bims-ciryme 2024-05-12 papers

Issue of 2024‒05‒12
four papers selected by
Gabriela Da Silva Xavier, University of Birmingham

Nat Commun. 2024 May 07. 15(1): 3840

tauFisher predicts circadian time from a single sample of bulk and single-cell pseudobulk transcriptomic data.

Junyan Duan, Michelle N Ngo, Satya Swaroop Karri, Lam C Tsoi, Johann E Gudjonsson, Babak Shahbaba, John Lowengrub, Bogi Andersen.

As the circadian clock regulates fundamental biological processes, disrupted clocks are often observed in patients and diseased tissues. Determining the circadian time of the patient or the tissue of focus is essential in circadian medicine and research. Here we present tauFisher, a computational pipeline that accurately predicts circadian time from a single transcriptomic sample by finding correlations between rhythmic genes within the sample. We demonstrate tauFisher's performance in adding timestamps to both bulk and single-cell transcriptomic samples collected from multiple tissue types and experimental settings. Application of tauFisher at a cell-type level in a single-cell RNAseq dataset collected from mouse dermal skin implies that greater circadian phase heterogeneity may explain the dampened rhythm of collective core clock gene expression in dermal immune cells compared to dermal fibroblasts. Given its robustness and generalizability across assay platforms, experimental setups, and tissue types, as well as its potential application in single-cell RNAseq data analysis, tauFisher is a promising tool that facilitates circadian medicine and research.

DOI: https://doi.org/10.1038/s41467-024-48041-6

Curr Biol. 2024 Apr 30. pii: S0960-9822(24)00511-6. [Epub ahead of print]

A subclass of evening cells promotes the switch from arousal to sleep at dusk.

Matthew P Brown, Shubha Verma, Isabelle Palmer, Adler Guerrero Zuniga, Anuradha Mehta, Clark Rosensweig, Mehmet F Keles, Mark N Wu.

Animals exhibit rhythmic patterns of behavior that are shaped by an internal circadian clock and the external environment. Although light intensity varies across the day, there are particularly robust differences at twilight (dawn/dusk). These periods are also associated with major changes in behavioral states, such as the transition from arousal to sleep. However, the neural mechanisms by which time and environmental conditions promote these behavioral transitions are poorly defined. Here, we show that the E1 subclass of Drosophila evening clock neurons promotes the transition from arousal to sleep at dusk. We first demonstrate that the cell-autonomous clocks of E2 neurons primarily drive and adjust the phase of evening anticipation, the canonical behavior associated with "evening" clock neurons. We next show that conditionally silencing E1 neurons causes a significant delay in sleep onset after dusk. However, rather than simply promoting sleep, activating E1 neurons produces time- and light-dependent effects on behavior. Activation of E1 neurons has no effect early in the day but then triggers arousal before dusk and induces sleep after dusk. Strikingly, these activation-induced phenotypes depend on the presence of light during the day. Despite their influence on behavior around dusk, in vivo voltage imaging of E1 neurons reveals that their spiking rate and pattern do not significantly change throughout the day. Moreover, E1-specific clock ablation has no effect on arousal or sleep. Thus, we suggest that, rather than specifying "evening" time, E1 neurons act, in concert with other rhythmic neurons, to promote behavioral transitions at dusk.

Keywords: Drosophila; circadian; evening cells; sleep

DOI: https://doi.org/10.1016/j.cub.2024.04.039

Cell. 2024 May 02. pii: S0092-8674(24)00410-0. [Epub ahead of print]

Circadian tumor infiltration and function of CD8+ T cells dictate immunotherapy efficacy.

The quality and quantity of tumor-infiltrating lymphocytes, particularly CD8+ T cells, are important parameters for the control of tumor growth and response to immunotherapy. Here, we show in murine and human cancers that these parameters exhibit circadian oscillations, driven by both the endogenous circadian clock of leukocytes and rhythmic leukocyte infiltration, which depends on the circadian clock of endothelial cells in the tumor microenvironment. To harness these rhythms therapeutically, we demonstrate that efficacy of chimeric antigen receptor T cell therapy and immune checkpoint blockade can be improved by adjusting the time of treatment during the day. Furthermore, time-of-day-dependent T cell signatures in murine tumor models predict overall survival in patients with melanoma and correlate with response to anti-PD-1 therapy. Our data demonstrate the functional significance of circadian dynamics in the tumor microenvironment and suggest the importance of leveraging these features for improving future clinical trial design and patient care.

Keywords: BMAL1; CAR T therapy; PD-1; chronotherapy; circadian; immune checkpoint blockade; immunology; melanoma; tumor-infiltrating leukocyte

DOI: https://doi.org/10.1016/j.cell.2024.04.015

JCI Insight. 2024 May 08. pii: e177697. [Epub ahead of print]9(9):

Circadian transcriptome of pancreatic adenocarcinoma unravels chronotherapeutic targets.

Deepak Sharma, Darbaz Adnan, Mostafa K Abdel-Reheem, Ron C Anafi, Daniel D Leary, Faraz Bishehsari.

Pancreatic ductal adenocarcinoma (PDA) is a lethal cancer characterized by a poor outcome and an increasing incidence. A significant majority (>80%) of newly diagnosed cases are deemed unresectable, leaving chemotherapy as the sole viable option, though with only moderate success. This necessitates the identification of improved therapeutic options for PDA. We hypothesized that there are temporal variations in cancer-relevant processes within PDA tumors, offering insights into the optimal timing of drug administration - a concept termed chronotherapy. In this study, we explored the presence of the circadian transcriptome in PDA using patient-derived organoids and validated these findings by comparing PDA data from The Cancer Genome Atlas with noncancerous healthy pancreas data from GTEx. Several PDA-associated pathways (cell cycle, stress response, Rho GTPase signaling) and cancer driver hub genes (EGFR and JUN) exhibited a cancer-specific rhythmic pattern intricately linked to the circadian clock. Through the integration of multiple functional measurements for rhythmic cancer driver genes, we identified top chronotherapy targets and validated key findings in molecularly divergent pancreatic cancer cell lines. Testing the chemotherapeutic efficacy of clinically relevant drugs further revealed temporal variations that correlated with drug-target cycling. Collectively, our study unravels the PDA circadian transcriptome and highlights a potential approach for optimizing chrono-chemotherapeutic efficacy.

Keywords: Bioinformatics; Drug screens; Oncogenes; Oncology; Therapeutics

DOI: https://doi.org/10.1172/jci.insight.177697