The FASEB Journal最新文献

Lung bacterial infections, including hospital-acquired pneumonia, remain a serious problem for public health. Endothelial cell (EC) exposure to heat-killed Staphylococcus aureus (HKSA) represents a clinical scenario of high titers of killed bacterial particles present in the host after antibiotic therapy, which triggers inflammatory cascades, cytokine storms, and EC dysfunction leading to acute lung injury (ALI). GPR68 is a member of the proton-sensing G protein-coupled receptor family. Acting as a pH sensor, GPR68 becomes activated upon pH reduction and contributes to pathologic cell responses by activating ER stress and unfolded protein response. This study investigated the role of GPR68 in HKSA-induced EC dysfunction and HKSA-induced ALI. HKSA robustly increased GPR68 mRNA levels in human pulmonary EC and directly stimulated GPR68 activity. A selective GPR68 small molecule inhibitor, OGM-8345, attenuated HKSA-induced EC permeability and protected cell junction integrity. OGM-8345 inhibited HKSA-induced activation of inflammatory genes TNF-α, IL-6, IL-8, IL-1β, and CXCL5 and decreased cytokine secretion by HKSA-challenged EC. Co-treatment with the GPR68 activator Ogerin or medium acidification to pH 6.5 augmented HKSA-induced EC dysfunction, which was rescued by OGM-8345. Intratracheal HKSA injection increased vascular leak and lung inflammation in mice which were monitored by lung Evans blue extravasation, increased cell and protein count in bronchoalveolar lavage, and mRNA expression of inflammatory genes. ALI and barrier dysfunction was attenuated by OGM-8345. We show for the first time the role of GPR68 in mediating HKSA-induced lung injury and the strong potential for OGM-8345 as a therapeutic treatment of bacterial pathogen-induced ALI associated with tissue acidification.

Glucagon-like peptide-1 (GLP-1), derived from enteroendocrine cells, is a pivotal hormone crucial for blood glucose regulation. Menin, encoded by the MEN1 gene and known for its tumor suppressor role, is abundantly expressed in the intestine. Previous research has demonstrated that acute Men1 excision reverses preexisting glucose intolerance in high-fat diet-fed mice. However, its impact on GLP-1 expression in enteroendocrine cells has not been investigated. In the present study, both the knockdown of Men1 and the administration of the MI-463 menin inhibitor increased GLP-1 expression in glucose-stimulated STC-1 cells. Additionally, administering MI-463 to obese mice significantly elevated GLP-1 levels in both ileal epithelial cells and serum. Mechanistically, menin inhibition enhanced the nuclear accumulation of β-catenin, allowing it to bind TCF7L2, thereby increasing glucagon gene (Gcg) transcription. Furthermore, compared with control mice, mice with intestinal epithelial cell-specific Men1 knockdown exhibited significant improvements in glucose tolerance under fat challenge, which was correlated with elevated GLP-1 levels. These findings suggest that menin-mediated regulation of GLP-1 expression may be an important mechanism through which menin inhibiton alleviates type 2 diabetes.

Intestinal epithelial cells (IECs) are dynamically regulated by luminal contents, including dietary ingredients, food additives, and microbiota-derived metabolites. Although sugar substitutes are commonly used as food additives for their sweet taste and lower calorie content, there is limited experimental evidence regarding their potential to drive gut remodeling. In this study, we designed experimental models for short-term consumption of erythritol, a natural sugar alcohol widely used as a sugar substitute, and investigated its effects on gut remodeling and the underlying mechanisms. Our findings indicate that erythritol consumption induces hyperplasia in tuft cells (TCs) and goblet cells (GCs), as well as enhances the activity of intestinal stem cells–increases in expression levels of leucine-rich repeat containing G protein-coupled receptor 5 (Lgr5), the key intestinal stem cell marker, in the number of proliferating stem cells, and facilitation of their differentiation into villi cells–while maintaining the number of Lgr5⁺ intestinal stem cells. Notably, the enhanced stem cell activity was observed even in Trpm5 knockout mice, suggesting that it is mechanistically independent of TC hyperplasia. Instead, we demonstrated the functional involvement of the gut microbiota, as antibiotic treatment abolished this effect, and fecal material transfer from erythritol-consumed mice replicated the enhancement of stem cell activity in recipient mice. Furthermore, we identified acetate as the metabolite responsible for enhancing stem cell activity. These findings suggest the functional decoupling of TC hyperplasia and the enhancement of stem cell activity, providing a potential therapeutic avenue for gut epithelial diseases.

Harbinger transposase-derived 1 proteins (HARBI1s) play important roles in plant growth, development, and response to abiotic stress. OsHARBI1-1 has been identified as a gene encoding HARBI1-1 protein in rice and has been shown to be responsive to Cadmium (Cd) stress. However, the function of OsHARBI1-1 protein under heavy metal stress remains unclear. In this study, the function of a novel rice Cd-responsive gene, OsHARBI1-1, under Cd stress was characterized by heterologous expression in yeast. The heterologous expression OsHARBI1-1 conferred yeast with increased tolerance to Cd. In addition, the yeast cells expressing OsHARBI1-1 exhibited enhanced tolerance to Congo red and exhibited an increase in cell wall thickness under Cd stress, suggesting a potential correlation between increased Cd tolerance and cell wall thickness in the transgenic yeast. When OsHARBI1-1 was expressed in ∆yap1 or ∆yap1∆ycf1 yeast mutants, there was no significant difference in the tolerance of transgenic yeast to Cd and Congo red, as well as in cell wall thickness compared to the control. Meanwhile, the expression of cell wall integrity (CWI) genes and catalase genes in transgenic yeast was up-regulated in a YAP1-dependent manner under Cd or Congo red stress. The above facts supported the inference that OsHARBI1-1 may counteract Cd toxicity by enhancing the expression of YAP1, thereby increasing the thickness of the cell wall and activating the expression of catalase genes.

Retinal neovascularization impairs visual function and is a hallmark of several neovascular eye diseases, including retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (PDR). Current treatments include intravitreal injections of anti-vascular endothelial growth factor (VEGF) biologics, but these therapeutics are often accompanied by high treatment burden and resistance to therapy. Prior studies indicate that APE1/Ref-1, a multifunctional protein with both endonuclease (APE1) and redox-mediated transcriptional regulatory activity (Ref-1), activates multiple pro-angiogenic and pro-inflammatory signaling pathways by chemically reducing key cysteine residues in transcription factors, thereby activating them. Here, we investigated the previously unexplored role of Ref-1 in retinal neovascularization. We demonstrate that Ref-1 is highly expressed in endothelial cells in human PDR and in the oxygen-induced retinopathy (OIR) mouse model of retinal neovascularization. Ref-1 is also highly expressed in microglia and astrocytes in OIR. A small molecule Ref-1 redox inhibitor, APX2009, decreased retinal neovascularization in OIR after systemic delivery. In vitro, hypoxic endothelial cells did not exhibit upregulation of Ref-1 but rather increased Ref-1 nuclear localization. APX2009 decreased hypoxic endothelial cell proliferation and HIF-1α transcriptional activation. Thus, Ref-1 redox activity may be a novel therapeutic target for the treatment of retinal neovascularization, making APX2009 a promising systemic therapeutic approach for the treatment of vascular retinopathies such as ROP and PDR.

Exercise impinges on almost all physiological processes at an organismal level and is a potent intervention to treat various diseases. Exercise performance is well established to display diurnal rhythm, peaking during the late active phase. However, the underlying molecular/metabolic factors and mitochondrial energetics that possibly dictate time-of-day exercise capacity remain unknown. Here, we have unraveled the importance of diurnal variation in mitochondrial functions as a determinant of skeletal muscle exercise performance. Our results show that exercise-induced muscle metabolome and mitochondrial energetics are distinct at ZT3 and ZT15. Importantly, we have elucidated key diurnal differences in mitochondrial functions that are well correlated with disparate time-of-day-dependent exercise capacity. Providing causal mechanistic evidence, we illustrate that loss of Sirtuin4 (SIRT4), a well-known mitochondrial regulator, abrogates mitochondrial diurnal variation and consequently abolishes time-of-day-dependent muscle output. Therefore, our findings unequivocally demonstrate the pivotal role of baseline skeletal muscle mitochondrial functions in dictating diurnal exercise capacity.

Microglial activation and pyroptosis are central to neuroinflammation and significantly contribute to cognitive decline associated with neurodegenerative diseases. Alpha protein kinase 1 (ALPK1) is recently identified as a critical mediator of inflammatory responses in response to ADP-heptose (a pathogen-associated molecular pattern). However, its specific role in microglial pyroptosis and cognitive dysfunction remains unclear. In this study, we investigated the effects of ALPK1 on cognitive function and pyroptosis in wild-type (WT) and ALPK1 KO mice by intracerebroventricular administration of ADP-heptose to induce neuroinflammation. Cognitive performance was evaluated using behavioral tests (the Y-Maze, Morris Water Maze, and step-down passive avoidance), while Western blot, immunofluorescence, transmission electron microscopy, and enzyme-linked immunosorbent assay were used to evaluate the expression of pyroptosis markers such as NLRP3, Caspase-1, and gasdermin D (GSDMD) in vivo and in vitro. Our results reveal that the absence of ALPK1 significantly attenuated ADP-heptose-induced cognitive deficits and neuronal injury, and inhibited the NLRP3/Caspase-1/GSDMD pathway of pyroptosis and the secretion of pro-inflammatory cytokines IL-1β and IL-18. Notably, ADP-heptose-stimulated conditioned media from primary microglial cells of ALPK1 KO mice significantly enhanced neuronal cell viability, suggesting a protective role for ALPK1 deficiency in supporting neuronal health. These findings suggest the pivotal role of ALPK1 in ADP-heptose-induced microglial pyroptosis and cognitive impairment, thereby highlighting its potential as a therapeutic target in neuroinflammatory disorders.

Renal ischemia–reperfusion injury (IRI) is a prevalent cause of acute kidney injury, however, the regulatory mechanisms of miR-374b-5p in renal IRI remain poorly understood. We established hypoxia/reoxidation (H/R)-induced renal injury models using HK-2 and TCMK-1 cells, as well as an ischemia–reperfusion (I/R)-induced mouse model. Renal tubular epithelial cells (RTECs) viability and apoptosis were assessed using CCK-8, flow cytometry, and TUNEL assays. The targeting relationship between miR-374b-5p and SRSF7 was analyzed using dual luciferase reporter assays. The interaction between METTL3 and miR-374b-5p was confirmed through methylated RNA immunoprecipitation (MeRIP) and co-immunoprecipitation (Co-IP) assays. We found that miR-374b-5p levels were significantly upregulated in H/R-induced HK-2 and TCMK-1 cells. Furthermore, miR-374b-5p promoted H/R-induced RTEC injury by suppressing cell viability and exacerbating apoptosis. SRSF7 was identified as a downstream target of miR-374b-5p, inhibition of SRSF7 reversed the inhibitory effects of miR-374b-5p inhibitors on RTEC injury. Additionally, METTL3 interacted with the microprocessor protein DGCR8 and modulated the processing of pri-miR-374b-5p in an m6A-dependent manner. In the renal IRI model, METTL3 and miR-374b-5p levels were upregulated, and knockdown of METTL3 inhibited apoptosis in H/R-induced HK-2 and TCMK-1 cells. Conversely, miR-374b-5p reversed the protective effects of METTL3 knockdown on renal IRI. Our findings provide novel insights into the role of m6A methylation in the development of renal IRI, demonstrating that METTL3 promotes renal IRI by modulating the miR-374b-5p/SRSF7 axis.

Discrimination is a social adversity that is linked to several age-related outcomes. However, the molecular drivers of these observations are poorly understood. Social adverse factors are associated with proinflammatory and interferon gene expression, but little is known about whether additional genes are associated with discrimination among both African American and White adults. In this study, we examined how perceived discrimination in African American and White adults was associated with genome-wide transcriptome differences using RNA sequencing. Perceived discrimination was measured based on responses to self-reported lifetime discrimination and racial discrimination. Differential gene expression and pathway analysis were conducted in a cohort (N = 59) stratified by race, sex, and overall discrimination level. We found 28 significantly differentially expressed genes associated with race among those reporting high discrimination. Several of the upregulated genes for African American versus White adults reporting discrimination were related to immune function IGLV2-11, S100B, IGKV3-20, and IGKV4-1; the most significantly downregulated genes were associated with immune modulation and cancer, LUCAT1, THBS1, and ARPIN. The most enriched gene ontology biological process between African American and White men reporting high discrimination was the regulation of cytokine biosynthetic processes. The immune response biological process was significantly lower for African American women compared to White women reporting high discrimination. Discrimination was associated with the expression of small nucleolar RNAs, long noncoding RNAs, and microRNAs associated with energy homeostasis, cancer, and actin. Understanding the pathways through which adverse social factors like discrimination are associated with gene expression is crucial in advancing knowledge of age-related health disparities.

Junjie, Zhu,Peng, Chen,Jiaojiao, Liang et al. Inhibition of CK2α accelerates skin wound healing by promoting endothelial cell proliferation through the Hedgehog signaling pathway. FASEB J. 2023;37:e23135.

Affiliation Section: the affiliation of one of the authors, Junjie Zhu is incorrect.

The correct affiliation for Junjie Zhu is as follows: “Department of Cardiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, P.R. China.”

Correct author list: Junjie Zhu^1,2, Peng Chen¹, Jiaojiao Liang⁴, Zhaohang Wu², Haiqun Jin⁵, Tianpeng Xu², Yeyi Zheng², Hongfang Ma², Weitao Cong^2,3, Xu Wang², Xueqiang Guan¹

We apologize for this error.