Abstract
The inflammatory response after myocardial infarction (MI) is a precisely regulated process that greatly affects subsequent wound healing and remodeling. However, the understood about the process are still limited. Macrophages are critically involved in inflammation resolution after MI. Krüppel-like factor 9 (Klf9) is a C2H2 zinc finger-containing transcription factor that has been implicated in glucocorticoid regulation of macrophages. However, the contribution of Klf9 to macrophage phenotype and function in the context of MI remains unclear. Our study revealed that KLF9 deficiency results in higher mortality and cardiac rupture rate, as well as a considerable exacerbation in cardiac function. Single-cell RNA sequencing and flow cytometry analyses reveals that, compared to WT mice, Klf9-/- mice display excessive neutrophil infiltration, insufficient macrophage infiltration, and a reduced proportion of Monocyte-derived CD206+ macrophages post-MI. Moreover, the expression of IFN-γ-STAT1 pathway genes in Klf9-/- cardiac macrophages is dysregulated, characterized by insufficient expression at 1 day post-MI and excessive expression at day 3 post-MI. Mechanistically, Klf9 directly binds to the promoters of Stat1 gene, regulating its transcription. Overall, these findings indicates that Klf9 beneficially influences wound healing after MI through modulating macrophage recruitment and differentiation by regulating the IFN-γ-STAT1 signal pathway.
Authors
Sheng Xu, Hao Li, Jun Han, Yawei Xu, Niannian Li, Wenliang Che, Feng Liu, Wenhui Yue
Abstract
RESULTS. Participants with CAD (n = 723) had 12% higher mean relative levels of nHDLox compared with those with invasively excluded CAD (n = 502, P < 0.001). Patients presenting with symptoms of an ACS had the highest nHDLox values when compared with the elective cohort (median 1.35, IQR 0.97 to 1.85, P < 0.001). In multivariate analysis adjusted for age, sex, body mass index, and hypertension, nHDLox was a strong independent predictor of ACS (P < 0.001) but not of CAD (P > 0.05).CONCLUSION. HDL antioxidant function is reduced in patients with CAD. nHDLox is strongly associated with ACS. TRIAL REGISTRATION. German Clinical Trials Register DRKS00014037. FUNDING. Brandenburg Medical School Theodor Fontane, the BIOX Stiftung, and NIH grants R01AG059501 and R03AG059462. BACKGROUND. High-density lipoprotein (HDL) function rather than its concentration plays an important role in the pathogenesis of coronary artery disease (CAD). The aim of the present study was to determine whether reduced antioxidant function of HDL is associated with the presence of a stable CAD or acute coronary syndrome (ACS).METHODS. HDL function was measured in 2 cohorts: 1225 patients admitted electively for coronary angiography and 196 patients with ACS. A validated cell-free biochemical assay was used to determine reduced HDL antioxidant function, as assessed by increased HDL-lipid peroxide content (HDLox), which was normalized by HDL-C levels and the mean value of a pooled serum control from healthy participants (nHDLox; unitless). Results are expressed as median with interquartile range (IQR).
Authors
Benjamin Sasko, Linda Scharow, Rhea Mueller, Monique Jaensch, Werner Dammermann, Felix S. Seibert, Philipp Hillmeister, Ivo Buschmann, Martin Christ, Oliver Ritter, Nazha Hamdani, Christian Ukena, Timm H. Westhoff, Theodoros Kelesidis, Nikolaos Pagonas
Abstract
Inflammation is a critical pathological process in myocardial infarction. Although immunosuppressive therapies can mitigate inflammatory responses and improve outcomes in myocardial infarction, they also increase the risk of infections. Identifying novel regulators of local cardiac inflammation could provide safer therapeutic targets for myocardial ischemia/reperfusion injury. In this study, we identified a previously unknown micropeptide, which we named Inflammation Associated MicroPeptide (IAMP). IAMP is predominantly expressed in cardiac fibroblasts, and its expression is closely associated with cardiac inflammation. Down-regulation of IAMP promotes, whereas its overexpression prevents, the transformation of cardiac fibroblasts into a more inflammatory phenotype under stressed/stimulated conditions, as evidenced by changes in the expression and secretion of pro-inflammatory cytokines. Consequently, loss of IAMP function leads to uncontrolled inflammation and worsens cardiac injury following ischemia/reperfusion surgery. Mechanistically, IAMP promotes the degradation of HIF-1α by interacting with its stabilizing partner HSP90, and thus suppresses the transcription of pro-inflammatory genes downstream of HIF-1α. This study underscores the significance of fibroblast-mediated inflammation in cardiac ischemia/reperfusion injury and highlights the therapeutic potential of targeting micropeptides for myocardial infarction.
Authors
Youchen Yan, Tingting Zhang, Xin He, Tailai Du, Gang Dai, Xingfeng Xu, Zhuohui chen, Jialing Wu, Huimin Zhou, Yazhi Peng, Yan Li, Chen Liu, Xinxue Liao, Yugang Dong, Jing-song Ou, Zhan-Peng Huang
Abstract
Authors
Juliane Schwanbeck, Max Stahnke, Anna Eberlein, Madeleine Goeritzer, Arndt Schulze, Dominique Pernitsch, Dagmar Kolb, Gernot F. Grabner, Theda U.P. Bartolomaeus, Sofia K. Forslund, Holger Gerhardt, Gabriele G. Schiattarella, Lucia Cocera Ortega, Natalia López-Anguita, Erin E. Kershaw, Henrike Maatz, Norbert Hübner, Rudolf Zechner, Anna Foryst-Ludwig, Ulrich Kintscher
Abstract
This study examined the involvement of fibroblast growth factor-23 (FGF-23) in primary aldosteronism (PA), a condition characterized by elevated aldosterone levels and hypertension. We recruited patients with unilateral PA (uPA) and observed increased levels of C-terminal FGF-23 (cFGF-23) and C-terminal to intact FGF-23 (iFGF-23) in patients with uPA compared with essential hypertension control participants. Elevated preoperative cFGF-23 levels were associated with adverse outcomes, including mortality and cardiovascular or kidney events. Plasma cFGF-23 levels demonstrated a nonlinear rise with aldosterone, but iFGF-23 levels were not correlated with plasma aldosterone concentration. Higher cFGF-23 levels independently predicted hypertension remission after adrenalectomy for patients with uPA. Patients with uPA, who exhibited elevated cFGF-23 levels, had decreased levels after adrenalectomy. In cell cultures, aldosterone enhanced cleavage of iFGF-23, leading to increased levels of cFGF-23 fragments, an effect mitigated by silencing of family with sequence similarity 20, member C (FAM20C). However, the enhancement of cFGF-23 levels remained unaffected by the furin inhibitor. The study suggests that aldosterone influences FGF-23 phosphorylation by interacting with FAM20C, with docking experiments indicating aldosterone’s binding to FAM20C. This work highlights that patients with uPA with elevated cFGF-23 levels are associated with cardiovascular risks, and adrenalectomy reduces cFGF-23. Aldosterone likely promotes cFGF-23 production through FAM20C-mediated phosphorylation of iFGF-23.
Authors
Vin-Cent Wu, Kang-Yung Peng, Tsu-I Chen, Chiao-Yin Sun, Hung-Wei Liao, Chieh-Kai Chan, Yen-Hung Lin, Hung-Hsiang Liou, Jeff S. Chueh
Abstract
Aortic dissection or rupture is a major cause of mortality in vascular Ehlers-Danlos Syndrome (vEDS), a connective tissue disorder caused by heterozygous mutations in the COL3A1 gene. C57BL6/J (BL6) mice carrying the Col3a1 G938D/+ mutation recapitulate the vEDS vascular phenotype and die suddenly of aortic rupture/dissection. However, 129S6/SvEvTac (129) mice expressing the same Col3a1 G938D/+ mutation show near-complete life-long protection from vascular rupture. To identify genetic modifiers of vascular risk in vEDS, we performed genome-wide genotyping of intercrossed BL6/129 vEDS mice stratified by survival and identified a significant protective locus encompassing a variant in Map2k6, encoding Mitogen-Activated Protein Kinase Kinase 6 (M2K6), a p38-activating kinase. Genetic ablation of Map2k6 rendered previously protected 129 vEDS mice susceptible to aortic rupture, in association with reduced protein phosphatase 1 activity and increased PKC and ERK phosphorylation. Accelerated vascular rupture in vEDS mice treated with a pharmacological inhibitor of p38 was rescued by concomitant ERK antagonism, supporting an opposing role for ERK and p38 in the modification of aortic rupture risk in vEDS. These results suggest that pharmacologic strategies aimed at mimicking the effect of this natural protective pathway may improve prevention of aortic rupture risk in vEDS.
Authors
Caitlin J. Bowen, Rebecca Sorber, Juan F. Calderon Giadrosic, Jefferson J. Doyle, Graham Rykiel, Zachary Burger, Xiaoyan Zhang, Wendy A. Espinoza Camejo, Nicole K. Anderson, Simone Sabnis, Chiara Bellini, Elena MacFarlane, Harry C. Dietz
Abstract
The hERG1 potassium channel conducts the cardiac repolarizing current, IKr. hERG1 has emerged as a therapeutic target for cardiac diseases marked by prolonged actional potential duration (APD). Unfortunately, many hERG1 activators display off-target and proarrhythmic effects that limit their therapeutic potential. A Per-Arnt-Sim (PAS) domain in the hERG1 N-terminus reduces IKr by slowing channel activation and promoting inactivation. Disrupting PAS activity increases IKr and shortens APD in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). We thus hypothesized that the hERG1 PAS domain could represent a therapeutic target to reduce arrhythmogenic potential in a long QT syndrome (LQTS) background. To test this, we measured the antiarrhythmic capacity of a PAS-disabling single-chain variable fragment antibody, scFv2.10, in a hiPSC-CM line derived from a Jervell and Lange Nielsen syndrome (JLN) patient. JLN is a severe form of LQTS caused by autosomal recessive mutations in KCNQ1. The patient in this study carried compound heterozygous mutations in KCNQ1. Corresponding JLN hiPSC-CMs displayed prolonged APD and early after depolarizations (EADs). Disrupting PAS with scFv2.10 increased IKr, shortened APD, and reduced the incidence of EADs. These data demonstrate that the hERG1 PAS domain could serve as a therapeutic target to treat disorders of cardiac electrical dysfunction.
Authors
Chiamaka U. Ukachukwu, Eric N. Jimenez-Vazquez, Shreya Salwi, Matthew Goodrich, Francisco G. Sanchez-Conde, Kate M. Orland, Abhilasha Jain, Lee L. Eckhardt, Timothy J. Kamp, David K. Jones
Abstract
African American (AA) women are disproportionally affected by obesity and hyperlipidemia, particularly in the setting of adverse social determinants of health (aSDoH) contributing to health disparities. Obesity, hyperlipidemia, and aSDoH appear to impair Natural Killer cells (NKs). As potential common underlying mechanisms are largely unknown, we sought to investigate common signaling pathways involved in NK dysfunction related to obesity and hyperlipidemia in AA women from under-resourced neighborhoods. We determined in freshly isolated NKs that obesity and measures of aSDoH are associated with a shift in NK subsets away from CD56dim/CD16+ cytotoxic NKs. Using ex vivo data, we identified LDL as a marker related to NK cell function in an AA population from under-resourced neighborhoods. Additionally, NK cells from AA women with obesity and LDL-treated NK cells displayed a loss in NK cell function. Comparative unbiased RNA sequencing analysis revealed DUSP1 as a common factor. Subsequently, chemical inhibition of DUSP1 and DUSP1 overexpression in NK cells highlighted its significance in NK cell function and lysosome biogenesis in a mTOR/TFEB-related fashion. Our data demonstrate a pathway by which obesity and hyperlipidemia in the setting of aSDoH may relate to NK dysfunction, making DUSP1 an important target for further investigation of health disparities.
Authors
Yvonne Baumer, Komudi Singh, Abhinav Saurabh, Andrew S. Baez, Cristhian A. Gutierrez-Huerta, Long Chen, Muna Igboko, Briana S. Turner, Josette A. Yeboah, Robert N. Reger, Lola R. Ortiz-Whittingham, Sahil Joshi, Marcus R. Andrews, Elizabeth M. Aquino Peterson, Christopher K.E. Bleck, Laurel G. Mendelsohn, Valerie M. Mitchell, Billy S. Collins, Neelam R. Redekar, Skyler A. Kuhn, Christian A. Combs, Mehdi Pirooznia, Pradeep K. Dagur, David S.J. Allan, Daniella Muallem-Schwartz, Richard W. Childs, Tiffany M. Powell-Wiley
Abstract
BACKGROUND Sodium-glucose cotransporter 2 inhibitors slow down progression of chronic kidney disease (CKD). We tested whether the circulating substrate mix is related to CKD progression and cardiovascular outcomes in patients with type 2 diabetes (T2D) and albuminuric CKD in the CREDENCE trial.METHODS We measured fasting substrates in 2,543 plasma samples at baseline and 1 year after randomization to either 100 mg canagliflozin or placebo and used multivariate Cox models to explore their association with CKD progression, heart failure hospitalization/cardiovascular death (hHF/CVD), and mortality.RESULTS Higher baseline lactate and free fatty acids (FFAs) were independently associated with a lower risk of CKD progression (HR = 0.73 [95% CI: 0.54–0.98] and HR = 0.67 [95% CI: 0.48–0.95], respectively) and hHF/CVD HR = 0.70 [95% CI: 0.50–0.99] and HR = 0.63 [95% CI: 0.42–0.94]). Canagliflozin led to a rise in plasma FFAs, glycerol, β-hydroxybutyrate, and acetoacetate. Changes in substrate between baseline and year 1 predicted an approximately 30% reduction in relative risk of both CKD progression and hHF/CVD independently of treatment. More patients who did not respond to canagliflozin treatment in terms of CKD progression belonged to the bottom lactate and FFA distribution tertiles.CONCLUSION In T2D patients with albuminuric CKD, basic energy substrates selectively influenced major long-term endpoints; canagliflozin treatment amplified their effects by chronically raising their circulating levels.
Authors
Ele Ferrannini, Simona Baldi, Maria Tiziana Scozzaro, Giulia Ferrannini, Michael K. Hansen
Insulin mitigates acute ischemia induced atrial fibrillation and sinoatrial node dysfunction ex vivo
Abstract
Acute atrial ischemia is a well-known cause of postoperative atrial fibrillation (POAF). However, mechanisms through which ischemia contributes to the development of POAF are not well understood. In this study, ex vivo Langendorff perfusion was used to induce acute ischemia and reperfusion in the heart in order to mimic POAF. Inducibility of atrial fibrillation (AF) was evaluated using programmed electrical stimulation and confirmed with open-atrium optical mapping. Compared to the control group without ischemia, 25 minutes of ischemia substantially increased the incidence of AF. The right atrium was more susceptible to AF than the left atrium. Administering insulin for 30 minutes before ischemia and during reperfusion with 25 minutes of ischemia greatly reduced the vulnerability to AF. However, insulin treatment during reperfusion only did not show substantial benefits against AF. Optical mapping studies showed that insulin mitigates ischemia-induced abnormal electrophysiology, including shortened action potential duration and effective refractory period, slowed conduction velocity, increased conduction heterogeneity, and altered calcium transients. In conclusion, insulin reduced the risk of acute ischemia/reperfusion-induced AF via improving the electrophysiology and calcium handling of atrial cardiomyocytes, which provides a potential therapy for POAF.
Authors
Huiliang Qiu, Fan Li, Hannah Prachyl, Alejandra Patino-Guerrero, Michael Rubart, Wuqiang Zhu
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