Maternal B cell signaling orchestrates fetal development in mice

Area of Science:

• Reproductive immunology
• Developmental biology
• Maternal-fetal medicine

Background:

• The role of B cells in early embryonic and fetal development is largely unexplored.
• Understanding maternal B cell signaling is crucial for identifying factors influencing placental and fetal growth.

Purpose of the Study:

• To investigate the impact of maternal B cell deficiency or impaired signaling on placental and fetal development.
• To elucidate the molecular pathways involving B cells in pregnancy maintenance and preterm birth.

Main Methods:

• Utilized genetically modified mouse models including CD19-deficient, B cell-specific MyD88-deficient, and B cell-specific IL10-deficient females.
• Employed ultrasound and Doppler measurements to assess pregnancy progression, placental parameters, and uterine artery resistance.
• Administered lipopolysaccharide challenge to evaluate susceptibility to preterm birth.

Main Results:

• Reduced implantation numbers and decreased implantation areas were observed in B cell-specific MyD88-deficient and MyD88-deficient mice.
• B cell-specific MyD88 or IL10 deficiency led to reduced placental thickness, diameter, and area.
• B cell-specific MyD88 and IL10 deficiency, as well as CD19 deficiency, increased susceptibility to lipopolysaccharide-induced preterm birth.

Conclusions:

• B cell-specific MyD88 and IL10 expression are essential for successful in utero development.
• Interleukin-10 (IL10)-expressing B cells play a role in regulating uterine blood flow during pregnancy.
• Maternal B cell expression of CD19, MyD88, and IL10 influences the risk of preterm birth.