OBJECTIVE: Patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection frequently develop central nervous system damage, yet the mechanisms driving this pathology remain unclear. This study investigated the primary pathways and key factors underlying brain tissue damage induced by the SARS-CoV-2 beta variant (lineage B.1.351). METHODS: K18-hACE2 and C57BL/6 mice were intranasally infected with the SARS-CoV-2 beta variant. Viral replication, pathological phenotypes, and brain transcriptomes were analyzed. Gene Ontology (GO) analysis was performed to identify altered pathways. Expression changes of host genes were verified using reverse transcription-quantitative polymerase chain reaction and Western blot. RESULTS: Pathological alterations were observed in the lungs of both mouse strains. However, only K18-hACE2 mice exhibited elevated viral RNA loads and infectious titers in the brain at 3 days post-infection, accompanied by neuropathological injury and weight loss. GO analysis of infected K18-hACE2 brain tissue revealed significant dysregulation of genes associated with innate immunity and antiviral defense responses, including type I interferons, pro-inflammatory cytokines, Toll-like receptor signaling components, and interferon-stimulated genes. Neuroinflammation was evident, alongside activation of apoptotic and pyroptotic pathways. Furthermore, altered neural cell marker expression suggested viral-induced neuroglial activation, resulting in caspase 4 and lipocalin 2 release and disruption of neuronal molecular networks. CONCLUSION These findings elucidate mechanisms of neuropathogenicity associated with the SARS-CoV-2 beta variant and highlight therapeutic targets to mitigate COVID-19-related neurological dysfunction.
Animals ; COVID-19/genetics* ; Mice ; Brain/metabolism* ; Apoptosis ; Mice, Inbred C57BL ; SARS-CoV-2/physiology* ; Pyroptosis ; Gene Expression Profiling ; Transcriptome ; Male ; Female

Hypoxic-ischemic (HI) brain damage poses a high risk of death or lifelong disability, yet effective treatments remain elusive. Here, we demonstrated that miR-100-5p levels in the lesioned cortex increased after HI insult in neonatal mice. Knockdown of miR-100-5p expression in the brain attenuated brain injury and promoted functional recovery, through inhibiting the cleaved-caspase-3 level, microglia activation, and the release of proinflammation cytokines following HI injury. Engineered extracellular vesicles (EVs) containing neuron-targeting rabies virus glycoprotein (RVG) and miR-100-5p antagonists (RVG-EVs-Antagomir) selectively targeted brain lesions and reduced miR-100-5p levels after intranasal delivery. Both pre- and post-HI administration showed therapeutic benefits. Mechanistically, we identified protein phosphatase 3 catalytic subunit alpha (Ppp3ca) as a novel candidate target gene of miR-100-5p, inhibiting c-Fos expression and neuronal apoptosis following HI insult. In conclusion, our non-invasive method using engineered EVs to deliver miR-100-5p antagomirs to the brain significantly improves functional recovery after HI injury by targeting Ppp3ca to suppress neuronal apoptosis.
Animals ; MicroRNAs/metabolism* ; Extracellular Vesicles/metabolism* ; Mice ; Recovery of Function/physiology* ; Hypoxia-Ischemia, Brain/therapy* ; Mice, Inbred C57BL ; Antagomirs/administration & dosage* ; Male ; Animals, Newborn ; Apoptosis/drug effects* ; Brain Injuries/metabolism* ; Glycoproteins ; Peptide Fragments ; Viral Proteins

OBJECTIVES: Osteoarthritis (OA) is one of the most common chronic degenerative diseases, with chondrocyte apoptosis and extracellular matrix (ECM) degradation as the major pathological changes. The mechanical stimulation can attenuate chondrocyte apoptosis and promote ECM synthesis, but the underlying molecular mechanisms remain unclear. This study aims to investigate the role of primary cilia (PC) in mediating the effects of mechanical stimulation on OA progression. METHODS: In vivo, conditional knockout mice lacking intraflagellar transport 88 (IFT88^flox/flox IFT88 knockout; i.e., primary cilia-deficient mice) were generated, with wild-type mice as controls. OA models were established via anterior cruciate ligament transection combined with destabilization of the medial meniscus, followed by treadmill exercise intervention. OA progression was evaluated by hematoxylin-eosin staining, safranin O-fast green staining, and immunohistochemistry; apoptosis was assessed by TUNEL staining; and limb function by rotarod testing. In vitro, primary articular chondrocytes were isolated from mice and transfected with lentiviral vectors to suppress IFT88 expression, thereby constructing a primary cilia-deficient cell model. Interleukin-1β (IL-1β) was used to induce an inflammatory environment, while cyclic tensile strain (CTS) was applied via a cell stretcher to mimic mechanical loading on chondrocytes. Immunofluorescence and Western blotting were used to detect the protein expression levels of type II collagen α1 chain (COL2A1), primary cilia, IFT88, and caspase-12; reverse transcription polymerase chain reaction was performed to assess COL2A1 mRNA levels; and flow cytometry was used to evaluate apoptosis. RESULTS: In vivo, treadmill exercise significantly reduced Osteoarthritis Research Society International (OARSI) scores and apoptotic cell rates, and improved balance ability in wild-type OA mice, whereas IFT88-deficient OA mice showed no significant improvement. In vitro, CTS inhibited IL-1β-induced ECM degradation and apoptosis in primary chondrocytes; however, this protective effect was abolished in cells with suppressed primary cilia expression. CONCLUSIONS Mechanical stimulation delays OA progression by mediating signal transduction through primary cilia, thereby inhibiting cartilage degeneration and chondrocyte apoptosis.
Animals ; Chondrocytes/cytology* ; Apoptosis/physiology* ; Mice ; Cilia/metabolism* ; Osteoarthritis/pathology* ; Extracellular Matrix/metabolism* ; Mice, Knockout ; Disease Progression ; Interleukin-1beta ; Male ; Cells, Cultured

OBJECTIVES: The neurotoxicity of carbon monoxide (CO) to the central nervous system is a key pathogenesis of delayed encephalopathy after acute carbon monoxide poisoning (DEACMP). Our previous study found that retinoic acid (RA) can suppress the neurotoxic effects of CO. This study further explores, in vivo and in vitro, the molecular mechanisms by which RA alleviates CO-induced central nervous system damage. METHODS: A cytotoxic model was established using the mouse hippocampal neuronal cell line HT22 and primary oligodendrocytes exposed to CO, and a DEACMP animal model was established in adult Kunming mice. Cell viability and apoptosis of hippocampal neurons and oligodendrocytes were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Annexin V/propidium iodide (PI) double staining. The transcriptional and protein expression of each gene was detected using real-time fluorescence quantitative PCR (RT-qPCR) and Western blotting. Long noncoding RNA (lncRNA) SNHG15 and LINGO-1 were knocked down or overexpressed to observe changes in neurons and oligodendrocytes. In DEACMP mice, SNHG15 or LINGO-1 were knocked down to assess changes in central nervous tissue and downstream protein expression. RESULTS: RA at 10 and 20 μmol/L significantly reversed CO-induced apoptosis of hippocampal neurons and oligodendrocytes, downregulation of SNHG15 and LINGO-1, and upregulation of brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) (all P<0.05). Overexpression of SNHG15 or LINGO-1 weakened the protective effect of RA against CO-induced cytotoxicity (all P<0.05). Knockdown of SNHG15 or LINGO-1 alleviated CO-induced apoptosis of hippocampal neurons and oligodendrocytes and upregulated BDNF and TrkB expression levels (all P<0.05). Experiments in DEACMP model mice showed that knockdown of SNHG15 or LINGO-1 mitigated central nervous system injury in DEACMP (all P<0.05). CONCLUSIONS RA alleviates CO-induced apoptosis of hippocampal neurons and oligodendrocytes, thereby reducing central nervous system injury and exerting neuroprotective effects. LncRNA SNHG15 and LINGO-1 are key molecules mediating RA-induced inhibition of neuronal apoptosis and are associated with the BDNF/TrkB pathway. These findings provide a theoretical framework for optimizing the clinical treatment of DEACMP and lay an experimental foundation for elucidating its molecular mechanisms.
Animals ; RNA, Long Noncoding/physiology* ; Brain-Derived Neurotrophic Factor/genetics* ; Carbon Monoxide Poisoning/complications* ; Mice ; Tretinoin/pharmacology* ; Nerve Tissue Proteins/metabolism* ; Membrane Proteins/metabolism* ; Apoptosis/drug effects* ; Hippocampus/cytology* ; Receptor, trkB/metabolism* ; Neurons/drug effects* ; Male ; Brain Diseases/etiology* ; Oligodendroglia/drug effects* ; Signal Transduction ; Cell Line

Non-alcoholic fatty liver disease (NAFLD), including non-alcoholic fatty liver (NAFL), non-alcoholic steatohepatitis (NASH), and advanced fibrosis, is a leading cause of chronic liver disease worldwide, progressing to cirrhosis and ultimately hepatocellular carcinoma (HCC). Excessive accumulation of fatty acids in the liver triggers multiple forms of hepatocyte death and exacerbates NAFLD progression, with pyroptosis and apoptosis considered key events. Recent studies show that cysteine aspartic acid specific protease-3 (caspase-3) is a central regulator of both pyroptosis and apoptosis in NAFLD. Activated caspase-3 not only directly induces apoptosis but also cleaves the N-terminal domain of gasdermin E (GSDME), disrupts cell membranes, releases inflammatory factors, and thereby mediates pyroptosis. Inhibiting caspase-3 expression in NAFLD can alleviate hepatocyte injury (such as ballooning degeneration), dampen pro-inflammatory signaling, and reduce apoptosis. Caspase-3 acts as a key node coordinating pyroptosis and apoptosis and may serve as a novel therapeutic target for the prevention and treatment of NAFLD.
Non-alcoholic Fatty Liver Disease/metabolism* ; Humans ; Pyroptosis/physiology* ; Apoptosis/physiology* ; Caspase 3/physiology* ; Animals ; Gasdermins

OBJECTIVES: To investigate the role and mechanism of fibroblast growth factor (FGF) 19 in inflammation-induced injury of vascular endothelial cells caused by high glucose (HG). METHODS: Human umbilical vein endothelial cells (HUVECs) were randomly divided into four groups: control, HG, FGF19, and HG+FGF19 (n=3 each). The effect of different concentrations of glucose and/or FGF19 on HUVEC viability was assessed using the CCK8 assay. Flow cytometry was utilized to examine the impact of FGF19 on HUVEC apoptosis. Levels of interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), total superoxide dismutase (T-SOD), and malondialdehyde (MDA) were measured by ELISA. Real-time quantitative PCR and Western blotting were used to determine the mRNA and protein expression levels of vascular endothelial growth factor (VEGF), nuclear factor erythroid 2 related factor 2 (Nrf2), and heme oxygenase-1 (HO-1). Cells were further divided into control, siRNA-Nrf2 (siNrf2), HG, HG+FGF19, HG+FGF19+negative control, and HG+FGF19+siNrf2 groups (n=3 each) to observe the effect of FGF19 on oxidative stress injury in HUVECs induced by high glucose after silencing the Nrf2 gene. RESULTS: Compared to the control group, the HG group exhibited increased apoptosis rate, increased IL-6, iNOS and MDA levels, and increased VEGF mRNA and protein expression, along with decreased T-SOD activity and decreased mRNA and protein expression of Nrf2 and HO-1 (P<0.05). Compared to the HG group, the HG+FGF19 group showed reduced apoptosis rate, decreased IL-6, iNOS and MDA levels, and decreased VEGF mRNA and protein expression, with increased T-SOD activity and increased Nrf2 and HO-1 mRNA and protein expression (P<0.05). Compared to the HG+FGF19+negative control group, the HG+FGF19+siNrf2 group had decreased T-SOD activity and increased MDA levels (P<0.05). CONCLUSIONS FGF19 can alleviate inflammation-induced injury in vascular endothelial cells caused by HG, potentially through the Nrf2/HO-1 signaling pathway.
Humans ; NF-E2-Related Factor 2/genetics* ; Signal Transduction ; Human Umbilical Vein Endothelial Cells/drug effects* ; Fibroblast Growth Factors/pharmacology* ; Heme Oxygenase-1/physiology* ; Apoptosis/drug effects* ; Glucose ; Inflammation ; Interleukin-6/analysis* ; Vascular Endothelial Growth Factor A/genetics* ; Nitric Oxide Synthase Type II/analysis* ; Cells, Cultured

Paramyxoviruses are important respiratory pathogens with substantial clinical relevance in pediatric infectious diseases. During infection, multiple forms of programmed cell death (PCD) may be induced, and this plays pivotal roles in viral replication, dissemination, and host immune responses, thereby profoundly influencing the viral life cycle and disease progression. On one hand, PCD facilitates the clearance of infected cells, restricts viral spread, and activates host immune defenses, thereby enhancing antiviral immunity. On the other hand, excessive or dysregulated cell death may lead to tissue damage and immune imbalance, creating a microenvironment conducive to viral replication and exacerbating disease severity. For instance, apoptosis-mediated by both extrinsic and intrinsic pathways-contributes to infection control but may also be hijacked by viruses to promote dissemination. Pyroptosis, driven by inflammasome activation, triggers lytic cell death and the release of pro-inflammatory cytokines. Necroptosis, mediated by the RIPK1-RIPK3-MLKL signaling axis, and pyroptosis both amplify innate immune responses but may concurrently induce inflammatory dysregulation. Immunogenic cell death (ICD), characterized by the release of damage-associated molecular patterns and neoantigens, activates antigen-specific immune responses and holds therapeutic potential for antiviral and antitumor interventions. Emerging evidence suggests that ferroptosis, through the modulation of iron metabolism and associated transporters, may also participate in viral replication and infected cell clearance. This review comprehensively summarizes the roles of apoptosis, pyroptosis, necroptosis, ICD, and ferroptosis in paramyxovirus infection, aiming to deepen the understanding of paramyxovirus pathogenesis and to provide insights for developing novel antiviral strategies.
Humans ; Paramyxoviridae Infections/pathology* ; Pyroptosis ; Apoptosis ; Virus Replication ; Necroptosis ; Inflammasomes ; Immunity, Innate ; Immunogenic Cell Death ; Paramyxoviridae/physiology* ; Signal Transduction

BACKGROUND: The sirtuin family is well recognized for its crucial involvement in various cellular processes. Nevertheless, studies on its role in the human endometrium are limited. This study aimed to explore the expression and localization of the sirtuin family in the human endometrium, focusing on sirtuin 3 (SIRT3) and its potential role in the oxidative imbalance of the endometrium in polycystic ovary syndrome (PCOS). METHODS: Endometrial specimens were collected from both patients with PCOS and controls undergoing hysteroscopy at the Center for Reproductive Medicine, Peking University Third Hospital, from July to August 2015 and used for cell culture. The protective effects of SIRT3 were investigated, and the mechanism of SIRT3 in improving endometrial receptivity of patients with PCOS was determined using various techniques, including cellular bioenergetic analysis, small interfering ribonucleic acid (siRNA) silencing, real-time quantitative polymerase chain reaction, Western blot, immunofluorescence, immunohistochemistry, and flow cytometry analysis. RESULTS: The sirtuin family was widely expressed in the human endometrium, with SIRT3 showing a significant increase in expression in patients with PCOS compared with controls ( P <0.05), as confirmed by protein and gene assays. Concurrently, endometrial antioxidant levels were elevated, while mitochondrial respiratory capacity was reduced, in patients with PCOS ( P <0.05). An endometrial oxidative stress (OS) model revealed that the downregulation of SIRT3 impaired the growth and proliferation status of endometrial cells and reduced their receptivity to day 4 mouse embryos. The results suggested that SIRT3 might be crucial in maintaining normal cellular state by regulating antioxidants, cell proliferation, and apoptosis, thereby contributing to enhanced endometrial receptivity. CONCLUSIONS Our findings proposed a significant role of SIRT3 in improving endometrial receptivity in patients with PCOS by alleviating OS and regulating the balance between cell proliferation and apoptosis. Therefore, SIRT3 could be a promising target for predicting and improving endometrial receptivity in this patient population.
Humans ; Female ; Polycystic Ovary Syndrome/metabolism* ; Endometrium/metabolism* ; Sirtuin 3/genetics* ; Oxidative Stress/genetics* ; Adult ; Animals ; Mice ; Apoptosis/physiology* ; Immunohistochemistry ; Cell Proliferation/physiology*

Lung cancer is one of the most lethal tumors in the world with a 5-year overall survival rate of less than 20%, mainly including lung adenocarcinoma (LUAD). Tumor microenvironment (TME) has become a new research focus in the treatment of lung cancer. The TME is heterogeneous in composition and consists of cellular components, growth factors, proteases, and extracellular matrix. The various cellular components exert a different role in apoptosis, metastasis, or proliferation of lung cancer cells through different pathways, thus contributing to the treatment of adenocarcinoma and potentially facilitating novel therapeutic methods. This review summarizes the research progress on different cellular components with cell-cell interactions in the TME of LUAD, along with their corresponding drug candidates, suggesting that targeting cellular components in the TME of LUAD holds great promise for future theraputic development.
Humans ; Tumor Microenvironment/drug effects* ; Adenocarcinoma of Lung/drug therapy* ; Lung Neoplasms/pathology* ; Adenocarcinoma/metabolism* ; Animals ; Apoptosis/physiology*

BACKGROUND: Pancreatic cancer is a lethal malignancy prone to gemcitabine resistance. The single-strand selective monofunctional uracil DNA glycosylase (SMUG1), which is responsible for initiating base excision repair, has been reported to predict the outcomes of different cancer types. However, the function of SMUG1 in pancreatic cancer is still unclear. METHODS: Gene and protein expression of SMUG1 as well as survival outcomes were assessed by bioinformatic analysis and verified in a cohort from Fudan University Shanghai Cancer Center. Subsequently, the effect of SMUG1 on proliferation, cell cycle, and migration abilities of SMUG1 cells were detected in vitro . DNA damage repair, apoptosis, and gemcitabine resistance were also tested. RNA sequencing was performed to determine the differentially expressed genes and signaling pathways, followed by quantitative real-time polymerase chain reaction and Western blotting verification. The cancer-promoting effect of forkhead box Q1 (FOXQ1) and SMUG1 on the ubiquitylation of myelocytomatosis oncogene (c-Myc) was also evaluated. Finally, a xenograft model was established to verify the results. RESULTS: SMUG1 was highly expressed in pancreatic tumor tissues and cells, which also predicted a poor prognosis. Downregulation of SMUG1 inhibited the proliferation, G1 to S transition, migration, and DNA damage repair ability against gemcitabine in pancreatic cancer cells. SMUG1 exerted its function by binding with FOXQ1 to activate the Protein Kinase B (AKT)/p21 and p27 pathway. Moreover, SMUG1 also stabilized the c-Myc protein via AKT signaling in pancreatic cancer cells. CONCLUSIONS SMUG1 promotes proliferation, migration, gemcitabine resistance, and c-Myc protein stability in pancreatic cancer via protein kinase B signaling through binding with FOXQ1. Furthermore, SMUG1 may be a new potential prognostic and gemcitabine resistance predictor in pancreatic ductal adenocarcinoma.
Humans ; Pancreatic Neoplasms/pathology* ; Forkhead Transcription Factors/genetics* ; Signal Transduction/genetics* ; Animals ; Cell Line, Tumor ; Proto-Oncogene Proteins c-akt/metabolism* ; Cell Proliferation/physiology* ; Mice ; Uracil-DNA Glycosidase/genetics* ; Female ; Male ; Gemcitabine ; Mice, Nude ; Apoptosis/physiology* ; Deoxycytidine/analogs & derivatives* ; Cell Movement/genetics*