Natriuretic peptide system in the human retina

[摘要] Purpose: The natriuretic peptide (NP) family includes atrialnatriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-typenatriuretic peptide (CNP). Natriuretic peptides are known to inhibitvascular cell growth and regulate vessel tone. There is also muchevidence to suggest they modulate vascular permeability andangiogenesis, as well as regulating aqueous humor production in the eye.All these data indicate that the natriuretic peptide system might beinvolved in the development of diabetic retinopathy and glaucoma. Giventhe expression pattern of natriuretic peptides (NPs) and theirreceptors, natriuretic peptide receptor A (NPRA), natriuretic peptidereceptor B (NPRB) and natriuretic peptide receptor C (NPRC) in the humanretina has not yet been established, the present study was designed todetermine ANP, BNP and CNP gene expression and localize the maturepeptides in this tissue. The expression pattern of the genes encodingthe different NP receptor subtypes was also examined.Methods: Eyes (n=10) from human donors with no history of eyedisease were fixed and processed for routine paraffin embedding. Thecellular location of the NPs was established by immunohistochemistry.Real-time quantitative reverse transcription-polymerase chain reaction(RT-PCR) was used to evaluate the expression of NP and NP receptor genesin neural retinas obtained from the contralateral eyes.Results: Immunohistochemistry revealed the presence of NPs in theneural retina and retinal pigment epithelium. Positive NP immunostainingwas observed within the astrocytes and in their processes envelopingvessels. In the anterior portion of the optic nerve, NPs were intenselylabeled in neural bundles. We were able to detect NP gene expression inthe human retina. The levels of NP receptor-encoding transcriptsdetected indicated no significant differential expression of genescoding for the different receptor subtypes.Conclusions: Our finding that NP receptor transcripts are expressedalong with ANP, BNP, and CNP mRNA in the human retina provides evidencefor a local system in this tissue. The expression of NPs in neuralretinal, glial, and vascular elements of the normal adult retinasuggests a role for these peptides in maintaining both the neural andvascular integrity of the mature retina.

[学科分类] 生物化学/生物物理