Is KCNH1 mutation related to coronary artery ectasia

Could Aneurysm and Atherosclerosis-Associated MicroRNAs (miR 24-1-5p, miR 34a-5p, miR 126-5p, miR 143-5p, miR 145-5p) Also Be Associated with Coronary Artery Ectasia?

Background: Coronary artery ectasia (CAE), known for localized or diffuse excessive dilatation of the coronary artery, has an unknown etiology, but it has been reported that the underlying cause may be atherosclerosis and genetic changes that may affect the arterial lumen. MicroRNAs have been shown to have an effect in aneurysm diseases and are known to contribute to vascular development and atherosclerosis. The purpose of this study was to investigate whether they are also associated with CAE. Methods: This cross-sectional study consisted of 25 patients with CAE and 25 subjects with normal coronary arteries. Blood was collected and miRNA expression was detected using the Rotor-GeneQ real-time polymerase chain reaction cycler (Qiagen) to investigate expression levels of miR-24-1-5p, miR-34a-5p, miR-126-5p, miR-143-5p, and miR-145-5p. Results: Demographic variables of CAE (mean age 59.5 ± 1.7; 12 women) and controls (mean age 57.2 ± 2.1; 16 women) were similar. miR-126-5p (p = 0.014) and miR-145-5p (p = 0.003) levels were found to be <2-fold upregulated in CAE compared to controls; miR-143-5p also showed upregulation, but it was not significant (p = 0.078). Conversely, miR-24-1-5p (p = 0.032) levels were downregulated in CAE compared to controls. miR-34a-5p was also downregulated, but this was not considered significant (p = 0.185). Conclusions: According to our study findings, miR-126-5p, miR-145-5p, and miR-24-1-5p may be associated with CAE. These microRNAs could be of diagnostic and therapeutic significance for further studies of CAE involving abnormal angiogenesis and vascular disorders and potentially serve as useful biomarkers.

Next-generation sequencing of prolidase gene identifies novel and common variants associated with low prolidase in coronary artery ectasia

BACKGROUND

Decreased collagen biosynthesis and increased collagenolysis can cause ectasia progression in the arterial walls. Prolidase is a key enzyme in collagen synthesis; a decrease in prolidase activity or level may decrease collagen biosynthesis, which may contribute to ectasia formation. Considering that, the variations in PEPD gene encoding prolidase enzyme were evaluated by analyzing next-generation sequencing (NGS) for the first time together with known risk factors in coronary artery ectasia (CAE) patients.

METHODS

Molecular analysis of the PEPD gene was performed on genomic DNA by NGS in 76 CAE patients and 76 controls. The serum levels of prolidase were measured by the sandwich-ELISA technique.

RESULTS

Serum prolidase levels were significantly lower in CAE group compared to control group, and it was significantly lower in males than females in both groups (p < 0.001). On the other hand, elevated prolidase levels were observed in CAE patients in the presence of diabetes (p < 0.001), hypertension (p < 0.05) and hyperlipidemia (p < 0.05). Logistic regression analysis demonstrated that the low prolidase level (p < 0.001), hypertension (p < 0.02) and hyperlipidemia (p < 0.012) were significantly associated with increased CAE risk. We identified four missense mutations in the PEPD gene, namely G296S, T266A, P365L and S134C (novel) that could be associated with CAE. The pathogenicity of these mutations was predicted to be "damaging" for G296S, S134C and P365L, but "benign" for T266A. We also identified a novel 5'UTR variation (Chr19:34012748 G>A) in one patient who had a low prolidase level. In addition, rs17570 and rs1061338 common variations of the PEPD gene were associated with low prolidase levels in CAE patients, while rs17569 variation was associated with high prolidase levels in both CAE and controls (p < 0.05).

CONCLUSIONS

Our findings indicate that the low serum prolidase levels observed in CAE patients is significantly associated with PEPD gene variations. It was concluded that low serum prolidase level and associated PEPD mutations may be potential biomarkers for the diagnosis of CAE.

Insights into lipid metabolism and immune-inflammatory responses in the pathogenesis of coronary artery ectasia

Coronary artery ectasia (CAE) is a rare finding that is associated with poor clinical outcomes (Kawsara et al. 2018), and disorders in lipid metabolism have been reported in CAE. Lipids constitute one of the three metabolite types that regulate bodily functions and are also powerful signaling molecules (Han 2016; Zhu et al. 2021) that affect immunoregulation and inflammatory responses via a series of transcription factors and signaling pathways (Barrera et al. 2013). Although abnormal lipid metabolism and immunoinflammatory responses have been reported in CAE, their roles in the pathogenic mechanisms underlying CAE are currently unclear.

Intracellular hemin is a potent inhibitor of the voltage-gated potassium channel Kv10.1

Heme, an iron-protoporphyrin IX complex, is a cofactor bound to various hemoproteins and supports a broad range of functions, such as electron transfer, oxygen transport, signal transduction, and drug metabolism. In recent years, there has been a growing recognition of heme as a non-genomic modulator of ion channel functions. Here, we show that intracellular free heme and hemin modulate human ether à go-go (hEAG1, Kv10.1) voltage-gated potassium channels. Application of hemin to the intracellular side potently inhibits Kv10.1 channels with an IC₅₀ of about 4 nM under ambient and 63 nM under reducing conditions in a weakly voltage-dependent manner, favoring inhibition at resting potential. Functional studies on channel mutants and biochemical analysis of synthetic and recombinant channel fragments identified a heme-binding motif CxHx₈H in the C-linker region of the Kv10.1 C terminus, with cysteine 541 and histidines 543 and 552 being important for hemin binding. Binding of hemin to the C linker may induce a conformational constraint that interferes with channel gating. Our results demonstrate that heme and hemin are endogenous modulators of Kv10.1 channels and could be exploited to modulate Kv10.1-mediated cellular functions.

Identification of candidate biomarkers and pathways associated with type 1 diabetes mellitus using bioinformatics analysis

Type 1 diabetes mellitus (T1DM) is a metabolic disorder for which the underlying molecular mechanisms remain largely unclear. This investigation aimed to elucidate essential candidate genes and pathways in T1DM by integrated bioinformatics analysis. In this study, differentially expressed genes (DEGs) were analyzed using DESeq2 of R package from GSE162689 of the Gene Expression Omnibus (GEO). Gene ontology (GO) enrichment analysis, REACTOME pathway enrichment analysis, and construction and analysis of protein–protein interaction (PPI) network, modules, miRNA-hub gene regulatory network and TF-hub gene regulatory network, and validation of hub genes were performed. A total of 952 DEGs (477 up regulated and 475 down regulated genes) were identified in T1DM. GO and REACTOME enrichment result results showed that DEGs mainly enriched in multicellular organism development, detection of stimulus, diseases of signal transduction by growth factor receptors and second messengers, and olfactory signaling pathway. The top hub genes such as MYC, EGFR, LNX1, YBX1, HSP90AA1, ESR1, FN1, TK1, ANLN and SMAD9 were screened out as the critical genes among the DEGs from the PPI network, modules, miRNA-hub gene regulatory network and TF-hub gene regulatory network. Receiver operating characteristic curve (ROC) analysis confirmed that these genes were significantly associated with T1DM. In conclusion, the identified DEGs, particularly the hub genes, strengthen the understanding of the advancement and progression of T1DM, and certain genes might be used as candidate target molecules to diagnose, monitor and treat T1DM.

Pharmacologic Management of Coronary Artery Ectasia

Coronary artery ectasia (CAE) is a rare form of aneurysmal coronary heart disease. It is defined as a dilatation of the coronary artery by more than one-third of its length and with a diameter 1.5 times of a normal coronary artery adjacent to it. This condition increases the risk of angina pectoris and acute coronary syndrome. Hence, we discuss the pharmacologic options for primary and secondary prevention of CAE complications. Antiplatelets such as aspirin are considered the mainstay of treatment in patients with CAE. Anticoagulants such as warfarin are warranted on a case-by-case basis to prevent thrombus formation depending on the presence of concomitant obstructive coronary artery disease and the patient’s risk of bleeding. Since atherosclerosis is the most common cause of CAE, statins are indicated in all patients for primary prevention. Angiotensin-converting enzyme (ACE) inhibitors may be indicated, especially in hypertensive patients, due to their anti-inflammatory properties. Beta-blockers may be indicated due to their antihypertensive and anti-ischemic effects. Calcium (Ca) channel blockers may be needed to prevent coronary vasospasm. Nitrates are generally contraindicated as they may lead to worsening of symptoms. Other antianginal medications such as trimetazidine can improve exercise tolerance with no reported adverse events in these patients.