Human pluripotent stem cells

National Institute Of Neurological Disorders And Stroke

Investigators

Linked publications, trials & patents

Abstract

During the last fiscal year, the NIH SCCF has made progress in a number of areas as highlighted below. Characterization of RSet nave-like pluripotent stem cells: One of the essential properties of human pluripotent stem cells (hPSCs) is the ground or nave pluripotent state that is primarily established in mouse embryonic stem cells (mESCs). Thus far, more than five well-established research groups have reported the existence of human nave pluripotency. However, cell growth conditions and standards have not been defined or established. With Dr. Barbara Mallon, a former SCU member, we have characterized several nave-like pluripotent stem cell lines (NLPs) in terms of their growth patterns, signaling requirements, gene expression profiles, and global methylation. Our defined NLP growth conditions (RSet) may have significant benefits for hPSC growth, downstream differentiation, genetic engineering, disease modeling, and drug discovery. Establishment of a meta-analysis platform for stem cell research: In collaboration with Dr. Kory Johnson and Dr. Yang Fann of the NINDS Bioinformatics IT Group, we established an integrated multivariate meta-analysis platform, significantly improving the predictive value of the current meta-analysis. Accordingly, we were able to reveal various similarities between some nave-like hPSCs and their human and mouse in vitro counterparts. Moreover, we also showed numerous fundamental inconsistencies between diverse nave-like states, which are likely attributed to inter-laboratory protocol differences. This meta-analysis platform is suitable for a broad range of biomedical applications, particularly for stem and cancer cell research. Unraveling SARS-CoV-2 infectivity and predicting therapeutic responses: roles of complex stem-cell organoids: The COVID-19 pandemic is a rapidly evolving and life-threatening situation caused by the SARS-CoV-2 coronavirus. In collaboration with Dr. Kyeyoon Park and Dr. Jason Spence (University of Michigan), we highlighted the emerging roles of complex organoids derived from human pluripotent stem cells and adult stem cells in SARS-CoV-2 cell-entry assays, COVID-19 drug, and in antibody and vaccine development. We provided new insights into the utility of these organoid assays in clinical management of COVID-19 patients during the pandemic, thereby facilitating targeted prevention in vulnerable populations and a precision-and-effective therapy for individual COVID-19 patients. Generation of disease models: We have used the CRISPR/cas9 system to generate cell clones with disruptions in Protein deglycase DJ-1, Parkin,TBK1 and TREM2. Protein deglycase DJ-1, also known as Parkinsons disease protein 7, is a protein which in humans is encoded by the PARK7 gene. Defects in this gene are the cause of autosomal recessive early-onset Parkinson disease. Parkin, also known as Parkinson disease protein 2, is a E3 ubiquitin ligase that plays a critical role in ubiquitination. Parkin recognizes proteins on the outer membrane of mitochondria upon cellular insult and mediates the clearance of damaged mitochondria via autophagy and proteasomal mechanisms. Parkin also enhances cell survival by suppressing both mitochondria-dependent and independent apoptosis. Mutations are associated with mitochondrial dysfunction, leading to neuronal death in autosomal recessive juvenile Parkinson disease. TBK1 (TANK-binding kinase 1) is an enzyme with serine/threonine kinase activity, known for its role in innate immunity antiviral response, but it also regulates cell proliferation, apoptosis, autophagy, and anti-tumor immunity. Loss-of-function mutations of TBK1 are known to cause frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), often combined with memory deficits early in the disease course. TREM2 (triggering receptor expressed on myeloid cells-2) is a surface receptor belonging to the immunoglobulin superfamily. TREM2 is involved in several cellular functions such as cell survival, phagocytosis, pro-inflammatory cytokine production, and cytoskeletal rearrangement. Loss of function mutations in the TREM2 gene are associated with Nasu-Hakola disease, a dementia with bone cysts. Rare heterozygous variants of TREMs are associated with increased risk of developing late-onset Alzheimer disease. Sjogren syndrome is a chronic autoimmune disorder that causes insufficient moisture production in certain glands of the body, including the saliva-producing and tear-producing glands. To study the pathophysiology of Sjogrens syndrome it is imperative to develop an in vitro model system which can reconstitute 3D salivary glands. As an initial step toward building models, induced pluripotent stem cells were generated from salivary epithelial cells of Sjogren syndrome patients in collaboration with Dr. Youngmi Ji at NIDCR. Glial differentiation: Glial cells are increasingly recognized to play a critical role in the development and function of the brain. Moreover, glial cell dysfunction has been shown to contribute to various neurological disorders. Therefore, understanding the function of glial cells under normal as well as pathological conditions is important. To develop optimal protocols for glial differentiation and to provide cells for each glial lineage, human pluripotent stem cells (hPSCs) were employed as a source. As the first target, astrocytes were generated from hPSCs. To do this, hPSCs were first differentiated to neural precursor cells (NPCs), and NPCs were differentiated into astrocyte precursors. The astrocyte precursors were then matured to astrocytes. Microglia are cells of mesodermal/mesenchymal origin that migrate into the CNS to become resident macrophages within the unique brain microenvironment. They play crucial role in the healthy brain as regulators of synaptic functions and phagocytosis. In disease, they play a crucial role in neurodegenerative and neuro-inflammatory conditions. To generate microglia from pluripotent stem cells, hiPSCs were first differentiated into the hematopoietic lineage. The hematopoietic progenitors are then further differentiated into microglia lineage.