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Chen X, Li Y, Lu L, Wu J, Yan R, Xiang J, Fan Q, Liu J, Li S, Xue Y, Fu T, Liu J, Li Z. Activation of the SST-SSTR5 signaling pathway enhances corneal wound healing in diabetic mice. Mucosal Immunol 2024:S1933-0219(24)00051-5. [PMID: 38866206 DOI: 10.1016/j.mucimm.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 04/23/2024] [Accepted: 06/04/2024] [Indexed: 06/14/2024]
Abstract
Corneal wound healing in diabetic patients is usually delayed and accompanied by excessive inflammation. However, the underlying cellular and molecular mechanisms remain poorly understood. Here, we found that somatostatin (SST), an immunosuppressive peptide produced by corneal nerve fibers, was significantly reduced in streptozotocin-induced diabetic mice. In addition, we discovered that topical administration of exogenous SST significantly improved re-epithelialization and nerve regeneration following diabetic corneal epithelial abrasion. Further analysis showed that topical SST significantly reduced the expression of injury inflammation-related genes, inhibited neutrophil infiltration, and shifted macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 in diabetic corneas' healing. Moreover, the application of L-817,818, an agonist of the SST receptor type 5 subtype, significantly reduced the inflammatory response following epithelial injury and markedly improved the process of re-epithelialization and nerve regeneration in mice. Taken together, these data suggest that activation of the SST-SST receptor type 5 pathway significantly ameliorates diabetes-induced abnormalities in corneal wound repair in mice. Targeting this pathway may provide a novel strategy to restore impaired corneal wound closure and nerve regeneration in diabetic patients.
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Affiliation(s)
- Xinwei Chen
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Yan Li
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China; Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Liyuan Lu
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China; Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Jiaxin Wu
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China; Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Ruyu Yan
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China; Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Jiayan Xiang
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China; Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Qiwei Fan
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Jiangman Liu
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Senmao Li
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Yunxia Xue
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Ting Fu
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Jun Liu
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China; Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, China; Guangdong-Hong Kong-Macau Great Bay Area Geroscience Joint Laboratory, School of Medicine, Jinan University, Guangzhou, China.
| | - Zhijie Li
- International Ocular Surface Research Center, Institute of Ophthalmology, and Key Laboratory for Regenerative Medicine, School of Medicine, Jinan University, Guangzhou, China; Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, China.
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Puri S, Kenyon BM, Hamrah P. Immunomodulatory Role of Neuropeptides in the Cornea. Biomedicines 2022; 10:1985. [PMID: 36009532 PMCID: PMC9406019 DOI: 10.3390/biomedicines10081985] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 12/21/2022] Open
Abstract
The transparency of the cornea along with its dense sensory innervation and resident leukocyte populations make it an ideal tissue to study interactions between the nervous and immune systems. The cornea is the most densely innervated tissue of the body and possesses both immune and vascular privilege, in part due to its unique repertoire of resident immune cells. Corneal nerves produce various neuropeptides that have a wide range of functions on immune cells. As research in this area expands, further insights are made into the role of neuropeptides and their immunomodulatory functions in the healthy and diseased cornea. Much remains to be known regarding the details of neuropeptide signaling and how it contributes to pathophysiology, which is likely due to complex interactions among neuropeptides, receptor isoform-specific signaling events, and the inflammatory microenvironment in disease. However, progress in this area has led to an increase in studies that have begun modulating neuropeptide activity for the treatment of corneal diseases with promising results, necessitating the need for a comprehensive review of the literature. This review focuses on the role of neuropeptides in maintaining the homeostasis of the ocular surface, alterations in disease settings, and the possible therapeutic potential of targeting these systems.
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Affiliation(s)
- Sudan Puri
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Brendan M. Kenyon
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Pedram Hamrah
- Center for Translational Ocular Immunology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA 02111, USA
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
- Departments of Immunology and Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
- Cornea Service, Tufts New England Eye Center, Boston, MA 02111, USA
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Jüngert K, Paulsen F, Jacobi C, Horwath-Winter J, Garreis F. Prolactin Inducible Protein, but Not Prolactin, Is Present in Human Tears, Is Involved in Tear Film Quality, and Influences Evaporative Dry Eye Disease. Front Med (Lausanne) 2022; 9:892831. [PMID: 35847789 PMCID: PMC9279896 DOI: 10.3389/fmed.2022.892831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/27/2022] [Indexed: 11/30/2022] Open
Abstract
Purpose Decreased production of the aqueous component of the tear film is an important cause of the development of dry eye disease (DED). Tear production is influenced by hormones and hormone-like factors. Prolactin (PLR), a multifunctional pituitary gland hormone, is regularly present in the lacrimal gland of rats and rabbits. In humans, serum PLR concentration correlates with tear quality. To gain deeper insights of possible effects of PRL, prolactin receptor (PRLR) and prolactin inducible protein (PIP), we analyzed the three proteins in the human lacrimal apparatus and in reflex tears of healthy volunteers as well as patients suffering from DED. Methods Gene expression of PRLR and PIP was analyzed by RT-PCR in cadaveric human lacrimal gland and ocular surface tissues, immortalized human corneal epithelial cells (HCE and hTEPI) and human Meibomian gland epithelial cells (HMGECs). At the protein level, the expression and localization of PRL, PRLR and PIP in formalin-fixed paraffin sections of the lacrimal apparatus were studied by immunohistochemistry. In addition, tear fluid from DED patients and healthy volunteers was analyzed by ELISA to determine the concentration of PRL and PIP. Results RT-PCR analyses revealed gene expression of PRLR and PIP in human tissue samples of cornea, lacrimal glands, and eyelids, whereas only PIP, but not PRLR, was detectable in immortalized corneal epithelial cells. Immunohistochemistry revealed for the first time the expression and localization of PRL, PRLR, and PIP in human tissues of the lacrimal apparatus and at the ocular surface. PRL and PRLR were detectable in corneal epithelium, lacrimal glands, and Meibomian glands. Reflex tears from DED patients revealed significantly increased PIP concentrations, whereas PRL was undetectable in tears of DED patients and healthy volunteers. Conclusion PRL, PRLR, and PIP are found in the lacrimal apparatus and on the ocular surface. PIP, but not PRL, is present in human tears and appears to be involved in the physiology of tear film quality. Our clinical data revealed that PIP may affect tear quality, but further functional analyses are needed to fully elucidate the effects of PRL and PIP-associated factors in tear secretion as well as in the connection of DED.
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Affiliation(s)
- Katharina Jüngert
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Friedrich Paulsen
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Christina Jacobi
- Eyes and Skin Practice Dr. Jacobi, Nürnberg, Germany
- Department of Ophthalmology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | | | - Fabian Garreis
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
- *Correspondence: Fabian Garreis
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