The interplay between HIF-1α and long noncoding GAS5 regulates the JAK1/STAT3 signalling pathway in hypoxia-induced injury in myocardial cells

Bone marrow mesenchymal stem cells-derived exosomal lncRNA GAS5 mitigates heart failure by inhibiting UL3/Hippo pathway-mediated ferroptosis

BACKGROUND

Exosomes (Exos) are involved in the therapeutic effects of bone marrow mesenchymal stem cells (BMSCs) on heart failure (HF). We investigated the molecular mechanisms underlying the involvement of BMSC-Exos in ferroptosis on HF.

METHODS

A rat model of HF and cellular model of hypoxia were established. BMSC-Exos were injected into model rats or co-cultured with model cells. In model rats, the cardiac function (echocardiography), oxidative stress (commercial kits), pathological damage (HE staining), fibrosis (MASSON staining), iron deposition (Prussian blue staining), and cell apoptosis (TUNEL staining) were examined. Viability (cell counting kit-8; CCK-8), cell cycle (flow cytometry), oxidative stress, and Fe2+ levels were detected in the model cells. GAS5, UL3, YAP, and TAZ expression were detected using qRT-PCR, western blotting, and immunohistochemistry analyses.

RESULTS

BMSC-Exos restored cardiac function and inhibited oxidative stress, apoptosis, pathological damage, fibrosis, and iron deposition in myocardial tissues of HF rats. In hypoxic cells, BMSC-Exos increased cell viability, decreased the number of G1 phase cells, decreased Fe2+ levels, and inhibited oxidative stress. Ferrostatin-1 (a ferroptosis inhibitor) exhibited a synergistic effect with BMSC-Exos. Additionally, GAS5 was upregulated in BMSC-Exos, further upregulating its target UL3 and Hippo pathway effectors (YAP and TAZ). The relieving effects of BMSC-Exos on HF or hypoxia-induced injury were enhanced by GAS5 overexpression, but weakened by UL3 silencing or verteporfin (a YAP inhibitor).

CONCLUSIONS

GAS5-harbouring BMSC-Exos inhibited ferroptosis by regulating the UL3/Hippo pathway, contributing to HF remission in vivo and in vitro.

The Protective Effect of miRNA-146a Liposome Nanoparticles on Vascular Smooth Muscle Cells After Coronary Intervention

The abnormal expression of miRNA-146a is related to the progression of coronary arteries. This study intends to explore the protective effect of miRNA-146a on vascular smooth muscle cells (VSMCs) after coronary intervention and the related mechanism. 10 miniature pigs were randomly assigned into control group, model group, blank group, miRNA-146a group, cilostazol group, and STAT3 signaling agonist group followed by analysis of the morphology and viability of VSMCs, expression of miRNA-146a, STAT3, NF-kB, TNF-a, IL-6, and AT-1R as well as the relationship between miR-146a and STAT3. The BNP (192.39±12.32) pg/ml and cTnI (14.20±2.12) μg/L of model group were significantly higher than those of control group (P < 0.05). miRNA-146a level was highest in miRNA-146a group and cilostazol group, while lower in other two groups with the lowest level in agonist group (P <0.05). The cell viability and AngII level of miRNA-146a group and cilostazol group were lower, and higher in the other two groups with highest level in pathway agonist group (P < 0.05). miRNA-146a group and cilostazol group showed lower expressions of STAT3, NF-kB, TNF-a, IL-6, AT-1R than the other two groups. The pathway agonist group showed significantly higher level than blank group (P <0.05). liposome nanoparticles carrying miRNA-146a inhibited the activity of STAT3 signaling, down-regulated the levels of downstream factors including TNF-a, IL-6, and TNF-a and subsequently decreased AngII and AT-1R levels, therefore playing a protective effect on VSMCs after coronary intervention.