Dexamethasone intravitreal implant downregulates PDGFR-α and upregulates caveolin-1 in experimental branch retinal

Lasse Jørgensen Cehofski1, Anders Kruse2, Sigriður Olga Magnusdottir3

  • 1Department of Ophthalmology, Aalborg University Hospital, Aalborg, Denmark; Biomedical Research Laboratory, Aalborg University Hospital, Aalborg, Denmark; Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.

A dexamethasone (DEX) intravitreal implant (OZURDEX) provides an effective treatment of inflammation secondary to branch retinal vein occlusion (BRVO). Retinal proteome changes which mediate the beneficial effects of the implant remain poorly understood. To study retinal proteome changes in BRVO following an intervention with a DEX implant this study combined an experimental model of BRVO with proteomic techniques. In eight Danish Landrace pigs experimental BRVO was induced in both eyes using argon laser. After inducing BRVO a DEX implant was injected into the right eye of each animal while the left control eye was given an identical injection without an implant. Fifteen days after BRVO and DEX implant intervention the retinas were excised and analyzed with tandem mass tag based mass spectrometry. A total of 26 significantly changed proteins were identified. DEX intervention reduced the retinal levels of platelet-derived growth factor receptor-α (PDGFR-α) and vascular endothelial growth factor receptor 2 (VEGFR-2). DEX treatment resulted in increased levels of caveolin-1, peptidyl-prolyl cis-trans isomerase FKBP5 and transgelin. Changes in PDGFR-α and caveolin-1 were confirmed with immunohistochemistry. In BRVO treated with the DEX implant a strong reaction for caveolin-1 was observed in the innermost retinal layers. DEX implant intervention may inhibit PDGF signaling by decreasing the retinal level of PDGFR-α while an increased content of caveolin-1 may help maintain the integrity of the blood-retinal barrier.

Related Concept Videos

Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR...
2.9K
Veins01:17

Veins

Veins are an integral part of our circulatory system, serving as the blood vessels that transport blood from all body regions to the heart. They are a network of hollow tubes that carry blood low in oxygen from the body's cells back to the heart for reoxygenation. Veins are crucial for maintaining the body's overall fluid balance and the continuous circulation of blood.
Structure of Veins:
The structure of veins is specifically designed to assist in the low-pressure transportation of...
9.0K
Veins of Thorax01:19

Veins of Thorax

The azygos system is a crucial part of the body's circulatory system and drains most of the thorax. It comprises the azygos, hemiazygos, and accessory hemiazygos veins.
The azygos vein, positioned just right of the midline and anterior to the vertebral column, begins at the junction of the right ascending lumbar and subcostal veins, terminating in the superior vena cava. This vein drains blood from the right side of the thoracic wall, thoracic viscera, and posterior abdominal wall.
The...
2.1K
Veins of Lower Limbs01:15

Veins of Lower Limbs

The human body consists of an intricate network of veins responsible for the crucial task of blood drainage from the lower limbs. These veins can be categorized into two main types: deep veins and superficial veins.
Formed by the union of the medial and lateral plantar veins, the posterior tibial vein, rising through the calf muscle, assimilates the fibular vein. The anterior tibial vein, a superior extension of the foot's dorsalis pedis vein, merges with the posterior tibial vein at the...
2.6K
Mass Spectrometry: Branched Alkane Fragmentation01:29

Mass Spectrometry: Branched Alkane Fragmentation

This lesson delves into the mass spectrometry of branched alkane fragmentation. Branched alkanes possess secondary or tertiary carbon atoms, which generate relatively stable carbocations if the cleavage occurs at the branching point. The high stability of carbocations drives the instant fragmentation of branched alkanes. Accordingly, the branched alkane's molecular ion peak is very weak or invisible in the mass spectra, especially in comparison to a linear alkane.
1.8K
Generation of Straight or Branched Actin Filaments01:14

Generation of Straight or Branched Actin Filaments

The straight or branched structure formation of actin filaments is controlled by nucleating proteins such as the formins and Arp2/3 complex. Formin-mediated assembly results in straight filaments, whereas Arp2/3 protein complex-mediated assembly results in branched actin filaments.
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...
3.8K