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Akansha Jain_Thesis_04_10_243.85 MB
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Dissertation
Functional studies of novel airway ciliated cell proteins in health and disease
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Spring 2025
DOI: 10.25820/etd.007879
Abstract
This thesis is an exploration into the function of uncoupling proteins and the role of a sensory cilia protein, RPGRIP1L, in airway ciliated cells. Ciliated cells of the airway require significant ATP to carry out ciliary beating. In addition, the airway epithelium is exposed to one of the highest oxygen levels in the body. Although ciliated cells have a clever supply chain where the producers (mitochondria) are bunched up right below the users (cilia), this strategy makes ciliated cells hotspots for ROS damage; this is worsened by their high O2 surrounding. In chapter two, we show that airway ciliated cells express uncoupling protein 2 (UCP2) and uncoupling protein 5 (UCP5). We show increased mitochondrial uncoupling through UCP2 and UCP5 decreases ROS generation and downstream toxicity in ciliated cells. One disease with impairment in ciliated cell function is primary ciliary dyskinesia. In chapter three, we describe the case of a 52-year-old man with suspected PCD. However, he had normal nasal nitric oxide (nNO) levels and no variants in known PCD associated genes. Additional testing identified two in cis variants in the RPGRIP1L gene. To study whether this gene might be associated with PCD, we used nasal epithelial cultures. RPGRIP1Lmut epithelia showed complete abolishment of mucociliary transport (MCT) and cilia beat frequency was decreased by only 30%. However scanning electron microscopy revealed a chaotic cilia arrangement on the airway surface. The basal feet in RPGRIP1Lmut epithelia were misaligned compared to control (circular standard deviations: control= 25.4 and RPGRIP1Lmut= 59.3). To further assess the contribution of RPGRIP1L, we quantified protein through immunofluorescence microscopy and found that it was significantly decreased compared to control epithelia. For this patient, the results show that he has PCD, which explains his clinical manifestations.
Details
- Title: Subtitle
- Functional studies of novel airway ciliated cell proteins in health and disease
- Creators
- Akansha Jain
- Contributors
- Michael J Welsh (Advisor)Michael G Anderson (Committee Member)Stefan Strack (Committee Member)Eric B Taylor (Committee Member)Daniel L Weeks (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Biomedical Science (Molecular Physiology and Biophysics)
- Date degree season
- Spring 2025
- DOI
- 10.25820/etd.007879
- Publisher
- University of Iowa
- Number of pages
- xii, 117 pages
- Copyright
- Copyright 2023 Akansha Jain
- Comment
- This thesis has been optimized for improved web viewing. If you require the original version, contact the University Archives at the University of Iowa: https://www.lib.uiowa.edu/sc/contact/
- Language
- English
- Date submitted
- 03/24/2024
- Description illustrations
- illustrations, graphs
- Description bibliographic
- Includes bibliographical references (pages 103-117).
- Public Abstract (ETD)
- Epithelia lining the respiratory airways provide the first line of defense for the lung. Goblet cells secrete mucus that traps inhaled pathogens and particulate material, and ciliated cells propel the mucus out of the lung by mucociliary transport. Dynein motor proteins are distributed along the length of cilia microtubules and powered by ATP hydrolysis drive cilia beating. Mitochondria are the major source of ATP that powers cilia. The early days of electron microscopy revealed that mitochondria cluster just beneath the apical cell membrane and its protruding cilia. This location suggested that ciliated airway epithelial cells solve the challenge of supplying ATP for cilia by bunching mitochondria nearby. However, the mitochondrial ETC is not entirely efficient due to electron leakage. Uncoupling proteins counteract O2− production by creating a proton leak pathway across the inner mitochondrial membrane that partially dissipates the electrochemical gradient. Our results indicate that UCP2 and UCP5 serve that function in ciliated airway epithelial cells; UCP2 and UCP5 decrease mitochondrial membrane potential, increase the fraction of mitochondrial respiration that is uncoupled from ATP production, and decrease the generation of ROS. The implications of studying basic biology of ciliated cells provides a better understanding when these systems break down. For example, primary ciliary dyskinesia is a disease that results from disrupted cilia function. We also explore how a sensory cilia gene is associated with primary ciliary dyskinesia.
- Academic Unit
- Biomedical Science Program
- Record Identifier
- 9984831125902771
Metrics
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