Chunxia Wang1, Chengliang Wang2, Liying Ren3, Shankang Chen3, Wen-Hua Chen4, Yuhao Li5. 1. Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China. Electronic address: wangcx@smu.edu.cn. 2. Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China. 3. Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. 4. Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China. Electronic address: whchen@smu.edu.cn. 5. Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Endocrinology and Metabolism Group, Sydney Institute of Health Sciences/Sydney Institute of Traditional Chinese Medicine, NSW 2000, Australia. Electronic address: yuhao@sitcm.edu.au.
Abstract
AIMS: Skeletal muscle insulin resistance (SMIR) contributes to the metabolic syndrome. Mounting evidence has demonstrated that the second generation antipsychotic olanzapine causes SMIR. The present study sought to investigate the molecular mechanisms underlying olanzapine-induced SMIR. MAIN METHODS: Male rats were given olanzapine (5 mg/kg, by a gavage method) for consecutive eight weeks. Plasma glucose and insulin concentrations were determined enzymatically or by ELISA. Gene/protein expression was analyzed by Real-Time PCR, Western blot and/or immunohistochemistry. KEY FINDINGS: Olanzapine increased fasting plasma insulin concentration, and decreased glucose clearance during insulin tolerance test in rats. In skeletal muscle, it decreased protein expression of membrane glucose transporter (GLUT) 4, the ratio of membrane to total GLUT4, and total insulin receptor substrate 1 (IRS1). However, it increased protein phosphorylation of Ser307 in IRS1, Y607 in phosphoinositide 3-kinase p85α and Ser307 in AKT. These results indicate olanzapine-induced impairment of skeletal muscle insulin signaling. Mechanistically, olanzapine upregulated mRNA expression of TNFα, IL6 and IL1β, and protein phosphorylation of both IκB kinase (IKK)α/β and nuclear factor (NF)κB p65. Furthermore, it increased protein phosphorylation of Ser485/491 in AMPKα2, whereas it decreased AMPKα2 activity. More importantly, both Western blot and immunohistochemical analyses revealed that olanzapine increased protein phosphorylation of Ser744/748 in protein kinase D1 (PKD1). SIGNIFICANCE: The present results suggest that the PKD1-mediated inflammatory pathway is involved in olanzapine-induced impairment of skeletal muscle insulin signaling in rats. Our findings may go new insight into the mechanisms underlying olanzapine-induced SMIR.
AIMS: Skeletal muscle insulin resistance (SMIR) contributes to the metabolic syndrome. Mounting evidence has demonstrated that the second generation antipsychotic olanzapine causes SMIR. The present study sought to investigate the molecular mechanisms underlying olanzapine-induced SMIR. MAIN METHODS: Male rats were given olanzapine (5 mg/kg, by a gavage method) for consecutive eight weeks. Plasma glucose and insulin concentrations were determined enzymatically or by ELISA. Gene/protein expression was analyzed by Real-Time PCR, Western blot and/or immunohistochemistry. KEY FINDINGS:Olanzapine increased fasting plasma insulin concentration, and decreased glucose clearance during insulin tolerance test in rats. In skeletal muscle, it decreased protein expression of membrane glucose transporter (GLUT) 4, the ratio of membrane to total GLUT4, and total insulin receptor substrate 1 (IRS1). However, it increased protein phosphorylation of Ser307 in IRS1, Y607 in phosphoinositide 3-kinase p85α and Ser307 in AKT. These results indicate olanzapine-induced impairment of skeletal muscle insulin signaling. Mechanistically, olanzapine upregulated mRNA expression of TNFα, IL6 and IL1β, and protein phosphorylation of both IκB kinase (IKK)α/β and nuclear factor (NF)κB p65. Furthermore, it increased protein phosphorylation of Ser485/491 in AMPKα2, whereas it decreased AMPKα2 activity. More importantly, both Western blot and immunohistochemical analyses revealed that olanzapine increased protein phosphorylation of Ser744/748 in protein kinase D1 (PKD1). SIGNIFICANCE: The present results suggest that the PKD1-mediated inflammatory pathway is involved in olanzapine-induced impairment of skeletal muscle insulin signaling in rats. Our findings may go new insight into the mechanisms underlying olanzapine-induced SMIR.
Authors: Andrea Del Campo; Catalina Salamanca; Angelo Fajardo; Francisco Díaz-Castro; Catalina Bustos; Camila Calfío; Rodrigo Troncoso; Edgar R Pastene-Navarrete; Claudio Acuna-Castillo; Luis A Milla; Carlos A Villarroel; Francisco A Cubillos; Mario Aranda; Leonel E Rojo Journal: Molecules Date: 2021-10-12 Impact factor: 4.411