11 research outputs found
Disruption of Smad7 Promotes ANG II-Mediated Renal Inflammation and Fibrosis via Sp1-TGF-β/Smad3-NF.κB-Dependent Mechanisms in Mice
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. © 2013 Liu et al.published_or_final_versio
Deficiency of Smad7 Enhances Cardiac Remodeling Induced by Angiotensin II Infusion in a Mouse Model of Hypertension
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. © 2013 Wei et al.published_or_final_versio
Stroma-regulated HMGA2 is an independent prognostic marker in PDAC and AAC
Background: The HMGA2 protein has experimentally been linked to EMT and cancer stemness. Recent studies imply that tumour-stroma interactions regulate these features and thereby contribute to tumour aggressiveness. Methods: We analysed 253 cases of pancreatic ductal adenocarcinoma (PDAC) and 155 cases of ampullary adenocarcinoma (AAC) for HMGA2 expression by IHC. The data were correlated with stroma abundance and supplemented by experimental studies. Results: HMGA2 acts as an independent prognostic marker associated with a significantly shorter overall survival in both tumour types. Overall, HMGA2-positivity was more frequent in patients with PDAC than with AAC. The HMGA2 status in tumour cells significantly correlated with the abundance of PDGFRβ-defined stroma cells. In vivo co-injection of Panc-1 cancer cells with pancreatic stellate cells increased tumour growth in a manner associated with increased HMGA2 expression. Furthermore, in vitro treatment of Panc-1 with conditioned media from PDGF-BB-activated stellate cells increased their ability to form tumour spheroids. Conclusions: This study identifies HMGA2 expression in tumour cells as an independent prognostic marker in PDAC and AAC. Correlative data analysis gives novel tissue-based evidence for a heterotypic cross-talk with stroma cells as a possible mechanism for HMGA2 induction, which is further supported by experimental models
Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma
<p>Abstract</p> <p>Background</p> <p>Platelet-derived growth factor (PDGF)-BB and PDGF receptor (PDGFR)-β are mainly expressed in the developing vasculature, where PDGF-BB is produced by endothelial cells and PDGFR-β is expressed by mural cells, including pericytes. PDGF-BB is produced by most types of solid tumors, and PDGF receptor signaling participates in various processes, including autocrine stimulation of tumor cell growth, recruitment of tumor stroma fibroblasts, and stimulation of tumor angiogenesis. Furthermore, PDGF-BB-producing tumors are characterized by increased pericyte abundance and accelerated tumor growth. Thus, there is a growing interest in the development of tumor treatment strategies by blocking PDGF/PDGFR function. We have recently generated a mouse model carrying an activated PDGFR-β by replacing the highly conserved aspartic acid residue (D) 849 in the activating loop with asparagine (N). This allowed us to investigate, in an orthotopic tumor model, the role of increased stromal PDGFR-β signaling in tumor-stroma interactions.</p> <p>Methods</p> <p>B16 melanoma cells lacking PDGFR-β expression and either mock-transfected or engineered to express PDGF-BB, were injected alone or in combination with matrigel into mice carrying the activated PDGFR-β (D849N) and into wild type mice. The tumor growth rate was followed and the vessel status of tumors, i.e. total vessel area/tumor, average vessel surface and pericyte density of vessels, was analyzed after resection.</p> <p>Results</p> <p>Tumors grown in mice carrying an activated PDGFR-β were established earlier than those in wild-type mice. In this early phase, the total vessel area and the average vessel surface were higher in tumors grown in mice carrying the activated PDGFR-β (D849N) compared to wild-type mice, whereas we did not find a significant difference in the number of tumor vessels and the pericyte abundance around tumor vessels between wild type and mutant mice. At later phases of tumor progression, no significant difference in tumor growth rate was observed between wild type mice and mutant mice, although the pericyte coverage was higher around tumor vessels from mutant mice.</p> <p>Conclusion</p> <p>Our findings suggest that the activated PDGFR-β (D849N) in the host animal increased the total vessel area and the average vessel surface even in PDGF-negative tumors, resulting in a shorter lag phase during tumor establishment.</p
Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma
Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma-3
<p><b>Copyright information:</b></p><p>Taken from "Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma"</p><p>http://www.biomedcentral.com/1471-2407/7/224</p><p>BMC Cancer 2007;7():224-224.</p><p>Published online 12 Dec 2007</p><p>PMCID:PMC2234427.</p><p></p>bed in the legend of figure 2. Tissue sections were analyzed for the ratio of total vessel area/tumor (A), average vessel surface (B), number of vessels per high-power field (C) and numerical density of pericytes per perimeter of vessel (D). Asterisks indicate statistical significance (*, p < 0.01) by Student's -test. Double immunohistochemical staining for vessels (CD31, blue) and perivascular cells (alpha-smooth muscle actin, brown) identify significantly larger vessels in B16 melanoma/matrigel plugs grown in wild type mice (E) compared to D849N-mutant mice (F) (the same magnification was used in Fig. 4E and Fig. 4F)
Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma-5
<p><b>Copyright information:</b></p><p>Taken from "Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma"</p><p>http://www.biomedcentral.com/1471-2407/7/224</p><p>BMC Cancer 2007;7():224-224.</p><p>Published online 12 Dec 2007</p><p>PMCID:PMC2234427.</p><p></p>e subcutaneously injected on both sides of the midline of the lower dorsal abdomen of wild type (wt) or D849N-mutant mice (mut). Six tumors were analyzed for each experimental combination. When the B16 melanomas had reached 0.8 cm, they were removed and analyzed for ratio of total vessel area/viable tumor (A), average vessel surface (B), number of vessels per high-power field (C) and numerical density of pericytes per perimeter of vessel (D). Asterisks indicate statistical significance (*, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001) by Student's -test
Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma-2
<p><b>Copyright information:</b></p><p>Taken from "Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma"</p><p>http://www.biomedcentral.com/1471-2407/7/224</p><p>BMC Cancer 2007;7():224-224.</p><p>Published online 12 Dec 2007</p><p>PMCID:PMC2234427.</p><p></p> Asterisk indicates statistical significance (*, p < 0.05) by Student's -test
Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma-6
<p><b>Copyright information:</b></p><p>Taken from "Platelet-derived growth factor receptor-β, carrying the activating mutation D849N, accelerates the establishment of B16 melanoma"</p><p>http://www.biomedcentral.com/1471-2407/7/224</p><p>BMC Cancer 2007;7():224-224.</p><p>Published online 12 Dec 2007</p><p>PMCID:PMC2234427.</p><p></p>gure 1. Double immunohistochemical staining for endothelial cells (CD31, blue) and perivascular cells (α-smooth muscle actin, brown) in B16 melanoma is shown. Please note the small vessels (blue) covered by few pericyte (brown) in tumors grown in wild type mice (A) compared to larger vessels surrounded by multiple perivascular cells (brown) in tumors grown in D849N-mutant mice (B). Tissue sections were analyzed for total vessel area (C), average vessel surface (D), number of vessels per high-power field (E) and numerical density of pericytes per vessel perimeter (F). Asterisk indicates statistical significance (*, p < 0.01) by Student's -test