HSF1 Relieves Amyloid-β-Induced Cardiomyocytes Apoptosis

Guanxinning tablets improve myocardial hypertrophy by inhibiting the activation of MEK-ERK1/2 signaling pathway

Myocardial hypertrophy may lead to heart failure and sudden death. As traditional Chinese medicine, Guanxinning tablets (GXN) have significant pharmacological effects in the prevention and treatment of cardiovascular diseases. However, the anti-cardiac hypertrophy efficacy of GXN and its mechanism of action are still unclear. Therefore, we established a heart failure rat model and isolated primary cardiomyocytes of neonatal rat to observe the protective effect of GXN on heart failure rat model and the intervention effect on myocardial cell hypertrophy, and to explore the possible mechanism of GXN preventing and treating myocardial hypertrophy. The results of in vivo experiments showed that GXN could significantly reduce the degree of cardiac hypertrophy, reduce the size of cardiomyocytes, inhibit the degree of myocardial remodeling and fibrosis, and improve cardiac function in rats with early heart failure. The results of in vitro experiments showed that GXN was safe for primary cardiomyocytes and could improve cardiomyocyte hypertrophy and reduce the apoptosis of cardiomyocytes in pathological state, which may be related to the inhibition of the over-activation of MEK-ERK1/2 signaling pathway. In conclusion, GXN may inhibit cardiac hypertrophy and improve early heart failure by inhibiting the over-activation of MEK-ERK1/2 signaling pathway.

Mitochondrial aldehyde dehydrogenase (ALDH2) rescues cardiac contractile dysfunction in an APP/PS1 murine model of Alzheimer's disease via inhibition of ACSL4-dependent ferroptosis

Alzheimer's disease (AD) is associated with high incidence of cardiovascular events but the mechanism remains elusive. Our previous study reveals a tight correlation between cardiac dysfunction and low mitochondrial aldehyde dehydrogenase (ALDH2) activity in elderly AD patients. In the present study we investigated the effect of ALDH2 overexpression on cardiac function in APP/PS1 mouse model of AD. Global ALDH2 transgenic mice were crossed with APP/PS1 mutant mice to generate the ALDH2-APP/PS1 mutant mice. Cognitive function, cardiac contractile, and morphological properties were assessed. We showed that APP/PS1 mice displayed significant cognitive deficit in Morris water maze test, myocardial ultrastructural, geometric (cardiac atrophy, interstitial fibrosis) and functional (reduced fractional shortening and cardiomyocyte contraction) anomalies along with oxidative stress, apoptosis, and inflammation in myocardium. ALDH2 transgene significantly attenuated or mitigated these anomalies. We also noted the markedly elevated levels of lipid peroxidation, the essential lipid peroxidation enzyme acyl-CoA synthetase long-chain family member 4 (ACSL4), the transcriptional regulator for ACLS4 special protein 1 (SP1) and ferroptosis, evidenced by elevated NCOA4, decreased GPx4, and SLC7A11 in myocardium of APP/PS1 mutant mice; these effects were nullified by ALDH2 transgene. In cardiomyocytes isolated from WT mice and in H9C2 myoblasts in vitro, application of Aβ (20 μM) decreased cell survival, compromised cardiomyocyte contractile function, and induced lipid peroxidation; ALDH2 transgene or activator Alda-1 rescued Aβ-induced deteriorating effects. ALDH2-induced protection against Aβ-induced lipid peroxidation was mimicked by the SP1 inhibitor tolfenamic acid (TA) or the ACSL4 inhibitor triacsin C (TC), and mitigated by the lipid peroxidation inducer 5-hydroxyeicosatetraenoic acid (5-HETE) or the ferroptosis inducer erastin. These results demonstrate an essential role for ALDH2 in AD-induced cardiac anomalies through regulation of lipid peroxidation and ferroptosis.

Senkyunolide I attenuates oxygen-glucose deprivation/reoxygenation-induced inflammation in microglial cells

Over-activated microglia during stroke has been documented to aggravate brain damage. Our previous studies showed that senkyunolide I (SEI) exerted anti-inflammatory effects against endotoxin insult in vitro and ameliorative effects on cerebral ischemia/reperfusion (I/R) injury in vivo. Using oxygen-glucose deprivation/reoxygenation (OGD/R) to mimic stroke, we here investigated the anti-inflammatory effect of SEI on microglial cells and explored the underlying mechanisms. OGD for 3h followed by reoxygenation for 12h significantly enhanced the release of pro-inflammatory cytokines and expressions of inflammation-related enzymes in BV-2 cells, which was inhibited by pretreatment with SEI. To elucidate the mechanisms, we studied its effect on upstream signaling pathways. It was found that SEI suppressed the activation of NF-κB pathway induced by OGD/R and the MAPK pathway was shown not to be involved. Furthermore, SEI significantly down-regulated TLR4/MyD88 pathway with specifically improving inducible Hsp70 level through increasing HSF-1/DNA binding activity, and these regulations responsive to SEI were attenuated by transfecting Hsp70 siRNA and HSF-1 decoy ODNs. Additionally, SEI exerted similar influence on Hsp70/TLR4/NF-κB pathway in rat primary microglial cells. The results suggested that SEI had a potent effect against stroke-induced neuroinflammation through suppressing the TLR4/NF-κB pathway by up-regulating Hsp70 dependent on HSF-1.