VEGF-A Stimulates STAT3 Activity via Nitrosylation of Myocardin to Regulate the Expression of Vascular Smooth Muscle Cell Differentiation Markers.

Vascular endothelial growth factor A (VEGF-A) is a pivotal player in angiogenesis. It is capable of influencing such cellular processes as tubulogenesis and vascular smooth muscle cell (VSMC) proliferation, yet very little is known about the actual signaling events that mediate VEGF-A induced VSMC phenotypic switch. In this report, we describe the identification of an intricate VEGF-A-induced signaling cascade that involves VEGFR2, STAT3, and Myocardin. We demonstrate that VEGF-A promotes VSMC proliferation via VEGFR2/STAT3-mediated upregulating the proliferation of markers like Cyclin D1 and PCNA. Specifically, VEGF-A leads to nitrosylation of Myocardin, weakens its effect on promoting the expression of contractile markers and is unable to inhibit the activation of STAT3. These observations reinforce the importance of nitric oxide and S-nitrosylation in angiogenesis and provide a mechanistic pathway for VEGF-A-induced VSMC phenotypic switch. In addition, Myocardin, GSNOR and GSNO can create a negative feedback loop to regulate the VSMC phenotypic switch. Thus, the discovery of this interactive network of signaling pathways provides novel and unexpected therapeutic targets for angiogenesis-dependent diseases.

[Effect of combined therapy with Chinese drug and narrow broad ultraviolet B on Bcl-2, caspase-3 and survivin in skin lesion with psoriasis vulgaris].

OBJECTIVE: To reveal the possible role of combined therapy with Chinese drug and narrow broad ultraviolet B (NB-UVB) on keratinocytes apoptosis in skin lesion of psoriasis vulgaris (PV). METHODS: Skin samples were taken from 20 healthy subjects and 30 PV patients before and after they received the combined therapy for 8 weeks. SP immunohistochemical method was used to detect the expressions of Bcl-2, Caspase-3 and survivin in the samples. RESULTS: As compared with those in the normal skin, expression of Bcl-2 in PV skin was significantly lower (7.50 +/- 2.01 vs. 12.65 +/- 2.83), while expression of Caspase-3 (21.73 +/- 3.70 vs. 8.55 +/- 2.16), and survivin (23.90 +/- 2.82 vs. 7.06 +/- 1.96) were higher (all P < 0.01). After treatment, in skin of PV, Bcl-2 expression increased to 13.63 +/- 2.14, Caspase-3 and survivin decreased to 11.70 +/- 2.44 and 12.46 +/- 1.80, respectively (all P < 0.01), showing a normalizing trend. Moreover, patients' psoriasis area and severity index (PASI) score decreased from 14.24 +/- 3.42 before treatment to 3.52 +/- 1.07 after treatment (P < 0.01). CONCLUSION: The curing effect of the combined therapy with Chinese drug and NB-UVB in treating PV is possibly realized by way of regulating Bcl-2, Caspase-3 and survivin expressions to adjust keratinocyte apoptosis.