Cell and Bioscience最新文献

Background: In stem cell biology, a long-held structure-function relationship is the domed colony morphology and naïve pluripotency for mouse or human pluripotent stem cells. This link has provided a convenient way to recognize bona fide naïve pluripotent cells during derivation, passaging and characterization. However, the molecular basis of this link remains poorly understood.

Results: We show that a loss of domed morphology may not impact the overall genetic architecture of naïve pluripotency in mouse embryonic stem cells (mESCs). We first generated stable mESC lines by knocking out Myh9 that encodes non-muscle myosin heavy chain IIA, resulting in colonies deprived of the typical domed morphology, but competent to differentiate into the three germ layers and chimeric mice. Modulating cell morphologies with inhibitors against kinases known to regulate myosin pathway also phenocopy the knockout in wild type mESCs.

Conclusions: These results provide evidence that the domed morphology and potency can be uncoupled and suggest that domed structure is not a pre-requisite for acquiring and maintaining naïve pluripotency.

Background: The heterodimeric FACT complex (SSRP1/Ssrp and SUPT16H/Dre4) is primarily recognized as a chromatin remodeler. While mutations in this complex are linked to human intellectual disability and it maintains neural stem cell fate in flies, single-cell RNA sequencing reveals robust FACT complex expression in human testicular germ cells. Nevertheless, its specific functions during spermatogenesis remain unexplored.

Methods: This study utilized Drosophila melanogaster as a model to investigate the roles of FACT complex during spermatogenesis. Germline-specific and somatic-specific knockdowns of Ssrp and dre4 combined with immunostaining were performed to assess their functions. Bulk and single-cell RNA sequencing analyses were conducted on Ssrp-deficient testes to investigate transcriptomic changes.

Results: Our study uncovers context-dependent functions for Ssrp. In testis somatic cells, Ssrp collaborates with Dre4 to sustain cyst stem cell populations via estrogen-related receptor-mediated glycolytic activation. Remarkably, germline Ssrp operates independently of Dre4, governing transit-amplifying divisions and meiotic progression. Germline-specific Ssrp depletion, but not dre4 knockdown, induces male sterility, characterized by spermatogonial accumulation, mitotic asynchrony, and meiotic arrest within primary spermatocytes. Bulk and single-cell RNA sequencing analyses of Ssrp-deficient testes reveal systemic transcriptomic dysregulation, including suppression of metabolic programs (glycolysis and oxidative phosphorylation) and activation of MAPK/EGFR signaling. Ssrp loss disrupts sister centromere cohesion during meiosis I, as well as diminished ATP levels and aberrant CENP-A accumulation, suggesting a dual regulatory nexus linking energy metabolism to chromosomal stability.

Conclusions: This work reveals previously unknown, context-dependent functions of Ssrp during Drosophila spermatogenesis. Ssrp emerges as a multifunctional orchestrator essential for both somatic and germline compartments of germline development. These findings provide crucial foundational insights into reproductive disorders associated with Ssrp dysfunction and underscore the importance of the FACT complex in male germ cell development.

Background: Cardiac remodeling underlies many cardiovascular diseases and is characterized by cardiomyocyte hypertrophy, apoptosis, and interstitial fibrosis, leading to structural and functional deterioration of the heart. Angiotensin II (Ang II), a component of the renin-angiotensin system, drives pathological remodeling through hypertrophy and fibrosis. La-related protein 1 (LARP1), an RNA-binding protein involved in post-transcriptional regulation, has been implicated in cancer biology but its role in cardiovascular disease is largely unexplored. This study investigates the role of LARP1 in regulating Ang II-induced cardiac remodeling and its interaction with ATP2A2, a gene essential for calcium homeostasis.

Methods: Human cardiac tissues from hypertrophic cardiomyopathy patients and healthy controls were analyzed for LARP1 mRNA and protein expression. A murine model of Ang II-induced cardiac hypertrophy was established, and LARP1 expression was modulated using adeno-associated virus serotype 9 (AAV9)-LARP1 and gene-deficient mice. Primary cardiomyocytes and cardiac fibroblasts were treated with Ang II to study LARP1 function in vitro. RNA immunoprecipitation, RNA pull-down, and actinomycin D assays were performed to investigate the interaction between ATP2A2 mRNA and LARP1 protein. Cardiac function, hypertrophy, and fibrosis were evaluated through echocardiography, histological staining, and molecular analyses.

Results: LARP1 mRNA and protein expression were significantly downregulated in hypertrophic human and murine cardiac tissues and in Ang II-treated cardiomyocytes. LARP1 overexpression alleviated Ang II-induced cardiac remodeling, as evidenced by reduced cardiomyocyte size, fibrosis, and normalized expression of hypertrophy markers. In vivo, LARP1 overexpression improved cardiac function and reduced pathological changes in Ang II-treated mice. ATP2A2 was identified as a downstream target of LARP1, with LARP1 overexpression enhancing ATP2A2 mRNA stability and expression. Furthermore, ATP2A2 overexpression reversed hypertrophic and fibrotic changes in LARP1-deficient cardiomyocytes and mice, underscoring its critical role in mediating LARP1 protective effects.

Conclusions: LARP1 alleviates Ang II-induced cardiac remodeling in vivo and in vitro, potentially by stabilizing ATP2A2 mRNA and enhancing its expression, thereby reducing pathological remodeling. These findings establish LARP1 as a promising therapeutic target for preventing cardiac remodeling and highlight ATP2A2 as a key mediator of its protective effects. Future studies should explore the therapeutic potential of LARP1-based interventions in cardiovascular disease.

Objective: Ischemic stroke is a leading cause of neurological disability and death worldwide, posing a substantial threat to human health. Tripartite motif-containing protein 7 (Trim7), an E3 ubiquitin ligase, is involved in the progression of various diseases, but its role in ischemic stroke remains unknown. This study aims to investigate the functional significance and molecular mechanism of Trim7 in ischemia-induced neuronal injury.

Methods: Trim7 knockout mice underwent transient middle cerebral artery occlusion-reperfusion, and adenovirus-mediated Trim7 knockdown or overexpression was performed in rat primary cortical neurons subjected to oxygen-glucose deprivation/reoxygenation. Ferroptosis markers, redox status, and neuronal injury were systematically evaluated. The interaction between Trim7 and heat shock protein family member A5 (HSPA5) was examined using co-immunoprecipitation, GST pull-down, and ubiquitination assays.

Results: Trim7 protein was significantly upregulated in cerebral ischemia-reperfusion models. Trim7 deletion or knockdown alleviated neuronal injury, reduced lipid peroxidation and inflammation, and restored glutathione peroxidase 4 (GPX4) protein expression and activity, thereby suppressing ferroptosis. In contrast, Trim7 overexpression exacerbated ferroptotic and inflammatory responses. Mechanistically, Trim7 directly interacted with HSPA5 via its PRY/SPRY domain and the substrate-binding domain of HSPA5, and promoted K48-linked polyubiquitination of HSPA5, leading to its proteasome-dependent degradation.

Conclusion: This study is the first to identify the Trim7-HSPA5-GPX4 axis as a previously unrecognized regulatory pathway that promotes ischemic-reperfusion nuernoal injury through ferroptosis. These findings provide novel mechanistic insights into the pathogenesis and potential therapeutic strategies of ischemic stroke.

Background: Regulatory T cells (Tregs) have been documented to accumulate in damaged myocardial tissue, where they play a pivotal role in attenuating excessive inflammatory responses during myocardial ischemia/reperfusion (I/R) injury. Concurrently, soluble receptor for advanced glycation end-products (sRAGE) has been demonstrated to alleviate myocardial I/R injury by suppressing inflammation, suggesting a potential involvement of Tregs in the inhibitory effects of sRAGE on myocardial I/R injury.

Methods: I/R surgery or glucose deprivation/reoxygenation was employed to explore myocardial injury and the related mechanisms by using cardiomyocyte-specific sRAGE knock-in mice or cultured cardiomyocytes. Potential molecular mechanisms were analyzed via western blotting, immunohistochemistry, and flow cytometric analysis.

Results: The findings revealed that sRAGE overexpression significantly increased the numbers of Tregs. Depletion of Tregs abrogated the protective effects of sRAGE against I/R-induced cardiac dysfunction, myocardial fibrosis, and inflammatory response in cardiac-specific sRAGE transgenic mice. Mechanistically, sRAGE was found to enhance the expression of programmed cell death ligand 1 (PD-L1) and its upstream JAK2/STAT3 signaling axis, thereby facilitating CD4⁺ T cells differentiation into Tregs within myocardial tissue during I/R.

Conclusions: The study demonstrated that sRAGE protected against myocardial I/R injury by modulating the differentiation of Tregs through upregulation of the JAK2/STAT3-PD-L1 signaling pathway.

Background: The rostral ventrolateral medulla (RVLM) is a critical vasomotor center that plays a pivotal role in the pathogenesis of hypertension. However, the involvement of circular RNAs (circRNAs) in this nucleus in blood pressure (BP) regulation remains incompletely understood.

Methods: In this study, we investigated functional circRNAs in the RVLM associated with hypertension and elucidated their underlying mechanisms using multiple experimental approaches, including RNA sequencing (RNA-seq), primary cell culture, and intra-RVLM microinjection.

Results: Our results revealed a significantly elevated level of the highly conserved circCdh7 in the RVLM of spontaneously hypertensive rats (SHRs). Downregulation of circCdh7 in the RVLM reduced neuronal excitability, sympathetic outflow, and BP in SHRs. Mechanistically, circCdh7 functioned as a sponge for miR-346. miR-346 knockdown largely abolished the inhibitory effects of circCdh7 suppression on RVLM astrogliosis and neuroinflammation. Furthermore, miR-346 was found to target Osmr. Overexpression of miR-346 attenuated RVLM astrogliosis and neuroinflammation, but these beneficial effects were abolished by Osmr overexpression.

Conclusions: Collectively, our findings demonstrate that elevated circCdh7 expression in the RVLM drives hypertension progression, with the circCdh7/miR-346/Osmr axis serving as a key regulatory mechanism. Targeting circCdh7 may represent a promising therapeutic strategy for hypertension.

Cytokine storm syndrome (CSS) is associated with severe damage and high mortality in acute diseases. Over-activation of M1 macrophages, accompanied with excessive pro-inflammatory cytokine secretion, drives cytokine storms, while promoting M2 macrophage polarization is a potential CSS treatment. The liver, an immune-responsive organ, secretes hepatokines such as fibroblast growth factor-21 (FGF-21) to regulate macrophage activation, but knowledge of their role in CSS-related inflammation is elusive, fueling the search for new hepatokines that can effectively fine-tune the pro-inflammatory activation of macrophages during CSS. In this study, lipopolysaccharide (LPS)-induced CSS signals increase hepatic Angiopoietin-like protein 8 (Angptl8) expression. Angptl8 knockout (Angptl8^-/-) reduces mortality in high-dose LPS-treated mice. This is due to inhibited M1 and enhanced M2 macrophage polarization, decreased pro-inflammatory cytokines, and alleviated CSS symptoms. Angptl8 promotes M1 polarization by activating glycogen metabolism via c-Jun N-terminal kinase (JNK) phosphorylation. Mice treated with an Angptl8-neutralizing antibody have improved CSS symptoms, and the antibody is non-toxic in vivo. Hence, Angptl8 is a promising CSS therapeutic target. Given cytokine storms' role in viral infections and immune therapy-related adverse reactions, targeting Angptl8 may provide new treatments, potentially improving patient outcomes and reducing morbidity and mortality.

Background: T cell homeostasis is crucial for maintaining T cell population size and upcoming protective immunity in the peripheral organs. However, it remains largely unknown about the intracellular molecules and pathways beyond IL-7R signaling. Zfp335, as a key transcription factor, is involved in the multiple-stage development of thymocytes, and effector and memory T cell differentiation during immune responses.

Results: In current study, we found an upregulated expression of ZFP335 in both CD4⁺ and CD8⁺ T cells during peripheral homeostasis. In an adoptive transfer model, Zfp335^-/- T cells failed to undergo homeostatic proliferation without survival defect. Consistently, deletion of Zfp335 impaired T cell proliferation in in vitro culture with IL-7. Furthermore, both RNA-Sequencing and qPCR analysis showed that Zfp335 significantly affected the expression of cell cycle-related genes. Mechanistically, Zfp335 directly binds to the promoter of Lmnb1 gene and regulates its transcription. Overexpression of Lmnb1 significantly rescued the impaired proliferation of Zfp335^-/- T cells.

Conclusion: Our results reveal a previously unrecognized role of Zfp335 in maintaining T cell homeostasis within peripheral lymphoid tissues. Specifically, Zfp335 promotes the homeostatic proliferation of naïve T cells by directly modulating the expression of the Lmnb1 gene which ensuring the capacity of immune system.

Background: Neuroinflammation and apoptosis are important processes of cerebral ischemia-reperfusion injury. USP43 has been shown to play an important role in a variety of cancers, but its function in the field of neuroscience is unclear.

Results: We used an ischemia-reperfusion model of transient embolization of the middle cerebral artery in mice and found that USP43 protein expression was elevated in mice after ischemia-reperfusion injury. Usp43 knockout reduced cerebral infarct volume, inflammatory response, and cell apoptosis, compared to control mice. In vitro, we used an oxygen-glucose-deprived primary neuronal model of rat cortex. Compared with the control group, the Usp43 knockdown group had better cell activity, and the inflammatory response and apoptosis were reduced. Cells in the Usp43 overexpression group exhibited the opposite performance. Mechanistically, we found that USP43 directly interacts with TAK1 by exerting its function as a deubiquitinating enzyme, removing the K48 chain ubiquitination of TAK1 and activating the TAK1-JNK/p38 signaling pathway. Inhibition of USP43 enzyme activity or the use of TAK1 inhibitors can reverse the inflammatory response and neuronal apoptosis induced by USP43 overexpression.

Conclusions: These results suggest that USP43 promotes I-R damage by activating TAK1 and its downstream signaling pathways. Inhibition of USP43 may be a potential treatment modality for acute stroke.

Glucagon-like peptide-1 (GLP-1) is a gut-derived hormone essential for maintaining glucose homeostasis through multiple physiological pathways: triggering insulin release, inhibiting glucagon secretion, delaying gastric emptying, enhancing feelings of fullness, and suppressing appetite. Since GLP-1 is prone to degradation by dipeptidyl peptidase 4, GLP-1 receptor agonists (GLP-1RAs) have been developed to surmount this degradation challenge. At present, GLP-1RAs have become highly effective treatments for managing type 2 diabetes mellitus and obesity. Beyond their well-established benefits for blood sugar regulation and weight control, GLP-1RAs also exhibit various biological activities associated with both insulinotropic effects and immunoregulation. These effects have been demonstrated through in vitro studies, preclinical models, and clinical observations. This review aims to explore the effects of GLP-1R signaling on various immune cells and evaluate the therapeutic potential of GLP-1RAs in autoimmune and autoinflammatory diseases, including psoriasis, inflammatory bowel diseases, rheumatoid arthritis, asthma, multiple sclerosis, Sjögren's syndrome, and systemic lupus erythematosus.