Constriction Model Research Articles

Empagliflozin improves pressure-overload-induced cardiac hypertrophy by inhibiting the canonical Wnt/β-catenin signaling pathway.

Empagliflozin (EMPA) is an SGLT-2 inhibitor that can control hyperglycemia. Clinical trials have indicated its cardio-protective effects against cardiac remodeling in diabetes or non-diabetes patients. However, the underlying molecular mechanisms of EMPA's cardio-protective effects remain elusive. We evaluated whether the EMPA attenuated the pressure-overload-induced cardiac hypertrophy by inhibiting the Wnt/β-catenin pathway. Furthermore, the effects of the EMPA on a mouse model of transverse aortic constriction (TAC) induced cardiac hypertrophy was also evaluated. Mice were administrated with 0.5% CMC-Na as a vehicle or EMPA (10mg/kg/day, daily, throughout the study) by intragastric gavage. The in vivo echocardiography and histologic morphological analyses revealed that EMPA attenuated TAC-induced cardiac hypertrophy. Moreover, it also ameliorated TAC-induced cardiac fibrosis and decreased the cell size of the cardiomyocytes in isolated adult cardiomyocytes. Molecular mechanism analysis revealed that the EMPA reduced the TAC-induced enhanced expression of the Wnt/β-catenin pathway in vivo. For in vitro assessments, isolated neonatal rat cardiomyocytes (NRCMs) were treated with Angiotensin II (AngII) and EMPA; the results showed that in the absence of EMPA, the expression of the Wnt/β-catenin pathway was enhanced. In the trans-genetic heterozygous β-catenin deletion mice, EMPA attenuated TAC-induced cardiac remodeling by reducing the Wnt/β-catenin pathway. In addition, molecular docking analysis indicated that EMPA interacts with FZD4 to inhibit the TAC and AngII induced Wnt/β-catenin pathway in cardiomyocytes. Our study illustrated that EMPA might directly interact with FZD4 to inhibit the TAC and AngII-induced activation of the Wnt/β-catenin pathway to attenuate the adverse cardiac remodeling.

Stress memory of heart failure in hematopoietic niche promotes recurrence via adipocytic skewing of mesenchymal stromal cells

Abstract Background Heart failure (HF) is marked by recurrent acute decompensations, which poses significant treatment challenges in advanced stages. Our preceding work demonstrated that hematopoietic stem cells (HSCs) from HF-experienced mice induce cardiac fibrosis and dysfunction when transplanted, as a result of epigenetic alterations favoring myeloid hematopoiesis and impeding the differentiation of monocytes into cardiac mature macrophages. These findings hint at epigenetic modifications in HSCs as potential drivers of HF recurrence, suggesting their manipulation as a novel therapeutic strategy. However, the exact mechanisms by which HF-associated stress leads to these epigenetic changes remain unclear. Given the crucial role of bone marrow mesenchymal stromal cells (MSCs) in maintaining HSC stemness, this study explores the impact of cardiac stress on MSC function and its subsequent effect on HSCs. Purpose This study aims to elucidate the mechanisms behind the phenotypic changes in HSCs and to identify novel therapeutic targets to mitigate HF recurrence by investigating the role of MSCs in the hematopoietic niche under cardiac stress. Methods & Results Initially, we examined MSC phenotypic changes during HF using bulk and single-cell RNA sequencing. Results from transverse aortic constriction (TAC) model mice revealed a shift towards adipocyte differentiation under cardiac stress. Histological analyses confirmed an increase in adipocytes in TAC mice compared to controls, suggesting a stress-induced predisposition of MSCs towards adipocytic lineage commitment. This trend was further supported by ex vivo models using MSCs isolated from TAC mice. Notably, the proportion of adipocyte lineage-specific MSCs correlated with cardiac dysfunction severity. Subsequently, we assessed the impact of HF-conditioned MSCs on HF development by transplanting healthy HSCs with MSCs from control or TAC mice. Mice receiving HF-conditioned MSCs developed HF, evidenced by reduced ejection fraction and cardiac fibrosis. In these mice, a notable increase in HSC proliferation and a relative increase of myeloid cells within the peripheral blood were observed, along with an increase in proinflammatory cardiac macrophages. These findings suggest HF induces a "stress memory" in bone marrow MSCs. To test the potential of inhibiting adipocyte differentiation of MSCs in erasing this stress memory, we administered MSC phenotype-modulating agents to TAC mice, resulting in improved cardiac function and the disappearance of adipocytes from the bone marrow. Conclusions This study sheds light on how cardiac stress affects the bone marrow niche, leading to adipocytic skewing of MSCs and subsequent alterations in HSCs, thereby exacerbating cardiac dysfunction. The potential of targeting bone marrow niche components in HF treatment is highlighted.

Remodeling of adult rat heart subjected to pressure overload from the neonatal period is dependent on the sex

Abstract Background Congenital heart diseases (CHD) represents the most common birth defect. Despite progress in their treatment improving acute survival, there is a paucity of data concerning the long-term consequences of CHD in adults. Purpose Here, we investigate the remodeling in adult rat hearts subjected to pressure overload from the early postnatal period. Methods We used the neonatal abdominal aortic constriction (AAC) model to analyze morphological, functional (by echocardiography), and electrophysiological long-term outcomes. Given the known differences in cardiac pathologies between males (M) and females (F), we focused on the role of sex in cardiac remodeling. Results Our data showed that both sexes exhibited a similar left ventricular weight/body weight ratio at the age of 12 weeks, indicating comparable left ventricle (LV) enlargement as a response to AAC (increase by 103 ± 9 % in M AAC and 99 ± 10 % in F AAC vs. sham-operated animals). However, the right ventricular weight/body weight and lung/ body weight ratios, indicative of LV failing, differed significantly between sexes with better values in F AAC. The favorable cardiac remodeling in F AAC was corroborated by significantly smaller LV systolic and diastolic diameters, along with a lower amount of myocardial fibrosis. Using optical mapping, we revealed preserved longitudinal and transversal conduction velocities (CVL; CVT) in females (CVL 104 ± 8 vs. 109 ± 8 cm/s and CVT 66 ± 7 vs. 59 ± 6 cm/s in F AAC and F Sham, respectively). However, compared to M Sham, the conduction velocities in M AAC showed a significant decrease (CVL 80 ± 3 vs. 92 ± 3 cm/s and CVT 35 ± 2 vs. 54 ± 3 cm/s). Similarly, the amount of connexion 43 (Cx43) and its phosphorylated state (Cx43Ser368) was preserved in F AAC while exhibiting a decrease in M AAC compared to the sham-operated controls. Thus, electrophysiological findings implicate that while the adult M AAC underwent pro-arrhythmogenic remodeling due to the elevated workload, the adult F AAC preserved physiological conduction properties. Conclusion Our data showed different consequences of the increased pressure load exposed from early after birth to the adult M and F heart. These findings highlighted the involvement of both sexes in cardiac studies.

Interleukin-22 inhibits right ventricular remodelling by a unique mechanism in a pulmonary artery constriction model

Abstract Background Fibrosis and remodeling of right ventricle (RV) are associated with prognosis in patients with RV failure. Interleukin-22 (IL-22) is a member of the IL-10 cytokine family, play roles in tissue protection and wound repair. We have previously shown that IL-22 plays an important role in cardiac remodeling after acute myocardial infarction; however, the role of IL-22 in RV fibrosis and remodeling remains elusive. Purpose We investigated the role of IL-22 in the pathogenesis of RV remodeling during pressure overload. Methods Pulmonary artery banding (PAB) is performed by placing a 6-0 suture around the pulmonary artery over a 24 G needle in wild type mice (C57BL/6J) and IL-22 knockout mice (IL-22 KO). Only mice with moderate pulmonary artery stenosis (peak pressure gradient across the pulmonary band: 25–40 mmHg at 1 week after surgery by echo Doppler) were included in the study protocol. Four weeks after PAB, RV function was measured by echocardiography and real-time PCR analysis was performed to measure Col1a1, Col3a1, BNP, and transcriptome analysis was performed. Survival confirmation of mice with moderate pulmonary artery stenosis was also performed up to 56 days. Results IL-22 KO mice had significantly higher 56-day mortality rate compared with WT mice after PAC (p<0.01). Four weeks after PAB, IL-22 KO mice showed markedly increased RV weight (IL-22 KO mice vs. wild-type mice; RV/LV+IVS: 0.48±0.05 vs 0.40±0.02, P=0.002). IL-22 KO mice exhibited significant RV enlargement and RV dysfunction 4 weeks after PAB. (IL-22 KO mice vs wild type mice; RVEDV: 10±2.3mm2 vs 12.9±3.1mm2, P=0.005, TAPSE: 10.8±1.8mm vs 9.5±1.7mm, P=0.04, FAC: 35.2±7.8% vs 23±6.0%, P<0.001). The expressions of Col1a1 and Col3a1 were no difference between in IL22-KO mice and Wild mice. However, BNP, a cardioprotective marker, tended to be lower in IL-22KO mice. The transcriptome analysis also showed that the group of fibrosis-related genes that are elevated in PAC in WT mice were less elevated in IL-22 KO mice. Conclusion These results suggest that IL-22 is involved in RV remodelling during RV pressure loading without a general mechanism.

Cardamonin intervenes in myocardial hypertrophy progression by regulating Usp18

BackgroundMyocardial hypertrophy is a chronic cardiac condition that often occurs from long-term pressure or volumetric load on the heart. Propranolol hydrochloride has been employed in research on hypertension, pheochromocytoma, myocardial infarction, arrhythmias, angina pectoris, and hypertrophic cardiomyopathy. Current treatments for this condition have side effects, such as arrhythmias and myocardial cell death, thus necessitating safer and more effective alternatives. Recently, natural products have gained attention in drug development because of their low toxicity and high efficacy. Cardamonin, a compound derived from Chinese herbal materials, has shown potential in inhibiting oxidative stress and inflammation, which is beneficial for cardiovascular health. Nevertheless, the impact on myocardial hypertrophy and cardiac remodeling is still uncertain MethodsApproach We employed a transverse aortic constriction (TAC)model to simulate the pathological conditions of myocardial hypertrophy. Mice were administered varying doses of CAR (10 and 40 mg kg-1/d), and cardiac function was assessed using techniques such as echocardiography, qPCR, Masson staining, DHE staining, immunofluorescence, and immunohistochemistry. Propranolol hydrochloride was the positive control for observing the anti-myocardial hypertrophic effects of CAR. ResultsCardamonin significantly reduced TAC-induced myocardial hypertrophy, fibrosis, inflammation, and oxidative stress. High CAR concentrations showed better anti-myocardial remodeling effects. The anti-hypertrophic effect of cardamonin was similar to that of propranolol hydrochloride. Further investigating the mechanism of action revealed that ubiquitin-specific peptidase (USP)18, a deubiquitnating enzyme that regulates various cellular signaling pathways, was a key downstream regulator affected by cardamonin. To confirm this, AAV9-cTNT-Usp18 and Usp18 myocardial-specific knockout mice were generated and treated with TAC. Usp18 downregulation was found to interfere with the protective effects of CAR against myocardial remodeling, whereas its overexpression enhanced these effects. ConclusionThis study used propranolol as a positive control and provided the first in-depth exploration of the concentration-dependent effects of cardamonin on myocardial hypertrophy and cardiac remodeling. CAR is a new candidate drug for cardiovascular disease treatment. This comparative study provides evidence for assessing the clinical application potential of new drugs and delves into its mechanisms of action, particularly the interaction with Usp18. Comprehending these mechanisms is beneficial for formulating more targeted future treatment approaches.

Abstract Tu099: GDF11 accelerates NF-kB-mediated inflammation prior to reduction in cardiac fibrosis in response to experimental pressure overload.

Background: Cardiac fibrosis is a common pathophysiology in a broad variety of heart diseases. GDF11, a member of the TGF-beta superfamily, can reduce cardiac hypertrophy and fibrosis in the pressure overload model of experimental Trans Aortic Constriction (TAC). However, the molecular mechanisms by which GDF11 can reduce cardiac fibrosis are incompletely described. Hypothesis: GDF11 is known to activate both NF-kB as well as SMAD2/3 signaling which are essential in cardiac fibrosis and hypertrophy processes. We hypothesized that exogenous GDF11 can change the dynamics of early inflammatory NF-kB target genes during the response to pressure overload. Methods: We used mice implanted with AngII-osmotic pumps to induce left ventricular fibrosis. The mice were harvested at different time points: 3, 7, 14, and 28 days post-pump implantation (ppi) to follow the evolution of cardiac fibrosis and cardiac hypertrophy, and to identify the role of GDF11 in modulating these processes. Results: GDF11 delivery (1mg/kg every other day) in AngII mice (AngII+GDF11) induced earlier expression of NF-kB target genes (IL-1beta, IL-6, TNF-alpha – p>0.05) compared to AngII+Veh control group at 3d ppi, revealing accelerated activation of NF-kB response pathways in AngII+GDF11 group. This is associated with faster recruitment of the M1 macrophage population observed by an increased expression of CD86 or iNOS at 3d ppi. We also observed decreased markers of fibroblast activation after GDF11 supplementation, with less collagen deposition (F-CHP) and fibrosis (Masson Trichrome) at 28 days. Conclusions: Our data suggest that exogenous GDF11 changes the dynamics of NF-kB inflammatory mechanisms while reducing later fibrosis. This new finding could suggest that the dynamics of the inflammatory response early after pressure overload is a critical factor in cardiac fibrosis.

Fibroblast Smad7 Induction Protects the Remodeling Pressure-Overloaded Heart.

Cardiac fibroblast activation contributes to adverse remodeling, fibrosis, and dysfunction in the pressure-overloaded heart. Although early fibroblast TGF-β (transforming growth factor-β)/Smad (small mother against decapentaplegic)-3 activation protects the pressure-overloaded heart by preserving the matrix, sustained TGF-β activation is deleterious, accentuating fibrosis and dysfunction. Thus, endogenous mechanisms that negatively regulate the TGF-β response in fibroblasts may be required to protect from progressive fibrosis and adverse remodeling. We hypothesized that Smad7, an inhibitory Smad that restrains TGF-β signaling, may be induced in the pressure-overloaded myocardium and may regulate fibrosis, remodeling, and dysfunction. The effects of myofibroblast-specific Smad7 loss were studied in a mouse model of transverse aortic constriction, using echocardiography, histological analysis, and molecular analysis. Proteomic studies in S7KO (Smad7 knockout) and overexpressing cells were used to identify fibroblast-derived mediators modulated by Smad7. In vitro experiments using cultured cardiac fibroblasts, fibroblasts populating collagen lattices, and isolated macrophages were used to dissect the molecular signals responsible for the effects of Smad7. Following pressure overload, Smad7 was upregulated in cardiac myofibroblasts. TGF-β and angiotensin II stimulated fibroblast Smad7 upregulation via Smad3, whereas GDF15 (growth differentiation factor 15) induced Smad7 through GFRAL (glial cell line-derived neurotrophic factor family receptor α-like). MFS7KO (myofibroblast-specific S7KO) mice had increased mortality, accentuated systolic dysfunction and dilative remodeling, and accelerated diastolic dysfunction in response to transverse aortic constriction. Increased dysfunction in MFS7KO hearts was associated with accentuated fibrosis and increased MMP (matrix metalloproteinase)-2 activity and collagen denaturation. Secretomic analysis showed that Smad7 loss accentuates secretion of structural collagens and matricellular proteins and markedly increases MMP2 secretion. In contrast, Smad7 overexpression reduced MMP2 levels. In fibroblasts populating collagen lattices, the effects of Smad7 on fibroblast-induced collagen denaturation and pad contraction were partly mediated via MMP2 downregulation. Surprisingly, MFS7KO mice also exhibited significant macrophage expansion caused by paracrine actions of Smad7 null fibroblasts that stimulate macrophage proliferation and fibrogenic activation. Macrophage activation involved the combined effects of the fibroblast-derived matricellular proteins CD5L (CD5 antigen-like), SPARC (secreted protein acidic and rich in cysteine), CTGF (connective tissue growth factor), ECM1 (extracellular matrix protein 1), and TGFBI (TGFB induced). The antifibrotic effects of Smad7 in the pressure-overloaded heart protect from dysfunction and involve not only reduction in collagen deposition but also suppression of MMP2-mediated matrix denaturation and paracrine effects that suppress macrophage activation through inhibition of matricellular proteins.

A novel degradable PEG superparamagnetic iron oxide capsule coupled with a polyphenolic nano-enzymatic conjugate (PSPM-NE), to treat ROS-driven cardiovascular-diseases, tested in atherosclerosis as a model disease, and hypothesizing autoimmunity as an atheroma's trigger.

Cardiovascular diseases account for a significant portion of the worldwide mortality rate. This aroused interest among the specialised scientific community, seeking for solutions based on non-clinical and clinical investigations, to shed light onto the physio-pathology of cardiovascular impairment. It is proven challenging managing chronic cardiovascular illnesses like atherosclerosis, arrhythmias, and diverse cardiomyopathies. In certain cases, there is no approved treatment. In other cases, the need for combining therapeutic components, when dealing with co-morbidities, may increase the risk of toxicity-driven cardiovascular impairment. In this case, because the risk of cardiac events correlates with the QT prolongation rates, the QT or QTc interval prolongation has become an important biomarker to access drug-related cardio-toxicity. Several approaches have been found in the current literature, aiming at improving physiological acceptance, i.e., to reduce toxicity. Nanotechnology has increasingly appeared as a promising ally to modulate active substances, preserving cardiovascular function and optimising drug effectiveness, i.e., acting as a cardio-protective mechanism, leveraging the effects of drug-driven cardio-toxicity. In this manuscript, the author combines plant active compounds and nanotechnological strategies, e.g., nano-encapsulation, nano-enzymes, magnetically driven nano-delivery systems, applied in regenerative medicine, and assesses their effects on the cardiovascular system, e.g., as cardio-protective factors, reducing cardio-toxicity. The aim is to propose a new strategy to tackle atherosclerosis initiation and progression, in a drug design that targets ROS-removal and reduces inflammation, using auto-immunity biomarkers to select key atheroma-related signalling cascades. To analyse physiological phenomena related to atherosclerosis initiation and progression, the author proposes both experimental observations and a new haemorheological computational model of arterial constriction. The results of such analysis are used as motivators in the design of the here presented strategy to tackle atheroma. This novel design is based on degradable polyethylene glycol (PEG) superparamagnetic iron oxide capsule coupled with a polyphenolic nano-enzymatic conjugate (PSPM-NE).

Overexpression of ATP5F1A in Cardiomyocytes Promotes Cardiac Reverse Remodeling.

The mechanism of cardiac reverse remodeling (CRR) mediated by the left ventricular assist device remains unclear. This study aims to identify the specific cell type responsible for CRR and develop the therapeutic target that promotes CRR. The nuclei were extracted from the left ventricular tissue of 4 normal controls, 4 CRR patients, and 4 no cardiac reverse remodeling patients and then subjected to single-nucleus RNA sequencing for identifying key cell types responsible for CRR. Gene overexpression in transverse aortic constriction and dilated cardiomyopathy heart failure mouse model (C57BL/6J background) and pathological staining were performed to validate the results of single-nucleus RNA sequencing. Ten cell types were identified among 126 156 nuclei. Cardiomyocytes in CRR patients expressed higher levels of ATP5F1A than the other 2 groups. The macrophages in CRR patients expressed more anti-inflammatory genes and functioned in angiogenesis. Endothelial cells that elevated in no cardiac reverse remodeling patients were involved in the inflammatory response. Echocardiography showed that overexpressing ATP5F1A through cardiomyocyte-specific adeno-associated virus 9 demonstrated an ability to improve heart function and morphology. Pathological staining showed that overexpressing ATP5F1A could reduce fibrosis and cardiomyocyte size in the heart failure mouse model. The present results of single-nucleus RNA sequencing and heart failure mouse model indicated that ATP5F1A could mediate CRR and supported the development of therapeutics for overexpressing ATP5F1A in promoting CRR.

Tipifarnib Reduces Extracellular Vesicles and Protects From Heart Failure.

Heart failure (HF) is one of the leading causes of mortality worldwide. Extracellular vesicles, including small extracellular vesicles or exosomes, and their molecular cargo are known to modulate cell-to-cell communication during multiple cardiac diseases. However, the role of systemic extracellular vesicle biogenesis inhibition in HF models is not well documented and remains unclear. We investigated the role of circulating exosomes during cardiac dysfunction and remodeling in a mouse transverse aortic constriction (TAC) model of HF. Importantly, we investigate the efficacy of tipifarnib, a recently identified exosome biogenesis inhibitor that targets the critical proteins (Rab27a [Ras associated binding protein 27a], nSMase2 [neutral sphingomyelinase 2], and Alix [ALG-2-interacting protein X]) involved in exosome biogenesis for this mouse model of HF. In this study, 10-week-old male mice underwent TAC surgery were randomly assigned to groups with and without tipifarnib treatment (10 mg/kg 3 times/wk) and monitored for 8 weeks, and a comprehensive assessment was conducted through performed echocardiographic, histological, and biochemical studies. TAC significantly elevated circulating plasma exosomes and markedly increased cardiac left ventricular dysfunction, cardiac hypertrophy, and fibrosis. Furthermore, injection of plasma exosomes from TAC mice induced left ventricular dysfunction and cardiomyocyte hypertrophy in uninjured mice without TAC. On the contrary, treatment of tipifarnib in TAC mice reduced circulating exosomes to baseline and remarkably improved left ventricular functions, hypertrophy, and fibrosis. Tipifarnib treatment also drastically altered the miRNA profile of circulating post-TAC exosomes, including miR 331-5p, which was highly downregulated both in TAC circulating exosomes and in TAC cardiac tissue. Mechanistically, miR 331-5p is crucial for inhibiting the fibroblast-to-myofibroblast transition by targeting HOXC8, a critical regulator of fibrosis. Tipifarnib treatment in TAC mice upregulated the expression of miR 331-5p that acts as a potent repressor for one of the fibrotic mechanisms mediated by HOXC8. Our study underscores the pathological role of exosomes in HF and fibrosis in response to pressure overload. Tipifarnib-mediated inhibition of exosome biogenesis and cargo sorting may serve as a viable strategy to prevent progressive cardiac remodeling in HF.

Cardiomyocyte-specific RXFP1 overexpression protects against pressure overload-induced cardiac dysfunction independently of relaxin

Heart failure (HF) prevalence is rising due to reduced early mortality and demographic change. Relaxin (RLN) mediates protective effects in the cardiovascular system through Relaxin-receptor 1 (RXFP1). Cardiac overexpression of RXFP1 with additional RLN supplementation attenuated HF in the pressure-overload transverse aortic constriction (TAC) model. Here, we hypothesized that robust transgenic RXFP1 overexpression in cardiomyocytes (CM) protects from TAC-induced HF even in the absence of RLN.Hence, transgenic mice with a CM-specific overexpression of human RXFP1 (hRXFP1tg) were generated. Receptor functionality was demonstrated by in vivo hemodynamics, where the administration of RLN induced positive inotropy strictly in hRXFP1tg. An increase in phospholamban-phosphorylation at serine 16 was identified as a molecular correlate. hRXFP1tg were protected from TAC without additional RLN administration, presenting not only less decline in systolic left ventricular (LV) function but also abrogated LV dilation and pulmonary congestion compared to WT mice. Molecularly, transgenic hearts exhibited not only a significantly attenuated fetal and fibrotic gene activation but also demonstrated less fibrotic tissue and CM hypertrophy in histological sections. These protective effects were evident in both sexes. Similar cardioprotective effects of hRXFP1tg were detectable in a RLN-knockout model, suggesting an alternative mechanism of receptor activation through intrinsic activity, alternative endogenous ligands or crosstalk with other receptors.In summary, CM-specific RXFP1 overexpression provides protection against TAC even in the absence of endogenous RLN. This suggests RXFP1 overexpression as a potential therapeutic approach for HF, offering baseline protection with optional RLN supplementation for specific activation.

Neutrophils orchestrate early cardiac remodeling after cardiac pressure overload

Cardiac pressure overload is a chronic condition where the left ventricle undergoes pathological hypertrophy and fibrosis ultimately causing heart failure. Increased myocardial stretch in left ventricular pressure overload initiates activation of an inflammatory and fibrotic response within resident cells leading to infiltration of immune cells. Neutrophils and monocytes are among the first responders during cardiac injury. While the role of monocytes and macrophages in pressure overload has been somewhat elucidated by multiple groups, including our lab, the role of neutrophils in chronic cardiac injury such as pressure overload is still unclear. We hypothesized that, like acute ischemic injury, neutrophils infiltrate to the heart early in pressure overload and initiate an inflammatory cascade which worsens cardiac dysfunction after TAC and that depletion of neutrophils in the first week of TAC would improve cardiac function. Our published single cell RNAseq dataset of immune cells (CD45+) cells from sham and TAC heart at day (D) 7 shows a distinct clustering of neutrophils with S100a9 (34-fold) , S100a8 (31-fold) , Retnlg (9-fold) , Il1b (5-fold) , and Slpi (5-fold) as top 5 differentially expressed genes (DEGs). Geneset enrichment analysis of top 58 DEGs (≥1.5-folds), shows significant association with pathways such as innate immune system, neutrophil degranulation, and signaling by interleukins by Reactome 2022 pathway. Using a murine model of transaortic constriction (TAC) to induce left ventricular pressure overload, we evaluated cardiac neutrophil counts by flow cytometry over the first week of TAC at D 2, 4 and 7. We observed that neutrophils (CD45+Ly6G+CD11b+) numbers consistently increase until D4, with a 7-fold increase at D2 to a 17-fold increase at D4 before returning to sham levels by D7. Using antibody (Anti Gr-1, 4 ug/g) mediated depletion of neutrophils, we observed that neutrophil depletion showed a protective effect in females compared to isotype controls with decreased cardiac hypertrophy and improved ejection fraction; while in male mice no change was observed between isotype and antibody treated groups. In conclusion, our data show that neutrophils peak early in pressure overload and orchestrate early cardiac remodeling with a potential for a sexually dimorphic role. We acknowledge funding from National Institute of Health under the awards numbers HL155993 and HL160665. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Infraorbital nerve injury triggers sex-specific neuroimmune responses in the peripheral trigeminal pathway and common pain behaviours

Trigeminal neuropathic pain is emotionally distressing and disabling. It presents with allodynia, hyperalgesia and dysaesthesia. In preclinical models it has been assumed that cephalic nerve constriction injury shows identical molecular, cellular, and sex dependent neuroimmune changes as observed in extra-cephalic injury models. This study sought empirical evidence for such assumptions using the infraorbital nerve chronic constriction model (ION-CCI). We compared the behavioural consequences of nerve constriction with: (i) the temporal patterns of recruitment of macrophages and T-lymphocytes at the site of nerve injury and in the trigeminal ganglion; and (ii) the degree of demyelination and axonal reorganisation in the injured nerve. Our data demonstrated that simply testing for allodynia and hyperalgesia as is done in extra-cephalic neuropathic pain models does not provide access to the range of injury-specific nociceptive responses and behaviours reflective of the experience of trigeminal neuropathic pain. Similarly, trigeminal neuroimmune changes evoked by nerve injury are not the same as those identified in models of extra-cephalic neuropathy. Specifically, the timing, magnitude, and pattern of ION-CCI evoked macrophage and T-lymphocyte activity differs between the sexes.

Pharmacodynamics and Mechanism of Astragali Radix and Anemarrhenae Rhizoma in Treating Chronic Heart Failure by Inhibiting Complement Activation.

Astragali radix (AR) and anemarrhenae rhizoma (AAR) are used clinically in Chinese medicine for the treatment of chronic heart failure (CHF), but the exact therapeutic mechanism is unclear. In this study, a total of 60 male C57BL/6 mice were divided into 5 groups, namely sham, model, AR, AAR, and AR-AAR. In the sham group, the chest was opened without ligation. In the other groups, the chest was opened and the transverse aorta was ligated to construct the transverse aortic constriction model. After 8 weeks of feeding, mice were given medicines by gavage for 4 weeks. Left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were detected by echocardiography. Heart weight index (HWI) and wheat germ agglutinin staining were used to evaluate cardiac hypertrophy. Hematoxylin-eosin staining was used to observe the pathological morphology of myocardial tissue. Masson staining was used to evaluate myocardial fibrosis. The content of serum brain natriuretic peptide (BNP) was detected by enzyme-linked immunosorbent assay kit. The content of serum immunoglobulin G (IgG) was detected by immunoturbidimetry. The mechanism of AR-AAR in the treatment of CHF was explored by proteomics. Western blot was used to detect the protein expressions of complement component 1s (C1s), complement component 9 (C9), and terminal complement complex 5b-9 (C5b-9). The results show that AR-AAR inhibits the expression of complement proteins C1s, C9, and C5b-9 by inhibiting the production of IgG antibodies from B cell activation, which further inhibits the complement activation, attenuates myocardial fibrosis, reduces HWI and cardiomyocyte cross-sectional area, improves cardiomyocyte injury, reduces serum BNP release, elevates LVEF and LVFS, improves cardiac function, and exerts myocardial protection.

Polymeric liquids in mesoporous photonic structures: From precursor film spreading to imbibition dynamics at the nanoscale

Polymers are known to wet nanopores with high surface energy through an atomically thin precursor film followed by slower capillary filling. We present here light interference spectroscopy using a mesoporous membrane-based chip that allows us to observe the dynamics of these phenomena in situ down to the sub-nanometer scale at milli- to microsecond temporal resolution. The device consists of a mesoporous silicon film (average pore size 6 nm) with an integrated photonic crystal, which permits to simultaneously measure the phase shift of thin film interference and the resonance of the photonic crystal upon imbibition. For a styrene dimer, we find a flat fluid front without a precursor film, while the pentamer forms an expanding molecular thin film moving in front of the menisci of the capillary filling. These different behaviors are attributed to a significantly faster pore-surface diffusion compared to the imbibition dynamics for the pentamer and vice versa for the dimer. In addition, both oligomers exhibit anomalously slow imbibition dynamics, which could be explained by apparent viscosities of six and eleven times the bulk value, respectively. However, a more consistent description of the dynamics is achieved by a constriction model that emphasizes the increasing importance of local undulations in the pore radius with the molecular size and includes a sub-nanometer hydrodynamic dead, immobile zone at the pore wall but otherwise uses bulk fluid parameters. Overall, our study illustrates that interferometric, opto-fluidic experiments with mesoporous media allow for a remarkably detailed exploration of the nano-rheology of polymeric liquids.

Protective effects of METRNL overexpression against pathological cardiac remodeling

At present, meteorin-like protein (METRNL) has been proven to be widely expressed in the myocardium and participates in the pathogenic process of various cardiovascular diseases. However, the effects of METRNL on pathological cardiac hypertrophy is still unknown. In the present study, we used a mouse model of transverse aortic constriction (TAC) surgery to mimic pathological cardiac hypertrophy and gene delivery system to overexpress METRNL in vivo. The results showed that METRNL overexpression improved TAC-induced pathological cardiac hypertrophy in mice and neonatal cardiomyocytes. In addition, METRNL overexpression diminished TAC-induced cardiac oxidative damage, inflammation and cardiomyocyte apoptosis. Moreover, the cardioprotective effect of METRNL overexpression was directly related to the activation of AMP-activated protein kinase (AMPK) and sirtuin1 (SIRT1). In summary, our data identified that METRNL may be a promising therapeutic target to mitigate pathological cardiac hypertrophy in the future.

Advanced Magnetic Resonance Imaging to Define the Microvascular Injury Driven by Neuroinflammation in the Brain of a Mouse Model of Hypertension.

Hypertension is one of the main risk factors for dementia and cognitive impairment. We used the model of transverse aortic constriction to induce chronic pressure overload in mice. We characterized brain injury by advanced translational applications of magnetic resonance imaging. In parallel, we analyzed peripheral target organ damage induced by chronic pressure overload by ultrasonography. Microscopical characterization of brain vasculature was performed as well, together with the analysis of immune and inflammatory markers. We identified a specific structural, microstructural, and functional brain injury. In particular, we highlighted a regional enlargement of the hypothalamus, microstructural damage in the white matter of the fimbria, and a reduction of the cerebral blood flow. A parallel analysis performed by confocal microscopy revealed a correspondent tissue damage evidenced by a reduction of cerebral capillary density, paired with loss of pericyte coverage. We assessed cognitive impairment and cardiac damage induced by hypertension to perform correlation analyses with the brain injury severity. At the mechanistic level, we found that CD8+T cells, producing interferon-γ, infiltrated the brain of hypertensive mice. By neutralizing this proinflammatory cytokine, we obtained a rescue of the phenotype, demonstrating their crucial role in establishing the microvascular damage. Overall, we have used translational tools to comprehensively characterize brain injury in a mouse model of hypertension induced by chronic pressure overload. We have identified early cerebrovascular damage in hypertensive mice, sustained by CD8+IFN-γ+T lymphocytes, which fuel neuroinflammation to establish the injury of brain capillaries.

Cardiomyocyte-derived USP28 negatively regulates antioxidant response and promotes cardiac hypertrophy via deubiquitinating TRIM21.

Rationale: Cardiac hypertrophy is an important pathological basis for heart failure. Most physiological activities of cardiomyocytes are regulated by proteins and their post-translational modification. Deubiquitinating enzymes (DUBs) are involved in protein stability maintenance and closely related to myocardial hypertrophy. In this study, we aimed to clarify the regulatory role of a DUB, ubiquitin-specific peptidase 28 (USP28), in cardiac hypertrophy and explore the molecular mechanism behind. Methods: Transcriptome and single-cell mRNA sequencing was used to demonstrate the association of USP28 and cardiac hypertrophy. Cardiomyocyte-specific USP28 knockout mice (USP28CKO) were subjected to angiotensin II (Ang II) infusion or transverse aortic constriction (TAC) models. Coimmunoprecipitation combined mass spectrum analysis (Co-IP/MS) was applied to screen out the substrate of USP28. Results: We first showed the up-regulation of USP28 in cardiac hypertrophy, and its cellular localization of cardiomyocytes. USP28CKO protects mouse heart against Ang II- or TAC-induced cardiac dysfunction and hypertrophy. Mechanistically, we identified tripartite motif-containing protein 21 (TRIM21) as the potential substrate of USP28 by Co-IP/MS analysis. Cardiomyocyte USP28 deubiquitinates and stabilizes TRIM21 to negatively regulate nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant response, increasing oxidative stress in cardiomyocytes and promoting cardiac hypertrophy and injury. Finally, using a selective USP28 inhibitor Otilonium Bromide, we confirmed the therapeutic effect of pharmacological inhibition of USP28 against TAC-induced established hypertrophic heart failure. Conclusion: Our study illustrates a cardiomyocyte-specific USP28-TRIM21 axis in regulating hypertrophic cardiomyopathy and presents USP28 as a potential target for the treatment of cardiac hypertrophy.

Two-pore channels (TPCs) acts as a hub for excitation-contraction coupling, metabolism and cardiac hypertrophy signalling

Ca2+ signaling is essential for cardiac contractility and excitability in heart function and remodeling. Intriguingly, little is known about the role of a new family of ion channels, the endo-lysosomal non-selective cation “two-pore channel” (TPCs) in heart function. Here we have used double TPC knock-out mice for the 1 and 2 isoforms of TPCs (Tpcn1/2−/−) and evaluated their cardiac function. Doppler-echocardiography unveils altered left ventricular (LV) systolic function associated with a LV relaxation impairment. In cardiomyocytes isolated from Tpcn1/2−/- mice, we observed a reduction in the contractile function with a decrease in the sarcoplasmic reticulum Ca2+ content and a reduced expression of various key proteins regulating Ca2+ stores, such as calsequestrin. We also found that two main regulators of the energy metabolism, AMP-activated protein kinase and mTOR, were down regulated. We found an increase in the expression of TPC1 and TPC2 in a model of transverse aortic constriction (TAC) mice and in chronically isoproterenol infused WT mice. In this last model, adaptive cardiac hypertrophy was reduced by Tpcn1/2 deletion. Here, we propose a central role for TPCs and lysosomes that could act as a hub integrating information from the excitation-contraction coupling mechanisms, cellular energy metabolism and hypertrophy signaling.

A novel animal model of neuropathic corneal pain-the ciliary nerve constriction model.

Neuropathic pain arises as a result of peripheral nerve injury or altered pain processing within the central nervous system. When this phenomenon affects the cornea, it is referred to as neuropathic corneal pain (NCP), resulting in pain, hyperalgesia, burning, and photoallodynia, severely affecting patients' quality of life. To date there is no suitable animal model for the study of NCP. Herein, we developed an NCP model by constriction of the long ciliary nerves innervating the eye. Mice underwent ciliary nerve constriction (CNC) or sham procedures. Safety was determined by corneal fluorescein staining to assess ocular surface damage, whereas Cochet-Bonnet esthesiometry and confocal microscopy assessed the function and structure of corneal nerves, respectively. Efficacy was assessed by paw wipe responses within 30 seconds of applying hyperosmolar (5M) saline at Days 3, 7, 10, and 14 post-constriction. Additionally, behavior was assessed in an open field test (OFT) at Days 7, 14, and 21. CNC resulted in significantly increased response to hyperosmolar saline between groups (p < 0.0001), demonstrating hyperalgesia and induction of neuropathic pain. Further, animals that underwent CNC had increased anxiety-like behavior in an open field test compared to controls at the 14- and 21-Day time-points (p < 0.05). In contrast, CNC did not result in increased corneal fluorescein staining or decreased sensation as compared to sham controls (p > 0.05). Additionally, confocal microscopy of corneal whole-mounts revealed that constriction resulted in only a slight reduction in corneal nerve density (p < 0.05), compared to naïve and sham groups. The CNC model induces a pure NCP phenotype and may be a useful model for the study of NCP, recapitulating features of NCP, including hyperalgesia in the absence of ocular surface damage, and anxiety-like behavior.