The Protective Role of the Long Pentraxin PTX3 in Spontaneously Hypertensive Rats with Heart Failure

Pentraxin 3 promotes the expression of pro-inflammatory cytokines and the migration of macrophages in myocarditis

BACKGROUND

This study aims to investigate the expression of Pentraxin 3 (PTX3) and Nod-like receptor family pyrin domain-containing 3 (NLRP3) in myocarditis and to elucidate their roles and potential interplay in the pathogenesis of myocarditis.

METHODS

Immunofluorescence staining was performed on myocardial autopsy specimens from deceased patients with severe myocarditis or severe trauma. H9C2 cardiomyocytes were divided into five groups: Control, Lipopolysaccharide (LPS), LPS + PTX3 overexpression, LPS + small interfering RNA targeting PTX3 (si-PTX3), and LPS + PTX3 overexpression + si-NLRP3. The expression levels of PTX3 and NLRP3 at the RNA level were quantified using quantitative real-time polymerase chain reaction (qPCR), while protein expression was assessed via western blot. The concentrations of interleukin-1β (IL-1β) and IL-18 were determined by enzyme-linked immunosorbent assay (ELISA). Macrophages migration was evaluated using Transwell assays.

RESULTS

Immunofluorescence staining revealed co-localization and increased expression of PTX3 and NLRP3 in the myocardium of patients with severe myocarditis. In vitro experiments demonstrated that PTX3 enhanced the expression of NLRP3, IL-1β, and IL-18 in LPS-stimulated cardiomyocytes. Furthermore, PTX3 was shown to promote macrophage migration by regulating NLRP3 expression, as assessed by Transwell assays.

CONCLUSION

Our findings suggest that PTX3-mediated NLRP3 activation contributes to inflammatory responses and promotes macrophage migration in myocarditis. This study provides a foundation for future investigations into PTX3-targeted therapies for myocarditis.

Renal denervation improves mitochondrial oxidative stress and cardiac hypertrophy through inactivating SP1/BACH1-PACS2 signaling

BACKGROUND

Renal denervation (RDN) has been proved to relieve cardiac hypertrophy; however, its detailed mechanisms remain obscure. This study investigated the detailed protective mechanisms of RDN against cardiac hypertrophy during hypertensive heart failure (HF).

METHODS

Male 5-month-old spontaneously hypertension (SHR) rats were used in a HF rat model, and male Wistar-Kyoto (WKY) rats of the same age were used as the baseline control. Myocardial hypertrophy and fibrosis were evaluated by hematoxylin-eosin (HE) staining and Masson staining. The expression of target molecule was analyzed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blot, immunohistochemical and immunofluorescence, respectively. Cardiomyocyte hypertrophy was induced by norepinephrine (NE) in H9c2 cells in vitro and evaluated by brain natriuretic peptide (BNP), atrial natriuretic peptide (ANP), β-myosin heavy chain (β-MHC), and α-myosin heavy chain (α-MHC) levels. Oxidative stress was determined by malondialdehyde (MDA) level, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) enzyme activities. Mitochondrial function was measured by mitochondrial membrane potential, adenosine triphosphate (ATP) production, mitochondrial DNA (mtDNA) number, and mitochondrial complex I-IV activities. Molecular mechanism was assessed by dual luciferase reporter and chromatin immunoprecipitation (ChIP) assays.

RESULTS

RDN decreased sympathetic nerve activity, attenuated myocardial hypertrophy and fibrosis, and improved cardiac function in the rat model of HF. In addition, RDN ameliorated mitochondrial oxidative stress in myocardial tissues as evidenced by reducing MDA and mitochondrial reactive oxygen species (ROS) levels, and enhancing SOD and GSH-Px activities. Moreover, phosphofurin acid cluster sorting protein 2 (PACS-2) and broad-complex, tramtrak and bric à brac (BTB) domain and cap'n'collar (CNC) homolog 1 (BACH1) were down-regulated by RDN. In NE-stimulated H9c2 cells, PACS-2 and BACH1 levels were markedly elevated, and knockdown of them could suppress NE-induced oxidative stress, cardiomyocyte hypertrophy, fibrosis, as well as mitochondrial dysfunction. Transforming growth factor beta1(TGFβ1)/SMADs signaling pathway was inactivated by RDN in the HF rats, which sequentially inhibited specificity protein 1 (SP1)-mediated transcription of PACS2 and BACH1.

CONCLUSION

Collectively, these data demonstrated that RDN improved cardiac hypertrophy and sympathetic nerve activity of HF rats via repressing BACH1 and PACS-2-mediated mitochondrial oxidative stress by inactivating TGF-β1/SMADs/SP1 pathway, which shed lights on the cardioprotective mechanism of RDN in HF.

Pentraxin 3: A promising therapeutic target for cardiovascular diseases

Cardiovascular disease (CVD) is the primary global cause of death, and inflammation is a crucial factor in the development of CVDs. The acute phase inflammatory protein pentraxin 3 (PTX3) is a biomarker reflecting the immune response. Recent research indicates that PTX3 plays a vital role in CVDs and has been investigated as a possible biomarker for CVD in clinical trials. PTX3 is implicated in the progression of CVDs through mechanisms such as exacerbating vascular endothelial dysfunction, affecting angiogenesis, and regulating inflammation and oxidative stress. This review summarized the structure and function of PTX3, focusing on its multifaceted effects on CVDs, such as atherosclerosis, myocardial infarction, and hypertension. This may help in explaining the varying PTX3 functions and usage, as well as in utilizing target organs to manage diseases. Moreover, elucidating the opposite role of PTX3 in the cardiovascular system will demonstrate the therapeutic and predictive potential in human diseases.

Serum exosomes derived from spontaneously hypertensive rats induce cardiac hypertrophy in vitro and in vivo by increasing autocrine release of angiotensin II in cardiomyocytes

Identifying the key factors mediating the progression from hypertension to cardiac hypertrophy is critically important for developing a strategy to protect against heart failure. Serum exosomes have been revealed to be involved in the development of cardiovascular disease. In the current study, we found that either serum or serum exosomes derived from SHR induced hypertrophy in H9c2 cardiomyocytes. SHR Exo injection through the tail vein for 8 weeks induced left ventricular wall thickening and decreased cardiac function in C57BL/6 mice. SHR Exo carried the renin-angiotensin system (RAS) proteins AGT, renin, and ACE into cardiomyocytes, which increased the autocrine secretion of Ang II. Moreover, the AT1-type receptor antagonist telmisartan prevented hypertrophy of H9c2 cells induced by SHR Exo.These results identified a novel role of exosomes derived from SHR serum in cardiac hypertrophy and revealed that SHR Exo induced cardiac hypertrophy by carrying AGT, renin, and ACE proteins into cardiomyocytes to increase their autocrine secretion of Ang II. The emergence of this new mechanism will help us better understand how hypertension progresses to cardiac hypertrophy.

Pentraxin-3 – a promising biological marker in heart failure: literature review

According to many studies, inflammation plays a very significant role in the pathogenesis of heart failure. Many studies have demonstrated an increase in circulating levels of inflammatory markers and cytokines such as C-reactive protein, tumor necrosis factor-a (TNF-a), and interleukins. C-reactive protein is produced in the liver in response to stimulation by various cytokines, mainly interleukin-6, and is a member of the pentraxin superfamily. Pentraxin-3, which is a long pentraxin, has a C-terminal domain of pentraxin similar to the classic short pentraxins, but differs from them in the presence of an unrelated long N-terminal domain. Various cell types can produce pentraxin-3 when exposed to primary inflammatory signals such as interleukin-1, tumor necrosis (TNF-a), oxidized low density lipoprotein, and microbial fragments (eg, lipopolysaccharide, lipoarabinomannans). Data in experimental animal models have demonstrated that pentraxin-3 can play cardioprotective and atheroprotective roles through its influence on the inflammatory process. Pentraxin-3 has been studied in several clinical protocols as a potential biomarker for cardiovascular disease.