bims-kishpe 2024-12-15 papers

bims-kishpe

Biomed News

on HSP70 role in hypoxia and metabolism in ECs

Issue of 2024–12–15
fifteen papers selected by
Alia Ablieh, Universität Heidelberg

Sex-mediated effects of transglutaminase 2 inhibition on endothelial function in human resistance arteries from diabetic and non-diabetic patients.
Post-transcriptional regulation of IFI16 promotes inflammatory endothelial pathophenotypes observed in pulmonary arterial hypertension.
Targeting DTX2/UFD1-mediated FTO degradation to regulate antitumor immunity.
Endothelial KDM5B Regulated by Piezo1 Contributes to Disturbed Flow Induced Atherosclerotic Plaque Formation.
ATP citrate lyase drives vascular remodeling in systemic and pulmonary vascular diseases through metabolic and epigenetic changes.
Alk1/Endoglin signaling restricts vein cell size increases in response to hemodynamic cues.
PPAR-α regulates metabolic remodelling and participates in myocardial fibrosis in patients with atrial fibrillation of rheumatic heart disease.
Downregulation of HSPA12A protects heart against sepsis through suppressing mTOR-mediated inflammatory response in cardiomyocytes.
Knockdown of KLF6 ameliorates myocardial infarction by regulating autophagy via transcriptional regulation of PTTG1.
Live Cell Imaging of Human Liver Fibrosis using Hepatic Micro-Organoids.
Endoplasmic reticulum stress in acute lung injury and pulmonary fibrosis.
Molecular signature-based labeling techniques for vascular endothelial cells.
Epigenetic regulation of mitochondrial fission and cardiac fibrosis via sFRP3 promoter methylation.
The matrix protease ADAMTS1 is transcriptionally activated by KLF6 and contributes to cardiac fibrosis in non-ischemic cardiomyopathy.
Screening and identification of gene expression in large cohorts of clinical tissue samples unveils the major involvement of EZH2 and SOX2 in lung cancer.

Clin Sci (Lond). 2024 Dec 12. pii: CS20242001. [Epub ahead of print]

Sex-mediated effects of transglutaminase 2 inhibition on endothelial function in human resistance arteries from diabetic and non-diabetic patients.

Khatera Saii, Judit Prat-Duran, Ulf Simonsen, Anders Riegels Knudsen, Jonas Amstrup Funder, Niels Henrik Buus, Estefano Pinilla.

  Transglutaminase 2 (TG2) is an enzyme with multiple conformations. In its open conformation, TG2 exhibits transamidase activity linked to fibrosis, arterial remodeling, and endothelial dysfunction, a process enhanced by high glucose in endothelial cells. However, the closed conformation of TG2 contributes to transmembrane signaling and nitric oxide (NO)-dependent vasorelaxation. LDN 27219, a reversible allosteric inhibitor, stabilizes TG2 in its closed conformation.  We examined whether pharmacological modulation of TG2 into its closed conformation induces vasorelaxation and enhances endothelium-dependent and independent relaxation in resistance arteries from age-matched diabetic (n=14) and non-diabetic patients (n=14) (age 71 (SEM: ±2).</p>  Subcutaneous arteries (diameter 133-1013 µm) were isolated from abdominal fat biopsies. TG2 mRNA expression and transamidase activity were assessed via RT-qPCR and 5-biotin(amido)pentylamine (5-BP) incorporation, while vascular reactivity was measured using wire myography. TG2 mRNA was highly expressed without significant differences between the groups and LDN 27219 induced concentration-dependent vasorelaxation in arteries from both groups. Sex-specific analysis revealed that potentiation of acetylcholine-induced vasorelaxation by LDN 27219 was driven by increased TG2 expression in non-diabetic females, while no effect was observed in arteries from non-diabetic males. Among diabetic patients, LDN 27219 increased maximal acetylcholine-induced vasorelaxation in males only. LDN 27219 did not affect endothelium-independent relaxation to sodium nitroprusside in either group.</p> In conclusion, TG2 is expressed in human resistance arteries, and LDN 27219 induced vasorelaxation, selectively enhancing ACh relaxation in non-diabetic females, likely due to increased TG2 expression. This finding underscores the importance of sex differences in TG2 modulation of vasorelaxation.

Keywords:  Transglutaminase; endothelial cells; nitric oxide; vasodilation

DOI:  https://doi.org/10.1042/CS20242001
Am J Physiol Lung Cell Mol Physiol. 2024 Dec 10.

Post-transcriptional regulation of IFI16 promotes inflammatory endothelial pathophenotypes observed in pulmonary arterial hypertension.

Rashmi J Rao, Jimin Yang, Siyi Jiang, Wadih El-Khoury, Neha Hafeez, Satoshi Okawa, Yi Yin Tai, Ying Tang, Yassmin Al Aaraj, John C Sembrat, Stephen Y Chan.

  Pulmonary arterial hypertension (PAH) is a progressive disease driven by endothelial cell inflammation and dysfunction, resulting in the pathological remodeling of the pulmonary vasculature. Innate immune activation has been linked to PAH development; however, the regulation, propagation, and reversibility of the induction of inflammation in PAH is poorly understood. Here, we demonstrate a role for interferon inducible protein 16 (IFI16), an innate immune sensor, as a modulator of endothelial inflammation in pulmonary hypertension, utilizing human pulmonary artery endothelial cells (PAECs). Inflammatory stimulus of PAECs with IL-1b up-regulates IFI16 expression, inducing proinflammatory cytokine up-regulation and cellular apoptosis. IFI16 mRNA stability is regulated by post-transcriptional m6A modification, mediated by Wilms' tumor 1-associated protein (WTAP), a structural stabilizer of the methyltransferase complex, via regulation of m6A methylation of IFI16. Additionally, m6A levels are increased in the peripheral blood mononuclear cells of PAH patients compared to control, indicating that quantifying this epigenetic change in patients may hold potential as a biomarker for disease identification. In summary, our study demonstrates IFI16 mediates inflammatory endothelial pathophenotypes seen in pulmonary arterial hypertension.

Keywords:  endothelial; inflammation; m6A methylation; pulmonary hypertension

DOI:  https://doi.org/10.1152/ajplung.00048.2024
Proc Natl Acad Sci U S A. 2024 Dec 17. 121(51): e2407910121

Targeting DTX2/UFD1-mediated FTO degradation to regulate antitumor immunity.

Yan-Hong Cui, Jiangbo Wei, Hao Fan, Wenlong Li, Lijie Zhao, Emma Wilkinson, Jack Peterson, Lishi Xie, Zhongyu Zou, Seungwon Yang, Mark A Applebaum, Justin Kline, Jing Chen, Chuan He, Yu-Ying He.

  Here, we show that vitamin E succinate (VES) acts as a degrader for the m6A RNA demethylase fat mass and obesity-associated protein (FTO), thus suppressing tumor growth and resistance to immunotherapy. FTO is ubiquitinated by its E3 ligase DTX2, followed by UFD1 recruitment and subsequent degradation in the proteasome. VES binds to FTO and DTX2, leading to enhanced FTO-DTX2 interaction, FTO ubiquitination, and degradation in FTO-dependent tumor cells. VES suppressed tumor growth and enhanced antitumor immunity and response to immunotherapy in vivo in mouse models. Genetic FTO knockdown or VES treatment increased m6A methylation in the LIF (Leukemia Inhibitory Factor) gene and decreased LIF mRNA decay, and thus sensitized melanoma cells to T cell-mediated cytotoxicity. Taken together, our findings reveal the underlying molecular mechanism for FTO protein degradation and identify a dietary degrader for FTO that inhibits tumor growth and overcomes immunotherapy resistance.

Keywords:  DTX2; FTO; UFD1; m6A RNA methylation; ubiquitin-mediated proteasomal degradation

DOI:  https://doi.org/10.1073/pnas.2407910121
J Cell Mol Med. 2024 Dec;28(23): e70237

Endothelial KDM5B Regulated by Piezo1 Contributes to Disturbed Flow Induced Atherosclerotic Plaque Formation.

Lili Wu, Shanshan Jiang, Xiao Zhou, Wei Li, Jiaqi Ke, Ziting Liu, Lijie Ren, Qiongyu Lu, Fengchan Li, Chaojun Tang, Li Zhu.

  Epigenetic modifications play an important role in disturbed flow (d-flow) induced atherosclerotic plaque formation. By analysing a scRNA-seq dataset of the left carotid artery (LCA) under d-flow conditions, we found that Jarid1b (KDM5B) was upregulated primarily in a subcluster of endothelial cells in response to d-flow stimulation. We therefore investigated the mechanism of KDM5B expression and the role of KDM5B in endothelial cell. Intriguingly, activation of Piezo1, a major endothelial mechanosensor, was found to promote KDM5B expression, which was reversed by Piezo1 inhibition in HUVECs. Downstream of Piezo1, ETS1 expression and c-JUN phosphorylation were enhanced by d-flow or Piezo1 activation, leading to an increase in KDM5B expression. Furthermore, knockdown of either KDM5B or Piezo1 was found to prevent d-flow induced H3K4me3 demethylation, which was supported by the pharmacological inhibition of Piezo1 in HUVECs. RNA sequencing on shKdm5b HUVECs implied that KDM5B is associated with endothelial inflammation and atherosclerosis. Using partial carotid ligation surgery on Kdm5bf/f Cdh5cre mice with mAAV-PCSK9D377Y infected, we showed that endothelial KDM5B deficiency reduced atherosclerotic lesions in hypercholesterolemic mice. Our findings indicate that endothelial KDM5B expression induced by d-flow via the Piezo1 pathway promotes atherosclerotic plaque formation, providing targets for the prevention or therapeutic intervention of atherosclerosis.

Keywords:  KDM5B; Piezo1; atherosclerosis; disturbed flow; endothelial cells

DOI:  https://doi.org/10.1111/jcmm.70237
Sci Transl Med. 2024 Dec 11. 16(777): eado7824

ATP citrate lyase drives vascular remodeling in systemic and pulmonary vascular diseases through metabolic and epigenetic changes.

Yann Grobs, Charlotte Romanet, Sarah-Eve Lemay, Alice Bourgeois, Pierre Voisine, Charlie Theberge, Melanie Sauvaget, Sandra Breuils-Bonnet, Sandra Martineau, Reem El Kabbout, Chanil Valasarajan, Prakash Chelladurai, Andreanne Pelletier, Manon Mougin, Elizabeth Dumais, Jean Perron, Nicolas Flamand, François Potus, Steeve Provencher, Soni Savai Pullamsetti, Olivier Boucherat, Sebastien Bonnet.

ATP citrate lyase (ACLY), a crucial enzyme in de novo lipid synthesis and histone acetylation, plays a key role in regulating vascular smooth muscle cell (VSMC) proliferation and survival. We found that human coronary and pulmonary artery tissues had up-regulated ACLY expression during vascular remodeling in coronary artery disease and pulmonary arterial hypertension. Pharmacological and genetic inhibition of ACLY in human primary cultured VSMCs isolated from the coronary arteries of patients with coronary artery diseases and from the distal pulmonary arteries of patients with pulmonary arterial hypertension resulted in reduced cellular proliferation and migration and increased susceptibility to apoptosis. These cellular changes were linked to diminished glycolysis, reduced lipid synthesis, impairment in general control nonrepressed protein 5 (GCN5)-dependent histone acetylation and suppression of the transcription factor FOXM1. In vivo studies using a pharmacological inhibitor and VSMC-specific Acly knockout mice showed that ACLY inhibition alleviated vascular remodeling. ACLY inhibition alleviated remodeling in carotid injury and ligation models in rodents and attenuated pulmonary arterial hypertension in Sugen/hypoxia rat and mouse models. Moreover, ACLY inhibition showed improvements in vascular remodeling in human ex vivo models, which included cultured human coronary artery and saphenous vein rings as well as precision-cut lung slices. Our results propose ACLY as a novel therapeutic target for treating complex vascular diseases, offering promising avenues for future clinical intervention.

DOI: https://doi.org/10.1126/scitranslmed.ado7824
Angiogenesis. 2024 Dec 10. 28(1): 5

Alk1/Endoglin signaling restricts vein cell size increases in response to hemodynamic cues.

Zeenat Diwan, Jia Kang, Emma Tsztoo, Arndt F Siekmann.

  Hemodynamic cues are thought to control blood vessel hierarchy through a shear stress set point, where flow increases lead to blood vessel diameter expansion, while decreases in blood flow cause blood vessel narrowing. Aberrations in blood vessel diameter control can cause congenital arteriovenous malformations (AVMs). We show in zebrafish embryos that while arteries behave according to the shear stress set point model, veins do not. This behavior is dependent on distinct arterial and venous endothelial cell (EC) shapes and sizes. We show that arterial ECs enlarge more strongly when experiencing higher flow, as compared to vein cells. Through the generation of chimeric embryos, we discover that this behavior of vein cells depends on the bone morphogenetic protein (BMP) pathway components Endoglin and Alk1. Endoglin (eng) or alk1 (acvrl1) mutant vein cells enlarge when in normal hemodynamic environments, while we do not observe a phenotype in either acvrl1 or eng mutant ECs in arteries. We further show that an increase in vein diameters initiates AVMs in eng mutants, secondarily leading to higher flow to arteries. These enlarge in response to higher flow through increasing arterial EC sizes, fueling the AVM. This study thus reveals a mechanism through which BMP signaling limits vein EC size increases in response to flow and provides a framework for our understanding of how a small number of mutant vein cells via flow-mediated secondary effects on wildtype arterial ECs can precipitate larger AVMs in disease conditions, such as hereditary hemorrhagic telangiectasia (HHT).

Keywords:  Alk1; Artery; Endoglin; Endothelial Cell Size; Hereditary hemorrhagic telangiectasia; Shear Stress Set Point; Vein; Zebrafish

DOI:  https://doi.org/10.1007/s10456-024-09955-3
Arch Med Sci. 2024 ;20(5): 1461-1471

PPAR-α regulates metabolic remodelling and participates in myocardial fibrosis in patients with atrial fibrillation of rheumatic heart disease.

Xiaoying Hu, Daisong Jiang, Zheng Zhang, Zhenmei An.

   Introduction: This study will explore the correlation of peroxisome proliferator activated receptor-α (PPAR-α) regulation of metabolic remodelling in the myocardial fibrosis of atrial fibrillation (AF) in rheumatic heart disease.
Material and methods: The left atrial appendage tissues were evaluated by Masson staining for fibrosis degree, and Western Blot was used to detect the expression of proteins related to glucose metabolism disorder, lipid metabolism abnormality, and mitochondrial dysfunction. The myocardial fibroblasts were established by stimulation with ANG II, and the PPAR-α agonist GW7647 was administered. The changes of phenotype transformation of myocardial fibroblasts were detected by cellular immunofluorescence, the secretion level of supernatant collagen was detected by ELISA. Finally, the correlation between PPAR-α protein expression and myocardial fibrosis was analysed and a conclusion was drawn.
Results: Masson staining showed that the degree of myocardial fibrosis in patients with AF was significantly increased; WB analysis showed that there were statistically significant differences in protein expression related to glucose metabolism disorder, lipid metabolism abnormality, and mitochondrial dysfunction. There was a correlation between PPAR-α protein expression and myocardial fibrosis (r = -0.5322, p < 0.0001). After stimulation with PPAR-α agonist GW7647, the phenotypic differentiation of myocardial fibro-blasts into myofibroblasts was inhibited. The protein expression related to mitochondrial dysfunction was statistically different.
Conclusions: This study found that there is a negative correlation between the expression of PPAR-α protein and myocardial fibrosis in rheumatic heart disease AF, which plays a protective role. PPAR-α may participate in the pathogenesis of myocardial fibrosis in rheumatic heart disease AF by regulating glucose metabolism, lipid metabolism, and mitochondrial function.

Keywords:  atrial fibrillation; correlation study; metabolic remodelling; myocardial fibrosis; peroxisome proliferator activated receptor-α; rheumatic heart disease

DOI:  https://doi.org/10.5114/aoms/181134
Int Immunopharmacol. 2024 Dec 04. pii: S1567-5769(24)02243-4. [Epub ahead of print]145 113721

Downregulation of HSPA12A protects heart against sepsis through suppressing mTOR-mediated inflammatory response in cardiomyocytes.

Yunfan Li, Xiaojin Zhang, Guohua Jiang, Xinxu Min, Qiuyue Kong, Li Liu, Jun Wu, Zhengnian Ding.

   OBJECTIVE: Over-activated immune response in hearts is the main pathological feature of septic cardiomyopathy, a fatal complication of sepsis with high mortality. Autophagy is capable to limit immune response by removing inflammatory mediators. Heat shock protein A12A (HSPA12A) encodes an atypical member of HSP70 family. This study aimed to investigate the role of HSPA12A in septic cardiomyopathy.
METHODS: Sepsis was induced by cecal ligation and puncture (CLP) for 6 h in mice in vivo or by LPS treatment for 24 h in primary cardiomyocytes in vitro. HSPA12A knockout (Hspa12a-/-) mice were generated by cre-loxp system. Echocardiography was performed to assess cardiac function. TUNEL and propidium iodide (PI) staining was used to indicate cardiomyocyte death. Inflammation-related factors were examined by qPCR and immunoblotting. Autophagy was evaluated by levels of LC3-II and p62.
RESULTS: Sepsis decreased HSPA12A expression in hearts and cardiomyocytes, while HSPA12A knockout in mice attenuated sepsis-induced cardiomyocyte death and cardiac dysfunction. Sepsis-induced activation of TLR4/MyD88/NF-κB-mediated inflammation was inhibited in hearts by HSPA12A knockout whereas was enhanced by HSPA12A overexpression in cardiomyocytes. Moreover, HSPA12A overexpression activated mTOR and inhibited autophagy in cardiomyocytes, while inhibition of mTOR by rapamycin diminished the HSPA12A-induced autophagy inhibition, inflammation activation, and cardiomyocyte death in septic cardiomyocytes.
CONCLUSION: Downregulation of HSPA12A inhibited mTOR to activated autophagy, thereby suppressed inflammatory response, and ultimately attenuated septic cardiomyopathy. Our findings identified HSPA12A as a driver for septic cardiomyopathy development, and strategies that inhibit HSPA12A in cardiomyocytes might be a potential therapeutic intervention.

Keywords:  Autophagy; Cardiomyocyte; Cardiomyopathy; HSPA12A; Inflammation; Sepsis

DOI:  https://doi.org/10.1016/j.intimp.2024.113721
Am J Physiol Cell Physiol. 2024 Dec 09.

Knockdown of KLF6 ameliorates myocardial infarction by regulating autophagy via transcriptional regulation of PTTG1.

Yixin Chen, Qian Zhao, Tengfei Wu, Feifei Sun, Weineng Fu.

  Krüppel-like factor 6 (KLF6) knockdown provides protection against kidney ischemia/reperfusion (I/R) injury and ischemic stroke. However, it is unclear whether it plays a role in myocardial infarction (MI) remains unknown. Here, the expression of KLF6 was analyzed using the GEO database and determined in patients with MI. The impact of KLF6 knockdown was further confirmed in in vivo and >in vitro models of MI. The interaction between KLF6 and PTTG1 was also evaluated. According to the GEO database, KLF6 expression was found to be upregulated in mouse hearts after MI compared to sham-operated mice. The upregulation of KLF6 in hearts from mice post-MI and in patients with MI was confirmed. KLF6 knockdown was found to alleviate myocardial injury, diminish infarct size, and suppress apoptosis and autophagy in mice with MI. Additionally, inactivation of the AMPK/mTOR signaling was observed after KLF6 knockdown in mice with MI. In an in vitro model of MI, knockdown of KLF6 increased cell survival and inhibited autophagy through the AMPK/mTOR pathway. Additionally, KLF6 interacted with the promoter of PTTG1 and negatively regulated its expression. Knockdown of PTTG1 abolished the function of KLF6 knockdown in vitro. This study demonstrates the protective effect of KLF6 knockdown against MI, which is attributed to the elevation of PTTG1 expression and inhibition of the AMPK/mTOR pathway. These findings provide a novel insight into MI treatment.

Keywords:  AMPK/mTOR signaling; KLF6; PTTG1; XXX; autophagy; myocardial infarction

DOI:  https://doi.org/10.1152/ajpcell.00191.2024
JCI Insight. 2024 Dec 10. pii: e187099. [Epub ahead of print]

Live Cell Imaging of Human Liver Fibrosis using Hepatic Micro-Organoids.

Yuan Guan, Zhuoqing Fang, Angelina Hu, Sarah Roberts, Meiyue Wang, Wenlong Ren, Patrik K Johansson, Sarah C Heilshorn, Annika Enejder, Gary Peltz.

  Due to the limitations of available in vitro systems and animal models, we lack a detailed understanding of the pathogenetic mechanisms and have minimal treatment options for liver fibrosis. Therefore, we engineered a live cell imaging system that assesses fibrosis in a human multi-lineage hepatic organoid in a microwell (i.e., microHOs). Transcriptomic analysis revealed that TGFβ1 converted mesenchymal cells in microHOs into myofibroblast-like cells resembling those in fibrotic human liver tissue. When pro-fibrotic intracellular signaling pathways were examined, the anti-fibrotic effect of receptor-specific tyrosine kinase inhibitors was limited to the fibrosis induced by the corresponding growth factor, which indicates their anti-fibrotic efficacy would be limited to fibrotic diseases solely mediated by that growth factor. Based upon transcriptomic and transcription factor activation analyses in microHOs, GSK3β and p38 MAPK inhibitors were identified as potential new broad-spectrum therapies for liver fibrosis. Other new therapies could subsequently be identified using the microHO system.

Keywords:  Fibrosis; Hepatology

DOI:  https://doi.org/10.1172/jci.insight.187099
FASEB J. 2024 Dec 15. 38(23): e70232

Endoplasmic reticulum stress in acute lung injury and pulmonary fibrosis.

Zhiheng Sun, Wanyu He, Huiwen Meng, Peizhi Li, Junxing Qu.

  Pulmonary fibrosis (PF) is a progressive and irreversible lung disease that leads to diminished lung function, respiratory failure, and ultimately death and typically has a poor prognosis, with an average survival time of 2 to 5 years. Related articles suggested that endoplasmic reticulum (ER) stress played a critical role in the occurrence and progression of PF. The ER is responsible for maintaining protein homeostasis. However, factors such as aging, hypoxia, oxidative stress, or inflammation can disrupt this balance, promoting the accumulation of misfolded proteins in the ER and triggering ER stress. To cope with this situation, cells activate the unfolded protein response (UPR). Since acute lung injury (ALI) is one of the key onset events of PF, in this review, we will discuss the role of ER stress in ALI and PF by activating multiple signaling pathways and molecular mechanisms that affect the function and behavior of different cell types, with a focus on epithelial cells, fibroblasts, and macrophages. Linking ER stress to these cell types may broaden our understanding of the mechanisms underlying lung fibrosis and help us target these cells through these mechanisms. The relationship between ER stress and PF is still evolving, and future research will explore new strategies to regulate UPR pathways, providing novel therapeutic targets.

Keywords:  acute lung injury; endoplasmic reticulum stress; epithelial cells; fibroblasts; macrophages; pulmonary fibrosis

DOI:  https://doi.org/10.1096/fj.202401849RR
Acta Histochem. 2024 Dec 06. pii: S0065-1281(24)00090-4. [Epub ahead of print]127(1): 152222

Molecular signature-based labeling techniques for vascular endothelial cells.

Krutika H Dobariya, Divya Goyal, Hemant Kumar.

  Vascular endothelial cells (VECs) play a crucial role in the development and maintenance of vascular biology specific to the tissue types. Molecular signature-based labeling and imaging of VECs help researchers understand potential mechanisms linking VECs to disease pathology, serving as valuable biomarkers in clinical settings and trials. Labeling techniques involve selectively tagging or marking VECs for visualization. Immunolabeled employs antibodies that specifically bind to VECs markers, while fluorescent tracers or dyes can directly label VECs for imaging. Some techniques use specific carbohydrate residues on cell surface, while others employ endothelial-specific promoters to express fluorescent proteins. Additionally, VEC can be labeled with contrast agents, radiolabeled tracers, and nanoparticles. The choice of labeling technique depends on study context, including whether it involves animal models, in vitro cell cultures, or clinical applications. Herein, we discussed the various labeling methods utilized to label VECs and the techniques to visualize them.

Keywords:  Dye; Labeling; Lectin; Molecular Signature; Nanoparticle; Quantum Dots; Transgene; Vascular Endothelial cells

DOI:  https://doi.org/10.1016/j.acthis.2024.152222
Cell Mol Life Sci. 2024 Dec 07. 81(1): 483

Epigenetic regulation of mitochondrial fission and cardiac fibrosis via sFRP3 promoter methylation.

Shun-Xiang Jiang, Ze-Yu Zhou, Bin Tu, Kai Song, Li-Chan Lin, Zhi-Yan Liu, Wei Cao, Jian-Yuan Zhao, Hui Tao.

  In the process of cardiac fibrosis, the balance between the Wnt/β-catenin signalling pathway and Wnt inhibitory factor genes plays an important role. Secreted frizzled-related protein 3 (sFRP3), a Wnt inhibitory factor, has been linked to epigenetic mechanisms. However, the underlying role of epigenetic regulation of sFRP3, which is crucial in fibroblast proliferation and migration, in cardiac fibrosis have not been elucidated. Therefore, we aimed to investigate epigenetic and transcription of sFRP3 in cardiac fibrosis. Using clinical samples and animal models, we investigated the role of sFRP3 promoter methylation in potentially enhancing cardiac fibrosis. We also attempted to characterize the underlying mechanisms using an isoprenaline-induced cardiac fibrosis mouse model and cultured primary cardiac fibroblasts. Hypermethylation of sFRP3 was associated with perpetuation of fibroblast activation and cardiac fibrosis. Additionally, mitochondrial fission, regulated by the Drp1 protein, was found to be significantly altered in fibrotic hearts, contributing to fibroblast proliferation and cardiac fibrosis. Epigenetic modification of sFRP3 promoter methylation also influenced mitochondrial dynamics, linking sFRP3 repression to excessive mitochondrial fission. Moreover, sFRP3 hypermethylation was mediated by DNA methyltransferase 3A (DNMT3A) in cardiac fibrosis and fibroblasts, and DNMT3A knockdown demethylated the sFRP3 promoter, rescued sFRP3 loss, and ameliorated the isoprenaline-induced cardiac fibrosis and cardiac fibroblast proliferation, migration and mitochondrial fission. Mechanistically, DNMT3A was shown to epigenetically repress sFRP3 expression via promoter methylation. We describe a novel epigenetic mechanism wherein DNMT3A represses sFRP3 through promoter methylation, which is a critical mediator of cardiac fibrosis and mitochondrial fission. Our findings provide new insights for the development of preventive measures for cardiac fibrosis.

Keywords:  Cardiac fibroblast; Cardiac fibrosis; DNMT3A; Migration; Mitochondrial fission; Proliferation; SFRP3

DOI:  https://doi.org/10.1007/s00018-024-05516-5
Life Sci. 2024 Dec 04. pii: S0024-3205(24)00885-3. [Epub ahead of print]361 123295

The matrix protease ADAMTS1 is transcriptionally activated by KLF6 and contributes to cardiac fibrosis in non-ischemic cardiomyopathy.

Nan Li, Chenghao Zhu, Yujia Xue, Naxia Chen, Wenping Xu, Mingzi Song, Mengwen Qi, Shang Huang, Mingming Fang.

   AIMS: Aberrant cardiac fibrosis, defined as excessive production and deposition of extracellular matrix (ECM), is mediated by myofibroblasts. ECM-producing myofibroblasts are primarily derived from resident fibroblasts during cardiac fibrosis. The mechanism underlying fibroblast-myofibroblast transition is not fully understood.
METHODS: Cardiac fibrosis was induced by transverse aortic constriction (TAC) or by angiotensin II (Ang II) infusion in C57B6/j mice. Cellular transcriptome was evaluated by RNA-seq and CUT&Tag-seq.
RESULTS: Integrated transcriptomic screening revealed that a disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1) was a novel transcriptional target for Kruppel-like factor 6 (KLF6) in cardiac fibroblasts. Treatment with either TGF-β or Ang II up-regulated ADAMTS1 expression. KLF6 knockdown attenuated whereas KLF6 over-expression enhanced ADAMTS1 induction. ChIP assay and reporter assay showed that KLF6 was recruited to the ADAMTS1 promoter to activate its transcription. Consistently, ADAMTS1 knockdown suppressed fibroblast-myofibroblast transition in vitro. Importantly, myofibroblast-specific ADAMTS1 depletion attenuated cardiac fibrosis and normalized heart function in mice.
SIGNIFICANCE: In conclusion, our data demonstrate that ADAMTS1, as a downstream target of KLF6, contributes to cardiac fibrosis by regulating fibroblast-myofibroblast transition.

Keywords:  Cardiac fibroblast; Cardiac fibrosis; Heart failure; Transcription factor; Transcriptional regulation

DOI:  https://doi.org/10.1016/j.lfs.2024.123295
Cancer Genet. 2024 Dec 02. pii: S2210-7762(24)00151-0. [Epub ahead of print]290-291 16-35

Screening and identification of gene expression in large cohorts of clinical tissue samples unveils the major involvement of EZH2 and SOX2 in lung cancer.

Niharika, Ankan Roy, Ratan Sadhukhan, Samir Kumar Patra.

  Lung adenocarcinoma (LUAD), the primary subtype of Non-Small Cell Lung Cancer (NSCLC), accounts for 80 % to 85 % of cases. Due to suboptimal screening method, LUAD is often detected in late stage, leading to aggressive progression and poor outcomes. Therefore, early disease prognosis for the LUAD is high priority. In order to identify early detection biomarkers, we conducted a meta-analysis of mRNA expression TCGA and GTEx datasets from LUAD patients. A total of 795 differentially expressed genes (DEGs) were identified by exploring the Network-Analyst tool and utilizing combined effect size methods. DEGs refer to genes whose expression levels are significantly different (either higher or lower) compared to their normal baseline expression levels. KEGG pathway enrichment analysis highlighted the TNF signaling pathway as being prominently associated with these DEGs. Subsequently, using the MCODE and CytoHubba plugins in Cytoscape software, we filtered out the top 10 genes. Among these, SOX2 was the only gene exhibiting higher expression, while the others were downregulated. Consequently, our subsequent research focused on SOX2. Further transcription factor-gene network analysis revealed that enhancer of zeste homolog 2 (EZH2) is a significant partner of SOX2, potentially playing a crucial role in euchromatin-heterochromatin dynamics. Structure of SOX2 protein suggest that it is a non-druggable transcription factor, literature survey suggests the same. SOX2 is considered challenging to target directly, or "non-druggable," because of several intrinsic properties that make it difficult to design effective therapeutic agents against it. The primary function of SOX2 is to bind DNA and regulates gene expression. Unlike enzymes or receptors with defined active sites or binding pockets, transcription factors typically have relatively flat or diffuse surfaces that do not offer obvious "pockets" for small molecules to bind effectively. Hence, we drove our focus to investigate on potential drug(s) targeting EZH2. Molecular docking analyses predicted most probable inhibitors of EZH2. We employed several predictive analysis tools and identified GSK343, as a promising inhibitor of EZH2.

Keywords:  Bioinformatics analysis; Biomarkers; EZH2; H3K27me3; LUAD; Molecular docking; PRC2; SOX2

DOI:  https://doi.org/10.1016/j.cancergen.2024.11.006