👤 Hanna Dib

Atherosclerotic plaques are the leading cause of cardiovascular events. Single-cell approaches have identified diverse human plaque cell phenotypes but their spatial distribution and interactions remain unclear. Here, intercellular communication patterns in human plaque microenvironments were mapped to reveal novel targets to prevent atherosclerotic events. Spatial transcriptomics (Visium, 10x) from 13 carotid plaques, and single-cell transcriptomics (cells = 51 981) were used to analyse cell phenotypes, cell trajectories, and intercellular communications. Cells contributing to plaque stability were explored using deconvolution of plaque bulk RNA-seq data (n = 78), histology, and survival analyses. Key cells and pathways were validated in apolipoprotein E (Apoe)-/- mice and in vitro. Genome-wide association study enrichment analyses were conducted using summary statistics of atherosclerotic diseases. LINCS L1000 data were used to explore drug repurposing. A fibroblast-like vascular smooth muscle cell (VSMC) phenotype associated with extracellular matrix formation pathways (validated in Apoe-/- mice) emerged as a key regulator of intra-plaque ligand-receptor signalling, in particular in the cap region. A higher proportion of fibroblast-like VSMCs was found in asymptomatics, associated with stable plaque features and predicted a lower risk of future events. Genes specific to this VSMC phenotype were enriched in coronary artery disease and myocardial infarction. Finally, compounds, which could induce key marker genes were identified and validated in vitro. This study provides the first comprehensive spatial transcriptomics map of cell communication in human plaque microenvironments. A pivotal role of a fibroblast-like VSMC, orchestrating intraplaque cell signalling and contributing to plaque stability, was identified. Targeting these cells might present promising novel avenues for therapies. Show less

Alzheimer's disease (AD) is characterized by the gradual deterioration of cognitive functions, speech impairment, and memory loss. It can potentially be treated by targeting the beta-site amyloid precursor protein cleavage enzyme 1 (BACE1), which plays a key role in amyloid plaque formation, neurofibrillary tangles, and hyperphosphorylated tau protein. Current drugs have limitations in terms of safety, efficacy, and blood-brain barrier permeability. In view of this, this study was designed to determine the potential inhibitors of the BACE1 enzyme by virtual screening using a curated library of 415 natural products including terpenoids, phenolic compounds, and alkaloids from different medicinal plants. Based on the docking score and interaction analysis, 50 compounds were selected for the downstream analysis, such as ligand binding interactions, pharmacokinetics, druglikness and physicochemical parameters. Among the lead compounds, Palmatine (compound 45) and Berberine (compound 49), demonstrated optimal drug-likeness and blood-brain barrier permeability among the top compounds. 2-[(9Z,12Z)-heptadeca-9,12-dienyl]-6-hydroxybenzoic acid (compound 4) was inactive in most toxicity parameters. Pharmacophore analysis revealed that Palmatine and Berberine share similar features with the standard, highlighting their potential as effective compounds. Furthermore, structural chemistry analysis provided insights on their shared isoquinoline alkaloid framework, illustrating their structural similarities. Molecular dynamics simulations confirmed the stability of the Palmatine-BACE1 and Berberine-BACE1 complexes during a 50 ns production run. Overall, these findings highlighted the potential of Palmatine and Berberine as promising candidates for the experimental validation and the development of the drugs for the treatment of AD. Show less

Therapies targeting the LPL (lipoprotein lipase) pathway are under development for cardiometabolic disease. Insights into their efficacy-both alone and in combination with existing lipid-lowering therapies-modes of action, and safety of these agents are essential to inform clinical development. Using Mendelian randomization, we aimed to (1) evaluate efficacy, (2) explore shared mechanisms, (3) assess additive effects with approved lipid-lowering drugs, and (4) identify secondary indications and potential adverse effects. We selected triglyceride-lowering genetic variants located in the genes encoding ANGPTL3 (angiopoietin-like 3), ANGPTL4 (angiopoietin-like 4), APOC3 (apolipoprotein C3), and LPL and conducted drug target Mendelian randomization on primary outcomes including coronary artery disease and type 2 diabetes, and secondary outcomes, including apolipoprotein B, waist-to-hip ratio, body mass index, and 233 metabolic biomarkers. We conducted interaction Mendelian randomization analyses in 488 139 UK Biobank participants to test the effect of combination therapy targeting the LPL and LDLR (low-density lipoprotein receptor) pathways. Finally, we investigated potential secondary indications and adverse effects by leveraging genetic association data on 1204 disease end points. Genetically predicted triglyceride lowering through the perturbation of LPL pathway activation targets ANGPTL4, APOC3, and LPL was associated with a lower risk of coronary artery disease and type 2 diabetes and lower apolipoprotein B. Genetically predicted triglyceride lowering through ANGPTL4 was associated with a lower waist-to-hip ratio, suggestive of a favorable body fat distribution. There was no evidence of a multiplicative interaction between genetically proxied perturbation of ANGPTL4, APOC3, and LPL and that of HMGCR (HMG-CoA reductase) and PCSK9 (proprotein convertase subtilisin/kexin type 9) on coronary artery disease and type 2 diabetes, consistent with additive effects. Finally, associations of genetically predicted LPL pathway targeting were supportive of the broad safety of these targets. Our findings provide genetic evidence supporting the efficacy and safety of LPL pathway activation therapies for the prevention of coronary artery disease and type 2 diabetes, alone or in combination with statins or PCSK9 inhibitors. Show less

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline, driven by the accumulation of amyloid-beta plaques and neurofibrillary tangles. It involves the dysfunction of key enzymes such as Acetylcholinesterase (AChE) and β-secretase (BACE1), making them critical targets for therapeutic intervention. In this study we investigated an in-house library of 820 secondary metabolites obtained from Ayurvedic plants against AChE and BACE1 with the aim to discover novel leads for AD. Virtual screening resulted in 15 ligands, mostly belonging to the ursane-type or dammarene-type triterpene saponins of Centella asiatica, reestablishing the potency of this plant in drug discovery against AD. The binding affinities were further verified by molecular dynamics (MD) simulation trajectories, including root mean square fluctuations (RMSF), root mean square deviation (RMSD), hydrogen bonding analysis, Coulomb interaction calculation, Lennard-Jones interactions, and the total interaction energy. Moreover, extensive Principal Component Analysis (PCA) and Gibbs free energy landscape were performed. Our results demonstrated three compounds, namely (S)-eriodictyol 7-O-(6-β-O-trans-p-coumaroyl)-β-d-glucopyranoside, sitoindoside-X and 1,5-di-o-caffeoyl quinic acid as more effective in treating AD due to their comparable drug-like properties. Drug-likeness, structural chemistry, pharmacophore, and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) analysis support their potential for future drug development. To establish the effectiveness of these lead compounds against AD, additional experimental testing should be performed. Show less

Cardiovascular diseases (CVD) have overtaken infectious diseases and are currently the world's top killer. A quite strong linkage between this type of ailments and elevated plasma levels of triglycerides (TG) has been always noticed. Notably, this risk factor is mired in deep confusion, since its role in atherosclerosis is uncertain. One of the explanations that aim to decipher this persistent enigma was provided by apolipoprotein C-III (apoC-III), a small protein historically recognized as an important regulator of TG metabolism. Preeminently, hundreds of studies have been carried out in order to explore the APOC3 genetic background, as well as to establish a correlation between its variants and dyslipidemia-related disorders, pointing to an earnest predictive power for future outcomes. Among several polymorphisms reported within the APOC3, the SstI site in its 3'-untranslated region (3'-UTR) was the most consistently and robustly associated with an increased CVD risk. As more genetic data supporting its importance in cardiovascular events aggregate, it was declared, correspondingly, that apoC-III exerts various atherogenic effects, either by intervening in the function and catabolism of many lipoproteins, or by inducing endothelial inflammation and smooth muscle cells (SMC) proliferation. This review was designed to shed the light on the structural and functional aspects of the APOC3 gene, the existing association between its SstI polymorphism and CVD, and the specific molecular mechanisms that underlie apoC-III pathological implications. In addition, the translation of all these gathered knowledges into preventive and therapeutic benefits will be detailed too. Show less

Liver X receptors (LXRs) are transcription factors known for their role in hepatic cholesterol and lipid metabolism. Though highly expressed in fat, the role of LXR in this tissue is not well characterized. We generated adipose tissue LXRα knockout (ATaKO) mice and showed that these mice gain more weight and fat mass on a high-fat diet compared with wild-type controls. White adipose tissue (WAT) accretion in ATaKO mice results from both a decrease in WAT lipolytic and oxidative capacities. This was demonstrated by decreased expression of the β2- and β3-adrenergic receptors, reduced level of phosphorylated hormone-sensitive lipase, and lower oxygen consumption rates (OCRs) in WAT of ATaKO mice. Furthermore, LXR activation in vivo and in vitro led to decreased adipocyte size in WAT and increased glycerol release from primary adipocytes, respectively, with a concomitant increase in OCR in both models. Our findings show that absence of LXRα in adipose tissue results in elevated adiposity through a decrease in WAT oxidation, secondary to attenuated FA availability. Show less