, or NB4 cells. Both the miRNAs directly inhibited cyclin T2 gene, preventing the release of hypophosphorylated retinoblastoma and resulting in induction of monocytic differentiation. In addition, a target of miR-29a, cyclin-dependent kinase 6 gene, and a target of miR-142-3p, TGF-β-activated kinase 1/MAP3K7 binding protein 2 gene, are involved in the regulation of both monocytic and granulocytic differentiation. A significant decrease of miR-29a and 142-3p levels and an obvious increase in their target protein levels were also observed in blasts from acute myeloid leukemia. By lentivirus-mediated gene transfer, we demonstrated that enforced expression of either miR-29a or miR-142-3p in hematopoietic stem/progenitor cells from healthy controls and acute myeloid leukemia patients down-regulated expression of their targets and promoted myeloid differentiation. These findings confirm that miR-29a and miR-142-3p are key regulators of normal myeloid differentiation and their reduced expression is involved in acute myeloid leukemia development.     

Serum microRNA-196 and microRNA-200 in pancreatic ductal adenocarcinoma of patients with diabetes mellitus

Background/ObjectivesOur aim was to compare expressions of 6 microRNAs (miRNAs) in patients with pancreatic ductal adenocarcinoma (PAC) and non-cancer patients, moreover according to the presence or absence of diabetes mellitus.MethodsExpressions of miRNA-192, -196, -200, -21, -30 and -423 were measured in 77 patients with PAC and 64 non-cancer patients (34 patients with type 2 DM and 30 control persons). 60 patients with PAC (78%) had DM or prediabetes and it was of new-onset (less than 2 years before the cancer diagnosis) in 44 out of them.ResultsThe expressions of all microRNAs were 1.4–3.7 times higher (significantly) in the PAC group compared to non-cancer patients. No difference was found between PAC diabetic and PAC non-diabetic patients. MicroRNA-200 was significantly higher in PAC patients with significant body weight loss against those without weight loss. Adding miRNA-196 and -200 to the current marker CA 19-9 improved the discriminative ability of the test (compared to CA 19-9 alone).ConclusionMicroRNA-196 and -200 could be used as additional markers in PAC diagnosis.     

Ferroelectric switching of elastin

Ferroelectricity has long been speculated to have important biological functions, although its very existence in biology has never been firmly established. Here, we present compelling evidence that elastin, the key ECM protein found in connective tissues, is ferroelectric, and we elucidate the molecular mechanism of its switching. Nanoscale piezoresponse force microscopy and macroscopic pyroelectric measurements both show that elastin retains ferroelectricity at 473 K, with polarization on the order of 1 μC/cm², whereas coarse-grained molecular dynamics simulations predict similar polarization with a Curie temperature of 580 K, which is higher than most synthetic molecular ferroelectrics. The polarization of elastin is found to be intrinsic in tropoelastin at the monomer level, analogous to the unit cell level polarization in classical perovskite ferroelectrics, and it switches via thermally activated cooperative rotation of dipoles. Our study sheds light onto a long-standing question on ferroelectric switching in biology and establishes ferroelectricity as an important biophysical property of proteins. This is a critical first step toward resolving its physiological significance and pathological implications.Ferroelectricity was first discovered in synthetic materials in 1920 when spontaneous polarization of Rochelle salt was found to be switchable by an external electric field (1). Ferroelectrics thus belongs to a larger class of pyroelectric materials that possess a unique polar axis, which, in turn, belongs to piezoelectrics exhibiting linear coupling between electric and mechanical fields (2). Because of these versatile properties, ferroelectric materials are promising for a wide range of technological applications in data storage, sensing, actuation, energy harvesting, and electro-optic devices (3). Biological tissues, such as bones and tendons, were first observed to be piezoelectric in 1950s (4), and shortly thereafter, pyroelectricity was discovered in a variety of biological materials as well (5, 6). Ever since then, ferroelectricity has been speculated for biological systems, and its potential physiological significance has been suggested (7). For example, it was hypothesized that the conformation transition in voltage-gated ion channels is ferroelectric in nature (8, 9). Nevertheless, indication of ferroelectricity in biological materials has only recently emerged from nanoscale piezoresponse force microscopy (PFM) studies (10–13).This work is motivated by our recent observation of PFM switching in elastin (12), which has generated quite a bit of excitement, although there is still considerable skepticism regarding the notion of biological ferroelectricity. Such reservation is understandable, given the unusual phenomenon of ferroelectric switching in biology, some ambiguities associated with PFM hysteresis, and a current lack of understanding of the basic science underpinning the switching mechanism. Indeed, there is neither macroscopic evidence of ferroelectric switching nor microscopic understanding of its molecular origin. The current work seeks to address these aforementioned issues, and thus to advance our understanding of biological ferroelectricity on two important fronts. First, we present macroscopic observation of ferroelectric switching in a biological system, derived from careful pyroelectric measurement. This dataset, in our view, decisively settles the long-standing question regarding ferroelectricity in biology. Furthermore, in close conjunction with experiments, we present a molecular-based computational study to elucidate the origin and mechanism underpinning ferroelectric switching of elastin. We show that the polarization in elastin is intrinsic at the monomer level, analogous to the unit cell level polarization in classical perovskite ferroelectrics. Our findings thus establish ferroelectricity as an important biophysical property of proteins, and we believe this is a critical first step toward resolving its physiological significance and pathological implications.     

Restoring allosterism with compensatory mutations in hemoglobin.

Abnormal human hemoglobins (HBs) with amino acid substitutions in the alpha 1 beta 2 interface have very high oxygen affinity and greatly reduced cooperativity in O2 binding compared to normal human Hb. In such abnormal Hbs with mutations at position beta 99, the intersubunit hydrogen bonds between Asp-beta 99 and Tyr-alpha 42 and between Asp-beta 99 and Asn-alpha 97 are broken, thus destabilizing the deoxyquaternary structure of these Hbs. A molecular dynamics method has been used to design compensatory amino acid substitutions in these Hbs that can restore their allosteric properties. We have designed a compensatory mutation in a naturally occurring mutant Hb, Hb Kempsey (Asp-beta 99-->Asn), and have produced it using our Escherichia coli expression plasmid pHE2. We have determined the O2 binding properties of this recombinant double mutant Hb, Hb(Asp-beta 99-->Asn and Tyr-alpha 42-->Asp) and have used 1H NMR spectroscopy to investigate the tertiary structures around the heme groups and the quaternary structure in the alpha 1 beta 2 subunit interface. Our results clearly show that the Tyr-alpha 42-->Asp replacement can substantially compensate for the functional defect of Hb Kempsey caused by the Asp-beta 99-->Asn substitution. The structural and functional information derived from this recombinant Hb provides insights into the structural basis of allosterism and the design of compensatory amino acid substitutions to restore the functional properties of other abnormal HBs associated with hemoglobinopathies.     

胃癌组织微RNA-539和微RNA-4317表达及其与预后的关系

为探讨胃癌组织中miRNA-539和miRNA-4317的表达和两者对胃癌患者预后的预测价值,选择2014年3月1日至2017年12月31日于儋州市人民医院行胃癌根治性切除术治疗的胃癌患者115例,检测其胃癌组织和相应癌旁正常组织(距离癌组织边缘>3 cm)中miRNA-539和miRNA-4317的表达水平,并分析两...     

微RNA-29家族降解PTEN mRNA促进非小细胞肺癌细胞存活与淋巴结侵袭

目的:探索微RNA(microRNA,miRNA/miR)-29家族对淋巴结侵袭性非小细胞肺癌(non-small cell lung cancer,NSCLC)细胞增殖、侵袭的影响及潜在的分子机制.方法:TCGA数据库分析磷酸酶和张力蛋白同源基因(phosphatase and tension homology de...     

Tumor cell interactions with elastin: implications for pulmonary metastasis

Elastin surrounds microvessels in the pulmonary circulation and may pose a barrier to the extravasation of metastatic tumor cells. We find that lung-colonizing murine melanoma cells produce an enzymatic activity that degrades elastin. In addition, the elastin fragments liberated by enzymatic digestion of insoluble elastin stimulate tumor cell chemotaxis. Chemotactic activity is associated with other forms of soluble elastin, including alpha-elastin and tropoelastin. Val-Gly-Val-Ala-Pro-Gly, a synthetic peptide that is a repeat sequence in the elastin molecule, also displayed tumor cell chemotactic activity. The ability to degrade elastin and to migrate in response to soluble elastin peptides is not a property of all tumor cells, but it is most commonly found associated with metastatic tumor cells that colonize pulmonary tissue. We postulate that the ability to migrate in response to elastin fragments may facilitate tumor cell invasion of elastin-rich pulmonary tissue.     

Changes of microRNA-1 and microRNA-21 in human atrial fibrillation

Objectives To investigate changes of microRNA- 1(miR-1) and microRNA-21(miR-21) expressions in human atrial fibrillation(AF).Methods Right atrial appendages were obtained from 12 rheumatic valvular heart disease patients with sinus rhythm(SR)and 14 patients with chronic AF.Quantitative real time polymerase chain reaction(qRT-PCR) was applied to assess expressions of miR-1 and miR- 21.Immunohistochemistry was used to evaluate Kir2.1 expression and masson staining was used to estimate collagen deposition.Results Expressions of miR-1 was decreased (relative expression:0.68±0.09 vs.1.76±0.15,PmiR-21 was increased(relative expression:2.23±0.31 vs.0.94±0.24 vs. 0.043±0.005 vs.8.3±0.01;PmiR-l was negatively correlated to that of left atrium diameters(r=-0.47,P=0.02).Expression of miR-21 was positively correlated to collagen content (r=0.45,P<0.01).Conclusions Expression of miR-1 was down-regulated in AF patients,which may be associated with the increase in Kir2.1.miR-21 level was significantly up-regulated, which may contribute to the increase in collagen content in the atrium.