A Single Intradermal Injection of Autologous Adipose-Tissue-Derived Stem Cells Rejuvenates Aged Skin and Sharpens Double Eyelids.

Facial skin aging is the most visible manifestation of aging in the body. In this study, we aimed to rejuvenate aging skin via a one-time intradermal injection of autologous adipose-derived stem cells (ADSCs). Eight patients were enrolled for study. Photographs of patients taken immediately before and 1, 3, 6, and 12 months after ADSC injections were comparatively evaluated for visible skin manifestations. ADSCs were cultured from the abdominal-skin-derived subcutaneous fat tissue, and 1 × 108 cultured ADSCs were injected intradermally into the facial skin. Cultured myoblasts were incubated with the supernatant derived from ADSCs, and the effect was evaluated via glucose consumption and lactic acid production in the medium. Eight cases showed the shallowing and disappearance of wrinkles, including those of the glabella, lower eyelids, crow`s feet, and forehead and nasolabial grooves, a month to several months after treatment. Double eyelids became prominent, and facial pores significantly reduced in size. These effects lasted for over one year. Myoblasts cultured in the presence of an ADSC-derived exosome were activated compared to that of ADSCs cultured without supernatant. The result supports the role of muscle in ADSC skin rejuvenation. The present study first reports that a single intradermal administration of cultured ADSCs rejuvenates aged facial skin over the course of one year. Further, patients exhibited definite double eyelids and pore shrinkage, strongly indicating the active involvement of muscle, which was supported by an in vitro study. Our study also suggested the important role of biological factors delivered from injected stem cells, although the detailed mechanism of rejuvenation effects of ADSC skin injection remains to be clarified.

Increased anti-oxidative action compensates for collagen tissue degeneration in vitiligo dermis.

Vitiligo is a common depigmentation disorder characterized by the selective loss of melanocytes. In our daily clinic experience, we noticed that the skin tightness of hypopigmented lesions would be more evident in comparison to that of uninvolved perilesional skin in vitiligo patients. Therefore, we hypothesized that collagen homeostasis might be maintained in vitiligo lesions, irrespective of the substantial excessive oxidative stress that occurs in association with the disease. We found that the expression levels of collagen-related genes and anti-oxidative enzymes were upregulated in vitiligo-derived fibroblasts. Abundant collagenous fibers were observed in the papillary dermis of vitiligo lesions in comparison to uninvolved perilesional skin by electron microscopy. The production of matrix metalloproteinases that degraded collagen fibers was suppressed. The deposition of acrolein adduct protein, which is a product of oxidative stress, was significantly reduced in vitiligo dermis and fibroblasts. As part of the mechanism, we found upregulation of the NRF2 signaling pathway activity, which is an important defense system against oxidative stress. Taken together, we demonstrated that the anti-oxidative action and collagen production were upregulated and that the collagen degeneration was attenuated in vitiligo dermis. These new findings may provide important clues for the maintenance of antioxidant ability in vitiligo lesions.

Possible Involvement of Dermal Fibroblasts in Modulating Nrf2 Signaling in Epidermal Keratinocytes.

Epidermal keratinocytes protect themselves by cooperating with neighboring cells against internal and external stresses, which leads not only to the maintenance of cell homeostasis but also to the prevention of skin aging. Although it is known that nuclear factor (NF)-E2-related factor 2 (Nrf2) signaling plays a pivotal role in ameliorating oxidative stress and inflammatory responses under stress situations, it is unclear whether Nrf2 signaling in keratinocytes cooperates with neighboring cells such as dermal fibroblasts. Thus, this study was conducted to examine the influence of dermal fibroblasts on Nrf2 signaling in epidermal keratinocytes using a co-culture system. The results show that expression levels of Nrf2-regulated antioxidant factors, such as glutathione and heme oxygenase-1, in HaCaT keratinocytes (HaCaT KCs) are up-regulated in the presence of normal human dermal fibroblasts (NHDFs). In addition, the secretion of pro-inflammatory molecules, including interleukin-1α (IL-1α) and prostaglandin E2 (PGE2), is suppressed in co-cultures of NHDFs and UVB-irradiated HaCaT KCs. Interestingly, the localization of Nrf2 protein in HaCaT KCs was immediately translocated from the cytoplasm to the nucleus after the co-culture with NHDFs. These results suggest the possibility that Nrf2 signaling in keratinocytes is regulated in cooperation with dermal fibroblasts.

Pigmentation and TYRP1 expression are mediated by zinc through the early secretory pathway-resident ZNT proteins.

Tyrosinase (TYR) and tyrosinase-related proteins 1 and 2 (TYRP1 and TYRP2) are essential for pigmentation. They are generally classified as type-3 copper proteins, with binuclear copper active sites. Although there is experimental evidence for a copper cofactor in TYR, delivered via the copper transporter, ATP7A, the presence of copper in TYRP1 and TYRP2 has not been demonstrated. Here, we report that the expression and function of TYRP1 requires zinc, mediated by ZNT5-ZNT6 heterodimers (ZNT5-6) or ZNT7-ZNT7 homodimers (ZNT7). Loss of ZNT5-6 and ZNT7 function results in hypopigmentation in medaka fish and human melanoma cells, and is accompanied by immature melanosomes and reduced melanin content, as observed in TYRP1 dysfunction. The requirement of ZNT5-6 and ZNT7 for TYRP1 expression is conserved in human, mouse, and chicken orthologs. Our results provide novel insights into the pigmentation process and address questions regarding metalation in tyrosinase protein family.

[Case of Spindle Cell Carcinoma of the Breast Diagnosed as Mastitis].

The patient was a 51-year-old woman, who came to our hospital because of pain in her left breast and a tumor. US examination demonstrated a low echoic area with irregular margin and many high echoic spots within the left breast. We diagnosed mastitis. Therefore, we administered an antibiotic. One week later, her pain was improved. However, the low echoic area did not improve. Thus, we performed an aspiration cytology. Pus was aspirated. Cytology revealed a carcinoma. Enhanced CT demonstrated an irregular mass with ring enhancement in the left breast. A mastectomy with sentinel lymph- node biopsy and reconstruction with the latissimus dorsi muscle flap was performed. Post-operative course was uneventful. The pathological finding was of spindle cell carcinoma. After operation, she underwent chemotherapy(AC). Ten years later, she is alive with no recurrence.

Dermal Fibroblasts Internalize Phosphatidylserine-Exposed Secretory Melanosome Clusters and Apoptotic Melanocytes.

Pigmentation in the dermis is known to be caused by melanophages, defined as melanosome-laden macrophages. In this study, we show that dermal fibroblasts also have an ability to uptake melanosomes and apoptotic melanocytes. We have previously demonstrated that normal human melanocytes constantly secrete melanosome clusters from various sites of their dendrites. After adding secreted melanosome clusters collected from the culture medium of melanocytes, time-lapse imaging showed that fibroblasts actively attached to the secreted melanosome clusters and incorporated them. Annexin V staining revealed that phosphatidylserine (PtdSer), which is known as an 'eat-me' signal that triggers the internalization of apoptotic cells by macrophages, is exposed on the surface of secreted melanosome clusters. Dermal fibroblasts were able to uptake secreted melanosome clusters as did macrophages, and those fibroblasts express TIM4, a receptor for PtdSer-mediated endocytosis. Further, co-cultures of fibroblasts and melanocytes demonstrated that dermal fibroblasts internalize PtdSer-exposed apoptotic melanocytes. These results suggest that not only macrophages, but also dermal fibroblasts contribute to the collection of potentially toxic substances in the dermis, such as secreted melanosome clusters and apoptotic melanocytes, that have been occasionally observed to drop down into the dermis from the epidermis.

Riboflavin Plays a Pivotal Role in the UVA-Induced Cytotoxicity of Fibroblasts as a Key Molecule in the Production of H2O2 by UVA Radiation in Collaboration with Amino Acids and Vitamins.

To investigate environmental factors that contribute to ultraviolet A (UVA)-induced oxidative stress, which accelerates the senescence and toxicity of skin cells, we irradiated human fibroblasts cultured in commonly used essential media with UVA and evaluated their viability and production of reactive oxygen species. The viability of fibroblasts exposed to a single dose of 3.6 J/cm2 UVA was not reduced when cultured in Hanks balanced salt solution, but it was significantly decreased when cultured in Dulbecco's modified Eagle's medium (DMEM), which contains various amino acids and vitamins. Furthermore, cell viability was not reduced when fibroblasts were cultured in DMEM and treated with a hydrogen peroxide (H2O2) scavenger such as glutathione or catalase added after UVA irradiation. In addition, we confirmed that the production of H2O2 was dramatically increased by UVA photosensitization when riboflavin (R) coexisted with amino acids such as tryptophan (T), and found that R with folic acid (F) produced high levels of H2O2 after UVA irradiation. Furthermore, we noticed that R and F or R and T have different photosensitization mechanisms since NaN3, which is a singlet oxygen quencher, suppressed only R and T photosensitization. Lastly, we examined the effects of antioxidants (L-ascorbic acid, trolox, L-cysteine, and L-histidine), which are singlet oxygen or superoxide or H2O2 scavengers, on R and F or on R and T photosensitization, and found that 1 mM ascorbic acid, Trolox, and L-histidine were strongly photosensitized with R, and produced significant levels of H2O2 during UVA exposure. However, 1 mM L-cysteine dramatically suppressed H2O2 production by UVA photosensitization. These data suggest that a low concentration of R-derived photosensitization is elicited by different mechanisms depending on the coexisting vitamins and amino acids, and regulates cellular oxidative stress by producing H2O2 during UVA exposure.

TLR3 stimulation induces melanosome endo/phagocytosis through RHOA and CDC42 in human epidermal keratinocyte.

BACKGROUND: Keratinocytes and melanocytes in human epidermis express Toll-like receptors (TLR) and induce immune responses. We previously reported that TLR3 stimulation increases melanosome transport from perinuclear to cell membrane in melanocytes and enhanced release of melanosome from melanocytes, which were followed by increase in melanosome uptake into keratinocytes. OBJECTIVE: In this study, we investigated whether TLR3 stimuli directly affect keratinocytes to enhance melanosome uptake. METHODS: To observe keratinocyte's melanosome uptake ability precisely without melanocytes influences, we isolated melanosomes from human melanocytes and applied isolated melanosomes to keratinocytes stimulated by Poly(I:C). RESULTS: Poly(I:C)-stimulated keratinocytes enhanced uptake of isolated melanosome-rich globules five-times as much as control. Poly(I:C) increases the RNA and protein expressions of RHOA and CDC42, which are small GTP-binding proteins inducing the endocytosis. Pull-down assay showed that Poly(I:C) increased the GTP-binding RHOA and CDC42, suggesting TLR3 stimulation activated RHOA and CDC42. The knockdown of TLR3 suppressed RHOA and CDC42 induction by Poly(I:C). Consistently, the knockdown of RHOA and CDC42 significantly suppressed the melanosome-rich globules uptake by Poly(I:C)-stimulated keratinocytes. CONCLUSION: Because RHOA and CDC42 activation induces endocytosis by modification of actin stress fiber and filopodia formation, respectively, these results suggested that TLR3 stimulation enhances melanosome uptake into keratinocytes through endocytosis mechanisms. Combining with the data of our previous publications, TLR3, which signal is activated by sensing viral molecules, enhance pigmentation by controlling both melanin transport system by RAB GTPases induction in melanocytes and uptake system by RHOA and CDC42 in keratinocytes.

Placental extracts regulate melanin synthesis in normal human melanocytes with alterations of mitochondrial respiration.

Placental extracts have been widely used as skin lightening agents in the Japanese cosmetic market. Here, we show that placental extracts contain factors that can decrease or increase melanin synthesis by normal human melanocytes in vitro in possible association with mitochondrial respiration. When normal human melanocytes were treated with a whole porcine placental extract, melanin synthesis was decreased. In contrast, a porcine placental extract in which exudates and insoluble materials including lipids had been removed increased melanin synthesis. In addition, the amount of tyrosinase, the enzyme critical for melanin synthesis, changed in accordance with the alteration of melanin synthesis. Interestingly, the amount of manganese-dependent superoxide dismutase (MnSOD), a mitochondrial-resident antioxidant enzyme, was increased when melanin synthesis was decreased by the whole placental extract. Mitochondrial respiration and glycolysis also changed following treatment with the placental extracts. These results suggest that placental extracts contain factors that can increase or decrease melanin synthesis by normal human melanocytes and that mitochondrial function may be associated with the placental extract-induced regulation of melanogenesis.

Establishment of Photoaging In Vitro by Repetitive UVA Irradiation: Induction of Characteristic Markers of Senescence and its Prevention by PAPLAL with Potent Catalase Activity.

To understand a role of UVA radiation in photoaging of the skin, we established a model of photoaging cells using cultured human dermal fibroblasts. Repeated low-dose UVA radiation for 10 consecutive days induced senescence in fibroblasts, characterized with (1) increased level of senescence-associated ß-galactosidase, (2) flattened large cell shape, (3) accumulation of reactive oxygen species, (4) yellowish coloration and (5) expression of p16. These were also observed in chronologically aged fibroblasts (doubling times >20), whereas none of these were detected in young cells (doubling times <10). Collectively, we propose that fibroblasts exposed to repetitive UVA radiation may be a good model of aged cells to study the mechanism of aging and photoaging and further to search for novel agents preventing cellular senescence. In addition, H2 O2 was produced in the culture medium by a single low dose of UVA irradiation. Further, PAPLAL, a nanoparticle of platinum and palladium having potent catalase-like activity, significantly delayed the onset of H2 O2 -induced cell senescence. The present study strongly indicates that repetitive short-term UVA irradiation induces aging of cells possibly via H2 O2 and may be suppressed by potent anti-H2 O2 agents.

The maximal cumulative solar UVB dose allowed to maintain healthy and young skin and prevent premature photoaging.

The young facial skin of children with a smooth healthy appearance changes over time to photoaged skin having mottled pigmentation, solar lentigines, wrinkles, dry and rough skin, leathery texture, and benign and malignant tumors after exposure to chronic, repeated solar radiation. The first sign of photoaging in Japanese subjects is usually solar lentigines appearing around 20 years of age on the face. Fine wrinkles can then appear after 30 years of age, and benign skin tumors, seborrhoeic keratoses, can occur after 35 years of age in sun-exposed skin. We theoretically calculated the maximal daily exposure time to solar radiation, which could prevent the development of photoaged skin until 60 and 80 years of age, based on published data of personal solar UVB doses in sun-exposed skin. One MED (minimal erythema dose) was determined to be 20 mJ/cm(2) , and 200 MED was used as the average yearly dose of Japanese children. Further, we hypothesized that the annual dose of Japanese adults is the same as that of the children. The cumulative UVB dose at 20 years of age was thus calculated to be 4000 MED, and 22 MED was used as the maximal daily UVB dose based on data measured in Kobe, located in the central area of Japan. We used the solar UVB dose from 10:00 a.m. to 14:00 p.m. which occupies 60% of the total daily UV dose, to obtain the maximal UVB per hour in a day, and calculated the maximal daily UV exposure time that would delay the onset of solar lentigines until 60 or 80 years of age. The mean daily sun exposure time to maintain healthy skin until 80 years of age in the summer was calculated to be 2.54 min (0.14 MED) for unprotected skin and 127 min with the use of a sunscreen of SPF (sun protection factor) of 50. In this study, we did not evaluate the photoaging effect of UVA radiation, but findings of the adverse effects of UVA radiation on the skin have accumulated in the last decade. Therefore, it will be important to estimate the maximal dose of solar UV radiation to retard the onset of photoaging based on an evaluation of both solar UVB and UVA in the future. Finally, we expect that this study may contribute to keeping Japanese and other types of skin young and healthy by limiting the exposure of the skin to solar radiation outdoors during the day.

Melanosomes are transferred from melanocytes to keratinocytes through the processes of packaging, release, uptake, and dispersion.

Recent studies have described the role of shedding vesicles as physiological conveyers of intracellular components between neighboring cells. Here we report that melanosomes are one example of shedding vesicle cargo, but are processed by a previously unreported mechanism. Pigment globules were observed to be connected to the filopodia of melanocyte dendrites, which have previously been shown to be conduits for melanosomes. Pigment globules containing multiple melanosomes were released from various areas of the dendrites of normal human melanocytes derived from darkly pigmented skin. The globules were then captured by the microvilli of normal human keratinocytes, also derived from darkly pigmented skin, which incorporated them in a protease-activated receptor-2 (PAR-2)-dependent manner. After the pigment globules were ingested by the keratinocytes, the membrane that surrounded each melanosome cluster was gradually degraded, and the individual melanosomes then spread into the cytosol and were distributed primarily in the perinuclear area of each keratinocyte. These results suggest a melanosome transfer pathway wherein melanosomes are transferred from melanocytes to keratinocytes via the shedding vesicle system. This packaging system generates pigment globules containing multiple melanosomes in a unique manner.

Involvement of pigment globules containing multiple melanosomes in the transfer of melanosomes from melanocytes to keratinocytes.

The mechanism of melanosome transfer from melanocytes to keratinocytes has not been fully clarified. We now show a route of melanosome transfer using co-cultures of normal human melanocytes and keratinocytes. Substantial levels of melanosome transfer were elicited in co-cultures of melanocytes and keratinocytes separated by a microporous membrane filter. The melanocyte dendrites penetrated into the keratinocyte layer through the filter and many pigment globules were observed in keratinocytes. Electron microscopic observations revealed that melanosomes incorporated in keratinocytes were packed in clusters enclosed by a double membrane. Numerous pigment globules budded off from melanocyte dendrites and were released into the culture medium. Those pigment globules were filled with multiple melanosomes and a few mitochondria but no nuclei. When those globules were added to the culture medium of keratinocytes, they were incorporated and showed double membrane-enclosed melano-phagolysosomes consistent with the structures obtained from the co-culture system. In contrast, when individual naked melanosomes isolated from melanocytes were added to keratinocytes, they were also phagocytosed by keratinocytes but were enclosed by a single membrane in a manner distinct from the co-culture system. These results suggest a novel mechanism of melanosome transfer, wherein melanosomes are packed in membrane globules that bud off from melanocyte dendrites, where they are released into the extracellular space and then phagocytosed by keratinocytes.

1-(2,4-Dihydroxyphenyl)-3-(2,4-dimethoxy-3-methylpheny)propane inhibits melanin synthesis by dual mechanisms.

BACKGROUND: 1-(2,4-Dihydroxyphenyl)-3-(2,4-dimethoxy-3-methylpheny)propane (DP) was reported as a novel tyrosinase inhibitor by Nesterov et al. In previous study, we showed that DP is an antioxidant and accelerates the fading of UVB-induced tan in human skin but details of inhibiting mechanism of DP in melanogenesis remain incomplete. OBJECTIVE: To clarify additional mechanisms of DP inhibition of melanogenesis, we studied the effect of DP on tyrosinase processing and degradation. METHODS: Tyrosinase inhibition was assessed using mushroom and human tyrosinase. The effect of DP on mRNA and protein levels as well as glycosylation and degradation of tyrosinase was examined using normal human epidermal melanocytes (NHEM). RESULTS: DP was 200 times more potent than that of kojic acid in inhibiting mushroom tyrosinase activity. In contrast, DP (IC(50)=200µM) was significantly less effective at inhibiting tyrosinase from NHEM. DP decreased melanin content in cultured NHEM after 7th day (IC(50)=10µM). The IC(50) for DP against human tyrosinase activity was found to be at least 20 times higher than that of melanin synthesis. At a non-cytotoxic concentration DP did not decrease tyrosinase mRNA however protein level decreased by 46% after 48h treatment. DP did not alter the ratio of mature and immature tyrosinase assayed by endo H cleavage. Tyrosinase degradation assays revealed that DP accelerated tyrosinase degradation in NHEM. CONCLUSIONS: We found that DP acts through dual mechanisms to reduce melanin synthesis; by inhibition of tyrosinase activity via an anti-oxidant effect, and, more importantly, by the acceleration of tyrosinase degradation.

Quasi-drugs developed in Japan for the prevention or treatment of hyperpigmentary disorders.

Excess production of melanin or its abnormal distribution, or both, can cause irregular hyperpigmentation of the skin, leading to melasma and age spots. To date, various quasi-drugs that prevent or improve hyperpigmentary disorders have been developed and officially approved by the Ministry of Health, Labor and Welfare of Japan. Many of these inhibit the activity of tyrosinase, an enzyme required for melanin synthesis, for example, by competitive or non-competitive inhibition of its catalytic activity, by inhibiting its maturation, or by accelerating its degradation. In this review, we categorize the quasi-drugs developed in Japan to prevent or treat hyperpigmentary disorders, or both, and discuss perspectives for future development.

Beta-catenin regulates melanocyte dendricity through the modulation of PKCzeta and PKCdelta.

The Wnt/beta-catenin signaling pathway is involved in the melanocyte differentiation and melanoma development. However, the effect of beta-catenin for dendrite formation has not been clearly elucidated yet in normal human epidermal melanocytes (NHEM). To investigate the effect of beta-catenin, we transduced NHEM with recombinant adenovirus expressing beta-catenin. Forced expression of beta-catenin led to the dramatic morphological changes of NHEM, including the reduction of dendrite length and enlargement of cell body. Concomitantly with, the protein levels for dendrite formation-related molecules, such as Rac1 and Cdc42, were markedly decreased. In addition, phosphorylation of p38 MAPK was significantly reduced by beta-catenin, potentiating its inhibitory role for dendrite formation. Interestingly, overexpression of beta-catenin led to the increase of protein kinase C zeta (PKCzeta) level, while protein kinase C delta (PKCdelta) was decreased by beta-catenin, suggesting that those PKCs were beta-catenin-downstream modulators in NHMC. When PKCzeta was overexpressed, dendrites were shortened, with the reduced protein levels for Rac1 and Cdc42. In contrast, PKCdelta overexpression led to the elongation of dendrites, with the increased levels for Rac1 and Cdc42. These results suggest that beta-catenin play an inhibitory role for dendrite formation through the modulation of PKCzeta and PKCdelta.

Keratinocytes in culture accumulate phagocytosed melanosomes in the perinuclear area.

There are many techniques for evaluating melanosome transfer to keratinocytes but the spectrophotometric quantification of melanosomes incorporated by keratinocyte phagocytosis has not been previously reported. Here we describe a new method that allows the spectrophotometric visualization of melanosome uptake by normal human keratinocytes in culture. Fontana-Masson staining of keratinocytes incubated with isolated melanosomes showed the accumulation of incorporated melanosomes in the perinuclear areas of keratinocytes within 48 h. Electron microscopic observations of melanosomes ingested by keratinocytes revealed that many phagosomes containing clusters of melanosomes or their fragments were localized in the perinuclear area. A known inhibitor of keratinocyte phagocytosis which inhibits protease-activated receptor-2, i.e., soybean trypsin inhibitor, decreased melanosome uptake by keratinocytes in a dose-dependent manner. These data suggest that our method is a useful model to quantitate keratinocyte phagocytosis of melanosomes visually in vitro.

Role of the ubiquitin proteasome system in regulating skin pigmentation.

Pigmentation of the skin, hair and eyes is regulated by tyrosinase, the critical rate-limiting enzyme in melanin synthesis by melanocytes. Tyrosinase is degraded endogenously, at least in part, by the ubiquitin proteasome system (UPS). Several types of inherited hypopigmentary diseases, such as oculocutaneous albinism and Hermansky-Pudlak syndrome, involve the aberrant processing and/or trafficking of tyrosinase and its subsequent degradation which can occur due to the quality-control machinery. Studies on carbohydrate modifications have revealed that tyrosinase in the endoplasmic reticulum (ER) is proteolyzed via ER-associated protein degradation and that tyrosinase degradation can also occur following its complete maturation in the Golgi. Among intrinsic factors that regulate the UPS, fatty acids have been shown to modulate tyrosinase degradation in contrasting manners through increased or decreased amounts of ubiquitinated tyrosinase that leads to its accelerated or decelerated degradation by proteasomes.