Interleukin-10 Deficiency Alters Endothelial Progenitor Cell-Derived Exosome Reparative Effect on Myocardial Repair via Integrin-Linked Kinase Enrichment.

Rationale: Systemic inflammation compromises the reparative properties of endothelial progenitor cell (EPC) and their exosomes on myocardial repair, although the underlying mechanism of loss of function of exosomes from inflamed EPCs is still obscure. Objective: To determine the mechanisms of IL-10 (interleukin-10) deficient-EPC-derived exosome dysfunction in myocardial repair and to investigate if modification of specific exosome cargo can rescue reparative activity. Methods and Results: Using IL-10 knockout mice mimicking systemic inflammation condition, we compared therapeutic effect and protein cargo of exosomes isolated from wild-type EPC and IL-10 knockout EPC. In a mouse model of myocardial infarction (MI), wild-type EPC-derived exosome treatment significantly improved left ventricle cardiac function, inhibited cell apoptosis, reduced MI scar size, and promoted post-MI neovascularization, whereas IL-10 knockout EPC-derived exosome treatment showed diminished and opposite effects. Mass spectrometry analysis revealed wild-type EPC-derived exosome and IL-10 knockout EPC-derived exosome contain different protein expression pattern. Among differentially expressed proteins, ILK (integrin-linked kinase) was highly enriched in both IL-10 knockout EPC-derived exosome as well as TNFα (tumor necrosis factor-α)-treated mouse cardiac endothelial cell-derived exosomes (TNFα inflamed mouse cardiac endothelial cell-derived exosome). ILK-enriched exosomes activated NF-κB (nuclear factor κB) pathway and NF-κB-dependent gene transcription in recipient endothelial cells and this effect was partly attenuated through ILK knockdown in exosomes. Intriguingly, ILK knockdown in IL-10 knockout EPC-derived exosome significantly rescued their reparative dysfunction in myocardial repair, improved left ventricle cardiac function, reduced MI scar size, and enhanced post-MI neovascularization in MI mouse model. Conclusions: IL-10 deficiency/inflammation alters EPC-derived exosome function, content and therapeutic effect on myocardial repair by upregulating ILK enrichment in exosomes, and ILK-mediated activation of NF-κB pathway in recipient cells, whereas ILK knockdown in exosomes attenuates NF-κB activation and reduces inflammatory response. Our study provides new understanding of how inflammation may alter stem cell-exosome-mediated cardiac repair and identifies ILK as a target kinase for improving progenitor cell exosome-based cardiac therapies.

High-Throughput Sequencing Reveals Immunological Characteristics of the TRB-/IgH-CDR3 Region of Umbilical Cord Blood.

OBJECTIVE: To compare the differences of immunological characteristics between newborn and adults, we performed high-throughput sequencing to reveal the diversity of umbilical cord blood and adult peripheral blood at both T-cell receptor beta chain (TRB) and immunoglobulin heavy chain (IGH) levels. STUDY DESIGN: High-throughput sequencing was performed to analyze the expression of TRB-CDR3 and IGH-CDR3 in circulating T and B cells isolated from 20 healthy adults, 56 pregnant women, and 40 newborns. RESULTS: Our results revealed different immunological characteristics between newborn and adults, such as distinctive complementarity determining region 3 (CDR3) lengths, usage bias of variable and joining segments, random nucleotide addition, a large number of unique CDR3 peptides, and a greater repertoire diversity. Moreover, each newborn had a distinctive TRB-/IGH-CDR3 repertoire that was independent of the maternal immune status. CONCLUSIONS: This study presents comprehensive, unrestricted profiles of the TRB/IGH-CDR3 repertoire of newborns, pregnant women, and healthy adults at a sequence-level resolution. Our data may contribute to a better understanding of the immune system of newborns and benefit the efficient application of umbilical cord blood transplantation in future.