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Macro- and microvascular endothelial dysfunction modulation by VCAM1 haplotypes of pediatric sickle cell anemia patients

2020-06Conference object Open access
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dc.contributor.authorSilva, Marisa
dc.contributor.authorVargas, Sofia
dc.contributor.authorCoelho, Andreia
dc.contributor.authorFaustino, Paula
dc.date.accessioned2021-03-13T15:32:27Z
dc.date.available2021-03-13T15:32:27Z
dc.date.issued2020-06
dc.description.abstractSickle cell anemia (SCA) is a multifactorial-like monogenic disease that results from homozygosity for the HBB:c.20A>T mutation. Children with SCA usually present a systemic vascular disease with profound effects in organs like the brain, with stroke being the most severe end of the cerebral vasculopathy spectrum. Endothelial dysfunction plays a major role in vasculopathy and several adhesion molecules, such as vascular cell adhesion molecule 1 (VCAM-1), are produced by a cytokine-activated endothelium. In previous genotype/phenotype association studies, we found positive associations of specific VCAM1 gene promoter variants and haplotypes to high blood flow velocities in the median cerebral artery, and to chronic hemolysis biochemical markers. Our aims in this study were to: (i) assess the role of those variants, together with imaging, serological and hematological parameters as potential biomarkers of cerebral vasculopathy in SCA children, and (ii) evaluate the functional effects of the VCAM1 promoter haplotypes on endothelial cell response following endothelial activation by TNF-alpha stimulation. We investigated seventy children with SCA of sub-Saharan ancestry, with focussing on cerebral vasculopathy, as well as on stroke risk (as measured by transcranial Doppler ultrasound). PCR and Sanger sequencing were used for genotyping VCAM-1 gene. Statistical analyses were performed using SPSS (v.25.0) software. When statistical significance was identified for specific haplotypes, plasmid constructs were created by molecular cloning using a promoterless pGL4.10[luc2] vector. Haplotype sequence of each construct was confirmed by Sanger sequencing prior to transfection to EAhy926 and HBEC (macrovascular and microvascular endothelial cell models, respectively) with and without TNF-alpha stimulation. Differences in promoter activity were then assessed by luciferase reporter assays. We analysed 6 VCAM1 promoter variants and 7 haplotypes with potential modulating effect. The rs1409419_T allele and haplotype 7 (Hap7) were positively associated with stroke, stroke risk, and high levels of LDH. On the other hand, haplotype 1 (Hap1) was negatively associated with stroke. Luciferase reporter assays showed differences in promoter activity, in both endothelial cell models, as a result of Hap1 and Hap7 transfection. Hap1 endothelial cell transfection led to a decrease, while Hap7 transfection led to an increase in promoter activity. These results are consistent with: (i) lower VCAM1 expression, hence a protective effect, due to Hap1 and (ii) higher expression due to Hap7 and consequently, increased vasculopathy risk, in a pro-inflammatory milieu. The association between specific haplotypes and endothelial cell response further enhances the modifier effect of VCAM1 not only on macro- and microvascular endothelial dysfunction but also on systemic SCA vasculopathy. Furthermore, we suggest that those haplotypes, together with the imaging, biochemical and hematological parameters, may be used to design a sensitive and specific biomarker panel for SCA vasculopathy risk, severity and prognosis.pt_PT
dc.description.versioninfo:eu-repo/semantics/publishedVersionpt_PT
dc.identifier.urihttp://hdl.handle.net/10400.18/7447
dc.language.isoengpt_PT
dc.peerreviewedyespt_PT
dc.subjectSickle Cell Diseasept_PT
dc.subjectVCAM1pt_PT
dc.subjectDoenças Genéticaspt_PT
dc.subjectHemoglobinopatiaspt_PT
dc.subjectDrepanocitosept_PT
dc.subjectVasculopatia Cerebralpt_PT
dc.subjectModificadores Genéticospt_PT
dc.subjectAnemiapt_PT
dc.titleMacro- and microvascular endothelial dysfunction modulation by VCAM1 haplotypes of pediatric sickle cell anemia patientspt_PT
dc.typeconference object
dspace.entity.typePublication
oaire.citation.conferencePlaceFrankfurt, Germany (online)pt_PT
oaire.citation.title25th European Haematology Association Congress "Unfolding the future!", 11-14 June 2020pt_PT
person.familyNameFaustino
person.givenNamePaula
person.identifier.ciencia-idF01A-353A-433E
person.identifier.orcid0000-0002-6269-4867
person.identifier.ridM-3519-2014
person.identifier.scopus-author-id8158641100
rcaap.rightsopenAccesspt_PT
rcaap.typeconferenceObjectpt_PT
relation.isAuthorOfPublication94303e78-8b7d-4e24-811d-3af3b1a4e330
relation.isAuthorOfPublication.latestForDiscovery94303e78-8b7d-4e24-811d-3af3b1a4e330

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