Detection of SARS-CoV-2 B.1.1.529 (Omicron) variant by SYBR Green-based RT-qPCR

The coronavirus disease 2019 (COVID-19) pandemic is unceasingly spreading across the globe, and recently a highly transmissible Omicron SARS-CoV-2 variant (B.1.1.529) has been discovered in South Africa and Botswana. Rapid identification of this variant is essential for pandemic assessment and containment. However, variant identification is mainly being performed using expensive and time-consuming genomic sequencing. In this study, we propose an alternative RT-qPCR approach for the detection of the Omicron BA.1 variant using a low-cost and rapid SYBR Green method. We have designed specific primers to confirm the deletion mutations in the spike (S Δ143-145) and the nucleocapsid (N Δ31-33) which are characteristics of this variant. For the evaluation, we used 120 clinical samples from patients with PCR-confirmed SARS-CoV-2 infections, and displaying an S-gene target failure (SGTF) when using TaqPath COVID-19 kit (Thermo Fisher Scientific, Waltham, USA) that included the ORF1ab, S, and N gene targets. Our results showed that all the 120 samples harbored S Δ143-145 and N Δ31-33, which was further confirmed by whole-genome sequencing of 10 samples, thereby validating our SYBR Green-based protocol. This protocol can be easily implemented to rapidly confirm the diagnosis of the Omicron BA.1 variant in COVID-19 patients and prevent its spread among populations, especially in countries with high prevalence of SGTF profile.

Molecular properties prediction, anticancer and anti-inflammatory activities of some pyrimido[1,2-b]pyridazin-2-one derivatives

Introduction

The anticancer and anti-inflammatory activities of a novel series of eleven pyrimido[1,2-b]pyridazin-2-one analogues substituted at position 7 were assessed in the current study.

Methods

The physicochemical characteristics were studied using MolSoft software. The antiproliferative activity was investigated by MTT cell viability assay, and cell cycle analysis elucidated the antiproliferative mechanism of action. Western blot analysis examined the expression levels of key pro-apoptotic (Bax, p53) and pro-survival (Bcl-2) proteins. The anti-inflammatory activity was assessed by measuring the production levels of nitric oxide in RAW264.7 cells, and the expression levels of COX-2 enzyme in LPS-activated THP-1 cells. In addition, the gene expression of various pro-inflammatory cytokines (IL-6, IL-8, IL-1β, TNF-α) and chemokines (CCL2, CXCL1, CXCL2, CXCL3) was assessed by RT-qPCR.

Results

Compound 1 bearing a chlorine substituent displayed the highest cytotoxic activity against HCT-116 and MCF-7 cancer cells where IC50 values of 49.35 ± 2.685 and 69.32 ± 3.186 µM, respectively, were achieved. Compound 1 increased the expression of pro-apoptotic proteins p53 and Bax while reducing the expression of pro-survival protein Bcl-2. Cell cycle analysis revealed that compound 1 arrested cell cycle at the G0/G1 phase. Anti-inflammatory assessments revealed that compound 1 displayed the strongest inhibitory activity on NO production with IC50 of 29.94 ± 2.24 µM, and down-regulated the expression of COX-2. Compound 1 also induced a statistically significant decrease in the gene expression of various cytokines and chemokines.

Conclusion

These findings showed that the pyrimidine derivative 1 displayed potent anti-inflammatory and anticancer properties in vitro, and can be selected as a lead compound for further investigation.

Lestaurtinib (CEP-701) reduces the duration of limbic status epilepticus in periadolescent rats

BACKGROUND

The timely abortion of status epilepticus (SE) is essential to avoid brain damage and long-term neurodevelopmental sequalae. However, available anti-seizure treatments fail to abort SE in 30% of children. Given the role of the tropomyosin-related kinase B (TrkB) receptor in hyperexcitability, we investigated if TrkB blockade with lestaurtinib (CEP-701) enhances the response of SE to a standard treatment protocol and reduces SE-related brain injury.

METHODS

SE was induced with intra-amygdalar kainic acid in postnatal day 45 rats under continuous electroencephalogram (EEG). Fifteen min post-SE onset, rats received intraperitoneal (i.p.) CEP-701 (KCEP group) or its vehicle (KV group). Controls received CEP-701 or its vehicle following intra-amygdalar saline. All groups received two i.p. doses of diazepam, followed by i.p. levetiracetam at 15 min intervals post-SE onset. Hippocampal TrkB dimer to monomer ratios were assessed by immunoblot 24 hr post-SE, along with neuronal densities and glial fibrillary acid protein (GFAP) levels.

RESULTS

SE duration was 50% shorter in the KCEP group compared to KV (p < 0.05). Compared to controls, SE induced a 1.5-fold increase in TrkB dimerization in KV rats (p < 0.05), but not in KCEP rats which were comparable to controls (p > 0.05). The KCEP group had lower GFAP levels than KV (p < 0.05), and both were higher than controls (p < 0.05). KCEP and KV rats had comparable hippocampal neuronal densities (p > 0.05), and both were lower than controls (p < 0.05).

CONCLUSIONS

Given its established human safety, CEP-701 is a promising adjuvant drug for the timely abortion of SE and the attenuation of SE-related brain injury.

Circulating microRNA profile in response to remdesivir treatment in coronavirus disease 2019 (COVID-19) patients

Coronavirus disease 2019 (COVID-19), a serious infectious disease caused by the recently discovered severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a major global health crisis. Although no specific antiviral drugs have been proven to be fully effective against COVID-19, remdesivir (GS-5734), a nucleoside analogue prodrug, has shown beneficial effects when used to treat severe hospitalized COVID-19 cases. The molecular mechanism underlying this beneficial therapeutic effect is still vaguely understood. In this study, we assessed the effect of remdesivir treatment on the pattern of circulating miRNAs in the plasma of COVID-19 patients, which was analyzed using MiRCURY LNA miRNA miRNome qPCR Panels and confirmed by quantitative real-time RT-PCR (qRT-PCR). The results revealed that remdesivir treatment can restore the levels of miRNAs that are upregulated in COVID-19 patients to the range observed in healthy subjects. Bioinformatics analysis revealed that these miRNAs are involved in diverse biological processes, including the transforming growth factor beta (TGF-β), hippo, P53, mucin-type O-glycan biosynthesis, and glycosaminoglycan biosynthesis signaling pathways. On the other hand, three miRNAs (hsa-miR-7-5p, hsa-miR-10b-5p, and hsa-miR-130b-3p) were found to be upregulated in patients receiving remdesivir treatment and in patients who experienced natural remission. These upregulated miRNAs could serve as biomarkers of COVID-19 remission. This study highlights that the therapeutic potential of remdesivir involves alteration of certain miRNA-regulated biological processes. Targeting of these miRNAs should therefore be considered for future COVID-19 treatment strategies.

Fluorinated Benzofuran and Dihydrobenzofuran as Anti-Inflammatory and Potential Anticancer Agents

Benzofuran and 2,3-dihydrobenzofuran scaffolds are heterocycles of high value in medicinal chemistry and drug synthesis. Targeting inflammation in cancer associated with chronic inflammation is a promising therapy. In the present study, we investigated the anti-inflammatory effects of fluorinated benzofuran and dihydrobenzofuran derivatives in macrophages and in the air pouch model of inflammation, as well as their anticancer effects in the human colorectal adenocarcinoma cell line HCT116. Six of the nine compounds suppressed lipopolysaccharide-stimulated inflammation by inhibiting the expression of cyclooxygenase-2 and nitric oxide synthase 2 and decreased the secretion of the tested inflammatory mediators. Their IC₅₀ values ranged from 1.2 to 9.04 µM for interleukin-6; from 1.5 to 19.3 µM for Chemokine (C-C) Ligand 2; from 2.4 to 5.2 µM for nitric oxide; and from 1.1 to 20.5 µM for prostaglandin E₂. Three novel synthesized benzofuran compounds significantly inhibited cyclooxygenase activity. Most of these compounds showed anti-inflammatory effects in the zymosan-induced air pouch model. Because inflammation may lead to tumorigenesis, we tested the effects of these compounds on the proliferation and apoptosis of HCT116. Two compounds with difluorine, bromine, and ester or carboxylic acid groups inhibited the proliferation by approximately 70%. Inhibition of the expression of the antiapoptotic protein Bcl-2 and concentration-dependent cleavage of PARP-1, as well as DNA fragmentation by approximately 80%, were described. Analysis of the structure-activity relationship suggested that the biological effects of benzofuran derivatives are enhanced in the presence of fluorine, bromine, hydroxyl, and/or carboxyl groups. In conclusion, the designed fluorinated benzofuran and dihydrobenzofuran derivatives are efficient anti-inflammatory agents, with a promising anticancer effect and a combinatory treatment in inflammation and tumorigenesis in cancer microenvironments.

Inhibition of alkaline phosphatase impairs dyslipidemia and protects mice from atherosclerosis

Calcium accumulation in atherosclerotic plaques predicts cardiovascular mortality, but the mechanisms responsible for plaque calcification and how calcification impacts plaque stability remain debated. Tissue-nonspecific alkaline phosphatase (TNAP) recently emerged as a promising therapeutic target to block cardiovascular calcification. In this study, we sought to investigate the effect of the recently developed TNAP inhibitor SBI-425 on atherosclerosis plaque calcification and progression. TNAP levels were investigated in ApoE-deficient mice fed a high-fat diet from 10 weeks of age and in plaques from the human ECLAGEN biocollection (101 calcified and 14 non-calcified carotid plaques). TNAP was inhibited in mice using SBI-425 administered from 10 to 25 weeks of age, and in human vascular smooth muscle cells (VSMCs) with MLS-0038949. Plaque calcification was imaged in vivo with ¹⁸F-NaF-PET/CT, ex vivo with osteosense, and in vitro with alizarin red. Bone architecture was determined with µCT. TNAP activation preceded and predicted calcification in human and mouse plaques, and TNAP inhibition prevented calcification in human VSMCs and in ApoE-deficient mice. More unexpectedly, TNAP inhibition reduced the blood levels of cholesterol and triglycerides, and protected mice from atherosclerosis, without impacting the skeletal architecture. Metabolomics analysis of liver extracts identified phosphocholine as a substrate of liver TNAP, who's decreased dephosphorylation upon TNAP inhibition likely reduced the release of cholesterol and triglycerides into the blood. Systemic inhibition of TNAP protects from atherosclerosis, by ameliorating dyslipidemia, and preventing plaque calcification.

Enrichment in procoagulant microparticles in calcified human aortic valve – role in valvular endothelium alterations and enhanced thrombogenicity

Background

Aortic stenosis (AS) is characterized by endothelial dysfunction (ED), inflammatory cell infiltration, myofibroblastic and osteoblastic differentiation. Subclinical leaflet thrombosis was recently linked to higher rates of stroke and transient ischemic attack after transcatheter aortic valve implantation (TAVI). Procoagulant microparticles (MPs) are associated with ED, inflammation and clot formation. There is limited evidence regarding intra-valvular MPs content and their potential biological effects. This question is particularly relevant in TAVI in which the residing native valve could constitute a source of thrombotic activity enhancing leaflet thrombosis and valve dysfunction.

Purpose

Therefore, we hypothesized that MPs trapped within the native aortic valve contribute to valvular dysfunction including enhanced thrombogenicity.

Methods

Human valves were collected from patients undergoing surgical valve replacement for AS or aortic insufficiency (AI). Pro-thrombotic, pro-inflammatory, and ED markers were identified in the calcified vs non-calcified part of the valves by Western-blot. Calcium content was measured through colorimetric method. MPs were extracted from human pathological valves, and quantified through their prothrombinase activity. Primary cultures of porcine valvular endothelial cells (VEC) were treated with the MPs (10 nmol/L) or thrombin (1U/ml) for 24hrs. Phenotypic change was appreciated through gene expression pattern assessed by RT-qPCR. IL-8 secretion was measured by ELISA.

Results

The phenotype of the AS valve was characterized through increased expression of thrombogenic (tissue factor, thrombomodulin, PAI-1), adhesive (VCAM-1, ICAM-1) and inflammatory (COX-1, COX-2) molecules in the calcified part of the valve. Moreover, MPs content was increased in the calcified vs non-calcified part of the valve or AI valves. MPs levels was correlated with valvular calcium content (R=0.3862: p&lt;0.001). Tissue factor was increased in MPs extracted from AS vs AI. The biological effect of MPs was tested on VEC in-vitro. Results showed dramatic increase in expression of inflammatory cytokines (CXCL10, CCL11, CXCL8, MCP1) adhesion molecules (VCAM-1, ICAM-1, SELP, SELE) and proangiogenic factors (VEGFR2, ANGPTL4) in VEC exposed to MPs (24h) from AS vs AI. Enhanced secretory phenotype was evidenced through IL-8 determination in the supernatant of VEC stimulated with MPs from AS valve.

Conclusion

Calcified aortic valve is a potent reservoir of MPs, acting as a pro-thrombogenic source per se and promoting a switch of VEC phenotype toward prothrombotic, proinflammatory and proangiogenic pattern. These data suggest that MPs released from the native valve constitute an important source of mediators involved in enhanced thrombogenicity and valvular remodeling.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): GERCA-Groupe Etudes Reali Commercia Avignon

Syndecan-1 Is Overexpressed in Human Thoracic Aneurysm but Is Dispensable for the Disease Progression in a Mouse Model

Glycosaminoglycans (GAGs) pooling has long been considered as one of the histopathological characteristics defining thoracic aortic aneurysm (TAA) together with smooth muscle cells (SMCs) apoptosis and elastin fibers degradation. However, little information is known about GAGs composition or their potential implication in TAA pathology. Syndecan-1 (SDC-1) is a heparan sulfate proteoglycan that is implicated in extracellular matrix (ECM) interaction and assembly, regulation of SMCs phenotype, and various aspects of inflammation in the vascular wall. Therefore, the aim of this study was to determine whether SDC-1 expression was regulated in human TAA and to analyze its role in a mouse model of this disease. In the current work, the regulation of SDC-1 was examined in human biopsies by RT-qPCR, ELISA, and immunohistochemistry. In addition, the role of SDC-1 was evaluated in descending TAA in vivo using a mouse model combining both aortic wall weakening and hypertension. Our results showed that both SDC-1 mRNA and protein are overexpressed in the media layer of human TAA specimens. RT-qPCR experiments revealed a 3.6-fold overexpression of SDC-1 mRNA (p = 0.0024) and ELISA assays showed that SDC-1 protein was increased 2.3 times in TAA samples compared with healthy counterparts (221 ± 24 vs. 96 ± 33 pg/mg of tissue, respectively, p = 0.0012). Immunofluorescence imaging provided evidence that SMCs are the major cell type expressing SDC-1 in TAA media. Similarly, in the mouse model used, SDC-1 expression was increased in TAA specimens compared to healthy samples. Although its protective role against abdominal aneurysm has been reported, we observed that SDC-1 was dispensable for TAA prevalence or rupture. In addition, SDC-1 deficiency did not alter the extent of aortic wall dilatation, elastin degradation, collagen deposition, or leukocyte recruitment in our TAA model. These findings suggest that SDC-1 could be a biomarker revealing TAA pathology. Future investigations could uncover the underlying mechanisms leading to regulation of SDC-1 expression in TAA.

The effect of clopidogrel and aspirin on the severity of traumatic brain injury in a rat model

Traumatic Brain Injury (TBI) is one of the leading causes of death and disability worldwide. Aspirin (ASA) and clopidogrel (CLOP) are antiplatelet agents that inhibit platelet aggregation. They are implicated in worsening the intracerebral haemorrhage (ICH) risk post-TBI. However, antiplatelet drugs may also exert a neuroprotective effect post-injury. We determined the impact of aspirin and clopidogrel treatment, alone or in combination, on ICH and brain damage in an experimental rat TBI model. We assessed changes in platelet aggregation and measured serum thromboxane by enzyme immune assay. We also explored a panel of brain damage and apoptosis biomarkers by immunoblotting. Rats were treated with aspirin and/or clopidogrel for 48 h prior to TBI and sacrificed 48 h post-injury. In rats treated with antiplatelet agents prior to TBI, platelet aggregation was completely inhibited, and serum thromboxane was significantly decreased, compared to the TBI group without treatment. TBI increases UCHL-1 and GFAP, but decreases hexokinase expression compared to the non-injured controls. All groups treated with antiplatelet drugs prior to TBI had decreased UCH-L1 and GFAP serum levels compared to the TBI untreated group. Furthermore, the ASA and CLOP single treatments increased the hexokinase serum levels. We confirmed that αII-spectrin cleavage increased post-TBI, with the highest cleavage detected in CLOP-treated rats. Aspirin and/or clopidogrel treatment prior to TBI is a double-edged sword that exerts a dual effect post-injury. On one hand, ASA and CLOP single treatments increase the post-TBI ICH risk, with a further detrimental effect from the ASA + CLOP treatment. On the other hand, ASA and/or CLOP treatments are neuroprotective and result in a favourable profile of TBI injury markers. The ICH risk and the neuroprotection benefits from antiplatelet therapy should be weighed against each other to ameliorate the management of TBI patients.

Inflammation and Microcalcification: A Never-Ending Vicious Cycle in Atherosclerosis?

Inflammatory cells and cytokines are known for long to worsen the development of atherosclerotic plaques in mice, and intense efforts are today devoted to develop anti-inflammatory therapeutic strategies to slow down plaque development. Increasing data indicate that plaque inflammation is intimately associated with microcalcifications, which exert harmful effects eventually culminating with plaque rupture. In this review article, we will first introduce microcalcification location, detection, and effects in atherosclerotic plaques. Then, we will present the numerous data suggesting that inflammatory cells and molecules are responsible for the formation of microcalcifications and the articles showing that microcalcifications stimulate macrophages and smooth muscle cells to produce more pro-inflammatory cytokines. Finally, we will discuss the possibility that microcalcifications might stimulate smooth muscle cells to produce larger and more stable calcifications to stabilize plaques, to exit the vicious cycle associating inflammation and microcalcification in atherosclerotic plaques.

Plasma Kallikrein as a Modulator of Liver Injury/Remodeling

The occurrence and persistence of hepatic injury which arises from cell death and inflammation result in liver disease. The processes that lead to liver injury progression and resolution are still not fully delineated. The plasma kallikrein-kinin system (PKKS) has been shown to play diverse functions in coagulation, tissue injury, and inflammation, but its role in liver injury has not been defined yet. In this study, we have characterized the role of the PKKS at various stages of liver injury in mice, as well as the direct effects of plasma kallikrein on human hepatocellular carcinoma cell line (HepG2). Histological, immunohistochemical, and gene expression analyses were utilized to assess cell injury on inflammatory and fibrotic factors. Acute liver injury triggered by carbon tetrachloride (CCl₄) injection resulted in significant upregulation of the plasma kallikrein gene (Klkb1) and was highly associated with the high mobility group box 1 gene, the marker of cell death (r = 0.75, p < 0.0005, n = 7). In addition, increased protein expression of plasma kallikrein was observed as clusters around necrotic areas. Plasma kallikrein treatment significantly increased the proliferation of CCl₄-induced HepG2 cells and induced a significant increase in the gene expression of the thrombin receptor (protease activated receptor-1), interleukin 1 beta, and lectin–galactose binding soluble 3 (galectin-3) (p < 0.05, n = 4). Temporal variations in the stages of liver fibrosis were associated with an increase in the mRNA levels of bradykinin receptors: beta 1 and 2 genes (p < 0.05; n = 3–10). In conclusion, these findings indicate that plasma kallikrein may play diverse roles in liver injury, inflammation, and fibrosis, and suggest that plasma kallikrein may be a target for intervention in the states of liver injury.

Circulating miRNAs: Potential diagnostic role for coronavirus disease 2019 (COVID-19)

Nowadays, the coronavirus disease (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents a major global health problem. Intensive efforts are being employed to better understand this pathology and develop strategies enabling its early diagnosis and efficient treatment. In this study, we compared the signature of circulating miRNAs in plasma of COVID-19 patients versus healthy donors. MiRCURY LNA miRNA miRNome qPCR Panels were performed for miRNA signature characterization. Individual quantitative real-time PCR (qRT-PCR) was carried out to validate miRNome qPCR results. Receiver-operator characteristic (ROC) curve analysis was applied to assess the diagnostic accuracy of the most significantly deregulated miRNA(s) as potential diagnostic biomarker(s). Eight miRNAs were identified to be differentially expressed with miR-17-5p and miR-142-5p being down-regulated whilst miR-15a-5p, miR-19a-3p, miR-19b-3p, miR-23a-3p, miR-92a-3p and miR-320a being up-regulated in SARS-CoV-2-infected patients. ROC curve analyses revealed an AUC (Areas Under the ROC Curve) of 0.815 (P = 0.031), 0.875 (P = 0.012), and 0.850 (P = 0.025) for miR-19a-3p, miR-19b-3p, and miR-92a-3p, respectively. Combined ROC analyses using these 3 miRNAs showed a greater AUC of 0.917 (P = 0.0001) indicating a robust diagnostic value of these 3 miRNAs. These results suggest that plasma miR-19a-3p, miR-19b-3p, and miR-92a-3p expression levels could serve as potential diagnostic biomarker and/or a putative therapeutic target during SARS-CoV-2-infection.

Drug Repurposing: Promises of Edaravone Target Drug in Traumatic Brain Injury

Edaravone is a potent free-radical scavenger that has been in the market for more than 30 years. It was originally developed in Japan to treat strokes and has been used there since 2001. Aside from its anti-oxidative effects, edaravone demonstrated beneficial effects on proinflammatory responses, nitric oxide production, and apoptotic cell death. Interestingly, edaravone has shown neuroprotective effects in several animal models of diseases other than stroke. In particular, edaravone administration was found to be effective in halting amyotrophic lateral sclerosis (ALS) progression during the early stages. Accordingly, after its success in Phase III clinical studies, edaravone has been approved by the FDA as a treatment for ALS patients. Considering its promises in neurological disorders and its safety in patients, edaravone is a drug of interest that can be repurposed for traumatic brain injury (TBI) treatment. Drug repurposing is a novel approach in drug development that identifies drugs for purposes other than their original indication. This review presents the biochemical properties of edaravone along with its effects on several neurological disorders in the hope that it can be adopted for treating TBI patients.

Tobacco cigarette smoking exacerbates aortic calcification in an early stage of myocardial infarction in a female mouse model

Despite increased social awareness, marketing restraints, tobacco taxation, and available smoking cessation rehab programs, active and passive smoking remain a worldwide challenging epidemic and a key risk factor for cardiovascular diseases development. Although cardiovascular (CV) protection is more pronounced in women than in men due to estrogenic effects, tobacco cigarette smoking exposure seems to alter this protection by modulating estrogen actions via undefined mechanisms. Premenopausal cigarette smoking women are at higher risk of adverse CV effects than non-smokers. In this study, we investigated the impact of cigarette smoking on early CV injury after myocardial infarction (MI) in non-menopausal female mice. Aortic arch calcification, fibrosis, reactive oxygen species, and gene expression of inflammatory and calcification genes were exaggerated in mice exposed to cigarette smoke (CS). These findings suggest that aortic injury following MI, characterized by vascular smooth muscle cells transdifferentiation, calcification, inflammation, and collagen deposition but not cardiac dysfunction is exacerbated with CS exposure. The novel findings of this study highlight the importance of aortic injury on short and long-term prognosis in CS-exposed MI females. Linking those findings to estrogen alteration is probable and entails investigation.

gem-Difluorobisarylic derivatives: design, synthesis and anti-inflammatory effect

Introduction

New fluorinated diaryl ethers and bisarylic ketones were designed and evaluated for their anti-inflammatory effects in primary macrophages.

Methods

The synthesis of the designed molecules started from easily accessible and versatile gem-difluoro propargylic derivatives. The desired aromatic systems were obtained using Diels-Alder/aromatization sequences and this was followed by Pd-catalyzed coupling reactions and, when required, final functionalization steps. Both direct inhibitory effects on cyclooxygenase-1 or -2 activities, protein expression of cyclooxygenase-2 and nitric oxide synthase-II and the production of prostaglandin E₂, the pro-inflammatory nitric oxide and interleukin-6 were evaluated in primary murine bone marrow-derived macrophages in response to lipopolysaccharide. Docking of the designed molecules in cyclooxygenase-1 or -2 was performed.

Results

Only fluorinated compounds exerted anti-inflammatory activities by lowering the secretion of interleukin-6, nitric oxide, and prostaglandin E₂, and decreasing the protein expression of inducible nitric oxide synthase and cyclooxygenase-2 in mouse primary macrophages exposed to lipopolysaccharide, as well as cyclooxygenase activity for some inhibitors with different efficiencies depending on the R-groups. Docking observation suggested an inhibitory role of cyclooxygenase-1 or -2 for compounds A3, A4 and A5 in addition to their capacity to inhibit nitrite, interleukin-6, and nitric oxide synthase-II and cyclooxygenase-2 expression.

Conclusion

The new fluorinated diaryl ethers and bisarylic ketones have anti-inflammatory effects in macrophages. These fluorinated compounds have improved potential anti-inflammatory properties due to the fluorine residues in the bioactive molecules.

Heme oxygenase-1-Dependent anti-inflammatory effects of atorvastatin in zymosan-injected subcutaneous air pouch in mice

Statins exert pleiotropic and beneficial anti-inflammatory and antioxidant effects. We have previously reported that macrophages treated with statins increased the expression of heme oxygenase-1 (HO-1), an inducible anti-inflammatory and cytoprotective stress protein, responsible for the degradation of heme. In the present study, we investigated the effects of atorvastatin on inflammation in mice and analyzed its mechanism of action in vivo. Air pouches were established in 8 week-old female C57BL/6J mice. Atorvastatin (5 mg/kg, i.p.) and/or tin protoporphyrin IX (SnPPIX), a heme oxygenase inhibitor (12 mg/kg, i.p.), were administered for 10 days. Zymosan, a cell wall component of Saccharomyces cerevisiae, was injected in the air pouch to trigger inflammation. Cell number and levels of inflammatory markers were determined in exudates collected from the pouch 24 hours post zymosan injection by flow cytometry, ELISA and quantitative PCR. Analysis of the mice treated with atorvastatin alone displayed increased expression of HO-1, arginase-1, C-type lectin domain containing 7A, and mannose receptor C-type 1 in the cells of the exudate of the air pouch. Flow cytometry analysis revealed an increase in monocyte/macrophage cells expressing HO-1 and in leukocytes expressing MRC-1 in response to atorvastatin. Mice treated with atorvastatin showed a significant reduction in cell influx in response to zymosan, and in the expression of proinflammatory cytokines and chemokines such as interleukin-1α, monocyte chemoattractant protein-1 and prostaglandin E₂. Co-treatment of mice with atorvastatin and tin protoporphyrin IX (SnPPIX), an inhibitor of heme oxygenase, reversed the inhibitory effect of statin on cell influx and proinflammatory markers, suggesting a protective role of HO-1. Flow cytometry analysis of air pouch cell contents revealed prevalence of neutrophils and to a lesser extent of monocytes/macrophages with no significant effect of atorvastatin treatment on the modification of their relative proportion. These findings identify HO-1 as a target for the therapeutic actions of atorvastatin and highlight its potential role as an in vivo anti-inflammatory agent.

Chemical Composition and Biological Activities of Lebanese Pentapera Plant

Background

Due to their chemical constituents and biological properties, plants have long been used to control life-threatening diseases. The flora of Lebanon includes many plants that have already been demonstrated to have medicinal value, and other species, such as Pentapera sicula libanotica, that are yet to be characterized. The present study characterized the chemical composition, anti-oxidant, anti-inflammatory, and anti-proliferative potential of aqueous, ethanol, and methanol extracts derived from the leaves of the Lebanese Pentapera plant.

Material/Methods

High-performance liquid chromatography (HPLC) was used to determine the chemical composition. Gas chromatography (GC) coupled with mass spectrometry (MS) was applied to determine the content of essential oil. DPPH radical scavenging assay was performed to evaluate the anti-oxidant potential. The anti-inflammatory potential was assessed using quantitative real-time PCR (qRT-PCR) by measuring TNF-α, IL-6, and CCL4 mRNA levels, and we assessed Cox-2 and iNOS proteins levels using Western blot (WB) analysis. MTT assay was carried out to determine the anti-proliferative potential.

Results

We identified, mainly in the alcoholic (methanol and ethanol) extracts, distinct bioactive compounds with pharmacological relevance. In parallel, with their phytochemical content, these 2 extracts showed significant anti-oxidant, anti-inflammatory and anti-proliferative capacities.

Conclusion

Pentapera sicula libanotica appears to be a promising pharmacological tool.

Lestaurtinib (CEP-701) modulates the effects of early life hypoxic seizures on cognitive and emotional behaviors in immature rats

Hypoxic encephalopathy of the newborn is a major cause of long-term neurological sequelae. We have previously shown that CEP-701 (lestaurtinib), a drug with an established safety profile in children, attenuates short-term hyperexcitability and tropomyosin-related kinase B (TrkB) receptor activation in a well-established rat model of early life hypoxic seizures (HS). Here, we investigated the potential long-term neuroprotective effects of a post-HS transient CEP-701 treatment. Following exposure to global hypoxia, 10 day old male Sprague-Dawley pups received CEP-701 or its vehicle and were sequentially subjected to the light-dark box test (LDT), forced swim test (FST), open field test (OFT), Morris water maze (MWM), and the modified active avoidance (MAAV) test between postnatal days 24 and 44 (P24-44). Spontaneous seizure activity was assessed by epidural cortical electroencephalography (EEG) between P50 and 100. Neuronal density and glial fibrillary acidic protein (GFAP) levels were evaluated on histological sections in the hippocampus, amygdala, and prefrontal cortex at P100. Vehicle-treated hypoxic rats exhibited significantly increased immobility in the FST compared with controls, and post-HS CEP-701 administration reversed this HS-induced depressive-like behavior (p < 0.05). In the MAAV test, CEP-701-treated hypoxic rats were slower at learning both context-cued and tone-signaled shock-avoidance behaviors (p < 0.05). All other behavioral outcomes were comparable, and no recurrent seizures, neuronal loss, or increase in GFAP levels were detected in any of the groups. We showed that early life HS predispose to long-lasting depressive-like behaviors, and that these are prevented by CEP-701, likely via TrkB modulation. Future mechanistically more specific studies will further investigate the potential role of TrkB signaling pathway modulation in achieving neuroprotection against neonatal HS, without causing neurodevelopmental adverse effects.

Phospholipase D: A new mediator during high phosphate-induced vascular calcification associated with chronic kidney disease

Vascular calcification (VC) is the pathological accumulation of calcium phosphate crystals in one of the layers of blood vessels, leading to loss of elasticity and causing severe calcification in vessels. Medial calcification is mostly seen in patients with chronic kidney disease (CKD) and diabetes. Identification of key enzymes and their actions during calcification will contribute to understand the onset of pathological calcification. Phospholipase D (PLD1, PLD2) is active at the earlier steps of mineralization in osteoblasts and chondrocytes. In this study, we aimed to determine their effects during high-phosphate treatment in mouse vascular smooth muscle cell line MOVAS, in the ex vivo model of the rat aorta, and in the in vivo model of adenine-induced CKD. We observed an early increase in PLD1 gene and protein expression along with the increase in the PLD activity in vascular muscle cell line, during calcification induced by ascorbic acid and β-glycerophosphate. Inhibition of PLD1 by the selective inhibitor VU0155069, or the pan-PLD inhibitor, halopemide, prevented calcification. The mechanism of PLD activation is likely to be protein kinase C (PKC)-independent since bisindolylmaleimide X hydrochloride, a pan-PKC inhibitor, did not affect the PLD activity. In agreement, we found an increase in Pld1 gene expression and PLD activity in aortic explant cultures treated with high phosphate, whereas PLD inhibition by halopemide decreased calcification. Finally, an increase in both Pld1 and Pld2 expression occurred simultaneously with the appearance of VC in a rat model of CKD. Thus, PLD, especially PLD1, promotes VC in the context of CKD and could be an important target for preventing onset or progression of VC.

Axon guidance molecule expression after cell therapy in a mouse model of Parkinson's disease

BACKGROUND

Cell therapy is a promising approach for Parkinson's disease (PD). Others and we have previously shown that transplantation of ventral mesencephalic fetal cells into substantia nigra (SN) in an animal model of PD enables anatomical and functional repair of the degenerated pathway. However, the molecular basis of this repair is still largely unknown.

OBJECTIVE

In this work, we studied the expression of several axon guidance molecules that may be implicated in the repair of the degenerated nigrostriatal pathway.

METHODS

The expression of axon guidance molecules was analyzed using qRT-PCR on five specific regions surrounding the nigrostriatal pathway (ventral mesencephalon (VM), thalamus (Thal), medial forebrain bundle (MFB), nucleus accumbens (NAcc) and caudate putamen (CPu)), one and seven days after lesion and transplantation.

RESULTS

We showed that mRNA expression of specific axon guidance molecules and their receptors is modified in structures surrounding the nigrostriatal pathway, suggesting their involvement in the axon guidance of grafted neurons. Moreover, we highlight a possible new role for semaphorin 7A in this repair.

CONCLUSION

Overall, our data provide a reliable basis to understand how axons of grafted neurons are able to navigate towards their targets and interact with the molecular environment in the adult brain. This should help to improve the efficiency of cell replacement approaches in PD.

Characterization and assessment of potential microRNAs involved in phosphate-induced aortic calcification

Medial artery calcification, a hallmark of type 2 diabetes mellitus and chronic kidney disease (CKD), is known as an independent risk factor for cardiovascular mortality and morbidity. Hyperphosphatemia associated with CKD is a strong stimulator of vascular calcification but the molecular mechanisms regulating this process remain not fully understood. We showed that calcification was induced after exposing Sprague-Dawley rat aortic explants to high inorganic phosphate level (P_i , 6 mM) as examined by Alizarin red and Von Kossa staining. This calcification was associated with high Tissue-Nonspecific Alkaline Phosphatase (TNAP) activity, vascular smooth muscle cells de-differentiation, manifested by downregulation of smooth muscle 22 alpha (SM22α) protein expression which was assessed by immunoblot analysis, immunofluorescence, and trans-differentiation into osteo-chondrocyte-like cells revealed by upregulation of Runt related transcription factor 2 (Runx2), TNAP, osteocalcin, and osteopontin mRNA levels which were determined by quantitative real-time PCR. To unravel the possible mechanism(s) involved in this process, microRNA (miR) expression profile, which was assessed using TLDA technique and thereafter confirmed by individual qRT-PCR, revealed differential expression 10 miRs, five at day 3 and 5 at day 6 post P_i treatment versus control untreated aortas. At day 3, miR-200c, -155, 322 were upregulated and miR-708 and 331 were downregulated. After 6 days of treatment, miR-328, -546, -301a were upregulated while miR-409 and miR-542 were downregulated. Our results indicate that high P_i levels trigger aortic calcification and modulation of certain miRs. These observations suggest that mechanisms regulating aortic calcification might involve miRs, which warrant further investigations in future studies.

Chemical Composition, Antioxidant, Anti-Inflammatory, and Antiproliferative Activities of the Plant Lebanese Crataegus Azarolus L

Background

In the present study, phytochemical screening, antioxidant, anti-inflammatory, and antiproliferative capacities of 3 extracts from leaves of Lebanese Crataegus azarolus L. were evaluated.

Material/Methods

Fresh leaves were dissolved in 3 different solvents: distilled water, ethanol, and methanol. The chemical composition was determined using high-performance liquid chromatography (HPLC) and the content of essential oil of this plant was examined by gas chromatography (GC) coupled with mass spectrometry (MS). The antioxidant potential was evaluated using DPPH radical scavenging and Fe²⁺ chelating activity assays. Anti-inflammatory effect was investigated by measuring the secreted amounts of the proinflammatory mediator PGE₂ using ELISA technique, as well as by assaying the mRNA levels of the proinflammatory cytokines (IL-α, IL-β, and Il-6), chemokines (CCL3 and CCL4) and inflammation-sensitive COX2 and iNOS enzymes using quantitative real-time PCR (qRT-PCR). The antiproliferative effect was evaluated using the XTT viability assay.

Results

The obtained results show that alcohol (methanol and ethanol) extracts were rich in bioactive molecules with medical relevance and exerted substantial antioxidant, anti-inflammatory, and antiproliferative capacities. On the other hand, aqueous extract contained fewer chemical components and exhibited less therapeutic efficiency.

Conclusions

Our observations indicate that Crataegus azarolus L. could be used for treating diseases related to oxidative stress, inflammatory reactions, and uncontrolled cell growth.

TNAP stimulates vascular smooth muscle cell trans-differentiation into chondrocytes through calcium deposition and BMP-2 activation: Possible implication in atherosclerotic plaque stability

Atherosclerotic plaque calcification varies from early, diffuse microcalcifications to a bone-like tissue formed by endochondral ossification. Recently, a paradigm has emerged suggesting that if the bone metaplasia stabilizes the plaques, microcalcifications are harmful. Tissue-nonspecific alkaline phosphatase (TNAP), an ectoenzyme necessary for mineralization by its ability to hydrolyze inorganic pyrophosphate (PP_i), is stimulated by inflammation in vascular smooth muscle cells (VSMCs). Our objective was to determine the role of TNAP in trans-differentiation of VSMCs and calcification. In rodent MOVAS and A7R5 VSMCs, addition of exogenous alkaline phosphatase (AP) or TNAP overexpression was sufficient to stimulate the expression of several chondrocyte markers and induce mineralization. Addition of exogenous AP to human mesenchymal stem cells cultured in pellets also stimulated chondrogenesis. Moreover, TNAP inhibition with levamisole in mouse primary chondrocytes dropped mineralization as well as the expression of chondrocyte markers. VSMCs trans-differentiated into chondrocyte-like cells, as well as primary chondrocytes, used TNAP to hydrolyze PP_i, and PP_i provoked the same effects as TNAP inhibition in primary chondrocytes. Interestingly, apatite crystals, associated or not to collagen, mimicked the effects of TNAP on VSMC trans-differentiation. AP and apatite crystals increased the expression of BMP-2 in VSMCs, and TNAP inhibition reduced BMP-2 levels in chondrocytes. Finally, the BMP-2 inhibitor noggin blocked the rise in aggrecan induced by AP in VSMCs, suggesting that TNAP induction in VSMCs triggers calcification, which stimulates chondrogenesis through BMP-2. Endochondral ossification in atherosclerotic plaques may therefore be induced by crystals, probably to confer stability to plaques with microcalcifications.

Cigarette Smoking-Induced Cardiac Hypertrophy, Vascular Inflammation and Injury Are Attenuated by Antioxidant Supplementation in an Animal Model

Background: Cardiovascular diseases are the leading causes of morbidity and mortality worldwide. Cigarette smoking remains a global health epidemic with associated detrimental effects on the cardiovascular system. In this work, we investigated the effects of cigarette smoke exposure on cardiovascular system in an animal model. The study then evaluated the effects of antioxidants (AO), represented by pomegranate juice, on cigarette smoke induced cardiovascular injury. This study aims at evaluating the effect of pomegranate juice supplementation on the cardiovascular system of an experimental rat model of smoke exposure.

Methods: Adult rats were divided into four different groups: Control, Cigarette smoking (CS), AO, and CS + AO. Cigarette smoke exposure was for 4 weeks (5 days of exposure/week) and AO group received pomegranate juice while other groups received placebo. Assessment of cardiovascular injury was documented by assessing different parameters of cardiovascular injury mediators including: (1) cardiac hypertrophy, (2) oxidative stress, (3) expression of inflammatory markers, (4) expression of Bradykinin receptor 1 (Bdkrb1), Bradykinin receptor 2 (Bdkrb2), and (5) altered expression of fibrotic/atherogenic markers [(Fibronectin (Fn1) and leptin receptor (ObR))].

Results: Data from this work demonstrated that cigarette smoke exposure induced cardiac hypertrophy, which was reduced upon administration of pomegranate in CS + AO group. Cigarette smoke exposure was associated with elevation in oxidative stress, significant increase in the expression of IL-1β, TNFα, Fn1, and ObR in rat's aorta. In addition, an increase in aortic calcification was observed after 1 month of cigarette smoke exposure. Furthermore, cigarette smoke induced a significant up regulation in Bdkrb1 expression level. Finally, pomegranate supplementation exhibited cardiovascular protection assessed by the above findings and partly contributed to ameliorating cardiac hypertrophy in cigarette smoke exposed animals.

Conclusion: Findings from this work showed that cigarette smoking exposure is associated with significant cardiovascular pathology such as cardiac hypertrophy, inflammation, pro-fibrotic, and atherogenic markers and aortic calcification in an animal model as assessed 1 month post exposure. Antioxidant supplementation prevented cardiac hypertrophy and attenuated indicators of atherosclerosis markers associated with cigarette smoke exposure.

Endothelial Microparticles From Acute Coronary Syndrome Patients Induce Premature Coronary Artery Endothelial Cell Aging and Thrombogenicity: Role of the Ang II/AT1 Receptor/NADPH Oxidase-Mediated Activation of MAPKs and PI3-Kinase Pathways

BACKGROUND

Microparticles (MPs) have emerged as a surrogate marker of endothelial dysfunction and cardiovascular risk. This study examined the potential of MPs from senescent endothelial cells (ECs) or from patients with acute coronary syndrome (ACS) to promote premature EC aging and thrombogenicity.

METHODS

Primary porcine coronary ECs were isolated from the left circumflex coronary artery. MPs were prepared from ECs and venous blood from patients with ACS (n=30) and from healthy volunteers (n=4) by sequential centrifugation. The level of endothelial senescence was assessed as senescence-associated β-galactosidase activity using flow cytometry, oxidative stress using the redox-sensitive probe dihydroethidium, tissue factor activity using an enzymatic Tenase assay, the level of target protein expression by Western blot analysis, platelet aggregation using an aggregometer, and shear stress using a cone-and-plate viscometer.

RESULTS

Senescence, as assessed by senescence-associated β-galactosidase activity, was induced by the passaging of porcine coronary artery ECs from passage P1 to P4, and was associated with a progressive shedding of procoagulant MPs. Exposure of P1 ECs to MPs shed from senescent P3 cells or circulating MPs from ACS patients induced increased senescence-associated β-galactosidase activity, oxidative stress, early phosphorylation of mitogen-activated protein kinases and Akt, and upregulation of p53, p21, and p16. Ex vivo, the prosenescent effect of circulating MPs from ACS patients was evidenced only under conditions of low shear stress. Depletion of endothelial-derived MPs from ACS patients reduced the induction of senescence. Prosenescent MPs promoted EC thrombogenicity through tissue factor upregulation, shedding of procoagulant MPs, endothelial nitric oxide synthase downregulation, and reduced nitric oxide-mediated inhibition of platelet aggregation. These MPs exhibited angiotensin-converting enzyme activity and upregulated AT1 receptors and angiotensin-converting enzyme in P1 ECs. Losartan, an AT1 receptor antagonist, and inhibitors of either mitogen-activated protein kinases or phosphoinositide 3-kinase prevented the MP-induced endothelial senescence.

CONCLUSIONS

These findings indicate that endothelial-derived MPs from ACS patients induce premature endothelial senescence under atheroprone low shear stress and thrombogenicity through angiotensin II-induced redox-sensitive activation of mitogen-activated protein kinases and phosphoinositide 3-kinase/Akt. They further suggest that targeting endothelial-derived MP shedding and their bioactivity may be a promising therapeutic strategy to limit the development of an endothelial dysfunction post-ACS.

Mesenchymal stem cells with osteogenic potential in human maxillary sinus membrane: an in vitro study

OBJECTIVES

The aim of our study is to prove and validate the existence of an osteogenic progenitor cell population within the human maxillary Schneiderian sinus membrane (hMSSM) and to demonstrate their potential for bone formation.

MATERIALS AND METHODS

Ten hMSSM samples of approximately 2 × 2 cm were obtained during a surgical nasal approach for treatment of chronic rhinosinusitis and were retained for this study. The derived cells were isolated, cultured, and assayed at passage 3 for their osteogenic potential using the expression of Alkaline phosphatase, alizarin red and Von Kossa staining, flow cytometry, and quantitative real-time polymerase chain reaction.

RESULTS

hMSSM-derived cells were isolated, showed homogenous spindle-shaped fibroblast-like morphology, characteristic of mesenchymal progenitor cells (MPCs), and demonstrated very high expression of MPC markers such as STRO-1, CD44, CD90, CD105, and CD73 in all tested passages. In addition, von Kossa and Alizarin red staining showed significant mineralization, a typical feature of osteoblasts. Moreover, alkaline phosphatase (ALP) activity was significantly increased at days 7, 14, 21, and 28 of culture in hMSSM-derived cells grown in osteogenic medium, in comparison to controls. Furthermore, osteogenic differentiation significantly upregulated the transcriptional expression of osteogenic markers such as ALP, Runt-related transcription factor 2 (Runx-2), bone morphogenetic protein (BMP)-2, osteocalcin (OCN), osteonectin (ON), and osteopontin (OPN), confirming that hMSSM-derived cells are of osteoprogenitor origin. Finally, hMSSM-derived cells were also capable of producing OPN proteins upon culturing in an osteogenic medium.

CONCLUSION

Our data showed that hMSSM holds mesenchymal osteoprogenitor cells capable of differentiating to the osteogenic lineage.

CLINICAL RELEVANCE

hMSSM contains potentially multipotent postnatal stem cells providing a promising clinical application in preimplant and implant therapy.

Deciphering glycomics and neuroproteomic alterations in experimental traumatic brain injury: Comparative analysis of aspirin and clopidogrel treatment

As populations age, the number of patients sustaining traumatic brain injury (TBI) and concomitantly receiving preinjury antiplatelet therapy such as aspirin (ASA) and clopidogrel (CLOP) is rising. These drugs have been linked with unfavorable clinical outcomes following TBI, where the exact mechanism(s) involved are still unknown. In this novel work, we aimed to identify and compare the altered proteome profile imposed by ASA and CLOP when administered alone or in combination, prior to experimental TBI. Furthermore, we assessed differential glycosylation PTM patterns following experimental controlled cortical impact model of TBI, ASA, CLOP, and ASA + CLOP. Ipsilateral cortical brain tissues were harvested 48 h postinjury and were analyzed using an advanced neuroproteomics LC-MS/MS platform to assess proteomic and glycoproteins alterations. Of interest, differential proteins pertaining to each group (22 in TBI, 41 in TBI + ASA, 44 in TBI + CLOP, and 34 in TBI + ASA + CLOP) were revealed. Advanced bioinformatics/systems biology and clustering analyses were performed to evaluate biological networks and protein interaction maps illustrating molecular pathways involved in the experimental conditions. Results have indicated that proteins involved in neuroprotective cellular pathways were upregulated in the ASA and CLOP groups when given separately. However, ASA + CLOP administration revealed enrichment in biological pathways relevant to inflammation and proinjury mechanisms. Moreover, results showed differential upregulation of glycoproteins levels in the sialylated N-glycans PTMs that can be implicated in pathological changes. Omics data obtained have provided molecular insights of the underlying mechanisms that can be translated into clinical bedside settings.

Gallotannin is a DNA damaging compound that induces senescence independently of p53 and p21 in human colon cancer cells

The plant secondary metabolite gallotannin (GT) is the simplest hydrolyzable tannin shown to have anti-carcinogenic properties in several cell lines and to inhibit tumor development in different animal models. Here, we determined if GT induces senescence and DNA damage and investigated the involvement of p53 and p21 in this response. Using HCT116 human colon cancer cells wildtype for p53(+/+) /p21(+/+) and null for p53(+/+) /p21(-/-) or p53(-/-) /p21(+/+) , we found that GT induces senescence independently of p21 and p53. GT was found to increase the production of reactive oxygen species (ROS) by altering the redox balance in the cell, mainly by reducing the levels of glutathione and superoxide dismutase (SOD). Using the key antioxidants N-acetyl cysteine, dithiothreitol, SOD, and catalase, we showed that ROS were partially involved in the senescence response. Furthermore, GT-induced cell cycle arrest in S-phase in all HCT116 cell lines. At later time points, we noticed that p53 and p21 null cells escaped complete arrest and re-entered cell cycle provoking higher rates of multinucleation. The senescence induction by GT was irreversible and was accompanied by significant DNA damage as evidenced by p-H2AX staining. Our findings indicate that GT is an interesting anti colon cancer agent which warrants further study.

Glucose stimulates chondrocyte differentiation of vascular smooth muscle cells and calcification: A possible role for IL-1β

Vascular calcification is a hallmark of type 2 diabetes. Glucose stimulates calcification in culture of vascular smooth muscle cells (VSMCs) but the underlying mechanisms remain obscure. We observed that high glucose levels stimulated mouse and human VSMC trans-differentiation into chondrocytes, with increased levels of Sox9, type II collagen, glycosaminoglycan and Runx2 expression, and increased alkaline phosphatase activity and mineralization. These effects were associated with increased expression of IL-1β, which stimulated alkaline phosphatase and calcification, suggesting that glucose induces chondrocyte differentiation of VSMCs, possibly through IL-1β activation.

Functional and splicing defect analysis of 23 ACVRL1 mutations in a cohort of patients affected by Hereditary Hemorrhagic Telangiectasia

Hereditary Hemorrhagic Telangiectasia syndrome (HHT) or Rendu-Osler-Weber (ROW) syndrome is an autosomal dominant vascular disorder. Two most common forms of HHT, HHT1 and HHT2, have been linked to mutations in the endoglin (ENG) and activin receptor-like kinase 1 (ACVRL1or ALK1) genes respectively. This work was designed to examine the pathogenicity of 23 nucleotide variations in ACVRL1 gene detected in more than 400 patients. Among them, 14 missense mutations and one intronic variant were novels, and 8 missense mutations were previously identified with questionable implication in HHT2. The functionality of missense mutations was analyzed in response to BMP9 (specific ligand of ALK1), the maturation of the protein products and their localization were analyzed by western blot and fluorescence microscopy. The splicing impairment of the intronic and of two missense mutations was examined by minigene assay. Functional analysis showed that 18 out of 22 missense mutations were defective. Splicing analysis revealed that one missense mutation (c.733A>G, p.Ile245Val) affects the splicing of the harboring exon 6. Similarly, the intronic mutation outside the consensus splicing sites (c.1048+5G>A in intron 7) was seen pathogenic by splicing study. Both mutations induce a frame shift creating a premature stop codon likely resulting in mRNA degradation by NMD surveillance mechanism. Our results confirm the haploinsufficiency model proposed for HHT2. The affected allele of ACVRL1 induces mRNA degradation or the synthesis of a protein lacking the receptor activity. Furthermore, our data demonstrate that functional and splicing analyses together, represent two robust diagnostic tools to be used by geneticists confronted with novel or conflicted ACVRL1 mutations.

Thiazole derivatives as inhibitors of cyclooxygenases in vitro and in vivo

Cyclooxygenases (COXs) are important membrane-bound heme containing enzymes important in platelet activation and inflammation. COX-1 is constitutively expressed in most cells whereas COX-2 is an inducible isoform highly expressed in inflammatory conditions. Studies have been carried out to evaluate thiazole derivatives as anti-inflammatory molecules. In this study, we investigated the in vitro and in vivo effects of two novel thiazole derivatives compound 1 (N-[4-(4-hydroxy-3-methoxyphenyl)-1,3-thiazol-2-yl] acetamide) and compound 2 (4-(2-amino-1,3-thiazol-4-yl)-2-methoxyphenol) on prostaglandin E2 (PGE2) production and COX activity in inflammatory settings. Our results reveal a potent inhibition of both compound 1 (IC50 9.01±0.01µM) and 2 (IC50 11.65±6.20µM) (Mean±S.E.M.) on COX-2-dependent PGE2 production. We also determined whether COX-1 activity was inhibited. Using cells stably over-expressing COX-1 and human blood platelets, we showed that compound 1 is a specific inhibitor of COX-1 with IC50 (5.56×10(-8)±2.26×10(-8)µM), whereas compound 2 did not affect COX-1. Both compounds exhibit anti-inflammatory effect in the dorsal air pouch model of inflammation as shows by inhibition of PGE2 secretion. Modeling analysis of docking in the catalytic site of COX-1 or COX-2 further confirmed the difference in the effect of these two compounds. In conclusion, this study contributes to the design of new anti-inflammatory agents and to the understanding of cyclooxygenase inhibition by thiazole.

Fatty acid composition in matrix vesicles and in microvilli from femurs of chicken embryos revealed selective recruitment of fatty acids

Hypertrophic chondrocytes participate in matrix mineralization by releasing matrix vesicles (MVs). These MVs, by accumulating Ca(2+) and phosphate initiate the formation of hydroxyapatite. To determine the types of lipids essential for mineralization, we analyzed fatty acids (FAs) in MVs, microvilli and in membrane fractions of chondrocytes isolated from femurs of chicken embryos. The FA composition in the MVs was almost identical to that in microvilli, indicating that the MVs originated from microvilli. These fractions contained more monounsaturated FAs especially oleic acid than in membrane homogenates of chondrocytes. They were enriched in 5,8,11-eicosatrienoic acid (20:3n-9), in eicosadienoic acid (20:2n-6), and in arachidonic acid (20:4n-6). In contrast, membrane homogenates from chondrocytes were enriched in 20:1n-9, 18:3n-3, 22:5n-3 and 22:5n-6. Due to their relatively high content in MVs and to their selective recruitment within microvilli from where MV originate, we concluded that 20:2n-6 and 20:3n-9 (pooled values), 18:1n-9 and 20:4n-6 are essential for the biogenesis of MVs and for bone mineralization.

Molecular mechanisms of mesenchymal stem cell differentiation towards osteoblasts

Bone is a dynamic tissue that is constantly renewed by the coordinated action of two cell types, i.e., the bone-resorbing osteoclasts and the bone-forming osteoblasts. However, in some circumstances, bone regeneration exceeds bone self repair capacities. This is notably often the case after bone fractures, osteolytic bone tumor surgery, or osteonecrosis. In this regard, bone tissue engineering with autologous or allogenic mesenchymal stem cells (MSCs) is been widely developed. MSCs can be isolated from bone marrow or other tissues such as adipose tissue or umbilical cord, and can be implanted in bone defects with or without prior amplification and stimulation. However, the outcome of most pre-clinical studies remains relatively disappointing. A better understanding of the successive steps and molecular mechanisms involved in MSC-osteoblastic differentiation appears to be crucial to optimize MSC-bone therapy. In this review, we first present the important growth factors that stimulate osteoblastogenesis. Then we review the main transcription factors that modulate osteoblast differentiation, and the microRNAs (miRs) that inhibit their expression. Finally, we also discuss articles dealing with the use of these factors and miRs in the development of new bone MSC therapy strategies. We particularly focus on the studies using human MSCs, since significant differences exist between osteoblast differentiation mechanisms in humans and mice for instance.

Role of nitric oxide and CCAAT/enhancer-binding protein transcription factor in statin-dependent induction of heme oxygenase-1 in mouse macrophages

The effect of statins on heme oxygenase-1 (HO-1) was compared in 2 murine cell lines, RAW 264.7 and J774A.1 cell lines, and in primary peritoneal macrophages of BALB/c or C57BL/6 mice. The role of endogenous nitric oxide and the type of transcription factors involved were explored. Simvastatin and fluvastatin induced HO-1. Pretreatment of cells with l-NMMA or 1400 W, two different nitric oxide synthase inhibitors, partially blocked statin-dependent induction of HO-1 in RAW 264.7 and J774A.1 but not in primary peritoneal macrophages. Induction of HO-1 by statins was dependent on p-38 MAP kinase activation in all types of macrophages. In RAW 264.7 cells, both statins increased the activity of reporter genes linked to the proximal 1.3 kbp promoter of HO-1 (EC50 of 1.4±0.3 µM for simvastatin and 0.6±0.03 µM for fluvastatin). This effect was significantly blocked by 1400 W (80±5.2% inhibition, p<0.02) and mevalonate, the direct metabolite of HMGCoA reductase. Gel retardation experiments implicated C/EBPβ, AP-1 but not USF, for both RAW 264.7 and primary peritoneal macrophages of C57BL/6 mice. Collectively we showed a differential role of endogenous nitric oxide between macrophage cell lines and primary macrophages and an effect of statins in the protection against inflammation by increasing HO-1 expression.

Circulating miR-150 and miR-342 in plasma are novel potential biomarkers for acute myeloid leukemia

BACKGROUND

MicroRNAs (miRNAs) are small (19-22-nt) single-stranded noncoding RNA molecules whose deregulation of expression can contribute to human disease including the multistep processes of carcinogenesis in human. Circulating miRNAs are emerging biomarkers in many diseases and cancers such as type 2 diabetes, pulmonary disease, colorectal cancer, and gastric cancer among others; however, defining a plasma miRNA signature in acute myeloblastic leukemia (AML) that could serve as a biomarker for diagnosis or in the follow-up has not been done yet.

METHODS

TaqMan miRNA microarray was performed to identify deregulated miRNAs in the plasma of AML patients. Quantitative real-time RT-PCR was used to validate the results. Receiver-operator characteristic (ROC) curve analysis was conducted to evaluate the diagnostic accuracy of the highly and significantly identified deregulated miRNA(s) as potential candidate biomarker(s).

RESULTS

The plasma expression level of let-7d, miR-150, miR-339, and miR-342 was down-regulated whilst that of let-7b, and miR-523 was up-regulated in the AML group at diagnosis compared to healthy controls. ROC curve analyses revealed an AUC (the areas under the ROC curve) of 0.835 (95% CI: 0.7119- 0.9581; P<0.0001) and 0.8125 (95% CI: 0.6796-0.9454; P=0.0005) for miR-150, and miR-342 respectively. Combined ROC analyses using these 2 miRNAs revealed an elevated AUC of 0.86 (95% CI: 0.7819-0.94; P<0.0001) indicating the additive effect in the diagnostic value of these 2 miRNAs. QRT-PCR results showed that the expression level of these two miRs in complete remission AML patients resembled that of healthy controls.

CONCLUSIONS

Our findings indicated that plasma miR-150 and miR-342 are novel important promising biomarkers in the diagnosis of AML. These novel and promising markers warrant validation in larger prospective studies.

New analogues of 13-hydroxyocatdecadienoic acid and 12-hydroxyeicosatetraenoic acid block human blood platelet aggregation and cyclooxygenase-1 activity

Background

Thromboxane A₂ is derived from arachidonic acid through the action of cyclooxygenases and thromboxane synthase. It is mainly formed in blood platelets upon activation and plays an important role in aggregation. Aspirin is effective in reducing the incidence of complications following acute coronary syndrome and stroke. The anti-thrombotic effect of aspirin is obtained through the irreversible inhibition of cyclooxygenases. Analogues of 12-hydroxyeicosatetraenoic acid and 13-hydroxyocatdecadienoic acid were shown previously to modulate platelet activation and to block thromboxane receptors.

Results and discussion

We synthesized 10 compounds based on the structures of analogues of 12-hydroxyeicosatetraenoic acid and 13-hydroxyocatdecadienoic acid and evaluated their effect on platelet aggregation triggered by arachidonic acid. The structure activity relationship was evaluated. Five compounds showed a significant inhibition of platelet aggregation and highlighted the importance of the lipidic hydrophobic hydrocarbon chain and the phenol group. Their IC₅₀ ranged from 7.5 ± 0.8 to 14.2 ± 5.7 μM (Mean ± S.E.M.). All five compounds decreased platelet aggregation and thromboxane synthesis in response to collagen whereas no modification of platelet aggregation in response to thromboxane receptor agonist, U46619, was observed. Using COS-7 cells overexpressing human cyclooxygenase-1, we showed that these compounds are specific inhibitors of cyclooxygenase-1 with IC₅₀ ranging from 1.3 to 12 μM. Docking observation of human recombinant cyclooxygenase-1 supported a role of the phenol group in the fitting of cyclooxygenase-1, most likely related to hydrogen bonding with the Tyr 355 of cyclooxygenase-1.

Conclusions

In conclusion, the compounds we synthesized at first based on the structures of analogues of 12 lipoxygenase metabolites showed a role of the phenol group in the anti-platelet and anti-cyclooxygenase-1 activities. These compounds mediate their effects via blockade of cyclooxygenase-1.

Biological and anti-inflammatory evaluation of two thiazole compounds in RAW cell line: potential cyclooxygenase-2 specific inhibitors

The anti-inflammatory effect of two new thiazoles derivatives CX-32 (N-[4-(4-hydroxy-3-methoxyphenyl)-1,3-thiazol-2-yl]acetamide) and CX-35 (4-(2-amino-1,3-thiazol-4-yl)-2-methoxyphenol), was investigated in LPS-stimulated RAW 264.7 cell line. Synthesis, structure analysis and purity of these compounds were evaluated by high performance liquid chromatography, H1 NMR, and C13 NMR. Assessment of CX-32 and CX-35 inhibitory effect on cyclooxygenase-2 (COX-2) activity was achieved by incubating LPS-activated RAW cells with 25 μM, 50 μM or 100 μM of CX-32 or CX-35 respectively. Levels of secreted PGE2 were evaluated by enzyme immunoassay (EIA) and levels of COX-2 protein were measured by western blot. Finally, cell viability experiments were undertaken to assess the toxicity of each compound. Treatment of LPS-activated RAW cells with 25 μM, 50 μM, or 100 μM of CX-35 or CX-32 respectively, prevented the production of prostaglandins, but was without effect on COX-2 protein levels. Moreover, CX-35 and CX-32 reduced PGE2 production to levels comparable to those obtained in LPS-activated RAW cells incubated with the selective COX-2 inhibitor NS 398. Furthermore, both CX-32 and CX-35 showed no toxic effects, since viability of non-treated Hela cells was similar to Hela cells incubated with either CX-35 or CX-32. Our data demonstrated that CX-32 and CX-35 significantly blocked prostaglandin production induced during inflammatory cellular stress, possibly acting through specific COX-2 inhibition; confirmation of this hypothesis requires further investigation.

MicroRNA profile of circulating CD4-positive regulatory T cells in human adults and impact of differentially expressed microRNAs on expression of two genes essential to their function

Regulatory T cells (Tregs) are characterized by a high expression of IL-2 receptor α chain (CD25) and of forkhead box P3 (FOXP3), the latter being essential for their development and function. Another major player in the regulatory function is the cytotoxic T-lymphocyte associated molecule-4 (CTLA-4) that inhibits cytotoxic responses. However, the regulation of CTLA-4 expression remains less well explored. We therefore studied the microRNA signature of circulating CD4(+) Tregs isolated from adult healthy donors and identified a signature composed of 15 differentially expressed microRNAs. Among those, miR-24, miR-145, and miR-210 were down-regulated in Tregs compared with controls and were found to have potential target sites in the 3'-UTR of FOXP3 and CTLA-4; miR-24 and miR-210 negatively regulated FOXP3 expression by directly binding to their two target sites in its 3'-UTR. On the other hand, miR-95, which is highly expressed in adult peripheral blood Tregs, positively regulated FOXP3 expression via an indirect mechanism yet to be identified. Finally, we showed that miR-145 negatively regulated CTLA-4 expression in human CD4(+) adult peripheral blood Tregs by binding to its target site in CTLA-4 transcript 3'-UTR. To our knowledge, this is the first identification of a human adult peripheral blood CD4(+) Treg microRNA signature. Moreover, unveiling one mechanism regulating CTLA-4 expression is novel and may lead to a better understanding of the regulation of this crucial gene.

Arsenic trioxide inhibits ATRA-induced prostaglandin E2 and cyclooxygenase-1 in NB4 cells, a model of acute promyelocytic leukemia

In acute promyelocytic leukemia (APL), all-trans retinoic acid (ATRA) triggers cell differentiation, while arsenic trioxide (As(2)O(3)) generates partial differentiation and apoptosis. Animal and human studies suggest that newly diagnosed APL patients can be cured using As(2)O(3) combined with ATRA. Cyclooxygenases are involved in prostaglandins and thromboxane synthesis. We have recently demonstrated that ATRA induces cyclooxygenase-1 (COX-1) expression and prostaglandin synthesis in NB4 cells and in blasts from patients with APL. In the present study we investigated the effect of ATRA and As(2)O(3) co-treatment on COX-1 expression and prostaglandin formation and tested the effect of the COX-1/COX-2 nonselective inhibitor indomethacin on cell differentiation. Arsenic treatment of NB4 cells resulted in a partial but significant reduction of ATRA-dependent induction of COX-1 expression and activity. Pretreatment of NB4 cells with indomethacin significantly impaired ATRA/As(2)O(3)-induced differentiation, as assessed by cell morphology, nitroblue tetrazolium test or CD11c expression. PGE(2) reversed the negative effect of indomethacin on differentiation of ATRA/As(2)O(3)-treated NB4 cells. In conclusion, COX-1 contributes to ATRA-dependent maturation of NB4 cells and is affected by As(2)O(3). These results also suggest that nonsteroidal antiinflammatory drugs should be avoided in APL patients treated with the combination of ATRA and As(2)O(3).

The roles of annexins and alkaline phosphatase in mineralization process

In this review the roles of specific proteins during the first step of mineralization and nucleation are discussed. Mineralization is initiated inside the extracellular organelles-matrix vesicles (MVs). MVs, containing relatively high concentrations of Ca2+ and inorganic phosphate (Pi), create an optimal environment to induce the formation of hydroxyapatite (HA). Special attention is given to two families of proteins present in MVs, annexins (AnxAs) and tissue-nonspecific alkaline phosphatases (TNAPs). Both families participate in the formation of HA crystals. AnxAs are Ca2+ - and lipid-binding proteins, which are involved in Ca2+ homeostasis in bone cells and in extracellular MVs. AnxAs form calcium ion channels within the membrane of MVs. Although the mechanisms of ion channel formation by AnxAs are not well understood, evidence is provided that acidic pH or GTP contribute to this process. Furthermore, low molecular mass ligands, as vitamin A derivatives, can modulate the activity of MVs by interacting with AnxAs and affecting their expression. AnxAs and other anionic proteins are also involved in the crystal nucleation. The second family of proteins, TNAPs, is associated with Pi homeostasis, and can hydrolyse a variety of phosphate compounds. ATP is released in the extracellular matrix, where it can be hydrolyzed by TNAPs, ATP hydrolases and nucleoside triphosphate (NTP) pyrophosphohydrolases. However, TNAP is probably not responsible for ATP-dependent Ca2+/phosphate complex formation. It can hydrolyse pyrophosphate (PPi), a known inhibitor of HA formation and a byproduct of NTP pyrophosphohydrolases. In this respect, antagonistic activities of TNAPs and NTP pyrophosphohydrolases can regulate the mineralization process.

Chick embryo anchored alkaline phosphatase and mineralization process in vitro

Bone alkaline phosphatase with glycolipid anchor (GPI-bALP) from chick embryo femurs in a medium without exogenous inorganic phosphate, but containing calcium and GPI-bALP substrates, served as in vitro model of mineral formation. The mineralization process was initiated by the formation of inorganic phosphate, arising from the hydrolysis of a substrate by GPI-bALP. Several mineralization media containing different substrates were analysed after an incubation time ranging from 1.5 h to 144 h. The measurements of Ca/Pi ratio and infrared spectra permitted us to follow the presence of amorphous and noncrystalline structures, while the analysis of X-ray diffraction data allowed us to obtain the stoichiometry of crystals. The hydrolysis of phosphocreatine, glucose 1-phosphate, glucose 6-phosphate, glucose 1,6-bisphosphate by GPI-bALP produced hydroxyapatite in a manner similar to that of beta-glycerophosphate. Several distinct steps in the mineral formation were observed. Amorphous calcium phosphate was present at the onset of the mineral formation, then poorly formed hydroxyapatite crystalline structures were observed, followed by the presence of hydroxyapatite crystals after 6-12 h incubation time. However, the hydrolysis of either ATP or ADP, catalysed by GPI-bALP in calcium-containing medium, did not lead to the formation of any hydroxyapatite crystals, even after 144 h incubation time, when hydrolysis of both nucleotides was completed. In contrast, the hydrolysis of AMP by GPI-bALP led to the appearance of hydroxyapatite crystals after 12 h incubation time. The hydroxyapatite formation depends not only on the ability of GPI-bALP to hydrolyze the organic phosphate but also on the nature of substrates affecting the nucleation process or producing inhibitors of the mineralization.

The roles of annexins and alkaline phosphatase in mineralization process

In this review the roles of specific proteins during the first step of mineralization and nucleation are discussed. Mineralization is initiated inside the extracellular organelles-matrix vesicles (MVs). MVs, containing relatively high concentrations of Ca2+ and inorganic phosphate (Pi), create an optimal environment to induce the formation of hydroxyapatite (HA). Special attention is given to two families of proteins present in MVs, annexins (AnxAs) and tissue-nonspecific alkaline phosphatases (TNAPs). Both families participate in the formation of HA crystals. AnxAs are Ca2+ - and lipid-binding proteins, which are involved in Ca2+ homeostasis in bone cells and in extracellular MVs. AnxAs form calcium ion channels within the membrane of MVs. Although the mechanisms of ion channel formation by AnxAs are not well understood, evidence is provided that acidic pH or GTP contribute to this process. Furthermore, low molecular mass ligands, as vitamin A derivatives, can modulate the activity of MVs by interacting with AnxAs and affecting their expression. AnxAs and other anionic proteins are also involved in the crystal nucleation. The second family of proteins, TNAPs, is associated with Pi homeostasis, and can hydrolyse a variety of phosphate compounds. ATP is released in the extracellular matrix, where it can be hydrolyzed by TNAPs, ATP hydrolases and nucleoside triphosphate (NTP) pyrophosphohydrolases. However, TNAP is probably not responsible for ATP-dependent Ca2+/phosphate complex formation. It can hydrolyse pyrophosphate (PPi), a known inhibitor of HA formation and a byproduct of NTP pyrophosphohydrolases. In this respect, antagonistic activities of TNAPs and NTP pyrophosphohydrolases can regulate the mineralization process.