IκB Kinase Inhibitor Attenuates Sepsis-Induced Cardiac Dysfunction in CKD

Astragalus Complanatus Ethanol Attenuates Septic Shock by Exerting Anti-Inflammatory Effects on Macrophages

Sepsis is a systemic inflammatory syndrome that results in multiple-organ failure caused by a dysregulated host immune response to microbial infection. Astragali complanati semen extract (ACSE) exhibits pharmacological activities, including antioxidant, anticancer, antiaging, and anti-diabetes effects. It is widely used in traditional medicine to treat liver and kidney diseases; however, the protective effect of ACSE on sepsis and its mechanisms are unknown. In the present study, we investigated the anti-inflammatory effects and potential mechanisms of the action of ACSE on sepsis. We show that ACSE improved survival rates in mouse models of acute sepsis induced by CLP (cecal ligation and puncture) and LPS stimulation. ACSE administration decreased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in sepsis-induced mice. Furthermore, ACSE reduced the levels of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in the serum of septic mice. ACSE treatment inhibited the expression of these proinflammatory genes in LPS-stimulated J774 macrophages. Moreover, ACSE inhibited the phosphorylation of the IκB kinase (IKK) and the nuclear translocation of p65 NF-κB by LPS stimulation in macrophages. These results reveal the mechanism underlying the protective effect of ACSE against sepsis by inhibiting NF-κB activation and suggest that ACSE could be a potential therapeutic candidate to treat acute inflammatory diseases.

Age-related promoter-switch regulates Runx1 expression in adult rat hearts

BACKGROUND

Runt-related transcription factor-1 (RUNX1), a key member of the core-binding factor family of transcription factors, has emerged as a novel therapeutic target for cardiovascular disease. There is an urgent need to fully understand the expression pattern of Runx1 in the heart and the mechanisms by which it is controlled under normal conditions and in response to disease. The expression of Runx1 is regulated at the transcriptional level by two promoters designated P1 and P2. Alternative usage of these two promoters creates differential mRNA transcripts diversified in distribution and translational potential. While the significance of P1/P2 promoter-switch in the transcriptional control of Runx1 has been highlighted in the embryogenic process, very little is known about the level of P1- and P2-specific transcripts in adult hearts, and the underlying mechanisms controlling the promoter-switch.

METHODS

To amplify P1/P2 specific sequences in the heart, we used two different sense primers complementary to either P1 or P2 5'-regions to monitor the expression of P1/P2 transcripts. DNA methylation levels were assessed at the Runx1 promoter regions. Rats were grouped by age.

RESULTS

The expression levels of both P1- and P2-derived Runx1 transcripts were decreased in older rats when compared with that in young adults, paralleled with an age-dependent decline in Runx1 protein level. Furthermore, older rats demonstrated a higher degree of DNA methylation at Runx1 promoter regions. Alternative promoter usage was observed in hearts with increased age, as reflected by altered P1:P2 mRNA ratio.

CONCLUSION

Our data demonstrate that the expression of Runx1 in the heart is age-dependent and underscore the importance of gene methylation in the promoter-mediated transcriptional control of Runx1, thereby providing new insights to the role of epigenetic regulation in the heart.

Baricitinib protects mice from sepsis-induced cardiac dysfunction and multiple-organ failure

Sepsis is one of the major complications of surgery resulting in high morbidity and mortality, but there are no specific therapies for sepsis-induced organ dysfunction. Data obtained under Gene Expression Omnibus accession GSE131761 were re-analyzed and showed an increased gene expression of Janus Kinase 2 (JAK2) and Signal Transducer and Activator of Transcription 3 (STAT3) in the whole blood of post-operative septic patients. Based on these results, we hypothesized that JAK/STAT activation may contribute to the pathophysiology of septic shock and, hence, investigated the effects of baricitinib (JAK1/JAK2 inhibitor) on sepsis-induced cardiac dysfunction and multiple-organ failure (MOF). In a mouse model of post-trauma sepsis induced by midline laparotomy and cecal ligation and puncture (CLP), 10-week-old male (n=32) and female (n=32) C57BL/6 mice received baricitinib (1mg/kg; i.p.) or vehicle at 1h or 3h post-surgery. Cardiac function was assessed at 24h post-CLP by echocardiography in vivo, and the degree of MOF was analyzed by determination of biomarkers in the serum. The potential mechanism underlying both the cardiac dysfunction and the effect of baricitinib was analyzed by western blot analysis in the heart. Trauma and subsequent sepsis significantly depressed the cardiac function and induced multiple-organ failure, associated with an increase in the activation of JAK2/STAT3, NLRP3 inflammasome and NF- κβ pathways in the heart of both male and female animals. These pathways were inhibited by the administration of baricitinib post the onset of sepsis. Moreover, treatment with baricitinib at 1h or 3h post-CLP protected mice from sepsis-induced cardiac injury and multiple-organ failure. Thus, baricitinib may be repurposed for trauma-associated sepsis.

Exogenous fetuin-A protects against sepsis-induced myocardial injury by inhibiting oxidative stress and inflammation in mice

Sepsis-induced myocardial injury is a consequence of septicemia and is one of the major causes of death in intensive care units. A serum glycoprotein called fetuin-A is secreted largely by the liver, tongue, placenta, and adipose tissue. Fetuin-A has a variety of biological and pharmacological properties. The anti-inflammatory and antioxidant glycoprotein fetuin-A has shown its efficacy in a number of inflammatory disorders including sepsis. However, its protective role against sepsis-induced myocardial injury remains elusive. The purpose of this work is to explore the role of fetuin-A in mouse models of myocardial injury brought on by cecal ligation and puncture (CLP). CLP significantly induced the myocardial injury assessed in terms of elevated myocardial markers (serum CK-MB, cTnI levels), inflammatory markers (IL-6, TNF-α) in the serum, and oxidative stress markers (increased MDA levels and decreased reduced glutathione) in heart tissue homogenate following 24 h of ligation and puncture. Further, hematoxylin and eosin (H&E) staining showed considerable histological alterations in the myocardial tissue of sepsis-developed mice. Interestingly, fetuin-A pretreatment (50 and 100 mg/kg) for 4 days before the CLP procedure significantly improved the myocardial injury and was evaluated in perspective of a reduction in the CK-MB, cTnI levels, IL-6, and TNF-α in sepsis-developed animals. Fetuin-A pretreatment significantly attenuated the oxidative stress and improved the myocardial morphology in a dose-dependent manner. The present study provides preliminary evidence that fetuin-A exerts protection against sepsis-induced cardiac dysfunction in vivo via suppression of inflammation and oxidative damage.

Formyl Peptide Receptor Type 2 Deficiency in Myeloid Cells Amplifies Sepsis-Induced Cardiac Dysfunction

Using a global formyl peptide receptor (Fpr) 2 knockout mouse colony, we have reported the modulatory properties of this pro-resolving receptor in polymicrobial sepsis. Herein, we have used a humanized FPR2 (hFPR2) mouse colony, bearing an intact or a selective receptor deficiency in myeloid cells to dwell on the cellular mechanisms. hFPR2 mice and myeloid cell-specific hFPR2 KO (KO) mice were subjected to cecal ligation and puncture (CLP)-induced polymicrobial sepsis. Compared with hFPR2 mice, CLP caused exacerbated cardiac dysfunction (assessed by echocardiography), worsened clinical outcome, and impaired bacterial clearance in KO mice. This pathological scenario was paralleled by increased recruitment of pro-inflammatory monocytes and reduced M2-like macrophages within the KO hearts. In peritoneal exudates of KO mice, we quantified increased neutrophil and MHC II+ macrophage numbers but decreased monocyte/macrophage and MHC II- macrophage recruitment. hFPR2 upregulation was absent in myeloid cells, and local production of lipoxin A4 was reduced in septic KO mice. Administration of the FPR2 agonist annexin A1 (AnxA1) improved cardiac function in hFPR2 septic mice but had limited beneficial effects in KO mice, in which the FPR2 ligand failed to polarize macrophages toward an MHC II- phenotype. In conclusion, FPR2 deficiency in myeloid cells exacerbates cardiac dysfunction and worsens clinical outcome in polymicrobial sepsis. The improvement of cardiac function and the host immune response by AnxA1 is more effective in hFPR2-competent septic mice.

Lipid Nanoparticles for Nucleic Acid Delivery to Endothelial Cells

Endothelial cells play critical roles in circulatory homeostasis and are also the gateway to the major organs of the body. Dysfunction, injury, and gene expression profiles of these cells can cause, or are caused by, prevalent chronic diseases such as diabetes, cardiovascular disease, and cancer. Modulation of gene expression within endothelial cells could therefore be therapeutically strategic in treating longstanding disease challenges. Lipid nanoparticles (LNP) have emerged as potent, scalable, and tunable carrier systems for delivering nucleic acids, making them attractive vehicles for gene delivery to endothelial cells. Here, we discuss the functions of endothelial cells and highlight some receptors that are upregulated during health and disease. Examples and applications of DNA, mRNA, circRNA, saRNA, siRNA, shRNA, miRNA, and ASO delivery to endothelial cells and their targets are reviewed, as well as LNP composition and morphology, formulation strategies, target proteins, and biomechanical factors that modulate endothelial cell targeting. Finally, we discuss FDA-approved LNPs as well as LNPs that have been tested in clinical trials and their challenges, and provide some perspectives as to how to surmount those challenges.

Bruton's TK regulates myeloid cell recruitment during acute inflammation

BACKGROUND AND PURPOSE

Bruton's TK (BTK) is a non-receptor kinase best known for its role in B lymphocyte development that is critical for proliferation and survival of leukaemic cells in B-cell malignancies. However, BTK is expressed in myeloid cells, particularly neutrophils, monocytes and macrophages where its inhibition has been reported to cause anti-inflammatory properties.

EXPERIMENTAL APPROACH

We explored the role of BTK on migration of myeloid cells (neutrophils, monocytes and macrophages), in vitro using chemotaxis assays and in vivo using zymosan-induced peritonitis as model systems.

KEY RESULTS

Using the zymosan-induced peritonitis model of sterile inflammation, we demonstrated that acute inhibition of BTK prior to zymosan challenge reduced phosphorylation of BTK in circulating neutrophils and monocytes. Moreover, pharmacological inhibition of BTK with ibrutinib specifically inhibited neutrophil and Ly6Chi monocytes, but not Ly6Clo monocyte recruitment to the peritoneum. X-linked immunodeficient (XID) mice, which have a point mutation in the Btk gene, had reduced neutrophil and monocyte recruitment to the peritoneum following zymosan challenge. Pharmacological or genetic inhibition of BTK signalling substantially reduced human monocyte and murine macrophage chemotaxis, to a range of clinically relevant chemoattractants (C5a and CCL2). We also demonstrated that inhibition of BTK in tissue resident macrophages significantly decreases chemokine secretion by reducing NF-κB activity and Akt signalling.

CONCLUSION AND IMPLICATIONS

Our work has identified a new role of BTK in regulating myeloid cell recruitment via two mechanisms, reducing monocyte/macrophages' ability to undergo chemotaxis and reducing chemokine secretion, via reduced NF-κB and Akt activity in tissue resident macrophages.

Regulation of the Tec family of non-receptor tyrosine kinases in cardiovascular disease

Tyrosine phosphorylation by protein tyrosine kinases (PTKs) is a type of post-translational modification. Tec kinases, which are a subfamily of non-receptor PTKs, were originally discovered in the hematopoietic system and include five members: Tec, Btk, Itk/Emt/Tsk, Etk/Bmx, and Txk/Rlk. With the progression of modern research, certain members of the Tec family of kinases have been found to be expressed outside the hematopoietic system and are involved in the development and progression of a variety of diseases. The role of Tec family kinases in cardiovascular disease is receiving increasing attention. Tec kinases are involved in the occurrence and progression of ischemic heart disease, atherosclerosis, cardiac dysfunction associated with sepsis, atrial fibrillation, myocardial hypertrophy, coronary atherosclerotic heart disease, and myocardial infarction and post-myocardial. However, no reviews have comprehensively clarified the role of Tec kinases in the cardiovascular system. Therefore, this review summarizes research on the role of Tec kinases in cardiovascular disease, providing new insights into the prevention and treatment of cardiovascular disease.

Increased m6A-RNA methylation and FTO suppression is associated with myocardial inflammation and dysfunction during endotoxemia in mice

Endotoxemia triggers life-threatening immune and cardiovascular response that leads to tissue damage, multi-organ failure, and death. The understanding of underlying molecular mechanisms is still evolving. N6-methyladenosine (m6A)-RNA modification plays key regulatory role in numerous biological processes. However, it remains unclear whether endotoxemia alters RNA methylation in the myocardium. In the current study, we investigated the effect of lipopolysaccharide (LPS)-induced endotoxemia on m6A-RNA methylation and its implications on myocardial inflammation and left ventricular (LV) function. Following LPS administration, mice showed increases in m6A-RNA methylation in the myocardium with a corresponding decrease in the expression of fat mass and obesity-associated protein (FTO, an m6A eraser/demethylase). The changes were associated with a significant increase in expression of myocardial inflammatory cytokine genes, such as IL-6, TNF-α, IL-1β, and reduced LV function. Moreover, rat cardiomyoblasts (H9c2) exposed to LPS showed similar changes (with increase in m6A-RNA methylation and inflammatory cytokine genes, whereas downregulation of FTO). Furthermore, methylated RNA immunoprecipitation assay showed hypermethylation and increase in the expression of IL-6 and TNF-α genes in LPS-treated H9c2 cells as compared to untreated cells. Interestingly, FTO knockdown in cardiomyocytes mimicked the above effects. Taken together, these data suggest that endotoxemia-induced m6A methylation might play a critical role in expression of cardiac proinflammatory cytokines, and modulation of m6A methylation might limit myocardial inflammation and dysfunction during endotoxemia.

A systematic review and meta-analysis of murine models of uremic cardiomyopathy

Chronic kidney disease (CKD) triggers the risk of developing uremic cardiomyopathy as characterized by cardiac hypertrophy, fibrosis and functional impairment. Traditionally, animal studies are used to reveal the underlying pathological mechanism, although variable CKD models, mouse strains and readouts may reveal diverse results. Here, we systematically reviewed 88 studies and performed meta-analyses of 52 to support finding suitable animal models for future experimental studies on pathological kidney-heart crosstalk during uremic cardiomyopathy. We compared different mouse strains and the direct effect of CKD on cardiac hypertrophy, fibrosis and cardiac function in "single hit" strategies as well as cardiac effects of kidney injury combined with additional cardiovascular risk factors in "multifactorial hit" strategies. In C57BL/6 mice, CKD was associated with a mild increase in cardiac hypertrophy and fibrosis and marginal systolic dysfunction. Studies revealed high variability in results, especially regarding hypertrophy and systolic function. Cardiac hypertrophy in CKD was more consistently observed in 129/Sv mice, which express two instead of one renin gene and more consistently develop increased blood pressure upon CKD induction. Overall, "multifactorial hit" models more consistently induced cardiac hypertrophy and fibrosis compared to "single hit" kidney injury models. Thus, genetic factors and additional cardiovascular risk factors can "prime" for susceptibility to organ damage, with increased blood pressure, cardiac hypertrophy and early cardiac fibrosis more consistently observed in 129/Sv compared to C57BL/6 strains.

Fibroblast-specific IKKβ deficiency ameliorates angiotensin II-induced adverse cardiac remodeling in mice

Cardiac inflammation and fibrosis contribute significantly to hypertension-related adverse cardiac remodeling. IκB kinase β (IKK-β), a central coordinator of inflammation through activation of NF-κB, has been demonstrated as a key molecular link between inflammation and cardiovascular disease. However, the cell-specific contribution of IKK-β signaling toward adverse cardiac remodeling remains elusive. Cardiac fibroblasts are one of the most populous nonmyocyte cell types in the heart that play a key role in mediating cardiac fibrosis and remodeling. To investigate the function of fibroblast IKK-β, we generated inducible fibroblast-specific IKK-β–deficient mice. Here, we report an important role of IKK-β in the regulation of fibroblast functions and cardiac remodeling. Fibroblast-specific IKK-β–deficient male mice were protected from angiotensin II–induced cardiac hypertrophy, fibrosis, and macrophage infiltration. Ablation of fibroblast IKK-β inhibited angiotensin II–stimulated fibroblast proinflammatory and profibrogenic responses, leading to ameliorated cardiac remodeling and improved cardiac function in IKK-β–deficient mice. Findings from this study establish fibroblast IKK-β as a key factor regulating cardiac fibrosis and function in hypertension-related cardiac remodeling.

Structure of the Mycobacterium tuberculosis cPknF and conformational changes induced in forkhead-associated regulatory domains

Mycobacterium tuberculosis (Mtb) has 11 Serine-Threonine Protein Kinases (STPK) that control numerous physiological processes, including cell growth, cell division, metabolic flow, and transcription. PknF is one of the 11 Mtb STPKs that has, among other substrates, two FHA domains (FHA-1 and FHA-2) of the ATP-Binding Cassette (ABC) transporter Rv1747. Phosphorylation in T152 and T210 located in a non-structured linker that connects Rv1747 FHA domains is considerate to be the regulatory mechanism of the transporter. In this work, we resolved the three-dimensional structure of the PknF catalytic domain (cPknF) in complex with the human kinase inhibitor IKK16. cPknF is conserved when compared to other STPKs but shows specific residues in the binding site where the inhibitor is positioned. In addition, using Small Angle X-Ray Scattering analysis we monitored the behavior of the wild type and three FHA-phosphomimetic mutants in solution, and measured the cPknF affinity for these domains. The kinase showed higher affinity for the non-phosphorylated wild type domain and preference for phosphorylation of T152 inducing the rapprochement of the domains and significant structural changes. The results shed some light on the process of regulating the transporter's activity by phosphorylation and arises important questions about evolution and importance of this mechanism for the bacillus.

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Rv1747 is an ABC transporter which activity is regulated by PknF.

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cPknF is a typical Serine/Threonine Protein Kinase that can be explored as drug target.

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The higher affinity of cPknF for FHA-2 is important for further conformational changes.

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Rv1747 activation model reveals a concatenated activity essential for the system.

The role of PP5 and PP2C in cardiac health and disease

Protein phosphatases are important, for example, as functional antagonists of β-adrenergic stimulation of the mammalian heart. While β-adrenergic stimulations increase the phosphorylation state of regulatory proteins and therefore force of contraction in the heart, these phosphorylations are reversed and thus force is reduced by the activity of protein phosphatases. In this context the role of PP5 and PP2C is starting to unravel. They do not belong to the same family of phosphatases with regard to sequence homology, many similarities with regard to location, activation by lipids and putative substrates have been worked out over the years. We also suggest which pathways for regulation of PP5 and/or PP2C described in other tissues and not yet in the heart might be useful to look for in cardiac tissue. Both phosphatases might play a role in signal transduction of sarcolemmal receptors in the heart. Expression of PP5 and PP2C can be increased by extracellular stimuli in the heart. Because PP5 is overexpressed in failing animal and human hearts, and because overexpression of PP5 or PP2C leads to cardiac hypertrophy and KO of PP5 leads to cardiac hypotrophy, one might argue for a role of PP5 and PP2C in heart failure. Because PP5 and PP2C can reduce, at least in vitro, the phosphorylation state of proteins thought to be relevant for cardiac arrhythmias, a role of these phosphatases for cardiac arrhythmias is also probable. Thus, PP5 and PP2C might be druggable targets to treat important cardiac diseases like heart failure, cardiac hypertrophy and cardiac arrhythmias.

X-Linked Immunodeficient Mice With No Functional Bruton's Tyrosine Kinase Are Protected From Sepsis-Induced Multiple Organ Failure

We previously reported the Bruton's tyrosine kinase (BTK) inhibitors ibrutinib and acalabrutinib improve outcomes in a mouse model of polymicrobial sepsis. Now we show that genetic deficiency of the BTK gene alone in Xid mice confers protection against cardiac, renal, and liver injury in polymicrobial sepsis and reduces hyperimmune stimulation (“cytokine storm”) induced by an overwhelming bacterial infection. Protection is due in part to enhanced bacterial phagocytosis in vivo, changes in lipid metabolism and decreased activation of NF-κB and the NLRP3 inflammasome. The inactivation of BTK leads to reduced innate immune cell recruitment and a phenotypic switch from M1 to M2 macrophages, aiding in the resolution of sepsis. We have also found that BTK expression in humans is increased in the blood of septic non-survivors, while lower expression is associated with survival from sepsis. Importantly no further reduction in organ damage, cytokine production, or changes in plasma metabolites is seen in Xid mice treated with the BTK inhibitor ibrutinib, demonstrating that the protective effects of BTK inhibitors in polymicrobial sepsis are mediated solely by inhibition of BTK and not by off-target effects of this class of drugs.

Enhanced Klotho availability protects against cardiac dysfunction induced by uraemic cardiomyopathy by regulating Ca2+ handling

BACKGROUND AND PURPOSE

Klotho is a membrane-bound or soluble protein, originally identified as an age-suppressing factor and regulator of mineral metabolism. Klotho deficiency is associated with the development of renal disease, but its role in cardiac function in the context of uraemic cardiomyopathy is unknown.

EXPERIMENTAL APPROACH

We explored the effects of Klotho on cardiac Ca2+ cycling. We analysed Ca2+ handling in adult cardiomyocytes from Klotho-deficient (kl/kl) mice and from a murine model of 5/6 nephrectomy (Nfx). We also studied the effect of exogenous Klotho supplementation, by chronic recombinant Klotho treatment, or endogenous Klotho overexpression, using transgenic mice overexpressing Klotho (Tg-Kl), on uraemic cardiomyopathy. Hearts from Nfx mice were used to study Ca2+ sensitivity of ryanodine receptors and their phosphorylation state.

KEY RESULTS

Cardiomyocytes from kl/kl mice showed decreased amplitude of intracellular Ca2+ transients and cellular shortening together with an increase in pro-arrhythmic Ca2+ events compared with cells from wild-type mice. Cardiomyocytes from Nfx mice exhibited the same impairment in Ca2+ cycling as kl/kl mice. Changes in Nfx cardiomyocytes were explained by higher sensitivity of ryanodine receptors to Ca2+ and their increased phosphorylation at the calmodulin kinase type II and protein kinase A sites. Ca2+ mishandling in Nfx-treated mice was fully prevented by chronic recombinant Klotho administration or transgenic Klotho overexpression.

CONCLUSIONS AND IMPLICATIONS

Klotho emerges as an attractive therapeutic tool to improve cardiac Ca2+ mishandling observed in uraemic cardiomyopathy. Strategies that improve Klotho availability are good candidates to protect the heart from functional cardiac alterations in renal disease.

RvE1 Attenuates Polymicrobial Sepsis-Induced Cardiac Dysfunction and Enhances Bacterial Clearance

The development of cardiac dysfunction caused by microbial infection predicts high mortality in sepsis patients. Specialized pro-resolving mediators (SPMs) mediate resolution of inflammation in many inflammatory diseases, and are differentially expressed in plasma of sepsis patients. Here, we investigated whether the levels of SPMs are altered in the murine septic heart following polymicrobial sepsis-induced cardiac dysfunction. Ten weeks-old male C57BL/6 mice were subjected to polymicrobial sepsis induced by cecal ligation and puncture (CLP), which is a clinically relevant sepsis model receiving analgesics, antibiotics, and fluid resuscitation. CLP caused a significant systolic dysfunction assessed by echocardiography. The hearts were subjected to LC-MS/MS based lipid mediator profiling. Many SPMs were significantly reduced in septic hearts, among which RvE1 had a ~93-fold reduction. Treatment of CLP mice with synthetic RvE1 (1 μg/mouse i.v.) at 1 h after CLP increased peritoneal macrophages number, particularly MHC II^- macrophages. RvE1 reduced pro-inflammatory gene expression (interleukin-1β, interleukin-6, and CCL2) in lipopolysaccharide-stimulated bone marrow-derived macrophages (BMDMs) in vitro. RvE1 attenuated cardiac dysfunction in septic mice and increased cardiac phosphorylated Akt; decreased cardiac phosphorylated IκB kinase α/β, nuclear translocation of the NF-κB subunit p65, extracellular signal-regulated kinase 1/2, and c-Jun amino-terminal kinases 1/2. Most notably, RvE1 treatment reduced peritoneal bacterial load and promoted phagocytosis activity of BMDMs. In conclusion, cardiac SPMs, particularly RvE1, are substantially reduced in mice with polymicrobial sepsis. Delayed therapeutic administration of RvE1 to mice with polymicrobial sepsis attenuates the cardiac dysfunction through modulating immuno-inflammatory responses. In addition to the above effects, the ability to enhance bacterial clearance makes RvE1 an ideal therapeutic to reduce the sequalae of polymicrobial sepsis.

Uncovering the Molecular Mechanism of the Qiang-Xin 1 Formula on Sepsis-Induced Cardiac Dysfunction Based on Systems Pharmacology

Cardiac dysfunction is a critical manifestation of sepsis-induced multiorgan failure and results in the high mortality of sepsis. Our previous study demonstrated that a traditional Chinese medicine formula, Qiang-Xin 1 (QX1), ameliorates cardiac tissue damage in septic mice; however, the underlying pharmacology mechanism remains to be elucidated. The present study was aimed at clarifying the protective mechanism of the QX1 formula on sepsis-induced cardiac dysfunction. The moderate sepsis model of mice was established by cecal ligation and puncture surgery. Treatment with the QX1 formula improved the 7-day survival outcome, attenuated cardiac dysfunction, and ameliorated the disruption of myocardial structure in septic mice. Subsequent systems pharmacology analysis found that 63 bioactive compounds and the related 79 candidate target proteins were screened from the QX1 formula. The network analysis showed that the QX1 active components quercetin, formononetin, kaempferol, taxifolin, cryptotanshinone, and tanshinone IIA had a good binding activity with screened targets. The integrating pathway analysis indicated the calcium, PI3K/AKT, MAPK, and Toll-like receptor signaling pathways may be involved in the protective effect of the QX1 formula on sepsis-induced cardiac dysfunction. Further, experimental validation showed that the QX1 formula inhibited the activity of calcium/calmodulin-dependent protein kinase II (CaMKII), MAPK (P38, ERK1/2, and JNK), and TLR4/NF-κB signaling pathways but promoted the activation of the PI3K/AKT pathway. A cytokine array found that the QX1 formula attenuated sepsis-induced upregulated levels of serum IFN-γ, IL-1β, IL-3, IL-6, IL-17, IL-4, IL-10, and TNF-α. Our data suggested that QX1 may represent a novel therapeutic strategy for sepsis by suppressing the activity of calcium, MAPK, and TLR4/NF-κB pathways, but promoting the activation of AKT, thus controlling cytokine storm and regulating immune balance. The present study demonstrated the multicomponent, multitarget, and multipathway characteristics of the QX1 formula and provided a novel understanding of the QX1 formula in the clinical application on cardiac dysfunction-related diseases.

Tyrosyl phosphorylation of PZR promotes hypertrophic cardiomyopathy in PTPN11-associated Noonan syndrome with multiple lentigines

Noonan syndrome with multiple lentigines (NSML) is a rare autosomal dominant disorder that presents with cardio-cutaneous-craniofacial defects. Hypertrophic cardiomyopathy (HCM) represents the major life-threatening presentation in NSML. Mutations in the PTPN11 gene that encodes for the protein tyrosine phosphatase (PTP), SHP2, represents the predominant cause of HCM in NSML. NSML-associated PTPN11 mutations render SHP2 catalytically inactive with an "open" conformation. NSML-associated PTPN11 mutations cause hypertyrosyl phosphorylation of the transmembrane glycoprotein, protein zero-related (PZR), resulting in increased SHP2 binding. Here we show that NSML mice harboring a tyrosyl phosphorylation-defective mutant of PZR (NSML/PZRY242F) that is defective for SHP2 binding fail to develop HCM. Enhanced AKT/S6 kinase signaling in heart lysates of NSML mice was reversed in NSML/PZRY242F mice, demonstrating that PZR/SHP2 interactions promote aberrant AKT/S6 kinase activity in NSML. Enhanced PZR tyrosyl phosphorylation in the hearts of NSML mice was found to drive myocardial fibrosis by engaging an Src/NF-κB pathway, resulting in increased activation of IL-6. Increased expression of IL-6 in the hearts of NSML mice was reversed in NSML/PZRY242F mice, and PZRY242F mutant fibroblasts were defective for IL-6 secretion and STAT3-mediated fibrogenesis. These results demonstrate that NSML-associated PTPN11 mutations that induce PZR hypertyrosyl phosphorylation trigger pathophysiological signaling that promotes HCM and cardiac fibrosis.

The role and function of IκKα/β in monocyte impairment

Following major trauma, sepsis or surgery, some patients exhibit an impaired monocyte inflammatory response that is characterized by a decreased response to a subsequent bacterial challenge. To investigate this poorly understood phenomenon, we adopted an in-vitro model of endotoxin tolerance utilising primary human CD14 + monocytes to focus on the effect of impairment on IκKα/β, a critical part of the NFκB pathway. Impaired monocytes had decreased IκKα mRNA and protein expression and decreased phosphorylation of the IκKα/β complex. The impaired monocyte secretome demonstrated a distinct cytokine/chemokine footprint from the naïve monocyte, and that TNF-α was the most sensitive cytokine or chemokine in this setting of impairment. Inhibition of IκKα/β with a novel selective inhibitor reproduced the impaired monocyte phenotype with decreased production of TNF-α, IL-6, IL-12p70, IL-10, GM-CSF, VEGF, MIP-1β, TNF-β, IFN-α2 and IL-7 in response to an LPS challenge. Surgical patients with infection also exhibited an impaired monocyte phenotype and had decreased SITPEC, TAK1 and MEKK gene expression, which are important for IκKα/β activation. Our results emphasize that impaired monocyte function is, at least in part, related to dysregulated IκKα/β activation, and that IκKα/β is likely involved in mounting a sufficient monocyte inflammatory response. Future studies may wish to focus on adjuvant therapies that augment IκKα/β function to restore monocyte function in this clinically important problem.

Vascular KATP channels protect from cardiac dysfunction and preserve cardiac metabolism during endotoxemia

Abstract

K_ATP channels in the vasculature composed of Kir6.1 regulate vascular tone and may contribute to the pathogenesis of endotoxemia. We used mice with cell-specific deletion of Kir6.1 in smooth muscle (smKO) and endothelium (eKO) to investigate this question. We found that smKO mice had a significant survival disadvantage compared with their littermate controls when treated with a sub-lethal dose of lipopolysaccharide (LPS). All cohorts of mice became hypotensive following bacterial LPS administration; however, mean arterial pressure in WT mice recovered to normal levels, whereas smKO struggled to overcome LPS-induced hypotension. In vivo and ex vivo investigations revealed pronounced cardiac dysfunction in LPS-treated smKO, but not in eKO mice. Similar results were observed in a cecal slurry injection model. Metabolomic profiling of hearts revealed significantly reduced levels of metabolites involved in redox/energetics, TCA cycle, lipid/fatty acid and amino acid metabolism. Vascular smooth muscle-localised K_ATP channels have a critical role in the response to systemic infection by normalising cardiac function and haemodynamics through metabolic homeostasis.

Key messages

• Mice lacking vascular K_ATP channels are more susceptible to death from infection.

• Absence of smooth muscle K_ATP channels depresses cardiac function during infection.

• Cardiac dysfunction is accompanied by profound changes in cellular metabolites.

• Findings from this study suggest a protective role for vascular K_ATP channels in response to systemic infection.

Electronic supplementary material

The online version of this article (10.1007/s00109-020-01946-3) contains supplementary material, which is available to authorized users.

A Comprehensive Review of Clinical Cardiotoxicity Incidence of FDA-Approved Small-Molecule Kinase Inhibitors

Numerous protein kinases encoded in the genome have become attractive targets for the treatment of different types of cancer. As of January 2020, a total of 52 small-molecule kinase inhibitors (SMKIs) have been approved by the FDA. With the numerous clinical trials and a heavy focus on drug safety, SMKI-induced cardiotoxicity, which is a life-threatening risk, has greatly attracted the attention of researchers. In this review, the SMKIs with cardiotoxicity incidence were described exhaustively. The data were collected from 42 clinical trials, 25 FDA-published documents, seven meta-analysis/systematic reviews, three case reports and more than 50 other types of articles. To date, 73% (38 of 52) of SMKIs have reported treatment-related cardiotoxicity. Among the 38 SMKIs with known cardiotoxicity, the rates of incidence of cardiac adverse events were QT prolongation: 47% (18 of 38), hypertension: 40% (15 of 38), left ventricular dysfunction: 34% (13 of 38), arrhythmia: 34% (13 of 38), heart failure: 26% (10 of 38) and ischemia or myocardial infarction: 29% (11 of 38). In the development process of novel SMKIs, more attention should be paid to balancing the treatment efficacy and the risk of cardiotoxicity. In preclinical drug studies, producing an accurate and reliable cardiotoxicity evaluation model is of key importance. To avoid the clinical potential cardiotoxicity risk and discontinuation of a highly effective drug, patients treated with SMKIs should be proactively monitored on the basis of a global standard. Moreover, the underlying mechanisms of SMKI-induced cardiotoxicity need to be further studied to develop new therapies for SMKI-induced cardiotoxicity.

Crocetin Attenuates Sepsis-Induced Cardiac Dysfunction via Regulation of Inflammatory Response and Mitochondrial Function

Sepsis-induced systemic inflammation can induce cardiac dysfunction, which can result in heart failure and death. Recently, natural drugs/compounds have received increased attention as therapeutic agents to prevent sepsis-induced cardiac dysfunction. Crocetin (CRO) is a natural compound that has been shown to reduce inflammation and cytotoxicity in cardiac ischemia/reperfusion injury. However, the effects of CRO on sepsis-induced cardiac dysfunction have not been evaluated. In this study, we used lipopolysaccharide (LPS)-induced H9c2 cells as an in vitro model to mimic cardiac sepsis. Crocetin significantly alleviated LPS-induced cytotoxicity, cellular apoptosis, and oxidative stress through increased Bcl-2 activity and PI3K-Akt signaling and suppression of caspase 3 and caspase 9 activities. Furthermore, CRO dramatically decreased the mRNA levels of TNF-α, IL-1, IL-6, and IL-8 via suppression of p65/Keap1 signaling and activation of Nrf2/HO-1/NQO1 signaling. In addition, CRO protected mitochondrial respiration, free fatty acid β-oxidation, and mitochondrial morphology in LPS-induced H9c2 cells. This study showed that CRO attenuated LPS-induced cardiac dysfunction via regulation of the inflammatory response and mitochondrial function and potentially had an effect on sepsis-induced cardiac dysfunction.

Therapeutic effects of IkB kinase inhibitor during systemic inflammation

Animal models of inflammatory diseases support the idea that nuclear factor κB (NF-κB) activation plays a pathophysiological role and is widely implicated in multiple organ dysfunction (MOD). Indeed, the inhibition of the IκB kinase (IKK) complex, involved in the NF-κB pathway, can represent a promising approach to prevent MOD. The present work employed a rat model of systemic inflammation to investigate the preventive effects of Inhibitor of IKK complex (IKK16). In male Wistar rats, systemic inflammation was induced by a tail vein injection of lipopolysaccharides (LPS challenge; 12 mg/kg). Treatment with IKK16 (1 mg/kg body weight) was administered, by tail vein, 15 min post-LPS. Age- and sex-matched healthy rats and LPS rats without treatment were used as controls. At 24 h post-IKK16 treatment, serum enzyme levels indicative of liver, kidney, pancreas and muscle function were evaluated by biochemical analysis, and RT-PCR technique was used to analyze gene expression of pro-inflammatory cytokines. Hemodynamic parameters were also considered to assess the LPS-induced inflammation. IKK16 treatment yielded a strong therapeutic effect in preventing LPS-induced elevation of serological enzyme levels, attenuating hepatic, renal, pancreatic and muscular dysfunction after LPS challenge. Moreover, as expected, LPS promoted a significantly overexpression of TNF-α, IL-6 and IL-1β in the heart, kidney, and liver; which was diminished by IKK16 treatment. The present study provides convincing evidence that selective inhibition of the IκB kinase complex through the action of IKK16, plays a protective role against LPS-induced multiple organ dysfunction by reducing the acute inflammatory response induced by endotoxin exposure.

Bruton's Tyrosine Kinase Inhibition Attenuates the Cardiac Dysfunction Caused by Cecal Ligation and Puncture in Mice

Sepsis is one of the most prevalent diseases in the world. The development of cardiac dysfunction in sepsis results in an increase of mortality. It is known that Bruton's tyrosine kinase (BTK) plays a role in toll-like receptor signaling and NLRP3 inflammasome activation, two key components in the pathophysiology of sepsis and sepsis-associated cardiac dysfunction. In this study we investigated whether pharmacological inhibition of BTK (ibrutinib 30 mg/kg and acalabrutinib 3 mg/kg) attenuates sepsis associated cardiac dysfunction in mice. 10-week old male C57BL/6 mice underwent CLP or sham surgery. One hour after surgery mice received either vehicle (5% DMSO + 30% cyclodextrin i.v.), ibrutinib (30 mg/kg i.v.), or acalabrutinib (3 mg/kg i.v.). Mice also received antibiotics and an analgesic at 6 and 18 h. After 24 h, cardiac function was assessed by echocardiography in vivo. Cardiac tissue underwent western blot analysis to determine the activation of BTK, NLRP3 inflammasome and NF-κB pathway. Serum analysis of 33 cytokines was conducted by a multiplex assay. When compared to sham-operated animals, mice subjected to CLP demonstrated a significant reduction in ejection fraction (EF), fractional shortening (FS), and fractional area change (FAC). The cardiac tissue from CLP mice showed significant increases of BTK, NF-κB, and NLRP3 inflammasome activation. CLP animals resulted in a significant increase of serum cytokines and chemokines (TNF-α, IL-6, IFN-γ, KC, eotaxin-1, eotaxin-2, IL-10, IL-4, CXCL10, and CXCL11). Delayed administration of ibrutinib and acalabrutinib attenuated the decline of EF, FS, and FAC caused by CLP and also reduced the activation of BTK, NF-κB, and NLRP3 inflammasome. Both ibrutinib and acalabrutinib significantly suppressed the release of cytokines and chemokines. Our study revealed that delayed intravenous administration of ibrutinib or acalabrutinib attenuated the cardiac dysfunction associated with sepsis by inhibiting BTK, reducing NF-κB activation and the activation of the inflammasome. Cytokines associated with sepsis were significantly reduced by both BTK inhibitors. Acalabrutinib is found to be more potent than ibrutinib and could potentially prove to be a novel therapeutic in sepsis. Thus, the FDA-approved BTK inhibitors ibrutinib and acalabrutinib may be repurposed for the use in sepsis.

Aging renders desynchronization between clock and immune genes in male Wistar rat kidney: chronobiotic role of curcumin

Suprachiasmatic nucleus (SCN) contains the central clock that orchestrate circadian rhythms in physiology and behavior in mammals. Tightly interlocked transcriptional and translational feedback loops (TTFLs) comprising of various clock genes such as Clock, Bmal1, Periods, Cryptochromes etc. in the SCN, send the timing signals to peripheral clocks that governs local metabolism with similar TTFLs. Peripheral clocks in kidney regulates several circadian rhythms like blood pressure, immunity etc. However, aging leads to circadian and inflammatory disorders in kidney. Though there are increasing evidences on age associated perturbations, studies elucidating the rhythmic expression of clock and immune genes across aging in kidney are obscure. We therefore studied changes in daily rhythms of clock and immune genes in kidney. In this study we measured mRNA expression of clock genes rBmal1, rPer1, rPer2, rCry1, rCry2, rRev-erbα, rRorα, and inflammatory genes rNfκb1, rTnfα, rIl6, rTlr4 and rTlr9 in 3, 12 and 24 months male Wistar rat kidney using qRT-PCR. From our study, we did not observe significant changes in clock genes expression except rRorα, but immune genes showed significant phase alterations as well as increase in mean 24 h levels. Pearson correlation analysis of data showed desynchronization between immune and clock genes expression. We further studied the effect of administration of curcumin which has anti-aging, anti-inflammatory, anti-oxidant etc. properties, and evaluated its chronobiotic properties. We here report differential effects of curcumin administration on daily rhythms of clock and immune genes expression.

Forebrain Cholinergic Signaling Regulates Innate Immune Responses and Inflammation

The brain regulates physiological functions integral to survival. However, the insight into brain neuronal regulation of peripheral immune function and the neuromediator systems and pathways involved remains limited. Here, utilizing selective genetic and pharmacological approaches, we studied the role of forebrain cholinergic signaling in the regulation of peripheral immune function and inflammation. Forebrain-selective genetic ablation of acetylcholine release and vagotomy abolished the suppression of serum TNF by the centrally-acting cholinergic drug galantamine in murine endotoxemia. Selective stimulation of acetylcholine action on the M1 muscarinic acetylcholine receptor (M1 mAChR) by central administration of the positive allosteric modulator benzyl quinolone carboxylic acid (BQCA) suppressed serum TNF (TNFα) levels in murine endotoxemia. This effect was recapitulated by peripheral administration of the compound. BQCA also improved survival in murine endotoxemia and these effects were abolished in M1 mAChR knockout (KO) mice. Selective optogenetic stimulation of basal forebrain cholinergic neurons innervating brain regions with abundant M1 mAChR localization reduced serum TNF in endotoxemic mice. These findings reveal that forebrain cholinergic neurons regulate innate immune responses and inflammation, suggesting the possibility that in diseases associated with cholinergic dysfunction, including Alzheimer's disease this anti-inflammatory regulation can be impaired. These results also suggest novel anti-inflammatory approaches based on targeting forebrain cholinergic signaling in sepsis and other disorders characterized by immune dysregulation.

Identification of AnnexinA1 as an Endogenous Regulator of RhoA, and Its Role in the Pathophysiology and Experimental Therapy of Type-2 Diabetes

Annexin A1 (ANXA1) is an endogenously produced anti-inflammatory protein, which plays an important role in the pathophysiology of diseases associated with chronic inflammation. We demonstrate that patients with type-2 diabetes have increased plasma levels of ANXA1 when compared to normoglycemic subjects. Plasma ANXA1 positively correlated with fatty liver index and elevated plasma cholesterol in patients with type-2 diabetes, suggesting a link between aberrant lipid handling, and ANXA1. Using a murine model of high fat diet (HFD)-induced insulin resistance, we then investigated (a) the role of endogenous ANXA1 in the pathophysiology of HFD-induced insulin resistance using ANXA1^−/− mice, and (b) the potential use of hrANXA1 as a new therapeutic approach for experimental diabetes and its microvascular complications. We demonstrate that: (1) ANXA1^−/− mice fed a HFD have a more severe diabetic phenotype (e.g., more severe dyslipidemia, insulin resistance, hepatosteatosis, and proteinuria) compared to WT mice fed a HFD; (2) treatment of WT-mice fed a HFD with hrANXA1 attenuated the development of insulin resistance, hepatosteatosis and proteinuria. We demonstrate here for the first time that ANXA1^−/− mice have constitutively activated RhoA. Interestingly, diabetic mice, which have reduced tissue expression of ANXA1, also have activated RhoA. Treatment of HFD-mice with hrANXA1 restored tissue levels of ANXA1 and inhibited RhoA activity, which, in turn, resulted in restoration of the activities of Akt, GSK-3β and endothelial nitric oxide synthase (eNOS) secondary to re-sensitization of IRS-1 signaling. We further demonstrate in human hepatocytes that ANXA1 protects against excessive mitochondrial proton leak by activating FPR2 under hyperglycaemic conditions. In summary, our data suggest that (a) ANXA1 is a key regulator of RhoA activity, which restores IRS-1 signal transduction and (b) recombinant human ANXA1 may represent a novel candidate for the treatment of T2D and/or its complications.

PFKFB3 promotes endotoxemia-induced myocardial dysfunction through inflammatory signaling and apoptotic induction

Cardiac dysfunction is a vital complication during endotoxemia (ETM). Accumulating evidence suggests that enhanced glycolytic metabolism promotes inflammatory and myocardial diseases. In this study, we performed deep mRNA sequencing analysis on the hearts of control and lipopolysaccharide (LPS)-challenged mice (40 mg/kg, i.p.) and identified that the glycolytic enzyme, 6-phosphofructo-2-kinase (PFK-2)/fructose-2,6-bisphosphatase 3 (PFKFB3) might play an indispensable role in ETM-induced cardiac damage. Quantitative real-time PCR validated the transcriptional upregulation of PFKFB3 in the myocardium of LPS-challenged mice and immunoblotting and immunostaining assays confirmed that LPS stimulation markedly increased the expression of PFKFB3 at the protein level both in vivo and in vitro. The potent antagonist 3-(3pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO) was used to block PFKFB3 activity in vivo (50 mg/kg, i.p.) and in vitro (10 μM). Echocardiographic analysis and TUNEL staining showed that 3PO significantly alleviated LPS-induced cardiac dysfunction and apoptotic injury in vivo. 3PO also suppressed the LPS-induced secretion of tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and lactate in the serum, in addition to lactate in the myocardium. PFKFB3 inhibition also diminished the nuclear translocation and phosphorylation of transcription factor nuclear factor-κB (NF-κB) in both adult cardiomyocytes and HL-1 cells. Furthermore, immunoblotting analysis showed that 3PO inhibited LPS-induced apoptotic induction in cardiomyocytes. Taken together, these findings demonstrate that PFKFB3 participates in LPS-induced cardiac dysfunction via mediating inflammatory and apoptotic signaling pathway.

Linagliptin Attenuates the Cardiac Dysfunction Associated With Experimental Sepsis in Mice With Pre-existing Type 2 Diabetes by Inhibiting NF-κB

The mortality rate of patients who develop sepsis-related cardiac dysfunction is high. Many disease conditions (e.g., diabetes) increase the susceptibility to infections and subsequently sepsis. Activation of the NF-κB pathway plays a crucial role in the pathophysiology of sepsis-associated cardiac dysfunction and diabetic cardiomyopathy. The effect of diabetes on outcomes in patients with sepsis is still highly controversial. We here hypothesized that type 2 diabetes (T2DM) augments the cardiac (organ) dysfunction associated with sepsis, and that inhibition of the NF-κB pathway with linagliptin attenuates the cardiac (organ) dysfunction in mice with T2DM/sepsis. To investigate this, 10-week old male C57BL/6 mice were randomized to receive normal chow or high fat diet (HFD), 60% of calories derived from fat). After 12 weeks, mice were subjected to sham surgery or cecal ligation and puncture (CLP) for 24 h. At 1 hour after surgery, mice were treated with linagliptin (10 mg/kg, i.v.), IKK-16 (1 mg/kg, i.v.), or vehicle (2% DMSO, 3 ml/kg, i.v.). Mice also received analgesia, fluids and antibiotics at 6 and 18 h after surgery. Mice that received HFD showed a significant increase in body weight, impairment in glucose tolerance, reduction in ejection fraction (%EF), and increase in alanine aminotransferase (ALT). Mice on HFD subjected to CLP showed further reduction in %EF, increase in ALT, developed acute kidney dysfunction and lung injury. They also showed significant increase in NF-κB pathway, iNOS expression, and serum inflammatory cytokines compared to sham surgery group. Treatment of HFD-CLP mice with linagliptin or IKK-16 resulted in significant reductions in (i) cardiac, liver, kidney, and lung injury associated with CLP-sepsis, (ii) NF-κB activation and iNOS expression in the heart, and (iii) serum inflammatory cytokine levels compared to HFD-CLP mice treated with vehicle. Our data show that pre-existing type 2 diabetes phenotype worsens the organ dysfunction/injury associated with CLP-sepsis in mice. Most notably, inhibition of NF-κB reduces the organ dysfunction/injury associated with sepsis in mice with pre-existing T2DM.

Synergistic interactions between NOD receptors and TLRs: Mechanisms and clinical implications

Interactions between pattern recognition receptors (PRRs) shape innate immune responses to particular classes of pathogens. Here, we review interactions between TLRs and nucleotide-binding oligomerization domain 1 and 2 (NOD1 and NOD2) receptors, two major groups of PRRs involved in innate recognition of bacteria. Most of experimental data both in vitro and in vivo suggest that NODs and TLRs synergize with each other at inducing the production of cytokines and antimicrobial peptides. Molecular mechanisms of this synergy remain poorly understood, although several scenarios can be proposed: (i) direct interactions of signaling pathways downstream of NODs and TLRs; (ii) mutual transcriptional regulation of unique components of NOD-dependent and TLR-dependent signaling pathways; and (iii) interactions at the post-transcriptional level. Potential practical implications of NOD-TLR synergy are dual. In sepsis, where synergistic effects probably contribute to excessive proinflammatory cytokine production, blockade of NOD1, and/or NOD2 in addition to TLR4 blockade may be required to achieve therapeutic benefit. On the other hand, synergistic combinations of relatively small doses of NOD and TLR agonists administered before infection could be used to boost innate resistance against bacterial pathogens.

A novel model of reno-cardiac syndrome in the C57BL/ 6 mouse strain

Background

The end stage renal disease population has a 20 fold higher incidence of cardiovascular mortality compared to the overall population. The development of reno-cardiac syndrome in these patients will result in cardiovascular events to be the cause of 50% of fatalities. There is therefore a need to research improved therapeutic strategies to combat renal cardiac pathologies. Murine in vivo models contribute greatly to such research allowing for specific genetic modification and reduced miscellany, however there is currently no reliable model of reno-cardiac syndrome in the most common genetically modified mouse strain, the C57BL/6. In this study we have manipulated an established model of chronic renal disease using adenine infused diet and prolonged the course of its pathology achieving chronic renal failure and subsequent reno-cardiac syndrome in the C57BL/6 mouse.

Methods

Eight week-old male C57BL/ 6 mice were acclimatised for 7 days before administration of a 0.15% adenine diet or control diet for 20 weeks.

Cardiac function was assessed in mice at week 20 by echocardiography. At experiment termination blood and urine samples were analysed biochemically and organ dysfunction/injury was determined using immunoblotting and immunohistochemistry.

Results

Administration of 0.15% adenine diet caused progressive renal failure resulting in reno-cardiac syndrome. At endpoint uraemia was confirmed by blood biochemistry which in the adenine fed mice showed significant increases in serum creatinine, urea, calcium (P < 0.0001) potassium (P < 0.05), and a significantly reduced glomerular filtration rate (P < 0.05). Reno-cardiac syndrome was confirmed by a significantly increased heart to body weight ratio (P < 0.0001) and echocardiography which showed significant reductions in percentage of ejection fraction, fractional shortening, fractional area change, (P < 0.0001) and an increase in left ventricular end diastolic volume (P < 0.05). Immunoblotting of kidney and heart tissue showed increased apoptosis (caspase 3) and fibrosis (fibronectin) and increases in the cardiac levels of phosphorylated Akt, and renal total Akt. Immunohistochemistry for α-SMA, collagen 1 and collagen 3 further confirmed fibrosis.

Conclusions

We present a novel regimen of adenine diet which induces both chronic kidney disease and reno-cardiac syndrome in the C57/BL6 mouse strain. The non-surgical nature of this model makes it highly reproducible compared to other models currently available.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1155-3) contains supplementary material, which is available to authorized users.

Protective role of down-regulated microRNA-31 on intestinal barrier dysfunction through inhibition of NF-κB/HIF-1α pathway by binding to HMOX1 in rats with sepsis

Background

Intestinal barrier dysfunction is a significant clinical problem, commonly developing in a variety of acute or chronic pathological conditions. Herein, we evaluate the effect of microRNA-31 (miR-31) on intestinal barrier dysfunction through NF-κB/HIF-1α pathway by targeting HMOX1 in rats with sepsis.

Methods

Male Sprague-Dawley rats were collected and divided into the sham group, and the cecum ligation and perforation group which was subdivided after CACO-2 cell transfection of different mimic, inhibitor, or siRNA. Levels of serum D-lactic acid, diamine oxidase and fluorescence isothiocyanate dextran, FITC-DX concentration, and bacterial translocation were detected. Superoxidedismutase (SOD) activity and malondialdehyde (MDA) content were evaluated using the colorimetric method and an automatic microplate reader, respectively. Additionally, the levels of tumor necrosis factor, interleukin (IL)-6, and IL-10 were tested using enzyme-linked immunosorbent assay. The expression of miR-31, HMOX1, NF-κB, HIF-1α, IκB, ZO-1 and Occludin were assessed by reverse transcription quantitative polymerase chain reaction and Western blot analysis.

Results

Inhibition of miR-31 decreased intestinal mucosal permeability and intestinal barrier function. The increased levels of miR-31 could cause oxidative damage and affect the expression of inflammatory factors in intestinal tissue of rats. HMOX1 was confirmed as a target gene of miR-31. MiR-31 affected intestinal mucosal permeability and intestinal barrier function, as well as oxidative damage and inflammation level by regulating HMOX1. Down-regulation of miR-31 inhibited NF-κB/HIF-1α pathway related genes by regulating HMOX1 expression. Furthermore, inhibition of miR-31 increased survival rates of rats.

Conclusion

Overall, the current study found that inhibition of miR-31 protects against intestinal barrier dysfunction through suppression of the NF-κB/HIF-1α pathway by targeting HMOX1 in rats with sepsis.

Effects of Glycyrrhizin on the Differentiation of Myeloid Cells of the Heart and Lungs in Lipopolysaccharide-Induced Septic Mice

BACKGROUND

This study investigated the effects of glycyrrhizin (GR) on the ratio of myeloid-derived suppressor cells (MDSCs) to cluster of differentiation (CD)11b+Gr1 myeloid cells in the heart and lungs in lipopolysaccharide (LPS)-induced septic mice.

METHODS

Mice were divided into three groups: Control, LPS, and LPS+GR. After intraperitoneal injection of phosphate-buffered saline for the Control group, LPS for the LPS group, and a combination of LPS and GR for the LPS+GR group, fluorescence-activated cell sorting was utilized to evaluate cytokines and immune cells in the blood, heart, and lungs. Histopathologic analysis of Toll-like receptor (TLR)4 was also performed.

RESULTS

The cytokine amounts in the LPS and LPS+GR groups were significantly higher than in the Control group; however, that in the LPS+GR group was significant lower than in the LPS group. The ratio of MDSCs to CD11b+Gr1 myeloid cells in the LPS+GR group was significantly higher than in the LPS group but was significantly lower than in the Control group. The staining intensity of TLR4 showed the same pattern as that of cytokines in the heart and lungs. TLR4 staining was significantly lower in the LPS+GR group than in the LPS group but was higher than that in the Control group.

CONCLUSION

GR exhibited protective effects on the heart and lungs in LPS-induced septic mice. The effects were associated with an elevated ratio of MDSCs to CD11b+Gr1 myeloid cells and the inhibition of cytokine release and TLR4 expression after GR injection.

LCZ696 (Sacubitril/Valsartan), an Angiotensin-Receptor Neprilysin Inhibitor, Attenuates Cardiac Hypertrophy, Fibrosis, and Vasculopathy in a Rat Model of Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is associated with cardiac hypertrophy, fibrosis, and increased risk of cardiovascular mortality. LCZ696 (sacubitril/valsartan) is a promising agent that has shown significant potential in treatment of heart failure. We hypothesized that LCZ696 is more effective than valsartan alone in the treatment of cardiovascular abnormalities associated with experimental CKD.

METHODS AND RESULTS

Male Sprague-Dawley rats underwent 5/6 nephrectomy and were subsequently randomized to no treatment (CKD), 30 mg/kg valsartan (VAL), or 60 mg/kg LCZ696 (LCZ). After 8 weeks, cardiovascular parameters, including markers of inflammation, oxidative stress, mitochondrial abundance/function, hypertrophy, and fibrosis, were measured. Treatment with LCZ resulted in significant improvements in the heart-body weight ratio and serum concentrations of N-terminal pro-B-type natriuretic peptide and fibroblast growth factor 23 along with improvement of kidney function. In addition, LCZ ameliorated aortic fibrosis and cardiac hypertrophy and fibrosis, reduced markers of cardiac oxidative stress and inflammation, and improved indicators of mitochondrial mass/function. Although VAL also improved some of these indices, treatment with LCZ was more effective than VAL alone.

CONCLUSIONS

CKD-associated cardiovascular abnormalities, including myocardial hypertrophy, fibrosis, inflammation, oxidative stress, and mitochondrial depletion/dysfunction, were more effectively attenuated by LCZ treatment than by VAL alone.

Endogenously generated arachidonate-derived ligands for TRPV1 induce cardiac protection in sepsis

The severity of cardiac dysfunction predicts mortality in sepsis. Activation of transient receptor potential vanilloid receptor type (TRPV)-1, a predominantly neuronal nonselective cation channel, has been shown to improve outcome in sepsis and endotoxemia. However, the role of TRPV1 and the identity of its endogenous ligands in the cardiac dysfunction caused by sepsis and endotoxemia are unknown. Using TRPV1^-/- and TRPV1^+/+ mice, we showed that endogenous activation of cardiac TRPV1 during sepsis is key to limiting the ensuing cardiac dysfunction. Use of liquid chromatography-tandem mass spectrometry lipid analysis and selective inhibitors of arachidonic metabolism suggest that the arachidonate-derived TRPV1 activator, 20-hydroxyeicosateraenoic acid (20-HETE), underlies a substantial component of TRPV1-mediated cardioprotection in sepsis. Moreover, using selective antagonists for neuropeptide receptors, we show that this effect of TRPV1 relates to the activity of neuronally released cardiac calcitonin gene-related peptide (CGRP) and that, accordingly, administration of CGRP can rescue cardiac dysfunction in severe endotoxemia. In sum activation of TRPV1 by 20-HETE leads to the release of CGRP, which protects the heart against the cardiac dysfunction in endotoxemia and identifies both TRPV1 and CGRP receptors as potential therapeutic targets in endotoxemia.-Chen, J., Hamers, A. J. P., Finsterbusch, M., Massimo, G., Zafar, M., Corder, R., Colas, R. A., Dalli, J., Thiemermann, C., Ahluwalia, A. Endogenously generated arachidonate-derived ligands for TRPV1 induce cardiac protection in sepsis.

Annexin A1 attenuates microvascular complications through restoration of Akt signalling in a murine model of type 1 diabetes

AIMS/HYPOTHESIS

Microvascular complications in the heart and kidney are strongly associated with an overall rise in inflammation. Annexin A1 (ANXA1) is an endogenous anti-inflammatory molecule that limits and resolves inflammation. In this study, we have used a bedside to bench approach to investigate: (1) ANXA1 levels in individuals with type 1 diabetes; (2) the role of endogenous ANXA1 in nephropathy and cardiomyopathy in experimental type 1 diabetes; and (3) whether treatment with human recombinant ANXA1 attenuates nephropathy and cardiomyopathy in a murine model of type 1 diabetes.

METHODS

ANXA1 was measured in plasma from individuals with type 1 diabetes with or without nephropathy and healthy donors. Experimental type 1 diabetes was induced in mice by injection of streptozotocin (STZ; 45 mg/kg i.v. per day for 5 consecutive days) in C57BL/6 or Anxa1 ^-/- mice. Diabetic mice were treated with human recombinant (hr)ANXA1 (1 μg, 100 μl, 50 mmol/l HEPES; 140 mmol/l NaCl; pH 7.4, i.p.) or vehicle (100 μl, 50 mmol/l HEPES; 140 mmol/l NaCl; pH 7.4, i.p.).

RESULTS

Plasma levels of ANXA1 were elevated in individuals with type 1 diabetes with/without nephropathy compared with healthy individuals (66.0 ± 4.2/64.0 ± 4 ng/ml vs 35.9 ± 2.3 ng/ml; p < 0.05). Compared with diabetic wild-type (WT) mice, diabetic Anxa1 ^-/- mice exhibited a worse diabetic phenotype and developed more severe cardiac (ejection fraction; 76.1 ± 1.6% vs 49.9 ± 0.9%) and renal dysfunction (proteinuria; 89.3 ± 5.0 μg/mg vs 113.3 ± 5.5 μg/mg). Mechanistically, compared with non-diabetic WT mice, the degree of the phosphorylation of mitogen-activated protein kinases (MAPKs) p38, c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) was significantly higher in non-diabetic Anxa1 ^-/- mice in both the heart and kidney, and was further enhanced after STZ-induced type 1 diabetes. Prophylactic treatment with hrANXA1 (weeks 1-13) attenuated both cardiac (ejection fraction; 54.0 ± 1.6% vs 72.4 ± 1.0%) and renal (proteinuria; 89.3 ± 5.0 μg/mg vs 53.1 ± 3.4 μg/mg) dysfunction associated with STZ-induced diabetes, while therapeutic administration of hrANXA1 (weeks 8-13), after significant cardiac and renal dysfunction had already developed, halted the further functional decline in cardiac and renal function seen in diabetic mice administered vehicle. In addition, administration of hrANXA1 attenuated the increase in phosphorylation of p38, JNK and ERK, and restored phosphorylation of Akt in diabetic mice.

CONCLUSIONS/INTERPRETATION

Overall, these results demonstrate that ANXA1 plasma levels are elevated in individuals with type 1 diabetes independent of a significant impairment in renal function. Furthermore, in mouse models with STZ-induced type 1 diabetes, ANXA1 protects against cardiac and renal dysfunction by returning MAPK signalling to baseline and activating pro-survival pathways (Akt). We propose ANXA1 to be a potential therapeutic option for the control of comorbidities in type 1 diabetes.

The effect of IκK-16 on lipopolysaccharide-induced impaired monocytes

This study focuses on impaired monocyte function, which occurs in some patients after trauma, major elective surgery, or sepsis. This monocyte impairment increases the risk of secondary infection and death. We aimed to determine the influence IκK-16 had on monocytes using an ex-vivo model of human monocyte impairment. We included the effects of the well-studied comparators interferon-gamma (IFN-γ) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on impaired monocytes. Primary human monocytes were stimulated with 10ng/mL of lipopolysaccharide (LPS) for 16h and then challenged with 100ng/mL LPS to assess the monocyte inflammatory response. Treatment regimens, consisting of either IκK-16, IFN-γ, or GM-CSF, were administered to impaired monocytes near the time of initial LPS stimulation. Stimulation with 10ng/mL LPS initially promoted a pro-inflammatory response but subsequently impaired production of both tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) and decreased HLA-DR expression. IκK-16 treatment attenuated TNF-α production and programmed death-ligand 1 (PD-L1) expression and increased IL-10 and CD14 expression. IFN-γ treatment increased TNF-α production as well as PD-L1 and HLA-DR expression. In conclusion, limiting early inflammation with IκK-16 suppresses TNF-α production and PD-L1 expression but enhances IL-10 production and preserves CD14 expression for potential future exposure to infective stimuli.

IκK-16 decreases miRNA-155 expression and attenuates the human monocyte inflammatory response

Excessive inflammatory responses in the surgical patient may result in cellular hypo-responsiveness, which is associated with an increased risk of secondary infection and death. microRNAs (miRNAs), such as miR-155, are powerful regulators of inflammatory signalling pathways including nuclear factor κB (NFκB). Our objective was to determine the effect of IκK-16, a selective blocker of inhibitor of kappa-B kinase (IκK), on miRNA expression and the monocyte inflammatory response. In a model of endotoxin tolerance using primary human monocytes, impaired monocytes had decreased p65 expression with suppressed TNF-α and IL-10 production (P < 0.05). miR-155 and miR-138 levels were significantly upregulated at 17 h in the impaired monocyte (P < 0.05). Notably, IκK-16 decreased miR-155 expression with a corresponding dose-dependent decrease in TNF-α and IL-10 production (P < 0.05), and impaired monocyte function was associated with increased miR-155 and miR-138 expression. In the context of IκK-16 inhibition, miR-155 mimics increased TNF-α production, while miR-155 antagomirs decreased both TNF-α and IL-10 production. These data demonstrate that IκK-16 treatment attenuates the monocyte inflammatory response, which may occur through a miR-155-mediated mechanism, and that IκK-16 is a promising approach to limit the magnitude of an excessive innate inflammatory response to LPS.

Inhibition of IκB Kinase at 24 Hours After Acute Kidney Injury Improves Recovery of Renal Function and Attenuates Fibrosis

Background

Acute kidney injury (AKI) is a major risk factor for the development of chronic kidney disease. Nuclear factor‐κB is a nuclear transcription factor activated post‐ischemia, responsible for the transcription of proinflammatory proteins. The role of nuclear factor‐κB in the renal fibrosis post‐AKI is unknown.

Methods and Results

We used a rat model of AKI caused by unilateral nephrectomy plus contralateral ischemia (30 minutes) and reperfusion injury (up to 28 days) to show impairment of renal function (peak: 24 hours), activation of nuclear factor‐κB (peak: 48 hours), and fibrosis (28 days). In humans, AKI is diagnosed by a rise in serum creatinine. We have discovered that the IκB kinase inhibitor IKK16 (even when given at peak serum creatinine) still improved functional and structural recovery and reduced myofibroblast formation, macrophage infiltration, transforming growth factor‐β expression, and Smad2/3 phosphorylation. AKI resulted in fibrosis within 28 days (Sirius red staining, expression of fibronectin), which was abolished by IKK16. To confirm the efficacy of IKK16 in a more severe model of fibrosis, animals were subject to 14 days of unilateral ureteral obstruction, resulting in tubulointerstitial fibrosis, myofibroblast formation, and macrophage infiltration, all of which were attenuated by IKK16.

Conclusions

Inhibition of IκB kinase at peak creatinine improves functional recovery, reduces further injury, and prevents fibrosis.

Emodin Combined with Nanosilver Inhibited Sepsis by Anti-inflammatory Protection

Background: Emodin is the main active component of rhubarb, which has demonstrated many beneficial effects against inflammation. Nanosilver is an effective antimicrobial agent. The present study was designed to observe the effects of Emodin combined with silver nanoparticles (E/S) on sepsis protection and related mechanism.

Methods: E/S was prepared by loading different concentrations of Emodin on nanosilver and cytotoxicity of E/S were determined by suphorhodamine B assays. Anti-microbial activities of E/S were assayed by direct interaction with various common pathogens and anti-adhesive activites of E/S on leukocytes with endothelial cells were assayed by biochemical analysis. Next, inflammatory cell enumeration, inflammatory mediators in bronchoalveolar lavage fluid (BALF) and endothelial cell function were analyzed on a clinically relevant model of sepsis induced by cecal ligation and puncture (CLP) after E/S administration. The effects of E/S on NF-κB and p38 were also examined by western blot.

Results: E/S exhibited little cytotoxicity action on endothelial cells and significant inhibitory activities against all tested common microorganisms and adherence between leukocyte and endothelial cells. E/S induced anti-sepsis protection mainly mediated by inhibition of inflammatory cells infiltration, down-regulation of TNF-alpha, IL-8 and lactic dehydrogenase (LDH), and inhibition of NF-κB and p38 pathways in mice 24 h post-CLP.

Conclusion: Our data suggest that E/S has strong anti-sepsis effects, which was related with anti-inflammatory protection and thereby promote survival following sepsis challenge.