Abstract 267: Preserved Cardiac Contractility and Venous Return in Beta-arrestin2 Transgenic Mice During Sepsis With Insufficient Resuscitation

β-arrestin 2 is a negative regulator of inflammation and a protective signaling transducer in acute heart injury. In this study, using echocardiography and Millar Pressure-Volume systems, we found that heart dysfunction accompanied with hemodynamic instability occurred rapidly after experimental sepsis with insufficient resuscitation in wild type and β-arrestin 2 knock out mice but not in β-arrestin 2 transgenic mice. β-arrestin 2 overexpression is associated with preserved preload, cardiac output, systolic contractility and diastolic elasticity after cecal ligation and puncture (CLP). Furthermore, β-arrestin 2 overexpression up-regulated IL-6/IL-6R/gp130/STAT3 anti-apoptotic signaling through suppressing p38 activation and subsequently inhibiting phosphorylation of membrane bound gp130, the signal transducer part of IL-6 receptor complex. In conclusion, β-arrestin 2 is a crucial cardiac function regulator in sepsis.

Download Full-text

REST is a major negative regulator of endocrine differentiation during pancreas organogenesis

10.1101/2021.03.17.435876 ◽

2021 ◽

Author(s):

Meritxell Rovira ◽

Goutham Atla ◽

Miguel Angel Maestro ◽

Vane Grau ◽

Javier García-Hurtado ◽

...

Keyword(s):

Endocrine Cells ◽

Negative Regulator ◽

Β Cell ◽

Knock Out ◽

Endocrine Differentiation ◽

Conditional Allele ◽

Embryonic Pancreas ◽

Pancreatic Endocrine Cells ◽

Knock Out Mice

SUMMARYUnderstanding genomic regulatory mechanisms of pancreas differentiation is relevant to the pathophysiology of diabetes mellitus, and to the development of replacement therapies. Numerous transcription factors promote β cell differentiation, although less is known about negative regulators. Earlier epigenomic studies suggested that the transcriptional repressor REST could be a suppressor of endocrine gene programs in the embryonic pancreas. However, pancreaticRestknock-out mice failed to show increased numbers of endocrine cells, suggesting that REST is not a major regulator of endocrine differentiation. Using a different conditional allele that enables profound REST inactivation, we now observe a marked increase in the formation of pancreatic endocrine cells. REST inhibition also promoted endocrinogenesis in zebrafish and mouse early postnatal ducts, and induced β-cell specific genes in human adult duct-derived organoids. Finally, we define REST genomic programs that suppress pancreatic endocrine differentiation. These results establish a crucial role of REST as a negative regulator of pancreatic endocrine differentiation.

Download Full-text

Expression of HbC and HbS, but not HbA, results in activation of K-Cl cotransport activity in transgenic mouse red cells

Blood ◽

10.1182/blood-2003-01-0237 ◽

2004 ◽

Vol 103 (6) ◽

pp. 2384-2390 ◽

Cited By ~ 15

Author(s):

Jose R. Romero ◽

Sandra M. Suzuka ◽

Ronald L. Nagel ◽

Mary E. Fabry

Keyword(s):

Transgenic Mice ◽

Hemoglobin Concentration ◽

Red Cells ◽

Mean Corpuscular Hemoglobin ◽

Red Cell ◽

Knock Out ◽

High K ◽

Hb S ◽

Knock Out Mice ◽

Human Red Cells

Abstract Elevation of K-Cl cotransport in patients with homozygous hemoglobin (Hb) S or HbC increases red cell mean corpuscular hemoglobin concentration (MCHC) and contributes significantly to pathology. Elucidation of the origin of elevated K-Cl cotransport in red cells with mutant hemoglobins has been confounded by the concomitant presence of reticulocytes with high K-Cl cotransport. In red cells of control mice (C57BL), transgenic mice that express only human HbA, and transgenic mice that express both mouse globins and human HbS, volume stimulation is weak and insensitive to NO3- and dihydroindenyl-oxy-alkanoic acid (DIOA). DIOA and NO3- are inhibitors in all other mammalian red cells. In contrast, in knock-out mice expressing exclusively human hemoglobin HbC or HbS+γ, replacement of isotonic Cl- media by hypotonic Cl- resulted in strong volume stimulation and sensitivity to DIOA, okadaic acid, and NO3-. In summary, we find that HbC, under all conditions, and HbS+γ, in the absence of mouse globins, have significant quantitative and qualitative effects on K-Cl cotransport in mouse red cells and activate mouse K-Cl. We conclude that human globins are able to stimulate the activity and/or regulation of K-Cl cotransport in mouse red cells. These observations support the contention that HbS and HbC stimulate K-Cl cotransport in human red cells.

Download Full-text

NF-kappaB activity in transgenic mice: developmental regulation and tissue specificity

Development ◽

10.1242/dev.122.7.2117 ◽

1996 ◽

Vol 122 (7) ◽

pp. 2117-2128 ◽

Cited By ~ 3

Author(s):

R. Schmidt-Ullrich ◽

S. Memet ◽

A. Lilienbaum ◽

J. Feuillard ◽

M. Raphael ◽

...

Keyword(s):

Transgenic Mice ◽

Early Development ◽

Developmental Regulation ◽

Mouse Development ◽

Knock Out ◽

Cellular Genes ◽

Development And Differentiation ◽

The Central Nervous System ◽

Nf Kappab ◽

Knock Out Mice

The transcription factor family NF-kappaB/Rel is responsible for the regulation of a large number of cellular genes and some viruses. Since there is a strong similarity between the NF-kappaB/Rel family members and the Drosophila melanogaster protein DORSAL, which is activated early during embryogenesis, we were interested in determining the pattern of NF-kappaB activity during mouse development. Two lacZ reporter constructs, each driven by promoter elements that are dependent on the presence of nuclear NF-kappaB/Rel activity, were used to produce transgenic mice. The analysis of these mice did not identify nuclear NF-kappaB/Rel activity in early development prior to implantation or during the gastrulation processes. Earliest expression of the lacZ transgene was detected on day E12.5. Before birth lacZ expression was seen in discrete regions of the rhombencephalon of the developing brain, in the spinal medulla, in some of the blood vessels and in the thymus. After birth, the NF-kappaB/Rel activity in the thymus remained but nuclear activity was also found in the bone marrow, in the spleen and in the capsule of the lymph nodes. In the central nervous system, drastic changes in NF-kappaB/Rel activity could be observed in the first 3 weeks after birth, when the cortex and the cerebellum reach functional and morphological maturity. Considering the results of the p50, p65, relB and c-rel knock-out mice and our present findings, we believe that the NF-kappaB/Rel proteins known so far are probably not implicated in processes of early development and differentiation of the different tissues, but rather in maintaining their function once matured.

Download Full-text

Transgenic mice studies demonstrate a role for platelet factor 4 in thrombosis: dissociation between anticoagulant and antithrombotic effect of heparin

Blood ◽

10.1182/blood-2003-11-3994 ◽

2004 ◽

Vol 104 (10) ◽

pp. 3173-3180 ◽

Cited By ~ 105

Author(s):

Don E. Eslin ◽

Chunyan Zhang ◽

Kathleen J. Samuels ◽

Lubica Rauova ◽

Li Zhai ◽

...

Keyword(s):

Transgenic Mice ◽

Thrombus Formation ◽

Platelet Factor 4 ◽

Platelet Factor ◽

Knock Out ◽

Thrombosis Model ◽

Knock Out Mice ◽

Positively Charged

Abstract The platelet-specific chemokine platelet factor 4 (PF4) is released in large amounts at sites of vascular injury. PF4 binds to heparin with high affinity, but its in vivo biologic role has not been defined. We studied the role of PF4 in thrombosis using heterozygote and homozygote PF4 knock-out mice (mPF4+/– and mPF4–/–, respectively) and transgenic mice overexpressing human PF4 (hPF4+). None of these lines had an overt bleeding diathesis, but in a FeCl3 carotid artery thrombosis model, all showed impaired thrombus formation. This defect in thrombus formation in the mPF4–/– animals was corrected by infusing hPF4 over a narrow concentration range. The thrombotic defect in the mPF4+/– and mPF4–/– animals was particularly sensitive to infusions of the negatively charged anticoagulant heparin. However, the same amount of heparin paradoxically normalized thrombus formation in the hPF4+ animals, although these animals were anticoagulated systemically. Upon infusion of the positively charged protein, protamine sulfate, the reverse was observed with mPF4+/– and mPF4–/– animals having improved thrombosis, with the hPF4+ animals having worsened thrombus formation. These studies support an important role for PF4 in thrombosis, and show that neutralization of PF4 is an important component of heparin's anticoagulant effect. The mechanisms underlying these observations of PF4 biology and their clinical implications remain to be determined.

Download Full-text