Antiatherosclerotic Effect of Korean Red Ginseng Extract Involves Regulator of G‐Protein Signaling 5

Abstract

Regulator of G-protein signaling 5 (RGS5), an inhibitor of Gα(q) and Gα(i) activation, has been reported to have antiatherosclerosis. Previous studies showed antiatherosclerotic effect of Korean red ginseng water extract (KRGE) via multiple signaling pathways. However, potential protective effect of KRGE through RGS5 expression has not been elucidated. Here, we investigated the antiatherosclerotic effect of KRGE in vivo and in vitro and its role on RGS5 mRNA expression. Elevated levels of total cholesterol, lactate dehydrogenase (LDH), and triglyceride (TG) in western diet groups of low-density lipoprotein receptor deficient LDLr−/− mice were reversed by oral administration of KRGE. KRGE suppressed transcriptional activity of tumor necrotic factor alpha (TNF-α), interleukin-6 (IL-6), and leptin in adipose tissue. It also potently repressed western diet-induced atheroma formation in aortic sinus. While KRGE showed reduced mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), IL-1β, IL-6, and TNF-α in LPS-stimulated RAW264.7 cells, it enhanced mRNA expression of RGS5. Moreover, RGS5 siRNA transfection of microglia cells pretreated with KRGE reversed its inhibitory effect on the expression of iNOS, COX-2, and IL-1β mRNA. In conclusion, KRGE showed antiatherosclerotic and anti-inflammatory effects in western diet fed LDLr−/− mice and this effect could partly be mediated by RGS5 expression.

Black ginseng extract ameliorates hypercholesterolemia in rats

“…For the mRNA expression of ACAT2, SERBP2, and HMG-CoA, total RNA was extracted from the liver tissues using TRIzol reagent (Invitrogen, Carlsbad, CA, USA) following the manufacturer's instructions and as previously described, but with little modifications [10] . In brief, 1 mL TRIzol reagent was added to 100 mg of the liver sample and the tissues were homogenized using a power homogenizer.…”

“…The samples were then incubated at room temperature for 5 min to permit complete disassociation of nuclear proteins. The remaining steps were carried out as described previously [10] .…”

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“…Skin photoaging is characterized by an increase in epidermal thickness and wrinkle formation and a decrease in skin elasticity, which is associated with a decrease in collagen content, the principal component of the dermal layer [4,53]. Moreover, epidermal thickness increases in response to UVB exposure for the purpose of preventing further UV damage and carcinogenesis [29,32].…”

Enhanced Rg3 negatively regulates Th1 cell responses

“…Korean Red Ginseng (KRG) is heat-processed White ginseng (the root of Panax ginseng Meyer); it has better pharmacological activities and has enhanced preservation efficacy and safety [1], [2]. Accumulating evidence clearly demonstrates the beneficial effects of KRG extract (KRGE) on enhancing immune functions [3], [4] as well as ameliorating diverse diseases including diabetes [5], [6], colitis [7], [8], cancer [7], [9], atherosclerosis [10], [11], neurodegenerative disease [12], [13], and stress [14].…”