scholarly journals Desmin mediates TNF-α–induced aggregate formation and intercalated disk reorganization in heart failure

2008 ◽  
Vol 181 (5) ◽  
pp. 761-775 ◽  
Author(s):  
Panagiota Panagopoulou ◽  
Constantinos H. Davos ◽  
Derek J. Milner ◽  
Emily Varela ◽  
JoAnn Cameron ◽  
...  

We explored the involvement of the muscle-specific intermediate filament protein desmin in the model of tumor necrosis factor α (TNF-α)–induced cardiomyopathy. We demonstrate that in mice overexpressing TNF-α in the heart (α–myosin heavy chain promoter-driven secretable TNF-α [MHCsTNF]), desmin is modified, loses its intercalated disk (ID) localization, and forms aggregates that colocalize with heat shock protein 25 and ubiquitin. Additionally, other ID proteins such as desmoplakin and β-catenin show similar localization changes in a desmin-dependent fashion. To address underlying mechanisms, we examined whether desmin is a substrate for caspase-6 in vivo as well as the implications of desmin cleavage in MHCsTNF mice. We generated transgenic mice with cardiac-restricted expression of a desmin mutant (D263E) and proved that it is resistant to caspase cleavage in the MHCsTNF myocardium. The aggregates are diminished in these mice, and D263E desmin, desmoplakin, and β-catenin largely retain their proper ID localization. Importantly, D263E desmin expression attenuated cardiomyocyte apoptosis, prevented left ventricular wall thinning, and improved the function of MHCsTNF hearts.

2003 ◽  
Vol 284 (3) ◽  
pp. H960-H969 ◽  
Author(s):  
Andrzej M. Janczewski ◽  
Toshiaki Kadokami ◽  
Bonnie Lemster ◽  
Carole S. Frye ◽  
Charles F. McTiernan ◽  
...  

Transgenic (TG) TNF1.6 mice, which cardiac specifically overexpress tumor necrosis factor-α (TNF-α), exhibit heart failure (HF) and increased mortality, which is markedly higher in young (<20 wk) males (TG-M) than females (TG-F). HF in this model may be partly caused by remodeling of the extracellular matrix and/or structure/function alterations at the single myocyte level. We studied left ventricular (LV) structure and function using echocardiography and LV myocyte morphometry, contractile function, and intracellular Ca2+ (Ca[Formula: see text]) handling using cell edge detection and fura 2 fluorescence, respectively, in 12-wk-old TG-M and TG-F mice and their wild-type (WT) littermates. TG-F mice showed LV hypertrophy without dilatation and only a small reduction of basal fractional shortening (FS) and response to isoproterenol (Iso). TG-M mice showed a large LV dilatation, higher mRNA levels of β-myosin heavy chain and atrial natriuretic factor versus TG-F mice, reduced FS relative to both WT and TG-F mice, and minimal response to Iso. TG-F and TG-M myocytes were similarly elongated (by ≈20%). The amplitude of Ca[Formula: see text] transients and contractions and the response to Iso were comparable in WT and TG-F myocytes, whereas the time to 50% decline (TD50%) of the Ca[Formula: see text]transient, an index of the rate of sarcoplasmic reticulum Ca2+ uptake, was prolonged in TG-F myocytes. In TG-M myocytes, the amplitudes of Ca[Formula: see text] transients and contractions were reduced, TD50% of the Ca[Formula: see text] transient was prolonged, and the inotropic effect of Iso on Ca[Formula: see text] transients was reduced approximately twofold versus WT myocytes. Protein expression of sarco(endo)plasmic reticulum Ca2+-ATPase 2 and phospholamban was unaltered in TG versus WT hearts, suggesting functional origins of impaired Ca2+ handling in the former. These results indicate that cardiac-specific overexpression of TNF-α induces myocyte hypertrophy and gender-dependent alterations in Ca[Formula: see text] handling and contractile function, which may at least partly account for changes in LV geometry and in vivo cardiac function in this model.


2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yang Zhao ◽  
Huaxin Sun ◽  
Kai Li ◽  
Luxiang Shang ◽  
Xiaoyan Liang ◽  
...  

Background. Cholinergic anti-inflammatory pathway (CAP) is implicated in cardioprotection in chronic heart failure (CHF) by downregulating inflammation response. Mitochondrial injuries play an important role in ventricular remodeling of the CHF process. Herein, we aim to investigate whether CAP elicitation prevents ventricular remodeling in CHF by protecting myocardial mitochondrial injuries and its underlying mechanisms. Methods and Results. CHF models were established by ligation of anterior descending artery for 5 weeks. Postoperative survival rats were assigned into 5 groups: the sham group (sham, n = 10 ), CHF group (CHF, n = 11 ), Vag group (CHF+vagotomy, n = 10 ), PNU group (CHF+PNU-282987 for 4 weeks, n = 11 ), and Vag+PNU group (CHF+vagotomy+PNU-282987 for 4 weeks, n = 10 ). The antiventricular remodeling effect of cholinergic elicitation was evaluated in vivo, and H9C2 cells were selected for the TNF-α gradient stimulation experiment in vitro. In vivo, CAP agitated by PNU-282987 alleviated the left ventricular dysfunction and inhibited the energy metabolism remodeling. Further, cholinergic elicitation increased myocardium ATP levels and reduced systemic inflammation. CAP induction alleviates macrophage infiltration and cardiac fibrosis, of which the effect is counteracted by vagotomy. Myocardial mitochondrial injuries were ameliorated by CAP activation, including the reserved ultrastructural integrity, declining ROS overload, reduced myocardial apoptosis, and enhanced mitochondrial fusion. In vitro, TNF-α intervention significantly exacerbated the mitochondrial damage in H9C2 cells. Conclusion. CAP elicitation effectively improves ischemic ventricular remodeling by suppressing systemic and cardiac inflammatory response, attenuating cardiac fibrosis and potentially alleviating the mitochondrial dysfunction linked to hyperinflammation reaction.


2001 ◽  
Vol 21 (15) ◽  
pp. 4856-4867 ◽  
Author(s):  
Okot Nyormoi ◽  
Zhi Wang ◽  
Dao Doan ◽  
Maribelis Ruiz ◽  
David McConkey ◽  
...  

ABSTRACT Several reports have linked activating protein 2α (AP-2α) to apoptosis, leading us to hypothesize that AP-2α is a substrate for caspases. We tested this hypothesis by examining the effects of tumor necrosis factor alpha (TNF-α) on the expression of AP-2 in breast cancer cells. Here, we provide evidence that TNF-α downregulates AP-2α and AP-2γ expression posttranscriptionally during TNF-α-induced apoptosis. Both a general caspase antagonist (zVADfmk) and a caspase 6-preferred antagonist (zVEIDfmk) inhibited TNF-α-induced apoptosis and AP-2α downregulation. In vivo tests showed that AP-2α was cleaved by caspases ahead of the DNA fragmentation phase of apoptosis. Recombinant caspase 6 cleaved AP-2α preferentially, although caspases 1 and 3 also cleaved it, albeit at 50-fold or higher concentrations. Activated caspase 6 was detected in TNF-α-treated cells, thus confirming its involvement in AP-2α cleavage. All three caspases cleaved AP-2α at asp19 of the sequence asp-arg-his-asp (DRHD19). Mutating D19 to A19abrogated AP-2α cleavage by all three caspases. TNF-α-induced cleavage of AP-2α in vivo led to AP-2α degradation and loss of DNA-binding activity, both of which were prevented by pretreatment with zVEIDfmk. AP-2α degradation but not cleavage was inhibited in vivo by PS-431 (a proteasome antagonist), suggesting that AP-2α is degraded subsequent to cleavage by caspase 6 or caspase 6-like enzymes. Cells transfected with green fluorescent protein-tagged mutant AP-2α are resistant to TNF-α-induced apoptosis, further demonstrating the link between caspase-mediated cleavage of AP-2α and apoptosis. This is the first report to demonstrate that degradation of AP-2α is a critical event in TNF-α-induced apoptosis. Since the DRHD sequence in vertebrate AP-2 is widely conserved, its cleavage by caspases may represent an important mechanism for regulating cell survival, proliferation, differentiation, and apoptosis.


Blood ◽  
1997 ◽  
Vol 89 (9) ◽  
pp. 3228-3235 ◽  
Author(s):  
A. Zakrzewicz ◽  
M. Gräfe ◽  
D. Terbeek ◽  
M. Bongrazio ◽  
W. Auch-Schwelk ◽  
...  

Abstract To characterize L-selectin–dependent cell adhesion to human vascular endothelium, human cardiac microvascular endothelial cells (HCMEC) and human coronary endothelial cells (HCEC) were isolated from explanted human hearts. The adhesion behavior of human (NALM-6) and mouse (300.19) pre-B cells transfected with cDNA encoding for human L-selectin was compared with that of the respective nontransfected cells in a flow chamber in vitro. More than 80% of the adhesion to tumor necrosis factor-α (TNF-α)–stimulated HCMEC at shear stresses <2 dyne/cm2 was L-selectin dependent and could be equally well blocked by an anti–L-selectin antibody or a L-selectin-IgG-chimera. No L-selectin dependent adhesion to HCEC could be shown. The L-selectin dependent adhesion to HCMEC was insensitive to neuraminidase, but greatly inhibited by addition of NaClO3 , which inhibits posttranslational sulfation and remained elevated for at least 24 hours of stimulation. E-selectin dependent adhesion of HL60 cells to HCMEC was blocked by neuraminidase, but not by NaClO3 and returned to control levels within 18 hours of HCMEC stimulation. It is concluded that microvascular, but not macrovascular endothelial cells express TNF-α–inducible sulfated ligand(s) for L-selectin, which differ from known L-selectin ligands, because sialylation is not required. The prolonged time course of L-selectin dependent adhesion suggests a role in sustained leukocyte recruitment into inflammatory sites in vivo.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xin Xin ◽  
Yue Jin ◽  
Xin Wang ◽  
Beiyu Cai ◽  
Ziming An ◽  
...  

The incidence of nonalcoholic steatohepatitis (NASH) is increasing worldwide. Activation of Kupffer cells (KCs) is central to the development of diet-induced NASH. We investigated whether a combination of two active chemical components, geniposide and chlorogenic acid (GC), at a specific ratio (67 : 1), ameliorates diet-induced NASH and the underlying mechanisms involved. C57BL/6J mice exposed to a high-fat and high-cholesterol (HFHC) diet containing cholesterol, choline, and high-sugar drinking water, as well as RAW264.7 cells stimulated with lipopolysaccharide (LPS) were studied. The combination exerted a therapeutic effect on HFHC-induced NASH in mice. Simultaneously, GC was found to reduce the expression of cytokines secreted by hepatic macrophages, including tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), IL-1β, IL-6, monocyte chemotactic protein 1 (MCP-1), and granulocyte-macrophage colony-stimulating factor (GM-CSF). Moreover, GC reduced the number of KCs expressing F4/80. Furthermore, TNF-α, inducible nitric oxide synthase (INOS), IL-1β, and IL-6 mRNA and TNF-α protein expression levels were suppressed upon GC treatment in RAW264.7 cells. Our findings suggest that GC has a strong anti-inflammatory effect in NASH, and this effect can be attributed to the suppression of KC activity in the liver.


2001 ◽  
Vol 195 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Mauritius Menges ◽  
Susanne Rößner ◽  
Constanze Voigtländer ◽  
Heike Schindler ◽  
Nicole A. Kukutsch ◽  
...  

Mature dendritic cells (DCs) are believed to induce T cell immunity, whereas immature DCs induce T cell tolerance. Here we describe that injections of DCs matured with tumor necrosis factor (TNF)-α (TNF/DCs) induce antigen-specific protection from experimental autoimmune encephalomyelitis (EAE) in mice. Maturation by TNF-α induced high levels of major histocompatibility complex class II and costimulatory molecules on DCs, but they remained weak producers of proinflammatory cytokines. One injection of such TNF/DCs pulsed with auto-antigenic peptide ameliorated the disease score of EAE. This could not be observed with immature DCs or DCs matured with lipopolysaccharide (LPS) plus anti-CD40. Three consecutive injections of peptide-pulsed TNF/DCs derived from wild-type led to the induction of peptide-specific predominantly interleukin (IL)-10–producing CD4+ T cells and complete protection from EAE. Blocking of IL-10 in vivo could only partially restore the susceptibility to EAE, suggesting an important but not exclusive role of IL-10 for EAE prevention. Notably, the protection was peptide specific, as TNF/DCs pulsed with unrelated peptide could not prevent EAE. In conclusion, this study describes that stimulation by TNF-α results in incompletely matured DCs (semi-mature DCs) which induce peptide-specific IL-10–producing T cells in vivo and prevent EAE.


2018 ◽  
Vol 315 (5) ◽  
pp. C653-C663 ◽  
Author(s):  
Kasin Yadunandam Anandam ◽  
Omar A. Alwan ◽  
Veedamali S. Subramanian ◽  
Padmanabhan Srinivasan ◽  
Rubina Kapadia ◽  
...  

Riboflavin (RF), is essential for normal cellular metabolism/function. Intestinal RF absorption occurs via a specific carrier-mediated process that involves the apical transporter RFVT-3 ( SLC52A3) and the basolateral RFVT-1 (SLC52A1). Previously, we characterized different cellular/molecular aspects of the intestinal RF uptake process, but nothing is known about the effect of proinflammatory cytokines on the uptake event. We addressed this issue using in vitro, ex vivo, and in vivo models. First, we determined the level of mRNA expression of the human (h)RFVT-3 and hRFVT-1 in intestinal tissue of patients with inflammatory bowel disease (IBD) and observed a markedly lower level compared with controls. In the in vitro model, exposing Caco-2 cells to tumor necrosis factor-α (TNF-α) led to a significant inhibition in RF uptake, an effect that was abrogated upon knocking down TNF receptor 1 (TNFR1). The inhibition in RF uptake was associated with a significant reduction in the expression of hRFVT-3 and -1 protein and mRNA levels, as well as in the activity of the SLC52A3 and SLC52A1 promoters. The latter effects appear to involve Sp1 and NF-κB sites in these promoters. Similarly, exposure of mouse small intestinal enteroids and wild-type mice to TNF-α led to a significant inhibition in physiological and molecular parameters of intestinal RF uptake. Collectively, these findings demonstrate that exposure of intestinal epithelial cells to TNF-α leads to inhibition in RF uptake and that this effect is mediated, at least in part, via transcriptional mechanism(s). These findings may explain the significantly low RF levels observed in patients with IBD.


1998 ◽  
Vol 275 (2) ◽  
pp. R502-R508 ◽  
Author(s):  
Xianzhong Meng ◽  
Lihua Ao ◽  
Daniel R. Meldrum ◽  
Brian S. Cain ◽  
Brian D. Shames ◽  
...  

Exogenous tumor necrosis factor-α (TNF-α) induces delayed myocardial depression in vivo but promotes rapid myocardial depression in vitro. The temporal relationship between endogenous TNF-α and endotoxemic myocardial depression is unclear, and the role of TNF-α in this myocardial disorder remains controversial. Using a rat model of endotoxemia not complicated by shock, we sought to determine 1) the temporal relationship of changes in circulating and myocardial TNF-α with myocardial depression, 2) the influences of protein synthesis inhibition or immunosuppression on TNF-α production and myocardial depression, and 3) the influence of neutralization of TNF-α on myocardial depression. Rats were treated with lipopolysaccharide (LPS, 0.5 mg/kg ip). Circulating and myocardial TNF-α increased at 1 and 2 h, whereas myocardial contractility was depressed at 4 and 6 h. Pretreatment with cycloheximide or dexamethasone abolished the increase in circulating and myocardial TNF-α and preserved myocardial contractile function. Similarly, treatment with TNF binding protein immediately after LPS prevented myocardial depression. We conclude that endogenous TNF-α mediates delayed myocardial depression in endotoxemic rats and that inhibition of TNF-α production or neutralization of TNF-α preserves myocardial contractile function in endotoxemia.


1999 ◽  
Vol 276 (2) ◽  
pp. H671-H678 ◽  
Author(s):  
David W. A. Beno ◽  
Robert E. Kimura

Previous investigators have demonstrated that the tumor necrosis factor-α (TNF-α) response to endotoxin is inhibited by exogenous corticosterone or catecholamines both in vitro and in vivo, whereas others have reported that surgical and nonsurgical stress increase the endogenous concentrations of these stress-induced hormones. We hypothesized that elevated endogenous stress hormones resultant from experimental protocols attenuated the endotoxin-induced TNF-α response. We used a chronically catheterized rat model to demonstrate that the endotoxin-induced TNF-α response is 10- to 50-fold greater in nonstressed (NS) rats compared with either surgical-stressed (SS, laparotomy) or nonsurgical-stressed (NSS, tail vein injection) models. Compared with the NS group, the SS and NSS groups demonstrated significantly lower mean peak TNF-α responses at 2 mg/kg and 6 μg/kg endotoxin [NS 111.8 ± 6.5 ng/ml and 64.3 ± 5.9 ng/ml, respectively, vs. SS 3.9 ± 1.1 ng/ml ( P < 0.01) and 1.3 ± 0.5 ng/ml ( P < 0.01) or NSS 5.2 ± 3.2 ng/ml ( P < 0.01) at 6 μg/kg]. Similarly, baseline concentrations of corticosterone and catecholamines were significantly lower in the NSS group [84.5 ± 16.5 ng/ml and 199.8 ± 26.2 pg/ml, respectively, vs. SS group 257.2 ± 35.7 ng/ml ( P< 0.01) and 467.5 ± 52.2 pg/ml ( P < 0.01) or NS group 168.6 ± 14.4 ng/ml ( P < 0.01) and 1,109.9 ± 140.7 pg/ml ( P < 0.01)]. These findings suggest that the surgical and nonsurgical stress inherent in experimental protocols increases baseline stress hormones, masking the endotoxin-induced TNF-α response. Subsequent studies of endotoxic shock should control for the effects of protocol-induced stress and should measure and report baseline concentrations of corticosterone and catecholamines.


2013 ◽  
Vol 3 (1) ◽  
pp. 6 ◽  
Author(s):  
Ted H. Elsasser ◽  
Stanislaw Kahl ◽  
Katie M. Lebold ◽  
Maret G. Traber ◽  
Jessica Shaffer ◽  
...  

While vitamin E has been used for decades in cattle diets, the principle form used traditionally is the synthetic α-isoform acetate or succinate and largely no data exist on the biological partitioning or functionality of the major naturally occurring γ- and δ-isoforms in cattle. Using tyrosine 3’-nitrated protein (pNT) as a biomarker of nitrosative cell stress, we sought to evaluate the effectiveness of short-term feeding supplementation of high content natural α-tocopherol (<em>α-T</em>, 96% α-isomer) compared to high content γ- and δ-enriched low α-content mixed tocopherol oils (<em>γ-T</em>, ~70% <em>γ-</em>, 20% δ-, &lt;5% α-isoform) to mitigate systemic and hepatic aspects of the proinflammatory response to endotoxin (LPS). Calves fed diets supplemented with <em>α-T</em>, <em>γ-T</em> for five days or no tocopherol supplement (<em>T0E</em>) were challenged with a low-level of LPS (0.25 μg/kg, iv, <em>E. coli </em>055:B5) sufficient to effect a liver nitration response. As fed,<em> α-T</em> or <em>γ-T</em> increased plasma and liver content of the respective tocopherols reflecting their relative abundance in the respective diets. Plasma or tissue mediators and biomarkers of the proinflammatory response [plasma concentrations of tumor necrosis factor-α (TNF-α, P&lt;0.001), nitrate+nitrite (NOx, P&lt;0.01), and serum amyloid A (SAA, P&lt;0.001)], and general liver content of pNT (P&lt;0.005) increased after LPS. LPS-mediated increases in TNF-α were not dif- ferent between diet treatments; both plasma NOx (P&lt;0.05) and generalized liver pNT (P&lt;0.03) responses were attenuated significantly in <em>α-T </em>and <em>γ-T versus T0E calves</em>. Plasma SAA was significantly decreased in γ-T calves at 24 h post-LPS relative to responses in <em>α-T</em> or <em>T0E </em>calves. The nitration of the mitochondrial proteins 24 h post-LPS was not only attenuated in <em>α-T</em> and <em>γ-T vs T0E</em>, but also the mitigating effect of <em>γ-T</em> on these specific nitration events was greater than that of <em>α-T </em>(P&lt;0.01). Results are consistent with the concept that short-term <em>α-T</em> or <em>γ-T</em> supplementation can effectively decrease proinflammatory liver pNT after LPS; some mitochondrial nitration targets may be better protected with prophylactic supplementation with γ-,δ-tocopherol enriched oil.


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