Cellular and Molecular Life Sciences最新文献

Toxoplasma gondii chronically infects the central nervous system (CNS), but the mechanisms enabling its traversal of the blood-brain barrier (BBB) remain unclear. Here, we investigated BBB penetration using brain endothelial spheroids and cerebral tissue-derived organoids that recapitulate three-dimensional barrier features. We show that T. gondii tachyzoites efficiently colonize spheroids, without detectable barrier disruption or obligatory parasite replication. Following direct transmigration, tachyzoites invaded and replicated within deeper cell layers. Type I strains (RH, CPS) exhibited higher colonization efficiency than type II strains (PRU, ME49), independent of replication. In contrast, when spheroids were exposed to T. gondii-infected dendritic cells (DCs), both strain types were transported similarly into deep cellular layers. Infected DCs adopted an amoeboid-like migratory phenotype that facilitated parasite transport and subsequent dissemination after egress. Colonization was attenuated by ICAM-1 blockade or heparin treatment, while the parasite effector GRA15, despite modulating DC-endothelial adhesion, did not significantly impact intratissue migration. In contrast, deletion of the effector TgWIP markedly reduced the number of infected DCs entering the spheroids. Similar colonization dynamics were observed in murine cerebral organoids. Collectively, these findings highlight spheroid and organoid models as robust systems for uncovering the cellular and molecular mechanisms underlying T. gondii BBB traversal and CNS colonization.

ZDHHC4, a palmitoyl transferase belonging to the DHHC family, is crucial in cells by catalyzing palmitoylation of proteins, thereby regulating their function and localization. However, its role in melanoma is not well understood. Here, our research determined that ZDHHC4 expression was upregulation in human melanoma specimens and cells. Functional studies reveal that knocking down ZDHHC4 inhibits cell proliferation, migration and invasion of melanoma cells. Moreover, we performed mass spectrometry analysis and found that ZEB-2 is a substrate of ZDHHC4. ZEB-2 interacted with ZDHHC4 through its N-terminal sequences, which promotes the ZDHHC4-mediated palmitoylation of ZEB-2 at C478, facilitating ZEB-2 deubiquitination and its protein stability. This key modification is required for epithelial-to-mesenchymal transition (EMT) in melanoma cells. Furthermore, we found a positive correlation between the expression levels of ZDHHC4 and ZEB-2 in clinical melanoma samples. In summary, our results provide a deeper understanding of mechanism regulating ZDHHC4 in melanoma, suggesting that targeting ZDHHC4 may offer novel therapeutic strategies by suppressing tumor growth and metastasis through the disruption of ZEB-2 palmitoylation process.

High mobility group A1 (HMGA1), a non-histone chromatin structural protein encoded by the HMGA1 gene, plays a critical role in cancer. Recent studies have increasingly focused on its functions in genomic stability and cell death, revealing its involvement in tumorigenesis, cancer progression, and chemotherapy resistance. Consequently, inhibiting HMGA1 represents a promising strategy for developing novel cancer therapies. This review summarizes the cellular and molecular functions of HMGA1 in regulating genomic integrity and cell death in cancer. Furthermore, we discuss current HMGA1-targeting strategies, with emphasis on approaches leveraging its structural and functional characteristics, aiming to provide new insights for future research on HMGA1-targeted cancer therapies.

Background: Immunosuppression is a distinctive condition resulting from sepsis, marked by impaired immune response and immune dysregulation, with a poor prognosis. PRC1, a mitotic regulatory protein, is associated with immune suppression within the tumor microenvironment. However, the role of PRC1 in septic immunosuppression remains unclear. This research aimed to explore the implication and potential mechanism of PRC1 in septic immunosuppression.

Methods: Dataset GSE95233 and GSE65682 were used to validate the expression and prognostic value of PRC1 in sepsis patients. LPS was used to stimulate naïve or endotoxin-tolerant THP-1 and BMDMs. PRC1 expression was measured in by RT-qPCR and Western blot. Small interfering RNA was used for PRC1 knockdown in THP-1. The phosphorylated STAT3 and active β-catenin was detected by Western blot. The expression levels of cytokines and surface markers of macrophages were validated by RT-qPCR. β-catenin inhibitor MSAB and agonist SKL2001 were used to explore the functional relationship among relevant molecules.

Results: PRC1 expression was increased in sepsis non-survivors in both dataset GSE95233 and GSE65682, and increased PRC1 expression was associated with increased 28-days septic mortality. PRC1 expression was elevated in endotoxin-tolerant macrophages rather than naïve macrophages. Sustained phosphorylation of STAT3 was detected in endotoxin-tolerant macrophages. Increased PRC1 expression maintained the phosphorylated STAT3 level via a β-catenin-dependent mechanism, which was reversed by β-catenin inhibitor MSAB. PRC1 knockdown could reduce STAT3 phosphorylation and restore inflammatory responses in endotoxin-tolerant macrophages, while this effect was eliminated by β-catenin agonist SKL2001. Septic microenvironment promoted the expression of PRC1 in endotoxin-tolerant macrophages.

Conclusion: Our data demonstrated that PRC1 is upregulated in endotoxin-tolerant macrophages, and that increased PRC1 expression maintains STAT3 activation via a β-catenin-dependent mechanism and impairs inflammatory response of macrophages during septic immunosuppression. Targeting PRC1/β-catenin/ STAT3 could represent a novel strategy for the management of septic immunosuppression and restore the inflammatory response of endotoxin-tolerant macrophages.

The African swine fever virus (ASFV) -encoded late structural protein pA104R is a putative histone-like protein, which is also a DNA-binding related protein required for ASFV DNA replication, transcription, and genome packaging. However, the molecular mechanism underlying pA104R-host protein interactions remain unknown. To identify proteins potentially interacting with ASFV-pA104R, a primary porcine alveolar macrophage (PAM) cDNA yeast two-hybrid library was constructed, and the pig E3 ubiquitin ligase RING-finger protein 2 (RNF2) was identified, which specifically negatively regulates the proliferation of ASFV. Mechanistically, RNF2 inhibits ASFV replication by promoting the proteasomal degradation of ASFV-pA104R through K48-linked ubiquitination at pA104R lysine 5 (K5). Further studies showed that the K5R mutation impairs the interaction between pA104R and RNF2 and antagonizes for pA104R degradation by RNF2. An ASFV mutant carrying a pA104R point mutation (ASFV CN/SC/2019 pA104R-K5R) was generated based on the ASFV CN/SC/2019 (wild-type) strain. Furthermore, our findings indicate that ASFV CN/SC/2019 pA104R-K5R enhances viral replication and virulence, potentially by increasing viral transcription and/or modulating the host immune response. Accordingly, compared with the parental strain, ASFV CN/SC/2019 pA104R-K5R was more pathogenic and severe lesions in swine. Collectively, our study identifies an intrinsic antiviral protein RNF2 that mediates ASFV CN/SC/2019 pA104R-K5 site ubiquitination emerges as a potential determinant of viral replication and pathogenicity.

Shallow trophoblast invasion and improper maternal spiral artery remodeling are the primary mechanisms underlying the development of preeclampsia (PE). Bone morphogenetic protein 6 (BMP6) is a proinvasive and proangiogenic factor in vitro; however, its regulatory mechanisms in trophoblast behavior and its role in PE development remain unclear. In this study, primary human trophoblasts and the HTR8/SVneo cell line were utilized asin vitrostudy models. Bulk RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq) data were analyzed to explore the expression patterns of BMP6-regulated genes. We found that BMP6 treatment significantly upregulated inhibitor of DNA-binding 1 (ID1) in human trophoblasts. ID1 depletion abolished both basal and BMP6-induced trophoblast invasion and vascular mimicry. Mechanistically, ID1-mediated upregulation of serpin family E member 2 (SERPINE2) and placental growth factor (PlGF) was essential for BMP6-induced trophoblast invasion. In third-trimester placentas, BMP6 mRNA and protein levels were significantly elevated in PE compared with controls. In the adenovirus-expressing fms-like tyrosine kinase-1 (Ad Flt1)-induced rat model of PE, both circulating BMP6 and placental Bmp6 expression were increased in PE rats in late pregnancy. Significantly, BMP6 supplementation during early pregnancy (gestational days 10-13) alleviated maternal hypertension and fetal growth restriction in the PE model. These findings suggest BMP6 promotes trophoblast invasion through ID1-mediated upregulation of SERPINE2 and PlGF. The late-gestation upregulation of BMP6 may represent a compensatory response to shallow trophoblast invasion in PE. Early BMP6 supplementation mitigates PE-related phenotypes in a rat model, highlighting BMP6 as a potential therapeutic target for the prevention and management of PE.

The imbalanced expression of interferon regulatory factor (IRF) 4 and IRF8 in activated B cells significantly influences their differentiation and promotes the development of immune-related diseases. Restoring abnormal B cells to appropriate responses may treat these diseases. In this study, an oligodeoxynucleotide (ODN) S2, designed according to the consensus sequence recognized by IRFs in interferon-stimulated response elements, was used as an immunomodulator to investigate its effects on mouse splenic B cells stimulated with the TLR9 agonist CpG ODN, either alone or in combination with antigen, and to explore its underlying mechanisms. The results showed that S2 had a significant negative regulatory effect on CpG ODN induced B cell activation. It also significantly downregulated the production of IL-6 and the percentage of IL-6⁺ B cells in splenocytes stimulated by CpG ODN, but significantly upregulated the percentage of IL-10⁺ B cells. Interestingly, S2 impaired antibody production both in vitro and in vivo, but rescued mice from lethal inflammatory responses. Further studies showed that S2 could bind IRF4 and IRF8 with high affinity, slightly upregulate phosphorylated IRF4, reduce the expression and nuclear translocation of IRF8, and alter the proportion of IRF4⁺, IRF8⁺ or double-positive B cells in spleen cells induced by CpG ODN. These results suggest that S2 acts as a decoy directing some B cells to differentiate into IL-10-producing Breg-like cells rather than plasma cells by restoring the TLR9 signal-induced IRF4 and IRF8 ratio imbalance. This indicates its potential as an immunomodulator for the treatment of diseases associated with B-cell abnormalities.