Journal: Frontiers in Cellular Neuroscience

Article Title: Etifoxine drives macrophage M2 polarization via Schwann cell-derived progesterone activation of PPARγ to accelerate peripheral nerve repair

doi: 10.3389/fncel.2026.1789450

Figure Lengend Snippet: ETX Promotes M2 polarization via progesterone-mediated activation. (A) Left panel: Progesterone (Pg) levels are increased in ETX-treated HSCs (48 h). Middle panel: TSPO knockdown blocks ETX-dependent Pg production in HSCs. Right panel: ETX treatment fails to upregulate Pg levels in THP-1 cells. Data are presented as means ± SEMs; n = 3; ** P < 0.01 compared with the Ctrl (left panel, unpaired t -test); ** P < 0.01 compared with ETX, ns, not significant (middle and right panels, one-way ANOVA, with Tukey’s post-hoc test). (B) Flow cytometry analysis of CD68 + CD206 + cells in cocultures. i. Ctrl (Etifoxine); ii. cocultures + ETX; iii. cocultures + ETX + RU486 (RU486; 2 μM). iv. ETX + Progesterone. Data are presented as means ± SEMs; n = 3; ** P < 0.01, **** P < 0.0001, ns, not significant (one-way ANOVA with Tukey’s post-hoc test). (C) Flow cytometry analysis of CD68 + CD206 + cells in co-cultures. i. Control; ii. Co-culture with ETX; iii. Co-culture with ETX + Gabazine; iv. Co-culture with ETX + RU486; v. Co-culture with ETX + RU486 + Gabazine. (D) Quantitative analysis of CD68 + CD206 + cells from the flow cytometry data shown in (C) . Data are presented as means ± SEMs; n = 3; **** P < 0.0001, ns, not significant (one-way ANOVA with Tukey’s post-hoc test). (E) RNA-seq analysis of DEGs (ETX coculture vs. ETX alone). Volcano plot: log 2 FC > 0.263 (1.2-fold change), p < 0.05. (F) KEGG enrichment analysis of upregulated DEGs. The top pathways are shown (bubble size: gene ratio; color: −log10( P ); threshold: log2FC > 0.585).

Article Snippet: Progesterone (Pg) levels were measured using competitive ELISA (Elabscience #E-OSEL-H0011).

Techniques: Activation Assay, Knockdown, Flow Cytometry, Control, Co-Culture Assay, RNA Sequencing

Journal: Frontiers in Cellular Neuroscience

Article Title: Etifoxine drives macrophage M2 polarization via Schwann cell-derived progesterone activation of PPARγ to accelerate peripheral nerve repair

doi: 10.3389/fncel.2026.1789450

Figure Lengend Snippet: Progesterone drives PPARγ-mediated fatty acid oxidation and mitophagy activation. (A) Expression of genes in the PPAR signaling pathway. The heatmap shows the RNA-seq data (rows: z scores; columns: samples). (B) GSEA of PPAR signaling. ETX coculture vs. ETX alone (NES = 1.69, FDR = 0.086). (C) GSEA of mitophagy. ETX coculture vs. ETX alone (NES = 1.53, FDR = 0.131). (D) Fatty acid oxidation (FAO) capacity in co-cultures. The levels of FAO were measured by ELISA in ETX-treated HSCs, co-cultures with ETX, and co-cultures with ETX plus GW9662. Data are presented as means ± SEMs; n = 3; ** P < 0.01 (one-way ANOVA followed by Tukey’s test). (E) GSEA of NRF2-ARE signaling (NES = 1.8, FDR = 0.05). (F) Western blots showing the levels of PPARγ, CPT1A, and PGC1α in cocultures ± ETX/RU486 (RU486, 2 μM). (G) Allopregnanolone levels in different groups. The concentrations of allopregnanolone were measured by ELISA in control, ETX-treated, and ETX with Dutasteride groups. Data are presented as means ± SEMs; n = 3; ** P < 0.01, *** P < 0.001 (one-way ANOVA followed by Tukey’s test). (H) Western blots showing the levels of PPARγ. (I) Densitometry of the blots in (F) . The data are presented as means ± SEMs; n = 3; * P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001 (Student’s t- test, one-way ANOVA followed by Tukey’s test). (J) Flow cytometry analysis of CD68 + CD206 + cells in cocultures. i. Ctrl (Etifoxine); ii. cocultures + ETX; iii. cocultures + ETX + GW9662 (GW9662; 10 μM). Data are presented as means ± SEMs; n = 3; *** P < 0.001, **** P < 0.0001 (one-way ANOVA followed by Tukey’s test).

Article Snippet: Progesterone (Pg) levels were measured using competitive ELISA (Elabscience #E-OSEL-H0011).

Techniques: Activation Assay, Expressing, RNA Sequencing, Enzyme-linked Immunosorbent Assay, Western Blot, Control, Flow Cytometry

Journal: Frontiers in Cellular Neuroscience

Article Title: Etifoxine drives macrophage M2 polarization via Schwann cell-derived progesterone activation of PPARγ to accelerate peripheral nerve repair

doi: 10.3389/fncel.2026.1789450

Figure Lengend Snippet: Progesterone drives mitophagy via PPARγ-dependent signaling. (A) Mitophagy-related gene expression. The heatmap shows the RNA-seq data (rows: z scores; columns: samples). (B) Top panel: Western blot analysis of autophagy flux. The levels of mitophagy markers in cocultures treated with ETX ± bafilomycin A1 (Baf A1, 50 nM; lysosomal inhibitor) are shown. Bottom panel: loading control (β-actin). (C–G) Quantification of the protein levels in (B) : BNIP3L, Parkin, NLRP3, LC3-II, and p62. Data are shown as means ± SEMs; n = 3; * P < 0.05 and ** P < 0.01 compared with ETX alone (Student’s t -test, one-way ANOVA with Tukey’s post-hoc test). (H) Mitophagy flux was measured using the mito-QC reporter. Representative confocal images show mCherry + GFP – puncta (red) that indicate mitochondria in lysosomes; the GFP signal (green) is quenched in acidic compartments. Scale bar: 20 μm. (I) Top panel: BNIP3L expression after PPARγ inhibition. WB of cocultures treated with ETX ± GW9662 (10 μM) is shown. Bottom panel: β-actin control. (J) Quantification of the BNIP3L levels in (I) . Data are presented as means ± SEMs; n = 3; *** P < 0.01 compared with ETX (one-way ANOVA with Tukey’s post-hoc test). (K) PPARγ-dependent mitophagy. Representative images show the levels of the mito-QC reporter in ETX ± GW9662-treated macrophages. Scale bar: 20 μm. (L) Statistical analysis was performed using one-way ANOVA to compare the number of mCherry-only puncta per cell among the three groups: ETX, coculture + ETX, and coculture + ETX + GW9662. *** P < 0.001 (one-way ANOVA with Tukey’s post-hoc test).

Article Snippet: Progesterone (Pg) levels were measured using competitive ELISA (Elabscience #E-OSEL-H0011).

Techniques: Gene Expression, RNA Sequencing, Western Blot, Control, Expressing, Inhibition