Qingxin Kaiqiao Fang Inhibits Aβ_25-35‐Induced Apoptosis in Primary Cultured Rat Hippocampal Neuronal Cells via the p38 MAPK Pathway: An Experimental Validation and Network Pharmacology Study

Abstract

Qingxin kaiqiao fang (QKF), a traditional Chinese medicine compound, has been applied to treat Alzheimer’s disease (AD) for many years and has exhibited remarkable effects. However, the underlying mechanism is still not explicit. The current study aims to investigate whether QKF exerts an antiapoptotic role through the p38 MAPK pathway in the course of AD. Network pharmacology analysis was applied to study the effective components, possible therapeutic targets, and AD-related pathway of QKF. Further, the AD cell model was established using amyloid-beta (Aβ)25-35 peptide and primary hippocampal neuronal cells extracted from newborn Sprague-Dawley rats. Microtubule-associated protein-2 (MAP-2) imaging was used to detect the morphology of hippocampal neurons. Western blot (WB) analysis was applied to detect the protein expression levels of p38 MAPK, p-p38 MAPK, Bcl-2, Bax, caspase-3, and cleaved caspase-3. Cell viability and apoptosis were determined using cell counting kit-8 (CCK-8) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assays, respectively. SB203580 and U46619 were used to detect changes in cell morphology, cell viability, and apoptosis upon inhibiting or activating p38 MAPK. Our present work showed that QKF protects hippocampal neuronal morphology, enhances cell viability, and reduces the number of TUNEL-positive cells. In addition, our results showed that QKF increased the expression levels of antiapoptotic proteins and decreased the expression of proapoptotic proteins. QKF at 25 mg·mL−1 best inhibited neuronal apoptosis among the three doses of QKF by suppressing p38 MAPK activity. Collectively, QKF plays an antiapoptotic role via the p38 MAPK pathway.

Medicinal Herbs and Their Derived Ingredients Protect against Cognitive Decline in In Vivo Models of Alzheimer’s Disease

“…Moreover, MAPKs are key modulators of cell growth, differentiation, development, cell survival, and apoptosis [ 119 , 120 ]. In general, ERK1/2-mediated signaling is involved in cell survival, proliferation, and development, whereas p38 MAPK- and JNK-mediated signaling triggers mitochondria-related neuronal apoptosis in response to various types of stress stimuli [ 21 , 25 , 121 ]. However, ERK1/2-mediated signaling also triggers Aβ-induced apoptosis in a rat model of ibotenic acid (IBO)-induced AD [ 122 ].…”

“…However, ERK1/2-mediated signaling also triggers Aβ-induced apoptosis in a rat model of ibotenic acid (IBO)-induced AD [ 122 ]. Aβ accumulation leads to the phosphorylation of p38 MAPK, which subsequently triggers tau hyperphosphorylation, disrupts synaptic plasticity, and eventually, elicits hippocampal neuronal apoptosis [ 25 ]. JNK is activated by the upstream factors including apoptosis signal-regulating kinase 1 (ASK1), MAPK kinase (MKK) 4 and MKK7.…”

“…In addition, Aβ 25–35 can be generated through the enzymatic cleavage of Aβ 1–40 [ 24 ]. Among the Aβ fragments, Aβ 25–35 is the shortest, but has the neurotoxic properties of a full-length Aβ peptide and presents a high level of aggregation during AD pathogenesis [ 25 ]. In general, Aβ oligomer deposition, an early event in AD pathogenesis, elicits neurotoxicity, oxidative stress, synaptic dysfunction, calcium overload, inflammatory cascades, and aberrant tau hyperphosphorylation in lesions [ 6 , 26 , 27 ].…”