Severe aplastic anemia (SAA) is a critical hematological disorder characterized by bone marrow hematopoietic failure and abnormal immune microenvironment. Longitudinal studies have emphasized the immune-mediated damage to hematopoietic stem/progenitor cells (HSPC), yet the differences in cell response, particularly the underlying programs of megakaryocyte-erythroid progenitor cells (MEP) in bone marrow microenvironment (BME) remain poorly understood. Herein, we constructed single-cell atlas by integrating scRNA-seq data of bone marrow mononuclear cells (BM-MNCs) in healthy control (Ctrl), non-SAA and SAA. Milo and Augur were respectively used for evaluating the changes in the abundance of disease-related cell states and ranking the sensitivity of cell type disease responses. Subsequently, independent bulk RNA-seq data were used for GSEA verification and WGCNA co-expression network analysis of MEP signatures. Cell-to-cell communication alterations were inferred through CellChat, while HSC/MPP-MEP-Ery differentiation trajectories, fate probabilities and regulatory module remodeling were evaluated by combining Monocle3, CellRank, impairment score and SCENIC/pySCENIC. Generally, a total of 18 sub-clusters in BM-MNCs were identified, and MEP was a highly disturbed progenitor cell in SAA with the highest Augur AUC score (0.852). SAA-MEP exhibited enhanced stress and mitochondrial respiration-related programs, while ribosome generation and protein translation-related processes were downregulated. The SAA-MEP signature was associated with immune activation, antigen presentation, protein degradation, and apoptosis-related modules enhancement. Meanwhile, abnormal HSC/MPP-MEP-Ery differentiation trajectories were observed in SAA. In details, the translation/rubisynthesis programs related to erythroid fate in SAA exhibited a loss of correlation, while DNA replication, RNA splicing, and chromosome maintenance-related programs were enhanced. Overall, these data revealed the multifaceted variations in the BME remodeling of SAA and the abnormal erythroid differentiation of MEP, which indicated the vulnerable state of MEP influenced by both the alteration of exogenous communication signals and the remodeling of intrinsic regulatory programs. Taken together, this study provides novel basis for understanding erythroid hematopoietic failure in SAA.

Acquired aplastic anemia (AA) is a prevalent nonmalignant hematologic disorder characterized by primary bone marrow failure (BMF), ineffective hematopoiesis, and consequent pancytopenia associated with abnormal immune responses and autoreactive T lymphocyte-mediated dysfunction of hematopoietic stem and progenitor cells (HSPCs). Recently, we observed a remarkable decrease in serum irisin levels in patients with AA, as well as beneficial effects of irisin administration on HSPC stemness and pancytopenia-related dysimmunity during BMF; however, the optimal protective effect of irisin on AA remains unknown. For this purpose, we further dissected the potential relationship between low irisin concentration and key T-cell subsets in patients and systematically compared the therapeutic effects of irisin pretreatment and irisin treatment in an AA mouse model using multifaceted analyses (e.g., body condition, peripheral blood cell counts, conventional staining, inflammatory cytokine detection, cell viability analysis of HSPCs, and T-cell subset analysis). Consistent with the decline in irisin concentration in AA, we further verified correlations with the indicated T-cell subsets. Using our well-established disease model, we found that AA mice with irisin pretreatment (Days -1 to 27) showed enhanced protective effects over those with irisin treatment (Days 7-27), including improved body condition and peripheral blood cell counts, reduced proinflammatory cytokines, rescue of HSPC stemness, and pancytopenia-related T-cell imbalance. Collectively, our data indicated the superiority of irisin pretreatment in alleviating AA-associated autoreactive T lymphocyte-mediated HSPC dysfunction and pancytopenia. Our findings provide new insights for the development of novel irisin-based regimens with enhanced protective effects against AA.

Scalar-induced gravitational waves (SIGWs) provide a direct probe of the enhanced primordial curvature perturbations that may also produce primordial black holes (PBHs). We forecast the capability of the space-based gravitational-wave observatory Taiji to search for an SIGW background generated by a broken-power-law curvature spectrum. A signal-injection study is used to validate the analysis pipeline, after which a pure-noise realization is employed to derive projected upper limits on the curvature-spectrum parameters. We translate these limits into constraints on the PBH abundance using the nonlinear compaction function, critical collapse, and the joint Gaussian distribution of the compaction amplitude and curvature at its peak. The resulting projected 95% upper limits on the PBH dark-matter fraction satisfy f_PBH^95%<1 over PBH masses from approximately 6.2×10^-18 M_⊙ to 1.7×10^-8 M_⊙. We compare the forecast with representative Hawking-evaporation and microlensing bounds. In part of the asteroid-mass interval, the projected Taiji limit is more restrictive than the current Subaru Hyper Suprime-Cam (HSC) microlensing constraint.

Acute lung injury (ALI) is a severe lung condition that can lead to acute respiratory failure. Given their anti-inflammatory and reparative properties, mesenchymal stem cells (MSCs) represent a promising therapeutic approach. This study aims to investigate the therapeutic potential and underlying mechanisms of interleukin-1 receptor antagonist (IL-1Ra) overexpressing MSCs (oeIL-1Ra-MSCs) in a murine ALI model. Following ALI induction, mice were treated with either oeIL-1Ra-MSCs or control MSCs (Mock-MSCs). The therapeutic effects on the lungs were evaluated using micro-CT, histopathology, and analysis of pro-inflammatory cytokines. Additionally, immunohistochemical and immunofluorescent analyses were performed on lung tissue, and mRNA sequencing was conducted to compare gene expression profiles between oeIL-1Ra-MSCs and Mock-MSCs. oeIL-1Ra-MSCs more effectively improved lung function in ALI mice, as evidenced by reduced patchy opacities, increased lung volume, decreased injury scores, and attenuated pulmonary edema. The treatment also significantly suppressed inflammation by decreasing pro-inflammatory cytokines and reducing macrophage and neutrophil infiltration. Furthermore, oeIL-1Ra-MSCs promoted tissue repair by enhancing the proliferation of alveolar type II epithelial (ATII) cells. mRNA sequencing identified elevated expression of insulin-like growth factor 2 (IGF2) in oeIL-1Ra-MSCs compared with Mock-MSCs. In vitro studies confirmed that IGF2 mediated the therapeutic effects partly by regulating the AKT/Bcl-2 and AKT/GSK-3β/Cyclin D1 signaling pathways, thereby inhibiting apoptosis and promoting the proliferation of ATII cells. In conclusion, IL-1Ra overexpression markedly enhances the therapeutic efficacy of MSCs in ALI by dual mechanisms: IL-1Ra secretion to counteract inflammation, and subsequent secretion of IGF2 to drive tissue regeneration, highlighting their strong potential for ALI.

The rapid emergence of multidrug-resistant (MDR) bacteria poses a critical challenge in hospital-acquired infections, particularly methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. Antimicrobial peptides (AMPs) are promising therapeutic candidates due to their broad-spectrum antibacterial activity. Here, we report AMP-36, a 36-amino acid antimicrobial peptide rationally designed and synthesized from SAAP-148, exhibits potent antibacterial activity. AMP-36 displayed low micromolar minimum inhibitory concentrations and rapid bactericidal activity in vitro, achieving near-complete bacterial killing within 8 h. In the murine pneumonia model, AMP-36 significantly reduced bacterial burden in bronchoalveolar lavage fluid (BALF) and markedly alleviated lung inflammation. Scanning electron microscopy (SEM) revealed pronounced disruption of MRSA cell membranes following AMP-36 treatment, indicating membrane damage as the primary antibacterial mechanism. Transcriptomic analysis further demonstrated its broad transcriptional alterations. Collectively, these findings highlight AMP-36 as a promising therapeutic candidate for MRSA pneumonia and provide mechanistic insights into its antimicrobial action.

Multiple myeloma (MM) is an incurable plasma cell malignancy. Dyskerin pseudouridine synthase 1 (DKC1), a nucleolar protein, is essential for RNA modification and cellular homeostasis, yet its role in MM remains unclear. Prognostic significance of DKC1 in MM patients was evaluated using the MMRF CoMMpass and GEO datasets. Functional effects of DKC1 knockdown or overexpression were investigated via in vitro proliferation, apoptosis assays and in vivo xenografts. Transcriptomic profiling and CMC-based pseudouridine (Ψ) mapping were used to define DKC1-mediated regulation of ATF5. Elevated DKC1 expression was identified as an independent prognostic marker of poor outcomes in MM patients. Decision tree analysis demonstrated that integrating DKC1 expression further refined prognostic stratification beyond the ISS system. Functional assays revealed that DKC1 promoted MM cell proliferation, survival and colony formation, while DKC1 knockdown or pharmacologic inhibition with pyrazofurin significantly reduced MM cell proliferation and colony formation, increased apoptosis in vitro, and suppressed tumor growth in xenograft models. RNA sequencing analysis identified ATF5 as a downstream target of DKC1, and subsequent experimental validation confirmed that DKC1 exerts part of its function through ATF5. We further demonstrated that DKC1 knockdown reduces ATF5 mRNA stability through impaired pseudouridylation. Site-specific Ψ modifications on ATF5 mRNA confirmed a direct post-transcriptional regulatory mechanism. DKC1 drives MM progression by promoting ATF5 stability through pseudouridylation, thereby enhancing myeloma cell proliferation and survival. These findings highlight that DKC1 may be used as a potential biomarker for risk stratification and a promising therapeutic target in MM.

TP53 mutations are associated with early progression and poor prognosis in diffuse large B cell lymphoma (DLBCL). This systematic review and meta-analysis evaluated remission outcomes of different therapies in TP53-mutated (TP53m) DLBCL. In total, 33,762 records were identified, and 31 studies comprising 1,164 patients with TP53m DLBCL were included. In the newly diagnosed (ND) setting, among patients treated with targeted therapy (TT) plus chemotherapy, the pooled complete remission (CR) rate was 60% (95% CI: 50%-69%; n = 552; I 2 = 75.7%) and the pooled overall remission rate (ORR) was 80% (95% CI: 74%-86%; n = 202; I 2 = 0%). In the relapsed/refractory (R/R) setting, among patients treated with chimeric antigen receptor T cell (CAR-T) therapy, the pooled CR rate was 39% (95% CI: 24%-54%; n = 139; I 2 = 64.2%) and the pooled ORR was 77% (95% CI: 43%-99%; n = 131; I 2 = 94.1%). TT plus chemotherapy and CAR-T-based therapy show encouraging activity in TP53-mutated DLBCL, but larger prospective studies are required to define their clinical roles.

Aplastic anemia (AA) is a debilitating disorder marked by bone marrow failure, frequently associated with dysregulated T cell activity. The present study explored the therapeutic potential of anti-CD3 antibody-modified calcium silicate nanoparticles loaded with novel 7H-pyrrolo[2,3-d]pyrimidine derivatives (antiCD3-pCaSiNP@NPDP) for AA treatment. Whole-transcriptome sequencing and bioinformatics analysis identified interleukin-2-inducible T-cell kinase (ITK) as a critical regulator of T cell function in AA. In vitro experiments demonstrated that ITK enhances T cell proliferation and promotes differentiation toward inflammatory subsets, thereby contributing to disease progression. The newly developed NPDP derivatives effectively inhibited ITK activity. Targeted delivery of NPDP via antiCD3-pCaSiNP nanoparticles selectively suppressed ITK expression in T cells, resulting in reduced inflammatory T cell proliferation and increased regulatory T cell populations. In an AA mouse model, administration of antiCD3-pCaSiNP@NPDP nanoparticles markedly improved hematopoietic recovery and immune balance. The findings indicate that nanoparticle-mediated ITK inhibition represents a promising therapeutic strategy for restoring immune and bone marrow function in AA.

RNA 5-methylcytosine (m5C) modification is a crucial epigenetic regulation, and aberrant m5C methylation is associated with the pathogenesis of certain cancers. However, the role and regulatory mechanisms of RNA m5C modification in multiple myeloma (MM) remain unclear. This study aimed to investigate the function and regulatory mechanisms of the primary m5C methyltransferase, NOP2/Sun RNA methyltransferase family member 2 (NSUN2), in MM. The results demonstrated NSUN2 overexpression in patients with MM, and higher NSUN2 levels were associated with poorer outcomes. In addition, elevated global RNA m5C levels were identified in specimens from MM patients, and NSUN2 knockdown decreased RNA m5C levels. Furthermore, NSUN2 knockdown suppressed cell proliferation, promoted apoptosis in vitro, and restrained the progression of xenograft tumors in vivo. Mechanistically, m5C methylated RNA immunoprecipitation (meRIP)-sequencing and RIP-quantitative polymerase chain reaction (RIP-qPCR) assays were applied to screen the candidate targets of NSUN2-mediated m5C modification and huntingtin interacting protein 1 (HIP1) was identified as the target. NSUN2-mediated m5C methylation upregulated HIP1 by enhancing HIP1 mRNA stability. Moreover, HIP1 overexpression counterbalanced the inhibitory effect of NSUN2 knockdown. In conclusion, we propose a novel mechanistic insight into the NSUN2/m5C-HIP1 signaling axis that contributes to the pathogenesis of MM. Thus, NSUN2 can be a novel prognostic biomarker in patients with MM and targeting NSUN2 may be a promising therapeutic strategy.

Hemorrhagic cystitis (HC), a frequent complication of hematopoietic stem cell transplantation (HSCT), significantly affects quality of life and may worsen prognosis. Mesenchymal stem cells (MSCs) are known for their anti-inflammatory and tissue-regenerative properties. IL-1 receptor antagonist (IL-1Ra) blocks IL-1α and IL-1β by binding IL-1 receptors, offering potential therapeutic benefits. The aim of this study was to explore the therapeutic effect of MSCs overexpressing IL-1Ra on HC and investigate the underlying mechanisms. MSCs were isolated from human umbilical cord tissues, and IL-1Ra-overexpressing MSCs (oeIL-1Ra-MSCs) were generated using lentiviral transfections. HC was induced in rats by cyclophosphamide administration. Rats received tail vein injections of either oeIL-1Ra-MSCs or control MSCs (Mock-MSCs). Hematuria and bladder tissue changes were assessed using test strips and hematoxylin eosin (HE) staining. Immunohistochemistry detected molecular changes in bladder tissues. Gene expression differences between the two MSC groups were analyzed by mRNA sequencing and ChIP techniques. Treatment with oeIL-1Ra-MSCs significantly alleviated hematuria and reduced bladder edema and hemorrhage, and reduced mRNA expression levels of IL-1β, IL-6, and TNF-α in bladder tissues, compared with those in the Mock-MSC treatment group. Immunohistochemical staining showed a higher presence of CD105-positive cells (a marker for human MSCs) and CD31-positive vessels in bladder tissues treated with oeIL-1Ra-MSCs, indicating enhanced MSC migration and vascular stability. In vitro migration assay demonstrated a higher migration capacity of IL-1Ra overexpressing MSCs compared with that of control MSCs. Moreover, angiopoietin-1 (Ang-1) expression increased, while Angiopoietin-2 (Ang-2) expression decreased in bladder tissues treated with oeIL-1Ra-MSCs, suggesting enhanced blood vessel stabilization. Conditioned medium from oeIL-1Ra-MSC cultures stimulated human umbilical vein endothelial cell (hUVEC) migration, proliferation, and angiogenesis more effectively compared with that in control MSCs. mRNA sequencing revealed elevated HtrA3 expression in oeIL-1Ra-MSCs compared with that in control MSCs. Molecular analysis suggested that IL-1Ra overexpression in MSCs upregulated HtrA3 expression through inhibition of the JNK-c-Jun pathway and activation of the ERK–Egr-1 pathway. Overexpression of IL-1Ra significantly enhances the therapeutic efficacy of MSCs in HC by promoting MSC migration to damaged bladder tissues, suppressing inflammation, stabilizing blood vessels, and upregulating angiogenesis via activation of HtrA3 signaling pathways.

BackgroundTelomerase activation is essential to malignant transformation and progression including uterine corpus endometrial carcinoma (UCEC), while telomerase co-factor DKC1-mediated RNA pseudouridylation is required for functional telomerase by stabilizing telomerase RNA component (TERC) and its upregulation occurs in many cancers. Surprisingly, there is only one publication studying DKC1 in UCEC, which shows its significant downregulation.ObjectiveDKC1 expression, its role in the UCEC molecular pathogenesis and clinical implications were comprehensively investigated.MethodsThirty UCEC patients were recruited to determine DKC1 expression in both tumors and non-tumorous endometrial tissues (NT) using immunohistochemistry. Four UCEC cohorts from TCGA and GSE datasets were analyzed for DKC1 expression and its impacts on clinic-pathological, molecular, genomic and immune landscapes.ResultsImmunohistochemistry analyses showed significantly increased DKC1 expression in UCEC tumors than in NTs and its highest level was observed in high-grade tumors. For the TCGA cohort, DKC1 mRNA and protein levels increased significantly in tumors compared with that in NTs. DKC1 mRNA levels positively correlated with TERC and telomerase activity. Higher DKC1 expression predicted shorter patient overall and progression-free survival. DKC1 copy number alterations were frequent in UCEC tumors. Estrogen treatment of UCEC cells upregulated DKC1 expression while medroxyprogesterone inhibited its expression. DKC1-high UCEC tumors exhibited hyperproliferation, increased stemness and epithelial-mesenchymal transition, accompanied by significantly higher aneuploid, homologous recombination deficiency and micro-satellite instable scores, and higher frequencies of cancer driver aberrations. Lower immune scores were observed in DKC1-high tumors as assessed by ESTIMATE algorithm. Tumor Immune Dysfunction and Exclusion (TIDE) analyses revealed robustly higher TIDE scores featured with T Cell exclusion in DKC1-high tumors, and consistently, the diminished trafficking of immune cells into tumor tissues and substantial declines in immune cell infiltration were shown in these tumors. Moreover, DKC1-high tumors exhibited poor response to immune checkpoint inhibitor (ICI)-based immunotherapy. These observations were validated by the findings obtained from other datasets.ConclusionThe present findings unravel genomic alteration- and sex hormone-mediated dysregulation of the telomerase cofactor DKC1 in UCEC tumors, and its upregulation participates actively in the UCEC pathogenesis through tumor-intrinsic and extrinsic mechanisms. DKC1 assessment is useful for patient prognostication and personalized interventions.

ABSTRACT:Previously, we reported that targeting immunoglobulin superfamily member 9 (IGSF9) could enhance antitumor T-cell activity and sensitivity to anti-PD-1 immunotherapy, although the detailed mechanism remains unclear. In this study, we find that, similar to the regulation of PD-L1 expression, interferon gamma (IFN-γ) also induces the expression of IGSF9 in acute myeloid leukemia (AML). The small interfering RNA specifically targeting JAK1 and a STAT1 inhibitor blocking IFN-γ signal pathway significantly inhibit the expression of IGSF9 and PD-L1. As a tumor-specific immune checkpoint molecule, IGSF9 plays a significant role in promoting tumor escape. The induction of both PD-L1 and IGSF9 by IFN-γ in the tumor microenvironment explains why IGSF9 is highly expressed in tumors and tumor-infiltrating immune cells. This induction also underpins the strong synergistic effects when combining anti-IGSF9 and anti-PD-1 therapies. Additionally, IGSF9 also mediates the extramedullary infiltration of AML cells, which can be inhibited by depletion of IGSF9 or anti-IGSF9. The binding epitopes of anti-IGSF9 are located within the immunoglobulin G2 and fibronectin type-III-2 domains of IGSF9. Based on these findings, we develop an antibody-drug conjugate (ADC) targeting IGSF9 (anti-IGSF9-linker-DXd). This ADC exhibits 99.7% purity, and primarily exists in monomeric form, demonstrating excellent homogeneity (drug-to-antibody ratio, 8-10) and specificity. Anti-IGSF9-linker-DXd effectively kills IGSF9-positive tumor cells and exhibits a potent bystander effect. In vivo, anti-IGSF9-linker-DXd almost completely eliminates early- and mid-stage tumors and significantly inhibits the progression of advanced tumors. In summary, our findings underscore the potential of IGSF9 as a novel therapeutic target for AML treatment, highlighting its role in disease progression and the efficacy of targeted therapies.

Lactate dehydrogenase A (LDHA) is highly expressed in various tumors. However, the role of LDHA in the pathogenesis of B-cell lymphoma remains unclear. Analysis of data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases revealed an elevated LDHA expression in diffuse large B-cell lymphoma (DLBC) tissues compared with normal tissues. Similarly, our results demonstrated a significant increase in LDHA expression in tumor tissues from the patients with B-cell lymphoma compared with those with lymphadenitis. To further elucidate potential roles of LDHA in B-cell lymphoma pathogenesis, we silenced LDHA in the Raji cells (a B-cell lymphoma cell line) using shRNA techniques. Silencing LDHA led to reduced mitochondrial membrane integrity, adenosine triphosphate (ATP) production, glycolytic activity, cell viability and invasion. Notably, LDHA knockdown substantially suppressed in vivo growth of Raji cells and extended survival in mice bearing lymphoma (Raji cells). Moreover, proteomic analysis identified feline sarcoma-related protein (FER) as a differential protein positively associated with LDHA expression. Treatment with E260, a FER inhibitor, significantly reduced the metabolism, proliferation and invasion of Raji cells. In summary, our findings highlight that LDHA plays multiple roles in B-cell lymphoma pathogenesis via FER pathways, establishing LDHA/FER may as a potential therapeutic target.

This study investigates the role of Annexin A1 (ANXA1) in regulating T cell function and its implications in bone marrow adiposity in aplastic anaemia (AA). Utilizing single-cell sequencing analysis, we compared bone marrow tissues from AA patients and healthy individuals, focusing on T cell subgroups and their impact on bone marrow pathology. Our findings reveal a significant activation of CD8+ T cells in AA, driven by reduced ANXA1 expression. This heightened T cell activity promotes adipogenesis in bone marrow-derived mesenchymal stem cells via IFN-γ secretion. Overexpression of ANXA1 was found to suppress this process, suggesting its therapeutic potential in AA treatment. The study highlights ANXA1 as a crucial regulator in the AA-associated immune microenvironment and bone marrow adiposity. KEY POINTS: This study found that ANXA1 is significantly downregulated in AA and provides detailed insights into its critical role in the disease. The study demonstrates the excessive activation of CD8+ T cells in the progression of AA. The research shows that the overexpression of ANXA1 can effectively inhibit the activation of CD8+ T cells. The study confirms that overexpression of ANXA1 reduces the secretion of the cytokine IFN-γ, decreases adipogenesis in bone marrow-derived mesenchymal stem cells and may improve AA symptoms. This research provides new molecular targets for the treatment of AA.

Multiple myeloma (MM) is an incurable plasma cell malignancy that has prompted investigations into new potential therapeutic avenues. Epigallocatechin-3-gallate (EGCG), a major component of green tea, confers antioxidant, anti-inflammatory, and anti-tumor properties. Previous studies have shown that EGCG inhibits proliferation and induces apoptosis of multiple myeloma cells, however its underlying molecular mechanisms are largely unknown. In this study, we accordingly sought to examine the therapeutic effects and underlying mechanisms of EGCG on MM.Initially, using CCK8 (Cell Counting Kit-8) assays and Annexin V-FITC/PI staining, we demonstrated that EGCG dose-dependently reduced cell viability and induced apoptosis in the MM cell lines MM.1S and RPMI 8226. Subsequently, mRNA sequencing of EGCG-treated MM.1S cells revealed a significant upregulation of genes associated with endoplasmic reticulum stress (ERS), including P-eIF2α (phosphorylation-eukaryotic translation initiation factor 2 alpha), ATF4 (activating transcription factor 4), CHOP (C/EBP homologous protein, DDIT3), and PUMA (p53 upregulated modulator of apoptosis, BBC3), which were confirmed at the protein level by western blotting. Furthermore, treatment with the eIF2α inhibitor ISRIB reduced the rates of EGCG-induced apoptosis and promoted increases in the protein expression of all four ER stress-related molecules in MM cells. Additionally, mRNA-seq data revealed a downregulation of α-Tubulin 1b (TUBA1B) expression in EGCG-treated MM cells, which was confirmed by western blotting and immunofluorescence analyses. Moreover, we utilized a mouse model to show that EGCG inhibited myeloma tumor growth, which was inhibited by ISRIB.In summary, the findings of this novel study indicated that EGCG promotes apoptosis of MM cells, both via activation of the ER stress pathway and disruption of cytoskeletal integrity. These findings highlight the multi-faceted anti-tumor effects of EGCG and its potential clinical application in MM treatment.

The role of programmed cell death 4 (PDCD4) in multiple myeloma (MM) development remains unknown. Here, we investigated its role and action mechanism in MM. Bioinformatic analysis indicated that patients with MM and high PDCD4 expression had higher overall survival than those with low PDCD4 expression. PDCD4 expression promoted MM cell apoptosis and inhibited their viability in vitro and tumor growth in vivo. RNA-binding protein immunoprecipitation sequencing analysis showed that PDCD4 is bound to the 5' UTR of the apoptosis-related genes PIK3CB, Cathepsin Z (CTSZ), and X-chromosome-linked apoptosis inhibitor (XIAP). PDCD4 knockdown reduced the cell apoptosis rate, which was rescued by adding PIK3CB, CTSZ, or XIAP inhibitors. Dual luciferase reporter assays confirmed the internal ribosome entry site (IRES) activity of the 5' UTRs of PIK3CB and CTSZ. An RNA pull-down assay confirmed binding of the 5' UTR of PIK3CB and CTSZ to PDCD4, identifying the specific binding fragments. PDCD4 is expected to promote MM cell apoptosis by binding to the IRES domain in the 5' UTR of PIK3CB and CTSZ and inhibiting their translation. Our findings suggest that PDCD4 plays an important role in MM development by regulating the expression of PIK3CB, CTSZ, and XIAP, and highlight new potential molecular targets for MM treatment.

The plasma cell malignancy, multiple myeloma (MM), has significantly improved by the application of new drugs and autologous hematopoietic stem cell transplantation. However, MM remains incurable. A number of studies have revealed an anti‐MM effect of natural killer (NK) cells; however, their clinical efficacy is limited. Furthermore, glycogen synthase kinase (GSK)‐3β inhibitors show an antitumor function. In this study, we aimed to evaluate the potential roles of a GSK‐3β inhibitor (TWS119) in the regulation of NK cell cytotoxicity against MM. Our results showed that, in the presence of TWS119, the NK cell line, NK‐92, and in vitro‐expanded primary NK cells exhibited a significantly higher degranulation activity, expression of activating receptors, cellular cytotoxicity, and cytokine secretion when they were exposed to MM cells. Mechanistic studies indicated that TWS119 treatment markedly upregulated RAB27A expression, a key molecule for NK cell degranulation, and induced the colocalization of β‐catenin with NF‐κB in the nucleus of NK cells. More importantly, GSK‐3β inhibition combined with the adoptive transfer of TWS119‐treated NK‐92 cells significantly reduced tumor volume and prolonged the survival time of myeloma‐bearing mice. In summary, our novel findings suggest that targeting GSK‐3β through the activation of β‐catenin/NF‐κB pathway may be an important approach to improve therapeutic efficacy of NK cell transfusion for MM.

Acquired aplastic anemia (AA) is a bone marrow failure (BMF) disease, characterized by fatty bone marrow (BM) and BM hypocellularity resulted from auto-immune dysregulated T cells-mediated destruction of BM haemopoietic stem cells (HPSC). The objective of this study was to investigate potential therapeutic effect of irisin, a molecule involved in adipose tissue transition, on AA mouse model. Our results showed that the concentration of irisin in serum was lower in AA patients than in healthy controls, suggesting a role of irisin in the pathogenesis of AA. In the AA mice, irisin administration prolonged the survival rate, prevented or attenuated peripheral pancytopenia, and preserved HPSC in the BM. Moreover, irisin also markedly reduced BM adipogenesis. In vitro results showed that irisin increased both cell proliferation and colony numbers of HPSC. Furthermore, our results demonstrated that irisin upregulated the expression of mitochondrial ATPase Inhibitory Factor 1 (IF1) in HPSC, inhibited the activation of mitochondrial fission protein (DRP1) and enhanced aerobic glycolysis. Taken together, our findings indicate novel roles of irisin in the pathogenesis of AA, and in the protection of HPSC through stimulation of proliferation and regulation of mitochondria function, which provides a proof-of-concept for the application of irisin in AA therapy.

BACKGROUND:Systematic and comparative studies on CD4+ T-lymphocytes in aplastic anemia (AA), myelodysplastic syndrome (MDS), and acute myelogenous leukemia (AML) are scarce. This study aimed to investigate the importance of CD4+ T-cells in bone marrow (BM) failure.METHODS:The proportions of Th1, Th2, Th17, and Treg cells in peripheral blood mononuclear cells (PBMCs) were examined by flow cytometry (FCM). The mRNA expression levels of transcription factors were measured using real-time PCR.RESULTS:The proportions of Th1, Th17 cells, and Th1/Th2 in the AA group were higher, whereas Th2 and Tregs were lower compared to controls. The proportions of Th17 and Treg cells accompanied by RORγt, and Foxp3 expression were significantly higher in the MDS group. The proportions of Th1, Th17, and Th1/Th2 were higher, whereas Th2 cells and GATA3 expression were significantly lower in MDS-multilineage dysplasia group, than in control group. The proportions of Th1, Th17, and Th1/Th2 were lower in MDS-excess blasts, and AML groups, than in controls, whereas that of Th2 and Treg cells accompanied by GATA3, and Foxp3 expression were significantly higher.CONCLUSIONS:Imbalance in CD4+ T-cell subsets may play a critical role in the pathogenesis and BM failure in the investigated diseases.

Acquired aplastic anemia (AA) is a disease with fatal bone marrow failure (BMF), histopathologically characterized by fatty bone marrow (BM) and T cell-induced destruction of BM-hemopoietic stem cells (HSCs). The objective of this study was to investigate the potential therapeutic effect of irisin, a molecule involved in adipose tissue transition, on T cell-mediated BMF in a mouse model. Our results showed that the concentration of irisin in serum was significantly lower in AA patients than in healthy controls, suggesting a role of irisin in the pathogenesis of AA. In the BMF mice, irisin significantly prolonged the mouse survival rate, prevented severe pancytopenia, preserved HSCs in the BM and ameliorated BM failure. Moreover, irisin also significantly inhibited BM adipogenesis. Treating HSCs with irisin in vitro promoted cell proliferation and increased colony numbers, suggesting a novel regulatory effects of irisin on HSCs proliferation and self-renewal. Moreover, our results demonstrated that irisin upregulated the expression of mitochondrial ATPase Inhibitory Factor 1 (IF1) in HSCs,inhibited the activation of mitochondrial fission protein (DRP1) and enhanced aerobic glycolysis, suggesting a role of the IF1 pathway in the irisin-mediated protection of HSCs. Taken together, irisin protects against destruction of HSCs and BM microenvironment in the BMF pathogenesis, which provides a proof-of-concept for the application of irisin in immune-mediated AA therapy.Funding: The work was supported by National Natural Science Foundation of China Grants (81970743), Rongxiang Regenerative Medicine Foundation of Shandong University (2019SDRX-05), The Key Research and Development Program of Shandong Province (2019JZZY011115), The Joint Research Funds for Shandong University and Karolinska Institute (SDU-KI-2019-15) and The Key Research and Development Program of Shandong Province (2021CXGC011101). Declaration of Interest: The authors have declared that no conflict of interest exists.Ethical Approval: All animal studies were approved by the Ethics Committee of the Second Hospital of Shandong University (Approve number: KYLL-2022LW001).