N-acetylcysteine attenuates systemic platelet activation and cerebral vessel thrombosis in diabetes

N-acetylcysteine Protects Against Myocardial Ischemia-Reperfusion Injury Through Anti-ferroptosis in Type 1 Diabetic Mice

The hearts of subjects with diabetes are vulnerable to ischemia-reperfusion injury (IRI). In contrast, experimentally rodent hearts have been shown to be more resistant to IRI at the very early stages of diabetes induction than the heart of the non-diabetic control mice, and the mechanism is largely unclear. Ferroptosis has recently been shown to play an important role in myocardial IRI including that in diabetes, while the specific mechanisms are still unclear. Non-diabetic control (NC) and streptozotocin-induced diabetic (DM) mice were treated with the antioxidant N-acetylcysteine (NAC) in drinking water for 4 week starting at 1 week after diabetes induction. Mice were subjected to myocardial IRI induced by occluding the coronary artery for 30 min followed by 2 h of reperfusion, subsequently at 1, 2, and 5 week of diabetes induction. The post-ischemic myocardial infarct size in the DM mice was smaller than that in NC mice at 1 week of diabetes but greater than that in the NC mice at 2 and 5 week of diabetes, which were associated with a significant increase of ferroptosis at 2 and 5 week but a significant reduction of ferroptosis at 1 week of diabetes. NAC significantly attenuated post-ischemic ferroptosis as well as oxidative stress and reduced infarct size at 2 and 5 week of diabetes. Application of erastin, a ferroptosis inducer, reversed the cardioprotective effects of NAC. It is concluded that increased oxidative stress and ferroptosis are the major factors attributable to the increased vulnerability to myocardial IRI in diabetes and that attenuation of ferroptosis represents a major mechanism whereby NAC confers cardioprotection against myocardial IRI in diabetes.

Homocysteine May Decrease Glucose Uptake and Alter the Akt/GSK3β/GLUT1 Signaling Pathway in Hippocampal Slices: Neuroprotective Effects of Rivastigmine and Ibuprofen

Homocysteine (Hcy) is a risk factor for neurodegenerative diseases, such as Alzheimer's Disease, and is related to cellular and tissue damage. In the present study, we verified the effect of Hcy on neurochemical parameters (redox homeostasis, neuronal excitability, glucose, and lactate levels) and the Serine/Threonine kinase B (Akt), Glucose synthase kinase-3β (GSK3β) and Glucose transporter 1 (GLUT1) signaling pathway in hippocampal slices, as well as the neuroprotective effects of ibuprofen and rivastigmine alone or in combination in such effects. Male Wistar rats (90 days old) were euthanized and the brains were dissected. The hippocampus slices were pre-treated for 30 min [saline medium or Hcy (30 µM)], then the other treatments were added to the medium for another 30 min [ibuprofen, rivastigmine, or ibuprofen + rivastigmine]. The dichlorofluorescein formed, nitrite and Na+, K+-ATPase activity was increased by Hcy at 30 µM. Ibuprofen reduced dichlorofluorescein formation and attenuated the effect of Hcy. The reduced glutathione content was reduced by Hcy. Treatments with ibuprofen and Hcy + ibuprofen increased reduced glutathione. Hcy at 30 µM caused a decrease in hippocampal glucose uptake and GLUT1 expression, and an increase in Glial Fibrillary Acidic Protein-protein expression. Phosphorylated GSK3β and Akt levels were reduced by Hcy (30 µM) and co-treatment with Hcy + rivastigmine + ibuprofen reversed these effects. Hcy toxicity on glucose metabolism can promote neurological damage. The combination of treatment with rivastigmine + ibuprofen attenuated such effects, probably by regulating the Akt/GSK3β/GLUT1 signaling pathway. Reversal of Hcy cellular damage by these compounds may be a potential neuroprotective strategy for brain damage.

Alterations in factors associated with diabetic retinopathy combined with thrombosis: A review

Diabetic retinopathy (DR) is one of the most common and serious microvascular complications of diabetes mellitus, the incidence of which has been increasing annually, and it is the main cause of vision loss in diabetic patients and a common cause of blindness. It is now found that thrombosis plays a crucial role in the disease progression in DR patients, and the final vision loss in DR may be related to the occurrence of thrombosis in the retinal vessels, which is dominated by abnormal endothelial cell function, together with platelet dysfunction, imbalance of coagulation and fibrinolytic function, and related alterations of inflammatory factors leading to the main cause of thrombotic disease in DR patients. In this review, we examine the role between DR and thrombosis and the association of each factor, including endothelial dysfunction; platelet dysfunction; coagulation-fibrinolytic imbalance; and alterations in inflammatory factors.

N-acetylcysteine reduces severity and mortality in COVID-19 patients: A systematic review and meta-analysis

Objectives

Recent clinical studies suggest that oxidative stress is one of the key players in the pathogenesis of coronavirus disease 2019 (COVID-19), and N-acetylcysteine (NAC), a potent antioxidant, has been shown to improve clinical outcomes in COVID-19 patients. We conducted a systematic review and meta-analysis of the literature published on the therapeutic intervention of NAC on COVID-19 infection.

Methods

We searched PubMed, Google Scholar, and Science Direct. We identified and screened eight studies with 20,503 participants, including 2,852 in the NAC-treated group and 17,651 in the placebo group, which reported the effect of NAC on COVID-19 infection. A meta-analysis was performed using forest plots under fixed effect estimates based on the standardized mean difference (SMD) and risk ratio (RR).

Results

Pooled analysis showed that NAC was associated with lower mortality in patients with COVID-19 compared with the placebo group [RR, 0.65; (95% CI: 0.56 to 0.75); p < 0.0001]. Similarly, C-reactive protein (CRP) [SMD, -0.32; (95% CI: -56 to -0.09); p = 0.0070] and D-dimer [SMD, -0.35, (95% CI: -0.59 to -0.10; p = 0.0062] levels were significantly decreased, and the oxygenation marker, PaO2/FiO2 ratio, was increased in the NAC-treated group compared with the placebo group [SMD, 0.76; (95% CI: 0.48 to 1.03); p < 0.0001].

Conclusion

Although the number of included studies was minimal, this meta-analysis suggests that NAC may have a positive effect on COVID-19 outcomes, specifically, a significant decrease in CRP and D-dimer levels and a significant increase in oxygen saturation, which decreased mortality. We have also presented a comprehensive review of the role and mechanisms of NAC in patients with COVID-19.

Increased reactive oxygen species lead to overactivation of platelets in essential thrombocythemia

INTRODUCTION

Platelet function, rather than platelet count, plays a crucial role in thrombosis in essential thrombocythemia (ET). However, little is known about the abnormal function of platelets in ET. Here, we investigated the functional characteristics of platelets in ET hemostasis to explore the causes of ET platelet dysfunction and new therapeutic strategies for ET.

MATERIALS AND METHODS

We analyzed platelet aggregation, activation, apoptosis, and reactive oxygen species (ROS) in ET patients and JAK2V617F-positive ET-like mice. The effects of ROS on platelet function and the underlying mechanism were investigated by inhibiting ROS using N-acetylcysteine (NAC).

RESULTS

Platelet aggregation, activation, apoptosis, ROS, and clot retraction were elevated in ET. No significant differences were observed between ET patients with JAK2V617F or CALR mutations. Increased ROS activated the JAK-STAT pathway, which may further influence platelet function. Inhibition of platelet ROS by NAC reduced platelet aggregation, activation, and apoptosis, and prolonged bleeding time. Furthermore, NAC treatment reduced platelet count in ET-like mice by inhibiting platelet production from megakaryocytes.

CONCLUSIONS

Elevated ROS in ET platelets resulted in enhanced platelet activation, function and increased risk of thrombosis. NAC offers a potential therapeutic strategy for reducing platelet count.

The Role of Oxidative Stress in Acute Ischemic Stroke-Related Thrombosis

Acute ischemic stroke is a serious life-threatening disease that affects almost 600 million people each year throughout the world with a mortality of more than 10%, while two-thirds of survivors remain disabled. However, the available treatments for ischemic stroke are still limited to thrombolysis and/or mechanical thrombectomy, and there is an urgent need for developing new therapeutic target. Recently, intravascular oxidative stress, derived from endothelial cells, platelets, and leukocytes, has been found to be tightly associated with stroke-related thrombosis. It not only promotes primary thrombus formation by damaging endothelial cells and platelets but also affects thrombus maturation and stability by modifying fibrin components. Thus, oxidative stress is expected to be a novel target for the prevention and treatment of ischemic stroke. In this review, we first discuss the mechanisms by which oxidative stress promotes stroke-related thrombosis, then summarize the oxidative stress biomarkers of stroke-related thrombosis, and finally put forward an antithrombotic therapy targeting oxidative stress in ischemic stroke.

Methylglyoxal in the Brain: From Glycolytic Metabolite to Signalling Molecule

Advances in molecular biology technology have piqued tremendous interest in glycometabolism and bioenergetics in homeostasis and neural development linked to ageing and age-related diseases. Methylglyoxal (MGO) is a by-product of glycolysis, and it can covalently modify proteins, nucleic acids, and lipids, leading to cell growth inhibition and, eventually, cell death. MGO can alter intracellular calcium homeostasis, which is a major cell-permeant precursor to advanced glycation end-products (AGEs). As side-products or signalling molecules, MGO is involved in several pathologies, including neurodevelopmental disorders, ageing, and neurodegenerative diseases. In this review, we demonstrate that MGO (the metabolic side-product of glycolysis), the GLO system, and their analogous relationship with behavioural phenotypes, epigenetics, ageing, pain, and CNS degeneration. Furthermore, we summarise several therapeutic approaches that target MGO and the glyoxalase (GLO) system in neurodegenerative diseases.

N-Acetylcysteine as Prophylactic Therapy for Transplantation-Associated Thrombotic Microangiopathy: A Randomized, Placebo-Controlled Trial

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a life-threatening complication for patients undergoing hematopoietic stem cell transplantation (HSCT). N-acetylcysteine (NAC) has recently been considered as a potential treatment for patients with thrombotic thrombocytopenic purpura. To assess the value of NAC for the prevention of TA-TMA, we conducted a prospective study at the First Affiliated Hospital of Soochow University. This open-label, randomized placebo-controlled trial included 160 patients who were scheduled for allogeneic HSCT. Participants were assigned at random 1:1 to either oral NAC (50 mg/kg/day from 9 days before HSCT to 30 days after HSCT) or placebo treatment. The primary outcome was the incidence of TA-TMA. Overall survival (OS) and event-free survival (EFS) were assessed in the NAC and placebo control groups. The incidence of TA-TMA was 9.1% (95% confidence interval [CI], 2% to 16.2%) in the NAC group, compared with 23% (95% CI, 13.2% to 32.8%) in the control group, with a rate ratio of .34 (95% CI, .123 to .911; P = .039). The median time to the onset of TA-TMA was 60 days (interquartile range [IQR], 42 to 129 days) in the NAC group and 36 days (IQR, 30.5 to 51 days) in the control group (P = .063). The 2-year OS rate was 75.4% (95% CI, 28.65% to 73.53%) in the NAC group and 63.0% (95% CI, 50.8% to 73.5%) in the control group, with a hazard ratio (HR) of .622 (95% CI, .334-1.155; P = .132). The EFS rate was 25.8% in the NAC patients and 8.1% in controls (HR, .254; 95% CI, .094 to .692; P = .024). The median time of EFS was 60 days in the NAC group and 38 days in controls. Our findings suggest that NAC may be a potential treatment to reduce the incidence of TA-TMA.

N-acetyl-L-cysteine ameliorates hepatocyte pyroptosis of dog type 1 diabetes mellitus via suppression of NLRP3/NF-κB pathway

Type 1 diabetes mellitus (T1DM) is a chronic and represented by insulin-causing pancreatic β-cell disruption and hyperglycemia. N-Acetyl-Cysteine (NAC) is regarded as facilitating endothelial cell function and angiogenesis and may have treatment effect in the case of diabetes. However, the impact of NAC on T1DM are unknown. Here we reported that inflammatory pathogenesis of canine type 1 diabetes liver disease and the therapeutic effect of NAC combined with insulin. For this purpose, the model was established by intravenous injection of streptozotocin (20 mg/kg). Forty adult dogs were used and divided into 5 groups: control group, DM group, insulin treatment group, NAC combined with insulin therapy, and NAC group, while study lasted for 16 weeks. Results showed that the level of liver function enzyme activity were apparently increased in DM group, while the NAC with insulin treatment remarkable decreased liver function enzyme levels. Histopathology revealed that obvious changes in liver structure of all DM group, as evidenced by hepatocyte disorder and cellular swelling. Liver structure was evaluated by Periodic Acid Schiff (PAS) and Masson staining, the tissues appeared glycogen deposition and collagen deposition, indicating that DM aggravated liver injury. Compared with control group, the protein and mRNA expression of NLRP3, Caspase-1, ASC, and GSDMD were significantly induced in the DM group, while INS and NAC combined with INS treatment reversed the above changes. The levels of NF-κB P65, p-NF-κB, and IFN γ were availably enhanced in the DM group, which decreased through insulin and NAC combined with insulin treatment. This study demonstrated that NAC combined with INS exerted protective effects against STZ-induced liver injury by inhibiting the NLRP3/NF-κB pathway. The findings indicated that NAC combined with INS may serve as a potential candidate therapy for the treatment of T1DM.

N-Acetylcysteine protects against cobalt chloride-induced endothelial dysfunction by enhancing glucose-6-phosphate dehydrogenase activity

Hypoxia‐induced endothelial dysfunction is known to be involved in the pathogenesis of several vascular diseases. However, it remains unclear whether the pentose phosphate pathway (PPP) is involved in regulating the response of endothelial cells to hypoxia. Here, we established an in vitro model by treating EA.hy926 (a hybrid human umbilical vein cell line) with cobalt chloride (CoCl₂; a chemical mimic that stabilizes HIF‐1α, thereby leading to the development of hypoxia), and used this to investigate the involvement of PPP by examining expression of its key enzyme, glucose‐6‐phosphate dehydrogenase (G6PD). We report that CoCl₂ induces the accumulation of HIF‐1α, leading to endothelial cell dysfunction characterized by reduced cell viability, proliferation, tube formation, and activation of cytokine production, accompanied with a significant decrease in G6PD expression and activity. The addition of 6‐aminonicotinamide (6‐AN) to inhibit PPP directly causes endothelial dysfunction. Additionally, N‐Acetylcysteine (NAC), a precursor of glutathione, was further evaluated for its protective effects; NAC displayed a protective effect against CoCl₂‐induced cell damage by enhancing G6PD activity, and this was abrogated by 6‐AN. The effects of CoCl₂ and the involvement of G6PD in endothelial dysfunction have been confirmed in primary human aortic endothelial cells. In summary, G6PD was identified as a novel target of CoCl₂‐induced damage, which highlighted the involvement of PPP in regulating the response of endothelial cell CoCl₂. Treatment with NAC may be a potential strategy to treat hypoxia or ischemia, which are widely observed in vascular diseases.

Redox signaling at the crossroads of human health and disease

Redox biology is at the core of life sciences, accompanied by the close correlation of redox processes with biological activities. Redox homeostasis is a prerequisite for human health, in which the physiological levels of nonradical reactive oxygen species (ROS) function as the primary second messengers to modulate physiological redox signaling by orchestrating multiple redox sensors. However, excessive ROS accumulation, termed oxidative stress (OS), leads to biomolecule damage and subsequent occurrence of various diseases such as type 2 diabetes, atherosclerosis, and cancer. Herein, starting with the evolution of redox biology, we reveal the roles of ROS as multifaceted physiological modulators to mediate redox signaling and sustain redox homeostasis. In addition, we also emphasize the detailed OS mechanisms involved in the initiation and development of several important diseases. ROS as a double-edged sword in disease progression suggest two different therapeutic strategies to treat redox-relevant diseases, in which targeting ROS sources and redox-related effectors to manipulate redox homeostasis will largely promote precision medicine. Therefore, a comprehensive understanding of the redox signaling networks under physiological and pathological conditions will facilitate the development of redox medicine and benefit patients with redox-relevant diseases.

COVID-19 Medical and Pharmacological Management in the European Countries Compared to Italy: An Overview

(1) Background: Italy accounts for more than 150,000 deaths due to the COVID-19 pandemic, leading the top rank in SARS-CoV-2-caused deceases in Europe. A survey on the different ways by which the COVID-19 pandemic emergency was managed in the foreign European countries compared to Italy is the purpose of this paper. (2) Methods: A literature search and various mathematical algorithms to approach a rank scoring scale were used to describe in detail the different approaches used by European countries to manage the COVID-19 pandemic emergency. (3) Results: The study showed that Italy stands at the bottom ranking for COVID-19 management due to its high mortality rate. Possible causes of the observed huge numbers of hospitalization and deaths were (a) the demographic composition of the European country; (b) its decentralized healthcare system organization; (c) the role of correct pharmacology in the early stages before hospitalization. Post-mortem examinations were of paramount importance to elucidate the etiopathogenesis of COVID-19 and to tailor a suitable and proper therapy in the early symptomatic stages of COVID-19, preventing hospitalization. (4) Conclusions: Factors such as the significant impact on elderly people, the public health organization prevalently state-owned and represented mainly by hospitals, and criticism of the home therapy approach toward SARS-CoV-2-infected people, may have concurred in increasing the number of COVID-19 deaths in Italy.

N-Acetylcysteine Inhibits Platelet Function through the Regeneration of the Non-Oxidative Form of Albumin

N-acetylcysteine (NAC) is able to break down protein disulfides, generating free thiols. This mechanism occurs on mixed disulfides of albumin (HSA) to form mercaptoalbumin (HMA), the main antioxidant species in the plasma. Circulating HSA exists in two main forms: the reduced form (HMA), and the oxidized forms, whose predominant modification is cystenylation (HSA-Cys). Increased levels of oxidized HSA have been detected in several diseases associated with oxidative stress. This study showed that NAC inhibits platelet aggregation by restoring HMA. In addition, the regeneration of HMA by NAC inhibits platelet functions such as intracellular calcium mobilization, reactive oxygen species generation, arachidonic acid metabolites synthesis, and adhesion to the collagen matrix. In our conditions, the exposure of platelets to NAC did not increase GSH levels. However, the inhibition of platelet aggregation was also detected following treatment of platelet-rich plasma with GSH, which, similarly to NAC, reduced HSA-Cys levels. Furthermore, this study showed that cysteine, another compound able to restore HMA by reducing the HSA-Cys content, inhibited platelet aggregation to a similar extent as NAC. The results obtained in this study suggest a new mechanism by which NAC can modulate platelet activation and suggest its possible use as an antiplatelet drug in conditions associated with oxidative stress.

N-Acetylcysteine and Hydrogen Sulfide in Coronavirus Disease 2019

Significance: Hydrogen sulfide (H₂S) is one of the three main gasotransmitters that are endogenously produced in humans and are protective against oxidative stress. Recent findings from studies focusing on coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), shifted our attention to a potentially modulatory role of H₂S in this viral respiratory disease. Recent Advances: H₂S levels at hospital admission may be of importance since this gasotransmitter has been shown to be protective against lung damage through its antiviral, antioxidant, and anti-inflammatory actions. Furthermore, many COVID-19 cases have been described demonstrating remarkable clinical improvement upon administration of high doses of N-acetylcysteine (NAC). NAC is a renowned pharmacological antioxidant substance acting as a source of cysteine, thereby promoting endogenous glutathione (GSH) biosynthesis as well as generation of sulfane sulfur species when desulfurated to H₂S. Critical Issues: Combining H₂S physiology and currently available knowledge of COVID-19, H₂S is hypothesized to target three main vulnerabilities of SARS-CoV-2: (i) cell entry through interfering with functional host receptors, (ii) viral replication through acting on RNA-dependent RNA polymerase (RdRp), and (iii) the escalation of inflammation to a potentially lethal hyperinflammatory cytokine storm (toll-like receptor 4 [TLR4] pathway and NLR family pyrin domain containing 3 [NLRP3] inflammasome). Future Directions: Dissecting the breakdown of NAC reveals the possibility of increasing endogenous H₂S levels, which may provide a convenient rationale for the application of H₂S-targeted therapeutics. Further randomized-controlled trials are warranted to investigate its definitive role.

Understanding the Activation of Platelets in Diabetes and Its Modulation by Allyl Methyl Sulfide, an Active Metabolite of Garlic

BACKGROUND

Diabetes mellitus (DM) is a chronic metabolic disorder associated with higher risk of having cardiovascular disease. Platelets play a promising role in the pathogenesis of cardiovascular complications in diabetes. Since last several decades, garlic and its bioactive components are extensively studied in diabetes and its complications. Our aim was to explore the antiplatelet property of allyl methyl sulfide (AMS) focusing on ameliorating platelet activation in diabetes.

METHOD

We used streptozotocin- (STZ-) induced diabetic rats as model for type 1 diabetes. We have evaluated the effect of allyl methyl sulfide on platelet activation by administrating AMS to diabetic rats for 10 weeks. Flow cytometry-based analysis was used to evaluate the platelet activation, platelet aggregation, platelet macrophage interaction, and endogenous ROS generation in the platelets obtained from control, diabetes, and AMS- and aspirin-treated diabetic rats.

RESULTS

AMS treatment for 10 weeks effectively reduced the blood glucose levels in diabetic rats. Three weeks of AMS (50 mg/kg/day) treatment did not reduce the activation of platelets but a significant (p < 0.05) decrease was observed after 10 weeks of treatment. Oral administration of AMS significantly (p < 0.05) reduced the baseline and also reduced ADP-induced aggregation of platelets after 3 and 10 weeks of treatment. Furthermore, 10 weeks of AMS treatment in diabetic rats attenuated the endogenous ROS content (p < 0.05) of platelets and platelet macrophage interactions. The inhibition of platelet activation in diabetic rats after AMS treatment was comparable with aspirin treatment (30 mg/kg/day).

CONCLUSION

We observed an inhibitory effect of allyl methyl sulfide on platelet aggregation, platelet activation, platelet macrophage interaction, and increased ROS levels in type 1 diabetes. Our data suggests that AMS can be useful to control cardiovascular complication in diabetes via inhibition of platelet activation.

Use of Thiols in the Treatment of COVID-19: Current Evidence

There is a possible role for oxidative stress, a state characterized by an altered balance between the production of free radicals or reactive oxygen species (ROS) and antioxidant defences, in coronavirus disease 2019 (COVID-19), the genesis of which is quite complex. Excessive oxidative stress could be responsible for the alveolar damage, thrombosis, and red blood cell dysregulation observed in COVID-19. Apparently, deficiency of glutathione (GSH), a low-molecular-weight thiol that is the most important non-enzymatic antioxidant molecule and has the potential to keep the cytokine storm in check, is a plausible explanation for the severe manifestations and death in COVID-19 patients. Thiol drugs, which are considered mucolytic, also possess potent antioxidant and anti-inflammatory properties. They exhibit antibacterial activity against a variety of medically important bacteria and may be an effective strategy against influenza virus infection. The importance of oxidative stress during COVID-19 and the various pharmacological characteristics of thiol-based drugs suggest a possible role of thiols in the treatment of COVID-19. Oral and intravenous GSH, as well as GSH precursors such as N-acetylcysteine (NAC), or drugs containing the thiol moiety (erdosteine) may represent a novel therapeutic approach to block NF-kB and address the cytokine storm syndrome and respiratory distress observed in COVID-19 pneumonia patients

Three-dimensional remodeling of functional cerebrovascular architecture and gliovascular unit in leptin receptor-deficient mice

The cerebrovascular sequelae of diabetes render victims more susceptible to ischemic stroke, vascular cognitive impairment, and Alzheimer's disease. However, limited knowledge exists on the progressive changes in cerebrovascular structure and functional remodeling in type 2 diabetes. To ascertain the impact of diabetes on whole-brain cerebrovascular perfusion, leptin-receptor-deficient mice were transcardially injected with tomato-lectin before sacrifice. The whole brain was clarified by the Fast free-of-acrylamide clearing tissue technique. Functional vascular anatomy of the cerebrum was visualized by light-sheet microscopy, followed by analysis in Imaris software. We observed enhanced neovascularization in adult db/db mice, characterized by increased branch level and loop structures. Microvascular hypoperfusion was initially detected in juvenile db/db mice, suggesting early onset of insufficient microcirculation. Furthermore, gliovascular unit remodeling was verified by loss of pericytes and overactivation of microglia and astrocytes in adult diabetic mice. However, the integrity of the blood-brain barrier (BBB) was fundamentally preserved, as shown by a lack of extravasation of IgG into the brain parenchyma. In summary, we, for the first time, reveal that functional cerebrovascular remodeling occurs as early as four weeks in db/db mice and the deficit in gliovascular coupling may play a role in cerebral hypoperfusion before BBB breakdown in 16-week-old db/db mice.

Glucose metabolic crosstalk and regulation in brain function and diseases

Brain glucose metabolism, including glycolysis, the pentose phosphate pathway, and glycogen turnover, produces ATP for energetic support and provides the precursors for the synthesis of biological macromolecules. Although glucose metabolism in neurons and astrocytes has been extensively studied, the glucose metabolism of microglia and oligodendrocytes, and their interactions with neurons and astrocytes, remain critical to understand brain function. Brain regions with heterogeneous cell composition and cell-type-specific profiles of glucose metabolism suggest that metabolic networks within the brain are complex. Signal transduction proteins including those in the Wnt, GSK-3β, PI3K-AKT, and AMPK pathways are involved in regulating these networks. Additionally, glycolytic enzymes and metabolites, such as hexokinase 2, acetyl-CoA, and enolase 2, are implicated in the modulation of cellular function, microglial activation, glycation, and acetylation of biomolecules. Given these extensive networks, glucose metabolism dysfunction in the whole brain or specific cell types is strongly associated with neurologic pathology including ischemic brain injury and neurodegenerative disorders. This review characterizes the glucose metabolism networks of the brain based on molecular signaling and cellular and regional interactions, and elucidates glucose metabolism-based mechanisms of neurological diseases and therapeutic approaches that may ameliorate metabolic abnormalities in those diseases.

N-acetylcysteine inhibits thrombosis in a murine model of myeloproliferative neoplasm

Thrombosis is a major cause of mortality in patients with myeloproliferative neoplasms (MPNs), though there is currently little to offer patients with MPN beyond aspirin and cytoreductive therapies such as hydroxyurea for primary prevention. Thrombogenesis in MPN involves multiple cellular mechanisms, including platelet activation and neutrophil-extracellular trap formation; therefore, an antithrombotic agent that targets one or more of these processes would be of therapeutic benefit in MPN. Here, we treated the JAK2V617F knockin mouse model of polycythemia vera with N-acetylcysteine (NAC), a sulfhydryl-containing compound with broad effects on glutathione replenishment, free radical scavenging, and reducing disulfide bonds, to investigate its antithrombotic effects in the context of MPN. Strikingly, NAC treatment extended the lifespan of JAK2V617F mice without impacting blood counts or splenomegaly. Using an acute pulmonary thrombosis model in vivo, we found that NAC reduced thrombus formation to a similar extent as the irreversible platelet inhibitor aspirin. In vitro analysis of platelet activation revealed that NAC reduced thrombin-induced platelet-leukocyte aggregate formation in JAK2V617F mice. Furthermore, NAC reduced neutrophil extracellular trap formation in primary human neutrophils from patients with MPN as well as healthy controls. These results provide evidence that N-acetylcysteine inhibits thrombosis in JAK2V617F mice and provide a pre-clinical rationale for investigating NAC as a therapeutic to reduce thrombotic risk in MPN.

N‑acetylcysteine inhibits atherosclerosis by correcting glutathione‑dependent methylglyoxal elimination and dicarbonyl/oxidative stress in the aorta of diabetic mice

In diabetic animal models, high plasma/tissue levels of methylglyoxal (MG) are implicated in atherosclerosis. N-acetylcysteine (NAC) is a cysteine prodrug that replenishes intracellular glutathione (GSH) levels, which can increase the elimination of MG in diabetes mellitus (DM). The present study investigated the anti-atherosclerotic role of NAC in DM and aimed to determine whether the mechanism involved GSH-dependent MG elimination in the aorta. Apolipoprotein-E knockdown (ApoE^−/−) mice injected with streptozotocin for 5 days exhibited enhanced atherosclerotic plaque size in the aortic root; notably, a high-lipid diet aggravated this alteration. NAC treatment in the drinking water for 12 weeks decreased the size of the atherosclerotic lesion, which was associated with a reduction in MG-dicarbonyl stress and oxidative stress, as indicated by decreased serum malondialdehyde levels, and increased superoxide dismutase-1 and glutathione peroxidase-1 levels in the diabetic aorta. Endothelial damage was also corrected by NAC, as indicated by an increase in the expression levels of phosphorylated (p-)Akt and p-endothelial nitric oxide synthase (eNOS) in the aorta, as well as nitric oxide (NO) in the serum. In addition, MG-treated human umbilical vein endothelial cells (HUVECs) exhibited increased reactive oxygen species and decreased antioxidant enzyme expression levels. NAC treatment corrected the alteration in HUVECs induced by MG, whereas the protective role of NAC was blocked via inhibition of GSH. These findings indicated that the diabetic aorta was more susceptible to atherosclerotic lesions compared with non-diabetic ApoE^−/− mice. Furthermore, NAC may offer protection against atherosclerotic development in DM by altering aortic and systemic responses via correcting GSH-dependent MG elimination, leading to decreased oxidative stress and restoration of the p-Akt/p-eNOS pathway in the aorta.

Preventing the development of severe COVID-19 by modifying immunothrombosis

BACKGROUND

COVID-19-associated acute respiratory distress syndrome (ARDS) is associated with significant morbidity and high levels of mortality. This paper describes the processes involved in the pathophysiology of COVID-19 from the initial infection and subsequent destruction of type II alveolar epithelial cells by SARS-CoV-2 and culminating in the development of ARDS.

MAIN BODY

The activation of alveolar cells and alveolar macrophages leads to the release of large quantities of proinflammatory cytokines and chemokines and their translocation into the pulmonary vasculature. The presence of these inflammatory mediators in the vascular compartment leads to the activation of vascular endothelial cells platelets and neutrophils and the subsequent formation of platelet neutrophil complexes. These complexes in concert with activated endothelial cells interact to create a state of immunothrombosis. The consequence of immunothrombosis include hypercoagulation, accelerating inflammation, fibrin deposition, migration of neutrophil extracellular traps (NETs) producing neutrophils into the alveolar apace, activation of the NLRP3 inflammazome, increased alveolar macrophage destruction and massive tissue damage by pyroptosis and necroptosis Therapeutic combinations aimed at ameliorating immunothrombosis and preventing the development of severe COVID-19 are discussed in detail.

PTEN inhibition attenuates endothelial cell apoptosis in coronary heart disease via modulating the AMPK-CREB-Mfn2-mitophagy signaling pathway

Atherosclerosis (AS) is a major pathogenic factor in patients with cardiovascular diseases, and endothelial dysfunction (ED) plays a primary role in the occurrence and development of AS. In our study, we attempted to evaluate the role of phosphatase and tensin homolog (PTEN) in endothelial cell apoptosis under oxidized low-density lipoprotein (ox-LDL) stimulation and identify the associated mechanisms. The results of our study demonstrated that ox-LDL induced human umbilical vein endothelial cell (HUVEC) death via mitochondrial apoptosis, as evidenced by reduced mitochondrial potential, increased mitochondria permeability transition pore opening, cellular calcium overload, and caspase-9/-3 activation. In addition, ox-LDL also suppressed cellular energy production via downregulating the mitochondrial respiratory complex. Moreover, ox-LDL impaired HUVECs migration. Western blot analysis showed that PTEN expression was upregulated after exposure to ox-LDL and knockdown of PTEN could attenuate ox-LDL-mediated endothelial cell damage. Furthermore, we found that ox-LDL impaired mitophagy activity, whereas PTEN deletion could improve mitophagic flux and this effect relied on the activity of the AMP-activated protein kinase (AMPK)-cAMP-response element-binding protein (CREB)-Mitofusin-2 (Mfn2) axis. When the AMPK-CREB-Mfn2 pathway was inhibited, PTEN deletion-associated HUVECs protection was significantly reduced, suggesting that the AMPK-CREB-Mfn2-mitophagy axis is required for PTEN deletion-mediated endothelial cell survival under ox-LDL. Taken together, our results indicate that ox-LDL-induced endothelial cell damage is associated with PTEN overexpression, and inhibition of PTEN could promote endothelial survival via activating the AMPK-CREB-Mfn2-mitophagy signaling pathway.

Spliced X-box binding protein 1 induces liver cancer cell death via activating the Mst1-JNK-mROS signalling pathway

Previous studies have found that the primary pathogenesis of liver cancer progression is linked to excessive cancer cell proliferation and rapid metastasis. Although therapeutic advances have been made for the treatment of liver cancer, the mechanism underlying the liver cancer progression has not been fully addressed. In the present study, we explored the role of spliced X-box binding protein 1 (XBP1) in regulating the viability and death of liver cancer cells in vitro. Our study demonstrated that XBP1 was upregulated in liver cancer cells when compared to the primary hepatocytes. Interestingly, the deletion of XBP1 could reduce the viability of liver cancer cells in vitro via inducing apoptotic response. Further, we found that XBP1 downregulation was also linked to proliferation arrest and migration inhibition. At the molecular levels, XBP1 inhibition is followed by activation of the Mst1 pathway which promoted the phosphorylation of c-Jun N-terminal kinase (JNK). Then, the active Mst1-JNK pathway mediated mitochondrial reactive oxygen species (mROS) overproduction and then excessive ROS induced cancer cell death. Therefore, our study demonstrated a novel role played by XBP1 in modulating the viability of liver cancer cells via the Mst1-JNK-mROS pathways.

Reactive Oxygen Species in Venous Thrombosis

Reactive oxygen species (ROS) have physiological roles as second messengers, but can also exert detrimental modifications on DNA, proteins and lipids if resulting from enhanced generation or reduced antioxidant defense (oxidative stress). Venous thrombus (DVT) formation and resolution are influenced by ROS through modulation of the coagulation, fibrinolysis, proteolysis and the complement system, as well as the regulation of effector cells such as platelets, endothelial cells, erythrocytes, neutrophils, mast cells, monocytes and fibroblasts. Many conditions that carry an elevated risk of venous thrombosis, such as the Antiphospholipid Syndrome, have alterations in their redox homeostasis. Dietary and pharmacological antioxidants can modulate several important processes involved in DVT formation, but their overall effect is unknown and there are no recommendations regarding their use. The development of novel antioxidant treatments that aim to abrogate the formation of DVT or promote its resolution will depend on the identification of targets that enable ROS modulation confined to their site of interest in order to prevent off-target effects on physiological redox mechanisms. Subgroups of patients with increased systemic oxidative stress might benefit from unspecific antioxidant treatment, but more clinical studies are needed to bring clarity to this issue.

Macrophage stimulating 1-induced inflammation response promotes aortic aneurysm formation through triggering endothelial cells death and activating the NF-κB signaling pathway

Aortic aneurysm formation is associated with endothelial cells dysfunction through an undefined mechanism. Macrophage stimulating 1 (Mst1) and NF-κB signaling pathway have been found to be related to inflammation response in endothelial cell damage. The goal of our study is to explore the role of Mst1 in regulating endothelial cell viability with a focus on NF-κB signaling pathway and inflammation response. Endothelial cell viability and death were determined via immunofluorescence and ELISA. Agonist of NF-κB signaling pathway and siRNA against Mst1 were used. The results in our study demonstrated that Mst1 transcription and expression were significantly elevated after exposure to oxidative stress in endothelial cells. Once loss of Mst1 through transfection of siRNA (si-Mst1), endothelial cell viability and survival rate were rapidly increased in response to oxidative stress. In addition, we also found that Mst1 controlled inflammation response and mitochondrial function in endothelial cells. Re-activation of NF-κB signaling pathway was followed by an activation of inflammation response and mitochondrial dysfunction, as evidenced by increased expression of inflammation factors and decreased ATP synthesis. Altogether, our results identify Mst1 as the primary factors responsible for endothelial cells dysfunction in aneurysms formation through inducing inflammation response, endothelial apoptosis, and NF-κB signaling pathway activation.

Irisin activates Opa1-induced mitophagy to protect cardiomyocytes against apoptosis following myocardial infarction

Myocardial infarction is characterized by sudden ischemia and cardiomyocyte death. Mitochondria have critical roles in regulating cardiomyocyte viability and can sustain damage under ischemic conditions. Mitophagy is a mechanism by which damaged mitochondria are removed by autophagy to maintain mitochondrial structure and function. We investigated the role of the dynamin-like GTPase optic atrophy 1 (Opa1) in mitophagy following myocardial infarction. Opa1 expression was downregulated in infarcted hearts in vivo and in hypoxia-treated cardiomyocytes in vitro. We found that Opa1 overexpression protected cardiomyocytes against hypoxia-induced damage and enhanced cell viability by inducing mitophagy. Opa1-induced mitophagy was activated by treatment with irisin, which protected cardiomyocytes from further damage following myocardial infarction. Opa1 knockdown abolished the cardioprotective effects of irisin resulting in an enhanced inflammatory response, increased oxidative stress, and mitochondrial dysfunction in cardiomyocytes. Our data indicate that Opa1 plays an important role in maintaining cardiomyocyte viability and mitochondrial function following myocardial infarction by inducing mitophagy. Irisin can activate Opa1-induced mitophagy and protect against cardiomyocyte injury following myocardial infarction.

The Usage of Lasso, Ridge, and Linear Regression to Explore the Most Influential Metabolic Variables that Affect Fasting Blood Sugar in Type 2 Diabetes Patients

Background and aims: To explore the most influential variables of fasting blood sugar (FBS) with three regression methods, to identify the existence chance of type 2 diabetes based on influential variables with logistic regression (LR), and to compare the three regression methods according to Mean Squared Error (MSE) value.

Material and Methods: In this cross-sectional study, 270 patients suffering from type 2 diabetes for at least 6 months and 380 healthy people were participated. The Linear regression, Ridge regression, and Least Absolute Shrinkage and Selection Operator (Lasso) regression were used to find influential variables for FBS.

Results: Among 15 variables (8 metabolic, 7 characteristic), Lasso regression selected HbA1c, Urea, age, BMI, heredity, and gender, Ridge regression selected HbA1c, heredity, gender, smoking status, and drug use, and Linear regression selected HbA1c as the most effective predictors for FBS.

Conclusion: HbA1c is the most influential predictor of FBS among 15 variables according to the result of three regression methods. Controlling the variation of HbA1c leads to a more stable FBS. Beside FBS that should be checked before breakfast, maybe HbA1c could be helpful in diagnosis of Type 2 diabetes.

Liraglutide reduces hyperglycemia-induced cardiomyocyte death through activating glucagon-like peptide 1 receptor and targeting AMPK pathway

Objective: Hyperglycemia-mediated cardiomyocyte damage is associated with inflammation and AMPK inactivation.Aim: The aim of our study is to explore the protective effects exerted by liraglutide on AMPK pathway and glucagon-like peptide 1 receptor in diabetic cardiomyopathy.Methods: Cardiomyocytes were treated with high-glucose stress and cardiomyocyte viability was determined via (3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide assay. Besides, LDH release, immunofluorescence, and qPCR were used to verify the influence of liraglutide on hyperglycemia-treated cardiomyocytes.Results: Hyperglycemia treatment caused inflammation response and oxidative stress were significantly elevated in cardiomyocytes. This alteration could be reversed by liraglutide. Besides, cell viability was reduced whereas apoptosis was increased after exposure to high glucose treatment. However, liraglutide treatment could attenuate apoptosis and reverse cell viability in cardiomyocyte. Further, we found that AMPK pathway was also activated and glucagon-like peptide 1 receptor expression was increased in response to liraglutide treatment.Conclusions: Liraglutide could attenuate hyperglycemia-mediated cardiomyocyte damage through reversing AMPK pathway and upregulating glucagon-like peptide 1 receptor.

Mief1 augments thyroid cell dysfunction and apoptosis through inhibiting AMPK-PTEN signaling pathway

Objective: Inflammation-mediated thyroid cell dysfunction and apoptosis increases the like-hood of hypothyroidism.Aim: Our aim in the present study is to explore the role of mitochondrial elongation factor 1 (Mief1) in thyroid cell dysfunction induced by TNFα.Materials and methods: Different doses of TNFα were used to incubate with thyroid cells in vitro. The survival rate, apoptotic index and proliferation capacity of thyroid cells were measured. Cellular energy metabolism and endoplasmic reticulum function related to protein synthesis were detected.Results: In response to TNFα treatment, the levels of Mief1 were increased, coinciding with a drop in the viability of thyroid cells in vitro. Loss of Mief1 attenuates TNFα-induced cell death through reducing the ratio of cell apoptosis. Further, we found that Mief1 deletion reversed cell energy metabolism and this effect was attributable to mitochondrial protection. Mief1 knockdown sustained mitochondrial membrane potential and reduced mitochondrial ROS overproduction. In addition, Mief1 knockdown also reduced endoplasmic reticulum stress, as evidenced by decreased levels of Chop and Caspase-12. Finally, our data verified that TNFα treatment inhibited the activity of AMPK-PTEN pathway whereas Mief1 deletion reversed the activity of AMPK and thus promoted the upregulation of PTEN. However, inhibition of AMPK-PTEN pathways could abolish the beneficial effects exerted by Mief1 deletion on thyroid cells damage and dysfunction.Conclusions: Altogether, our data indicate that immune abnormality-mediated thyroid cell dysfunction and death are alleviated by Mief1 deletion possible driven through reversing the activity of AMPK-PTEN pathways.

Evidence for a Beneficial Effect of Oral N-acetylcysteine on Functional Outcomes and Inflammatory Biomarkers in Patients with Acute Ischemic Stroke

PURPOSE

Numerous preclinical studies have demonstrated the potential neuroprotective effects of N-acetylcysteine (NAC) in the treatment of brain ischemia. Accordingly, the present study aimed to assess the potential therapeutic effects of oral NAC in patients with acute ischemic stroke.

PATIENTS AND METHODS

In a randomized, double-blind, placebo-controlled trial study, 68 patients with acute ischemic stroke with the onset of symptoms less than 24 hours were randomly assigned to either the NAC-treated group or placebo-treated group. NAC and matched placebo were administrated by a 72-hour oral protocol (initially 4 grams loading dose and after on, 4 g in 4 equal divided doses for more 2 days). The primary outcomes were quantification of any neurologic deficit by the use of the National Institute of Health Stroke Scale (NIHSS) score and functional disability by the use of the modified Rankin scale (mRS) at 90 days after stroke. Additionally, serum levels of markers of oxidative stress and inflammation as a main mechanism of its action were assessed at baseline and the end of 3-day treatment protocol.

RESULTS

NAC-treated patients in comparison with placebo-treated patients showed a significantly lower mean NIHSS scores at day 90 after stroke. A favorable functional outcome which was defined as an mRS score of 0 or 1, also in favor of NAC compared to placebo was noted on day 90 after stroke (57.6% in the NAC-treated group compared with 28.6% in the placebo-treated group). Further, compared to the placebo, NAC treatment significantly decreased serum levels of proinflammatory biomarkers such as interleukin 6 (IL-6), soluble intercellular cell adhesion molecule-1 (sICAM-1), nitric oxide (NO), malondialdehyde (MDA), and neuron-specific enolase (NSE) and significantly increased serum levels of anti-oxidant biomarkers such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and total thiol groups (TTG).

CONCLUSION

The pattern of results suggests that oral NAC administration early after an acute ischemic stroke is associated with a better outcome profile in terms of acute neurological deficit and disability grade compared to placebo. NAC may improve neurological outcomes of patients with stroke at least in part by its antioxidant and anti-inflammatory effects.

Evidence Supporting a Phased Immuno-physiological Approach to COVID-19 From Prevention Through Recovery

This paper presents an evidence-based strategy for improving clinical outcomes in COVID-19. Recommendations are based on the phases of the disease, because optimal interventions for one phase may not be appropriate for a different phase. The four phases addressed are: Prevention, Infection, Inflammation and Recovery. Underlying this phased approach is recognition of emerging evidence for two different components of pathophysiology, early infection and late stage severe complications. These two aspects of the disease suggest two different patterns of clinical emphasis that seem on the surface to be not entirely concordant. We describe the application of therapeutic strategies and appropriate tactics that address four main stages of disease progression for COVID-19. Emerging evidence in COVID-19 suggests that the SARS-CoV-2 virus may both evade the innate immune response and kill macrophages. Delayed innate immune response and a depleted population of macrophages can theoretically result in a blunted antigen presentation, delaying and diminishing activation of the adaptive immune response. Thus, one clinical strategy involves supporting patient innate and adaptive immune responses early in the time course of illness, with the goal of improving the timeliness, readiness, and robustness of both the innate and adaptive immune responses. At the other end of the disease pathology spectrum, risk of fatality in COVID-19 is driven by excessive and persistent upregulation of inflammatory mechanisms associated with cytokine storm. Thus, the second clinical strategy is to prevent or mitigate excessive inflammatory response to prevent the cytokine storm associated with high mortality risk. Clinical support for immune system pathogen clearance mechanisms involves obligate activation of immune response components that are inherently inflammatory. This puts the goals of the first clinical strategy (immune activation) potentially at odds with the goals of the second strategy(mitigation of proinflammatory effects). This creates a need for discernment about the time course of the illness and with that, understanding of which components of an overall strategy to apply at each phase of the time course of the illness. We review evidence from early observational studies and the existing literature on both outcomes and mechanisms of disease, to inform a phased approach to support the patient at risk for infection, with infection, with escalating inflammation during infection, and at risk of negative sequelae as they move into recovery.

Modulators of platelet function in aging

Platelets are small, anucleated effector cells that play an important role in linking the hemostatic and inflammatory processes in the body. Platelet function is known to be altered under various inflammatory conditions including aging. A gain in platelet function during aging can increase the risk of thrombotic events, such as stroke and acute myocardial infarction. Anti-platelet therapy is designed to reduce risk of serious cerebrovascular and cardiovascular events, but the adverse consequences of therapy, such as risk for bleeding increases with aging as well. Age-associated comorbidities such as obesity, diabetes, and hyperlipidemia also contribute to increased platelet activity and thus can enhance the risk of thrombosis. Therefore, identification of unique mechanisms of platelet dysfunction in aging and in age-associated comorbidities is warranted to design novel antiplatelet drugs. This review outlines some of the current areas of research on aging-related mechanisms of platelet hyperactivity and addresses the clinical urgency for designing anti-platelet therapies toward novel molecular targets in the aging population.

In vitro mitochondrial-targeted antioxidant peptide induces apoptosis in cancer cells

Introduction

Reactive oxygen species (ROS) are major contributors to cancer and involved in numerous tumor proliferation signaling pathways. Mitochondria are the major ROS-producing organelles, and ROS are produced from the synthesis of adenosine triphosphate and cell metabolism.

Methods

A novel mitochondria-targeted peptide, namely KRSH, was synthesized and characterized. KRSH consists of four amino acids; lysine and arginine contain positively charged groups that help KRSH target the mitochondria, while tyrosine and cysteine neutralize excessive endogenous ROS, thereby inhibiting tumorigenesis.

Results

The results indicated that KRSH is specifically inhibiting the growth of HeLa and MCF-7 cancer cell lines. However, MCF10A cells can resist the effects of KRSH even in a relative higher concentration. The dichloro-dihydro-fluorescein diacetate and MitoSOX^TM Red assay suggested that KRSH drastically decreased the level of ROS in cancer cells. The mitochondrial depolarization assay indicated that treatment with KRSH at a dose of 50 nM may decrease the mitochondrial membrane potential leading to apoptosis of HeLa and MCF-7 cells.

Conclusion

In other studies, investigating rat liver mitochondria, the uptake of KRSH may reach 80% compared with that for mitoquinone. Therefore, KRSH was designed as a superior peptide antioxidant and a mitochondria-targeting anticancer agent.

Caveolin-1 knockdown increases the therapeutic sensitivity of lung cancer to cisplatin-induced apoptosis by repressing Parkin-related mitophagy and activating the ROCK1 pathway

Chemotherapy is the first-line treatment option for patients with lung cancer. However, therapeutic resistance occurs through an incompletely understood mechanism. Our research wants to investigate the influence of Caveolin-1 (Cav-1) on the therapeutic sensitivity of lung cancer in vitro. Results in this study demonstrated that Cav-1 levels were markedly inhibited in A549 lung cancer cells after exposure to cisplatin. Knockdown of caveolin further enhanced cisplatin-triggered cancer death in A549 cells. The functional investigation demonstrated that Cav-1 inhibition amplified the mitochondrial stress signaling induced by cisplatin, as evidenced by the mitochondrial reactive oxygen species burst, cellular metabolic disruption, mitochondrial membrane potential reduction, and mitochondrial caspase-9-related apoptosis activation. At the molecular level, cav-1 augmented cisplatin-mediated mitochondrial damage by inhibiting Parkin-related mitochondrial autophagy. Mitophagy activation effectively attenuated the promotive impact of Cav-1 knockdown on mitochondrial damage and cell death. Furthermore, our data indicated that Cav-1 affected Parkin-related mitophagy by activating the Rho-associated coiled-coil kinase 1 (ROCK1) pathway; inhibition of the ROCK1 axis prevented cav-1 knockdown-mediated cell death and mitochondrial damage. Taken together, our results provide ample data illuminate the necessary action exerted by Cav-1 on affecting cisplatin-related therapeutic resistance. Silencing of Cav-1 inhibited Parkin-related mitophagy, thus amplifying cisplatin-mediated mitochondrial apoptotic signaling. This finding identifies the Cav-1/ROCK1/Parkin/mitophagy axis as a potential target to overcome cisplatin-related resistance in lung cancer cells.

Mst1 deletion reduces septic cardiomyopathy via activating Parkin-related mitophagy

Cardiomyocyte function and viability are highly modulated by mammalian Ste20-like kinase 1 (Mst1)-Hippo pathway and mitochondria. Mitophagy, a kind of mitochondrial autophagy, is a protective program to attenuate mitochondrial damage. However, the relationship between Mst1 and mitophagy in septic cardiomyopathy has not been explored. In the present study, Mst1 knockout mice were used in a lipopolysaccharide (LPS)-induced septic cardiomyopathy model. Mitophagy activity was measured via immunofluorescence, Western blotting, and enzyme-linked immunosorbent assay. Pathway blocker and small interfering RNA were used to perform the loss-of-function assay. The results demonstrated that Mst1 was rapidly increased in response to LPS stress. Knockout of Mst1 attenuated LPS-mediated inflammation damage, reduced cardiomyocyte death, and improved cardiac function. At the molecular levels, LPS treatment activated mitochondrial damage, such as mitochondrial respiratory dysfunction, mitochondrial potential reduction, mitochondrial ATP depletion, and caspase family activation. Interestingly, in response to mitochondrial damage, Mst1 deletion activated mitophagy which attenuated LPS-mediated mitochondrial damage. However, inhibition of mitophagy via inhibiting parkin mitophagy abolished the protective influences of Mst1 deletion on mitochondrial homeostasis and cardiomyocyte viability. Overall, our results demonstrated that septic cardiomyopathy is linked to Mst1 upregulation which is followed by a drop in the protective mitophagy.

Mst1 overexpression combined with Yap knockdown augments thyroid carcinoma apoptosis via promoting MIEF1-related mitochondrial fission and activating the JNK pathway

Background

Cancer cell viability is strongly modulated by the Hippo pathway, which includes mammalian STE20-like protein kinase 1 (Mst1) and yes-associated protein (Yap). Although the roles of Mst1 and Yap in thyroid carcinoma cell death have been fully addressed, no study has determined whether differential modification of Mst1 and Yap could further suppress thyroid carcinoma progression. The aim of our study was to explore the antiapoptotic effects exerted by combined Mst1 overexpression and Yap knockdown in thyroid carcinoma MDA-T32 cells in vitro.

Methods

Mst1 adenovirus and Yap shRNA were transfected into MDA-T32 cells to overexpress Mst1 and inhibit Yap, respectively. Cell viability and death were determined via an MTT assay, a TUNEL assay and western blotting. Mitochondrial function, mitochondrial fission and pathway studies were performed via western blotting and immunofluorescence.

Results

The results of our study showed that combined Mst1 overexpression and Yap knockdown further augmented MDA-T32 cell death by mediating mitochondrial damage. In addition, cancer cell migration and proliferation were suppressed by combined Mst1 overexpression and Yap knockdown. At the molecular level, mitochondrial membrane potential, ATP production, respiratory function, and caspase-9-related apoptosis were activated by combined Mst1 overexpression and Yap knockdown. Further, we found that fatal mitochondrial fission was augmented by combined Mst1 overexpression and Yap knockdown in a manner dependent on the JNK-MIEF1 pathway. Inhibition of JNK-MIEF1 pathway activity abolished the proapoptotic effects exerted by Mst1/Yap on MDA-T32 cells.

Conclusions

Taken together, our data suggest that Mst1 activation and Yap inhibition coordinate to augment thyroid cancer cell death by controlling the JNK-MIEF1-mitochondria pathway, suggesting that differential regulation of the core Hippo pathway components is potentially a novel therapeutic tool for the treatment of thyroid cancer.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0860-8) contains supplementary material, which is available to authorized users.

Sodium sulfide selectively induces oxidative stress, DNA damage, and mitochondrial dysfunction and radiosensitizes glioblastoma (GBM) cells

Glioblastoma (GBM) has a poor prognosis despite intensive treatment with surgery and chemoradiotherapy. Previous studies using dose-escalated radiotherapy have demonstrated improved survival; however, increased rates of radionecrosis have limited its use. Development of radiosensitizers could improve patient outcome. In the present study, we report the use of sodium sulfide (Na₂S), a hydrogen sulfide (H₂S) donor, to selectively kill GBM cells (T98G and U87) while sparing normal human cerebral microvascular endothelial cells (hCMEC/D3). Na₂S also decreased mitochondrial respiration, increased oxidative stress and induced γH2AX foci and oxidative base damage in GBM cells. Since Na₂S did not significantly alter T98G capacity to perform non-homologous end-joining or base excision repair, it is possible that GBM cell killing could be attributed to increased damage induction due to enhanced reactive oxygen species production. Interestingly, Na₂S enhanced mitochondrial respiration, produced a more reducing environment and did not induce high levels of DNA damage in hCMEC/D3. Taken together, this data suggests involvement of mitochondrial respiration in Na₂S toxicity in GBM cells. The fact that survival of LN-18 GBM cells lacking mitochondrial DNA (ρ⁰) was not altered by Na₂S whereas the survival of LN-18 ρ⁺ cells was compromised supports this conclusion. When cells were treated with Na₂S and photon or proton radiation, GBM cell killing was enhanced, which opens the possibility of H₂S being a radiosensitizer. Therefore, this study provides the first evidence that H₂S donors could be used in GBM therapy to potentiate radiation-induced killing.

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Sodium sulfide selectively kills GBM cells by inducing DNA damage.

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Sodium sulfide induces mitochondrial dysfunction and oxidative stress in GBM cells.

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Toxicity to sodium sulfide is dependent on mitochondrial respiration.

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Sodium sulfide radiosensitizes GBM cells to photon and proton radiation.

N-Acetylcysteine and Sulodexide Reduce the Prothrombotic Effect of Uremic Serum on the Venous Endothelial Cells

BACKGROUND/AIMS

Thromboembolic episodes are a frequent problem in end stage renal failure patients. The pathomechanism of the disorder is complex, including bioincompatibility of renal replacement therapy, endothelial dysfunction, increased blood level of procoagulant factors and uremic toxins. We studied changes in the functional properties of venous endothelial cells (VEC) in the presence of uremic serum and evaluated their possible modulation by N-acetylcysteine (NAC) or sulodexide (SUL).

METHODS

Serum samples from 12 uremic patients treated with hemodialysis were studied ex vivo on in vitro cultured VEC. In separate experiments, NAC 1 mmol/L or SUL 0.5 LRU/mL were added to uremic serum samples. Both changes in the gene expression and secretory activity of VEC were studied.

RESULTS

Uremic serum increased the expression of the following genes: IL6 +97%, p < 0.002; VEGF +28%, p < 0.002; vWF +47%, p < 0.002; PECAM +76%, p < 0.002; ICAM-1 +275%, p < 0.002; t-PA +96%, p < 0.002. Changes in gene expression were reflected by the increased secretory activity of VEC treated with the uremic serum. Exposure of VEC to uremic serum supplemented with NAC or SUL resulted in weaker stimulation of the studied genes' expression. Also, secretion of the studied solutes, with the exception of ICAM-1, was reduced in the presence of NAC: IL6 -34%, p < 0.01; VEGF -40%, p < 0.005; vWF -25%, p < 0.001; t-PA -47%, p < 0.01, and MMP9 -37%, p < 0.001. SUL reduced the uremic serum-induced secretion of all solutes: IL6 -24%, p < 0.05; ICAM-1 -43%, p < 0.01; VEGF -38%, p < 0.01; vWF -23%, p < 0.01; t-PA -49%, p < 0.01, and MMP9 -25%, p < 0.05.

CONCLUSIONS

Uremic serum induces prothrombotic changes in VEC, which may cause a predisposition to thrombotic disorders in patients with renal failure. NAC and SUL reduce the effects of the uremic serum in VEC, which suggests their potential therapeutic application in uremic patients.

N-Acetyl-l-Cysteine Supplement in Early Life or Adulthood Reduces Progression of Diabetes in Nonobese Diabetic Mice

BACKGROUND

Oxidative stress contributes to the pathologic process leading to the development, progression, and complications of type 1 diabetes (T1D).

OBJECTIVE

The aim of this study was to investigate the effect of the antioxidant N-acetyl-l-cysteine (NAC), supplemented during early life or adulthood on the development of T1D.

METHODS

NAC was administered to nonobese diabetic (NOD) female mice during pregnancy and lactation, and the development of diabetes was followed in offspring. In an additional set of experiments, offspring of untreated mice were given NAC during adulthood, and the development of T1D was followed. Morbidity rate, insulitis and serum cytokines were measured in the 2 sets of experiments. In addition, markers of oxidative stress, glutathione, lipid peroxidation, total antioxidant capacity and activity of antioxidant enzymes, were followed.

RESULTS

Morbidity rate was reduced in both treatment protocols. A decrease in interferon γ, tumor necrosis factor α, interleukin 1α, and other type 1 diabetes-associated proinflammatory cytokines was found in mice supplemented with NAC in adulthood or during early life compared with control NOD mice. The severity of insulitis was higher in control NOD mice than in treated groups. NAC administration significantly reduced oxidative stress, as determined by reduced lipid peroxidation and increased total antioxidant capacity in serum and pancreas of mice treated in early life or in adulthood and increased pancreatic glutathione when administrated in adulthood. The activity of antioxidant enzymes was not affected in mice given NAC in adulthood, whereas an increase in the activity of superoxide dismutase and catalase was demonstrated in the pancreas of their offspring.

CONCLUSION

NAC decreased morbidity of NOD mice by attenuating the immune response, presumably by eliminating oxidative stress, and might be beneficial in reducing morbidity rates of T1D in high-risk individuals.

Yap-Hippo promotes A549 lung cancer cell death via modulating MIEF1-related mitochondrial stress and activating JNK pathway

Although the role of Yes-associated protein (Yap) has been described in the progression of lung cancer, the downstream effector of the Yap-Hippo pathway has not been identified. Accordingly, the aim of our study is to explore whether Yap modulates the activity of lung cancer by controlling mitochondrial elongation factor 1 (MIEF1)-related mitochondrial stress in a manner dependent on the JNK pathway. Cell viability was determined via MTT, LDH release and immunofluorescence assays. ATP production, the mitochondrial membrane potential, and caspase-9 activity were investigated to assess mitochondrial function. siRNA transfection and pathway blockers were used to observe the roles of MIEF1 and JNK in Yap-modulated cell viability in lung cancer cells in vitro. Yap deletion reduced cell viability in A549 and H358 lung cancer cells. At the molecular level, Yap deletion promoted mitochondrial dysfunction, as evidenced by the decreased mitochondrial potential, increased mitochondrial oxidative stress, augmented mitochondrial pro-apoptotic factor leakage and elevated caspase-9 activity. In addition, we found that Yap modulated mitochondrial stress via MIEF1 and that loss of MIEF1 abolished the regulatory actions of Yap on mitochondrial stress and cell viability. Besides, we provided evidence to support the necessary role of JNK in Yap-mediated MIEF1 upregulation. Inhibition of JNK abolished the promotive effect of Yap deletion on MIEF1 activation. Taken together, our results identified the JNK-MIEF1 pathway and mitochondrial stress as downstream effectors of Yap in lung cancer. This finding suggests a novel approach for the treatment of lung cancer in clinical practice.

Nurr1 Promotes Lung Cancer Apoptosis Via Enhancing Mitochondrial Stress and p53-Drp1 Pathway

OBJECTIVE

Mitochondrial homeostasis is vital for the progression of lung cancer. Nurr1 has been identified as a novel mediator of mitochondrial homeostasis in several types of cancers. The aim of our study was to investigate whether Nurr1 modulates the viability of A549 lung cancer cells by inducing mitochondrial dysfunction, with a focus on the p53-Drp1 signaling pathway.

METHODS

western blotting, ELISA and immunofluorescence assay was used to verify the alterations of cell death. siRNA was used to determine the role of p53-Drp1 pathway in lung cancer death.

RESULTS

Nurr1 was downregulated in A549 lung cancer cells compared to normal pulmonary epithelial cells. Interestingly, overexpression of Nurr1 reduced the viability of A549 lung cancer cells by activating apoptosis and mitochondrial stress. At the molecular level, we provide data to support the regulatory effects of Nurr1 on the p53-Drp1 signaling pathway. Blockade of the p53-Drp1 signaling pathway abolished the proapoptotic action of Nurr1 on A549 cells and sustained mitochondrial homeostasis.

CONCLUSION

Taken together, our results depict the tumor-suppressive role played by Nurr1 in A549 lung cancer in vitro and show that the anticancer effects of Nurr1 are executed via triggering of mitochondrial dysfunction and activation of the p53-Drp1 signaling pathway.

Endothelial dysfunction and platelet hyperactivity in type 2 diabetes mellitus: molecular insights and therapeutic strategies

The incidence and prevalence of diabetes mellitus is rapidly increasing worldwide at an alarming rate. Type 2 diabetes mellitus (T2DM) is the most prevalent form of diabetes, accounting for approximately 90-95% of the total diabetes cases worldwide. Besides affecting the ability of body to use glucose, it is associated with micro-vascular and macro-vascular complications. Augmented atherosclerosis is documented to be the key factor leading to vascular complications in T2DM patients. The metabolic milieu of T2DM, including insulin resistance, hyperglycemia and release of excess free fatty acids, along with other metabolic abnormalities affects vascular wall by a series of events including endothelial dysfunction, platelet hyperactivity, oxidative stress and low-grade inflammation. Activation of these events further enhances vasoconstriction and promotes thrombus formation, ultimately resulting in the development of atherosclerosis. All these evidences are supported by the clinical trials reporting the importance of endothelial dysfunction and platelet hyperactivity in the pathogenesis of atherosclerotic vascular complications. In this review, an attempt has been made to comprehensively compile updated information available in context of endothelial and platelet dysfunction in T2DM.

N-Acetyl Cysteine Restores Limb Function, Improves Mitochondrial Respiration, and Reduces Oxidative Stress in a Murine Model of Critical Limb Ischaemia

OBJECTIVE/BACKGROUND

The aim of this study was to investigate whether antioxidant therapy might decrease oxidative stress related deleterious effects in the setting of critical limb ischaemia (CLI).

METHODS

Twenty Swiss mice were submitted to sequential right femoral and iliac ligatures; the left limb served as control. The mice were assigned to two groups: in the first group (no-treatment group, n = 10) no treatment was administered; in the second group (N-acetyl cysteine [NAC] group, n = 10) NAC was administered by dissolution in drinking water for 4 weeks, starting on day 7, when CLI was effective. Clinical and functional scores were assessed by two blinded investigators. Mice were killed on day 40 and mitochondrial respiratory chain complex activities, calcium retention capacity, oxidative stress, and histological analysis were analysed.

RESULTS

Ischaemic muscles in the no-treatment group showed significantly impaired mitochondrial respiration and calcium retention capacity, with increased production of reactive oxygen species; but no statistical difference was noticed when comparing ischaemic muscles in the NAC group (n = 10) to contralateral muscles (n = 10) and to control muscles in the no-treatment group (n = 10). Ischaemic muscles in the no-treatment group exhibited myopathic features such as wider range in fibre size, rounded shape, centrally located nuclei, and smaller cross sectional areas, but none of these features were observed in contralateral muscles or in NAC-group muscles (ischaemic or controls).

CONCLUSION

Targeting inhibition of oxidative stress may be a potential therapeutic strategy for muscle protection in CLI and might be considered as potential adjunctive therapy to revascularisation procedures.