1
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Burmakin M, Gilmour PS, Gram M, Shushakova N, Sandoval RM, Molitoris BA, Larsson TE. Therapeutic α-1-microglobulin ameliorates kidney ischemia-reperfusion injury. Am J Physiol Renal Physiol 2024; 327:F103-F112. [PMID: 38779750 DOI: 10.1152/ajprenal.00067.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/12/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024] Open
Abstract
α-1-Microglobulin (A1M) is a circulating glycoprotein with antioxidant, heme-binding, and mitochondrial protection properties. The investigational drug RMC-035, a modified therapeutic A1M protein, was assessed for biodistribution and pharmacological activity in a broad set of in vitro and in vivo experiments, supporting its clinical development. Efficacy and treatment posology were assessed in various models of kidney ischemia and reperfusion injury (IRI). Real-time glomerular filtration rate (GFR), functional renal biomarkers, tubular injury biomarkers (NGAL and KIM-1), and histopathology were evaluated. Fluorescently labeled RMC-035 was used to assess biodistribution. RMC-035 demonstrated consistent and reproducible kidney protection in rat IRI models as well as in a model of IRI imposed on renal impairment and in a mouse IRI model, where it reduced mortality. Its pharmacological activity was most pronounced with combined dosing pre- and post-ischemia and weaker with either pre- or post-ischemia dosing alone. RMC-035 rapidly distributed to the kidneys via glomerular filtration and selective luminal uptake by proximal tubular cells. IRI-induced expression of kidney heme oxygenase-1 was inhibited by RMC-035, consistent with its antioxidative properties. RMC-035 also dampened IRI-associated inflammation and improved mitochondrial function, as shown by tubular autofluorescence. Taken together, the efficacy of RMC-035 is congruent with its targeted mechanism(s) and biodistribution profile, supporting its further clinical evaluation as a novel kidney-protective therapy.NEW & NOTEWORTHY A therapeutic A1M protein variant (RMC-035) is currently in phase 2 clinical development for renal protection in patients undergoing open-chest cardiac surgery. It targets several key pathways underlying kidney injury in this patient group, including oxidative stress, heme toxicity, and mitochondrial dysfunction. RMC-035 is rapidly eliminated from plasma, distributing to kidney proximal tubules, and demonstrates dose-dependent efficacy in numerous models of ischemia-reperfusion injury, particularly when administered before ischemia. These results support its continued clinical evaluation.
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Affiliation(s)
- Mikhail Burmakin
- Division of Pathology, Department of Laboratory Medicine, Karolinska Institute, Huddinge, Sweden
- Guard Therapeutics International AB, Stockholm, Sweden
| | | | - Magnus Gram
- Pediatrics, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
- Department of Neonatology, Skåne University Hospital, Lund, Sweden
- Biofilms - Research Center for Biointerfaces, Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö, Sweden
| | - Nelli Shushakova
- Renal Disease and Transplantation, Phenos GmbH, Hannover, Germany
- Department of Nephrology, Hannover Medical School, Hannover, Germany
| | - Ruben M Sandoval
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Bruce A Molitoris
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Tobias E Larsson
- Guard Therapeutics International AB, Stockholm, Sweden
- Division of Nephrology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Huddinge, Sweden
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2
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Baldelomar EJ, Charlton JR, Bennett KM. Mapping single-nephron filtration in the isolated, perfused rat kidney using magnetic resonance imaging. Am J Physiol Renal Physiol 2022; 323:F602-F611. [PMID: 36049066 PMCID: PMC9602809 DOI: 10.1152/ajprenal.00103.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 08/16/2022] [Accepted: 08/25/2022] [Indexed: 12/14/2022] Open
Abstract
The kidney has an extraordinary ability to maintain glomerular filtration despite natural fluctuations in blood pressure and nephron loss. This is partly due to local coordination between single-nephron filtration and vascular perfusion. An improved understanding of the three-dimensional (3-D) functional coordination between nephrons and the vasculature may provide a new perspective of the heterogeneity of kidney function and could inform targeted therapies and timed interventions to slow or prevent the progression of kidney disease. Here, we developed magnetic resonance imaging (MRI) tools to visualize single-nephron function in 3-D throughout the isolated perfused rat kidney. We used an intravenous slow perfusion of a glomerulus-targeted imaging tracer [cationized ferritin (CF)] to map macromolecular dynamics and to identify glomeruli in 3-D, followed by a bolus of a freely filtered tracer (gadolinium diethylenetriamine penta-acetic acid) to map filtration kinetics. There was a wide intrakidney distribution of CF binding rates and estimated single-nephron glomerular filtration rate (eSNGFR) between nephrons. eSNGFR and CF uptake rates did not vary significantly by distance from the kidney surface. eSNGFR varied from ∼10 to ∼100 nL/min throughout the kidney. Whole single-kidney GFR was similar across all kidneys, despite differences in the distributions eSNGFR of and glomerular number, indicating a robust adaptive regulation of individual nephrons to maintain constant single-kidney GFR in the presence of a natural variation in nephron number. This work provides a framework for future studies of single-nephron function in the whole isolated perfused kidney and experiments of single-nephron function in vivo using MRI.NEW & NOTEWORTHY We report MRI tools to measure and map single-nephron function in the isolated, perfused rat kidney. We used imaging tracers to identify nephrons throughout the kidney and to measure the delivery and filtration of the tracers at the location of the glomeruli. With this technique, we directly measured physiological parameters including estimated single-nephron glomerular filtration rate throughout the kidney. This work provides a foundation for new studies to simultaneously map the function of large numbers of nephrons.
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Affiliation(s)
- Edwin J Baldelomar
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
| | - Jennifer R Charlton
- Division of Nephrology, Department of Pediatrics, University of Virginia, Charlottesville, Virginia
| | - Kevin M Bennett
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
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3
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Arulkumaran N, Pollen SJ, Tidswell R, Gaupp C, Peters VBM, Stanzani G, Snow TAC, Duchen MR, Singer M. Selective mitochondrial antioxidant MitoTEMPO reduces renal dysfunction and systemic inflammation in experimental sepsis. Br J Anaesth 2021; 127:577-586. [PMID: 34332740 DOI: 10.1016/j.bja.2021.05.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/04/2021] [Accepted: 05/27/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Excess mitochondrial reactive oxygen species (mROS) in sepsis is associated with organ failure, in part by generating inflammation through the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome. We determined the impact of a mitochondrial-targeted antioxidant (MitoTEMPO) on mitochondrial dysfunction in renal proximal tubular epithelial cells, peritoneal immune cell function ex vivo, and organ dysfunction in a rat model of sepsis. METHODS The effects of MitoTEMPO were assessed ex vivo using adenosine triphosphate and lipopolysaccharide-stimulated rat peritoneal immune cells and fresh rat kidney slices exposed to serum from septic rats. We assessed mROS production and phagocytotic capacity (flow cytometry), mitochondrial functionality (multiphoton imaging, respirometry), and NLRP3 inflammasome activation in cell culture. The effect of MitoTEMPO on organ dysfunction was evaluated in a rat model of faecal peritonitis. RESULTS MitoTEMPO decreased septic serum-induced mROS (P<0.001) and maintained normal reduced nicotinamide adenine dinucleotide redox state (P=0.02) and mitochondrial membrane potential (P<0.001) in renal proximal tubular epithelial cells ex vivo. In lipopolysaccharide-stimulated peritoneal immune cells, MitoTEMPO abrogated the increase in mROS (P=0.006) and interleukin-1β (IL-1β) (P=0.03) without affecting non-mitochondrial oxygen consumption or the phagocytotic-induced respiratory burst (P>0.05). In vivo, compared with untreated septic animals, MitoTEMPO reduced systemic IL-1β (P=0.01), reduced renal oxidative stress as determined by urine isoprostane levels (P=0.04), and ameliorated renal dysfunction (reduced serum urea (P<0.001) and creatinine (P=0.05). CONCLUSIONS Reduction of mROS by a mitochondria-targeted antioxidant reduced IL-1β, and protected mitochondrial, cellular, and organ functionality after septic insults.
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Affiliation(s)
- Nishkantha Arulkumaran
- Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, London, UK.
| | - Sean J Pollen
- Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, London, UK
| | - Robert Tidswell
- Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, London, UK
| | - Charlotte Gaupp
- Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, London, UK
| | - Vera B M Peters
- Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, London, UK
| | - Giacomo Stanzani
- Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, London, UK
| | - Timothy A C Snow
- Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, London, UK
| | - Michael R Duchen
- Department of Cell and Development Biology, University College London, London, UK
| | - Mervyn Singer
- Bloomsbury Institute of Intensive Care Medicine, Division of Medicine, University College London, London, UK
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4
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Abstract
Kidneys are highly aerobic organs and their function is tightly coupled to mitochondrial energy production. Renal tubular cells, particularly the proximal tubule (PT), require an abundance of mitochondria to provide sufficient energy for regulating fluid and electrolyte balance. Meanwhile, mitochondrial defects are implicated in a range of different kidney diseases. Multiphoton microscopy (MP) is a powerful tool that allows detailed study of mitochondrial morphology, dynamics, and function in kidney tissue. Here, we describe how MP can be used to image mitochondria in kidney tubular cells, either ex vivo in tissue slices or in vivo in living rodents, using both endogenous and exogenous fluorescent molecules. Moreover, changes in mitochondrial signals can be followed in real time in response to different insults or stimuli, in parallel with other important readouts of kidney tubular function, such as solute uptake and trafficking.
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Affiliation(s)
- Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Susan Ghazi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Andrew M Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland.
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5
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Ranjit S, Lanzanò L, Libby AE, Gratton E, Levi M. Advances in fluorescence microscopy techniques to study kidney function. Nat Rev Nephrol 2020; 17:128-144. [PMID: 32948857 DOI: 10.1038/s41581-020-00337-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2020] [Indexed: 02/07/2023]
Abstract
Fluorescence microscopy, in particular immunofluorescence microscopy, has been used extensively for the assessment of kidney function and pathology for both research and diagnostic purposes. The development of confocal microscopy in the 1950s enabled imaging of live cells and intravital imaging of the kidney; however, confocal microscopy is limited by its maximal spatial resolution and depth. More recent advances in fluorescence microscopy techniques have enabled increasingly detailed assessment of kidney structure and provided extraordinary insights into kidney function. For example, nanoscale precise imaging by rapid beam oscillation (nSPIRO) is a super-resolution microscopy technique that was originally developed for functional imaging of kidney microvilli and enables detection of dynamic physiological events in the kidney. A variety of techniques such as fluorescence recovery after photobleaching (FRAP), fluorescence correlation spectroscopy (FCS) and Förster resonance energy transfer (FRET) enable assessment of interaction between proteins. The emergence of other super-resolution techniques, including super-resolution stimulated emission depletion (STED), photoactivated localization microscopy (PALM), stochastic optical reconstruction microscopy (STORM) and structured illumination microscopy (SIM), has enabled functional imaging of cellular and subcellular organelles at ≤50 nm resolution. The deep imaging via emission recovery (DIVER) detector allows deep, label-free and high-sensitivity imaging of second harmonics, enabling assessment of processes such as fibrosis, whereas fluorescence lifetime imaging microscopy (FLIM) enables assessment of metabolic processes.
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Affiliation(s)
- Suman Ranjit
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC, USA. .,Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA, USA.
| | - Luca Lanzanò
- Nanoscopy and NIC@IIT, Istituto Italiano di Tecnologia, Genoa, Italy.,Department of Physics and Astronomy "Ettore Majorana", University of Catania, Catania, Italy
| | - Andrew E Libby
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC, USA
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, CA, USA.
| | - Moshe Levi
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, Washington, DC, USA.
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6
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Martins JR, Haenni D, Bugarski M, Figurek A, Hall AM. Quantitative intravital Ca2+ imaging maps single cell behavior to kidney tubular structure. Am J Physiol Renal Physiol 2020; 319:F245-F255. [DOI: 10.1152/ajprenal.00052.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Ca2+ is an important second messenger that translates extracellular stimuli into intracellular responses. Although there has been significant progress in understanding Ca2+ dynamics in organs such as the brain, the nature of Ca2+ signals in the kidney is still poorly understood. Here, we show that by using a genetically expressed highly sensitive reporter (GCaMP6s), it is possible to perform imaging of Ca2+ signals at high resolution in the mouse kidney in vivo. Moreover, by applying machine learning-based automated analysis using a Ca2+-independent signal, quantitative data can be extracted in an unbiased manner. By projecting the resulting data onto the structure of the kidney, we show that different tubular segments display highly distinct spatiotemporal patterns of Ca2+ signals. Furthermore, we provide evidence that Ca2+ activity in the proximal tubule decreases with increasing distance from the glomerulus. Finally, we demonstrate that substantial changes in intracellular Ca2+ can be detected in proximal tubules in a cisplatin model of acute kidney injury, which can be linked to alterations in cell structure and transport function. In summary, we describe a powerful new tool to investigate how single cell behavior is integrated with whole organ structure and function and how it is altered in disease states relevant to humans.
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Affiliation(s)
| | - Dominik Haenni
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Andreja Figurek
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Andrew M. Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
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7
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Wu S, Guo H, Horng H, Liu Y, Li H, Daneshpajouhnejad P, Rosenberg A, Albanese C, Ranjit S, Andrews PM, Levi M, Tang Q, Chen Y. Morphological and functional characteristics of aging kidneys based on two-photon microscopy in vivo. JOURNAL OF BIOPHOTONICS 2020; 13:e201900246. [PMID: 31688977 DOI: 10.1002/jbio.201900246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/29/2019] [Accepted: 10/29/2019] [Indexed: 05/08/2023]
Abstract
Age-related kidney disease, which is chronic and naturally occurring, is a general term for a set of heterogeneous disorders affecting kidney structures and characterized by a decline in renal function. Age-related renal insufficiency has important implications with regard to body homeostasis, drug toxicity and renal transplantation. In our study, two-photon microscopy was used to image kidney morphological and functional characteristics in an age-related rat model in vivo. The changes in morphology are analyzed based on autofluorescence and Hoechst 33342 labeling in rats with different ages. Structural parameters including renal tubular diameter, cell nuclei density, size and shape are studied and compared with Hematoxylin and Eosin histological analysis. Functional characteristics, such as blood flow, and glomerular filtration rate are studied with high-molecular weight (MW) 500-kDa dextran-fluorescein and low-MW 10-kDa dextran-rhodamine. Results indicate that morphology changes significantly and functional characteristics deteriorate with age. These parameters are potential indicators for evaluating age-related renal morphology and function changes. Combined analyses of these parameters could provide a quantitative, novel method for monitoring kidney diseases and/or therapeutic effects of kidney drugs.
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Affiliation(s)
- Shulian Wu
- Fujian Provincial Key Laboratory of Photonic Technology, Key Laboratory of Optoelectronic Science and Technology for Medicine, College of Photonic and Electronic Engineering, Fujian Normal University, Ministry of Education, Fuzhou, China
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Hengchang Guo
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Hannah Horng
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Yi Liu
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
| | - Hui Li
- Fujian Provincial Key Laboratory of Photonic Technology, Key Laboratory of Optoelectronic Science and Technology for Medicine, College of Photonic and Electronic Engineering, Fujian Normal University, Ministry of Education, Fuzhou, China
| | | | - Avi Rosenberg
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Christopher Albanese
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC
| | - Suman Ranjit
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC
| | - Peter M Andrews
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC
| | - Moshe Levi
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC
| | - Qinggong Tang
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
- Stephenson School of Biomedical Engineering, University of Oklahoma, Norman, Oklahoma
| | - Yu Chen
- Fujian Provincial Key Laboratory of Photonic Technology, Key Laboratory of Optoelectronic Science and Technology for Medicine, College of Photonic and Electronic Engineering, Fujian Normal University, Ministry of Education, Fuzhou, China
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland
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8
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Ghazi S, Polesel M, Hall AM. Targeting glycolysis in proliferative kidney diseases. Am J Physiol Renal Physiol 2019; 317:F1531-F1535. [DOI: 10.1152/ajprenal.00460.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Glycolytic activity is increased in proliferating cells, leading to the concept that glycolysis could be a therapeutic target in cystic diseases and kidney cancer. Preclinical studies using the glucose analog 2-deoxy-d-glucose have shown promise; however, inhibiting glycolysis in humans is unlikely to be without risks. While proximal tubules are predominantly aerobic, later segments are more glycolytic. Understanding exactly where and why glycolysis is important in the physiology of the distal nephron is thus crucial in predicting potential adverse effects of glycolysis inhibitors. Live imaging techniques could play an important role in the process of characterizing cellular metabolism in the functioning kidney. The goal of this review is to briefly summarize recent findings on targeting glycolysis in proliferative kidney diseases and to highlight the necessity for future research focusing on glycolysis in the healthy kidney.
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Affiliation(s)
- Susan Ghazi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | | | - Andrew M. Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
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9
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Rowland R, Ponticorvo A, Jarrin Lopez A, Li S, Li X, Ichii H, Durkin AJ. Monitoring kidney optical properties during cold storage preservation with spatial frequency domain imaging. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-7. [PMID: 31777223 PMCID: PMC6882458 DOI: 10.1117/1.jbo.24.11.116003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/11/2019] [Indexed: 05/18/2023]
Abstract
Transplantation of kidneys results in delayed graft function in as many as 40% of cases. During the organ transplantation process, donor kidneys undergo a period of cold ischemic time (CIT), where the organ is preserved with a cold storage solution to maintain tissue viability. Some complications observed after grafting may be due to damage sustained to the kidney during CIT. However, the effects due to this damage are not apparent until well after transplant surgery has concluded. To this end, we have used spatial frequency domain imaging (SFDI) to measure spatially resolved optical properties of porcine kidneys over the course of 80-h CIT. During this time, we observed an increase in both reduced scattering (μ s& ' ) and absorption (μa) coefficients. The measured scattering b parameter increased until 24 h of CIT, then returned toward baseline during the remaining duration of the imaging sequence. These results show that the optical properties of kidney tissue change with increasing CIT and suggest that continued investigation into the application of SFDI to kidneys under CIT may lead to the development of a noninvasive method for assessing graft viability.
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Affiliation(s)
- Rebecca Rowland
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
| | - Adrien Ponticorvo
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
| | - Alberto Jarrin Lopez
- University of California, Irvine, Department of Surgery, UC Irvine Division of Transplantation, Orange, California, United States
| | - Shiri Li
- University of California, Irvine, Department of Surgery, UC Irvine Division of Transplantation, Orange, California, United States
| | - Xiaodong Li
- UC Irvine Health Douglas Hospital, Department of Pathology, Orange, California, United States
| | - Hirohito Ichii
- University of California, Irvine, Department of Surgery, UC Irvine Division of Transplantation, Orange, California, United States
| | - Anthony J. Durkin
- University of California, Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States
- University of California, Irvine, Department of Biomedical Engineering, Irvine, California, United States
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10
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Evans TA, Barkauskas DS, Silver J. Intravital imaging of immune cells and their interactions with other cell types in the spinal cord: Experiments with multicolored moving cells. Exp Neurol 2019; 320:112972. [PMID: 31234058 DOI: 10.1016/j.expneurol.2019.112972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/25/2019] [Accepted: 06/04/2019] [Indexed: 12/25/2022]
Abstract
Intravital imaging of the immune system is a powerful technique for studying biology of the immune response in the spinal cord using a variety of disease models ranging from traumatic injury to autoimmune disorders. Here, we will discuss specific technical aspects as well as many intriguing biological phenomena that have been revealed with the use of intravital imaging for investigation of the immune system in the spinal cord. We will discuss surgical techniques for exposing and stabilizing the spine that are critical for obtaining images, visualizing immune and CNS cells with genetically expressed fluorescent proteins, fluorescent labeling techniques and briefly discuss some of the challenges of image analysis.
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Affiliation(s)
- Teresa A Evans
- Department of Pediatrics, Stanford University, Stanford, CA, USA.
| | | | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
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11
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Su XT, Saritas T, Ellison DH. Optical tissue clearing and immunolabeling in kidney research. Methods Cell Biol 2019; 154:31-41. [DOI: 10.1016/bs.mcb.2019.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Early loss of mitochondrial complex I and rewiring of glutathione metabolism in renal oncocytoma. Proc Natl Acad Sci U S A 2018; 115:E6283-E6290. [PMID: 29915083 PMCID: PMC6142220 DOI: 10.1073/pnas.1711888115] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Renal oncocytomas are benign kidney tumors with numerous mitochondria. Here, we analyze the mitochondrial (mtDNA) and nuclear genomes of these tumors. Our analysis finds mtDNA mutations in complex I (the first step in mitochondrial respiration) to be early genetic events that likely contribute to tumor formation. Since mtDNA mutations can lead to severe degenerative disorders, the cellular responses allowing renal oncocytoma cells to grow are important to consider. To properly understand authentic gene expression changes in tumors, we found it important to consider the gene expression pattern of the tumor’s cell of origin, the distal nephron. By doing so, we uncover alterations in glutathione synthesis and turnover that likely represent an adaptive metabolic response in renal oncocytoma. Renal oncocytomas are benign tumors characterized by a marked accumulation of mitochondria. We report a combined exome, transcriptome, and metabolome analysis of these tumors. Joint analysis of the nuclear and mitochondrial (mtDNA) genomes reveals loss-of-function mtDNA mutations occurring at high variant allele fractions, consistent with positive selection, in genes encoding complex I as the most frequent genetic events. A subset of these tumors also exhibits chromosome 1 loss and/or cyclin D1 overexpression, suggesting they follow complex I loss. Transcriptome data revealed that many pathways previously reported to be altered in renal oncocytoma were simply differentially expressed in the tumor’s cell of origin, the distal nephron, compared with other nephron segments. Using a heuristic approach to account for cell-of-origin bias we uncovered strong expression alterations in the gamma-glutamyl cycle, including glutathione synthesis (increased GCLC) and glutathione degradation. Moreover, the most striking changes in metabolite profiling were elevations in oxidized and reduced glutathione as well as γ-glutamyl-cysteine and cysteinyl-glycine, dipeptide intermediates in glutathione biosynthesis, and recycling, respectively. Biosynthesis of glutathione appears adaptive as blockade of GCLC impairs viability in cells cultured with a complex I inhibitor. Our data suggest that loss-of-function mutations in complex I are a candidate driver event in renal oncocytoma that is followed by frequent loss of chromosome 1, cyclin D1 overexpression, and adaptive up-regulation of glutathione biosynthesis.
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13
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Abstract
Kidney cell death plays a key role in the progression of life-threatening renal diseases, such as acute kidney injury and chronic kidney disease. Injured and dying epithelial and endothelial cells take part in complex communication with the innate immune system, which drives the progression of cell death and the decrease in renal function. To improve our understanding of kidney cell death dynamics and its impact on renal disease, a study approach is needed that facilitates the visualization of renal function and morphology in real time. Intravital multiphoton microscopy of the kidney has been used for more than a decade and made substantial contributions to our understanding of kidney physiology and pathophysiology. It is a unique tool that relates renal structure and function in a time- and spatial-dependent manner. Basic renal function, such as microvascular blood flow regulation and glomerular filtration, can be determined in real time and homeostatic alterations, which are linked inevitably to cell death and can be depicted down to the subcellular level. This review provides an overview of the available techniques to study kidney dysfunction and inflammation in terms of cell death in vivo, and addresses how this novel approach can be used to improve our understanding of cell death dynamics in renal disease.
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14
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Abstract
Intravital two-photon microscopy is a powerful imaging tool for investigating various biological processes in live animals. This chapter describes an overview of intravital imaging of the rodent kidney including animal surgery, characteristics of renal tubular autofluorescence, in vivo use of fluorescent probes, and renal immune-cell tracking.
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Affiliation(s)
- Takashi Hato
- Department of Medicine, Indiana University, Indianapolis, IN, USA
| | - Seth Winfree
- Department of Medicine, Indiana University, Indianapolis, IN, USA
| | - Pierre C Dagher
- Department of Medicine, Indiana University, Indianapolis, IN, USA.
- Division of Nephrology, Indiana University, Indianapolis, IN, USA.
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15
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Intravital imaging of the kidney. Methods 2017; 128:33-39. [PMID: 28410977 DOI: 10.1016/j.ymeth.2017.03.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/24/2017] [Accepted: 03/30/2017] [Indexed: 02/06/2023] Open
Abstract
Two-photon intravital microscopy is a powerful tool that allows the examination of dynamic cellular processes in the live animal with unprecedented resolution. Indeed, it offers the ability to address unique biological questions that may not be solved by other means. While two-photon intravital microscopy has been successfully applied to study many organs, the kidney presents its own unique challenges that need to be overcome in order to optimize and validate imaging data. For kidney imaging, the complexity of renal architecture and salient autofluorescence merit special considerations as these elements directly impact image acquisition and data interpretation. Here, using illustrative cases, we provide practical guides and discuss issues that may arise during two-photon live imaging of the rodent kidney.
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16
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Abstract
The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. This is a prerequisite for studying the physiology of the isolated organ and for many innovative applications that may be possible in the future, including perfusion decellularization for kidney bioengineering or the administration of anti-rejection or genome-editing drugs in high doses to prime the kidney for transplantation. During the time of the perfusion, the kidney can be manipulated, renal function can be assessed, and various pharmaceuticals administered. After the procedure, the kidney can be transplanted or processed for molecular biology, biochemical analysis, or microscopy. This paper describes the perfusate and the surgical technique needed for the ex vivo perfusion of mouse kidneys. Details of the perfusion apparatus are given and data are presented showing the viability of the kidney's preparation: renal blood flow, vascular resistance, and urine data as functional, transmission electron micrographs of different nephron segments as morphological readouts, and western blots of transport proteins of different nephron segments as molecular readout.
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Affiliation(s)
- Jan Czogalla
- Institute of Anatomy, Swiss National Centre of Competence in Research Kidney, University of Zürich;
| | | | - Johannes Loffing
- Institute of Anatomy, Swiss National Centre of Competence in Research Kidney, University of Zürich
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17
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Schießl IM, Castrop H. Deep insights: intravital imaging with two-photon microscopy. Pflugers Arch 2016; 468:1505-16. [PMID: 27352273 DOI: 10.1007/s00424-016-1832-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 04/26/2016] [Indexed: 01/03/2023]
Abstract
Intravital multiphoton microscopy is widely used to assess the structure and function of organs in live animals. Although different tissues vary in their accessibility for intravital multiphoton imaging, considerable progress has been made in the imaging quality of all tissues due to substantial technical improvements in the relevant imaging components, such as optics, excitation laser, detectors, and signal analysis software. In this review, we provide an overview of the technical background of intravital multiphoton microscopy. Then, we note a few seminal findings that were made through the use of multiphoton microscopy. Finally, we address the technical limitations of the method and provide an outlook for how these limitations may be overcome through future technical developments.
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Affiliation(s)
- Ina Maria Schießl
- Institute of Physiology, University of Regensburg, Universitätsstr. 31, 93040, Regensburg, Germany.
| | - Hayo Castrop
- Institute of Physiology, University of Regensburg, Universitätsstr. 31, 93040, Regensburg, Germany
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18
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Autophagy, Innate Immunity and Tissue Repair in Acute Kidney Injury. Int J Mol Sci 2016; 17:ijms17050662. [PMID: 27153058 PMCID: PMC4881488 DOI: 10.3390/ijms17050662] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/14/2016] [Accepted: 04/20/2016] [Indexed: 01/09/2023] Open
Abstract
Kidney is a vital organ with high energy demands to actively maintain plasma hemodynamics, electrolytes and water homeostasis. Among the nephron segments, the renal tubular epithelium is endowed with high mitochondria density for their function in active transport. Acute kidney injury (AKI) is an important clinical syndrome and a global public health issue with high mortality rate and socioeconomic burden due to lack of effective therapy. AKI results in acute cell death and necrosis of renal tubule epithelial cells accompanied with leakage of tubular fluid and inflammation. The inflammatory immune response triggered by the tubular cell death, mitochondrial damage, associative oxidative stress, and the release of many tissue damage factors have been identified as key elements driving the pathophysiology of AKI. Autophagy, the cellular mechanism that removes damaged organelles via lysosome-mediated degradation, had been proposed to be renoprotective. An in-depth understanding of the intricate interplay between autophagy and innate immune response, and their roles in AKI pathology could lead to novel therapies in AKI. This review addresses the current pathophysiology of AKI in aspects of mitochondrial dysfunction, innate immunity, and molecular mechanisms of autophagy. Recent advances in renal tissue regeneration and potential therapeutic interventions are also discussed.
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19
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Gandhirajan RK, Jain M, Walla B, Johnsen M, Bartram MP, Huynh Anh M, Rinschen MM, Benzing T, Schermer B. Cysteine S-Glutathionylation Promotes Stability and Activation of the Hippo Downstream Effector Transcriptional Co-activator with PDZ-binding Motif (TAZ). J Biol Chem 2016; 291:11596-607. [PMID: 27048650 DOI: 10.1074/jbc.m115.712539] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Indexed: 11/06/2022] Open
Abstract
Transcriptional co-activator with PDZ-binding motif (TAZ) and Yes-associated protein (YAP) are critical transcriptional co-activators downstream of the Hippo pathway involved in the regulation of organ size, tissue regeneration, proliferation, and apoptosis. Recent studies suggested common and distinct functions of TAZ and YAP and their diverse impact under several pathological conditions. Here we report differential regulation of TAZ and YAP in response to oxidative stress. H2O2 exposure leads to increased stability and activation of TAZ but not of YAP. H2O2 induces reversible S-glutathionylation at conserved cysteine residues within TAZ. We further demonstrate that TAZ S-glutathionylation is critical for reactive oxygen species (ROS)-mediated, TAZ-dependent TEA domain transcription factor (TEAD) trans-activation. Lysophosphatidic acid, a physiological activator of YAP and TAZ, induces ROS elevation and, subsequently, TAZ S-glutathionylation, which promotes TAZ-mediated target gene expression. TAZ expression is essential for renal homeostasis in mice, and we identify basal TAZ S-glutathionylation in murine kidney lysates, which is elevated during ischemia/reperfusion injury in vivo This induced nuclear localization of TAZ and increased expression of connective tissue growth factor. These results describe a novel mechanism by which ROS sustains total cellular levels of TAZ. This preferential regulation suggests TAZ to be a redox sensor of the Hippo pathway.
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Affiliation(s)
- Rajesh Kumar Gandhirajan
- From the Department II of Internal Medicine and Center for Molecular Medicine, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and
| | - Manaswita Jain
- From the Department II of Internal Medicine and Center for Molecular Medicine, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and
| | - Benedikt Walla
- From the Department II of Internal Medicine and Center for Molecular Medicine, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and
| | - Marc Johnsen
- From the Department II of Internal Medicine and Center for Molecular Medicine, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and
| | - Malte P Bartram
- From the Department II of Internal Medicine and Center for Molecular Medicine, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and
| | - Minh Huynh Anh
- From the Department II of Internal Medicine and Center for Molecular Medicine, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and
| | - Markus M Rinschen
- From the Department II of Internal Medicine and Center for Molecular Medicine, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and
| | - Thomas Benzing
- From the Department II of Internal Medicine and Center for Molecular Medicine, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and Systems Biology of Ageing Cologne, University of Cologne, 50937 Cologne, Germany
| | - Bernhard Schermer
- From the Department II of Internal Medicine and Center for Molecular Medicine, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and Systems Biology of Ageing Cologne, University of Cologne, 50937 Cologne, Germany
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20
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Mayrhofer JM, Haiss F, Haenni D, Weber S, Zuend M, Barrett MJP, Ferrari KD, Maechler P, Saab AS, Stobart JL, Wyss MT, Johannssen H, Osswald H, Palmer LM, Revol V, Schuh CD, Urban C, Hall A, Larkum ME, Rutz-Innerhofer E, Zeilhofer HU, Ziegler U, Weber B. Design and performance of an ultra-flexible two-photon microscope for in vivo research. BIOMEDICAL OPTICS EXPRESS 2015; 6:4228-37. [PMID: 26600989 PMCID: PMC4646533 DOI: 10.1364/boe.6.004228] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 09/28/2015] [Accepted: 09/28/2015] [Indexed: 05/12/2023]
Abstract
We present a cost-effective in vivo two-photon microscope with a highly flexible frontend for in vivo research. Our design ensures fast and reproducible access to the area of interest, including rotation of imaging plane, and maximizes space for auxiliary experimental equipment in the vicinity of the animal. Mechanical flexibility is achieved with large motorized linear stages that move the objective in the X, Y, and Z directions up to 130 mm. 360° rotation of the frontend (rotational freedom for one axis) is achieved with the combination of a motorized high precision bearing and gearing. Additionally, the modular design of the frontend, based on commercially available optomechanical parts, allows straightforward updates to future scanning technologies. The design exceeds the mobility of previous movable microscope designs while maintaining high optical performance.
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Affiliation(s)
- Johannes M. Mayrhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Florent Haiss
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- IZKF Aachen, Medical Faculty of the RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
- Institute for Neuropathology, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Dominik Haenni
- Center for Microscopy and Image Analysis, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Stefan Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Matthew J. P. Barrett
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Philipp Maechler
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Aiman S. Saab
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Jillian L. Stobart
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Matthias T. Wyss
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Helge Johannssen
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Harald Osswald
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Lucy M. Palmer
- Florey Instittue, University of Melbourne, 30 Royal Parade, Melbourne, Victoria, 3010, Australia
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Vincent Revol
- CSEM Suisse d’Electronique et de Microtechnique, Technoparkstrasse 1, 8005 Zurich, Switzerland
| | - Claus-Dieter Schuh
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Claus Urban
- CSEM Suisse d’Electronique et de Microtechnique, Technoparkstrasse 1, 8005 Zurich, Switzerland
| | - Andrew Hall
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Matthew E. Larkum
- Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Edith Rutz-Innerhofer
- CSEM Suisse d’Electronique et de Microtechnique, Technoparkstrasse 1, 8005 Zurich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Urs Ziegler
- Center for Microscopy and Image Analysis, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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21
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Nagao Y, Kimura K, Wang S, Fujiwara T, Mizoguchi A. Real-time histological imaging of kidneys stained with food dyes using multiphoton microscopy. Microsc Res Tech 2015; 78:847-58. [DOI: 10.1002/jemt.22535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 06/01/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Yasuaki Nagao
- Department of Neural Regeneration and Cell Communication; Mie University Graduate School of Medicine; Tsu Japan
| | - Kazushi Kimura
- Department of Neural Regeneration and Cell Communication; Mie University Graduate School of Medicine; Tsu Japan
- Department of Physical Therapy Faculty of Human Science; Hokkaido Bunkyo University; Eniwa Japan
| | - Shujie Wang
- Department of Neural Regeneration and Cell Communication; Mie University Graduate School of Medicine; Tsu Japan
| | - Takeshi Fujiwara
- Department of Neural Regeneration and Cell Communication; Mie University Graduate School of Medicine; Tsu Japan
| | - Akira Mizoguchi
- Department of Neural Regeneration and Cell Communication; Mie University Graduate School of Medicine; Tsu Japan
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22
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Hall AM, Molitoris BA. Dynamic multiphoton microscopy: focusing light on acute kidney injury. Physiology (Bethesda) 2015; 29:334-42. [PMID: 25180263 DOI: 10.1152/physiol.00010.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Acute kidney injury (AKI) is a major global health problem; much research has been conducted on AKI, and numerous agents have shown benefit in animal studies, but none have translated into treatments. There is, therefore, a pressing unmet need to increase knowledge of the pathophysiology of AKI. Multiphoton microscopy (MPM) provides a tool to non-invasively visualize dynamic events in real time and at high resolution in rodent kidneys, and in this article we review its application to study novel mechanisms and treatments in different forms of AKI.
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Affiliation(s)
- Andrew M Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; and
| | - Bruce A Molitoris
- Indiana University School of Medicine, Indiana Center for Biological Microscopy, Indianapolis, Indiana
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23
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Novel in vivo techniques to visualize kidney anatomy and function. Kidney Int 2015; 88:44-51. [PMID: 25738253 PMCID: PMC4490063 DOI: 10.1038/ki.2015.65] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 01/05/2015] [Accepted: 01/06/2015] [Indexed: 12/11/2022]
Abstract
Intravital imaging using multiphoton microscopy (MPM) has become an increasingly popular and widely used experimental technique in kidney research over the past few years. MPM allows deep optical sectioning of the intact, living kidney tissue with submicron resolution which is unparalleled among intravital imaging approaches. MPM has solved a long-standing critical technical barrier in renal research to study several complex and inaccessible cell types and anatomical structures in vivo in their native environment. Comprehensive and quantitative kidney structure and function MPM studies helped our better understanding of the cellular and molecular mechanisms of the healthy and diseased kidney. This review summarizes recent in vivo MPM studies with a focus on the glomerulus and the filtration barrier, although select, glomerulus-related renal vascular and tubular functions are also mentioned. The latest applications of serial MPM of the same glomerulus in vivo, in the intact kidney over several days, during the progression of glomerular disease are discussed. This visual approach, in combination with genetically encoded fluorescent markers of cell lineage, has helped to track the fate and function (e.g. cell calcium changes) of single podocytes during the development of glomerular pathologies, and provided visual proof for the highly dynamic rather than static nature of the glomerular environment. Future intravital imaging applications have the promise to further push the limits of optical microscopy, and to advance our understanding of the mechanisms of kidney injury. Also, MPM will help to study new mechanisms of tissue repair and regeneration, a cutting edge area of kidney research.
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24
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Zorov DB, Juhaszova M, Sollott SJ. Mitochondrial reactive oxygen species (ROS) and ROS-induced ROS release. Physiol Rev 2014; 94:909-50. [PMID: 24987008 DOI: 10.1152/physrev.00026.2013] [Citation(s) in RCA: 3187] [Impact Index Per Article: 318.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Byproducts of normal mitochondrial metabolism and homeostasis include the buildup of potentially damaging levels of reactive oxygen species (ROS), Ca(2+), etc., which must be normalized. Evidence suggests that brief mitochondrial permeability transition pore (mPTP) openings play an important physiological role maintaining healthy mitochondria homeostasis. Adaptive and maladaptive responses to redox stress may involve mitochondrial channels such as mPTP and inner membrane anion channel (IMAC). Their activation causes intra- and intermitochondrial redox-environment changes leading to ROS release. This regenerative cycle of mitochondrial ROS formation and release was named ROS-induced ROS release (RIRR). Brief, reversible mPTP opening-associated ROS release apparently constitutes an adaptive housekeeping function by the timely release from mitochondria of accumulated potentially toxic levels of ROS (and Ca(2+)). At higher ROS levels, longer mPTP openings may release a ROS burst leading to destruction of mitochondria, and if propagated from mitochondrion to mitochondrion, of the cell itself. The destructive function of RIRR may serve a physiological role by removal of unwanted cells or damaged mitochondria, or cause the pathological elimination of vital and essential mitochondria and cells. The adaptive release of sufficient ROS into the vicinity of mitochondria may also activate local pools of redox-sensitive enzymes involved in protective signaling pathways that limit ischemic damage to mitochondria and cells in that area. Maladaptive mPTP- or IMAC-related RIRR may also be playing a role in aging. Because the mechanism of mitochondrial RIRR highlights the central role of mitochondria-formed ROS, we discuss all of the known ROS-producing sites (shown in vitro) and their relevance to the mitochondrial ROS production in vivo.
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Affiliation(s)
- Dmitry B Zorov
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; and Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Magdalena Juhaszova
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; and Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Steven J Sollott
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia; and Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
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25
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Small DM, Morais C, Coombes JS, Bennett NC, Johnson DW, Gobe GC. Oxidative stress-induced alterations in PPAR-γ and associated mitochondrial destabilization contribute to kidney cell apoptosis. Am J Physiol Renal Physiol 2014; 307:F814-22. [PMID: 25122050 DOI: 10.1152/ajprenal.00205.2014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The mechanism(s) underlying renoprotection by peroxisome proliferator-activated receptor (PPAR)-γ agonists in diabetic and nondiabetic kidney disease are not well understood. Mitochondrial dysfunction and oxidative stress contribute to kidney disease. PPAR-γ upregulates proteins required for mitochondrial biogenesis. Our aim was to determine whether PPAR-γ has a role in protecting the kidney proximal tubular epithelium (PTE) against mitochondrial destabilisation and oxidative stress. HK-2 PTE cells were subjected to oxidative stress (0.2-1.0 mM H₂O₂) for 2 and 18 h and compared with untreated cells for apoptosis, mitosis (morphology/biomarkers), cell viability (MTT), superoxide (dihydroethidium), mitochondrial function (MitoTracker red and JC-1), ATP (luminescence), and mitochondrial ultrastructure. PPAR-γ, phospho-PPAR-γ, PPAR-γ coactivator (PGC)-1α, Parkin (Park2), p62, and light chain (LC)3β were investigated using Western blots. PPAR-γ was modulated using the agonists rosiglitazone, pioglitazone, and troglitazone. Mitochondrial destabilization increased with H₂O₂concentration, ATP decreased (2 and 18 h; P < 0.05), Mitotracker red and JC-1 fluorescence indicated loss of mitochondrial membrane potential, and superoxide increased (18 h, P < 0.05). Electron microscopy indicated sparse mitochondria, with disrupted cristae. Mitophagy was evident at 2 h (Park2 and LC3β increased; p62 decreased). Impaired mitophagy was indicated by p62 accumulation at 18 h (P < 0.05). PPAR-γ expression decreased, phospho-PPAR-γ increased, and PGC-1α decreased (2 h), indicating aberrant PPAR-γ activation and reduced mitochondrial biogenesis. Cell viability decreased (2 and 18 h, P < 0.05). PPAR-γ agonists promoted further apoptosis. In summary, oxidative stress promoted mitochondrial destabilisation in kidney PTE, in association with increased PPAR-γ phosphorylation. PPAR-γ agonists failed to protect PTE. Despite positive effects in other tissues, PPAR-γ activation appears to be detrimental to kidney PTE health when oxidative stress induces damage.
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Affiliation(s)
- David M Small
- Centre for Kidney Disease Research, School of Medicine, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Christudas Morais
- Centre for Kidney Disease Research, School of Medicine, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Jeff S Coombes
- Centre for Kidney Disease Research, School of Medicine, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia; School of Human Movement Studies, The University of Queensland, Brisbane, Queensland, Australia
| | - Nigel C Bennett
- Centre for Kidney Disease Research, School of Medicine, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia; UQ Centre for Clinical Research, The University of Queensland, Brisbane, Queensland, Australia; and
| | - David W Johnson
- Centre for Kidney Disease Research, School of Medicine, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia; Department of Nephrology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
| | - Glenda C Gobe
- Centre for Kidney Disease Research, School of Medicine, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia;
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26
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The cyclin-dependent kinase inhibitor p21 is essential for the beneficial effects of renal ischemic preconditioning on renal ischemia/reperfusion injury in mice. Kidney Int 2014; 85:871-9. [DOI: 10.1038/ki.2013.496] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 07/23/2013] [Accepted: 08/22/2013] [Indexed: 01/02/2023]
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27
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Bruinsma BG, Yarmush ML, Uygun K. Organomatics and organometrics: Novel platforms for long-term whole-organ culture. TECHNOLOGY 2014; 2:13. [PMID: 25035864 PMCID: PMC4097862 DOI: 10.1142/s2339547814300029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Organ culture systems are instrumental as experimental whole-organ models of physiology and disease, as well as preservation modalities facilitating organ replacement therapies such as transplantation. Nevertheless, a coordinated system of machine perfusion components and integrated regulatory control has yet to be fully developed to achieve long-term maintenance of organ function ex vivo. Here we outline current strategies for organ culture, or organomatics, and how these systems can be regulated by means of computational algorithms, or organometrics, to achieve the organ culture platforms anticipated in modern-day biomedicine.
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28
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Stokman G, Qin Y, Booij TH, Ramaiahgari S, Lacombe M, Dolman MEM, van Dorenmalen KMA, Teske GJD, Florquin S, Schwede F, van de Water B, Kok RJ, Price LS. Epac-Rap signaling reduces oxidative stress in the tubular epithelium. J Am Soc Nephrol 2014; 25:1474-85. [PMID: 24511123 DOI: 10.1681/asn.2013070679] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Activation of Rap1 by exchange protein activated by cAMP (Epac) promotes cell adhesion and actin cytoskeletal polarization. Pharmacologic activation of Epac-Rap signaling by the Epac-selective cAMP analog 8-pCPT-2'-O-Me-cAMP during ischemia-reperfusion (IR) injury reduces renal failure and application of 8-pCPT-2'-O-Me-cAMP promotes renal cell survival during exposure to the nephrotoxicant cisplatin. Here, we found that activation of Epac by 8-pCPT-2'-O-Me-cAMP reduced production of reactive oxygen species during reoxygenation after hypoxia by decreasing mitochondrial superoxide production. Epac activation prevented disruption of tubular morphology during diethyl maleate-induced oxidative stress in an organotypic three-dimensional culture assay. In vivo renal targeting of 8-pCPT-2'-O-Me-cAMP to proximal tubules using a kidney-selective drug carrier approach resulted in prolonged activation of Rap1 compared with nonconjugated 8-pCPT-2'-O-Me-cAMP. Activation of Epac reduced antioxidant signaling during IR injury and prevented tubular epithelial injury, apoptosis, and renal failure. Our data suggest that Epac1 decreases reactive oxygen species production by preventing mitochondrial superoxide formation during IR injury, thus limiting the degree of oxidative stress. These findings indicate a new role for activation of Epac as a therapeutic application in renal injury associated with oxidative stress.
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Affiliation(s)
- Geurt Stokman
- Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden, The Netherlands;
| | - Yu Qin
- Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden, The Netherlands
| | - Tijmen H Booij
- Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden, The Netherlands
| | - Sreenivasa Ramaiahgari
- Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden, The Netherlands
| | | | - M Emmy M Dolman
- Department of Pharmaceutics, Utrecht University, Utrecht, The Netherlands
| | | | | | - Sandrine Florquin
- Department of Pathology, Academic Medical Center, Amsterdam, The Netherlands
| | | | - Bob van de Water
- Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden, The Netherlands
| | - Robbert J Kok
- Department of Pharmaceutics, Utrecht University, Utrecht, The Netherlands
| | - Leo S Price
- Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden, The Netherlands; OcellO BV, Leiden, The Netherlands
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30
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Cassini MF, da Costa MM, Bagnato VS, Tirapelli LF, Silva GEB, Molina CAF, Martins ACP, Tucci S. Fluorescence spectroscopy in renal ischemia and reperfusion: noninvasive evaluation of organ viability. Transplant Proc 2013; 45:1715-9. [PMID: 23769030 DOI: 10.1016/j.transproceed.2012.10.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Accepted: 10/30/2012] [Indexed: 11/25/2022]
Abstract
BACKGROUND Damage provoked by ischemia in renal transplants is difficult to quantify. To determine whether a donated organ is fit for transplantation. We sought to correlate the findings of fluorescence spectroscopy (FS) with histologic evidence of ischemic injury and organ viability. METHODS Kidneys of 33 rats were submitted to FS of the upper and lower poles as well as the middle third. Excitation was generated by the laser's wavelengths of 408, 442, and 532 nm. Rats were randomized into groups with the 30, 60, and 120 minutes warm ischemia before analysis by FS, that was repeated at 5 minutes after reperfusion. RESULTS FS results in the reperfusion phase correlated with ischemia time and degree of histologic injury. After 60 or 120 minutes of ischemia, the excitation lasers of 532 and 442 nm resented a significant negative correlation coefficient with the histological grade (r = -0.61 and r = -0.73, respectively). CONCLUSIONS There was a strong correlation between FS and histologic changes only in the reperfusion phase after renal ischemia. The method was thus unable to assess the viability of organs before transplantation.
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Affiliation(s)
- M F Cassini
- Division of Urology, Department of Surgery and Anatomy, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil.
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Hall AM, Rhodes GJ, Sandoval RM, Corridon PR, Molitoris BA. In vivo multiphoton imaging of mitochondrial structure and function during acute kidney injury. Kidney Int 2013; 83:72-83. [PMID: 22992467 PMCID: PMC4136483 DOI: 10.1038/ki.2012.328] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mitochondrial dysfunction has been implicated in the pathogenesis of acute kidney injury due to ischemia and toxic drugs. Methods for imaging mitochondrial function in cells using confocal microscopy are well established; more recently, it was shown that these techniques can be utilized in ex vivo kidney tissue using multiphoton microscopy. We extended this approach in vivo and found that kidney mitochondrial structure and function can be imaged in anesthetized rodents using multiphoton excitation of endogenous and exogenous fluorophores. Mitochondrial nicotinamide adenine dinucleotide increased markedly in rat kidneys in response to ischemia. Following intravenous injection, the mitochondrial membrane potential-dependent dye TMRM was taken up by proximal tubules; in response to ischemia, the membrane potential dissipated rapidly and mitochondria became shortened and fragmented in proximal tubules. In contrast, the mitochondrial membrane potential and structure were better maintained in distal tubules. Changes in mitochondrial structure, nicotinamide adenine dinucleotide, and membrane potential were found in the proximal, but not distal, tubules after gentamicin exposure. These changes were sporadic, highly variable among animals, and were preceded by changes in non-mitochondrial structures. Thus, real-time changes in mitochondrial structure and function can be imaged in rodent kidneys in vivo using multiphoton excitation of endogenous and exogenous fluorophores in response to ischemia-reperfusion injury or drug toxicity.
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MESH Headings
- Acute Kidney Injury/etiology
- Acute Kidney Injury/pathology
- Acute Kidney Injury/physiopathology
- Animals
- Gentamicins/adverse effects
- Glutathione/metabolism
- Ischemia/complications
- Kidney/blood supply
- Kidney Tubules, Distal/metabolism
- Kidney Tubules, Distal/pathology
- Kidney Tubules, Distal/physiopathology
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/pathology
- Kidney Tubules, Proximal/physiopathology
- Male
- Membrane Potential, Mitochondrial/physiology
- Mice
- Mice, Inbred C57BL
- Microscopy, Fluorescence, Multiphoton/methods
- Mitochondria/pathology
- Mitochondria/physiology
- NAD/metabolism
- Rats
- Rats, Sprague-Dawley
- Rats, Wistar
- Reactive Oxygen Species/metabolism
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Affiliation(s)
- Andrew M Hall
- University College London Centre for Nephrology, Royal Free Hospital, London, UK.
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Peppiatt-Wildman CM, Crawford C, Hall AM. Fluorescence imaging of intracellular calcium signals in intact kidney tissue. Nephron Clin Pract 2012; 121:e49-58. [PMID: 23147410 DOI: 10.1159/000342812] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 08/14/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Intracellular calcium (Ca(2+)) plays an important role in normal renal physiology and in the pathogenesis of various kidney diseases; however, the study of Ca(2+) signals in intact tissue has been limited by technical difficulties, including achieving adequate loading of Ca(2+)-sensitive fluorescent dyes. The kidney slice preparation represents a model whereby three-dimensional tissue architecture is preserved and structures in both the cortex and medulla can be imaged using confocal or multiphoton microscopy. METHODS Ca(2+)-sensitive dyes Rhod-2, Fura-red and Fluo-4 were loaded into tubular and vascular cells in rat kidney slices using a re-circulating perfusion system and real-time imaging of Ca(2+) signals was recorded by confocal microscopy. Kidney slices were also obtained from transgenic mice expressing the GCaMP2 Ca(2+)-sensor in their endothelial cells and real time Ca(2+) transients stimulated by physiological stimuli. RESULTS Wide spread loading of Ca(2+) indicators was achieved in the tubular and vascular structures of both the medulla and cortex. Real time Ca(2+) signals were successfully recorded in different intracellular compartments of both rat and mouse cortical and medullary tubules in response to physiological stimuli (ATP and angiotensin II). Glomerular Ca(2+) transients were similarly recorded in kidney slices taken from the transgenic mouse expressing the GCaMP2 Ca(2+)-sensor. CONCLUSION We present new approaches that can be adopted to image cytosolic and mitochondrial Ca(2+) signals within various cell types in intact kidney tissue. Moreover, techniques described in this study can be used to facilitate future detailed investigations of intracellular Ca(2+) homeostasis in renal health and disease.
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Affiliation(s)
- C M Peppiatt-Wildman
- Medway School of Pharmacy, The Universities of Kent and Greenwich at Medway, Chatham Maritime, UK. C.M.Peppiatt @ kent.ac.uk
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Towner RA, Smith N, Saunders D, Henderson M, Downum K, Lupu F, Silasi-Mansat R, Ramirez DC, Gomez-Mejiba SE, Bonini MG, Ehrenshaft M, Mason RP. In vivo imaging of immuno-spin trapped radicals with molecular magnetic resonance imaging in a diabetic mouse model. Diabetes 2012; 61:2405-13. [PMID: 22698922 PMCID: PMC3447912 DOI: 10.2337/db11-1540] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 04/05/2012] [Indexed: 01/08/2023]
Abstract
Oxidative stress plays a major role in diabetes. In vivo levels of membrane-bound radicals (MBRs) in a streptozotocin-induced diabetic mouse model were uniquely detected by combining molecular magnetic resonance imaging (mMRI) and immunotrapping techniques. An anti-DMPO (5,5-dimethyl-1-pyrroline N-oxide) antibody (Ab) covalently bound to an albumin (BSA)-Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)-biotin MRI contrast agent (anti-DMPO probe), and mMRI, were used to detect in vivo levels of DMPO-MBR adducts in kidneys, livers, and lungs of diabetic mice, after DMPO administration. Magnetic resonance signal intensities, which increase in the presence of a Gd-based molecular probe, were significantly higher within the livers, kidneys, and lungs of diabetic animals administered the anti-DMPO probe compared with controls. Fluorescence images validated the location of the anti-DMPO probe in excised tissues via conjugation of streptavidin-Cy3, which targeted the probe biotin moiety, and immunohistochemistry was used to validate the presence of DMPO adducts in diabetic mouse livers. This is the first report of noninvasively imaging in vivo levels of MBRs within any disease model. This method can be specifically applied toward diabetes models for in vivo assessment of free radical levels, providing an avenue to more fully understand the role of free radicals in diabetes.
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Affiliation(s)
- Rheal A Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA.
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Crawford C, Hall AM, Peppiatt-Wildman CM. Imaging intracellular calcium signals in intact kidney tissue. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.690.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Carol Crawford
- Urinary System Physiology UnitRoyal Veterinary CollegeLondonUnited Kingdom
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Peti-Peterdi J, Burford JL, Hackl MJ. The first decade of using multiphoton microscopy for high-power kidney imaging. Am J Physiol Renal Physiol 2011; 302:F227-33. [PMID: 22031850 DOI: 10.1152/ajprenal.00561.2011] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In this review, we highlight the major scientific breakthroughs in kidney research achieved using multiphoton microscopy (MPM) and summarize the milestones in the technological development of kidney MPM during the past 10 years. Since more and more renal laboratories invest in MPM worldwide, we discuss future directions and provide practical, useful tips and examples for the application of this still-emerging optical sectioning technology. Advantages of using MPM in various kidney preparations that range from freshly dissected individual glomeruli or the whole kidney in vitro to MPM of the intact mouse and rat kidney in vivo are reviewed. Potential combinations of MPM with micromanipulation techniques including microperfusion and micropuncture are also included. However, we emphasize the most advanced and complex, quantitative in vivo imaging applications as the ultimate use of MPM since the true mandate of this technology is to look inside intact organs in live animals and humans.
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Affiliation(s)
- János Peti-Peterdi
- Departments of Physiology and Biophysics, and Medicine, Zilkha Neurogenetic Institute, Univ. of Southern California, Los Angeles, CA 90033, USA.
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