bims-midhyp 2023-11-12 papers

bims-midhyp

Biomed News

on Mitochondrial dysfunction and hypoxia

Issue of 2023–11–12
nine papers selected by
Alia Ablieh, Universität Heidelberg

Heat-shock protein A12A attenuates oxygen-glucose deprivation/reoxygenation-induced human brain microvascular endothelial cell dysfunction via PGC-1α/SIRT3 pathway.
The chromatin remodeling protein BRG1 contributes to liver ischemia-reperfusion injury by regulating NOXA expression.
DNAJB6 mutants display toxic gain of function through unregulated interaction with Hsp70 chaperones.
Endothelial heterogeneity and their relevance in cardiac development and coronary artery disease.
Decoding the molecular interplay in the central dogma: An overview of mass spectrometry-based methods to investigate protein-metabolite interactions.
Cardiac energy metabolism disorder mediated by energy substrate imbalance and mitochondrial damage upon tebuconazole exposure.
Endothelial cells differentially sense laminar and disturbed flows by altering the lipid order of their plasma and mitochondrial membranes.
DNAJB12 and DNJB14 are non-redundant Hsp40 redox chaperones involved in endoplasmic reticulum protein reflux.
Tissue-specific Cre driver mice to study vascular diseases.

Drug Dev Res. 2023 Nov 09.

Heat-shock protein A12A attenuates oxygen-glucose deprivation/reoxygenation-induced human brain microvascular endothelial cell dysfunction via PGC-1α/SIRT3 pathway.

Jun Li, Shouyin Shen, Haiyan Shen.

  Ischemic stroke is a life-threatening brain disease with the leading cause of disability and mortality worldwide. Heat-shock protein A12A (HSPA12A) is recognized as a neuroprotective target for treating ischemic stroke; however, its regulatory mechanism has been not fully elucidated yet. Human brain microvascular endothelial cells (hBMECs) were induced by oxygen-glucose deprivation/reoxygenation (OGD/R) to mimic ischemic stroke. Gain- and loss-of-function experiments were conducted to explore the regulation of HSAPA12 and PGC-1α. Cell viability, apoptosis, and permeability were assessed by CCK-8, TUNEL, and transendothelial electrical resistance (TEER) assays, respectively. The expression of HSPA12A and corresponding proteins was measured by western blot. Cell immunofluorescence was adopted to evaluate ZO-1 expression. THP-1 cells were applied to adhere hBMECs in vitro to simulate leukocyte adhesion in the brain. HSPA12A was downregulated in OGD/R-treated hBMECs. HSPA12A overexpression significantly suppressed OGD/R-induced cell viability loss and apoptosis in hBMECs. Meanwhile, HSPA12A overexpression attenuated blood-brain barrier (BBB) integrity in OGD/R-induced hBMECs, evidenced by the restored TEER value and the upregulated ZO-1, occludin, and claudin-5. HSPA12A also restricted OGD/R-induced attachment of THP-1 cells to hBMECs, accompanied with downregulating ICAM-1 and VCAM-1. Additionally, OGD/R-caused downregulation of PGC-1α/SIRT3 in hBMECs was partly restored by HSPA12A overexpression. Furthermore, the above effects of HSPA12A on OGD/R-induced hBMECs injury were partly reversed by PGC-1α knockdown. HSPA12A plays a protective role against OGD/R-induced hBMECs injury by upregulating PGC-1α, providing a potential neuroprotective role of HSPA12A in ischemic stroke.

Keywords:  HSPA12A; PGC-1α; blood-brain barrier; brain microvascular endothelial cell

DOI:  https://doi.org/10.1002/ddr.22130
Life Sci. 2023 Nov 03. pii: S0024-3205(23)00870-6. [Epub ahead of print]334 122235

The chromatin remodeling protein BRG1 contributes to liver ischemia-reperfusion injury by regulating NOXA expression.

Nan Li, Hong Liu, Yujia Xue, Qiang Zhu, Zhiwen Fan.

   AIMS: Hepatic ischemia-reperfusion injury (IRI) is a common complication secondary to liver transplantation. Extensive death of hepatocytes, typically in the form of apoptosis, is observed in and contributes to IRI. In the present study we investigated the role of BRG1 (encoded by Smarca4), a chromatin remodeling protein, in the pathogenesis of liver IRI focusing on the transcriptional mechanism and translational potential.
METHODS: Smarca4f/f mice were crossed to Alb-Cre mice to generate hepatocytes-specific BRG1 knockout mice (CKO). Alterations in cellular transcriptome were evaluated by RNA-seq.
RESULTS: BRG1 expression was up-regulated in liver tissues of mice subjected to I/R and in hepatocytes exposed to hypoxia-reoxygenation (H/R). Compared to wild type (WT) littermates, the BRG1 CKO mice displayed significant amelioration of liver injury following ischemia-reperfusion as evidenced by decreased ALT/AST levels and cell apoptosis. Primary hepatocytes isolated from the CKO mice were protected from H/R-induced apoptosis compared to those from the WT mice. RNA-seq analysis revealed phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1, also known as NOXA) as a novel target for BRG1. Consistently, NOXA knockdown attenuated liver IRI in mice. More importantly, administration of a small-molecule BRG1 inhibitor (PFI-3) protected the mice from liver IRI.
CONCLUSIONS: Our data uncover a pivotal role for BRG1 in liver IRI and suggest that targeting BRG1 with small-molecule inhibitors can be considered as a reasonable therapeutic strategy.

Keywords:  Apoptosis; Hepatocyte; Ischemia-reperfusion injury; Transcriptional regulation

DOI:  https://doi.org/10.1016/j.lfs.2023.122235
Nat Commun. 2023 Nov 03. 14(1): 7066

DNAJB6 mutants display toxic gain of function through unregulated interaction with Hsp70 chaperones.

Meital Abayev-Avraham, Yehuda Salzberg, Dar Gliksberg, Meital Oren-Suissa, Rina Rosenzweig.

Molecular chaperones are essential cellular components that aid in protein folding and preventing the abnormal aggregation of disease-associated proteins. Mutations in one such chaperone, DNAJB6, were identified in patients with LGMDD1, a dominant autosomal disorder characterized by myofibrillar degeneration and accumulations of aggregated protein within myocytes. The molecular mechanisms through which such mutations cause this dysfunction, however, are not well understood. Here we employ a combination of solution NMR and biochemical assays to investigate the structural and functional changes in LGMDD1 mutants of DNAJB6. Surprisingly, we find that DNAJB6 disease mutants show no reduction in their aggregation-prevention activity in vitro, and instead differ structurally from the WT protein, affecting their interaction with Hsp70 chaperones. While WT DNAJB6 contains a helical element regulating its ability to bind and activate Hsp70, in LGMDD1 disease mutants this regulation is disrupted. These variants can thus recruit and hyperactivate Hsp70 chaperones in an unregulated manner, depleting Hsp70 levels in myocytes, and resulting in the disruption of proteostasis. Interfering with DNAJB6-Hsp70 binding, however, reverses the disease phenotype, suggesting future therapeutic avenues for LGMDD1.

DOI: https://doi.org/10.1038/s41467-023-42735-z
Vascul Pharmacol. 2023 Nov 06. pii: S1537-1891(23)00102-7. [Epub ahead of print] 107242

Endothelial heterogeneity and their relevance in cardiac development and coronary artery disease.

Rosalinda Madonna.

  Micro- and macrovascular endothelial cells (ECs) are characterized by structural and functional heterogeneity, which is also reflected in their secretory activity. The root of this heterogeneity and related regulatory mechanisms are still poorly understood. During embryogenesis, microvascular ECs participate in organogenesis prior to the development of the fetal circulation, suggesting that ECs are capable of releasing paracrine trophogens, termed angiocrine factors (AFs). These are angiocrine growth factors, adhesion molecules, and chemokines, which are intended to promote morphogenesis and repair of the adjacent parenchyma/stroma where the vessels are located. There is a tissue and organ-specificity of AFs that traces the heterogeneity of ECs. This AF heterogeneity also traces how ECs respond to pathological conditions or exposure to cardiovascular risk factors. The study of the mechanisms that regulate endothelial and paracrine heterogeneity and that contribute to endotheliopathy represents a broad and as yet understudied area of research. A better understanding of the cellular and molecular mechanisms that regulate this heterogeneity, leading to endotheliopathy is an exciting challenge. In this brief review we will discuss experimental advances in the heterogeneity of ECs and their AF, with a focus on their involvement in the pathogenesis of coronary artery disease.

Keywords:  Angiocrine factors; Atherosclerosis; Cardiac development diabetes; Endothelial cells; Heterogeneity

DOI:  https://doi.org/10.1016/j.vph.2023.107242
Proteomics. 2023 Nov 06. e2200533

Decoding the molecular interplay in the central dogma: An overview of mass spectrometry-based methods to investigate protein-metabolite interactions.

Paolo Stincone, Amira Naimi, Anthony J Saviola, Raphael Reher, Daniel Petras.

  With the emergence of next-generation nucleotide sequencing and mass spectrometry-based proteomics and metabolomics tools, we have comprehensive and scalable methods to analyze the genes, transcripts, proteins, and metabolites of a multitude of biological systems. Despite the fascinating new molecular insights at the genome, transcriptome, proteome and metabolome scale, we are still far from fully understanding cellular organization, cell cycles and biology at the molecular level. Significant advances in sensitivity and depth for both sequencing as well as mass spectrometry-based methods allow the analysis at the single cell and single molecule level. At the same time, new tools are emerging that enable the investigation of molecular interactions throughout the central dogma of molecular biology. In this review, we provide an overview of established and recently developed mass spectrometry-based tools to probe metabolite-protein interactions-from individual interaction pairs to interactions at the proteome-metabolome scale. This article is protected by copyright. All rights reserved.

Keywords:  Mass Spectrometry; Metabolite-Protein interaction; Metabolomics; Proteomics; Target ID

DOI:  https://doi.org/10.1002/pmic.202200533
J Environ Sci (China). 2024 Feb;pii: S1001-0742(22)00502-2. [Epub ahead of print]136 270-278

Cardiac energy metabolism disorder mediated by energy substrate imbalance and mitochondrial damage upon tebuconazole exposure.

Tingting Ku, Jindong Hu, Mengmeng Zhou, Yuanyuan Xie, Yutong Liu, Xin Tan, Lin Guo, Guangke Li, Nan Sang.

  Tebuconazole exposure has been described as an increasing hazard to human health. An increasing number of recent studies have shown a positive association between tebuconazole exposure and cardiovascular disease risk, which is characterized by the reduction of adenosine triphosphate (ATP) synthesis. However, researches on the damage of tebuconazole exposure to energy metabolism and the related molecular mechanisms are limited. In the present study, male C57BL/6 mice were treated with tebuconazole at different low concentrations for 4 weeks. The results indicated that tebuconazole could accumulate in the heart and further induce the decrease of ATP content in the mouse heart. Importantly, tebuconazole induced an obvious shift in substrate utilization of fatty acid and glucose by disrupting their corresponding transporters (GLUT1, GLUT4, CD36, FABP3 and FATP1) expression, and significantly repressed the expression of mitochondrial biogenesis (Gabpa and Tfam) and oxidative phosphorylation (CS, Ndufa4, Sdhb, Cox5a and Atp5b) related genes in a dose-dependent manner. Further investigation revealed that these alterations were related to the IRS1/AKT and PPARγ/RXRα pathways. These findings contribute to a better understanding of triazole fungicide-induced cardiovascular disease by revealing the key indicators associated with this phenomenon.

Keywords:  Cardiotoxicity; Energy metabolic disorders; Energy substrate; Mitochondrial damage; Tebuconazole

DOI:  https://doi.org/10.1016/j.jes.2022.10.012
Am J Physiol Cell Physiol. 2023 Nov 06.

Endothelial cells differentially sense laminar and disturbed flows by altering the lipid order of their plasma and mitochondrial membranes.

Kimiko Yamamoto, Yuji Shimogonya, Ryohei Maeno, Kenshiroh Kawabe, Joji Ando.

  Endothelial cells (ECs) experience two different blood flow patterns: laminar and disturbed flow. Their responses to laminar flow contribute to vascular homeostasis, whereas their responses to disturbed flow result in EC dysfunction and vascular diseases. However, it remains unclear how ECs differentially sense laminar and disturbed flow and trigger signaling that elicits different responses. Here, we showed that ECs differentially sense laminar and disturbed flows by altering the lipid order of their plasma and mitochondrial membranes in opposite directions. This results in distinct changes in mitochondrial function, namely, increased adenosine triphosphate (ATP) production for laminar flow and increased hydrogen peroxide (H2O2) release for disturbed flow, leading to ATP- and H2O2-mediated signaling, respectively. When cultured human aortic ECs were subjected to laminar or disturbed flow in flow-loading devices, the lipid order of their plasma membranes immediately decreased in response to laminar flow and increased in response to disturbed flow. Laminar flow also decreased the lipid order of mitochondrial membranes and increased mitochondrial ATP production. In contrast, disturbed flow increased the lipid order of mitochondrial membranes and increased the release of H2O2 from the mitochondria. The addition of cholesterol to the cells increased the lipid order of both membranes and abrogated laminar flow-induced ATP production, while treatment of the cells with a cholesterol-depleting reagent, methyl-β cyclodextrin, decreased the lipid order of both membranes and abolishτed disturbed flow-induced H2O2 release, indicating that changes in the membrane lipid order and/or cholesterol content are closely linked to flow-induced changes in mitochondrial functions.

Keywords:  Disturbed flow; Endothelial cells; Membrane lipid order; Mitochondria; Shear stress

DOI:  https://doi.org/10.1152/ajpcell.00393.2023
Biochim Biophys Acta Gen Subj. 2023 Nov 03. pii: S0304-4165(23)00200-3. [Epub ahead of print]1868(1): 130502

DNAJB12 and DNJB14 are non-redundant Hsp40 redox chaperones involved in endoplasmic reticulum protein reflux.

Aline Dias da Purificação, Victor Debbas, Leonardo Yuji Tanaka, Gabriele Verônica de Mello Gabriel, João Wosniak Júnior, Tiphany Coralie De Bessa, Sheila Garcia-Rosa, Francisco Rafael Martins Laurindo, Percillia Victoria Santos Oliveira.

   BACKGROUND: The endoplasmic reticulum (ER) transmembrane chaperones DNAJB12(B12) and DNAJB14(B14) are cofactors that cooperate with cytosolic Heat Shock-70 protein (HSC70) facilitating folding/degradation of nascent membrane proteins and supporting the ER-membrane penetration of viral particles. Here, we assessed structural/functional features of B12/B14 with respect to their regulation by ER stress and their involvement in ER stress-mediated protein reflux.
METHODS: We investigated the effect of Unfolded Protein Response(UPR)-eliciting drugs on the expression/regulation of B12-B14 and their roles in ER-to-cytosol translocation of Protein Disulfide Isomerase-A1(PDI).
RESULTS: We show that B12 and B14 are similar but do not seem redundant. They share predicted structural features and show high homology of their cytosolic J-domains, while their ER-lumen DUF1977 domains are quite dissimilar. Interactome analysis suggested that B12/B14 associate with different biological processes. UPR activation did not significantly impact on B12 gene expression, while B14 transcripts were up-regulated. Meanwhile, B12 and B14 (33.4 kDa isoform) protein levels were degraded by the proteasome upon acute reductive challenge. Also, B12 degradation was impaired upon sulfenic-acid trapping by dimedone. We originally report that knockdown of B12/B14 and their cytosolic partner SGTA in ER-stressed cells significantly impaired the amount of the ER redox-chaperone PDI in a cytosolic-enriched fraction. Additionally, B12 but not B14 overexpression increased PDI relocalization in non-stressed cells.
CONCLUSIONS AND GENERAL SIGNIFICANCE: Our findings reveal that B12/B14 regulation involves thiol redox processes that may impact on their stability and possibly on physiological effects. Furthermore, we provide novel evidence that these proteins are involved in UPR-induced ER protein reflux.

Keywords:  DNAJB12; DNAJB14; ER protein reflux; Endoplasmic reticulum stress

DOI:  https://doi.org/10.1016/j.bbagen.2023.130502
Vascul Pharmacol. 2023 Nov 03. pii: S1537-1891(23)00101-5. [Epub ahead of print]153 107241

Tissue-specific Cre driver mice to study vascular diseases.

Qing Rex Lyu, Kailong Fu.

  Vascular diseases, including atherosclerosis and abdominal aneurysms, are the primary cause of mortality and morbidity among the elderly worldwide. The life quality of patients is significantly compromised due to inadequate therapeutic approaches and limited drug targets. To expand our comprehension of vascular diseases, gene knockout (KO) mice, especially conditional knockout (cKO) mice, are widely used for investigating gene function and mechanisms of action. The Cre-loxP system is the most common method for generating cKO mice. Numerous Cre driver mice have been established to study the main cell types that compose blood vessels, including endothelial cells, smooth muscle cells, and fibroblasts. Here, we first discuss the characteristics of each layer of the arterial wall. Next, we provide an overview of the representative Cre driver mice utilized for each of the major cell types in the vessel wall and their most recent applications in vascular biology. We then go over Cre toxicity and discuss the practical methods for minimizing Cre interference in experimental outcomes. Finally, we look into the future of tissue-specific Cre drivers by introducing the revolutionary single-cell RNA sequencing and dual recombinase system.

Keywords:  Conditional knockout mice; Cre toxicity; Cre-loxP system; Endothelial cells; Smooth muscle cells; Vascular disease

DOI:  https://doi.org/10.1016/j.vph.2023.107241