Effects of immunosuppressive peptidyl-prolyl cis-trans isomerase (PPIase) inhibitors, cyclosporin A, FK506, ascomycin and rapamycin, on hair growth initiation in mouse: immunosuppression is not required for new hair growth

Study of Drug Target Identification and Associated Molecular Mechanisms for the Therapeutic Activity and Hair Follicle Induction of Two Ashwagandha Extracts Having Differential Withanolide Constitutions

Background

Ashwagandha extracts play a significant role in traditional Indian medicine to help treat a wide range of disorders from amnesia, erectile dysfunction, neurodegenerative and cardiovascular diseases, cancer, stress, anxiety, and many more. Ashwagandha root is enriched with bioactive plant metabolites of which withanolides are the most important ones. The concentration and constitution of withanolides primarily determine ashwagandha's potency and pharmacology. Various factors modulate the withanolide constitution in the plant-derived extracts, rendering inconsistent therapeutic efficacy. Standardisation of the extraction protocol and a better understanding of the pharmacology mechanism of different extracts with varied withanolide constitutions is therefore critical for developing reliable, repeatable, and effective ashwagandha-based treatment.

Objectives

Here, we work toward defining indication mechanisms for two varieties of ashwagandha extract-ASHWITH (ASH-Ext1) and Regenolide (ASH-Ext2)-with different proprietary withanolide proportions.

Methods

ASH-Ext1 was studied for antioxidant signaling modulation using HEK293, HeLa, and A549 cells, and ASH-Ext2 was studied for subcellular drug targets associated with the reactivation and longevity of human hair follicles, using primary human hair follicle dermal papilla cells (HFDPCs).

Results

Study findings support the antioxidant activity and Nrf2 signaling modulation by ASH-Ext1 in various cell models. Of note, ASH-Ext2 was found to increase β-catenin and telomerase reverse transcriptase (TERT) protein expression levels in HFDPCs.

Conclusion

The results of drug target modulation show us that the withanolide constitution associated with different extraction protocols influences the pharmacological potential of the extract significantly and points to the value of standardisation not only of total withanolide content but also of internal withanolide proportions.

Tacrolimus in Dermatology

Background:

Tacrolimus (FK 506), a metabolite of the fungus Streptomyces tsukubaensis, is an anti-T-cell drug. It acts by inhibiting the production of IL-2, IL-3, IL-4, TNFα, and GM-CSF. More potent and with slightly less secondary effects than cyclosporine, it has been the object of considerable interest, especially in conditions that could benefit from the latter.

Objective:

In psoriasis, a placebo-controlled double-blind study has shown oral tacrolimus at 0.1 mg/kg/day to be effective in controlling recalcitrant lesions. In human, small studies have reported tacrolimus ointment to be effective in controlling acute contact dermatitis. Short-term trials of topical tacrolimus in the treatment of atopic dermatitis have recently shown excellent results in both adults and children. In animal studies of hair growth disorders, topical tacrolimus induces anagen and protects from chemotherapy-induced alopecia. Animal studies with the ointment for the prevention of skin graft rejection, lupus dermatoses, and skin papilloma formation have also shown to be promising.

Conclusions:

There are case reports of pyoderma gangrenosum, Sezary's syndrome, and Behçet's disease successfully treated with oral tacrolimus but, because of their small number, they remain anecdotal at this point.

Mycophenolate antagonizes IFN-γ-induced catagen-like changes via β-catenin activation in human dermal papilla cells and hair follicles

Recently, various immunosuppressant drugs have been shown to induce hair growth in normal hair as well as in alopecia areata and androgenic alopecia; however, the responsible mechanism has not yet been fully elucidated. In this study, we investigate the influence of mycophenolate (MPA), an immunosuppressant, on the proliferation of human dermal papilla cells (hDPCs) and on the growth of human hair follicles following catagen induction with interferon (IFN)-γ. IFN-γ was found to reduce β-catenin, an activator of hair follicle growth, and activate glycogen synthase kinase (GSK)-3β, and enhance expression of the Wnt inhibitor DKK-1 and catagen inducer transforming growth factor (TGF)-β2. IFN-γ inhibited expression of ALP and other dermal papillar cells (DPCs) markers such as Axin2, IGF-1, and FGF 7 and 10. MPA increased β-catenin in IFN-γ-treated hDPCs leading to its nuclear accumulation via inhibition of GSK3β and reduction of DKK-1. Furthermore, MPA significantly increased expression of ALP and other DPC marker genes but inhibited expression of TGF-β2. Therefore, we demonstrate for the first time that IFN-γ induces catagen-like changes in hDPCs and in hair follicles via inhibition of Wnt/β-catenin signaling, and that MPA stabilizes β-catenin by inhibiting GSK3β leading to increased β-catenin target gene and DP signature gene expression, which may, in part, counteract IFN-γ-induced catagen in hDPCs.

Activation of AR sensitizes breast carcinomas to NVP-BEZ235's therapeutic effect mediated by PTEN and KLLN upregulation

NVP-BEZ235 is a newly developed dual PI3K/mTOR inhibitor, being tested in multiple clinical trials, including breast cancer. NVP-BEZ235 selectively induces cell growth inhibition in a subset, but not all, breast cancer cell lines. However, it remains a challenge to distinguish between sensitive and resistant tumors, particularly in the pretreatment setting. Here, we used ten breast cancer cell lines to compare NVP-BEZ235 sensitivity and in the context of androgen receptor (AR) activation during NVP-BEZ235 treatment. We also used female SCID mice bearing breast tumor xenografts to investigate the beneficial effect of dihydrotestosterone/NVP-BEZ235 combination treatment compared with each alone. We found that AR-positive breast cancer cell lines are much more sensitive to NVP-BEZ235 compared with AR-negative cells, regardless of PTEN or PI3KCA status. Reintroducing AR expression in NVP-BEZ235 nonresponsive AR-negative cells restored the response. DHT/NVP-BEZ235 combination not only resulted in a more significant growth inhibition than either drug alone, but also achieved tumor regression and complete responses for AR(+)/ER(+) tumors. This beneficial effect was mediated by dihydrotestosterone (DHT)-induced PTEN and KLLN expression. Furthermore, DHT could also reverse NVP-BEZ235-induced side effects such as skin rash and weight loss. Our data suggest that AR expression may be an independent predictive biomarker for response to NVP-BEZ235. AR induction could add benefit during NVP-BEZ235 treatment in patients, especially with AR(+)/ER(+) breast carcinomas.

Mammalian target of rapamycin complex 1 (mTORC1) may modulate the timing of anagen entry in mouse hair follicles

Mammalian target of rapamycin (mTOR) is a central regulator of cell proliferation and survival. There is limited evidence that mTOR influences hair follicles (HFs), which undergo cycles of quiescence (telogen), growth (anagen) and regression (catagen). We sought to investigate whether mTOR, in particular mTOR complex 1 (mTORC1), regulates the hair growth cycle by employing biochemical, immunohistochemical and functional approaches in vivo. Here, we demonstrate that quantitative analysis of mTORC1 kinase activity shows phase-dependent changes, and phosphorylated mTOR at S2448 (p-mTOR) was localized in certain sites of HFs in a phase-dependent manner. These results were indicative of mTOR's role in hair growth initiation. Finally, in a pharmacological challenge in vivo using the specific mTORC1 inhibitor, rapamycin, hair cycle initiation was delayed, suggesting a functional relevance of mTORC1 in anagen entry. Based on our findings, we propose that mTORC1 may participate in hair cycle regulation, namely the timing of anagen initiation.

The basic science of hair biology: what are the causal mechanisms for the disordered hair follicle?

A hair disorder can be difficult to define, but patients are typically motivated to seek treatment when their hair growth patterns are significantly different from their cultural group or when growth patterns change significantly. The causes of hair disorders are many and varied, but fundamentally the disorder is a consequence of aberrant alterations of normal hair biology. The potential trigger factors for hair disorders can be attributed to inflammation, genetics, the environment, or hormones, of which the relative contributions vary for different diagnoses, between individuals, and over time. This article discusses the causal mechanisms for the disordered hair follicle.

Identification of novel hair-growth inducers by means of connectivity mapping

The aim of this study was to identify novel inducers of hair growth using gene expression profiling at various stages of hair-growth induction. First, we analyzed gene expression at the onset of hair growth in mice induced by cyclosporin A (CsA), a well-known hair-growth inducer, using DNA microarray analysis. The results unveiled genes involved in the step-by-step progression of hair growth, including increases in melanin biosynthesis and decreases in immune response at d 2 and the subsequent stimulation of cell proliferation at d 4, followed by the up-regulation of hair specific keratins at d 7 after CsA treatment. With the use of the connectivity map (Cmap), agents that had a similar "gene signature" to that of the profiles of CsA-treated mice were identified. Several agents, including CsA, were identified by the Cmap and were evaluated for hair induction activity in vivo. One of the proposed agents, fluphenazine (from the d 2 signature) actually induced hair growth in vivo (ED(50): 2 mM for single application), and the subsequent application of 5 mM iloprost (from the d 4 signature) significantly enhanced the hair-growth effect of fluphenazine. From these results, Cmap analysis was proven to be a useful method that connects gene expression profiles of complicated biological processes, such as hair-growth induction, to effective agents.

Cyclosporin a promotes hair epithelial cell proliferation and modulates protein kinase C expression and translocation in hair epithelial cells

Cyclosporin A is an immunosuppressive agent known to cause hirsutism. The mechanisms of action that cause hirsutism have not been fully elucidated, however. We have previously reported that several selective protein kinase C inhibitors promote the growth of murine hair epithelial cells and stimulate anagen induction. In this paper, we report on an investigation of the mechanisms of action of hair-growing activity possessed by cyclosporin A from the viewpoint of whether it promotes hair epithelial cell growth or whether it modulates the expression or translocation of protein kinase C isozymes in hair epithelial cells. Our results indicate that cyclosporin A (over a wide dosage range of 1-1000 ng per ml) stimulates cultured murine hair epithelial cell growth to about 150%-160% relative to controls. We also observed growth-promoting effects on murine epidermal keratinocytes (about 140%) at the dose range of 1-100 ng per ml. At high dose ranges above 3 microg per ml, the growth of both cells was inhibited. On the other hand, we found that cyclosporin A reduces the overall expression of protein kinase C alpha, betaI, and betaII in cultured murine hair epithelial cells, and reduces the levels of protein kinase C alpha, betaI, betaII, and eta in the particulate fraction from cultured murine hair epithelial cells. From these results, we speculate that the hair-growing activity of cyclosporin A is at least partially attributable to its growth-promoting influence on hair epithelial cells sequential to its downregulation of some protein kinase C isozymes in hair epithelial cells or inhibition of translocation of some protein kinase C isozymes to the membrane or cytoskeleton of hair epithelial cells.

Topical application of cyclosporin A induces rapid-remodeling of damaged anagen hair follicles produced in cyclophosphamide administered mice

Adult C3H mice which had either anagen IV or anagen VI hair follicles were given the anti-tumor drug cyclophosphamide, and cyclosporin A or minoxidil were topically applied to the mice daily from the 4th day after cyclophosphamide administration. In the mice that had anagen IV-hair follicles, 0.5% cyclosporin A induced very thick and long hairs after 21 days of cyclophosphamide administration, while vehicle and 1% minoxidil induced sparsely visible, short hairs. In the mice which received cyclosporin A, the injured hair follicles seemed to remodel themselves into intact anagen hair follicles and restart the production of hairs, instead of shifting to telogen. In the mice that had anagen VI-hair follicles at the time of cyclophosphamide administration, complete alopecia occurred within the first 7 days in all groups. After 14 days of cyclophosphamide administration, hair regrowth was observed in both the 0.5% cyclosporin A-group and the 1% minoxidil- group with the predominant effect over the vehicle. This study shows that anagen hair follicles respond to cyclophosphamide in different ways depending on their stages (IV and VI), and that the damaged anagen IV hair follicles have the potential of remodeling themselves, which is promoted by topical cyclosporin A administration.

Controls of hair follicle cycling

Nearly 50 years ago, Chase published a review of hair cycling in which he detailed hair growth in the mouse and integrated hair biology with the biology of his day. In this review we have used Chase as our model and tried to put the adult hair follicle growth cycle in perspective. We have tried to sketch the adult hair follicle cycle, as we know it today and what needs to be known. Above all, we hope that this work will serve as an introduction to basic biologists who are looking for a defined biological system that illustrates many of the challenges of modern biology: cell differentiation, epithelial-mesenchymal interactions, stem cell biology, pattern formation, apoptosis, cell and organ growth cycles, and pigmentation. The most important theme in studying the cycling hair follicle is that the follicle is a regenerating system. By traversing the phases of the cycle (growth, regression, resting, shedding, then growth again), the follicle demonstrates the unusual ability to completely regenerate itself. The basis for this regeneration rests in the unique follicular epithelial and mesenchymal components and their interactions. Recently, some of the molecular signals making up these interactions have been defined. They involve gene families also found in other regenerating systems such as fibroblast growth factor, transforming growth factor-beta, Wnt pathway, Sonic hedgehog, neurotrophins, and homeobox. For the immediate future, our challenge is to define the molecular basis for hair follicle growth control, to regenerate a mature hair follicle in vitro from defined populations, and to offer real solutions to our patients' problems.