Biology subjects

Sims-Lucas, S.

Publications and source records attributed to Sims-Lucas, S..

4 recordsLinked to original sources

bioRxiv2023

Dicarboxylic acid supplementation protects from acute kidney injury via stimulation of renal peroxisomal activity

IntroductionLysine succinylation is a post-translational modification associated with the control of several diseases, including acute kidney injury (AKI). It is suggested that hypersuccinylation favors peroxisomal fatty acid oxidation (FAO) instead of mitochondrial. In addition, the medium-chain fatty acids (MCFAs) dodecanedioic acid (DC12) and octanedioic acid (DC8), upon FAO, generate succinyl-CoA, resulting in hypersuccinylation. DC8 is convenient, inexpensive, easily administered, and efficient. We believe this study could be translated in the future to clinical settings, which would highly benefit patients at high risk of AKI. Methods and ResultsTo test the protective roles of MCFAs during AKI, mice were fed with control, 10% DC12, or 10% DC8 diet, then, subjected to either ischemic-AKI, or cisplatin-AKI models. Supplementation was provided until sacrifice. Biochemical, histologic, genetic, and proteomic analysis were performed, the latter involving a lysine-succinylome-based analysis. Both DC8 and DC12 prevented the rise of AKI markers in mice that underwent renal injury. However, DC8 was even more protective against AKI than DC12. Finally, succinylome analysis evidenced that the kidneys of DC8-fed mice showed an extensive succinylation of peroxisomal activity-related proteins, and a decline in mitochondrial FAO, in comparison to control-fed mice. ConclusionDC8 supplementation drives renal protein hypersuccinylation, promoting a shift from mitochondrial to peroxisomal FAO, and protecting against AKI. Significance StatementLysine succinylation of proteins is shown to control several diseases, including acute kidney injury (AKI). Here we show that mice supplemented with the medium-chain fatty acid octanedioic acid successfully presented a high level of succinylation and were protected from both ischemia-reperfusion- and cisplatin-induced AKI. Moreover, our study demonstrates that peroxisomal activity was increased while mitochondrial activity was preserved, suggesting that the metabolism of diet-obtained medium-chain fatty acids by peroxisomes is renoprotective.

pathology↗

bioRxiv2023

Genetically engineering endothelial niche in human kidney organoids enables multilineage maturation, vascularization, and de novo cell types

Vascularization plays a critical role in organ maturation and cell type development. Drug discovery, organ mimicry, and ultimately transplantation in a clinical setting thereby hinges on achieving robust vascularization of in vitro engineered organs. Here, focusing on human kidney organoids, we overcome this hurdle by combining an inducible ETS translocation variant 2 (ETV2) human induced pluripotent stem cell (iPSC) line, which directs endothelial fate, with a non-transgenic iPSC line in suspension organoid culture. The resulting human kidney organoids show extensive vascularization by endothelial cells with an identity most closely related to endogenous kidney endothelia. Vascularized organoids also show increased maturation of nephron structures including more mature podocytes with improved marker expression, foot process interdigitation, an associated fenestrated endothelium, and the presence of renin+ cells. The creation of an engineered vascular niche capable of improving kidney organoid maturation and cell type complexity is a significant step forward in the path to clinical translation. Furthermore, this approach is orthogonal to native tissue differentiation paths, hence readily adaptable to other organoid systems and thus has the potential for a broad impact on basic and translational organoid studies. Translational StatementDeveloping therapies for patients with kidney diseases relies on a morphologically and physiologically representative in vitro model. Human kidney organoids are an attractive model to recapitulate kidney physiology, however, they are limited by the absence of a vascular network and mature cell populations. In this work, we have generated a genetically inducible endothelial niche that, when combined with an established kidney organoid protocol, induces the maturation of a robust endothelial cell network, induces a more mature podocyte population, and induces the emergence a functional renin population. This advance significantly increases the clinical relevance of human kidney organoids for etiological studies of kidney disease and future regenerative medicine strategies. Graphical AbstractGenetically engineered endothelial niche induces mature cell populations in human kidney organoids O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/542848v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@1b129d4org.highwire.dtl.DTLVardef@313ae3org.highwire.dtl.DTLVardef@111c91org.highwire.dtl.DTLVardef@16a8d45_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2023

Substantial Downregulation of Mitochondrial and Peroxisomal Proteins during Acute Kidney Injury revealed by Data-Independent Acquisition Proteomics

Acute kidney injury (AKI) manifests as a major health concern, particularly for the elderly. Understanding AKI-related proteome changes is critical for prevention and development of novel therapeutics to recover kidney function and to mitigate the susceptibility for recurrent AKI or development of chronic kidney disease. In this study, mouse kidneys were subjected to ischemia-reperfusion injury, and the contralateral kidneys remained uninjured to enable comparison and assess injury-induced changes in the kidney proteome. A fast-acquisition rate ZenoTOF 7600 mass spectrometer was introduced for data-independent acquisition (DIA) for comprehensive protein identification and quantification. Short microflow gradients and the generation of a deep kidney-specific spectral library allowed for high-throughput, comprehensive protein quantification. Upon AKI, the kidney proteome was completely remodeled, and over half of the 3,945 quantified protein groups changed significantly. Downregulated proteins in the injured kidney were involved in energy production, including numerous peroxisomal matrix proteins that function in fatty acid oxidation, such as ACOX1, CAT, EHHADH, ACOT4, ACOT8, and Scp2. Injured mice exhibited severely declined health. The comprehensive and sensitive kidney-specific DIA assays highlighted here feature high-throughput analytical capabilities to achieve deep coverage of the kidney proteome and will serve as useful tools for developing novel therapeutics to remediate kidney function.

molecular biology↗

bioRxiv2021

Metformin Confers Cardiac and Renal Protection in Sudden Cardiac Arrest via AMPK Activation

Cardiac arrest (CA) causes high mortality due to multi-system organ damage attributable to ischemia-reperfusion injury. Recent work in our group found that among diabetic patients who experienced cardiac arrest, those taking metformin had less evidence of cardiac and renal damage after cardiac arrest when compared to those not taking metformin. To investigate the potential for metformin to impact cardiac arrest outcomes, the current study investigates metformin interventions on cardiac and renal outcomes in a non-diabetic CA mouse model. We found that two weeks of metformin pretreatment protects against reduced ejection fraction and reduces kidney ischemia-reperfusion injury at 24 hours post-arrest. This cardiac and renal protection depends on AMPK signaling, as demonstrated by outcomes in mice pretreated with the AMPK activator AICAR or metformin plus the AMPK inhibitor compound C. At this 24-hour time point, gene expression analysis showed that metformin pretreatment caused changes supporting autophagy, antioxidant response, and protein translation. Further investigation found associated improvements in mitochondrial structure and markers of autophagy. We also found that markers of protein nitrosylation between sham and arrest were not significantly different and thus unlikely to be a driver of gene expression differences. Notably, Western analysis indicated that protein synthesis was preserved in arrest hearts of animals pretreated with metformin. The AMPK activation-mediated protection of protein synthesis was also demonstrated in a hypoxia/reoxygenation cell culture model. Despite the positive impacts of pretreatment in vivo and in vitro, metformin did not preserve ejection fraction when deployed at resuscitation. Taken together, we propose that metformins in vivo cardiac preservation occurs through AMPK activation, requires adaptation before arrest, and is associated with preserved protein translation. New and NoteworthyWe leveraged a mouse model of cardiac arrest to study whether metformin pretreatment could protect cardiac function after arrest. We find that AMPK activity is crucial to this protection and characterize several pathways associated with this response. Signaling nodes with strong association may be precise targets to promote cardiac function in ischemia/reperfusion injury or in cardiac stunning.

physiology↗