- Browse by Author
Browsing by Author "Clemmer, David E."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Analysis of Keratinocytic Exosomes from Diabetic and Nondiabetic Mice by Charge Detection Mass Spectrometry(American Chemical Society, 2022) Brown, Brooke A.; Guda, Poornachander R.; Zeng, Xuyao; Anthony, Adam; Couse, Andrew; Barnes, Lauren F.; Sharon, Edie M.; Trinidad, Jonathan C.; Sen, Chandan K.; Jarrold, Martin F.; Ghatak, Subhadip; Clemmer, David E.; Surgery, School of MedicineUnresolved inflammation compromises diabetic wound healing. Recently, we reported that inadequate RNA packaging in murine wound-edge keratinocyte-originated exosomes (Exoκ) leads to persistent inflammation [Zhou, X. ACS Nano 2020, 14(10), 12732-12748]. Herein, we use charge detection mass spectrometry (CDMS) to analyze intact Exoκ isolated from a 5 day old wound-edge tissue of diabetic mice and a heterozygous nondiabetic littermate control group. In CDMS, the charge (z) and mass-to-charge ratio (m/z) of individual exosome particles are measured simultaneously, enabling the direct analysis of masses in the 1-200 MDa range anticipated for exosomes. These measurements reveal a broad mass range for Exoκ from ∼10 to >100 MDa. The m and z values for these exosomes appear to fall into families (subpopulations); a statistical modeling analysis partially resolves ∼10-20 Exoκ subpopulations. Complementary proteomics, immunofluorescence, and electron microscopy studies support the CDMS results that Exoκ from diabetic and nondiabetic mice vary substantially. Subpopulations having high z (>650) and high m (>44 MDa) are more abundant in nondiabetic animals. We propose that these high m and z particles may arise from differences in cargo packaging. The veracity of this idea is discussed in light of other recent CDMS results involving genome packaging in vaccines, as well as exosome imaging experiments. Characterization of intact exosome particles based on the physical properties of m and z provides a new means of investigating wound healing and suggests that CDMS may be useful for other pathologies.Item COMPARATIVE ANALYSIS OF THE DISCORDANCE BETWEEN THE GLOBAL TRANSCRIPTIONAL AND PROTEOMIC RESPONSE OF THE YEAST SACCHAROMYCES CEREVISIAE TO DELETION OF THE F-BOX PROTEIN, GRR1(2010-05) Heyen, Joshua William; Goebl, Mark, 1958-; Roach, Peter J.; Clemmer, David E.; Wang, Mu; Chen, JakeThe Grr1 (Glucose Repression Resistant) protein in Saccharomyces cerevisiae is an F-box protein for the E3 ubiquitin ligase protein complex known as the SCFGrr1 (Skp, Cullin, F-box). F-box proteins serve as substrate receptors for this complex and in this capacity Grr1 serves to promote the ubiquitylation and subsequent proteasomal degradation of a number of intracellular protein substrates. Substrates of SCFGrr1 include the G1-S phase cyclins, Cln1 and Cln2, the Cdc42 effectors and cell polarity proteins, Gic1 and Gic2, the FCH-bar domain protein, Hof1, required for cytokinesis, the meiosis activating serine/threonine protein kinase, Ime2, the transcriptional regulators of glucose transporters, Mth1 and Std1, and the mitochondrial retrograde response inhibitor Mks1. Stabilization of these substrates lead to pleiotrophic phenotypic defects in grr1Δ strains including resistance to glucose repression, accumulation of grr1Δ cells in G2 and M phase of the cell cycle, sensitivity to osmotic stress, and resistance to divalent cations. However, many of these phenotypes are not reflected at the gene expression level. We conducted a quantitative genomic vii and proteomic comparison of 914 loci in a grr1Δ and wild-type strain grown to early log-phase in glucose media. These loci encompassed 16.7% of the Saccharomyces proteome of which 22.3% exhibited discordance between gene and protein expression. GO process enrichment analysis revealed that discordant loci were enriched in the processes of “trafficking”, “mitosis”, and “carbon/energy” metabolism. Here we show that these instances of discordance are biologically relevant and in fact reflect phenotypes of grr1Δ strains not evident at the transcriptional level. Additionally, through combined biochemical and network analysis of discordant loci among “carbon and energy metabolism” we were able to not only construct a model for central carbon metabolism in grr1Δ strains but also were able to elucidate a novel molecular event that may serve to regulate glucose repression of genes needed for respiration in response to changes in glucose concentration.Item Exosome-Mediated Crosstalk between Keratinocytes and Macrophages in Cutaneous Wound Healing(ACS, 2020-09) Zhou, Xiaoju; Brown, Brooke A.; Siegel, Amanda P.; El Masry, Mohamed S.; Zeng, Xuyao; Song, Woran; Das, Amitava; Khandelwal, Puneet; Clark, Andrew; Singh, Kanhaiya; Guda, Poornachander R.; Gorain, Mahadeo; Timsina, Lava; Xuan, Yi; Jacobson, Stephen C.; Novotny, Milos V.; Roy, Sashwati; Agarwal, Mangilal; Lee, Robert J.; Sen, Chandan K.; Clemmer, David E.; Ghatak, Subhadip; Surgery, School of MedicineBidirectional cell–cell communication involving exosome-borne cargo such as miRNA has emerged as a critical mechanism for wound healing. Unlike other shedding vesicles, exosomes selectively package miRNA by SUMOylation of heterogeneous nuclear ribonucleoproteinA2B1 (hnRNPA2B1). In this work, we elucidate the significance of exosome in keratinocyte–macrophage crosstalk following injury. Keratinocyte-derived exosomes were genetically labeled with GFP-reporter (Exoκ-GFP) using tissue nanotransfection (TNT), and they were isolated from dorsal murine skin and wound-edge tissue by affinity selection using magnetic beads. Surface N-glycans of Exoκ-GFP were also characterized. Unlike skin exosome, wound-edge Exoκ-GFP demonstrated characteristic N-glycan ions with abundance of low-base-pair RNA and was selectively engulfed by wound macrophages (ωmϕ) in granulation tissue. In vitro addition of wound-edge Exoκ-GFP to proinflammatory ωmϕ resulted in conversion to a proresolution phenotype. To selectively inhibit miRNA packaging within Exoκ-GFPin vivo, pH-responsive keratinocyte-targeted siRNA-hnRNPA2B1 functionalized lipid nanoparticles (TLNPκ) were designed with 94.3% encapsulation efficiency. Application of TLNPκ/si-hnRNPA2B1 to the murine dorsal wound-edge significantly inhibited expression of hnRNPA2B1 by 80% in epidermis compared to the TLNPκ/si-control group. Although no significant difference in wound closure or re-epithelialization was observed, the TLNPκ/si-hnRNPA2B1 treated group showed a significant increase in ωmϕ displaying proinflammatory markers in the granulation tissue at day 10 post-wounding compared to the TLNPκ/si-control group. Furthermore, TLNPκ/si-hnRNPA2B1 treated mice showed impaired barrier function with diminished expression of epithelial junctional proteins, lending credence to the notion that unresolved inflammation results in leaky skin. This work provides insight wherein Exoκ-GFP is recognized as a major contributor that regulates macrophage trafficking and epithelial barrier properties postinjury.