The protective effects of neural stem cells and neural stem cells-conditioned medium against inflammation-induced prenatal brain injury

The roles of neural stem cells in myelin regeneration and repair therapy after spinal cord injury

Spinal cord injury (SCI) is a complex tissue injury that results in a wide range of physical deficits, including permanent or progressive disabilities of sensory, motor and autonomic functions. To date, limitations in current clinical treatment options can leave SCI patients with lifelong disabilities. There is an urgent need to develop new therapies for reconstructing the damaged spinal cord neuron-glia network and restoring connectivity with the supraspinal pathways. Neural stem cells (NSCs) possess the ability to self-renew and differentiate into neurons and neuroglia, including oligodendrocytes, which are cells responsible for the formation and maintenance of the myelin sheath and the regeneration of demyelinated axons. For these properties, NSCs are considered to be a promising cell source for rebuilding damaged neural circuits and promoting myelin regeneration. Over the past decade, transplantation of NSCs has been extensively tested in a variety of preclinical models of SCI. This review aims to highlight the pathophysiology of SCI and promote the understanding of the role of NSCs in SCI repair therapy and the current advances in pathological mechanism, pre-clinical studies, as well as clinical trials of SCI via NSC transplantation therapeutic strategy. Understanding and mastering these frontier updates will pave the way for establishing novel therapeutic strategies to improve the quality of recovery from SCI.

NSPCs-ES: mechanisms and functional impact on central nervous system diseases

Patients with central neuronal damage may suffer severe consequences, but effective therapies remain unclear. Previous research has established the transplantation of neural stem cells that generate new neurons to replace damaged ones. In a new field of scientific research, the extracellular secretion of NPSCs (NSPCs-ES) has been identified as an alternative to current chemical drugs. Many preclinical studies have shown that NSPCs-ES are effective in models of various central nervous system diseases (CNS) injuries, from maintaining functional structures at the cellular level to providing anti-inflammatory functions at the molecular level, as well as improving memory and motor functions, reducing apoptosis in neurons, and mediating multiple signaling pathways. The NSPC-ES can travel to the damaged tissue and exert a broad range of therapeutic effects by supporting and nourishing damaged neurons. However, gene editing and cell engineering techniques have recently improved therapeutic efficacy by modifying NSPCs-ES. Consequently, future research and application of NSPCs-ES may provide a novel strategy for the treatment of CNS diseases in the future. In this review, we summarize the current progress on these aspects.

Human neural stem cell secretome relieves endoplasmic reticulum stress-induced apoptosis and improves neuronal functions after traumatic brain injury in a rat model

Neural stem cell secretome (NSC-S) plays an important role in neuroprotection and recovery. Studies have shown that endoplasmic reticulum stress (ER stress) is involved in the progression of traumatic brain injury (TBI) and is a crucial cause of secondary damage and neuronal death after brain injury. Whether NSC-S is engaged in ER stress and ER stress-mediated neuronal apoptosis post-TBI has not been investigated. In the study, the Feeney SD male rat model was established. The results showed that NSC-S treatment significantly improved the behavior of rats with TBI. In addition, NSC-S relieved ER stress in TBI rats and was observed by transmission electron microscopy and western blot. The specific mechanism was further elucidated that restoration was achieved by alleviating the PERK-eIF2α pathway and thus protecting neurons from apoptosis. Notably, the discovery of calumenin (CALU) in NSC-S by liquid chromatography-tandem mass spectrometry (LC-MS/MS/MS) may be related to the protective effect of NSC-S on ER stress in neurons. Also, the mechanism by which it functions may be related to ubiquitination. In summary, NSC-S improved prognosis and ER stress in TBI rats and might be a promising treatment for relieving TBI.

Comparative Study of the Protective and Neurotrophic Effects of Neuronal and Glial Progenitor Cells-Derived Conditioned Media in a Model of Glutamate Toxicity In Vitro

Cell therapy represents a promising approach to the treatment of neurological diseases, offering potential benefits not only by cell replacement but also through paracrine secretory activities. However, this approach includes a number of limiting factors, primarily related to safety. The use of conditioned stem cell media can serve as an equivalent to cell therapy while avoiding its disadvantages. The present study was a comparative investigation of the antioxidant, neuroprotective and neurotrophic effects of conditioned media obtained from neuronal and glial progenitor cells (NPC-CM and GPC-CM) on the PC12 cell line in vitro. Neuronal and glial progenitor cells were obtained from iPSCs by directed differentiation using small molecules. GPC-CM reduced apoptosis, ROS levels and increased viability, expressions of the antioxidant response genes HMOX1 and NFE2L2 in a model of glutamate-induced oxidative stress. The neurotrophic effect was evidenced by a change in the morphology of pheochromocytoma cells to a neuron-like phenotype. Moreover, neurite outgrowth, expression of GAP43, TUBB3, MAP2, SYN1 genes and increased levels of the corresponding MAP2 and TUBB3 proteins. Treatment with NPC-CM showed moderate antiapoptotic effects and improved cell viability. This study demonstrated the potential application of CM in the field of regenerative medicine.

Human neural stem cells repress glioma cell progression in a paracrine manner by downregulating the Wnt/β-catenin signalling pathway

Neural stem cells (NSCs) play crucial roles in neurological disorders and tissue injury repair through exerting paracrine effects. However, the effects of NSC-derived factors on glioma progression remain unclear. This study aimed to evaluate the effects of human NSC-conditioned medium (NSC-CM) on the behaviour of glioma cells using an in vitro co-culture system. Cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays revealed that NSC-CM inhibited glioma cell proliferation and growth in a fetal bovine serum (FBS)-independent manner. In addition, our wound-healing assay demonstrated that NSC-CM repressed glioma cell migration, while results from transwell and 3D spheroid invasion assays indicated that NSC-CM also reduced the invasion capacity of glioma cells. Flow cytometry showed that NSC-CM prevented cell cycle progression from the G1 to S phase and promoted apoptosis. Western blotting was used to show that the expression of Wnt/β-catenin pathway-related proteins, including β-catenin, c-Myc, cyclin D1, CD44 and Met, was remarkably decreased in NSC-CM-treated glioma cells. Furthermore, the addition of a Wnt/β-catenin pathway activator, CHIR99021, significantly induced the expression of β-catenin and Met and increased the proliferative and invasive capabilities of control medium-treated glioma cells but not those of NSC-CM-treated glioma cells. The use of enzyme-linked immunosorbent assays (ELISA) revealed the secretion of some antitumour factors in human and rat NSCs, including interferon-α and dickkopf-1. Our data suggest that NSC-CM partially inhibits glioma cell progression by downregulating Wnt/β-catenin signalling. This study may serve as a basis for developing future antiglioma therapies based on NSC derivatives.

Neuronal differentiation and functional maturation of neurons from neural stem cells induced by bFGF-chitosan controlled release system

Available methods for differentiating stem cells into neurons require a large number of cytokines and neurotrophic factors, with complex steps and slow processes, and are inefficient to produce functional neurons and form synaptic contacts, which is expensive and impractical in clinical application. Here, we demonstrated a bioactive material, basic fibroblast growth factor (bFGF)-chitosan controlled release system, for facilitating neuronal differentiation from NSCs and the functional maturation of the induced neurons with high efficiency. We illustrated by immunostaining that the neurons derived from NSCs expressed mature immunomarkers of interneurons and excitatory neurons. And we found by patch-clamp that the induced neurons exhibited diverse electrophysiological properties as well as formed functional synapses. In vivo, we implanted bFGF-chitosan into lesion area in traumatic brain injury (TBI) mice and similarly observed abundance of neuroblasts in SVZ and the presence of newborn functional neurons in injury area, which integrated into synaptic networks. Taken together, our efficient and rapid tissue engineering approach may be a potential method for the generation of functional neuronal lineage cells from stem cells and a therapy of brain injury and disease.

Immunomodulatory and Anti-inflammatory effect of Neural Stem/Progenitor Cells in the Central Nervous System

Neuroinflammation is a critical event that responds to disturbed homeostasis and governs various neurological diseases in the central nervous system (CNS). The excessive inflammatory microenvironment in the CNS can adversely affect endogenous neural stem cells, thereby impeding neural self-repair. Therapies with neural stem/progenitor cells (NSPCs) have shown significant inhibitory effects on inflammation, which is mainly achieved through intercellular contact and paracrine signalings. The intercellular contact between NSPCs and immune cells, the activated CNS- resident microglia, and astrocyte plays a critical role in the therapeutic NSPCs homing and immunomodulatory effects. Moreover, the paracrine effect mainly regulates infiltrating innate and adaptive immune cells, activated microglia, and astrocyte through the secretion of bioactive molecules and extracellular vesicles. However, the molecular mechanism involved in the immunomodulatory effect of NSPCs is not well discussed. This article provides a systematic analysis of the immunomodulatory mechanism of NSPCs, discusses efficient ways to enhance its immunomodulatory ability, and gives suggestions on clinical therapy.