DEL-1 deficiency aggravates pressure overload-induced heart failure by promoting neutrophil infiltration and neutrophil extracellular traps formation

Cardiomyocyte LGR6 alleviates ferroptosis in diabetic cardiomyopathy via regulating mitochondrial biogenesis

AIMS

The majority of people with diabetes are susceptible to cardiac dysfunction and heart failure, and conventional drug therapy cannot correct the progression of diabetic cardiomyopathy. We assessed the potential role and therapeutic value of LGR6 (G protein-coupled receptor containing leucine-rich repeats 6) in diabetic cardiomyopathy.

METHODS AND RESULTS

Type 2 diabetes models were established using high-fat diet/streptozotocin-induced diabetes in mice. LGR6 knockout mice were generated. Recombinant adeno-associated virus serotype 9 carrying LGR6 under the cardiac troponin T promoter was injected into diabetic mice. Cardiomyocytes incubated with high glucose (HG) were used to imitate diabetic cardiomyopathy in vitro. The molecular mechanism was explored through RNA sequencing and a chromatin immunoprecipitation assay. We found that LGR6 expression was upregulated in diabetic hearts and HL1 cardiomyocytes treated with HG. The LGR6 knockout aggravated, but cardiomyocyte-specific LGR6 overexpression ameliorated, cardiac dysfunction and remodeling in diabetic mice. Mechanistically, in vivo and in vitro experiments revealed that LGR6 deletion aggravated, whereas LGR6 overexpression alleviated, ferroptosis and disrupted mitochondrial biogenesis by regulating STAT3/Pgc1a signaling. STAT3 inhibition and Pgc1a activation abrogated LGR6 knockout-induced mitochondrial dysfunction and ferroptosis in diabetic mice. In addition, LGR6 activation by recombinant RSPO3 treatment ameliorated cardiac dysfunction, ferroptosis and mitochondrial dysfunction in diabetic mice.

CONCLUSIONS

We identified a previously undescribed signaling pathway of the LGR6-STAT3-Pgc1a axis that plays a critical role in ferroptosis and mitochondrial disorders during diabetic cardiomyopathy and provides an option for treatment of diabetic hearts.

Developmental endothelial locus 1: the present and future of an endogenous factor in vessels

Developmental Endothelial Locus-1 (DEL-1), also known as EGF-like repeat and discoidin I-like domain-3 (EDIL3), is increasingly recognized for its multifaceted roles in immunoregulation and vascular biology. DEL-1 is a protein that is mainly produced by endothelial cells. It interacts with various integrins to regulate the behavior of immune cells, such as preventing unnecessary recruitment and inflammation. DEL-1 also helps in resolving inflammation by promoting efferocytosis, which is the process of clearing apoptotic cells. Its potential as a therapeutic target in immune-mediated blood disorders, cardiovascular diseases, and cancer metastasis has been spotlighted due to its wide-ranging implications in vascular integrity and pathology. However, there are still unanswered questions about DEL-1's precise functions and mechanisms. This review provides a comprehensive examination of DEL-1's activity across different vascular contexts and explores its potential clinical applications. It underscores the need for further research to resolve existing controversies and establish the therapeutic viability of DEL-1 modulation.

Immuno-inflammatory pathogenesis in ischemic heart disease: perception and knowledge for neutrophil recruitment

Ischemic heart disease (IHD) can trigger responses from the innate immune system, provoke aseptic inflammatory processes, and result in the recruitment and accumulation of neutrophils. Excessive recruitment of neutrophils is a potential driver of persistent cardiac inflammation. Once recruited, neutrophils are capable of secreting a plethora of inflammatory and chemotactic agents that intensify the inflammatory cascade. Additionally, neutrophils may obstruct microvasculature within the inflamed region, further augmenting myocardial injury in the context of IHD. Immune-related molecules mediate the recruitment process of neutrophils, such as immune receptors and ligands, immune active molecules, and immunocytes. Non-immune-related molecular pathways represented by pro-resolving lipid mediators are also involved in the regulation of NR. Finally, we discuss novel regulating strategies, including targeted intervention, agents, and phytochemical strategies. This review describes in as much detail as possible the upstream molecular mechanism and external intervention strategies for regulating NR, which represents a promising therapeutic avenue for IHD.

Right Lower Pulmonary Vein Thrombi and Right Upper Pulmonary Vein Thrombi Connected on the Anterior Wall of the Left Atrium

The interaction between the right upper pulmonary vein (RUPV) and the right lower pulmonary vein (RLPV) is poorly understood. In this paper, using transesophageal echocardiography (TEE) and 80-slice multidetector computed tomography (80-MDCT), we report that the RUPV thrombi and the RLPV thrombi invade the left atrium (LA) and reach the anterior wall of the LA. To our knowledge, this is the first study to directly show the connection between the RUPV thrombi and the RLPV thrombi on the anterior wall of the LA using TEE and 80-MDCT.

Epidermal Growth Factor-Like Repeats and Discoidin I-Like Domains 3 Deficiency Attenuates Dilated Cardiomyopathy by Inhibiting Ubiquitin Specific Peptidase 10 Dependent Smad4 Deubiquitination

BACKGROUND

Dilated cardiomyopathy (DCM) is the leading cause of heart failure with a poor prognosis. Recent studies suggest that endothelial to mesenchymal transition (EndMT) may be involved in the pathogenesis and cardiac remodeling during DCM development. EDIL3 (epidermal growth factor-like repeats and discoidin I-like domains 3) is an extracellular matrix glycoprotein that has been reported to promote EndMT in various diseases. However, the roles of EDIL3 in DCM still remain unclear.

METHODS AND RESULTS

A mouse model of DCM and human umbilical vein endothelial cells were used to explore the roles and mechanisms of EDIL3 in DCM. The results indicated that EndMT and EDIL3 were activated in DCM mice. EDIL3 deficiency attenuated cardiac dysfunction and remodeling in DCM mice. EDIL3 knockdown alleviated EndMT by inhibiting USP10 (ubiquitin specific peptidase 10) dependent Smad4 deubiquitination in vivo and in vitro. Recombinant human EDIL3 promoted EndMT via reinforcing deubiquitination of Smad4 in human umbilical vein endothelial cells treated with IL-1β (interleukin 1β) and TGF-β (transforming growth factor beta). Inhibiting USP10 abolished EndMT exacerbated by EDIL3. In addition, recombinant EDIL3 also aggravates doxorubicin-induced EndMT by promoting Smad4 deubiquitination in HUVECs.

CONCLUSIONS

Taken together, these results indicate that EDIL3 deficiency attenuated EndMT by inhibiting USP10 dependent Smad4 deubiquitination in DCM mice.

Left Atrial Diverticula Supplied by the Anomalistic Branch of the Right Coronary Artery

We have reported several cases of pulmonary vein thrombosis in elderly individuals with or without chest pain; pulmonary vein thrombosis is common in aged individuals and should be evaluated further. However, the properties and roles of pulmonary vein thrombi (PVTs) have not been determined. During infection, neutrophil extracellular traps (NETs) are produced to kill pathogens, and arterial thrombi (ATs) are produced in pulmonary veins to prevent pathogens from spreading to all organs. We reported that fine PVTs became larger PVTs and extended to the LA wall. PVTs can cause acute myocardial infarction (AMI) and ischemic stroke (IS) by releasing larger particles; therefore, the characteristics of PVTs need to be determined to prevent the occurrence of AMI and IS. PVTs can cause several diseases by releasing smaller particles, such as NETs, for which cumulative effects should be determined. PVTs and their effects on human health need to be studied to avoid missing the chances of treating patients with these diseases moderately. We reported that PVTs often extend to the left atrium (LA) and attach to the LA wall; however, the effects of attachment remain unclear. According to cardiac computed tomography (CT), left atrial diverticula (LADs) reportedly occur in 10%-50% of patients; however, the details of the LAD are unknown. Therefore, we examined the relationships among PVTs, LA thrombi, and LADs using cardiac CT and transesophageal echocardiography (TEE). The patient was a 65-year-old male with hypertension and severe palpitations. He had no history of AMI or IS. TEE revealed that the LA thrombi were attached to the anterior wall of the right lower pulmonary vein and that they were attached to the anterior wall of the LA. TEE revealed an LAD near the attachment area. Cardiac CT revealed an LAD without thrombi near the attachment area. Sagittal images from a cardiac CT scan revealed that a part of the attachment region in the LA was a dark line, where no blood flow was observed in the LA, and that there seemed to be the LAD on top of the dark line. The anomalistic branch of the right coronary artery (#1) connected around the top of the LAD.

Left Atrial Diverticula Present in the Right Lower Pulmonary Vein Thrombus Attachment Area

Left atrial diverticula (LADs) are thought to be associated with atrial fibrillation and an ischemic brain state. However, the mechanisms of LAD formation are unknown. Pulmonary vein thrombi (PVTs) can cause acute myocardial infarction (AMI) and ischemic stroke by releasing rather large particles. Additionally, PVTs can release much smaller particles, including neutrophil extracellular traps (NETs) and/or other components of NETs, such as DNA and histones. To treat these diseases, it may be crucial to know the specific traits of PVTs. However, these issues are not direct effects of PVTs on the left atrium (LA). It is unclear whether PVTs affect the LA directly. We checked the direct effects of PVTs on the LA using cardiac computed tomography (CT) and transesophageal echocardiography (TEE). The patient was a 73-year-old female with hypertension. TEE revealed extended LA thrombi from the right lower pulmonary vein, which were attached to the anterosuperior wall of the LA. Cardiac CT revealed the attaching area as a defect of enhancement and dimly revealed LAD with full thrombi on the attaching area. It was difficult to recognize the LAD at first; however, after one month of standard-dose heparin-warfarin treatment, the LAD was clearly detected using cardiac CT. LA thrombi could not be detected using cardiac CT.