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The inhibitory Smad7 acts as a critical suppressor of hepcidin, the major regulator of systemic iron homeostasis. In this study we define the mRNA expression of the two functionally related Smad proteins, Smad6 and Smad7, within pathways known to regulate hepcidin levels. Using mouse models for hereditary hemochromatosis (Hfe-, TfR2-, Hfe/TfR2-, Hjv- and hepcidin1-deficient mice) we show that hepcidin, Smad6 and Smad7 mRNA expression is coordinated in such a way that it correlates with the activity of the Bmp/Smad signaling pathway rather than with liver iron levels. This regulatory circuitry is disconnected by iron treatment of Hfe-/- and Hfe/TfR2 mice that significantly increases hepatic iron levels as well as hepcidin, Smad6 and Smad7 mRNA expression but fails to augment pSmad1/5/8 levels. This suggests that additional pathways contribute to the regulation of hepcidin, Smad6 and Smad7 under these conditions which do not require Hfe.
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http://dx.doi.org/10.1016/j.bbadis.2012.08.013 | DOI Listing |
bioRxiv
June 2025
Biology Department, Southern Connecticut State University, New Haven, USA.
Inhibitory Smads (I-Smads) regulate TGF-β/BMP signaling through multiple distinct mechanisms, but whether different tissues preferentially employ specific mechanisms remains unknown. To address this question, we performed structure-function analyses of the I-Smad Dad and its vertebrate orthologs Smad6 and Smad7 in neural and wing tissues, measuring in vivo outputs of BMP signaling. We identified a critical 24-amino acid putative DNA-binding domain (DNABD) within the MH1 domain of the I-Smad, Dad, that is essential for inhibitory function in wing tissue but unessential in neural tissue.
View Article and Find Full Text PDFInt J Mol Sci
March 2025
Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Kyung Hee University Medical Center, Kyung Hee University, Seoul 02447, Republic of Korea.
Facial nerve injury can lead to significant functional impairment, emotional impacts, and difficulties in social and economic activities. Although peripheral nerves have the potential for recovery, incomplete regeneration can pose challenges. Suppressor of Mothers Against Decapentaplegic Homolog (SMAD) proteins are crucial in the nerve-regeneration process.
View Article and Find Full Text PDFEur J Pharmacol
February 2025
School of Health Sciences and Technology (SoHST), UPES, Dehradun, Uttarakhand, 248007, India. Electronic address:
The intricate regulatory mechanisms governing TGF-β1 expression play pivotal roles in tumor progression. Key proteins such as FKBP1A, SMAD6, and SMAD7 trigger this process, modulating cell growth inhibition via p15INK4b and p21CIP1 induction. Despite TGF-β's tumor-suppressive functions, cancer cells adeptly evade its effects, fueling disease advancement.
View Article and Find Full Text PDFCurr Issues Mol Biol
July 2024
Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Kyung Hee University Medical Center, Kyung Hee University, Seoul 02447, Republic of Korea.
Sci Rep
March 2024
Department of Anesthesiology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China.
Breast cancer is a serious threat to human health. The transforming growth factor-β signaling pathway is an important pathway involved in the occurrence and development of cancer. The SMAD family genes are responsible for the TGF-β signaling pathway.
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