NDRG4 Alleviates Myocardial Infarction-Induced Apoptosis through the JAK2/STAT3 Pathway

Shexiang tongxin dropping pill alleviates myocardial injury induced by coronary microembolization by down-regulating APOC1 to inhibit STAT3 signaling pathway

AIM

This study determines to validate the mechanism of Shexiang Tongxin dropping pill (STDP) in attenuating coronary microembolization (CME) induced myocardial injury.

METHODS

CME rat models were established and underwent corresponding treating. Gene chip analysis was performed in rat myocardial tissues for GO and KEGG enrichment analysis. The differentially expressed genes were detected by qRT-PCR. H&E staining and ELISA were used for pathological analysis and detection of troponin (cTnI) and Creatine Kinase Isoenzyme (CK-MB). Lipopolysaccharide (LPS) treated primary cardiomyocytes were used to mimic inflammatory in vitro models. Cell viability and apoptosis of cardiomyocytes were determined by MTT and flow cytometry. The expressions of inflammatory cytokines, apoptotic proteins and proteins related to the STAT3 signal pathway were detected by western blot. APOC1 mRNA expression was detected by qRT-PCR. Immunofluorescence (IF) was used for subcellular localization of p-STAT3 and the binding of APOC1 with STAT3 was verified using Co-IP.

RESULTS

STDP can attenuate myocardial injury in CME rat models, and lead to decreased expression of APOC1 and suppressed STAT3 signal pathway. In vitro models found STDP can suppress the cell viability and cell apoptosis of primary cardiomyocytes, in addition to suppressing the secretions of IL-6, IL-1β and TNF-α, while the protective effect of STDP can be reversed by overexpression of APOC1. Co-IP found that APOC1 can bind STAT3 directly. APOC1 can increase p-STAT3 expression in the nucleus to activate the STAT3 signal pathway.

CONCLUSIONS

STDP can suppress APOC1 and STAT3 signal pathway to inhibit inflammation and cell apoptosis of cardiomyocytes. APOC1 may be one of the key regulatory factors in CME-induced myocardial injury.

Loss of ndrg2 Function Is Involved in Notch Activation in Neuromast Hair Cell Regeneration in Zebrafish

The regeneration of hair cells in zebrafish is a complex process involving the precise regulation of multiple signaling pathways, but this complicated regulatory network is not fully understood. Current research has primarily focused on finding molecules and pathways that can regulate hair cell regeneration and restore hair cell functions. Here, we show the role of N-Myc downstream regulated gene 2 (ndrg2) in zebrafish hair cell regeneration. We first found that ndrg2 was dynamically expressed in neuromasts of the developing zebrafish, and this expression was increased after neomycin-induced hair cell damage. Then, ndrg2 loss-of-function larvae showed reduced numbers of regenerated hair cells but increased numbers of supporting cells after neomycin exposure. By in situ hybridization, we further observed that ndrg2 loss of function resulted in the activation of Notch signaling and downregulation of atoh1a during hair cell regeneration in vivo. Additionally, blocking Notch signaling rescued the number of regenerated hair cells in ndrg2-deficient larvae. Together, this study provides evidence for the role of ndrg2 in regulating hair cell regeneration in zebrafish neuromasts.

Establishment of fingerprint and mechanism of anti-myocardial ischemic effect of Syringa pinnatifolia

OBJECTIVE

To establish the fingerprint of Syringa pinnatifolia Hemsl. (SP), analyze the blood components of SP, and explore the possible mechanism of SP's anti-myocardial ischemia, so as to provide scientific basis for the follow-up development and research of SP and lay a foundation for its clinical application.

METHODS

The fingerprint of SP was established by UPLC-QE-MS and GC-MS. A rat Myocardial infarction (MI) was constructed by ligating the left anterior descending branch (LAD) of the rat coronary artery, and SP alcohol extract was administered to evaluate its anti-myocardial ischemic effect. We analyzed the blood components of SP, screened the active compounds, established a database of SP anti-myocardial ischemic targets, and explored the possible mechanism of SP in treating MI by bioinformatics. The rats were examined by echocardiography, serum biomarkers were determined, and pathological changes were observed by histopathological examination. TUNEL staining was performed to detect the apoptotic level of cells, and western blot and qRT-PCR were performed to detect the expression levels of Bcl-2, Bax and caspase-3 in heart tissues.

RESULTS

In the fingerprint of SP, 24 common peaks were established, and the similarity evaluation results of 10 batches of SP were all > 0.9. UPLC-QE-MS and GC-MS detected a total of 17 active ingredients in the drug-containing serum, including terpenoids, flavonoids, phenols, phenylpropanoids and phenolic acids, the most abundant of which was resveratrol. Enrichment analysis of SP targets against myocardial ischemia revealed that key candidate targets of SP were significantly enriched in multiple pathways associated with apoptosis. Resveratrol was administered to the successfully modeled rats, and the results showed that the resveratrol group significantly reduced LVEDd and LVEDs and significantly increased EF and FS in all groups compared with the model group. Resveratrol significantly reduced the levels of CK-MB and LDH in serum compared to the model group (p < 0.001). Hematoxylin-eosin (HE) staining of rat myocardial tissue showed that all lesions were reduced under microscopic observation in the resveratrol group compared with the model group. RT-PCR and western blot results showed that resveratrol group down-regulated the expression of the pro-apoptotic factor Bax, up-regulated the expression of the anti-apoptotic factor Bcl-2, and decreased the expression of Caspase-3.

CONCLUSION

The established fingerprints are accurate, reliable and reproducible, and can be used as an effective method for the quality control of the herbs. The anti-myocardial ischemia effect of SP may be that resveratrol can improve cardiac function and inhibit cardiomyocyte apoptosis to protect cardiomyocytes. The present study provides ample evidence for the clinical use of SP, suggesting that this drug has great potential in the treatment of ischemic heart disease.