ABSTRACT
Long non-coding RNAs (lncRNAs) are closely implicated in biological processes and diseases with high inflammatory components. These molecules exhibit significant temporal and tissue specificity. However, the expression and function of lncRNAs have not been studied in patients after heart transplantation. Thus, we aimed to identify circulating lncRNAs in these patients and evaluate their diagnostic capacity as potential biomarkers for the non-invasive detection of acute cellular rejection (ACR). For them, we performed a transcriptomic study based on ncRNA-seq technology to detect lncRNAs in serum samples, matched to routine endomyocardial biopsies, from patients without rejection episode (0R, n = 12) and with mild (1R, n = 16) or moderate-severe (≥ 2R, n = 12) ACR. We identified 11,062 circulating lncRNAs in the serum of patients after heart transplantation. Moreover, 6 lncRNAs showed statistically significant expression when the different ACR grades were compared. Among them, AC008105.3, AC006525.1, AC011455.8, AL359220.1, and AC025279.1 had relevant diagnostic capacity for detection of ≥ 2R (AUC of 0.850 to 1.000) and 1R (AUC of 0.750 to 0.854) grades, along with high specificity and positive predictive values (≥ 83%). In addition, AL359220.1 and AC025279.1 were independent predictors for the presence of moderate-severe ACR (odds ratio = 31.132, p < 0.01 and C statistic = 0.939, p < 0.0001; odds ratio = 18.693, p < 0.05 and C statistic = 0.902, p < 0.001; respectively). In conclusion, we describe, for the first time, circulating lncRNAs after heart transplantation as potential candidates for non-invasive detection of ACR. AL359220.1 and AC025279.1 showed excellent diagnostic capability correlating with the severity episode and were strong independent predictors of rejection.
ABSTRACT
Heart failure (HF) is a disease related to bioenergetic mitochondrial abnormalities. However, the whole status of molecules involved in the oxidative phosphorylation system (OXPHOS) is unknown. Therefore, we analyzed the OXPHOS transcriptome of human cardiac tissue by RNA-seq analyses (mRNA n = 36; ncRNA n = 30) in HF patients (ischemic cardiomyopathy (ICM) and dilated cardiomyopathy (DCM)) and control subjects. We detected 28 altered genes in these patients, highlighting greater deregulation in ICM. Specifically, we found a general overexpression of complex V (ATP synthase) elements, among them, ATP5I (ICM, FC = 2.04; p < 0.01), ATP5MJ (ICM, FC = 1.33, p < 0.05), and ATP5IF1 (ICM, FC = 1.81; p < 0.001), which presented a significant correlation with established echocardiographic parameters of cardiac remodeling and ventricular function as follows: left ventricular end-systolic (p < 0.01) and end-diastolic (p < 0.01) diameters, and ejection fraction (p < 0.05). We also detected an increase in ATP5IF1 protein levels (ICM, FC = 1.75; p < 0.01) and alterations in the microRNA expression levels of miR-208b-3p (ICM, FC = -1.44, p < 0.001), miR-483-3p (ICM, FC = 1.37, p < 0.01), regulators of ATP5I. Therefore, we observed the deregulation of the OXPHOS transcriptome in ICM patients, highlighting the overexpression of complex V and its relationship with cardiac remodeling and function.
ABSTRACT
BACKGROUND: Cardiac fibroblast activation protein (FAP) has an emerging role in heart failure (HF). A paradoxical reduction in its levels in pathological conditions associated with acute processes has been observed. We aimed to identify FAP cardiac tissue expression and its relationship with the main cardiac fibrosis-related signaling pathways, and to compare plasma FAP levels in acute and chronic HF patients. METHODS: Transcriptomic changes were assessed via mRNA/ncRNA-seq in left ventricle tissue from HF patients (n = 57) and controls (n = 10). Western blotting and immunohistochemistry were used to explore FAP protein levels and localization in cardiac tissue. ELISA was performed to examine plasma FAP levels in acute HF (n = 48), chronic HF (n = 15) and control samples (n = 7). RESULTS: FAP overexpression in cardiac tissue is related to the expression of molecules directly involved in cardiac fibrosis, such as POSTN, THBS4, MFAP5, COL1A2 and COL3A1 (P < 0.001), and is directly and inversely related to pro- and antifibrotic microRNAs, respectively. The observed FAP overexpression is not reflected in plasma. Circulating FAP levels were lower in acute HF patients than in controls (P < 0.05), while chronic HF patients did not show significant changes. The clinical variables analyzed, such as functional class or etiology, do not affect plasma FAP concentrations. CONCLUSIONS: We determined that in HF cardiac tissue, FAP is related to the main cardiac fibrosis signaling pathways as well as to pro- and antifibrotic microRNAs. Additionally, an acute phase of HF decreases plasma FAP levels despite the upregulation observed in cardiac tissue and regardless of other clinical conditions.
