Three-Dimensional Visualization of Hypoxia-Induced Pulmonary Vascular Remodeling in Mice

Fujiwara, Takayuki; Takeda, Norifumi; Hara, Hironori; Ishii, Satoshi; Numata, Genri; Tokiwa, Hiroyuki; Maemura, Sonoko; Suzuki, Takaaki; Kubota, Yoshiaki; Seo, Kinya; Sakata, Asuka; Nomura, Seitaro; Hatano, Masaru; Ueda, Kazutaka; Harada, Mutsuo; Toko, Haruhiro; Takimoto, Eiki; Akazawa, Hiroshi; Nishimura, Satoshi; Komuro, Issei

doi:10.1161/circulationaha.121.056219

Cited by 6 publications

(18 citation statements)

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“…Increased pulmonary vascular resistance and respiratory and circulatory failure result from increased wall thickness, muscle extension into normally non‐muscular arterioles, and vascular stiffening. [ 7,24 ] However, we observed that cerebral vascular remodeling was induced by hypoxia, and PRRC2B cKO enhanced the remodeling process, promoting mice adaptation to hypoxia. Therefore, we demonstrated the physiological implication of PRRC2B changes in endothelial cells (Figure 2).…”

Section: Discussionmentioning

confidence: 89%

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The Role of PRRC2B in Cerebral Vascular Remodeling Under Acute Hypoxia in Mice

Gong

et al. 2023

Advanced Science

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High altitude exposure leads to various cognitive impairments. The cerebral vasculature system plays an integral role in hypoxia‐induced cognitive defects by reducing oxygen and nutrition supply to the brain. RNA N6‐methyladenosine (m6A) is susceptible to modification and regulates gene expression in response to environmental changes, including hypoxia. However, the biological significance of m6A in endothelial cell performance under hypoxic conditions is unknown. Using m6A‐seq, RNA immunoprcipitation‐seq, and transcriptomic co‐analysis, the molecular mechanism of vascular system remodeling under acute hypoxia is investigated. A novel m6A reader protein, proline‐rich coiled‐coil 2B (PRRC2B), exists in endothelial cells. PRRC2B knockdown promoted hypoxia‐induced endothelial cell migration by regulating alternative splicing of the alpha 1 chain of collagen type XII in an m6A‐dependent manner and the decay of matrix metallopeptidase domain 14 and ADAM metallopeptidase domain 19 mRNA in an m6A‐independent manner. In addition, conditional knockout of PRRC2B in endothelial cells promotes hypoxia‐induced vascular remodeling and cerebral blood flow redistribution, thus alleviating hypoxia‐induced cognitive decline. Therefore, PRRC2B is integral in the hypoxia‐induced vascular remodeling process as a novel RNA‐binding protein. These findings provide a new potential therapeutic target for hypoxia‐induced cognitive decline.

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Section: Discussionmentioning

confidence: 89%

“…[ 6 ] Recent studies have revealed that during hypoxia stimulation, the capillaries or vessel terminals are regenerated, and the vascular system is also subjected to remodeling. [ 7 ] However, the underlying mechanism of hypoxia‐induced cerebral vascular remodeling remains unclear.…”

Section: Introductionmentioning

confidence: 99%

The Role of PRRC2B in Cerebral Vascular Remodeling Under Acute Hypoxia in Mice

Gong

et al. 2023

Advanced Science

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“…Consistent with our findings, a recent 3-dimensional EC lineage tracing revealed EC sprouting and elongation in a hypoxia-induced PH mouse model. 41 Howell et al 42 also demonstrated that chronic hypoxia in rats resulted in increased pulmonary vessel length, volume, endothelial surface area, and number of ECs by using stereological techniques combined with confocal microscopy. These findings suggest that hypoxia induces angiogenesis in the pulmonary vascular system, similar to that in the systemic circulation, to adapt to the lack of oxygen.…”

Section: Discussionmentioning

confidence: 99%

Flk1 Deficiency and Hypoxia Synergistically Promote Endothelial Dysfunction, Vascular Remodeling, and Pulmonary Hypertension

Akiyama

Sadahiro

Yamada

et al. 2023

ATVB

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BACKGROUND: The mechanisms underlying pulmonary hypertension (PH) remain largely unknown; further, why advanced vascular remodeling preferentially occurs in arterioles is yet to be answered. VEGF (vascular endothelial growth factor) regulates angiogenesis through Flk1 and Flt1 on endothelial cells (ECs), which may be related to PH pathogenesis. However, spatiotemporal expression patterns of Flk1 and Flt1 in the pulmonary vascular system and the role of endothelial Flk1 in PH development remain poorly understood. METHODS: We analyzed multiple reporter mice, including Flk1-GFP bacterial artificial chromosome transgenic (Tg), Flt1-DsRed bacterial artificial chromosome Tg, and Flk1-GFP/Flt1-DsRed double Tg mice, to determine the spatiotemporal expression of Flk1 and Flt1 in hypoxia-induced PH. We also used Cdh5 CreERT2 /Flk1 f/f /Tomato (Flk1-KO) mice to induce EC-specific Flk1 deletion and lineage tracing in chronic hypoxia. RESULTS: Flk1 was specifically expressed in the ECs of small pulmonary vessels, including arterioles. Conversely, Flt1 was more broadly expressed in the ECs of large- to small-sized vessels in adult mouse lungs. Intriguingly, Flk1 + ECs were transiently increased in hypoxia with proliferation, whereas Flt1 expression was unchanged. Flk1-KO mice did not exhibit pulmonary vascular remodeling nor PH in normoxia; however, the arteriolar ECs changed to a cuboidal shape with protrusion. In hypoxia, Flk1 deletion exacerbated EC dysfunction and reduced their number via apoptosis. Additionally, Flk1 deletion promoted medial thickening and neointimal formation in arterioles and worsened PH. Mechanistically, lineage tracing revealed that neointimal cells were derived from Flk1-KO ECs. Moreover, RNA sequencing in pulmonary ECs demonstrated that Flk1 deletion and hypoxia synergistically activated multiple pathways, including cell cycle, senescence/apoptosis, and cytokine/growth factor, concomitant with suppression of cell adhesion and angiogenesis, to promote vascular remodeling. CONCLUSIONS: Flk1 and Flt1 were differentially expressed in pulmonary ECs. Flk1 deficiency and hypoxia jointly dysregulated arteriolar ECs to promote vascular remodeling. Thus, dysfunction of Flk1 + ECs may contribute to the pathogenesis of advanced vascular remodeling in pulmonary arterioles.

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“…Recently, we have established a 3D-imaging analysis method for the visualization of murine pulmonary vasculature using clear unobstructed brain- and body-imaging cocktails and computational analysis (CUBIC) ( 11 ) combined with multiphoton microscopy. Using this technique, we have successfully generated 3D images of the whole lung at full depth and single-cell resolution in mice, which revealed the previously uncharacterized dynamic of spatial pulmonary vascular remodeling ( 12 ) not previously observed using conventional 2D histological examination. Our previous results demonstrated that Hx stimulates the proliferation of ECs and SMCs, which extends to the peripheral lung ( 12 ).…”

Section: Introductionmentioning

confidence: 98%

PGC-1α–mediated angiogenesis prevents pulmonary hypertension in mice

Fujiwara,

Takeda,

Hara

et al. 2023

JCI Insight

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Pulmonary hypertension (PH) is a life-threatening disease characterized by a progressive narrowing of pulmonary arterioles. Although VEGF is highly expressed in lung of patients with PH and in animal PH models, the involvement of angiogenesis remains elusive. To clarify the pathophysiological function of angiogenesis in PH, we compared the angiogenic response in hypoxia (Hx) and SU5416 (a VEGFR2 inhibitor) plus Hx (SuHx) mouse PH models using 3D imaging. The 3D imaging analysis revealed an angiogenic response in the lung of the Hx-PH, but not of the severer SuHx-PH model. Selective VEGFR2 inhibition with cabozantinib plus Hx in mice also suppressed angiogenic response and exacerbated Hx-PH to the same extent as SuHx. Expression of endothelial proliferator-activated receptor γ coactivator 1α (PGC-1α) increased along with angiogenesis in lung of Hx-PH but not SuHx mice. In pulmonary endothelial cell–specific Ppargc1a -KO mice, the Hx-induced angiogenesis was suppressed, and PH was exacerbated along with increased oxidative stress, cellular senescence, and DNA damage. By contrast, treatment with baicalin, a flavonoid enhancing PGC-1α activity in endothelial cells, ameliorated Hx-PH with increased Vegfa expression and angiogenesis. Pulmonary endothelial PGC-1α–mediated angiogenesis is essential for adaptive responses to Hx and might represent a potential therapeutic target for PH.

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Three-Dimensional Visualization of Hypoxia-Induced Pulmonary Vascular Remodeling in Mice

Cited by 6 publications

References 6 publications

The Role of PRRC2B in Cerebral Vascular Remodeling Under Acute Hypoxia in Mice

The Role of PRRC2B in Cerebral Vascular Remodeling Under Acute Hypoxia in Mice

Flk1 Deficiency and Hypoxia Synergistically Promote Endothelial Dysfunction, Vascular Remodeling, and Pulmonary Hypertension

PGC-1α–mediated angiogenesis prevents pulmonary hypertension in mice

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