Exploring compounds to be used as cosmetic agents that activate peroxisome proliferator-activated receptor alpha.

OBJECTIVE: The human epidermis is formed by the proliferation and differentiation of keratinocytes adjacent to the basement membrane. The outermost layer, the stratum corneum, is equipped with a barrier function that prevents water evaporation, and intercellular lipids play an important role in this barrier function. When the barrier is functioning normally, evaporation is prevented; however, when barrier function is impaired, moisture evaporates, resulting in dry and rough skin. Therefore, maintenance of normal barrier function is critical for maintaining normal skin function. Peroxisome proliferator-activated receptor α (PPARα) is mainly not only involved in lipid metabolism in the liver but is also expressed in the epidermis and is involved in inducing keratinocyte differentiation, promoting lipid production, maintaining barrier function and suppressing skin inflammation. Hence, compounds that activate PPARα are expected to control skin function. Therefore, we identified PPARα activators from among extracts of natural resources that have been approved for use in humans and analysed the effects of these extracts on skin function. METHODS: First, extracts of 474 natural resources were screened using a PPARα activator screening cell line independently constructed in our laboratory. Next, reporter assays were performed using the Gal4-chimera system to evaluate whether these extracts act as ligands for PPARα. We then analysed their effect on primary normal human epidermal keratinocyte cells by using real-time RT-PCR. Finally, we evaluated PPARα activation effect by the combination of these extracts. RESULTS: We identified 36 extracts having the effect of activating PPARα. In particular, #419, a Typha angustifolia spike extract, showed concentration-dependent transcriptional activation through PPARα-LBD and was considered to be likely to contain a compound that is a ligand of PPARα. #419 increased the expression of PPARα target genes and genes related to skin function in primary cultured human epidermal keratinocytes. Finally, the use of #419 in combination with nine extracts increased PPAR activity more than twice as much as #419 alone treatment. CONCLUSIONS: These results showed that the reporter cell line could be useful for discovering extracts of natural resources and that the identified Typha angustifolia spike extract could be used in cosmetics that activate PPARα, which expected to improve skin function.

OBJECTIF: L'épiderme humain se forme grâce à la prolifération et à la différenciation des kératinocytes adjacents à la membrane basale. La couche externe, dite « couche cornée ¼, possède une fonction barrière qui empêche l'évaporation de l'eau, dans laquelle les lipides intercellulaires jouent un rôle important. Lorsque la barrière fonctionne normalement, l'évaporation est évitée ; mais lorsqu'elle est altérée, l'évaporation a lieu et la peau, privée d'hydratation, devient sèche et rêche. Par conséquent, il est capital de maintenir cette fonction barrière normale pour que la peau conserve son fonctionnement normal. Le récepteur alpha activé par proliférateurs de peroxysomes (PPARα) intervient surtout non seulement dans le métabolisme lipidique du foie, mais également dans l'épiderme ; il joue en effet un rôle dans l'induction de la différenciation des kératinocytes, la promotion de la production lipidique, le maintien de la fonction barrière et la suppression de l'inflammation de l'épiderme. Par conséquent, les activateurs du PPAR-α devraient être déterminants pour une bonne fonction cutanée. Nous avons donc identifié des activateurs du PPAR-α parmi des extraits de ressources naturelles dont l'utilisation chez l'homme est approuvée, et nous avons analysé les effets de ces extraits sur la fonction cutanée. MÉTHODES: Tout d'abord, des extraits de 474 ressources naturelles ont été sélectionnés à l'aide d'une lignée cellulaire de détection des activateurs du PPAR-α, construite indépendamment dans notre laboratoire. Ensuite, des tests de gènes rapporteurs ont été effectués à l'aide du système Gal4-chimera pour voir si ces extraits jouaient le rôle de ligands pour le PPAR-α. Nous avons ensuite analysé leur effet sur les cellules kératinocytaires épidermiques humaines normales primaires par RT-PCR en temps réel. Enfin, nous avons évalué l'effet d'activation du PPAR-α par l'association de ces extraits. RÉSULTATS: Nous avons identifié 36 extraits ayant pour effet d'activer le PPAR-α. En particulier, le n° 419, un extrait d'épi de Typha angustifolia, a montré une activation transcriptionnelle dépendante de la concentration par le PPAR-α-LBD et a été considéré comme susceptible de contenir un composé qui est un ligand du PPAR-α. Le n° 419 a augmenté l'expression des gènes cibles du PPAR-α et des gènes liés au fonctionnement de la peau dans les kératinocytes épidermiques humains primaires mis en culture. Enfin, l'utilisation du n° 419 en association avec neuf extraits a augmenté de plus du double l'activité du PPAR par rapport au traitement par le n° 419 seul. CONCLUSIONS: Ces résultats ont montré que la lignée cellulaire rapporteuse pourrait être utile pour découvrir des extraits de ressources naturelles et que l'extrait d'épi de Typha angustifolia identifié pourrait être utilisé dans des cosmétiques qui activent le PPAR-α, ce qui devrait améliorer la fonction cutanée.

Structural Basis for PPARα Activation by 1H-pyrazolo-[3,4-b]pyridine Derivatives.

Small-molecule agonism of peroxisome proliferator-activated receptor α (PPARα), a ligand-activated transcriptional factor involved in regulating fatty acid metabolism, is an important approach for treating dyslipidemia. Here, we determined the structures of the ligand-binding domain (LBD) of PPARα in complex with 1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid derivatives, which were recently identified as PPARα-selective activators with markedly different structures from those of the well-known PPARα agonists fibrates. The crystal structures of the complexes showed that they form a canonical hydrogen-bond network involving helix 12 in the LBD, which is thought to be essential for PPARα activation, as also observed for fibrates. However, the phenyl side chain of the compounds occupies a small cavity between Ile272 and Ile354, which is rarely accessed by fibrates. This unique feature may be essential for subtype selectivity and combine with the well-characterized binding mode of fibrates to improve activity. These findings demonstrate the advantage of using 1H-pyrazolo-[3,4-b]pyridine as a skeleton of PPARα agonists and provide insight into the design of molecules for treating dyslipidemia.

Structural development of 1H-pyrazolo-[3,4-b]pyridine-4-carboxylic acid derivatives as human peroxisome proliferator-activated receptor alpha (PPARα)-selective agonists.

We previously reported that 1H-pyrazolo-[3,4-b]pyridine-4-carboxylic acid derivative 6 is an agonist of human peroxisome proliferator-activated receptor alpha (hPPARα). Here, we prepared a series of 1H-pyrazolo-[3,4-b]pyridine-4-carboxylic acid derivatives in order to examine the structure-activity relationships (SAR). SAR studies clearly indicated that the steric bulkiness of the substituent on 1H-pyrazolo-[3,4-b]pyridine ring, the position of the distal hydrophobic tail part, and the distance between the distal hydrophobic tail part and the acidic head part are critical for hPPARα agonistic activity. These SAR results are somewhat different from those reported for fibrate-class hPPARα agonists. A representative compound (10f) was as effective as fenofibrate in reducing the elevated plasma triglyceride levels in a high-fructose-fed rat model.

Discovery of peroxisome proliferator-activated receptor α (PPARα) activators with a ligand-screening system using a human PPARα-expressing cell line.

Peroxisome proliferator-activated receptor α (PPARα) is a ligand-activated transcription factor that belongs to the superfamily of nuclear hormone receptors. PPARα is mainly expressed in the liver, where it activates fatty acid oxidation and lipoprotein metabolism and improves plasma lipid profiles. Therefore, PPARα activators are often used to treat patients with dyslipidemia. To discover additional PPARα activators as potential compounds for use in hypolipidemic drugs, here we established human hepatoblastoma cell lines with luciferase reporter expression from the promoters containing peroxisome proliferator-responsive elements (PPREs) and tetracycline-regulated expression of full-length human PPARα to quantify the effects of chemical ligands on PPARα activity. Using the established cell-based PPARα-activator screening system to screen a library of >12,000 chemical compounds, we identified several hit compounds with basic chemical skeletons different from those of known PPARα agonists. One of the hit compounds, a 1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid derivative we termed compound 3, selectively up-regulated PPARα transcriptional activity, leading to PPARα target gene expression both in vitro and in vivo Of note, the half-maximal effective concentrations of the hit compounds were lower than that of the known PPARα ligand fenofibrate. Finally, fenofibrate or compound 3 treatment of high fructose-fed rats having elevated plasma triglyceride levels for 14 days indicated that compound 3 reduces plasma triglyceride levels with similar efficiency as fenofibrate. These observations raise the possibility that 1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid derivatives might be effective drug candidates for selective targeting of PPARα to manage dyslipidemia.

Favorable outcome of intraoperative radiotherapy to the primary site in patients with metastatic prostate cancer.

BACKGROUND: The aim of this study was to determine whether local radiotherapy to the prostate by intraoperative radiotherapy (IORT) increases the overall and cancer-specific survival rates of patients with metastatic prostate cancer. METHODS: Between 1993 and 2000, 102 patients with prostate cancer were treated with a combination of (a) IORT of the prostate (25 or 30 Gy per fraction); (b) external beam radiotherapy of the prostate (30 Gy in 10 fractions), starting approximately 1 week post-operatively; and (c) endocrine treatment. Of these, 16 patients had stage D1 disease (D1 IORT group), 32 had stage D2 disease without visceral metastasis (D2 IORT group), and 38 had stage D2 disease without visceral metastasis and did not receive local therapy (D2 control group). Overall and cancer-specific survival rates were compared. RESULTS: The 5- and 10-year cancer-specific survival rates were 75.9 and 52.7 %, respectively, in the (D1 + D2) IORT group and 45.8 and 33.5 %, respectively, in the D2 control group, with cancer-specific survival being significantly longer in the D2 IORT than in the D2 control group (P = 0.030). Univariate and multivariate reduced-rank regression analyses showed that extent of skeletal disease Grade 4 and non-regional lymph node metastasis were significantly prognostic of poorer cancer-specific survival (P < 0.001 each). CONCLUSIONS: Local radiotherapy to the prostate by IORT in patients with metastatic prostate cancer may contribute to better survival, especially in patients without extent of skeletal disease Grade 4 or non-regional lymph node metastasis.

The processus vaginalis transection method is superior to the simple prophylactic procedure for prevention of inguinal hernia after radical prostatectomy.

BACKGROUND: We compared retrospectively the efficacy of two methods for prevention of post-radical prostatectomy inguinal hernia: blunt dissection of the peritoneum at the internal inguinal ring, and isolation of the spermatic cord from the peritoneum (simple prophylactic procedure) and transection of the processus vaginalis. METHODS: Of the 367 patients who underwent open radical retropubic prostatectomy for clinically localized prostate cancer between February 2005 and March 2012 at Saitama Cancer Center Hospital, 344 patients whose follow-up period was more than 2 years were enrolled in this study. Of these patients, 178 patients received the simple prophylactic procedure and 57 underwent processus vaginalis transection. We evaluated the risk factors for inguinal hernia (age; anastomotic stricture post radical prostatectomy; prophylactic procedures for inguinal hernia; previous history of abdominal surgery; previous inguinal hernia surgery; body mass index) using univariate and multivariate analysis. The effects of the two prophylactic procedures on incidence of inguinal hernia were analyzed using Kaplan-Meier plots. RESULTS: The incidence of inguinal hernia was 24.8 % in those not undergoing the prophylactic procedure; 18.5 % in those undergoing the simple prophylactic procedure; and 0.00 % in those undergoing the processus vaginalis transection procedure (p < 0.001). In univariate and multivariate analysis, undergoing the processus vaginalis transection procedure and high body mass index were significant predictors for hernia-free survival after radical prostatectomy. CONCLUSION: Our data suggest that the processus vaginalis transection procedure is superior to the simple prophylactic procedure for the prevention of inguinal hernia after radical prostatectomy.