Smad7 plays a protective role in Ang II-induced cardiac remodelling via mechanisms involving the Sp1-TGF-β/Smad-NF-κB-miR-29 regulatory network. Thus, Smad7 may be a novel therapeutic agent for hypertensive cardiovascular diseases.
Smad7 is an inhibitory Smad and plays a protective role in obstructive and diabetic kidney disease. However, the role and mechanisms of Smad7 in hypertensive nephropathy remains unexplored. Thus, the aim of this study was to investigate the role and regulatory mechanisms of Smad7 in ANG II-induced hypertensive nephropathy. Smad7 gene knockout (KO) and wild-type (WT) mice received a subcutaneous infusion of ANG II or control saline for 4 weeks via osmotic mini-pumps. ANG II infusion produced equivalent hypertension in Smad7 KO and WT mice; however, Smad7 KO mice exhibited more severe renal functional injury as shown by increased proteinuria and reduced renal function (both p<0.05) when compared with Smad7 WT mice. Enhanced renal injury in Smad7 KO mice was associated with more progressive renal fibrosis with elevated TGF-β/Smad3 signalling. Smad7 KO mice also showed more profound renal inflammation including increased macrophage infiltration, enhanced IL-1β and TNF-α expression, and a marked activation of NF-κB signaling (all p<0.01). Further studies revealed that enhanced ANG II-mediated renal inflammation and fibrosis in Smad7 KO mice were also associated with up-regulation of Sp1 but downregulation of miR-29b expression. Taken together, the present study revealed that enhanced Sp1-TGF-β1/Smad3-NF-κB signaling and loss of miR-29 may be mechanisms by which deletion of Smad7 promotes ANG II-mediated renal fibrosis and inflammation. Thus, Smad7 may play a protective role in ANG II-induced hypertensive kidney disease.
Smad7 has been shown to negatively regulate fibrosis and inflammation, but its role in angiotensin II (Ang II)-induced hypertensive cardiac remodeling remains unknown. Therefore, the present study investigated the role of Smad7 in hypertensive cardiopathy induced by angiotensin II infusion. Hypertensive cardiac disease was induced in Smad7 gene knockout (KO) and wild-type (WT) mice by subcutaneous infusion of Ang II (1.46 mg/kg/day) for 28 days. Although equal levels of high blood pressure were developed in both Smad7 KO and WT mice, Smad7 KO mice developed more severe cardiac injury as demonstrated by impairing cardiac function including a significant increase in left ventricular (LV) mass (P<0.01),reduction of LV ejection fraction(P<0.001) and fractional shortening(P<0.001). Real-time PCR, Western blot and immunohistochemistry detected that deletion of Smad7 significantly enhanced Ang II-induced cardiac fibrosis and inflammation, including upregulation of collagen I, α-SMA, interleukin-1β, TNF-α, and infiltration of CD3+ T cells and F4/80+ macrophages. Further studies revealed that enhanced activation of the Sp1-TGFβ/Smad3-NF-κB pathways and downregulation of miR-29 were mechanisms though which deletion of Smad7 promoted Ang II-mediated cardiac remodeling. In conclusions, Smad7 plays a protective role in AngII-mediated cardiac remodeling via mechanisms involving the Sp1-TGF-β/Smad3-NF.κB-miR-29 regulatory network.
The TGFβ (transforming growth factor β)/SMAD and NF-κB (nuclear factor κB) signalling pathways play a key role in hypertensive nephropathy. The present study examined whether targeting these pathways by SMAD7, a downstream inhibitor of both pathways, blocks AngII (angiotensin II)-induced hypertensive kidney disease in mice. A doxycycline-inducible SMAD7-expressing plasmid was delivered into the kidney by a non-invasive ultrasound-microbubble technique before and after AngII infusion. Results showed that pre-treatment with SMAD7 prevented AngII-induced progressive renal injury by inhibiting an increase in proteinuria and serum creatinine while improving the glomerular filtration rate. Similarly, treatment with SMAD7 in the established hypertensive nephropathy at day 14 after AngII infusion halted the progressive renal injury. These preventive and therapeutic effects of SMAD7 on hypertensive kidney injury were associated with inhibition of AngII-induced up-regulation of SMURF2 (SMAD-specific E3 ubiquitin protein ligase 2) and Sp1 (specificity protein 1), blockade of TGFβ/Smad3-mediated renal fibrosis and suppression of NF-κB-driven renal inflammation. Moreover, overexpression of SMAD7 also prevented AngII-induced loss of renal miR-29b, an miRNA with an inhibitory role in both TGFβ/Smad3 and NF-κB pathways. In conclusion, SMAD7 may be a therapeutic agent for AngII-mediated hypertensive nephropathy. Inhibition of the Sp1/SMAD3/NF-κB/miR-29b regulatory network may be a mechanism by which SMAD7 inhibits hypertensive nephropathy.
Whether craniospinal irradiation (CSI) could be replaced by limited-field radiation in nonmetastatic bifocal germinoma remains controversial. We addressed the issue based on the data from our series and the literature. Materials and Methods Data from 49 patients diagnosed with non-metastatic bifocal germinoma at our hospital during the last 10 years were collected. The Pediatric Quality of Life Inventory 4.0 was used to evaluate health-related quality of life (HRQOL). Additionally, 81 patients identified from the literature were also analyzed independently. Results In our cohort, 34 patients had tumors in the sellar/suprasellar (S/SS) plus pineal gland (PG) regions and 15 in the S/SS plus basal ganglia/thalamus (BG/T) regions. The median follow-up period was 52 months (range, 10 to 134 months). Our survival analysis showed that patients treated with CSI (n=12) or whole-brain radiotherapy (WBRT; n=34) had comparable disease-free survival (DFS; p=0.540), but better DFS than those treated with focal radiotherapy (FR; n=3, p=0.016). All 81 patients from the literature had tumors in the S/ SS+PG regions. Relapses were documented in 4/45 patients treated with FR, 2/17 treated with whole-ventricle irradiation, 0/4 treated with WBRT, and 1/15 treated with CSI. Survival analysis did not reveal DFS differences between the types of radiation field (p=0.785). HRQOL analysis (n=44) in our cohort found that, compared with S/SS+PG germinoma, patients with BG/T involvement had significantly lower scores in social and school domains. However, HRQOL difference between patients treated with CSI and those not treated with CSI was not significant. Conclusion In patients with non-metastatic bifocal germinoma, it is rational that CSI could be replaced by limited-field radiation. HRQOL in patients with BG/T involvement was poorer.
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