Highlights d TAM-expressed TREM2 is associated with T cell exhaustion and anti-PD-1 resistance d Effector-enhanced anti-TREM2 antibody treatment drives anti-tumor immunity d TAM abundance and suppression are reduced following anti-TREM2 therapy d Anti-TREM2 therapy potentiates T cell activation and response to anti-PD-1 treatment

There has been significant concern regarding fertility and reproductive outcomes during the SARS-CoV2 pandemic. Recent data suggests a high concentration of SARS-Cov2 receptors, ACE2 or TMPRSS2, in nasal epithelium and cornea, which explains person-to-person transmission. We investigated the prevalence of SARS-CoV2 receptors among reproductive tissues by exploring the single-cell sequencing datasets from uterus, myometrium, ovary, fallopian tube, and breast epithelium. We did not detect significant expression of either ACE2 or TMPRSS2 in the normal human myometrium, uterus, ovaries, fallopian tube, or breast. Furthermore, none of the cell types in the female reproductive organs we investigated, showed the co-expression of ACE2 with proteases, TMPRSS2, Cathepsin B (CTSB), and Cathepsin L (CTSL) known to facilitate the entry of SARS2-CoV2 into the host cell. These results suggest that myometrium, uterus, ovaries, fallopian tube, and breast are unlikely to be susceptible to infection by SARS-CoV2.

STUDY QUESTION What are the cellular composition and single-cell transcriptomic differences between myometrium and leiomyomas as defined by single-cell RNA sequencing? SUMMARY ANSWER We discovered cellular heterogeneity in smooth muscle cells (SMCs), fibroblast and endothelial cell populations in both myometrium and leiomyoma tissues. WHAT IS KNOWN ALREADY Previous studies have shown the presence of SMCs, fibroblasts, endothelial cells and immune cells in myometrium and leiomyomas. However, there is no information on the cellular heterogeneity in these tissues and the transcriptomic differences at the single-cell level between these tissues. STUDY DESIGN, SIZE, DURATION We collected five leiomyoma and five myometrium samples from a total of eight patients undergoing hysterectomy. We then performed single-cell RNA sequencing to generate a cell atlas for both tissues. We utilized our single-cell sequencing data to define cell types, compare cell types by tissue type (leiomyoma versus myometrium) and determine the transcriptional changes at a single-cell resolution between leiomyomas and myometrium. Additionally, we performed MED12-variant analysis at the single-cell level to determine the genotype heterogeneity within leiomyomas. PARTICIPANTS/MATERIALS, SETTING, METHODS We collected five MED12-variant positive leiomyomas and five myometrium samples from a total of eight patients. We then performed single-cell RNA sequencing on freshly isolated single-cell preparations. Histopathological assessment confirmed the identity of the samples. Sanger sequencing was performed to confirm the presence of the MED12 variant in leiomyomas. MAIN RESULTS AND ROLE OF CHANCE Our data revealed previously unknown heterogeneity in the SMC, fibroblast cell and endothelial cell populations of myometrium and leiomyomas. We discovered the presence of two different lymphatic endothelial cell populations specific to uterine leiomyomas. We showed that both myometrium and MED12-variant leiomyomas are relatively similar in cellular composition but differ in cellular transcriptomic profiles. We found that fibroblasts influence the leiomyoma microenvironment through their interactions with endothelial cells, immune cells and SMCs. Variant analysis at the single-cell level revealed the presence of both MED12 variants as well as the wild-type MED12 allele in SMCs of leiomyomatous tissue. These results indicate genotype heterogeneity of cellular composition within leiomyomas. LARGE SCALE DATA The datasets are available in the NCBI Gene Expression Omnibus (GEO) using GSE162122. LIMITATIONS, REASONS FOR CAUTION Our study focused on MED12-variant positive leiomyomas for single-cell RNA sequencing analyses. Leiomyomas carrying other genetic rearrangements may differ in their cellular composition and transcriptomic profiles. WIDER IMPLICATIONS FOR THE FINDINGS Our study provides a cellular atlas for myometrium and MED12-variant positive leiomyomas as defined by single-cell RNA sequencing. Our analysis provides significant insight into the differences between myometrium and leiomyomas at the single-cell level and reveals hitherto unknown genetic heterogeneity in multiple cell types within human leiomyomas. Our results will be important for future studies into the origin and growth of human leiomyomas. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by funding from the National Institute of Child Health and Human Development (HD098580 and HD088629). The authors declare no competing interests.

Highlights d TBI elevates distinct phenotypes of microglia, macrophages, and dendritic cells d Ccr2 deficiency alters cell proportions and reduces ISG expression in microglia d TBI induces crosstalk between microglia and circulating monocytes d Preclinical translational studies to target human CCR2 after TBI improves outcomes

49There has been significant concern regarding fertility and reproductive outcomes during the 50 SARS-CoV2 pandemic. Recent data suggests a high concentration of SARS-Cov2 receptors, 51 ACE2 or TMPRSS2, in nasal epithelium and cornea, which explains person-to-person 52 transmission. We investigated the prevalence of SARS-CoV2 receptors among reproductive 53 tissues by exploring the single-cell sequencing datasets from uterus, myometrium, ovary, 54 fallopian tube, and breast epithelium. We did not detect significant expression of either ACE2 55 or TMPRSS2 in the normal human myometrium, uterus, ovaries, fallopian tube, or breast. 56Furthermore, none of the cell types in the female reproductive organs we investigated, showed 57 the co-expression of ACE2 with proteases, TMPRSS2, Cathepsin B (CTSB), and Cathepsin 58 L (CTSL) known to facilitate the entry of SARS2-CoV2 into the host cell. These results suggest 59 that myometrium, uterus, ovaries, fallopian tube, and breast are unlikely to be susceptible to 60 infection by SARS-CoV2. Our findings suggest that COVID-19 is unlikely to contribute to 61 pregnancy-related adverse outcomes such as preterm birth, transmission of COVID-19 62 through breast milk, oogenesis and female fertility. 63 64 65 The coronavirus disease 2019, also commonly known as COVID-19 is caused by severe acute 66 respiratory syndrome coronavirus 2 (SARS-CoV2). SARS-CoV2 is a single-stranded positive 67 sense RNA virus first detected in Wuhan, China in late 2019 (1, 2). Since then, it has spread 68 worldwide, becoming a global pandemic, infecting nearly 3.58 million people worldwide and 69 resulting in 247,503 deaths (3). The severity of SARS-CoV2 varies as infected individuals can 70 be either asymptomatic or present mild to severe symptoms. Some of the most common 71 symptoms presented among the individuals infected with SARS-CoV2 include fever, cough, 72 pneumonia, occasional diarrhea, muscle pain, and new loss of sense of smell or taste (4). 73SARS-CoV2 binds to angiotensin-converting enzyme 2 (ACE2) receptor on the host cells 74 through spike (S) protein on the surface of the virus (2, 5). In addition to ACE2, entry of the virus into the host cell is also mediated by proteases TMPRSS2 (5). In the absence of 76 TMPRSS2, SARS-CoV2 is known to use cathepsins, CTSB and CTSL as an alternate to enter 77 the host cells (5). These proteases are required for the priming of the S protein after it binds 78 to the ACE2 receptor for its entry into the host cell (5, 6). 79Recent analyses of existing single-cell sequencing datasets showed that the SARS-CoV2 80 receptor, ACE2 is expressed in various cell types of organs of the respiratory tract, with 81 relatively high expression in goblet cells and ciliated cells of nasal epithelium and club cells in 82 the lung (7). In addition to respiratory tract, additional single cell sequencing analyses of 83 cornea, ileum, colon, heart, and gallbladder besides the respiratory tract identified cells that 84 are susceptible to SARS-CoV2 infection (7). These findings may ...