Aging modifies endometrial dendritic cell function and unconventional double negative T cells in the human genital mucosa

Siddharth Parthasarathy; Zheng Shen; Francisco J Carrillo-Salinas; Vidya Iyer; Alison Vogell; Diego Illanes; Charles R Wira; Marta Rodriguez-Garcia

doi:10.1186/s12979-023-00360-w

Aging modifies endometrial dendritic cell function and unconventional double negative T cells in the human genital mucosa

Immun Ageing. 2023 Jul 14;20(1):34. doi: 10.1186/s12979-023-00360-w.

Authors

Siddharth Parthasarathy¹, Zheng Shen², Francisco J Carrillo-Salinas¹, Vidya Iyer³, Alison Vogell³, Diego Illanes³, Charles R Wira², Marta Rodriguez-Garcia⁴

Affiliations

¹ Department of Immunology, Tufts University School of Medicine, Boston, MA, USA.
² Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA.
³ Department of Gynecology and Obstetrics, Tufts Medical Center, Boston, MA, USA.
⁴ Department of Immunology, Tufts University School of Medicine, Boston, MA, USA. marta.rodriguez_garcia@tufts.edu.

Abstract

Background: Immune function in the genital mucosa balances reproduction with protection against pathogens. As women age, genital infections, and gynecological cancer risk increase, however, the mechanisms that regulate cell-mediated immune protection in the female genital tract and how they change with aging remain poorly understood. Unconventional double negative (DN) T cells (TCRαβ + CD4-CD8-) are thought to play important roles in reproduction in mice but have yet to be characterized in the human female genital tract. Using genital tissues from women (27-77 years old), here we investigated the impact of aging on the induction, distribution, and function of DN T cells throughout the female genital tract.

Results: We discovered a novel site-specific regulation of dendritic cells (DCs) and unconventional DN T cells in the genital tract that changes with age. Human genital DCs, particularly CD1a + DCs, induced proliferation of DN T cells in a TFGβ dependent manner. Importantly, induction of DN T cell proliferation, as well as specific changes in cytokine production, was enhanced in DCs from older women, indicating subset-specific regulation of DC function with increasing age. In human genital tissues, DN T cells represented a discrete T cell subset with distinct phenotypical and transcriptional profiles compared to CD4 + and CD8 + T cells. Single-cell RNA and oligo-tag antibody sequencing studies revealed that DN T cells represented a heterogeneous population with unique homeostatic, regulatory, cytotoxic, and antiviral functions. DN T cells showed relative to CD4 + and CD8 + T cells, enhanced expression of inhibitory checkpoint molecules and genes related to immune regulatory as well as innate-like anti-viral pathways. Flow cytometry analysis demonstrated that DN T cells express tissue residency markers and intracellular content of cytotoxic molecules. Interestingly, we demonstrate age-dependent and site-dependent redistribution and functional changes of genital DN T cells, with increased cytotoxic potential of endometrial DN T cells, but decreased cytotoxicity in the ectocervix as women age, with implications for reproductive failure and enhanced susceptibility to infections respectively.

Conclusions: Our deep characterization of DN T cell induction and function in the female genital tract provides novel mechanistic avenues to improve reproductive outcomes, protection against infections and gynecological cancers as women age.

Keywords: Dendritic cells; Double negative T cells; Endometrium; Menopause; Resident memory T cells; Sexually transmitted infections; Single-cell sequencing; TGF-β.