Gαi1/3 mediation of Akt-mTOR activation is important for RSPO3-induced angiogenesis

Xu, Gang; Qi, Lijuan; Zhang, Meiqing; Xue-yun, LI; Chai, Jin-long; Zhang, Zhiqing; Chen, Xia; Wang, Qian; Li, Keran; Cao, Cong

doi:10.1093/procel/pwac035

Cited by 13 publications

(83 citation statements)

References 15 publications

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“…Wild type (WT) MEFs and Gαi1 plus Gα3 double KO (DKO) MEFs were used to investigate Gαi proteins' involvement in SCF-induced signaling, as reported previously 26 - 28 , 30 , 31 , 33 , 34 . These cells were treated with SCF (at 10, 50, or 100 ng/mL).…”

Section: Resultsmentioning

confidence: 99%

“…To silence Gαi1 and Gαi3, the Gαi1 (murine) shRNA-packed lentiviral particles and the Gαi3 (murine) shRNA-packed lentiviral particles, were constructed as reported previously 26 - 28 , 30 , 34 . These were co-transfected into WT MEFs.…”

Section: Resultsmentioning

confidence: 99%

“…Following a previously described protocol 23 , 34 , AAV5-TIE1-Gαi1 shRNA and AAV5-TIE1-Gαi3 shRNA were intravitreously injected to C57B/6 mice 34 . This led to endothelial knockdown of Gαi1/3 (Gαi1/3-eKD 34 ) as the viral construct contained the binding sequence for the endothelial-specific promoter, TIE1 23 , 34 . The mRNA and protein expressions of Gαi1 and Gαi3 decreased robustly in the retinal tissues of the Gαi1/3-eKD mice (Figures 6 A and B).…”

Section: Resultsmentioning

confidence: 99%

“…Phosphoenolpyruvate carboxykinase 1's (PCK1) association with Gαi3's transcription factor, GATA binding protein 4 (GATA4) increases the transcription and expression of Gαi3 in endothelial cells and promotes angiogenesis 23 . In response to R-spondin3 (RSPO3) stimulation, Gαi1/3 associated with LGR4 (RSPO3 receptor) and the adaptor protein, Gab1, thus transducing downstream Akt-mTOR signaling and promoting angiogenesis 34 . Herein, we evaluate the possible role and underlying mechanism of Gαi1/3 action in SCF/c-Kit-activated signaling and angiogenesis.…”

Section: Introductionmentioning

confidence: 99%

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SCF/c-Kit-activated signaling and angiogenesis require Gαi1 and Gαi3

Shan¹,

Jiang²,

Zhao³

et al. 2023

Int. J. Biol. Sci.

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The stem cell factor (SCF) binds to c-Kit in endothelial cells, thus activating downstream signaling and angiogenesis. Herein, we examined the role of G protein subunit alpha inhibitory (Gαi) proteins in this process. In MEFs and HUVECs, Gαi1/3 was associated with SCF-activated c-Kit, promoting c-Kit endocytosis, and binding of key adaptor proteins, subsequently transducing downstream signaling. SCF-induced Akt-mTOR and Erk activation was robustly attenuated by Gαi1/3 silencing or knockout (KO), or due to dominant negative mutations but was strengthened substantially following ectopic overexpression of Gαi1/3. SCF-induced HUVEC proliferation, migration, and capillary tube formation were suppressed after Gαi1/3 silencing or KO, or due to dominant negative mutations. In vivo , endothelial knockdown of Gαi1/3 by intravitreous injection of endothelial-specific shRNA adeno-associated virus (AAV) potently reduced SCF-induced signaling and retinal angiogenesis in mice. Moreover, mRNA and protein expressions of SCF increased significantly in the retinal tissues of streptozotocin-induced diabetic retinopathy (DR) mice. SCF silencing, through intravitreous injection of SCF shRNA AAV, inhibited pathological retinal angiogenesis and degeneration of retinal ganglion cells in DR mice. Finally, the expression of SCF and c-Kit increased in proliferative retinal tissues of human patients with proliferative DR. Taken together, Gαi1/3 mediate SCF/c-Kit-activated signaling and angiogenesis.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

SCF/c-Kit-activated signaling and angiogenesis require Gαi1 and Gαi3

Shan¹,

Jiang²,

Zhao³

et al. 2023

Int. J. Biol. Sci.

View full text Add to dashboard Cite

show abstract

“…Gαi1/3 association with multiple RTKs (and non-RTK receptors) mediates Akt-mTOR cascade activation 15 , 16 , 18 , 19 , 21 , 31 , 39 . In P1 glioma cells, Gαi2 shRNA or KO however failed to significantly inhibit phosphorylation of Akt and S6K1 (Figure 6A ).…”

Section: Resultsmentioning

confidence: 99%

G protein inhibitory α subunit 2 is a molecular oncotarget of human glioma

Wang¹,

Liu²,

Wu³

et al. 2023

Int. J. Biol. Sci.

Self Cite

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Identification of novel therapeutic oncotargets for human glioma is extremely important. Here we tested expression, potential functions and underlying mechanisms of G protein inhibitory α subunit 2 (Gαi2) in glioma. Bioinformatics analyses revealed that Gαi2 expression is significantly elevated in human glioma, correlating with poor patients' survival, higher tumor grade and wild-type IDH status. Moreover, increased Gαi2 expression was also in local glioma tissues and different glioma cells. In primary and immortalized (A172) glioma cells, Gαi2 shRNA or knockout (KO, by Cas9-sgRNA) potently suppressed viability, proliferation, and mobility, and induced apoptosis. Ectopic Gαi2 overexpression, using a lentiviral construct, further augmented malignant behaviors in glioma cells. p65 phosphorylation, NFκB activity and expression of NFκB pathway genes were decreased in Gαi2-depleted primary glioma cells, but increased following Gαi2 overexpression. There was an increased binding between Gαi2 promoter and Sp1 (specificity protein 1) transcription factor in glioma tissues and different glioma cells. In primary glioma cells Gαi2 expression was significantly reduced following Sp1 silencing, KO or inhibition. In vivo studies revealed that Gαi2 shRNA-expressing AAV intratumoral injection hindered growth of subcutaneous glioma xenografts in nude mice. Moreover, Gαi2 KO inhibited intracranial glioma xenograft in nude mice. Gαi2 depletion, NFκB inhibition and apoptosis induction were observed in subcutaneous and intracranial glioma xenografts with Gαi2 depletion. Together, overexpressed Gαi2 is important for glioma cell growth possibly by promoting NFκB cascade activation.

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The mitochondrial protein TIMM44 is required for angiogenesis in vitro and in vivo

Liu

Cai

et al. 2023

Cell Death Dis

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The mitochondrial integrity and function in endothelial cells are essential for angiogenesis. TIMM44 (translocase of inner mitochondrial membrane 44) is essential for integrity and function of mitochondria. Here we explored the potential function and the possible mechanisms of TIMM44 in angiogenesis. In HUVECs, human retinal microvascular endothelial cells and hCMEC/D3 brain endothelial cells, silence of TIMM44 by targeted shRNA largely inhibited cell proliferation, migration and in vitro capillary tube formation. TIMM44 silencing disrupted mitochondrial functions in endothelial cells, causing mitochondrial protein input arrest, ATP reduction, ROS production, and mitochondrial depolarization, and leading to apoptosis activation. TIMM44 knockout, by Cas9-sgRNA strategy, also disrupted mitochondrial functions and inhibited endothelial cell proliferation, migration and in vitro capillary tube formation. Moreover, treatment with MB-10 (“MitoBloCK-10”), a TIMM44 blocker, similarly induced mitochondrial dysfunction and suppressed angiogenic activity in endothelial cells. Contrarily, ectopic overexpression of TIMM44 increased ATP contents and augmented endothelial cell proliferation, migration and in vitro capillary tube formation. In adult mouse retinas, endothelial knockdown of TIMM44, by intravitreous injection of endothelial specific TIMM44 shRNA adenovirus, inhibited retinal angiogenesis, causing vascular leakage, acellular capillary growth, and retinal ganglion cells degeneration. Significant oxidative stress was detected in TIMM44-silenced retinal tissues. Moreover, intravitreous injection of MB-10 similarly induced oxidative injury and inhibited retinal angiogenesis in vivo. Together, the mitochondrial protein TIMM44 is important for angiogenesis in vitro and in vivo, representing as a novel and promising therapeutic target of diseases with abnormal angiogenesis.

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Gαi1/3 mediation of Akt-mTOR activation is important for RSPO3-induced angiogenesis

Cited by 13 publications

References 15 publications

SCF/c-Kit-activated signaling and angiogenesis require Gαi1 and Gαi3

SCF/c-Kit-activated signaling and angiogenesis require Gαi1 and Gαi3

G protein inhibitory α subunit 2 is a molecular oncotarget of human glioma

The mitochondrial protein TIMM44 is required for angiogenesis in vitro and in vivo

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