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Huntington’s disease (HD) is the best-known example of a neurodegenerative disorder caused by the expansion of a glutamine-encoding CAG repeat in the causative gene. Growing evidence indicates that somatic CAG expansions play a key role in disease progression, providing a strong rationale for therapeutic strategies directly targeting the repeat tract. However, achieving sufficient efficacy while maintaining allele selectivity and minimizing off-target effects remains a major challenge. Here, we developed allele-selective, CAG-targeting artificial microRNA (amiRNA) molecules that exhibit significantly reduced off-target risk. This was achieved by introducing specific substitutions at selected positions within the guide strand. These molecules effectively downregulated polyglutamine (polyQ) proteins in cellular models of HD, spinocerebellar ataxias types 1 and 3, and dentatorubral pallidoluysian atrophy. The most promising candidate, amiR136-13A, reduced mutant huntingtin levels in different brain regions of the HD mouse model and did not induce toxicity up to 28 weeks following a single administration of an AAV5 vector. Transcriptomic profiling of human HD neural stem cells treated with amiR136-13A revealed minor changes in gene expression. Moreover, amiR136-13A reduced the level of HTT1a, a short pathogenic isoform of huntingtin. Collectively, these findings identify amiR136-13A as a potent, selective, and safe therapeutic candidate for HD and potentially other polyQ disorders.

Widespread uses of nuclear materials increase the risk of accidental or intentional radiation exposure, which can result in acute radiation syndrome (ARS). Hematopoietic ARS (H-ARS) occurs at relatively low doses and is potentially lethal without intervention. While several FDA-approved cytokine-based radiomitigators exist, many require repeated dosing, complicating deployment in mass-casualty scenarios. This study evaluated a novel long-acting, murine-reactive granulocyte–macrophage colony-stimulating factor (LA-GM-CSF; mPDM608) as a prophylactic and mitigative countermeasure for H-ARS. Male and female C57BL/6 mice were exposed to lethal or sublethal total body irradiation (TBI) and treated with LA-GM-CSF using single- or multi-dose regimens administered before or after TBI. Safety, 30-day survival, hematologic recovery, bone marrow cellularity, serum GM-CSF pharmacokinetics, endothelial injury markers, and cytokine profiles were assessed using standard hematology, histopathology, ELISA, and multiplex assays. LA-GM-CSF was well tolerated at doses up to 30 mg/kg. Single or limited dosing conferred significant survival benefits compared with vehicle controls, with optimal efficacy observed at lower doses (3 mg/kg). Post-TBI administration as a single dose 24 h after exposure markedly improved survival in both sexes, with stronger hematopoietic recovery in males. LA-GM-CSF accelerated recovery of neutrophils, red blood cells, platelets, hematocrit, and sternal megakaryocytes, prolonged circulating GM-CSF levels, and favorably modulated endothelial injury markers and select cytokines. LA-GM-CSF demonstrates strong potential as a next-generation radiation countermeasure, providing robust survival benefit and hematopoietic recovery with minimal dosing. The results shown here support further development for H-ARS management under the FDA Animal Rule.

Mesenchymal stromal cells (MSCs) have shown immunomodulatory effects and great promise in many inflammatory diseases such as acute respiratory distress syndrome (ARDS). However, several barriers to translation remain such as cell availability and potency. This study evaluates the therapeutic potentials of three types of MSCs, bone marrow-derived MSCs (BM-MSC), the human induced pluripotent stem cell-derived MSC wild type (iMSC WT) and β2 microglobulin-knockout iMSCs (iMSC B2M KO) with or without proinflammatory cytokine preconditioning. BM-MSC, iMSC WT and iMSC B2M KO were preconditioned with a proinflammatory cytokine cocktail (Cytomix: IL-1β, IFN-γ and TNF-α). Immunoregulatory biomarkers were analysed by flow cytometry and cytokines released by ELISA. MSC antimicrobial properties were analysed via CFU assays while the MSCs’ immunomodulatory effects were evaluated using macrophage activation and T cell proliferation assays. Proinflammatory cytokine preconditioning enhanced the therapeutic potency of all three types of MSCs by increasing immunomodulatory marker expression, enhancing the antimicrobial effects and improving MSC-mediated inhibition of T cell proliferation. These findings provided new insights into the therapeutic potencies of MSCs in inflammation. Further studies are required for in vitro characterisation of the MSCs and in vivo efficacy verification of these MSCs prior to their clinical application.

Background/Objectives: Overexpression of transferrin receptor (TFR1) is common in cancer and may be associated with inferior treatment outcomes. Due to these patterns and TFR1’s essential role in iron metabolism, the protein has been targeted for cytotoxic drug delivery. More recently, increased TFR1 expression has been linked to tumor microenvironment (TME) infiltration by immune effectors in selected tumors, but a comprehensive assessment of the genomic landscape associated TFRC (the gene encoding TFR1) expression has not been conducted. Methods: By utilizing a pan-cancer database of 93,248 patients with whole-exome and whole-transcriptome sequencing, we assessed TFRC-associated multiomic patterns. Results: We found that high TFRC expression correlates with significantly worse overall survival in multiple common solid tumor types, a higher tumor mutational burden (TMB), an increase in infiltrating effector cells with upregulated immune checkpoint markers within the TME, and increased frequency of specific high-risk genomic alterations. Further assessment in cell line models revealed increased susceptibility to cytotoxic T cells when iron metabolism is elevated, despite upregulation of the checkpoint ligand PD-L1. Conclusions: High TFRC expression, therefore, indicates worse clinical risk across multiple common tumor types but potentially increased susceptibility to cytotoxic immune effectors, informing the development of TFR1 biomarker-driven therapeutic strategies.

Background: Acute erythroid leukemia (AEL) or AML-M6 predominantly affects older adults and is rare in childhood. Compared with other AML subtypes, AEL remains relatively understudied because of its rarity. We established LS-CHM, a novel AEL cell line derived from the ascitic fluid of a patient with congenital leukemia. Interestingly, leukemic cells persisted in the ascitic fluid even after successful eradication from the bone marrow and extramedullary sites. Method: Leukemia cells from the ascites fluid exhibited robust proliferation in culture independent of cytokine requirement and were further characterized by flow cytometric immunophenotyping, cytogenetics, cell cycle and doubling time analysis, colony formation, genome and RNA sequencing, myeloid gene next generation sequencing, and cytotoxicity analysis. Results: LS-CHM displayed CD36, partial CD235a, CD31, CD43, and CD71 expression and demonstrated in vitro robust growth and high sensitivity to chemotherapeutic agents. A PDX mouse model showed development of leukemia. Genomic analysis revealed a frameshift BCOR mutation in the absence of additional mutations and downregulated TP53 expression with an exonic non-deleterious mutation. RNA sequencing of LS-CHM cells revealed upregulation of two cohesin complex genes, RAD21 and SMC3, whose high levels are associated with hematopoietic stem cell differentiation into erythroid lineage. Conclusions: LS-CHM represents the first congenital AEL-derived cell line, in contrast to the predominantly adult-origin and often secondary erythroid leukemia cell lines available currently. Thus, LS-CHM provides a unique pediatric and extramedullary AEL model, expanding the existing spectrum of AEL cell lines and offering valuable opportunities for biologic and therapeutic investigations.

Dpep is a cell-penetrating peptide that targets transcription factors ATF5, CEBPB and CEBPD to selectively suppress growth and survival of diverse tumor cell types in vitro and in vivo. Due to these actions and its apparent safety, the peptide has potential as a cancer therapeutic. How Dpep might be combined with other anti-cancer agents to achieve synergistic efficacy and to overcome possible peptide resistance has not been assessed in depth. Based on prior work indicating that Dpep promotes apoptotic cancer cell death and up-regulates multiple pro-apoptotic and tumor suppressor genes, we studied combinations of Dpep with ABT-263, a pro-apoptotic BCL2 family inhibitor, and decitabine, a hypomethylating drug. Combining Dpep with each agent alone or together synergistically suppressed the growth of a range of solid and liquid tumor cell types. Moreover, the combinations synergistically inhibited the growth of cells lines that were selected either in vivo or in vitro for Dpep resistance. Finally, we tested the combination of Dpep with ABT-263 in a mouse melanoma xenograft model. The combination more effectively inhibited tumor growth than either agent alone and, in contrast to vehicle or ABT-263, produced a 40% durable survival rate. Taken together, these observations highlight potential drug partners for the therapeutic development of Dpep.