Inhibition of EGFR Signaling Protects from Mucormycosis

Mucormycosis is a life-threatening, invasive fungal infection that is caused by various species belonging to the order Mucorales. Rhizopus species are the most common cause of the disease, responsible for approximately 70% of all cases of mucormycosis. During pulmonary mucormycosis, inhaled Rhizopus spores must adhere to and invade airway epithelial cells in order to establish infection. The molecular mechanisms that govern this interaction are poorly understood. We performed an unbiased survey of the host transcriptional response during early stages of Rhizopus arrhizus var. delemar (R. delemar) infection in a murine model of pulmonary mucormycosis using transcriptome sequencing (RNA-seq). Network analysis revealed activation of the host’s epidermal growth factor receptor (EGFR) signaling. Consistent with the RNA-seq results, EGFR became phosphorylated upon in vitro infection of human alveolar epithelial cells with several members of the Mucorales, and this phosphorylated, activated form of EGFR colocalized with R. delemar spores. Inhibition of EGFR signaling with cetuximab or gefitinib, specific FDA-approved inhibitors of EGFR, significantly reduced the ability of R. delemar to invade and damage airway epithelial cells. Furthermore, gefitinib treatment significantly prolonged survival of mice with pulmonary mucormycosis, reduced tissue fungal burden, and attenuated the activation of EGFR in response to pulmonary mucormycosis. These results indicate EGFR represents a novel host target to block invasion of alveolar epithelial cells by R. delemar, and inhibition of EGFR signaling provides a novel approach for treating mucormycosis by repurposing an FDA-approved drug.Mucormycosis is an increasingly common, highly lethal fungal infection with very limited treatment options. Using a combination of in vivo animal models, transcriptomics, cell biology, and pharmacological approaches, we have demonstrated that Mucorales fungi activate EGFR signaling to induce fungal uptake into airway epithelial cells. Inhibition of EGFR signaling with existing FDA-approved drugs significantly increased survival following R. arrhizus var. delemar infection in mice. This study enhances our understanding of how Mucorales fungi invade host cells during the establishment of pulmonary mucormycosis and provides a proof-of-concept for the repurposing of FDA-approved drugs that target EGFR function

Inhibition of EGFR Signaling Protects from Mucormycosis.

Mucormycosis is a life-threatening, invasive fungal infection that is caused by various species belonging to the order Mucorales. Rhizopus species are the most common cause of the disease, responsible for approximately 70% of all cases of mucormycosis. During pulmonary mucormycosis, inhaled Rhizopus spores must adhere to and invade airway epithelial cells in order to establish infection. The molecular mechanisms that govern this interaction are poorly understood. We performed an unbiased survey of the host transcriptional response during early stages of Rhizopus arrhizus var. delemar (R. delemar) infection in a murine model of pulmonary mucormycosis using transcriptome sequencing (RNA-seq). Network analysis revealed activation of the host's epidermal growth factor receptor (EGFR) signaling. Consistent with the RNA-seq results, EGFR became phosphorylated upon in vitro infection of human alveolar epithelial cells with several members of the Mucorales, and this phosphorylated, activated form of EGFR colocalized with R. delemar spores. Inhibition of EGFR signaling with cetuximab or gefitinib, specific FDA-approved inhibitors of EGFR, significantly reduced the ability of R. delemar to invade and damage airway epithelial cells. Furthermore, gefitinib treatment significantly prolonged survival of mice with pulmonary mucormycosis, reduced tissue fungal burden, and attenuated the activation of EGFR in response to pulmonary mucormycosis. These results indicate EGFR represents a novel host target to block invasion of alveolar epithelial cells by R. delemar, and inhibition of EGFR signaling provides a novel approach for treating mucormycosis by repurposing an FDA-approved drug.IMPORTANCE Mucormycosis is an increasingly common, highly lethal fungal infection with very limited treatment options. Using a combination of in vivo animal models, transcriptomics, cell biology, and pharmacological approaches, we have demonstrated that Mucorales fungi activate EGFR signaling to induce fungal uptake into airway epithelial cells. Inhibition of EGFR signaling with existing FDA-approved drugs significantly increased survival following R. arrhizus var. delemar infection in mice. This study enhances our understanding of how Mucorales fungi invade host cells during the establishment of pulmonary mucormycosis and provides a proof-of-concept for the repurposing of FDA-approved drugs that target EGFR function

The Cervicovaginal Microbiota-Host Interaction Modulates Chlamydia trachomatis Infection

The mechanism(s) by which Lactobacillus-dominated cervicovaginal microbiota provide a barrier to Chlamydia trachomatis infection remain(s) unknown. Here we evaluate the impact of different Lactobacillus spp. identified via culture-independent metataxonomic analysis of C. trachomatis-infected women on C. trachomatis infection in a three-dimensional (3D) cervical epithelium model. Lactobacillus spp. that specifically produce d(-) lactic acid were associated with long-term protection against C. trachomatis infection, consistent with reduced protection associated with Lactobacillus iners, which does not produce this isoform, and with decreased epithelial cell proliferation, consistent with the observed prolonged protective effect. Transcriptomic analysis revealed that epigenetic modifications involving histone deacetylase-controlled pathways are integral to the cross talk between host and microbiota. These results highlight a fundamental mechanism whereby the cervicovaginal microbiota modulates host functions to protect against C. trachomatis infection.IMPORTANCE The vaginal microbiota is believed to protect women against Chlamydia trachomatis, the etiologic agent of the most prevalent sexually transmitted infection (STI) in developed countries. The mechanism underlying this protection has remained elusive. Here, we reveal the comprehensive strategy by which the cervicovaginal microbiota modulates host functions to protect against chlamydial infection, thereby providing a novel conceptual mechanistic understanding. Major implications of this work are that (i) the impact of the vaginal microbiota on the epithelium should be considered in future studies of chlamydial infection and other STIs and (ii) a fundamental understanding of the cervicovaginal microbiota's role in protection against STIs may enable the development of novel microbiome-based therapeutic strategies to protect women from infection and improve vaginal and cervical health

The Cervicovaginal Microbiota-Host Interaction Modulates Chlamydia trachomatis Infection

The vaginal microbiota is believed to protect women against Chlamydia trachomatis, the etiologic agent of the most prevalent sexually transmitted infection (STI) in developed countries. The mechanism underlying this protection has remained elusive. Here, we reveal the comprehensive strategy by which the cervicovaginal microbiota modulates host functions to protect against chlamydial infection, thereby providing a novel conceptual mechanistic understanding. Major implications of this work are that (i) the impact of the vaginal microbiota on the epithelium should be considered in future studies of chlamydial infection and other STIs and (ii) a fundamental understanding of the cervicovaginal microbiota’s role in protection against STIs may enable the development of novel microbiome-based therapeutic strategies to protect women from infection and improve vaginal and cervical health.The mechanism(s) by which Lactobacillus-dominated cervicovaginal microbiota provide a barrier to Chlamydia trachomatis infection remain(s) unknown. Here we evaluate the impact of different Lactobacillus spp. identified via culture-independent metataxonomic analysis of C. trachomatis-infected women on C. trachomatis infection in a three-dimensional (3D) cervical epithelium model. Lactobacillus spp. that specifically produce d(−) lactic acid were associated with long-term protection against C. trachomatis infection, consistent with reduced protection associated with Lactobacillus iners, which does not produce this isoform, and with decreased epithelial cell proliferation, consistent with the observed prolonged protective effect. Transcriptomic analysis revealed that epigenetic modifications involving histone deacetylase-controlled pathways are integral to the cross talk between host and microbiota. These results highlight a fundamental mechanism whereby the cervicovaginal microbiota modulates host functions to protect against C. trachomatis infection

Additional file 2 of Lactic acid from vaginal microbiota enhances cervicovaginal epithelial barrier integrity by promoting tight junction protein expression

Additional file 2: Supplementary Table 1. Proteins with significantly different abundance in women with high as compared to low L-LDH and D-LDH abundance*. Supplementary Table 2. Barrier-related proteins with significantly different abundance in women with high as compared to low L-LDH abundance*. Supplementary Table 3. Genes differentially expressed by L-LA, D-LA and HCL treatment of Ect cells*. Supplementary Table 4. Gene ontology pathways significantly enriched by L-LA and D-LA treatment of Ect cells. Supplementary Table 5. Tight junction genes differentially expressed by L-LA, D-LA and HCL treatment of Ect cells*. Supplementary Table 6. Tight junction genes differentially expressed by treatment of VK2 cells with bacterial culture supernatants*