15 学校ボランティア通信 No.3

発行日：2006年9月26

Targeting miR-223 in neutrophils enhances the clearance of Staphylococcus aureus in infected wounds

Abstract Argonaute 2 bound mature microRNA (Ago2‐miRNA) complexes are key regulators of the wound inflammatory response and function in the translational processing of target mRNAs. In this study, we identified four wound inflammation‐related Ago2‐miRNAs (miR‐139‐5p, miR‐142‐3p, miR‐142‐5p, and miR‐223) and show that miR‐223 is critical for infection control. miR‐223Y/− mice exhibited delayed sterile healing with prolonged neutrophil activation and interleukin‐6 expression, and markedly improved repair of Staphylococcus aureus‐infected wounds. We also showed that the expression of miR‐223 was regulated by CCAAT/enhancer binding protein alpha in human neutrophils after exposure to S. aureus peptides. Treatment with miR‐223Y/−‐derived neutrophils, or miR‐223 antisense oligodeoxynucleotides in S. aureus‐infected wild‐type wounds markedly improved the healing of these otherwise chronic, slow healing wounds. This study reveals how miR‐223 regulates the bactericidal capacity of neutrophils at wound sites and indicates that targeting miR‐223 might be of therapeutic benefit for infected wounds in the clinic

ROS induced Cbl-b expression in rat L6 cells

Unloading-mediated muscle atrophy is associated with increased reactive oxygen species (ROS) production. We previously demonstrated that elevated ubiquitin ligase casitas B-lineage lymphoma-b (Cbl-b) resulted in the loss of muscle volume (Nakao R, Hirasaka K, Goto J, Ishidoh K, Yamada C, Ohno A, Okumura Y, Nonaka I, Yasutomo K, Baldwin KM, Kominami E, Higashibata A, Nagano K, Tanaka K, Yasui N, Mills EM, Takeda S, Nikawa T. Mol Cell Biol 29: 4798–4811, 2009). However, the pathological role of ROS production associated with unloading-mediated muscle atrophy still remains unknown. Here, we showed that the ROS-mediated signal transduction caused by microgravity or its simulation contributes to Cbl-b expression. In L6 myotubes, the assessment of redox status revealed that oxidized glutathione was increased under microgravity conditions, and simulated microgravity caused a burst of ROS, implicating ROS as a critical upstream mediator linking to downstream atrophic signaling. ROS generation activated the ERK1/2 early-growth response protein (Egr)1/2-Cbl-b signaling pathway, an established contributing pathway to muscle volume loss. Interestingly, antioxidant treatments such as N-acetylcysteine and TEMPOL, but not catalase, blocked the clinorotation-mediated activation of ERK1/2. The increased ROS induced transcriptional activity of Egr1 and/or Egr2 to stimulate Cbl-b expression through the ERK1/2 pathway in L6 myoblasts, since treatment with Egr1/2 siRNA and an ERK1/2 inhibitor significantly suppressed clinorotation-induced Cbl-b and Egr expression, respectively. Promoter and gel mobility shift assays revealed that Cbl-b was upregulated via an Egr consensus oxidative responsive element at −110 to −60 bp of the Cbl-b promoter. Together, this indicates that under microgravity conditions, elevated ROS may be a crucial mechanotransducer in skeletal muscle cells, regulating muscle mass through Cbl-b expression activated by the ERK-Egr signaling pathway

Reduced FOXO1 Expression Accelerates Skin Wound Healing and Attenuates Scarring

The forkhead box O (FOXO) family has been extensively investigated in aging and metabolism, but its role in tissue-repair processes remains largely unknown. Herein, we clarify the molecular aspect of the FOXO family in skin wound healing. We demonstrated that Foxo1 and Foxo3a were both up-regulated during murine skin wound healing. Partial knockout of Foxo1 in Foxo1 +/- mice throughout the body led to accelerated skin wound healing with enhanced keratinocyte migration, reduced granulation tissue formation, and decreased collagen density, accompanied by an attenuated inflammatory response, but we observed no wound phenotype in Foxo3a-/- mice. Fibroblast growth factor 2, adiponectin, and notch1 genes were significantly increased at wound sites in Foxo1+/- mice, along with markedly altered extracellular signal-regulated kinase 1/2 and AKT phosphorylation. Similarly, transient knockdown of Foxo1 at the wound site by local delivery of antisense oligodeoxynucleotides enhanced skin wound healing. The link between FOXO1 and scarring extends to patients, in particular keloid scars, where we see FOXO1 expression markedly increased in fibroblasts and inflammatory cells within the otherwise normal dermis. This occurs in the immediate vicinity of the keloid by comparison to the center of the mature keloid, indicating that FOXO1 is associated with the overgrowth of this fibrotic response into adjacent normal skin. Overall, our data indicate that molecular targeting of FOXO1 may improve the quality of healing and reduce pathological scarring

A new experimental model of ATP-sensitive K+ channel-independent insulinotropic action of glucose: a permissive role of cAMP for triggering of insulin release from rat pancreatic beta-cells

信州大学博士（医学）・学位論文・平成24年3月31日授与（甲第936号）・武井 真大In pancreatic beta-cells, glucose metabolism leads to closure of ATP sensitive K+ channels (K-ATP channel) and Ca2+ influx, which is regarded as a required step for triggering of insulin release. Here, we demonstrate that glucose triggers rapid insulin release independent from its action on K-ATP channels given the cellular cAMP is elevated. We measured insulin release from rat pancreatic islets by static and perifusion experiments. Changes in cytosolic free Ca2+ concentration ([Ca2+](i)) were monitored using fura-2 loaded rat pancreatic beta-cells. Glucose-induced insulin release was abolished when Ca2+ influx was inhibited by a combination of 250 mu M diazoxide, an opener of K-ATP channel, and 10 mu M nifedipine, a blocker of L-type voltage-dependent Ca2+ channels. However, with both nifedipine and diazoxide, glucose induced a 5-fold increase in insulin release in the presence of 10 mu M forskolin, an activator of adenylyl cyclase. In the presence of diazoxide, nifedipine, and forskolin, 22 mM glucose sharply increased the rate of insulin release within 2 min which peaked at 6 min: this was followed by a further gradual increase in insulin release. In contrast, it lowered [Ca2+](i) with a nadir at 2-3 min followed by a gradual increase in [Ca2+](i). The glucose effect was mimicked by 20 mM alpha-ketoisocaproic acid, a mitochondrial fuel, and it was nullified by 2 mM sodium azide, an inhibitor of mitochondrial electron transport. Cerulenin, an inhibitor of protein acylation, decreased the glucose effect. In conclusion, a rise in [Ca2+](i) through voltage-dependent Ca2+ channels is not mandatory for glucose-induced triggering of insulin release.ArticleENDOCRINE JOURNAL. 60(5):599-607 (2013)journal articl

Exposure of titanium implants after cranioplasty: A matter of long-term consequences

Although the use of titanium implants in cranioplasty has recently become common, long-term results of this strategy are sometimes difficult to manage. The aim of this study was to clarify the characteristics of patients developing exposure of titanium implants. Records of eight patients with exposure of titanium implants were reviewed. Patient ages ranged from 41 to 77 (mean, 56.8) years. Two patients were male, and six were female. The periods from implantation to exposure of titanium implants ranged from 5 to 87 (mean, 30.5) months. In seven cases, titanium mesh cranioplasty was performed after postcraniotomy infections. The titanium implants were removed in all cases. Scalp tissue was closed by applying a primary closure technique in five cases, though scalp reconstruction was performed with a rotation flap in the other three cases involving large scalp ulceration. Although the use of titanium implants is convenient, the indications should be carefully considered, especially in cases with postoperative surgical site infections and in patients with thin scalp skin. For these patients, long-term follow up is necessary

Prevalence of and risk factors for enlarged perivascular spaces in adult patients with moyamoya disease

Abstract Background Enlarged perivascular spaces (EPVS) are often observed with magnetic resonance imaging in patients with small vessel disease. However, the risk factors, radiological features, and clinical relevance of EPVS in patients with moyamoya disease are poorly understood. The purpose of this study was to evaluate EPVS, the risk factors of many EPVS, and the pathophysiology of EPVS in adult patients with moyamoya disease. Methods One hundred cerebral hemispheres of 50 adult patients with moyamoya disease were examined. The control group consisted of 50 age/sex-matched patients without ischemic disease. The numbers of EPVS at the level of the centrum semiovale per hemisphere were compared between the moyamoya disease and control groups. In each hemisphere, the total numbers of EPVS were categorized into five grades (0–4), and the clinical and radiological characteristics of the predictive factors in patients in the high EPVS grade group (EPVS grade = 4) were assessed. Results The EPVS counts and grades were significantly higher in the moyamoya disease group. Analyses of the background characteristics of the patients with moyamoya disease revealed that significantly higher prevalence of high EPVS grades were associated with the female sex, hypertension, high magnetic resonance angiography scores, high numbers of flow voids in the basal ganglia, high brain atrophy scores, ivy signs, and white matter lesions. A logistic multivariate analysis of the patients with high EPVS grades revealed significant associations with the female sex, hypertension, and flow voids in the basal ganglia. Conclusions Increased EPVS were confirmed in adult patients with moyamoya disease, and the associated clinical and radiological factors were identified. The presence of hypertension, the female sex, and flow voids in the basal ganglia were important for predicting high EPVS grades in patients with moyamoya disease. Reductions in arterial pulsations with steno-occlusive changes can inhibit the flow of interstitial fluid, which can increase the number of EPVS in patients with moyamoya disease. Other clinical factors, such as the female sex and hypertension, may promote secondary brain damage in patients with moyamoya disease. Further evaluations of EPVS in patients with moyamoya disease are needed to better understand their pathophysiological importance