International Journal of Biological Sciences最新文献

The lateral septum (LS) regulates affective-cognitive processes and is dysregulated in human psychiatric disorders. Its functional complexity stems from heterogeneous connectivities and neuronal subtype compositions across anatomical subregions. Comprehensive understanding of LS function has been hindered by the lack of a three-dimensional (3D) neuronal atlas. Moreover, the association between peripheral immune disturbances and psychiatric disorders underscores the necessity to investigate potential 3D LS neuronal heterogeneities across distinct immunological states. This study employed single-nucleus RNA sequencing to analyze LS differences in C57J, BALB/c, and nude mice with distinct immune contexts (i.e., immunocompetent, enhanced Th2 reactivity, and T-cell deficiency, respectively), and identified global alterations in non-neuronal cells alongside with neuron-specific changes. Through combining publicly available multiplexed error-robust fluorescence in situ hybridization (MERFISH) data with neural circuit tracing, this study further constructed a 3D neuronal atlas of the entire LS with their projection connectivities. Notably, an Esr1-positive neuronal subpopulation distributed in the ventral LS exhibited potential responsiveness to changes in peripheral immunity and may participate in anxiety regulation. Furthermore, the dorsal LS demonstrated heterogeneity in fear memory regulation associated with T cell homeostasis. These findings underscore the critical role of immune-neural crosstalk in emotional regulation while shedding light on potential therapeutic targets for emotion-related disorders linked to T-cell homeostatic disturbances.

BRCA1‑deficient triple‑negative breast cancer (TNBC) presents significant treatment challenges owing to the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) targets, exhibits marked molecular heterogeneity that precludes the application of effective targeted therapies, and harbors a highly immunosuppressive tumor microenvironment. Here, we used the Brca1^co/co MMTV‑Cre mouse model that recapitulates human BRCA1‑mutant TNBC, characterized by early dominance of CD11b⁺Gr‑1⁻F4/80^Low blood‑derived macrophages and subsequent enrichment of F4/80^High tissue macrophages within adipose‑rich mammary glands. PD‑1 blockade with anti‑mPD‑1 monoclonal antibodies (mAb) significantly delayed primary tumor progression, reduced proliferation marker levels (PCNA, Ki‑67), enhanced apoptosis (as indicated by increased cleaved PARP levels), and selectively impaired PI3K/AKT signaling. In a post‑resection setting, anti-mPD-1 treatment extended recurrence‑free survival rates, with elevated CD4, CD8α, and cleaved PARP levels observed in recurrent tumors. Mice with the longest relapse‑free intervals exhibited the strongest T cell marker expression. A combination of focal 20 Gy irradiation and PD-1 blockade exerted a potent synergistic effect. Specifically, irradiation reduced extracellular matrix deposition and enhanced tumor cell apoptosis (evidenced by increased cleaved caspase-3 and cytosolic PCNA) while PD-1 blockade stimulated robust inflammatory responses, in particular, expansion of CD8α⁺ T cell infiltration. These mechanistic insights align with clinical strategies for TNBC that integrate DNA damaging agents and immunotherapy and validate this model as an optimal in vivo platform for preclinical evaluation of novel treatment modalities for BRCA1‑associated breast cancer.

Emerging evidence implicates serine/threonine kinase 32C (STK32C) overexpressed in bladder cancer and brain tissues acts as a molecular target for doxorubicin resistance, yet its role in colorectal cancer (CRC) remains unclear. Thus. this study investigates the oncogenic mechanism of STK32C in CRC and its interplay with HSP90 and the PI3K/AKT/mTOR signaling axis. STK32C was markedly upregulated in CRC cell lines (HCT116, HT29, SW480, SW620) compared to normal fibroblasts (CCD-18Co) with poor prognosis. STK32C depletion suppressed proliferation, migration, and invasion, while promoting apoptosis-as evidenced by increased Bax, Annexin V, TUNEL-positive, and sub-G1 populations, alongside reduced Bcl-2, pro-Caspase-3, and pro-PARP. Mechanistically, STK32C directly bound the N-terminal domain of HSP90, as shown by immunoprecipitation, immunofluorescence, and GST pulldown assays. Consistently, STK32C depletion or HSP90 N-terminal inhibitor Ganetespib reduced STK32C and p-AKT1, while the HSP90 C-terminal inhibitor, epigallocatechin gallate (EGCG) or AKT inhibitor LY294002 did not affect STK32C, implying that STK32C acts as an upstream of AKT. Furthermore, STK32C depletion enhanced 5-fluorouracil (5-FU) efficacy, with synergistic effects confirmed by CompuSyn and SynergyFinder analysis. In vivo, STK32C depletion reduced the growth of HCT116 cells in BALB/c mice with decreased expression of STK32C, HSP90, PCNA, and AKT and activated caspase 3. Overall, these findings suggest STK32C as a novel oncogenic driver in CRC that modulates HSP90 and PI3K/AKT/mTOR signaling and highlights its potential as a therapeutic target alone or in combination with 5-FU.

Gli1 is a critical marker of diverse stem cell populations across multiple tissues and is essential for tissue regeneration. However, its functional relevance in skeletal muscle has remained largely unexplored. Here, we demonstrate that Gli1 primarily expressed in muscle stem cells (MuSCs) and fibro/adipogenic progenitors (FAPs) in skeletal muscle. Utilizing conditional knockout mouse models, we found that systemic loss of Gli1 impairs muscle regeneration; however, this effect is not attributable to MuSC-dependent mechanisms. Rather, conditional deletion of Gli1 in FAPs lead to significant regenerative impairment, characterized by aberrant FAP expansion and their enhanced adipogenic potential. In vivo, Gli1-deficient FAPs contributed to increased intramuscular adipocyte accumulation, while in vitro assays confirmed enhanced lipid droplet formation under adipogenic conditions. Mechanistically, Gli1 directly activates the transcription of the key metabolic enzyme indoleamine 2,3-dioxygenase 1 (Ido1), and inhibition or knockdown of Ido1 phenocopied the effects of Gli1 loss. Together, these findings uncover a previously unrecognized role for Gli1 in orchestrating muscle regeneration by modulating FAP fate and function, providing new insights into the cellular and molecular framework governing muscle repair.

Intrahepatic cholangiocarcinoma (ICCA), the second most prevalent primary liver malignancy, remains poorly understood at the molecular level. Research into the function of N6-methyladenosine (m6A) modification in the formation of ICCA and its potential as a therapeutic approach is being spurred by mounting evidence that it plays a crucial role in tumor biology. Immunohistochemical examination of patient samples in this investigation revealed a significant decrease in m6A methyltransferase METTL3 expression, accompanied by lower levels, which were associated with a lower overall survival rate. Functional assays demonstrated that the enforced expression of METTL3 inhibited ICCA cell proliferation and migration, while concurrently increasing the levels of the long non-coding RNA H19. Mechanistic experiments using RNA-binding protein immunoprecipitation and methylated RNA immunoprecipitation confirmed that METTL3 directly interacted with H19 and enhanced its m6A modification. Importantly, silencing of H19 reversed the growth- and migration-suppressive effects of METTL3, whereas H19 overexpression counteracted the phenotype induced by METTL3 downregulation. Further analysis revealed that the METTL3-H19 regulatory axis suppressed the expression of peroxisome proliferator-activated receptor gamma (PPARγ). Moreover, an oncolytic adenovirus engineered to overexpress H19, in combination with the PPARγ inhibitor BAY-4931, elicited potent antitumor effects both in vitro and in vivo. Collectively, these findings identify METTL3-mediated m6A modification of H19 as a critical suppressor of ICCA progression through modulation of PPARγ signaling. One interesting treatment option for ICCA may be the use of H19-armed oncolytic adenoviruses, especially when combined with PPARγ suppression.

Epithelial-mesenchymal transition (EMT) is a fundamental biological process that promotes cancer metastasis and chemoresistance. However, the therapeutic efficacy of EMT inhibitors remains limited. Ubiquitination, a critical post-translational modification, involves attaching ubiquitin molecules to proteins to regulate their function and stability. It modulates EMT by controlling key EMT transcription factors (EMT-TFs) and associated signaling pathways. Evidence indicates that ubiquitination-dependent regulation of EMT serves as a central mechanism underlying tumor metastasis and chemoresistance. Targeting specific deubiquitinases (DUBs) or E3 ligases can effectively reverse EMT-induced cancer progression and treatment resistance. These findings highlight the therapeutic potential of E3 ligase and DUB inhibitors in oncology. Collectively, ubiquitination-regulated EMT is pivotal in mediating metastasis and chemoresistance in malignant tumors. This review summarizes the molecular mechanisms of EMT and emphasizes ubiquitination's essential role in regulating EMT to promote tumor metastasis and chemoresistance. Consequently, developing inhibitors against specific E3 ligases and DUBs offers a promising strategy to improve cancer treatment outcomes.

Background: Spinal cord injury (SCI) is a neurological disorder characterized by progressive neuronal death. Notably, microglia-mediated synapse phagocytosis contributes to the disruption of the surviving neuronal network. Recovery of neurological function after SCI largely relies on the activation and remodeling of neural circuits. Magnetic stimulation has been shown to improve the reconstruction of neural synapses and neural circuits. However, the specific mechanisms by which repetitive trans-spinal magnetic stimulation (rTSMS) modulates microglial phagocytosis of synapses in SCI remain unclear. Methods: A modified version of Allen's method was used to establish an SCI model. Structural recovery was assessed using Hematoxylin-eosin and Nissl staining. Neurological function was evaluated through several assessments: the Basso, Beattie, and Bresnahan scale, the modified Rivlin inclined plate test, the horizontal ladder test, thermal pain assessment, motor evoked potential measurements, and gait analyses. Single-cell RNA sequencing was utilized to elucidate the cellular and molecular mechanisms by which rTSMS promotes recovery after SCI. Additionally, western blotting and immunofluorescence staining were performed to measure microglial phagocytosis of synapses and to investigate the expression of components of the cyclic GMP-AMP synthase (cGAS)-STING pathway. Furthermore, the STING agonist 2,3 cGAMP was used to further explore the role of the cGAS-STING pathway in the effects of rTSMS. Results: rTSMS significantly reduced the lesion area and improved functional recovery in rats subjected to SCI, and these changes correlated with enhanced synapse reservation and axon regeneration. Single-cell RNA sequencing identified microglia as the primary target cells that actively respond to rTSMS. Importantly, rTSMS effectively inhibited the phagocytosis of synapses by overactivated microglia via suppressing the cGAS-STING pathway. Moreover, 2,3 cGAMP counteracted the effects of magnetic stimulation on microglia both in vivo and in vitro. Conclusion: rTSMS mitigates SCI-induced synapse loss and neurological deficits by modulating microglial phagocytosis, a process dependent on the cGAS-STING pathway. These findings provide new insights into the mechanisms by which rTSMS exerts neuroprotective effects in the context of SCI.

Circular RNAs (circRNAs) are structurally stable and covalently-linked ring RNA molecules. Due to backsplicing, they are directly joined by phosphodiester linkage, which confers much greater stability relative to their linear mRNA counterparts. Recent studies indicate that circRNAs also encode proteins involved in mechanisms associated with the pathogenesis of various diseases, offering new treatment insights. This review briefly summarizes the history, characteristics, and functions of circRNAs; the formation and translation mechanisms of circRNA-encoded proteins; and computational and experimental techniques for identifying/predicting the protein-encoding potential of circRNAs. We also summarized their role in disease pathogenesis, which includes how they could be targeted and harnessed as novel therapeutic options for disease treatment. Finally, we stated some current limitations to studies on circRNA-encoded proteins and concluded with a discussion of future research directions to facilitate effective clinical translation.

The use of doxorubicin (DOX), a wide-spectrum antineoplastic drug, is largely limited in clinical practice because of the less than satisfactory strategies available for the prevention and treatment of doxorubicin-induced cardiotoxicity (DIC). Although gasdermin E (GSDME) has been linked to the development of several cardiovascular diseases, the role of GSDME in DIC has not been thoroughly investigated. Here, we aimed to explore the role of GSDME in the development of DIC and develop efficient and feasible targets for managing DIC. We found that GSDME was upregulated in both DOX-treated murine hearts and isolated adult mouse cardiomyocytes. Conditional Gsdme knockout in cardiomyocytes, but not myeloid cells, attenuated DOX-induced cardiac remodeling, cardiac malfunction, and cardiac fibrosis. Cardiomyocyte-specific Gsdme knockout dampened DOX-induced cardiac CCL2-CCR2 signaling and inflammation, while CCL2 inhibition or CCR2+ macrophage depletion attenuated DIC. Mechanistically, GSDME facilitated mitochondrial injury in cardiomyocytes to release mtDNA and activated the STING/NFκB pathway, further targeting the CCL2-CCR2 axis and cardiac inflammation, thereby aggravating DIC. These findings identify GSDME as a potential therapeutic target for DIC.

Iodinated contrast agents are a common cause of contrast-induced acute kidney injury (CI-AKI), yet the underlying mechanisms remain unclear. We found that circSAMD4 is markedly upregulated in renal tubular epithelial cells (RTECs) from iohexol-induced CI-AKI mice and patients diagnosed with acute tubular injury (ATI). Silencing circSAMD4 alleviated kidney injury and tubular cell death in CI-AKI mice, whereas its overexpression promoted apoptosis in iohexol-treated RTECs. Mechanistically, circSAMD4 binds to cold-inducible RNA-binding protein (CIRBP) and inhibits its nuclear import. Renal tubule-specific Cirbp deletion mitigated CI-AKI, while CIRBP overexpression abolished the protective effects of circSAMD4 knockdown against iohexol-induced apoptosis. CircSAMD4 upregulation in iohexol-treated RTECs was driven by serine/arginine-rich splicing factor 3 (SRSF3) downregulation. Similar molecular alterations in clinical samples correlated with kidney function decline. These findings identify the SRSF3/circSAMD4/CIRBP axis as a novel pathogenic mechanism in CI-AKI and highlight circSAMD4 as a promising therapeutic target.