Suppression of macrophage-mediated xenogeneic rejection by the ectopic expression of human CD177

Advances in Subclinical and Clinical Trials and Immunosuppressive Therapies in Xenotransplantation

Organ transplantation remains the foremost effective intervention for end-stage organ failure. Nevertheless, the scarcity of donors has resulted in prolonged waiting times for countless patients globally. The advent of xenografts presents a promising solution to the organ shortage crisis. Although the utilization of xenografts has a long history, it is only in recent years that breakthroughs in genetically modified pigs have rendered successful xenotransplantation a feasible option. In the past 4 years, numerous subclinical and clinical trials have involved xenotransplantation from genetically modified pigs to humans. However, the outcomes have been disappointing, necessitating a reassessment of basic and preclinical research to address the emerging challenges. Furthermore, immunosuppressive therapies remain essential in xenotransplantation. The range of immunosuppressive agents, encompassing traditional immunosuppressants and monoclonal antibodies such as anti-CD154/CD40 monoclonal antibodies, exhibits considerable diversity. However, the most effective drug combination for achieving optimal efficacy remains elusive. This review will offer a succinct overview of the results from recent clinical and subclinical xenotransplantation trials. Moreover, it will highlight recent advancements in immunosuppressive strategies and discuss potential future research directions in this field.

Regulatory role of CD177+ neutrophils in BMP signaling pathway and its implications for inflammatory bowel disease, sepsis, and intestinal tumors

OBJECTIVES

Inflammatory bowel disease (IBD), sepsis, and intestinal tumors are major health threats. This study aimed to explore the regulatory role of CD177+ neutrophils in the BMP signaling pathway and its impact on the onset, progression, and treatment of these diseases.

METHODS

Gene expression data from the Gene Expression Omnibus (GEO) database for IBD and sepsis were retrieved. Bioinformatics methods like background correction, normalization, and differential expression analysis were used. Weighted gene co-expression network analysis (WGCNA), gene functional enrichment analysis, pan-cancer analysis, single-cell analysis, and in vitro experiments including Caco-2 cell culture, cell proliferation assay (CCK-8), flow cytometry apoptosis analysis, quantitative real-time PCR (qRT-PCR), and plate colony formation assay were performed.

RESULTS

Key genes associated with IBD and sepsis, such as BMP2, BMP4, BMP6, BMP8A, and CD177, were identified. WGCNA in sepsis found two significant modules related to key clinical outcomes. Core gene screening revealed seven shared genes between IBD and sepsis, and enrichment analysis showed involvement in important biological processes and pathways. Pan-cancer analysis showed diverse gene expression patterns and correlations with immune dynamics. Single-cell transcriptomics provided insights into the tumor microenvironment. In vitro experiments demonstrated that CD177 knockdown affected BMP signaling pathway-related gene expression, ROS production, apoptosis, and cell proliferation.

CONCLUSION

CD177+ neutrophils play a crucial role in regulating the BMP signaling pathway in IBD, sepsis, and intestinal tumors. These findings offer potential therapeutic targets, but further clinical validation is required to translate them into effective treatment strategies.

International Xenotransplantation Association (IXA) Position Paper on Kidney Xenotransplantation

Porcine kidney xenotransplantation for end-stage renal disease (ESRD) has reached the stage of clinical testing following major advances in donor pig genetic modifications and effective immunosuppressive strategies through decades of rigorous translational research. Reports of pig kidney xenograft survival beyond 1 year posttranplant in nonhuman primate (NHP) models justify optimism for its potential as an alternative to allotransplantation. In the United States, experimental transplantations of genetically engineered (GE) porcine kidneys into brain-dead subjects and a small number of ESRD patients have shown no evidence of hyperacute rejection and adequate pig kidney function for up to several months. Here we discuss pre-clinical/clinical results, infectious disease, ethical, and regulatory considerations, and propose evidence-based recommendations. For initial clinical trials in kidney xenotransplantation, we make the following recommendations: (i) transplantation with organs from a triple knockout (TKO) donor pig, preferably with added human transgenes, (ii) an immunosuppressive regimen with induction therapy to deplete T (and possibly B) cells, and maintenance therapy based on a cluster of differentiation (CD)40/CD154 co-stimulation pathway blockade, (iii) the patient should be fully acceptable as a candidate for allotransplantation but should be unlikely ever to receive an allograft. Patients aged 60-69 years (extendable to 40-75 years, if one of the criteria mentioned below is present), of blood group B or O, and with diabetes are most at risk in this regard. Other patients who could be considered are (i) those who have lost two or more previous kidney allografts from recurrent disease in the graft, (ii) those with broad human leukocyte antigen (HLA)-reactivity but no evidence of anti-pig antibodies, including swine leukocyte antigen (SLA), and (iii) those with failing vascular access. Clinical pilot studies in carefully and highly selected patients with no alternative therapy will provide the foundation upon which to base subsequent formal expanded clinical trials.

Complement and complement regulatory protein in allogeneic and xenogeneic kidney transplantation

Kidney transplantation is the most optimal treatment for patients with end-stage renal disease, offering significant improvements in patient outcomes over dialysis. However, the potential for immune rejection, where the recipient's immune system attacks the transplanted kidney, can compromise transplant success. The complement system, a key component of the immune response, plays a crucial role in both acute and chronic rejection, including T-cell- and antibody-mediated rejection. Understanding and controlling the complement system is essential for managing rejection and enhancing graft survival and overall success of kidney transplantation. In allogeneic transplantation, complement activation through various pathways contributes to graft damage and failure. Recent advancements in genetic engineering enable the development of transgenic pigs expressing human complement regulatory proteins, which display potential for reducing rejection in xenotransplantation. Despite these advances, the complex mechanisms of complement activation and regulation are not fully understood, necessitating further research. This review examines the role of the complement system in kidney transplantation, explores the latest developments in complement regulatory strategies, and discusses potential therapeutic approaches to improve transplant outcomes.

Thymopentin plays a key role in restoring the function of macrophages to alleviate the sepsis process

Immune dysfunction is one of the leading causes of death of sepsis. How to regulate host immune functions to improve prognoses of septic patients has always been a clinical focus. Here we elaborate on the efficacy and potential mechanism of a classical drug, thymopentin (TP5). TP5 could decrease peritoneal bacterial load, and reduce inflammatory cytokine levels both in the peritoneal lavage fluid (PLF) and serum, alleviate pathological injuries in tissue and organ, coaxed by cecal ligation and perforation (CLP) in mice, ultimately improve the prognosis of septic mice. Regarding the mechanism, using RNA-seq and flow cytometry, we found that TP5 induced peptidoglycan recognition protein 1 (PGLYRP1) expression, increased phagocytosis and restored TNF-α expression of small peritoneal macrophage (SPM) in the septic mice. This may be increased SPM's ability to clear peritoneal bacteria, thereby attenuates the inflammatory response both in the peritoneal cavity and the serum. It was shown that TP5 plays a key role in restoring the function of peritoneal macrophages to alleviate the sepsis process. We reckon that this is closely relevant to SPM phagocytosis, which might involve increased PGLYRP1 expression and restored TNF-α secretion.