Functional Protection by Acute Phase Proteins α ₁ -Acid Glycoprotein and α ₁ -Antitrypsin Against Ischemia/Reperfusion Injury by Preventing Apoptosis and Inflammation

Abstract

Background-Ischemia followed by reperfusion (I/R) causes apoptosis, inflammation, and tissue damage leading to organ malfunction. Ischemic preconditioning can protect against such injury. This study investigates the contribution of the acute phase proteins ␣ 1 -acid glycoprotein (AGP) and ␣ 1 -antitrypsin (AAT) to the protective effect of ischemic preconditioning in the kidney. Methods and Results-Exogenous AGP and AAT inhibited apoptosis and inflammation after 45 minutes of renal I/R in a murine model. AGP and AAT administered at reperfusion prevented apoptosis at 2 hours and 24 hours, as evaluated by the presence of internucleosomal DNA cleavage, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling, and the determination of renal caspase-1-and caspase-3-like activity. AGP and AAT exerted anti-inflammatory effects, as reflected by reduced renal tumor necrosis factor-␣ expression and neutrophil influx after 24 hours. In general, these agents improved renal function. Similar effects were observed when AGP and AAT were administered 2 hours after reperfusion but to a lesser extent and without functional improvement. Moreover, I/R elicited an acute phase response, as reflected by elevated serum AGP and serum amyloid P (SAP) levels after 24 hours, and increased hepatic acute phase protein mRNA levels after 18 hours of renal reperfusion. Conclusions-We propose that the antiapoptotic and anti-inflammatory effects of AGP and AAT contribute to the delayed type of protection associated with ischemic preconditioning and other insults. This mechanism is potentially involved in the course of many clinical conditions associated with I/R injury. Moreover, exogenous administration of these proteins may provide new therapeutic means of treatment.

Analyses of p53 Target Genes in the Human Genome by Bioinformatic and Microarray Approaches

“…In the motif, R ϭ G or A, W ϭ T or A, Y ϭ C or T. Several human genes whose expression is positively regulated by wild-type p53 have been identified. These include mdm2 (5), bax (6), gadd45 (7), proliferating cell nuclear antigen (8), p21/WAF1 (9), insulin-like growth factor-binding protein 3 (IGFBP3) 1 (10), the muscle creatine kinase gene, thrombospondin-1 (11), vascular smooth muscle ␣-actin gene (ACTA) (12), epidermal growth factor receptor (13), and type IV collagenase (MMP-2) (14). Although the number of identified p53 target genes keeps growing, it is conceivable that large fraction of the p53 target genes have not yet been identified.…”

Alpha-1-antitrypsin in cell and organ transplantation

“…Marcondes et al reported that AAT alters the cellular redox state and improves mitochondrial membrane potential while also increasing expression of antioxidant enzymes such as heme oxygenase 1 (Figure 1). 4, 5, 6, 7 Oxidative stress is important in inflammation and IRI, so these activities may contribute to the ability of AAT to promote cell and tissue survival and modulate inflammatory damage 10, 11, 13, 14, 15, 16, 17, 18, 19, 20. Because different types of lymphocytes, and cells in different activation states, differ in dependence on glycolysis vs oxidative phosphorylation, modulation of mitochondrial function may influence the balance between sensitization and tolerance 6…”

“…AAT has been shown to inhibit apoptosis in multiple in vitro and in vivo models 10, 11, 13, 14, 15, 16, 17, 18, 19, 20. Increased cell survival may result not only from stabilization of mitochondrial membranes, but also likely involves direct inhibition of caspases (Figure 1).…”

“…Increased cell survival may result not only from stabilization of mitochondrial membranes, but also likely involves direct inhibition of caspases (Figure 1). 4, 5, 6, 7, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20 The molecular mechanism(s) of this inhibition have not been elucidated; caspases are cysteine proteases, while elastase and other canonical targets of AAT depend on serine. However, immunofluorescence studies have shown colocalization of AAT and activated caspase 3 in apoptotic but not in viable cells 11.…”

Bovine alpha-1 acid glycoprotein can reduce the chemotaxis of bovine monocytes and modulate CD18 expression

“…While being one of the most important binding proteins in plasma [17], AGP also features several immunomodulatory functions [16], such as, for example, the stimulation of human monocytes to release pro-and anti-inflammatory cytokines [36], the inhibition of the chemotactic response of human neutrophils challenged with formyl-methionyl-leucyl-phenylalanine (fMLP) [19,41] and the reduction of platelet aggregation [35]. Moreover, AGP is capable of protecting cells from apoptosis induced by inflammation [7][8][9]. In this study it was first hypothesized that AGP may modulate the chemotactic response of bovine defensive cells, including monocytes and polymorphonuclear cells.…”