Mitochondrial metabolism, reactive oxygen species, and macrophage function-fishing for insights

High-fat stimulation induces atrial neural remodeling by reducing NO production via the CRIF1/eNOS/P21 axi

BACKGROUND

Autonomic remodeling of the atria plays a pivotal role in the development of atrial fibrillation (AF) and exerts a substantial influence on the progression of this condition. Hyperlipidemia is a predisposing factor for AF, but its effect on atrial nerve remodeling is unclear. The primary goal of this study was to explore the possible mechanisms through which the consumption of a high-fat diet (HFD) induces remodeling of atrial nerves, and to identify novel targets for clinical intervention.

METHODS

Cell models were created in vitro by subjecting cells to palmitic acid (PA), while rat models were established by feeding them a high-fat diet. To investigate the interplay between cardiomyocytes and nerve cells in a co-culture system, we utilized Transwell cell culture plates featuring a pore size of 0.4 μm. The CCK-8 assay was employed to determine cell viability, fluorescent probe DCFH-DA and flow cytometry were utilized for measuring ROS levels, JC-1 was used to assess the mitochondrial membrane potential, the Griess method was employed to measure the nitric oxide (NO) level in the supernatant, a fluorescence-based method was used to measure ATP levels, and MitoTracker was utilized for assessing mitochondrial morphology. The expression of pertinent proteins was evaluated using western blotting (WB) and immunohistochemistry techniques. SNAP was used to treat nerve cells in order to replicate a high-NO atmosphere, and the level of nitroso was assessed using the iodoTMT reagent labeling method.

RESULTS

The study found that cardiomyocytes' mitochondrial morphology and function were impaired under high-fat stimulation, affecting nitric oxide (NO) production through the CRIF1/SIRT1/eNOS axis. In a coculture model, overexpression of eNOS in cardiomyocytes increased NO expression. Moreover, the increased Keap1 nitrosylation within neuronal cells facilitated the entry of Nrf2 into the nucleus, resulting in an augmentation of P21 transcription and a suppression of proliferation. Atrial neural remodeling occurred in the HFD rat model and was ameliorated by increasing myocardial tissue eNOS protein expression with trimetazidine (TMZ).

CONCLUSIONS

Neural remodeling is triggered by high-fat stimulation, which decreases the production of NO through the CRIF1/eNOS/P21 axis. Additionally, TMZ prevents neural remodeling and reduces the occurrence of AF by enhancing eNOS expression.

Uricase-Deficient Larval Zebrafish with Elevated Urate Levels Demonstrate Suppressed Acute Inflammatory Response to Monosodium Urate Crystals and Prolonged Crystal Persistence

Gout is caused by elevated serum urate leading to the deposition of monosodium urate (MSU) crystals that can trigger episodes of acute inflammation. Humans are sensitive to developing gout because they lack a functional urate-metabolizing enzyme called uricase/urate oxidase (encoded by the UOX gene). A hallmark of long-standing disease is tophaceous gout, characterized by the formation of tissue-damaging granuloma-like structures ('tophi') composed of densely packed MSU crystals and immune cells. Little is known about how tophi form, largely due to the lack of suitable animal models in which the host response to MSU crystals can be studied in vivo long-term. We have previously described a larval zebrafish model of acute gouty inflammation where the host response to microinjected MSU crystals can be live imaged within an intact animal. Although useful for modeling acute inflammation, crystals are rapidly cleared following a robust innate immune response, precluding analysis at later stages. Here we describe a zebrafish uox null mutant that possesses elevated urate levels at larval stages. Uricase-deficient 'hyperuricemic' larvae exhibit a suppressed acute inflammatory response to MSU crystals and prolonged in vivo crystal persistence. Imaging of crystals at later stages reveals that they form granuloma-like structures dominated by macrophages. We believe that uox^-/- larvae will provide a useful tool to explore the transition from acute gouty inflammation to tophus formation, one of the remaining mysteries of gout pathogenesis.

Impact of Lung Microbiota on COPD

There is a fine balance in maintaining healthy microbiota composition, and its alterations due to genetic, lifestyle, and environmental factors can lead to the onset of respiratory dysfunctions such as chronic obstructive pulmonary disease (COPD). The relationship between lung microbiota and COPD is currently under study. Little is known about the role of the microbiota in patients with stable or exacerbated COPD. Inflammation in COPD disorders appears to be characterised by dysbiosis, reduced lung activity, and an imbalance between the innate and adaptive immune systems. Lung microbiota intervention could ameliorate these disorders. The microbiota’s anti-inflammatory action could be decisive in the onset of pathologies. In this review, we highlight the feedback loop between microbiota dysfunction, immune response, inflammation, and lung damage in relation to COPD status in order to encourage the development of innovative therapeutic goals for the prevention and management of this disease.

Peripheral NOD-like receptor deficient inflammatory macrophages trigger neutrophil infiltration into the brain disrupting daytime locomotion

Inflammation is known to disrupt normal behavior, yet the underlying neuroimmune interactions remain elusive. Here, we investigated whether inappropriate macrophage-evoked inflammation alters CNS control of daily-life animal locomotion using a set of zebrafish mutants selected for specific macrophage dysfunction and microglia deficiency. Large-scale genetic and computational analyses revealed that NOD-like receptor nlrc3l mutants are capable of normal motility and visuomotor response, but preferentially swim less in the daytime, suggesting possible low motivation rather than physical impairment. Examining their brain activities and structures implicates impaired dopaminergic descending circuits, where neutrophils abnormally infiltrate. Furthermore, neutrophil depletion recovered daytime locomotion. Restoring wild-type macrophages reversed behavioral and neutrophil aberrations, while three other microglia-lacking mutants failed to phenocopy nlrc3l mutants. Overall, we reveal how peripheral inflammatory macrophages with elevated pro-inflammatory cues (including il1β, tnfα, cxcl8a) in the absence of microglia co-opt neutrophils to infiltrate the brain, thereby potentially enabling local circuitry modulation affecting daytime locomotion.

Pinocembrin ameliorates acute liver failure via activating the Sirt1/PPARα pathway in vitro and in vivo

Acute liver failure (ALF) is a life-threatening disease and affects multiple organ systems. Pro-inflammatory factors derived from macrophage plays a key role in septicemia. Pinocembrin is a natural favonoid compound, which can be extracted from honey, propolis and several other plants. Recent investigations demonstrate that Pinocembrin has a variety of pharmacological activities, including anti-inflammatory and antioxidant. To investigate the effects of Pinocembrin on ALF, we explored its possible molecular mechanisms through the experiments in vivo and in vitro. Pre-treatment with Pinocembrin attenuated LPS-induced hepatocyte dysfunction and reduced levels of pro-inflammatory factors and macrophages infiltration. Pinocembrin inhibited the hepatocyte apoptosis and pro-inflammatory reaction of peritoneal macrophages by reducing reactive oxygen species (ROS) via the Sirt1/PPARα signaling pathway. Our study suggests that Pinocembrin might represent a novel therapeutic drug and offers a new method for the treatment of ALF.

Mitochondrial connections with immune system in Zebrafish

Mitochondria are organelles commonly associated with adenosine triphosphate (ATP) formation through the oxidative phosphorylation (OXPHOS) process. However, mitochondria are also responsible for functions such as calcium homeostasis, apoptosis, autophagy, and production of reactive oxygen species (ROS) that, in conjunction, can lead to different cell fate decisions. Mitochondrial morphology changes rely on nutrients' availability and the bioenergetics demands of the cells, in a process known as mitochondrial dynamics, which includes both fusion and fission. This organelle senses the microenvironment and can modify the cells to either a pro or anti-inflammatory profile. The zebrafish has been increasingly used to research mitochondrial dynamics and its connection with the immune system since the pathways and molecules involved in these processes are conserved on this fish. Several genetic tools and technologies are currently available to analyze the behavior of mitochondria in zebrafish. However, even though zebrafish presents several similar processes known in mammals, the effect of the mitochondria in the immune system has not been so broadly studied in this model. In this review, we summarize the current knowledge in zebrafish studies regarding mitochondrial function and immuno metabolism.

Cardiomyopathic mutations in essential light chain reveal mechanisms regulating the super relaxed state of myosin

In this study, we assessed the super relaxed (SRX) state of myosin and sarcomeric protein phosphorylation in two pathological models of cardiomyopathy and in a near-physiological model of cardiac hypertrophy. The cardiomyopathy models differ in disease progression and severity and express the hypertrophic (HCM-A57G) or restrictive (RCM-E143K) mutations in the human ventricular myosin essential light chain (ELC), which is encoded by the MYL3 gene. Their effects were compared with near-physiological heart remodeling, represented by the N-terminally truncated ELC (Δ43 ELC mice), and with nonmutated human ventricular WT-ELC mice. The HCM-A57G and RCM-E143K mutations had antagonistic effects on the ATP-dependent myosin energetic states, with HCM-A57G cross-bridges fostering the disordered relaxed (DRX) state and the RCM-E143K model favoring the energy-conserving SRX state. The HCM-A57G model promoted the switch from the SRX to DRX state and showed an ∼40% increase in myosin regulatory light chain (RLC) phosphorylation compared with the RLC of normal WT-ELC myocardium. On the contrary, the RCM-E143K–associated stabilization of the SRX state was accompanied by an approximately twofold lower level of myosin RLC phosphorylation compared with the RLC of WT-ELC. Upregulation of RLC phosphorylation was also observed in Δ43 versus WT-ELC hearts, and the Δ43 myosin favored the energy-saving SRX conformation. The two disease variants also differently affected the duration of force transients, with shorter (HCM-A57G) or longer (RCM-E143K) transients measured in electrically stimulated papillary muscles from these pathological models, while no changes were displayed by Δ43 fibers. We propose that the N terminus of ELC (N-ELC), which is missing in the hearts of Δ43 mice, works as an energetic switch promoting the SRX-to-DRX transition and contributing to the regulation of myosin RLC phosphorylation in full-length ELC mice by facilitating or sterically blocking RLC phosphorylation in HCM-A57G and RCM-E143K hearts, respectively.

Mitochondria and Pharmacologic Cardiac Conditioning-At the Heart of Ischemic Injury

Pharmacologic cardiac conditioning increases the intrinsic resistance against ischemia and reperfusion (I/R) injury. The cardiac conditioning response is mediated via complex signaling networks. These networks have been an intriguing research field for decades, largely advancing our knowledge on cardiac signaling beyond the conditioning response. The centerpieces of this system are the mitochondria, a dynamic organelle, almost acting as a cell within the cell. Mitochondria comprise a plethora of functions at the crossroads of cell death or survival. These include the maintenance of aerobic ATP production and redox signaling, closely entwined with mitochondrial calcium handling and mitochondrial permeability transition. Moreover, mitochondria host pathways of programmed cell death impact the inflammatory response and contain their own mechanisms of fusion and fission (division). These act as quality control mechanisms in cellular ageing, release of pro-apoptotic factors and mitophagy. Furthermore, recently identified mechanisms of mitochondrial regeneration can increase the capacity for oxidative phosphorylation, decrease oxidative stress and might help to beneficially impact myocardial remodeling, as well as invigorate the heart against subsequent ischemic insults. The current review highlights different pathways and unresolved questions surrounding mitochondria in myocardial I/R injury and pharmacological cardiac conditioning.

The Role of Posttranslational Modification and Mitochondrial Quality Control in Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death in the world. The mechanism behind CVDs has been studied for decades; however, the pathogenesis is still controversial. Mitochondrial homeostasis plays an essential role in maintaining the normal function of the cardiovascular system. The alterations of any protein function in mitochondria may induce abnormal mitochondrial quality control and unexpected mitochondrial dysfunction, leading to CVDs. Posttranslational modifications (PTMs) affect protein function by reversibly changing their conformation. This review summarizes how common and novel PTMs influence the development of CVDs by regulating mitochondrial quality control. It provides not only ideas for future research on the mechanism of some types of CVDs but also ideas for CVD treatments with therapeutic potential.

Extensive Simulated Diving Aggravates Endothelial Dysfunction in Male Pro-atherosclerotic ApoE Knockout Rats

Introduction

The average age of the diving population is rising, and the risk of atherosclerosis and cardiovascular disease in divers are accordingly increasing. It is an open question whether this risk is altered by diving per se. In this study, we examined the effect of 7-weeks simulated diving on endothelial function and mitochondrial respiration in atherosclerosis-prone rats.

Methods

Twenty-four male ApoE knockout (KO) rats (9-weeks-old) were fed a Western diet for 8 weeks before 12 rats were exposed to simulated heliox dry-diving in a pressure chamber (600 kPa for 60 min, decompression of 50 kPa/min). The rats were dived twice-weekly for 7 weeks, resulting in a total of 14 dives. The remaining 12 non-diving rats served as controls. Endothelial function of the pulmonary and mesenteric arteries was examined in vitro using an isometric myograph. Mitochondrial respiration in cardiac muscle tissues was measured using high-resolution respirometry.

Results and Conclusion

Both ApoE KO diving and non-diving rats showed changes in endothelial function at the end of the intervention, but the extent of these changes was larger in the diving group. Altered nitric oxide signaling was primarily involved in these changes. Mitochondrial respiration was unaltered. In this pro-atherosclerotic rat model of cardiovascular changes, extensive diving appeared to aggravate endothelial dysfunction rather than promote adaptation to oxidative stress.

T-2 Toxin-Induced Oxidative Stress Leads to Imbalance of Mitochondrial Fission and Fusion to Activate Cellular Apoptosis in the Human Liver 7702 Cell Line

T-2 toxin, as a highly toxic mycotoxin to humans and animals, induces oxidative stress and apoptosis in various cells and tissues. Apoptosis and mitochondrial fusion/fission are two tightly interconnected processes that are crucial for maintaining physiological homeostasis. However, the role of mitochondrial fusion/fission in apoptosis of T-2 toxin remains unknown. Hence, we aimed to explore the putative role of mitochondrial fusion/fission on T-2 toxin induced apoptosis in normal human liver (HL-7702) cells. T-2 toxin treatment (0, 0.1, 1.0, or 10 μg/L) for 24 h caused decreased cell viability and ATP concentration and increased production of (ROS), as seen by a loss of mitochondrial membrane potential (∆Ψm) and increase in mitochondrial fragmentation. Subsequently, the mitochondrial dynamic imbalance was activated, evidenced by a dose-dependent decrease and increase in the protein expression of mitochondrial fusion (OPA1, Mfn1, and Mfn2) and fission (Drp1 and Fis1), respectively. Furthermore, the T-2 toxin promoted the release of cytochrome c from mitochondria to cytoplasm and induced cell apoptosis triggered by upregulation of Bax and Bax/Bcl-2 ratios, and further activated the caspase pathways. Taken together, these results indicate that altered mitochondrial dynamics induced by oxidative stress with T-2 toxin exposure likely contribute to mitochondrial injury and HL-7702 cell apoptosis.

Defective bacterial phagocytosis is associated with dysfunctional mitochondria in COPD macrophages

Increased reactive oxygen species (ROS) have been implicated in the pathophysiology of chronic obstructive pulmonary disease (COPD). This study examined the effect of exogenous and endogenous oxidative stress on macrophage phagocytosis in patients with COPD.Monocyte-derived macrophages (MDMs) were generated from non-smoker, smoker and COPD subjects, differentiated in either granulocyte macrophage-colony stimulating factor (G-Mφ) or macrophage-colony stimulating factor (M-Mφ). Alveolar macrophages were isolated from lung tissue or bronchoalveolar lavage fluid. Macrophages were incubated in ±200 µM H₂O₂ for 24 h, then exposed to fluorescently labelled Haemophilus influenzae or Streptococcus pneumoniae for 4 h, after which phagocytosis, mitochondrial ROS (mROS) and mitochondrial membrane potential (ΔΨm) were measured.Phagocytosis of bacteria was significantly decreased in both G-Mφ and M-Mφ from COPD patients compared with from non-smoker controls. In non-smokers and smokers, bacterial phagocytosis did not alter mROS or ΔΨm; however, in COPD, phagocytosis increased early mROS and decreased ΔΨm in both G-Mφ and M-Mφ. Exogenous oxidative stress reduced phagocytosis in non-smoker and COPD alveolar macrophages and non-smoker MDMs, associated with reduced mROS production.COPD macrophages show defective phagocytosis, which is associated with altered mitochondrial function and an inability to regulate mROS production. Targeting mitochondrial dysfunction may restore the phagocytic defect in COPD.

mTOR-Dependent Oxidative Stress Regulates oxLDL-Induced Trained Innate Immunity in Human Monocytes

Introduction: Cells of the innate immune system particularly monocytes and macrophages have been recognized as pivotal players both during the initial insult as well as the chronic phase of atherosclerosis. It has recently been shown that oxidized low-density lipoprotein (oxLDL) induces a long-term pro-inflammatory response in monocytes due to epigenetic and metabolic reprogramming, an emerging new concept called trained innate immunity. Changes in the cellular redox state are crucial events in the regulation of many physiologic functions in macrophages including transcription, differentiation and inflammatory response. Here we have analyzed the role of reactive oxygen species (ROS) in regulating this proinflammatory monocyte priming in response to oxLDL-treatment.

Methods and Results: Human monocytes were isolated and incubated with oxLDL for 24 h. After 5 days of resting, oxLDL treated cells produced significantly more inflammatory cytokines upon restimulation with the TLR2-agonist Pam3cys. Furthermore, oxLDL incubation induced persistent mTOR activation, ROS formation, HIF1α accumulation and HIF1α target gene expression, while pharmacologic mTOR inhibition or siRNA mediated inhibition of the mTORC1 subunit Raptor prevented ROS formation and proinflammatory priming. mTOR dependent ROS formation was associated with increased expression of NAPDH oxidases and necessary for the emergence of the primed phenotype as antioxidant treatment blocked oxLDL priming. Inhibition of cytosolic ROS formation could also block mTOR activation and HIF1α accumulation suggesting a positive feedback loop between mTOR and cytosolic ROS. Although mitochondrial ROS scavenging did not block HIF1α-accumulation at an early time point (24 h), it was persistently reduced on day 6. Therefore, mitochondrial ROS formation appears to occur initially downstream of the mTOR-cytoROS-HIF1α feedback loop but seems to be a crucial factor that controls the long-term activation of the mTOR-HIF1α-axis.

Conclusion: In summary, our data demonstrate that mTOR dependent ROS production controls the oxLDL-induced trained innate immunity phenotype in human monocyte derived macrophages. Pharmacologic modulation of these pathways might provide a potential approach to modulate inflammation, associated with aberrant monocyte activation, during atherosclerosis development.

Reactive oxygen species (ROS) in macrophage activation and function in diabetes

In a diabetic milieu high levels of reactive oxygen species (ROS) are induced. This contributes to the vascular complications of diabetes. Recent studies have shown that ROS formation is exacerbated in diabetic monocytes and macrophages due to a glycolytic metabolic shift. Macrophages are important players in the progression of diabetes and promote inflammation through the release of pro-inflammatory cytokines and proteases. Because ROS is an important mediator for the activation of pro-inflammatory signaling pathways, obesity and hyperglycemia-induced ROS production may favor induction of M1-like pro-inflammatory macrophages during diabetes onset and progression. ROS induces MAPK, STAT1, STAT6 and NFκB signaling, and interferes with macrophage differentiation via epigenetic (re)programming. Therefore, a comprehensive understanding of the impact of ROS on macrophage phenotype and function is needed in order to improve treatment of diabetes and its vascular complications. In the current comprehensive review, we dissect the role of ROS in macrophage polarization, and analyze how ROS production links metabolism and inflammation in diabetes and its complications. Finally, we discuss the contribution of ROS to the crosstalk between macrophages and endothelial cells in diabetic complications.

Mitochondria and cardiovascular diseases-from pathophysiology to treatment

Mitochondria are the source of cellular energy production and are present in different types of cells. However, their function is especially important for the heart due to the high demands in energy which is achieved through oxidative phosphorylation. Mitochondria form large networks which regulate metabolism and the optimal function is achieved through the balance between mitochondrial fusion and mitochondrial fission. Moreover, mitochondrial function is upon quality control via the process of mitophagy which removes the damaged organelles. Mitochondrial dysfunction is associated with the development of numerous cardiac diseases such as atherosclerosis, ischemia-reperfusion (I/R) injury, hypertension, diabetes, cardiac hypertrophy and heart failure (HF), due to the uncontrolled production of reactive oxygen species (ROS). Therefore, early control of mitochondrial dysfunction is a crucial step in the therapy of cardiac diseases. A number of anti-oxidant molecules and medications have been used but the results are inconsistent among the studies. Eventually, the aim of future research is to design molecules which selectively target mitochondrial dysfunction and restore the capacity of cellular anti-oxidant enzymes.

Priming of innate antimycobacterial immunity by heat-killed Listeria monocytogenes induces sterilizing response in the adult zebrafish tuberculosis model

Mycobacterium tuberculosis remains one of the most problematic infectious agents, owing to its highly developed mechanisms to evade host immune responses combined with the increasing emergence of antibiotic resistance. Host-directed therapies aiming to optimize immune responses to improve bacterial eradication or to limit excessive inflammation are a new strategy for the treatment of tuberculosis. In this study, we have established a zebrafish-Mycobacterium marinum natural host-pathogen model system to study induced protective immune responses in mycobacterial infection. We show that priming adult zebrafish with heat-killed Listeria monocytogenes (HKLm) at 1 day prior to M. marinum infection leads to significantly decreased mycobacterial loads in the infected zebrafish. Using rag1^−/− fish, we show that the protective immunity conferred by HKLm priming can be induced through innate immunity alone. At 24 h post-infection, HKLm priming leads to a significant increase in the expression levels of macrophage-expressed gene 1 (mpeg1), tumor necrosis factor α (tnfa) and nitric oxide synthase 2b (nos2b), whereas superoxide dismutase 2 (sod2) expression is downregulated, implying that HKLm priming increases the number of macrophages and boosts intracellular killing mechanisms. The protective effects of HKLm are abolished when the injected material is pretreated with nucleases or proteinase K. Importantly, HKLm priming significantly increases the frequency of clearance of M. marinum infection by evoking sterilizing immunity (25 vs 3.7%, P=0.0021). In this study, immune priming is successfully used to induce sterilizing immunity against mycobacterial infection. This model provides a promising new platform for elucidating the mechanisms underlying sterilizing immunity and to develop host-directed treatment or prevention strategies against tuberculosis.

This article has an associated First Person interview with the first author of the paper.

Summary: Heat-killed Listeria monocytogenes induces immune responses that lead to increased clearance of mycobacterial infection in the adult zebrafish tuberculosis model via innate immune mechanisms.

ROS homeostasis, a key determinant in liver ischemic-preconditioning

Reactive Oxygen Species (ROS) are key mediators of ischemia-reperfusion injury but also required for the induction of the stress response that limits tissue injury and underlies the protection provided by ischemic-preconditioning protocols. Liver steatosis is an important risk factor for liver transplant failure. Liver steatosis is associated with mitochondrial dysfunction and excessive mitochondrial ROS production. Studies aiming at decreasing the sensibility of the steatotic liver to ischemia-reperfusion injury using pre-conditioning protocols, have shown that the steatotic liver has a reduced capacity to respond to these protocols. Recent studies indicate that these effects are related to a reduced capacity of the steatotic liver to respond to elevated ROS levels following reperfusion by inducing a compensatory response. This failure to respond to ROS is associated with reduced levels of antioxidants, mitochondrial damage, hepatocyte cell death, activation of the immune system and induction of pro-fibrotic mediators.

Innate immune cells and bacterial infection in zebrafish

The physical attributes of the zebrafish, including optical transparency during embryogenesis, large clutch sizes, external development, and rapid organogenesis were features that initially attracted developmental biologists to use this vertebrate as an experimental model system. With the progressive development of an extensive genetic "tool kit" and an ever-growing number of transgenic reporter lines, the zebrafish model has evolved into an informative system in which to mimic and study aspects of human disease, including those associated with bacterial infections. This chapter provides detailed protocols for microinjection of bacterial strains into zebrafish larvae and subsequent experiments to investigate single-larva bacterial burdens, live imaging of specific neutrophil and macrophage bactericidal functions, and how these protocols may be applied to drug discovery approaches to uncover novel immunomodulatory drugs.

MicroRNA regulation of macrophages in human pathologies

Macrophages play a crucial role in the innate immune system and contribute to a broad spectrum of pathologies, like in the defence against infectious agents, in inflammation resolution, and wound repair. In the past several years, microRNAs (miRNAs) have been demonstrated to play important roles in immune diseases by regulating macrophage functions. In this review, we will summarize the role of miRNAs in the differentiation of monocytes into macrophages, in the classical and alternative activation of macrophages, and in the regulation of phagocytosis and apoptosis. Notably, miRNAs preferentially target genes related to the cellular cholesterol metabolism, which is of key importance for the inflammatory activation and phagocytic activity of macrophages. miRNAs functionally link various mechanisms involved in macrophage activation and contribute to initiation and resolution of inflammation. miRNAs represent promising diagnostic and therapeutic targets in different conditions, such as infectious diseases, atherosclerosis, and cancer.

Mitochondrial respiratory dysfunctions of blood mononuclear cells link with cardiac disturbance in patients with early-stage heart failure

Patients with cardiometabolic risk factors and asymptomatic cardiac hypertrophy are hallmarks of early-stage heart failure (HF). We hypothesized that mitochondrial respiratory dysfunctions of peripheral blood mononuclear cells (PBMCs) may be associated with inflammation and oxidative stress in early-stage HF patients complicated with cardiometabolic risk factors. Totally 49 subjects were enrolled with 25 early-stage HF patients (stages A and B) having cardiac hypertrophy and dysfunction and 24 healthy controls. It showed that excessive inflammation and reduced antioxidant capacity were closely associated with cardiac abnormalities in early-stage HF patients. Furthermore, the values of mitochondrial respiratory functional parameters R, CIOXPHOS, CIIOXPHOS, CI+IIOXPHOS, CI+IIETS and CIIETS were significantly lowered in early-stage HF patients. Interestingly, these respiratory parameters were correlated with inflammation and antioxidant capacity in participants. Finally, cardiometabolic risk factors such as salt intake and blood pressure were related to the mitochondrial respiratory dysfunctions, which were further validated by in vitro experiments. Our study indicated that cardiometabolic risk factor-mediated mitochondrial respiratory dysfunctions of PBMCs link with the cellular inflammation / oxidative stress and cardiac disturbance in early-stage HF.

The role of physiological elements in the future therapies of rheumatoid arthritis. II. The relevance of energy redistribution in the process of chronic inflammation

The reasons for development of chronic inflammation are complex and not fully understood. One of the factors affecting the prolongation of inflammation is changes in cell metabolism, occurring at the center of the inflammatory process. In chronic inflammation there is an imbalance between the processes of storage and consumption of energy reserves. Hypoxia that is a consequence of edema results in transition of white blood cells to anaerobic metabolism. Neutrophils, lymphocytes and macrophages produce active oxygen metabolites which on one hand facilitate the elimination of pathogens, and on the other hand, can cause damage to healthy cells located in the inflamed tissue. In this paper, we discuss the importance of disturbed redistribution of energy as one of the main reasons for transformation of the acute inflammatory process into the chronic one.