Hypoxia/ischemia promotes CXCL10 expression in cardiac microvascular endothelial cells by NFkB activation

Islet-Resident Memory T Cells Orchestrate the Immunopathogenesis of Type 1 Diabetes through the FABP4-CXCL10 Axis

Type 1 diabetes (T1D) is a chronic disease characterized by self-destruction of insulin-producing pancreatic β cells by cytotoxic T cell activity. However, the pathogenic mechanism of T cell infiltration remains obscure. Recently, tissue-resident memory T (TRM) cells have been shown to contribute to cytotoxic T cell recruitment. TRM cells are found present in human pancreas and are suggested to modulate immune homeostasis. Here, the role of TRM cells in the development of T1D is investigated. The presence of TRM cells in pancreatic islets is observed in non-obese diabetic (NOD) mice before T1D onset. Mechanistically, elevated fatty acid-binding protein 4 (FABP4) potentiates the survival and alarming function of TRM cells by promoting fatty acid utilization and C-X-C motif chemokine 10 (CXCL10) secretion, respectively. In NOD mice, genetic deletion of FABP4 or depletion of TRM cells using CD69 neutralizing antibodies resulted in a similar reduction of pancreatic cytotoxic T cell recruitment, a delay in diabetic incidence, and a suppression of CXCL10 production. Thus, targeting FABP4 may represent a promising therapeutic strategy for T1D.

Morus alba L. (Sangzhi) alkaloids mitigate atherosclerosis by regulating M1/M2 macrophage polarization

BACKGROUND

Atherosclerosis (AS) is an important cause of cardiovascular disease, posing a substantial health risk. Recognized as a chronic inflammatory disorder, AS hinges on the pivotal involvement of macrophages in arterial inflammation, participating in its formation and progression. Sangzhi alkaloid (SZ-A) is a novel natural alkaloid extracted from the mulberry branches, has extensive pharmacological effects and stable pharmacokinetic characteristics. However, the effects and mechanisms of SZ-A on AS remain unclear.

PURPOSE

To explore the effect and underlying mechanisms of SZ-A on inflammation mediated by macrophages and its role in AS development.

METHODS

Atherosclerosis was induced in vivo in apolipoprotein E-deficient mice through a high-fat and high-choline diet. We utilized macrophages and vascular endothelial cells to investigate the effects of SZ-A on macrophage polarization and its anti-inflammatory properties on endothelial cells in vitro. The transcriptomic analyses were used to investigate the major molecule that mediates cell-cell interactions and the antiatherogenic mechanisms of SZ-A based on AS, subsequently validated in vivo and in vitro.

RESULTS

SZ-A demonstrated a significant inhibition in vascular inflammation and alleviation of AS severity by mitigating macrophage infiltration and modulating M1/M2 macrophage polarization in vitro and in vivo. Moreover, SZ-A effectively reduced the release of the proinflammatory mediator C-X-C motif chemokine ligand (CXCL)-10, predominantly secreted by M1 macrophages. This reduction in CXCL-10 contributed to improved endothelial cell function, reduced recruitment of additional macrophages, and inhibited the inflammatory amplification effect. This ultimately led to the suppression of atherogenesis.

CONCLUSION

SZ-A exhibited potent anti-inflammatory effects by inhibiting macrophage-mediated inflammation, providing a new therapeutic avenue against AS. This is the first study demonstrating the efficacy of SZ-A in alleviating AS severity and offers novel insights into its anti-inflammatory mechanism.

Association between choroidal thickness and interstitial lung disease in patients with rheumatoid arthritis: A cross-sectional study

Objectives

This study aimed to evaluate choroidal thickness (CT) in patients with rheumatoid arthritis (RA) and healthy controls and to determine its relationship with RA-associated interstitial lung disease (RA-ILD).

Patients and methods

A total of 63 patients with RA and 36 age- and sex-matched healthy controls were recruited in the cross-sectional study. Serological findings, Disease Activity Score-28, disease duration, and medical treatment of patients were recorded. Patients with RA were subdivided into two groups: patients with RA-ILD (Group 1) and patients with RA but without ILD (RA-noILD; Group 2). CTs were measured using enhanced depth imaging optical coherence tomography. CT was measured at five points: the subfoveal region, 750 μm nasal and temporal to the fovea, 1500 μm nasal and temporal to the fovea. Patients with RA-ILD were evaluated with delta high-resolution computed tomography (ΔHRCT) and pulmonary function test to determine the severity of interstitial lung disease.

Results

Four of 63 RA patients were excluded due to comorbidities. Thus, 59 RA patients, 20 in the RA-ILD group and 39 in the RA-noILD group, were included in the analyses. The RA groups were similar in terms of clinical characteristics and laboratory findings. There were statistically significant differences between Group 1, Group 2 and healthy controls (Group 3) compared to all CT values (p<0.05). The mean CT measured at 750 μm and 1500 μm nasal to the fovea was lowest in the RA-ILD group, followed by the RA-noILD and healthy groups (p<0.05). CT measurements did not correlate with the pulmonary function test and ΔHRCT.

Conclusion

RA-ILD patients had a thinner CT measured at nasal points. However, there was no association between CT measurements and the severity of ILD.

Immune urinary biomarkers predict infant cardiac surgery-associated acute kidney injury

BACKGROUND

Acute kidney injury (AKI) occurs frequently after infant cardiac surgery and is associated with poor outcomes, including mortality and prolonged length of stay. AKI mechanisms are poorly understood, limiting therapeutic targets. Emerging data implicates dysregulated immune activation in post-cardiac surgery AKI development. We sought to identify immune-mediated AKI biomarkers after infant cardiopulmonary bypass (CPB)-assisted cardiac surgery.

METHODS

A single-center prospective study of 126 infants less than 1 year old undergoing CPB-assisted surgery enrolled between 10/2017 and 6/2019. Urine samples were collected before CPB and at 6, 24, 48, and 72 h after surgery. Immune-mediated biomarkers were measured using commercial ELISA and Luminex™ multiplex kits. Based on subject age, neonatal KDIGO (< 1 month) or KDIGO criteria defined AKI. The Kruskal-Wallis rank test determined the relationship between urinary biomarker measurements and AKI.

RESULTS

A total of 35 infants (27%) developed AKI. AKI subjects were younger, underwent more complex surgery, and had longer CPB time. Subjects with AKI vs. those without AKI had higher median urinary chemokine 10 (C-X-C motif) ligand levels at 24, 48, and 72 h, respectively: 14.3 pg/ml vs. 5.3 pg/ml, 3.4 pg/ml vs. 0.8 pg/ml, and 1.15 pg/ml vs. 0.22 pg/ml (p < 0.05) post-CPB. At 6 h post-CPB, median vascular cell adhesion protein 1 (VCAM) levels (pg/mL) were higher among AKI subjects (491 pg/ml vs. 0 pg/ml, p = 0.04).

CONCLUSIONS

Urinary CXCL10 and VCAM are promising pro-inflammatory biomarkers for early AKI detection and may indicate eventual AKI therapeutic targets. A higher resolution version of the Graphical abstract is available as Supplementary information.

Extracellular derivatives for bone metabolism

BACKGROUND

Bone metabolism can maintain the normal homeostasis and function of bone tissue. Once the bone metabolism balance is broken, it will cause osteoporosis, osteoarthritis, bone defects, bone tumors, or other bone diseases. However, such orthopedic diseases still have many limitations in clinical treatment, such as drug restrictions, drug tolerance, drug side effects, and implant rejection.

AIM OF REVIEW

In complex bone therapy and bone regeneration, extracellular derivatives have become a promising research focus to solve the problems of bone metabolic diseases. These derivatives, which include components such as extracellular matrix, growth factors, and extracellular vesicles, have significant therapeutic potential. It has the advantages of good biocompatibility, low immune response, and dynamic demand for bone tissue. The purpose of this review is to provide a comprehensive perspective on extracellular derivatives for bone metabolism and elucidate the intrinsic properties and versatility of extracellular derivatives. Further discussion of them as innovative advanced orthopedic materials for improving the effectiveness of bone therapy and regeneration processes.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this review, we first listed the types and functions of three extracellular derivatives. Then, we discussed the effects of extracellular derivatives of different cell sources on bone metabolism. Subsequently, we collected applications of extracellular derivatives in the treatment of bone metabolic diseases and summarized the advantages and challenges of extracellular derivatives in clinical applications. Finally, we prospected the extracellular derivatives in novel orthopedic materials and clinical applications. We hope that the comprehensive understanding of extracellular derivatives in bone metabolism will provide new solutions to bone diseases.

SARS-CoV-2 Infection to Premature Neuronal Aging and Neurodegenerative Diseases: Is there any Connection with Hypoxia?

The pandemic of coronavirus disease-2019 (COVID-19), caused by SARS-CoV-2, has become a global concern as it leads to a spectrum of mild to severe symptoms and increases death tolls around the world. Severe COVID-19 results in acute respiratory distress syndrome, hypoxia, and multi- organ dysfunction. However, the long-term effects of post-COVID-19 infection are still unknown. Based on the emerging evidence, there is a high possibility that COVID-19 infection accelerates premature neuronal aging and increases the risk of age-related neurodegenerative diseases in mild to severely infected patients during the post-COVID period. Several studies correlate COVID-19 infection with neuronal effects, though the mechanism through which they contribute to the aggravation of neuroinflammation and neurodegeneration is still under investigation. SARS-CoV-2 predominantly targets pulmonary tissues and interferes with gas exchange, leading to systemic hypoxia. The neurons in the brain require a constant supply of oxygen for their proper functioning, suggesting that they are more vulnerable to any alteration in oxygen saturation level that results in neuronal injury with or without neuroinflammation. We hypothesize that hypoxia is one of the major clinical manifestations of severe SARS-CoV-2 infection; it directly or indirectly contributes to premature neuronal aging, neuroinflammation, and neurodegeneration by altering the expression of various genes responsible for the survival of the cells. This review focuses on the interplay between COVID-19 infection, hypoxia, premature neuronal aging, and neurodegenerative diseases and provides a novel insight into the molecular mechanisms of neurodegeneration.

ANGPTL2 promotes immune checkpoint inhibitor-related murine autoimmune myocarditis

Use of immune checkpoint inhibitors (ICIs) as cancer immunotherapy advances rapidly in the clinic. Despite their therapeutic benefits, ICIs can cause clinically significant immune-related adverse events (irAEs), including myocarditis. However, the cellular and molecular mechanisms regulating irAE remain unclear. Here, we investigate the function of Angiopoietin-like protein 2 (ANGPTL2), a potential inflammatory mediator, in a mouse model of ICI-related autoimmune myocarditis. ANGPTL2 deficiency attenuates autoimmune inflammation in these mice, an outcome associated with decreased numbers of T cells and macrophages. We also show that cardiac fibroblasts express abundant ANGPTL2. Importantly, cardiac myofibroblast-derived ANGPTL2 enhances expression of chemoattractants via the NF-κB pathway, accelerating T cell recruitment into heart tissues. Our findings suggest an immunostimulatory function for ANGPTL2 in the context of ICI-related autoimmune inflammation and highlight the pathophysiological significance of ANGPTL2-mediated cardiac myofibroblast/immune cell crosstalk in enhancing autoimmune responses. These findings overall provide insight into mechanisms regulating irAEs.

Effector T cell chemokine IP-10 predicts cardiac recovery and clinical outcomes post-myocardial infarction

Background and aims

Preclinical data suggest that activation of the adaptive immune system is critical for myocardial repair processes in acute myocardial infarction. The aim of the present study was to determine the clinical value of baseline effector T cell chemokine IP-10 blood levels in the acute phase of ST-segment elevation myocardial infarction (STEMI) for the prediction of the left ventricular function changes and cardiovascular outcomes after STEMI.

Methods

Serum IP-10 levels were retrospectively quantified in two independent cohorts of STEMI patients undergoing primary percutaneous coronary intervention.

Results

We report a biphasic response of the effector T cell trafficking chemokine IP-10 characterized by an initial increase of its serum levels in the acute phase of STEMI followed by a rapid reduction at 90min post reperfusion. Patients at the highest IP-10 tertile presented also with more CD4 effector memory T cells (CD4 TEM cells), but not other T cell subtypes, in blood. In the Newcastle cohort (n=47), patients in the highest IP-10 tertile or CD4 TEM cells at admission exhibited an improved cardiac systolic function 12 weeks after STEMI compared to patients in the lowest IP-10 tertile. In the Heidelberg cohort (n=331), STEMI patients were followed for a median of 540 days for major adverse cardiovascular events (MACE). Patients presenting with higher serum IP-10 levels at admission had a lower risk for MACE after adjustment for traditional risk factors, CRP and high-sensitivity troponin-T levels (highest vs. rest quarters: HR [95% CI]=0.420 [0.218-0.808]).

Conclusion

Increased serum levels of IP-10 in the acute phase of STEMI predict a better recovery in cardiac systolic function and less adverse events in patients after STEMI.

Network pharmacology-based approach to explore the underlying mechanism of sinomenine on sepsis-induced myocardial injury in rats

Background: Sepsis, a systemic disease, usually induces myocardial injury (MI), and sepsis-induced MI has become a significant contributor to sepsis-related deaths in the intensive care unit. The objective of this study is to investigate the role of sinomenine (SIN) on sepsis-induced MI and clarify the underlying mechanism based on the techniques of network pharmacology. Methods: Cecum ligation and puncture (CLP) was adopted to induce sepsis in male Sprague-Dawley (SD) rats. Serum indicators, echocardiographic cardiac parameters, and hematoxylin and eosin (H&E) staining were conducted to gauge the severity of cardiac damage. The candidate targets and potential mechanism of SIN against sepsis-induced MI were analyzed via network pharmacology. Enzyme-linked immunosorbent assay was performed for detecting the serum concentration of inflammatory cytokines. Western blot was applied for evaluating the levels of protein expression. Terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling assay was applied to assess cardiomyocyte apoptosis. Results: SIN significantly improved the cardiac functions, and attenuated myocardial structural damage of rats as compared with the CLP group. In total, 178 targets of SIN and 945 sepsis-related genes were identified, and 33 overlapped targets were considered as candidate targets of SIN against sepsis. Enrichment analysis results demonstrated that these putative targets were significantly associated with the Interleukin 17 (IL-17) signal pathway, inflammatory response, cytokines-mediated signal pathway, and Janus Kinase-Signal Transducers and Activators of Transcription (JAK-STAT) pathway. Molecular docking suggested that SIN had favorable binding affinities with Mitogen-Activated Protein Kinase 8 (MAPK8), Janus Kinase 1 (JAK1), Janus Kinase 2 (JAK2), Signal Transducer and Activator of Transcription 3 (STAT3), and nuclear factor kappa-B (NF-κB). SIN significantly reduced the serum concentration of Tumor Necrosis Factor-α (TNF-α), Interleukin 1 Beta (IL-1β), Interleukin 6 (IL-6), Interferon gamma (IFN-γ), and C-X-C Motif Chemokine Ligand 8 (CXCL8), lowered the protein expression of phosphorylated c-Jun N-terminal kinase 1 (JNK1), JAK1, JAK2, STAT3, NF-κB, and decreased the proportion of cleaved-caspase3/caspase3. In addition, SIN also significantly inhibited the apoptosis of cardiomyocytes as compared with the CLP group. Conclusion: Based on network pharmacology analysis and corresponding experiments, it was concluded that SIN could mediate related targets and pathways to protect against sepsis-induced MI.

Anoxia Rapidly Induces Changes in Expression of a Large and Diverse Set of Genes in Endothelial Cells

Sinusoidal endothelial cells are the predominant vascular surface of the bone marrow and constitute the functional hematopoietic niche where hematopoietic stem and progenitor cells receive cues for self-renewal, survival, and differentiation. In the bone marrow hematopoietic niche, the oxygen tension is usually very low, and this condition affects stem and progenitor cell proliferation and differentiation and other important functions of this region. Here, we have investigated in vitro the response of endothelial cells to a marked decrease in O2 partial pressure to understand how the basal gene expression of some relevant biological factors (i.e., chemokines and interleukins) that are fundamental for the intercellular communication could change in anoxic conditions. Interestingly, mRNA levels of CXCL3, CXCL5, and IL-34 genes are upregulated after anoxia exposure but become downmodulated by sirtuin 6 (SIRT6) overexpression. Indeed, the expression levels of some other genes (such as Leukemia Inhibitory Factor (LIF)) that were not significantly affected by 8 h anoxia exposure become upregulated in the presence of SIRT6. Therefore, SIRT6 mediates also the endothelial cellular response through the modulation of selected genes in an extreme hypoxic condition.

Convergent Genomic Signatures of High-Altitude Adaptation among Six Independently Evolved Mammals

The species living in the Qinghai-Tibet Plateau provide an excellent model system for studying the relationship between molecular convergent evolution and adaptation. Distant species experiencing the same selection pressure (i.e., hypoxia, low temperature and strong ultraviolet radiation) are likely to evolve similar genetic adaptations independently. Here, we performed comparative genomics studies on six independently evolved high-altitude species. The results also showed that the convergent evolution of the six species was mainly reflected at the level of rapidly evolving genes, and the functions of these rapidly evolving genes were mainly related to hypoxia response and DNA damage repair. In addition, we found that high-altitude species had more gene family changes than their low-altitude relatives, except for the order Lagomorpha. The results also show that the convergence of the gene family contraction of high-altitude species is much greater than that of expansion, revealing a possible pattern of species in adapting to high-altitude. Furthermore, we detected a positive selection signature in four genes related to hypoxia response and ultraviolet radiation damage in these six species (FYCO1, ERBIN, SCAMP1 and CXCL10). Our study reveals that hypoxia response might play an important role in the adaptation of independently evolved species to a high-altitude environment, providing a basic perspective for further exploring the high-altitude adaptation mechanism of different related species in the future.

Normoxic HIF-1α Stabilization Caused by Local Inflammatory Factors and Its Consequences in Human Coronary Artery Endothelial Cells

Knowledge about normoxic hypoxia-inducible factor (HIF)-1α stabilization is limited. We investigated normoxic HIF-1α stabilization and its consequences using live cell imaging, immunoblotting, Bio-Plex multiplex immunoassay, immunofluorescence staining, and barrier integrity assays. We demonstrate for the first time that IL-8 and M-CSF caused HIF-1α stabilization and translocation into the nucleus under normoxic conditions in both human coronary endothelial cells (HCAECs) and HIF-1α-mKate2-expressing HEK-293 cells. In line with the current literature, our data show significant normoxic HIF-1α stabilization caused by TNF-α, INF-γ, IL-1β, and IGF-I in both cell lines, as well. Treatment with a cocktail consisting of TNF-α, INF-γ, and IL-1β caused significantly stronger HIF-1α stabilization in comparison to single treatments. Interestingly, this cumulative effect was not observed during simultaneous treatment with IL-8, M-CSF, and IGF-I. Furthermore, we identified two different kinetics of HIF-1α stabilization under normoxic conditions. Our data demonstrate elevated protein levels of HIF-1α-related genes known to be involved in the development of atherosclerosis. Moreover, we demonstrate an endothelial barrier dysfunction in HCAECs upon our treatments and during normoxic HIF-1α stabilization comparable to that under hypoxia. This study expands the knowledge of normoxic HIF-1α stabilization and activation and its consequences on the endothelial secretome and barrier function. Our data imply an active role of HIF-1α in vivo in the vasculature in the absence of hypoxia.

Exosomal miR-27b-3p Derived from Hypoxic Cardiac Microvascular Endothelial Cells Alleviates Rat Myocardial Ischemia/Reperfusion Injury through Inhibiting Oxidative Stress-Induced Pyroptosis via Foxo1/GSDMD Signaling

Background

Exosomes derived from cardiac microvascular endothelial cells (CMECs) under hypoxia can mediate cardiac repair functions and alleviate pyroptosis and oxidative stress during ischemia-reperfusion (I/R) injury. This study is aimed at investigating the effect and mechanism of miR-27b-3p underlying hypoxic CMECs-derived exosomes against I/R injury.

Methods

CMECs were isolated from the left ventricle of Sprague-Dawley rats, followed by culturing under hypoxic conditions or pretreatment with the miR-27b-3p inhibitor. CMECs-derived exosomes were added into H9C2 cells before hypoxia/reoxygenation (H/R) or injected into the rat heart before I/R injury. An in vivo I/R injury model was established by ligating and releasing the left anterior descending coronary artery. Expression of pyroptosis-related factors was detected using Western blot, and heart infarcted size was determined by the 2,3,5-triphenyl-2H-tetrazpinolium chloride staining method. Dual-Luciferase Reporter assays were performed to analyze the interactions of nmiR-27b-3p-forkhead box O1 (Foxo1) and Gasdermin D- (GSDMD-) Foxo1. Chromatin-immunoprecipitation (ChIP) assays were performed to validate the interactions between forkhead box O1 (Foxo1) and Gasdermin D (GSDMD) and Foxo1-mediated histone acetylation of GSDMD.

Results

CMECs were successfully identified from left ventricle of Sprague-Dawley rats. The expressions of Foxo1 and pyroptosis-related proteins (GSDMD, NLPR3, cleaved caspase 1, IL-1β, and IL-18) were upregulated in the rat heart after I/R injury. Treatment of CMEC-derived exosomes, especially that under hypoxic conditions, significantly reduced pyroptosis in the rat heart. miR-27b-3p was significantly upregulated in CMEC-derived exosomes under hypoxic conditions, and miR-27b-3p inhibition in exosomes alleviated its cytoprotection and inhibited oxidative stress in H9C2 cells. Treatment with Foxo1 overexpression plasmids aggravated in vitro H/R and in vivo I/R injury by upregulating pyroptosis-related proteins. Further experiments validated that miR-27b-3p negatively targeted Foxo1, which bound to the promoter region of GSDMD.

Conclusions

These results demonstrated a great therapeutic efficacy of miR-27b-3p overexpression in hypoxic CMEC-derived exosomes in preventing the development of myocardial damage post I/R injury through inhibiting Foxo1/GSDMD signaling-induced oxidative stress and pyroptosis.

HypoxaMIRs: Key Regulators of Hallmarks of Colorectal Cancer

Hypoxia in cancer is a thoroughly studied phenomenon, and the logical cause of the reduction in oxygen tension is tumor growth itself. While sustained hypoxia leads to death by necrosis in cells, there is an exquisitely regulated mechanism that rescues hypoxic cells from their fatal fate. The accumulation in the cytoplasm of the transcription factor HIF-1α, which, under normoxic conditions, is marked for degradation by a group of oxygen-sensing proteins known as prolyl hydroxylases (PHDs) in association with the von Hippel-Lindau anti-oncogene (VHL) is critical for the cell, as it regulates different mechanisms through the genes it induces. A group of microRNAs whose expression is regulated by HIF, collectively called hypoxaMIRs, have been recognized. In this review, we deal with the hypoxaMIRs that have been shown to be expressed in colorectal cancer. Subsequently, using data mining, we analyze a panel of hypoxaMIRs expressed in both normal and tumor tissues obtained from TCGA. Finally, we assess the impact of these hypoxaMIRs on cancer hallmarks through their target genes.

TAK1 signaling is a potential therapeutic target for pathological angiogenesis

Angiogenesis plays a critical role in both physiological responses and disease pathogenesis. Excessive angiogenesis can promote neoplastic diseases and retinopathies, while inadequate angiogenesis can lead to aberrant perfusion and impaired wound healing. Transforming growth factor β activated kinase 1 (TAK1), a member of the mitogen-activated protein kinase kinase kinase family, is a key modulator involved in a range of cellular functions including the immune responses, cell survival and death. TAK1 is activated in response to various stimuli such as proinflammatory cytokines, hypoxia, and oxidative stress. Emerging evidence has recently suggested that TAK1 is intimately involved in angiogenesis and mediates pathogenic processes related to angiogenesis. Several detailed mechanisms by which TAK1 regulates pathological angiogenesis have been clarified, and potential therapeutics targeting TAK1 have emerged. In this review, we summarize recent studies of TAK1 in angiogenesis and discuss the crosstalk between TAK1 and signaling pathways involved in pathological angiogenesis. We also discuss the approaches for selectively targeting TAK1 and highlight the rationales of therapeutic strategies based on TAK1 inhibition for the treatment of pathological angiogenesis.

The Ratio of IP10 to IL-8 in Plasma Reflects and Predicts the Response of Patients With Lung Cancer to Anti-PD-1 Immunotherapy Combined With Chemotherapy

Antibodies against checkpoint inhibitors such as anti-programmed cell death protein 1 (PD-1) and its ligand anti-programmed death ligand 1 (PD-L1) have shown clinical efficacy in the treatment of multiple cancers. However, there are only a few studies on biomarkers for these targeted immunotherapies, especially in peripheral blood. We first studied the role of interferon-induced protein-10 (IP10) combined with interleukin-8 (IL-8) in peripheral blood as a biomarker of immune-combined chemotherapy for lung cancer and multiple cancers. We used the high-throughput cytokine detection platform and performed bioinformatics analysis of blood samples from 67 patients with lung cancer and 24 with multiple cancers. We selected the ratio of IP-10 to IL-8 (S2/S0, ratio of changes at 10-12 weeks after treatment to baseline) to predict the response to immunotherapy combined with chemotherapy and evaluate the survival of lung cancer patients and mixed cancer patients. In patients treated with the combination therapy, the specificity and sensitivity of IL-8 and IP10 together as predictors were improved compared with those of IL-8 and IP10 alone. Our conclusion was verified in not only lung cancer but also multiple cancer research cohorts. We then further validated the predictive effect of biomarkers in different histologic types of NSCLC and chemotherapy combined with different PD-1 drug groups. Subsequent validation should be conducted with a larger number of patients. The proposed marker IP10 (S2/S0)/IL-8 (S2/S0), as a predictive immunotherapy biomarker, has broad prospects for future clinical applications in treating patients with multiple intractable neoplasms.

Down-Regulation of microRNA-30d Alleviates Intervertebral Disc Degeneration Through the Promotion of FOXO3 and Suppression of CXCL10

MicroRNAs (miRNAs/miRs) are important biomarkers for the progression of intervertebral disc degeneration (IDD). We investigated the role of miR-30d in IDD progression through its interactions with forkhead box O3 (FOXO3) and C-X-C motif ligand 10 (CXCL10). We first measured the expression of miR-30d, FOXO3, and CXCL10 in NP cells cultured from IDD patients. RNA-immunoprecipitation (RIP), chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays were then employed to test the relationship among miR-30d, FOXO3, and CXCL10. Besides, gain- and loss-of function approaches were performed to assess the functional roles of miR-30d and FOXO3 in IDD in vitro and in vivo. We found high expression of miR-30d and CXCL10 and low expression of FOXO3 in IDD. We showed that miR-30d specifically targeted FOXO3, and that down-regulation of miR-30d promoted proliferation and inhibited apoptosis of NP cells in IDD by increasing the expression of FOXO3. Besides, FOXO3 inhibited apoptosis of NP cells by downregulation of CXCL10 expression. Moreover, inhibition of miR-30d promoted proliferation and inhibited apoptosis of NP cells in IDD by decreasing CXCL10. Furthermore, findings in the mouse IDD model confirmed the inhibitory role of decreased miR-30d in IDD progression. Thus, we show that downregulation of miR-30d could promote the proliferation of NP cells by increasing FOXO3 and decreasing CXCL10 expression, which may provide a novel therapeutic target for IDD.

Insights into the mechanism of vascular endothelial cells on bone biology

In the skeletal system, blood vessels not only function as a conduit system for transporting gases, nutrients, metabolic waste, or cells but also provide multifunctional signal molecules regulating bone development, regeneration, and remodeling. Endothelial cells (ECs) in bone tissues, unlike in other organ tissues, are in direct contact with the pericytes of blood vessels, resulting in a closer connection with peripheral connective tissues. Close-contact ECs contribute to osteogenesis and osteoclastogenesis by secreting various cytokines in the paracrine or juxtacrine pathways. An increasing number of studies have revealed that extracellular vesicles (EVs) derived from ECs can directly regulate maturation process of osteoblasts and osteoclasts. The different pathways focus on targets at different distances, forming the basis of the intimate spatial and temporal link between bone tissue and blood vessels. Here, we provide a systematic review to elaborate on the function of ECs in bone biology and its underlying mechanisms based on three aspects: paracrine, EVs, and juxtacrine. This review proposes the possibility of a therapeutic strategy targeting blood vessels, as an adjuvant treatment for bone disorders.

The Effect of Hypoxia on the Expression of CXC Chemokines and CXC Chemokine Receptors-A Review of Literature

Hypoxia is an integral component of the tumor microenvironment. Either as chronic or cycling hypoxia, it exerts a similar effect on cancer processes by activating hypoxia-inducible factor-1 (HIF-1) and nuclear factor (NF-κB), with cycling hypoxia showing a stronger proinflammatory influence. One of the systems affected by hypoxia is the CXC chemokine system. This paper reviews all available information on hypoxia-induced changes in the expression of all CXC chemokines (CXCL1, CXCL2, CXCL3, CXCL4, CXCL5, CXCL6, CXCL7, CXCL8 (IL-8), CXCL9, CXCL10, CXCL11, CXCL12 (SDF-1), CXCL13, CXCL14, CXCL15, CXCL16, CXCL17) as well as CXC chemokine receptors—CXCR1, CXCR2, CXCR3, CXCR4, CXCR5, CXCR6, CXCR7 and CXCR8. First, we present basic information on the effect of these chemoattractant cytokines on cancer processes. We then discuss the effect of hypoxia-induced changes on CXC chemokine expression on the angiogenesis, lymphangiogenesis and recruitment of various cells to the tumor niche, including myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), regulatory T cells (T_regs) and tumor-infiltrating lymphocytes (TILs). Finally, the review summarizes data on the use of drugs targeting the CXC chemokine system in cancer therapies.

The Role of NF-κB in Uterine Spiral Arteries Remodeling, Insight into the Cornerstone of Preeclampsia

Preeclampsia is one of the three leading causes of maternal morbidity and mortality worldwide. It afflicts 2-8% of pregnancies and is the most common cause of gestational hypertension. This article is focused on nuclear factor kappa B (NF-κB), its role in normal and pathological spiral arteries remodelling and development of preeclampsia, with evaluation if it is a promising therapeutic target. NF-κB is a key mediator of placentation. Since insemination, it stimulates production of proinflammatory cytokines by the uterine epithelium, which leads to activation of macrophages, uterine natural killer cells (uNKs), and other leukocytes. The trophoblast/uNK/macrophage crosstalk is crucial for implantation and spiral arteries remodeling, and NF-κB regulates that process through modification of cytokine expression, as well as cell phenotype and function. In the course of preeclampsia, the remodeling processes is disturbed by excessive inflammation and increased NF-κB activation. The pathological remodeling leads to uteroplacental dysfunction, release of proinflammatory cytokines into the maternal circulation, endothelial stress, and development of preeclampsia. The analysis of genetic and environmental inductors of NF-κB helps to distinguish preeclampsia risk groups. Furthermore, a selective inhibition of NF-κB or NF-κB activating pathways alleviates symptoms of preeclampsia in rat models; therefore, this could be an efficient therapeutic option.

Hypoperfusion is a potential inducer of immunosuppressive network in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease which causes a non-reversible cognitive impairment and dementia. The primary cause of late-onset AD remains unknown although its pathology was discovered over a century ago. Recently, the vascular hypothesis of AD has received backing from evidence emerging from neuroimaging studies which have revealed the presence of a significant hypoperfusion in the brain regions vulnerable to AD pathology. In fact, hypoxia can explain many of the pathological changes evident in AD pathology, e.g. the deposition of β-amyloid plaques and chronic low-grade inflammation. Hypoxia-inducible factor-1α (HIF-1α) stimulates inflammatory responses and modulates both innate and adaptive immunity. It is known that hypoxia-induced inflammation evokes compensatory anti-inflammatory response involving tissue-resident microglia/macrophages and infiltrated immune cells. Hypoxia/HIF-1α induce immunosuppression by (i) increasing the expression of immunosuppressive genes, (ii) stimulating adenosinergic signaling, (iii) enhancing aerobic glycolysis, i.e. lactate production, and (iv) augmenting the secretion of immunosuppressive exosomes. Interestingly, it seems that these common mechanisms are also involved in the pathogenesis of AD. In AD pathology, an enhanced immunosuppression appears, e.g. as a shift in microglia/macrophage phenotypes towards the anti-inflammatory M2 phenotype and an increase in the numbers of regulatory T cells (Treg). The augmented anti-inflammatory capacity promotes the resolution of acute inflammation but persistent inflammation has crucial effects not only on immune cells but also harmful responses to the homeostasis of AD brain. I will examine in detail the mechanisms of the hypoperfusion/hypoxia-induced immunosuppressive state in general and especially, in its association with AD pathogenesis. These immunological observations support the vascular hypothesis of AD pathology.

Downregulation of the CCL2/CCR2 and CXCL10/CXCR3 axes contributes to antitumor effects in a mouse model of malignant glioma

Glioblastoma multiforme involves glioma stem cells (GSCs) that are resistant to various therapeutic approaches. Here, we studied the importance of paracrine signaling in the glioma microenvironment by focusing on the celecoxib-mediated role of chemokines C–C motif ligand 2 (CCL2), C-X-C ligand 10 (CXCL10), and their receptors, CCR2 and CXCR3, in GSCs and a GSC-bearing malignant glioma model. C57BL/6 mice were injected with orthotopic GSCs intracranially and divided into groups administered either 10 or 30 mg/kg celecoxib, or saline to examine the antitumor effects associated with chemokine expression. In GSCs, we analyzed cell viability and expression of chemokines and their receptors in the presence/absence of celecoxib. In the malignant glioma model, celecoxib exhibited antitumor effects in a dose dependent manner and decreased protein and mRNA levels of Ccl2 and CxcL10 and Cxcr3 but not of Ccr2. CCL2 and CXCL10 co-localized with Nestin⁺ stem cells, CD16⁺ or CD163⁺ macrophages and Iba-1⁺ microglia. In GSCs, celecoxib inhibited Ccl2 and Cxcr3 expression in a nuclear factor-kappa B-dependent manner but not Ccr2 and CxcL10. Moreover, Ccl2 silencing resulted in decreased GSC viability. These results suggest that celecoxib-mediated regulation of the CCL2/CCR2 and CXCL10/ CXCR3 axes may partially contribute to glioma-specific antitumor effects.

Modeling of the immune response in the pathogenesis of solid tumors and its prognostic significance

BACKGROUND

Tumor initiation and subsequent progression are usually long-term processes, spread over time and conditioned by diverse aspects. Many cancers develop on the basis of chronic inflammation; however, despite dozens of years of research, little is known about the factors triggering neoplastic transformation under these conditions. Molecular characterization of both pathogenetic states, i.e., similarities and differences between chronic inflammation and cancer, is also poorly defined. The secretory activity of tumor cells may change the immunophenotype of immune cells and modify the extracellular microenvironment, which allows the bypass of host defense mechanisms and seems to have diagnostic and prognostic value. The phenomenon of immunosuppression is also present during chronic inflammation, and the development of cancer, due to its duration, predisposes patients to the promotion of chronic inflammation. The aim of our work was to discuss the above issues based on the latest scientific insights. A theoretical mechanism of cancer immunosuppression is also proposed.

CONCLUSIONS

Development of solid tumors may occur both during acute and chronic phases of inflammation. Differences in the regulation of immune responses between precancerous states and the cancers resulting from them emphasize the importance of immunosuppressive factors in oncogenesis. Cancer cells may, through their secretory activity and extracellular transport mechanisms, enhance deterioration of the immune system which, in turn, may have prognostic implications.

MxA suppresses TAK1-IKKα/β-NF-κB mediated inflammatory cytokine production to facilitate Mycobacterium tuberculosis infection

OBJECTIVES

Interferons (IFNs) play multifunctional roles in host defense against infectious diseases by inducing IFN-stimulated genes (ISGs). However, little is known about how ISGs regulate host immune response to Mycobacterium tuberculosis (Mtb) infection, the major cause of tuberculosis (TB).

METHODS

We thus profiled the potential effects and mechanisms of eight Mtb-induced ISGs on Mtb infection by RNA interference in human macrophages (Mφs) derived from peripheral blood monocytes (hMDMs) and THP-1 cell line derived Mφs (THP-1-Mφs).

RESULTS

MxA silencing significantly decreased intracellular Mtb infection in Mφs. Mechanistically, MxA silencing promoted inflammatory cytokines IL-1β, IL-6 and TNF-α production, and induced NF-κB p65 activation. Pharmacological inhibition of NF-κB p65 activation or gene silencing of NF-κB p65 blocked the increased production of IL-1β, IL-6 and TNF-α and restored Mtb infection by MxA silencing. Furthermore, pharmacological inhibition of TAK1 and IKKα/β blocked NF-κB p65 activation and subsequent production of pro-inflammatory cytokines by MxA silencing. Isoniazid (INH) treatment and MxA silencing could promote TAK1-IKKα/β-NF-κB signaling pathway activation and combat Mtb infection independently.

CONCLUSIONS

Our results reveal a novel role of MxA in regulating TAK1-IKKα/β-NF-κB signaling activation and production of antimicrobial inflammatory cytokines upon Mtb infection, providing a potential target for clinical treatment of TB.

CXCL-10: a new candidate for melanoma therapy?

BACKGROUND

Melanoma is a malignancy that stems from melanocytes and is defined as the most dangerous skin malignancy in terms of metastasis and mortality rates. CXC motif chemokine 10 (CXCL10), also known as interferon gamma-induced protein-10 (IP-10), is a small cytokine-like protein secreted by a wide variety of cell types. CXCL10 is a ligand of the CXC chemokine receptor-3 (CXCR3) and is predominantly expressed by T helper cells (Th cells), cytotoxic T lymphocytes (CTLs), dendritic cells, macrophages, natural killer cells (NKs), as well as some epithelial and cancer cells. Similar to other chemokines, CXCL10 plays a role in immunomodulation, inflammation, hematopoiesis, chemotaxis and leukocyte trafficking.

CONCLUSIONS

Recent studies indicate that the CXCL10/CXCR3 axis may act as a double-edged sword in terms of pro- and anti-cancer activities in a variety of tissues and cells, especially in melanoma cells and their microenvironments. Most of these activities arise from the CXCR3 splice variants CXCR3-A, CXCR3-B and CXCR3-Alt. In this review, we discuss the pro- and anti-cancer properties of CXCL10 in various types of tissues and cells, particularly melanoma cells, including its potential as a therapeutic target.

Acute Kidney Injury in Children after Hematopoietic Cell Transplantation Is Associated with Elevated Urine CXCL10 and CXCL9

Acute kidney injury (AKI) is nearly universally associated with worse outcomes, especially among children after hematopoietic stem cell transplant (HCT). Our objective was to examine urinary immune biomarkers of AKI after HCT to provide insights into novel mechanisms of kidney injury in this population. Studying patients undergoing allogeneic HCT provides a unique opportunity to examine immune markers of AKI because the risk of AKI is high and the immune system newly develops after transplant. Children (>2 years old) and young adults undergoing their first allogeneic HCT and enrolled in a prospective, observational cohort study at 2 large children's hospitals had urine collected pre-HCT and monthly for the first 4 months after HCT. Urine samples at each monthly time point were assayed for 8 immune-related biomarkers. AKI was defined as a 1.5-fold increase in the monthly serum creatinine value, which was recorded ±1 day from when the research urine sample was obtained, as compared with the pre-HCT baseline. Generalized estimating equation regression analysis evaluated the association between the monthly repeated measures (urinary biomarkers and AKI). A total of 176 patients were included from 2 pediatric centers. Thirty-six patients from 1 center were analyzed as a discovery cohort and the remaining 140 patients from the second center were analyzed as a validation cohort. AKI rates were 18% to 35% depending on the monthly time point after HCT. Urine CXCL10 and CXCL9 concentrations were significantly higher among children who developed AKI compared with children who did not (P < .01) in both cohorts. In order to gain a better understanding of the cellular source for these biomarkers in the urine, we also analyzed in vitro expression of CXCL10 and CXCL9 in kidney cell lines after stimulation with interferon-γ and interferon-α. HEK293-epithelial kidney cells demonstrated interferon-induced expression of CXCL10 and CXCL9, suggesting a potential mechanism driving the key finding. CXCL10 and CXCL9 are associated with AKI after HCT and are therefore promising biomarkers to guide improved diagnostic and treatment strategies for AKI in this high-risk population.

Blocking ATM-dependent NF-κB pathway overcomes niche protection and improves chemotherapy response in acute lymphoblastic leukemia

Bone marrow (BM) niche responds to chemotherapy-induced cytokines secreted from acute lymphoblastic leukemia (ALL) cells and protects the residual cells from chemotherapeutics in vivo. However, the underlying molecular mechanisms for the induction of cytokines by chemotherapy remain unknown. Here, we found that chemotherapeutic drugs (e.g., Ara-C, DNR, 6-MP) induced the expression of niche-protecting cytokines (GDF15, CCL3 and CCL4) in both ALL cell lines and primary cells in vitro. The ATM and NF-κB pathways were activated after chemotherapy treatment, and the pharmacological or genetic inhibition of these pathways significantly reversed the cytokine upregulation. Besides, chemotherapy-induced NF-κB activation was dependent on ATM-TRAF6 signaling, and NF-κB transcription factor p65 directly regulated the cytokines expression. Furthermore, we found that both pharmacological and genetic perturbation of ATM and p65 significantly decreased the residual ALL cells after Ara-C treatment in ALL xenograft mouse models. Together, these results demonstrated that ATM-dependent NF-κB activation mediated the cytokines induction by chemotherapy and ALL resistance to chemotherapeutics. Inhibition of ATM-dependent NF-κB pathway can sensitize ALL to chemotherapeutics, providing a new strategy to eradicate residual chemo-resistant ALL cells.

RP105 ameliorates hypoxia̸reoxygenation injury in cardiac microvascular endothelial cells by suppressing TLR4̸MAPKs̸NF-κB signaling

The radioprotective 105 kDa protein (RP105) has been implicated in the pathological process of multiple cardiovascular diseases through its functional and physical interactions with Toll‑like receptor 4 (TLR4). However, the effects of RP105 on cardiac microvascular endothelial cells (CMECs) in response to hypoxia̸reoxygenation (H̸R) injury have not been extensively investigated. The aim of the present study was to elucidate the potential roles of RP105 in the protection of CMECs against H̸R injury, and investigate the underlying mechanisms. CMECs isolated from Sprague‑Dawley rats were transduced with adenoviral vectors encoding RP105 or green fluorescent protein (GFP). At 48 h post‑transfection, CMECs were subjected to hypoxia for 4 h and reoxygenation for 2 h (H̸R) to simulate the in vivo ischemia̸reperfusion model. The mRNA and protein levels of RP105 were detected by reverse transcription‑quantitative polymerase chain reaction and western blot analysis, respectively. The effects of RP105 on CMEC proliferation, migration and apoptosis were measured by GFP‑8, Transwell chamber and flow cytometry assays, respectively. The secretion of interleukin (IL)‑6 and tumor necrosis factor (TNF)‑α in the culture medium was measured by ELISA. Moreover, the expression level of TLR4, p38 mitogen‑activated protein kinase (MAPK), extracellular-signal-regulated kinase 1̸2, c-Jun N-terminal kinase, nuclear factor (NF)‑κB̸p65, IL‑6, TNF‑α and intercellular adhesion melecule‑1 was evaluated by western blot analysis. The results demonstrated that RP105 was minimally expressed in CMECs subjected to H̸R injury. Overexpression of RP105 via adenoviral vectors was able to significantly protect CMECs against H̸R injury, as evidenced by the promotion of cell proliferation and migration, as well as the amelioration of inflammation and apoptosis. These beneficial effects were at least partly mediated through inhibition of TLR4̸MAPKs̸NF‑κB signaling. Therefore, RP105 may be a promising candidate for prevention against CMECs‑associated H̸R injury.

Qiliqiangxin attenuates hypoxia-induced injury in primary rat cardiac microvascular endothelial cells via promoting HIF-1α-dependent glycolysis

Protection of cardiac microvascular endothelial cells (CMECs) against hypoxia injury is an important therapeutic strategy for treating ischaemic cardiovascular disease. In this study, we investigated the effects of qiliqiangxin (QL) on primary rat CMECs exposed to hypoxia and the underlying mechanisms. Rat CMECs were successfully isolated and passaged to the second generation. CMECs that were pre-treated with QL (0.5 mg/mL) and/or HIF-1α siRNA were cultured in a three-gas hypoxic incubator chamber (5% CO₂ , 1% O₂ , 94% N₂ ) for 12 hours. Firstly, we demonstrated that compared with hypoxia group, QL effectively promoted the proliferation while attenuated the apoptosis, improved mitochondrial function and reduced ROS generation in hypoxic CMECs in a HIF-1α-dependent manner. Meanwhile, QL also promoted angiogenesis of CMECs via HIF-1α/VEGF signalling pathway. Moreover, QL improved glucose utilization and metabolism and increased ATP production by up-regulating HIF-1α and a series of glycolysis-relevant enzymes, including glucose transport 1 (GLUT1), hexokinase 2 (HK2), 6-phosphofructokinase 1 (PFK1), pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA). Our findings indicate that QL can protect CMECs against hypoxia injury via promoting glycolysis in a HIF-1α-dependent manner. Lastly, the results suggested that QL-dependent enhancement of HIF-1α protein expression in hypoxic CMECs was associated with the regulation of AMPK/mTOR/HIF-1α pathway, and we speculated that QL also improved HIF-1α stabilization through down-regulating prolyl hydroxylases 3 (PHD3) expression.

Inhibition of C-X-C motif chemokine 10 reduces graft loss mediated by memory CD8+ T cells in a rat cardiac re-transplant model

The interaction of chemokine (C-X-C motif) ligand 10 (CXCL10) with its receptor (CXCR3) is a critical process in recruiting donor reactive T cells to a graft and alloantigen-specific memory T (Tm) cells exert a principal function in promoting graft dysfunction during accelerated cardiac rejection. However, whether CXCL10 chemokine exerts any effects on acute accelerated rejection mediated by CD8⁺ Tm cells in a re-transplant model has remained elusive. The present study established a cardiac transplant model by advanced microsurgery technology and improved organ storage. A novel rat model of cardiac re-transplantation was established at 40 days following primary heart transplant. The experiment included two parts, and when models were established, the rats were divided into two groups: Primary cardiac transplant (HTx) and re-transplantation without treatment (HRTx). In part 1, recipients from part 2, including re-transplantation without treatment (HRTx+NS) and re-transplantation treated with anti-CXCL10 antibodies (500 µg every other day by intraperitoneal injection; HRTx+CXCL10 Abs group). The graft survival time was observed and graft infiltration by inflammatory cells was assessed via histology of cardiac graft sections; in addition, the gene expression and the serum concentration of CXCL10 in each group was assessed. Indexes such as rejection-associated cytokines were assayed by reverse-transcription quantitative PCR and ELISA kits, and flow cytometry of splenocytes was used to detect Tm cells in the re-transplantation groups. The results demonstrated that level of CXCL10 was significantly increased and the graft mean survival time was shortened accompanied with aggravated lymphocyte cell infiltration in the HRTx group when compared that in the HTx group; in addition, the serum levels and mRNA expression of interleukin (IL)-2 and interferon (IFN)-γ were increased, while transforming growth factor (TGF)-β was decreased in the HRTx group. Furthermore, neutralization of CXCL10 prolonged the graft mean survival time and delayed accelerated rejection. Compared with that in the HRTx+NS group, serum levels and graft tissue mRNA expression of IFN-γ and IL-2 were decreased in the HRTx+CXCL10 Abs group, while TGF-β mRNA was significantly increased but the serum concentration was not significantly affected. In addition, there was no difference in IL-10 between the two groups, while delayed accelerated rejection paralleled with inflammatory cell infiltration decreased and the proliferation and differentiation of CD8⁺ Tm cells in secondary lymphoid organs were reduced in the HRTx+CXCL10 Abs group vs. those in the HRTx+NS group. The present study demonstrated that CXCL10 had a crucial role in cardiac transplantation and re-transplantation, and that treatment with CXCL10 antibodies delays accelerated acute rejection mediated by Tm cells in a rat model of cardiac re-transplantation.

CXCL9, CXCL10, CXCL11/CXCR3 axis for immune activation - A target for novel cancer therapy

Chemokines are proteins which induce chemotaxis, promote differentiation of immune cells, and cause tissue extravasation. Given these properties, their role in anti-tumor immune response in the cancer environment is of great interest. Although immunotherapy has shown clinical benefit for some cancer patients, other patients do not respond. One of the mechanisms of resistance to checkpoint inhibitors may be chemokine signaling. The CXCL9, -10, -11/CXCR3 axis regulates immune cell migration, differentiation, and activation, leading to tumor suppression (paracrine axis). However, there are some reports that show involvements of this axis in tumor growth and metastasis (autocrine axis). Thus, a better understanding of CXCL9, -10, -11/CXCR3 axis is necessary to develop effective cancer control. In this article, we summarize recent evidence regarding CXCL9, CXCL10, CXCL11/CXCR3 axis in the immune system and discuss their potential role in cancer treatment.

Analysis of region specific gene expression patterns in the heart and systemic responses after experimental myocardial ischemia

Aims

Ischemic myocardial injury leads to the activation of inflammatory mechanisms and results in ventricular remodeling. Although great efforts have been made to unravel the molecular and cellular processes taking place in the ischemic myocardium, little is known about the effects on the surrounding tissue and other organs. The aim of this study was to determine region specific differences in the myocardium and in distant organs after experimental myocardial infarction by using a bioinformatics approach.

Methods and Results

A porcine closed chest reperfused acute myocardial infarction model and mRNA microarrays have been used to evaluate gene expression changes. Myocardial infarction changed the expression of 8903 genes in myocardial-, 856 in hepatic- and 338 in splenic tissue. Identification of myocardial region specific differences as well as expression profiling of distant organs revealed clear gene-regulation patterns within the first 24 hours after ischemia. Transcription factor binding site analysis suggested a strong role for Kruppel like factor 4 (Klf4) in the regulation of gene expression following myocardial infarction, and was therefore investigated further by immunohistochemistry. Strong nuclear Klf4 expression with clear region specific differences was detectable in porcine and human heart samples after myocardial infarction.

Conclusion

Apart from presenting a post myocardial infarction gene expression database and specific response pathways, the key message of this work is that myocardial ischemia does not end at the injured myocardium. The present results have enlarged the spectrum of organs affected, and suggest that a variety of organ systems are involved in the co-ordination of the organism´s response to myocardial infarction.

Intense light-elicited upregulation of miR-21 facilitates glycolysis and cardioprotection through Per2-dependent mechanisms

A wide search for ischemic preconditioning (IPC) mechanisms of cardioprotection identified the light elicited circadian rhythm protein Period 2 (Per2) to be cardioprotective. Studies on cardiac metabolism found a key role for light elicited Per2 in mediating metabolic dependence on carbohydrate metabolism. To profile Per2 mediated pathways following IPC of the mouse heart, we performed a genome array and identified 352 abundantly expressed and well-characterized Per2 dependent micro RNAs. One prominent result of our in silico analysis for cardiac Per2 dependent micro RNAs revealed a selective role for miR-21 in the regulation of hypoxia and metabolic pathways. Based on this Per2 dependency, we subsequently found a diurnal expression pattern for miR-21 with higher miR-21 expression levels at Zeitgeber time (ZT) 15 compared to ZT3. Gain or loss of function studies for miR-21 using miRNA mimics or miRNA inhibitors and a Seahorse Bioanalyzer uncovered a critical role of miR-21 for cellular glycolysis, glycolytic capacity, and glycolytic reserve. Exposing mice to intense light, a strategy to induce Per2, led to a robust induction of cardiac miR-21 tissue levels and decreased infarct sizes, which was abolished in miR-21-/- mice. Similarly, first translational studies in humans using intense blue light exposure for 5 days in healthy volunteers resulted in increased plasma miR-21 levels which was associated with increased phosphofructokinase activity, the rate-limiting enzyme in glycolysis. Together, we identified miR-21 as cardioprotective downstream target of Per2 and suggest intense light therapy as a potential strategy to enhance miR-21 activity and subsequent carbohydrate metabolism in humans.

The CXCL10/CXCR3 Axis and Cardiac Inflammation: Implications for Immunotherapy to Treat Infectious and Noninfectious Diseases of the Heart

Accumulating evidence reveals involvement of T lymphocytes and adaptive immunity in the chronic inflammation associated with infectious and noninfectious diseases of the heart, including coronary artery disease, Kawasaki disease, myocarditis, dilated cardiomyopathies, Chagas, hypertensive left ventricular (LV) hypertrophy, and nonischemic heart failure. Chemokine CXCL10 is elevated in cardiovascular diseases, along with increased cardiac infiltration of proinflammatory Th1 and cytotoxic T cells. CXCL10 is a chemoattractant for these T cells and polarizing factor for the proinflammatory phenotype. Thus, targeting the CXCL10 receptor CXCR3 is a promising therapeutic approach to treating cardiac inflammation. Due to biased signaling CXCR3 also couples to anti-inflammatory signaling and immunosuppressive regulatory T cell formation when activated by CXCL11. Numbers and functionality of regulatory T cells are reduced in patients with cardiac inflammation, supporting the utility of biased agonists or biologicals to simultaneously block the pro-inflammatory and activate the anti-inflammatory actions of CXCR3. Other immunotherapy strategies to boost regulatory T cell actions include intravenous immunoglobulin (IVIG) therapy, adoptive transfer, immunoadsorption, and low-dose interleukin-2/interleukin-2 antibody complexes. Pharmacological approaches include sphingosine 1-phosphate receptor 1 agonists and vitamin D supplementation. A combined strategy of switching CXCR3 signaling from pro- to anti-inflammatory and improving Treg functionality is predicted to synergistically lessen adverse cardiac remodeling.