The Mulberry (Morus alba L.) fruit is a rich source of polyphenolic compounds; most of these are anthocyanins. Obesity is intimately related to low-grade inflammation, with increased pro-inflam-matory cytokine secretion and macrophage infiltration in white adipose tissue (WAT). This study in-vestigated whether mulberry fruit extract (ME) has beneficial effects on obesity-induced inflammation and skeletal muscle mitochondrial dysfunction. Sprague-Dawley rats were divided into four groups and fed either a low-fat diet (LFD), high-fat diet (HFD), HFD + 5 g/kg of ME (ME-L), or HFD + 10 g/kg of ME (ME-H) for 14 weeks. ME alleviated dyslipidemia and lipid accumulation, as well as pro-in-flammatory cytokine production such as tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and mon-ocyte chemoattractant protein 1 (MCP1) in the WAT. ME mitigated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) phosphorylation and macrophage infiltration in WAT. Notably, microRNA (miR)-21, miR-132, and miR-43 expressions were downregulated in the WAT of the ME groups compared to the HFD group. Moreover, ME increased the mitochondrial size and mitochondrial DNA (mtDNA) content, as well as key genes’ expression related to mitochondrial function, including sirtuin (SIRT)1, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), carnitine pal-mitoyltransferase 1β (CPT-1β), and uncoupling protein 3 (UCP3), and adenosine monophosphate-ac-tivated protein kinase (AMPK)/SIRT activities in skeletal muscle. These results suggested that ME might alleviate obesity-induced inflammation and mitochondrial dysfunction by regulating miR-21, miR-132, and miR-43 expression in WAT, and by activating the PGC-1α/SIRT1 pathway in mus-cle.
Bibliographical noteFunding Information:
Funding: This work was supported by the National Research Foundation of Korea (NRF), grant funded by the Korean government (MSIT) (2016R1A2B4011021 and 2019R1A2C1002861), and by Brain Korea 21 Four of the National Research Foundation, funded by the Ministry of Education of Korea.
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- High-fat diet
- Mulberry fruit
- Skeletal muscle mitochondria