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Biology subjects

Mertz, K.

Publications and source records attributed to Mertz, K..

3 recordsLinked to original sources

Multimodal single-cell profiling of T cell specificity and reactivity in lung cancer

Adoptive transfer of autologous tumor-infiltrating lymphocyte T cells (TILs) offers one of the most promising approaches for cancer immunotherapy. However, high variability in patient responses highlight the need for an enhanced understanding of the transcriptional phenotypes of TILs and reactivity of their T cell receptors (TCR). Here, we employ single-cell multiomics approaches and TCR functional screening to investigate TILs from treatment-naive non-small cell lung cancer patients. This comprehensive analysis integrates scRNA-seq, scTCR-seq, and scATAC-seq, enabling a high-resolution examination of TILs within lung cancer tissue, as well as the adjacent non-tumor tissue. We apply a cellular functional screening platform to identify reactive TCRs that represent >1,000 TILs and have specificity towards a multitude of targets, including primary tumor cells, neoantigens, tumor-associated antigens, and viral antigens. Tumor-reactive TILs were primarily associated with dysfunctional phenotypes, whereas viral antigen-reactive TCRs were found in effector phenotype clusters. Key marker genes were identified and used to construct a tumor or viral reactivity score. Comparing clones shared in tumor and non-tumor tissue, a higher fraction of exhausted cells was observed in the tumor tissue, whereas non-tumor adjacent tissue possessed more effector cells, thus providing insight into potential sources for therapeutic T cells. Elucidating the specific T cell populations within TILs and their associated TCRs may support strategies to enhance the efficacy of TIL-based therapies. Graphical AbstractO_ST_ABSMultimodal single cell profiling and reactivity testing of TILsC_ST_ABS(A) CD8+ T cells of treatment naive non-small cell lung cancer patients and adjacent lung tissue were isolated by fluorescence-activated cell sorting (FACS) and were then subjected to scRNA-seq + scTCR-seq or scATAC-seq. (B) TCRs were functionally screened using a cellular platform (TnT cells) and target cells (tumor cells, antigen-pulsed antigen-presenting cells, PBMCs) by flow cytometry and deep sequencing. (C) scRNA-seq + scATAC-seq allowed trajectory inference of transcription factors and genes along pseudotime. (D) Gene scores for tumor- and virus-reactivity were developed by combining functional reactivity and transcriptomic profiling for each CD8+ T cell. (E) TIL scRNA-seq pre and post IL-2 treatment in tumor suspension displayed as alluvial plot shows change of clonal cell state composition. O_FIG O_LINKSMALLFIG WIDTH=196 HEIGHT=200 SRC="FIGDIR/small/560863v1_ufig1.gif" ALT="Figure 1"> View larger version (51K): org.highwire.dtl.DTLVardef@12fcc20org.highwire.dtl.DTLVardef@1027dccorg.highwire.dtl.DTLVardef@911711org.highwire.dtl.DTLVardef@18171e5_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

Cryogenic Soft Landing Improves Structural Preservation of Protein Complexes

We describe an apparatus for the cryogenic landing of particles from the ion beam of a mass spectrometer onto transmission electron microscope grids for cryo-electron microscopy. This system also allows for the controlled formation of thin films of amorphous ice on the grid surface. We demonstrate that as compared to room temperature landings, use of this cryogenic landing device greatly improves the structural preservation of deposited protein-protein complexes. Further, landing under cryogenic conditions can increase the diversity of particle orientations, allowing for improved 3D structural interpretation. Finally, we conclude that this approach allows for the direct coupling of mass spectrometry with cryo-electron microscopy.

biochemistry↗

SARS-CoV-2 infects human adipose tissue and elicits an inflammatory response consistent with severe COVID-19

The COVID-19 pandemic, caused by the viral pathogen SARS-CoV-2, has taken the lives of millions of individuals around the world. Obesity is associated with adverse COVID-19 outcomes, but the underlying mechanism is unknown. In this report, we demonstrate that human adipose tissue from multiple depots is permissive to SARS-CoV-2 infection and that infection elicits an inflammatory response, including the secretion of known inflammatory mediators of severe COVID-19. We identify two cellular targets of SARS-CoV-2 infection in adipose tissue: mature adipocytes and adipose tissue macrophages. Adipose tissue macrophage infection is largely restricted to a highly inflammatory subpopulation of macrophages, present at baseline, that is further activated in response to SARS-CoV-2 infection. Preadipocytes, while not infected, adopt a proinflammatory phenotype. We further demonstrate that SARS-CoV-2 RNA is detectable in adipocytes in COVID-19 autopsy cases and is associated with an inflammatory infiltrate. Collectively, our findings indicate that adipose tissue supports SARS-CoV-2 infection and pathogenic inflammation and may explain the link between obesity and severe COVID-19. One sentence summaryOur work provides the first in vivo evidence of SARS-CoV-2 infection in human adipose tissue and describes the associated inflammation.

immunology↗