Differential Effects of Prenatal Stress in Female 5-Htt-Deficient Mice: Towards Molecular Mechanisms of Resilience

Background. Intestinal barrier injury is an important contributor to many diseases. We previously found that heme oxygenase-1 (HO-1) and carbon monoxide (CO) protect the intestinal barrier. This study is aimed at elucidating the molecular mechanisms of HO-1/CO in barrier loss. Materials and Methods. We induced gut leakiness by injecting carbon tetrachloride (CCl4) to wildtype or intestinal HO-1-deficient mice. In addition, we administrated tumor necrosis factor-α (TNF-α) to cells with gain- or loss-of-HO-1 function. The effects of HO-1/CO maintaining intestinal barrier integrity were investigated in vivo and in vitro. Results. Cobalt protoporphyrin and CO-releasing molecule-2 alleviated colonic mucosal injury and TNF-α levels; upregulated tight junction (TJ) expression; and inhibited epithelial IκB-α degradation and phosphorylation, NF-κB p65 phosphorylation, long MLCK expression, and MLC-2 phosphorylation after administration of CCl4. Zinc protoporphyrin completely reversed these effects. These findings were further confirmed in vitro, using Caco-2 cells with gain- or loss-of-HO-1-function after TNF-α. Pretreated with JSH-23 (NF-κB inhibitor) or ML-7 (long MLCK inhibitor), HO-1 overexpression prevented TNF-α-induced TJ disruption, while HO-1 shRNA promoted TJ damage even in the presence of JSH-23 or ML-7, thus suggesting that HO-1 dependently protected intestinal barrier via the NF-κB p65/MLCK/p-MLC-2 pathway. Intestinal HO-1-deficient mice further demonstrated the effects of HO-1 in maintaining intestinal barrier integrity and its relative mechanisms. Alleviated hepatic fibrogenesis and serum ALT levels finally confirmed the clinical significance of HO-1/CO repairing barrier loss in liver injury. Conclusion. HO-1/CO maintains intestinal barrier integrity through the NF-κB/MLCK pathway. Therefore, the intestinal HO-1/CO-NF-κB/MLCK system is a potential therapeutic target for diseases with a leaky gut.

Download Full-text

Olfactomedin 4 contributes to hydrogen peroxide-induced NADPH oxidase activation and apoptosis in mouse neutrophils

AJP Cell Physiology ◽

10.1152/ajpcell.00336.2017 ◽

2018 ◽

Vol 315 (4) ◽

pp. C494-C501 ◽

Cited By ~ 3

Author(s):

Wenli Liu ◽

Yueqin Liu ◽

Hongzhen Li ◽

Griffin P. Rodgers

Keyword(s):

Hydrogen Peroxide ◽

Nadph Oxidase ◽

Molecular Mechanisms ◽

Oxidase Inhibitor ◽

Superoxide Production ◽

Wild Type ◽

Escherichia Coli Bacteria ◽

Induced Apoptosis ◽

Nadph Oxidase Activation ◽

Deficient Mice

Neutrophils increase production of reactive oxygen species, including superoxide, hydrogen peroxide (H2O2), and hydroxyl radical, to destroy invading microorganisms under pathological conditions. Conversely, oxidative stress conditions, such as the presence of H2O2, induce neutrophil apoptosis, which helps to remove neutrophils after inflammation. However, the detailed molecular mechanisms that are involved in the latter process have not been elucidated. In this study, we investigated the potential role of olfactomedin 4 (Olfm4) in H2O2-induced superoxide production and apoptosis in mouse neutrophils. We have demonstrated that Olfm4 is not required for maximal-dosage PMA- and Escherichia coli bacteria-induced superoxide production, but Olfm4 contributes to suboptimal-dosage PMA- and H2O2-induced superoxide production. Using an NADPH oxidase inhibitor and gp91phox-deficient mouse neutrophils, we found that NAPDH oxidase was required for PMA-stimulated superoxide production and that Olfm4 mediated H2O2-induced superoxide production through NADPH oxidase, in mouse neutrophils. We have shown that neutrophils from Olfm4-deficient mice exhibited reduced H2O2-induced apoptosis compared with neutrophils from wild-type mice. We also demonstrated that neutrophils from Olfm4-deficient mice exhibited reduced H2O2-stimulated mitochondrial damage and membrane permeability, and as well as reduced caspase-3 and caspase-9 activity, compared with neutrophils from wild-type mice. Moreover, the cytoplasmic translocation of the proapoptotic mitochondrial proteins Omi/HtrA2 and Smac/DIABLO in response to H2O2was reduced in neutrophils from Olfm4-deficient mice compared with neutrophils from wild-type mice. Our study demonstrates that Olfm4 contributes to H2O2-induced NADPH oxidase activation and apoptosis in mouse neutrophils. Olfactomedin 4 might prove to be a potential target for future studies on inflammatory neutrophil biology and for inflammatory disease treatment.

Download Full-text

Abstract 353: Chronic Polarization of Low-grade Inflammatory Monocytes During the Pathogenesis of Atherosclerosis

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.353 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Liwu Li ◽

Shuo Geng

Keyword(s):

High Fat Diet ◽

Immunohistochemical Staining ◽

Molecular Mechanisms ◽

Molecular Switches ◽

Low Grade ◽

High Fat ◽

Inflammatory Monocytes ◽

Severe Atherosclerosis ◽

Low Grade Inflammation ◽

Deficient Mice

Background: Chronic inflammation mediated by low-grade inflammatory monocytes may serve as a key culprit for atherosclerosis. However, the cellular and molecular mechanisms responsible for the low-grade inflammatory polarization of monocytes are not well understood. We hypothesize that the selective clearance of homeostatic molecular switches may pre-dispose innate monocytes for the establishment of non-resolving low-grade inflammation. Methods and Results: By comparing high-fat-diet (HFD) fed ApoE deficient mice chronically challenged with either PBS or a subclinical dose endotoxin, we observed that subclinical endotoxin potently induced the establishment of low-grade inflammation, as manifested in elevated levels of systemic inflammatory mediators, accumulation of low-grade inflammatory circulating monocytes and neutrophils, as well as lipids. Immunohistochemical staining of liver and aorta tissues revealed significantly elevated steatosis and atherosclerosis in ApoE deficient mice chronically challenged with subclinical dose of endotoxin. At the mechanistic level, the polarization of low-grade inflammatory monocytes were due to the down-regulation and removal of key homeostatic molecules such as IRAK-M and Tollip. ApoE and IRAK-M double deficient mice had enhanced inflammatory polarization of innate monocytes, and developed severe atherosclerosis. Conclusions: Our data suggest that the clearance of homeostatic suppressors such as IRAK-M and Tollip may cause the memory establishment of low-grade inflammatory monocytes that are conducive for the chronic pathogenesis of atherosclerosis. Key words: Low-grade inflammation, monocyte polarization, innate memory, atherosclerosis

Download Full-text

Abstract 263: Differential Effects of 17ß-Estradiol and 16a-Hydroxyestrone in Oxidative Stress and Proliferative Responses in Human Pulmonary Artery Smooth Muscle Cells - Implications in Pulmonary Arterial Hypertension

Hypertension ◽

10.1161/hyp.62.suppl_1.a263 ◽

2013 ◽

Vol 62 (suppl_1) ◽

Author(s):

Katie Y Hood ◽

Augusto C Montezano ◽

Margaret R MacLean ◽

Rhian M Touyz

Keyword(s):

Oxidative Stress ◽

Pulmonary Arterial Hypertension ◽

Cell Growth ◽

Arterial Hypertension ◽

Molecular Mechanisms ◽

Antioxidant Systems ◽

Ros Generation ◽

Ros Production ◽

Differential Effects ◽

Pulmonary Arterial

Women develop pulmonary arterial hypertension (PAH) more frequently than men. This may relate, in part, to metabolism of 17β-estradiol (E2), leading to formation of the deleterious metabolite, 16α-hydroxyestrone (16α OHE1), which plays a role in the remodelling of pulmonary arteries. Molecular mechanisms whereby 16αOHE1 influences PASMC remodelling are unclear but ROS may be important, since oxidative stress has been implicated in the pathogenesis of PAH. We hypothesised that E2 and 16αOHE1 leads to Nox-induced ROS production, which promotes PASMC damage. Cultured PASMCs were stimulated with either E2 (1nM) or 16αOHE1 (1nM) in the presence/absence of EHT1864 (100μM, Rac1 inhibitor) or tempol (antioxidant; 10μM). ROS production was assessed by chemiluminescence (O2-) and Amplex Red (H2O2). Antioxidants (thioredoxin, peroxiredoxin 1 and NQ01), regulators of Nrf2 (BACH1, Nrf2) and, marker of cell growth (PCNA) were determined by immunoblotting. E2 increased O2- production at 4h (219 ± 30% vs vehicle; p<0.05), an effect blocked by EHT1864 and tempol. E2 also increased H2O2 generation (152 ± 4%; p<0.05). Thioredoxin, NQ01 and peroxiredoxin1 (71 ± 6%; 78 ± 9%; 69 ± 8%; p<0.05 respectively) levels were decreased by E2 as was PCNA expression (72 ± 2%; p<0.05). 16αOHE1 exhibited a rapid (5 min) and exaggerated increase in ROS production (355 ± 41%; p<0.05), blocked by tempol and EHT1864. This was associated with an increase in Nox4 expression (139 ± 11% vs vehicle, p<0.05). 16αOHE1 increased BACH1, (129 ± 3%; p<0.05), a competitor of Nrf2, which was decreased (92 ± 2%). In contrast, thioredoxin expression was increased by 16aOHE1 (154 ± 22%; p<0.05). PCNA (150 ± 5%) expression was also increased after exposure to 16αOHE1. In conclusion, E2 and 16αOHE1 have differential effects on redox processes associated with PASMC growth. Whereas E2 stimulates ROS production in a slow and sustained manner without effect on cell growth, 16αOHE1 upregulates Nox4 with associated rapid increase in ROS generation and downregulation of antioxidant systems, affecting proliferation. Our findings suggest that E2 -derived metabolites may promote a pro-proliferative PASMC phenotype through Nox4-derived ROS generation. These deleterious effects may impact on vascular remodeling in PAH.

Download Full-text

TAK1 deficiency attenuates cisplatin-induced acute kidney injury

AJP Renal Physiology ◽

10.1152/ajprenal.00516.2019 ◽

2020 ◽

Vol 318 (1) ◽

pp. F209-F215 ◽

Cited By ~ 2

Author(s):

Jun Zhou ◽

Changlong An ◽

Xiaogao Jin ◽

Zhaoyong Hu ◽

Robert L. Safirstein ◽

...

Keyword(s):

Acute Kidney Injury ◽

Proximal Tubule ◽

Molecular Mechanisms ◽

Transforming Growth Factor ◽

Kidney Injury ◽

Transforming Growth Factor Β ◽

Tubular Epithelial Cell ◽

Tubular Damage ◽

Wild Type ◽

Deficient Mice

Cisplatin can cause acute kidney injury (AKI), but the molecular mechanisms are not well understood. The objective of the present study was to examine the role of transforming growth factor-β-activated kinase-1 (TAK1) in the pathogenesis of cisplatin-induced AKI. Wild-type mice and proximal tubule TAK1-deficient mice were treated with vehicle or cisplatin. Compared with wild-type control mice, proximal tubule TAK1-deficient mice had less severe kidney dysfunction, tubular damage, and apoptosis after cisplatin–induced AKI. Furthermore, conditional disruption of TAK1 in proximal tubular epithelial cells reduced caspase-3 activation, proinflammatory molecule expression, and JNK phosphorylation in the kidney in cisplatin-induced AKI. Taken together, cisplatin activates TAK1-JNK signaling pathway to promote tubular epithelial cell apoptosis and inflammation in cisplatin-induced AKI. Targeting TAK1 could be a novel therapeutic strategy against cisplatin-induced AKI.

Download Full-text

Immune Relevant and Immune Deficient Mice: Options and Opportunities in Translational Research

ILAR Journal ◽

10.1093/ilar/ily026 ◽

2018 ◽

Vol 59 (3) ◽

pp. 211-246

Author(s):

Enrico Radaelli ◽

Sara F Santagostino ◽

Rani S Sellers ◽

Cory F Brayton

Keyword(s):

Translational Research ◽

Reproducibility Of Results ◽

Molecular Mechanisms ◽

Genetic Variations ◽

Mouse Strains ◽

Spontaneous Mutations ◽

Deficient Mice

Abstract In 1989 ILAR published a list and description of immunodeficient rodents used in research. Since then, advances in understanding of molecular mechanisms; recognition of genetic, epigenetic microbial, and other influences on immunity; and capabilities in manipulating genomes and microbiomes have increased options and opportunities for selecting mice and designing studies to answer important mechanistic and therapeutic questions. Despite numerous scientific breakthroughs that have benefitted from research in mice, there is debate about the relevance and predictive or translational value of research in mice. Reproducibility of results obtained from mice and other research models also is a well-publicized concern. This review summarizes resources to inform the selection and use of immune relevant mouse strains and stocks, aiming to improve the utility, validity, and reproducibility of research in mice. Immune sufficient genetic variations, immune relevant spontaneous mutations, immunodeficient and autoimmune phenotypes, and selected induced conditions are emphasized.

Download Full-text