Effects of stem cell therapy on protein profile of parkinsonian rats using an(18) O-labeling quantitative proteomic approach

Identification of Proteomic Biomarkers of Acetaminophen-Induced Hepatotoxicity Using Stable Isotope Labeling

Quantitative proteomics approaches based on stable isotopic labeling and mass spectrometry have been widely applied to disease research, drug target discovery, biomarker identification, and systems biology. One of the notable stable isotopic labeling approaches is trypsin-catalyzed 18O/16O labeling, which has its own advantages of low sample consumption, simple labeling procedure, cost-effectiveness, and absence of chemical reactions that potentially generate by-products. In this chapter, a protocol for 18O/16O labeling-based quantitative proteomics approach is described with an application to the identification of proteomic biomarkers of acetaminophen (APAP)-induced hepatotoxicity in rats. The protocol involves first the extraction of proteins from liver tissues of control and APAP-treated rats and digestion into peptides by trypsin. After cleaning of the peptides by solid-phase extraction, equal amounts of peptides from the APAP treatment and the control groups are then subject to trypsin-catalyzed 18O/16O labeling. The labeled peptides are combined and fractionated by off-line strong cation exchange liquid chromatography (SCXLC), and each fraction is then analyzed by nanoflow reversed-phase LC coupled online with tandem mass spectrometry (RPLC-MS/MS) for identification and quantification of differential protein expression between APAP-treated rats and controls. The protocol is applicable to quantitative proteomic analysis for a variety of biological samples.

Hsa_circ_0002468 Regulates the Neuronal Differentiation of SH-SY5Y Cells by Modulating the MiR-561/E2F8 Axis

BACKGROUND It has been shown that circular RNAs (circRNAs) play a vital role in the regulation of neuronal differentiation; however, the precise role of circRNAs in human neuronal differentiation remains largely unexplored. MATERIAL AND METHODS A dual-luciferase reporter assay was carried out to confirm the targets of hsa_circ_0002468, miR-561, E2F8 (E2F transcription factor 8, a protein coding gene), and miR-561. We detected the expression of hsa_circ_0002468, miR-561, and E2F8 by using quantitative real-time polymerase chain reaction (qRT-PCR) analyses. In addition, we performed the functional experiments by using a BrdU (5-bromo-2'-deoxyuridine) assay and qRT-PCR analyses. RESULTS In this study, we showed that hsa_circ_0002468 can act as a sponge of miR-561 to regulate SH-SY5Y proliferation and differentiation. A bioinformatics analysis showed that hsa_circ_0002468 had a binding site that corresponded to miR-561, which was verified by dual-luciferase reporter assay. The expression of hsa_circ_0002468 was increased during SH-SY5Y differentiation and was inversely correlated with miR-561 expression. Using qRT-PCR analysis, we showed that hsa_circ_0002468 negatively regulated miR-561 in SH-SY5Y cells. Intriguingly, the overexpression of hsa_circ_0002468 increased SH-SY5Y differentiation and reduced SH-SY5Y proliferation; the suppression of hsa_circ_0002468 led to decreased SH-SY5Y differentiation levels and increased SH-SY5Y proliferation levels. Additionally, overexpression of miR-561 rescued the SH-SY5Y proliferation deficiency induced by hsa_circ_0002468 overexpression and abolished the SH-SY5Y differentiation promoted by hsa_circ_0002468. Furthermore, E2F8 was validated as a direct target of miR-561. CONCLUSIONS Our data suggested that hsa_circ_0002468 was a novel circRNA that regulated SH-SY5Y cell proliferation and differentiation via targeting the miR-561/E2F8 axis. Therefore, manipulating hsa_circ_0002468 in SH-SY5Y cells could be a novel strategy to develop novel interventions for the treatment of relevant neurological disorders.

Relative and Absolute Quantitation in Mass Spectrometry-Based Proteomics

Mass spectrometry-based quantitative proteomics is a powerful tool for gaining insights into function and dynamics of biological systems. However, peptides with different sequences have different ionization efficiencies, and their intensities in a mass spectrum are not correlated with their abundances. Therefore, various label-free or stable isotope label-based quantitation methods have emerged to assist mass spectrometry to perform comparative proteomic experiments, thus enabling nonbiased identification of thousands of proteins differentially expressed in healthy versus diseased cells. Here, we discuss the most widely used label-free and metabolic-, enzymatic-, and chemical labeling-based proteomic strategies for relative and absolute quantitation. We summarize the specific strengths and weaknesses of each technique in terms of quantification accuracy, proteome coverage, multiplexing capability, and robustness. Applications of each strategy for solving specific biological complexities are also presented.

The Effect of Traditional Chinese Medicine on Neural Stem Cell Proliferation and Differentiation

Neural stem cells (NSCs) are special types of cells with the potential for self-renewal and multi-directional differentiation. NSCs are regulated by multiple pathways and pathway related transcription factors during the process of proliferation and differentiation. Numerous studies have shown that the compound medicinal preparations, single herbs, and herb extracts in traditional Chinese medicine (TCM) have specific roles in regulating the proliferation and differentiation of NSCs. In this study, we investigate the markers of NSCs in various stages of differentiation, the related pathways regulating the proliferation and differentiation, and the corresponding transcription factors in the pathways. We also review the influence of TCM on NSC proliferation and differentiation, to facilitate the development of TCM in neural regeneration and neurodegenerative diseases.

Fasudil Enhances Therapeutic Efficacy of Neural Stem Cells in the Mouse Model of MPTP-Induced Parkinson's Disease

Bone marrow-derived neural stem cells (NSCs) are ideal cells for cellular therapy because of their therapeutic potential for repairing and regenerating damaged neurons. However, the optimization of implanted cells and the improvement of microenvironment in the central nervous system (CNS) are still two critical elements for enhancing therapeutic effect. In the current study, we observed the combined therapeutic effect of NSCs with fasudil in an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) mouse model and explored the possible cellular and molecular mechanisms. The results clearly show that combined treatment of NSCs with fasudil further improves motor capacity of PD mice, thus exerting double effect in treating MPTP-PD. The combined intervention more effectively protected dopaminergic (DA) neurons from loss in the substantia nigra pars compacta (SNpc), which may be associated with the increased number and survival of transplanted NSCs in the brain. Compared with the treatment of fasudil or NSCs alone, the combined intervention more effectively inhibited the activation and aggregation of microglia and astrocytes, displayed stronger anti-inflammatory and antioxidant effects, induced more neurotrophic factor NT-3, and affected the dynamic homeostasis of NMDA and AMPA receptors in MPTP-PD mice. Our study demonstrates that intranasal administration of NSCs, followed by fasudil administration, is a promising cell-based therapy for neuronal lesions.