Human Adipose Tissue Lysate-Based Hydrogel for Lasting Immunomodulation to Effectively Improve Spinal Cord Injury Repair.

The long-term inflammatory microenvironment is one of the main obstacles to inhibit acute spinal cord injury (SCI) repair. The natural adipose tissue-derived extracellular matrix hydrogel shows effective anti-inflammatory regulation because of its unique protein components. However, the rapid degradation rate and removal of functional proteins during the decellularization process impair the lasting anti-inflammation function of the adipose tissue-derived hydrogel. To address this problem, adipose tissue lysate provides an effective way for SCI repair due to its abundance of anti-inflammatory and nerve regeneration-related proteins. Thereby, human adipose tissue lysate-based hydrogel (HATLH) with an appropriate degradation rate is developed, which aims to in situ long-term recruit and induce anti-inflammatory M2 macrophages through sustainedly released proteins. HATLH can recruit and polarize M2 macrophages while inhibiting pro-inflammatory M1 macrophages regardless of human or mouse-originated. The axonal growth of neuronal cells also can be effectively improved by HATLH and HATLH-induced M2 macrophages. In vivo experiments reveal that HATLH promotes endogenous M2 macrophages infiltration in large numbers (3.5 × 105/100 µL hydrogel) and maintains a long duration for over a month. In a mouse SCI model, HATLH significantly inhibits local inflammatory response, improves neuron and oligodendrocyte differentiation, enhances axonal growth and remyelination, as well as accelerates neurological function restoration.

Safety and potential efficacy of expanded mesenchymal stromal cells of bone marrow and umbilical cord origins in patients with chronic spinal cord injuries: a phase I/II study.

BACKGROUND AIMS: Spinal cord injury (SCI) affects patients' physical, psychological, and social well-being. Presently, treatment modalities for chronic SCI have restricted clinical effectiveness. Mesenchymal stromal cells (MSCs) demonstrate promise in addressing nervous tissue damage. This single-center, open-label, parallel-group randomized clinical trial aimed to assess the safety and efficacy of intraoperative perilesional administration of expanded autologous bone marrow-derived MSCs (BMMSCs), followed by monthly intrathecal injections, in comparison to monthly intrathecal administration of expanded allogeneic umbilical cord-derived MSCs (UCMSCs) for individuals with chronic SCI. METHODS: Twenty participants, who had a minimum of 1 year of SCI duration, were enrolled. Each participant in Group A received perilesional BMMSCs, followed by monthly intrathecal BMMSCs for three injections, while Group B received monthly intrathecal UCMSCs for three injections. Safety and efficacy were evaluated using the American Spinal Cord Injury Association (ASIA) score for at least 1 year post the final injection. Statistical analysis was conducted using the Wilcoxon signed-rank test. RESULTS: Group A comprised 11 participants, while Group B included 9. The mean follow-up duration was 22.65 months. Mild short-term adverse events encompassed headaches and back pain, with no instances of long-term adverse events. Both groups demonstrated significant improvements in total ASIA scores, with Group A displaying more pronounced motor improvements. CONCLUSIONS: Our findings indicate that perilesional administration of expanded autologous BMMSCs, followed by monthly intrathecal BMMSCs for three injections, or monthly intrathecal UCMSCs for three injections appear to be safe and hold promise for individuals with chronic SCI. Nonetheless, larger-scale clinical trials are imperative to validate these observations.

Repair spinal cord injury with a versatile anti-oxidant and neural regenerative nanoplatform.

Spinal cord injury (SCI) often results in motor and sensory deficits, or even paralysis. Due to the role of the cascade reaction, the effect of excessive reactive oxygen species (ROS) in the early and middle stages of SCI severely damage neurons, and most antioxidants cannot consistently eliminate ROS at non-toxic doses, which leads to a huge compromise in antioxidant treatment of SCI. Selenium nanoparticles (SeNPs) have excellent ROS scavenging bioactivity, but the toxicity control problem limits the therapeutic window. Here, we propose a synergistic therapeutic strategy of SeNPs encapsulated by ZIF-8 (SeNPs@ZIF-8) to obtain synergistic ROS scavenging activity. Three different spatial structures of SeNPs@ZIF-8 were synthesized and coated with ferrostatin-1, a ferroptosis inhibitor (FSZ NPs), to achieve enhanced anti-oxidant and anti-ferroptosis activity without toxicity. FSZ NPs promoted the maintenance of mitochondrial homeostasis, thereby regulating the expression of inflammatory factors and promoting the polarization of macrophages into M2 phenotype. In addition, the FSZ NPs presented strong abilities to promote neuronal maturation and axon growth through activating the WNT4-dependent pathways, while prevented glial scar formation. The current study demonstrates the powerful and versatile bioactive functions of FSZ NPs for SCI treatment and offers inspiration for other neural injury diseases.

Enhancing nerve regeneration in infraorbital nerve injury rat model: effects of vitamin B complex and photobiomodulation.

Orofacial nerve injuries may result in temporary or long-term loss of sensory function and decreased quality of life in patients. B vitamins are required for DNA synthesis and the repair and maintenance of phospholipids. In particular, vitamins B1, B6, and B12 are essential for neuronal function. Deficiency in vitamin B complex (VBC) has been linked to increased oxidative stress, inflammation and demyelination. Photobiomodulation (PBM) has antioxidant activity and is neuroprotective. In addition, a growing literature attests to the positive effects of PBM on nerve repair. To assess the effect of PBM and VBC on regenerative process we evaluated the expression of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), myelin basic protein (MBP), laminin and neurofilaments (NFs) using Western blotting to identify regenerative pattern after chronic constriction injury of the infraorbital nerve (CCI IoN) treated by PBM, VBC or its combination. After CCI IoN, the rats were divided into six groups naive, sham, injured (CCI IoN), treated with photobiomodulation (904 nm, 6.23 J/cm2, CCI IoN + PBM), treated with VBC (containing B1, B6 and B12) 5 times, CCI IoN + VBC) and treated with PBM and VBC (CCI IoN + VBC + PBM). The treatments could revert low expression of BDNF, MBP and laminin. Also reverted the higher expression of neurofilaments and enhanced expression of NGF. PBM and VBC could accelerate injured infraorbital nerve repair in rats through reducing the expression of neurofilaments, increasing the expression of BDNF, laminin and MBP and overexpressing NGF. These data support the notion that the use of PBM and VBC may help in the treatment of nerve injuries. This finding has potential clinical applications.

Role of HDAC5 Epigenetics in Chronic Craniofacial Neuropathic Pain.

The information provided from the papers reviewed here about the role of epigenetics in chronic craniofacial neuropathic pain is critically important because epigenetic dysregulation during the development and maintenance of chronic neuropathic pain is not yet well characterized, particularly for craniofacial pain. We have noted that gene expression changes reported vary depending on the nerve injury model and the reported sample collection time point. At a truly chronic timepoint of 10 weeks in our model of chronic neuropathic pain, functional groupings of genes examined include those potentially contributing to anti-inflammation, nerve repair/regeneration, and nociception. Genes altered after treatment with the epigenetic modulator LMK235 are discussed. All of these differentials are key in working toward the development of diagnosis-targeted therapeutics and likely for the timing of when the treatment is provided. The emphasis on the relevance of time post-injury is reiterated here.

Nanotechnological Research for Regenerative Medicine: The Role of Hyaluronic Acid.

Hyaluronic acid (HA) is a linear, anionic, non-sulfated glycosaminoglycan occurring in almost all body tissues and fluids of vertebrates including humans. It is a main component of the extracellular matrix and, thanks to its high water-holding capacity, plays a major role in tissue hydration and osmotic pressure maintenance, but it is also involved in cell proliferation, differentiation and migration, inflammation, immunomodulation, and angiogenesis. Based on multiple physiological effects on tissue repair and reconstruction processes, HA has found extensive application in regenerative medicine. In recent years, nanotechnological research has been applied to HA in order to improve its regenerative potential, developing nanomedical formulations containing HA as the main component of multifunctional hydrogels systems, or as core component or coating/functionalizing element of nanoconstructs. This review offers an overview of the various uses of HA in regenerative medicine aimed at designing innovative nanostructured devices to be applied in various fields such as orthopedics, dermatology, and neurology.

All-in-one smart dressing for simultaneous angiogenesis and neural regeneration.

Wound repair, along with skin appendage regeneration, is challenged by insufficient angiogenesis and neural regeneration. Therefore, promoting both proangiogenic and neuro-regenerative therapeutic effects is essential for effective wound repair. However, most therapeutic systems apply these strategies separately or ineffectively. This study investigates the performance of an all-in-one smart dressing (ASD) that integrates angiogenic functional materials and multiple biological factors within a light crosslinked hydrogel, forming a multi-functional dressing capable of facilitating simultaneous micro-vascularization and neural regeneration. The ASD uses a zeolite-imidazolate framework 67 with anchored vanadium oxide (VO2@ZIF-67) that allows for the on-demand release of Co2+ with fluctuations in pH at the wound site to stimulate angiogenesis. It can simultaneously release CXCL12, ligustroflavone, and ginsenoside Rg1 in a sustained manner to enhance the recruitment of endogenous mesenchymal stem cells, inhibit senescence, and induce neural differentiation to achieve in situ nerve regeneration. The ASD can stimulate rapid angiogenesis and nerve regeneration within 17 days through multiple angiogenic and neuro-regenerative cues within one dressing. This study provides a proof-of-concept for integrating functional nanomaterials and multiple complementary drugs within a smart dressing for simultaneous angiogenesis and neural regeneration.

Alternating current stimulation promotes neurite outgrowth and plasticity in neurons through activation of the PI3K/AKT signaling pathway.

As a commonly used physical intervention, electrical stimulation (ES) has been demonstrated to be effective in the treatment of central nervous system disorders. Currently, researchers are studying the effects of electrical stimulation on individual neurons and neural networks, which are dependent on factors such as stimulation intensity, duration, location, and neuronal properties. However, the exact mechanism of action of electrical stimulation remains unclear. In some cases, repeated or prolonged electrical stimulation can lead to changes in the morphology or function of the neuron. In this study, immunofluorescence staining and Sholl analysis are used to assess changes in the neurite number and axon length to determine the optimal pattern and stimulation parameters of ES for neurons. Neuronal death and plasticity are detected by TUNEL staining and microelectrode array assays, respectively. mRNA sequencing and bioinformatics analysis are applied to predict the key targets of the action of ES on neurons, and the identified targets are validated by western blot analysis and qRT-PCR. The effects of alternating current stimulation (ACS) on neurons are more significant than those of direct current stimulation (DCS), and the optimal parameters are 3 µA and 20 min. ACS stimulation significantly increases the number of neurites, the length of axons and the spontaneous electrical activity of neurons, significantly elevates the expression of growth-associated protein-43 (GAP-43) without significant changes in the expression of neurotrophic factors. Furthermore, application of PI3K/AKT-specific inhibitors significantly abolishes the beneficial effects of ACS on neurons, confirming that the PI3K/AKT pathway is an important potential signaling pathway in the action of ACS.

Multi-Target Neural Differentiation (MTND) Therapeutic Cocktail to Suppress Brain Tumor.

Brain tumors have been proved challenging to treat. Here we established a Multi-Target Neural Differentiation (MTND) therapeutic cocktail to achieve effective and safe treatment of brain malignancies by targeting the important hallmarks in brain cancers: poor cell differentiation and compromised cell cycle. In-vitro and in-vivo experiments confirmed the significant therapeutic effect of our MTND therapy. Significantly improved therapeutic effects over current first-line chemo-drugs have been identified in clinical cells, with great inhibition of the growth and migration of tumor cells. Further in-vivo experiments confirmed that sustained MTND treatment showed a 73% reduction of the tumor area. MTND also induced strong expression of phenotypes associated with cell cycle exit/arrest and rapid neural reprograming from clinical glioma cells to glutamatergic and GABAergic expressing cells, which are two key neuronal types involved in many human brain functions, including learning and memory. Collectively, MTND induced multi-targeted genotypic expression changes to achieve direct neural conversion of glioma cells and controlled the cell cycle/tumorigenesis development, helping control tumor cells' malignant proliferation and making it possible to treat brain malignant tumors effectively and safely. These encouraging results open avenues to developing new therapies for brain malignancies beyond cytotoxic agents, providing more effective medication recommendations with reduced toxicity.

The Promising Role of a Zebrafish Model Employed in Neural Regeneration Following a Spinal Cord Injury.

Spinal cord injury (SCI) is a devastating event that results in a wide range of physical impairments and disabilities. Despite the advances in our understanding of the biological response to injured tissue, no effective treatments are available for SCIs at present. Some studies have addressed this issue by exploring the potential of cell transplantation therapy. However, because of the abnormal microenvironment in injured tissue, the survival rate of transplanted cells is often low, thus limiting the efficacy of such treatments. Many studies have attempted to overcome these obstacles using a variety of cell types and animal models. Recent studies have shown the utility of zebrafish as a model of neural regeneration following SCIs, including the proliferation and migration of various cell types and the involvement of various progenitor cells. In this review, we discuss some of the current challenges in SCI research, including the accurate identification of cell types involved in neural regeneration, the adverse microenvironment created by SCIs, attenuated immune responses that inhibit nerve regeneration, and glial scar formation that prevents axonal regeneration. More in-depth studies are needed to fully understand the neural regeneration mechanisms, proteins, and signaling pathways involved in the complex interactions between the SCI microenvironment and transplanted cells in non-mammals, particularly in the zebrafish model, which could, in turn, lead to new therapeutic approaches to treat SCIs in humans and other mammals.

The Stem Cell Potential of O-2A Lineage Astroglia.

Astrocytes are the most common glial type in the central nervous system. They play pivotal roles in neurophysiological and neuropathological processes. Mounting evidence indicates that astrocytes may act as neural stem cells and contribute to adult neurogenesis. In previous reports, freshly isolated O-2A progenitors were shown to revert to neural stem-like cells (NSLCs) when cultured with a serum-containing glial medium or bone morphogenic proteins for 3 days and with basic fibroblast growth factor consecutively. NSLCs possess self-renewal and multipotential capacities that can give rise to neurons and glial cells, which suggests that they have stem cell-like properties. However, the underlying molecular mechanisms and cell fate commitment when exposed to a neural conditioned medium remain obscure. In this study, we demonstrated that NSLCs grown in the serum-containing neurobasal medium can differentiate into induced neural-like cells (iNLCs). It was noteworthy that astroglia mixed in these cells, particularly in iNLCs, were gradually replaced by neural phenotypes during this glia-neuron conversion. Remarkably, these glial cells can maintain high levels of proliferation and self-renewal ability by activating the NF-κB and MAPK signals. Finally, we found that Notch, STAT3, autophagy, bHLH, and Wnt signals appear to be critical modulators of these intricate events. Altogether, these data demonstrate that O-2A lineage astroglia can function as neural stem cells and display neurogenic plasticity. Dissecting the regulatory pathways involved in these processes is essential to the understanding of glial cell fate and its precise functions. This finding may foster a better understanding of astrocytic heterogeneity and lead to innovative ways to readily apply stem-like astroglia cells as candidate cell sources for neural repair.

Therapeutic induction of energy metabolism reduces neural tissue damage and increases microglia activation in severe spinal cord injury.

Neural tissue has high metabolic requirements. Following spinal cord injury (SCI), the damaged tissue suffers from a severe metabolic impairment, which aggravates axonal degeneration and neuronal loss. Impaired cellular energetic, tricarboxylic acid (TCA) cycle and oxidative phosphorylation metabolism in neuronal cells has been demonstrated to be a major cause of neural tissue death and regeneration failure following SCI. Therefore, rewiring the spinal cord cell metabolism may be an innovative therapeutic strategy for the treatment of SCI. In this study, we evaluated the therapeutic effect of the recovery of oxidative metabolism in a mouse model of severe contusive SCI. Oral administration of TCA cycle intermediates, co-factors, essential amino acids, and branched-chain amino acids was started 3 days post-injury and continued until the end of the experimental procedures. Metabolomic, immunohistological, and biochemical analyses were performed on the injured spinal cord sections. Administration of metabolic precursors enhanced spinal cord oxidative metabolism. In line with this metabolic shift, we observed the activation of the mTORC1 anabolic pathway, the increase in mitochondrial mass, and ROS defense which effectively prevented the injury-induced neural cell apoptosis in treated animals. Consistently, we found more choline acetyltransferase (ChAT)-expressing motor neurons and increased neurofilament-positive corticospinal axons in the spinal cord parenchyma of the treated mice. Interestingly, oral administration of the metabolic precursors increased the number of activated microglia expressing the CD206 marker suggestive of a pro-resolutive, M2-like phenotype. These molecular and histological modifications observed in treated animals ultimately led to a significant, although partial, improvement of the motor functions. Our data demonstrate that rewiring the cellular metabolism can represent an effective strategy to treat SCI.

Identification of genes involved in neuronal cell death and recovery over time in rat axotomy and neurorrhaphy models through RNA sequencing.

Facial nerves are frequently injured during cosmetic or other types of facial surgery. However, information on the genes involved in the damage and recovery of the facial nerves is limited. Here, we aimed to identify the genes affected by facial nerve injury and repair using next-generation sequencing. We established a rat axotomy model and a parallel epineurial neurorrhaphy model, in which gene expression was analyzed from 3 days to 8 weeks after surgery. We discovered that ARRB1, SGK1, and GSK3B genes associated with neuronal cell death were upregulated in the axotomy model. In contrast, MFRP, MDK, and ACE genes involved in neural recovery and regeneration exhibited higher expression in the neurorrhaphy model. In the present study, the analysis of the big data obtained from the next-generation sequencing (RNA-seq) technology reveals that the expression of genes involved in neuronal cell death is induced during nerve damage, and those associated with neural recovery are more abundantly expressed during repair processes. These results are considered to be useful for the establishment of the treatment of related diseases and basic research in various neuroscience fields by utilizing damage and recovery mechanism of facial nerves.

Neuro-protective effects of nano-formulated hesperetin in a traumatic brain injury model of Danio rerio.

Understanding the mechanism behind neuronal regeneration is critical for treating ischemic stroke and traumatic brain injury. The presence of neural stem cells in and around the sub-ventricular zone of human and also in zebrafish is evidenced. In this current study, the neuro-protective potential of nano-formulated hesperetin on injury-induced neurogenesis in zebrafish was assessed. Nanoformulation of hesperetin was prepared by anti-solvent precipitation technique using sodium dodecyl sulfate (SDS) as the stabilizing agent. The synthesized particles were characterized using SEM, DLS, XRD and FT-IR. Anti-oxidant capacity of nano hesperetin (nHST) in in vitro followed by in vivo studies in a traumatic brain injury (TBI) model of adult zebrafish (Danio rerio), catalase activity, histological analysis and gene expression studies for the genes Sox2, Nestin, Fabp7a and HuC were carried out. The synthesized particles were found to be in nanoscale and SDS had successfully integrated with hesperetin. Moreover, nHST had a significantly higher anti-oxidant capacity in vitro. Catalase levels in nHST treated group were significantly restored compared to other groups. Histological studies supported reduced tissue damage on oral administration of nano-hesperetin as compared to other groups. Gene expression studies showed that nano-hesperetin at a concentration of 10 µM when administered orally induced proliferation of neural stem cells without inducing cell death.

The Antioxidant Phytochemical Schisandrin A Promotes Neural Cell Proliferation and Differentiation after Ischemic Brain Injury.

Schisandrin A (SCH) is a natural bioactive phytonutrient that belongs to the lignan derivatives found in Schisandra chinensis fruit. This study aims to investigate the impact of SCH on promoting neural progenitor cell (NPC) regeneration for avoiding stroke ischemic injury. The promoting effect of SCH on NPCs was evaluated by photothrombotic model, immunofluorescence, cell line culture of NPCs, and Western blot assay. The results showed that neuron-specific class III beta-tubulin (Tuj1) was positive with Map2 positive nerve fibers in the ischemic area after using SCH. In addition, Nestin and SOX2 positive NPCs were significantly (p < 0.05) increased in the penumbra and core. Further analysis identified that SCH can regulate the expression level of cell division control protein 42 (Cdc42). In conclusion, our findings suggest that SCH enhanced NPCs proliferation and differentiation possible by Cdc42 to regulated cytoskeletal rearrangement and polarization of cells, which provides new hope for the late recovery of stroke.

3D Printed Neural Regeneration Devices.

Neural regeneration devices interface with the nervous system and can provide flexibility in material choice, implantation without the need for additional surgeries, and the ability to serve as guides augmented with physical, biological (e.g., cellular), and biochemical functionalities. Given the complexity and challenges associated with neural regeneration, a 3D printing approach to the design and manufacturing of neural devices could provide next-generation opportunities for advanced neural regeneration via the production of anatomically accurate geometries, spatial distributions of cellular components, and incorporation of therapeutic biomolecules. A 3D printing-based approach offers compatibility with 3D scanning, computer modeling, choice of input material, and increasing control over hierarchical integration. Therefore, a 3D printed implantable platform could ultimately be used to prepare novel biomimetic scaffolds and model complex tissue architectures for clinical implants in order to treat neurological diseases and injuries. Further, the flexibility and specificity offered by 3D printed in vitro platforms have the potential to be a significant foundational breakthrough with broad research implications in cell signaling and drug screening for personalized healthcare. This progress report examines recent advances in 3D printing strategies for neural regeneration as well as insight into how these approaches can be improved in future studies.

Regeneration of skin appendages and nerves: current status and further challenges.

Tissue-engineered skin (TES), as an analogue of native skin, is promising for wound repair and regeneration. However, a major drawback of TES products is a lack of skin appendages and nerves to enhance skin healing, structural integrity and skin vitality. Skin appendages and nerves are important constituents for fully functional skin. To date, many studies have yielded remarkable results in the field of skin appendages reconstruction and nerve regeneration. However, patients often complain about a loss of skin sensation and even cutaneous chronic pain. Restoration of pain, temperature, and touch perceptions should now be a major challenge to solve in order to improve patients' quality of life. Current strategies to create skin appendages and sensory nerve regeneration are mainly based on different types of seeding cells, scaffold materials, bioactive factors and involved signaling pathways. This article provides a comprehensive overview of different strategies for, and advances in, skin appendages and sensory nerve regeneration, which is an important issue in the field of tissue engineering and regenerative medicine.

Transplantation of activated olfactory ensheathing cells by curcumin strengthens regeneration and recovery of function after spinal cord injury in rats.

BACKGROUND AIMS: The pro-regeneration capabilities of olfactory ensheathing cells (OECs) remain controversial. However, little is known regarding whether the transplantation of activated OECs by curcumin (CCM) elicits neural regeneration and functional recovery after spinal cord injury (SCI) in rats, and the possible molecular mechanisms have never been investigated. METHODS: Primary OECs were treated with 1µM CCM for 1-3 days. Concomitantly, activated OECs were transplanted into the traumatic spinal cord of Sprague Dawley rats. One to 9 weeks after surgery, the assessment of behavior recovery was made using the Basso, Beattie and Bresnahan (BBB) locomotor scale; electrophysiology tests, such as somatosensory evoked potential (SEP) and motor evoked potential (MEP); and the cylinder test. Pathological study, including hematoxylin and eosin staining and immunofluorescence staining for neurofilaments (NFs), was conducted at 5 weeks post-surgery. In addition, activation profiles of OECs by CCM stimulus were assessed and levels of transglutaminase-2 (TG2) and phosphatidylserine receptor (PSR) in OECs stimulated by CCM were further determined. RESULTS: CCM remarkably enhanced OEC proliferation, improved cell viability and strengthened secretion of neurotrophins and anti-inflammatory factors. In addition, the levels of TG2 and PSR in CCM-treated OECs were significantly elevated. More importantly, beyond 1 week post-transplantation of CCM-treated OECs into lesioned spinal cord, BBB score and cylinder test score were significantly higher than that seen in the other three groups and a more postponed latent SEP and MEP period was noted. Furthermore, 5 weeks later, numerous, well-arranged NF-positive nerve fibers, lesions with less cavities and reduced levels of pro-inflammatory cytokines were found in activated OEC implantation groups. In addition, the number of NF-positive fibers was significantly improved and the number and area of both cavities and gliotic scars were remarkably decreased compared with the corresponding controls. CONCLUSIONS: Transplantation of OECs activated by CCM promotes neural regeneration and functional recovery following SCI, the underlying mechanisms of which are intimately associated with the elevated production of neurotrophic factors and anti-inflammatory factors in OECs stimulated by CCM as well as reduced pro-inflammatory cytokines from the post-contusion spinal cord. In addition, OECs activated by CCM were mediated through TG2 and PSR.

Differentiation of dental pulp stem cells into neuron-like cells.

Background and objectives: With regard to their ease of harvest and common developmental origin, dental pulp stem cells (DPSCs) may act as a favorable source of stem cells in generation of nerves. Moreover; cellular migration and differentiation as well as survival, self-renewal, and proliferation of neuroprogenitor species require the presence of the central nervous system (CNS) mitogens including EGF and bFGF. Accordingly, the possibility of the induction of neuronal differentiation of DPSCs by EGF and bFGF was evaluated in the present study.Materials and methods: DPSCs were treated with 20 ng/ml EGF, 20 ng/ml bFGF, and 10 µg/ml heparin. In order to further induce the neuroprogenitor differentiation, DPSC-derived spheres were also incubated in serum-free media for three days. The resulting spheres were then cultured in high-glucose Dulbecco's Modified Eagle Medium (DMEM) with 10% FBS. The morphology of the cells and the expression of the differentiation markers were correspondingly analyzed by quantitative polymerase chain reaction (qPCR), western blotting, and immunofluorescence (IF).Results: The EGF/bFGF-treated DPSCs showed significant increase in the expression of the neuroprogenitor markers of Nestin and SRY (sex determining region Y)-box 2 (SOX2), 72 h after treatment. The up-regulation of Nestin and SOX2 induced by growth factors was confirmed using western blotting and IF. The cultures also yielded some neuron-like cells with a significant rise in Nestin, microtubule-associated protein 2 (MAP2), and Neurogenin 1 (Ngn1) transcript levels; compared with cells maintained in the control media (p < 0.05).Conclusion: DPSCs seemed to potentially differentiate into neuron-like cells under the herein-mentioned treatment conditions.

Polysialic-Acid-Based Micelles Promote Neural Regeneration in Spinal Cord Injury Therapy.

Spinal cord injury (SCI) routinely causes the immediate loss and disruption of neurons followed by complicated secondary injuries, including inflammation, oxidative stress, and dense glial scar formation. Inhibitory factors in the lesion scar and poor intrinsic neural regeneration capacity restrict functional recovery after injury. Minocycline, which has neuroprotective activity, can alleviate secondary injury, but the long-term administration of this drug may cause toxicity. Polysialic acid (PSA) is a large cell-surface carbohydrate that is critical for central nervous system development and is capable of promoting precursor cell migration, axon path finding, and synaptic remodeling; thus, PSA plays a vital role in tissue repair and regeneration. Here, we developed a PSA-based minocycline-loaded nanodrug delivery system (PSM) for the synergistic therapy of spinal cord injury. The prepared PSM exerted marked anti-inflammatory and neuroprotective activities both in vitro and in vivo. The administration of PSM could significantly protect neurons and myelin sheaths from damage, reduce the formation of glial scar, recruit endogenous neural stem cells to the lesion site, and promote the regeneration of neurons and the extension of long axons throughout the glial scar, thereby largely improving the locomotor function of SCI rats and exerting a superior therapeutic effect. The findings might provide a novel strategy for SCI synergistic therapy and the utilization of PSA in other central nervous system diseases.