Biology subjects

Mobley, J. A.

Publications and source records attributed to Mobley, J. A..

7 recordsLinked to original sources

bioRxiv2026

Hyaluronic Acid Plays Differential Molecular Weight and Concentration Dependent Pathway Centric Changes to Human Lung Derived Microvascular Endothelial Cells in Culture

BackgroundHyaluronan (HA) is a major extracellular matrix glycosaminoglycan that regulates vascular integrity and immune signaling in the lung. Its biological effects are strongly size-dependent, with high-molecular-weight HA (HMW-HA) generally protective and low-molecular-weight HA (LMW-HA) pro-inflammatory. However, how different HA sizes and concentrations globally remodel endothelial cell signaling remains poorly understood. MethodsHuman lung microvascular endothelial cells (HULEC-5a) were treated with physiologic (200 ng/mL) or supraphysiologic (1 {micro}g/mL) concentrations of LMW-, medium-molecular-weight (MMW-), or HMW-HA. Cell viability was confirmed by LDH assay. Quantitative proteomics with downstream Ingenuity Pathway Analysis (IPA) was used to profile HA-induced signaling networks. ResultsProteomic analysis revealed a conserved HA-response signature across all conditions involving cell cycle regulation, senescence, and immune modulation, with distinct size-and dose-dependent differences. At supraphysiologic concentrations, HMW-HA suppressed proliferative and inflammatory pathways, consistent with a protective, quiescent phenotype. LMW-HA induced the broadest stress-associated proteomic changes, consistent with its role as a damage-associated molecular pattern. Unexpectedly, physiologic MMW-HA elicited the strongest responses, driving metabolic and cytoskeletal pathways including insulin signaling and Rho GTPase activity. Network analysis highlighted 176 overlapping pathways across HA treatments, with unique contributions of LMW- and HMW-HA to stress- versus barrier-stabilizing signaling, respectively. ConclusionHA is not a passive structural molecule but an active regulator of endothelial signaling, with effects shaped by both molecular weight and concentration. Our findings identify a distinct role for MMW-HA at physiologic levels and highlight how HA fragmentation and accumulation may contribute to endothelial dysfunction in lung injury, with implications for targeted HA-based therapies.

cell biology↗

bioRxiv2025

Venom vesicles from the parasitoid Ganaspis hookeri facilitate venom protein entry into host immune cells

The parasitoid wasp Ganaspis hookeri infects Drosophila melanogaster larvae, laying an egg and injecting venom directly into the host body cavity. While infected hosts mount an immune response in an attempt to eliminate the parasitoid egg, parasitoid venom proteins act to inhibit these host immune responses and manipulate host physiology to ensure infection success. A key immune suppressive venom protein in G. hookeri is a venom- specific isoform of the SERCA (Sarco/endoplasmic reticulum Ca2+-ATPase) calcium pump. However, SERCA is a large hydrophobic protein, and the mechanism by which it and other venom proteins are transported into the host is not well understood. We used a variety of biophysical, biochemical, and cell biological approaches to assess the properties of G. hookeri venom. Electronic microscopy and nanoparticle tracking analysis revealed the presence of venom vesicles as a putative transport mechanism. We used tunable resistive pulse sensing (TRPS) to biophysically characterize these vesicles, and our TRPS data suggest G. hookeri venom is composed of multiple vesicle types that are distinguishable by size, zeta potential, and density. Finally, we fluorescently labeled venom vesicles to test for entry into host immune cells. We observed that these vesicles interact with immune cells membranes and are internalized into the cell. Our data support a model in which G. hookeri venom proteins, including SERCA, are packaged into an array of venom vesicles, and transported into host cells for immune suppression.

biochemistry↗

bioRxiv2024

Decreased Extracellular Vesicle Vasorin in Severe Preeclampsia Plasma Mediates Endothelial Dysfunction

BackgroundPreeclampsia (PE) is a serious pregnancy complication affecting 5-8% of pregnancies globally. It is a leading cause of maternal and neonatal morbidity and mortality. Despite its prevalence, the underlying mechanisms of PE remain unclear. This study aimed to determine the potential role of vasorin (VASN) in PE pathogenesis by investigating its levels in extracellular vesicles (EV) and its effects on vascular function. Methods & ResultsWe conducted unbiased proteomics on urine-derived EV from severe PE (sPE) and normotensive pregnant women (NTP), identifying differential protein abundances. Out of one hundred and twenty proteins with [≥] {+/-}1.5-fold regulation at P<0.05 between sPE and NTP, we focused on Vasorin (VASN), which is downregulated in sPE in urinary EV, in plasma EV and in the placenta and is a known regulator of vascular function. We generated EV with high VASN content from both human and murine placenta explants (Plex EV), which recapitulated disease-state-dependent effects on vascular function observed when treating murine aorta rings (MAR) or human aortic endothelial cells (HAEC) with murine or human plasma-derived EV. In normal murine pregnancy, VASN increases with gestational age (GA), and VASN is decreased in plasma EV, in placenta tissue and in Plex EV after intravenous administration of adenovirus encoding short FMS-like tyrosine kinase 1 (sFLT-1), a murine model of PE (murine-PE). VASN is decreased in plasma EV, in placenta tissue and in EV isolated from conditioned media collected from placenta explants (Plex EV) in patients with sPE as compared to NTP. Human sPE and murine-PE plasma EV and Plex EV impair migration, tube formation, and induces apoptosis in human aortic endothelial cells (HAEC) and inhibit acetylcholine-induced vasorelaxation in murine vascular rings (MAR). VASN over-expression counteracts the effects of sPE EV treatment in HAEC and MAR. RNA sequencing revealed that over-expression or knock down of VASN in HAEC results in contrasting effects on transcript levels of hundreds of genes associated with vasculogenesis, endothelial cell proliferation, migration and apoptosis. ConclusionsThe data suggest that VASN, delivered to the endothelium via EV, regulates vascular function and that the loss of EV VASN may be one of the mechanistic drivers of PE. CLINICAL PERSPECTIVEWhat is New O_LIVASN in circulating plasma EV in sPE is reduced compared with VASN content in plasma EV of gestational age-matched pregnant women. C_LIO_LIVASN is encapsulated and transported in EV and plays a pro-angiogenic role during pregnancy. C_LIO_LIVASN should be explored both for its pro-angiogenic mechanistic role and as a novel biomarker and potential predictive diagnostic marker for the onset and severity of PE. C_LI What Are the Clinical Implications? O_LIVASN plays a role in maintaining vascular health and the normal adaptive cardiovascular response in pregnancy. A decrease of VASN is observed in sPE patients contributing to cardiovascular maladaptation. C_LIO_LIStrategies to boost diminished VASN levels and/or to pharmacologically manipulate mechanisms downstream of VASN may be explored for potential therapeutic benefit in PE. C_LIO_LIThe decrease in EV-associated VASN could potentially be used as a (predictive) biomarker for PE. C_LI

molecular biology↗

bioRxiv2023

Hemopexin Reverses Activation of Lung eIF2a and Decreases Mitochondrial Injury in Chlorine Exposed Mice

We assessed the mechanisms by which non-encapsulated heme, released in the plasma of mice post exposure to chlorine (Cl2) gas, resulted in the initiation and propagation of acute lung injury. We exposed adult C57BL/6 male and female to Cl2 (500 ppm for 30 min) in environmental chambers and returned them to room air and injected them intramuscularly with a single dose of human hemopexin (hHPX; 5 {micro}g/ g BW), the most efficient scavenger of heme, 30-60 min post exposure. Concentrations of hHPX in plasma of air and Cl2 exposed mice were 9081{+/-}900 vs. 1879{+/-} 293 at 6 h and 2966{+/-}463 vs. 1555{+/-}250 at 50 h post injection (ng/ml; X{+/-}1 SEM=3; p<0.01). Cl2 exposed mice developed progressive acute lung injury post exposure characterized by increased concentrations of plasma heme, marked inflammatory response, respiratory acidosis and increased concentrations of plasma proteins in the alveolar space. Injection of hHPX decreased the onset of acute lung injury at 24 h post exposure; mean survival, for the saline and hHPX groups were 40 vs. 80% (P<0.001) at 15 d post exposure. Non-supervised global proteomics analysis of mouse lungs at 24 h post exposure, revealed the upregulation of 92 and downregulation of 145 lung proteins. Injection of hHPX at one h post exposure moderated the Cl2 induced changes in eighty-three of these 237 lung proteins. System biology analysis of the global proteomics data showed that hHPX reversed changes in mitochondrial dysfunction and elF2 and integrin signaling. Western blot analysis of lung tissue showed significant increase of phosphorylated elF2 at 24 h post exposure in vehicle treated mice but normal levels in those injected with hHPX. Similarly, RT-PCR analysis of lung tissue showed that hHPX reversed the onset of mtDNA lesions. A form of recombinant human hemopexin generated in tobacco plants was equally effective in reversing acute lung and mtDNA injury. The results of this study offer new insights as to the mechanisms by which exposure to Cl2 results in acute lung injury and to the therapeutic effects of hemopexin.

physiology↗

bioRxiv2022

The SARS-CoV-2 Spike S1 Protein Induces Global Proteomic Changes in ATII-Like Rat L2 Cells that are Attenuated by Hyaluronan

The COVID-19 pandemic continues to impose a major impact on global health and economy since its identification in early 2020, causing significant morbidity and mortality worldwide. Caused by the SARS-CoV-2 virus, along with a growing number of variants that have been characterized to date, COVID-19 has led to 571,198,904 confirmed cases, and 6,387,863 deaths worldwide (as of July 15th, 2022). Despite tremendous advances in our understanding of COVID19 pathogenesis, the precise mechanism by which SARS-CoV2 causes epithelial injury is incompletely understood. In this current study, robust application of global-discovery proteomics applications combined with systems biology analysis identified highly significant induced changes by the Spike S1 protein of SARS-CoV-2 in an ATII-like Rat L2 cells that include three significant network hubs: E2F1, CREB1/ RelA, and ROCK2/ RhoA. Separately, we found that pre-treatment with High Molecular Weight Hyaluronan (HMW-HA), greatly attenuated the S1 effects. Immuno-targeted studies carried out on E2F1 and Rock2/ RhoA induction and kinase-mediated activation, in addition to cell cycle measurements, validated these observations. Taken as a whole, our discovery proteomics and systems analysis workflow, combined with standard immuno-targeted and cell cycle measurements revealed profound and novel biological changes that contribute to our current understanding of both Spike S1 and Hyaluronan biology. This data shows that the Spike S1 protein may contribute to epithelial injury induced by SARS-CoV-2. In addition, our work supports the potential benefit of HMW-HA in ameliorating SARS CoV2 induced cell injury.

systems biology↗

bioRxiv2021

Mesenchymal Stromal Cell Aging Impairs the Self-Organizing Capacity of Lung Alveolar Epithelial Stem Cells

Multicellular organisms maintain structure and function of tissues/organs through emergent, self-organizing behavior. In this report, we demonstrate a critical role for lung mesenchymal stromal cell (L-MSC) aging in determining the capacity to form 3-dimentional organoids or "alveolospheres " with type 2 alveolar epithelial cells (AEC2s). In contrast to L-MSCs from aged mice, young L-MSCs support the efficient formation of alveolospheres when co-cultured with young or aged AEC2s. Aged L-MSCs demonstrated features of cellular senescence, altered bioenergetics, and a senescence-associated secretory profile (SASP). The reactive oxygen species generating enzyme, NADPH oxidase 4 (Nox4), was highly activated in aged L-MSCs and Nox4 downregulation was sufficient to, at least partially, reverse this age-related energy deficit, while restoring the self-organizing capacity of alveolospheres. Together, these data indicate a critical role for cellular bioenergetics and redox homeostasis in an organoid model of self-organization, and supports the concept of thermodynamic entropy in aging biology.

cell biology↗

bioRxiv2019

Phosphoprotein-based Biomarkers as Predictors for Cancer Therapy

Disparities in cancer patient responses have prompted widespread searches to identify differences in sensitive vs. non-sensitive populations and form the basis of personalized medicine. This customized approach is dependent upon the development of pathway-specific therapeutics in conjunction with biomarkers that predict patient responses. Here, we show that Cdk5 drives growth in subgroups of human patients with multiple types of neuroendocrine neoplasms. Phosphoproteomics and high throughput screening identified novel phosphorylation sites downstream of Cdk5. These phosphorylation events serve as biomarkers of Cdk5 activity and effectively pinpoint Cdk5-driven tumors. Toward achieving targeted therapy, we demonstrate that mouse models of neuroendocrine cancer are responsive to selective Cdk5 inhibitors and biomimetic nanoparticles are effective vehicles for enhanced tumor targeting and reduction of drug toxicity. Finally, we show that biomarkers of Cdk5-dependent tumors effectively predict response to anti-Cdk5 therapy in patient-derived xenografts. Thus, a phosphoprotein-based diagnostic assay combined with Cdk5-targeted therapy is a rational treatment approach for neuroendocrine malignancies.

cancer biology↗