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Lyu S, Zhang T, Peng P, Cao D, Ma L, Yu Y, Dong Y, Qi X, Wei C. Involvement of cGAS/STING Signaling in the Pathogenesis of Candida albicans Keratitis: Insights From Genetic and Pharmacological Approaches. Invest Ophthalmol Vis Sci 2024; 65:13. [PMID: 38848078 PMCID: PMC11166223 DOI: 10.1167/iovs.65.6.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 05/14/2024] [Indexed: 06/13/2024] Open
Abstract
Purpose Fungal keratitis (FK) is an invasive corneal infection associated with significant risk to vision. Although the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) signaling pathway has been recognized for its role in defending against viral infections, its involvement in FK still remains largely unclear. This study sought to elucidate the contribution of the cGAS/STING signaling pathway to the pathogenesis of FK. Methods The expression of cGAS/STING signaling components was assessed in a murine model of Candida albicans keratitis through RNA sequencing, western blot analysis, immunofluorescence staining, and real-time PCR. Both genetic (utilizing Sting1gt/gt mice) and pharmacological (using C176) interventions were employed to inhibit STING activity, allowing for the evaluation of resultant pathogenic alterations in FK using slit-lamp examination, clinical scoring, hematoxylin and eosin (H&E) staining, fungal culture, and RNA sequencing. Subconjunctival administration of the NOD-like receptor protein 3 (NLRP3) inflammasome inhibitor MCC950 was performed to evaluate FK manifestations following STING activity blockade. Furthermore, the impact of the STING agonist diABZI on FK progression was investigated. Results Compared to uninfected corneas, those infected with C. albicans exhibited increased expression of cGAS/STING signaling components, as well as its elevated activity. Inhibiting cGAS/STING signaling exacerbated the advancement of FK, as evidenced by elevated clinical scores, augmented fungal load, and heightened inflammatory response, including NLRP3 inflammasome activation and pyroptosis. Pharmacological inhibition of the NLRP3 inflammasome effectively mitigated the exacerbated FK by suppressing STING activity. Conversely, pre-activation of STING exacerbated FK progression compared to the PBS control, characterized by increased fungal burden and reinforced inflammatory infiltration. Conclusions This study demonstrates the essential role of the cGAS/STING signaling pathway in FK pathogenesis and highlights the necessity of its proper activation for the host against FK.
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Affiliation(s)
- Shanmei Lyu
- Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Ting Zhang
- Eye Hospital of Shandong First Medical University, Eye Institute of Shandong First Medical University, Jinan, Shandong, China
| | - Peng Peng
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Dingwen Cao
- Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Li Ma
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Yang Yu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Yanling Dong
- Qingdao Eye Hospital of Shandong First Medical University, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Xiaolin Qi
- Eye Hospital of Shandong First Medical University, Eye Institute of Shandong First Medical University, Jinan, Shandong, China
- School of Ophthalmology, Shandong First Medical University, Jinan, Shandong, China
| | - Chao Wei
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
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Jayaprakash AD, Ronk AJ, Prasad AN, Covington MF, Stein KR, Schwarz TM, Hekmaty S, Fenton KA, Geisbert TW, Basler CF, Bukreyev A, Sachidanandam R. Marburg and Ebola Virus Infections Elicit a Complex, Muted Inflammatory State in Bats. Viruses 2023; 15:350. [PMID: 36851566 PMCID: PMC9958679 DOI: 10.3390/v15020350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 01/28/2023] Open
Abstract
The Marburg and Ebola filoviruses cause a severe, often fatal, disease in humans and nonhuman primates but have only subclinical effects in bats, including Egyptian rousettes, which are a natural reservoir of Marburg virus. A fundamental question is why these viruses are highly pathogenic in humans but fail to cause disease in bats. To address this question, we infected one cohort of Egyptian rousette bats with Marburg virus and another cohort with Ebola virus and harvested multiple tissues for mRNA expression analysis. While virus transcripts were found primarily in the liver, principal component analysis (PCA) revealed coordinated changes across multiple tissues. Gene signatures in kidney and liver pointed at induction of vasodilation, reduction in coagulation, and changes in the regulation of iron metabolism. Signatures of immune response detected in spleen and liver indicated a robust anti-inflammatory state signified by macrophages in the M2 state and an active T cell response. The evolutionary divergence between bats and humans of many responsive genes might provide a framework for understanding the differing outcomes upon infection by filoviruses. In this study, we outline multiple interconnected pathways that respond to infection by MARV and EBOV, providing insights into the complexity of the mechanisms that enable bats to resist the disease caused by filoviral infections. The results have the potential to aid in the development of new strategies to effectively mitigate and treat the disease caused by these viruses in humans.
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Affiliation(s)
| | - Adam J. Ronk
- Department of Pathology, the University Texas Medical Branch, Galveston, TX 77555, USA
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Abhishek N. Prasad
- Department of Pathology, the University Texas Medical Branch, Galveston, TX 77555, USA
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | | | - Kathryn R. Stein
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Toni M. Schwarz
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Saboor Hekmaty
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Karla A. Fenton
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
- Department Microbiology & Immunology, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Thomas W. Geisbert
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
- Department Microbiology & Immunology, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Christopher F. Basler
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Alexander Bukreyev
- Department of Pathology, the University Texas Medical Branch, Galveston, TX 77555, USA
- Galveston National Laboratory, the University of Texas Medical Branch, Galveston, TX 77555, USA
- Department Microbiology & Immunology, the University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Ravi Sachidanandam
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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