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Justyna, K.

Publications and source records attributed to Justyna, K..

2 recordsLinked to original sources
bioRxiv2024

Improved synthesis and application of an alkyne-functionalized isoprenoid analogue to study the prenylomes of motor neurons, astrocytes and their stem cell progenitors

Protein prenylation is one example of a broad class of post-translational modifications where proteins are covalently linked to various hydrophobic moieties. To globally identify and monitor levels of all prenylated proteins in a cell simultaneously, our laboratory and others have developed chemical proteomic approaches that rely on the metabolic incorporation of isoprenoid analogues bearing bio-orthogonal functionality followed by enrichment and subsequent quantitative proteomic analysis. Here, several improvements in the synthesis of the alkyne-containing isoprenoid analogue C15AlkOPP are reported to improve synthetic efficiency. Next, metabolic labeling with C15AlkOPP was optimized to obtain useful levels of metabolic incorporation of the probe in several types of primary cells. Those conditions were then used to study the prenylomes of motor neurons (ES-MNs), astrocytes (ES-As), and their embryonic stem cell progenitors (ESCs), which allowed for the identification of 54 prenylated proteins from ESCs, 50 from ES-MNs and 84 from ES-As, representing all types of prenylation. Bioinformatic analysis revealed specific enriched pathways, including nervous system development, chemokine signaling, Rho GTPase signaling, and adhesion. Hierarchical clustering showed that most enriched pathways in all three cell types are related to GTPase activity and vesicular transport. In contrast, STRING analysis showed significant interactions in two populations that appear to be cell type dependent. The data provided herein demonstrates that robust incorporation of C15AlkOPP can be obtained in ES-MNs and related primary cells purified via magnetic-activated cell sorting allowing the identification and quantification of numerous prenylated proteins. These results suggest that metabolic labeling with C15AlkOPP should be an effective approach for investigating the role of prenylated proteins in primary cells in both normal cells and disease pathologies, including ALS. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=96 SRC="FIGDIR/small/583211v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@193cfe1org.highwire.dtl.DTLVardef@134edccorg.highwire.dtl.DTLVardef@1e81deforg.highwire.dtl.DTLVardef@56406_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗
bioRxiv2022

Mevalonate metabolites contribute to granulocyte chemotaxis and mortality in murine endotoxemia

Statins appear to dramatically increase sepsis survival but only when treatment is initiated prior to hospitalization. This implies that statins exhibit a delayed-onset pro-survival benefit in septic patients that results in clinical futility of statin-therapy for patients already diagnosed with sepsis. Identification of mechanisms that contribute to increased sepsis-survival following statin-pretreatment may reveal novel therapeutic targets that do not suffer similar delayed onset benefits. Statins are used to treat hypercholesterolemia and function by inhibiting the production of the rate-limiting metabolite mevalonate. This indirectly inhibits the de novo synthesis of not only cholesterol but also isoprenoids that are involved in prenylation, the post-translational lipid modification of proteins. Mirroring clinical observations, chronic but not acute treatment with simvastatin significantly increased survival in a murine endotoxemia model. This was associated with reduced systemic granulocyte chemotaxis that occurred in a cell-intrinsic manner. In vitro modeling showed that simvastatin abolished chemoattractant responses and that this could be reversed by restoring geranylgeranyl pyrophosphate (GGPP) but not farnesyl pyrophosphate (FPP) nor cholesterol. Treatment with prenyltransferase inhibitors showed that chemoattractant responses were dependent on geranylgeranylation. Proteomic analysis of C15AlkOPP-prenylated proteins identified geranylgeranylated proteins involved in chemoattractant responses, including RHOA, RAC1, CDC42, and GNG2. Given the kinetic problems with initiating statin treatment after sepsis onset, prenyltransferases and geranylgeranylated proteins, such as RAC1 and GNG2, are promising interventional candidates for sepsis and critical inflammatory illness.

immunology↗