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Albalawy WN, Youm EB, Shipman KE, Trull KJ, Baty CJ, Long KR, Rbaibi Y, Wang XP, Fagunloye OG, White KA, Jurczak MJ, Kashlan OB, Weisz OA. SGLT2-independent effects of canagliflozin on NHE3 and mitochondrial complex I activity inhibit proximal tubule fluid transport and albumin uptake. Am J Physiol Renal Physiol 2024. [PMID: 38660713 DOI: 10.1152/ajprenal.00005.2024] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 04/18/2024] [Indexed: 04/26/2024] Open
Abstract
Beyond glycemic control, SGLT2 inhibitors (SGLT2i) have protective effects on cardiorenal function. Renoprotection has been suggested to involve inhibition of NHE3 leading to reduced ATP-dependent tubular workload and mitochondrial oxygen consumption. NHE3 activity is also important for regulation of endosomal pH, but the effects of SGLT2i on endocytosis are unknown. We used a highly differentiated cell culture model of proximal tubule (PT) cells to determine the direct effects of SGLT2i on Na+-dependent fluid transport and endocytic uptake in this nephron segment. Strikingly, canagliflozin but not empagliflozin reduced fluid transport across cell monolayers, and dramatically inhibited endocytic uptake of albumin. These effects were independent of glucose and occurred at clinically relevant concentrations of drug. Canagliflozin acutely inhibited surface NHE3 activity, consistent with a direct effect, but did not affect endosomal pH or NHE3 phosphorylation. Additionally, canagliflozin rapidly and selectively inhibited mitochondrial complex I activity. Inhibition of mitochondrial complex I by metformin recapitulated the effects of canagliflozin on endocytosis and fluid transport, whereas modulation of downstream effectors AMPK and mTOR did not. Mice given a single dose of canagliflozin excreted twice as much urine over 24 h compared with empagliflozin-treated mice despite similar water intake. We conclude that canagliflozin selectively suppresses Na+-dependent fluid transport and albumin uptake in PT cells via direct inhibition of NHE3 and of mitochondrial function upstream of the AMPK/mTOR axis. These additional targets of canagliflozin contribute significantly to reduced PT Na+-dependent fluid transport in vivo.
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Affiliation(s)
- Wafaa N Albalawy
- Medicine/ Renal Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Elynna B Youm
- Medicine/ Renal Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Katherine E Shipman
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Keelan J Trull
- Department of Chemistry and Biochemistry, University of Notre Dame, Bend, IL, United States
| | - Catherine J Baty
- Department of Medicine, University of Pittsburgh, PITTSBURGH, PA, United States
| | - Kimberly R Long
- Medicine - Renal/Electrolyte, University of Pittsburgh, Pittsburgh, PA, United States
| | - Youssef Rbaibi
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xue-Ping Wang
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Olayemi G Fagunloye
- Medicine/Endocrinology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Katharine A White
- Department of Chemistry and Biochemistry, University of Notre Dame, South Bend, IN, United States
| | - Michael J Jurczak
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Ossama B Kashlan
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ora A Weisz
- Medicine/ Renal Electrolyte Division, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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Undamatla R, Fagunloye OG, Chen J, Edmunds LR, Murali A, Mills A, Xie B, Pangburn MM, Sipula I, Gibson G, St Croix C, Jurczak MJ. Reduced mitophagy is an early feature of NAFLD and liver-specific PARKIN knockout hastens the onset of steatosis, inflammation and fibrosis. Sci Rep 2023; 13:7575. [PMID: 37165006 PMCID: PMC10172344 DOI: 10.1038/s41598-023-34710-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [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: 01/12/2023] [Accepted: 05/05/2023] [Indexed: 05/12/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of pathologies that includes steatosis, steatohepatitis (NASH) and fibrosis and is strongly associated with insulin resistance and type 2 diabetes. Changes in mitochondrial function are implicated in the pathogenesis of NAFLD, particularly in the transition from steatosis to NASH. Mitophagy is a mitochondrial quality control mechanism that allows for the selective removal of damaged mitochondria from the cell via the autophagy pathway. While past work demonstrated a negative association between liver fat content and rates of mitophagy, when changes in mitophagy occur during the pathogenesis of NAFLD and whether such changes contribute to the primary endpoints associated with the disease are currently poorly defined. We therefore undertook the studies described here to establish when alterations in mitophagy occur during the pathogenesis of NAFLD, as well as to determine the effects of genetic inhibition of mitophagy via conditional deletion of a key mitophagy regulator, PARKIN, on the development of steatosis, insulin resistance, inflammation and fibrosis. We find that loss of mitophagy occurs early in the pathogenesis of NAFLD and that loss of PARKIN accelerates the onset of key NAFLD disease features. These observations suggest that loss of mitochondrial quality control in response to nutritional stress may contribute to mitochondrial dysfunction and the pathogenesis of NAFLD.
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Affiliation(s)
- R Undamatla
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA
| | - O G Fagunloye
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA
| | - J Chen
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA
| | - L R Edmunds
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA
| | - A Murali
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA
| | - A Mills
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA
| | - B Xie
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA
| | - M M Pangburn
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA
| | - I Sipula
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA
| | - G Gibson
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, USA
| | - C St Croix
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, USA
| | - M J Jurczak
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, 200 Lothrop Street, BST W1060, Pittsburgh, PA, 15213, USA.
- Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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Undamatla R, Fagunloye OG, Chen J, Edmunds LR, Murali A, Mills A, Xie B, Pangburn MM, Sipula I, Gibson G, Croix CS, Jurczak MJ. Reduced hepatocyte mitophagy is an early feature of NAFLD pathogenesis and hastens the onset of steatosis, inflammation and fibrosis. Res Sq 2023:rs.3.rs-2469234. [PMID: 36711642 PMCID: PMC9882688 DOI: 10.21203/rs.3.rs-2469234/v1] [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] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of pathologies that includes steatosis, steatohepatitis (NASH) and fibrosis and is strongly associated with insulin resistance and type 2 diabetes. Changes in mitochondrial function are implicated in the pathogenesis of NAFLD, particularly in the transition from steatosis to NASH. Mitophagy is a mitochondrial quality control mechanism that allows for the selective removal of damaged mitochondria from the cell via the autophagy pathway. While past work demonstrated a negative association between liver fat content and rates of mitophagy, when changes in mitophagy occur during the pathogenesis of NAFLD and whether such changes contribute to the primary endpoints associated with the disease are currently poorly defined. We therefore undertook the studies described here to establish when alterations in mitophagy occur during the pathogenesis of NAFLD, as well as to determine the effects of genetic inhibition of mitophagy via conditional deletion of a key mitophagy regulator, PARKIN, on the development of steatosis, insulin resistance, inflammation and fibrosis. We find that loss of mitophagy occurs early in the pathogenesis of NAFLD and that loss of PARKIN hastens the onset but not severity of key NAFLD disease features. These observations suggest that loss of mitochondrial quality control in response to nutritional stress may contribute to mitochondrial dysfunction and the pathogenesis of NAFLD.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Ian Sipula
- University of Pittsburgh School of Medicine
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Smith M, Yadav S, Fagunloye OG, Pels NA, Horton DA, Alsultan N, Borns A, Cousin C, Dixon F, Mann VH, Lee C, Brindley PJ, El-Sayed NM, Bridger JM, Knight M. PIWI silencing mechanism involving the retrotransposon nimbus orchestrates resistance to infection with Schistosoma mansoni in the snail vector, Biomphalaria glabrata. PLoS Negl Trop Dis 2021; 15:e0009094. [PMID: 34495959 PMCID: PMC8462715 DOI: 10.1371/journal.pntd.0009094] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 09/24/2021] [Accepted: 07/27/2021] [Indexed: 12/23/2022] Open
Abstract
Background Schistosomiasis remains widespread in many regions despite efforts at its elimination. By examining changes in the transcriptome at the host-pathogen interface in the snail Biomphalaria glabrata and the blood fluke Schistosoma mansoni, we previously demonstrated that an early stress response in juvenile snails, manifested by induction of heat shock protein 70 (Hsp 70) and Hsp 90 and of the reverse transcriptase (RT) domain of the B. glabrata non-LTR- retrotransposon, nimbus, were critical for B. glabrata susceptibility to S. mansoni. Subsequently, juvenile B. glabrata BS-90 snails, resistant to S. mansoni at 25°C become susceptible by the F2 generation when maintained at 32°C, indicating an epigenetic response. Methodology/Principal findings To better understand this plasticity in susceptibility of the BS-90 snail, mRNA sequences were examined from S. mansoni exposed juvenile BS-90 snails cultured either at 25°C (non-permissive temperature) or 32°C (permissive). Comparative analysis of transcriptomes from snails cultured at the non-permissive and permissive temperatures revealed that whereas stress related transcripts dominated the transcriptome of susceptible BS-90 juvenile snails at 32°C, transcripts encoding proteins with a role in epigenetics, such as PIWI (BgPiwi), chromobox protein homolog 1 (BgCBx1), histone acetyltransferase (BgHAT), histone deacetylase (BgHDAC) and metallotransferase (BgMT) were highly expressed in those cultured at 25°C. To identify robust candidate transcripts that will underscore the anti-schistosome phenotype in B. glabrata, further validation of the differential expression of the above transcripts was performed by using the resistant BS-90 (25°C) and the BBO2 susceptible snail stock whose genome has now been sequenced and represents an invaluable resource for molecular studies in B. glabrata. A role for BgPiwi in B. glabrata susceptibility to S. mansoni, was further examined by using siRNA corresponding to the BgPiwi encoding transcript to suppress expression of BgPiwi, rendering the resistant BS-90 juvenile snail susceptible to infection at 25°C. Given transposon silencing activity of PIWI as a facet of its role as guardian of the integrity of the genome, we examined the expression of the nimbus RT encoding transcript at 120 min after infection of resistant BS90 piwi-siRNA treated snails. We observed that nimbus RT was upregulated, indicating that modulation of the transcription of the nimbus RT was associated with susceptibility to S. mansoni in BgPiwi-siRNA treated BS-90 snails. Furthermore, treatment of susceptible BBO2 snails with the RT inhibitor lamivudine, before exposure to S. mansoni, blocked S. mansoni infection concurrent with downregulation of the nimbus RT transcript and upregulation of the BgPiwi encoding transcript in the lamivudine-treated, schistosome-exposed susceptible snails. Conclusions and significance These findings support a role for the interplay of BgPiwi and nimbus in the epigenetic modulation of plasticity of resistance/susceptibility in the snail-schistosome relationship. Progress is being made to eliminate schistosomiasis, a tropical disease that remains endemic in the tropics and neotropics. In 2020, WHO proposed controlling the snail population as part of a strategy toward reducing schistosomiasis, a vector borne disease, by 2025. The life cycle of the causative parasite is, however, complex and in the absence of vaccines, new drugs, and access to clean water and sanitation, reduction of schistosomiasis will remain elusive. To break the parasite’s life cycle during the snail stage of its development, a better understanding of the molecular basis of how schistosomes survive, or not, in the snail is required. By examining changes in the transcriptome at the host-pathogen interface in the snail Biomphalaria glabrata and Schistosoma mansoni, we showed that early stress response, manifested by the induction of Heat Shock Proteins (Hsps) and the RT domain of the non-LTR retrotransposon, nimbus, were critical for snail susceptibility. Subsequently, juvenile B. glabrata BS-90 snails, resistant to S. mansoni at 25°C were observed to become susceptible by the F2 generation when maintained at 32°C, indicating an epigenetic response. This study confirms these earlier results and shows an interplay between PIWI and nimbus in the anti-schistosome response in the snail host.
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Affiliation(s)
- Michael Smith
- Howard University, Washington, District of Columbia, United States of America
| | - Swara Yadav
- Division of Science & Mathematics, University of the District of Columbia, Washington, District of Columbia, United States of America
| | - Olayemi G. Fagunloye
- Division of Science & Mathematics, University of the District of Columbia, Washington, District of Columbia, United States of America
| | - Nana Adjoa Pels
- Division of Science & Mathematics, University of the District of Columbia, Washington, District of Columbia, United States of America
| | - Daniel A. Horton
- Centre for Genome Engineering and Maintenance, Division of Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University, London, United Kingdom
| | - Nashwah Alsultan
- Division of Science & Mathematics, University of the District of Columbia, Washington, District of Columbia, United States of America
| | - Andrea Borns
- Division of Science & Mathematics, University of the District of Columbia, Washington, District of Columbia, United States of America
| | - Carolyn Cousin
- Division of Science & Mathematics, University of the District of Columbia, Washington, District of Columbia, United States of America
| | - Freddie Dixon
- Division of Science & Mathematics, University of the District of Columbia, Washington, District of Columbia, United States of America
| | - Victoria H. Mann
- Department of Microbiology, Immunology & Tropical Medicine, Research Center for Neglected Diseases of Poverty, School of Medicine & Health Sciences, The George Washington University, Washington, District of Columbia, United States of America
| | - Clarence Lee
- Division of Science & Mathematics, University of the District of Columbia, Washington, District of Columbia, United States of America
| | - Paul J. Brindley
- Department of Microbiology, Immunology & Tropical Medicine, Research Center for Neglected Diseases of Poverty, School of Medicine & Health Sciences, The George Washington University, Washington, District of Columbia, United States of America
| | - Najib M. El-Sayed
- Department of Cell Biology and Molecular Genetics and Center for Bioinformatics and Computational Biology, University of Maryland, College Park, Maryland, United States of America
| | - Joanna M. Bridger
- Centre for Genome Engineering and Maintenance, Division of Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University, London, United Kingdom
| | - Matty Knight
- Howard University, Washington, District of Columbia, United States of America
- Department of Microbiology, Immunology & Tropical Medicine, Research Center for Neglected Diseases of Poverty, School of Medicine & Health Sciences, The George Washington University, Washington, District of Columbia, United States of America
- * E-mail: ,
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