Michael Krohn

Inhibition of TRPV1 for the treatment of sensitive skin

Please cite this paper as: Inhibition of TRPV1 for the treatment of sensitive skin. Experimental Dermatology 2010; 19: 980–986.

Endogenous Gustatory Responses and Gene Expression Profile of Stably Proliferating Human Taste Cells Isolated From Fungiform Papillae

Investigating molecular mechanisms underlying human taste sensation requires functionally dedicated and at the same time proliferating human taste cells. Here, we isolated viable human fungiform taste papillae cells from biopsy samples, adenovirally transduced proliferation promoting genes, and obtained stably proliferating cell lines. Analysis of gene expression of 1 human taste cell line termed HTC-8 revealed that these cells express 13 TAS2R bitter taste receptor genes, CD36, OXTR encoding oxytocin receptor, as well as genes implicated with signal transduction and cell fate control. Bitter tastants triggered functionally distinct signaling pathways in HTC-8 cells. Salicin elicited phospholipase C-dependent calcium signaling and no cell depolarization. In contrast, stimulation with saccharin, aristolochic acid, or phenylthiocarbamide triggered cell depolarization and phospholipase C-independent calcium influx. Simultaneous stimulation with salicin and saccharin revealed that saccharin can enhance the phospholipase C-dependent response to salicin indicating crosstalk of signaling pathways. Our results show that HTC-8 cells are programmed to bitter taste reception but are also responsive to fatty acids, oxytocin, and somatosensory stimuli, whereas HTC-8 cells are insensitive to compounds representing other basic taste qualities.

A novel TMEM16A splice variant lacking the dimerization domain contributes to calcium‐activated chloride secretion in human sweat gland epithelial cells

Sweating is an important physiological process to regulate body temperature in humans, and various disorders are associated with dysregulated sweat formation. Primary sweat secretion in human eccrine sweat glands involves Ca2+‐activated Cl− channels (CaCC). Recently, members of the TMEM16 family were identified as CaCCs in various secretory epithelia; however, their molecular identity in sweat glands remained elusive. Here, we investigated the function of TMEM16A in sweat glands. Gene expression analysis revealed that TMEM16A is expressed in human NCL‐SG3 sweat gland cells as well as in isolated human eccrine sweat gland biopsy samples. Sweat gland cells express several previously described TMEM16A splice variants, as well as one novel splice variant, TMEM16A(acΔe3) lacking the TMEM16A‐dimerization domain. Chloride flux assays using halide‐sensitive YFP revealed that TMEM16A is functionally involved in Ca2+‐dependent Cl− secretion in NCL‐SG3 cells. Recombinant expression in NCL‐SG3 cells showed that TMEM16A(acΔe3) is forming a functional CaCC, with basal and Ca2+‐activated Cl− permeability distinct from canonical TMEM16A(ac). Our results suggest that various TMEM16A isoforms contribute to sweat gland‐specific Cl− secretion providing opportunities to develop sweat gland‐specific therapeutics for treatment of sweating disorders.

CRISPR in der biotechnologischen Forschung und Entwicklung

The discovery of programmable double-stranded DNA specific nucleases derived from the prokaryotic immunity systems CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) has opened a new era of genome editing and its applications in industrial biotechnology. Simple reprogramming of the DNA-specificity of CRISPR nucleases by RNAs allows the engineering of novel eukaryotic screening or producer cells through gene knock-out, chromosomal deletion and the regulation of gene expression.