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Carlin, L.

Publications and source records attributed to Carlin, L..

4 recordsLinked to original sources

RNF213 M1-ubiquitinates damaged mitochondria to activate pro-inflammatory NF-κB signaling

Through mitochondrial outer membrane permeabilization (MOMP), mitochondria are central to apoptosis. MOMP is pro-inflammatory, impacting diverse processes including anti-tumor immunity and cellular senescence. Despite this, how damaged mitochondria activate inflammation remains unclear. Recent studies have shown that following MOMP, mitochondria are extensively ubiquitinated activating pro-inflammatory NF-{kappa}B signaling. We identify the E3 ligase, RNF213, as essential for pro-inflammatory mitochondrial ubiquitination following MOMP. RNF213 has an established role in pro- inflammatory, cell-autonomous immunity to bacteria and other pathogens. We discover that RNF213 is required for mitochondrial M1-linked (linear) ubiquitination. Interestingly, this was found to be independent of the canonical M1-ubiquitin ligase complex LUBAC. RNF213 can directly catalyze M1-linked ubiquitination. By promoting mitochondrial M1-linked ubiquitination, RNF213 initiates the recruitment of the essential NF{kappa}B adaptor molecule, NEMO, and subsequently activates pro-inflammatory NF-{kappa}B signaling. Collectively, our findings highlight striking similarities between how cells detect damaged mitochondria and intracellular pathogens, leading to inflammation.

cell biology↗

CYCLOPS: an open end-to-end platform for cyclic multiplex imaging and single-cell phenotyping

Multiplex immunofluorescent imaging enables deep spatial profiling of protein expression in tissues but is often limited by reliance on proprietary reagents, dedicated hardware, and closed analysis ecosystems. Here we present CYCLOPS (Cyclic Open Platform for Spatial Proteomics), an end-to-end, open-source workflow for cyclic multiplex imaging and single-cell phenotyping using standard microscopy infrastructure. CYCLOPS integrates an Arduino-based automated fluidics system, an open-chamber stage insert, and antibody-oligonucleotide conjugation based entirely on published chemistries and off-the-shelf components. We demonstrate robust and reproducible antibody conjugation, high-quality multiplexed staining, and stable imaging across >10 cycles with minimal drift (<1 {micro}m) and consistent fluorescence retention with low signal carry-over. The system supports efficient buffer exchange and consistent performance across multiple markers and imaging rounds. Using confocal microscopy, the workflow is compatible with three-dimensional imaging, enabling multiplexed analysis of volumetric tissue structures. To enable quantitative analysis, we establish an open-source image processing and analysis pipeline for single-cell feature extraction and phenotypic classification, avoiding reliance on proprietary software or black-box workflows. This framework integrates image registration, segmentation, and supervised classification to generate biologically interpretable single-cell data. Together, CYCLOPS provides a flexible and accessible platform for cyclic multiplex imaging, lowering barriers to adoption and enabling broader use of spatial proteomics across diverse research settings. This accessible framework democratizes high-plex imaging by enabling any laboratory with a standard confocal microscope to perform iterative multiplexing without reliance on proprietary reagents or hardware.

Cell Biology↗

Pulmonary natural killer cells control neutrophil intravascular motility and response to acute inflammation

The pulmonary immune system defends a huge surface area directly in contact with the contents of the air we breathe. Neutrophils, the most abundant immune cell in the pulmonary vasculature, are critical to immunity but they are also capable of generating life-threatening pathology. Natural Killer cells are the most highly represented lymphocyte subset in the lung, but relatively little is known about their localization, motility or the specific mechanisms by which they contribute to local homeostasis. Here, we used lung-intravital microscopy to directly visualise and quantify neutrophil and natural killer cell dynamics in the pulmonary vasculature of live mice. This approach revealed unexpected sessile behaviour by intravascular natural killer cells. Interactions with natural killer cells made neutrophils scan the endothelium more slowly over larger distances and reduced the number of neutrophils that accumulated in an LPS-triggered inflammatory challenge. This represents a new paradigm by which natural killer cells contribute to lung physiology by diminishing potentially pathogenic neutrophil accumulation.

immunology↗

Activated BAX/BAK enable mitochondrial inner membrane permeabilisation and mtDNA release during cell death

During apoptosis, pro-apoptotic BAX and BAK are activated, causing mitochondrial outer membrane permeabilisation (MOMP), caspase activation and cell death. However, even in the absence of caspase activity, cells usually die following MOMP. Such caspase-independent cell death is accompanied by inflammation that requires mitochondrial DNA (mtDNA) activation of cGAS-STING signaling. Because the mitochondrial inner membrane is thought to remain intact during apoptosis, we sought to address how matrix mtDNA could activate the cytosolic cGAS-STING signaling pathway. Strikingly, using super-resolution imaging, we show that mtDNA is efficiently released from mitochondria following MOMP. In a temporal manner, we find that following MOMP, BAX/BAK-mediated mitochondrial outer membrane pores gradually widen over time. This allows extrusion of the mitochondrial inner membrane into the cytosol whereupon it permeablises allowing mtDNA release. Our data demonstrate that mitochondrial inner membrane permeabilisation can occur during cell death in a BAX/BAK-dependent manner. Importantly, by enabling the cytosolic release of mtDNA, inner membrane permeabilisation underpins the immunogenic effects of caspase-independent cell death.

cell biology↗