Probes for INS

Patients with primary solid malignancies frequently exhibit signs of systemic inflammation. Notably, elevated levels of neutrophils and their associated soluble mediators are regularly observed in cancer patients, and correlate with reduced survival and increased metastasis formation. Recently, we demonstrated a mechanistic link between mammary tumor-induced IL17-producing γδ T cells, systemic expansion of immunosuppressive neutrophils and metastasis formation in a genetically engineered mouse model for invasive breast cancer. How tumors orchestrate this systemic inflammatory cascade to facilitate dissemination remains unclear. Here we show that activation of this cascade relies on CCL2-mediated induction of IL1β in tumor-associated macrophages. In line with these findings, expression of CCL2 positively correlates with IL1Β and macrophage markers in human breast tumors. We demonstrate that blockade of CCL2 in mammary tumor-bearing mice results in reduced IL17 production by γδ T cells, decreased neutrophil expansion and enhanced CD8+ T cell activity. These results highlight a new role for CCL2 in facilitating the breast cancer-induced pro-metastatic systemic inflammatory γδ T cell – IL17 – neutrophil axis.

As tumour protein 53 (p53) isoforms have tumour promoting, migration and inflammatory properties, this study investigated whether p53 isoforms contributed to glioblastoma progression. The expression levels of full-length TP53α (TAp53α) and six TP53 isoforms were quantitated by RT-qPCR in 89 glioblastomas and correlated with TP53 mutation status, tumour-associated macrophage content and various immune cell markers. Elevated levels of Δ133p53β mRNA characterised glioblastomas with increased CD163-positive macrophages and wild-type TP53. In situ based analyses found Δ133p53β expression localised to malignant cells in areas with increased hypoxia, and in cells with the monocyte chemoattractant protein C-C motif chemokine ligand 2 (CCL2) expressed. Tumours with increased Δ133p53β had increased numbers of cell positive for macrophage colony stimulating factor 1 receptor (CSF1R) and programmed death ligand 1 (PDL1). In addition, cells expressing a murine 'mimic' of Δ133p53 (Δ122p53) were resistant to temozolomide treatment and oxidative stress. Our findings suggest elevated Δ133p53β is an alternative pathway to TP53 mutation in glioblastoma that aids tumour progression by promoting an immunosuppressive and chemoresistant environment. Adding Δ133p53β to a TP53 signature along with TP53 mutation status will better predict treatment resistance in glioblastoma.

The dynamics and interactions between stem cell pools in the hair follicle (HF), sebaceous gland (SG), and interfollicular epidermis (IFE) of murine skin are still poorly understood. In this study, we used multicolor lineage tracing to mark Lgr6-expressing basal cells in the HF isthmus, SG, and IFE. We show that these Lgr6⁺ cells constitute long-term self-renewing populations within each compartment in adult skin. Quantitative analysis of clonal dynamics revealed that the Lgr6⁺ progenitor cells compete neutrally in the IFE, isthmus, and SG, indicating population asymmetry as the underlying mode of tissue renewal. Transcriptional profiling of Lgr6⁺ and Lgr6⁻ cells did not reveal a distinctLgr6-associated gene expression signature, raising the question of whether Lgr6expression requires extrinsic niche signals. Our results elucidate the interrelation and behavior of Lgr6⁺ populations in the IFE, HF, and SG and suggest population asymmetry as a common mechanism for homeostasis in several epithelial skin compartments.

We describe convergent evidence from transcriptomics, morphology, and physiology for a specialized GABAergic neuron subtype in human cortex. Using unbiased single-nucleus RNA sequencing, we identify ten GABAergic interneuron subtypes with combinatorial gene signatures in human cortical layer 1 and characterize a group of human interneurons with anatomical features never described in rodents, having large 'rosehip'-like axonal boutons and compact arborization. These rosehip cells show an immunohistochemical profile (GAD1+CCK+, CNR1-SST-CALB2-PVALB-) matching a single transcriptomically defined cell type whose specific molecular marker signature is not seen in mouse cortex. Rosehip cells in layer 1 make homotypic gap junctions, predominantly target apical dendritic shafts of layer 3 pyramidal neurons, and inhibit backpropagating pyramidal action potentials in microdomains of the dendritic tuft. These cells are therefore positioned for potent local control of distal dendritic computation in cortical pyramidal neurons.