Angiotensin II induces apoptosis of cardiac microvascular endothelial cells via regulating PTP1B/PI3K/Akt pathway

Sox17 protects human brain microvascular endothelial cells from AngII-induced injury by regulating autophagy and apoptosis

Intracranial aneurysm (IA), is a localized dilation of the intracranial arteries, the rupture of which is catastrophic. Hypertension is major IA risk factor that mediates endothelial cell damage. Sox17 is highly expressed in intracranial vascular endothelial cells, and GWAS studies indicate that its genetic alteration is one of the major genetic risk factors for IA. Vascular endothelial cell injury plays a vital role in the pathogenesis of IA. The genetic ablation of Sox17 plus hypertension induced by AngII can lead to an increased incidence of intracranial aneurysms had tested in the previous animal experiments. In order to study the underlying molecular mechanisms, we established stable Sox17-overexpressing and knockdown cell lines in human brain microvascular endothelial cells (HBMECs) first. Then flow cytometry, western blotting, and immunofluorescence were employed. We found that the knockdown of Sox17 could worsen the apoptosis and autophagy of HBMECs caused by AngII, while overexpression of Sox17 had the opposite effect. Transmission electron microscopy displayed increased autophagosomes after the knockdown of Sox17 in HBMECs. The RNA-sequencing analysis shown that dysregulation of the Sox17 gene was closely associated with the autophagy-related pathways. Our study suggests that Sox17 could protect HBMECs from AngII-induced injury by regulating autophagy and apoptosis.

Regulation of optimized new Shengmai powder on cardiomyocyte apoptosis and ferroptosis in ischemic heart failure rats: The mediating role of phosphatidylinositol-3-kinase/protein kinase B/tumor protein 53 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Optimized New Shengmai Powder (ONSMP) is a sophisticated traditional Chinese medicinal formula renowned for bolstering vital energy, optimizing blood circulation, and mitigating fluid retention. After years of clinical application, ONSMP has shown a significant impact in improving myocardial injury and cardiac function and has a positive effect on treating heart failure. However, many unknowns exist about the molecular biological mechanisms of how ONSMP exerts its therapeutic effects, which require further research and exploration.

AIM OF THE STUDY

Exploring the potential molecular biological mechanisms by which ONSMP ameliorates cardiomyocyte apoptosis and ferroptosis in ischemic heart failure (IHF).

MATERIALS AND METHODS

First, we constructed a rat model of IHF by inducing acute myocardial infarction through surgery and using echocardiography, organ coefficients, markers of heart failure, antioxidant markers, and histopathological examination to assess the effects of ONSMP on cardiomyocyte apoptosis and ferroptosis in IHF rats. Next, we used bioinformatics analysis techniques to analyze the active components, signaling pathways, and core targets of ONSMP and calculated the interactions between core targets and corresponding elements. Finally, we detected the positive expression of apoptosis and ferroptosis markers and core indicators of signaling pathways by immunohistochemistry; detected the mean fluorescence intensity of core indicators of signaling pathways by immunofluorescence; detected the protein expression of signaling pathways and downstream effector molecules by western blotting; and detected the mRNA levels of p53 and downstream effector molecules by quantitative polymerase chain reaction.

RESULTS

ONSMP can activate the Ser83 site of ASK by promoting the phosphorylation of the PI3K/AKT axis, thereby inhibiting the MKK3/6-p38 axis and the MKK4/7-JNK axis signaling to reduce p53 expression, and can also directly target and inhibit the activity of p53, ultimately inhibiting p53-mediated mRNA and protein increases in PUMA, SAT1, PIG3, and TFR1, as well as mRNA and protein decreases in SLC7A11, thereby inhibiting cardiomyocyte apoptosis and ferroptosis, effectively improving cardiac function and ventricular remodeling in IHF rat models.

CONCLUSION

ONSMP can inhibit cardiomyocyte apoptosis and ferroptosis through the PI3K/AKT/p53 signaling pathway, delaying the development of IHF.

Top Five Stories of the Cellular Landscape and Therapies of Atherosclerosis: Current Knowledge and Future Perspectives

Atherosclerosis (AS) is characterized by impairment and apoptosis of endothelial cells, continuous systemic and focal inflammation and dysfunction of vascular smooth muscle cells, which is documented as the traditional cellular paradigm. However, the mechanisms appear much more complicated than we thought since a bulk of studies on efferocytosis, transdifferentiation and novel cell death forms such as ferroptosis, pyroptosis, and extracellular trap were reported. Discovery of novel pathological cellular landscapes provides a large number of therapeutic targets. On the other side, the unsatisfactory therapeutic effects of current treatment with lipid-lowering drugs as the cornerstone also restricts the efforts to reduce global AS burden. Stem cell- or nanoparticle-based strategies spurred a lot of attention due to the attractive therapeutic effects and minimized adverse effects. Given the complexity of pathological changes of AS, attempts to develop an almighty medicine based on single mechanisms could be theoretically challenging. In this review, the top stories in the cellular landscapes during the initiation and progression of AS and the therapies were summarized in an integrated perspective to facilitate efforts to develop a multi-targets strategy and fill the gap between mechanism research and clinical translation. The future challenges and improvements were also discussed.

Treadmill running increases the calcium sensitivity of myofilaments in diabetic rats

The cardiovascular benefits of regular exercise are unequivocal, yet patients with type 2 diabetes respond poorly to exercise due to a reduced cardiac reserve. The contractile response of diabetic cardiomyocytes to beta-adrenergic stimulation is attenuated, which may result in altered myofilament calcium sensitivity and post-translational modifications of cardiac troponin I (cTnI). Treadmill running increases myofilament calcium sensitivity in non‑diabetic rats, and thus we hypothesized that endurance training would increase calcium sensitivity of diabetic cardiomyocytes and alter site-specific phosphorylation of cTnI. Calcium sensitivity, or pCa₅₀, was measured in Zucker Diabetic Fatty (ZDF) non-diabetic (nDM) and diabetic (DM) rat hearts after 8 weeks of either a sedentary (SED) or progressive treadmill running (TR) intervention. Skinned cardiomyocytes were connected to a capacitance-gauge transducer and a torque motor to measure force as a function of pCa (‑log[Ca²⁺]). Specific phospho-sites on cTnI and O‑GlcNAcylation were quantified by immunoblot and total protein phosphorylation by fluorescent gel staining (ProQ Diamond). The novel finding in this study was that training increased pCa₅₀ in both DM and nDM cardiomyocytes (p = 0.009). Phosphorylation of cTnI amino acid residues Ser23/24, a crucial protein kinase A site, and Threonine (Thr)144, was lower in DM hearts, but there was no effect of training on site-specific phosphorylation. Additionally, total phosphorylation and O-GlcNAcylation levels were not different between SED and TR groups. These findings suggest that regular exercise may benefit the diabetic heart by specifically targeting myofilament contractile function.

Cerebro-Cardiovascular Risk, Target Organ Damage, and Treatment Outcomes in Primary Aldosteronism

Primary aldosteronism (PA) is the most common type of endocrine hypertension, and numerous experimental and clinical evidence have verified that prolonged exposure to excess aldosterone is responsible for an increased risk of cerebro-cardiovascular events and target organ damage (TOD) in patients with PA. Therefore, focusing on restoring the toxic effects of excess aldosterone on the target organs is very important to reduce cerebro-cardiovascular events. Current evidence convincingly demonstrates that both surgical and medical treatment strategies would benefit cerebro-cardiovascular outcomes and mortality in the long term. Understanding cerebro-cardiovascular risk in PA would help clinical doctors to achieve both early diagnosis and treatment. Therefore, in this review, we will summarize the cerebro-cardiovascular risk in PA, focusing on the TOD of aldosterone, including brain, heart, vascular system, renal, adipose tissues, diabetes, and obstructive sleep apnea (OSA). Furthermore, the various treatment outcomes of adrenalectomy and medical treatment for patients with PA will also be discussed. We hope this knowledge will help improve cerebro-cardiovascular prognosis and reduce the incidence and mortality of cerebro-cardiovascular events in patients with PA.

MEF2 in cardiac hypertrophy in response to hypertension

Hypertension is a globally prevalent pathological condition and an underlying risk factor for the development of cardiac hypertrophy leading to heart failure. Myocyte enhancer factor 2 (Mef2) has been identified as one of the primary effectors of morphological changes in the hypertensive heart, as part of a complex network of molecular signaling controlling cardiac gene expression. Experimental chronic pressure-overload models that mimic hypertension in the mammalian heart lead to the activation of various pathological mechanisms that result in structural changes leading to debilitating cardiac hypertrophy and ultimately heart failure. The purpose here is to survey the literature implicating Mef2 in hypertension induced cardiac hypertrophy, towards illuminating points of interest for understanding and potentially treating heart failure.

Vitamin D/Vitamin D Receptor Signaling Attenuates Skeletal Muscle Atrophy by Suppressing Renin-Angiotensin System

The nutritional level of vitamin D may affect musculoskeletal health. We have reported that vitamin D is a pivotal protector against tissue injuries by suppressing local renin-angiotensin system (RAS). This study aimed to explore the role of the vitamin D receptor (VDR) in the protection against muscle atrophy and the underlying mechanism. A cross-sectional study on participants (n = 1034) in Shanghai (China) was performed to analyze the association between vitamin D level and the risk of low muscle strength as well as to detect the circulating level of angiotensin II (Ang II). In animal studies, dexamethasone (Dex) was applied to induce muscle atrophy in wild-type (WT) and VDR-null mice, and the mice with the induction of muscle atrophy were treated with calcitriol for 10 days. The skeletal muscle cell line C2C12 and the muscle satellite cells were applied in in vitro studies. The increased risk of low muscle strength was correlated to a lower level of vitamin D (adjusted odds ratio [OR] 0.58) accompanied by an elevation in serum Ang II level. Ang II impaired the myogenic differentiation of C2C12 myoblasts as illustrated by the decrease in the area of myotubes and the downregulation of myogenic factors (myosin heavy chain [MHC] and myogenic differentiation factor D [MyoD]). The phenotype of muscle atrophy induced by Dex and Ang II was aggravated by VDR ablation in mice and in muscle satellite cells, respectively, and mediated by RAS and its downstream phosphatidylinositol 3-kinase/protein kinase B/forkhead box O1 (PI3K/Akt/FOXO1) signaling. Calcitriol treatment exhibited beneficial effects on muscle function as demonstrated by the increased weight-loaded swimming time, grip strength, and fiber area, and improved fiber type composition via regulating ubiquitin ligases and their substrates MHC and MyoD through suppressing renin/Ang II axis. Taken together, VDR protects against skeletal muscle atrophy by suppressing RAS. Vitamin D could be a potential agent for the prevention and treatment of skeletal muscle atrophy. © 2021 American Society for Bone and Mineral Research (ASBMR).

High serum angiotensin-converting enzyme 2 activity as a biomarker of frailty in nursing home residents

Angiotensin-converting enzyme (ACE) and angiotensin-converting enzyme 2 (ACE2) are two of the main components of the renin-angiotensin system (RAS). Imbalanced RAS showing lower ACE2 has been associated with increased cardiovascular risk, muscular pathologies, sarcopenia, frailty, other age-related pathologies and a poorer health status. However, its role in aging remains unclear. Thus, the aim of this work was to analyze the serum enzymatic activity of ACE and ACE2, the ACE/ACE2 ratio and its association with anthropometric parameters, blood pressure, physical function, dependence and frailty in older people living in nursing homes. This study is a secondary analysis of baseline data from two randomized clinical trials in a population of 228 older individuals living in nursing homes (Spain). Serum ACE and ACE2 enzymatic activities were measured by fluorimetry. Variables linked to cardiovascular risk, physical function, dependence and frailty were measured using validated tests, indexes and scales. Association between ACE, ACE2 serum activities, the ACE/ACE2 ratio and the rest of the quantitative variables were assessed by Pearson's correlations and by partial correlations controlled by age and sex. The association between serum ACE and ACE2 activities, the ACE/ACE2 ratio and frailty scores was analyzed by generalized linear models with and without controlling for sex and age. Differences in enzymatic activities between sexes and between frail and non-frail individuals were analyzed using Student's t-test and general linear models to control analysis by age and sex. We found that higher serum ACE2 activity was associated with a higher body mass index, worse physical function, greater dependence and increased frailty. This association is consistent with the elevation of circulating ACE2 in certain pathological conditions and in line with RAS deregulation in muscular dystrophies. Serum ACE2 activity, in combination with other molecules, could be proposed as a biomarker of poor physical function, higher dependence and frailty.

Signaling Pathway in the Osmotic Resistance Induced by Angiotensin II AT2 Receptor Activation in Human Erythrocytes

Background

Angiotensin II regulates blood volume via AT1 (AT1R) and AT2 (AT2R) receptors. As cell integrity is an important feature of mature erythrocyte, we sought to evaluate, in vitro, whether angiotensin II modulates resistance to hemolysis and the signaling pathway involved.

Methods

Human blood samples were collected and hemolysis assay and angiotensin II signaling pathway profiling in erythrocytes were done.

Results

Hemolysis assay created a hemolysis curve in presence of Ang II in several concentrations (10^-6 M, 10^-8 M, 10^-10 M, 10^-12 M). Angiotensin II demonstrated protective effect, both in osmotic stressed and physiological situations, by reducing hemolysis in NaCl 0.4% and 0.9%. By adding receptors antagonists (losartan, AT1R antagonist and PD 123319, AT2R antagonist) and/or signaling modulators for AMPK, Akt/PI3K, p38 and PKC we showed the protective effect was enhanced with losartan and abolished with PD 123319. Also, we showed activation of p38 as well as PI3K/Akt pathways in this system.

Conclusion

Ang II protects human erythrocytes from hypo-osmotic conditions-induced hemolysis by activating AT2 receptors and triggering intracellular pathways.

Protein tyrosine phosphatase 1B inhibition improves endoplasmic reticulum stress‑impaired endothelial cell angiogenic response: A critical role for cell survival

Endoplasmic reticulum (ER) stress contributes to endothelial dysfunction, which is the initial step in atherogenesis. Blockade of protein tyrosine phosphatase (PTP)1B, a negative regulator of insulin receptors that is critically located on the surface of ER membrane, has been found to improve endothelial dysfunction. However, the role of ER stress and its related apoptotic sub‑pathways in PTP1B‑mediated endothelial dysfunction, particularly its angiogenic capacity, have not yet been fully elucidated. Thus, the present study aimed to investigate the impact of PTP1B suppression on ER stress‑mediated impaired angiogenesis and examined the contribution of apoptotic signals in this process. Endothelial cells were exposed to pharmacological ER stressors, including thapsigargin (TG) or 1,4‑dithiothreitol (DTT), in the presence or absence of a PTP1B inhibitor or small interfering (si)RNA duplexes. Then, ER stress, angiogenic capacity, cell cycle, apoptosis and the activation of key apoptotic signals were assessed. It was identified that the inhibition of PTP1B prevented ER stress caused by DTT and TG. Moreover, ER stress induction impaired the activation of endothelial nitric oxide synthase (eNOS) and the angiogenic capacity of endothelial cells, while PTP1B inhibition exerted a protective effect. The results demonstrated that blockade or knockdown of PTP1B prevented ER stress‑induced apoptosis and cell cycle arrest. This effect was associated with reduced expression levels of caspase‑12 and poly (ADP‑Ribose) polymerase 1. PTP1B blockade also suppressed autophagy activated by TG. The current data support the critical role of PTP1B in ER stress‑mediated endothelial dysfunction, characterized by reduced angiogenic capacity, with an underlying mechanism involving reduced eNOS activation and cell survival. These findings provide evidence of the therapeutic potential of targeting PTP1B in cardiovascular ischemic conditions.

Exposure to mono (2-ethylhexyl) phthalate facilitates apoptosis and pyroptosis of human endometrial microvascular endothelial cells through NLRP3 inflammasome

Mono (2-ethylhexyl) phthalate (MEHP) is a major metabolite of di (2-ethylhexyl) phthalate (DEHP). This study aimed to observe the toxic effect of MEHP on human endometrial microvascular endothelial cells (HEMECs) and its potential molecular mechanism. HEMECs were exposed to different concentrations of MEHP (0, 50, 100, and 200 nM). Cell viability and apoptosis were assessed by cell counting kit-8 (CCK-8) and flow cytometry assays. Western blot was performed to examine the expression of apoptosis-related proteins (Bcl-2, Bax, and Caspase-3). Moreover, the expression of pyroptosis-related Caspase-1 was detected by western blot and immunofluorescence assays. Lactate dehydrogenase (LDH) release levels were evaluated in HEMECs treated with MEHP and/or Caspase-1 inhibitor Ac-YVAD-CHO. After exposure to MEHP, NLRP3 expression was examined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot. LDH release and apoptosis levels were tested in HEMECs induced by MEHP and/or siNLRP3. MEHP significantly induced cell viability and inhibited apoptosis for HEMECs, with a concentration-dependent manner. Furthermore, Bcl-2/Bax ratio was distinctly reduced and Caspase-3 expression was increased in HEMECs after exposure to MEHP. Western blot and immunofluorescence results confirmed that MEHP markedly augmented Caspase-1 expression in HEMECs. Furthermore, LDH release levels were fortified in HEMECs treated with MEHP, which were improved following cotreatment with Ac-YVAD-CHO. At the mRNA and protein levels, NLRP3 expression was prominently increased in HEMECs exposed to MEHP. NLRP3 knockdown markedly ameliorated the increase in LDH release and apoptosis induced by MEHP exposure in HEMECs. Our findings suggested that exposure to MEHP facilitates apoptosis and pyroptosis of HEMECs through NLRP3 inflammasome.