LS² Annual Meeting 2021

Welcome Words

Mario Tschan (UNIBE) as chair of the LS² Annual e-Meeting 2021 and Didier Picard as president of LS² will open the meeting

African killifishes shed new light on life history evolution and reveal an important role of the gut microbiota in modulating vertebrate lifespan

Species in nature display a staggering diversity in individual lifespan. From mayfly that live a few hours after hatching, to thousands-year old plants that keep reproducing throughout their life. Lifespan in a given species is limited by external factors, such as predation, infections, starvation, dehydration, etc., as well as by internal factors, including molecular, cellular and tissue damage caused by natural biological processes, such as cell replication and accumulation of aberrant sub-cellular protein aggregates. In my presentation, I will discuss the case of African killifishes, a unique group of fishes that have repeatedly adapted their life cycle to survive in extreme environments, represented by savannah water pools that completely desiccate once a year during the dry season. Among African killifishes, the turquoise killifish (Nothobranchius furzeri) is the shortest-lived species, with a lifespan that ranges from four to eight months. I will describe the life cycle of the turquoise killifish and explain what it means for this fish to undergo “aging”. In the final part of my talk I will present our recent findings on how the gut microbiota plays a causal role in modulating aging and lifespan and how understanding the interaction between adaptive immune system and the microbiota gives us novel insights into the biology of aging and offers new possibilities for future anti-aging therapeutic interventions.

Discovery of the Root Cap Cuticle: Structure and Functions.

During land colonization, plants developed extracellular diffusion barriers, such as cuticle to isolate themselves from the environment. The cuticle is a lipid layer, made of cutin, deposited at the surface of the plant shoot. It prevents the loss of water and nutrients and protect plants against stresses. Plant cuticles have been studied since the 19th century and only characterized in the shoot epidermal cells. A cuticle at the root was not imagined to be compatible with its uptake function. Hence, the specific localization of the cuticle at the epidermis of the aerial organ became a defined feature of the cuticle. However, the intriguing expression of genes involved in cutin biosynthesis at the tip of primary and lateral roots of Arabidopsis has led to the investigation of the cell wall ultrastructure at the root cap cells, the outer cell layer of the root tip.

The root cap cells of young primary roots and lateral roots of Arabidopsis, as well as of other species, are covered by an layer highly similar to the Arabidopsis leaf cuticle. The structure, the composition and the biosynthesis pathway of the root cap cuticle was investigated.  The root cap cuticle of young primary and emerging lateral roots plays important roles in root physiology and development such as diffusion barrier protecting the root meristem from toxic compounds and the reduction of organ adhesion causing a delay in lateral root emergence. 

Until now, plant cuticles of different aerial organs have been exclusively associated with epidermal tissues of the shoot, our discovery of a cuticle at the root cap now challenges this dogma and adds a new element to our understanding of root anatomy, development, and physiology.

Andrea Ablasser 

Sensing DNA as a danger signal through the cGAS-STING pathway

The life of any organism depends on the ability of its cells to recognize and respond to pathogenic microbes. To accomplish this vital task cells rely on intricate signaling pathways that couple sensing of pathogen-associated danger signals to the execution of antimicrobial immune responses. The cGAS-(cGAMP)-STING signaling pathway constitutes a highly conserved innate immune sensing strategy that originated in bacteria to protect from phage infection. In mammals, the pathway detects intracellular DNA to then initiate an antiviral and inflammatory state. It is becoming increasingly apparent that the cGAS-STING pathway plays a critical role in regulating a number of (patho-)physiological processes that fall outside its original function in host defense. As such, activation of this pathway is implicated in several inflammatory disease states where homeostasis is compromised and out-of-context self DNA accumulates, including autoimmunity, cancer, and neurodegeneration. 

In this talk I will present advances in our understanding of the activation and regulation of the cGAS-STING pathway. 

Prisca Liberali

Symmetry breaking and self-organization in intestinal organoids

Multicellular organisms are composed of cells and tissues with identical genomes but different properties and functions. They all develop from one cell to form multicellular structures of astounding complexity. During development, in a series of spatio-temporal coordinated steps, cells differentiate into different cell types and establish tissue-scale architectures and functions. Throughout life, continuous tissue renewal and regeneration is required for tissue homeostasis, which also requires fine-tuned spatio-temporal coordination of cells. I will discuss how cellular interactions generate the specific contexts and spatio-temporal coordination underlying development and regeneration and how we specifically investigate what are the molecular and physical mechanisms that allow a cell, in a tissue, to sense its complex environment, to take individual coordinated decisions. Moreover, I will discuss the molecular mechanisms of intestinal organoid self-organization and the role of cell-to-cell variability in populations of differentiating cells during symmetry breaking. 

Young Scientists' Symposium

Science Communication - but reasonably

The relevance of science communication is underscored by many people’s reaction during the current SARS-CoV-2 pandemic, which is why we have invited the professional science communicator Dr. Lars Dittrich to provide junior researchers with the right methods and tool to communicate their science.

How to best explain to one’s family and friends, what we are doing in the lab all day? How to react to hostilities against to animal testing? Or how to respond to twitter tirades from corona deniers? Packed with tales and practical recommendations, this keynote lecture will be everything but boring.

We will have four rooms to discuss the following topics:

• Room 1: Career corner - "A stepping stone for careers in Life Sciences" (feminno program)
• Room 2: Science Communication 
• Room 3: Start-ups, Entrepreneurship
• Room 4: Academic funding

See all details here and choose one of those rooms during registration.

Preliminary program:

• Welcome and introduction (10 mint)
• Input talk by Jacob Corn: Current status of human genome editing research (10 mint)
• Q&A and Live polling on acceptability and impact of human genome editing (25 mint)
• Input talk by Hervé Chneiweiss: Principles for governing human genome editing (10 mint)
• Q&A and Live polling on governance and responsible research 25 min.
• Conclusions (10 mint)

See all details here

See all our sponsors here

This symposium is organized by Gabriela Kania (UZH) and Marie-Noëlle Giraud (UNIFR) as part of our LS² Cardiovascular Intersection

This symposium is organized by Mark Ibberson (SIB) and Alan Bridge (SIB) as part of our LS² Bioinformatics Intersection - Swiss Institute of Bioinformatics (SIB)

This symposium is organized by Alexander Eggel (UNIBE) and Jörn Dengjel (UNIFR), as part of the  LS² Autophagy Section. 

This Symposium is supported by the Swiss Society for Aging Research (SSFAR).

This symposium is organized by Urs Ziegler (UZH),  Joana Delgado Martins (UZH) and Laure Plantard (FMI) as part of our  LS² Microscopy Intersection

This symposium is organized by Torsten Ochsenreiter (UNIBE) as part of the LS² MCB section

Circulatory factors as regulators of aging and brain function

Brain aging leads to cognitive decline and is the main risk factor for sporadic forms of neurodegenerative diseases including Alzheimer’s disease. While brain cell- and tissue-intrinsic factors are likely key determinants of the aging process recent studies document a remarkable susceptibility of the brain to circulatory factors. Thus, blood borne factors from young mice or humans are sufficient to slow aspects of brain aging and improve cognitive function in old mice and, vice versa, factors from old mice are detrimental for young mice and impair cognition. In trying to understand the molecular basis of these observations we found evidence that the cerebrovasculature is an important target and that brain endothelial cells show prominent age-related transcriptional changes in response to plasma. We discovered that plasma proteins are taken up broadly into the brain and that this process various between individual endothelial cells and with aging. We are exploring the relevance of these findings for neurodegeneration and potential applications towards therapies.

Information about this special session and the finalists of the competition here

Mechanisms of multivesicular endosome biogenesis

Cell surface proteins, including receptors and their ligands, lipids as well as solutes, are endocytosed from the plasma membrane via several pathways that merge in a common early endosome. From there, some components are recycled back to the plasma membrane, or retrieved and returned to the Golgi. Other components, including downregulated receptors, are sorted into the forming intralumenal vesicles (ILVs) of nascent multivesicular endosomes (MVEs). Once formed, MVEs detach — or mature — from early endosomes, and transport ILVs towards late endosomes and lysosomes, where ILVs are degraded together with their protein cargo. Alternatively, MVEs can also undergo fusion with the plasma membrane and secrete their ILVs into the extracellular medium as exosomes. Some of the mechanisms that drive the biogenesis of ILVs, as well as cargo sorting into ILVs or exosomes will be discussed.

See all our sponsors here

This symposium was planned by Philip Skaanderup (Novartis)  is organized by Christian Heinis (EPFL) as part of our partner society: the DMCCB, a division of the Swiss Chemical Society

This symposium is organized by Robbie Joséph Loewith (UNIGE) and Claudio De Virgilio (UNIFR) as part of the LS² MCB Section

This symposium is organized by Thomas Lutz (UZH), as part of the LS² Physiology Section. 

This symposium is organized by Attila Becskei (UNIBAS) and Yolanda Schaerli (UNIL) as part of the LS² Systems Biology section

This symposium is organized by Gabriele Weitz-Schmidt (UNIBAS) as part of our partner society Swiss Society for Experimental Pharmacology - SSEP

Metabolic interactions between the endothelium and the muscle

Angiogenesis, the formation of new blood vessels from existing ones, is initiated by the secretion of growth factors – the vascular endothelial growth factor VEGF is the best described one - from a hypoxic environment. To grow under low oxygen conditions, ECs have unique metabolic characteristics. Indeed, even though they are located next to the blood stream - and therefore have access to the highest oxygen levels - ECs are highly glycolytic. However, when they need to sprout into avascular areas and form new vessels, they upregulate glycolysis even further to fuel migration and proliferation. Suppression of glycolysis via inhibition of the glycolytic regulator PFKFB3 (phosphofructokinase-2/fructose-2,6-bisphosphatase isoform 3) in endothelial cells prevents blood vessel growth in the retina of the mouse pup and also in various models of pathological angiogenesis. While we now know that ECs are metabolically preconditioned to rapidly form new vessels, it remains an outstanding question whether this also holds true in muscle and whether endothelial metabolism can become a target for the treatment of peripheral artery disease. The Laboratory of Exercise and Health aims to investigate whether muscle endothelial cells need to reprogram their metabolism to promote optimal muscle angiogenesis. Moreover, we try to understand how muscle and the endothelium communicate to ensure optimal nutrient and oxygen delivery into the muscle.