bims-kishpe 2024-11-17 papers

bims-kishpe

Biomed News

on HSP70 role in hypoxia and metabolism in ECs

Issue of 2024–11–17
sixteen papers selected by
Alia Ablieh, Universität Heidelberg

HIF-1α knockdown attenuates phenotypic transformation and oxidative stress induced by high salt in human aortic vascular smooth muscle cells.
Sustained hypoxia but not intermittent hypoxia induces HIF-1α transcriptional response in human aortic endothelial cells.
Hypoxia-Induced Mitochondrial ROS and Function in Pulmonary Arterial Endothelial Cells.
Regulation of blood pressure by METTL3 via RUNX1b-eNOS pathway in endothelial cells in mice.
Viewing Pulmonary Arterial Hypertension Pathogenesis and Opportunities for Disease-Modifying Therapy Through the Lens of Biomass.
FTO suppresses cardiac fibrosis after myocardial infarction via m6A-mediated epigenetic modification of EPRS.
PI3K p85α/HIF-1α accelerates the development of pulmonary arterial hypertension by regulating fatty acid uptake and mitophagy.
Understanding Endothelial Dysfunction and Its Role in Ischemic Stroke After the Outbreak of Recanalization Therapies.
Stress Granule Assembly in Pulmonary Arterial Hypertension.
Vitamin D receptor and its antiproliferative effect in human pulmonary arterial hypertension.
Cell-state dependent regulation of PPARγ signaling by the transcription factor ZBTB9 in adipocytes.
Extracellular vesicles derived from endothelial progenitor cells modified by Houshiheisan promote angiogenesis and attenuate cerebral ischemic injury via miR-126/PIK3R2.
miR-24-3p secreted as extracellular vesicle cargo by cardiomyocytes inhibits fibrosis in human cardiac microtissues.
Luminal epithelial cells integrate variable responses to aging into stereotypical changes that underlie breast cancer susceptibility.
Lipid sensing by PPARα: Role in controlling hepatocyte gene regulatory networks and the metabolic response to fasting.
Role of STK38L in atrial fibrillation-associated myocardial fibrosis: findings from RNA-seq analysis.

Sci Rep. 2024 Nov 15. 14(1): 28100

HIF-1α knockdown attenuates phenotypic transformation and oxidative stress induced by high salt in human aortic vascular smooth muscle cells.

Wenbin Deng, Shiqiong Huang, Lisha Yu, Bo Gao, Yun Pan, Xue Wang, Lihua Li.

  Increased dietary salt intake is a well-established risk factor for hypertension and related cardiovascular diseases, involving complex vascular remodeling processes. However, the specific role of hypoxia-inducible factor-1α (HIF-1α) in vascular pathophysiology under high-salt conditions remains poorly understood. This study investigates the role of HIF-1α in high-salt-induced vascular remodeling using human aortic vascular smooth muscle cells (HA-VSMCs) cultured in vitro. HA-VSMCs were divided into three groups: high-salt with HIF-1α knockdown (shHIF-1α + HS), negative control (shcontrol), and high-salt (HS). Cell viability, migration, gene expression, and protein levels were evaluated. High-salt conditions significantly increased mRNA expression of α-smooth muscle actin (α-SMA), smooth muscle protein 22 (SM22), angiotensin II type 1 receptor (AT1R), collagen I, and collagen III (p < 0.0001). HIF-1α knockdown partially attenuated these increases, particularly for α-SMA, SM22, and AT1R (p < 0.01). At the protein level, high-salt exposure markedly elevated expression of collagen III, HIF-1α, osteopontin (OPN), and angiotensin II (Ang II) (p < 0.0001). HIF-1α knockdown significantly reduced the high-salt-induced increases in collagen III and HIF-1α protein levels (p < 0.001) but had a limited effect on OPN and Ang II upregulation. Interestingly, SM22 protein expression was significantly decreased under high-salt conditions (p < 0.0001), an effect partially reversed by HIF-1α knockdown (p < 0.0001). These findings demonstrate that high-salt conditions induce complex changes in gene and protein expression in HA-VSMCs, with HIF-1α playing a crucial role in mediating many of these alterations. The study highlights the differential effects of HIF-1α on various markers of vascular remodeling and suggests that HIF-1α may be a potential therapeutic target for mitigating salt-induced vascular pathology. Further research is warranted to elucidate the mechanisms underlying the HIF-1α-dependent and -independent effects observed in this study.

Keywords:  Angiotensin II; Human aortic vascular smooth muscle cell; Hypoxia-inducible factor-1α; Salt; Vascular remodeling

DOI:  https://doi.org/10.1038/s41598-024-79892-0
Mol Omics. 2024 Nov 08.

Sustained hypoxia but not intermittent hypoxia induces HIF-1α transcriptional response in human aortic endothelial cells.

Rengul Cetin-Atalay, Angelo Y Meliton, Yufeng Tian, Kaitlyn A Sun, Parker S Woods, Kun Woo D Shin, Takugo Cho, Alex Gileles-Hillel, Robert B Hamanaka, Gökhan M Mutlu.

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxic environments at the cellular level and is an independent risk factor for the development of cardiovascular disease. Endothelial cell (EC) dysfunction precedes the development of cardiovascular disease; however, the mechanisms by which ECs respond to these intermittent hypoxic events are poorly understood. To better understand EC responses to hypoxia, we examined the effects of sustained hypoxia (SH) and intermittent hypoxia (IH) on the activation of HIF-1α in ECs. While SH stabilized HIF-1α and led to its nuclear localization, IH did not activate HIF-1α and the expression of its target genes. Using RNA-sequencing, we evaluated transcriptional responses of ECs to hypoxia. SH induced the expression of HIF-1α and hypoxia response genes, while IH affected cell-cycle regulation genes. A cytoscape protein-protein interaction network for EC response to hypoxia was created with differentially expressed genes. The network comprises cell-cycle regulation, inflammatory signaling via NF-κB and response to VEGF stimulus subnetworks on which SH and IH had distinct activities. As OSA is associated with elevated catecholamines, we investigated the effect of epinephrine on the EC response to SH and IH. Transcriptomic responses under IH and epinephrine revealed protein-protein interaction networks emphasizing distinct subnetworks, including cytokine-mediated TNFα signaling via NF-κB, Wnt/LRP/DKK signaling and cell cycle regulation. This study reveals differential transcriptomic responses under SH and IH characterised by HIF-1α transcriptional response induced only by SH, but not by IH. The study also features the potential molecular events that may occur at the vascular level in OSA.

DOI: https://doi.org/10.1039/d4mo00142g
Cells. 2024 Nov 01. pii: 1807. [Epub ahead of print]13(21):

Hypoxia-Induced Mitochondrial ROS and Function in Pulmonary Arterial Endothelial Cells.

Harrison Wang, Teng-Yao Song, Jorge Reyes-García, Yong-Xiao Wang.

  Pulmonary artery endothelial cells (PAECs) are a major contributor to hypoxic pulmonary hypertension (PH) due to the possible roles of reactive oxygen species (ROS). However, the molecular mechanisms and functional roles of ROS in PAECs are not well established. In this study, we first used Amplex UltraRed reagent to assess hydrogen peroxide (H2O2) generation. The result indicated that hypoxic exposure resulted in a significant increase in Amplex UltraRed-derived fluorescence (i.e., H2O2 production) in human PAECs. To complement this result, we employed lucigenin as a probe to detect superoxide (O2-) production. Our assays showed that hypoxia largely increased O2- production. Hypoxia also enhanced H2O2 production in the mitochondria from PAECs. Using the genetically encoded H2O2 sensor HyPer, we further revealed the hypoxic ROS production in PAECs, which was fully blocked by the mitochondrial inhibitor rotenone or myxothiazol. Interestingly, hypoxia caused an increase in the migration of PAECs, determined by scratch wound assay. In contrast, nicotine, a major cigarette or e-cigarette component, had no effect. Moreover, hypoxia and nicotine co-exposure further increased migration. Transfection of lentiviral shRNAs specific for the mitochondrial Rieske iron-sulfur protein (RISP), which knocked down its expression and associated ROS generation, inhibited the hypoxic migration of PAECs. Hypoxia largely increased the proliferation of PAECs, determined using Ki67 staining and direct cell number accounting. Similarly, nicotine caused a large increase in proliferation. Moreover, hypoxia/nicotine co-exposure elicited a further increase in cell proliferation. RISP knockdown inhibited the proliferation of PAECs following hypoxia, nicotine exposure, and hypoxia/nicotine co-exposure. Taken together, our data demonstrate that hypoxia increases RISP-mediated mitochondrial ROS production, migration, and proliferation in human PAECs; nicotine has no effect on migration, increases proliferation, and promotes hypoxic proliferation; the effects of nicotine are largely mediated by RISP-dependent mitochondrial ROS signaling. Conceivably, PAECs may contribute to PH via the RISP-mediated mitochondrial ROS.

Keywords:  hypoxia; nicotine; pulmonary artery endothelial cells; pulmonary hypertension

DOI:  https://doi.org/10.3390/cells13211807
Cardiovasc Res. 2024 Nov 12. pii: cvae242. [Epub ahead of print]

Regulation of blood pressure by METTL3 via RUNX1b-eNOS pathway in endothelial cells in mice.

Yanhong Zhang, Xiaoxiao Yang, Mei Lan, Ze Yuan, Shuai Li, Yangping Liu, Cha Han, Ding Ai, Yang Yang, Yi Zhu, Bochuan Li.

AIMS: Endothelial cells regulate vascular tone to control the blood pressure (BP) by producing both relaxing and contracting factors. Previously, we identified methyltransferase-like 3 (METTL3), a primary N6-methyladenosine (m6A) methyltransferase, as a key player in alleviating endothelial atherogenic progression. However, its involvement in BP regulation remains unclear.
METHODS AND RESULTS: To evaluate the role of METTL3 in vivo, mice with EC specific METTL3 deficiency (EC-Mettl3KO) with or without Ang II infusion were used to create a hypertensive model. Functional and MeRIP sequencing analysis were performed to explore the mechanism of METTL3-mediated hypertension. We observed a reduction in endothelial METTL3 activity by Ang II in vitro and in vivo. Endothelial METTL3-deficient mice exhibited higher BP than controls, with no gender disparity observed. The subsequent study primarily conducted in male mice. Through m6A sequencing and functional analysis, we identified m6A modification of various RUNX1 monomers resulted in endothelial dysfunction. Mutations in the 3'UTR region of RUNX1b abolished its luciferase reporter activity, and enhanced eNOS promoter luciferase reporter activity with or without METTL3 overexpression. Overexpression of METTL3 by adeno-associated virus reduced Ang II-induced BP elevation.
CONCLUSION: This study reveals that METTL3 alleviates hypertension through m6A-dependent stabilization of RUNX1b mRNA, leading to upregulation of eNOS, thus underscoring the pivotal role of RNA transcriptomics in the regulation of hypertension.

DOI: https://doi.org/10.1093/cvr/cvae242
JACC Basic Transl Sci. 2024 Oct;9(10): 1252-1263

Viewing Pulmonary Arterial Hypertension Pathogenesis and Opportunities for Disease-Modifying Therapy Through the Lens of Biomass.

Matthew L Steinhauser, Bradley A Maron.

  Fibroproliferative remodeling of distal pulmonary arterioles is a cornerstone characteristic of pulmonary arterial hypertension (PAH). Data from contemporary quantitative imaging suggest that anabolic synthesis of macromolecular substrate, defined here as biomass, is the proximate event that causes vascular remodeling via pathogenic changes to DNA, collagen, cytoskeleton, and lipid membranes. Modifying biomass is achievable but requires tilting the balance in favor of endogenous degradation over synthetic pathways in order to advance the first-ever disease-modifying PAH pharmacotherapy. Viewing PAH pathobiology through the lens of biomass represents an opportunity to decipher novel determinants of disease inception and inform interventions that induce reverse remodeling.

Keywords:  biomass; disease modification; pulmonary arterial hypertension

DOI:  https://doi.org/10.1016/j.jacbts.2024.04.009
Mol Med. 2024 Nov 13. 30(1): 213

FTO suppresses cardiac fibrosis after myocardial infarction via m6A-mediated epigenetic modification of EPRS.

Jian Wang, Yanyan Li, Lijie Deng, Yafang Zha, Song Zhang.

   BACKGROUND: Cardiac fibrosis is common in myocardial infarction (MI), leading to progressive cardiac dysfunction. Studies suggested that the abnormal N6-methyladenosine (m6A) modification induced by fat mass and obesity protein (FTO) is vital in MI. However, the effects of FTO on post-infarction cardiac fibrosis have not been detected.
METHODS: Western blot and quantitative real-time PCR were performed to detect the expression of FTO in the fibrotic tissue of rats. The functions of FTO on collagen biosynthesis were analyzed in vitro and in vivo. The underlying targets of FTO were selected through RNA-seq with m6A-seq. The following dual luciferase reporter assay and RNA stability assay were conducted to investigate the mechanisms of FTO-mediated m6A regulation.
RESULTS: The expression of FTO was decreased in the fibrotic tissue of post-infarction rats. The HIF-1 signal pathway was enriched after MI. HIF-1α could bind to the promoter of FTO and inhibit its expression. Functionally, FTO inhibited collagen synthesis after MI in vitro and in vivo. Mechanistically, EPRS was selected as the underlying target of FTO-induced m6A regulation. IGF2BP3 recognized and bound to the m6A sites of EPRS mRNA, which improved its stability. EPRS was required for cardiac fibrosis induced by FTO silencing.
CONCLUSIONS: FTO, identified as a cardioprotective factor, suppressed collagen synthesis in post-infarction cardiac fibrosis via m6A modification, which provided a new therapeutic strategy for cardiac fibrosis.

Keywords:  Cardiac fibrosis; EPRS; FTO; N6-methyladenosine (m6A)

DOI:  https://doi.org/10.1186/s10020-024-00985-7
Mol Med. 2024 Nov 11. 30(1): 208

PI3K p85α/HIF-1α accelerates the development of pulmonary arterial hypertension by regulating fatty acid uptake and mitophagy.

Chenyang Chen, Sirun Qin, Xiaohua Song, Juan Wen, Wei Huang, Zhe Sheng, Xiaogang Li, Yu Cao.

   BACKGROUND: Pulmonary arterial hypertension (PAH) is characterized by lipid accumulation and mitochondrial dysfunction. This study was designed to investigate the effects of hypoxia-inducible factor-1α (HIF-1α) on fatty acid uptake and mitophagy in PAH.
METHODS: Peripheral blood samples were obtained from PAH patients. Human pulmonary arterial smooth muscle cells and rat cardiac myoblasts H9c2 were subjected to hypoxia treatment. Male Sprague-Dawley rats were treated with monocrotaline (MCT). Right ventricular systolic pressure (RVSP), right ventricular hypertrophy index (RVHI), pulmonary artery remodeling, and lipid accumulation were measured. Cell proliferation and ROS accumulation were assessed. Mitochondrial damage and autophagosome formation were observed. Co-immunoprecipitation was performed to verify the interaction between HIF-1α and CD36/PI3K p85α.
RESULTS: HIF-1α, CD36, Parkin, and PINK1 were upregulated in PAH samples. HIF-1α knockdown or PI3K p85α knockdown restricted the expression of HIF-1α, PI3K p85α, Parkin, PINK1, and CD36, inhibited hPASMC proliferation, promoted H9c2 cell proliferation, reduced ROS accumulation, and suppressed mitophagy. CD36 knockdown showed opposite effects to HIF-1α knockdown, which were reversed by palmitic acid. The HIF-1α activator dimethyloxalylglycine reversed the inhibitory effect of Parkin knockdown on mitophagy. In MCT-induced rats, the HIF-1α antagonist 2-methoxyestradiol (2ME) reduced RVSP, RVHI, pulmonary artery remodeling, lipid accumulation, and mitophagy. Recombinant CD36 abolished the therapeutic effect of 2ME but inhibited mitophagy. Activation of Parkin/PINK1 by salidroside (Sal) promoted mitophagy to ameliorate the pathological features of PAH-like rats, and 2ME further enhanced the therapeutic outcome of Sal.
CONCLUSION: PI3K p85α/HIF-1α induced CD36-mediated fatty acid uptake and Parkin/PINK1-dependent mitophagy to accelerate the progression of experimental PAH.

Keywords:  CD36; Fatty acid intake; HIF-1α; Mitophagy; Pulmonary arterial hypertension

DOI:  https://doi.org/10.1186/s10020-024-00975-9
Int J Mol Sci. 2024 Oct 29. pii: 11631. [Epub ahead of print]25(21):

Understanding Endothelial Dysfunction and Its Role in Ischemic Stroke After the Outbreak of Recanalization Therapies.

Patricia de la Riva, Juan Marta-Enguita, Jon Rodríguez-Antigüedad, Alberto Bergareche, Adolfo López de Munain.

  Despite recent advances in treatment options, stroke remains a highly prevalent and devastating condition with significant socioeconomic impact. Recanalization therapies, including intravenous thrombolysis and endovascular treatments, have revolutionized stroke management and prognosis, providing a promising framework for exploring new therapeutic strategies. Endothelial dysfunction plays a critical role in the pathophysiology, progression, and prognosis of stroke. This review aims to synthesize the current evidence regarding the involvement of the nitric oxide (NO)/endothelium pathway in ischemic stroke, with a particular focus on aging, response to recanalization therapies, and therapeutic approaches. While significant progress has been made in recent years in understanding the relationship between endothelial dysfunction and stroke, many uncertainties persist, and although treatments targeting this pathway are promising, they have yet to demonstrate clear clinical benefits.

Keywords:  endothelium; nitrous oxide; recanalization; stroke

DOI:  https://doi.org/10.3390/ijms252111631
Cells. 2024 Oct 30. pii: 1796. [Epub ahead of print]13(21):

Stress Granule Assembly in Pulmonary Arterial Hypertension.

Kosmas Kosmas, Aimilia Eirini Papathanasiou, Fotios Spyropoulos, Rakhshinda Rehman, Ashley Anne Cunha, Laura E Fredenburgh, Mark A Perrella, Helen Christou.

  The role of stress granules (SGs) in pulmonary arterial hypertension (PAH) is unknown. We hypothesized that SG formation contributes to abnormal vascular phenotypes, and cardiac and skeletal muscle dysfunction in PAH. Using the rat Sugen/hypoxia (SU/Hx) model of PAH, we demonstrate the formation of SG puncta and increased expression of SG proteins compared to control animals in lungs, right ventricles, and soleus muscles. Acetazolamide (ACTZ) treatment ameliorated the disease and reduced SG formation in all of these tissues. Primary pulmonary artery smooth muscle cells (PASMCs) from diseased animals had increased SG protein expression and SG number after acute oxidative stress and this was ameliorated by ACTZ. Pharmacologic inhibition of SG formation or genetic ablation of the SG assembly protein (G3BP1) altered the SU/Hx-PASMC phenotype by decreasing proliferation, increasing apoptosis and modulating synthetic and contractile marker expression. In human PAH lungs, we found increased SG puncta in pulmonary arteries compared to control lungs and in human PAH-PASMCs we found increased SGs after acute oxidative stress compared to healthy PASMCs. Genetic ablation of G3BP1 in human PAH-PASMCs resulted in a phenotypic switch to a less synthetic and more contractile phenotype. We conclude that increased SG formation in PASMCs and other tissues may contribute to PAH pathogenesis.

Keywords:  ACTZ; Caprin1; G3BP1; ISRIB; PAH; stress granules; vascular smooth muscle cells

DOI:  https://doi.org/10.3390/cells13211796
Sci Rep. 2024 11 10. 14(1): 27445

Vitamin D receptor and its antiproliferative effect in human pulmonary arterial hypertension.

Maria Callejo, Daniel Morales-Cano, Miguel A Olivencia, Gema Mondejar-Parreño, Bianca Barreira, Olga Tura-Ceide, Victor G Martínez, Alvaro Serrano-Navarro, Laura Moreno, Nick Morrell, Frédéric Perros, Angeles Vicente, Angel Cogolludo, Francisco Perez-Vizcaino.

Vitamin D (vitD) deficiency is frequently observed in patients with pulmonary arterial hypertension (PAH) and, in these patients, low levels of vitD correlate with worse prognosis. The aim of this study was to examine the expression and the antiproliferative role of vitD receptor (VDR) and its signalling pathway in the human pulmonary vasculature. VDR presence and expression was analyzed in lungs, pulmonary artery smooth muscle cells (PASMC) and endothelial cells (PAEC) from controls and PAH-patients. VDR expression and VDR-target genes were examined in PASMC treated with calcitriol. The antiproliferative effect of 48 h-calcitriol was studied in PASMC by MTT and BrdU assays. VDR is expressed in PASMC. It is downregulated in lungs and in PASMC, but not in PAEC, from PAH-patients compared to non-hypertensive controls. Calcitriol strongly upregulated VDR expression in PASMC and the VDR target genes KCNK3 (encoding TASK1), BIRC5 (encoding survivin) and BMP4. Calcitriol produced an antiproliferative effect which was diminished by silencing or by pharmacological inhibition of survivin or BMPR2, but not of TASK1. In conclusion, the expression of VDR is low in PAH-patients and can be rescued by calcitriol. VDR exerts an antiproliferative effect in PASMC by modulating survivin and the BMP signalling pathway.

DOI: https://doi.org/10.1038/s41598-024-78380-9
J Biol Chem. 2024 Nov 12. pii: S0021-9258(24)02487-6. [Epub ahead of print] 107985

Cell-state dependent regulation of PPARγ signaling by the transcription factor ZBTB9 in adipocytes.

Xuan Xu, Alyssa Charrier, Sunny Congrove, Jeremiah Ockunzzi, David A Buchner.

  Peroxisome proliferator-activated receptor-γ (PPARγ) is a nuclear hormone receptor that is a master regulator of adipocyte differentiation and function. ZBTB9 is a widely expressed but poorly studied transcription factor that was predicted to interact with PPARγ based on large-scale protein-protein interaction experiments. In addition, genome-wide association studies (GWAS) revealed associations between ZBTB9 and BMI, T2D risk, and HbA1c levels. Here we show that Zbtb9 deficiency in mature adipocytes decreased PPARγ activity and protein level, and thus acts as a positive regulator of PPARγ signaling. In contrast, Zbtb9 deficiency in 3T3-L1 and human preadipocytes increased PPARγ levels and enhanced adipogenesis. Transcriptomic and transcription factor binding site analyses of Zbtb9 deficient preadipocytes revealed that the E2F pathway, controlled by the E2F family of transcription factors that are classically associated with cell cycle regulation, was among the most upregulated pathways. E2F1 positively regulates adipogenesis by promoting Pparg expression, independent of its cell cycle role, via direct binding to the Pparg promoter early during adipogenesis. RB phosphorylation (pRB), which regulates E2F activity, was also upregulated in Zbtb9 deficient preadipocytes. Critically, an E2F1 inhibitor blocked the effects of Zbtb9 deficiency on adipogenesis. Collectively, these results demonstrate that Zbtb9 inhibits adipogenesis as a negative regulator of Pparg expression via pRB-E2F signaling. Our findings reveal cell-state dependent roles of ZBTB9 in adipocytes, identifying a new molecule that regulates adipocyte biology as both a positive and negative regulator of PPARγ signaling depending on the cellular context, and thus may be important in the pathogenesis of obesity and T2D.

Keywords:  E2F transcription factor; Type 2 Diabetes; adipocyte; adipogenesis; peroxisome proliferator‐activated receptor (PPAR); transcriptional regulation

DOI:  https://doi.org/10.1016/j.jbc.2024.107985
Sci Rep. 2024 Nov 15. 14(1): 28166

Extracellular vesicles derived from endothelial progenitor cells modified by Houshiheisan promote angiogenesis and attenuate cerebral ischemic injury via miR-126/PIK3R2.

Yawen Zhang, Qiuyue Yang, Hongfa Cheng, Ying Zhang, Yahui Xie, Qiuxia Zhang.

  Angiogenesis following cerebral ischemia is crucial for restoring blood supply to the ischemic region. Extracellular vesicles (EVs) derived from endothelial progenitor cells (EPCs) offer potential therapeutic benefits in the treatment of cerebral ischemia. Houshiheisan (HSHS) has been shown to improve clinical outcomes in ischemic stroke patients, reduce cerebral ischemic damage in rats, and protect endothelial cells. However, the potential effects of HSHS-modified EPC-derived EVs (EVsHSHS) for cerebral ischemia remain unexplored. This study investigated the impact of EVsHSHS on angiogenesis using rats with permanent middle cerebral artery occlusion (pMCAO) and brain microvascular endothelial cells (BMECs) subjected to oxygen-glucose deprivation (OGD). Results demonstrated that EVsHSHS promoted the proliferation, migration, and tube formation of BMECs in vitro. In vivo, high doses of EVsHSHS exhibited better performance than equivalent doses of unmodified EPC-derived EVs in reducing cerebral infarction volume, improving cortical blood perfusion, decreasing neurological deficit scores, and increasing cortical microvessel density at day 7 post-modeling. The pro-angiogenic effects of EVsHSHS following cerebral ischemia were associated with the regulation of miR-126 and the PIK3R2/PI3K/AKT pathway.

Keywords:  Angiogenesis; Cerebral ischemia; Extracellular vesicles; Houshiheisan; miR-126

DOI:  https://doi.org/10.1038/s41598-024-78717-4
Cardiovasc Res. 2024 Nov 11. pii: cvae243. [Epub ahead of print]

miR-24-3p secreted as extracellular vesicle cargo by cardiomyocytes inhibits fibrosis in human cardiac microtissues.

Giorgia Senesi, Alessandra M Lodrini, Shafeeq Mohammed, Simone Mosole, Jesper Hjortnaes, Rogier J A Veltrop, Bela Kubat, Davide Ceresa, Sara Bolis, Andrea Raimondi, Tiziano Torre, Paolo Malatesta, Marie-José Goumans, Francesco Paneni, Giovanni G Camici, Lucio Barile, Carolina Balbi, Giuseppe Vassalli.

BACKGROUND AND AIMS: Cardiac fibrosis in response to injury leads to myocardial stiffness and heart failure. At the cellular level, fibrosis is triggered by the conversion of cardiac fibroblasts (CF) into extracellular matrix-producing myofibroblasts. miR-24-3p regulates this process in animal models. Here, we investigated whether miR-24-3p plays similar roles in human models.
METHODS AND RESULTS: Gain- and loss-of-function experiments were performed using human induced pluripotent stem cell-derived cardiomyocytes (hCM) and primary hCF under normoxic or ischaemia-simulating conditions. hCM-derived extracellular vesicles (EVs) were added to hCF. Similar experiments were performed using three-dimensional human cardiac microtissues and ex vivo-cultured human cardiac slices.hCF transfection with miR-24-3p mimic prevented TGFβ1-mediated induction of FURIN, CCND1 and SMAD4-miR-24-3p target genes participating in TGFβ1-dependent fibrinogenesis -, regulating hCF-to-myofibroblast conversion. hCM secreted miR-24-3p as EV cargo. hCM-derived EVs modulated hCF activation. Ischaemia-simulating conditions induced miR-24-3p depletion in hCM-EVs and microtissues. Similarly, hypoxia downregulated miR-24-3p in cardiac slices. Analyses of clinical samples revealed decreased miR-24-3p levels in circulating EVs in acute myocardial infarction (AMI) patients, compared with healthy subjects. Post-mortem RNAScope analysis showed miR-24-3p downregulation in myocardium from AMI patients, compared with patients who died from noncardiac diseases. Berberin, a plant-derived agent with miR-24-3p-stimulatory activity, increased miR-24-3p contents in hCM-EVs, downregulated FURIN, CCND1 and SMAD4, and inhibited fibrosis in cardiac microtissues.
CONCLUSIONS: These findings suggest that hCM may control hCF activation through miR-24-3p secreted as EV cargo. Ischaemia impairs this mechanism, favouring fibrosis.

DOI: https://doi.org/10.1093/cvr/cvae243
Elife. 2024 Nov 15. pii: e95720. [Epub ahead of print]13

Luminal epithelial cells integrate variable responses to aging into stereotypical changes that underlie breast cancer susceptibility.

Rosalyn W Sayaman, Masaru Miyano, Eric G Carlson, Parijat Senapati, Arrianna Zirbes, Sundus F Shalabi, Michael E Todhunter, Victoria E Seewaldt, Susan L Neuhausen, Martha R Stampfer, Dustin E Schones, Mark LaBarge.

  Effects from aging in single cells are heterogenous, whereas at the organ- and tissue-levels aging phenotypes tend to appear as stereotypical changes. The mammary epithelium is a bilayer of two major phenotypically and functionally distinct cell lineages: luminal epithelial and myoepithelial cells. Mammary luminal epithelia exhibit substantial stereotypical changes with age that merit attention because these cells are the putative cells-of-origin for breast cancers. We hypothesize that effects from aging that impinge upon maintenance of lineage fidelity increase susceptibility to cancer initiation. We generated and analyzed transcriptomes from primary luminal epithelial and myoepithelial cells from younger <30 (y)ears old and older >55y women. In addition to age-dependent directional changes in gene expression, we observed increased transcriptional variance with age that contributed to genome-wide loss of lineage fidelity. Age-dependent variant responses were common to both lineages, whereas directional changes were almost exclusively detected in luminal epithelia and involved altered regulation of chromatin and genome organizers such as SATB1. Epithelial expression of gap junction protein GJB6 increased with age, and modulation of GJB6 expression in heterochronous co-cultures revealed that it provided a communication conduit from myoepithelial cells that drove directional change in luminal cells. Age-dependent luminal transcriptomes comprised a prominent signal that could be detected in bulk tissue during aging and transition into cancers. A machine learning classifier based on luminal-specific aging distinguished normal from cancer tissue and was highly predictive of breast cancer subtype. We speculate that luminal epithelia are the ultimate site of integration of the variant responses to aging in their surrounding tissue, and that their emergent phenotype both endows cells with the ability to become cancer-cells-of-origin and represents a biosensor that presages cancer susceptibility.

Keywords:  cancer biology; computational biology; human; systems biology

DOI:  https://doi.org/10.7554/eLife.95720
Prog Lipid Res. 2024 Nov 07. pii: S0163-7827(24)00036-5. [Epub ahead of print] 101303

Lipid sensing by PPARα: Role in controlling hepatocyte gene regulatory networks and the metabolic response to fasting.

Anne Fougerat, Justine Bruse, Arnaud Polizzi, Alexandra Montagner, Hervé Guillou, Walter Wahli.

  Peroxisome proliferator-activated receptors (PPARs) constitute a small family of three nuclear receptors that act as lipid sensors, and thereby regulate the transcription of genes having key roles in hepatic and whole-body energy homeostasis, and in other processes (e.g., inflammation), which have far-reaching health consequences. Peroxisome proliferator-activated receptor isotype α (PPARα) is expressed in oxidative tissues, particularly in the liver, carrying out critical functions during the adaptive fasting response. Advanced omics technologies have provided insight into the vast complexity of the regulation of PPAR expression and activity, as well as their downstream effects on the physiology of the liver and its associated metabolic organs. Here, we provide an overview of the gene regulatory networks controlled by PPARα in the liver in response to fasting. We discuss impacts on liver metabolism, the systemic repercussions and benefits of PPARα-regulated ketogenesis and fibroblast growth factor 21 (FGF21) production, a fasting- and stress-inducible metabolic hormone. We also highlight current challenges in using novel methods to further improve our knowledge of PPARα in health and disease.

Keywords:  fasting; fibroblast growth factor 21 (FGF21); gene expression; ketogenesis; peroxisome proliferator-activated receptors (PPARs)

DOI:  https://doi.org/10.1016/j.plipres.2024.101303
Cardiovasc Diagn Ther. 2024 Oct 31. 14(5): 798-809

Role of STK38L in atrial fibrillation-associated myocardial fibrosis: findings from RNA-seq analysis.

Yu Zhang, Ru Zhang, Xiaochen Wang, Sihua Fang, Bangning Wang.

   Background: Myocardial fibrosis is a key pathological feature of many cardiovascular diseases, leading to cardiac dysfunction. Transforming growth factor β1 (TGF-β1) induces the proliferation and activation of cardiac fibroblasts (CFs), key contributors to myocardial fibrosis. To explore the mechanism underlying myocardial fibrosis, we aimed to determine whether serine/threonine kinase 38 like (STK38L) contributes to the development of myocardial fibrosis by regulating the proliferation and activation of CFs triggered by TGF-β1.
Methods: In this study, atrial tissue samples from atrial fibrillation (AF) patients with features of myocardial fibrosis (a category of atrial cardiomyopathy) and sinus rhythm (SR) patients without myocardial fibrosis were collected for RNA sequencing (RNA-seq). The specific molecule STK38L was identified. Primary mouse CFs were activated with TGF-β1 and subsequently transfected with STK38L-small interfering RNA (siRNA). The effect of STK38L-siRNA on fibroblast activation and proliferation was assessed using scratch and Cell Counting Kit-8 (CCK-8) assays. Furthermore, a mouse model of myocardial fibrosis induced by continuous subcutaneous injection of isoprenaline (ISO) was established to assess STK38L expression levels. Molecular experiments confirmed the expression of STK38L in fibrotic atrial tissues, ventricular tissues of ISO mouse, and primary CFs of neonatal mice.
Results: We identified 1,870 genes exhibiting differential expression in the RNA-seq data between the AF and SR groups. Masson's trichrome staining revealed increased fibrosis in the heart tissues of the AF group. Elevated levels of STK38L were observed in the atrial tissues of the AF group and in the TGF-β1-stimulated primary mouse CFs. In vitro, STK38L knockdown suppressed mouse CFs activation and proliferation. Additionally, in vivo experiments showed that elevated mRNA levels of STK38L, periostin (POSTN), and collagen type I alpha 1 chain (COL1A1) in ISO-treated mouse hearts correlated with greater myocardial fibrosis, suggesting that STK38L plays an important role in the development of fibrosis.
Conclusions: This study revealed a significant correlation between increased STK38L expression and AF characterized by atrial fibrosis as well as between STK38L expression and the TGF-β1-related induction of myocardial fibrosis. Additionally, STK38L knockdown was shown to suppress CFs activation and proliferation under TGF-β1 stimulation. These findings suggest an important role of STK38L in the development of fibrosis, and help screen for new strategies to treat this complex disease.

Keywords:  Atrial fibrillation (AF); atrial cardiomyopathy (ACM); myocardial fibrosis; serine/threonine kinase 38 like (STK38L)

DOI:  https://doi.org/10.21037/cdt-24-164