Cigarette smoke-induced cell cycle arrest in spermatocytes [GC-2spd(ts)] is mediated through crosstalk between...

Area of Science:

• Reproductive toxicology
• Molecular cell biology

Background:

• Cigarette smoke condensate (CSC) previously shown to induce growth arrest in mouse spermatocyte cell lines (GC-2spd(ts)) via the AHR-NRF2 pathway.
• MAPK signaling pathways (p38 and ERK) are implicated in cellular stress responses.

Purpose of the Study:

• To investigate the role of AHR and MAPK signaling in CSC-induced spermatocyte growth arrest.
• To elucidate the crosstalk between AHR, NRF2, and MAPK pathways in response to CSC exposure.

Main Methods:

• Utilized a mouse spermatocyte cell line (GC-2spd(ts)) exposed to CSC.
• Employed pharmacological inhibitors for AHR, p38 MAPK, and ERK (MEK1).
• Applied quantitative real-time PCR (QRT-PCR), western blot, immunofluorescence, RNA interference (siRNA), and cyclin analysis.

Main Results:

• CSC activates p38 and ERK MAPK signaling through AHR in GC-2spd(ts) cells.
• Inhibitors of AHR, p38, and ERK significantly reversed CSC-induced growth arrest.
• Demonstrated crosstalk and cross-regulatory loops between AHR, NRF2, Atf3, and E2f4 pathways.
• Confirmed CSC-induced growth inhibition and cell death through gene silencing and cyclin downregulation.

Conclusions:

• CSC-induced spermatocyte growth arrest and cell death involve the activation of AHR and MAPK signaling pathways.
• A complex crosstalk between AHR-NRF2 and MAPK pathways underlies the molecular mechanisms of cigarette smoke's reproductive toxicity.