Lentivirus‐ and shRNA‐based smooth muscle‐specific TRPC3 channel knockdown as an emerging therapeutic for asthma

Abstract

A major pathological feature of asthma is airway smooth muscle (ASM) hyperresponsiveness, which is the rationale for using bronchodilators as the first‐line therapy for asthma. The molecular mechanisms for airway hyperresponsiveness remain incompletely understood. The transcription factor nuclear factor‐κB (NFκB) is increasing known to be important for asthma. Using the TFSEARCH program, we have found that NFκB has specific binding sites on the promoter region of canonical transient receptor potential‐3 (TRPC3) channel, a crucial player for numerous pathological cellular responses in a variety of cells. Our investigations have revealed that tumor necrosis factor‐α (TNFα), an important asthmatic mediator, could significantly augment the luciferase intensity in mouse ASM cells (ASMCs) transfected with TRPC3 channel promoter/PGL3 luciferase reporter vectors, indicating an increase in the channel promoter activity. The TNFα‐induced increase in TRPC3 channel promoter activity was blocked by specific NFκB inhibition. Similarly, NFκB‐dependent increased TRPC3 channel promoter activity was observed in ASMCs from mice with allergen‐evoked asthma. We have also demonstrated that among all 7 TRPC channel members, only TRPC3 channel showed a predominant functional activity in ASMCs. TRPC3 channel gene and protein expression levels were much higher in asthmatic mouse ASMCs. More importantly, intravenous or intranasal delivery of lentiviruses encoding the SMC promoter SM22α‐driven mouse TRPC3 channel shRNAs in mice caused a sufficient knockdown of the channel expression and function in ASMCs. The TRPC3 channel knockdown mice had no asthmatic airway hyperresponsiveness. Moreover, lentiviral shRNA‐based SMC‐specific TRPC3 channel knockdown blocked ASM remodeling (known as another major asthmatic pathological feature) in asthmatic mice. Taken together, we conclude that TRPC3 channel serves as an essential mediator of the functional role of the transcription factor NF‐κB in asthma; as such, NF‐κB underlies the asthmatic increase in TRPC3 channel promoter activity, expression and function in ASMCs, leading to airway hyperresponsiveness and remodeling. Evidently, lentivirus‐ and shRNA‐based SMC‐specific TRPC3 channel knockdown is an emerging therapeutic for asthma.Support or Funding InformationHL122865This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.