Triple herbal extract DA-9805 exerts a neuroprotective effect via amelioration of mitochondrial damage in experimental models of Parkinson's disease.

Moutan cortex, Angelica Dahurica root, and Bupleurum root are traditional herbal medicines used in Asian countries to treat various diseases caused by oxidative stress or inflammation. Parkinson's disease (PD) has been associated with mitochondrial dysfunction, but no effective treatment for mitochondrial dysfunction has yet been identified. In this study we investigated the neuroprotective effects of the triple herbal extract DA-9805 in experimental models of PD. DA-9805 was prepared by extracting three dried plant materials (Moutan cortex, Angelica Dahurica root, and Bupleurum root in a 1:1:1 mixture) with 90% ethanol on a stirring plate for 24 h at room temperature and fingerprinted using high-performance liquid chromatography. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its active metabolite 1-methyl-4-phenylpyridinium (MPP+), which both exert neurotoxic effects on dopaminergic neurons by inhibiting mitochondrial oxidative phosphorylation (OXPHOS) complex I, were used to make experimental models of PD. In MPP+-treated SH-SY5Y cells, DA-9805 ameliorated the suppression of tyrosine hydroxylase expression and mitochondrial damage on OXPHOS complex 1 activity, mitochondrial membrane potential, reactive oxygen species (ROS) generation, and oxygen consumption rate. In the MPTP-induced subacute PD model mice, oral administration of DA-9805 recovered dopamine content as well as bradykinesia, as determined by the rotarod test. DA-9805 protected against neuronal damage in the substantia nigra pars compacta (SNpc) and striatum. In both in vitro and in vivo models of PD, DA-9805 normalized the phosphorylation of AKT at S473 and T308 on the insulin signaling pathway and the expression of mitochondria-related genes. These results demonstrate that the triple herbal extract DA-9805 showed neuroprotective effects via alleviating mitochondria damage in experimental models of PD. We propose that DA-9805 may be a suitable candidate for disease-modifying therapeutics for PD.

Cell-penetrating artificial mitochondria-targeting peptide-conjugated metallothionein 1A alleviates mitochondrial damage in Parkinson's disease models.

An excess of reactive oxygen species (ROS) relative to the antioxidant capacity causes oxidative stress, which plays a role in the development of Parkinson's disease (PD). Because mitochondria are both sites of ROS generation and targets of ROS damage, the delivery of antioxidants to mitochondria might prevent or alleviate PD. To transduce the antioxidant protein human metallothionein 1A (hMT1A) into mitochondria, we computationally designed a cell-penetrating artificial mitochondria-targeting peptide (CAMP). The recombinant CAMP-conjugated hMT1A fusion protein (CAMP-hMT1A) successfully localized to the mitochondria. Treating a cell culture model of PD with CAMP-hMT1A restored tyrosine hydroxylase expression and mitochondrial activity and reduced ROS production. Furthermore, injection of CAMP-hMT1A into the brain of a mouse model of PD rescued movement impairment and dopaminergic neuronal degeneration. CAMP-hMT1A delivery into mitochondria might be therapeutic against PD by alleviating mitochondrial damage, and we predict that CAMP could be used to deliver other cargo proteins to the mitochondria.