An injectable hydrogel loaded with GMSCs-derived neural lineage cells promotes recovery after stroke.

Ischemic stroke is a devastating medical condition with poor prognosis due to the lack of effective treatment modalities. Transplantation of human neural stem cells or primary neural cells is a promising treatment approach, but this is hindered by limited suitable cell sources and low in vitro expansion capacity. This study aimed i) to use small molecules to reprogram gingival mesenchymal stem cells (GMSCs) commitment to the neural lineage cells in vitro, and ii) to use hyaluronic acid (HA) hydrogel scaffolds seeded with GMSCs-derived neural lineage cells to treat ischemic stroke invivo. Neural induction was carried out with a small molecule cocktail-based one-step culture protocol over a period of 24 hours. The induced cells were analyzed for expression of neural markers with immunocytochemistry and qRT-PCR. The SD rats (n=100) were subjected to the middle cerebral artery occlusion (MCAO) reperfusion ischemic stroke model. Then, after 8 days post-MCAO, the modelled rats were randomly assigned to six study groups (n=12 per group): (i) GMSCs, (ii) GMSCs-derived neural lineage cells, (iii) HA and GMSCs-derived neural lineage cells, (iv) HA, (v) PBS, and (vi) sham transplantation control, and received their respective transplantation. Evaluation of post-stroke recovery were performed by the behavioral tests and histological assessments. The morphologically altered nature of neural lineages has been observed of the GMSCs treated with small molecules compared to the untreated controls. As shown by the qRT-PCR and immunocytochemistry, small molecules further signifcantly enhanced the experession level of neural markers of GMSCs as compared with the untreated controls (all p<0.05). Intracerebral injection of self-assembling HA hydrogel carrying GMSCs-derived neural lineage cells promoted the recovery of neural function and reduced ischemic damage in rats with ischemic stroke, as demonstrated by histological examination and behavioral assessments (all p<0.05). In conclusion, the small molecule cocktail significantly enhanced the differentiation of GMSCs into neural lineage cells. The HA hydrogel was found to facilitate the proliferation and differentiation of GMSCs-derived neural lineage cells. Furthermore, HA hydrogel seeded with GMSCs-derived neural lineage cells could promote tissue repair and functional recovery in rats with ischemic stroke and may be a promising alternative treatment modality for stroke.

Malaysian brown macroalga Padina australis mitigates lipopolysaccharide-stimulated neuroinflammation in BV2 microglial cells.

Objectives: Neuroinflammation and microglial activation are pathological features in central nervous system disorders. Excess levels of reactive oxygen species (ROS) and pro-inflammatory cytokines have been implicated in exacerbation of neuronal damage during chronic activation of microglial cells. Padina australis, a brown macroalga, has been demonstrated to have various pharmacological properties such as anti-neuroinflammatory activity. However, the underlying mechanism mediating the anti-neuroinflammatory potential of P. australis remains poorly understood. We explored the use of Malaysian P. australis in attenuating lipopolysaccharide (LPS)-stimulated neuroinflammation in BV2 microglial cells. Materials and Methods: Fresh specimens of P. australis were freeze-dried and subjected to ethanol extraction. The ethanol extract (PAEE) was evaluated for its protective effects against 1 µg/ml LPS-stimulated neuroinflammation in BV2 microglial cells. Results: LPS reduced the viability of BV2 microglia cells and increased the levels of nitric oxide (NO), prostaglandin E2 (PGE2), intracellular reactive oxygen species (ROS), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). However, the neuroinflammatory response was reversed by 0.5-2.0 mg/ml PAEE in a dose-dependent manner. Analysis of liquid chromatography-mass spectrometry (LC-MS) of PAEE subfractions revealed five compounds; methyl α-eleostearate, ethyl α-eleostearate, niacinamide, stearamide, and linoleic acid. Conclusion: The protective effects of PAEE against LPS-stimulated neuroinflammation in BV2 microglial cells were found to be mediated by the suppression of excess levels of intracellular ROS and pro-inflammatory mediators and cytokines, denoting the protective role of P. australis in combating continuous neuroinflammation. Our findings support the use of P. australis as a possible therapeutic for neuroinflammatory and neurodegenerative diseases.

Adenosine Improves Mitochondrial Function and Biogenesis in Friedreich's Ataxia Fibroblasts Following L-Buthionine Sulfoximine-Induced Oxidative Stress.

Adenosine is a nucleoside that is widely distributed in the central nervous system and acts as a central excitatory and inhibitory neurotransmitter in the brain. The protective role of adenosine in different pathological conditions and neurodegenerative diseases is mainly mediated by adenosine receptors. However, its potential role in mitigating the deleterious effects of oxidative stress in Friedreich's ataxia (FRDA) remains poorly understood. We aimed to investigate the protective effects of adenosine against mitochondrial dysfunction and impaired mitochondrial biogenesis in L-buthionine sulfoximine (BSO)-induced oxidative stress in dermal fibroblasts derived from an FRDA patient. The FRDA fibroblasts were pre-treated with adenosine for 2 h, followed by 12.50 mM BSO to induce oxidative stress. Cells in medium without any treatments or pre-treated with 5 µM idebenone served as the negative and positive controls, respectively. Cell viability, mitochondrial membrane potential (MMP), aconitase activity, adenosine triphosphate (ATP) level, mitochondrial biogenesis, and associated gene expressions were assessed. We observed disruption of mitochondrial function and biogenesis and alteration in gene expression patterns in BSO-treated FRDA fibroblasts. Pre-treatment with adenosine ranging from 0-600 µM restored MMP, promoted ATP production and mitochondrial biogenesis, and modulated the expression of key metabolic genes, namely nuclear respiratory factor 1 (NRF1), transcription factor A, mitochondrial (TFAM), and NFE2-like bZIP transcription factor 2 (NFE2L2). Our study demonstrated that adenosine targeted mitochondrial defects in FRDA, contributing to improved mitochondrial function and biogenesis, leading to cellular iron homeostasis. Therefore, we suggest a possible therapeutic role for adenosine in FRDA.

Electroactive Biomaterials for Facilitating Bone Defect Repair under Pathological Conditions.

Bone degeneration associated with various diseases is increasing due to rapid aging, sedentary lifestyles, and unhealthy diets. Living bone tissue has bioelectric properties critical to bone remodeling, and bone degeneration under various pathological conditions results in significant changes to these bioelectric properties. There is growing interest in utilizing biomimetic electroactive biomaterials that recapitulate the natural electrophysiological microenvironment of healthy bone tissue to promote bone repair. This review first summarizes the etiology of degenerative bone conditions associated with various diseases such as type II diabetes, osteoporosis, periodontitis, osteoarthritis, rheumatoid arthritis, osteomyelitis, and metastatic osteolysis. Next, the diverse array of natural and synthetic electroactive biomaterials with therapeutic potential are discussed. Putative mechanistic pathways by which electroactive biomaterials can mitigate bone degeneration are critically examined, including the enhancement of osteogenesis and angiogenesis, suppression of inflammation and osteoclastogenesis, as well as their anti-bacterial effects. Finally, the limited research on utilization of electroactive biomaterials in the treatment of bone degeneration associated with the aforementioned diseases are examined. Previous studies have mostly focused on using electroactive biomaterials to treat bone traumatic injuries. It is hoped that this review will encourage more research efforts on the use of electroactive biomaterials for treating degenerative bone conditions.

Antidepressant-like effects of transcorneal electrical stimulation in rat models.

BACKGROUND: Given that visual impairment is bi-directionally associated with depression, we examined whether transcorneal electrical stimulation (TES), a non-invasive treatment for visual disorders, can ameliorate depressive symptoms. OBJECTIVE: The putative antidepressant-like effects of TES and the underlying mechanisms were investigated in an S334ter-line-3 rat model of retinal degeneration and a rat model of chronic unpredictable stress (CUS). METHODS: TES was administered daily for 1 week in S334ter-line-3 and CUS rats. The effects of TES on behavioral parameters, plasma corticosterone levels, and different aspects of neuroplasticity, including neurogenesis, synaptic plasticity, and apoptosis, were examined. RESULTS: In S334ter-line-3 rats, TES induced anxiolytic and antidepressant-like behaviors in the cylinder, open field, home cage emergence, and forced swim tests. In the CUS rat model, TES induced hedonic-like behavior and decreased behavioral despair, which were accompanied by reduced plasma corticosterone levels and upregulated expression of neurogenesis-related genes. Treatment with the neurogenesis blocker temozolomide only inhibited the hedonic-like effect of TES, suggesting the antidepressant-like effects of TES were mediated through both neurogenesis-dependent and -independent mechanisms. Furthermore, TES was found to normalize the protein expression of synaptic markers and apoptotic Bcl-2-associated X protein in the hippocampus and amygdala in the CUS rat model. The improvements in neuroplasticity may involve protein kinase B (AKT) and protein kinase A (PKA) signaling pathways in the hippocampus and amygdala, respectively, as demonstrated by the altered pAKT/AKT and pPKA/PKA ratios. CONCLUSION: The overall findings suggest a possible neuroplasticity mechanism of the antidepressant-like effects of TES.

Mesenchymal stem cell treatment improves outcome of COVID-19 patients via multiple immunomodulatory mechanisms.

The infusion of coronavirus disease 2019 (COVID-19) patients with mesenchymal stem cells (MSCs) potentially improves clinical symptoms, but the underlying mechanism remains unclear. We conducted a randomized, single-blind, placebo-controlled (29 patients/group) phase II clinical trial to validate previous findings and explore the potential mechanisms. Patients treated with umbilical cord-derived MSCs exhibited a shorter hospital stay (P = 0.0198) and less time required for symptoms remission (P = 0.0194) than those who received placebo. Based on chest images, both severe and critical patients treated with MSCs showed improvement by day 7 (P = 0.0099) and day 21 (P = 0.0084). MSC-treated patients had fewer adverse events. MSC infusion reduced the levels of C-reactive protein, proinflammatory cytokines, and neutrophil extracellular traps (NETs) and promoted the maintenance of SARS-CoV-2-specific antibodies. To explore how MSCs modulate the immune system, we employed single-cell RNA sequencing analysis on peripheral blood. Our analysis identified a novel subpopulation of VNN2+ hematopoietic stem/progenitor-like (HSPC-like) cells expressing CSF3R and PTPRE that were mobilized following MSC infusion. Genes encoding chemotaxis factors - CX3CR1 and L-selectin - were upregulated in various immune cells. MSC treatment also regulated B cell subsets and increased the expression of costimulatory CD28 in T cells in vivo and in vitro. In addition, an in vivo mouse study confirmed that MSCs suppressed NET release and reduced venous thrombosis by upregulating kindlin-3 signaling. Together, our results underscore the role of MSCs in improving COVID-19 patient outcomes via maintenance of immune homeostasis.

Therapeutic Potential of Human Stem Cell Implantation in Alzheimer's Disease.

Alzheimer's disease (AD) is a progressive debilitating neurodegenerative disease and the most common form of dementia in the older population. At present, there is no definitive effective treatment for AD. Therefore, researchers are now looking at stem cell therapy as a possible treatment for AD, but whether stem cells are safe and effective in humans is still not clear. In this narrative review, we discuss both preclinical studies and clinical trials on the therapeutic potential of human stem cells in AD. Preclinical studies have successfully differentiated stem cells into neurons in vitro, indicating the potential viability of stem cell therapy in neurodegenerative diseases. Preclinical studies have also shown that stem cell therapy is safe and effective in improving cognitive performance in animal models, as demonstrated in the Morris water maze test and novel object recognition test. Although few clinical trials have been completed and many trials are still in phase I and II, the initial results confirm the outcomes of the preclinical studies. However, limitations like rejection, tumorigenicity, and ethical issues are still barriers to the advancement of stem cell therapy. In conclusion, the use of stem cells in the treatment of AD shows promise in terms of effectiveness and safety.

TGF-ß/Smad Signalling in Neurogenesis: Implications for Neuropsychiatric Diseases.

TGF-ß/Smad signalling has been the subject of extensive research due to its role in the cell cycle and carcinogenesis. Modifications to the TGF-ß/Smad signalling pathway have been found to produce disparate effects on neurogenesis. We review the current research on canonical and non-canonical TGF-ß/Smad signalling pathways and their functions in neurogenesis. We also examine the observed role of neurogenesis in neuropsychiatric disorders and the relationship between TGF-ß/Smad signalling and neurogenesis in response to stressors. Overlapping mechanisms of cell proliferation, neurogenesis, and the development of mood disorders in response to stressors suggest that TGF-ß/Smad signalling is an important regulator of stress response and is implicated in the behavioural outcomes of mood disorders.

Neuroprotective effects of Hericium erinaceus (Bull.: Fr.) Pers. against high-dose corticosterone-induced oxidative stress in PC-12 cells.

BACKGROUND: Hericium erinaceus is a culinary and medicinal mushroom in Traditional Chinese Medicines. It has numerous pharmacological effects including immunomodulatory, anti-tumour, anti-microbial, anti-aging and stimulation of nerve growth factor (NGF) synthesis, but little is known about its potential role in negating the detrimental effects of oxidative stress in depression. The present study investigated the neuroprotective effects of H. erinaceus standardised aqueous extract (HESAE) against high-dose corticosterone-induced oxidative stress in rat pheochromocytoma (PC-12) cells, a cellular model mimicking depression. METHODS: PC-12 cells was pre-treated with HESAE for 48 h followed by 400 µM corticosterone for 24 h to induce oxidative stress. Cells in complete medium without any treatment or pre-treated with 3.125 µg/mL desipramine served as the negative and positive controls, respectively. The cell viability, lactate dehydrogenase (LDH) release, endogenous antioxidant enzyme activities, aconitase activity, mitochondrial membrane potentials (MMPs), intracellular reactive oxygen species (ROS) levels and number of apoptotic nuclei were quantified. In addition, HESAE ethanol extract was separated into fractions by chromatographic methods prior to spectroscopic analysis. RESULTS: We observed that PC-12 cells treated with high-dose corticosterone at 400 µM had decreased cell viability, reduced endogenous antioxidant enzyme activities, disrupted mitochondrial function, and increased oxidative stress and apoptosis. However, pre-treatment with HESAE ranging from 0.25 to 1 mg/mL had increased cell viability, decreased LDH release, enhanced endogenous antioxidant enzyme activities, restored MMP, attenuated intracellular ROS and protected from ROS-mediated apoptosis. The neuroprotective effects could be attributed to significant amounts of adenosine and herierin III isolated from HESAE. CONCLUSIONS: HESAE demonstrated neuroprotective effects against high-dose corticosterone-induced oxidative stress in an in vitro model mimicking depression. HESAE could be a potential dietary supplement to treat depression.

Transplantation of ACE2- Mesenchymal Stem Cells Improves the Outcome of Patients with COVID-19 Pneumonia.

A coronavirus (HCoV-19) has caused the novel coronavirus disease (COVID-19) outbreak in Wuhan, China. Preventing and reversing the cytokine storm may be the key to save the patients with severe COVID-19 pneumonia. Mesenchymal stem cells (MSCs) have been shown to possess a comprehensive powerful immunomodulatory function. This study aims to investigate whether MSC transplantation improves the outcome of 7 enrolled patients with COVID-19 pneumonia in Beijing YouAn Hospital, China, from Jan 23, 2020 to Feb 16, 2020. The clinical outcomes, as well as changes of inflammatory and immune function levels and adverse effects of 7 enrolled patients were assessed for 14 days after MSC injection. MSCs could cure or significantly improve the functional outcomes of seven patients without observed adverse effects. The pulmonary function and symptoms of these seven patients were significantly improved in 2 days after MSC transplantation. Among them, two common and one severe patient were recovered and discharged in 10 days after treatment. After treatment, the peripheral lymphocytes were increased, the C-reactive protein decreased, and the overactivated cytokine-secreting immune cells CXCR3+CD4+ T cells, CXCR3+CD8+ T cells, and CXCR3+ NK cells disappeared in 3-6 days. In addition, a group of CD14+CD11c+CD11bmid regulatory DC cell population dramatically increased. Meanwhile, the level of TNF-α was significantly decreased, while IL-10 increased in MSC treatment group compared to the placebo control group. Furthermore, the gene expression profile showed MSCs were ACE2- and TMPRSS2- which indicated MSCs are free from COVID-19 infection. Thus, the intravenous transplantation of MSCs was safe and effective for treatment in patients with COVID-19 pneumonia, especially for the patients in critically severe condition.

TTC9A deficiency induces estradiol-mediated changes in hippocampus and amygdala neuroplasticity-related gene expressions in female mice.

The involvement of tetratricopeptide repeat domain 9A (TTC9A) deficiency in anxiety-like responses and behavioral despair through estradiol action on the serotonergic system has been reported. Emerging evidence suggests that estradiol is a potent modulator of neuroplasticity. As estradiol and neuroplasticity changes are both implicated in mood regulation, and estradiol activity is negatively regulated by TTC9A, we hypothesized that the behavioral changes induced by Ttc9a-/- is also mediated by neuroplasticity-related mechanisms. To understand the effects of TTC9A and estradiol modulation on neuroplasticity functions, we performed a behavioral analysis of tail suspension immobility and neuroplasticity-related gene expression study of brain samples collected in a previous study involving ovariectomized (OVX) Ttc9a-/- mice with estradiol or vehicle treatment. We observed that OVX-Ttc9a-/- mice had significantly reduced the tail suspension immobility compared to OVX-Ttc9a-/- estradiol-treated mice. Interestingly, there was an upregulation in gene expression of tropomyosin receptor kinase B (Trkb) in the ventral hippocampus, as well as brain-derived neurotrophic factor (Bdnf) and postsynaptic density protein-95 (Psd-95) in the amygdala of OVX-Ttc9a-/- mice compared to those treated with estradiol. These findings indicate that estradiol plays an inhibitory role in neuroplasticity in Ttc9a-/- mice. These observations were not found in the wildtype mice, as the presence of TTC9A suppressed the effects of estradiol. Our data suggest the behavioral alterations in Ttc9a-/- mice were mediated by estradiol regulation involving neuroplasticity-related mechanisms in both the hippocampus and amygdala regions.

Therapeutic Potential of Hericium erinaceus for Depressive Disorder.

Depression is a common and severe neuropsychiatric disorder that is one of the leading causes of global disease burden. Although various anti-depressants are currently available, their efficacies are barely adequate and many have side effects. Hericium erinaceus, also known as Lion's mane mushroom, has been shown to have various health benefits, including antioxidative, antidiabetic, anticancer, anti-inflammatory, antimicrobial, antihyperglycemic, and hypolipidemic effects. It has been used to treat cognitive impairment, Parkinson's disease, and Alzheimer's disease. Bioactive compounds extracted from the mycelia and fruiting bodies of H. erinaceus have been found to promote the expression of neurotrophic factors that are associated with cell proliferation such as nerve growth factors. Although antidepressant effects of H. erinaceus have not been validated and compared to the conventional antidepressants, based on the neurotrophic and neurogenic pathophysiology of depression, H. erinaceus may be a potential alternative medicine for the treatment of depression. This article critically reviews the current literature on the potential benefits of H. erinaceus as a treatment for depressive disorder as well as its mechanisms underlying the antidepressant-like activities.

Human Embryonic Stem Cell-Derived Neural Lineages as In Vitro Models for Screening the Neuroprotective Properties of Lignosus rhinocerus (Cooke) Ryvarden.

In the biomedical field, there is growing interest in using human stem cell-derived neurons as in vitro models for pharmacological and toxicological screening of bioactive compounds extracted from natural products. Lignosus rhinocerus (Tiger Milk Mushroom) is used by indigenous communities in Malaysia as a traditional medicine to treat various diseases. The sclerotium of L. rhinocerus has been reported to have medicinal properties, including various bioactivities such as neuritogenic, anti-inflammatory, and anticancer effects. This study aims to investigate the neuroprotective activities of L. rhinocerus sclerotial extracts. Human embryonic stem cell (hESC)-derived neural lineages exposed to the synthetic glucocorticoid, dexamethasone (DEX), were used as the in vitro models. Excess glucocorticoids have been shown to adversely affect fetal brain development and impair differentiation of neural progenitor cells. Screening of different L. rhinocerus sclerotial extracts and DEX on the hESC-derived neural lineages was conducted using cell viability and neurite outgrowth assays. The neuroprotective effects of L. rhinocerus sclerotial extracts against DEX were further evaluated using apoptosis assays and Western blot analysis. Hot aqueous and methanol extracts of L. rhinocerus sclerotium promoted neurite outgrowth of hESC-derived neural stem cells (NSCs) with negligible cytotoxicity. Treatment with DEX decreased viability of NSCs by inducing apoptosis. Coincubation of L. rhinocerus methanol extract with DEX attenuated the DEX-induced apoptosis and reduction in phospho-Akt (pAkt) level in NSCs. These results suggest the involvement of Akt signaling in the neuroprotection of L. rhinocerus methanol extract against DEX-induced apoptosis in NSCs. Methanol extract of L. rhinocerus sclerotium exhibited potential neuroprotective activities against DEX-induced toxicity in hESC-derived NSCs. This study thus validates the use of human stem cell-derived neural lineages as potential in vitro models for screening of natural products with neuroprotective properties.

EphrinB2 signalling modulates the neural differentiation of human dental pulp stem cells.

Dental pulp stem cells (DPSCs) originate from the embryonic neural crest and have neurogenic potential. The present study investigated the roles of the forward and reverse EphrinB2 signalling pathways during DPSC neurogenesis. Treatment of DPSCs with recombinant EphrinB2-Fc protein over 7 days in a neural induction culture resulted in significant downregulation of the following neural markers: ßIII-Tubulin, neural cell adhesion molecule (NCAM), nestin, neurogenin 2 (NGN2), neurofilament medium polypeptide and Musashi1. Immunocytochemistry revealed that EphrinB2-Fc-treated DPSCs exhibited more rounded morphologies with fewer neurite outgrowths as well as reduced protein expression of ßIII-tubulin and NGN2. Treatment of DPSCs with a peptide inhibitor specific to the EphB4 receptor significantly upregulated expression of the neural markers microtubule-associated protein 2, Musashi1, NGN2 and neuron-specific enolase, whereas treatment with a peptide inhibitor specific to the EphB2 receptor exerted negligible effects on neurogenesis. Transgenic expression of EphrinB2 in DPSCs resulted in significant upregulation of Musashi1 and NCAM gene expression, while treatment of DPSCs with recombinant EphB4-Fc protein led to significant upregulation of only Musashi1. Thus, it may be concluded that stimulation of forward EphrinB2-EphB4 signalling markedly inhibited neurogenesis in DPSCs, whereas suppression of this forward signalling pathway with peptide inhibitor specific to EphB4 promoted neurogenesis. Meanwhile, stimulation of reverse EphB4-EphrinB2 signalling only marginally enhanced the neural differentiation of DPSCs. The present findings indicate the potential application of peptide or small molecule inhibitors of EphrinB2 forward signalling in neural tissue engineering with DPSCs.

Electrical Stimulation Normalizes c-Fos Expression in the Deep Cerebellar Nuclei of Depressive-like Rats: Implication of Antidepressant Activity.

The electrical stimulation of specific brain targets has been shown to induce striking antidepressant effects. Despite that recent data have indicated that cerebellum is involved in emotional regulation, the mechanisms by which stimulation improved mood-related behaviors in the cerebellum remained largely obscure. Here, we investigated the stimulation effects of the ventromedial prefrontal cortex (vmPFC), nucleus accumbens (NAc), and lateral habenular nucleus on the c-Fos neuronal activity in various deep cerebellar and vestibular nuclei using the unpredictable chronic mild stress (CMS) animal model of depression. Our results showed that stressed animals had increased number of c-Fos cells in the cerebellar dentate and fastigial nuclei, as well as in the spinal vestibular nucleus. To examine the stimulation effects, we found that vmPFC stimulation significantly decreased the c-Fos activity within the cerebellar fastigial nucleus as compared to the CMS sham. Similarly, there was also a reduction of c-Fos expression in the magnocellular part of the medial vestibular nucleus in vmPFC- and NAc core-stimulated animals when compared to the CMS sham. Correlational analyses showed that the anxiety measure of home-cage emergence escape latency was positively correlated with the c-Fos neuronal activity of the cerebellar fastigial and magnocellular and parvicellular parts of the interposed nuclei in CMS vmPFC-stimulated animals. Interestingly, there was a strong correlation among activation in these cerebellar nuclei, indicating that the antidepressant-like behaviors were possibly mediated by the vmPFC stimulation-induced remodeling within the forebrain-cerebellar neurocircuitry.

Tetratricopeptide repeat domain 9A modulates anxiety-like behavior in female mice.

Tetratricopeptide repeat domain 9A (TTC9A) expression is abundantly expressed in the brain. Previous studies in TTC9A knockout (TTC9A-/-) mice have indicated that TTC9A negatively regulates the action of estrogen. In this study we investigated the role of TTC9A on anxiety-like behavior through its functional interaction with estrogen using the TTC9A-/- mice model. A battery of tests on anxiety-related behaviors was conducted. Our results demonstrated that TTC9A-/- mice exhibited an increase in anxiety-like behaviors compared to the wild type TTC9A+/+ mice. This difference was abolished after ovariectomy, and administration of 17-ß-estradiol benzoate (EB) restored this escalated anxiety-like behavior in TTC9A-/- mice. Since serotonin is well-known to be the key neuromodulator involved in anxiety behaviors, the mRNA levels of tryptophan hydroxylase (TPH) 1, TPH2 (both are involved in serotonin synthesis), and serotonin transporter (5-HTT) were measured in the ventromedial prefrontal cortex (vmPFC) and dorsal raphe nucleus (DRN). Interestingly, the heightened anxiety in TTC9A-/- mice under EB influence is consistent with a greater induction of TPH 2, and 5-HTT by EB in DRN that play key roles in emotion regulation. In conclusion, our data indicate that TTC9A modulates the anxiety-related behaviors through modulation of estrogen action on the serotonergic system in the DRN.

Pluripotent Human embryonic stem cell derived neural lineages for in vitro modelling of enterovirus 71 infection and therapy.

BACKGROUND: The incidence of neurological complications and fatalities associated with Hand, Foot & Mouth disease has increased over recent years, due to emergence of newly-evolved strains of Enterovirus 71 (EV71). In the search for new antiviral therapeutics against EV71, accurate and sensitive in vitro cellular models for preliminary studies of EV71 pathogenesis is an essential prerequisite, before progressing to expensive and time-consuming live animal studies and clinical trials. METHODS: This study thus investigated whether neural lineages derived from pluripotent human embryonic stem cells (hESC) can fulfil this purpose. EV71 infection of hESC-derived neural stem cells (NSC) and mature neurons (MN) was carried out in vitro, in comparison with RD and SH-SY5Y cell lines. RESULTS: Upon assessment of post-infection survivability and EV71 production by the various types, it was observed that NSC were significantly more susceptible to EV71 infection compared to MN, RD (rhabdomyosarcoma) and SH-SY5Y cells, which was consistent with previous studies on mice. The SP81 peptide had significantly greater inhibitory effect on EV71 production by NSC and MN compared to the cancer-derived RD and SH-SY5Y cell lines. CONCLUSIONS: Hence, this study demonstrates that hESC-derived neural lineages can be utilized as in vitro models for studying EV71 pathogenesis and for screening of antiviral therapeutics.

An Overview of Protocols for the Neural Induction of Dental and Oral Stem Cells In Vitro.

To date, various adult stem cells have been identified within the oral cavity, including dental pulp stem cells, dental follicle stem cells, stem cells from apical papilla, stem cells from human exfoliated deciduous teeth, periodontal ligament stem cells, and mesenchymal stem cells from the gingiva. All of these possess neurogenic potential due to their common developmental origin from the embryonic neural crest. Besides the relative ease of isolation of these adult stem cells from readily available biological waste routinely produced during dental treatment, these cells also possess the advantage of immune compatibility in autologous transplantation. In recent years, much interest has been focused on the derivation of neural lineages from these adult stem cells for therapeutic applications in the brain, spinal cord, and peripheral nerve regeneration. In addition, there are also promising nontherapeutic applications of stem cell-derived neurons in pharmacological and toxicological screening of neuroactive drugs, and for in vitro modeling of neurodevelopmental and neurodegenerative diseases. Hence, this review will critically examine the diverse array of in vitro neural induction protocols that have been devised for dental and oral-derived stem cells. These protocols are defined not only by the culture milieu comprising the basal medium plus growth factors, small molecules, and other culture supplements but also by the substrata/surface coatings utilized, the presence of multiple culture stages, the total culture duration, the initial seeding density, and whether the spheroid/neurosphere formation is being utilized to recapitulate the three-dimensional neural differentiation microenvironment that is naturally present physiologically in vivo.

Behavioral effects of deep brain stimulation of different areas of the Papez circuit on memory- and anxiety-related functions.

Deep brain stimulation (DBS) has gained interest as a potential therapy for advanced treatment-resistant dementia. However, possible targets for DBS and the optimal stimulation parameters are not yet clear. Here, we compared the effects of DBS of the CA1 sub-region of the hippocampus, mammillothalamic tract, anterior thalamic nucleus, and entorhinal cortex in an experimental rat model of dementia. Rats with scopolamine-induced amnesia were assessed in the object location task with different DBS parameters. Moreover, anxiety-related side effects were evaluated in the elevated zero maze and open field. After sacrifice, we applied c-Fos immunohistochemistry to assess which memory-related regions were affected by DBS. When comparing all structures, DBS of the entorhinal cortex and CA1 sub-region was able to restore memory loss when a specific set of stimulation parameters was used. No anxiety-related side effects were found following DBS. The beneficial behavioral performance of CA1 DBS rats was accompanied with an activation of cells in the anterior cingulate gyrus. Therefore, we conclude that acute CA1 DBS restores memory loss possibly through improved attentional and cognitive processes in the limbic cortex.

Neural Differentiation of Human Pluripotent Stem Cells for Nontherapeutic Applications: Toxicology, Pharmacology, and In Vitro Disease Modeling.

Human pluripotent stem cells (hPSCs) derived from either blastocyst stage embryos (hESCs) or reprogrammed somatic cells (iPSCs) can provide an abundant source of human neuronal lineages that were previously sourced from human cadavers, abortuses, and discarded surgical waste. In addition to the well-known potential therapeutic application of these cells in regenerative medicine, these are also various promising nontherapeutic applications in toxicological and pharmacological screening of neuroactive compounds, as well as for in vitro modeling of neurodegenerative and neurodevelopmental disorders. Compared to alternative research models based on laboratory animals and immortalized cancer-derived human neural cell lines, neuronal cells differentiated from hPSCs possess the advantages of species specificity together with genetic and physiological normality, which could more closely recapitulate in vivo conditions within the human central nervous system. This review critically examines the various potential nontherapeutic applications of hPSC-derived neuronal lineages and gives a brief overview of differentiation protocols utilized to generate these cells from hESCs and iPSCs.