271 |
Notch Regulation of Adam12 Expression in Glioblastoma MultiformeAlsyaideh, Ala'a S. 01 January 2012 (has links) (PDF)
Glioblastoma is the most common malignant brain tumor, accounting for 17% of all primary brain tumors in the United States. Despite the available surgical, radiation, and chemical therapeutic options, the invasive and infiltrative nature of the tumor render current treatment options minimally effective. Recent reports have identified multiple regulators of glioblastoma progression and invasiveness. It has been demonstrated that ADAM12, A Disintegrin And Metalloproteinase encoded by ADAM12 gene, is over-expressed in glioblastoma and directly correlated with tumor proliferation. Additionally, dysregulation of the Notch signaling pathway has been implicated in the pathogenesis of many gliomas. Lastly, an evolving role of microRNAs, small noncoding RNAs, in carcinogenesis is progressively growing. A recent study has identified ADAM12 as a notch-related gene, and another demonstrated that inhibition of notch signaling decreased glioblastoma recurrence. However the mechanisms of regulation are still unknown. In this study, we hypothesize that direct downregulation of microRNA-29, downstream of over-expression of notch enhances glioblastoma malignancy through upregulation of ADAM12. Although our data demonstrate upregulation of Notch1, its downstream target HES1, and ADAM12 in U87MG glioblastoma cell line. Expression of the cleaved intracellular Notch1 was not detected. Furthermore, we were unable to demonstrate an inhibitory effect of ɣ-secretase inhibitor on Notch signaling, likely reflecting the requirement for modifying culturing conditions or detection in our assays. Furthermore, miR-29 was detected in glioblastoma cells. The expression of miR-29 was further elevated by ɣ-secretase inhibitor treatment, suggesting a role for Notch1 inhibition on miR-29 expression. Although no conclusive results are shown in our work, a role of Notch1 through miR-29 is implicated in the pathogenesis of glioblastoma pathogenesis warranting further investigation into the role downstream target genes in the Notch signaling pathway.
|
272 |
Elucidating Mechanisms of Alternative Splicing in Cancer and Cellular StressMontes Serey, Matias Ignacio January 2021 (has links)
No description available.
|
273 |
MiR-128 controls the activity of Polycomb Repressor Complexes 1 and 2 in Neural Stem Cells: Implications of its loss in gliomagenesis.Peruzzi, Pierpaolo 09 August 2013 (has links)
No description available.
|
274 |
HCV-associated Exosomes Promote Myeloid-Derived Suppressor Cell Expansion via Inhibiting miR-124 to Regulate T Follicular Cell Differentiation and FunctionWang, Ling, Cao, Dechao, Wang, Ling, Zhao, Juan, Nguyen, Lam Nhat, Dang, Xindi, Ji, Yingjie, Wu, Xiao Y., Morrison, Zheng D., Xie, Qian, El Gazzar, Mohamed, Ning, Shunbin, Moorman, Jonathon P., Yao, Zhi Q. 11 September 2018 (has links) (PDF)
Virus-infected cells can regulate non-permissive bystander cells, but the precise mechanisms remain incompletely understood. Here we report that this process can be mediated by transfer of viral RNA-loaded exosomes shed from infected cells to myeloid-derived suppressor cells (MDSCs), which in turn regulate the differentiation and function of T cells during viral infection. Specifically, we demonstrated that patients with chronic hepatitis C virus (HCV) infection exhibited significant increases in T follicular regulatory (TFR) cells and decreases in T follicular helper (TFH) cells. These MDSC-mediated T-cell dysregulations resulted in an increased ratio of TFR/TFH and IL-10 production in peripheral blood. Specifically, co-culture of MDSCs derived from HCV patients with healthy peripheral blood mononuclear cells (PBMCs) induced expansion of TFR, whereas depletion of MDSCs from PBMCs of HCV patients reduced the increases in TFR frequency and IL-10 production, and promoted the differentiation of IFN-γ-producing TFH cells. Importantly, we found that exosomes isolated from the plasma of HCV patients and supernatant of HCV-infected hepatocytes could drive monocytic myeloid cell differentiation into MDSCs. These exosomes were enriched in tetraspanins, such as CD63 and CD81, and contained HCV RNA, but exosomes isolated from patients with antiviral treatment contained no HCV RNA and could not induce MDSC differentiation. Notably, these HCV RNA-containing exosomes (HCV-Exo) were sufficient to induce MDSCs. Furthermore, incubation of healthy myeloid cells with these HCV-Exo inhibited the expression of miR−124, whereas reconstitution of PBMCs with miR−124 abolished the effects of HCV−Exo on MDSC induction. Taken together, these results indicate that HCV-associated exosomes can transfer immunomodulatory viral RNA from infected cells to neighboring immune cells and trigger MDSC expansion, which subsequently promotes TFR differentiation and inhibits TFH function. This study reveals a previously unrecognized path that represents a novel mechanism of immune dysregulation during chronic viral infection.
|
275 |
Protection of CD4+ T Cells From Hepatitis C Virus Infection-Associated Senescence via ΔNp63-miR-181a-Sirt1 PathwayZhou, Yun, Li, Guang Y., Ren, Jun P., Wang, Ling, Zhao, Juan, Ning, Shun B., Zhang, Ying, Lian, Jian Q., Huang, Chang X., Jia, Zhan S., Moorman, Jonathan P., Yao, Zhi Q. 27 June 2016 (has links)
T cell dysfunction has a crucial role in establishing and maintaining viral persistence. We have previously shown a decline in miR‐181a, which regulates CD4+ T cell responses via DUSP6 overexpression, in individuals with hepatitis C virus (HCV) infection. Here, we describe accelerated T cell senescence in HCV‐infected individuals compared with age‐ and sex‐matched healthy subjects. Mechanistic studies revealed that up‐regulation of transcription factor ΔNp63 led to the decline of miR‐181a expression, resulting in an overexpression of the antiaging protein Sirt1, in CD4+ T cells from HCV‐infected individuals. Either reconstituting miR‐181a or silencing ΔNp63 or Sirt1 expression in CD4+ T cells led to accelerated T cell senescence, as evidenced by an increased senescence‐associated β‐galactosidase (SA‐β‐gal) expression, shortened telomere length, and decreased EdU incorporation; this suggests that HCV‐induced T cell senescence is counterregulated by the ΔNp63–miR‐181a–Sirt1 pathway. An increase of IL‐2 production was observed in these senescent CD4+ T cells and was driven by a markedly reduced frequency of Foxp3+ regulatory T (Treg) cells and increased number of Foxp3− effector T (Teff) cells upon manipulating the ΔNp63–miR‐181a–Sirt1 pathway. In conclusion, these findings provide novel mechanistic insights into how HCV uses cellular senescent pathways to regulate T cell functions, revealing new targets for rejuvenating impaired T cell responses during chronic viral infection.
|
276 |
Alban Berg as Liedkomponist: An Analytical Study of his Two Settings of "Schliesse mir die Augen beide," 1907 and 1925Ray, Karen, 1951- 05 1900 (has links)
Alan Berg's two musical settings of Theodor Storm's poem"Schliesse mir die Augen beide" have received little in the way of scholarly analytical attention. The three major chapters of this thesis deal with the two settings on three different levels. Chapter II surveys the political and cultural milieu in which Berg functioned as a young composer of Lieder in the years 1900-1910. Chapter III examines the special quality of lyricism which is often attributed to Berg and his works. Chapter IV provides more definitive and complete musical analyses of the two settings than have heretofore been available. The question of what role songwriting played in the development of Berg's compositional process is addressed in the conclusion.
|
277 |
Role of miR-122 in Acetaminophen Induced Liver Injury.Chowdhary, Vivek K. 23 October 2017 (has links)
No description available.
|
278 |
New applications for spectroscopic and chemometric studies of drugs / Neue Anwendungen für spektroskopische und chemometrische Untersuchungen von ArzneimittelnBecht, Alexander Ulrich January 2022 (has links) (PDF)
Spectroscopic methods were established decades ago in a wide variety of fields. This also applies to the pharmaceutical field, although they initially were mostly used for identity testing or structure elucidation only. Technical developments, such as miniaturization (NMR benchtop devices), Fourier transformations (for NMR, MIR spectroscopy) or the combination with chemometric evaluation (e.g., in Process Analytical Technology, PAT), have further increased their importance and opened up new applications. The aim of this work was to investigate further new approaches and to find new applications for already established methods and to show their benefits.
By means of MIR, NIR and NMR data and their chemometric evaluation (principal component analysis, PCA; hierarchical cluster analysis, HCA; linear discriminant analysis, LDA), possibilities were presented to successfully determine the manufacturer or the pharmaceutical company of various paracetamol preparations. In the course of this, various similarities and correlations between the preparations of individual companies could also be identified. For this purpose, a suitable sample preparation was developed for each spectroscopic method, and suitable measurement parameters in order to obtain reproducible spectra for the chemometric evaluation were determined. Furthermore, the results of the two unsupervised methods (HCA, PCA) were compared with each other. The HCA was able to confirm those of the PCA for the very most part. Additionally, through these methods it was possible to characterize many of the preparations based on clusters formed by comparable tablet compositions.
In order to be able to measure unmortared, whole tablets using the NIR spectrometer, an attachment was developed and manufactured using 3D printing. Its functionality was demonstrated by measuring and analyzing the tablets of two different batches of nine paracetamol preparations. The batches were clearly distinguished on the basis of a PCA and a significant difference was also demonstrated by means of statistical tests.
For NMR spectroscopy, a method was developed to obtain optimized "fingerprint" spectra of drug formulations. For this purpose, a 1D DOSY measurement was elaborated, in which the signals of the active ingredient could be filtered out by the appropriate choice of measurement parameters. The chemometric evaluation can thus focus on the remaining signals of the excipients, on the basis of which the preparations of the same API can be distinguished. Especially in the case of formulations that consist largely of active ingredient, data pre processing of the spectra can thus be simplified and greater importance can be assigned to the originally very small excipient signals.
A quantitative 1H NMR method was developed for the comparison of a high field spectrometer (400 MHz) with a benchtop spectrometer (80 MHz) for two finished drugs. It was shown that it is possible to obtain comparable results with both instruments, but that the influence of the excipients on the signals and the lower resolution of the benchtop instrument must be taken into account. Therefore, it was not possible to obtain comparable results without further optimization of the method for one of the active ingredients.
In the investigation of various reactions between APIs and excipients using DOSY, its usefulness as a screening method in stability testing was demonstrated. For this purpose, three different APIs and excipients were stressed together and the reaction mixtures were subsequently measured using DOSY. Based on the translational diffusion coefficient, the reaction products could be identified and distinguished from the active ingredients and the excipients used. The importance of thoughtful processing could also be demonstrated. If all peak heights are selected when evaluating signals split by direct spin spin coupling, this allows the detection of hidden signals as long as not all signals have the same diffusion coefficient. The selective selection of individual peak heights in the case of split signals also enables the evaluation of signals that overlap slightly. However, the limitations of this method were also shown when two signals overlap too much and differ too little in their diffusion coefficients.
Hence, it has been successfully demonstrated in the various projects that the new chemometric approaches, as well as the new applications of already established methods, enable in depth findings and thus have a clear added value. / Spektroskopische Methoden haben sich schon vor Jahrzehnten in den verschiedensten Bereichen etabliert. Dies betrifft auch den pharmazeutischen Bereich, auch wenn sie hier zunächst meist nur zur Identitätsprüfung oder Strukturaufklärung verwendet wurden. Durch technische Weiterentwicklungen, wie Miniaturisierungen (NMR benchtop Geräte), Fourier Transformationen (NMR, MIR) oder die Kombination mit einer chemometrischen Auswertung (z. B. bei Process Analytical Technology, PAT), haben sie weiter an Bedeutung gewonnen, und es wurden neue Einsatzbereiche erschlossen. Das Ziel der vorliegenden Arbeit war es, weitere neue Ansätze zu untersuchen und neue Anwendungen für bereits etablierte Methoden zu finden und deren Mehrwert aufzuzeigen.
Es wurden Möglichkeiten aufgezeigt mittels MIR , NIR und NMR Daten und deren chemometrischen Auswertungen (Hauptkomponentenanalyse, PCA; hierarchische Clusteranalyse, HCA; lineare Diskriminanzanalyse, LDA) erfolgreich den Hersteller bzw. das pharmazeutische Unternehmen verschiedener Paracetamol Präparate zu bestimmen. In diesem Zuge konnten Ähnlichkeiten zwischen Präparaten unterschiedlicher Firmen identifiziert werden. Um dies zu erreichen, wurde für jede spektroskopische Methode eine geeignete Probenvorbereitung entwickelt sowie geeignete Messparameter festgelegt, um reproduzierbare Spektren für die chemometrische Auswertung zu erhalten. Weiterhin wurden die Ergebnisse der zwei unüberwachten Methoden (HCA, PCA) miteinander verglichen, wobei die HCA die der PCA zum allergrößten Teil bestätigen konnte. Zudem war es möglich durch diese Methoden viele der Präparate anhand von Clustern zu charakterisieren, die durch vergleichbare Tablettenzusammensetzungen gebildet wurden.
Um mit Hilfe des NIR Spektrometers intakte Tabletten vermessen zu können, wurde ein Aufsatz entwickelt und mittels 3D Druck hergestellt. Dessen Funktionalität wurde überprüft, indem Tabletten aus je zwei unterschiedlichen Chargen von neun Paracetamol Präparaten vermessen und analysiert wurden. Dabei konnten die Batches anhand einer PCA eindeutig unterschieden und zudem mittels statistischer Tests ein signifikanter Unterschied nachgewiesen werden.
Für die NMR Spektroskopie wurde eine Methode entwickelt, um optimierte „Fingerprint“ Spektren von Arzneimittelformulierungen zu erhalten. Dazu wurde eine 1D DOSY Messmethode erarbeitet, bei der durch die passende Wahl der Messparameter die Signale des Wirkstoffes herausgefiltert werden konnten. Die chemometrische Auswertung konnte sich somit auf die Signale der Hilfsstoffe beschränken, anhand derer die Präparate unterschieden werden können. Vor allem bei Formulierungen, die zum größten Teil aus Wirkstoff bestehen, kann so eine Datenvorverarbeitung der Spektren vereinfacht und den ursprünglich sehr kleinen Hilfsstoffsignalen eine größere Bedeutung beigemessen werden.
Für den Vergleich eines Hochfeld Spektrometers (400 MHz) mit einem „benchtop“ Spektrometer (80 MHz) wurde für zwei Fertigarzneimittel eine quantitative 1H NMR Methode entwickelt. Es konnte gezeigt werden, dass es möglich ist, mit beiden Geräten vergleichbare Ergebnisse zu erzielen. Dabei ist jedoch der Einfluss der Hilfsstoffe auf die Signale sowie die geringere Auflösung des „benchtop“ Gerätes zu berücksichtigen. Aus diesen Gründen war es ohne eine weitere Optimierung der Methode für einen der Wirkstoffe nicht möglich vergleichbare Ergebnisse mit beiden Geräten zu erzielen.
Bei der Untersuchung verschiedener Reaktionen zwischen Wirk- und Hilfsstoffen mittels DOSY konnte dessen Nutzen als Screening Methode bei Stabilitätstests gezeigt werden. Für diesen Zweck wurden drei verschiedene Wirk- und Hilfsstoffe gemeinsam gestresst und die Reaktionsgemische anschließend mittels DOSY vermessen. Anhand des translationalen Diffusionskoeffizienten konnten die Reaktionsprodukte identifiziert und von den eingesetzten Wirk- und Hilfsstoffen unterschieden werden. Ebenso konnte die Bedeutung einer sorgfältigen Prozessierung demonstriert werden. Werden bei der Auswertung von Signalen, die durch direkte Spin Spin Kopplung aufgespalten wurden, alle Peakhöhen ausgewählt, erlaubt dies die Detektion von versteckten Signalen, falls nicht alle Signale den gleichen Diffusionskoeffizienten besitzen. Die selektive Auswahl einzelner Peakhöhen bei aufgespaltenen Signalen ermöglicht zudem die Auswertung von leicht überlappenden Signalen. Es wurden jedoch auch die Grenzen dieser Methode aufgezeigt: wenn zwei Signale zu stark überlappen und sich dabei in ihrem Diffusionskoeffizienten zu wenig unterscheiden.
Somit konnte in den verschiedenen Projekten erfolgreich gezeigt werden, dass die neuen chemometrischen Ansätze, sowie die neuen Anwendungen bereits etablierter Methoden vertiefte Erkenntnisse ermöglichen und somit einen deutlichen Mehrwert besitzen.
|
279 |
NF-kappaB-dependent regulation of the diagnostic marker CD10 and role of BCL-2 activity in histone deacetylase inhibitor-induced apoptosis in human B-lymphoma cell linesThompson, Ryan C. 22 January 2016 (has links)
Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous disease
with multiple distinct molecular subtypes. Increased NF-κB activity and expression of the
microRNA miR-155 (product of the BIC gene) are associated with one subtype, called
the activated B-cell (ABC) subtype. It is shown here that induction of NF-κB activity
leads to increased miR-155 expression, the levels of miR-155 in a panel of B-lymphoma
cell lines correlate with increased NF-κB activity, and the NF-κB p50/p65 heterodimer
binds to a specific DNA site in the BIC promoter. Also described is a regulatory network
wherein NF-κB-dependent up-regulation of miR-155 leads to reduced PU.1 transcription
factor expression and consequently reduced PU.1-driven expression of B-lymphoma
marker CD10 in the human B-lymphoma cell line BJAB.
Genetic variation in DLBCL can be used to explain the response of individual
patients to chemotherapy. One cancer therapeutic approach currently in clinical trials uses
histone deacetylase inhibitors (HDACi's) as a monotherapy or in combination with other
vi
agents. It is shown here that two pan-HDACi's, trichostatin A and vorinostat, induce
apoptosis in seven of eight human DLBCL cell lines. Ectopic over-expression of antiapoptotic
proteins BCL-2 and BCL-XL or the pro-apoptotic protein BIM in select
DLBCL cell lines can confer further resistance or sensitivity, respectively, to HDACi
treatment. Additionally, the BCL-2 family antagonist ABT-737 can increase the
sensitivity of several DLBCL cell lines to vorinostat-induced apoptosis, including the
HDACi-resistant SUDHL6 cell line. Moreover, one vorinostat-resistant variant of the
HDACi-sensitive cell line SUDHL4 has increased expression of anti-apoptotic proteins
BCL-XL and MCL-1 and decreased sensitivity to ABT-737, and a second such variant
cell line has increased expression of anti-apoptotic protein MCL-1. These results suggest
that the balance of anti- to pro-apoptotic BCL-2 family protein expression is important in
determining the sensitivity of DLBCL cell lines to HDACi-induced apoptosis. Thus, the
sensitivity of DLBCL cell lines to treatment with HDACi's appears to depend on the
complex regulation of BCL-2 family members, suggesting that the response of a subset of
DLBCL patients to HDACi treatment may benefit from co-treatment with BCL-2
antagonists.
|
280 |
Therapeutic miR-506-3p Replacement in Pancreatic Carcinoma Leads to Multiple Effects including Autophagy, Apoptosis, Senescence, and Mitochondrial Alterations In Vitro and In VivoBorchardt, Hannes, Kogel, Alexander, Kalwa, Hermann, Weirauch, Ulrike, Aigner, Achim 03 November 2023 (has links)
Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer mortality. Considering its very poor prognosis, novel treatment options are urgently needed. MicroRNAs (miRNAs) are
involved in the regulation of various physiological and pathological processes. In tumors, aberrant
downregulation of given miRNAs may result in pathological overexpression of oncogenes, rendering
miRNA replacement as a promising therapeutic strategy. In different tumor entities, miRNA-506-3p
(miR506-3p) has been ambivalently described as tumor suppressing or oncogenic. In PDAC, miR-506
is mainly considered as a tumor-suppressing miRNA. In this study, we extensively analyze the
cellular and molecular effects of miRNA-506-3p replacement in different PDAC cell lines. Beyond
profound antiproliferation and induction of cell death and autophagy, we describe new cellular
miR506-3p effects, i.e., induction of senescence and reactive oxygen species (ROS), as well as alterations in mitochondrial potential and structure, and identify multiple underlying molecular effects. In
a preclinical therapy study, PDAC xenograft-bearing mice were treated with nanoparticle-formulated
miRNA-506 mimics. Profound tumor inhibition upon systemic miRNA-506 administration was
associated with multiple cellular and molecular effects. This demonstrates miRNA replacement as a
potential therapeutic option for PDAC patients. Due to its broad mechanisms of action on multiple
relevant target genes, miR506-3p is identified as a particularly powerful tumor-inhibitory miRNA.
|
Page generated in 0.0387 seconds