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The Development of a Plant-Expressed M2e-Based Universal Influenza Vaccine

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Influenza is a deadly disease for which effective vaccines are sorely lacking. This is largely due to the phenomena of antigenic shift and drift in the influenza virus's surface proteins, hemagglutinin (HA) and neuraminidase (NA). The ectodomain of the matrix

Influenza is a deadly disease for which effective vaccines are sorely lacking. This is largely due to the phenomena of antigenic shift and drift in the influenza virus's surface proteins, hemagglutinin (HA) and neuraminidase (NA). The ectodomain of the matrix 2 protein (M2e) of influenza A, however, has demonstrated high levels of conservation. On its own it is poorly immunogenic and offers little protection against influenza infections, but by combining it with a potent adjuvant, this limitation may be overcome. Recombinant immune complexes, or antigens fused to antibodies that have been engineered to form incredibly immunogenic complexes with one another, were previously shown to be useful, immunogenic platforms for the presentation of various antigens and could provide the boost in immunogenicity that M2e needs to become a powerful universal influenza A vaccine. In this thesis, genetic constructs containing geminiviral replication proteins and coding for a consensus sequence of dimeric M2e fused to antibodies featuring complimentary epitopes and epitope tags were generated and used to transform Agrobacterium tumefaciens. The transformed bacteria was then used to cause Nicotiana benthamiana to transiently express M2e-RICs at very high levels, with enough RICs being gathered to evaluate their potency in future mouse trials. Future directions and areas for further research are discussed.

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2018-05

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CXCL10-Induced Migration of Triple-Negative Breast Cancer Cells

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Inhibitor of growth factor 4 (ING4) is a tumor suppressor of which low expression has been associated with poor patient survival and aggressive tumor progression in breast cancer. ING4 is characterized as a transcription regulator of inflammatory genes. Among the

Inhibitor of growth factor 4 (ING4) is a tumor suppressor of which low expression has been associated with poor patient survival and aggressive tumor progression in breast cancer. ING4 is characterized as a transcription regulator of inflammatory genes. Among the ING4-regulated genes is CXCL10, a chemokine secreted by endothelial cells during normal inflammation response, which induces chemotactic migration of immune cells to the site. High expression of CXCL10 has been implicated in aggressive breast cancer, but the mechanism is not well understood. A potential signaling molecule downstream of Cxcl10 is Janus Kinase 2 (Jak2), a kinase activated in normal immune response. Deregulation of Jak2 is associated with metastasis, immune evasion, and tumor progression in breast cancer. Thus, we hypothesized that the Ing4/Cxcl10/Jak2 axis plays a key role in breast cancer progression. We first investigated whether Cxcl10 affected breast cancer cell migration. We also investigated whether Cxcl10-mediated migration is dependent on ING4 expression levels. We utilized genetically engineered MDAmb231 breast cancer cells with a CRISPR/Cas9 ING4-knockout construct or a viral ING4 overexpression construct. We performed Western blot analysis to confirm Ing4 expression. Cell migration was assessed using Boyden Chamber assay with or without exogenous Cxcl10 treatment. The results showed that in the presence of Cxcl10, ING4-deficient cells had a two-fold increase in migration as compared to the vector controls, suggesting Ing4 inhibits Cxcl10-induced migration. These findings support our hypothesis that ING4-deficient tumor cells have increased migration when Cxcl10 signaling is present in breast cancer. These results implicate Ing4 is a key regulator of a chemokine-induced tumor migration. Our future plan includes evaluation of Jak2 as an intermediate signaling molecule in Cxcl10/Ing4 pathway. Therapeutic implications of these findings are targeting Cxcl10 and/or Jak2 may be effective in treating ING4-deficient aggressive breast cancer.

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2019-05

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DNA Origami as Novel Immune Adjuvants

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Cytokines induced by inflammasome has been used for blood cancer treatments, yet these treatments have been less successful in the solid tumor microenvironment. Here precise-morphology DNA origami structures were implemented to accurately test the effect and mechanism of activation in

Cytokines induced by inflammasome has been used for blood cancer treatments, yet these treatments have been less successful in the solid tumor microenvironment. Here precise-morphology DNA origami structures were implemented to accurately test the effect and mechanism of activation in the NLRP3 inflammasome. THP1 WT cells, a macrophage cell line, were treated with eleven different DNA origami structures. The inflammasome activation of two cytokines, Interleukin 1 beta (IL-1β) and Interferon beta (IFN-β), was measured using HEK Blue IL-1β cells, HEK Blue IFN-β cells, and enzyme linked immunosorbent assay (ELISA). Differences in activation signaling have the potential to provide the characterization required to address the intrinsic complexity of modulating an immune response. It is hoped that DNA origami will help induce more inflammation for solid tumors. The DNA origami was tested in three different volumes: 1 μL, 5 μL, and 10 μL. Overall, the origami that showed promising results were Mg Square. Tetrahedral and P53 block also showed potential but not as well as Mg square. Further testing of more DNA origami structures and testing them in mice are key to the success of targeted cancer immunotherapies in the neoadjuvant setting.

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2019-05

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Measuring the Activity of Φ29 DNA Polymerase

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The major goal of this large project is to develop a Recognition Tunneling Nanopore (RTP) device that will be used for determining the structure of glycosaminoglycans (GAGs). The RTP device is composed of a recognition tunneling junction that is embedded

The major goal of this large project is to develop a Recognition Tunneling Nanopore (RTP) device that will be used for determining the structure of glycosaminoglycans (GAGs). The RTP device is composed of a recognition tunneling junction that is embedded in a nanopore. In order to translocate the GAG molecule through the nanopore, researchers have designed a scheme in which the GAG molecule of interest will be attached to the 5’ end of a DNA primer (figure 1) and the DNA primer will be extended by a biotinylated Φ29 DNA polymerase that is anchored in the nanoslit using streptavidin. This research project specifically is part of a larger project with the main goal of comparing the activity of the wild-type Φ29 DNA polymerase which I have expressed and purified with the mutated Φ29 DNA polymerase devoid of 3’ - 5’ exonuclease activity which was made by Dr. Deng.

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2018-05

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Analysis of the Cellular Localization of PANK2 Mutations Using a Yeast Model

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Pantothenate kinase-associated neurodegeneration, PKAN, is a neurological disease that is caused by biallelic mutations in the PANK2 gene, which codes for a pantothenate kinase. Some PANK2 mutations that cause PKAN retain enzymatic activity. A possible explanation for the mutations that

Pantothenate kinase-associated neurodegeneration, PKAN, is a neurological disease that is caused by biallelic mutations in the PANK2 gene, which codes for a pantothenate kinase. Some PANK2 mutations that cause PKAN retain enzymatic activity. A possible explanation for the mutations that have residual activity but still cause the disease is that they do not have the correct cellular localization. The localization of PANK2 was studied through cellular fractionation. We found the precursor form of PANK2, pPANK2, appears to be anchored to the inner membrane of the mitochondria, and the mature form, mPANK2, is located in the inter-membrane space, IMS. However, the IMS of the PKAN causing mutants is completely devoid of mPANK2 which suggests some disease-causing mutations may be mislocalized. In addition, PANK2 catalyzes the first and rate limiting step in Coenzyme A biosynthesis, and in other studies, it has been shown that the CoA biosynthesis enzymes form a complex in yeast. Therefore, we also considered the possibility that PKAN-causing mutations that retain activity have altered interactions with the other CoA biosynthesis enzymes. Coimmunoprecipitation of the proteins in the pathway was done to determine if there were any interactions with PANK2. The results indicate that PANK2 does not directly interact with either PPCS or CoASY, the second and final enzymatic activities in the CoA biosynthesis pathway.

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2019-05

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Characterizing p53REs in the Human Hairless Gene Promoter and 5' Untranslated Region

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The human hairless gene (HR) encodes a 130 kDa transcription factor that is primarily expressed in the brain and skin. In the promoter and 5'-untranslated regions (5'-UTR) of HR, there are three putative consensus p53 responsive elements (p53RE). p53 is

The human hairless gene (HR) encodes a 130 kDa transcription factor that is primarily expressed in the brain and skin. In the promoter and 5'-untranslated regions (5'-UTR) of HR, there are three putative consensus p53 responsive elements (p53RE). p53 is a tumor suppressor protein that regulates cell proliferation, apoptosis, and other cell functions. The p53 protein, a known tumor suppressor, acts as a transcription factor and binds to DNA p53REs to activate or repress transcription of the target gene. In general, the p53 binding sequence is 5'-RRRCWWGYYY-3' where W is A or T, and R and Y are purines or pyrimidines, respectively. However, even if the p53 binding sequence does not match the consensus sequence, p53 protein might still be able to bind to the response element. The intent of this investigation was to identify and characterize the p53REs in the promoter and 5'-UTR of HR. If the three p53REs (p53RE1, p53RE2, and p53RE3) are functional, then p53 can bind there and might regulate HR gene expression. The first aim for this thesis was to clone the putative p53REs into a luciferase reporter and to characterize the transcription of these p53REs in glioblastoma (U87 MG) and human embryonic kidney (HEK293) cell lines. Through the transactivation assay, it was discovered that p53REs 2 and 3 were functional in HEK293, but none of the response elements were functional in U87 MG. Since p53 displayed a different regulatory capacity of HR expression in HEK293 and U87 MG cells, the second aim was to verify whether the p53REs are mutated in GBM U87 MG cells by genomic DNA sequencing.

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2018-05

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Muscle IGF-1 Regulation in Humans with Obesity

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Objective: Isoforms of insulin-like growth factor-1 (IGF-1) gene encodes different IGF-1 isoforms by alternative splicing, and which are known to play distinct roles in muscle growth and repair. These isoforms in humans exist as IGF-1Ea, IGF-1Eb and IGF-1Ec (the latter

Objective: Isoforms of insulin-like growth factor-1 (IGF-1) gene encodes different IGF-1 isoforms by alternative splicing, and which are known to play distinct roles in muscle growth and repair. These isoforms in humans exist as IGF-1Ea, IGF-1Eb and IGF-1Ec (the latter is also known as mechano-growth factor). We sought to determine whether mRNA expression of any of these isoforms is impaired in skeletal muscle of humans with obesity, and given that humans with obesity display reduced protein synthesis in muscle. Methods: We studied 10 subjects (3 females/7 males) with obesity (body mass index: 34 ± 1 kg/m2) and 14 subjects (6 females/8 males) that were lean (body mass index: 24 ± 1 kg/m2) and served as controls. The groups represented typical populations of individuals that differed (P < 0.05) in body fat (obese: 32 ± 2; lean: 22 ± 2) and insulin sensitivity (Matsuda insulin sensitivity index, obese: 5 ± 1; lean 11 ± 2). Total RNA was extracted from 20-30 mg of tissue from muscle biopsies performed after an overnight fast. Isolated RNA was used to perform cDNA synthesis. Real-time PCR was performed using predesigned TaqMan® gene expression assays (Thermo Fisher Scientific Inc) for IGF-1Ea (assay ID: Hs01547657_m1), IGF-1Eb (assay ID: Hs00153126_m1) and IGF-1Ec (assay ID: Hs03986524_m1), as well as ACTB (assay ID: Hs01060665_g1), which was used to adjust the IGF-1 isoform mRNA expression. Responses for mRNA expression were calculated using the comparative CT method (2-ΔΔCT). Results: IGF-1Eb mRNA expression was lower in the subjects with obesity compared to the lean controls (0.67 ± 0.09 vs 1.00 ± 0.13; P < 0.05) but that of IGF-1Ea (0.99 ± 0.16 vs 1.00 ± 0.33) or IGF-1Ec (0.83 ± 0.14 vs 1.00 ± 0.21) were not different between groups (P > 0.05). Conclusions: Among the IGF-1 mRNA isoforms, IGF-1Eb mRNA is uniquely decreased in humans with obesity. Lower IGF-1Eb mRNA expression in muscle of humans with obesity may explain the lower protein synthesis observed in these individuals. Furthermore, these findings may have direct implications for muscle growth and repair in humans with obesity.

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2019-05

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Characterizing the Mechanism of Action of a Potential Targeted Therapy, Triptolide, in Small Cell Carcinoma of the Ovary

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Small cell carcinoma of the ovary (SCCOHT) is a rare ovarian cancer affecting young women and characterized by mutation in SMARCA4 and silencing of SMARCA2, two tumor suppressors that function as ATPases in the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex.

Small cell carcinoma of the ovary (SCCOHT) is a rare ovarian cancer affecting young women and characterized by mutation in SMARCA4 and silencing of SMARCA2, two tumor suppressors that function as ATPases in the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex. SCCOHT patients face a 5-year survival rate of only 26%, but recently we have identified sensitivity of SCCOHT models to a natural product, triptolide. This study aims to ascertain the mechanism of action of triptolide. Previous SCCOHT epigenetic drug research has shown that some drugs reverse SMARCA2 epigenetic silencing to inhibit tumor growth, therefore it is hypothesized that triptolide acts the same and restores SWI/SNF function. Cells treated with triptolide have no change in SMARCA2 expression, suggesting that re-expression of epigenetically silenced tumor suppressor gene does not underlie its mechanism of action. Growth rates following triptolide treatment were observed in the presence and absence of SMARCA4, but no difference in sensitivity was observed. Thus, it is not likely that triptolide acts by restoring SWI/SNF. Others have observed that triptolide acts on xeroderma pigmentosa type B protein (XPB), a component of super-enhancers, which are DNA regions with high levels of transcription that regulate genes responsible for cell identity and oncogenes driving tumorigenesis. Both SCCOHT-1 and BIN67 cell lines treated with triptolide displayed lower expression of the super-enhancer associated MYC oncogene compared to untreated cells, supporting the theory that triptolide could be inhibiting super-enhancers regulating oncogenes.. A western blot confirmed reduced protein levels of RNA polymerase II and bromodomain 4 (BRD4), two essential components found at high levels at super-enhancers, in BIN67 cells treated with triptolide. ChIP-sequencing of Histone H3 Lysine-27 Acetylation (H3K27ac) marks in BIN67 and SCCOHT-1 cell lines identified super-enhancers in SCCOHT using tools CREAM and ROSE, which were mapped to neighboring genes associated genes and compared with the COSMIC database to identify oncogenes, of which the top 11 were examined by qRT-PCR to ascertain whether triptolide reduces their expression. It has been found that 6 out of 11 of the oncogenes examined (SALL4, MYC, SGK1, HIST1H3B, HMGA2, and CALR) decreased in expression when treated with triptolide. Thus, there is reason to believe that triptolide’s mechanism of action is via inhibition of super-enhancers that regulate oncogene expression.

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2020-05

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Analysis of the prrAB two-component system regulatory effects on the lipid profile of Mycobacterium smegmatis

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The prrAB two-component system has been shown to be essential for viability in Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. To study this system, several prrAB mutants of Mycobacterium smegmatis, a close relative of Mtb, were created for study.

The prrAB two-component system has been shown to be essential for viability in Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. To study this system, several prrAB mutants of Mycobacterium smegmatis, a close relative of Mtb, were created for study. These mutants included a deletion mutant complemented with prrA from Mtb controlled by Pmyc1_tetO, a deletion mutant, and a deletion mutant complemented with prrAB from M. smegmatis controlled by the native prrAB promoter sequence (~167 bp upstream sequence of prrAB). In a previous study, the prrAB deletion mutant clumped excessively relative to the wild-type strain when cultured in a nitrogen-limited medium. To address this irregularity, the lipid profiles of these mutants were analyzed through several experimental methods. Untargeted lipidomic profiles were analyzed by Electrospray Ionization Mass Spectrometry (ESI-MS). The ESI-MS data suggested the deletion mutant accumulates triacylglycerol species relative to the wild-type strain. This data was verified by thin-layer chromatography (TLC) and densitometry of the TLC images. The mycolic acid profile of each mutant was also analyzed by TLC but no noteworthy differences were found. High-throughput RNA-Seq analysis revealed several genes involved in lipid biosynthetic pathways upregulated in the prrAB deletion mutant, thus corroborating the ESI-MS and TLC data.

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2017-05

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CHALLENGES IN THE EXPRESSION AND PURIFICATION OF INTERCELLULAR ADHESION MOLECULE- 1

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The Intercellular Adhesion Molecule-1 (ICAM-1, known as CD54) is a cell surface type I transmembrane glycoprotein with a molecular weight of 85 to 110 kDa. The primary function of ICAM-1 is to provide adhesion between endothelial cells and leukocytes after

The Intercellular Adhesion Molecule-1 (ICAM-1, known as CD54) is a cell surface type I transmembrane glycoprotein with a molecular weight of 85 to 110 kDa. The primary function of ICAM-1 is to provide adhesion between endothelial cells and leukocytes after injury or stress. ICAM-1 is used as a receptor for various pathogens such as rhinoviruses, coxsackievirus A21 and the malaria parasite Plasmodium falciparum. ICAM-1 contains five immunoglobulin (Ig) domains in its long N-terminal extracellular region, a hydrophobic transmembrane domain, and a small C-terminal cytoplasmic domain. The Ig domains 1-2 and Ig domains 3-4-5 have been crystallized separately and their structure solved, however the full ICAM-1 structure has not been solved. Because ICAM-1 appears to be important for the mediation of cell-to-cell communication in physiological and pathological conditions, gaining a structural understanding of the full-length membrane anchored ICAM-1 is desirable. In this context, we have transiently expressed a plant-optimized gene encoding human ICAM-1 in Nicotiana benthamiana plants using the MagnICON expression system. The plant produced ICAM-1 is forming aggregates according to previous data. Thus, the current extraction and purification protocols have been altered to include TCEP, a reducing agent. The protein was purified using TALON metal affinity resin and partially characterized using various biochemical techniques. Our results show that there is a reduction in aggregation formation with the use of TCEP.

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2015-05