Endogenous SOD2 (Superoxide Dismutase) Regulates Platelet-Dependent Thrombin Generation and Thrombosis During Aging

Commonalities of platelet dysfunction in heart failure with preserved ejection fraction and underlying comorbidities

Heart failure with preserved ejection fraction (HFpEF) is characterized by a lack of a specific targeted treatment and a complex, partially unexplored pathophysiology. Common comorbidities associated with HFpEF are hypertension, atrial fibrillation, obesity and diabetes. These comorbidities, combined with advanced age, play a crucial role in the initiation and development of the disease through the promotion of systemic inflammation and consequent changes in cardiac phenotype. In this context, we suggest platelets as important players due to their emerging role in vascular inflammation. This review provides an overview of the role of platelets in HFpEF and its associated comorbidities, including hypertension, atrial fibrillation, obesity and diabetes mellitus, as well as the impact of age and sex on platelet function. These major HFpEF-associated comorbidities present alterations in platelet behaviour and in features linked to platelet size, content and reactivity. The resulting dysfunctional platelets can contribute to further increase inflammation, oxidative stress and endothelial dysfunction, suggesting an active role of these cells in the initiation and progression of HFpEF. Recent evidence shows that reduced platelet count and elevated mean platelet volume are associated with worsening heart failure in HFpEF patients. However, the specific mechanisms by which platelets contribute to HFpEF development and progression are still largely unexplored, with only a few studies investigating platelet function in HFpEF. We discuss the limited yet significant body of research investigating platelet function in HFpEF, emphasizing the need for more comprehensive studies. Additionally, we explore the potential mechanisms through which platelets may influence HFpEF, such as their interactions with the vascular endothelium and the secretion of bioactive molecules like cytokines, chemokines and RNA molecules. These interactions and secretions may play a role in modulating vascular inflammation and contributing to the pathophysiological landscape of HFpEF. The review underscores the necessity for future research to elucidate the precise contributions of platelets to HFpEF, aiming to potentially identify novel therapeutic targets and improve patient outcomes. The evidence presented herein supports the hypothesis that platelets are not merely passive bystanders but active participants in the pathophysiology of HFpEF and its comorbidities.

Platelet Reactive Oxygen Species, Oxidised Lipid Stress, Current Perspectives, and an Update on Future Directions

Blood platelets are anucleate cells that play a vital role in haemostasis, innate immunity, angiogenesis, and wound healing. However, the inappropriate activation of platelets also contributes to vascular inflammation, atherogenesis, and thrombosis. Platelet activation is a highly complex receptor-mediated process that involves a multitude of signalling intermediates in which Reactive Oxygen Species (ROS) are proposed to play an important role. However, like for many cells, changes in the balance of ROS generation and/or scavenging in disease states may lead to the adoption of maladaptive platelet phenotypes. Here, we review the diverse roles of ROS in platelet function and how ROS are linked to specific platelet activation pathways. We also examine how changes in disease, particularly the plasma oxidised low-density lipoprotein (oxLDL), affect platelet ROS generation and platelet function.

BCL-2 dependence is a favorable predictive marker of response to therapy for chronic lymphocytic leukemia

BACKGROUND

Established genetic biomarkers in chronic lymphocytic leukemia (CLL) have been useful in predicting response to chemoimmunotherapy but are less predictive of response to targeted therapies. With several such targeted therapies now approved for CLL, identifying novel, non-genetic predictive biomarkers of response may help to select the optimal therapy for individual patients.

METHODS

We coupled data from a functional precision medicine technique called BH3-profiling, which assesses cellular cytochrome c loss levels as indicators for survival dependence on anti-apoptotic proteins, with multi-omics data consisting of targeted and whole-exome sequencing, genome-wide DNA methylation profiles, RNA-sequencing, protein and functional analyses, to identify biomarkers for treatment response in CLL patients.

RESULTS

We initially studied 73 CLL patients from a discovery cohort. We found that greater dependence on the anti-apoptotic BCL-2 protein was associated with prognostically favorable genetic biomarkers. Furthermore, BCL-2 dependence was strongly associated with gene expression patterns and signaling pathways that suggest a more targeted drug-sensitive milieu and was predictive of drug responses. We subsequently demonstrated that these associations were causal in cell lines and additional CLL patient samples. To validate the findings from our discovery cohort and in vitro studies, we utilized primary CLL cells from 54 additional patients treated on a prospective, phase-2 clinical trial of the BTK inhibitor ibrutinib given in combination with chemoimmunotherapy (fludarabine, cyclophosphamide, rituximab) and confirmed in this independent dataset that higher BCL-2 dependence predicted favorable clinical response, independent of the genetic background of the CLL cells.

CONCLUSION

We comprehensively defined BCL-2 dependence as a potential functional and predictive biomarker of treatment response in CLL, underscoring the importance of characterizing apoptotic signaling in CLL to stratify patients beyond genetic markers and identifying novel combinations to exploit BCL-2 dependence therapeutically. Our approach has the potential to help optimize targeted therapy combinations for CLL patients.

The Fifth Annual Symposium of the Midwest Aging Consortium

As the healthcare burden caused by an increasingly aging population rapidly rises, a pressing need exists for innovative geroscience research that can elucidate aging mechanisms and precipitate the development of therapeutic interventions to support healthy aging. The Fifth Annual Midwest Aging Consortium Aging Research symposium, held from April 28 to 30, 2024, was hosted by The Ohio State University in Columbus, Ohio, and featured presentations from investigators across the Midwestern United States. This report summarizes the research presented at the symposium, whose topics included cellular senescence and the aging brain, metabolism and metabolic interventions, nutrition, redox mechanisms and biomarkers, and stress mechanisms. Abstract presentations and short talks highlighted early-stage and young investigators, whereas 2 keynote presentations anchored the symposium. Overall, this symposium showed the robustness of aging research in the Midwest and underscored the advantages of a collaborative approach to geroscience research.

Proteomic Composition of Acute Ischemic Stroke Thrombi Retrieved via Endovascular Thrombectomy Is Associated with Stroke Etiology

The objective of this study is to investigate the protein components of acute ischemic stroke (AIS) thrombi using four-dimensional independent data acquisition (4D-DIA) proteomics and reveal the correlations between thrombotic protein components and AIS etiology. From April to September 2023, we enrolled a total of 30 patients who underwent endovascular thrombectomy at our institute and were diagnosed in accordance with large artery atherosclerosis (LAA; n = 15) or cardioembolism (CE; n = 15). Thromboembolic material was collected for 4D-DIA proteomic detection. We then analyzed it for differentially expressed proteins (DEPs; fold change [FC] ≥ 1.5 or ≤ 0.67), performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, and mapped protein-protein interactions (PPIs). In the 30 retrieved clots, 5115 proteins were expressed. Of these, we screened 246 DEPs between the LAA and CE groups, such as histone H4, collagen α1, and differentially expressed in neoplastic versus normal cells domain-containing protein 6A. GO analysis revealed that the DEPs' most important biological process was cellular process, the most important Cell Component was cell part, the molecular function was binding, and the most significantly enriched pathway was thiamine metabolism. PPI results revealed complicated interactions among these DEPs, of which superoxide dismutase, catalase, and γ-enolase might play important roles. This study outlines a promising molecular approach to differentiating the etiology of AIS between CE and LAA through the proteomics of retrieved thrombi, which might also inform future research into thrombotic biology.

Comprehensive lung microbial gene and genome catalogs assist the mechanism survey of Mesomycoplasma hyopneumoniae strains causing pig lung lesions

Understanding the community structure of the lower respiratory tract microbiome is crucial for elucidating its roles in respiratory tract diseases. However, there are few studies about this topic due to the difficulty in obtaining microbial samples from both healthy and disease individuals. Here, using 744 high-depth metagenomic sequencing data of lower respiratory tract microbial samples from 675 well-phenotyped pigs, we constructed a lung microbial gene catalog containing the largest scale of 10,031,593 nonredundant genes to date, 44.8% of which are novel. We obtained 356 metagenome-assembled genomes (MAGs) which were further clustered into 256 species-level genome bins with 41.8% being first reported in the current databases. Based on these data sets and through integrated analysis of the isolation of the related bacterial strains, in vitro infection, and RNA sequencing, we identified and confirmed that Mesomycoplasma hyopneumoniae (M. hyopneumoniae) MAG_47 and its adhesion-related virulence factors (VFs) were associated with lung lesions in pigs. Differential expression levels of adhesion- and immunomodulation-related VFs likely determined the heterogenicity of adhesion and pathogenicity among M. hyopneumoniae strains. M. hyopneumoniae adhesion activated several pathways, including nuclear factor kappa-light-chain-enhancer of activated B, mitogen-activated protein kinase, cell apoptosis, T helper 1 and T helper 2 cell differentiation, tumor necrosis factor signaling, interleukin-6/janus kinase 2/signal transducer and activator of transcription signaling, and response to reactive oxygen species, leading to cilium loss, epithelial cell‒cell barrier disruption, and lung tissue lesions. Finally, we observed the similar phylogenetic compositions of the lung microbiome between humans with Mycoplasma pneumoniae and pigs infected with M. hyopneumoniae. The results provided important insights into pig lower respiratory tract microbiome and its relationship with lung health.

Loss of endogenous Nox2-NADPH oxidase does not prevent age-induced platelet activation and arterial thrombosis in mice

Background

Reactive oxygen species are known to contribute to platelet hyperactivation and thrombosis during aging; however, the mechanistic contribution of the specific oxidative pathway remains elusive.

Objectives

We hypothesized that during aging, endogenous Nox2-NADPH oxidase contributes to platelet reactive oxygen species accumulation and that loss of Nox2 will protect from platelet activation and thrombosis.

Methods

We studied littermates of Nox2 knockout (Nox2-KO) and -wild-type (Nox2-WT) mice at young (3-4 months) and old (18-20 months) age. Within platelets, we examined the expression of subunits of NADPH oxidase and enzyme activity, oxidant levels, activation markers, aggregation, and secretion. We also assessed susceptibility to in vivo thrombosis in 2 experimental models.

Results

While aged Nox2-WT mice displayed increased mRNA levels for Nox2, aged Nox2-KO mice showed an increase in Nox4 mRNA. However, neither the protein levels of several subunits nor the activity of NADPH oxidase were found to be altered by age or genotype. Both aged Nox2-WT and aged Nox2-KO mice exhibited similar enhancement in levels of platelet oxidants, granule release, αIIbβ3 activation, annexin V binding, aggregation and secretion, and a greater susceptibility to platelet-induced pulmonary thrombosis compared with young mice. In a photochemical injury model, adoptive transfer of platelets from aged Nox2-WT or Nox2-KO mice to the aged host mice resulted in a similar time to develop occlusive thrombus in the carotid artery. These findings suggest that loss of endogenous Nox2 does not protect against age-related platelet activation and arterial thrombosis in mice.

Conclusion

We conclude that Nox2 is not an essential mediator of prothrombotic effects associated with aging.

Fisetin disrupts mitochondrial homeostasis via superoxide dismutase 2 acetylation in pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PDAC) is one of the most lethal malignant tumors with an urgent need for precision medicine strategies. The present study seeks to assess the antitumor effects of fisetin, and characterize its impact on PDAC. Multi-omic approaches include proteomic, transcriptomic, and metabolomic analyses. Further validation includes the assessment of mitochondria-derived reactive oxygen species (mtROS), mitochondrial membrane potential, as well as ATP generation. Molecular docking, immunoprecipitation, and proximity ligation assay were used to detect the interactions among fiseitn, superoxide dismutase 2 (SOD2), and sirtuin 2 (SIRT2). We showed that fisetin disrupted mitochondrial homeostasis and induced SOD2 acetylation in PDAC. Further, we produced site mutants to determine that fisetin-induced mtROS were dependent on SOD2 acetylation. Fisetin inhibited SIRT2 expression, thus blocking SOD2 deacetylation. SIRT2 overexpression could impede fisetin-induced SOD2 acetylation. Additionally, untargeted metabolomic analysis revealed an acceleration of folate metabolism with fisetin. Collectively, our findings suggest that fisetin disrupts mitochondrial homeostasis, eliciting an important cancer-suppressive role; thus, fisetin may serve as a promising therapeutic for PDAC.

Aging-related alterations in mechanistic target of rapamycin signaling promote platelet hyperreactivity and thrombosis

BACKGROUND

Aging is an independent risk factor for the development of cardiovascular, thrombotic, and other chronic diseases. However, mechanisms of platelet hyperactivation in aging remain poorly understood.

OBJECTIVES

Here, we examine whether and how aging alters intracellular signaling in platelets to support platelet hyperactivity and thrombosis.

METHODS

Quantitative mass spectrometry with tandem mass tag labeling systematically measured protein phosphorylation in platelets from healthy aged (>65 years) and young human (<45 years) subjects. The role of platelet mechanistic target of rapamycin (mTOR) in aging-induced platelet hyperreactivity was assessed using pharmacologic mTOR inhibition and a platelet-specific mTOR-deficient mouse model (mTORplt-/-).

RESULTS

Quantitative phosphoproteomics uncovered differential site-specific protein phosphorylation within mTOR, Rho GTPase, and MAPK pathways in platelets from aged donors. Western blot confirmed constitutive activation of the mTOR pathway in platelets from both aged humans and mice, which was associated with increased aggregation compared with that in young controls. Inhibition of mTOR with either Torin 1 in aged humans or genetic deletion in aged mice reversed platelet hyperreactivity. In a collagen-epinephrine pulmonary thrombosis model, aged wild-type (mTORplt+/+) mice succumbed significantly faster than young controls, while time to death of aged mTORplt-/- mice was similar to that of young mTORplt+/+ mice. Mechanistically, we noted increased Rac1 activation and levels of mitochondrial reactive oxygen species in resting platelets from aged mice, as well as increased p38 phosphorylation upstream of thromboxane generation following agonist stimulation.

CONCLUSION

Aging-related changes in mTOR phosphorylation enhance Rac1 and p38 activation to enhance thromboxane generation, platelet hyperactivity, and thrombosis.

Aging and Antithrombotic Treatment

Significance: Several aging-related pathophysiological mechanisms have been described to contribute to increased thrombotic risk in the elderly, including oxidative stress, endothelial dysfunction, and platelet and coagulation cascade activation. Antithrombotic treatment in the elderly should be individualized. Recent Advances: Recent studies have clarified some pathophysiological mechanisms of enhanced oxidative stress and thrombotic alterations in older adults. In the last decade, randomized trials have evaluated different antithrombotic strategies to reduce the risk of cardiovascular events in these patients. Critical Issues: The proportion of elderly patients included in clinical trials is generally low, thus not reflecting the daily clinical practice. There is no consensus on the most appropriate antithrombotic treatment in the elderly, also considering that bleeding risk management may be challenging in this high-risk subgroup of patients. Routine antiplatelet treatment is not a valid strategy for the primary prevention of cardiovascular events given the associated high risk of bleeding. In elderly patients with acute coronary syndrome, low-dose prasugrel or clopidogrel, shorter dual antiplatelet therapy, and no pretreatment before stent placement should be considered. Advanced age should not be the only reason for the underuse of oral anticoagulation in patients with atrial fibrillation, with direct oral anticoagulants preferred over warfarin for stroke prevention. Instead, a case-by-case clinical evaluation is warranted based on patient's bleeding risk also. Future Directions: There is a need for a structured tailored approach to manage thrombotic risk in elderly patients. The choice of the most appropriate antithrombotic treatment should balance efficacy and safety to reduce the risk of bleeding.

Altered dynamics of calcium fluxes and mitochondrial metabolism in platelet activation-related disease and aging

Understanding the mechanisms controlling platelet function is crucial for exploring potential therapeutic targets related to atherothrombotic pathologies and primary hemostasis disorders. Our research, which focuses on the role of platelet mitochondria and Ca2+ fluxes in platelet activation, the formation of the procoagulant phenotype, and thrombosis, has significant implications for the development of new therapeutic strategies. Traditionally, Ca2+-dependent cellular signaling has been recognized as a determinant process throughout the platelet activation, controlled primarily by store-operated Ca2+ entry and the PLC-PKC signaling pathway. However, despite the accumulated knowledge of these regulatory mechanisms, the effectiveness of therapy based on various commonly used antiplatelet drugs (such as acetylsalicylic acid and clopidogrel, among others) has faced challenges due to bleeding risks and reduced efficacy associated with the phenomenon of high platelet reactivity. Recent evidence suggests that platelet mitochondria could play a fundamental role in these aspects through Ca2+-dependent mechanisms linked to apoptosis and forming a procoagulant phenotype. In this context, the present review describes the latest advances regarding the role of platelet mitochondria and Ca2+ fluxes in platelet activation, the formation of the procoagulant phenotype, and thrombosis.

Lung EC-SOD Overexpression Prevents Hypoxia-Induced Platelet Activation and Lung Platelet Accumulation

Pulmonary hypertension (PH) is a progressive disease marked by pulmonary vascular remodeling and right ventricular failure. Inflammation and oxidative stress are critical in PH pathogenesis, with early pulmonary vascular inflammation preceding vascular remodeling. Extracellular superoxide dismutase (EC-SOD), a key vascular antioxidant enzyme, mitigates oxidative stress and protects against inflammation and fibrosis in diverse lung and vascular disease models. This study utilizes a murine hypobaric hypoxia model to investigate the role of lung EC-SOD on hypoxia-induced platelet activation and platelet lung accumulation, a critical factor in PH-related inflammation. We found that lung EC-SOD overexpression blocked hypoxia-induced platelet activation and platelet accumulation in the lung. Though lung EC-SOD overexpression increased lung EC-SOD content, it did not impact plasma extracellular SOD activity. However, ex vivo, exogenous extracellular SOD treatment specifically blunted convulxin-induced platelet activation but did not blunt platelet activation with thrombin or ADP. Our data identify platelets as a novel target of EC-SOD in response to hypoxia, providing a foundation to advance the understanding of dysregulated redox signaling and platelet activation in PH and other chronic hypoxic lung diseases.

Metformin induction of heat shock factor 1 activation and the mitochondrial unfolded protein response alleviate cardiac remodeling in spontaneously hypertensive rats

Heart failure and cardiac remodeling are both characterized by mitochondrial dysfunction. Healthy mitochondria are required for adequate contractile activity and appropriate regulation of cell survival. In the mammalian heart, enhancement of the mitochondrial unfolded protein response (UPRmt) is cardioprotective under pressure overload conditions. We explored the UPRmt and the underlying regulatory mechanism in terms of hypertension-induced cardiac remodeling and the cardioprotective effect of metformin. Male spontaneously hypertensive rats and angiotensin II-treated neonatal rat cardiomyocytes were used to induce cardiac hypertrophy. The results showed that hypertension induced the formation of aberrant mitochondria, characterized by a reduced mtDNA/nDNA ratio and swelling, as well as lower levels of mitochondrial complexes I to V and inhibition of the expression of one protein subunit of each of complexes I to IV. Such changes eventually enlarged cardiomyocytes and increased cardiac fibrosis. Metformin treatment increased the mtDNA/nDNA ratio and regulated the UPRmt, as indicated by increased expression of activating transcription factor 5, Lon protease 1, and heat shock protein 60, and decreased expression of C/EBP homologous protein. Thus, metformin improved mitochondrial ultrastructure and function in spontaneously hypertensive rats. In vitro analyses revealed that metformin reduced the high levels of angiotensin II-induced mitochondrial reactive oxygen species in such animals and stimulated nuclear translocation of heat shock factor 1 (HSF1). Moreover, HSF1 small-interfering RNA reduced the metformin-mediated improvements in mitochondrial morphology and the UPRmt by suppressing hypertrophic signals and cardiomyocyte apoptosis. These results suggest that HSF1/UPRmt signaling contributes to the beneficial effects of metformin. Metformin-mediated targeting of mitochondrial protein homeostasis and modulation of HSF1 levels have potential therapeutic implications in terms of cardiac remodeling.

Targeting Cysteine Oxidation in Thrombotic Disorders

Oxidative stress increases the risk for clinically significant thrombotic events, yet the mechanisms by which oxidants become prothrombotic are unclear. In this review, we provide an overview of cysteine reactivity and oxidation. We then highlight recent findings on cysteine oxidation events in oxidative stress-related thrombosis. Special emphasis is on the signaling pathway induced by a platelet membrane protein, CD36, in dyslipidemia, and by protein disulfide isomerase (PDI), a member of the thiol oxidoreductase family of proteins. Antioxidative and chemical biology approaches to target cysteine are discussed. Lastly, the knowledge gaps in the field are highlighted as they relate to understanding how oxidative cysteine modification might be targeted to limit thrombosis.

NLRP3-Induced NETosis: A Potential Therapeutic Target for Ischemic Thrombotic Diseases?

Ischemic thrombotic disease, characterized by the formation of obstructive blood clots within arteries or veins, is a condition associated with life-threatening events, such as stroke, myocardial infarction, deep vein thrombosis, and pulmonary embolism. The conventional therapeutic strategy relies on treatments with anticoagulants that unfortunately pose an inherent risk of bleeding complications. These anticoagulants primarily target clotting factors, often overlooking upstream events, including the release of neutrophil extracellular traps (NETs). Neutrophils are integral components of the innate immune system, traditionally known for their role in combating pathogens through NET formation. Emerging evidence has now revealed that NETs contribute to a prothrombotic milieu by promoting platelet activation, increasing thrombin generation, and providing a scaffold for clot formation. Additionally, NET components enhance clot stability and resistance to fibrinolysis. Clinical and preclinical studies have underscored the mechanistic involvement of NETs in the pathogenesis of thrombotic complications, since the clots obtained from patients and experimental models consistently exhibit the presence of NETs. Given these insights, the inhibition of NETs or NET formation is emerging as a promising therapeutic approach for ischemic thrombotic diseases. Recent investigations also implicate a role for the nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome as a mediator of NETosis and thrombosis, suggesting that NLRP3 inhibition may also hold potential for mitigating thrombotic events. Therefore, future preclinical and clinical studies aimed at identifying and validating NLRP3 inhibition as a novel therapeutic intervention for thrombotic disorders are imperative.

Platelet mitochondria: the mighty few

PURPOSE OF REVIEW

Platelet mitochondrial dysfunction is both caused by, as well as a source of oxidative stress. Oxidative stress is a key hallmark of metabolic disorders such as dyslipidemia and diabetes, which are known to have higher risks for thrombotic complications.

RECENT FINDINGS

Increasing evidence supports a critical role for platelet mitochondria beyond energy production and apoptosis. Mitochondria are key regulators of reactive oxygen species and procoagulant platelets, which both contribute to pathological thrombosis. Studies targeting platelet mitochondrial pathways have reported promising results suggesting antithrombotic effects with limited impact on hemostasis in animal models.

SUMMARY

Targeting platelet mitochondria holds promise for the reduction of thrombotic complications in patients with metabolic disorders. Future studies should aim at validating these preclinical findings and translate them to the clinic.

Redefining Autoimmune Disorders' Pathoetiology: Implications for Mood and Psychotic Disorders' Association with Neurodegenerative and Classical Autoimmune Disorders

Although previously restricted to a limited number of medical conditions, there is a growing appreciation that 'autoimmune' (or immune-mediated) processes are important aspects of a wide array of diverse medical conditions, including cancers, neurodegenerative diseases and psychiatric disorders. All of these classes of medical conditions are associated with alterations in mitochondrial function across an array of diverse cell types. Accumulating data indicate the presence of the mitochondrial melatonergic pathway in possibly all body cells, with important consequences for pathways crucial in driving CD8⁺ T cell and B-cell 'autoimmune'-linked processes. Melatonin suppression coupled with the upregulation of oxidative stress suppress PTEN-induced kinase 1 (PINK1)/parkin-driven mitophagy, raising the levels of the major histocompatibility complex (MHC)-1, which underpins the chemoattraction of CD8⁺ T cells and the activation of antibody-producing B-cells. Many factors and processes closely associated with autoimmunity, including gut microbiome/permeability, circadian rhythms, aging, the aryl hydrocarbon receptor, brain-derived neurotrophic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB) all interact with the mitochondrial melatonergic pathway. A number of future research directions and novel treatment implications are indicated for this wide collection of poorly conceptualized and treated medical presentations. It is proposed that the etiology of many 'autoimmune'/'immune-mediated' disorders should be conceptualized as significantly determined by mitochondrial dysregulation, with alterations in the mitochondrial melatonergic pathway being an important aspect of these pathoetiologies.

Amyotrophic Lateral Sclerosis Pathoetiology and Pathophysiology: Roles of Astrocytes, Gut Microbiome, and Muscle Interactions via the Mitochondrial Melatonergic Pathway, with Disruption by Glyphosate-Based Herbicides

The pathoetiology and pathophysiology of motor neuron loss in amyotrophic lateral sclerosis (ALS) are still to be determined, with only a small percentage of ALS patients having a known genetic risk factor. The article looks to integrate wider bodies of data on the biological underpinnings of ALS, highlighting the integrative role of alterations in the mitochondrial melatonergic pathways and systemic factors regulating this pathway across a number of crucial hubs in ALS pathophysiology, namely glia, gut, and the muscle/neuromuscular junction. It is proposed that suppression of the mitochondrial melatonergic pathway underpins changes in muscle brain-derived neurotrophic factor, and its melatonergic pathway mimic, N-acetylserotonin, leading to a lack of metabolic trophic support at the neuromuscular junction. The attenuation of the melatonergic pathway in astrocytes prevents activation of toll-like receptor agonists-induced pro-inflammatory transcription factors, NF-kB, and yin yang 1, from having a built-in limitation on inflammatory induction that arises from their synchronized induction of melatonin release. Such maintained astrocyte activation, coupled with heightened microglia reactivity, is an important driver of motor neuron susceptibility in ALS. Two important systemic factors, gut dysbiosis/permeability and pineal melatonin mediate many of their beneficial effects via their capacity to upregulate the mitochondrial melatonergic pathway in central and systemic cells. The mitochondrial melatonergic pathway may be seen as a core aspect of cellular function, with its suppression increasing reactive oxygen species (ROS), leading to ROS-induced microRNAs, thereby altering the patterning of genes induced. It is proposed that the increased occupational risk of ALS in farmers, gardeners, and sportsmen and women is intimately linked to exposure, whilst being physically active, to the widely used glyphosate-based herbicides. This has numerous research and treatment implications.

Tumor Microenvironment and Metabolism: Role of the Mitochondrial Melatonergic Pathway in Determining Intercellular Interactions in a New Dynamic Homeostasis

There is a growing interest in the role of alterations in mitochondrial metabolism in the pathoetiology and pathophysiology of cancers, including within the array of diverse cells that can form a given tumor microenvironment. The 'exhaustion' in natural killer cells and CD8+ t cells as well as the tolerogenic nature of dendritic cells in the tumor microenvironment seems determined by variations in mitochondrial function. Recent work has highlighted the important role played by the melatonergic pathway in optimizing mitochondrial function, limiting ROS production, endogenous antioxidants upregulation and consequent impacts of mitochondrial ROS on ROS-dependent microRNAs, thereby impacting on patterned gene expression. Within the tumor microenvironment, the tumor, in a quest for survival, seeks to 'dominate' the dynamic intercellular interactions by limiting the capacity of cells to optimally function, via the regulation of their mitochondrial melatonergic pathway. One aspect of this is the tumor's upregulation of kynurenine and the activation of the aryl hydrocarbon receptor, which acts to metabolize melatonin and increase the N-acetylserotonin/melatonin ratio, with effluxed N-acetylserotonin acting as a brain-derived neurotrophic factor (BDNF) mimic via its activation of the BDNF receptor, TrkB, thereby increasing the survival and proliferation of tumors and cancer stem-like cells. This article highlights how many of the known regulators of cells in the tumor microenvironment can be downstream of the mitochondrial melatonergic pathway regulation. Future research and treatment implications are indicated.

Pharmacological Actions of 5-Hydroxyindolin-2 on Modulation of Platelet Functions and Thrombus Formation via Thromboxane A2 Inhibition and cAMP Production

Platelets play a very significant role in hemostasis while simultaneously posing a risk for the development of various cardiovascular diseases. Platelet-mediated issues can occur in blood vessels and trigger various medical problems. Therefore, controlling platelet function is important in the prevention of thrombosis. In this regard, we need to find compounds that provide potent antiplatelet activity with minimum side effects. Therefore, we examined the effect of 5-hydroxyindolin-2-one isolated from Protaetia brevitarsis larvae having antiplatelet properties and investigated different pathways that mediate the antiplatelet activity. We examined the effect of 5-hydroxyindolin-2-one (5-HI) on the regulation of phosphoproteins, thromboxane A₂ generation, and integrin αIIbβ3 action. Our data showed that human platelet aggregation was inhibited by 5-HI (75, 100, 150, 200 μM) without cytotoxicity, and it suppressed intracellular Ca²⁺ concentration through the regulation of inositol 1, 4, 5-triphosphate receptor I (Ser¹⁷⁵⁶) and extracellular signal-regulated kinase (ERK). Moreover, collagen-elevated thromboxane A₂ production and αIIbβ3 action were inhibited by 5-HI through the regulation of cytosolic phospholipase A₂ (cPLA₂), mitogen-activated protein kinase p38 (p38^MAPK), vasodilator-stimulated phosphoprotein (VASP), phosphoinositide 3-kinase (PI3K), and Akt (protein kinase B). Therefore, we suggested that 5-HI could be a potential substance for the prevention of thrombosis-mediated thrombosis.