Inhibiting nucleolin reduces inflammation induced by mitochondrial DNA in cardiomyocytes exposed to hypoxia and reoxygenation

Inhibition of mtDNA-PRRs pathway-mediated sterile inflammation by astragalus polysaccharide protects against transport stress-induced cardiac injury in chicks

Transport stress (TS) not only weakens poultry performance but also affects animal welfare. Additionally, TS can evoke cardiac damage by triggering sterile inflammation in chicks, but the underlying mechanism is not fully understood. Here, we aimed to elucidate how TS induces sterile inflammation and heart injury and to clarify the antagonism effect of astragalus polysaccharides (APS). We randomly divided 60 chicks (one-day-old female) into 5 groups (n = 12): Control_0h (Con_0h) group (chicks were slaughtered at initiation), Control group (stress-free control), TS group (simulated TS exposure for 8 h), TS plus water (TS+W) group, and TS plus APS (TS+APS) group. Before simulation transport, the chicks of TS+W and TS+APS groups were, respectively, dietary with 100 μL of water or APS (250 μg/mL). H&E staining was employed for cardiac histopathological observation. ELISA assay was used to measure oxidative stress marker levels (GSH, GPX, GST, and MDA). A commercial kit was used to isolate the mitochondrial portion, and qRT-PCR was employed to measure the mitochondrial DNA (mtDNA) levels. Furthermore, we evaluated the activity of mtDNA-mediated NF-κB, NLRP3 inflammasome, and cGAS-STING inflammatory pathways and the expression of downstream inflammatory factors by Western Blotting or qRT-PCR. Our findings revealed that APS notably relieved TS-induced myocardial histopathological lesions and infiltrations. Likewise, the decrease in proinflammatory factors (TNF-α, IL-1β, and IL-6) and IFN-β by APS further supported this result. Meanwhile, TS caused severe oxidative stress in the chick heart, as evidenced by decreased antioxidant enzymes and increased MDA. Importantly, APS prevented mtDNA stress and leakage by reducing oxidative stress. Interestingly, TS-induced mtDNA leakage caused a series of inflammation events via mtDNA-PRRs pathways, including TLR21-NF-κB, NLRP3 inflammasome, and cGAS-STING signaling. Encouragingly, all these adverse changes related to inflammation events induced by mtDNA-PRRs activation were all relieved by APS treatment. In summary, our findings provide the first evidence that inhibition of mtDNA-PRRs pathway-mediated sterile inflammation by APS could protect against TS-induced cardiac damage in chicks.

When Our Best Friend Becomes Our Worst Enemy: The Mitochondrion in Trauma, Surgery, and Critical Illness

Common for major surgery, multitrauma, sepsis, and critical illness, is a whole-body inflammation. Tissue injury is able to trigger a generalized inflammatory reaction. Cell death causes release of endogenous structures termed damage associated molecular patterns (DAMPs) that initiate a sterile inflammation. Mitochondria are evolutionary endosymbionts originating from bacteria, containing molecular patterns similar to bacteria. These molecular patterns are termed mitochondrial DAMPs (mDAMPs). Mitochondrial debris released into the extracellular space or into the circulation is immunogenic and damaging secondary to activation of the innate immune system. In the circulation, released mDAMPS are either free or exist in extracellular vesicles, being able to act on every organ and cell in the body. However, the role of mDAMPs in trauma and critical care is not fully clarified. There is a complete lack of knowledge how they may be counteracted in patients. Among mDAMPs are mitochondrial DNA, cardiolipin, N-formyl peptides, cytochrome C, adenosine triphosphate, reactive oxygen species, succinate, and mitochondrial transcription factor A. In this overview, we present the different mDAMPs, their function, release, targets, and inflammatory potential. In light of present knowledge, the role of mDAMPs in the pathophysiology of major surgery and trauma as well as sepsis, and critical care is discussed.

RGS6 drives cardiomyocyte death following nucleolar stress by suppressing Nucleolin/miRNA-21

BACKGROUND

Prior evidence demonstrated that Regulator of G protein Signaling 6 (RGS6) translocates to the nucleolus in response to cytotoxic stress though the functional significance of this phenomenon remains unknown.

METHODS

Utilizing in vivo gene manipulations in mice, primary murine cardiac cells, human cell lines and human patient samples we dissect the participation of a RGS6-nucleolin complex in chemotherapy-dependent cardiotoxicity.

RESULTS

Here we demonstrate that RGS6 binds to a key nucleolar protein, Nucleolin, and controls its expression and activity in cardiomyocytes. In the human myocyte AC-16 cell line, induced pluripotent stem cell derived cardiomyocytes, primary murine cardiomyocytes, and the intact murine myocardium tuning RGS6 levels via overexpression or knockdown resulted in diametrically opposed impacts on Nucleolin mRNA, protein, and phosphorylation.RGS6 depletion provided marked protection against nucleolar stress-mediated cell death in vitro, and, conversely, RGS6 overexpression suppressed ribosomal RNA production, a key output of the nucleolus, and triggered death of myocytes. Importantly, overexpression of either Nucleolin or Nucleolin effector miRNA-21 counteracted the pro-apoptotic effects of RGS6. In both human and murine heart tissue, exposure to the genotoxic stressor doxorubicin was associated with an increase in the ratio of RGS6/Nucleolin. Preventing RGS6 induction via introduction of RGS6-directed shRNA via intracardiac injection proved cardioprotective in mice and was accompanied by restored Nucleolin/miRNA-21 expression, decreased nucleolar stress, and decreased expression of pro-apoptotic, hypertrophy, and oxidative stress markers in heart.

CONCLUSION

Together, these data implicate RGS6 as a driver of nucleolar stress-dependent cell death in cardiomyocytes via its ability to modulate Nucleolin. This work represents the first demonstration of a functional role for an RGS protein in the nucleolus and identifies the RGS6/Nucleolin interaction as a possible new therapeutic target in the prevention of cardiotoxicity.

Targeting nucleolin improves sensitivity to chemotherapy in acute lymphoblastic leukemia

PURPOSE

Most patients with acute lymphoblastic leukemia (ALL) are treated with chemotherapy as primary care. Although the treatment response is usually positive, resistance and relapse often occur via unknown mechanisms. The purpose of this study was to identify factors associated with chemotherapy resistance in ALL. Here, we present clinical and experimental evidence that overexpression of nucleolin (NCL), a multifunctional nucleolar protein, is linked to drug resistance in ALL.

METHODS

NCL mRNA and protein levels were compared between cell lines and patient samples using qRT-PCR and immunoblotting. NCL mRNA levels were compared between patients of different disease stages from our clinic patients' specimens and publicly available ALL patient datasets. Cells and patient-derived xenograft mouse experiments were performed to assess the effect of NCL inhibition on ALL chemotherapy effectiveness.

RESULTS

Analysis of patient specimens, and publicly available RNA-sequencing datasets revealed a strong correlation between the abundance of NCL and disease relapse or poor survival in B-ALL. Altering NCL expression results in changes in drug sensitivity in ALL cell lines. High levels of NCL upregulated components of the ATP-binding cassette transporters via activation of the ERK pathway, resulting in a decrease in drug accumulation inside the cells. Targeting NCL with AS1411, an NCL-binding oligonucleotide aptamer, significantly increased the sensitivity of ALL cell lines and cells/patient-derived ALL xenograft mice to chemotherapeutic drugs and prolonged mouse survival.

CONCLUSION

Our results highlight NCL as a prognostic marker in B-ALL and a potential therapeutic target to combat chemotherapy resistance in ALL.

Anti-nucleolin aptamer, iSN04, inhibits the inflammatory responses in C2C12 myoblasts by modulating the β-catenin/NF-κB signaling pathway

A myogenetic oligodeoxynucleotide, iSN04, is the 18-base single-stranded DNA that acts as an anti-nucleolin aptamer. iSN04 has been reported to restore myogenic differentiation by suppressing inflammatory responses in myoblasts isolated from patients with diabetes or healthy myoblasts exposed to cancer-releasing factors. Thus, iSN04 is expected to be a nucleic acid drug for the muscle wasting associated with chronic diseases. The present study investigated the anti-inflammatory mechanism of iSN04 in the murine myoblast cell line C2C12. Tumor necrosis factor-α (TNF-α) or Toll-like receptor (TLR) ligands (Pam₃CSK₄ and FSL-1) induced nuclear translocation and transcriptional activity of nuclear factor-κB (NF-κB), resulting in upregulated expression of TNF-α and interleukin-6. Pre-treatment with iSN04 significantly suppressed these inflammatory responses by inhibiting the nuclear accumulation of β-catenin induced by TNF-α or TLR ligands. These results demonstrate that antagonizing nucleolin with iSN04 downregulates the inflammatory effect mediated by the β-catenin/NF-κB signaling pathway in C2C12 cells. In addition, the anti-inflammatory effects of iSN04 were also observed in the rat smooth muscle cell line A10 and the murine adipocyte-like fibroblast cell line 3T3-L1, suggesting that iSN04 may be useful in preventing inflammation induced by metabolic disorders.

Mitochondria-derived damage-associated molecular patterns and inflammation in the ischemic-reperfused heart

Cardiac cell death after myocardial infarction release endogenous structures termed damage-associated molecular patterns (DAMPs) that trigger the innate immune system and initiate a sterile inflammation in the myocardium. Cardiomyocytes are energy demanding cells and 30% of their volume are mitochondria. Mitochondria are evolutionary endosymbionts originating from bacteria containing molecular patterns similar to bacteria, termed mitochondrial DAMPs (mDAMPs). Consequently, mitochondrial debris may be particularly immunogenic and damaging. However, the role of mDAMPs in myocardial infarction is not clarified. Identifying the most harmful mDAMPs and inhibiting their early inflammatory signaling may reduce infarct size and the risk of developing post-infarct heart failure. The focus of this review is the role of mDAMPs in the immediate pro-inflammatory phase after myocardial infarction before arrival of immune cells in the myocardium. We discuss different mDAMPs, their role in physiology and present knowledge regarding their role in the inflammatory response of acute myocardial infarction.

Toll-like receptor 9 signaling after myocardial infarction: Role of p66ShcA adaptor protein

During myocardial infarction, cellular debris is released, causing a sterile inflammation via pattern recognition receptors. These reactions amplify damage and promotes secondary heart failure. The pattern recognition receptor, Toll-like receptor 9 (TLR9) detects immunogenic fragments of endogenous DNA, inducing inflammation by NFκB. The p66ShcA adaptor protein plays an important role in both ischemic myocardial damage and immune responses. We hypothesized that p66ShcA adaptor protein promotes DNA-sensing signaling via the TLR9 pathway after myocardial infarction. TLR9 protein expression increased in cardiac tissue from patients with end-stage heart failure due to ischemic heart disease. Myocardial ischemia in mice in vivo induced gene expression of key TLR9 pathway proteins (MyD88 and Unc93b1). In this model, a functional link between TLR9 and p66ShcA was revealed as; (i) ischemia-induced upregulation of TLR9 protein was abrogated in myocardium of p66ShcA knockout mice; (ii) when p66ShcA was overexpressed in NFkB reporter cells stably expressing TLR9, NFkB-activation increased during stimulation with the TLR9 agonist CpG B; (iii) in cardiac fibroblasts, p66ShcA overexpression caused TLR9 upregulation. Co-immunoprecipitation showed that ShcA proteins and TLR9 may be found in the same protein complex, which was dissipated upon TLR9 stimulation in vivo. A proximity assay confirmed the co-localization of TLR9 and ShcA proteins. The systemic immune response after myocardial ischemia was dampened in p66ShcA knockout mice as interleukin-4, -17 and -22 expression in mononuclear cells isolated from spleens was reduced. In conclusion, p66ShcA adaptor may be an interaction partner and a regulator of the TLR9 pathway post-infarction.

Changes in Nucleolin Expression during Malignant Transformation Leading to Ovarian High-Grade Serous Carcinoma

OBJECTIVE

Ovarian high-grade serous carcinoma (HGSC) is a fatal malignancy of women. Alterations in the expression of nuclear proteins are early steps in malignant transformation; nucleolin is one such protein. Changes in nucleolin expression and circulatory levels during ovarian HGSC development are unknown. The study goal was to determine if tissue and circulatory levels of nucleolin change in response to malignant transformation leading to ovarian HGSC.

METHODS

Sera, ovaries, and BRCA+ fimbria from healthy subjects, and sera and tumor tissues from patients (n = 10 each), and healthy hens and hens with HGSC were examined in exploratory and prospective studies for nucleolin expression by immunohistochemistry, immunoblotting, gene expression, and immunoassay, and analyzed by analysis of variance (ANOVA).

RESULTS

Compared with normal, nucleolin expression was higher in patients and hens with ovarian HGSC and in women with a risk of HGSC (P < 0.05). Compared with normal (1400 + 105 pg/mL, n = 8), serum nucleolin levels were 1.5 and 1.7-fold higher in patients with early- (n = 5) and late-stage (n = 5) HGSC, respectively. Additionally, serum nucleolin levels increased significantly (P < 0.05) prior to the formation of detectable masses.

CONCLUSION

This pilot study concluded that tissue and serum levels of nucleolin increase in association with malignant changes in ovaries and fimbriae leading to ovarian HGSC.

Nucleolar stress: Friend or foe in cardiac function?

Studies in the past decades have uncovered an emerging role of the nucleolus in stress response and human disease progression. The disruption of ribosome biogenesis in the nucleolus causes aberrant nucleolar architecture and function, termed nucleolar stress, to initiate stress-responsive pathways via nucleolar release sequestration of various proteins. While data obtained from both clinical and basic investigations have faithfully demonstrated an involvement of nucleolar stress in the pathogenesis of cardiomyopathy, much remains unclear regarding its precise role in the progression of cardiac diseases. On the one hand, the initiation of nucleolar stress following acute myocardial damage leads to the upregulation of various cardioprotective nucleolar proteins, including nucleostemin (NS), nucleophosmin (NPM) and nucleolin (NCL). As a result, nucleolar stress plays an important role in facilitating the survival and repair of cardiomyocytes. On the other hand, abnormalities in nucleolar architecture and function are correlated with the deterioration of cardiac diseases. Notably, the cardiomyocytes of advanced ischemic and dilated cardiomyopathy display impaired silver-stained nucleolar organiser regions (AgNORs) and enlarged nucleoli, resembling the characteristics of tissue aging. Collectively, nucleolar abnormalities are critically involved in the development of cardiac diseases.

Upregulation of FAM129B protects cardiomyocytes from hypoxia/reoxygenation-induced injury by inhibiting apoptosis, oxidative stress, and inflammatory response via enhancing Nrf2/ARE activation

Family with sequence similarity 129, member B (FAM129B) has been identified as a novel cytoprotective protein that facilitates the survival of detrimentally stimulated cells. However, whether FAM129B is involved in regulating cardiomyocyte survival after myocardial ischemia-reperfusion injury is unknown. The goal of this work was to evaluate the potential role of FAM129B in regulating hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury in vitro. We demonstrated that exposure to H/R markedly downregulated the expression of FAM129B in cardiomyocytes. Functional experiments revealed that the upregulation of FAM129B improved H/R-exposed cardiomyocyte viability, and ameliorated H/R-induced cardiomyocyte apoptosis, the generation of reactive oxygen species (ROS), and pro-inflammatory cytokine release. The upregulation of FAM129B significantly increased the nuclear expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), and reinforced Nrf2/antioxidant response element (ARE) activation in H/R-exposed cardiomyocytes. Moreover, FAM129B modulates Nrf2/ARE signaling in a Kelchlike ECH-associated protein 1-dependent manner. Notably, the inhibition of Nrf2 significantly blocked FAM129B-overexpression-induced cardioprotective effects in H/R-exposed cardiomyocytes. In summary, the findings of our work demonstrate that the upregulation of FAM129B ameliorates H/R-induced cardiomyocyte injury via enhancing Nrf2/ARE activation. Thus, our study indicates that FAM129B may play a role in myocardial ischemia-reperfusion injury and has the potential to be used as a cardioprotective target.

Protective effects of cannabidiol on the membrane proteins of skin keratinocytes exposed to hydrogen peroxide via participation in the proteostasis network

Hydrogen peroxide (H₂O₂) is widely used in clinical practice due to its antiseptic properties and its ability to heal wounds. However, due to its involvement in the formation of ROS, H₂O₂ causes several side effects, including disorders of the metabolism of skin cells and the development of chronic inflammation mediated by oxidative stress. Therefore, this study evaluated the effects of cannabidiol (CBD), a phytocannabinoid known for its antioxidant and anti-inflammatory properties, on the proteome of keratinocyte membranes exposed to H₂O₂. Overall, the hydrogen peroxide caused the levels of several proteins to increase, while the treatment with CBD prevented these changes. Analysis of the protein-protein interaction network showed that the significant changes mainly involved proteins with important roles in the proteasomal activity, protein folding processes (regulatory subunit of the proteasome 26S 6A, beta proteasome subunit type 1, chaperonin 60 kDa), protein biosynthesis (40S ribosomal proteins S16, S2 and ubiquitin-S27a), regulation of the redox balance (carbonyl reductase [NADPH] 1 and NAD(P)H [quinone] 1 dehydrogenase) and cell survival (14-3-3 theta protein). Additionally, CBD reduced the total amount of MDA, 4-HNE and 4-ONE-protein adducts. Therefore, we conclude that CBD partially prevents the changes induced by hydrogen peroxide by reducing oxidative stress and maintaining proteostasis networks. Moreover, our results indicate that combination therapy with CBD may bring a promising approach in the clinical use of hydrogen peroxide by preventing its pro-oxidative and pro-inflammatory effect through potential participation of CBD in membrane mediated molecular signaling.

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CBD prevents H₂O₂-induced changes in keratinocytes membrane proteomic profile.

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Protective effect of CBD could be mediated by alterations in proteostasis network.

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CBD promotes antioxidative and pro-survival cellular response.

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CBD reduces formation of lipid peroxidation products-protein adducts.

NETosis as a Pathogenic Factor for Heart Failure

Heart failure threatens the lives of patients and reduces their quality of life. Heart failure, especially heart failure with preserved ejection fraction, is closely related to systemic and local cardiac persistent chronic low-grade aseptic inflammation, microvascular damage characterized by endothelial dysfunction, oxidative stress, myocardial remodeling, and fibrosis. However, the initiation and development of persistent chronic low-grade aseptic inflammation is unexplored. Oxidative stress-mediated neutrophil extracellular traps (NETs) are the main immune defense mechanism against external bacterial infections. Furthermore, NETs play important roles in noninfectious diseases. After the onset of myocardial infarction, atrial fibrillation, or myocarditis, neutrophils infiltrate the damaged tissue and aggravate inflammation. In tissue injury, damage-related molecular patterns (DAMPs) may induce pattern recognition receptors (PRRs) to cause NETs, but whether NETs are directly involved in the pathogenesis and development of heart failure and the mechanism is still unclear. In this review, we analyzed the markers of heart failure and heart failure-related diseases and comorbidities, such as mitochondrial DNA, high mobility box group box 1, fibronectin extra domain A, and galectin-3, to explore their role in inducing NETs and to investigate the mechanism of PRRs, such as Toll-like receptors, receptor for advanced glycation end products, cGAS-STING, and C-X-C motif chemokine receptor 2, in activating NETosis. Furthermore, we discussed oxidative stress, especially the possibility that imbalance of thiol redox and MPO-derived HOCl promotes the production of 2-chlorofatty acid and induces NETosis, and analyzed the possibility of NETs triggering coronary microvascular thrombosis. In some heart diseases, the deletion or blocking of neutrophil-specific myeloperoxidase and peptidylarginine deiminase 4 has shown effectiveness. According to the results of current pharmacological studies, MPO and PAD4 inhibitors are effective at least for myocardial infarction, atherosclerosis, and certain autoimmune diseases, whose deterioration can lead to heart failure. This is essential for understanding NETosis as a therapeutic factor of heart failure and the related new pathophysiology and therapeutics of heart failure.

Tissue-level inflammation and ventricular remodeling in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common cardiac condition caused primarily by sarcomeric protein mutations with several distinct phenotypes, ranging from asymmetric septal hypertrophy, either with or without left ventricular outflow tract obstruction, to moderate left ventricular dilation with or without apical aneurysm formation and marked, end-stage dilation with refractory heart failure. Sudden cardiac death can occur at any stage. The phenotypic variability observed in HCM is the end-result of many factors, including pre-load, after-load, wall stress and myocardial ischemia stemming from microvascular dysfunction and thrombosis; however, tissue level inflammation to include leukocyte-derived extracellular traps consisting of chromatin and histones, apoptosis, proliferation of matrix proteins and impaired or dysfunctional regulatory pathways contribute as well. Our current understanding of the pathobiology, developmental stages, transition from hypertrophy to dilation and natural history of HCM with emphasis on the role of tissue-level inflammation in myocardial fibrosis and ventricular remodeling is summarized.

Molecular Basis of Inflammation in the Pathogenesis of Cardiomyopathies

Cardiomyopathies (CMPs) represent a diverse group of heart muscle diseases, grouped into specific morphological and functional phenotypes. CMPs are associated with mutations in sarcomeric and non-sarcomeric genes, with several suspected epigenetic and environmental mechanisms involved in determining penetrance and expressivity. The understanding of the underlying molecular mechanisms of myocardial diseases is fundamental to achieving a proper management and treatment of these disorders. Among these, inflammation seems to play an important role in the pathogenesis of CMPs. The aim of the present study is to review the current knowledge on the role of inflammation and the immune system activation in the pathogenesis of CMPs and to identify potential molecular targets for a tailored anti-inflammatory treatment.

CpG-ODN-mediated TLR9 innate immune signalling and calcium dyshomeostasis converge on the NFκB inhibitory protein IκBβ to drive IL1α and IL1β expression

Sterile inflammation contributes to many pathological states associated with mitochondrial injury. Mitochondrial injury disrupts calcium homeostasis and results in the release of CpG-rich mitochondrial DNA. The role of CpG-stimulated TLR9 innate immune signalling and sterile inflammation is well studied; however, how calcium dyshomeostasis affects this signalling is unknown. Therefore, we interrogated the relationship beτween intracellular calcium and CpG-induced TLR9 signalling in murine macrophages. We found that CpG-ODN-induced NFκB-dependent IL1α and IL1β expression was significantly attenuated by both calcium chelation and calcineurin inhibition, a finding mediated by inhibition of degradation of the NFκB inhibitory protein IκBβ. In contrast, calcium ionophore exposure increased CpG-induced IκBβ degradation and IL1α and IL1β expression. These results demonstrate that through its effect on IκBβ degradation, increased intracellular Ca²⁺ drives a pro-inflammatory TLR9-mediated innate immune response. These results have implications for the study of innate immune signalling downstream of mitochondrial stress and injury.

Mitochondrial pharmacology: featured mechanisms and approaches for therapy translation

LINKED ARTICLES

This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.

Inhibiting nucleolin reduces inflammation induced by mitochondrial DNA in cardiomyocytes exposed to hypoxia and reoxygenation

BACKGROUND AND PURPOSE

Cellular debris causes sterile inflammation after myocardial infarction. Mitochondria constitute about 30 percent of the human heart. Mitochondrial DNA (mtDNA) is a damage-associated-molecular-pattern that induce injurious sterile inflammation. Little is known about mtDNA's inflammatory signalling pathways in cardiomyocytes and how mtDNA is internalized to associate with its putative receptor, toll-like receptor 9 (TLR9).

EXPERIMENTAL APPROACH

We hypothesized that mtDNA can be internalized in cardiomyocytes and induce an inflammatory response. Adult mouse cardiomyocytes were exposed to hypoxia-reoxygenation and extracellular DNA. Microscale thermophoresis was used to demonstrate binding between nucleolin and DNA.

KEY RESULTS

Expression of the pro-inflammatory cytokines IL-1β and TNFα were upregulated by mtDNA, but not by nuclear DNA (nDNA), in cardiomyocytes exposed to hypoxia-reoxygenation. Blocking the RNA/DNA binding protein nucleolin with midkine reduced expression of IL-1β/TNFα and the nucleolin inhibitor AS1411 reduced interleukin-6 release in adult mouse cardiomyocytes. mtDNA bound 10-fold stronger than nDNA to nucleolin. In HEK293-NF-κB reporter cells, mtDNA induced NF-κB activity in normoxia, while CpG-DNA and hypoxia-reoxygenation, synergistically induced TLR9-dependent NF-κB activity. Protein expression of nucleolin was found in the plasma membrane of cardiomyocytes and inhibition of nucleolin with midkine inhibited cellular uptake of CpG-DNA. Inhibition of endocytosis did not reduce CpG-DNA uptake in cardiomyocytes.

CONCLUSION AND IMPLICATIONS

mtDNA, but not nDNA, induce an inflammatory response in mouse cardiomyocytes during hypoxia-reoxygenation. In cardiomyocytes, nucleolin is expressed on the membrane and blocking nucleolin reduce inflammation. Nucleolin might be a therapeutic target to prevent uptake of immunogenic DNA and reduce inflammation.

LINKED ARTICLES

This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.