Replacement of connexin 40 by connexin 45 causes ectopic localization of renin-producing cells in the kidney but maintains in vivo control of renin gene expression

2009 ◽  
Vol 297 (2) ◽  
pp. F403-F409 ◽  
Author(s):  
Lisa Kurtz ◽  
Melanie Gerl ◽  
Wilhelm Kriz ◽  
Charlotte Wagner ◽  
Armin Kurtz
Keyword(s):  
Gene Expression ◽  
Wild Type ◽  
Renin Gene ◽  
Connexin 40 ◽  
Renin Mrna ◽  
The Media ◽  
Afferent Arterioles ◽  
Deficient Mice ◽  
Media Layer

Deletion of connexin 40 (Cx40) leads to ectopic hyperplasia of renin-producing cells in the kidney, which is associated with dysregulated hyperreninemia and hypertension. The aim of this study was to determine whether Cx45 is able to substitute the function of Cx40 with regard to the localization of renin-producing cells. For this purpose, we have studied the distribution of renin-expressing cells under both normal conditions and during a stimulatory challenge of the renin system by inducing salt deprivation in mice, achieved by replacing the coding sequence of the Cx40 gene with that of Cx45 (Cx40ki45). In both wild-type (WT) mice and Cx40ki45 mice under normal conditions, renin-expressing cells were located at the juxtaglomerular position, whereas in Cx40-deficient mice they were located in the periglomerular interstitium. Upon challenge of the renin system, renin mRNA and the number of renin-expressing cells increased in WT mice in the media layer of afferent arterioles, while neither parameter changed significantly in Cx40-deficient mice. In Cx40ki45 mice, challenge of the renin system markedly increased both renin mRNA and the number of renin-expressing cells. However, the newly recruited renin-expressing cells were localized mainly outside the afferent vessels in the periglomerular interstitium. We found no evidence of cell divisions in renin-expressing cells in any of the genotypes investigated in this study, suggesting that the ectopically localized, renin-expressing cells in Cx40ki45 mice were already preexisting but were not renin-expressing under normal conditions. In summary, we infer from our findings that the function of Cx40 for the localization of potential renin-producing cells cannot be substituted by that of Cx45, although the regulability of renin gene expression can.

Acute hypoxia stimulates renin secretion and renin gene expression in vivo but not in vitro

1997 ◽  
Vol 272 (4) ◽  
pp. R1105-R1111 ◽  
Author(s):  
T. Ritthaler ◽  
K. Schricker ◽  
F. Kees ◽  
B. Kramer ◽  
A. Kurtz
Keyword(s):  
Gene Expression ◽  
Acute Hypoxia ◽  
Primary Cultures ◽  
Renin Secretion ◽  
Plasma Norepinephrine ◽  
Mrna Levels ◽  
Sprague Dawley ◽  
Renin Gene ◽  
Renin Mrna

This study aimed at examining the influence of acute hypoxia on renin secretion and renin gene expression in the kidney. To this end, male Sprague-Dawley rats were exposed to severe hypoxic stress (8% O2) or to carbon monoxide (0.1% CO) for 6 h, and plasma renin activity (PRA) and renal renin mRNA levels were determined. PRA values increased from 3 to 13 and 10 ng angiotensin I x h(-1) x ml(-1), and renin mRNA levels increased by 120 and 100% during hypoxia and CO, respectively. Lowering the PO2 from 150 to 20 or 7 mmHg in the gas atmosphere of primary cultures of renal juxtaglomerular cells had no influence on renin secretion and renin gene expression after 6 and 20 h. Our findings thus suggest that both arterial and venous hypoxia can be powerful stimulators of renin secretion and renin gene expression in vivo. Because renal denervation did not prevent stimulation of the renin system by hypoxia, the effect could be indirectly mediated via the baroreceptor-macula densa mechanism. Another potential mediator of the effect could be circulating catecholamines, since we found that plasma norepinephrine increased from 0.7 to 1.5 and 2.4 ng/ml and plasma epinephrine increased from 0.3 to 1.4 and 2.7 ng/ml during hypoxia and CO inhalation, respectively.

scholarly journals ASXL2 Is Recurrently Mutated in t(8;21) AML and Regulates Hematopoietic Development

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1051-1051
Author(s):  
Vikas Madan ◽  
Lin Han ◽  
Norimichi Hattori ◽  
Anand Mayakonda ◽  
Qiao-Yang Sun ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Research Funding ◽  
Hematopoietic Differentiation ◽  
Wild Type ◽  
Flow Cytometric ◽  
Deficient Mice

Abstract Chromosomal translocation t(8;21) (q22;q22) leading to generation of oncogenic RUNX1-RUNX1T1 fusion is a cytogenetic abnormality observed in about 10% of acute myelogenous leukemia (AML). Studies in animal models and recent next generation sequencing approaches have suggested cooperativity of secondary genetic lesions with t(8;21) in inducing leukemogenesis. In this study, we used targeted and whole exome sequencing of 93 cases (including 30 with matched relapse samples) to profile the mutational landscape of t(8;21) AML at initial diagnosis and post-therapy relapse. We identified recurrent mutations of KIT, TET2, MGA, FLT3, NRAS, DHX15, ASXL1 and KMT2Dgenes in this subtype of AML. In addition, high frequency of truncating alterations in ASXL2 gene (19%) also occurred in our cohort. ASXL2 is a member of mammalian ASXL family involved in epigenetic regulation through recruitment of polycomb or trithorax complexes. Unlike its closely related homolog ASXL1, which is mutated in several hematological malignancies including AML, MDS, MPN and others; mutations of ASXL2 occur specifically in t(8;21) AML. We observed that lentiviral shRNA-mediated silencing of ASXL2 impaired in vitro differentiation of t(8;21) AML cell line, Kasumi-1, and enhanced its colony forming ability. Gene expression analysis uncovered dysregulated expression of several key hematopoiesis genes such as IKZF2, JAG1, TAL1 and ARID5B in ASXL2 knockdown Kasumi-1 cells. Further, to investigate implications of loss of ASXL2 in vivo, we examined hematopoiesis in Asxl2 deficient mice. We observed an age-dependent increase in white blood cell count in the peripheral blood of Asxl2 KO mice. Myeloid progenitors from Asxl2 deficient mice possessed higher re-plating ability and displayed altered differentiation potential in vitro. Flow cytometric analysis of >1 year old mice revealed increased proportion of Lin-Sca1+Kit+ (LSK) cells in the bone marrow of Asxl2 deficient mice, while the overall bone marrow cellularity was significantly reduced. In vivo 5-bromo-2'-deoxyuridine incorporation assay showed increased cycling of LSK cells in mice lacking Asxl2. Asxl2 deficiency also led to perturbed maturation of myeloid and erythroid precursors in the bone marrow, which resulted in altered proportions of mature myeloid populations in spleen and peripheral blood. Further, splenomegaly was observed in old ASXL2 KO mice and histological and flow cytometric examination of ASXL2 deficient spleens demonstrated increased extramedullary hematopoiesis and myeloproliferation compared with the wild-type controls. Surprisingly, loss of ASXL2 also led to impaired T cell development as indicated by severe block in maturation of CD4-CD8- double negative (DN) population in mice >1 year old. These findings established a critical role of Asxl2 in maintaining steady state hematopoiesis. To gain mechanistic insights into its role during hematopoietic differentiation, we investigated changes in histone marks and gene expression affected by loss of Asxl2. Whole transcriptome sequencing of LSK population revealed dysregulated expression of key myeloid-specific genes including Mpo, Ltf, Ngp Ctsg, Camp and Csf1rin cells lacking Asxl2 compared to wild-type control. Asxl2 deficiency also caused changes in histone modifications, specifically H3K27 trimethylation levels were decreased and H2AK119 ubiquitination levels were increased in Asxl2 KO bone marrow cells. Global changes in histone marks in control and Asxl2 deficient mice are being investigated using ChIP-Sequencing. Finally, to examine cooperativity between the loss of Asxl2 and RUNX1-RUNX1T1 in leukemogenesis, KO and wild-type fetal liver cells were transduced with retrovirus expressing AML1-ETO 9a oncogene and transplanted into irradiated recipient mice, the results of this ongoing study will be discussed. Overall, our sequencing studies have identified ASXL2 as a gene frequently altered in t(8;21) AML. Functional studies in mouse model reveal that loss of ASXL2 causes defects in hematopoietic differentiation and leads to myeloproliferation, suggesting an essential role of ASXL2 in normal and malignant hematopoiesis. *LH and NH contributed equally Disclosures Ogawa: Takeda Pharmaceuticals: Consultancy, Research Funding; Sumitomo Dainippon Pharma: Research Funding; Kan research institute: Consultancy, Research Funding.

Increased expression of cyclooxygenase 2 contributes to aberrant renin production in connexin 40-deficient kidneys

2007 ◽  
Vol 293 (5) ◽  
pp. R1781-R1786 ◽  
Author(s):  
Charlotte Wagner ◽  
Cor de Wit ◽  
Melanie Gerl ◽  
Armin Kurtz ◽  
Klaus Höcherl
Keyword(s):  
Plasma Renin ◽  
Cyclooxygenase 2 ◽  
Mrna Levels ◽  
Connexin 40 ◽  
Renin Mrna ◽  
The Media ◽  
Afferent Arterioles ◽  
Cox 2 ◽  
Cox 2 Inhibitors ◽  
Inhibitor Treatment

We previously found that deletion of connexin 40 (Cx40) causes a misdirection of renin-expressing cells from the media layer of afferent arterioles to the perivascular tissue, extraglomerular mesangium, and periglomerular and peritubular interstitium. The mechanisms underlying this aberrant renin expression are unknown. Here, we questioned the relevance of cyclooxygenase-2 (COX-2) activity for aberrant renin expression in Cx40-deficient kidneys. We found that COX-2 mRNA levels were increased three-fold in the renal cortex of Cx40-deficient kidneys relative to wild-type (wt) kidneys. In wt kidneys, COX-2 immunoreactivity was minimally detected in the juxtaglomerular region, but renin expression was frequently associated with COX-2 immunoreactivity in Cx40-deficient kidneys. Treatment with COX-2 inhibitors for 1 wk lowered renin mRNA levels in wt kidneys by about 40%. In Cx40-deficient kidneys, basal renin mRNA levels were increased two-fold relative to wt kidneys, and these elevated mRNA levels were reduced to levels of untreated wt mice by COX-2 inhibitors. In parallel, renin immunoreactive areas were clearly reduced by COX-2 inhibitors such that renin expression vanished and decreased significantly in the periglomerular and peritubular extensions. Notably, COX-2 inhibitor treatment lowered plasma renin concentration (PRC) in wt kidneys by about 40% but did not affect the highly elevated PRC levels in Cx40-deficient mice. These findings suggest that aberrant renin-producing cells in Cx40-deficient kidneys express significant amounts of COX-2, which contribute to renin expression in these cells, in particular, those in the periglomerular and peritubular position. Apparently, these disseminated cells do not contribute to the enhanced renin secretion rates of Cx40-deficient kidneys.

scholarly journals Systems Modeling of the Role of Interleukin-21 in the Maintenance of Effector CD4+ T Cell Responses during Chronic Helicobacter pylori Infection

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Adria Carbo ◽  
Danyvid Olivares-Villagómez ◽  
Raquel Hontecillas ◽  
Josep Bassaganya-Riera ◽  
Rupesh Chaturvedi ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
T Cell ◽  
Wild Type ◽  
Content Type ◽  
Interleukin 21 ◽  
H Pylori ◽  
Deficient Mice

ABSTRACTThe development of gastritis duringHelicobacter pyloriinfection is dependent on an activated adaptive immune response orchestrated by T helper (Th) cells. However, the relative contributions of the Th1 and Th17 subsets to gastritis and control of infection are still under investigation. To investigate the role of interleukin-21 (IL-21) in the gastric mucosa duringH. pyloriinfection, we combined mathematical modeling of CD4+T cell differentiation within vivomechanistic studies. We infected IL-21-deficient and wild-type mice withH. pyloristrain SS1 and assessed colonization, gastric inflammation, cellular infiltration, and cytokine profiles. ChronicallyH. pylori-infected IL-21-deficient mice had higherH. pyloricolonization, significantly less gastritis, and reduced expression of proinflammatory cytokines and chemokines compared to these parameters in infected wild-type littermates. Thesein vivodata were used to calibrate anH. pyloriinfection-dependent, CD4+T cell-specific computational model, which then described the mechanism by which IL-21 activates the production of interferon gamma (IFN-γ) and IL-17 during chronicH. pyloriinfection. The model predicted activated expression of T-bet and RORγt and the phosphorylation of STAT3 and STAT1 and suggested a potential role of IL-21 in the modulation of IL-10. Driven by our modeling-derived predictions, we found reduced levels of CD4+splenocyte-specifictbx21androrcexpression, reduced phosphorylation of STAT1 and STAT3, and an increase in CD4+T cell-specific IL-10 expression inH. pylori-infected IL-21-deficient mice. Our results indicate that IL-21 regulates Th1 and Th17 effector responses during chronicH. pyloriinfection in a STAT1- and STAT3-dependent manner, therefore playing a major role controllingH. pyloriinfection and gastritis.IMPORTANCEHelicobacter pyloriis the dominant member of the gastric microbiota in more than 50% of the world’s population.H. pyloricolonization has been implicated in gastritis and gastric cancer, as infection withH. pyloriis the single most common risk factor for gastric cancer. Current data suggest that, in addition to bacterial virulence factors, the magnitude and types of immune responses influence the outcome of colonization and chronic infection. This study uses a combined computational and experimental approach to investigate how IL-21, a proinflammatory T cell-derived cytokine, maintains the chronic proinflammatory T cell immune response driving chronic gastritis duringH. pyloriinfection. This research will also provide insight into a myriad of other infectious and immune disorders in which IL-21 is increasingly recognized to play a central role. The use of IL-21-related therapies may provide treatment options for individuals chronically colonized withH. pylorias an alternative to aggressive antibiotics.

scholarly journals Effects of Saline, an Ambient Acidic Environment, and Sodium Salicylate on OXA-Mediated Carbapenem Resistance in Acinetobacter baumannii: TABLE 1

2016 ◽  
Vol 60 (6) ◽  
pp. 3415-3418 ◽  
Author(s):  
Esther Zander ◽  
Harald Seifert ◽  
Paul G. Higgins
Keyword(s):  
Gene Expression ◽  
Acinetobacter Baumannii ◽  
Sodium Salicylate ◽  
Carbapenem Resistance ◽  
Low Ph ◽  
Wild Type ◽  
Experimental Conditions ◽  
Content Type ◽  
Reference Strains

Different physiological conditions, such as NaCl, low pH, and sodium salicylate, have been shown to affect antibiotic resistance determinants inAcinetobacter baumanniiisolates. Therefore, the aim of this study was to investigate the effects of NaCl, sodium salicylate, and low pH on the susceptibility ofA. baumanniito carbapenem. We cloned genes encoding oxacillinases (OXA) of different subclasses, with their associated promoters, from carbapenem-resistantA. baumanniiisolates into the same vector and transferred them to theA. baumanniireference strains ATCC 19606 and ATCC 17978. Carbapenem MICs were determined at least in triplicate by agar dilution under standard conditions, as well as in the presence of 200 mM NaCl or 16 mM sodium salicylate, or at pH 5.8. OXA-58-like gene expression was determined by reverse transcription-quantitative PCR (qRT-PCR). Under some experimental conditions, significant MIC reductions were shown for some transformants but not for others. Only in one instance were all transformants harboring the same OXA affected by the same condition: at pH 5.8, the imipenem and meropenem MICs for strains expressing OXA-58-like enzymes decreased from a resistant level (32 to 64 mg/liter) to an intermediate-susceptible level (8 mg/liter). However,blaOXA-58-likegene expression remained the same. MICs for both wild-type reference strains were not affected by the conditions tested. Our results indicate that the effects of the experimental conditions tested on OXAin vivoare mostly strain dependent. MICs were not reduced to wild-type levels, suggesting that the conditions tested do not lead to complete OXA inhibition in the bacterial cell.

Urokinase-dependent plasminogen activation is required for efficient skeletal muscle regeneration in vivo

Blood ◽  
2001 ◽  
Vol 97 (6) ◽  
pp. 1703-1711 ◽  
Author(s):  
Frederic Lluı́s ◽  
Josep Roma ◽  
Mònica Suelves ◽  
Maribel Parra ◽  
Gloria Aniorte ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasminogen Activator ◽  
Muscle Regeneration ◽  
Plasminogen Activators ◽  
Skeletal Muscle Regeneration ◽  
Plasminogen Activation ◽  
Wild Type ◽  
Type Plasminogen Activator ◽  
Deficient Mice

Plasminogen activators urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) are extracellular proteases involved in various tissue remodeling processes. A requirement for uPA activity in skeletal myogenesis was recently demonstrated in vitro. The role of plasminogen activators in skeletal muscle regeneration in vivo in wild-type, uPA-deficient, and tPA-deficient mice is investigated here. Wild-type and tPA−/− mice completely repaired experimentally damaged skeletal muscle. In contrast, uPA−/− mice had a severe regeneration defect, with decreased recruitment of blood-derived monocytes to the site of injury and with persistent myotube degeneration. In addition, uPA-deficient mice accumulated fibrin in the degenerating muscle fibers; however, the defibrinogenation of uPA-deficient mice resulted in a correction of the muscle regeneration defect. A similar severe regeneration deficit with persistent fibrin deposition was also reproducible in plasminogen-deficient mice after injury, suggesting that fibrinolysis by uPA-mediated plasminogen activation plays a fundamental role in skeletal muscle regeneration. In conclusion, the uPA-plasmin system is identified as a critical component of the mammalian skeletal muscle regeneration process, possibly because it prevents intramuscular fibrin accumulation and contributes to the adequate inflammatory response after injury. These studies demonstrate the requirement of an extracellular proteolytic cascade during muscle regeneration in vivo.

scholarly journals Differential gene expression between wild-type and Gulo-deficient mice supplied with vitamin C

2011 ◽  
Vol 34 (3) ◽  
pp. 386-395 ◽  
Author(s):  
Yan Jiao ◽  
Jifei Zhang ◽  
Jian Yan ◽  
John Stuart ◽  
Griffin Gibson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Vitamin C ◽  
Differential Gene Expression ◽  
Wild Type ◽  
Differential Gene ◽  
Deficient Mice

scholarly journals An in vivo inflammatory loop potentiates KRAS blockade

2019 ◽  
Author(s):  
Kristina A.M. Arendt ◽  
Giannoula Ntaliarda ◽  
Vasileios Armenis ◽  
Danai Kati ◽  
Christin Henning ◽  
...  
Keyword(s):  
Interleukin 1Β ◽  
Wild Type ◽  
Poor Survival ◽  
Murine Bone Marrow ◽  
Chemokine Ligand ◽  
Isoprenylcysteine Carboxylmethyltransferase ◽  
Chemokine Ligand 2 ◽  
Deficient Mice

ABSTRACTKRAS inhibitors perform inferior to other targeted drugs. To investigate a possible reason for this, we treated cancer cells with KRAS inhibitors deltarasin (targeting phosphodiesterase-δ), cysmethynil (targeting isoprenylcysteine carboxylmethyltransferase), and AA12 (targeting KRASG12C), and silenced/overexpressed mutant KRAS using custom vectors. We show that KRAS-mutant tumor cells exclusively respond to KRAS blockade in vivo, because the oncogene co-opts host myeloid cells via a C-C-motif chemokine ligand 2/interleukin-1β signaling loop for sustained tumorigenicity. Indeed, KRAS-mutant tumors did not respond to deltarasin in Ccr2 and Il1b gene-deficient mice, but were deltarasin-sensitive in wild-type and Ccr2-deficient mice adoptively transplanted with wild-type murine bone marrow. A KRAS-dependent pro-inflammatory transcriptome was prominent in human cancers with high KRAS mutation prevalence and predicted poor survival. Hence the findings support that in vitro systems are suboptimal for anti-KRAS drug screens, and suggest that interleukin-1β blockade might be specific for KRAS-mutant cancers.

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