The Peroxisome Proliferator Activated Receptor‐γ Pioglitazone Improves Vascular Function and Decreases Disease Activity in Patients With Rheumatoid Arthritis

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139088/1/jah3374.pd

Increased Adhesive Potential of Antiphospholipid Syndrome Neutrophils Mediated by β2 Integrin Macâ 1

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153125/1/art41057.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153125/2/art41057_am.pd

Dysfunction of endothelial progenitor cells is associated with the type I IFN pathway in patients with polymyositis and dermatomyositis

Objective. Alterations in phenotype and function of endothelial progenitor cells (EPCs) have been associated with poor vascular outcomes and impaired vascular repair in various conditions. Our hypothesis was that patients with PM and DM have dysregulation of EPCs driven by type I IFN and IL-18 similar to other autoimmune diseases. Methods. Quantification of circulating EPCs was performed by flow cytometry in patients with PM/DM and matched healthy controls. The ability of EPCs to differentiate into mature endothelial cells was investigated by light and fluorescence microscopy quantification in the presence or absence of PM/DM or control serum, neutralizing antibodies to type I IFN receptor or IL-18. Serum type I IFN activity was quantified by induction of type I IFN-inducible genes in HeLa cells. Circulating IL-18 concentrations were assessed by ELISA. Results. Circulating EPCs were significantly lower in PM/DM patients compared with controls. PM/DM EPCs displayed a decreased capacity to differentiate into mature endothelial cells and PM/DM serum significantly inhibited differentiation of control EPCs. This effect was reversed in the majority of samples with neutralizing antibodies to IL-18 or to type I IFN receptor or by a combination of these antibodies. Patients with associated impairments in EPC function had higher type I IFN serum activity. Conclusion. PM/DM is associated with dysregulation of EPC phenotype and function that may be attributed, at least in part, to aberrant IL-18 and type I IFN pathways. The implication of these vasculopathic findings for disease prognosis and complications remains to be determined

In Vivo Role of Neutrophil Extracellular Traps in Antiphospholipid Antibody–Mediated Venous Thrombosis

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136296/1/art39938_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136296/2/art39938.pd

Antimicrobial Microwebs of DNA–Histone Inspired from Neutrophil Extracellular Traps

Neutrophil extracellular traps (NETs) are decondensed chromatin networks released by neutrophils that can trap and kill pathogens but can also paradoxically promote biofilms. The mechanism of NET functions remains ambiguous, at least in part, due to their complex and variable compositions. To unravel the antimicrobial performance of NETs, a minimalistic NET‐like synthetic structure, termed “microwebs,” is produced by the sonochemical complexation of DNA and histone. The prepared microwebs have structural similarity to NETs at the nanometer to micrometer dimensions but with well‐defined molecular compositions. Microwebs prepared with different DNA to histone ratios show that microwebs trap pathogenic Escherichia coli in a manner similar to NETs when the zeta potential of the microwebs is positive. The DNA nanofiber networks and the bactericidal histone constituting the microwebs inhibit the growth of E. coli. Moreover, microwebs work synergistically with colistin sulfate, a common and a last‐resort antibiotic, by targeting the cell envelope of pathogenic bacteria. The synthesis of microwebs enables mechanistic studies not possible with NETs, and it opens new possibilities for constructing biomimetic bacterial microenvironments to better understand and predict physiological pathogen responses.Microwebs with bacteria trapping and killing functions are designed to mimic neutrophil extracellular traps—an immune defense weapon to fight against invading pathogens. The composition–structure–function relationship of the synthetic structure is discussed, and the collaborative action between microwebs and antibiotics allows better elimination of pathogenic bacteria, Escherichia coli.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149216/1/adma201807436-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149216/2/adma201807436_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149216/3/adma201807436.pd

Visualization of Nuclease- and Serum-Mediated Chromatin Degradation with DNA–Histone Mesostructures

This study analyzed the nuclease- and serum-driven degradation of millimeter-scale, circular DNA–histone mesostructures (DHMs). DHMs are bioengineered chromatin meshes of defined DNA and histone compositions designed as minimal mimetics of physiological extracellular chromatin structures, such as neutrophil extracellular traps (NETs). Taking advantage of the defined circular shape of the DHMs, an automated time-lapse imaging and image analysis method was developed and used to track DHM degradation and shape changes over time. DHMs were degraded well by 10 U/mL concentrations of deoxyribonuclease I (DNase I) but not by the same level of micrococcal nuclease (MNase), whereas NETs were degraded well by both nucleases. These comparative observations suggest that DHMs have a less accessible chromatin structure compared to NETs. DHMs were degraded by normal human serum, although at a slower rate than NETs. Interestingly, time-lapse images of DHMs revealed qualitative differences in the serum-mediated degradation process compared to that mediated by DNase I. Importantly, despite their reduced susceptibility to degradation and compositional simplicity, the DHMs mimicked NETs in being degraded to a greater extent by normal donor serum compared to serum from a lupus patient with high disease activity. These methods and insights are envisioned to guide the future development and expanded use of DHMs, beyond the previously reported antibacterial and immunostimulatory analyses, to extracellular chromatin-related pathophysiological and diagnostic studies

Visualization of Nuclease- and Serum-Mediated Chromatin Degradation with DNA–Histone Mesostructures

This study analyzed the nuclease- and serum-driven degradation of millimeter-scale, circular DNA–histone mesostructures (DHMs). DHMs are bioengineered chromatin meshes of defined DNA and histone compositions designed as minimal mimetics of physiological extracellular chromatin structures, such as neutrophil extracellular traps (NETs). Taking advantage of the defined circular shape of the DHMs, an automated time-lapse imaging and image analysis method was developed and used to track DHM degradation and shape changes over time. DHMs were degraded well by 10 U/mL concentrations of deoxyribonuclease I (DNase I) but not by the same level of micrococcal nuclease (MNase), whereas NETs were degraded well by both nucleases. These comparative observations suggest that DHMs have a less accessible chromatin structure compared to NETs. DHMs were degraded by normal human serum, although at a slower rate than NETs. Interestingly, time-lapse images of DHMs revealed qualitative differences in the serum-mediated degradation process compared to that mediated by DNase I. Importantly, despite their reduced susceptibility to degradation and compositional simplicity, the DHMs mimicked NETs in being degraded to a greater extent by normal donor serum compared to serum from a lupus patient with high disease activity. These methods and insights are envisioned to guide the future development and expanded use of DHMs, beyond the previously reported antibacterial and immunostimulatory analyses, to extracellular chromatin-related pathophysiological and diagnostic studies

Dysfunction of endothelial progenitor cells is associated with the type I IFN pathway in patients with polymyositis and dermatomyositis

Objective. Alterations in phenotype and function of endothelial progenitor cells (EPCs) have been associated with poor vascular outcomes and impaired vascular repair in various conditions. Our hypothesis was that patients with PM and DM have dysregulation of EPCs driven by type I IFN and IL-18 similar to other autoimmune diseases. Methods. Quantification of circulating EPCs was performed by flow cytometry in patients with PM/DM and matched healthy controls. The ability of EPCs to differentiate into mature endothelial cells was investigated by light and fluorescence microscopy quantification in the presence or absence of PM/DM or control serum, neutralizing antibodies to type I IFN receptor or IL-18. Serum type I IFN activity was quantified by induction of type I IFN-inducible genes in HeLa cells. Circulating IL-18 concentrations were assessed by ELISA. Results. Circulating EPCs were significantly lower in PM/DM patients compared with controls. PM/DM EPCs displayed a decreased capacity to differentiate into mature endothelial cells and PM/DM serum significantly inhibited differentiation of control EPCs. This effect was reversed in the majority of samples with neutralizing antibodies to IL-18 or to type I IFN receptor or by a combination of these antibodies. Patients with associated impairments in EPC function had higher type I IFN serum activity. Conclusion. PM/DM is associated with dysregulation of EPC phenotype and function that may be attributed, at least in part, to aberrant IL-18 and type I IFN pathways. The implication of these vasculopathic findings for disease prognosis and complications remains to be determined. <br/

SARS-CoV-2 Spike Protein S1-Mediated Endothelial Injury and Pro-Inflammatory State Is Amplified by Dihydrotestosterone and Prevented by Mineralocorticoid Antagonism

Men are disproportionately affected by the coronavirus disease-2019 (COVID-19), and face higher odds of severe illness and death compared to women. The vascular effects of androgen signaling and inflammatory cytokines in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-mediated endothelial injury are not defined. We determined the effects of SARS-CoV-2 spike protein-mediated endothelial injury under conditions of exposure to androgen dihydrotestosterone (DHT) and tumor necrosis factor-a (TNF-α) and tested potentially therapeutic effects of mineralocorticoid receptor antagonism by spironolactone. Circulating endothelial injury markers VCAM-1 and E-selectin were measured in men and women diagnosed with COVID-19. Exposure of endothelial cells (ECs) in vitro to DHT exacerbated spike protein S1-mediated endothelial injury transcripts for the cell adhesion molecules E-selectin, VCAM-1 and ICAM-1 and anti-fibrinolytic PAI-1 (p &lt; 0.05), and increased THP-1 monocyte adhesion to ECs (p = 0.032). Spironolactone dramatically reduced DHT+S1-induced endothelial activation. TNF-α exacerbated S1-induced EC activation, which was abrogated by pretreatment with spironolactone. Analysis from patients hospitalized with COVID-19 showed concordant higher circulating VCAM-1 and E-Selectin levels in men, compared to women. A beneficial effect of the FDA-approved drug spironolactone was observed on endothelial cells in vitro, supporting a rationale for further evaluation of mineralocorticoid antagonism as an adjunct treatment in COVID-19