Objective To explore the construction of α-1,3-galactosyltransferase (GGTA1) gene-knockout (GTKO) Diannan miniature pigs and the kidney xenotransplantation from pigs to rhesus macaques, and to assess the effectiveness of GTKO pigs. Methods The GTKO Diannan miniature pigs were constructed using the CRISPR/Cas9 gene-editing system and somatic cell cloning technology. The phenotype of GTKO pigs was verified through polymerase chain reaction, Sanger sequencing and immunofluorescence staining. Flow cytometry was used to detect antigen-antibody (IgM) binding and complement-dependent cytotoxicity. Kidney xenotransplantation was performed from GTKO pigs to rhesus macaques. The humoral immunity, cellular immunity, coagulation and physiological indicators of the recipient monkeys were monitored. The function and pathological changes of the transplanted kidneys were analyzed using ultrasonography, hematoxylin-eosin staining, immunohistochemical staining and immunofluorescence staining. Results Single-guide RNA (sgRNA) targeting exon 4 of the GGTA1 gene in Diannan miniature pigs was designed. The pGL3-GGTA1-sgRNA1-GFP vector was transfected into fetal fibroblasts of Diannan miniature pigs. After puromycin selection, two cell clones, C59# and C89#, were identified as GGTA1 gene-knockout clones. These clones were expanded to form cell lines, which were used as donor cells for somatic cell nuclear transfer. The reconstructed embryos were transferred into the oviducts of trihybrid surrogate sows, resulting in 13 fetal pigs. Among them, fetuses F04 and F11 exhibited biallelic mutations in the GGTA1 gene, and F04 had a normal karyotype. Using this GTKO fetal pig for recloning and transferring the reconstructed embryos into the oviducts of trihybrid surrogate sows, seven surviving piglets were obtained, all of which did not express α-Gal epitope. The binding of IgM from the serum of rhesus monkey 20# to GTKO pig PBMC was reduced, and the survival rate of GTKO pig PBMC in the complement-dependent cytotoxicity assay was higher than that of wild-type pig. GTKO pig kidneys were harvested and perfused until completely white. After the left kidney of the recipient monkey was removed, the pig kidney was heterotopically transplanted. Following vascular anastomosis and blood flow restoration, the pig kidney rapidly turned pink without hyperacute rejection (HAR). Urine appeared in the ureter 6 minutes later, indicating successful kidney transplantation. The right kidney of the recipient was then removed. Seven days after transplantation, the transplanted kidney had good blood flow, the recipient monkey's serum creatinine level was stable, and serum potassium and cystatin C levels were effectively controlled, although they increased 10 days after transplantation. Seven days after transplantation, the levels of white blood cells, lymphocytes, monocytes and eosinophils in the recipient monkey increased, while platelet count and fibrinogen levels decreased. The activated partial thromboplastin time, thrombin time and prothrombin time remained relatively stable but later showed an upward trend. The recipient monkey survived for 10 days. At autopsy, the transplanted kidney was found to be congested, swollen and necrotic, with a small amount of IgG deposition in the renal tissue, and a large amount of IgM, complement C3c and C4d deposition, as well as CD68⁺ macrophage infiltration. Conclusions The kidneys of GTKO Diannan miniature pigs may maintain normal renal function for a certain period in rhesus macaques and effectively overcome HAR, confirming the effectiveness of GTKO pigs for xenotransplantation.

This study was aimed at predicting and analyzing the structural and functional properties of the persistence-associated secretory protein PaaX in Mycobacterium tuberculosis(M.tb),identifying its interacting partners,and elucidating its biological roles.Bioinformatics analysis revealed that PaaX comprises 240 amino acids with a molecular mass of 26.54 kDa(C1158H1866N354O334S14).The protein lacks transmembrane domains but contains a signal peptide.Its secondary structure is dominated by α-helices(53.33%),fol-lowed by random coils(36.25%)and extended strands(10.42%),thereby forming a homotetrameric spatial configuration.Potential PaaX-interacting proteins,including Rv0406c,EchA4,EchA5,HsaE,FadE8,LpqP,and End,were predicted.These candidate genes and the paaX gene were cloned into bacterial two-hybrid vectors and co-transformed into Escherichia coli BTH101 cells.Colony PCR and sequencing confirmed the accuracy of the recombinant constructs.Bacterial two-hybrid assays demonstrated direct interac-tions of PaaX with EchA4,HsaE,FadE8,and LpqP.Moreover,gradient dilution experiments indicated that the strongest binding af-finity occurred between PaaX and EchA4.AlphaFold 3 modeling further validated these interactions,thus providing high-confidence predictions of binding interfaces.Our findings revealed that PaaX,a secreted α-helix-rich protein,engages in specific interactions with key metabolic enzymes(EchA4,HsaE,and FadE8)and a lipoprotein(LpqP),thus suggesting its potential involvement in lipid metabolism,stress adaptation,and host-pathogen interactions.This study provides novel insights into PaaX's contribution to M.tb per-sistence and pathogenicity,and highlights its value as a potential target for tuberculosis diagnostics and therapeutic development.

This study was aimed at predicting and analyzing the structural and functional properties of the persistence-associated secretory protein PaaX in Mycobacterium tuberculosis(M.tb),identifying its interacting partners,and elucidating its biological roles.Bioinformatics analysis revealed that PaaX comprises 240 amino acids with a molecular mass of 26.54 kDa(C1158H1866N354O334S14).The protein lacks transmembrane domains but contains a signal peptide.Its secondary structure is dominated by α-helices(53.33%),fol-lowed by random coils(36.25%)and extended strands(10.42%),thereby forming a homotetrameric spatial configuration.Potential PaaX-interacting proteins,including Rv0406c,EchA4,EchA5,HsaE,FadE8,LpqP,and End,were predicted.These candidate genes and the paaX gene were cloned into bacterial two-hybrid vectors and co-transformed into Escherichia coli BTH101 cells.Colony PCR and sequencing confirmed the accuracy of the recombinant constructs.Bacterial two-hybrid assays demonstrated direct interac-tions of PaaX with EchA4,HsaE,FadE8,and LpqP.Moreover,gradient dilution experiments indicated that the strongest binding af-finity occurred between PaaX and EchA4.AlphaFold 3 modeling further validated these interactions,thus providing high-confidence predictions of binding interfaces.Our findings revealed that PaaX,a secreted α-helix-rich protein,engages in specific interactions with key metabolic enzymes(EchA4,HsaE,and FadE8)and a lipoprotein(LpqP),thus suggesting its potential involvement in lipid metabolism,stress adaptation,and host-pathogen interactions.This study provides novel insights into PaaX's contribution to M.tb per-sistence and pathogenicity,and highlights its value as a potential target for tuberculosis diagnostics and therapeutic development.