Rolipram Ameliorates Memory Deficits and Depression-Like Behavior in APP/PS1/tau Triple Transgenic Mice: Involvement of Neuroinflammation and Apoptosis via cAMP Signaling

Rationality of the ethanol precipitation process in modern preparation production of Zishui-Qinggan decoction evaluated by integrating UPLC-QTOF-MS/MS-based chemical profiling/serum pharmacochemistry and network pharmacology

INTRODUCTION

Zishui-Qinggan decoction (ZQD) is a classical traditional Chinese medicine formula (TCMF) for alleviating menopausal symptoms (MPS) induced by endocrine therapy in breast cancer patients. In the production of TCMF modern preparations, ethanol precipitation (EP) is a commonly but not fully verified refining process.

OBJECTIVES

Chemical profiling/serum pharmacochemistry and network pharmacology approaches were integrated for exploring the rationality of the EP process in the production of ZQD modern preparations.

MATERIAL AND METHODS

Ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) was applied to identify the chemical profiles and absorbed components of ZQD. Network pharmacology was used to identify targets and pathways related to MPS-relieving efficacy.

RESULTS

The chemicals of ZQDs without/with EP process (referred to as ZQD-W and ZQD-W-P, respectively) were qualitatively similar with 89 and 87 components identified, respectively, but their relative contents were different; 51 components were detectable in the serum of rats orally administered with ZQD-W, whereas only 19 were detected in that administered with ZQD-W-P. Key targets, such as AKT1, and pathways, such as the PI3K-Akt signalling pathway, affected by ZQD-W and ZQD-W-P were similar, while the neuroactive ligand-receptor interaction pathway among others and the MAPK signalling pathway among others were specific pathways affected by ZQD-W and ZQD-W-P, respectively. The specifically absorbed components of ZQD-W could combine its specific key targets.

CONCLUSION

The EP process quantitatively altered the chemical profiles of ZQD, subsequently affected the absorbed components of ZQD, and then affected the key targets and pathways of ZQD for relieving MPS. The EP process might result in variation of the MPS-relieving efficacy of ZQD, which deserves further in vivo verification.

Phosphodiesterase 8 (PDE8): Distribution and Cellular Expression and Association with Alzheimer's Disease

Phosphodiesterase 8 (PDE8), as a member of PDE superfamily, specifically promotes the hydrolysis and degradation of intracellular cyclic adenosine monophosphate (cAMP), which may be associated with pathogenesis of Alzheimer's disease (AD). However, little is currently known about potential role in the central nervous system (CNS). Here we investigated the distribution and expression of PDE8 in brain of mouse, which we believe can provide evidence for studying the role of PDE8 in CNS and the relationship between PDE8 and AD. Here, C57BL/6J mice were used to observe the distribution patterns of two subtypes of PDE8, PDE8A and PDE8B, in different sexes in vivo by western blot (WB). Meanwhile, C57BL/6J mice were also used to demonstrate the distribution pattern of PDE8 in selected brain regions and localization in neural cells by WB and multiplex immunofluorescence staining. Furthermore, the triple transgenic (3×Tg-AD) mice and wild type (WT) mice of different ages were used to investigate the changes of PDE8 expression in the hippocampus and cerebral cortex during the progression of AD. PDE8 was found to be widely expressed in multiple tissues and organs including heart, kidney, stomach, brain, and liver, spleen, intestines, and uterus, with differences in expression levels between the two subtypes of PDE8A and PDE8B, as well as two sexes. Meanwhile, PDE8 was widely distributed in the brain, especially in areas closely related to cognitive function such as cerebellum, striatum, amygdala, cerebral cortex, and hippocampus, without differences between sexes. Furthermore, PDE8A was found to be expressed in neuronal cells, microglia and astrocytes, while PDE8B is only expressed in neuronal cells and microglia. PDE8A expression in the hippocampus of both female and male 3×Tg-AD mice was gradually increased with ages and PDE8B expression was upregulated only in cerebral cortex of female 3×Tg-AD mice with ages. However, the expression of PDE8A and PDE8B was apparently increased in both cerebral cortex and hippocampus in both female and male 10-month-old 3×Tg-AD mice compared WT mice. These results suggest that PDE8 may be associated with the progression of AD and is a potential target for its prevention and treatment in the future.

Protective effect of PDE4B subtype-specific inhibition in an App knock-in mouse model for Alzheimer's disease

Meta-analysis of genome-wide association study data has implicated PDE4B in the pathogenesis of Alzheimer's disease (AD), the leading cause of senile dementia. PDE4B encodes one of four subtypes of cyclic adenosine monophosphate (cAMP)-specific phosphodiesterase-4 (PDE4A-D). To interrogate the involvement of PDE4B in the manifestation of AD-related phenotypes, the effects of a hypomorphic mutation (Pde4bY358C) that decreases PDE4B's cAMP hydrolytic activity were evaluated in the AppNL-G-F knock-in mouse model of AD using the Barnes maze test of spatial memory, 14C-2-deoxyglucose autoradiography, thioflavin-S staining of β-amyloid (Aβ) plaques, and inflammatory marker assay and transcriptomic analysis (RNA sequencing) of cerebral cortical tissue. At 12 months of age, AppNL-G-F mice exhibited spatial memory and brain metabolism deficits, which were prevented by the hypomorphic PDE4B in AppNL-G-F/Pde4bY358C mice, without a decrease in Aβ plaque burden. RNA sequencing revealed that, among the 531 transcripts differentially expressed in AppNL-G-F versus wild-type mice, only 13 transcripts from four genes - Ide, Btaf1, Padi2, and C1qb - were differentially expressed in AppNL-G-F/Pde4bY358C versus AppNL-G-F mice, identifying their potential involvement in the protective effect of hypomorphic PDE4B. Our data demonstrate that spatial memory and cerebral glucose metabolism deficits exhibited by 12-month-old AppNL-G-F mice are prevented by targeted inhibition of PDE4B. To our knowledge, this is the first demonstration of a protective effect of PDE4B subtype-specific inhibition in a preclinical model of AD. It thus identifies PDE4B as a key regulator of disease manifestation in the AppNL-G-F model and a promising therapeutic target for AD.