Yajun Yang

Lycorine reduces mortality of human enterovirus 71-infected mice by inhibiting virus replication

Human enterovirus 71 (EV71) infection causes hand, foot and mouth disease in children under 6 years old and this infection occasionally induces severe neurological complications. No vaccines or drugs are clinical available to control EV71 epidemics. In present study, we show that treatment with lycorine reduced the viral cytopathic effect (CPE) on rhabdomyosarcoma (RD) cells by inhibiting virus replication. Analysis of this inhibitory effect of lycorine on viral proteins synthesis suggests that lycorine blocks the elongation of the viral polyprotein during translation. Lycorine treatment of mice challenged with a lethal dose of EV71 resulted in reduction of mortality, clinical scores and pathological changes in the muscles of mice, which were achieved through inhibition of viral replication. When mice were infected with a moderate dose of EV71, lycorine treatment was able to protect them from paralysis. Lycorine may be a potential drug candidate for the clinical treatment of EV71-infected patients.

Naringin Enhances CaMKII Activity and Improves Long-Term Memory in a Mouse Model of Alzheimer's Disease

The Amyloid-β (Aβ)-induced impairment of hippocampal synaptic plasticity is an underlying mechanism of memory loss in the early stages of Alzheimer’s disease (AD) in human and mouse models. The inhibition of the calcium/calmodulin-dependent protein kinase II (CaMKII) autophosphorylation plays an important role in long-term memory. In this study, we isolated naringin from Pomelo peel (a Citrus species) and studied its effect on long-term memory in the APPswe/PS1dE9 transgenic mouse model of AD. Three-month-old APPswe/PS1dE9 transgenic mice were randomly assigned to a vehicle group, two naringin (either 50 or 100 mg/kg body weight/day) groups, or an Aricept (2 mg/kg body weight/day) group. After 16 weeks of treatment, we observed that treatment with naringin (100 mg/kg body weight/day) enhanced the autophosphorylation of CaMKII, increased the phosphorylation of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA) receptor at a CaMKII-dependent site and improved long-term learning and memory ability. These findings suggest that the increase in CaMKII activity may be one of the mechanisms by which naringin improves long-term cognitive function in the APPswe/PS1dE9 transgenic mouse model of AD.

Antiviral Effect of Matrine against Human Enterovirus 71

Human enterovirus 71, a member of the Picornaviridae family, is one of the major causative agent of hand, foot and mouth disease in children less than six years old. This illness has caused mortalities in large-scale outbreaks in the Asia-Pacific region in recent years. No vaccine or antiviral therapy is available. In this study, antiviral effect of matrine against enterovirus 71 were evaluated in vitro and in vivo. Matrine could suppress the viral RNA copy number on rhabdomyosarcoma cells. Moreover, matrine treatment of mice challenged with a lethal dose of enterovirus 71 reduced the mortality and relieved clinical symptoms. The results showed that matrine may represent a potential therapeutic agent for enterovirus 71 infection.

Antiviral effect of geraniin on human enterovirus 71 in vitro and in vivo

Human enterovirus 71 infection causes hand, foot and mouth disease in children under 6 years of age and has caused mortalities in large-scale outbreaks in the Asia-Pacific region. No effective vaccine or antiviral drugs currently exist against enterovirus 71 in the clinic. In this study, we investigated the antiviral effect of geraniin on enterovirus 71 both in vitro and in vivo. The results showed that geraniin effectively inhibited virus replication in rhabdomyosarcoma cells with an IC(50) of 10 μg/ml. Moreover, geraniin treatment of mice that were challenged with a lethal dose of enterovirus 71 resulted in a reduction of mortality, relieved clinical symptoms, and inhibited virus replication in muscle tissues. The results suggest that geraniin may be used as a potential drug for anti-enterovirus 71.

Antiviral activity of punicalagin toward human enterovirus 71 in vitro and in vivo.

Human enterovirus 71 is one of the major causative agents of hand, foot and mouth disease in children and has caused mortalities in large-scale outbreaks in the Asia-Pacific region in recent years. No vaccine or antiviral therapy is available currently in the clinic. In this work, we investigated the antiviral effect of punicalagin on enterovirus 71 both in vitro and in vivo. The results showed that punicalagin reduced the viral cytopathic effect on rhabdomyosarcoma cells with an IC₅₀) value of 15 μg/ml. Moreover, punicalagin treatment of mice challenged with a lethal dose of enterovirus 71 resulted in a reduction of mortality and relieved clinical symptoms by inhibiting viral replication. Our work suggested that punicalagin have the potential for further development as antiviral agents against enterovirus 71.

Chebulagic acid, a hydrolyzable tannin, exhibited antiviral activity in vitro and in vivo against human enterovirus 71.

Human enterovirus 71 is one of the major causative agents of hand, foot and mouth disease in children under six years of age. Presently, no vaccines or antiviral drugs have been clinically available to employ against EV71. In this study, we demonstrate that treatment with chebulagic acid reduced the viral cytopathic effect on rhabdomyosarcoma cells with an IC50 of 12.5 μg/mL. The utilization of the chebulagic acid treatment on mice challenged with a lethal dose of enterovirus 71 was able to efficiently reduce mortality and relieve clinical symptoms through the inhibition of viral replication. Chebulagic acid may represent a potential therapeutic agent to control infections to enterovirus 71.

The effect of PN-1, a Traditional Chinese Prescription, on the Learning and Memory in a Transgenic Mouse Model of Alzheimer’s Disease

Traditional Chinese Medicine (TCM) is a complete medical system that has been practiced for more than 3000 years. Prescription number 1 (PN-1) consists of several Chinese medicines and is designed according to TCM theories to treat patients with neuropsychiatric disorders. The evidence of clinical practice suggests the benefit effects of PN-1 on cognitive deficits of dementia patients. We try to prove and explain this by using contemporary methodology and transgenic animal models of Alzheimers disease (AD). The behavioral studies were developed to evaluate the memory of transgenic animals after intragastric administration of PN-1 for 3 months. Amyloid beta-protein (Aβ) neuropathology was quantified using immunohistochemistry and ELISA. The western blotting was used to detect the levels of plasticity associated proteins. The safety of PN-1 on mice was also assessed through multiple parameters. Results showed that PN-1 could effectively relieve learning and memory impairment of transgenic animals. Possible mechanisms showed that PN-1 could significantly reduce plaque burden and Aβ levels and boost synaptic plasticity. Our observations showed that PN-1 could improve learning and memory ability through multiple mechanisms without detectable side effects on mice. We propose that PN-1 is a promising alternative treatment for AD in the future.

Quinolizidine alkaloids reduced mortality in EV71-infected mice by compensating for the levels of T cells.

Recent outbreak of hand, foot and mouse disease caused by enterovirus 71 is a serious threat to infants and children in Asia-Pacific countries. No vaccines or antiviral therapies are available against this infection. In this study, we found that quinolizidine alkaloids could improve the levels of T cells in mice. The structure-activity relationships demonstrated that the oxidation and double bonds are important for the excellent potency. Oxysophocarpine, the most effective compound of six quinolizidine alkaloids, could also relieve symptoms and reduce mortality in lethal enterovirus 71-infected mice through compensating for the decreased levels of T cells. This work suggested that quinolizidine alkaloids have the potential against enterovirus 71 for further development of novel antiviral drugs.

Deferoxamine compensates for decreases in B cell counts and reduces mortality in enterovirus 71-infected mice.

Enterovirus 71 is one of the major causative agents of hand, foot and mouth disease in children under six years of age. No vaccine or antiviral therapy is currently available. In this work, we found that the number of B cells was reduced in enterovirus 71-infected mice. Deferoxamine, a marine microbial natural product, compensated for the decreased levels of B cells caused by enterovirus 71 infection. The neutralizing antibody titer was also improved after deferoxamine treatment. Furthermore, deferoxamine relieved symptoms and reduced mortality and muscle damage caused by enterovirus 71 infection. This work suggested that deferoxamine has the potential for further development as a B cell-immunomodulator against enterovirus 71.

Rehmannia glutinosa exhibits anti-aging effect through maintaining the quiescence and decreasing the senescence of hematopoietic stem cells

The time‐related decline in regenerative capacity and organ homeostasis is a major feature of aging. Rehmannia glutinosa and Astragalus membranaceus have been used as traditional Chinese herbal medicines for enhanced immunity and prolonged life. However, the mechanism by which this herbal medicine slows aging is unknown. In this study, we investigated the mechanism of the herbal anti‐aging effect.