Integrin αV mediated activation of myofibroblast via mechanoparacrine of transforming growth factor β1 in promoting fibrous scar formation after myocardial infarction

BACKGROUND

Myocardial infarction (MI) dramatically changes the mechanical stress, which is intensified by the fibrotic remodeling. Integrins, especially the αV subunit, mediate mechanical signal and mechanoparacrine of transforming growth factor β1 (TGF-β1) in various organ fibrosis by activating CFs into myofibroblasts (MFBs). We investigated a possible role of integrin αV mediated mechanoparacrine of TGF-β1 in MFBs activation for fibrous reparation in mice with MI.

METHODS

Heart samples from MI, sham, or MI plus cilengitide (14 mg/kg, specific integrin αV inhibitor) treated mice, underwent functional and morphological assessments by echocardiography, and histochemistry on 7, 14 and 28 days post-surgery. The mechanical and ultrastructural changes of the fibrous scar were further evaluated by atomic mechanics microscope (AFM), immunofluorescence, second harmonic generation (SHG) imaging, polarized light and scanning electron microscope, respectively. Hydroxyproline assay was used for total collagen content, and western blot for protein expression profile examination. Fibroblast bioactivities, including cell shape, number, Smad2/3 signal and expression of extracellular matrix (ECM) related proteins, were further evaluated by microscopic observation and immunofluorescence in polyacrylamide (PA) hydrogel with adjustable stiffness, which was re-explored in fibroblast cultured on stiff matrix after silencing of integrin αV. The content of total and free TGF-β1 was tested by enzyme-linked immunosorbent assay (ELISA) in both infarcted tissue and cell samples.

RESULT

Increased stiffness with heterogeneity synchronized with integrin αV and alpha smooth muscle actin (α-SMA) positive MFBs accumulation in those less mature fibrous areas. Cilengitide abruptly reduced collagen content and disrupted collagen alignment, which also decreased TGF-β1 bioavailability, Smad2/3 phosphorylation, and α-SMA expression in the fibrous area. Accordingly, fibroblast on stiff but not soft matrix exhibited obvious MFB phenotype, as evidenced by enlarged cell, hyperproliferation, well-developed α-SMA fibers, and elevated ECM related proteins, while silencing of integrin αV almost abolished this switch via attenuating paracrine of TGF-β1 and nuclear translocation of Smad2/3.

CONCLUSION

This study illustrated that increased tissue stiffness activates CFs into MFBs by integrin αV mediated mechanoparacrine of TGF-β1, especially in immature scar area, which ultimately promotes fibrous scar maturation.

Notoginsenoside R1-loaded mesoporous silica nanoparticles targeting the site of injury through inflammatory cells improves heart repair after myocardial infarction

Notoginsenoside R1 (NGR1) is the main monomeric component extracted from the dried roots and rhizomes of Panax notoginseng, and exerts pharmacological action against myocardial infarction (MI). Owing to the differences in compound distribution, absorption, and metabolism in vivo, exploring a more effective drug delivery system with a high therapeutic targeting effect is crucial. In the early stages of MI, CD11b-expressing monocytes and neutrophils accumulate at infarct sites. Thus, we designed a mesoporous silica nanoparticle-conjugated CD11b antibody with loaded NGR1 (MSN-NGR1-CD11b antibody), which allowed NGR1 precise targeted delivery to the heart in a noninvasively manner. By increasing targeting to the injured myocardium, intravenous injection of MSN-NGR1-CD11b antibody nanoparticle in MI mice improved cardiac function and angiogenesis, reduced cell apoptosis, and regulate macrophage phenotype and inflammatory factors and chemokines. In order to further explore the mechanism of NGR1 protecting myocardium, cell oxidative stress model and oxygen-glucose deprivation (OGD) model were established. NGR1 protected H9C2 cells and primary cardiomyocytes against oxidative injury induced by H₂O₂ and OGD treatment. Further network pharmacology and molecular docking analyses suggested that the AKT, MAPK and Hippo signaling pathways were involved in the regulation of NGR1 in myocardial protection. Indeed, NGR1 could elevate the levels of p-Akt and p-ERK, and promote the nuclear translocation of YAP. Furthermore, LY294002 (AKT inhibitor), U0126 (ERK1/2 inhibitor) and Verteporfin (YAP inhibitor) administration in H9C2 cells indicated the involvement of AKT, MAPK and Hippo signaling pathways in NGR1 effects. Meanwhile, MSN-NGR1-CD11b antibody nanoparticles enhanced the activation of AKT and MAPK signaling pathways and the nuclear translocation of YAP at the infarcted site. Our research demonstrated that MSN-NGR1-CD11b antibody nanoparticle injection after MI enhanced the targeting of NGR1 to the infarcted myocardium and improved cardiac function. More importantly, our pioneering research provides a new strategy for targeting drug delivery systems to the ischemic niche.

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CD11b antibody modification enhanced the target of Mesoporous silica nanoparticles to injured myocardium.

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NGR1 promoted the survival of H9C2 against oxidative stress injury through PIK3/AKT, MAPK/ERK and YAP signaling pathways.

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NGR1 protected neonatal and adult cardiomyocytes from H₂O₂ and OGD induced oxidative stress damage.

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MSN-NGR1-CD11b antibody nanoparticles improved heart function by activating PIK3/AKT, MAPK/ERK and YAP signaling pathways.

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MSN-NGR1-CD11b antibody nanoparticles induced M2 polarization of macrophages and regulated the inflammatory factors.

Stachydrine hydrochloride ameliorates cardiac hypertrophy through CaMKII/HDAC4/MEF2C signal pathway

Stachydrine hydrochloride (Sta), an activated alkaloid, is isolated from traditional Chinese medicine Yimucao. In previous studies, the cardioprotective effects of Sta were found in our laboratory. However, the underling mechanisms of Sta is not fully elucidated. The aim of this study was to provide a detailed account of the anti-hypertrophic effects of Sta on transcriptional regulation. In vivo, C57BL/6J mice were subjected to transverse aortic constriction (TAC) and were orally treated with Sta. Morphological assessments, echocardiographic parameters, histological analyses and immunofluorescence were used to evaluate cardiac hypertrophy. In vitro, cardiomyocytes were stimulated by phenylephrine (PE), and cell surface and hypertrophy markers were tested by immunofluorescence and real-time polymerase chain reaction (RT-PCR). Moreover, western blotting, RT-PCR and luciferase reporter genes were used to assess the expression of proteins, mRNA and the activity of the CaMKII/HDAC4/MEF2C signal pathway in vivo and in vitro. We found that Sta blocked cardiac hypertrophy induced by pressure overload. We also demonstrated that Sta inhibited nuclear export or promoted nuclear import of HDAC4 through regulation of p-CaMKII, and it further improved the repression of MEF2C. Taken together, our findings demonstrated that Sta ameliorates cardiac hypertrophy through CaMKII/HDAC4/MEF2C signal pathway.

Treatment of Masked Hypertension with a Chinese Herbal Formula

Background:

Masked hypertension is associated with adverse cardiovascular outcomes. Nonetheless, no randomized controlled trials exist in the treatment of masked hypertension. The aim of this randomized, placebo-controlled trial was to investigate the efficacy and safety of blood pressure (BP)–lowering treatment with a Chinese herbal formula, gastrodia-uncaria granules, in patients with masked hypertension.

Methods:

Patients with an office BP of <140/90 mm Hg and daytime ambulatory BP of 135 to 150 mm Hg systolic or 85 to 95 mm Hg diastolic were randomly assigned 1:1 to the treatment of gastrodia-uncaria granules or placebo 5 to 10 g twice daily for 4 weeks. The primary efficacy variable was the change in daytime ambulatory BP.

Results:

At baseline, office and daytime BP of the 251 participants (mean age, 50.4 years; 53.4% men; mean body mass index 24.5 kg/m 2 ; and 2.8%, 1.6%, and 30.7% with cardiovascular disease, diabetes, and smoking, respectively) averaged 129/82 and 135/89 mm Hg, respectively. In the intention-to-treat analysis, daytime systolic/diastolic BP was reduced by 5.44/3.39 and 2.91/1.60 mm Hg in the gastrodia-uncaria granules and placebo groups, respectively. The between-group difference in BP reductions was significant for the daytime (2.52/1.79 mm Hg; P ≤0.025) and 24-hour BP (2.33/1.49 mm Hg; P ≤0.012), but not for the clinic and nighttime BPs ( P ≥0.162). The per-protocol analysis in 229 patients produced similar results. Only 1 adverse event (sleepiness during the day) was reported, and no serious adverse event occurred.

Conclusions:

BP-lowering treatment with Chinese traditional medicine gastrodia-uncaria granules is efficacious for patients with masked hypertension.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02156024.

Stachydrine hydrochloride alleviates pressure overload-induced heart failure and calcium mishandling on mice

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine Leonurus japonicus Houtt. has a long history in the treatment of cardiovascular diseases. Stachydrine hydrochloride, the main bioactive ingredient extracted from Leonurus japonicus Houtt., has been shown to have cardioprotective effects. However, the underlying mechanisms of stachydrine hydrochloride haven't been comprehensively studied so far.

AIM OF THE STUDY

The aim of this study was to investigate the protective role of stachydrine hydrochloride in heart failure and elucidate its possible mechanisms of action.

MATERIALS AND METHODS

In vivo, transverse aorta constriction was carried out in C57BL/6J mice, and thereafter, 7.2 mg/kg telmisartan (a selective AT1R antagonist as positive control) and 12 mg/kg stachydrine hydrochloride was administered daily intragastrically for 4 weeks. Cardiac function was evaluated by assessing morphological changes as well as echocardiographic and haemodynamic parameters. In vitro, neonatal rat cardiomyocytes or adult mice cardiomyocytes were treated with stachydrine hydrochloride and challenged with phenylephrine (α-AR agonist). Ventricular myocytes were isolated from the hearts of C57BL/6J mice by Langendorff crossflow perfusion system. Intracellular calcium was measured by an ion imaging system. The length and movement of sarcomere were traced to evaluate the systolic and diastolic function of single myocardial cells.

RESULTS

Stachydrine hydrochloride improved the cardiac function and calcium transient amplitudes, and inhibited the SR leakage and the amount of sparks in cardiac myocytes isolated from TAC mice. We also demonstrated that stachydrine hydrochloride could ameliorated phenylephrine-induced enhance in sarcomere contraction, calcium transients and calcium sparks. Moreover, our data shown that stachydrine hydrochloride blocked the hyper-phosphorylation of CaMKII, RyR2, PLN, and prevented the disassociation of FKBP12.6 from RyR2.

CONCLUSION

Our results suggest that stachydrine hydrochloride exerts beneficial therapeutic effects against heart failure. These cardioprotective effects may be associated with the regulation of calcium handling by stachydrine hydrochloride through inhibiting the hyper-phosphorylation of CaMKII.

Note: Application of a novel 2(3HUS+S) parallel manipulator for simulation of hip joint motion

In the paper, a novel 2(3HUS+S) parallel manipulator, which has two moving platforms, is proposed. The parallel manipulator is adopted to simulate hip joint motion and can conduct an experiment for two hip joints simultaneously. Motion experiments are conducted in the paper, and the recommended hip joint motion curves from ISO14242 and actual hip joint motions during jogging and walking are selected as the simulated motions. The experimental results indicate that the 2(3HUS+S) parallel manipulator can realize the simulation of many kinds of hip joint motions without changing the structure size.

Persistence of Masked Hypertension in Chinese Patients

BACKGROUND

Masked hypertension (MH) has 10-15% prevalence and carries risk similar to that of sustained hypertension, but its short-term persistence remains uncertain.

METHODS

Forty-five patients with MH (mean age 52.2 years; 37.8% women) were enrolled in the placebo arm of a randomized clinical trial of Chinese medicine (NCT02156024) and followed up for 4 weeks. MH was office normotension (<140/90mm Hg) and daytime (8:00-18:00) hypertension (≥135/85mm Hg).

RESULTS

At enrolment, office and daytime systolic/diastolic blood pressure (BP) averaged 129.0/80.6mm Hg and 132.9/88.9mm Hg, respectively. Daytime BP thresholds for MH were met in 5 patients (11.1%) for systolic BP, in 25 (55.6%) for diastolic BP and in 15 (33.3%) for both. At follow-up, systolic and diastolic BP had not changed compared with baseline (P ≥ 0.12), except for a 2.1mm Hg decrease in office systolic BP (P = 0.049). MH remained present in 28 patients (62.2%; 95% CI, 48.1-76.3%), whereas 13 (28.9%; 15.7-42.1%) and 4 (8.9%; 0.6-17.2%) converted to normotension (daytime BP <135/85mm Hg) or sustained hypertension (office BP ≥140/90mm Hg), respectively. Substituting daytime by 24-hour BP, using 130/80mm Hg as threshold, produced consistent results. Systolic office BP at baseline independently predicted persistence of MH or progression to sustained hypertension at 4 weeks (odds ratio per 1 - SD increase, 3.49; 95% CI, 1.06-11.2; P = 0.04).

CONCLUSIONS

The information that MH persists over 4 weeks in over two-thirds of this sample of patients should inform future clinical trials and guidelines.

Effects of stachydrine on norepinephrine-induced neonatal rat cardiac myocytes hypertrophy and intracellular calcium transients

Background

Leonurus heterophyllus sweet has been suggested to have cardioprotective effects against heart diseases, including ischemic diseases and ventricular remodeling. However, the active ingredients of the herb and the underlying mechanisms are poorly understood. The aim of the present study was to investigate the effects of stachydrine (STA), a major constituent of Leonurus heterophyllus sweet, on norepinephrine (NE) induced hypertrophy and the changes of calcium transients in neonatal rat cardiomyocytes.

Methods

Ventricular myocytes from 1-day-old Wistar rats were isolated and cultured in DMEM/F12 with 1 μmol/L norepinephrine in the presence or absence of 10 μmol/L STA for 72 h. Cardiomyocytes hypertrophy was evaluated by cell surface area, total protein/DNA content, β/α-MHC mRNA ratio. While calcium handling function was evaluated by Ca²⁺-transient amplitude and decay, SERCA2a activity and expression, PLN expression and phosphorylation. β1-adrenergic receptor system activation was evaluated by the content of cAMP and the activation of PKA.

Results

NE treatment increases the cell surface area, protein synthesis, the expression level of β-MHC and β/α-MHC ratio. These effects were attenuated by STA. NE-induced hypertrophy was associated with increased Ca²⁺-transient amplitude, accelerated decay of the Ca²⁺-transient, increased phospholamban expression, hyper-phosphorylation at both the serine-16 and threonine-17 residues, increased intracellular cAMP level, and PKA overactivation. All of which were significantly inhibited by STA.

Conclusion

These data suggest that STA attenuates norepinephrine-induced cardiomyocyte hypertrophy and has potential protective effects against β-adrenergic receptor induced Ca²⁺ mishandling.