SMAD7 controls iron metabolism as a potent inhibitor of hepcidin expression

Blood ◽  
2010 ◽  
Vol 115 (13) ◽  
pp. 2657-2665 ◽  
Author(s):  
Katarzyna Mleczko-Sanecka ◽  
Guillem Casanovas ◽  
Anan Ragab ◽  
Katja Breitkopf ◽  
Alexandra Müller ◽  
...  
Keyword(s):  
Growth Factor ◽  
Iron Metabolism ◽  
Negative Feedback ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Bmp Signaling ◽  
Hepcidin Expression ◽  
Morphogenetic Protein ◽  
Smad Protein

Abstract Hepcidin is the master regulatory hormone of systemic iron metabolism. Hepcidin deficiency causes common iron overload syndromes whereas its overexpression is responsible for microcytic anemias. Hepcidin transcription is activated by the bone morphogenetic protein (BMP) and the inflammatory JAK-STAT pathways, whereas comparatively little is known about how hepcidin expression is inhibited. By using high-throughput siRNA screening we identified SMAD7 as a potent hepcidin suppressor. SMAD7 is an inhibitory SMAD protein that mediates a negative feedback loop to both transforming growth factor-β and BMP signaling and that recently was shown to be coregulated with hepcidin via SMAD4 in response to altered iron availability in vivo. We show that SMAD7 is coregulated with hepcidin by BMPs in primary murine hepatocytes and that SMAD7 overexpression completely abolishes hepcidin activation by BMPs and transforming growth factor-β. We identify a distinct SMAD regulatory motif (GTCAAGAC) within the hepcidin promoter involved in SMAD7-dependent hepcidin suppression, demonstrating that SMAD7 does not simply antagonize the previously reported hemojuvelin/BMP-responsive elements. This work identifies a potent inhibitory factor for hepcidin expression and uncovers a negative feedback pathway for hepcidin regulation, providing insight into a mechanism how hepcidin expression may be limited to avoid iron deficiency.

scholarly journals Reovirus Activates Transforming Growth Factor β and Bone Morphogenetic Protein Signaling Pathways in the Central Nervous System That Contribute to Neuronal Survival following Infection

2009 ◽  
Vol 83 (10) ◽  
pp. 5035-5045 ◽  
Author(s):  
J. David Beckham ◽  
Kathryn Tuttle ◽  
Kenneth L. Tyler
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Signaling Pathways ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Bmp Signaling ◽  
Downstream Signaling ◽  
Morphogenetic Protein ◽  
The Central Nervous System

ABSTRACT Viral infections of the central nervous system (CNS) are important causes of worldwide morbidity and mortality, and understanding how viruses perturb host cell signaling pathways will facilitate identification of novel antiviral therapies. We now show that reovirus infection activates transforming growth factor β (TGF-β) and bone morphogenetic protein (BMP) signaling in a murine model of encephalitis in vivo. TGF-β receptor I (TGF-βRI) expression is increased and its downstream signaling factor, SMAD3, is activated in the brains of reovirus-infected mice. TGF-β signaling is neuroprotective, as inhibition with a TGF-βRI inhibitor increases death of infected neurons. Similarly, BMP receptor I expression is increased and its downstream signaling factor, SMAD1, is activated in reovirus-infected neurons in the brains of infected mice in vivo. Activated SMAD1 and SMAD3 were both detected in regions of brain infected by reovirus, but activated SMAD1 was found predominantly in uninfected neurons in close proximity to infected neurons. Treatment of reovirus-infected primary mouse cortical neurons with a BMP agonist reduced apoptosis. These data provide the first evidence for the activation of TGF-β and BMP signaling pathways following neurotropic viral infection and suggest that these signaling pathways normally function as part of the host's protective innate immune response against CNS viral infection.

scholarly journals GDF11 promotes osteogenesis as opposed to MSTN, and follistatin, a MSTN/GDF11 inhibitor, increases muscle mass but weakens bone

2020 ◽  
Vol 117 (9) ◽  
pp. 4910-4920 ◽  
Author(s):  
Joonho Suh ◽  
Na-Kyung Kim ◽  
Seung-Hoon Lee ◽  
Je-Hyun Eom ◽  
Youngkyun Lee ◽  
...  
Keyword(s):  
Bone Mass ◽  
Muscle Mass ◽  
Transforming Growth Factor ◽  
Bone Fractures ◽  
Muscle Growth ◽  
Transforming Growth Factor Β ◽  
Biochemical Properties ◽  
Bmp Signaling ◽  
Morphogenetic Protein ◽  
Perinatal Lethality

Growth and differentiation factor 11 (GDF11) and myostatin (MSTN) are closely related transforming growth factor β (TGF-β) family members, but their biological functions are quite distinct. While MSTN has been widely shown to inhibit muscle growth, GDF11 regulates skeletal patterning and organ development during embryogenesis. Postnatal functions of GDF11, however, remain less clear and controversial. Due to the perinatal lethality ofGdf11null mice, previous studies used recombinant GDF11 protein to prove its postnatal function. However, recombinant GDF11 and MSTN proteins share nearly identical biochemical properties, and most GDF11-binding molecules have also been shown to bind MSTN, generating the possibility that the effects mediated by recombinant GDF11 protein actually reproduce the endogenous functions of MSTN. To clarify the endogenous functions of GDF11, here, we focus on genetic studies and show thatGdf11null mice, despite significantly down-regulatingMstnexpression, exhibit reduced bone mass through impaired osteoblast (OB) and chondrocyte (CH) maturations and increased osteoclastogenesis, while the opposite is observed inMstnnull mice that display enhanced bone mass. Mechanistically,Mstndeletion up-regulatesGdf11expression, which activates bone morphogenetic protein (BMP) signaling pathway to enhance osteogenesis. Also, mice overexpressing follistatin (FST), a MSTN/GDF11 inhibitor, exhibit increased muscle mass accompanied by bone fractures, unlikeMstnnull mice that display increased muscle mass without fractures, indicating that inhibition of GDF11 impairs bone strength. Together, our findings suggest that GDF11 promotes osteogenesis in contrast to MSTN, and these opposing roles of GDF11 and MSTN must be considered to avoid the detrimental effect of GDF11 inhibition when developing MSTN/GDF11 inhibitors for therapeutic purposes.

scholarly journals The Anti-Cancer Effects of a Zotarolimus and 5-Fluorouracil Combination Treatment on A549 Cell-Derived Tumors in BALB/c Nude Mice

2021 ◽  
Vol 22 (9) ◽  
pp. 4562
Author(s):  
Ching-Feng Wu ◽  
Ching-Yang Wu ◽  
Robin Y.-Y. Chiou ◽  
Wei-Cheng Yang ◽  
Chuen-Fu Lin ◽  
...  
Keyword(s):  
Growth Factor ◽  
Tumor Growth ◽  
Lung Adenocarcinoma ◽  
Nude Mice ◽  
Transforming Growth Factor ◽  
Human Lung ◽  
Transforming Growth Factor Β ◽  
Related Factors ◽  
Human Lung Adenocarcinoma

Zotarolimus is a semi-synthetic derivative of rapamycin and a novel immunosuppressive agent used to prevent graft rejection. The pharmacological pathway of zotarolimus restricts the kinase activity of the mammalian target of rapamycin (mTOR), which potentially leads to reductions in cell division, cell growth, cell proliferation, and inflammation. These pathways have a critical influence on tumorigenesis. This study aims to examine the anti-tumor effect of zotarolimus or zotarolimus combined with 5-fluorouracil (5-FU) on A549 human lung adenocarcinoma cell line implanted in BALB/c nude mice by estimating tumor growth, apoptosis expression, inflammation, and metastasis. We established A549 xenografts in nude mice, following which we randomly divided the mice into four groups: control, 5-FU (100 mg/kg/week), zotarolimus (2 mg/kg/day), and zotarolimus combined with 5-FU. Compared the results with those for control mice, we found that mice treated with zotarolimus or zotarolimus combined with 5-FU retarded tumor growth; increased tumor apoptosis through the enhanced expression of cleaved caspase 3 and extracellular signal-regulated kinase (ERK) phosphorylation; decreased inflammation cytokines levels (e.g., IL-1β, TNF-α, and IL-6); reduced inflammation-related factors such as cyclooxygenase-2 (COX-2) protein and nuclear factor-κB (NF-κB) mRNA; enhanced anti-inflammation-related factors including IL-10 and inhibitor of NF-κB kinase α (IκBα) mRNA; and inhibited metastasis-related factors such as transforming growth factor β (TGF-β), CD44, epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF). Notably, mice treated with zotarolimus combined with 5-FU had significantly retarded tumor growth, reduced tumor size, and increased tumor inhibition compared with the groups of mice treated with 5-FU or zotarolimus alone. The in vivo study confirmed that zotarolimus or zotarolimus combined with 5-FU could retard lung adenocarcinoma growth and inhibit tumorigenesis. Zotarolimus and 5-FU were found to have an obvious synergistic tumor-inhibiting effect on lung adenocarcinoma. Therefore, both zotarolimus alone and zotarolimus combined with 5-FU may be potential anti-tumor agents for treatment of human lung adenocarcinoma.

scholarly journals Cell-Intrinsic Transforming Growth Factor-β Signaling Mediates Virus-Specific CD8+ T Cell Deletion and Viral Persistence In Vivo

Immunity ◽  
2009 ◽  
Vol 31 (1) ◽  
pp. 145-157 ◽  
Author(s):  
Roberto Tinoco ◽  
Victor Alcalde ◽  
Yating Yang ◽  
Karsten Sauer ◽  
Elina I. Zuniga
Keyword(s):  
T Cell ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Viral Persistence ◽  
Transforming Growth Factor Β ◽  
Cd8 T Cell ◽  
Cell Deletion
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