Abstract 270: The Eya4/six1 Signalling Cascade is Activated in Acquired Heart Disease

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Tatjana Williams ◽  
Daniel Oppelt ◽  
Peter Nordbeck ◽  
Sabine Voll ◽  
Jost Schoenberger ◽  
...  

Rationale: We previously identified a mutation in the human transcriptional cofactor Eya4 as cause of familial dilated cardiomyopathy (DCM). We now provide evidence that the Eya4/Six1 signalling cascade also is crucial in acquired heart disease. Hypothesis: We hypothesize that the transcriptional complex Eya4/Six1 regulates targets relevant in normal cardiac function. We speculate it, amongst others, regulates expression of p27kip1, a known inhibitor of hypertrophy in adult cardiomyocytes, upon hypertrophic stimuli. Methods and results: We first examined the correlation of Eya4 and p27 in regards to phosphorylation and cellular distribution in failing and normal human hearts. Immunhistology revealed Eya4 is mainly distributed in the cytoplasm while p27 predominantly resides in the nucleus of healthy myocardial tissue. In sections of failing human hearts, Eya4 accumulated in the perinuclear and nuclear region; nuclear p27 levels were significantly diminished, phosphorylated p27 was evenly distributed in the cytoplasm. In a murine model of MI, IH showed Eya4 translocates in a time-dependent manner. WB analyses for p27 showed an age dependent decrease in p27 protein levels upon MI compared to control littermates. We generated transgenic mice with constitutive myocardial overexpression of Eya4 and E193. As judged by MRI, hemodynamic and morphometric analysis both transgenic mouse models developed cardiac phenotypes compared to age-matched wildtype littermates already under basal conditions in an age dependent manner. p27 expression and downstream factors were also altered in both transgenic lines as a result of Eya4, and accordingly, E193 overexpression. In summary, we provide evidence that the Eya4/Six1 signalling cascade is not only relevant in a rare version of heritable DCM but also in more common forms of acquired heart disease. Eya4/Six1 seems to regulate p27, which was shown to be an important regulator of cardiac physiology in postmitotic cardiomyocytes.

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Qin Fu ◽  
Evan Abel ◽  
Y Kevin Xiang

Introduction: Epidemiological studies have demonstrated an increased risk of heart failure in diabetics, but the mechanisms linking diabetes mellitus (DM) to heart failure remain unclear. A uniform metabolic disturbance that characterizes type 2 diabetes is hyperinsulinemia, which accelerates adverse left ventricular (LV) remodeling in pressure overload hypertrophy. Hypothesis: We hypothesize that hyperinsulinemia might affect LV contractility by directly impairing β-adrenergic receptor (βAR) signaling. Methods and Results: Insulin receptor and β 2 AR form a cell surface complex, which dissociates upon insulin stimulation in the heart and cardiomyocytes. Insulin dose-dependent significantly inhibits PKA activities induced by a βAR agonist isoproterenol, and subsequently impairs isoproterenol-induced PKA phosphorylation of phospholamban and contractile responses in myocytes. Mechanistically, insulin action is mediated via IR and β 2 AR dependent manner. Insulin induces both PKA and GRK2-mediated phosphorylation of the β 2 AR, leading to enhanced β 2 AR/Gi coupling that inhibits adenylyl cyclase-mediated cAMP production. Pretreatment with Gi inhibitor pertussis toxin abolishes the insulin-mediated impairment of β-adrenergic stimulation of cAMP signaling. Further studies reveal that chronic insulin stimulation increases phosphodiesterase 4D protein levels in cardiac myocytes, and that the expression of phosphodiesterase 4D is also increased in animal models with high fat feeding or after 2-weeks of transaortic constriction. This leads further attenuation of βAR-induced cAMP activity for contraction response. Inhibition of phosphodiesterase 4 with rolipram rescues cAMP signaling induced by isoproterenol after insulin treatment. Last, PDE4D protein levels are significantly induced in the myocardium in diabetic patients with heart disease compared to those non-diabetic patients with heart disease. Conclusions: This is the first evidence showing that hyperinsulinemia might adversely impact cardiac contractility by inhibiting βAR signaling, which is due to IR-induced β 2 AR/Gi coupling and phosphodiesterase 4 expression in the βAR signaling cascades.


1999 ◽  
Vol 276 (3) ◽  
pp. R892-R900 ◽  
Author(s):  
Janine Y. Khan ◽  
Rosario A. Rajakumar ◽  
Robert A. McKnight ◽  
Uday P. Devaskar ◽  
Sherin U. Devaskar

We examined the molecular mechanisms that mediate the developmental increase in murine whole brain 2-deoxyglucose uptake. Northern and Western blot analyses revealed an age-dependent increase in brain GLUT-1 (endothelial cell and glial) and GLUT-3 (neuronal) membrane-spanning facilitative glucose transporter mRNA and protein concentrations. Nuclear run-on experiments revealed that these developmental changes in GLUT-1 and -3 were regulated posttranscriptionally. In contrast, the mRNA and protein levels of the mitochondrially bound glucose phosphorylating hexokinase I enzyme were unaltered. However, hexokinase I enzyme activity increased in an age-dependent manner suggestive of a posttranslational modification that is necessary for enzymatic activation. Together, the postnatal increase in GLUT-1 and -3 concentrations and hexokinase I enzymatic activity led to a parallel increase in murine brain 2-deoxyglucose uptake. Whereas the molecular mechanisms regulating the increase in the three different gene products may vary, the age-dependent increase of all three constituents appears essential for meeting the increasing demand of the maturing brain to fuel the processes of cellular growth, differentiation, and neurotransmission.


Author(s):  
Hongtao Li ◽  
Peng Chen ◽  
Lei Chen ◽  
Xinning Wang

Background: Nuclear factor kappa B (NF-κB) is usually activated in Wilms tumor (WT) cells and plays a critical role in WT development. Objective: The study purpose was to screen a NF-κB inhibitor from natural product library and explore its effects on WT development. Methods: Luciferase assay was employed to assess the effects of natural chemical son NF-κB activity. CCK-8 assay was conducted to assess cell growth in response to naringenin. WT xenograft model was established to analyze the effect of naringenin in vivo. Quantitative real-time PCR and Western blot were performed to examine the mRNA and protein levels of relative genes, respectively. Results: Naringenin displayed significant inhibitory effect on NF-κB activation in SK-NEP-1 cells. In SK-NEP-1 and G-401 cells, naringenin inhibited p65 phosphorylation. Moreover, naringenin suppressed TNF-α-induced p65 phosphorylation in WT cells. Naringenin inhibited TLR4 expression at both mRNA and protein levels in WT cells. CCK-8 staining showed that naringenin inhibited cell growth of the two above WT cells in dose-and time-dependent manner, whereas Toll-like receptor 4 (TLR4) over expression partially reversed the above phenomena. Besides, naringenin suppressed WT tumor growth in dose-and time-dependent manner in vivo. Western blot found that naringenin inhibited TLR4 expression and p65 phosphorylation in WT xenograft tumors. Conclusion: Naringenin inhibits WT development viasuppressing TLR4/NF-κB signaling


Author(s):  
Mehdi Talebi ◽  
Mousa Vatanmakanian ◽  
Ali Mirzaei ◽  
Yaghoub Barfar ◽  
Maryam Hemmatzadeh ◽  
...  

Background: Platelet-rich (PRP) and Platelet-poor plasma (PPP) are widely used in research and clinical platforms mainly due to their capacities to enhance cell growth. Although short half-life (5 days) and the high price of platelet products pose challenges regarding their usage, they maintain the growth regulatory functions for weeks. Thus, we aimed to assess the supplementary values of these products in human CCRF-CEM cancer cells. Mechanistically, we also checked if the PRP/PPP treatment enhances YKL-40 expression as a known protein regulating cell growth. Methods: The PRP/PPP was prepared from healthy donors using manual stepwise centrifugation and phase separation. The viability of the cells treated with gradient PRP/PPP concentrations (2, 5, 10, and 15%) was measured by the MTT assay. The YKL-40 mRNA and protein levels were assessed using qRT-PCR and western blotting. The data were compared to FBS-treated cells. Result: Our findings revealed that the cells treated by PRP/PPP not only were morphologically comparable to those treated by FBS but also, they showed greater viability at the concentrations of 10 and 15%. Moreover, it was shown that PRP/PPP induce cell culture support, at least in part, via inducing YKL-40 expression at both mRNA and protein levels in a time- and dose-dependent manner. Conclusion: Collectively, by showing cell culture support comparable to FBS, the PRP/PPP might be used as good candidates to supplement the cancer cell culture and overcome concerns regarding the use of FBS as a non-human source in human cancer research.


2007 ◽  
Vol 117 (2) ◽  
pp. 282-284 ◽  
Author(s):  
Valerie Godfrey ◽  
Colin A.J. Farquharson ◽  
John E. Macdonald ◽  
Kok-Meng Yee ◽  
Allan D. Struthers

2021 ◽  
Vol 22 (15) ◽  
pp. 8117
Author(s):  
Nunzia D’Onofrio ◽  
Elisa Martino ◽  
Luigi Mele ◽  
Antonino Colloca ◽  
Martina Maione ◽  
...  

Understanding the mechanisms of colorectal cancer progression is crucial in the setting of strategies for its prevention. δ-Valerobetaine (δVB) is an emerging dietary metabolite showing cytotoxic activity in colon cancer cells via autophagy and apoptosis. Here, we aimed to deepen current knowledge on the mechanism of δVB-induced colon cancer cell death by investigating the apoptotic cascade in colorectal adenocarcinoma SW480 and SW620 cells and evaluating the molecular players of mitochondrial dysfunction. Results indicated that δVB reduced cell viability in a time-dependent manner, reaching IC50 after 72 h of incubation with δVB 1.5 mM, and caused a G2/M cell cycle arrest with upregulation of cyclin A and cyclin B protein levels. The increased apoptotic cell rate occurred via caspase-3 activation with a concomitant loss in mitochondrial membrane potential and SIRT3 downregulation. Functional studies indicated that δVB activated mitochondrial apoptosis through PINK1/Parkin pathways, as upregulation of PINK1, Parkin, and LC3B protein levels was observed (p < 0.0001). Together, these findings support a critical role of PINK1/Parkin-mediated mitophagy in mitochondrial dysfunction and apoptosis induced by δVB in SW480 and SW620 colon cancer cells.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ke Zhang ◽  
Zhuoying Li ◽  
Yunyang Lu ◽  
Linyi Xiang ◽  
Jiadong Sun ◽  
...  

Abstract Background The Wnt planar cell polarity (PCP) pathway is implicated in osteoarthritis (OA) both in animals and in humans. Van Gogh-like 2 (Vangl2) is a key PCP protein that is required for the orientation and alignment of chondrocytes in the growth plate. However, its functional roles in OA still remain undefined. Here, we explored the effects of Vangl2 on OA chondrocyte in vitro and further elucidated the molecular mechanism of silencing Vangl2 in Wnt5a-overexpressing OA chondrocytes. Methods Chondrocytes were treated with IL-1β (10 ng/mL) to simulate the inflammatory microenvironment of OA. The expression levels of Vangl2, Wnt5a, MMPs, and related proinflammatory cytokines were measured by RT-qPCR. Small interfering RNA (siRNA) of Vangl2 and the plasmid targeting Wnt5a were constructed and transfected into ATDC5 cells. Then, the functional roles of silencing Vangl2 in the OA chondrocytes were investigated by Western blotting, RT-qPCR, and immunocytochemistry (ICC). Transfected OA chondrocytes were subjected to Western blotting to analyze the relationship between Vangl2 and related signaling pathways. Results IL-1β induced the production of Vangl2, Wnt5a, and MMPs in a time-dependent manner and the significantly increased expression of Vangl2. Vangl2 silencing effectively suppressed the expression of MMP3, MMP9, MMP13, and IL-6 at both gene and protein levels and upregulated the expression of type II collagen and aggrecan. Moreover, knockdown of Vangl2 inhibited the phosphorylation of MAPK signaling molecules (P38, ERK, and JNK) and P65 in Wnt5a-overexpressing OA chondrocytes. Conclusions For the first time, we demonstrate that Vangl2 is involved in the OA process. Vangl2 silencing can notably alleviate OA progression in vitro by inhibiting the expression of MMPs and increasing the formation of the cartilage matrix and can inhibit the proinflammatory effects of Wnt5a via MAPK and NF-κB pathway. This study provides new insight into the mechanism of cartilage inflammation.


Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 490
Author(s):  
Xueqi Qu ◽  
Christiane Neuhoff ◽  
Mehmet Ulas Cinar ◽  
Maren Pröll ◽  
Ernst Tholen ◽  
...  

Inflammation is regulated by epigenetic modifications, including DNA methylation and histone acetylation. Sulforaphane (SFN), a histone deacetylase (HDAC) inhibitor, is also a potent immunomodulatory agent, but its anti-inflammatory functions through epigenetic modifications remain unclear. Therefore, this study aimed to investigate the epigenetic effects of SFN in maintaining the immunomodulatory homeostasis of innate immunity during acute inflammation. For this purpose, SFN-induced epigenetic changes and expression levels of immune-related genes in response to lipopolysaccharide (LPS) stimulation of monocyte-derived dendritic cells (moDCs) were analyzed. These results demonstrated that SFN inhibited HDAC activity and caused histone H3 and H4 acetylation. SFN treatment also induced DNA demethylation in the promoter region of the MHC-SLA1 gene, resulting in the upregulation of Toll-like receptor 4 (TLR4), MHC-SLA1, and inflammatory cytokines’ expression at 6 h of LPS stimulation. Moreover, the protein levels of cytokines in the cell culture supernatants were significantly inhibited by SFN pre-treatment followed by LPS stimulation in a time-dependent manner, suggesting that inhibition of HDAC activity and DNA methylation by SFN may restrict the excessive inflammatory cytokine availability in the extracellular environment. We postulate that SFN may exert a protective and anti-inflammatory function by epigenetically influencing signaling pathways in experimental conditions employing porcine moDCs.


Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1652
Author(s):  
Chinmaya Panda ◽  
Clara Voelz ◽  
Pardes Habib ◽  
Christian Mevissen ◽  
Thomas Pufe ◽  
...  

Intra-neuronal misfolding of monomeric tau protein to toxic β-sheet rich neurofibrillary tangles is a hallmark of Alzheimer’s disease (AD). Tau pathology correlates not only with progressive dementia but also with microglia-mediated inflammation in AD. Amyloid-beta (Aβ), another pathogenic peptide involved in AD, has been shown to activate NLRP3 inflammasome (NOD-like receptor family, pyrin domain containing 3), triggering the secretion of proinflammatory interleukin-1β (IL1β) and interleukin-18 (IL18). However, the effect of tau protein on microglia concerning inflammasome activation, microglial polarization, and autophagy is poorly understood. In this study, human microglial cells (HMC3) were stimulated with the unaggregated and aggregated forms of the tau-derived PHF6 peptide (VQIVYK). Modulation of NLRP3 inflammasome was examined by qRT-PCR, immunocytochemistry, and Western blot. We demonstrate that fibrillar aggregates of VQIVYK upregulated the NLRP3 expression at both mRNA and protein levels in a dose- and time-dependent manner, leading to increased expression of IL1β and IL18 in HMC3 cells. Aggregated PHF6-peptide also activated other related inflammation and microglial polarization markers. Furthermore, we also report a time-dependent effect of the aggregated PHF6 on BECN1 (Beclin-1) expression and autophagy. Overall, the PHF6 model system-based study may help to better understand the complex interconnections between Alzheimer’s PHF6 peptide aggregation and microglial inflammation, polarization, and autophagy.


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