Novel GSK-3β Inhibitor Neopetroside A Protects Against Murine Myocardial Ischemia/Reperfusion Injury

The Role of Mitochondrial Permeability Transition in Bone Metabolism, Bone Healing, and Bone Diseases

Bone is a dynamic organ with an active metabolism and high sensitivity to mitochondrial dysfunction. The mitochondrial permeability transition pore (mPTP) is a low-selectivity channel situated in the inner mitochondrial membrane (IMM), permitting the exchange of molecules of up to 1.5 kDa in and out of the IMM. Recent studies have highlighted the critical role of the mPTP in bone tissue, but there is currently a lack of reviews concerning this topic. This review discusses the structure and function of the mPTP and its impact on bone-related cells and bone-related pathological states. The mPTP activity is reduced during the osteogenic differentiation of mesenchymal stem cells (MSCs), while its desensitisation may underlie the mechanism of enhanced resistance to apoptosis in neoplastic osteoblastic cells. mPTP over-opening triggers mitochondrial swelling, regulated cell death, and inflammatory response. In particular, mPTP over-opening is involved in dexamethasone-induced osteoblast dysfunction and bisphosphonate-induced osteoclast apoptosis. In vivo, the mPTP plays a significant role in maintaining bone homeostasis, with many bone disorders linked to its excessive opening. Genetic deletion or pharmacological inhibition of the over-opening of mPTP has shown potential in enhancing bone injury recovery and alleviating bone diseases. Here, we review the findings on the relationship of the mPTP and bone at both the cellular and disease levels, highlighting novel avenues for pharmacological approaches targeting mitochondrial function to promote bone healing and manage bone-related disorders.

Glycogen synthase kinase-3β: A multifaceted player in ischemia-reperfusion injury and its therapeutic prospects

Ischemia-reperfusion injury (IRI) results in irreversible metabolic dysfunction and structural damage to tissues or organs, posing a formidable challenge in the field of organ implantation, cardiothoracic surgery, and general surgery. Glycogen synthase kinase-3β (GSK-3β) a multifunctional serine/threonine kinase, is involved in a variety of biological processes, including cell proliferation, apoptosis, and immune response. Phosphorylation of its tyrosine 216 and serine 9 sites positively and negatively regulates the activation and inactivation of the enzyme. Significantly, inhibition or inactivation of GSK-3β provides protection against IRI, making it a viable target for drug development. Though numerous GSK-3β inhibitors have been identified to date, the development of therapeutic treatments remains a considerable distance away. In light of this, this review summarizes the complicated network of GSK-3β roles in IRI. First, we provide an overview of GSK-3β's basic background. Subsequently, we briefly review the pathological mechanisms of GSK-3β in accelerating IRI, and highlight the latest progress of GSK-3β in multiorgan IRI, encompassing heart, brain, kidney, liver, and intestine. Finally, we discuss the current development of GSK-3β inhibitors in various organ IRI, offering a thorough and insightful reference for GSK-3β as a potential target for future IRI therapy.

Inhibition of tartrate-resistant acid phosphatase 5 can prevent cardiac fibrosis after myocardial infarction

BACKGROUND

Myocardial infarction (MI) leads to enhanced activity of cardiac fibroblasts (CFs) and abnormal deposition of extracellular matrix proteins, resulting in cardiac fibrosis. Tartrate-resistant acid phosphatase 5 (ACP5) has been shown to promote cell proliferation and phenotypic transition. However, it remains unclear whether ACP5 is involved in the development of cardiac fibrosis after MI. The present study aimed to investigate the role of ACP5 in post-MI fibrosis and its potential underlying mechanisms.

METHODS

Clinical blood samples were collected to detect ACP5 concentration. Myocardial fibrosis was induced by ligation of the left anterior descending coronary artery. The ACP5 inhibitor, AubipyOMe, was administered by intraperitoneal injection. Cardiac function and morphological changes were observed on Day 28 after injury. Cardiac CFs from neonatal mice were extracted to elucidate the underlying mechanism in vitro. The expression of ACP5 was silenced by small interfering RNA (siRNA) and overexpressed by adeno-associated viruses to evaluate its effect on CF activation.

RESULTS

The expression of ACP5 was increased in patients with MI, mice with MI, and mice with Ang II-induced fibrosis in vitro. AubipyOMe inhibited cardiac fibrosis and improved cardiac function in mice after MI. ACP5 inhibition reduced cell proliferation, migration, and phenotypic changes in CFs in vitro, while adenovirus-mediated ACP5 overexpression had the opposite effect. Mechanistically, the classical profibrotic pathway of glycogen synthase kinase-3β (GSK3β)/β-catenin was changed with ACP5 modulation, which indicated that ACP5 had a positive regulatory effect. Furthermore, the inhibitory effect of ACP5 deficiency on the GSK3β/β-catenin pathway was counteracted by an ERK activator, which indicated that ACP5 regulated GSK3β activity through ERK-mediated phosphorylation, thereby affecting β-catenin degradation.

CONCLUSION

ACP5 may influence the proliferation, migration, and phenotypic transition of CFs, leading to the development of myocardial fibrosis after MI through modulating the ERK/GSK3β/β-catenin signaling pathway.

Epigallocatechin-3-gallate confers protection against myocardial ischemia/reperfusion injury by inhibiting ferroptosis, apoptosis, and autophagy via modulation of 14-3-3η

Previous studies have demonstrated that the underlying mechanisms of myocardial ischemia/reperfusion injury (MIRI) are complex and involve multiple types of regulatory cell death, including ferroptosis, apoptosis, and autophagy. Thus, we aimed to identify the mechanisms underlying MIRI and validate the protective role of epigallocatechin-3-gallate (EGCG) and its related mechanisms in MIRI. An in vivo and in vitro models of MIRI were constructed. The results showed that pretreatment with EGCG could attenuate MIRI, as indicated by increased cell viability, reduced lactate dehydrogenase (LDH) activity and apoptosis, inhibited iron overload, abnormal lipid metabolism, preserved mitochondrial function, decreased infarct size, maintained cardiac function, decreased reactive oxygen species (ROS) level, and reduced TUNEL-positive cells. Additionally, EGCG pretreatment could attenuate ferroptosis, apoptosis, and autophagy induced by MIRI via upregulating 14-3-3η protein levels. Furthermore, the protective effects of EGCG could be abolished with pAd/14-3-3η-shRNA or Compound C11 (a 14-3-3η inhibitor) but not pAd/NC-shRNA. In conclusion, EGCG pretreatment attenuated ferroptosis, apoptosis, and autophagy by mediating 14-3-3η and protected cardiomyocytes against MIRI.

Mitochondrial Kinase Signaling for Cardioprotection

Myocardial ischemia/reperfusion injury is reduced by cardioprotective adaptations such as local or remote ischemic conditioning. The cardioprotective stimuli activate signaling cascades, which converge on mitochondria and maintain the function of the organelles, which is critical for cell survival. The signaling cascades include not only extracellular molecules that activate sarcolemmal receptor-dependent or -independent protein kinases that signal at the plasma membrane or in the cytosol, but also involve kinases, which are located to or within mitochondria, phosphorylate mitochondrial target proteins, and thereby modify, e.g., respiration, the generation of reactive oxygen species, calcium handling, mitochondrial dynamics, mitophagy, or apoptosis. In the present review, we give a personal and opinionated overview of selected protein kinases, localized to/within myocardial mitochondria, and summarize the available data on their role in myocardial ischemia/reperfusion injury and protection from it. We highlight the regulation of mitochondrial function by these mitochondrial protein kinases.

WSB1, as an E3 ligase, restrains myocardial ischemia-reperfusion injury by activating β-catenin signaling via promoting GSK3β ubiquitination

BACKGROUND

Reperfusion is the most effective strategy for myocardial infarct, but induces additional injury. WD repeat and SOCS box containing protein 1 (WSB1) plays a protective role in ischemic cells. This study aims to investigate the effects of WSB1 on myocardial ischemia-reperfusion (IR) injury.

METHODS

The myocardial IR was induced by left anterior descending (LAD) ligation for 45 min and subsequent reperfusion. The overexpression of WSB1 was mediated by tail vein injection of AAV9 loaded with WSB1 encoding sequence two weeks before IR surgery. H9c2 myocardial cells underwent oxygen-sugar deprivation/reperfusion (OGD/R) to mimic IR, and transfected with WSB1 overexpression or silencing plasmid to alter the expression of WSB1.

RESULTS

WSB1 was found highly expressed in penumbra of myocardial IR rats, and the WSB1 overexpression relieved IR-induced cardio dysfunction, myocardial infarct and pathological damage, and cardiomyocyte death in penumbra. The ectopic expression of WSB1 in H9c2 myocardial cells mitigated OGD/R-caused apoptosis, and silencing of WSB1 exacerbated the apoptosis. In addition, WSB1 activated β-catenin signaling, which was deactivated under the ischemic condition. The co-immunoprecipitation results revealed that WSB1 mediated ubiquitination and degradation of glycogen synthase kinase 3 beta (GSK3β) as an E3 ligase in myocardial cells. The effects of WSB1 on myocardial cells under ischemic conditions were abolished by an inhibitor of β-catenin signaling.

CONCLUSION

WSB1 activated β-catenin pathway by promoting the ubiquitination of GSK3β, and restrained IR-induced myocardial injury. These findings might provide novel insights for clinical treatment of myocardial ischemic patients.

Neopetroside-B alleviates doxorubicin-induced cardiotoxicity via mitochondrial protection

Doxorubicin, a member of the anthracycline family, is a widely prescribed anticancer chemotherapy drug. Unfortunately, cumulative doses of doxorubicin can cause mitochondrial dysfunction, leading to acute or chronic cardiotoxicity. This study demonstrated that Neopetroside-B (NPS-B) protects cardiomyocytes in the presence of doxorubicin. NPS-B improved mitochondrial function in cardiomyocytes by increasing ATP production and oxygen consumption rates. On the other hand, NPS-B negatively influenced cancer cell lines by increasing reactive oxygen species. We analyzed NPS-B-influenced metabolites (VIP > 1.0; AUC>0.7; p < 0.05) and proteins (FC > 2.0) and constructed metabolite-protein enrichment, which showed that NPS-B affected uracil metabolism and NAD-binding proteins (e.g., aldehyde dehydrogenase and glutathione reductase) in cardiomyocytes. However, for the cancer cells, NPS-B decreased the NAD+/NADH balance, impairing cell viability. In a xenograft mouse model treated with doxorubicin, NPS-B reduced cardiac fibrosis and improved cardiac function. NPS-B may be a beneficial intervention to reducing doxorubicin-induced cardiotoxicity with anticancer effects.

Polyvinyl Alcohol (PVA)-Based Nanoniosome for Enhanced in vitro Delivery and Anticancer Activity of Thymol

Introduction

There is an unmet need to develop potent therapeutics against cancer with minimal side effects and systemic toxicity. Thymol (TH) is an herbal medicine with anti-cancer properties that has been investigated scientifically. This study shows that TH induces apoptosis in cancerous cell lines such as MCF-7, AGS, and HepG2. Furthermore, this study reveals that TH can be encapsulated in a Polyvinyl alcohol (PVA)-coated niosome (Nio-TH/PVA) to enhance its stability and enable its controlled release as a model drug in the cancerous region.

Materials and Methods

TH-loaded niosome (Nio-TH) was fabricated and optimized using Box-Behnken method and the size, polydispersity index (PDI) and entrapment efficiency (EE) were characterized by employing DLS, TEM and SEM, respectively. Additionally, in vitro drug release and kinetic studies were performed. Cytotoxicity, antiproliferative activity, and the mechanism were assessed by MTT assay, quantitative real-time PCR, flow cytometry, cell cycle, caspase activity evaluation, reactive oxygen species investigation, and cell migration assays.

Results

This study demonstrated the exceptional stability of Nio-TH/PVA at 4 °C for two months and its pH-dependent release profile. It also showed its high toxicity on cancerous cell lines and high compatibility with HFF cells. It revealed the modulation of Caspase-3/Caspase-9, MMP-2/MMP-9 and Cyclin D/ Cyclin E genes by Nio-TH/PVA on the studied cell lines. It confirmed the induction of apoptosis by Nio-TH/PVA in flow cytometry, caspase activity, ROS level, and DAPI staining assays. It also verified the inhibition of metastasis by Nio-TH/PVA in migration assays.

Conclusion

Overall, the results of this study revealed that Nio-TH/PVA may effectively transport hydrophobic drugs to cancer cells with a controlled-release profile to induce apoptosis while exhibiting no detectable side effects due to their biocompatibility with normal cells.