Indirubin promotes adipocyte differentiation and reduces lipid accumulation in 3T3‑L1 cells via peroxisome proliferator‑activated receptor γ activation

Indirubin mediates adverse intestinal reactions in guinea pigs by downregulating the expression of AchE through AhR

Indirubin is the main component of the traditional Chinese medicine Indigo naturalis (IN), a potent agonist of aryl hydrocarbon receptors (AhRs). In China, IN is used to treat psoriasis and ulcerative colitis, and indirubin is used for the treatment of chronic myelogenous leukaemia. However, IN and indirubin have adverse reactions, such as abdominal pain, diarrhoea, and intussusception, and their specific mechanism is unclear.The purpose of our research was to determine the specific mechanism underlying the adverse effects of IN and indirubin. By tracking the modifications in guinea pigs after the intragastric administration of indirubin for 28 days.The results demonstrate that indirubin could accelerate bowel movements and decrease intestinal acetylcholinesterase (AchE) expression. Experiments with NCM460 cells revealed that indirubin significantly reduced the expression of AchE, and the AchE levels were increased after the silencing of AhR and re-exposure to indirubin.This study showed that the inhibition of AchE expression by indirubin plays a key role in the occurrence of adverse reactions to indirubin and that the underlying mechanism is related to AhR-mediated AchE downregulation.

LSD1 in beige adipocytes protects cardiomyocytes against oxygen and glucose deprivation

Objectives

Epicardial adipose tissue (EpAT) is known for its role in supporting the cardiomyocytes. Lysine-specific demethylase 1 (LSD1), a typical lysine demethylase, is an essential regulator for the maintenance of beige adipocytes. However, the effect of LSD1 in the adipogenic differentiation of beige adipocytes in EpAT, and its function on oxygen and glucose deprivation (OGD)-injured cardiomyocytes remain unclear.

Materials and Methods

Heart tissues from young mice and elder mice were collected for immunohistochemical staining. LSD1 in 3T3-L1 cells was knocked down by LSD1-shRNA lentivirus infection. The qRT-PCR, western blotting, and Oil Red O staining were employed to detect the adipogenic differentiation of 3T3-L1 cells and formation of beige adipocytes. The cardiomyocytes co-cultured with beige adipocytes were used for OGD treatment. Cell apoptosis was analyzed by flow cytometry. The lactate dehydrogenase (LDH) and superoxide dismutase (SOD) activity were analyzed using commercially available kits.

Results

The decrease of LSD1 was related to the age-dependent loss of beige adipocytes in mice EpAT. LSD1 knockdown inhibited the adipogenic differentiation of 3T3-L1 cells and formation of beige adipocytes. The down-regulation of LSD1 in 3T3-L1 cells decreased the protective effect of mature adipocytes on OGD-injured cardiomyocytes.

Conclusion

The decreased expression of LSD1 in mice EpAT was associated with age-dependent ablation of beige adipocytes. The protective effect of beige adipocytes on OGD-injured cardiomyocytes is reduced by knockdown of LSD1 in adipocytes. The present study provided exciting insights into establishing novel therapies against age-dependent cardiac diseases.

Paeoniflorin, a constituent of Kami-shoyo-san, suppresses blood glucose levels in postmenopausal diabetic mice by promoting the secretion of estradiol from adipocytes

Ovarian functional deterioration in women with climacteric disorders increases the prevalence of type 2 diabetes (T2D). Therefore, we revealed that paeoniflorin (PF), an ingredient of paeony root (PR), which is a constituent of Kami-shoyo-san (KS), promotes glucose uptake by increasing estradiol secretion from adipocytes. Adipocytes differentiated from 3T3-L1 cells were incubated in culture medium containing the extracts of KS, PR, KS excluding PR (KS-PR), or PF for 5 d at 37 °C and 5% CO₂. The estradiol and glucose concentrations in the medium were determined using enzyme-linked immunosorbent assay (ELISA). Next, PF (1 or 10 mg/kg) was subcutaneously injected into ovariectomized mice (12-week-old, ICR strain) once daily for 19 d to perform the glucose tolerance test and determine blood estradiol and adiponectin levels. The release of estradiol from 3T3-L1 adipocytes was significantly increased by KS, PR, KS-PR, and PF, and the increased estradiol level caused by KS was significantly decreased by excluding PF from KS (KS-PR). Glucose concentration in the medium was significantly decreased by KS and PF. In in vivo experiments, the 10 mg/kg PF-treated group showed significantly suppressed blood glucose levels at 0 and 30 min after d-glucose loading by intraperitoneal injection. These findings indicate that KS, which includes PR-containing PF as the main ingredient, may have the potential to prevent T2D caused by ovarian dysfunction in menopausal women by increasing estradiol secretion from adipocytes.

A tunable synthesis of indigoids: targeting indirubin through temperature

The spontaneous conversion of 3-indoxyl to indigo is a well-established process used to produce indigo dyes. It was recently shown that some indoles, when reacted with molybdenum hexacarbonyl and cumyl peroxide, proceed through an indoxyl intermediate to produce significant amounts of indirubin through a competing mechanism. Modulation of this system to lower temperatures allows for careful tuning, leading to selective production of indirubins in a general process. A systematic assay of indoles show that electron deficient indoles work well when substituted at the 5 and 7 positions. In contrast, 6-substituted electron rich indoles give the best results whereas halogeno indoles work well in all cases. This process shows broad functional group tolerance for generally reactive carbonyl-containing compounds such as aldehydes and carboxylic acids.