MEDICA@MUSC (Medical University of South Carolina)
Not a member yet
1558 research outputs found
Sort by
Mechanisms Underlying the Generation of T Cell Stemness and Metabolic Fitness for Adoptive Transfer Therapy Against Solid Tumors
No full textHalf of melanoma patients experience objective responses when treated with adoptive T cell transfer (ACT) therapy. Despite clinical success, there remain barriers in sustained tumor immunity in some patients. Positive therapeutic outcomes with ACT therapy in patients with melanoma are correlated with infusion of less differentiated T cell products. T cell bioenergetic fitness is tightly associated with ‘stemness’ and is denoted by maintenance of mitochondrial mass and respiration capacity in the tumor. Furthermore, PI3Kδ signaling has been associated with T cell differentiation and loss of mitochondrial fidelity. We hypothesized that PI3Kδ inhibition would generate stem-like memory T cells (TSCM) that provide protection against melanoma by enhancing mitochondrial bioenergetics. To test this idea, we expanded melanoma specific CD8+ T cells in the presence of increasing concentrations of Idelalisib, a PI3Kδ specific inhibitor, and infused them into melanoma bearing mice to test antitumor activity. In vitro we tested T cell stemness by flow cytometry and RNA sequencing. We next assessed mitochondrial qualities such as mass, membrane potential, reactive oxygen species, and respiratory capacity. Mitochondrial transcription was measured via mitochondrial mRNA relative quantification and protein levels of electron transport chain proteins. We found that Idelalisib treatment enriches stemness features in T cells that have potent antitumor activity in melanoma. The adoptively transferred T cells transcriptionally resembled TSCM cells. Metrics of improved bioenergetic fitness were elevated in a dose dependent manner. Moreover, mitochondrially encoded electron transport chain gene expression was selectively enhanced at the RNA and protein level. RNA-seq identified REXO2 as a differentially expressed gene, a novel regulator of mitochondrial transcription. Ablation of REXO2 using CRISPR-Cas9 vastly impaired the antitumor activity of stem-like memory T cells. Furthermore, we found Tcf-1 and Lef-1 functioned as transcriptional regulators of REXO2. Our findings indicate that long-lasting tumor immunity of adoptively stem-like memory T cells can be induced in vitro by blocking PI3Kδ. We also discovered a unique role for REXO2 in mitochondrial transcription and TSCM mediated tumor immunity. These findings suggest that modulating mitochondrial transcription is a potential target to bolster the activity of tumor specific T cells and is independent of their stemness qualities
The Impact of County Level Characteristics on Type 2 Diabetes Related ED Utilization
Get PDFApproximately 90-95% of the more than 37 million American adults who are living with diabetes have type 2 diabetes. Additionally, those living in rural areas face poor health outcomes related to chronic diseases such as diabetes. The impact of factors related to social determinants of health such as the role of rurality and social vulnerability were described by examining county diabetes related Emergency Department (ED) visit rates for adults aged 18-25 living in North Carolina. No difference in county level diabetes related ED visits were observed between rural counties vs. nonrural counties in the state. However, patterns did emerge in county level diabetes related ED visit rates. Higher ED visit rates were observed in counties having a social vulnerability index (SVI) of 90% or greater, indicating high social vulnerability. Therefore, future research should focus on factors contributing to higher ED visit rates for this study population living high SVI counties which could lead to policy development and targeted health programming
Strategies to Control Alternative Pathway Activation in Dual Sensory Loss
No full textDual sensory loss is defined as a combination of age-related vision loss, e.g., age-related macular degeneration (AMD), and age-related hearing loss (ARHL), that co-occurs in people aged \u3e65 years. Dry and wet forms of AMD and ARHL share etiologies such as smoking and complement dysregulation. Controlling the complement alternative pathway (AP) amplification loop is crucial, as it causes the majority of complement activation on cell surfaces and extracellular membranes. AP is inhibited by circulating complement protein factor H (fH). Additionally, natural antibodies (nAbs) binding to neoepitopes on damaged tissues in response to injury can activate complement. Complement effector molecules and nAbs have been shown to be elevated in the subretinal space of wet AMD, smoke-induced ocular damage, and the cochlear tissues of aged mouse models where they activate macrophages and intensify the inflammatory state leading to neurodegeneration. In this project, two well-studied fusion proteins, CR2-fH and B4-scFv-fH, were used to target the inhibitory domain of fH to damaged tissue. The complement receptor 2 (CR2) domain binds to complement fragments deposited on sites of inflammation, and the single chain antibody B4 (B4-scFv) domain binds to modified annexin IV exposed on damaged tissues. Mouse models of neurodegenerative diseases have shown both to be efficacious when administered systemically, locally, and via gene therapy (CR2-fH). Our study suggests that vector-driven CR2-fH and injected B4-scFv-fH localize fH to damaged nerve tissues and mitigate wet AMD and ARHL pathology by reducing macrophage activation and lessening the complement-macrophage inflammatory feedback loop
The Role of Central Amygdala Astrocytes in Ethanol Dependence
Get PDFDependence is a hallmark of alcohol use disorder characterized by excessive alcohol intake and negative withdrawal symptoms. The central nucleus of the amygdala (CeA) is a key brain structure necessary for synaptic and behavioral consequences of ethanol dependence. Accumulating evidence suggests that astrocytes regulate synaptic transmission and behavior, however, a lack a basic understanding of the role of astrocytes in ethanol dependence. Therefore, the following experiments examined the effects of chronic intermittent ethanol (CIE) exposure on astrocyte-neuron interactions in the CeA. Astrocytes, the synaptic marker, synaptojanin1 (SJ1), and astrocytic GABA transporter, GAT3, were immunolabeled and analyzed using super-resolution confocal microscopy and Imaris software. Co-registration of SJ1 with the astrocyte surface was quantified as an index of synaptic proximity. Co-registration with GAT3 was quantified to determine astrocytic expression of GAT3. Triple co-registration of astrocyte-SJ1-GAT3 was quantified to determine the proportion of GAT3-containing astrocyte processes proximal to the synapse. CIE-exposed rats exhibited increased synaptic proximity, GAT3 expression, and increased synaptic proximity of GAT3+ astrocyte processes, indicating that, in the CeA, CIE exposure promotes protrusion of GAT3-containing astrocyte processes toward synapses. Increased synaptic proximity and GAT3 expression was also observed 7 days into withdrawal, suggesting CIE induces persistent alterations in structural astrocytic plasticity. Further, voluntary ethanol intake during withdrawal was positively associated with higher synaptic proximity and GAT3 expression in CIE-exposed rats. Complementary to the morphological data, in vitro slice electrophysiology demonstrated that CIE-exposed rats exhibit indices of increased GABA release, increased tonic current, and increased GAT3-mediated current, supporting the theory that chronic ethanol exposure induces GABA spillover in the CeA. The role of astrocytic GAT3 in dependence-escalated ethanol intake and somatic withdrawal was assessed using viral-mediated GAT3 overexpression and knockdown approaches. GAT3 knockdown resulted in a persistent elevation only in post-dependent ethanol intake, an effect primarily observed in females. In contrast, GAT3 overexpression had no effect in any dependent measures assessed. Together, these findings indicate that CIE exposure remodels astrocyte-neuron interactions in the CeA and implicate CeA astrocytes as a key substrate dysregulated by ethanol dependence
