The Effect of γ-Aminobutyric Acid Intake on UVB- Induced Skin Damage in Hairless Mice

The skin, the largest organ in the body, undergoes age-related changes influenced by both intrinsic and extrinsic factors. The primary external factor is photoaging which causes hyperpigmentation, uneven skin surface, deep wrinkles, and markedly enlarged capillaries. In the human dermis, it decreases fibroblast function, resulting in a lack of collagen structure and also decreases keratinocyte function, which compromises the strength of the protective barrier. In this study, we found that treatment with γ-aminobutyric acid (GABA) had no toxicity to skin fibroblasts and GABA enhanced their migration ability, which can accelerate skin wound healing. UVB radiation was found to significantly induce the production of matrix metalloproteinase 1 (MMP-1), but treatment with GABA resulted in the inhibition of MMP-1 production. We also investigated the enhancement of filaggrin and aquaporin 3 in keratinocytes after treatment with GABA, showing that GABA can effectively improve skin moisturization. In vivo experiments showed that oral administration of GABA significantly improved skin wrinkles and epidermal thickness. After the intake of GABA, there was a significant decrease observed in the increase of skin thickness measured by calipers and erythema. Additionally, the decrease in skin moisture and elasticity in hairless mice exposed to UVB radiation was also significantly restored. Overall, this study demonstrates the potential of GABA as functional food material for improving skin aging and moisturizing.

Inhibition of Melanosome Transport by Inducing Exon Skipping in Melanophilin

Exon skipping is an efficient technique to inhibit specific gene expression induced by a short-sequence peptide nucleic acid (PNA).To date, there has been no study on the effects of PNA on skin pigmentation. In melanocytes, the tripartite complex is responsible for the transport of mature melanosomes from the nucleus to the dendrites. The tripartite complex is composed of Rab27a, Mlph (Melanophilin), and Myosin Va. Defects in the protein Mlph, a melanosome transport-related protein, are known to cause hypopigmentation. Our study shows that Olipass peptide nucleic acid (OPNA), a cell membrane-permeable PNA, targets exon skipping in the Mlph SHD domain, which is involved in Rab27a binding. Our findings demonstrate that OPNA induced exon skipping in melan-a cells, resulting in shortened Mlph mRNA, reduced Mlph protein levels, and melanosome aggregation, as observed by microscopy. Therefore, OPNA inhibits the expression of Mlph by inducing exon skipping within the gene. These results suggest that OPNA, which targets Mlph, may be a potential new whitening agent to inhibit melanosome movement.

Oleanolic Acid Protects the Skin from Particulate Matter-Induced Aging

The role of particulate matter (PM) in health problems including cardiovascular diseases (CVD) and pneumonia is becoming increasingly clear. Polycyclic aromatic hydrocarbons, major components of PM, bind to aryl hydrocarbon receptor (AhRs) and promote the expression of CYP1A1 through the AhR pathway in keratinocytes. Activation of AhRs in skin cells is associated with cell differentiation in keratinocytes and inflammation, resulting in dermatological lesions. Oleanolic acid, a natural component of L. lucidum, also has anti-inflammation, anticancer, and antioxidant characteristics. Previously, we found that PM 10, induced the AhR signaling pathway and autophagy process in keratinocytes. Here, we investigated the effects of oleanolic acid on PM 10,-induced skin aging. We observed that oleanolic acid inhibits PM 10,-induced CYP1A1 and decreases the increase of tumor necrosis factor– alpha and interleukin 6 induced by PM 10,. A supernatant derived from keratinocytes cotreated with oleanolic acid and PM 10, inhibited the release of matrix metalloproteinase 1 in dermal fibroblasts. Also, the AhR-mediated autophagy disruption was recovered by oleanolic acid. Thus, oleanolic acid may be a potential treatment for addressing PM 10,-induced skin aging.

Particulate Matter-Induced Aryl Hydrocarbon Receptor Regulates Autophagy in Keratinocytes

Particulate matter (PM), which refers to the mixture of particles present in the air, can have harmful effects. Damage to cells by PM, including disruption of organelles and proteins, can trigger autophagy, and the relationship between autophagy and PM has been well studied. However, the cellular regulators of PM-induced autophagy have not been well characterized, especially in keratinocytes. The Aryl Hydrocarbon Receptor (AhR) is expressed in the epidermis and is activated by PM. In this study, we investigated the role of the AhR in PM-induced autophagy in HaCaT cells. Our results showed that PM led to AhR activation in keratinocytes. Activation of the AhR-target gene CYP1A1 by PM was reduced by co-treatment with α-naphthoflavone (α-NF), an AhR inhibitor. We also evaluated activation of the autophagy pathway in PM-treated keratinocytes. In HaCaT cells, treatment with PM treatment led to the induction of microtubules-associated proteins light chain 3 (LC3) and p62/SQSTM1, which are essential components of the autophagy pathway. To study the role of the AhR in mediating PM-induced autophagy, we treated cells with α-NF or used an siRNA against AhR. Expression of LC3-ІІ induced by PM was decreased in a dose dependent manner by α-NF. Furthermore, knockdown of AhR with siAhR diminished PM-induced expression of LC3-ІІ and p62. Together, these results suggest that inhibition of the AhR decreases PM-induced autophagy. We confirmed these results using the autophagy-inhibitors BAF and 3-MA. Taken together, our results indicate that exposure to PM induces autophagy via the AhR in HaCaT keratinocytes.

Oral Administration of Glycine and Leucine Dipeptides Improves Skin Hydration and Elasticity in UVB-Irradiated Hairless Mice

Placenta is a special organ that contains many nutrients such as growth factors, minerals, and bioactive peptides. Dipeptides of glycine and leucine are major components of porcine placenta extracts (PPE) that has been used as an alternative of human placenta extracts. In this study, we investigated whether major peptides of PPE, Glycyl-L-Leucine (Gly-Leu), L-Leucyl-Glycine (Leu-Gly), and L-Leucyl-L-Leucine (Leu-Leu), affect skin hydration and elasticity in vitro and in vivo. We found that Gly-Leu and Leu-Gly dipeptides induced the expression of transglutaminase 1 in normal human epidermal keratinocytes (NHEKs) whereas Leu-Leu dipeptides did not. Treatment with Gly-Leu or Leu-Gly significantly increased hyaluronan (HA) synthesis in NHEKs and the upregulation of hyaluronan synthase 2 (HAS2) mRNA level was confirmed. In addition, elastase activity was inhibited in NHEKs treated with Gly-Leu or Leu-Gly dipeptides. Oral administration of Gly-Leu or Leu-Gly dipeptides increased skin hydration and elasticity in UVB-irradiated hairless mice. The significant upregulation of HA in UVB-irradiated hairless mice was observed in response to oral administration of Gly-Leu or Leu-Gly. These results suggest that the major dipeptides of porcine placenta, Gly-Leu and Leu-Gly, are potentially active ingredients for skin moisturization formulations.

Skin Barrier Recovery by Protease-Activated Receptor-2 Antagonist Lobaric Acid

Atopic dermatitis (AD) results from gene and environment interactions that lead to a range of immunological abnormalities and breakdown of the skin barrier. Protease-activated receptor 2 (PAR2) belongs to a family of G-protein coupled receptors and is expressed in suprabasal layers of the epidermis. PAR2 is activated by both trypsin and a specific agonist peptide, SLIGKV-NH₂ and is involved in both epidermal permeability barrier homeostasis and epithelial inflammation. In this study, we investigated the effect of lobaric acid on inflammation, keratinocyte differentiation, and recovery of the skin barrier in hairless mice. Lobaric acid blocked trypsin-induced and SLIGKV-NH₂-induced PAR2 activation resulting in decreased mobilization of intracellular Ca²⁺ in HaCaT keratinocytes. Lobaric acid reduced expression of interleukin-8 induced by SLIGKV-NH₂ and thymus and activation regulated chemokine (TARC) induced by tumor necrosis factor-a (TNF-α) and IFN-γ in HaCaT keratinocytes. Lobaric acid also blocked SLIGKV-NH₂-induced activation of ERK, which is a downstream signal of PAR2 in normal human keratinocytes (NHEKs). Treatment with SLIGKV-NH₂ downregulated expression of involucrin, a differentiation marker protein in HaCaT keratinocytes, and upregulated expression of involucrin, transglutamase1 and filaggrin in NHEKs. However, lobaric acid antagonized the effect of SLIGKV-NH₂ in HaCaT keratinocytes and NHEKs. Topical application of lobaric acid accelerated barrier recovery kinetics in a SKH-1 hairless mouse model. These results suggested that lobaric acid is a PAR2 antagonist and could be a possible therapeutic agent for atopic dermatitis.

Hesperidin Suppresses Melanosome Transport by Blocking the Interaction of Rab27A-Melanophilin

We investigated the inhibitory effects of hesperidin on melanogenesis. To find melanosome transport inhibitor from natural products, we collected the structural information of natural products from Korea Food and Drug Administration (KFDA) and performed pharmacophore-based in silico screening for Rab27A and melanophilin (MLPH). Hesperidin did not inhibit melanin production in B16F10 murine melanoma cells stimulated with alpha-melanocyte stimulating hormone (alpha-MSH), and also did not affect the catalytic activity of tyrosinase. But, hesperidin inhibited melanosome transport in melanocyte and showed skin lightening effect in pigmented reconstructed epidermis model. Therefore, we suggest that hesperidin is a useful inhibitor of melanosome transport and it might be applied to whitening agent.

Distribution of Malassezia Species on the Scalp in Korean Seborrheic Dermatitis Patients

BACKGROUND: Malassezia species play an important role in the pathogenesis of seborrheic dermatitis. In particular, M. restricta and M. globosa are considered to be the predominant organisms in seborrheic dermatitis of Western countries. However, species distribution of Malassezia in seborrheic dermatitis has not been clearly determined yet in Asia. OBJECTIVE: To identify the distribution of Malassezia species on the scalp of seborrheic dermatitis patients in Korea using 26S rDNA PCR-RFLP analysis. METHODS: A total of 40 seborrheic dermatitis patients and 100 normal healthy volunteers were included in this study. For the identification of Malassezia species, the scalp scales of the subjects were analyzed by 26S rDNA PCR-RFLP analysis. RESULTS: The most commonly identified Malassezia species were M. restricta in the seborrheic dermatitis patients, and M. globosa in the normal controls. In the seborrheic dermatitis group, M. restricta was identified in 47.5%, M. globosa in 27.5%, M. furfur in 7.5%, and M. sympodialis in 2.5% of patients. In the healthy control group, M. globosa was identified in 32.0%, M. restricta in 25.0%, M. furfur in 8.0%, M. obtusa in 6.0%, M. slooffiae in 6.0%, and M. sympodialis in 4.0% of subjects. CONCLUSION: M. restricta is considered to be the most important Malassezia species in Korean seborrheic dermatitis patients.

A Study on the Antimicrobial Effect of Bamboo (Phyllosrachys bambusoides) Essential Oil on Malassezia / 대한의진균학회지

BACKGROUND: Malassezia is considered as major factor in dandruff of human scalp. OBJECTIVE: In order to develop an antimicrobial agent, bamboo oil was extracted by high temperture suction from dried bamboo truk abd then antimicrobial activities against Malassezia are investigated. METHODS: Minimum inhibitory concentration and antimicrobial activity were measured in Malassezia species. RESULTS: 1. Minimum inhibitory concentration of the Bamboo (Phyllosrachys bambusoides) Essential Oil Malassezia furfur standard, Malassezia furfur patient, Malassezia sympodialis standard, Malassezia sympodialis patient, Malassezia dermatis standard, Malassezia dermatis patient were 10 microliter/ml, 5 microliter/ml, 5 microliter/ml, 10 microliter/ml, 5 microliter/ml and 10 microliter/ml respectively. 2. Minimum inhibitory concentration of the Itraconazole Malassezia furfur standard, Malassezia furfur patient, Malassezia sympodialis standard, Malassezia sympodialis patient, Malassezia dermatis standardntia, Malassezia dermatis patient were 10 microgram/ml, 10 microgram/ml, 10 microgram/ml, 0.1 microgram/ml, 1 microgram/ml, and 0.01 microgram/ml, respectively. 3. Minimum inhibitory concentration of the ketoconazole Malassezia furfur standard, Malassezia furfur patient, Malassezia sympodialis standard, Malassezia sympodialis patient, Malassezia dermatis standard, Malassezia dermatis patient were 0.01 microgram/ml, 10 microgram/ml, 10 microgram/ml, 0.1 microgram/ml, 0.01 microgram/ml, and 0.01 microgram/ml, respectively. 4. Malassezia furfur standard, Malassezia furfur patient, Malassezia sympodialis patient and Malassezia dermatis patient showed the strongest antimicrobial effect on bamboo oil > ketoconazole > itraconazole. 5. Malassezia sympodialis standard, Malassezia sympodialis patient and Malassezia dermatis standard strongest antimicrobial effect on ketoconazole > bamboo oil > itraconazole. CONCLUSION: Bamboo oil might be applied as antidandruff treatment modality by its anti-malassezial effect.

Transcriptional profiling in human HaCaT keratinocytes in response to kaempferol and identification of potential transcription factors for regulating differential gene expression

Kaempferol is the major flavonol in green tea and exhibits many biomedically useful properties such as antioxidative, cytoprotective and anti-apoptotic activities. To elucidate its effects on the skin, we investigated the transcriptional profiles of kaempferol-treated HaCaT cells using cDNA microarray analysis and identified 147 transcripts that exhibited significant changes in expression. Of these, 18 were up-regulated and 129 were down-regulated. These transcripts were then classified into 12 categories according to their functional roles: cell adhesion/cytoskeleton, cell cycle, redox homeostasis, immune/defense responses, metabolism, protein biosynthesis/modification, intracellular transport, RNA processing, DNA modification/ replication, regulation of transcription, signal transduction and transport. We then analyzed the promoter sequences of differentially-regulated genes and identified over-represented regulatory sites and candidate transcription factors (TFs) for gene regulation by kaempferol. These included c-REL, SAP-1, Ahr-ARNT, Nrf-2, Elk-1, SPI-B, NF-kappaB and p65. In addition, we validated the microarray results and promoter analyses using conventional methods such as real-time PCR and ELISA-based transcription factor assay. Our microarray analysis has provided useful information for determining the genetic regulatory network affected by kaempferol, and this approach will be useful for elucidating gene-phytochemical interactions.

Radiologic Changes of Adjacent-level after Anterior Cervical Spinal Fusion: Midterm Follow-up Results / 대한척추외과학회지

STUDY DESIGN: We studied the changes of the adjacent-level after performing anterior cervical interbody fusion. OBJECTIVES: We retrospectively analyzed the radiologic changes such as the degenerative changes and osteophyte formation in the adjacent-level and the affecting factors that affect the changes of the adjacent level after anterior cervical interbody fusion. SUMMARY OF LITERATURE REVIEW: We studied the patients who were more than sixty years old and who had more degeneration at the time of operation and who developed symptomatic new disease within the first four years after their procedure. When the interbody spacer was shortened by 10% to simulate subsidence, the plate lost nearly 70% of its load-sharing capabilities. MATERIALS AND METHODS: All the patients were treated with a plate and an autoiliac bone graft. We reviewed the correlation between the changes in the adjacent level and the factors that included gender, age, the fused segments, the plate-to-disc distance, the preoperative degenerative changes in the adjacent level, subsidence of the graft bone, the height of the graft bone, fracture and dislocation, and loosening of the implant. RESULTS: Radiologic changes in the adjacent-level were seen in 35 cases and these cases included 27 cases in the upper level and 17 cases in lower level. Adjacent level changes were seen in 27 of the 37 (73%) patient who were above 50 years old. Adjacent level changes were seen in 19 (90.5%) of the 21 cases that had preoperative cephalad level degeneration, and adjacent level changes were seen in 9 (81.8%) of the 11 cases that had preoperative caudal degeneration. Adjacent level degeneration developed or increased in the cases of subsidence of a graft over 2 mm. CONCLUSIONS: The patients who undergo anterior cervical interbody fusion need to be continuously followed up because radiologic changes can increase in the case with degenerative change in the adjacent segment and subsidence of the bone graft of more than 2 mm.

Midterm Results of Treatment with a Retrograde Nail for Periprosthetic Fractures of the Femur Following Total Knee Arthroplasty

PURPOSE: To analyze the midterm results of the treatment with a retrograde nail for periprosthetic fractures of the femur following total knee arthroplasty. MATERIALS AND METHODS: Between Jan 1998 and Jan 2004, 11 cases in 11 patients were treated for the periprosthetic fractures following total knee arthroplasty. The mean follow-up was 42.0 (30~98) months and the mean age was 66.0 (57~79) years old. 2 were males and 9 patients were females. In all cases, retrograde nailing was done for the periprosthetic fractures. Postoperative range of motion, HSS knee rating score, femorotibial angle, the time required for union, complications were evaluated. RESULTS: Postoperative range of motion was 103.6° degrees on an average, HSS knee rating score was 83.5 points on an average at the last follow up. The mean angulation on radiograph was valgus 6.3°. The mean time required for union was 4 months. One had a newly fracture line at proximal part of supracondylar fracture, but there was no significant in clinical course. There was no prostheses required revision. CONCLUSION: It appears that retrograde nail is a reliable surgical technique for periprosthetic fractures of the femur following total knee arthroplasty with low complication rate. The midterm results in our study showed that none of the prostheses required revision.

Antipsychotics and Abnormality in Glucose Regulation

OBJECTIVE: The purpose of this study was to know about the mechanism of pathogenesis of type 2 diabetes mellitus by using of blood glucose, glucoregulatory factor, insulin resistance in schizophrenic patients receiving antipsychotics. METHOD: Modified oral glucose tolerance tests were performed in 20 schizophrenic patients receiving haloperidol, risperidone and olanzapine. Insulin, glucagon, C-peptide and cortisol were measured in 0, 15, 45, 75 minutes after glucose loading, and insulin resistance was calculated by HOMA(homeostasis model assessment) method. RESULT: Olanzapine-treated patients had significant glucose elevation 45 minutes after glucose challenge. Also modest increases in HOMA IR values were detected in patients treated with olanzapine. CONCLUSION: Olanzapine treatment of non-diabetic patients with schizophrenia can be associated with type 2 diabetes mellitus through the elevation of glucose and insulin resistance. Elevated insulin resistance may be a causative mechanism of type 2 diabetes mellitus in patients receiving olanzapine.