Biology subjects

Larson, K. Y.

Publications and source records attributed to Larson, K. Y..

3 recordsLinked to original sources

bioRxiv2024

IL15/IL15Rα complex induces an anti-tumor immune response following radiation therapy only in the absence of Tregs and fails to induce expansion of progenitor TCF1+ CD8 T cells

BackgroundThis work seeks to understand whether IL15-incorporating treatments improve response to radiotherapy and uncover mechanistic rationale for overcoming resistance to IL15 agonism using novel therapeutic combinations. Experimental DesignOrthotopic tumor models of PDAC were used to determine response to treatment. IL15-/- and Rag1-/- mouse models were employed to determine dependence on IL15 and CTLs, respectively. Flow cytometry was used to assess immune cell frequency and activation state. Phospho-proteomic analyses were used to characterize intracellular signaling pathways. ResultsWe show that the combination of radiation therapy (RT) and an IL15/IL15Ra fusion complex (denoted IL15c) fails to confer anti-tumor efficacy; however, a CD8-driven anti-tumor immune response is elicited with the concurrent administration of an aCD25 Treg-depleting antibody. Using IL15-/- and Rag1-/- mice, we demonstrate that response to RT + IL15c + aCD25 is dependent on both IL15 and CTLs. Furthermore, despite an equivalent survival benefit following treatment with RT + IL15c + aCD25 and combination RT + PD1-IL2v, a novel immunocytokine with PD-1 and IL2R{beta}{gamma} binding domains, CTL immunophenotyping and phospho-proteomic analysis of intracellular metabolites showed significant upregulation of activation and functionality in CD8 T cells treated with RT + PD1-IL2v. Finally, we show the immunostimulatory response to RT + PD1-IL2v is significantly diminished with a concurrent lack of TCF+ CD8 T cell generation in the absence of functional IL15 signaling. ConclusionsOur results are illustrative of a mechanism wherein unimpeded effector T cell activation through IL2R{beta} signaling and Treg inhibition are necessary in mediating an anti-tumor immune response.

cancer biology↗

bioRxiv2024

Discerning Specific Thrombolytic Activities and Blood Clot Degradomes of Diverse Snake Venoms with Untargeted Peptidomics

Identification and characterization of snake venom toxins that interfere with hemostasis have important implications for the treatment of snake envenomation, the bioprospecting of therapeutically useful molecules, and the development of research tools for investigating hematologic disorders. Many venoms have been shown to possess thrombolytic activity. However, it remains unclear if actions on other clot-stabilizing proteins beyond fibrin chains contribute significantly to venom-induced thrombolysis because the clot-wide targets of venom proteases and the mechanisms responsible for thrombolysis are not well understood. Here, we utilize a high-throughput time-based thrombolysis assay in combination with untargeted peptidomics to provide comprehensive insight into the effects of venom from six snake species on blood clot degradation. We compare thrombolytic profiles across venoms with variable levels of proteases and generate venom-specific fingerprints of cleavage specificity. We also compare the specific effects of venoms that possess a range of thrombolytic activity on fibrin subunits and other clot-bound proteins involved in clot structure. Venoms with higher thrombolytic activity demonstrated an enhanced ability to target multiple sites across fibrin chains critical to clot stability and structure, as well as clot-stabilizing proteins including fibronectin and vitronectin. Collectively, this study significantly expands our understanding of the thrombolytic and fibrinolytic effects of snake venom by determining the full suite of clot-specific venom targets that are involved in clot formation and stability.

pharmacology and toxicology↗

bioRxiv2023

ASSESSING TARGET SPECIFICITY OF THE SMALL MOLECULE INHIBITOR MARIMASTAT TO SNAKE VENOM TOXINS: A NOVEL APPLICATION OF THERMAL PROTEOME PROFILING

New treatments that circumvent the pitfalls of traditional antivenom therapies are critical to address the problem of snakebite globally. Numerous snake venom toxin inhibitors have shown promising cross-species neutralization of medically significant venom toxins in vivo and in vitro. The development of high-throughput approaches for the screening of such inhibitors could accelerate their identification, testing, and implementation, and thus holds exciting potential for improving the treatments and outcomes of snakebite envenomation worldwide. Energetics-based proteomic approaches, including Thermal Proteome Profiling (TPP) and Proteome Integral Solubility Alteration (PISA), assays represent "deep proteomics" methods for high throughput, proteome-wide identification of drug targets and ligands. In the following study, we apply TPP and PISA methods to characterize the interactions between venom toxin proteoforms in Crotalus atrox (Western Diamondback Rattlesnake) and the snake venom metalloprotease (SVMP) inhibitor marimastat. We investigate its venom proteome-wide effects and characterize its interactions with specific SVMP proteoforms, as well as its potential targeting of non-SVMP venom toxin families. We also compare the performance of PISA thermal window and soluble supernatant with insoluble precipitate using two inhibitor concentrations, providing the first demonstration of the utility of a sensitive high-throughput PISA-based approach to assess the direct targets of small molecule inhibitors for snake venom.

biochemistry↗