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Khattri RB, Louis LZ, Kim K, Anderson EM, Fazzone B, Harland KC, Hu Q, O'Malley KA, Berceli SA, Wymer J, Ryan TE, Scali ST. Temporal serum metabolomic and lipidomic analyses distinguish patients with access-related hand disability following arteriovenous fistula creation. Sci Rep 2023; 13:16811. [PMID: 37798334 PMCID: PMC10555997 DOI: 10.1038/s41598-023-43664-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 09/27/2023] [Indexed: 10/07/2023] Open
Abstract
For end-stage kidney disease (ESKD) patients, hemodialysis requires durable vascular access which is often surgically created using an arteriovenous fistula (AVF). However, some ESKD patients that undergo AVF placement develop access-related hand dysfunction (ARHD) through unknown mechanisms. In this study, we sought to determine if changes in the serum metabolome could distinguish ESKD patients that develop ARHD from those that have normal hand function following AVF creation. Forty-five ESKD patients that underwent first-time AVF creation were included in this study. Blood samples were obtained pre-operatively and 6-weeks post-operatively and metabolites were extracted and analyzed using nuclear magnetic resonance spectroscopy. Patients underwent thorough examination of hand function at both timepoints using the following assessments: grip strength manometry, dexterity, sensation, motor and sensory nerve conduction testing, hemodynamics, and the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. Nineteen of the forty-five patients displayed overt weakness using grip strength manometry (P < 0.0001). Unfortunately, the serum metabolome was indistinguishable between patients with and without weakness following AVF surgery. However, a significant correlation was found between the change in tryptophan levels and the change in grip strength suggesting a possible role of tryptophan-derived uremic metabolites in post-AVF hand-associated weakness. Compared to grip strength, changes in dexterity and sensation were smaller than those observed in grip strength, however, post-operative decreases in phenylalanine, glycine, and alanine were unique to patients that developed signs of motor or sensory disability following AVF creation.
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Affiliation(s)
- Ram B Khattri
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA
| | - Lauryn Z Louis
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA
| | - Kyoungrae Kim
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA
| | - Erik M Anderson
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, 32611, USA
- Malcom Randall Veteran Affairs Medical Center, Gainesville, FL, USA
| | - Brian Fazzone
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, 32611, USA
- Malcom Randall Veteran Affairs Medical Center, Gainesville, FL, USA
| | - Kenneth C Harland
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, 32611, USA
- Malcom Randall Veteran Affairs Medical Center, Gainesville, FL, USA
| | - Qiongyao Hu
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, 32611, USA
- Malcom Randall Veteran Affairs Medical Center, Gainesville, FL, USA
| | - Kerri A O'Malley
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, 32611, USA
- Malcom Randall Veteran Affairs Medical Center, Gainesville, FL, USA
| | - Scott A Berceli
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, 32611, USA
- Malcom Randall Veteran Affairs Medical Center, Gainesville, FL, USA
| | - James Wymer
- Department of Neurology, University of Florida, Gainesville, FL, 32611, USA
| | - Terence E Ryan
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, 32611, USA
- Center for Exercise Science, University of Florida, Gainesville, FL, 32611, USA
| | - Salvatore T Scali
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, 32611, USA.
- Malcom Randall Veteran Affairs Medical Center, Gainesville, FL, USA.
- , Gainesville, USA.
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Frost CJ, Ramirez-Mata A, Khattri RB, Merritt ME, Frost SC. Effects of β-caryophyllene and oxygen availability on cholesterol and fatty acids in breast cancer cells. PLoS One 2023; 18:e0281396. [PMID: 36893152 PMCID: PMC9997903 DOI: 10.1371/journal.pone.0281396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 01/21/2023] [Indexed: 03/10/2023] Open
Abstract
Hypoxia is a common feature of most solid tumors, one that favors tumor progression and limits treatment effectiveness. Targeting hypoxia has long been a goal in cancer therapy, by identifying factors that reverse or ameliorate the effects of hypoxia on cancer cells. We, and others, have shown that β-caryophyllene (BCP) exhibits anti-proliferative properties in cancer cells. We have further shown that non-cytotoxic concentrations of BCP affect cholesterol and lipid biosynthesis in hypoxic hBrC cells at both transcriptional and translational levels. This led us to hypothesize that BCP may reverse the hypoxic phenotype in hBrC cells. To test this, we determined the effect of BCP on hypoxic sensitive pathways, including oxygen consumption, glycolysis, oxidative stress, cholesterol and fatty acid biosynthesis, and ERK activation. While each of these studies revealed new information on the regulation by hypoxia and BCP, only the lipidomic studies showed reversal of hypoxic-dependent effects by BCP. These later studies showed that hypoxia-treated samples lowered monounsaturated fatty acid levels, shifting the saturation ratios of the fatty acid pools. This signature was ameliorated by sub-lethal concentrations of BCP, possibly through an effect on the C:16 fatty acid saturation ratios. This is consistent with BCP-induced upregulation of the stearoyl-CoA desaturase (SCD) gene, observed previously. This suggests that BCP may interfere with the lipid signature modulated by hypoxia which could have consequences for membrane biosynthesis or composition, both of which are important for cell replication.
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Affiliation(s)
- Christopher J. Frost
- BIO5 Institute, University of Arizona, Tucson, AZ, United States of America
- Department of Biology, University of Louisville, Louisville, KY, United States of America
| | - Andrea Ramirez-Mata
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States of America
| | - Ram B. Khattri
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States of America
| | - Matthew E. Merritt
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States of America
| | - Susan C. Frost
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States of America
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Khattri RB, Batra A, Matheny M, Hart C, Henley-Beasley SC, Hammers D, Zeng H, White Z, Ryan TE, Barton E, Pascal B, Walter GA. Magnetic resonance quantification of skeletal muscle lipid infiltration in a humanized mouse model of Duchenne muscular dystrophy. NMR Biomed 2023; 36:e4869. [PMID: 36331178 PMCID: PMC10308798 DOI: 10.1002/nbm.4869] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/28/2022] [Accepted: 11/02/2022] [Indexed: 06/16/2023]
Abstract
Rodent models of Duchenne muscular dystrophy (DMD) often do not recapitulate the severity of muscle wasting and resultant fibro-fatty infiltration observed in DMD patients. Having recently documented severe muscle wasting and fatty deposition in two preclinical models of muscular dystrophy (Dysferlin-null and mdx mice) through apolipoprotein E (ApoE) gene deletion without and with cholesterol-, triglyceride-rich Western diet supplementation, we sought to determine whether magnetic resonance imaging and spectroscopy (MRI and MRS, respectively) could be used to detect, characterize, and compare lipid deposition in mdx-ApoE knockout with mdx mice in a diet-dependent manner. MRI revealed that both mdx and mdx-ApoE mice exhibited elevated proton relaxation time constants (T2 ) in their lower hindlimbs irrespective of diet, indicating both chronic muscle damage and fatty tissue deposition. The mdx-ApoE mice on a Western diet (mdx-ApoEW ) presented with greatest fatty tissue infiltration in the posterior compartment of the hindlimb compared with other groups, as detected by MRI/MRS. High-resolution magic angle spinning confirmed elevated lipid deposition in the posterior compartments of mdx-ApoEW mice in vivo and ex vivo, respectively. In conclusion, the mdx-ApoEW model recapitulates some of the extreme fatty tissue deposition observed clinically in DMD muscle but typically absent in mdx mice. This preclinical model will help facilitate the development of new imaging modalities directly relevant to the image contrast generated in DMD, and help to refine MR-based biomarkers and their relationship to tissue structure and disease progression.
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Affiliation(s)
- Ram B. Khattri
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Abhinandan Batra
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA
| | - Michael Matheny
- Department of Pharmacology & Therapeutics, University of Florida, Gainesville, FL, USA
| | - Cora Hart
- Department of Pharmacology & Therapeutics, University of Florida, Gainesville, FL, USA
| | | | - David Hammers
- Department of Pharmacology & Therapeutics, University of Florida, Gainesville, FL, USA
| | - Huadong Zeng
- Advanced Magnetic Resonance Imaging and Spectroscopy Facility, University of Florida, Gainesville, FL, USA
| | - Zoe White
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Canada
| | - Terence E. Ryan
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
- Center of Exercise Science, University of Florida, Gainesville, FL, United States
| | - Elisabeth Barton
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Bernatchez Pascal
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Canada
| | - Glenn A. Walter
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA
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Khattri RB, Puglise J, Ryan TE, Walter GA, Merritt ME, Barton ER. Isolated murine skeletal muscles utilize pyruvate over glucose for oxidation. Metabolomics 2022; 18:105. [PMID: 36480060 PMCID: PMC9732067 DOI: 10.1007/s11306-022-01948-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 10/29/2022] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Fuel sources for skeletal muscle tissue include carbohydrates and fatty acids, and utilization depends upon fiber type, workload, and substrate availability. The use of isotopically labeled substrate tracers combined with nuclear magnetic resonance (NMR) enables a deeper examination of not only utilization of substrates by a given tissue, but also their contribution to tricarboxylic acid (TCA) cycle intermediates. OBJECTIVES The goal of this study was to determine the differential utilization of substrates in isolated murine skeletal muscle, and to evaluate how isopotomer anlaysis provided insight into skeletal muscle metabolism. METHODS Isolated C57BL/6 mouse hind limb muscles were incubated in oxygenated solution containing uniformly labeled 13C6 glucose, 13C3 pyruvate, or 13C2 acetate at room temperature. Isotopomer analysis of 13C labeled glutamate was performed on pooled extracts of isolated soleus and extensor digitorum longus (EDL) muscles. RESULTS Pyruvate and acetate were more avidly consumed than glucose with resultant increases in glutamate labeling in both muscle groups. Glucose incubation resulted in glutamate labeling, but with high anaplerotic flux in contrast to the labeling by pyruvate. Muscle fiber type distinctions were evident by differences in lactate enrichment and extent of substrate oxidation. CONCLUSION Isotope tracing experiments in isolated muscles reveal that pyruvate and acetate are avidly oxidized by isolated soleus and EDL muscles, whereas glucose labeling of glutamate is accompanied by high anaplerotic flux. We believe our results may set the stage for future examination of metabolic signatures of skeletal muscles from pre-clinical models of aging, type-2 diabetes and neuromuscular disease.
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Affiliation(s)
- Ram B Khattri
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance, University of Florida, 124 Florida Gym, 1864 Stadium Road, Gainesville, FL, 32611, USA
| | - Jason Puglise
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance, University of Florida, 124 Florida Gym, 1864 Stadium Road, Gainesville, FL, 32611, USA
| | - Terence E Ryan
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance, University of Florida, 124 Florida Gym, 1864 Stadium Road, Gainesville, FL, 32611, USA
- Myology Institute, University of Florida, Gainesville, USA
- Center for Exercise Science, University of Florida, Gainesville, FL, USA
| | - Glenn A Walter
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, USA
- Myology Institute, University of Florida, Gainesville, USA
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, USA
| | - Elisabeth R Barton
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance, University of Florida, 124 Florida Gym, 1864 Stadium Road, Gainesville, FL, 32611, USA.
- Myology Institute, University of Florida, Gainesville, USA.
- Center for Exercise Science, University of Florida, Gainesville, FL, USA.
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Khattri RB, Kim K, Anderson EM, Fazzone B, Harland KC, Hu Q, Palzkill VR, Cort TA, O'Malley KA, Berceli SA, Scali ST, Ryan TE. Metabolomic profiling reveals muscle metabolic changes following iliac arteriovenous fistula creation in mice. Am J Physiol Renal Physiol 2022; 323:F577-F589. [PMID: 36007889 PMCID: PMC9602894 DOI: 10.1152/ajprenal.00156.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/22/2022] [Accepted: 08/22/2022] [Indexed: 12/31/2022] Open
Abstract
End-stage kidney disease, the most advanced stage of chronic kidney disease (CKD), requires renal replacement therapy or kidney transplant to sustain life. To accomplish durable dialysis access, the creation of an arteriovenous fistula (AVF) has emerged as a preferred approach. Unfortunately, a significant proportion of patients that receive an AVF experience some form of hand dysfunction; however, the mechanisms underlying these side effects are not understood. In this study, we used nuclear magnetic resonance spectroscopy to investigate the muscle metabolome following iliac AVF placement in mice with CKD. To induce CKD, C57BL6J mice were fed an adenine-supplemented diet for 3 wk and then randomized to receive AVF or sham surgery. Two weeks following surgery, the quadriceps muscles were rapidly dissected and snap frozen for metabolite extraction and subsequent nuclear magnetic resonance analysis. Principal component analysis demonstrated clear separation between groups, confirming a unique metabolome in mice that received an AVF. AVF creation resulted in reduced levels of creatine, ATP, and AMP as well as increased levels of IMP and several tricarboxylic acid cycle metabolites suggesting profound energetic stress. Pearson correlation and multiple linear regression analyses identified several metabolites that were strongly linked to measures of limb function (grip strength, gait speed, and mitochondrial respiration). In summary, AVF creation generates a unique metabolome profile in the distal skeletal muscle indicative of an energetic crisis and myosteatosis.NEW & NOTEWORTHY Creation of an arteriovenous fistula (AVF) is the preferred approach for dialysis access, but some patients experience hand dysfunction after AVF creation. In this study, we provide a detailed metabolomic analysis of the limb muscle in a murine model of AVF. AVF creation resulted in metabolite changes associated with an energetic crisis and myosteatosis that associated with limb function.
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Affiliation(s)
- Ram B Khattri
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Kyoungrae Kim
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Erik M Anderson
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, Florida
- Malcom Randall Veterans Affairs Medical Center, Gainesville, Florida
| | - Brian Fazzone
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, Florida
- Malcom Randall Veterans Affairs Medical Center, Gainesville, Florida
| | - Kenneth C Harland
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, Florida
- Malcom Randall Veterans Affairs Medical Center, Gainesville, Florida
| | - Qiongyao Hu
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, Florida
- Malcom Randall Veterans Affairs Medical Center, Gainesville, Florida
| | - Victoria R Palzkill
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Tomas A Cort
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Kerri A O'Malley
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, Florida
- Malcom Randall Veterans Affairs Medical Center, Gainesville, Florida
| | - Scott A Berceli
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, Florida
- Malcom Randall Veterans Affairs Medical Center, Gainesville, Florida
| | - Salvatore T Scali
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, Florida
- Malcom Randall Veterans Affairs Medical Center, Gainesville, Florida
| | - Terence E Ryan
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
- Center for Exercise Science, University of Florida, Gainesville, Florida
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Palzkill VR, Thome T, Murillo AL, Khattri RB, Ryan TE. Increasing plasma L-kynurenine impairs mitochondrial oxidative phosphorylation prior to the development of atrophy in murine skeletal muscle: A pilot study. Front Physiol 2022; 13:992413. [PMID: 36246103 PMCID: PMC9562971 DOI: 10.3389/fphys.2022.992413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/22/2022] [Indexed: 11/14/2022] Open
Abstract
Introduction: L-Kynurenine (L-Kyn), a product of tryptophan (Trp) catabolism, has been linked with impairments in walking speed, muscle strength/size, and physical function. The purpose of this pilot study was to develop a dietary model that elevates plasma L-Kyn levels in mice and characterize its impact on muscle health and function. Methods: Four-month-old C57BL6J male mice were randomized to either a L-Kyn supplemented (150 mg/kg) or chow diet for 10 weeks. Plasma L-Kyn and Trp levels were measured via mass spectrometry. Primary outcomes included assessments of muscle weights, myofiber cross-sectional area (CSA), nerve-stimulated contractile performance, and mitochondrial oxidative phosphorylation (OXPHOS) and hydrogen peroxide (H2O2) production. Additional experiments in cultured myotubes explored the impact of enhancing L-Kyn metabolism. Results: Mice randomized to the L-Kyn diet displayed significant increases in plasma L-Kyn levels (p = 0.0028) and the L-Kyn/Trp ratio (p = 0.011) when compared to chow fed mice. Food intake and body weights were not different between groups. There were no detectable differences in muscle weights, myofiber CSA, or contractile performance. L-Kyn fed mice displayed reductions in mitochondrial OXPHOS (p = 0.05) and maximal ADP-stimulated respiration (p = 0.0498). In cultured myotubes, overexpression of peroxisome proliferator-activated receptor-gamma coactivator 1 alpha prevented atrophy and proteolysis, as well as deficits in mitochondrial respiration with L-Kyn treatment. Conclusion: Dietary feeding of L-Kyn increases plasma L-Kyn levels and the L-Kyn/Trp ratio in healthy male mice. Mitochondrial impairments in muscle were observed in mice with elevated L-Kyn without changes in muscle size or function. Enhancing L-Kyn metabolism can protect against these effects in culture myotubes.
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Affiliation(s)
- Victoria R. Palzkill
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
| | - Trace Thome
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
| | - Ania L. Murillo
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
| | - Ram B. Khattri
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
| | - Terence E. Ryan
- Department of Applied Physiology and Kinesiology, Gainesville, FL, United States
- Center for Exercise Science, Gainesville, FL, United States
- Myology Institute, University of Florida, Gainesville, FL, United States
- *Correspondence: Terence E. Ryan,
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Kim K, Anderson EM, Fazzone B, Harland KC, Hu Q, Khattri RB, Salyers Z, Palzkill VR, Cort TA, O'Malley KA, Berceli SA, Scali ST, Ryan TE. Assessment of hindlimb myopathy and mitochondrial bioenergetics in a unique mouse model of access‐related hand dysfunction. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kyoungrae Kim
- Department of Applied Physiology and KinesiologyUniversity of FloridaGainesvilleFL
| | - Erik M. Anderson
- Vascular Surgery and Endovascular TherapyUniversity of FloridaGainesvilleFL
- University of FloridaGainesvilleFL
| | - Brian Fazzone
- Vascular Surgery and Endovascular TherapyUniversity of FloridaGainesvilleFL
- University of FloridaGainesvilleFL
| | - Kenneth C. Harland
- Vascular Surgery and Endovascular TherapyUniversity of FloridaGainesvilleFL
- University of FloridaGainesvilleFL
| | - Qiongyao Hu
- Vascular Surgery and Endovascular TherapyUniversity of FloridaGainesvilleFL
- University of FloridaGainesvilleFL
| | - Ram B. Khattri
- Department of Applied Physiology and KinesiologyUniversity of FloridaGainesvilleFL
| | - Zach Salyers
- Department of Applied Physiology and KinesiologyUniversity of FloridaGainesvilleFL
| | - Victoria R. Palzkill
- Department of Applied Physiology and KinesiologyUniversity of FloridaGainesvilleFL
| | - Tomas A. Cort
- Department of Applied Physiology and KinesiologyUniversity of FloridaGainesvilleFL
| | - Kerri A. O'Malley
- Vascular Surgery and Endovascular TherapyUniversity of FloridaGainesvilleFL
- University of FloridaGainesvilleFL
| | - Scott A. Berceli
- Vascular Surgery and Endovascular TherapyUniversity of FloridaGainesvilleFL
- University of FloridaGainesvilleFL
| | | | - Terence E. Ryan
- Department of Applied Physiology and KinesiologyUniversity of FloridaGainesvilleFL
- Center for Exercise ScienceUniversity of FloridaGainesvilleFL
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Myer C, Abdelrahman L, Banerjee S, Khattri RB, Merritt ME, Junk AK, Lee RK, Bhattacharya SK. Aqueous humor metabolite profile of pseudoexfoliation glaucoma is distinctive. Mol Omics 2021; 16:425-435. [PMID: 32149291 DOI: 10.1039/c9mo00192a] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Pseudoexfoliation (PEX) is a known cause of secondary open angle glaucoma. PEX glaucoma is associated with structural and metabolic changes in the eye. Despite similarities, PEX and primary open angle glaucoma (POAG) may have differences in the composition of metabolites. We analyzed the metabolites of the aqueous humor (AH) of PEX subjects sequentially first using nuclear magnetic resonance (1H NMR: HSQC and TOCSY), and subsequently with liquid chromatography tandem mass spectrometry (LC-MS/MS) implementing isotopic ratio outlier analysis (IROA) quantification. The findings were compared with previous results for POAG and control subjects analyzed using identical sequential steps. We found significant differences in metabolites between the three conditions. Principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) indicated clear grouping based on the metabolomes of the three conditions. We used machine learning algorithms and a percentage set of the data to train, and utilized a different or larger dataset to test whether a trained model can correctly classify the test dataset as PEX, POAG or control. Three different algorithms: linear support vector machines (SVM), deep learning, and a neural network were used for prediction. They all accurately classified the test datasets based on the AH metabolome of the sample. We next compared the AH metabolome with known AH and TM proteomes and genomes in order to understand metabolic pathways that may contribute to alterations in the AH metabolome in PEX. We found potential protein/gene pathways associated with observed significant metabolite changes in PEX.
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Affiliation(s)
- Ciara Myer
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. and Miami Integrative Metabolomics Research Center, University of Miami, Miami, Florida, USA
| | - Leila Abdelrahman
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. and Miami Integrative Metabolomics Research Center, University of Miami, Miami, Florida, USA
| | - Santanu Banerjee
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. and Miami Integrative Metabolomics Research Center, University of Miami, Miami, Florida, USA and Department of Surgery, University of Miami, Miami, Florida, USA
| | | | | | - Anna K Junk
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. and Miami Integrative Metabolomics Research Center, University of Miami, Miami, Florida, USA and Miami Veterans Affairs Healthcare System, Miami, Florida, USA
| | - Richard K Lee
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. and Miami Integrative Metabolomics Research Center, University of Miami, Miami, Florida, USA
| | - Sanjoy K Bhattacharya
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. and Miami Integrative Metabolomics Research Center, University of Miami, Miami, Florida, USA
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Henry JA, Khattri RB, Guingab-Cagmat J, Merritt ME, Garrett TJ, Patterson JT, Lohr KE. Intraspecific variation in polar and nonpolar metabolite profiles of a threatened Caribbean coral. Metabolomics 2021; 17:60. [PMID: 34143280 DOI: 10.1007/s11306-021-01808-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 05/29/2021] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Research aimed at understanding intraspecific variation among corals could substantially increase understanding of coral biology and improve outcomes of active restoration efforts. Metabolomics is useful for identifying physiological drivers leading to variation among genotypes and has the capacity to improve our selection of candidate corals that express phenotypes beneficial to restoration. OBJECTIVES Our study aims to compare metabolomic profiles among known, unique genotypes of the threatened coral Acropora cervicornis. In doing so, we seek information related to the physiological characteristics driving variation among genotypes, which could aid in identifying genets with desirable traits for restoration. METHODS We applied proton nuclear magnetic resonance (1H-NMR) and liquid chromatography-mass spectrometry (LC-MS) to identify and compare metabolomic profiles for seven unique genotypes of A. cervicornis that previously exhibited phenotypic variation in a common garden coral nursery. RESULTS Significant variation in polar and nonpolar metabolite profiles was found among A. cervicornis genotypes. Despite difficulties identifying all significant metabolites driving separation among genotypes, our data support previous findings and further suggest metabolomic profiles differ among various genotypes of the threatened species A. cervicornis. CONCLUSION The implementation of metabolomic analyses allowed identification of several key metabolites driving separation among genotypes and expanded our understanding of the A. cervicornis metabolome. Although our research is specific to A. cervicornis, these findings have broad relevance for coral biology and active restoration. Furthermore, this study provides specific information on the understudied A. cervicornis metabolome and further confirmation that differences in metabolome structure could drive phenotypic variation among genotypes.
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Affiliation(s)
- Joseph A Henry
- Program in Fisheries and Aquatic Sciences, School of Forest, Fisheries, and Geomatics Sciences, University of Florida/IFAS, 7922 NW 71st Street, Gainesville, FL, 32653, USA.
| | - Ram B Khattri
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Joy Guingab-Cagmat
- Southeast Center for Integrated Metabolomics, Clinical and Translational Science Institute, University of Florida, Gainesville, FL, USA
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Timothy J Garrett
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Joshua T Patterson
- Program in Fisheries and Aquatic Sciences, School of Forest, Fisheries, and Geomatics Sciences, University of Florida/IFAS, 7922 NW 71st Street, Gainesville, FL, 32653, USA
- The Florida Aquarium, Center for Conservation, 529 Estuary Shore Ln, Apollo Beach, FL, 33572-2205, USA
| | - Kathryn E Lohr
- Office of National Marine Sanctuaries, National Oceanic and Atmospheric Administration, Silver Spring, MD, USA
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10
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Thome T, Kumar RA, Burke SK, Khattri RB, Salyers ZR, Kelley RC, Coleman MD, Christou DD, Hepple RT, Scali ST, Ferreira LF, Ryan TE. Impaired muscle mitochondrial energetics is associated with uremic metabolite accumulation in chronic kidney disease. JCI Insight 2020; 6:139826. [PMID: 33290279 PMCID: PMC7821598 DOI: 10.1172/jci.insight.139826] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 11/25/2020] [Indexed: 01/01/2023] Open
Abstract
Chronic kidney disease (CKD) causes progressive skeletal myopathy involving atrophy, weakness, and fatigue. Mitochondria have been thought to contribute to skeletal myopathy; however, the molecular mechanisms underlying muscle metabolism changes in CKD are unknown. We employed a comprehensive mitochondrial phenotyping platform to elucidate the mechanisms of skeletal muscle mitochondrial impairment in mice with adenine-induced CKD. CKD mice displayed significant reductions in mitochondrial oxidative phosphorylation (OXPHOS), which was strongly correlated with glomerular filtration rate, suggesting a link between kidney function and muscle mitochondrial health. Biochemical assays uncovered that OXPHOS dysfunction was driven by reduced activity of matrix dehydrogenases. Untargeted metabolomics analyses in skeletal muscle revealed a distinct metabolite profile in CKD muscle including accumulation of uremic toxins that strongly associated with the degree of mitochondrial impairment. Additional muscle phenotyping found CKD mice experienced muscle atrophy and increased muscle protein degradation, but only male CKD mice had lower maximal contractile force. CKD mice had morphological changes indicative of destabilization in the neuromuscular junction. This study provides the first comprehensive evaluation of mitochondrial health in murine CKD muscle to our knowledge and uncovers several unknown uremic metabolites that strongly associate with the degree of mitochondrial impairment.
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Affiliation(s)
- Trace Thome
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance
| | - Ravi A Kumar
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance
| | - Sarah K Burke
- Department of Physical Therapy, College of Public Health and Health Professions
| | - Ram B Khattri
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance
| | - Zachary R Salyers
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance
| | - Rachel C Kelley
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance
| | - Madeline D Coleman
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance
| | - Demetra D Christou
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance.,Center for Exercise Science, College of Health & Human Performance, and
| | - Russell T Hepple
- Department of Physical Therapy, College of Public Health and Health Professions
| | - Salvatore T Scali
- Division of Vascular Surgery and Endovascular Therapy, Department of Surgery, College of Medicine, University of Florida, Gainesville, Florida, USA.,Malcom Randall Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Leonardo F Ferreira
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance.,Center for Exercise Science, College of Health & Human Performance, and
| | - Terence E Ryan
- Department of Applied Physiology and Kinesiology, College of Health & Human Performance.,Center for Exercise Science, College of Health & Human Performance, and
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11
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Myer C, Perez J, Abdelrahman L, Mendez R, Khattri RB, Junk AK, Bhattacharya SK. Differentiation of soluble aqueous humor metabolites in primary open angle glaucoma and controls. Exp Eye Res 2020; 194:108024. [PMID: 32246983 DOI: 10.1016/j.exer.2020.108024] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/22/2020] [Accepted: 03/23/2020] [Indexed: 01/06/2023]
Abstract
We report an analysis of the aqueous humor (AH) metabolome of primary open angle glaucoma (POAG) in comparison to normal controls. The AH samples were obtained from human donors [control (n = 35), POAG (n = 23)]. The AH samples were subjected to one-dimensional 1H nuclear magnetic resonance (NMR) analyses on a Bruker Avance 600 MHz instrument with a 1.7 mM NMR probe. The same samples were then subjected to isotopic ratio outlier analysis (IROA) using a Q Exactive orbitrap mass spectrometer after chromatography on an Accela 600 HPLC. Clusterfinder Build 3.1.10 was used for identification and quantification based on long-term metabolite matrix standards. In total, 278 metabolites were identified in control samples and 273 in POAG AH. The metabolites identified were fed into previously reported proteome and genome information and the OmicsNet interaction network generator to construct a protein-metabolite interactions network with an embedded protein-protein network. Significant differences in metabolite composition in POAG compared to controls were identified indicating potential protein/gene pathways associated with these metabolites. These results will expand our previous understanding of the impeded AH metabolite composition, provide new insight into the regulation of AH outflow, and likely aid in future AH and trabecular meshwork multi-omics network analyses.
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Affiliation(s)
- Ciara Myer
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Miami Integrative Metabolomics Research Center, University of Miami, Miami, FL, USA
| | - Jordan Perez
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Miami Integrative Metabolomics Research Center, University of Miami, Miami, FL, USA; Case Western Reserve University, Cleveland, OH, USA
| | - Leila Abdelrahman
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Miami Integrative Metabolomics Research Center, University of Miami, Miami, FL, USA
| | - Roberto Mendez
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Miami Integrative Metabolomics Research Center, University of Miami, Miami, FL, USA; Department of Surgery, University of Miami, Miami, FL, USA
| | - Ram B Khattri
- Department of Biochemistry and Molecular Biochemistry, University of Florida, Gainesville, FL, USA
| | - Anna K Junk
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Miami Integrative Metabolomics Research Center, University of Miami, Miami, FL, USA; Miami Veterans Affairs Health Care System, Miami, FL, USA
| | - Sanjoy K Bhattacharya
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA; Miami Integrative Metabolomics Research Center, University of Miami, Miami, FL, USA.
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12
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Khattri RB, Morris DL, Bilinovich SM, Manandhar E, Napper KR, Sweet JW, Modarelli DA, Leeper TC. Identifying Ortholog Selective Fragment Molecules for Bacterial Glutaredoxins by NMR and Affinity Enhancement by Modification with an Acrylamide Warhead. Molecules 2019; 25:E147. [PMID: 31905878 PMCID: PMC6983068 DOI: 10.3390/molecules25010147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 12/30/2022] Open
Abstract
Illustrated here is the development of a new class of antibiotic lead molecules targeted at Pseudomonas aeruginosa glutaredoxin (PaGRX). This lead was produced to (a) circumvent efflux-mediated resistance mechanisms via covalent inhibition while (b) taking advantage of species selectivity to target a fundamental metabolic pathway. This work involved four components: a novel workflow for generating protein specific fragment hits via independent nuclear magnetic resonance (NMR) measurements, NMR-based modeling of the target protein structure, NMR guided docking of hits, and synthetic modification of the fragment hit with a vinyl cysteine trap moiety, i.e., acrylamide warhead, to generate the chimeric lead. Reactivity of the top warhead-fragment lead suggests that the ortholog selectivity observed for a fragment hit can translate into a substantial kinetic advantage in the mature warhead lead, which bodes well for future work to identify potent, species specific drug molecules targeted against proteins heretofore deemed undruggable.
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Affiliation(s)
- Ram B. Khattri
- Department of Physiology and Functional genomics, University of Florida, Gainesville, FL 32610, USA;
| | - Daniel L. Morris
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA; (D.L.M.); (K.R.N.); (J.W.S.); (D.A.M.)
| | - Stephanie M. Bilinovich
- Department of Pediatrics and Human Development, Michigan State University, East Lansing, MI 48824, USA;
| | | | - Kahlilah R. Napper
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA; (D.L.M.); (K.R.N.); (J.W.S.); (D.A.M.)
| | - Jacob W. Sweet
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA; (D.L.M.); (K.R.N.); (J.W.S.); (D.A.M.)
| | - David A. Modarelli
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA; (D.L.M.); (K.R.N.); (J.W.S.); (D.A.M.)
| | - Thomas C. Leeper
- Department of Chemistry and Biochemistry, Kennesaw State University, GA 30144, USA
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13
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Chen H, Humes ST, Robinson SE, Loeb JC, Sabaraya IV, Saleh NB, Khattri RB, Merritt ME, Martyniuk CJ, Lednicky JA, Sabo-Attwood T. Single-walled carbon nanotubes repress viral-induced defense pathways through oxidative stress. Nanotoxicology 2019; 13:1176-1196. [PMID: 31328592 DOI: 10.1080/17435390.2019.1645903] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Exposure of lung cells in vitro or mice to single-walled carbon nanotubes (SWCNTs) directly to the respiratory tract leads to a reduced host anti-viral immune response to infection with influenza A virus H1N1 (IAV), resulting in significant increases in viral titers. This suggests that unintended exposure to nanotubes via inhalation may increase susceptibility to notorious respiratory viruses that carry a high social and economic burden globally. However, the molecular mechanisms that contribute to viral susceptibility have not been elucidated. In the present study, we identified the retinoic acid-induced gene I (RIG-I) like receptors (RLRs)/mitochondrial antiviral signaling (MAVS) pathway as a target of SWCNT-induced oxidative stress in small airway epithelial cells (SAEC) that contribute to significantly enhanced influenza viral titers. Exposure of SAEC to SWCNTs increases viral titers while repressing several aspects of the RLR pathway, including mRNA expression of key genes (e.g. IFITs, RIG-I, MDA5, IFNβ1, CCL5). SWCNTs also reduce mitochondrial membrane potential without altering oxygen consumption rates. Our findings also indicate that SWCNTs can impair formation of MAVS prion-like aggregates, which is known to impede downstream activation of the RLR pathway and hence the transcriptional production of interferon-regulated anti-viral genes and cytokines. Furthermore, application of the antioxidant NAC alleviates inhibition of gene expression levels by SWCNTs, as well as MAVS signalosome formation, and increased viral titers. These data provide evidence of targeted impairment of anti-viral signaling networks that are vital to immune defense mechanisms in lung cells, contributing to increased susceptibility to IAV infections by SWCNTs.
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Affiliation(s)
- Hao Chen
- Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida , Gainesville , FL , USA
| | - Sara T Humes
- Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida , Gainesville , FL , USA
| | - Sarah E Robinson
- Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida , Gainesville , FL , USA
| | - Julia C Loeb
- Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida , Gainesville , FL , USA
| | - Indu V Sabaraya
- Department of Department of Civil, Architectural, and Environmental Engineering, University of Texas Austin , Austin , TX , USA
| | - Navid B Saleh
- Department of Department of Civil, Architectural, and Environmental Engineering, University of Texas Austin , Austin , TX , USA
| | - Ram B Khattri
- Department of Biochemistry & Molecular Biology, University of Florida , Gainesville , FL , USA
| | - Matthew E Merritt
- Department of Biochemistry & Molecular Biology, University of Florida , Gainesville , FL , USA
| | - Christopher J Martyniuk
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida , Gainesville , FL , USA
| | - John A Lednicky
- Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida , Gainesville , FL , USA
| | - Tara Sabo-Attwood
- Department of Environmental and Global Health, Center for Environmental and Human Toxicology and Emerging Pathogens Institute, University of Florida , Gainesville , FL , USA
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14
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Osis G, Webster KL, Harris AN, Lee HW, Chen C, Fang L, Romero MF, Khattri RB, Merritt ME, Verlander JW, Weiner ID. Regulation of renal NaDC1 expression and citrate excretion by NBCe1-A. Am J Physiol Renal Physiol 2019; 317:F489-F501. [PMID: 31188034 PMCID: PMC6732450 DOI: 10.1152/ajprenal.00015.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 05/20/2019] [Accepted: 06/07/2019] [Indexed: 11/22/2022] Open
Abstract
Citrate is critical for acid-base homeostasis and to prevent calcium nephrolithiasis. Both metabolic acidosis and hypokalemia decrease citrate excretion and increase expression of Na+-dicarboxylate cotransporter 1 (NaDC1; SLC13A2), the primary protein involved in citrate reabsorption. However, the mechanisms transducing extracellular signals and mediating these responses are incompletely understood. The purpose of the present study was to determine the role of the Na+-coupled electrogenic bicarbonate cotransporter (NBCe1) A variant (NBCe1-A) in citrate metabolism under basal conditions and in response to acid loading and hypokalemia. NBCe1-A deletion increased citrate excretion and decreased NaDC1 expression in the proximal convoluted tubules (PCT) and proximal straight tubules (PST) in the medullary ray (PST-MR) but not in the PST in the outer medulla (PST-OM). Acid loading wild-type (WT) mice decreased citrate excretion. NaDC1 expression increased only in the PCT and PST-MR and not in the PST-MR. In NBCe1-A knockout (KO) mice, the acid loading change in citrate excretion was unaffected, changes in PCT NaDC1 expression were blocked, and there was an adaptive increase in PST-MR. Hypokalemia in WT mice decreased citrate excretion; NaDC1 expression increased only in the PCT and PST-MR. NBCe1-A KO blocked both the citrate and NaDC1 changes. We conclude that 1) adaptive changes in NaDC1 expression in response to metabolic acidosis and hypokalemia occur specifically in the PCT and PST-MR, i.e., in cortical proximal tubule segments; 2) NBCe1-A is necessary for normal basal, metabolic acidosis and hypokalemia-stimulated citrate metabolism and does so by regulating NaDC1 expression in cortical proximal tubule segments; and 3) adaptive increases in PST-OM NaDC1 expression occur in NBCe1-A KO mice in response to acid loading that do not occur in WT mice.
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Affiliation(s)
- Gunars Osis
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Kierstin L Webster
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Autumn N Harris
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida
| | - Hyun-Wook Lee
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Chao Chen
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Lijuan Fang
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Michael F Romero
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Ram B Khattri
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida
| | - Jill W Verlander
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - I David Weiner
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
- Nephrology and Hypertension Section, North Florida/South Georgia Veterans Health System, Gainesville, Florida
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15
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Abstract
Polarization transfer from unpaired electron radicals to nuclear spins at low-temperature is achieved using microwave irradiation by a process broadly termed dynamic nuclear polarization (DNP). The resulting signal enhancement can easily exceed factors of 104 when paired with cryogenic cooling of the sample. Dissolution-DNP couples low temperature polarization methods with a rapid dissolution step, resulting in a highly polarized solution that can be used for metabolically sensitive magnetic resonance imaging (MRI). Hyperpolarized [1-13C]pyruvate is a powerful metabolic imaging agent for investigation of in vitro and in vivo cellular metabolism by means of NMR spectroscopy and MRI. Radicals (trityl OX063 and BDPA) with narrower EPR linewidths typically produce higher nuclear polarizations when carbon-13 is the target nucleus. Increased solid-state polarization is observed when narrow line radicals are doped with lanthanide ions such as Gd3+, Ho3+, Dy3+, and Tb3+. Earlier results have demonstrated an incongruence between DNP experiments with trityl and BDPA, where the optimal concentrations for polarization transfer are disparate despite similar electron spin resonance linewidths. Here, the effects of Ho-DOTA on the solid-state polarization of [1-13C]pyruvic acid were compared for 3.35 T (1.4 K) and 5 T (1.2 K) systems using BDPA as a radical. Multiple concentrations of BDPA were doped with variable concentrations of Ho-DOTA (0, 0.2, 0.5, 1, and 2 mM), and dissolved in 1 : 1 (v/v) of [1-13C] pyruvic acid/sulfolane mixture. Our results reveal that addition of small amounts of Ho-DOTA in the sample preparation increases the solid-state polarization for [1-13C] pyruvic acid, with the optimum Ho-DOTA concentration of 0.2 mM. Without Ho-DOTA doping, the optimum BDPA concentration found for 3.35 T (1.4 K) is 40 mM, and for 5 T (1.2 K) system it is about 60 mM. In both systems, inclusion of Ho-DOTA in the 13C DNP sample leads to a change in the breadth (ΔDNP) of the extrema between the P(+) and P(-) frequencies in microwave spectra. At no combination of BDPA and Ho3+ did polarizations reach those achievable with trityl. Simplified analysis of increased polarization as a function of decreased electron T1e used to explain results in trityl are insufficient to describe DNP with BDPA.
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Affiliation(s)
- Ram B Khattri
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, USA.
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16
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Khattri RB, Morris DL, Davis CM, Bilinovich SM, Caras AJ, Panzner MJ, Debord MA, Leeper TC. An NMR-Guided Screening Method for Selective Fragment Docking and Synthesis of a Warhead Inhibitor. Molecules 2016; 21:molecules21070846. [PMID: 27438815 PMCID: PMC6274284 DOI: 10.3390/molecules21070846] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/20/2016] [Accepted: 06/22/2016] [Indexed: 02/07/2023] Open
Abstract
Selective hits for the glutaredoxin ortholog of Brucella melitensis are determined using STD NMR and verified by trNOE and (15)N-HSQC titration. The most promising hit, RK207, was docked into the target molecule using a scoring function to compare simulated poses to experimental data. After elucidating possible poses, the hit was further optimized into the lead compound by extension with an electrophilic acrylamide warhead. We believe that focusing on selectivity in this early stage of drug discovery will limit cross-reactivity that might occur with the human ortholog as the lead compound is optimized. Kinetics studies revealed that lead compound 5 modified with an ester group results in higher reactivity than an acrylamide control; however, after modification this compound shows little selectivity for bacterial protein versus the human ortholog. In contrast, hydrolysis of compound 5 to the acid form results in a decrease in the activity of the compound. Together these results suggest that more optimization is warranted for this simple chemical scaffold, and opens the door for discovery of drugs targeted against glutaredoxin proteins-a heretofore untapped reservoir for antibiotic agents.
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Affiliation(s)
- Ram B Khattri
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA.
| | - Daniel L Morris
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA.
| | - Caroline M Davis
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA.
| | - Stephanie M Bilinovich
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Andrew J Caras
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA.
| | - Matthew J Panzner
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA.
| | - Michael A Debord
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA.
| | - Thomas C Leeper
- Department of Chemistry and Biochemistry, The University of Akron, Akron, OH 44325, USA.
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