PROGRESSION OF DIABETIC NON-PROLIFERATIVE RETINOPATHY IN TYPE 2 DIABETES MELLITUS: THE CONNECTION WITH THE BLOOD ENDOTHELIAL MONOCYTE-ACTIVATING POLYPEPTIDE-II LEVEL

Relevance. The numerous pro-inflammatory and antiangiogenic properties of endothelial monocyte-activating polypeptide-II (EMAP-II) suggest its possible role in the onset and progression of diabetic non-proliferative retinopathy (DNPR) in type 2 diabetes mellitus (T2DM). Objective – is to determine the blood EMAP-II in the DM2 patients and to establish its connection with the progression of DNPR. Material and methods. We examined 91 patients with DM2 (182 eyes), who were divided into groups: 1st – there was no DNPR in both eyes and 2nd – there was no retinopathy in one eye, and isolated vascular anomalies were noted in the other (ETDRS level 14, 15). The control group included 25 patients of the corresponding age and gender. The patients were re-examined after 1 year. The level of EMAP-II was determined by the enzyme immunoassay in blood plasma once at the beginning of the study. Statistical packages MedStat and MedCalc v.15.1 (MedCalc Software bvba) were used for statistical research. Results. The analysis of clinical and laboratory parameters showed that the initial manifestations of diabetic retinal lesions were manifested in 27.5% of patients after 7.16±1.11 years and were accompanied by greater glycemia. The level of EMAP-II in DM2 was many times higher than in the control, which depended on the presence of diabetic vascular changes in the retina: in patients without changes in the retina (group 1) – by 3.7 times, and in patients with initial vascular anomalies (group 2) – 5.2 times (p<0.001). The level of EMAP-II at the beginning of the study was associated with the progression of diabetic changes in the retina after 1 year – with their presence, it was 1.5 times higher than without them (p<0.001). Stratification by stage of DNPR after 1 year also showed the dependence of the severity of diabetic changes in the retina on the initial level of EMAP-II: in the presence of single vascular anomalies and initial DNPR, it was increased by 3-4 times, while with moderate DNPR – 5.9 times (p<0.001 for all comparisons). Conclusion. Thus, a significant increase in the level of EMAP-II in T2DM was established, and the dependence of the initial diabetic changes in the retina and the degree of their progression in 1 year after the increasing of the blood EMAP-II level.

Roles of aminoacyl-tRNA synthetase-interacting multi-functional proteins in physiology and cancer

Aminoacyl-tRNA synthetases (ARSs) are an important class of enzymes with an evolutionarily conserved mechanism for protein synthesis. In higher eukaryotic systems, eight ARSs and three ARS-interacting multi-functional proteins (AIMPs) form a multi-tRNA synthetase complex (MSC), which seems to contribute to cellular homeostasis. Of these, AIMPs are generally considered as non-enzyme factors, playing a scaffolding role during MSC assembly. Although the functions of AIMPs are not fully understood, increasing evidence indicates that these scaffold proteins usually exert tumor-suppressive activities. In addition, endothelial monocyte-activating polypeptide II (EMAP II), as a cleavage product of AIMP1, and AIMP2-DX2, as a splice variant of AIMP2 lacking exon 2, also have a pivotal role in regulating tumorigenesis. In this review, we summarize the biological functions of AIMP1, EMAP II, AIMP2, AIMP2-DX2, and AIMP3. Also, we systematically introduce their emerging roles in cancer, aiming to provide new ideas for the treatment of cancer.

Targeted Ablation of AIMP1 in Lipopolysaccharide-induced Acute Lung Injury

Background and Hypothesis: Infants with Bronchopulmonary dysplasia (BPD), a chronic lung disease of premature infants, are more susceptible to acute lung injury (ALI). Endothelial-Monocyte Activating Polypeptide II (EMAP II, encoded by Aimp1) is a proinflammatory cytokine that originates from bronchiolar club cells and plays a role in the inflammatory response during BPD development. Prolonged EMAP II exposure has been shown to worsen BPD pathogenesis by activating alveolar macrophages. The targeted ablation of EMAP II in the bronchial club cells of a mouse model (Scgb1a1-ERTCre;Aimp1/fl/fl) is hypothesized to decrease the inflammatory effects of ALI. Experimental Design: Aged-matched littermate mice (ages ranging from 20-25 weeks) with Tamoxifen inducible, Cremediated, bronchial club cell specific ablation of Aimp1 (Scgb1a1-ERTCre;Aimp1/fl/fl, denoted cKO) or with only partial ablation (Scgb1a1-ERT2Cre;Aimp1/fl/wt denoted Ctrl) were given three doses of 120 micro-liters of 20mg/ml tamoxifen over a seven day period. 24 hours after the final dose they were administered a single intratracheal delivery of lipopolysaccharide (LPS) (5mg/kg) 24 hours later immunohistochemistry (IHC) for EMAP II and inflammation was assessed by immunoblotting (IB) for IL-6 in bronchoalveolar lavage (BAL) and cytospin of BAL. Results: IHC showed a decrease of EMAP II expression in the bronchioles of the cKO as compared to ctrl. IL-6 was increased 1.95 fold in the BAL fluid of cKO by IB. Cytospin analysis showed: (Cell Type: Ctrl%, cKo%), Macrophages: 4.66%, 4.70%, Mature neutrophils: 44.44%, 60.25%, Banded Neutrophils: 41.93%, 26.20%, Lymphocytes: 4.30%, 5.10%, Eosinophils: 2.51%, 2.10%, Monocytes: 2.15%, 1.64%. Conclusions: Ablation of bronchial club cell EMAP II, in LPS-induced ALI increased the amount of IL-6 and percentage of mature neutrophils in bronchoalveolar lavage fluid. No significant difference in macrophage were noted in either group. These findings suggest that EMAP II influences immune response time; however, more experiments would be required to establish a link.

A distinct transcriptional profile in response to endothelial monocyte activating polypeptide II is partially mediated by JAK-STAT3 in murine macrophages

Macrophages are important responders to environmental changes such as secreted factors. Among the secreted factors in injured tissues, the highly conserved endothelial monocyte activating polypeptide II (EMAP II) has been characterized to limit vessel formation, to be locally expressed near sites of injury labeling it a “find-me” signal, and to recruit macrophages and neutrophils. The molecular mechanisms mediated by EMAP II within macrophages once they are recruited are unknown. In this study, using a model of partially activated, recruited thioglycollate-elicited peritoneal macrophages, a transient, transcription profile of key functional genes in macrophages exposed to EMAP II was characterized. We found that EMAP II-mediated changes were elicited mainly through signal transducer and activator of transcription 3 (STAT3) as evidenced by increased Y705 phosphorylation and changes in activity and upstream of it, Janus associated kinase (JAK)1/2 upstream. Both inhibition of JAK1/2 and knockdown of Stat3 abrogated a subset of genes that are upregulated by EMAP II. Our results identify a rapid EMAP II-mediated STAT3 activation that coincides with altered pro- and anti-inflammatory gene expression in macrophages.

A Physiological Role for a Moonlighting Protein in Lipopolysaccharide-induced Endotoxemia

Background and Hypothesis: The pathogenesis of Bronchopulmonary Dysplasia (BPD) is multifactorial leading to inflammation. In BPD, Endothelial-Monocyte Activating Polypeptide II (EMAP II, encoded by Aimp1), a moonlighting pro-inflammatory cytokine, is initially found in bronchiolar club cells followed by intra-alveolar GAL-3+ macrophages. Sustained EMAP II mimics BPD, invoking inflammation, alveolar simplification, and macrophage recruitment. Targeted ablation of EMAP II in the recruited macrophages may dampen innate immune response. Experimental Design: Gender-matched, aged-matched littermate mice with myeloid-cell specific ablation of Aimp1 (Lyz2-Cre;Aimp1flox/flox, denoted as Aimp1Δ/Δ) or without (control) were subjected to lipopolysaccharide (LPS)-endotoxemia. Survival rates of co-housed or singly housed mice were measured over 72 hours following a lethal dose (15 mg/kg). Clinical scores (0-6) based on the integrity of their locomotion, fur, and eyes were assigned every 2 hours. Blood and bone marrow smears, average bodyweights, spleen-weights to bodyweights and liver-weights to bodyweights were analyzed. Results: There were no baseline differences in bodyweight, spleen weight:bodyweight, liver weight:bodyweight (p-val = 0.42, 0.46, 0.64). Representative bone marrow and blood smears showed no notable difference. Aimp1[Symbol]/[Symbol] male mice co-housed (dose 15 mg/kg) but not singly housed survived longer than their littermates (median survival: hours); Aimp1[Symbol]/[Symbol] female mice showed a survival advantage (median survival: hours) with lower clinical scores than their littermates. The kinetics of NFKBIA/I[Symbol]B degradation was similar between Aimp1[Symbol]/[Symbol] and control peritoneal macrophages in response to LPS, although there was a higher basal amount in Aimp1[Symbol]/[Symbol]. Conclusion and Potential Impact: Aimp1/EMAP II does play a positive feedback role in innate immunity, potentially in a metabolically and gender-specific role of Aimp1 which remain to be explored.