Adoptive T cell therapy, particularly T cell receptor-engineered T (TCR-T) cell therapy, holds promise for cancer treatment in solid tumors and hematological malignancies. Conventional lentiviral TCR-T cell therapies face insertional mutagenesis risks, while CRISPR-mediated T cell receptor α constant (TRAC) locus targeting suffers from suboptimal knockin efficiency and chromosome 14 loss. To address these challenges, we introduced a non-viral strategy combining CRISPR-Cas9 electroporation with methotrexate (MTX) metabolic selection. Primary human T cells were engineered to integrate a CMV-pp65-specific TCR and an MTX-resistant dihydrofolate reductase (DHFR)-FS cassette into the TRAC locus via homology-directed repair (HDR). Systematic optimization of electroporation timing, buffer systems, and HDR enhancers achieved initial TCR integration efficiency of ∼20%. Subsequent 6-day MTX treatment enriched engineered cells to ∼70% purity while selectively depleting unedited and chromosomally aberrant clones. Fluorescence in situ hybridization revealed that MTX enrichment reduced CRISPR-associated chromosome 14 loss comparable to unedited T cells. Functionally, TRAC-TCR-T cells exhibited enhanced interferon (IFN)-γ/tumor necrosis factor alpha (TNF-α) secretion and reduced exhaustion markers versus lentiviral counterparts, while maintaining equivalent tumor clearance efficacy in vitro and in xenograft models. In conclusion, this integrated platform mitigates viral vector risks, alleviates concerns of CRISPR-associated genomic instability, and provides a good manufacturing practice (GMP)-compatible approach that may facilitate the development of safer adoptive TCR-T immunotherapies.

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by persistent deficits in social communication and repetitive behaviors. Recent studies have indicated that heterozygous mutations in the mixed lineage leukemia 5 (MLL5) gene are implicated in ASD susceptibility and associated with neurodevelopmental abnormalities. However, the detailed mechanisms remain unclear. Here, we demonstrate that Mll5 haploinsufficiency in mice impairs microglial phagocytosis, drives neuronal hyperexcitability, and recapitulates core ASD-like behaviors. We also show that Mll5 acts as an epigenetic regulator, modulating microglial phagocytosis via the TREM2-SGK3-GSK3β signaling axis, which is associated with deficient glucose metabolism. Furthermore, microglia derived from individual with ASD exhibit parallel reductions in MLL5 expression and phagocytic function. By targeting this pathway, lithium chloride, a GSK3β inhibitor, rescues both microglial phagocytosis deficits and behavioral abnormalities in Mll5 haploinsufficienct mice. Our findings highlight MLL5's critical role in ASD and its potential as a therapeutic target.

Full engraftment and early immune reconstitution of donor hematopoietic stem cells (HSCs) after allogeneic HSC transplantation (allo-HSCT) are crucial. However, effective and safe clinical modality remains lacking. Here, very-late antigen (VLA-4) was identified as a pivotal target for HSC engraftment, and one of its agonists was identified, which significantly promotes donor HSC engraftment and long-term hematopoietic reconstitution by enhancing its self-renewal capacity in allogeneic transplantation and serial xenotransplantation mouse models. Furthermore, the VLA-4 agonist facilitated early immune reconstitution by augmenting T-cell differentiation from HSCs, with the reconstituted immune cells exhibiting potent antiviral effects without exacerbating acute graft-versus-host disease. Mechanistically, VLA-4 A2 activated ERK1/2 phosphorylation to regulate HSC function and lymphoid progenitor differentiation, without inducing leukemogenic gene expression. These findings underscore the significant clinical translational potential of the VLA-4 agonist in promoting HSC engraftment and early cellular immune reconstitution following allo-HSCT.

Malignant tumors with TP53 mutations exhibit poor therapeutic outcomes and high recurrence rates. T cell receptor-based (TCR-based) T cell therapy shows great promise for targeting intracellular cancer neoantigens. However, the immunogenic potential of TP53 hotspot mutations remains poorly characterized. Here, we identified an immunogenic neoantigen derived from the recurrent TP53R248Q mutation, presented by the prevalent HLA-A*11:01 allele. Additionally, we isolated a TP53R248Q-reactive TCR that specifically recognized the TP53R248Q mutation without any discernible cross-activity with cognate WT TP53 or other TP53 mutants at the same codon position. Functional characterization revealed that TP53R248Q TCR-T cells exhibited selective cytotoxicity against tumor cells expressing both the TP53R248Q mutation and HLA-A*11:01 in vitro. Importantly, the adoptive transfer of TP53R248Q TCR-T cells exhibited significant antitumor activity in a clinically relevant patient-derived xenograft model engrafted with TP53R248Q/HLA-A*11:01-positive human tumor tissues. Collectively, our study validates the immunogenicity of the TP53R248Q hotspot mutation and provides a TCR with high therapeutic potential for the development of T cell therapies targeting TP53R248Q/HLA-A*11:01-positive cancers.

Background Malignant tumors with TP53 mutations exhibit poor therapeutic outcomes and high recurrence rates. T cell receptor (TCR)-based T cell therapy shows great promise for targeting intracellular cancer neoantigens. However, the immunogenic potential of TP53 hotspot mutations remains poorly characterized. MethodsToidentify HLA-bound TP53 neoantigens, we employed circular mRNA (cmRNA)-encoded tandem TP53 mutants combined with mild acid elution/mass spectrometry (MAE/MS). TP53R248Q-reactive TCR was then isolated from HLA-A*11:01-positive healthy donor via Tetramer-staining and single-cell TCR sequencing. Next, TP53R248Q TCR-T cells functional avidity was assessed via activation markers expression, cytokine secretion, and cytotoxicity assays. The specificity of TP53R248Q TCR-T cells was validated using alanine/glycine substitution assays, structural modeling, and cross-reactivity screens against human proteome-derived peptides. Additionally, in vivo efficacy was evaluated in cell-derived xenograft (CDX) and patient-derived xenograft (PDX) models engrafted with TP53R248Q/HLA-A*11:01-positive tumor cells. Results We identified a novel immunogenic neoantigen derived from the recurrent TP53R248Q mutation, presented by the prevalent HLA-A*11:01 allele. Additionally, we isolated a TP53R248Q reactive TCR that specifically recognizes the TP53R248Q mutation without any discernable cross-activity to cognate wild-type TP53 or other TP53 mutants at the same codon position. Functional characterization revealed that TP53R248Q TCR-T cells exhibited selective cytotoxicity against tumor cells expressing both TP53R248Q mutation and HLA-A*11:01 in vitro. Importantly, the adoptive transfer of TP53R248Q TCR-T cells exhibited significant anti-tumor activity in a clinically relevant patient-derived xenograft (PDX) model engrafted with TP53R248Q/HLA-A*11:01-positive human tumor tissues. Conclusions This study validates the immunogenicity of the TP53R248Q hotspot mutation and offers a TCR-based therapeutic potential for TP53R248Q/HLA-A*11:01-positive cancer patients. Given the high mutation frequency of TP53R248Q and the widespread prevalence of HLA-A*11:01 across populations, this treatment has broad clinical potential.

Perfluoroalkyl substances (PFASs), persistent environmental contaminants linked to neurodevelopmental toxicity, cannot be adequately modeled by traditional in vitro systems due to their inability to recapitulate multi-organ interactions. To address this limitation, we developed and engineered a tri-organ gut-vascular-nerve axis chip that reconstructs the bidirectional gut-brain communication through an integrated endothelial barrier. Unlike dispersed 2D cultures on d-polylysine plates, our 3D platform supports cross-linked neurite outgrowth, self-assembled microvascular tubules, and a tightly sealed intestinal epithelia, coupled with integrated solid-phase extraction-mass spectrometry for real-time tracking of PFAS dynamics. We demonstrate that intestinal epithelial cells metabolize fluorotelomer alcohols into bioactive fluorotelomer carboxylic acids, which may transit vascular channels to neural compartments, inducing neuronal dysfunction and driving axis-wide alterations in metabolic activity, oxidative stress responses, and inflammatory signaling. This physiologically relevant model provides novel mechanistic insights into PFAS neurotoxicity and establishes a robust organ-on-chip paradigm for environmental toxicology.

Circular mRNA (cmRNA) is particular useful due to its high resistance to degradation by exonucleases, resulting in greater stability and protein expression compared to linear mRNA. T cell receptor (TCR)-engineered T cells (TCR-T) represent a promising means of treating viral infections and cancer. This study aimed to evaluate the feasibility and efficacy of cmRNA in antigen-specific-TCR discovery and TCR-T therapy. Using human cytomegalovirus (CMV) pp65 antigen as a model, we found that the expansion of pp65-responsive T cells was induced more effectively by monocyte-derived dendritic cells transfected with pp65-encoding cmRNA compared with linear mRNA. Subsequently, we developed cmRNA-transduced pp65-TCR-T (cm-pp65-TCR-T) that specifically targets the CMV-pp65 epitope. Our results showed that pp65-TCR could be expressed on primary T cells for more than 7 days. Moreover, both in vitro killing and in vivo CDX models demonstrated that cm-pp65-TCR-T cells specifically and persistently kill pp65-and HLA-expressing tumor cells, significantly prolonging the survival of mice. Collectively, our results demonstrated that cmRNA can be used as a more effective technical approach for antigen-specific TCR isolation and identification, and cm-pp65-TCR-T may provide a safe, non-viral, non-integrated therapeutic approach for controlling CMV infection, particularly in patients who have undergone allogeneic hematopoietic stem cell transplantation.

WDR5 is a highly conserved protein that performs multiple scaffolding functions in the context of chromatin. However, efforts to understand the function of WDR5 in normal tissues physiologically are quite limited so far. In our study, we explored the function of Wdr5 in erythropoiesis and hematopoiesis by using a hematopoietic-specific Wdr5 knockout mouse model. We found that loss of Wdr5 mediated by Vav-iCre leads to embryonic lethality with defective erythropoiesis. In addition, Wdr5-deficiency completely impairs the hematopoietic stem and progenitor cells function and might alter the immunophenotype of these stem cells and progenitors by decreasing c-Kit expression. Collectively, we identified the pivotal role of Wdr5 in fetal hematopoiesis and erythropoiesis as the de novo findings.

Acute graft-versus-host disease (aGVHD) is one of the most common complications of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Janus kinase (JAK) inhibitors are considered as reliable and promising agents for patients with aGVHD. The prophylactic and therapeutic effects of SHR0302, a novel JAK inhibitor, were evaluated in aGVHD mouse models. The overall survival (OS), progression-free survival (PFS), bodyweight of mice, GVHD scores were observed and recorded. The bone marrow and spleen samples of diseased model mice or peripheral blood of patients were analyzed. SHR0302 could prevent and reverse aGVHD in mouse models with preserving graft-versus-tumor effect. Functionally, SHR0302 improved the OS and PFS, restored bodyweight, reduced GVHD scores, and reduced immune cells infiltrated in target tissues. SHR0302 treatment also enhanced the hematopoietic reconstruction compared to the control group. Mechanistically, our results suggested that SHR0302 could inhibit the activation of T cells and modulate the differentiation of helper T (Th) cells by reducing Th1 and increasing regulatory T (Treg) cells. In addition, SHR0302 decreased the expression of chemokine receptor CXCR3 on donor T cells and the secretion of cytokines or chemokines including interleukin (IL)-6, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), CXCL10, etc. thereby destroying the IFN-γ/CXCR3/CXCL10 axis which promotes the progression of GVHD. Besides, SHR0302 decreased the phosphorylation of JAK and its downstream STATs, AKT and ERK1/2, which ultimately regulated the activation, proliferation, and differentiation of lymphocytes. Experiments on primary cells from aGVHD patients also confirmed the results. In summary, our results indicated that JAK inhibitor SHR0302 might be used as a novel agent for patients with aGVHD.

OBJECTIVE To establish a mouse mixed chimerism (MC) model of nonmyeloablative allogeneic bone marrow transplantation(allo-BMT) and explore its affecting factors. METHODS The MC model was established by nonmyeloablative allo-BMT followed by high-dose post-transplant cyclophosphamide (PTCY). 123 mice in the experiments was retrospectively analyzed, and the factors related with the chimerism were explored with the univariate and multivariate logistic regression analysis. A multivariate linear regression was performed by R project to obtain a mathematical model for predicting the chimeric level with relevant affecting factors. RESULTS The model presented mixed chimerism on day 14 after transplantation, and was characterized by a donor lymphocyte infusion (DLI) which significantly promoted donor engraftment on day 15, but transfplantation of PBS in control group was failed. Among 123 mice, 47 (38.21%) mice were MC, while 76 (61.79%) mice were non-MC in 123 mice, respectively; univariate analysis showed that the baseline body weight of mice (P=0.001, 17.84±1.19 g vs 18.50±0.94 g), total body irradiation(TBI，P=0.048) and the using of cyclophosphamide (P=0.16) were affected the chimeric state of mice, while the number of infusing cells and the time of detection showed no significant effects. Multivariate regression analysis showed that under certain conditions, the body weight of mice on day 0 was an independent factor affecting chimeric levels (OR=0.493, 95% CI 0.307-0.791, P=0.003). Through R project multiple linear regression, the math model was achieved, which was chimerism=6.09-12×weight(g)+80.03×TBI(Gy)-4.4×cell-counts (× 107) +0.38×CTX (mg/kg), R2=0.5841, P<0.001. CONCLUSION The experiment presents a method for establishing a mixed chimeric mice model after non-myeloablative bone marrow transplantation and constructs a mathematical model with relevant factors affected chimerism status.

Enhanced understanding of normal and malignant hematopoiesis pathways should facilitate the development of effective clinical treatment strategies for hematopoietic malignancies. Nuclear receptor corepressor 1 (NCoR1) has been implicated in transcriptional repression and embryonic organ development, but its role in hematopoiesis is yet to be fully elucidated. Here, we showed that hematopoietic-specific loss of NCoR1 leads to expansion of the hematopoietic stem cell (HSC) pool due to aberrant cell cycle entry of long-term HSCs under steady-state conditions. Moreover, NCoR1-deficient HSCs exhibited normal self-renewal capacity but severely impaired lymphoid-differentiation potential in competitive hematopoietic-reconstitution assays. Transcriptome analysis further revealed that several hematopoiesis-associated genes are regulated by NCoR1. In addition, NCoR1 deficiency in hematopoietic cells delayed the course of leukemia and promoted leukemia cell differentiation in an MLL-AF9-induced mouse model. NCoR1 and its partner, histone deacetylase 3, can modulate histone acetylation and gene transcription through binding the promoter regions of myeloid-differentiation genes. Our collective results support the critical involvement of NCoR1 in normal and malignant hematopoiesis in vivo.

Trithorax group protein MLL5 is an important epigenetic modifier that controls cell cycle progression, chromatin architecture maintenance, and hematopoiesis. However, whether MLL5 has a role in innate antiviral immunity is largely unknown. Here we show that MLL5 suppresses the RIG-I-mediated anti-viral immune response. Mll5 -deficient mice infected with vesicular stomatitis virus show enhanced anti-viral innate immunity, reduced morbidity, and viral load. Mechanistically, a fraction of MLL5 located in the cytoplasm interacts with both RIG-I and its E3 ubiquitin ligase STUB1, which promotes K48-linked polyubiquitination and proteasomal degradation of RIG-I. MLL5 deficiency attenuates the RIG-I and STUB1 association, reducing K48-linked polyubiquitination and accumulation of RIG-I protein in cells. Upon virus infection, nuclear MLL5 protein translocates from the nucleus to the cytoplasm inducing STUB1-mediated degradation of RIG-I. Our study uncovers a previously unrecognized role for MLL5 in antiviral innate immune responses and suggests a new target for controlling viral infection.

BACKGROUND:Adenosine triphosphate (ATP)-dependent chromatin remodeling SWI/SNF-like BAF and PBAF complexes have been implicated in the regulation of stem cell function and cancers. Several subunits of BAF or PBAF, including BRG1, BAF53a, BAF45a, BAF180, and BAF250a, are known to be involved in hematopoiesis. Baf200, a subunit of PBAF complex, plays a pivotal role in heart morphogenesis and coronary artery angiogenesis. However, little is known on the importance of Baf200 in normal and malignant hematopoiesis.METHODS:Utilizing Tie2-Cre-, Vav-iCre-, and Mx1-Cre-mediated Baf200 gene deletion combined with fetal liver/bone marrow transplantation, we investigated the function of Baf200 in fetal and adult hematopoiesis. In addition, a mouse model of MLL-AF9-driven leukemogenesis was used to study the role of Baf200 in malignant hematopoiesis. We also explored the potential mechanism by using RNA-seq, RT-qPCR, cell cycle, and apoptosis assays.RESULTS:Tie2-Cre-mediated loss of Baf200 causes perinatal death due to defective erythropoiesis and impaired hematopoietic stem cell expansion in the fetal liver. Vav-iCre-mediated loss of Baf200 causes only mild anemia and enhanced extramedullary hematopoiesis. Fetal liver hematopoietic stem cells from Tie2-Cre + , Baf200 f/f or Vav-iCre + , Baf200 f/f embryos and bone marrow hematopoietic stem cells from Vav-iCre + , Baf200 f/f mice exhibited impaired long-term reconstitution potential in vivo. A cell-autonomous requirement of Baf200 for hematopoietic stem cell function was confirmed utilizing the interferon-inducible Mx1-Cre mouse strain. Transcriptomes analysis revealed that expression of several erythropoiesis- and hematopoiesis-associated genes were regulated by Baf200. In addition, loss of Baf200 in a mouse model of MLL-AF9-driven leukemogenesis accelerates the tumor burden and shortens the host survival.CONCLUSION:Our current studies uncover critical roles of Baf200 in both normal and malignant hematopoiesis and provide a potential therapeutic target for suppressing the progression of leukemia without interfering with normal hematopoiesis.

The complement system is becoming increasingly recognized as a key participant in many neurodegenerative diseases of the brain. Complement-deficient animals exhibit reduced neuroinflammation.

Mixed lineage leukemia 5 (MLL5) protein is a trithorax family histone 3 lysine 4 (H3K4) methyltransferase that regulates diverse biological processes, including cell cycle progression, hematopoiesis and cancer. The mechanisms by which MLL5 protein stability is regulated have remained unclear to date. Here, we showed that MLL5 protein stability is cooperatively regulated by O-GlcNAc transferase (OGT) and ubiquitin-specific protease 7 (USP7). Depletion of OGT in cells led to a decrease in the MLL5 protein level through ubiquitin/proteasome-dependent proteolytic degradation, whereas ectopic expression of OGT protein suppressed MLL5 ubiquitylation. We further identified deubiquitinase USP7 as a novel MLL5-associated protein using mass spectrometry. USP7 stabilized the MLL5 protein through direct binding and deubiquitylation. Loss of USP7 induced degradation of MLL5 protein. Conversely, overexpression of USP7, but not a catalytically inactive USP7 mutant, led to decreased ubiquitylation and increased MLL5 stability. Co-immunoprecipitation and co-immunostaining assays revealed that MLL5, OGT and USP7 interact with each other to form a stable ternary complex that is predominantly located in the nucleus. In addition, upregulation of MLL5 expression was correlated with increased expression of OGT and USP7 in human primary cervical adenocarcinomas. Our results collectively reveal a novel molecular mechanism underlying regulation of MLL5 protein stability and provide new insights into the functional interplay among O-GlcNAc transferase, deubiquitinase and histone methyltransferase.

Trithorax group (TrxG) proteins play critical roles in transcriptional activation by promoting methylation of histone H3 Lysine 4 (H3K4), but the precise functions of the individual TrxG members during embryonic differentiation are not fully understood. Here we show that Mll2, a TrxG member, is required for proliferation but is dispensable for maintaining the pluripotency of mouse embryonic stem cells (ESCs). In addition, differentiation of ESCs toward mesodermal and endodermal lineages is severely altered and, in particular, the cardiac lineage differentiation of ESCs is completely abolished in the absence of Mll2. Moreover, the expression of core cardiac transcription factors and the levels of H3K4 tri-methylation of these cardiac-specific promoters are significantly decreased by the loss of Mll2. Taken together, our results reveal a critical role for Mll2 in proliferation and cardiac lineage differentiation of mouse ESCs, and provide novel molecular insight into the mechanisms of cardiac development and disease.

The embryonic stem cells(ESC) have been successfully used to study the development of the hematopoietic cell lineages.During the past decades,an increasing number of studies have demonstrated the in vitro hematopoietic differentiation systems of both mouse and human ESC cells,which provide useful tools for elucidating the regulation of hematopoietic development.In this review,we summarize the recent progress in the hematopoietic differentiation from pluripotent embryonic stem cells.

Trithorax group proteins methylate lysine 4 of histone 3 (H3K4) at active gene promoters. MLL5 protein, a member of the Trithorax protein family, has been implicated in the control of the cell cycle progression; however, the underlying molecular mechanism(s) have not been fully determined. In this study, we found that the MLL5 protein can associate with the cell cycle regulator "host cell factor" (HCF-1). The interaction between MLL5 and HCF-1 is mediated by the "HCF-1 binding motif" (HBM) of the MLL5 protein and the Kelch domain of the HCF-1 protein. Confocal microscopy showed that the MLL5 protein largely colocalized with HCF-1 in the nucleus. Knockdown of MLL5 resulted in reduced cell proliferation and cell cycle arrest in the G1 phase. Moreover, down-regulation of E2F1 target gene expression and decreased H3K4me3 levels at E2F1-responsive promoters were observed in MLL5 knockdown cells. Additionally, the core subunits, including ASH2L, RBBP5, and WDR5, that are necessary for effective H3K4 methyltransferase activities of the Trithorax protein complexes, were absent in the MLL5 complex, suggesting that a distinct mechanism may be used by MLL5 for exerting its H3K4 methyltransferase activity. Together, our findings demonstrate that MLL5 could associate with HCF-1 and then be recruited to E2F1-responsive promoters to stimulate H3K4 trimethylation and transcriptional activation, thereby facilitating the cell cycle G1 to S phase transition.