Vascular biology
Abstract
Elevated Angiopoietin-2 is associated with diverse inflammatory conditions including sepsis, a leading global cause of mortality. During inflammation, Angiopoietin-2 antagonizes the endothelium-enriched receptor Tie2 to destabilize the vasculature. In other contexts, Angiopoietin-2 stimulates Tie2. The basis for context-dependent antagonism remains incompletely understood. Here we show that inflammation-induced proteolytic cleavage of Angiopoietin-2 converts this ligand from Tie2 agonist to antagonist. Conditioned media from stimulated macrophages induced endothelial Angiopoietin-2 secretion. Unexpectedly, this was associated with reduction of the 75 kDa full-length protein and appearance of new 25 and 50 kDa C-terminal fragments. Peptide sequencing proposed cathepsin K as a candidate protease. Cathepsin K was necessary and sufficient to cleave Angiopoietin-2. Recombinant 25 and 50 kDa Angiopoietin-2 fragments (cANGPT225, cANGPT250) bound and antagonized Tie2. Cathepsin K inhibition with the Phase-3 small molecule inhibitor odanacatib improved survival in distinct murine sepsis models. Full-length Angiopoietin-2 enhanced survival in endotoxemic mice administered odanacatib and, conversely, increased mortality in the drug’s absence. Odanacatib’s benefit was reversed by heterologous cANGPT225. Septic humans accumulated circulating Angiopoietin-2 fragments, which were associated with adverse outcomes. These results identify cathepsin K as a candidate marker of sepsis and a proteolytic mechanism for the conversion of Angiopoietin-2 from Tie2 agonist to antagonist with therapeutic implications for inflammatory conditions associated with Angiopoietin-2 induction.
Authors
Takashi Suzuki, Erik Loyde, Sara Chen, Valerie Etzrodt, Temitayo O. Idowu, Amanda J. Clark, Marie Christelle Saade, Brenda Mendoza Flores, Shulin Lu, Gabriel Birrane, Vamsidhara Vemireddy, Benjamin Seeliger, Sascha David, Samir M. Parikh
An endothelial SOX18-mevalonate pathway axis enables repurposing of statins for infantile hemangioma
Abstract
Infantile hemangioma (IH) is the most common tumor in children and a paradigm for pathological vasculogenesis, angiogenesis, and regression. Propranolol, the mainstay treatment, inhibits IH vessel formation via a β-adrenergic receptor independent off-target effect of its R(+) enantiomer on the endothelial SRY box transcription factor 18 (SOX18). Transcriptomic profiling of patient-derived hemangioma stem cells (HemSC) uncovered the mevalonate pathway (MVP) as a target of R(+) propranolol. Loss and gain of function of SOX18 confirmed it is both necessary and sufficient for R(+) propranolol suppression of the MVP, including regulation of sterol regulatory element binding protein 2 (SREBP2) and the rate-limiting enzyme HMG-CoA reductase (HMGCR). AThe biological relevance of the endothelial SOX18-MVP axis in IH patient tissue was demonstrated by nuclear co-localization of SOX18 and SREBP2. Functional validation in a preclinical IH xenograft model revealed that statins – competitive inhibitors of HMGCR – efficiently suppress IH vessel formation. We propose an novel endothelial SOX18-MVP-axis as a central regulator of IH pathogenesis and suggest statin repurposing to treat IH. The pleiotropic effects of R(+) propranolol and statins along the SOX18-MVP axis to disable an endothelial-specific program may have therapeutic implications for other vascular disease entities involving pathological vasculogenesis and angiogenesis.
Authors
Annegret Holm, Matthew S. Graus, Jill Wylie-Sears, Jerry Wei Heng Tan, Maya Alvarez-Harmon, Luke Borgelt, Sana Nasim, Long Chung, Ashish Jain, Mingwei Sun, Liang Sun, Pascal Brouillard, Ramrada Lekwuttikarn, Yanfei Qi, Joyce Teng, Miikka Vikkula, Harry Kozakewich, John B. Mulliken, Mathias Francois, Joyce Bischoff
Abstract
Polymorphisms in Nos3 increases risk for glaucoma, the leading cause of irreversible blindness worldwide. A key modifiable risk factor for glaucoma is intraocular pressure (IOP), which is regulated by nitric oxide (NO), a product of nitric oxide synthase-3 (Nos3) in Schlemm’s canal of the conventional outflow pathway. We studied the effects of a conditional, endothelial-specific postnatal deletion of Nos3 (Endo-SclCre-ERT;Nos3flox/flox) on tissues of the outflow pathway. We observed that Cre-ERT expression spontaneously and gradually increased with time in vascular endothelia including Schlemm’s canal, beginning at P10, with complete Nos3 deletion occurring around P90. Unlike the reduced outflow resistance in global Nos3 knockout mice, outflow resistance and IOP in Endo-SclCre-ERT;Nos3flox/flox mice were normal. Coinciding with Nos3 deletion, we observed recruitment of macrophages to, and induction of both ELAM-1 and NOS2 expression by endothelia in the distal portion of the outflow pathway, which increased vessel diameter. These adjustments reduced outflow resistance to maintain IOP in these Endo-SclCre-ERT;Nos3flox/flox mice. Selective inhibition of iNOS by 1400W resulted in narrowing of distal vessels and IOP elevation. Together, results emphasize the pliability of the outflow system, the importance of NO signaling in IOP control and implicates an important role for macrophages in IOP homeostasis.
Authors
Ruth A. Kelly, Megan S. Kuhn, Ester Reina-Torres, Revathi Balasubramanian, Kristin M. Perkumas, Guorong Li, Takamune Takahashi, Simon W.M. John, Michael H. Elliott, Darryl R. Overby, W. Daniel Stamer
Abstract
The osteogenic environment promotes vascular calcium phosphate deposition and aggregation of unfolded and misfolded proteins, resulting in endoplasmic reticulum (ER) stress in chronic renal disease (CKD). Controlling ER stress through genetic intervention is a promising approach for treating vascular calcification. In this study, we demonstrated a positive correlation between ER stress-induced tribble 3 (TRIB3) expression and progression of vascular calcification in human and rodent CKD. Increased TRIB3 expression promoted vascular smooth muscle cell (VSMC) calcification by interacting with the C2 domain of the E3 ubiquitin-protein ligase Smurf1, facilitating its K48-related self-ubiquitination at Lys381 and Lys383 and subsequent dissociation from the plasma membrane and nuclei. This degeneration of Smurf1 accelerated the stabilization of the osteogenic transcription factors RUNX Family Transcription Factor 2 (Runx2) and SMAD Family Member 1 (Smad1). C/EBP homologous protein and activating transcription factor 4 are upstream transcription factors of TRIB3 in an osteogenic environment. Genetic knockout of TRIB3 or rescue of Smurf1 ameliorated VSMC and vascular calcification by stabilizing Smurf1 and enhancing the degradation of Runx2 and Smad1. Our findings shed light on the vital role of TRIB3 as a scaffold in ER stress and vascular calcification and offer a potential therapeutic option for chronic renal disease.
Authors
Yihui Li, Chang Ma, Yanan Sheng, Shanying Huang, Huaibing Sun, Yun Ti, Zhihao Wang, Feng Wang, Fangfang Chen, Chen Li, Haipeng Guo, Mengxiong Tang, Fangqiang Song, Hao Wang, Ming Zhong
Abstract
Translational control shapes the proteome and is particularly important in regulating gene expression under stress. A key source of endothelial stress is treatment with tyrosine kinase inhibitors (TKIs), which lowers cancer mortality but increases cardiovascular mortality. Using a human induced pluripotent stem cell–derived endothelial cell (hiPSC-EC) model of sunitinib-induced vascular dysfunction combined with ribosome profiling, we assessed the role of translational control in hiPSC-ECs in response to stress. We identified staphylococcal nuclease and tudor domain–containing protein 1 (SND1) as a sunitinib-dependent translationally repressed gene. SND1 translational repression was mediated by the mTORC1/4E-BP1 pathway. SND1 inhibition led to endothelial dysfunction, whereas SND1 OE protected against sunitinib-induced endothelial dysfunction. Mechanistically, SND1 transcriptionally regulated UBE2N, an E2-conjugating enzyme that mediates K63-linked ubiquitination. UBE2N along with the E3 ligases RNF8 and RNF168 regulated the DNA damage repair response pathway to mitigate the deleterious effects of sunitinib. In silico analysis of FDA-approved drugs led to the identification of an ACE inhibitor, ramipril, that protected against sunitinib-induced vascular dysfunction in vitro and in vivo, all while preserving the efficacy of cancer therapy. Our study established a central role for translational control of SND1 in sunitinib-induced endothelial dysfunction that could potentially be therapeutically targeted to reduce sunitinib-induced vascular toxicity.
Authors
Zhenbo Han, Gege Yan, Jordan Jousma, Sarath Babu Nukala, Mehdi Amiri, Stephen Kiniry, Negar Tabatabaei, Youjeong Kwon, Sen Zhang, Jalees Rehman, Sandra Pinho, Sang-Bing Ong, Pavel V. Baranov, Soroush Tahmasebi, Sang-Ging Ong
Abstract
Hypoxia is a major cause of pulmonary hypertension (PH) worldwide, and it is likely that interstitial pulmonary macrophages contribute to this vascular pathology. We observed in hypoxia-exposed mice an increase in resident interstitial macrophages, which expanded through proliferation and expressed the monocyte recruitment ligand CCL2. We also observed an increase in CCR2+ macrophages through recruitment, which express the protein thrombospondin-1 that functionally activates TGF-beta to cause vascular disease. Blockade of monocyte recruitment with either CCL2 neutralizing antibody treatment or CCR2 deficiency in the bone marrow compartment suppressed hypoxic PH. These data were supported by analysis of plasma samples from humans who travelled from low (225m) to high (3500m) elevation, revealing an increase in thrombospondin-1 and TGF-beta expression following ascent, which was blocked by dexamethasone prophylaxis. In the hypoxic mouse model, dexamethasone prophylaxis recapitulated these findings by mechanistically suppressing CCL2 expression and CCR2+ monocyte recruitment. These data suggest a pathologic cross-talk between two discrete interstitial macrophage populations, which can be therapeutically targeted.
Authors
Rahul Kumar, Kevin Nolan, Biruk Kassa, Neha Chanana, Tsering Palmo, Kavita Sharma, Kanika Singh, Claudia Mickael, Dara Fonseca Balladares, Julia Nilsson, Amit Prabhakar, Aastha Mishra, Michael H. Lee, Linda Sanders, Sushil Kumar, Ari B. Molofsky, Kurt R. Stenmark, Dean Sheppard, Rubin M. Tuder, Mohit D. Gupta, Tashi Thinlas, Qadar Pasha, Brian B. Graham
Abstract
The pathogenesis of thoracic aortic aneurysm (TAA) in Marfan syndrome (MFS) is generally attributed to vascular smooth muscle cell (VSMC) pathologies. However, the role of immune cell–mediated inflammation remains elusive. Single-cell RNA sequencing identified a subset of CX3CR1+ macrophages mainly located in the intima in the aortic roots and ascending aortas of Fbn1C1041G/+ mice, further validated in MFS patients. Specific elimination of CX3CR1+ cells by diphtheria toxin in Cx3cr1-CreERT2iDTRF/+Fbn1C1041G/+ mice efficiently ameliorated TAA progression. Administering the monoclonal antibodies to respectively neutralize TNF-α and IGF1 produced by CX3CR1+ cells from MFS patients greatly suppressed the cocultured MFS patient–specific induced pluripotent stem cell–derived VSMC inflammation. BM transplantation and parabiosis revealed that CX3CR1+ macrophages are mainly originated from BM-derived monocytes. Targeting TNF-α and IGF1 in CX3CR1+ macrophages via shRNA lentivirus transduction in BM cells efficiently suppressed TAA development in BM-transplanted Fbn1C1041G/+ mice. Application of the CCR2 antagonist RS504393 to inhibit monocyte infiltration markedly reduced the accumulation of CX3CR1+ macrophages and subsequently alleviated TAA progression in Fbn1C1041G/+ mice. In summary, CX3CR1+ macrophages mainly located in aortic intima mediate TAA formation by paracrinally causing VSMC inflammation, and targeting them offers a potential antiinflammatory therapeutic strategy for MFS-related TAA.
Authors
Jiaqi Huang, Hao Liu, Zhujiang Liu, Zhenting Wang, Hanshi Xu, Zhuofan Li, Shan Huang, Xueyuan Yang, Yicong Shen, Fang Yu, Yulin Li, Junming Zhu, Wei Li, Li Wang, Wei Kong, Yi Fu
Abstract
Ischemic stroke is a major cause of adult disability. Early treatment with thrombolytics and/or thrombectomy can significantly improve outcomes; however, following these acute interventions, treatment is limited to rehabilitation therapies. Thus, the identification of therapeutic strategies that can help restore brain function in the post-acute phase remains a major challenge. Here we report that genetic or pharmacologic inhibition of the PDGF-CC/PDGFRα pathway, which has previously been implicated in stroke pathology, significantly reduced myofibroblast expansion in the border of the fibrotic scar and improved outcome in a sensory-motor integration test after experimental ischemic stroke. This was supported by gene expression analyses of cerebrovascular fragments, showing upregulation of pro-fibrotic/pro-inflammatory genes, including genes of the TGFβ pathway, after ischemic stroke or intracerebroventricular injection of active PDGF-CC. Further, longitudinal intravital two-photon imaging revealed that inhibition of PDGFRα dampened the bi-phasic pattern of stroke-induced vascular leakage and enhanced vascular perfusion in the ischemic lesion. Importantly, we found efficacy of PDGFRα inhibition on functional recovery when initiated 24 hours after ischemic stroke. Our data implicate the PDGF-CC/PDGFRα pathway as a crucial mediator modulating post-stroke pathology and suggest a post-acute treatment opportunity for ischemic stroke patients targeting myofibroblast expansion to foster long-term CNS repair.
Authors
Jil Protzmann, Manuel Zeitelhofer, Christina Stefanitsch, Daniel Torrente, Milena Z. Adzemovic, Kirils Matjunins, Stella J.I. Randel, Sebastian A. Lewandowski, Lars Muhl, Ulf Eriksson, Ingrid Nilsson, Enming J. Su, Daniel A. Lawrence, Linda Fredriksson
Abstract
Disruptions of blood pressure (BP) circadian variation are closely associated with an increased risk of cardiovascular disease (CVD). Thus, gaining insights into the molecular mechanisms of BP circadian variation is essential for comprehending BP regulation. Human genetic analyses suggest that PR domain-containing protein 16 (PRDM16), a transcription factor highly expressed in vascular smooth muscle cells (VSMC), is significantly associated with BP-related traits. However, the roles of PRDM16 in BP regulation are largely unknown. Here, we demonstrate that BP in VSMC-specific Prdm16 knockout (Prdm16SMKO) mice was significantly lower than that in control mice during the active period, resulting in aberrant BP circadian variation. Mesenteric artery rings from Prdm16SMKO mice showed reduced response to phenylephrine. Mechanistically, we identified adrenergic receptor alpha 1d (Adra1d) as a transcriptional target of PRDM16. Notably, PRDM16 exhibits a remarkable circadian expression pattern and regulates the expression of clock genes, particularly Npas2, which is crucial for BP circadian variation regulation. Consequently, PRDM16 deficiency in VSMC causes disrupted BP circadian variation through reduced response to adrenergic signaling and clock gene regulation. Our findings offer substantial insights into the intricate molecular pathways that govern circadian fluctuations in BP.
Authors
Zhenguo Wang, Wenjuan Mu, Juan Zhong, Ruiyan Xu, Yaozhong Liu, Guizhen Zhao, Yanhong Guo, Jifeng Zhang, Ida Surakka, Y. Eugene Chen, Lin Chang
Abstract
Clonal hematopoiesis (CH) increases inflammasome-linked atherosclerosis but the mechanisms by which CH mutant cells transmit inflammatory signals to non-mutant cells are largely unknown. To address this question we transplanted 1.5% Jak2VF bone marrow (BM) cells with 98.5% WT BM cells into hyperlipidemic Ldlr–/– mice. Low allele burden (LAB) mice showed accelerated atherosclerosis with increased features of plaque instability, decreased levels of macrophage phagocytic receptors MERTK and TREM2, and increased neutrophil extracellular traps (NETs). These changes were reversed when Jak2VF BM was transplanted with Il1r1–/– BM. LAB mice with non-cleavable MERTK in WT BM showed improvements in necrotic core and fibrous cap formation and reduced NETs. An agonistic TREM2 antibody (4D9) markedly increased fibrous caps in both control and LAB mice eliminating the difference between groups. Mechanistically, 4D9 increased TREM2+PDGFB+ macrophages and PDGF receptor-α positive fibroblast-like cells in the cap region. TREM2 and PDGFB mRNA levels were positively correlated in human carotid plaques and co-expressed in macrophages. In summary, low frequency Jak2VF mutations promote atherosclerosis via IL-1 signaling from Jak2VF to WT macrophages and neutrophils promoting cleavage of phagocytic receptors and features of plaque instability. Therapeutic approaches that stabilize MERTK or TREM2 could promote plaque stabilization especially in CH- and inflammasome-driven atherosclerosis.
Authors
Wenli Liu, Brian D. Hardaway, Eunyoung Kim, Jessica Pauli, Justus Leonard Wettich, Mustafa Yalcinkaya, Cheng-Chieh Hsu, Tong Xiao, Muredach P. Reilly, Ira Tabas, Lars Maegdefessel, Kai Schlepckow, Haass Christian, Nan Wang, Alan R. Tall
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)