RESUMEN
Pregnancy reprograms mammary epithelial cells (MECs) to control their responses to pregnancy hormone re-exposure and carcinoma progression. However, the influence of pregnancy on the mammary microenvironment is less clear. Here, we used single-cell RNA sequencing to profile the composition of epithelial and non-epithelial cells in mammary tissue from nulliparous and parous female mice. Our analysis indicates an expansion of γδ natural killer T-like immune cells (NKTs) following pregnancy and upregulation of immune signaling molecules in post-pregnancy MECs. We show that expansion of NKTs following pregnancy is due to elevated expression of the antigen-presenting molecule CD1d on MECs. Loss of CD1d expression on post-pregnancy MECs, or overall lack of activated NKTs, results in mammary oncogenesis. Collectively, our findings illustrate how pregnancy-induced changes modulate the communication between MECs and the immune microenvironment and establish a causal link between pregnancy, the immune microenvironment, and mammary oncogenesis.
Asunto(s)
Proliferación Celular , Transformación Celular Neoplásica/inmunología , Células Epiteliales/inmunología , Activación de Linfocitos , Glándulas Mamarias Animales/inmunología , Neoplasias Mamarias Experimentales/inmunología , Células T Asesinas Naturales/inmunología , Paridad , Animales , Antígenos CD1d/metabolismo , Comunicación Celular , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Células Epiteliales/metabolismo , Células Epiteliales/patología , Femenino , Regulación Neoplásica de la Expresión Génica , Genes BRCA1 , Genes myc , Glándulas Mamarias Animales/metabolismo , Glándulas Mamarias Animales/patología , Neoplasias Mamarias Experimentales/genética , Neoplasias Mamarias Experimentales/metabolismo , Neoplasias Mamarias Experimentales/patología , Ratones Endogámicos BALB C , Ratones Endogámicos NOD , Ratones SCID , Ratones Transgénicos , Células T Asesinas Naturales/metabolismo , Embarazo , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Transducción de Señal , Microambiente TumoralRESUMEN
The developing mammary gland depends on several transcription-dependent networks to define cellular identities and differentiation trajectories. Recent technological advancements that allow for single-cell profiling of gene expression have provided an initial picture into the epithelial cellular heterogeneity across the diverse stages of gland maturation. Still, a deeper dive into expanded molecular signatures would improve our understanding of the diversity of mammary epithelial and non-epithelial cellular populations across different tissue developmental stages, mouse strains and mammalian species. Here, we combined differential mammary gland fractionation approaches and transcriptional profiles obtained from FACS-isolated mammary cells to improve our definitions of mammary-resident, cellular identities at the single-cell level. Our approach yielded a series of expression signatures that illustrate the heterogeneity of mammary epithelial cells, specifically those of the luminal fate, and uncovered transcriptional changes to their lineage-defined, cellular states that are induced during gland development. Our analysis also provided molecular signatures that identified non-epithelial mammary cells, including adipocytes, fibroblasts and rare immune cells. Lastly, we extended our study to elucidate expression signatures of human, breast-resident cells, a strategy that allowed for the cross-species comparison of mammary epithelial identities. Collectively, our approach improved the existing signatures of normal mammary epithelial cells, as well as elucidated the diversity of non-epithelial cells in murine and human breast tissue. Our study provides a useful resource for future studies that use single-cell molecular profiling strategies to understand normal and malignant breast development.
Asunto(s)
Células Epiteliales/fisiología , Perfilación de la Expresión Génica/métodos , Glándulas Mamarias Animales/fisiología , Glándulas Mamarias Humanas/fisiología , Análisis de Secuencia de ARN/métodos , Análisis de la Célula Individual/métodos , Transcriptoma , Animales , Linaje de la Célula/fisiología , Células Epiteliales/citología , Femenino , Humanos , Glándulas Mamarias Animales/citología , Glándulas Mamarias Humanas/citología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BLRESUMEN
Pregnancy causes a series of cellular and molecular changes in mammary epithelial cells (MECs) of female adults. In addition, pregnancy can also modify the predisposition of rodent and human MECs to initiate oncogenesis. Here, we investigate how pregnancy reprograms enhancer chromatin in the mammary epithelium of mice and influences the transcriptional output of the oncogenic transcription factor cMYC. We find that pregnancy induces an expansion of the active cis-regulatory landscape of MECs, which influences the activation of pregnancy-related programs during re-exposure to pregnancy hormones in vivo and in vitro. Using inducible cMYC overexpression, we demonstrate that post-pregnancy MECs are resistant to the downstream molecular programs induced by cMYC, a response that blunts carcinoma initiation, but does not perturb the normal pregnancy-induced epigenomic landscape. cMYC overexpression drives post-pregnancy MECs into a senescence-like state, and perturbations of this state increase malignant phenotypic changes. Taken together, our findings provide further insight into the cell-autonomous signals in post-pregnancy MECs that underpin the regulation of gene expression, cellular activation, and resistance to malignant development.
Asunto(s)
Glándulas Mamarias Animales/metabolismo , Animales , Carcinogénesis/genética , Transformación Celular Neoplásica/patología , Epigénesis Genética , Epigenoma , Células Epiteliales/metabolismo , Femenino , Regulación de la Expresión Génica , Glándulas Mamarias Animales/citología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Oncogenes/genética , Embarazo , Complicaciones del Embarazo/etiología , Complicaciones del Embarazo/genética , Transducción de Señal , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Drug resistance to our current stock of antibiotics is projected to increase to levels that threaten our ability to reduce and eliminate bacterial infections, which is now considered one of the primary health care crises of the 21st century. Traditional antibiotic agents (e.g., penicillin) paved the way for massive advances in human health, but we need novel strategies to maintain the upper hand in the battle against pathogenic bacteria. Nontraditional strategies, such as targeted immunotherapies, could prove fruitful in complementing our antibiotic arsenal.