Suppression of Nrf2 attenuates adipogenesis and decreases FGF21 expression through PPAR gamma in 3T3-L1 cells.

Adipogenesis is the process of differentiation from preadipocytes to adipocytes and is orchestrated by various transcription factors, such as the peroxisome proliferator-activated receptor gamma (PPARγ) and the CCAAT-enhancer-binding protein alpha (C/EBPα). Oxidative stress is also a crucial factor in adipogenesis, and adipocyte differentiation is affected by the cellular redox status. The nuclear factor E2-related factor 2 (Nrf2), which is a basic leucine zipper (bZIP) transcription factor, acts as a regulator of cellular oxidative stress. Although several previous studies examined the function of Nrf2 in adipogenesis, their results were controversial. In this study, we investigated whether the suppression of Nrf2 in 3T3-L1 cells affected adipogenesis. We found that adipogenesis master regulator genes, such as PPARγ and C/EBPα, were downregulated during the differentiation stage in Nrf2-knockdown 3T3-L1 cells. Moreover, the fibroblast growth factor 21 (FGF21) and manganese superoxide dismutase (MnSOD) were markedly downregulated in Nrf2-knockdown 3T3-L1 cells. Taken together, the results of the present study suggest that the suppression of Nrf2 attenuates adipogenesis and decreases FGF21 expression through PPARγ in 3T3-L1 cells.

Comparison of Tobacco Use and Cessation Behavior between Conventional Cigarette and Heated Tobacco Product Users: Based on the Analyses of the Eighth Korea National Health and Nutrition Examination Survey 2019.

BACKGROUND: After the advent of heated tobacco products (HTPs) in 2017, domestic cigarette sales declined until 2019, but have increased in South Korea since 2020. This study aimed to analyze tobacco use and cessation behavior among HTP users compared with conventional cigarette (CC) users. METHODS: We analyzed data from the eighth Korea National Health and Nutrition Examination Survey (2019). Of 6,188 study participants, 1,181 were current tobacco product users (single, dual, and triple), including all combinations of CCs, HTPs, and electronic cigarettes (ECs). Tobacco use and cessation behaviors among single and dual users of CCs and HTPs were assessed using various categorical methods. RESULTS: In 2019, proportions of HTP use in men and women aged ≥19 years in South Korea were 8.8% and 1.5%, respectively, and those of single, dual, and triple users were 23.6%, 58.0%, and 18.4%, respectively. Dual users had more tobacco use than CC only and HTP only users (all P<0.001). Each daily user accounted for a lower percentage of attempt and preparation stages for cessation than intermittent users (all P<0.001, except for dual users). CONCLUSION: In this study, we analyzed the differences in tobacco use and cessation behavior among CC and HTP users in various populations in South Korea. Additionally, we found that all novel tobacco product users had already experienced CCs in adulthood. Further studies that address HTP's harmful effects in humans are necessary.