Hypertrophic Markers Research Articles

GQ262 Attenuates Pathological Cardiac Remodeling by Downregulating the Akt/mTOR Signaling Pathway.

Cardiac remodeling, a critical process that can lead to heart failure, is primarily characterized by cardiac hypertrophy. Studies have shown that transgenic mice with Gαq receptor blockade exhibit reduced hypertrophy under induced pressure overload. GQ262, a novel Gαq/11 inhibitor, has demonstrated good biocompatibility and specific inhibitory effects on Gαq/11 compared to other inhibitors. However, its role in cardiac remodeling remains unclear. This study aims to explore the anti-cardiac remodeling effects and mechanisms of GQ262 both in vitro and in vivo, providing data and theoretical support for its potential use in treating cardiac remodeling diseases. Cardiac hypertrophy was induced in mice via transverse aortic constriction (TAC) for 4 weeks and in H9C2 cells through phenylephrine (PE) induction, confirmed with WGA and H&E staining. We found that GQ262 improved cardiac function, inhibited the protein and mRNA expression of hypertrophy markers, and reduced the levels of apoptosis and fibrosis. Furthermore, GQ262 inhibited the Akt/mTOR signaling pathway activation induced by TAC or PE, with its therapeutic effects disappearing upon the addition of the Akt inhibitor ARQ092. These findings reveal that GQ262 inhibits cardiomyocyte hypertrophy and apoptosis through the Akt/mTOR signaling pathway, thereby reducing fibrosis levels and mitigating cardiac remodeling.

The functional role of m6A demethylase ALKBH5 in cardiomyocyte hypertrophy

Cardiomyocyte hypertrophy is a major outcome of pathological cardiac hypertrophy. The m6A demethylase ALKBH5 is reported to be associated with cardiovascular diseases, whereas the functional role of ALKBH5 in cardiomyocyte hypertrophy remains confused. We engineered Alkbh5 siRNA (siAlkbh5) and Alkbh5 overexpressing plasmid (Alkbh5 OE) to transfect cardiomyocytes. Subsequently, RNA immunoprecipitation (RIP)-qPCR, MeRIP-qPCR analysis and the dual-luciferase reporter assays were applied to elucidate the regulatory mechanism of ALKBH5 on cardiomyocyte hypertrophy. Our study identified ALKBH5 as a new contributor of cardiomyocyte hypertrophy. ALKBH5 showed upregulation in both phenylephrine (PE)-induced cardiomyocyte hypertrophic responses in vitro and transverse aortic constriction (TAC)/high fat diet (HFD)-induced pathological cardiac hypertrophy in vivo. Knockdown or overexpression of ALKBH5 regulated the occurrence of hypertrophic responses, including the increased cardiomyocyte surface areas and elevation of the hypertrophic marker levels, such as brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP). Mechanically, we indicated that ALKBH5 activated JAK2/STAT3 signaling pathway and mediated m6A demethylation on Stat3 mRNA, but not Jak2 mRNA, resulting in the phosphorylation and nuclear translocation of STAT3, which enhances the transcription of hypertrophic genes (e.g., Nppa) and ultimately leads to the emergence of cardiomyocytes hypertrophic growth. Our work highlights the functional role of ALKBH5 in regulating the onset of cardiomyocyte hypertrophy and provides a potential target for hypertrophic heart diseases prevention and treatment.ALKBH5 activated JAK2/STAT3 signaling pathway and mediated m6A demethylation on Stat3 mRNA, but not Jak2 mRNA, resulting in the phosphorylation and nuclear translocation of STAT3, which enhances the transcription of hypertrophic genes (e.g., Nppa) and ultimately leads to the emergence of cardiomyocytes hypertrophic growth.

Interleukin(IL)-37 attenuates isoproterenol (ISO)-induced cardiac hypertrophy by suppressing JAK2/STAT3-signaling associated inflammation and oxidative stress

BackgroundInflammation and oxidative stress have drawn more and more interest in the realm of cardiovascular disease. In many different disorders, IL-37 acts as an anti-inflammatory and suppressor of inflammation. This study aimed to investigate whether IL-37 could alleviate cardiac hypertrophy by reducing inflammation and oxidative stress. MethodsIn vivo, a cardiac hypertrophy model was induced by 14 d of daily isoproterenol (ISO, 30 mg/kg/d) injection, followed by weeks of treatment with recombinant human IL-37 (1000 ng/animal), administered three times weekly. Assessments concentrated on markers of inflammation and oxidative stress, apoptosis, myocardial disease, and cardiac shape and function. In vitro, neonatal rat cardiomyocytes (NRCMs) were subjected to ISO (10 µM) to establish a cardiomyocytes hypertrophy model. Subsequent IL-37 treatment (100 ng/ml) was applied to determine its cardioprotective efficacy and to elucidate further the underlying mechanisms involved. ResultsSignificant cardioprotective benefits of IL-37 were seen (in vitro as well as in vivo), primarily through the reduction of oxidative stress, inflammation, apoptosis, and heart hypertrophy markers. Furthermore, IL-37 treatment was associated with a decrease in JAK2 and STAT3 phosphorylation. It is interesting to note that WP1066, a JAK2/STAT3 inhibitor, exhibited antioxidant and anti-inflammatory properties comparable to IL-37, as well as synergistic effects when mixed with the latter. ConclusionISO-induced cardiac hypertrophy is lessened by IL-37 through the reduction of oxidative stress and inflammation. Additionally, the effects of IL-37 are closely related to inactivation of the JAK2/STAT3 signaling pathway. It is anticipated that IL-37 will one day be used to treat cardiovascular illnesses such as heart hypertrophy.

TMEM100 acts as a TAK1 receptor that prevents pathological cardiac hypertrophy progression

Pathological cardiac hypertrophy is the primary cause of heart failure, yet its underlying mechanisms remain incompletely understood. Transmembrane protein 100 (TMEM100) plays a role in various disorders, such as nervous system disease, pain and tumorigenesis, but its function in pathological cardiac hypertrophy is still unknown. In this study, we observed that TMEM100 is upregulated in cardiac hypertrophy. Functional investigations have shown that adeno-associated virus 9 (AAV9) mediated-TMEM100 overexpression mice attenuates transverse aortic constriction (TAC)-induced cardiac hypertrophy, including cardiomyocyte enlargement, cardiac fibrosis, and impaired heart structure and function. We subsequently demonstrated that adenoviral TMEM100 (AdTMEM100) mitigates phenylephrine (PE)-induced cardiomyocyte hypertrophy and downregulates the expression of cardiac hypertrophic markers in vitro, whereas TMEM100 knockdown exacerbates cardiomyocyte hypertrophy. The RNA sequences of the AdTMEM100 group and control group revealed that TMEM100 was involved in oxidative stress and the MAPK signaling pathway after PE stimulation. Mechanistically, we revealed that the transmembrane domain of TMEM100 (amino acids 53–75 and 85–107) directly interacts with the C-terminal region of TAK1 (amino acids 1–300) and inhibits the phosphorylation of TAK1 and its downstream molecules JNK and p38. TAK1-binding-defective TMEM100 failed to inhibit the activation of the TAK1-JNK/p38 pathway. Finally, the application of a TAK1 inhibitor (iTAK1) revealed that TAK1 is necessary for TMEM100-mediated cardiac hypertrophy. In summary, TMEM100 protects against pathological cardiac hypertrophy through the TAK1-JNK/p38 pathway and may serve as a promising target for the treatment of cardiac hypertrophy.

Low Thyroid Hormones Level Attenuates Mitochondrial Dysfunction and Right Ventricular Failure in Pulmonary Hypertensive Rats.

This study is to investigate the repercussions of hypothyroidism in the pathophysiological progression of pulmonary arterial hypertension (PAH). While the control (CTL, n = 5) male Wistar rats received vehicle, PAH was induced with monocrotaline (MCT group, n = 15). Hypothyroidism was induced in a subset of rats by methimazole 3weeks prior to the MCT injection (MMZ + MCT group, n = 15). Plasma thyroid hormones were measured by radioimmunoassay. Electrocardiographic, echocardiographic, and hemodynamic analyses were performed to evaluate the progression of PAH. Gene expression of antioxidant enzymes and cardiac hypertrophy markers were assessed by qPCR. Mitochondrial respiration, ATP levels, and ROS production were measured in right ventricular (RV) samples. Plasma T3 and T4 decreased in both MCT and MMZ + MCT groups (p < 0.05). Right ventricular systolic pressure (RVSP) increased, and RV - dP/dt, + dP/dt, and contractility index decreased in the MCT versus the CTL group and remained within control levels in the MMZ + MCT group (p < 0.05). Relative RV weight, RV wall thickness, RV diastolic area, and relative lung weight were augmented in the MCT versus the CTL group, whereas all parameters were improved to the CTL levels in the MMZ + MCT group (p < 0.05). Only the MCT group exhibited an increased duration of QTc interval compared to the baseline period (p < 0.05). ADP-induced mitochondrial respiration and ATP levels were decreased, and ROS production was increased in MCT versus the CTL group (p < 0.05), while the MMZ + MCT group exhibited increased mitochondrial respiration versus the MCT group (p < 0.05). Hypothyroidism attenuated the RV mitochondrial dysfunction and the pathophysiological progression of MCT-induced PAH.

Fibroblast growth factor 20 ameliorates cardiac hypertrophy via activation ErbB2

Fibroblast growth factor 20 (FGF20) is a member of the fibroblast growth factor family and involved in embryonic development and cardiac repair. This study aimed to explore the role of FGF20 in cardiac hypertrophy and the underlying molecular mechanisms. FGF20 improved cardiac hypertrophy in vivo and in vitro. Furthermore, FGF20 increased expression of erythroblastic leukemia viral oncogene homolog 2 (ErbB2), which was negatively correlated with expression of the cardiac hypertrophy markers atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). In addition, FGF20 effectively protected cardiomyocytes against apoptosis and oxidative stress. To further investigate whether protective effect of FGF20 is mediated by ErbB2, neonatal rat cardiomyocytes (NRCMs) were treated with lapatinib, an inhibitor of ErbB2. Lapatinib largely abrogated the anti-hypertrophic effect of FGF20, accompanied by increases in cardiomyocyte apoptosis and oxidative stress. In summary, this study reveals that FGF20 prevents cardiac hypertrophy by inhibiting apoptosis and oxidative stress via activating ErbB2 and may be a promising therapeutic strategy for cardiac hypertrophy.

Resistance training, skeletal muscle hypertrophy, and glucose homeostasis: how related are they? A Systematic review and Meta-analysis.

Resistance training (RT) promotes skeletal muscle (Skm) hypertrophy, increases muscular strength, and improves metabolic health. Whether changes in fat-free mass (FFM; a surrogate marker of muscle hypertrophy) moderate RT-induced improvements in glucose homeostasis has not been determined, despite extensive research on the benefits of RT for health and performance. The aim of this meta-analysis is to examine whether RT-induced Skm hypertrophy drives improvements in glucose metabolism and to explore confounders, such as biological sex and training parameters. Random-effects meta-analyses were performed using variance random effects. Meta-regressions were performed for confounding factors depending on the heterogeneity (I2). Analyses from 33 intervention studies revealed significant within-study increases in FFM with a moderate effect size (within-studies: (effect size; ES=0.24 [0.10; 0.39]; p=0.002; I2=56%) and a tendency for significance when compared with control groups (ES=0.42 [-0.04-0.88]; p=0.07). Within-study significant increases in glucose tolerance (2 h glucose: ES = -0.3 [-0.50; -0.11]; p<0.01; I2=43%; glucose area under the curve (AUC): -0.40 [-0.66; -0.13] I2=76.1%; p<0.01) and insulin sensitivity (ES=0.38 [0.13; 0.62]; I2=53.0%; p<0.01) were also apparent with RT. When compared to control groups, there was no significant difference in 2 h glucose, nor in glucose AUC from baseline in RT intervention groups. Meta-regression analyses failed to consistently reveal increases in FFM as a moderator of glucose homeostasis. Other mixed-effect models were also unsuccessful to unveil biological sex or training parameters as moderators of FFM increases and glucose homeostasis changes. Although Skm hypertrophy and improvements in glycemic control occur concurrently during RT, changes in these variables were not always related. Well-controlled trials including detailed description of training parameters are needed to inform RT guidelines for improving metabolic health. Registration and protocol number (Prospero): CRD42023397362.

Oral supplementation of inositols effectively recovered lithium-induced cardiac dysfunctions in mice

This study investigates the effects of inositol (INO) supplementation on cardiac changes caused by Li in mice. The study involved 4 groups of C57BL6 mice (n=10 each): (i) mice orally administered with Li2CO3 for 8 weeks, then 4 additional weeks without (Li_group) or (ii) with INO supplementation (Li_INOdelayed_group) (total of 12 weeks); (iii) mice given Li2CO3 and INO supplementation concurrently for 12 weeks (Li+INO_group); (iv) one group left untreated (C–group). The INO was administered as a mixture of myo-inositol and d-chiro-inositol (80:1) in drinking water. The mice were characterised for heart morphology, function, electrical activity, arrhythmogenic susceptibility, and multiorgan histopathology (heart, liver and kidney). Cardiomyocyte size, protein expression of key signalling pathways related to hypertrophy, and transcription levels of ion channel subunits and hypertrophy markers were evaluated in the ventricle tissue. The study found that INO supplementation reduced the Li-induced cardiac adverse effects, including systolic impairment and increased susceptibility to arrhythmias. The positive effect on arrhythmias might be attributed to the restored expression levels of the potassium channel subunit Kv 1.5. Additionally, INO improved cardiomyocyte hypertrophy, possibly by inhibiting the Li-induced activation of the ERK1/2 signalling pathway and by restoring the normal expression level of BNP, and alleviated injury in the liver and kidney. The effect was preventive if INO supplementation was taken concurrently with Li and therapeutic if INO was administered after Li-induced cardiac impairments were established. These results provide new insights into the cardioprotective effect of INO and suggest a potential treatment approach for Li-induced cardiac disease.

11-Hydroxyeicosatetraenoics induces cellular hypertrophy in an enantioselective manner.

R/S enantiomers of 11-hydroxyeicosatertraenoic acid (11-HETE) are formed from arachidonic acid by enzymatic and non-enzymatic pathways. 11-HETE is predominately formed by the cytochrome P450 1B1 (CYP1B1). The role of CYP1B1 in the development of cardiovascular diseases is well established. This study aimed to assess the cellular hypertrophic effect of 11-HETE enantiomers in human RL-14 cardiomyocyte cell line and to examine their association with CYP1B1 levels. Human fetal ventricular cardiomyocyte, RL-14 cells, were treated with 20µM (R) or (S) 11-HETE for 24h. Thereafter, cellular hypertrophic markers and cell size were then determined using real-time polymerase chain reaction (RT-PCR) and phase-contrast imaging, respectively. The mRNA and protein levels of selected CYPs were determined using RT-PCR and Western blot, respectively. In addition, we examined the effect of (R) and (S) 11-HETE on CYP1B1 catalytic activity using human recombinant CYP1B1 and human liver microsomes. Both (R) and (S) 11-HETE induced cellular hypertrophic markers and cell surface area in RL-14 cells. Both enantiomers significantly upregulated CYP1B1, CYP1A1, CYP4F2, and CYP4A11 at the mRNA and protein levels, however, the effect of the S-enantiomer was more pronounced. Furthermore, 11(S)-HETE increased the mRNA and protein levels of CYP2J and CYP4F2, whereas 11(R)-HETE increased only CYP4F2. Only 11(S)-HETE significantly increased the catalytic activity of CYP1B1 in recombinant human CYP1B1, suggesting allosteric activation in an enantioselective manner. Our study provides the first evidence that 11-HETE can induce cellular hypertrophy in RL-14 cells via the increase in CYP1B1 mRNA, protein, and activity levels.

Baicalin ameliorates angiotensin II-induced cardiac hypertrophy and mitogen-activated protein kinase signaling pathway activation: A target-based network pharmacology approach

Baicalin, a flavonoid glycoside from Scutellaria baicalensis Georgi., exerts anti-hypertensive effects. The present study aimed to assess the cardioprotective role of baicalin and explore its potential mechanisms. Network pharmacology analysis pointed out a total of 477 potential targets of baicalin were obtained from the PharmMapper and SwissTargetPrediction databases, while 11,280 targets were identified associating with hypertensive heart disease from GeneCards database. Based on the above 382 common targets, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed enrichment in the regulation of cardiac hypertrophy, cardiac contraction, cardiac relaxation, as well as the mitogen-activated protein kinase (MAPK) and other signaling pathways. Moreover, baicalin treatment exhibited the amelioration of increased cardiac index and pathological alterations in angiotensin II (Ang II)-infused C57BL/6 mice. Furthermore, baicalin treatment demonstrated a reduction in cell surface area and a down-regulation of hypertrophy markers (including atrial natriuretic peptide and brain natriuretic peptide) in vivo and in vitro. In addition, baicalin treatment led to a decrease in the expression of phosphorylated c-Jun N-terminal kinase (p-JNK)/JNK, phosphorylated p38 (p-p38)/p38, and phosphorylated extracellular signal-regulated kinase (p-ERK)/ERK in the cardiac tissues of Ang II-infused mice and Ang II-stimulated H9c2 cells. These findings highlight the cardioprotective effects of baicalin, as it alleviates hypertensive cardiac injury, cardiac hypertrophy, and the activation of the MAPK pathway.

Abstract Tu036: Adipose tissue plasticity in response to early pathological stress on the heart and mediation by adipose thermogenic activation

Background: Cardiovascular diseases (CVD) are the leading cause of death globally, accounting for approximately 17.9 million mortalities per year. Previous studies have shown that there is an early response of white and brown adipose tissue (WAT and BAT, respectively) to pathological stress on the heart prior to cardiac dysfunction. Interestingly, human subjects with detectable BAT activity (a thermogenic tissue) exhibit a reduced risk of Congestive Heart Failure, but the mechanism for this is unclear. We hypothesized that increasing the thermogenic acitivity of adipose tissue would be beneficial during the initial cardiac hypertrophic signaling prior to the development of compensatory hypertrophy. Methods: We studied both WAT and BAT in male and female C57BL/6J mice subjected to cardiac pressure overload via transaortic constriction (TAC). 24 hours post-surgery, mice were subjected to room temperature (RT) 22° C or mild cold 16°C to stimulate BAT activation for 48 hours after which tissues were collected. The study groups included: SHAM RT, TAC RT, SHAM COLD, TAC COLD. We used uncoupling protein 1 knockout (UCP1-KO) mice, with impaired thermogenic activity as a negative control. Results: At 72 hours post tac surgery, expression of thermogenic and metabolic genes remained unchanged in BAT and WAT of both sexes. However, mild cold exposure resulted in an increase in UCP1 expression in BAT of male, but not female mice while other metabolic and thermogenic gene markers’ expression was increased in a sex-specific manner. Adaptations to scWAT were more moderate than BAT, with an increase in Ucp1 after cold exposure in both sexes. Moreover, 48 hours of cold exposure attenuated expression of gene markers for hypertrophic signaling in the heart during TAC. Importantly, these adaptations were absent in UCP1-KO mice, signifying that intact thermogenic activity in adipose tissue was required for the attenuated expression of hypertrophic markers in the heart. Interestingly, cardiac fibrosis markers were downregulated with TAC-Cold in male mice only, suggesting a stronger response compared to female mice. Conclusions: Our findings demonstrate that pathological stress on the heart during TAC does not impact adipose tisse thermogenesis. Additionally, activating thermogenic gene expression of adipose tissue via cold exposure mediates the early induction of hypertrophic signaling in the heart within 72 hours of TAC. Notably, adipose tissue plasticity is sex-specific.

Abstract We144: Fto Deficiency Causes Cardiac Dysfunction by Altering Expression of Serca2a mRNA

Introduction and Research Question: The impact of post-transcriptional regulation of gene expression, including N6-methyladenosine (m6A) messenger RNA methylation, on cardiac function has not yet been fully understood. Our study found that the absence of the m6A eraser, Fat mass and obesity-associated protein (Fto), in cardiomyocytes of adult mice led to cardiac dysfunction and cardiac hypertrophy. Methods and Results: To evaluate Fto physiological functions, we generated a tamoxifen-inducible cardiac-specific Fto knockout mouse model (Fto cKO). This resulted in a substantial reduction of Fto at both mRNA and protein levels in the whole heart, leading to an almost complete absence of Fto within cardiomyocytes. Echocardiography analyses showed that Fto cKO mice exhibit impaired cardiac functions, indicated by a 30% reduction in ejection fraction and 40% decrease in fractional shortening after one month of deletion of cardiac Fto ( p&lt;0.01 ). We found a significant increase in heart weight to body weight ratios in Fto cKO animals ( p&lt;0.05 ). This result corresponded with an increased expression of hypertrophic markers including Nppb and Myh7 mRNA in the absence of Fto ( p&lt;0.01 ). We noted an increase in the length of Fto cKO cardiomyocytes ( p&lt;0.05 ) in isolated cardiomyocytes, a characteristic feature of eccentric pathologic hypertrophy. Electron microscopy analysis of intact hearts showed ultrastructure abnormalities in cardiomyocytes from Fto cKO mice including Z-line density loss and disarray in cristae alignment of mitochondria. Moreover, cardiomyocytes from Fto cKO mice demonstrated defects in sarcomeric shortening including a prolongation of time to 90% peak, time to 90% rest, and decay time constant of relaxation for sarcomere shortening ( p&lt;0.001 ), compared to control mice. Mechanistically, we found down-regulation of Serca2a and Ryr2 mRNA in cardiomyocytes lacking Fto. We further demonstrated that Fto binds Serca2a mRNA and controls its cytoplasmic-nuclear shuttling. Fto deficiency led to accumulation of Serca2a mRNA in the nucleus. Conclusion: These findings suggest that Fto plays a pivotal role as a crucial regulator for cardiac function. Consequently, our results unveil a significant and novel mechanism through which Fto-dependent regulation contributes to the preservation of cardiac homeostasis.

Efficiently directing differentiation and homing of mesenchymal stem cells to boost cartilage repair in osteoarthritis via a nanoparticle and peptide dual-engineering strategy

Mesenchymal stem cells (MSCs) are expected to be useful therapeutics in osteoarthritis (OA), the most common joint disorder characterized by cartilage degradation. However, evidence is limited with regard to cartilage repair in clinical trials because of the uncontrolled differentiation and weak cartilage-targeting ability of MSCs after injection. To overcome these drawbacks, here we synthesized CuO@MSN nanoparticles (NPs) to deliver Sox9 plasmid DNA (favoring chondrogenesis) and recombinant protein Bmp7 (inhibiting hypertrophy). After taking up CuO@MSN/Sox9/Bmp7 (CSB NPs), the expressions of chondrogenic markers were enhanced while hypertrophic markers were decreased in response to these CSB-engineered MSCs. Moreover, a cartilage-targeted peptide (designated as peptide W) was conjugated onto the surface of MSCs via a click chemistry reaction, thereby prolonging the residence time of MSCs in both the knee joint cavity of mice and human-derived cartilage. In a surgery-induced OA mouse model, the NP and peptide dual-modified W-CSB-MSCs showed an enhancing therapeutic effect on cartilage repair in knee joints compared with other engineered MSCs after intra-articular injection. Most importantly, W-CSB-MSCs accelerated cartilage regeneration in damaged cartilage explants derived from OA patients. Thus, this new peptide and NPs dual engineering strategy shows potential for clinical applications to boost cartilage repair in OA using MSC therapy.

Plasticity Comparison of Two Stem Cell Sources with Different Hox Gene Expression Profiles in Response to Cobalt Chloride Treatment during Chondrogenic Differentiation.

The limited self-repair capacity of articular cartilage is a challenge for healing injuries. While mesenchymal stem/stromal cells (MSCs) are a promising approach for tissue regeneration, the criteria for selecting a suitable cell source remain undefined. To propose a molecular criterion, dental pulp stem cells (DPSCs) with a Hox-negative expression pattern and bone marrow mesenchymal stromal cells (BMSCs), which actively express Hox genes, were differentiated towards chondrocytes in 3D pellets, employing a two-step protocol. The MSCs' response to preconditioning by cobalt chloride (CoCl2), a hypoxia-mimicking agent, was explored in an assessment of the chondrogenic differentiation's efficiency using morphological, histochemical, immunohistochemical, and biochemical experiments. The preconditioned DPSC pellets exhibited significantly elevated levels of collagen II and glycosaminoglycans (GAGs) and reduced levels of the hypertrophic marker collagen X. No significant effect on GAGs production was observed in the preconditioned BMSC pellets, but collagen II and collagen X levels were elevated. While preconditioning did not modify the ALP specific activity in either cell type, it was notably lower in the DPSCs differentiated pellets compared to their BMSCs counterparts. These results could be interpreted as demonstrating the higher plasticity of DPSCs compared to BMSCs, suggesting the contribution of their unique molecular characteristics, including their negative Hox expression pattern, to promote a chondrogenic differentiation potential. Consequently, DPSCs could be considered compelling candidates for future cartilage cell therapy.

Spatiotemporal analysis of multi-scale cell structure in spheroid culture reveals hypertrophic chondrocyte differentiation

3D cell culture has emerged as a promising approach to replicate the complex behaviors of cells within living organisms. This study aims to analyze spatiotemporal behavior of the morphological characteristics of cell structure at multiscale in 3D scaffold-free spheroids using chondrogenic progenitor ATDC5 cells. Over a 14-day culture period, it exhibited cell hypertrophy in the spheroids regarding cellular and nuclear size as well as changes in morphology. Moreover, biological analysis indicated a signification up-regulation of normal chondrocyte as well as hypertrophic chondrocyte markers, suggesting early hypertrophic chondrocyte differentiation. Cell nuclei underwent changes in volume, sphericity, and distribution in spheroid over time, indicating alterations in chromatin organization. The ratio of chromatin condensation volume to cell nuclear volume decreased as the cell nuclei enlarged, potentially signifying changes in chromatin state during hypertrophic chondrocyte differentiation. Our image analysis techniques in this present study enabled detailed morphological measurement of cell structure at multi-scale, which can be applied to various 3D culture models for in-depth investigation.

Isoproterenol induced cardiac hypertrophy: A comparison of three doses and two delivery methods in C57BL/6J mice.

Heart Failure (HF) continues to be a complex public health issue with increasing world population prevalence. Although overall mortality has decreased for HF and hypertrophic cardiomyopathy (HCM), a precursor for HF, their prevalence continues to increase annually. Because the etiology of HF and HCM is heterogeneous, it has been difficult to identify novel therapies to combat these diseases. Isoproterenol (ISP), a non-selective β-adrenoreceptor agonist, is commonly used to induce cardiotoxicity and cause acute and chronic HCM and HF in mice. However, the variability in dose and duration of ISP treatment used in studies has made it difficult to determine the optimal combination of ISP dose and delivery method to develop a reliable ISP-induced mouse model for disease. Here we examined cardiac effects induced by ISP via subcutaneous (SQ) and SQ-minipump (SMP) infusions across 3 doses (2, 4, and 10mg/kg/day) over 2 weeks to determine whether SQ and SMP ISP delivery induced comparable disease severity in C57BL/6J mice. To assess disease, we measured body and heart weight, surface electrocardiogram (ECG), and echocardiography recordings. We found all 3 ISP doses comparably increase heart weight, but these increases are more pronounced when ISP was administered via SMP. We also found that the combination of ISP treatment and delivery method induces contrasting heart rate, RR interval, and R and S amplitudes that may place SMP treated mice at higher risk for sustained disease burden. Mice treated via SMP also had increased heart wall thickness and LV Mass, but mice treated via SQ showed greater increase in gene markers for hypertrophy and fibrosis. Overall, these data suggest that at 2 weeks, mice treated with 2, 4, or 10mg/kg/day ISP via SQ and SMP routes cause similar pathological heart phenotypes but highlight the importance of drug delivery method to induce differing disease pathways.

Exercise Reduces Glucose Intolerance, Cardiac Inflammation and Adipose Tissue Dysfunction in Psammomys obesus Exposed to Short Photoperiod and High Energy Diet.

Circadian disruption causes glucose intolerance, cardiac fibrosis, and adipocyte dysfunction in sand rats (Psammomys obesus). Exercise intervention can improve glucose metabolism, insulin sensitivity, adipose tissue function and protect against inflammation. We investigated the influence of exercise on male P. obesus exposed to a short photoperiod (5 h light:19 h dark) and high-energy diet. Exercise reduced glucose intolerance. Exercise reduced cardiac expression of inflammatory marker Ccl2 and Bax:Bcl2 apoptosis ratio. Exercise increased heart:body weight ratio and hypertrophy marker Myh7:Myh6, yet reduced Gata4 expression. No phenotypic changes were observed in perivascular fibrosis and myocyte area. Exercise reduced visceral adipose expression of inflammatory transcription factor Rela, adipogenesis marker Ppard and browning marker Ppargc1a, but visceral adipocyte size was unaffected. Conversely, exercise reduced subcutaneous adipocyte size but did not affect any molecular mediators. Exercise increased ZT7 Bmal1 and Per2 in the suprachiasmatic nucleus and subcutaneous Per2. Our study provides new molecular insights and histological assessments on the effect of exercise on cardiac inflammation, adipose tissue dysfunction and circadian gene expression in P. obesus exposed to short photoperiod and high-energy diet. These findings have implications for the protective benefits of exercise for shift workers in order to reduce the risk of diabetes and cardiovascular disease.

Cardiac programming in the placentally restricted sheep fetus in early gestation.

Fetal growth restriction (FGR) occurs in 8% of human pregnancies, and the growth restricted newborn is at a greater risk of developing heart disease in later adult life. In sheep, experimental restriction of placental growth (PR) from conception results in FGR, a decrease in cardiomyocyte endowment and an upregulation of pathological hypertrophic signalling in the fetal heart in late gestation. However, there is no change in the expression of markers of cellular proliferation nor in the level of cardiomyocyte apoptosis in the heart of the PR fetus in late gestation. This suggests that FGR arises early in gestation and programs a decrease in cardiomyocyte endowment in early, rather than late, gestation. Here, control and PR fetal sheep were humanely killed at 55 days' gestation (term, 150days). Fetal body and heart weight were lower in PR compared with control fetuses and there was evidence of sparing of fetal brain growth. While there was no change in the proportion of cardiomyocytes that were proliferating in the early gestation PR heart, there was an increase in measures of apoptosis, and markers of autophagy and pathological hypertrophy in the PR fetal heart. These changes in early gestation highlight that FGR is associated with evidence of early cell death and compensatory hypertrophic responses of cardiomyocytes in the fetal heart. The data suggest that early placental restriction results in a decrease in the pool of proliferative cardiomyocytes in early gestation, which would limit cardiomyocyte endowment in the heart of the PR fetus in late gestation. KEY POINTS: Placental restriction leading to fetal growth restriction (FGR) and chronic fetal hypoxaemia in sheep results in a decrease in cardiomyocyte endowment in late gestation. FGR did not change cardiomyocyte proliferation during early gestation but did result in increased apoptosis and markers of autophagy in the fetal heart, which may result in the decreased endowment of cardiomyocytes observed in late gestation. FGR in early gestation also results in increased hypoxia inducible factor signalling in the fetal heart, which in turn may result in the altered expression of epigenetic regulators, increased expression of insulin-like growth factor 2 and cardiomyocyte hypertrophy during late gestation and after birth.

Interleukin-5 alleviates cardiac remodelling via the STAT3 pathway in angiotensin II-infused mice.

Interleukin-5 (IL-5) has been reported to be involved in cardiovascular diseases, such as atherosclerosis and cardiac injury. This study aimed to investigate the effects of IL-5 on cardiac remodelling. Mice were infused with angiotensin II (Ang II), and the expression and source of cardiac IL-5 were analysed. The results showed that cardiac IL-5 expression was time- and dose-dependently decreased after Ang II infusion, and was mainly derived from cardiac macrophages. Additionally, IL-5-knockout (IL-5-/-) mice were used to observe the effects of IL-5 knockout on Ang II-induced cardiac remodelling. We found knockout of IL-5 significantly increased the expression of cardiac hypertrophy markers, elevated myocardial cell cross-sectional areas and worsened cardiac dysfunction in Ang II-infused mice. IL-5 deletion also promoted M2 macrophage differentiation and exacerbated cardiac fibrosis. Furthermore, the effects of IL-5 deletion on cardiac remodelling was detected after the STAT3 pathway was inhibited by S31-201. The effects of IL-5 on cardiac remodelling and M2 macrophage differentiation were reversed by S31-201. Finally, the effects of IL-5 on macrophage differentiation and macrophage-related cardiac hypertrophy and fibrosis were analysed invitro. IL-5 knockout significantly increased the Ang II-induced mRNA expression of cardiac hypertrophy markers in myocardial cells that were co-cultured with macrophages, and this effect was reversed by S31-201. Similar trends in the mRNA levels of fibrosis markers were observed when cardiac fibroblasts and macrophages were co-cultured. In conclusions, IL-5 deficiency promote the differentiation of M2 macrophages by activating the STAT3 pathway, thereby exacerbating cardiac remodelling in Ang II-infused mice. IL-5 may be a potential target for the clinical prevention of cardiac remodelling.

Fenofibrate reduces cardiac remodeling by mitochondrial dynamics preservation in a renovascular model of cardiac hypertrophy

Fenofibrate, a PPAR-α agonist clinically used to lower serum lipid levels, reduces cardiac remodeling and improves cardiac function. However, its mechanism of action is not completely elucidated. In this study we examined the effect of fenofibrate on mitochondria in a rat model of renovascular hypertension, focusing on mediators controlling mitochondrial dynamics and autophagy.Rats with two-kidney one-clip (2K1C) hypertension were treated with fenofibrate 150 mg/kg/day (2K1C-FFB) or vehicle (2K1C-VEH) for 8 weeks. Systolic blood pressure and cardiac functional were in-vivo assessed, while cardiomyocyte size and protein expression of mediators of cardiac hypertrophy and mitochondrial dynamics were ex-vivo examined by histological and Western blot analyses.Fenofibrate treatment counteracted the development of hypertension and the increase of left ventricular mass, relative wall thickness and cross-sectional area of cardiomyocytes. Furthermore, fenofibrate re-balanced the expression Mfn2, Drp1 and Parkin, regulators of fusion, fission, mitophagy respectively. Regarding autophagy, the LC3-II/LC3-I ratio was increased in 2K1C-VEH and 2K1C-FFB, whereas the autophagy was increased only in 2K1C-FFB.In cultured H9C2 cardiomyoblasts, fenofibrate reversed the Ang II-induced mRNA up-regulation of hypertrophy markers Nppa and Myh7, accumulation of reactive oxygen species and depolarization of the mitochondrial membrane exerting protection mediated by up-regulation of the Uncoupling protein 2.Our results indicate that fenofibrate acts directly on cardiomyocytes and counteracts the pressure overload-induced cardiac maladaptive remodeling. This study reveals a so far hidden mechanism involving mitochondrial dynamics in the beneficial effects of fenofibrate, support its repurposing for the treatment of cardiac hypertrophy and provide new potential targets for its pharmacological function.