Renal Thrombotic Microangiopathy in Mice with Combined Deletion of Endocytic Recycling Regulators EHD3 and EHD4

George, Manju; Rainey, Mark A.; Naramura, Mayumi; Foster, Kirk W.; Holzapfel, Melissa S.; Willoughby, L.; Guo, Ying; Goswami, Rasna M.; Gurumurthy, Channabasavaiah B.; Band, Vimla; Satchell, Simon C.; Band, Hamid

doi:10.1371/journal.pone.0017838

Cited by 37 publications

(63 citation statements)

References 43 publications

(58 reference statements)

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“…Glomerular TMA also occurs after administration of receptor tyrosine kinase inhibitors such as sunitinib that block VEGFR2 (57, 60) and in mice with reduced endothelial cell VEGFR2 expression (61), suggesting that anti-VEGF–associated TMA results from decreased VEGFR2 signaling. Building on this, we show that inhibiting PKC blocked the VEGF-induced CFH increase.…”

Section: Discussionmentioning

confidence: 99%

VEGF regulates local inhibitory complement proteins in the eye and kidney

Keir¹,

Firth²,

Aponik³

et al. 2016

Journal of Clinical Investigation

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125

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Outer retinal and renal glomerular functions rely on specialized vasculature maintained by VEGF that is produced by neighboring epithelial cells, the retinal pigment epithelium (RPE) and podocytes, respectively. Dysregulation of RPE- and podocyte-derived VEGF is associated with neovascularization in wet age-related macular degeneration (ARMD), choriocapillaris degeneration, and glomerular thrombotic microangiopathy (TMA). Since complement activation and genetic variants in inhibitory complement factor H (CFH) are also features of both ARMD and TMA, we hypothesized that VEGF and CFH interact. Here, we demonstrated that VEGF inhibition decreases local CFH and other complement regulators in the eye and kidney through reduced VEGFR2/PKC-α/CREB signaling. Patient podocytes and RPE cells carrying disease-associated CFH genetic variants had more alternative complement pathway deposits than controls. These deposits were increased by VEGF antagonism, a common wet ARMD treatment, suggesting that VEGF inhibition could reduce cellular complement regulatory capacity. VEGF antagonism also increased markers of endothelial cell activation, which was partially reduced by genetic complement inhibition. Together, these results suggest that VEGF protects the retinal and glomerular microvasculature, not only through VEGFR2-mediated vasculotrophism, but also through modulation of local complement proteins that could protect against complement-mediated damage. Though further study is warranted, these findings could be relevant for patients receiving VEGF antagonists.

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Section: Discussionmentioning

confidence: 99%

VEGF regulates local inhibitory complement proteins in the eye and kidney

Keir¹,

Firth²,

Aponik³

et al. 2016

Journal of Clinical Investigation

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125

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“…12 DNA was isolated from tail clips of 10 day old mice, and mice were genotyped by PCR. Three primers in a single duplex PCR reaction amplified the WT allele (377 bp) and the deleted allele (488 bp, Figure 1A).…”

Section: Methodsmentioning

confidence: 99%

EHD3-Dependent Endosome Pathway Regulates Cardiac Membrane Excitability and Physiology

Curran

Makara

Little

et al. 2014

Circulation Research

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Rationale Cardiac function is dependent on the coordinate activities of membrane ion channels, transporters, pumps, and hormone receptors to dynamically tune the membrane electrochemical gradient in response to acute and chronic stress. While our knowledge of membrane proteins has rapidly advanced over the past decade, our understanding of the subcellular pathways governing the trafficking and localization of integral membrane proteins is limited, and essentially unstudied in vivo. In heart, to our knowledge, there are no in vivo mechanistic studies that directly link endosome-based machinery with cardiac physiology. Objective Define the in vivo roles of endosome-based cellular machinery for cardiac membrane protein trafficking, myocyte excitability, and cardiac physiology. Methods and Results We identify the endosome-based EHD3 pathway as essential for cardiac physiology. EHD3−/− hearts display structural and functional defects including bradycardia and rate variability, conduction block, and blunted response to adrenergic stimulation. Mechanistically, EHD3 is critical for membrane protein trafficking, as EHD3−/− myocytes display reduced expression/localization of Na/Ca exchanger and Cav1.2 with a parallel reduction in INCX and ICa,L. Functionally, EHD3−/− myocytes show increased sarcoplasmic reticulum [Ca], increased spark frequency, and reduced expression/localization of ankyrin-B, a binding partner for EHD3 and Na/Ca exchanger. Finally, we show that in vivo EHD3−/− defects are due to cardiac-specific roles of EHD3 as mice with cardiac-selective EHD3 deficiency demonstrate both structural and electrical phenotypes. Conclusions These data provide new insight into the critical role of endosome-based pathways in membrane protein targeting and cardiac physiology. EHD3 is a critical component of protein trafficking in heart and is essential for the proper membrane targeting of select cellular proteins that maintain excitability.

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“…Deficiency-To test the in vivo cardiac intrinsic roles of EHD3, we utilized a conditional null mutant allele where the 5Ј UTR and exon 1 of the mouse EHD3 gene (Ehd3) was flanked by LoxP sites (Ehd3 f/f ) and therefore deleted in the presence of Cre recombinase (23) (Fig. 1A).…”

Section: Generation Of Cardiac-selective Mouse Model Of Ehd3mentioning

confidence: 99%