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AIMS: Pulmonary hypertension (PH) is a pulmonary vascular disease characterized by a high mortality rate. Pulmonary arterial endothelium cells (PAECs) serve as a primary sensor of various environmental cues, such as shear stress and hypoxia, but PAEC dysfunction may trigger vascular remodelling during the onset of PH. This study aimed to illustrate the role of Sirtuin 7 (SIRT7) in endothelial dysfunction during PH and explore the potential therapeutic strategy for PH. METHODS AND RESULTS: SIRT7 levels were measured in human and murine experimental PH samples. Bioinformatic analysis, immunoprecipitation, and deacetylation assay were used to identify the association between SIRT7 and Krüpple-like factor 4 (KLF4), a key transcription factor essential for endothelial cell (EC) homeostasis. Sugen5416 + hypoxia (SuHx)-induced PH mouse models and cell cultures were used for the study of the therapeutic effect of SIRT7 for PH. SIRT7 level was significantly reduced in lung tissues and PAECs from PH patients and the SuHx-induced PH mouse model as compared with healthy controls. Pulmonary endothelium-specific depletion of Sirt7 increased right ventricular systolic pressure and exacerbated right ventricular hypertrophy in the SuHx-induced PH model. At the molecular level, we identified KLF4 as a downstream target of SIRT7, which deacetylated KLF4 at K228 and inhibited the ubiquitination-proteasome degradation. Thus, the SIRT7/KLF4 axis maintained PAEC homeostasis by regulating proliferation, migration, and tube formation. PAEC dysfunction was reversed by adeno-associated virus type 1 vector-mediated endothelial overexpression of Sirt7 or supplementation with nicotinamide adenine dinucleotide (NAD)+ intermediate nicotinamide riboside which activated Sirt7; both approaches successfully reversed PH phenotypes. CONCLUSION: The SIRT7/KLF4 axis ensures PAEC homeostasis, and pulmonary endothelium-specific SIRT7 targeting might constitute a PH therapeutic strategy.

Cardiovascular diseases (CVDs) are a leading cause of mortality worldwide and are associated with an overactivated sympathetic system. Although exercise training has shown promise in mitigating sympathetic stress-induced cardiac remodeling, the precise mechanisms remain elusive. Here, we demonstrate that exercise significantly upregulates cardiac flavin-containing monooxygenase 2 (FMO2) expression. Notably, we find that exercise training effectively counteracts sympathetic overactivation-induced cardiac dysfunction and fibrosis by enhancing FMO2 expression via adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK) activation. Functional investigations employing FMO2 knockdown with adeno-associated virus 9 (AAV9) underscore the necessity for FMO2 expression to protect the heart during exercise in vivo. Furthermore, we identify the krüppel-like factor 4 (KLF4) as a transcriptional mediator of FMO2 that is crucial for the mechanism through which AMPK activation protects against sympathetic overactivation-induced cardiac dysfunction and fibrosis. Taken together, our study reveals a cardioprotective mechanism for exercise training through an AMPK-KLF4-FMO2 signaling pathway that underscores how exercise alleviates cardiac dysfunction induced by excessive sympathetic activation. [Display omitted] • Exercise training increases cardiac expression of FMO2. • Exercise training mitigates ISO-induced cardiac dysfunction by increasing FMO2. • Exercise training induces FMO2 expression by AMPK activation. • KLF4 is the transcription factor of FMO2. [ABSTRACT FROM AUTHOR]

Granulosa cell (GC) death, which leads to follicular atresia, primarily occurs through apoptosis and autophagy. miRNAs are known to be key regulators of autophagy and apoptosis. Although miR-7 acting as a key regulator of follicular atresia, its precise role in granulosa cell autophagy and apoptosis remains to be fully elucidated. In this study, we found that miR-7 was highly expressed in the follicle based on qPCR analysis. Subsequently, transfection of miR-7 inhibitors and mimics downregulated or upregulated the expression of miR-7 and promoted autophagic and apoptotic processes in chicken follicle granulosa cells. Mechanistically, through dual-luciferase reporter gene assays, we validated that KLF4 is a target gene of miR-7. Contrarily, KLF4 was found to negatively regulate autophagy and apoptosis in follicular granulosa cells as evidenced by genetic intervention of KLF4 silencing and overexpression. Furthermore, JAK/STAT3 signaling pathway was confirmed to mediate the regulation of miR-7-KLF4 axis on GC autophagy and apoptosis. These findings offer evidences of the crucial involvement of the miR-7-KLF4 signaling axis in determining autophagy and apoptosis of GCs. This study could offer an important theoretical basis for the use of molecular-assisted breeding in chickens. • KLF4 mediates the promotion of miR-7 on autophagy and apoptosis in chicken follicular granulosa cells. • The miR-7-KLF4 axis is operated through JAK/STAT3 signaling pathway. • The miR-7-KLF4 axis promotes autophagy and apoptosis in chicken granulosa cells through JAK/STAT3 pathway. [ABSTRACT FROM AUTHOR]

Ovarian cancer (OC) is a highly fatal gynecological malignancy worldwide, and cisplatin (CDDP) is commonly used as an initial chemotherapy treatment for OC. Nonetheless, most patients ultimately face recurrence because of resistance to cisplatin. Therefore, it is imperative to investigate the underlying mechanisms of drug resistance in OC. By analyzing differential gene expression using TCGA, GDSC, and GEO public databases, we discovered that increased KLF4 expression is strongly linked to chemotherapy resistance and unfavorable outcomes in OC. Subsequent validation through immunohistochemistry and western blotting confirmed the upregulated KLF4 expression in cisplatin-resistance OC cells lines and tissues. To investigate the function of KLF4, functional experiments were performed both in vitro and in vivo. We observed that knocking down KLF4 impaired cisplatin-resistance of OC. Further mechanism research based on RNA-seq and gene enrichment analysis revealed that interfering KLF4 suppressed the activation of mTORC1 pathway. Finally, rescue experiment demonstrated that using mTORC1 pathway inhibitor could attenuate the cisplatin resistance induced by the overexpression of KLF4. In conclusion, our research indicates that KLF4 promotes cisplatin resistance through the activation of mTORC1 signaling, and proposes that inhibiting KLF4 might serve as a viable therapeutic approach to overcoming drug resistance in ovarian cancer. [ABSTRACT FROM AUTHOR]

Sialylation catalysed by sialyltransferase 7A (SIAT7A) plays a role in the development of cardiac hypertrophy. However, the regulatory mechanisms upstream of SIAT7A in this context remain poorly elucidated. Previous study demonstrated that KLF4 activates the SIAT7A gene in ischemic myocardium by binding to its promoter region. Nevertheless, the potential involvement of KLF4 in regulating SIAT7A expression in Ang II‐induced hypertrophic cardiomyocytes remains uncertain. This study seeks to deepen the underlying mechanisms of the KLF4 and SIAT7A interaction in the progression of Ang II‐induced cardiac hypertrophy. The results showed a concurrent increase in SIAT7A and KLF4 levels in hypertrophic myocardium of essential hypertension patients and in hypertrophic cardiomyocytes stimulated by Ang II. In vitro experiments revealed that reducing KLF4 levels led to a decrease in both SIAT7A synthesis and Sialyl‐Tn antigen expression, consequently inhibiting Ang II‐induced cardiomyocyte hypertrophy. Intriguingly, reducing SIAT7A levels also resulted in decreased KLF4 expression and suppression cardiomyocyte hypertrophy. Consistent with this, elevating SIAT7A levels increased KLF4 expression and exacerbated cardiomyocyte hypertrophy in both in vivo and in vitro experiments. Additionally, a time‐course analysis indicated that KLF4 expression preceded that of SIAT7A. Luciferase reporter assays further confirmed that modulating SIAT7A levels directly influenced the transcriptional activity of KLF4 in cardiomyocytes. In summary, KLF4 expression is upregulated in cardiomyocytes treated with Ang II, which subsequently induces the expression of SIAT7A. The elevated levels of SIAT7A, in turn, enhance the transcription of KLF4. These findings suggest a positive feedback loop between KLF4 and SIAT7A‐Sialyl‐Tn, ultimately promoting Ang II‐induced cardiac hypertrophy. [ABSTRACT FROM AUTHOR]

Cholangiocarcinoma is one of the most lethal human cancers, and chemotherapy failure is a major cause of recurrence and poor prognosis. We previously demonstrated that miR-200 family members are downregulated in clinical samples of cholangiocarcinoma and inhibit cholangiocarcinoma tumorigenesis and metastasis. However, the role of differentially expressed miR-200b-3p in 5-fluorouracil chemosensitivity remains unclear. Here, we examined how miR-200b-3p modulates 5-fluorouracil chemosensitivity in cholangiocarcinoma. We observed that miR-200b-3p was associated with 5-fluorouracil sensitivity in cholangiocarcinoma and increased 5-fluorouracil-induced mitochondrial apoptosis in cholangiocarcinoma cells. Mechanistically, miR-200b-3p suppressed autophagy in cholangiocarcinoma cells to mediate 5-fluorouracil sensitivity. Further, we identified KLF4 as an essential target of miR-200b-3p in cholangiocarcinoma. Notably, the miR-200b-3p/KLF4/autophagy pathway augmented the chemosensitivity of cholangiocarcinoma cells to 5-fluorouracil. Our findings underscore the key role of miR-200b-3p in chemosensitivity to 5-fluorouracil and highlight the miR-200b-3p/KLF4/autophagy axis as a potential therapeutic target for cholangiocarcinoma.

Abstract Ovarian cancer (OC) is a highly fatal gynecological malignancy worldwide, and cisplatin (CDDP) is commonly used as an initial chemotherapy treatment for OC. Nonetheless, most patients ultimately face recurrence because of resistance to cisplatin. Therefore, it is imperative to investigate the underlying mechanisms of drug resistance in OC. By analyzing differential gene expression using TCGA, GDSC, and GEO public databases, we discovered that increased KLF4 expression is strongly linked to chemotherapy resistance and unfavorable outcomes in OC. Subsequent validation through immunohistochemistry and western blotting confirmed the upregulated KLF4 expression in cisplatin-resistance OC cells lines and tissues. To investigate the function of KLF4, functional experiments were performed both in vitro and in vivo. We observed that knocking down KLF4 impaired cisplatin-resistance of OC. Further mechanism research based on RNA-seq and gene enrichment analysis revealed that interfering KLF4 suppressed the activation of mTORC1 pathway. Finally, rescue experiment demonstrated that using mTORC1 pathway inhibitor could attenuate the cisplatin resistance induced by the overexpression of KLF4. In conclusion, our research indicates that KLF4 promotes cisplatin resistance through the activation of mTORC1 signaling, and proposes that inhibiting KLF4 might serve as a viable therapeutic approach to overcoming drug resistance in ovarian cancer.

Abstract Background Recurrent spontaneous abortion (RSA) is defined as two or more consecutive spontaneous abortions before 20 weeks with the same spouse [1]. However, approximately 50% of RSA cases of unknown cause are classified as unexplained recurrent spontaneous abortion (URSA). Potential factors include decreased trophoblast cell migration and invasion, leading to impaired placental implantation and maintenance of the normal maternal-fetal interface. However, the mechanism of this pathogenesis remains unknown. In this study, we investigated the potential role and mechanism of KLF4 in regulating URSA by influencing the invasion and migration ability of trophoblast cells. Methods We firstly identified 817 differentially expressed genes by performing a difference analysis of the dataset GSE121950 [2] related to recurrent abortion, and intersected the top 10 genes obtained respectively by the three algorithms: DMNC, MNC, and EPC using Venn Diagram.To detect the expression levels of core genes, villi samples were obtained from normal pregnant women and patients with URSA. RT-qPCR analysis revealed a significant difference in KLF4 mRNA expression and KLF4 was then analyzed. Trophoblast cell lines HTR8 and JEG3 were used to investigate the effect of KLF4 on trophoblastic function. Wound healing and transwell assays was performed to detect the invasion and migration of trophoblast cells. The expression of epithelial-mesenchymal transition(EMT) molecules were detected by RT-qPCR and western blot. Promoter detection and epigenetic modification were detected by chromatin immunoprecipitation (ChIP) assay. Molecular nuclear localization was detected by immunofluorescence and subcellular fractionation. Miscarried mice model was used to study the effects of KLF4 on URSA induced by reduced trophoblast invasion and migration. Results KLF4 is highly expressed in the villi of patients with URSA. KLF4 inhibits the expression level of H3R2ME2a in trophoblast cells by regulating the transcriptional level and nuclear translocation of PRMT6, thereby inhibiting the possible regulatory mechanism of trophoblastic invasion and providing a potential treatment strategy for URSA in vivo. Conclusions The KLF4/PRMT6/H3R2ME2a axis regulates mechanisms associated with unexplained recurrent spontaneous abortion by regulating trophoblast function.

Abstract Background Uveal melanoma (UM), the most common adult intraocular tumor, is characterized by high malignancy and poor prognosis in advanced stages. Angiogenesis is critical for UM development, however, not only the role of vascular endothelial dysfunction in UM remains unknown, but also their analysis at the single-cell level has been lacking. A comprehensive analysis is essential to clarify the role of the endothelium in the development of UM. Methods By using single-cell RNA transcriptomics data of 11 cases of primary and liver metastasis UM, we analyzed the endothelial cell status. In addition, we analyzed and validated ECs in the in vitro model and collected clinical specimens. Subsequently, we explored the impact of endothelial dysfunction on UM cell migration and explored the mechanisms responsible for the endothelial cell abnormalities and the reasons for their peripheral effects. Results UM metastasis has a significantly higher percentage of vascular endothelial cells compared to in situ tumors, and endothelial cells in metastasis show significant senescence. Senescent endothelial cells in metastatic tumors showed significant Krüppel-like factor 4 (KLF4) upregulation, overexpression of KLF4 in normal endothelial cells induced senescence, and knockdown of KLF4 in senescent endothelium inhibited senescence, suggesting that KLF4 is a driver gene for endothelial senescence. KLF4-induced endothelial senescence drove tumor cell migration through a senescence-associated secretory phenotype (SASP), of which the most important component of the effector was CXCL12 (C-X-C motif chemokine ligand 12), and participated in the composition of the immunosuppressive microenvironment. Conclusion This study provides an undesirable insight of senescent endothelial cells in promoting UM metastasis.

Embryonic stem cells (ESCs) preserve the unique ability to differentiate into any somatic cell lineage while maintaining their self-renewal potential, relying on a complex interplay of extracellular signals regulating the expression/activity of pluripotency transcription factors and their targets. Leukemia inhibitory factor (LIF)-activated STAT3 drives ESCs' stemness by a number of mechanisms, including the transcriptional induction of pluripotency factors such as Klf4 and the maintenance of a stem-like epigenetic landscape. However, it is unknown if STAT3 directly controls stem-cell specific non-coding RNAs, crucial to balance pluripotency and differentiation. Applying a bioinformatic pipeline, here we identify Lncenc1 in mouse ESCs as an STAT3-dependent long non-coding RNA that supports pluripotency. Lncenc1 acts in the cytoplasm as a positive feedback regulator of the LIF–STAT3 axis by competing for the binding of microRNA-128 to the 3'UTR of the Klf4 core pluripotency factor mRNA, enhancing its expression. Our results unveil a novel non-coding RNA-based mechanism for LIF–STAT3-mediated pluripotency. [ABSTRACT FROM AUTHOR]

Problem: Accelerated placental aging is linked to abnormal fetal growth, preeclampsia (PE), and preterm birth (PTB). NANOG, a transcription factor, is known for its role in cellular reprogramming, self‐renewal, and clonogenic growth. Its expression is regulated by Kruppel‐like factor 4 (KLF4), which functions as both a transcriptional activator and repressor. This study evaluated the KLF4‐NANOG pathway in placental samples from normal pregnancies (NP) as well as those with PE, fetal growth restriction (FGR), and PTB. Method of Study: Placental samples from NP pregnancies and those with PE, FGR, and PTB were analyzed for NANOG and KLF4 expression using western blotting and immunohistochemistry. Results: NANOG protein expression was significantly increased in placentas from PE, FGR, and PTB compared to NP (fold changes vs. NP: PE 2.48 ± 0.3, p = 0.002; FGR 1.64 ± 0.16, p = 0.03; PTB 6.03 ± 3.35, p = 0.01). Similarly, KLF4 protein expression was elevated in PE, FGR, and PTB placentas compared to NP (fold changes vs. NP: PE 5.78 ± 0.73, p = 0.001; FGR 2.61 ± 0.43, p = 0.02; PTB 11.42 ± 2.76, p = 0.0006). Immunohistochemistry revealed strong NANOG staining in the syncytiotrophoblast tissue of PE, FGR, and PTB samples, especially in extravillous trophoblasts, compared to NP placentas. Conclusions: The elevated expression of NANOG and KLF4 in abnormal placental tissues suggests their potential role as markers of enhanced placental aging and dysfunction. These findings underscore the importance of the KLF4‐NANOG pathway in the pathology of PE, FGR, and PTB, providing a basis for future research into therapeutic targets for these conditions. [ABSTRACT FROM AUTHOR]

Kruppel‐like factor 4 (Klf4) is a transcription factor that is involved in neuronal regeneration and the development of glutamatergic systems. However, it is unknown whether Klf4 is involved in acute seizure. To investigate the potential role of Klf4 in pentylenetetrazol (PTZ)‐induced seizure, western blotting, immunofluorescence, behaviour test and electrophysiology were conducted in this study. We found that Klf4 protein and mRNA expression were increased in both the hippocampus (HP) and prefrontal cortex (PFC) after PTZ‐induced seizure in mice. HP‐specific knockout (KO) of Klf4 in mice decreased protein expression of Klf4 and the down‐stream Klf4 target tumour protein 53 (TP53/P53). These molecular changes are accompanied by increased seizure latency, reduced immobility time in the forced swimming test and tail suspension test. Reduced hippocampal protein levels for synaptic proteins, including glutamate receptor 1 (GRIA1/GLUA1) and postsynaptic density protein 95 (DLG4/PSD95), were also observed after Klf4‐KO, while increased mRNA levels of complement proteins were observed for complement component 1q subcomponent A (C1qa), complement component 1q subcomponent B (C1qb), complement component 1q subcomponent C (C1qc), complement component 3 (C3), complement component 4A (C4a) and complement component 4B (C4b). Moreover, c‐Fos expression induced by PTZ was reduced by hippocampal conditional KO of Klf4. Electrophysiology showed that PTZ‐induced action potential frequency was decreased by overexpression of Klf4. In conclusion, these findings suggest that Klf4 plays an important role in regulating PTZ‐induced seizures and therefore constitutes a new molecular target that should be explored for the development of antiepileptic drugs. [ABSTRACT FROM AUTHOR]

Fish retinal ganglion cells (RGCs) can regenerate after optic nerve lesions (ONLs). We previously reported that heat shock factor 1 (HSF1) and Yamanaka factors increased in the zebrafish retina 0.5–24 h after ONLs, and they led to cell survival and the transformation of neuro-stem cells. We also showed that retinoic acid (RA) signaling and transglutaminase 2 (TG2) were activated in the fish retina, performing neurite outgrowth 5–30 days after ONLs. In this study, we found that RA signaling and TG2 increased within 0.5 h in the zebrafish retina after ONLs. We examined their interaction with the TG2-specific morpholino and inhibitor due to the significantly close initiation time of TG2 and HSF1. The inhibition of TG2 led to the complete suppression of HSF1 expression. Furthermore, the results of a ChIP assay with an anti-TG2 antibody evidenced significant anti-TG2 immunoprecipitation of HSF1 genome DNA after ONLs. The inhibition of TG2 also suppressed Yamanaka factors' gene expression. This rapid increase in TG2 expression occurred 30 min after the ONLs, and RA signaling occurred 15 min before this change. The present study demonstrates that TG2 regulates Yamanaka factors via HSF1 signals in the acute phase of fish optic nerve regeneration. [ABSTRACT FROM AUTHOR]

The epigenetic layer of regulation has become increasingly relevant in the research focused on tumor suppressors. KLF4 is a well-described zinc-finger transcription factor, mainly known for its role in the acquisition of cell pluripotency. Here we report and describe the most relevant epigenetic regulation mechanisms that affect KLF4 expression in tumors. CpG island methylation emerges as the most common mechanism in several tumors including lung adenocarcinoma, hepatocellular carcinoma, non-Hodgkin lymphomas, among others. Further layers of regulation represented by histone methylation and acetylation and by non-coding RNAs are described. Overall, KLF4 emerges as a crucial target in the fight against cancer. [ABSTRACT FROM AUTHOR]

Reports of Helicobacter pylori (Hp)‐naïve gastric neoplasm (HpNGN) cases have been rapidly increasing due to the recent increase in the Hp‐naïve population in Japan. Most HpNGNs exhibit the gastric immunophenotype and a low malignant potential regardless of histological type. Especially, foveolar‐type gastric adenoma (FGA) and intestinal‐type gastric dysplasia (IGD) rarely progress to invasive carcinoma. FGA is a foveolar epithelial neoplasm that occurs in the fundic gland (oxyntic gland) mucosa and is classified as the flat type or raspberry type (FGA‐RA). The flat type is a large, whitish flatly elevated lesion while FGA‐RA is a small reddish polyp. Genomically, the flat type is characterized by APC and KRAS gene mutations and FGA‐RA by a common single nucleotide variant in the KLF4 gene. This KLF4 single‐nucleotide variant reportedly induces gastric foveolar epithelial tumorigenesis and activates both cell proliferation and apoptosis, leading to its slow‐growing nature. IGD consists of an intestinalized epithelial dysplasia that develops in the pyloric gland mucosa, characterized as a superficial depressed lesion surrounded by raised mucosa showing a gastritis‐like appearance. Immunohistochemically, it exhibits an intestinal or gastrointestinal phenotype and, frequently, p53 overexpression. Thus, IGD shows unique characteristics in HpNGNs and a potential multistep tumorigenic process. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion Chemoresistance is a common event after chemotherapy, including oral squamous cell carcinoma (OSCC). Accumulated evidence suggests that the cancer stemness significantly contributes to therapy resistance. An unresolved question remains regarding how to effectively overcome OSCC chemoresistance by targeting stemness. This study aims to investigate the antitumor effect of metformin and clarify the potential molecular mechanisms.Cellular models resistant to chemotherapy were established, and their viability and sphere‐forming ability were assessed using CCK‐8 and soft agar formation assays, respectively. RNA‐seq and Western blotting analyses were employed to delve into the molecular pathways. Furthermore, to corroborate the inhibitory effects of metformin and cisplatin at an animal level, a subcutaneous tumor transplantation model was instituted.Metformin as a monotherapy exhibited inhibition of stemness traits via Krüppel‐like factor 4 (KLF4). Metformin and cisplatin can synergically inhibit cell proliferation and induce cell apoptosis. Animal experiments confirmed the inhibitory effect of cisplatin and metformin on tumor in mice.Our study proposes a potential therapeutic approach of combining chemotherapy with metformin to overcome chemoresistance in OSCC. [ABSTRACT FROM AUTHOR]

The objective of this study was to elucidate the protective role of quercetin in atherosclerosis by examining its effect on the phenotypic switch of vascular smooth muscle cells (VSMCs) to macrophage-like cells and the underlying regulatory pathways. Aorta tissues from apolipoprotein E-deficient (ApoE KO) mice fed a high-fat diet (HFD), treated with or without 100 mg/kg/day quercetin, were analyzed for histopathological changes and molecular mechanisms. Quercetin was found to decrease the size of atherosclerotic lesions and mitigate lipid accumulation induced by HFD. Fluorescence co-localization analysis revealed a higher presence of macrophage-like vascular smooth muscle cells (VSMCs) co-localizing with phospho-Janus kinase 2 (p-JAK2), phospho-signal transducer and activator of transcription 3 (p-STAT3), and Krüppel-like factor 4 (KLF4) in regions of foam cell aggregation within aortic plaques. However, this co-localization was reduced following treatment with quercetin. Quercetin treatment effectively inhibited the KLF4-mediated phenotypic switch in oxidized low-density lipoprotein (ox-LDL)-loaded mouse aortic vascular smooth muscle cells (MOVAS), as indicated by decreased expressions of KLF4, LGALS3, CD68, and F4/80, increased expression of alpha smooth muscle actin (α-SMA), reduced intracellular fluorescence Dil-ox-LDL uptake, and decreased lipid accumulation. In contrast, APTO-253, a KLF4 activator, was found to reverse the effects of quercetin. Furthermore, AG490, a JAK2 inhibitor, effectively counteracted the ox-LDL-induced JAK2/STAT3 pathway-dependent switch to a macrophage-like phenotype and lipid accumulation in MOVAS cells. These effects were significantly mitigated by quercetin but exacerbated by coumermycin A1, a JAK2 activator. Our research illustrates that quercetin inhibits the KLF4-mediated phenotypic switch of VSMCs to macrophage-like cells and reduces atherosclerosis by suppressing the JAK2/STAT3 pathway. [ABSTRACT FROM AUTHOR]

Background: Uveal melanoma (UM), the most common adult intraocular tumor, is characterized by high malignancy and poor prognosis in advanced stages. Angiogenesis is critical for UM development, however, not only the role of vascular endothelial dysfunction in UM remains unknown, but also their analysis at the single-cell level has been lacking. A comprehensive analysis is essential to clarify the role of the endothelium in the development of UM. Methods: By using single-cell RNA transcriptomics data of 11 cases of primary and liver metastasis UM, we analyzed the endothelial cell status. In addition, we analyzed and validated ECs in the in vitro model and collected clinical specimens. Subsequently, we explored the impact of endothelial dysfunction on UM cell migration and explored the mechanisms responsible for the endothelial cell abnormalities and the reasons for their peripheral effects. Results: UM metastasis has a significantly higher percentage of vascular endothelial cells compared to in situ tumors, and endothelial cells in metastasis show significant senescence. Senescent endothelial cells in metastatic tumors showed significant Krüppel-like factor 4 (KLF4) upregulation, overexpression of KLF4 in normal endothelial cells induced senescence, and knockdown of KLF4 in senescent endothelium inhibited senescence, suggesting that KLF4 is a driver gene for endothelial senescence. KLF4-induced endothelial senescence drove tumor cell migration through a senescence-associated secretory phenotype (SASP), of which the most important component of the effector was CXCL12 (C-X-C motif chemokine ligand 12), and participated in the composition of the immunosuppressive microenvironment. Conclusion: This study provides an undesirable insight of senescent endothelial cells in promoting UM metastasis. [ABSTRACT FROM AUTHOR]

It has been found that CD226 plays an important role in regulating macrophage function, but its expression and function in macrophages during renal fibrogenesis have not been studied. Our data demonstrated that CD226 expression in macrophages was obviously upregulated in the unilateral ureteral obstruction model, while CD226 deficiency attenuated collagen deposition in renal interstitium along with fewer M1 within renal cortex and renal medulla and a lower level of proinflammatory factors compared to that of control littermates. Further studies demonstrated that Cd226−/− bone marrow–derived macrophages transferring could significantly reduce the tubular injury, collagen deposition, and proinflammatory cytokine secretion compared with that of Cd226+/+ bone marrow–derived macrophages transferring in the unilateral ureteral obstruction model. Mechanistic investigations revealed that CD226 promoted proinflammatory M1 macrophage accumulation in the kidney via suppressing KLF4 expression in macrophages. Therefore, our results uncovered a pathogenic role of CD226 during the development of chronic kidney disease by promoting monocyte infiltration from peripheral blood into the kidney and enhancing macrophage activation toward the inflammatory phenotype by suppressing KLF4 expression. [ABSTRACT FROM AUTHOR]

Background and objectives: Colorectal cancer is one of the most significant and deadliest malignant tumors among various types of cancers. Due to its generally low overall survival rate, the development of new treatment strategies for early detection and diagnosis, as well as the identification of prognostic markers, has become exceedingly crucial. The molecular mechanism of colorectal cancer remains uncertain and to address this, the aim is to identify key genes, determine in which pathways these genes are involved, explore their interactions with regulatory molecules, and investigate their overall relationship with survival and immune cell infiltration. Methods: After selecting the databases related to colorectal cancer from the Gene Expression Omnibus database, differentially expressed genes were identified. Gene ontology and pathway analyses were then conducted for these genes, and interaction networks with proteins were constructed. Core genes were identified, and their relationship with regulatory molecules such as miRNAs and transcription factors was examined. Additionally, immune cell infiltration and survival analyses were performed. Results: As a result of the bioinformatic analyses, 71 differentially expressed genes were identified, which were found to overlap in four distinct microarray datasets. Among these differentially expressed genes, Krüppel-like factor 4 (KLF4), CLCA4, GUCA2B, GUCA2A, LGR5, SLC4A4, ZG16, CA7, CA2, and GCG were determined as hub genes. Among the hub genes, CA2, CLCA4, SLC4A4, and KLF4 genes showed a positive correlation with immune cells in immune cell infiltration analyses. The expression levels of these four genes were also confirmed using data from the Human Protein Atlas database. Additionally, only the KLF4 gene was associated with poor prognosis in overall survival analyses. Conclusion: The obtained results suggest that the KLF4 gene may serve as a potential therapeutic agent. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) can progress to renal fibrosis and chronic kidney disease (CKD), which reduces quality of life and increases the economic burden on patients. However, the molecular mechanisms underlying renal fibrosis following AKI remain unclear. This study tested the hypothesis that the Krüppel-like factor 4 (KLF4)/miR-101/Collagen alpha-1X (COL10A1) axis could inhibit epithelial-mesenchymal transition (EMT) and renal fibrosis after AKI in a mouse model of ischemia-reperfusion (I/R)-induced renal fibrosis and HK-2 cells by gene silencing, overexpression, immunofluorescence, immunohistochemistry, real-time quantitative PCR, Western blotting, dual-luciferase reporter assay, fluorescence in situ hybridization (FISH) and ELISA. Compared with the Sham group, I/R induced renal tubular and glomerular injury and fibrosis, and increased the levels of BUN, serum Scr and neutrophil gelatinase-associated lipocalin (NGAL), Col10a1 and Vimentin expression, but decreased E-cadherin expression in the kidney tissues of mice at 42 days post-I/R. Similarly, hypoxia promoted fibroblastic morphological changes in HK-2 cells and enhanced NGAL, COL10A1, Vimentin, and α-SMA expression, but reduced E-cadherin expression in HK-2 cells. These pathological changes were significantly mitigated in COL10A1-silenced renal tissues and HK-2 cells. KLF4 induces miR-101 transcription. More importantly, hypoxia upregulated Vimentin and COL10A1 expression, but decreased miR-101, KLF4, and E-cadherin expression in HK-2 cells. These hypoxic effects were significantly mitigated or abrogated by KLF4 over-expression in the HK-2 cells. Our data indicate that KLF4 up-regulates miR-101 expression, leading to the downregulation of COL10A1 expression, inhibition of EMT and renal fibrosis during the pathogenic process of I/R-related renal fibrosis.

In Parkinson's disease (PD), exogenous ghrelin protects dopaminergic neurons through its receptor, growth hormone secretagogue receptor (GHSR). However, in contrast to the strikingly low levels of ghrelin, GHSR is highly expressed in the substantia nigra (SN). What role does GHSR play in dopaminergic neurons is unknown. In this study, using GHSR knockout mice (Ghsr−/− mice) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD model, we found that GHSR deletion aggravated dopaminergic neurons degeneration, and the expression and activity of GHSR were significantly reduced in PD. Furthermore, we explored the potential mechanism that GHSR deficiency aggregated PD-related neurodegeneration. We showed that DEPTOR, a subunit of mTORC1, was overexpressed in Ghsr−/− mice, positively regulating autophagy and enhancing autophagy initiation. The expression of lysosomal markers was abnormal, implying lysosomal dysfunction. As a result, the damaged mitochondria could not be effectively eliminated, which ultimately exacerbated the injury of nigral dopaminergic neurons. In particular, we demonstrated that DEPTOR could be transcriptionally regulated by KLF4. Specific knockdown of KLF4 in dopaminergic neurons effectively alleviated neurodegeneration in Ghsr−/− mice. In summary, our results suggested that endogenous GHSR deletion-compromised autophagy by impairing lysosomal function, is a key contributor to PD, which provided ideas for therapeutic approaches involving the manipulation of GHSR.

Abstract Aims Myocardial ischaemia–reperfusion injury (MIRI) contributes to serious myocardial injury and even death. Long non‐coding RNAs (lncRNAs) have been reported to play pivotal roles in the occurrence and development of MIRI. Here, the detailed molecular mechanism of lncRNA SNHG1 in MIRI was explored. Methods and results A cell model of MIRI was established through hypoxia/reoxygenation (H/R) stimulation. Cell viability and pyroptosis were evaluated utilizing MTT, PI staining, and flow cytometry. Interleukin (IL)‐1β and IL‐18 secretion levels were examined by ELISA. The gene and protein expression were detected by RT‐qPCR and western blot, respectively. Dual luciferase reporter gene, RIP and ChIP assays were performed to analyse the molecular interactions. The results showed that lncRNA SNHG1 overexpression alleviated H/R‐induced HL‐1 cell pyroptosis (all P

Ephrin receptor A2 (EphA2), a member of the Ephrin receptor family, is closely related to the progression of oral squamous cell carcinoma (OSCC). Cancer stem cells (CSCs) play essential roles in OSCC development and occurrence. The underlying mechanisms between EphA2 and CSCs, however, are not yet fully understood. Here, we found that EphA2 was overexpressed in OSCC tissues and was associated with poor prognosis. Knockdown of EphA2 dampened the CSC phenotype and the tumour-initiating frequency of OSCC cells. Crucially, the effects of EphA2 on the CSC phenotype relied on KLF4, a key transcription factor for CSCs. Mechanistically, EphA2 activated the ERK signalling pathway, promoting the nuclear translocation of YAP. Subsequently, YAP was bound to TEAD3, leading to the transcription of KLF4. Overall, our findings revealed that EphA2 can enhance the stemness of OSCC cells, and this study identified the EphA2/KLF4 axis as a potential target for treating OSCC. [ABSTRACT FROM AUTHOR]

Aging is intricately linked to immune system dysfunction. Recent studies have highlighted the biological function of microRNA‐7 (miR‐7) as a novel regulator of immune cell function and related diseases. However, the potential role of miR‐7 in aging remains unexplored. Here, we investigated the contribution of miR‐7 to d‐gal‐induced aging in mice, focusing on its regulation of senescent Kupffer cells. Our findings revealed that miR‐7 deficiency significantly ameliorated the aging process, characterized by enhanced CD4+ T‐cell activation. However, the adoptive transfer of miR‐7‐deficient CD4+T cells failed to improve the age‐related phenotype. Further analysis showed that miR‐7 deficiency significantly reduced IL‐1β production in liver tissue, and inhibiting IL‐1β in vivo slowed down the aging process in mice. Notably, IL‐1β is mainly produced by senescent Kupffer cells in the liver tissue of aging mice, and miR‐7 expression was significantly up‐regulated in these cells. Mechanistically, KLF4, a target of miR‐7, was down‐regulated in senescent Kupffer cells in aging mouse model. Furthermore, miR‐7 deficiency also modulated the NF‐κB activation and IL‐1β production in senescent Kupffer cells through KLF4. In conclusion, our findings unveil the role of miR‐7 in d‐gal‐induced aging in mice, highlighting its regulation of KLF4/NF‐κB/IL‐1β pathways in senescent Kupffer cells. This research may enhance our understanding of miRNA‐based aging immune cells and offer new avenues for new intervention strategies in aging process. [ABSTRACT FROM AUTHOR]

Special AT-rich sequence binding protein-2 (SATB2) is a nuclear matrix protein that binds to nuclear attachment regions and is involved in chromatin remodeling and transcription regulation. In stem cells, it regulates the expression of genes required for maintaining pluripotency and self-renewal and epithelial–mesenchymal transition (EMT). In this study, we examined the oncogenic role of SATB2 in prostate cancer and assessed whether overexpression of SATB2 in human normal prostate epithelial cells (PrECs) induces properties of cancer stem cells (CSCs). The results demonstrate that SATB2 is highly expressed in prostate cancer cell lines and CSCs, but not in PrECs. Overexpression of SATB2 in PrECs induces cellular transformation which was evident by the formation of colonies in soft agar and spheroids in suspension. Overexpression of SATB2 in PrECs also resulted in induction of stem cell markers (CD44 and CD133), pluripotency-maintaining transcription factors (cMYC, OCT4, SOX2, KLF4, and NANOG), CADHERIN switch, and EMT-related transcription factors. Chromatin immunoprecipitation assay demonstrated that SATB2 can directly bind to promoters of BCL-2, BSP, NANOG, MYC, XIAP, KLF4, and HOXA2, suggesting SATB2 is capable of directly regulating pluripotency/self-renewal, cell survival, and proliferation. Since prostate CSCs play a crucial role in cancer initiation, progression, and metastasis, we also examined the effects of SATB2 knockdown on stemness. SATB2 knockdown in prostate CSCs inhibited spheroid formation, cell viability, colony formation, cell motility, migration, and invasion compared to their scrambled control groups. SATB2 knockdown in CSCs also upregulated the expression of E-CADHERIN and inhibited the expression of N-CADHERIN, SNAIL, SLUG, and ZEB1. The expression of SATB2 was significantly higher in prostate adenocarcinoma compared to normal tissues. Overall, our data suggest that SATB2 acts as an oncogenic factor where it is capable of inducing malignant changes in PrECs by inducing CSC characteristics. [ABSTRACT FROM AUTHOR]

Krüppel-like factor 4 (KLF4), a zinc finger transcription factor, is found in different human tissues and shows diverse regulatory activities in a cell-dependent manner. In the brain, KLF4 controls various neurophysiological and neuropathological processes, and its contribution to various neurological diseases has been widely reported. Parkinson's disease (PD) is an age-related neurodegenerative disease that might have a connection with KLF4. In this review, we discussed the potential implication of KLF4 in fundamental molecular mechanisms of PD, including aberrant proteostasis, neuroinflammation, apoptosis, oxidative stress, and iron overload. The evidence collected herein sheds new light on KLF4-mediated pathways, which manipulation appears to be a promising therapeutic target for PD management. However, there is a gap in the knowledge on this topic, and extended research is required to understand the translational value of the KLF4-oriented therapeutical approach in PD. [ABSTRACT FROM AUTHOR]

Intestinal barrier dysfunction is an important contributor to morbidity caused by sepsis. This study investigates the molecular mechanism by which Ghrelin affects intestinal dysfunction in rat model of sepsis. A rat model of sepsis was established by cecal ligation and puncture (CLP), revealing that Ghrelin was downregulated when sepsis occurs. Increases in the levels of inflammatory factors tumor necrosis factor α (TNF-α), interleukin-1 (IL-1β), IL-6, gastrin, γ-H2AX and 8-OHdG was also detected in this model system, as was an overall increase in oxidative stress. Introduction of exogenous Ghrelin inhibited these increases in inflammatory response and oxidative stress, leading to a reduction of overall sepsis-induced intestinal dysfunction. Ghrelin was then shown to activate SIRT1 expression in vitro, while SIRT1 was found to co-express with KLF4, which in turn was predicted to bind to matrix metalloproteinase 2 (MMP2) promoter. Finally, gainand loss-of-function experiment demonstrated that SIRT1 upregulated the expression of KLF4 to downregulate MMP2. Collectively, Ghrelin inhibits the oxidative stress and intestinal dysfunction to attenuate sepsis by activating SIRT1 and regulating a KLF4/MMP2 regulatory axis. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) represents a significant global health burden, necessitating an in‐depth exploration of its molecular underpinnings to facilitate the development of effective therapeutic strategies. This investigation delves into the complex role of long non‐coding RNAs (lncRNAs) in the modulation of hypoxia‐induced HCC progression, with a specific emphasis on delineating and functionally characterizing the novel KLF4/Lnc18q22.2/ULBP3 axis. To elucidate the effects of hypoxic conditions on HCC cells, we established in vitro models under both normoxic and hypoxic environments, followed by lncRNA microarray analyses. Among the lncRNAs identified, Lnc18q22.2 was found to be significantly upregulated in HCC cells subjected to hypoxia. Subsequent investigations affirmed the oncogenic role of Lnc18q22.2, highlighting its critical function in augmenting HCC cell proliferation and migration. Further examination disclosed that Kruppel‐like factor 4 (KLF4) transcriptionally governs Lnc18q22.2 expression in HCC cells, particularly under hypoxic stress. KLF4 subsequently enhances the tumorigenic capabilities of HCC cells through the modulation of Lnc18q22.2 expression. Advancing downstream in the molecular cascade, our study elucidates a novel interaction between Lnc18q22.2 and UL16‐binding protein 3 (ULBP3), culminating in the stabilization of ULBP3 protein expression. Notably, ULBP3 was identified as a pivotal element, exerting dual functions by facilitating HCC tumorigenesis and mitigating immune evasion in hypoxia‐exposed HCC cells. The comprehensive insights gained from our research delineate a hitherto unidentified KLF4/Lnc18q22.2/ULBP3 axis integral to the understanding of HCC tumorigenesis and immune escape under hypoxic conditions. This newly unveiled molecular pathway not only enriches our understanding of hypoxia‐induced HCC progression but also presents novel avenues for therapeutic intervention. [ABSTRACT FROM AUTHOR]

To identify the anti-fibrosis effect of PRAS40 in scar, and its potential mechanism. We constructed a rat model of hypertrophic scarthat was locally injected the PRAS40 overexpression adenoviruses, mTORC1 inhibitor MHY1485 and activator rapamycin, and further observed the pathological changes of skin tissue and the severity of fibrosis by HE, Masson and sirius red staining, and analyzed the deposition of a-SMA and collagen I by western blot and immunofluorescence test. Meanwhile, the co-localization of KLF4 with a-SMA and type I collagen was analyzed, as well as the regulatory effect of PRAS40 on KLF4. In addition, we also verified whether the inhibition of scar fibrosis by PRAS40 is related to mTORC1, and whether the upregulation of KLF4 is related to mTORC1. The results showed that the expression of PRAS40 was low and p-PRAS40 was high in scar skin tissue. After local injection of PRAS40 overexpression adenovirus, the expression of PRAS40 in skin tissue was increased. The overexpression of PRAS40 can inhibit scar skin fibrosis and reduce the content of a-SMA and collagen I. Further mechanism analysis confirms that the inhibitory effect of PRAS40 on skin fibrosis is related to mTORC1, and PRAS40 inhibits the activation of mTORC1. The expression of KLF4 is relatively low in scar tissue. PRAS40 administration upregulated the expression of KLF4, which is related to mTORC1 PRAS40 significantly improves fibrosis of scar skin tissue and increases the expression of KLF4 in scars. The anti-fibrotic effect of PRAS40 depends on mTORC1. • Exogenous PRAS40 improved the scar fibrosis in the injured tissues of HS rats. • mTORC1 activation accelerates fibrosis degree in the injured skin. PRAS40 is also an inhibitor of mTORC1 inactivation, so we believe that the effect of PRAS40 on scar fibrosis is related to mTORC1. • KLF4 is an important regulator in the development of fibrosis. • Consistent with the previous report, we found a high expression of KLF4 in skin tissues , while after HS modeling, KLF4 was downregulated. Interestingly, PRAS40 could modulate the KLF4 expression, and this effect was also related to mTORC1. [ABSTRACT FROM AUTHOR]

Background: This study sought to assess the effect of statin therapy on myocardial inflammation in a White New Zealand rabbit model of atherogenesis. Methods: The mRNA expression levels of pro-inflammatory, pluripotency, and aging-related markers were quantified following a controlled feeding protocol and statin treatments. Results: Following high-cholesterol diet induction, we observed significant upregulation in the myocardial mRNA levels of MYD88, NF-κB, chemokines (CCL4, CCL20, and CCR2), IFN-γ, interleukins (IL-1β, IL-2, IL-4, IL-8, IL-10, and IL-18), and novel markers (klotho, KFL4, NANOG, and HIF1α). In contrast, HOXA5 expression was diminished following a hyperlipidemic diet. Both statin treatments significantly influenced the markers studied. Nevertheless, rosuvastatin administration resulted in a greater reduction in MYD88, NF-kB, chemokines (CCL4, CCL20, and CCR2), and interleukins IL-1β, IL-8, KLF4, NANOG, and HIF1α than fluvastatin. Fluvastatin, on the other hand, led to a stronger decrease in IL-4. Downregulation of IL-2 and IL-18 and upregulation of IFNβ and HOXA5 were comparable between the two statins. Notably, rosuvastatin had a stronger effect on the upregulation of klotho and IL-10. Conclusion: Overall, statin therapy significantly attenuated inflammatory, pluripotency, and klotho expression in myocardial tissue under atherogenic conditions. Our findings also highlight the differential efficacy of rosuvastatin over fluvastatin in curtailing proatherogenic inflammation, which could have profound implications for the clinical management of cardiovascular disease. [ABSTRACT FROM AUTHOR]

Aims: Myocardial ischaemia–reperfusion injury (MIRI) contributes to serious myocardial injury and even death. Long non‐coding RNAs (lncRNAs) have been reported to play pivotal roles in the occurrence and development of MIRI. Here, the detailed molecular mechanism of lncRNA SNHG1 in MIRI was explored. Methods and results: A cell model of MIRI was established through hypoxia/reoxygenation (H/R) stimulation. Cell viability and pyroptosis were evaluated utilizing MTT, PI staining, and flow cytometry. Interleukin (IL)‐1β and IL‐18 secretion levels were examined by ELISA. The gene and protein expression were detected by RT‐qPCR and western blot, respectively. Dual luciferase reporter gene, RIP and ChIP assays were performed to analyse the molecular interactions. The results showed that lncRNA SNHG1 overexpression alleviated H/R‐induced HL‐1 cell pyroptosis (all P < 0.05). LncRNA SNHG1 promoted KLF4 expression by sponging miR‐137‐3p. miR‐137‐3p silencing alleviated H/R‐induced pyroptosis in HL‐1 cells (all P < 0.05), which was abolished by KLF4 knockdown (all P < 0.05). KLF4 activated the AKT pathway by transcriptionally activating TRPV1 in HL‐1 cells (all P < 0.05). TRPV1 knockdown reversed the alleviation of SNHG1 upregulation on H/R‐induced pyroptosis in HL‐1 cells (all P < 0.05). Conclusions: These results showed that lncRNA SNHG1 assuaged cardiomyocyte pyroptosis during MIRI progression by regulating the KLF4/TRPV1/AKT axis through sponging miR‐137‐3p. Our findings may provide novel therapeutic targets for MIRI. [ABSTRACT FROM AUTHOR]

Background: The role and molecular mechanisms of collagen type VII (COL7A1) in cholangiocarcinoma (CCA) remain unknown. Methods: We analyzed the expression of COL7A1 in CCA and its relationship with patient prognosis using bioinformatic techniques. Expression levels of COL7A1 in CCA cells and tissues were detected using reverse transcription-quantitative PCR, western blotting, and immunohistochemistry. The effects of COL7A1 expression on the proliferation, migration, and invasion of CCA cells were assessed using CCK-8, colony formation, and Transwell assays. Bioinformatics and luciferase reporter gene assays were performed to examine the binding of KLF4 to COL7A1, and cytological experiments further verified the role of KLF4 in regulating the CCA phenotype through COL7A1. Xenograft mouse models were established to investigate the effects of COL7A1 on CCA tumor growth in vivo. Results: CCA tissues exhibited higher COL7A1 expression than normal bile duct tissues. There was no significant correlation between high or low COL7A1 expression and the survival time of patients with CCA. COL7A1 knockdown inhibited CCA cell proliferation, migration, and invasion. Furthermore, COL7A1 knockdown suppressed the activation of the PI3K/AKT signaling pathway. KLF4 can bind to COL7A1 and regulate COL7A1 expression, which in turn regulates the PI3K/AKT signaling pathway and impacts the proliferation and metastasis of CCA cells. Conclusion: Our findings suggest that KLF4 regulates CCA cell proliferation, migration, and invasion via the COL7A1/PI3K/AKT axis.

Inflammation is the response of the human body to injury, infection, or other abnormal states, which is involved in the development of many diseases. As a member of the Krüppel-like transcription factors (KLFs) family, KLF4 plays a crucial regulatory role in physiological and pathological processes due to its unique dual domain of transcriptional activation and inhibition. A growing body of evidence has demonstrated that KLF4 plays a pivotal role in the pathogenesis of various inflammatory disorders, including inflammatory bowel disease, osteoarthritis, renal inflammation, pneumonia, neuroinflammation, and so on. Consequently, KLF4 has emerged as a promising new therapeutic target for inflammatory diseases. This review systematically generalizes the molecular regulatory network, specific functions, and mechanisms of KLF4 to elucidate its complex roles in inflammatory diseases. An in-depth study on the biological function of KLF4 is anticipated to offer a novel research perspective and potential intervention strategies for inflammatory diseases.

The epigenetic layer of regulation has become increasingly relevant in the research focused on tumor suppressors. KLF4 is a well-described zinc-finger transcription factor, mainly known for its role in the acquisition of cell pluripotency. Here we report and describe the most relevant epigenetic regulation mechanisms that affect KLF4 expression in tumors. CpG island methylation emerges as the most common mechanism in several tumors including lung adenocarcinoma, hepatocellular carcinoma, non-Hodgkin lymphomas, among others. Further layers of regulation represented by histone methylation and acetylation and by non-coding RNAs are described. Overall, KLF4 emerges as a crucial target in the fight against cancer.

It is imperative to develop and implement newer, more effective strategies to address refractory diabetic wounds. As of now, there is currently no optimal solution for these wounds. Hypoxic human umbilical vein endothelial cells (HUVECs)-derived exosomes have been postulated to promote diabetic wound healing, however, its effect and molecular mechanism need further study. In this study, we aimed to investigate whether hypoxic exosomes enhance wound healing in diabetics. Based on our high-throughput sequencing, differentially expressed lncRNAs (including 64 upregulated lncRNAs and 94 downregulated lncRNAs) were found in hypoxic exosomes compared to normoxic exosomes. Interestingly, lncHAR1B was one of the prominently upregulated lncRNAs in hypoxic exosomes, showing a notable correlation with diabetic wound healing. More specifically, hypoxic exosomes were transmitted to surrounding cells, which resulted in a significant increase in lncHAR1B level, thereby relieving the dysfunction of endothelial cells and promoting the switch from M1 to M2 macrophages under high glucose conditions. Mechanistically, lncHAR1B directly interacted with the transcription factor basic helix-loop-helix family member e23 (BHLHE23), which subsequently led to its binding to the KLF transcription factor 4 (KLF4) and promoted KLF4 expression. In our in vivo experiments, the use of hypoxic exosomes-loaded HGM-QCS hydrogels (Gel-H-Exos) resulted in rapid wound healing compared to that of normoxic exosomes-loaded HGM-QCS hydrogels (Gel-N-Exos) and diabetic groups. Consequently, our study provides potentially novel therapeutic approaches aimed at accelerating wound healing and developing a practical exosomes delivery platform.

Meningiomas, the most common primary brain tumors in adults, are often benign and curable by surgical resection. However, a subset is of higher grade, shows aggressive growth behavior as well as brain invasion, and often recurs even after several rounds of surgery. Increasing evidence suggests that tumor classification and grading primarily based on histopathology do not always accurately predict tumor aggressiveness and recurrence behavior. The underlying biology of aggressive treatment-resistant meningiomas and the impact of specific genetic aberrations present in these high-grade tumors is still only insufficiently understood. Therefore, an in-depth research into the biology of this tumor type is warranted. More recent studies based on large-scale molecular data such as whole exome/genome sequencing, DNA methylation sequencing, and RNA sequencing have provided new insights into the biology of meningiomas and have revealed new risk factors and prognostic subtypes. The most common genetic aberration in meningiomas is functional loss of NF2 and occurs in both low- and high-grade meningiomas, whereas NF2-wildtype meningiomas are enriched for recurrent mutations in TRAF7, KLF4, AKT1, PI3KCA, and SMO and are more frequently benign. Most meningioma mouse models are based on patient-derived xenografts and only recently have new genetically engineered mouse models of meningioma been developed that will aid in the systematic evaluation of specific mutations found in meningioma and their impact on tumor behavior. In this article, we review recent advances in the understanding of meningioma biology and classification and highlight the most common genetic mutations, as well as discuss new genetically engineered mouse models of meningioma.

Abstract Improving drug sensitivity is an important strategy in chemotherapy of cancer and accumulating evidence indicates that miRNAs are involved in the regulation of drug sensitivity, but the specific mechanism is still unclear. Our previous study has found that miR-296-5p was significantly downregulated in nasopharyngeal carcinoma (NPC). Here, we aim to explore whether miR-296-5p is involved in regulating cisplatin sensitivity in NPC by regulating STAT3/KLF4 signaling axis. The cell proliferation and clonogenic capacity of NPC cells were evaluated by CCK8 Assay and plate colony assay, respectively. The Annexin V-FITC staining kit was used to determine and quantify the apoptotic cells using flow cytometry. The drug efflux ability of NPC cells were determined by Rhodamine 123 efflux experiment. The expression of miR-296-5p, apoptosis-related genes and protein in NPC cell lines were detected by qPCR and Western blot, respectively. Animal study was used to evaluate the sensitivity of NPC cells to DDP treatment in vivo. Our results showed that elevated miR-296-5p expression obviously promoted the sensitivity of NPC cells to DDP by inhibiting cell proliferation and clonogenic capacity, and inducing apoptosis. In addition, we found that miR-296-5p inhibited the expression of STAT3 and KLF4 in NPC cells, while overexpression of exogenous STAT3 reversed miR-296-5p-mediated enhancement in cell death of DDP-treated NPC cells. In vivo studies further confirmed that miR-296-5p promotes the sensitivity of NPC cells to DDP treatment. miRNA-296-5p enhances the drug sensitivity of nasopharyngeal carcinoma cells to cisplatin via STAT3/KLF4 signaling pathway.

Ummul Khair Imaduddin,1 Afiat Berbudi,2,&ast; Enny Rohmawaty3,&ast; 1Graduate School of Master Program in Anti Aging and Aesthetic Medicine, Faculty of Medicine, Universitas Padjadjaran, Bandung, West Java, Indonesia; 2Parasitology Division, Department of Biomedical Sciences, Faculty of Medicine, Universitas Padjadjaran, Bandung, West Java, Indonesia; 3Pharmacology & Therapy Division, Departement of Biomedical Sciences, Faculty of Medicine, Universitas Padjadjaran, Bandung, West Java, Indonesia&ast;These authors contributed equally to this workCorrespondence: Enny Rohmawaty, Pharmacology & Therapy Division, Department of Biomedical Sciences, Faculty of Medicine, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang, KM.21, Hegarmanah, Kec. Jatinangor, Kabupaten Sumedang, Bandung, West Java, 45363, Indonesia, Email e.rohmawaty@unpad.ac.idPurpose: To explore the potential therapeutic effects of Physalis angulata L. (Ciplukan) extract on lung fibrosis resolution in a Bleomycin-induced mouse model, researchers conducted a comprehensive study. The study focused on key genes associated with fibrosis progression, including Nox4, Mmp8, Klf4, and FAS, and assessed their mRNA expression levels following the administration of Ciplukan extract.Methods: A Bleomycin-induced mice model was divided into seven groups to investigate the effects of ciplukan extract on fibrosis-related gene expressions. Mice were induced with subcutaneously injected Bleomycin to generate lung fibrosis and given different doses of the Ciplukan extract for four weeks. Lung fibrosis mRNA expression was analyzed by semi-quantitative PCR for Nox4, Klf4, Mmp8, and FAS.Results: The administration of ciplukan extract resulted in a significant decrease in mRNA expression of Nox4 with p-value=0.000, Mmp8 with p-value =0.002, and Klf4 with p-value =0.007, indicating potential antifibrotic effects. However, FAS expression remained unchanged (p-value=0.127).Conclusion: Ciplukan extract exhibited promising effects on fibrosis-related gene expressions, particularly Nox4, Mmp8, and Klf4. This study suggests that the extract has the potential to intervene in fibrosis progression, offering a potential avenue for therapeutic strategies.Keywords: ciplukan, FAS, Klf4, lung fibrosis, Mmp8, Nox4, pulmonary fibrosis, Physalis angulata L

Idiopathic pulmonary fibrosis (IPF) is a lethal progressive disease with elusive molecular mechanisms and limited therapeutic options. Aberrant activation of fibroblasts is a central hallmark of lung fibrosis. Here, we report that Golgi membrane protein 1 (GOLM1, also known as GP73 or GOLPH2) was increased in the lungs of patients with pulmonary fibrosis and mice with bleomycin (BLM)–induced pulmonary fibrosis. Loss of GOLM1 inhibited proliferation, differentiation, and extracellular matrix deposition of fibroblasts, whereas overexpression of GOLM1 exerted the opposite effects. Similarly, worsening pulmonary fibrosis after BLM treatment was observed in GOLM1–knock-in mice, whereas BLM-treated Golm1-knockout mice exhibited alleviated pulmonary fibrosis and collagen deposition. Furthermore, we identified long noncoding RNA NEAT1 downstream of GOLM1 as a potential mediator of pulmonary fibrosis through increased GOLM1 expression. Depletion of NEAT1 inhibited fibroblast proliferation and extracellular matrix production and reversed the profibrotic effects of GOLM1 overexpression. Additionally, we identified KLF4 as a downstream mediator of GOLM1 signaling to NEAT1. Our findings suggest that GOLM1 plays a pivotal role in promoting pulmonary fibrosis through the GOLM1–KLF4–NEAT1 signaling axis. Targeting GOLM1 and its downstream pathways may represent a novel therapeutic strategy for treating pulmonary fibrosis. [ABSTRACT FROM AUTHOR]

The transcription factor Kruppel-like factor 4 (KLF4) regulates the expression of immunosuppressive and anti-thrombotic proteins. Despite its importance in maintaining homeostasis, the signals that control its expression and the mechanism of its transactivation remain unclarified. CD55 [aka decay accelerating factor (DAF)], now known to be a regulator of T and B cell responses, biases between pro- and anti-inflammatory processes by controlling autocrine C3a and C5a receptor (C3ar1/C5ar1) signaling in cells. The similarity in CD55's and KLF4's regulatory effects prompted analyses of their functional relationship. In vascular endothelial cells (ECs), CD55 upregulation accompanied KLF4 expression via a p-CREB and CREB Binding Protein (CBP) mechanism. In both ECs and macrophages, CD55 expression was essential for KLF4's downregulation of pro-inflammatory/pro-coagulant proteins and upregulation of homeostatic proteins. Mechanistic studies showed that upregulation of KLF4 upregulated CD55. The upregulated CD55 in turn enabled the recruitment of p-CREB and CBP to KLF4 needed for its transcription. Activation of adenylyl cyclase resulting from repression of autocrine C3ar1/C5ar1 signaling by upregulated CD55 concurrently led to p-CREB and CBP recruitment to KLF4-regulated genes, thereby conferring KLF4's transactivation. Accordingly, silencing CD55 in statin-treated HUVEC disabled CBP transfer from the E-selectin to the eNOS promoter. Importantly, silencing CD55 downregulated KLF4's expression. It did the same in untreated HUVEC transitioning from KLF4low growth to KLF4hi contact inhibition. KLF4's and CD55's function in ECs and macrophages thus are linked via a novel mechanism of gene transactivation. Because the two proteins are co-expressed in many cell types, CD55's activity may be broadly tied to KLF4's immunosuppressive and antithrombotic activities. [ABSTRACT FROM AUTHOR]

Introduction: Ulcerative colitis (UC) is one of the most common diseases in the gastrointestinal tract related to abnormal inflammation. Pyroptosis, which is characterized by the formation of inflammasome, activation of caspase-1, and separation of N- and C-terminus of gasdermin D (GSDMD), and may be involved in the pathogenesis of IBD. Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor expressed in differentiated epithelial cells. KLF4 mediates proinflammatory signaling in macrophages. Here, we tested whether KLF4 is functional in pyroptosis of UC. Methods: In human UC tissues and/or lipopolysaccharide (LPS)/adenosine 5-triphosphate (ATP) stimulation human colon epithelial cells, KLF4, TXNIP, Cleave-Caspase-1, and GSDMD expression were detected through quantitative reverse transcription polymerase chain reaction (PCR), immunohistochemical and western blot assay. Interleukin (IL)-1ß and IL-18 levels were quantified by enzyme-linked immunosorbent assay. We successfully constructed a KLF4-silenced colon epithelial cell line using an adenovirus vector. We apply the UCSC and JASPAR to predict the KLF4 binding sites in the promoter region of TXNIP. Results: In human UC tissues and/or LPS/ATP stimulation human colon epithelial cells, KLF4, TXNIP, Caspase-1, and GSDMD expression level were significantly elevated via quantitative reverse transcription PCR, immunohistochemical and western blot assay. Moreover, We identified that there is an interaction between KLF4 and TXNIP through Yeast double hybrid assay and CO-IP assay. We successfully constructed a KLF4-silenced human intestinal epithelial cell line. In LPS/ATP stimulation KLF4-silenced human intestinal epithelial cells, KLF4, TXNIP, Cleave Caspase-1, ASC, and GSDMD expression level were significantly decreased via quantitative reverse transcription PCR. Conclusion: Our results confirm that KLF4 can positively regulate the expression of TXNIP and regulate the pyroptosis process of UC through the TXNIP/NLRP3 pathway. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion To explore the expression and functional role of Krüpple‐like factor 4 (KLF4) protein stimulated by tumor necrosis factor α (TNF‐α) in SK‐BR‐3 breast cancer cells.SK‐BR‐3 cells were stimulated with various concentrations of TNF‐α at 0, 1, 5, 10, and 20 ng/mL. Expression levels of KLF4 protein were detected by Western blotting. In the detection of apoptosis, flow cytometry, and DAPI staining were used for detecting the level of apoptosis.KLF4 expression was markedly elevated following stimulation of SK‐BR‐3 with TNF‐α. At the same time, the expression of KLF4 protein increased gradually with the increase of TNF‐α stimulation concentration. TNF‐α stimulation of SK‐BR‐3 cells increased apoptosis as measured by apoptosis levels. By overexpressing KLF4 protein in SK‐BR‐3 cells, it similarly increased apoptosis and promoted cell death of SK‐BR‐3 cells.TNF‐α promotes KLF4 expression, while TNF‐α promotes apoptosis in SK‐BR‐3 cells, a process that may be due to elevated KLF4 protein expression. [ABSTRACT FROM AUTHOR]

Introduction: Osteoarthritis (OA) is a common degenerative disease of joints, which can appear in almost any joint of the body. Therefore, the widespread occurrence of this disease has a huge impact on the lives of patients around the world. As an important part of metabolism, lipid metabolism is closely related to the occurrence and development of osteoarthritis. Method: We screened UGCG and KLF4 based on weighted co-expression network analysis (WGCNA) and SVM-REF analysis. The data from Gene Expression Omnibus (GEO) and single-cell data verified the expression of these two genes. We analyzed KLF4-related genes and established a diagnosis model of OA related to lipid metabolism through the least absolute shrinkage and selection operator (LASSO) analysis. RT-PCR was used to verify the expression of KLF4 in osteoarthritis. Results: Ten important lipid metabolism related genes (LMRGs) in OA were obtained. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that they are involve in the formation of immune microenvironment in osteoarthritis. CIBERSORT analysis revealed that there were significant differences in the immune microenvironment between osteoarthritis patients and normal controls. RT-PCR results showed that the expression of KLF4 in OA samples was lower than that in normal samples. The diagnostic model can be used to diagnose OA patients well. Conclusions: Overall, we demonstrated the potential relationship between the abnormal lipid metabolism and the pathological process of OA. Finally, we identified KLF4 as our significant LMRG and constructed a KLF4-related scoring model to accurately diagnose OA. In conclusion, therapy strategies targeting on regulating lipid metabolism may become a key factor in treating OA. Key Points (a) We identified the significant LMRG KLF4 and constructed a novel KLF4-related scoring model for the accuracy diagnosis of OA. (b) The potential relationship between lipid metabolism and the immune microenvironment in OA was demonstrated in our research. (c) The relationship of lipid metabolism and OA has been further improved in our research and provided novel insight for the diagnosis and therapy for OA patients. [ABSTRACT FROM AUTHOR]

Background: Polycystic ovary syndrome (PCOS) is defined as a complex endocrinopathy greatly affecting reproductive-aged women. Krüppel-like factors (KLFs) are involved in female reproduction. Objectives: Our study expounded the functions of KLF4 on proliferation and apoptosis of ovarian granulosa cells (GCs) in PCOS via regulating Runt-related transcription factor 2 (RUNX2). Results: KLF4 and RUNX2 were under-expressed in testosterone (TTR)-induced KGN cell models. KLF4 overexpression facilitated KGN cell proliferation and suppressed KGN cell apoptosis. KLF4 bound to the RUNX2 promoter and increased RUNX2 expression level. Furthermore, RUNX2 suppression counteracted the functions of KLF4 overexpression on KGN cells. Conclusion: KLF4 overexpression promoted RUNX2 expression by binding to the RUNX2 promoter, thereby further accelerating GC proliferation and repressing GC apoptosis in PCOS. [ABSTRACT FROM AUTHOR]

Chromatin accessibility remodeling driven by pioneer factors is critical for the development of early embryos. Current studies have illustrated several pioneer factors as being important for agricultural animals, but what are the pioneer factors and how the pioneer factors remodel the chromatin accessibility in porcine early embryos is not clear. By employing low-input DNase-seq (liDNase-seq), we profiled the landscapes of chromatin accessibility in porcine early embryos and uncovered a unique chromatin accessibility reprogramming pattern during porcine preimplantation development. Our data revealed that KLF4 played critical roles in remodeling chromatin accessibility in porcine early embryos. Knocking down of KLF4 led to the reduction of chromatin accessibility in early embryos, whereas KLF4 overexpression promoted the chromatin openness in porcine blastocysts. Furthermore, KLF4 deficiency resulted in mitochondrial dysfunction and developmental failure of porcine embryos. In addition, we found that overexpression of KLF4 in blastocysts promoted lipid droplet accumulation, whereas knockdown of KLF4 disrupted this process. Taken together, our study revealed the chromatin accessibility dynamics and identified KLF4 as a key regulator in chromatin accessibility and cellular metabolism during porcine preimplantation embryo development. [ABSTRACT FROM AUTHOR]

Previous in vivo and in vitro studies have demonstrated a dramatic up-regulation of Krüppel-like factor 4 (Klf4) in rat preovulatory granulosa cells (GCs) after LH/hCG treatment and its role in regulating Cyp19A1 expression during the luteal shift in steroidogenesis. In this study, we examined whether Klf4 also mediates the LH-induced repression of Cyp17A1 expression in primary rat preovulatory GCs. In response to LH treatment of GCs in vitro, Cyp17A1 expression declined to less than half of its initial value by 1 h, remaining low for 24 h of culture. Overexpression of Klf4 decreased basal and Sf1-induced Cyp17A1 expressions and increased progesterone secretion. Reduction of endogenous Klf4 by siRNA elevated basal Cyp17A1 expression but did not affect LH-stimulated progesterone production. Overexpression of Klf4 also significantly attenuated Sf1-induced Cyp17A1 promoter activity. On the other hand, mutation of the conserved Sp1/Klf binding motif in the promoter revealed that this motif is not required for Klf4-mediated repression. Taken together, these data indicate that the Cyp17A1 gene may be one of the downstream targets of Klf4, which is induced by LH in preovulatory GCs. This information may help in identifying potential targets for preventing the molecular changes occurring in hyperandrogenic disorders. [ABSTRACT FROM AUTHOR]

Obesity is characterized by excessive accumulation of adipose tissue (mainly visceral). The morphology and function of mitochondria are crucial for regulating adipose browning and weight loss. Research suggests that the SGLT2 inhibitor canagliflozin may induce weight loss through an unknown mechanism, particularly targeting visceral adipose tissue. While Krueppel-Like Factor 4 (KLF4) is known to be essential for energy metabolism and mitochondrial function, its specific impact on visceral adipose tissue remains unclear. We administered canagliflozin to db/db mice for 8 weeks, or exposed adipocytes to canagliflozin for 24 h. The expression levels of browning markers, mitochondrial dynamics, and KLF4 were assessed. Then we validated the function of KLF4 through overexpression in vivo and in vitro. Adenosine monophosphate-activated protein kinase (AMPK) agonists, inhibitors, and KLF4 si-RNA were employed to elucidate the relationship between AMPK and KLF4. The findings demonstrated that canagliflozin significantly decreased body weight in db/db mice and augmented cold-induced thermogenesis. Additionally, canagliflozin increased the expression of mitochondrial fusion-related factors while reducing the levels of fission markers in epididymal white adipose tissue. These consistent findings were mirrored in canagliflozin-treated adipocytes. Similarly, overexpression of KLF4 in both adipocytes and db/db mice yielded comparable results. In all, canagliflozin mitigates obesity in db/db mice by promoting the brown visceral adipocyte phenotype through enhanced mitochondrial fusion via AMPK/KLF4 signaling. [Display omitted] • Canagliflozin regulates mitochondrial dynamics and induces browning of visceral adipose tissue in db/db mice. • Overexpression of KLF4 in visceral adipose tissue exhibit a browning phenotype and stimulate mitochondrial fusion. • Canagliflozin regulates adipocyte browning and mitochondrial dynamics through AMPK/KLF4 signaling. [ABSTRACT FROM AUTHOR]