Doctoral researcher: Yesaswini Komaragiri
Principle investigator: Oliver Otto
Co-supervisors: U. Bornscheuer, V. Liebscher, L. Schild
Interplay of ROS with the mechanical properties of mitochondria, membranes and cells
This project aims to investigate tafazzin-induced (TAZ) cardiolipin remodeling in the mitochondrial membrane of eukaryotic cells, the corresponding alteration in ROS levels and their impact on cell mechanical properties.
Tafazzin is a non‐specific phospholipid‐lysophospholipid transacylase, which is related to the molecular organization of mitochondrial membranes by remodeling cardiolipin, a specific phospholipid of mitochondria . In these processes tafazzin exchanges fatty acids between molecular species, transforms the lipid composition and modifies the membrane curvature in e.g. cardiac mitochondria. Homeostasis of this system is essential for cellular function and malfunction leads to increased numbers of reactive oxygen species (ROS) as well as severe diseases like the Barth syndrome.
While ROS release from mitochondria has already been described as a regulator of actomyosin, a direct link between molecular composition of the cytoskeleton and cellular mechanical properties remains elusive . Here, we apply a novel approach, real-time deformability cytometry (RT-DC) to study the impact of altered ROS levels on the mechanical properties of membranes, mitochondria and entire cells. Measuring intrinsic material properties, RT‐DC is capable to characterize more than 1,000 cells per second label‐free without the need for molecular probes .
RT-DC assays will be carried out using a TAZ knock-out model and corresponding wild-type cells (Prof. Uwe Lendeckel). Simultaneous analysis of transcriptome and lipidome (Prof. Lorenz Schild) will allow for correlation of cell mechanical properties to the molecular and structural state of the cytoskeleton and the membrane composition of organelles. The required statistical analysis and development of a differential-omics network will be carried out in collaboration with the Institute of Biomathemathics (Prof. Volkmar Liebscher). It is planned to utilize this network to investigate the interplay of mitochondria modification by different ROS (e.g. H202), disturbance of the respiratory chain and changes to the cytoskeleton.
 Schlame M. “Cardiolipin remodeling and the function of tafazzin” Biochimica et Biophysica Acta (2013)
 Muliyil S. and Narasimha M. “Mitochondrial ROS regulates cytoskeletal and mitochondrial remodeling to tune cell and tissue dynamics in a model for wound healing” Developmental Cell (2014)
 Otto O. et al. “Real-time deformability cytometry: on-the-fly cell mechanical phenotyping” Nature Methods (2015)