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Hou X, Li C, Liu J, Yang S, Peng X, Wang Q, Liu C, Liu X, Luan J, Zhao G, Lin J. Cathelicidin boosts the antifungal activity of neutrophils and improves prognosis during Aspergillus fumigatus keratitis. Infect Immun 2024; 92:e0048323. [PMID: 38501672 PMCID: PMC11003229 DOI: 10.1128/iai.00483-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 03/02/2024] [Indexed: 03/20/2024] Open
Abstract
Aspergillus fumigatus (A. fumigatus) is one of the common pathogens of fungal keratitis. Fungal growth and invasion cause excessive inflammation and corneal damage, leading to severe vision loss. Neutrophils are the primary infiltrating cells critical for fungal clearance. Cathelicidin [LL-37 in humans and cathelicidin-related antimicrobial peptide (CRAMP) in mice], a natural antimicrobial peptide, can directly inhibit the growth of many pathogens and regulate immune responses. However, the role of cathelicidin and its effect on neutrophils in A. fumigatus keratitis remain unclear. By establishing A. fumigatus keratitis mouse models, we found that cathelicidin was increased in A. fumigatus keratitis. It could reduce fungal loads, lower clinical scores, and improve corneal transparency. Restriction of CRAMP on fungal proliferation was largely counteracted in CD18-/- mice, in which neutrophils cannot migrate into infected sites. When WT neutrophils were transferred into CD18-/- mice, corneal fungal loads were distinctly reduced, indicating that neutrophils are vital for CRAMP-mediated resistance. Furthermore, cathelicidin promoted neutrophils to phagocytose and degrade conidia both in vitro and in vivo. CXC chemokine receptor 2 (CXCR2) was reported to be a functional receptor of LL-37 on neutrophils. CXCR2 antagonist SB225002 or phospholipase C (PLC) inhibitor U73122 weakened LL-37-induced phagocytosis. Meanwhile, LL-37 induced PLC γ phosphorylation, which was attenuated by SB225002. SB225002 or the autophagy inhibitors Bafilomycin-A1 and 3-Methyladenine weakened LL-37-induced degradation of conidia. Transmission electron microscopy (TEM) observed that LL-37 increased autophagosomes in Aspergillus-infected neutrophils. Consistently, LL-37 elevated autophagy-associated protein expressions (Beclin-1 and LC3-II), but this effect was weakened by SB225002. Collectively, cathelicidin reduces fungal loads and improves the prognosis of A. fumigatus keratitis. Both in vitro and in vivo, cathelicidin promotes neutrophils to phagocytose and degrade conidia. LL-37/CXCR2 activates PLC γ to amplify neutrophils' phagocytosis and induces autophagy to eliminate intracellular conidia.
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Affiliation(s)
- Xiaochen Hou
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Cui Li
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Jingyi Liu
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Shanshan Yang
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Xudong Peng
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Qian Wang
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Chengxiu Liu
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Xing Liu
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Junjie Luan
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Guiqiu Zhao
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Jing Lin
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
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2
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Scarpellini C, Ramos Llorca A, Lanthier C, Klejborowska G, Augustyns K. The Potential Role of Regulated Cell Death in Dry Eye Diseases and Ocular Surface Dysfunction. Int J Mol Sci 2023; 24:731. [PMID: 36614174 PMCID: PMC9820812 DOI: 10.3390/ijms24010731] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/23/2022] [Accepted: 12/29/2022] [Indexed: 01/03/2023] Open
Abstract
The research on new treatments for dry eye diseases (DED) has exponentially grown over the past decades. The increased prevalence of dry eye conditions, particularly in the younger population, has received much attention. Therefore, it is of utmost importance to identify novel therapeutical targets. Regulated cell death (RCD) is an essential process to control the biological homeostasis of tissues and organisms. The identification of different mechanisms of RCD stimulated the research on their involvement in different human pathologies. Whereas apoptosis has been widely studied in DED and included in the DED vicious cycle, the role of RCD still needs to be completely elucidated. In this review, we will explore the potential roles of different types of RCD in DED and ocular surface dysfunction. Starting from the evidence of oxidative stress and inflammation in dry eye pathology, we will analyse the potential therapeutic applications of the following principal RCD mechanisms: ferroptosis, necroptosis, and pyroptosis.
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Affiliation(s)
| | | | | | | | - Koen Augustyns
- Laboratory of Medicinal Chemistry, University of Antwerp, Universiteitsplein 1, B-2160 Antwerp, Belgium
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3
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Mohid SA, Biswas K, Won T, Mallela LS, Gucchait A, Butzke L, Sarkar R, Barkham T, Reif B, Leipold E, Roy S, Misra AK, Lakshminarayanan R, Lee D, Bhunia A. Structural insights into the interaction of antifungal peptides and ergosterol containing fungal membrane. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183996. [PMID: 35753394 DOI: 10.1016/j.bbamem.2022.183996] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
The treatment of invasive drug-resistant and potentially life-threatening fungal infections is limited to few therapeutic options that are usually associated with severe side effects. The development of new effective antimycotics with a more tolerable side effect profile is therefore of utmost clinical importance. Here, we used a combination of complementary in vitro assays and structural analytical methods to analyze the interaction of the de novo antimicrobial peptide VG16KRKP with the sterol moieties of biological cell membranes. We demonstrate that VG16KRKP disturbs the structural integrity of fungal membranes both invitro and in model membrane system containing ergosterol along with phosphatidylethanolamine lipid and exhibits broad-spectrum antifungal activity. As revealed by systematic structure-function analysis of mutated VG16KRKP analogs, a specific pattern of basic and hydrophobic amino acid side chains in the primary peptide sequence determines the selectivity of VG16KRKP for fungal specific membranes.
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Affiliation(s)
- Sk Abdul Mohid
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, EN 80, Sector V, Kolkata 700091, India
| | - Karishma Biswas
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, EN 80, Sector V, Kolkata 700091, India
| | - TaeJun Won
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea
| | - Lakshmi S Mallela
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad 500034, India
| | - Arin Gucchait
- Division of Molecular Medicine, Bose Institute, Unified Academic Campus, Salt Lake, EN 80, Sector V, Kolkata 700091, India
| | - Lena Butzke
- Department of Anesthesiology and Intensive Care & Center of Brain, Behavior and Metabolism, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | | | - Timothy Barkham
- Department of Laboratory Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore
| | - Bernd Reif
- Technical University of Munich, 85748 Garching, Germany
| | - Enrico Leipold
- Department of Anesthesiology and Intensive Care & Center of Brain, Behavior and Metabolism, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Sanhita Roy
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad 500034, India
| | - Anup K Misra
- Division of Molecular Medicine, Bose Institute, Unified Academic Campus, Salt Lake, EN 80, Sector V, Kolkata 700091, India
| | | | - DongKuk Lee
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea.
| | - Anirban Bhunia
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, EN 80, Sector V, Kolkata 700091, India.
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Antimicrobial peptide S100A12 (calgranulin C) inhibits growth, biofilm formation, pyoverdine secretion and suppresses type VI secretion system in Pseudomonas aeruginosa. Microb Pathog 2022; 169:105654. [PMID: 35753599 DOI: 10.1016/j.micpath.2022.105654] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 12/13/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen and is the major cause of corneal infections in India and worldwide. The increase in antimicrobial resistance among Pseudomonas has prompted rise in significant research to develop alternative therapeutics. Antimicrobial peptides (AMPs) are considered as potent alternatives to combat bacterial infections. In this study, we investigated the role of S100A12, a host defense peptide, against PAO1 and an ocular clinical isolate. Increased expression of S100A12 was observed in corneal tissues obtained from Pseudomonas keratitis patients by immunohistochemistry. S100A12 significantly inhibited growth of Pseudomonas in vitro as determined from colony forming units. Furthermore, recombinant S100A12 reduced the corneal opacity and the bacterial load in a mouse model of Pseudomonas keratitis. Transcriptome changes in PAO1 in response to S100A12 was investigated using RNA sequencing. The pathway analysis of transcriptome data revealed that S100A12 inhibits expression of genes involved in pyoverdine synthesis and biofilm formation. It also impedes several important pathways like redox, pyocyanin synthesis and type 6 secretion system (T6SS). The transcriptome data was further validated by checking the expression of several affected genes by quantitative PCR. Our study sheds light on how S100A12 impacts Pseudomonas and that it might have the potential to be used as therapeutic intervention in addition to antibiotics to combat infection in future.
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Shannon AH, Adelman SA, Hisey EA, Potnis SS, Rozo V, Yung MW, Li JY, Murphy CJ, Thomasy SM, Leonard BC. Antimicrobial Peptide Expression at the Ocular Surface and Their Therapeutic Use in the Treatment of Microbial Keratitis. Front Microbiol 2022; 13:857735. [PMID: 35722307 PMCID: PMC9201425 DOI: 10.3389/fmicb.2022.857735] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 05/12/2022] [Indexed: 11/29/2022] Open
Abstract
Microbial keratitis is a common cause of ocular pain and visual impairment worldwide. The ocular surface has a relatively paucicellular microbial community, mostly found in the conjunctiva, while the cornea would be considered relatively sterile. However, in patients with microbial keratitis, the cornea can be infected with multiple pathogens including Staphylococcus aureus, Pseudomonas aeruginosa, and Fusarium sp. Treatment with topical antimicrobials serves as the standard of care for microbial keratitis, however, due to high rates of pathogen resistance to current antimicrobial medications, alternative therapeutic strategies must be developed. Multiple studies have characterized the expression and activity of antimicrobial peptides (AMPs), endogenous peptides with key antimicrobial and wound healing properties, on the ocular surface. Recent studies and clinical trials provide promise for the use of AMPs as therapeutic agents. This article reviews the repertoire of AMPs expressed at the ocular surface, how expression of these AMPs can be modulated, and the potential for harnessing the AMPs as potential therapeutics for patients with microbial keratitis.
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Affiliation(s)
- Allison H. Shannon
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Sara A. Adelman
- William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Erin A. Hisey
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Sanskruti S. Potnis
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Vanessa Rozo
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Madeline W. Yung
- Department of Ophthalmology & Vision Science, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Jennifer Y. Li
- Department of Ophthalmology & Vision Science, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Christopher J. Murphy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Department of Ophthalmology & Vision Science, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Sara M. Thomasy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- Department of Ophthalmology & Vision Science, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Brian C. Leonard
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
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6
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Atomic-Resolution Structures and Mode of Action of Clinically Relevant Antimicrobial Peptides. Int J Mol Sci 2022; 23:ijms23094558. [PMID: 35562950 PMCID: PMC9100274 DOI: 10.3390/ijms23094558] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/18/2022] [Accepted: 04/18/2022] [Indexed: 02/01/2023] Open
Abstract
Global rise of infections and deaths caused by drug-resistant bacterial pathogens are among the unmet medical needs. In an age of drying pipeline of novel antibiotics to treat bacterial infections, antimicrobial peptides (AMPs) are proven to be valid therapeutics modalities. Direct in vivo applications of many AMPs could be challenging; however, works are demonstrating encouraging results for some of them. In this review article, we discussed 3-D structures of potent AMPs e.g., polymyxin, thanatin, MSI, protegrin, OMPTA in complex with bacterial targets and their mode of actions. Studies on human peptide LL37 and de novo-designed peptides are also discussed. We have focused on AMPs which are effective against drug-resistant Gram-negative bacteria. Since treatment options for the infections caused by super bugs of Gram-negative bacteria are now extremely limited. We also summarize some of the pertinent challenges in the field of clinical trials of AMPs.
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7
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Streptococcus pneumoniae exerts oxidative stress, subverts antioxidant signaling and autophagy in human corneal epithelial cells that is alleviated by tert-Butylhydroquinone. Med Microbiol Immunol 2022; 211:119-132. [PMID: 35325292 DOI: 10.1007/s00430-022-00731-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 03/07/2022] [Indexed: 10/18/2022]
Abstract
Streptococcus pneumoniae is one of the leading causes of bacterial keratitis in the developing world and globally. In the current study, we have determined oxidative stress as pathogenesis of S. pneumoniae infection in corneal tissues and human corneal epithelial cells (HCEC) and explored host immune response of HCEC towards S. pneumoniae. We also determined whether treatment with tert-Butylhydroquinone (tBHQ), a Nrf2 inducer, could alleviate oxidative stress and reduce bacterial cytotoxicity in these cells. Oxidative stress was determined in corneal tissues of patients and HCEC by immunohistochemistry and immunofluorescence analysis, respectively. The expression of antioxidant genes, cytokines and antimicrobial peptides was determined by quantitative PCR. Infection of HCEC by S. pneumoniae was determined by colony-forming units. The autophagy and cell death were determined by fluorescence microscopy. The phosphorylation of signaling proteins was evaluated by immunoblot analysis. S. pneumoniae induced oxidative stress during corneal infections and inhibited antioxidant signaling pathways and immune responses like autophagy. tBHQ aided in restoring Nrf2 activation, reduced reactive oxygen species generation and prevented cytotoxicity and cell death in S. pneumoniae-infected HCEC. tBHQ also induced autophagy in a Nrf2-dependent manner and reduced bacterial survival in HCEC. Increased expression of antimicrobial peptides by tBHQ might have contributed to a reduction of bacterial load and cytotoxicity, as exemplified in LL-37 depleted corneal epithelial cells exposed to S. pneumoniae compared to control siRNA-transfected cells. tBHQ mediates alleviation of oxidative stress induced by S. pneumoniae by activating Nrf2-mediated antioxidant signaling in corneal epithelial cells. tBHQ also enhances expression of antimicrobial peptides in corneal cells and aids in inhibition of bacterial survival and cytotoxicity of HCEC.
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8
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Mohid SA, Sharma P, Alghalayini A, Saini T, Datta D, Willcox MD, Ali H, Raha S, Singha A, Lee D, Sahoo N, Cranfield CG, Roy S, Bhunia A. A rationally designed synthetic antimicrobial peptide against Pseudomonas-associated corneal keratitis: Structure-function correlation. Biophys Chem 2022; 286:106802. [DOI: 10.1016/j.bpc.2022.106802] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/10/2022] [Accepted: 03/15/2022] [Indexed: 11/02/2022]
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Mallela LS, Sharma P, Rao TSR, Roy S. Recombinant IL-22 promotes protection in a murine model of Aspergillus flavus keratitis and mediates host immune responses in human corneal epithelial cells. Cell Microbiol 2021; 23:e13367. [PMID: 34029434 DOI: 10.1111/cmi.13367] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 12/23/2022]
Abstract
Aspergillus flavus is a leading cause of corneal infections in India and worldwide, resulting in severe visual impairment. We studied the host immune response towards A. flavus in immortalised human corneal epithelial cells (HCEC) and found increased expression of Toll-like receptors, antimicrobial peptides and proinflammatory cytokines like IL-6 and IL-8. Differential expressions of antimicrobial peptides were determined in corneal scrapings from A. flavus keratitis patients with significantly increased expression of LL-37, S100A12 and RNase 7. Increased levels of IL-22 expression were observed both in patients with A. flavus keratitis and in experimental mice model of corneal infections along with IL-17, IL-23 and IL-18. IL-22 is an important mediator of inflammation during microbial infections, and acts primarily on fibroblasts and epithelial cells. We observed constitutive expression of IL-22 receptors in HCEC, and IL-22 mediated activation of NF-κB, MAPK pathways and STAT3, along with increased expression of antimicrobial peptides in these cells. IL-22 also efficiently lessened cell deaths in corneal epithelial cells during A. flavus infection in vitro. Furthermore, recombinant IL-22 reduced fungal burden and corneal opacity in an experimental murine model of A. flavus keratitis.
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Affiliation(s)
| | - Prerana Sharma
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, India
- Department of Animal Sciences, University of Hyderabad, Hyderabad, India
| | | | - Sanhita Roy
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, India
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10
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Jadi PK, Sharma P, Bhogapurapu B, Roy S. Alternative Therapeutic Interventions: Antimicrobial Peptides and Small Molecules to Treat Microbial Keratitis. Front Chem 2021; 9:694998. [PMID: 34458234 PMCID: PMC8386189 DOI: 10.3389/fchem.2021.694998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/02/2021] [Indexed: 01/10/2023] Open
Abstract
Microbial keratitis is a leading cause of blindness worldwide and results in unilateral vision loss in an estimated 2 million people per year. Bacteria and fungus are two main etiological agents that cause corneal ulcers. Although antibiotics and antifungals are commonly used to treat corneal infections, a clear trend with increasing resistance to these antimicrobials is emerging at rapid pace. Extensive research has been carried out to determine alternative therapeutic interventions, and antimicrobial peptides (AMPs) are increasingly recognized for their clinical potential in treating infections. Small molecules targeted against virulence factors of the pathogens and natural compounds are also explored to meet the challenges and growing demand for therapeutic agents. Here we review the potential of AMPs, small molecules, and natural compounds as alternative therapeutic interventions for the treatment of corneal infections to combat antimicrobial resistance. Additionally, we have also discussed about the different formats of drug delivery systems for optimal administration of drugs to treat microbial keratitis.
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Affiliation(s)
- Praveen Kumar Jadi
- Prof, Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, India
| | - Prerana Sharma
- Prof, Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, India
- Department of Animal Sciences, University of Hyderabad, Hyderabad, India
| | - Bharathi Bhogapurapu
- Prof, Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, India
| | - Sanhita Roy
- Prof, Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, India
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Weight CM, Jochems SP, Adler H, Ferreira DM, Brown JS, Heyderman RS. Insights Into the Effects of Mucosal Epithelial and Innate Immune Dysfunction in Older People on Host Interactions With Streptococcus pneumoniae. Front Cell Infect Microbiol 2021; 11:651474. [PMID: 34113578 PMCID: PMC8185287 DOI: 10.3389/fcimb.2021.651474] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 05/10/2021] [Indexed: 12/21/2022] Open
Abstract
In humans, nasopharyngeal carriage of Streptococcus pneumoniae is common and although primarily asymptomatic, is a pre-requisite for pneumonia and invasive pneumococcal disease (IPD). Together, these kill over 500,000 people over the age of 70 years worldwide every year. Pneumococcal conjugate vaccines have been largely successful in reducing IPD in young children and have had considerable indirect impact in protection of older people in industrialized country settings (herd immunity). However, serotype replacement continues to threaten vulnerable populations, particularly older people in whom direct vaccine efficacy is reduced. The early control of pneumococcal colonization at the mucosal surface is mediated through a complex array of epithelial and innate immune cell interactions. Older people often display a state of chronic inflammation, which is associated with an increased mortality risk and has been termed 'Inflammageing'. In this review, we discuss the contribution of an altered microbiome, the impact of inflammageing on human epithelial and innate immunity to S. pneumoniae, and how the resulting dysregulation may affect the outcome of pneumococcal infection in older individuals. We describe the impact of the pneumococcal vaccine and highlight potential research approaches which may improve our understanding of respiratory mucosal immunity during pneumococcal colonization in older individuals.
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Affiliation(s)
- Caroline M. Weight
- Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Simon P. Jochems
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Hugh Adler
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Tropical and Infectious Diseases Unit, Liverpool University Hospitals National Health Service (NHS) Foundation Trust, Liverpool, United Kingdom
| | - Daniela M. Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jeremy S. Brown
- Respiratory Medicine, University College London, London, United Kingdom
| | - Robert S. Heyderman
- Research Department of Infection, Division of Infection and Immunity, University College London, London, United Kingdom
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12
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Antimicrobial nanomedicine for ocular bacterial and fungal infection. Drug Deliv Transl Res 2021; 11:1352-1375. [PMID: 33840082 DOI: 10.1007/s13346-021-00966-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2021] [Indexed: 12/13/2022]
Abstract
Ocular infection induced by bacteria and fungi is a major cause of visual impairment and blindness. Topical administration of antibiotics remains the first-line treatment, as effective eradication of pathogens is the core of the anti-infection strategy. Whereas, eye drops lack efficiency and have relatively low bioavailability. Intraocular injection may cause concurrent ocular damage and secondary infection. In addition, antibiotic-based management can be limited by the low sensitivity to multidrug-resistant bacteria. Nanomedicine is proposed as a prospective, effective, and noninvasive platform to mediate ocular delivery and combat pathogen or even resistant strains. Nanomedicine can not only carry antimicrobial agents to fight against pathogens but also directly active microbicidal capability, killing pathogens. More importantly, by modification, nanomedicine can achieve enhanced residence time and release time on the cornea, and easy penetration through corneal tissues into anterior and posterior segments of the eye, thus improving the therapeutic effect for ocular infection. In this review, several categories of antimicrobial nanomedicine are systematically discussed, where the efficiency and possibility of further embellishment and improvement to adapt to clinical use are also investigated. All in all, novel antimicrobial nanomedicine provides potent and prospective ways to manage severe and refractory ocular infections.
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13
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Sharma P, Elofsson M, Roy S. Attenuation of Pseudomonas aeruginosa infection by INP0341, a salicylidene acylhydrazide, in a murine model of keratitis. Virulence 2021; 11:795-804. [PMID: 32507000 PMCID: PMC7567437 DOI: 10.1080/21505594.2020.1776979] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
PSEUDOMONAS AERUGINOSA is an opportunistic pathogen and a major cause of corneal infections worldwide. The bacterium secretes several toxins through its type III secretion system (T3SS) to subvert host immune responses. In addition, it is armed with intrinsic as well as acquired antibiotic resistance mechanisms that make treatment a significant challenge and new therapeutic interventions are needed. Type III secretion inhibitors have been studied as an alternative or in accompaniment to traditional antibiotics to inhibit virulence of bacteria. In this study, INP0341, a T3SS inhibitor, inhibited cytotoxicity by P. aeruginosa toward human corneal epithelial cells (HCEC) at 100 μM without affecting bacterial growth in the liquid media. An increased expression of antimicrobial peptides and reactive oxygen species generation was also observed in cells exposed to P. aeruginosa in the presence of INP0341. Furthermore, INP0341 efficiently attenuated corneal infection by P. aeruginosa in an experimental model of murine keratitis as evident from corneal opacity, clinical score and bacterial load. Thus, INP0341 appears to be a promising candidate to treat corneal infection caused by P. aeruginosa and can be further considered as an alternative therapeutic intervention.
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Affiliation(s)
- Prerana Sharma
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute , Hyderabad, India.,Department of Animal Biology, University of Hyderabad , Hyderabad, India
| | | | - Sanhita Roy
- Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute , Hyderabad, India
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14
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Aspergillus fumigatus-Stimulated Human Corneal Epithelial Cells Induce Pyroptosis of THP-1 Macrophages by Secreting TSLP. Inflammation 2020; 44:682-692. [PMID: 33118609 DOI: 10.1007/s10753-020-01367-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/02/2020] [Accepted: 10/15/2020] [Indexed: 12/22/2022]
Abstract
Fungal keratitis (FK) is a keratopathy caused by pathogenic fungal infection. The aim of this work is to explore the role of thymic stromal lymphopoietin (TSLP) in FK. Human corneal epithelial cells (HCECs) were treated with Aspergillus fumigatus hyphae, and we found that TSLP was highly expressed and secreted in the hyphae-treated HCECs. Hyphae-treated HCECs or TSLP treatment enhanced the expression of caspase-1 P20, GSDMD-N (p30), IL-1β, and IL-18 in the human THP-1 macrophages. The influence conferred by hyphae-treated HCECs or TSLP treatment was rescued by TSLP neutralizing antibody or VX-765 (caspase-1 inhibitor) treatment. Moreover, TSLP treatment promoted the expression of NLRP3, ASC, caspase-1 P20, GSDMD-N (p30), IL-1β, and IL-18 in the THP-1 macrophages, which was abolished by NLRP3 knockdown. Furthermore, TSLPR silencing suppressed the expression of NLRP3, ASC, caspase-1 P20, GSDMD-N (p30), IL-1β, and IL-18 in the TSLP-treated THP-1 macrophages. In conclusion, our article confirms that Aspergillus fumigatus-stimulated HCECs induce pyroptosis of THP-1 macrophages by secreting TSLP. TSLP/TSLPR induces caspase-1-dependent pyroptosis through activation of NLRP3 inflammasome. Thus, our work suggests that TSLP may be a potential target for FK treatment.
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