Biology subjects

Lamia, K. A.

Publications and source records attributed to Lamia, K. A..

6 recordsLinked to original sources

bioRxiv2026

CRY-NLRP3 complexes define a circadian checkpoint controlling inflammasome activation

Innate immune sensors such as the NLRP3 inflammasome can trigger inflammatory responses within minutes, raising the question of how circadian clocks influence such rapid decisions. Here, we identify a protein-level circadian checkpoint that links core clock components to NLRP3 inflammasome activation. We show that NLRP3 associates with the circadian repressors CRY1 and CRY2, forming oscillatory complexes that restrain inflammasome activation and rapidly dissociate upon stimulation. Pharmacological stabilization of CRY proteins preserves CRY-NLRP3 association and attenuates inflammasome assembly, IL-1{beta} secretion and pyroptotic cell death in primary human macrophages. In synchronized macrophages, both NLRP3 inflammasome activation and its inhibition by the NLRP3 inhibitor MCC950 vary with circadian time. Finally, a subset of NLRP3 variants reported in cohorts of patients with Cryopyrin-Associated Periodic Syndromes (CAPS), a group of hereditary fever syndromes caused by mutations in NLRP3, weaken CRY binding and are associated with altered time-of-day patterns of inflammasome activation and MCC950 responsiveness. Together, these findings define CRY-NLRP3 complexes as a circadian checkpoint that modulates inflammasome activity and drug response, revealing time of day as a critical dimension of NLRP3-driven inflammation.

immunology↗

bioRxiv2025

Optimized protocol for processing murine tumor-bearing lung tissue for flow cytometry and single cell RNA-sequencing

NSCLC accounts for approximately 85% of lung cancers, and Kirsten rat sarcoma (KRAS) is the most commonly mutated gene in NSCLC. Although management of NSCLC has advanced markedly in recent years, its heterogeneity and plasticity remain incompletely understood. Single-cell RNA sequencing (scRNA-seq) has become an essential tool for dissecting cellular heterogeneity in complex tissues such as the lung. However, generating high-quality single-cell suspensions from tumor-bearing lung tissue is challenging, particularly during tumor formation when the tissue becomes fibrotic and heterogeneous. A key requirement for successful scRNA-seq is the preparation of viable single cells with minimal processing-induced stress or damage. Here, we present a detailed step-by-step protocol for isolating high-quality single-cell suspensions from both healthy and tumor-bearing mouse lung tissue in a KrasG12D; tdTomato reporter mouse model. The procedure includes tissue perfusion, controlled enzymatic digestion, gentle mechanical dissociation, red blood cell lysis, filtration, and viability assessment, and achieves >85% viable cells prior to scRNA-seq. Finally, the tdTomato+ tumor cells are efficiently isolated by FACS and can be detected as distinct clusters by scRNA-seq using this protocol. SUMMARYWe present a detailed protocol for isolating high-quality single-cell suspensions from both healthy and tumor-bearing murine lung tissue. This protocol can be applied to scRNA-seq, flow cytometry analysis, and primary cell isolation.

cell biology↗

bioRxiv2024

BMAL1-HIF2α heterodimers contribute to ccRCC

Circadian disruption enhances cancer risk, and many tumors exhibit disordered circadian gene expression. We show rhythmic gene expression is unexpectedly robust in clear cell renal cell carcinoma (ccRCC). Furthermore, the clock gene BMAL1 is higher in ccRCC than in healthy kidneys, unlike in other tumor types. BMAL1 is closely related to ARNT, and we show that BMAL1-HIF2 regulates a subset of HIF2 target genes in ccRCC cells. Depletion of BMAL1 reprograms HIF2 chromatin association and target gene expression and reduces ccRCC growth in culture and in xenografts. Analysis of pre-existing data reveals higher BMAL1 in patient-derived xenografts that are sensitive to growth suppression by a HIF2 antagonist (PT2399). We show that BMAL1-HIF2 is more sensitive than ARNT-HIF2 to suppression by PT2399, and increasing BMAL1 sensitizes 786O cells to growth inhibition by PT2399. Together, these findings indicate that an alternate HIF2 heterodimer containing the circadian partner BMAL1 contributes to HIF2 activity, growth, and sensitivity to HIF2 antagonist drugs in ccRCC cells.

cancer biology↗

bioRxiv2022

Circadian disruption enhances HSF1 signaling and tumorigenesis in Kras-driven lung cancer

Disrupted circadian rhythmicity is a prominent feature of modern society and has been designated as a probable carcinogen by the World Health Organization. However, the biological mechanisms that connect circadian disruption and cancer risk remain largely undefined. We demonstrate that exposure to chronic circadian disruption (chronic jetlag, CJL) increases tumor burden in a mouse model of KRAS-driven lung cancer. Molecular characterization of tumors and tumor-bearing lung tissues revealed that CJL enhances the expression of heat shock factor 1 (HSF1) target genes. Consistently, exposure to CJL disrupted the highly rhythmic nuclear trafficking of HSF1 in the lung, resulting in an enhanced accumulation of HSF1 in the nucleus. HSF1 has been shown to promote tumorigenesis in other systems, and we find that pharmacological inhibition of HSF1 reduces the growth of KRAS-mutant human lung cancer cells. These findings implicate HSF1 as a molecular link between circadian disruption and enhanced tumorigenesis.

cell biology↗

bioRxiv2021

CRY2 missense mutations suppress P53 and enhance cell growth

Disruption of circadian rhythms increases the risk of several types of cancer. Mammalian cryptochromes (CRY1 and CRY2) are circadian transcriptional repressors that are related to DNA repair enzymes. While CRYs lack DNA repair activity, they modulate the transcriptional response to DNA damage, and CRY2 can promote SCFFBXL3-mediated ubiquitination of c-MYC and other targets. Here, we characterize five mutations in CRY2 observed in human cancers in The Cancer Genome Atlas. We demonstrate that two orthologous mutations of mouse CRY2 (D325H and S510L) accelerate the growth of primary mouse fibroblasts expressing high levels of c-MYC. Neither mutant affects steady state levels of overexpressed c-MYC, and they have divergent impacts on circadian rhythms and on the ability of CRY2 to interact with SCFFBXL3. Unexpectedly, stable expression of either CRY2 D325H or of CRY2 S510L robustly suppresses P53 target gene expression, suggesting that this is the primary mechanism by which they influence cell growth.

cell biology↗

bioRxiv2020

Circadian benefits of exercise training reflect metabolic and structural flexibility

Structured AbstractO_ST_ABSObjectiveC_ST_ABSExercise is a critical component of a healthy lifestyle and a key strategy for the prevention and management of metabolic disease. Identifying molecular mechanisms underlying adaptation in response to chronic physical activity is of critical interest in metabolic physiology. Circadian rhythms broadly modulate metabolism, including muscle substrate utilization and exercise capacity. Here, we define the molecular and physiological changes induced across the daily cycle by voluntary low intensity daily exercise. MethodsWildtype c57BL6/J male and female mice were housed with or without access to a running wheel for six weeks. Maximum running speed was measured at four different zeitgeber times (ZTs, hours after lights on) using either electrical or manual stimulation to motivate continued running on a motorized treadmill. RNA isolated from plantaris muscles at six ZTs was sequenced to establish the impact of daily activity on genome-wide transcription. Patterns of gene expression were analyzed using Gene Set Enrichment Analysis (GSEA) and Detection of Differential Rhythmicity (DODR). Blood glucose, lactate, and ketones, and muscle and liver glycogen were measured before and after exercise. ResultsWe demonstrate that the use of mild electrical shocks to motivate running negatively impacts maximum running speed and describe a manual method to motivate running in rodent exercise studies. Using this method, we show that time of day influences the increase in exercise capacity afforded by six weeks of voluntary wheel running: when maximum running speed is measured at the beginning of the nighttime active period in mice, there is no measurable benefit from a history of daily voluntary running, while maximum increase in performance occurs at the end of the night. We show that daily voluntary exercise dramatically remodels the muscle circadian transcriptome. Finally, we describe daily rhythms in carbohydrate metabolism associated with the timedependent response to moderate daily exercise. ConclusionsCollectively, these data indicate that chronic nighttime physical activity dramatically remodels daily rhythms of muscle gene expression, which in turn support daily fluctuations in exercise performance.

physiology↗