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Akbar, N.

Publications and source records attributed to Akbar, N..

5 recordsLinked to original sources
bioRxiv2024

hsa-miR-9-5p highly expressed in syncytiotrophoblast-derived extracellular vesicles from early-onset preeclampsia impairs cerebral microvascular endothelial cell pro-angiogenic capacity

BackgroundCerebrovascular complications are the leading cause of maternal mortality associated with preeclampsia. Extracellular vesicles (EVs) containing microRNAs (miRNAs) and derived from syncytiotrophoblast (STB-EVs) are suspected to play a role in these complications. Previously, we found that STB-EVs from the placentas of women with preeclampsia have a higher content of the angiogenesis regulator hsa-miR-9-5p. We now investigate the effects of hsa-miR-9-5p on the proangiogenic properties of brain endothelial cells and identify potential protein targets involved in these processes. MethodsBrain endothelial cells (hCMEC/D3) were treated with hsa-miR-9-5p (0, 5 and 10 nM) to assess cell viability and proliferation. Additionally, cell migration and proteomic profile in hCMEC/D3 treated with hsa-miR-9-5p (10 nM) were also analyzed. ResultsCompared to control, hsa-miR-9-5p significantly reduced hCMEC/D3 cell proliferation and migration without affecting cell viability. Proteomic analysis identified several vital proteins potentially mediating these effects, including vascular endothelial growth factor type C (VEGFC), placental growth factor (PLGF or PGF), and platelet-derived growth factor B (PDGFB). Treatment with hsa-miR-9-5p did not impair the capacity of hCMEC/D3 to respond to tumour necrosis factor- (TNF-). Conclusionhsa-miR-9-5p reduces hCMEC/D3 cell proliferation and migration, and modulates the expression of angiogenic regulators such as VEGFC, PLGF, and PDGFB, without affecting TNF- mediated activation of hCMEC/D3. This suggests that STB-EVs cargo hsa-miR-9-5p may selectively inhibit the proangiogenic capacity of brain endothelial cells. These findings enhance our understanding of cerebrovascular alterations in preeclampsia and may guide future studies and therapeutic interventions.

physiology↗
bioRxiv2023

HDL regulates TGFβ-receptor lipid raft partitioning, restoring contractile features of cholesterol-loaded vascular smooth muscle cells

BackgroundCholesterol-loading of mouse aortic vascular smooth muscle cells (mVSMCs) downregulates miR-143/145, a master regulator of the contractile state downstream of TGF{beta} signaling. In vitro, this results in transitioning from a contractile mVSMC to a macrophage-like state. This process likely occurs in vivo based on studies in mouse and human atherosclerotic plaques. ObjectivesTo test whether cholesterol-loading reduces VSMC TGF{beta} signaling and if cholesterol efflux will restore signaling and the contractile state in vitro and in vivo. MethodsHuman coronary artery (h)VSMCs were cholesterol-loaded, then treated with HDL (to promote cholesterol efflux). For in vivo studies, partial conditional deletion of Tgf{beta}r2 in lineage-traced VSMC mice was induced. Mice wild-type for VSMC Tgf{beta}r2 or partially deficient (Tgf{beta}r2+/-) were made hypercholesterolemic to establish atherosclerosis. Mice were then treated with apoA1 (which forms HDL). ResultsCholesterol-loading of hVSMCs downregulated TGF{beta} signaling and contractile gene expression; macrophage markers were induced. TGF{beta} signaling positively regulated miR-143/145 expression, increasing Acta2 expression and suppressing KLF4. Cholesterol-loading localized TGF{beta} receptors into lipid rafts, with consequent TGF{beta} signaling downregulation. Notably, in cholesterol-loaded hVSMCs HDL particles displaced receptors from lipid rafts and increased TGF{beta} signaling, resulting in enhanced miR-145 expression and decreased KLF4-dependent macrophage features. ApoA1 infusion into Tgf{beta}r2+/- mice restored Acta2 expression and decreased macrophage-marker expression in plaque VSMCs, with evidence of increased TGF{beta} signaling. ConclusionsCholesterol suppresses TGF{beta} signaling and the contractile state in hVSMC through partitioning of TGF{beta} receptors into lipid rafts. These changes can be reversed by promotion of cholesterol efflux, consistent with evidence in vivo. Condensed abstractMany cells identified as macrophage-like in human and mouse atherosclerotic plaques are thought to be of VSMC origin. We identified cholesterol-mediated downregulation of TGF{beta} signaling in vitro in human (h)VSMCs by localization of TGF{beta} receptors in membrane lipid rafts, which was reversed by HDL-mediated cholesterol efflux. This restored VSMC contractile marker (Acta2) and suppressed macrophage marker (CD68) expression by promoting TGF{beta} enhancement of miR-145 expression. In vivo, administration of apoA1 (which forms HDL) to atherosclerotic mice also promoted VSMC Acta2 expression and reduced CD68 expression. Because macrophage-like VSMC are thought to have adverse properties, our studies not only show mechanistically how cholesterol causes their transition, but also suggest that efflux-competent HDL particles may have a therapeutic role by restoring a more favorable phenotypic state of VSMC in atherosclerotic plaques.

molecular biology↗
bioRxiv2023

Multi-organ single-cell RNA-sequencing reveals early hyperglycaemia responses that converge on fibroblast dysregulation

Diabetes causes a range of complications that can affect multiple organs. Hyperglycaemia is an important driver of diabetes-associated complications, mediated by biological processes such as dysfunction of endothelial cells, fibrosis and alterations in leukocyte number and function. Here, we dissected the transcriptional response of key cell types to hyperglycaemia across multiple tissues using single-cell RNA-seq (scRNA-seq) and identified conserved, as well as organ-specific, changes associated with diabetes complications. By studying an early timepoint of diabetes, we focus on biological processes involved in the initiation of the disease, before the later organ-specific manifestations had supervened. We used a mouse model of type 1 diabetes and performed scRNA-seq on cells isolated from the heart, kidney, liver and spleen of streptozotocin-treated and control mice after 8 weeks and assessed differences in cell abundance, gene expression, pathway activation and cell signalling across organs and within organs. In response to hyperglycaemia, endothelial cells, macrophages and monocytes displayed organ-specific transcriptional responses, whereas fibroblasts showed similar responses across organs, exhibiting a myofibroblast-like phenotype with altered metabolic gene expression and increased differentiation of myeloid-derived fibroblasts. Further, we found evidence of endothelial dysfunction in the kidney, and of endothelial to mesenchymal transition in streptozotocin-treated mouse organs. In summary, our study represents the first single-cell and multi-organ analysis of early dysfunction in type 1 diabetes-associated hyperglycaemia, and our large-scale dataset (comprising 67,611 cells) will serve as a starting point, reference atlas, and resource for further investigating the events leading to early diabetic disease.

cell biology↗
bioRxiv2021

ASSOCIATION STUDY OF SIX CANDIDATE GENES WITH MAJOR DEPRESSIVE DISORDER IN THE NORTH-WESTERN POPULATION OF PAKISTAN

People around the world are currently affected by Major Depressive Disorder (MDD). Despite its many aspects, symptoms, manifestations and impacts, efforts have been made to identify the root causes of the disorder. In particular, genetic studies have concentrated on identifying candidate genes for MDD and exploring associations between these genes and some specific group of individuals. The aim of this research was to find out the association between single nucleotide polymorphisms in 6 candidate genes linked to the neurobiology of major depressive disorder in the North-Western population of Pakistan. We performed a case-control analysis, with 400 MDD and 232 controls. A trained psychiatrist or clinical psychologists evaluated the patients. Six polymorphisms were genotyped and tested for allele and genotype association with MDD. There were no statistical variations between MDD patients and healthy controls for genotypic and allelic distribution of all the polymorphisms observed. Thus, our analysis does not support the major role of these polymorphisms in contributing to MDD susceptibility, although it does not preclude minor impact. The statistically significant correlation between six polymorphisms and major depressive disorder in the studied population was not observed. There are inconsistencies in investigations around the world. Future research, including GWAS and association analysis on larger scale should be addressed for further validation and replication of the present findings.

genetics↗