Tao Jing

Abstract Macrophages constitute one of the most common components of immune cells, which penetrate tumors and they have a key role in tumor prognosis. Here, we identified an unrecognized macrophage subpopulation, which favors tumorigenesis. These macrophages express programmed cell death protein 1 (PD1) in a constitutive manner and accumulates in esophageal squamous cell carcinoma (ESCC) in advanced stage of the disease and is negatively associated with the survival of ESCC patients. The PD1 + tumor-associated macrophages (PD1 + TAMs) displayed surface pattern and function akin to M2: a substantial enhancement in CD206 and IL-10 expression; a specific reduction in HLA-DR, CD64, and IL-12 expression; and a significant increase in the ability to inhibit CD8 + T-cell proliferation. Triggering of PD1 signal is effective in increasing PD1 + TAM function. Moreover, exosomal HMGB1 obtained from tumors are efficient in triggering differentiation of monocytes into PD1 + TAMs, which display phenotypic and functional properties of M2. Overall, our work is the first finding to confirm that exosomal HMGB1 obtained from ESCC can successfully trigger clonal expansion of PD1 + TAM. Further, as the macrophages exhibit an M2-like surface profile and function, thereby creating conditions for development of ESCC. Thus, effective methods of treatment include combining immunotherapy with targeting PD1 + TAMs and tumor-derived exosomal HMGB1 to resuscitate immune function in individuals suffering from ESCC.

Type 2 diabetes mellitus is one of the most prevalent metabolic diseases presenting with systemic pathologies, including reproductive disorders in male diabetic patients. However, the molecular mechanisms that contributing to spermatogenesis dysfunction in diabetic patients have not yet been fully elucidated. Here, we perform STRT-seq to examine the transcriptome of diabetic patients' testes at single-cell resolution including all major cell types of the testis. Intriguingly, whereas spermatogenesis appears largely preserved, the gene expression profiles of Sertoli cells and the blood-testis barrier (BTB) structure are dramatically impaired. Among these deregulate pathways, the Apelin (APLN) peptide/Apelin-receptor (APJ) axis is hyper-activated in diabetic patients' testes. Mechanistically, APLN is produced locally by Sertoli cells upon high glucose treatment, which subsequently suppress the production of carnitine and repress the expression of cell adhesion genes in Sertoli cells. Together, these effects culminate in BTB structural dysfunction. Finally, using the small molecule APLN receptor antagonist, ML221, we show that blocking APLN/APJ significantly ameliorate the BTB damage and, importantly, improve functional spermatogenesis in diabetic db/db mice. We also translate and validate these findings in cultured human testes. Our findings identify the APLN/APJ axis as a promising therapeutic target to improve reproduction capacity in male diabetic patients.