Nuclear actin assembly is an integral part of decidualization in human endometrial stromal cells.

Decidualization of the human endometrium is critical for establishing pregnancy and is entailed by differentiation of endometrial stromal cells (ESCs) into decidual cells. During decidualization, the actin cytoskeleton is dynamically reorganized for the ESCs' morphological and functional changes. Although actin dynamically alters its polymerized state upon external stimuli not only in the cytoplasm, but also in the nucleus, nuclear actin dynamics during decidualization have not been elucidated. Here, we show that nuclear actin was specifically assembled during decidualization of human ESCs. This decidualization-specific formation of nuclear actin filaments was disassembled following the withdrawal of the decidualization stimulus, suggesting its reversible process. Mechanistically, RNA-seq analyses revealed that the forced disassembly of nuclear actin resulted in the suppression of decidualization, accompanied with the abnormal upregulation of cell proliferation genes, leading to incomplete cell cycle arrest. CCAAT/enhancer-binding protein beta (C/EBPß), an important regulator for decidualization, was responsible for downregulation of the nuclear actin exporter, thus accelerating nuclear actin accumulation and its assembly for decidualization. Taken together, we demonstrate that decidualization-specific nuclear actin assembly induces cell cycle arrest for establishing the decidualized state of ESCs. We propose that not only the cytoplasmic actin, but also nuclear actin dynamics profoundly affect decidualization process in humans for ensuring pregnancy.

The CEBPB+ glioblastoma subcluster specifically drives the formation of M2 tumor-associated macrophages to promote malignancy growth.

Rationale: The heterogeneity of tumor cells within the glioblastoma (GBM) microenvironment presents a complex challenge in curbing GBM progression. Understanding the specific mechanisms of interaction between different GBM cell subclusters and non-tumor cells is crucial. Methods: In this study, we utilized a comprehensive approach integrating glioma single-cell and spatial transcriptomics. This allowed us to examine the molecular interactions and spatial localization within GBM, focusing on a specific tumor cell subcluster, GBM subcluster 6, and M2-type tumor-associated macrophages (M2 TAMs). Results: Our analysis revealed a significant correlation between a specific tumor cell subcluster, GBM cluster 6, and M2-type TAMs. Further in vitro and in vivo experiments demonstrated the specific regulatory role of the CEBPB transcriptional network in GBM subcluster 6, which governs its tumorigenicity, recruitment of M2 TAMs, and polarization. This regulation involves molecules such as MCP1 for macrophage recruitment and the SPP1-Integrin αvß1-Akt signaling pathway for M2 polarization. Conclusion: Our findings not only deepen our understanding of the formation of M2 TAMs, particularly highlighting the differential roles played by heterogeneous cells within GBM in this process, but also provided new insights for effectively controlling the malignant progression of GBM.

C/EBPß deletion in macrophages impairs mammary gland alveolar budding during the estrous cycle.

Macrophages have important roles in mammary gland development and tissue homeostasis, but the specific mechanisms that regulate macrophage function need further elucidation. We have identified C/EBPß as an important transcription factor expressed by multiple macrophage populations in the normal mammary gland. Mammary glands from mice with C/EBPß-deficient macrophages (Cebpb ΔM) show a significant decrease in alveolar budding during the diestrus stage of the reproductive cycle, whereas branching morphogenesis remains unchanged. Defects in alveolar budding were found to be the result of both systemic hormones and local macrophage-directed signals. RNA sequencing shows significant changes in PR-responsive genes and alterations in the Wnt landscape of mammary epithelial cells of Cebpb ΔM mice, which regulate stem cell expansion during diestrus. Cebpb ΔM macrophages demonstrate a shift from a pro-inflammatory to a tissue-reparative phenotype, and exhibit increased phagocytic capacity as compared to WT. Finally, Cebpb ΔM macrophages down-regulate Notch2 and Notch3, which normally promote stem cell expansion during alveolar budding. These results suggest that C/EBPß is an important macrophage factor that facilitates macrophage-epithelial crosstalk during a key stage of mammary gland tissue homeostasis.

Genetic disruption of ATAT1 causes RhoA downregulation through abnormal truncation of C/EBPß.

Microtubule acetylation has been shown to regulate actin filament dynamics by modulating signaling pathways that control actin organization, although the precise mechanisms remain unknown. In this study, we found that the downregulation of microtubule acetylation via the disruption ATAT1 (which encodes α-tubulin N-acetyltransferase 1) inhibited the expression of RhoA, a small GTPase involved in regulating the organization of actin filaments and the formation of stress fibers. Analysis of RHOA promoter and chromatin immunoprecipitation assays revealed that C/EBPß is a major regulator of RHOA expression. Interestingly, the majority of C/EBPß in ATAT1 knockout (KO) cells was found in the nucleus as a 27-kDa fragment (referred to as C/EBPßp27) lacking the N-terminus of C/EBPß. Overexpression of a gene encoding a C/EBPßp27-mimicking protein via an N-terminal deletion in C/EBPß led to competitive binding with wild-type C/EBPß at the C/EBPß binding site in the RHOA promoter, resulting in a significant decrease of RHOA expression. We also found that cathepsin L (CTSL), which is overexpressed in ATAT1 KO cells, is responsible for C/EBPßp27 formation in the nucleus. Treatment with a CTSL inhibitor led to the restoration of RHOA expression by downregulation of C/EBPßp27 and the invasive ability of ATAT1 KO MDA-MB-231 breast cancer cells. Collectively, our findings suggest that the downregulation of microtubule acetylation associated with ATAT1 deficiency suppresses RHOA expression by forming C/EBPßp27 in the nucleus through CTSL. We propose that CTSL and C/EBPßp27 may represent a novel therapeutic target for breast cancer treatment. [BMB Reports 2024; 57(6): 293-298].

A CEBPB/miR-32-5p/GATA6 axis promotes vascular calcification in type 2 diabetes.

Vascular calcification in diabetes patients is a major independent risk factor for developing diabetic cardiovascular complications. However, the mechanisms by which diabetes leads to vascular calcification are complex and not yet fully understood. Our previous study revealed that miR-32-5p is a potential new diagnostic marker for coronary artery calcification. In this study, we found that miR-32-5p levels were significantly greater in the plasma of type 2 diabetes patients with coronary artery calcification and were positively correlated with the coronary artery calcification score. In type 2 diabetic mice, miR-32-5p levels were also elevated in the aorta, and knockout of miR-32-5p inhibited the osteogenic differentiation of vascular smooth muscle cells in vivo. Furthermore, overexpression of miR-32-5p promoted vascular smooth muscle cell calcification, while antagonism of miR-32-5p inhibited vascular smooth muscle cell calcification under high-glucose conditions. GATA binding protein 6 (GATA6) was identified as the key target gene through which miR-32-5p promotes vascular smooth muscle cell calcification. Overexpression of GATA6 antagonized the effects of miR-32-5p on vascular calcification. Additionally, high glucose levels were shown to induce the upregulation of miR-32-5p by activating CCAAT/enhancer binding protein beta (CEBPB). These results suggest that miR-32-5p is an important procalcification factor in vascular calcification associated with type 2 diabetes and identify the CEBPB/miR-32-5p/GATA6 axis as a potential biomarker and therapeutic target for preventing and treating vascular calcification in type 2 diabetes.

Nonstructural protein 14 of PDCoV promotes complement C3 expression via the activation of p38-MAPK-C/EBP pathway.

Porcine deltacoronavirus (PDCoV) is an emergent enteric coronavirus, primarily inducing diarrhea in swine, particularly in nursing piglets, with the additional potential for zoonotic transmission to humans. Despite the significant impact of PDCoV on swine populations, its pathogenic mechanisms remain incompletely understood. Complement component 3 (C3) plays a pivotal role in the prevention of viral infections, however, there are no reports concerning the influence of C3 on the proliferation of PDCoV. In this study, we initially demonstrated that PDCoV is capable of activating the C3 and eliciting inflammatory responses. The overexpression of C3 significantly suppressed PDCoV replication, while inhibition of C3 expression facilitated PDCoV replication. We discovered that nonstructural proteins Nsp7, Nsp14, and M, considerably stimulated C3 expression, particularly Nsp14, through activation of the p38-MAPK-C/EBP-ß pathway. The N7-MTase constitutes a significant functional domain of the non-structural protein Nsp14, which is more obvious to upregulate C3. Furthermore, functional mutants of the N7-MTase domain suggested that the D44 and T135 of N7-Mtase constituted a pivotal amino acid site to promote C3 expression. This provides fresh insights into comprehending how the virus manipulates the host immune response and suggests potential antiviral strategies against PDCoV.

RPLP1 restricts HIV-1 transcription by disrupting C/EBPß binding to the LTR.

Long-term non-progressors (LTNPs) of HIV-1 infection may provide important insights into mechanisms involved in viral control and pathogenesis. Here, our results suggest that the ribosomal protein lateral stalk subunit P1 (RPLP1) is expressed at higher levels in LTNPs compared to regular progressors (RPs). Functionally, RPLP1 inhibits transcription of clade B HIV-1 strains by occupying the C/EBPß binding sites in the viral long terminal repeat (LTR). This interaction requires the α-helixes 2 and 4 domains of RPLP1 and is evaded by HIV-1 group M subtype C and group N, O and P strains that do not require C/EBPß for transcription. We further demonstrate that HIV-1-induced translocation of RPLP1 from the cytoplasm to the nucleus is essential for antiviral activity. Finally, knock-down of RPLP1 promotes reactivation of latent HIV-1 proviruses. Thus, RPLP1 may play a role in the maintenance of HIV-1 latency and resistance to RPLP1 restriction may contribute to the effective spread of clade C HIV-1 strains.

Midkine promotes renal fibrosis by stabilizing C/EBPß to facilitate endothelial-mesenchymal transition.

Numerous myofibroblasts are arisen from endothelial cells (ECs) through endothelial to mesenchymal transition (EndMT) triggered by TGF-ß. However, the mechanism of ECs transforms to a different subtype, or whether there exists an intermediate state of ECs remains unclear. In present study, we demonstrate Midkine (MDK) mainly expressed by CD31 + ACTA2+ECs going through partial EndMT contribute greatly to myofibroblasts by spatial and single-cell transcriptomics. MDK is induced in TGF-ß treated ECs, which upregulates C/EBPß and increases EndMT genes, and these effects could be reversed by siMDK. Mechanistically, MDK promotes the binding ability of C/EBPß with ACTA2 promoter by stabilizing the C/EBPß protein. In vivo, knockout of Mdk or conditional knockout of Mdk in ECs reduces EndMT markers and significantly reverses fibrogenesis. In conclusion, our study provides a mechanistic link between the induction of EndMT by TGF-ß and MDK, which suggests that blocking MDK provides potential therapeutic strategies for renal fibrosis.

MiR-320 inhibits PRRSV replication by targeting PRRSV ORF6 and porcine CEBPB.

Porcine reproductive and respiratory syndrome (PRRS), a highly contagious disease caused by Porcine reproductive and respiratory syndrome virus (PRRSV), results in huge economic losses to the world pig industry. MiRNAs have been reported to be involved in regulation of viral infection. In our study, miR-320 was one of 21 common differentially expressed miRNAs of Meishan, Pietrain, and Landrace pig breeds at 9-h post-infection (hpi). Bioinformatics and experiments found that PRRSV replication was inhibited by miR-320 through directly targeting PRRSV ORF6. In addition, the expression of CCAAT enhancer binding protein beta (CEBPB) was also inhibited by miR-320 by targeting the 3' UTR of CEBPB, which significantly promotes PRRSV replication. Intramuscular injection of pEGFP-N1-miR-320 verified that miR-320 significantly inhibited the replication of PRRSV and alleviated the symptoms caused by PRRSV in piglets. Taken together, miR-320 have significant roles in the infection and may be promising therapeutic target for PRRS.

Dysregulation of TNF-induced protein 3 and CCAAT/enhancer-binding protein ß in alveolar macrophages: Implications for systemic sclerosis-associated interstitial lung disease.

OBJECTIVES: This study investigates the role of TNF-induced protein 3 (TNFAIP3) and CCAAT/enhancer-binding protein ß (C/EBPß) in alveolar macrophages (AMs) of patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD) and their influence on pulmonary fibrosis. METHODS: Transfection of HEK293T cells and AMs with plasmids carrying TNFAIP3 and C/EBPß was performed, followed by co-culturing AMs with pulmonary fibroblasts. Immunoblotting analysis was then utilized to assess the expression of TNFAIP3, C/EBPß, and collagen type 1 (Col1). Quantitative PCR analysis was conducted to quantify the mRNA levels of C/EBPß, IL-10, and TGF-ß1. STRING database analysis, and immunoprecipitation assays were employed to investigate the interactions between TNFAIP3 and C/EBPß. RESULTS: TNFAIP3 expression was significantly reduced in SSc-ILD AMs, correlating with increased Col1 production in fibroblasts. Overexpression of TNFAIP3 inhibited this pro-fibrotic activity. Conversely, C/EBPß expression was elevated in SSc-ILD AMs, and its reduction through TNFAIP3 restoration decreased pro-fibrotic cytokines IL-10 and TGFß1 levels. Protein-protein interaction studies confirmed the regulatory relationship between TNFAIP3 and C/EBPß. CONCLUSIONS: This study highlights the important role of TNFAIP3 in regulating pulmonary fibrosis in SSc-ILD by modulating C/EBPß expression in AMs. These findings suggest that targeting TNFAIP3 could be a potential therapeutic strategy for managing SSc-ILD patients.

cGAS suppresses ß-cell proliferation by a STING-independent but CEBPß-dependent mechanism.

AIMS/HYPOTHESIS: cGAS (cyclic GMP-AMP synthase) has been implicated in various cellular processes, but its role in ß-cell proliferation and diabetes is not fully understood. This study investigates the impact of cGAS on ß-cell proliferation, particularly in the context of diabetes. METHODS: Utilizing mouse models, including cGAS and STING (stimulator of interferon genes) knockout mice, we explored the role of cGAS in ß-cell function. This involved ß-cell-specific cGAS knockout (cGASßKO) mice, created by breeding cGAS floxed mice with transgenic mice expressing Cre recombinase under the insulin II promoter. We analyzed cGAS expression in diabetic mouse models, evaluated the effects of cGAS deficiency on glucose tolerance, and investigated the molecular mechanisms underlying these effects through RNA sequencing. RESULTS: cGAS expression is upregulated in the islets of diabetic mice and by high glucose treatment in MIN6 cells. Both global cGAS deficiency and ß-cell-specific cGAS knockout mice lead to improved glucose tolerance by promoting ß-cell mass. Interestingly, STING knockout did not affect pancreatic ß-cell mass, suggesting a STING-independent mechanism for cGAS's role in ß-cells. Further analyses revealed that cGAS- but not STING-deficiency leads to reduced expression of CEBPß, a known suppressor of ß-cell proliferation, concurrently with increased ß-cell proliferation. Moreover, overexpression of CEBPß reverses the upregulation of Cyclin D1 and D2 induced by cGAS deficiency, thereby regulating ß-cell proliferation. These results confirm that cGAS regulation of ß-cell proliferation via a CEBPß-dependent but STING-independent mechanism. CONCLUSIONS/INTERPRETATION: Our findings highlight the pivotal role of cGAS in promoting ß-cell proliferation and maintaining glucose homeostasis, potentially by regulating CEBPß expression in a STING-independent manner. This study uncovers the significance of cGAS in controlling ß-cell mass and identifies a potential therapeutic target for enhancing ß-cell proliferation in the treatment of diabetes.

Gallic Acid Attenuates Sepsis-Induced Liver Injury through C/EBPß-Dependent MAPK Signaling Pathway.

SCOPE: Liver injury is a major complication associated with sepsis. Together with others, the study has shown that gallic acid (GA) exerts anti-inflammatory and antioxidant effects in vivo. However, the role of GA in sepsis-mediated hepatic impairment and the underlying mechanisms remains to be elucidated. METHODS AND RESULTS: C57BL/6J mice are pretreated with saline or GA and subjected to sham or cecal ligation and puncture (CLP). The pathological alterations are assessed by hematoxylin and eosin staining as well as immunohistochemical staining. RNA sequencing is employed to analyze hepatic transcriptome modifications. The study finds that GA supplementation significantly ameliorates CLP-induced mortality, liver dysfunction, and inflammation. RNA sequencing reveals that 1324 genes are markedly differentially regulated in livers of saline- or GA-treated sham or CLP mice. Gene ontology analysis demonstrates that the differentially expressed genes regulated by GA are predominantly correlated with the immune system process, oxidation-reduction process, and inflammatory response. Furthermore, mitogen-activated protein kinase (MAPK) signaling is localized in the center of the GA-mediated pathway network. Notably, activation of MAPK by C16-PAF significantly blocks GA-mediated protective effects on hepatic injury, inflammation, as well as CCAAT/enhancer-binding protein-ß (C/EBPß) dependent extracellular signal-regulated kinase 1/2 (ERK1/2) and nuclear factor-κB (NF-κB) signaling. CONCLUSION: Therefore, this study indicates that GA may offer a promising therapeutic opportunity for sepsis-associated liver injury.

C/EBPß: A transcription factor associated with the irreversible progression of Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disorder distinguished by a swift cognitive deterioration accompanied by distinctive pathological hallmarks such as extracellular Aß (ß-amyloid) peptides, neuronal neurofibrillary tangles (NFTs), sustained neuroinflammation, and synaptic degeneration. The elevated frequency of AD cases and its proclivity to manifest at a younger age present a pressing challenge in the quest for novel therapeutic interventions. Numerous investigations have substantiated the involvement of C/EBPß in the progression of AD pathology, thus indicating its potential as a therapeutic target for AD treatment. AIMS: Several studies have demonstrated an elevation in the expression level of C/EBPß among individuals afflicted with AD. Consequently, this review predominantly delves into the association between C/EBPß expression and the pathological progression of Alzheimer's disease, elucidating its underlying molecular mechanism, and pointing out the possibility that C/EBPß can be a new therapeutic target for AD. METHODS: A systematic literature search was performed across multiple databases, including PubMed, Google Scholar, and so on, utilizing predetermined keywords and MeSH terms, without temporal constraints. The inclusion criteria encompassed diverse study designs, such as experimental, case-control, and cohort studies, restricted to publications in the English language, while conference abstracts and unpublished sources were excluded. RESULTS: Overexpression of C/EBPß exacerbates the pathological features of AD, primarily by promoting neuroinflammation and mediating the transcriptional regulation of key molecular pathways, including δ-secretase, apolipoprotein E4 (APOE4), acidic leucine-rich nuclear phosphoprotein-32A (ANP32A), transient receptor potential channel 1 (TRPC1), and Forkhead BoxO (FOXO). DISCUSSION: The correlation between overexpression of C/EBPß and the pathological development of AD, along with its molecular mechanisms, is evident. Investigating the pathways through which C/EBPß regulates the development of AD reveals numerous multiple vicious cycle pathways exacerbating the pathological progression of the disease. Furthermore, the exacerbation of pathological progression due to C/EBPß overexpression and its molecular mechanism is not limited to AD but also extends to other neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and multiple sclerosis (MS). CONCLUSION: The overexpression of C/EBPß accelerates the irreversible progression of AD pathophysiology. Additionally, C/EBPß plays a crucial role in mediating multiple pathways linked to AD pathology, some of which engender vicious cycles, leading to the establishment of feedback mechanisms. To sum up, targeting C/EBPß could hold promise as a therapeutic strategy not only for AD but also for other degenerative diseases.

Hydrangea paniculata coumarins alleviate adriamycin-induced renal lipotoxicity through activating AMPK and inhibiting C/EBPß.

ETHNOPHARMACOLOGICAL RELEVANCE: Throughout Chinese history, Hydrangea paniculata Siebold has been utilized as a traditional medicinal herb to treat a variety of ailments associated to inflammation. In a number of immune-mediated kidney disorders, total coumarins extracted from Hydrangea paniculata (HP) have demonstrated a renal protective effect. AIM OF THE STUDY: To investigate renal beneficial effect of HP on experimental Adriamycin nephropathy (AN), and further clarify whether reversing lipid metabolism abnormalities by HP contributes to its renoprotective effect and find out the underlying critical pathways. MATERIALS AND METHODS: After establishment of rat AN model, HP was orally administrated for 6 weeks. Biochemical indicators related to kidney injury were determined. mRNAs sequencing using kidney tissues were performed to clarify the underlying mechanism. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis, western blot, molecular docking, and drug affinity responsive target stability (DARTS) assay was carried out to further explore and confirm pivotal molecular pathways and possible target by which HP and 7-hydroxylcoumarin (7-HC) played their renal protection effect via modulating lipid metabolism. RESULTS: HP could significantly improve renal function, and restore renal tubular abnormal lipid metabolism and interstitial fibrosis in AN. In vitro study demonstrated that HP and its main metabolite 7-HC could reduce ADR-induced intracellular lipid deposition and fibrosis characteristics in renal tubular cells. Mechanically, HP and 7-HC can activate AMP-activated protein kinase (AMPK) via direct interaction, which contributes to its lipid metabolism modulation effect. Moreover, HP and 7-HC can inhibit fibrosis by inhibiting CCAAT/enhancer binding protein beta (C/EBPß) expression in renal tubular cells. Normalization of lipid metabolism by HP and 7-HC further provided protection of mitochondrial structure integrity and inhibited the nuclear factor kappa-B (NF-κB) pathway. Long-term toxicity using beagle dogs proved the safety of HP after one-month administration. CONCLUSION: Coumarin derivates from HP alleviate adriamycin-induced lipotoxicity and fibrosis in kidney through activating AMPK and inhibiting C/EBPß.

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)-1ß, 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.

The Involvement of the microRNAs miR-466c and miR-340 in the Palmitate-Mediated Dysregulation of Gonadotropin-Releasing Hormone Gene Expression.

Diets high in saturated fatty acids are associated with obesity and infertility. Palmitate, the most prevalent circulating saturated fatty acid, is sensed by hypothalamic neurons, contributing to homeostatic dysregulation. Notably, palmitate elevates the mRNA levels of gonadotropin-releasing hormone (Gnrh) mRNA and its activating transcription factor, GATA binding protein 4 (Gata4). GATA4 is essential for basal Gnrh expression by binding to its enhancer region, with Oct-1 (Oct1) and CEBP-ß (Cebpb) playing regulatory roles. The pre- and post-transcriptional control of Gnrh by palmitate have not been investigated. Given the ability of palmitate to alter microRNAs (miRNAs), we hypothesized that palmitate-mediated dysregulation of Gnrh mRNA involves specific miRNAs. In the mHypoA-GnRH/GFP neurons, palmitate significantly downregulated six miRNAs (miR-125a, miR-181b, miR-340, miR-351, miR-466c and miR-503), and the repression was attenuated by co-treatment with 100 µM of oleate. Subsequent mimic transfections revealed that miR-466c significantly downregulates Gnrh, Gata4, and Chop mRNA and increases Per2, whereas miR-340 upregulates Gnrh, Gata4, Oct1, Cebpb, and Per2 mRNA. Our findings suggest that palmitate may indirectly regulate Gnrh at both the pre- and post-transcriptional levels by altering miR-466c and miR-340, which in turn regulate transcription factor expression levels. In summary, palmitate-mediated dysregulation of Gnrh and, consequently, reproductive function involves parallel transcriptional mechanisms.

TG-interacting factor 1 regulates mitotic clonal expansion during adipocyte differentiation.

Obesity is one of the significant health challenges in the world and is highly associated with abnormal adipogenesis. TG-interacting factor 1 (TGIF1) is essential for differentiating murine adipocytes and human adipose tissue-derived stem cells. However, the mode of action needs to be better elucidated. To investigate the roles of TGIF1 in differentiation in-depth, CRISPR/Cas9 knockout technology was performed to generate TGIF1-silenced preadipocytes. The absence of TGIF1 in 3 T3-F442A preadipocytes abolished lipid accumulation throughout the differentiation using Oil Red O staining. Conversely, we established 3 T3-F442A preadipocytes stably expressing TGIF1 and doxycycline-inducible TGIF1 in TGIF1-silenced 3 T3-F442A preadipocytes. Remarkably, the induction of TGIF1 by doxycycline during the initial differentiation phase successfully promoted lipid accumulation in TGIF1-silenced 3 T3-F442A cells. We further explored the mechanisms of TGIF1 in early differentiation. We demonstrated that TGIF1 promoted the mitotic clonal expansion via upregulation of CCAAT/enhancer-binding proteins ß expression, interruption with peroxisome proliferators activated receptor γ downstream regulation, and inhibition of p27kip1 expression. In conclusion, we strengthen the pivotal roles of TGIF1 in early differentiation, which might contribute to resolving obesity-associated metabolic syndromes.

rs822336 binding to C/EBPß and NFIC modulates induction of PD-L1 expression and predicts anti-PD-1/PD-L1 therapy in advanced NSCLC.

Efficient predictive biomarkers are needed for immune checkpoint inhibitor (ICI)-based immunotherapy in non-small cell lung cancer (NSCLC). Testing the predictive value of single nucleotide polymorphisms (SNPs) in programmed cell death 1 (PD-1) or its ligand 1 (PD-L1) has shown contrasting results. Here, we aim to validate the predictive value of PD-L1 SNPs in advanced NSCLC patients treated with ICIs as well as to define the molecular mechanisms underlying the role of the identified SNP candidate. rs822336 efficiently predicted response to anti-PD-1/PD-L1 immunotherapy in advanced non-oncogene addicted NSCLC patients as compared to rs2282055 and rs4143815. rs822336 mapped to the promoter/enhancer region of PD-L1, differentially affecting the induction of PD-L1 expression in human NSCLC cell lines as well as their susceptibility to HLA class I antigen matched PBMCs incubated with anti-PD-1 monoclonal antibody nivolumab. The induction of PD-L1 expression by rs822336 was mediated by a competitive allele-specificity binding of two identified transcription factors: C/EBPß and NFIC. As a result, silencing of C/EBPß and NFIC differentially regulated the induction of PD-L1 expression in human NSCLC cell lines carrying different rs822336 genotypes. Analysis by binding microarray further validated the competitive allele-specificity binding of C/EBPß and NFIC to PD-L1 promoter/enhancer region based on rs822336 genotype in human NSCLC cell lines. These findings have high clinical relevance since identify rs822336 and induction of PD-L1 expression as novel biomarkers for predicting anti-PD-1/PD-L1-based immunotherapy in advanced NSCLC patients.

TMF inhibits extracellular matrix degradation by regulating the C/EBPß/ADAMTS5 signaling pathway in osteoarthritis.

Osteoarthritis (OA) is a chronic joint disease, characterized by degenerative destruction of articular cartilage. Chondrocytes, the unique cell type in cartilage, mediate the metabolism of extracellular matrix (ECM), which is mainly constituted by aggrecan and type II collagen. A disintegrin and metalloproteinase with thrombospondin 5 (ADAMTS5) is an aggrecanase responsible for the degradation of aggrecan in OA cartilage. CCAAT/enhancer binding protein ß (C/EBPß), a transcription factor in the C/EBP family, has been reported to mediate the expression of ADAMTS5. Our previous study showed that 5,7,3',4'-tetramethoxyflavone (TMF) could activate the Sirt1/FOXO3a signaling in OA chondrocytes. However, whether TMF protected against ECM degradation by down-regulating C/EBPß expression was unknown. In this study, we found that aggrecan expression was down-regulated, and ADAMTS5 expression was up-regulated. Knockdown of C/EBPß could up-regulate aggrecan expression and down-regulate ADAMTS5 expression in IL-1ß-treated C28/I2 cells. TMF could compromise the effects of C/EBPß on OA chondrocytes by activating the Sirt1/FOXO3a signaling. Conclusively, TMF exhibited protective activity against ECM degradation by mediating the Sirt1/FOXO3a/C/EBPß pathway in OA chondrocytes.

Engineered human osteoarthritic cartilage organoids.

The availability of human cell-based models capturing molecular processes of cartilage degeneration can facilitate development of disease-modifying therapies for osteoarthritis [1], a currently unmet clinical need. Here, by imposing specific inflammatory challenges upon mesenchymal stromal cells at a defined stage of chondrogenesis, we engineered a human organotypic model which recapitulates main OA pathological traits such as chondrocyte hypertrophy, cartilage matrix mineralization, enhanced catabolism and mechanical stiffening. To exemplify the utility of the model, we exposed the engineered OA cartilage organoids to factors known to attenuate pathological features, including IL-1Ra, and carried out mass spectrometry-based proteomics. We identified that IL-1Ra strongly reduced production of the transcription factor CCAAT/enhancer-binding protein beta [2] and demonstrated that inhibition of the C/EBPß-activating kinases could revert the degradative processes. Human OA cartilage organoids thus represent a relevant tool towards the discovery of new molecular drivers of cartilage degeneration and the assessment of therapeutics targeting associated pathways.