BACKGROUND: T cell dysfunction, which includes exhaustion, anergy, and senescence, is a distinct T cell differentiation state that occurs after antigen exposure. Although T cell dysfunction has been a cornerstone of cancer immunotherapy, its potential in transplant research, while not yet as extensively explored, is attracting growing interest. Interferon regulatory factor 4 (IRF4) has been shown to play a pivotal role in inducing T cell dysfunction. METHODS: A novel ultra-low-dose combination of Trametinib and Rapamycin, targeting IRF4 inhibition, was employed to investigate T cell proliferation, apoptosis, cytokine secretion, expression of T-cell dysfunction-associated molecules, effects of mitogen-activated protein kinase (MAPK) and mammalian target of rapamycin (mTOR) signaling pathways, and allograft survival in both in vitro and BALB/c to C57BL/6 mouse cardiac transplantation models. RESULTS: In vitro , blockade of IRF4 in T cells effectively inhibited T cell proliferation, increased apoptosis, and significantly upregulated the expression of programmed cell death protein 1 (PD-1), Helios, CD160, and cytotoxic T lymphocyte-associated antigen (CTLA-4), markers of T cell dysfunction. Furthermore, it suppressed the secretion of pro-inflammatory cytokines interferon (IFN)-γ and interleukin (IL)-17. Combining ultra-low-dose Trametinib (0.1 mg·kg -1 ·day -1 ) and Rapamycin (0.1 mg·kg -1 ·day -1 ) demonstrably extended graft survival, with 4 out of 5 mice exceeding 100 days post-transplantation. Moreover, analysis of grafts at day 7 confirmed sustained IFN regulatory factor 4 (IRF4) inhibition, enhanced PD-1 expression, and suppressed IFN-γ secretion, reinforcing the in vivo efficacy of this IRF4-targeting approach. The combination of Trametinib and Rapamycin synergistically inhibited the MAPK and mTOR signaling network, leading to a more pronounced suppression of IRF4 expression. CONCLUSIONS Targeting IRF4, a key regulator of T cell dysfunction, presents a promising avenue for inducing transplant immune tolerance. In this study, we demonstrate that a novel ultra-low-dose combination of Trametinib and Rapamycin synergistically suppresses the MAPK and mTOR signaling network, leading to profound IRF4 inhibition, promoting allograft acceptance, and offering a potential new therapeutic strategy for improved transplant outcomes. However, further research is necessary to elucidate the underlying pharmacological mechanisms and facilitate translation to clinical practice.
Animals ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Interferon Regulatory Factors/metabolism* ; Heart Transplantation/methods* ; T-Lymphocytes/immunology* ; Sirolimus/therapeutic use* ; Pyridones/therapeutic use* ; Graft Survival/drug effects* ; Pyrimidinones/therapeutic use* ; Cell Proliferation/drug effects* ; Apoptosis/drug effects* ; Male ; Signal Transduction/drug effects*

Background::Homoharringtonine (HHT) is an effective anti-inflammatory, anti-viral, and anti-tumor protein synthesis inhibitor that has been applied clinically. Here, we explored the therapeutic effects of HHT in a mouse heart transplant model.Methods::Healthy C57BL/6 mice were used to observe the toxicity of HHT in the liver, kidney, and hematology. A mouse heart transplantation model was constructed, and the potential mechanism of HHT prolonging allograft survival was evaluated using Kaplan–Meier analysis, immunostaining, and bulk RNA sequencing analysis. The HHT-T cell crosstalk was modeled ex vivo to further verify the molecular mechanism of HHT-induced regulatory T cells (Tregs) differentiation. Results::HHT inhibited the activation and proliferation of T cells and promoted their apoptosis ex vivo. Treatment of 0.5 mg/kg HHT for 10 days significantly prolonged the mean graft survival time of the allografts from 7 days to 48 days ( P <0.001) without non-immune toxicity. The allografts had long-term survival after continuous HHT treatment for 28 days. HHT significantly reduced lymphocyte infiltration in the graft, and interferon-γ-secreting CD4 + and CD8 + T cells in the spleen ( P <0.01). HHT significantly increased the number of peripheral Tregs (about 20%, P <0.001) and serum interleukin (IL)-10 levels. HHT downregulated the expression of T cell receptor (TCR) signaling pathway-related genes ( CD4, H2-Eb1, TRAT1, and CD74) and upregulated the expression of IL-10 and transforming growth factor (TGF) -β pathway-related genes and Treg signature genes ( CTLA4, Foxp3, CD74, and ICOS). HHT increased CD4 + Foxp3 + cells and Foxp3 expression ex vivo, and it enhanced the inhibitory function of inducible Tregs. Conclusions::HHT promotes Treg cell differentiation and enhances Treg suppressive function by attenuating the TCR signaling pathway and upregulating the expression of Treg signature genes and IL-10 levels, thereby promoting mouse heart allograft acceptance. These findings may have therapeutic implications for organ transplant recipients, particularly those with viral infections and malignancies, which require a more suitable anti-rejection medication.

Objective The oxidative damage of DNA can be caused by excessive levels of Reactive oxygen species(ROS).Monitoring of DNA oxidative damage enables effective evaluation of ROS damage effects.Although the detection of DNA damage effects based on microbial sensor allows quantitative analysis of oxidative damage,the ROS clearance mechanism existed in bacterial will affect the sensitive of detection.The work of this article is to knockout the key genes of ROS clearance mechanism and construct an antioxidant gene-knock-out microbial sensor.The microbial sensor can realize sensitive monitoring of DNA damage effects and then evaluates the damage effects of cells by ROS.Methods The antioxidant damage genes of bacterial ahpCF,katE and katG were knocked out by λ-Red homologous recombination and antioxidant gene-knockout microbial sensor was constructed.The nalidixic acid sodium salt and UV irradiation were used to characterize the performance for monitoring of DNA damage effects.Results The antioxidant gene-knockout microbial sensors ΔahpC,ΔahpCF/ΔkatEG and ΔahpCF/ΔkatE/ΔkatG were constructed successfully.The results showed that the microbial sensor ΔahpCF/ΔkatE/ΔkatGl had the highest sensitive of damage effects and the limit of detection for nalidixic acid sodium salt was 0.40 μmol/L.In addition,1.80 min of UV irradiation(254 nm)was sufficient to induce a significant fluorescent expression effect in the engineered bacteria.Conclusion In this article,antioxidant gene-knockout microbial sensors had been constructed to realize active and sensitive monitoring of DNA damage effects such as DNA damage reagents and UV irradiation.The sensors could provide an active,effective,and sensitive potential monitoring method for future evaluation of radiation effects in space.

Objective:To investigate impacts of soy isoflavones(SIF)on alveolar bone resorption and inflammatory response in periodontitis rats based on Slit homologue 2(Slit2)/P38 mitogen-activated protein kinase(MAPK)signaling pathway.Methods:Rats were separated into Control group,Model group,SIF low-dose group(L-SIF,25 mg/kg)and SIF high-dose group(H-SIF,75 mg/kg),with 10 rats per group,and periodontitis model was established by ligating necks of maxillary first molars of rats with silk thread except for control group.Rats in L-SIF group and H-SIF group were given corresponding doses of SIF by gavage,Control group and Model group were given same amount of normal saline by gavage,once a day,for 4 consecutive weeks.After administration,serum Slit2,TNF-α,IL-6 and IL-1β levels were detected by ELISA;Micro-CT scan was performed to detect distance between cemen-tumenamel junction and alveolar ridge crest(CEJ-ABC),bone mineral density(BMD),bone volume fraction(BV/TV),and alveolar bone loss was evaluated;HE staining and tartrate-resistant acid phosphatase(TRAP)staining were performed to evaluate tissue inflam-mation,bone resorption and osteoclast activity;expressions of osteoprotegerin(OPG)and receptor activator of nuclear factor κB ligand(RANKL)in periodontal tissues were detected by immunohistochemistry(IHC);Western blot was performed to detect protein expressions of Slit2,P38 MAPK and p-P38 MAPK in periodontal tissues.Results:Compared with Control group,serum levels of Slit2,TNF-α,IL-1β,IL-6,CEJ-ABC distance,periodontal histopathological damage score,osteoclast number,positive expression of RANKL,protein level of Slit2 and p-P38 MAPK/P38 MAPK were greatly increased in Model group,BMD,BV/TV and positive ex-pression of periodontal tissues OPG were greatly decreased(all P<0.05);compared with Model group,serum levels of Slit2,TNF-α,IL-1β,IL-6,CEJ-ABC distance,periodontal histopathological damage score,osteoclast number,positive expression of RANKL,pro-tein levels of Slit2 and p-P38 MAPK/P38 MAPK were greatly decreased,BMD,BV/TV and OPG positive expression of periodontal tissues were greatly increased in L-SIF group and H-SIF group(P<0.05),the above indicators in H-SIF group changed greatly better than L-SIF group(P<0.05).Conclusion:SIF can inhibit alveolar bone resorption and inflammatory response in periodontitis rats and improve periodontitis,whose mechanism may be related to inhibition of Slit2/P38 MAPK signaling pathway.

Objective To prepare the chitosan-potD nanoparticles and to evaluate its protective efficacy against pneumococcal nasopharyngeal colonization. Methods potD gene was amplificated from pneumococcal genome and was inserted into pVAX1 expression vectors to construct pVAX1-potD recombinant plasmid which was then transfected into 293T cell using LipofectAMINE 2000 to analyze transient potD gene expression in vitro by RT-PCR and Western blot. Chitosan-potD nanoparticles were freshly prepared by coacervation methods at each time and the characterizations of the nanoparticles were then evaluated. BALB/c mice were immunized with chitosan-potD, naked potD DNA or pVAX1 for 4 times at two-week intervals. Anti-PotD IgG, IgG1 and IgG2a levels in serum and IgA levels in nasal washes, bronchoalveolar lavage fluids (BALF) and middle ear lavages(MEL) were detected by indirect enzyme-linked immunosorbent assay (ELISA). IL-17A, IL-4 and IFN-γ levels in splenocytes were determined by double sandwich ELISA. Mice were intrannsally challenged with Streptococcus pneumoniae ATCC6303, and Pneumococci were recovered from the nasopharyngeal niche at the fifth day after challenge. Results potD gene was successfully amplificated by PCR and the sequence was confimed to be consistent with that in the Genbank. The pVAX1-potD recombinant plasmid was successfully constructed and was expressed in eukaryocytes in vitro. The mean size and zeta potential of chitosan-potD nanoparticles was 430 nm and + 20.5 mv, respectively. Chitosan-potD nanoparticles were not digested by DNase Ⅰ , while naked potD DNA was completely digested. The levels of antibodies inculding IgG, IgG1, IgG2a, IgA and cytokines including IL-17A, IL-4 and IFN-γ were significantly higher in mice immunized with chitosan-potD nanoparticles than mice with naked potD or pVAX1 ( P <0.05) only. More importantly, much less Pneumococci were recovered from mice immunized with chitosan-potD nanoparticles than the other groups(P <0.05). Conclusion Chitosan-potD nanoparticles significantly enhanced the immunogenicity and protection efficacy of DNA vaccines by intranasal immunization and could be used as a potential mucosal vaccine to prevent pneumococcal infection.

Objective To study the immunogenicity of Streptococcus pneumoniae pneumolysin DNA vaccine in Rhesus macaques. Methods The deletion of the gene sequence encoding for the 11 amino acids at the carboxyl terminal of pneumolysin (PN) from its wild type gene (pn) by PCR resulted in a mu-tant pneumolysin gene (pnd). The wild type pn gene encoding PN and the mutant gene (pnd) encoding PND were cloned into pVAX1 vector respectively and then tested as Ppn and Ppnd DNA vaccines. The PN and PND proteins were purified from recombinant E. coli. Rhesus macaques were immunized by intramuscu-larly (i.m.) injection of Ppn or Ppnd DNA vaccine with electroporation (EP). Results Because of the deletion of the gene sequence encoding for the eleven amino acids at the carboxyl terminal of the PN from pn gene, the recombinant PND antigen lost its hemolytic activity while its antigenicity was remained. The spe-cific humoral immunity against pneumolysin was induced by injecting monkey with 500 μg DNA followed by EP. Boosting the Ppn or Ppnd DNA/EP primed animals with corresponding recombinant protein, PN or PND, evoked strong immune response at about 4 fold increase in the antibody titer. Conclusion Specific antibody responses were induced in the monkeys by DNA vaccination and electroporation. The immunogenic-ity of the DNA vaccines were significantly enhanced when PN or PND protein boost was applied 10 d after third DNA vaccination.

OBJECTIVE To prepare pneumolysin(Pn)by genetic engineering and thereby establish the basis for the study of vaccines against otitis media. METHODS A pair of primers including two restriction sites was designed based on the pneumolysin gene sequence reported by Walker in 1987. The pneumolysin gene was PCR-amplified from pneumococcal DNA. The resulting fragment, digested by restriction enzymes, was ligated into the vector PET-28a and then transformed into host cell E.coli JM109(DE3). RESULTS The sequence of the inserted pneumolysin gene was confirmed by DNA sequencing. CONCLUSION The pneumolysin gene was successfully cloned into the host cell.