Aerobic exercise inhibits renal EMT by promoting irisin expression in SHR

The role and underlying mechanisms of irisin in exercise-mediated cardiovascular protection

Irisin, a product of the post-translational processing of fibronectin type III domain-containing protein 5 (FNDC5), is a novel myokine which is upregulated during exercise. This hormone not only promotes the transformation of white adipose tissue into a brown-fat-like phenotype but also enhances energy expenditure and mitigates fat accumulation. Its role is crucial in the management of certain metabolic disorders such as diabetes and heart disease. Of note, the type of exercise performed significantly affects blood irisin levels, indicating the critical role of physical activity in regulating this hormone. This article aims to summarize the current scientific understanding of the role of irisin and the mechanisms through which it mediates cardiovascular protection through exercise. Moreover, this article aims to establish irisin as a potential target for preventing and treating cardiovascular diseases.

MICT ameliorates hypertensive nephropathy by inhibiting TLR4/NF-κB pathway and down-regulating NLRC4 inflammasome

BACKGROUND

Hypertensive nephropathy (HN) is one of the main causes of end-stage renal disease (ESRD), leading to serious morbidity and mortality in hypertensive patients. However, existing treatment for hypertensive nephropathy are still very limited. It has been demonstrated that aerobic exercise has beneficial effects on the treatment of hypertension. However, the underlying mechanisms of exercise in HN remain unclear.

METHODS

The spontaneously hypertensive rats (SHR) were trained for 8 weeks on a treadmill with different exercise prescriptions. We detected the effects of moderate intensity continuous training (MICT) and high intensity interval training (HIIT) on inflammatory response, renal function, and renal fibrosis in SHR. We further investigated the relationship between TLR4 and the NLRC4 inflammasome in vitro HN model.

RESULTS

MICT improved renal fibrosis and renal injury, attenuating the inflammatory response by inhibiting TLR4/NF-κB pathway and the activation of NLRC4 inflammasome. However, these changes were not observed in the HIIT group. Additionally, repression of TLR4/NF-κB pathway by TAK-242 inhibited activation of NLRC4 inflammasome and alleviated the fibrosis in Ang II-induced HK-2 cells.

CONCLUSION

MICT ameliorated renal damage, inflammatory response, and renal fibrosis via repressing TLR4/NF-κB pathway and the activation of NLRC4 inflammasome. This study might provide new references for exercise prescriptions of hypertension.

Transcriptome and proteome analyses reveal that upregulation of GSTM2 by allisartan improves cardiac remodeling and dysfunction in hypertensive rats

Long-term hypertension can lead to hypertensive heart disease, which ultimately progresses to heart failure. As an angiotensin receptor blocker antihypertensive drug, allisartan can control blood pressure, and improve cardiac remodeling and cardiac dysfunction caused by hypertension. The aim of the present study was to investigate the protective effects of allisartan on the heart of spontaneously hypertensive rats (SHRs) and the underlying mechanisms. SHRs were used as an animal model of hypertensive heart disease and were treated with allisartan orally at a dose of 25 mg/kg/day. The blood pressure levels of the rats were continuously monitored, their body and heart weights were measured, and their cardiac structure and function were evaluated using echocardiography. Wheat germ agglutinin staining and Masson trichrome staining were employed to assess the morphology of the myocardial tissue. In addition, transcriptome and proteome analyses were performed using the Solexa/Illumina sequencing platform and tandem mass tag technology, respectively. Immunofluorescence co-localization was conducted to analyze Nrf2 nuclear translocation, and TUNEL was performed to detect the levels of cell apoptosis. The protein expression levels of pro-collagen I, collagen III, phosphorylated (p)-AKT, AKT, p-PI3K and PI3K, and the mRNA expression levels of Col1a1 and Col3a1 were determined by western blotting and reverse transcription-quantitative PCR, respectively. Allisartan lowered blood pressure, attenuated cardiac remodeling and improved cardiac function in SHRs. In addition, allisartan alleviated cardiomyocyte hypertrophy and cardiac fibrosis. Allisartan also significantly affected the 'pentose phosphate pathway', 'fatty acid elongation', 'valine, leucine and isoleucine degradation', 'glutathione metabolism', and 'amino sugar and nucleotide sugar metabolism' pathways in the hearts of SHRs, and upregulated the expression levels of GSTM2. Furthermore, allisartan activated the PI3K-AKT-Nrf2 signaling pathway and inhibited cardiomyocyte apoptosis. In conclusion, the present study demonstrated that allisartan can effectively control blood pressure in SHRs, and improves cardiac remodeling and cardiac dysfunction. Allisartan may also upregulate the expression levels of GSTM2 in the hearts of SHRs and significantly affect glutathione metabolism, as determined by transcriptome and proteome analyses. The cardioprotective effect of allisartan may be mediated through activation of the PI3K-AKT-Nrf2 signaling pathway, upregulation of GSTM2 expression and reduction of cardiomyocyte apoptosis in SHRs.

Cardioprotective Effects of Exercise: The Role of Irisin and Exosome

Exercise is an effective measure for preventing and treating cardiovascular diseases, although the exact molecular mechanism remains unknown. Previous studies have shown that both irisin and exosomes can improve the course of cardiovascular disease independently. Therefore, it is speculated that the cardiovascular protective effect of exercise is also related to its ability to regulate the concentrations of irisin and exosomes in the circulatory system. In this review, the potential synergistic interactions between irisin and exosomes are examined, as well as the underlying mechanisms including the AMPK/PI3K/AKT pathway, the TGFβ1/Smad2/3 pathway, the PI3K/AKT/VEGF pathway, and the PTEN/PINK1/Parkin pathway are examined. This paper provides evidence to propose that exercise promotes the release of exosomes enriched with irisin, miR-486-5p and miR-342-5p from skeletal muscles, which results in the activation protective networks in the cardiovascular system. Moreover, the potential synergistic effect in exosomal cargo can provide new ideas for clinical research of exercise mimics.

LncRNA GAS5 downregulates NLRP3 inflammasome activation-mediated pyroptosis in sepsis-induced myocardial injury by targeting SIRT3/AMPKα

An increasing body of studies has demonstrated the significance of long non-coding RNA (lncRNA) growth arrest specific 5 (GAS5) in inflammation and myocardial injury in septic shock. This research aims to determine whether GAS5 contributes to the pathological development of sepsis-induced cardiac damage and NLRP3 inflammasome-mediated myocardial cell pyroptosis. Cecal ligation and puncture (CLP) surgery was used to cause septic shock in C57BL/6 wild-type mice. After CLP, inflammatory, pyroptosis parameters of myocardial tissue, survival rate, and Murine Sepsis Score (MSS) were assessed to evaluate the involvement of GAS5 in the mouse myocardial depression. To investigate GAS5's function in lipopolysaccharide (LPS) induced myocardial cell pyroptosis, gain- and loss-of-function experiments were conducted in vitro on HL-1 cells. Our findings indicated that CLP dramatically reduced survival rates, MSS, SIRT3 and p-AMPK expression, and activated the Nuclear factor-κB (NF-κB) pathway and NLRP3 inflammasome-mediated pyroptosis. The NF-κB and pyroptosis pathways were greatly elevated while SIRT3/p-AMPKα was dramatically decreased as a result of GAS5 being downregulated. Meanwhile, the regulatory effect could be suppressed by SIRT3 and AMPKα activator. Our observations supported the idea that GAS5 has a crucial protective impact against myocardial inflammation and pyroptosis in sepsis.