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The development of highly parallel and affordable high-throughput single-cell transcriptomics technologies has revolutionized our understanding of brain complexity. These methods have been used to build cellular maps of the brain, its different regions, and catalog the diversity of cells in each of them during development, aging and even in disease. Now we know that cellular diversity is way beyond what was previously thought. Single-cell transcriptomics analyses have revealed that cell types previously considered homogeneous based on imaging techniques differ depending on several factors including sex, age and location within the brain. The expression profiles of these cells have also been exploited to understand which are the regulatory programs behind cellular diversity and decipher the transcriptional pathways driving them. In this review, we summarize how single-cell transcriptomics have changed our view on the cellular diversity in the human brain, and how it could impact the way we study neurodegenerative diseases. Moreover, we describe the new computational approaches that can be used to study cellular differentiation and gain insight into the functions of individual cell populations under different conditions and their alterations in disease. [ABSTRACT FROM AUTHOR]

Brain injuries, and neurodegenerative diseases can result in significant disability, lowered quality of life, and mortality. Current treatments including autologous nerve grafts are insufficient. This work presents the creation of new biomimetic supramolecular assemblies as a scaffold for potential applications in neural tissue regeneration. It is composed of polyethylene glycol amide core-conjugated with a thiazole-based building block and a peptide sequence (RVYNMGKGKGFCVPRPLVVYR). This peptide sequence is derived from laminin, a basal membrane protein, and a component of the extracellular matrix of neuronal cells. The product formed was allowed to self-assemble and bound to polypyrrole by layer-by-layer assembly to impart conductive properties (Lam-PEG-thiazole-PPy) resulting in the formation of fibrillar assemblies as indicated by electron microscopy studies. Rheological studies demonstrated that incorporation of PPy resulted in higher storage modulus indicative of higher ability to store deformation energy. Culture of rat olfactory-bulb derived neurons with the assemblies demonstrated that the Lam-PEG-thiazole-PPy assemblies promoted cell proliferation and were able to interact favorably with the cells. After 10 days of culture with the assemblies interconnected networks could be visualized. Furthermore, electrical stimulation resulted in a significant increase in axonal outgrowths. Thus, the assemblies presented herein exhibit potential for applications as a novel scaffold for neural tissue engineering. [ABSTRACT FROM AUTHOR]

Electromagnetic fields (EMFs) could induce oxidative stress (OS) in human tissues. Lipid peroxidation (LPO) is the main hallmark of OS that harms neural cell components, primarily lipids in the myelin sheaths and membranes. Vitamin E is a lipophilic antioxidant that protects cells from OS-related damages and inhibits the LPO process. In this study, male rats were assigned into three groups of Control, EMF, and EMF+ Vitamin E. The EMF producer equipment produced an alternate current of 50 Hz, 3 Mili Tesla (mT). At the end of the experiment, half of the substantia nigra in every sample was used for measurement of the malondialdehyde (MDA) level as the end-product of the LPO and activity of superoxide dismutase (SOD) enzyme. The next half of the tissue was prepared for transmission electron microscopy (TEM). In the EMF group, MDA level was enhanced and SOD value decreased significantly compared to the control group, but Vitamin E could restore these changes. In rats undergone EMF, heterochromatic nucleus and destruction in some portions of the nuclear membrane were detected. The segmental separation or destruction of myelin sheath lamellae was observed in nerve fibers. In treated animals, the nucleus was round, less heterochromatic, with a regular membrane. Separation of myelin sheath lamellae in some nerve fibers was slighter than the radiation group. Considering the results, EMF exposure induces LPO and triggers ultrastructural changes in the cell membranes, nucleus, and myelin sheath of substantia nigra cells, but Vitamin E consumption weakens these neuropathological alterations. [ABSTRACT FROM AUTHOR]

Biomaterial implants are a promising strategy to replace neural tissue that is lost after traumatic nerve damage. Chitosan (Ch) is a suitable material for nerve implantation when it is used at a minimum amount of 2% (w/v). The goal of this study was to determine the best mixture of 2% Ch with gelatin (G) and poly(L-lysine) (PLL) for use in neural tissue engineering. Using different physicochemical approaches we showed that all mixtures formed polyelectrolyte complexes with distinct electrostatic interactions between their compounds. This gave rise to different gel morphologies, among which Ch + G exhibited a significantly smaller pore size, unlike Ch + G + PLL. However, thermal resistance to degradation and the wettability of the Ch-based films were not affected. Additionally, these differences affected glial cells growth in long-term (14 days) cultures performed on Ch-based films. Astrocytes and olfactory ensheathing cells proliferated on G and Ch + G films which induced both flattened and spindle cell morphologies. Meanwhile, cortical and hippocampal neurons were similarly viable in all studied films and significantly lower than those observed in controls. Lastly, neurites from dorsal root ganglia extended the most on Ch + G films. These results show that a Ch + G mixture is a promising candidate for use in neural tissue engineering. [ABSTRACT FROM AUTHOR]

Hydrogels, three-dimensional networks of hydrophilic polymers, are currently being investigated for use in a variety of tissue-engineering applications. Hydrogel materials generally exhibit a number of properties including permeability to oxygen and nutrients, which make these materials attractive for use in biological applications. However, in order for such polymers to be successfully integrated into biological systems, these constructs must be engineered so as to mimic native biological interfaces. In this paper we discuss the use of acrylate-based polymers and their derivatives, for use in biomedical applications, including drug delivery, tissue engineering, cell encapsulation, and as templates for directed cell growth, attachment and proliferation. [ABSTRACT FROM AUTHOR]