Vitamin D Alleviates Cognitive Dysfunction by Activating the VDR/ERK1/2 Signaling Pathway in an Alzheimer’s Disease Mouse Model

2020 ◽  
Vol 27 (4) ◽  
pp. 178-185
Author(s):  
Zheng Bao ◽  
Xue Wang ◽  
Yuhong Li ◽  
Fumin Feng
Keyword(s):  
Vitamin D ◽  
Cognitive Impairment ◽  
Mouse Model ◽  
Signaling Pathway ◽  
Learning And Memory ◽  
Hippocampal Neurons ◽  
Morphological Changes ◽  
Active Form ◽  
Biologically Active ◽  
Neuroprotective Effects

Objective: Vitamin D (Vit D), a steroid hormone, has been linked to cognitive impairment and dementia, such as Alz­heimer’s disease (AD). 1, 25(OH)2D3 is the biologically active form of Vit D, which has been shown to have neuroprotective effects. This compound is being evaluated as an emerging therapeutic treatment in models of AD. Material and Methods: The present study was designed to investigate whether Vit D could alleviate cognitive impairment in an AD rat model by regulating the VDR/ERK1/2 signaling pathway. Adult male APPswe/PS1ΔE9 rats (n = 40) were randomly divided into 2 groups: the AD group and the Vit D + AD group (20 mice per group), and 40 C57BL/6J age-matched mice were separated into the control (CON) group and the Vit D + CON group (20 mice per group). The Morris water maze and object recognition tests were used to evaluate learning and memory functions of the mice. Hematoxylin and eosin staining was used to evaluate morphological changes in hippocampal neurons. Western blotting was used to evaluate the proteins responsible for these changes. Results: We found that Vit D improved learning and memory abilities and morphological defects in hippocampal neurons. Vit D decreased the gene expression of caspase-3 and Bax and increased the expression of Bcl-2. Vit D also increased the protein expression of VDR and p-ERK1 protein in AD mice. Conclusion: This study provides new clues about the mechanism by which Vit D exerts neuroprotective effects in an AD mouse model.

Rifampicin Suppresses Amyloid-β Accumulation Through Enhancing Autophagy in the Hippocampus of a Lipopolysaccharide-Induced Mouse Model of Cognitive Decline

2020 ◽  
pp. 1-14
Author(s):  
Lihong Zhu ◽  
Qiongru Yuan ◽  
Zhaohao Zeng ◽  
Ruiyi Zhou ◽  
Rixin Luo ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mouse Model ◽  
Hippocampal Neurons ◽  
Cognitive Impairments ◽  
Amyloid Β ◽  
Underlying Mechanism ◽  
Autophagosome Formation ◽  
Neuroprotective Effects ◽  
Biochemical Assays ◽  
Cognitive Sequelae

Background: Alzheimer’s disease (AD) is characterized by amyloid-β (Aβ) deposition. The metabolism of Aβ is critically affected by autophagy. Although rifampicin is known to mediate neuroinflammation, the underlying mechanism by which rifampicin regulates the cognitive sequelae remains unknown. Objective: Based on our previous findings that rifampicin possesses neuroprotective effects on improving cognitive function after neuroinflammation, we aimed to examine in this study whether rifampicin can inhibit Aβ accumulation by enhancing autophagy in a mouse model of lipopolysaccharide (LPS)-induced cognitive impairment. Methods: Adult C57BL/6 mice were intraperitoneally injected with rifampicin, chloroquine, and/or LPS every day for 7 days. Pathological and biochemical assays and behavioral tests were performed to determine the therapeutic effect and mechanism of rifampicin on the hippocampus of LPS-induced mice. Results: We found that rifampicin ameliorated cognitive impairments in the LPS-induced mice. In addition, rifampicin attenuated the inhibition of autophagosome formation, suppressed the accumulation of Aβ1–42, and protected the hippocampal neurons against LPS-induced damage. Our results further demonstrated that rifampicin improved the neurological function by promoting autophagy through the inhibition of Akt/mTOR/p70S6K signaling pathway in the hippocampus of LPS-induced mice. Conclusion: Rifampicin ameliorates cognitive impairment by suppression of Aβ1–42 accumulation through inhibition of Akt/mTOR/p70S6K signaling and enhancement of autophagy in the hippocampus of LPS-induced mice.

scholarly journals Age-Related Cognitive Impairment: Role of Reduced Synaptobrevin-2 Levels in Deficits of Memory and Synaptic Plasticity

2019 ◽  
Vol 75 (9) ◽  
pp. 1624-1632 ◽  
Author(s):  
Albert Orock ◽  
Sreemathi Logan ◽  
Ferenc Deak
Keyword(s):  
Cognitive Impairment ◽  
Synaptic Plasticity ◽  
Learning And Memory ◽  
Hippocampal Neurons ◽  
Long Term Potentiation ◽  
Receptor Protein ◽  
Protein Levels ◽  
Ca1 Region ◽  
Age Related ◽  
Term Potentiation

AbstractCognitive impairment in the aging population is quickly becoming a health care priority, for which currently no disease-modifying treatment is available. Multiple domains of cognition decline with age even in the absence of neurodegenerative diseases. The cellular and molecular changes leading to cognitive decline with age remain elusive. Synaptobrevin-2 (Syb2), the major vesicular SNAP receptor protein, highly expressed in the cerebral cortex and hippocampus, is essential for synaptic transmission. We have analyzed Syb2 protein levels in mice and found a decrease with age. To investigate the functional consequences of lower Syb2 expression, we have used adult Syb2 heterozygous mice (Syb2+/−) with reduced Syb2 levels. This allowed us to mimic the age-related decrease of Syb2 in the brain in order to selectively test its effects on learning and memory. Our results show that Syb2+/− animals have impaired learning and memory skills and they perform worse with age in the radial arm water maze assay. Syb2+/− hippocampal neurons have reduced synaptic plasticity with reduced release probability and impaired long-term potentiation in the CA1 region. Syb2+/− neurons also have lower vesicular release rates when compared to WT controls. These results indicate that reduced Syb2 expression with age is sufficient to cause cognitive impairment.

scholarly journals Key Vitamin D Target Genes with Functions in the Immune System

Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1140 ◽  
Author(s):  
Oona Koivisto ◽  
Andrea Hanel ◽  
Carsten Carlberg
Keyword(s):  
Vitamin D ◽  
Adaptive Immunity ◽  
Vitamin D3 ◽  
Target Genes ◽  
Mononuclear Cells ◽  
Active Form ◽  
Biologically Active ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Innate And Adaptive Immunity

The biologically active form of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), modulates innate and adaptive immunity via genes regulated by the transcription factor vitamin D receptor (VDR). In order to identify the key vitamin D target genes involved in these processes, transcriptome-wide datasets were compared, which were obtained from a human monocytic cell line (THP-1) and peripheral blood mononuclear cells (PBMCs) treated in vitro by 1,25(OH)2D3, filtered using different approaches, as well as from PBMCs of individuals supplemented with a vitamin D3 bolus. The led to the genes ACVRL1, CAMP, CD14, CD93, CEBPB, FN1, MAPK13, NINJ1, LILRB4, LRRC25, SEMA6B, SRGN, THBD, THEMIS2 and TREM1. Public epigenome- and transcriptome-wide data from THP-1 cells were used to characterize these genes based on the level of their VDR-driven enhancers as well as the level of the dynamics of their mRNA production. Both types of datasets allowed the categorization of the vitamin D target genes into three groups according to their role in (i) acute response to infection, (ii) infection in general and (iii) autoimmunity. In conclusion, 15 genes were identified as major mediators of the action of vitamin D in innate and adaptive immunity and their individual functions are explained based on different gene regulatory scenarios.

Altered regulation of cytosolic Ca2+ concentration in dendritic cells from klotho hypomorphic mice

2013 ◽  
Vol 305 (1) ◽  
pp. C70-C77 ◽  
Author(s):  
Ekaterina Shumilina ◽  
Meerim K. Nurbaeva ◽  
Wenting Yang ◽  
Evi Schmid ◽  
Kalina Szteyn ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Vitamin D ◽  
Dendritic Cells ◽  
Active Form ◽  
Biologically Active ◽  
Deficient Diet ◽  
Dihydroxyvitamin D3 ◽  
Mhc Ii ◽  
Macrophage Colony ◽  
Antigen Presenting

The function of dendritic cells (DCs), antigen-presenting cells regulating naïve T-cells, is regulated by cytosolic Ca2+ concentration ([Ca2+]i). [Ca2+]i is increased by store-operated Ca2+ entry and decreased by K+-independent (NCX) and K+-dependent (NCKX) Na+/Ca2+ exchangers. NCKX exchangers are stimulated by immunosuppressive 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], the biologically active form of vitamin D. Formation of 1,25(OH)2D3 is inhibited by the antiaging protein Klotho. Thus 1,25(OH)2D3 plasma levels are excessive in Klotho-deficient mice ( klotho hm). The present study explored whether Klotho deficiency modifies [Ca2+]i regulation in DCs. DCs were isolated from the bone marrow of klotho hm mice and wild-type mice ( klotho+/+) and cultured for 7–9 days with granulocyte-macrophage colony-stimulating factor. According to major histocompatibility complex II (MHC II) and CD86 expression, differentiation and lipopolysaccharide (LPS)-induced maturation were similar in klotho hm DCs and klotho+/+ DCs. However, NCKX1 membrane abundance and NCX/NCKX-activity were significantly enhanced in klotho hm DCs. The [Ca2+]i increase upon acute application of LPS (1 μg/ml) was significantly lower in klotho hm DCs than in klotho+/+ DCs, a difference reversed by the NCKX blocker 3′,4′-dichlorobenzamyl (DBZ; 10 μM). CCL21-dependent migration was significantly less in klotho hm DCs than in klotho+/+ DCs but could be restored by DBZ. NCKX activity was enhanced by pretreatment of klotho+/+ DC precursors with 1,25(OH)2D3 the first 2 days after isolation from bone marrow. Feeding klotho hm mice a vitamin D-deficient diet decreased NCKX activity, augmented LPS-induced increase of [Ca2+]i, and enhanced migration of klotho hm DCs, thus dissipating the differences between klotho hm DCs and klotho+/+ DCs. In conclusion, Klotho deficiency upregulates NCKX1 membrane abundance and Na+/Ca2+-exchange activity, thus blunting the increase of [Ca2+]i following LPS exposure and CCL21-mediated migration. The effects are in large part due to excessive 1,25(OH)2D3 formation.

scholarly journals Vitamin D Treatment Sequence Is Critical for Transcriptome Modulation of Immune Challenged Primary Human Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Henna-Riikka Malmberg ◽  
Andrea Hanel ◽  
Mari Taipale ◽  
Sami Heikkinen ◽  
Carsten Carlberg
Keyword(s):  
Vitamin D ◽  
Mononuclear Cells ◽  
Fungal Infections ◽  
Human Peripheral Blood ◽  
Active Form ◽  
Biologically Active ◽  
Treatment Sequence ◽  
Peripheral Blood Mononuclear ◽  
Lps Challenge ◽  
Immune Challenges

Microbe-associated molecular patterns, such as lipopolysaccharide (LPS) and β-glucan (BG), are surrogates of immune challenges like bacterial and fungal infections, respectively. The biologically active form of vitamin D, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), supports the immune system in its fight against infections. This study investigated significant and prominent changes of the transcriptome of human peripheral blood mononuclear cells that immediately after isolation are exposed to 1,25(OH)2D3-modulated immune challenges over a time frame of 24-48 h. In this in vitro study design, most LPS and BG responsive genes are downregulated and their counts are drastically reduced when cells are treated 24 h after, 24 h before or in parallel with 1,25(OH)2D3. Interestingly, only a 1,25(OH)2D3 pre-treatment of the LPS challenge results in a majority of upregulated genes. Based on transcriptome-wide data both immune challenges display characteristic differences in responsive genes and their associated pathways, to which the actions of 1,25(OH)2D3 often oppose. The joined BG/1,25(OH)2D3 response is less sensitive to treatment sequence than that of LPS/1,25(OH)2D3. In conclusion, the functional consequences of immune challenges are significantly modulated by 1,25(OH)2D3 but largely depend on treatment sequence. This may suggest that a sufficient vitamin D status before an infection is more important than vitamin D supplementation afterwards.

scholarly journals Shikonin Attenuates Chronic Cerebral Hypoperfusion-Induced Cognitive Impairment by Inhibiting Apoptosis via PTEN/Akt/CREB/BDNF Signaling

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yanqiu Jia ◽  
Zhe Li ◽  
Tianjun Wang ◽  
Mingyue Fan ◽  
Jiaxi Song ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Signaling Pathway ◽  
Hippocampal Neurons ◽  
Sham Group ◽  
Chronic Cerebral Hypoperfusion ◽  
Cerebral Hypoperfusion ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Vehicle Group ◽  
Nissl Staining ◽  
Bdnf Signaling

Shikonin (SK) exerts neuroprotective effects; however, to date, its protective effect against chronic cerebral hypoperfusion- (CCH-) induced vascular dementia (VaD) has not been investigated. Therefore, the current study investigated whether SK could mitigate the cognitive deficits caused by CCH. The effects of SK treatment on the PTEN/Akt/CREB/BDNF signaling pathway and apoptosis in hippocampal neurons were examined in a rat model of VaD established via bilateral common carotid artery occlusion (BCCAO). Fifty-two rats were randomly divided into 4 groups: sham, vehicle, SK-L (10 mg/kg SK per day), and SK-H (25 mg/kg SK per day). SK was regularly administered by gavage for 2 weeks. The results of the water maze test revealed that the escape latency in the vehicle group was significantly longer than that in the sham group, and rats in the vehicle group spent a smaller proportion of time in the target quadrant than those in the sham group. SK treatment reduced the escape latencies and increased the proportion of time spent in the target quadrant. Nissl staining showed morphological damage in the CA1 areas of the hippocampus in the vehicle group. SK treatment alleviated the injuries to hippocampal neurons. Western blot analysis showed higher p-PTEN and lower p-Akt, p-CREB, and BDNF expression in the vehicle group than in the sham group. SK administration reversed the upregulation of p-PTEN and the downregulation of p-Akt, p-CREB, and BDNF. The number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling- (TUNEL-) positive cells in the hippocampal CA1 region of the vehicle group was significantly increased. Treatment with SK decreased the number of positive cells. Furthermore, as marker proteins of apoptosis, bcl-2 expression was decreased and bax expression was increased; thus, the ratio of bcl-2/bax was decreased in the vehicle group. SK treatment upregulated the expression of bcl-2 and downregulated the expression of bax, thereby elevating the bcl-2/bax ratio. Moreover, the aforementioned effects of SK were dose-dependent. The effect of 25 mg/kg per day was more obvious than that of 10 mg/kg per day. In conclusion, SK inhibited hippocampal neuronal apoptosis to protect against CCH-induced injury by regulating the PTEN/Akt/CREB/BDNF signaling pathway, consequently improving cognitive impairment.

scholarly journals Vitamin D Enhances Radiosensitivity of Colorectal Cancer by Reversing Epithelial-Mesenchymal Transition

2021 ◽  
Vol 9 ◽  
Author(s):  
Xinyue Yu ◽  
Qian Wang ◽  
Baocai Liu ◽  
Ning Zhang ◽  
Guanghui Cheng
Keyword(s):  
Colorectal Cancer ◽  
Vitamin D ◽  
Epithelial Mesenchymal Transition ◽  
Active Form ◽  
Plasminogen Activator Inhibitor ◽  
Biologically Active ◽  
Plasminogen Activator Inhibitor 1 ◽  
Mesenchymal Transition

Colorectal cancer (CRC) is often resistant to conventional therapies. Previous studies have reported the anticancer effects of vitamin D in several cancers, its role in radiotherapy (RT) remains unknown. We found that 1α, 25-dihydroxyvitamin D3 (VD3), the biologically active form of vitamin D, had antitumor effect on CRC and sensitized CRC cells to ionizing radiation (IR). VD3 demonstrated synergistic effect in combination with IR, which were detected by colony formation and cell proliferation assay. Radiosensitivity restoration induced by VD3 was associated with a series of phenotypes, including apoptosis, autophagy, and epithelial-mesenchymal transition (EMT). Using proteomics, “regulation of cell migration” and “cadherin” were found to be obviously enriched GO terms. Moreover, cystatin D and plasminogen activator inhibitor-1 (PAI-1), the differentially expressed proteins, were associated with EMT. Next, we confirmed the contributions of these two genes in enhancing IR sensitivity of CRC cells upon inhibition of EMT. As determined by proteomics, the mechanism underlying such sensitivity involved partially block of JAK/STAT3 signaling pathway. Furthermore, VD3 also elicited sensitization to RT in xenograft CRC models without additional toxicity. Our study revealed that VD3 was able to act in synergy with IR both in vitro and in vivo and could also confer radiosensitivity by regulating EMT, thereby providing a novel insight for elevating the efficacy of therapeutic regimens.

scholarly journals Impact of Epigenetics on Complications of Fanconi Anemia: The Role of Vitamin D-Modulated Immunity

Nutrients ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1355
Author(s):  
Eunike Velleuer ◽  
Carsten Carlberg
Keyword(s):  
Vitamin D ◽  
Fanconi Anemia ◽  
Bone Marrow Failure ◽  
Active Form ◽  
Cellular Growth ◽  
Biologically Active ◽  
Fine Tuning ◽  
Dihydroxyvitamin D3 ◽  
Increased Risk ◽  
The Individual

Fanconi anemia (FA) is a rare disorder with the clinical characteristics of (i) specific malformations at birth, (ii) progressive bone marrow failure already during early childhood and (iii) dramatically increased risk of developing cancer in early age, such as acute myeloid leukemia and squamous cell carcinoma. Patients with FA show DNA fragility due to a defect in the DNA repair machinery based on predominately recessive mutations in 23 genes. Interestingly, patients originating from the same family and sharing an identical mutation, frequently show significant differences in their clinical presentation. This implies that epigenetics plays an important role in the manifestation of the disease. The biologically active form of vitamin D, 1α,25-dihydroxyvitamin D3 controls cellular growth, differentiation and apoptosis via the modulation of the immune system. The nuclear hormone activates the transcription factor vitamin D receptor that affects, via fine-tuning of the epigenome, the transcription of >1000 human genes. In this review, we discuss that changes in the epigenome, in particular in immune cells, may be central for the clinical manifestation of FA. These epigenetic changes can be modulated by vitamin D suggesting that the individual FA patient’s vitamin D status and responsiveness are of critical importance for disease progression.

scholarly journals Upregulation of Neuronal Rheb(S16H) for Hippocampal Protection in the Adult Brain

2020 ◽  
Vol 21 (6) ◽  
pp. 2023 ◽  
Author(s):  
Gyeong Joon Moon ◽  
Minsang Shin ◽  
Sang Ryong Kim
Keyword(s):  
Hippocampal Neurons ◽  
Energy Homeostasis ◽  
Therapeutic Potential ◽  
Active Form ◽  
Mammalian Target Of Rapamycin ◽  
Adult Brain ◽  
Acid Uptake ◽  
Neuroprotective Effects ◽  
Virus Serotype ◽  
Mtorc1 Signaling

Ras homolog protein enriched in brain (Rheb) is a key activator of mammalian target of rapamycin complex 1 (mTORC1). The activation of mTORC1 by Rheb is associated with various processes such as protein synthesis, neuronal growth, differentiation, axonal regeneration, energy homeostasis, autophagy, and amino acid uptake. In addition, Rheb–mTORC1 signaling plays a crucial role in preventing the neurodegeneration of hippocampal neurons in the adult brain. Increasing evidence suggests that the constitutive activation of Rheb has beneficial effects against neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). Our recent studies revealed that adeno-associated virus serotype 1 (AAV1) transduction with Rheb(S16H), a constitutively active form of Rheb, exhibits neuroprotective properties through the induction of various neurotrophic factors, promoting neurotrophic interactions between neurons and astrocytes in the hippocampus of the adult brain. This review provides compelling evidence for the therapeutic potential of AAV1–Rheb(S16H) transduction in the hippocampus of the adult brain by exploring its neuroprotective effects and mechanisms.

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