Kozo Nakai

Sphingosine 1-phosphate attenuates H2O2-induced apoptosis in endothelial cells.

Reactive oxygen species including H(2)O(2) lead vascular endothelial cells (EC) to undergo apoptosis. Sphingosine 1-phosphate (S1P) is a platelet-derived sphingolipid mediator that elicits various EC responses. We aimed to explore whether and how S1P modulates EC apoptosis induced by H(2)O(2). Treatment of cultured bovine aortic EC (BAEC) with H(2)O(2) (750 microM for 6h) led to DNA fragmentation (ELISA), DNA nick formation (TUNEL staining), and cleavage of caspase-3, key features of EC apoptosis. These responses elicited by H(2)O(2) were alike markedly attenuated by pretreatment with S1P (1 microM, 30 min). H(2)O(2) induced robust phosphorylation of both p38 and JNK MAP kinases. However, pretreatment with S1P decreased phosphorylation of only p38 MAP kinase, but not that of JNK; conversely, an inhibitor of p38 MAP kinase, but not that of JNK, attenuated H(2)O(2)-induced caspase-3 activation. Thus S1P attenuates H(2)O(2)-induced apoptosis of cultured BAEC, involving p38 MAP kinase.

Reduced Expression of Epidermal Growth Factor Receptor, E-Cadherin, and Occludin in the Skin of Flaky Tail Mice Is Due to Filaggrin and Loricrin Deficiencies

Disruption of skin barrier function leads to increases in the percutaneous transfer of allergens and the incidence of atopic dermatitis. Flaky tail (Flg(ft)) mice have been used as a model of atopic dermatitis with skin barrier dysfunction. Although Flg(ft) mice are known to have filaggrin mutation, the mechanism responsible for the skin barrier dysfunction that they display needs to be determined, especially for the roles of epidermal adhesion and junction proteins. Herein, we report the decreased expression of epidermal growth factor receptor (EGFR), E-cadherin, occludin, and SIRT1 in the skin of Flg(ft) mice, compared with those in C57BL/6J mice. Administration of N-acetyl-L-cysteine, an antioxidant, in the drinking water improved these protein expressions in the skin of Flg(ft) mice. Notably, we discovered that loricrin expression was suppressed in Flg(ft) mice. In vitro experiments showed that filaggrin small interfering RNA, loricrin small interfering RNA, or SIRT1 inhibitor sirtinol suppressed the expression levels of EGFR, E-cadherin, and occludin in a human immortalized keratinocyte cell line (HaCaT cells). Our findings suggest that the observed reductions in EGFR, E-cadherin, and occludin expression were due to filaggrin deficiency accompanied with subsequent loricrin deficiency and disruption of the SIRT1 pathway in the skin of Flg(ft) mice.

Community-based epidemiological study of psychosocial effects of acne in Japanese adolescents

In this community‐based cross‐sectional study, 1443 Japanese adolescents aged 13–19 years participated from two schools in Kagawa Prefecture. Students completed a self‐administered questionnaire to assess the prevalence of acne, knowledge about acne, self‐management of acne and emotional well‐being. A five‐item version of the Mental Health Inventory (MHI) subscale of the Short Form 36 was used to assess psychological health and depression status. Among respondents, 859 (59.5%) said they had acne (51.6% of the boys and 64.8% of the girls). A majority (56.8%) of those who said they had acne also reported a family history of acne. Of the 555 female respondents with acne, 39.1% reported experiencing acne flares in temporal proximity to menstruation. Less than half (38.8%) of respondents with acne had sought or were seeking treatment. The three most common factors believed to trigger or exacerbate acne were stress, lack of sleep and sweat. The mean MHI score of 847 students with acne was significantly lower than 475 students without acne. The mean MHI score of female students with acne was significantly lower than male students with acne. Students with acne were also significantly more depressed than those without acne and female students were significantly more depressed than male students. Acne is a common problem for Japanese teenagers and causes personal and social difficulties. Our results suggest the necessity of educational programs in school or public to ensure that adolescents are aware of acne and to encourage young people to improve their mental health through better acne treatment.

HB-EGF-induced VEGF production and eNOS activation depend on both PI3 kinase and MAP kinase in HaCaT cells

BACKGROUND Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of growth factors that have been implicated in skin patho-physiology. Although endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) appear to be involved in mitogenesis and chemotaxis in epidermal keratinocytes, the activation of eNOS and VEGF production induced by HB-EGF and its signaling mechanism remains undefined. OBJECTIVE We examined possible signal transduction pathways by which HB-EGF leads to eNOS activation and VEGF production in human epidermal keratinocyte cell line (HaCaT cells). METHODS The phosphorylation of epidermal growth factor receptor (EGFR), mitogen-activated protein kinase (MAPK; p42/p44 MAPK), Akt and eNOS were examined by Western blotting analysis. VEGF production was determined by enzyme-linked immunosorbent assay. Various inhibitors were utilized to investigate the signaling mechanisms of eNOS activation and VEGF production. RESULTS HB-EGF-induced phosphorylation of EGFR with maximum phosphorylation at 1h. HB-EGF-induced phosphorylation of p42/p44 MAPK in a few minutes. It activated Akt with maximum phosphorylation at 1h and eNOS with maximum phosphorylation at 3h. The HB-EGF-induced eNOS activation was significantly blocked by the p42/p44 MAPK inhibitor U0126 and the phosphatidylinositol 3-kinase (P13K) inhibitor LY294002. HB-EGF increased VEGF production. The HB-EGF-induced VEGF production was blocked by U0126 and LY294002. Finally, the HB-EGF-induced activation of Akt and eNOS was suppressed by VEGF competitive antagonist, CBO-P11. CONCLUSION These results demonstrate that HB-EGF-induced eNOS activation depends on p42/p44 MAPK, PI3K/Akt pathways and endogenous VEGF in HaCaT cells.

Urinary biomarker of oxidative stress in patients with psoriasis vulgaris and atopic dermatitis

Background  The involvement of oxidative stress in the pathogenesis of various skin disorders has been suggested for decades. However, few clinical studies have assessed oxidative stress in skin diseases. The easiest and least invasive method to assess oxidative stress in patients may be the measurement of oxidation products in urine.

A Simple Therapeutic Strategy with Super Elastic Wire for Ingrown Toenails

An ingrown toenail, which causes pain especially with secondary infection, is one of the most common diseases of toenails. It becomes difficult for a patient to walk and subsequently impairs quality of life. Surgical procedures, including total or partial excision of the nailbed, phenolization, and carbon dioxide laser matricectomy method, are commonly performed. The disadvantages of these methods include complexity, pain, time consumption, and the need for local anesthesia during the operation. Moreover, these methods may cause a cosmetic deformity, resulting in narrower nail width, and recurrence occurs in approximately 1% to 4% of patients who receive phenolization. Physicians in clinics usually use cotton, elastic tape, polyacryl sculptured nails, or flexible tube splinting as nonsurgical procedures, but cotton insertion and elastic taping require frequent home care for maintenance, and flexible tube splinting requires local anesthesia. Some devices, such as a VHO-Osthold brace or a plastic device, have been recently designed with favorable results, although the effectiveness of these regimens awaits future evaluation.

Ascorbate enhances iNOS activity by increasing tetrahydrobiopterin in RAW 264.7 cells.

Studies on the effect of ascorbic acid on inducible nitric oxide synthase (iNOS) activity are few and diverse, likely to be dependent on the species of cells. We investigated a role of ascorbic acid in iNOS induction and nitric oxide (NO) generation in mouse macrophage cell line RAW 264.7. Although interferon- (IFN-) gamma alone produced NO end products, ascorbic acid enhanced NO production only when cells were synergistically stimulated with IFN-gamma plus Escherichia coli lipopolysaccharide (LPS). Ascorbate neither enhanced nor decreased the expression of iNOS protein in RAW 264.7 cells, in contrast to the reports that ascorbic acid augments iNOS induction in a mouse macrophage-like cell line J774.1 and that ascorbate suppresses iNOS induction in rat skeletal muscle endothelial cells. Intracellular levels of tetrahydrobiopterin (BH4), a cofactor for iNOS, were increased by ascorbate in RAW 264.7 cells. However, ascorbate did not increase GTP cyclohydrolase I mRNA, the main enzyme at the critical steps in the BH4 synthetic pathway, expression levels and activity. Sepiapterin, which supplies BH4 via salvage pathway, more efficiently enhanced NO production if ascorbate was added. These data suggest that enhanced activation of iNOS by ascorbic acid is mediated by increasing the stability of BH4 in RAW 264.7 cells.

Effects of high glucose on NO synthesis in human keratinocyte cell line (HaCaT).

BACKGROUND There is a possibility that alteration of nitric oxide (NO) synthesis by high glucose leads to a variety of diabetic complications. OBJECTIVE In this study, we examined whether NO synthesis is altered by high glucose in spontaneously immortalized human keratinocyte cell line (HaCaT) that have three isoforms of NO synthases (NOS). METHODS We measured NO end product nitrite in the culture medium using the Griess reagent and analyzed mRNA expression of three isoforms of NOS in HaCaT cells by RT-PCR. RESULTS High glucose enhanced constitutively produced NO production in HaCaT cells, which persisted for 10 days and was attenuated by an inhibitor of protein kinase C (PKC), without altering eNOS/nNOS mRNA levels. Cytokine stimulation induced iNOS mRNA in HaCaT cells. Pretreatment with high glucose for 24 h enhanced cytokine-induced NO production in HaCaT cells. However, when these cells were exposed to high glucose for 10 days, cytokine treatment did not induce iNOS mRNA and nitrite production. CONCLUSION These diverse alterations in NO production by high glucose may be involved in impaired host-defense and wound healing in the skin of diabetic patients.

Angiotensin II enhances EGF receptor expression levels via ROS formation in HaCaT cells

BACKGROUND Recent work has shown a novel function of angiotensin II (Ang II) in skin wound healing in which reactive oxygen species might be involved. As Ang II is known to increase superoxide production by activating NADPH oxidase in some non-phagocytic cells, we hypothesized that the produced superoxide by NADPH activation could contribute to the regulation of epidermal growth factor receptor (EGFR) in keratinocytes. OBJECTIVE We examined whether Ang II could generate superoxide and enhance EGFR expression levels in HaCaT cells. METHODS Superoxide formation was assessed by using hydroethidine. EGFR expression levels were examined by Western blotting. RESULTS Ang II (1-100 microM) increased the superoxide formation. Ang II (1-100 microM) resulted in a dose-dependent increase in cell proliferation in HaCaT cells. Heparin-binding epidermal growth factor activated the EGFR at 5-10 min. Although Ang II did not activate the EGFR, the expression levels of EGFR protein were increased in HaCaT cells treated with Ang II (1 microM) at 6h. Apocynin, a NADPH oxidase inhibitor, decreased the expression levels of EGFR. Xanthine/xanthine oxidase system, an exogenous superoxide generating system, enhanced the EGFR protein expression. Although Ang II did not affect the nitric oxide (NO) production, a NO synthase inhibitor N(omega)-nitro-l-arginine methyl ester suppressed the Ang II-induced EGFR expression levels in HaCaT cells. Thus, constitutive NO is required for the Ang II-induced EGFR expression in HaCaT cells. CONCLUSION These results suggest that Ang II enhances the cell proliferation and EGFR expression via superoxide production under the regulation of NO in HaCaT cells, implying that Ang II may regulate the proliferation, differentiation and tumorigenesis of the epidermis by harmonizing the superoxide and NO production.

Sepsis-induced hypercytokinemia and lymphocyte apoptosis in aging-accelerated Klotho knockout mice.

ABSTRACT Sepsis is primarily a disease of the aged, with 65% of sepsis cases reported in patients older than 65 years and 80% of deaths due to sepsis occurring in this age group. Klotho knockout mice (Klotho mice) are a mouse model of accelerated aging and shortened life span. The purpose of the study was to elucidate the immunological changes occurring in Klotho mice during sepsis. Five-week-old homozygous female Klotho knockout (Klotho) and wild-type (WT) mice were subjected to 1 × 27-gauge cecal ligation and puncture (CLP), and survival was compared after 4 days. Another set of mice was killed at 8 h after CLP or sham surgery, and the spleen, thymus, and serum were harvested. Apoptosis was measured by flow cytometry by using caspase 3. Serum cytokines and bacterial colony count in peritoneal lavage were also analyzed. Klotho septic mice started to die at 8 to 12 h after CLP, and the final survival of Klotho mice was significantly lower than that of WT mice (0% vs. 100%, P < 0.01). Increased bacterial count in the peritoneal cavity and decreased recruitment of neutrophils and macrophages to the peripheral cavity were observed in Klotho-CLP mice. Both flow cytometric and immunohistological analyses showed a dramatic increase in caspase 3–positive cells in the thymus and spleen of Klotho-CLP mice (P < 0.01). Serum concentrations of interleukin 6, tumor necrosis factor &agr;, and interleukin 10 were higher in Klotho-CLP mice than in WT-CLP mice. Hypercytokinemia with impaired bacterial clearance and increased apoptosis of lymphocytes may be related to poor survival in Klotho-septic mice.