Celik, I. | bioRxiv Science

bioRxiv2026

A Broad-Spectrum Chemokine Inhibitor Prevents Preterm Labor in Mice by Supressing Inflammation Induced by Intra-Amniotic Injection of Interleukin-1 alpha

Preterm birth (PTB) is a leading cause of perinatal and infant mortality worldwide. PTB can be induced by systemic maternal or intra-uterine infection or by sterile intra-amniotic inflammation driven by alarmins such as interleukin-1 (IL-1). We reported earlier that a Broad-Spectrum Chemokine Inhibitor (BSCI) prevented PTB in murine and non-human primate models of infection-mediated preterm labor. Here, we investigated whether BSCI can prevent PTB in pregnant C57BL/6 mice following ultrasound-guided intra-amniotic injection of IL-1 (400 ng per sac) on gestational day (GD)16.5. Half the mice received BSCI (10 mg/kg, intravenous daily) beginning GD15.5 and through to term. The impact of IL-1 alone or IL-1 plus BSCI was assessed on (i) injection-to-delivery interval, fetal survival, placental and neonatal weight; (ii) cytokine and chemokine levels in maternal plasma and amniotic fluid and inflammatory gene expression in maternal and fetal tissues (Real-Time RT-qPCR); (iii) global transcriptomic profiling of myometrial tissues at 2 and 24 hrs (RNA sequencing) together with examination of myometrial chromatin accessibility (Assay for transposase accessible chromatin sequencing) at 24 hrs; (iv) uterine leukocyte infiltration (immunofluorescence). Pretreatment with BSCI i) prevented IL-1-induced PTB; (ii) significantly attenuated cytokine and chemokine signals in maternal plasma, myometrium, decidua, and placenta, and amniotic fluid; (iii) suppressed myometrial contraction-associated genes, including Nfkb1, Ptgs2, Akr1c18, and Gja1; (iv) prevented global IL-1-induced changes in myometrial gene expression and chromatin accessibility (v) reduced uterine macrophage (F4/80+) counts and prevented the increase in pro-inflammatory M1-like macrophages observed with IL-1-treatment. BSCI-treated dams that delivered at term had live pups with normal placental and fetal weight. Taken together, BSCI reduced the incidence of IL-1-mediated PTB and maintained uterine quiescence by suppressing uterine inflammation and genome-wide changes in labor gene expression and chromatin accessibility. BSCI represents a promising therapeutic approach for PTB prevention in high-risk pregnant women.

physiology↗

bioRxiv2025

Early Indirect Neurogenesis transitions to late Direct Neurogenesis in mouse cerebral cortex development

The cerebral cortex must contain the appropriate numbers of neurons in each layer to acquire its proper functional organization. Accordingly, neurogenesis requires precise regulation along development. Cortical neurons are made either directly by Radial Glia Cells (RGCs) that self- consume, or indirectly from RGCs via Intermediate Progenitor Cells (IPCs) and largely preserving the RGC pool. According to the standing model of cortical development, Direct Neurogenesis predominates at early stages of development, and progressively shifts to Indirect Neurogenesis, which predominates at late stages. However, neurogenesis at early stages should be compatible with RGC amplification, and neurogenesis at late stages needs to involve RGC consumption, which seems in conflict with the standing model. Here we studied the modes of neurogenesis along cortical development using multiple approaches, including birthdating, live imaging and MADM clone labeling. Contrary to the established dogma, our data show that Indirect Neurogenesis clearly predominates at early developmental stages, gradually shifting to Direct Neurogenesis at late stages. These findings challenge the current model of cortical neurogenesis, and prompt a re-evaluation of previous and ongoing work about the genetic and molecular mechanisms regulating this process.

neuroscience↗