quantification-diabetes-induced-adherent-leukocytes-retinal

Quantification of Diabetes-induced Adherent Leukocytes in Retinal Vasculature

Leukostasis refers to the attachment of leukocytes to the luminal wall of the vasculature. This interaction of leukocytes with the wall of blood vessels ...

University of California, Irvine

Levels of neutrophil elastase, a serine protease secreted by neutrophils, are elevated in diabetes. The purpose of this study was to determine whether neutrophil elastase (NE) contributes to the diabetes-induced increase in retinal vascular permeability in mice with streptozotocin-induced diabetes, and, if so, to investigate the potential role of IL-17 in this process.

Neutrophil elastase contributes to the pathological vascular permeability characteristic of diabetic retinopathy.

Female mice have been found to be resistant to streptozotocin (STZ)-induced diabetes, and pre-clinical research related to diabetic complications commonly omits females. The purpose of this study was to develop a method to induce diabetes in female mice, and to determine if retinas of diabetic female mice develop molecular changes and histopathological abnormalities comparable to those which develop in male diabetic mice.

Successful induction of diabetes in mice demonstrates no gender difference in development of early diabetic retinopathy.

Previous studies indicate that leukocytes, notably neutrophils, play a causal role in the capillary degeneration observed in diabetic retinopathy (DR), however, the mechanism by which they cause such degeneration is unknown. Neutrophil elastase (NE) is a protease released by neutrophils which participates in a variety of inflammatory diseases. In the present work, we investigated the potential involvement of NE in the development of early DR.

Neutrophil-Derived Proteases Contribute to the Pathogenesis of Early Diabetic Retinopathy.

Targeted drug delivery to disease-associated activated neutrophils can provide novel therapeutic opportunities while avoiding systemic effects on immune functions. We created a nanomedicine platform that uniquely utilizes an α-antitrypsin-derived peptide to confer binding specificity to neutrophil elastase on activated neutrophils. Surface decoration with this peptide enabled specific anchorage of nanoparticles to activated neutrophils and platelet-neutrophil aggregates, in vitro and in vivo. Nanoparticle delivery of a model drug, hydroxychloroquine, demonstrated significant reduction of neutrophil activities in vitro and a therapeutic effect on murine venous thrombosis in vivo. This innovative approach of cell-specific and activation-state-specific targeting can be applied to several neutrophil-driven pathologies.

Nanomedicine platform for targeting activated neutrophils and neutrophil-platelet complexes using an α-antitrypsin-derived peptide motif.

Induction of intercellular adhesion molecule-1 (ICAM-1) has been implicated in the development of macrovascular and microvascular diseases such as diabetic retinopathy. Lesions of diabetic retinopathy are unique to the retina but the reason for this is unclear, as all tissues are exposed to the same hyperglycaemic insult. We tested whether diabetes induces ICAM-1 on the luminal surface of endothelial cells to a greater extent in the retina than in other tissues and the role of vision itself in that induction.

ICAM-1 on the luminal surface of endothelial cells is induced to a greater extent in mouse retina than in other tissues in diabetes.

Accumulating evidence suggests that leucocytes play a critical role in diabetes-induced vascular lesions and other abnormalities that characterise the early stages of diabetic retinopathy. However, the role of monocytes has yet to be fully investigated; therefore, we used Ccr2 mice to study the role of CCR2 inflammatory monocytes in the pathogenesis of diabetes-induced degeneration of retinal capillaries.

CCR2-positive monocytes contribute to the pathogenesis of early diabetic retinopathy in mice.

Chronic, progressive retinal diseases, such as age-related macular degeneration (AMD), diabetic retinopathy, and retinitis pigmentosa, arise from genetic and environmental perturbations of cellular and tissue homeostasis. These disruptions accumulate with repeated exposures to stress over time, leading to progressive visual impairment and, in many cases, legal blindness. Despite decades of research, therapeutic options for the millions of patients suffering from these disorders remain severely limited, especially for treating earlier stages of pathogenesis when the opportunity to preserve the retinal structure and visual function is greatest. To address this urgent, unmet medical need, we employed a systems pharmacology platform for therapeutic development. Through integrative single-cell transcriptomics, proteomics, and phosphoproteomics, we identified universal molecular mechanisms across distinct models of age-related and inherited retinal degenerations, characterized by impaired physiological resilience to stress. Here, we report that selective, targeted pharmacological inhibition of cyclic nucleotide phosphodiesterases (PDEs), which serve as critical regulatory nodes that modulate intracellular second messenger signaling pathways, stabilized the transcriptome, proteome, and phosphoproteome through downstream activation of protective mechanisms coupled with synergistic inhibition of degenerative processes. This therapeutic intervention enhanced resilience to acute and chronic forms of stress in the degenerating retina, thus preserving tissue structure and function across various models of age-related and inherited retinal disease. Taken together, these findings exemplify a systems pharmacology approach to drug discovery and development, revealing a new class of therapeutics with potential clinical utility in the treatment or prevention of the most common causes of blindness.

Article	Year
Neutrophil elastase contributes to the pathological vascular permeability characteristic of diabetic retinopathy. Diabetologia\| PubMed ID: 31612267	2019
Successful induction of diabetes in mice demonstrates no gender difference in development of early diabetic retinopathy. PloS one\| PubMed ID: 32941450	2020
Neutrophil-Derived Proteases Contribute to the Pathogenesis of Early Diabetic Retinopathy. Investigative ophthalmology & visual science\| PubMed ID: 34643662	2021
Nanomedicine platform for targeting activated neutrophils and neutrophil-platelet complexes using an α-antitrypsin-derived peptide motif. Nature nanotechnology\| PubMed ID: 35851383	2022
ICAM-1 on the luminal surface of endothelial cells is induced to a greater extent in mouse retina than in other tissues in diabetes. Diabetologia\| PubMed ID: 35852587	2022
CCR2-positive monocytes contribute to the pathogenesis of early diabetic retinopathy in mice. Diabetologia\| PubMed ID: 36698021	2023
Stress resilience-enhancing drugs preserve tissue structure and function in degenerating retina via phosphodiesterase inhibition. Proceedings of the National Academy of Sciences of the United States of America\| PubMed ID: 37126699	2023

Emma M. Lessieur

Biography

JoVE Journal Publications

Other Publications