Establishment of anIn Vitro screening model for neurodegeneration induced by antimalarial drugs of the artemisinin-type

Abstract

The establishment of an in vitro screening model for neurodegeneration inducing antimalarial drugs was conducted in stepwise fashion. Firstly, the in vivo selective neurotoxic potency of artemisinin was tested in neuronal cells in vitro in relation to the cytotoxic potency in other organ cell cultures such as liver and kidney or versus glial cells. Secondly, a comparison between different parts of the brain (cortex vs. brain stem) was performed and in the last step, a fast and sensitive screening endpoint was identified. In summary, non-neuronal cell lines such as hepatocytes (HEP-G2), liver epithelial cells (IAR), proximal tubular cells (LLC-PK(1)) and glial cells from the rat (C6) and human (GO-G-IJKT) displayed only moderate sensitivity to artemisinin and its derivatives. The same was found in undifferentiated neuronal cell lines from the mouse (N-18) and from human (Kelly), whereas during differentiation, these cells became much more sensitive. Primary astrocytes from the rat also were not specifically involved. In the comparison of primary neuronal cell cultures from the cortex and brain stem of the rat, the brain stem was found to be more sensitive than the cortex. The neurotoxic potential was determined by cytoskeleton elements (neurofilaments), which were degradated in vitro by diverse neurodegenerative compounds. In comparison of dog and rat primary brain stem cultures, the dog cells were found to be more sensitive to artemisinin than the rat cells. In addition to the primary brain stem cell cultures it was shown that the sprouting assay, which determines persistent delayed neurotoxic effects, is also useful for screening antimalarial drugs. To other compounds, artemether and artesunate, showed that use of the sprouting assay followed by primary brain stem cultures of the rat will be a good strategy to select candidate compounds.

Dihydroartemisinin increases temozolomide efficacy in glioma cells by inducing autophagy

“…Previous studies have revealed that artemisinin is able to inhibit the progression of chronic myelogenous leukemia, pancreatic adenocarcinoma, colon cancer, prostate cancer, non-small cell lung cancer and breast malignancies at low concentrations (8)(9)(10). Artemisinin and its derivatives have also been used in the screening of anticancer drugs by the National Cancer Institute (NCI) (11).…”

Neurotoxic Mode of Action of Artemisinin

“…Catalase and GPx convert H 2 O 2 to H 2 O, and the superoxide dismutases (SODs) catalyze the dismutation of the superoxide radical anion. The expression of AOE can be regulated by oxidative stress itself (32,37,39,43), which could also be shown for, among others, astroglial cell cultures (34). It has been demonstrated that primary neuronal cell culture systems are suitable for detection of oxidative stress evoked by paraquat using specific endpoints such as ROS production, lipid peroxidation, and AOE expression (38).…”

“…Recently, we described a new in vitro screening method using primary brain stem cell cultures from the rat (37). We demonstrated that the brain stem cells were selectively sensitive against artemisinin, in contrast to cells from other brain regions, such as the cortex.…”

Alterations in Antioxidant Status and Biochemical Indices Following Administration of Dihydroartemisinin-Piperaquine Phosphate (P-ALAXIN® )

“…Besides scavenger molecules such as glutathione vitamin C, or α-tocopherol, specific enzymes, the antioxidants enzymes (AOE) fulfil this task. The expression of AOE can be regulated by oxidative stress itself [63,64,6,65].Our data indicates that the therapeutic and double therapeutic dose of P-ALAXIN ® affects both enzymatic and nonenzymatic antioxidants.The antioxidant enzymes Catalase and SOD are part of the primary intracellular antioxidants defence mechanism against oxidative stress [28].The decreased activities of SOD and CAT in the liver of the animals treated with the two doses of P ALAXIN ® could be due to the organ's response to an…”