TNF-α-Mediated Endothelial Cell Apoptosis Is Rescued by Hydrogen Sulfide

GYY4137 ameliorates blood brain barrier damage by inhibiting autophagy mediated occludin degradation in cardiac arrest and resuscitation

Cardiopulmonary resuscitation (CPR) after cardiac arrest (CA) is an important cause of neurological impairment and leads to considerable morbidity and mortality. The stability of the blood-brain barrier (BBB) is crucial for minimizing secondary neurological damage and improving long-term prognosis. However, the precise mechanisms and regulatory pathways that contribute to BBB dysfunction after CPR remain elusive. GYY4137 is an innovative hydrogen sulfide slow-release agent with excellent properties as a hydrogen sulfide substitute. The aim of this study was to investigate the protective effects of GYY4137 on CA/CPR and the underlying mechanisms of BBB protection. The effects of GYY4137 on systemic inflammation, BBB integrity, and autophagy were evaluated using a mouse CA/CPR model. The underlying mechanisms of occludin changes associated with GYY4137 were investigated using oxygen-glucose deprivation / reoxygenation (OGD/R) model. ELISA, neurological function and other tests showed that GYY4137 ameliorates systemic inflammation and neurological prognosis. Western blotting, transwell migration and tube formation assays showed that GYY4137 improves BBB function both in vivo and in vitro. The detection of autophagy flow and protein degradation pathways showed the inhibition of occludin reduction by GYY4137 was mainly achieved by suppressing autophagy mediated degradation. Taken together, GYY4137 may improve BBB dysfunction following CPR by increasing occludin content. This effect was achieved by inhibiting autophagic degradation rather than promoting synthesis. GYY4137 also mitigated systemic inflammation and improved neurological outcomes after CA/CPR. In summary, our study provides valuable insights into protecting the integrity of BBB and improving neurological outcomes after CPR.

Stimulation of Calcium/NOS/CK1α Signaling by Cedrol Triggers Eryptosis and Hemolysis in Red Blood Cells

Background

Cedrol (CRL) is a sesquiterpene alcohol present in the essential oils of coniferous trees including Cupressus and Juniperus genera. CRL has shown potent anticancer activity by virtue of apoptosis. Red blood cells (RBCs), although devoid of mitochondria and nucleus, can undergo hemolysis and eryptosis which contribute to chemotherapy-induced anemia (CIA). In this work, we explored the hemolytic and eryptotic potential of CRL in human RBCs as a safety assessment of the sesquiterpene as an anticancer agent.

Methods

RBCs from healthy donors were treated with anticancer concentrations of CRL for 24 h at 37°C with varying experimental manipulations. Hemolysis was photometrically assessed by measuring hemoglobin release whereas flow cytometry was employed to detect phosphatidylserine (PS) exposure by annexin-V-FITC, intracellular Ca2+ by Fluo4/AM, cell volume by forward scatter (FSC), and oxidative stress by 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA).

Results

Significant, concentration-responsive hemolysis was noted upon CRL exposure with concomitant K+, LDH, and AST leakage. CRL also significantly increased annexin-V-positive cells and Fluo4 fluorescence and reduced FSC. Moreover, the cytotoxicity of CRL was significantly ameliorated in the presence of L-NAME, D4476, and PEG 8,000 but was aggravated by urea and sucrose.

Conclusion

CRL stimulates hemolysis and eryptosis characterized by PS exposure, Ca2+ overload, and cell shrinkage. The hemolytic activity of CRL was mediated through nitric oxide synthase and casein kinase 1α. Blocking either enzyme may attenuate the toxicity of CRL to RBCs and prevent undesirable side effects associated with its anticancer applications.

Oxidative Stress and the Nrf2/PPARγ Axis in the Endometrium: Insights into Female Fertility

Successful pregnancy depends on precise molecular regulation of uterine physiology, especially during the menstrual cycle. Deregulated oxidative stress (OS), often influenced by inflammatory changes but also by environmental factors, represents a constant threat to this delicate balance. Oxidative stress induces a reciprocally regulated nuclear factor erythroid 2-related factor 2/peroxisome proliferator-activated receptor-gamma (Nrf2/PPARγ) pathway. However, increased PPARγ activity appears to be a double-edged sword in endometrial physiology. Activated PPARγ attenuates inflammation and attenuates OS to restore redox homeostasis. However, it also interferes with physiological processes during the menstrual cycle, such as hormonal signaling and angiogenesis. This review provides an elucidation of the molecular mechanisms that support the interplay between PPARγ and OS. Additionally, it offers fresh perspectives on the Nrf2/PPARγ pathway concerning endometrial receptivity and its potential implications for infertility.

IL-33 Suppresses the Progression of Atherosclerosis via the ERK1/2-IRF1-VCAM-1 Pathway

PURPOSE

This study was designed to explore the effects of interleukin 33 (IL-33) on the progression of atherosclerosis and the possible mechanism.

METHODS

The adhesion assay was performed on isolated peripheral blood mononuclear cells (PBMCs) and human umbilical vein endothelial cells (HUVEC). The expression of proteins and messenger RNA (mRNA) were detected by western blot and quantitative real-time polymerase chain reaction (PCR), including intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and P-selectin. The effect of IL-33 on the interaction of growth stimulation expressed gene 2 (ST2) with myeloid differentiation factor 88 (MyD88) and interleukin-1 receptor-associated kinase (IRAK) 1/4 were investigated using co-immunoprecipitation assay. An apolipoprotein (Apo) E-/- mice model was used to confirm the effect of IL-33 on atherosclerosis progression. Area of plaques was recorded by hematoxylin-eosin (H&E) staining. The severity of atherosclerosis plaque was evaluated using immunohistochemistry assay, and lipid accumulation was measured by an oil red O staining. In contrast, western blot was performed to detect the expression levels of VCAM-1, extracellular signal-regulated kinase (ERK) 1/2, and interferon regulatory factor 1 (IRF1).

RESULTS

Our study observed that IL-33 suppressed cell adhesion and the expression of VCAM-1 in tumor necrosis factor-α (TNF-α) exposed HUVEC. Moreover, the addition of IL-33 significantly inhibited the expression of IRF1 and the binding level of IRF1 to VCAM-1 and also promoted the phosphorylation level of IRAK1/4 and ERK1/2 compared to TNF-α-stimulated HUVEC. The ST2 neutralizing antibody or ERK pathway inhibitor SCH772984 reversed the regulatory effects of IL-33 on HUVEC, suggesting that IL-33 suppressed IRF1 and VCAM-1 dependent on binding to ST2 and activating the ERK1/2 signaling pathway. Further investigation in vivo confirmed that IL-33 decreased the expressions of IRF1 and VCAM-1 by activating the phosphorylation of ERK1/2 in the thoracic aorta of Apo E-/- mice.

CONCLUSION

In conclusion, our results demonstrated that IL-33 plays a protective role in the progression of atherosclerosis by inhibiting cell adhesion via the ERK1/2-IRF1-VCAM-1 pathway. This study may provide a potential therapeutic way to prevent the development of atherosclerosis.

RNA sequencing analysis of early-stage atherosclerosis in vascular-on-a-chip and its application for comparing combustible cigarettes with heated tobacco products

Our previous study showed promising results in replicating early-stage atherosclerosis when vascular endothelial cells (VECs) were exposed to cigarette smoke (CS) extract via M0 macrophages. We used an organ-on-a-chip system as an alternative to animal testing to model atherosclerosis, which is a complex disease involving endothelial and immune cell communications. By incorporating macrophages into the vascular-on-a-chip system, we aimed to mimic the indirect effects of inhalable substances, such as CS, on VECs. In the current study, we further examined the suitability of our in vitro system for mimicking early-stage atherosclerosis by transcriptomic analyses of VECs exposed to CS directly or indirectly via macrophages. We also incorporated M1 macrophages to replicate a preexisting inflammatory state. We found a greater number of differentially expressed genes (DEGs) in direct exposure methods than indirect exposure methods. However, a pathway analysis showed that the direct exposure of CS to VECs primarily caused cell death-related pathway alterations, and the "Atherosclerosis Signaling" pathway was predicted to be negatively regulated. Indirect exposure via M0 macrophages similarly showed that the identified DEGs were related to cell death, while the "Atherosclerosis Signaling" pathway was predicted to be activated. In contrast, cell death-related pathway alterations were not observed by indirect exposure of CS to VECs via M1 macrophages, but the pathway perturbations were similar to a pro-inflammatory positive control. In addition, the "Atherosclerosis Signaling" pathway was predicted to be activated in VECs that were indirectly exposed to CS via M1 macrophages. These results suggest that M0 or M1 macrophages contribute to atherogenic transcriptomic changes in VECs, although they affect cell death-related pathways differently. We also used indirect exposure methods to compare the effects of CS and heated tobacco product (HTP) aerosol. Notably, gene expression changes related to atherosclerosis were less pronounced in HTP aerosol-exposed VECs than CS. Our study highlights the utility of the vascular-on-a-chip system with indirect exposure of CS extract via macrophages for replicating atherogenesis and suggests a reduced risk potential of the HTP. This research contributes to advancing alternatives to animal testing for toxicological and disease modeling studies.

The potential role of hydrogen sulfide in cancer cell apoptosis

For a long time, hydrogen sulfide (H2S) has been considered a toxic compound, but recent studies have found that H2S is the third gaseous signaling molecule which plays a vital role in physiological and pathological conditions. Currently, a large number of studies have shown that H2S mediates apoptosis through multiple signaling pathways to participate in cancer occurrence and development, for example, PI3K/Akt/mTOR and MAPK signaling pathways. Therefore, the regulation of the production and metabolism of H2S to mediate the apoptotic process of cancer cells may improve the effectiveness of cancer treatment. In this review, the role and mechanism of H2S in cancer cell apoptosis in mammals are summarized.

Sulfur signaling pathway in cardiovascular disease

Hydrogen sulfide (H2S) and sulfur dioxide (SO2), recognized as endogenous sulfur-containing gas signaling molecules, were the third and fourth molecules to be identified subsequent to nitric oxide and carbon monoxide (CO), and exerted diverse biological effects on the cardiovascular system. However, the exact mechanisms underlying the actions of H2S and SO2 have remained elusive until now. Recently, novel post-translational modifications known as S-sulfhydration and S-sulfenylation, induced by H2S and SO2 respectively, have been proposed. These modifications involve the chemical alteration of specific cysteine residues in target proteins through S-sulfhydration and S-sulfenylation, respectively. H2S induced S-sulfhydrylation can have a significant impact on various cellular processes such as cell survival, apoptosis, cell proliferation, metabolism, mitochondrial function, endoplasmic reticulum stress, vasodilation, anti-inflammatory response and oxidative stress in the cardiovascular system. Alternatively, S-sulfenylation caused by SO2 serves primarily to maintain vascular homeostasis. Additional research is warranted to explore the physiological function of proteins with specific cysteine sites, despite the considerable advancements in comprehending the role of H2S-induced S-sulfhydration and SO2-induced S-sulfenylation in the cardiovascular system. The primary objective of this review is to present a comprehensive examination of the function and potential mechanism of S-sulfhydration and S-sulfenylation in the cardiovascular system. Proteins that undergo S-sulfhydration and S-sulfenylation may serve as promising targets for therapeutic intervention and drug development in the cardiovascular system. This could potentially expedite the future development and utilization of drugs related to H2S and SO2.