The Affiliated Hospital of Guiyang Medical University, Guiyang, 550004, China.
Children's Hospital of Soochow University, Suzhou, 215025, China.
BMC Pediatr. 2024 Sep 28;24(1):608. doi: 10.1186/s12887-024-05047-9.
Colony stimulating factor 1 (CSF1) is generally expressed by immune cells in response to pro-inflammatory stimuli. The CSF1 receptor (CSFR) is activated by CSF1, and plays a key role in macrophage homeostasis. Furthermore, the CSF1R macrophages maintain homeostasis in the intestinal epithelium. The aim of this study was to explore the functions of CSF1-expressing and CSF1R macrophages in necrotizing enterocolitis (NEC), which commonly affects the ileum of neonates.
In-situ CSF1 expression in the intestines of neonates with NEC or intestinal atresia (n = 4 each) was detected by immunofluorescence staining. The CSF1 levels in the intestinal crypt-derived organoid cultures were measured by ELISA. Peripheral blood monocyte-derived Mφ macrophages were co-cultured with the organoids and stimulated with lipopolysaccharide (LPS) to mimic the inflamed state of the ileum in NEC patients.
CSF1 was expressed in the intestinal epithelial cells of the fetal and neonatal samples, but suppressed in the NEC samples. Furthermore, CSF1 expression was downregulated in the intestinal crypt-derived organoids by LPS. CSF1R macrophages were detected near the intestinal crypts in the non-inflamed intestines but were absent in tissues obtained from pediatric NEC patients. Peripheral blood monocyte-derived macrophages promoted intestinal organoid proliferation in vitro following CSF1 stimulation. Finally, low concentrations of LPS slightly enhanced the proliferation of organoids co-cultured with the macrophages, whereas higher doses had a significant inhibitory effect.
Intestinal epithelial cells express CSF1 to regulate the resident macrophages, maintain epithelial homeostasis, and resist infection. The abundant CSF1R macrophages in the fetal intestine may overexpress TNF-α upon activation of the TLR4/NF-κB pathway, resulting in epithelial damage and NEC induction.
集落刺激因子 1（CSF1）通常由免疫细胞在响应促炎刺激时表达。CSF1 受体（CSFR）被 CSF1 激活，在巨噬细胞稳态中发挥关键作用。此外，CSF1R 巨噬细胞维持肠道上皮细胞的稳态。本研究旨在探索 CSF1 表达的巨噬细胞和 CSF1R 巨噬细胞在常影响新生儿回肠的坏死性小肠结肠炎（NEC）中的功能。
通过免疫荧光染色检测 NEC 或肠闭锁新生儿肠道中 CSF1 的原位表达（每组各 4 例）。通过 ELISA 测量肠道隐窝衍生类器官培养物中的 CSF1 水平。将外周血单核细胞衍生的 Mφ 巨噬细胞与类器官共培养，并以脂多糖（LPS）刺激以模拟 NEC 患者回肠的炎症状态。
CSF1 在胎儿和新生儿样本的肠道上皮细胞中表达，但在 NEC 样本中受到抑制。此外，LPS 下调了肠道隐窝衍生类器官中的 CSF1 表达。在非炎症肠道中，CSF1R 巨噬细胞在肠道隐窝附近被检测到，但在儿科 NEC 患者的组织中不存在。外周血单核细胞衍生的巨噬细胞在 CSF1 刺激下促进肠道类器官的体外增殖。最后，低浓度 LPS 轻微增强了与巨噬细胞共培养的类器官的增殖，而高浓度则具有显著的抑制作用。
肠道上皮细胞表达 CSF1 以调节常驻巨噬细胞，维持上皮细胞稳态并抵抗感染。在胎儿肠道中丰富的 CSF1R 巨噬细胞可能在 TLR4/NF-κB 通路激活时过度表达 TNF-α，导致上皮损伤和 NEC 诱导。
