ADAP restraint of STAT1 signaling regulates macrophage phagocytosis in immune thrombocytopenia

Heightened platelet phagocytosis by macrophages accompanied by an increase in IFN-γplay key roles in the etiology of immune thrombocytopenia(ITP);however,it remains elusive how macrophage-mediated platelet clearance is regulated in ITP.Here,we report that adhesion and degranulation-protein adaptor protein(ADAP)restrains platelet phagocytosis by macrophages in ITP via modulation of signal transducer and activator of transcription 1(STAT1)-FcγR signaling.We show that ITP was associated with the underexpression of ADAP in splenic macrophages.Furthermore,macrophages from Adap^(−/−)mice exhibited elevated platelet phagocytosis and upregulated proinflammatory signaling,and thrombocytopenia in Adap^(−/−)mice was mitigated by the depletion of macrophages.Mechanistically,ADAP interacted and competed with STAT1 binding to importinα5.ADAP deficiency potentiated STAT1 nuclear entry,leading to a selective enhancement of FcγRI/IV transcription in macrophages.Moreover,pharmacological inhibition of STAT1 or disruption of the STAT1-importinα5 interaction relieved thrombocytopenia in Adap^(−/−)mice.Thus,our findings not only reveal a critical role for ADAP as an intracellular immune checkpoint for shaping macrophage phagocytosis in ITP but also identify the ADAP-STAT1-importinα5 module as a promising therapeutic target in the treatment of ITP.

Expression pattern and regulation of head-to-head genes Vps36 and Ckap2 during chicken follicle development

Vacuolar protein sorting 36(VPS36),a protein primarily known for its role in the Endosomal Sorting Complex Required for Transport pathway,has recently been shown to be linked to chicken reproduction.Previous research showed that Vps36 is significantly downregulated in sexually mature chicken ovaries compared to immature ones.In this study,using real-time quantitative RT-PCR,we investigated the expression pattern of Vps36 and its head-to-head gene Ckap2 mRNA in chicken follicles.Small white follicles were found to have significantly higher expression of Vps36 and Ckap2 mRNA than any other sized follicles(P<0.05).The expression of Vps36 and Ckap2 mRNA were detected in both granulosa and theca layers of pre-ovulatory follicles,the expression of Ckap2 in theca layers was slightly higher than in granulosa cells.Treatment of small yellow follicles with folliclestimulating hormone and estradiol resulted in a marked decrease of both Vps36 and Ckap2 mRNA(P<0.05);however,progesterone,transforming growth factor-β1 and luteinizing hormone induced no significant changes in Vps36 and Ckap2 mRNA expression in these follicles.These results indicate that the head-to-head genes of Vps36 and Ckap2 exhibit similar expression in chicken follicles and are involved in chicken follicle development.