Journal of Biomedical Science最新文献

Pyruvate kinase M2 (PKM2) is a key enzyme involved in glycolysis, yet its role in cancer extends far beyond metabolic flux. Unlike its isoform PKM1, PKM2 exhibits unique regulatory properties due to alternative splicing and dynamic structural plasticity, enabling it to translocate into the nucleus. Once nuclear, PKM2 functions as a signal receiver, gene programmer, and metabolic modulator by acting as a co-transcriptional activator and protein kinase. In this capacity, nPKM2 (nuclear PKM2) orchestrates the transcription of genes involved in glycolysis, lipogenesis, redox homeostasis, and cell cycle progression, thereby reinforcing the Warburg effect and promoting tumor growth, metastasis, and resistance to stress. In this regard, nPKM2 can be considered as the oncogenic component of PKM2. This review consolidates current knowledge on the structural basis of PKM2 assembly and the post-translational modifications that govern its oligomeric state and nuclear import. We also explore emerging therapeutic strategies aimed at targeting nPKM2, including small-molecule modulators that stabilize its cytosolic tetrameric form or disrupt its nuclear functions. Ultimately, the multifaceted roles of nuclear PKM2 underscore its significance as a critical oncoprotein and a promising target for precision cancer therapy.

Background: CD24 plays a crucial role not only in promoting tumor progression and metastasis but also in modulating macrophage-mediated anti-tumor immunity. However, its impact on the immune landscape of the tumor microenvironment (TME) remains unexplored. Here, we investigated the role of CD24a, the murine CD24 gene, in tumor progression and TME immune dynamics in a murine triple-negative breast cancer (TNBC) model.

Methods: Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 knockout technology was employed to generate CD24a knockout in the murine TNBC cell line 4T1. Flow cytometry was utilized to analyze the immune cell populations, including myeloid-derived suppressor cells (MDSCs), natural killer cells, T cells, and macrophages, within tumors, spleens, and bone marrow in the orthotopic mouse 4T1 breast cancer model. Immunofluorescence (IF) staining was used to detect the immune cells in tumor sections. High-speed confocal was used to perform three-dimensional (3D) mapping of immune cells in the 4T1 orthotopic tumors.

Results: Knocking out CD24a significantly reduced tumor growth kinetics and prolonged mouse survival in vivo. Flow cytometry and IF analysis of tumor samples revealed that CD24a loss significantly promoted the infiltration of M1 macrophages and cytotoxic CD8⁺ T cells into the TME while reducing the recruitment and expansion of granulocytic MDSCs (gMDSCs). In vitro coculture experiments showed that CD24a deficiency significantly enhanced macrophage-mediated phagocytosis and CD8⁺ T cell-mediated cytotoxicity, effects that were partially reversed by re-expression of CD24a. Moreover, in vivo depletion of macrophages and CD8⁺ T cells reverted the delayed tumor growth caused by CD24a knockout, underscoring their critical role in tumor growth suppression associated with CD24a knockout. 3D mapping of immune cells in the TME confirmed the anti-tumor immune landscape in the CD24a knockout 4T1 tumors. Furthermore, in vitro analysis showed that CD24a loss upregulated macrophage colony-stimulating factor expression while suppressed levels of CXCL1, CXCL5, and CXCL10, chemokines known to recruit gMDSCs, further providing a molecular basis for enhanced macrophage recruitment and diminished gMDSC accumulation.

Conclusions: Our findings suggest that CD24a may regulate immune suppression within the TNBC TME. Targeting CD24a enhances macrophage- and CD8⁺ T cell-mediated anti-tumor immune responses and is associated with a shift in the TME toward a more immunogenic state, thereby suppressing tumor growth. These results may support CD24 as a promising immunotherapeutic target for TNBC.

Background: Taiwan has the highest prevalence of chronic kidney disease (CKD) and end-stage kidney disease (ESKD) globally, making them major public health concerns with significant morbidity, mortality, and healthcare burden. While genetic risk factors for kidney disease have been identified in previous studies, the contribution of rare genetic variants remains unclear.

Methods: This study utilized whole-exome sequencing (WES) to investigate the role of missense rare variants in CKD and ESKD susceptibility. Genomic data from 500 Taiwanese individuals at Taipei Medical University Hospital were included based on strict clinical diagnostic criteria, comprising 200 CKD cases, 200 ESKD cases, and 100 healthy controls. Independent validation was performed using ESKD Asian cohorts from the All of Us Research Program (AoU) (N = 222) and the Tohoku Medical Megabank Organization (ToMMo) (N = 140).

Results: We identified rare pathogenic variants in known monogenic kidney disease genes, including PKD1 and COL4A4, confirming their role in disease susceptibility. We replicated GWAS-reported genes such as SPI1, RIN3, FTO, SIPA1L3, and EEF1E1, highlighting their contribution through both common and rare variants. Beyond previously reported genes, we identified novel rare pathogenic variants in PEX1, GANAB, DYNC2H1, and PROKR2. Pathway enrichment analysis suggested that ciliopathies, inflammation, and metabolic dysfunction may contribute to kidney disease progression. Furthermore, the polygenic score (PGS) for ESKD demonstrated strong predictive utility for kidney function, with high genetic risk having a greater influence than comorbidities such as diabetes and overweight. The prediction power of ESKD PGS was further confirmed in the AoU Asian population.

Conclusions: This study provides novel insights into the genetic architecture of CKD and ESKD in the Taiwanese population, utilizing a hospital-based cohort with strict clinical diagnostic criteria to ensure precise phenotype classification. We propose that individuals with high genetic risk may benefit from earlier interventions, while those with lower PGS may be better managed through lifestyle modifications targeting comorbidities. The findings highlight the importance of preventive strategies and precision medicine in kidney disease management.

Glucose metabolism is a pivotal hub for cellular energy production and the generation of building blocks that support cell growth, survival, and differentiation. Cancer cells undergo metabolic reprogramming to sustain rapid proliferation, survive in harsh microenvironments, and resist therapies. Beyond producing energy and building blocks to meet cancer cell demands, glucose metabolism generates numerous metabolites that serve as signaling molecules, orchestrating signaling pathways and epigenetic modifications that regulate cancer cell phenotypes and immunity. In this review, we discuss how glucose, through its metabolism and direct actions, influences diverse biological processes driving cancer progression and therapeutic resistance, while also exploring metabolic vulnerabilities in cancer for therapeutic strategies.

Background: Immunomodulatory agents benefit a small percentage of patients with oral cancer (OC), a subset of head and neck cancer. Cathepsin S (CTSS), a lysosomal protease, has been frequently associated with tumor immunity. This study aimed to investigate the mechanism by which tumor CTSS affects anti-tumor immunity through the regulation of interleukin-7 (IL-7) to overcome this obstacle.

Methods: OC patients' samples were used to disclose the correlation among CTSS and CD8⁺ T cell infiltration levels. The cytokine array was used to investigate the effect of CTSS on the secretion of cytokine/chemokines. We utilized various cell biology experiments to investigate the molecular mechanism of CTSS that mediates IL-7 secretion in OC cell lines, including fluorescence resonance energy transfer, immunogold-labeled transmission electron microscopy, IL-7-enzyme-linked immunosorbent assay, immunofluorescence staining, and pull-down assay. Two syngeneic OC mice models were utilized to investigate the anti-cancer effects and the tumor immunity modulation effects of RJW-58, a CTSS activity inhibitor, and the combination with the anti-PD-1 antibody.

Results: CTSS expression was inversely correlated with CD8⁺ T-cell infiltration in clinical samples. In vivo and in vitro studies using a mouse OC tumor model showed that CTSS-knockdown inhibited tumor growth and enhanced CD8⁺ T cell proliferation. These results were counteracted by co-treatment with anti-CD8 or anti-IL-7 antibodies. CTSS inhibition also remodeled the memory CD8⁺ T cell subsets within tumor tissues in vivo. Mechanistically, CTSS inhibited IL-7 secretion by disrupting its intracellular transport route. This was achieved by recognizing the intracellular domain of the IL-7 receptor (IL-7R), which bound IL-7 in granular vesicles. RJW-58 enhanced IL-7 secretion and exerted an anti-tumor effect. RJW-58 enhanced the therapeutic effect of the anti-PD-1 antibody in syngeneic mouse models.

Conclusion: The findings indicate that CTSS negatively regulates IL-7 secretion by interacting with IL-7R. The CTSS-targeting strategy has the potential to reinvigorate IL-7-directed anti-tumor T cell immunity and enhance the therapeutic effect of the anti-PD-1 antibody.

The application of smart hydrogels has become a booming research frontier in biomedical engineering. With the development of intelligent drug delivery systems, various biomimetic and biodegradable hydrogels are employed for localized drug delivery to tissues in the preclinical applications. These advanced materials are designed to match the diverse environmental and functional requirements of various tissue types and organs. This article discusses the attractive characteristics of smart hydrogels as delivery systems and reviews the design of a range of smart hydrogels, as well as the challenges of tissue-specific drug delivery, focusing on the last 5 years of frontward research.

Background: The organic cation transporter 3 (OCT3) is a ubiquitous transporter that carries both endogenous and exogenous substrates, such as histamine and cisplatin. Our investigations have shown that OCT3 directly interacts with the tetraspanin CD63. CD63 is a marker for activated basophils and mast cells, which are granulocytes capable of rapidly releasing large amounts of histamine. This makes them key players in the development of allergic reactions.

Methods and results: In this work, we demonstrated that OCT3 is present in murine and human basophils and is strongly colocalized with CD63 in a specific region of the plasma membrane, particularly after cell activation leading to histamine release. Furthermore, we confirmed that part of the histamine release from basophils is mediated by OCT3. In a mouse model of contact dermatitis, the presence of OCT3 is crucial for determining the severity of the allergic reaction. The presence of CD63 also seems to be important for regulating the allergic response, although it does not directly affect histamine secretion. RNA-Seq and metabolome analyses revealed that wild-type mice and mice with genetic deletion of OCT3 (OCT3^-/-) are phenotypically very similar, and that the observed effects in OCT3^-/- organisms can be attributed mainly to the genetic deletion of the OCT3 transporter.

Conclusions: In conclusion, OCT3 is a transporter for histamine in granulocytes, which plays a crucial role in determining the intensity of allergic reactions and may be a target for interventions aimed at reducing their severity.

Background: Clinical research has identified stomach dysmotility as a common feature of obesity. However, the specific mechanisms driving gastric emptying dysfunction in patients with obesity remain largely unknown. In this study, we investigated potential mechanisms by focusing on the homeostasis of gastric smooth muscle.

Methods: An obese mouse model was established using a high-fat diet (HFD). Immunofluorescence analysis and Western blotting were employed to assess smooth muscle status using stage-specific markers. An in vitro culture model of differentiated human gastric smooth muscle cells (SMCs) was treated with lipids, siRNA-peptide-based nanoparticles and pharmaceutical compounds. Global lipidomic and RNA sequencing analyses were performed. The findings were evaluated in patients with obesity, using gastric samples from individuals who underwent sleeve gastrectomy, to evaluate their clinical relevance.

Results: The smooth muscle layers in gastric tissue from both mice fed on a HFD as well as patients with obesity exhibited altered differentiation status. Treatment of differentiated human gastric SMCs with lipids phenocopies these alterations and is associated with increased expression of PDK4 and ANGPTL4. Inhibition of PDK4 or ANGPTL4 upregulation prevents these lipid-induced modifications. PPARD activation stimulates PDK4 and ANGPTL4 upregulation, leading to SMC dedifferentiation. Notably, PDK4 and ANGPTL4 levels correlate with immaturity and alteration of gastric smooth muscle in patients with obesity.

Conclusions: Obesity triggers a phenotypic change in gastric SMCs, driven by the activation of the PPARD/PDK4/ANGPTL4 pathway. These mechanistic insights offer potential biomarkers for diagnosing stomach dysmotility in patients with obesity.

Background: Adenosine is a ubiquitous endogenous molecule capable of influencing several pathophysiological aspects. The adenosine system is extremely complex, starting from the generation of intracellular and extracellular adenosine, the regulation of its levels, and its action on four different receptors that vary in affinity and distribution in the different cell types and tissues. The most relevant effects of adenosine during infections and inflammation are documented on all types of immune cells, including those of adaptive immunity (T lymphocytes, B lymphocytes, regulatory cells) and of natural immunity (macrophages, polymorphonuclear cells, dendritic cells, natural killer). Of interest, the adenosine system is also strongly involved in the pathophysiology of colonic cells. Clostridioides difficile (C. difficile), responsible for 15-20% of all cases of antibiotic-associated diarrhea, is an infection that has been evolving over the past two decades due to the unstoppable spread of C. difficile in the anthropized environment and the progressive human colonization. The pathological activity of C. difficile is due to toxin A (TcdA) and B (TcdB) which profoundly alter the homeostasis of the adenosine system, acting both at the level of its generation and on the expression and regulation of adenosine receptors. The final effect consists in an attenuation of the inflammatory response to favor the persistence of the C. difficile infection.

Conclusion: This review highlights a new ability of C. difficile, through its Tcds, of manipulating the host to its advantage.