As células glias de Müller são capazes de gerar novos neurônios retinianos em resposta a lesões, atuando como uma possível fonte para regeneração retiniana. Nesse contexto, as GTPases Rho podem ter um papel interessante, visto que regulam múltiplas vias de sinalização que controlam, por exemplo, a transcrição gênica, sobrevivência e proliferação celular. No presente estudo analisamos a participação de um dos membros dessa família (Rac1) na proliferação de células gliais de Müller da retina de galinhas após lesão excitotóxica com N-Metil-D-Aspartato (NMDA). A injeção intraocular de NMDA promoveu extensa proliferação de células gliais de Müller. A inibição de Rac1 com NSC23766 não alterou a quantidade de células que entraram no ciclo celular, mas, provocou um retardo em sua progressão. Esses resultados sugerem um importante papel para a GTPase Rac1 na regulação da proliferação de células gliais de Müller em resposta a lesões retinianas. / Müller glial cells may generate new neurons in response to retinal injury, acting as a potential source for retinal regeneration. In this context, Rho GTPases may have an interesting role, since they regulate multiple signaling pathways that control, for example, gene transcription, cell proliferation and survival. This study analyzed the involvement of a member of this family (Rac1) in the proliferation of Müller glial cells of chick retina after excitotoxic injury with N-methyl-D-aspartate (NMDA). Intraocular injection of NMDA promoted extensive Müller glia proliferation. Rac1 inhibition with NSC23766 did not affect the cell cycle entry, but a delay in cell cycle progression was observed. These results suggest an important role for Rac1 in the regulation of Müller glial cells proliferation in response to retinal injury.

More so than ever, Multiple Drug Resistant (MDR) bacteria are on the rise due to overuse of antibiotics along with natural selection for adaptations that enhance drug-resistant properties. One particular bacterial family, Enterobacteriaceae, has been problematic, exhibiting several bacterial members that have developed a precipitous resistance to modern antibiotics and are also primary causative agents of nosocomial, or hospital acquired, infections. Citrobacter freundii (CF) and Enterobacter cloacae (ECL) are two species of the Enterobacteriaceae family causing significant medical concern due to their role in producing numerous opportunistic infections such as bacteremia, lower respiratory tract infections, urinary tract infections, and endocarditis. Adding to the difficulty of this situation is the ability of bacteria to produce biofilms. These biofilms are communities of bacteria that exhibit increased resistance to antibiotic treatment and eradication. Previous work in the laboratory of Dr. Fox at ETSU has identified an uncharacterized product secreted by Klebsiella pneumoniae (KP), another member of the Enterobacteriaceae family, which appears to have inhibitory effects toward CF and ECL. The current study was designed to characterize the effects this secreted product has on CF and ECL biofilms. Through a high throughput microtiter plate assay, the effects of this secreted product were examined on CF and ECL phases of biofilm attachment and maturation. Based on our findings, we have concluded that this secreted product can be categorized as a possible bacteriostatic agent against biofilm cell density, biofilm mass, and cell viability for both biofilm phases of attachment and maturation.

Significant advances in the efficacy of cancer therapy have been accompanied by an escalation of side effects that result from therapy-induced injury to normal tissues. Patients with high grade cancer or metastasis are often treated with chemotherapy, 50% of which are associated with reactive oxygen species generation and cellular oxidative stress. Heart is the normal tissue most susceptible to chemotherapy-induced oxidative stress and heart disease is the most common leading cause of death in cancer survivors. However, early and sensitive biomarkers to identify heart disease are still lacking. Extracellular vesicles (EVs) are released from cells during oxidative stress and send oxidized proteins into the circulation as a compensatory mechanism that prevents cellular proteotoxicity. Thus, the protein contents of EVs released during the pre-degeneration stage reveal that oxidative stress is occurring early in the damaged tissue. Using a mouse model of doxorubicin (DOX)-induced cardiac injury, we demonstrated that EVs can be used as an early diagnostic tool for tissue injury as they are oxidatively modified with 4-hydroxynonenal and contain tissue specific proteins—glycogen phosphorylase brain/heart, muscle, and liver isoforms—that indicate their origins. These biomarkers increased early, before the changes of conventional biomarkers occurred. EVs also mediate intercellular communication by transferring bioactive molecules between cells. In the cell culture system, EVs play an important role in oxidative stress response by inducing macrophage polarization. EVs from cardiomyocytes promoted both proinflammatory (M1) and anti-inflammatory (M2) macrophage polarization evidenced by higher pro- and anti-inflammatory cytokines and nitric oxide generation, as well as mitochondrial oxidative phosphorylation suppression and glycolysis enhancement. In contrast, EVs from the hepatocytes supported anti-inflammatory macrophage (M2) by enhancing oxidative phosphorylation and anti-oxidant proteins. DOX promoted the immunostimulatory effects of cardiomyocyte EVs but not hepatocyte EVs. The differential functions of EVs on macrophage phenotype switching are due to their different effects on Thioredoxin 1 redox state, which regulates activities of redox sensitive transcription factors NFκB and Nrf-2. Our findings shed light on the role of EVs as a redox active mediator of immune response during chemotherapy.

Cellular senescence a specialized form of growth arrest that contributes to the pathogenesis of several aging-related disorders including cancer. While by definition tumor cells are considered immortalized, they can undergo senescence when exposed to conventional and targeted cancer therapy. Therapy-Induced Senescence (TIS) represents a fundamental response to therapy and impacts its outcomes. However, TIS has been considered a positive therapeutic goal since senescent tumor cells are expected to enter a state of permanent growth abrogation. In this work we examined the hypothesis that a subpopulation of senescent cells can re-acquire proliferative potential after a state of senescent dormancy, indicating that senescence is not obligatorily an irreversible process. Our observations indicate that H460 non-small cell lung cancer cells induced into senescence by exposure to etoposide, and enriched based on β-galactosidase staining and size, were shown to recover reproductive capacity, which was accompanied by resolution of the DNA-damage-response (downregulation of p53 and p21Cip1 induction), attenuation of the Senescence-associated Secretory Phenotype (SASP). To overcome the reservation that the newly dividing cells may not have been derived from the senescent population and in an effort to establish that escape from TIS is feasible, tumor cells induced into senescence by chemotherapy were enriched for senescence by flow cytometry; the subsequent division of senescent cells was demonstrable utilizing both real-time, live microscopy and High Speed Live Cell Interferometry (HSLCI). Furthermore, sorted senescent cells were observed to form tumors when implanted in immune deficient mice and with a significant delay in immunecompetent mice. As chemotherapy induced senescent cells have been identified in patient tumors, it is reasonable to propose that tumor cells that escape from senescence could contribute to disease recurrence. In addition, therapy-induced senescence could prove to reflect one form of tumor dormancy. Recently, ABT263 has been used as a senolytic drug, effectively eliminating senescent cells from aging-related animal models. Here, we utilize ABT263 in a two-hit approach to eliminate senescent tumor cells that persistent after exposure to chemotherapy. ABT263 results in the killing of senescent tumor cells in a concentration-dependent manner and shifts the response towards apoptotic cell death. Furthermore, sequential administration of ABT263 interferes with the ability of senescent tumor cells to recover growth potential. These results indicate that senescent tumor cells can contribute to cancer relapse by acquiring proliferative properties and that senolytic therapy allows for the clearance of dormant senescent tumor cells and will potentially decrease cancer recurrence rates.

Cancer-associated cachexia is a condition defined by a sustained net-negative energy imbalance. Although the different types of adipose tissue – white, beige, and brown – have been implicated in contributing to cancer-associated cachexia, the mechanisms of these maladaptive changes and their impact on whole-body energy expenditure have not been fully elucidated. Using breast cancer as our model, we demonstrate white adipose tissue browning in murine and human breast cancer; furthermore, we demonstrate that this effect is extremely localized and takes place early in tumor progression. We utilized in vitro cell culture techniques and demonstrate that cancer secreted factors and cross-talk with white adipocytes decrease expression of classic white adipose tissue-related genes. We also demonstrate in murine and human culture models that cancer secreted factors reduce white adipocyte lipid droplet size, and cross-talk between cancer cells and adipocytes results in an increase in lipolysis-related gene expression. Interestingly, our results strongly suggest that in mice, neither cancer secreted factors nor cross talk with adipocytes can induce white adipose tissue browning, indicate that this process likely occurs independently of direct cancer interactions with local white adipocytes. We demonstrate that interleukin 6, a cytokine with previous implications in white adipose tissue browning, induces interleukin 6-mediated signaling; however, that signaling alone is not enough to directly induce white adipose tissue browning. We present preliminary data suggesting that immune cell population shifts within the white adipose tissue of mice with breast cancer tumors may be source of white adipose tissue browning. We show that the Virginia Commonwealth University Health System has an identifiable population of patients with cancer with what we hypothesize as maladaptive thermogenic adipose tissue activity, and discuss ongoing experiments aimed at understanding the implications of these changes on whole body energy expenditure in human patients. Lastly, in a case of autoimmune diabetes mellitus in the setting of an extra-adrenal paraganglioma, we demonstrate that the interaction between cancer and whole-body metabolism is multifaceted. Together, these experiments demonstrate that adipose tissue plasticity occurs in breast cancer (and other cancers), and that different drivers for individual changes exist within the tumor microenvironment. We predict that further exploration of the exact mechanisms and translational implications will provide useful information to lead to new therapeutic treatments for patients with cancer-associated cachexia.

Mammalian corneal endothelial cells are considered to be non-proliferative due to the arrest of cells at the G1 phase of the cell cycle. The purpose of this study was to determine whether the down regulation of cyclin dependant kinase inhibitors (p21cip1 and p27kip1) levels by Endothelin-1 (ET-1), would overcome the G1 phase arrest and promote cell cycle progression and proliferation in cultured BCECs (Bovine corneal endothelial cells). BCECs were isolated from bovine corneas and cultured in DMEM supplemented with 10% serum. 5-Bromo 2-deoxy Uridine (BrdU) incorporation was determined in serum starved cultures in 24-well plates as a measure of cell proliferation. Confluent serum starved cells grown in T-25 flasks were treated with 100nM Endothelin-1 in DMEM. The control cells were left untreated in serum free medium. Total cellular protein was isolated using RIPA buffer and quantified according to the Peterson modification of the Lowry method. The level of expression of p21cip1 and p27kip1 proteins relative to β-actin was determined by western blotting technique. Immuno fluorescent localization of p27kip1 was performed using polyclonal anti-p27kip1 and anti-p21cip1 antibodies in confluent and growing cells. An increase in cell proliferation was observed in sub-confluent cultures with Endothelin-1 treatment. This evidence was supported by an increase (~18%) in BrdU incorporation in response to Endothelin-1. Densitometry analysis of immunoblots revealed an increase in the expression of p27kip1 in confluent cell cultures when compared to sub-confluent, dividing cells. p21cip1 was almost undetectable in sub-confluent, actively dividing cultures. Immuno fluorescent analysis revealed that the nuclear staining of p27kip1 was apparently decreased with ET-1 treatment. In conclusion, Endothelin-1 treatment resulted in decrease in p27kip1 and p21cip1 expression in confluent cultures that was greatest at 30 hr of post incubation with Endothelin-1. Endothelin-1 appears to promote cell proliferation. Expression of p27kip1 and p21cip1 was greatly reduced in actively dividing BCECs. Endothelin-1 treatment down-regulated these cyclin dependent kinase inhibitors and may promote cell cycle progression via this mechanism.

As células glias de Müller são capazes de gerar novos neurônios retinianos em resposta a lesões, atuando como uma possível fonte para regeneração retiniana. Nesse contexto, as GTPases Rho podem ter um papel interessante, visto que regulam múltiplas vias de sinalização que controlam, por exemplo, a transcrição gênica, sobrevivência e proliferação celular. No presente estudo analisamos a participação de um dos membros dessa família (Rac1) na proliferação de células gliais de Müller da retina de galinhas após lesão excitotóxica com N-Metil-D-Aspartato (NMDA). A injeção intraocular de NMDA promoveu extensa proliferação de células gliais de Müller. A inibição de Rac1 com NSC23766 não alterou a quantidade de células que entraram no ciclo celular, mas, provocou um retardo em sua progressão. Esses resultados sugerem um importante papel para a GTPase Rac1 na regulação da proliferação de células gliais de Müller em resposta a lesões retinianas. / Müller glial cells may generate new neurons in response to retinal injury, acting as a potential source for retinal regeneration. In this context, Rho GTPases may have an interesting role, since they regulate multiple signaling pathways that control, for example, gene transcription, cell proliferation and survival. This study analyzed the involvement of a member of this family (Rac1) in the proliferation of Müller glial cells of chick retina after excitotoxic injury with N-methyl-D-aspartate (NMDA). Intraocular injection of NMDA promoted extensive Müller glia proliferation. Rac1 inhibition with NSC23766 did not affect the cell cycle entry, but a delay in cell cycle progression was observed. These results suggest an important role for Rac1 in the regulation of Müller glial cells proliferation in response to retinal injury.

Chlamydia is the most reported sexually transmitted infection in the US and is caused by the obligate intracellular bacterium Chlamydia trachomatis. Typically, this presents as a lower genital tract infection (cervicitis or urethritis), but can ascend to the upper genital tract, causing pelvic inflammatory disease, tubal infertility, epididymitis, or ectopic pregnancy. While chlamydia infections can be cured with a single-dose oral antibiotic, repeat infections are common and having multiple chlamydial infections increases a woman’s risk of developing serious chronic conditions. Previous research has shown that estrogen has a positive effect on C. trachomatis infections—an important finding, connecting fluctuating estrogen levels in females to variance in pathogenesis.The mechanism behind this hormonal influence remains unknown; however, previous work in our laboratory indicates that estrogen-stimulated stromal cell effectors play a role in enhancing C. trachomatis infections in a polarized endometrial epithelial Ishikawa (IK)/stromal (SHT-290) cell co-culture model. Specifically, our data indicate that estrogen exposure stimulates osteopontin and vimentin release from stromal cells in co-culture with endometrial epithelial cells. Furthermore, we noted that Chlamydia-infected, polarized Ishikawa cells exposed to a combination of recombinant osteopontin and estrogen released significantly more infectious chlamydia than cultures exposed to estrogen alone. Most tissue culture models being used today employee non-polarized cells. Given the fact that epithelial cell polarization is known to impact C. trachomatis serovar E development, in the current study we sought to determine if the estrogen-induced stromal cell effectors, osteopontin and vimentin, affect C. trachomatis viability and infectivity in non-polarized Ishikawa cells. Non-polarized Ishikawa cells were exposed to osteopontin or vimentin in the presence or absence of estrogen, infected with C. trachomatis serovar E, and collected for examination of chlamydial infectivity and progeny production. Our initial data show that osteopontin and vimentin impact chlamydial progeny production in a concentration dependent fashion, with higher concentrations of recombinant effectors +/- estrogen significantly decreasing progeny production. These data suggest that polarization of host cells influences the way hormone-stimulated effectors interact with the cell to impact on chlamydial infection. Future research goals are to explore other stromal effectors such as fibronectin with estrogen and to study the cell signaling mechanism osteopontin and vimentin use to affect chlamydial infections in polarized epithelial cell cultures.

Developing a tissue-engineered Blood Vessel Mimic (BVM) to represent diabetic macrovascular disease could expedite design of new vascular devices specifically tailored to diabetic patients. In contribution toward this model, this thesis assessed Human Umbilical Vein Endothelial Cell (HUVEC) responses to high glucose conditions. Interleukin 6 (IL-6) and Cluster of Differentiation 36 (CD36) were selected to signify oxidative stress activity, a hallmark of diabetic macrovascular disease. Next, activity of potential reference genes B2M, HPRT1, and ACTB was assessed. All genes were found to exceed acceptable variability, so the E-ΔC T method of data analysis was selected. Next, cellular responses to high glucose treatment at 10.5 mM glucose and 25.5 mM glucose for 7 and 14 days were measured by qPCR. IL-6 mRNA expression increased significantly (p<0.001) following treatment with 25.5 mM glucose at both timepoints. Finally, fluorescent staining for Reactive Oxygen Species (ROS) production and cell viability was performed on HUVECs treated with 10.5- and 25.5-mM glucose for 24 and 48 hours. No differences in ROS production or cell viability were detected due to uncontrolled cell damage during the two-hour staining and imaging procedure. This thesis was limited by low reaction efficiency in qPCR reactions due to mistaken purchasing of primers with included probe-quencher reporters. Measurement of reaction efficiency facilitated valid analysis of data collected using these primers. Imaging experiments were unsuccessful due to a lack of incubation equipment designated for cells undergoing live staining and imaging. Alternative imaging assessments of oxidative stress activity were proposed to circumvent this problem.

Purpose: In an Orthopedic office in Northeast Tennessee clinical decision making about injection options for non-surgical candidates with knee osteoarthritis is unclear. Aims: This quality improvement project will develop a clinical guideline so that providers know criteria for choosing optimal knee alternative treatments for non-surgical knee patients. Outcome measures: An expert panel gave feedback and advice on the information presented for the injection types of Platelet Rich Plasma, Corticosteroids, Amniotic Allograft and Hyaluronic Acid. They edited the guideline then sent the edits back to be complied and edited using the Delphi method. Process and Methods: The expert feedback was then be collected in a non-identifiable fashion and the guideline was rewritten based on the panel advice. Then the guideline was then presented to the practice site and the site reviewed and rated the guideline on clarity, accuracy and ease of use. Results: The guideline was rated by the practice site as able to be adopted into practice and used at the site. Findings and Limitations: Limitations include the practice site is constantly changing and new implementations could be overlooked. The expert panel are all busy professionals and finding time to review and critique a guideline is extensive. Conclusions and Implications: This novel guideline will improve healthcare by eliciting an expert panel of orthopedics that perform injections to assist in compiling the most accurate up to date guideline through which will create enhanced decision making and overall better patient care when choosing knee injections for non surgical patients.