Browsing by Subject "endothelial cells"

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    Angiopoietin-1 is required for Schlemm's canal development in mice and humans.
    (The Journal of clinical investigation, 2017-12) Thomson, Benjamin R; Souma, Tomokazu; Tompson, Stuart W; Onay, Tuncer; Kizhatil, Krishnakumar; Siggs, Owen M; Feng, Liang; Whisenhunt, Kristina N; Yanovitch, Tammy L; Kalaydjieva, Luba; Azmanov, Dimitar N; Finzi, Simone; Tanna, Christine E; Hewitt, Alex W; Mackey, David A; Bradfield, Yasmin S; Souzeau, Emmanuelle; Javadiyan, Shari; Wiggs, Janey L; Pasutto, Francesca; Liu, Xiaorong; John, Simon Wm; Craig, Jamie E; Jin, Jing; Young, Terri L; Quaggin, Susan E
    Primary congenital glaucoma (PCG) is a leading cause of blindness in children worldwide and is caused by developmental defects in 2 aqueous humor outflow structures, Schlemm's canal (SC) and the trabecular meshwork. We previously identified loss-of-function mutations in the angiopoietin (ANGPT) receptor TEK in families with PCG and showed that ANGPT/TEK signaling is essential for SC development. Here, we describe roles for the major ANGPT ligands in the development of the aqueous outflow pathway. We determined that ANGPT1 is essential for SC development, and that Angpt1-knockout mice form a severely hypomorphic canal with elevated intraocular pressure. By contrast, ANGPT2 was dispensable, although mice deficient in both Angpt1 and Angpt2 completely lacked SC, indicating that ANGPT2 compensates for the loss of ANGPT1. In addition, we identified 3 human subjects with rare ANGPT1 variants within an international cohort of 284 PCG patients. Loss of function in 2 of the 3 patient alleles was observed by functional analysis of ANGPT1 variants in a combined in silico, in vitro, and in vivo approach, supporting a causative role for ANGPT1 in disease. By linking ANGPT1 with PCG, these results highlight the importance of ANGPT/TEK signaling in glaucoma pathogenesis and identify a candidate target for therapeutic development.
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    Elevated PTH induces endothelial to chondrogenic transition in aortic endothelial cells.
    (Am J Physiol Renal Physiol, 2016-08-31) Wu, Min; Zhang, Jian-Dong; Tang, Ri-Ning; Crowley, Steven D; Liu, Hong; Lv, Lin-Li; Ma, Kun-Ling; Liu, Bi-Cheng
    Previous studies have shown that increased parathyroid hormone (PTH) due to secondary hyperparathyroidism in chronic kidney disease accelerates the arteriosclerotic fibrosis and calcification. Although the underlying mechanisms remain largely unknown, endothelial cells (ECs) have recently been demonstrated to participate in calcification in part by providing chondrogenic cells via the endothelial-to-mesenchymal transition (EndMT). Therefore, this study aimed to investigate whether elevated PTH could induce endothelial to chondrogenic transition in aortic ECs and to determine the possible underlying signaling pathway. We found that treatment of ECs with PTH significantly upregulated the expression of EndMT-related markers. Accordingly, ECs treated with PTH exhibited chondrogenic potential. In vivo, a lineage tracing model subjected mice with endothelial-specific GFP fluorescence to chronic PTH infusion showed a marked increase in the aortic expression of chondrocyte markers, and confocal microscopy revealed the endothelial origin of cells expressing chondrocyte markers in the aorta after PTH infusion. Furthermore, this in vitro study showed that PTH enhanced the nuclear localization of β-catenin in ECs, whereas, β-catenin siRNA or DKK1, an inhibitor of β-catenin nuclear translocation, attenuated the upregulation of EndMT-associated and chondrogenic markers induced by PTH. In summary, our study demonstrated that elevated PTH could induce the transition of ECs to chondrogenic cells via EndMT, possibly mediated by the nuclear translocation of β-catenin.
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    Inhalation of an RNA aptamer that selectively binds extracellular histones protects from acute lung injury.
    (Molecular therapy. Nucleic acids, 2023-03) Lei, Beilei; Wang, Chaojian; Snow, Kamie; Graton, Murilo E; Tighe, Robert M; Fager, Ammon M; Hoffman, Maureane R; Giangrande, Paloma H; Miller, Francis J
    Acute lung injury (ALI) is a syndrome of acute inflammation, barrier disruption, and hypoxemic respiratory failure associated with high morbidity and mortality. Diverse conditions lead to ALI, including inhalation of toxic substances, aspiration of gastric contents, infection, and trauma. A shared mechanism of acute lung injury is cellular toxicity from damage-associated molecular patterns (DAMPs), including extracellular histones. We recently described the selection and efficacy of a histone-binding RNA aptamer (HBA7). The current study aimed to identify the effects of extracellular histones in the lung and determine if HBA7 protected mice from ALI. Histone proteins decreased metabolic activity, induced apoptosis, promoted proinflammatory cytokine production, and caused endothelial dysfunction and platelet activation in vitro. HBA7 prevented these effects. The oropharyngeal aspiration of histone proteins increased neutrophil and albumin levels in bronchoalveolar lavage fluid (BALF) and precipitated neutrophil infiltration, interstitial edema, and barrier disruption in alveoli in mice. Similarly, inhaling wood smoke particulate matter, as a clinically relevant model, increased lung inflammation and alveolar permeability. Treatment by HBA7 alleviated lung injury in both models of ALI. These findings demonstrate the pulmonary delivery of HBA7 as a nucleic acid-based therapeutic for ALI.