Pukkiselän Natura 2000 –alueen hoitosuunnitelma

Kangasniemellä sijaitseva Pukkiselkä kuuluu sekä valtakunnalliseen lintuvesiensuojeluohjelmaan että Natura 2000 –verkostoon. Pukkiselkää luonnehtivat laajat korte- ja saravaltaiset luhdat, eteläosassa sijaitseva 10 hehtaarin kokoinen avovesialue sekä maisemaa jakavat metsäiset saaret. Järven vesilinnustoa uhkaa varsin nopeasti etenevä vesialueen umpeenkasvu, jonka syinä ovat olleet vesialueen mataluus sekä valuma-alueelta järveen päätynyt suuri kiintoaine- ja ravinnekuormitus. Etelä-Savon ympäristökeskuksen laatimassa Etelä-Savon Natura 2000 –verkoston hoidon ja käytön yleissuunnitelmassa Pukkiselkä luokiteltiinkin kohteeksi, jolla on kiireellinen hoitosuunnittelun tarve. Nyt valmistuneessa hoitosuunnitelmassa lintuvesialueelle esitetään ruoppauksia, joihin sisältyy sekä väylien että laajempien lampareiden tekeminen. Hoitosuunnitelma on laadittu yhteistyössä alueen maanomistajien, osakaskuntien ja sidosryhmien kanssa. Hoidon suunnittelussa ovat pääpainona olleet linnustonsuojelulliset arvot, mutta mahdollisuuksien mukaan on pyritty ottamaan huomioon myös järven virkistyskäyttön tarpeita

Putkilahti-Ruskeanperän Natura 2000 -alueen hoitosuunnitelma

Etelä-Savon keskiosassa Rantasalmella sijaitseva Putkilahti-Ruskeanperä on luonnonarvoiltaan merkittävä järvi- ja kosteikkokokonaisuus. Putkilahti-Ruskeanperä on valtakunnallisessa lintuvesiensuojeluohjelmassa kansainvälisesti arvokkaana kohteena ja järven ympärillä olevat laajat suoalueet kuuluvat soidensuojelun perusohjelmaan. Alueella on myös tunnustettu olevan kansainvälistä merkitystä, koska Rantasalmen lintuvedet kuuluvat Suomen Ramsar-alueisiin. Putkilahti-Ruskeanperä kuuluu Natura 2000 -verkostoon sekä lintudirektiivin mukaisena SPA-alueena että luontodirektiivin tarkoittamana SCI-alueena. Putkilahti-Ruskeanperä on mataluutensa ja rehevyytensä puolesta tyypillinen lintuvesi. Tietyin osin järveä uhkaa ruovikoitumisen ja umpeenkasvun aiheuttama luonnonsuojeluarvon ja linnustollisen merkityksen heikentyminen. Alueen hoito toteutetaan niitoin ja rakentamalla pohjapato Puikonkoskeen, jolle haetaan vesioikeudellista lupaa vuonna 2007. Niitot toteutetaan vuosina 2007-2009 ja niitot kohdistuvat Putkilahden pohjoisosan järviruovikoihin. Niitettävien alueiden pinta-ala on noin 5 hehtaaria. Pohjapadon rakentamisella nostetaan Putkilahti-Ruskeanperän alivedenkorkeutta 20-30 cm. Alivedenkorkeuden nostolla tavoitellaan umpeenkasvun hidastumista heikentämällä matalien alueiden ruovikoitumista ja saraluhtien levittäytymistä avovettä kohti. Avoimien rantojen lisääntyminen parantaisi monien vesilintujen ja kahlaajien tilannetta. Toisaalta alivedenkorkeuden nostaminen hidastanee ranta-alueiden ja avosoiden pensoittumista ja puustottumista. Hoitotoimien vaikuttavuutta arvioidaan linnustoseurantojen, kasvillisuusselvityksen ja vedenlaadun seurannan avulla vertaamalla hoidon jälkeistä tilannetta hoitoa edeltäneeseen tilanteeseen

EGFR Signaling Promotes beta-Cell Proliferation and Survivin Expression during Pregnancy

Placental lactogen (PL) induced serotonergic signaling is essential for gestational beta-cell mass expansion. We have previously shown that intact Epidermal growth factor -receptor (EGFR) function is a crucial component of this pathway. We now explored more specifically the link between EGFR and pregnancy-induced beta-cell mass compensation. Islets were isolated from wild-type and beta-cell-specific EGFR-dominant negative mice (E1-DN), stimulated with PL and analyzed for beta-cell proliferation and expression of genes involved in gestational beta-cell growth. beta-cell mass dynamics were analyzed both with traditional morphometrical methods and three dimensional optical projection tomography (OPT) of whole-mount insulin-stained pancreata. Insulin-positive volume analyzed with OPT increased 1.4-fold at gestational day 18.5 (GD18.5) when compared to non-pregnant mice. Number of islets peaked by GD13.5 (680 vs 1134 islets per pancreas, non-pregnant vs. GD13.5). PL stimulated beta cell proliferation in the wild-type islets, whereas the proliferative response was absent in the E1-DN mouse islets. Serotonin synthesizing enzymes were upregulated similarly in both the wild-type and E1-DN mice. However, while survivin (Birc5) mRNA was upregulated 5.5-fold during pregnancy in the wild-type islets, no change was seen in the E1-DN pregnant islets. PL induced survivin expression also in isolated islets and this was blocked by EGFR inhibitor gefitinib, mTOR inhibitor rapamycin and MEK inhibitor PD0325901. Our 3D-volumetric analysis of beta-cell mass expansion during murine pregnancy revealed that islet number increases during pregnancy. In addition, our results suggest that EGFR signaling is required for lactogen-induced survivin expression via MAPK and mTOR pathways.Peer reviewe

sept7b is required for the differentiation of pancreatic endocrine progenitors

Protection or restoration of pancreatic beta-cell mass as a therapeutic treatment for type 1 diabetes requires understanding of the mechanisms that drive the specification and development of pancreatic endocrine cells. Septins are filamentous small GTPases that function in the regulation of cell division, cytoskeletal organization and membrane remodeling, and are involved in various tissue-specific developmental processes. However, their role in pancreatic endocrine cell differentiation remains unknown. Here we show by functional manipulation techniques in transgenic zebrafish lines that suppression of sept7b, the zebrafish ortholog of human SEPT7, profoundly increases the number of endocrine progenitors but limits their differentiation, leading to reduction in beta- and alpha-cell mass. Furthermore, we discovered that shh (sonic hedgehog) expression in the endoderm, essential for the development of pancreatic progenitors of the dorsal pancreatic bud, is absent in larvae depleted of sept7b. We also discovered that sept7b is important for the differentiation of ventral pancreatic bud-derived cells: sept7b-depleted larvae exhibit downregulation of Notch receptors notch1a and notch1b and show precocious differentiation of NeuroD-positive endocrine cells in the intrapancreatic duct and gut epithelium. Collectively, this study provides a novel insight into the development of pancreatic endocrine progenitors, revealing an essential role for sept7b in endocrine progenitor differentiation.Peer reviewe

Cytomegalovirus infection of human kidney cells in vitro

Cytomegalovirus infection of human kidney cells in vitro. To study which structures of a kidney allograft are the main targets for cytomegalovirus (CMV), human glomerular epithelial and mesangial cells, as well as tubular epithelial and endothelial cells were isolated by steel meshes of different pore sizes and enzymatic treatments. The various cultured cell types were characterized by morphology and specific antibodies. Human CMV was inoculated onto cell monolayers using two different culture methods: conventional tissue culture and rapid shell vial culture. To analyze whether CMV had a direct effect on the immunologic properties of kidney parenchymal cells, MHC class I and class II antigen expression was estimated before and after the infection. CMV infected all kidney cells identically. All cells expressed class I strongly after the infection, but they were class I positive prior to infection. Class II antigens were not expressed on the cell surface either before or after the infection. In conclusion, human kidney cells of glomerular, tubular and vascular origin were all infected by CMV without any difference. CMV had no significant direct effects on the antigenic properties of the cells

Distinct differentiation characteristics of individual human embryonic stem cell lines

BACKGROUND: Individual differences between human embryonic stem cell (hESC) lines are poorly understood. Here, we describe the derivation of five hESC lines (called FES 21, 22, 29, 30 and 61) from frozen-thawed human embryos and compare their individual differentiation characteristic. RESULTS: The cell lines were cultured either on human or mouse feeder cells. The cells grew significantly faster and could be passaged enzymatically only on mouse feeders. However, this was found to lead to chromosomal instability after prolonged culture. All hESC lines expressed the established markers of pluripotent cells as well as several primordial germ cell (PGC) marker genes in a uniform manner. However, the cell lines showed distinct features in their spontaneous differentiation patterns. The embryoid body (EB) formation frequency of FES 30 cell line was significantly lower than that of other lines and cells within the EBs differentiated less readily. Likewise, teratomas derived from FES 30 cells were constantly cystic and showed only minor solid tissue formation with a monotonous differentiation pattern as compared with the other lines. CONCLUSION: hESC lines may differ substantially in their differentiation properties although they appear similar in the undifferentiated state

A Novel Feeder-Free Culture System for Human Pluripotent Stem Cell Culture and Induced Pluripotent Stem Cell Derivation

Peer reviewe

Early-Onset Diabetic E1-DN Mice Develop Albuminuria and Glomerular Injury Typical of Diabetic Nephropathy

The transgenic E1-DN mice express a kinase-negative epidermal growth factor receptor in their pancreatic islets and are diabetic from two weeks of age due to impaired postnatal growth of beta-cell mass. Here, we characterize the development of hyperglycaemia-induced renal injury in the E1-DN mice. Homozygous mice showed increased albumin excretion rate (AER) at the age of 10 weeks; the albuminuria increased over time and correlated with blood glucose. Morphometric analysis of PAS-stained histological sections and electron microscopy images revealed mesangial expansion in homozygous E1-DN mice, and glomerular sclerosis was observed in the most hyperglycaemic mice. The albuminuric homozygous mice developed also other structural changes in the glomeruli, including thickening of the glomerular basement membrane and widening of podocyte foot processes that are typical for diabetic nephropathy. Increased apoptosis of podocytes was identified as one mechanism contributing to glomerular injury. In addition, nephrin expression was reduced in the podocytes of albuminuric homozygous E1-DN mice. Tubular changes included altered epithelial cell morphology and increased proliferation. In conclusion, hyperglycaemic E1-DN mice develop albuminuria and glomerular and tubular injury typical of human diabetic nephropathy and can serve as a new model to study the mechanisms leading to the development of diabetic nephropathy.Peer reviewe

An Activating STAT3 Mutation Causes Neonatal Diabetes through Premature Induction of Pancreatic Differentiation

Activating germline mutations in STAT3 were recently identified as a cause of neonatal diabetes mellitus associated with beta-cell autoimmunity. We have investigated the effect of an activating mutation, STAT3(K392R,) on pancreatic development using induced pluripotent stem cells (iPSCs) derived from a patient with neonatal diabetes and pancreatic hypoplasia. Early pancreatic endoderm differentiated similarly from STAT3(K392R) and healthy-control cells, but in later stages, NEUROG3 expressionwas upregulated prematurely in STAT3(K392R) cells together with insulin (INS) and glucagon (GCG). RNA sequencing (RNA-seq) showed robust NEUROG3 downstream targets upregulation. STAT3 mutation correction with CRISPR/Cas9 reversed completely the disease phenotype. STAT3(K392R) -activating properties were not explained fully by altered DNA-binding affinity or increased phosphorylation. Instead, reporter assays demonstrated NEUROG3 promoter activation by STAT3 in pancreatic cells. Furthermore, proteomic and immunocytochemical analyses revealed increased nuclear translocation of STAT3(K392R). Collectively, our results demonstrate that the STAT3(K392R) mutation causes premature endocrine differentiation through direct induction of NEUROG3 expression.Peer reviewe

MANF is indispensable for the proliferation and survival of pancreatic beta-cells

All forms of diabetes mellitus (DM) are characterized by the loss of functional pancreatic β cell mass, leading to insufficient insulin secretion. Thus, identification of novel approaches to protect and restore β cells is essential for the development of DM therapies. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER)-stress-inducible protein, but its physiological role in mammals has remained obscure. We generated MANF-deficient mice that strikingly develop severe diabetes due to progressive postnatal reduction of β cell mass, caused by decreased proliferation and increased apoptosis. Additionally, we show that lack of MANF in vivo in mouse leads to chronic unfolded protein response (UPR) activation in pancreatic islets. Importantly, MANF protein enhanced β cell proliferation in vitro and overexpression of MANF in the pancreas of diabetic mice enhanced β cell regeneration. We demonstrate that MANF specifically promotes β cell proliferation and survival, thereby constituting a therapeutic candidate for β cell protection and regeneration.Peer reviewe