Large-Scale Analysis of Neural Stem Cells and Progenitor Cells

Long-term multilayer adherent network (MAN) expansion, maintenance, and characterization, chemical and genetic manipulation, and transplantation of human fetal forebrain neural stem cells

Human neural stem/precursor cells (hNSC/hNPC) have been targeted for application in a variety of research models and as prospective candidates for cell-based therapeutic modalities in central nervous system (CNS) disorders. To this end, the successful derivation, expansion, and sustained maintenance of undifferentiated hNSC/hNPC in vitro, as artificial expandable neurogenic micro-niches, promises a diversity of applications as well as future potential for a variety of experimental paradigms modeling early human neurogenesis, neuronal migration, and neurogenetic disorders, and could also serve as a platform for small-molecule drug screening in the CNS. Furthermore, hNPC transplants provide an alternative substrate for cellular regeneration and restoration of damaged tissue in neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease. Human somatic neural stem/progenitor cells (NSC/NPC) have been derived from a variety of cadaveric sources and proven engraftable in a cytoarchitecturally appropriate manner into the developing and adult rodent and monkey brain while maintaining both functional and migratory capabilities in pathological models of disease. In the following unit, we describe a new procedure that we have successfully employed to maintain operationally defined human somatic NSC/NPC from developing fetal, pre-term post-natal, and adult cadaveric forebrain. Specifically, we outline the detailed methodology for in vitro expansion, long-term maintenance, manipulation, and transplantation of these multipotent precursors.

Gene expression analysis of RNA purified from embryonic stem cells and embryoid body-derived cells using a high-throughput microarray platform

In this unit, starting with purified RNA, experimental protocols for performing microarray expression analysis of embryonic stem cell lines compared to their corresponding differentiated embryocidal bodies are described. Methods for data analysis are suggested, with the goal of determining which genes are differentially expressed between the preparations. As an example, the use of the Affymetrix microarray expression platform is described, but alternative experimental options for analysis of RNA transcript levels are also summarized. This unit suggests quality control metrics, summarizes the critical parameters necessary for obtaining reproducible experimental results, and outlines quantitative PCR methods for validating microarray results.

Unique glycerophospholipid signature in retinal stem cells correlates with enzymatic functions of diverse long-chain acyl-CoA synthetases

Lipidomics is an emerging research field that comprehensively characterizes lipid molecular species and their metabolic regulation and biological roles. We performed the first lipidomics study on glycerophospholipids (GPLs) in adult mammalian retinal stem cells (RSCs) and non-RSC control cells. A unique GPL signature identified by electrospray ionization tandem mass spectrometry showed new prominent peaks of 16:0 (sn-1)-18:0 (sn-2) or 16:0-16:0 saturated fatty acids, instead of 18:0-20:4 or 18:0-22:6 polyunsaturated essential fatty acids, at 720 m/z of phosphatidylethanolamine, 764 m/z of phosphatidylserine, and 809 m/z of phosphatidylinositol in RSCs (sphere colony RSCs and enriched RSCs), but not in non-RSCs (retinal cells, ciliary cells, sphere colony-derived retinal cells, and nonretinal cells). To seek whether the GPL signature was associated with long-chain acyl-CoA synthetase (LACS), a potential modulator of fatty acid profiles in de novo GPL synthesis, we analyzed gene expression, catabolic activity, substrate selectivity, and inhibitor sensitivity of diverse LACSs. LACSs in RSCs mediated less utilization by GPLs of polyunsaturated essential fatty acids, including arachidonic acid (20:4 [n-6], a second messenger in cell signaling), which was accompanied by lower plasma membrane fluidity in proliferating RSCs compared with differentiated non-RSCs. These novel findings suggest that LACS-associated GPL signature and cell membrane fluidity may participate in regulating proliferation versus differentiation in RSCs and, perhaps, other types of stem cells.

Whole Genome Analysis of Human Neural Stem Cells Derived from Embryonic Stem Cells and Stem and Progenitor Cells Isolated from Fetal Tissue

Multipotent neural stem cells (NSC) have been derived from human embryonic stem cells (hESC) as well as isolated from fetal tissues. However, there have been few exclusive markers of NSC identified to date, and the differences between NSC from various sources are poorly understood. Although cells isolated from these two sources share many important characteristics, it is not clear how closely they are related in terms of gene expression. Here, we compare the gene expression profiles of 11 lines of NSC derived from hESC (ES_NSC), four lines of NSC isolated from fetus (F_NSC), and two lines of restricted progenitors in order to characterize these cell populations and identify differences between NSC derived from these two sources. We showed that ES_NSC were clustered together with high transcriptional similarities but were distinguished from F_NSC, oligodendrocyte precursor cells, and astrocyte precursor cells. There were 17 genes expressed in both ES_NSC and F_NSC whose expression was not identified in restricted neural progenitors. Furthermore, the major differences between ES_NSC and F_NSC were mostly observed in genes related to the key neural differentiation pathways. Here, we show that comparison of global gene expression profiles of ES_NSC, F_NSC, and restricted neural progenitor cells makes it possible to identify some of the common characteristics of NSC and differences between similar stem cell populations derived from hESCs or isolated from fetal tissue. Disclosure of potential conflicts of interest is found at the end of this article.

Heart failure and protein quality control

The heart is constantly under mechanical, metabolic, and thermal stress, even at baseline physiological conditions, and cardiac stress may increase as a result of environmental or intrinsic pathological insults. Cardiomyocytes are continuously challenged to efficiently and properly fold nascent polypeptides, traffic them to their appropriate cellular locations, and keep them from denaturing in the face of normal and pathological stimuli. Because deployment of misfolded or unfolded proteins can be disastrous, cells, in general, and cardiomyocytes, in particular, have developed a multilayered protein quality control system for maintaining proper protein conformation and for reorganizing and removing misfolded or aggregated polypeptides. Here, we examine recent data pointing to the importance of protein quality control in cardiac homeostasis and disease.