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Ling Y, Wang Y, Ye J, Luan C, Bi A, Gu Y, Shi X. Changes in Intrinsically Photosensitive Retinal Ganglion Cells, Dopaminergic Amacrine Cells, and Their Connectivity in the Retinas of Lid Suture Myopia. Invest Ophthalmol Vis Sci 2024; 65:8. [PMID: 39230992 PMCID: PMC11379095 DOI: 10.1167/iovs.65.11.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2024] Open
Abstract
Purpose This study investigates alterations in intrinsically photosensitive retinal ganglion cells (ipRGCs) and dopaminergic amacrine cells (DACs) in lid suture myopia (LSM) rats. Methods LSM was induced in rats by suturing the right eyes for 4 weeks. Double immunofluorescence staining of ipRGCs and DACs in whole-mount retinas was performed to analyze changes in the density and morphology of control, LSM, and fellow eyes. Real-time quantitative PCR and Western blotting were used to detect related genes and protein expression levels. Results Significant myopia was induced in the lid-sutured eye, but the fellow eye was not different to control. Decreased ipRGC density with paradoxically increased overall melanopsin expression and enlarged dendritic beads was observed in both the LSM and fellow eyes of the LSM rat retinas. In contrast, DAC changes occurred only in the LSM eyes, with reduced DAC density and tyrosine hydroxylase (TH) expression, sparser dendritic processes, and fewer varicosities. Interestingly, contacts between ipRGCs and DACs in the inner plexiform layer (IPL) and the expression of pituitary adenylate cyclase-activating polypeptide (PACAP) and vesicular monoamine transporter protein 2 (VMAT2) mRNA were decreased in the LSM eyes. Conclusions The ipRGCs and DACs in LSM rat retinas undergo multiple alterations in density, morphology, and related molecule expressions. However, the ipRGC changes alone appear not to be required for the development of myopia, given that myopia is only induced in the lid-sutured eye, and they are unlikely alone to drive the DAC changes. Reduced contacts between ipRGCs and DACs in the LSM eyes may be the structural foundation for the impaired signaling between them. PACAP and VMAT2, strongly associated with ipRGCs and DACs, may play important roles in LSM through complex mechanisms.
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Affiliation(s)
- Ying Ling
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, China
- Medical College of Optometry and Ophthalmology, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yao Wang
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Jingjing Ye
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, China
- Medical College of Optometry and Ophthalmology, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Changlin Luan
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Ailing Bi
- Medical College of Optometry and Ophthalmology, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yu Gu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Xuefeng Shi
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
- Institute of Ophthalmology, Nankai University, Tianjin, China
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Fang Y, Wang Q, Li Y, Zeng L, Liu J, Ou K. On implications of somatostatin in diabetic retinopathy. Neural Regen Res 2024; 19:1984-1990. [PMID: 38227526 DOI: 10.4103/1673-5374.390955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 10/10/2023] [Indexed: 01/17/2024] Open
Abstract
Somatostatin, a naturally produced neuroprotective peptide, depresses excitatory neurotransmission and exerts anti-proliferative and anti-inflammatory effects on the retina. In this review, we summarize the progress of somatostatin treatment of diabetic retinopathy through analysis of relevant studies published from February 2019 to February 2023 extracted from the PubMed and Google Scholar databases. Insufficient neuroprotection, which occurs as a consequence of declined expression or dysregulation of retinal somatostatin in the very early stages of diabetic retinopathy, triggers retinal neurovascular unit impairment and microvascular damage. Somatostatin replacement is a promising treatment for retinal neurodegeneration in diabetic retinopathy. Numerous pre-clinical and clinical trials of somatostatin analog treatment for early diabetic retinopathy have been initiated. In one such trial (EUROCONDOR), topical administration of somatostatin was found to exert neuroprotective effects in patients with pre-existing retinal neurodysfunction, but had no impact on the onset of diabetic retinopathy. Overall, we concluded that somatostatin restoration may be especially beneficial for the growing population of patients with early-stage retinopathy. In order to achieve early prevention of diabetic retinopathy initiation, and thereby salvage visual function before the appearance of moderate non-proliferative diabetic retinopathy, several issues need to be addressed. These include the needs to: a) update and standardize the retinal screening scheme to incorporate the detection of early neurodegeneration, b) identify patient subgroups who would benefit from somatostatin analog supplementation, c) elucidate the interactions of somatostatin, particularly exogenously-delivered somatostatin analogs, with other retinal peptides in the context of hyperglycemia, and d) design safe, feasible, low cost, and effective administration routes.
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Affiliation(s)
- Yanhong Fang
- Department of Ophthalmology, Chongqing University Jiangjin Hospital, Chongqing, China
| | - Qionghua Wang
- Department of Ophthalmology, Chongqing University Jiangjin Hospital, Chongqing, China
| | - Youjian Li
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, China
| | - Li Zeng
- Shandong Provincial Hospital, Shandong Laboratory Animal Center, Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong Province, China
| | - Jian Liu
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Kepeng Ou
- College of Pharmacy, National & Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, IATTI, Chongqing University of Arts and Sciences, Chongqing, China
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Denes V, Lukats A, Szarka G, Subicz R, Mester A, Kovacs-Valasek A, Geck P, Berta G, Herczeg R, Postyeni E, Gyenesei A, Gabriel R. Long-term Effects of the pituitary-adenylate cyclase-activating Polypeptide (PACAP38) in the Adult Mouse Retina: Microglial Activation and Induction of Neural Proliferation. Neurochem Res 2023; 48:3430-3446. [PMID: 37466802 PMCID: PMC10514177 DOI: 10.1007/s11064-023-03989-7] [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: 04/06/2023] [Revised: 07/01/2023] [Accepted: 07/07/2023] [Indexed: 07/20/2023]
Abstract
The degenerative retinal disorders characterized by progressive cell death and exacerbating inflammation lead ultimately to blindness. The ubiquitous neuropeptide, PACAP38 is a promising therapeutic agent as its proliferative potential and suppressive effect on microglia might enable cell replacement and attenuate inflammation, respectively. Our previous finding that PACAP38 caused a marked increase of the amacrine cells in the adult (1-year-old) mouse retina, served as a rationale of the current study. We aimed to determine the proliferating elements and the inflammatory status of the PACAP38-treated retina. Three months old mice were intravitreally injected with 100 pmol PACAP38 at 3 months intervals (3X). Retinas of 1-year-old animals were dissected and effects on cell proliferation, and expression of inflammatory regulators were analyzed. Interestingly, both mitogenic and anti-mitogenic actions were detected after PACAP38-treatment. Further analysis of the mitogenic effect revealed that proliferating cells include microglia, endothelial cells, and neurons of the ganglion cell layer but not amacrine cells. Furthermore, PACAP38 stimulated retinal microglia to polarize dominantly into M2-phenotype but also might cause subsequent angiogenesis. According to our results, PACAP38 might dampen pro-inflammatory responses and help tissue repair by reprogramming microglia into an M2 phenotype, nonetheless, with angiogenesis as a warning side effect.
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Affiliation(s)
- Viktoria Denes
- Department of Neurobiology, University of Pécs, 6 Ifjúság str, Pécs, H-7624, Hungary.
| | - Akos Lukats
- Institute of Translational Medicine, Translational Retina Research Group, Semmelweis University, Budapest, Hungary
| | - Gergely Szarka
- Department of Neurobiology, University of Pécs, 6 Ifjúság str, Pécs, H-7624, Hungary
| | - Rovena Subicz
- Department of Neurobiology, University of Pécs, 6 Ifjúság str, Pécs, H-7624, Hungary
| | - Adrienn Mester
- Department of Neurobiology, University of Pécs, 6 Ifjúság str, Pécs, H-7624, Hungary
| | - Andrea Kovacs-Valasek
- Department of Neurobiology, University of Pécs, 6 Ifjúság str, Pécs, H-7624, Hungary
| | - Peter Geck
- Department of Medical Education, School of Medicine, Tufts University, 136 Harrison Ave, Boston, MA, 02111, USA
| | - Gergely Berta
- Department of Medical Biology and Central Electron Microscope Laboratory, Medical School, University of Pécs, Pécs, Hungary
| | - Robert Herczeg
- János Szentágothai Research Centre, Bioinformatics Research Group, University of Pécs, 20 Ifjúság str, Pécs, H-7624, Hungary
| | - Etelka Postyeni
- Department of Neurobiology, University of Pécs, 6 Ifjúság str, Pécs, H-7624, Hungary
| | - Attila Gyenesei
- János Szentágothai Research Centre, Bioinformatics Research Group, University of Pécs, 20 Ifjúság str, Pécs, H-7624, Hungary
| | - Robert Gabriel
- Department of Neurobiology, University of Pécs, 6 Ifjúság str, Pécs, H-7624, Hungary
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D'Amico AG, Maugeri G, Magrì B, Lombardo C, Saccone S, Federico C, Cavallaro P, Giunta S, Bucolo C, D'Agata V. PACAP-ADNP axis prevents outer retinal barrier breakdown and choroidal neovascularization by interfering with VEGF secreted from retinal pigmented epitelium cells. Peptides 2023; 168:171065. [PMID: 37495040 DOI: 10.1016/j.peptides.2023.171065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/17/2023] [Accepted: 07/23/2023] [Indexed: 07/28/2023]
Abstract
During diabetic retinopathy (DR) progression, the retina undergoes various metabolic changes, including hypoxia-signalling cascade induction in the cells of retinal pigmented epithelium (RPE). The overexpression of hypoxic inducible factors causes transcription of many target genes including vascular endothelial growth factor (VEGF). The RPE cells form the outer blood retinal barrier (oBRB), a specialized structure that regulates ions and metabolites flux into the retina to maintain a suitable quality of its extracellular microenvironment. VEGF worsens retinal condition since its secretion from the basolateral compartment of RPE cells compromises the barrier's integrity and induces choroidal neovascularization. In this work, we hypothesized that PACAP prevents the damage to oBRB and controls choroidal neovascularization through the induction of ADNP. Firstly, we demonstrated that ADNP is expressed in Streptozotocin (STZ)-induced diabetic animals. To validate our hypothesis, we cultured endothelial cells (H5V) forming vessels-like structures, in a conditioned medium (CM) derived from ARPE-19 cells exposed to hyperglycaemic/hypoxic insult, containing a known VEGF concentration. The involvement of PACAP-ADNP axis on oBRB integrity was evaluated through the measurement of trans-epithelial-electrical resistance and permeability assay performed on ARPE cell monolayer cultured in CM and by analysing the expression of two tight junction forming proteins, ZO1 and occludin. By culturing H5V in CM, we demonstrated that PACAP-ADNP axis counteracted vessels-like structures formation promoted by VEGF. In conclusion, the results suggested a primary role of PACAP/ADNP axis in preventing oBRB damage and in controlling aberrant choroidal neovascularization induced by VEGF secreted from RPE cells exposed to hyperglycaemia/hypoxic insult in DR.
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Affiliation(s)
- Agata Grazia D'Amico
- Department of Drug and Health Sciences, Section of System Biology, University of Catania, 95125 Catania, Italy
| | - Grazia Maugeri
- Department of Biomedical and Biotechnological Sciences, Section of Anatomy, Histology and Movement Sciences, University of Catania, 95100 Catania, Italy
| | - Benedetta Magrì
- Department of Biomedical and Biotechnological Sciences, Section of Anatomy, Histology and Movement Sciences, University of Catania, 95100 Catania, Italy
| | - Claudia Lombardo
- Department of Biomedical and Biotechnological Sciences, Section of Anatomy, Histology and Movement Sciences, University of Catania, 95100 Catania, Italy
| | - Salvatore Saccone
- Department of Biological, Geological and Environmental Sciences, Section of Animal Biology, University of Catania, 95123 Catania, Italy
| | - Concetta Federico
- Department of Biological, Geological and Environmental Sciences, Section of Animal Biology, University of Catania, 95123 Catania, Italy
| | - Paola Cavallaro
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", University of Messina, Italy
| | - Salvatore Giunta
- Department of Biomedical and Biotechnological Sciences, Section of Anatomy, Histology and Movement Sciences, University of Catania, 95100 Catania, Italy
| | - Claudio Bucolo
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy; Center for Research in Ocular Pharmacology-CERFO, University of Catania, Catania, Italy
| | - Velia D'Agata
- Department of Biomedical and Biotechnological Sciences, Section of Anatomy, Histology and Movement Sciences, University of Catania, 95100 Catania, Italy; Center for Research in Ocular Pharmacology-CERFO, University of Catania, Catania, Italy.
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Kovács-Valasek A, Rák T, Pöstyéni E, Csutak A, Gábriel R. Three Major Causes of Metabolic Retinal Degenerations and Three Ways to Avoid Them. Int J Mol Sci 2023; 24:ijms24108728. [PMID: 37240082 DOI: 10.3390/ijms24108728] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
An imbalance of homeostasis in the retina leads to neuron loss and this eventually results in a deterioration of vision. If the stress threshold is exceeded, different protective/survival mechanisms are activated. Numerous key molecular actors contribute to prevalent metabolically induced retinal diseases-the three major challenges are age-related alterations, diabetic retinopathy and glaucoma. These diseases have complex dysregulation of glucose-, lipid-, amino acid or purine metabolism. In this review, we summarize current knowledge on possible ways of preventing or circumventing retinal degeneration by available methods. We intend to provide a unified background, common prevention and treatment rationale for these disorders and identify the mechanisms through which these actions protect the retina. We suggest a role for herbal medicines, internal neuroprotective substances and synthetic drugs targeting four processes: parainflammation and/or glial cell activation, ischemia and related reactive oxygen species and vascular endothelial growth factor accumulation, apoptosis and/or autophagy of nerve cells and an elevation of ocular perfusion pressure and/or intraocular pressure. We conclude that in order to achieve substantial preventive or therapeutic effects, at least two of the mentioned pathways should be targeted synergistically. A repositioning of some drugs is considered to use them for the cure of the other related conditions.
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Affiliation(s)
- Andrea Kovács-Valasek
- Department of Experimental Zoology and Neurobiology, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
| | - Tibor Rák
- Department of Ophthalmology, Medical School, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - Etelka Pöstyéni
- Department of Experimental Zoology and Neurobiology, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
| | - Adrienne Csutak
- Department of Ophthalmology, Medical School, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - Robert Gábriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
- János Szentágothai Research Centre, University of Pécs, Ifjúság útja 20, 7624 Pécs, Hungary
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6
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Toth D, Reglodi D, Schwieters L, Tamas A. Role of endocrine PACAP in age-related diseases. Front Endocrinol (Lausanne) 2023; 14:1118927. [PMID: 36967746 PMCID: PMC10033946 DOI: 10.3389/fendo.2023.1118927] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/24/2023] [Indexed: 03/11/2023] Open
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a conserved neuropeptide, which confers diverse anti-aging endocrine and paracrine/autocrine effects, including anti-apoptotic, anti-inflammatory and antioxidant action. The results of the in vivo and in vitro experiments show that increasing emphasis is being placed on the diagnostic/prognostic biomarker potential of this neuropeptide in a wide array of age-related diseases. After the initial findings regarding the presence and alteration of PACAP in different body fluids in physiological processes, an increasing number of studies have focused on the changes of its levels in various pathological conditions associated with advanced aging. Until 2016 - when the results of previous human studies were reviewed - a vast majority of the studies had dealt with age-related neurological diseases, like cerebrovascular and neurodegenerative diseases, multiple sclerosis, as well as some other common diseases in elderly such as migraine, traumatic brain injury and post-traumatic stress disorder, chronic hepatitis and nephrotic syndrome. The aim of this review is to summarize the old and the new results and highlight those 'classical' and emerging clinical fields in which PACAP may become subject to further investigation as a diagnostic and/or prognostic biomarker in age-related diseases.
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Affiliation(s)
- Denes Toth
- Department of Forensic Medicine, University of Pécs Medical School, Pécs, Hungary
| | - Dora Reglodi
- Department of Anatomy, ELKH-PTE PACAP Research Team, Centre for Neuroscience, University of Pécs Medical School, Pécs, Hungary
| | - Lili Schwieters
- Department of Anatomy, ELKH-PTE PACAP Research Team, Centre for Neuroscience, University of Pécs Medical School, Pécs, Hungary
| | - Andrea Tamas
- Department of Anatomy, ELKH-PTE PACAP Research Team, Centre for Neuroscience, University of Pécs Medical School, Pécs, Hungary
- *Correspondence: Andrea Tamas,
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7
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Patko E, Szabo E, Toth D, Tornoczky T, Bosnyak I, Vaczy A, Atlasz T, Reglodi D. Distribution of PACAP and PAC1 Receptor in the Human Eye. J Mol Neurosci 2022; 72:2176-2187. [PMID: 35253081 PMCID: PMC9726800 DOI: 10.1007/s12031-022-01985-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 02/08/2022] [Indexed: 12/16/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with widespread distribution and diverse biological functions. Several studies show that PACAP has strong cytoprotective effects mediated mostly through its specific PAC1 receptor (PAC1-R) and it plays important roles in several pathological conditions. Its distribution and altered expression are known in various human tissues, but there is no descriptive data about PACAP and its receptors in the human eyebulb. Since PACAP38 is the dominant form of the naturally occurring PACAP, our aim was to investigate the distribution of PACAP38-like immunoreactivity in the human eye and to describe the presence of PAC1-R. Semiquantitative evaluation was performed after routine histology and immunohistochemical labeling on human eye sections. Our results showed high level of immunopositivity in the corneal epithelium and endothelium. Within the vascular layer, the iris and the ciliary body had strong immunopositivity for both PACAP and PAC1-R. Several layers of the retina showed immunoreactivity for PACAP and PAC1-R, but the ganglion cell layer had a special pattern in the immunolabeling. Labeling was observed in the neuropil within the optic nerve in both cases and glial cells displayed immunoreactivity for PAC1-R. In summary, our study indicates the widespread occurrence of PACAP and its specific receptor in the human eye, implying that the results from in vitro and animal studies have translational value and most probably are also present in the human eye.
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Affiliation(s)
- Evelin Patko
- Department of Anatomy, Medical School, MTA-PTE PACAP Research Team, University of Pecs, 7624, Pecs, Hungary
| | - Edina Szabo
- Department of Anatomy, Medical School, MTA-PTE PACAP Research Team, University of Pecs, 7624, Pecs, Hungary
| | - Denes Toth
- Department of Forensic Medicine, Medical School, University of Pecs, 7624, Pecs, Hungary
| | - Tamas Tornoczky
- Department of Pathology, Medical School and Clinical Center, University of Pecs, 7624, Pecs, Hungary
| | - Inez Bosnyak
- Department of Anatomy, Medical School, MTA-PTE PACAP Research Team, University of Pecs, 7624, Pecs, Hungary
| | - Alexandra Vaczy
- Department of Anatomy, Medical School, MTA-PTE PACAP Research Team, University of Pecs, 7624, Pecs, Hungary
| | - Tamas Atlasz
- Department of Anatomy, Medical School, MTA-PTE PACAP Research Team, University of Pecs, 7624, Pecs, Hungary.
- Szentagothai Research Center, Medical School, University of Pecs, 7624, Pecs, Hungary.
- Department of Sportbiology, University of Pecs, 7624, Pecs, Hungary.
| | - Dora Reglodi
- Department of Anatomy, Medical School, MTA-PTE PACAP Research Team, University of Pecs, 7624, Pecs, Hungary
- Szentagothai Research Center, Medical School, University of Pecs, 7624, Pecs, Hungary
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Martínez-Villaluenga C, Hernández-Ledesma B. Peptides for Health Benefits 2020. Int J Mol Sci 2022; 23:ijms23126699. [PMID: 35743143 PMCID: PMC9223426 DOI: 10.3390/ijms23126699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 06/09/2022] [Indexed: 11/28/2022] Open
Affiliation(s)
| | - Blanca Hernández-Ledesma
- Institute of Food Science Research (CIAL, CSIC-UAM, CEI UAM + CSIC), Nicolás Cabrera 9, 28049 Madrid, Spain
- Correspondence:
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Effects of pituitary adenylate cyclase activating polypeptide (PACAP) in corneal epithelial regeneration and signal transduction in rats. Int J Pept Res Ther 2022. [DOI: 10.1007/s10989-022-10405-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
AbstractCorneal epithelium responds to insults with a rapid wound healing, which is essential for maintaining vision. The proper balance of apoptotic and proliferation-stimulating pathways is critical for normal regeneration. Pituitary adenylate cyclase activating polypeptide (PACAP) is an important growth factor during the development of the nervous system and exerts cytoprotective effects in injuries. The aim of the present study was to investigate the effects of PACAP on corneal epithelial wound healing in rats and on two important protective signaling molecules, Akt and ERK1/2, both of which have been reported to play important roles during cell survival and regeneration, including corneal wound healing. Wistar rats received PACAP treatment in form of eyedrops, containing 1, 5 and 10 µg PACAP27, immediately and every two hours after corneal abrasion. Corneas were stained with fluorescein dye and further processed for histological staining or Western blot analysis for Akt and ERK1/2 expression. Our results showed that topical PACAP application enhanced corneal wound healing, as the area of injury was significantly less in PACAP-treated groups. Furthermore, both ERK1/2 and Akt signaling was induced upon PACAP administration in both injured and intact corneas. In summary, the present results show that PACAP enhances corneal wound healing in a rat model of corneal abrasion.
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Pöstyéni E, Ganczer A, Kovács-Valasek A, Gabriel R. Relevance of Peptide Homeostasis in Metabolic Retinal Degenerative Disorders: Curative Potential in Genetically Modified Mice. Front Pharmacol 2022; 12:808315. [PMID: 35095518 PMCID: PMC8793341 DOI: 10.3389/fphar.2021.808315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/20/2021] [Indexed: 11/19/2022] Open
Abstract
The mammalian retina contains approximately 30 neuropeptides that are synthetized by different neuronal cell populations, glia, and the pigmented epithelium. The presence of these neuropeptides leaves a mark on normal retinal molecular processes and physiology, and they are also crucial in fighting various pathologies (e.g., diabetic retinopathy, ischemia, age-related pathologies, glaucoma) because of their protective abilities. Retinal pathologies of different origin (metabolic, genetic) are extensively investigated by genetically manipulated in vivo mouse models that help us gain a better understanding of the molecular background of these pathomechanisms. These models offer opportunities to manipulate gene expression in different cell types to help reveal their roles in the preservation of retinal health or identify malfunction during diseases. In order to assess the current status of transgenic technologies available, we have conducted a literature survey focused on retinal disorders of metabolic origin, zooming in on the role of retinal neuropeptides in diabetic retinopathy and ischemia. First, we identified those neuropeptides that are most relevant to retinal pathologies in humans and the two clinically most relevant models, mice and rats. Then we continued our analysis with metabolic disorders, examining neuropeptide-related pathways leading to systemic or cellular damage and rescue. Last but not least, we reviewed the available literature on genetically modified mouse strains to understand how the manipulation of a single element of any given pathway (e.g., signal molecules, receptors, intracellular signaling pathways) could lead either to the worsening of disease conditions or, more frequently, to substantial improvements in retinal health. Most attention was given to studies which reported successful intervention against specific disorders. For these experiments, a detailed evaluation will be given and the possible role of converging intracellular pathways will be discussed. Using these converging intracellular pathways, curative effects of peptides could potentially be utilized in fighting metabolic retinal disorders.
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Affiliation(s)
- Etelka Pöstyéni
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Alma Ganczer
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Andrea Kovács-Valasek
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
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