Fibulin7 Mediated Pathological Cardiac Remodeling through EGFR Binding and EGFR-Dependent FAK/AKT Signaling Activation

Examining the potential causal relationships among smoking behaviors, blood DNA methylation profiles, and the development of coronary heart disease and myocardial infarction

BACKGROUND

Smoking has been identified as a standalone risk factor for coronary heart disease (CHD) and myocardial infarction (MI), but the precise underlying mechanisms remain incompletely elucidated.

RESULTS

In this study, we conducted a two-sample Mendelian randomization analysis to examine the impact of smoking behaviors (including smoking initiation, age of smoking initiation, cigarettes per day, and smoking cessation) and smoking-related DNA methylation at CpG sites on CHD and MI based on the UK Biobank dataset. Additionally, we included the FinnGen and Biobank Japan datasets as replications and performed a meta-analysis to combine the results from different data sources. We further validated our results using genetic colocalization analysis. In genomic analysis, we provided compelling evidence on the association between genetically predicted smoking initiation and increased susceptibility to CHD and MI. In epigenetic analysis, we identified 11 smoking-related CpG sites linked to CHD risk and 10 smoking-related CpG sites associated with the risk of MI based on the UK Biobank dataset. Subsequently, some of these CpG sites were further replicated using the FinnGen or BBJ datasets. Ultimately, a meta-analysis was conducted to integrate findings from various data sources (3 for CHD, and 2 for MI), revealing that 7 of 11 CpG sites were linked to CHD risk; whereas, 7 of 10 CpG sites were associated with MI risk. Furthermore, we performed genetic colocalization analysis and found that cg19744173 (FBLN7), cg00395063 (ARHGEF12), and cg16822035 (MCF2L) exhibited robust evidence of colocalization with coronary heart disease; whereas, cg19529732 (DIABLO), cg26405020 (FES), and cg08940075 (CNN3) demonstrated strong colocalization evidence with the risk of myocardial infarction.

CONCLUSIONS

Our research offers a novel insight into the impact of smoking on the susceptibility to CHD and MI through the lens of epigenetic DNA methylation.

FBLN7 mediates vascular smooth muscle cell phenotype switching and vascular remodeling in hypertension

Rationale: Arterial remodeling serves as a pivotal mechanism underlying the development of diseases such as hypertension. Fibulin-7 (FBLN7), an adhesion protein, remains enigmatic regarding its role in these pathological processes. This study aims to explore whether FBLN7 influences vascular remodeling and its underlying mechanisms. Methods: We generated FBLN7 knockout mice and smooth muscle-specific FBLN7 overexpression mice. Vascular remodeling models were established by administering angiotensin II (Ang II) for 28 days. RNA sequencing, western blot, and immunofluorescence assays were employed to investigate the biological function of FBLN7 in vascular smooth muscle cells (VSMCs). The interaction mechanism between FBLN7 and cell membrane receptors was explored through mass spectrometry analysis, co-immunoprecipitation techniques and molecular dynamics simulations. Results: Bioinformatics analysis revealed an upregulation of FBLN7 expression in the vascular remodeling model, with FBLN7 predominantly localized in VSMCs. Subsequent in vivo validation demonstrated that FBLN7 knockout attenuated Ang II-induced vascular remodeling, reducing aortic wall thickness and collagen formation. Conversely, VSMC-specific overexpression of FBLN7 via AAV vectors exacerbating the remodeling phenotype. Functionally speaking, FBLN7 potentiates Ang II-mediated phenotypic transformation. Mechanistically, FBLN7 interacts with the extracellular and transmembrane domains of syndecan-4 (SDC4) via its C-terminal region, affecting SDC4 signaling and dimer formation. This interaction inhibits SDC4-mediated activation of the Rho-associated protein kinase pathway, subsequently reducing nuclear translocation of myocardin-related transcription factor A, leading to decreased transcription of genes associated with the contractile VSMCs phenotype. Conclusions: These findings reveal FBLN7 promotes the transition of VSMCs from a contractile to a synthetic phenotype, thereby aggravating vascular remodeling. This provides further insights into the pathogenesis of vascular remodeling and potential therapeutic strategies.

Intra-articular injection of modified citrus pectin and hyaluronate gel induces synergistic effects in treating osteoarthritis

We previously found that modified citrus pectin (MCP), an inhibitor of pro-inflammatory factor Galectin-3 (Gal-3), has significant anti-inflammatory and chondroprotective effects. In this study, a hyaluronate (HA) gel-based sustained release system of MCP (MCP-HA) was developed as an anti-inflammatory agent for chronic inflammation for osteoarthritis (OA) treatment. The MCP-HA gel was injected into the knee joint cavities of OA rabbit models induced by anterior cruciate ligament transection (ACLT) or modified Hulth method once a week for five weeks. We found that MCP-HA could improve the symptoms and signs of OA, protect articular cartilage from degeneration, suppress synovial inflammation, and therefore alleviate OA progression. Proteomic analysis of the synovial fluid obtained from the knee joints of OA rabbits revealed that MCP-HA synergistically regulated the levels of multiple inflammatory mediators and proteins involved in metabolic pathways. Taken together, our results demonstrate that the MCP-HA shows a synergistic effect of HA and MCP by modulating both inflammation and metabolic processes, thereby alleviating OA progression. The MCP-HA sustained release system has promising potential for long-term use in OA treatment.

Knockdown of SDCBP induces autophagy to promote cardiomyocyte growth and angiogenesis in hypoxia/reoxygenation model

OBJECTIVE

Angina, myocardial infarction, and even mortality can result from myocardial ischemia (MI). Angiogenesis facilitates tissue repair, lessens cell damage, and ensures that ischemic tissues receive blood and oxygen. This study investigated the possible mechanism of syndecan-binding protein (SDCBP) on autophagy and assessed its impact on myocardial ischemia.

METHOD

A cardiac hypoxia-reoxygenation (H/R) cell model was created for this investigation. Flow cytometry, the cell counting kit-8, and Western blotting were used to measure the damage to cardiomyocytes. Western blotting and immunofluorescence were used to quantify autophagy. Furthermore, assays for tube formation, migration, and Western blotting were used to assess angiogenic capacity. Additionally, the EGFR-PI3K-Akt signaling pathway's activation was found using Western blotting.

RESULT

In the H/R-induced cardiomyocyte model, there is a rise in the expression of SDCBP. Treatment with H/R markedly boosted apoptosis and considerably decreased cell survival. H/R induction strongly inhibits autophagy, increases P62 expression, and decreases LC3II/I expression. Moreover, H/R induction dramatically reduced the ability to form tubes, migrate, and express VEGF, all of which prevented cell angiogenesis. Furthermore, EGFR-PI3K-Akt signaling pathway expression is strongly inhibited by H/R induction. considerable reduction of H/R-induced cell damage, considerable inhibition of apoptosis, promotion autophagy and angiogenesis, and activation of the EGFR-PI3K-Akt signaling pathway are all possible with SDCBP knockdown.

CONCLUSION

To summarize, this study demonstrates that via stimulating the EGFR-PI3K-Akt signaling pathway, SDCBP knockdown may mitigate the effects of H/R-induced cardiomyocyte death and encourage autophagy and blood vessel formation. A theoretical foundation for possible myocardial infarction treatment is thus provided.

Pasteurella multocida activates apoptosis via the FAK-AKT-FOXO1 axis to cause pulmonary integrity loss, bacteremia, and eventually a cytokine storm

Pasteurella multocida is an important zoonotic respiratory pathogen capable of infecting a diverse range of hosts, including humans, farm animals, and wild animals. However, the precise mechanisms by which P. multocida compromises the pulmonary integrity of mammals and subsequently induces systemic infection remain largely unexplored. In this study, based on mouse and rabbit models, we found that P. multocida causes not only lung damage but also bacteremia due to the loss of lung integrity. Furthermore, we demonstrated that bacteremia is an important aspect of P. multocida pathogenesis, as evidenced by the observed multiorgan damage and systemic inflammation, and ultimately found that this systemic infection leads to a cytokine storm that can be mitigated by IL-6-neutralizing antibodies. As a result, we divided the pathogenesis of P. multocida into two phases: the pulmonary infection phase and the systemic infection phase. Based on unbiased RNA-seq data, we discovered that P. multocida-induced apoptosis leads to the loss of pulmonary epithelial integrity. These findings have been validated in both TC-1 murine lung epithelial cells and the lungs of model mice. Conversely, the administration of Ac-DEVD-CHO, an apoptosis inhibitor, effectively restored pulmonary epithelial integrity, significantly mitigated lung damage, inhibited bacteremia, attenuated the cytokine storm, and reduced mortality in mouse models. At the molecular level, we demonstrated that the FAK-AKT-FOXO1 axis is involved in P. multocida-induced lung epithelial cell apoptosis in both cells and animals. Thus, our research provides crucial information with regard to the pathogenesis of P. multocida as well as potential treatment options for this and other respiratory bacterial diseases.

Integrated miRNA-mRNA networks underlie attenuation of chronic β-adrenergic stimulation-induced cardiac remodeling by minocycline

Adverse cardiac remodeling contributes to heart failure development and progression, partly due to inappropriate sympathetic nervous system activation. Although β-adrenergic receptor (β-AR) blockade is a common heart failure therapy, not all patients respond, prompting exploration of alternative treatments. Minocycline, an FDA-approved antibiotic, has pleiotropic properties beyond antimicrobial action. Recent evidence suggests it may alter gene expression via changes in miRNA expression. Thus, we hypothesized that minocycline could prevent adverse cardiac remodeling induced by the β-AR agonist isoproterenol, involving miRNA-mRNA transcriptome alterations. Male C57BL/6J mice received isoproterenol (30 mg/kg/day sc) or vehicle via osmotic minipump for 21 days, along with daily minocycline (50 mg/kg ip) or sterile saline. Isoproterenol induced cardiac hypertrophy without altering cardiac function, which minocycline prevented. Total mRNA sequencing revealed isoproterenol altering gene networks associated with inflammation and metabolism, with fibrosis activation predicted by integrated miRNA-mRNA sequencing, involving miR-21, miR-30a, miR-34a, miR-92a, and miR-150, among others. Conversely, the cardiac miRNA-mRNA transcriptome predicted fibrosis inhibition in minocycline-treated mice, involving antifibrotic shifts in Atf3 and Itgb6 gene expression associated with miR-194 upregulation. Picrosirius red staining confirmed isoproterenol-induced cardiac fibrosis, prevented by minocycline. These results demonstrate minocycline's therapeutic potential in attenuating adverse cardiac remodeling through miRNA-mRNA-dependent mechanisms, especially in reducing cardiac fibrosis. NEW & NOTEWORTHY We demonstrate that minocycline treatment prevents cardiac hypertrophy and fibrotic remodeling induced by chronic β-adrenergic stimulation by inducing antifibrotic shifts in the cardiac miRNA-mRNA transcriptome.