Browsing by Author "Satlin, Lisa M."

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    Effects of biomechanical forces on signaling in the cortical collecting duct (CCD)
    (American Physiological Society (APS), 2014-07-15) Carrisoza-Gaytan, Rolando; Liu, Yu; Flores, Daniel; Else, Cindy; Lee, Heon Goo; Rhodes, George; Sandoval, Ruben M.; Kleyman, Thomas R.; Lee, Francis Young-In; Molitoris, Bruce; Satlin, Lisa M.; Rohatgi, Rajeev; Department of Medicine, IU School of Medicine
    An increase in tubular fluid flow rate (TFF) stimulates Na reabsorption and K secretion in the cortical collecting duct (CCD) and subjects cells therein to biomechanical forces including fluid shear stress (FSS) and circumferential stretch (CS). Intracellular MAPK and extracellular autocrine/paracrine PGE2 signaling regulate cation transport in the CCD and, at least in other systems, are affected by biomechanical forces. We hypothesized that FSS and CS differentially affect MAPK signaling and PGE2 release to modulate cation transport in the CCD. To validate that CS is a physiological force in vivo, we applied the intravital microscopic approach to rodent kidneys in vivo to show that saline or furosemide injection led to a 46.5 ± 2.0 or 170 ± 32% increase, respectively, in distal tubular diameter. Next, murine CCD (mpkCCD) cells were grown on glass or silicone coated with collagen type IV and subjected to 0 or 0.4 dyne/cm2 of FSS or 10% CS, respectively, forces chosen based on prior biomechanical modeling of ex vivo microperfused CCDs. Cells exposed to FSS expressed an approximately twofold greater abundance of phospho(p)-ERK and p-p38 vs. static cells, while CS did not alter p-p38 and p-ERK expression compared with unstretched controls. FSS induced whereas CS reduced PGE2 release by ∼40%. In conclusion, FSS and CS differentially affect ERK and p38 activation and PGE2 release in a cell culture model of the CD. We speculate that TFF differentially regulates biomechanical signaling and, in turn, cation transport in the CCD.
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    Proximal Tubules Have the Capacity to Regulate Uptake of Albumin
    (American Society of Nephrology, 2016-02) Wagner, Mark C.; Campos-Bilderback, Silvia B.; Chowdhury, Mahboob; Flores, Brittany; Lai, Xianyin; Myslinski, Jered; Pandit, Sweekar; Sandoval, Ruben M.; Wean, Sarah E.; Wei, Yuan; Satlin, Lisa M.; Wiggins, Roger C.; Witzmann, Frank A.; Molitoris, Bruce A.; Department of Biochemistry & Molecular Biology, IU School of Medicine
    Evidence from multiple studies supports the concept that both glomerular filtration and proximal tubule (PT) reclamation affect urinary albumin excretion rate. To better understand these roles of glomerular filtration and PT uptake, we investigated these processes in two distinct animal models. In a rat model of acute exogenous albumin overload, we quantified glomerular sieving coefficients (GSC) and PT uptake of Texas Red-labeled rat serum albumin using two-photon intravital microscopy. No change in GSC was observed, but a significant decrease in PT albumin uptake was quantified. In a second model, loss of endogenous albumin was induced in rats by podocyte-specific transgenic expression of diphtheria toxin receptor. In these albumin-deficient rats, exposure to diphtheria toxin induced an increase in albumin GSC and albumin filtration, resulting in increased exposure of the PTs to endogenous albumin. In this case, PT albumin reabsorption was markedly increased. Analysis of known albumin receptors and assessment of cortical protein expression in the albumin overload model, conducted to identify potential proteins and pathways affected by acute protein overload, revealed changes in the expression levels of calreticulin, disabled homolog 2, NRF2, angiopoietin-2, and proteins involved in ATP synthesis. Taken together, these results suggest that a regulated PT cell albumin uptake system can respond rapidly to different physiologic conditions to minimize alterations in serum albumin level.
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    A reference tissue atlas for the human kidney
    (American Association for the Advancement of Science, 2022) Hansen, Jens; Sealfon, Rachel; Menon, Rajasree; Eadon, Michael T.; Lake, Blue B.; Steck, Becky; Anjani, Kavya; Parikh, Samir; Sigdel, Tara K.; Zhang, Guanshi; Velickovic, Dusan; Barwinska, Daria; Alexandrov, Theodore; Dobi, Dejan; Rashmi, Priyanka; Otto, Edgar A.; Rivera, Miguel; Rose, Michael P.; Anderton, Christopher R.; Shapiro, John P.; Pamreddy, Annapurna; Winfree, Seth; Xiong, Yuguang; He, Yongqun; de Boer, Ian H.; Hodgin, Jeffrey B.; Barisoni, Laura; Naik, Abhijit S.; Sharma, Kumar; Sarwal, Minnie M.; Zhang, Kun; Himmelfarb, Jonathan; Rovin, Brad; El-Achkar, Tarek M.; Laszik, Zoltan; He, John Cijiang; Dagher, Pierre C.; Valerius, M. Todd; Jain, Sanjay; Satlin, Lisa M.; Troyanskaya, Olga G.; Kretzler, Matthias; Iyengar, Ravi; Azeloglu, Evren U.; Kidney Precision Medicine Project; Medicine, School of Medicine
    Kidney Precision Medicine Project (KPMP) is building a spatially specified human kidney tissue atlas in health and disease with single-cell resolution. Here, we describe the construction of an integrated reference map of cells, pathways, and genes using unaffected regions of nephrectomy tissues and undiseased human biopsies from 56 adult subjects. We use single-cell/nucleus transcriptomics, subsegmental laser microdissection transcriptomics and proteomics, near-single-cell proteomics, 3D and CODEX imaging, and spatial metabolomics to hierarchically identify genes, pathways, and cells. Integrated data from these different technologies coherently identify cell types/subtypes within different nephron segments and the interstitium. These profiles describe cell-level functional organization of the kidney following its physiological functions and link cell subtypes to genes, proteins, metabolites, and pathways. They further show that messenger RNA levels along the nephron are congruent with the subsegmental physiological activity. This reference atlas provides a framework for the classification of kidney disease when multiple molecular mechanisms underlie convergent clinical phenotypes.