Inhibition of let-7c Regulates Cardiac Regeneration after Cryoinjury in Adult Zebrafish

The let-7c family of micro-RNAs (miRNAs) is expressed during embryonic development and plays an important role in cell differentiation. We have investigated the role of let-7c in heart regeneration after injury in adult zebrafish. let-7c antagomir or scramble injections were given at one day after cryoinjury (1 dpi). Tissue samples were collected at 7 dpi, 14 dpi and 28 dpi and cardiac function was assessed before cryoinjury, 1 dpi, 7 dpi, 14 dpi and 28 dpi. Inhibition of let-7c increased the rate of fibrinolysis, increased the number of proliferating cell nuclear antigen (PCNA) positive cardiomyocytes at 7 dpi and increased the expression of the epicardial marker raldh2 at 7 dpi. Additionally, cardiac function measured with echocardiography recovered slightly more rapidly after inhibition of let-7c. These results reveal a beneficial role of let-7c inhibition in adult zebrafish heart regeneration

Tankyrase Inhibition Attenuates Cardiac Dilatation and Dysfunction in Ischemic Heart Failure

Hyperactive poly(ADP-ribose) polymerases (PARP) promote ischemic heart failure (IHF) after myocardial infarction (MI). However, the role of tankyrases (TNKSs), members of the PARP family, in pathogenesis of IHF remains unknown. We investigated the expression and activation of TNKSs in myocardium of IHF patients and MI rats. We explored the cardioprotective effect of TNKS inhibition in an isoproterenol-induced zebrafish HF model. In IHF patients, we observed elevated TNKS2 and DICER and concomitant upregulation of miR-34a-5p and miR-21-5p in non-infarcted myocardium. In a rat MI model, we found augmented TNKS2 and DICER in the border and infarct areas at the early stage of post-MI. We also observed consistently increased TNKS1 in the border and infarct areas and destabilized AXIN in the infarct area from 4 weeks onward, which in turn triggered Wnt/β-catenin signaling. In an isoproterenol-induced HF zebrafish model, inhibition of TNKS activity with XAV939, a TNKSs-specific inhibitor, protected against ventricular dilatation and cardiac dysfunction and abrogated overactivation of Wnt/β-catenin signaling and dysregulation of miR-34a-5p induced by isoproterenol. Our study unravels a potential role of TNKSs in the pathogenesis of IHF by regulating Wnt/β-catenin signaling and possibly modulating miRNAs and highlights the pharmacotherapeutic potential of TNKS inhibition for prevention of IHF

Vezf1 regulates cardiac structure and contractile function

Background Vascular endothelial zinc finger 1 (Vezf1) is a transcription factor previously shown to regulate vasculogenesis and angiogenesis. We aimed to investigate the role of Vezf1 in the postnatal heart. Methods The role of Vezf1 in regulating cardiac growth and contractile function was studied in zebrafish and in primary cardiomyocytes. Findings We find that expression of Vezf1 is decreased in diseased human myocardium and mouse hearts. Our experimental data shows that knockdown of zebrafish Vezf1 reduces cardiac growth and results in impaired ventricular contractile response to β-adrenergic stimuli. However, Vezf1 knockdown is not associated with dysregulation of cardiomyocyte Ca2+ transient kinetics. Gene ontology enrichment analysis indicates that Vezf1 regulates cardiac muscle contraction and dilated cardiomyopathy related genes and we identify cardiomyocyte Myh7/β-MHC as key target for Vezf1. We further identify a key role for an MCAT binding site in the Myh7 promoter regulating the response to Vezf1 knockdown and show that TEAD-1 is a binding partner of Vezf1. Interpretation We demonstrate a role for Vezf1 in regulation of compensatory cardiac growth and cardiomyocyte contractile function, which may be relevant in human cardiac disease.Peer reviewe

Lähiluonto kasvatuksen tukena : Mynälahti opetuskäyttöön -hanke

Mynälahti opetuskäyttöön -hankkeen tavoitteena oli tuottaa oppimateriaalia Mynälahden alueen koulujen käyttöön. Idea oppimateriaalin luomiseksi tuli alueen opettajilta, jotka kokivat tarvitsevansa ideoita ja koottua tietoa opetuskäyntiensä tueksi Mynälahdelle. Mynälahti on merenlahti, joka sijaitsee Mynämäen kunnassa Varsinais-Suomessa. Mynälahti on erityisesti lintujen muuttoaikana merkittävä lintukohde. Oppimateriaalin kerääminen aloitettiin huolellisella suunnittelulla. Heti alusta otettiin yhteistyöhön mukaan opettajia alueen kouluista. Keskustelu opettajien yhteistyöryhmän kanssa mahdollisti opettajien toiveiden sekä palautteen huomioimisen läpi koko projektin. Hankkeen materiaalin keruussa osallistettiin yhteistyökoulujen oppilaita, jotka laativat materiaalia hankkeelle. Mynälahdelle tehtiin tutustumiskäyntejä, joiden aikana kuvattiin aluetta. Materiaalia kerättiin sekä kirjallisista että sähköisistä lähteistä ja sitä täydennettiin asiantuntija haastatteluilla. Hankkeessa koottua retkikäyttöön tarkoitettua tehtäväopasta testattiin yhteistyökoulujen oppilailla. Koekäytön jälkeen sekä oppilaat että opettajat saivat antaa palautetta, joka huomioitiin lopullisen tehtäväoppaan teossa. Hankkeessa laadittiin Retkiä Mynälahdelle -tehtäväopas ja -internetsivusto. Internetsivusto löytyy osoitteesta http://mynalahti.turkuamk.fi/index.php/retkia-mynalahdelle. Tehtäväopas on saatavilla internetsivuston opettajille tarkoitetussa osiossa. Tehtäväopas on tarkoitettu retkikäyttöön Mynälahdelle sijoittuville retkille. Internetsivusto tarjoaa kattavasti tietoa Mynälahdesta tutkittavaksi luokkatiloissa tai kotioloissa. Valmista oppimateriaalia pyrittiin markkinoimaan laajasti sekä koulujen käyttöön että kaikille Mynälahden alueesta kiinnostuneille. Oppimateriaalin koonnissa onnistuttiin hyvin ja valmis materiaalipaketti on kattava katsaus Mynälahteen. Opettajilta saatujen kommenttien perusteella myös he ovat tyytyväisiä valmiiseen tuotteeseen. Valmistunut materiaali tarjoaa myös mallin, jota voidaan käyttää oppimateriaalin luomiseen muihinkin luontoretkeilykohteisiin.The goal in Mynälahti opetuskäyttöön -project was to produce learning material to the schools nearby Mynälahti. The idea for the learning material came from the teachers who wanted to have new ideas and information about the area to support excursions to Mynälahti. Mynälahti is a gulf which is located in Southwest Finland. The first step in collecting the learning material was careful planning. From the very beginning a number of teachers from the nearby schools worked in close co-operation with the authors. Discussions with teachers were held during the entire project. Through these discussions valuable feedback was received and teachers’ viewpoint was determined. Students from the co-operative schools participated in producing the material. Introductory tours to Mynälahti were conducted with a great number of photographs and filming as a result. Material was collected from electronic and written sources and it was completed with experts´ interviews. One of the goals in the project was to collect an excursion guidebook and it was tested on the students from the co-operative schools. After this test use both students and teachers gave feedback on the excursion guidebook which was considered in the making of the final version of the excursion guidebook. Retkiä Mynälahdelle website and an excursion guidebook were devised during the project. The website can be found at http://mynalahti.turkuamk.fi/index.php/retkia-mynalahdelle. The excursion guidebook can also be found on the website, in the section for teachers. The excursion guidebook is suitable as a teachers´ guidebook used during excursions in Mynälahti. The website offers information about Mynälahti and it can be used in schools or at home by anyone who is interested in Mynälahti. The finished educational material was marketed widely. Many different marketing channels were used for this purpose. The finished learning material is a successful and an extensive overview on Mynälahti. Also teachers´ comments were positive and they were pleased with the material. The finished material can also be used as a template when new material is made for another destination

Zebrafish Heart Failure Models

Heart failure causes significant morbidity and mortality worldwide. The understanding of heart failure pathomechanisms and options for treatment remain incomplete. Zebrafish has proven useful for modeling human heart diseases due to similarity of zebrafish and mammalian hearts, fast easily tractable development, and readily available genetic methods. Embryonic cardiac development is rapid and cardiac function is easy to observe and quantify. Reverse genetics, by using morpholinos and CRISPR-Cas9 to modulate gene function, make zebrafish a primary animal model for in vivo studies of candidate genes. Zebrafish are able to effectively regenerate their hearts following injury. However, less attention has been given to using zebrafish models to increase understanding of heart failure and cardiac remodeling, including cardiac hypertrophy and hyperplasia. Here we discuss using zebrafish to study heart failure and cardiac remodeling, and review zebrafish genetic, drug-induced and other heart failure models, discussing the advantages and weaknesses of using zebrafish to model human heart disease. Using zebrafish models will lead to insights on the pathomechanisms of heart failure, with the aim to ultimately provide novel therapies for the prevention and treatment of heart failure.Peer reviewe

Deficiency of heme oxygenase 1a causes detrimental effects on cardiac function

Humans lacking heme oxygenase 1 (HMOX1) display growth retardation, haemolytic anaemia, and vulnerability to stress; however, cardiac function remains unclear. We aimed to explore the cardiac function of zebrafish lacking hmox1a at baseline and in response to stress. We generated zebrafish hmox1a mutants using CRISPR/Cas9 genome editing technology. Deletion of hmox1a increases cardiac output and further induces hypertrophy in adults. Adults lacking hmox1a develop myocardial interstitial fibrosis, restrain cardiomyocyte proliferation and downregulate renal haemoglobin and cardiac antioxidative genes. Larvae lacking hmox1a fail to respond to hypoxia, whereas adults are insensitive to isoproterenol stimulation in the heart, suggesting that hmox1a is necessary for cardiac response to stress. Haplodeficiency of hmox1a stimulates non-mitochondrial respiration and cardiac cell proliferation, increases cardiac output in larvae in response to hypoxia, and deteriorates cardiac function and structure in adults upon isoproterenol treatment. Intriguingly, haplodeficiency of hmox1a upregulates cardiac hmox1a and hmox1b in response to isoproterenol. Collectively, deletion of hmox1a results in cardiac remodelling and abrogates cardiac response to hypoxia and isoproterenol. Haplodeficiency of hmox1a aggravates cardiac response to the stress, which could be associated with the upregulation of hmox1a and hmox1b. Our data suggests that HMOX1 homeostasis is essential for maintaining cardiac function and promoting cardioprotective effects.Peer reviewe

Tankyrase Inhibition Attenuates Cardiac Dilatation and Dysfunction in Ischemic Heart Failure

Hyperactive poly(ADP-ribose) polymerases (PARP) promote ischemic heart failure (IHF) after myocardial infarction (MI). However, the role of tankyrases (TNKSs), members of the PARP family, in pathogenesis of IHF remains unknown. We investigated the expression and activation of TNKSs in myocardium of IHF patients and MI rats. We explored the cardioprotective effect of TNKS inhibition in an isoproterenol-induced zebrafish HF model. In IHF patients, we observed elevated TNKS2 and DICER and concomitant upregulation of miR-34a-5p and miR-21-5p in non-infarcted myocardium. In a rat MI model, we found augmented TNKS2 and DICER in the border and infarct areas at the early stage of post-MI. We also observed consistently increased TNKS1 in the border and infarct areas and destabilized AXIN in the infarct area from 4 weeks onward, which in turn triggered Wnt/β-catenin signaling. In an isoproterenol-induced HF zebrafish model, inhibition of TNKS activity with XAV939, a TNKSs-specific inhibitor, protected against ventricular dilatation and cardiac dysfunction and abrogated overactivation of Wnt/β-catenin signaling and dysregulation of miR-34a-5p induced by isoproterenol. Our study unravels a potential role of TNKSs in the pathogenesis of IHF by regulating Wnt/β-catenin signaling and possibly modulating miRNAs and highlights the pharmacotherapeutic potential of TNKS inhibition for prevention of IHF

Human visceral adipose tissue microvascular endothelial cell isolation and establishment of co-culture with white adipocytes to analyze cell-cell communication

Communication between adipocytes and endothelial cells (EC) is suggested to play an important role in the metabolic function of white adipose tissue. In order to generate tools to investigate in detail the physiology and communication of EC and adipocytes, a method for isolation of adipose microvascular EC from visceral adipose tissue (VAT) biopsies of subjects with obesity was developed. Moreover, mature white adipocytes were isolated from the VAT biopsies by a method adapted from a previously published Membrane aggregate adipocytes culture (MAAC) protocol. The identity and functionality of the cultivated and isolated adipose microvascular EC (AMvEC) was validated by imaging their morphology, analyses of mRNA expression, fluorescence activated cell sorting (FACS), immunostaining, low-density lipoprotein (LDL) uptake, and in vitro angiogenesis assays. Finally, we established a new trans filter co-culture system (membrane aggregate adipocyte and endothelial co-culture, MAAECC) for the analysis of communication between the two cell types. EC-adipocyte communication in this system was validated by omics analyses, revealing several altered proteins belonging to pathways such as metabolism, intracellular transport and signal transduction in adipocytes co-cultured with AMvEC. In reverse experiments, induction of several pathways including endothelial development and functions was found in AMvEC co-cultured with adipocytes. In conclusion, we developed a robust method to isolate EC from small quantities of human VAT. Furthermore, the MAAECC system established during the study enables one to study the communication between primary white adipocytes and EC or vice-versa and could also be employed for drug screening