apoE mRNA Research Articles

MULTİPLE SKLEROZ HASTALARINDA APOE GEN EKSPRESYONUNUN BELİRLENMESİ

OBJECTIVE: Apolipoprotein E (ApoE) is a glycoprotein that functions as a ligand in receptor-mediated endocytosis of lipoprotein particles. There are studies showing the association of APOE with neurogenerative diseases such as Alzheimer's disease and multiple sclerosis (MS). The aim of this study was to investigate whether there is a relationship between APOE gene expression and MS.MATERIAL AND METHODS: To determine the effect of APOE gene expression on multiple sclerosis patients, we have included 35 MS patients and 20 healthy subjects into the study. The level of APOE mRNA expression was determined by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). For statistical analysis, t-test, chi-square test, Kruskal-Wallis test and Mann-Whitney U test were performed using SPSS package program and p <0.05 was considered as statistically significant.RESULTS: As a result, the comparison of ApoE gene expression in multiple sclerosis patients and healthy people using real-time PCR technique did not show any statistical significance between the groups (p=0.95).CONCLUSIONS: Our study does not support that ApoE gene expression may be related to MS. Further studies are needed to determine the role of ApoE in Multiple Sclerosis disease.

Scutellaria barbata Flavonoids Improve the Composited Aβ-induced Abnormal Changes in Glial Cells of the Brains of Rats.

It has been reported that glial cells are involved in Alzheimer's disease (AD). In our previous research, Scutellaria barbata flavonoids (SBFs) were found to protect the AD-like rats from neuronal disorder and memory impairment; however, the effect of SBFs on the glial cells disorder in AD-like rats has been less studied. The effects of SBFs on astrocytes (ASs), microglial cells (MGs), and oligodendrocytes (Ols), as well as heat shock protein 70 (Hsp70) and apolipoprotein E (ApoE), were investigated in the present study. The successful model rats, screened by Morris water maze, were orally administrated daily with 35, 70, and 140 mg/kg SBFs for 36 d. The number of brain astrocytes (ASs), microglial cells (MGs), and oligodendrocytes (Ols) was examined by immunohistochemistry. The expressions of cortical glial fibrillary acidic protein (GFAP), leukocyte common antigen (LCA) (CD45), Claudin 11, and heat shock protein 70 (Hsp70) protein were assayed by Western blotting, and the expression of apolipoprotein E (ApoE) mRNA was analyzed by real-time quantitative polymerase chain reaction (qPCR). Compared with the sham-operated group, the number of ASs and MGs in the brain was significantly increased in the model group (P<0.05, P<0.01), accompanied by an increase in the expressions of GFAP, CD45, Hsp70 protein, and ApoE mRNA (P<0.05, P<0.01). Both Ols number and the expression of Claudin 11 protein decreased in the brain in the model group (P<0.05, P<0.01). However, the above-mentioned abnormal changes induced by composited Aβ were differently reversed by the treatment of SBFs at three doses of 35, 70, and 140 mg/kg (P<0.05, P<0.01). SBFs can dramatically improve the abnormal changes in glial cells of the brains of rats, induced by composited Aβ, which may be utilized as a helpful treatment for neurodegenerative diseases.

Desmodium gyrans dc modulates lipid trafficking in cultured macrophages and improves functional high-density lipoprotein in male wistar rats.

OBJECTIVE:High-density lipoprotein (HDL) cholesterol-mediated atherosclerotic plaque regression has gained wide therapeutic attention. The whole plant methanolic extract of the medicinal plant Desmodium gyrans Methanolic Extract (DGM) has shown to mitigate hyperlipidemia in high fat- and-cholesterol fed rats and rabbits with significant HDL enhancing property. The study aimed to assess the functionality and mechanistic basis of HDL promoting effect of DGM.MATERIALS AND METHODS:Macrophage cholesterol efflux and foam cell formation assays were performed in THP-1 macrophages. Male Wistar rats were given DGM extract over 1 month and assessed the serum HDL, Apolipoprotein A1 (Apo-A1), and paraoxonase activity. Quantitative Polymerase chain reaction was carried out to assess the expression level of Apo-A1, SR-B1 (Scavenger receptor B1), and Cholesteryl ester transfer protein (CETP) on cDNA of HepG2 cells exposed to DGM.RESULTS:Pretreatment of DGM inhibited uptake of oxidized lipids and enhanced the lipid efflux by THP-1-derived macrophages. Oral administration of DGM (100 and 250 mg/kg) progressively enhanced the serum HDL, Apo-A1 level, and associated paraoxonase activity in normal male Wistar rats. In support to this, DGM exposed HepG2 cells documented dose-dependent increase in the expression of SR-B1 and Apo-A1 mRNA, while reduced the CETP expression.CONCLUSION:Overall the results indicated that DGM modulates lipid trafficking and possesses functional HDL enhancing potential through increased Apo-A1 levels and paraoxonase activity. Further, reduced CETP expression and increased expression of SR-B1 suggest the reverse cholesterol transport promoting role of DGM.

Neuroprotective Effects of the FGF21 Analogue LY2405319.

To date, there are no effective treatments for Alzheimer's disease (AD). Thus, a significant need for research of therapies remains. One promising pharmacological target is the hormone fibroblast growth factor 21 (FGF21), which is thought to be neuroprotective. A clinical candidate for medical use could be the FGF21 analogue LY2405319 (LY), which has a specificity and potency comparable to FGF21. The present study investigated the potential neuroprotective effect of LY via PPARγ/apoE/abca1 pathway, which is known to degrade amyloid-β (Aβ) plaques by using primary glial cells and hippocampal organotypic brain slice cultures (OBSCs) from 30- and 50-week-old transgenic APPswe/PS1dE9 (tg) mice. By LY treatment of 52-week-old tg mice with advanced Aβ deposition, we further aimed to elaborate the effect of LY on AD pathology in vivo. LY application to primary glial cells caused an upregulation of pparγ, apoE, and abca1 mRNA expression and significantly decreased number and area of Aβ plaques in OBSCs. LY treatment in tg mice increased cerebral [18F] FDG uptake and N-acetylaspartate/creatine ratio indicating enhanced neuronal activity and integrity. Although LY did not reduce the number of Aβ plaques in tg mice, the number of iba1-positive cells was significantly decreased indicating reduced microgliosis. These data identified LY in vitro as an activator of Aβ degrading genes leading to cerebral Aβ load amelioration in early and late AD pathology. Although Aβ plaque reduction by LY failed in vivo, LY may be used as therapeutic agent to treat AD-related neuroinflammation and impaired neuronal integrity.

Влияние адипонектина на продукцию аполипопротеинов А-1 и Е макрофагами человека

Adiponectin is an adipose tissue hormone affecting energy and lipoprotein metabolism and modulating inflammatory responses. However, the role of this adipokine in atherogenesis remains poorly understood. The aim of this study was to investigate the effect of adiponectin on the production of apolipoproteins (apo) A-l and E by human macrophages (MP). The study was conducted on macrophage-like cells of the THP-1 cell line of two differentiation terms, 3 and 5 days (3d and 5d). Adiponectin (10 μg/mL) stimulated the expression of apoA-1 gene at the mRNA level in 5d MP, but not in 3d MP. The level of apoE mRNA in MP under the action of adiponectin was not affected. Adiponectin suppressed macrophage TNF gene expression, while it induced the expression of IL-10 gene in 5d MP. The secreted levels of apoA-1 and apoE proteins under the action of adiponectin in macrophages of both periods of differentiation remained unchanged, while the level of the surface apoA-1 protein in 5d MP was decreasing. Incubation of 5d MP with the PPARα nuclear receptor antagonist MK-886 or with the nuclear receptor LXR agonist TO-901317 resulted in cancellation of the stimulating effect of adiponectin on apoA-1 gene expression. These data indicate that adiponectin, in addition to its anti-inflammatory action, has a modulating effect on production of apoA-1 by macrophages. The latter is probably one of the mechanisms of the influence of this adipokine on atherogenesis.

Reactive or transgenic increase in microglial TYROBP reveals a TREM2-independent TYROBP-APOE link in wild-type and Alzheimer's-related mice.

IntroductionMicroglial TYROBP (DAP12) is a network hub and driver in sporadic late‐onset Alzheimer's disease (AD). TYROBP is a cytoplasmic adaptor for TREM2 and other receptors, but little is known about its roles and actions in AD. Herein, we demonstrate that endogenous Tyrobp transcription is specifically increased in recruited microglia.MethodsUsing a novel transgenic mouse overexpressing TYROBP in microglia, we observed a decrease of the amyloid burden and an increase of TAU phosphorylation stoichiometry when crossed with APP/PSEN1 or MAPTP301S mice, respectively. Characterization of these mice revealed Tyrobp‐related modulation of apolipoprotein E (Apoe) transcription. We also showed that Tyrobp and Apoe mRNAs were increased in Trem2‐null microglia recruited around either amyloid beta deposits or a cortical stab injury. Conversely, microglial Apoe transcription was dramatically diminished when Tyrobp was absent.ConclusionsOur results provide evidence that TYROBP‐APOE signaling does not require TREM2 and could be an initiating step in establishment of the disease‐associated microglia (DAM) phenotype.

PSVII-12 Investigating the influence of copper supplementation on copper homeostatic genes in bovine liver

Abstract The objective of this experiment was to investigate the influence of copper (Cu) supplementation on Cu homeostatic genes in bovine liver. Liver samples were obtained from multiparous cows (n = 3 cows per treatment) from a previous experiment. Treatments consisted of: 1) no supplemental Cu (-Cu; total diet contained 7.0 mg Cu/kg DM) and 2) 3 mg Cu/kg DM (+Cu; total diet contained 10.0 mg Cu/kg DM). Cows were fed their respective diets for 420 d. Liver samples were harvested immediately upon slaughter, rinsed with phosphate-buffered saline solution, diced into small pieces, and placed into RNAlater and frozen at -80°C. Total RNA was extracted from all samples, and quantitative RT-PCR was used to determine the abundance of transcripts for proteins involved in Cu homeostasis in liver tissue. The target transcripts were: ALDH2, APOA1, ATOX1, ATP7A, ATP7B, BHMT, BLVRB, CA2, CCS, COX17, CTR1, ELN, GAPDH, GLUD1, GSS, LOXL1, PDIA3, SOD1, SOD3. The relative abundance of APOA1, ATOX1, ATP7B, BLVRB, CTR1, GLUD1, LOXL1, and SOD3 mRNA was greater (P &amp;lt; 0.05) in cows receiving supplemental Cu when compared to cattle not receiving supplemental Cu. These data indicate possible differences in Cu homeostasis in the liver based on Cu supplementation. Further investigation is warranted to determine if a difference in the relative abundance of identified transcripts are related to differences in associated protein production and function.

Identifying Blood Transcriptome Biomarkers of Alzheimer\u2019s Disease Using Transgenic Mice

The testing of pathological biomarkers of Alzheimer’s disease (AD), such as amyloid beta and tau, is time-consuming, expensive, and invasive. Here, we used 3xTg-AD mice to identify and validate putative novel blood transcriptome biomarkers of AD that can potentially be identified in the blood of patients. mRNA was extracted from the blood and hippocampus of 3xTg-AD and control mice at different ages and used for microarray analysis. Network and functional analyses revealed that the differentially expressed genes between AD and control mice modulated the immune and neuroinflammation systems. Five novel gene transcripts (Cdkn2a, Apobec3, Magi2, Parp3, and Cass4) showed significant increases with age, and their expression in the blood was collated with that in the hippocampus only in AD mice. We further assessed previously identified candidate biomarker genes. The expression of Trem1 and Trem2 in both the blood and brain was significantly increased with age. Decreased Tomm40 and increased Pink1 mRNA levels were observed in the mouse blood. The changes in the expression of Snca and Apoe mRNA in the mouse blood and brain were similar to those found in human AD blood. Our results demonstrated that the immune and neuroinflammatory system is involved in the pathophysiologies of aging and AD and that the blood transcriptome might be useful as a biomarker of AD.

Trem2 deficiency differentially affects phenotype and transcriptome of human APOE3 and APOE4 mice

BackgroundAlzheimer’s Disease (AD) is a neurodegenerative disorder influenced by aging and genetic risk factors. The inheritance of APOEε4 and variants of Triggering Receptor Expressed on Myeloid cells 2 (TREM2) are major genetic risk factors for AD. Recent studies showed that APOE binds to TREM2, thus raising the possibility of an APOE-TREM2 interaction that can modulate AD pathology.MethodsThe aim of this study was to investigate this interaction using complex AD model mice - a crossbreed of Trem2ko and APP/PSEN1dE9 mice expressing human APOE3 or APOE4 isoforms (APP/E3 and APP/E4 respectively), and their WT littermates (E3 and E4), and evaluate cognition, steady-state amyloid load, plaque compaction, plaque growth rate, glial response, and brain transcriptome.ResultsIn both, APP/E3 and APP/E4 mice, Trem2 deletion reduced plaque compaction but did not significantly affect steady-state plaque load. Importantly, the lack of TREM2 increased plaque growth that negatively correlated to the diminished microglia barrier, an effect most pronounced at earlier stages of amyloid deposition. We also found that Trem2 deficiency significantly decreased plaque-associated APOE protein in APP/E4 but not in APP/E3 mice in agreement with RNA-seq data. Interestingly, we observed a significant decrease of Apoe mRNA expression in plaque-associated microglia of APP/E4/Trem2ko vs APP/E4 mice. The absence of TREM2, worsened cognitive performance in APP transgenic mice but not their WT littermates.Gene expression analysis identified Trem2 signature - a cluster of highly connected immune response genes, commonly downregulated as a result of Trem2 deletion in all genotypes including APP and WT littermates. Furthermore, we identified sets of genes that were affected in TREM2- and APOE isoform-dependent manner. Among them were Clec7a and Csf1r upregulated in APP/E4 vs APP/E3 mice, a result further validated by in situ hybridization analysis. In contrast, Tyrobp and several genes involved in the C1Q complement cascade had a higher expression level in APP/E3 versus their APP/E4 counterparts.ConclusionsOur data demonstrate that lack of Trem2 differentially impacts the phenotype and brain transcriptome of APP mice expressing human APOE isoforms. The changes probably reflect the different effect of APOE isoforms on amyloid deposition.

Effect of the insulin on the apolipoprotein a-i gene expression in human macrophages

The aim of the article to study the effect of insulin on apolipoprotein A-I gene expression level in human macrophages and to reveal the main signal cascades which take part in the insulin-mediated regulation of apolipoprotein A-I gene.&#x0D; Materials and methods. The experiments were carried out on the macrophages differentiated from acute monocytic leukemia cell line THP-1 and on the macrophages differentiated from the monocytes isolated from peripheral human blood. The analysis of apoA-I gene expression was performed by RealTime RT-PCR (on the mRNA level) and by flow cytofluorometry. To study the signalling cascades which take part in the insulin-mediated regulation of apoA-I gene the inhibitory analysis was used.&#x0D; Results. Insulin induces the human apoA-I gene transcription in macrophages, but decreases the level of the ApoA-I protein which binds to outer cytoplasmic membrane of macrophages. The insulin-mediated transcription of apoA-I gene depends on PI3K-AKT signal cascade and transcription factors NF-B and LXRs.&#x0D; Conclusions. Taking into account our previous data it is plausible to conclude that the elevation of ApoA-I mRNA in human macrophages after insulin treatment leads to an increase of the amplitude of macrophages anti-inflammatory response, which consists in a sharp rise in the level of surface ApoA-I in macrophages under the some proinflammatory stimuli (TNF, LPS).

Protective effects of Coenzyme Q10 against sevoflurane-induced cognitive impairment through regulating apolipoprotein E and phosphorylated Tau expression in young mice.

Children with multiple exposures to anesthesia and surgery may be more likely to develop the learning disability. Coenzyme Q10 (CoQ10) was reported to reduce the multiple sevoflurane treatment-induced cognitive deficiency in 6-day-old young mice. However, its specific mechanisms have not yet been found. This research aimed to reveal the role of ApoE in the pathogenesis of cognitive deficiency caused by sevoflurane anesthesia and the protective mechanism of CoQ10 in a multiple sevoflurane treatment model of young mice. The mice were randomly divided into four groups: Control+corn oil, Sevoflurane+corn oil, Control+CoQ10, and Sevoflurane+CoQ10. Sevoflurane group mice were anesthetized with 3% sevoflurane and 60% oxygen 2hr a day for 3days, while control group mice received only 60% oxygen. Mice received an intraperitoneal injection of 50mg/kg CoQ10 or the same volume of corn oil 30min before the inhalation of oxygen or sevoflurane for 3days. Mice received sevoflurane anesthesia or control treatment from the 6th to 8th day after birth. The cortex and hippocampus were harvested on the 8th day. The ATP, MMP, ApoE mRNA, total ApoE, ApoE fragments, Aβ1-40, Aβ1-42, Tau5, AT8, and PHF levels were detected. The Morris water maze (MWM) tests were performed from P30 to p36 after anesthesia or control treatment. The results indicated that the injection of CoQ10 ahead of sevoflurane treatment could reverse the anesthesia-induced energy deficiency, mitochondrial dysfunction, ApoE, and its fragments expression, Aβ1-42 generation, Tau phosphorylation, and cognitive impairment in young mice. These data reveal that the ApoE and its fragments enhancement may play an important role in the pathogenesis of cognitive deficiency caused by sevoflurane anesthesia. CoQ10 could reduce ApoE expression by improving energy replenishment and mitochondrial functions, thereby alleviating sevoflurane-induced brain damage and cognitive impairment.

Cell Type Impacts Accessibility of mRNA to Silencing by RNA Interference

RNA interference (RNAi) is a potent mechanism that silences mRNA and protein expression in all cells and tissue types. RNAi is known to exert many of its functional effects in the cytoplasm, and thus, the cellular localization of target mRNA may impact observed potency. Here, we demonstrate that cell identity has a profound impact on accessibility of apolipoprotein E (ApoE) mRNA to RNAi. We show that, whereas both neuronal and glial cell lines express detectable ApoE mRNA, in neuronal cells, ApoE mRNA is not targetable by RNAi. Screening of a panel of thirty-five chemically modified small interfering RNAs (siRNAs) did not produce a single hit in a neuronal cell line, whereas up to fifteen compounds showed strong efficacy in glial cells. Further investigation of the cellular localization of ApoE mRNA demonstrates that ApoE mRNA is partially spliced and preferentially localized to the nucleus (∼80%) in neuronal cells, whereas more than 90% of ApoE mRNA is cytoplasmic in glial cells. Such an inconsistency in intracellular localization and splicing might provide an explanation for functional differences in RNAi compounds. Thus, cellular origin might have an impact on accessibility of mRNA to RNAi and should be taken into account during the screening process.

Coenzyme Q10 alleviates sevoflurane‑induced neuroinflammation by regulating the levels of apolipoprotein E and phosphorylated tau protein in mouse hippocampal neurons.

Sevoflurane may exert neurotoxic effects on the developing brain. Coenzyme Q10 (CoQ10) has been reported to reduce sevoflurane anesthesia-induced cognitive deficiency in 6-day-old mice. However, its specific mechanisms remain unknown. Apolipoprotein E (ApoE) has been reported to lead to the initiation of neurodegeneration in patients with Alzheimer's disease (AD) and may serve an important role in anesthesia-induced neurotoxicity. The present study aimed to reveal the role of ApoE in the pathogenesis of tau protein hyperphosphorylation and neuroinflammation enhancement caused by sevoflurane anesthesia, as well as the protective mechanism of CoQ10 in an anesthetic sevoflurane treatment model of primary mouse hippocampal neurons. For that purpose, the neurons were randomly assigned to the following groups: i) Control; ii) sevoflurane; iii) control+corn oil; iv) sevoflurane+corn oil; v) control+CoQ10; and vi) control+CoQ10. CoQ10 or corn oil alone was added to the medium on day 4 of neuron culture. The neurons in the sevoflurane group were treated with 21% O2, 5% CO2 and 4.1% sevoflurane for 4 h, whereas the control group only with 21% O2 and 5% CO2 on day 5. Samples were collected immediately after anesthesia or control treatment. ATP, superoxidase dismutase (SOD)1, ApoE mRNA, total ApoE, full-length ApoE, ApoE fragments, Tau5, Tau-PS202/PT205 (AT8), Tau-PSer396/404 (PHF1), tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β levels were measured with ELISA, quantitative PCR, western blotting and immunocytochemistry. The results of the present study indicated that sevoflurane anesthesia significantly decreased the ATP and SOD levels, but increased ApoE mRNA, total ApoE protein, full-length ApoE, ApoE fragments, phosphorylated tau (AT8 and PHF1) and neuroinflammatory factor (TNF-α, IL-6 and IL-1β) expression levels compared with those in the control group. The use of CoQ10 reversed the expression of these factors. These results suggested that sevoflurane treatment damaged mouse hippocampal neurons, which may be associated with the expression of ApoE and its toxic fragments. CoQ10 improved energy replenishment and inhibited oxidative stress, which may lead to a decrease in ApoE and phosphorylated tau protein expression, thus mitigating the sevoflurane-induced neuroinflammation in mouse hippocampal neurons.

Assessment of Novel Rexinoids for Therapeutic Potential in Combating Alzheimer's Disease

Bexarotene is an FDA approved anti‐cancer agent, but more recently this drug has been assessed for its potential as a therapeutic for dementia. Bexarotene may reduce amyloid beta (α□) plaques that are thought to play a role in Alzheimer’s disease pathophysiology, although clinical use of bexarotene causes unwanted side‐effects including hyperlipidemia and hypothyroidism. Bexarotene drives retinoid‐X‐receptor (RXR) homodimerization on the retinoid‐X‐response element (RXRE), as well as facilitating heterodimers with liver‐X‐receptors (LXR) and peroxisome proliferator activated receptor gamma (PPARγ). These RXR‐containing dimers are hypothesized to induce apolipoprotein (ApoE) in glial cells to control lipid and cholesterol homeostasis in the brain. We tested the ability of bexarotene and a panel of novel rexinoids to drive RXR dimerization using dual luciferase reporter assays to assess transcriptional efficiency of these compounds. We employed both RXRE‐mediated reporter assays, as well as a mammalian 2 hybrid system (M2H) to probe the ability of our novel rexinoids to activate RXR signaling. These compounds were also tested as activators of LXRE‐directed transcription, and as inducers of ApoE mRNA in U87 glial cells. Results from these multiple assay systems reveal that our panel of RXR analogs contain compounds with diverse activities, some of which bind to RXR with greater affinity than others, and in some cases can stimulate ApoE expression to a greater extent than bexarotene. These results suggest that chemical modifications to the parent bexarotene chemical scaffold may yield novel analogs with an amplified ability to activate RXR and possibly combat Alzheimer’s disease via a reduction in amyloid beta (α□) plaques.Support or Funding InformationCoins For Alzheimer’s Research Trust

Amoxicillin Modulates ApoA-I Transcription and Secretion, Predominantly via PPARα Transactivation Inhibition.

In a recent human study, we observed that amoxicillin treatment decreased HDL-C concentration. We hypothesize that antibiotics lower the transcription and secretion of ApoA-I, the responsible protein for HDL production. HepG2 and Caco-2 cells were exposed to increasing dose of amoxicillin, penicillin, and streptomycin. Secreted ApoA-I protein and mRNA transcripts were analyzed using ELISA and qPCR, respectively. To unravel underlying mechanisms, KEAP1, CPT1, and CHOP mRNA expressions were determined as well as PPARα transactivation. In HepG2 and Caco-2, amoxicillin decreased ApoA-I transcription and secretion. Effects on ApoA-I expression were clearly there for amoxicillin while no effects were observed for penicillin or streptomycin. KEAP1, CPT1, and CHOP mRNA expressions were reduced by amoxicillin treatments. Moreover, a significant correlation between ApoA-I and CPT1 mRNA expressions was found. Furthermore, amoxicillin lowered PPARα transactivation. All together, these data suggest that inhibited PPARα transactivation is involved in the effects of amoxicillin on ApoA-I. In conclusion, the direct effect of amoxicillin in treated HepG2 and Caco-2 cells was a lower ApoA-I secretion and transcription. Based on evaluating alterations in KEAP1, CPT1, and CHOP mRNA expressions plus PPARα transactivation, we suggest that a reduced PPARα activation is a potential mechanism behind the observed amoxicillin effects on ApoA-I expression.

LCAT, ApoD, and ApoA1 Expression and Review of Cholesterol Deposition in the Cornea.

Lecithin:cholesterol acyltransferase (LCAT) is an enzyme secreted by the liver and circulates with high-density lipoprotein (HDL) in the blood. The enzyme esterifies plasma cholesterol and increases the capacity of HDL to carry and potentially remove cholesterol from tissues. Cholesterol accumulates within the extracellular connective tissue matrix of the cornea stroma in individuals with genetic deficiency of LCAT. LCAT can be activated by apolipoproteins (Apo) including ApoD and ApoA1. ApoA1 also mediates cellular synthesis of HDL. This study examined the expression of LCAT by epithelial cells, keratocytes, and endothelial cells, the cell types that comprise from anterior to posterior the three layers of the cornea. LCAT and ApoD were immunolocalized to all three cell types within the cornea, while ApoA1 was immunolocalized to keratocytes and endothelium but not epithelium. In situ hybridization was used to detect LCAT, ApoD, and ApoA1 mRNA to learn what cell types within the cornea synthesize these proteins. No corneal cells showed mRNA for ApoA1. Keratocytes and endothelium both showed ApoD mRNA, but epithelium did not. Epithelium and endothelium both showed LCAT mRNA, but despite the presence of LCAT protein in keratocytes, keratocytes did not show LCAT mRNA. RNA sequencing analysis of serum-cultured dedifferentiated keratocytes (commonly referred to as corneal stromal fibroblasts) revealed the presence of both LCAT and ApoD (but not ApoA1) mRNA, which was accompanied by their respective proteins detected by immunolabeling of the cultured keratocytes and Western blot analysis of keratocyte lysates. The results indicate that keratocytes in vivo show both ApoA1 and LCAT proteins, but do not synthesize these proteins. Rather, keratocytes in vivo must take up ApoA1 and LCAT from the corneal interstitial tissue fluid.

SRSF11 Loss Leads to Aging-Associated Cognitive Decline by Modulating LRP8 and ApoE

RNA binding proteins, the key regulators in gene expression at the posttranscriptional level, remain largely uncharacterized with respect to aging and relevant cognitive deterioration. Here, we report that the levels of SFRS11 are substantially decreased in the prefrontal cortex (PFC) of aged brains. Notably, mice with SFRS11 deficiency in the PFC show impaired learning and memory. We demonstrate that SFRS11 directly binds to the 3' UTR of LRP8 mRNA, as well as to the third exon of apoE mRNA, resulting in stabilization of these mRNAs, eventually deactivating JNK signaling. Importantly, restoration of LRP8 and apoE reduces JNK signaling that is significantly enhanced in SFRS11-deficient cells. In addition, LRP8 and apoE rescue aging-like phenotypes induced by SFRS11 loss. Our findings demonstrate that age-dependent loss of SFRS11 in the PFC reduces levels of apoE and LRP8, leading to activation of the JNK pathway, ultimately influencing cognitive deficits.

Lipid-lowering effect of Phyllanthus embilica and Alpinia galanga extracts on HepG2 cell line

Dyslipidemia is a key risk factor for cardiovascular diseases. Although statins are powerful therapeutic option for achieving target low- and high-density lipoprotein levels, it is of interest to seek for alternative treatments for dyslipidemia. Phyllanthus emblica and Alpinia galanga were found to have hypolipidemic effects. However, the mechanisms underlying their bioactivity have not yet been elucidated. Lipid-lowering effects of the hydroethanolic extracts from a Phyllanthus emblica (PE), Alpinia galangal (AG) and a combination between P. emblica and A. galangal (PEAG; ratio 7:3 w/w) on expression of low-density lipoprotein receptor (LDLR), 3-hydroxyl-3-methylglutaryl-CoA reductase (HMGCR), apolipoprotein A1 (ApoA1) and scavenger receptor class B1 (SR-BI) genes were assessed in HepG2 cell line using quantitative RT-PCR (qRT-PCR). It was demonstrated from the MTT cytotoxic assay that PE and PEAG were not cytotoxic to HepG2 cell line. AG, gallic acid and simvastatin were more cytotoxic to HepG2 cell line. PEAG was found to be the most promising therapeutic agent for clearance of circulating LDL-C due to its enhancing expression of the LDLR gene. It could contribute towards enhancement of the HDL-C levels due to its upregulation expression of the APOA1 and SR-B1 mRNA transcripts in HepG2 cells.

The effects of short-chain fatty acids on the transcription and secretion of apolipoprotein A-I in human hepatocytes in vitro.

BackgroundApolipoprotein‐I (ApoA‐I), the major component of high‐density lipoprotein (HDL) particles, mediates cholesterol efflux by which it facilitates the removal of excess cholesterol from peripheral tissues. Therefore, elevating ApoA‐I production leading to the production of new pre‐β‐HDL particles is thought to be beneficial in the prevention of cardiovascular diseases. Recently, we observed that amoxicillin treatment led to decreased HDL concentrations in healthy human volunteers. We questioned whether this antibiotic effect was directly or indirectly, via changed short‐chain fatty acids (SCFA) concentrations through an altered gut microflora. Therefore, we here evaluated the effects of amoxicillin and various SCFA on hepatic ApoA‐I expression, secretion, and the putative underlying pathways.Methods and ResultsHuman hepatocytes (HepG2) were exposed to increasing dose of amoxicillin or SCFA for 48 hours. ApoA‐I messenger RNA (mRNA) transcription and secreted protein were analyzed using quantitative polymerase chain reaction and enzyme‐linked immunosorbent assay, respectively. To study underlying mechanisms, changes in mRNA expression of KEAP1, CPT1, and PPARα, as well as a PPARα transactivation assay, were analyzed. Amoxicillin dose‐dependently decreased ApoA‐I mRNA transcription as well as ApoA‐I protein secretion. SCFA treatment resulted in a dose‐dependent stimulation of ApoA‐I mRNA transcription, however, the ApoA‐I protein secretion was decreased. Furthermore, SCFA treatment increased PPARα transactivation, PPARα and CPT1 mRNA transcription, whereas KEAP1 mRNA transcription was decreased.ConclusionDirect treatment of HepG2 cells with amoxicillin has either direct effects on lowering ApoA‐I transcription and secretion or indirect effects via modified SCFA concentrations because SCFA were found to stimulate hepatic ApoA‐I expression. Furthermore, BET inhibition and PPARα activation were identified as possible mechanisms behind the observed effects on ApoA‐I transcription.

The effects of aerobic training before and after the induction of Alzheimer's disease on ABCA1 and APOE mRNA expression and the level of soluble Aβ1-42 in the hippocampus of male Wistar rats.

Objective(s):The purpose of this study was to investigate the effects of aerobic training before and after the induction of Alzheimer’s disease on ABCA1 and APOE mRNA expression and the level of soluble Aβ1-42 in the hippocampus of male Wistar rats.Materials and Methods:Ninety six eight-week-old male Wistar rats were randomly divided into two groups: Training (n=48) and Rest (n=48). After four weeks, each group was randomly divided into two subgroups: intra-hippocampal injection of Aβ1-42 (n=24) and DMSO (n=24). Then, each group was again randomly divided into two groups: Training (n=12) and Rest (n=12). After four weeks, each group was again randomly divided into two groups: Behavioral test (n=7) and sacrificed (n=5). Results:The one-way ANOVA showed a significant increase in the mRNA expression of ABCA1 (P<0.05), a significant decrease in the level of soluble Aβ1-42, and no significant difference in the expression of APOE mRNA (P>0.05) in the hippocampus as a result of training. The analysis of the Morris water maze data showed that intra-hippocampal injection of Aβ1-42 impaired spatial learning and memory and exercise improved spatial learning (P<0.05) and memory (P<0.05).Conclusion:Therefore, aerobic training by a significant increase in the mRNA expression of ABCA1, which is the main factors of lipid metabolism in the brain and which is involved in the pathology of Alzheimer’s disease, can be consistent with improving cognitive function as an effective way of preventing and improving the symptoms of Alzheimer’s disease.