Inhibition of aquaporin-4 expression in astrocytes by RNAi determines alteration in cell morphology, growth, and water transport and induces changes in ischemia-related genes.
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| Abstract |
Recent studies indicate a key role of aquaporin (AQP) 4 in astrocyte swelling and brain edema and suggest that AQP4 inhibition may be a new therapeutic way for reducing cerebral water accumulation. To understand the physiological role of AQP4-mediated astroglial swelling, we used 21-nucleotide small interfering RNA duplexes (siRNA) to specifically suppress AQP4 expression in astrocyte primary cultures. Semiquantitative RT-PCR experiments and Western blot analysis showed that AQP4 silencing determined a progressive and parallel reduction in AQP4 mRNA and protein. AQP4 gene suppression determined the appearance of a new morphological cell phenotype associated with a strong reduction in cell growth. Water transport measurements showed that the rate of shrinkage of AQP4 knockdown astrocytes was one-half of that of controls. Finally, cDNA microarray analysis revealed that the gene expression pattern perturbed by AQP4 gene silencing concerned ischemia-related genes, such as GLUT1 and hexokinase. Taken together, these results indicate that 1) AQP4 seems to be the major factor responsible for the fast water transport of cultured astrocytes; 2) as in skeletal muscle, AQP4 is a protein involved in cell plasticity; 3) AQP4 alteration may be a primary factor in ischemia-induced cerebral edema; and 4) RNA interference could be a new potent tool for studying AQP pathophysiology in those organs and tissues where they are expressed.
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| Authors | Grazia Paola Nicchia, Antonio Frigeri, Grazia Maria Liuzzi, Maria Svelto |
| Journal | FASEB journal : official publication of the Federation of American Societies for Experimental Biology (FASEB J) Vol. 17 Issue 11 Pg. 1508-10 (Aug 2003) ISSN: 1530-6860 [Electronic] United States |
| PMID | 12824287 (Publication Type: Journal Article) |
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