Product Citations: 2

Distinct Functional States of Neutrophils by Actin Disassembly and NF-kB/STAT3 Signaling

Preprint on BioRxiv : the Preprint Server for Biology on 17 July 2023 by Heineken, N., Schumacher, J. C., et al.

Polymorphonuclear neutrophils (PMNs) can differentiate into distinct states, which can either exacerbate or resolve inflammation. Our study shows that mice challenged with TLR agonists exhibited PMN differentiation along two major paths characterized by the expression of CCR5 or PD-L1. Similar differentiation was observed in the blood of severe COVID-19 patients and the synovial fluid of osteoarthritis patients. Prolonged in vitro priming of human PMNs modeled the differentiation paths. Actin disassembly favored CCR5 upregulation, while NF-kB activation stabilized the actin cytoskeleton and suppressed the development of CCR5 + PMNs. Additionally, PD-L1 upregulation was triggered by STAT3 signaling and NF-kB activation. Functionally, CCR5 expressing PMNs were pro-NETotic, while PD-L1 + PMNs showed immunosuppressive functions by inhibiting T cell proliferation via PD1. Together, PMN differentiation depended on the priming conditions, and the balance between actin disassembly and NF-kB/STAT3 activation translated the present micro-milieu into phenotypic and functional diversification of PMNs. Synopsis Neutrophils underwent phenotypical and functional diversification both in vivo and in vitro . Actin disassembly led to the generation of CCR5 high neutrophils with increased spontaneous NETosis, whereas NF-kB and STAT3 induced PD-L1 expression with T-cell suppressive properties as a deviation from the default pathway. PMN of mice challenged with TLR agonists develop two distinct phenotypes, CCR5 high and PD-L1 high . CCR5 and PD-L1-defined neutrophil phenotypes were found in blood of patients with severe COVID-19 and in the synovial fluid of osteoarthritis patients. In vitro priming induced a similar bifurcation of PMN phenotypes marked by either CCR5 or PD-L1. Actin disassembly preceded canonical development of CCR5 + PMN. NF-kB halted actin disassembly by LPL regulation. During neutrophil priming, STAT3 aided NF-kB in the expression of PD-L1. Graphical abstract

  • Cell Biology

CD49d Treg cells with high suppressive capacity are remarkably less efficient on activated CD45RA- than on naive CD45RA+ Teff cells.

In Cellular Physiology and Biochemistry on 26 July 2014 by Kraczyk, B., Remus, R., et al.

Impairment of regulatory T cells (Tregs) in common autoimmune diseases seems likely. However, the extent of Treg deficiency (number, function) or differential susceptibility of T effector cells (Teffs) to suppression is not completely understood. We hypothesize that even in healthy individuals both cell populations are heterogeneous and differ in their suppressive capability and their susceptibility to suppression.
Lymphocytes were enriched by MACS for CD4(+)CD25(+) Tregs or CD4(+)CD25(-) Teffs. After multicolour staining (anti-CD25, anti-CD127, anti-CD49d or anti-CD45RA) highly purified Treg and Teff subpopulations were collected by FACS. Functional capacity of Tregs or suppressive susceptibility of Teffs was analyzed in an in vitro assay.
When CD4(+)CD25(high)CD127(-/low) CD49d(-) Tregs were tested on naive CD4(+)CD127(+)CD25(-)CD45RA(+) Teffs (93.8 %) suppression was almost complete, while the suppressive capacity of CD4(+)CD25(high)CD127(-/low) CD49d(+) Tregs was significantly less (71.8 %). Suppressive activity was low when CD4(+)CD25(high)CD127(-/low) CD49d(+) Tregs were analyzed on CD4(+)CD127(+)CD25(-)CD45RA(-) Teffs (48.7%).
Although CD49d(+) Tregs are functional, the suppressive capacity is significantly lower compared to CD49d(-) Tregs. CD45RA(+) Teffs can be completely suppressed, while CD45RA(-) Teffs display relative resistance. Phenotypic and functional heterogeneity of Tregs as well as Teffs has to be considered when analyzing deficiencies in immune regulation.
© 2014 S. Karger AG, Basel.

  • Immunology and Microbiology
View this product on CiteAb