Experimental and computational analyses reveal that environmental restrictions shape HIV-1 spread in 3D cultures

Here, using an integrative experimental and computational approach, Imle et al. show how cell motility and density affect HIV cell-associated transmission in a three-dimensional tissue-like culture system of CD4+ T cells and collagen, and how different collagen matrices restrict infection by cell-free virions

Genomic instability of micronucleated cells revealed by single-cell comparative genomic hybridization.

Nuclear variation in size and shape and genomic instability are hallmarks of dedifferentiated cancer cells. Although micronuclei are a typical long-term consequence of DNA damage, their contribution to chromosomal instability and clonal diversity in cancer disease is unclear. We isolated cancer cells with or without micronuclei to perform genomic analysis. Cell suspensions of HT1080 fibrosarcoma cells from either 2D culture or after isolation from 3D collagen matrix culture were stained with Hoechst 33342 and after classification for presence or absence of a micronucleus via bright-field and epifluorescence microscopy, cells were individually aspirated with a micropipette. Subsequently, whole-genome amplification and single-cell comparative genomic hybridization (CGH) were applied to detect genomic aberrations. The data show a high-fidelity isolation and genome amplification that lacks adverse effects by prior Hoechst 33342 staining. HT1080 cells showed a high degree of divergent amplifications, but neither location nor frequency of aberrations was dependent on 2D or 3D culture conditions or micronucleation. Thus, single-cell selection of defined nuclear states is amenable to single-cell CGH and here provides first insight into the aberration drift and genomic diversity in cancer cells with and without micronuclei

Tailored environments to study motile cells and pathogens

Motile cells and pathogens migrate in complex environments and yet are mostly studied on simple 2D substrates. In order to mimic the diverse environments of motile cells, a set of assays including substrates of defined elasticity, microfluidics, micropatterns, organotypic cultures, and 3D gels have been developed. We briefly introduce these and then focus on the use of micropatterned pillar arrays, which help to bridge the gap between 2D and 3D. These structures are made from polydimethylsiloxane, a moldable plastic, and their use has revealed new insights into mechanoperception in Caenorhabditis elegans, gliding motility of Plasmodium, swimming of trypanosomes, and nuclear stability in cancer cells. These studies contributed to our understanding of how the environment influences the respective cell and inform on how the cells adapt to their natural surroundings on a cellular and molecular level