CD69 expression on Treg cells prevents chronic heart damage after myocardial infarction

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministerio de Ciencia e Innovación (MCIN), through the Carlos III Institute of Health (ISCIII)-Fondo de Investigación Sanitaria (PI19/00545)

Background

Increasing evidences advocate for an important function of T cells in controlling immune homeostasis and pathogenesis after myocardial infarction (MI), although the molecular mechanisms remain elusive.

Result and Methods

In this study, a broad analysis of immune markers in 283 patients show a significant CD69 overexpression on Treg cells after MI. Our results in mice demonstrate that CD69 expression on Treg cells increases survival after left-anterior-descending coronary artery (LAD)-ligation. Cd69-/- mice develop strong IL17A+ gdT cell responses after ischemia that increase myocardial inflammation and, consequently, worsen cardiac function. CD69+ Treg cells induce apoptosis and decrease IL-17A production in gdT cells by a CD39-dependent mechanism. Adoptive transfer of CD69+ Treg cells to Cd69-/- mice after LAD-ligation reduces IL17A+ gdT cell recruitment increasing survival. Consistently, clinical data from two independent cohorts of patients indicate that increased CD69 expression in peripheral blood cells after acute MI is associated with a lower risk of re-hospitalization for chronic heart failure (CHF) after 2.5 years of follow-up. This result remained significant after adjustment for age, sex and traditional cardiac damage biomarkers (OR 0.929, 95% CI, 0.838-0.980; p<0.0409).

Conclusion

Our data highlight CD69 expression on T cells as a therapeutic and prognostic target to prevent CHF after MI.

CD69 expression in regulatory T cells protects from the immune-mediated damage after myocardial infarction

 

CD69 depletion from the lymphoid compartment promotes a Th17/Treg imbalance and exacerbates the development of atherosclerosis. As atherosclerosis is the trigger of myocardial infarction, we have analyzed the role of CD69 in Treg cells after a) permanent occlusion of the left-anterior-descending coronary artery (LAD-ligation) in mice, and b) coronary angiography in two cohorts of acute myocardial infarction (MI) patients.

Our data show that CD69 expression in Treg cells is critical to maintain immune homeostasis after myocardial infarction and increases overall survival in mice after LAD-ligation. Cd69−/− mice develop IL17A+ gdT cell responses early after ischemia that increment myocardial inflammation and, consequently, worsen cardiac function. Furthermore, we found that CD69+ Treg cells induce apoptosis and diminish IL-17A production in gdT cells by a mechanism dependent on membrane CD39 ectonucleotidase activity. The adoptive transfer of CD69+ Treg cells to Cd69−/− mice after LAD-ligation reduces IL17A+ gdT cell recruitment, resulting in increased survival and improved outcome.

In accordance, data from two independent cohorts of patients indicate that increased levels of CD69+ Treg cells in the blood of patients early after MI is associated with lower risk of developing chronic heart failure. Our data support the role of CD69+ Treg cells to prevent excess of inflammation and damage after MI, whose value remains associated with improved heart function in the medium term.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Fondo de Investigaciones Sanitarias. Instituto de Salud Carlos III. Ministerio de Ciencia Innovaciόn y Universidades (Spanish Government). Summary immage

Evaluating Invasive EEG Implantations with Structural Imaging Data and Functional Scalp EEG Recordings from Epilepsy Patients

Seizures in patients with medically refractory epilepsy (MRE) cannot be controlled with drugs. For focal MRE, seizures originate in the epileptogenic zone (EZ), which is the minimum amount of cortex that must be treated to be seizure free. Localizing the EZ is often a laborious process wherein clinicians first inspect scalp EEG recordings during several seizure events, and then formulate an implantation plan for subsequent invasive monitoring. The goal of implantation is to place electrodes into the brain region covering the EZ. Then, during invasive monitoring, clinicians visually inspect intracranial EEG recordings to more precisely localize the EZ. Finally, the EZ is then surgically ablated, removed or treated with electrical stimulation. Unfortunately success rates average at 50%. Such grim outcomes call for analytical assistance in creating more accurate implantation plans from scalp EEG. In this paper, we introduce a method that combines imaging data (CT and MRI scans) with scalp EEG to derive an implantation distribution. Specifically, scalp EEG data recorded over a seizure event is converted into a time-gamma frequency map, which is then processed to derive a spectrally annotated implantation distribution (SAID). The SAID represents a distribution of gamma power in each of eight cortical lobe/hemisphere partitions. We applied this method to 4 MRE patients who underwent treatment, and found that the SAID distribution overlapped more with clinical implantations in success cases than in failed cases. These preliminary findings suggest that the SAID may help in improving EZ localization accuracy and surgical outcomes.

Virtual Cortical Stimulation Mapping of Epilepsy Networks to Localize the Epileptogenic Zone

Cortical stimulation mapping (CSM) is a common clinical procedure for mapping eloquent cortex in epilepsy patients. Electrical responses to the stimulation, or after-discharges (ADs), that occur in response to stimulation can point to unstable regions of cortex that are more prone to spontaneous seizures. Clinicians are interested in identifying regions that start seizures, i.e., the epileptogenic zone (EZ), so that they can target treatment. However, during CSM, not all regions are stimulated, as it would be time-consuming and potentially harmful to the patient. This limits the clinician's ability to fully explore ADs to reliably localize the EZ. In this paper, we develop a virtual CSM procedure that processes pre-seizure intracranial EEG recordings obtained from epilepsy patients being treated at three different epilepsy centers. First, we identify a linear time varying network (LTVN) model from electrocorticography (ECoG) and stereo-EEG (SEEG) data using sparse least squares estimation for each patient. We then construct an virtual CSM by applying impulse perturbations to each electrode contact in the LTVN model and then measuring the ADs of the network. We summarize the l2-norm of the responses in the form of a heatmap that shows the spatio-temporal evolution of the ADs before, during, and after seizures. Finally we compute an impulse response ratio (IRR) metric from each heatmap, that measures the ratio between the mean norm of ADs of clinically annotated EZ contacts and the mean norm of ADs of the remaining contacts. We find that the IRR is higher in maps derived from patients with successful surgical outcomes and lower in failed surgical outcomes. This suggests that virtual CSM may provide valuable information to clinicians regarding EZ location.

Linear time-varying model characterizes invasive EEG signals generated from complex epileptic networks

Electrocorticography (ECoG) and stereotactic electroencephalography (SEEG) are popular tools for studying neural mechanisms governing behavior and neural disorders, such as epilepsy. In particular, clinicians are interested in identifying brain regions that start seizures, i.e., the epileptogenic zone (EZ) from such invasive recordings. Currently, they visually inspect signals from each electrode to locate abnormal activity, and are not informed by predictive models that can characterize such recordings and potentially increase accuracy in localizing the EZ. In this paper, we test whether a simple linear time varying (LTV) model is sufficient to characterize both ECoG and SEEG activity. Specifically, we construct linear time invariant models in consecutive time windows before, during and after seizure events creating an LTV model from data collected in one ECoG and one SEEG patient. We find that these LTV models accurately reconstruct both ECoG and SEEG time series measured suggesting that these LTV models can be used for EZ localization.

Synthesis and structures of photoactive rhenium carbonyl complexes derived from 2-(pyridin-2-yl)-1,3-benzothiazole, 2-(quinolin-2-yl)-1,3-benzothiazole and 1,10-phenanthroline

Carbon monoxide (CO) has recently been identified as a gaseous signaling molecule that exerts various salutary effects in mammalian pathophysiology. Photoactive metal carbonyl complexes (photoCORMs) are ideal exogenous candidates for more controllable and site-specific CO delivery compared to gaseous CO. Along this line, our group has been engaged for the past few years in developing group-7-based photoCORMs towards the efficient eradication of various malignant cells. Moreover, several such complexes can be tracked within cancerous cells by virtue of their luminescence. The inherent luminecscent nature of some photoCORMs and the change in emission wavelength upon CO release also provide a covenient means to track the entry of the prodrug and, in some cases, both the entry and CO release from the prodrug. In continuation of the research circumscribing the development of trackable photoCORMs and also to graft such molecules covalently to conventional delivery vehicles, we report herein the synthesis and structures of three rhenium carbonyl complexes, namely, fac-tricarbonyl[2-(pyridin-2-yl)-1,3-benzothiazole-κ²N,N'](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C₇H₇N)(C₁₂H₈N₂S)(CO)₃](CF₃SO₃), (1), fac-tricarbonyl[2-(quinolin-2-yl)-1,3-benzothiazole-κ²N,N'](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C₇H₇N)(C₁₆H₁₀N₂S)(CO)₃](CF₃SO₃), (2), and fac-tricarbonyl[1,10-phenanthroline-κ²N,N'](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C₇H₇N)(C₁₂H₈N₂)(CO)₃](CF₃SO₃), (3). In all three complexes, the Re^I center resides in a distorted octahedral coordination environment. These complexes exhibit CO release upon exposure to low-power UV light. The apparent CO release rates of the complexes have been measured to assess their comparative CO-donating capacity. The three complexes are highly luminescent and this in turn provides a convenient way to track the entry of the prodrug molecules within biological targets.

Differential Gene Expression Profiles Reflecting Macrophage Polarization in Aging and Periodontitis Gingival Tissues

Recent evidence has determined a phenotypic and functional heterogeneity for macrophage populations. This plasticity of macrophage function has been related to specific properties of subsets (M1 and M2) of these cells in inflammation, adaptive immune responses and resolution of tissue destructive processes. This investigation hypothesized that targeted alterations in the distribution of macrophage phenotypes in aged individuals, and with periodontitis would be skewed towards M1 inflammatory macrophages in gingival tissues. The study used a non-human primate model to evaluate gene expression profiles as footprints of macrophage variation in healthy and periodontitis gingival tissues from animals 3-23 years of age and in periodontitis tissues in adult and aged animals. Significant increases in multiple genes reflecting overall increases in macrophage activities were observed in healthy aged tissues, and were significantly increased in periodontitis tissues from both adults and aged animals. Generally, gene expression patterns for M2 macrophages were similar in healthy young, adolescent and adult tissues. However, modest increases were noted in healthy aged tissues, similar to those seen in periodontitis tissues from both age groups. M1 macrophage gene transcription patterns increased significantly over the age range in healthy tissues, with multiple genes (e.g. CCL13, CCL19, CCR7 and TLR4) significantly increased in aged animals. Additionally, gene expression patterns for M1 macrophages were significantly increased in adult health versus periodontitis and aged healthy versus periodontitis. The findings supported a significant increase in macrophages with aging and in periodontitis. The primary increases in both healthy aged tissues and, particularly periodontitis tissues appeared in the M1 phenotype.

Expression and functional relevance of UGT1A4 in a cohort of human drug-resistant epileptic brains

PURPOSE

Brain drug bioavailability is regulated by the blood-brain barrier (BBB). It was recently suggested that cytochrome P450 (CYP) enzymes could act in concert with multidrug transporter proteins to regulate drug penetration and distribution into the diseased brain. The possibility that phase II metabolic enzymes could be expressed in the epileptic brain has been not evaluated. Phase II enzymes are involved in the metabolism of common antiepileptic drugs (AEDs).

METHODS

Phase II enzyme UGT1A4 brain expression was evaluated in temporal lobe resections from patients with epilepsy. UGT1A4 expression was determined by western blot and immunocytochemistry in primary cultures of human drug-resistant brain endothelial human brain epileptic endothelial cells (EPI-EC)s and commercially available control cells human brain microvascular endothelial cells (HBMECs). Lack of DNA condensation measured by 4',6-diamidino-2-phenylindole (DAPI) was used as a surrogate marker of cell viability and was correlated to UGT1A4 expression high performance liquid chromatography ultraviolet detection (HPLC-UV) was used to quantify lamotrigine metabolism by EPI-EC and HBMEC. The appearance of the specific lamotrigine metabolite, 2-n glucuronide (MET-1), was also evaluated. Lamotrigine and MET-1 levels were measured in selected surgical brain and matched blood samples.

KEY FINDINGS

UGT1A4 expression was observed in BBB endothelial cells and neurons. Our quantification study revealed variable levels of UGT1A4 expression across the brain specimens analyzed. Neurons devoid of UGT1A4 expression displayed nuclear DAPI condensation, a sign of cellular distress. UGT1A4 overexpression in EPI-EC, as compared to HBMEC, was reflected by a proportional increase in lamotrigine metabolism. The lamotrigine metabolite, MET-1, was formed in vitro by EPI-EC and, to a lesser extent, by HBMEC. HPLC-UV measurements of brain and blood samples obtained from patients receiving lamotrigine prior to surgery revealed the presence of lamotrigine and its metabolites in the brain.

SIGNIFICANCE

These initial results suggest the presence of a phase II enzyme in the epileptic brain. Further studies are required to fully describe the pattern of brain UGT1A4 expression in relation to clinical variables and drug resistance.

Effect of eplerenone on hypertension-associated renal damage in rats: potential role of peroxisome proliferator activated receptor gamma (PPAR-γ)

Several factors, including mineralocorticoids, have been implicated in the renal damage associated with hypertension. Peroxisome proliferator activated receptor gamma (PPAR-γ) agonists improve renal damage associated with different pathologies. Therefore, our hypothesis was that mineralocorticoid receptor blockade ameliorates renal damage associated with hypertension and that this improvement may be mediated by PPAR-γ. Spontaneously hypertensive rats (SHR) were treated with either vehicle or eplerenone, a mineralocorticoid receptor antagonist, at two different doses: 30 and 100 mg/kg/day for 10 weeks. Age-matched Wistar Kyoto rats (WKY) were used as a normotensive reference group. SHR showed tubulointersticial fibrosis and mild tubular atrophy. These alterations were accompanied by increases in renal cortex gene expression of transforming growth factor beta (TGF-β) connective tissue growth factor (CTGF) and phosphorylated Smad2 protein levels, factors involved in the fibrotic response. Interleukin 1-beta (IL-1β) and tumor necrosis factor alpha (TNF-α) gene expression were also increased. By contrast, lysyl oxidase (LOX) expression and PPAR-γ protein levels were decreased in SHR as compared with normotensive animals. Only the high dose of eplerenone was able to reduce blood pressure and partially prevent LOX down-regulation in SHR. Both eplerenone doses significantly ameliorated interstitial fibrosis and tubular atrophy, reduced TGF-β, CTGF and cytokine gene expression, and decreased Smad2 activation, while normalizing PPAR-γ protein levels.

CONCLUSIONS

Mineralocorticoid receptor activation participates in hypertension-associated renal damage. This effect seems to involve stimulation of both fibrotic and inflammatory processes mediated (at least in part) by a down-regulation of PPAR-γ that can favour an up-regulation of the TGF-β/Smad signalling pathway.

Characterization of a cDNA encoding a cytosolic peptidylprolyl cis-trans-isomerase from Blattella germanica

Cyclophilins are an abundant and ubiquitous class of proteins first identified by their high affinity for the immunosuppressive drug cyclosporin A. Cyclophilins have peptidylprolyl cis/trans-isomerase activity in vitro, and thus may be involved in protein folding and trafficking in vivo. In this study, we report the cloning and characterization of a Blattella germanica cyclophilin cDNA. Analysis of this 846-bp cDNA reveals an open reading frame coding for a polypeptide of 164 amino acid residues with a molecular mass of 17934 Da. This B. germanica cyclophilin shares a central peptidylprolyl cis/trans-isomerase and a cyclosporin-A-binding domain with other cyclophilin sequences. The B. germanica cyclophilin amino acid sequence shares 83% identity with the cytosolic cyclophilin isoform from Drosophila melanogaster (Cyp-1). This identity suggests that B. germanica cyclophilin is a member of the cytosolic cyclophilin A (CyPA) family. From the alignment of cyclophilin sequences, we have found that 62 residues (positional identity of 40%) have remained invariant in eukaryotes for more than 1 billion years of divergence. We calculated a unit evolutionary period of 30.9 million years for the cytosolic isoform. Northern-blot analyses show that B. germanica CyPA mRNA is abundant, and present in all insect organs tested. The highest values for B. germanica cyclophilin mRNA tissue content were found in 6-day-old ovary, followed by brain, testis, and gut (15-30% the content of ovary). The muscle, fat body, and colleterial gland contained the lowest cyclophilin mRNA level (1-5% the content of ovary). There is a developmental pattern of gene expression affecting the embryo stages. These results suggest that this ubiquitously expressed B. germanica cyclophilin is subject to a differential regulation in tissues and during development. Southern-blot analysis of B. germanica DNA shows that only one copy of the CyPA gene is present per genome, whereas at least 20 genes or pseudogenes were detected in the mammalian genome.

Molecular cloning, developmental pattern and tissue expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase of the cockroach Blattella germanica

In insects, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA) synthesizes mevalonate for the production of nonsterol isoprenoids, which are essential for growth and differentiation. To understand the regulation and developmental role of HMG-CoA reductase, we have cloned a full-length HMG-CoA reductase cDNA from the cockroach Blattella germanica. This cDNA clone was isolated using as a probe a partial cDNA of B. germanica HMG-CoA reductase, amplified using the polymerase chain reaction. The composite 3433-bp cDNA sequence contains an open reading frame encoding a polypeptide of 856 amino acids (Mr, 93165). The C-terminal region is more similar to hamster HMG-CoA reductase than is the Drosophila melanogaster enzyme (79% and 69% conserved residues, respectively), and the potential transmembrane domains at the N-terminal region are structurally conservative with both enzymes. The C-terminal region of the B. germanica protein has been expressed as a fusion protein in Escherichia coli and exhibits HMG-CoA reductase activity. Analysis of B. germanica HMG-CoA reductase mRNA levels, reveals a 3.6-kb transcript, that is overexpressed in 4-day-old embryos. Northern-blot analysis of RNA samples from different adult female tissues shows high HMG-CoA reductase mRNA levels in the ovary and lower levels in brain and muscle.