Browsing by Author "Jones, Bryce A."

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    Characterization of the Ocular Phenotype in a Col4a3 Knockout Mouse Model of Alport Syndrome
    (Association for Research in Vision and Ophthalmology, 2024) Belamkar, Ameya; Luo, Qianyi; Mahajan, Neha; Abhyankar, Surabhi; Jones, Bryce A.; Sodhi, Rupinder Kaur; Pattabiraman, Padmanabhan P.; Levi, Moshe; Bhatwadekar, Ashay D.; Ophthalmology, School of Medicine
    Purpose: Alport syndrome (AS) is a genetic condition caused by a dysfunctional collagen (IV) α3α4α5 heterotrimer, leading to basement membrane instability and, ultimately, abnormalities in the kidney, inner ear, and eyes. This study aimed to characterize ocular pathology of AS by focusing on inflammatory and fibrotic markers. Methods: Col4a3tm1Dec knockout (KO) mice eyes were evaluated for the localization of collagen (IV) α3 and collagen (IV) α4, then stained for transforming growth factor-β1 (TGF-β1), TGF-β2, connective tissue growth factor (CTGF), and β-catenin. mRNA levels of the profibrotic genes S100a4, Acta2, Col1a1, Snai1, Snai2, and Twist1 were assessed using real-time reverse transcription quantitative PCR (RT-qPCR). Results: Collagen (IV) α3 and collagen (IV) α4 were co-expressed in Descemet's and Bruch's membrane but not in the retina, lens, or other corneal substructures. Immunofluorescence quantitation revealed upregulation of TGF-β1 in the anterior lens and TGF-β2 in the retina of KO eyes. Conversely, CTGF and β-catenin were shown to be elevated in the corneal epithelium but not the retina or lens. RT-qPCR showed an increase in the transcription of Acta2, Col1a1, and Snai2 in the retinas and Snai2 in anterior segments of KO mice. Conclusions: Col4a3 KO mice exhibited a differential inflammatory and profibrotic response in the cornea, retina, and lens, which may play a role in the ocular pathology of AS.
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    NAD+ prevents chronic kidney disease by activating renal tubular metabolism
    (American Society for Clinical Investigation, 2025-03-10) Jones, Bryce A.; Gisch, Debora L.; Myakala, Komuraiah; Sadiq, Amber; Cheng, Ying-Hua; Taranenko, Elizaveta; Panov, Julia; Korolowicz, Kyle; Ferreira, Ricardo Melo; Yang, Xiaoping; Santo, Briana A.; Allen, Katherine C.; Yoshida, Teruhiko; Wang, Xiaoxin X.; Rosenberg, Avi Z.; Jain, Sanjay; Eadon, Michael T.; Levi, Moshe; Medicine, School of Medicine
    Chronic kidney disease (CKD) is associated with renal metabolic disturbances, including impaired fatty acid oxidation (FAO). Nicotinamide adenine dinucleotide (NAD+) is a small molecule that participates in hundreds of metabolism-related reactions. NAD+ levels are decreased in CKD, and NAD+ supplementation is protective. However, both the mechanism of how NAD+ supplementation protects from CKD, as well as the cell types involved, are poorly understood. Using a mouse model of Alport syndrome, we show that nicotinamide riboside (NR), an NAD+ precursor, stimulated renal PPARα signaling and restored FAO in the proximal tubules, thereby protecting from CKD in both sexes. Bulk RNA-sequencing showed that renal metabolic pathways were impaired in Alport mice and activated by NR in both sexes. These transcriptional changes were confirmed by orthogonal imaging techniques and biochemical assays. Single-nuclei RNA sequencing and spatial transcriptomics, both the first of their kind to our knowledge from Alport mice, showed that NAD+ supplementation restored FAO in proximal tubule cells. Finally, we also report, for the first time to our knowledge, sex differences at the transcriptional level in this Alport model. In summary, the data herein identify a nephroprotective mechanism of NAD+ supplementation in CKD, and they demonstrate that this benefit localizes to the proximal tubule cells.