Regenerative Neurology and Regenerative Cardiology: Shared Hurdles and Achievements

Neural Correlates and Molecular Mechanisms of Memory and Learning

Memory and learning are essential cognitive processes that enable us to obtain, retain, and recall information [...].

Emerging Translational Research in Neurological and Psychiatric Diseases: From In Vitro to In Vivo Models

Revealing the underlying pathomechanisms of neurological and psychiatric disorders, searching for new biomarkers, and developing novel therapeutics all require translational research [...].

Use of Brain-Derived Stem/Progenitor Cells and Derived Extracellular Vesicles to Repair Damaged Neural Tissues: Lessons Learned from Connective Tissue Repair Regarding Variables Limiting Progress and Approaches to Overcome Limitations

Pluripotent neural stem or progenitor cells (NSC/NPC) have been reported in the brains of adult preclinical models for decades, as have mesenchymal stem/stromal cells (MSC) been reported in a variety of tissues from adults. Based on their in vitro capabilities, these cell types have been used extensively in attempts to repair/regenerate brain and connective tissues, respectively. In addition, MSC have also been used in attempts to repair compromised brain centres. However, success in treating chronic neural degenerative conditions such as Alzheimer's disease, Parkinson's disease, and others with NSC/NPC has been limited, as have the use of MSC in the treatment of chronic osteoarthritis, a condition affecting millions of individuals. However, connective tissues are likely less complex than neural tissues regarding cell organization and regulatory integration, but some insights have been gleaned from the studies regarding connective tissue healing with MSC that may inform studies attempting to initiate repair and regeneration of neural tissues compromised acutely or chronically by trauma or disease. This review will discuss the similarities and differences in the applications of NSC/NPC and MSC, where some lessons have been learned, and potential approaches that could be used going forward to enhance progress in the application of cellular therapy to facilitate repair and regeneration of complex structures in the brain. In particular, variables that may need to be controlled to enhance success are discussed, as are different approaches such as the use of extracellular vesicles from stem/progenitor cells that could be used to stimulate endogenous cells to repair the tissues rather than consider cell replacement as the primary option. Caveats to all these efforts relate to whether cellular repair initiatives will have long-term success if the initiators for neural diseases are not controlled, and whether such cellular initiatives will have long-term success in a subset of patients if the neural diseases are heterogeneous and have multiple etiologies.

Human Oral Mucosa Stem Cells Increase Survival of Neurons Affected by In Vitro Anoxia and Improve Recovery of Mice Affected by Stroke Through Time-limited Secretion of miR-514A-3p

The success rate of regenerative medicine largely depends on the type of stem cells applied in such procedures. Consequently, to achieve the needed level for clinical standardization, we need to investigate the viability of accessible sources with sufficient quantity of cells. Since the oral region partly originates from the neural crest, which naturally develops in niche with decreased levels of oxygen, the main goal of this work was to test if human oral mucosa stem cells (hOMSC) might be used to treat neurons damaged by anoxia. Here we show that hOMSC are more resistant to anoxia than human induced pluripotent stem cells and that they secrete BDNF, GDNF, VEGF and NGF. When hOMSC were added to human neurons damaged by anoxia, they significantly improved their survival. This regenerative capability was at least partly achieved through miR-514A-3p and SHP-2 and it decreased in hOMSC exposed to neural cells for 14 or 28 days. In addition, the beneficial effect of hOMSC were also confirmed in mice affected by stroke. Hence, in this work we have confirmed that hOMSC, in a time-limited manner, improve the survival of anoxia-damaged neurons and significantly contribute to the recovery of experimental animals following stroke.

The Effect of Liquid-Phase Exfoliated Graphene Film on Neurodifferentiation of Stem Cells from Apical Papilla

BACKGROUND

Dental stem cells, which originate from the neural crest, due to their easy accessibility might be good candidates in neuro-regenerative procedures, along with graphene-based nanomaterials shown to promote neurogenesis in vitro. We aimed to explore the potential of liquid-phase exfoliated graphene (LPEG) film to stimulate the neuro-differentiation of stem cells from apical papilla (SCAP).

METHODS

The experimental procedure was structured as follows: (1) fabrication of graphene film; (2) isolation, cultivation and SCAP stemness characterization by flowcytometry, multilineage differentiation (osteo, chondro and adipo) and quantitative PCR (qPCR); (3) SCAP neuro-induction by cultivation on polyethylene terephthalate (PET) coated with graphene film; (4) evaluation of neural differentiation by means of several microscopy techniques (light, confocal, atomic force and scanning electron microscopy), followed by neural marker gene expression analysis using qPCR.

RESULTS

SCAP demonstrated exceptional stemness, as judged by mesenchymal markers' expression (CD73, CD90 and CD105), and by multilineage differentiation capacity (osteo, chondro and adipo-differentiation). Neuro-induction of SCAP grown on PET coated with graphene film resulted in neuron-like cellular phenotype observed under different microscopes. This was corroborated by the high gene expression of all examined key neuronal markers (Ngn2, NF-M, Nestin, MAP2, MASH1).

CONCLUSIONS

The ability of SCAPs to differentiate toward neural lineages was markedly enhanced by graphene film.

N-acylethanolamide metabolizing enzymes are upregulated in human neural progenitor-derived neurons exposed to sub-lethal oxidative stress

N-acyl amides (NAAs) are a class of lipids that consist of an acyl group N-linked to an amino acid, neurotransmitter, taurine or ethanolamide group (N-acylethanolamines or NAEs) and include some endocannabinoids (eCB) such as anandamide. These lipids are synthesized in a wide variety of organisms and in multiple cell types, including neurons. NAEs are involved in numerous cellular and physiological processes and their concentrations are elevated in response to ischemia and physical trauma to play a role in neuroprotection. The neuroprotective properties of eCB NAEs make the protein targets of these compounds attractive targets for clinical intervention for a variety of conditions. The most promising of these targets include cannabinoid receptor type 1 (CB1), cannabinoid receptor type 2 (CB2), fatty acid amide hydrolase (FAAH), N-acylethanolamine acid amidase (NAAA), and N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD). Further characterization of these targets in a more contemporary model system of neurodegeneration and neuroprotection will allow us to fully describe their role and mechanism of action in neuroprotection against oxidative stress leading to better utilization in the clinical setting. Human stem cell-derived or human neural progenitor cell-derived cells, such as ReN cells, have become more utilized for the study of human neuronal development and neurodegenerative diseases. ReN cells can be easily differentiated thereby circumventing the need for using transformed cell lines and primary neurons as cell model systems. In this study, we determined whether ReN cells, a superior cell model system for studying neurodevelopment, differentiation, and neuroprotection, express proteins involved in canonical eCB NAE signaling and whether oxidative stress can induce their expression. We determined that sublethal oxidative stress upregulates the expression of all eCB proteins tested. In addition, we determined that oxidative stress increases the nuclear localization of FAAH, and to a lesser extent, NAAA and NAPE-PLD. This study is a first step toward determining how oxidative stress affects CB1, CB2, FAAH, NAAA, and NAPE-PLD expression and their potential defense against oxidative stress. As such, our data is important for further determining the role of eCB metabolizing proteins and eCB receptors against oxidative stress.