Single-cell RNA sequencing reveals the transcriptional heterogeneity of Tbx18-positive cardiac cells during heart development.

The T-box family transcription factor 18 (Tbx18) has been found to play a critical role in regulating the development of the mammalian heart during the primary stages of embryonic development while the cellular heterogeneity and landscape of Tbx18-positive (Tbx18+) cardiac cells remain incompletely characterized. Here, we analyzed prior published single-cell RNA sequencing (scRNA-seq) mouse heart data to explore the heterogeneity of Tbx18+ cardiac cell subpopulations and provide a comprehensive transcriptional landscape of Tbx18+ cardiac cells during their development. Bioinformatic analysis methods were utilized to identify the heterogeneity between cell groups. Based on the gene expression characteristics, Tbx18+ cardiac cells can be classified into a minimum of two distinct cell populations, namely fibroblast-like cells and cardiomyocytes. In terms of temporal heterogeneity, these cells exhibit three developmental stages, namely the MEM stage, ML_P0 stage, and P stage Tbx18+ cardiac cells. Furthermore, Tbx18+ cardiac cells encompass several cell types, including cardiac progenitor-like cells, cardiomyocytes, and epicardial/stromal cells, as determined by specific transcriptional regulatory networks. The scRNA-seq results revealed the involvement of extracellular matrix (ECM) signals and epicardial epithelial-to-mesenchymal transition (EMT) in the development of Tbx18+ cardiac cells. The utilization of a lineage-tracing model served to validate the crucial function of Tbx18 in the differentiation of cardiac cells. Consequently, these findings offer a comprehensive depiction of the cellular heterogeneity within Tbx18+ cardiac cells.

Integrated analysis reveals ceRNA network of cardiac remodeling by SGLT2 inhibitor in middle-aged hypertensive rats.

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) represent an innovative class of antidiabetic agents that have demonstrated promise in mitigating cardiac remodeling. However, the transcriptional regulatory mechanisms underpinning their impact on blood pressure and the reversal of hypertension-induced cardiac remodeling remain largely unexplored. Given this context, our study concentrated on comparing the cardiac expression profiles of lncRNAs and mRNAs between Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). To validate our results, we performed blood pressure measurements, tissue staining, and qRT-PCR. The treatment led to a significant reduction in systolic blood pressure and improved cardiac remodeling by reducing myocardial fibrosis and regulating the inflammatory response. Our examination disclosed that ventricular tissue mRNA, regulated by hypertension, was primarily concentrated in the complement and coagulation cascades and cytokine-cytokine receptor interactions. Compared with SHR, the SGLT2i treatment group was associated with myocardial contraction. Investigation into the lncRNA-mRNA regulatory network and competing endogenous RNA (ceRNA) network suggested that the potential roles of these differentially expressed (DE) lncRNAs and mRNAs were tied to processes such as collagen fibril organization, inflammatory response, and extracellular matrix (ECM) modifications. We found that the expression of Col3a1, C1qa, and lncRNA NONRATT007139.2 were altered in the SHR group and that SGLT2i treatment reversed these changes. Our results suggest that dapagliflozin effectively reverses hypertension-induced myocardial remodeling through a lncRNA-mRNA transcriptional regulatory network, with immune cell-mediated ECM deposition as a potential regulatory target. This underlines the potentiality of SGLT2i and genes related to immunity as promising targets for the treatment of hypertension.

Exploration and validation of signature genes and immune associations in septic cardiomyopathy.

An early and accurate diagnosis of septic cardiomyopathy is vital for improving the overall prognosis of sepsis. In our research, we aimed to identify signature genes and their immune connections in septic cardiomyopathy. By analyzing the mouse myocardial transcriptome from sepsis induced by cecum ligation and puncture (CLP), we identified four distinct k-means clusters. Further analysis of human myocardial datasets using Weighted Gene Co-expression Network Analysis (WGCNA) revealed a strong correlation between the MEturquoise module and septic cardiomyopathy (cor = 0.79, p < .001). Through the application of Cytoscape plug-in MCODE and comprehensive analysis, we pinpointed two signature genes, THBS1 and TIMP1. These genes demonstrated significant involvement in immune cell infiltration, as detected by CIBERSORT, and displayed promising prognostic potential as validated by external datasets. Our experimental validation confirmed the up-regulation of both THBS1 and TIMP1 in septic murine hearts, underscoring their positive association with septic cardiomyopathy.

Tbx18-positive cells-derived myofibroblasts contribute to renal interstitial fibrosis via transforming growth factor-ß signaling.

It has been demonstrated that the T-box family transcription factor 18 (Tbx18) -positive cells give rise to renal mesenchymal cells and contribute to the development of the urinary system. However, it is unclear whether Tbx18-positive cells are the origin of the myofibroblasts during renal fibrosis. The present study aimed to determine the contribution of Tbx18-positive cells in kidney fibrosis and their underlying mechanism. We show that Tbx18-positive cells contribute to the development of the urinary system, especially renal fibroblasts. Following unilateral ureteral obstruction (UUO), genetic fate tracing results demonstrated that Tbx18-positive cells not only proliferate but also expand and differentiate into fibroblasts and myofibroblasts, indicating that they may act as profibrotic progenitors. Cell culture results suggest that transforming growth factor (TGF)-ß promotes Tbx18-positive cells differentiation into myofibroblasts and assist their contribution to kidney fibrosis. Overall, the present study demonstrated that Tbx18-positive cells may act as profibrotic progenitor cells in a pathological condition of UUO-induced injury. Moreover, TGF-ß may play a role in differentiation of Tbx18-positive cells into myofibroblasts in kidney fibrosis. These findings may provide a potential target on Tbx18-positive myofibroblast progenitors in the treatment of renal fibrosis.

Agrin Yes-associated Protein Promotes the Proliferation of Epicardial Cells.

ABSTRACT: Embryonic epicardial cells make an important contribution to cardiac development. However, their proliferation mechanism is still unclear. Epicardial cells from E12.5 fetal hearts were used in our study. Agrin was used to treat these cells. The expression of Aurora B, Ki67, and pH3 was measured by quantitative reverse transcription-polymerase chain reaction and immunofluorescence. The proportion of cells in G1/S/G2 phase was determined by flow cytometry. The results showed that agrin significantly increased the expression of ki67, pH3, and Aurora B in epicardial cells. Flow cytometry results showed that agrin significantly increased the proportion of epicardial cells in S phase. However, blocking yes-associated protein significantly downregulated the levels of ki67, pH3, and Aurora B and the proportion of epicardial cells in S phase. Thus, our results suggest that agrin may promote the proliferation of epicardial cells by regulating the yes-associated protein activity. This may be useful in exploring heart development mechanisms and preventing congenital heart disease.

Autophagy is involved in the differentiation of epicardial progenitor cells into vascular smooth muscle cells in mice.

Most coronary smooth muscle cells(CoSMCs) are differentiated from epicardial progenitor cells(EPCs), but the specific mechanism is not fully investigated. Previous studies have shown that autophagy plays an important role for smooth muscle cells(SMCs) differentiation, yet whether autophagy is involved in the differentiation of EPCs into CoSMCs remains unclear. In the present study, We first isolated and cultured EPCs and continuously cultured them for 72 h. Then the autophagy induction and inhibition experiment was established by using the autophagy inducer Rapamycin(RAPA) and the inhibitor 3-Methyladenine(3-MA). And further animal experiments were conducted to observe the effects of autophagy on the development of coronary arteries. Our data showed that autophagy occurred in the differentiation of EPCs into SMCs. Over activation of autophagy may lead to early transient differentiation of EPCs, enhanced migration ability and weakened systolic function, but overall, CoSMC development is still inhibited. However, inhibition of autophagy may delay the differentiation of EPCs, thus reducing the number of coronary arteries. Together, all these processes indicate that autophagy may regulate the differentiation of EPCs into CoSMCs by affecting the time point of differentiation, and appropriate autophagy intensity is required during the development of CoSMCs.

Triiodothyronine promotes the proliferation of epicardial progenitor cells through the MAPK/ERK pathway.

Thyroid hormone has important functions in the development and physiological function of the heart. The aim of this study was to determine whether 3,5,3'-Triiodothyronine (T3) can promote the proliferation of epicardial progenitor cells (EPCs) and to investigate the potential underlying mechanism. Our results showed that T3 significantly promoted the proliferation of EPCs in a concentration- and time-dependent manner. The thyroid hormone nuclear receptor inhibitor bisphenol A (100 µmol/L) did not affect T3's ability to induce proliferation. Further studies showed that the mRNA expression levels of mitogen-activated protein kinase 1 (MAPK1), MAPK3, and Ki67 in EPCs in the T3 group (10 nmol/L) increased 2.9-, 3-, and 4.1-fold, respectively, compared with those in the control group (P < 0.05). In addition, the mRNA expression of the cell cycle protein cyclin D1 in the T3 group increased approximately 2-fold compared with the control group (P < 0.05), and there were more EPCs in the S phase of the cell cycle (20.6% vs. 12.0%, P < 0.05). The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway inhibitor U0126 (10 µmol/L) significantly inhibited the ability of T3 to promote the proliferation of EPCs and to alter cell cycle progression. This study suggested that T3 significantly promotes the proliferation of EPCs, and this effect may be achieved through activation of the MAPK/ERK signaling pathway.

Age-dependent down-regulation of hyperpolarization-activated cyclic nucleotide-gated channel 4 causes deterioration of canine sinoatrial node function.

The activity of pacemaker cells in the sinoatrial node (SAN) is an indicator of normal sinus rhythm. Clinical studies have revealed that the dysfunction of the SAN progressively increases with aging. In this study, we determined the changes in hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) expression and the relationship between aging and canine SAN dysfunction. The results of cardiac electrophysiological determination revealed that the intrinsic heart rate decreased from 168 ± 11 beats min-1 in young canines to 120 ± 9 beats min-1 in adults and to 88 ± 9 beats min-1 in aged canines. The sinus node recovery time (SNRT) increased from 412 ± 32 ms in young canines to 620 ± 56 ms in adults and to 838 ± 120 ms in aged canines. Corrected SNRT (CSNRT) increased from 55 ± 12 ms in young canines to 117 ± 27 ms in adults and to 171 ± 37 ms in aged canines. These results indicated that SAN function deteriorated with aging in the canine heart. However, histological staining illustrated that fibrosis was not significantly increased with aging in canine SAN. Real-time polymerase chain reaction indicated that the expression of HCN4 mRNA was downregulated in the elderly canine SAN. Similarly, we also verified that HCN4 protein expression within the SAN declined with aging via immunofluorescence staining and western blot analysis. Taken together, our data show that electrical remodeling, related to the down-regulation of HCN4, is responsible for the gradually increased incidence of SAN dysfunction with aging. Our results provide further evidence for explaining the mechanisms of age-related deterioration in the SAN.

Biological characteristics of embryonic epicardial cells in vitro correlate with embryonic day.

The epicardial cell (EpiC) culture system plays an important role in investigating the specific mechanisms and signaling molecules that are involved in the development of EpiCs. From this early formation until adulthood, EpiCs undergo dynamic changes in the expression of embryonic genes that correlate with changes in the embryonic EpiC properties. The differences of embryonic EpiC properties may affect the related results of experiments in which EpiC culture system is used; however, these differences have not been explored. Therefore, in this study we examined the differences in the biological characteristics of EpiCs on different embryonic days in vitro EpiCs were isolated from embryonic ventricle explants on embryonic day (E) 11.5, E13.5, and E15.5. The differences in the migration, proliferation and differentiation were studied in EpiCs of different embryonic day by scratch assay, cell cycle analysis and platelet derived growth factor-bb (PDGF-BB) treatment. The results showed that EpiCs were successfully cultured from E11.5, E13.5, and E15.5 embryonic ventricle explants. The time windows of E11.5, E13.5, and E15.5 EpiC isolation out of the explants were different. The migration abilities of E11.5, E13.5, and E15.5 EpiCs decreased during embryonic development. Smooth muscle cell differentiation potential of early stage EpiCs was better than that of the later stage EpiCs. Although the proliferation ability of E11.5 EpiCs was significantly weaker than those of E13.5 and E15.5 EpiCs, the proliferation abilities of E13.5 and E15.5 EpiCs did not differ. These results suggest that the biological characteristics of EpiCs correlate with the timing of embryonic development, and different embryonic stage of ventricle should be properly chosen for culturing EpiCs depending on the purposes of the specific experiments.

Angiotensin â ¡ induces the differentiation of mouse epicardial progenitor cells into vascular smooth muscle-like cells.

Epicardial progenitor cells (EpiCs) have a crucial role in cardiac development and vasculature formation. Here we detected the expression of Angiotensin II (Ang II) receptors AT1 and AT2 on EpiCs and demonstrated that AngII could increase the expression of smooth muscle specific markers, including α-smooth muscle actin (α-SMA) and myosin heavy chain 11 (Myh11) in EpiCs. Moreover, the expression of α-SMA and Myh11 induced by Ang II was blocked by pretreatment of EpiCs with the AT1 receptor antagonist losartan, but not the AT2 receptor antagonist PD123319. We further showed that the AngII-induced cells showed significant contractile responses to carbachol. These results implied that AngII could effectively induce EpiCs to differentiate into vascular smooth muscle-like cells through the AT1 receptor.

The impact of sperm-expressed transcription factors on fate-mapping models.

Genetic lineage tracing has been used extensively in developmental biology. Many transcription factors expressed in sperm may induce Cre-mediated loxP recombination during early zygote development. In this study, we investigated the effect of sperm-expressed Cre on cell type-specific Cre-mediated loxP recombination in fate-mapping models of Tbx18+ progenitor cells. We found the recombination frequency in a reverse mating (RM) lineage was inconsistent with a normal Mendelian distribution. However, the recombination frequency in a positive mating (PM) lineage agreed with a Mendelian distribution. In the PM lineage, LacZ and EYFP were expressed in specific locations, such as the limb buds, heart, and hair follicles. Therefore, the reporter genes accurately and reliably traced cell differentiation in the PM lineage. In contrast, EYFP and LacZ were expressed throughout the embryo in the RM lineage. Thus, the reporter genes did not trace cell differentiation specifically in the RM lineage. Furthermore, Tbx18 mRNA and protein were expressed in the testicles of male mice, but almost no Tbx18 expression was detected in the ovaries of female mice. Similarly, reporter genes and Tbx18 were coexpressed in the seminiferous tubules and sperm cells of testicles. These results revealed that Cre-loxP-mediated pre-recombination in zygotes is due to Tbx18 expressed in testicle sperm cells when Cre is transmitted paternally. Our results indicate that Cre-mediated specific recombination in fate-mapping models of sperm-expressed genes may be influenced by the paternal origin of Cre. Therefore, a careful experimental design is critical when using the Cre-loxP system to trace spatial, temporal or tissue-specific fates.

Spironolactone Regulates HCN Protein Expression Through Micro-RNA-1 in Rats With Myocardial Infarction.

Emerging evidence has shown that aldosterone blockers reduced the incidence of ventricular arrhythmias in patients with myocardial infarction (MI). However, the mechanism remains unknown. In this study, we investigated the mechanism by which spironolactone, a classic aldosterone blocker, regulates hyperpolarization-activated cyclic nucleotide-gated channel (HCN) protein expression in ischemic rat myocardium after MI. Eighteen rats surviving 24 hours after MI were randomly assigned into 3 groups: MI, spironolactone, and spironolactone + antagomir-1. Six sham-operated rats had a suture loosely tied around the left coronary artery, without ligation. The border zone of the myocardial infarct was collected from each rat at 1 week after MI. HCN2 and HCN4 protein and messenger RNA (mRNA) level were measured in addition to miRNA-1 levels. Spironolactone significantly increased miRNA-1 levels and downregulated HCN2 and HCN4 protein and mRNA levels. miRNA-1 suppression with antagomir-1 increased HCN2 and HCN4 protein levels; however, HCN2 and HCN4 mRNA levels were not affected. These results suggested that spironolactone could increase miRNA-1 expression in ischemic rat myocardium after MI and that the upregulation of miRNA-1 expression partially contributed to the posttranscriptional repression of HCN protein expression, which may contribute to the effect of spironolactone to reduce the incidence of MI-associated ventricular arrhythmias.

The roles of B cells in cardiovascular diseases.

Damage to the heart can start the repair process and cause cardiac remodeling. B cells play an important role in this process. B cells are recruited to the injured place and activate cardiac remodeling through secreting antibodies and cytokines. Different types of B cells showed specific functions in the heart. Among all types of B cells, heart-associated B cells play a vital role in the heart by secreting TGFß1. B cells participate in the activation of fibroblasts and promote cardiac fibrosis. Four subtypes of B cells in the heart revealed the relationship between the B cells' heterogeneity and cardiac remodeling. Many cardiovascular diseases like atherosclerosis, heart failure (HF), hypertension, myocardial infarction (MI), and dilated cardiomyopathy (DCM) are related to B cells. The primary mechanisms of these B cell-related activities will be discussed in this review, which may also suggest potential novel therapeutic targets.

Additional use of an aldosterone antagonist in patients with mild to moderate chronic heart failure: a systematic review and meta-analysis.

AIMS: Aldosterone antagonists (AldoAs) have been used to treat severe chronic heart failure (CHF). There is uncertainty regarding the efficacy of using AldoAs in mild to moderate CHF with New York Heart Association (NYHA) classifications of I to II. This study summarizes the evidence for the efficacy of spironolactone (SP), eplerenone (EP) and canrenone in mild to moderate CHF patients. METHODS: PubMed, MEDLINE, EMBASE and OVID databases were searched before June 2012 for randomized and quasi-randomized controlled trials assessing AldoA treatment in CHF patients with NYHA classes I to II. Data concerning the study's design, patients' characteristics and outcomes were extracted. Risk ratio (RR) and weighted mean differences (WMD) or standardized mean difference were calculated using either fixed or random effects models. RESULTS: Eight trials involving 3929 CHF patients were included. AldoAs were superior to the control in all cause mortality (RR 0.79, 95% CI 0.66, 0.95) and in re-hospitalization for cardiac causes (RR 0.62, 95% CI 0.52, 0.74), the left ventricular ejection fraction was improved by AldoA treatment (WMD 2.94%, P = 0.52). Moreover, AldoA therapy decreased the left ventricular end-diastolic volume (WMD -14.04 ml, P < 0.00001), the left ventricular end-systolic volume (WMD -14.09 ml, P < 0.00001). A stratified analysis showed a statistical superiority in the benefits of SP over EP in reducing LVEDV and LVESV. AldoAs reduced B-type natriuretic peptide concentrations (WMD -37.76 pg ml(-1), P < 0.00001), increased serum creatinine (WMD 8.69 µmol l(-1), P = 0.0003) and occurrence of hyperkalaemia (RR 1.78, 95% CI 1.43, 2.23). CONCLUSIONS: Additional use of AldoAs in CHF patients may decrease mortality and re-hospitalization for cardiac reasons, improve cardiac function and simultaneously ameliorate LV reverse remodelling.

Statins therapy can reduce the risk of atrial fibrillation in patients with acute coronary syndrome: a meta-analysis.

BACKGROUND: It is a controversy whether statins therapy could be beneficial for the occurrence of atrial fibrillation (AF) in acute coronary syndrome (ACS). To clarify this problem, we performed a meta-analysis with the currently published literatures. METHODS: The electronic databases were searched to obtain relevant trials which met the inclusion criteria through October 2011. Two authors independently read the trials and extracted the related information from the included studies. Either fixed-effects models or random-effects models were assumed to calculate the overall combined risk estimates according to I(2 )statistic. Sensitivity analysis was conducted by omitting one study in each turn, and publication bias was evaluated using Begg's and Egger's test. RESULTS: Six studies were eligible to inclusion criteria, of the six studies, 161305 patients were included in this meta-analysis, 77920 (48.31%) patients had taken the statins therapy, 83385 (51.69%) patients had taken non-statins therapy. Four studies had investigated the effect of statins therapy on occurrence of new-onset AF in ACS patients, another two had described the association between statins therapy and occurrence of AF in ACS patients with AF in baseline. The occurrence of AF was reduced 35% in statins therapy group compared to that in non-statins group (95% confident interval: 0.55-0.77, P<0.0001), and the effect of statins therapy seemed more beneficial for new-onset AF (RR=0.59, 95%CI: 0.48-0.73, p=0.096) than secondary prevention of AF (RR=0.70, 95%CI: 0.43-1.14, p=0.085). There was no publication bias according to the Begg's and Egger's test (Begg, p=0.71; Egger, p=0.73). CONCLUSION: Statins therapy could reduce the risk of atrial fibrillation in patients with ACS.

Sinus node dysfunction and atrial fibrillation-Relationships, clinical phenotypes, new mechanisms, and treatment approaches.

Although the anatomical basis of the pathogenesis of sinus node dysfunction (SND) and atrial fibrillation (AF) is located primarily in the left and right atria, increasing evidence suggests a strong correlation between SND and AF, in terms of both clinical presentation and formation mechanisms. However, the exact mechanisms underlying this association are unclear. The relationship between SND and AF may not be causal, but is likely to involve common factors and mechanisms, including ion channel remodeling, gap junction abnormalities, structural remodeling, genetic mutations, neuromodulation abnormalities, the effects of adenosine on cardiomyocytes, oxidative stress, and viral infections. Ion channel remodeling manifests primarily as alterations in the "funny" current (If) and Ca2+ clock associated with cardiomyocyte autoregulation, and gap junction abnormalities are manifested primarily as decreased expression of connexins (Cxs) mediating electrical impulse propagation in cardiomyocytes. Structural remodeling refers primarily to fibrosis and cardiac amyloidosis (CA). Some genetic mutations can also cause arrhythmias, such as SCN5A, HCN4, EMD, and PITX2. The intrinsic cardiac autonomic nervous system (ICANS), a regulator of the heart's physiological functions, triggers arrhythmias.In addition, we discuss arrhythmias caused by viral infections, notably Coronavirus Disease 2019 (COVID-19). Similarly to upstream treatments for atrial cardiomyopathy such as alleviating CA, ganglionated plexus (GP) ablation acts on the common mechanisms between SND and AF, thus achieving a dual therapeutic effect.

Dapagliflozin attenuates myocardial remodeling in hypertension by activating the circadian rhythm signaling pathway.

Sodium-glucose cotransporter 2 inhibitor (SGLT2i) is a new kind of antidiabetic drug which has shown beneficial effects in reducing heart failure-related hospitalization and cardiovascular-related mortality. The mechanisms are complicated. Our study aimed to investigate the effects of dapagliflozin on the myocardium of spontaneously hypertensive rats (SHRs) without heart failure. Wistar-Kyoto rats were used as normal controls. SHRs were randomly divided into the SHR group and the -treated group. After 8 weeks of dapagliflozin treatment, the morphology of heart tissues was examined. The mRNA expression profiles were identified via RNA sequencing (RNA-Seq). Various analysis methods were used to find the differentially expressed genes (DEGs) to predict gene function and coexpression. After dapagliflozin treatment, systolic blood pressure was significantly reduced compared with that in the SHR group. Myocardial remodeling was ameliorated compared with that in the SHR group. After dapagliflozin intervention, 75 DEGs (|log2-fold change | > 0 and Q value < 0.05) were identified in the heart tissues compared to the SHR group. Quantitative real-time PCR analysis confirmed that the expression of the circadian rhythm genes Per3, Bhlhe41, and Nr1d1 was significantly upregulated, while the results were coincident with the RNA-Seq results. Dapagliflozin may effectively inhibit myocardial remodeling and regulate blood pressure. The mechanisms may be related to the activation of the circadian rhythm signaling pathway.

Single-cell and spatial transcriptomics: Advances in heart development and disease applications.

Current transcriptomics technologies, including bulk RNA-seq, single-cell RNA sequencing (scRNA-seq), single-nucleus RNA-sequencing (snRNA-seq), and spatial transcriptomics (ST), provide novel insights into the spatial and temporal dynamics of gene expression during cardiac development and disease processes. Cardiac development is a highly sophisticated process involving the regulation of numerous key genes and signaling pathways at specific anatomical sites and developmental stages. Exploring the cell biological mechanisms involved in cardiogenesis also contributes to congenital heart disease research. Meanwhile, the severity of distinct heart diseases, such as coronary heart disease, valvular disease, cardiomyopathy, and heart failure, is associated with cellular transcriptional heterogeneity and phenotypic alteration. Integrating transcriptomic technologies in the clinical diagnosis and treatment of heart diseases will aid in advancing precision medicine. In this review, we summarize applications of scRNA-seq and ST in the cardiac field, including organogenesis and clinical diseases, and provide insights into the promise of single-cell and spatial transcriptomics in translational research and precision medicine.

RNA-Seq transcriptomic landscape profiling of spontaneously hypertensive rats treated with a sodium-glucose cotransporter 2 (SGLT2) inhibitor.

BACKGROUND: Sodium-glucose co-transporter-2 inhibitor (SGLT2i) are antihyperglycemic medications that reduce cardiovascular disease (CVD) and improve chronic kidney disease prognosis in patients with diabetes mellitus. The specific impact of SGLT2i treatment on hypertensive individuals, however, remains to be established. This underscores the need for systematic efforts to profile the molecular landscape associated with SGLT2i administration. METHODS: We conducted a detailed RNA-sequencing (RNA-Seq)-based exploration of transcriptomic changes in response to empagliflozin in eight different tissues (i.e., atrium, aorta, ventricle, white adipose, brown adipose, kidney, lung, and brain) from a male rat model of spontaneously hypertension. Corresponding computational analyses (i.e., clustering, differentially-expressed genes [DEG], and functional association) were performed to analyze these data. Blood pressure measurements, tissue staining studies and RT-qPCR were performed to validate our in silico findings. RESULTS: We discovered that empagliflozin exerted potent transcriptomic effects on various tissues, most notably the kidney, white adipose, and lung in spontaneously hypertension rats (SHR). The functional enrichment of DEGs indicated that empagliflozin may regulate blood pressure, blood glucose and lipid homeostasis in SHR. Consistent with our RNA-Seq findings, immunohistochemistry and qPCR analyses revealed decreased renal expression of mitogen-activated protein kinase 10 (MAPK10) and decreased pulmonary expression of the proinflammatory factors Legumain and cathepsin S (CTSS) at 1 month of empagliflozin administration. Notably, immunofluorescence experiments showed increased expression of the AMP-activated protein kinases Prkaa1 and Prkaa2 in white adipose tissue of SHR following empagliflozin therapy. Furthermore, the transcriptomic signatures of the blood pressure-lowing effect by empagliflozin were experimentally validated in SHR. CONCLUSIONS: This study provided an important resource of the effects of empagliflozin on various tissues of SHRs. We identified tissue-specific and tissue-enriched transcriptomic signatures, and uncovered the beneficial effects of empagliflozin on hypertension, weight gain and inflammatory response in validated experiments.

RNA-Seq transcriptome analysis of renal tissue from spontaneously hypertensive rats revealed renal protective effects of dapagliflozin, an inhibitor of sodium-glucose cotransporter 2.

Hypertensive nephropathy (HTN) is a common complication of hypertension. Although various agents for treatment of hypertension exert significant effects, there is currently no effective treatment for hypertensive nephropathy. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, such as dapagliflozin (DAPA), are a new class of hypoglycemic agents shown to improve the prognosis of patients with chronic kidney disease and diabetes mellitus. However, the mechanisms underlying the protective effects of DAPA remain unclear. RNA-sequencing (RNA-Seq)-based computational analysis was conducted to explore the transcriptomic changes to spontaneously hypertensive rats (SHRs) treated with DAPA for 8 weeks. Differentially expressed genes in SHRs were related to dysregulation of lipid metabolism, oxidation-reduction reaction, immunity and inflammation in HTN. Transcriptome analysis showed that 8 weeks of DAPA therapy exerted protective effects on the renal tissues of SHRs through the lysosomal, phagosomal, and autophagic pathways. VENN diagram analysis identified Zinc finger and BTB domain-containing 20 (Zbtb20) as the potential target of DAPA therapy. Consistent with the RNA-Seq findings, real-time quantitative PCR and immunohistochemical analyses revealed increased expression of Zbtb20 in the renal tissues of SHRs, whereas expression was decreased following 8 weeks of DAPA administration. The results of this study clarified the transcriptome signature of HTN and the beneficial effects of DAPA on renal tissues by alleviating dysregulation of metabolic processes and reducing inflammation.