A Novel In Vivo Model of Laryngeal Papillomavirus-Associated Disease Using Mus musculus Papillomavirus

Abstract

Recurrent respiratory papillomatosis (RRP), caused by laryngeal infection with low-risk human papillomaviruses, has devastating effects on vocal communication and quality of life. Factors in RRP onset, other than viral presence in the airway, are poorly understood. RRP research has been stalled by limited preclinical models. The only known papillomavirus able to infect laboratory mice, Mus musculus papillomavirus (MmuPV1), induces disease in a variety of tissues. We hypothesized that MmuPV1 could infect the larynx as a foundation for a preclinical model of RRP. We further hypothesized that epithelial injury would enhance the ability of MmuPV1 to cause laryngeal disease, because injury is a potential factor in RRP and promotes MmuPV1 infection in other tissues. In this report, we infected larynges of NOD scid gamma mice with MmuPV1 with and without vocal fold abrasion and measured infection and disease pathogenesis over 12 weeks. Laryngeal disease incidence and severity increased earlier in mice that underwent injury in addition to infection. However, laryngeal disease emerged in all infected mice by week 12, with or without injury. Secondary laryngeal infections and disease arose in nude mice after MmuPV1 skin infections, confirming that experimentally induced injury is dispensable for laryngeal MmuPV1 infection and disease in immunocompromised mice. Unlike RRP, lesions were relatively flat dysplasias and they could progress to cancer. Similar to RRP, MmuPV1 transcript was detected in all laryngeal disease and in clinically normal larynges. MmuPV1 capsid protein was largely absent from the larynx, but productive infection arose in a case of squamous metaplasia at the level of the cricoid cartilage. Similar to RRP, disease spread beyond the larynx to the trachea and bronchi. This first report of laryngeal MmuPV1 infection provides a foundation for a preclinical model of RRP.

Expanded Basal Compartment and Disrupted Barrier in Vocal Fold Epithelium Infected with Mouse Papillomavirus MmuPV1

“…Carcinoma in situ was graded as severe dysplasia. Detailed methods for animal experiments, MmuPV1 infection, sample collection, and pathology grading can be found in our companion paper [ 3 ].…”

“…40× magnification. Some H&E and RNAscope images reproduced with permission from our companion paper [ 3 ]. ( A ) Trachea.…”

“…Arrows: MmuPV1-positive focal dysplasia with epithelial laminin and reduced E-cadherin and ZO-1. Some H&E and RNAscope images reproduced with permission from our companion paper [ 3 ].…”

“…RRP research has been slowed due to insufficient model systems [ 2 ]. In our companion paper [ 3 ], we described a novel mouse model of laryngeal papillomavirus infection using Mus musculus papillomavirus (MmuPV1). We found that, while vocal fold infections with MmuPV1 could cause benign disease, progression to cancer was frequent in our model, whereas it is rare in human RRP [ 4 ].…”

Molecular Mechanisms of MmuPV1 E6 and E7 and Implications for Human Disease

“…In 2011, a naturally occurring papillomavirus was discovered in a colony of nude mice in India [ 36 ]. This murine papillomavirus, now termed MmuPV1, was fully sequenced and has been used to infect both immunocompetent and immunocompromised mice [ 172 , 173 , 174 , 175 , 176 , 177 , 178 , 179 ]. Experiments can be done by infecting scarified skin with in vitro generated quasiviruses, by applying recircularized DNA genomes MmuPV1 or by using virus generated from infected mice to experimentally infect tissues.…”