Biology subjects

Coombs, C.

Publications and source records attributed to Coombs, C..

2 recordsLinked to original sources

bioRxiv2019

Neutrophil swarming in damaged tissue is orchestrated by connexin-dependent calcium signals

Neutrophils are major inflammatory cells that rapidly infiltrate injured tissues to provide antimicrobial functions. A key step in their response is the paracrine release of the attractant LTB4, which switches the migration mode from exploratory patrolling to coordinated swarming. This leads to dense clusters that may further disrupt tissue architecture. The coordination mechanism underpinning neutrophil swarms is elusive. Here we show that neutrophils swarms require mutual reinforcement of damage signalling at the wound core. New biosensors and live imaging in zebrafish revealed that neutrophil chemoattractant synthesis is triggered by a sustained calcium flux upon contact with necrotic tissue and sensing of the damage signal ATP. This calcium alarm signal propagates in the nascent neutrophil cluster through connexin-43 hemichannels, which allow release of intracellular ATP. This enables rapid assembly of a centralised, supracellular chemoattractant source, which is instrumental for coordinated recruitment and maximal cell gathering.

cell biology↗

bioRxiv2019

Oncologic Therapy Shapes the Fitness Landscape of ClonalHematopoiesis

Clonal hematopoiesis (CH) is frequent in cancer patients and associated with increased risk of therapy related myeloid neoplasms (tMN). To define the relationship between CH, oncologic therapy, and tMN progression, we studied 24,439 cancer patients. We show that previously treated patients have increased rates of CH, with enrichment of mutations in DNA Damage Response (DDR) genes (TP53, PPM1D, CHEK2). Exposure to radiation, platinum and topoisomerase II inhibitors have the strongest association with CH with evidence of dose-dependence and gene-treatment interactions. We validate these associations in serial sampling from 525 patients and show that exposure to cytotoxic and radiation therapy imparts a selective advantage specifically in hematopoietic cells with DDR mutations. In patients who progressed to tMN, the clone at CH demarcated the dominant clone at tMN diagnosis. CH mutational features predict risk of therapy-related myeloid neoplasm in solid tumor patients with clinical implications for early detection and treatment decisions.

genetics↗