Differential effects of simvastatin and pravastatin on expression of Alzheimer's disease-related genes in human astrocytes and neuronal cells

Rosuvastatin attenuates total-tau serum levels and increases expression of miR-124-3p in dyslipidemic Alzheimer's patients: a historic cohort study

microRNAs are candidate diagnostic biomarkers for Alzheimer's disease. This study aimed to compare Silymarin with Rosuvastatin and placebo on total-Tau protein level and expression levels of microRNAs and TGF-β and COX-2 in Alzheimer's patients with secondary dyslipidemia. 36 mild AD patients with dyslipidemia were divided into three groups of 12. The first group received silymarin (140mg), the second group received placebo (140mg), and the third group recieved Rosuvastatin (10mg). Tablets were administered three times a day for Six months. The blood samples of the patients were collected before and after the intervention and the serum was separated. Using the RT-qPCR method, the expression levels of miR-124-3p and miR-125b-5p were assessed, and the serum levels of total-Tau, TGF-β, and COX-2 enzyme were measured using the ELISA method. Data were analyzed with SPSS software. In this study, the level of Δtotal-Tau was significantly lower in the Rosuvastatin group compared to the placebo (P = 0.038). Also, a significant reduction in the level of ΔTGF-β was observed in the Silymarin to Rosuvastatin group (p = 0.046) and ΔmiR-124-3p was significantly increased in the Rosuvastatin compared to the placebo group (p = 0.044). Rosuvastatin outperformed silymarin in decreasing Δtotal-Tau serum levels and enhancing expression of ΔmiR-124-3p, attributed to Rosuvastatin's capacity to lower cholesterol levels and inflammation concurrently. Conversely, silymarin was more effective than Rosuvastatin in reducing levels of ΔTGF-β. Serum miR-124-3p could serve as a promising diagnostic biomarker and a new therapeutic focus in AD.

Effect of Statin Lipophilicity on the Proliferation of Hepatocellular Carcinoma Cells

The HMG-CoA reductase inhibitors, statins, are drugs used globally for lowering the level of cholesterol in the blood. Different clinical studies of statins in cancer patients have indicated a decrease in cancer mortality, particularly in patients using lipophilic statins compared to those on hydrophilic statins. In this paper, we selected two structurally different statins (simvastatin and pravastatin) with different lipophilicities and investigated their effects on the proliferation and apoptosis of hepatocellular carcinoma cells. Lipophilic simvastatin highly influences cancer cell growth and survival in a time- and concentration-dependent manner, while pravastatin, due to its hydrophilic structure and limited cellular uptake, showed minimal cytotoxic effects.

Role of hydroxymethylglutharyl-coenzyme A reductase in the induction of stem-like states in breast cancer

PURPOSE

De novo synthesis of cholesterol and its rate-limiting enzyme, 3-hydroxy-3-methylglutharyl-coenzyme A reductase (HMGCR), is deregulated in tumors and critical for tumor cell survival and proliferation. However, the role of HMGCR in the induction and maintenance of stem-like states in tumors remains unclear.

METHODS

A compiled public database from breast cancer (BC) patients was analyzed with the web application SurvExpress. Cell Miner was used for the analysis of HMGCR expression and statin sensitivity of the NCI-60 cell lines panel. A CRISPRon system was used to induce HMGCR overexpression in the luminal BC cell line MCF-7 and a lentiviral pLM-OSKM system for the reprogramming of MCF-7 cells. Comparisons were performed by two-tailed unpaired t-test for two groups and one- or two-way ANOVA.

RESULTS

Data from BC patients showed that high expression of several members of the cholesterol synthesis pathway were associated with lower recurrence-free survival, particularly in hormone-receptor-positive BC. In silico and in vitro analysis showed that HMGCR is expressed in several BC cancer cell lines, which exhibit a subtype-dependent response to statins in silico and in vitro. A stem-like phenotype was demonstrated upon HMGCR expression in MCF-7 cells, characterized by expression of the pluripotency markers NANOG, SOX2, increased CD44 +/CD24low/ -, CD133 + populations, and increased mammosphere formation ability. Pluripotent and cancer stem cell lines showed high expression of HMGCR, whereas cell reprogramming of MCF-7 cells did not increase HMGCR expression.

CONCLUSION

HMGCR induces a stem-like phenotype in BC cells of epithelial nature, thus affecting tumor initiation, progression and statin sensitivity.

Lipophilic Statins Eliminate Senescent Endothelial Cells by inducing Anoikis-Related Cell Death

Pre-clinical studies from the recent past have indicated that senescent cells can negatively affect health and contribute to premature aging. Targeted eradication of these cells has been shown to improve the health of aged experimental animals, leading to a clinical interest in finding compounds that selectively eliminate senescent cells while sparing non-senescent ones. In our study, we identified a senolytic capacity of statins, which are lipid-lowering drugs prescribed to patients at high risk of cardiovascular events. Using two different models of senescence in human vascular endothelial cells (HUVECs), we found that statins preferentially eliminated senescent cells, while leaving non-senescent cells unharmed. We observed that the senolytic effect of statins could be negated with the co-administration of mevalonic acid and that statins induced cell detachment leading to anoikis-like apoptosis, as evidenced by real-time visualization of caspase-3/7 activation. Our findings suggest that statins possess a senolytic property, possibly also contributing to their described beneficial cardiovascular effects. Further studies are needed to explore the potential of short-term, high-dose statin treatment as a candidate senolytic therapy.

Importance of Mevalonate Pathway Lipids on the Growth and Survival of Primary and Metastatic Gastric Carcinoma Cells

Purpose

This preclinical study aims to determine the effect of drugs that alter isoprenoids and cholesterol metabolism in the homeostasis of gastric carcinoma cell lines in the search for new therapeutic targets for stomach cancer.

Materials and Methods

Primary (AGS) and metastatic (NCI-N87) gastric cancer cell lines were treated with simvastatin and terbinafine, two inhibitors of the mevalonate pathway, and avasimibe, an inhibitor of cholesterol esterification. Cell viability and growth were measured as well as cholesterol levels and the expression of the hydroxy methyl-glutaryl CoA reductase (HMGCR) and the LDL receptor (LDLR).

Results

Primary and metastatic gastric carcinoma cells show different sensitivity to drugs that affect isoprenoid synthesis and the metabolism and uptake of cholesterol. Isoprenoids are involved in the growth and viability of both types of cells, but the role of free and esterified cholesterol for metastatic gastric cell survival is not as evident as for primary gastric cancer cells. Differential expression of LDLR due to mevalonate pathway inhibition suggests variations in the regulation of cholesterol uptake between primary and metastatic cancer cells.

Conclusion

These results indicate that at least for primary gastric cancer, statins and avasimibe are promising candidates as potential novel antitumor drugs that target the metabolism of isoprenoids and cholesterol of gastric tumors.

Endothelial Klf2-Foxp1-TGFβ signal mediates the inhibitory effects of simvastatin on maladaptive cardiac remodeling

Aims: Pathological cardiac fibrosis and hypertrophy are common features of left ventricular remodeling that often progress to heart failure (HF). Endothelial cells (ECs) are the most abundant non-myocyte cells in adult mouse heart. Simvastatin, a strong inducer of Krüppel-like Factor 2 (Klf2) in ECs, ameliorates pressure overload induced maladaptive cardiac remodeling and dysfunction. This study aims to explore the detailed molecular mechanisms of the anti-remodeling effects of simvastatin.

Methods and Results: RGD-magnetic-nanoparticles were used to endothelial specific delivery of siRNA and we found absence of simvastatin's protective effect on pressure overload induced maladaptive cardiac remodeling and dysfunction after in vivo inhibition of EC-Klf2. Mechanism studies showed that EC-Klf2 inhibition reversed the simvastatin-mediated reduction of fibroblast proliferation and myofibroblast formation, as well as cardiomyocyte size and cardiac hypertrophic genes, which suggested that EC-Klf2 might mediate the anti-fibrotic and anti-hypertrophy effects of simvastatin. Similar effects were observed after Klf2 inhibition in cultured ECs. Moreover, Klf2 regulated its direct target gene TGFβ1 in ECs and mediated the protective effects of simvastatin, and inhibition of EC-Klf2 increased the expression of EC-TGFβ1 leading to simvastatin losing its protective effects. Also, EC-Klf2 was found to regulate EC-Foxp1 and loss of EC-Foxp1 attenuated the protective effects of simvastatin similar to EC-Klf2 inhibition.

Conclusions: We conclude that cardiac microvasculature ECs are important in the modulation of pressure overload induced maladaptive cardiac remodeling and dysfunction, and the endothelial Klf2-TGFβ1 or Klf2-Foxp1-TGFβ1 pathway mediates the preventive effects of simvastatin. This study demonstrates a novel mechanism of the non-cholesterol lowering effects of simvastatin for HF prevention.

Simvastatin profoundly impairs energy metabolism in primary human muscle cells

OBJECTIVES

Simvastatin use is associated with muscular side effects, and increased risk for type 2 diabetes (T2D). In clinical use, simvastatin is administered in inactive lipophilic lactone-form, which is then converted to active acid-form in the body. Here, we have investigated if lactone- and acid-form simvastatin differentially affect glucose metabolism and mitochondrial respiration in primary human skeletal muscle cells.

METHODS

Muscle cells were exposed separately to lactone- and acid-form simvastatin for 48 h. After pre-exposure, glucose uptake and glycogen synthesis were measured using radioactive tracers; insulin signalling was detected with Western blotting; and glycolysis, mitochondrial oxygen consumption and ATP production were measured with Seahorse XFe96 analyzer.

RESULTS

Lactone-form simvastatin increased glucose uptake and glycogen synthesis, whereas acid-form simvastatin did not affect glucose uptake and decreased glycogen synthesis. Phosphorylation of insulin signalling targets Akt substrate 160 kDa (AS160) and glycogen synthase kinase 3β (GSK3β) was upregulated with lactone-, but not with acid-form simvastatin. Exposure to both forms of simvastatin led to a decrease in glycolysis and glycolytic capacity, as well as to a decrease in mitochondrial respiration and ATP production.

CONCLUSIONS

These data suggest that lactone- and acid-forms of simvastatin exhibit differential effects on non-oxidative glucose metabolism as lactone-form increases and acid-form impairs glucose storage into glycogen, suggesting impaired insulin sensitivity in response to acid-form simvastatin. Both forms profoundly impair oxidative glucose metabolism and energy production in human skeletal muscle cells. These effects may contribute to muscular side effects and risk for T2D observed with simvastatin use.

Mevalonate pathway as a novel target for the treatment of metastatic gastric cancer

Gastric mucosa tumors may present as two distinct major entities: Diffuse and intestinal subtypes. There is no standard treatment for advanced or metastatic gastric cancer. The mevalonate pathway and cholesterol homeostasis are important processes in cancer cells that may be highly relevant in terms of cell growth, survival and metastatic potential. Two model cell lines representing intestinal (NCI-N87) and diffuse (Hs746T) metastatic gastric tumor histological subtypes were treated with different drugs that alter membrane lipid metabolism to determine whether cell proliferation, viability and migration were affected. The results indicated that the cells exhibited significant differences in proliferation when treated with the cholesterol-lowering drug simvastatin, but not with terbinafine, another compound that affects cholesterol synthesis. Only simvastatin affected migration in both cell lines. Reposition studies with mevalonolactone, farnesyl pyrophosphate and geranylgeranyl pyrophosphate in the presence of high and low FBS concentrations indicated that both isoprenoids and cholesterol reversed the antiproliferative effects of simvastatin in gastric cancer cells. The cell lines used in the present study had different sensitivities to several potential anti-neoplastic agents that affect the synthesis of membrane lipids. The diffuse gastric cancer cells were particularly sensitive to simvastatin, suggesting it as an option for combination treatment.

Pleiotropic effects of statins on brain cells

Starting with cholesterol homeostasis, the first part of the review addresses various aspects of cholesterol metabolism in neuronal and glial cells and the mutual crosstalk between the two cell types, particularly the transport of cholesterol from its site of synthesis to its target loci in neuronal cells, discussing the multiple mechanistic aspects and transporter systems involved. Statins are next analyzed from the point of view of their chemical structure and its impingement on their pharmacological properties and permeability through cell membranes and the blood-brain barrier in particular. The following section then discusses the transcriptional effects of statins and the changes they induce in brain cell genes associated with a variety of processes, including cell growth, signaling and trafficking, uptake and synthesis of cholesterol. We review the effects of statins at the cellular level, analyzing their impact on the cholesterol composition of the nerve and glial cell plasmalemma, neurotransmitter receptor mobilization, myelination, dendritic arborization of neurons, synaptic vesicle release, and cell viability. Finally, the role of statins in disease is exemplified by Alzheimer and Parkinson diseases and some forms of epilepsy, both in animal models and in the human form of these pathologies.

Statin Drugs Plus Th1 Cytokines Potentiate Apoptosis and Ras Delocalization in Human Breast Cancer Lines and Combine with Dendritic Cell-Based Immunotherapy to Suppress Tumor Growth in a Mouse Model of HER-2pos Disease

A dendritic cell-based, Type 1 Helper T cell (Th1)-polarizing anti-Human Epidermal Growth Factor Receptor-2 (HER-2) vaccine supplied in the neoadjuvant setting eliminates disease in up to 30% of recipients with HER-2-positive (HER-2^pos) ductal carcinoma in situ (DCIS). We hypothesized that drugs with low toxicity profiles that target signaling pathways critical for oncogenesis may work in conjunction with vaccine-induced immune effector mechanisms to improve efficacy while minimizing side effects. In this study, a panel of four phenotypically diverse human breast cancer lines were exposed in vitro to the combination of Th1 cytokines Interferon-gamma (IFN-γ) and Tumor Necrosis Factor-alpha (TNF-α) and lipophilic statins. This combination was shown to potentiate multiple markers of apoptotic cell death. The combination of statin drugs and Th1 cytokines minimized membrane K-Ras localization while maximizing levels in the cytoplasm, suggesting a possible means by which cytokines and statin drugs might cooperate to maximize cell death. A combined therapy was also tested in vivo through an orthotopic murine model using the neu-transgenic TUBO mammary carcinoma line. We showed that the combination of HER-2 peptide-pulsed dendritic cell (DC)-based immunotherapy and simvastatin, but not single agents, significantly suppressed tumor growth. Consistent with a Th1 cytokine-dependent mechanism, parenterally administered recombinant IFN-γ could substitute for DC-based immunotherapy, likewise inhibiting tumor growth when combined with simvastatin. These studies show that statin drugs can amplify a DC-induced effector mechanism to improve anti-tumor activity.

Statins enhance efficacy of venetoclax in blood cancers

Statins have shown promise as anticancer agents in experimental and epidemiologic research. However, any benefit that they provide is likely context-dependent, for example, applicable only to certain cancers or in combination with specific anticancer drugs. We report that inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) using statins enhances the proapoptotic activity of the B cell lymphoma-2 (BCL2) inhibitor venetoclax (ABT-199) in primary leukemia and lymphoma cells but not in normal human peripheral blood mononuclear cells. By blocking mevalonate production, HMGCR inhibition suppressed protein geranylgeranylation, resulting in up-regulation of proapoptotic protein p53 up-regulated modulator of apoptosis (PUMA). In support of these findings, dynamic BH3 profiling confirmed that statins primed cells for apoptosis. Furthermore, in retrospective analyses of three clinical studies of chronic lymphocytic leukemia, background statin use was associated with enhanced response to venetoclax, as demonstrated by more frequent complete responses. Together, this work provides mechanistic justification and clinical evidence to warrant prospective clinical investigation of this combination in hematologic malignancies.

Overview the effect of statin therapy on dementia risk, cognitive changes and its pathologic change: a systematic review and meta-analysis

Background

Many studies have reported on the role of statin therapy in dementia, but its efficacy remains controversial. We aimed to search for reliable and meaningful articles to assess the efficacy of statin therapy for dementia risk, cognitive items, and pathologic markers.

Methods

Related literature for this study was published in the period from January 1, 1987 to January 1, 2018. Odds ratio (OR) and 95% confidence interval (95% CI) estimates were pooled in either fixed or random effects models.

Results

A total of 23 relevant studies were included after the application of the search strategy. The pooled results showed that statin therapy would downregulate dementia risk according to an analysis of 1,314,431 dementia patients and 1,836,539 healthy controls (OR: 0.64, 95% CI: 0.50, 0.81). In addition, specific changes in mini-mental state examination (MMSE) score were observed in individuals with dementia with statin therapy (OR: 0.46, 95% CI: 0.17, 0.74). However, the results of this meta-analysis showed that statin therapy did not significantly modify the Alzheimer's Disease Assessment Scale (ADAS-cog) score (OR: -0.26, 95% CI: -1.13, 0.62). No significant association was found between statin therapy and activities of daily living performance (OR: -0.69, 95% CI: -4.12, 2.74). When investigating pathological markers, our results indicated a significant influence of statin therapy on plasma amyloid β₄₀ (Aβ₄₀) (OR: 9.27, 95% CI: 0.71, 17.84), plasma Aβ₄₂ (OR: 2.60, 95% CI: 1.07, 4.13), plasma low-density lipoprotein (LDL) cholesterol (OR: -16.95, 95% CI: -25.54, -8.37), plasma lathosterol (OR: -0.11, 95% CI: -0.14, -0.07), plasma 24s-hydroxycholesterol (OR: -10.41, 95% CI: -15.57, -5.25), and cerebrospinal fluid (CSF) lathosterol (OR: -0.07, 95% CI: -0.12, -0.01).

Conclusions

The available data indicate that statin therapy may reduce dementia risk, altering cognitive items and pathologic markers.

Simvastatin Treatment Upregulates HO-1 in Patients with Abdominal Aortic Aneurysm but Independently of Nrf2

Heme oxygenase-1 (HO-1), encoded by HMOX1 gene and regulated by Nrf2 transcription factor, is a cytoprotective enzyme. Its deficiency may exacerbate abdominal aortic aneurysm (AAA) development, which is also often associated with hyperlipidemia. Beneficial effects of statins, the broadly used antilipidemic drugs, were attributed to modulation of Nrf2/HO-1 axis. However, the effect of statins on Nrf2/HO-1 pathway in patients with AAA has not been studied yet. We analyzed AAA tissue from patients treated with simvastatin (N = 28) or without statins (N = 14). Simvastatin treatment increased HO-1 protein level in AAA, both in endothelial cells (ECs) and in smooth muscle cells (SMCs), but increased Nrf2 localization was restricted only to vasa vasorum. Nrf2 target genes HMOX1, NQO1, and GCLM expression remained unchanged in AAA. In vitro studies showed that simvastatin raises HO-1 protein level slightly in ECs and to much higher extent in SMCs, which is not related to Nrf2/ARE activation, although HMOX1 expression is upregulated by simvastatin in both cell types. In conclusion, simvastatin-induced modulation of HO-1 level in ECs and SMCs in vitro is not related to Nrf2/ARE activity. Likewise, divergent HO-1 and Nrf2 localization together with stable expression of Nrf2 target genes, including HMOX1, in AAA tissue denotes Nrf2 independency.

Implications of cerebrovascular ATP-binding cassette transporter G1 (ABCG1) and apolipoprotein M in cholesterol transport at the blood-brain barrier

Impaired cholesterol/lipoprotein metabolism is linked to neurodegenerative diseases such as Alzheimer's disease (AD). Cerebral cholesterol homeostasis is maintained by the highly efficient blood-brain barrier (BBB) and flux of the oxysterols 24(S)-hydroxycholesterol and 27-hydroxycholesterol, potent liver-X-receptor (LXR) activators. HDL and their apolipoproteins are crucial for cerebral lipid transfer, and loss of ATP binding cassette transporters (ABC)G1 and G4 results in toxic accumulation of oxysterols in the brain. The HDL-associated apolipoprotein (apo)M is positively correlated with pre-β HDL formation in plasma; its presence and function in the brain was thus far unknown. Using an in vitro model of the BBB, we examined expression, regulation, and functions of ABCG1, ABCG4, and apoM in primary porcine brain capillary endothelial cells (pBCEC). RT Q-PCR analyses and immunoblotting revealed that in addition to ABCA1 and scavenger receptor, class B, type I (SR-BI), pBCEC express high levels of ABCG1, which was up-regulated by LXR activation. Immunofluorescent staining, site-specific biotinylation and immunoprecipitation revealed that ABCG1 is localized both to early and late endosomes and on apical and basolateral plasma membranes. Using siRNA interference to silence ABCG1 (by 50%) reduced HDL-mediated [³H]-cholesterol efflux (by 50%) but did not reduce [³H]-24(S)-hydroxycholesterol efflux. In addition to apoA-I, pBCEC express and secrete apoM mainly to the basolateral (brain) compartment. HDL enhanced expression and secretion of apoM by pBCEC, apoM-enriched HDL promoted cellular cholesterol efflux more efficiently than apoM-free HDL, while apoM-silencing diminished cellular cholesterol release. We suggest that ABCG1 and apoM are centrally involved in regulation of cholesterol metabolism/turnover at the BBB.

Hedgehog signalling in myeloid cells impacts on body weight, adipose tissue inflammation and glucose metabolism

AIMS/HYPOTHESIS

Recently, hedgehog (Hh) was identified as a crucial player in adipose tissue development and energy expenditure. Therefore, we tested whether Hh ligands are regulated in obesity. Further, we aimed at identifying potential target cells of Hh signalling and studied the functional impact of Hh signalling on adipose tissue inflammation and glucose metabolism.

METHODS

Hh ligands and receptors were analysed in adipose tissue or serum from lean and obese mice as well as in humans. To study the impact on adipose tissue inflammation and glucose metabolism, Hh signalling was specifically blocked in myeloid cells using a conditional knockout approach (Lys-Smo ^-/-).

RESULTS

Desert Hh (DHH) and Indian Hh (IHH) are local Hh ligands, whereas Sonic Hh is not expressed in adipose tissue from mice or humans. In mice, obesity leads to a preferential upregulation of Hh ligands (Dhh) and signalling components (Ptch1, Smo and Gli1) in subcutaneous adipose tissue. Further, adipose tissue macrophages are Hh target cells owing to the expression of Hh receptors, such as Patched1 and 2. Conditional knockout of Smo (which encodes Smoothened, a mandatory Hh signalling component) in myeloid cells increases body weight and adipose tissue inflammation and attenuates glucose tolerance, suggesting an anti-inflammatory effect of Hh signalling. In humans, adipose tissue expression of DHH and serum IHH decrease with obesity and type 2 diabetes, which might be explained by the intake of metformin. Interestingly, metformin reduced Dhh and Ihh expression in mouse adipose tissue explants.

CONCLUSIONS/INTERPRETATION

Hh signalling in myeloid cells affects adipose tissue inflammation and glucose metabolism and may be a potential target to treat type 2 diabetes.

Cholesterol impairment contributes to neuroserpin aggregation

Intraneural accumulation of misfolded proteins is a common feature of several neurodegenerative pathologies including Alzheimer's and Parkinson's diseases, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB). FENIB is a rare disease due to a point mutation in neuroserpin which accelerates protein aggregation in the endoplasmic reticulum (ER). Here we show that cholesterol depletion induced either by prolonged exposure to statins or by inhibiting the sterol reg-ulatory binding-element protein (SREBP) pathway also enhances aggregation of neuroserpin proteins. These findings can be explained considering a computational model of protein aggregation under non-equilibrium conditions, where a decrease in the rate of protein clearance improves aggregation. Decreasing cholesterol in cell membranes affects their biophysical properties, including their ability to form the vesicles needed for protein clearance, as we illustrate by a simple mathematical model. Taken together, these results suggest that cholesterol reduction induces neuroserpin aggregation, even in absence of specific neuroserpin mutations. The new mechanism we uncover could be relevant also for other neurodegenerative diseases associated with protein aggregation.

Selection and Prioritization of Candidate Drug Targets for Amyotrophic Lateral Sclerosis Through a Meta-Analysis Approach

Amyotrophic lateral sclerosis (ALS) is a progressive and incurable neurodegenerative disease. Although several compounds have shown promising results in preclinical studies, their translation into clinical trials has failed. This clinical failure is likely due to the inadequacy of the animal models that do not sufficiently reflect the human disease. Therefore, it is important to optimize drug target selection by identifying those that overlap in human and mouse pathology. We have recently characterized the transcriptional profiles of motor cortex samples from sporadic ALS (SALS) patients and differentiated these into two subgroups based on differentially expressed genes, which encode 70 potential therapeutic targets. To prioritize drug target selection, we investigated their degree of conservation in superoxide dismutase 1 (SOD1) G93A transgenic mice, the most widely used ALS animal model. Interspecies comparison of our human expression data with those of eight different SOD1^G93A datasets present in public repositories revealed the presence of commonly deregulated targets and related biological processes. Moreover, deregulated expression of the majority of our candidate targets occurred at the onset of the disease, offering the possibility to use them for an early and more effective diagnosis and therapy. In addition to highlighting the existence of common key drivers in human and mouse pathology, our study represents the basis for a rational preclinical drug development.

Screening for Small Molecule Inhibitors of Statin-Induced APP C-terminal Toxic Fragment Production

Alzheimer's disease (AD) is characterized by neuronal and synaptic loss. One process that could contribute to this loss is the intracellular caspase cleavage of the amyloid precursor protein (APP) resulting in release of the toxic C-terminal 31-amino acid peptide APP-C31 along with the production of APPΔC31, full-length APP minus the C-terminal 31 amino acids. We previously found that a mutation in APP that prevents this caspase cleavage ameliorated synaptic loss and cognitive impairment in a murine AD model. Thus, inhibition of this cleavage is a reasonable target for new therapeutic development. In order to identify small molecules that inhibit the generation of APP-C31, we first used an APPΔC31 cleavage site-specific antibody to develop an AlphaLISA to screen several chemical compound libraries for the level of N-terminal fragment production. This antibody was also used to develop an ELISA for validation studies. In both high throughput screening (HTS) and validation testing, the ability of compounds to inhibit simvastatin- (HTS) or cerivastatin- (validation studies) induced caspase cleavage at the APP-D720 cleavage site was determined in Chinese hamster ovary (CHO) cells stably transfected with wildtype (wt) human APP (CHO-7W). Several compounds, as well as control pan-caspase inhibitor Q-VD-OPh, inhibited APPΔC31 production (measured fragment) and rescued cell death in a dose-dependent manner. The effective compounds fell into several classes including SERCA inhibitors, inhibitors of Wnt signaling, and calcium channel antagonists. Further studies are underway to evaluate the efficacy of lead compounds - identified here using cells and tissues expressing wt human APP - in mouse models of AD expressing mutated human APP, as well as to identify additional compounds and determine the mechanisms by which they exert their effects.

Guiding synovial inflammation by macrophage phenotype modulation: an in vitro study towards a therapy for osteoarthritis

OBJECTIVE

The aims of this study were to modulate inflammation in synovial explants with the compounds: dexamethasone, rapamycin, bone morphogenetic protein 7 (BMP-7) and pravastatin, and to investigate the modulatory capacity of the compounds on specific macrophage phenotypes.

DESIGN

Synovial explants from osteoarthritis (OA) patients were treated with 10(-6) M dexamethasone, 100 ng/mL rapamycin, 500 ng/mL BMP-7 or 50 μM pravastatin. Half of the explants were pre-stimulated with IFNγ + TNFα to simulate acute inflammation. Inflammatory state of the synovium was assessed with gene expression analysis. Primary human monocytes were isolated and stimulated towards macrophage phenotypes M(IFNγ + TNFα), M(IL-4) and M(IL-10) with the respective cytokines, followed by treatment with the compounds.

RESULTS

Dexamethasone had an anti-inflammatory effect on IFNγ + TNFα stimulated and osteoarthritic synovium, likely due to suppression of pro-inflammatory M(IFNγ + TNFα) macrophages while enhancing anti-inflammatory M(IL4) and M(IL10) macrophages. Rapamycin and BMP-7 further enhanced inflammation in stimulated synovium, but rapamycin did not have a clear effect on non-stimulated synovium. Rapamycin suppressed M(IL-4) and M(IL-10) macrophages without affecting M(IFNγ + TNFα). BMP-7 suppressed M(IFNγ + TNFα) and enhanced M(IL-10) in the macrophage cultures. Pravastatin did not affect synovium, but enhanced M(IL-10).

CONCLUSIONS

These data indicate that macrophage phenotype modulation can be used to guide joint inflammation and thereby contribute to the development of new therapies to delay the progression of OA. The varying effects of the compounds on synovium of different degrees of inflammation, indicate that the modulatory capacity of the compounds depends on OA stage and underlines the importance of identifying this stadium for adequate treatment.

3-Methylcholanthrene/Aryl-Hydrocarbon Receptor-Mediated Hypertension Through eNOS Inactivation

Endothelial nitric oxide synthase (eNOS) modulates vascular blood pressure and is predominantly expressed in endothelial cells and activated through the protein kinase B (Akt/PKB)-dependent pathway. We previously reported that 3-methylcholanthrene (3MC) activates the aryl hydrocarbon receptor (AhR) and reduces PI3K/Akt phosphorylation. This study investigated the mechanism underlying the downregulatory effects of 3-MC on nitric oxide (NO) production occurring through the AhR/RhoA/Akt-mediated mechanism. The mechanism underlying the effects of 3-MC on eNOS activity and blood pressure was examined in vitro and in vivo through genetic and pharmacological approaches. Results indicated that 3-MC modified heat shock protein 90 (HSP90), caveolin-1, dynein, and eNOS mRNA and protein expression through the AhR/RhoA-dependent mechanism in mouse cerebral vascular endothelial cells (MCVECs) and that 3-MC reduced eNOS phosphorylation through the AhR/RhoA-mediated inactivation of Akt1. The upregulation of dynein expression was associated with decreased eNOS dimer formation (eNOS dimer; an activated form of the enzyme). Coimmunoprecipitation assay results indicated that 3-MC significantly reduced the interaction between eNOS and its regulatory proteins, including Akt1 and HSP90, but increased the interaction between eNOS and caveolin-1. Immunofluorescence and Western blot analysis revealed that 3-MC reduced the amount of membrane-bound activated eNOS, and a modified Griess assay revealed that 3-MC concomitantly reduced NO production. However, simvastatin reduced 3-MC-mediated murine hypertension. Our study results indicate that AhR, RhoA, and eNOS have major roles in blood pressure regulation. Statin intervention might provide a potential therapeutic approach for reducing hypertension caused by 3-MC. J. Cell. Physiol. 232: 1020-1029, 2017. © 2016 Wiley Periodicals, Inc.

Statins and Cognitive Side Effects: What Cardiologists Need to Know

Statins are widely used in secondary and primary prevention of atherosclerotic cardiovascular disease. They reduce cardiovascular events and mortality, and have an excellent safety record. Recent case reports suggest a possible association between statins and adverse effects on cognition. This article reviews recent literature related to statins and cognition and provides recommendations to clinicians. Cognitive considerations should not play a role in decision making for most patients for whom statins are indicated. Future trials of statin, or any novel antilipemic agent should include systematic assessment of cognition.

Novel Applications of Magnetic Cell Sorting to Analyze Cell-Type Specific Gene and Protein Expression in the Central Nervous System

The isolation and study of cell-specific populations in the central nervous system (CNS) has gained significant interest in the neuroscience community. The ability to examine cell-specific gene and protein expression patterns in healthy and pathological tissue is critical for our understanding of CNS function. Several techniques currently exist to isolate cell-specific populations, each having their own inherent advantages and shortcomings. Isolation of distinct cell populations using magnetic sorting is a technique which has been available for nearly 3 decades, although rarely used in adult whole CNS tissue homogenate. In the current study we demonstrate that distinct cell populations can be isolated in rodents from early postnatal development through adulthood. We found this technique to be amendable to customization using commercially available membrane-targeted antibodies, allowing for cell-specific isolation across development and animal species. This technique yields RNA which can be utilized for downstream applications—including quantitative PCR and RNA sequencing—at relatively low cost and without the need for specialized equipment or fluorescently labeled cells. Adding to its utility, we demonstrate that cells can be isolated largely intact, retaining their processes, enabling analysis of extrasomatic proteins. We propose that magnetic cell sorting will prove to be a highly useful technique for the examination of cell specific CNS populations.

Transcriptional analysis reveals distinct subtypes in amyotrophic lateral sclerosis: implications for personalized therapy

Amyotrophic lateral sclerosis (ALS) is an incurable disease, caused by the loss of the upper and lower motor neurons. The lack of therapeutic progress is mainly due to the insufficient understanding of complexity and heterogeneity underlying the pathogenic mechanisms of ALS. Recently, we analyzed whole-genome expression profiles of motor cortex of sporadic ALS patients, classifying them into two subgroups characterized by differentially expressed genes and pathways. Some of the deregulated genes encode proteins, which are primary targets of drugs currently in preclinical or clinical studies for several clinical conditions, including neurodegenerative diseases. In this review, we discuss in-depth the potential role of these candidate targets in ALS pathogenesis, highlighting their possible relevance for personalized ALS treatments.

Statins and the risk of dementia in patients with atrial fibrillation: A nationwide population-based cohort study

BACKGROUND

Atrial fibrillation (AF) is associated with cognitive decline and may contribute to an increased risk of dementia. The goal of the present study was to investigate whether statin use prevented non-vascular dementia in subjects with AF.

METHODS

Data from the National Health Insurance Research Database of Taiwan were used in this study. The study group comprised 51,253 AF subjects aged ≥ 60 years who had received statin treatment. For each study patient, four age- and sex-matched AF subjects without statin exposure were selected as the control group (n=205,012). The risk of non-vascular dementia was compared between the statin and control groups.

RESULTS

During the follow-up period, 17,201 patients experienced non-vascular dementia. The annual incidence of non-vascular dementia was lower in the statin group than in the control group (1.89% vs. 2.20%; p<0.001). Statin use exhibited a protective effect on the occurrence of non-vascular dementia, with an adjusted hazard ratio (HR) of 0.832 (95% confidence interval=0.801-0.864). Among statin types, the use of rosuvastatin was associated with the largest risk reduction (adjusted HR=0.661). Statin exposure duration was related inversely to the risk of non-vascular dementia.

CONCLUSIONS

In this large-scale nationwide cohort study, statin use was associated with a lower risk of non-vascular dementia in AF. Use of more potent statin and longer exposure time may be associated with greater benefits.

Cognitive effects of statin medications

The demonstrated benefits of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) for cardiovascular and cerebrovascular disease are well established in the medical literature, and this class of medications is among those most commonly prescribed in the USA. In 2012, the US Food and Drug Administration issued updated recommendations regarding statin medications, and the panel's comments regarding memory impairment fostered clinical confusion (in part because of the lay media's amplification). Cognitive data from several large epidemiological studies have not reliably demonstrated a robust association between incident cognitive impairment and statin use, with some studies reporting a protective effect, some reporting an increased risk and others finding no association. Although several interventional studies have evaluated statins as a possible adjunctive treatment for Alzheimer's disease, none have clearly demonstrated a benefit. A small number of case series have reported infrequent memory difficulties associated with statin use. In these series, the patients' cognitive symptoms resolved after statin discontinuation. The existing medical literature does not suggest that cognitive considerations should play a major role in medical decision making to prescribe statins for the large majority of patients. As with any medication prescribed for older adults, careful clinical monitoring for side effects should be exercised. If a patient is suspected of having idiosyncratic memory impairment associated with use of a statin medication, the drug can be discontinued. The patient should then be followed with careful clinical observation for 1-3 months for resolution of the cognitive symptoms.

Cholesterol: its regulation and role in central nervous system disorders

Cholesterol is a major constituent of the human brain, and the brain is the most cholesterol-rich organ. Numerous lipoprotein receptors and apolipoproteins are expressed in the brain. Cholesterol is tightly regulated between the major brain cells and is essential for normal brain development. The metabolism of brain cholesterol differs markedly from that of other tissues. Brain cholesterol is primarily derived by de novo synthesis and the blood brain barrier prevents the uptake of lipoprotein cholesterol from the circulation. Defects in cholesterol metabolism lead to structural and functional central nervous system diseases such as Smith-Lemli-Opitz syndrome, Niemann-Pick type C disease, and Alzheimer's disease. These diseases affect different metabolic pathways (cholesterol biosynthesis, lipid transport and lipoprotein assembly, apolipoproteins, lipoprotein receptors, and signaling molecules). We review the metabolic pathways of cholesterol in the CNS and its cell-specific and microdomain-specific interaction with other pathways such as the amyloid precursor protein and discuss potential treatment strategies as well as the effects of the widespread use of LDL cholesterol-lowering drugs on brain functions.