TY - JOUR A1 - Silwedel, Christine A1 - Hütten, Matthias C. A1 - Speer, Christian P. A1 - Härtel, Christoph A1 - Haarmann, Axel A1 - Henrich, Birgit A1 - Tijssen, Maud P. M. A1 - Alnakhli, Abdullah Ahmed A1 - Spiller, Owen B. A1 - Schlegel, Nicolas A1 - Seidenspinner, Silvia A1 - Kramer, Boris W. A1 - Glaser, Kirsten T1 - Ureaplasma-driven neonatal neuroinflammation: novel insights from an ovine model JF - Cellular and Molecular Neurobiology N2 - Ureaplasma species (spp.) are considered commensals of the adult genitourinary tract, but have been associated with chorioamnionitis, preterm birth, and invasive infections in neonates, including meningitis. Data on mechanisms involved in Ureaplasma-driven neuroinflammation are scarce. The present study addressed brain inflammatory responses in preterm lambs exposed to Ureaplasma parvum (UP) in utero. 7 days after intra-amniotic injection of UP (n = 10) or saline (n = 11), lambs were surgically delivered at gestational day 128–129. Expression of inflammatory markers was assessed in different brain regions using qRT-PCR and in cerebrospinal fluid (CSF) by multiplex immunoassay. CSF was analyzed for UP presence using ureB-based real-time PCR, and MRI scans documented cerebral white matter area and cortical folding. Cerebral tissue levels of atypical chemokine receptor (ACKR) 3, caspases 1-like, 2, 7, and C–X–C chemokine receptor (CXCR) 4 mRNA, as well as CSF interleukin-8 protein concentrations were significantly increased in UP-exposed lambs. UP presence in CSF was confirmed in one animal. Cortical folding and white matter area did not differ among groups. The present study confirms a role of caspases and the transmembrane receptors ACKR3 and CXCR4 in Ureaplasma-driven neuroinflammation. Enhanced caspase 1-like, 2, and 7 expression may reflect cell death. Increased ACKR3 and CXCR4 expression has been associated with inflammatory central nervous system (CNS) diseases and impaired blood–brain barrier function. According to these data and previous in vitro findings from our group, we speculate that Ureaplasma-induced caspase and receptor responses affect CNS barrier properties and thus facilitate neuroinflammation. KW - Ureaplasma parvum KW - CNS integrity KW - neonatal meningitis KW - preterm birth KW - immaturity KW - animal model Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-324285 VL - 43 IS - 2 ER - TY - JOUR A1 - Boeckel, Hannah A1 - Karsten, Christian M. A1 - Göpel, Wolfgang A1 - Herting, Egbert A1 - Rupp, Jan A1 - Härtel, Christoph A1 - Hartz, Annika T1 - Increased expression of anaphylatoxin C5a-receptor-1 in neutrophils and natural killer cells of preterm infants JF - International Journal of Molecular Sciences N2 - Preterm infants are susceptible to infection and their defense against pathogens relies largely on innate immunity. The role of the complement system for the immunological vulnerability of preterm infants is less understood. Anaphylatoxin C5a and its receptors C5aR1 and -2 are known to be involved in sepsis pathogenesis, with C5aR1 mainly exerting pro-inflammatory effects. Our explorative study aimed to determine age-dependent changes in the expression of C5aR1 and C5aR2 in neonatal immune cell subsets. Via flow cytometry, we analyzed the expression pattern of C5a receptors on immune cells isolated from peripheral blood of preterm infants (n = 32) compared to those of their mothers (n = 25). Term infants and healthy adults served as controls. Preterm infants had a higher intracellular expression of C5aR1 on neutrophils than control individuals. We also found a higher expression of C5aR1 on NK cells, particularly on the cytotoxic CD56\(^{dim}\) subset and the CD56\(^-\) subset. Immune phenotyping of other leukocyte subpopulations revealed no gestational-age-related differences for the expression of and C5aR2. Elevated expression of C5aR1 on neutrophils and NK cells in preterm infants may contribute to the phenomenon of “immunoparalysis” caused by complement activation or to sustained hyper-inflammatory states. Further functional analyses are needed to elucidate the underlying mechanisms. KW - preterm infants KW - C5a KW - C5aR1 KW - neutrophils KW - NK cells KW - innate immunity KW - sepsis Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-321196 SN - 1422-0067 VL - 24 IS - 12 ER - TY - JOUR A1 - Glaser, Kirsten A1 - Kern, David A1 - Speer, Christian P. A1 - Schlegel, Nicolas A1 - Schwab, Michael A1 - Thome, Ulrich H. A1 - Härtel, Christoph A1 - Wright, Clyde J. T1 - Imbalanced inflammatory responses in preterm and term cord blood monocytes and expansion of the CD14\(^+\)CD16\(^+\) subset upon toll-like receptor stimulation JF - International Journal of Molecular Sciences N2 - Developmentally regulated features of innate immunity are thought to place preterm and term infants at risk of infection and inflammation-related morbidity. Underlying mechanisms are incompletely understood. Differences in monocyte function including toll-like receptor (TLR) expression and signaling have been discussed. Some studies point to generally impaired TLR signaling, others to differences in individual pathways. In the present study, we assessed mRNA and protein expression of pro- and anti-inflammatory cytokines in preterm and term cord blood (CB) monocytes compared with adult controls stimulated ex vivo with Pam3CSK4, zymosan, polyinosinic:polycytidylic acid, lipopolysaccharide, flagellin, and CpG oligonucleotide, which activate the TLR1/2, TLR2/6, TLR3, TLR4, TLR5, and TLR9 pathways, respectively. In parallel, frequencies of monocyte subsets, stimulus-driven TLR expression, and phosphorylation of TLR-associated signaling molecules were analyzed. Independent of stimulus, pro-inflammatory responses of term CB monocytes equaled adult controls. The same held true for preterm CB monocytes—except for lower IL-1β levels. In contrast, CB monocytes released lower amounts of anti-inflammatory IL-10 and IL-1ra, resulting in higher ratios of pro-inflammatory to anti-inflammatory cytokines. Phosphorylation of p65, p38, and ERK1/2 correlated with adult controls. However, stimulated CB samples stood out with higher frequencies of intermediate monocytes (CD14\(^+\)CD16\(^+\)). Both pro-inflammatory net effect and expansion of the intermediate subset were most pronounced upon stimulation with Pam3CSK4 (TLR1/2), zymosan (TR2/6), and lipopolysaccharide (TLR4). Our data demonstrate robust pro-inflammatory and yet attenuated anti-inflammatory responses in preterm and term CB monocytes, along with imbalanced cytokine ratios. Intermediate monocytes, a subset ascribed pro-inflammatory features, might participate in this inflammatory state. KW - neonatal immunology KW - inflammation KW - preterm infants KW - monocytes KW - cord blood KW - monocyte subsets KW - cytokines KW - Toll-like receptor signaling Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-311056 SN - 1422-0067 VL - 24 IS - 5 ER -