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Nachiket Vartak

About Nachiket Vartak:
No description specified

SEEK ID: https://seek.lisym.org/people/34

Location:  Germany

Expertise: Hepatocytes, Molecular Biology, Signal transduction, Spatio-temporal Modelling, Systems Biology, in vivo imaging, functional imaging

Tools: confocal microscopy, 3D reconstruction, live cell imaging, image analysis, in vivo 2-photon imaging

ORCID: Not specified

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LiSyM-Krebs Partnering

This generic project is intended to be a forum for all LiSyM partner and external stakeholders interested in participating in the BMBF initiative LiSyM-Krebs.

Programme: LiSyM-Krebs

Public web page: https://www.ptj.de/projektfoerderung/gesundheitsforschung/lisym-krebs

Molecular Steatosis - Imaging & Modeling (LiSyM-MSIM)

Dr. Nachiket Vartak (TU University, Dortmund) investigates the role of a particular protein - the GTPase Rab18 - in initiating NAFLD. He tries to influence Rab18 pharmacologically so that NAFLD is not initiated. Vartak also analyzes how bile acids leave the liver. He hopes to find ways to improve the flow of bile in a liver with dysfunctional bile flow.

Programme: LiSyM: Liver Systems Medicine

Public web page: http://www.lisym.org/our-work/junior-group/the-protein-rab18

Start date: 1st Jan 2016

LiSyM network

This comprises the whole LiSyM network

Programme: LiSyM: Liver Systems Medicine

Public web page: http://www.lisym.org

Start date: 1st Jan 2016

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Intravital microscopy of bile flux
Molecular Steatosis - Imaging & Modeling (LiSyM-MSIM)
No description specified

Creator: Nachiket Vartak

Submitter: Nachiket Vartak

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Intravital dynamic and correlative imaging reveals diffusion‐dominated canalicular and flow‐augmented ductular bile flux
Molecular Steatosis - Imaging & Modeling (LiSyM-MSIM), LiSyM network

Abstract (Expand)

Small‐molecule flux in tissue‐microdomains is essential for organ function, but knowledge of this process is scant due to the lack of suitable methods. We developed two independent techniques that allow … the quantification of advection (flow) and diffusion in individual bile canaliculi and in interlobular bile ducts of intact livers in living mice, namely Fluorescence Loss After Photoactivation (FLAP) and Intravital Arbitrary Region Image Correlation Spectroscopy (IVARICS). The results challenge the prevailing ‘mechano‐osmotic’ theory of canalicular bile flow. After active transport across hepatocyte membranes bile acids are transported in the canaliculi primarily by diffusion. Only in the interlobular ducts, diffusion is augmented by regulatable advection. Photoactivation of fluorescein bis‐(5‐carboxymethoxy‐2‐nitrobenzyl)‐ether (CMNB‐caged fluorescein) in entire lobules demonstrated the establishment of diffusive gradients in the bile canalicular network and the sink function of interlobular ducts. In contrast to the bile canalicular network, vectorial transport was detected and quantified in the mesh of interlobular bile ducts. In conclusion, the liver consists of a diffusion dominated canalicular domain, where hepatocytes secrete small molecules and generate a concentration gradient and a flow‐augmented ductular domain, where regulated water influx creates unidirectional advection that augments the diffusive flux.

Authors: Nachiket Vartak, Georgia Guenther, Florian Joly, Amruta Damle‐Vartak, Gudrun Wibbelt, Jörns Fickel, Simone Jörs, Brigitte Begher‐Tibbe, Adrian Friebel, Kasimir Wansing, Ahmed Ghallab, Marie Rosselin, Noemie Boissier, Irene Vignon‐Clementel, Christian Hedberg, Fabian Geisler, Heribert Hofer, Peter Jansen, Stefan Hoehme, Dirk Drasdo, Jan G. Hengstler

Date Published: 19th Jun 2020

Publication Type: Journal

Intravital dynamic and correlative imaging reveals diffusion-dominated canalicular and flow-augmented ductular bile flux
Molecular Steatosis - Imaging & Modeling (LiSyM-MSIM)

Abstract (Expand)

Small-molecule flux in tissue-microdomains is essential for organ function, but knowledge of this process is scant due to the lack of suitable methods applicable to live animals. We developed a methodology … based on dynamic and correlative imaging for quantitative intravital flux analysis. Application to the liver, challenged the prevailing ‘mechano-osmotic’ theory of canalicular bile flow. After active transport across hepatocyte membranes bile salts are transported in the canaliculi primarily by diffusion. Only in the interlobular ducts, diffusion is augmented by regulatable advection. We corroborate these observations with in silico simulations and pan-species comparisons of lobule size. This study demonstrates a flux mechanism, where the energy invested in transmembrane transport entropically dissipates in a sub-micron scale vessel network.

Authors: Nachiket Vartak, Georgia Guenther, Florian Joly, Amruta Damle-Vartak, Gudrun Wibbelt, Jörns Fickel, Simone Jörs, Brigitte Begher-Tibbe, Adrian Friebel, Kasimir Wansing, Ahmed Ghallab, Marie Rosselin, Noemie Boissier, Irene Vignon-Clementel, Christian Hedberg, Fabian Geisler, Heribert Hofer, Peter Jansen, Stefan Hoehme, Dirk Drasdo, Jan G. Hengstler

Date Published: 26th Sep 2019

Publication Type: Journal

3D visualization of the biliary tree by X-ray phase-contrast computed tomography
Molecular Steatosis - Imaging & Modeling (LiSyM-MSIM)

Abstract

Not specified

Author: Amruta Damle-Vartak

Date Published: 1st Dec 2018

Publication Type: Not specified

Bile micro-infarcts in cholestasis are initiated by rupture of the apical hepatocyte membrane and cause shunting of bile to sinusoidal blood
Model Guided Pharmacotherapy In Chronic Liver Disease (LiSyM-MGP)

Abstract

Not specified

Authors: Ahmed Ghallab, Ute Hofmann, Selahaddin Sezgin, Nachiket Vartak, Reham Hassan, Ayham Zaza, Patricio Godoy, Kai Markus Schneider, Georgia Guenther, Yasser A Ahmed, Aya A Abbas, Verena Keitel, Lars Kuepfer, Steven Dooley, Frank Lammert, Christian Trautwein, Michael Spiteller, Dirk Drasdo, Alan F Hofmann, Peter L M Jansen, Jan G Hengstler, Raymond Reif

Date Published: 13th Aug 2018

Publication Type: Not specified

Single cell polarity in liquid phase facilitates tumour metastasis.
Molecular Steatosis - Imaging & Modeling (LiSyM-MSIM)

Abstract (Expand)

Dynamic polarisation of tumour cells is essential for metastasis. While the role of polarisation during dedifferentiation and migration is well established, polarisation of metastasising tumour cells … during phases of detachment has not been investigated. Here we identify and characterise a type of polarisation maintained by single cells in liquid phase termed single-cell (sc) polarity and investigate its role during metastasis. We demonstrate that sc polarity is an inherent feature of cells from different tumour entities that is observed in circulating tumour cells in patients. Functionally, we propose that the sc pole is directly involved in early attachment, thereby affecting adhesion, transmigration and metastasis. In vivo, the metastatic capacity of cell lines correlates with the extent of sc polarisation. By manipulating sc polarity regulators and by generic depolarisation, we show that sc polarity prior to migration affects transmigration and metastasis in vitro and in vivo.

Authors: A. Lorentzen, P. F. Becker, J. Kosla, M. Saini, K. Weidele, P. Ronchi, C. Klein, M. J. Wolf, F. Geist, B. Seubert, M. Ringelhan, D. Mihic-Probst, K. Esser, M. Roblek, F. Kuehne, G. Bianco, T. O'Connor, Q. Muller, K. Schuck, S. Lange, D. Hartmann, S. Spaich, O. Gross, J. Utikal, S. Haferkamp, M. R. Sprick, A. Damle-Vartak, A. Hapfelmeier, N. Huser, U. Protzer, A. Trumpp, D. Saur, N. Vartak, C. A. Klein, B. Polzer, L. Borsig, M. Heikenwalder

Date Published: 2nd Mar 2018

Publication Type: Not specified

Participant Abstracts LiSyM Retreat 2020
LiSyM network
No description specified

Creator: Nachiket Vartak

Submitter: Nachiket Vartak

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LiSyM Ph.D Postdoc Retreat 2020

Venue : Evangelische Tagungsstätte Hofgeismar, Kassel-Wilhelmshöhe

This young scientist retreat is being organized by the Junior Group Leaders, Madlen Matz-Soja, Matthias König, Ahmed Ghallab and Nachiket Vartak.

Start Date: 29th Jan 2020

End Date: 31st Jan 2020

Event Website: http://bit.ly/lisymretreat2020

Country:  Germany

City: Hofgeismar

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