A NOVEL SELECTIVE INHIBITOR FOR PLASMA MEMBRANE CALCIUM ATPase 4 IMPROVES VEGF-MEDIATED ANGIOGENESIS

A thesis submitted in fulfilment of the requirement of the University of Wolverhampton for the degree of Doctor of Philosophy.Ischaemic cardiovascular diseases are the leading cause of death worldwide. Therapeutic angiogenesis provides a valuable tool to treat these conditions by stimulating the growth of new blood vessels in the ischaemic tissue. The pro-angiogenic factor VEGF is the most potent inducer of angiogenesis, and exogenous delivery of VEGF has been a key element of therapeutic strategies. Unfortunately, VEGF-based pro-angiogenic procedures have produced only limited patient benefit. Failure to restore efficient VEGF activity remains a major problem. VEGF-mediated activation of the calcineurin/NFAT signalling pathway has been identified as a crucial regulator of angiogenesis. Our laboratory has recently shown a novel role for the plasma membrane calcium ATPase 4 (PMCA4) protein as a negative regulator of VEGF-induced angiogenesis via interaction with calcineurin. The recent identification of aurintricarboxylic acid (ATA) as a selective inhibitor of PMCA4 prompted us to hypothesise that inhibition of PMCA4 with ATA should enhance VEGF-induced angiogenesis. Here, we show that treatment of endothelial cells with nanomolar concentrations of ATA notably enhances calcineurin/NFAT signalling by disrupting the PMCA4/calcineurin interaction. ATA mediated inhibition of PMCA4 results in a significant increase in endothelial cell motility and in vitro and in vivo blood vessel formation. Low concentrations of ATA do not have any deleterious effects on the viability of endothelial cells or zebrafish embryonic development. However, high ATA concentrations impaired endothelial cell viability, and were associated with toxicity in zebrafish embryos. This study highlights the potential of targeting PMCA4 to improve VEGF-based pro-angiogenic therapeutic strategies. This goal will require the development of refined versions of ATA without associated toxicity, or the identification of novel PMCA4 inhibitors

Poly-Gamma-Glutamic Acid (γ-PGA)-based encapsulation of Adenovirus to evade neutralizing antibodies.

In recent years, there has been an increasing interest in oncolytic adenoviral vectors as an alternative anticancer therapy. The induction of an immune response can be considered as a major limitation of this kind of application. Significant research efforts have been focused on the development of biodegradable polymer poly-gamma-glutamic acid (γ-PGA)-based nanoparticles used as a vector for effective and safe anticancer therapy, owing to their controlled and sustained-release properties, low toxicity, as well as biocompatibility with tissue and cells. This study aimed to introduce a specific destructive and antibody blind polymer-coated viral vector into cancer cells using γ-PGA and chitosan (CH). Adenovirus was successfully encapsulated into the biopolymer particles with an encapsulation efficiency of 92% and particle size of 485 nm using the ionic gelation method. Therapeutic agents or nanoparticles (NPs) that carry therapeutics can be directed specifically to cancerous cells by decorating their surfaces using targeting ligands. Moreover, in vitro neutralizing antibody response against viral capsid proteins can be somewhat reduced by encapsulating adenovirus into γ-PGA-CH NPs, as only 3.1% of the encapsulated adenovirus was detected by anti-adenovirus antibodies in the presented work compared to naked adenoviruses. The results obtained and the unique characteristics of the polymer established in this research could provide a reference for the coating and controlled release of viral vectors used in anticancer therapy.This work was funded by the Ministry of Higher Education and Scientific Research (Iraq). This work was also partially funded by the Research Investment Fund, University of Wolverhampton (Wolverhampton, United Kingdom) and the Italian Ministry of University and Research (MIUR)

Selective inhibition of plasma membrane calcium ATPase 4 improves angiogenesis and vascular reperfusion

Aims Ischaemic cardiovascular disease is a major cause of morbidity and mortality worldwide. Despite promising results from pre-clinical animal models, VEGF-based strategies for therapeutic angiogenesis have yet to achieve successful reperfusion of ischaemic tissues in patients. Failure to restore efficient VEGF activity in the ischaemic organ remains a major problem in current pro-angiogenic therapeutic approaches. Plasma membrane calcium ATPase 4 (PMCA4) negatively regulates VEGF-activated angiogenesis via inhibition of the calcineurin/NFAT signalling pathway. PMCA4 activity is inhibited by the small molecule aurintricarboxylic acid (ATA). We hypothesize that inhibition of PMCA4 with ATA might enhance VEGF-induced angiogenesis. Methods and results We show that inhibition of PMCA4 with ATA in endothelial cells triggers a marked increase in VEGF-activated calcineurin/NFAT signalling that translates into a strong increase in endothelial cell motility and blood vessel formation. ATA enhances VEGF-induced calcineurin signalling by disrupting the interaction between PMCA4 and calcineurin at the endothelial-cell membrane. ATA concentrations at the nanomolar range, that efficiently inhibit PMCA4, had no deleterious effect on endothelial-cell viability or zebrafish embryonic development. However, high ATA concentrations at the micromolar level impaired endothelial cell viability and tubular morphogenesis, and were associated with toxicity in zebrafish embryos. In mice undergoing experimentally-induced hindlimb ischaemia, ATA treatment significantly increased the reperfusion of post-ischaemic limbs. Conclusions Our study provides evidence for the therapeutic potential of targeting PMCA4 to improve VEGF-based pro-angiogenic interventions. This goal will require the development of refined, highly selective versions of ATA, or the identification of novel PMCA4 inhibitors

Aberrant expression of miR-133a in endothelial cells inhibits angiogenesis by reducing pro-angiogenic but increasing anti-angiogenic gene expression

© 2022 The Authors. Published by Springer. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1038/s41598-022-19172-xAngiogenesis is a multi-factorial physiological process deregulated in human diseases characterised by excessive or insufficient blood vessel formation. Emerging evidence highlights a novel role for microRNAs as regulators of angiogenesis. Previous studies addressing the effect of miR-133a expression in endothelial cells during blood vessel formation have reported conflicting results. Here, we have assessed the specific effect of mature miR-133a strands in angiogenesis and the expression of endothelial angiogenic genes. Transfection of miR-133a-3p or -5p mimics in primary human endothelial cells significantly inhibited proliferation, migration, and tubular morphogenesis of transfected cells. Screening of gene arrays related to angiogenic processes, and further validation by TaqMan qPCR, revealed that aberrant expression of miR-133a-3p led to a decrease in the expression of genes encoding pro-angiogenic molecules, whilst increasing those with anti-angiogenic functions. Ingenuity Pathway Analysis of a collection of genes differentially expressed in cells harbouring miR-133a-3p, predicted decreased cellular functions related to vasculature branching and cell cycle progression, underlining the inhibitory role of miR-133a-3p in angiogenic cellular processes. Our results suggest that controlled delivery of miR-133a-3p mimics, or antagomirs in diseased endothelial cells, might open new therapeutic interventions to treat patients suffering from cardiovascular pathologies that occur with excessive or insufficient angiogenesis.This work was supported by the Research Institute in Healthcare Sciences, Faculty of Science and Engineering, University of Wolverhampton (to A.L.A) and by generous donations from the charities “Wolverhampton Coronary Aftercare Support Group” (to A.L.A and J.C) and “Rotha Abraham Bequest” (to A.L.A and J.C). S.A. is the recipient of a University of Wolverhampton-Wolverhampton Royal NHS Trust joint PhD studentship. JMR has received funding from the “La Caixa” Banking Foundation HR18-00068 (to J.M.R.); Spanish Ministerio de Ciencia e Innovación grant RTI2018-099246-B-I00 (MICIU/AEI/FEDER, UE) to J.M.R and the Instituto de Salud Carlos III (CIBER-CV CB16/11/00264) to J.M.R. The Centro Nacional de Investigaciones Cardiovasculares (CNIC) is supported by the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) and the Pro-CNIC Foundation.Published onlin

MIR-133a overexpression impairs endothelial cell migration and tube formation in vitro

This work was supported by the Rotha Abraham Bequest Charity.Published versio

Translation of in vitro-transcribed RNA therapeutics.

Peer reviewed: TrueIn vitro transcribed, modified messenger RNAs (IVTmRNAs) have been used to vaccinate billions of individuals against the SARS-CoV-2 virus, and are currently being developed for many additional therapeutic applications. IVTmRNAs must be translated into proteins with therapeutic activity by the same cellular machinery that also translates native endogenous transcripts. However, different genesis pathways and routes of entry into target cells as well as the presence of modified nucleotides mean that the way in which IVTmRNAs engage with the translational machinery, and the efficiency with which they are being translated, differs from native mRNAs. This review summarises our current knowledge of commonalities and differences in translation between IVTmRNAs and cellular mRNAs, which is key for the development of future design strategies that can generate IVTmRNAs with improved activity in therapeutic applications

Inducers of pulmonary arterial hypertension upregulate the expression of plasma membrane calcium atpase 1 in pulmonary artery smooth muscle cells

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Plasma membrane calcium atpase 1 gene expression increases in vascular smooth muscle cells treated with inducers of pulmonary arterial hypertension

Published versio

PLGA–Nano-Encapsulated Disulfiram Inhibits Hypoxia-Induced NF-κB, Cancer Stem Cells, and Targets Glioblastoma In Vitro and In Vivo

Glioblastoma stem cell (GSC) is the major cause of glioblastoma multiforme (GBM) chemotherapy failure. Hypoxia is one of the determinants of GSC. NF-κB plays a pivotal link between hypoxia and cancer stem cells (CSCs). Disulfiram, an antialcoholism drug, has very strong NF-κB–inhibiting and anti-CSC activity. In this study, the in vitro anti-GSC activity of disulfiram and in vivo anti-GBM efficacy of poly lactic–co-glycolic acid nanoparticle-encapsulated disulfiram (DS-PLGA) were examined. We attempt to elucidate the molecular network between hypoxia and GSCs and also examined the anti-GSC activity of disulfiram in vitro and in vivo. The influence of GSCs and hypoxia on GBM chemoresistance and invasiveness was studied in hypoxic and spheroid cultures. The molecular regulatory roles of NF-κB, hypoxia-inducible factor-1α (HIF1α), and HIF2α were investigated using stably transfected U373MG cell lines. The hypoxia in neurospheres determines the cancer stem cell characteristics of the sphere-cultured GBM cell lines (U87MG, U251MG, U373MG). NF-κB is located at a higher hierarchical position than HIF1α/HIF2α in hypoxic regulatory network and plays a key role in hypoxia-induced GSC characters. DS inhibits NF-κB activity and targets hypoxia-induced GSCs. It showed selective toxicity to GBM cells, eradicates GSCs, and blocks migration and invasion at very low concentrations. DS-PLGA efficaciously inhibits orthotopic and subcutaneous U87MG xenograft in mouse models with no toxicity to vital organs

Plasma membrane calcium ATPase isoform 4 inhibits vascular endothelial growth factor-mediated angiogenesis through interaction with calcineurin.

Vascular endothelial growth factor (VEGF) has been identified as a crucial regulator of physiological and pathological angiogenesis. Among the intracellular signaling pathways triggered by VEGF, activation of the calcineurin/nuclear factor of activated T cells (NFAT) signaling axis has emerged as a critical mediator of angiogenic processes. We and others previously reported a novel role for the plasma membrane calcium ATPase (PMCA) as an endogenous inhibitor of the calcineurin/NFAT pathway, via interaction with calcineurin, in cardiomyocytes and breast cancer cells. However, the functional significance of the PMCA/calcineurin interaction in endothelial pathophysiology has not been addressed thus far. Using in vitro and in vivo assays, we here demonstrate that the interaction between PMCA4 and calcineurin in VEGF-stimulated endothelial cells leads to downregulation of the calcineurin/NFAT pathway and to a significant reduction in the subsequent expression of the NFAT-dependent, VEGF-activated, proangiogenic genes RCAN1.4 and Cox-2. PMCA4-dependent inhibition of calcineurin signaling translates into a reduction in endothelial cell motility and blood vessel formation that ultimately impairs in vivo angiogenesis by VEGF. Given the importance of the calcineurin/NFAT pathway in the regulation of pathological angiogenesis, targeted modulation of PMCA4 functionality might open novel therapeutic avenues to promote or attenuate new vessel formation in diseases that occur with angiogenesis