Euptox A Induces G1 Arrest and Autophagy via p38 MAPK- and PI3K/Akt/mTOR-Mediated Pathways in Mouse Splenocytes

Abstract

Euptox A (9-oxo-10, 11-dehydroageraphorone), the main toxin isolated from Eupatorium adenophorum, is known to induce immunotoxicity in animals. However, the precise mechanism underlying the effects of Euptox A on splenocytes is unclear. Here, we aimed to investigate the molecular mechanisms underlying the effect of Euptox A in mouse spleens after its intragastric administration and found that Euptox A exhibits proautophagic effects in splenocytes. Euptox A markedly arrested the splenocytes in the G0/G1 phase, which was accompanied by inhibition of the expression of the positive regulators CDK4, CDK2, cyclin D1, PCNA, and E2F1, and promotion of the expression of the negative regulators p53, p21 Waf1/Cip1, p27 Kip1, and Chk1. We also found that Euptox A did not markedly induce splenocyte apoptosis, but induced autophagy while increasing the subcellular localization of punctate LC3, ratio of LC3-II/LC3-I, and Beclin 1 levels, and decreasing p62 levels. Euptox A also significantly inhibited p-PI3K, p-p38 MAPK, p-Akt, and p-mTOR expression, but increased PTEN and p-AMPK expression. These results indicated that Euptox A induced splenocyte autophagy by inhibiting the PI3K/Akt/mTOR pathway, suppressing p38 MAPK expression, and activating AMPK. These findings provide new insights into the mechanisms involved in spleen toxicity caused by Euptox A in mice.

Ageratina adenophora Inhibits Spleen Immune Function in Rats via the Loss of the FRC Network and Th1–Th2 Cell Ratio Elevation

“…Based on the toxicology literature, it would seem plausible these sesquiterpenes could be possible causative agents for the splenic immunomodulatory effects noted here. A study by Mo et al [ 17 ] stated that Euptox A induced G 1 arrest and autophagy among the splenocytes of mice who had ingested the toxin. Ouyang et al [ 16 ] specifically reported that both DAOA and OA caused alterations in the histopathology of the spleens of mice that had been exposed to these toxic compounds.…”

“…Among the effects reported are abnormal liver hematology, jaundice, hepatocyte necrosis, bile duct hyperplasia, liver oxidative stress, and inflammation [ 13 , 14 , 15 ]. Other studies have also reported toxicity in the spleen, with characteristics like abnormal spleen cell proliferation, increased apoptosis, and tissue oxidative stress damage [ 16 , 17 , 18 ]. However, A. adenophora also have ethno-pharmacological uses, such as anti-malaria, anti-inflammation, analgesic, and wound healing [ 19 ].…”

“…Meanwhile, Okyere et al [ 24 ] reported that ODA (Euptox A) caused apoptosis and G 0 /G 1 cell arrest of hepatocytes via an induced accumulation of reactive oxygen species (ROS). Mo et al [ 17 ] reported that ODA induced G 1 arrest and autophagy in mouse splenocytes through p38 MAPK- and PI3K/Akt/mTOR- mediated pathways. Nevertheless, other potentially toxic substances in A. adenophora have not been studied fully for their general toxicity, or their immunotoxic potentials in particular.…”

An Overview: The Toxicity of Ageratina adenophora on Animals and Its Possible Interventions

“…These toxins are mainly found in the leaves with a mass percentage of 0.63–1.99 % in dry leaves [ 28 ]. 9-Oxo-10, 11-dehydro-agerophorone (euptox A) exhibited hepatotoxicity in rodents [ 7 , 29 , 30 , 31 ] with a median lethal dose (LD50) of 1470 mg/kg body weight of mice, whereas 2-deoxo-2-(acetyloxy)-9-oxo-ageraphorone(DAOA) and 9-oxo-agerophorone (OA) also showed hepatotoxicity in mice with respective LD50 of 926 mg/kg BW and 1470 mg/kg BW [ 27 ]. DAOA and euptox A are also immunotoxic to mice, showing characteristics such as reduction in numbers and irregular arrangement of splenocytes and thymocytes [ 13 ].…”

Ageratina adenophora Disrupts the Intestinal Structure and Immune Barrier Integrity in Rats

“…A current study by Okyere et al [ 15 ] reported that ODA caused apoptosis and G0/G1 cell arrest of hepatocytes in mice. In addition, in mouse splenocytes, ODA induced G1 arrest and autophagy [ 16 ].…”