Role of autophagy in angiogenic potential of vascular pericytes.

The vasculature system is composed of a multiplicity of juxtaposed cells to generate a functional biological barrier between the blood and tissues. On the luminal surface of blood vessels, endothelial cells (ECs) are in close contact with circulating cells while supporting basal lamina and pericytes wrap the abluminal surface. Thus, the reciprocal interaction of pericytes with ECs is a vital element in the physiological activity of the vascular system. Several reports have indicated that the occurrence of pericyte dysfunction under ischemic and degenerative conditions results in varied micro and macro-vascular complications. Emerging evidence points to the fact that autophagy, a conserved self-digestive cell machinery, can regulate the activity of several cells like pericytes in response to various stresses and pathological conditions. Here, we aim to highlight the role of autophagic response in pericyte activity and angiogenesis potential following different pathological conditions.

Human Mesenchymal Stem Cell Transplantation Improved Functional Outcomes Following Spinal Cord Injury Concomitantly with Neuroblast Regeneration.

Purpose: Spinal cord injury (SCI) is damage to the spinal cord that resulted in irreversible neuronal loss, glial scar formation and axonal injury. Herein, we used the human amniotic fluid mesenchymal stem cells (hAF-MSCs) and their conditioned medium (CM), to investigate their ability in neuroblast and astrocyte production as well as functional recovery following SCI. Methods: Fifty-four adult rats were randomly divided into nine groups (n=6), included: Control, SCI, (SCI + DMEM), (SCI + CM), (SCI + MSCs), (SCI + Astrocyte), (SCI + Astrocyte + DMEM), (SCI + Astrocyte + CM) and (SCI + Astrocyte + MSCs). Following laminectomy and SCI induction, DMEM, CM, MSCs, and astrocytes were injected. Western blot was performed to explore the levels of the Sox2 protein in the MSCs-CM. The immunofluorescence staining against doublecortin (DCX) and glial fibrillary acidic protein (GFAP) was done. Finally, Basso-Beattie-Brenham (BBB) locomotor test was conducted to assess the neurological outcomes. Results: Our results showed that the MSCs increased the number of endogenous DCX-positive cells and decreased the number of GFAP-positive cells by mediating juxtacrine and paracrine mechanisms (P<0.001). Transplanted human astrocytes were converted to neuroblasts rather than astrocytes under influence of MSCs and CM in the SCI. Moreover, functional recovery indexes were promoted in those groups that received MSCs and CM. Conclusion: Taken together, our data indicate the MSCs via juxtacrine and paracrine pathways could direct the spinal cord endogenous neural stem cells (NSCs) to the neuroblasts lineage which indicates the capability of the MSCs in the increasing of the number of DCX-positive cells and astrocytes decline.

mTOR signalling pathway in stem cell bioactivities and angiogenesis potential.

The mammalian target of rapamycin (mTOR) is a protein kinase that responds to different stimuli such as stresses, starvation and hypoxic conditions. The modulation of this effector can lead to the alteration of cell dynamic growth, proliferation, basal metabolism and other bioactivities. Considering this fact, the mTOR pathway is believed to regulate the diverse functions in several cell lineages. Due to the pleiotropic effects of the mTOR, we here, hypothesize that this effector can also regulate the bioactivity of stem cells in response to external stimuli pathways under physiological and pathological conditions. As a correlation, we aimed to highlight the close relationship between the mTOR signalling axis and the regenerative potential of stem cells in a different milieu. The relevant publications were included in this study using electronic searches of the PubMed database from inception to February 2023. We noted that the mTOR signalling cascade can affect different stem cell bioactivities, especially angiogenesis under physiological and pathological conditions. Modulation of mTOR signalling pathways is thought of as an effective strategy to modulate the angiogenic properties of stem cells.

Physiological and pathological consequences of exosomes at the blood-brain-barrier interface.

Blood-brain barrier (BBB) interface with multicellular structure controls strictly the entry of varied circulating macromolecules from the blood-facing surface into the brain parenchyma. Under several pathological conditions within the central nervous system, the integrity of the BBB interface is disrupted due to the abnormal crosstalk between the cellular constituents and the recruitment of inflammatory cells. Exosomes (Exos) are nano-sized extracellular vesicles with diverse therapeutic outcomes. These particles transfer a plethora of signaling molecules with the potential to modulate target cell behavior in a paracrine manner. Here, in the current review article, the therapeutic properties of Exos and their potential in the alleviation of compromised BBB structure were discussed. Video Abstract.

Impulsivity and self-regulation: A dual-process model of risky driving in young drivers in Iran.

The dual-process model of risky driving (Lazuras, Rowe, Poulter, Powell, & Ypsilanti, 2019) suggested that regulatory processes mediate the effect of impulsivity on risky driving. The current study aimed to examine the cross-cultural generalisability of this model to Iranian drivers, who are from a country with a markedly higher rate of traffic collisions. We sampled 458 Iranian drivers aged 18 to 25 using an online survey measuring impulsive processes including impulsivity, normlessness and sensation-seeking, and regulatory processes comprising emotion-regulation, trait self-regulation, driving self-regulation, executive functions, reflective functioning and attitudes toward driving. In addition, we used the Driver Behaviour Questionnaire to measure driving violations and errors. Executive functions and driving self-regulation mediated the effect of attention impulsivity on driving errors. Executive functions, reflective functioning, and driving self-regulation mediated the relationship between motor impulsivity and driving errors. Finally, attitudes toward driving safety significantly mediated the relationship of both normlessness and sensation-seeking with driving violations. These results support the mediatory role of cognitive and self-regulatory capacities in the connection between impulsive processes and driving errors and violations. Overall, the present study confirmed the validity of the dual-process model of risky driving in a sample of young drivers in Iran. Implications for educating drivers and implementing policies and interventions based on this model are discussed.

Cellular, histological, and behavioral pathological alterations associated with the mouse model of photothrombotic ischemic stroke.

BACKGROUND: Photothrombotic (PT) stroke model is a reliable method to induce ischemic stroke in the target site using the excitation of photosensitive agents such as Rose Bengal (RB) dye after light illumination. Here, we performed a PT-induced brain ischemic model using a green laser and photosensitive agent RB and confirmed its efficiency through cellular, histological, and neurobehavioral approaches. METHODS: Mice were randomly allocated into RB; Laser irradiation; and RB + Laser irradiation groups. Mice were exposed to a green laser at a wavelength of 532 nm and intensity of 150 mW in a mouse model after injection of RB under stereotactic surgery. The pattern of Hemorrhagic and ischemic changes were evaluated throughout the study. The volume of the lesion site was calculated using unbiased stereological methods. For investigation of neurogenesis, we performed double - (BrdU/NeuN) immunofluorescence (IF) staining on day 28 following the last- BrdU injection. To assess the effect and quality of ischemic stroke on neurological behavior, the Modified neurological severity score (mNSS) test was done on days 1, 7, 14, and 28 days after stroke induction. RESULTS: Laser irradiation plus RB induced hemorrhagic tissue and pale ischemic changes over the 5 days. In the next few days, microscopic staining revealed neural tissue degeneration, demarcated necrotic site, and neuronal injury. BrdU staining showed a significant number of proliferating cells in the periphery of the lesion site in the Laser irradiation plus RB group compared to the group (p < 0.05) while the percent of NeuN+ cells per BrdU- positive cells was reduced. Also, prominent astrogliosis was observed in the periphery of irradiated sites on day 28. Neurological deficits were detected in mice from Laser irradiation plus the RB group. No histological or functional deficits were detected in RB and Laser irradiation groups. CONCLUSIONS: Taken together, our study showed cellular and histologic pathological changes which are associated with the PT induction model. Our findings indicated that the undesirable microenvironment and inflammatory conditions could affect neurogenesis concomitantly with functional deficits. Moreover, this research showed that this model is a focal, reproducible, noninvasive and accessible stroke model with a distinctive demarcation similar to human stroke conditions.

Improvement of spinal cord injury symptoms by targeting the Bax/Bcl2 pathway and modulating TNF-α/IL-10 using Platelet-Rich Plasma exosomes loaded with dexamethasone.

Spinal cord injury (SCI) is a debilitating condition that results in impaired sensory and motor function due to the limited self-regenerative ability of the spinal cord. To address this issue, combination therapy has been proposed as an effective treatment strategy for SCI regeneration. In this study, Platelet-Rich Plasma (PRP)-derived exosomes loaded with dexamethasone were utilized in a mouse model of SCI compression. PRP-derived exosomes loaded with dexamethasone (Dex) were prepared using ultracentrifugation and sonication methods and were administered to the mice via intravenous injection. Following a four-week duration, behavioral assessments were administered to assess functional recuperation, and diverse metrics encompassing the expression of genes associated with apoptosis and antiapoptosis, serum cytokine concentrations and tissue sampling were subjected to thorough examination. The results of this study demonstrated that mice treated with PRP-derived exosomes loaded with Dex (ExoDex) exhibited altered levels of TNF-α and IL-10, along with decreased Bax and increased Bcl2 expression in comparison to the model group. Furthermore, intravenously injected ExoDex reduced the size of the lesion site, lymphocyte infiltration, vacuolation, cavity size and tissue disorganization while also improving locomotor recovery. We propose that the utilization of exosome-loaded Dex therapy holds potential as a promising and clinically relevant approach for injured spinal cord repair. However, further extensive research is warranted in this domain to validate and substantiate the outcomes presented in this study.

Intranasal administration of mitochondria alleviated cognitive impairments and mitochondrial dysfunction in the photothrombotic model of mPFC stroke in mice.

OBJECTIVES: Dysfunction in mitochondrial activity may have profound role in ischemic stroke-induced neuronal death, hence maintaining the mitochondrial function seems to be valuable for neuronal viability and neurological improvement. METHODS: C57BL/6J mice were allocated into sham and stroke groups. Mice in the stroke groups underwent photothrombosis-induced stroke in the medial prefrontal cortex (mPFC) and were divided into the following subgroups; RB, Mito 85, Mito 170, and Mito 340, and received their respective treatments via intra-nasal route every other day (3 days per week) for one week. A battery of behavioral tests including social interaction, passive avoidance, and the Lashley III maze was used to investigate social, contextual, and spatial memories. Moreover, changes in mitochondrial function, including reactive oxygen species (ROS) and ATP levels, and mitochondrial membrane potential, were assessed in mPFC. The expression of growth-associated protein 43 (GAP-43), post-synaptic density-95 (PSD-95), and synaptophysin (SYP) was detected by western blotting. RESULTS: Behavioral results revealed that mitotherapy alleviated ischemia-induced memory impairment. Also, transplantation of exogenous mitochondria lowered ROS, restored ATP generation, and improved mitochondrial membrane potential. Induction of ischemia decreased the levels of synaptic markers in mPFC while exogenous mitochondria (170 and 340µg) significantly upregulated the expression of GAP-43 and PSD-95 after ischemic stroke. CONCLUSION: Our research highlighted the importance of mitotherapy in regulating synaptic markers expression and mitochondria function, which could represent a potential strategy for improving cognitive and memory deficits following stroke.

Neurotrophic factor-secreting cells restored endogenous hippocampal neurogenesis through the Wnt/ß-catenin signaling pathway in AD model mice.

BACKGROUND: Impairment in neurogenesis correlates with memory and  cognitive dysfunction in AD patients. In the recent decade, therapies with stem cell bases are growing and proved to be efficient. This study is a preliminary attempt to explore the impact of NTF-SCs on hippocampal neurogenesis mediated by the Wnt/ß-catenin signaling cascade in AD-like mouse brain parenchyma. METHODS: The BALB/c mice were divided into four groups: Control, AD +Vehicle, AD+ TF-SCs-CM and AD+NTF-SCs (n = 10). For AD induction, 100 µM Aß1-42 was injected into lateral ventricles. The AD-like model was confirmed via passive avoidance test and Thioflavin-S staining 21 days following Aß injection. Next, NTF-SCs were differentiated from ADMSCs, and both NTF-SCs and supernatant (NTF-SCs-CM) were injected into the hippocampus after AD confirmation. Endogenous neural stem cells (NSCs) proliferation capacity was assessed after 50 mg/kbW BrdU injection for 4 days using immunofluorescence (IF) staining. The percent of BrdU/Nestin and BrdU/NeuN positive NSCs were calculated. Real-time RT-PCR was used to detect genes related to the Wnt/ß-catenin signaling cascade. The spatial learning and memory alternation was evaluated using the Morris water maze (MWM). RESULTS: Data showed the reduction in escape latency over 5 days in the AD mice compared to the control group. The administration of NTF-SCs and NTF-SCs-CM increased this value compared to the AD-Vehicle group. Both NTF-SCs and NTF-SCs-CM were the potential to reduce the cumulative distance to the platform in AD mice compared to the AD-Vehicle group. The time spent in target quadrants was ameliorated following NTF-SCs and NTF-SCs-CM transplantation followed by an improved MWM performance. IF imaging revealed the increase in BrdU/Nestin+ and BrdU/NeuN+ in AD mice that received NTF-SCs and NTF-SCs-CM, indicating enhanced neurogenesis. Based on real-time PCR analysis, the expression of PI3K, Akt, MAPK, ERK, Wnt, and ß-catenin was upregulated and coincided with the suppression of GSK-3ß after injection of NTF-SCs-CM and NTF-SCs. In this study, NTF-SCs had superior effects in AD mice that received NTF-SCs compared to NTF-SCs-CM. CONCLUSIONS: The activation of Wnt/ß-catenin pathway via NTF-SCs can be touted as a possible therapeutic approach to restore neurogenesis in AD mice.

Insights into the Critical Role of Exosomes in the Brain; from Neuronal Activity to Therapeutic Effects.

Exo are natural nano-sized vesicles with an endosomal origin that maintain cell-to-cell communications in a paracrine manner. Owing to their physicochemical properties, Exo transfer various types of bioactive metabolites from origin cells to the recipient cells, resulting in induction/inhibition of specific signaling pathways. Like different tissues, Exo are indispensable for the function of neural cells inside the brain parenchyma. Various aspects such as neurogenesis, microglial polarization, and angiogenesis are closely associated with the reciprocal interchanges of Exo between cells in a tightly regulated manner. Similar to physiological conditions, these particles can affect the progression of inflammatory responses following the onset of pathologies. The existence of several uptake exosomal mechanisms, such as receptor-mediated endocytosis, and high penetration capacity into the deep layers of the brain makes Exo promising bio-shuttles for the alleviation of pathological conditions. Like astrocytes, stem cells can release Exo into the surrounding niche with neuroprotective properties regenerative potential. Whether and how Exo can initiate the essential signals required for neurogenesis has not been fully understood. In this review, we will try to elaborate on the putative therapeutic role of Exo in the dynamic activity of neuronal cells.

Neural Stem Cells Secretome Increased Neurogenesis and Behavioral Performance and the Activation of Wnt/ß-Catenin Signaling Pathway in Mouse Model of Alzheimer's Disease.

Alzheimer's disease is a progressive and age-related neurodegenerative disorder that is manifested by neuropathological changes and clinical symptoms. Recently, cell-based therapeutic interventions have been considered as the promising and effective strategies in this field. Herein, we investigated therapeutic effects of neural stem cell secretome on Alzheimer's disease-like model by triggering of Wnt/ß-catenin signaling pathway. In this study, mice were randomly allocated into three different groups as follows: Control, AD + Vehicle, and AD + NSCs-CM groups. To induce mouse model of AD, Aß1-42 was injected into intracerebroventricular region. Following AD-like confirmation through thioflavin S staining and Passive avoidance test, about 5 µl mouse NSCs-CM was injected into the target areas 21 days after AD induction. For evaluation of endogenous proliferation rate (BrdU/Nestin+ cells), 50 µg/kbW BrdU was intraperitoneally injected for 5 consecutive days. To track NSC differentiation, percent of BrdU/NeuN+ cells were monitored via immunofluorescence staining. Histological Nissl staining was done to neurotoxicity and cell death in AD mice after NSCs-CM injection. Morris Water maze test was performed to assess learning and memory performance. Data showed that NSCs-CM could reverse the learning and memory deficits associated with Aß pathology. The reduced expression of Wnt/ß-catenin-related genes such as PI3K, Akt, MAPK, and ERK in AD mice was increased. Along with these changes, NSCs-CM suppressed overactivity of GSK3ß activity induced by Aß deposition. Besides, NSCs increased BrdU/Nestin+ and BrdU/NeuN+ cells in a paracrine manner, indicating proliferation and neural differentiation of NSCs. Moreover, neurotoxicity rate and cell loss were deceased after NSCs-CM injection. In summary, NSCs can regulate adult neurogenesis through modulating of Wnt/ß-catenin signaling pathway and enhance the behavioral performance in the AD mice. These data present the alternative and effective approach in the management of AD and other cognitive impairments.

Effect of aberrant DNA methylation on cancer stem cell properties.

DNA methylation, as an epigenetic mechanism, occurs by adding a methyl group of cytosines in position 5 by DNA methyltransferases and has essential roles in cellular function, especially in the transcriptional regulation of embryonic and adult stem cells. Hypomethylation and hypermethylation cause either the expression or inhibition of genes, and there is a tight balance between regulating the activation or repression of genes in normal cellular activity. Abnormal methylation is well-known hallmark of cancer development and progression and can switch normal stem cells into cancer stem cells. Cancer Stem Cells (CSCs) are minor populations of tumor cells that exhibit unique properties such as self-regeneration, resistance to chemotherapy, and high ability of metastasis. The purpose of this paper is to show how aberrant DNA methylation accumulation affects self-renewal, differentiation, multidrug-resistant, and metastasis processes in cancer stem cells.

Transplantation of bioengineered Reelin-loaded PLGA/PEG micelles can accelerate neural tissue regeneration in photothrombotic stroke model of mouse.

Ischemic stroke is characterized by extensive neuronal loss, glial scar formation, neural tissue degeneration that leading to profound changes in the extracellular matrix, neuronal circuitry, and long-lasting functional disabilities. Although transplanted neural stem cells (NSCs) can recover some of the functional deficit after stroke, retrieval is not complete and repair of lost tissue is negligible. Therefore, the current challenge is to use the combination of NSCs with suitably enriched biomaterials to retain these cells within the infarct cavity and accelerate the formation of a de novo tissue. This study aimed to test the regenerative potential of polylactic-co-glycolic acid-polyethylene glycol (PLGA-PEG) micelle biomaterial enriched with Reelin and embryonic NSCs on photothrombotic stroke model of mice to gain appropriate methods in tissue engineering. For this purpose, two sets of experiments, either in vitro or in vivo models, were performed. In vitro analyses exhibited PLGA-PEG plus Reelin-induced proliferation rate (Ki-67+ NSCs) and neurite outgrowth (axonization and dendritization) compared to PLGA-PEG + NSCs and Reelin + NSCs groups (p < 0.05). Besides, neural differentiation (Map-2+ cells) was high in NSCs cultured in the presence of Reelin-loaded PLGA-PEG micelles (p < 0.05). Double immunofluorescence staining showed that Reelin-loaded PLGA-PEG micelles increased the number of migrating neural progenitor cells (DCX+ cells) and mature neurons (NeuN+ cells) around the lesion site compared to the groups received PLGA-PEG and Reelin alone after 1 month (p < 0.05). Immunohistochemistry results showed that the PLGA/PEG plus Reelin significantly decreased the astrocytic gliosis and increased local angiogenesis (vWF-positive cells) relative to the other groups. These changes led to the reduction of cavity size in the Reelin-loaded PLGA-PEG+NSCs group. Neurobehavioral tests indicated Reelin-loaded PLGA-PEG+NSCs promoted neurological outcome and functional recovery (p < 0.05). These results indicated that Reelin-loaded PLGA-PEG is capable of promoting NSCs dynamic growth, neuronal differentiation, and local angiogenesis following ischemic injury via providing a desirable microenvironment. These features can lead to neural tissue regeneration and functional recovery.

Fabrication, characterization and evaluation of the effect of PLGA and PLGA-PEG biomaterials on the proliferation and neurogenesis potential of human neural SH-SY5Y cells.

In recent years with regard to the development of nanotechnology and neural stem cell discovery, the combinatorial therapeutic strategies of neural progenitor cells and appropriate biomaterials have raised the hope for brain regeneration following neurological disorders. This study aimed to explore the proliferation and neurogenic effect of PLGA and PLGA-PEG nanofibers on human SH-SY5Y cells in in vitro condition. Nanofibers of PLGA and PLGA-PEG biomaterials were synthesized and fabricated using electrospinning method. Physicochemical features were examined using HNMR, FT-IR, and water contact angle assays. Ultrastructural morphology, the orientation of nanofibers, cell distribution and attachment were visualized by SEM imaging. Cell survival and proliferation rate were measured. Differentiation capacity was monitored by immunofluorescence staining of Map-2. HNMR, FT-IR assays confirmed the integration of PEG to PLGA backbone. Water contact angel assay showed increasing surface hydrophilicity in PLGA-PEG biomaterial compared to the PLGA substrate. SEM analysis revealed the reduction of PLGA-PEG nanofibers' diameter compared to the PLGA group. Cell attachment was observed in both groups while PLGA-PEG had a superior effect in the promotion of survival rate compared to other groups (p < .05). Compared to the PLGA group, PLGA-PEG increased the number of Ki67+ cells (p < .01). PLGA-PEG biomaterial induced neural maturation by increasing protein Map-2 compared to the PLGA scaffold in a three-dimensional culture system. According to our data, structural modification of PLGA with PEG could enhance orientated differentiation and the dynamic growth of neural cells.

Biomaterials patterning regulates neural stem cells fate and behavior: The interface of biology and material science.

The combination of nanotechnology and stem cell biology is one of the most promising advances in the field of regenerative medicine. This novel combination has widely been utilized in vitro settings in an attempt to develop efficient therapeutic strategies to overcome the limited capacity of the central nervous system (CNS) in replacing degenerating neural cells with functionally normal cells after the onset of acute and chronic neurological disorders. Importantly, biomaterials, not only, enhance the endogenous CNS neurogenesis and plasticity, but also, could provide a desirable supportive microenvironment to harness the full potential of the in vitro expanded neural stem cells (NSCs) for regenerative purposes. Here, first, we discuss how the physical and biochemical properties of biomaterials, such as their stiffness and elasticity, could influence the behavior of NSCs. Then, since the NSCs niche or microenvironment is of fundamental importance in controlling the dynamic destiny of NSCs such as their quiescent and proliferative states, topographical effects of surface diversity in biomaterials, that is, the micro-and nano-patterned surfaces will be discussed in detail. Finally, the influence of biomaterials as artificial microenvironments on the behavior of NSCs through the specific mechanotransduction signaling pathway mediated by focal adhesion formation will be reviewed.

The Restorative Effect of Human Amniotic Fluid Stem Cells on Spinal Cord Injury.

Spinal cord injury (SCI) is a debilitating condition within the neural system which is clinically manifested by sensory-motor dysfunction, leading, in some cases, to neural paralysis for the rest of the patient's life. In the current study, mesenchymal stem cells (MSCs) were isolated from the human amniotic fluid, in order to study their juxtacrine and paracrine activities. Flow cytometry analysis was performed to identify the MSCs. A conditioned medium (CM) was collected to measure the level of BDNF, IL-1ß, and IL-6 proteins using the ELISA assay. Following the SCI induction, MSCs and CM were injected into the lesion site, and also CM was infused intraperitoneally in the different groups. Two weeks after SCI induction, the spinal cord samples were examined to evaluate the expression of the doublecortin (DCX) and glial fibrillary acid protein (GFAP) markers using immunofluorescence staining. The MSCs' phenotype was confirmed upon the expression and un-expression of the related CD markers. Our results show that MSCs increased the expression level of the DCX and decreased the level of the GFAP relative to the injury group (p < 0.001). Additionally, the CM promoted the DCX expression rate (p < 0.001) and decreased the GFAP expression rate (p < 0.01) as compared with the injury group. Noteworthily, the restorative potential of the MSCs was higher than that of the CM (p < 0.01). Large-scale meta-analysis of transcriptomic data highlighted PAK5, ST8SIA3, and NRXN1 as positively coexpressed genes with DCX. These genes are involved in neuroactive ligand-receptor interaction. Overall, our data revealed that both therapeutic interventions could promote the regeneration and restoration of the damaged neural tissue by increasing the rate of neuroblasts and decreasing the astrocytes.

Current knowledge and challenges associated with targeted delivery of neurotrophic factors into the central nervous system: focus on available approaches.

During the last decades, numerous basic and clinical studies have been conducted to assess the delivery efficiency of therapeutic agents into the brain and spinal cord parenchyma using several administration routes. Among conventional and in-progress administrative routes, the eligibility of stem cells, viral vectors, and biomaterial systems have been shown in the delivery of NTFs. Despite these manifold advances, the close association between the delivery system and regeneration outcome remains unclear. Herein, we aimed to discuss recent progress in the delivery of these factors and the pros and cons related to each modality.

Evaluation of the Effect of Hyaluronic Acid-Based Biomaterial Enriched With Tenascin-C on the Behavior of the Neural Stem Cells.

One of the most important natural extracellular constituents is hyaluronic acid (HA) with the potential to develop a highly organized microenvironment. In the present study, we enriched HA hydrogel with tenascin-C (TN-C) and examined the viability and survival of mouse neural stem cells (NSCs) using different biological assays. Following NSCs isolation and expansion, their phenotype was identified using flow cytometry analysis. Cell survival was measured using MTT assay and DAPI staining after exposure to various concentrations of 50, 100, 200, and 400 nM TN-C. Using acridine orange/ethidium bromide staining, we measured the number of live and necrotic cells after exposure to the combination of HA and TN-C. MTT assay revealed the highest NSCs viability rate in the group exposed to 100 nM TN-C compared to other groups, and a combination of 1% HA + 100 nM TN-C increased the viability of NSCs compared to the HA group after 24 hours. Electron scanning microscopy revealed the higher attachment of these cells to the HA + 100 nM TN-C substrate relative to the HA substrate. Epifluorescence imaging and DAPI staining of loaded cells on HA + 100 nM TN-C substrate significantly increased the number of NSCs per field over 72 hours compared to the HA group (P < 0.05). Live and dead assay revealed that the number of live NSCs significantly increased in the HA + 100 TN-C group compared to HA and control groups. The enrichment of HA substrate with TN-C promoted viability and survival of NSCs and could be applied in neural tissue engineering approaches and regenerative medicine.

Application of neurotrophic factor-secreting cells (astrocyte - Like cells) in the in-vitro Alzheimer's disease-like pathology on the human neuroblastoma cells.

This study investigated physical proximity and paracrine activity of neurotrophic factor-secreting cells (NTF-SCs) on beta-amyloid treated cells. Mesenchymal stem cells (MSCs) - to-NTF-SCs (Astrocyte -like cells) trans-differentiation was confirmed using immunofluorescence staining of GFAP. BDNF and NGF levels were measured by ELISA. To mimic AD-like condition, SH-SY5Y cells were exposed to 10 µM Aß1-42. SH-SY5Y cells were allocated into Control; and Aß1-42-treated cells. Treated cells were further classified into three subgroups including Aß1-42 cells, Aß1-42 cells + NTF-SCs (CM) and Aß1-42 cells + NTF-SCs co-culture. Cell viability was measured by MTT assay. Anti-inflammatory and anti-tau hyperphosphorylation effects of NTF-SCs were assessed via monitoring TNF-α and hyperphosphorylated Tau protein expression level respectively. To explore the impact of NTF-SCs on synaptogenesis and synaptic functionality, real-time PCR assay was performed to measure the expression of synapsine 1, homer 1 and ZIF268. The level of synaptophysin was monitored via immunofluorescence staining. Data showed MSCs potential in trans-differentiating toward NTF-SCs indicated with enhanced GFAP expression (p < 0.05). ELISA assay confirmed the superiority of NTF-SCs in releasing NGF and BDNF compared to the MSCs (p < 0.05). Aß significantly induced SH-SY5Y cells death while juxtacrine and paracrine activity of NTF-SCs significantly blunted these conditions (p < 0.05). Trans-differentiated cells had potential to reduce Tau hyperphosphorylation and TNF-α level after treatment with Aß through juxtacrine and paracrine mechanisms (p < 0.05). Moreover, NTF-SCs significantly increased the expression rate of synapsin 1, homer 1 and zif 268 genes in Aß-treated cells compared to matched-control group coincided with induction of synaptophysin at the protein level(p < 0.05). NTF-SCs reversed AD-like neuropathological alterations in SH-SY5Y cells via paracrine and juxtacrine mechanisms.

Evaluation of the neuroprotective effects of Vitamin E on the rat substantia nigra neural cells exposed to electromagnetic field: An ultrastructural study.

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.