Journal of Biomedical Science最新文献

Background: The complement receptor immunoglobulin (CRIg), a key microbial pathogen phagocytosis-promoting receptor, responsible for intravascular clearance of bacteria, is purported to be expressed selectively on tissue-fixed macrophages such as Kupffer cells. However, recently it has been reported that neutrophils can also express functional CRIg following activation by inflammatory mediators. Monocytes have been reported not to express CRIg under non-activated conditions. Thus, investigations were undertaken to examine whether blood monocytes express CRIg under cell activation conditions and its role in anti-microbial immunity.

Methods: Monocytes CRIg expression in whole human and mouse blood or peripheral blood mononuclear cells and purified monocytes using density gradient centrifugation or an affinity purification kit was examined using PE/FITC-labelled anti-CRIg monoclonal antibody and flow cytometry. Characterization of CRIg isoforms in monocytes was determined by the detection of CRIg mRNA transcripts and protein using RT-PCR and Western blot, respectively. Gene-edited CRIg^- and CD18^- monocytic THP-1 cell lines were generated to assess the role of CRIg and CD18 in cell adhesion, phagocytosis, and microbial killing. Functional assays were performed using Staphylococcus aureus as a model pathogen.

Results: CRIg was constitutively expressed, dynamically, on the surface of human and mouse blood monocytes. All three human monocyte subpopulations expressed CRIg, equally. The inability to demonstrate expression on monocytes cell surface by previous studies can be explained by its lability during blood storage and loss during monocyte isolation steps. Interestingly of the monocyte subpopulations only the classical and intermediate but not the non-classical showed a loss of CRIg expression. The data showed that loss from the surface was most likely due to relocation of the receptor intracellularly. Monocytes expressed 6 different CRIg mRNA transcripts and immunoreactive isoforms. Using CRIg^- and CD18^- THP-1 monocytic cells, we found that both CRIg and CD18 (CR3/CR4) were critical for cell adhesion, but for phagocytosis and killing of S. aureus, either receptor was independently effective.

Conclusion: The data provide compelling evidence that monocytes express functional CRIg, relevant to the cells' anti-microbial role of the 'wandering' phagocyte and consolidate a view that CRIg is widely expressed in our phagocytic cell system, similar to the classical complement receptors CR3 and CR4.

Background: Infertility affects one in six individuals worldwide despite the advancement of assisted reproductive technologies. Successful embryo implantation is the first step of pregnancy, which relies on the establishment of a receptive uterine microenvironment. However, the mechanisms governing uterine receptivity and implantation failure remain incompletely characterized. Primary cilia serve as key cellular signaling hubs, yet their contribution to human decidualization and uterine receptivity remains largely unexplored.

Methods: Primary cultured human endometrial stromal cells (ESCs) were used to investigate the mechanisms of decidualization, functions of primary cilia, and effects of transforming growth factor-β (TGF-β) in inhibiting prostaglandin E₂ (PGE₂)-induced decidualization. Human endometrial tissues (n = 108) were used to evaluate the clinicopathological parameters. The percentage of ciliated cells and cilia length were determined by immunofluorescent staining and AI-assisted quantification. Pseudopregnancy and pregnancy mouse models were employed to assess the effects of TGF-β1 on uterine receptivity and implantation outcomes.

Results: Prostaglandin E₂, through binding to the EP4 receptor located at the primary cilium, stimulates ESC decidualization, which is augmented by 17β-estradiol and progesterone. Loss of ciliogenesis by genetic or pharmacological inhibition impairs decidualization. Proinflammatory cytokines such as TGF-β inhibit ciliogenesis and thus markedly attenuate PGE₂-mediated decidualization. Mechanistically, TGF-β1 suppressed chicken ovalbumin upstream promoter transcription factor II and its downstream effector kinesin family member 3B, thereby inhibiting ciliogenesis and PGE₂-EP4 signaling. In mice, intrauterine administration of TGF-β1 impaired implantation, while TGF-β receptor blockade restored ciliogenesis, decidualization, and fertility. In women with endometriosis, ESCs displayed shortened cilia and reduced decidual response, which are due to elevated uterine and peritoneal TGF-β1-mediated suppression of ciliogenesis. Finally, women who failed to conceive after in vitro fertilization-embryo transfer (IVF-ET) have shorter and fewer primary cilia in ESCs. Receiver operating characteristic curve analysis demonstrated that both cilia length (AUC = 0.86) and ciliation frequency (AUC = 0.79) can serve as biomarkers for endometrial receptivity, providing predictive value for reproductive outcomes independent of ovarian reserve.

Conclusions: Endometrial primary cilia are indispensable for decidualization and are potential biomarkers for predicting endometrial receptivity. Targeting TGF-β signaling to restore ciliated cell number and ciliary length may serve as a potential therapeutic strategy to improve fertility outcomes.

Background: The therapeutic efficacy of traditional chemotherapy on pancreatic ductal adenocarcinoma (PDAC) remains dismal. In this study, we investigated the efficacy of adding cisplatin to the standard first-line gemcitabine plus nab-paclitaxel (AG) regimen (referred to as AGP) for PDAC treatment, and elucidated the underlying mechanisms, particularly the role of the cGAS-STING pathway in mediating chemotherapy-induced antitumor immunity in PDAC.

Methods: We first reported the therapeutic efficacy of an AGP regimen in patients with PDAC through a clinical retrospective analysis. Next, we mimicked the enhanced efficacy of the AGP regimen in both subcutaneous and orthotopic PDAC mouse models. Comprehensive immune profiling was performed using mass cytometry, flow cytometry, multiplex immunofluorescence, and RNA sequencing to characterize changes in immune cell populations and phenotypes. The functional significance of the cGAS-STING pathway was investigated through genetic ablation of tumor cells and macrophages. Tumor-macrophage interactions were further explored via co-culture assays. Clinical relevance was assessed through a retrospective analysis of cohorts of patients with PDAC and immunohistochemical evaluation of STING expression in tumor tissues.

Results: The AGP regimen confers promising potential to AG regimen in patients with PDAC as well as in PDAC mouse models. Mechanistically, cisplatin-induced DNA damage in tumor cells activated the tumor-intrinsic cGAS-STING pathway, which facilitated the recruitment and activation of CD8⁺ T cells. Furthermore, phagocytosis of tumor-derived damage-associated molecular patterns by tumor-associated macrophages (TAMs) triggered the activation of cGAS-STING signaling and promoted M1 polarization of TAMs without obvious macrophage cell death. Such "STING signaling relay" between tumor cells and TAMs reprogrammed the tumor microenvironment and facilitated chemotherapy efficacy. Clinically, high STING expression in PDAC tissues was associated with increased infiltration of cytotoxic T cells and M1-like macrophages, and was identified as an independent predictor of improved patient prognosis.

Conclusions: This study reports AGP regimen as a promising therapeutic modality for PDAC, and provides a detailed mechanism by which a STING-mediated signaling relay from PDAC tumor cells to TAMs boost antitumor immunity and contribute to AGP chemotherapy efficacy. Furthermore, STING expression in tumor tissues correlated with improved prognosis, highlighting its potential as a predictive biomarker and promising therapeutic target.

Background: Biofilms formed by multidrug-resistant (MDR) Klebsiella spp. present a significant clinical challenge due to elevated antibiotic tolerance. Bacteriophages (phages) represent a promising alternative, particularly in combination with antibiotics, where phage-antibiotic synergy (PAS) can increase antibiofilm activity. Evaluating treatment efficacy in these complex structures requires real-time, noninvasive viability analysis.

Methods: To address this, we used light-sheet fluorescence microscopy (LSFM), a high-resolution, minimally invasive approach, for dynamic tracking of PAS in intact biofilms. To our knowledge, this is the first in vitro application of LSFM for investigating PAS. We studied the combined activity of a virulent phage (vB_KpUKJ_2) and ceftazidime (CAZ) against an extended-spectrum β-lactamase-producing Klebsiella quasipneumoniae.

Results: In planktonic cultures, PAS was strongly affected in a dose-dependent manner. In mature biofilms, LSFM imaging revealed that high-dose phages (10⁸ PFU/mL) combined with CAZ at a 0.25 × minimum inhibitory concentration (MIC) induced a rapid and sustained reduction in viability over 24 h. This regimen significantly outperformed mono-treatments (p < 0.01), demonstrating that phage coadministration can reduce the required antibiotic dose. Mechanistically, treatment resulted in phage-mediated degradation of α- and β-polysaccharides within the extracellular polymeric substance (EPS). Crucially, while phage mono-treatment led to the emergence of resistant mutants, the combination treatment fully suppressed resistance. Whole-genome sequencing revealed mutations in genes such as fhuA, purA, and rpoC, suggesting diverse resistance mechanisms linked to fitness trade-offs such as impaired biofilm formation.

Conclusions: Our findings highlight a precision-guided strategy with translational potential for device-associated infections, providing a mechanistic and methodological foundation for optimizing PAS-based therapies.

Once thought to be solely involved in vasculogenesis, tyrosine kinase with immunoglobulin-like and EGF-like domains 2 (TIE2) has emerged as a crucial marker of progenitor-like cells in the avascular nucleus pulposus (NP), a tissue with notoriously limited regenerative capacity. Recent evidence suggests that TIE2 + NP cells play a pivotal role in disc tissue homeostasis, influencing extracellular matrix maintenance, cellular renewal, and tissue integrity. However, despite the reported regenerative potential of TIE2 + NP cells, their precise function remains enigmatic. This review consolidates in vivo, in vitro, and transcriptomic studies to validate the presence of TIE2 in the NP as a progenitor cell marker. We unravel the complexity of TIE2 + NP cells across species, highlighting key regulatory mechanisms and interspecies variations (including mice, rats, dogs, cows, sheep, pigs, and humans) that may influence their relevance as clinical- and regenerative therapeutic targets. Yet, methodological inconsistencies across studies continue to obscure our understanding of the precise role of TIE2 in NP cell biology. At present, clinical care is limited to managing pain conservatively or resorting to spinal surgery in severe cases. Thus, there exists an urgent need for innovative regenerative strategies to combat disc degeneration and its associated pain and disability. A range of emerging approaches, including biomaterials, gene therapy, and cell-based therapeutics, are under investigation. Within this context, TIE2 + NP cells are of particular interest as potential therapeutic vectors: as for example candidate cells for transplantation, as populations to be stimulated by biologic interventions, or as building blocks in tissue engineering strategies. As progenitor-like cells, they hold the theoretical potential to provide a sustained source of functional NP cells for disc maintenance and repair. By identifying existing knowledge gaps and proposing future research directions, this review aims to clarify their role and accelerate progress toward unlocking their full therapeutic potential.

The key small molecule-based modalities for inducing targeted protein degradation have seen explosive growth over the past decade. They include heterobifunctional degraders such as PROteolysis TArgeting Chimeras (PROTACs): molecules working as protein degraders by inducing proximity between a protein of interest, mostly a disease-causing protein, and an ubiquitin E3 ligase to trigger protein ubiquitination and degradation. The power of PROTACs has been broadly demonstrated, and their success has motivated interest and efforts in expanding the concept to several diseases including cancer, in the hope to tackle previously elusive or inadequately drugged targets and accelerate translation to clinical therapies. Some PROTACs have advanced to clinical development, confirming the efficacy and feasibility of this innovative therapeutic approach. Today, over 40 degraders, including PROTACs, are being developed in clinical trials, many for oncology indications. Although the literature is particularly abundant in reviews on PROTACs, there are currently no studies that collect data on the use of PROTACs in cutaneous melanoma, the most common and aggressive type of skin cancer. Therefore, in this comprehensive review, preclinical findings will be presented and discussed, helping to bring together studies and efforts in the rapidly evolving field of PROTACs, with regard to cutaneous melanoma. Thus, offering an opportunity for scientists and clinicians to deepen their knowledge about this field, and to shape the future of personalized cancer therapy.