Evidence that platelet-derived microvesicles may transfer platelet-specific immunoreactive antigens to the surface of endothelial cells and CD34+ hematopoietic stem/ progenitor cells--implication for the pathogenesis of immune thrombocytopenias.

The pathogenesis and tissue damage that accompanies destruction of platelets in immune thrombocytopenias (IT) is still not understood very well and in addition to platelets, other cells (e.g. endothelial cells, CD34+ hematopoietic stem/progenitors) may also become affected. Based on our previous work that platelet antigens (e.g., CD41) may be transferred by platelet-derived microvesicles (PMV) to the surface of other cells, we asked if platelet derived-antigens, especially those that are involved in the formation of anti-platelet antibodies in IT (e.g., against antigen HPA 1 a) could be also transferred by similar mechanism. To address this issue normal human CD34+ cells, human umbilical vein-endothelial cells (HUVEC) and monocytic cell line THP-1 were incubated with PMV derived from HPA1a+ donors. We noticed that the HPA1a antigen is highly expressed on PMV-derived from the HPAla positive platelets and is transferred in PMV-dependent manner to the surface of CD34+ cells, HUVEC and monocytic THP-1 cells. These cells covered with HPA1a positive PMV but not by PMV derived from HPAla negative platelets reacted with anti-HPA1a antibodies derived from the alloimmunized pregnant women. More importantly, human hematopoietic cells that were preincubated with HPA1a+ PMV and subsequently exposed to anti-HPA 1 a serum and human NK cells, become subject to elimination by antibody dependent cell cytotoxicity ADCC. Thus, we postulate that PMV-dependent transfer of antigens may playing an important role in "expanding" the population of target cells that may be affected by anti-platelet antibodies and explain several pathologies that accompany IT (e.g. damage of endothelium, cytopenias)

Evidence that platelet-derived microvesicles may transfer platelet-specific immunoreactive antigens to the surface of endothelial cells and CD34^+ hematopoietic stem/progenitor cells : implication for the pathogenesis of immune thrombocytopenias

The pathogenesis and tissue damage that accompanies destruction of platelets in immune thrombocytopenias (IT) is still not understood very well and in addition to platelets, other cells (e.g. endothelial cells, CD34+ hematopoietic stem/progenitors) may also become affected. Based on our previous work that platelet antigens (e.g., CD41) may be transferred by platelet-derived microvesicles (PMV) to the surface of other cells, we asked if platelet derived-antigens, especially those that are involved in the formation of anti-platelet antibodies in IT (e.g., against antigen HPA 1 a) could be also transferred by similar mechanism. To address this issue normal human CD34+ cells, human umbilical vein-endothelial cells (HUVEC) and monocytic cell line THP-1 were incubated with PMV derived from HPA1a+ donors. We noticed that the HPA1a antigen is highly expressed on PMV-derived from the HPAla positive platelets and is transferred in PMV-dependent manner to the surface of CD34+ cells, HUVEC and monocytic THP-1 cells. These cells covered with HPA1a positive PMV but not by PMV derived from HPAla negative platelets reacted with anti-HPA1a antibodies derived from the alloimmunized pregnant women. More importantly, human hematopoietic cells that were preincubated with HPA1a+ PMV and subsequently exposed to anti-HPA 1 a serum and human NK cells, become subject to elimination by antibody dependent cell cytotoxicity ADCC. Thus, we postulate that PMV-dependent transfer of antigens may playing an important role in "expanding" the population of target cells that may be affected by anti-platelet antibodies and explain several pathologies that accompany IT (e.g. damage of endothelium, cytopenias)

Acute non-hemolytic transfusion reactions and HLA class I antibody: advantages of solid phase assay compared with conventional complement-dependent assay

To evaluate the specific reactivity of HLA Class I antibodies (HLA-I Abs) in acute non-hemolytic transfusion reactions (ANHTRs) using solid phase assays (SPAs) and conventional complement-dependent lymphocyte cytotoxicity test (LCT). ANHTRs are major issues in transfusion medicine. Anti-leukocyte antibodies have been implicated as one of the causative agents of transfusion-related acute lung injury (TRALI) and febrile reaction. Antibodies to HLA Class I and/or Class II (HLA Abs) have been intensively studied using SPAs for TRALI, but not for febrile reaction. About 107 patients and 186 donors associated with ANHTRs were screened for HLA Abs by SPAs such as enzyme-linked immunosorbent assay (ELISA) and the Luminex method. When HLA-I Ab was detected, its specific reactivity was evaluated by comparing its specificity identified by the Luminex method using recombinant HLA molecules and cognate HLA antigens (Ags), as well as LCT with or without anti-human globulin (AHG). The incidences of HLA Abs were as high as 32·7% of patients' serum samples and 16% of donors' serum samples. The incidence of HLA-I Abs did not differ significantly between cases of febrile and allergic reactions. However, HLA-I Abs associated with febrile reaction showed a significantly higher rate of possessing specific reactivity to cognate HLA Ags than those associated with allergic reactions. In addition, the Luminex method enabled the detection of HLA-I Abs much earlier than AHG-LCT in serum samples from a patient with febrile reaction and platelet transfusion refractoriness (PTR). SPAs seem more useful than AHG-LCT for evaluating reactivity of antibodies in ANHTR cases

Editorial: Revisiting the limits of plant life - plant adaptations to extreme terrestrial environments relating to astrobiology and space biology

Plants were essential to the early evolution of terrestrial life and colonization of the young Earth (Kapoor et al., 2023). Plant communities continue to colonize and transform our planet including the newest ecosystems formed post-glaciation, restoring those degraded by human activities and adapting to changing ecological conditions (Huston and Smith, 1987; Chapin et al., 1994; Yuan et al., 2020; Heim et al., 2021). Plants cannot move away from a harmful stimulus, and thus, have evolved remarkable strategies to survive and eventually thrive in harsh environments. Today, humanity is on the verge of exploring our solar system and beyond, eager to discover, answer fundamental questions, and search for extraterrestrial forms of life. Undoubtedly, plants are key organisms to successful deep space missions and independence from the provision of terrestrial resources, whether for long duration interplanetary travel or establishing permanent settlements. With this thought in mind, we have collated articles focusing on terrestrial plants from extreme environments and their adaptations to harsh conditions. This collective knowledge will advance the selection of desired plant characteristics relevant to human space mission

Knockdown of CypA inhibits interleukin-8 (IL-8) and IL-8-mediated proliferation and tumor growth of glioblastoma cells through down-regulated NF-κB

Although cyclophilin A (CypA) has been reported to be over-expressed in cancer cells and solid tumors, its expression and role in glioblastomas have not been studied. Herein, we show that expression of CypA in human glioblastoma cell lines and tissues is significantly higher than in normal human astrocytes and normal counterparts of brain tissue. To determine the role of over-expressed CypA in glioblastoma, stable RNA interference (RNAi)-mediated knockdown of CypA (CypA KD) was performed in gliobastoma cell line U87vIII (U87MG · ΔEGFR). CypA KD stable single clones decrease proliferation, infiltration, migration, and anchorage-independent growth in vitro and with slower growth in vivo as xenografts in immunodeficient nude mice. We have also observed that knockdown of CypA inhibits expression of interleukin-8 (IL-8), a tumorigenic and proangiogenic cytokine. Conversely, enforced expression of CypA in the CypA KD cell line, Ud-12, markedly enhanced IL-8 transcripts and restored Ud-12 proliferation, suggesting that CypA-mediated IL-8 production provides a growth advantage to glioblastoma cells. CypA knockdown-mediated inhibition of IL-8 is due to reduced activity of NF-κB, which is one of the major transcription factors regulating IL-8 expression. These results not only establish the relevance of CypA to glioblastoma growth in vitro and in vivo, but also suggest that small interfering RNA-based CypA knockdown could be an effective therapeutic approach against glioblastomas

Stable interference of EWS–FLI1 in an Ewing sarcoma cell line impairs IGF-1/IGF-1R signalling and reveals TOPK as a new target

BACKGROUND: Ewing sarcoma is a paradigm of solid tumour -bearing chromosomal translocations resulting in fusion proteins that act as deregulated transcription factors. Ewing sarcoma translocations fuse the EWS gene with an ETS transcription factor, mainly FLI1. Most of the EWS–FLI1 target genes still remain unknown and many have been identified in heterologous model systems