IL-10 attenuates OxPCs-mediated lipid metabolic responses in ischemia reperfusion injury

Doxorubicin‑induced cardiomyopathy is mitigated by empagliflozin via the modulation of endoplasmic reticulum stress pathways

Doxorubicin (Dox) exhibits a high efficacy in the treatment of numerous types of cancer. However, the beneficial cytotoxic effects of Dox are often accompanied by an increase in the risk of cardiotoxicity. Oxidative stress (OS) plays a key role in Dox‑induced cardiomyopathy (DIC). OS in cardiomyocytes disrupts endoplasmic reticulum (ER) function, leading to the accumulation of misfolded/unfolded proteins known as ER stress. ER stress acts as an adaptive mechanism; however, prolonged ER stress together with OS may lead to the initiation of cardiomyocyte apoptosis. The present study aimed to explore the potential of an anti‑diabetic drug, empagliflozin (EMPA), in mitigating Dox‑induced ER stress and cardiomyocyte apoptosis. In the present study, the effects of 1 h pretreatment of EMPA on Dox‑treated cardiomyocytes isolated from Sprague‑Dawley rats were investigated. After 24 h, EMPA pre‑treatment promoted cell survival in the EMPA + Dox group compared with the Dox group. Results of the present study also demonstrated that EMPA mitigated overall ER stress, as the increased expression of ER stress markers was reduced in the EMPA + Dox group. Additionally, OS, inflammation and expression of ER stress apoptotic proteins were also significantly reduced following EMPA pre‑treatment in the EMPA + Dox group. Thus, EMPA may exert beneficial effects on Dox‑induced ER stress and may exhibit potential changes that can be utilised to further evaluate the role of EMPA in mitigating DIC.

IL-10 protects against OPC ferroptosis by regulating lipid reactive oxygen species levels post stroke

Accumulation of reactive oxygen species (ROS), especially on lipids, induces massive cell death in neurons and oligodendrocyte progenitor cells (OPCs) and causes severe neurologic deficits post stroke. While small compounds, such as deferoxamine, lipostatin-1, and ferrostatin-1, have been shown to be effective in reducing lipid ROS, the mechanisms by which endogenously protective molecules act against lipid ROS accumulation and subsequent cell death are still unclear, especially in OPCs, which are critical for maintaining white matter integrity and improving long-term outcomes after stroke. Here, using mouse primary OPC cultures, we demonstrate that interleukin-10 (IL-10), a cytokine playing roles in reducing neuroinflammation and promoting hematoma clearance, significantly reduced hemorrhage-induced lipid ROS accumulation and subsequent ferroptosis in OPCs. Mechanistically, IL-10 activated the IL-10R/STAT3 signaling pathway and upregulated the DLK1/AMPK/ACC axis. Subsequently, IL-10 reprogrammed lipid metabolism and reduced lipid ROS accumulation. In addition, in an autologous blood injection intracerebral hemorrhagic stroke (ICH) mouse model, deficiency of the endogenous Il-10, specific knocking out Il10r or Dlk1 in OPCs, or administration of ACC inhibitor was associated with increased OPC cell death, demyelination, axonal sprouting, and the cognitive deficits during the chronic phase of ICH and vice versa. These data suggest that IL-10 protects against OPC loss and white matter injury by reducing lipid ROS, supporting further development of potential clinical applications to benefit patients with stroke and related disorders.

Localized cardiac small molecule trajectories and persistent chemical sequelae in experimental Chagas disease

Post-infectious conditions present major health burdens but remain poorly understood. In Chagas disease (CD), caused by Trypanosoma cruzi parasites, antiparasitic agents that successfully clear T. cruzi do not always improve clinical outcomes. In this study, we reveal differential small molecule trajectories between cardiac regions during chronic T. cruzi infection, matching with characteristic CD apical aneurysm sites. Incomplete, region-specific, cardiac small molecule restoration is observed in animals treated with the antiparasitic benznidazole. In contrast, superior restoration of the cardiac small molecule profile is observed for a combination treatment of reduced-dose benznidazole plus an immunotherapy, even with less parasite burden reduction. Overall, these results reveal molecular mechanisms of CD treatment based on simultaneous effects on the pathogen and on host small molecule responses, and expand our understanding of clinical treatment failure in CD. This link between infection and subsequent persistent small molecule perturbation broadens our understanding of infectious disease sequelae.

Myeloid PTP1B deficiency protects against atherosclerosis by improving cholesterol homeostasis through an AMPK-dependent mechanism

OBJECTIVE

Atherosclerosis is a chronic inflammatory process induced by the influx and entrapment of excess lipoproteins into the intima media of arteries. Previously, our lab demonstrated that systemic PTP1B inhibition protects against atherosclerosis in preclinical LDLR-/- models. Similarly, it was shown that myeloid-specific PTP1B ablation decreases plaque formation and ameliorates dyslipidaemia in the ApoE-/- model of atherosclerosis. We hypothesized that the relevant improvements in dyslipidaemia following modification of PTP1B activation may either result from changes in hepatic cholesterol biosynthesis and/or increased uptake and degradation by liver-resident macrophages. We examined this in animal models and patients with coronary artery disease.

METHODS

In this study, we determined the cholesterol-lowering effect of myeloid-PTP1B deletion in mice fed a high-fat high-cholesterol diet and examined effects on total cholesterol levels and lipoprotein profiles. We also determined the effects of PTP1B inhibition to oxLDL-C challenge on foam cell formation and cholesterol efflux in human monocytes/macrophages.

RESULTS

We present evidence that myeloid-PTP1B deficiency significantly increases the affinity of Kupffer cells for ApoB containing lipoproteins, in an IL10-dependent manner. We also demonstrate that PTP1B inhibitor, MSI-1436, treatment decreased foam cell formation in Thp1-derived macrophages and increased macrophage cholesterol efflux to HDL in an AMPK-dependent manner. We present evidence of three novel and distinct mechanisms regulated by PTP1B: an increase in cholesterol efflux from foam cells, decreased uptake of lipoproteins into intra-lesion macrophages in vitro and a decrease of circulating LDL-C and VLDL-C in vivo.

CONCLUSIONS

Overall, these results suggest that myeloid-PTP1B inhibition has atheroprotective effects through improved cholesterol handling in atherosclerotic lesions, as well as increased reverse cholesterol transport. Trial registration Research registry, researchregistry 3235. Registered 07 November 2017, https://www.researchregistry.com/browse-the-registry#home/registrationdetails/5a01d0fce7e1904e93e0aac5/ .

Initial exploration of a novel fusion protein, IL-4/IL-34/IL-10, which promotes cardiac allograft survival mice through alloregulation

Immune mediated graft loss still represents a major risk to transplant recipients. Creative approaches to immunosuppression that exploit the recipient's own alloregulatory mechanisms could reduce the need for pharmacologic immunosuppression and potentially induce immune tolerance. In the process of studying recipient derived myeloid derived suppressor cells (MDSCs), we identified key alloregulatory MDSC mechanisms, mediated by isolatable proteins IL-4, IL-34, and IL-10. We sought to purify these proteins and fuse them for subsequent infusion into transplant recipients as a means of inducing an alloregulatory response. In this introductory investigation, we leveraged molecular engineering technology to create a fusion protein (FP) of three cytokine coding sequences of IL-4, IL-34, and IL-10 and demonstrated their expressions by Western Blot analysis. Following purification, we tested whether FP IL-4/IL-34/IL-10 (FP1) can protect heart transplant allografts. Injection of FP1 significantly prolonged allogeneic cardiac graft survival in a dose-dependent fashion and the increase of graft survival time exceeded survival attributable to IL-34 alone. In vitro, MDSCs cells were expanded by FP1 treatment. However, FP1 did not directly inhibit T cell proliferation in vitro. In conclusion, newly developed FP1 improves the graft survival in cardiac transplantation mouse model. Significant additional work to optimize FP1 or include other novel proteins could supplement current treatment options for transplant patients.

Targeted Lipidomics and Inflammation Response to Six Weeks of Sprint Interval Training in Male Adolescents

Lipids play an important role in coordinating and regulating metabolic and inflammatory processes. Sprint interval training (SIT) is widely used to improve sports performance and health outcomes, but the current understanding of SIT-induced lipid metabolism and the corresponding systemic inflammatory status modification remains controversial and limited, especially in male adolescents. To answer these questions, twelve untrained male adolescents were recruited and underwent 6 weeks of SIT. The pre- and post-training testing included analyses of peak oxygen consumption (VO2peak), biometric data (weight and body composition), serum biochemical parameters (fasting blood glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triacylglycerol, testosterone, and cortisol), inflammatory markers, and targeted lipidomics. After the 6-week SIT, the serum C-reactive protein (CRP), interleukin (IL)-1β, IL-2, IL-4, IL-10, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β significantly decreased (p < 0.05), whereas IL-6 and IL-10/TNF-α significantly increased (p < 0.05). In addition, the targeted lipidomics revealed changes in 296 lipids, of which 33 changed significantly (p < 0.05, fold change > 1.2 or <1/1.2). The correlation analysis revealed that the changes in the inflammatory markers were closely correlated with the changes in some of the lipids, such as LPC, HexCer, and FFA. In conclusion, the 6-week SIT induced significant changes in the inflammatory markers and circulating lipid composition, offering health benefits to the population.

Upregulated miR-18a-5p in Colony Forming Unit-Hill’s in Subclinical Cardiovascular Disease and Metformin Therapy; MERIT Study

Colony forming unit-Hill’s (CFU-Hill’s) colonies are hematopoietic-derived cells that participate in neovasculogenesis and serve as a biomarker for vascular health. In animals, overexpression of miR-18a-5p was shown to be pro-atherogenic. We had shown that well-controlled type 1 diabetes mellitus (T1DM) is characterized by an inflammatory state, endothelial dysfunction, and reduced number of CFU-Hill’s, a model of subclinical cardiovascular disease (CVD). MERIT study explored the role of miR-18a-5p expression in CFU-Hill’s colonies in T1DM, and the cardioprotective effect of metformin in subclinical CVD. In T1DM, miR-18a-5p was significantly upregulated whereas metformin reduced it to HC levels. MiR-18a-5p was inversely correlated with CFU-Hill’s colonies, CD34+, CD34+CD133+ cells, and positively with IL-10, C-reactive protein, vascular endothelial growth factor-D (VEGF-D), and thrombomodulin. The receiver operating characteristic curve demonstrated, miR-18a-5p as a biomarker of T1DM, and upregulated miR-18a-5p defining subclinical CVD at HbA1c of 44.5 mmol/mol (pre-diabetes). Ingenuity pathway analysis documented miR-18a-5p inhibiting mRNA expression of insulin-like growth factor-1, estrogen receptor-1, hypoxia-inducible factor-1α cellular communication network factor-2, and protein inhibitor of activated STAT 3, whilst metformin upregulated these mRNAs via transforming growth factor beta-1 and VEGF. We confirmed the pro-atherogenic effect of miR-18a-5p in subclinical CVD and identified several target genes for future CVD therapies.

The structural basis of effective LOX-1 inhibition

Along with other scavenger receptors, splice variants of LOX-1 play an important role in modulating numerous subcellular mechanisms such as normal cell development, differentiation and growth in response to physiological stimuli. Thus, LOX-1 activity is a key regulator in determining the severity of many genetic, metabolic, cardiovascular, renal, and neurodegenerative diseases and/or cancer. Increased expression of LOX-1 precipitates pathological disorders during the aging process. Therefore, it becomes important to develop novel LOX-1 inhibitors based on its ligand binding polarity and/or affinity and disrupt the uptake of its ligand: oxidized low-density lipoproteins (ox-LDL). In this review, we shed light on the presently studied and developed novel LOX-1 inhibitors that may have potential for treatment of diseases characterized by LOX-1 activation.

Interleukin-10 Mitigates Doxorubicin-Induced Endoplasmic Reticulum Stress as Well as Cardiomyopathy

The use of doxorubicin (Dox) in cancer patients carries the risk of cardiotoxicity via an increase in oxidative stress, mitochondrial dysfunction, and disturbed endoplasmic reticulum (ER) homeostasis in cardiomyocytes. The present study explores which of the ER transmembrane sensors is involved in Dox-induced apoptosis and whether interleukin-10 (IL-10) has any mitigating effect. There was a time-related increase in apoptosis in cardiomyocytes exposed to 5.43 µg/mL Dox for 0 to 48 h. Dox treatment for 24 h significantly upregulated glucose-regulated proteins 78 and 94, protein disulfide isomerase, cleavage of activating transcription factor 6α, and X-box binding protein 1. These Dox-induced changes in ER stress proteins as well as apoptosis were blunted by IL-10 (10 ng/mL). In Dox-exposed cardiomyocytes, IL-10 also promoted expression of protein kinase-like endoplasmic reticulum kinase and inositol-requiring kinase 1α, which helped in maintaining ER homeostasis. Additionally, under Dox-treatment, IL-10 downregulated caspase-12 activation as well as phosphorylation of c-JUN NH2-terminal kinase, thereby promoting cardiomyocyte survival. IL-10 was able to reduce the overexpression of mitochondrial apoptotic proteins caspase-3 as well as Bax, which were upregulated upon Dox treatment. Thus, a reduction in Dox-induced ER stress as well as apoptosis through IL-10 may provide a significant benefit in improving cardiac function.

Increase in Plasma Oxidized Phosphatidylcholines (OxPCs) in Patients Presenting With ST-Elevation Myocardial Infarction (STEMI)

Objective: ST-segment Elevation Myocardial Infarction (STEMI) occurs as a result of acute occlusion of the coronary artery. Despite successful reperfusion using percutaneous coronary intervention (PCI), a large percentage of myocardial cells die after reperfusion which is recognized as ischemia/reperfusion injury (I/R). Oxidized phosphatidylcholines (OxPCs) are a group of oxidized lipids generated through non-enzymatic oxidation and have pro-inflammatory properties. This study aimed to examine the roles of OxPCs in a clinical setting of myocardial I/R.

Methods: Blood samples were collected from STEMI patients at presentation prior to primary PCI (PPCI) (Isch) and at 4 time-points post-PPCI, including 2 h (R-2 h), 24 h (R-24 h), 48 h (R-48 h), and 30 days (R-30 d) post-PPCI. As controls, blood samples were collected from patients with non-obstructive coronary artery disease after diagnostic coronary angiography. Aspiration thrombectomy was also performed in selected STEMI patients. High-performance lipid chromatography-electrospray mass spectrometry (LC-MS/MS) was used for OxPCs analysis.

Results: Twenty-two distinct OxPC species were identified and quantified in plasma samples in patients presenting with STEMI. These compounds were categorized as fragmented and non-fragmented species. Total levels of OxPCs did not significantly differ between Isch and control groups. However, total levels of fragmented OxPCs increased significantly in the ischemic period compared with controls (Isch: 4.79 ± 0.94, Control: 1.69 ± 0.19 ng/μl of plasma, P < 0.05). Concentrations of non-fragmented OxPCs had significant reductions during ischemia compared to the control group (Isch: 4.84 ± 0.30, Control: 6.6 ± 0.51 ng/μl, P < 0.05). Levels of total OxPCs in patients with STEMI were not significantly different during reperfusion periods. However, fragmented OxPCs levels were elevated at 48 h post-reperfusion and decreased at 30 days following MI, when compared to R-2 h and R-24 h time points (Isch: 4.79 ± 0.94, R-2 h: 5.33 ± 1.17, R-24 h: 5.20 ± 1.1, R-48 h: 4.18 ± 1.07, R-30 d: 1.87 ± 0.31 ng/μl, P < 0.05). Plasma levels of two fragmented OxPCs, namely, POVPC and PONPC were significantly correlated with peak creatine kinase (CK) levels (P < 0.05). As with plasma levels, the dominant OxPC species in coronary aspirated thrombus were fragmented OxPCs, which constituted 77% of total OxPC concentrations.

Conclusion: Biologically active fragmented OxPC were elevated in patients presenting with STEMI when compared to controls. PONPC concentrations were subsequently increased after PPCI resulting in reperfusion. Moreover, levels of POVPC and PONPC were also associated with peak CK levels. Since these molecules are potent stimulators for cardiomyocyte cell death, therapeutics attenuating their activities can result in a novel therapeutic pathway for myocardial salvage for patients undergoing reperfusion therapy.

Ischemia-Reperfusion Injury in Peripheral Artery Disease and Traditional Chinese Medicine Treatment

Peripheral artery disease (PAD) is a serious public health issue, characterized by circulation disorder of the lower extreme that reduces the physical activity of the lower extremity muscle. The artery narrowed by atherosclerotic lesions initiates limb ischemia. In the progression of treatment, reperfusion injury is still inevitable. Ischemia-reperfusion injury induced by PAD is responsible for hypoxia and nutrient deficiency. PAD triggers hindlimb ischemia and reperfusion (I/R) cycles through various mechanisms, mainly including mitochondrial dysfunction and inflammation. Alternatively, mitochondrial dysfunction plays a central role. The I/R injury may cause cells' injury and even death. However, the mechanism of I/R injury and the way of cell damage or death are still unclear. We review the pathophysiology of I/R injury, which is majorly about mitochondrial dysfunction. Then, we focus on the cell damage and death during I/R injury. Further comprehension of the progress of I/R will help identify biomarkers for diagnosis and therapeutic targets to PAD. In addition, traditional Chinese medicine has played an important role in the treatment of I/R injury, and we will make a brief introduction.

Endoplasmic Reticulum Stress Promotes iNOS/NO and Influences Inflammation in the Development of Doxorubicin-Induced Cardiomyopathy

Doxorubicin (Dox) is known to cause heart failure in some cancer patients. Despite extensive studies over the past half century, the subcellular basis of Dox-induced cardiomyopathy (DIC) is still elusive. Earlier, we suggested that Dox causes a delayed activation of unfolded protein response (UPR) which may promote mitochondrial Bax activity leading to cardiomyocyte death. As a follow up, using NO donor, S-Nitroso-N-acetyl-d,l-penicillamine (SNAP), and/or NOS inhibitor, N(ω)-nitro-L-arginine methyl ester (L-NAME), we now show that endoplasmic reticulum (ER) stress promotes inflammation through iNOS/NO-induced TLR2 activation. In vivo Dox treatment increased mitochondrial iNOS to promote ER stress as there was an increase in Bip (Grp78) response, proapoptotic CHOP (DDIT3) and ER-mediated Caspase 12 activation. Increased iNOS activity is associated with an increase in TLR2 and TNF-α receptor associated factor 2 (TRAF2). These two together with NF-κB p105/50 expression and a synergistic support through ER stress, promote inflammatory response in the myocardium leading to cell death and ultimately fostering DIC conditions. In the presence of NOS inhibitor, such detrimental effects of Dox were inhibited, suggesting iNOS/NO as key mediators of Dox-induced inflammatory as well as apoptotic responses.

Lipid metabolism in sickness and in health: Emerging regulators of lipotoxicity

Lipids play crucial roles in signal transduction, contribute to the structural integrity of cellular membranes, and regulate energy metabolism. Questions remain as to which lipid species maintain metabolic homeostasis and which disrupt essential cellular functions, leading to metabolic disorders. Here, we discuss recent advances in understanding lipid metabolism with a focus on catabolism, synthesis, and signaling. Technical advances, including functional genomics, metabolomics, lipidomics, lipid-protein interaction maps, and advances in mass spectrometry, have uncovered new ways to prioritize molecular mechanisms mediating lipid function. By reviewing what is known about the distinct effects of specific lipid species in physiological pathways, we provide a framework for understanding newly identified targets regulating lipid homeostasis with implications for ameliorating metabolic diseases.

Elucidating the interaction between maternal physical activity and circulating myokines throughout gestation: A scoping review

Physical activity (PA) during pregnancy provides both maternal and fetal health benefits. It has been theorized that myokines, peptides secreted by contracting skeletal muscle, may play an important mechanistic role in facilitating the health benefits obtained from prenatal exercise. The objective of this review was to synthesize the current literature on the relationship between maternal PA and myokine response. A search strategy was developed using the terms pregnancy, PA, IL-6, IL-10, IL-13, and TNF-α. A systematic search was completed in July 2020, in Medline, SPORTDiscus, EMBASE, CENTRAL, and in November 2020 for unpublished dissertations (grey literature; Proquest). Both human- and animal-based studies of any design were included, while commentaries and editorial articles were excluded. Data were extracted by two independent reviewers and summarized narratively. Data were thematically summarized based on the myokine and whether findings were from human or animal studies. Ten studies were included in this review. Findings from studies that examined IL-6, IL-10, and TNF-α suggest a trimester-specific interaction between PA and myokine levels; no studies evaluated IL-13. Future research should investigate the PA-myokine relationship throughout all stages of gestation.

Study of ER stress and apoptotic proteins in the heart and tumor exposed to doxorubicin

Although a high cumulative dose of Doxorubicin (Dox) is known to cause cardiotoxicity, there is still a lack of understanding of the subcellular basis of this drug-induced cardiomyopathy. Differential effects of Dox on mitochondria and endoplasmic reticulum (ER) were examined in cardiomyocytes, tumor cells, implanted tumors and hearts of normal as well as tumor-bearing animals. Dox increased mitochondrial (Mito) Bax activation at 3 h in the cardiomyocyte without change in the DNA damage inducible transcriptor-3 (DDIT3) expression in the ER. Increased DDIT3 in these Dox-treated cardiomyocytes at 24 h suggested that increased MitoBax may have promoted ER stress related changes in DDIT3. Dissociation of immunoglobulin-binding protein (Bip) from activating transcription factor 6 (ATF6)-Bip complex in the ER was observed as an adaptive response to Dox. In contrast, breast cancer MCF7 cells showed an ER stress response to Dox with increased DDIT3 as early as 3 h which may have triggered a positive feedback activation of ATF6 at 12 and 24 h and promoted Calnexin. At these later time points, increased Bax activation in cancer cells suggested that MitoBax may be controlled by DDIT3 or by Calnexin. DDIT3 response in tumors was evoked by Dox, however this response was inversely correlated with increased Bip and Bax expression in hearts from tumor bearing animals. It is suggested that in Dox-induced cardiotoxicity both mitochondrial and ER stresses play an integral role through a mutual interaction where an inhibition of DDIT3 or Calnexin may also be crucial to achieve Dox resistance in cardiomyocytes.

Lipidomics Provides New Insight into Pathogenesis and Therapeutic Targets of the Ischemia-Reperfusion Injury

Lipids play an essential role in both tissue protection and damage. Tissue ischemia creates anaerobic conditions in which enzyme inactivation occurs, and reperfusion can initiate oxidative stress that leads to harmful changes in membrane lipids, the formation of aldehydes, and chain damage until cell death. The critical event in such a series of harmful events in the cell is the unwanted accumulation of fatty acids that leads to lipotoxicity. Lipid analysis provides additional insight into the pathogenesis of ischemia/reperfusion (I/R) disorders and reveals new targets for drug action. The profile of changes in the composition of fatty acids in the cell, as well as the time course of these changes, indicate both the mechanism of damage and new therapeutic possibilities. A therapeutic approach to reperfusion lipotoxicity involves attenuation of fatty acids overload, i.e., their transport to adipose tissue and/or inhibition of the adverse effects of fatty acids on cell damage and death. The latter option involves using PPAR agonists and drugs that modulate the transport of fatty acids via carnitine into the interior of the mitochondria or the redirection of long-chain fatty acids to peroxisomes.