Thomas Schmidt-Rose

Analysis of UV-B-induced DNA damage and its repair in heat-shocked skin cells.

The heat-shock response is a cellular defence mechanism against environmental stresses that is evolutionarily conserved from bacteria to man. Numerous reports demonstrate the beneficial effects of heat-shock protein induction on cell survival under toxic or oxidative stress, e.g., in cardiac and cerebral ischemia or prior to organ transplantation. However, there is little data on the effects of heat treatment on damage caused by UV irradiation. Applying three independent techniques, we have tested the influence of thermal pretreatment of skin cells (1 h, 43 degrees C) on the initial extent of UV-B-induced DNA damage and its subsequent repair. For cultured human epidermal keratinocytes and dermal fibroblasts we can show reduced levels of nucleotide-excision-repair-associated DNA strand incision in the comet assay. Moreover, immunostaining and flow cytometric quantitation of thymidine dimers immediately and one day after irradiation, respectively, reveal that the initial DNA damage is not (keratinocytes) or only moderately (fibroblasts) lower in heat-shocked cells as compared to untreated controls. However, excision repair of dimers is significantly attenuated during the first 24 h in both cell types. Furthermore, using a modified host-cell reactivation assay, we are able to demonstrate that repair of UV-B-damaged plasmid DNA is lower if the transfected cells are previously heat shocked. In summary, heat treatment (1 h, 43 degrees C) inducing heat-shock proteins reduces nucleotide excision repair of UV-B-mediated DNA lesions in fibroblasts and keratinocytes during the following 24 h. This is not necessarily caused by elevated heat-shock protein levels themselves. Possibly the direct thermal damage of repair enzymes is more severe than the potential protective effects of heat-shock proteins.

Glutathione‐conjugated sulfanylalkanols are substrates for ABCC11 and γ‐glutamyl transferase 1: a potential new pathway for the formation of odorant precursors in the apocrine sweat gland

We have previously shown that precursors of odorous components characteristic of axillary sweat are hardly detectable or undetectable in individuals carrying the 538G > A SNP in the ABCC11 transporter gene. However, it is unclear, whether ABCC11 is directly involved in the transport of these compounds. To approach this question, transport of peptide‐conjugated potential precursors of 3‐methyl‐3‐sulfanylhexanol (3M3SH), a key determinant of axillary malodour, was measured using membrane vesicles of Sf9 insect cells overexpressing human ABCC11. Whilst no ABCC11‐mediated transport was detected for the dipeptide precursor Cys‐Gly‐3M3SH, the glutathione conjugate of 3M3SH (SG‐3M3SH) was robustly taken up by ABCC11 at a transport rate of 0.47 pmol/mg/min. Collectively, these results illuminate SG‐3M3SH as a putative precursor of 3M3SH, which then may undergo intra‐vesicular maturation to generate Cys‐Gly‐3M3SH. Critically, the apocrine sweat gland was demonstrated to express γ‐glutamyl transferase 1 (GGT1) protein, which is known to catalyse the deglutamylation of glutathionyl conjugates. Additionally, we provide evidence that recombinant and isolated hepatic human GGT1 is capable of transforming SG‐3M3SH to Cys‐Gly‐3M3SH in vitro. To sum up, we demonstrate that the functionality of ABCC11 is likely to play an important role in the generation of axillary malodour. Furthermore, we identify GGT1 as a key enzyme involved in the biosynthesis of Cys‐Gly‐3M3SH.

Topically applied L-carnitine effectively reduces sebum secretion in human skin.

Background  Oily skin condition is caused by an excessive sebaceous gland activity, resulting in an overproduction of sebum, giving the skin an undesired shiny, oily appearance.

P53-Dependent UVB Responsiveness of Human Keratinocytes Can Be Altered by Cultivation on Cell Cycle-arrested Dermal Fibroblasts

Abstract In cultured human keratinocytes, the tumor suppressor p53 acts as a control element in the protective response to UVB radiation and is affected by a variety of factors linked to cellular adhesion and differentiation. Because keratinocytes within the epidermis are not a homogeneous population but differ in their proliferative capacity and differentiation status, we compared the UVB responsiveness of primary keratinocyte populations isolated from various skin biopsies using p53 expression as a marker for their sensitivity to UVB. Besides keratinocytes exhibiting a UVB dose- and time-dependent upregulation of p53, keratinocyte populations were detected with high p53 expression levels even without irradiation. Such keratinocytes did not regulate p53 expression in response to UVB. Furthermore their p53-mediated UVB response was influenced by cocultivation with human dermal fibroblasts (HDF) but not with cell cycle-arrested human normal keratinocytes or HaCaT keratinocytes. When these cells were cultivated together with arrested HDF, they did not only reveal increased p53 expression levels after UVB treatment but also a more pronounced transcriptional activation of the p53 downstream target gene p21. These findings indicate that the UVB response of keratinocytes, specifically the activation of the tumor suppressor p53, is heterogeneous and can be affected by growth conditions.

Qualification of a new and precise automatic tool for the assessment of hair diameters in phototrichograms.

Background/purpose: To automatically assess hair growth during cosmetic trials, incorporating parameters such as anagen‐to‐telogen rate, growth rate, and especially hair diameter.

Hair and stress: A pilot study of hair and cytokine balance alteration in healthy young women under major exam stress

Mouse models show that experimental stress mimicking prolonged life-stress exposure enhances neurogenic inflammation, induces adaptive immunity cytokine-imbalance characterized by a shift to Type 1 T-helper cell cytokines and increases apoptosis of epithelial cells. This affects hair growth in otherwise healthy animals. In this study, we investigate whether a prolonged naturalistic life-stress exposure affects cytokine balance and hair parameters in healthy humans. 33 (18 exam, 15 comparison) female medical students with comparable sociobiological status were analyzed during a stressful final examination period, at three points in time (T) 12 weeks apart. T1 was before start of the learning period, T2 between the three-day written exam and an oral examination, and T3 after a 12 week rest and recovery from the stress of the examination period. Assessments included: self-reported distress and coping strategies (Perceived Stress Questionnaire [PSQ], Trier Inventory for the Assessment of Chronic Stress [TICS]), COPE), cytokines in supernatants of stimulated peripheral blood mononucleocytes (PBMCs), and trichogram (hair cycle and pigmentation analysis). Comparison between students participating in the final medical exam at T2 and non-exam students, revealed significantly higher stress perception in exam students. Time-wise comparison revealed that stress level, TH1/TH2 cytokine balance and hair parameters changed significantly from T1 to T2 in the exam group, but not the control. However, no group differences were found for cytokine balance or hair parameters at T2. The study concludes that in humans, naturalistic stress, as perceived during participation in a major medical exam, has the potential to shift the immune response to TH1 and transiently hamper hair growth, but these changes stay within a physiological range. Findings are instructive for patients suffering from hair loss in times of high stress. Replication in larger and more diverse sample populations is required, to assess suitability of trichogram analysis as biological outcome for stress studies.

Efficient sweat reduction of three different antiperspirant application forms during stress‐induced sweating

Stress sweating can occur in everyday situations independently of thermally‐induced perspiration. It is triggered by emotionally challenging situations and leads to underarm wetness and a characteristic unpleasant malodor. In this study, we aimed to determine the long‐term efficacy of three unperfumed antiperspirant (AP) formulas for different application forms (roll‐on, stick, aerosol) against stress‐induced sweating and malodor formation.

Is TH17 immunity altered by chronically perceived stress

Inflammatory injury requires tissue regeneration, a process hampered by chronic stress exposure in many experimental settings. The reported shift of the immune balance towards adaptive humoral immunity reported in chronically stressed mice and man may be the functional link. We here report results obtained in females exposed to exam stress. In these individuals subjective perception of anxiety (state and trait anxiety index – STAI) as well as a nervous mood (multidimensional mood questionnaire – MDMQ) prominently characterized chronic stress perception throughout a twelve week examination preparation and execution period. During the same time period exam participants displayed reduced morning serum cortisol levels prior to exam (exam preparation) and during exam execution when compared to expression levels in participants not exposed to exam stress. They also showed significantly increased serum level of the neurotrophin brain derived neurotrophic factor (BDNF). Correspondingly, the summary score for cytokines conducting the TH17 response differed significantly between exam participants and controls during exam preparation. These results link decreased hypothalamus pituitary adrenal axis function during chronic stress exposure with increased neurotrophin expression and TH17 dominated immunity. Future research will determine relevance for chronic inflammatory diseases driven by respective immune-dysfunction.