CCAAT/enhancer-binding protein beta (C/EBPβ) knockdown reduces inflammation, ER stress, and apoptosis, and promotes autophagy in oxLDL-treated RAW264.7 macrophage cells

Cholesterol Accumulation Promotes Photoreceptor Senescence and Retinal Degeneration

Purpose

Dysregulated cholesterol metabolism is critical in the pathogenesis of AMD. Cellular senescence contributes to the development of numerous age-associated diseases. In this study, we investigated the link between cholesterol burden and the cellular senescence of photoreceptors.

Methods

Retinas from rod-specific ATP binding cassette subfamily A member 1 (Abca1) and G member 1 (Abcg1) (Abca1/g1-rod/-rod) knockout mice fed with a high-fat diet were analyzed for the signs of cellular senescence. Real-time quantitative PCR and immunofluorescence were used to characterize the senescence profile of the retina and cholesterol-treated photoreceptor cell line (661W). Inducible elimination of p16(Ink4a)-positive senescent cells (INK-ATTAC) mice or the administration of senolytic drugs (dasatinib and quercetin: D&Q) were used to examine the impact of senolytics on AMD-like phenotypes in Abca1/g1-rod/-rod retina.

Results

Increased accumulation of senescent cells as measured by markers of cellular senescence was found in Abca1/g1-rod/-rod retina. Exogenous cholesterol also induced cellular senescence in 661W cells. Selective elimination of senescent cells in Abca1/g1-rod/-rod;INK-ATTAC mice or by administration of D&Q improved visual function, lipid accumulation in retinal pigment epithelium, and Bruch's membrane thickening.

Conclusions

Cholesterol accumulation promotes cellular senescence in photoreceptors. Eliminating senescent photoreceptors improves visual function in a model of retinal neurodegeneration, and senotherapy offers a novel therapeutic avenue for further investigation.

Implications of endoplasmic reticulum stress and autophagy in aging and cardiovascular diseases

The average lifespan of humans has been increasing, resulting in a rapidly rising percentage of older individuals and high morbidity of aging-associated diseases, especially cardiovascular diseases (CVDs). Diverse intracellular and extracellular factors that interrupt homeostatic functions in the endoplasmic reticulum (ER) induce ER stress. Cells employ a dynamic signaling pathway of unfolded protein response (UPR) to buffer ER stress. Recent studies have demonstrated that ER stress triggers various cellular processes associated with aging and many aging-associated diseases, including CVDs. Autophagy is a conserved process involving lysosomal degradation and recycling of cytoplasmic components, proteins, organelles, and pathogens that invade the cytoplasm. Autophagy is vital for combating the adverse influence of aging on the heart. The present report summarizes recent studies on the mechanism of ER stress and autophagy and their overlap in aging and on CVD pathogenesis in the context of aging. It also discusses possible therapeutic interventions targeting ER stress and autophagy that might delay aging and prevent or treat CVDs.

LXR/CD38 activation drives cholesterol-induced macrophage senescence and neurodegeneration via NAD+ depletion

Although dysregulated cholesterol metabolism predisposes aging tissues to inflammation and a plethora of diseases, the underlying molecular mechanism remains poorly defined. Here, we show that metabolic and genotoxic stresses, convergently acting through liver X nuclear receptor, upregulate CD38 to promote lysosomal cholesterol efflux, leading to nicotinamide adenine dinucleotide (NAD+) depletion in macrophages. Cholesterol-mediated NAD+ depletion induces macrophage senescence, promoting key features of age-related macular degeneration (AMD), including subretinal lipid deposition and neurodegeneration. NAD+ augmentation reverses cellular senescence and macrophage dysfunction, preventing the development of AMD phenotype. Genetic and pharmacological senolysis protect against the development of AMD and neurodegeneration. Subretinal administration of healthy macrophages promotes the clearance of senescent macrophages, reversing the AMD disease burden. Thus, NAD+ deficit induced by excess intracellular cholesterol is the converging mechanism of macrophage senescence and a causal process underlying age-related neurodegeneration.

Exosomal long non-coding RNA AU020206 alleviates macrophage pyroptosis in atherosclerosis by suppressing CEBPB-mediated NLRP3 transcription

Recent studies have suggested exosomes (EXO) as potential therapeutic tools for cardiovascular diseases, including atherosclerosis (AS). This study investigates the function of bone marrow stem cell (BMSC)-derived exosomes (EXO) on macrophage pyroptosis in AS and explores the associated mechanism. BMSC-EXO were isolated from healthy mice and identified. RAW264.7 cells (mouse macrophages) were exposed to oxLDL to simulate an AS condition. BMSC-EXO treatment enhanced viability and reduced lactate dehydrogenase release of macrophages. An animal model of AS was established using ApoE-/- mice. BMSC-EXO treatment suppressed plaque formation as well as macrophage and lipid infiltration in mouse aortic tissues. Moreover, BMSC-EXO decreased concentrations of pyroptosis-related markers interleukin (IL)-1β, IL-18, cleaved-caspase-1 and gasdermin D in vitro and in vivo. Long non-coding RNA AU020206 was carried by the BMSC-EXO, and it bound to CCAAT enhancer binding protein beta (CEBPB) to block CEBPB-mediated transcriptional activation of NLR family pyrin domain containing 3 (NLRP3). Functional assays revealed that silencing of AU020206 aggravated macrophage pyroptosis and exacerbated AS symptoms in mice. These exacerbations were blocked upon CEBPB silencing but then restored after NLRP3 overexpression. In conclusion, this study demonstrates that AU020206 delivered by BMSC-EXO alleviates macrophage pyroptosis in AS by blocking CEBPB-mediated transcriptional activation of NLRP3.

Retinoids and EZH2 inhibitors cooperate to orchestrate anti-oncogenic effects on bladder cancer cells

The highly mutated nature of bladder cancers harboring mutations in chromatin regulatory genes opposing Polycomb-mediated repression highlights the importance of targeting EZH2 in bladder cancer. Furthermore, the critical role of the retinoic acid signaling pathway in the development and homeostasis of the urothelium, and the anti-oncogenic effects of retinoids are well established. Therefore, our aim is to simultaneously target EZH2 and retinoic acid signaling in bladder cancer to potentiate the therapeutic response. Here we report that this coordinated targeting strategy stimulates an anti-oncogenic profile, as reflected by inducing a synergistic reduction in cell viability that was associated with increased apoptosis and cell cycle arrest in a cooperative and orchestrated manner. This study characterized anti-oncogenic transcriptional reprogramming centered on the transcriptional regulator CHOP by stimulating the endoplasmic reticulum stress response. We further portrayed a molecular mechanism whereby EZH2 maintains H3K27me3-mediated repression of a subset of genes involved in unfolded protein responses, reflecting the molecular mechanism underlying this co-targeting strategy. These findings highlight the importance of co-targeting the EZH2 and retinoic acid pathway in bladder cancers and encourage the design of novel treatments employing retinoids coupled with EZH2 inhibitors in bladder carcinoma.

Hypoxia/inflammation-induced upregulation of HIF-1α and C/EBPβ promotes nephroblastoma cell EMT by improving HOXA11-AS transcription

Background

Homeobox (HOX) A11 antisense RNA (HOXA11-AS) has been identified as a cancer promoting lncRNA and is overexpressed in nephroblastoma. However, how HOXA11-AS is regulated in a hypoxic inflammatory environment has not been studied.

Methods

In this study, gene expression and epithelial-mesenchymal transition (EMT) ability were detected in the nephroblastoma cell line WiT49 under conditions of hypoxia and inflammation. Next, HOXA11-AS transcription factors were predicted by datasets and subsequently confirmed by CHIP-QPCR, EMSA, and dual-luciferase reporter assays. Moreover, the regulatory relationships of HOXA11-AS and its transcription factors were further confirmed by rescue experiments.

Results

Our results showed that a hypoxic microenvironment promoted HOXA11-AS expression and nephroblastoma progression, induced EMT, and activated the Wnt signaling pathway. Combined hypoxia and inflammation had a more substantial effect on nephroblastoma than either hypoxia or inflammation alone. HIF-1α and C/EBPβ were confirmed to be the transcription factors for HOXA11-AS. Silencing of HIF-1α or C/EBPβ downregulated HOXA11-AS expression and suppressed EMT and the Wnt signaling pathway in nephroblastoma cells exposed to a hypoxic or inflammatory microenvironment. HOXA11-AS overexpression partly reversed the effect of HIF-1α or C/EBPβ knockdown.

Conclusion

We demonstrated that hypoxia/inflammation-induced upregulation of HIF-1α and C/EBPβ promoted nephroblastoma EMT by improving HOXA11-AS transcription. HOXA11-AS might be a therapy target for nephroblastoma.

E3 ubiquitin ligase COP1-mediated CEBPB ubiquitination regulates the inflammatory response of macrophages in sepsis-induced myocardial injury

CCAAT/enhancer-binding protein beta (CEBPB) has been associated with sepsis. However, its role in sepsis-induced myocardial injury (SIMI) remains ill-defined. This research was designed to illustrate the involvement of CEBPB in SIMI and its upstream modifier. The transcriptomic changes in heart biopsies of mice that had undergone polymicrobial sepsis were downloaded from the GEO dataset for KEGG enrichment analysis. CEBPB, on the TNF signaling pathway, was significantly enhanced in the myocardial tissues of mice with SIMI. Downregulation of CEBPB alleviated SIMI, as evidenced by minor myocardial injury and inflammatory manifestations. Moreover, ubiquitination modification of CEBPB by constitutive photomorphogenesis protein 1 homolog (COP1) led to the degradation of CEBPB and inhibited inflammatory responses in macrophages. Upregulation of COP1 protected against SIMI in mice overexpressing CEBPB. Collectively, our findings demonstrated that COP1 protected the heart against SIMI through the ubiquitination modification of CEBPB, which might be a novel therapeutic approach in the future.

Top Five Stories of the Cellular Landscape and Therapies of Atherosclerosis: Current Knowledge and Future Perspectives

Atherosclerosis (AS) is characterized by impairment and apoptosis of endothelial cells, continuous systemic and focal inflammation and dysfunction of vascular smooth muscle cells, which is documented as the traditional cellular paradigm. However, the mechanisms appear much more complicated than we thought since a bulk of studies on efferocytosis, transdifferentiation and novel cell death forms such as ferroptosis, pyroptosis, and extracellular trap were reported. Discovery of novel pathological cellular landscapes provides a large number of therapeutic targets. On the other side, the unsatisfactory therapeutic effects of current treatment with lipid-lowering drugs as the cornerstone also restricts the efforts to reduce global AS burden. Stem cell- or nanoparticle-based strategies spurred a lot of attention due to the attractive therapeutic effects and minimized adverse effects. Given the complexity of pathological changes of AS, attempts to develop an almighty medicine based on single mechanisms could be theoretically challenging. In this review, the top stories in the cellular landscapes during the initiation and progression of AS and the therapies were summarized in an integrated perspective to facilitate efforts to develop a multi-targets strategy and fill the gap between mechanism research and clinical translation. The future challenges and improvements were also discussed.

Protective effect of TNFAIP3 on testosterone production in Leydig cells under an aging inflammatory microenvironment

BACKGROUND

The aging inflammatory microenvironment surrounding Leydig cells is linked to reduced testosterone levels in males. Tumor necrosis factor alpha-induced protein 3 (TNFAIP3) acts as a critical anti-inflammatory factor in various aging-related diseases. This study aims to investigate the protective effect of TNFAIP3 on testosterone production in Leydig cells under an aging inflammatory microenvironment.

METHODS

Bioinformatics analysis examined TNFAIP3 expression differences in aging rat testes and validated the findings in aging mouse testes. In vitro models of inflammation were established using two Leydig cell lines, with tumor necrosis factor alpha (TNF-α) as the inflammatory factor. Lentiviral transduction was utilized to manipulate TNFAIP3 expression in these cell lines. Transcriptomic sequencing identified differentially expressed genes in TNFAIP3-overexpressing cells.

RESULTS

Bioinformatics analysis and validation experiments revealed increased inflammatory signaling and elevated TNFAIP3 expression in aging rat and mouse testes. TNFAIP3 knockdown worsened testosterone synthesis inhibition and apoptosis in cells, while TNFAIP3 overexpression reversed these effects. Transcriptome analysis identified alterations in the P38MAPK pathway following TNFAIP3 overexpression. TNFAIP3 knockdown enhanced TNF-induced P38MAPK signaling, whereas its overexpression attenuated this effect. TNFAIP3 was found to regulate testosterone synthesis by upregulating CEBPB expression.

CONCLUSIONS

TNFAIP3 exhibits inhibitory effects on apoptosis and promotes testosterone production in Leydig cells. The protective influence of TNFAIP3 on Leydig cells within an inflammatory microenvironment is likely mediated through by inhibiting the P38MAPK pathway and upregulating CEBPB expression.

Exploratory Study of Differentially Expressed Genes of Peripheral Blood Monocytes in Patients with Carotid Atherosclerosis

BACKGROUND

The abundance of circulating monocytes is closely associated with the development of atherosclerosis in humans.

OBJECTIVE

This study aimed to further research into diagnostic biomarkers and targeted treatment of carotid atherosclerosis (CAS).

METHODS

We performed transcriptomics analysis through weighted gene co-expression network analysis (WGCNA) of monocytes from patients in public databases with and without CAS. Differentially expressed genes (DEGs) were screened by R package limma. Diagnostic molecules were derived by the least absolute shrinkage and selection operator (LASSO) and support vector machine recursive feature elimination (SVM-RFE) algorithms. NetworkAnalyst, miRWalk, and Star- Base databases assisted in the construction of diagnostic molecule regulatory networks. The Drug- Bank database predicted drugs targeting the diagnostic molecules. RT-PCR tested expression profiles.

RESULTS

From 14,369 hub genes and 61 DEGs, six differentially expressed monocyte-related hub genes were significantly associated with immune cells, immune responses, monocytes, and lipid metabolism. LASSO and SVM-RFE yielded five genes for CAS prediction. RT-PCR of these genes showed HMGB1 was upregulated, and CCL3, CCL3L1, CCL4, and DUSP1 were downregulated in CAS versus controls. Then, we constructed and visualized the regulatory networks of 9 transcription factors (TFs), which significantly related to 5 diagnostic molecules. About 11 miRNAs, 19 lncRNAs, and 39 edges centered on four diagnostic molecules (CCL3, CCL4, DUSP1, and HMGB1) were constructed and displayed. Eleven potential drugs were identified, including ibrutinib, CTI-01, roflumilast etc. Conclusion: A set of five biomarkers were identified for the diagnosis of CAS and for the study of potential therapeutic targets.

Shenlian extract protected ox-LDL-loaded macrophages against ER stress by promoting LAL-LXRα mediated cholesterol flux

ETHNOPHARMACOLOGICAL RELEVANCE

Shenlian (SL) extract is consisted of extracts from Salvia miltiorrhiza Bunge and Andrographis paniculata (Burm.f.) Nees, two herbs commonly used in Chinese clinical formula to treat atherosclerosis by removing blood stasis and clearing away heat. Pharmacologically, the anti-atherosclerotic effects of these two herbs are related to unresolved inflammation and the macrophage anergy or apoptosis in lesions led by the lipid flux blockage and ER stress. However, the deeper understanding of SL extract in protecting macrophage in plaques remains unknown.

AIM OF THE STUDY

This study aimed to investigate the underlying mechanism of SL extract in protecting ER-stressed macrophages from apoptosis in atherosclerosis.

METHODS

The ApoE-/- atherosclerotic mice model and ox-LDL loaded macrophages model were established to assess the effect of SL extract on ER stress in vivo and in vitro. Key markers related to ER stress in plaque were determined by immunohistochemical staining. Proteins involved in apoptosis and ER stress in macrophages loaded by ox-LDL were assessed by Western blot. ER morphology was observed by electron microscope. Lipid flux was temporally and quantitatively depicted by Oil red staining. The LAL and LXRα were blocked by lalistat and Gsk 2033 respectively to investigate whether SL extract protected the function of macrophages by the activation of LAL-LXRα axis.

RESULTS

Our study reported that, in ApoE-/- atherosclerotic mice, SL extract effectively relieved ER stress of carotid artery plaque. In lipid-overloaded macrophage models, SL extract significantly alleviated ER stress by promoting cholesterol degradation and efflux, which finally prevented apoptosis of foam cells induced by ox-LDL. Blockage of ER stress by 4-Phenylbutyric acid (4-PBA), an inhibitor of Endoplasmic Reticulum (ER) stress, largely attenuated the protective effects of SL extract on macrophage. By utilizing the selective antagonists against both LAL and LXRα, this study further revealed that the beneficial effects of SL extract in macrophages was dependent on the proper functionalization of LAL-LXRα axis.

CONCLUSIONS

By highlighting the therapeutic significance of macrophage protection in resolving atherosclerosis inflammation, our study pharmacologically provided convincing mechanistic evidence of SL extract in the activation LAL-LXRα axis and revealed its promising potential in the promotion of cholesterol turnover and prevention of ER stress induced apoptosis in lipid-loaded macrophages.

The engagement of autophagy in maniac disease

AIMS

Mania is a prevalent psychiatric disorder with undefined pathological mechanism. Here, we reviewed current knowledge indicating the potential involvement of autophagy dysregulation in mania and further discussed whether targeting autophagy could be a promising strategy for mania therapy.

DISCUSSIONS

Accumulating evidence indicated the involvement of autophagy in the pathology of mania. One of the most well-accepted mechanisms underlying mania, circadian dysregulation, showed mutual interaction with autophagy dysfunction. In addition, several first-line drugs for mania therapy were found to regulate neuronal autophagy. Besides, deficiencies in mitochondrial quality control, neurotransmission, and ion channel, which showed causal links to mania, were intimately associated with autophagy dysfunction.

CONCLUSIONS

Although more efforts should be made to either identify the key pathology of mania, the current evidence supported that autophagy dysregulation may act as a possible mechanism involved in the onset of mania-like symptoms. It is therefore a potential strategy to treat manic disorder by correting autophagy.

Activation of BZW1 by CEBPB in macrophages promotes eIF2α phosphorylation-mediated metabolic reprogramming and endoplasmic reticulum stress in MRL/lpr lupus-prone mice

BACKGROUND

Lupus nephritis (LN) is associated with significant mortality and morbidity, while effective therapeutics and biomarkers are limited since the pathogenesis is complex. This study investigated the roles of the CEBPB/BZW1/eIF2α axis in metabolic reprogramming and endoplasmic reticulum stress in LN.

METHOD

The differentially expressed genes in LN were screened using bioinformatics tools. The expression of CEBPB in the renal tissue of patients with LN and its correlation with the levels of creatinine and urinary protein were analyzed. We used adenoviral vectors to construct LN mice with knockdown CEBPB using MRL/lpr lupus-prone mice and analyzed the physiological and autoimmune indices in mice. Chromatin immunoprecipitation quantitative polymerase chain reaction (ChIP-qPCR) and dual-luciferase reporter assays were conducted to explore the regulation of BZW1 by CEBPB, followed by glycolytic flux analysis, glucose uptake, and enzyme-linked immunosorbent assay (ELISA). Finally, the role of eIF2α phosphorylation by BZW1 in bone marrow-derived macrophages (BMDM) was explored using eIF2α phosphorylation and endoplasmic reticulum stress inhibitors.

RESULTS

CEBPB was significantly increased in renal tissues of patients with LN and positively correlated with creatinine and urine protein levels in patients. Downregulation of CEBPB alleviated the autoimmune response and the development of nephritis in LN mice. Transcriptional activation of BZW1 by CEBPB-mediated glucose metabolic reprogramming in macrophages, and upregulation of BZW1 reversed the mitigating effect of CEBPB knockdown on LN. Regulation of eIF2α phosphorylation levels by BZW1 promoted endoplasmic reticulum stress-amplified inflammatory responses in BMDM.

CONCLUSION

Transcriptional activation of BZW1 by CEBPB promoted phosphorylation of eIF2α to promote macrophage glycolysis and endoplasmic reticulum stress in the development of LN.

Schwann cell derived-peroxiredoxin protects motor neurons against hydrogen peroxide-induced cell death in mouse motor neuron cell line NSC-34

Schwann cells and oligodendrocytes secrete proteins that promote neuron survival, but their role in amyotrophic lateral sclerosis (ALS) is unclear. To address this question, we evaluated the effect of molecules secreted by Schwann cells on reactive oxygen species (ROS)-induced motor neuronal cell death. We observed that in motor neuron cell line NSC-34 cultures, the conditioned medium (CM) from Schwann cell line YST-1 (YST-1 CM) cultures had a protective effect against hydrogen peroxide-induced cell death. However, this protective effect of YST-1 CM was abolished by removing peroxiredoxin 1-4 (PRDX1-4) from the CM. We found that the expression of PRDX1 mRNA was markedly downregulated in the lumbar spinal cord of the superoxide dismutase 1 (SOD1)G93A mouse model of ALS. We also found that transient transfection of YST-1 cells with G93A SOD1 resulted in reduced PRDX1 mRNA expression. Additionally, in the mutant transfected cells, YST-1 CM showed decreased neuroprotective effect against hydrogen peroxide-induced NSC-34 cell death compared to those transfected with WT SOD1. Our results suggest that Schwann cells protect motor neurons from oxidative stress by secreting PRDX1 and that the reduction of PRDX secreted from Schwann cells contributes to increased ROS and associated motor neuronal death in ALS.

Regulatory mechanisms underlying endoplasmic reticulum stress involvement in the development of gestational diabetes mellitus entail the CHOP-PPARα-NF-κB pathway

OBJECTIVE

We investigated the proinflammatory functions of endoplasmic reticulum stress and peroxisome proliferator-activated receptor α (PPARα) in the development of gestational diabetes mellitus (GDM) and their relationship in regulating inflammation in GDM.

METHODS

This study was performed on placentas of normal pregnant women, women with GDM, and HTR8 cells. Transmission electron microscopy, immunohistochemistry, Western blot analysis, and RT-PCR were performed to analyze ERS and PPARα expression on both normal and GDM pregnancy placentas. ELISA was performed to analyze inflammatory biomarkers. To generate models of the GDM-like state, placentas of normal pregnancy were treated with LPS and polyinosinic-polycytidylic acid (poly [I:C]). TG, CHOP plasmid, and CHOP siRNA were assessed as to their regulation of HTR8 cells to discern the relationship between ERS and PPARα in regulating the inflammation associated with GDM.

RESULTS

ERS was elevated in GDM placentas, induced the secretion of IL-6 and TNF-α, and attenuated the expression of GLUT-4. PPARα was diminished in GDM placentas and inhibited the inflammatory responses via the NF-κB nuclear-transport process. 4-PBA reduced CHOP and augmented PPARα, and it decreased IL-6 and TNF-α in our GDM-like explant. However, with both 4-PBA and MK886 treatment, we noted no significant difference in CHOP expression. The level of PPARα was reduced, and that of NF-κB p65 in the nucleus was elevated with TG treatment in the HTR8/Svneo. Knockdown of CHOP increased PPARα and reduced NF-κB p65, while expression of PPARα declined, and that of NF-κB p65 rose with the application of CHOP when HTR8 cells were treated with TG.

CONCLUSIONS

ERS contributes to the pathophysiology of GDM in pregnancy via the CHOP-PPARα-NF-κB-signalling pathway by inducing aberrant activation of inflammation and insulin resistance.

Immune landscape and regulatory mechanisms in human atherosclerotic coronary plaques: Evidence from single-cell and bulk transcriptomics

Atherosclerosis is a chronic immuno-inflammatory disease, however, the immune landscape and regulatory mechanisms have not been clear. We detected seven principal immune cell clusters with distinct phenotypic and spatial characteristics using single-cell RNA-sequencing of aortic immune cells from patients with acute coronary syndrome and stable angina pectoris. Then we acquired 265 differentially expressed immune-related genes and the high scores were mainly found in T cells and monocytes, which were differentially regulated in atherosclerotic coronary plaques. The CCL signaling pathway was the most relevant pattern in the T cells and CCL5-CCR1 and CCL5-CCR5 ligand-receptor pairs played a vital role in the CCL signaling pathway. Further comparative analysis indicated MCH-I signaling was the most relevant pattern in the T cells and HLA ligand-related ligand-receptor pairs played a vital role. Functional analysis of the single-cell and bulk transcriptomics pointed to multiple pathways, such as antigen presentation and immune response. Nineteen common differentially expressed immune-related genes were found in both immune cells and the human peripheral blood mononuclear cells. Nine common differentially expressed transcription factors were differentially expressed in both T cell and monocyte clusters from the coronary plaques and human peripheral blood mononuclear cells and the network demonstrated that CEBPB might play an essential role in the transcriptional regulation of atherosclerosis as a hub transcription factor. The definition of immune cell diversity and heterogeneity by single-cell level analysis of aortic immune cell subsets not only unveils cell-type-specific pathways and new immune mechanisms but also discovers the functional correlation of immune cells in human atherosclerosis. Our findings provide great promise for the discovery of novel molecular mechanisms and precise therapeutic targets for atherosclerosis.

Jintiange proteins promote osteogenesis and inhibit apoptosis of osteoblasts by enhancing autophagy via PI3K/AKT and ER stress pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Tiger bone, which had long been used in traditional Chinese medicine, had the action of removing wind and alleviating pain, strengthening the sinews and bones, and often used to treat bone impediment, and atrophic debility of bones in TCM clinical practice. As a substitute of natural bone tiger, artificial tiger bone Jintiange (JTG), has been approved by the State Food and Drug Administration of China for relief the symptom of osteoporosis, such as lumbago and back pain, lassitude in loin and legs, flaccidity and weakness legs, and walk with difficulty based on TCM theory. JTG has similar chemical profile to natural tiger bone, and contains mineral substance, peptides and proteins, and has been shown to protect bone loss in ovariectomized mice and exert the regulatory effects on osteoblast and osteoclast activities. But how the peptides and proteins in JTG modulate bone formation remains unclear.

AIM

To investigate the stimulating effects of JTG proteins on osteogenesis and explore the possible underlying mechanisms.

MATERIALS AND METHODS

JTG proteins were prepared from JTG Capsules by extracting calcium, phosphorus and other inorganic elements using SEP-PaktC18 desalting column. MC3T3-E1 cells were treated with JTG proteins to evaluate their effects and explore the underlying mechanisms. Osteoblast proliferation was detected by CCK-8 method. ALP activity was detected using a relevant assay kit, and bone mineralized nodules were stained with alizarin red-Tris-HCl solution. Cell apoptosis was analyzed by flow cytometry. Autophagy was observed by MDC staining, and autophagosomes were observed by TEM. Nuclear translocations of LC3 and CHOP were detected by immunofluorescence and observed under a laser confocal microscope. The expression of key proteins related to osteogenesis, apoptosis, autophagy and PI3K/AKT and ER stress pathways was analyzed by Western Blot analysis.

RESULTS

JTG proteins improved osteogenesis as evidenced by the alteration of proliferation, differentiation and mineralization of MC3T3-E1 osteoblasts, inhibited their apoptosis, and enhanced autophagosome formation and autophagy. They also regulated the expression of key proteins of PI3K/AKT and ER stress pathways. In addition, PI3K/AKT and ER stress pathway inhibitors could reverse the regulatory effects of JTG proteins on osteogenesis, apoptosis, autophagy and PI3K/AKT and ER stress pathways.

CONCLUSION

JTG proteins increased the osteogenesis and inhibited osteoblast apoptosis by enhancing autophagy via PI3K/AKT and ER stress signaling pathways.

JMJD3 downregulates IL4i1 aggravating lipopolysaccharide-induced acute lung injury via H3K27 and H3K4 demethylation

The pro-inflammation M1 to anti-inflammation M2 macrophage ratio contribute to the severity of lipopolysaccharide (LPS)-induced acute lung injury (ALI). JMJD3 aggravates the inflammatory reaction through affecting epigenetic modification and macrophage's phenotype to deteriorate ALI. To explore the mechanism underlying the upregulation of the macrophage M1/M2 ratio through JMJD3, we developed an ALI mouse model using intratracheal LPS, LPS-stimulated RAW 264.7 cells, and inhibited JMJD3 using GSK-J4. H3K27me3 and H3K4me3 were investigated as JMJD3-mediated epigenetic alteration sites in vivo and in vitro. C/EBPβ and KDM5A were validated as linking factors between H3K27 and H3K4. IL4i1 was investigated as a JMJD3-mediated targeted gene to regulate the macrophage M1/M2 ratio. Chromatin immunoprecipitation was used to evaluate the relationship between H3K27me3 and C/ebpβ, C/EBPβ and Kdm5a, H3K4me3 and Il4i1. Inhibiting JMJD3 with GSK-J4 can relieve inflammation and pathological performance in ALI. JMJD3 can reduce IL4i1 expression to increase the macrophage M1/M2 ratio and aggravated ALI which process was mediated via JMJD3-indcued H3K27me3 and H3K4me3 demethylation, latter H3K4me3 demethylation inhibited IL4i1 transcription. Inhibiting JMJD3 with GSK-J4 can increase IL4i1 expression, subsequently decreasing the expressions of M1 and increasing of M2 in vivo. The over-expression IL4i1 in LPS-stimulated macrophage or inhibiting JMJD3 with GSK-J4 can both reverse the increase of the macrophage M1/M2 ratio in vitro. C/EBPβ and KDM5A were upregulated by LPS simulation, which linked JMJD3-induced H3K27-H3K4 demethylation. JMJD3 inhibited IL4i1 to increase the macrophage M1/M2 phenotype ratio and aggravate LPS-induced ALI. Using GSK-J4 to inhibit JMJD3 may facilitate the treatment of LPS-induced ALI.

Molecular signatures distinguish senescent cells from inflammatory cells in aged mouse callus stromal cells

Cellular senescence plays important roles in age-related diseases, including musculoskeletal disorders. Senescent cells (SCs) exert a senescence-associated secretory phenotype (SASP) by producing SASP factors, some of which overlap with factors produced by inflammatory cells (Inf-Cs). However, the differences between SCs and Inf-Cs and how they interact with each other during fracture repair have not been well studied. Here, we analyzed single cell RNA sequencing data of aged mouse fracture callus stromal cells. We defined Inf-Cs as cells that express NF-κB Rela/Relb, SCs as cells that express the senescence genes, Cdkn1a, Cdkn2a or Cdkn2c, and inflammatory SCs (Inf-SCs) as cells that express both NF-κB and senescence genes. Differentially expressed genes and pathway analyses revealed that Inf-SCs and SCs had a similar gene expression profile and upregulated pathways that are related to DNA damage/oxidation-reduction and cellular senescence, while Inf-Cs expressed different gene signatures and pathways from SCs and Inf-SCs, mainly related to inflammation. Cellchat software analysis indicated that SCs and Inf-SCs are potential ligand-producing cells that affect Inf-Cs as target cells. Cell culture experiments demonstrated that SC conditioned medium promoted inflammatory gene expression by callus-derived mesenchymal progenitor cells, and Inf-Cs had reduced osteoblast differentiation capacity. In summary, we have identified three cell subclusters associated with inflammation and senescence in callus stromal cells, predicted potential effects of Inf-SCs and SCs on Inf-Cs by production of active ligands, and demonstrated that when mesenchymal progenitors acquire inflammatory phenotypes their osteogenic potential is reduced.

Overexpression of hepatic pescadillo 1 in obesity induces lipid dysregulation by inhibiting autophagy

Previous studies indicated that increased hepatic pescadillo 1 (PES1) in type II diabetic mice was associated with lipid dysregulation. However, the role of PES1 in obesity-associated lipid dysregulation is still unknown. This study investigates the effects and underlying mechanism. Livers from obese and healthy humans and mice were collected, and C57BL/6J mice were either fed on standard diet or high fat diet (HFD). McArdle 7777 rat hepatoma cells were treated with phosphate-buffered saline and oleic acid (OA)+ palmitic acid (PA), respectively. In vitro Pes1 knockdown or overexpression and in vivo Pes1 knockdown or liver-specific ablation or supplementation of Pes1 were used to explore the modulating role of PES1. We found that obesity in humans enhanced hepatic PES1 protein, accompanied by increased plasma TG. These data are consistent with those from OA+PA-treated cells and from HFD- or Pes1 overexpression-treated C57BL/6J mice. In vitro and in vivo Pes1 knockdown in cultured cells and in ob/ob mice promoted the expression of autophagy markers (TFEB, Beclin1 and LC3B-Ⅱ) while decreasing p62 and TG, contrary to Pes1 overexpression in cells and in normal mice. Moreover, liver-specific knockout of Pes1 protected the mice fed on HFD from increased TG levels, facilitating the TFEB, Beclin1 and LC3B-Ⅱ and curbing p62. Mechanistically, OA+PA increased C/EBPβ binding to the Pes1 promoter, leading to the elevation of PES1, and subsequently enhancing PES1-facilitated ubiquitination of TFEB. Our findings reveal that overexpression of hepatic PES1 in obesity may induce TG dysregulation by inhibiting autophagy.

Diversity and heterogeneity in human breast cancer adipose tissue revealed at single-nucleus resolution

Introduction

There is increasing awareness of the role of adipose tissue in breast cancer occurrence and development, but no comparison of adipose adjacent to breast cancer tissues and adipose adjacent to normal breast tissues has been reported.

Methods

Single-nucleus RNA sequencing (snRNA-seq) was used to analyze cancer-adjacent and normal adipose tissues from the same breast cancer patient to characterize heterogeneity. SnRNA-seq was performed on 54513 cells from six samples of normal breast adipose tissue (N) distant from the tumor and tumor-adjacent adipose tissue (T) from the three patients (all surgically resected).

Results and discussion

Significant diversity was detected in cell subgroups, differentiation status and, gene expression profiles. Breast cancer induces inflammatory gene profiles in most adipose cell types, such as macrophages, endothelial cells, and adipocytes. Furthermore, breast cancer decreased lipid uptake and the lipolytic phenotype and caused a switch to lipid biosynthesis and an inflammatory state in adipocytes. The in vivo trajectory of adipogenesis revealed distinct transcriptional stages. Breast cancer induced reprogramming across many cell types in breast cancer adipose tissues. Cellular remodeling was investigated by alterations in cell proportions, transcriptional profiles and cell-cell interactions. Breast cancer biology and novel biomarkers and therapy targets may be exposed.

Gene profiling reveals the role of inflammation, abnormal uterine muscle contraction and vascularity in recurrent implantation failure

Objective: Recurrent implantation failure (RIF) is now disturbing numerous infertile couples accepting assisted reproductive technology (ART). And the endometrial factors are crucial causes of recurrent implantation failure. However, its mechanism is still unclear. Thus, the aim of this study is to identify altered biologic processes in endometrium that may contribute to recurrent implantation failure. Methods: We recruited two microarray datasets (GSE103465, GSE111974) from Gene Expression Omnibus database (GEO), which contain endometrium from RIF and normal women during implantation period. Using the online tools GEO2R and Venny, we identified Differentially Expressed Genes (DEGs) of selected datasets, and obtained common DEGs. Gene Ontology (GO) terms, Kyoto Encyclopedia of Genes and Genomes (KEGG) and BioCatar pathway enrichment were conducted with Enrichr platform, "ssgsea" and "ggplot2" package of RStudio. PPI networks and hub gene related TF-gene interaction and TF-miRNA co-regulation networks were built via online tools STRING and NetworkAnalyst. Immune infiltration analysis was performed by CIBERSORT platform. Recurrent implantation failure subgroup identification was achieved through "ConsensusClusterPlus," "tsne," "ssgsea", and "ggpubr" package in RStudio. Diagnostic characteristic ROC curves were constructed via "pROC" and "ggplot2" package of RStudio. Enrichr platform was utilized to find drugs targeting hub genes. Results: 26 common DEGs were confirmed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes/BioCarta analysis determined common DEGs were mainly enriched in inflammation associated pathways including TNF, NF-κB, IL-4, IL-10, IL-6, and TGF-β signaling pathways. Five hub genes (PTGS2, VCAM1, EDNRB, ACTA2, and LIF) and related TF-gene and TF-miRNA interactions were identified. Immune infiltration analysis indicated the importance of macrophage M2 in recurrent implantation failure patients. Importantly, subgroup identification analysis highlighted that recurrent implantation failure patients can be divided into two subgroups with different phenotypes. Moreover, the ROC curves and drugs may provide new diagnostic and therapeutic thought for recurrent implantation failure.

H3K27 tri-demethylase JMJD3 inhibits macrophage apoptosis by promoting ADORA2A in lipopolysaccharide-induced acute lung injury

Acute lung injury (ALI) is a common critical disease, which is characterized by an uncontrolled, acute inflammatory response, diffuse lung damage and ultimately directly deteriorates into acute respiratory distress syndrome. The number of pro-inflammatory macrophages is related to the severity of ALI. Up-regulation of lipopolysaccharide (LPS)-activated macrophage apoptosis can reduce the pro-inflammatory reactions. Jumonji domain-containing protein D3 (JMJD3)-mediated histone 3 lysine 27 trimethylation (H3K27me3) demethylation may promote the pro-inflammatory response of macrophages under LPS stimulation. However, the mechanism of JMJD3 affecting macrophage apoptosis is still not clear. To explore this gap in knowledge, the ALI mice model with intratracheal administration of LPS and RAW264.7 cells with LPS stimulation were used as in vivo and in vitro experiments. The expression of JMJD3 and H3K27me3 and their cellular localization were analysed in lung tissue. Apoptosis was evaluated using TUNEL staining and flow cytometry. Expression of H3K27me3, ADORA2A and C/EBPβ were compared among different treatments and chromatin immunoprecipitation was performed to investigate the regulatory relationship. Our study showed that JMJD3 expression was upregulated in LPS-induced ALI mice and RAW264.7 cells. JMJD3-indued H3K27me3 demethylation inhibited caspase-3 cleavage by upregulating ADORA2A to decrease LPS-stimulated macrophage apoptosis and promoted the inflammatory reaction. This H3K27me3 demethylation also increased C/EBPβ expression, which may enhance ADORA2A expression further. Besides, inhibiting ADORA2A can also promote LPS-limited macrophage apoptosis. Moreover, the inhibition of JMJD3 in vivo and in vitro relieved the inhibition of macrophage apoptosis thus leading to the resolution of the inflammation. JMJD3 might inhibit macrophage apoptosis by promoting ADORA2A expression in LPS-induced ALI.

Toxic effects of trace phenol/guanidine isothiocyanate (P/GI) on cells cultured nearby in covered 96-well plates

BACKGROUND

A mixture of phenol and guanidine isothiocyanate ("P/GI", the principal components of TRIzol™ and similar products) is routinely used to isolate RNA, DNA, and proteins from a single specimen. In time-course experiments of cells grown in tissue culture, replicate wells are often harvested sequentially and compared, with the assumption that in-well lysis and complete aspiration of P/GI has no effect on continuing cultures in nearby wells.

METHODS

To test this assumption, we investigated morphology and function of RAW 264.7 cells (an immortalized mouse macrophage cell line) cultured in covered 96-well plates for 4, 8, or 24 h at varying distances from a single control well or a well into which P/GI had been deposited and immediately aspirated completely.

RESULTS

Time- and distance-dependent disruptions resulting from proximity to a single well containing trace residual P/GI were seen in cell morphology (blebbing, cytoplasmic disruption, and accumulation of intracellular vesicles), cell function (pH of culture medium), and expression of genes related to inflammation (Tnfα) and autophagy (Lc3b). There was no transcriptional change in the anti-apoptotic gene Mcl1, nor the pro-apoptotic gene Hrk, nor in P/GI-unexposed control cultures. LPS-stimulated cells incubated near P/GI had lower expression of the cytokine Il6. These effects were seen as early as 4 h of exposure and at a distance of up to 3 well units from the P/GI-exposed well.

CONCLUSIONS

Exposure to trace residual quantities of P/GI in covered tissue culture plates leads to substantial disruption of cell morphology and function in as little as 4 h, possibly through induction of autophagy but not apoptosis. This phenomenon should be considered when planning time-course experiments in multi-well covered tissue culture plates.

Inhibition of CEBPB Attenuates Lupus Nephritis via Regulating Pim-1 Signaling

Systemic lupus erythematosus (SLE) is an autoimmune disease leading to inflammatory damage in multiple target organs, and lupus nephritis (LN) is one of the most life-threatening organ manifestations. CCAAT/enhancer-binding protein β (CEBPB) regulates the NLRP3 inflammasome and is involved in the pathogenesis of SLE. However, the role and mechanism of CEBPB in LN remains unclear. MRL/lpr mice and lipopolysaccharides (LPS) combined with adenosine triphosphate- (ATP-) treated glomerular podocytes were used as models of LN in vivo and in vitro, respectively. In vivo, we investigated the expressions of CEBPB during the development of MRL/lpr mice. Then we assessed the effect of CEBPB inhibition on renal structure and function through injecting shCEBPB lentivirus into MRL/lpr mice. In vitro, glomerular podocytes were treated with Pim-1-OE and siCEBPB to explore the relation between CEBPB and Pim-1. The progression of LN in mice was associated with the increased level of CEBPB, and the inhibition of CEBPB ameliorated renal structure impairments and improved renal function damage associated with LN. Knockdown of CEBPB could suppress the activation of NLRP3 inflammasome and the secretion of IL-1β and IL-6. Furthermore, the knockdown of CEBPB could inhibit NLRP3 inflammasome activation and pyroptosis via binding to Pim-1 promoter to downregulate its expression, and the overexpression of Pim-1 reversed the effects of CEBPB deficiency. The regulation of CEBPB on Pim-1 facilitated pyroptosis by activating NLRP3 inflammasome, thereby promoting the development of LN.

New insights into macrophage subsets in atherosclerosis

Macrophages in atherosclerotic patients are notably plastic and heterogeneous. Single-cell RNA sequencing (Sc RNA-seq) can provide information about all the RNAs in individual cells, and it is used to identify cell subpopulations in atherosclerosis (AS) and reveal the heterogeneity of these cells. Recently, some findings from Sc RNA-seq experiments have suggested the existence of multiple macrophage subsets in atherosclerotic plaque lesions, and these subsets exhibit significant differences in their gene expression levels and functions. These cells affect various aspects of plaque lesion development, stabilization, and regression, as well as plaque rupture. This article aims to review the content and results of current studies that used RNA-seq to explore the different types of macrophages in AS and the related molecular mechanisms as well as to identify the potential roles of these macrophage types in the pathogenesis of atherosclerotic plaques. Also, this review listed some new therapeutic targets for delaying atherosclerotic lesion progression and treatment based on the experimental results.

Effect of erythromycin on the ultrastructure of human macrophages exposed to cigarette smoke extract in vitro

Macrophages serve an active role in the pathophysiology of chronic obstructive pulmonary disease (COPD). Erythromycin (EM) has been verified as an effective treatment for COPD. However, there are few studies on the effect of EM on the ultrastructure of macrophages exposed to cigarette smoke extract (CSE). In the present study, human macrophages were randomly divided into three groups: The control, CSE and the CSE+EM group, using electron microscopy, the effect of EM was evaluated by comparing the ultrastructural changes between these groups. The macrophages were additionally divided into a further four groups: The control, CSE, CSE+EM 24 h and CSE+EM 48 h groups. The generation of reactive oxygen species (ROS) in each group was evaluated by detecting fluorescence intensity. It was observed that the cellular ultrastructure of the CSE group exhibited abnormal changes, though this effect was reversed back to the level of the control in the CSE+EM group. Compared with the control group, the ROS expression level was significantly increased in the CSE group (P < .05); however, compared with the CSE group, the ROS concentration was decreased in the CSE+EM 24 h (P < .05) and CSE+EM 48 h groups (P < .05), though this was more apparent in the EM 48 h group. It was concluded that EM protects human macrophages against CSE. Moreover, it was hypothesized that EM may reduce the symptoms of patients with COPD by protecting the macrophage ultrastructure from the effects of CSE, resulting in the decreased generation of ROS, inhibiting autophagy and reducing endoplasmic reticulum stress.

Bushen Jieyu Tiaochong Formula reduces apoptosis of granulosa cells via the PERK-ATF4-CHOP signaling pathway in a rat model of polycystic ovary syndrome with chronic stress

ETHNOPHARMACOLOGICAL RELEVANCE

Polycystic ovary syndrome (PCOS) is a common and complex endocrine disorder that is also an important cause of infertility. Adverse psychological stress can aggravate the occurrence and development of PCOS. Bushen Jieyu Tiaochong Formula (BJTF), a prescription of Traditional Chinese Medicine (TCM), has been used in the treatment of PCOS and shown to be effective in reducing negative emotion. However, the therapeutic mechanism has yet to be clearly elucidated. In the current study, we investigated the potential mechanism of action of BJTF.

AIM OF THE STUDY

To investigate the role of PERK-ATF4-CHOP signaling in the molecular mechanisms that mediate the effects of BJTF in a rat model of PCOS, with chronic stress induced by letrozole and a chronic unpredictable mild stress (CUMS) paradigm.

MATERIALS AND METHODS

In addition to the normal control group, the PCOS combined with CUMS model rats were randomly assigned to a model group, a Diane-35 (ethinylestradiol 35 μg/cyproterone acetate 2 mg)-treated positive control group, or one of three BJTF-treated groups receiving a low, medium, or high dose. Behavioral testing, including the sucrose preference test and open field test, was conducted, and hematoxylin and eosin (H&E) staining was used to observe changes in the pathological morphology of ovarian tissue. Free testosterone (FT), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels in serum were quantified by enzyme-linked immunosorbent assays (ELISA). The hippocampal levels of norepinephrine (NE), 5-hydroxytryptamine/serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) were measured using high-performance liquid chromatography-electrochemical detection (HPLC-ECD). Apoptotic granulosa cells were detected using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry were used to detect the expression of glucose-regulated protein 78 (GRP78) and CHOP in the ovarian tissues. The expression levels of GRP78, CHOP, PERK, and ATF4 in ovarian tissues were also measured by western blotting.

RESULTS

Treatment with either BJTF or Diane-35 ameliorated the abnormal cystic dilatation of follicles in the model rats and reduced the serum levels of FT and LH, and the LH/FSH ratio. BJTF treatment also attenuated chronic psychological stress-like behavior and regulated the expression and metabolism of cerebral monoamine neurotransmitters. The efficacy of BJTF was greater than that of Diane-35, with the optimal effects observed at the medium dose. BJTF also lowered the apoptotic index of ovarian granulosa cells and downregulated the expression of GRP78, CHOP, and ATF4. Although the expression level of PERK was not significantly altered by BJTF, the mean PERK expression level was the lowest in the medium-dose BJTF group.

CONCLUSIONS

Administration of BJTF has the therapeutic potential to promote the homeostasis of the reproductive endocrine environment and to restore follicular development and ovulation, possibly through the inhibition of the PERK-ATF4-CHOP signaling pathway, leading to downregulation of GRP78 expression to further delay ovarian granule cell apoptosis mediated by endoplasmic reticulum stress (ERS). Moreover, BJTF could improve behavioral performance by regulating cerebral monoamine neurotransmitters in this rat model. These findings provide a new perspective for treating PCOS related to psychological stress using TCM.

Understanding the Underlying Molecular Mechanisms of Meiotic Arrest during In Vitro Spermatogenesis in Rat Prepubertal Testicular Tissue

In vitro spermatogenesis appears to be a promising approach to restore the fertility of childhood cancer survivors. The rat model has proven to be challenging, since germ cell maturation is arrested in organotypic cultures. Here, we report that, despite a meiotic entry, abnormal synaptonemal complexes were found in spermatocytes, and in vitro matured rat prepubertal testicular tissues displayed an immature phenotype. RNA-sequencing analyses highlighted up to 600 differentially expressed genes between in vitro and in vivo conditions, including genes involved in blood-testis barrier (BTB) formation and steroidogenesis. BTB integrity, the expression of two steroidogenic enzymes, and androgen receptors were indeed altered in vitro. Moreover, most of the top 10 predicted upstream regulators of deregulated genes were involved in inflammatory processes or immune cell recruitment. However, none of the three anti-inflammatory molecules tested in this study promoted meiotic progression. By analysing for the first time in vitro matured rat prepubertal testicular tissues at the molecular level, we uncovered the deregulation of several genes and revealed that defective BTB function, altered steroidogenic pathway, and probably inflammation, could be at the origin of meiotic arrest.

Astragaloside IV protects against C/EBP homologous protein-mediated apoptosis in oxidized low-density lipoprotein-treated macrophages by promoting autophagy

Astragaloside Ⅳ (AS-Ⅳ) is one of the main active components extracted from Astragalus membranaceus that exerts an antiatherosclerotic effect. Our study explored the underlying anti-apoptotic effects and the mechanisms of action of AS-Ⅳ in oxidized low-density lipoprotein (oxLDL)-stimulated macrophages and in vulnerable plaques. The results showed that AS-Ⅳ lowered the oxLDL-induced lipid content and reversed the oxLDL-induced reduction in cell viability and elevation in lactate dehydrogenase (LDH) leakage and apoptosis in RAW264.7 macrophages, similar to the effects of 4-phenylbutyric acid (PBA, an ER stress inhibitor). In addition, consistent with the effect exerted by PBA, AS-Ⅳ inhibited oxLDL-triggered ER stress activation by decreasing the level of inositol-requiring enzyme1 phosphorylation and transcription factor 6 nuclear translocation and upregulating the protein and mRNA expression of glucose-regulated protein 78 (GPR78) and C/EBP homologous protein (CHOP). As expected, autophagy activation was induced by AS-IV, evidenced by increased expression of microtubule-associated protein 1 light chain 3-Ⅱ (LC3-Ⅱ), autophagy-related gene 5, and beclin-1 in macrophages. Furthermore, after pretreatment with 3-methyladenine and beclin-1 small interfering RNA, the inhibitory role played by AS-Ⅳ in oxLDL-induced ER stress-CHOP-mediated macrophage apoptosis was weakened, while its inhibitory effect was further enhanced by rapamycin pretreatment. Moreover, administration of AS-Ⅳ or rapamycin to Apoe^-/- mice upregulated LC3-Ⅱ expression and collagen content but decreased CHOP expression, macrophage apoptosis, and lipid areas. Overall, by promoting autophagy, AS-Ⅳ effectively protects macrophages from oxLDL-induced apoptosis mediated by ER stress-CHOP, which may reinforce the stability of atherosclerotic plaques.

Identification of Regulatory Factors and Prognostic Markers in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive degeneration of motor neurons, leading to muscle atrophy, paralysis and even death. Immune disorder, redox imbalance, autophagy disorder, and iron homeostasis disorder have been shown to play critical roles in the pathogenesis of ALS. However, the exact pathogenic genes and the underlying mechanism of ALS remain unclear. The purpose of this study was to screen for pathogenic regulatory genes and prognostic markers in ALS using bioinformatics methods. We used Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, gene set enrichment analysis (GSEA), and expression regulation network analysis to investigate the function of differentially expressed genes in the nerve tissue, lymphoid tissue, and whole blood of patients with ALS. Our results showed that the up-regulated genes were mainly involved in immune regulation and inflammation, and the down-regulated genes were mainly involved in energy metabolism and redox processes. Eleven up-regulated transcription factors (CEBPB, CEBPD, STAT5A, STAT6, RUNX1, REL, SMAD3, GABPB2, FOXO1, PAX6, and FOXJ1) and one down-regulated transcription factor (NOG) in the nerve tissue of patients with ALS likely play important regulatory roles in the pathogenesis of ALS. Based on construction and evaluation of the ALS biomarker screening model, cluster analysis of the identified characteristic genes, univariate Cox proportional hazards regression analysis, and the random survival forest algorithm, we found that MAEA, TPST1, IFNGR2, and ALAS2 may be prognostic markers regarding the survival of ALS patients. High expression of MAEA, TPST1, and IFNGR2 and low expression of ALAS2 in ALS patients may be closely related to short survival of ALS patients. Taken together, our results indicate that immune disorders, inflammation, energy metabolism, and redox imbalance may be the important pathogenic factors of ALS. CEBPB, CEBPD, STAT5A, STAT6, RUNX1, REL, SMAD3, GABPB2, FOXO1, PAX6, FOXJ1, and NOG may be important regulatory factors linked to the pathogenesis of ALS. MAEA, TPST1, IFNGR2, and ALAS2 are potential important ALS prognostic markers. Our findings provide evidence on the pathogenesis of ALS, potential targets for the development of new drugs for ALS, and important markers for predicting ALS prognosis.

Short-Chain Fatty Acid Decreases the Expression of CEBPB to Inhibit miR-145-Mediated DUSP6 and Thus Further Suppresses Intestinal Inflammation

Intestinal inflammation is a common disease which can further lead to inflammatory bowel disease and even intestinal cancer. The increasing focus has come to the role of short-chain fatty acid (SCFA) in various bowel diseases. Hence, this study was designed to explore the specific role of SCFA in intestinal inflammation. In vivo and in vitro models of intestinal inflammation were constructed by lipopolysaccharide (LPS) injection in mice and LPS treatment on intestinal epithelial cells. A possible regulatory mechanism involving SCFA, CCAAT enhancer-binding protein beta (CEBPB), microRNA-145 (miR-145), and dual-specificity phosphatase 6 (DUSP6) in intestinal inflammation was verified by ChIP assay and dual-luciferase reporter gene assay. To evaluate the effects of SCFA on LPS-treated intestinal epithelial cells, the expression of relevant genes and inflammatory factors (IL-6, TNF-α, and IL-1β) were determined. Last, the role of SCFA in vivo was explored through the scoring of disease activity index (DAI) and observation of colonic histology of LPS-treated mice. SCFA decreased the CEBPB expression in mouse colon tissues and small intestine epithelial cells induced by LPS. Furthermore, CEBPB could bind to the miR-145 promoter to inhibit its expression, thereby promoting the expression of DUSP6. In addition, SCFA improved the DAI, colonic histology, and the expression of serum inflammatory factors in LPS-treated mice and cells, noting that SCFA alleviated intestinal inflammation in vitro and in vivo. To sum up, SCFA inhibited DUSP6 by upregulating miR-145 through CEBPB repression and thus prevented the development of intestinal inflammation.

LKB1 Regulates Vascular Macrophage Functions in Atherosclerosis

Liver kinase B1 (LKB1) is known to shape the regulation of macrophage function by participating in multiple processes including cell metabolism, growth, and polarization. However, whether LKB1 also affects the functional plasticity of macrophages in atherosclerosis has not attracted much attention. Abnormal macrophage function is a pathophysiological hallmark of atherosclerosis, characterized by the formation of foam cells and the maintenance of vascular inflammation. Mounting evidence supports that LKB1 plays a vital role in the regulation of macrophage function in atherosclerosis, including affecting lipid metabolism reprogramming, inflammation, endoplasmic reticulum stress, and autophagy in macrophages. Thus, decreased expression of LKB1 in atherosclerosis aggravates vascular injury by inducing excessive lipid deposition in macrophages and the formation of foam cells. To systematically understand the role and potential mechanism of LKB1 in regulating macrophage functions in atherosclerosis, this review summarizes the relevant data in this regard, hoping to provide new ideas for the prevention and treatment of atherosclerosis.

Renal Cellular Autophagy in Obesity: Boon or Bane?

Obesity is a growing human health concern worldwide and imposes adverse effects on many cell types and organ systems, including the kidneys. Obesity interferes with various cellular processes by increasing lipid accumulation and oxidation, insulin resistance, and inflammation. Autophagy is an important cellular process to maintain hemostasis and preserve resources, but might be altered in obesity. Interestingly, experimental studies have shown either an increase or a decrease in the rate of autophagy, and accumulation of byproducts and mediators of this cascade in kidneys of obese individuals. Hence, whether autophagy is beneficial or detrimental under these conditions remains unresolved. This review summarizes emerging evidence linking superfluous fat accumulation to alterations in autophagy. Elucidating the role of autophagy in the pathogenesis and complications of obesity in the kidney might help in the identification of therapeutic targets to prevent or delay the development of chronic kidney disease in obese subjects. Autophagy, kidney, obesity, lipids.

Danlou Tablets Inhibit Atherosclerosis in Apolipoprotein E-Deficient Mice by Inducing Macrophage Autophagy: The Role of the PI3K-Akt-mTOR Pathway

Atherosclerosis (AS) is a type of chronic vascular disease, and its etiology is not yet fully understood. AS is characterized by lipid deposition, atherosclerotic plaque formation, vascular stenosis or even complete blockage of the blood vessel wall. Clinical studies have shown that Danlou tablets (DLTs) can improve the heart function, quality of life, and prognosis of patients with coronary heart disease and myocardial infarction. However, its mechanism of action remains unknown. Our study revealed that DLTs ameliorated ApoE^−/−AS mouse aortic atherosclerotic plaques [hematoxylin-eosin (HE) staining and small animal ultrasound] and reduced CD68⁺ macrophage infiltration, the expression of the inflammatory factor interferon-gamma (IFN-γ), vascular smooth muscle α-actin, and serum lipid levels. In vitro, in the macrophage foaming model, DLTs partially restored the activity of RAW264.7 cells, reduced the uptake of lipid droplets, and inhibited lipid droplet accumulation and apoptosis within BMDMs. We also found that Torin1, an autophagy agonist, reduced intracellular lipid deposition in BMDMs, as did DLTs. Moreover, DLTs upregulated the expression of the autophagy-related protein LC3II and decreased p62 accumulation in RAW264.7 cells. DLTs also inhibited the phosphorylation of p-PI3K, p-Akt, and p-mTOR, leading to upregulated autophagy in RAW264.7 cells. In summary, our results suggested that DLTs can promote autophagy in macrophages by inhibiting the PI3K/Akt/mTOR signaling pathway, thereby reducing foam cell formation and improving atherosclerosis.

Lipid metabolism, inflammation, and foam cell formation in health and metabolic disorders: targeting mTORC1

Metabolic homeostasis is important for maintaining a healthy lifespan. Lipid metabolism is particularly necessary for the maintenance of metabolic energy sources and their storage, and the structure and function of cell membranes, as well as for the regulation of nutrition through lipogenesis, lipolysis, and lipophagy. Dysfunctional lipid metabolism leads to the development of metabolic disorders, such as atherosclerosis, diabetes mellitus, and non-alcoholic fatty liver disease (NAFLD). Furthermore, dyslipidaemia causes inflammatory responses and foam cell formation. Mechanistic target of rapamycin (mTOR) signalling is a key regulator of diverse cellular processes, including cell metabolism and cell fate. mTOR complex 1 (mTORC1) is involved in lipid metabolism and immune responses in the body. Therefore, the mTORC1 signalling pathway has been suggested as a potential therapeutic target for the treatment of metabolic disorders. In this review, we focus on the roles of mTORC1 in lipid metabolism and inflammation, and present current evidence on its involvement in the development and progression of metabolic disorders.

Evaluation of hepatotoxicity induced by 2-ethylhexyldiphenyl phosphate based on transcriptomics and its potential metabolism pathway in human hepatocytes

Increasing use of organophosphorus flame retardants (OPFRs) has aroused great concern to their uncertain environment risk, especially to human health risk. In our study, hepatotoxicity screening of six aryl-OPFRs, potential hepatotoxicity mechanism of 2-ethylhexyldiphenyl phosphate (EHDPP) using RNA-sequencing and its metabolites were investigated in human hepatocytes (L02). The toxicity results demonstrated that EHDPP should be prioritized for further research with the highest toxicity. Further RNA-seq results through GO and KEGG enrichment analysis indicated that exposure to 10 mg/L of EHDPP significantly affected energy homeostasis, endoplasmic reticulum (ER) stress, apoptosis, cell cycle, and inflammation response in cells. The top 12 hub genes were validated by RT-qPCR and conformed to be mainly related to glycolysis and ER stress, followed by cell cycle and inflammation response. Western blot, apoptosis detection, glycolysis stress test, and cell cycle analysis were further performed to verify the above main pathways. Additionally, it was found in the metabolism experiment that detoxification of EHDPP by phase I and phase II metabolism in cells wasn't significant until 48 h with a metabolic rate of 6.12%. EHDPP was stable and still dominated the induction of toxicity. Overall, this study provided valuable information regarding the toxicity and potential metabolism pathway of EHDPP.

Foxc2 Alleviates Ox-LDL-Induced Lipid Accumulation, Inflammation, and Apoptosis of Macrophage via Regulating the Expression of Angptl2

The present study aimed to investigate the role of Forkhead box protein C2 (Foxc2) in oxidized low-density lipoprotein (ox-LDL)-induced macrophages and identify the potential mechanisms. RAW264.7 cells, the murine macrophage cell line, were stimulated by ox-LDL, and cell proliferation was examined. The levels of inflammation- and oxidative stress-related markers were detected using kits after induction with ox-LDL. Subsequently, the expression of Foxc2 was measured using Western blotting. After transfection with Foxc2 pcDNA3.1, intracellular lipid droplets were examined using oil red O staining. The levels of total cholesterol (TC), free cholesterol (FC), inflammatory cytokines, and oxidative stress markers were determined. Moreover, apoptosis of RAW264.7 cells was detected using flow cytometry, and apoptosis-related proteins were measured using Western blotting. Angiopoietin-like protein 2 (Angptl2) was predicted as a target gene of Foxc2. Therefore, the expression of Angptl2 was examined after Foxc2 overexpression in ox-LDL-induced RAW264.7 cells. Then, the changes of intracellular lipid droplets, TC, FC, inflammatory cytokines, oxidative stress factors, and cell apoptosis were detected after Angptl2 overexpression or co-transfection with Foxc2 and Angptl2 pcDNA3.1. The results revealed that ox-LDL induction inhibited proliferation of RAW264.7 cells and promoted the release of inflammatory factors. Importantly, the expression of Foxc2 was obviously decreased after stimulation by ox-LDL. Foxc2 overexpression suppressed lipid accumulation, TC, FC levels, inflammation, oxidative stress, and apoptosis induced by ox-LDL, whereas these inhibitory effects were relieved after co-transfection with Angptl2 pcDNA3.1. These findings demonstrated that Foxc2 can alleviate ox-LDL-induced lipid accumulation, inflammation, and apoptosis of macrophage via regulating the expression of Angptl2.

Pathological Crosstalk Between Oxidized LDL and ER Stress in Human Diseases: A Comprehensive Review

The oxidative modification of the major cholesterol carrying lipoprotein, oxLDL, is a biomarker as well as a pathological factor in cardiovascular diseases (CVD), type 2 diabetes mellitus (T2DM), obesity and other metabolic diseases. Perturbed cellular homeostasis due to physiological, pathological and pharmacological factors hinder the proper functioning of the endoplasmic reticulum (ER), which is the major hub for protein folding and processing, lipid biosynthesis and calcium storage, thereby leading to ER stress. The cellular response to ER stress is marked by a defensive mechanism called unfolded protein response (UPR), wherein the cell adapts strategies that favor survival. Under conditions of excessive ER stress, when the survival mechanisms fail to restore balance, UPR switches to apoptosis and eliminates the defective cells. ER stress is a major hallmark in metabolic syndromes such as diabetes, non-alcoholic fatty liver disease (NAFLD), neurological and cardiovascular diseases. Though the pathological link between oxLDL and ER stress in cardiovascular diseases is well-documented, its involvement in other diseases is still largely unexplored. This review provides a deep insight into the common mechanisms in the pathogenicity of diseases involving oxLDL and ER stress as key players. In addition, the potential therapeutic intervention of the targets implicated in the pathogenic processes are also explored.

Evodiamine Enhanced the Anti-Inflammation Effect of Clindamycin in the BEAS-2B Cells Infected with H5N1 and Pneumoniae D39 Through CREB-C/EBPβ Signaling Pathway

Pneumonia is a pulmonary disease among children. Evodiamine, a traditional Chinese medicine, is known for anti-inflammatory effect. This study aimed to investigate the impact of evodiamine on severe pneumonia-like cells and the underlying mechanism involved. H5N1 and pneumoniae D39 was used to induce severe pneumonia-like conditions in BEAS-2B cells. The cell viability in BEAS-2B cells after treatments with 0, 20, 40, 60, 80, and 100 μM evodiamine was examined using MTT assays. The protein concentrations of inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β, and Toll-like receptors (TLRs) were measured by enzyme-linked immunosorbent assay methods and the protein and mRNA changes in C/EBPβ/CREB were measured using Real Time-quantitative polymerase chain reaction and Western blot methods. Our results revealed that Evodiamine significantly decreased TNF-α, IL-6, and IL-1β in BEAS-2B cells. Moreover, evodiamine markedly reduced TLR2,3,4 protein expression and the phosphorylated protein of C/EBPβ and CREB. Besides, evodiamine combined with clindamycin exerted more significant effects than clindamycin alone. Taken together, our results demonstrated that evodiamine enhanced the anti-inflammation effect of clindamycin in the BEAS-2B cells infected with H5N1 and pneumoniae D39 through CREB-C/EBPβ signaling pathway.

Role of macrophage autophagy in atherosclerosis: modulation by bioactive compounds

Atherosclerosis is a chronic inflammatory disease associated with lipid metabolism disorder. Autophagy is a catabolic process and contributes to maintaining cellular homeostasis. Substantial evidence suggests that defective autophagy is implicated in several diseases, including atherosclerosis, while increased autophagy mitigates atherosclerosis development. Thus, understanding the mechanisms of autophagy regulation and its association with atherosclerosis is vital to develop new therapies against atherosclerosis. Dietary bioactive compounds are non-nutrient natural compounds that include phenolics, flavonoids, and carotenoids. Importantly, these bioactive compounds possess anti-inflammatory, antioxidant, and antibacterial properties that may alleviate various chronic diseases. Recently, examining the effects of bioactive compounds on autophagy activity in atherogenesis has drawn considerable attention. The current review discusses the role of macrophage autophagy in the development and progression of atherosclerosis. We also summarize our current knowledge of the therapeutic potential of bioactive compounds on atherosclerosis and autophagy.

Endoplasmic reticulum stress and unfolded protein response in cardiovascular diseases

Cardiovascular diseases (CVDs), such as ischaemic heart disease, cardiomyopathy, atherosclerosis, hypertension, stroke and heart failure, are among the leading causes of morbidity and mortality worldwide. Although specific CVDs and the associated cardiometabolic abnormalities have distinct pathophysiological and clinical manifestations, they often share common traits, including disruption of proteostasis resulting in accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER). ER proteostasis is governed by the unfolded protein response (UPR), a signalling pathway that adjusts the protein-folding capacity of the cell to sustain the cell's secretory function. When the adaptive UPR fails to preserve ER homeostasis, a maladaptive or terminal UPR is engaged, leading to the disruption of ER integrity and to apoptosis. ER stress functions as a double-edged sword, with long-term ER stress resulting in cellular defects causing disturbed cardiovascular function. In this Review, we discuss the distinct roles of the UPR and ER stress response as both causes and consequences of CVD. We also summarize the latest advances in our understanding of the importance of the UPR and ER stress in the pathogenesis of CVD and discuss potential therapeutic strategies aimed at restoring ER proteostasis in CVDs.

Long-Term Effects of Very Low Dose Particle Radiation on Gene Expression in the Heart: Degenerative Disease Risks

Compared to low doses of gamma irradiation (γ-IR), high-charge-and-energy (HZE) particle IR may have different biological response thresholds in cardiac tissue at lower doses, and these effects may be IR type and dose dependent. Three- to four-month-old female CB6F1/Hsd mice were exposed once to one of four different doses of the following types of radiation: γ-IR ¹³⁷Cs (40-160 cGy, 0.662 MeV), ¹⁴Si-IR (4-32 cGy, 260 MeV/n), or ²²Ti-IR (3-26 cGy, 1 GeV/n). At 16 months post-exposure, animals were sacrificed and hearts were harvested and archived as part of the NASA Space Radiation Tissue Sharing Forum. These heart tissue samples were used in our study for RNA isolation and microarray hybridization. Functional annotation of twofold up/down differentially expressed genes (DEGs) and bioinformatics analyses revealed the following: (i) there were no clear lower IR thresholds for HZE- or γ-IR; (ii) there were 12 common DEGs across all 3 IR types; (iii) these 12 overlapping genes predicted various degrees of cardiovascular, pulmonary, and metabolic diseases, cancer, and aging; and (iv) these 12 genes revealed an exclusive non-linear DEG pattern in ¹⁴Si- and ²²Ti-IR-exposed hearts, whereas two-thirds of γ-IR-exposed hearts revealed a linear pattern of DEGs. Thus, our study may provide experimental evidence of excess relative risk (ERR) quantification of low/very low doses of full-body space-type IR-associated degenerative disease development.

Pyroptosis is a critical immune-inflammatory response involved in atherosclerosis

Pyroptosis is a form of programmed cell death activated by various stimuli and is characterized by inflammasome assembly, membrane pore formation, and the secretion of inflammatory cytokines (IL-1β and IL-18). Atherosclerosis-related risk factors, including oxidized low-density lipoprotein (ox-LDL) and cholesterol crystals, have been shown to promote pyroptosis through several mechanisms that involve ion flux, ROS, endoplasmic reticulum stress, mitochondrial dysfunction, lysosomal rupture, Golgi function, autophagy, noncoding RNAs, post-translational modifications, and the expression of related molecules. Pyroptosis of endothelial cells, macrophages, and smooth muscle cells in the vascular wall can induce plaque instability and accelerate atherosclerosis progression. In this review, we focus on the pathogenesis, influence, and therapy of pyroptosis in atherosclerosis and provide novel ideas for suppressing pyroptosis and the progression of atherosclerosis.

Regulation of cellular immunity by activating transcription factor 4

Activating transcription factor 4 (ATF4) is a DNA binding transcription factor belonging to the family of basic Leucine zipper proteins. ATF4 can be activated in response to multiple cellular stress signals including endoplasmic reticulum stress in the event of improper protein folding or oxidative stress because of mitochondrial dysfunction as well as hypoxia. There are multiple downstream targets of ATF4 that can coordinate the regulation between survival and apoptosis of a cell based on time and exposure to stress. ATF4, therefore, has a broad range of control that results in the modulation of immune cells of the innate and adaptive responses leading to regulation of the cellular immunity. Studies provide evidence that ATF4 can regulate immune cells such as macrophages, T cells, B cells, NK cells and dendritic cells contributing to progression of disease. Immune cells can be exposed to stressed environment in the event of a pathogen attack, infection, inflammation, or in the tumor microenvironment leading to increased ATF4 activity to regulate these responses. ATF4 can further control differentiation and maturation of different immune cell types becoming a determinant of effective immune regulation. Additionally, ATF4 has been heavily implicated in rendering effector immune cells dysfunctional that are used to target tumorigenesis. Therefore, there is a need to evaluate where the literature stands in understanding the overall role of ATF4 in regulating cellular immunity to identify therapeutic targets and generalized mechanisms for different disease progressions.

Nuclear P38: Roles in Physiological and Pathological Processes and Regulation of Nuclear Translocation

The p38 mitogen-activated protein kinase (p38MAPK, termed here p38) cascade is a central signaling pathway that transmits stress and other signals to various intracellular targets in the cytoplasm and nucleus. More than 150 substrates of p38α/β have been identified, and this number is likely to increase. The phosphorylation of these substrates initiates or regulates a large number of cellular processes including transcription, translation, RNA processing and cell cycle progression, as well as degradation and the nuclear translocation of various proteins. Being such a central signaling cascade, its dysregulation is associated with many pathologies, particularly inflammation and cancer. One of the hallmarks of p38α/β signaling is its stimulated nuclear translocation, which occurs shortly after extracellular stimulation. Although p38α/β do not contain nuclear localization or nuclear export signals, they rapidly and robustly translocate to the nucleus, and they are exported back to the cytoplasm within minutes to hours. Here, we describe the physiological and pathological roles of p38α/β phosphorylation, concentrating mainly on the ill-reviewed regulation of p38α/β substrate degradation and nuclear translocation. In addition, we provide information on the p38α/β ’s substrates, concentrating mainly on the nuclear targets and their role in p38α/β functions. Finally, we also provide information on the mechanisms of nuclear p38α/β translocation and its use as a therapeutic target for p38α/β-dependent diseases.

Endoplasmic Reticulum Stress in Macrophages: The Vicious Circle of Lipid Accumulation and Pro-Inflammatory Response

The endoplasmic reticulum (ER) stress is an important event in the pathogenesis of different human disorders, including atherosclerosis. ER stress leads to disturbance of cellular homeostasis, apoptosis, and in the case of macrophages, to foam cell formation and pro-inflammatory cytokines production. In atherosclerosis, several cell types can be affected by ER stress, including endothelial cells, vascular smooth muscular cells, and macrophages. Modified low-density lipoproteins (LDL) and cytokines, in turn, can provoke ER stress through different processes. The signaling cascades involved in ER stress initiation are complex and linked to other cellular processes, such as lysosomal biogenesis and functioning, autophagy, mitochondrial homeostasis, and energy production. In this review, we discuss the underlying mechanisms of ER stress formation and the interplay of lipid accumulation and pro-inflammatory response. We will specifically focus on macrophages, which are the key players in maintaining chronic inflammatory milieu in atherosclerotic lesions, and also a major source of lipid-accumulating foam cells.

Interaction between C/EBPβ and RUNX2 promotes apoptosis of chondrocytes during human lumbar facet joint degeneration

The pathophysiological changes in cartilage are a crucial feature of lumbar facet joint (LFJ) degeneration and arthritis. However, the molecular mechanism of human LFJ degeneration remains largely defined. This study aimed to examine the changes in chondrocytes at different stages of degenerative LFJ using hematoxylin and eosin and Safranin O staining. The significant loss of chondrocytes in grades 2 and 3 of LFJs was observed. The expression levels of CCAAT enhancer binding protein β (C/EBPβ), Runt-related transcription factor 2 (RUNX2), and matrix metalloproteinase 13 (MMP13) also increased with the aggravation of degeneration (4.89, 5.77, and 6.3 times by Western blot). In vitro, chondrocytes scraped from the LFJs during surgery were stimulated by interleukin (IL)-1β to establish the injury model. The association of C/EBPβ and RUNX2 with active caspase-3 on chondrocytes was analyzed. The high expression level of C/EBPβ, RUNX2, and MMP13 was consistent with that of caspase-3, which reached a peak after 36 h of stimulation. Immunofluorescence suggested that C/EBPβ, RUNX2, and MMP13 co-labeled with active caspase-3. Moreover, immunoprecipitation data prompted that C/EBPβ was able to interact with RUNX2. The knockdown of C/EBPβ significantly decreased the expression levels of MMP13 and active caspase-3 (2.48 and 2.89 times as detected by Western blot analysis) and inhibited chondrocyte apoptosis, which was further demonstrated using flow cytometry. Taken together, the findings of this study uncovered that C/EBPβ could interact with RUNX2 to induce chondrocyte apoptosis in human LFJ degeneration by regulating the expression of MMP13.