Date Published:
2019 03 08
Publication Type:
Journal Article
Authors:
Secondary:
J Biol Chem
Volume:
294
Pagination:
3618-3633
Issue:
10
PMID:
30591585
URL:
https://pubmed.ncbi.nlm.nih.gov/30591585
Keywords:
Animals;Brain-derived neurotrophic factor;Cell Line, Tumor;Cyclic AMP Response Element-Binding Protein;E2F3 Transcription Factor;Gene Expression Regulation;Humans;Long-Term Potentiation;Mice;MicroRNAs;Neurites;Neurons;Promoter Regions, Genetic;Synaptophysin;tat Gene Products, Human Immunodeficiency Virus
Abstract:
<p>Individuals who are infected with HIV-1 accumulate damage to cells and tissues ( neurons) that are not directly infected by the virus. These include changes known as HIV-associated neurodegenerative disorder (HAND), leading to the loss of neuronal functions, including synaptic long-term potentiation (LTP). Several mechanisms have been proposed for HAND, including direct effects of viral proteins such as the Tat protein. Searching for the mechanisms involved, we found here that HIV-1 Tat inhibits E2F transcription factor 3 (E2F3), CAMP-responsive element-binding protein (CREB), and brain-derived neurotropic factor (BDNF) by up-regulating the microRNA miR-34a. These changes rendered murine neurons dysfunctional by promoting neurite retraction, and we also demonstrate that E2F3 is a specific target of miR-34a. Interestingly, bioinformatics analysis revealed the presence of an E2F3-binding site within the promoter, which we validated with ChIP and transient transfection assays. Of note, luciferase reporter assays revealed that E2F3 up-regulates expression and that Tat interferes with this up-regulation. Further, we show that miR-34a inhibition or E2F3 overexpression neutralizes Tat's effects and restores normal distribution of the synaptic protein synaptophysin, confirming that Tat alters these factors, leading to neurite retraction inhibition. Our results suggest that E2F3 is a key player in neuronal functions and may represent a good target for preventing the development of HAND.</p>