Isolation and differentiation of neural stem/progenitor cells from fetal rat dorsal root ganglia

Benzeneboronic acid-modified hyaluronic acid hydrogel enhances the differentiation of dorsal root ganglion stem cells in a three-dimensional environment

Peripheral nerve injuries (PNI) remain challenging to treat due to limited regeneration capacity and the lack of effective therapeutic scaffolds to support nerve repair. This study aims to develop and evaluate a 3-aminophenylboronic acid-modified hyaluronic acid (HAB) hydrogel as a 3D scaffold to enhance Dorsal root ganglion-derived stem cells (DRGSCs) attachment, migration, and neuronal differentiation for peripheral nerve regeneration. The HAB hydrogel was synthesized through an amidation reaction and characterized using Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H NMR). DRGSCs were cultured in HAB hydrogel, and neuronal differentiation was assessed through immunofluorescence staining, PCR, and multi-electrode array (MEA) recordings. Cytotoxicity, proliferation, and in vivo biocompatibility were evaluated through live/dead staining, CCK-8 assays, and subcutaneous implantation in rats. Transcriptomic analysis was performed to explore gene expression profiles. Our results shown that DRGSCs cultured in HAB hydrogel exhibited significantly improved attachment (78.5 % ± 3.2 % vs. 45.3 % ± 2.8 %, p < 0.05) and migration speeds (21.4 μm/h vs. 12.9 μm/h, p < 0.05) compared to 2D cultures. Neuronal differentiation efficiency, as indicated by Tuj1-positive cells, was also higher (72.6 % ± 4.1 % vs. 42.8 % ± 3.9 %, p < 0.01). RNA sequencing identified 990 differentially expressed genes (627 upregulated, 363 downregulated), with pathways involved in synaptic vesicle cycling, glutamatergic and GABAergic synapses significantly enriched (p < 0.05). Validation revealed that the expression trends of Gnao1 and Grm7 in the plastic petri dish and HAB hydrogel groups were consistent with the RNA sequencing results. In vivo, the hydrogel showed excellent biocompatibility, with reduced TNF-α and IL-1β expression over a 28-day degradation cycle (p < 0.01). The HAB hydrogel provides a supportive 3D microenvironment that enhances DRGSCs differentiation and electrophysiological activity, highlighting its potential as a promising scaffold for peripheral nerve regeneration and neuroregenerative medicine.

Pathophysiology of Spinal Cord Injury and Tissue Engineering Approach for Its Neuronal Regeneration: Current Status and Future Prospects

A spinal cord injury (SCI) is a very debilitating condition causing loss of sensory and motor function as well as multiple organ failures. Current therapeutic options like surgery and pharmacotherapy show positive results but are incapable of providing a complete cure for chronic SCI symptoms. Tissue engineering, including neuroprotective or growth factors, stem cells, and biomaterial scaffolds, grabs attention because of their potential for regeneration and ability to bridge the gap in the injured spinal cord (SC). Preclinical studies with tissue engineering showed functional recovery and neurorestorative effects. Few clinical trials show the safety and efficacy of the tissue engineering approach. However, more studies should be carried out for potential treatment modalities. In this review, we summarize the pathophysiology of SCI and its current treatment modalities, including surgical, pharmacological, and tissue engineering approaches following SCI in preclinical and clinical phases.

17β-Estradiol Enhances Schwann Cell Differentiation via the ERβ-ERK1/2 Signaling Pathway and Promotes Remyelination in Injured Sciatic Nerves

Remyelination is critical for nerve regeneration. However, the molecular mechanism involved in remyelination is poorly understood. To explore the roles of 17β-estradiol (E2) for myelination in the peripheral nervous system, we used a co-culture model of rat dorsal root ganglion (DRG) explants and Schwann cells (SCs) and a regeneration model of the crushed sciatic nerves in ovariectomized (OVX) and non-ovariectomized (non-OVX) rats for in vitro and in vivo analysis. E2 promoted myelination by facilitating the differentiation of SCs in vitro, which could be inhibited by the estrogen receptors (ER) antagonist ICI182780, ERβ antagonist PHTPP, or ERK1/2 antagonist PD98059. This suggests that E2 accelerates SC differentiation via the ERβ-ERK1/2 signaling. Furthermore, E2 promotes remyelination in crushed sciatic nerves of both OVX and non-OVX rats. Interestingly, E2 also significantly increased the expression of the lysosome membrane proteins LAMP1 and myelin protein P0 in the regenerating nerves. Moreover, P0 has higher degree of colocalization with LAMP1 in the regenerating nerves. Taking together, our results suggest that E2 enhances Schwann cell differentiation and further myelination via the ERβ-ERK1/2 signaling and that E2 increases the expression of myelin proteins and lysosomes in SCs to promotes remyelination in regenerating sciatic nerves.

Nestin immune labeling in human adult trigeminal ganglia

Nestin labels neuroepithelial stem cells and endothelial cells in newly formed blood vessels. The aim of the study was to investigate the immunolocalization of nestin in human adult trigeminal ganglia. Autopsy samples from eight human adult cadavers were paraffin embedded, and immunostained with anti-nestin antibody. Satellite glial cells (SGCs) and intraganglionic microvessels were positively labeled with nestin, which is usually expressed in endothelial cells of newly formed blood vessels. Nestin-positive SGCs have been previously reported in rat trigeminal ganglia. Our study is the first to identify them in human trigeminal ganglia. Further studies are needed to evaluate if the nestin phenotype of SGCs relates to the functional plasticity of these cells or to glial and/or neuronal remodeling in adults. Intrinsic angiogenesis in the adult trigeminal ganglion should be further checked as to whether it relates to a normal vascular remodeling or if it represents an overlooked determinant of trigeminal neuralgia.

Neural progenitor cells derived from adult bone marrow mesenchymal stem cells promote neuronal regeneration

AIM

It is well known that neural stem/progenitor cells (NS/PC) are an ideal cell type for the treatment of central nervous system (CNS) disease. However, ethical problems have severely hampered fetal NS/PC from being widely used as a source for stem cell therapy. Recently, it has been demonstrated that autologous bone marrow mesenchymal stem cells (BMSC) can transdifferentiate into neural progenitor cells (NPC). The biological function of BMSC derived NPC (MDNPC) in neuronal systems remains unknown. In the present study, we aimed to investigate whether MDNPC can promote in vitro neural regeneration, a process comprising mainly the generation of neurons and neurotransmitters.

MAIN METHODS

We co-cultured BMSC, MDNPC or fetal NS/PC with PC12 cells and studied their roles on proliferation, neurite formation and dopamine release from PC12 cells. Furthermore, we also explored the mechanisms by which MDNPC regulate dopamine secretion from PC12 derived neural cells using Western blot.

KEY FINDINGS

We found that both MDNPC and NS/PC had similar morphologies and there were no significant differences between MDNPC and NS/PC in promoting PC12 cell proliferation, neurite outgrowth, and dopamine release. We also demonstrated that NS/PC induced dopamine secretion was associated with an upregulation of dopamine transporter (DAT) levels.

SIGNIFICANCE

In summary, MDNPC were comparable to NS/PC in promoting neural regeneration, indicating that MDNPC are a promising candidate source of neural stem cells for the treatment of neurological diseases.