Vascular smooth muscle cells express a constitutive NF-kappa B-like activity

• Published in: The Journal of biological chemistry Vol. 269; no. 46; pp. 28913 - 28918
• Main Authors: Lawrence, R, Chang, L J, Siebenlist, U, Bressler, P, Sonenshein, G E
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 18.11.1994; American Society for Biochemistry and Molecular Biology
• Subjects: AIDS/HIV; Animals; Base Sequence; Cattle; Cells, Cultured; Female; HIV Long Terminal Repeat - genetics; Molecular Sequence Data; Muscle, Smooth, Vascular - metabolism; NF-kappa B - metabolism; Nuclear Proteins - metabolism; Oligodeoxyribonucleotides; Protein Binding; Proto-Oncogene Proteins - physiology; Proto-Oncogene Proteins c-rel; Transcriptional Activation
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)61994-0

The NF-kappa B/Rel family of transcription factors is commonly expressed in non-hematopoietic cells in an inactive form within the cytoplasm, complexed with an inhibitor I kappa B protein. Thus, it was surprising that NF-kappa B element-driven heterologous promoter-reporter gene constructs were active upon transient transfection into vascular smooth muscle cells (VSMCs). Here, we report that VSMCs express a constitutive nuclear NF-kappa B-like activity. In electrophoretic mobility shift assays, nuclear extracts demonstrated binding to a wild type NF-kappa B element but not to those mutated at nucleotides critical for Rel-protein DNA interaction. Binding was abrogated by the presence of I kappa B-alpha. Furthermore, addition of an antibody to the p50 subunit of classical NF-kappa B (but not p65, c-Rel, or RelB) resulted in supershifted complexes. Transactivation of element-driven constructs was negatively affected by co-transfection of a vector expressing a dominant negative p50 subunit, which can dimerize with other Rel subunits but not bind DNA. The long terminal repeat of the human immunodeficiency virus-1, which is driven in part by two NF-kappa B elements, displayed strong activity within VSMCs. This activity was abrogated upon co-transfection of the vector expressing the dominant negative p50 mutant. Taken together, these experiments indicate that VSMCs constitutively express a functional NF-kappa B-like trans-acting factor, which may play a significant role in the regulation of proliferation and viral infection of these cells.