scholarly journals Intramuscular Injection of miR-1 Reduces Insulin Resistance in Obese Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Alice C. Rodrigues ◽  
Alexandre R. Spagnol ◽  
Flávia de Toledo Frias ◽  
Mariana de Mendonça ◽  
Hygor N. Araújo ◽  
...  

The role of microRNAs in metabolic diseases has been recognized and modulation of them could be a promising strategy to treat obesity and obesity-related diseases. The major purpose of this study was to test the hypothesis that intramuscular miR-1 precursor replacement therapy could improve metabolic parameters of mice fed a high-fat diet. To this end, we first injected miR-1 precursor intramuscularly in high-fat diet-fed mice and evaluated glucose tolerance, insulin sensitivity, and adiposity. miR-1-treated mice did not lose weight but had improved insulin sensitivity measured by insulin tolerance test. Next, using an in vitro model of insulin resistance by treating C2C12 cells with palmitic acid (PA), we overexpressed miR-1 and measured p-Akt content and the transcription levels of a protein related to fatty acid oxidation. We found that miR-1 could not restore insulin sensitivity in C2C12 cells, as indicated by p-Akt levels and that miR-1 increased expression of Pgc1a and Cpt1b in PA-treated cells, suggesting a possible role of miR-1 in mitochondrial respiration. Finally, we analyzed mitochondrial oxygen consumption in primary skeletal muscle cells treated with PA and transfected with or without miR-1 mimic. PA-treated cells showed reduced basal respiration, oxygen consumption rate-linked ATP production, maximal and spare capacity, and miR-1 overexpression could prevent impairments in mitochondrial respiration. Our data suggest a role of miR-1 in systemic insulin sensitivity and a new function of miR-1 in regulating mitochondrial respiration in skeletal muscle.

2017 ◽  
Vol 313 (5) ◽  
pp. E552-E562 ◽  
Author(s):  
Sean A. Newsom ◽  
Benjamin F. Miller ◽  
Karyn L. Hamilton ◽  
Sarah E. Ehrlicher ◽  
Harrison D. Stierwalt ◽  
...  

Skeletal muscle mitochondrial protein synthesis is regulated in part by insulin. The development of insulin resistance with diet-induced obesity may therefore contribute to impairments to protein synthesis and decreased mitochondrial respiration. Yet the impact of diet-induced obesity and insulin resistance on mitochondrial energetics is controversial, with reports varying from decreases to increases in mitochondrial respiration. We investigated the impact of changes in insulin sensitivity on long-term rates of mitochondrial protein synthesis as a mechanism for changes to mitochondrial respiration in skeletal muscle. Insulin resistance was induced in C57BL/6J mice using 4 wk of a high-fat compared with a low-fat diet. For 8 additional weeks, diets were enriched with pioglitazone to restore insulin sensitivity compared with nonenriched control low-fat or high-fat diets. Skeletal muscle mitochondrial protein synthesis was measured using deuterium oxide labeling during weeks 10–12. High-resolution respirometry was performed using palmitoyl-l-carnitine, glutamate+malate, and glutamate+malate+succinate as substrates for mitochondria isolated from quadriceps. Mitochondrial protein synthesis and palmitoyl- l-carnitine oxidation were increased in mice consuming a high-fat diet, regardless of differences in insulin sensitivity with pioglitazone treatment. There was no effect of diet or pioglitazone treatment on ADP-stimulated respiration or H2O2 emission using glutamate+malate or glutamate+malate+succinate. The results demonstrate no impairments to mitochondrial protein synthesis or respiration following induction of insulin resistance. Instead, mitochondrial protein synthesis was increased with a high-fat diet and may contribute to remodeling of the mitochondria to increase lipid oxidation capacity. Mitochondrial adaptations with a high-fat diet appear driven by nutrient availability, not intrinsic defects that contribute to insulin resistance.


2019 ◽  
Vol 317 (6) ◽  
pp. E973-E983 ◽  
Author(s):  
Annie Hasib ◽  
Chandani K. Hennayake ◽  
Deanna P. Bracy ◽  
Aimée R. Bugler-Lamb ◽  
Louise Lantier ◽  
...  

Extracellular matrix hyaluronan is increased in skeletal muscle of high-fat-fed insulin-resistant mice, and reduction of hyaluronan by PEGPH20 hyaluronidase ameliorates diet-induced insulin resistance (IR). CD44, the main hyaluronan receptor, is positively correlated with type 2 diabetes. This study determines the role of CD44 in skeletal muscle IR. Global CD44-deficient ( cd44−/−) mice and wild-type littermates ( cd44+/+) were fed a chow diet or 60% high-fat diet for 16 wk. High-fat-fed cd44−/− mice were also treated with PEGPH20 to evaluate its CD44-dependent action. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp (ICv). High-fat feeding increased muscle CD44 protein expression. In the absence of differences in body weight and composition, despite lower clamp insulin during ICv, the cd44−/− mice had sustained glucose infusion rate (GIR) regardless of diet. High-fat diet-induced muscle IR as evidenced by decreased muscle glucose uptake (Rg) was exhibited in cd44+/+ mice but absent in cd44−/− mice. Moreover, gastrocnemius Rg remained unchanged between genotypes on chow diet but was increased in high-fat-fed cd44−/− compared with cd44+/+ when normalized to clamp insulin concentrations. Ameliorated muscle IR in high-fat-fed cd44−/− mice was associated with increased vascularization. In contrast to previously observed increases in wild-type mice, PEGPH20 treatment in high-fat-fed cd44−/− mice did not change GIR or muscle Rg during ICv, suggesting a CD44-dependent action. In conclusion, genetic CD44 deletion improves muscle IR, and the beneficial effects of PEGPH20 are CD44-dependent. These results suggest a critical role of CD44 in promoting hyaluronan-mediated muscle IR, therefore representing a potential therapeutic target for diabetes.


2019 ◽  
Vol 317 (6) ◽  
pp. C1172-C1182 ◽  
Author(s):  
Min-Gyeong Shin ◽  
Hye-Na Cha ◽  
Soyoung Park ◽  
Yong-Woon Kim ◽  
Jong-Yeon Kim ◽  
...  

Selenoprotein W (SelW) is a selenium-containing protein with a redox motif found abundantly in the skeletal muscle of rodents. Previous in vitro studies suggest that SelW plays an antioxidant role; however, relatively few in vivo studies have addressed the antioxidant role of SelW. Since oxidative stress is a causative factor for the development of insulin resistance in obese subjects, we hypothesized that if SelW plays a role as an antioxidant, SelW deficiency could aggravate the oxidative stress and insulin resistance caused by a high-fat diet. SelW deficiency did not affect insulin sensitivity and H2O2 levels in the skeletal muscle of control diet-fed mice. SelW levels in the skeletal muscle were decreased by high-fat diet feeding for 12 wk. High-fat diet induced obesity and insulin resistance and increased the levels of H2O2 and oxidative stress makers, which were not affected by SelW deficiency. High-fat diet feeding increased the expression of antioxidant enzymes; however, SelW deficiency did not affect the expression levels of antioxidants. These results suggest that SelW does not play a protective role against oxidative stress and insulin resistance in the skeletal muscle of high-fat diet-fed obese mice.


2010 ◽  
Vol 35 (2) ◽  
pp. 151-162 ◽  
Author(s):  
Scott P. Naples ◽  
Sarah J. Borengasser ◽  
R. Scott. Rector ◽  
Grace M. Uptergrove ◽  
E. Matthew Morris ◽  
...  

Rats selected artificially to be low-capacity runners (LCR) possess a metabolic syndrome phenotype that is worsened by a high-fat diet (HFD), whereas rats selected to be high-capacity runners (HCR) are protected against HFD-induced obesity and insulin resistance. This study examined whether protection against, or susceptibility to, HFD-induced insulin resistance in the HCR–LCR strains is associated with contrasting metabolic adaptations in skeletal muscle. HCR and LCR rats (generation 20; n = 5–6; maximum running distance ∼1800 m vs. ∼350 m, respectively (p < 0.0001)) were divided into HFD (71.6% energy from fat) or normal chow (NC) (16.7% energy from fat) groups for 7 weeks (from 24 to 31 weeks of age). Skeletal muscle (red gastrocnemius) mitochondrial-fatty acid oxidation (FAO), mitochondrial-enzyme activity, mitochondrial-morphology, peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), and peroxisome proliferator-activated receptor δ (PPARδ) expression and insulin sensitivity (intraperitoneal glucose tolerance tests) were measured. The HFD caused increased adiposity and reduced insulin sensitivity only in the LCR and not the HCR strain. Isolated mitochondria from the HCR skeletal muscle displayed a 2-fold-higher rate of FAO on NC, but both groups increased FAO following HFD. PGC-1α mRNA expression and superoxide dismutase activity were significantly reduced with the HFD in the LCR rats, but not in the HCR rats. PPARδ expression did not differ between strains or dietary conditions. These results do not provide a clear connection between protection of insulin sensitivity and HFD-induced adaptive changes in mitochondrial function or transcriptional responses but do not dismiss the possibility that elevated mitochondrial FAO in the HCR may play a protective role.


Endocrinology ◽  
2012 ◽  
Vol 153 (11) ◽  
pp. 5261-5274 ◽  
Author(s):  
M. A. Carvalho-Filho ◽  
B. M. Carvalho ◽  
A. G. Oliveira ◽  
D. Guadagnini ◽  
M. Ueno ◽  
...  

Abstract The molecular integration of nutrient- and pathogen-sensing pathways has become of great interest in understanding the mechanisms of insulin resistance in obesity. The double-stranded RNA-dependent protein kinase (PKR) is one candidate molecule that may provide cross talk between inflammatory and metabolic signaling. The present study was performed to determine, first, the role of PKR in modulating insulin action and glucose metabolism in physiological situations, and second, the role of PKR in insulin resistance in obese mice. We used Pkr−/− and Pkr+/+ mice to investigate the role of PKR in modulating insulin sensitivity, glucose metabolism, and insulin signaling in liver, muscle, and adipose tissue in response to a high-fat diet. Our data show that in lean Pkr−/− mice, there is an improvement in insulin sensitivity, and in glucose tolerance, and a reduction in fasting blood glucose, probably related to a decrease in protein phosphatase 2A activity and a parallel increase in insulin-induced thymoma viral oncogene-1 (Akt) phosphorylation. PKR is activated in tissues of obese mice and can induce insulin resistance by directly binding to and inducing insulin receptor substrate (IRS)-1 serine307 phosphorylation or indirectly through modulation of c-Jun N-terminal kinase and inhibitor of κB kinase β. Pkr−/− mice were protected from high-fat diet-induced insulin resistance and glucose intolerance and showed improved insulin signaling associated with a reduction in c-Jun N-terminal kinase and inhibitor of κB kinase β phosphorylation in insulin-sensitive tissues. PKR may have a role in insulin sensitivity under normal physiological conditions, probably by modulating protein phosphatase 2A activity and serine-threonine kinase phosphorylation, and certainly, this kinase may represent a central mechanism for the integration of pathogen response and innate immunity with insulin action and metabolic pathways that are critical in obesity.


2021 ◽  
Author(s):  
Xv Han ◽  
Qingguang Chen ◽  
Yahua Liu ◽  
Junfei Xv ◽  
Hao Lu

Abstract Background:IMCLs are an important factor in skeletal muscle insulin resistance. This study aimed to explore the effect of Jianpi Qinghua formula (JPQHF) on IMCLs and its mechanism, as well as the relationship between IMCLs and other skeletal muscle insulin sensitivity factors, thereby elucidating the mechanism by which JPQHF improves insulin sensitivity.Methods: In an in vivo experiment, JPQHF and pioglitazone (PIO) were individually used to treat C57 mice with high-fat diet-induced obesity. In an in vitro experiment, JPQHF and rapamycin in serum were individually used to treat C2C12 cells induced with palmitic acid. The IMCLs of tissue and cells were subjected to oil red O staining. The RNA and protein expression of PPARγ, myogenin, mTORC1 and members of the PI3K/AKT pathway in skeletal muscle tissue and C2C12 cells was examined. Differences between the different intervention groups were determined.Results: IMCLs were significantly increased in mice with obesity induced by a high-fat diet and the C2C12 cell line treated with palmitic acid compared to the corresponding controls. mTORC1 phosphorylation and PPARγ levels were also increased, and AKT phosphorylation and myogenin levels were decreased. Intervention with JPQHF reversed the above changes. In addition, the PPARγ level in C2C12 cells was reduced after intervention with rapamycin, an inhibitor of mTORC1. However, AKT phosphorylation and myogenin levels did not recover after rapamycin intervention.Conclusion: IMCLs were significantly increased in obese C57 mice and palmitic acid-treated C2C12 cells. JPQHF reduced IMCLs both in vivo and in vitro. Mechanistically, this effect likely occurred through JPQHF-mediated inhibition of the overactivation of mTORC1 and a subsequent reduction in the expression of PPARγ. However, the function of JPQHF in elevating myogenin levels and the PI3K/AKT pathway may not be entirely dependent on mTORC1.


2021 ◽  
Vol 11 ◽  
Author(s):  
Jiali Yang ◽  
Yunhui Ran ◽  
Yonghui Yang ◽  
Shuyi Song ◽  
Yahong Wu ◽  
...  

In obesity, macrophages and other immune cells accumulate in organs affected by insulin, leading to chronic inflammation and insulin resistance. 4-Hydroxyisoleucine (4-HIL) is a non-protein amino acid found in fenugreek seeds. 4-HIL enhances insulin sensitivity, but its mechanism is still unclear. In this study, 4-HIL intervention reduced weight gain, liver steatosis, and dyslipidemia; moreover, it increased systemic insulin sensitivity and improved insulin resistance in mice. Importantly, after administration, the accumulation of M1 like CD11c+ macrophages and inflammation in the liver and adipose tissue were reduced in the mice. 4-HIL also reduced the proportion of CD11c+ macrophages among bone marrow-derived macrophages, which were induced in vitro. These observations demonstrate a new role of 4-HIL in insulin resistance in hepatocytes and adipocytes. 4-HIL inhibits obesity-related insulin resistance by reducing inflammation and regulating the state of M1/M2 macrophages.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Janine Krüger ◽  
Markus Dagnell ◽  
Philipp Stawowy ◽  
Evren Caglayan ◽  
Arne Östman ◽  
...  

Background: Insulin resistance plays a crucial role in the development of type 2 diabetes, and exerts great impact on vascular inflammation and remodeling. At the molecular level a post-insulin receptor (IR) defect in insulin signaling has been suggested to contribute to insulin resistance. IR signaling is antagonized and tightly controlled by protein tyrosine phosphatases (PTPs). The precise role of PTPs in insulin resistance, however, has not been explored. Results: Male C57BL/6J mice were fed a high-fat diet (HFD, 60% kcal from fat) to induce insulin resistance, or a low-fat diet (LFD, 10% kcal from fat) for 10 weeks. Afterwards, HFD mice were treated with PTP-inhibitors for additional 6 weeks. Mice under HFD exhibited a significant increase in body weight as well as decreased respiratory quotient and adiponectin levels, and were characterized by impaired insulin- and glucose tolerance. Organ-based gene expression analyses in insulin-resistant mice demonstrated upregulation of SHP-1, PTP1B, LAR, and DEP-1 in insulin-sensitive organs. SHP-1 was further explored in vitro. Insulin stimulation in murine liver cells induced site-selective hyper-phosphorylation at IR tyrosine-sites Y1158, and Y1361 after inhibition of SHP-1. Furthermore, SHP-1 impairment time-dependently enhanced insulin-induced Akt- and Erk-phosphorylation, and resulted in elevated glucose uptake in skeletal muscle cells. Administration of a SHP-1 inhibitor (Sodium Stibogluconate) and a brought pan-PTP inhibitor (BMOV) in HFD mice led to improvement of both insulin- and glucose tolerance. In accordance, PTP-activity was significantly impaired in epididymal fat, skeletal muscle, and liver under BMOV treatment, being confirmed by reduced ex vivo dephosphorylation of a radioactive labelled peptide (AEEEIYGEFEAKKKK). Finally, BMOV- and SHP-1 treatment also resulted in reduced body weight. Conclusions: IR-antagonizing PTPs were organ-specifically regulated in insulin resistance. The results indicate a central role of PTPs and, in particular, of SHP-1 as endogenous antagonists of the IR. Taken together targeting PTPs led to beneficial effects in insulin resistance, and may thus improve metabolic diseases as well as cardiovascular morbidity and mortality.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xiao-Kang Jia ◽  
Jin-Fang Huang ◽  
Xiao-Qiang Huang ◽  
Xiao-Yan Li ◽  
Ming-Qing Huang ◽  
...  

Alismatis rhizoma (AR), which is the dried rhizome of Alisma orientale (Sam.) Juz. (Alismataceae), is an important component of many famous Chinese formulas for hypoglycemic. This study aimed to evaluate the insulin resistance (IR) alleviating effects of AR triterpenes (ART) and ART component compatibility (ARTC, the mixture of 16-oxo-alisol A, 16-oxo-alisol A 23-acetate, 16-oxo-alisol A 24-acetate, alisol C, alisol C 23-acetate, alisol L, alisol A, alisol A 23-acetate, alisol A 24-acetate, alisol L 23-acetate, alisol B, alisol B 23-acetate, 11-deoxy-alisol B and 11-deoxy-alisol B 23-acetate) in high-fat diet-induced IR mice and plamitate-treated IR C2C12 cells, respectively. A dose of 200 mg/kg of ART was orally administered to IR mice, and different doses (25, 50, and 100 μg/ml) of ARTC groups were treated to IR C2C12 cells. IPGTT, IPITT, body weight, Hb1AC, FFA, TNF- α , MCP-1, and IR-associated gene expression (p-AMPK, p-IRS-1, PI3K, p-AKT, p-JNK, and GLUT4) were measured in IR mice. Glucose uptake, TNF- α , MCP-1, and IR-associated gene expression were also measured in IR C2C12 cells. Results showed that ART alleviated high-fat diet-induced IR in the skeletal muscle of mice, and this finding was further validated by ARTC. This study demonstrated that ART presented a notable IR alleviating effect by regulating IR-associated gene expression, and triterpenes were the material basis for the IR alleviating activity of AR.


2019 ◽  
Vol 12 (4) ◽  
pp. 277-290 ◽  
Author(s):  
Mingxia Zhao ◽  
Lihong Shen ◽  
Zijun Ouyang ◽  
Manru Li ◽  
Guoliang Deng ◽  
...  

Abstract Impairment of glucose (Glu) uptake and storage by skeletal muscle is a prime risk factor for the development of metabolic diseases. Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is a highly abundant RNA-binding protein that has been implicated in diverse cellular functions. The aim of this study was to investigate the function of hnRNP A1 on muscle tissue insulin sensitivity and systemic Glu homeostasis. Our results showed that conditional deletion of hnRNP A1 in the muscle gave rise to a severe insulin resistance phenotype in mice fed a high-fat diet (HFD). Conditional knockout mice fed a HFD showed exacerbated obesity, insulin resistance, and hepatic steatosis. In vitro interference of hnRNP A1 in C2C12 myotubes impaired insulin signal transduction and inhibited Glu uptake, whereas hnRNP A1 overexpression in C2C12 myotubes protected against insulin resistance induced by supraphysiological concentrations of insulin. The expression and stability of glycogen synthase (gys1) mRNA were also decreased in the absence of hnRNP A1. Mechanistically, hnRNP A1 interacted with gys1 and stabilized its mRNA, thereby promoting glycogen synthesis and maintaining the insulin sensitivity in muscle tissue. Taken together, our findings are the first to show that reduced expression of hnRNP A1 in skeletal muscle affects the metabolic properties and systemic insulin sensitivity by inhibiting glycogen synthesis.


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