The effects of wearing a face mask and of subsequent moisturizer use on the characteristics of sensitive skin.

BACKGROUND: COVID-19 is a serious respiratory disease, and wearing masks has become essential in daily life. Nevertheless, the number of people complaining of skin problems caused by wearing masks is increasing. Therefore, we investigated the characteristics of changes in sensitive skin caused by wearing a mask. MATERIALS AND METHODS: Twenty healthy Korean women with sensitive skin participated in this study. To determine any skin-related changes caused by mask-wearing, we evaluated redness, hydration, transepidermal water loss (TEWL), and moisture at 2.5 mm below the surface before and 4 h after wearing a Korea Filter 94 mask. In addition, we tested whether applying a moisturizer for 30 min after mask removal could reverse any mask-induced changes. RESULTS: Skin redness and TEWL were significantly increased at 4 h after wearing a mask (p < 0.05), otherwise skin hydration and the 2.5 mm moisture were significantly decreased (p < 0.05). After applying the moisturizer, skin redness and TEWL were significantly decreased compared to their values 4 h after wearing masks (p < 0.05), whereas skin hydration and the 2.5 mm moisture were significantly increased (p < 0.05). Moreover, after applying the moisturizer, skin redness and TEWL were significantly reduced compared to the pre-masking baseline (p < 0.05), whereas skin hydration was significantly increased (p < 0.05); the 2.5 mm moisture showed no significant change. CONCLUSION: We observed that wearing masks causes physiological changes in sensitive skin, whereas applying a moisturizer after removing the mask improved skin conditions.

Folic acid is necessary for proliferation and differentiation of C2C12 myoblasts.

Folic acid, a water soluble B vitamin, plays an important role in cellular metabolic activities, such as functioning as a cofactor in one-carbon metabolism for DNA and RNA synthesis as well as nucleotide and amino acid biosynthesis in the body. A lack of dietary folic acid can lead to folic acid deficiency and result in several health problems, including macrocytic anemia, elevated plasma homocysteine, cardiovascular disease, birth defects, carcinogenesis, muscle weakness, and walking difficulty. However, the effect of folic acid deficiency on skeletal muscle development and its molecular mechanisms are unknown. We, therefore, investigated the effect of folic acid deficiency on myogenesis in skeletal muscle cells and found that folic acid deficiency induced proliferation inhibition and cell cycle breaking as well as cellular senescence in C2C12 myoblasts, implying that folic acid deficiency influences skeletal muscle development. Folic acid deficiency also inhibited differentiation of C2C12 myoblasts and induced deregulation of the cell cycle exit and many cell cycle regulatory genes. It inhibited expression of muscle-specific marker MyHC as well as myogenic regulatory factor (myogenin). Moreover, immunocytochemistry and Western blot analyses revealed that DNA damage was more increased in folic acid-deficient medium-treated differentiating C2C12 cells. Furthermore, we found that folic acid resupplementation reverses the effect on the cell cycle and senescence in folic acid-deficient C2C12 myoblasts but does not reverse the differentiation of C2C12 cells. Altogether, the study results suggest that folic acid is necessary for normal development of skeletal muscle cells.

Deficiency of Atg6 impairs beneficial effect of metformin on intestinal stem cell aging in Drosophila.

Age-related changes of adult stem cell are crucial for tissue aging and age-related diseases. Thus, clarifying mechanisms to prevent adult stem cell aging is indispensable for healthy aging. Metformin, a drug for type 2 diabetes, has been highlighted for its anti-aging and anti-cancer effect. In Drosophila intestinal stem cell (ISC), we previously reported the inhibitory effect of metformin on age-related phenotypes of ISC. Here, we showed that knockdown of Atg6, a crucial autophagy-related factor, in ISC induces age-related phenotypes of ISC such as hyperproliferation, centrosome amplification, and DNA damage accumulation. Then, we revealed that metformin inhibits ISC aging phenotypes in Atg6-dependent manner. Taken together, our study suggests that Atg6 is required for the inhibitory effect of metformin on ISC aging, providing an intervention mechanism of metformin on adult stem cell aging.

Age-related change in γH2AX of Drosophila muscle: its significance as a marker for muscle damage and longevity.

Muscle aging is closely related to unhealthy late-life and organismal aging. Recently, the state of differentiated cells was shown to be critical to tissue homeostasis. Thus, understanding how fully differentiated muscle cells age is required for ensuring healthy aging. Adult Drosophila muscle is a useful model for exploring the aging process of fully differentiated cells. In this study, we investigated age-related changes of γH2AX, an indicator of DNA strand breaks, in adult Drosophila muscle to document whether its changes are correlated with muscle degeneration and lifespan. The results demonstrate that γH2AX accumulation increases in adult Drosophila thoracic and leg muscles with age. Analyses of short-, normal-, and long-lived strains indicate that the age-related increase of γH2AX is closely associated with the extent of muscle degeneration, cleaved caspase-3 and poly-ubiquitin aggregates, and longevity. Further analysis of muscle-specific knockdown of heterochromatin protein 1a revealed that the excessive γH2AX accumulation in thoracic and leg muscles induces accelerated degeneration and decreases longevity. These data suggest a strong correlation between age-related muscle damage and lifespan in Drosophila. Our findings indicate that γH2AX may be a reliable biomarker for assessing muscle aging in Drosophila.

Increased centrosome amplification in aged stem cells of the Drosophila midgut.

Age-related changes in long-lived tissue-resident stem cells may be tightly linked to aging and age-related diseases such as cancer. Centrosomes play key roles in cell proliferation, differentiation and migration. Supernumerary centrosomes are known to be an early event in tumorigenesis and senescence. However, the age-related changes of centrosome duplication in tissue-resident stem cells in vivo remain unknown. Here, using anti-γ-tubulin and anti-PH3, we analyzed mitotic intestinal stem cells with supernumerary centrosomes in the adult Drosophila midgut, which may be a versatile model system for stem cell biology. The results showed increased centrosome amplification in intestinal stem cells of aged and oxidatively stressed Drosophila midguts. Increased centrosome amplification was detected by overexpression of PVR, EGFR, and AKT in intestinal stem cells/enteroblasts, known to mimic age-related changes including hyperproliferation of intestinal stem cells and hyperplasia in the midgut. Our data show the first direct evidence for the age-related increase of centrosome amplification in intestinal stem cells and suggest that the Drosophila midgut is an excellent model for studying molecular mechanisms underlying centrosome amplification in aging adult stem cells in vivo.

A validation study to find highly correlated parameters with visual assessment for clinical evaluation of cosmetic anti-cellulite products.

BACKGROUND/PURPOSE: There has been growing interest in cellulite on parts of the body; however, no objective assessment has been specifically established. This study aims to demonstrate an optimized method by comparing the existing assessments of cellulite. METHODS: In Test 1, for subjects of 20 healthy females who have cellulite, we measured volume and roughness of cellulite using fringe projection method, roughness using replica method, dermo-subcutaneous interface length and subcutaneous thickness using ultrasonography and skin temperature using infrared ray, elasticity and blood flow. In Test 2, we applied an anti-cellulite cosmetic to 28 subjects for 6 weeks and observed if they have any changes. RESULTS: In Test 1, the effective parameter that is the most correlated with visual assessment was volume of skin measured using fringe projection method (r = 0.780). Dermo-subcutaneous interface length (r = 0.355) and subcutaneous thickness (r = 0.502) measured using ultrasonography followed in order. In Test 2, after applying a tested product, the correlation coefficient of volume of skin, of dermo-subcutaneous interface length and of subcutaneous thickness are 0.409 (P = 0.000), 0.275 (P = 0.016) and 0.311 (P = 0.012) respectively. CONCLUSION: We conclude that visual assessment, volume of skin (cavities), dermo-subcutaneous interface length and subcutaneous thickness are optimized methods for assessing an effect of cosmetics on cellulite.

Histone demethylase JMJD2B-mediated cell proliferation regulated by hypoxia and radiation in gastric cancer cell.

Histone modifying factors are functional components of chromatin and play a role in gene regulation. The expression level of JMJD2B, a histone demethylase, is notably up-regulated in cancer tissues. Upregulation of JMJD2B promotes cancer cell proliferation under hypoxic conditions through target gene expression. Here, we describe the patterns of histone methylation and JMJD2B expression under various stressed conditions, such as hypoxia and radiation, in a gastric cancer cell line. JMJD2B expression in AGS cells was actively regulated by hypoxia and radiation. Chromatin immunoprecipitation experiments demonstrated that binding of JMJD2B on the cyclin A1 (CCNA1) promoter resulted in CCNA1 upregulation under hypoxic conditions. Furthermore, we confirmed that AGS cell proliferation was directly affected by JMJD2B and CCNA1 expression by performing experiments with JMJD2B depleted cells. Interestingly, the effects of JMJD2B on cell growth under hypoxia were remarkably repressed after gamma-ray irradiation. These results suggest that JMJD2B may play a central role in gastric cancer cell growth and might constitute a novel therapeutic target to overcome hypoxia-induced radio-resistance, thereby improving the efficiency of radiation therapy.

Requirement of matrix metalloproteinase-1 for intestinal homeostasis in the adult Drosophila midgut.

Stem cells are tightly regulated by both intrinsic and extrinsic signals as well as the extracellular matrix (ECM) for tissue homeostasis and regenerative capacity. Matrix metalloproteinases (MMPs), proteolytic enzymes, modulate the turnover of numerous substrates, including cytokine precursors, growth factors, and ECM molecules. However, the roles of MMPs in the regulation of adult stem cells are poorly understood. In the present study, we utilize the Drosophila midgut, which is an excellent model system for studying stem cell biology, to show that Mmp1 is involved in the regulation of intestinal stem cells (ISCs). The results showed that Mmp1 is expressed in the adult midgut and that its expression increases with age and with exposure to oxidative stress. Mmp1 knockdown or Timp-overexpressing flies and flies heterozygous for a viable, hypomorphic Mmp1 allele increased ISC proliferation in the gut, as shown by staining with an anti-phospho-histone H3 antibody and BrdU incorporation assays. Reduced Mmp1 levels induced intestinal hyperplasia, and the Mmp1depletion-induced ISC proliferation was rescued by the suppression of the EGFR signaling pathway, suggesting that Mmp1 regulates ISC proliferation through the EGFR signaling pathway. Furthermore, adult gut-specific knockdown and whole-animal heterozygotes of Mmp1 increased additively sensitivity to paraquat-induced oxidative stress and shortened lifespan. Our data suggest that Drosophila Mmp1 is involved in the regulation of ISC proliferation for maintenance of gut homeostasis.

Analysis of the temporal change in biophysical parameters after fractional laser treatments using reflectance confocal microscopy.

BACKGROUND: Fractional photothermolysis is a popular treatment option for photorejuvenation. Previous literature studies have demonstrated the clinical effectiveness of fractional photothermolysis on cutaneous photoaging; however, the associated changes in biophysical properties of the skin following fractional photothermolysis have not been fully elucidated. This study was conducted to investigate the temporal changes in biophysical parameters after fractional laser treatment on Asian skin. MATERIALS AND METHODS: Eleven female subjects underwent a single treatment with an erbium glass fractional laser. Skin roughness, elasticity, transepidermal water loss (TEWL), dermal thickness were evaluated before and immediately after treatment and 3 days, 1 week, 2 weeks, and 4 weeks after treatment. The changes in the dermal papilla were analyzed using a reflectance confocal microscopy (RCM). RESULTS: Skin roughness showed the greatest improvement at the first week and net elasticity was most improved at the second week. TEWL and the percentage of melanized and active dermal papillae (DP) were mostly increased for 3 days. At 4 weeks after treatment, the number of total dermal papillae showed a significant increase compared with pretreatment. CONCLUSION: This is the first study of the characterization and quantification of dermal papilla reflecting the dermal repair process after fractional photothermolysis through an RCM.

Caudal-related homeodomain proteins CDX1/2 bind to DNA replication-related element binding factor.

In the intestinal epithelium, the CDX1 and CDX2 homeodomain genes play proliferative and tumor suppressor roles, respectively. The transcription factor DNA replication-related element binding factor (DREF), is an 80kDa polypeptide homodimer that plays an important role in regulating cell proliferation-related genes. Homeodomain genes encode DNA-binding proteins that play crucial roles during development by defining the body plan and determining cell fate. However, until now, the regulation of DREF function by caudal-related homeodomain proteins is poorly understood. In this study, recombinant CDX1/2 homeodomains (CDX1, amino acids [aa] 152-216 and CDX2, aa 184-248) and the DNA-binding domain of Drosophila DREF (dDREF; aa 1-125) were isolated in order to investigate the regulatory mechanism of their interaction. The expression and purification of the truncated CDX1/2 and DREF proteins were successfully performed in Escherichia coli. Models of the CDX1/2 homeodomain and dDREF were constructed using SWISS-MODEL software, a program for relative protein structure modeling. The binding of CDX1/2 and DREF proteins was detected by fluorescence measurement, size-exclusion column (SEC) chromatography, His-tagged pull-down assay, and surface plasmon resonance spectroscopy (BIAcore). In addition, we identified that four different mutants of CDX1 (S185A, N190A, T194A, and V212A) were bound to dDREF with different degrees of interaction. Our results indicate that CDX1/2 homeodomains interact with the DNA-binding domain of dDREF, thereby regulating its transcription activity.

Regulation of intestinal stem cell proliferation by human methyl-CpG-binding protein-2 in Drosophila.

Recent studies have suggested the involvement of epigenetic factors such as methyl-CpG-binding protein-2 (MeCP2) in tumorigenesis. In addition, cancer may represent a stem cell-based disease, suggesting that understanding of stem cell regulation could provide valuable insights into the mechanisms of tumorigenesis. However, the function of epigenetic factors in stem cell regulation in adult tissues remains poorly understood. In the present study, we investigated the role of human MeCP2 (hMeCP2), a bridge factor linked to DNA modification and histone modification, in stem cell proliferation using adult Drosophila midgut, which appears to be an excellent model system to study stem cell biology. Results show that enterocyte (EC)-specific expression of hMeCP2 in adult midgut using an exogenous GAL4/UAS expression system induced intestinal stem cell (ISC) proliferation marked by staining with anti-phospho-histone H3 antibody and BrdU incorporation assays. In addition, hMeCP2 expression in ECs activated extracellular stress-response kinase signals in ISCs. Furthermore, expression of hMeCP2 modulated the distribution of heterochromatin protein-1 in ECs. Our data suggests the hypothesis that the expression of hMeCP2 in differentiated ECs stimulates ISC proliferation, implying a role of MeCP2 as a stem cell regulator.

Regulation of the Drosophila p38b gene by transcription factor DREF in the adult midgut.

The Drosophila midgut is an excellent model for evaluation of gene networks that regulate adult stem cell proliferation and differentiation. The Drosophila p38b (D-p38b) gene has been shown to be involved in intestinal stem cell (ISC) proliferation and differentiation in the adult midgut. Here, we report that D-p38b gene expression is regulated by DREF (DNA replication-related element binding factor) in the adult midgut. We have identified a DRE in the 5'-flanking region of the D-p38b gene and showed that DREF could bind to this DRE via a gel mobility shift assay and a ChIP assay. Base-substitution mutations of the D-p38b promoter DRE and analyses of transformants carrying D-p38b-lacZ or D-p38b-DREmut-lacZ indicated that this DRE is required for the activity of the D-p38b gene promoter. Furthermore, by using the GAL4-UAS system, we showed that DREF regulates the activity of the D-p38b gene promoter in adult ISCs and progenitors. In addition, the D-p38b knockdown phenotypes in the midgut were rescued by DREF overexpression, suggesting a functional link between these two factors. Our results suggest that the D-p38b gene is regulated by the DREF pathway and that DREF is involved in the regulation of proliferation and differentiation of Drosophila ISCs and progenitors.

Thromboxane A(2) increases endothelial permeability through upregulation of interleukin-8.

Thromboxane A(2) (TXA(2)), a major prostanoid formed from prostaglandin H(2) by thromboxane synthase, is involved in the pathogenesis of a variety of vascular diseases. In this study, we report that TXA(2) mimetic U46619 significantly increases the endothelial permeability both in vitro and in vivo. U46619 enhanced the expression and secretion of interleukin-8 (IL-8), a major inducer of vascular permeability, in endothelial cells. Promoter analysis showed that the U46619-induced expression of IL-8 was mainly regulated by nuclear factor-kappaB (NF-kappaB). U46619 induced the activation of NF-kappaB through IkappaB kinase (IKK) activation, IkappaB phosphorylation and NF-kappaB nuclear translocation. Furthermore, the inhibition of IL-8 or blockade of the IL-8 receptor attenuated the U46619-induced endothelial cell permeability by modulating the cell-cell junctions. Overall, these results suggest that U46619 promotes vascular permeability through the production of IL-8 via NF-kappaB activation in endothelial cells.

Molecular activation of NF-kappaB, pro-inflammatory mediators, and signal pathways in gamma-irradiated mice.

The effects of gamma-irradiation on inflammatory gene expression, including NF-kappaB activation, in the kidney of C57/BL6 mice exposed to 1-9 Gy doses of (60)Co gamma-irradiation. Radiation enhanced the NF-kappaB activation and oxidative stress caused a dose-dependent disruption in the redox balance. The significance of this study is the new molecular information gained on gamma-irradiation effects through the activation of pro-inflammatory genes by NF-kappaB via the MAPK signaling pathway. Considering the exquisite sensitivity of NF-kappaB and other pro-inflammatory mediators to the redox status, we conclude that the activation of inflammatory processes by irradiation is likely initiated by increased oxidative stress.

The DRE/DREF transcriptional regulatory system: a master key for cell proliferation.

The coordinate expression of many cell proliferation-related genes is required for the cellular shift from the resting state into the proliferating state. One regulatory factor involved in this process, the transcription regulatory factor named DREF (DNA replication-related element-binding factor) was discovered in Drosophila and later found to have orthologues in other species including human. Drosophila DREF is a homo-dimer of a polypeptide of 709 amino acid residues, and shares about 22% identity in its amino acid sequence with the human homolog of 694 amino acid residues. The Drosophila DREF homo-dimer binds specifically to the DRE sequence (5'-TATCGATA) in the promoters of many DNA replication/ cell proliferation-related genes to activate their transcription, and the N-terminal region of DREF carries a domain for specific DRE-binding and homo-dimer formation. Ectopic expression of DREF in eye imaginal discs induces abnormal DNA synthesis, apoptosis and failure to differentiate. Conversely, expression of the dominant negative N-terminal region in larval salivary glands reduces endo-replication. Furthermore, RNA interference-mediated knockdown of DREF in vivo demonstrated its requirement for normal progression through the cell cycle and consequently for growth of imaginal discs and the endoreplicating organs. Both Drosophila and human DREF's interact genetically and physically with regulatory factors related to chromatin structures, suggesting that DREF activates the expression of proliferation-related genes through modification of the 3-D conformation of DNA. A search of the Drosophila genome database identified about 150 genes carrying DRE sequences in their promoter regions, many of which are related to reactions required for cell proliferation such as DNA replication, transcriptional regulation, cell cycle regulation, growth signal transduction and protein metabolism. Thus, DREF appears to be a master key-like factor for cell proliferation. Several differentiation-related transcription factors containing homeodomains down-regulate the function or expression of DREF by distinct mechanisms, suggesting a differentiation-coupled repression of cell proliferation via the DRE/DREF system.

Age-related upregulation of Drosophila caudal gene via NF-kappaB in the adult posterior midgut.

The Drosophila midgut has emerged as a powerful model system for the investigation of fundamental cellular pathways relevant to intestinal stem cell biology. Understanding the age-related changes in the adult Drosophila midgut may provide insights into the molecular mechanisms that link aging to the modulation of adult stem cell population. The caudal-related homeobox genes encode intestine-specific transcription factors required for normal intestinal development and maintenance. Here, we demonstrate that caudal gene expression is upregulated in the adult posterior midgut in response to age and oxidative stress, and that overexpression of Caudal can stimulate cell proliferation in the adult posterior midgut. We further demonstrate that the age- and oxidative-stress-related upregulation of the caudal gene is mediated by the NF-kappaB binding site located in the 5'-flanking region of the caudal gene. Our results may contribute to an understanding of the mechanisms of age-related changes in the number and activity of intestinal stem cells and progenitors in the Drosophila adult midgut.

Big brain, a Drosophila homologue of mammalian aquaporin, is regulated by the DRE/DREF system.

Drosophila big brain (bib) encodes for a protein similar to members of the major intrinsic protein family, which includes the water- and ion-conducting aquaporin (AQP) channels. In mammals, AQP dysregulation has been implicated in a variety of diseases, including colorectal cancer and colonic injury. However, the regulatory mechanisms of AQP expression remain to be clearly elucidated. In this study, as we found a DREF binding site (DRE) in the 5'-flanking regions of both the Drosophila bib gene and the human AQP1 gene, we assessed the role of DREF in bib gene expression. DREF in Drosophila and humans has been demonstrated to function as a key transcriptional activator for cell proliferation-related genes. Herein, we demonstrate that the DRE is required for optimal promoter activity of Drosophila bib gene, particularly in the larval imaginal discs, which are actively proliferating tissues, as well as the adult hindgut. Our results may provide insight into the mechanisms inherent to the regulation of mammalian AQP genes.

Visfatin enhances ICAM-1 and VCAM-1 expression through ROS-dependent NF-kappaB activation in endothelial cells.

Visfatin has recently been identified as a novel visceral adipokine which may be involved in obesity-related vascular disorders. However, it is not known whether visfatin directly contributes to endothelial dysfunction. Here, we investigated the effect of visfatin on vascular inflammation, a key step in a variety of vascular diseases. Visfatin induced leukocyte adhesion to endothelial cells and the aortic endothelium by induction of the cell adhesion molecules, ICAM-1 and VCAM-1. Promoter analysis revealed that visfatin-mediated induction of CAMs is mainly regulated by nuclear factor-kappaB (NF-kappaB). Visfatin stimulated IkappaBalpha phosphorylation, nuclear translocation of the p65 subunit of NF-kappaB, and NF-kappaB DNA binding activity in HMECs. Furthermore, visfatin increased ROS generation, and visfatin-induced CAMs expression and NF-kappaB activation were abrogated in the presence of the direct scavenger of ROS. Taken together, our results demonstrate that visfatin is a vascular inflammatory molecule that increases expression of the inflammatory CAMs, ICAM-1 and VCAM-1, through ROS-dependent NF-kappaB activation in endothelial cells.

Purification of caudal-related homeodomain transcription factor and its binding characterization.

Human CDX2 is known as a caudal-related homeodomain transcription factor that is expressed in the intestinal epithelium and is important in differentiation and maintenance of the intestinal epithelial cells. The caudal-related homeobox proteins bind DNA according to a helix-turn-helix structure, thereby increasing the structural stability of DNA. A cancer-tumor suppressor role for Cdx2 has been shown by a decrease in the level of the expression of Cdx2 in colorectal cancer but the mechanism of transcriptional regulation has not been examined at the molecular level. We developed a large-scale system for expression of the recombinant, novel CDX2, in the Escherichia coli. A highly purified and soluble CDX2 protein was obtained in E. coli strain BL21(DE3)RIL and a hexahistidine fusion system using Ni-NTA affinity column, anion exchange, and gel filtration chromatography. The identity and secondary structure of the purified CDX2 protein were confirmed by MALDI-TOF MS, Western blot, and a circular dichroism analyses. In addition, we studied the DNA binding activity of recombinant CDX2 by ELISA experiment and isolated human CDX2 binding proteins derived from rat cells by an immobilized GST-fusion method. Three CDX2-binding proteins were found in the gastric tissue, and those proteins were identified to the homeobox protein Hox-D8, LIM homeobox protein 6, and SMC1L1 protein.

Transcriptional regulation of the Drosophila caudal homeobox gene by bHLH-PAS proteins.

Caudal-related homeobox transcription factors are involved in the definition of the anteroposterior axis and intestinal development. Recent reports indicate that dysregulation of CDX1 and CDX2, the human homologues of Drosophila caudal, are associated with several types of cancer. Very little is known, however, about the regulatory mechanisms that direct the caudal-related homeobox gene expression. In this study, we have identified the binding sites for bHLH-PAS proteins, referred to as CNS midline element (CME), in the 5'-flanking region of the Drosophila caudal gene. Analyses using transgenic flies carrying a caudal-lacZ fusion gene bearing a wild-type or mutant CME indicate that the CME sites are required for caudal gene expression in vivo. We also determined that the caudal promoter activity can be regulated by Trachealess (Trh)/Tango (Tgo) bHLH-PAS proteins, via the CME sites. Our results suggest that the Drosophila caudal gene is a target of the Trh/Tgo bHLH-PAS proteins.