Apolipoprotein J/Clusterin Is a Novel Structural Component of Human Erythrocytes and a Biomarker of Cellular Stress and Senescence

Abstract

BackgroundSecretory Apolipoprotein J/Clusterin (sCLU) is a ubiquitously expressed chaperone that has been functionally implicated in several pathological conditions of increased oxidative injury, including aging. Nevertheless, the biological role of sCLU in red blood cells (RBCs) remained largely unknown. In the current study we identified sCLU as a component of human RBCs and we undertook a detailed analysis of its cellular topology. Moreover, we studied the erythrocytic membrane sCLU content during organismal aging, in conditions of increased organismal stress and accelerated RBCs senescence, as well as during physiological in vivo cellular senescence.Methodology/Principal FindingsBy using a combination of molecular, biochemical and high resolution microscopical methods we found that sCLU is a novel structural component of RBCs extra- and intracellular plasma membrane and cytosol. We observed that the RBCs membrane-associated sCLU decreases during organismal aging or exposure to acute stress (e.g. smoking), in patients with congenital hemolytic anemia, as well as during RBCs in vivo senescence. In all cases, sCLU reduction paralleled the expression of typical cellular senescence, redox imbalance and erythrophagocytosis markers which are also indicative of the senescence- and oxidative stress-mediated RBCs membrane vesiculation.Conclusions/SignificanceWe propose that sCLU at the mature RBCs is not a silent remnant of the erythroid precursors, but an active component being functionally implicated in the signalling mechanisms of cellular senescence and oxidative stress-responses in both healthy and diseased organism. The reduced sCLU protein levels in the RBCs membrane following cell exposure to various endogenous or exogenous stressors closely correlates to the levels of cellular senescence and redox imbalance markers, suggesting the usefulness of sCLU as a sensitive biomarker of senescence and cellular stress.

Uric acid variation among regular blood donors is indicative of red blood cell susceptibility to storage lesion markers: A new hypothesis tested

“…In fact, pathologic levels of the secreted chaperone clusterin were only measured in low‐UA donors in vivo. Clusterin is a marker of oxidative stress and injury in many cells including RBCs . It is involved in several physiologic processes including apoptosis, inflammation, cellular senescence, membrane vesiculation, and in vivo aging .…”

The Molecular Chaperone Apolipoprotein J/Clusterin as a Sensor of Oxidative Stress: Implications in Therapeutic Approaches - A Mini-Review

“…Newer findings adding to these observations have indicated a functional implication of CLU in human erythrocytes in the aged organism, as well as during erythrocyte senescence [47]. Similarly, CLU has been functionally involved in most age-related diseases including cardiovascular and metabolic syndromes, degenerative diseases, inflammation, and cancer [16,28,48].…”

An Efficient Apparatus for Rapid Deoxygenation of Erythrocyte Concentrates for Alternative Banking Strategies

“…Storage lesions include alterations to either morphology (shape changes leading from a discoid to a spherocytic phenotype) or functionality (metabolism and oxygen delivery capacity through an increase in oxygen affinity mediated by a rapid fall in 2,3-diphosphoglycerate concentrations [8–13]). Further lesions occur in stored RBCs which are reversible to some extent, such as potassium leakage to the supernatant and depletion of ATP and DPG stores, while others are not, such as the alteration of lipids and membrane proteins (membrane protein fragmentation and migration to the membrane and/or vesiculation of subsets of structural or antioxidant proteins [9]), which results in more rigid cell structures, increased osmotic fragility, higher haemolytic rates, phosphatidylserine exposure to the outer membrane leaflet, increased vesiculation rate, and reduced oxygen off-loading capacity [8–12, 14, 15]. …”

“…Membrane protein fragmentation [9, 13], storage time-dependent migration of cytosolic proteins to the membrane [9, 14, 15], and increased oxidative stress-related parameters [9, 16] have been also reported to correlate with storage duration. Biochemical studies explicitly suggested that there is considerable room for improvement in the field of RBC biopreservation, especially when considering that the lifespan of RBCs in vivo is approximately 120 days [17].…”