The Polarized Effect of Intracellular Calcium on the Renal Epithelial Sodium Channel Occurs as a Result of Subcellular Calcium Signaling Domains Maintained by Mitochondria

Thai, Tiffany L.; Yu, Ling; Galarza-Paez, Laura; Wu, Ming‐Ming; Lam, Ho Yin Colin; Bao, Hui; Duke, Billie Jeanne; Al‐Khalili, Otor; Ma, Heping; Liu, Bingchen; Eaton, Douglas C.

doi:10.1074/jbc.m115.668293

Cited by 16 publications

(9 citation statements)

References 32 publications

(35 reference statements)

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“…Multiple studies have shown ENaC is regulated by calcium [19, 32, 33]. We previously showed calcium in concert with calmodulin inhibits the MARCKS mediated PIP2 dependent regulation of ENaC [19].…”

Section: Introductionmentioning

confidence: 99%

Exosomal GAPDH from Proximal Tubule Cells Regulate ENaC Activity

Jella

Yue

et al. 2016

PLoS ONE

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Exosomes are nanometer-scale, cell-derived vesicles that contain various molecules including nucleic acids, proteins, and lipids. These vesicles can release their cargo into adjacent or distant cells and mediate intercellular communication and cellular function. Here we examined the regulation of epithelial sodium channels in mpkCCD cells and distal tubule Xenopus 2F3 cells by exosomes isolated from proximal tubule LLC-PK1 cells. Cultured mpkCCD cells were stained with CTX coupled to a green fluorophore in order to label the cell membranes and freshly isolated exosomes from LLC-PK1 cells were labeled with the red lipophilic dye PKH26 in order to visualize uptake of exosomes into the cells. Single-channel patch clamp recordings showed the open probability of ENaC in Xenopus 2F3 cells and in freshly isolated split-open tubules decreased in response to exogenous application of exosomes derived from LLC-PK1 proximal tubule cells. Active GAPDH was identified within exosomes derived from proximal tubule LLC-PK1 cells. The effect on ENaC activity in Xenopus 2F3 cells was blunted after application of exosomes transfected with the GAPDH inhibitor heptelidic acid. Also, we show GAPDH and ENaC subunits associate in mpkCCD cells. These studies examine a potential role for exosomes in the regulation of ENaC activity and examine a possible mechanism for communication from proximal tubule cells to distal tubule and collecting duct cells.

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Section: Introductionmentioning

confidence: 99%

Exosomal GAPDH from Proximal Tubule Cells Regulate ENaC Activity

Jella

Yue

et al. 2016

PLoS ONE

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“…Previous studies have shown that a strong elevation of intracellular Ca 2ϩ (Ͼ 1 M) is required to activate TRPM4 (13,21). Our data indicate that the Ca 2ϩ sensitivity of TRPM4 channels in the cultured mpkCCD c14 cells is even lower than those previously reported in other cell types, which has an EC 50 of 32.6 M. Our recent studies suggest that mitochondria can form a band below the apical membrane of CCD principal cells to function as a Ca 2ϩ barrier (34). This mitochondria band may take up the released Ca 2ϩ which is induced by ATP before it diffuses to the apical membrane where the channel is located.…”

Section: Discussionmentioning

confidence: 50%

Hydrogen peroxide suppresses TRPM4 trafficking to the apical membrane in mouse cortical collecting duct principal cells

Zhai

et al. 2016

American Journal of Physiology-Renal Physiology

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A Ca-activated nonselective cation channel (NSC) is found in principal cells of the mouse cortical collecting duct (CCD). However, the molecular identity of this channel remains unclear. We used mpkCCD cells, a mouse CCD principal cell line, to determine whether NSC represents the transient receptor potential (TRP) channel, the melastatin subfamily 4 (TRPM4). A Ca-sensitive single-channel current was observed in inside-out patches excised from the apical membrane of mpkCCD cells. Like TRPM4 channels found in other cell types, this channel has an equal permeability for Na and K and has a linear current-voltage relationship with a slope conductance of ~23 pS. The channel was inhibited by a specific TRPM4 inhibitor, 9-phenanthrol. Moreover, the frequency of observing this channel was dramatically decreased in TRPM4 knockdown mpkCCD cells. Unlike those previously reported in other cell types, the TRPM4 in mpkCCD cells was unable to be activated by hydrogen peroxide (HO). Conversely, after treatment with HO, TRPM4 density in the apical membrane of mpkCCD cells was significantly decreased. The channel in intact cell-attached patches was activated by ionomycin (a Ca ionophore), but not by ATP (a purinergic P receptor agonist). These data suggest that the NSC current previously described in CCD principal cells is actually carried through TRPM4 channels. However, the physiological role of this channel in the CCD remains to be further determined.

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“…It should be noted that Shaughnessy et al [ 54 ] observed that listeriolysin O pores generated by the bacterium in the process of primary vacuolar escape allow Ca 2+ in the vacuole to leak into the cytoplasm, albeit slowly. It is possible that calcium binding promotes changes in InlP behavior that are specific to different calcium microdomains in the polarized epithelium [ 55 , 56 ], including microdomains potentially specific to basal protrusions and/or placental trophoblasts [ 57 ].…”

Section: Discussionmentioning

confidence: 99%

Listeria monocytogenes InlP interacts with afadin and facilitates basement membrane crossing

et al. 2018

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During pregnancy, the placenta protects the fetus against the maternal immune response, as well as bacterial and viral pathogens. Bacterial pathogens that have evolved specific mechanisms of breaching this barrier, such as Listeria monocytogenes, present a unique opportunity for learning how the placenta carries out its protective function. We previously identified the L. monocytogenes protein Internalin P (InlP) as a secreted virulence factor critical for placental infection. Here, we show that InlP, but not the highly similar L. monocytogenes internalin Lmo2027, binds to human afadin (encoded by AF-6), a protein associated with cell-cell junctions. A crystal structure of InlP reveals several unique features, including an extended leucine-rich repeat (LRR) domain with a distinctive Ca2+-binding site. Despite afadin’s involvement in the formation of cell-cell junctions, MDCK epithelial cells expressing InlP displayed a decrease in the magnitude of the traction stresses they could exert on deformable substrates, similar to the decrease in traction exhibited by AF-6 knock-out MDCK cells. L. monocytogenes ΔinlP mutants were deficient in their ability to form actin-rich protrusions from the basal face of polarized epithelial monolayers, a necessary step in the crossing of such monolayers (transcytosis). A similar phenotype was observed for bacteria expressing an internal in-frame deletion in inlP (inlP ΔLRR5) that specifically disrupts its interaction with afadin. However, afadin deletion in the host cells did not rescue the transcytosis defect. We conclude that secreted InlP targets cytosolic afadin to specifically promote L. monocytogenes transcytosis across the basal face of epithelial monolayers, which may contribute to the crossing of the basement membrane during placental infection.

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The Polarized Effect of Intracellular Calcium on the Renal Epithelial Sodium Channel Occurs as a Result of Subcellular Calcium Signaling Domains Maintained by Mitochondria

Cited by 16 publications

References 32 publications

Exosomal GAPDH from Proximal Tubule Cells Regulate ENaC Activity

Exosomal GAPDH from Proximal Tubule Cells Regulate ENaC Activity

Hydrogen peroxide suppresses TRPM4 trafficking to the apical membrane in mouse cortical collecting duct principal cells

Listeria monocytogenes InlP interacts with afadin and facilitates basement membrane crossing

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