Being a Neural Stem Cell: A Matter of Character But Defined by the Microenvironment

Molecular Mechanisms and Clinical Application of Multipotent Stem Cells for Spinal Cord Injury

Spinal Cord Injury (SCI) is a common neurological disorder with devastating psychical and psychosocial sequelae. The majority of patients after SCI suffer from permanent disability caused by motor dysfunction, impaired sensation, neuropathic pain, spasticity as well as urinary complications, and a small number of patients experience a complete recovery. Current standard treatment modalities of the SCI aim to prevent secondary injury and provide limited recovery of lost neurological functions. Stem Cell Therapy (SCT) represents an emerging treatment approach using the differentiation, paracrine, and self-renewal capabilities of stem cells to regenerate the injured spinal cord. To date, multipotent stem cells including mesenchymal stem cells (MSCs), neural stem cells (NSCs), and hematopoietic stem cells (HSCs) represent the most investigated types of stem cells for the treatment of SCI in preclinical and clinical studies. The microenvironment of SCI has a significant impact on the survival, proliferation, and differentiation of transplanted stem cells. Therefore, a deep understanding of the pathophysiology of SCI and molecular mechanisms through which stem cells act may help improve the treatment efficacy of SCT and find new therapeutic approaches such as stem-cell-derived exosomes, gene-modified stem cells, scaffolds, and nanomaterials. In this literature review, the pathogenesis of SCI and molecular mechanisms of action of multipotent stem cells including MSCs, NSCs, and HSCs are comprehensively described. Moreover, the clinical efficacy of multipotent stem cells in SCI treatment, an optimal protocol of stem cell administration, and recent therapeutic approaches based on or combined with SCT are also discussed.

Regenerative Engineering: Current Applications and Future Perspectives

Many pathologies, congenital defects, and traumatic injuries are untreatable by conventional pharmacologic or surgical interventions. Regenerative engineering represents an ever-growing interdisciplinary field aimed at creating biological replacements for injured tissues and dysfunctional organs. The need for bioengineered replacement parts is ubiquitous among all surgical disciplines. However, to date, clinical translation has been limited to thin, small, and/or acellular structures. Development of thicker tissues continues to be limited by vascularization and other impediments. Nevertheless, currently available materials, methods, and technologies serve as robust platforms for more complex tissue fabrication in the future. This review article highlights the current methodologies, clinical achievements, tenacious barriers, and future perspectives of regenerative engineering.

High expression of miR-374a-5p inhibits the proliferation and promotes differentiation of Rencell VM cells by targeting Hes1

The proliferation and differentiation of NSCs are regulated by miRNAs. This study investigated the role of miR-374a-5p in the proliferation and differentiation of ReNcell VM cells. ReNcell VM cells were transfected with miR-374a-5p mimic, miR-374a-5p inhibitor and Hes1, respectively. Cell proliferation was detected by clone formation assay. Target gene for miR-374a-5p was predicted by TargetScan and confirmed by dual-luciferase reporter. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to detect the expressions of relative genes. After culturing the cells in differentiation medium, the ReNcell VM cells differentiated into βIII-tubulin (Tuj1)-positive neurons and GFAP-positive astrocytes. The miR-374a-5p expression was increased as the cells continued to differentiate. Hes1, which was predicted to be the target gene for miR-374a-5p, was low-expressed during cell differentiation. The miR-374a-5p mimic decreased cell clones, inhibited the expressions of ki-67 and Nestin, but increased those of Tuj1 and GFAP. However, miR-374a-5p inhibitor produced the opposite effects to miR-374a-5p mimic. Hes1 increased the expressions of ki-67 and Nestin, but decreased those of Tuj1 and GFAP, moreover, Hes1 reversed the role of miR-374a-5p mimic. MiR-374a-5p inhibited the proliferation of Rencell VM cells and promoted the differentiation of NSCs by reducing the Hes1 expression.

Magnesium promotes the viability and induces differentiation of neural stem cells both in vitro and in vivo

OBJECTIVE

Neural stem cells (NSCs) are multipotent stem cells that generating various neural cells, including neurons, astrocytes and oligodendrocytes. This showed that NSCs is an ideal candidate in the application of neural disease treatment. In the current study, we established a simple and efficient method to promote the viability and induce the differentiation of NSCs by stimulating with magnesium.

METHODS

The proliferation and differentiation of NSCs was determined by MTT assay and immunostaining. The behavior alteration was measured by rotorod test and Morris water maze.

RESULTS

Magnesium enhanced proliferation in NSCs. The ratio of Nestin+, Ki67+ and GFAP+ progenitor cells was increased in the presence of magnesium. Besides, magnesium induced the glial differentiation instead of neuronal differentiation in NSCs. By contrast, transplantation of Mg2+-treated NSCs in vivo generated more neurons. In established PD models, transplantation of Mg2+-treated NSCs could improve the symptoms and recover the memory.

CONCLUSION

We established a simple and efficient way to promote the proliferation and induce the differentiation of NSCs. More importantly, this may also facilitate to develop a new method to neural disorder treatment.

Macrophage-derived GPNMB accelerates skin healing

Healing is a vital response important for the re-establishment of the skin integrity following injury. Delayed or aberrant dermal wound healing leads to morbidity in patients. The development of therapies to improve dermal healing would be useful. Currently, the design of efficient treatments is stalled by the lack of detailed knowledge about the cellular and molecular mechanisms involved in wound healing. Recently, using state-of-the-art technologies, it was revealed that macrophages signal via GPNMB to mesenchymal stem cells, accelerating skin healing. Strikingly, transplantation of macrophages expressing GPNMB improves skin healing in GPNMB-mutant mice. Additionally, topical treatment with recombinant GPNMB restored mesenchymal stem cells recruitment and accelerated wound closure in the diabetic skin. From a drug development perspective, this GPNMB is a new candidate for skin healing.