Fig. 5: Lactate signal activates PPARγ to potentiate FSH action.

A–B AARS2 induces PPARγ in mouse GCs. The levels of PPARγ were compared between C57 and AARS2 GOE (A) and between C57 and Aars2 GKO (B) mouse GCs. C PPARγ was detected in COV434 cells, AARS2^−/− COV434 cells and in AARS2^−/− COV434 cells expressing either AARS2 or AARS2 mutations. D AARS2 CPT2-dependently induces PPARγ. The abilities of AARS2 and R199C to induce PPARγ were detected in AARS2^−/− COV434 cells and AARS2^−/− COV434 cells with silenced CPT2 through shRNAs. E Lactate induces PPARγ in cells. The PPARγ levels were detected in COV434 cells and AARS2^−/− COV434 cells with or without methyl L-lactate treatments. F Lactate induces PPARγ in mouse ovaries. The PPARγ levels were stained in ovarian sections of C57 and Aars2 GKO mice that were intraperitoneally injected with either PBS or 20 mg/kg lactate (scale bars, 200 μm (left panel), 50 μm (right panel)). G CPT2 lactylation accounts for lactate’s effects on inducing PPARγ. The PPARγ levels were detected in COV434 cells and CPT2 KD COV434 cells that were transfected with CPT2 and lactylation null CPT2^K457/8R. H THI increases and GW9662 decreases PPARγ signaling in mouse ovaries. Mean fluorescence intensity (MFI) of PPARγ signaling in ovarian sections of mice intraperitoneal injected with 30% DMSO, THI, or GW9662 (n = 6) was analyzed and represented as mean ± SEM. See also Fig. S6. I, J PPARγ inhibition diminished, and PPARγ activated FSH to promote mouse follicle development. Ovarian secondary follicles were counted in WT mice intraperitoneal injected with indicated FSH together with either 30% DMSO or GW9662 dissolved in 30% DMSO (I), and with either 30% DMSO or THI dissolved in 30% DMSO (J). Data are represented as mean ± SEM, n = 6. See also Fig. S6. K AARS2 overexpression promotes mouse follicle development. Ovarian secondary follicles were counted in WT and AARS2 GOE mice that were intraperitoneal injected with indicated FSH together with either 30% DMSO and GW9662 dissolved in 30% DMSO. Data are represented as mean ± SEM, n = 6. See also Fig. S6. L AARS2 promotes follicle growth in vitro. The maximum cross-sectional area of in vitro cultured WT and AARS2 GOE mouse follicles, with presence of gradient FSH, and under absence or presence of GW9662 was quantified. Data are represented as mean ± SEM, n = 6. See also Fig. S6. M Lactate promotes follicle development in mouse ovaries in an AARS2-dependent manner. Ovarian secondary follicles of WT and Aars2 GKO mice with or without intraperitoneal lactate injection were counted. Data are represented as mean ± SEM, n = 6. See also Fig. S6. N Lactate potentiates FSH to initiate follicle development in an AARS2-dependent manner. Ovarian secondary follicles of WT and Aars2 GKO mice that were with or without FSH, or lactate together with FSH, were quantified, n = 6. See also Fig. S6. O Lactate AARS2-dependently promotes follicles growth in vitro. The maximum cross-sectional area of WT and AARS2 GOE mice follicles cultured under with or without lactate in the culture media was quantified, n = 6. See also Fig. S6. P Lactate CPT2-dependently increases EdU incorporation. EdU positive cells in WT and CPT2 KD COV434 cells with or without lactate treatment were analyzed, n = 6. See also Fig. S6.