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The uterine smooth muscle (myometrium) is an immunomodulatory tissue capable of secreting multiple chemokines during pregnancy. We propose that before term labor, chemokines secreted as a result of mechanical stretch of the uterine walls by the growing fetus(es) induce infiltration of maternal monocytes into myometrium, drive their differentiation into macrophages, and induce pro-inflammatory (M1) polarization, leading to labor contractions. This study used high-throughput proteomic mass-spectrometry to investigate the underlying mechanisms and explored the therapeutic potential of a broad-spectrum chemokine inhibitor (BSCI, FX125L) in modulating these effects. Primary myocytes isolated from the myometrium of term pregnant women were subjected in vitro to static mechanical stretch. Proteomic analysis of stretched myocyte-conditioned media (CM) identified significant upregulation of chemokine-related pathways and ECM degradation proteins. CM induced in vitro differentiation of human monocytes to macrophages and polarization into an M1-like phenotype characterized by elevated ROS production. BSCI treatment altered the myocyte secretome, increasing tissue-remodeling and anti-inflammatory proteins, Annexin A1 and TGF-β. BSCI-treated myocyte secretions induced Annexin A1 expression in macrophages and enhanced their phagocytic activity. We conclude that factors secreted by mechanically stretched myocytes induce pro-inflammatory M1 macrophage polarization, while BSCI modulates myocyte secretome, which reprograms macrophages to a homeostatic M2-like phenotype, thus reducing inflammation. When treated with BSCI, M2-polarized macrophages reduced myocyte-driven collagen gel contraction, whereas M1 macrophages enhanced it. This study reveals novel insights into the myocyte–macrophage interaction and identifies BSCI as a promising drug to modulate myometrial activity. We suggest that uterine macrophages may represent a therapeutic target for preventing preterm labor in women.

Efficient allocation of deceased donor organs depends upon effective prediction of immunologic compatibility based on donor HLA genotype and recipient alloantibody profile, referred to as virtual crossmatching (VCXM). VCXM has demonstrated utility in predicting compatibility, though there is reduced efficacy for patients highly sensitized against allogeneic HLA antigens. The recently revised deceased donor kidney allocation system (KAS) has increased transplantation for this group, but with an increased burden for histocompatibility testing and organ sharing. Given the limitations of VCXM, we hypothesized that increased organ offers for highly-sensitized patients could result in a concomitant increase in offers rejected due to unexpectedly positive crossmatch. Review of 645 crossmatches performed for deceased donor kidney transplantation at our center did not reveal a significant increase in positive crossmatches following KAS implementation. Positive crossmatches not predicted by VCXM were concentrated among highly-sensitized patients. Root cause analysis of VCXM failures identified technical limitations of anti-HLA antibody testing as the most significant contributor to VCXM error. Contributions of technical limitations including additive/synergistic antibody effects, prozone phenomenon, and antigens not represented in standard testing panels, were evaluated by retrospective testing. These data provide insight into the limitations of VCXM, particularly those affecting allocation of kidneys to highly-sensitized patients.

Apoptosis is a key pathogenic mechanism in sepsis that induces extensive death of lymphocytes and dendritic cells, thereby contributing to the immunosuppression that characterizes the septic disorder. Numerous animal studies indicate that prevention of apoptosis in sepsis improves survival and may represent a potential therapy for this highly lethal disorder. Recently, novel cell-penetrating peptide constructs such as HIV-1 TAT basic domain and related peptides have been developed to deliver bioactive cargoes and peptides into cells. In the present study, we investigated the effects of sepsis-induced apoptosis in Bcl-x(L) transgenic mice and in wild-type mice treated with an antiapoptotic TAT-Bcl-x(L) fusion protein and TAT-BH4 peptide. Lymphocytes from Bcl-x(L) transgenic mice were resistant to sepsis-induced apoptosis, and these mice had a approximately 3-fold improvement in survival. TAT-Bcl-x(L) and TAT-BH4 prevented Escherichia coli-induced human lymphocyte apoptosis ex vivo and markedly decreased lymphocyte apoptosis in an in vivo mouse model of sepsis. In conclusion, TAT-conjugated antiapoptotic Bcl-2-like peptides may offer a novel therapy to prevent apoptosis in sepsis and improve survival.