Pancreatic cancer is marked by complement-high blood monocytes and tumor-associated macrophages

Pancreatic ductal adenocarcinoma (PDA) is accompanied by reprogramming of the local microenvironment, but changes at distal sites are poorly understood. We implanted biomaterial scaffolds, which act as an artificial premetastatic niche, into immunocompetent tumor-bearing and control mice, and identified a unique tumor-specific gene expression signature that includes high expression of C1qa, C1qb, Trem2, and Chil3 Single-cell RNA sequencing mapped these genes to two distinct macrophage populations in the scaffolds, one marked by elevated C1qa, C1qb, and Trem2, the other with high Chil3, Ly6c2 and Plac8 In mice, expression of these genes in the corresponding populations was elevated in tumor-associated macrophages compared with macrophages in the normal pancreas. We then analyzed single-cell RNA sequencing from patient samples, and determined expression of C1QA, C1QB, and TREM2 is elevated in human macrophages in primary tumors and liver metastases. Single-cell sequencing analysis of patient blood revealed a substantial enrichment of the same gene signature in monocytes. Taken together, our study identifies two distinct tumor-associated macrophage and monocyte populations that reflects systemic immune changes in pancreatic ductal adenocarcinoma patients.

Liquid-liquid phase separation facilitates the biogenesis of secretory storage granules

Insulin is synthesized by pancreatic β-cells and stored into secretory granules (SGs). SGs fuse with the plasma membrane in response to a stimulus and deliver insulin to the bloodstream. The mechanism of how proinsulin and its processing enzymes are sorted and targeted from the trans-Golgi network (TGN) to SGs remains mysterious. No cargo receptor for proinsulin has been identified. Here, we show that chromogranin (CG) proteins undergo liquid-liquid phase separation (LLPS) at a mildly acidic pH in the lumen of the TGN, and recruit clients like proinsulin to the condensates. Client selectivity is sequence-independent but based on the concentration of the client molecules in the TGN. We propose that the TGN provides the milieu for converting CGs into a "cargo sponge" leading to partitioning of client molecules, thus facilitating receptor-independent client sorting. These findings provide a new receptor-independent sorting model in β-cells and many other cell types and therefore represent an innovation in the field of membrane trafficking.

Association between neighborhood stressors and allostatic load in breast cancer survivors: the Pathways Study

Allostatic load (AL) is an intermediary outcome through which neighborhood drivers of health may impact cancer survivorship outcomes. We examined associations of neighborhood stressors and AL in 2553 women with breast cancer recruited into the Pathways Study in 2006-2013. AL score was derived from biomarkers in the cardiovascular, metabolic, and immune domains of physiologic stress measured within 3 years after baseline. Neighborhood data were appended to participants' geocoded baseline addresses. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate associations between neighborhood stressors and risk of higher AL score. Adjusting for age and stage, high AL was positively associated with low versus high neighborhood socioeconomic status (nSES; OR = 2.24; 95% CI, 1.61-3.12) and green space (OR = 1.55; 95% CI, 1.18-2.03), high versus low traffic (OR = 1.32; 95% CI, 1.01-1.72), crime (OR = 1.32; 95% CI, 1.05-1.67), household crowding (OR = 1.57; 95% CI, 1.22-2.01), and more versus no fast-food restaurants (OR = 1.50; 95% CI, 1.21-1.84). Associations remained for nSES and fast-food restaurants after coadjustment with other neighborhood stressors and for fast-food restaurants after additional adjustment with individual sociodemographic and lifestyle factors. Our preliminary findings can inform future studies of the physiologic effects of neighborhood stressors, which collectively may help improve survivorship outcomes for the growing population of breast cancer survivors.

Aging human abdominal subcutaneous white adipose tissue at single cell resolution

White adipose tissue (WAT) is a robust energy storage and endocrine organ critical for maintaining metabolic health as we age. Our aim was to identify cell-specific transcriptional aberrations that occur in WAT with aging. We leveraged full-length snRNA-Seq and histology to characterize the cellular landscape of human abdominal subcutaneous WAT in a prospective cohort of 10 younger (≤30 years) and 10 older individuals (≥65 years) balanced for sex and body mass index (BMI). The older group had greater cholesterol, very-low-density lipoprotein, triglycerides, thyroid stimulating hormone, and aspartate transaminase compared to the younger group (p < 0.05). We highlight that aging WAT is associated with adipocyte hypertrophy, increased proportions of lipid-associated macrophages and mast cells, an upregulation of immune responses linked to fibrosis in pre-adipocyte, adipocyte, and vascular populations, and highlight CXCL14 as a biomarker of these processes. We show that older WAT has elevated levels of senescence marker p16 in adipocytes and identify the adipocyte subpopulation driving this senescence profile. We confirm that these transcriptional and phenotypical changes occur without overt fibrosis and in older individuals that have comparable WAT insulin sensitivity to the younger individuals.