Single nucleus and spatial transcriptomic profiling of healthy human hamstring tendon.

The molecular and cellular basis of health in human tendons remains poorly understood. Among human tendons, hamstring tendon has markedly low pathology and can provide a prototypic healthy tendon reference. The aim of this study was to determine the transcriptomes and location of all cell types in healthy hamstring tendon. Using single nucleus RNA sequencing, we profiled the transcriptomes of 10 533 nuclei from four healthy donors and identified 12 distinct cell types. We confirmed the presence of two fibroblast cell types, endothelial cells, mural cells, and immune cells, and identified cell types previously unreported in tendons, including different skeletal muscle cell types, satellite cells, adipocytes, and undefined nervous system cells. The location of these cell types within tendon was defined using spatial transcriptomics and imaging, and potential transcriptional networks and cell-cell interactions were analyzed. We demonstrate that fibroblasts have the highest number of potential cell-cell interactions in our dataset, are present throughout the tendon, and play an important role in the production and organization of extracellular matrix, thus confirming their role as key regulators of hamstring tendon homeostasis. Overall, our findings underscore the complexity of the cellular networks that underpin healthy human tendon function and the central role of fibroblasts as key regulators of hamstring tendon tissue homeostasis.

Fibronectin matrix assembly and TGFß1 presentation for chondrogenesis of patient derived pericytes for microtia repair.

Tissue engineered cartilage for external ear reconstruction of congenital deformities, such as microtia or resulting from trauma, remains a significant challenge for plastic and reconstructive surgeons. Current strategies involve harvesting autologous costal cartilage or expanding autologous chondrocytes ex vivo. However, these procedures often lead to donor site morbidity and a cell source with limited expansion capacity. Stromal stem cells such as perivascular stem cells (pericytes) offer an attractive alternative cell source, as they can be isolated from many human tissues, readily expanded in vitro and possess chondrogenic differentiation potential. Here, we successfully isolate CD146+ pericytes from the microtia remnant from patients undergoing reconstructive surgery (Microtia pericytes; MPs). Then we investigate their chondrogenic potential using the polymer poly(ethyl acrylate) (PEA) to unfold the extracellular matrix protein fibronectin (FN). FN unfolding exposes key growth factor (GF) and integrin binding sites on the molecule, allowing tethering of the chondrogenic GF transforming growth factor beta 1 (TGFß1). This system leads to solid-phase, matrix-bound, GF presentation in a more physiological-like manner than that of typical chondrogenic induction media (CM) formulations that tend to lead to off-target effects. This simple and controlled material-based approach demonstrates similar chondrogenic potential to CM, while minimising proclivity toward hypertrophy, without the need for complex induction media formulations.

The prognostic utility of pre-treatment neutrophil-to-lymphocyte-ratio (NLR) in colorectal cancer: A systematic review and meta-analysis.

BACKGROUND: Inflammation is a hallmark of cancer, and systemic markers of inflammation are increasingly recognised as negative prognostic factors for clinical outcome. Neutrophil-to-lymphocyte ratio (NLR) is readily available from routine blood testing of patients diagnosed with cancer. METHODS: Peer-reviewed publications from PubMed/MEDLINE, Web of Science and EMBASE were identified according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Hazard ratios (HR) for overall survival (OS) and surrogate endpoints (SE; comprising disease-, recurrence- and progression-free survival) were pooled using a random effects model. Additional analysis was carried out to further investigate NLR as an independent prognostic factor and account for heterogeneity. RESULTS: Seventy-one eligible papers comprising 32,788 patients were identified. High NLR was associated with poor clinical outcomes. Significant publication bias was observed, and larger studies also adjusted for more covariates. Correcting for publication bias in multivariate studies brought our best estimate for true effect size to HR = 1.57 (95% CI 1.39-1.78; p < 0.0001) for OS and to HR = 1.38 (95% CI 1.16-1.64; p = 0.0003) for SE. CONCLUSIONS: NLR is confirmed as an easily available prognostic biomarker in colorectal cancer, despite the limitations of some studies previously reporting this finding. As such, it should be routinely collected in prospective clinical trials. While more standardised and rigorous large-scale studies are needed before high NLR can be fully assessed as an independent predictor of CRC progression and outcome, the data suggest that it may be used to highlight individuals with tumour-promoting inflammatory context.

The antimicrobial peptide defensin cooperates with tumour necrosis factor to drive tumour cell death in Drosophila.

Antimicrobial peptides (AMPs) are small cationic molecules best known as mediators of the innate defence against microbial infection. While in vitro and ex vivo evidence suggest AMPs' capacity to kill cancer cells, in vivo demonstration of an anti-tumour role of endogenous AMPs is lacking. Using a Drosophila model of tumourigenesis, we demonstrate a role for the AMP Defensin in the control of tumour progression. Our results reveal that Tumour Necrosis Factor mediates exposure of phosphatidylserine (PS), which makes tumour cells selectively sensitive to the action of Defensin remotely secreted from tracheal and fat tissues. Defensin binds tumour cells in PS-enriched areas, provoking cell death and tumour regression. Altogether, our results provide the first in vivo demonstration for a role of an endogenous AMP as an anti-cancer agent, as well as a mechanism that explains tumour cell sensitivity to the action of AMPs.