Functional characterization of the epidermal cholinergic system in vitro.
The aim of this study was to analyze the influence of cholinergic and anticholinergic drugs on epidermal physiology using organotypic cocultures (OTCs). Blocking of all acetylcholine receptors (AChRs) by combined treatment with mecamylamine and atropine or treatment with strychnine (blocking alpha9nAChR) for 7-14 days resulted in a complete inhibition of epidermal differentiation and proliferation. Blockage of nicotinic (n)AChR with mecamylamine led to a less pronounced delay in epidermal differentiation and proliferation than blockage of muscarinic (m)AChR with atropine, evidenced by reduced epithelial thickness and expression of terminal differentiation markers like cytokeratin 2e or filaggrin. In OTCs treated with atropine, mecamylamine, or strychnine, we could demonstrate intracellular lipid accumulation in the lower epidermal layers, indicating a severely disturbed epidermal barrier. In addition, we observed prominent acantholysis in the basal and lower suprabasal layers in mecamylamine-, atropine-, and strychnine-treated cultures, accompanied by a decreased expression of cell adhesion proteins. This globally reduced cell adhesion led to cell death via intrinsic activation of apoptosis. In contrast, stimulation of nAChR and mAChR with cholinergic drugs resulted in a significantly thickened epithelium, accompanied by an improved epithelial maturation. In summary, we show that epidermal AChR are crucially involved in the regulation of epidermal homeostasis.
Kurzen
Hjalmar
H
Department of Dermatology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany. hjalmar.kurzen@haut.ma.uni-heidelberg.de
Henrich
Carmen
C
Booken
Dirk
D
Poenitz
Nina
N
Gratchev
Alexei
A
Klemke
Claus-Detlev
CD
Engstner
Monika
M
Goerdt
Sergij
S
Maas-Szabowski
Nicole
N
D000109:Acetylcholine / Q000502:physiology*; D017209:Apoptosis; D001285:Atropine / Q000494:pharmacology; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D002448:Cell Adhesion; D002454:Cell Differentiation; D049109:Cell Proliferation; D018679:Cholinergic Agonists / Q000494:pharmacology; D018680:Cholinergic Antagonists / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000032:analysis / Q000378:metabolism; D051181:Desmosomal Cadherins / Q000032:analysis / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000737:chemistry / Q000502:physiology*; D000091344:Filaggrin Proteins; D006706:Homeostasis; D006801:Humans; D007381:Intermediate Filament Proteins / Q000032:analysis; D053557:Keratin-2 / Q000032:analysis; D050356:Lipid Metabolism; D008055:Lipids / Q000032:analysis; D008464:Mecamylamine / Q000494:pharmacology; D009924:Organ Culture Techniques; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000502:physiology*; D013331:Strychnine / Q000494:pharmacology; D019108:Tight Junctions / Q000737:chemistry / Q000648:ultrastructure
D015415:Biomarkers; D018679:Cholinergic Agonists; D018680:Cholinergic Antagonists; D003598:Cytoskeletal Proteins; D051181:Desmosomal Cadherins; C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; D053557:Keratin-2; D008055:Lipids; D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic; D008464:Mecamylamine; D001285:Atropine; D013331:Strychnine; D000109:Acetylcholine