ヒマン トウニョウビョウ モデル マウス オヨビ 3T3-L1 ゼンク シボウ サイボウ ニ オケル サクサン ニ ヨル ブラウニング ユウドウ ノ ケントウ

博士（医学）熊本大

Impacts of the 2016 Kumamoto Earthquake on glycemic control in patients with diabetes

Abstract Aims/Introduction On April 14 and 16 2016, the Kumamoto area was severely damaged by several massive magnitude 7 class earthquakes. Materials and Methods To examine the effects of these earthquakes on glycemic control and stress factors, glycated hemoglobin, glycated albumin, other biochemical parameters, a self‐administered lifestyle‐associated questionnaire and disaster‐associated stress scores were analyzed. A total of 557 patients with diabetes were enrolled, and data were collected at 13 months before to 13 months after the earthquakes. Results In patients with type 1 diabetes and specific types of diabetes due to other causes, glycemic control was not altered during the observational period. This glycemic stability in type 1 diabetes might result from self‐management of insulin doses. In patients with type 2 diabetes, glycated hemoglobin decreased by 0.11% (from 7.33 to 7.22%) at 1–2 months after the earthquakes, and increased thereafter. The reduction of glycated hemoglobin after 1–2 months in type 2 diabetes was associated with ‘early restoration of lifelines’ and ‘sufficient sleep.’ The glycemic deterioration at a later stage was related to ‘shortage of antidiabetic agents,’ ‘insufficient amount of food,’ ‘largely destroyed houses’ and ‘changes in working environments.’ Disaster‐associated stress levels were positively correlated with ‘age,’ ‘delayed restoration of lifelines,’ ‘self‐management of antidiabetic agents’ and ‘increased amount of physical activity/exercise,’ and negatively associated with ‘early restoration of lifelines’ and ‘sufficient sleep.’ Conclusions Glycemic control, associated factors and stress levels are altered in chronological order. Post‐disaster diabetic medical care must consider these corresponding points in accordance with the time‐period

Identification of microRNA that represses IRS-1 expression in liver.

MicroRNAs (miRNAs) are short, non-coding RNAs that post-transcriptionally regulate gene expression and have been shown to participate in almost every cellular process. Several miRNAs have recently been implicated in glucose metabolism, but the roles of miRNAs in insulin-resistant conditions, such as obesity or type 2 diabetes, are largely unknown. Herein, we focused on miR-222, the expression of which was increased in the livers of high fat/high sucrose diet-fed mice injected with gold thioglucose (G+HFHSD). Overexpression of miR-222 in primary mouse hepatocytes attenuated Akt phosphorylation induced by insulin, indicating that miR-222 negatively regulates insulin signaling. As per in silico analysis, miR-222 potentially binds to the 3' untranslated region (3' UTR) of the IRS-1 gene, a key insulin signaling molecule. In fact, IRS-1 protein expression was decreased in the livers of G+HFHSD-fed mice. We further confirmed a direct interaction between miR-222 and the 3' UTR of IRS-1 via luciferase assays. Our findings suggest that up-regulation of miR-222 followed by reduction in IRS-1 expression may be a viable mechanism of insulin resistance in the liver

Effect of miR-222 overexpression on insulin signaling in primary mouse hepatocytes.

<p>(A) Primary hepatocytes were transfected with 30 nM negative control oligos (control) or miR-222 mimic using HilyMax. After 2 days of transfection, miR-222 overexpression in the cells was confirmed by qRT-PCR (n = 6 per group). (B) Cells overexpressing miR-222 were treated with insulin (100 nM) for 10 min. Cells were harvested, and protein levels involved in insulin signaling were determined by WB. The IRS-1 and P-Akt levels were quantified by normalization with β-actin and total Akt. The values are expressed as mean ± SD from 4 independent experiments. (C) <i>Irs-1</i> and <i>Irs-2</i> mRNA expression in the cells overexpressing miR-222 were analyzed by qRT-PCR. (D) Each mRNA involved in insulin signaling was analyzed in the cells overexpressing miR-222 (n = 10 per group). Data are presented as means ± SD. *<i>p</i> < 0.05, **<i>p</i> < 0.01 compared with the control group.</p

miR-222 expression is up-regulated in the livers of G+HFHSD-fed mice.

<p>(A) Body weight was measured during each treatment in NC or G+HFHSD-fed mice (n = 7–8 per group). (B, C) Fasting blood glucose and insulin levels were measured after 24 weeks of treatment. (D) HOMA-IR was calculated using fasting blood glucose and insulin levels after 24 weeks of treatment. (E, F) After 24 weeks of treatment, microRNA was collected from the livers of these mice. miR-222 and miR-221 expression were analyzed by qRT-PCR (n = 8 per group). (G) The proteins in the livers of these mice were analyzed with WB. The IRS-1 and IRS-2 levels were quantified by normalization with β-actin. (n = 4 per group). (H) <i>Irs-1</i> mRNA expression in the livers of these mice were analyzed by qRT-PCR. Data are presented as mean ± SD. *<i>p</i> < 0.05, **<i>p</i> < 0.01 compared with NC-fed mice.</p

Effect of miR-222 overexpression on insulin signaling in primary mouse hepatocytes.

<p>(A) Primary hepatocytes were transfected with 30 nM negative control oligos (control) or miR-222 mimic using HilyMax. After 2 days of transfection, miR-222 overexpression in the cells was confirmed by qRT-PCR (n = 6 per group). (B) Cells overexpressing miR-222 were treated with insulin (100 nM) for 10 min. Cells were harvested, and protein levels involved in insulin signaling were determined by WB. The IRS-1 and P-Akt levels were quantified by normalization with β-actin and total Akt. The values are expressed as mean ± SD from 4 independent experiments. (C) <i>Irs-1</i> and <i>Irs-2</i> mRNA expression in the cells overexpressing miR-222 were analyzed by qRT-PCR. (D) Each mRNA involved in insulin signaling was analyzed in the cells overexpressing miR-222 (n = 10 per group). Data are presented as means ± SD. *<i>p</i> < 0.05, **<i>p</i> < 0.01 compared with the control group.</p

Effect of miR-222 overexpression in HuH-7 cells.

<p>(A) HuH-7 cells were transfected with 30 nM of the negative control or miR-222 mimic. After 2 days of transfection, miR-222 overexpression was confirmed by qRT-PCR (n = 6 per group). (B) Cells overexpressing miR-222 were treated with insulin (100 nM) for 10 min. Cells were harvested, and protein levels involved in insulin signaling were determined with WB. The IRS-1 and P-Akt levels were quantified by normalization with β-actin and total Akt. The values are expressed as the mean ± SD from 4 independent experiments. (C) The pmirGLO-based 3' UTR reporter vector consisted of luciferase cDNA followed by the 3' UTR of the WT or Mut human <i>IRS-1</i> mRNA. (D) HEK-293 cells were co-transfected with the luciferase reporter construct containing WT or Mut 3' UTR of human <i>IRS-1</i> and the miR-222 mimic or the negative control oligos. After 2 days of treatment, a dual-luciferase assay of these cells was measured (n = 10 per group). Data are presented as mean ± SD. *<i>p</i> < 0.05, **<i>p</i> < 0.01 compared with the control group.</p