scholarly journals Investigating the Roles of Platelet PAR4 in Hemostasis, Thrombosis and Viral Infection Using a Newly Generated PAR4 Floxed Mouse

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1000-1000
Author(s):  
Robert H Lee ◽  
Tomohiro Kawano ◽  
Vanthana Bharathi ◽  
David Martinez ◽  
Dale O Cowley ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Carotid Artery ◽  
Viral Infection ◽  
Saphenous Vein ◽  
Influenza A ◽  
Body Weight Loss ◽  
Cell Type ◽  
Laser Injury ◽  
Plug Formation

Abstract Introduction: Protease-activated receptor 4 (PAR4) is expressed by a wide variety of cells, including megakaryocytes/platelets, immune cells, cardiomyocytes and lung epithelial cells, and activated by multiple ligands including thrombin and cathepsin G. Importantly, PAR4 is the only functional thrombin receptor on murine platelets. A global deficiency of PAR4 is associated with impaired hemostasis and protection from thrombosis which are attributed to loss of platelet PAR4, but this has not been specifically demonstrated in mice. Additionally, global PAR4 deficiency increases mortality after influenza A virus infection, but the cell type/s responsible for the enhanced mortality have not been determined. Here, we describe the generation of PAR4 floxed (PAR4 fl/fl) mice that can be used to delete PAR4 in a cell type-specific manner, and examine the effect of megakaryocyte/platelet-specific deletion of PAR4 on hemostasis, thrombosis and viral infection using PAR4 fl/fl;PF4Cre + mice. Methods: PAR4global knockout (PAR4 -/-), MK/platelet-specific knockout (PAR4 fl/fl;PF4Cre +) and appropriate littermate control mice were used for experiments. Platelet function was determined by light transmission aggregometry and flow cytometry. Hemostasis was assessed in the saphenous vein laser injury model. Platelet plug formation was visualized by intravital microscopy following saphenous vein laser ablation (~50 μm diameter injury), followed by 2 subsequent ablations to reinjure the same site unless on-going bleeding was occurring. Mice were treated with ibrutinib (12.5 mg/kg) to inhibit GPVI signaling, or dabigatran etexilate (chow containing 10 mg/g) or recombinant hirudin (50 mg/kg) to inhibit thrombin activity. Thrombosis was assessed in the carotid artery FeCl 3 model. The carotid artery was exposed and 8% FeCl 3 applied for 3 mins. Blood flow was observed for 30 mins and occlusion was defined as no blood flow for 2 mins. To study susceptibility to viral infection, mice were challenged intranasally with a mouse-adapted H1N1 influenza A virus (H1N1 IAV PR8; 0.02 hemagglutination assay units), which induces mortality in 20% of WT mice. Mortality was defined as body weight loss greater than 25%, which required euthanasia. Results: As expected, PAR4 fl/fl;PF4Cre + platelets were unresponsive to thrombin or PAR4-specific stimulation, while the response to other agonists was retained. In the saphenous vein laser injury hemostasis model, PAR4 fl/fl;PF4Cre + mice were able to rapidly form a hemostatic platelet plug, but the majority of plugs (7/8) were unstable and re-opened after several minutes, leading to severely prolonged total bleeding times. We observed similar findings in global PAR4 -/- mice with 8/12 plugs re-opening. To investigate the mechanism mediating initial platelet plug formation, we inhibited GPVI signaling in PAR4 fl/fl;PF4Cre + mice using the Btk inhibitor ibrutinib. Ibrutinib administration shortened time to plug re-opening in PAR4 fl/fl;PF4Cre + mice but plugs were still able to form, which is likely mediated by GPIbα/VWF. We observed a similar phenotype to PAR4 fl/fl;PF4Cre + mice in mice treated with the direct thrombin inhibitor hirudin, suggesting thrombin is the primary activator of PAR4 during hemostatic plug formation. In the FeCl 3-induced carotid artery thrombosis model, both PAR4 fl/fl;PF4Cre + and PAR4 -/- mice were significantly protected compared to controls. Finally, when challenged with the mouse-adapted H1N1 IAV PR8, PAR4 fl/fl;PF4Cre + mice demonstrated similar body weight loss and survival as littermate controls. Conclusions: Our results in mice demonstrate that 1) platelet PAR4 is not required for initial hemostatic plug formation but is necessary for maintaining hemostatic plug stability, 2) loss of platelet PAR4 protects from arterial thrombosis, and 3) platelet PAR4 does not alter the course of H1N1 IAV infection, at least at the virus dose used in this study. In summary, we generated a novel mouse line carrying a floxed PAR4 allele which can be used to investigate cell-specific roles of PAR4 in disease. Disclosures No relevant conflicts of interest to declare.

scholarly journals 1343. Prophylactic Dosing of Baloxavir Acid Eliminates Mortality in Mice Lethal Influenza A Virus Infection Model

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S410-S411
Author(s):  
Shinya Shano ◽  
Keita Fukao ◽  
Takeshi Noshi ◽  
Kenji Sato ◽  
Masashi Sakuramoto ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Virus Infection ◽  
Influenza A Virus ◽  
Influenza A ◽  
Lethal Dose ◽  
Body Weight Loss ◽  
Prophylactic Efficacy ◽  
Body Weights ◽  
Single Dosing

Abstract Background Baloxavir acid (BXA), an active form of orally available prodrug baloxavir marboxil (BXM, formerly S-033188), is a novel small molecule inhibitor of cap-dependent endonuclease (CEN) of influenza A and B virus, and was recently launched for the treatment of acute and uncomplicated influenza with single dosing of BXM (the trade name XOFLUZA™) in Japan in March 2018. Here, we evaluated the prophylactic efficacy of BXA in mice lethally infected with influenza A virus. Methods T1/2 of BXA in human is more than 10 times longer than that in mice. Therefore, suspension of BXA was subcutaneously administered at 0.8 or 1.6 mg/kg in mice to maintain the plasma concentration of BXA as seen in humans, and then mice were intranasally inoculated with a lethal dose of A/PR/8/34 strain at 48, 72, or 96 hours after the administration of BXA. Survival time and body weight change were then monitored through a 28-day period after virus infection. Mice were euthanized and regarded as dead if their body weights were lower than 70% of the initial body weights according to humane endpoints. Results Single dosing of BXA (1.6 mg/kg) completely eliminated mortality in mice, when the mice were administrated the drug at 48, 72, or 96 hours before virus infection (Figure 1). BXA treatment also significantly prevented body weight loss, consistent with the prolonged survival. Conclusion Prophylactic dosing of BXA exhibited significant protective efficacy against mortality and body weight loss in mice following a lethal infection with influenza A virus. The significant prophylactic efficacy observed in our mouse model suggests the potential utility of BXM for the prophylaxis of influenza in human. Disclosures S. Shano, Shionogi & Co., Ltd.: Employee, Salary. K. Fukao, Shionogi & Co., Ltd.: Employee, Salary. T. Noshi, Shionogi & Co., Ltd.: Employee, Salary. K. Sato, Shionogi & Co., Ltd.: Employee, Salary. M. Sakuramoto, Shionogi & Co., Ltd.: Employee, Salary. K. Baba, Shionogi TechnoAdvance Research & Co., Ltd.: Employee, Salary. T. Shishido, Shionogi & Co., Ltd.: Employee, Salary. A. Naito, Shionogi & Co., Ltd.: Employee, Salary.

scholarly journals Efficacy of Repeated Intravenous Injection of Peramivir against Influenza A (H1N1) 2009 Virus Infection in Immunosuppressed Mice

2013 ◽  
Vol 57 (5) ◽  
pp. 2286-2294 ◽  
Author(s):  
Mitsutaka Kitano ◽  
Makoto Kodama ◽  
Yasushi Itoh ◽  
Takushi Kanazu ◽  
Masanori Kobayashi ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Virus Infection ◽  
Influenza A ◽  
Body Weight Loss ◽  
Repeated Administration ◽  
Vehicle Group ◽  
Influenza A H1n1 ◽  
Immunosuppressed Mice ◽  
Viral Titers

ABSTRACTThe efficacy of intravenous peramivir against influenza A (H1N1) 2009 virus infection was evaluated in mice in which the immune system was suppressed by cyclophosphamide (CP) treatment. The mortality rate of the vehicle control group was 100%, and the mice lost 20% of their body weight on average by day 13 postinfection (p.i.). Repeated administration of peramivir (40 mg/kg of body weight once a day, given intravenously for 20 days), starting at 1 h p.i., significantly reduced mortality, body weight loss, viral titers, and cytokine production in infected mice compared with results for administration of vehicle (P< 0.01). In addition, repeated administration of peramivir, starting at 24 h, 48 h, or 72 h p.i., also resulted in increases in survival rates and reduction of viral titers in the lungs (P< 0.01). The mean days to death (MDD) of the vehicle group was 14.5 days, while in the groups treated with peramivir starting at 24 h, 48 h, and 72 h p.i., the MDDs were >23.0, 20.9, and 21.8 days, respectively. In comparison, repeated administration of oseltamivir phosphate (5 mg/kg twice a day, given orally for 20 days), starting at 24 h, 48 h, and 72 h p.i., also significantly prevented body weight loss, whereas no significant differences in mortality rates and viral titers in the lungs were observed compared with results for the vehicle group. These data indicated that repeated administration of peramivir was effective in promoting the survival and reducing virus replication in immunosuppressed mice infected with influenza A (H1N1) 2009 virus.

scholarly journals Effect of NMSO3 treatment in a murine model of human metapneumovirus infection

2008 ◽  
Vol 89 (11) ◽  
pp. 2709-2712 ◽  
Author(s):  
Leanne Spetch ◽  
Terry L. Bowlin ◽  
Antonella Casola
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Viral Infection ◽  
Murine Model ◽  
Cytokine Production ◽  
Antiviral Treatment ◽  
Pulmonary Inflammation ◽  
Body Weight Loss ◽  
Human Metapneumovirus ◽  
Time Of Infection

BALB/c mice infected with human metapneumovirus (hMPV) were treated with the sulfated sialyl lipid NMSO3 (one dose of 50 mg kg−1) given at the time of infection. NMSO3 significantly reduced viral replication in the lungs, as well as hMPV-induced body weight loss, pulmonary inflammation and cytokine production, suggesting that antiviral treatment initiated at the beginning of viral infection can modify hMPV-induced disease.

scholarly journals Therapeutic Activity of Intramuscular Peramivir in Mice Infected with a Recombinant Influenza A/WSN/33 (H1N1) Virus Containing the H275Y Neuraminidase Mutation

2012 ◽  
Vol 56 (8) ◽  
pp. 4375-4380 ◽  
Author(s):  
Yacine Abed ◽  
Andrés Pizzorno ◽  
Guy Boivin
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Influenza A ◽  
Low Dose ◽  
Body Weight Loss ◽  
High Dose ◽  
Therapeutic Activity ◽  
Enzymatic Assays ◽  
Oseltamivir Resistance

ABSTRACTThe therapeutic activity of intramuscular (IM) peramivir was evaluated in mice infected with a recombinant influenza A/WSN/33 virus containing the H275Y neuraminidase (NA) mutation known to confer oseltamivir resistance. Regimens consisted of single (90 mg/kg of body weight) or multiple (45 mg/kg daily for 5 days) IM peramivir doses that were initiated 24 h or 48 h postinfection (p.i.). An oral oseltamivir regimen (1 or 10 mg/kg daily for 5 days) was used for comparison. Untreated animals had a mortality rate of 75% and showed a mean weight loss of 16.9% on day 5 p.i. When started at 24 h p.i., both peramivir regimens prevented mortality and significantly reduced weight loss (P< 0.001) and lung viral titers (LVT) (P< 0.001). A high dose (10 mg/kg) of oseltamivir initiated at 24 h p.i. also prevented mortality and significantly decreased weight loss (P< 0.05) and LVT (P< 0.001) compared to the untreated group results. In contrast, a low dose (1 mg/kg) of oseltamivir did not show any benefits. When started at 48 h p.i., both peramivir regimens prevented mortality and significantly reduced weight loss (P< 0.01) and LVT (P< 0.001) whereas low-dose or high-dose oseltamivir regimens had no effect on mortality rates, body weight loss, and LVT. Our results show that single-dose and multiple-dose IM peramivir regimens retain clinical and virological activities against the A/H1N1 H275Y variant despite some reduction in susceptibility when assessedin vitrousing enzymatic assays. IM peramivir could constitute an alternative for treatment of oseltamivir-resistant A/H1N1 infections, although additional studies are warranted to support such a recommendation.

1965-P: Glucagon Receptor Agonism Stimulates Body Weight Loss in Antibiotic Treatment in Obese Mice

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 1965-P
Author(s):  
TEAYOUN KIM ◽  
JESSICA P. ANTIPENKO ◽  
SHELLY NASON ◽  
NATALIE PRESEDO ◽  
WILLIAM J. VAN DER POL ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Antibiotic Treatment ◽  
Body Weight Loss ◽  
Obese Mice ◽  
Glucagon Receptor

Relation between change in treatment for central diabetes insipidus and body weight loss

2018 ◽  
Vol 44 (1) ◽  
Author(s):  
Ayako Ito ◽  
Aya Nozaki ◽  
Ichiro Horie ◽  
Takao Ando ◽  
Atsushi Kawakami
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Diabetes Insipidus ◽  
Body Weight Loss ◽  
Central Diabetes Insipidus

scholarly journals Isoquinoline Alkaloids in Sows’ Diet Reduces Body Weight Loss during Lactation and Increases IgG in Colostrum

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2195
Author(s):  
Ester Arévalo Sureda ◽  
Xuemei Zhao ◽  
Valeria Artuso-Ponte ◽  
Sophie-Charlotte Wall ◽  
Bing Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Weight Loss ◽  
Body Weight ◽  
Body Weight Loss ◽  
Muscle Thickness ◽  
Passive Immunity ◽  
Isoquinoline Alkaloids ◽  
Back Muscle ◽  
Fat Thickness ◽  
And Performance

Isoquinoline alkaloids (IQ) exert beneficial antimicrobial and anti-inflammatory effects in livestock. Therefore, we hypothesized that supplementing sows’ diets with IQ during gestation would decrease farrowing stress, affecting the piglets’ development and performance. Sows were divided into: IQ1, supplemented with IQ from gestation day 80 (G80) to weaning; IQ2, supplemented from gestation day 110 (G110) to weaning, and a non-supplemented (NC) group. Sow body weight (BW), feed intake, back-fat thickness and back-muscle thickness were monitored. Cortisol, glucose and insulin were measured in sows’ blood collected 5 d before, during, and after 7 d farrowing. Protein, fat, IgA and IgG were analyzed in the colostrum and milk. Piglets were monitored for weight and diarrhea score, and for ileum histology and gene expression 5 d post-weaning. IQ-supplemented sows lost less BW during lactation. Glucose and insulin levels were lower in the IQ groups compared to NC-sows 5 d before farrowing and had higher levels of protein and IgG in their colostrum. No other differences were observed in sows, nor in the measured parameters in piglets. In conclusion, IQ supplementation affected sows’ metabolism, reducing body weight loss during lactation. Providing IQ to sows from their entrance into the maternity barn might be sufficient to induce these effects. IQ improved colostrum quality, increasing the protein and IgG content, improving passive immunity for piglets.

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