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Johansson, E. M. V.

Publications and source records attributed to Johansson, E. M. V..

3 recordsLinked to original sources

Integration of hyperspectral imaging and transcriptomics from individual cells with HyperSeq

Microscopy and omics are complementary approaches to probe the molecular state of cells in health and disease, combining granularity with scalability. While important advances have been achieved over the last decade in each area, integrating both imaging- and sequencing-based assays on the same cell has proven challenging. In this study, a new approach called HyperSeq that combines hyperspectral autofluorescence imaging with transcriptomics on the same cell is demonstrated. HyperSeq was applied to Michigan Cancer Foundation 7 (MCF-7) breast cancer cells and identified a subpopulation of cells exhibiting bright autofluorescence rings at the plasma membrane in optical channel 13 ({lambda}ex = 431 nm,{lambda} em = 594 nm). Correlating the presence of a ring with the gene expression in the same cell indicated that ringed cells are more likely to express hallmark genes of apoptosis and less likely to express genes associated with ATP production. Further, correlation of cell morphology with gene expression suggested that multiple members of the spliceosome were downregulated in larger MCF-7 cells. Multiple genes were evenly expressed across cell sizes but also exhibited higher usage of specific exons in larger or smaller cells. Finally, correlation between gene expression and fluorescence within the spectral range of Nicotinamide adenine dinucleotide hydrogen (NADH) provided insight into the metabolic states of MCF-7 cells. These observations provided a link between the cells optical spectrum and its internal molecular state, demonstrating the utility of HyperSeq to study cell biology at single cell resolution by integrating spectral, morphological and transcriptomic analyses into a single, streamlined workflow.

bioinformatics↗

The intracellular lifestyle of an archaeal symbiont

DPANN Archaea are a diverse group of organisms typically characterised by small cells and reduced genomes. To date, all cultivated DPANN Archaea are ectosymbionts that require direct cell contact with an archaeal host species for proliferation. However, the dynamics of DPANN - host interactions and the impacts of these interactions on the host species are poorly understood. Here, we show that one DPANN archaeon (Candidatus Nanohaloarchaeum antarcticus) engages in parasitic interactions with its host (Halorubrum lacusprofundi) that result in host cell lysis. Our data also suggest that these interactions involve invasion of the host cell by the nanohaloarchaeon. This is the first reported instance of such a predatory-like lifestyle amongst Archaea and indicates that some DPANN Archaea may interact with host populations in a manner similar to viruses.

microbiology↗

Single cell genotyping of matched bone marrow and peripheral blood cells in treatment naive and AZA-treated MDS and CMML

Progressively acquired somatic mutations in hematopoietic stem cells are central to pathogenesis in myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML). They can lead to proliferative advantages, impaired differentiation and progressive cytopenias. MDS or CMML patients with high-risk disease are treated with hypomethylating agents including 5-azacytidine (AZA). Clinical improvement does not require eradication of mutated cells and may be related to improved differentiation capacity of mutated hematopoietic stem and progenitor cells (HSPCs). However, the contribution of mutated HSPCs to steadystate hematopoiesis in MDS and CMML is unclear. To address this, we characterised the somatic mutations of individual stem, progenitor (common myeloid progenitor, granulocyte monocyte progenitor, megakaryocyte erythroid progenitor), and matched circulating (monocyte, neutrophil, naive B cell) haematopoietic cells in treatment naive and AZA-treated MDS and CMML via high-throughput single cell genotyping. The mutational burden was similar across multiple hematopoietic cell types, and even the most mutated stem and progenitor clones maintained their capacity to differentiate to mature myeloid and, in some cases, lymphoid cell types in vivo. Our data show that even highly mutated HSPCs contribute significantly to circulating blood cells in MDS and CMML, prior to and following AZA treatment. Key points* Highly mutated HSPCs contribute significantly to circulating blood cells in MDS and CMML, prior to and following AZA treatment. * The mutational burden in matched bone marrow and peripheral blood cells in MDS and CMML was similar throughout myelopoiesis.

cancer biology↗