Evidence map›Paper›PMID 42804124›Full record

ArticleCNS neuroscience & therapeutics2026

Hyperglycemia-Induced Microglial CTSS Disrupts Blood-Retinal Barrier Integrity via PAR2-Dependent Downregulation of Endothelial MFSD2A.

Chengye Xu, Hongxue Li, Qian Xu, Kangqi Zhao, Yangwen Chen, Yan Wang, Wei Zou, Binglin Kuang, Hongyu Kuang

Abstract read
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Article in CNS neuroscience & therapeutics, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

9 authors.

Chengye XuThe Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Hongxue LiThe Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Qian XuThe Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.ORCID https://orcid.org/0000-0001-8326-3188
Kangqi ZhaoThe Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Yangwen ChenThe Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Yan WangThe Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
Wei ZouAcupuncture and Moxibustion Department III, The First Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine, Harbin, China.
Binglin KuangAcupuncture and Moxibustion Department III, The First Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine, Harbin, China.
Hongyu KuangThe Department of Endocrinology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.ORCID https://orcid.org/0000-0001-6309-9798

Funding

National Natural Science Foundation of China 82370827
6 · The paper itself

Abstract

backgroundDiabetic retinopathy (DR), a leading cause of blindness in diabetes, involves dysregulated neuroimmune crosstalk. While microglial activation and endothelial dysfunction are established in DR, the molecular mechanisms linking innate immunity to blood-retinal barrier (BRB) breakdown remain elusive.

methodsWe combined single-cell RNA sequencing (scRNA-seq) of diabetic mouse retinas with in vivo models, retinal endothelial MFSD2A overexpression, and microglial Cathepsin S (CTSS) knockdown via adeno-associated virus (AAV). Human retinal microvascular endothelial cells (HRMECs) and human microglial cells (HMC3) were subjected to high-glucose conditions combined with in vitro systems (transwell co-cultures, holographic 3D tomography). Mechanistic studies employed siRNA knockdown, plasmid overexpression, exogenous CTSS supplementation, and transcytosis assays.

resultsscRNA-seq revealed diabetes-induced CTSS upregulation in retinal microglia (p = 0.0031) and MFSD2A downregulation in endothelial cells (p = 0.01). Microglial CTSS promoted M1 polarization (p < 0.001) and pro-inflammatory cytokine secretion (IL-1β and TNF-α, p < 0.05), while Ctss knockdown attenuated these effects (p < 0.05). CTSS activated endothelial PAR2, suppressing endothelial MFSD2A and enhancing caveolin-1-mediated transcytosis. Endothelial MFSD2A overexpression reduced vascular permeability independently of tight junction modulation (ZO-1, Occludin, Claudin-5, p > 0.05). Microglia-endothelial crosstalk was disrupted in diabetes, with ultrastructural alterations (cytoplasmic shrinkage, microglial amoeboid transformation) promoting cytotoxic interactions and exacerbate vascular endothelial damage.

conclusionsHyperglycemia induces retinal microglial activation and CTSS upregulation, disrupting microglia-endothelial crosstalk via the PAR2 pathway, suppressing endothelial MFSD2A expression, enhancing transcytosis, compromising iBRB integrity, and accelerating DR progression. Therapeutic strategies targeting microglial CTSS or endothelial MFSD2A represent promising avenues for preserving vision in diabetic patients.

Indexed as

Blood-Retinal BarrierEndothelial CellsHyperglycemiaMicrogliaReceptor, PAR-2AnimalsDiabetic RetinopathyDown-RegulationHumansMaleMiceMice, Inbred C57BLSymportersMfsd2a protein, mouseReceptor, PAR-2SymportersCathepsin Sdiabetic retinopathyendothelial cellsmajor facilitator superfamily domain‐containing protein 2amicroglia

Identifiers

PMID42804124
PMCPMC13618738

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.