ANG II stimulates PKC-dependent ERK activation, DNA synthesis, and cell division in intestinal epithelial cells

2003 ◽  
Vol 285 (1) ◽  
pp. G1-G11 ◽  
Author(s):  
Terence Chiu ◽  
Chintda Santiskulvong ◽  
Enrique Rozengurt

PKC, a major target for the tumor-promoting phorbol esters, has been implicated in the signal transduction pathways that mediate important functions in intestinal epithelial cells, including proliferation and carcinogenesis. With the use of IEC-18 cells arrested in G0/G1, addition of phorbol esters resulted in a modest increase in [3H]thymidine incorporation and a slight shift toward the S and G2/M phases of the cell cycle, whereas the combination of EGF and phorbol 12,13-dibutyrate (PDB) synergistically stimulated DNA synthesis. To investigate the effects of receptor-mediated PKC activation on mitogenesis, we demonstrated that ANG II induced ERK activation, a response completely blocked by pretreatment with mitogen/extracellular signal-regulated kinase inhibitors or specific PKC inhibitors. Furthermore, ANG II stimulated an over threefold increase in [3H]thymidine incorporation that was corroborated by flow cytometric analysis of the cell cycle to levels comparable to that achieved by the combination of EGF and PDB. Taken together, our results indicate that receptor-mediated PKC activation, as induced by ANG II, transduces mitogenic signals leading to DNA synthesis and cell proliferation in IEC-18 cells.

2014 ◽  
Vol 306 (10) ◽  
pp. C961-C971 ◽  
Author(s):  
James Sinnett-Smith ◽  
Yang Ni ◽  
Jia Wang ◽  
Ming Ming ◽  
Steven H. Young ◽  
...  

We examined whether class IIa histone deacetylases (HDACs) play a role in mitogenic signaling mediated by protein kinase D1 (PKD1) in IEC-18 intestinal epithelial cells. Our results show that class IIa HDAC4, HDAC5, and HDAC7 are prominently expressed in these cells. Stimulation with ANG II, a potent mitogen for IEC-18 cells, induced a striking increase in phosphorylation of HDAC4 at Ser246 and Ser632, HDAC5 at Ser259 and Ser498, and HDAC7 at Ser155. Treatment with the PKD family inhibitors kb NB 142-70 and CRT0066101 or small interfering RNA-mediated knockdown of PKD1 prevented ANG II-induced phosphorylation of HDAC4, HDAC5, and HDAC7. A variety of PKD1 activators in IEC-18 cells, including vasopressin, lysophosphatidic acid, and phorbol esters, also induced HDAC4, HDAC5, and HDAC7 phosphorylation. Using endogenously and ectopically expressed HDAC5, we show that PKD1-mediated phosphorylation of HDAC5 induces its nuclear extrusion into the cytoplasm. In contrast, HDAC5 with Ser259 and Ser498 mutated to Ala was localized to the nucleus in unstimulated and stimulated cells. Treatment of IEC-18 cells with specific inhibitors of class IIa HDACs, including MC1568 and TMP269, prevented cell cycle progression, DNA synthesis, and proliferation induced in response to G protein-coupled receptor/PKD1 activation. The PKD1-class IIa HDAC axis also functions in intestinal epithelial cells in vivo, since an increase in phosphorylation of HDAC4/5 and HDAC7 was demonstrated in lysates of crypt cells from PKD1 transgenic mice compared with matched nontransgenic littermates. Collectively, our results reveal a PKD1-class IIa HDAC axis in intestinal epithelial cells leading to mitogenic signaling.


Marine Drugs ◽  
2019 ◽  
Vol 17 (4) ◽  
pp. 205
Author(s):  
Su-Jin Jeong ◽  
Jeong-Wook Choi ◽  
Min-Kyeong Lee ◽  
Youn-Hee Choi ◽  
Taek-Jeong Nam

Spirulina is a type of filamentous blue-green microalgae known to be rich in nutrients and to have pharmacological effects, but the effect of spirulina on the small intestine epithelium is not well understood. Therefore, this study aims to investigate the proliferative effects of spirulina crude protein (SPCP) on a rat intestinal epithelial cells IEC-6 to elucidate the mechanisms underlying its effect. First, the results of wound-healing and cell viability assays demonstrated that SPCP promoted migration and proliferation in a dose-dependent manner. Subsequently, when the mechanisms of migration and proliferation promotion by SPCP were confirmed, we found that the epidermal growth factor receptor (EGFR) and mitogen-activated protein (MAPK) signaling pathways were activated by phosphorylation. Cell cycle progression from G0/G1 to S phase was also promoted by SPCP through upregulation of the expression levels of cyclins and cyclin-dependent kinases (Cdks), which regulate cell cycle progression to the S phase. Meanwhile, the expression of cyclin-dependent kinase inhibitors (CKIs), such as p21 and p27, decreased with SPCP. In conclusion, our results indicate that activation of EGFR and its downstream signaling pathway by SPCP treatment regulates cell cycle progression. Therefore, these results contribute to the research on the molecular mechanism for SPCP promoting the migration and proliferation of rat intestinal epithelial cells.


2016 ◽  
Vol 310 (7) ◽  
pp. C542-C557 ◽  
Author(s):  
Jia Wang ◽  
Liang Han ◽  
James Sinnett-Smith ◽  
Li-Li Han ◽  
Jan V. Stevens ◽  
...  

Given the fundamental role of β-catenin signaling in intestinal epithelial cell proliferation and the growth-promoting function of protein kinase D1 (PKD1) in these cells, we hypothesized that PKDs mediate cross talk with β-catenin signaling. The results presented here provide several lines of evidence supporting this hypothesis. We found that stimulation of intestinal epithelial IEC-18 cells with the G protein-coupled receptor (GPCR) agonist angiotensin II (ANG II), a potent inducer of PKD activation, promoted endogenous β-catenin nuclear localization in a time-dependent manner. A significant increase was evident within 1 h of ANG II stimulation ( P < 0.01), peaked at 4 h ( P < 0.001), and declined afterwards. GPCR stimulation also induced a marked increase in β-catenin-regulated genes and phosphorylation at Ser552 in intestinal epithelial cells. Exposure to preferential inhibitors of the PKD family (CRT006610 or kb NB 142-70) or knockdown of the isoforms of the PKD family prevented the increase in β-catenin nuclear localization and phosphorylation at Ser552 in response to ANG II. GPCR stimulation also induced the formation of a complex between PKD1 and β-catenin, as shown by coimmunoprecipitation that depended on PKD1 catalytic activation, as it was abrogated by cell treatment with PKD family inhibitors. Using transgenic mice that express elevated PKD1 protein in the intestinal epithelium, we detected a marked increase in the localization of β-catenin in the nucleus of crypt epithelial cells in the ileum of PKD1 transgenic mice, compared with nontransgenic littermates. Collectively, our results identify a novel cross talk between PKD and β-catenin in intestinal epithelial cells, both in vitro and in vivo.


Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 707-707
Author(s):  
Quy N Diep ◽  
Mohammed El Mabrouk ◽  
Rhian M Touyz ◽  
Ernesto L Schiffrin

P79 Angiotensin II (Ang II) is an important modulator of cell growth via AT 1 receptors, as demonstrated both in vivo and in vitro . Here, we investigated the role of different proteins involved in the cell cycle, including cyclin D1, cyclin-dependent kinase 4 (cdk4) and cdk inhibitors p21 and p27 in blood vessels of Ang II-infused rats and the effect therein of the AT 1 receptor antagonist losartan. Male Sprague Dawley rats were infused for 7 days with Ang II (120 ng/kg/min s.c.) and/or treated with losartan (10 mg/kg/day orally). DNA synthesis in mesenteric arteries was evaluated by radiolabeled 3 H-thymidine incorporation. The expression of p21, p27, cyclin D1, cdk4 and E2F, which play critical roles during G1-phase of the cell cycle process, was examined by Western blot analysis. Tail cuff systolic blood pressure (mmHg) was elevated (p<0.05, n=9) in Ang II-infused rats (161.3±8.2) vs. controls (110.1±5.3) and normalized by losartan (104.4±3.2). Radiolabeled 3 H-thymidine incorporation (cpm/100 μg DNA) showed that Ang II-infusion significantly increased DNA synthesis (152±5 vs. 102±6, p<0.05). Expression of p21 and p27 was significantly decreased in the Ang II group to 23.2±10.4% and 10.3±5.3% of controls, respectively, whereas expression of cyclin D1 and cdk4 was significantly increased in the Ang II group to 213.7±8% and 263.6±37% of controls, respectively. These effects induced by Ang II infusion was normalized in the presence of losartan. Ang II had no effect on the expression of E2F. Thus, when AT 1 receptors are stimulated in vivo , DNA synthesis is enhanced in blood vessels by activation of cyclin D1 and cdk4. Reduction in cell cycle kinase inhibitors p21 and p27 may contribute to activation of growth induced by in vivo AT 1 receptor stimulation.


2003 ◽  
Vol 279 (10) ◽  
pp. 9233-9247 ◽  
Author(s):  
Jennifer A. Clark ◽  
Adrian R. Black ◽  
Olga V. Leontieva ◽  
Mark R. Frey ◽  
Marybeth A. Pysz ◽  
...  

PLoS ONE ◽  
2012 ◽  
Vol 7 (12) ◽  
pp. e52869 ◽  
Author(s):  
Malgorzata Nepelska ◽  
Antonietta Cultrone ◽  
Fabienne Béguet-Crespel ◽  
Karine Le Roux ◽  
Joël Doré ◽  
...  

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