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Cellular Inflammation-Induced Cleavage of Phosphorothioate DNA Locker Activates CRISPR/Cas9 Regulator for Gene Editing.

The CRISPR technology is a highly promising strategy for developing a versatile toolbox to engineer genetic circuits. However, achieving precise and specific control over the activity of the CRISPR/Cas9 system in response to intracellular processes remains a challenging endeavor. In this study, we present a cellular inflammation-induced activation of an engineered CRISPR/Cas9 regulator for gene regulation. A phosphorothioate (PS)-modified DNA sequence, referred as the "locker," is employed to deactivate single guide RNA (sgRNA), whose locker sequence complements the spacer region of sgRNA. In the presence of myeloperoxidase during cellular inflammation, a halogenation process is triggered, leading to the generation of HClO, specifically cleaving the PS site of locker and activating CRISPR/Cas9 for gene editing. The target GFP gene has been successfully edited, downregulating the GFP protein expression in HeLa cells. This study provides valuable insights into the CRISPR-based gene regulation through specific endogenous processes.

Humans

Mechanotransduction in musculoskeletal mesenchymal tissues: implications for bone, tendon, and cartilage regenerative engineering-a narrative review.

PURPOSE/AIM OF THE STUDY: To integrate evidence on how mechanical signals regulate musculoskeletal connective-tissue biology and how cellular context and loading history shape mechanotransduction and mechanical memory. MATERIALS AND METHODS: This narrative review synthesized PubMed-indexed evidence on extracellular matrix mechanics, adhesion complexes, the cytoskeleton, nucleus, primary cilia, mechanosensitive ion channels, cell state, and loading history in bone, tendon, ligament, and cartilage. RESULTS: Mechanotransduction is best understood as a coupled extracellular matrix-integrin-cytoskeleton-nucleus continuum rather than as independent cytoskeletal or nuclear drivers. Responses are conditioned by lineage stage, anatomic niche, inflammation, cellular subpopulation, and prior mechanical exposure. Mechanical memory may be encoded through persistent YAP/TAZ activity, microRNA programs, DNA methylation, histone modifications, chromatin architecture, and metabolic remodeling. Evidence is strongest for bone, including Piezo-dependent osteogenesis, TRPV4-mediated shear sensing, viscoelastic compression, osteocyte-stromal extracellular-vesicle signaling, and osteogenesis-angiogenesis coupling. Tendon and ligament require anisotropic architecture and strain-window control, whereas cartilage shows a narrow distinction between physiologic TRPV4-associated anabolism and high-strain or inflammation-sensitized Piezo/YAP-mediated maladaptation. CONCLUSIONS: Translational implications include mechanically defined cell expansion, biomaterial preconditioning, stage-specific rehabilitation, and potency assays incorporating loading history. Direct clinical validation of stable perioperative cellular mechanical memory remains limited. Future studies should combine controlled mechanical perturbation with bulk and single-cell RNA sequencing, chromatin-accessibility profiling, spatial methods, and perturbational genomics.

Mechanotransduction

Retinal Proteome Profiling of Inherited Retinal Degeneration Across Three Different Mouse Models Suggests Common Drug Targets in Retinitis Pigmentosa.

Inherited retinal degenerations (IRDs) are a leading cause of blindness among the population of young people in the developed world. Approximately half of IRDs initially manifest as gradual loss of night vision and visual fields, characteristic of retinitis pigmentosa (RP). Due to challenges in genetic testing, and the large heterogeneity of mutations underlying RP, targeted gene therapies are an impractical largescale solution in the foreseeable future. For this reason, identifying key pathophysiological pathways in IRDs that could be targets for mutation-agnostic and disease-modifying therapies (DMTs) is warranted. In this study, we investigated the retinal proteome of three distinct IRD mouse models, in comparison to sex- and age-matched wild-type mice. Specifically, we used the Pde6βRd10 (rd10) and RhoP23H/WT (P23H) mouse models of autosomal recessive and autosomal dominant RP, respectively, as well as the Rpe65-/- mouse model of Leber's congenital amaurosis type 2 (LCA2). The mice were housed at two distinct institutions and analyzed using LC-MS in three separate facilities/instruments following data-dependent and data-independent acquisition modes. This cross-institutional and multi-methodological approach signifies the reliability and reproducibility of the results. The large-scale profiling of the retinal proteome, coupled with in vivo electroretinography recordings, provided us with a reliable basis for comparing the disease phenotypes and severity. Despite evident inflammation, cellular stress, and downscaled phototransduction observed consistently across all three models, the underlying pathologies of RP and LCA2 displayed many differences, sharing only four general KEGG pathways. The opposite is true for the two RP models in which we identify remarkable convergence in proteomic phenotype even though the mechanism of primary rod death in rd10 and P23H mice is different. Our data highlights the cAMP and cGMP second-messenger signaling pathways as potential targets for therapeutic intervention. The proteomic data is curated and made publicly available, facilitating the discovery of universal therapeutic targets for RP.

Animals

Genome-wide association study of sarcopenia index reveals sex-stratified genetic architecture.

BACKGROUND: The sarcopenia index (SI), defined as the ratio of serum creatinine to cystatin C, is a proposed biomarker of muscle mass and sarcopenia, yet its genomic basis and genetic architecture remain largely unexplored. METHODS: We performed combined-sex and sex-stratified genome-wide association studies of SI in the UK Biobank. We examined the overlap between SI-associated loci and loci previously reported for sarcopenia-related traits. We assessed sexually dimorphic effects and gene-sex interactions, performed fine-mapping, and conducted credible gene prioritization, motif and transcription factor binding enrichment, gene-set enrichment, linkage disequilibrium score regression, and cross-phenotype colocalization. RESULTS: We identified 774 unique independent SI-associated loci across all analyses, with 747 detected in the combined-sex GWAS, 283 in the male-stratified GWAS, and 311 in the female-stratified GWAS; 367 of these loci had not been previously reported for conventional sarcopenia-related traits. Sex-stratified analyses highlighted the rs1145093-chr15q21.1-GATM region, where CARMA identified sex-differentiated causal variants. We prioritized 17 male-biased and 11 female-biased credible genes. Enrichment analyses implicated androgen receptor and GATA4 in males, and ESR1 and MYOD1 in females. Enrichment revealed shared pathways involving inflammation, cellular stress, and aging-related processes. LDSC showed inverse genetic correlations between SI and heart failure (rg = -0.19, p = 2.30 × 10- 9) and metabolic syndrome (rg = -0.12, p = 8.49 × 10- 8), and a positive correlation with chronic kidney disease. Compared with female SI, male SI exhibited two additional loci showing colocalization with four metabolic traits. CONCLUSIONS: These findings clarify the genetic architecture of SI and reveal sex-dependent mechanisms underlying sarcopenia, supporting precision risk assessment and targeted interventions.

Humans

Luteolin is associated with alleviation of cigarette smoke-induced cellular senescence and inflammation in mice involving the CREB/c-Fos/NQO1 pathway.

Cigarette smoke (CS) exposure is a major risk factor for chronic obstructive pulmonary disease (COPD) and is closely associated with cellular senescence. Previous studies have demonstrated the efficacy of luteolin in treating aging-related symptoms. This study aims to elucidate the therapeutic potential of luteolin against CS-induced cellular senescence. Using a CS-exposed mouse model and cigarette smoke extract (CSE) treated mouse lung epithelial cells (TC-1), we demonstrate that luteolin significantly attenuates CS-induced histopathological alterations and inflammatory cytokine release while alleviating cellular senescence. Transcriptome sequencing suggests that NQO1 and Fos may serve as a common molecular target for both CS-induced pathology and luteolin treatment. Subsequent Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) enrichment analysis and pathway validation experiments revealed that the cAMP agonist Forskolin inhibits senescence marker expression by activating the CREB pathway, exhibiting a mechanism similar to that of luteolin. Notably, luteolin activation of this pathway may not depend on PKA activation. Ultimately, the study found that luteolin mitigates inflammatory responses and prevents lung epithelial cell senescence via the CREB/c-Fos/NQO1 pathway. These findings not only suggest the pivotal role of NQO1 in regulating CS-induced cellular senescence but also underscore the potential of luteolin as a therapeutic drug.

Animals

Chaperone-mediated autophagy as a regulator of hallmarks of cancer.

Chaperone-mediated autophagy (CMA) is a selective lysosomal degradation pathway that maintains cellular homeostasis by degrading soluble proteins containing KFERQ-like motifs. Although CMA has traditionally been recognized for its role in protein quality control and cellular stress adaptation, increasing evidence shows that it is frequently altered in cancer, where it regulates multiple processes that promote tumor initiation, progression, and therapy resistance. The growing number of identified CMA substrates involved in cell proliferation, apoptosis, metabolism, DNA damage response, immune regulation, inflammation, and cellular plasticity suggests that CMA is much more than a protein degradation pathway; it is an important regulator of tumor adaptation. In this review, we bring together current evidence to provide a comprehensive understanding of how CMA contributes to the Hallmarks of Cancer, including sustained proliferative signaling, resistance to cell death, metabolic reprogramming, invasion and metastasis, immune evasion, and the enabling characteristics of genome instability and tumor-promoting inflammation. We further explore the emerging roles of CMA in cellular plasticity and cancer stem cell maintenance, two interconnected processes that drive tumor progression, metastasis, and therapeutic resistance. By integrating evidence from diverse tumor types, this review provides a comprehensive understanding of how CMA shapes multiple hallmarks of cancer by selectively degrading key regulatory proteins. Finally, we highlight the context-dependent roles of CMA, identify key gaps in our current understanding, and discuss the opportunities and challenges of targeting CMA for cancer therapy. Overall, this hallmark-based perspective provides an integrated understanding of how CMA contributes to multiple hallmarks of cancer and supports its potential as a therapeutic target.

autophagy

Hope is linked with more favorable tumor molecular signatures in serous ovarian cancer.

INTRODUCTION: Hope has been associated with improved quality of life and lower mortality in cancer, but the underlying biological mechanisms are poorly characterized. We previously reported that hope was associated with less inflammation and more normalized diurnal cortisol pre-treatment among women with ovarian cancer. We also reported associations of socio-environmental factors with pro-metastatic processes. Here, we used genome-wide transcriptional profiling to quantify associations between hope and tumor molecular signatures reflecting invasiveness, inflammation, and cellular immunity. METHOD: Participants were 74 women with serous ovarian cancer who provided demographic information and completed surveys pre-surgery. Hope was assessed using a face-valid item from the Center for Epidemiological Studies Depression Scale (CES-D). Depression was assessed using the full CES-D without the hope item. Illumina HT12 microarrays were used to assay tumor RNA, and associations between hope and tumor gene expression were quantified, adjusting for depression, age, BMI, grade, and stage. RESULTS: Adjusting for covariates, hope was associated with multiple favorable differences in RNA expression, including lower levels of mesenchymal differentiation (p&#x202f;=&#x202f;0.008) and pro-inflammatory gene regulation (NF-&#x3ba;B: p&#x202f;<&#x202f;0.001; IRF1: p&#x202f;=&#x202f;0.024; STAT: p&#x202f;=&#x202f;0.018), elevated epithelial differentiation (p&#x202f;=&#x202f;0.011), and elevated activity of the IRF7 transcription factor which promotes cellular immunity (p&#x202f;=&#x202f;0.016). CONCLUSIONS: These data suggest that hope is associated with an ovarian tumor gene expression profile characterized by reduced epithelial-mesenchymal transition (EMT) and inflammatory activity, and increased activity of a transcription factor promoting cellular immunity. These findings highlight potential biological implications of a resilience factor such as hope, but need replication with more robust assessments of hope.

Epithelial mesenchymal transition

Single-cell multi-omics dissects transcript isoform and immune repertoire dynamics in human immunosenescence.

Immunosenescence, a major hallmark of systemic aging, refers to the progressive functional decline of the immune system. This decline not only compromises host defense and immunological memory but also fuels chronic inflammation and tissue degeneration (collectively known as inflammaging). While single-cell RNA sequencing (scRNA-seq) has revealed transcriptomic alterations associated with immune aging, analyses restricted to transcript abundance fail to capture deeper regulatory layers, such as transcript isoform diversity and the remodeling of immune receptor repertoires. To address this limitation, we present a human peripheral immune single-cell multi-omics atlas that integrates gene expression, transcript isoform diversity, and immune receptor repertoires. By combining single-cell full-length transcriptome sequencing (scCycloneSEQ), short-read scRNA-seq, and single-cell immune receptor sequencing (scTCR/BCR-seq), we systematically profiled peripheral blood mononuclear cells (PBMCs) from healthy donors aged 30-40 and 60-70 years. Our analyses uncovered extensive age-related remodeling of immune cell composition, functional states, and TCR/BCR diversity. Notably, we found that CD4+ effector memory T cells exhibited widespread differential isoform usage (DIU), 3'UTR length variation, and a marked reshaping of cytotoxic T lymphocyte (CTL) clonotypes-all of which were closely associated with aging-related inflammation and cellular senescence. This multi-omics atlas delineates key molecular features of immunosenescence and provides a high-resolution resource for deciphering the regulatory architecture underlying immune aging.

TCR/BCR

Silencing FAF2 mitigates alcohol-induced hepatic steatosis by modulating lipolysis and PCSK9 pathway.

BACKGROUND: Chronic alcohol consumption leads to lipid accumulation, oxidative stress, cellular damage, and inflammation in the liver, collectively referred to as alcohol-associated liver disease (ALD). FAF2/UBXD8/ETEA (Fas-associated factor 2) is a ubiquitin ligase adaptor protein that plays a crucial role in the ubiquitin-mediated degradation of misfolded proteins in the endoplasmic reticulum. A recent genome-wide association study indicated an association between FAF2 and ALD; however, the exact contribution of FAF2 to ALD pathogenesis remains unclear. METHODS: FAF2 was knocked down using AAV-delivered shRNA in C57/BL6 mice. Mice were subjected to a chronic-plus-single binge ethanol feeding (NIAAA) model. Nine hours after gavage, liver, blood, and other organs of interest were collected for gene expression and biochemical analyses. RESULTS: We first observed a significant elevation in hepatic FAF2 protein expression in individuals with ALD and in mice subjected to an ethanol-binge model. Interestingly, knocking down FAF2 in the liver using adeno-associated virus serotype 8-delivered short hairpin RNA conferred a protective effect against alcohol-induced liver steatosis in ethanol-binged mice. Transcriptomic analysis revealed that differentially expressed genes were enriched in multiple lipid metabolism regulation pathways. Further analysis of transcription factors regulating these differentially expressed genes suggested potential regulation by SREBP1. Several SREBP1 target genes, including Fasn, Scd1, Lpin1, and Pcsk9 (proprotein convertase subtilisin/kexin type 9), were dysregulated in the livers of ethanol-fed FAF2 knockdown mice. Additionally, Pcsk9 could be regulated through the FOXO3-SIRT6 pathway in the livers of ethanol-fed FAF2 knockdown mice, leading to increased liver low-density lipoprotein receptor expression and reduced plasma LDL cholesterol levels. Furthermore, FAF2 knockdown in mouse liver enhanced adipose triglyceride lipase lipolytic activity by upregulating the adipose triglyceride lipase activator, comparative gene identification-58, and downregulating the adipose triglyceridelipase transport inhibitor, Elmod2, contributing to the alleviation of liver steatosis. CONCLUSIONS: Our study uncovers a novel mechanism involving FAF2 in the pathogenesis of ALD.

Animals

Thrombin concentration shapes endothelial extracellular vesicle profiles with divergent inflammatory functions.

Thrombin, a central enzyme in the coagulation cascade, also regulates diverse cellular processes, including inflammation and vascular barrier function, primarily by activating protease-activated receptor 1. Previous studies demonstrated that thrombin elicits concentration-dependent, opposing effects; low concentrations confer anti-inflammatory and barrier-protective responses, whereas high concentrations promote inflammation and barrier disruption. The underlying mechanisms, however, remain incompletely understood. Here, we showed that thrombin stimulates extracellular vesicle (EV) release from endothelial cells across a broad concentration range and that EVs generated at low vs high thrombin concentrations carry distinct microRNA (miR) cargo. Low-thrombin EVs mediate cytoprotective responses via the transfer of miR-409-5p, which targets ubiquitin-specific protease 7 that promotes inflammation via the NF-kB signaling pathway in recipient cells, whereas high-thrombin EVs disrupt barrier integrity and promote inflammation through delivery of miR-155-5p, a regulator of suppressor of cytokine signaling 1 that acts as a crucial negative regulator of the cytokine signaling pathway. Functional manipulation of these EVs confirmed the causal roles. Incorporation of anti-miR-409-5p abrogated the protective effects of low-thrombin EVs, whereas anti-miR-155-5p suppressed the cytopathic effects of high-thrombin EVs. Moreover, control EVs engineered to carry a miR-409-5p mimic reproduced the anti-inflammatory and barrier-protective phenotype of low-thrombin EVs. Collectively, these findings identified EV-associated miRs as key mediators of the concentration-dependent dual actions of thrombin, which may open the therapeutic potential of EVs engineered to deliver selective miRs or anti-miRs for the treatment of inflammatory vascular diseases.

Thrombin

Targeting CyclinD1-CDK6 to Mitigate Senescence-Driven Inflammation and Age-Associated Functional Decline.

Cellular senescence contributes to aging and age-related diseases by driving chronic inflammation through the Senescence Associated Secretory Phenotype (SASP) and interferon-stimulated genes (ISGs). Cyclin D1 (CCND1), a key cell cycle regulator, is paradoxically upregulated in these non-proliferating cells. We show that CCND1 and its kinase partner CDK6 drive SASP and ISG expression in senescent cells by promoting DNA damage accumulation. This leads to the formation of cytoplasmic chromatin fragments (CCFs) that activate pro-inflammatory CGAS-STING signaling. The tumor suppressor p53 (TP53) and its target p21 (CDKN2A) antagonize this CCND1-CDK6-dependent DNA damage accumulation pathway to suppress the SASP. In aged mouse livers, senescent hepatocytes show increased Ccnd1 expression. Hepatocyte-specific Ccnd1 knockout or treatment with the Cdk4/6 inhibitor Palbociclib reduces DNA damage and ISGs in aged mouse liver. Notably, Palbociclib also suppresses frailty and improves physical performance of aged mice. These findings reveal a novel role for CCND1/CDK6 in regulating DNA damage and inflammation in senescence and aging, highlighting it as a promising therapeutic target.

Journal Article

Biological Mechanisms Underlying the Cardiovascular Effects of Branched-Chain Amino Acids: A Proteome-Wide Mendelian Randomization Study.

BACKGROUND: Ischemic heart disease (IHD) is the leading cause of morbidity and mortality. Branched-chain amino acids (BCAAs) are associated with higher IHD risk, but the underlying biological pathways remain unclear. OBJECTIVES: This study aims to explore these pathways using 2-step proteome-wide Mendelian randomization. METHODS: We examined the associations between genetic proxies for BCAAs and 2922 proteins in the United Kingdom Biobank Pharma Proteomics Project, supplemented by a meta-analysis with data from deCODE to identify proteins associated with BCAAs. Next, we tested their effects on IHD risk using Coronary Artery Disease Genome-wide Replication and Meta-analysis plus Coronary Artery Disease Genetics Consortium (122,733 cases and 424,528 controls) and replicated in FinnGen (31,640 cases and 187,152 controls). We conducted sensitivity analyses using genetic instruments from deCODE. Proteins associated with IHD risk and, in a consistent direction, with genetically predicted BCAAs were considered potential mediators. RESULTS: Genetic proxies for BCAAs were associated with 40 proteins. Among these, 6 proteins showed consistent evidence of mediation, including complement C1s subcomponent, coagulation factor II, granulin, proprotein convertase subtilisin/kexin type 9, sex hormone-binding globulin, and V-set and transmembrane domain-containing protein 2-like. These proteins are involved in inflammation, coagulation, lipid metabolism, and cellular stress response. All associations were robust across different analytical methods and replicated in independent datasets. Mediation analysis showed that these proteins accounted for 6.5% to 32.1% of the association between BCAAs and IHD risk. CONCLUSIONS: This study identified 6 proteins that potentially link BCAAs to IHD, implicating pathways related to inflammation, coagulation, lipid metabolism, and cellular stress responses. To our knowledge, these findings provide novel mechanistic insights into the BCAA-IHD relationship and highlight potential protein targets for future prevention and intervention strategies.

Amino Acids, Branched-Chain

Time-dependent effects of rapid-acting antidepressants in iPSC-derived neurons from treatment-resistant depression and healthy volunteers.

Rapid-acting antidepressants like ketamine and serotonergic psychedelics show promise for treatment-resistant depression (TRD), but the molecular mechanisms that contribute to their therapeutic effects remain unclear. Induced pluripotent stem cells (iPSCs) offer a platform to model human cortical neurons and investigate drug effects in a human-relevant system. Here, iPSCs from individuals with TRD and healthy volunteers (HVs) were differentiated into mature cortical-like neurons and treated for six and 24&#x2009;h with agents being investigated as rapid-acting antidepressants, including (2&#x2009;R,6&#x2009;R)-hydroxynorketamine (HNK), psilocybin, lysergic acid diethylamide (LSD), and 2,5-Dimethoxy-4-iodoamphetamine (DOI). Bulk and single-cell RNA sequencing assessed global and cell-type-specific transcriptomic responses. Synaptic proteins were evaluated via Western blotting and immunocytochemistry. To validate translational relevance, transcriptomic results were compared to CSF proteomics from ketamine-treated HVs. Despite differing initial pharmacological targets, overall gene expression across all compounds was highly correlated at matched timepoints compared to vehicle control, suggesting shared downstream effects. Both glutamatergic and serotonergic drugs converged on pathways involving inflammation, mTORC1 signaling, and cellular growth. At the single-cell level, (2&#x2009;R,6&#x2009;R)-HNK showed distinct cell-type specific alterations: upregulation in excitatory neurons and concomitant downregulation of inhibitory neuron populations. Differentially expressed genes from (2&#x2009;R,6&#x2009;R)-HNK-treated neurons also overlapped with CSF proteomic signatures from ketamine-treated individuals, supporting the model's translational relevance. This study is the first to assess multiple putative rapid-acting antidepressants in parallel using an iPSC-derived neuron model. Both convergent and drug-specific changes in gene expression and pathway enrichment were observed across diverse compounds, supporting the use of human iPSC-derived neurons in antidepressant drug discovery. Clinical Trial Registry: www.clinical trials.gov, NCT02484456.

Journal Article

Time-Dependent Effects of Rapid-Acting Antidepressants in iPSC-Derived Neurons from Treatment-Resistant Depression and Healthy Volunteers.

UNLABELLED: Rapid-acting antidepressants like ketamine and serotonergic psychedelics show promise for treatment-resistant depression (TRD), but the molecular mechanisms that contribute to their therapeutic effects remain unclear. Induced pluripotent stem cells (iPSCs) offer a platform to model human cortical neurons and investigate drug effects in a human-relevant system. Here, iPSCs from individuals with TRD and healthy volunteers (HVs) were differentiated into mature cortical-like neurons and treated for six and 24 hours with agents being investigated as rapid-acting antidepressants, including (2R,6R)-hydroxynorketamine (HNK), psilocybin, lysergic acid diethylamide (LSD), and 2,5-Dimethoxy-4-iodoamphetamine (DOI). Bulk and single-cell RNA sequencing assessed global and cell-type-specific transcriptomic responses. Synaptic proteins were evaluated via Western blotting and immunocytochemistry. To validate translational relevance, transcriptomic results were compared to CSF proteomics from ketamine-treated HVs. Despite differing initial pharmacological targets, overall gene expression across all compounds was highly correlated at matched timepoints compared to vehicle control, suggesting shared downstream effects. Both glutamatergic and serotonergic drugs converged on pathways involving inflammation, mTORC1 signaling, and cellular growth. At the single-cell level, HNK showed distinct cell-type specific alterations: upregulation in excitatory neurons and concomitant downregulation of inhibitory neuron populations. Differentially expressed genes from HNK-treated neurons also overlapped with CSF proteomic signatures from ketamine-treated individuals, supporting the model's translational relevance. This study is the first to assess multiple putative rapid-acting antidepressants in parallel using an iPSC-derived neuron model. Both convergent and drug-specific changes in gene expression and pathway enrichment were observed across diverse compounds, supporting the use of human iPSC-derived neurons in antidepressant drug discovery. CLINICAL TRIAL REGISTRY: www.clinicaltrials.gov, NCT02484456.

Journal Article

Inhibiting cyclin D1-CDK6 suppresses senescence-associated inflammatory gene expression and age-related functional decline.

Cellular senescence contributes to aging and age-related diseases by driving chronic inflammation through the senescence-associated secretory phenotype (SASP), including interferon-stimulated genes (ISGs). Here we confirm and extend previous observations that cyclin D1 (CCND1), a key cell cycle regulator, is paradoxically upregulated across models of nonproliferating senescent cells. We show that CCND1 and its kinase partner CDK6 drive SASP and ISG expression in senescent cells by promoting DNA damage accumulation. This leads to the formation of cytoplasmic chromatin fragments that activate pro-inflammatory cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling. In aged mouse livers, senescent hepatocytes show increased Ccnd1 expression. Hepatocyte-specific Ccnd1 knockout or treatment with the clinical grade CDK4/6 inhibitor palbociclib reduces DNA damage and ISGs in aged mouse liver. Further, palbociclib suppresses frailty and improves physical performance of aged mice. These findings demonstrate a role for CCND1/CDK6 in regulating DNA damage and inflammation in senescence and aging, highlighting it as a promising target for therapeutic repurposing.

Animals

TNF-&#x3b1;/NF-&#x3ba;B mediated upregulation of Dectin-1 in hyperglycemic obesity: implications for metabolic inflammation and diabetes.

BACKGROUND: Dectin-1, a key innate immune receptor, plays a critical role in cellular responses and is implicated in chronic inflammation and metabolic syndromes. This study addresses a pivotal gap in elucidating the regulatory mechanism governing Dectin-1 expressionin obesity and diabetes, hypothesizing that hyperglycemia and TNF-&#x3b1; synergistically upregulate Dectin-1 in adipose tissue (AT), thereby exacerbating inflammatory responses and contributing to metabolic dysfunction. METHODS: The study included 95 overweight and obese Kuwaiti individuals, categorized into prediabetic (HbA1c&#x2009;<&#x2009;6.5%) and diabetic (HbA1c&#x2009;&#x2265;&#x2009;6.5%) groups. Anthropometric and clinical measurements were recorded. AT biopsies were obtained for RNA extraction and immunohistochemistry. Pre-adipocytes from lean and obese individuals were cultured, differentiated into adipocytes, and treated with TNF-&#x3b1; under normal or high-glucose conditions to assess Dectin-1 expression. Chromatin immunoprecipitation (ChIP) assays analyzed NF-&#x3ba;B binding to the Dectin-1 promoter. Wildtype and TNF-&#x3b1;-/- mice were used to evaluate TNF-&#x3b1;'s effect on Dectin-1 expression in AT. RESULTS: Our data demonstrate that hyperglycemic obesity significantly induces Dectin-1 expression in AT through the TNF-&#x3b1;/NF-&#x3ba;B signaling pathway. In a cohort of 95 obese individuals, subdivided into prediabetics (HbA1c&#x2009;<&#x2009;6.5%, n&#x2009;=&#x2009;49) and diabetics (HbA1c&#x2009;&#x2265;&#x2009;6.5%, n&#x2009;=&#x2009;46), a strong positive correlation was observed between AT Dectin-1 transcripts and plasma HbA1c levels exclusively in diabetic participants, underscoring the specificity of Dectin-1 upregulation in hyperglycemic conditions. Elevated Dectin-1 expression was consistently associated to increased inflammation markers. Immunohistochemical analysis revealed co-localization and concurrent upregulation of Dectin-1 and TNF-&#x3b1; proteins in hyperglycemic AT. Functional assays in TNF-&#x3b1; deficient mice and human adipocytes further validated that TNF-&#x3b1; and hyperglycemia act cooperatively to regulate Dectin-1 expression. Mechanistically, we demonstrated that NF-&#x3ba;B directly binds to the Dectin-1 promoter, mediating its transcriptional activation in response to glucose and TNF-&#x3b1;. CONCLUSION: This study significantly advances the understanding of upregulation Dectin-1 in metabolic inflammation, filling a crucial niche in diabetes research and suggesting new therapeutic targets for obesity-related metabolic disorders.

Humans

Inhibition of autophagy-lysosomal function exacerbates microglial and monocyte lipid metabolism reprograming and dysfunction after brain injury.

CNS has an overall higher level of lipids than all tissues except adipose and contains up to 25% of total body cholesterol. Recent data demonstrate a complex crosstalk between lipid metabolism and inflammation, suggesting potential contribution of the lipid-rich brain environment to neuroinflammation. While recent data support the importance of brain lipid environment to inflammatory changes observed in age related chronic neurodegenerative diseases, in vivo interactions between lipid environment, lipid metabolism and neuroinflammation in acute brain disease and injury remain poorly understood. Here we utilize a mouse model of traumatic brain injury (TBI) to demonstrate that acute neurotrauma leads to widespread lipid metabolism reprograming in all microglial and brain associated and infiltrating monocyte populations. Additionally, we identify unique microglial and monocyte populations with higher degree of lipid metabolism reprograming and pronounced accumulation of neutral storage lipids, including cholesteryl esters and triglycerides. These lipids accumulate not only in lipid droplets but also in the microglial and monocyte lysosomes and are associated with lysosomal dysfunction and inhibition of autophagy after TBI. Our data indicate that lipid accumulation in these cells is the result of altered lipid handling rather than lipid synthesis and is triggered by phagocytosis of lipid-rich myelin debris generated after TBI. Finally, we use mice with autophagy defects in microglia and monocytes to demonstrate that further inhibition of autophagy leads to more pronounced lipid metabolism reprograming and exacerbated cellular lipid accumulation. Our data suggest a pathological feedback loop, where lipid phagocytosis causes inhibition of autophagy-lysosomal function, which in turn exacerbates cellular lipid retention, reprograming and inflammation.

Journal Article

p53 enhances DNA repair and suppresses cytoplasmic chromatin fragments and inflammation in senescent cells.

Genomic instability and inflammation are distinct hallmarks of aging, but the connection between them is poorly understood. Here we report a mechanism directly linking genomic instability and inflammation in senescent cells through a mitochondria-regulated molecular circuit involving p53 and cytoplasmic chromatin fragments (CCF) that are enriched for DNA damage signaling marker &#x3b3;H2A.X. We show that p53 suppresses CCF accumulation and its downstream inflammatory phenotype. p53 activation suppresses CCF formation linked to enhanced DNA repair and genome integrity. Activation of p53 in aged mice by pharmacological inhibition of MDM2 reverses transcriptomic signatures of aging and age-associated accumulation of monocytes and macrophages in liver. Mitochondrial ablation in senescent cells suppresses CCF formation and activates p53 in an ATM-dependent manner, suggesting that mitochondria-dependent formation of &#x3b3;H2A.X&#x2009;+&#x2009;CCF dampens nuclear DNA damage signaling and p53 activity. These data provide evidence for a mitochondria-regulated p53 signaling circuit in senescent cells that controls DNA repair, genome integrity, and senescence- and age-associated inflammation, with relevance to therapeutic targeting of age-associated disease.

Animals