Genetic Regulatory Networks of Apolipoproteins and Associated Medical Risks

Genetic Markers of Cardiovascular Disease

Cardiovascular Disorders (CVDs) are the leading cause mortality in developed as well as developing nations, and has now emerged as one of the leading causes of disability and mortality around the globe. According to the World Health Organization, four out of every five patients with cardiovascular disease die from a myocardial infarction each year. Numerous genes have been linked to coronary artery disease, influencing mechanisms such as blood pressure regulation, lipid metabolism, inflammation, and cardiac activity. Genetic variations or mutations in these genes can affect lipid metabolism, blood pressure management, and heart function, increasing the risk of obesity, metabolic disorders, and resulting in the development of cardiovascular disease. Understanding the role of genes and related complications are essential for the identification, management, and prevention of cardiovascular conditions. Performing a genetic test for variations in the gene may help identify people as well as their families who are at a greater risk of heart disease, which enables risk identification and timely intervention. . This article investigates the applications of genetic biomarkers in cardiac disorders such as coronary artery disease, hypertension, arrhythmias, cardiomyopathy, and heart failure, with an emphasis on individual genes and their effects on mutation.

APOA1/C3/A4/A5 Gene Cluster at 11q23.3 and Lipid Metabolism Disorders: From Epigenetic Mechanisms to Clinical Practices

The APOA1/C3/A4/A5 cluster is an essential component in regulating lipoprotein metabolism and maintaining plasma lipid homeostasis. A genome-wide association analysis and Mendelian randomization have revealed potential associations between genetic variants within this cluster and lipid metabolism disorders, including hyperlipidemia and cardiovascular events. An enhanced understanding of the complexity of gene regulation has led to growing recognition regarding the role of epigenetic variation in modulating APOA1/C3/A4/A5 gene expression. Intensive research into the epigenetic regulatory patterns of the APOA1/C3/A4/A5 cluster will help increase our understanding of the pathogenesis of lipid metabolism disorders and facilitate the development of new therapeutic approaches. This review discusses the biology of how the APOA1/C3/A4/A5 cluster affects circulating lipoproteins and the current progress in the epigenetic regulation of the APOA1/C3/A4/A5 cluster.

Associations between birth weight and adult apolipoproteins: The LifeGene cohort

BACKGROUND

Early life factors may predict cardiovascular disease (CVD), but the pathways are still unclear. There is emerging evidence of an association of early life factors with apolipoproteins, which are linked to CVD. The study objective was to assess the associations between birth variables and adult apolipoproteins (apoA1 and apoB, and their ratio) in a population-based cohort.

METHODS

The LifeGene Study is a prospective cohort comprising index participants randomly sampled from the general population. Blood samples were collected between 2009 and 2016. In this sub-study, we used birth variables, obtained from a national registry for all participants born 1973 or later, including birth weight and gestational age, while adult CVD risk factors included age, sex, body mass index (BMI), lipids, and smoking history. We employed univariate and multivariate general linear regression to explore associations between birth variables, lipid levels and other adult CVD risk factors. The outcomes included non-fasting apoA1 and apoB and their ratio, as well as total cholesterol and triglycerides. A total of 10,093 participants with both birth information and lipoprotein levels at screening were included. Of these, nearly 42.5% were men (n = 4292) and 57.5% were women (n = 5801).

RESULTS

The mean (standard deviation) age of men was 30.2 (5.7) years, and for women 28.9 (5.8) years. There was an increase of 0.022 g/L in apoA1 levels per 1 kg increase in birth weight (p = 0.005) after adjusting for age, sex, BMI, gestational age, and smoking history. Similarly, there was a decrease of 0.023 g/L in apoB levels per 1 kg increase in birth weight (p<0.001) after adjusting for the same variables. There were inverse associations of birth weight with the apoB/apoA1 ratio. No independent association was found with total cholesterol, but with triglyceride levels (ẞ-coefficient (95% Confidence Interval); -0.067 (-0.114, -0.021); p-value 0.005).

CONCLUSIONS

Lower birth weight was associated with an adverse adult apolipoprotein pattern, i.e., a higher apoB/apoA1 ratio, indicating increased risk of future CVD manifestations. The study highlights the need of preconception care and pregnancy interventions that aim at improving maternal and child outcomes with long-term impacts for prevention of cardiovascular disease by influencing lipid levels.

Complex changes in serum protein levels in COVID-19 convalescents

The COVID-19 pandemic, triggered by severe acute respiratory syndrome coronavirus 2, has affected millions of people worldwide. Much research has been dedicated to our understanding of COVID-19 disease heterogeneity and severity, but less is known about recovery associated changes. To address this gap in knowledge, we quantified the proteome from serum samples from 29 COVID-19 convalescents and 29 age-, race-, and sex-matched healthy controls. Samples were acquired within the first months of the pandemic. Many proteins from pathways known to change during acute COVID-19 illness, such as from the complement cascade, coagulation system, inflammation and adaptive immune system, had returned to levels seen in healthy controls. In comparison, we identified 22 and 15 proteins with significantly elevated and lowered levels, respectively, amongst COVID-19 convalescents compared to healthy controls. Some of the changes were similar to those observed for the acute phase of the disease, i.e. elevated levels of proteins from hemolysis, the adaptive immune systems, and inflammation. In contrast, some alterations opposed those in the acute phase, e.g. elevated levels of CETP and APOA1 which function in lipid/cholesterol metabolism, and decreased levels of proteins from the complement cascade (e.g. C1R, C1S, and VWF), the coagulation system (e.g. THBS1 and VWF), and the regulation of the actin cytoskeleton (e.g. PFN1 and CFL1) amongst COVID-19 convalescents. We speculate that some of these shifts might originate from a transient decrease in platelet counts upon recovery from the disease. Finally, we observed race-specific changes, e.g. with respect to immunoglobulins and proteins related to cholesterol metabolism.

Apolipoprotein E, a Crucial Cellular Protein in the Lifecycle of Hepatitis Viruses

Apolipoprotein E (ApoE) is a multifunctional protein expressed in several tissues, including those of the liver. This lipoprotein component is responsible for maintaining lipid content homeostasis at the plasma and tissue levels by transporting lipids between the liver and peripheral tissues. The ability of ApoE to interact with host-cell surface receptors and its involvement in several cellular pathways raised questions about the hijacking of ApoE by hepatotropic viruses. Hepatitis C virus (HCV) was the first hepatitis virus reported to be dependent on ApoE for the completion of its lifecycle, with ApoE being part of the viral particle, mediating its entry into host cells and contributing to viral morphogenesis. Recent studies of the hepatitis B virus (HBV) lifecycle have revealed that this virus and its subviral envelope particles also incorporate ApoE. ApoE favors HBV entry and is crucial for the morphogenesis of infectious particles, through its interaction with HBV envelope glycoproteins. This review summarizes the data highlighting the crucial role of ApoE in the lifecycles of HBV and HCV and discusses its potential role in the lifecycle of other hepatotropic viruses.