Single-cell transcriptomics reveals stepwise transformation of epithelial cells into Non-Professional Phagocytes

Area of Science:

• Developmental Biology
• Cell Biology
• Molecular Biology

Background:

• Epithelial cell differentiation into Non-Professional Phagocytes (NPPs) is vital for tissue homeostasis and apoptotic debris clearance.
• The genetic control of this epithelial-to-NPP transition in the Drosophila ovary is not fully understood.

Purpose of the Study:

• To elucidate the genetic mechanisms governing epithelial cell differentiation into NPPs in Drosophila.
• To characterize the transcriptional dynamics and key regulatory pathways involved in NPP maturation.

Main Methods:

• Utilized a Drosophila model with Notch Intracellular Domain (NICD) overexpression to induce epithelial-to-NPP transition.
• Employed single-cell RNA sequencing and trajectory analysis to identify transcriptional phases.
• Performed SCENIC, ChiP-seq, and functional assays to identify and validate key regulators.

Main Results:

• Identified three distinct transcriptional phases of NPP maturation: metabolic activation, cytoskeletal remodeling, and autophagy.
• Discovered the JNK effector Jun-related antigen (Jra) and Arp2/Arp3 as critical regulators of cytoskeletal remodeling.
• Confirmed the JNK-Jra-Arp2/3 axis is essential for cytoplasmic expansion and debris clearance during NPP differentiation.

Conclusions:

• The study delineates the transcriptional landscape of NPP differentiation, revealing distinct maturation stages.
• The JNK-Jra-Arp2/3 signaling pathway plays a pivotal role in regulating cytoskeletal dynamics necessary for NPP function.
• This work provides significant insights into the molecular mechanisms underlying phagocytic cell differentiation and tissue repair.