Browsing by Subject "TRANSGENIC MICE"

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  • Brakenhielm, Ebba; Alitalo, Kari (2019)
    The lymphatic vasculature, which accompanies the blood vasculature in most organs, is indispensable in the maintenance of tissue fluid homeostasis, immune cell trafficking, and nutritional lipid uptake and transport, as well as in reverse cholesterol transport. In this Review, we discuss the physiological role of the lymphatic system in the heart in the maintenance of cardiac health and describe alterations in lymphatic structure and function that occur in cardiovascular pathology, including atherosclerosis and myocardial infarction. We also briefly discuss the role that immune cells might have in the regulation of lymphatic growth (lymphangiogenesis) and function. Finally, we provide examples of how the cardiac lymphatics can be targeted therapeutically to restore lymphatic drainage in the heart to limit myocardial oedema and chronic inflammation.
  • Kulesskaya, Natalia; Voikar, Vootele; Peltola, Marjaana; Yegutkin, Gennady G.; Salmi, Marko; Jalkanen, Sirpa; Rauvala, Heikki (2013)
  • Tervaniemi, Mari H.; Siitonen, H. Annika; Soderhall, Cilla; Minhas, Gurinder; Vuola, Jyrki; Tiala, Erica Inkeri; Sormunen, Raija; Samuelsson, Lena; Suomela, Sari; Kere, Juha; Elomaa, Outi (2012)
  • Stanczuk, Lukas; Martinez-Corral, Ines; Ulvmar, Maria H.; Zhang, Yang; Lavina, Barbbara; Fruttiger, Marcus; Adams, Ralf H.; Saur, Dieter; Betsholtz, Christer; Ortega, Sagrario; Alitalo, Kari; Graupera, Mariona; Makinen, Taija (2015)
  • Beck-Nielsen, Signe Sparre; Mughal, Zulf; Haffner, Dieter; Nilsson, Ola; Levtchenko, Elena; Ariceta, Gema; Collantes, Carmen de Lucas; Schnabel, Dirk; Jandhyala, Ravi; Mäkitie, Outi (2019)
    Background: X-linked hypophosphatemia (XLH) is an inherited disease of phosphate metabolism in which inactivating mutations of the Phosphate Regulating Endopeptidase Homolog, X-Linked (PHEX) gene lead to local and systemic effects including impaired growth, rickets, osteomalacia, bone abnormalities, bone pain, spontaneous dental abscesses, hearing difficulties, enthesopathy, osteoarthritis, and muscular dysfunction. Patients with XLH present with elevated levels of fibroblast growth factor 23 (FGF23), which is thought to mediate many of the aforementioned manifestations of the disease. Elevated FGF23 has also been observed in many other diseases of hypophosphatemia, and a range of animal models have been developed to study these diseases, yet the role of FGF23 in the pathophysiology of XLH is incompletely understood. Methods: The role of FGF23 in the pathophysiology of XLH is here reviewed by describing what is known about phenotypes associated with various PHEX mutations, animal models of XLH, and non-nutritional diseases of hypophosphatemia, and by presenting molecular pathways that have been proposed to contribute to manifestations of XLH. Results: The pathophysiology of XLH is complex, involving a range of molecular pathways that variously contribute to different manifestations of the disease. Hypophosphatemia due to elevated FGF23 is the most obvious contributor, however localised fluctuations in tissue non-specific alkaline phosphatase (TNAP), pyrophosphate, calcitriol and direct effects of FGF23 have been observed to be associated with certain manifestations. Conclusions: By describing what is known about these pathways, this review highlights key areas for future research that would contribute to the understanding and clinical treatment of non-nutritional diseases of hypophosphatemia, particularly XLH.
  • Salo, Perttu P.; Havulinna, Aki S.; Tukiainen, Taru; Raitakari, Olli; Lehtimäki, Terho; Kähönen, Mika; Kettunen, Johannes; Männikkö, Minna; Eriksson, Johan G.; Jula, Antti; Blankenberg, Stefan; Zeller, Tanja; Salomaa, Veikko; Kristiansson, Kati; Perola, Markus (2017)
    Background Cardiomyocytes secrete atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in response to mechanical stretching, making them useful clinical biomarkers of cardiac stress. Both human and animal studies indicate a role for ANP as a regulator of blood pressure with conflicting results for BNP. Methods and Results We used genome-wide association analysis (n=6296) to study the effects of genetic variants on circulating natriuretic peptide concentrations and compared the impact of natriuretic peptide-associated genetic variants on blood pressure (n=27059). Eight independent genetic variants in 2 known (NPPA-NPPB and POC1B-GALNT4) and 1 novel locus (PPP3CC) associated with midregional proANP (MR-proANP), BNP, aminoterminal proBNP (NT-proBNP), or BNP:NT-proBNP ratio. The NPPA-NPPB locus containing the adjacent genes encoding ANP and BNP harbored 4 independent cis variants with effects specific to either midregional proANP or BNP and a rare missense single nucleotide polymorphism in NT-proBNP seriously altering its measurement. Variants near the calcineurin catalytic subunit gamma gene PPP3CC and the polypeptide N-acetylgalactosaminyltransferase 4 gene GALNT4 associated with BNP:NT-proBNP ratio but not with BNP or midregional proANP, suggesting effects on the post-translational regulation of proBNP. Out of the 8 individual variants, only those correlated with midregional proANP had a statistically significant albeit weak impact on blood pressure. The combined effect of these 3 single nucleotide polymorphisms also associated with hypertension risk (P=8.2x10(-4)). Conclusions Common genetic differences affecting the circulating concentration of ANP associated with blood pressure, whereas those affecting BNP did not, highlighting the blood pressure-lowering effect of ANP in the general population.
  • Koli, Katri; Sutinen, Eva; Ronty, Mikko; Rantakari, Pia; Fortino, Vittorio; Pulkkinen, Ville; Greco, Dario; Sipila, Petra; Myllarniemi, Marjukka (2016)
    Idiopathic pulmonary fibrosis (IPF) is characterized by activation and injury of epithelial cells, the accumulation of connective tissue and changes in the inflammatory microenvironment. The bone morphogenetic protein (BMP) inhibitor protein gremlin-1 is associated with the progression of fibrosis both in human and mouse lung. We generated a transgenic mouse model expressing gremlin-1 in type II lung epithelial cells using the surfactant protein C (SPC) promoter and the Cre-LoxP system. Gremlin-1 protein expression was detected specifically in the lung after birth and did not result in any signs of respiratory insufficiency. Exposure to silicon dioxide resulted in reduced amounts of lymphocyte aggregates in transgenic lungs while no alteration in the fibrotic response was observed. Microarray gene expression profiling and analyses of bronchoalveolar lavage fluid cytokines indicated a reduced lymphocytic response and a downregulation of interferon-induced gene program. Consistent with reduced Th1 response, there was a downregulation of the mRNA and protein expression of the anti-fibrotic chemokine CXCL10, which has been linked to IPF. In human IPF patient samples we also established a strong negative correlation in the mRNA expression levels of gremlin-1 and CXCL10. Our results suggest that in addition to regulation of epithelial-mesenchymal crosstalk during tissue injury, gremlin-1 modulates inflammatory cell recruitment and anti-fibrotic chemokine production in the lung.
  • Zhang, Yan; Ulvmar, Maria H.; Stanczuk, Lukas; Martinez-Corral, Ines; Frye, Maike; Alitalo, Kari; Mäkinen, Taija (2018)
    Incomplete delivery to the target cells is an obstacle for successful gene therapy approaches. Here we show unexpected effects of incomplete targeting, by demonstrating how heterogeneous inhibition of a growth promoting signaling pathway promotes tissue hyperplasia. We studied the function of the lymphangiogenic VEGFR3 receptor during embryonic and postnatal development. Inducible genetic deletion of Vegfr3 in lymphatic endothelial cells (LECs) leads to selection of non-targeted VEGFR3(+) cells at vessel tips, indicating an indispensable cell-autonomous function in migrating tip cells. Although Vegfr3 deletion results in lymphatic hypoplasia in mouse embryos, incomplete deletion during post-natal development instead causes excessive lymphangiogenesis. Analysis of mosaically targeted endothelium shows that VEGFR3(-) LECs non-cell-autonomously drive abnormal vessel anastomosis and hyperplasia by inducing proliferation of non-targeted VEGFR3(+) LECs through cell-contactdependent reduction of Notch signaling. Heterogeneity in VEGFR3 levels thus drives vessel hyperplasia, which has implications for the understanding of mechanisms of developmental and pathological tissue growth.
  • Meuwissen, Pieter J.; Stolp, Bettina; Iannucci, Veronica; Vermeire, Jolien; Naessens, Evelien; Saksela, Kalle; Geyer, Matthias; Vanham, Guido; Arien, Kevin K.; Fackler, Oliver T.; Verhasselt, Bruno (2012)
  • Khurana, Vikram; Elson-Schwab, Ilan; Fulga, Tudor A.; Sharp, Katherine A.; Loewen, Carin A.; Mulkearns, Erin; Tyynelä, Jaana; Scherzer, Clemens R.; Feany, Mel B. (2010)
  • Leivonen, Suvi-Katri; Icay, Katherine; Jäntti, Kirsi; Siren, Ilari; Liu, Chengyu; Alkodsi, Amjad; Cervera, Alejandra; Ludvigsen, Maja; Hamilton-Dutoit, Stephen Jacques; d'Amore, Francesco; Karjalainen-Lindsberg, Marja-Liisa; Delabie, Jan; Holte, Harald; Lehtonen, Rainer; Hautaniemi, Sampsa; Leppä, Sirpa (2017)
    Despite better therapeutic options and improved survival of diffuse large B-cell lymphoma (DLBCL), 30-40% of the patients experience relapse or have primary refractory disease with a dismal prognosis. To identify biological correlates for treatment resistance, we profiled microRNAs (miRNAs) of matched primary and relapsed DLBCL by next-generation sequencing. Altogether 492 miRNAs were expressed in the DLBCL samples. Thirteen miRNAs showed significant differential expression between primary and relapse specimen pairs. Integration of the differentially expressed miRNAs with matched mRNA expression profiles identified highly anti-correlated, putative targets, which were significantly enriched in cancer-associated pathways, including phosphatidylinositol (PI)), mitogen-activated protein kinase (MAPK), and B-cell receptor (BCR) signaling. Expression data suggested activation of these pathways during disease progression, and functional analyses validated that miR-370-3p, miR-381-3p, and miR-409-3p downregulate genes on the PI, MAPK, and BCR signaling pathways, and enhance chemosensitivity of DLBCL cells in vitro. High expression of selected target genes, that is, PIP5K1 and IMPA1, was found to be associated with poor survival in two independent cohorts of chemoimmunotherapy-treated patients (n = 92 and n = 233). Taken together, our results demonstrate that differentially expressed miRNAs contribute to disease progression by regulating key cell survival pathways and by mediating chemosensitivity, thus representing potential novel therapeutic targets.
  • Haikala, Heidi M.; Klefstrom, Juha; Eilers, Martin; Wiese, Katrin E. (2016)
    Apoptosis caused by deregulated MYC expression is a prototype example of intrinsic tumor suppression. However, it is still unclear how supraphysiological MYC expression levels engage specific sets of target genes to promote apoptosis. Recently, we demonstrated that repression of SRF target genes by MYC/MIZ1 complexes limits AKT-dependent survival signaling and contributes to apoptosis induction. Here we report that supraphysiological levels of MYC repress gene sets that include markers of basal-like breast cancer cells, but not luminal cancer cells, in a MIZ1-dependent manner. Furthermore, repressed genes are part of a conserved gene signature characterizing the basal subpopulation of both murine and human mammary gland. These repressed genes play a role in epithelium and mammary gland development and overlap with genes mediating cell adhesion and extracellular matrix organization. Strikingly, acute activation of oncogenic MYC in basal mammary epithelial cells is sufficient to induce luminal cell identity markers. We propose that supraphysiological MYC expression impacts on mammary epithelial cell identity by repressing lineage-specific target genes. Such abrupt cell identity switch could interfere with adhesion-dependent survival signaling and thus promote apoptosis in pre-malignant epithelial tissue.
  • Redchuk, Taras A.; Kaberniuk, Andrii A.; Verkhusha, Vladislav V. (2018)
    Near-infrared (NIR, 740-780 nm) optogenetic systems are well-suited to spectral multiplexing with blue-light-controlled tools. Here, we present two protocols, one for regulation of gene transcription and another for control of protein localization, that use a NIR-responsive bacterial phytochrome BphP1-QPAS1 optogenetic pair. In the first protocol, cells are transfected with the optogenetic constructs for independently controlling gene transcription by NIR (BphP1-QPAS1) and blue (LightOn) light. The NIR and blue-light-controlled gene transcription systems show minimal spectral crosstalk and induce a 35- to 40-fold increase in reporter gene expression. In the second protocol, the BphP1-QPAS1 pair is combined with a light-oxygen-voltage-sensing (LOV) domain-based construct into a single optogenetic tool, termed iRIS. This dual-light-controllable protein localization tool allows tridirectional protein translocation among the cytoplasm, nucleus and plasma membrane. Both procedures can be performed within 3-5 d. Use of NIR light-controlled optogenetic systems should advance basic and biomedical research.
  • Yatkin, Emrah; Polari, Lauri; Laajala, Teemu D.; Smeds, Annika; Eckerman, Christer; Holmbom, Bjarne; Saarinen, Niina M.; Aittokallio, Tero; Makela, Sari I. (2014)
  • Azevedo, Cláudia; Pinto, Soraia; Benjakul, Sopisa; Nilsen, Jeannette; Santos, Hélder A.; Traverso, Giovanni; Andersen, Jan Terje; Sarmento, Bruno (2021)
    Diabetes mellitus is a chronic disease with an elevated risk of micro- and macrovascular complications, such as fibrosis. To prevent diabetes-associated fibrosis, the symptomatology of diabetes must be controlled, which is commonly done by subcutaneous injection of antidiabetic peptides. To minimize the pain and distress associated with such injections, there is an urgent need for non-invasive oral transmucosal drug delivery strategies. However, orally administered peptide-based drugs are exposed to harsh conditions in the gastrointestinal tract and poorly cross the selective intestinal epithelium. Thus, targeting of drugs to receptors expressed in epithelial cells, such as the neonatal Fc receptor (FcRn), may therefore enhance uptake and transport through mucosal barriers. This review compiles how in-depth studies of FcRn biology and engineering of receptor-binding molecules may pave the way for design of new classes of FcRn-targeted nanosystems. Tailored strategies may open new avenues for oral drug delivery and provide better treatment options for diabetes and, consequently, fibrosis prevention.
  • Van Nuffel, Anouk; Arien, Kevin K.; Stove, Veronique; Schindler, Michael; O'Neill, Eduardo; Schmoekel, Jan; Van de Walle, Inge; Naessens, Evelien; Vanderstraeten, Hanne; Van Landeghem, Kathleen; Taghon, Tom; Pulkkinen, Kati; Saksela, Kalle; Garcia, J. Victor; Fackler, Oliver T.; Kirchhoff, Frank; Verhasselt, Bruno (2013)
  • Sarajärvi, T.; Jäntti, M.; Paldanius, K. M. A.; Natunen, T.; Wu, J. C.; Mäkinen, P.; Tarvainen, I.; Tuominen, R. K.; Talman, V.; Hiltunen, M. (2018)
    Abnormal protein kinase C (PKC) function contributes to many pathophysiological processes relevant for Alzheimer's disease (AD), such as amyloid precursor protein (APP) processing. Phorbol esters and other PKC activators have been demonstrated to enhance the secretion of soluble APP alpha (sAPP alpha), reduce the levels of beta-amyloid (A beta), induce synaptogenesis, and promote neuroprotection. We have previously described isophthalate derivatives as a structurally simple family of PKC activators. Here, we characterised the effects of isophthalate derivatives HMI-1a3 and HMI-1b11 on neuronal viability, neuroinflammatory response, processing of APP and dendritic spine density and morphology in in vitro. HMI-1a3 increased the viability of embryonic primary cortical neurons and decreased the production of the pro-inflammatory mediator TNF alpha, but not that of nitric oxide, in mouse neuron-BV2 microglia co-cultures upon LPS- and IFN-gamma-induced neuroinflammation. Furthermore, both HMI-1a3 and HMI-1b11 increased the levels of sAPPa relative to total sAPP and the ratio of A beta 42/A beta 40 in human SH-Sv5v neuroblastoma cells. Finally, bryostatin-1, but not HMI-1a3, increased the number of mushroom spines in proportion to total spine density in mature mouse hippocampal neuron cultures. These results suggest that the PKC activator HMI-1a3 exerts neuroprotective functions in the in vitro models relevant for AD by reducing the production of TNF alpha and increasing the secretion of neuroprotective sAPPa.
  • Leppä, Elli; Linden, Anni-Maija; Vekovischeva, Olga Y.; Swinny, Jerome D.; Rantanen, Ville; Toppila, Esko; Hoeger, Harald; Sieghart, Werner; Wulff, Peer; Wisden, William; Korpi, Esa R. (2011)
  • Albert, Katrina; Niskanen, Jonna; Kälvälä, Sara; Lehtonen, Šárka (2021)
    Induced pluripotent stem cells (iPSCs) are a self-renewable pool of cells derived from an organism’s somatic cells. These can then be programmed to other cell types, including neurons. Use of iPSCs in research has been two-fold as they have been used for human disease modelling as well as for the possibility to generate new therapies. Particularly in complex human diseases, such as neurodegenerative diseases, iPSCs can give advantages over traditional animal models in that they more accurately represent the human genome. Additionally, patient-derived cells can be modified using gene editing technology and further transplanted to the brain. Glial cells have recently become important avenues of research in the field of neurodegenerative diseases, for example, in Alzheimer’s disease and Parkinson’s disease. This review focuses on using glial cells (astrocytes, microglia, and oligodendrocytes) derived from human iPSCs in order to give a better understanding of how these cells contribute to neurodegenerative disease pathology. Using glia iPSCs in in vitro cell culture, cerebral organoids, and intracranial transplantation may give us future insight into both more accurate models and disease-modifying therapies.
  • Hominickn, Devon; Silva, Asitha; Khurana, Noor; Liu, Ying; Dechow, Paul C.; Feng, Jian Q.; Pytowski, Bronislaw; Rutkowski, Joseph M.; Alitalo, Kari; Dellinger, Michael T. (2018)
    Patients with Gorham-Stout disease (GSD) have lymphatic vessels in their bones and their bones gradually disappear. Here, we report that mice that overexpress VEGF-C in bone exhibit a phenotype that resembles GSD. To drive VEGF-C expression in bone, we generated Osx-tTA; TetO-Vegfc double-transgenic mice. In contrast to Osx-tTA mice, Osx-tTA; TetO-Vegfc mice developed lymphatics in their bones. We found that inhibition of VEGFR3, but not VEGFR2, prevented the formation of bone lymphatics in Osx-tTA; TetO-Vegfc mice. Radiological and histological analysis revealed that bones from Osx-tTA; TetO-Vegfc mice were more porous and had more osteoclasts than bones from Osx-tTA mice. Importantly, we found that bone loss in Osx-tTA; TetO-Vegfc mice could be attenuated by an osteoclast inhibitor. We also discovered that the mutant phenotype of Osx-tTA; TetO-Vegfc mice could be reversed by inhibiting the expression of VEGF-C. Taken together, our results indicate that expression of VEGF-C in bone is sufficient to induce the pathologic hallmarks of GSD in mice.