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Background/purpose: Oral submucous fibrosis (OSF) is a condition characterized by inflammation and excessive collagen deposition, which has been identified as a potentially malignant disorder. Recently, several microRNAs (miRNAs) have been shown to be implicated in various disorders associated with fibrosis. However, how these miRNAs modulate OSF development is poorly understood. Therefore, the study aimed to identify the specific miRNAs that contribute to the progression of OSF and to investigate their molecular mechanisms in promoting fibrosis. Materials and methods: The expression and clinical significance of potential pro-fibrosis miRNA in the OSF cohort and primary buccal mucosal fibroblasts were confirmed through RNA sequencing and qRT–PCR. Luciferase reporter activity assay, miRNA mimic or inhibitor, and short-hairpin RNA silencing were used to elucidate the molecular mechanism of miRNA. Transwell migration, collagen contraction, and reactive oxygen species (ROS) generation detection were used to investigate the effects of this mechanism on the myofibroblast phenotype and cellular pro-fibrosis capacity. Results: This study demonstrated that miR-190a was overexpressed in fibrotic buccal mucosal fibroblasts (fBMFs). Transfecting fBMFs with miR-190a inhibitor resulted in reduced cell migration, collagen gel contraction, ROS generation, and expression of fibrotic markers. Furthermore, miR-190a exerted this pro-fibrosis property by direct binding to its target, Krüppel-like factor 15 (KLF15). The results also indicated that the aberrant upregulation of miR-190a, in turn, downregulated the expression of KLF15, which resulted in the activation of myofibroblast. Conclusion: Our findings demonstrated that miR-190a was involved in myofibroblast activation, suggesting that targeting the miR-190a/KLF15 axis may be a feasible approach in the therapy of OSF.

Renal unilateral ischemia-reperfusion injury (UIRI) constitutes a significant global health challenge, with poor recovery leading to chronic kidney disease and subsequent renal fibrosis. Extracellular vesicles (EVs) present substantial potential benefits for renal diseases. However, the limited yield and efficacy of EVs produced through traditional methodologies (2D-EVs) severely restrict their widespread application. Moreover, the efficient and effective strategies for using EVs in UIRI treatment and their mechanisms remain largely unexplored. In this study, we propose an innovative approach by integrating bioprinted mesenchymal stem cell microfiber extracellular vesicles production technology (3D-EVs) with a tail vein injection method, introducing a novel treatment strategy for UIRI. Our comparison of the biological functions of 2D-EVs and 3D-EVs, both in vitro and in vivo, reveals that 3D-EVs significantly outperform 2D-EVs. Specifically, in vitro, 3D-EVs demonstrate a superior capacity to enhance the proliferation and migration of NRK-52E cells and mitigate hypoxia/reoxygenation (H/R)-induced injuries by reducing epithelial-mesenchymal transformation, extracellular matrix deposition, and ferroptosis. In vivo, 3D-EVs exhibit enhanced therapeutic effects, as evidenced by improved renal function and decreased collagen deposition in UIRI mouse kidneys. We further elucidate the mechanism by which 3D-EVs derived from KLF15 ameliorate UIRI-induced tubular epithelial cells (TECs) ferroptosis through the modulation of SLC7A11 and GPX4 expression. Our findings suggest that bioprinted mesenchymal stem cells microfiber-derived EVs significantly ameliorate renal UIRI, opening new avenues for effective and efficient EV-based therapies in UIRI treatment.

The impaired endometrial receptivity is a major factor contributing to infertility in patients with endometriosis (EM), but the underlying mechanism remains unclear. Qur study aimed to investigate the role of Kruppel-like factor 15 (KLF15) in endometrial receptivity and its regulation in EM. We observed a significant decrease in KLF15 expression in the mid-secretory epithelial endometrial cells of EM patients compared to normal females without EM. To confirm the role of KLF15 in endometrial receptivity, we found a significantly reduced KLF15 expression and a significant decrease in embryo implantation number in the rat model via uterine horn infection with siRNA. This highlights the importance of KLF15 as a regulator receptivity. Furthermore, through ChIP-qPCR, we discovered that the progesterone receptor (PR) directly binds to KLF15 promoter regions, indicating that progesterone resistance may mediate the decrease in KLF15 expression in EM patients. Additionally, we found that the mid-secretory endometrium of EM patients exhibited impaired epithelial-mesenchymal transition (EMT). Knockdown of KLF15 upregulated E-cadherin and downregulated vimentin expression, leading to inhibited invasiveness and migration of Ishikawa cells. Qverexpression KLF15 promotes EMT, invasiveness, and migration ability, and increases the attachment rate of JAR cells to Ishikawa cells. Through RNA-seq analysis, we identified TWIST2 as a downstream gene of KLF15. We confirmed that KLF15 directly binds to the promoter region of TWIST2 via ChIP-qPCR, promoting epithelial cell EMT during the establishment of endometrial receptivity. Qur study reveals the involvement of KLF15 in the regulation of endometrial receptivity and its downstream effects on EMT. These findings provide valuable insights into potential therapeutic approaches for treating non-receptive endometrium in patients with EM. [ABSTRACT FROM AUTHOR]

Endothelial cell damage and dysfunction are crucial factors in the development and early stages of coronary artery disease (CAD) and apoptosis plays a significant role in this process. In this study, We aimed to simulate the CAD vascular microenvironment by treating endothelial cells with tumor necrosis factor alpha (TNF-α) to construct an endothelial cell apoptosis model. Our findings revealed that the TNF-α model resulted in increased micro-RNA 223-3p (miR-223-3p) mRNA and Bax protein expression, decreased kruppel-like factor 15 (KLF15) and Bcl-2 protein expression, and decreased cell viability. More importantly, in the TNF-α-induced endothelial cell apoptosis model, transfection with the miR-223-3p inhibitor reversed the effects of TNF-α on Bcl-2, Bax expression. We transfected miRNA-223-3p mimics or inhibitors into endothelial cells and assessed miR-223-3p levels using RT-PCR. Cell viability was detected using CCK8. Western blot technology was used to detect the expression of Bcl-2, Bax, and KLF15. In summary, this study demonstrates the role and possible mechanism of miR-223-3p in endothelial cells during CAD, suggesting that miR-223-3p may serve as a promising therapeutic target in CAD by regulating KLF15. [ABSTRACT FROM AUTHOR]

Macrophage-derived foam cells are a hallmark of atherosclerosis. Scavenger receptors, including lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (OLR-1), are the principal receptors responsible for the uptake and modification of LDL, facilitating macrophage lipid load and the uptake of oxidized LDL by arterial wall cells. Krüppel-like factor 15 (KLF15) is a transcription factor that regulates the expression of genes by binding to the promoter during transcription. Therefore, this study aimed to investigate the precise role of macrophage KLF15 in atherogenesis. We used two murine models of atherosclerosis: mice injected with an adeno-associated virus (AAV) encoding the Asp374-to-Tyr mutant version of human PCSK9, followed by 12 weeks on a high-fat diet (HFD), and ApoE −/ −‐ mice on a HFD. We subsequently injected mice with AAV- KLF15 and AAV- LacZ to assess the role of KLF15 in the development of atherosclerosis in vivo. Oil Red O, H&E, and Masson's trichome staining were used to evaluate atherosclerotic lesions. Western blots and RT-qPCR were used to assess protein and mRNA levels, respectively. We determined that KLF15 expression was downregulated during atherosclerosis formation, and KLF15 overexpression prevented atherosclerosis progression. KLF15 expression levels did not affect body weight or serum lipid levels in mice. However, KLF15 overexpression in macrophages prevented foam cell formation by reducing OLR-1-meditated lipid uptake. KLF15 directly targeted and transcriptionally downregulated OLR-1 levels. Restoration of OLR-1 reversed the beneficial effects of KLF15 in atherosclerosis. Macrophage KLF15 transcriptionally downregulated OLR-1 expression to reduce lipid uptake, thereby preventing foam cell formation and atherosclerosis. Thus, our results suggest that KLF15 is a potential therapeutic target for atherosclerosis. [Display omitted] • KLF15 expression in macrophages was downregulated during atherosclerosis. • The progression of atherosclerosis was attenuated by KLF15 overexpression. • KLF15 overexpression prevented increased macrophage lipid deposition and foam cell formation. • Downregulation of KLF15 expression promoted macrophage foam cell formation. • Macrophage KLF15 transcriptionally downregulated OLR-1 expression by binding to its promoter. [ABSTRACT FROM AUTHOR]

Kruppel-like factor 15 (KLF15) is involved in many cardiovascular diseases and is abnormally expressed in atherosclerosis (AS), but the regulatory mechanism of KLF15 in AS has not been reported so far. RT-qPCR was used to detect the expression of KLF15 and ATG14 in AS patients. Subsequently, human aortic endothelial cells (HAECs) were induced by oxidized low densitylipoprotein (ox-LDL), and the expression of KLF15 in model cells was detected. KLF15 was overexpressed in cells by lipofection transfection, and then CCK8, flow cytometry, Western blot, ELISA, and related assay kits were used to detect cell viability, apoptosis, inflammatory response as well as oxidative stress, respectively. The targeted regulatory relationship between KLF15 and autophagy-related 14 (ATG14) was detected by ChIP and luciferase reporter assays. Following ATG14 silencing in KLF15-overexpressing cells, immunofluorescence and Western blot were used to detect the autophagy. Finally, after the addition of 3-Methyladenine (3-MA), an autophagy inhibitor, the aforementioned experiments were conducted again to further explore the mechanism. The expression of KLF15 and ATG14 were decreased in AS patients and ox-LDL-induced HAECs. Overexpression of KLF15 protected ox-LDL-induced HAECs from damage, which might be achieved through transcriptional regulation of ATG14. In addition, KLF15 could promote autophagy through transcriptional activation of ATG14. KLF15 transcriptionally activated ATG14 to promote autophagy and attenuate damage of ox-LDL-induced HAECs. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) is a common and serious disease with high morbidity and mortality, and its pathophysiological mechanisms are not fully understood. Increasing evidence suggests an important role of ferroptosis in AKI. Krüppel-like factor 15 (KLF15) is a transcription factor involved in several metabolic diseases, but its role in AKI and ferroptosis remains unclear. In this study, we explored the potential role of KLF15 using a folic acid-induced AKI model. Our study showed that KLF15 expression was reduced in kidney tissues of AKI mice, and KLF15 knockout exacerbated folic acid-induced ferroptosis and kidney injury. In vitro studies revealed that the ferroptosis inducer erastin significantly suppressed KLF15 expression in human tubular epithelial cells. Notably, the overexpression of KLF15 attenuated ferroptosis, as evidenced by a decrease in the lipid peroxidation marker of malondialdehyde and the upregulation of glutathione peroxidase 4 (GPX4), while KLF15 knockdown with shRNA exerted the opposite effect. Mechanistically, KLF15 stabilized the protein of nuclear factor erythroid 2-related factor 2 (NRF2) and subsequently increased the GPX4 level. Collectively, KLF15 plays an important role in the modulation of ferroptosis in AKI and may be a potential therapeutic target for treating AKI. [ABSTRACT FROM AUTHOR]

Abstract Background Excessive abdominal fat deposition in commercial broilers presents an obstacle to profitable meat quality, feed utilization, and reproduction. Abdominal fat deposition depends on the proliferation of preadipocytes and their maturation into adipocytes, which involves a cascade of regulatory molecules. Accumulating evidence has shown that microRNAs (miRNAs) serve as post-transcriptional regulators of adipogenic differentiation in mammals. However, the miRNA-mediated molecular mechanisms underlying abdominal fat deposition in chickens are still poorly understood. This study aimed to investigate the biological functions and regulatory mechanism of miRNAs in chicken abdominal adipogenesis. Results We established a chicken model of abdominal adipocyte differentiation and analyzed miRNA and mRNA expression in abdominal adipocytes at different stages of differentiation (0, 12, 48, 72, and 120 h). A total of 217 differentially expressed miRNAs (DE-miRNAs) and 3520 differentially expressed genes were identified. Target prediction of DE-miRNAs and functional enrichment analysis revealed that the differentially expressed targets were significantly enriched in lipid metabolism-related signaling pathways, including the PPAR signaling and MAPK signaling pathways. A candidate miRNA, gga-miR-106-5p, exhibited decreased expression during the proliferation and differentiation of abdominal preadipocytes and was downregulated in the abdominal adipose tissues of fat chickens compared to that of lean chickens. gga-miR-106-5p was found to inhibit the proliferation and adipogenic differentiation of chicken abdominal preadipocytes. A dual-luciferase reporter assay suggested that the KLF15 gene, which encodes a transcriptional factor, is a direct target of gga-miR-106-5p. gga-miR-106-5p suppressed the post-transcriptional activity of KLF15, which is an activator of abdominal preadipocyte proliferation and differentiation, as determined with gain- and loss-of-function experiments. Conclusions gga-miR-106-5p functions as an inhibitor of abdominal adipogenesis by targeting the KLF15 gene in chickens. These findings not only improve our understanding of the specific functions of miRNAs in avian adipogenesis but also provide potential targets for the genetic improvement of excessive abdominal fat deposition in poultry.

Background: Accumulating evidence indicates that circular RNAs (circRNAs) play important roles in various cancers. Hsa_circ_0008832 (circFBXO7) is a circRNA generated from the second exon of the human F-box only protein 7 (FBXO7). Mouse circFbxo7 is a circRNA generated from the second exon of mouse F-box only protein 7 (Fbxo7). The role of human circFBXO7 and mouse circFbxo7 in non-small cell lung cancer (NSCLC) has not been reported. Methods: The expression of circFBXO7 was measured by quantitative real-time PCR. Survival analysis was performed to explore the association between the expression of circFBXO7 and the prognosis of patients with NSCLC. Lung cancer cell lines were transfected with plasmids. Cell proliferation, cell cycle, and tumorigenesis were evaluated to assess the effects of circFBXO7. Fluorescence in situ hybridization assay was used to identify the location of circFBXO7 and circFbxo7 in human and mouse lung cancer cells. Luciferase reporter assay was conducted to confirm the relationship between circFBXO7 and microRNA. Results: In this study, we found that circFBXO7 was downregulated in NSCLC tissues and cell lines. NSCLC patients with high circFBXO7 expression had prolonged overall survival. Overexpression of circFBXO7 inhibited cell proliferation both in vitro and in vivo. Mechanistically, we demonstrated that circFBXO7 upregulated the expression of miR-296-3p target gene Krüppel-like factor 15 (KLF15) and KLF15 transactivated the expression of CDKN1A. Conclusions: CircFBXO7 acts as a tumor suppressor by a novel circFBXO7/miR-296-3p/KLF15/CDKN1A axis, which may serve as a potential biomarker and therapeutic target for NSCLC.

The circadian clock is an intricate molecular network that paces a variety of physiological process to ~ 24 hour day/night cycles. Whereas the central circadian clock in the brain is primarily entrained by light signals, peripheral circadian clocks, which are in most cells in the body, receive cues not only from the central pacemaker but also endocrine and other systemic and tissue-specific signals. Prior studies have connected peripheral circadian clocks to metabolism, primarily with studies focused on the robust clock in the liver that responds to feeding/fasting cycles. Adipose tissue is also critical for metabolism and adipocytes have circadian clocks. Yet, the role of the circadian clock in adipocytes is poorly understood. Here we describe our studies that revealed components of the circadian clock in primary adipocyte precursor cells (APCs) in mice. We made the surprising discovery of a particularly prominent role for the circadian gene Period 3 (Per3) in the APC clock. Furthermore, we elucidated that Per3 directly regulates an output pathway of the APC clock to modulate the expression of the Kruppel-like factor 15 (Klf15) gene. Finally, we discovered that this clock-Klf15 pathway regulates adipogenesis in APCs. These finding have important implications for our understanding of adipose tissue biology and metabolism and, we speculate, will generate opportunities to develop novel therapeutic strategies based on the context-specific features of the circadian clock in APCs.

Obesity is a metabolic disease characterized by excessive fat storage, and the adipogenic differentiation of adipose-derived stromal cells (ADSCs) is closely linked to its occurrence. Growth differentiation factor 11 (GDF11), a well-known molecule in the field of anti-aging, also has great potential in regulating stem cell differentiation. In this study, we found that GDF11 inhibited adipogenic differentiation of human ADSCs in vitro by activating the WNT/β-catenin and SMAD2/3 pathways while inhibiting the AKT pathway. Moreover, the transcription factor Kruppel-like factor 15 (KLF15) was discovered to be an important downstream factor for GDF11 in inhibiting adipogenesis via the WNT/β-catenin pathway. Furthermore, AlphaFold2 structure prediction and inhibitor-blocking experiments revealed that ALK5 is a functional receptor of GDF11. Collectively, we demonstrated that GDF11 is a potential target for inhibiting adipogenic differentiation and combating obesity.

Membrane associated ubiquitin ligase MARCH2 majorly involves in inflammation response and protein trafficking. However, its comprehensive role in hepatocellular carcinoma (HCC) is largely unknown. Firstly, multiple bioinformatic analyses were applied to determine MARCH2 mRNA level, its expression comparison in diverse molecular and immune subtypes, and diagnostic value in HCC. Subsequently, RNA-seq, real-time quantitative PCR, immunohistochemistry and cell proliferation assay are used to explore the epithelial–mesenchymal transition (EMT) and proliferation by gene-silencing or overexpressing in cultured HCC cells or in vivo xenograft. Moreover, dual luciferase reporter assay and immunoblotting are delved into verify the transcription factor that activating MARCH2 promoter. Multiple bioinformatic analyses demonstrate that MARCH2 is upregulated in multiple cancer types and exhibits startling diagnostic value as well as distinct molecular and immune subtypes in HCC. RNA-seq analysis reveals MARCH2 may promote EMT, cell proliferation and migration in HepG2 cells. Furthermore, overexpression of MARCH2 triggers EMT and significantly enhances HCC cell migration, proliferation and colony formation in a ligase activity-dependent manner. Additionally, above observations are validated in the HepG2 mice xenografts. For up-stream mechanism, transcription factor KLF15 is highly expressed in HCC and activates MARCH2 expression. KLF15 activated MARCH2 triggers EMT and serves as a fascinating biomarker for precise diagnosis of HCC. Consequently, MARCH2 emerges as a promising candidate for target therapy in cancer management. • Ubiquitin ligase MARCH2 triggers migration, proliferation and epithelial–mesenchymal transition in HCC cell. • MARCH2 acts as a molecular biomarker for precise diagnosis in HCC. • Transcription factor KLF15 activates MARCH2 expression. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) is a common and serious disease with high morbidity and mortality, and its pathophysiological mechanisms are not fully understood. Increasing evidence suggests an important role of ferroptosis in AKI. Krüppel-like factor 15 (KLF15) is a transcription factor involved in several metabolic diseases, but its role in AKI and ferroptosis remains unclear. In this study, we explored the potential role of KLF15 using a folic acid-induced AKI model. Our study showed that KLF15 expression was reduced in kidney tissues of AKI mice, and KLF15 knockout exacerbated folic acid-induced ferroptosis and kidney injury. In vitro studies revealed that the ferroptosis inducer erastin significantly suppressed KLF15 expression in human tubular epithelial cells. Notably, the overexpression of KLF15 attenuated ferroptosis, as evidenced by a decrease in the lipid peroxidation marker of malondialdehyde and the upregulation of glutathione peroxidase 4 (GPX4), while KLF15 knockdown with shRNA exerted the opposite effect. Mechanistically, KLF15 stabilized the protein of nuclear factor erythroid 2-related factor 2 (NRF2) and subsequently increased the GPX4 level. Collectively, KLF15 plays an important role in the modulation of ferroptosis in AKI and may be a potential therapeutic target for treating AKI.

Abstract Background Recently, overwhelming evidence supports that long noncoding RNAs (lncRNAs) play crucial roles in the occurrence and progression of tumors. However, the role and mechanism of lncRNA TFAP2A-AS1 in human gastric cancer (GC) remains unclear. Thus, the biological role and regulatory mechanisms of TFAP2A-AS1 in GC were explored. Methods Quantitative real-time PCR (qPCR) was applied to detect gene expression. Western blot was used to measure protein expression. Cell proliferation and migration were determined by functional assays. Fluorescence in situ hybridization (FISH) assays were performed to determine the subcellular distribution of TFAP2A-AS1 in GC. Mechanism investigations were conducted to explore the downstream genes of TFAP2A-AS1 and the upstream transcription factor of TFAP2A-AS1 in GC cells. Results TFAP2A-AS1 inhibits the proliferation and migration of GC cells. In the downstream regulation mechanism, miR-3657 was verified as the downstream gene of TFAP2A-AS1 and NISCH as the target of miR-3657. NISCH also suppresses cell proliferation and migration in GC. In the upstream regulation mechanism, transcription factor KLF15 positively mediates TFAP2A-AS1 to suppress GC cell proliferation and migration. Conclusion KLF15-mediated TFAP2A-AS1 hampers cell proliferation and migration in GC via miR-3657/NISCH axis.

Abstract Background Obesity-induced elevated serum free fatty acids (FFAs) levels result in the occurrence of type 2 diabetes mellitus (T2DM). However, the molecular mechanism remains largely enigmatic. This study was to explore the effect and mechanism of KLF15 on FFAs-induced abnormal glucose metabolism. Methods Levels of TG, TC, HDL-C, LDL-C, and glucose were measured by different assay kits. qRT-PCR and Western Blot were used to detect the levels of GPR120, GPR40, phosphorylation of p38 MAPK, KLF15, and downstream factors. Results KLF15 was decreased in visceral adipose tissue of obesity subjects and high-fat diet (HFD) mice. In HFD mice, GPR120 antagonist significantly promoted KLF15 protein expression level and phosphorylation of p38 MAPK, meanwhile reduced the blood glucose levels. While, blocking GPR40 inhibited the KLF15 expression. In 3T3-L1 adipocytes, 1500 μM PA inhibited KLF15 through a GPR120/P-p38 MAPK signal pathway, and 750 μM OA inhibited KLF15 mainly through GPR120 while not dependent on P-p38 MAPK, ultimately resulting in abnormal glucose metabolism. Unfortunately, GPR40 didn’t contribute to PA or OA-induced KLF15 reduction. Conclusions Both PA and OA inhibit KLF15 expression through GPR120, leading to abnormal glucose metabolism in adipocytes. Notably, the inhibition of KLF15 expression by PA depends on phosphorylation of p38 MAPK.

Background: Excessive abdominal fat deposition in commercial broilers presents an obstacle to profitable meat quality, feed utilization, and reproduction. Abdominal fat deposition depends on the proliferation of preadipocytes and their maturation into adipocytes, which involves a cascade of regulatory molecules. Accumulating evidence has shown that microRNAs (miRNAs) serve as post-transcriptional regulators of adipogenic differentiation in mammals. However, the miRNA-mediated molecular mechanisms underlying abdominal fat deposition in chickens are still poorly understood. This study aimed to investigate the biological functions and regulatory mechanism of miRNAs in chicken abdominal adipogenesis. Results: We established a chicken model of abdominal adipocyte differentiation and analyzed miRNA and mRNA expression in abdominal adipocytes at different stages of differentiation (0, 12, 48, 72, and 120 h). A total of 217 differentially expressed miRNAs (DE-miRNAs) and 3520 differentially expressed genes were identified. Target prediction of DE-miRNAs and functional enrichment analysis revealed that the differentially expressed targets were significantly enriched in lipid metabolism-related signaling pathways, including the PPAR signaling and MAPK signaling pathways. A candidate miRNA, gga-miR-106-5p, exhibited decreased expression during the proliferation and differentiation of abdominal preadipocytes and was downregulated in the abdominal adipose tissues of fat chickens compared to that of lean chickens. gga-miR-106-5p was found to inhibit the proliferation and adipogenic differentiation of chicken abdominal preadipocytes. A dual-luciferase reporter assay suggested that the KLF15 gene, which encodes a transcriptional factor, is a direct target of gga-miR-106-5p. gga-miR-106-5p suppressed the post-transcriptional activity of KLF15, which is an activator of abdominal preadipocyte proliferation and differentiation, as determined with gain- and loss-of-function experiments. Conclusions: gga-miR-106-5p functions as an inhibitor of abdominal adipogenesis by targeting the KLF15 gene in chickens. These findings not only improve our understanding of the specific functions of miRNAs in avian adipogenesis but also provide potential targets for the genetic improvement of excessive abdominal fat deposition in poultry. [ABSTRACT FROM AUTHOR]

The generation of new adipocytes from precursor cells (adipogenesis) has implications for systemic metabolism and is a commonly used model for studying the process of cell differentiation in vitro. Previous studies from us and others suggested that the peripheral circadian clock can influence adipogenesis in vitro, but the mechanisms driving this activity and the relevance for adipogenesis in vivo are unknown. Here we reveal that mouse adipocyte precursor cells (APCs) contain a circadian clock that oscillates in vivo. We expose context-specific features of the clock in APCs: expression of the canonical core clock component Per1 does not significantly oscillate, whereas the lesser-understood paralog Per3 has a prominent rhythm. We discovered that deletion of Per3 promotes adipogenesis in vivo by a clock output pathway in which PER3 and BMAL1 directly regulate Klf15 expression. These findings demonstrate that Per3 has a major role in the APC clock and regulates adipogenesis in vivo.

Renal unilateral ischemia-reperfusion injury (UIRI) constitutes a significant global health challenge, with poor recovery leading to chronic kidney disease and subsequent renal fibrosis. Extracellular vesicles (EVs) present substantial potential benefits for renal diseases. However, the limited yield and efficacy of EVs produced through traditional methodologies (2D-EVs) severely restrict their widespread application. Moreover, the efficient and effective strategies for using EVs in UIRI treatment and their mechanisms remain largely unexplored. In this study, we propose an innovative approach by integrating bioprinted mesenchymal stem cell microfiber extracellular vesicles production technology (3D-EVs) with a tail vein injection method, introducing a novel treatment strategy for UIRI. Our comparison of the biological functions of 2D-EVs and 3D-EVs, both in vitro and in vivo, reveals that 3D-EVs significantly outperform 2D-EVs. Specifically, in vitro, 3D-EVs demonstrate a superior capacity to enhance the proliferation and migration of NRK-52E cells and mitigate hypoxia/reoxygenation (H/R)-induced injuries by reducing epithelial-mesenchymal transformation, extracellular matrix deposition, and ferroptosis. In vivo, 3D-EVs exhibit enhanced therapeutic effects, as evidenced by improved renal function and decreased collagen deposition in UIRI mouse kidneys. We further elucidate the mechanism by which 3D-EVs derived from KLF15 ameliorate UIRI-induced tubular epithelial cells (TECs) ferroptosis through the modulation of SLC7A11 and GPX4 expression. Our findings suggest that bioprinted mesenchymal stem cells microfiber-derived EVs significantly ameliorate renal UIRI, opening new avenues for effective and efficient EV-based therapies in UIRI treatment., Competing Interests: The authors declare the following personal relationships which may be considered as potential competing interests: Yi Zhang is currently employed by Huaqing Zhimei (Shenzhen) Biotechnology Co., Ltd., (© 2024 The Authors.)

Pathological myocardial hypertrophy is a common early clinical manifestation of heart failure, with noncoding RNAs exerting regulatory influence. However, the molecular function of circular RNAs (circRNAs) in the progression from cardiac hypertrophy to heart failure remains unclear. To uncover functional circRNAs and identify the core circRNA signaling pathway in heart failure, we construct a global triple network (microRNA, circRNA, and mRNA) based on the competitive endogenous RNA (ceRNA) theory. We observe that cardiac hypertrophy-related circRNA (circRNA CHRC), within the ceRNA network, is down-regulated in both transverse aortic constriction mice and Ang-II--treated primary mouse cardiomyocytes. Silencing circRNA CHRC increases cross-sectional cell area, atrial natriuretic peptide, and β-myosin heavy chain levels in primary mouse cardiomyocytes. Further screening shows that circRNA CHRC targets the miR-431-5p/KLF15 axis implicated in heart failure progression in vivo and in vitro. Immunoprecipitation with anti-Ago2-RNA confirms the interaction between circRNA CHRC and miR-431-5p, while miR-431-5p mimics reverse Klf15 activation caused by circRNA CHRC overexpression. In summary, circRNA CHRC attenuates cardiac hypertrophy via sponging miR-431-5p to maintain the normal level of Klf15 expression., Competing Interests: Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.)

Abstract Background A therapeutic approach for the treatment of glucocorticoid‐induced skeletal muscle atrophy should be based on the knowledge of the molecular mechanisms determining the unbalance between anabolic and catabolic processes and how to re‐establish this balance. Here, we investigated whether the obestatin/GPR39 system, an autocrine signalling system acting on myogenesis and with anabolic effects on the skeletal muscle, could protect against chronic glucocorticoid‐induced muscle atrophy. Methods In this study, we used an in vivo model of muscle atrophy induced by the synthetic glucocorticoid dexamethasone to examine the liaison molecules that define the interaction between the glucocorticoid receptor and the obestatin/GPR39 systems. The findings were extended to in vitro effects on human atrophy using human KM155C25 myotubes. Results KLF15 and FoxO transcription factors were identified as direct targets of obestatin signalling in the control of proteostasis in skeletal muscle. The KLF15‐triggered gene expression program, including atrogenes and FoxOs, was regulated via KLF15 ubiquitination by the E3 ubiquitin ligase NEDD4. Additionally, a specific pattern of FoxO post‐translational modification, including FoxO4 phosphorylation by Akt pathway, was critical in the regulation of the ubiquitin–proteasome system. The functional cooperativity between Akt and NEDD4 in the regulation of FoxO and KLF15 provides integrated cues to counteract muscle proteostasis and re‐establish protein synthesis. Conclusions The effective control of FoxO activity in response to glucocorticoid is critical to counteract muscle‐related pathologies. These results highlight the potential of the obestatin/GPR39 system to fine‐tune the effects of glucocorticoids on skeletal muscle wasting.

Recent studies have linked branched-chain amino acid (BCAA) with numerous metabolic diseases. However, the molecular basis of BCAA's roles in metabolic regulation remains to be established. KLF15 (Krüppel-like factor 15) is a transcription factor and master regulator of glycemic, lipid, and amino acids metabolism. In the present study, we found high concentrations of BCAA suppressed KLF15 expression while BCAA starvation induced KLF15 expression, suggesting KLF15 expression is negatively controlled by BCAA.Interestingly, BCAA starvation induced PI3K-AKT signaling. KLF15 induction by BCAA starvation was blocked by PI3K and AKT inhibitors, indicating the activation of PI3K-AKT signaling pathway mediated the KLF15 induction. BCAA regulated KLF15 expression at transcriptional level but not post-transcriptional level. However, BCAA starvation failed to increase the KLF15-promoter-driven luciferase expression, suggesting KLF15 promoter activity was not directly controlled by BCAA. Finally, fasting reduced BCAA abundance in mice and KLF15 expression was dramatically induced in muscle and white adipose tissue, but not in liver. Together, these data demonstrated BCAA negatively regulated KLF15 expression, suggesting a novel molecular mechanism underlying BCAA's multiple functions in metabolic regulation.

Spinal Muscular Atrophy (SMA) and Amyotrophic Lateral Sclerosis (ALS) are neurodegenerative diseases which are characterized by the loss of motoneurons within the central nervous system. SMA is a monogenic disease caused by reduced levels of the Survival of motoneuron protein, whereas ALS is a multi-genic disease with over 50 identified disease-causing genes and involvement of environmental risk factors. Although these diseases have different causes, they partially share identical phenotypes and pathomechanisms. To analyze and identify functional connections and to get a global overview of altered pathways in both diseases, protein network analyses are commonly used. Here, we used an in silico tool to test for functional associations between proteins that are involved in actin cytoskeleton dynamics, fatty acid metabolism, skeletal muscle metabolism, stress granule dynamics as well as SMA or ALS risk factors, respectively. In network biology, interactions are represented by edges which connect proteins (nodes). Our approach showed that only a few edges are necessary to present a complex protein network of different biological processes. Moreover, Superoxide dismutase 1, which is mutated in ALS, and the actin-binding protein profilin1 play a central role in the connectivity of the aforementioned pathways. Our network indicates functional links between altered processes that are described in either ALS or SMA. These links may not have been considered in the past but represent putative targets to restore altered processes and reveal overlapping pathomechanisms in both diseases. [ABSTRACT FROM AUTHOR]

Introduction: Papillary thyroid cancer (PTC) is the predominant histological type of thyroid cancer, accounting for 80% of thyroid cancers. MiR-181a is a novel microRNA that is usually upregulated in multiple cancers. This study aims to explore the role and underlying mechanism of miR-181a in PTC. Methods: CCK8 and Transwell assays were performed to evaluate cell viability and migration. The mRNA level of miR-181a and KLF15 was calculated by qRT-PCR. The protein level of E-Cadherin, N-Cadherin and GAPDH was evaluated by western blot. Dual luciferase assay was conducted to validate that miR-181a directly targeting the 3′-UTR of KLF15 mRNA in TPC-1 cells. Results: We observed that miR-181a was overexpressed and KLF15 was low expressed in PTC tissues and cell lines. Upregulation of miR-181a or downregulation of KLF15 predicted poor outcomes in PTC patients. MiR-181a improved cell growth of PTC, migration and epithelial–mesenchymal transition (EMT) in TPC-1 cells. KLF15 was a target gene of miR-181a and its expression was mediated by miR-181a. KLF15 partially reversed the facilitating effect of miR-181a on cell proliferation and migration in TPC-1 cells. Conclusion: We discovered that miR-181a served as an oncogene downregulating KLF15, thereby inhibiting cell proliferation, migration and the EMT. These findings demonstrate that miR-181a plays a significant role in PTC progression and could be a therapeutic target for PTC. [ABSTRACT FROM AUTHOR]

The Drosophila lymph gland is the larval hematopoietic organ and is aligned along the anterior part of the cardiovascular system, composed of cardiac cells, that form the cardiac tube and its associated pericardial cells or nephrocytes. By the end of embryogenesis the lymph gland is composed of a single pair of lobes. Two additional pairs of posterior lobes develop during larval development to contribute to the mature lymph gland. In this study we describe the ontogeny of lymph gland posterior lobes during larval development and identify the genetic basis of the process. By lineage tracing we show here that each posterior lobe originates from three embryonic pericardial cells, thus establishing a bivalent blood cell/nephrocyte potential for a subset of embryonic pericardial cells. The posterior lobes of L3 larvae posterior lobes are composed of heterogeneous blood progenitors and their diversity is progressively built during larval development. We further establish that in larvae, homeotic genes and the transcription factor Klf15 regulate the choice between blood cell and nephrocyte fates. Our data underline the sequential production of blood cell progenitors during larval development.

Amyotrophic Lateral Sclerosis (ALS) is a currently incurable disease that causes progressive motor neuron loss, paralysis and death. Skeletal muscle pathology occurs early during the course of ALS. It is characterized by impaired mitochondrial biogenesis, metabolic dysfunction and deterioration of the neuromuscular junction (NMJ), the synapse through which motor neurons communicate with muscles. Therefore, a better understanding of the molecules that underlie this pathology may lead to therapies that slow motor neuron loss and delay ALS progression. Kruppel Like Factor 15 (KLF15) has been identified as a transcription factor that activates alternative metabolic pathways and NMJ maintenance factors, including Fibroblast Growth Factor Binding Protein 1 (FGFBP1), in skeletal myocytes. In this capacity, KLF15 has been shown to play a protective role in Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA), however its role in ALS has not been evaluated. Here, we examined whether muscle-specific KLF15 overexpression promotes the health of skeletal muscles and NMJs in the SOD1G93A ALS mouse model. We show that muscle-specific KLF15 overexpression did not elicit a significant beneficial effect on skeletal muscle atrophy, NMJ health, motor function, or survival in SOD1G93A ALS mice. Our findings suggest that, unlike in mouse models of DMD and SMA, KLF15 overexpression has a minimal impact on ALS disease progression in SOD1G93A mice.

Cardiomyocyte apoptosis is a characteristic of a variety of cardiac diseases, including myocardial infarction (MI). Krüppel-like factor 15 (KLF15) is a transcription factor of Krüppel family that plays an important part in cardiovascular diseases. However, the function and the underlying mechanism of KLF15 in MI remain unknown. The expression of KLF15 was downregulated both in ischemic myocardium of MI mice model and hypoxia-treated neonatal rat ventricular myocytes (NRVCs). KLF15 overexpression mediated by adeno-associated virus significantly abrogated the ischemia-induced cardiac dysfunction, increased the survival rate, and reduced infarct size after MI. Meanwhile, KLF15 overexpression dramatically reduced the myocardial apoptosis, regulated apoptosis-related genes, such as Bcl2 and Bax, diminished the activities of caspase-9/3, and inactivated p38/MAPK signaling in the border zone. Similar results were observed in NRVCs exposed to hypoxia. We demonstrated for the first time that KLF15 overexpression could reduce cardiomyocyte apoptosis and improve cardiac dysfunction in MI mice at least partially by inhibiting p38/MAPK signaling pathway. [ABSTRACT FROM AUTHOR]

Background: Obesity-induced elevated serum free fatty acids (FFAs) levels result in the occurrence of type 2 diabetes mellitus (T2DM). However, the molecular mechanism remains largely enigmatic. This study was to explore the effect and mechanism of KLF15 on FFAs-induced abnormal glucose metabolism. Methods: Levels of TG, TC, HDL-C, LDL-C, and glucose were measured by different assay kits. qRT-PCR and Western Blot were used to detect the levels of GPR120, GPR40, phosphorylation of p38 MAPK, KLF15, and downstream factors. Results: KLF15 was decreased in visceral adipose tissue of obesity subjects and high-fat diet (HFD) mice. In HFD mice, GPR120 antagonist significantly promoted KLF15 protein expression level and phosphorylation of p38 MAPK, meanwhile reduced the blood glucose levels. While, blocking GPR40 inhibited the KLF15 expression. In 3T3-L1 adipocytes, 1500 μM PA inhibited KLF15 through a GPR120/P-p38 MAPK signal pathway, and 750 μM OA inhibited KLF15 mainly through GPR120 while not dependent on P-p38 MAPK, ultimately resulting in abnormal glucose metabolism. Unfortunately, GPR40 didn't contribute to PA or OA-induced KLF15 reduction. Conclusions: Both PA and OA inhibit KLF15 expression through GPR120, leading to abnormal glucose metabolism in adipocytes. Notably, the inhibition of KLF15 expression by PA depends on phosphorylation of p38 MAPK. [ABSTRACT FROM AUTHOR]

Background: Recently, overwhelming evidence supports that long noncoding RNAs (lncRNAs) play crucial roles in the occurrence and progression of tumors. However, the role and mechanism of lncRNA TFAP2A-AS1 in human gastric cancer (GC) remains unclear. Thus, the biological role and regulatory mechanisms of TFAP2A-AS1 in GC were explored. Methods: Quantitative real-time PCR (qPCR) was applied to detect gene expression. Western blot was used to measure protein expression. Cell proliferation and migration were determined by functional assays. Fluorescence in situ hybridization (FISH) assays were performed to determine the subcellular distribution of TFAP2A-AS1 in GC. Mechanism investigations were conducted to explore the downstream genes of TFAP2A-AS1 and the upstream transcription factor of TFAP2A-AS1 in GC cells. Results: TFAP2A-AS1 inhibits the proliferation and migration of GC cells. In the downstream regulation mechanism, miR-3657 was verified as the downstream gene of TFAP2A-AS1 and NISCH as the target of miR-3657. NISCH also suppresses cell proliferation and migration in GC. In the upstream regulation mechanism, transcription factor KLF15 positively mediates TFAP2A-AS1 to suppress GC cell proliferation and migration. Conclusion: KLF15-mediated TFAP2A-AS1 hampers cell proliferation and migration in GC via miR-3657/NISCH axis. [ABSTRACT FROM AUTHOR]

Abstract Background Long non-coding RNAs (lncRNAs) are novel regulatory molecules in breast cancer development. LncRNA LUCAT1 is a potential tumor promoter in human cancers. In this study, we aimed to explore the role of LUCAT1 in human breast cancer tissues and cells. Methods A total of 31 breast cancer patients who underwent tumor resection, but without chemo- or radiotherapy or acute lung/heart/kidney diseases, provided tumor and adjacent normal tissues. Bioinformatic analysis, qRT-PCR, and luciferase reporter assay were carried out during the study. Results qRT-PCR analysis indicated that, compared with the adjacent tissues and MCF-10A normal breast epithelial cells, LUCAT1 was markedly up-regulated in the breast cancer tissues and five BC cell lines, including MDA-MB-231, MDA-MB-468, MDA-MB-435, SKBR3, and MCF-7. The knockdown of LUCAT1, through the transfection of small interfering RNA (siRNA) specific to LUCAT1, resulted in inhibition of proliferation in breast cancer cells. The expression levels of miR-181a-5p were decreased in the breast cancer tissues and five BC cell lines. Bioinformatic analysis and luciferase reporter assay suggested the interaction between miR-181a-5p and LUCAT1. In addition, the effects of LUCAT1 on promoting cell proliferation were attenuated by overexpression of miR-181a-5p through the transfection of miR-181a-5p mimic. Moreover, bioinformatics and luciferase reporter assay confirmed that miR-181a-5p targeted the 3′-UTR region of KLF6 and KLF15 mRNA, which were two tumor suppressor genes. LUCAT1/miR-181a-5p axis regulated the expression of KLF6 and KLF15 both in vitro and in vivo. Conclusions Our data indicate that LUCAT1/miR-181a-5p axis can serve as a novel therapeutic target in breast cancer.

Thoracic aortic dissection (TAD) is a highly dangerous cardiovascular disorder caused by weakening of the aortic wall, resulting in a sudden tear of the internal face. Progressive loss of the contractile apparatus in vascular smooth muscle cells (VSMCs) is a major event in TAD. Exploring the endogenous regulators essential for the contractile phenotype of VSMCs may aid the development of strategies to prevent TAD. Krüppel-like factor 15 (KLF15) overexpression was reported to inhibit TAD formation; however, the mechanisms by which KLF15 prevents TAD formation and whether KLF15 regulates the contractile phenotype of VSMCs in TAD are not well understood. Therefore, we investigated these unknown aspects of KLF15 function. We found that KLF15 expression was reduced in human TAD samples and β-aminopropionitrile monofumarate-induced TAD mouse model. Klf15KO mice are susceptible to both β-aminopropionitrile monofumarate- and angiotensin II-induced TAD. KLF15 deficiency results in reduced VSMC contractility and exacerbated vascular inflammation and extracellular matrix degradation. Mechanistically, KLF15 interacts with myocardin-related transcription factor B (MRTFB), a potent serum response factor coactivator that drives contractile gene expression. KLF15 silencing represses the MRTFB-induced activation of contractile genes in VSMCs. Thus, KLF15 cooperates with MRTFB to promote the expression of contractile genes in VSMCs, and its dysfunction may exacerbate TAD. These findings indicate that KLF15 may be a novel therapeutic target for the treatment of TAD., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The impaired endometrial receptivity is a major factor contributing to infertility in patients with endometriosis (EM), but the underlying mechanism remains unclear. Our study aimed to investigate the role of Kruppel-like factor 15 (KLF15) in endometrial receptivity and its regulation in EM. We observed a significant decrease in KLF15 expression in the mid-secretory epithelial endometrial cells of EM patients compared to normal females without EM. To confirm the role of KLF15 in endometrial receptivity, we found a significantly reduced KLF15 expression and a significant decrease in embryo implantation number in the rat model via uterine horn infection with siRNA. This highlights the importance of KLF15 as a regulator receptivity. Furthermore, through ChIP-qPCR, we discovered that the progesterone receptor (PR) directly binds to KLF15 promoter regions, indicating that progesterone resistance may mediate the decrease in KLF15 expression in EM patients. Additionally, we found that the mid-secretory endometrium of EM patients exhibited impaired epithelial-mesenchymal transition (EMT). Knockdown of KLF15 upregulated E-cadherin and downregulated vimentin expression, leading to inhibited invasiveness and migration of Ishikawa cells. Overexpression KLF15 promotes EMT, invasiveness, and migration ability, and increases the attachment rate of JAR cells to Ishikawa cells. Through RNA-seq analysis, we identified TWIST2 as a downstream gene of KLF15. We confirmed that KLF15 directly binds to the promoter region of TWIST2 via ChIP-qPCR, promoting epithelial cell EMT during the establishment of endometrial receptivity. Our study reveals the involvement of KLF15 in the regulation of endometrial receptivity and its downstream effects on EMT. These findings provide valuable insights into potential therapeutic approaches for treating non-receptive endometrium in patients with EM.

Objective: To explore the mechanism of KLF15 on the biological activity and autophagy of gastric cancer cells based on the PI3K/Akt/mTOR signaling pathway., Material and Methods: The gastric cancer AGS cells were divided into the Con group, pcDNANC group, pcDNA-KLF15 group, LY294002 group and IGF-1 group. RT-PCR was used to detect the expression of KLF15 in human gastric mucosal cells and gastric cancer cells; MTT method to detect cell proliferation; Transwell method to detect cell invasion; flow cytometry to detect cell apoptosis; Western blotting to detect PI3K, Akt, mTOR in cells, LC3, Beclin1, p62 protein expression.P<0.05 was used to indicate statistical significance., Results: Compared with the human gastric mucosal cell line GES-1 cells, the expression of KLF15 in human gastric cancer cell lines MKN-28, MFC, SCG-7901 and AGS cells was significantly decreased, And the expression of KLF15 in AGS cells, was the lowest (P=0.006). Compared with the Con group, The expression of KLF15 in the cells of the PCDNA-KLF15 group was significantly increased (P=0.018); There was no significant difference in the expression of KLF15 between the Con group and the PCDNA-NC group (P=0.225). Compared with the Con group, the proliferation and invasion abilities of the cells in the pcDNA-KLF15 group were significantly reduced, And the apoptosis ability was significantly increased (P=0.019). The ratio of LC3II/LC31 and the expression of Beclin1 Protein in the control group were significantly higher than those in the Con group (P=0.017)., Conclusion: Overexpression of KLF15 can inhibit the proliferation and invasion of Gastric cancer cells and promote cell apoptosis and autophagy, and its mechanism may be related to the regulation of the PI3K/Akt/mTOR signaling pathway., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

OBJECTIVE: This study aims to explore the biological roles of long non-coding RNA (lncRNA) ZNF281 and KLF15 in regulating cervical carcinoma progression. PATIENTS AND METHODS: Differential expressions of ZNF281 in 58 collected cervical carcinoma and normal tissues were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between ZNF281 and clinicopathologic characteristics in cervical carcinoma patients was analyzed. By generating ZNF281 knockdown model in HeLa and Si- Ha cells through the transfection of shZNF281, migratory ability changes were examined via transwell and wound healing assay. The role of ZNF281 in in vivo tumorgenicity of cervical carcinoma was examined by implanting xenografted cancers in nude mice. The downstream target of ZNF281 and their interaction were assessed by bioinformatics tool and Dual-Luciferase reporter assay, respectively. Finally, co-regulations of ZNF281 and KLF15 on cervical carcinoma progression were elucidated. RESULTS: ZNF281 was upregulated in cervical carcinoma tissues and cell lines. It was correlated to TNM staging, and incidences of lymphatic metastasis and distant metastasis in cervical carcinoma patients, while it was unrelated to age and tumor size. The knockdown of ZNF281 effectively attenuated migratory ability in HeLa and SiHa cells. Besides, knockdown of ZNF281 also reduced tumorigenicity of cervical carcinoma in nude mice. KLF15 was the downstream gene binding ZNF281, and they were negatively correlated to each other in cervical carcinoma tissues. Notably, KLF15 was responsible for ZNF281-induced regulation on cervical carcinoma migration. CONCLUSIONS: LncRNA ZNF281 is upregulated in cervical carcinoma samples, and it is correlated to lymphatic metastasis, distant metastasis, and poor prognosis in cervical carcinoma patients. By targeting KLF15, ZNF281 triggers migratory potential in cervical carcinoma. We believed that ZNF281 is a promising biomarker for cervical carcinoma. [ABSTRACT FROM AUTHOR]

Mesangial cell (MC) proliferation is a key pathological feature in a number of common human renal diseases, including mesangial proliferative nephritis and diabetic nephropathies. Knowledge of MC responses to pathological stimuli is crucial to the understanding of these disease processes. We previously determined that Krϋppel‐like factor 15 (KLF15), a kidney‐enriched zinc‐finger transcription factor, was required for inhibition of MC proliferation. In the present study, we investigated the direct target gene and the underlying mechanism by which KLF15 regulated mesangial proliferation. First, we screened small ubiquitin‐related modifier 1 (SUMO1) as the direct transcriptional target of KLF15 and validated this finding with ChIP‐PCR and luciferase assays. Furthermore, we demonstrated that overexpressing KLF15 or SUMO1 enhanced the stability of P53, which blocked the cell cycle of human renal MCs (HRMCs) and therefore abolished cell proliferation. Conversely, knockdown of SUMO1 in HRMCs, even those overexpressed with KLF15, could not inhibit HRMC proliferation rates and increase SUMOylation of P53. Finally, the results showed that the levels of SUMOylated P53 in the kidney cortices of anti‐Thy 1 model rats were decreased during proliferation periods. These findings reveal the critical mechanism by which KLF15 targets SUMO1 to mediate the proliferation of MCs. [ABSTRACT FROM AUTHOR]

Background: A therapeutic approach for the treatment of glucocorticoid‐induced skeletal muscle atrophy should be based on the knowledge of the molecular mechanisms determining the unbalance between anabolic and catabolic processes and how to re‐establish this balance. Here, we investigated whether the obestatin/GPR39 system, an autocrine signalling system acting on myogenesis and with anabolic effects on the skeletal muscle, could protect against chronic glucocorticoid‐induced muscle atrophy. Methods: In this study, we used an in vivo model of muscle atrophy induced by the synthetic glucocorticoid dexamethasone to examine the liaison molecules that define the interaction between the glucocorticoid receptor and the obestatin/GPR39 systems. The findings were extended to in vitro effects on human atrophy using human KM155C25 myotubes. Results: KLF15 and FoxO transcription factors were identified as direct targets of obestatin signalling in the control of proteostasis in skeletal muscle. The KLF15‐triggered gene expression program, including atrogenes and FoxOs, was regulated via KLF15 ubiquitination by the E3 ubiquitin ligase NEDD4. Additionally, a specific pattern of FoxO post‐translational modification, including FoxO4 phosphorylation by Akt pathway, was critical in the regulation of the ubiquitin–proteasome system. The functional cooperativity between Akt and NEDD4 in the regulation of FoxO and KLF15 provides integrated cues to counteract muscle proteostasis and re‐establish protein synthesis. Conclusions: The effective control of FoxO activity in response to glucocorticoid is critical to counteract muscle‐related pathologies. These results highlight the potential of the obestatin/GPR39 system to fine‐tune the effects of glucocorticoids on skeletal muscle wasting. [ABSTRACT FROM AUTHOR]

Jing Jiang,1 Yimeng Xia,2 Yi Liang,1 Meiling Yang,1 Wen Zeng,1 Xiaocong Zeng3 1Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, People’s Republic of China; 2Department of Anesthesiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, People’s Republic of China; 3Department of Cardiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, People’s Republic of China Purpose: miR-190a-5p expression alters dynamically in response to hypoxia. However, the role of miR-190a-5p expression in hypoxia-induced pulmonary hypertension (PH) remains unclear. We sought to correlate the miR-190a-5p expression levels with the severity, diagnosis, and prognosis of PH in relation to chronic obstructive pulmonary disease (COPD-PH). Additionally, we evaluated the effect of miR-190a-5p through in vitro experiments on human pulmonary endothelial cells (HPECs) that were exposed to hypoxia and in vivo experiments using an animal model of hypoxia-induced PH.Methods: Circulating miR-190a-5p levels were measured from 73 patients with PH and 32 healthy controls through quantitative real-time PCR. The levels of miR-190a-5p and the expression of Krüppel-like factor 15 (KLF15) were analyzed in HPECs that were exposed to hypoxia, and the effects of antagomir-190a-5p in mice with chronic hypoxia-induced PH were tested. Target gene analysis was performed by Western blot and luciferase assay.Results: The miR-190a-5p level was significantly higher in patients with COPD-PH than in the healthy controls. Higher miR-190a-5p levels were associated with a greater severity of COPD-PH. In vitro experiments on HPECs showed that exposure to hypoxia increased the miR-190a-5p levels significantly. KLF15 was validated as a target of miR-190a-5p. Transfection with miR-190a-5p mimicked inhibition of KLF15 expression in HPECs. In the mouse model of PH, antagomir-190a-5p reduced right ventricular systolic pressure and enhanced the KLF15 expression levels in lung tissue.Conclusion: miR-190a-5p regulates hypoxia-induced PH by targeting KLF15. The circulating levels of miR-190a-5p correlate with the severity of COPD-PH, thereby confirming the diagnostic and prognostic value of this parameter in COPD-PH. Keywords: hypoxia, pulmonary hypertension, COPD, miR-190a-5p, KLF15

Skeletal muscle metabolism is highly adaptive in response to nutritional changes, as occur during food deprivation. Krüppel-like factor 15 (KLF15), as a critical regulator of branched-chain amino acids (BCAAs) metabolism, which plays an important role in energy metabolism. But the role for KLF15 in adaptation and physiology of fish skeletal muscle remains unclear. In this study, we obtained the complete cDNA of Chinese perch (Siniperca chuatsi) KLF15 and investigated its expression in different tissues as well as its expression characteristics during short-term (3 or 7 days) fasting and glucocorticoid (prednisolone) treatment in Chinese perch. Sequence analysis indicated that ScKLF15 showed a highly conservative Zinc finger C2H2 superfamily domain at its C terminal with those of other vertebrates. Tissue specificity analysis showed that ScKLF15 was highly expressed in fast muscle. During the short-term fasting, the expression of KLF15 was significantly increased after 3 days fasting and decreased after 7 days fasting as well as the expression of branched-chain aminotransferase 2 (BCAT2) and the activity of alanine aminotransferase (ALT). Under the prednisolone stimulation, the expression of KLF15 and BCAT2 were significantly increased at 5 days post injection. Furthermore, the activity of ALT and aspartate aminotransferase (AST) showed the same tendency after the injection. Thus, this work revealed that the catabolism of BCAAs was enhanced to maintain the physiological homeostasis in the fish when faced with food deprivation and glucocorticoids stress. More importantly, the study suggested that KLF15 plays a role in adaptive regulation of BCAAs metabolism in skeletal muscle of Chinese perch.

OBJECTIVE: The purpose of this study was to uncover the role of microRNA- 376a-3p (miR-376a-3p) in mediating migratory and invasive capacities of glioma, as well as the underlying mechanism. PATIENTS AND METHODS: MiR-376a-3p levels in 39 collected glioma tissues were detected. After collecting clinical data of included glioma patients, the relationship between miR- 376a-3p level and clinical features of glioma was analyzed. Next, regulatory effects of miR-376a- 3p on proliferative and metastatic capacities of U251 and T98-G cells were assessed. Downstream genes of miR-376a-3p were searched by bioinformatics approach. At last, the involvement of KLF15 in the development of glioma regulated by miR-376a-3p was explored. RESULTS: It was found that miR-376a-3p was lowly expressed in glioma tissues. Low level of miR-376a-3p was linked to high metastasis rate and poor prognosis in glioma. Besides, overexpression of miR-376a-3p suppressed proliferative and metastatic capacities of glioma cells. KLF15, the downstream gene binding miR-376a-3p, was highly expressed in glioma, and displayed a negative correlation to miR-376a-3p. Notably, KLF15 was able to abolish the regulatory effects of miR- 376a-3p on phenotypes of glioma cells. CONCLUSIONS: MiR-376a-3p is related to lymphatic metastasis and distant metastasis of glioma, and alleviates metastasis of glioma by negatively regulating KLF15. [ABSTRACT FROM AUTHOR]

Adaptation to nutrient availability is crucial for survival. Upon nutritional stress, such as during prolonged fasting or cold exposure, organisms need to balance the feeding of tissues and the maintenance of body temperature. The mechanisms that regulate the adaptation of brown adipose tissue (BAT), a key organ for non-shivering thermogenesis, to variations in nutritional state are not known. Here we report that specific deletion of the activin receptor ALK7 in BAT resulted in fasting-induced hypothermia due to exaggerated catabolic activity in brown adipocytes. After overnight fasting, BAT lacking ALK7 showed increased expression of genes responsive to nutrient stress, including the upstream regulator KLF15, aminoacid catabolizing enzymes, notably proline dehydrogenase (POX), and adipose triglyceride lipase (ATGL), as well as markedly reduced lipid droplet size. In agreement with this, ligand stimulation of ALK7 suppressed POX and KLF15 expression in both mouse and human brown adipocytes. Treatment of mutant mice with the glucocorticoid receptor antagonist RU486 restored KLF15 and POX expression levels in mutant BAT, suggesting that loss of BAT ALK7 results in excessive activation of glucocorticoid signaling upon fasting. These results reveal a novel signaling pathway downstream of ALK7 which regulates the adaptation of BAT to nutrient availability by limiting nutrient stress-induced overactivation of catabolic responses in brown adipocytes.

Abstract Background Left ventricular hypertrophy (LVH) increases the risk of death in chronic kidney disease (CKD). The transcription factor Kruppel-like factor 15 (KLF15) is expressed in the heart and regulates cardiac remodelling through inhibition of hypertrophy and fibrosis. It is unknown if KLF15 expression is changed in CKD induced LVH, or whether expression is modulated by blood pressure reduction using angiotensin converting enzyme (ACE) inhibition. Methods CKD was induced in Sprague–Dawley rats by subtotal nephrectomy (STNx), and rats received vehicle (n = 10) or ACE inhibition (ramipril, 1 mg/kg/day, n = 10) for 4 weeks. Control, sham-operated rats (n = 9) received vehicle. Cardiac structure and function and expression of KLF15 were assessed. Results STNx caused impaired kidney function (P

OBJECTIVE: The aim of this study was to explore the regulatory effects of micro ribonucleic acid (miR)-376b-3p on proliferation and apoptosis of non-small cell lung cancer (NSCLC) cells by targeting Kruppel-like factor 15 (KLF15) and its mechanism of action. PATIENTS AND METHODS: The expression of miR-376b-3p in NSCLC and para-carcinoma normal tissues, as well as NSCLC cell lines, was detected via quantitative Polymerase Chain Reaction (qPCR). The effects of miR-548-3p on the proliferation, cycle distribution, and apoptosis of NSCLC cells were detected via colony formation assay, flow cytometry, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, respectively. The interaction between miR-376b-3p and KLF15 was determined using Dual-Luciferase reporter gene assay. In vivo tumorigenic ability of NSCLC cells was studied using nude mouse tumorigenicity assay. Furthermore, the expression of Ki67 in tumor in nude mice was detected via immunohistochemistry. RESULTS: The expression of miR-376b-3p was significantly downregulated in NSCLC tissues when compared with para-carcinoma normal tissues (p<0.05). MiR-376b-3p was lowly expressed in NSCLC cells as well (p<0.05). After overexpression of miR-376b-3p, the proliferation ability of NSCLC cells remarkably declined (p<0.05). The apoptosis rate rose, and cell cycle was arrested in the G1/G0 phase. Dual-Luciferase reporter gene assay confirmed that miR376b-3p could specifically bind to KLF15 3’UTR to regulate the expression activity of KLF15. After overexpression of miR-376b-3p, tumor volume and weight were significantly reduced in tumor-bearing mice (p<0.05). CONCLUSIONS: MiR-376b-3p plays an important role in the occurrence and development of NSCLC, which affects the proliferation and apoptosis of NSCLC cells by targeting KLF15. [ABSTRACT FROM AUTHOR]

Ischemia-reperfusion (I/R) injury is a kind of the tissue damage caused by an abrupt re-supplying tissue with blood after a period of ischemia or hypoxia. It contributes to a wide range of pathological processes including kidney injury, circulatory arrest, and especially cardiovascular disease. However, the underlying pathological mechanism is not fully elucidated. Previously, extensive studies demonstrated that miRNAs participate in the pathogenesis of I/R injury, such as I/R-induced cardiomyocyte apoptosis. Here, we found that miR-137-3p, a mature form of miR-137, was up-regulated in I/R-injured cardiomyocytes of myocardial infarction patients. Deficiency of miR-137-3p partly alleviated the cardiomyocyte apoptosis and oxidative stress induced by hypoxia-reoxygenation (H/R) treatment in H9c2 cells. Also, we provided evidences that miR-137-3p directly targeted the 3' UTR of KLF15 mRNA to down-regulate its expression, and loss function of KLF15 significantly abolished the deleterious effects of ectopic miR-137-3p on cardiomyocytes both in vitro and in vivo. Collectively, these observations highlight a molecular perturbation in the pathogenesis of I/R injury in cardiomyocytes. [ABSTRACT FROM AUTHOR]

Adipose tissue stores energy in the form of triglycerides. The ability to regulate triglyceride synthesis and breakdown based on nutrient status (e.g., fed versus fasted) is critical for physiological homeostasis and dysregulation of this process can contribute to metabolic disease. Whereas much is known about hormonal control of this cycle, transcriptional regulation is not well understood. Here, we show that the transcription factor Kruppel-like factor 15 (KLF15) is critical for the control of adipocyte lipid turnover. Mice lacking Klf15 in adipose tissue (AK15KO) display decreased adiposity and are protected from diet-induced obesity. Mechanistic studies suggest that adipose KLF15 regulates key genes of triglyceride synthesis and inhibits lipolytic action, thereby promoting lipid storage in an insulin-dependent manner. Finally, AK15KO mice demonstrate accelerated lipolysis and altered systemic energetics (e.g., locomotion, ketogenesis) during fasting conditions. Our study identifies adipose KLF15 as an essential regulator of adipocyte lipid metabolism and systemic energy balance.

The generation of new adipocytes from precursor cells (adipogenesis) has implications for systemic metabolism and is a commonly used model for studying the process of cell differentiation in vitro. Previous studies from us and others suggested that the peripheral circadian clock can influence adipogenesis in vitro, but the mechanisms driving this activity and the relevance for adipogenesis in vivo are unknown. Here we reveal that mouse adipocyte precursor cells (APCs) contain a circadian clock that oscillates in vivo. We expose context-specific features of the clock in APCs: expression of the canonical core clock component Per1 does not significantly oscillate, whereas the lesser-understood paralog Per3 has a prominent rhythm. We discovered that deletion of Per3 promotes adipogenesis in vivo by a clock output pathway in which PER3 and BMAL1 directly regulate Klf15 expression. These findings demonstrate that Per3 has a major role in the APC clock and regulates adipogenesis in vivo.

Hematopoietic cell lineages support organismal needs by responding to positional and systemic signals that balance proliferative and differentiation events. Drosophila provides an excellent genetic model to dissect these signals, where the activity of cues in the hemolymph or substrate can be traced to determination and differentiation events of well characterized hemocyte types. Plasmatocytes in third instar larvae increase in number in response to infection and in anticipation of metamorphosis. Here we characterize hemocyte clustering, proliferation and transdifferentiation on the heart or dorsal vessel. Hemocytes accumulate on the inner foldings of the heart basement membrane, where they move with heart contraction, and are in proximity to the heart ostia and pericardial nephrocytes. The numbers of hemocytes vary, but increase transiently before pupariation, and decrease by 4 h before pupa formation. During their accumulation at the heart, plasmatocytes can proliferate and can transdifferentiate into crystal cells. Serrate expressing cells as well as lamellocyte-like, Atilla expressing ensheathing cells are associated with some, but not all hemocyte clusters. Hemocyte aggregation is enhanced by the presence of a heart specific Collagen, Pericardin, but not the associated pericardial cells. The varied and transient number of hemocytes in the pericardial compartment suggests that this is not a hematopoietic hub, but a niche supporting differentiation and rapid dispersal in response to systemic signals. • Clusters of hemocytes transiently collect in the heart ECM hours before pupariation in Drosophila. • In the absence of Pericardin, a Drosophila heart Collagen, this aggregation is greatly reduced. • Hemocyte trans-differentiation is observed in the pericardial aggregates. • Although mitosis is rare, lamellocyte-like ensheathing cells and Serrate expressing cells are observed. • Pericardial aggregation is enhanced and accelerated in response to environmental bacteria. [ABSTRACT FROM AUTHOR]

KLF15 has recently emerged as a central regulator of metabolism. Although its connection to oxidative stress has been suspected, there has not been any study to date that directly demonstrates the molecular link. In this study, we sought to determine the role of KLF15 in cardiac oxidative stress. We found that KLF15 deficiency in the heart is associated with increased oxidative stress. Acute deficiency of KLF15 in neonatal rat ventricular myocytes (NRVMs) leads to the defective clearance of reactive oxygen species (ROS) and an exaggerated cell death following a variety of oxidative stresses. Mechanistically, we found that KLF15 deficiency leads to reduced amounts of the rate-limiting NAD+ salvage enzyme NAMPT and to NAD+ deficiency. The resultant SIRT3-dependent hyperacetylation and the inactivation of mitochondrial antioxidants can be rescued by MnSOD mimetics or NAD+ precursors. Collectively, these findings suggest that KLF15 regulates cardiac ROS clearance through the regulation of NAD+ levels. Our findings establish KLF15 as a central coordinator of cardiac metabolism and ROS clearance.

Growth traits are important economic characteristics of livestock and poultry. In the present study, the expression features of KLF15 and the relationship between KLF15 gene polymorphisms and growth traits in Hu sheep were investigated by using real-time quantitative PCR technology (qPCR), Sanger sequencing, and Kaspar genotyping technology. The qPCR results showed that the KLF15 gene is expressed widely in the tested tissues of Hu sheep, and the expression level of the KLF15 gene in the heart and the muscle was significantly higher than in other tissues ( p  < 0.05). Missense mutation c.62565119 A > G was found in KLF15 , and an association analysis showed that it was correlated with the growth traits (body weight, body height, and body length) of Hu sheep ( p  < 0.05). The body weight, body height, and body length of the sheep carrying the AA genotype were remarkably higher than those of the GG and AG genotypes ( p  < 0.05). These results showed that novel polymorphisms at the KLF15 gene can be used as a genetic marker of growth traits of Hu sheep.

Successful muscle regeneration following injury is essential for functional homeostasis of skeletal muscles. Krüppel-like factor 15 (KLF15) is a metabolic transcriptional regulator in the muscles. However, little is known regarding its function in muscle regeneration. Here, we examined microarray datasets from the Gene Expression Omnibus database, which indicated downregulated KLF15 in muscles from patients with various muscle diseases. Additionally, we found that Klf15 knockout (Klf15KO) impaired muscle regeneration following injury in mice. Furthermore, KLF15 expression was robustly induced during myoblast differentiation. Myoblasts with KLF15 deficiency showed a marked reduction in their fusion capacity. Unbiased transcriptome analysis of muscles on day 7 postinjury revealed downregulated genes involved in cell differentiation and metabolic processes in Klf15KO muscles. The FK506-binding protein 51 (FKBP5), a positive regulator of myoblast differentiation, was ranked as one of the most strongly downregulated genes in the Klf15KO group. A mechanistic search revealed that KLF15 binds directly to the promoter region of FKBP5 and activates FKBP5 expression. Local delivery of FKBP5 rescued the impaired muscle regeneration in Klf15KO mice. Our findings reveal a positive regulatory role of KLF15 in myoblast differentiation and muscle regeneration by activating FKBP5 expression. KLF15 signaling may be a novel therapeutic target for muscle disorders associated with injuries or diseases., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Atrial fibrillation (AF) represents the most common type of clinical cardiac arrhythmia and substantially increases the risks of cerebral stroke, heart failure and death. Accumulating evidence has convincingly demonstrated the strong genetic basis of AF, and an increasing number of pathogenic variations in over 50 genes have been causally linked to AF. Nevertheless, AF is of pronounced genetic heterogeneity, and the genetic determinants underpinning AF in most patients remain obscure. In the current investigation, a Chinese pedigree with AF as well as ventricular arrhythmias and hypertrophic cardiomyopathy was recruited. Whole exome sequencing and bioinformatic analysis of the available family members were conducted, and a novel heterozygous variation in the KLF15 gene (encoding Krüppel-like factor 15, a transcription factor critical for cardiac electrophysiology and structural remodeling), NM_014079.4: c.685A>T; p.(Lys229*), was identified. The variation was verified by Sanger sequencing and segregated with autosomal dominant AF in the family with complete penetrance. The variation was absent from 300 unrelated healthy subjects used as controls. In functional assays using a dual-luciferase assay system, mutant KLF15 showed neither transcriptional activation of the KChIP2 promoter nor transcriptional inhibition of the CTGF promoter, alone or in the presence of TGFB1, a key player in the pathogenesis of arrhythmias and cardiomyopathies. The findings indicate KLF15 as a new causative gene responsible for AF as well as ventricular arrhythmias and hypertrophic cardiomyopathy, and they provide novel insight into the molecular mechanisms underlying cardiac arrhythmias and hypertrophic cardiomyopathy.

Beyond their contribution as fundamental building blocks of life, branched-chain amino acids (BCAAs) play a critical role in physiologic and pathologic processes. Importantly, BCAAs are associated with insulin resistance, obesity, cardiovascular disease, and genetic disorders. However, several metabolome-wide studies in recent years could not attribute alterations in systemic BCAAs as the sole driver of endocrine perturbations, suggesting that a snapshot of global BCAA changes does not always reveal the underlying modifications. Because enzymes catabolizing BCAAs have a unique distribution, it is plausible that the tissue-specific roles of BCAA-catabolic enzymes could precipitate changes in systemic BCAA levels, flux, and action. We review the genetic and pharmacological approaches dissecting the role of BCAA-catabolic enzyme dysfunctions. We summarized emerging evidence on BCAA metabolic intermediates, tissue specificity of BCAA-catabolizing enzymes, and crosstalk between different metabolites in driving metabolic maladaptation in health and pathology. This review substantiates the understanding that tissue-specific dysfunction of the BCAA-catabolic enzymes and accumulating intermediary metabolites could act as better surrogates of metabolic imbalances, highlighting the biochemical communication among the nutrient triad of BCAAs, glucose, and fatty acid. [ABSTRACT FROM AUTHOR]