Catalpol Ameliorates Neurotoxicity in N2a/APP695swe Cells and APP/PS1 Transgenic Mice

Lactate: a prospective target for therapeutic intervention in psychiatric disease

ABSTRACT

Although antipsychotics that act via monoaminergic neurotransmitter modulation have considerable therapeutic effect, they cannot completely relieve clinical symptoms in patients suffering from psychiatric disorders. This may be attributed to the limited range of neurotransmitters that are regulated by psychotropic drugs. Recent findings indicate the need for investigation of psychotropic medications that target less-studied neurotransmitters. Among these candidate neurotransmitters, lactate is developing from being a waste metabolite to a glial-neuronal signaling molecule in recent years. Previous studies have suggested that cerebral lactate levels change considerably in numerous psychiatric illnesses; animal experiments have also shown that the supply of exogenous lactate exerts an antidepressant effect. In this review, we have described how medications targeting newer neurotransmitters offer promise in psychiatric diseases; we have also summarized the advances in the use of lactate (and its corresponding signaling pathways) as a signaling molecule. In addition, we have described the alterations in brain lactate levels in depression, anxiety, bipolar disorder, and schizophrenia and have indicated the challenges that need to be overcome before brain lactate can be used as a therapeutic target in psychopharmacology.

Novel histone post-translational modifications in Alzheimer's disease: current advances and implications

Alzheimer's disease (AD) has a complex pathogenesis, and multiple studies have indicated that histone post-translational modifications, especially acetylation, play a significant role in it. With the development of mass spectrometry and proteomics, an increasing number of novel HPTMs, including lactoylation, crotonylation, β-hydroxybutyrylation, 2-hydroxyisobutyrylation, succinylation, and malonylation, have been identified. These novel HPTMs closely link substance metabolism to gene regulation, and an increasing number of relevant studies on the relationship between novel HPTMs and AD have become available. This review summarizes the current advances and implications of novel HPTMs in AD, providing insight into the deeper pathogenesis of AD and the development of novel drugs.

Catalpol Alleviates Ischemic Stroke Through Promoting Angiogenesis and Facilitating Proliferation and Differentiation of Neural Stem Cells via the VEGF-A/KDR Pathway

Stroke is one of the leading causes of disability and death globally with a lack of effective therapeutic strategies. Catalpol is a bioactive compound derived from the traditional Chinese medicine Rehmannia glutinosa and it has been shown to be protective against various neurological diseases. The potential roles of catalpol against ischemic stroke are still not completely clear. In this study, we examined the effect and mechanism of catalpol against ischemic stroke using in vivo rat distal middle cerebral artery occlusion (dMCAO) and in vitro oxygen-glucose deprivation (OGD) models. We demonstrated that catalpol indeed attenuated the neurological deficits caused by dMCAO and improved neurological function. Catalpol remarkably promoted angiogenesis, promoted proliferation and differentiation of neural stem cells (NSCs) in the subventricular zone (SVZ), and prevented neuronal loss and astrocyte activation in the ischemic cortex or hippocampal dentate gyrus (DG) in vivo. The vascular endothelial growth factor receptor 2 (KDR, VEGFR-2) inhibitor SU5416 and VEGF-A shRNA were used to investigate the underlying mechanisms. The results showed that SU5416 administration or VEGF-A-shRNA transfection both attenuated the effects of catalpol. We also found that catalpol promoted the proliferation of cultured brain microvascular endothelial cells (BMECs) and the proliferation and differentiation of NSCs subjected to OGD insult in vitro. Interestingly, the impact of catalpol on cultured cells was also inhibited by SU5416. Moreover, catalpol was shown to protect NSCs against OGD indirectly by promoting BMEC proliferation in the co-cultured system. Taken together, catalpol showed therapeutic potential in cerebral ischemia by promoting angiogenesis and NSC proliferation and differentiation. The protective effects of catalpol were mediated through VEGF-A/KDR pathway activation.

Lactate-induced protein lactylation: A bridge between epigenetics and metabolic reprogramming in cancer

Lactate is not only an endpoint of glycolysis but is gradually being discovered to play the role of a universal metabolic fuel for energy via the 'lactate shuttle' moving between cells and transmitting signals. The glycolytic-dependent metabolism found in tumours and fast-growing cells has made lactate a pivotal player in energy metabolism reprogramming, which enables cells to obtain abundant energy in a short time. Moreover, lactate can provide favourable conditions for tumorigenesis by shaping the acidic tumour microenvironment, recruiting immune cells, etc. and the recently discovered lactate-induced lactylation moves even further on pro-tumorigenesis mechanisms of lactate production, circulation and utilization. As with other epigenetic modifications, lactylation can modify histone proteins to alter the spatial configuration of chromatin, affect DNA accessibility and regulate the expression of corresponding genes. What's more, the degree of lactylation is inseparable from the spatialized lactate concentration, which builds a bridge between epigenetics and metabolic reprogramming. Here, we review the important role of lactate in energy reprogramming, summarize the latest finding of lactylation in tumorigenesis and try to explore therapeutic strategies in oncotherapy that can kill two birds with one stone.

Catalpol rescues cognitive deficits by attenuating amyloid β plaques and neuroinflammation

This study sought to investigate the anti-amyloid β (Aβ) and anti-neuroinflammatory effects of catalpol in an Alzheimer's disease (AD) mouse model.

METHODS

The effects of catalpol on Aβ formation were investigated by thioflavin T assay. The effect of catalpol on generating inflammatory cytokines from microglial cells and the cytotoxicity of microglial cells on HT22 hippocampal cells were assessed by real-time quantitative PCR, ELISA, redox reactions, and cell viability. APPswe/PS1ΔE9 mice were treated with catalpol, and their cognitive ability was investigated using the water maze and novel object recognition tests. Immunohistochemistry and immunofluorescence were used to probe for protein markers of microglia and astrocyte, Aβ deposits, and NF-κB pathway activity. Aβ peptides, neuroinflammation, and nitric oxide production were examined using ELISA and redox reactions.

RESULTS

Catalpol potently inhibited Aβ fibril and oligomer formation. In microglial cells stimulated by Aβ, catalpol alleviated the expression of the proinflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and inducible nitric oxide synthase (iNOS) but promoted the expression of the anti-inflammatory cytokine IL-10. Catalpol alleviated the cytotoxic effects of Aβ-exposed microglia on HT22 cells. Treatment with catalpol in APPswe/PS1ΔE9 mice downregulated neuroinflammation production, decreased Aβ deposits in the brains and alleviated cognitive impairment. Catalpol treatment decreased the number of IBA-positive microglia and GFAP-positive astrocytes and their activities of the NF-κB pathway in the hippocampus of APPswe/PS1ΔE9 mice.

CONCLUSION

The administration of catalpol protected neurons by preventing neuroinflammation and Aβ deposits in an AD mouse model. Therefore, catalpol may be a promising strategy for treating AD.