Early modulation of autophagy-associated markers in murine adenomyosis and selective persistence in human stromal lesions

Background
Adenomyosis is a heterogeneous uterine disorder characterized by the presence of endometrial tissue within the myometrium. Autophagy, a key homeostatic process involved in tissue remodeling and stress adaptation, has been inconsistently described in adenomyosis. This study aimed to define the temporal and compartment-specific regulation of autophagy-associated markers during disease progression, using a tamoxifen-induced CD1 mouse model and human uterine samples.

Methods
Female neonatal CD1 mice were exposed to oral tamoxifen from postnatal days 1–4 and evaluated at 1 and 3 months. Uterine tissues were examined for autophagy- and apoptosis-related transcripts (RT-qPCR), autophagy-associated protein expression (Western blot) and LC3B distribution (immunohistochemistry and immunofluorescence). LC3B expression was also assessed in paraffin-embedded human uterine samples from women with histologically confirmed adenomyosis and from controls without uterine pathology.

Results

At one month, a restricted set of autophagy/apoptosis-related transcripts (
Akt1, Mapk1, Nfkb1, Cxcr4, Bax, Bcl2, Bcl2l1 and Ulk2
) was modulated, and LC3B protein levels were decreased, coinciding with early myometrial disorganization and stromal invasion. By three months, gene and LC3B staining differences were no longer detectable by the assays used, despite established lesions, suggesting biological adaptation or involvement of compensatory pathways. In human adenomyosis tissues, LC3B reduction was confined to the stromal compartment of ectopic lesions, whereas glandular and eutopic endometrium remained comparable to controls, indicating a persistent stromal-specific alteration of autophagy-associated markers.

Conclusions
Modulation of autophagy-associated markers is an early and transient event in murine adenomyosis initiation, whereas in human disease, stromal-specific LC3B reduction persists in established lesions. These findings indicate that autophagy-associated regulation is temporally and spatially distinct in adenomyosis and suggest that stromal autophagy-associated dysregulation may represent a pathway for future therapeutic exploration, while further studies are required to determine its functional and causal relevance.