Epithelial cell polarity is fundamental for embryonic development and organ function. During organogenesis, epithelia often develop from unpolarized precursor cells. How mammalian epithelial cells establish polarity de novo is unclear, in part due to challenges of observing this process in real time in nontransformed cells. Here, we leverage 3D spheroid culture of mouse embryonic stem cells, fluorescent protein knock-in, and live imaging to study epithelial polarity establishment. We show that apical myosin activity, regulated by myosin light chain kinase (MLCK), is crucial for proper epithelial polarity in this system. MLCK-dependent actin flows carry ZO-1, a tight junction component, to the apical junction. A second pool of myosin, regulated by Rho kinase, localizes basally and modulates ZO-1 recruitment to the membrane. MLCK inhibition also disrupts localization of atypical protein kinase C and podocalyxin, supporting a broader role of MLCK-dependent myosin in establishing the apical membrane. Our results support a model in which distinct apical and basal actomyosin pools coordinate epithelial polarity establishment.

CCDC181, a kinocilium-localization protein, is dispensable for hair bundle development and auditory perception.

Cancer immunotherapy, including immune checkpoint inhibitors (ICIs) and chimera-antigen receptor (CAR)-T cell therapy, has achieved substantial clinical success. However, response rates remain limited in many patients due to tumor-intrinsic immune evasion and immune cell dysfunction within the tumor microenvironment (TME). Rho family small GTPases are key signaling regulators of cytoskeletal dynamics, intracellular trafficking, transcription, and metabolism in cancers. Emerging evidence implicates Rho GTPase signaling in mediating immunotherapy efficiency through its context-dependent functions. Individual Rho GTPases modulate immunotherapy responses in tumor cells and various immune cells through actomyosin-mediated chemotaxis, cell junctions, cell polarity, and gene/epigenetic networks, among other pathways. The present review summarizes both the direct evidence linking Rho GTPases in tumor cells to immunotherapy responses and the indirect role of the selective Rho GTPase signaling network in various immune cells, with a focus on the recent progress in understanding the molecular mechanisms and associated outcomes of the ICIs and CAR-T cell therapies. We highlight current knowledge gaps at the intersection of Rho GTPase biology and cancer immunology and discuss therapeutic implications, proposing that selective modulation of specific Rho GTPase signaling pathways in tumor or TME immune cells represents a promising strategy to improve immunotherapy efficiency.

Role of SERPINE1 (PAI-1) in gastric cancer: Molecular mechanisms, prognostic marker potential, and targeted therapeutic strategies.

Appalabhotla et al. (https://doi.org/10.1083/jcb.202507177) engineer a light-controlled version of PLC-γ1 (PLC-γ1) and show that activating it in an illuminated region of the cell membrane drives directional migration. The work redefines PLC-γ1 as an instructive signal in control of cell polarity.

Background Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality worldwide, with a poor survival rate despite advances in therapy. Metabolic reprogramming, particularly involving lactate transport, plays a critical role in HCC progression. Monocarboxylate transporter 4 (MCT4) is a key lactate exporter often overexpressed in cancers, yet its precise role in HCC pathogenesis and immune modulation remains incompletely defined. Methods We integrated bioinformatic analyses of multiple datasets (TCGA-LIHC, GSE46408, GSE36411) with experimental validation in HCC cell lines (Huh7, MHCC97-H) and a murine xenograft model. Functional assays including wound healing, Transwell invasion, Western blot, and flow cytometry were employed. Immune cell infiltration and polarization were analyzed via CIBERSORT and single-cell RNA sequencing data (GSE282701). Results MCT4 was identified as a prognostic hub gene among lactate metabolism-related genes (LMRGs) and was significantly upregulated in HCC tissues, correlating with advanced tumor stage and poor survival. Gene Set Enrichment Analysis (GSEA) revealed a strong association between MCT4 expression and matrix metalloproteinase (MMP) pathways. In vitro , MCT4 knockdown downregulated MMP1, MMP2, and MMP9 expression and suppressed HCC cell migration and invasion. Furthermore, high MCT4 expression was linked to an immunosuppressive tumor microenvironment characterized by M2 macrophage polarization. In vivo , MCT4 knockdown inhibited tumor growth and reduced infiltration of CD206 + M2 macrophages. Conclusions Our findings demonstrate that MCT4 drives HCC progression through two complementary mechanisms: enhancing MMP-mediated invasion and metastasis, and promoting immunosuppressive M2 macrophage polarization. These results nominate MCT4 as a promising therapeutic target for restoring antitumor immunity and inhibiting metastasis in HCC.

Thyroid cancer exhibits substantial heterogeneity in its tumor immune microenvironment (TIME), which critically shapes disease progression and therapeutic responsiveness. While most differentiated thyroid cancers (DTCs) remain indolent, a subset evolves into radioiodine-refractory disease or progresses to poorly differentiated (PDTC) and anaplastic thyroid carcinoma (ATC), characterized by aggressive behavior and limited treatment options. Emerging evidence suggests that this transition is accompanied by dynamic immune reprogramming rather than static immune evasion. In this review, we propose a stepwise model of immune evolution in thyroid cancer, spanning from autoimmune-driven inflammation in chronic lymphocytic thyroiditis (CLT) to immune-exhausted states in advanced tumors. We systematically characterize immune cell composition, functional states, and regulatory networks across disease stages, highlighting key shifts in antigen presentation, T-cell functionality, and myeloid cell polarization. Building on this framework, we integrate tumor immune phenotypes (“hot”, “altered”, and “cold”) with actionable biomarkers, including PD-L1 expression, tumor mutational burden, IFN-γ signatures, M2 macrophage-related signature, and tertiary lymphoid structures. We further map these immune contexts to rational therapeutic strategies, encompassing immune checkpoint blockade, combination regimens with tyrosine kinase inhibitors or radiotherapy, and emerging approaches such as innate immune activation and adoptive cell therapies. By linking immune evolution with therapeutic vulnerabilities, this review provides a translationally relevant framework for precision immunotherapy in thyroid cancer and highlights future directions for overcoming resistance in advanced disease.

Gypenosides ameliorate depression by modulating microglial state transition via the NLRP3/Caspase-1/ASC signaling pathway.

Fatty acid oxidation and inflammatory bowel disease: Highlighting the roles of pathogenesis and treatment.

Periodontitis, caused by periodontal pathogens such as Porphyromonas gingivalis, is a risk factor for Alzheimer's disease (AD) progression. Neutrophils, which are abundant in patients with periodontitis, release neutrophil extracellular traps (NETs) to resist microbial infection. We explored the mechanism and effects of P. gingivalis-induced NETs on the relationship between periodontitis and neuroinflammation. A murine periodontitis model was established via oral local application of P. gingivalis with or without tak242 (TLR4 inhibitor). Maxillary bones were evaluated via micro-computed tomography. The proportion of neutrophils was determined by flow cytometry. NET formation and morphology were analyzed via a cell-free DNA kit, a neutrophil elastase enzyme-linked immunosorbent assay (ELISA) and myeloperoxidase ELISA kit, reverse transcription polymerase chain reaction (RT-PCR), western blotting and immunofluorescence. Behavior tests were used to investigate cognitive ability. Neuroinflammation was assayed by immunohistochemistry (IHC) and RT-PCR. Amyloid precursor protein (APP) processing was measured by IHC. In vitro experiments explored the functional mechanism underlying the effects of P. gingivalis-induced NETs on the neuron-glia unit. We observed significant alveolar bone resorption with elevated neutrophil count and increased NET formation in mice with periodontitis. Cognitive abilities were impaired by periodontitis. Neuroinflammation manifested as glia activation and upregulated inflammatory cytokines, and APP processing was altered by the elevated expression of APP and PSEN1. These changes were specifically reversed by tak242. In vitro, P. gingivalis-induced NETs mediated M1 polarization in BV2 cells and changed APP processing in N2a cells, along with the activation of TLR4/Myd88/NF-κB and GSK3β/Akt, which is consistent with the in vivo findings. In conclusion, P. gingivalis-induced NETs play pivotal roles in the relationship between neuroinflammation and cognitive impairment. Furthermore, the effects of P. gingivalis-induced NETs on neuron-glia unit were related to TLR4 activation.

PD-1/PD-L1 mediated glycolysis-driven M1 polarization of Hofbauer cells impairs placental and fetal development following maternal mixed bisphenols exposure.

In vitro alveolar-capillary models based on co-culturing the alveolar epithelial cell line H441 and primary pulmonary microvascular endothelial cells (HPMEC) are a widely used platform for evaluating the function of the alveolar barrier. However, the relatively thick synthetic membranes that are used as substrates in most approaches fail to mimic the properties of the natural basement membrane, thereby decreasing the physiological relevance of those models. We investigated the potential of the FN-silk membrane to support an in vitro alveolar-capillary model. The FN-silk membrane is micrometer-thin, fibrillar, constructed from a functionalized recombinant spider silk protein, and has been previously shown to be a potent basement membrane mimic supporting physiologically relevant in vitro models of various barrier tissues (i.e., blood vessel, skin, BBB, and kidney). Herein, it supported alveolar epithelial and endothelial barrier formation, surfactant protein B and C (SPB, SPC) production, and epithelial cell polarization, detected with immunofluorescence. Notably, we also demonstrated for the first time, to our knowledge, that key events related to alveologenesis (i.e., cell hollowing, lumen formation, septation, and α-SMA expression) can take place in an in vitro model. This further highlights the ability of the FN-silk membrane to recapitulate the complicated alveolar milieu and expanding the known potential of the H441 cell line, which to our knowledge, has not been previously reported to enable modeling the alveolar tissue 3D morphology. We propose the FN-silk-based alveolar-capillary model as an advanced in vitro model that can be used as a potent tool in respiratory, developmental biology, and regenerative medicine research.

Planar cell polarity-directed cell crawling drives polarized epithelial morphogenesis.

Cell polarity is essential for the formation and function of animal tissues. Atypical protein kinase C (aPKC), its cofactor PAR-6, and scaffold protein PAR-3 regulate cell polarity in many different animal cell types. PAR-3 oligomerization is important to establish cell polarity, but how oligomerization relates to the assembly of the PAR-3/aPKC/PAR-6 complex is still unclear. Here, we use in vivo and ex vivo single-molecule techniques to demonstrate cooperativity between PAR-3 oligomerization and its binding to aPKC/PAR-6 in the Caenorhabditis elegans zygote. Using genetic perturbations, we present evidence that aPKC and PAR-6 have independent binding sites for PAR-3. We propose that multivalency drives cooperativity because a single aPKC/PAR-6 heterodimer can interact simultaneously with multiple PAR-3 molecules in an oligomer. Although single binding site mutations do not fully eliminate PAR-3/aPKC/PAR-6 binding, they do abolish anterior-posterior polarity, suggesting that PAR-3/aPKC cooperativity contributes to PAR-3 function during polarity establishment. Finally, PAR-3/aPKC cooperativity is downregulated in polarity maintenance, and this downregulation depends on the mitotic kinase PLK-1. Together, our results show how cells can developmentally regulate multivalent assembly of a key polarity complex to achieve timely segregation of cell fate determinants.

Medulloblastoma, the most common malignant pediatric posterior fossa tumor, exhibits metabolic reprogramming and tumor immune microenvironment heterogeneity in non-WNT/non-SHH subgroups, yet the interplay between these features remains poorly defined. Revealing potential molecular features and hidden therapeutic target, we integrated the transcriptomic data of non-WNT/non-SHH medulloblastoma from GEO and EMBL-EBI databases. Through examination of the Grp3/4 transcriptional continuum, we identified PCK2 (a key gene in the TCA cycle with the highest correlation with continuum score). We validated PCK2 as a driver of proliferation, migration, invasion, glycolysis, and M2 macrophage polarization in MYC-amplified MB cells through short hairpin RNA knockdown experiments. Together, our findings establish metabolic-TIME crosstalk as a prognostic determinant and proffer PCK2 as a therapeutic target for aggressive MB subtypes, offering insights into metabolic subtyping and precision therapy strategies to improve clinical outcomes.

To clarify whether Qingshen Granules (QSG) inhibits renal fibrosis by regulating Akt3-mediated macrophage polarization. Adult C57BL/6 mice were randomized into Sham group, unilateral ureteral obstruction (UUO) model group, and UUO with QSG treatment group (n=6) for treatment with daily gavage of distilled water or QSG (4.0 g/kg) as indicated for 2 weeks. In AAV9 experiments, the mice received intrarenal injections of AAV9-shRNA(Akt3)-GFP for Akt3 knockdown or AAV9-shRNA-GFP (negative control) 2 weeks before sham operation or UUO modeling. After the treatments, the mice were examined for renal fibrosis, renal function, and macrophage polarization using HE staining, Masson staining, ELISA, Western blotting, RT-qPCR, immunohistochemistry, immunofluorescence staining, and flow cytometry. In the cell experiment, TGF‑β1-induced HK-2 cells were co-cultured with THP-1-derived macrophages, and the effects of QSG-medicated rat serum on cell viability, proliferation, and macrophage polarization were evaluated using CCK-8 and EdU assays, Western blotting and flow cytometry. Compared with the sham-operated mice, the UUO mice showed impaired renal function, renal tubular injury, collagen deposition, upregulated expressions of IL-6 and TNF-α mRNA and α-SMA protein, and downregulated E-cad protein expression, which were significantly improved by QSG treatment. In AAV9 experiments, the UUO mice with control virus injection showed obvious renal fibrosis and increased M1 macrophages, while AAV9-shRNA(Akt3)‑GFP injection significantly alleviated renal fibrosis and inhibited M1 macrophage polarization without affecting M2 macrophages. In the co-cultured cells, treatment with QSG-medicated serum significantly reversed TGF-β1-induced reduction of HK-2 cell viability and proliferation, upregulated Akt3 and α‑SMA expressions, downregulated E-cad expression, and inhibited M0-to-M1 polarization of THP-1 cells induced by TGF‑β1-treated HK-2 cells. QSG alleviates renal fibrosis in UUO mice by inhibiting Akt3-mediated M1 macrophage polarization.

Healthy proliferation requires the coordination of cell cycle progression with cell polarity. In budding yeast, polarity is established when G1-cyclin-Cdc28Cdk1 triggers Cdc42 activation to generate a cell pole that is used as an axis for growth and division. While polarity defects delay the cell cycle temporally, permitting error correction, it is unknown if Cdc28Cdk1 directly rectifies errant polarity. Here, we identify an adaptive response where G1-cyclin-Cdc28Cdk1 participates in error correction via the augmentation of its kinase activity towards substrates that activate Cdc42. The response involves temporal and spatial cell cycle reconfiguration via extended G1 cyclin expression, nucleocytoplasmic rerouting and signaling. However, this strategy has a cost: if the defect is irreparable, high G1-cyclin levels enforce inexorable cell cycle commitment in the absence of a daughter cell, generating multinucleate cells. G1-cyclins therefore not only trigger G1 events, but also monitor their execution, employing feedback to coordinate polarity with cell cycle progression.

The heterogeneity of lung adenocarcinoma (LUAD) makes it challenging to fully comprehend its development. Basement Membrane (BM) promotes cell polarity and has a function in cell development. A single-cell transcriptional profile of LUAD was established to investigate the heterogeneity of the tumour microenvironment(TME). Subsequently, the cell differentiation status and intercellular communication analysis in LUAD microenvironment were analysed. A total of 250 genes were associated with the BM and involved in cell trajectory differentiation. Next, the variation in immune checkpoint gene expression levels and immunotherapy response between groups was analysed using consensus clustering. Weighted gene co-expression network analysis (WGCNA) was applied to identify genes from the modules that showed a strong correlation with clinical characteristics. Moreover, based on our thorough bioinformatics study, we established the prognostic signature of Basement Membrane -related genes (BMRGs) using genes with strong prognostic importance. The MIF signalling pathway was found to be significantly activated in the TME. Cell differentiation trajectory analysis identified five subpopulations with distinct differentiation states. Every cluster has distinctive individual clinical characteristics and reflects a different immunological microenvironment. A prognosis model was created using six BMRGs with the most significant predictive power for survival. The model of risk score acts as a stand-alone prognostic factor, and the model is able to forecast patient prognoses with accuracy, which helps investigate more effective immunotherapy strategies.It also has a significant impact in TME.

Background Sepsis is a systemic inflammatory response caused by infection, often accompanied by myocardial injury. Studies have shown that methylation modifications are associated with immune cell polarization, but their role in sepsis-induced myocardial injury remains unclear. This article aimed to investigate how methylation modifications regulate macrophage polarization through the phosphoinositide 3-kinase/protein kinase B/mammalian target of Rapamycin (PI3K/AKT/mTOR) signaling pathway, thereby influencing sepsis-induced myocardial injury. Methods Sepsis was induced by lipopolysaccharide (LPS), and interventions included methylation inhibition, PI3K inhibition, and Interleukin-10 (IL-10) overexpression. Myocardial injury and immune responses were assessed by measuring physiological indicators, myocardial injury markers, hematoxylin-eosin (HE) staining, immunohistochemistry, and immunological assays in rats. Results After sepsis induction, myocardial injury was more pronounced in the methylation inhibition and PI3K inhibition groups, while the IL-10 overexpression group exhibited milder injury. Immunological assays showed that the proportion of M1 macrophages was increased in the methylation and PI3K inhibition groups, while the IL-10 overexpression group maintained a higher proportion of M2 macrophages. Conclusion Methylation modifications could regulate macrophage polarization through PI3K-related signaling pathways, thereby aggravating sepsis-induced myocardial injury.IL-10, by promoting M2 macrophage function, attenuates myocardial injury and holds potential therapeutic value.

Plasticity transitions during carcinoma progression generate fetal-like progenitor states with metastatic capacity. How these progenitors emerge and persist during tumor progression remains unclear. Here, we elucidate a process that drives the emergence of SOX2+ metastatic progenitors in lung adenocarcinomas (LUAD). LUAD cells at the tumor invasive front and distant metastases express the cell adhesion molecule L1CAM, a marker of regenerative epithelial progenitors and a mediator of cell-basement membrane and cell-cell interactions, as well as the proliferation of extravasated micrometastatic cells. We now identify a distinct and broader role of L1CAM as promoter of the SOX2+ LUAD progenitor state. We show that L1CAM at cell-cell interfaces promotes the assembly of the planar cell polarity (PCP) complex in metastatic LUAD progenitors. L1CAM-dependent PCP acting through a non-canonical WNT signaling activates c-Jun, which cooperates with the chromatin remodeling factor CHD1 to drive SOX2 expression and metastatic activity. This axis sustains the tumor-initiating and regenerative capacity of LUAD progenitor cells. By illuminating the role of L1CAM and PCP signaling in the generation of SOX2+ LUAD progenitors, our findings identify potential new targets to treat metastatic cancer.