RESUMO
BackgroundHepatitis E virus (HEV) is an emerging public health concern in high-income countries and can cause acute and chronic hepatitis. Reported numbers of indigenously acquired HEV infection have increased in the past decade in many European countries. Since 2010, the National Reference Centre (NRC) for Hepatitis Viruses has been testing samples of suspected hepatitis E cases in Belgium.AimIn this surveillance report, we present the epidemiological trends of symptomatic HEV infections in Belgium, from the distribution by age, sex and geography to the molecular characterisation of the viral strains.MethodSerum samples of suspected cases sent to the NRC between 2010 and 2017 were analysed for the presence of HEV-specific IgM and RNA. Virus was sequenced for genotyping and phylogenetic analysis in all samples containing sufficient viral RNA.ResultsThe NRC reported an increase in the number of samples from suspected cases (from 309 to 2,663 per year) and in the number of laboratory-confirmed hepatitis E cases (from 25 to 117 per year). Among 217 sequenced samples, 92.6% were genotype 3 (HEV-3), followed by 6.5% of genotype 1 and 0.9% of genotype 4. HEV-3 subtype viruses were mainly 3f, 3c and 3e. HEV-3f was the most common subtype until 2015, while HEV-3c became the most common subtype in 2016 and 2017.ConclusionThe increasing trend of HEV diagnoses in Belgium may be largely explained by increased awareness and testing.
Assuntos
Vírus da Hepatite E/isolamento & purificação , Hepatite E/epidemiologia , Vigilância da População , RNA Viral/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Bélgica/epidemiologia , Ensaio de Imunoadsorção Enzimática , Feminino , Genótipo , Hepatite E/sangue , Hepatite E/diagnóstico , Vírus da Hepatite E/classificação , Vírus da Hepatite E/genética , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Filogenia , Filogeografia , RNA Viral/sangue , Análise de Sequência de DNA , Estudos Soroepidemiológicos , Fatores SexuaisRESUMO
The interactions of hematopoietic stem and progenitor cells (HSPCs) with extracellular matrix (ECM) components and cells from the bone marrow (BM) microenvironment control their homeostasis. Regenerative BM conditions can induce expression of the ECM protein transforming growth factor beta-induced gene H3 (TGFBI or BIGH3) in murine HSPCs. In this study, we examined how increased or reduced TGFBI expression in human HSPCs and BM mesenchymal stromal cells (MSCs) affects HSPC maintenance, differentiation, and migration. HSPCs that overexpressed TGFBI showed accelerated megakaryopoiesis, whereas granulocyte differentiation and proliferation of granulocyte, erythrocyte, and monocyte cultures were reduced. In addition, both upregulation and downregulation of TGFBI expression impaired HSPC colony-forming capacity of HSPCs. Interestingly, the colony-forming capacity of HSPCs with reduced TGFBI levels was increased after long-term co-culture with MSCs, as measured by long-term culture-colony forming cell (LTC-CFC) formation. Moreover, TGFBI downregulation in HSPCs resulted in increased cobblestone area-forming cell (CAFC) frequency, a measure for hematopoietic stem cell (HSC) capacity. Concordantly, TGFBI upregulation in HSPCs resulted in a decrease of CAFC and LTC-CFC frequency. These results indicate that reduced TGFBI levels in HSPCs enhanced HSC maintenance, but only in the presence of MSCs. In addition, reduced levels of TGFBI in MSCs affected MSC/HSPC interaction, as observed by an increased migration of HSPCs under the stromal layer. In conclusion, tight regulation of TGFBI expression in the BM niche is essential for balanced HSPC proliferation and differentiation.
Assuntos
Proliferação de Células/genética , Proteínas da Matriz Extracelular/genética , Células-Tronco Hematopoéticas/citologia , Células-Tronco Mesenquimais/citologia , Células-Tronco/citologia , Fator de Crescimento Transformador beta/genética , Células da Medula Óssea/citologia , Diferenciação Celular/genética , Linhagem Celular , Movimento Celular/genética , Lissencefalia Cobblestone/genética , Técnicas de Cocultura , Citometria de Fluxo , Regulação da Expressão Gênica no Desenvolvimento , Vetores Genéticos , Hematopoese/genética , Células-Tronco Hematopoéticas/metabolismo , Humanos , Lentivirus/genética , Células-Tronco Mesenquimais/metabolismo , Células-Tronco/metabolismoRESUMO
Cell adhesion and migration are important determinants of homing and development of hematopoietic stem and progenitor cells (HSPCs) in bone marrow (BM) niches. The extracellular matrix protein transforming growth factor-ß (TGF-ß) inducible gene H3 (BIGH3) is involved in adhesion and migration, although the effect of BIGH3 is highly cell type-dependent. BIGH3 is abundantly expressed by mesenchymal stromal cells, while its expression in HSPCs is relatively low unless induced by certain BM stressors. Here, we set out to determine how BIGH3 modulates HSPC adhesion and migration. We show that primary HSPCs adhere to BIGH3-coated substrates, which is, in part, integrin-dependent. Overexpression of BIGH3 in HSPCs and HL60 cells reduced the adhesion to the substrate fibronectin in adhesion assays, which was even more profound in electrical cell-substrate impedance sensing (ECIS) assays. Accordingly, the CXCL12 induced migration over fibronectin-coated surface was reduced in BIGH3-expressing HSPCs. The integrin expression profile of HSPCs was not altered upon BIGH3 expression. Although expression of BIGH3 did not alter actin polymerization in response to CXCL12, it inhibited the PMA-induced activation of the small GTPase RAC1 as well as the phosphorylation and activation of extracellular-regulated kinases (ERKs). Reduced activation of ERK and RAC1 may be responsible for the inhibition of cell adhesion and migration by BIGH3 in HSPCs. Induced BIGH3 expression upon BM stress may contribute to the regulation of BM homeostasis.
