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Biology subjects

Suppinger, S.

Publications and source records attributed to Suppinger, S..

5 recordsLinked to original sources

In the same cell, the proteome defines cellular state and the transcriptome marks transitions

Bulk transcriptome and proteome correlate only modestly, but this has not been investigated in the same cell or across cell-state changes. Here we introduce a scalable technology that quantifies thousands of proteins and transcripts in the same cell, separating RNA from protein by tip-based C18 capture and pairing full-length RNA sequencing with latest-generation mass spectrometry. In HeLa cells, transcript and protein abundances agree on the broad ranking within a cell (r = 0.45), but do not co-vary across the population (r = 0.038). In pluripotency transitions, only a third of matched transcripts and proteins change synchronously, yet the transcription factors defining each state stay tightly co-regulated. Transcript variance is several-fold larger than protein variance, reflecting transcriptional bursting and mRNA sampling noise. The proteome is thus the stable, low-noise definition of cell state, while the transcriptome marks cellular transitions; consequently, the proteome defines cell-state from far fewer cells.

systems biology↗

Cell heterogeneity and fate bistability drive tissue patterning during intestinal regeneration

Tissue regeneration relies on the ability of cells to undergo de novo patterning. While tissue patterning has been viewed as the transition from initially identical un-patterned cells to an arrangement of different cell types, recent evidence suggests that initial heterogeneities between cells modulate tissue-scale pattern formation. Yet, how such heterogeneities arise and, thereafter, regulate cell type emergence in a population of cells is poorly understood. Using in vivo and in vitro mouse regenerative systems, we identify a critical tissue density that is required to induce heterogeneous inactivation of the mechanosensor YAP1. Experimental and biophysical approaches demonstrate that YAP1 cell-to-cell heterogeneity pre-patterns the first cell fate decision, via both chromatin remodelling and a supracellular feedback between FOXA1 and Delta-Notch signalling. This feedback motif induces cell fate bistability endowing memory to the system and the maintenance of patterns during homeostasis. These findings reveal a generalisable framework in which transient cell-to-cell heterogeneity, regulated by tissue-scale properties, serves as a critical control parameter for the emergence of cell fate and stable patterning during regeneration.

cell biology↗

Dynamics and plasticity of stem cells in the regenerating human colonic epithelium

The human intestinal epithelium is a tissue with rapid turnover. Its complex regenerative process and differentiation trajectories have been challenging to study due to its inaccessibility and lack of temporal sampling. To this end, we developed a workflow to culture adult stem cell-derived human intestinal organoids from single cells to maturation. Extensive characterization of our model system indicated a transient regenerative response, followed by differentiation into all mature cell lineages. This switch is accompanied by a transition between two stem cell states. High-content screening and comparison to in vivo studies revealed that an initial fetal-like state is crucial for achieving successful regeneration, while the subsequent adult-like state is vital for maintaining a balance of cell lineages and continuous support of crypt-morphogenesis. Taken together, this study highlights the extensive plasticity of the intestinal epithelium and paves the way for further studies of human intestinal regeneration and its deregulation in pathologies.

cell biology↗

Open top multi sample dual view light sheet microscope for live imaging of large multicellular systems

Multicellular systems grow over the course of weeks from single cells to tissues or even full organisms composed of several thousands of cells, making live imaging of such samples challenging. To bridge these wide spatiotemporal scales, we present an open top dual view and dual illumination light sheet microscope dedicated for live imaging of large specimens at single cell resolution. The novel configuration of objectives together with a flexible and customizable multi-well mounting system combines dual view with high throughput multi-position imaging. We use the newly developed microscope to image a wide variety of samples and highlight its capabilities to gain quantitative single-cell information in large specimens such as mature intestinal organoids and gastruloids.

developmental biology↗

An intrinsic temporal order of c-Jun N-terminal phosphorylation regulates its activity by orchestrating co-factor recruitment

Protein phosphorylation is a major regulatory mechanism of cellular signalling. The c-Jun proto-oncoprotein is phosphorylated at four residues within its transactivation domain (TAD) by the JNK family kinases, but the functional significance of c-Jun multisite phosphorylation has remained elusive. Here we show that c-Jun phosphorylation by JNK exhibits a defined temporal kinetics, with serine63 and serine73 being phosphorylated more rapidly than threonine91 and threonine93. We identified the positioning of the phosphorylation sites relative to the kinase docking motif, and their primary sequence, as the main factors controlling phosphorylation kinetics. Functional analysis revealed three c-Jun phosphorylation states: unphosphorylated c-Jun recruits the Mbd3 repressor, serine63/73 doubly-phosphorylated c-Jun binds to the Tcf4 co-activator, whereas the fully phosphorylated form disfavours Tcf4 binding attenuating JNK signalling. Thus, c-Jun phosphorylation encodes multiple functional states that drive a complex signalling response from a single JNK input.

biochemistry↗