FASEB Journal最新文献

Traumatic brain injury (TBI), which is characterized by acute neurological dysfunction, is also one of the most widely recognized environmental risk factors for various neurological and psychiatric disorders. However, the role of TBI in neurological perturbation and the mechanisms underlying these disorders remain unknown. We evaluated transcriptional changes in cells of the frontal cortex after TBI by exploiting single-cell RNA sequencing (scRNA-Seq). We adopted the gene expression omnibus and scRNA-Seq to identify the mediation by secretogranin II (SCG2) of TBI-induced schizophrenia. Astrocytes are a principal source of SCG2 in the frontal cortex after TBI. Our analysis indicated that SCG2-triggered disruption of the blood–brain barrier (BBB) via the CypA-MMP-9 signaling pathway. Furthermore, astrocytic SCG2 knockout in the frontal cortex reduced BBB damage, mitigated inflammation, and inhibited schizophrenia after TBI. In conclusion, we identified the SCG2-CypA-MMP-9 signaling pathway in reactive astrocytes as a key switch in the protection of the BBB and provided a novel therapeutic avenue for treating psychiatric disorders after TBI.

The human retinal pigment epithelium (RPE) cell line ARPE-19 is widely used as an alternative to primary RPE despite losing many features of primary RPE. We aimed to determine whether a combination of RPE-specific laminin (LN) and nicotinamide (NAM) could improve ARPE-19 redifferentiation to resemble mature RPE and improve the assessment of RPE-specific gene therapy strategies. ARPE-19 cells were propagated on tissue culture plastic supplemented with NAM and human recombinant LN521-coating. RPE maturation was performed by immunocytochemistry and gene expression by qPCR. Viral transduction experiments with adeno-associated virus (AAV)1 or AAV2, carrying a VMD2-driven GFP, were assessed at 2- and 4-weeks post-plating in the different culturing conditions with a low multiplicity of infection. The combination of LN521 coating with NAM supplementation promoted cytoskeletal and tight junction protein reorganization. The expression of maturation markers bestrophin-1 and RPE 65 was promoted concomitantly with a reduction of several epithelial-mesenchymal transition markers, such as TNF-α, TGF-β, CDH2, and vimentin. Redifferentiated ARPE-19 transduced at low multiplicity of infection of both AAV1- and AAV2-VMD2-GFP. Expression of GFP was detected at 2 weeks and increased at 4 weeks post-plating. AAV1 exhibited a greater expression efficacy compared to AAV2 in maturated ARPE-19 cells already after 2 weeks with increased efficiency after 4 weeks. Our study demonstrates an improved maturation protocol for ARPE-19 cells in vitro, mimicking an in vivo phenotype with the expression of signature genes and improved morphology. Viral-mediated RPE-specific gene expression demonstrates that the combination cultures mimic in vivo AAV tropism essential to test new gene therapies for RPE-centered diseases.

The complex pathogenesis of lung ischemia–reperfusion injury (LIRI) was examined in a murine model, focusing on the role of pyroptosis and its exacerbation of lung injury. We specifically examined the levels and cellular localization of pyroptosis within the lung, which revealed alveolar macrophages as the primary site. The inhibition of pyroptosis by VX-765 reduced the severity of lung injury, underscoring its significant role in LIRI. Furthermore, the therapeutic potential of β-hydroxybutyrate (β-OHB) in ameliorating LIRI was examined. Modulation of β-OHB levels was evaluated by ketone ester supplementation and 3-hydroxybutyrate dehydrogenase 1 (BDH-1) gene knockout, along with the manipulation of the SIRT1-FOXO3 signaling pathway using EX-527 and pCMV-SIRT1 plasmid transfection. This revealed that β-OHB exerts lung-protective and anti-pyroptotic effects, which were mediated through the upregulation of SIRT1 and the enhancement of FOXO3 deacetylation, leading to decreased pyroptosis markers and lung injury. In addition, β-OHB treatment of MH-S cells in vitro showed a concentration-dependent improvement in pyroptosis, linking its therapeutic benefits to specific cell mechanisms. Overall, this study highlights the significance of alveolar macrophage pyroptosis in the exacerbation of LIRI and indicates the potential of β-OHB in mitigating injury by modulating the SIRT1-FOXO3 signaling pathway.

Citicoline, a compound produced naturally in small amounts in the human body, assumes a pivotal role in phosphatidylcholine synthesis, a dynamic constituent of membranes of neurons. Across diverse models of brain injury and neurodegeneration, citicoline has demonstrated its potential through neuroprotective and anti-inflammatory effects. This review aims to elucidate citicoline's anti-inflammatory mechanism and its clinical implications in conditions such as ischemic stroke, head trauma, glaucoma, and age-associated memory impairment. Citicoline's anti-inflammatory prowess is rooted in its ability to stabilize cellular membranes, thereby curbing the excessive release of glutamate—a pro-inflammatory neurotransmitter. Moreover, it actively diminishes free radicals and inflammatory cytokines productions, which could otherwise harm neurons and incite neuroinflammation. It also exhibits the potential to modulate microglia activity, the brain's resident immune cells, and hinder the activation of NF-κB, a transcription factor governing inflammatory genes. Clinical trials have subjected citicoline to rigorous scrutiny in patients grappling with acute ischemic stroke, head trauma, glaucoma, and age-related memory impairment. While findings from these trials are mixed, numerous studies suggest that citicoline could confer improvements in neurological function, disability reduction, expedited recovery, and cognitive decline prevention within these cohorts. Additionally, citicoline boasts a favorable safety profile and high tolerability. In summary, citicoline stands as a promising agent, wielding both neuroprotective and anti-inflammatory potential across a spectrum of neurological conditions. However, further research is imperative to delineate the optimal dosage, treatment duration, and underlying mechanisms. Moreover, identifying specific patient subgroups most likely to reap the benefits of citicoline as a new therapy remains a critical avenue for exploration.

Cone photoreceptor cyclic nucleotide-gated (CNG) channels play an essential role in phototransduction and cellular Ca²⁺ homeostasis. Mutations in genes encoding the channel subunits CNGA3 and CNGB3 are associated with achromatopsia, progressive cone dystrophy, and early-onset macular degeneration. Cone loss in patients with achromatopsia and cone dystrophy associated with CNG channel mutations has been documented by optical coherence tomography and in mouse models of CNG channel deficiency. Cone death in CNG channel-deficient retinas involves endoplasmic reticulum (ER) stress-associated apoptosis, dysregulation of cellular/ER Ca²⁺ homeostasis, impaired protein folding/processing, and impaired ER-associated degradation (ERAD). The E3 ubiquitin-protein ligase synoviolin 1 (SYVN1) is the primary component of the SYVN1/SEL1L ER retrotranslocon responsible for ERAD. Previous studies have shown that manipulations that protect cones and reduce ER stress/cone death in CNG channel deficiency, such as increasing ER Ca²⁺ preservation or treatment with an ER chaperone, increase the expression of SYVN1 and other components of the ER retrotranslocon. The present work investigated the effects of SYVN1 overexpression. Intraocular injection of AAV5-IRBP/GNAT2-Syvn1 resulted in overexpression of SYVN1 in cones of CNG channel-deficient mice. Following treatment, cone density in Cnga3^−/− mice was significantly increased, compared with untreated controls, outer segment localization of cone opsin was improved, and ER stress/apoptotic cell death was reduced. Overexpression of SYVN1 also led to increased expression levels of the retrotranslocon components, degradation in ER protein 1 (DERL1), ERAD E3 ligase adaptor subunit (SEL1L), and homocysteine inducible ER protein with ubiquitin-like domain 1 (HERPUD1). Moreover, overexpression of SYVN1 likely enhanced protein ubiquitination/proteasome degradation in CNG channel-deficient retinas. This study demonstrates the role of SYVN1/ERAD in cone preservation in CNG channel deficiency and supports the strategy of promoting ERAD for cone protection.

Immunotherapies have significantly improved the prognosis of patients with advanced hepatocellular carcinoma (HCC), although more than 70% of patients still do not respond to this first-line treatment. Many new combination strategies are currently being explored, which drastically increases the need for preclinical models that would allow large-scale testing of new immunotherapies and their combinations. We developed several in ovo (in the egg) human liver cancer models, based on human tumor xenografts of different liver cancer cell lines on the chicken embryo's chorioallantoic membrane. We characterized the angiogenesis, as well as the collagen accumulation and tumor immune microenvironment, and tested atezolizumab (anti-PD-L1) plus bevacizumab (anti-VEGF) treatment. Our results show the involvement of chicken immune cells in tumor growth, reproducing a classical non-inflamed “cold” as well as inflamed “hot” tumor status, depending on the in ovo liver cancer model. The treatment by atezolizumab and bevacizumab was highly efficient in the “hot” tumor model PLC/PRF/5 in ovo with the reduction of tumor size by 76% (p ≤ .0001) compared with the control, whereas the efficacy was limited in the “cold” Hep3B in ovo tumor. The contribution of the anti-PD-L1 blockade to the anti-tumoral effect in the PLC/PRF/5 in ovo model was demonstrated by the efficacy of atezolizumab monotherapy (p = .0080, compared with the control). To conclude, our study provides a detailed characterization and rational arguments that could help to partially replace conventional laboratory animals with a more ethical model, suited to the current needs of preclinical research of new immunotherapies for liver cancer.

Macrophages have been recognized as pivotal players in the progression of MASLD/MASH. However, the molecular mechanisms underlying their multifaceted functions in the disease remain to be further clarified. In the current study, we developed a new mouse model with YAP activation in macrophages to delineate the effect and mechanism of YAP signaling in the pathogenesis of MASLD/MASH. Genetically modified mice, featuring specific depletion of both Mst1 and Mst2 in macrophages/monocytes, were generated and exposed to a high-fat diet for 12 weeks to induce MASLD. Following this period, livers were collected for histopathological examination, and liver non-parenchymal cells were isolated and subjected to various analyses, including single-cell RNA-sequencing, immunofluorescence and immunoblotting and qRT-PCR to investigate the impact of YAP signaling on the progression of MASLD. Our data revealed that Mst1/2 depletion in liver macrophages enhanced liver inflammation and fibrosis in MASLD. Using single-cell RNA-sequencing, we showed that YAP activation via Mst1/2 depletion upregulated the expressions of both pro-inflammatory genes and genes associated with resolution/tissue repair. We observed that YAP activation increases Kupffer cell populations (i.e., Kupffer-2 and Kupffer-3) which are importantly implicated in the pathogenesis of MASLD/MASH. Our data indicate that YAP activation via Mst1/2 deletion enhances both the pro-inflammatory and tissue repairing functions of Kupffer-1 and -2 cells at least in part through C1q. These YAP-regulatory mechanisms control the plasticity of liver macrophages in the context of MASLD/MASH. Our findings provide important evidence supporting the critical regulatory role of YAP signaling in liver macrophage plasticity and the progression of MASLD. Therefore, targeting the Hippo-YAP pathway may present a promising therapeutic strategy for the treatment of MASH.

Non-proliferative diabetic retinopathy (NPDR) is the early stage of diabetic retinopathy (DR) and is a chronic oxidative stress-related ocular disease. Few treatments are approved for early DR. This study aimed to investigate the pathogenic mechanisms underlying the retinal micro-vasculopathy induced by diabetes and to explore an early potential for treating early DR in a mouse model. The mouse model of type 1 diabetes was established by intraperitoneal injection of streptozotocin (STZ, 180 mg/kg), which was used as the early DR model. The body weight and blood glucose mice were measured regularly; The retinal vascular leakage in the early DR mice was determined by whole-mount staining; Label-free quantitative proteomic analysis and bioinformatics were used to explore the target proteins and signaling pathways associated with the retinal tissues of early DR mice; To detect the effects of target protein on endothelial cell proliferation, migration, and tube formation, knockdown and overexpression of VEGF-B were performed in human retinal vascular endothelial cells (HRECs); Western blotting was used to detect the expression of target proteins in vitro and in vivo; Meanwhile, the therapeutic effect of VEGF-B on vascular leakage has also been evaluated in vitro and in vivo. The protein expressions of vascular endothelial growth factor (VEGF)-B and the Rho GTPases family member CDC42 were reduced in the retinal tissues of early DR. VEGF-B upregulated the expression of CDC42/ZO1/VE-cadherin and prevented hyperglycemia-induced vascular leakage in HRECs. Standard intravitreal VEGF-B injections improved the retinal vascular leakage and neurovascular response in early DR mice. Our findings demonstrated, for the first time, that in diabetes, the retinal vessels are damaged due to decreased VEGF-B expression through downregulation of CDC42/ZO1/VE-cadherin expression. Therefore, VEGF-B could be used as a novel therapy for early DR.

Prenatal multivitamins, including folic acid, are commonly consumed in excess, whereas choline, an essential nutrient and an important source of labile methyl groups, is underconsumed. Here, we characterized profiles of one-carbon metabolism and related pathways and patterns of DNA methylation in offspring exposed to excess or imbalanced micronutrients prenatally. Pregnant Wistar rats were fed either recommended 1× vitamins (RV), high 10× vitamins (HV), high 10× folic acid with recommended choline (HFolRC), or high 10× folic acid with no choline (HFolNC). Offspring were weaned to a high-fat diet for 12 weeks. Circulating metabolites were analyzed with a focus on the hypothalamus, an area known to be under epigenetic regulation. HV, HFolRC, and HFolNC males had higher body weight (BW) and lower plasma choline and methionine consistent with lower hypothalamic S-adenosylmethionine (SAM):S-adenosylhomocysteine (SAH) and global DNA methylation compared with RV. HV and HFolNC females had higher BW and lower plasma 5-methyltetrahydrofolate and methionine consistent with lower hypothalamic global DNA methylation compared with RV. Plasma dimethylglycine (DMG) and methionine were higher as with hypothalamic SAM:SAH and global DNA methylation in HFolRC females without changes in BW compared with RV. Plasma trimethylamine and trimethylamine-N-oxide were higher in males but lower in females from HFolRC compared with RV. Network modeling revealed a link between the folate-dependent pathway and SAH, with most connections through DMG. Final BW was negatively correlated with choline, DMG, and global DNA methylation. In conclusion, prenatal intake of excess or imbalanced micronutrients induces distinct metabolic and epigenetic perturbations in offspring that reflect long-term nutritional programming of health.