Devos, M. | Search bioRxiv

bioRxiv2024

Transcriptomic signatures of mouse ovarian aging and estropausal transition at single cell resolution

Female reproductive aging affects fertility and overall health. Functional decline in mouse ovary during reproductive aging is accompanied by estrous cycle prolongation and cessation. However, the molecular mechanism underlying reproductive aging concomitant with such cycle changes remains unclear. Using single-cell transcriptomics, we characterized aging signatures in mouse ovaries across the reproductive lifespan ranging from reproductively young (regular cycle) through peri-estropause (regular vs. irregular cycles) to post-estropause age (acyclic). Reproductive aging significantly remodeled cell compositions and increased transcriptional heterogeneity, with more pronounced changes post-estropause, exhibiting coordinated alterations across cell types in the ovary. Genes undergoing monotonic changes during reproductive aging across cell types were consistently enriched in the conserved pathways of aging, including oxidative phosphorylation, stress responses, and proteostasis. Additionally, cell type-specific changes were identified including dysregulation of hormone synthesis in granulosa cells, alterations in collagen and hyaluronan metabolism in stromal and early theca cells, and functional decline of a unique phagocytosis-associated macrophage. Aging also led to a significant decrease in cell-cell communications, particularly between stromal and granulosa cells, and an increase in extracellular vesicle secretion. Furthermore, we found increased expression of the senescence marker Cdkn1a and senescence-associated secretory phenotype (SASP) factors during ovarian aging, especially in granulosa cells. Notably, most of these aging-associated changes were more pronounced in irregular cycling ovaries compared to the regular cycling counterparts at the same age during the peri-estropause stage, suggesting that aging-related molecular changes in the ovary drive the estropausal transition in mice.

bioinformatics↗

bioRxiv2020

Sensing of endogenous nucleic acids by ZBP1 induces keratinocyte necroptosis and skin inflammation

Aberrant detection of endogenous nucleic acids by the immune system can cause inflammatory disease. The scaffold function of the signalling kinase RIPK1 limits spontaneous activation of the nucleic acid sensor ZBP1. Consequently, loss of RIPK1 in keratinocytes induces ZBP1-dependent necroptosis and skin inflammation. Whether nucleic acid sensing is required to activate ZBP1 in RIPK1 deficient conditions and which immune pathways are associated with skin disease remained open questions. Using knock-in mice with disrupted ZBP1 nucleic acid binding activity, we report that sensing of endogenous nucleic acids by ZBP1 is critical in driving skin pathology characterised by antiviral and IL-17 immune responses. Inducing ZBP1 expression by interferons triggers necroptosis in RIPK1-deficient keratinocytes and epidermis-specific deletion of MLKL prevents disease, demonstrating that cell-intrinsic events cause inflammation. These findings indicate that dysregulated sensing of endogenous nucleic acid by ZBP1 can drive inflammation and may contribute to the pathogenesis of IL-17-driven inflammatory skin conditions such as psoriasis. SummaryDevos, Tanghe et al. find that the recognition of endogenous nucleic acids by the nucleic acid sensor ZBP1 causes necroptosis of RIPK1-deficient keratinocytes. This process drives the development of an inflammatory skin disease characterised by an IL-17 immune response.

immunology↗