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Background Stress is an important cause of skin disease, including hair loss. The hormonal response to stress is due to the HPA axis, which comprises hormones such as corticotropin releasing factor (CRF), adrenocorticotropic hormone (ACTH), and cortisol. Many reports have shown that CRF, a crucial stress hormone, inhibits hair growth and induces hair loss. However, the underlying mechanisms are still unclear. The aim of this study was to examine the effect of CRF on human dermal papilla cells (DPCs) as well as hair follicles and to investigate whether the HPA axis was established in cultured human DPCs. Results CRF inhibited hair shaft elongation and induced early catagen transition in human hair follicles. Hair follicle cells, both human DPCs and human ORSCs, expressed CRF and its receptors and responded to CRF. CRF inhibited the proliferation of human DPCs through cell cycle arrest at G2/M phase and induced the accumulation of reactive oxygen species (ROS). Anagen-related cytokine levels were downregulated in CRF-treated human DPCs. Interestingly, increases in proopiomelanocortin (POMC), ACTH, and cortisol were induced by CRF in human DPCs, and antagonists for the CRF receptor blocked the effects of this hormone. Conclusion The results of this study showed that stress can cause hair loss by acting through stress hormones. Additionally, these results suggested that a fully functional HPA axis exists in human DPCs and that CRF directly affects human DPCs as well as human hair follicles under stress conditions.

Antioxidant 1 (ATOX1) protein has been reported to exhibit various protective functions, including antioxidant and chaperone. However, the effects of ATOX1 on the inflammatory response has not been fully elucidated. Thus, we prepared cell permeable Tat-ATOX1 and studied the effects on lipopolysaccharide (LPS)- and 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced inflammation. Experimental results showed that transduced Tat-ATOX1 protein significantly suppressed LPS-induced intracellular reactive oxygen species (ROS). Also, Tat-ATOX1 protein markedly inhibited LPS- and TPA-induced inflammatory responses by decreasing cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) and further inhibited phosphorylation of mitogen activated protein kinases (MAPKs; JNK, ERK and p38) and the nuclear factor-kappaB (NF-κB) signaling pathway. These results indicate that the Tat-ATOX1 protein has a pivotal role in inflammation via inhibition of inflammatory responses, suggesting Tat-ATOX1 protein may offer a therapeutic strategy for inflammation.

roney. Growth hormone regulation of glomerular AT1 angiotensin receptors in adult uninephrectomized male rats. Am J Physiol Renal Physiol 285: F1085-F1091, 2003. First published June 24, 2003 10.1152/ajprenal.00383.2002.-Sex differences exist in the mechanisms initiating early compensatory renal growth after unilateral nephrectomy (UNX); remnant kidney growth is growth hormone (GH) independent in adult female rats and GH dependent in adult male rats. The present study determined whether sex differences also exist in angiotensin type 1 receptor (AT1R) regulation during early remnant kidney (REM) growth after UNX, and if so, whether GH modulates AT1R expression after UNX in the male rat. Scatchard analysis of radioligand binding in glomeruli demonstrated that 48 h post-UNX, AT1R density (Bmax) was significantly decreased by 20% in female REM compared with control kidneys. In contrast, male REM glomerular Bmax was significantly increased by 28% compared with control kidneys. Furthermore, GH-suppressed male rats displayed attenuated REM growth, which was associated with a 35% decrease in AT1R Bmax. Losartan treatment also decreased REM AT1R Bmax by 55%. The activity of mRNA binding proteins that bind to the 5Ј leader sequence of the AT1R was regulated by UNX and GH treatment in an inverse manner to AT1R expression. These findings suggest that in rats 1) there are sex differences in the regulation of glomerular AT1R expression after UNX; 2) the increase in AT1R binding sites in the male REM is regulated by GH and mediates early remnant kidney growth; and 3) AT1R 5Ј leader sequence mRNA binding proteins play a role in UNX and GH regulation of glomerular AT 1Rs in both males and females.

Control of NF-κB release through the inhibition of IκB kinase β (IKKβ) has been identified as a potential target for the treatment of inflammatory and autoimmune diseases. To screen the small molecule compound library against IKKβ, a high-throughput screening (HTS) campaign was carried out using immobilized metal affinity for phosphochemicals (IMAP)-based time-resolved fluorescence resonance energy transfer (TR-FRET) assay. Through serial optimization of assay conditions, the Z' value was achieved at 0.88 from the pilot library screening of the most diverse 7,243 compounds with reconfirmation rate of 63%. The results from this HTS campaign identified three novel scaffolds for the prospective IKKβ inhibitor, such as 7-benzoyl-4-phenylcyclopenta[1,2] oxazine, 1-(thiophen or furan)-2,3-dihydroimidazo[1,5] pyridine and 2-phenyloxazolo[5,4] pyridine. Particularly, 7-benzoyl-4-phenylcyclopenta[1,2] oxazine derivatives presented potent inhibitory activity and selectivity for IKKβ. These findings suggest that the current TR-FRET assay system for IKKβ was successful to identify hits for novel IKKβ inhibitors as a robust, reproducible and sensitive HTS system.