Biology subjects

Jablonski, K.

Publications and source records attributed to Jablonski, K..

5 recordsLinked to original sources

bioRxiv2022

Inhibition of extracellular vesicle-encapsulated miRNA produced by estrogen-mediated upregulation of cellular processing suppresses target organ inflammation in a humanized model of systemic lupus erythematosus

Background/PurposeDistinct, disease-associated intracellular miRNA (miR) expression profiles have been identified from peripheral blood mononuclear cells (PBMCs) of systemic lupus erythematous (SLE) patients. We have previously demonstrated novel estrogenic responses in PBMCs from SLE patients and discovered that estrogen lowers the threshold of immune cell activation to a greater extent in females, including significant upregulation of toll-like receptor (TLR)7 and TLR8 expression. TLR7 and TLR8 bind viral-derived single-stranded RNA to stimulate innate inflammatory responses, but recent studies have shown that miR-21, mir-29a, and miR-29b can also bind and activate these receptors when packaged and secreted in extracellular vesicles (EVs). ObjectiveThe objective of this study was to characterize the estrogen-mediated immunomodulatory effects of distinct EV-encapsulated miR profiles in SLE and evaluate the potential therapeutic approach of miR inhibition in a humanized mouse model. MethodsSLE patients meeting revised ACR guidelines and age/sex-matched healthy controls provided informed consent to participate in this IRB-approved study. Plasma-derived EVs were isolated by differential ultracentrifugation and quantified. PBMCs were isolated from whole blood and cultured in hormone free conditions before stimulation with 17{beta}-estradiol (estrogen; E2). RNA was isolated following E2 stimulation or EV isolation and bulk RNA-sequencing (RNAseq) reads were analyzed. Additionally, PBMCs from active SLE patients were injected into immunodeficient mice to produce chimeras. Prior to transfer, the PBMCs were incubated with liposomal EVs containing complementary locked nucleic acid (LNA) antagonists to miR-21, mir-29a, and miR-29b. After three weeks, blood was collected for both immunophenotyping and cytokine analysis and tissue was harvested for histopathological examination. ResultsEVs were found to be increased in the plasma of SLE patients and differentially expressed EV-derived miR profiles were detected compared to healthy controls, including miR-21, mir-29a, and miR-29b. E2 stimulation of PBMCs identified upregulated pathways involved in miR transcription/processing. Specifically, small RNA binding proteins and synthesis enzymes demonstrated significant signaling pathway association and upregulation with E2 treatment. Human immune cell subtypes were successfully recovered from whole blood of chimeric mice at similar levels with and without miR inhibition, but levels of human IL-6, IL-1{beta}, IL-4, and TNF- were significantly reduced by the LNA antagonists. Moreover, miR antagonists significantly reduced histopathological infiltrates in the small intestine, liver, and kidney, as demonstrated by H&E-stained tissue sections and immunohistochemistry measuring human CD3. ConclusionThese data suggest E2-mediated regulation of miR synthesis and demonstrate distinct EV-derived small RNA signatures representing SLE-associated biomarkers. Targeting upregulated EV-encapsulated miR signaling by antagonizing miRs that may bind to TLR7 and TLR8 reveals a novel therapeutic opportunity to suppress autoimmune-mediated inflammation and pathogenesis in SLE.

immunology↗

bioRxiv2022

Aromatase Inhibitor Induced Musculoskeletal Inflammation is Observed Independent of Oophorectomy in a Novel Mouse Model

BackgroundAromatase Inhibitors (AIs) block physiological estrogen production in peripheral tissues and are used clinically to reduce disease recurrences and improve overall survival rates in hormone receptor-positive breast cancer patients. However, half of patients taking these drugs develop aromatase inhibitor induced arthralgia (AIIA), which is characterized by severe pain and inflammation in various joints and the surrounding musculoskeletal tissue. While the pathophysiology is not currently understood, it has been proposed to be associated with systemic estrogen deficiency resulting from AI treatment. Since AIIA leads to suspension of therapy in 20-30% of patients, reducing AIIA incidence may provide sustained AI treatment and enhance long-term survival. ObjectiveIn order to establish a better understanding of disease pathology and to create a platform that can be used to explore future interventional strategies, our objective in this study was to design a novel animal model of AIIA. MethodsFemale BALB/C-Tg(NF{kappa}B-RE-luc)-Xen mice, which have a firefly luciferase cDNA reporter transgene under the regulation of NF{kappa}B binding sites, were oophorectomized and treated with AI (letrozole) by daily subcutaneous injections for 5 weeks. Control groups included oophorectomized mice receiving vehicle injections and non-oophorectomized mice treated with AI. Knee joints and surrounding muscle tissue were imaged on the BioSpec 94/30 micro-MRI. The primary weight-bearing joint (hind limb) was examined histopathologically and NF{kappa}B activity was measured by bioluminescent imaging. Serum was collected for cytokine analysis. Additionally, healthy human PBMCs were treated with letrozole, estrogen, or both, and RNA sequencing was performed at 36 hrs. ResultsBioluminescent imaging showed significantly enhanced NF{kappa}B activation with AI treatment in the hind limbs compared to controls receiving vehicle treatment. Moreover, analysis of knee joints and legs by MRI showed enhanced signal detection in the joint space and surrounding tissue following daily AI injections. Surprisingly, the enhanced MRI detection and NF{kappa}B activation was observed with AI treatment independent of the oophorectomy procedure. This indicates that the induction of musculoskeletal-directed inflammation by AI is not mediated by changes in physiological estrogen levels, which is contrary to proposed mechanisms of disease pathogenesis. Similarly, histopathological analysis showed tenosynovitis and musculoskeletal infiltrates in all mice receiving AI with or without oophorectomy. IHC analysis of the infiltrates demonstrated a predominantly macrophage-mediated inflammatory response with scattered CD4+ T cells. Additionally, serum cytokine levels of IL-2, IL-4, IL-6, and CXCL1 were significantly elevated in mice with AI treatment. RNA sequencing of human PBMCs after in vitro AI stimulation did not demonstrate an AI-specific gene expression pattern associated with immune system activation directly, suggesting that the pathogenesis of AIIA may be mediated through cells in other tissues in vivo. ConclusionsCollectively, these data establish a novel mouse model of AIIA and identify an estrogen-independent stimulation of disease pathology via AI-mediated induction. This suggests that the pathogenesis of AIIA may not be mediated by estrogen deficiency, as previously hypothesized, and indicates that AI-induced inflammation may not be regulated directly through a pathogenic mechanism initially derived from circulating mononuclear cells. Future studies aim to characterize this inflammatory mechanism in vivo with a focus on other cells, including macrophages, synovial cells and chondrocytes, to provide insight into putative therapeutic strategies directed at mitigating disease pathology.

immunology↗

bioRxiv2018

Effect of aboveground mass removal on toxicity of Geyers larkspur, with important implications for grazing management

The many species of larkspur (Delphinium spp. L.) are among the most dangerous poisonous plants on rangelands in the western United States, causing death losses estimated at 2-5% (up to 15%) per year for cattle grazing in larkspur habitat. Other effects, such as altered grazing management practices and consequent lost forage quantity and quality, are significant but poorly understood. Current best management practice recommendations are based on seasonal avoidance, with little evidence that this is practical or effective. Our ongoing research has presented evidence that instead it may be possible to manage grazing such that all cattle eat some larkspur, but none eat a fatal dose. This raises the question of the potential response of larkspur to being grazed. In this study we examine the response of Geyers larkspur (D. geyeri Greene) to two seasons of 25% or 75% aboveground plant mass removal. The 75% treatment led to significantly lower alkaloid concentrations (mg*g-1) and pools (mg per plant), while the 25% treatment had a lesser effect. Combined with lessons from previous studies, this indicates that Geyers larkspur plants subject to aboveground mass removal such as may occur via grazing can be expected to become significantly less dangerous to cattle. We suggest that the mechanisms for this reduction are both alkaloid removal and reduced belowground root mass, as significant evidence indicates that alkaloids are synthesized and stored in the roots. These results continue to build support for our theory that the solution to the seemingly intractable challenge of larkspur poisoning lies not in avoidance but in the skill of managers and the wisdom of herds.

ecology↗

bioRxiv2018

Predatory plants and patchy cows: modeling cattle interactions with toxic larkspur amid variable heterogeneity

The most common explanations for the evolution and persistence of herd behavior in large herbivores relate to decreased risk of predation. However, poisonous plants such as larkspur (Delphinium spp.) can present a threat comparable to predation. In the western United States, larkspur diminishes the economic and ecological sustainability of cattle production by killing valuable animals and restricting management options. Recommendations for mitigating losses have long focused on seasonal avoidance of pastures with larkspur, despite little evidence that this is practical or effective. Our ongoing research points to the cattle herd itself as the potential solution to this seemingly intractable challenge and suggests that larkspur and forage patchiness may drive deaths. In this paper, we present an agent-based model that incorporates neutral landscape models to assess the interaction between plant patchiness and herd behavior within the context of poisonous plants as predator and cattle as prey. The simulation results indicate that larkspur patchiness is indeed a driver of toxicosis and that highly cohesive herds can greatly reduce the risk of death in even the most dangerous circumstances. By placing the results in context with existing theories about the utility of herds, we demonstrate that grouping in large herbivores can be an adaptive response to patchily distributed poisonous plants. Lastly, our results hold significant management-relevant insight, both for cattle producers managing grazing in larkspur habitat and in general as a call to reconsider the manifold benefits of herd behavior among domestic herbivores.

ecology↗

bioRxiv2017

An agent-based model of cattle grazing toxic Geyer’s larkspur

By killing cattle and otherwise complicating management, the many species of larkspur (Delphinium spp.) present a serious, intractable, and complex challenge to livestock grazing management in the western United States. Among the many obstacles to improving our understanding of cattle-larkspur dynamics has been the difficulty of testing different grazing management strategies in the field, as the risk of dead animals is too great. Agent-based models (ABMs) provide an effective method of testing alternate management strategies without risk to livestock. ABMs are especially useful for modeling complex systems such as livestock grazing management, and allow for realistic bottom-up encoding of cattle behavior. Here, we introduce a spatially-explicit, behavior-based ABM of cattle grazing in a pasture with a dangerous amount of Geyers larkspur (D. geyeri). This model tests the role of herd cohesion and stocking density in larkspur intake, finds that both are key drivers of larkspur-induced toxicosis, and indicates that alteration of these factors within realistic bounds can mitigate risk. Crucially, the model points to herd cohesion, which has received little attention in the discipline, as playing an important role in lethal acute toxicosis. As the first ABM to model grazing behavior at realistic scales, this study also demonstrates the tremendous potential of ABMs to illuminate grazing management dynamics, including fundamental aspects of livestock behavior amidst ecological heterogeneity.

ecology↗