Biology subjects

Ahmetaj-Shala, B.

Publications and source records attributed to Ahmetaj-Shala, B..

4 recordsLinked to original sources

bioRxiv2022

Tissue fibroblasts are a critical source of prostacyclin and anti-thrombotic

Prostacyclin is one of the bodies fundamental signalling pathways. It has long been considered principally anti-thrombotic hormone derived from the vascular endothelium. The role of non-vascular sources in prostacyclin synthesis has not been systematically evaluated, however, due to a lack of tools resulting in an underappreciation of its role in other contexts. Here we used cellspecific knockout mice and human tissues to show that lung, and other tissues, are powerful producers of prostacyclin independent of their vascular components. Instead, in mice and humans, lung prostacyclin synthesis is associated with fibroblasts. The fibroblast-derived prostaglandins enter the circulation and provide systemic anti-thrombotic protection. These observations define a new paradigm in prostacyclin biology in which fibroblast/non-vascular-derived prostacyclin works in parallel with endothelium-derived prostaglandins to control cardiovascular health and potentially a broad range of other biology. These results may explain how local diseases of the lung and elsewhere result in cardiovascular risk.

pharmacology and toxicology↗

bioRxiv2020

Resistance of endothelial cells to SARS-CoV-2 infection in vitro

RationaleThe secondary thrombotic/vascular clinical syndrome of COVID-19 suggests that SARS-CoV-2 infects not only respiratory epithelium but also the endothelium activating thrombotic pathways, disrupting barrier function and allowing access of the virus to other organs of the body. However, a direct test of susceptibility to SARS-CoV-2 of authentic endothelial cell lines has not been performed. ObjectiveTo determine infectibility of primary endothelial cell lines with live SARS-CoV-2 and pseudoviruses expressing SARS-CoV-2 spike protein. Methods and ResultsExpression of ACE2 and BSG pathways genes was determined in three types of endothelial cells; blood outgrowth, lung microvascular and aortic endothelial cells. For comparison nasal epithelial cells, Vero E6 cells (primate kidney fibroblast cell line) and HEK 293T cells (human embryonic kidney cells) transfected with either ACE2 or BSG were used as controls. Endothelial and Vero E6 cells were treated with live SARS-CoV-2 virus for 1 hour and imaged at 24 and 72 hours post infection. Pseudoviruses containing SARS-CoV-2, Ebola and Vesicular Stomatis Virus glycoproteins were generated and added to endothelial cells and HEK 239Ts for 2 hours and infection measured using luminescence at 48 hours post infection. Compared to nasal epithelial cells, endothelial cells expressed low or undetectable levels of ACE2 and TMPRSS2 but comparable levels of BSG, PPIA and PPIB. Endothelial cells showed no susceptibility to live SARS-CoV-2 or SARS-CoV-2 pseudovirus (but showed susceptibility to Ebola and Vesicular Stomatitis Virus). Overexpression of ACE2 but not BSG in HEK 239T cells conferred SARS-CoV-2 pseudovirus entry. Endothelial cells primed with IL-1{beta} remained resistant to SARS-CoV-2. ConclusionEndothelial cells are resistant to infection with SARS-CoV-2 virus, in line with relatively low levels of ACE2 and TMPRSS2, suggesting that the vascular dysfunction and thrombosis seen in severe COVID-19 is a result of factors released by adjacent infected cells (e.g. epithelial cells) and/or circulating, systemic inflammatory mediators.

immunology↗

bioRxiv2020

Systemic analysis of putative SARS-CoV-2 entry and processing genes in cardiovascular tissues identifies a positive correlation of BSG with age in endothelial cells

COVID-19, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has rapidly spread throughout the world with unprecedented global healthcare and socio-economic consequences. There is now an established secondary syndrome of COVID-19 characterised by thrombosis, vascular dysfunction and hypertension, seen in those most severely affected. Advancing age in adults is the single most significant risk factor for hospitalisation and death with COVID-19. In light of the cardiovascular/thrombotic sequalae associated with severe COVID-19 disease and the overwhelming risk that increased age carries, in this study, our aim was to obtain mechanistic insight by interrogating gene expression profiles in cardiovascular tissues and cells. Our focus was on the two putative receptors for SARS-CoV-2, ACE2 and BSG along with a selected range of genes thought to be involved in virus binding/processing. In this study we have made four important observations: (i)Cardiovascular tissues and/or endothelial cells express the required genes for SARS-CoV-2 infection, (ii) SASR-CoV-2 receptor pathways, ACE2/TMPRSS2 and BSG/PPIB(A) polarise to lung/epithelium and vessel/endothelium respectively, (iii) expression of SARS-CoV-2 host genes are, on the whole, relatively stable with age and (iv) notable exceptions were ACE2 which decreases with age in some tissues and BSG which increases with age in endothelial cells. Our data support the idea that that BSG is the dominate pathway utilised by SARS-CoV-2 in endothelial cells and are the first to demonstrate a positive correlation with age. We suggest BSG expression in the vasculature is a critical driver which explains the heightened risk of severe disease and death observed in those >40 years of age. Since BSG is utilised by other pathogens our findings have implications beyond the current pandemic. Finally, because BSG is functions in a range of cardiovascular diseases and fibrosis, our observations may have relevance to our understanding of the diseases associated with aging.

immunology↗

bioRxiv2019

Metal-organic framework (MOF) nanomedicine preparations of sildenafil designed for the future treatment of pulmonary arterial hypertension

Pulmonary Arterial Hypertension (PAH) is an aggressive disease with poor prognosis, no available cure, and low survival rates. Currently, there are several classes of vasodilator drugs that are widely used as treatment strategies for PAH. These include (i) endothelin-1 receptor antagonists, (ii) phosphodiesterase type 5 inhibitors, (iii) prostacyclin analogues, and (iv) soluble guanylate cyclase activators. Despite their clinical benefits, these therapies are hindered by their systemic side effects. This limitation could be overcome by controlled drug release, with future modifications for targeted drug delivery, using a nanomedicine approach. In the current study, we have evaluated one particular nanomedicine platform (the highly porous iron-based metal-organic framework (MOF) commonly referred to as MIL-89) as a carrier of the PAH drug sildenafil. We have previously shown that MIL-89 is relatively non-toxic in a range of human cell types and well tolerated in vivo. Here we prepared a nano-formulation of MIL-89 (nanoMIL-89) and then successfully charged it with a payload of sildenafil (sil@nanoMIL-891). sil@nanoMIL-89 was then shown to release sildenafil in a biphasic manner with an initial rapid release over 6 hours followed by a more sustained release over 72 hours. Both nanoMIL-89 and sil@nanoMIL-89 were relatively non-toxic when incubated with human endothelial cells for 24 hours. Finally, the vasodilator effect of sil@nanoMIL-89 was measured over 8 hours using isolated mouse aorta. Consistent with drug release kinetics, sil@nanoMIL-89 induced vasodilation after a lag phase of >4 hours. Thus, in sil@nanoMIL-89, we have produced a nano-formulation of sildenafil displaying delayed drug release corresponding to vasodilator activity. Further pharmacological assessment of sil@nanoMIL-89, including in PAH models, is now required and constitutes the subject of ongoing investigation.

pharmacology and toxicology↗