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1.	Cai, Huan, et al. (author) Critical role of Lama4 for hematopoiesis regeneration and acute myeloid leukemia progression 2022 In: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 139:20, s. 3040-3057 Journal article (peer-reviewed)abstract Impairment of normal hematopoiesis and leukemia progression are 2 well-linked processes during leukemia development and are controlled by the bone marrow (BM) niche. Extracellular matrix proteins, including laminin, are important BM niche components. However, their role in hematopoiesis regeneration and leukemia is unknown. Laminin α4 (Lama4), a major receptor-binding chain of several laminins, is altered in BM niches in mice with acute myeloid leukemia (AML). So far, the impact of Lama4 on leukemia progression remains unknown. We here report that Lama4 deletion in mice resulted in impaired hematopoiesis regeneration following irradiation-induced stress, which is accompanied by altered BM niche composition and inflammation. Importantly, in a transplantation-induced MLL-AF9 AML mouse model, we demonstrate accelerated AML progression and relapse in Lama4−/− mice. Upon AML exposure, Lama4−/− mesenchymal stem cells (MSCs) exhibited dramatic molecular alterations, including upregulation of inflammatory cytokines that favor AML growth. Lama4−/− MSCs displayed increased antioxidant activities and promoted AML stem cell proliferation and chemoresistance to cytarabine, which was accompanied by increased mitochondrial transfer from the MSCs to AML cells and reduced reactive oxygen species in AML cells in vitro. Similarly, we detected lower levels of reactive oxygen species in AML cells from Lama4−/− mice post–cytarabine treatment. Notably, LAMA4 inhibition or knockdown in human MSCs promoted human AML cell proliferation and chemoprotection. Together, our study for the first time demonstrates the critical role of Lama4 in impeding AML progression and chemoresistance. Targeting Lama4 signaling pathways may offer potential new therapeutic options for AML.
2.	Chen, Yunying, et al. (author) A regulatory role for macrophage class A scavenger receptors in TLR4-mediated LPS responses. 2010 In: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 40:5, s. 1451-60 Journal article (peer-reviewed)abstract Recognition of microbial components by TLR, key sensors of infection, leads to induction of inflammatory responses. We found that, in vivo, TLR4 engagement by LPS induces up-regulation of the class A scavenger receptors (SR) macrophage receptor with a collagenous structure (MARCO) and SR-A, which occurs, at least in the case of MARCO, via both MyD88-dependent and -independent pathways. When challenging mice with a low dose of LPS followed by a high dose, class A SR-deficient mice showed a higher survival rate than WT mice. This was paired with increased production of IL-10 and anti-LPS Ab, as well as increased activation status of marginal zone B cells. However, the receptors were not crucial for survival when challenging mice i.p. with Neisseria meningitidis or Listeria monocytogenes, but they were found to contribute to microbial capture and clearance. This indicates physiological significance for the up-regulation of class A SR during early stages of bacterial infection. Thus, we believe that we have revealed a mechanism where SR regulate the activation status of the immune system and are involved in balancing a proper immune response to infection. This regulation could also be important in maintaining tolerance since these receptors have been shown to be involved in regulation of self-reactivity.
3.	Damdimopoulou, Pauliina, et al. (author) Human embryonic stem cells 2016 In: Baillière's Best Practice & Research. - : Elsevier BV. - 1521-6934 .- 1532-1932. ; 31, s. 2-12 Journal article (peer-reviewed)abstract The establishment of permanent human embryonic stem cell lines (hESCs) was first reported in 1998. Due to their pluripotent nature and ability to differentiate to all cell types in the body, they have been considered as a cell source for regenerative medicine. Since then, intensive studies have been carried out regarding factors regulating pluripotency and differentiation. hESCs are obtained from supernumerary human IVF (in vitro fertilization) embryos that cannot be used for the couple's infertility treatment. Today, we can establish and expand these cells in animal substance-free conditions, even from single cells biopsied from eight-cell stage embryos. There are satisfactory tests for the demonstration of genetic stability, absence of tumorigenic mutations, functionality, and safety of hESCs. Clinical trials are ongoing for age-related macular degeneration (AMD) and spinal cord injury (SCI). This review focuses on the present state of these techniques.
4.	Dunér, Fredrik, et al. (author) Permeability, ultrastructural changes, and distribution of novel proteins in the glomerular barrier in early puromycin aminonucleoside nephrosis. 2010 In: Nephron. Experimental nephrology. - : S. Karger AG. - 1660-2129. ; 116:2 Journal article (peer-reviewed)abstract BACKGROUND/AIMS: It is still unclear what happens in the glomerulus when proteinuria starts. Using puromycin aminonucleoside nephrosis (PAN) rats, we studied early ultrastructural and permeability changes in relation to the expression of the podocyte-associated molecules nephrin, α-actinin, dendrin, and plekhh2, the last two of which were only recently discovered in podocytes. METHODS: Using immune stainings, semiquantitative measurement was performed under the electron microscope. Permeability was assessed using isolated kidney perfusion with tracers. Possible effects of ACE inhibition were tested. RESULTS: By day 2, some patchy foot process effacement, but no proteinuria, appeared. The amount of nephrin was reduced in both diseased and normal areas. The other proteins showed few changes, which were limited to diseased areas. By day 4, foot process effacement was complete and proteinuria appeared in parallel with signs of size barrier damage. Nephrin decreased further, while dendrin and plekhh2 also decreased but α-actinin remained unchanged. ACE inhibition had no significant protective effect. CONCLUSIONS: PAN glomeruli already showed significant pathology by day 4, despite relatively mild proteinuria. This was preceded by altered nephrin expression, supporting its pivotal role in podocyte morphology. The novel proteins dendrin and plekhh2 were both reduced, suggesting roles in PAN, whereas α-actinin was unchanged.
5.	Gotha, Lara, et al. (author) Heparan sulfate side chains have a critical role in the inhibitory effects of perlecan on vascular smooth muscle cell response to arterial injury 2014 In: American Journal of Physiology: Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 307:3, s. 337-345 Journal article (peer-reviewed)abstract Perlecan is a proteoglycan composed of a 470-kDa core protein linked to three heparan sulfate (HS) glycosaminoglycan chains. The intact proteoglycan inhibits the smooth muscle cell (SMC) response to vascular injury. Hspg2(Delta 3/Delta 3) (M Delta 3/Delta 3) mice produce a mutant perlecan lacking the HS side chains. The objective of this study was to determine differences between these two types of perlecan in modifying SMC activities to the arterial injury response, in order to define the specific role of the HS side chains. In vitro proliferative and migratory activities were compared in SMC isolated from M Delta 3/Delta 3 and wild-type mice. Proliferation of M Delta 3/Delta 3 SMC was 1.5x greater than in wild type (P < 0.001), increased by addition of growth factors, and showed a 42% greater migratory response than wild-type cells to PDGF-BB (P < 0.001). In M Delta 3/Delta 3 SMC adhesion to fibronectin, and collagen types I and IV was significantly greater than wild type. Addition of DRL-12582, an inducer of perlecan expression, decreased proliferation and migratory response to PDGF-BB stimulation in wild-type SMC compared with M Delta 3/Delta 3. In an in vivo carotid artery wire injury model, the medial thickness, medial area/lumen ratio, and macrophage infiltration were significantly increased in the M Delta 3/Delta 3 mice, indicating a prominent role of the HS side chain in limiting vascular injury response. Mutant perlecan that lacks HS side chains had a marked reduction in the inhibition of in vitro SMC function and the in vivo arterial response to injury, indicating the critical role of HS side chains in perlecan function in the vessel wall.
6.	He, Bing, et al. (author) Lmx1b and FoxC Combinatorially Regulate Podocin Expression in Podocytes 2014 In: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 25:12, s. 2764-2777 Journal article (peer-reviewed)abstract Podocin is a key protein of the kidney podocyte slit diaphragm protein complex, an important part of the glomerular filtration barrier. Mutations in the human podocin gene NPHS2 cause familial or sporadic forms of renal disease owing to the disruption of filtration barrier integrity. The exclusive expression of NPHS2 in podocytes reflects its unique function and raises interesting questions about its transcriptional regulation. Here, we further define a 2.5-kb zebrafish nphs2 promoter fragment previously described and identify a 49-bp podocyte-specific transcriptional enhancer using Tol2-mediated G(0) transgenesis in zebrafish. Within this enhancer, we identified a cis-acting element composed of two adjacent DNA-binding sites (FLAT-E and forkhead) bound by transcription factors Lnnx1b and FoxC. In zebrafish, double knockdown of Lmx1b and FoxC orthologs using morpholino doses that caused no or minimal phenotypic changes upon individual knockdown completely disrupted podocyte development in 40% of injected embryos. Co-overexpression of the two genes potently induced endogenous nphs2 expression in zebrafish podocytes. We found that the NPHS2 promoter also contains a cis-acting Lmx1b-FoxC motif that binds LMX1B and FoxC2. Furthermore, a genome-wide search identified several genes that carry the Lmx1b-FoxC motif in their promoter regions. Among these candidates, motif-driven podocyte enhancer activity of CCNC and MEIS2 was functionally analyzed in vivo. Our results show that podocyte expression of some genes is combinatorially regulated by two transcription factors interacting synergistically with a common enhancer. This finding provides insights into transcriptional mechanisms required for normal and pathologic podocyte functions.
7.	He, L, et al. (author) Glomerulus-specific mRNA transcripts and proteins identified through kidney expressed sequence tag database analysis 2007 In: Kidney International. - 1523-1755 .- 0085-2538. ; 71:9, s. 889-900 Journal article (peer-reviewed)abstract The kidney glomerulus plays a crucial role in blood filtration but the molecular composition and physiology of the glomerulus is not well understood. We previously constructed and large-scale sequenced four mouse glomerular expressed sequence tag (EST) libraries from newborn and adult mouse glomeruli. Here, we compared glomerular EST profiles with whole kidney EST profiles, thereby identifying 497 transcripts corresponding to UniGene clusters that were glomerulus-enriched, that is expressed more abundantly in glomeruli than in whole kidney. These include several known protein-coding glomerulus-specific transcripts critical for glomerulus development and function, but also a large number of gene transcripts, which have not previously been shown to be expressed in the glomerulus, or implicated in glomerular functions. We used in situ hybridization to demonstrate glomerulus-specific RNA expression for six novel glomerular genes and the public Human Protein Atlas to verify glomerular protein expression for another two. The higher mRNA abundance for the eight genes in glomeruli compared with whole kidney was also verified by Taqman quantitative polymerase chain reaction. We surmise that the further characterization of these genes and proteins will increase our understanding of glomerular development and physiology.
8.	He, Liqun, et al. (author) The glomerular transcriptome and a predicted protein-protein interaction network 2008 In: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 19:2, s. 260-268 Journal article (peer-reviewed)abstract To increase our understanding of the molecular composition of the kidney glomerulus, we performed a meta-analysis of available glomerular transcriptional profiles made from mouse and man using five different methodologies. We generated a combined catalogue of glomerulus-enriched genes that emerged from these different sources and then used this to construct a predicted protein-protein interaction network in the glomerulus (GlomNet). The combined glomerulus-enriched gene catalogue provides the most comprehensive picture of the molecular composition of the glomerulus currently available, and GlomNet contributes an integrative systems biology approach to the understanding of glomerular signaling networks that operate during development, function, and disease.
9.	Ishikawa, Takahiro, et al. (author) A novel podocyte protein, R3h domain containing-like, inhibits TGF-β-induced p38 MAPK and regulates the structure of podocytes and glomerular basement membrane 2021 In: Journal of Molecular Medicine. - : Springer Science and Business Media LLC. - 0946-2716 .- 1432-1440. ; 99:6, s. 859-876 Journal article (peer-reviewed)abstract Not only in kidney glomerular physiological function but also glomerular pathology especially in diabetic condition, glomerular podocytes play pivotal roles. Therefore, it is important to increase our knowledge about the genes and proteins expressed in podocytes. Recently, we have identified a novel podocyte-expressed gene, R3h domain containing-like (R3hdml) and analyzed its function in vivo as well as in vitro. Transforming growth factor-β (TGF-β) signaling regulated the expression of R3hdml. And R3hdml inhibited p38 mitogen-activated protein kinase phosphorylation, which was induced by TGF-β, leading to the amelioration of podocyte apoptosis. Furthermore, a lack of R3hdml in mice significantly worsened glomerular function in streptozotocin (STZ)-induced diabetes, while overexpression of R3hdml ameliorated albuminuria in STZ-induced diabetes. Our results surmise that the functional analyses of R3hdml may lead to the development of novel therapeutic strategies for diabetic nephropathy in the future.
10.	Jakobsson, Lars, et al. (author) Laminin deposition is dispensable for vasculogenesis but regulates blood vessel diameter independent of flow 2008 In: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 22:5, s. 1530-1539 Journal article (peer-reviewed)abstract Basement membranes (BMs) consisting of laminins, collagens, and heparan sulfate proteoglycans (HSPGs) are vital for proper endothelial cell function, but many aspects of their role in vascular development remain unknown. Here, we demonstrate that vascular structures within differentiating embryoid bodies are wrapped in a BM composed of alpha 4- and alpha 5-chain laminins, fibronectin, collagen IV, and HSPGs. In sprouting angiogenesis, laminins were produced by stalk cells, as well as the leading tip cell, and deposited along the sprout length, including tip cell filopodia. In embryonic stem cells deficient in laminins, due to lamc1 (laminin gamma 1) deletion, vascular development and organization were largely unaffected. However, the frequency of vessels with wide lumens was increased 4-fold. Laminin-deficient vessels were moreover characterized by increased fibronectin levels and enhanced endothelial cell proliferation. We conclude that laminins are dispensable for vascular development but that they regulate lumen formation in the absence of flow and vascular tone.
11.	Jakobsson, Lars, et al. (author) Laminins regulate vascular lumen diameter Journal article (peer-reviewed)
12.	Liu, Xiao Li, et al. (author) Characterization of the interactions of the nephrin intracellular domain 2005 In: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 272:1, s. 228-243 Journal article (peer-reviewed)abstract Nephrin is a signalling cell-cell adhesion protein of the Ig superfamily and the first identified component of the slit diaphragm that forms the critical and ultimate part of the glomerular ultrafiltration barrier. The extracellular domains of the nephrin molecules form a network of homophilic and heterophilic interactions building the structural scaffold of the slit diaphragm between the podocyte foot processes. The intracellular domain of nephrin is connected indirectly to the actin cytoskeleton, is tyrosine phosphorylated, and mediates signalling from the slit diaphragm into the podocytes. CD2AP, podocin, Fyn kinase, and phosphoinositide 3-kinase are reported intracellular interacting partners of nephrin, although the biological roles of these interactions are unclarified. To characterize the structural properties and protein-protein interactions of the nephrin intracellular domain, we produced a series of recombinant nephrin proteins. These were able to bind all previously identified ligands, although the interaction with CD2AP appeared to be of extremely low stoichiometry. Fyn phosphorylated nephrin proteins efficiently in vitro. This phosphorylation was required for the binding of phosphoinositide 3-kinase, and significantly enhanced binding of Fyn itself. A protein of 190 kDa was found to associate with the immobilized glutathione S-transferase-nephrin. Peptide mass fingerprinting and amino acid sequencing identified this protein as IQGAP1, an effector protein of small GTPases Rac1 and Cdc42 and a putative regulator of cell-cell adherens junctions. IQGAP1 is expressed in podocytes at significant levels, and could be found at the immediate vicinity of the slit diaphragm. However, further studies are needed to confirm the biological significance of this interaction and its occurrence in vivo.
13.	Mirastschijski, Ursula, et al. (author) Wound healing in membrane-type-1 matrix metalloproteinase-deficient mice. 2004 In: J Invest Dermatol. - 0022-202X. ; 123, s. 600-602 Journal article (other academic/artistic)
14.	Nishibori, Yukino, et al. (author) Glcci1 Deficiency Leads to Proteinuria 2011 In: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 22:11, s. 2037-2046 Journal article (peer-reviewed)abstract Unbiased transcriptome profiling and functional genomics approaches identified glucocorticoid-induced transcript 1 (GLCCI1) as being a transcript highly specific for the glomerulus, but its role in glomerular development and disease is unknown. Here, we report that mouse glomeruli express far greater amounts of Glcci1 protein compared with the rest of the kidney. RT-PCR and Western blotting demonstrated that mouse glomerular Glcci1 is approximately 60 kD and localizes to the cytoplasm of podocytes in mature glomeruli. In the fetal kidney, intense Glcci1 expression occurs at the capillary-loop stage of glomerular development. Using gene knockdown in zebrafish with morpholinos, morphants lacking Glcci1 function had collapsed glomeruli with foot-process effacement. Permeability studies of the glomerular filtration barrier in these zebrafish morphants demonstrated a disruption of the selective glomerular permeability filter. Taken together, these data suggest that Glcci1 promotes the normal development and maintenance of podocyte structure and function.
15.	Patrakka, Jaakko, et al. (author) Expression and subcellular distribution of novel glomerulus-associated proteins dendrin, ehd3, sh2d4a, plekhh2, and 2310066E14Rik 2007 In: Journal of the American Society of Nephrology. - : Ovid Technologies (Wolters Kluwer Health). - 1046-6673 .- 1533-3450. ; 18:3, s. 689-697 Journal article (peer-reviewed)abstract The glomerular capillary tuft is a highly specialized microcapillary that is dedicated to function as a sophisticated molecular sieve. The glomerulus filter has a unique molecular composition, and several essential glomerular proteins are expressed in the kidney exclusively by glomerular podocytes. A catalog of > 300 glomerulus-upregulated transcripts that were identified using expressed sequence tag profiling and microarray analysis was published recently. This study characterized the expression profile of five glomerulus-upregulated transcripts/proteins (ehd3, dendrin, sh2d4a, plekhh2, and 2310066E14Rik) in detail. The expression pattern of these novel glomerular transcripts in various mouse tissues was studied using reverse transcriptase-PCR, Northern blotting, and in situ hybridization. For studying the distribution of corresponding proteins, polyclonal antibodies were raised against the gene products, and Western blotting, immunofluorescence, and immunoelectron microscopic analyses were performed. Remarkably, it was discovered that all five transcripts/proteins were expressed in the kidney exclusively by glomerular cells. Ehd3 was expressed only by glomerular endothelial cells. Importantly, ehd3 is the first gene ever shown to be expressed exclusively by glomerular endothelial cells and not by other endothelial cells in the kidney. Dendrin, sh2d4a, plekhh2, and 2310066E14Rik, however, were transcribed solely by podocytes. With the use of polyclonal antibodies, dendrin, sh2d4a, and plekhh2 proteins were localized to the slit diaphragm and the foot process, whereas 2310066E14Rik protein was localized to the podocyte major processes and cell body. This study provides fresh insights into glomerular biology and uncovers new possibilities to explore the role of these novel proteins in the glomerular physiology and pathology.
16.	Perisic, Ljubica, et al. (author) Plekhh2, a novel podocyte protein downregulated in human focal segmental glomerulosclerosis, is involved in matrix adhesion and actin dynamics 2012 In: Kidney International. - : Elsevier BV. - 0085-2538 .- 1523-1755. ; 82:10, s. 1071-1083 Journal article (peer-reviewed)abstract Pleckstrin homology domain-containing, family H (with MyTH4 domain), member 2 (Plekhh2) is a 1491-residue intracellular protein highly enriched in renal glomerular podocytes for which no function has been ascribed. Analysis of renal biopsies from patients with focal segmental glomerulosclerosis revealed a significant reduction in total podocyte Plekhh2 expression compared to controls. Sequence analysis indicated a putative a-helical coiled-coil segment as the only recognizable domain within the N-terminal half of the polypeptide, while the C-terminal half contains two PH, a MyTH4, and a FERM domain. We identified a phosphatidylinositol-3-phosphate consensus-binding site in the PH1 domain required for Plekhh2 localization to peripheral regions of cell lamellipodia. The N-terminal half of Plekkh2 is not necessary for lamellipodial targeting but mediates self-association. Yeast two-hybrid screening showed that Plekhh2 directly interacts through its FERM domain with the focal adhesion protein Hic-5 and actin. Plekhh2 and Hic-5 coprecipitated and colocalized at the soles of podocyte foot processes in situ and Hic-5 partially relocated from focal adhesions to lamellipodia in Plekhh2-expressing podocytes. In addition, Plekhh2 stabilizes the cortical actin cytoskeleton by attenuating actin depolymerization. Our findings suggest a structural and functional role for Plekhh2 in the podocyte foot processes.
17.	Perisic, Ljubica, et al. (author) Schip1 Is a Novel Podocyte Foot Process Protein that Mediates Actin Cytoskeleton Rearrangements and Forms a Complex with Nherf2 and Ezrin 2015 In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:3 Journal article (peer-reviewed)abstract Background Podocyte foot process effacement accompanied by actin cytoskeleton rearrangements is a cardinal feature of many progressive human proteinuric diseases. Results By microarray profiling of mouse glomerulus, SCHIP1 emerged as one of the most highly enriched transcripts. We detected Schip1 protein in the kidney glomerulus, specifically in podocytes foot processes. Functionally, Schip1 inactivation in zebrafish by morpholino knock-down results in foot process disorganization and podocyte loss leading to proteinuria. In cultured podocytes Schip1 localizes to cortical actin-rich regions of lamellipodia, where it forms a complex with Nherf2 and ezrin, proteins known to participate in actin remodeling stimulated by PDGF beta signaling. Mechanistically, overexpression of Schip1 in vitro causes accumulation of cortical F-actin with dissolution of transversal stress fibers and promotes cell migration in response to PDGF-BB stimulation. Upon actin disassembly by latrunculin A treatment, Schip1 remains associated with the residual F-actin-containing structures, suggesting a functional connection with actin cytoskeleton possibly via its interaction partners. A similar assay with cytochalasin D points to stabilization of cortical actin cytoskeleton in Schip1 overexpressing cells by attenuation of actin depolymerisation. Conclusions Schip1 is a novel glomerular protein predominantly expressed in podocytes, necessary for the zebrafish pronephros development and function. Schip1 associates with the cortical actin cytoskeleton network and modulates its dynamics in response to PDGF signaling via interaction with the Nherf2/ezrin complex. Its implication in proteinuric diseases remains to be further investigated.
18.	Petäjäniemi, Noora, et al. (author) Localization of laminin alpha4-chain in developing and adult human tissues 2002 In: Journal of Histochemistry and Cytochemistry. - : SAGE Publications. - 0022-1554 .- 1551-5044. ; 50:8, s. 1113-1130 Journal article (peer-reviewed)abstract Recent studies suggest important functions for laminin-8 (Ln-8; alpha4beta1gamma1) in vascular and blood cell biology, but its distribution in human tissues has remained elusive. We have raised a monoclonal antibody (MAb) FC10, and by enzyme-linked immunoassay (EIA) and Western blotting techniques we show that it recognizes the human Ln alpha4-chain. Immunoreactivity for the Ln alpha4-chain was localized in tissues of mesodermal origin, such as basement membranes (BMs) of endothelia, adipocytes, and skeletal, smooth, and cardiac muscle cells. In addition, the Ln alpha4-chain was found in regions of some epithelial BMs, including epidermis, salivary glands, pancreas, esophageal and gastric glands, intestinal crypts, and some renal medullary tubules. Developmental differences in the distribution of Ln alpha4-chain were detected in skeletal muscle, walls of vessels, and intestinal crypts. Ln alpha4- and Ln alpha2-chains co-localized in BMs of fetal skeletal muscle cells and in some epithelial BMs, e.g., in gastric glands and acini of pancreas. Cultured human pulmonary artery endothelial (HPAE) cells produced Ln alpha4-chain as M(r) 180,000 and 200,000 doublet and rapidly deposited it to the growth substratum. In cell-free extracellular matrices of human kidney and lung, Ln alpha4-chain was found as M(r) 180,000 protein.
19.	Qian, Hong, et al. (author) Contribution of {alpha}6-integrins to hematopoietic stem and progenitor cell homing to bone marrow and collaboration with {alpha}4-integrins. 2006 In: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 107:Jan 26, s. 3503-3510 Journal article (peer-reviewed)abstract The laminin receptor integrin alpha 6 chain is ubiquitously expressed in human and mouse hematopoietic stem and progenitor cells. We have studied its role for homing of stem and progenitor cells to mouse hematopoietic tissues In vivo. A function-blocking anti-integrin alpha 6 antibody significantly reduced progenitor cell homing to bone marrow (BM) of lethally irradiated mice, with a corresponding retention of progenitors in blood. Remarkably, the anti-integrin alpha 6 antibody profoundly inhibited BM homing of long-term multilineage engrafting stem cells, studied by competitive repopulation assay and analysis of donor-derived lymphocytes and myeloid cells in blood 16 weeks after transplantation. A similar profound inhibition of long-term stem cell homing was obtained by using a function-blocking antibody against alpha 4 integrin, studied in parallel. Furthermore, the anti-integrin alpha 6 and alpha 4 antibodies synergistically inhibited homing of short-term repopulating stem cells. Intravenous injection of anti-integrin alpha 6 antibodies, in contrast to antibodies against alpha 4 integrin, did not mobilize progenitors or enhance cytokine-induced mobilization by G-CSF. Our results provide the first evidence for a distinct functional role of integrin alpha 6 receptor during hematopoietic stem and progenitor cell homing and collaboration of alpha 6 integrin with alpha 4 integrin receptors during homing of short-term stem cells.
20.	Qian, Hong, et al. (author) Distinct roles of integrins alpha 6 and alpha 4 in fetal liver hematopoietic stem and progenitor cell homing 2008 In: Cell Research. - : Springer Science and Business Media LLC. - 1748-7838 .- 1001-0602. ; 18 Conference paper (peer-reviewed)
21.	Qian, Hong, et al. (author) Distinct roles of integrins {alpha}6 and {alpha}4 in homing of fetal liver hematopoietic stem and progenitor cells. 2007 In: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 110:7, s. 2399-2407 Journal article (peer-reviewed)abstract Homing of hematopoietic stem cells (HSCs) into the bone marrow (BM) is a prerequisite for establishment of hematopoiesis during development and following transplantation. However, the molecular interactions that control homing of HSCs, in particular, of fetal HSCs, are not well understood. Herein, we studied the role of the alpha 6 and alpha A integrin receptors for homing and engraftment of fetal liver (FL) HSCs and hernatopoietic progenitor cells (HPCs) to adult BM by using integrin alpha 6 gene-deleted mice and functionblocking antibodies. Both integrins were ubiquitously expressed in FL Lin(-)Sca1 (+)Kit(+) (LSK) cells. Deletion of integrin alpha 6 receptor or inhibition by a functionblocking antibody inhibited FL LSK cell adhesion to its extracellular ligands, laminins-411 and -511 in vitro, and significantly reduced homing of HPCs to BM. In contrast, the anti-integrin alpha 6 antibody did not inhibit BM homing of HSCs. In agreement with this, integrin alpha 6 gene-deleted FL HSCs did not display any homing or engraftment defect compared with wildtype littermates. In contrast, inhibition of integrin alpha 4 receptor by a functionblocking antibody virtually abrogated homing of both FL HSCs and HPCs to BM, indicating distinct functions for integrin alpha 6 and alpha 4 receptors during homing of fetal HSCs and HPCs.
22.	Rodriguez, Patricia Q., et al. (author) Knockdown of Tmem234 in zebrafish results in proteinuria 2015 In: AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY. - : American Physiological Society. - 1931-857X .- 1522-1466. ; 309:11, s. F955-F966 Journal article (peer-reviewed)abstract Podocytes are highly specialized epithelial cells located at the outer aspects of the glomerular capillary tuft and critical components of the kidney filtration barrier. To maintain their unique features, podocytes express a number of proteins that are only sparsely found elsewhere in the body. In this study, we have identified four (Tmem234, Znf185, Lrrc49, and Slfn5) new highly podocyte-enriched proteins. The proteins are strongly expressed by podocytes, while other parts of the kidney show only weak or no expression. Tmem234, Slfn5, and Lrrc49 are located in foot processes, whereas Znf185 is found in both foot and major processes. Expressional studies in developing kidneys show that these proteins are first expressed at the capillary stage glomerulus, the same stage when the formation of major and foot processes begins. We identified zebrafish orthologs for Tmem234 and Znf185 genes and knocked down their expression using morpholino technology. Studies in zebrafish larvae indicate that Tmem234 is essential for the organization and functional integrity of the pronephric glomerulus filtration barrier, as inactivation of Tmem234 expression results in foot process effacement and proteinuria. In summary, we have identified four novel highly podocyte - enriched proteins and show that one of them, Tmem234, is essential for the normal filtration barrier in the zebrafish pronephric glomerulus. Identification of new molecular components of the kidney filtration barrier opens up possibilities to study their role in glomerulus biology and diseases.
23.	Rodriguez, Patricia Q., et al. (author) Novel INF2 mutation p. L77P in a family with glomerulopathy and Charcot-Marie-Tooth neuropathy 2013 In: Pediatric nephrology (Berlin, West). - : Springer Science and Business Media LLC. - 0931-041X .- 1432-198X. ; 28:2, s. 339-343 Journal article (peer-reviewed)abstract Mutations in inverted formin, FH2, and WH2 domain containing (INF2) are common causes of dominant focal segmental glomerulosclerosis. INF2 encodes a member of the diaphanous-related formin family, which regulates actin and microtubule cytoskeletons. Charcot-Marie-Tooth neuropathy (CMT) is a group of inherited disorders affecting peripheral neurons. Many reports have shown that glomerulopathy can associate with CMT. However, it has been unclear whether these two processes in the same individual represent one disorder or if they are two separate diseases. Recently, INF2 mutations were identified in 12 of 16 patients with CMT-associated glomerulopathy, suggesting that these mutations are a common cause of the dual phenotype. In this study, we report two cases of CMT-associated glomerulopathy that both showed INF2 mutations. A novel INF2 mutation, p. L77P, was identified in a family in which the dual phenotype was inherited in a dominant fashion. The pathogenic effect of p. L77P was proposed using a structural homology model. In addition, we identified a patient with a sporadic CMT-associated glomerulopathy carrying a known INF2 mutation: p. L128P. Our study confirms the link between INF2 mutations and CMT-associated glomerulopathy and widens the spectrum of pathogenic mutations.
24.	Sandholm, Niina, et al. (author) Genome-wide association study of urinary albumin excretion rate in patients with type 1 diabetes 2014 In: Diabetologia. - Berlin Heidelberg : Springer-Verlag. - 0012-186X .- 1432-0428. ; 57:6, s. 1143-1153 Journal article (peer-reviewed)abstract AIMS/HYPOTHESIS: An abnormal urinary albumin excretion rate (AER) is often the first clinically detectable manifestation of diabetic nephropathy. Our aim was to estimate the heritability and to detect genetic variation associated with elevated AER in patients with type 1 diabetes.METHODS: The discovery phase genome-wide association study (GWAS) included 1,925 patients with type 1diabetes and with data on 24 h AER. AER was analysed as a continuous trait and the analysis was stratified by the use of antihypertensive medication. Signals with a p value <10(-4) were followed up in 3,750 additional patients withtype 1 diabetes from seven studies.RESULTS: The narrow-sense heritability, captured with our genotyping platform, was estimated to explain 27.3% of the total AER variability, and 37.6% after adjustment for covariates. In the discovery stage, five single nucleotide polymorphisms in the GLRA3 gene were strongly associated with albuminuria (p < 5 × 10(-8)). In the replication group, a nominally significant association (p = 0.035) was observed between albuminuria and rs1564939 in GLRA3, but this was in the opposite direction. Sequencing of the surrounding genetic region in 48 Finnish and 48 UK individuals supported the possibility that population-specific rare variants contribute to the synthetic associationobserved at the common variants in GLRA3. The strongest replication (p = 0.026) was obtained for rs2410601 between the PSD3 and SH2D4A genes. Pathway analysis highlighted natural killer cell mediated immunity processes.CONCLUSIONS/INTERPRETATION: This study suggests novel pathways and molecular mechanisms for the pathogenesis of albuminuria in type 1 diabetes.
25.	Sandholm, Niina, et al. (author) New susceptibility loci associated with kidney disease in type 1 diabetes 2012 In: PLOS Genetics. - San Francisco, USA : Public Library of Science, PLOS. - 1553-7390 .- 1553-7404. ; 8:9, s. e1002921- Journal article (peer-reviewed)abstract Diabetic kidney disease, or diabetic nephropathy (DN), is a major complication of diabetes and the leading cause of end-stage renal disease (ESRD) that requires dialysis treatment or kidney transplantation. In addition to the decrease in the quality of life, DN accounts for a large proportion of the excess mortality associated with type 1 diabetes (T1D). Whereas the degree of glycemia plays a pivotal role in DN, a subset of individuals with poorly controlled T1D do not develop DN. Furthermore, strong familial aggregation supports genetic susceptibility to DN. However, the genes and the molecular mechanisms behind the disease remain poorly understood, and current therapeutic strategies rarely result in reversal of DN. In the GEnetics of Nephropathy: an International Effort (GENIE) consortium, we have undertaken a meta-analysis of genomewide association studies (GWAS) of T1D DN comprising similar to 2.4 million single nucleotide polymorphisms (SNPs) imputed in 6,691 individuals. After additional genotyping of 41 top ranked SNPs representing 24 independent signals in 5,873 individuals, combined meta-analysis revealed association of two SNPs with ESRD: rs7583877 in the AFF3 gene (P = 1.2 x 10(-8)) and an intergenic SNP on chromosome 15q26 between the genes RGMA and MCTP2, rs12437854 (P = 2.0 x 10(-9)). Functional data suggest that AFF3 influences renal tubule fibrosis via the transforming growth factor-beta (TGF-beta 1) pathway. The strongest association with DN as a primary phenotype was seen for an intronic SNP in the ERBB4 gene (rs7588550, P = 2.1 x 10(-7)), a gene with type 2 diabetes DN differential expression and in the same intron as a variant with cis-eQTL expression of ERBB4. All these detected associations represent new signals in the pathogenesis of DN.
26.	Sandhow, Lakshmi, et al. (author) Skin mesenchymal niches maintain and protect AML-initiating stem cells 2023 In: Journal of Experimental Medicine. - 0022-1007 .- 1540-9538. ; 220:10 Journal article (peer-reviewed)abstract Leukemia cutis or leukemic cell infiltration in skin is one of the common extramedullary manifestations of acute myeloid leukemia (AML) and signifies a poorer prognosis. However, its pathogenesis and maintenance remain understudied. Here, we report massive AML cell infiltration in the skin in a transplantation-induced MLL-AF9 AML mouse model. These AML cells could regenerate AML after transplantation. Prospective niche characterization revealed that skin harbored mesenchymal progenitor cells (MPCs) with a similar phenotype as BM mesenchymal stem cells. These skin MPCs protected AML-initiating stem cells (LSCs) from chemotherapy in vitro partially via mitochondrial transfer. Furthermore, Lama4 deletion in skin MPCs promoted AML LSC proliferation and chemoresistance. Importantly, more chemoresistant AML LSCs appeared to be retained in Lama4−/− mouse skin after cytarabine treatment. Our study reveals the characteristics and previously unrecognized roles of skin mesenchymal niches in maintaining and protecting AML LSCs during chemotherapy, meriting future exploration of their impact on AML relapse.
27.	Sigmundsson, Kristmundur, et al. (author) Culturing functional pancreatic islets on α5-laminins and curative transplantation to diabetic mice. 2018 In: Matrix Biology. - : Elsevier BV. - 0945-053X .- 1569-1802. ; 70, s. 5-19 Journal article (peer-reviewed)abstract The efficacy of islet transplantation for diabetes treatment suffers from lack of cadaver-derived islets, islet necrosis and long transfer times prior to transplantation. Here, we developed a method for culturing mouse and human islets in vitro on α5-laminins, which are natural components of islet basement membranes. Adhering islets spread to form layers of 1-3 cells in thickness and remained normoxic and functional for at least 7 days in culture. In contrast, spherical islets kept in suspension developed hypoxia and central necrosis within 16 h. Transplantation of 110-150 mouse islets cultured on α5-laminin-coated polydimethylsiloxane membranes for 3-7 days normalized blood glucose already within 3 days in mice with streptozotocin-induced diabetes. RNA-sequencing of isolated and cultured mouse islets provided further evidence for the adhesion and spreading achieved with α5-laminin. Our results suggest that use of such in vitro expanded islets may significantly enhance the efficacy of islet transplantation treatment for diabetes.
28.	Sistani, Laleh, et al. (author) Pdlim2 is a novel actin-regulating protein of podocyte foot processes 2011 In: Kidney International. - : Elsevier BV. - 0085-2538 .- 1523-1755. ; 80:10, s. 1045-1054 Journal article (peer-reviewed)abstract The slit diaphragm and the apical and basal membrane domains of podocytes are connected to each other by an actin-based cytoskeleton critical to the maintenance of the glomerular filtration barrier. In an effort to discover novel regulatory proteins of the podocyte foot process, we identified and characterized pdlim2, a member of the actin-associated LIM protein subfamily of cytosolic proteins typified by an N-terminal PDZ domain and a C-terminal LIM domain. In the kidney, the pdlim2 protein is highly specific for the glomerulus and podocyte foot processes as shown by RT-PCR, western blotting, immunofluorescence, and immunoelectron microscopy. In cultured podocytes, pdlim2 was associated with stress fibers and cortical actin. Pdlim2 seems to regulate actin dynamics in podocytes since stress fibers were stabilized in its presence. Mechanistically, pdlim2 interacts with two actin-associated podocyte proteins, alpha-actinin-4 and angiomotin-like-1, as shown by immunoprecipitation and yeast two-hybrid analyses. By semi-quantitative immunoelectron microscopy, there was a reduced expression of pdlim2 in podocytes of patients with minimal change nephrotic syndrome and membranous nephropathy, whereas its expression was unchanged in patients with focal segmental glomerulosclerosis. Hence, pdlim2 is a novel actin-regulating protein of podocyte foot processes that may have a role in the pathogenesis of glomerular diseases.
29.	Stoltzfus, Patricia, et al. (author) Laminin-5 gamma2 chain expression facilitates detection of invasive squamous cell carcinoma of the uterine cervix. 2004 In: International Journal of Gynecological Pathology. - : Lippincott Williams & Wilkins. - 0277-1691 .- 1538-7151. ; 23:3, s. 215-222 Journal article (peer-reviewed)abstract Because it has been suggested that laminin-5 can be used as a sensitive marker for epithelial cell invasion, specimens from patients with invasive squamous cell carcinoma of the uterine cervix with a previous history of preinvasive lesions were evaluated by a newly developed monoclonal antibody directed against the gamma2 chain of laminin-5. Thirty-two archival paraffin specimens consisting of the matched preinvasive and invasive lesions from 15 women were evaluated to determine whether gamma2 chain laminin-5 staining was present in lesions that progressed to invasive cancer. With the exception of one tumor (a small cell nonkeratinizing squamous carcinoma), all squamous cell carcinomas exhibited positive staining. Five of 17 preinvasive lesions also were immunoreactive for the laminin-5 protein. A blinded histologic reevaluation revealed invasion or lesions suspicious for invasion in four of five preinvasive lesions. Our findings suggest that laminin-5 determined by a monoclonal antibody facilitates the identification of invasive lesions that are difficult or impossible to identify on routinely stained histologic sections.
30.	Sun, Ying, et al. (author) Glomerular Transcriptome Changes Associated with Lipopolysaccharide-Induced Proteinuria 2009 In: American Journal of Nephrology. - : S. Karger AG. - 0250-8095 .- 1421-9670. ; 29:6, s. 558-570 Journal article (peer-reviewed)abstract Background: Global gene expression patterns have recently been characterized in normal glomeruli, but gene expression changes that accompany glomerular disease remain poorly characterized. Method: Here, we mapped global glomerular gene expression profile changes occurring in conjunction with lipopolysaccharide (LPS)-induced proteinuria in mice. Results: We observed dramatic transcriptional reprogramming in glomeruli in response to LPS, representing some 20% of all genes and about 45% of the genes that are normally highly expressed in glomeruli. Bioinformatic analysis revealed significant changes in transcripts encoding proteins involved in the regulation of adherence junctions, actin cytoskeleton and survival in podocytes. In the LPS-treated mice, we observed dysregulation of genes expressed in glomerular endothelial and mesangial cells and in podocytes, there was also a significant decrease in podocyte number. Moreover, collagen alpha 1, alpha 2 (IV) and laminin 10 (laminin alpha 5 beta 1 gamma 1), which are expressed in immature glomeruli, were upregulated in the glomeruli of LPS-treated mice, suggesting remodeling of the glomerular basement membrane and activation of mesangial cells. By superimposing the LPS-induced changes onto GlomNet, a protein-protein interaction network was predicted for podocyte proteins affected by LPS. Conclusions: The detected changes in glomerular gene expression and their involvement in protein interaction networks provide putative markers for early and transient glomerular injury and proteinuria. Copyright (c) 2009 S. Karger AG, Basel
31.	Takemoto, Minoru, et al. (author) Large-scale identification of genes implicated in kidney glomerulus development and function. 2006 In: The EMBO journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 25:5, s. 1160-74 Journal article (peer-reviewed)abstract To advance our understanding of development, function and diseases in the kidney glomerulus, we have established and large-scale sequenced cDNA libraries from mouse glomeruli at different stages of development, resulting in a catalogue of 6053 different genes. The glomerular cDNA clones were arrayed and hybridized against a series of labeled targets from isolated glomeruli, non-glomerular kidney tissue, FACS-sorted podocytes and brain capillaries, which identified over 300 glomerular cell-enriched transcripts, some of which were further sublocalized to podocytes, mesangial cells and juxtaglomerular cells by in situ hybridization. For the earliest podocyte marker identified, Foxc2, knockout mice were used to analyze the role of this protein during glomerular development. We show that Foxc2 controls the expression of a distinct set of podocyte genes involved in podocyte differentiation and glomerular basement membrane maturation. The primary podocyte defects also cause abnormal differentiation and organization of the glomerular vascular cells. We surmise that studies on the other novel glomerulus-enriched transcripts identified in this study will provide new insight into glomerular development and pathomechanisms of disease.
32.	Tran-Lundmark, Karin, et al. (author) Heparan sulfate in perlecan promotes mouse atherosclerosis: roles in lipid permeability, lipid retention, and smooth muscle cell proliferation. 2008 In: Circulation research. - 1524-4571. ; 103:1, s. 43-52 Journal article (peer-reviewed)abstract Heparan sulfate (HS) has been proposed to be antiatherogenic through inhibition of lipoprotein retention, inflammation, and smooth muscle cell proliferation. Perlecan is the predominant HS proteoglycan in the artery wall. Here, we investigated the role of perlecan HS chains using apoE null (ApoE0) mice that were cross-bred with mice expressing HS-deficient perlecan (Hspg2(Delta3/Delta3)). Morphometry of cross-sections from aortic roots and en face preparations of whole aortas revealed a significant decrease in lesion formation in ApoE0/Hspg2(Delta3/Delta3) mice at both 15 and 33 weeks. In vitro, binding of labeled mouse triglyceride-rich lipoproteins and human LDL to total extracellular matrix, as well as to purified proteoglycans, prepared from ApoE0/Hspg2(Delta3/Delta3) smooth muscle cells was reduced. In vivo, at 20 minutes influx of human (125)I-LDL or mouse triglyceride-rich lipoproteins into the aortic wall was increased in ApoE0/Hspg2(Delta3/Delta3) mice compared to ApoE0 mice. However, at 72 hours accumulation of (125)I-LDL was similar in ApoE0/Hspg2(Delta3/Delta3) and ApoE0 mice. Immunohistochemistry of lesions from ApoE0/Hspg2(Delta3/Delta3) mice showed decreased staining for apoB and increased smooth muscle alpha-actin content, whereas accumulation of CD68-positive inflammatory cells was unchanged. We conclude that the perlecan HS chains are proatherogenic in mice, possibly through increased lipoprotein retention, altered vascular permeability, or other mechanisms. The ability of HS to inhibit smooth muscle cell growth may also influence development as well as instability of lesions.
33.	Wermeling, Fredrik, et al. (author) Class A scavenger receptors regulate tolerance against apoptotic cells, and autoantibodies against these receptors are predictive of systemic lupus 2007 In: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 204:10, s. 2259-2265 Journal article (peer-reviewed)abstract Apoptotic cells are considered to be a major source for autoantigens in autoimmune diseases such as systemic lupus erythematosus (SLE). In agreement with this, defective clearance of apoptotic cells has been shown to increase disease susceptibility. Still, little is known about how apoptotic cell-derived self-antigens activate autoreactive B cells and where this takes place. In this study, we find that apoptotic cells are taken up by specific scavenger receptors expressed on macrophages in the splenic marginal zone and that mice deficient in these receptors have a lower threshold for autoantibody responses. Furthermore, antibodies against scavenger receptors are found before the onset of clinical symptoms in SLE-prone mice, and they are also found in diagnosed SLE patients. Our findings describe a novel mechanism where autoantibodies toward scavenger receptors can alter the response to apoptotic cells, affect tolerance, and thus promote disease progression. Because the autoantibodies can be detected before onset of disease in mice, they could have predictive value as early indicators of SLE.
34.	Wu, Chuan, et al. (author) Endothelial basement membrane laminin alpha 5 selectively inhibits T lymphocyte extravasation into the brain 2009 In: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 15:5, s. 519-527 Journal article (peer-reviewed)abstract Specific inhibition of the entry of encephalitogenic T lymphocytes into the central nervous system in multiple sclerosis would provide a means of inhibiting disease without compromising innate immune responses. We show here that targeting lymphocyte interactions with endothelial basement membrane laminins provides such a possibility. In mouse experimental autoimmune encephalomyelitis, T lymphocyte extravasation correlates with sites expressing laminin alpha 4 and small amounts of laminin alpha 5. In mice lacking laminin alpha 4, laminin alpha 5 is ubiquitously expressed along the vascular tree, resulting in marked and selective reduction of T lymphocyte infiltration into the brain and reduced disease susceptibility and severity. Vessel phenotype and immune response were not affected in these mice. Rather, laminin alpha 5 directly inhibited integrin alpha(6)beta(1)-mediated migration of T lymphocytes through laminin alpha 4. The data indicate that T lymphocytes use mechanisms distinct from other immune cells to penetrate the endothelial basement membrane barrier, permitting specific targeting of this immune cell population.
35.	Xiao, Zhijie, et al. (author) Wtip- and Gadd45a-Interacting Protein Dendrin Is Not Crucial for the Development or Maintenance of the Glomerular Filtration Barrier 2013 In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12, s. e83133- Journal article (peer-reviewed)abstract Glomerular podocyte cells are critical for the function of the renal ultrafiltration barrier. Especially, the highly specialized cell cell junction of podocytes, the slit diaphragm, has a central role in the filtration barrier. This is highlighted by the fact that mutations in molecular components of the slit diaphragm, inclucling nephrin and Cd2-associated protein (Cd2ap), result in proteinuric diseases in man. Dendrin is a poorly characterized cytosalic component of the slit diaphragm in where it interact h nephrin and Cd2ap. Dendrin is highly specific for the podocyte slit diaphragm, suggesting that it has a dedicated role in glomerular filtration barrier. In this study, we have generated a dendrin knockout mouse line and explored the molecular interactions of dendrin. Dendrin-deficient mice were viable, fertile, and had a normal life span. Morphologically, the glomerulogenesis proceeded normally and adult dendrin-deficient mice showed normal glomerular histology. No significant protainuria was observed. Fallowing glomerular injury, lack of dendrin did not affect the severity of the damage or h recovery process. Yeast two-hybrid screen and co-immunoprecipitation experiments showed that dendrin binds to interacting protein (Wtip) and growth arrest and DNA-damage-inducible 45 alpha (Gadd45a). Wtip and Gadd45a mediate gene transcription in the nucleus, suggesting that dendrin may have similar functions in podacytes In line with this, we observed he relocation of dendrin to nucleus in adriamycin nephropathy model. Our results indicate that dendrin is dispensable forth unction of the normal glomerular filtration barrier and that dendrin interacts with Wtip and Gadd45a.
36.	Xu, Xiangjun, et al. (author) Expression of novel podocyte-associated proteins sult1b1 and ankrd25. 2011 In: Nephron. Experimental nephrology. - : S. Karger AG. - 1660-2129. ; 117:2, s. e39-46 Journal article (peer-reviewed)abstract BACKGROUND/AIMS: Podocytes have a unique function in the renal ultrafiltration that is achieved by expressing proteins that are highly specific to podocytes. In this study, we identified two novel podocyte-associated proteins.METHODS: The expression of sult1b1 and ankrd25 in mouse tissues was studied by RT-PCR. The protein expression was studied by generating polyclonal antibodies that were used in Western blotting and immunohistochemistry.RESULTS: By RT-PCR we detected sult1b1 expression only in glomerular, liver and brain tissues. By immunohistochemistry, sult1b1 was detected in the kidney exclusively in the Golgi apparatus of the podocyte. No expression outside the glomerulus was observed in the kidney. The ankrd25 transcript was detected in most mouse tissues analyzed by RT-PCR. In the kidney, however, immunohistochemistry showed that this protein was expressed only by podocyte, mesangial, and smooth muscle cells. In podocytes, ankrd25 was localized to foot processes.CONCLUSIONS: Identification of these two novel glomerulus-associated proteins opens up possibilities to investigate their role in the renal filter physiology and diseases. We speculate that sult1b1 may be involved in the sulfonylation of podocyte protein podocalyxin, whereas ankrd25 may contribute to controlling actin dynamics in podocyte foot processes.

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