Mechanisms Mediating Anti-Inflammatory Effects of Delta-Tocotrienol and Tart Cherry Anthocyanins in 3T3-L1 Adipocytes

Abstract

Chronic low-grade inflammation is a primary characteristic of obesity and can lead to other metabolic complications including insulin resistance and type 2 diabetes (T2D). Several anti-inflammatory dietary bioactives decrease inflammation that accompanies metabolic diseases. We are specifically interested in delta-tocotrienol, (DT3) an isomer of vitamin E, and tart cherry anthocyanins (TCA), both of which possess individual anti-inflammatory properties. We have previously demonstrated that DT3 and TCA, individually, reduced systemic and adipose tissue inflammation in rodent models of obesity. However, whether these compounds have combinatorial effects has not been determined yet. Hence, we hypothesize that a combined treatment of DT3 and TCA will have great effects in reducing inflammation in adipocytes, and that these effects are mediated via the nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB), a major inflammatory transcription factor. We used 3T3-L1 adipocytes and treated them with 1–5 µM doses of DT3 along with tart cherry containing 18–36 µg anthocyanin/mL, to assess effects on inflammation. Neither DT3 nor TCA, nor their combinations had toxic effects on adipocytes. Furthermore, pro-inflammatory markers interleukin-6 (IL-6) and p-65 (subunit of NFkB) were reduced at the protein level in media collected from adipocytes with both individual and combined treatments. Additionally, other downstream targets of NFkB including macrophage inflammatory protein 2 (Mip2), and Cyclooxygenase-2 (Cox2) were also significantly downregulated (p ≤ 0.05) when treated with individual and combined doses of DT3 and TCA with no additional combinatorial effects. In summary, DT3 and TCA individually, are beneficial in reducing inflammation with no additional combinatorial effects.

Dysfunction of the Brown Adipose Organ in HFD-Obese Rats and Effect of Tart Cherry Supplementation

“…This explains our WB and IHC results, which demonstrated a significant enhancement of IL-6 expression in the DIO and DS groups compared to CHOW rats. In contrast, a restored level of IL-6 was found in the groups that received tart cherry juice fruits, confirming the positive role of these supplements against obesity-induced inflammation [68,69]. Seymour and co-workers [70] reported, in obesity-prone rats fed with an HFD, that the intake of tart cherries reduced retroperitoneal IL-6 and TNF-α mRNA expression, Nuclear factor kappa B (NF-κB) activity, and plasma IL-6 and TNF-α concentrations.…”

Effects of co-incubation of LPS-stimulated RAW 264.7 macrophages on leptin production by 3T3-L1 adipocytes: a method for co-incubating distinct adipose tissue cell lines

“…Despite the differences in NO measured between transwells and wells, IL-6 levels in cell-conditioned media collected from these two compartments were similar. Adipocytes produce IL-6 under the action of LPS (Chirumbolo et al 2014 ; Harlan et al 2020 ), but it is unlikely that the lack of difference in IL-6 levels between the transwells and wells is due to adipocyte-secreted IL-6, since the control experiments showed that LPS-challenged adipocytes produced about a sixth the amount of IL-6 under the action of LPS compared to macrophages (RAW: 1371.8 ± 682.9; 3T3: 225.9 ± 73.4 pg/ml; Fig. 1 b).…”

Germinated Rice Seeds Improved Resveratrol Production to Suppress Adipogenic and Inflammatory Molecules in 3T3-L1 Adipocytes

“…The production of proinflammatory cytokines by adipocyte hypertrophy and hyperplasia led to adipocyte tissue inflammation [26]. The inhibition of the NF-κB and ERK signaling pathways causes a reduction in adipocyte inflammation [27]. Therefore, the bioactive compounds that reduce adipogenic and obesity-induced inflammation are being searched for.…”