Induction of transcriptional activity of AP-1 and NF-κB in the gastric mucosa during aging

2000 ◽  
Vol 278 (6) ◽  
pp. G855-G865 ◽  
Author(s):  
Zhi-Qiang Xiao ◽  
Adhip P. N. Majumdar

Although aging enhances expression and tyrosine kinase activity of epidermal growth factor receptor (EGFR) in the gastric mucosa, there is no information about EGFR signaling cascades. We examined the age-related changes in mitogen-activated protein kinases (MAPKs) [extracellular signal-related kinases (ERKs), c-Jun NH2-terminal kinases (JNKs), and p38], an EGFR-induced signaling cascade, and activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) transcriptional activity in the gastric mucosa of 4- to 6-, 12- to 14-, and 22- to 24-mo-old Fischer 344 rats. AP-1 and NF-κB transcriptional activity in the gastric mucosa rose steadily with advancing age. This can be further induced by transforming growth factor-α. The age-related activation of AP-1 and NF-κB in the gastric mucosa was associated with increased levels of c-Jun, c-Fos, and p52, but not p50 or p65. Total and phosphorylated IκBα levels in the gastric mucosa were unaffected by aging. Aging was also associated with marked activation of ERKs (p42/p44) and JNK1. In contrast, aging decreased p38 MAPK activity in the gastric mucosa. Our observation of increased activation of ERKs and JNK1 in the gastric mucosa of aged rats suggests a role for these MAPKs in regulating AP-1 and NF-κB transcriptional activity. These events may be responsible for the age-related rise in gastric mucosal proliferative activity.

2011 ◽  
Vol 300 (4) ◽  
pp. G547-G553 ◽  
Author(s):  
Rene Pahl ◽  
Gabriele Brunke ◽  
Nadine Steubesand ◽  
Sabine Schubert ◽  
Martina Böttner ◽  
...  

Candida albicans resides on epithelial surfaces as part of the physiological microflora. However, under certain conditions, it may cause life-threatening infections, including Candida sepsis. We have recently shown that human β-defensins (hBDs) hBD-2 and hBD-3 are upregulated in Candida esophagitis and that this antifungal host response is distinctly regulated by NF-κB and MAPK/activator protein-1 (AP-1) pathways. Here, we show that C. albicans induces hBD-2 through an autocrine IL-1β loop and that activation of the epidermal growth factor receptor (EGFR) by endogenous transforming growth factor-α (TGF-α) is a crucial event in the induction of hBD-3. To further dissect upstream signaling events, we investigated expression of the central sheddases for EGFR ligands ADAM10 and ADAM17 in the healthy and infected esophagus. Next, we used pharmaceutical inhibitors and small-interfering RNA-mediated knock down of ADAM10 and ADAM17 to reveal that ADAM17-induced shedding of TGF-α is a crucial step in the induction of hBD-3 expression in response to Candida infection. In conclusion, we describe for the first time an autocrine IL-1β loop responsible for the induction of hBD-2 expression and an ADAM17-TGF-α-EGFR-MAPK/AP-1 pathway leading to hBD-3 upregulation in the course of a Candida infection of the esophagus.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Arne H. A. Scheu ◽  
Sheryl Y. T. Lim ◽  
Felix J. Metzner ◽  
Shabaz Mohammed ◽  
Mark Howarth

AbstractThe Neisseria meningitidis protein FrpC contains a self-processing module (SPM) undergoing autoproteolysis via an aspartic anhydride. Herein, we establish NeissLock, using a binding protein genetically fused to SPM. Upon calcium triggering of SPM, the anhydride at the C-terminus of the binding protein allows nucleophilic attack by its target protein, ligating the complex. We establish a computational tool to search the Protein Data Bank, assessing proximity of amines to C-termini. We optimize NeissLock using the Ornithine Decarboxylase/Antizyme complex. Various sites on the target (α-amine or ε-amines) react with the anhydride, but reaction is blocked if the partner does not dock. Ligation is efficient at pH 7.0, with half-time less than 2 min. We arm Transforming Growth Factor-α with SPM, enabling specific covalent coupling to Epidermal Growth Factor Receptor at the cell-surface. NeissLock harnesses distinctive protein chemistry for high-yield covalent targeting of endogenous proteins, advancing the possibilities for molecular engineering.


2004 ◽  
Vol 128 (1) ◽  
pp. 68-70
Author(s):  
Yun-Cai Cai ◽  
Victor Roggli ◽  
Eugene Mark ◽  
Philip T. Cagle ◽  
Armando E. Fraire

Abstract Background.—Growth factors such as transforming growth factor α (TGF-α) and epidermal growth factor receptor (EGFR) play an important role in cell proliferation. The immunohistochemical expression of these factors has been extensively studied in malignant tumors including mesothelioma. However, the comparative expression of these growth factors in mesothelioma and reactive mesothelial proliferations has been less well studied. Objective.—To evaluate the possible role of TGF-α and EGFR in the clinically important distinction between reactive mesothelial proliferations and malignant mesothelioma. Methods.—The expression of TGF-α and EGFR was studied in 39 cases of mesothelioma and 30 cases of reactive mesothelial proliferations by means of immunohistochemistry. Results.—Fourteen (70%) of 20 reactive mesothelial proliferations tested and 29 (76%) of 38 mesotheliomas tested expressed TGF-α. One (3%) of 30 reactive mesothelial proliferations and 17 (45%) of 39 mesotheliomas expressed EGFR. Conclusions.—These results suggest an up-regulation of EGFR in mesothelioma as compared with reactive mesothelial proliferations. This up-regulation further suggests a possible use of EGFR as an adjunct immunohistochemical test in the differential diagnosis of mesothelioma and reactive mesothelial proliferations.


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