The role of HIF-1alpha in epigenetic regulation of transcription

The oxygen level inside cells, determine the amount of HIF protein. By directly being involved in HIF protein turnover rates, through a mechanism, by which, oxygen is utilized as a co-factor, for the PHD enzymes, regulating HIF protein stability. This allows for rapid stabilization of the HIFs and subsequent gene activation during low oxygen tensions inside cells. I investigated the role of HIF specific epigenetic effects, in cancer cell line models, as well as primary mouse CD8+ T-lymphocytes. The data in Paper I illustrates how HIF has the ability to modulate chromatin through a HIF-1α dependent chromatin remodeling event, in hypoxia responsive gene promoters. We were able to show how, during hypoxic incubations of cancer cell line models HepG2 and SK-N-Be(2)c, hypoxia target gene promoters were remodeled, removing auxiliary factors bound to DNA. Possibly giving access to transcription factor binding. We identified two separate nucleosome free regions (NFRs) in hypoxia target genes, inducible NFRs and constitutive NFRs. The latter, were characterized by no initial remodeling event during hypoxia, conversely, the inducible NFRs required HIF-1α for remodeling to occur. In Paper II we sought to identify the isoform specific effects of HIF-1α and HIF-2α in mouse primary CD8+ T-lymphocytes. We observed that HIF-1α was necessary for proper T-cell activation and cytotoxic function, by using mouse tumor xenograft models, showing decreased tumor size control in HIF-1α knockout T-cells. In contrast, HIF-2α knockout T-cells, activated properly, and controlled tumor size as well as control cells. VEGFA, a known HIF-1α target gene, conditional knockout in T-lymphocytes, showed increased tumor growth, in xenograft studies, as well, increased chemotherapeutic response. This finding, illustrates the complex nature of the tumor microenvironment, the role of the HIFα isoforms, as well as, VEGFA ́s role in modulating tumor vessels and the ability for chemotherapeutics to be successfully delivered. It has been shown that T-lymphocytes accumulated 2-hydroxyglutaric acid stereoisomers R/S-2HG in a HIF-1α dependent fashion. Were S-2HG, have important biological roles for CD8+ T-cell function. In Paper III we identified the epigenetic effects of S-2HG during T-cell activation ex vivo, by following epigenetic modification changes through time. Our findings, illustrate how S-2HG metabolite decreases the overall acetylation of histone tails, at the histone 3 lysine 9 mark. The acetylation of histone proteins, has been widely studied, and is associated with increases in gene transcription. The global decreases in histone acetylation, observed by exogenous administration of S-2HG, might be a plausible mechanism for how, T-lymphocytes change their epigenome during activation

Economic and tourism indicators as a means of monitoring sustainable tourism: The case of inland Istria

This paper analyses indicators to study the sustainability of tourism in inland Istria, which comprises 24 municipalities and towns belonging to Istria County. Taking into account the criteria of availability, reliability, predictability, clarity and feasibility, the following quantitative indicators were used: the Indicator of Tourist Operation (ITO), the Modified Importance Index of major tourism centres (Im), the Specific Overnights Threshold (SOT), tourism-related taxes in the budgets of municipalities and towns, company investments into tourism and hospitality, and the number of employees in tourism and hospitality. According to the ITO indicator, Predominant Tourism Activity was recorded only in Oprtalj Municipality. Being a measure of the spatial distribution of a specific economic activity, the Modified Importance Index established that in all municipalities and towns of inland Istria tourism is either poorly developed or in its incipient stage. The SOT indicator suggests that tourism has no negative effects on local economies and that tourism-related taxes make a minor contribution to the revenue side of municipal and town budgets. Company investment in tourism and hospitality and the number of employees in these industries are indicators that reveal that inland Istria is only beginning to develop into a tourism region. The quantitative indicators were confirmed by the results of qualitative indicators obtained through problem-focused interviews with the representatives of municipalities, towns and local tourist boards. The singular conclusion derived from the interviews was that tourism is a desirable activity, is in its initial stage of development, and is not a threat to local economies. The results of the study confirm the hypothesis that inland Istria is a region of sustainable tourism currently in the involvement stage of the destination lifecycle

Sustainable event tourism: Case study city of Pula, Croatia

Modern tourism expands through cultural experience, which is reflected in economic, ecological and socio-cultural effects on destinations. Event tourism is a growing market segment and represents a challenge for all destination stakeholders. As the largest town in the Croatian part of Istria, the City of Pula represents a valid basis for the development of event tourism due to its coastal geography and rich cultural and historical heritage from antique, medieval and new age periods. The festival and event organisers in Pula use historical and cultural themes in order to develop annual attractions by which they draw in tourists and brand the destination. In this paper, the hypothesis is set on the lack of benefits from event organisation in the destination (the City of Pula) in the ecological, economic and socio-cultural senses. In resolving of research problems with authorised representatives of local boards Arena, Monte Zaro and Stinjan, standardised, semi-structured and problem-centred interviews were conducted for the purposes of contribution to research relative to sustainability and responsibility of events in tourism

An HIF-1α/VEGF-A Axis in Cytotoxic T Cells Regulates Tumor Progression.

Cytotoxic T cells infiltrating tumors are thought to utilize HIF transcription factors during adaptation to the hypoxic tumor microenvironment. Deletion analyses of the two key HIF isoforms found that HIF-1α, but not HIF-2α, was essential for the effector state in CD8+ T cells. Furthermore, loss of HIF-1α in CD8+ T cells reduced tumor infiltration and tumor cell killing, and altered tumor vascularization. Deletion of VEGF-A, an HIF target gene, in CD8+ T cells accelerated tumorigenesis while also altering vascularization. Analyses of human breast cancer showed inverse correlations between VEGF-A expression and CD8+ T cell infiltration, and a link between T cell infiltration and vascularization. These data demonstrate that the HIF-1α/VEGF-A axis is an essential aspect of tumor immunity

Guidance counselors experience of the digital change during covid-19

Från när det första fallet av covid-19 upptäcktes i Sverige i början på 2020, tills att restriktionerna lyftes och covid-19 inte längre klassades som en samhällsfarlig sjukdom i början på våren 2022, har studie- och yrkesvägledare behövt anpassa sitt arbete från fysisk vägledning på campus till digital vägledning genom program som Zoom och Google Meet. Just därför är studiens syfte att undersöka studie- och yrkesvägledares upplevelse av den digitala vägledningen under coronapandemin och om digitaliseringen har ändrat hur vägledare arbetar. Studiens frågeställningar är hur har coronapandemin påverkat förutsättningarna för vägledningssamtal och hur har studie- och yrkesvägledares upplevelse varit av den digitala vägledningen under coronapandemin? Studien använder sig av en kvalitativ intervjumetod men en semistrukturerad intervjuguide för att tillåta vägledarna att utveckla sina svar. Svaren har kategoriserats i fyra teman och dessa teman har analyserats med hjälp av Arne Malténs kommunikationsteori och Gerard Egans SOLER-modell för att förklara studie- och yrkesvägledares upplevelse av den digitala vägledningen. Begrepp som verbal kommunikation, icke-verbala kommunikation, kontext, en- och tvåvägskommunikation används för att förklara studie- och yrkesvägledarnas upplevelse av den digitala vägledningen. Resultatet som studien kommer fram till är att digital vägledning upplevs sakna icke verbal kommunikation men att vägledarna kan använda det som ett komplement till fysisk vägledning.

Guidance counselors experience of the digital change during covid-19

Från när det första fallet av covid-19 upptäcktes i Sverige i början på 2020, tills att restriktionerna lyftes och covid-19 inte längre klassades som en samhällsfarlig sjukdom i början på våren 2022, har studie- och yrkesvägledare behövt anpassa sitt arbete från fysisk vägledning på campus till digital vägledning genom program som Zoom och Google Meet. Just därför är studiens syfte att undersöka studie- och yrkesvägledares upplevelse av den digitala vägledningen under coronapandemin och om digitaliseringen har ändrat hur vägledare arbetar. Studiens frågeställningar är hur har coronapandemin påverkat förutsättningarna för vägledningssamtal och hur har studie- och yrkesvägledares upplevelse varit av den digitala vägledningen under coronapandemin? Studien använder sig av en kvalitativ intervjumetod men en semistrukturerad intervjuguide för att tillåta vägledarna att utveckla sina svar. Svaren har kategoriserats i fyra teman och dessa teman har analyserats med hjälp av Arne Malténs kommunikationsteori och Gerard Egans SOLER-modell för att förklara studie- och yrkesvägledares upplevelse av den digitala vägledningen. Begrepp som verbal kommunikation, icke-verbala kommunikation, kontext, en- och tvåvägskommunikation används för att förklara studie- och yrkesvägledarnas upplevelse av den digitala vägledningen. Resultatet som studien kommer fram till är att digital vägledning upplevs sakna icke verbal kommunikation men att vägledarna kan använda det som ett komplement till fysisk vägledning.

Modified Hypoxia-Inducible Factor Expression in CD8+ T Cells Increases Antitumor Efficacy.

Adoptive transfer of antitumor cytotoxic T cells is an emerging form of cancer immunotherapy. A key challenge to expanding the utility of adoptive cell therapies is how to enhance the survival and function of the transferred T cells. Immune-cell survival requires adaptation to different microenvironments and particularly to the hypoxic milieu of solid tumors. The hypoxia-inducible factor (HIF) transcription factors are an essential aspect of this adaptation. In this study, we undertook experiments to define structural determinants of HIF that potentiate antitumor efficacy in cytotoxic T cells. We first created retroviral vectors to deliver ectopic expression of HIF1α and HIF2α in mouse CD8+ T cells, together or individually and with or without sensitivity to the oxygen-dependent HIFα inhibitors Von Hippel-Lindau and factor-inhibiting HIF (FIH). HIF2α, but not HIF1α, drove broad transcriptional changes in CD8+ T cells, resulting in increased cytotoxic differentiation and cytolytic function against tumor targets. A specific mutation replacing the hydroxyl group-acceptor site for FIH in HIF2α gave rise to the most effective antitumor T cells after adoptive transfer in vivo In addition, codelivering an FIH-insensitive form of HIF2α with an anti-CD19 chimeric antigen receptor greatly enhanced cytolytic function of human CD8+ T cells against lymphoma cells both in vitro and in a xenograft adoptive transfer model. These experiments point to a means to increase the antitumor efficacy of therapeutic CD8+ T cells via ectopic expression of the HIF transcription factor.See related Spotlight on p. 364