Yes / Nottingham Trent University, United Kingdom, UoA03 QR and Capital Funds (MIA), as well as by the grant from Amway, USA to VAB and NVB.

Type 2 diabetes mellitus is a growing problem across the world and has significant pathological changes associated with it, including diabetic cardiomyopathy, wherein cardiac function is reduced. MicroRNA-21 has been shown to play a role in both the heart and diabetes so it was thought that knocking out miR-21 could have a protective effect on oxidative phosphorylation function in diabetic mice. Subsarcolemmal and interfibrillar mitochondria were isolated from adult male WT, miR-21 KO, db/db, and double knockout mice (db/db and miR-21 KO cross) and evaluated for function. Knocking out miR-21 in diabetic mice showed a restorative effect in Complex I and Complex II function even though it increased ROS production in Complex I and did not show a significant change in MPTP opening. Knocking out miR-21 could potentially restore oxidative phosphorylation function in diabetic patients but at the expense of producing more ROS.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20073号 / 医博第4166号 / 新制||医||1018(附属図書館) / 33189 / 京都大学大学院医学研究科医学専攻 / (主査)教授 高田 穣, 教授 武藤 学, 教授 武田 俊一 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Prostate cancer is the most commonly diagnosed cancer and the second most leading cause of cancer deaths in American men (www.cancer.org). Most prostate cancer-related deaths are due to the metastatic form of the disease. The 5-year relative survival rate in patient's diagnosed with metastatic prostate cancer is just 28%, as compared to 100% in patient's diagnosed with localized prostate cancer. This clearly indicates the lack of effective treatment available for metastatic prostate cancer. MicroRNAs (miRNAs) are small (18~23 nucleotide long) non-coding RNAs that can influence gene expression by binding to the 3'-untranslated region of coding RNAs at the post-transcriptional level. Some miRNAs has been termed as oncomirs due to their role in promoting tumor growth, invasion and metastasis. One such oncomir is microRNA-21 (miR-21) whose levels are often up-regulated in a number of cancers, including prostate cancer. MiR-21 increases the survival and invasiveness of cancer cells by suppressing its target tumor suppressor genes, namely programmed cell death 4 (PDCD4) and maspin. Thus, drugs which target miR-21 for inhibition could provide novel treatment options for metastatic prostate cancer. Resveratrol (3,5,4'-trihydroxystilbene) is a polyphenolic phytoalexin found in high quantities in various dietary sources, such as grapes, red wine, berries and peanuts. Various reports have demonstrated a significant role of resveratrol in the management of several old age diseases including cancer. The efficacy of resveratrol as an anti-cancer agent resides in its ability to interfere with cell proliferation and metastasis and enhancement of apoptosis. Resveratrol has been shown to act on several intracellular targets to exert these effects. However, the exact mechanism by which resveratrol mediates its beneficial cancer chemotherapeutic actions are not clear and is the focus of this study. Based on the reported data, we hypothesized that resveratrol mediates its anti-cancer action against metastatic prostate cancer by inhibiting the signaling pathway which involves miR-21 expression and function. To address this hypothesis, we show that resveratrol decreased cell viability, migration and invasiveness of androgen-receptor negative and highly aggressive human prostate cancer cells, PC-3M-MM2. These effects of resveratrol were associated with the inhibition of miR-21, since over-expression of miR- 21 with pre-miR-21 oligonucleotides attenuated resveratrol's effect on these cells. Additionally, resveratrol increased the expression of tumor suppressors, PDCD4 and maspin, which are negatively regulated by miR-21 and knockdown of PDCD4 by short interfering (si) RNA reversed the resveratrol's effect on prostate cancer cells. PC-3M-MM2 cells also exhibits high levels of phospho-Akt (pAkt), which were reduced by both resveratrol and LY294002, a known PI3-kinase inhibitor. MiR-21 expression in these cells appears to be dependent on Akt, as LY294002 reduced the levels of miR-21 along with a concurrent increase in PDCD4 expression. These in vitro findings were further corroborated in a severe combined immunodeficient (SCID) mouse xenograft model of prostate cancer. Oral administration of resveratrol not only inhibits the tumor growth but also decreased the incidence and number of metastatic lung lesions. These tumor- and metastatic-suppressive effects of resveratrol were associated with reduced miR-21 and pAkt, and elevated PDCD4 levels. Future investigation into the molecular mechanisms revealed that resveratrol suppressed prostate cancer growth by decreasing the levels of insulin-like growth factor-1 (IGF-1) and its receptor (R). Previous studies had associated elevated levels of serum IGF-1 with high risk of prostate cancer. IGF-1, after binding to its receptors, acts as a potent mitogen which stimulates cancer cell growth and proliferation mainly by activating Akt signaling pathway. Interestingly, this effect of resveratrol on IGF-1/IGF-1R was independent of its effect on miR-21. In summary, our data show that resveratrol exerts its anti-cancer effect on metastatic prostate cancer cells, at least in part, by targeting Akt/miR-21 pathway. These data highlight a potential molecular mechanism for resveratrol's anti-cancer action for the treatment of metastatic prostate cancer and suggest that inhibition of the IGF-1/Akt/miR-21 pathway is a rationale approach for the treatment prostate cancer metastasis.

No / Bone morphogenetic proteins (BMPs) play essential roles in the control of skin development, postnatal tissue remodelling and tumorigenesis. To explore whether some of the effects of BMP signalling are mediated by microRNAs, we performed genome-wide microRNA (miRNA) screening in primary mouse keratinocytes after BMP4 treatment. Microarray analysis revealed substantial BMP4-dependent changes in the expression of distinct miRNAs, including miR-21. Real-time PCR confirmed that BMP4 dramatically inhibits miR-21 expression in the keratinocytes. Consistently, significantly increased levels of miR-21 were observed in transgenic mice overexpressing the BMP antagonist noggin under control of the K14 promoter (K14-noggin). By in situ hybridization, miR-21 expression was observed in the epidermis and hair follicle epithelium in normal mouse skin. In K14-noggin skin, miR-21 was prominently expressed in the epidermis, as well as in the peripheral portion of trichofolliculoma-like hair follicle-derived tumours that contain proliferating and poorly differentiated cells. By transfecting keratinocytes with a miR-21 mimic, we identified the existence of two groups of the BMP target genes, which are differentially regulated by miR-21. These included selected BMP-dependent tumour-suppressor genes (Pten, Pdcd4, Timp3 and Tpm1) negatively regulated by miR-21, as well as miR-21-independent Id1, Id2, Id3 and Msx2 that predominantly mediate the effects of BMPs on cell differentiation. In primary keratinocytes and HaCaT cells, miR-21 prevented the inhibitory effects of BMP4 on cell proliferation and migration. Thus, our study establishes a novel mechanism for the regulation of BMP-induced effects in the skin and suggests miRNAs are important modulators of the effects of growth factor signalling pathways on skin development and tumorigenesis.

Eine angemessene, regelmäßige sportliche Aktivität wirkt protektiv auf die Erhaltung und Wiederherstellung körperlicher und geistiger Gesundheit. Die Herzinsuffizienz ist nicht zuletzt durch ihre hohe Prävalenz ein internistisches Krankheitsbild von enormer Relevanz im klinischen Alltag. Im Rahmen einer bestehenden Herzinsuffizienz kann es zur pathophysiologischen Ausprägung einer gestörten Endothelfunktion kommen, welche sich in einer verringerten endothelialen Dilatationsfähigkeit ausdrücken kann. Das Ziel dieser Dissertation bestand in der Untersuchung der Auswirkungen eines körperlichen Trainings auf die Funktionsleistung der Endothelzellen von herzinsuffizienten Mäusen. Hierzu wurde in einem operativen Eingriff durch die Ligatur des Ramus interventricularis anterior bei jungen Mäusen ein herzinsuffizientes Tiermodell geschaffen und der sekundärpräventive Effekt eines anschließenden zehnwöchigen Laufbandtrainings eruiert. Als Funktionsmaß der Endothelzellen diente dabei ihre endothelabhängige Dilatationsfähigkeit, welche im Organbad erhoben wurde. Weiterhin lag der Fokus auf der Untersuchung des Einflusses der im Endothel exprimierten microRNA-21 und microRNA-126 im trainierten und untrainierten herzinsuffizienten Aortenendothel. Ihre Expression wurde in den verschiedenen Versuchsgruppen quantitativ mittels Real-Time PCR erfasst. In einem weiteren Ansatz bestand das Ziel, den Einfluss einer Angiotensin II- beziehungsweise Zytokinstimulation - als Modell eines mit der Herzinsuffizienz vergesellschafteten Inflammationsgeschehens - auf diese beiden endothelexprimierten microRNAs zu erforschen.

Eine angemessene, regelmäßige sportliche Aktivität wirkt protektiv auf die Erhaltung und Wiederherstellung körperlicher und geistiger Gesundheit. Die Herzinsuffizienz ist nicht zuletzt durch ihre hohe Prävalenz ein internistisches Krankheitsbild von enormer Relevanz im klinischen Alltag. Im Rahmen einer bestehenden Herzinsuffizienz kann es zur pathophysiologischen Ausprägung einer gestörten Endothelfunktion kommen, welche sich in einer verringerten endothelialen Dilatationsfähigkeit ausdrücken kann. Das Ziel dieser Dissertation bestand in der Untersuchung der Auswirkungen eines körperlichen Trainings auf die Funktionsleistung der Endothelzellen von herzinsuffizienten Mäusen. Hierzu wurde in einem operativen Eingriff durch die Ligatur des Ramus interventricularis anterior bei jungen Mäusen ein herzinsuffizientes Tiermodell geschaffen und der sekundärpräventive Effekt eines anschließenden zehnwöchigen Laufbandtrainings eruiert. Als Funktionsmaß der Endothelzellen diente dabei ihre endothelabhängige Dilatationsfähigkeit, welche im Organbad erhoben wurde. Weiterhin lag der Fokus auf der Untersuchung des Einflusses der im Endothel exprimierten microRNA-21 und microRNA-126 im trainierten und untrainierten herzinsuffizienten Aortenendothel. Ihre Expression wurde in den verschiedenen Versuchsgruppen quantitativ mittels Real-Time PCR erfasst. In einem weiteren Ansatz bestand das Ziel, den Einfluss einer Angiotensin II- beziehungsweise Zytokinstimulation - als Modell eines mit der Herzinsuffizienz vergesellschafteten Inflammationsgeschehens - auf diese beiden endothelexprimierten microRNAs zu erforschen.

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and chronic hepatitis B virus (HBV) infection is the major risk factor of HCC. The virus encodes HBV X (HBx) protein that plays a critical role in the development of HCC. Studies have revealed numerous HBx-altered genes and signalling pathways that heavily contribute to tumourigenesis of non-tumour hepatocytes. However, the role of HBx in regulating other critical gene regulators such as microRNAs is poorly understood, which impedes the exploration of a complete HBx-associated carcinogenic network. Besides, critical microRNAs that drive the transformation of non-tumour hepatocytes are yet to be identified. Here, we overexpressed C-terminal truncated HBx protein in a non-tumour hepatocyte cell line MIHA, and measured a panel of cancer-associated miRNAs. We observed that oncogenic miR-21 was upregulated upon ectopic expression of this viral protein variant. HBx-miR-21 pathway was prevalent in HCC cells as inhibition of HBx in Hep3B and PLC/PRF/5 cells significantly suppressed miR-21 expression. Subsequently, we showed that the upregulation of miR-21 was mediated by HBx-induced interleukin-6 pathway followed by activation of STAT3 transcriptional factor. The high dependency of miR-21 expression to HBx protein suggested a unique viral oncogenic pathway that could aberrantly affect a network of gene expression. Importantly, miR-21 was essential in the HBx-induced transformation of non-tumour hepatocytes. Inhibition of miR-21 effectively attenuated anchorage-independent colony formation and subcutaneous tumour growth of MIHA cells. Our study suggested that overexpression of miR-21 was critical to promote early carcinogenesis of hepatocytes upon HBV infection.

No description available.

Yes / Cardiovascular disease is a leading cause of morbidity and mortality. Smooth muscle cells (SMC) comprising the vascular wall can switch phenotypes from contractile to synthetic, which can promote the development of aberrant remodelling and intimal hyperplasia (IH). MicroRNA‐21 (miR‐21) is a short, non‐coding RNA that has been implicated in cardiovascular diseases including proliferative vascular disease and ischaemic heart disease. However, its involvement in the complex development of atherosclerosis has yet to be ascertained. Smooth muscle cells (SMC) were isolated from human saphenous veins (SV). miR‐21 was over‐expressed and the impact of this on morphology, proliferation, gene and protein expression related to synthetic SMC phenotypes monitored. Over‐expression of miR‐21 increased the spread cell area and proliferative capacity of SV‐SMC and expression of MMP‐1, whilst reducing RECK protein, indicating a switch to the synthetic phenotype. Furthermore, platelet‐derived growth factor BB (PDGF‐BB; a growth factor implicated in vasculoproliferative conditions) was able to induce miR‐21 expression via the PI3K and ERK signalling pathways. This study has revealed a mechanism whereby PDGF‐BB induces expression of miR‐21 in SV‐SMC, subsequently driving conversion to a synthetic SMC phenotype, propagating the development of IH. Thus, these signaling pathways may be attractive therapeutic targets to minimise progression of the disease. / King Saud University; College of Medicine , Riyadh, Saudi Arabia