Temporal expression profiles of ceramide and ceramide-related genes in wild-type and mPer1/mPer2 double knockout mice

2011 ◽  
Vol 39 (4) ◽  
pp. 4215-4221 ◽  
Author(s):  
Yeong-Su Jang ◽  
Yeo-Jin Kang ◽  
Tack-Joong Kim ◽  
Kiho Bae
Keyword(s):  
Knockout Mice ◽  
Expression Profiles ◽  
Wild Type ◽  
Temporal Expression ◽  
Double Knockout

scholarly journals Rhythmic changes in colonic motility are regulated by period genes

2010 ◽  
Vol 298 (2) ◽  
pp. G143-G150 ◽  
Author(s):  
Willemijntje A. Hoogerwerf ◽  
Vahakn B. Shahinian ◽  
Germaine Cornélissen ◽  
Franz Halberg ◽  
Jonathon Bostwick ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Clock Genes ◽  
Ex Vivo ◽  
Colonic Motility ◽  
Biological Clock ◽  
Circular Muscle ◽  
Organ Bath ◽  
Wild Type ◽  
Double Knockout ◽  
Muscle Contractility

Human bowel movements usually occur during the day and seldom during the night, suggesting a role for a biological clock in the regulation of colonic motility. Research has unveiled molecular and physiological mechanisms for biological clock function in the brain; less is known about peripheral rhythmicity. This study aimed to determine whether clock genes such as period 1 ( per1) and period2 ( per2) modulate rhythmic changes in colonic motility. Organ bath studies, intracolonic pressure measurements, and stool studies were used to examine measures of colonic motility in wild-type and per1per2 double-knockout mice. To further examine the mechanism underlying rhythmic changes in circular muscle contractility, additional studies were completed in neuronal nitric oxide synthase (nNOS) knockout mice. Intracolonic pressure changes and stool output in vivo, and colonic circular muscle contractility ex vivo, are rhythmic with greatest activity at the start of night in nocturnal wild-type mice. In contrast, rhythmicity in these measures was absent in per1per2 double-knockout mice. Rhythmicity was also abolished in colonic circular muscle contractility of wild-type mice in the presence of Nω-nitro-l-arginine methyl ester and in nNOS knockout mice. These findings suggest that rhythms in colonic motility are regulated by both clock genes and a nNOS-mediated inhibitory process and suggest a connection between these two mechanisms.

Defective water and glycerol transport in the proximal tubules of AQP7 knockout mice

2005 ◽  
Vol 289 (6) ◽  
pp. F1195-F1200 ◽  
Author(s):  
Eisei Sohara ◽  
Tatemitsu Rai ◽  
Jun-ichi Miyazaki ◽  
A. S. Verkman ◽  
Sei Sasaki ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Water Channel ◽  
Physiological Role ◽  
Wild Type ◽  
Double Knockout ◽  
Straight Tubule ◽  
Glycerol Transport ◽  
Straight Tubules ◽  
Proximal Straight Tubule ◽  
Urinary Concentrating Ability

The aquaporin-7 (AQP7) water channel is known as a member of the aquaglyceroporins, which facilitate the transport of glycerol as well as water. Although AQP7 is abundantly expressed on the apical membrane of the proximal straight tubules in the kidney, the physiological role of AQP7 is still unknown. To investigate this, we generated AQP7 knockout mice. The water permeability of the proximal tubule brush-border membrane measured by the stopped-flow method was slightly but significantly reduced in the AQP7 knockout mice compared with that of wild-type mice (AQP7, 18.0 ± 0.4 × 10−3 cm/s vs. wild-type, 20.0 ± 0.3 × 10−3 cm/s). Although AQP7 solo-knockout mice did not exhibit a urinary concentrating defect, AQP1/AQP7 double-knockout mice had a reduction in urinary concentrating ability compared with AQP1 solo-knockout mice, suggesting that the amount of water reabsorbed through AQP7 in the proximal straight tubules is physiologically substantial. On the other hand, AQP7 knockout mice showed marked glyceroluria (AQP7, 1.7 ± 0.34 mg/ml vs. wild-type, 0.005 ± 0.002 mg/ml). This identified a novel glycerol reabsorption pathway in the proximal straight tubules. In two mouse models of proximal straight tubule injury, the cisplatin-induced acute renal failure (ARF) model and the ischemic ARF model, an increase in urine glycerol was observed (pretreatment, 0.007 ± 0.005 mg/ml; cisplatin, 0.063 ± 0.043 mg/ml; ischemia, 0.076 ± 0.02 mg/ml), suggesting that urine glycerol could be used as a new biomarker for detecting proximal straight tubule injury.

scholarly journals MFN1 and MFN2 Are Dispensable for Sperm Development and Functions in Mice

2021 ◽  
Vol 22 (24) ◽  
pp. 13507
Author(s):  
Junru Miao ◽  
Wei Chen ◽  
Pengxiang Wang ◽  
Xin Zhang ◽  
Lei Wang ◽  
...  
Keyword(s):  
Germ Cells ◽  
Knockout Mice ◽  
Seminiferous Tubules ◽  
Wild Type ◽  
Double Knockout ◽  
Wild Type Littermate ◽  
Mitofusin 2 ◽  
Sperm Development ◽  
Mitofusin 1 ◽  
Deficient Mice

MFN1 (Mitofusin 1) and MFN2 (Mitofusin 2) are GTPases essential for mitochondrial fusion. Published studies revealed crucial roles of both Mitofusins during embryonic development. Despite the unique mitochondrial organization in sperm flagella, the biological requirement in sperm development and functions remain undefined. Here, using sperm-specific Cre drivers, we show that either Mfn1 or Mfn2 knockout in haploid germ cells does not affect male fertility. The Mfn1 and Mfn2 double knockout mice were further analyzed. We found no differences in testis morphology and weight between Mfn-deficient mice and their wild-type littermate controls. Spermatogenesis was normal in Mfn double knockout mice, in which properly developed TRA98+ germ cells, SYCP3+ spermatocytes, and TNP1+ spermatids/spermatozoa were detected in seminiferous tubules, indicating that sperm formation was not disrupted upon MFN deficiency. Collectively, our findings reveal that both MFN1 and MFN2 are dispensable for sperm development and functions in mice.

scholarly journals ADAMTS13 Synergizes with HDL in Preventing Von Willebrand Factor Self-Association Under Shear Stress

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3451-3451
Author(s):  
Dominic W Chung ◽  
Junmei Chen ◽  
Minhua Ling ◽  
Taisha Doo ◽  
Teri Blevens ◽  
...  
Keyword(s):  
Shear Stress ◽  
Human Plasma ◽  
Von Willebrand Factor ◽  
Knockout Mice ◽  
Tube Surface ◽  
Wild Type ◽  
Double Knockout ◽  
Self Association ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Von Willebrand factor (VWF) is a plasma glycoprotein that mediates platelet adhesion at sites of vessel injury. It is synthesized in megakaryocytes and endothelial cells and is assembled in the endoplasmic reticulum and Golgi into an array of multimers. Upon secretion from microvascular endothelium, VWF multimers can further self-associate under shear stress and form surface-bound fibers of potentially enormous sizes capable of spanning the lumens of vessels up to 300 mm in diameter (Zheng et al. Nature Communications 2015 In press). These structures are normally removed by the plasma metalloprotease ADAMTS13. However, when ADAMTS13 is inactivated or when massive VWF secretion overwhelms the capacity of ADAMTS13 to process VWF, these structures persist in the microcirculation and bind platelets avidly to form occlusive thrombi, a process characteristic of the devastating disease thrombotic thrombocytopenic purpura (TTP). These microvascular VWF-platelet thrombi have also been implicated in the microvascular dysfunction that accompanies malaria, sickle cell disease, and sepsis. We recently identified high density lipoprotein particles (HDL) as being able to prevent VWF self-association into thick strands (Chung et al. Blood 2015 in revision). In these studies, we also studied VWF self-association in citrated human plasma under shear stress in a test tube in the presence of EDTA (to inhibit ADAMTS13). VWF self-associated and adsorbed to the tube surface, a phenomenon prevented by addition of HDL at concentrations above those already present in plasma. When EDTA was not added to the plasma, the majority of the VWF was not cleaved but was nevertheless stabilized in solution. This result suggests that when ADAMTS13 has been progressively inactivated by citrate at 37°C, it is able to prevent VWF self-association. It is not clear why EDTA-inhibited ADAMTS13 did not stabilize VWF to the same extent as citrate-inhibited ADAMTS13. It is possible that EDTA and citrate have different effects on the stabilization function of ADAMTS13. Further, addition of recombinant ADAMTS13 to citrated plasma (final ratio VWF monomer:ADAMTS13 = 1.6:1) did not enhance VWF cleavage under shear, but completely stabilized the VWF multimers. These results demonstrate a new function for ADAMTS13: it regulates VWF adhesive activity by preventing VWF self-association through direct binding instead of cleavage. Therefore, we hypothesize that the relative levels of VWF, HDL, and ADAMTS13 in plasma regulate the propensity of VWF multimers to self-associate under shear stress. While high VWF levels and high shear stress favor VWF self-association, high HDL and ADAMTS13 levels prevent self-association. We tested the hypothesis with plasma from wild-type or knockout mice on the C57BL6 background. In comparison to humans, wild-type C57BL6 mice have low VWF levels, high HDL levels (calculated from HDL-cholesterol levels), and express a truncated version of ADAMTS13. Further, ADAMTS13-deficient C57BL6 mice do not spontaneously develop microvascular occlusion. Unlike human citrated plasma, when citrated plasma from wild-type mice was sheared in the presence of EDTA, the VWF multimers did not self-associate. We attributed this difference from human plasma to the low VWF:HDL ratio in this mouse strain. When the plasma from apolipoprotein (Apo) A-I knockout mice was sheared in the presence of EDTA, the VWF multimers also did not self-associate, which we attributed to the low VWF level and the ability of EDTA-inhibited truncated ADAMTS13 to stabilize VWF. When the plasma of a double knockout of ApoA-I and ADAMTS13 was sheared, the VWF self-associated and adsorbed to the tube surface. Addition of HDL to this double knockout plasma stabilized the VWF. The VWF antigen levels in wild-type, single and double knockout mouse plasma were comparable. Double knockout mice challenged with a bolus injection of VWF developed more severe thrombocytopenia than did mice with either single ApoA-I or ADAMTS13 deficiency. Together, these results suggest that ADAMTS13 synergizes with HDL in stabilizing VWF and dampening its self-association into hyperadhesive forms under shear stress, and that interplay between concentrations of VWF, ADAMTS13, and HDL particles can determine the propensity for developing TTP and its severity once developed. Disclosures No relevant conflicts of interest to declare.

scholarly journals Role of thin descending limb urea transport in renal urea handling and the urine concentrating mechanism

2011 ◽  
Vol 301 (6) ◽  
pp. F1251-F1259 ◽  
Author(s):  
Tianluo Lei ◽  
Lei Zhou ◽  
Anita T. Layton ◽  
Hong Zhou ◽  
Xuejian Zhao ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Gene Knockout ◽  
Embryonic Stem ◽  
Urine Osmolality ◽  
Peripheral Circulation ◽  
Solute Concentration ◽  
Urine Concentration ◽  
Wild Type ◽  
Double Knockout ◽  
Knockout Mouse Model

Urea transporters UT-A2 and UT-B are expressed in epithelia of thin descending limb of Henle's loop and in descending vasa recta, respectively. To study their role and possible interaction in the context of the urine concentration mechanism, a UT-A2 and UT-B double knockout (UT-A2/B knockout) mouse model was generated by targeted deletion of the UT-A2 promoter in embryonic stem cells with UT-B gene knockout. The UT-A2/B knockout mice lacked detectable UT-A2 and UT-B transcripts and proteins and showed normal survival and growth. Daily urine output was significantly higher in UT-A2/B knockout mice than that in wild-type mice and lower than that in UT-B knockout mice. Urine osmolality in UT-A2/B knockout mice was intermediate between that in UT-B knockout and wild-type mice. The changes in urine osmolality and flow rate, plasma and urine urea concentration, as well as non-urea solute concentration after an acute urea load or chronic changes in protein intake suggested that UT-A2 plays a role in the progressive accumulation of urea in the inner medulla. These results suggest that in wild-type mice UT-A2 facilitates urea absorption by urea efflux from the thin descending limb of short loops of Henle. Moreover, UT-A2 deletion in UT-B knockout mice partially remedies the urine concentrating defect caused by UT-B deletion, by reducing urea loss from the descending limbs to the peripheral circulation; instead, urea is returned to the inner medulla through the loops of Henle and the collecting ducts.

scholarly journals Reprogramming the chiA expression profile of Autographa californica multiple nucleopolyhedrovirus

2007 ◽  
Vol 88 (9) ◽  
pp. 2479-2487 ◽  
Author(s):  
Jeffrey J. Hodgson ◽  
Basil M. Arif ◽  
Peter J. Krell
Keyword(s):  
Expression Profiles ◽  
Temporal Analysis ◽  
Autographa Californica ◽  
Environmentally Benign ◽  
Wild Type ◽  
Temporal Expression ◽  
Transcription Profiles ◽  
Multiple Nucleopolyhedrovirus ◽  
First Time ◽  
Autographa Californica Multiple Nucleopolyhedrovirus

Expression of chiA and v-cath RNA and enzyme activity in wild-type Autographa californica multiple nucleopolyhedrovirus (AcMNPV) was compared with that of recombinant AcMNPV viruses reprogrammed for expression of the endogenous chiA. To establish a baseline for our recombinant AcMNPV studies, we compared, for the first time, the temporal expression profiles of both AcMNPV chiA transcription and translation simultaneously. The rate of intracellular chitinase accumulation during AcMNPV infection followed the same pattern observed for chiA transcription but was delayed by about 6 h. Replacement of 21 nucleotides containing the native late chiA and v-cath promoters with a selectable polh–EGFP cassette was sufficient to eliminate expression of both chiA and v-cath. Viruses were generated that express chiA from either the late p6.9 or very late polh promoters of AcMNPV, replacing the native chiA promoter. There was a marked difference in the temporal chiA transcription profiles from the native, p6.9 and polh promoters, resulting in respective specific activities of chitinase at 48 h p.i. of 62, 160 and 219 mU (mg lysate total protein)−1. Based on temporal analysis of v-cath transcription by Northern blot, AcMNPV v-cath was transcribed from 9 h p.i. in Sf21 cells. However, expression of v-cath RNA or enzyme from a reconstructed v-cath promoter in the chiA-reprogrammed viruses was not detected at 48 h of virus replication. Reprogramming for increased chitinase (and putatively cathepsin) expression with native baculovirus promoters might provide a means for designing environmentally benign biological insecticides.

Multidrug-resistance mdr1a/1b double knockout mice are more sensitive than wild type mice to acute arsenic toxicity, with higher arsenic accumulation in tissues

Toxicology ◽  
2002 ◽  
Vol 170 (1-2) ◽  
pp. 55-62 ◽  
Author(s):  
Jie Liu ◽  
Yaping Liu ◽  
Douglas A Powell ◽  
Michael P Waalkes ◽  
Curtis D Klaassen
Keyword(s):  
Multidrug Resistance ◽  
Knockout Mice ◽  
Arsenic Toxicity ◽  
Wild Type ◽  
Double Knockout ◽  
Arsenic Accumulation

Abstract 327: SR-BI Deficiency and Hypercholesterolemia Synergistically Lead to Impaired Erythropoiesis

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Zhiqing Song ◽  
Ling Guo ◽  
Xiang-An Li
Keyword(s):  
Knockout Mice ◽  
High Fat Diet ◽  
Plasma Cholesterol ◽  
Scavenger Receptor ◽  
Fold Increase ◽  
Wild Type ◽  
High Fat ◽  
Double Knockout ◽  
Scavenger Receptor Bi ◽  
Cholesterol Levels

Recent studies showed that mice deficient in scavenger receptor BI (SR-BI) exhibit impaired erythropoiesis and it has been proposed that the high cholesterol environment plays a major role in the abnormal erythropoiesis. In this study, we utilized three animal models to assess the role of SR-BI and hypercholesterolemia in erythropoiesis. First, we used a high fat diet-induced hypercholesterolemia model. High fat diet caused a 2-fold increase in plasma cholesterol levels in SR-BI +/+ (172 mg/dl to 350 mg/dl) and SR-BI -/- mice (313 mg/dl to 716 mg/dl). The high fat diet treatment markedly exacerbated the impaired erythropoiesis in SR-BI -/- mice as shown by 4-fold increase in reticulocyte percentage and 2.5-fold increase in early-to-late erythroblast ratio. Unexpectedly, high fat feeding did not induce abnormal erythropoiesis in SR-BI +/+ mice despite of hypercholesterolemia in these mice. We then used SR-BI/LDLR double knockout mice to further elucidate the contribution of hypercholesterolemia to erythropoiesis. SR-BI/LDLR double knockout mice had 2-fold increase in plasma cholesterol levels and exhibited severer impaired erythropoiesis, similar to high fat-fed SR-BI -/- mice. Interestingly, despite of hyperlipidemia, LDLR single knockout mice did not display impaired erythropoiesis. Finally, we investigated the contribution of hepatic SR-BI using ScarbI I179N mutant mice, whose hepatic SR-BI expression has been knocked down by 90% and therefore has a 1.7-fold increase in plasma cholesterol levels compared to wild type controls. ScarbI I179N mice displayed normal erythropoiesis, similar to wild type controls. These findings indicate that hypercholesterolemia does not cause abnormal erythropoiesis in the presence of SR-BI, but markedly impairs erythropoiesis in the absence of SR-BI. We conclude that SR-BI is essential for normal erythropoiesis, and that hypercholesterolemia and SR-BI deficiency synergistically exacerbated impaired erythropoiesis.

Phenotype analysis of aquaporin-8 null mice

2005 ◽  
Vol 288 (5) ◽  
pp. C1161-C1170 ◽  
Author(s):  
Baoxue Yang ◽  
Yuanlin Song ◽  
Dan Zhao ◽  
A. S. Verkman
Keyword(s):  
Salivary Gland ◽  
Knockout Mice ◽  
Plasma Membranes ◽  
Fluid Secretion ◽  
Intestinal Loop ◽  
Wild Type ◽  
Double Knockout ◽  
Mild Phenotype ◽  
Testicular Weight ◽  
Urinary Concentrating Ability

Aquaporin-8 (AQP8) is a water-transporting protein expressed in organs of the mammalian gastrointestinal tract (salivary gland, liver, pancreas, small intestine, and colon) and in the testes, heart, kidney, and airways. We studied the phenotype of AQP8-null mice, and mice lacking AQP8, together with AQP1 or AQP5. AQP8-knockout mice lacked detectable AQP8 transcript and protein, and had reduced water permeability in plasma membranes from testes. Breeding of AQP8 heterozygous mice yielded AQP8-null mice, whose number, survival, and growth were not different from those of wild-type mice. Organ weight and serum/urine chemistries were similar in wild-type and AQP8-null mice, except for increased testicular weight in the null mice (4.8 ± 0.7 vs. 7.3 ± 0.3 mg/g body wt). Urinary concentrating ability in AQP8-null mice was unimpaired as assessed by urine osmolality (3,590 ± 360 mosmol/kgH2O) and weight loss (22 ± 2%) after 36-h water deprivation; urinary concentrating ability was similarly impaired in AQP1-null mice vs. AQP8/AQP1 double-knockout mice. Agonist-driven fluid secretion in salivary gland was not different in AQP8 vs. wild-type mice (∼1 μl·min−1·g body wt−1) or in AQP5-null mice vs. AQP8/AQP5 double-knockout mice. Closed intestinal loop measurements in vivo indicated unimpaired osmotically driven water transport, active fluid absorption, and cholera toxin-driven fluid secretion in AQP8-null mice. After 21 days on a 50% fat diet, wild-type and AQP8-null mice had similar weight gain (∼15 g), with no evidence of steatorrhea or abnormalities in blood chemistries, except for mild hypertriglyceridemia in the null mice. The mild phenotype of AQP8-null mice was surprising in view of the multiple phenotype abnormalities found in mouse models of AQP1–5 deficiency.

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