Date

2021-9-8

Author

Begentaş, Onur Can

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Multiple Sclerosis (MS) is an autoimmune disease characterized by inflammation, demyelination, and axonal damage resulting in neurodegeneration in the central nervous system (CNS). Relapsing-remitting MS (RRMS) is the most common form of the disease known to affect more than 2 million individuals globally, and the prevalence of the disease is increasing worldwide. As a chronic condition without a cure, RRMS manifests in a relapsing-remitting form with sporadic attacks suddenly appearing, causing neurological dysfunction to proceed by a recovery phase where all symptoms suddenly disappear. Although the factors causing or contributing to MS initiation/progression are not well understood, previous literature has implicated many potential risk factors for the etiology of the disease, including Epstein-Barr virus, smoking, and Vitamin D deficiency. Another potential risk factor implicated in RRMS is sex. Epidemiological studies strongly suggest that MS is a sexually biased disease that is more common in females. Moreover, the disease progression and severity appear to be sexually dimorphic since the progression and the symptoms are worse in males; however, more inflammatory in females. Importantly, research suggests that biological sex differences beyond gender-related factors may be crucial in RRMS; however, how biological sex differences affect the disease initiation or progression remain unknown. The hallmark of MS is demyelination, which is the loss of the myelin sheath around axons in the CNS. Oligodendrocytes are the glial cells generating myelin sheath to axons in CNS. It is well established that autoimmune response in MS leads to damage and potentially loss of oligodendrocytes, eventually leading to neurodegeneration. Current therapeutic approaches for MS are only limited to eliminating the symptoms caused by the autoimmune attacks. While such disease-modifying therapies help suppress autoimmune attacks and eventually lower the frequency of attacks, there are no available therapeutics to induce remyelination. Clearly, there is a need for more advanced approaches in MS that would induce remyelination besides immunosuppression. To develop effective therapeutic options that can induce remyelination to complement existing immunosuppressive drugs, a better understanding of cellular processes in remyelination is needed. To facilitate such studies, reliable model systems are necessary for mechanism and drug discovery studies. Human induced pluripotent stem cells (iPSCs) based approaches can provide such systems. Due to their nature and ability to form every possible cell type from the three embryonic germ layers, they can now be easily generated from patients’ somatic cells to generate patient-specific cell types. iPSCs can be utilized to obtain cell types that are normally very hard to obtain on a large scale, especially for CNS disease modeling. Indeed, numerous studies have demonstrated that iPSCs can be successfully differentiated to neuronal and glial cells, and importantly such cells exhibit disease-specific phenotypes in culture. MS iPSCs have also been generated by various groups, and cells differentiated from the iPSCs exhibit disease characteristics, suggesting that these cells can be utilized for MS studies. The main goal in this thesis was to generate and fully characterize iPSC lines from male and female patients and matched controls to facilitate future studies. Towards this goal, blood samples were obtained from age, and sex-matched RRMS patients (3 females and 3 males) and 6 healthy individuals (3 females and 3 males) and Peripheral Blood Mononuclear Cells (PBMCs) were isolated. Following, the PBMCs were reprogrammed using Sendai virus-based reprogramming method, and a total of 12 iPSC lines were established, and their pluripotent characteristics were experimentally characterized. The established iPSC lines will serve as excellent tools for modeling RRMS, enabling us to test multiple approaches to understand the mechanisms governing sex-specific differences and remyelination.

Subject Keywords

Multiple Sclerosis, Disease Modeling, Human Induced Pluripotent Stem Cells, Sendai Virus Based Reprogramming

URI

https://hdl.handle.net/11511/92146

Collections

Graduate School of Natural and Applied Sciences, Thesis