DFG Research Training Group "TJ-Train" (GRK 2318)
Tight junctions and their proteins
Molecular features and actions in health and disease
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.
See Project-related publications, especially Refs. 2,
3, and 8
PhD doctoral student
Note to TJ-Train students: 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
"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]
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
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):
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]
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]
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]
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]
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]
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]