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Smad7 functions as an intracellular antagonist in transforming growth factor-beta (TGF-beta) signaling. In addition to interacting stably with the activated TGF-beta type I receptor (TbetaRI) to prevent phosphorylation of the receptor-regulated Smads (Smad2 and Smad3), Smad7 also induces degradation of the activated TbetaRI through association with different E3 ubiquitin ligases. Using the two-hybrid screen, we identified atrophin 1-interacting protein 4 (AIP4) as an E3 ubiquitin ligase that specifically targets Smad7 for ubiquitin-dependent degradation without affecting the turnover of the activated TbetaRI. Surprisingly, we found that despite the ability to degrade Smad7, AIP4 can inhibit TGF-beta signaling, presumably by enhancing the association of Smad7 with the activated TbetaRI. Consistent with this notion, expression of a catalytic mutant of AIP4, which is unable to induce ubiquitination and degradation of Smad7, also stabilizes the TbetaRI.Smad7 complex, resulting in inhibition of TGF-beta signaling. The ability of AIP4 to enhance the inhibitory function of Smad7 independent of its ubiquitin ligase activity reveals a new mechanism by which E3 ubiquitin ligases may function to turn off TGF-beta signaling.
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http://dx.doi.org/10.1074/jbc.M500188200 | DOI Listing |
Adv Mater
September 2025
State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
Bone defect therapy frequently encounters bacterial infections and chronic inflammation, which impair bone regeneration and threaten implant stability. Iron oxide nanoparticles have attracted attention due to cost-effectiveness, biocompatibility, and metabolic safety. However, iron oxide nanoparticles still struggle to balance low-temperature efficient antibacterial activity, effective immunomodulation, and bone regeneration.
View Article and Find Full Text PDFACS Nano
September 2025
Department of Emergency and Critical Care Medicine, The Fourth Affiliated Hospital of Soochow University, Suzhou 215124, China.
Acute lung injury (ALI) is characterized by the excessive accumulation of reactive oxygen species (ROS), which triggers a severe inflammatory cascade and the destruction of the alveolar-capillary barrier, leading to respiratory failure and life-threatening outcomes. Considering the limitations and adverse effects associated with current therapeutic interventions, developing effective and safe strategies that target the complex pathophysiological mechanisms of ALI is crucial for improving patient outcomes. Herein, we developed an inhalable, multifunctional nanotherapeutic (MSCNVs@CAT) by encapsulating catalase (CAT) in mesenchymal-stem-cell-derived nanovesicles (MSCNVs).
View Article and Find Full Text PDFJ Cardiovasc Pharmacol
September 2025
Graduate School of Cardiology, Bengbu Medical University, Bengbu 233000, Anhui, China.
Chronic stress-induced cardiac hypertrophy remains a critical precursor to heart failure, with current therapies limited by incomplete mechanistic targeting. Cyclin-dependent kinases (CDKs), pivotal regulators of cell cycle and stress signaling, are emerging therapeutic targets in cardiovascular pathologies. Using bioinformatics analysis of human hypertrophic cardiomyopathy datasets (GSE5500, GSE136308) and a murine transverse aortic constriction (TAC) model, we investigated the therapeutic effects of the CDK inhibitor R547 (10 mg/kg, intraperitoneal every 3 days) on pressure overload-induced cardiac remodeling.
View Article and Find Full Text PDFFASEB J
September 2025
National Heart Center Singapore, Singapore, Singapore.
Cardiovascular diseases are increasingly recognized as chronic disorders driven by a complex interplay between inflammation and fibrosis. In this review, we elucidate emerging mechanisms that govern the transition from acute inflammation to pathological fibrosis, with particular focus on cellular crosstalk between neutrophils, macrophages, fibroblasts, and myofibroblasts. We explore how dysregulated immune responses and extracellular matrix (ECM) remodeling sustain a pathogenic feedback loop, promoting myocardial stiffening and adverse cardiac remodeling.
View Article and Find Full Text PDFPulm Circ
July 2025
Division of Pulmonary, Critical Care, and Sleep Medicine Tufts Medical Center Boston Massachusetts USA.
Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction, proliferation, fibrosis, and microthrombosis of the pulmonary vasculature, which causes elevated pulmonary arterial pressure and vascular resistance leading to right ventricular failure and death. Previous treatments targeted three known pathways involved in the development of PAH: endothelin, nitric oxide, and prostacyclin. Dysfunctional signaling of the transforming growth factor-beta (TGF-β) family, via bone morphogenetic protein (BMP) receptor 2 and activin signaling, has also been implicated in PAH leading to the development of a new class of therapies.
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