Direct tests of cytochrome c and c1 functions in the electron transport chain of malaria parasites.
Congratulations to graduate student Tanya Espino-Sanchez and the lab of Dr. Paul Sigala in the Department of Biochemistry at the University of Utah School of Medicine for their recent publication in PNAS!! “Direct tests of cytochrome c and c1 functions in the electron transport chain of malaria parasites”. Proc Natl Acad Sci U S A 2023 May 9;120(19):e2301047120. doi: 10.1073/pnas.2301047120. Epub 2023 May 1.PMID: 37126705 PMCID: PMC10175771
Differences in Antioxidant and Lipid Handling Protein Expression Influence How Cells Expressing Distinct Mutant TP53 Subtypes Maintain Iron Homeostasis
Congratulations to student Cameron Cardona and the lab of Dr. McKale Montgomery in
the Department of Nutritional Sciences at Oklahoma State University in Stillwater for
their recent publication in Cells!! “Differences in Antioxidant and Lipid Handling Protein Expression Influence How Cells Expressing Distinct Mutant TP53 Subtypes Maintain Iron Homeostasis”. Cells. 2022 Jul; 11(13): 2064. PMC9265551
The tumor suppressor TP53 is the most commonly mutated gene in human cancers, and iron is necessary for cancer cell growth and proliferation, but there is a significant gap in knowledge for how the two cooperate to affect cellular physiology. Elucidating this role is complicated, however, because each TP53 mutation subtype exhibits unique phenotypic responses to changes in iron availability. The goal of this work was to determine how cells expressing distinct TP53 mutation subtypes respond to iron restriction. Utilizing a reverse genetics approach, we generated eight isogenic cell lines that either lacked TP53 expression, expressed wild-type TP53, or expressed one of the six most common TP53 “hotspot” mutations. We then employed isobaric peptide labeling and mass spectrometry to quantitively measure changes in global protein expression, both in response to induction of mutant TP53 expression, and in response to iron chelation. Our findings indicate that mutant TP53-dependent sensitivities to iron restriction are not driven by differences in responsiveness to iron chelation, but more so by mutant TP53-dependent differences in cellular antioxidant and lipid handling protein expression. These findings reinforce the importance of distinguishing between TP53 mutation subtypes when investigating approaches to target mutant TP53. We also identify unique TP53-dependent perturbances in protein expression patterns that could be exploited to improve iron-targeted chemotherapeutic strategies.
The total iron quantification was performed at the University of Utah CIHD Iron and Heme Core (DK110858).
Loss of the mitochondrial protein Abcb10 results in altered arginine metabolism in MEL and K562 cells and nutrient stress signaling through ATF4.
Congratulations to past Medical Laboratory Science master’s student Marisa Miljkovic and
Diane Ward, James Cox and John Phillips, members of the Utah U54 Center for Iron and Heme Disorders, for their recent JBC publication entitled “Loss of the mitochondrial protein Abcb10 results in altered arginine metabolism in MEL and K562 cells and nutrient stress signaling through ATF4“. J Biol Chem 2023 Jun 1;104877. PMDI: 37269954
Abcb10 is a mitochondrial membrane protein involved in hemoglobinization of red cells. Abcb10 topology and ATPase domain localization suggest it exports a substrate, likely biliverdin, out of mitochondria that is necessary for hemoglobinization. In this study we generated Abcb10 deletion cell lines in both mouse murine erythroleukemia (MEL) and human erythroid precursor human myelogenous leukemia (K562) cells to better understand the consequences of Abcb10 loss. Loss of Abcb10 resulted in an inability to hemoglobinize upon differentiation in both K562 and MEL cells with reduced heme and intermediate porphyrins and decreased levels of aminolevulinic acid synthase 2 activity. Metabolomic and transcriptional analyses revealed that Abcb10 loss gave rise to decreased cellular arginine levels, increased transcripts for cationic and neutral amino acid transporters with reduced levels of the citrulline to arginine converting enzymes argininosuccinate synthetase and argininosuccinate lyase. The reduced arginine levels in Abcb10 null cells gave rise to decreased proliferative capacity. Arginine supplementation improved both Abcb10 null proliferation and hemoglobinization upon differentiation. Abcb10 null cells showed increased phosphorylation of Eukaryotic Translation Initiation Factor 2 Subunit Alpha (eIF2A), increased expression of nutrient sensing transcription factor ATF4 and downstream targets DNA damage inducible transcript 3 (Chop), ChaC glutathione specific gamma-glutamylcyclotransferase 1 (Chac1) and arginyl-tRNA synthetase 1 (Rars). These results suggest that when the Abcb10 substrate is trapped in the mitochondria, the nutrient sensing machinery is turned on remodeling transcription to block protein synthesis necessary for proliferation and hemoglobin biosynthesis in erythroid models.
This work was supported by a University of Utah CIHD P&F award DK110858 to DMW and the Mutation Generation Detection, Metabolomics and Iron and Heme Cores U54DK110858 at the University of Utah School of Medicine.
Macrophage metabolic rewiring improves heme-suppressed efferocytosis and tissue damage in sickle cell disease.
Richa Sharma, Ada Antypiuk, S. Zebulon Vance, Deepa Manwani, Quentinn Pearce, James Eric Cox, Xiuli An, Karina Yazdanbakhsh, Francesca Vinchi.
Blood 2023 Mar 23;blood.2022018026. doi: 10.1182/blood.2022018026. Online ahead of print. PMID: 36952641
Sickle cell disease (SCD) is hallmarked by an underlying chronic inflammatory condition, which is contributed by heme-activated pro-inflammatory macrophages. While previous studies addressed heme ability to stimulate macrophage inflammatory skewing through TLR4/ROS signaling, how heme alters cell functional properties remains unexplored. Macrophage-mediated immune cell recruitment and apoptotic cell (AC) clearance are relevant in the context of SCD, where tissue damage, cell apoptosis and inflammation occur due to vasoocclusive episodes, hypoxia and ischemic injury. Here we show that heme strongly alters macrophage functional response to AC damage by exacerbating immune cell recruitment and impairing cell efferocytic capacity. In SCD, heme-driven excessive leukocyte influx and defective efferocytosis contribute to exacerbated tissue damage and sustained inflammation. Mechanistically, these events depend on heme-mediated activation of TLR4 signaling and suppression of the transcription factor PPARg and its coactivator PGC1a. These changes reduce efferocytic receptor expression and promote mitochondrial remodeling, resulting in a coordinated functional and metabolic reprogramming of macrophages. Overall, this results in limited AC engulfment, impaired metabolic shift to mitochondrial fatty acid b-oxidation and ultimately reduced secretion of the anti-inflammatory cytokines IL-4 and IL-10, with consequent inhibition of continual efferocytosis, resolution of inflammation and tissue repair. We further demonstrate that impaired phagocytic capacity is recapitulated by macrophage exposure to sickle patients’plasma and improved by hemopexin-mediated heme scavenging, PPARg agonists or IL-4 exposure through functional and metabolic macrophage rewiring. Our data indicate that therapeutic improvement of heme-altered macrophage functional properties via heme scavenging or PGC1a/PPARg modulation significantly ameliorate tissue damage associated with SCD pathophysiology.
This work was supported by University of Utah Center of Excellence in Hematology (CIHD) U54 DK110858 Pilot and Feasibility Grant to F.V. and the Metabolomics Core at the University of Utah School of Medicine.
Protein-metabolite interactomics of carbohydrate metabolism reveal regulation of lactate dehydrogenase.
Congratulations to Kevin Hicks, James Cox and Jared Rutter, members of the Utah U54 Center for Iron and Heme Disorders ,for their recent Science publication entitled “Protein-metabolite interactomics of carbohydrate metabolism reveal regulation of lactate dehydrogenase.” Science 9 Mar 2023 Vol 379, Issue 6636 pp. 996-1003.
Dr. Hicks runs the CCEH-sponsored MIDAS Core at the University of Utah School of Medicine. Check out this cutting edge core!
Metabolic networks are interconnected and influence diverse cellular processes. The protein-metabolite interactions that mediate these networks are frequently low affinity and challenging to systematically discover. We developed mass spectrometry integrated with equilibrium dialysis for the discovery of allostery systematically (MIDAS) to identify such interactions. Analysis of 33 enzymes from human carbohydrate metabolism identified 830 protein-metabolite interactions, including known regulators, substrates, and products as well as previously unreported interactions. We functionally validated a subset of interactions, including the isoform-specific inhibition of lactate dehydrogenase by long-chain acyl–coenzyme A. Cell treatment with fatty acids caused a loss of pyruvate-lactate interconversion dependent on lactate dehydrogenase isoform expression. These protein-metabolite interactions may contribute to the dynamic, tissue-specific metabolic flexibility that enables growth and survival in an ever-changing nutrient environment.
Mitochondrial contact site and cristae organizing system (MICOS) machinery supports heme biosynthesis by enabling optimal performance of ferrochelatase
Congratulations to University of Nebraska Biochemistry Department graduate student Jonathan Dietz, from Oleh Khalimonchuk’s lab, on his paper in Redox Biol on “Mitochondrial contact site and cristae organizing system (MICOS) machinery supports heme biosynthesis by enabling optimal performance of ferrochelatase”. This study was supported by a P&F award U54DK110858.
Lysosomal iron recycling in mouse macrophages is dependent upon both LcytB and Steap3 reductases
Congratulations to University of Utah Medical Laboratory Science graduate student Fanjing Meng, from Diane Ward’s lab, on her paper in Blood Advances on “Lysosomal iron recycling in mouse macrophages is dependent upon both LcytB and Steap3 reductases”. This study was supported by a P&F awarded to DMW U54DK110858.
Critical role for isoprenoids in apicoplast biogenesis by malaria parasites
Congratulations to University of Utah Biochemistry Department graduate student Megan Okada, from Paul Sigala’s lab, on her paper in Elife on “Critical role for isoprenoids in apicoplast biogenesis by malaria parasites”. This study was supported by work from the Metabolomics Core U54DK110858.
MRP5 and MRP9 play a concerted role in male reproduction and mitochondrial function
Congratulations to University of Maryland, College Park Department of Animal and Avian Sciences and Department of Cell Biology and Molecular Genetics graduate student Ian Chambers, from Iqbal Hamza’s lab, on his paper in PNAS on “MRP5 and MRP9 play a concerted role in male reproduction and mitochondrial function”. This study was supported by work from the Metabolomics Core U54DK110858.
Erythroid overproduction of erythroferrone causes iron overload and developmental abnormalities in mice
Congratulations to postdoctoral fellow Richard Coffey in the Ganz and Nemeth lab from the UCLA Center for Iron Disorders for his recent work on erythroid ERFE production and iron overload. Drs. Ganz and Nemeth are members of the Utah CCEH.
The biochemical basis of mitochondrial dysfunction in Zellweger Spectrum Disorder
Congratulations to postdoctoral fellow Esther Nuebel from Jared Rutter’s lab in the Department of Biochemistry at the University of Utah School of Medicine for her recent work on Zellweger Spectrum Disorders and mitochondrial dysfunction. Dr. Rutter is a member of the Utah CIHD and the Metabolomics/Lipidomics core, which is funded by the U54 CIHD, was utilized in this study.
Divergent acyl carrier protein decouples mitochondrial Fe-S cluster biogenesis from fatty acid synthesis in malaria parasites
Congratulations to University of Utah Biochemistry Department graduate student Seyi Falekun, from Paul Sigala’s lab, on his paper in Elife on “Divergent acyl carrier protein decouples mitochondrial Fe-S cluster biogenesis from fatty acid synthesis in malaria parasites. This work was initially funded by a CIHD pilot award.
The ubiquitous mitochondrial protein unfoldase CLPX regulates erythroid heme synthesis by control of iron utilization and heme synthesis enzyme activation and turnover
The ubiquitous mitochondrial protein unfoldase CLPX regulates erythroid heme synthesis by control of iron utilization and heme synthesis enzyme activation and turnover. Rondelli CM, Perfetto M, Danoff A, Bergonia H, Gillis S, O’Neill L, Jackson L, Nicolas G, Puy H, West R, Phillips JD, Yien YY. J Biol Chem. 2021 Jul 16:100972. doi: 10.1016/j.jbc.2021.100972. Online ahead of print. PMID: 34280433
Iron deficiency exacerbates cisplatin- or rhabdomyolysis-induced acute kidney injury through promoting iron-catalyzed oxidative damage
Iron deficiency exacerbates cisplatin- or rhabdomyolysis-induced acute kidney injury through promoting iron-catalyzed oxidative damage. Zhao S, Wang X, Zheng X, Liang X, Wang Z, Zhang J, Zhao X, Zhuang S, Pan Q, Sun F, Shang W, Barasch J, Qiu A. Free Radic Biol Med. 2021 Jul 21;173:81-96. doi: 10.1016/j.freeradbiomed.2021.07.025. Online ahead of print. PMID: 34298093
Iron-dependent apoptosis causes embryotoxicity in inflamed and obese pregnancy
Iron-dependent apoptosis causes embryotoxicity in inflamed and obese pregnancy. Fisher AL, Sangkhae V, Balušíková K, Palaskas NJ, Ganz T, Nemeth E. Nat Commun. 2021 Jun 29;12(1):4026. doi: 10.1038/s41467-021-24333-z. PMID: 34188052