Fibroblast growth factor 21 reverses high‐fat diet‐induced impairment of vascular function via the anti‐oxidative pathway in ApoE knockout mice

Circulating endothelial progenitor cells (EPCs), which function in vascular repair, are the markers of endothelial dysfunction and vascular health. Fibroblast growth factor 21 (FGF21), a liver‐secreted protein, plays a crucial role in glucose homeostasis and lipid metabolism. FGF21 has been reported to attenuate the progression of atherosclerosis, but its impact on EPCs under high oxidative stress conditions remains unclear. In vitro studies showed that the β‐klotho protein was expressed in cultured EPCs and that its expression was upregulated by FGF21 treatment. Hydrogen peroxide (H₂O₂)‐induced oxidative stress impaired EPC function, including cell viability, migration and tube formation. Pretreatment with FGF21 restored the functions of EPCs after the exposure to H₂O₂. Administration of N(ω)‐nitro‐L‐arginine methyl ester (L‐NAME), an inhibitor of nitric oxide synthase, inhibited the effects of FGF21 in alleviating oxidative injury by suppressing endothelial nitric oxide synthase (eNOS). In an in vivo study, the administration of FGF21 significantly reduced total cholesterol (TC) and blood glucose levels in apolipoprotein E (ApoE)‐deficient mice that were fed a high‐fat diet (HFD). Endothelial function, as reflected by acetylcholine‐stimulated aortic relaxation, was improved after FGF21 treatment in ApoE‐deficient mice. Analysis of mRNA levels in the aorta indicated that FGF21 increased the mRNA expression of eNOS and upregulated the expression of the antioxidant genes superoxide dismutase (SOD)1 and SOD2 in ApoE‐deficient mice. These data suggest that FGF21 improves EPC functions via the Akt/eNOS/nitric oxide (NO) pathway and reverses endothelial dysfunction under oxidative stress. Therefore, administration of FGF21 may ameliorate a HFD‐induced vascular injury in ApoE‐deficient mice.     

The splicing‐regulatory lncRNA NTRAS sustains vascular integrity

Vascular integrity is essential for organ homeostasis to prevent edema formation and infiltration of inflammatory cells. Long non‐coding RNAs (lncRNAs) are important regulators of gene expression and often expressed in a cell type‐specific manner. By screening for endothelial‐enriched lncRNAs, we identified the undescribed lncRNA NTRAS to control endothelial cell functions. Silencing of NTRAS induces endothelial cell dysfunction in vitro and increases vascular permeability and lethality in mice. Biochemical analysis revealed that NTRAS, through its CA‐dinucleotide repeat motif, sequesters the splicing regulator hnRNPL to control alternative splicing of tight junction protein 1 (TJP1; also named zona occludens 1, ZO‐1) pre‐mRNA. Deletion of the hnRNPL binding motif in mice (Ntras ^∆CA/∆CA) significantly repressed TJP1 exon 20 usage, favoring expression of the TJP1α‐ isoform, which augments permeability of the endothelial monolayer. Ntras ^∆CA/∆CA mice further showed reduced retinal vessel growth and increased vascular permeability and myocarditis. In summary, this study demonstrates that NTRAS is an essential gatekeeper of vascular integrity.     

Mesenchymal stem cell‐conditioned medium attenuates the retinal pathology in amyloid‐β‐induced rat model of Alzheimer's disease: Underlying mechanisms

Amyloid‐beta (Aβ) oligomer is known to contribute to the pathophysiology of age‐related macular degeneration. Herein, we aimed to elucidate the in vivo and in vitro effects of Aβ_1‐42 application on retinal morphology in rats. Our in vivo studies revealed that intracerebroventricular administration of Aβ_1‐42 oligomer caused dysmorphological changes in both retinal ganglion cells and retinal pigment epithelium. In addition, in vitro studies revealed that ARPE‐19 cells following Aβ_1‐42 oligomer application had decreased viability along with apoptosis and decreased expression of the tight junction proteins, increased expression of both phosphor‐AKT and phosphor‐GSK3β and decreased expression of both SIRT1 and β‐catenin. Application of conditioned medium (CM) obtained from mesenchymal stem cells (MSC) protected against Aβ_1‐42 oligomer‐induced retinal pathology in both rats and ARPE‐19 cells. In order to explore the potential role of peptides secreted from the MSCs, we applied mass spectrometry to compare the peptidomics profiles of the MSC‐CM. Gene ontology enrichment analysis and String analysis were performed to explore the differentially expressed peptides by predicting the functions of their precursor proteins. Bioinformatics analysis showed that 3‐8 out of 155–163 proteins in the MSC‐CM maybe associated with SIRT1/pAKT/pGSK3β/β‐catenin, tight junction proteins, and apoptosis pathway. In particular, the secretomes information on the MSC‐CM may be helpful for the prevention and treatment of retinal pathology in age‐related macular degeneration.     

Adiponectin up‐regulates the decrease of myocardial autophagic flux induced by β1‐adrenergic receptor autoantibody partly dependent on AMPK

Cardiomyocytes autophagy is essential for maintaining cardiac function. Our previous studies have found that β₁‐adrenergic receptor autoantibody (β₁‐AA) induced the decreased myocardial autophagic flux, which resulted in cardiomyocyte death and cardiac dysfunction. And other studies demonstrated that β₁‐AA induced the decrease of AMPK phosphorylation, the key hub of autophagy pathway, while adiponectin up‐regulated autophagic flux mediated by AMPK. However, it is not clear whether adiponectin improves the inhibition of myocardial autophagic flux induced by β₁‐AA by up‐regulating the level of AMPK phosphorylation. In this study, it has been confirmed that β₁‐AA induced the decrease of AMPK phosphorylation level in both vivo and vitro. Moreover, pretreatment of cardiomyocytes with AMPK inhibitor Compound C could further reduce the autophagic flux induced by β₁‐AA. Adiponectin deficiency could aggravate the decrease of myocardial AMPK phosphorylation level, autophagic flux and cardiac function induced by β₁‐AA. Further, exogenous adiponectin could reverse the decline of AMPK phosphorylation level and autophagic flux induced by β₁‐AA and even reduce cardiomyocyte death. While pretreated with the Compound C, the adiponectin treatment did not improve the decreased autophagosome formation, but still improved the decreased autophagosome clearance induced by β₁‐AA in cardiomyocytes. This study is the first time to confirm that β₁‐AA could inhibit myocardial autophagic flux by down‐regulating AMPK phosphorylation level. Adiponectin could improve the inhibition of myocardial autophagic flux induced by β₁‐AA partly dependent on AMPK, so as to provide an experimental basis for the treatment of patients with β₁‐AA‐positive cardiac dysfunction.     

MiR‐223‐3p inhibits rTp17‐induced inflammasome activation and pyroptosis by targeting NLRP3

The incidence of syphilis caused by Treponema pallidum subsp pallidum (T pallidum) infection is accompanied by inflammatory injuries of vascular endothelial cells. Studies have revealed that T pallidum infection could induce inflammasome activation and pyroptosis in macrophages. MicroRNA‐223‐3p (miR‐223‐3p) was reported to be a negative regulator in inflammatory diseases. The present study aimed to explore whether miR‐223‐3p regulates T pallidum‐induced inflammasome activation and pyroptosis in vascular endothelial cells, and determine the mechanisms which underlie this process. MiR‐223‐3p levels in syphilis and control samples were determined. The biological function of miR‐223‐3p in the NLRP3 inflammasome and pyroptosis was evaluated in T pallidum‐infected human umbilical vein endothelial cells (HUVECs). We observed a dramatic decrease in miR‐223‐3p levels in syphilis patients (n = 20) when compared to healthy controls (n = 20). Moreover, miR‐223‐3p showed a notable inhibitory effect on recombinant Tp17 (rTP17)‐induced caspase‐1 activation, resulting in decrease in IL‐1β production and pyroptosis, which was accompanied by the release of lactate dehydrogenase (LDH) in HUVECs. Additionally, the dual‐luciferase assay confirmed that NLRP3 is a direct target of miR‐223‐3p. Moreover, NLRP3 overexpression or knockdown largely blocked the effects of miR‐223‐3p on T pallidum‐induced inflammasome activation and pyroptosis in HUVECs. Most importantly, a notable negative correlation was observed between miR‐223‐3p and NLRP3, caspase‐1, and IL‐1β, respectively, in the serum of syphilis patients and healthy controls. Taken together, our results reveal that miR‐223‐3p targets NLRP3 to suppress inflammasome activation and pyroptosis in T pallidum‐infected endothelial cells, implying that miR‐223‐3p could be a potential target for syphilis patients.     

Macrophage‐derived exosomal miR‐4532 promotes endothelial cells injury by targeting SP1 and NF‐κB P65 signalling activation

Atherosclerosis is a complex pathological process involving macrophages, endothelial cells and vascular smooth muscle cells that can lead to ischemic heart disease; however, the mechanisms underlying cell‐to‐cell communication in atherosclerosis are poorly understood. In this study, we focused on the role of exosomal miRNAs in crosstalk between macrophages and endothelial cells and explored the rarely studied molecular mechanisms involved. Our in vitro result showed that macrophage‐derived exosomal miR‐4532 significantly disrupted human umbilical vein endothelial cells (HUVECs) function by targeting SP1 and downstream NF‐κB P65 activation. In turn, increased endothelin‐1 (ET‐1), intercellular cell adhesion molecule‐1 (ICAM‐1) and vascular cell adhesion molecule‐1 (VCAM‐1) and decreased endothelial nitric oxide synthase (eNOS) expression in HUVECs increased attraction of macrophages, exacerbating foam cell formation and transfer of exosomal miR‐4532 to HUVECs. MiR‐4532 overexpression significantly promoted endothelial injury and pretreatment with an inhibitor of miR‐4532 or GW4869 (exosome inhibitor) could reverse this injury. In conclusion, our data reveal that exosomes have a critical role in crosstalk between HUVECs and macrophages. Further, exosomal miR‐4532 transferred from macrophages to HUVECs and targeting specificity protein 1 (SP1) may be a novel therapeutic target in patients with atherosclerosis.     

A circular intronic RNA ciPVT1 delays endothelial cell senescence by regulating the miR‐24‐3p/CDK4/pRb axis

Circular RNAs (circRNAs) have been established to be involved in numerous processes in the human genome, but their function in vascular aging remains largely unknown. In this study, we aimed to characterize and analyze the function of a circular intronic RNA, ciPVT1, in endothelial cell senescence. We observed significant downregulation of ciPVT1 in senescent endothelial cells. In proliferating endothelial cells, ciPVT1 knockdown induced a premature senescence‐like phenotype, inhibited proliferation, and led to an impairment in angiogenesis. An in vivo angiogenic plug assay revealed that ciPVT1 silencing significantly inhibited endothelial tube formation and decreased hemoglobin content. Conversely, overexpression of ciPVT1 in old endothelial cells delayed senescence, promoted proliferation, and increased angiogenic activity. Mechanistic studies revealed that ciPVT1 can sponge miR‐24‐3p to upregulate the expression of CDK4, resulting in enhanced Rb phosphorylation. Moreover, enforced expression of ciPVT1 reversed the senescence induction effect of miR‐24‐3p in endothelial cells. In summary, the present study reveals a pivotal role for ciPVT1 in regulating endothelial cell senescence and may have important implications in the search of strategies to counteract the development of age‐associated vascular pathologies.     

Mitochondrial aconitase 1 regulates age‐related memory impairment via autophagy/mitophagy‐mediated neural plasticity in middle‐aged flies

Age‐related memory impairment (AMI) occurs in many species, including humans. The underlying mechanisms are not fully understood. In wild‐type Drosophila (w¹¹¹⁸ ), AMI appears in the form of a decrease in learning (3‐min memory) from middle age (30 days after eclosion [DAE]). We performed in vivo, DNA microarray, and behavioral screen studies to identify genes controlling both lifespan and AMI and selected mitochondrial Acon1 (mAcon1). mAcon1 expression in the head of w¹¹¹⁸ decreased with age. Neuronal overexpression of mAcon1 extended its lifespan and improved AMI. Neuronal or mushroom body expression of mAcon1 regulated the learning of young (10 DAE) and middle‐aged flies. Interestingly, acetyl‐CoA and citrate levels increased in the heads of middle‐aged and neuronal mAcon1 knockdown flies. Acetyl‐CoA, as a cellular energy sensor, is related to autophagy. Autophagy activity and efficacy determined by the positive and negative changes in the expression levels of Atg8a‐II and p62 were proportional to the expression level of mAcon1. Levels of the presynaptic active zone scaffold protein Bruchpilot were inversely proportional to neuronal mAcon1 levels in the whole brain. Furthermore, mAcon1 overexpression in Kenyon cells induced mitophagy labeled with mt‐Keima and improved learning ability. Both processes were blocked by pink1 knockdown. Taken together, our results imply that the regulation of learning and AMI by mAcon1 occurs via autophagy/mitophagy‐mediated neural plasticity.     

α-Melanocyte-Stimulating Hormone Protects Retinal Vascular Endothelial Cells from Oxidative Stress and Apoptosis in a Rat Model of Diabetes

Aims

Oxidative stress and apoptosis are among the earliest lesions of diabetic retinopathy. This study sought to examine the anti-oxidative and anti-apoptotic effects of α-melanocyte-stimulating hormone (α-MSH) in early diabetic retinas and to explore the underlying mechanisms in retinal vascular endothelial cells.

Methods

Sprague-Dawley rats were injected intravenously with streptozocin to induce diabetes. The diabetic rats were injected intravitreally with α-MSH or saline. At week 5 after diabetes, the retinas were analyzed for reactive oxygen species (ROS) and gene expression. One week later, the retinas were processed for terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and transmission electron microscopy. Retinal vascular endothelial cells were stimulated by high glucose (HG) with or without α-MSH. The expression of Forkhead box O genes (Foxos) was examined through real-time PCR. The Foxo4 gene was overexpressed in endothelial cells by transient transfection prior to α-MSH or HG treatment, and oxidative stress and apoptosis were analyzed through CM-H2DCFDA and annexin-V assays, respectively.

Results

In diabetic retinas, the levels of H₂O₂ and ROS and the total anti-oxidant capacity were normalized, the apoptotic cell number was reduced, and the ultrastructural injuries were ameliorated by α-MSH. Treatment with α-MSH also corrected the aberrant changes in eNOS, iNOS, ICAM-1, and TNF-α expression levels in diabetic retinas. Furthermore, α-MSH inhibited Foxo4 up-regulation in diabetic retinas and in endothelial cells exposed to HG, whereas Foxo4 overexpression abrogated the anti-oxidative and anti-apoptotic effects of α-MSH in HG-stimulated retinal vascular endothelial cells.

Conclusions

α-MSH normalized oxidative stress, reduced apoptosis and ultrastructural injuries, and corrected gene expression levels in early diabetic retinas. The protective effects of α-MSH in retinal vascular endothelial cells may be mediated through the inhibition of Foxo4 up-regulation induced by HG. This study suggests an α-MSH-mediated potential intervention approach to early diabetic retinopathy and a novel regulatory mechanism involving Foxo4.     

PECAM‐1 supports leukocyte diapedesis by tension‐dependent dephosphorylation of VE‐cadherin

Leukocyte extravasation is an essential step during the immune response and requires the destabilization of endothelial junctions. We have shown previously that this process depends in vivo on the dephosphorylation of VE‐cadherin‐Y731. Here, we reveal the underlying mechanism. Leukocyte‐induced stimulation of PECAM‐1 triggers dissociation of the phosphatase SHP2 which then directly targets VE‐cadherin‐Y731. The binding site of PECAM‐1 for SHP2 is needed for VE‐cadherin dephosphorylation and subsequent endocytosis. Importantly, the contribution of PECAM‐1 to leukocyte diapedesis in vitro and in vivo was strictly dependent on the presence of Y731 of VE‐cadherin. In addition to SHP2, dephosphorylation of Y731 required Ca²⁺‐signaling, non‐muscle myosin II activation, and endothelial cell tension. Since we found that β‐catenin/plakoglobin mask VE‐cadherin‐Y731 and leukocyte docking to endothelial cells exert force on the VE‐cadherin–catenin complex, we propose that leukocytes destabilize junctions by PECAM‐1‐SHP2‐triggered dephosphorylation of VE‐cadherin‐Y731 which becomes accessible by actomyosin‐mediated mechanical force exerted on the VE‐cadherin–catenin complex.     

Delta‐like ligand‐4 regulates Notch‐mediated maturation of second heart field progenitor‐derived pharyngeal arterial endothelial cells

Mesodermal progenitors in the second heart field (SHF) express Delta‐like‐ligand 4 (Dll4) that regulates Notch‐mediated proliferation. As cells of SHF lineage mature to assume endocardial and myocardial cell fates, we have shown that Dll4 expression is lost, and the subsequent expression of another Notch ligand Jagged1 regulates Notch‐mediated maturation events in the developing heart. A subset of SHF progenitors also matures to form the pharyngeal arch artery (PAA) endothelium. Dll4 was originally identified as an arterial endothelial‐specific Notch ligand that plays an important role in blood vessel maturation, but its role in aortic arch maturation has not been studied to date secondary to the early lethality observed in Dll4 knockout mice. We show that, unlike in SHF‐derived endocardium and myocardium, Dll4 expression persists in SHF‐derived arterial endothelial cells. Using SHF‐specific conditional deletion of Dll4, we demonstrate that as SHF cells transition from their progenitor state to an endothelial fate, Dll4‐mediated Notch signalling switches from providing proliferative to maturation cues. Dll4 expression maintains arterial identity in the PAAs and plays a critical role in the maturation and re‐organization of the 4th pharyngeal arch artery, in particular. Haploinsufficiency of Dll4 in SHF leads to highly penetrant aortic arch artery abnormalities, similar to those observed in the clinic, primarily resulting from aberrant reorganization of bilateral 4th pharyngeal arch arteries. Hence, we show that cells of SHF lineage that assume an arterial endothelial fate continue to express Dll4 and the resulting Dll4‐mediated Notch signalling transitions from an early proliferative to a later maturation role during aortic arch development.     

Delayed regression of laser‐induced choroidal neovascularization in TNFα‐null mice

We investigated the effects of lacking TNFα on the development and regression of Argon‐laser‐induced choroidal neovascularization (CNV) in mice. We lasered ocular fundus for induction of CNV in both wild‐type (WT) and TNFα‐null (KO) mice. Fluorescence angiography was performed to examine the size of CNV lesions. Gene expression pattern of wound healing‐related components was examined. The effects of exogenous TNFα on apoptosis of human retinal microvascular endothelial cells (HRMECs) and on the tube‐like structure of the cells were investigated in vitro. The results showed that Argon‐laser irradiation‐induced CNV was significantly larger in KO mice than WT mice on Day 21, but not at other timepoints. Lacking TNFα increased neutrophil population in the lesion. The distribution of cleaved caspase3‐labelled apoptotic cells was more frequently observed in the laser‐irradiated tissue in a WT mouse as compared with a KO mouse. Exogenous TNFα induced apoptosis of HRMECs and accelerated regression of tube‐like structure of HRMECs in cell culture. Taken together, TNFα gene knockout delays the regression of laser‐induced CNV in mice. The mechanism underlying the phenotype might include the augmentation of neutrophil population in the treated tissue and attenuation of vascular endothelial cell apoptosis.     

CircHivep2 contributes to microglia activation and inflammation via miR‐181a‐5p/SOCS2 signalling in mice with kainic acid‐induced epileptic seizures

Epilepsy is a chronic brain disease characterized by recurrent seizures. Circular RNA (circRNA) is a novel family of endogenous non‐coding RNAs that have been proposed to regulate gene expression. However, there is a lack of data on the role of circRNA in epilepsy. In this study, the circRNA profiles were evaluated by microarray analysis. In total, 627 circRNAs were up‐regulated, whereas 892 were down‐regulated in the hippocampus in mice with kainic acid (KA)‐induced epileptic seizures compared with control. The expression of circHivep2 was significantly down‐regulated in hippocampus tissues of mice with KA‐induced epileptic seizures and BV‐2 microglia cells upon KA treatment. Bioinformatics analysis predicted that circHivep2 interacts with miR‐181a‐5p to regulate SOCS2 expression, which was validated using a dual‐luciferase reporter assay. Moreover, overexpression of circHivep2 significantly inhibited KA‐induced microglial activation and the expression of inflammatory factors in vitro, which was blocked by miR‐181a‐5p, whereas circHivep2 knockdown further induced microglia cell activation and the release of pro‐inflammatory proteins in BV‐2 microglia cells after KA treatment. The application of circHivep2+ exosomes derived from adipose‐derived stem cells (ADSCs) exerted significant beneficial effects on the behavioural seizure scores of mice with KA‐induced epilepsy compared to control exosomes. The circHivep2+ exosomes also inhibited microglial activation, the expression of inflammatory factors, and the miR‐181a‐5p/SOCS2 axis in vivo. Our results suggest that circHivep2 regulates microglia activation in the progression of epilepsy by interfering with miR‐181a‐5p to promote SOCS2 expression, indicating that circHivep2 may serve as a therapeutic tool to prevent the development of epilepsy.     

Kcnh2 mediates FAK/AKT‐FOXO3A pathway to attenuate sepsis‐induced cardiac dysfunction

ObjectivesMyocardial dysfunction is a significant manifestation in sepsis, which results in high mortality. Even Kcnh2 has been hinted to associate with the pathological process, its involved signalling is still elusive.Materials and methodsThe caecal ligation puncture (CLP) surgery or lipopolysaccharide (LPS) injection was performed to induce septic cardiac dysfunction. Western blotting was used to determine KCNH2 expression. Cardiac function was examined by echocardiography 6 hours after CLP and LPS injection in Kcnh2 knockout (Kcnh2^+/‐) and NS1643 injection rats (n ≥ 6/group). Survival was monitored following CLP‐induced sepsis (n ≥ 8/group).ResultsSepsis could downregulate KCNH2 level in the rat heart, as well as in LPS‐stimulated cardiomyocytes but not cardiac fibroblast. Defect of Kcnh2 (Kcnh2^+/‐) significantly aggravated septic cardiac dysfunction, exacerbated tissue damage and increased apoptosis under LPS challenge. Fractional shortening and ejection fraction values were significantly decreased in Kcnh2^+/‐ group than Kcnh2^+/+ group. Survival outcome in Kcnh2^+/‐ septic rats was markedly deteriorated, compared with Kcnh2^+/+ rats. Activated Kcnh2 with NS1643, however, resulted in opposite effects. Lack of Kcnh2 caused inhibition of FAK/AKT signalling, reflecting in an upregulation for FOXO3A and its downstream targets, which eventually induced cardiomyocyte apoptosis and heart tissue damage. Either activation of AKT by activator or knockdown of FOXO3A with si‐RNA remarkably attenuated the pathological manifestations that Kcnh2 defect mediated.ConclusionKcnh2 plays a protection role in sepsis‐induced cardiac dysfunction (SCID) via regulating FAK/AKT‐FOXO3A to block LPS‐induced myocardium apoptosis, indicating a potential effect of the potassium channels in pathophysiology of SCID.     

3,6'‐disinapoyl sucrose attenuates Aβ1‐42‐ induced neurotoxicity in Caenorhabditis elegans by enhancing antioxidation and regulating autophagy

The aggregation of β‐amyloid (Aβ) has the neurotoxicity, which is thought to play critical role in the pathogenesis of Alzheimer''s disease (AD). Inhibiting Aβ deposition and neurotoxicity has been considered as an important strategy for AD treatment. 3,6''‐Disinapoyl sucrose (DISS), one of the oligosaccharide esters derived from traditional Chinese medicine Polygalae Radix, possesses antioxidative activity, neuroprotective effect and anti‐depressive activity. This study was to explore whether DISS could attenuate the pathological changes of Aβ_1‐42 transgenic Caenorhabditis elegans (C. elegans). The results showed that DISS (5 and 50 μM) treatment significantly prolonged the life span, increased the number of egg‐laying, reduced paralysis rate, decreased the levels of lipofuscin and ROS and attenuated Aβ deposition in Aβ_1‐42 transgenic C. elegans. Gene analysis showed that DISS could up‐regulate the mRNA expression of sod‐3, gst‐4, daf‐16, bec‐1 and lgg‐1, while down‐regulate the mRNA expression of daf‐2 and daf‐15 in Aβ_1‐42 transgenic C. elegans. These results suggested that DISS has the protective effect against Aβ_1‐42‐induced pathological damages and prolongs the life span of C. elegans, which may be related to the reduction of Aβ deposition and neurotoxicity by regulating expression of genes related to antioxidation and autophagy.     

Interleukin‐37 improves T‐cell‐mediated immunity and chimeric antigen receptor T‐cell therapy in aged backgrounds

Aging‐associated declines in innate and adaptive immune responses are well documented and pose a risk for the growing aging population, which is predicted to comprise greater than 40 percent of the world''s population by 2050. Efforts have been made to improve immunity in aged populations; however, safe and effective protocols to accomplish this goal have not been universally established. Aging‐associated chronic inflammation is postulated to compromise immunity in aged mice and humans. Interleukin‐37 (IL‐37) is a potent anti‐inflammatory cytokine, and we present data demonstrating that IL‐37 gene expression levels in human monocytes significantly decline with age. Furthermore, we demonstrate that transgenic expression of interleukin‐37 (IL‐37) in aged mice reduces or prevents aging‐associated chronic inflammation, splenomegaly, and accumulation of myeloid cells (macrophages and dendritic cells) in the bone marrow and spleen. Additionally, we show that IL‐37 expression decreases the surface expression of programmed cell death protein 1 (PD‐1) and augments cytokine production from aged T‐cells. Improved T‐cell function coincided with a youthful restoration of Pdcd1, Lat, and Stat4 gene expression levels in CD4⁺ T‐cells and Lat in CD8⁺ T‐cells when aged mice were treated with recombinant IL‐37 (rIL‐37) but not control immunoglobin (Control Ig). Importantly, IL‐37‐mediated rejuvenation of aged endogenous T‐cells was also observed in aged chimeric antigen receptor (CAR) T‐cells, where improved function significantly extended the survival of mice transplanted with leukemia cells. Collectively, these data demonstrate the potency of IL‐37 in boosting the function of aged T‐cells and highlight its therapeutic potential to overcome aging‐associated immunosenescence.     

LncRNA VEAL2 regulates PRKCB2 to modulate endothelial permeability in diabetic retinopathy

Long non‐coding RNAs (lncRNAs) are emerging as key regulators of endothelial cell function. Here, we investigated the role of a novel vascular endothelial‐associated lncRNA (VEAL2) in regulating endothelial permeability. Precise editing of veal2 loci in zebrafish (veal2 ^gib005Δ8/+) induced cranial hemorrhage. In vitro and in vivo studies revealed that veal2 competes with diacylglycerol for interaction with protein kinase C beta‐b (Prkcbb) and regulates its kinase activity. Using PRKCB2 as bait, we identified functional ortholog of veal2 in humans from HUVECs and named it as VEAL2. Overexpression and knockdown of VEAL2 affected tubulogenesis and permeability in HUVECs. VEAL2 was differentially expressed in choroid tissue in eye and blood from patients with diabetic retinopathy, a disease where PRKCB2 is known to be hyperactivated. Further, VEAL2 could rescue the effects of PRKCB2‐mediated turnover of endothelial junctional proteins thus reducing hyperpermeability in hyperglycemic HUVEC model of diabetic retinopathy. Based on evidence from zebrafish and hyperglycemic HUVEC models and diabetic retinopathy patients, we report a hitherto unknown VEAL2 lncRNA‐mediated regulation of PRKCB2, for modulating junctional dynamics and maintenance of endothelial permeability.