Hu Xingbin and Liu Qin's Team Reports Programmed Cell Death in Complement-Mediated Hemolysis of Red Blood Cells
Source：Hu Xingbin
2025-06-25
On May 29th, 2025, Dr. Hu Xingbin's team from the Department of Transfusion Medicine at Xijing Hospital, Fourth Military Medical University, and Professor Liu Qin's group from the School of Biotechnology at East China University of Science and Technology published a significant research article in Cell titled "Red blood cells undergo lytic programmed cell death involving NLRP3." This study demonstrates that complement-activated red blood cells (RBCs) not only experience membrane attack complex (MAC) perforation but also undergo programmed cell death mediated by the NLRP3-ASC-Caspase-8-Spectrin-β signaling. The researchers have defined this phenomenon as spectosis (spectrin-dependent cell death), thereby refining classical hemolysis theory and paving the way for new approaches in the prevention, diagnosis, and therapy of hemolytic diseases. Following the publication, Cell featured a Preview titled "ExSPECKt the unexpected: NLRP3-caspase-8-dependent cell death in RBCs" (DOI: 10.1016/j.cell.2025.04.033), and Immunity published a Spotlight titled "Spectosis: Dying for a complement" (DOI: 10.1016/j.immuni.2025.05.017).
Mature human RBCs constitute 70-80% of the body’s total cell population. Jules Bordet was awarded the Nobel Prize in Physiology or Medicine in 1919 for his discovery of complement, while Karl Landsteiner received the same honor in 1934 for his identification of human ABO blood groups. The classical hemolysis theory, which is founded on these discoveries, posits that antigen-antibody reactions within blood groups activate complement, leading to the formation of MAC pores that result in hemoglobin leakage. The free hemoglobin subsequently degrades into heme, which can cause damage to the liver, kidneys, and nervous system. Additionally, a reduced RBC count can compromise tissue oxygenation, posing a significant risk to life. Complement overactivation is also implicated in conditions such as paroxysmal nocturnal hemoglobinuria (PNH). Although complement C3 and C5 inhibitors are currently utilized in clinical settings, approximately 50% of patients exhibit inadequate responses and require blood transfusions. Recent advancements in B-factor inhibitors have demonstrated improved efficacy; however, some patients continue to be non-responsive, indicating the presence of yet undiscovered hemolytic mechanisms. To address this challenge, the research team systematically decoded the intracellular signaling pathways in complement-activated RBCs, with the aim of developing targeted interventions to overcome the limitations of current therapeutic options.
Utilizing integrated multidisciplinary approaches, including molecular biology, live-cell platforms, proteomics, gene editing, bone marrow transplantation, RBC-directed stem cell differentiation, AI structural prediction, and hydrodynamics, this research demonstrates that complement-mediated hemolysis occurs through progressive morphological stages, ultimately leading to the formation of ghost cells, rather than an instantaneous rupture. This programmed cell death involves signal transduction; specifically, complement activation triggers the assembly of the NLRP3-ASC complex, which activates Caspase-8 to cleave the cytoskeletal protein Spectrin-β, resulting in the collapse of the membrane skeleton. Notably, single-base editing of Spectrin-β’s cleavage site allows for escape from Caspase-8-mediated lysis. Therapeutically, the inhibition of NLRP3 or Caspase-8 mitigated hemolysis, with enhanced efficacy observed when both the complement and NLRP3-Caspase-8 pathways were targeted.
This pioneering work presents novel diagnostic and therapeutic strategies for complement-mediated hemolytic diseases, including autoimmune hemolytic anemia and PNH. It expands the immunological perspective on RBCs by revealing that their programmed death is directly linked to NLRP3 and complement activation, thereby providing insights into the roles of RBCs in systemic inflammatory responses. Given that mature RBCs lack nuclei and organelles and differ markedly from nucleated cells in terms of protein composition and regulation, the discovery of NLRP3 functionality in anucleate RBCs opens new avenues for research on inflammasomes and inflammatory responses. While activators such as lipopolysaccharide (LPS), ATP, and crystals are well-established in nucleated cells, this study demonstrates that ABO antigen-antibody reactions can also activate NLRP3, suggesting a potential universal mechanism for NLRP3 activation.
Dr. Hu Xingbin, is an Associate Professor also, from Xijing Hospital served as the lead correspondence author, with Professor Liu Qin and Associate Researcher Chen Shouwen from East China University of Science and Technology as co-corresponding authors. The first author, Associate Researcher Chen Yaozhen from Xijing Hospital, was joined by co-first authors Associate Researcher Chen Shouwen, Associate Senior Technician Liu Zhixin, and Dr. Wang Yafen from Xijing Hospital. Collaborators included researchers from the Kobilka Institute at The Chinese University of Hong Kong-Shenzhen. This work was supported by National Key Research and Development Program of China and the National Natural Science Foundation of China.
Original Article link: https://doi.org/10.1016/j.cell.2025.03.039
Mature human RBCs constitute 70-80% of the body’s total cell population. Jules Bordet was awarded the Nobel Prize in Physiology or Medicine in 1919 for his discovery of complement, while Karl Landsteiner received the same honor in 1934 for his identification of human ABO blood groups. The classical hemolysis theory, which is founded on these discoveries, posits that antigen-antibody reactions within blood groups activate complement, leading to the formation of MAC pores that result in hemoglobin leakage. The free hemoglobin subsequently degrades into heme, which can cause damage to the liver, kidneys, and nervous system. Additionally, a reduced RBC count can compromise tissue oxygenation, posing a significant risk to life. Complement overactivation is also implicated in conditions such as paroxysmal nocturnal hemoglobinuria (PNH). Although complement C3 and C5 inhibitors are currently utilized in clinical settings, approximately 50% of patients exhibit inadequate responses and require blood transfusions. Recent advancements in B-factor inhibitors have demonstrated improved efficacy; however, some patients continue to be non-responsive, indicating the presence of yet undiscovered hemolytic mechanisms. To address this challenge, the research team systematically decoded the intracellular signaling pathways in complement-activated RBCs, with the aim of developing targeted interventions to overcome the limitations of current therapeutic options.
Utilizing integrated multidisciplinary approaches, including molecular biology, live-cell platforms, proteomics, gene editing, bone marrow transplantation, RBC-directed stem cell differentiation, AI structural prediction, and hydrodynamics, this research demonstrates that complement-mediated hemolysis occurs through progressive morphological stages, ultimately leading to the formation of ghost cells, rather than an instantaneous rupture. This programmed cell death involves signal transduction; specifically, complement activation triggers the assembly of the NLRP3-ASC complex, which activates Caspase-8 to cleave the cytoskeletal protein Spectrin-β, resulting in the collapse of the membrane skeleton. Notably, single-base editing of Spectrin-β’s cleavage site allows for escape from Caspase-8-mediated lysis. Therapeutically, the inhibition of NLRP3 or Caspase-8 mitigated hemolysis, with enhanced efficacy observed when both the complement and NLRP3-Caspase-8 pathways were targeted.
This pioneering work presents novel diagnostic and therapeutic strategies for complement-mediated hemolytic diseases, including autoimmune hemolytic anemia and PNH. It expands the immunological perspective on RBCs by revealing that their programmed death is directly linked to NLRP3 and complement activation, thereby providing insights into the roles of RBCs in systemic inflammatory responses. Given that mature RBCs lack nuclei and organelles and differ markedly from nucleated cells in terms of protein composition and regulation, the discovery of NLRP3 functionality in anucleate RBCs opens new avenues for research on inflammasomes and inflammatory responses. While activators such as lipopolysaccharide (LPS), ATP, and crystals are well-established in nucleated cells, this study demonstrates that ABO antigen-antibody reactions can also activate NLRP3, suggesting a potential universal mechanism for NLRP3 activation.
Dr. Hu Xingbin, is an Associate Professor also, from Xijing Hospital served as the lead correspondence author, with Professor Liu Qin and Associate Researcher Chen Shouwen from East China University of Science and Technology as co-corresponding authors. The first author, Associate Researcher Chen Yaozhen from Xijing Hospital, was joined by co-first authors Associate Researcher Chen Shouwen, Associate Senior Technician Liu Zhixin, and Dr. Wang Yafen from Xijing Hospital. Collaborators included researchers from the Kobilka Institute at The Chinese University of Hong Kong-Shenzhen. This work was supported by National Key Research and Development Program of China and the National Natural Science Foundation of China.
Original Article link: https://doi.org/10.1016/j.cell.2025.03.039
