Min Gao

Pancreatic ductal adenocarcinoma (PDAC) accumulates vast amounts of hyaluronic acid (HA), generating a rigid, high‐pressure stroma that blocks drug delivery and infiltration. Although hyaluronidase (HAase) can dismantle this barrier, systemic administration of HAase depletes HA from healthy tissues and causes dose‐limiting toxicities. Here we exploited the inherent hypoxia‐driven tumor‐homing capacity of Escherichia coli BL21 to create an autonomous, self‐amplifying delivery system (SHEc) that synthesized and secreted the highly active HA‐specific HAase (SHAase) from Streptomyces koganeiensis exclusively within the tumor. Guided by the pelB signal peptide, SHAase could be translocated to the periplasm and released into the extracellular space only where SHEc accumulates. In vitro, SHEc selectively colonized the necrotic core of HA‐rich multicellular tumor spheroids (MCTS) formed by Panc02 cells and TGF‐β‐activated NIH/3T3 cancer‐associated fibroblasts, degrading 44.43% of HA within 24 h. This on‐site HA digestion increased drug penetration depth by 2.92‐fold, decreased hypoxic fraction by 54.81%, and enhanced gemcitabine‐induced apoptosis. Thus, SHEc converts a systemically toxic protein into a tumor‐restricted stromal remodeling agent, offering a safe and potent strategy to enhance chemotherapy against PDAC.

Background: Metabolic reprogramming is a hallmark of acute myeloid leukemia (AML) and provides a rich source of therapeutic vulnerabilities. Among these, de novo pyrimidine biosynthesis has emerged as an important metabolic dependency, yet its contribution to AML progression remains incompletely defined. DHODH, a rate-limiting enzyme in this pathway, represents a promising therapeutic target; however, the clinical development of DHODH inhibitors has been constrained by limited efficacy and dose-limiting toxicity. Thus, defining the mechanistic role of DHODH in AML and developing strategies to improve the therapeutic index of DHODH inhibition remain important unmet needs. Methods: The Cancer Dependency Map (DepMap) database was utilized to identify AML-essential genes that were preferentially required for AML cell survival. Gene set enrichment analysis (GSEA) was used to characterize metabolic dependencies and identify candidate targets. The functional role of DHODH was subsequently evaluated by using genetic knockout in AML cell lines and patient-derived xenograft (PDX) cells. NSGS mice were used in the “human-in-mouse” xenograft mice model. Metabolic profiling coupled with ¹³C isotope tracing was performed to define DHODH-dependent metabolic alterations, while RNA-seq and genetic rescue assays were used to investigate the mechanisms underlying DHODH-mediated leukemogenesis and ferroptosis. Pharmacologically, we evaluated the DHODH inhibitor BRQ and developed an HSA-based BRQ delivery strategy to improve therapeutic efficacy and reduce systemic toxicity. Results: Our study identified DHODH as a critical vulnerability in AML. DHODH knockout (KO) significantly suppressed AML cell growth, induced apoptosis in vitro, and markedly inhibited AML progression in vivo, supporting a crucial role of DHODH in leukemogenesis. Metabolic profiling further confirmed the dependence of AML cells on DHODH-mediated de novo pyrimidine biosynthesis for leukemic progression. RNA-seq revealed marked activation of the ferroptosis pathway following DHODH KO, with HMOX1 identified as a functionally essential target of DHODH depletion-induced ferroptosis. Pharmacologically, the DHODH inhibitor BRQ phenocopied the antileukemia effects of genetic DHODH depletion both in vitro and in vivo. Of note, we have developed an HSA-based delivery strategy aimed at improving therapeutic efficacy while reducing systemic toxicity. Targeting DHODH, particularly with HSA-conjugated BRQ, represents a promising therapeutic strategy for AML.

Rheumatoid arthritis (RA) is an autoimmune disorder marked by chronic joint inflammation and tissue damage. While current systemic therapies mainly reduce inflammation, they often lack regenerative capacity and cause off-target effects. To address this, we developed an injectable collagen-hyaluronic acid (Col-HA-NHS) hydrogel for intra-articular delivery of umbilical mesenchymal stem cell (UMSC) spheroids. The hydrogel demonstrated excellent shear-thinning and regelable properties, biocompatibility, and controlled degradation. Encapsulated UMSC spheroids (S-UMSCs) exhibited enhanced paracrine function, secreting higher levels of growth factors such as epidermal growth factor (EGF) and fibroblast growth factor (FGF) than those of monolayer cultures. In vitro, the hydrogel-spheroid system (CH/S-UMSCs) significantly inhibited M1 macrophage polarization, as indicated by reduced CD86 expression, and decreased intracellular reactive oxygen species (ROS). In a rat collagen-induced arthritis (CIA) model, intra-articular administration of CH/S-UMSCs led to the most pronounced reduction in paw swelling and the highest clinical healing score among all groups. Histopathological and micro-CT analyses further revealed that this treatment markedly alleviated synovial inflammation, mitigated cartilage erosion, and suppressed bone destruction, while significantly improving bone mineral density (BMD) and trabecular microstructure. This combinatory strategy thus provides a synergistic therapy integrating immunomodulation and tissue regeneration, offering a promising localized treatment for RA.

Liver fibrosis represents a critical intermediate stage in the progression of chronic liver diseases toward cirrhosis. Conventional therapeutic strategies remain limited by insufficient efficacy, notable side effects, or narrow applicability, making the effective reversal of fibrosis a persistent clinical challenge. Although gene silencing technologies offer a promising therapeutic avenue, their clinical translation is hampered by poor delivery efficiency, instability in vivo, and lack of tissue specificity. To address these issues, we developed a lactobionic acid‑modified aminated glycogen (Lac‑AGly) nanoparticle system for the targeted delivery of connective tissue growth factor (CTGF) targeting siRNA. By utilizing natural glycogen as a biodegradable backbone, a degree of amination of 51.2% conferred efficient siRNA binding capacity, while lactobionic acid modification enabled selective recognition of hepatocyte-expressed asialoglycoprotein receptors (ASGPR). The resulting Lac-AGly/siCTGF nanocomplexes exhibited a uniform spherical morphology with an average particle size of 247.2 ± 8.8 nm and a zeta potential of 28.5 ± 3.8 mV. In vivo studies demonstrated that Lac-AGly/siCTGF significantly attenuated liver fibrosis, evidenced by a reduction in the collagen-positive area from 14.3% to 3.1%. Collectively, the Lac‑AGly/siCTGF nanoparticle system integrated biocompatibility, serum stability, and active hepatic targeting into a single platform, significantly improving siRNA delivery efficiency and gene‑silencing efficacy while maintaining favorable biosafety. This work provided a novel and translatable strategy for precise molecular intervention in liver fibrosis.

T lymphocyte therapies demonstrate significant promise in the treatment of cancer and infectious diseases. An efficient gene delivery system is essential for the safe and reliable introduction of exogenous genes, especially mRNA, into cells to achieve therapeutic purposes. Commercial transfection reagents are suitable for the transduction of plasmids to adherent cells, whereas they are ineffective for suspension cells such as T lymphocytes and for unstable mRNA. Moreover, the cytotoxicity of transfection reagents themselves constitutes an impediment to their application. The challenge of mRNA transduction to T lymphocytes with high efficiency is notably formidable. An innovative transfection strategy is urgently needed. In this study, we synthesized aminated glycogen (AGly) nanoparticles as gene vectors, encapsulating mRNA to facilitate the efficient transfection of T lymphocytes. Compared to commercial transfection reagent polyethylenimine (PEI), the AGly demonstrated favorable biocompatibility. The positive charge provided AGly with pH buffering ability and mRNA-binding capacity. AGly formed stable nanoparticles with mRNA, which were readily internalized by suspension cells and enhanced the cellular uptake of mRNA. In the T lymphocyte model cell lines (Jurkat cells and HuT 78 cells), AGly demonstrated superior transfection efficiency than that of PEI. Consequently, AGly can emerge as a viable mRNA vector for the efficient transfection of T lymphocytes whilst circumventing the issue of cytotoxicity. The AGly designed in this study provides a novel concept for the exploitation of transfection reagents and proposes a promising methodology for the proficient transfection of T lymphocytes which may significantly contribute to the treatment of cancer and other complex diseases.