DFG Research Training Group "TJ-Train" (GRK 2318)
Tight junctions and their proteins
Molecular features and actions in health and disease
Background: Electrophysiological methods have a long tradition in epithelial physiology. However, new developments both in the molecular understanding of the tight junction (TJ) and in the
measuring technology make new approaches possible.
Hypotheses: Combining impedance spectroscopy with specific alterations of partial epithelial resistances will allow us to quantify the contribution of different epithelial components
towards general barrier function of simple and stratified epithelia. Refinement by combining brief, reversible alteration with fast multisinus impedance spectroscopy will generate a method for a
detailed analysis of the mechanisms underlying the action of toxins and drugs.
Aims: This project aims to resolve the
relative contributions of trans- and paracellular pathways as well as stratum corneum components towards barrier function in simple and stratified epithelia, respectively. Healthy and diseased
tissues will be compared and effects of pharmacological treatment on different barrier components will be evaluated.
Methods: Standard molecular biological methods will be used for the knockout/knockdown of specific claudins and for the over-expression of ion channels or TJ components. Resulting cell
clones will be cultivated (standard and 3D cell culture) and used for Ussing-chamber-based impedance spectroscopy. Multisinus technique for fast impedance spectroscopy has recently been
implemented and will be rigorously tested in simple as well as stratified epithelial cell culture. Data will be evaluated by fitting to various equivalent circuit models. Morphological conclusions
from impedance measurements will be cross-validated with optical methods (confocal laserscanning microscopy; transmission electron microscopy).
Thesis project: As part of this PhD project we will derive appropriate equivalent electric circuits by employing established cell culture models for simple and stratified epithelia.
Expression of TJ proteins will be perturbed (e.g. by specific knock-down of TJ proteins or by application of cytokines). The transcellular pathway will be affected by application of ionophores,
poreforming bacterial toxins or by overexpression/activation of ion channels). Trans- and paracellular barrier components will be quantified by modelling impedance spectroscopic data, and
visualized by various optical techniques.
Suggested reading: See Project-related publications,
especially Refs. 2,
3, and 8
PhD doctoral student
MD doctoral student
If a paper is not accessible, please mail to
Milatz S*, Himmerkus N* (*shared first authorship), Wulfmeyer VC, Drewell H, Mutig K, Hou J, Breiderhoff T, Müller D, Fromm M, Bleich
M°, Günzel D° (°shared last authorship) (2017) Mosaic expression of claudins in thick ascending limbs of Henle results in spatial separation of paracellular Na+ and Mg2+
transport. Proc. Natl. Acad. Sci. USA
[PubMed] [WebPage] [PDF+Supplement].
"Paper of the month" 03/2017 of the German Physiological Society
Schmid T, Bogdan M, Günzel D
(2013) Discerning apical and basolateral properties of HT-29/B6 and IPEC-J2 cell layers by impedance spectroscopy, mathematical modeling and machine learning.
PLOS One 8(7): e62913 (printed pages 1-12) [PubMed] [WebPage]
Günzel D, Zakrzewski S, Schmid T, Pangalos M, Wiedenhoeft J, Blasse C, Ozboda C, Krug SM (2012)
From TER to trans- and paracellular resistance: Lessons from impedance spectroscopy. Ann. N.Y. Acad. Sci. 1257: 142-151 [PubMed]
Krug SM, Günzel D, Conrad MP, Rosenthal R, Fromm A, Amasheh S, Schulzke JD, Fromm M (2012) Claudin-17 forms tight junction
channels with distinct anion selectivity.
Cell. Mol. Life Sci. 69(16): 2765-2778 [PubMed] [WebPage]
Milatz S, Krug SM, Rosenthal R,
Günzel D, Müller D, Schulzke JD, Amasheh S*, Fromm M* (*shared last authorship) (2010) Claudin-3 acts as a sealing component of the tight junction for ions of either charge and uncharged
solutes. Biochim. Biophys. Acta Biomembr. 1798: 2048-2057 [PubMed] [WebPage]
Krug SM, Amasheh S, Richter JF, Milatz S, Günzel D, Westphal JK, Huber O, Schulzke JD, Fromm M (2009) Tricellulin forms a barrier
to macromolecules in tricellular tight junctions without affecting ion permeability. Mol. Biol. Cell 20: 3713-3724 [PubMed]
[WebPage] [PDF] [Supplement
text] [Supplement video]
Günzel D, Stuiver M, Kausalya PJ, Haisch L, Krug SM, Rosenthal R, Meij IC, Hunziker W, Fromm M, Müller D (2009a) Claudin-10
exists in six alternatively spliced isoforms which exhibit distinct localization and function. J. Cell Sci. 122: 1507-1517 [PubMed]
Krug SM, Fromm M, Günzel D
(2009) Two-path impedance spectroscopy for measuring paracellular and transcellular epithelial resistance. Biophys. J.
97(8): 2202-2211 [PubMed] [WebPage]
Zeissig S, Bürgel N, Günzel D, Richter JF, Mankertz J, Wahnschaffe U, Kroesen AJ, Zeitz M, Fromm M, Schulzke JD (2007) Changes in
expression and distribution of claudin-2, -5 and -8 lead to discontinuous tight junctions and barrier dysfunction in active Crohn's disease. Gut 56(1):
61-72 [PubMed] [WebPage]
Reiter B, Kraft R, Günzel D, Zeissig S, Schulzke JD, Fromm M, Harteneck C (2006) TRPV4-mediated regulation of epithelial
permeability. FASEB J.
20: 1802-1812 [PubMed] [WebPage]
Tunggal JA*, Helfrich I* (*shared first authorship), Schmitz A, Schwarz H, Günzel D, Fromm M, Kemler R, Krieg T, Niessen CM (2005)
E-cadherin is essential for in vivo epidermal barrier function by regulating tight junctions. EMBO J. 24: 1146-1156 [PubMed]