Neurotrophic Factors Mediated Activation of Astrocytes Ameliorate Memory Loss by Amyloid Clearance after Transplantation of Lineage Negative Stem Cells

Extracellular vesicles from GABAergic but not glutamatergic neurons protect against neurological dysfunction following cranial irradiation

Cranial irradiation used to control brain malignancies invariably leads to progressive and debilitating declines in cognition. Clinical efforts implementing hippocampal avoidance and NMDAR antagonism, have sought to minimize dose to radiosensitive neurogenic regions while normalizing excitatory/inhibitory (E/I) tone. Results of these trials have yielded only marginal benefits to cognition, prompting current studies to evaluate the potential of systemic extracellular vesicle (EV) therapy to restore neurocognitive functionality in the irradiated brain. Here we tested the hypothesis that EVs derived from inhibitory but not excitatory neuronal cultures would prove beneficial to cognition and associated pathology. Rats subjected to a clinically relevant, fractionated cranial irradiation paradigm were given multiple injections of either GABAergic- or glutamatergic-derived EV and subjected to behavioral testing. Rats treated with GABAergic but not glutamatergic EVs showed significant improvements on hippocampal- and cortical-dependent behavioral tasks. While each treatment enhanced levels of the neurotrophic factors BDNF and GDNF, only GABAergic EVs preserved granule cell neuron dendritic spine density. Additional studies conducted with GABAergic EVs, confirmed significant benefits on amygdala-dependent behavior and modest changes in synaptic plasticity as measured by long-term potentiation. These data point to a potentially more efficacious approach for resolving radiation-induced neurological deficits, possibly through a mechanism able to restore homeostatic E/I balance.

The future of stem cell therapies of Alzheimer's disease

Alzheimer's disease (AD) places a heavy burden on the global economy. There is no effective disease-modifying treatment available at present. Since the advent of induced pluripotent stem cells (iPSCs) reprogrammed from human somatic cells, new approaches using iPSC-derived products provided novel insights into AD pathogenesis and drug candidates for the AD treatment. Multiple recent studies using animal models have increased the possibility of reducing pathology and improving cognitive function by cell replacement therapies. In this review, we summarized the advantages, limitations, and future directions of cell replacement therapy, discussed the safety and ethical concerns of this novel therapeutic approach and the possibility of translation to clinical practice.

Brain-Derived Neurotrophic Factor Potentiates Entorhinal-Dentate but not Hippocampus CA1 Pathway in Adult Male Rats: A Mechanism of Taurine-Modulated BDNF on Learning and Memory

Taurine plays an important role in neural growth and function from early to adult life, particularly in learning and memory via BDNF action. This study tested the hypothesis that BDNF differentially potentiates entorhinal-hippocampal synaptic transmission in vivo in adult rats. In anesthetized male Sprague-Dawley rats, a stainless steel recording electrode with an attached microinjector was placed into CA1 and the dentate gyrus to record fEPSP, and a paired stainless steel electrode was inserted into entorhinal cortex for continuous paired-pulse stimulation of that brain region. In the dentate gyrus, microinjection of BDNF resulted in a gradual increase in the peak slope of the fEPSP. Following the infusion, the peak fEPSP began to rise in about 8 min, reached a maximum of 120 ± 2% (from baseline) by about 20 min, and remained near peak elevation (~115%) for more than 30 min. In contrast, the same dose of BDNF when injected into CA1 had no consistent effect on fEPSP slopes in the CA1. Further, an equimolar cytochrome C (horse heart) infusion had no significant effect on fEPSP slopes in either the dentate gyrus or CA1. The potentiation effect of BDNF in the dentate gyrus is consistent with a significant increase in power spectral density of dentate gyrus field potentials at 70-200 Hz, but not at frequencies below 70 Hz. In addition, the CA1 power spectral density was not affected by BDNF (compared to cytochrome C). These data indicate that in vivo BDNF potentiates entorhinal-hippocampal synaptic transmission in dentate gyrus, but not in CA1.

Transplantation Efficacy of Human Ciliary Epithelium Cells from Fetal Eye and Lin-ve Stem Cells from Umbilical Cord Blood in the Murine Retinal Degeneration Model of Laser Injury

A number of degenerative conditions affecting the neural retina including age-related macular degeneration have no successful treatment, resulting in partial or complete vision loss. There are a number of stem cell replacement strategies for recovery of retinal damage using cells from variable sources. However, literature is still deficit in the comparison of efficacy of types of stem cells. The purpose of the study was to compare the therapeutic efficacy of undifferentiated cells, i.e., lineage negative stem cells (Lin-ve SC) with differentiated neurosphere derived from ciliary epithelium (CE) cells on retinal markers associated with laser-induced retinal injury. Laser-induced photocoagulation was carried out to disrupt Bruch’s membrane and retinal pigmented epithelium in C57BL/6 mouse model. Lineage negative cells were isolated from human umbilical cord blood, whereas neurospheres were derived from CE of post-aborted human eyeballs. The cells were then transplanted into subretinal space to study their effect on injury. Markers of neurotropic factors, retina, apoptosis, and proliferation were analyzed after injury and transplantation. mRNA expression was also analyzed by real-time polymerase chain reaction at 1 week, and 3-month immunohistochemistry was evaluated at 1-week time point. CE cell transplantation showed enhanced differentiation of rods and retinal glial cells. However, Lin-ve cells exerted paracrine-dependent modulation of neurotrophic factors, which is possibly mediated by antiapoptotic and proliferative effects. In conclusion, CE transplantation showed superior regenerative outcome in comparison to Lin-ve SC for rescue of artificially injured rodent retinal cells. It is imperative that this source for transplantation may be extensively studied in various doses and additional retinal degeneration models for prospective clinical applications.

Alternative Targets to Fight Alzheimer's Disease: Focus on Astrocytes

The available treatments for patients affected by Alzheimer’s disease (AD) are not curative. Numerous clinical trials have failed during the past decades. Therefore, scientists need to explore new avenues to tackle this disease. In the present review, we briefly summarize the pathological mechanisms of AD known so far, based on which different therapeutic tools have been designed. Then, we focus on a specific approach that is targeting astrocytes. Indeed, these non-neuronal brain cells respond to any insult, injury, or disease of the brain, including AD. The study of astrocytes is complicated by the fact that they exert a plethora of homeostatic functions, and their disease-induced changes could be context-, time-, and disease specific. However, this complex but fervent area of research has produced a large amount of data targeting different astrocytic functions using pharmacological approaches. Here, we review the most recent literature findings that have been published in the last five years to stimulate new hypotheses and ideas to work on, highlighting the peculiar ability of palmitoylethanolamide to modulate astrocytes according to their morpho-functional state, which ultimately suggests a possible potential disease-modifying therapeutic approach for AD.

Prevalence of Diabetes and Its Determinants in the Young Adults Indian Population-Call for Yoga Intervention

Background

The young Indian population, which constitutes 65% of the country, is fast adapting to a new lifestyle, which was not known earlier. They are at a high risk of the increasing burden of diabetes and associated complications. The new evolving lifestyle is not only affecting people's health but also mounting the monetary burden on a developing country such as India.

Aim

We aimed to collect information regarding the prevalence of risk of diabetes in young adults (<35 years) in the 29 most populous states and union territories (7 zones) of India, using a validated questionnaire.

Methods

A user-friendly questionnaire-based survey using a mobile application was conducted on all adults in the 29 most populous states/union territories of India, after obtaining ethical clearance for the study. Here, we report the estimation of the prevalence of the risk of diabetes and self-reported diabetes on 58,821 young individuals below the age of 35 years. Risk for diabetes was assessed using a standardized instrument, the Indian diabetes risk score (IDRS), that has 4 factors (age, family history of diabetes, waist circumference, and physical activity). Spearman's correlation coefficient was used to check the correlations.

Results

The prevalence of high (IDRS score > 60), moderate (IDRS score 30-50), and low (IDRS < 30) diabetes risk in young adults (<35 years) was 10.2%, 33.1%, and 56.7%, respectively. Those with high-risk scores were highest (14.4%) in the Jammu zone and lowest (4.1%) in the central zone. The prevalence of self-reported diabetes was 1.8% with a small difference between men (1.7%) and women (1.9%), and the highest (8.4%) in those with a parental history of diabetes. The south zone had the highest (2.5%), and the north west zone had the lowest (4.4%) prevalence.

Conclusions

Indian youth are at high risk for diabetes, which calls for an urgent action plan through intensive efforts to promote lifestyle behavior modifications during the pandemics of both communicable and noncommunicable diseases.

Magnetic resonance imaging of human neural stem cells in rodent and primate brain

Stem cell transplantation therapies are currently under investigation for central nervous system disorders. Although preclinical models show benefit, clinical translation is somewhat limited by the absence of reliable noninvasive methods to confirm targeting and monitor transplanted cells in vivo. Here, we assess a novel magnetic resonance imaging (MRI) contrast agent derived from magnetotactic bacteria, magneto‐endosymbionts (MEs), as a translatable methodology for in vivo tracking of stem cells after intracranial transplantation. We show that ME labeling provides robust MRI contrast without impairment of cell viability or other important therapeutic features. Labeled cells were visualized immediately post‐transplantation and over time by serial MRI in nonhuman primate and mouse brain. Postmortem tissue analysis confirmed on‐target grft location, and linear correlations were observed between MRI signal, cell engraftment, and tissue ME levels, suggesting that MEs may be useful for determining graft survival or rejection. Overall, these findings indicate that MEs are an effective tool for in vivo tracking and monitoring of cell transplantation therapies with potential relevance to many cellular therapy applications.

Skin-derived precursor Schwann cells protect SH-SY5Y cells against 6-OHDA-induced neurotoxicity by PI3K/AKT/Bcl-2 pathway

Skin-derived precursors (SKPs) are self-renewing and pluripotent adult stem cell sources that have been successfully obtained and cultured from adult tissues of rodents and humans. Skin-derived precursor Schwann cells (SKP-SCs), derived from SKPs when cultured in a neuro stromal medium supplemented with some appropriate neurotrophic factors, have been reported to play a neuroprotective effect in the peripheral nervous system. This proves our previous studies that SKP-SCs' function to bridge sciatic nerve gap in rats. However, the function of SKP-SCs in Parkinson disease (PD) remains unknown. This study was aimed to investigate the possible neuroprotective effects of SKP-SCs in 6-OHDA-induced Parkinson's disease (PD) model. Our results showed that the treatment with SKP-SCs prevented SH-SY5Y cells from 6-OHDA-induced apoptosis, accompanied by modulation of apoptosis-related proteins (Bcl-2 and Bax) and the decreased expression of active caspase-3. Furthermore, we confirmed that SKP-SCs might exert protective effects and increase the mitochondrial membrane potential (MMP) through PI3K/AKT/Bcl-2 pathway. Taken together, our results demonstrated that SKP-SCs protect against 6-OHDA-induced cytotoxicity through PI3K/AKT/Bcl-2 pathway in PD model in vitro, which provides a new theoretical basis for the treatment of PD.

Boosting Antioxidant Self-defenses by Grafting Astrocytes Rejuvenates the Aged Microenvironment and Mitigates Nigrostriatal Toxicity in Parkinsonian Brain via an Nrf2-Driven Wnt/β-Catenin Prosurvival Axis

Astrocyte (As) bidirectional dialog with neurons plays a fundamental role in major homeostatic brain functions, particularly providing metabolic support and antioxidant self-defense against reactive oxygen (ROS) and nitrogen species (RNS) via the activation of NF-E2-related factor 2 (Nrf2), a master regulator of oxidative stress. Disruption of As-neuron crosstalk is chiefly involved in neuronal degeneration observed in Parkinson's disease (PD), the most common movement disorder characterized by the selective degeneration of dopaminergic (DAergic) cell bodies of the substantia nigra (SN) pars compacta (SNpc). Ventral midbrain (VM)-As are recognized to exert an important role in DAergic neuroprotection via the expression of a variety of factors, including wingless-related MMTV integration site 1 (Wnt1), a principal player in DAergic neurogenesis. However, whether As, by themselves, might fulfill the role of chief players in DAergic neurorestoration of aged PD mice is presently unresolved. Here, we used primary postnatal mouse VM-As as a graft source for unilateral transplantation above the SN of aged 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mice after the onset of motor symptoms. Spatio-temporal analyses documented that the engrafted cells promoted: (i) a time-dependent nigrostriatal rescue along with increased high-affinity synaptosomal DA uptake and counteraction of motor deficit, as compared to mock-grafted counterparts; and (ii) a restoration of the impaired microenvironment via upregulation of As antioxidant self-defense through the activation of Nrf2/Wnt/β-catenin signaling, suggesting that grafting As has the potential to switch the SN neurorescue-unfriendly environment to a beneficial antioxidant/anti-inflammatory prosurvival milieu. These findings highlight As-derived factors/mechanisms as the crucial key for successful therapeutic outcomes in PD.