Recent studies focused on the pharmacology and feasibility of herbal compounds as a potential strategy to target a variety of human diseases ranging from metabolic to brain disorders. Accordingly, bioactive ingredients which are found within a variety of herbal compounds are reported to produce both neuroprotective and psychotropic activities which may help to combat mental disorders such as depression, anxiety, sleep disturbances and cognitive alterations. In the present manuscript, we focus on three herbs which appear effective in mitigating anxiety or depression with favourable risk-benefit profiles, namely Scutellaria baicalensis (S. baicalensis), Hericium erinaceus (H. erinaceus) and Rhodiola rosea (R. rosea). These three traditional folk medicinal herbs target the main biochemical events that are implicated in mental disorders, mimicking, to some extent, the mechanisms of action of conventional antidepressants and mood stabilizers with a wide margin of tolerability. In detail, they rescue alterations in neurotransmitter and neuro-endocrine systems, stimulate neurogenesis and the synthesis of neurotrophic factors, and they counteract oxidative stress, mitochondrial dysfunction and inflammation. Albeit the encouraging results that emerge from both experimental and clinical evidence, further studies are needed to confirm and better understand the mental-health promoting, and specifically, the antidepressant effects of these herbs.
Recent evidence suggests that autophagy impairment is implicated in the epileptogenic mechanisms downstream of mTOR hyperactivation. This holds true for a variety of genetic and acquired epileptic syndromes besides malformations of cortical development which are classically known as mTORopathies. Autophagy suppression is sufficient to induce epilepsy in experimental models, while rescuing autophagy prevents epileptogenesis, improves behavioral alterations, and provides neuroprotection in seizure-induced neuronal damage. The implication of autophagy in epileptogenesis and maturation phenomena related to seizure activity is supported by evidence indicating that autophagy is involved in the molecular mechanisms which are implicated in epilepsy. In general, mTOR-dependent autophagy regulates the proliferation and migration of inter-/neuronal cortical progenitors, synapse development, vesicular release, synaptic plasticity, and importantly, synaptic clustering of GABAA receptors and subsequent excitatory/inhibitory balance in the brain. Similar to autophagy, the ubiquitin–proteasome system is regulated downstream of mTOR, and it is implicated in epileptogenesis. Thus, mTOR-dependent cell-clearing systems are now taking center stage in the field of epilepsy. In the present review, we discuss such evidence in a variety of seizure-related disorders and models. This is expected to provide a deeper insight into the molecular mechanisms underlying seizure activity.
The triorganotin compound trimethyltin (TMT) is a highly toxic molecule which has a great impact on human health. The aim of this study was to investigate the specific alteration of dopamine receptors and transporters in the hippocampus of TMT-treated rats. The TMT-treated group showed impaired spatial reference memory in a Morris water maze task compared to the control group, whereas memory consolidation tested 24 hours after the last training session was preserved. In the open field, TMT-treated rats showed a decrease in time spent in rearing episodes reflecting a lower interest to explore a novel environment. In the hippocampal area of the TMT-treated group, we observed a reduction in neuronal viability accompanied by a significant decrease in the expression of the dopamine receptors (D1 and D2), and dopamine transporters (DAT, VMAT1 and VMAT2). A less pronounced reduction was observed for D3 and D5 while D4 did not change. These data were confirmed by RT-PCR analysis. The present study on TMT-induced neurodegeneration highlights the link between hippocampal asset of dopamine receptors and transporters and the impaired performance of rats in a spatial reference memory task.
In glioblastoma (GBM) cells, an impairment of mitochondrial activity along with autophagy suppression occurs. Autophagy suppression in GBM promotes stemness, invasion, and poor prognosis. The autophagy deficit seems to be due, at least in part, to an abnormal up-regulation of the mammalian target of rapamycin (mTOR), which may be counteracted by pharmacological mTORC1 inhibition. Since autophagy activation is tightly bound to increased mitochondriogenesis, a defect in the synthesis of novel mitochondria is expected to occur in GBM cells. In an effort to measure a baseline deficit in mitochondria and promote mitochondriogenesis, the present study used two different GBM cell lines, both featuring mTOR hyperactivity. mTORC1 inhibition increases the expression of genes and proteins related to autophagy, mitophagy, and mitochondriogenesis. Autophagy activation was counted by RT-PCR of autophagy genes, LC3- immune-fluorescent puncta and immune-gold, as well as specific mitophagy-dependent BNIP3 stoichiometric increase in situ, within mitochondria. The activation of autophagy-related molecules and organelles after rapamycin exposure occurs concomitantly with progression of autophagosomes towards lysosomes. Remarkably, mitochondrial biogenesis and plasticity (increased mitochondrial number, integrity, and density as well as decreased mitochondrial area) was long- lasting for weeks following rapamycin withdrawal.
The term cholangiocarcinoma (CCA) defines a class of epithelial malignancies originating from bile ducts. Although it has been demonstrated that CCA patients with perineural invasion (PNI) have a worse prognosis, the biological features of this phenomenon are yet unclear. Our data show that in human intrahepatic CCA specimens with documented PNI, nerve-infiltrating CCA cells display positivity of the epithelial marker cytokeratin 7, lower with respect to the rest of the tumor mass. In an in vitro 3D model, CCA cells move towards a peripheral nerve explant allowing contact with Schwann cells (SCs) emerging from the nerve. Here, we show that SCs produce soluble factors that favor the migration, invasion, survival and proliferation of CCA cells in vitro. This effect is accompanied by a cadherin switch, suggestive of an epithelial–mesenchymal transition. The influence of SCs in promoting the ability of CCA cells to migrate and invade the extracellular matrix is hampered by a specific TGFβ receptor 1 (TGFBR1) antagonist. Differential proteomic data indicate that the exposure of CCA cells to SC secreted factors induces the upregulation of key oncogenes and the concomitant downregulation of some tumor suppressors. Taken together, these data concur in identifying SCs as possible promoters of a more aggressive CCA phenotype, ascribing a central role to TGFβ signaling in regulating this process.