miR144 Regulates Nrf2 Expression In Primary Alveolar Epithelial Cells Derived From HIV‐1 Transgenic Rats
Authors: Fan Xian , Staitieh Bashar B. , Raynor Robert , Kukoyi Abiodun , Guidot David M. 
Published: June 2021

Background

Despite anti‐retroviral therapy, individuals living with human immunodeficiency virus (HIV) type 1 infection have impaired anti‐oxidant defenses within their airways and remain at high risk for lung injury. Recently we reported that chronic expression of HIV‐related proteins in HIV‐1 transgenic (HIV‐1 Tg) rats (which models the chronic expression of these proteins in humans living with HIV) inhibits the expression of Nrf2, the master transcription factor that activates anti‐oxidant defenses, in the alveolar epithelial cells and impairs their barrier function thereby leaving the alveolar epithelium vulnerable to injury. However, the mechanism(s) by which HIV‐related proteins inhibit Nrf2 expression have not been identified. MicroRNAs (miRNAs) are post‐transcriptional regulators that have been shown to play critical roles in mediating the redox balance; in particular, miR144 is known to inhibit Nrf2 but a potential role for miR144 in the context of HIV has not been investigated.

Methods

Primary rat alveolar epithelial cells (AECs) were isolated from HIV‐1 Tg rats and wild type (WT) littermates. Total RNA and miRNA were isolated; real‐time RT‐ PCR and western immunoblots were performed to quantify gene and protein expression of Nrf2 and its downstream effectors, as well as key tight junction proteins involved in epithelial barrier function. miRNAs were quantified by qRT‐PCR. In parallel, miR144 expression was increased by treatment with a miR144 mimic or decreased by treatment with a selective miR144 inhibitor (‘antagomir’) to assess the effects of direct manipulation of miR144 expression on Nrf2.

Results

We first determined that miR144 expression was significantly increased in primary AECs derived from HIV‐1 Tg rats. Further, treating AECs from wild type rats with the miR144 mimic significantly decreased the expression of Nrf2 and its downstream effectors, NAD(P)H dehydrogenase (quinone) 1 (NQO1) and glutamate‐cysteine ligase catalytic subunit (GCLC) and, in parallel, inhibited the expression of the tight junction protein ZO‐1, which is required for alveolar epithelial barrier function. In contrast, treating AECs derived from HIV‐1 Tg rats with the miR144 antagomir significantly increased the expression of Nrf2 and its downstream effectors.

Conclusions

HIV‐1 transgene expression increases miR144 expression in the alveolar epithelium, and overexpression of miR144 directly inhibits Nrf2 expression and signaling as well as the expression of tight junction proteins. In contrast, inhibiting miR144 mitigates these pathophysiological effects of HIV‐related proteins on the alveolar epithelium, suggesting that miR144 could be a novel therapeutic target to enhance lung health in individuals living with HIV.

Support or Funding Information

This study is supported by R01 HL 125042.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.