Disruption of the blood-brain barrier (BBB) is hypothesized to play an important role in the disease biology of schizophrenia (SZ). Brain microvascular endothelial cells (BMECs) have paracellular and transcellular proteins, transporters, as well as important extracellular matrix proteins, which collectively contribute to maintaining proper BBB function. While previous studies have provided some insights into the role of the BBB in SZ pathophysiology, there is a significant gap in our understanding of the cellular-molecular underpinnings of its major component, BMECs. Human induced pluripotent stem cells (hiPSCs) provide an exciting new avenue for exploring the role of BMECs in SZ. We hypothesize that BMECs have intrinsic deficits that lead to BBB dysfunction in SZ. In this study, we first aimed to test whether the existing hiPSC-derived BMEC protocols work with our patient-specific hiPSC samples. Secondly, we sought to investigate any potential deficits between BMECs derived from healthy control (HC) and SZ subjects. We successfully adapted the established protocol and confirmed the identity of these hiPSC-derived BMECs with relevant cell markers such as CLDN5, OCLN, TJP1, PECAM1, and SLC2A1. We also evaluate barrier function by measuring trans-endothelial electrical resistance (TEER) and efflux transporters activity of ABCB1 and ABCC1. We observed evidence of poor cellular adhesion and disrupted tight junctions in a subset of SZ hiPSC-derived BMECs, where approximately 70% of them demonstrated extensive BBB disruption (reduced TEER). These findings suggest that there may be cell-autonomous disease-specific deficits in BMECs in SZ that result in BBB dysfunction. / 2022-06-07T00:00:00Z

Cigarette smoke contributes to many diseases. The actions of second and third hand smoke, which have implications for non-smokers and the very young, are just beginning to be appreciated. The overarching hypothesis of this project is that cigarette smoke has different injurious actions on alveolar cells based on chronological age. The purpose here was to learn more about the susceptibility of alveolar cells to cigarette smoke extract (CSE)- induced injury by performing studies on pulmonary alveolar and endothelial cells derived from neonatal, young, and old rats. The aims involved: 1. Developing cell culture models to study age-related effects of cigarette smoke on alveolar type I cells and microvascular endothelial cells from the lung, and 2. Using these models to examine the effects of CSE on markers of oxidative stress, inflammation and aging in alveolar cells harvested from neonatal, young and old rats. Descriptive and experimental studies involved using a variety of cell culture, biochemical and molecular techniques, including gene expression arrays. The most significant findings were that: 1. primary proliferating alveolar type I cells were used to develop novel cell culture model systems, including single culture, co-culture and three-dimensional cultures that were used to study the effects of CSE; 2. Hydrogen peroxide production by endothelial cells was markedly reduced by co-culturing with AT I cells; 3. Gene expression profiling of oxidative stress-specific pathways suggest that genes responsible for both stopping production of H2O2 or mopping-up H2O2 are involved; and 4. Cigarette smoke shortens telomeres of cells from neonates, but unexpectedly preserves telomere length of cells from young and old rats. Data from telomeric pathway-specific gene expression arrays suggest that there are age-related differences in response to gene expression to CSE. The significant conclusions are: 1. Contrary to prior observations, alveolar type I cells demonstrate prolonged proliferative capacity; 2. Alveolar type I cells likely play an important role in ameliorating CSE-induced oxidative stress; and 3. Neonatal alveolar cells may be more susceptible to the deleterious effects of CSE including telomere shortening. These novel model systems and observations provide new ways to study cigarette smoke-associated lung dysfunction.

The incidences of obesity and type 2 diabetes and their complications are increasing globally. The presence of elevated circulating free fatty acids has been associated with the initial dysfunction of pancreatic beta cells and microvascular endothelial cells followed later by their demise. The aim of this thesis was to investigate the mechanisms by which demise occurs, and how it may be prevented. Palmitate, a saturated fatty acid, caused cell death in both INS-1 beta cells and HCMec/D3 microvascular cells, whereas the unsaturated fatty acid oleic acid did not cause cell death, and also protected against palmitate-induced toxicity. Etomoxir, the mitochondrial CPT1 inhibitor did not rescue INS-1 or HCMec/D3 cells from palmitate-induced toxicity suggesting that palmitate-induced toxicity does not occur via entry into the mitochondria. Cells were exposed to 2-bromopalmitate, a non-metabolisable fatty acid used to reduce the pool of cytoplasmic CoA, to determine whether palmitate-induced toxicity might be mediated by its ability to be activated. Pre-incubation with 2-bromopalmitate in INS-1 cells significantly prevented palmitate-induced cell death. These data suggest that the activation of palmitate with CoA might mediate cell death. Cell cycle analysis found that neither oleic acid nor palmitate caused an increase or decrease in cell proliferation in both INS-1 and HCMec/D3 cells. The data suggest that the mechanism of oleic acid-induced cytoprotection might not be via a pro-proliferative mechanism. INS-1 cells were imaged using spontaneous Raman microspectroscopy after 24-hour exposure to esterified and non-esterified fatty acids. Uni- and multi-variate analysis and spectral decomposition were carried out using a methodology optimised and validated which is presented in this thesis. The aim was to quantify changes, if any, in lipid disposition: distribution, intensity (as a measure of concentration) and composition after exogenous exposure to these fatty acids. Exposure to 0.125 mM palmitate showed a significant decrease in the percentage of lipid within the cells and a corresponding increase in the intensity of this lipid. This suggests that palmitate, alone, might be shuttled into lipid droplets. This was not observed when the cells were exposed to oleic acid, whereby an increase in the intensity of lipid was observed even though no significant change was observed in the percentage of lipid within the cells. When palmitate and oleic acid were combined, the composition of the lipid droplets changed such that the levels of palmitate decreased and the levels of oleic acid increased. These data suggest that oleic acid does not shuttle palmitate into lipid droplets. These data do not support the hypothesis that oleic acid protects against palmitate-induced cytotoxicity by shuttling palmitate into lipid droplets. The methyl esters of palmitate and oleic acid were employed to determine whether they would affect lipid disposition. No change in lipid distribution or intensity was observed when the cells were exposed to these fatty acids, validating the requirement for the free carboxyl oxygen for the covalent binding to glycerol for the formation of lipid droplets. These data also suggest that INS-1 cells cannot de-esterify esterified fatty acids.