Science and Technology Production
Libro de resúmenes del X INTERNATIONAL SYMPOSIUM ON ANIMAL BIOLOGY OF REPRODUCTION. - ROLE OF AUTOPHAGY IN THE OVARY OF Lagostomus maximus THROUGHOUT PREGNANCY: A RODENT EXHIBITING CONTINOUS FOLLICULOGENESIS AND SUPPRESSED APOPTOSIS.
Congreso
Date:
2024Publishing House and Editing Place:
Colegio Brasilero de Reproducción AnimalSummary *
Germ cell loss, commonly associated with follicular atresia, has historically been linked to apoptosis, though alternative cell death mechanisms, such as autophagy, play a role. Lagostomus maximus (L.m), commonly called plains viscacha, exhibits reduced or suppressed apoptosis-Mediated follicular atresia in both fetal and adult ovaries, maintaining nearly a constant germ cell count from birth to puberty. Our recent findings indicate that autophagy eliminates altered follicles and residual corpora lutea in non-pregnant adult females, creating the space needed to continuously influx primordial follicles into the growing follicular pool, sustaining polyovulation. Aimed to increase our understanding of the possible cooperating role of autophagy and apoptosis in follicular atresia and/or follicular survival we analyzed both programmed cell death mechanisms in a rodent model, the South American plains vizcacha, Lagostomus maximus, whose females show highly suppressed apoptosis-dependent follicular atresia in the adult ovary, with continuous folliculogenesis and a process of pseudo-ovulation during pregnancy. Ovaries from pregnant individuals were collected at early (n=8), mid-term (n=8), and term (n=8) stages of pregnancy. Immunohistochemistry, employing markers such as BECLIN1, LC3BI-II, SQSTM1, LAMP1, and ACTIVE CASPASE-3 (AC3), assessed expression via relative optical density (ROD) and immunoreactive area (IRA). Protein colocalization analysis (LC3B-SQSTM1, LC3B-LAMP1, LC3B-AC3, and BECLIN1-BCL2) was conducted using confocal microscopy, while autophagic vacuole ultrastructure was examined via transmission electron microscopy (TEM). Results, presented as mean ± standard deviation (SD), underwent analysis of variance (ANOVA) with Bonferroni post-tests for multiple comparisons, where p<0.05 indicates significance. We report here our analysis of autophagy (BECLIN1, LAMP1, SQSTM1, and LC3B-I/II) and apoptosis markers (BCL2 and ACTIVE CASPASE-3) which revealed interactive behaviors between both processes, where autophagy could promote survival or cell death depending on the ovarian structure. Strong BECLIN1, LC3B-II, SQSTM1, and LAMP1 staining was observed in atretic follicles that also expressed nuclear cleaved-CASPASE-3. Normal follicles showed a slight expression of autophagy proteins but a strong expression of BCL2 and negative expression of ACTIVE CASPASE-3. Transmission electron microscopy revealed a high formation of autophagosomes, autolysosomes, and lysosomes in atretic follicles and a low number of autophagic vesicles in normal follicles. The co-expression of LC3B-SQSTM1, LC3B-LAMP1, and LC3B-AC3 was only detected in atretic follicles, while the co-expression of BECLIN1-BCL2 was only observed in normal follicles. These findings propose a dualrole for autophagy in L.m ovaries, actin firstly as a mechanism of cell death synergistically with apoptosis, primarily induced in atretic follicles providing the necessary space for maturation of primordial follicles that continuously enter the growing follicular pool to sustain pseudo-ovulation at mid pregnancy. Secondly, as a main contributor to tissue homeostasis, breaking down and recycling macromolecules that provide essential resources for developing follicles until the completion of pregnancy. Information provided by the agent in SIGEVAKey Words
LC3BVIZCACHABECLINLAMP1PREGNANCYAUTOPHAGYSQSTM1