Basic Sciences

Angiogenic Factor With G Patch and FHA Domains 1 Is a Novel Regulator of Vascular InjuryHighlights

Bisheng Zhou, Sheng Zeng, Nan Li, Liming Yu, Guang Yang, Yuyu Yang, Xinjian Zhang, Mingming Fang, Jun Xia, Yong Xu
https://doi.org/10.1161/ATVBAHA.117.308992
Arteriosclerosis, Thrombosis, and Vascular Biology. 2017;37:675-684
Originally published February 2, 2017

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Abstract

Objective—Phenotypic modulation of vascular smooth muscle cells represents a hallmark event in vascular injury. The underlying mechanism is not completely sorted out. We investigated the involvement of angiogenic factor with G patch and FHA domains 1 (Aggf1) in vascular injury focusing on the transcriptional regulation of vascular smooth muscle cell signature genes.

Approach and Results—We report here that Aggf1 expression was downregulated in several different cell models of phenotypic modulation in vitro and in the vessels after carotid artery ligation in mice. Adenovirus-mediated Aggf1 overexpression dampened vascular injury and normalized vascular smooth muscle cell signature gene expression. Mechanistically, Aggf1 interacted with myocardin and was imperative for the formation of a serum response factor–myocardin complex on gene promoters. In response to injurious stimuli, kruppel-like factor 4 was recruited to the Aggf1 promoter and enlisted histone deacetylase 11 to repress Aggf1 transcription. In accordance, depletion of kruppel-like factor 4 or histone deacetylase 11 restored Aggf1 expression and abrogated vascular smooth muscle cell phenotypic modulation. Finally, treatment of a histone deacetylase 11 inhibitor attenuated vascular injury in mice.

Conclusions—Therefore, we have unveiled a previously unrecognized role for Aggf1 in regulating vascular injury.

Introduction

Vascular injury invariably parallels profound phenotypic and functional alterations of cells in the vessels. For instance, vascular endothelial cells, in response to a host of proinflammatory stress signals, upregulate the expression of adhesion molecules on the cell surface to support a firm attachment of circulating leukocytes, a process that initiates vascular inflammation.1,2 Vascular smooth muscle cells (VSMCs), on the contrary, when challenged with injurious stimuli, switch from a contractile phenotype to a synthetic phenotype in a process now known as phenotypic modulation (PM).3 During PM, VSMCs shed the expression of contraction-related genes such as myosin heavy chain and myosin light chain kinase while gaining the ability to proliferate and migrate. VSMC PM constitutes the pathophysiological basis for neointima formation and plays a key role in the pathogenesis of a range of cardiovascular diseases.4

VSMC PM is regulated by a complex network of signaling pathways that converge on a few conserved transcription factors. Seminal work in the past decade or so has identified serum response factor (SRF) as a key sequence-specific transcription factor that drives the expression of SMC signature genes; one or more CC(A/T)6GG (also known as the CArG box) motifs are present on the promoters of SMC signature genes for SRF to recognize and bind.5 SRF-mediated transactivation of contractile genes requires the enlistment of myocardin, a cofactor that is exclusively expressed in the muscle lineage.6,7 On the contrary, many transcription factors have been shown to antagonize the activity of SRF–myocardin.8 Kruppel-like factor 4 (KLF4), for instance, is upregulated in SMCs during vascular injury and blocks the binding of SRF to the CArG box on the α-smooth muscle actin gene promoter.9 In addition, KLF4 may directly bind to and mediate the repression of myocardin gene by platelet-derived growth factor (PDGF-BB).10 Therefore, disruption of the SRF–myocardin tertiary complex on the contractile gene promoters downregulates their transcription and compels SMCs to pivot to the synthetic phenotype.

Angiogenic factor with G patch and FHA domains 1 (Aggf1) was isolated from patients with Klippel–Trenaunay syndrome and characterized as a proangiogenic protein.11 The investigations on Aggf1 have since been exclusively focused on its ability to alleviate organ/tissue ischemia12,13; little is known about its role in regulating SMC phenotype. Here, we report that Aggf1 expression is downregulated in SMCs undergoing PM, whereas Aggf1 overexpression restores the contractile phenotype of SMCs both in vitro and in vivo by stabilizing the SRF–myocardin complex. KLF4 represses Aggf1 transcription by recruiting histone deacetylase 11 (HDAC11), the depletion or inhibition of which is sufficient to block SMC PM. Thus, our report uncovers a previously unrecognized role for Aggf1 in regulating vascular injury.

Materials and Methods

An expanded Materials and Methods can be found in the online-only Data Supplement.

Results

Aggf1 Expression Is Inversely Correlated With VSMC PM

To assign a role for Aggf1 during VSMC PM, we first examined Aggf1 expression in different cellular and animal models of vascular injury. As shown in Figure 1A and 1B, mRNA and protein levels of Aggf1 were downregulated in human primary aortic smooth muscle cells (HASMCs) exposed to PDGF paralleling a reduction in the expression of SM22α, a VSMC signature gene. Likewise, we observed decreased Aggf1 expression accompanying PM in HASMCs treated with several other injurious stimuli including oxidized phospholipids (Figure I in the online-only Data Supplement), angiotensin II (Figure II in the online-only Data Supplement), and low oxygen tension (Figure II in the in the online-only Data Supplement). We also examined Aggf1 in an animal model of vascular injury. Aggf1 was downregulated in the vessels after carotid artery ligation (Figure 1C and 1D) in C57/BL6 mice. Together, these data establish an inverse correlation between Aggf1 expression and VSMC PM.

Figure 1.
Figure 1.

Angiogenic factor with G patch and FHA domains 1 (Aggf1) expression is downregulated during phenotypic modulation. A and B, human aortic smooth muscle (SM) cells were treated with platelet-derived growth factor and harvested at indicated time points. Aggf1 mRNA and protein levels were examined by quantitative polymerase chain reaction (qPCR; A) and Western (B). C and D, Carotid artery ligation-induced vascular injury was performed in Sprague–Dawley rats. Aggf1 mRNA and protein levels in vessels were examined by qPCR (C) and immunofluorescence staining (D). n=10 rats for each group. Scale bar, 50 μm. PDGF indicates platelet-derived growth factor.

Aggf1 Overexpression Overcomes PM

Next, we asked whether forced Aggf1 expression could avert PM in VSMCs in response to injurious stimuli. To this end, HASMCs were infected with adenovirus either an Aggf1 expression vector (Ad-AGGF1) or an empty vector (Ad-Vec) before being exposed to PDGF. Indeed, Ad-AGGF1 more than compensated the loss of VSMC signature genes at both 24 and 48 hours after PDGF treatment in HSMCs (Figure 2A and 2B). On the contrary, small interfering RNA–mediated Aggf1 silencing aggravated the repression of contractile genes by PDGF treatment (Figure IV in the online-only Data Supplement). Ad-AGGF1 infection also abrogated the acceleration of migration induced by PDGF as measured by both wound healing assay (Figure V in the online-only Data Supplement) and transwell assay (Figure VI in the online-only Data Supplement). Of note, Aggf1 overexpression did not alter PDGF signaling in HASMCs as judged by extracellular signal-regulated kinase and PDGFR phosphorylation (Figure VII in the online-only Data Supplement).

Figure 2.
Figure 2.

Angiogenic factor with G patch and FHA domains 1 (Aggf1) overexpression overcomes phenotypic modulation. A and B, Human aortic smooth muscle cells were infected with adenovirus carrying Aggf1 or an empty vector (Ad-Vec) followed by treatment with platelet-derived growth factor (PDGF). mRNA and protein levels were examined by quantitative polymerase chain reaction (qPCR; A) and Western (B). C–F, Carotid artery ligation-induced vascular injury was performed in Sprague–Dawley rats. Ad-AGGF1 or Ad-Vec virus particles were delivered by pluronic gel during surgical procedure. C, Representative hematoxylin-eosin staining showing neointima formation. Scale bar, 50 μm. D, Neointima/media layer ratio and (E) relative neointima area were calculated using Image J. n=5 rats for each group. mRNA levels were examined by qPCR (F). Scale bar, 50 μm. SM-MHC indicates smooth muscle-myosin heavy chain; and SMA-α, smooth muscle actin-α.

We then dissolved Ad-AGGF1 or Ad-NC adenoviral particles in pluronic gel and applied the gel to the adventitia during the ligation procedure. Compared with Ad-NC infection, Ad-AGGF1 infection significantly attenuated the formation of neointima (Figure 2C through 2E). In the meantime, downregulation of VSMC signature gene expression in injured carotid arteries was alleviated by Ad-AGGF1 infection (Figure 2F). Thus, it appears that Aggf1 overexpression may be able to overcome PM of VSMCs both in vitro and in vivo.

Aggf1 Modulates PM by Targeting the SRF–Myocardin Complex

SRF recruits myocardin to the CArG box located on the promoters of many SMC-specific genes to activate transcription, the disruption of which represents the paradigm of PM.14 We hypothesized that Aggf1 might play a role in this process. Coimmunoprecipitation assay suggested that Aggf1 was in a complex with myocardin (Figure 3A), whereas PDGF-BB treatment inhibited the interaction between Aggf1 and myocardin (Figure VIII in the online-only Data Supplement). In accordance, Aggf1 could be detected in the nucleus of HASMCs, and PDGF-BB treatment downregulated the levels of nuclear Aggf1. More importantly, Aggf1 was detectable on the promoters of contractile genes, albeit with lower ability of binding compared with myocardin (Figure IX in the online-only Data Supplement).

Figure 3.
Figure 3.

Angiogenic factor with G patch and FHA domains 1 (Aggf1) is essential for serum response factor (SRF)–dependent transactivation of smooth muscle cell–specific genes. A, Immunoprecipitation was performed with indicated antibodies using whole cell lysates extracted from human aortic smooth muscle cells (HASMCs). B, HASMCs were infected with adenovirus carrying Aggf1 or an empty vector (Ad-Vec) followed by treatment with platelet-derived growth factor (PDGF). Chromatin immunoprecipitation (ChIP) assay was performed with anti-MYOCARDIN. C, HASMCs were infected with adenovirus carrying Aggf1 or an empty vector (Ad-Vec) followed by treatment with PDGF. Re-ChIP assay was performed with indicated antibodies.

Whereas the occupancies of myocardin on the SMC-specific gene promoters were universally downregulated by PDGF treatment in HASMCs, Ad-AGGF1 infection reversed this trend (Figure 3B). Aggf1 overexpression enhanced the interaction between SRF and myocardin, but Aggf1 depletion weakened the SRF–myocardin interaction (Figure X in the online-only Data Supplement). Furthermore, we found that the SRF–myocardin complex formed on the SMC-specific promoters mostly collapsed in response to PDGF treatment consistent with gene transrepression, but Ad-AGGF1 infection restored the SRF–myocardin complex. This line of data indicates that Aggf1 may contribute to SMC-specific gene transactivation likely by stabilizing the SRF–myocardin interaction.

KLF4 Represses Aggf1 Transcription

Reporter assay showed that PDGF directly repressed a human Aggf1 promoter suggesting that downregulation of Aggf1 expression as a result of PDGF stimulation took place at the transcriptional level (Figure XI in the online-only Data Supplement). We next made an attempt to unveil the mechanism whereby PDGF represses Aggf1 transcription. Reporter assay using Aggf1 promoter constructs with serial deletions led to the finding that there was a PDGF response element located between −1000 and −900 bp relative to the transcription start site of the Aggf1 promoter (Figure 4A). Surveying the proximal Aggf1 promoter between −1000 and −900 bp uncovered a conserved binding motif for KLF4 (Figure XII in the online-only Data Supplement), a pre-eminent transcription factor known to promote PM.15 Chromatin immunoprecipitation (ChIP) assay confirmed that KLF4 occupancy surrounding this region of the Aggf1 promoter was significantly elevated after PDGF treatment in HASMCs; as a control, we did not detect any significant binding of KLF4 to the GAPDH promoter with or without PDGF treatment (Figure 4B). Additional evidence was sought to confirm that KLF4 mediates PDGF-induced Aggf1 transrepression. KLF4 overexpression repressed whereas KLF4 knockdown activated the Aggf1 promoter only in the presence of the intact KLF4 site as the Aggf1 promoter construct with a mutated KLF4 site did not respond to either KLF4 overexpression or KLF4 knockdown (Figure 4C and 4D). In addition, the mutated Aggf1 promoter construct failed to respond to PDGF stimulation as well (Figure 4E). Again, these effects are only observed in the presence of PDGF-BB. In light of the ChIP data (Figure 4B), which showed that the binding of KLF4 to the AGGF1 promoter under basal conditions was marginally higher than the background (IgG), we suspect that KLF4 does not constitute a rate-limiting factor in the regulation of AGGF1 transcription in normal HASMCs. Furthermore, KLF4 silencing rescued PDGF-induced loss of Aggf1 expression in HASMCs and blocked the downregulation of SMC signature genes (Figure 4F and 4G). Of interest, we found that Aggf1 silencing by small interfering RNA neutralized the effect of KLF4 knockdown (Figure 4H and 4I), suggesting that KLF4 might promote PM by, at least in part, targeting Aggf1. We, therefore, conclude that KLF4 is responsible for Aggf1 transrepression in the process of SMC PM.

Figure 4.
Figure 4.

Kruppel-like factor 4 (KLF4) represses angiogenic factor with G patch and FHA domains 1 (Aggf1) transcription. A, AGGF1 promoter constructs of different lengths were transfected into A10 cells followed by treatment with platelet-derived growth factor (PDGF). Luciferase activity was normalized to renilla activity. B, Human aortic smooth muscle cells (HASMCs) were treated with PDGF and harvested at indicated time points. chromatin immunoprecipitation (ChIP) assay was performed with anti-KLF4 or IgG. C, Wild-type (WT) AGGF1 promoter construct or AGGF1 promoter construct with mutated KLF4 site (MT) was transfected into A10 cells with or without KLF4. Luciferase activity was normalized to renilla activity. D, WT or MT AGGF1 promoter construct was transfected into A10 cells with or without KLF4 small interfering RNA (siRNA). Luciferase activity was normalized to renilla activity. E, WT or MT AGGF1 promoter construct was transfected into human embryonic kidney 293 cells followed by treatment with PDGF. Luciferase activity was normalized to renilla activity. F and G, HASMCs were transfected with KLF4 siRNA or SCR (scrambled siRNA) followed by treatment with PDGF. mRNA and protein levels were examined by quantitative polymerase chain reaction (qPCR; F) and Western (G). H and I, HASMCs were transfected with indicated siRNAs followed by treatment with PDGF. mRNA and protein levels were examined by qPCR (H) and Western (I). SM-MHC indicates smooth muscle-myosin heavy chain; and SMA-α, smooth muscle actin-α.

KLF4 Recruits HDAC11 to Repress Aggf1 Transcription

Transrepression of gene expression often involves the loss of active histone modifications surrounding the promoter region.16 Indeed, ChIP assay revealed that on PDGF stimulation, there was a simultaneous decrease in both histone H3 and H4 acetylation surrounding the Aggf1 promoter, which could be effectively blocked by KLF4 knockdown (Figure 5A). This piece of evidence alludes to a scenario wherein KLF4 represses Aggf1 transcription by recruiting a specific HDAC to remove histone acetylation rendering the chromatin surrounding the Aggf1 promoter inactive. Reporter assay showed that when a panel of HDACs, including HDAC1, HDAC2, HDAC3, HDAC4, HDAC5, HDAC7, and HDAC11, were overexpressed separately, HDAC11 repressed the Aggf1 promoter activity most potently (Figure 5B). Several lines of evidence support HDAC11 as a potential candidate in KLF4-mediated Aggf1 transrepression. First, HDAC11 expression levels were upregulated in carotid arteries in a mouse model of vascular injury (Figure XIII in the online-only Data Supplement) and in PDGF-treated HASMCs (Figure 5F and 5G). Second, HDAC11 was recruited to the Aggf1 promoter region in HASMCs after PDGF treatment as demonstrated by ChIP assay (Figure 5C). Third, HDAC11 directly interacted with KLF4 in HASMCs (Figure 5D). Fourth, PDGF evoked a stronger interaction between HDAC11 and KLF4 on the Aggf1 promoter, as measured by Re-ChIP assay, in HASMCs (Figure 5E). Fifth, HDAC11 was able to repress the activities of Aggf1 promoter constructs containing the KLF4 site but lost this ability once the KLF4 site was deleted (Figure XIV in the online-only Data Supplement). Finally, small interfering RNA–mediated depletion of HDAC11 restored Aggf1 expression in HASMCs despite the presence of PDGF while at the same time normalizing the levels of SMC signature genes at both mRNA (Figure 5F) and protein (Figure 5G) levels. It is noteworthy that Aggf1 silencing by small interfering RNA blocked the restoration of contractile gene expression as a result of HDAC11 knockdown (Figure 5H and 5I), suggesting that HDAC11 might promote PM by, at least in part, targeting Aggf1. Together, these data suggest that KLF4 recruits HDAC11 to repress Aggf1 transcription.

Figure 5.
Figure 5.

Kruppel-like factor 4 (KLF4) recruits histone deacetylase 11 (HDAC11) to repress angiogenic factor with G patch and FHA domains 1 (Aggf1) transcription. A, Human aortic smooth muscle cells (HASMCs) were transfected with KLF4 small interfering RNA (siRNA) or SCR (scrambled siRNA) followed by treatment with platelet-derived growth factor (PDGF). Chromatin immunoprecipitation (ChIP) assays were performed with anti-AcH3 and anti-AcH4. B, Aggf1 promoter luciferase construct was transfected into A10 cells with KLF4 and different HDACs. Luciferase activity was normalized to renilla activity. C, HASMCs were treated with or without PDGF for 24 h. ChIP assay was performed with anti-HDAC11 or IgG. D, Coimmunoprecipitations were performed with indicated antibodies using whole cell lysates extracted from HASMCs. E, HASMCs were treated with or without PDGF for 24 h. Re-ChIP assay was performed with indicated antibodies. F and G, HASMCs were transfected with HDAC11 siRNA or SCR followed by treatment with PDGF. mRNA and protein levels were examined by quantitative polymerase chain reaction (qPCR; F) and Western (G). H and I, HASMCs were transfected with indicated siRNAs followed by treatment with PDGF. mRNA, and protein levels were examined by qPCR (H) and Western (I). SM-MHC indicates smooth muscle-myosin heavy chain; and SMA-α, smooth muscle actin-α.

HDAC11 Inhibition Alleviates Vascular Injury

Finally, we used a small-molecule HDAC11 inhibitor (Quisinostat/HDACi) to examine the effect of HDAC11 inhibition on VSMC PM. Indeed, HDACi administration normalized Aggf1 expression and prevented PDGF-induced downregulation of VSMC-specific genes (Figure 6A and 6B). HDACi treatment, however, did not alter the Aggf1–Myocardin interaction (Figure 3A). HDACi was only effective in the presence of Aggf1 as Aggf1 knockdown pre-empted the effects of HDACi (Figure 6C and 6D).

Figure 6.
Figure 6.

Histone deacetylase 11 (HDAC11) inhibition alleviates vascular injury. A and B, Human aortic smooth muscle cells (HASMCs) were treated with platelet-derived growth factor (PDGF) and HDAC11 inhibitor (Quisinostat/HDACi) for 24 h. mRNA and protein levels were examined by quantitative polymerase chain reaction (qPCR; A) and Western (B). C and D, HASMCs were transfected with indicated small interfering RNAs followed by treatment with PDGF and HDACi for 24 h. mRNA and protein levels were examined by qPCR (C) and Western (D). E–H, Carotid artery ligation–induced vascular injury was performed in Sprague–Dawley rats. HDACi or vehicle was injected peritoneally. E, Neointima/media layer ratio and (F) relative neointima area were calculated using Image J. mRNA and protein levels were examined by qPCR (G) and immunofluorescence staining (H). Scale bar, 50 μm. I, A schematic model. CArG indicates CC(A/T)6GG; KLF4, Kruppel-like factor 4; SM-MHC, smooth muscle-myosin heavy chain; SMA-α, smooth muscle actin-α; SRF, serum response factor; and VSMC, vascular smooth muscle cell.

We then examined the effect of HDACi in vivo. In Sprague–Dawley rats, peritoneal injection of HDACi significantly attenuated the formation of neointima after carotid artery ligation (Figure 6E and 6F). In addition, quantitative polymerase chain reaction (Figure 6G) and immunofluorescence staining (Figure 6H; Figure XV in the online-only Data Supplement) showed that Aggf1 expression was restored and contractile genes were largely normalized in the injured vessels in the presence of HDACi. Combined, these data suggest that HDAC11 may play a role in SMC PM during vascular injury possibly by repressing Aggf1 transcription.

Discussion

In addition to being a proangiogenic factor in endothelial cells, Aggf1 has yet to be fully explored in the context of human pathophysiology. We present evidence here that Aggf1 plays a role in maintaining the contractile phenotype of SMCs, in part, by stabilizing the SRF–myocardin complex. It is not clear exactly how Aggf1 modulates the SRF–myocardin interaction although there exist several probable scenarios. Aggf1 is a novel binding partner for myocardin (Figure 3A). Many previously characterized myocardin-associated factors either stabilize or disrupt the SRF–myocardin complex.8 It is likely that Aggf1 may function as a scaffold to bring SRF and myocardin together. Alternatively, the ability of myocardin to associate with SRF is known to be modulated by post-translational modifications.8,17 It has recently been shown that Aggf1 is able to modulate the activities of several kinases including extracellular signal-regulated kinase18 and Akt12 although Aggf1 overexpression did not seem to alter extracellular signal-regulated kinase activity in PDGF-treated HASMC. Therefore, Aggf1 may influence the SRF–myocardin interplay by altering myocardin modifications. A careful delineation of the Aggf1–myocardin interaction could shed additional light on the mode of action for Aggf1 in the regulation of SMC PM.

We show here that KLF4 interacts with and recruits HDAC11 to repress Aggf1 transcription. HDAC11 belongs to the family of class II HDACs with high expression levels in the muscle.19 HDAC11 has been implicated in the regulation of immune response20,21 and carcinogenesis,22,23 and our data expand the territory of pathophysiological processes HDAC11 can potentially influence. There are, however, several outstanding issues on the current model. First, it remains to be determined whether HDAC11 could directly transrepress SMC signature genes or the effect of HDAC11 inhibition merely occurs secondary to the restoration of Aggf1 expression (Figure 6). Salmon et al24 have previously characterized a KLF4-centered repressor complex with HDAC2 being a core component responsible for SM22α repression during SMC PM. Because HDACs mostly function in large complexes and HDAC11 has been shown to be corecruited with HDAC2 to gene promoters in at least 1 instance,25 it is not unconceivable that HDAC11 could be steered to the SMC signature gene promoters as part of a corepressor complex by KLF4 to directly repress transcription. In the same vein, it is worthwhile to pursue a genome-wide binding pattern for HDAC11 under both physiological and pathological circumstances in SMCs. ChIP-seq analyses have identified >800 KLF4 target genes that regulate various aspects of SMC pathobiology, many previously unknown.26 It would be of great interest to determine how the interaction between HDAC11 and KLF4 plays out across the genome in SMCs. Second, we suspect that recruitment of HDAC11 by KLF4 accounts for the whole picture of Aggf1 transrepression during SMC PM. KLF4 is known to regulate transcription by coordinating various epigenetic alterations on gene promoters including DNA methylation/demethylation,27 We have recently shown that Aggf1 can be downregulated by DNA methylation in hepatic stellate cells.28 It remains to be seen whether the concerted effort of DNA methylation and histone deacetylation contributes to Aggf1 repression during SMC PM.

Our experiments performed in cultured primary HASMCs largely recapitulated the animal data that adenovirus-mediated Aggf1 overexpression in mice was able to attenuate neointima formation after vascular injury. However, ample caution should be taken when one attempts to interpret these data as Aggf1 is also expressed in the endothelial cells (Figure 1D), whereas adenovirus-mediated gene delivery is not lineage specific. Given that a volume of studies support a role for Aggf1 in regulating the pathophysiology of vascular endothelium (VE) and that a cross talk between VE and VSMC contributes to PM and vascular injury, it would be premature to conclude that the effect of Aggf1 on VSMC is strictly cell-autonomous. Because of the limitations of the experimental approaches exploited in the present study, the possibility that Aggf1 might impact SMC phenotype noncell autonomously (eg, via a paracrine pathway derived from VE) cannot be ruled out. A more delicate animal model with SMC-specific Aggf1 deficiency would more conclusively position Aggf1 as a key factor guiding the door of phenotype switch for VSMC.

Sources of Funding

This study was supported, in part, by grants from the Natural Science Foundation of China (81670223, 91439106, 81402550, 81570420, and 81503067), Natural Science Foundation of Jiangsu Province (BK20150695), Education Commission of Jiangsu Province (14KJA31001), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). Y. Xu is a Fellow at the Collaborative Innovation Center for Cardiovascular Disease Translational Medicine.

Disclosures

None.

Footnotes

  • The online-only Data Supplement is available with this article at http://atvb.ahajournals.org/lookup/suppl/doi:10.1161/ATVBAHA.117.308992/-/DC1.

  • Nonstandard Abbreviations and Acronyms
    Ad
    adenovirus
    Aggf1
    angiogenic factor with G patch and FHA domains 1
    ChIP
    chromatin immunoprecipitation
    HASMC
    human aortic smooth muscle cell
    KLF4
    kruppel-like factor 4
    PDGF
    platelet-derived growth factor
    PM
    phenotypic modulation
    SRF
    serum response factor
    VSMC
    vascular smooth muscle cell

  • Received May 12, 2016.
  • Accepted January 20, 2017.

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Highlights

  • Angiogenic factor with G patch and FHA domains 1 expression in downregulated during smooth muscle cell phenotype switch.

  • Angiogenic factor with G patch and FHA domains 1 overexpression blocks smooth muscle cell phenotypic modulation by stabilizing serum response factor–myocardin interaction.

  • Kruppel-like factor 4 recruits histone deacetylase 11 to repress angiogenic factor with G patch and FHA domains 1 transcription.

  • Histone deacetylase 11 depletion or inhibition restores angiogenic factor with G patch and FHA domains 1 expression and catapults smooth muscle cell back to the contractile phenotype.

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  • Angiogenic Factor With G Patch and FHA Domains 1 Is a Novel Regulator of Vascular InjuryHighlights
    Bisheng Zhou, Sheng Zeng, Nan Li, Liming Yu, Guang Yang, Yuyu Yang, Xinjian Zhang, Mingming Fang, Jun Xia and Yong Xu
    Arteriosclerosis, Thrombosis, and Vascular Biology. 2017;37:675-684, originally published February 2, 2017
    https://doi.org/10.1161/ATVBAHA.117.308992
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