Vitamin A supplementation ameliorates motor incoordination via modulating RORα in the cerebellum in a valproic acid-treated rat autism model with vitamin A deficiency.

Motor dysfunctions are common comorbidities among autism spectrum disorder (ASD) patients. Abnormal cerebellar development throughout critical periods may have an effect on motor functions and result in motor impairments. Vitamin A (VA) plays a crucial role in the developing process of the nervous system. The correlation of VA deficiency (VAD) and ASD with motor dysfunctions, however, is not clear. Therefore, we built rat models with different VA levels based on the valproic acid (VPA)-treated autism model. ASD rats with VAD showed aggravated motor coordination abnormalities, Purkinje cell loss and impaired dendritic arborization of Purkinje cells compared to ASD rats with normal VA levels (VA normal, VAN). Additionally, the expression levels of retinoid-related orphan receptor α (RORα) and retinoic acid receptor α (RARα) were lower in the cerebellum of ASD rats with VAD than in those of ASD rats with VAN. VA supplementation (VAS) effectively improved motor coordination and cerebellar Purkinje cell abnormalities in ASD rats with VAD. Furthermore, the results of chromatin immunoprecipitation (ChIP) assays confirmed that the enrichment of RARα was detected on the RORα promoter in the cerebellum and that VAS could upregulate the binding capacity of RARα for RORα promoters. These results showed that VAD in autism might result in cerebellar impairments and be a factor aggravating a subtype of ASD with motor comorbidities. The therapeutic effect of VAS on motor deficits and Purkinje neuron impairments in autism might be due to the regulation of RORα by RARα.

Alteration of the Retinoid Acid-CBP Signaling Pathway in Neural Crest Induction Contributes to Enteric Nervous System Disorder.

Hirschsprung Disease (HSCR) and/or hypoganglionosis are common pediatric disorders that arise from developmental deficiencies of enteric neural crest cells (ENCCs). Retinoid acid (RA) signaling has been shown to affect neural crest (NC) development. However, the mechanisms underlying RA deficiency-induced HSCR or hypoganglionosis are not well-defined. In this report, we found that in HSCR patient bowels, the RA nuclear receptor RARα and its interacting coregulator CREB-binding protein (CBP) were expressed in enteric neural plexuses in the normal ganglionic segment. However, the expression of these two genes was significantly inhibited in the pathological aganglionic segment. In a Xenopus laevis animal model, endogenous RARα interacted with CBP and was expressed in NC territory. Morpholino-mediated knockdown of RARα blocked expression of the NC marker genes Sox10 and FoxD3 and inhibited NC induction. The morphant embryos exhibited reduced nervous cells in the gastrointestinal anlage, a typical enteric nervous deficiency-associated phenotype. Injection of CBP mRNA rescued NC induction and reduced enteric nervous deficiency-associated phenotypes. Our work demonstrates that RARα regulates Sox10 expression via CBP during NC induction, and alteration of the RA-CBP signaling pathway may contribute to the development of enteric nervous system disorders.

Vitamin A Deficiency Induces Autistic-Like Behaviors in Rats by Regulating the RARß-CD38-Oxytocin Axis in the Hypothalamus.

SCOPE: Vitamin A (VA) is an essential nutrient for the development of the brain. We previously found that children with autism spectrum disorder (ASD) have a significant rate of VA deficiency (VAD). In the current study, we aim to determine whether VAD is a risk factor for the generation of autistic-like behaviors via the transcription factor retinoic acid receptor beta (RARß)-regulated cluster of differentiation 38 (CD38)-oxytocin (OXT) axis. METHODS AND RESULTS: Gestational VAD or VA supplementation (VAS) rat models are established, and the autistic-like behaviors in the offspring rats are investigated. The different expression levels of RARß and CD38 in hypothalamic tissue and serum retinol and OXT concentration are tested. Primary cultured rat hypothalamic neurons are treated with all-trans retinoic acid (atRA), and recombinant adenoviruses carrying the rat RARß (AdRARß) or RNA interference virus RARß-siRNA (siRARß) are used to infect neurons to change RARß signal. Western blotting, chromatin immunoprecipitation (ChIP), and intracellular Ca2+ detections are used to investigate the primary regulatory mechanism of RARß in the CD38-OXT signaling pathway. We found that gestational VAD increases autistic-like behaviors and decreases the expression levels of hypothalamic RARß and CD38 and serum OXT levels in the offspring. VAS ameliorates these autistic-like behaviors and increases the expression levels of RARß, CD38, and OXT in the gestational VAD pups. In vitro, atRA increases the Ca2+ excitability of neurons, which might further promote the release of OXT. Different CD38 levels are induced in the neurons by infection with different RARß adenoviruses. Furthermore, atRA enhances the binding of RARß to the proximal promoter of CD38, indicating a potential upregulation of CD38 transcriptional activity by RARß. CONCLUSIONS: Gestational VAD might be a risk factor for autistic-like behaviors due to the RARß signal suppression of CD38 expression in the hypothalamus of the offspring, which improves with VAS during the early-life period. The nutritional status during pregnancy and the early-life period is important in rats.

Effect of vitamin A supplementation on gut microbiota in children with autism spectrum disorders - a pilot study.

BACKGROUND: Dysbiosis of gut microbiota are commonly reported in autism spectrum disorder (ASD) and may contribute to behavioral impairment. Vitamin A (VA) plays a role in regulation of gut microbiota. This study was performed to investigate the role of VA in the changes of gut microbiota and changes of autism functions in children with ASD. RESULTS: Sixty four, aged 1 to 8 years old children with ASD completed a 6-month follow-up study with VA intervention. High-performance liquid chromatography was used to assess plasma retinol levels. The Autism Behaviour Checklist (ABC), Childhood Autism Rating Scale (CARS) and Social Responsiveness Scale (SRS) were used to assess autism symptoms. CD38 and acid-related orphan receptor alpha (RORA) mRNA levels were used to assess autism-related biochemical indicators' changes. Evaluations of plasma retinol, ABC, CARS, SRS, CD38 and RORA mRNA levels were performed before and after 6 months of intervention in the 64 children. Illumina MiSeq for 16S rRNA genes was used to compare the differences in gut microbiota before and after 6 months of treatment in the subset 20 of the 64 children. After 6 months of intervention, plasma retinol, CD38 and RORA mRNA levels significantly increased (all P < 0.05); the scores of ABC, CARS and SRS scales showed no significant differences (all P > 0.05) in the 64 children. Meanwhile, the proportion of Bacteroidetes/Bacteroidales significantly increased and the proportion of Bifidobacterium significantly decreased in the subgroup of 20 (all false discovery rate (FDR) q < 0.05). CONCLUSIONS: Bacteroidetes/Bacteroidales were the key taxa related to VA. Moreover, VA played a role in the changes in autism biomarkers. It remains unclear whether the VA concentration is associated with autism symptoms. TRIAL REGISTRATION: The study protocol was peer reviewed and approved by the institutional review board of Children's Hospital, Chongqing Medical University in 2013 and retrospectively registered in Chinese Clinical Trial Registry (ChiCTR) on November 6, 2014 (TRN: ChiCTR-ROC-14005442 ).

Correlation between Nutrition and Symptoms: Nutritional Survey of Children with Autism Spectrum Disorder in Chongqing, China.

Restricted diets and inadequate nutrient intake of children with autism spectrum disorder (ASD) have been reported. This study examined the nutritional statuses of children with ASD and the relationships between their behaviors and nutritional intake. A total of 154 children with ASD (age = 5.21 ± 1.83 years) and 73 typically-developing (TD) children (age = 4.83 ± 0.84 years) from Chongqing, China, were enrolled. The severity of ASD was evaluated using the Childhood Autism Rating Scale (CARS). The serum ferritin, folate, vitamin B12, 25(OH) vitamin D, and vitamin A concentrations in the children with ASD were determined. All participants underwent anthropometric examinations, dietary assessments, and questionnaire assessments about their feeding behaviors, and gastrointestinal symptoms. The ZHA, ZWA, and ZBMIA were found to be significantly lower in the children with ASD compared with those without ASD. In addition, the percentages of children exhibiting severe picky eating and severe resistance to new foods, as well as those with a reported general impression of severe eating problems and constipation, were higher among the children with ASD. These children consumed significantly fewer macronutrients compared with the children without ASD. In addition, the children with ASD had the highest rate of vitamin A deficiency, followed by iron deficiency. After adjusting for sex, the vitamin A concentration was found to be negatively correlated with the CARS score (rs = -0.222, p = 0.021). No correlation between the ferritin, folate, vitamin D, or vitamin B12 concentration and the CARS score was found. These results suggest that reduced macronutrient intakes, severe feeding behavior issues, constipation, and vitamin A deficiency are quite common among children with ASD. Further, a low serum vitamin A level may be a risk factor for symptoms of ASD. However, the underlying mechanism should be further studied.

Endogenous IL-6 of mesenchymal stem cell improves behavioral outcome of hypoxic-ischemic brain damage neonatal rats by supressing apoptosis in astrocyte.

Mesenchymal stem cell (MSC) transplantation reduces the neurological impairment caused by hypoxic-ischemic brain damage (HIBD) via immunomodulation. In the current study, we found that MSC transplantation improved learning and memory function and enhanced long-term potentiation in neonatal rats subjected to HIBD and the amount of IL-6 released from MSCs was far greater than that of other cytokines. However, the neuroprotective effect of MSCs infected with siIL-6-transduced recombinant lentivirus (siIL-6 MSCs) was significantly weakened in the behavioural tests and electrophysiological analysis. Meanwhile, the hippocampal IL-6 levels were decreased following siIL-6 MSC transplantation. In vitro, the levels of IL-6 release and the levels of IL-6R and STAT3 expression were increased in both primary neurons and astrocytes subjected to oxygen and glucose deprivation (OGD) following MSCs co-culture. The anti-apoptotic protein Bcl-2 was upregulated and the pro-apoptotic protein Bax was downregulated in OGD-injured astrocytes co-cultured with MSCs. However, the siIL-6 MSCs suppressed ratio of Bcl-2/Bax in the injured astrocytes and induced apoptosis number of the injured astrocytes. Taken together, these data suggest that the neuroprotective effect of MSC transplantation in neonatal HIBD rats is partly mediated by IL-6 to enhance anti-apoptosis of injured astrocytes via the IL-6/STAT3 signaling pathway.

[Acetylated Histone Expressions of the Primary Hippocampal Neurons in Rats Reduced by siCBP Lentivirus].

This study aims to construct the recombinant lentivirus vector containing specific small interfering RNA (siRNA) targeting rat CREB binding protein(CBP)gene and to identify its function of inhibiting the expressions of acetylated histone in primarily cultured hippocampal neurons. Firstly, we constructed four kinds of recombinant lentivirus siCBP. And then we used them to infect the primarily cultured hippocampal neurons, and performed real-time PCR, western blot respectively to detect the expressions of CBP. Afterwards, the most effective lentivirus siCBP was used to infect the primarily cultured hippocampal neurons, and then the HAT activity and protein expressions of acetylated histone Ac-H3, Ac-H4 of the neurons were examined. By using PCR, endonuclease cutting and gene sequencing, we confirmed that the target genes were correctly cloned in lentivirus vector. Besides, CBP mRNA and protein expressions in neurons were found to be with varying degrees of decreases after infections of the four kinds of lentivirus siCBP. Furthermore, the representative and most effective lentivirus GR806 could effectively inhibit the HAT activity and the protein expressions of Ac-H3, Ac-H4 in neurons. It provides the experimental basis for the subsequent application of siCBP to clarify the effects and corresponding molecular mechanism of the CBP-dependent histone acetylation on learning and memory function in hippocampus.

Vitamin A deficiency impairs spatial learning and memory: the mechanism of abnormal CBP-dependent histone acetylation regulated by retinoic acid receptor alpha.

Vitamin A (VA) is an essential micronutrient. Numerous studies have confirmed that VA deficiency (VAD) leads to a decline in learning and memory function. Our previous studies have demonstrated that retinoic acid nuclear receptor α (RARα) in the hippocampus plays a crucial role in learning and memory, but the exact mechanism for this process is unclear. Epigenetic modifications, particularly histone acetylation, are involved in nervous system development, learning and memory function, and the pathogenesis of neurodegenerative diseases. Histone acetyltransferases (HATs), such as CREB-binding protein (CBP), E1A-binding protein p300 (p300), and p300/CBP-associated factor (PCAF), are critical for regulating memory function. The current study uses RARα and CBP as examples to study the connections between the RA signaling pathway and histone acetylation modification and to reveal the epigenetic mechanism in VAD-induced learning and memory impairment. This study examined the expression of RARα, HATs, acetylated histone H3/H4, and memory-related genes (Zif268, cFos, FosB), as well as the interaction of RARα and CBP in the hippocampus of 8-week-old rats. Additionally, the changes shown in vivo were further assessed in primary cultured neurons with the inhibition or overexpression of RARα. We found significantly lower levels of histone acetylation in the VAD rats. Furthermore, this downregulation, which impairs learning and memory, is induced by the dysregulation of CBP-dependent histone acetylation that is mediated by RARα. This work provides a solid theoretical foundation and experimental basis for the importance of ensuring sufficient nutritional VA during pregnancy and early life to prevent impairments of learning and memory in adulthood.

Spatiotemporal expression of HDAC2 during the postnatal development of the rat hippocampus.

BACKGROUND: Histone acetylation, which is a chromatin modification of histone tails, can dynamically regulate the expression of various genes in normal development. HDAC2 is a negative regulatory factor of acetylation and closely related to learning and memory. NSE is a nerve marker and vital for maintaining physiological functions in nervous system. Currently, few studies associated with the expression pattern of HDAC2 in postnatal rat hippocampus have been reported. This study aimed to explore the temporal and spatial expression pattern of HDAC2, helping to reveal the expression characteristics of HDAC2 during postnatal neuronal maturation. MATERIALS AND METHODS: With NSE as a biomarker of neuronal maturation at postnatal days 1, 3, 7 and weeks 2, 4, and 8 (P1D, P3D, P7D, P2W, P4W, P8W), the expression patterns of HDAC2 in rat hippocampus were examined using real-time PCR and western blotting. Additionally, the subcellular distribution of HDAC2 was analysed by immunofluorescence. RESULTS: We found that HDAC2 was highly expressed in the neonatal period and decreased gradually. HDAC2 expression was widely distributed in neurons of hippocampal CA1, CA3 and DG regions and gradually shifted from the nucleus to the cytoplasm during postnatal development. Altogether, the expression of HDAC2 decreased gradually with different subcellular localizations throughout development. CONCLUSIONS: The observed results indicate that the expression levels of HDAC2 become lower and with different subcellular localizations in neurons during hippocampal neuronal maturation, suggesting the specific expression characteristics of HDAC2 might play an important role during postnatal learning-memory function and development.

Retinoic acid receptor beta mediates all-trans retinoic acid facilitation of mesenchymal stem cells neuronal differentiation.

All-trans retinoic acid plays an important role in nervous system development. However, the effects of all-trans retinoic acid on the neuronal differentiation of mesenchymal stem cells and the mechanisms through which this differentiation takes place are still poorly understood. Here, we investigated the biological effects of all-trans retinoic acid on the neuronal differentiation of mesenchymal stem cells and the signaling pathways that mediated these effects. We found that the neuronal differentiation efficiency of mesenchymal stem cells following all-trans retinoic acid pre-induction was greater and the axonal length was longer than was observed with mesenchymal stem cells that were not pre-induced. mRNA and protein levels of the neural-markers Nestin, NSE, MAP-2, Tau and Tuj1 were stronger in neural-like cells derived from all-trans retinoic acid-pretreated mesenchymal stem cells than in those not pre-induction. Interestingly, the neuronal excitability of differentiated neural-like cells exhibited the same patterns between these two groups. Clear expression of retinoic acid receptor alpha and gamma in mesenchymal stem cells was observed, while retinoic acid receptor beta was barely detected. However, retinoic acid receptor beta expression in mesenchymal stem cells after neuronal induction increased dramatically, in contrast with retinoic acid receptor alpha and gamma expression, and retinoic acid receptor beta expression in mesenchymal stem cells receiving all-trans retinoic acid pre-induction was even stronger. Next, retinoic acid receptor alpha, beta and gamma were over-expressed by recombinant adenovirus infection prior to neuronal induction. Retinoic acid receptor alpha and gamma over-expression did not impact the neuronal differentiation of mesenchymal stem cells. However, retinoic acid receptor beta over-expression promoted neuronal differentiation to a similar level as observed following all-trans retinoic acid pre-induction. The neuronal differentiation promoting effects of all-trans retinoic acid on mesenchymal stem cells could be inhibited by siRNA silencing of retinoic acid receptor beta and by LE135, an inhibitor of retinoic acid receptor beta. Taken together, these results suggest that all-trans retinoic acid pre-induction facilitates the neuronal differentiation of mesenchymal stem cells. These facilitation effects are achieved by activating the retinoic acid receptor beta signaling pathway.

Immortalized mesenchymal stem cells: an alternative to primary mesenchymal stem cells in neuronal differentiation and neuroregeneration associated studies.

BACKGROUND: Mesenchymal stem cells (MSCs) can be induced to differentiate into neuronal cells under appropriate cellular conditions and transplanted in brain injury and neurodegenerative diseases animal models for neuroregeneration studies. In contrast to the embryonic stem cells (ESCs), MSCs are easily subject to aging and senescence because of their finite ability of self-renewal. MSCs senescence seriously affected theirs application prospects as a promising tool for cell-based regenerative medicine and tissue engineering. In the present study, we established a reversible immortalized mesenchymal stem cells (IMSCs) line by using SSR#69 retrovirus expressing simian virus 40 large T (SV40T) antigen as an alternative to primary MSCs. METHODS: The retroviral vector SSR#69 expressing simian virus 40 large T (SV40T) antigen was used to construct IMSCs. IMSCs were identified by flow cytometry to detect cell surface makers. To investigate proliferation and differentiation potential of IMSCs, cell growth curve determination and mesodermal trilineage differentiation tests were performed. Neuronal differentiation characteristics of IMSCs were detected in vitro. Before IMSCs transplantation, we excluded its tumorigenicity in nude mice firstly. The Morris water maze tests and shuttle box tests were performed five weeks after HIBD models received cells transplantation therapy. RESULTS: In this study, reversible IMSCs were constructed successfully and had the similar morphology and cell surface makers as primary MSCs. IMSCs possessed better ability of proliferation and anti-senescence compared with primary MSCs, while maintained multilineage differentiation capacity. Neural-like cells derived from IMSCs had similar expressions of neural-specific genes, protein expression patterns and resting membrane potential (RMP) compared with their counterparts derived from primary MSCs. There was no bump formation in nude mice subcutaneously injected with IMSCs. IMSCs played same role as primary MSCs to improve learning ability and spatial memory of HIBD rats. CONCLUSIONS: IMSCs not only retain their features of primary MSCs but also possess the ability of high proliferation and anti-senescence. IMSCs can definitely be induced to differentiate into neuronal cells in vitro and take the place of primary MSCs for cell transplantation therapy without tumorigenesis in vivo. The stable cell line is particularly useful and valuable as an alternative to MSCs in neuronal differentiation and neuroregeneration associated studies.