The zebrafish is an important animal model for stem cell biology, cancer, and immunology research. Histocompatibility represents a key intersection of these disciplines, however histocompatibility in zebrafish remains poorly understood. We examined a set of diverse zebrafish Class I major histocompatibility complex (MHC) genes that segregate with specific haplotypes at chromosome 19, and for which donor-recipient matching has been shown to improve engraftment after hematopoietic transplantation. Using flanking gene polymorphisms we identified six distinct chromosome 19 haplotypes. We describe several novel Class I U lineage genes and characterize their sequence properties, expression, and haplotype distribution. Altogether ten full-length zebrafish Class I genes were analyzed, mhc1uba through mhc1uka. Expression data and sequence properties indicate that most are candidate classical genes. Several substitutions in putative peptide anchor residues, often shared with deduced MHC molecules from additional teleost species, suggest flexibility in antigen binding. All ten zebrafish Class I genes were uniquely assigned among the six haplotypes, with dominant or co-dominant expression of one to three genes per haplotype. Interestingly, while the divergent MHC haplotypes display variable gene copy number and content, the different genes appear to have ancient origin, with extremely high levels of sequence diversity. Furthermore, haplotype variability extends beyond the MHC genes to include divergent forms of psmb8. The many disparate haplotypes at this locus therefore represent a remarkable form of genomic region configuration polymorphism. Defining the functional MHC genes within these divergent Class I haplotypes in zebrafish will provide an important foundation for future studies in immunology and transplantation.

Solid tumours are innervated by nerve fibres that arise from the autonomic and sensory peripheral nervous systems1–5. Whether the neo-innervation of tumours by pain-initiating sensory neurons affects cancer immunosurveillance remains unclear. Here we show that melanoma cells interact with nociceptor neurons, leading to increases in their neurite outgrowth, responsiveness to noxious ligands and neuropeptide release. Calcitonin gene-related peptide (CGRP)—one such nociceptor-produced neuropeptide—directly increases the exhaustion of cytotoxic CD8+ T cells, which limits their capacity to eliminate melanoma. Genetic ablation of the TRPV1 lineage, local pharmacological silencing of nociceptors and antagonism of the CGRP receptor RAMP1 all reduced the exhaustion of tumour-infiltrating leukocytes and decreased the growth of tumours, nearly tripling the survival rate of mice that were inoculated with B16F10 melanoma cells. Conversely, CD8+ T cell exhaustion was rescued in sensory-neuron-depleted mice that were treated with local recombinant CGRP. As compared with wild-type CD8+ T cells, Ramp1−/− CD8+ T cells were protected against exhaustion when co-transplanted into tumour-bearing Rag1-deficient mice. Single-cell RNA sequencing of biopsies from patients with melanoma revealed that intratumoral RAMP1-expressing CD8+ T cells were more exhausted than their RAMP1-negative counterparts, whereas overexpression of RAMP1 correlated with a poorer clinical prognosis. Overall, our results suggest that reducing the release of CGRP from tumour-innervating nociceptors could be a strategy to improve anti-tumour immunity by eliminating the immunomodulatory effects of CGRP on cytotoxic CD8+ T cells.

Mononuclear phagocytes exhibit complex interactions with cancer cells and might contribute to fibrin formation associated with malignancy through the production of procoagulant activity (PCA). We have studied the PCA of peritoneal macrophages in 8 patients with advanced (stages III or IV) ovarian cancer and of macrophages from regional lymph nodes in 14 patients with limited (stages I or II) uterine cancer; peritoneal and lymph-node macrophages from patients with benign gynecological tumors were used as reference cell populations. In all patients, PCA of blood monocytes was also studied. Peritoneal and lymph-node macrophages obtained from patients with ovarian and uterine cancer, respectively, expressed far higher levels of basal PCA than the corresponding cell populations from patients with benign tumors (p less than 0.001). PCA of blood mononuclear cells from patients with ovarian, but not with uterine cancer, was significantly higher (p less than 0.001) than that of control cells. High levels of D-dimer, a specific product derived from plasmin-induced degradation of stabilized fibrin, were found in all ascitic fluids and in all plasma samples but one from patients with ovarian cancer. In contrast, all controls and all uterine cancer patients but one had normal plasma D-dimer. Our findings suggest that local activation of host macrophages for PCA production might contribute to fibrin formation within the tumoral mass. In advanced cancer, blood monocytes may also be activated to produce PCA and thus contribute to activation of intravascular coagulation and, possibly, to thrombo-embolic complications frequently associated with disseminated malignancy.

The inflammatory system has been implicated in the pathophysiology of a variety of psychiatric conditions. Individuals with PTSD, depression, and other fear-and anxiety-related disorders exhibit alterations in peripheral circulating inflammatory markers, suggesting dysregulation of the inflammatory system. The relationship between inflammation and PTSD has been investigated almost exclusively in the periphery, and has not been extensively explored in human postmortem brain tissue. Interleukins (ILs) represent a subtype of cytokines and are key signaling proteins in the immune and inflammatory systems. Based on prior research implicating IL signaling in PTSD and depression, we performed a preliminary investigation of IL gene expression in a region of the cortex involved in emotion regulation and PTSD, the dorsolateral prefrontal cortex (dlPFC), using tissue from the newly established VA National PTSD Brain Bank. Gene expression analyses were conducted on post-mortem tissue from the dlPFC from 50 donors: 13 controls, 12 PTSD cases, and 25 depressed cases. RNA was extracted from frozen dlPFC tissue, reverse transcribed to cDNA, and quantitative polymerase chain reaction (qPCR) was performed to assess gene *

Dense tumor innervation is associated with enhanced cancer progression and poor prognosis. We observed innervation in breast, prostate, pancreatic, lung, liver, ovarian, and colon cancers. Defining innervation in high-grade serous ovarian carcinoma (HGSOC) was a focus since sensory innervation was observed whereas the normal tissue contains predominantly sympathetic input. The origin, specific nerve type, and the mechanisms promoting innervation and driving nerve-cancer cell communications in ovarian cancer remain largely unknown. The technique of neuro-tracing enhances the study of tumor innervation by offering a means for identification and mapping of nerve sources that may directly and indirectly affect the tumor microenvironment. Here, we establish a murine model of HGSOC and utilize image-guided microinjections of retrograde neuro-tracer to label tumor-infiltrating peripheral neurons, mapping their source and circuitry. We show that regional sensory neurons innervate HGSOC tumors. Interestingly, the axons within the tumor trace back to local dorsal root ganglia as well as jugular–nodose ganglia. Further manipulations of these tumor projecting neurons may define the neuronal contributions in tumor growth, invasion, metastasis, and responses to therapeutics.